PIXE analysis of Thaumatococcus danielli in Osun State of Nigeria

NASA Astrophysics Data System (ADS)

Olabanji, S. O.; Osinkolu, G. A.; Pelemo, D. A.; Obiajunwa, E. I.; Oladele, A. T.

2014-01-01

Particle-induced X-ray emission (PIXE) technique was employed for the determination of elemental compositions of Thaumatococcus danielli (T. danielli) {Marantaceae} (Benn.) Benth [miraculous berry] in Osun State of Nigeria. The objective is to show the usefulness of T. danielli and especially the beneficial effects of the mineral concentrations from the leaves and fruits of T. danielli. The results show the detection of seventeen elements at different concentrations, and their beneficial effects to humans were discussed.

14th International Conference on Particle Induced X-ray Emission ("PIXE 2015")

NASA Astrophysics Data System (ADS)

Przybyłowicz, Wojciech Józef; Pineda-Vargas, Carlos

2015-11-01

This special issue of Nuclear Instruments and Methods in Physics Research B contains the proceedings of the 14th International Conference on Particle Induced X-ray Emission ("PIXE 2015") that was held in Somerset West (South Africa) from 25th February to 3rd March 2015.

PIXE analysis on Maya blue in Prehispanic and colonial mural paintings

NASA Astrophysics Data System (ADS)

Sánchez del Río, M.; Martinetto, P.; Solís, C.; Reyes-Valerio, C.

2006-08-01

Particle induced X-ray emission (PIXE) experiments have been carried out at the AGLAE facility (Paris) on several mural samples containing Maya blue from different Prehispanic archaeological sites (Cacaxtla, El Tajín, Tamuin, Santa Cecilia Acatitlán) and from several colonial convents in the Mexican plateau (Jiutepec, Totimehuacán, Tezontepec and Cuauhtinchán). The analysis of the concentration of several elements permitted to extract some information on the technique used for painting the mural, usually fresco. Principal component analysis permitted to classify the samples into groups. This grouping is discussed in relation to geographic and historic data.

PIXE analysis of ancient Chinese Changsha porcelain

NASA Astrophysics Data System (ADS)

Lin, E. K.; Yu, Y. C.; Wang, C. W.; Liu, T. Y.; Wu, C. M.; Chen, K. M.; Lin, S. S.

1999-04-01

In this work, proton induced X-ray emission (PIXE) method was applied for the analysis of ancient Chinese Changsha porcelain produced in the Tang dynasty (AD 618-907). A collection of glazed potsherds was obtained in the complex of the famous kiln site at Tongguan, Changsha city, Hunan province. Studies of elemental composition were carried out on ten selected Changsha potsherds. Minor and trace elements such as Ti, Mn, Fe, Co, Cu, Rb, Sr, and Zr in the material of the porcelain glaze were determined. Variation of these elements from sample to sample was investigated. Details of results are presented and discussed.

PIXE Analysis of Aerosol and Soil Samples Collected in the Adirondack Mountains

NASA Astrophysics Data System (ADS)

Yoskowitz, Joshua; Ali, Salina; Nadareski, Benjamin; Labrake, Scott; Vineyard, Michael

2014-09-01

We have performed an elemental analysis of aerosol and soil samples collected at Piseco Lake in Upstate New York using proton induced X-ray emission spectroscopy (PIXE). This work is part of a systematic study of airborne pollution in the Adirondack Mountains. Of particular interest is the sulfur content that can contribute to acid rain, a well-documented problem in the Adirondacks. We used a nine-stage cascade impactor to collect the aerosol samples near Piseco Lake and distribute the particulate matter onto Kapton foils by particle size. The soil samples were also collected at Piseco Lake and pressed into cylindrical pellets for experimentation. PIXE analysis of the aerosol and soil samples were performed with 2.2-MeV proton beams from the 1.1-MV Pelletron accelerator in the Union College Ion-Beam Analysis Laboratory. There are higher concentrations of sulfur at smaller particle sizes (0.25-1 μm), suggesting that it could be suspended in the air for days and originate from sources very far away. Other elements with significant concentrations peak at larger particle sizes (1-4 μm) and are found in the soil samples, suggesting that these elements could originate in the soil. The PIXE analysis will be described and the resulting data will be presented.

Comparison of PIXE and XRF analysis of airborne particulate matter samples collected on Teflon and quartz fibre filters

NASA Astrophysics Data System (ADS)

Chiari, M.; Yubero, E.; Calzolai, G.; Lucarelli, F.; Crespo, J.; Galindo, N.; Nicolás, J. F.; Giannoni, M.; Nava, S.

2018-02-01

Within the framework of research projects focusing on the sampling and analysis of airborne particulate matter, Particle Induced X-ray Emission (PIXE) and Energy Dispersive X-ray Fluorescence (ED-XRF) techniques are routinely used in many laboratories throughout the world to determine the elemental concentration of the particulate matter samples. In this work an inter-laboratory comparison of the results obtained from analysing several samples (collected on both Teflon and quartz fibre filters) using both techniques is presented. The samples were analysed by PIXE (in Florence, at the 3 MV Tandetron accelerator of INFN-LABEC laboratory) and by XRF (in Elche, using the ARL Quant'X EDXRF spectrometer with specific conditions optimized for specific groups of elements). The results from the two sets of measurements are in good agreement for all the analysed samples, thus validating the use of the ARL Quant'X EDXRF spectrometer and the selected measurement protocol for the analysis of aerosol samples. Moreover, thanks to the comparison of PIXE and XRF results on Teflon and quartz fibre filters, possible self-absorption effects due to the penetration of the aerosol particles inside the quartz fibre-filters were quantified.

The Elemental Analysis of Biological and Environmental Materials Using a 2MEV Proton Beam

NASA Astrophysics Data System (ADS)

Arshed, Waheed

Available from UMI in association with The British Library. A programme has been developed to simulate the proton induced x-ray emission (PIXE) spectra and its uses have been described. The PIXE technique has been applied to the analysis of new biological reference materials which consist of IAEA human diet samples and NIST leaf samples. Homogeneity of these and two existing reference materials, IAEA soil -7 and Bowen's kale, has also been determined at the mug scale. A subsample representative of a material is ascertained by determination of sampling factors for the elements detected in the material. Proton induced gamma-ray emission (PIGE) analysis in conjunction with PIXE has been employed to investigate F and other elemental concentrations found in human teeth samples. The mean F concentration in enamel and dentine parts of teeth followed an age dependent model. Concentrations of Ca and P were found to be higher in the enamel than in the dentine. Analysis of blood and its components in the study of elemental models in sickle cell disease in Nigerians has been carried out. Comparisons revealed that Cl, Ca and Cu were at higher levels whereas K, Fe, Zn and Rb were at lower levels in the whole blood of the sicklers compared to controls. Similar results were obtained for the erythrocytes except that Br was found at higher concentration in erythrocytes of the sicklers. Higher concentrations of Cl, K, Fe and Cu were also observed in plasma of the sicklers compared to controls. PIXE and scanning electron microscopy (SEM) were used in the characterization of the Harmattan dust particulates collected at Kano and Ife. Most of the elements were found to be at higher concentrations as compared to those found in Recife (Brazil) and Toronto (Canada). The value of total suspended particulate was above the relevant national air quality standards. PIXE in conjunction with Rutherford backscattering spectrometry and instrumental neutron activation analysis was employed in the analysis of soil samples detecting 31 elements. The results have been discussed with reference to elemental concentrations and Ca/Si ratio. The latter was a valid indicator of soil pollution by the cement dust. (Abstract shortened by UMI.).

PIXE analysis of Nigerian flour and bread samples

NASA Astrophysics Data System (ADS)

Olise, Felix S.; Fernandes, Adriana M.; Cristina Chaves, P.; Taborda, Ana; Reis, Miguel A.

2014-01-01

The alleged use of potassium bromate (KBrO3) in bread baking led a few authors to report on the chemical methods for the determination of KBrO3 levels in bread. In order to examine the potentials of a non chemical particle induced X-ray emission (PIXE) method for this purpose, six sets of samples, each composed of flour, dough and bread from a production batch were analysed. The samples were obtained from six different bakers of bread at Ile-Ife, Nigeria. The flour samples were air-dried while others were freeze dried at about -16 °C. The samples were homogenised in an agate mortar and then pelletised. Samples were analysed at the CTN standard PIXE setup and standard procedures for thick target samples analysis were followed. In some samples significant concentrations of bromine were found. In the present work we present possible explanations for the presence of this potentially dangerous contaminant in the samples.

PIXE and XRF Analysis of Roman Denarii

NASA Astrophysics Data System (ADS)

Fasano, Cecilia; Raddell, Mark; Manukyan, Khachatur; Stech, Edward; Wiescher, Michael

2017-09-01

A set of Roman Denarii from the republican to the imperial period (140BC-240AD) has been studied using X-ray fluorescent (XRF) scanning and proton induced x-ray emission (PIXE) techniques. XRF and PIXE are commonly used in the study of cultural heritage objects because they are nondestructive. The combination of these two methods is also unique because of the ability to penetrate the sample with a broader spectrum of depths and energies than either could achieve on its own. The coins are from a large span of Roman history and their analysis serves to follow the economic and political change of the era using the relative silver and copper contents in each sample. In addition to analyzing the samples, the study sought to compare these two common analysis techniques and to explore the use of a standard to examine any shortcomings in either of the methods. Data sets were compared and then adjusted to a calibration curve which was created from the analysis of a number of standard solutions. The concentrations of the standard solutions were confirmed using inductively coupled plasma spectroscopy. Through this we were able to assemble results which will progress the basis of understanding of PIXE and XRF techniques as well as increase the wealth of knowledge of Ancient Roman currency.

Trace elemental analysis of Indian natural moonstone gems by PIXE and XRD techniques.

PubMed

Venkateswara Rao, R; Venkateswarulu, P; Kasipathi, C; Sivajyothi, S

2013-12-01

A selected number of Indian Eastern Ghats natural moonstone gems were studied with a powerful nuclear analytical and non-destructive Proton Induced X-ray Emission (PIXE) technique. Thirteen elements, including V, Co, Ni, Zn, Ga, Ba and Pb, were identified in these moonstones and may be useful in interpreting the various geochemical conditions and the probable cause of their inceptions in the moonstone gemstone matrix. Furthermore, preliminary XRD studies of different moonstone patterns were performed. The PIXE technique is a powerful method for quickly determining the elemental concentration of a substance. A 3MeV proton beam was employed to excite the samples. The chemical constituents of moonstones from parts of the Eastern Ghats geological formations of Andhra Pradesh, India were determined, and gemological studies were performed on those gems. The crystal structure and the lattice parameters of the moonstones were estimated using X-Ray Diffraction studies, trace and minor elements were determined using the PIXE technique, and major compositional elements were confirmed by XRD. In the present work, the usefulness and versatility of the PIXE technique for research in geo-scientific methodology is established. © 2013 Elsevier Ltd. All rights reserved.

PIXE Analysis of Ceramic Artifacts

NASA Astrophysics Data System (ADS)

High, Elizabeth; Lamm, Larry; Schurr, Mark; Stech, Edward; Wiescher, Michael

2009-10-01

Particle Induced X-ray Emissions, or PIXE, is a nuclear physics technique used as a non-destructive material analysis method which gives a detailed and comprehensive profile of the elemental composition of a target. Using the University of Notre Dame KN and FN accelerators in the ISNAP laboratory a beam of particles, here protons, is accelerated and used to knock out electrons from lower orbitals within the target resulting in characteristic X-rays. Under optimum operating conditions data from PIXE can not only give information about which elements are present in a sample but also their relative abundances in parts per million. In a previous run done in collaboration with the Anthropology Department at the University of Notre Dame pottery shards from the Collier Lodge, located in northwest Indiana, were analyzed and only relative abundances were able to be compared between samples. We are now implementing a new setup into the beam-line which will incorporate the ability to take Rutherford Back Scattering, or RBS, measurements of the beam during the PIXE runs, which will allow for a standard normalization for the runs and give the facility the ability to acquire a more absolute and quantitative analysis of the data. Initial results using the same pottery shards as a comparative data set will be presented.

Proton Induced X-Ray Emission (PIXE): Determining the Concentration of Samples

NASA Astrophysics Data System (ADS)

McCarthy, Mallory; Rodriguez Manso, Alis; Pajouhafsar, Yasmin; J Yennello, Sherry

2017-09-01

We used Proton Induced X-ray Emission (PIXE) as an analysis technique to determine the composition of samples, in particular, the elemental constituents and the concentrations. Each of the samples are bombarded with protons, which in result displaces a lower level electron and causes a higher level electron to fall into its place. This displacement produces characteristic x-rays that are `fingerprints' for each element. The protons supplied for the bombardment are produced and accelerated by the K150 proton beam in the Cyclotron Institute at Texas A&M University. The products are detected by three x-ray detectors: XR-100CR Si-PIN, XR-100SDD, and XR-100T CdTe. The peaks of the spectrum are analyzed using a software analysis tool, GUPIXWIN, to determine the concentration of the known elements of each particular sample. The goals of this work are to test run the Proton Induced X-Ray Emission experimental set up at Texas A&M University (TAMU) and to determine the concentration of thin films containing KBr given by the TAMU Chemical Engineering Department.

Elemental Levels Analyzed by PIXE in Florida Alligators

NASA Astrophysics Data System (ADS)

Kuharik, J. C.; Kravchenko, I. I.; Dunnam, F. E.; Van Rinsvelt, H. A.; Ross, J. P.

2003-08-01

Unusual and alarming mortality of alligators (Alligator mississippiensis) has been reported from Lake Griffin, Florida, where almost 400 dead alligators have been observed since 1997. In addition, the hatch rate for alligator eggs around Lake Griffin fell below 10% and remains low (30-45%) while the normal hatch rate is typically 80%. Standard diagnostic methods have been ineffective in determining the cause of the phenomenon. Many possibilities have been considered including pollutants, nutrition, and toxic algae. Particle Induced X-ray Emission (PIXE) analysis is highly suitable for investigating concentrations of a wide range of elements in animal tissue. Liver, kidney and spinal cord tissues from healthy and sick alligators have been analyzed by PIXE for elemental content. Initial results showed positive correlation between certain elements and neural impairment and morbidity of alligators in Lake Griffin, but have failed to prove significant.

Range verification for eye proton therapy based on proton-induced x-ray emissions from implanted metal markers

NASA Astrophysics Data System (ADS)

La Rosa, Vanessa; Kacperek, Andrzej; Royle, Gary; Gibson, Adam

2014-06-01

Metal fiducial markers are often implanted on the back of the eye before proton therapy to improve target localization and reduce patient setup errors. We aim to detect characteristic x-ray emissions from metal targets during proton therapy to verify the treatment range accuracy. Initially gold was chosen for its biocompatibility properties. Proton-induced x-ray emissions (PIXE) from a 15 mm diameter gold marker were detected at different penetration depths of a 59 MeV proton beam at the CATANA proton facility at INFN-LNS (Italy). The Monte Carlo code Geant4 was used to reproduce the experiment and to investigate the effect of different size markers, materials, and the response to both mono-energetic and fully modulated beams. The intensity of the emitted x-rays decreases with decreasing proton energy and thus decreases with depth. If we assume the range to be the depth at which the dose is reduced to 10% of its maximum value and we define the residual range as the distance between the marker and the range of the beam, then the minimum residual range which can be detected with 95% confidence level is the depth at which the PIXE peak is equal to 1.96 σbkg, which is the standard variation of the background noise. With our system and experimental setup this value is 3 mm, when 20 GyE are delivered to a gold marker of 15 mm diameter. Results from silver are more promising. Even when a 5 mm diameter silver marker is placed at a depth equal to the range, the PIXE peak is 2.1 σbkg. Although these quantitative results are dependent on the experimental setup used in this research study, they demonstrate that the real-time analysis of the PIXE emitted by fiducial metal markers can be used to derive beam range. Further analysis are needed to demonstrate the feasibility of the technique in a clinical setup.

Elemental investigation of Syrian medicinal plants using PIXE analysis

NASA Astrophysics Data System (ADS)

Rihawy, M. S.; Bakraji, E. H.; Aref, S.; Shaban, R.

2010-09-01

Particle induced X-ray emission (PIXE) technique has been employed to perform elemental analysis of K, Ca, Mn, Fe, Cu, Zn, Br and Sr for Syrian medicinal plants used traditionally to enhance the body immunity. Plant samples were prepared in a simple dried base. The results were verified by comparing with those obtained from both IAEA-359 and IAEA-V10 reference materials. Relative standard deviations are mostly within ±5-10% suggest good precision. A correlation between the elemental content in each medicinal plant with its traditional remedial usage has been proposed. Both K and Ca are found to be the major elements in the samples. Fe, Mn and Zn have been detected in good levels in most of these plants clarifying their possible contribution to keep the body immune system in good condition. The contribution of the elements in these plants to the dietary recommended intakes (DRI) has been evaluated. Advantages and limitations of PIXE analytical technique in this investigation have been reviewed.

Total elemental composition of soils contaminated with wastewater irrigation by combining IBA techniques

NASA Astrophysics Data System (ADS)

Huerta, L.; Contreras-Valadez, R.; Palacios-Mayorga, S.; Miranda, J.; Calva-Vasquez, G.

2002-04-01

The purpose of this work was to obtain the total elemental composition of agricultural soils irrigated with well water and wastewater. The studied area is located in the Valle del Mezquital in Hidalgo State, Mexico. The studied soils were collected, every two months during one year. Particle induced X-ray emission (PIXE), Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA) were applied for elemental analysis. PIXE analyses gave elemental contents of major and trace elements (Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Rb, Sr, Y, Zr, and Pb). Total concentrations of Na, Mg, C, N and O were obtained by RBS and NRA. PIXE analyses were carried out with 2 MeV proton beams, RBS with 2 MeV helium ions, while NRA was applied with a 1.2 MeV deuterium beam. Results indicated that heavy metal total concentrations exceed the critical soil total concentrations according to environmental regulations.

Trace-Element Analysis by Use of PIXE Technique on Agricultural Products

NASA Astrophysics Data System (ADS)

Takagi, A.; Yokoyama, R.; Makisaka, K.; Kisamori, K.; Kuwada, Y.; Nishimura, D.; Matsumiya, R.; Fujita, Y.; Mihara, M.; Matsuta, K.; Fukuda, M.

2009-10-01

In order to examine whether a trace-element analysis by PIXE (Particle Induced X-ray Emission) gives a clue to identify production area of agricultural products, we carried out a study on soy beans as an example. In the present study, a proton beam at the energy of 2.3MeV was provided by Van de Graaff accelerator at Osaka University. We used a Ge detector with Be window to measure X-ray spectra. We prepared sample soy beans from China, Thailand, Taiwan, and 7 different areas in Japan. As a result of PIXE analysis, 5 elements, potassium, iron, zinc, arsenic and rubidium, have been identified. There are clear differences in relative amount of trace-elements between samples from different international regions. Chinese beans contain much more Rb than the others, while there are significant differences in Fe and Zn between beans of Thailand and Taiwan. There are relatively smaller differences among Japanese beans. This result shows that trace-elements bring us some practical information of the region where the product grown.

Fish gelatin thin film standards for biological application of PIXE

NASA Astrophysics Data System (ADS)

Manuel, Jack E.; Rout, Bibhudutta; Szilasi, Szabolcs Z.; Bohara, Gyanendra; Deaton, James; Luyombya, Henry; Briski, Karen P.; Glass, Gary A.

2014-08-01

There exists a critical need to understand the flow and accumulation of metallic ions, both naturally occurring and those introduced to biological systems. In this paper the results of fabricating thin film elemental biological standards containing nearly any combination of trace elements in a protein matrix are presented. Because it is capable of high elemental sensitivity, particle induced X-ray emission spectrometry (PIXE) is an excellent candidate for in situ analysis of biological tissues. Additionally, the utilization of microbeam PIXE allows the determination of elemental concentrations in and around biological cells. However, obtaining elemental reference standards with the same matrix constituents as brain tissue is difficult. An excellent choice for simulating brain-like tissue is Norland® photoengraving glue which is derived from fish skin. Fish glue is water soluble, liquid at room temperature, and resistant to dilute acid. It can also be formed into a thin membrane which dries into a durable, self-supporting film. Elements of interest are introduced to the fish glue in precise volumetric additions of well quantified atomic absorption standard solutions. In this study GeoPIXE analysis package is used to quantify elements intrinsic to the fish glue as well as trace amounts of manganese added to the sample. Elastic (non-Rutherford) backscattered spectroscopy (EBS) and the 1.734 MeV proton-on-carbon 12C(p,p)12C resonance is used for a normalization scheme of the PIXE spectra to account for any discrepancies in X-ray production arising from thickness variation of the prepared standards. It is demonstrated that greater additions of the atomic absorption standard cause a viscosity reduction of the liquid fish glue resulting in thinner films but the film thickness can be monitored by using simultaneous PIXE and EBS proton data acquisition.

Comparative trace elemental analysis of cancerous and non-cancerous tissues of rectal cancer patients using PIXE

NASA Astrophysics Data System (ADS)

Naga Raju, G. J.; Sarita, P.; Murthy, K. S. R.

2017-08-01

Particle Induced X-ray Emission (PIXE), an accelerator based analytical technique has been employed in this work for the analysis of trace elements in the cancerous and non-cancerous tissues of rectal cancer patients. A beam of 3 MeV protons generated from 3 MV Pelletron accelerator at the Ion Beam Laboratory of Institute of Physics, Bhubaneswar, India was used as projectile to excite the atoms present in the tissues samples. PIXE technique, with its capability to detect simultaneously several elements present at very low concentrations, offers an excellent tool for trace element analysis. The characteristic X-rays emitted by the samples were recorded by a high resolution Si (Li) detector. On the basis of the PIXE spectrum obtained for each sample, the elements Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, and Br were identified and their relative concentrations were estimated in the cancerous and non-cancerous tissues of rectum. The levels of Mn, Fe, Co, Cu, Zn, and As were higher (p < 0.005) while the levels of Ca, Cr and Ni were lower (p < 0.005) in the cancer tissues relative to the normal tissues. The alterations in the levels of the trace elements observed in the present work are discussed in this paper with respect to their potential role in the initiation, promotion and inhibition of cancer of the rectum.

Characterization and application of automated in-vacuum PIXE/EBS system for direct analysis of chloride and sulfate ions attack in cementitious materials

NASA Astrophysics Data System (ADS)

Rihawy, M. S.; Alwazzeh, M.; Abbas, K.

2018-01-01

Ion beam analysis (IBA) techniques (Particle Induced X-ray Emission, PIXE and Elastic Backscattering Spectrometry, EBS), were applied to investigate chloride and sulfate ions diffusion into laboratory prepared mortar samples. Development and characterization of an automated in-vacuum macro PIXE/EBS system is thoroughly discussed. Depth profile information of both chloride and sulfate ions in laboratory prepared mortar samples, after immersion in sea water for nine months, was rapidly and easily obtained at fairly low cost and with standardless analysis, demonstrating the value of the application of IBA to elemental depth profiling in cementitious materials. Chloride and sulfate depth profiles were obtained for two sets of mortar samples, one prepared with different water/cement (W/C) ratios and the other with different sand/cement (S/C) ratios. Results showed higher diffusion rates of both chloride and sulfate ions when both ratios are increased. Additionally, the W/C ratio has a stronger influence in both sulfate and chloride penetration than the S/C ratio, and chloride ions penetrate faster than sulfates. Advantages and limitations of applying IBA techniques in this investigation are discussed. The comparison between PIXE and other X-ray based analytical techniques, namely X-ray fluorescence (XRF) and energy and wavelength dispersive X-rays (EDX/WDX), as well as other traditional wet chemical methods is reviewed, and industrial applications are discussed.

VIBA-Lab 3.0: Computer program for simulation and semi-quantitative analysis of PIXE and RBS spectra and 2D elemental maps

NASA Astrophysics Data System (ADS)

Orlić, Ivica; Mekterović, Darko; Mekterović, Igor; Ivošević, Tatjana

2015-11-01

VIBA-Lab is a computer program originally developed by the author and co-workers at the National University of Singapore (NUS) as an interactive software package for simulation of Particle Induced X-ray Emission and Rutherford Backscattering Spectra. The original program is redeveloped to a VIBA-Lab 3.0 in which the user can perform semi-quantitative analysis by comparing simulated and measured spectra as well as simulate 2D elemental maps for a given 3D sample composition. The latest version has a new and more versatile user interface. It also has the latest data set of fundamental parameters such as Coster-Kronig transition rates, fluorescence yields, mass absorption coefficients and ionization cross sections for K and L lines in a wider energy range than the original program. Our short-term plan is to introduce routine for quantitative analysis for multiple PIXE and XRF excitations. VIBA-Lab is an excellent teaching tool for students and researchers in using PIXE and RBS techniques. At the same time the program helps when planning an experiment and when optimizing experimental parameters such as incident ions, their energy, detector specifications, filters, geometry, etc. By "running" a virtual experiment the user can test various scenarios until the optimal PIXE and BS spectra are obtained and in this way save a lot of expensive machine time.

MeV ion-beam analysis of optical data storage films

NASA Technical Reports Server (NTRS)

Leavitt, J. A.; Mcintyre, L. C., Jr.; Lin, Z.

1993-01-01

Our objectives are threefold: (1) to accurately characterize optical data storage films by MeV ion-beam analysis (IBA) for ODSC collaborators; (2) to develop new and/or improved analysis techniques; and (3) to expand the capabilities of the IBA facility itself. Using H-1(+), He-4(+), and N-15(++) ion beams in the 1.5 MeV to 10 MeV energy range from a 5.5 MV Van de Graaff accelerator, film thickness (in atoms/sq cm), stoichiometry, impurity concentration profiles, and crystalline structure were determined by Rutherford backscattering (RBS), high-energy backscattering, channeling, nuclear reaction analysis (NRA) and proton induced X-ray emission (PIXE). Most of these techniques are discussed in detail in the ODSC Annual Report (February 17, 1987), p. 74. The PIXE technique is briefly discussed in the ODSC Annual Report (March 15, 1991), p. 23.

Evaluation of specimen preparation techniques for micro-PIXE localisation of elements in hyperaccumulating plants

NASA Astrophysics Data System (ADS)

Kachenko, Anthony G.; Siegele, Rainer; Bhatia, Naveen P.; Singh, Balwant; Ionescu, Mihail

2008-04-01

Hybanthus floribundus subsp. floribundus, a rare Australian Ni-hyperaccumulating shrub and Pityrogramma calomelanos var. austroamericana, an Australian naturalized As-hyperaccumulating fern are promising species for use in phytoremediation of contaminated sites. Micro-proton-induced X-ray emission (μ-PIXE) spectroscopy was used to map the elemental distribution of the accumulated metal(loid)s, Ca and K in leaf or pinnule tissues of the two plant species. Samples were prepared by two contrasting specimen preparation techniques: freeze-substitution in tetrahydrofuran (THF) and freeze-drying. The specimens were analysed to compare the suitability of each technique in preserving (i) the spatial elemental distribution and (ii) the tissue structure of the specimens. Further, the μ-PIXE results were compared with concentration of elements in the bulk tissue obtained by ICP-AES analysis. In H. floribundus subsp. floribundus, μ-PIXE analysis revealed Ni, Ca and K concentrations in freeze-dried leaf tissues were at par with bulk tissue concentrations. Elemental distribution maps illustrated that Ni was preferentially localised in the adaxial epidermal tissues (1% DW) and least concentration was found in spongy mesophyll tissues (0.53% DW). Conversely, elemental distribution maps of THF freeze-substituted tissues indicated significantly lower Ni, Ca and K concentrations than freeze-dried specimens and bulk tissue concentrations. Moreover, Ni concentrations were uniform across the whole specimen and no localisation was observed. In P. calomelanos var. austroamericana freeze-dried pinnule tissues, μ-PIXE revealed statistically similar As, Ca and K concentrations as compared to bulk tissue concentrations. Elemental distribution maps showed that As localisation was relatively uniform across the whole specimen. Once again, THF freeze-substituted tissues revealed a significant loss of As compared to freeze-dried specimens and the concentrations obtained by bulk tissue analysis. The results demonstrate that freeze-drying is a suitable sample preparation technique to study elemental distribution of ions in H. floribundus and P. calomelanos plant tissues using μ-PIXE spectroscopy. Furthermore, cellular structure was preserved in samples prepared using this technique.

PIXE and PGAA - Complementary methods for studies on ancient glass artefacts (from Byzantine, late medieval to modern Murano glass)

NASA Astrophysics Data System (ADS)

Constantinescu, Bogdan; Cristea-Stan, Daniela; Szőkefalvi-Nagy, Zoltán; Kovács, Imre; Harsányi, Ildikó; Kasztovszky, Zsolt

2018-02-01

Combined external milli-beam Particle Induced X-ray Emission (PIXE) and Prompt Gamma Activation Analysis (PGAA) analysis was applied to characterize the composition of paste and colorants from some fragments of Byzantine bracelets (10th-12th Centuries AD), late medieval (17th-18th Centuries AD) and modern Murano glass pieces. As fluxes, PGAA revealed the samples are soda-lime glass, except four samples - two medieval vessel white shards and two dark Byzantine fragments of bracelets - which have potash flux. Aluminium was detected in various proportions in all samples indicating different sources for the added sand. The presence of Magnesium is relevant only in one bracelet fragment suggesting the use of plant (wood?) ash and confirming that the Byzantine bracelet is manufactured from the mixture of both types of glass (natron and plant ash based). PGAA also indicated the presence of low quantities of Cadmium, high level of Arsenic and Lead (possibly lead arsenate) in one medieval sample and of ZnO in Murano glass, and of CoO traces (maximum 0.1%) in all blue-colored Byzantine, late medieval to modern Murano glass artefacts. PIXE confirmed the use of small quantities of CoO for blue color, indicated Manganese combined with Iron for dark glass, Copper for green, Lead, Tin and an Arsenic compound (orpiment?) for yellow and in the case of modern Murano glass Selenium and Cadmium to obtain a reddish color. Despite PIXE - PIGE combination is probably the best one for glass analysis, our external milli-PIXE - PGAA methods proved to be adequate complementary tools to determine many chemical elements from glass composition - Si, Na, K, Ca, Al, Mg, various metallic oxides.

Standardization of proton-induced x-ray emission technique for analysis of thick samples

NASA Astrophysics Data System (ADS)

Ali, Shad; Zeb, Johar; Ahad, Abdul; Ahmad, Ishfaq; Haneef, M.; Akbar, Jehan

2015-09-01

This paper describes the standardization of the proton-induced x-ray emission (PIXE) technique for finding the elemental composition of thick samples. For the standardization, three different samples of standard reference materials (SRMs) were analyzed using this technique and the data were compared with the already known data of these certified SRMs. These samples were selected in order to cover the maximum range of elements in the periodic table. Each sample was irradiated for three different values of collected beam charges at three different times. A proton beam of 2.57 MeV obtained using 5UDH-II Pelletron accelerator was used for excitation of x-rays from the sample. The acquired experimental data were analyzed using the GUPIXWIN software. The results show that the SRM data and the data obtained using the PIXE technique are in good agreement.

PIXE-PIGE analysis of teeth from children with and without cystic fibrosis

NASA Astrophysics Data System (ADS)

Cua, Florence T.

1990-04-01

Proton-induced X-ray emission (PIXE) and proton-induced gamma emission (PIGE) were used to analyze Ca, Sr, Fe, Zn, Cu and F, Na, P, Mg respectively in teeth of children with and without cystic fibrosis. The accelerators used were the 3 MeV proton Van de Graaff accelerator at the Brookhaven National Laboratory, NY, USA for the first run and the 8 MV FN-tandem Van de Graaff accelerator at the Nuclear Physics Laboratory, Rutgers University, NJ, USA producing a 4 MeV proton beam for the second and third run. Description of the experimental setup, and the data acquisition system are described in the text. A summary of the results on element concentration as a function of types of teeth and correlation studies are in the text and in F.T. Cua, Ph.D. Thesis, Rutgers Univ. (1989).

PIXE analysis of mineral matter in thin sections of human lung

NASA Astrophysics Data System (ADS)

Annegarn, H. J.; Pillay, A. E.; Da Vies, J. C. A.; Faure, D.; Sellschop, J. P. F.

1988-12-01

It is postulated that insoluble mineral residues in the lungs of deceased miners may provide a quantitative measure of the integrated lifetime dust exposure. For epidemiological surveys rapid instrumental techniques are required to analyse representative samples of lung tissue. Particle-induced X-ray emission (PIXE) has been evaluated for analysis of microtomed slices of wax-embedded lung and lymph node (Hilar gland) tissue from deceased miners. The 50 μm slices, mounted on Mylar backings and placed in a He atmosphere, were irradiated using 3.2 MeV protons. PIXE analysis provided adequate sensitivity for key mineral elements including Si, Cr and Ti. The porous, nonuniform nature of lung tissue made it impossible to measure the tissue mass in the irradiated area, preventing the calculation of mass concentrations. Instead, biological sulphur was used as an internal standard, assuming that the fraction of S in soft, fat-free tissue is constant. Results are presented for lung and lymph node tissue from gold, chrome, copper, platinum and asbestos miners. Si mineral residues in lymph node tissue were found to be concentrated by a factor 50 relative to lung. Cr residues were clearly observed in the chrome miner's lung, but no excess of Cu was present in the copper miner's lung. There is evidence of preferential Si removal relative to Ti. Results warrant further development of PIXE for scanning of large numbers of lung samples prepared in the above manner.

Analysis of memory consolidation and evocation in rats by proton induced X-ray emission

NASA Astrophysics Data System (ADS)

Jobim, P. F. C.; dos Santos, C. E. I.; Maurmann, N.; Reolon, G. K.; Debastiani, R.; Pedroso, T. R.; Carvalho, L. M.; Dias, J. F.

2014-08-01

It is well known that trace elements such as Mg, Ca, Fe, Cu and Zn have a key role in synapse plasticity and learning. Learning process is conventionally divided in three distinct and complementary stages: memory acquisition, consolidation and evocation. Consolidation is the stabilization of the synaptic trace formed by acquisition, while evocation is the recall of this trace. Ion-based techniques capable of providing information concerning the elemental composition of organic tissues may be helpful to improve our understanding on memory consolidation and evocation processes. In particular, the Particle-Induced X-ray Emission (PIXE) technique can be used to analyze different biological tissues with good accuracy. In this work we explore the versatility of PIXE to measure the elemental concentrations in rat brain tissues in order to establish any possible correlation between them and the memory consolidation and evocation processes. To this end, six groups of middle-age male Wistar rats were trained and tested in a step-down Inhibitory Avoidance conditioning. After the behavior tests, the animals were decapitated in accordance with the legal procedures and their brains were removed and dissected for the PIXE analyses. The results demonstrated that there are differences in the elemental concentration among the groups and such variations may be associated with their availability to the learning processes (by memory consolidation and evocation). Moreover, the control groups circumvent the possibility that a non-specific event involved in learning tasks cause such variations. Our results suggest that PIXE may be a useful tool to investigate memory consolidation and evocation in animal models.

PROCEEDINGS ON SYNCHROTRON RADIATION: Transfer characterization of sulfur from coal-burning emission to plant leaves by PIXE and XANES

NASA Astrophysics Data System (ADS)

Bao, Liang-Man; Zhang, Gui-Lin; Zhang, Yuan-Xim; Li, Yan; Lin, Jun; Liu, Wei; Cao, Qing-Chen; Zhao, Yi-Dong; Ma, Chen-Yan; Han, Yong

2009-11-01

The impact of coal-burning emission on sulfur in camphor leaves was investigated using Proton Induced X-ray Emission (PIXE) and synchrotron radiation technique X-ray Absorption Near-Edge Structure (XANES) spectroscopy. The PIXE results show that the sulfur concentrations in the leaves collected at the polluted site are significantly higher than those in controls. The Sulfur XANES spectra show the presence of organic (disulfides, thiols, thioethers, sulfonates and sulfoxides) and inorganic sulfur (sulfates) in the leaves. The inorganic sulfur in the leaves of camphor tree polluted by coal combustion is 15% more than that of the control site. The results suggest that the long-term coal-burning pollution resulted in an enhanced content of the total sulfur and sulfate in the leaves, and the uptake of sulfur by leaves had exceeded the metabolic requirement of plants and the excess of sulfur was stored as SO2-4. It can monitor the sulfur pollution in atmosphere.

Micro-PIXE mapping of mineral distribution in mature grain of two pearl millet cultivars

NASA Astrophysics Data System (ADS)

Minnis-Ndimba, R.; Kruger, J.; Taylor, J. R. N.; Mtshali, C.; Pineda-Vargas, C. A.

2015-11-01

Micro-proton-induced X-ray emission (micro-PIXE) was used to map the distribution of several nutritionally important minerals found in the grain tissue of two cultivars of pearl millet (Pennisetum glaucum (L.) R. Br.). The distribution maps revealed that the predominant localisation of minerals was within the germ (consisting of the scutellum and embryo) and the outer grain layers (specifically the pericarp and aleurone); whilst the bulk of the endosperm tissue featured relatively low concentrations of the surveyed minerals. Within the germ, the scutellum was revealed as a major storage tissue for P and K, whilst Ca, Mn and Zn were more prominent within the embryo. Fe was revealed to have a distinctive distribution pattern, confined to the dorsal end of the scutellum; but was also highly concentrated in the outer grain layers. Interestingly, the hilar region was also revealed as a site of high accumulation of minerals, particularly for S, Ca, Mn, Fe and Zn, which may be part of a defensive strategy against infection or damage. Differences between the two cultivars, in terms of the bulk Fe and P content obtained via inductively coupled plasma optical emission spectrometry (ICP-OES), concurred with the average concentration data determined from the analysis of micro-PIXE spectra specifically extracted from the endosperm tissue.

Source apportionment by PMF on elemental concentrations obtained by PIXE analysis of PM10 samples collected at the vicinity of lignite power plants and mines in Megalopolis, Greece

NASA Astrophysics Data System (ADS)

Manousakas, M.; Diapouli, E.; Papaefthymiou, H.; Migliori, A.; Karydas, A. G.; Padilla-Alvarez, R.; Bogovac, M.; Kaiser, R. B.; Jaksic, M.; Bogdanovic-Radovic, I.; Eleftheriadis, K.

2015-04-01

Particulate matter (PM) is an important constituent of atmospheric pollution especially in areas under the influence of industrial emissions. Megalopolis is a small city of 10,000 inhabitants located in central Peloponnese in close proximity to three coal opencast mines and two lignite fired power plants. 50 PM10 samples were collected in Megalopolis during the years 2009-11 for elemental and multivariate analysis. For the elemental analysis PIXE was used as one of the most effective techniques in APM analytical characterization. Altogether, the concentrations of 22 elements (Z = 11-33), whereas Black Carbon was also determined for each sample using a reflectometer. Factorization software was used (EPA PMF 3.0) for source apportionment analysis. The analysis revealed that major emission sources were soil dust 33% (7.94 ± 0.27 μg/m3), biomass burning 19% (4.43 ± 0.27 μg/m3), road dust 15% (3.63 ± 0.37 μg/m3), power plant emissions 13% (3.01 ± 0.44 μg/m3), traffic 12% (2.82 ± 0.37 μg/m3), and sea spray 8% (1.99 ± 0.41 μg/m3). Wind trajectories have suggested that metals associated with emission from the power plants came mainly from west and were connected with the locations of the lignite mines located in this area. Soil resuspension, road dust and power plant emissions increased during the warm season of the year, while traffic/secondary, sea spray and biomass burning become dominant during the cold season.

Using ICP and micro-PIXE to investigate possible differences in the mineral composition of genetically modified versus wild-type sorghum grain

NASA Astrophysics Data System (ADS)

Ndimba, R.; Cloete, K.; Mehlo, L.; Kossmann, J.; Mtshali, C.; Pineda-Vargas, C.

2017-08-01

In the present study, possible differences in the mineral composition of transgenic versus non-transgenic sorghum grains were investigated using inductively coupled atomic emission spectroscopy (ICP-AES); and, in-tissue elemental mapping by micro Proton-Induced X-ray Emission (micro-PIXE) analysis. ICP AES was used to analyse the bulk mineral content of the wholegrain flour derived from each genotype; whilst micro-PIXE was used to interrogate localised differences in mineral composition specific to certain areas of the grain, such as the bran layer and the central endosperm tissue. According to the results obtained, no significant difference in the average Fe, Zn or Ca content was found to differentiate the transgenic from the wild-type grain using ICP-AES. However, using micro-PIXE, a significant reduction in zinc could be detected in the bran layer of the transgenic grains relative to wild-type. Although it is difficult to draw firm conclusions, as a result of the small sample size used in this study, micro-PIXE has nonetheless proven itself as a useful technique for highlighting the possibility that there may be reduced levels of zinc accumulation in the bran layer of the transgenic grains. Given that the genetic modification targets proteins that are highly concentrated in certain parts of the bran tissue, it seems plausible that the reduced levels of zinc may be an unintended consequence of the silencing of kafirin proteins. Although no immediate health or nutritional concerns emerge from this preliminary finding, it is noted that zinc plays an important biological role within this part of the grain as a structural stabiliser and antioxidant factor. Further study is therefore needed to assess more definitively the extent of the apparent localised reduction in zinc in the transgenic grains and how this may affect other important grain quality characteristics.

Element-based prognostics of occupational pneumoconiosis using micro-proton-induced X-ray emission analysis.

PubMed

He, Xiaodong; Shen, Hao; Chen, Zidan; Rong, Caicai; Ren, Minqin; Hou, Likun; Wu, Chunyan; Mao, Ling; Lu, Quan; Su, Bo

2017-12-01

Pneumoconiosis is an occupational disease accompanied by long-term lung impairment, for which prediction of prognosis is poorly understood because of the complexity of the inhaled particles. Micro-proton-induced X-ray emission (micro-PIXE) analysis, which is advantageous for high-sensitivity, two-dimensional element mapping of lung tissues, was used to investigate element-based predictive factors of prognosis in Chinese patients with welder's and coal miner's pneumoconiosis. Chest radiographs and lung function tests showed that most of the coal miners deteriorated, whereas symptoms in some welders were alleviated after 5 yr, as determined by comparing percent vital capacity (%VC) and forced expiratory volume in the 1st second over forced vital capacity (FEV1.0/FVC) to values taken at the initial diagnosis. Micro-PIXE analysis suggested that the most abundant particulates in welder's pneumoconiosis were Fe, Mn, and Ti (metallic oxide),which were accompanied by particulates containing Si, Al, and Ca (aluminum silicate) or only Si (SiO 2 ); the most abundant particulates in coal miner's pneumoconiosis were composed of C, Si, Al, K, and Ti, which were accompanied by particulates containing Ca or Fe. Particulates containing Al, Si, S, K, Ca, and Ti (orthoclase and anorthite) were correlated with severity of fibrosis. Multivariable linear regression suggested that long-term FEV1.0/FVC decrease was independently associated with Si and smoking index, whereas %VC decrease was associated with Si and Ti. A risk index comprised of these factors was developed to predict the prognosis of pneumoconiosis. Micro-PIXE analysis is feasible for the evaluation of elemental composition and dust exposure, especially for patients whose exposure is mixed or uncertain. Copyright © 2017 the American Physiological Society.

The Importance of Particle Induced X-Ray Emission (PIXE) Analysis and Imaging to the Search for Life on the Ocean Worlds

NASA Technical Reports Server (NTRS)

Blake, D. F.; Sarrazin, P.; Thompson, Kathleen

2017-01-01

The MapX imaging X-ray spectrometer is described and Monte Carlo modeling is used to show the efficacy of 244-Cm radioisotope sources in detecting and quantifying the biogenic elements in ices on Ocean Worlds such as Europa.

Micro-PIXE characterisation of uranium occurrence in the coal zones and the mudstones of the Springbok Flats Basin, South Africa

NASA Astrophysics Data System (ADS)

Nxumalo, V.; Kramers, J.; Mongwaketsi, N.; Przybyłowicz, W. J.

2017-08-01

Uranium occurrence and characterisation in the coal samples of the upper coal zones of the Vryheid Formation and mudstones of the Volksrust Formation was investigated using micro-PIXE (Proton-Induced X-ray Emission) and proton backscattering spectrometry (BS) in conjunction with the nuclear microprobe. Two styles of uranium mineralisation in the Springbok Flats Basin were found: syngenetic mineralisation in which uranium occurs organically bound with coal matrix, with no discrete uranium minerals formed, and epigenetic mineralisation in which uranium occurs in veins that are filled with coffinite with botryoidal texture in the mudstones of the Volksrust Formation, overlying the coal zones. Micro-PIXE analysis made it possible to map out trace elements (including uranium) associated with the coals at low levels of detection, which other techniques such as SEM-EDS and ore microscopy failed. This information will help in better understanding of the best extraction methods to be employed to recover uranium from the coals of the Springbok Flats Basin.

Evaluation of caries progression in dentin treated by fluoride-containing materials using an in-air micro-PIGE and micro-PIXE measurement system

NASA Astrophysics Data System (ADS)

Yamamoto, H.; Iwami, Y.; Yagi, K.; Hayashi, M.; Komatsu, H.; Okuyama, K.; Matsuda, Y.; Yasuda, K.

2015-04-01

It is well-known that fluorine (F) is involved in the progression of caries. The evaluation of caries progression has conventionally been based on the change in mineral content using transverse microradiography (TMR). The purpose of this study was to evaluate the progression of dentinal caries by the change in calcium (Ca) content using Particle-Induced Gamma-ray Emission/Particle-Induced X-ray Emission (PIGE/PIXE) techniques at the Wakasa Wan Energy Research Center. We also assessed the relationship between caries progression rate and the concentration of F penetration into dentin from dental fluoride-containing materials (FCMs). Dentin sections of six extracted human teeth were prepared to obtain various amounts of F uptake using three types of FCMs. F and Ca distribution of specimens were obtained using PIGE/PIXE techniques. After evaluation, the specimens were immersed in 10 ml of demineralizing solution (pH 4.5) to simulate caries attack. To estimate caries progression rates, the same portions of the specimens were evaluated after caries attack treatment using PIGE/PIXE. A negative correlation between the F uptake in dentin and the rate of caries progression was observed. Therefore, caries progression in dentin was reduced by increasing the amount of F uptake from FCMs. This demonstrates that PIGE/PIXE techniques are valuable for estimating caries progression rates.

A new small-footprint external-beam PIXE facility for cultural heritage applications using pulsed proton beams

NASA Astrophysics Data System (ADS)

Vadrucci, M.; Bazzano, G.; Borgognoni, F.; Chiari, M.; Mazzinghi, A.; Picardi, L.; Ronsivalle, C.; Ruberto, C.; Taccetti, F.

2017-09-01

In the framework of the COBRA project, elemental analyses of cultural heritage objects based on the particle induced X-ray emission (PIXE) are planned in a collaboration between the APAM laboratory of ENEA-Frascati and the LABEC laboratory of INFN in Florence. With this aim a 3-7 MeV pulsed proton beam, driven by the injector of the protontherapy accelerator under construction for the TOP-IMPLART project, will be used to demonstrate the feasibility of the technique with a small-footprint pulsed accelerator to Italian small and medium enterprises interested in the composition analysis of ancient artifacts. The experimental set-up for PIXE analysis on the TOP-IMPLART machine consists of a modified assembly of the vertical beam line usually dedicated to radiobiology experiments: the beam produced by the injector (RFQ + DTL, a PL7 ACCSYSHITACHI model) is bent to 90° by a magnet, is collimated by a 300 μm aperture inserted in the end nozzle and extracted into ambient pressure by an exit window consisting of a Upilex foil 7.5 μm thick. The beam is pulsed with a variable pulse duration of 20-100 μs and a repetition rate variable from 10 to 100 Hz. The X-ray detection system is based on a Ketek Silicon Drift Detector (SDD) with 7 mm2 active area and 450 μm thickness, with a thin Beryllium entrance window (8 μm). The results of the calibration of this new PIXE set-up using thick target standards and of the analysis of the preliminary measurements on pigments are presented.

External-RBS, PIXE and NRA analysis for ancient swords

NASA Astrophysics Data System (ADS)

Santos, Hellen C.; Added, Nemitala; Silva, Tiago F.; Rodrigues, C. L.

2015-02-01

Elemental composition of the steel of two ancient swords (Japanese and Damascus from a private collection) was characterized using in air IBA techniques. Our results contribute for the understanding the processes of manufacturing (hammering and quenching) and surface treatments applied in these swords. The Particle Induced X-ray Emission (PIXE) measurements along the Damascus blade allowed to identify and to trace a superficial concentration profile for the elements such Cr, Mn, Fe, Ni, Cu, Zn and As, while results for the Japanese blade showed only the presence of iron. The carbon content on the surface was also investigated using a resonant region in the Elastic Backscattering Spectrometry (EBS) measurements and the results have shown a slightly difference between the surfaces under investigation. In order to investigate the nitrogen content on surface, that could explain the hardening process, we used Nuclear Reaction Analysis (NRA) and the results shown that nitrogen content was under our detection limit for the technique (0.3% in mass). The measurements of PIXE, NRA and EBS were taken using the external beam setup installed at Lamfi - São Paulo/Brazil, the latter being successfully implemented for the first time in this facility.

Surface analysis of space telescope material specimens

NASA Technical Reports Server (NTRS)

Fromhold, A. T.; Daneshvar, K.

1985-01-01

Qualitative and quantitative data on Space Telescope materials which were exposed to low Earth orbital atomic oxygen in a controlled experiment during the 41-G (STS-17) mission were obtained utilizing the experimental techniques of Rutherford backscattering (RBS), particle induced X-ray emission (PIXE), and ellipsometry (ELL). The techniques employed were chosen with a view towards appropriateness for the sample in question, after consultation with NASA scientific personnel who provided the material specimens. A group of eight samples and their controls selected by NASA scientists were measured before and after flight. Information reported herein include specimen surface characterization by ellipsometry techniques, a determination of the thickness of the evaporated metal specimens by RBS, and a determination of trace impurity species present on and within the surface by PIXE.

Ion beam analysis of rubies and their simulants

NASA Astrophysics Data System (ADS)

Juncomma, U.; Intarasiri, S.; Bootkul, D.; Tippawan, U.

2014-07-01

Ion beam analysis (IBA) is a set of well known powerful analytical techniques which use energetic particle beam as a probe. Among them, two techniques are suitable for gemological analysis, i.e., Particle Induced X-rays Emission (PIXE) and Ionoluminescence (IL). We combine these two techniques for the investigations of rubies and their simulants. The main objective is to find a reference fingerprint of these gemstones. The data are collected from several natural rubies, synthetic rubies, red spinels, almandine garnets and rubellite which very much resemble and are difficult to distinguish with the gemologist loupe. From our measurements, due to their different crystal structures and compositions, can be clearly distinguished by the IL and PIXE techniques. The results show that the PIXE spectra consist of a few dominant lines of the host matrix elements of each gemstone and some weaker lines due to trace elements of transition metals. PIXE can easily differentiate rubies from other stones by evaluating their chemical compositions. It is noticed that synthetic rubies generally contain fewer impurities, lower iron and higher chromium than the natural ones. Moreover, the IL spectrum of ruby is unique and different from those of others stones. The typical spectrum of ruby is centered at 694 nm, with small sidebands that can be ascribed to a Cr3+ emission spectrum which is dominated by an R-line at the extreme red end of the visible part of the electromagnetic spectrum. Although the spectrum of synthetic ruby is centered at the same wavelength, the peak is stronger due to higher concentration of Cr and lower concentration of Fe than for natural rubies. For spinel, the IL spectrum shows strong deformation where the R-line is split due to the presence of MgO. For rubellite, the peak center is shifted to 692 nm which might be caused by the replacement of Mn3+ at the Al3+ site of the host structure. It is noticed that almandine garnet is not luminescent due to the idiochromatic nature of the stone.

Use of different spectroscopic techniques in the analysis of Roman age wall paintings.

PubMed

Agnoli, Francesca; Calliari, Irene; Mazzocchin, Gian-Antonio

2007-01-01

In this paper the analysis of samples of Roman age wall paintings coming from: Pordenone, Vicenza and Verona is carried out by using three different techniques: energy dispersive x-rays spectroscopy (EDS), x-rays fluorescence (XRF) and proton induced x-rays emission (PIXE). The features of the three spectroscopic techniques in the analysis of samples of archaeological interest are discussed. The studied pigments were: cinnabar, yellow ochre, green earth, Egyptian blue and carbon black.

Study of new sheep bone and Zn/Ca ratio around TiAlV screw: PIXE RBS analysis

NASA Astrophysics Data System (ADS)

Guibert, G.; Munnik, F.; Langhoff, J. D.; Von Rechenberg, B.; Buffat, Ph. A.; Laub, D.; Faber, L.; Ducret, F.; Gerber, I.; Mikhailov, S.

2008-03-01

This study reports on in vivo particle induced X-ray emission (PIXE) measurements combined with Rutherford backscattering spectroscopy (RBS) analyses of new remodeled sheep bone formed around TiAlV screws. The implants (screws) were anodized by a modified TiMax™ process. The interface between the implant and the bone was carefully investigated. [Zn]/[Ca] in-depth composition profiles as well as Ca, Fe elemental maps were recorded. The thickness of new bone formed around the screw reached 300-400 μm. Osteon and Osteoid phases were identified in the new bone. A higher [Zn]/[Ca] ratio was observed in the new bone as compared to the mature bone. Blood vessels were observed in the bone in close contact with the screw. This study shows the potential of ion beam analysis for biological and biomedical characterization.

Scanning proton microprobe applied to analysis of individual aerosol particles from Amazon Basin

NASA Astrophysics Data System (ADS)

Gerab, Fábio; Artaxo, Paulo; Swietlicki, Erik; Pallon, Jan

1998-03-01

The development of the Scanning Proton Microprobe (SPM) offers a new possibility for individual aerosol particle studies. The SPM joins Particle Induced X-ray Emission (PIXE) elemental analysis qualities with micrometric spatial resolution. In this work the Lund University SPM facility was used for elemental characterization of individual aerosol particles emitted to the atmosphere in the Brazilian Amazon Basin, during gold mining activities by the so-called "gold shops".

Mutational And Structural Studies Of The PixD BLUF Output Signal That Affects Light-Regulated Interactions With PixE

PubMed Central

Yuan, Hua; Dragnea, Vladimira; Wu, Qiong; Gardner, Kevin H.; Bauer, Carl E.

2011-01-01

PixD (Slr1694) is a BLUF (blue-light using FAD) photoreceptor used by the cyanobacterium Synechocystis sp. PCC6803 to control phototaxis toward blue light. In this study we probe the involvement of a conserved Tyr8-Gln50-Met93 triad in promoting an output signal upon blue light excitation of the bound flavin. Analysis of acrylamide quenching of Trp91 fluorescence shows that the side chain of this residue remains partially solvent exposed in both the lit and dark states. Mutational analysis demonstrates that substitution mutations at Tyr8 and Gln50 result in the loss of the photocycle while a mutation of Met93 does not appreciably disturb the formation of the light excited state and only minimally accelerates its decay from 5.7 s to 4.5 s. However, mutations in Tyr8, Gln50 and Met93 disrupt the ability of PixD dimers to interact with PixE to form a higher ordered PixD10-PixE5 complex, which is indicative of a lit conformational state. Solution NMR spectroscopy and X-ray crystallographic analyses confirm that a Tyr8 to Phe mutation is locked in a pseudo light excited state revealing flexible areas in PixD that likely constitute part of an output signal upon light excitation of wild type PixD. PMID:21688827

Leaf elemental analysis in mycorrhizal post oak seedlings

NASA Astrophysics Data System (ADS)

Boling, B. C.; Naab, F. U.; Smith, D.; Duggan, J. L.; McDaniel, F. D.

2006-09-01

Growth and element assimilation was investigated in the leaves of post oak seedlings exposed to four different treatment combinations of fertilization and ectomycorrhizal inoculation. Element concentration was analyzed via particle-induced X-ray emission spectrometry (PIXE). PIXE detected 10 of the 13 essential macro and micronutrients: P, S, Mg, Ca, K, Cu, Zn, Mn, Fe and Cl. Mean growth and dry weight was significantly different across the treatment groups as well as the mean concentration of Mg, Al, S, K, Ca, Fe, Cu and Zn. The data suggest that fertilization rather than mycorrhizal inoculation had a stronger influence on nutrient uptake. This study is the first to analyze element concentration in post oak and to investigate the potential benefits of mycorrhizal symbiosis in post oak seedlings in terms of nutrient uptake.

Towards the differentiation of non-treated and treated corundum minerals by ion-beam-induced luminescence and other complementary techniques.

PubMed

Calvo del Castillo, H; Deprez, N; Dupuis, T; Mathis, F; Deneckere, A; Vandenabeele, P; Calderón, T; Strivay, D

2009-06-01

Differentiation of treated and non-treated gemstones is a chief concern for major jewellery import companies. Low-quality corundum specimens coming from Asia appear to be often treated with heat, BeO or flux in order to enhance their properties as precious minerals. A set of corundum samples, rubies and sapphires from different origins, both treated and non-treated has been analysed at the Centre Européen d'Archéométrie, with ion-beam-induced luminescence (IBIL) and other complementary techniques such as Raman, proton-induced X-ray emission (PIXE), and proton-induced gamma-ray emission (PIGE). IBIL, also known as ionoluminescence, has been used before to detect impurities or defects inside synthetic materials and natural minerals; its use for the discrimination of gemstone simulants or synthetic analogues has been elsewhere discussed (Cavenago-Bignami Moneta, Gemología, Tomo I Piedras preciosas, perlas, corales, marfil. Ediciones Omega, Barcelona, 1991). PIXE has been frequently applied in the archaeometric field for material characterisation and provenance studies of minerals (Hughes, Ruby & sapphire. RWH Publishing, Fallbrook, 1997; Calvo del Castillo et al., Anal Bioanal Chem 387:869-878, 2007; Calligaro et al., NIM-B 189:320-327, 2002) and PIGE complements the elemental analysis by detecting light elements in these materials such as-and lighter than-sodium that cannot be identified with the PIXE technique (Sanchez et al., NIM-B 130:682-686, 1997; Emmett et al., Gems Gemology 39:84-135, 2003). The micro-Raman technique has also been used complementarily to ion beam analysis techniques for mineral characterisation (Novak et al., Appl Surf Sci 231-232:917-920, 2004). The aim of this study is to provide new means for systematic analysis of corundum gemstone-quality mineral, alternative to the traditional gemmologic methods; for this purpose, a Spanish jewellery import company supplied us with a number of natural corundum samples coming from different places (part of them treated as explained above). The PIXE elemental concentrations of the samples showed large quantities of calcium and lead in some cases that can be linked to treatment with fluxes or lead oxide. The plot of the chromium and iron concentration grouped the samples in various aggregates that corresponded to the different types of corundum analysed. Micro-Raman complemented the PIXE analysis corroborating the presence of lead oxides but the use of the PIGE technique was not successful for the detection of beryllium due to the low cross section of the nuclear reaction chosen for its identification. IBIL was capable of distinguishing between treated and non-treated samples of the same type based on the luminescent features of the materials.

Characteristics of proton beams and secondary neutrons arising from two different beam nozzles

NASA Astrophysics Data System (ADS)

Choi, Yeon-Gyeong; Kim, Yu-Seok

2015-10-01

A tandem or a Van de Graaff accelerator with an energy of 3 MeV is typically used for Proton Induced X-ray Emission (PIXE) analysis. In this study, the beam line design used in the PIXE analysis, instead of the typical low-energy accelerator, was used to increase the production of isotopes from a 13-MeV cyclotron. For the PIXE analysis, the proton beam should be focused at the target through a nozzle after degrading the proton beams energy from 13 MeV to 3 MeV by using an energy degrader. Previous studies have been conducted to determine the most appropriate material for and the thickness of the energy degrader. From the energy distribution of the degraded proton beam and the neutron occurrence rate at the degrader, an aluminum nozzle of X thickness was determined to be the most appropriate nozzle construction. Neutrons are created by the collision of 3-MeV protons in the nozzle after passage through the energy degrader. In addition, a proton beam of sufficient intensity is required for a non-destructive PIXE analysis. Therefore, if nozzle design is to be optimized, the number of neutrons that arise from the collision of protons inside the nozzle, as well as the track direction of the generated secondary neutrons, must be considered, with the primary aim of ensuring that a sufficient number of protons pass through the nozzle as a direct beam. A number of laboratories are currently conducting research related to the design of nozzles used in accelerator fields, mostly medical fields. This paper presents a comparative analysis of two typical nozzle shapes in order to minimize the loss of protons and the generation of secondary neutrons. The neutron occurrence rate and the number of protons that pass through the nozzle were analyzed by using a Particle and Heavy Ion Transport code System (PHITS) program in order to identify the nozzle that generated the strongest proton beam.

Application of PIXE in the determination of the production cross section of a radionuclide decaying by electron capture

NASA Astrophysics Data System (ADS)

Morales, J. R.; Chesta, M. A.; Cancino, S. A.; Miranda, P. A.; Dinator, M. I.; Avila, M. J.

2005-01-01

Proton induced X-ray emission (PIXE) has been applied to the measurement of the production cross section of a radionuclide decaying by electron capture. By performing a PIXE type experiment on the daughter nuclide important advantages are obtained. The determination of some factors with usually large uncertainties, like solid angle and detector efficiency were avoided. The method was applied to the determination of cross section of the reaction 63Cu(d, p)64Cu at 2.4 MeV for 64Cu production. This result is in full agreement with that obtained through the decay of the 1346 keV gamma ray of 64Cu.

Proton Induced X-Ray Emission (PIXE) Analysis to Measure Trace Metals in Soil Along the East River in Queens, New York

NASA Astrophysics Data System (ADS)

Chalise, Sajju; Conlan, Skye; Porat, Zachary; Labrake, Scott; Vineyard, Michael

2017-09-01

The Union College Ion-Beam Analysis Lab's 1.1 MV tandem Pelletron accelerator is used to determine the presence of heavy trace metals in Queens, NY between Astoria Park and 3.5 miles south to Gantry State Park. A PIXE analysis was performed on 0.5 g pelletized soil samples with a 2.2 MeV proton beam. The results show the presence of elements ranging from Ti to Pb with the concentration of Pb in Astoria Park (2200 +/-200 ppm) approximately ten times that of the Gantry State Park. We hypothesize that the high lead concentration at Astoria Park is due to the nearby Hell Gate Bridge, painted in 1916 with lead based paint, then sandblasted and repainted in the '90s. If the lead is from the repair of the bridge, then we should see the concentration decrease as we go further from the bridge. To test this, soil samples were collected and analyzed from seven different locations north and south of the bridge. The concentrations of lead decreased drastically within a 500 m radius and were approximately constant at greater distances. More soil samples need to be collected within the 500 m radius from bridge to identify the potential source of Pb. We will describe the experimental procedure, the PIXE analysis of soil samples, and present preliminary results on the distribution of heavy trace metals.

PIXE and /μ-PIXE analysis of glazes from terracotta sculptures of the della Robbia workshop

NASA Astrophysics Data System (ADS)

Zucchiatti, Alessandro; Bouquillon, Anne; Giancarlo Lanterna; Lucarelli, Franco; Mandò, Pier Andrea; Prati, Paolo; Salomon, Joseph; Vaccari, Maria Grazia

2002-04-01

A series of PIXE analyses has been performed on glazes from terracotta sculptures of the Italian Renaissance and on reference standards. The problems related to the investigation of such heterogeneous materials are discussed and the experimental uncertainties are evaluated, for each element, from the PIXE analysis of standard glasses. Some examples from artefacts coming from Italian collections are given. This research has been conducted in the framework of the COST-G1 European action.

Combined PIXE and XPS analysis on republican and imperial Roman coins

NASA Astrophysics Data System (ADS)

Daccà, A.; Prati, P.; Zucchiatti, A.; Lucarelli, F.; Mandò, P. A.; Gemme, G.; Parodi, R.; Pera, R.

2000-03-01

A combined PIXE and XPS analysis has been performed on a few Roman coins of the republican and imperial age. The purpose was to investigate via XPS the nature and extent of patina in order to be capable of extracting PIXE data relative to the coins bulk. The inclusion of elements from the surface layer, altered by oxidation and inclusion, is a known source of uncertainty in PIXE analyses of coins, performed to assess the composition and the provenance.

Analysis of elements in lake sediment samples by PIXE spectrometry

NASA Astrophysics Data System (ADS)

Chelarescu, E. D.; Radulescu, C.; Stihi, C.; Bretcan, P.; Tanislav, D.; Dulama, I. D.; Stirbescu, R. M.; Teodorescu, S.; Bucurica, I. A.; Andrei, R.; Morarescu, C.

2017-09-01

This work aims to determine the concentrations of several elements (e.g. Pb, Ni, Zn, Mn, Cr, and Fe) from lake sediments, in order to characterize their origin and evolution. Particle Induced X-ray Emission (PIXE) technique using the 3 MV Tandetron™ particle accelerator from National Institute for R&D in Physics and Nuclear Engineering "Horia Hulubei" (IFIN-HH), Magurele-Bucharest, Romania, was applied. Sediment cores from different salt lakes from Romania (i.e. Amara Lake, Caineni Lake, and Movila Miresii Lake) were collected, in August 2015. The content of Pb, Cr, Mn, Fe, and Ni from sediment samples show similarities with other data presented in literature and international regulation. The Zn was the only element with a higher content in all samples (e.g. maximum 401.7-517.3 mg/kg d.w.).

Optimization experiments on a pixe system and its application to the analysis of trace elements in shaji

NASA Astrophysics Data System (ADS)

Yin, Zhongli; Zhang, Shunun; Jiang, Xinzhou; Ma, Changjun; Li, Zhenkun; Hao, Jifang; Zheng, Zhihao; Liu, Zhaoyuan; Liu, Zhengmin; Ma, Shuxun; Yang, Kunshan

1989-04-01

This paper describes briefly the optimization of a PIXE setup. Three proton energies 1.5, 2.0 and 2.5 MeV and four kinds of absorbers BE (132 μm), Be (460 μm), Al (28 μm) and Be plus Mylar (460 μm+600 μm) were used. The minimum detection limits (MDL) of PIXE for these various combinations were computed and compared. PIXE analysis of Shaji was performed as an application. The result shows that the stack absorber of 460 μm Be and 600 μm Mylar films and a 2.0 MeV proton energy are most suitable for PIXE analysis of Shaji. Results of the Shaji analysis are presented. Shaji is one of the common seabuckthoms. The Shaji referred to here belongs to Hippophae rhamnoides L. Subsp. Sinensis Rousi.

Uptake and cellular distribution, in four plant species, of fluorescently labeled mesoporous silica nanoparticles.

PubMed

Sun, Dequan; Hussain, Hashmath I; Yi, Zhifeng; Siegele, Rainer; Cresswell, Tom; Kong, Lingxue; Cahill, David M

2014-08-01

We report the uptake of MSNs into the roots and their movement to the aerial parts of four plant species and their quantification using fluorescence, TEM and proton-induced x - ray emission (micro - PIXE) elemental analysis. Monodispersed mesoporous silica nanoparticles (MSNs) of optimal size and configuration were synthesized for uptake by plant organs, tissues and cells. These monodispersed nanoparticles have a size of 20 nm with interconnected pores with an approximate diameter of 2.58 nm. There were no negative effects of MSNs on seed germination or when transported to different organs of the four plant species tested in this study. Most importantly, for the first time, a combination of confocal laser scanning microscopy, transmission electron microscopy and proton-induced X-ray emission (micro-PIXE) elemental analysis allowed the location and quantification MSNs in tissues and in cellular and sub-cellular locations. Our results show that MSNs penetrated into the roots via symplastic and apoplastic pathways and then via the conducting tissues of the xylem to the aerial parts of the plants including the stems and leaves. The translocation and widescale distribution of MSNs in plants will enable them to be used as a new delivery means for the transport of different sized biomolecules into plants.

Study of the spatial distribution of mercury in roots of vetiver grass (Chrysopogon zizanioides) by micro-pixe spectrometry.

PubMed

Lomonte, Cristina; Wang, Yaodong; Doronila, Augustine; Gregory, David; Baker, Alan J M; Siegele, Rainer; Kolev, Spas D

2014-01-01

Localization of Hg in root tissues of vetivergrass (Chrysopogon zizanioides) was investigated by micro-Proton Induced X-ray Emission (PIXE) spectrometry to gain a better understanding of Hg uptake and its translocation to the aerial plant parts. Tillers of C. zizanioides were grown in a hydroponic culture for 3 weeks under controlled conditions and then exposed to Hg for 10 days with or without the addition of the chelators (NH(4))(2)S(2)O(3) or KI. These treatments were used to study the effects of these chelators on localization of Hg in the root tissues to allow better understanding of Hg uptake during its assisted-phytoextraction. Qualitative elemental micro-PIXE analysis revealed that Hg was mainly localized in the root epidermis and exodermis, tissues containing suberin in all Hg treatments. Hg at trace levels was localized in the vascular bundle when plants were treated with a mercury solution only. However, higher Hg concentrations were found when the solution also contained (NH(4))(2)S(2)O(3) or KI. This finding is consistent with the observed increase in Hg translocation to the aerial parts of the plants in the case of chemically induced Hg phytoextraction.

Spatial investigation of some uranium minerals using nuclear microprobe

NASA Astrophysics Data System (ADS)

Valter, Anton A.; Knight, Kim B.; Eremenko, Gelij K.; Magilin, Dmitry V.; Ponomarov, Artem A.; Pisansky, Anatoly I.; Romanenko, Alexander V.; Ponomarev, Alexander G.

2018-01-01

In this work, several individual grains of uranium minerals—uraninite with high content of Ca, Ca-rich boltwoodite, growths of uranophane with β-uranophane, and weeksite—from different uranium deposits were studied by a scanning nuclear microprobe. Particle-induced X-ray emission technique provided by the microprobe (µ-PIXE) was carried out to obtain a concentration and 2D distribution of elements in these minerals. In addition, energy dispersive X-ray spectrometry (SEM-EDS) provided by a scanning electron microscope was used. The types of minerals were determined by X-ray diffraction methods. Results of this study improved the understanding of trace elemental composition of the uranium minerals depending on their origin. Obtained signatures could be linked then to the sample provenance. Such data are important for nuclear forensics to identify the ore types and even specific ore bodies, when only small samples may be available for analysis. In this study, the µ-PIXE technique was used for obtaining the 2D distribution of trace elements that are not commonly measured by SEM-EDS at the relevant concentrations. The detected levels and precisions of elements determination by µ-PIXE were also defined. Using µ-PIXE, several micro mineral inclusions such as phosphate with high level of V and Si were identified. The age of the uranium minerals was estimated due to a significant content of radiogenic Pb that provides an additional parameter for determination of the main attributive characteristics of the minerals. This work also showed that due to its high elemental sensitivity the nuclear microprobe can be a new analytical tool for creating a nuclear forensic database from the known uranium deposits and a subsequent analysis of the intercepted illicit materials.

Spatial investigation of some uranium minerals using nuclear microprobe

NASA Astrophysics Data System (ADS)

Valter, Anton A.; Knight, Kim B.; Eremenko, Gelij K.; Magilin, Dmitry V.; Ponomarov, Artem A.; Pisansky, Anatoly I.; Romanenko, Alexander V.; Ponomarev, Alexander G.

2018-06-01

In this work, several individual grains of uranium minerals—uraninite with high content of Ca, Ca-rich boltwoodite, growths of uranophane with β-uranophane, and weeksite—from different uranium deposits were studied by a scanning nuclear microprobe. Particle-induced X-ray emission technique provided by the microprobe (µ-PIXE) was carried out to obtain a concentration and 2D distribution of elements in these minerals. In addition, energy dispersive X-ray spectrometry (SEM-EDS) provided by a scanning electron microscope was used. The types of minerals were determined by X-ray diffraction methods. Results of this study improved the understanding of trace elemental composition of the uranium minerals depending on their origin. Obtained signatures could be linked then to the sample provenance. Such data are important for nuclear forensics to identify the ore types and even specific ore bodies, when only small samples may be available for analysis. In this study, the µ-PIXE technique was used for obtaining the 2D distribution of trace elements that are not commonly measured by SEM-EDS at the relevant concentrations. The detected levels and precisions of elements determination by µ-PIXE were also defined. Using µ-PIXE, several micro mineral inclusions such as phosphate with high level of V and Si were identified. The age of the uranium minerals was estimated due to a significant content of radiogenic Pb that provides an additional parameter for determination of the main attributive characteristics of the minerals. This work also showed that due to its high elemental sensitivity the nuclear microprobe can be a new analytical tool for creating a nuclear forensic database from the known uranium deposits and a subsequent analysis of the intercepted illicit materials.

Fast simulation of Proton Induced X-Ray Emission Tomography using CUDA

NASA Astrophysics Data System (ADS)

Beasley, D. G.; Marques, A. C.; Alves, L. C.; da Silva, R. C.

2013-07-01

A new 3D Proton Induced X-Ray Emission Tomography (PIXE-T) and Scanning Transmission Ion Microscopy Tomography (STIM-T) simulation software has been developed in Java and uses NVIDIA™ Common Unified Device Architecture (CUDA) to calculate the X-ray attenuation for large detector areas. A challenge with PIXE-T is to get sufficient counts while retaining a small beam spot size. Therefore a high geometric efficiency is required. However, as the detector solid angle increases the calculations required for accurate reconstruction of the data increase substantially. To overcome this limitation, the CUDA parallel computing platform was used which enables general purpose programming of NVIDIA graphics processing units (GPUs) to perform computations traditionally handled by the central processing unit (CPU). For simulation performance evaluation, the results of a CPU- and a CUDA-based simulation of a phantom are presented. Furthermore, a comparison with the simulation code in the PIXE-Tomography reconstruction software DISRA (A. Sakellariou, D.N. Jamieson, G.J.F. Legge, 2001) is also shown. Compared to a CPU implementation, the CUDA based simulation is approximately 30× faster.

Studying the spatial variability of Cr in agricultural field using both particle induced X-ray emission (PIXE) and instrumental neutron activation analysis (INAA) technique

NASA Astrophysics Data System (ADS)

Cruvinel, Paulo E.; Crestana, Sílvio; Artaxo, Paulo; Martins, JoséV.; Armelin, Maria JoséA.

1996-04-01

In the field of soil physics, a technique which permits a non-destructive, accurate and fast elemental analysis with a minimum of sample preparation effort is often desired. Although trace elements are minor components of the solid phase, they play an important role in soil fertility. Cr is of nutritional importance because it is a required element in human and animal nutrition. The immobility of Cr may be responsible for an inadequate Cr supply to plants. This work not only demonstrates the suitability of PIXE as a fast and non-destructive technique, useful to measure Cr content in soil samples, but also outlines a study of spatial variability of that element in agricultural field. To demonstrate the capability of the method soil samples were collected in a 5000 m 2 agricultural field. The soil samples were analyzed using both PIXE and INAA techniques. Besides, a Fourier interpolation technique was used to verify the distribution of Cr along of the sampled field. INAA was carried out by means of the γ-ray emitted by 51Cr(320 keV). Results show that there is a good linear relationship between the elemental concentration of Cr obtained using those techniques, i.e. a correlation coefficient of r2 = 0.82 was achieved.

PIXE analysis of medieval silver coins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelouahed, H. Ben, E-mail: habdelou@cern.ch; Gharbi, F.; Roumie, M.

2010-01-15

We applied the proton-induced X-ray emission (PIXE) analytical technique to twenty-eight medieval silver coins, selected from the Tunisian treasury. The purpose is to study the fineness evolution from the beginning of the 7th to the 15th centuries AD. Each silver coin was cleaned with a diluted acid solution and then exposed to a 3 MeV proton beam from a 1.7 MV tandem accelerator. To allow the simultaneous detection of light and heavy elements, a funny aluminum filter was positioned in front of the Si(Li) detector entrance which is placed at 135{sup o} to the beam direction. The elements Cu, Pb,more » and Au were observed in the studied coins along with the major component silver. The concentration of Ag, presumably the main constituent of the coins, varies from 55% to 99%. This significant variation in the concentration of the major constituent reveals the economical difficulties encountered by each dynasty. It could be also attributed to differences in the composition of the silver mines used to strike the coins in different locations. That fineness evolution also reflects the poor quality of the control practices during this medieval period. In order to verify the ability of PIXE analytical method to distinguish between apparently similar coins, we applied hierarchical cluster analysis to our results to classify them into different subgroups of similar elemental composition.« less

Electrochemical vs X-ray Spectroscopic Measurements of NiFe(CN)6 Crystals

NASA Astrophysics Data System (ADS)

Peecher, Benjamin; Hampton, Jennifer

Pseudocapacitive materials like hexacyanoferrate have greater energy storage capabilities than standard capacitors while maintaining an ability to charge and discharge quickly. We modify the surface of an electrodeposited Ni thin film with a layer of hexacyanoferrate. Charging and discharging these modified films using cyclic voltammetry (CV) allows us to measure the electrochemically active Fe in the film. To determine how closely this resembles the full amount of Fe in the film, we measure the films' composition using particle-induced x-ray emission (PIXE). We also vary the amount of Ni deposited, both to compare the electrolysis value of charge deposited to the PIXE measurement of Ni in the film, and also to measure how varying the thickness of the Ni surface affects the presence of Fe in the film. Comparisons of the CV and PIXE measurements show agreement in Ni levels but disagreement in Fe levels. PIXE measurements of Fe in the film have positive correlation with Ni in the film. This correlation between PIXE measurements of Ni and Fe suggests that PIXE provides a reliable measure of Fe in the film. This implies that a variable proportion of total Fe in a given film is electrochemically active. This research was made possible by the Hope College Department of Physics Frissel Research Fund and the National Science Foundation under Grants RUI-DMR-1104725, MRI-CHE-0959282, and MRI/RUI-PHY-0319523.

Ascertaining serum levels of trace elements in melanoma patients using PIXE and HR-ICPMS

NASA Astrophysics Data System (ADS)

Bernardes, S.; Tabacniks, M. H.; Santos, I. D. A. O.; Oliveira, A. F.; Shie, J. N.; Sarkis, J. E. S.; Oliveira, T.

2014-01-01

Melanoma is a serious and deadly form of skin cancer. However, patients' chances of survival and recovery are considerably increased when it is diagnosed and treated in its early stages. In this study, trace element concentrations in serum samples from patients with melanoma were measured using PIXE (Proton Induced X-ray Emission) and HR-ICPMS (High-Resolution Inductively Coupled Plasma Mass Spectrometry), with the purpose of correlating these concentrations with the disease. Blood samples from 30 melanoma patients and 116 healthy donors were collected at São Paulo Hospital (protocol CEP 1036/08 UNIFESP). Relevant clinical information on the patients has also been included in the statistical analysis. Analysis of the control group showed different P and Mg concentrations in individuals above and below 40 years of age. P, S, Ca, Cu and Zn concentrations in healthy individuals differed according to gender, highlighting the necessity to include age and gender variables in the case-control analysis. There were also differences in K, S, Ca and Se concentrations between the control and melanoma groups.

Detection of trace metallic elements in oral lichenoid contact lesions using SR-XRF, PIXE, and XAFS

PubMed Central

Sugiyama, Tomoko; Uo, Motohiro; Wada, Takahiro; Omagari, Daisuke; Komiyama, Kazuo; Miyazaki, Serika; Numako, Chiya; Noguchi, Tadahide; Jinbu, Yoshinori; Kusama, Mikio; Mori, Yoshiyuki

2015-01-01

Oral lichen planus (OLP) and oral lichenoid contact lesions (OLCL) are chronic inflammatory mucocutaneous reactions with a risk of malignant transformation that alter the epithelium. OLP and OLCL have similar clinical and histopathological features and it is difficult to distinguish one from the other. Metallic restorations are suspected to generate OLCLs. Trace metal analysis of OLCL specimens may facilitate the discrimination of symptoms and identification of causative metallic restorations. The purpose of this study was to assess OLCL tissue samples for the prevalence of metallic elements derived from dental restorations, and to discriminate OLCL from OLP by using synchrotron radiation-excited X-ray fluorescence analysis (SR-XRF), particle-induced X-ray emission (PIXE), and X-ray absorption fine structure (XAFS). Typical elements of dental materials were detected in the OLCL, whereas no obvious element accumulation was detected in OLP and negative control specimens. The origin of the detected metallic elements was presumed to be dental alloys through erosion. Therefore, our findings support the feasibility of providing supporting information to distinguish OLCL from OLP by using elemental analysis. PMID:26085368

PROTON MICROPROBE ANALYSIS OF TRACE-ELEMENT VARIATIONS IN VITRINITES IN THE SAME AND DIFFERENT COAL BEDS.

USGS Publications Warehouse

Minkin, J.A.; Chao, E.C.T.; Blank, Herma; Dulong, F.T.

1987-01-01

The PIXE (proton-induced X-ray emission) microprobe can be used for nondestructive, in-situ analyses of areas as small as those analyzed by the electron microprobe, and has a sensitivity of detection as much as two orders of magnitude better than the electron microprobe. Preliminary studies demonstrated that PIXE provides a capability for quantitative determination of elemental concentrations in individual coal maceral grains with a detection limit of 1-10 ppm for most elements analyzed. Encouraged by the earlier results, we carried out the analyses reported below to examine trace element variations laterally (over a km range) as well as vertically (cm to m) in the I and J coal beds in the Upper Cretaceous Ferron Sandstone Member of the Mancos Shale in central Utah, and to compare the data with the data from two samples of eastern coals of Pennsylvanian age.

PIXE analysis of tumors and localization behavior of a lanthanide in nude mice

NASA Astrophysics Data System (ADS)

Chang, Pei-Jiun; Yang, Czau-Siung; Chou, Ming-Ji; Wei, Chau-Chin; Hsu, Chu-Chung; Wang, Chia-Yu

1984-04-01

We have used particle induced X-ray emission (PIXE) to analyze the elemental compositions and uptakes of a lanthanide, yttrium in this report, in tumors and normal tissues of nude mice. A small amount of yttrium nitrate was injected into nude mice with tumors. Samples of normal and malignant tissues taken from these mice were bombarded by the 2 MeV proton beam from a 3 MeV Van de Graaff accelerator with a Ge detector system to determine the relative elemental compositions of tissues and the relative concentrations of yttrium taken up by these tissues. We found that the uptakes of yttrium by tumors were at least five times more than those by normal tissues. Substantial differences were often observed between the trace element weight (or concentration) pattern of the cancerous and normal tissues. The present result is compared with human tissues.

PIXE and ICP-MS Analysis of Andrographis Paniculata Medicinal Plant

NASA Astrophysics Data System (ADS)

Chandrasekhar Rao, J.; Naidu, B. G.; Sarita, P.; Srikanth, S.; Naga Raju, G. J.

2017-08-01

The concentrations of elements Li, Be, Al, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Ag, Cd, Ba, Pb and U in Andrographis Paniculata medicinal plant used in the treatment of Diabetes Mellitus were determined by using Particle Induced X-ray Emission (PIXE) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) techniques. This plant was collected from four different geographical locations in Andhra Pradesh, India in order to assess the regional variation of elemental concentrations. Appreciable levels of K, Ca, Cr, Mn, Cu and Zn determined in this plant can be correlated to the antidiabetic property of Andrographis Paniculata since these elements are known to regulate and potentiate insulin action. Presence of toxic elements As, Cd and Pb necessitates the adoption of precautionary measures while prescribing dosage of the herbal medicine prepared from this plant for the treatment diabetes mellitus.

Analysis of the fly ash from the processing of wood chips in a pilot-scale downdraft gasifier: Comparison of inorganic constituents determined by PIXE and ICP-AES

Treesearch

Thomas L Eberhardt; Hui Pan

2013-01-01

Gasification of biomass ultimately generates at least one solid byproduct in which the inorganic constituents of the biomass are concentrated. Given the potential for utilization, or issues with disposal, facile methods are needed for determining the compositions of the fly ashes from recently-available gasifier-based bioenergy systems. Proton induced x-ray emission...

Micro-PIXE and micro-RBS characterization of micropores in porous silicon prepared using microwave-assisted hydrofluoric acid etching.

PubMed

Ahmad, Muthanna; Grime, Geoffrey W

2013-04-01

Porous silicon (PS) has been prepared using a microwave-assisted hydrofluoric acid (HF) etching method from a silicon wafer pre-implanted with 5 MeV Cu ions. The use of microbeam proton-induced X-ray emission (micro-PIXE) and microbeam Rutherford backscattering techniques reveals for the first time the capability of these techniques for studying the formation of micropores. The porous structures observed from micro-PIXE imaging results are compared to scanning electron microscope images. It was observed that the implanted copper accumulates in the same location as the pores and that at high implanted dose the pores form large-scale patterns of lines and concentric circles. This is the first work demonstrating the use of microwave-assisted HF etching in the formation of PS.

Characterisation of traffic-generated particulate matter in Copenhagen

NASA Astrophysics Data System (ADS)

Wåhlin, Peter; Berkowicz, Ruwim; Palmgren, Finn

Fine and coarse fraction PM was simultaneously sampled with Dichotomous Stacked Filter Units at a road site and at an urban background site during both summer and winter periods. The collected mass was determined gravimetrically, and the contents of 26 elements were measured by Proton-Induced X-ray Emission (PIXE). NO x was monitored continuously at both sites. The road increments (road concentrations minus urban background concentrations) of PIXE elements, PM and NO x were analysed using the Constrained Physical Receptor Model (COPREM). Good agreement between the measured data and the model was achieved in both size fractions using four well-separated source profiles representing the emissions from exhaust, road/tyres, brakes and road salt. The analysis showed that the particles created by brake abrasion have aerodynamic diameters in the inhalable size range around 2.8 μm. This particle diameter is common mass median for a long list of heavy metals that are apportioned to the brakes source: Cr, Fe, Cu, Zn, Zr, Mo, Sn, Sb, Ba and Pb. Other significant contributions of Al, Si, K, Ca, Ti, Mn, Fe, Zn and Sr, mostly in the coarse particle fraction, are apportioned to the road/tyres source.

Ion beam analysis and PD-MS as new analytical tools for quality control of pharmaceuticals: comparative study from fluphenazine in solid dosage forms.

PubMed

Nsouli, Bilal; Bejjani, Alice; Negra, Serge Della; Gardon, Alain; Thomas, Jean-Paul

2010-09-01

In order to evaluate the potential of accelerator based analytical techniques ((particle induced X-ray emission (PIXE), particle induced gamma-ray emission (PIGE), and particle desorption mass spectrometry (PD-MS)) for the analysis of commercial pharmaceutical products in their solid dosage form, the fluphenazine drug has been taken as a representative example. It is demonstrated that PIXE and PIGE are by far the best choice for quantification of the active ingredient (AI) (certification with 7% precision) from the reactions induced on its specific heteroatoms fluorine and sulfur using pellets made from original tablets. Since heteroatoms cannot be present in all types of drugs, the PD-MS technique, which makes easily the distinction between AI(s) and excipients, has been evaluated for the same material. It is shown that the quantification of AI is obtained via the detection of its protonated molecule. However, calibration curves have to be made from the secondary ion yield variations since matrix effects of various nature are characteristics of such mixtures of heterogeneous materials (including deposits from soluble components). From the analysis of solid tablets, (either transformed into pellets and even as received), it is strongly suggested that the physical state of the grains in the mixture is a crucial parameter in the ion emission and accordingly for the calibration curves. As a result of our specific (but not optimized) conditions the resulting precision is <17% with an almost linear range extending from 0.04 to 7.87 mg of AI in a tablet made under the manufacturer conditions (the commercial drug product is labeled at 5 mg).

Single cell elemental analysis using nuclear microscopy

NASA Astrophysics Data System (ADS)

Ren, M. Q.; Thong, P. S. P.; Kara, U.; Watt, F.

1999-04-01

The use of Particle Induced X-ray Emission (PIXE), Rutherford Backscattering Spectrometry (RBS) and Scanning Transmission Ion Microscopy (STIM) to provide quantitative elemental analysis of single cells is an area which has high potential, particularly when the trace elements such as Ca, Fe, Zn and Cu can be monitored. We describe the methodology of sample preparation for two cell types, the procedures of cell imaging using STIM, and the quantitative elemental analysis of single cells using RBS and PIXE. Recent work on single cells at the Nuclear Microscopy Research Centre,National University of Singapore has centred around two research areas: (a) Apoptosis (programmed cell death), which has been recently implicated in a wide range of pathological conditions such as cancer, Parkinson's disease etc, and (b) Malaria (infection of red blood cells by the malaria parasite). Firstly we present results on the elemental analysis of human Chang liver cells (ATTCC CCL 13) where vanadium ions were used to trigger apoptosis, and demonstrate that nuclear microscopy has the capability of monitoring vanadium loading within individual cells. Secondly we present the results of elemental changes taking place in individual mouse red blood cells which have been infected with the malaria parasite and treated with the anti-malaria drug Qinghaosu (QHS).

Particle Induced X-Ray Emission experiment using the K150 3.6 MeV proton beam at TAMU Cyclotron Institute

NASA Astrophysics Data System (ADS)

Pajouhafsar, Yasmin; Alis Manso Rodriguez Team; Sherry Yennello Team

2017-09-01

Particle Induced X-Ray Emission (PIXE) is a non-destructive analytical technique that is used for various tasks, such as elemental composition. The x-rays are emitted when electrons transition from higher to lower energy levels, causing vacancies in the atom's electron configuration. The overall goals of this research are to successfully set up a PIXE experiment and to obtain elemental concentrations for various samples, using the K150 proton beam in the Cyclotron Institute at Texas A&M University. The x-rays produced are unique to each element and analyzed with reference to their known energies. The setup consists of 3 different detectors, providing a wide range of energies: XR-100T CdTe γ/X-Ray, XR-100T/CR Si and XR-100SDD. Accelerating 3.6 MeV protons from the K150 and using PIXE, we determine concentrations from the NaCl samples provided by the Chemical Engineering Department. The concentrations for each element found in the NaCl thin films are obtained and analyzed through the software, GUPIXWIN. DOE Grant (DE-FG02-93ER40773) and Welch Foundation (A-1266).

Multielemental analyses of isomorphous Indian garnet gemstones by XRD and external pixe techniques.

PubMed

Venkateswarulu, P; Srinivasa Rao, K; Kasipathi, C; Ramakrishna, Y

2012-12-01

Garnet gemstones were collected from parts of Eastern Ghats geological formations of Andhra Pradesh, India and their gemological studies were carried out. Their study of chemistry is not possible as they represent mixtures of isomorphism nature, and none of the individual specimens indicate independent chemistry. Hence, non-destructive instrumental methodology of external PIXE technique was employed to understand their chemistry and identity. A 3 MeV proton beam was employed to excite the samples. In the present study geochemical characteristics of garnet gemstones were studied by proton induced X-ray emission. Almandine variety of garnet is found to be abundant in the present study by means of their chemical contents. The crystal structure and the lattice parameters were estimated using X-Ray Diffraction studies. The trace and minor elements are estimated using PIXE technique and major compositional elements are confirmed by XRD studies. The technique is found very useful in characterizing the garnet gemstones. The present work, thus establishes usefulness and versatility of the PIXE technique with external beam for research in Geo-scientific methodology. Copyright © 2012 Elsevier Ltd. All rights reserved.

A dual-PIXE tomography setup for reconstruction of Germanium in ICF target

NASA Astrophysics Data System (ADS)

Guo, N.; Lu, H. Y.; Wang, Q.; Meng, J.; Gao, D. Z.; Zhang, Y. J.; Liang, X. X.; Zhang, W.; Li, J.; Ma, X. J.; Shen, H.

2017-08-01

Inertial Confinement Fusion (ICF) is one type of fusion energy research which could initiate nuclear fusion reactions through heating and compressing thermonuclear fuel. Compared to a pure plastic target, Germanium doping into the CH ablator layer by Glow Discharge Polymer (GDP) technique can increase the ablation velocity and the standoff distance between the ablation front and laser-deposition region. During target fabrication process, quantitative doping of Ge should be accurately controlled. Particle Induced X-ray Emission Tomography (PIXE-T) can make not only quantification of the concentration, but also reconstruction of the spatial distribution of doped element. The Si (Li) detector for PIXE tomography technique had a disadvantage of low counting rate. To make up this deficiency, another detector of Si (Li) with the same configuration positioned at the opposite side with the same detective angle 135° have been implemented. Simultaneously acquired elemental maps of Ge obtained using two detectors may be different because of the X-ray absorption along the X-ray exit route in the target. In this paper, the X-ray detection efficiency is drastically improved by this dual-PIXE tomography system.

PIXE analysis of caries related trace elements in tooth enamel

NASA Astrophysics Data System (ADS)

Annegarn, H. J.; Jodaikin, A.; Cleaton-Jones, P. E.; Sellschop, J. P. F.; Madiba, C. C. P.; Bibby, D.

1981-03-01

PIXE analysis has been applied to a set of twenty human teeth to determine trace element concentration in enamel from areas susceptible to dental caries (mesial and distal contact points) and in areas less susceptible to the disease (buccal surfaces), with the aim of determining the possible roles of trace elements in the curious process. The samples were caries-free anterior incisors extracted for periodontal reasons from subjects 10-30 years of age. Prior to extraction of the sample teeth, a detailed dental history and examination was carried out in each individual. PIXE analysis, using a 3 MeV proton beam of 1 mm diameter, allowed the determination of Ca, Mn, Fe, Cu, Zn, Sr and Pb above detection limits. As demonstrated in this work, the enhanced sensitivity of PIXE analysis over electron microprobe analysis, and the capability of localised surface analysis compared with the pooled samples required for neutron activation analysis, makes it a powerful and useful technique in dental analysis.

Preliminary application of tapered glass capillary microbeam in MeV-PIXE mapping of longan leaf for elemental concentration distribution analysis

NASA Astrophysics Data System (ADS)

Natyanun, S.; Unai, S.; Yu, L. D.; Tippawan, U.; Pussadee, N.

2017-09-01

This study was aimed at understanding elemental concentration distribution in local longan leaf for how the plant was affected by the environment or agricultural operation. The analysis applied the MeV-microbeam particle induced X-ray emission (PIXE) mapping technique using a home-developed tapered glass capillary microbeam system at Chiang Mai University. The microbeam was 2-MeV proton beam in 130 µm in diameter. The studying interest was in the difference in the elemental concentrations distributed between the leaf midrib and lamina areas. The micro proton beam analyzed the leaf sample across the leaf midrib edge to the leaf lamina area for total 9 data requisition spots. The resulting data were colored to form a 1D-map of the elemental concentration distribution. Seven dominant elements, Al, S, Cl, K, Ca, Sc and Fe, were identified, the first six of which were found having higher concentrations in the midrib area than in the lamina area, while the Fe concentration was in an opposite trend to that of the others.

PIXE Analysis of Artificial Turf

NASA Astrophysics Data System (ADS)

Conlan, Skye; Chalise, Sajju; Porat, Zachary; Labrake, Scott; Vineyard, Michael

2017-09-01

In recent years, there has been debate regarding the use of the crumb rubber infill in artificial turf on high school and college campuses due to the potential presence of heavy metals and carcinogenic chemicals. We performed Proton-Induced X-Ray Emission (PIXE) analysis of artificial turf infill and blade samples collected from high school and college campuses around the Capital District of NYS to search for potentially toxic substances. Crumb rubber pellets were made by mixing 1g of rubber infill and 1g of epoxy. The pellets and the turf blades were bombarded with 2.2 MeV proton beams from a 1.1-MV tandem Pelletron accelerator in the Union College Ion-Beam Analysis Laboratory and x-ray energy spectra were collected with an Amptek silicon drift detector. We analyzed the spectra using GUPIX software to determine the elemental concentrations of the samples. The turf infill showed significant levels of Ti, Fe, Co, Ni, Cu, Zn, Br, and Pb. The highest concentration of Br in the crumb rubber was 1500 +/-100 ppm while the highest detectable amount of Pb concentration was 110 +/-20 ppm. The artificial turf blades showed significant levels of Ti, Fe, and Zn with only the yellow blade showing concentrations of V and Bi.

Bio-metals imaging and speciation in cells using proton and synchrotron radiation X-ray microspectroscopy

PubMed Central

Ortega, Richard; Devès, Guillaume; Carmona, Asunción

2009-01-01

The direct detection of biologically relevant metals in single cells and of their speciation is a challenging task that requires sophisticated analytical developments. The aim of this article is to present the recent achievements in the field of cellular chemical element imaging, and direct speciation analysis, using proton and synchrotron radiation X-ray micro- and nano-analysis. The recent improvements in focusing optics for MeV-accelerated particles and keV X-rays allow application to chemical element analysis in subcellular compartments. The imaging and quantification of trace elements in single cells can be obtained using particle-induced X-ray emission (PIXE). The combination of PIXE with backscattering spectrometry and scanning transmission ion microscopy provides a high accuracy in elemental quantification of cellular organelles. On the other hand, synchrotron radiation X-ray fluorescence provides chemical element imaging with less than 100 nm spatial resolution. Moreover, synchrotron radiation offers the unique capability of spatially resolved chemical speciation using micro-X-ray absorption spectroscopy. The potential of these methods in biomedical investigations will be illustrated with examples of application in the fields of cellular toxicology, and pharmacology, bio-metals and metal-based nano-particles. PMID:19605403

On the Applications of IBA Techniques to Biological Samples Analysis: PIXE and RBS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Falcon-Gonzalez, J. M.; Bernal-Alvarado, J.; Sosa, M.

2008-08-11

The analytical techniques based on ion beams or IBA techniques give quantitative information on elemental concentration in samples of a wide variety of nature. In this work, we focus on PIXE technique, analyzing thick target biological specimens (TTPIXE), using 3 MeV protons produced by an electrostatic accelerator. A nuclear microprobe was used performing PIXE and RBS simultaneously, in order to solve the uncertainties produced in the absolute PIXE quantifying. The advantages of using both techniques and a nuclear microprobe are discussed. Quantitative results are shown to illustrate the multielemental resolution of the PIXE technique; for this, a blood standard wasmore » used.« less

Micro-PIXE study of Ag in digestive glands of a nano-Ag fed arthropod ( Porcellio scaber, Isopoda, Crustacea)

NASA Astrophysics Data System (ADS)

Tkalec, Živa Pipan; Drobne, Damjana; Vogel-Mikuš, Katarina; Pongrac, Paula; Regvar, Marjana; Štrus, Jasna; Pelicon, Primož; Vavpetič, Primož; Grlj, Nataša; Remškar, Maja

2011-10-01

Micro-proton induced X-ray emission (micro-PIXE) method was applied to study the micro-localization of silver (Ag) in digestive glands of a terrestrial arthropod (Porcellio scaber) after feeding on silver nanoparticles (nano-Ag) dosed food. The aim of our work was to assess whether feeding on nano-Ag results in the assimilation of silver (Ag) in digestive gland cells. To study micro-localization and elemental distribution of Ag, the animals were fed on food dosed with nanoparticles for 14 days under controlled laboratory conditions. At the end of the feeding exposure, the animals were dissected and digestive glands prepared for micro-PIXE analyses and TEM investigation. The results obtained by micro-PIXE documented high amounts of Ag inside S-cells of the digestive gland epithelium; however, TEM investigation did not show particle aggregates inside digestive gland cells. Also no adverse effect on feeding behavior was recorded what is a measure of toxic effects. We explain the presence of Ag inside the cells as a result of the assimilation of dissoluted Ag ions from ingested nano-Ag particles. Assimilation of excessive amounts of ingested metal ions in S-cells is a well known metal detoxification mechanism in isopods. We discuss the advantages of using micro-PIXE for the micro-localization of elements in biological tissue in studies of interactions between nanoparticles and biological systems.

PIXE study on the provenance of Chinese ancient porcelain

NASA Astrophysics Data System (ADS)

Zhu, D.; Cheng, H. S.; Lin, J. W.; Yang, F. J.

2006-08-01

This paper reports the PIXE study on the provenance of Chinese ancient porcelain made in 7-10th century. The chemical compositions of Jun celadon samples made at Juntai, Linru and Hunyuan kilns, the white-glazed porcelain samples made at Ding, Huangye and Dangyangyu kilns, and the Ru celadon samples made at Qiangliang Temple were measured by external-beam PIXE, and the factor analysis was applied for identifying their provenances. Experimental results show that the porcelain products made at different kilns can be distinguished according to the compositional differences measured by PIXE.

PIXE analysis of elements in gastric cancer and adjacent mucosa

NASA Astrophysics Data System (ADS)

Liu, Qixin; Zhong, Ming; Zhang, Xiaofeng; Yan, Lingnuo; Xu, Yongling; Ye, Simao

1990-04-01

The elemental regional distributions in 20 resected human stomach tissues were obtained using PIXE analysis. The samples were pathologically divided into four types: normal, adjacent mucosa A, adjacent mucosa B and cancer. The targets for PIXE analysis were prepared by wet digestion with a pressure bomb system. P, K, Fe, Cu, Zn and Se were measured and statistically analysed. We found significantly higher concentrations of P, K, Cu, Zn and a higher ratio of Cu compared to Zn in cancer tissue as compared with normal tissue, but statistically no significant difference between adjacent mucosa and cancer tissue was found.

Total elemental composition analysis of soil samples using the PIXE technique

NASA Astrophysics Data System (ADS)

Bolormaa, Oyuntsetseg; Baasansuren, Jamsranjav; Kawasaki, Katsunori; Watanabe, Makiko; Hattroi, Toshiyuki

2007-09-01

The determination of major and trace element contents in soils was developed by acid digestion method combined with particle-induced X-ray emission spectrometry (PIXE). The digestion of soils was achieved by using nitric acid (HNO3), hydrochloric acid HCl and hydrogen peroxide (H2O2) with repeated additions. A 20 μL aliquot from the digested samples was evaporated on the Nuclepore Track-Etch Membrane and irradiated by the 2.5 MeV proton beam from the single-end type Van de Graaff accelerator. The accuracy of this methodology was estimated based on series of measurements done for a reference material of soil CRM 023-050. The proposed experimental procedure was shown to have good reproducibility of the experimental results. The corresponding limits of detection (LODs) for Na, Mg, Al, P, S, Cl, K, Cr, Mn, Fe, Ni, Cu, Zn, As, Sr, Mo and Cd were estimated. Other soil characteristics such as total carbon (TC) and nitrogen (TN) content, pH and electrical conductivity (EC) were also measured.

Pix proteins and the evolution of centrioles.

PubMed

Woodland, Hugh R; Fry, Andrew M

2008-01-01

We have made a wide phylogenetic survey of Pix proteins, which are constituents of vertebrate centrioles in most eukaryotes. We have also surveyed the presence and structure of flagella or cilia and centrioles in these organisms, as far as is possible from published information. We find that Pix proteins are present in a vast range of eukaryotes, but not all. Where centrioles are absent so are Pix proteins. If one considers the maintenance of Pix proteins over evolutionary time scales, our analysis would suggest that their key function is to make cilia and flagella, and the same is true of centrioles. Moreover, this survey raises the possibility that Pix proteins are only maintained to make cilia and flagella that undulate, and even then only when they are constructed by transporting ciliary constituents up the cilium using the intraflagellar transport (IFT) system. We also find that Pix proteins have become generally divergent within Ecdysozoa and between this group and other taxa. This correlates with a simplification of centrioles within Ecdysozoa and a loss or divergence of cilia/flagella. Thus Pix proteins act as a weathervane to indicate changes in centriole function, whose core activity is to make cilia and flagella.

Analysis of elemental composition of porcelains unearthed from Waguantan kiln site by PIXE-RBS

NASA Astrophysics Data System (ADS)

Zhou, Z.; Zhang, K.; Xia, C. D.; Liu, M. T.; Zhu, J. J.; An, Z.; Bai, B.

2015-03-01

A method combining proton-induced X-ray emission spectrometry (PIXE) and Rutherford backscattering spectrometry (RBS) was used to determine the composition of 61 porcelain shards from the Yuan Dynasty (1271-1368 A.D.) unearthed from the Waguantan kiln site at Tianzhu County in Guizhou Province, China. Based on our previous experimental setup, an electron gun device with a LaB6 crystal cathode was installed to solve the problem created when the incident proton beams generated electric charge accumulations on the surfaces of the insulating porcelain samples, which induced a large bremsstrahlung background. The use of the electron gun has largely eliminated the large bremsstrahlung background and has therefore improved the detection limits for elements, especially for trace elements, and made it possible to determine the origin of the porcelains based on the trace elements. Major and trace elemental compositions of the porcelain bodies and glazes measured by PIXE and RBS were analyzed by the factor analysis method. The factor analysis showed that a few pieces of porcelain with a style similar to the porcelain of the Longquan kiln among the unearthed porcelains from the Waguantan kiln site did not have obvious differences in elemental compositions from other remaining porcelains unearthed from the Waguantan kiln site, indicating that the pieces of unearthed porcelain with the Longquan kiln style did in fact belong to the product fired locally by imitating the model of the Longquan celadon with local raw materials. This result therefore indicated that the Longquan kiln technology that originated from the Five Dynasties (907-960 A.D.) had been propagated to the Waguantan kiln site of Guizhou Province in the Yuan Dynasty.

Trace-element measurements in atmospheric biomonitors—A look at the relative performance of INAA and PIXE on olive-tree bark

NASA Astrophysics Data System (ADS)

Pacheco, Adriano M. G.; Freitas, Maria do Carmo; Reis, Miguel A.

2003-06-01

As part of an ongoing evaluation of its suitability for atmospheric biomonitoring, bark from olive trees ( Olea europaea Linn.) has been collected and searched for trace elements by means of two nuclear-analytical techniques—instrumental neutron activation analysis (INAA) and proton-induced X-ray emission (PIXE). The sampling for the present study was carried out across two separate sections of an established grid for air-quality surveys in mainland Portugal. The dual location comprises 58 collection sites—littoral-north (29 sites) and littoral-centre (29 sites). Both techniques are intrinsically accurate and may be seen to complement each other in the way that, as a whole, they yield 46 elements, with an overlap of 16 elements. Among the latter, this paper focuses on four of them and looks into their joint determination. Descriptive statistics for soil-related Al and Ti, and for sea-related Cl and Br, show results for each element to be fairly comparable. The degree of association between elemental patterns by either technique, as seen through nonparametric tests (Kendall's RK), is outstanding. No statistical evidence (Wilcoxon's T) for relative bias in correlated samples—consistently higher or lower results by one technique—could be found as well. As far as this study goes, INAA and PIXE may be used interchangeably for determining the present elements in olive-tree bark.

Ion Beam Facility at the University of Chile; Applications and Basic Research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miranda, P. A.; Morales, J. R.; Cancino, S.

2010-08-04

The main characteristics of the ion beam facility based on a 3.75 MeV Van de Graaff accelerator at the University of Chile are described at this work. Current activities are mainly focused on the application of the Ion Beam Analysis techniques for environmental, archaeological, and material science analysis. For instance, Rutherford Backscattering Spectrometry (RBS) is applied to measure thin gold film thickness which are used to determine their resistivity and other electrical properties. At this laboratory the Proton Induced X-Ray Emission (PIXE) and Proton Elastic Scattering Analysis (PESA) methodologies are extensively used for trace element analysis of urban aerosols (Santiago,more » Ciudad de Mexico). A similar study is being carried out at the Antarctica Peninsula. Characterization studies on obsidian and vitreous dacite samples using PIXE has been also perform allowing to match some of these artifacts with geological source sites in Chile.Basic physics research is being carried out by measuring low-energy cross section values for the reactions {sup 63}Cu(d,p){sup 64}Cu and {sup Nat}Zn(p,x){sup 67}Ga. Both radionuclide {sup 64}Cu and {sup 67}Ga are required for applications in medicine. Ongoing stopping power cross section measurements of proton and alphas on Pd, Cu, Bi and Mylar are briefly discussed.« less

Ion Beam Facility at the University of Chile; Applications and Basic Research

NASA Astrophysics Data System (ADS)

Miranda, P. A.; Morales, J. R.; Cancino, S.; Dinator, M. I.; Donoso, N.; Sepúlveda, A.; Ortiz, P.; Rojas, S.

2010-08-01

The main characteristics of the ion beam facility based on a 3.75 MeV Van de Graaff accelerator at the University of Chile are described at this work. Current activities are mainly focused on the application of the Ion Beam Analysis techniques for environmental, archaeological, and material science analysis. For instance, Rutherford Backscattering Spectrometry (RBS) is applied to measure thin gold film thickness which are used to determine their resistivity and other electrical properties. At this laboratory the Proton Induced X-Ray Emission (PIXE) and Proton Elastic Scattering Analysis (PESA) methodologies are extensively used for trace element analysis of urban aerosols (Santiago, Ciudad de Mexico). A similar study is being carried out at the Antarctica Peninsula. Characterization studies on obsidian and vitreous dacite samples using PIXE has been also perform allowing to match some of these artifacts with geological source sites in Chile. Basic physics research is being carried out by measuring low-energy cross section values for the reactions 63Cu(d,p)64Cu and NatZn(p,x)67Ga. Both radionuclide 64Cu and 67Ga are required for applications in medicine. Ongoing stopping power cross section measurements of proton and alphas on Pd, Cu, Bi and Mylar are briefly discussed.

Time resolved aerosol monitoring in the urban centre of Soweto

NASA Astrophysics Data System (ADS)

Formenti, P.; Annegarn, H. J.; Piketh, S. J.

1998-03-01

A programme of aerosol sampling was conducted from 1982 to 1984 in the urban area of Soweto, Johannesburg, South Africa. The particulate matter (aerodynamic diameter <15 μm) was collected using a two hours time resolution single stage streaker sampler and elemental concentrations were resolved via Particle Induced X-ray Emission (PIXE) analysis. Samples have been selected for analysis from an aerosol sample archive to establish base-line atmospheric conditions that existed in Soweto prior to large scale electrification, and to establish source apportionment of crustal elements between coal smoke and traffic induced road dust, based on chemical elemental measurements. A novel technique is demonstrated for processing PIXE-derived time sequence elemental concentration vectors. Slowly varying background components have been extracted from sulphur and crustal aerosol components, using alternatively two digital filters: a moving minimum, and a moving average. The residuals of the crustal elements, assigned to locally generated aerosol components, were modelled using surrogate tracers: sulphur as a surrogate for coal smoke; and Pb as a surrogate for traffic activity. Results from this source apportionment revealed coal emissions contributed between 40% and 50% of the aerosol mineral matter, while 18-22% originated from road dust. Background aerosol, characteristic of the regional winter aerosol burden over the South African Highveld, was between 12% and 21%. Minor contributors identified included a manganese smelter, located 30 km from the sampling site, and informal trash burning, as the source of intermittent heavy metals (Cu, Zn). Elemental source profiles derived for these various sources are presented.

PIXE as a complement to ICP-OES trace metal analysis in Sudanese medicinal plants.

PubMed

Mubark Ebrahim, Ammar; Etayeb, M A; Khalid, H; Noun, Manale; Roumie, M; Michalke, B

2014-08-01

This paper compares trace element concentrations (Ca, K, Sr, Fe, Mn, Zn, Ni, Cu, Co and Cr) in 27 Sudanese medical plants determined in parallel by PIXE and ICP-OES to get information on which technique is preferable at different matrices and element concentrations. PIXE correlates well to ICP-OES for Sr, Mn, Ca, K, Zn and Fe determinations. ICP-OES seems to be the superior technique over PIXE when measuring low concentrated elements (chromium, cobalt, nickel and copper) in the medicinal plants. Copyright © 2014 Elsevier Ltd. All rights reserved.

Large scale intercomparison of aerosol trace element analysis by different analytical methods

NASA Astrophysics Data System (ADS)

Bombelka, E.; Richter, F.-W.; Ries, H.; Wätjen, U.

1984-04-01

The general agreement of PIXE analysis with other methods (INAA, XRF, AAS, OES-ICP, and PhAA) is very good based on the analysis of filter pieces taken from 250 aerosol samples. It is better than 5% for Pb and Zn, better than 10% for V, Cr, and Mn, indicating that the accuracy of PIXE analysis can be within 10%. For elements such as Cd and Sb, difficult to analyze by PIXE because of their low mass content in the sample, the agreement is given mainly by the reproducibility of the method (20% to 30%). Similar agreement is found for sulfur, after taking account of the depth distribution of the aerosol in the filter.

PIXE analysis of cystic fibrosis sweat samples with an external proton beam

NASA Astrophysics Data System (ADS)

Sommer, F.; Massonnet, B.

1987-03-01

PIXE analysis with an external proton beam is used to study, in four control and five cystic fibrosis children, the elemental composition of sweat samples collected from different parts of the body during entire body hyperthermia. We observe no significant difference of sweat rates and of temperature variations between the two groups during sweat test. The statistical study of results obtained by PIXE analysis allows us to pick out amongst 8 elements studied, 6 elements (Na, Cl, Ca, Mn, Cu, Br) significatively different between the two groups of subjects. Using regression analysis, Na, Cl and Br concentrations could be used in a predictive equation of the state of health.

Enhanced identification of trace element fingerprint of prehistoric pigments by PIXE mapping

NASA Astrophysics Data System (ADS)

Lebon, M.; Pichon, L.; Beck, L.

2018-02-01

The elemental composition of Fe rich rocks used as pigment during prehistoric periods can provide valuable information about the type of material used and their geological origin. However, these materials present several analytical constraints since their patrimonial value involve using non-invasive techniques maintaining a high sensitivity of the detection and the quantification of trace elements. Micro-beam techniques also require to take into account the heterogeneity of these geomaterials from the macroscopic to microscopic scales. Several previous studies have demonstrated that PIXE analysis satisfies these analytical conditions. However, application of micro-PIXE analysis is still complex when thin and discontinuous layer of pigment is deposed on the surface of other materials such as rocks or bones. In such case, PIXE imaging could improve the ability to take into account the high heterogeneity of such archaeological objects. In study, we used PIXE imaging system developed at the NewAGLAE facility in order to visualize distribution of elements associated with iron-rich pigment phase. The results obtained show that PIXE maps can improve the identification of the main trace elements specific to the iron mineral phase. By grouping pixels of iron-rich areas and performing quantitative treatment, it was possible to reveal additional trace elements associated to pigment. This study highlights the contribution of PIXE imaging to the identification of elements associated with mineral phases of interest and to use them as proxies to discriminate different geological materials used in archaeological context.

PIXE analysis of historical paintings: Is the gain worth the risk?

NASA Astrophysics Data System (ADS)

Calligaro, T.; Gonzalez, V.; Pichon, L.

2015-11-01

The PIXE analysis of easel paintings constitutes a challenging task. Despite recognized merits and a few emblematic applications, PIXE has never been routinely applied to these fragile, complex and precious targets. The present work discusses the place of PIXE in the study of easel paintings and opens up perspectives for a more systematic usage of this analytical technique. Progress achieved since decades in the implementation of PIXE to study such fragile cultural heritage artefacts is reviewed, notably at the LABEC laboratory in Italy and at the AGLAE facility of the C2RMF in France. Two specific techniques developed for paintings are detailed and exemplified on Renaissance painting masterpieces: differential PIXE for paint layers depth profiling and multi-scale elemental mapping for the imaging of pigment distribution. Beam-induced damage, a major concern, notably depends on the employed beam fluence in particle/cm2 or μC/cm2. After recalling previous works on damage induced in chemical products comparable to pigments, we present the behaviour under different fluences of protons of a few MeV (1-300 μC/cm2) of targets having high resemblance to historical easel paintings: pellets of specially synthesized lead white pigments, layers of lead white mixed with linseed oil and areas containing lead white of two 19th century paintworks. The results shed new lights on the behaviour of paintworks under the beam and pave the way to strategies for damage mitigation. In particular, the lowering of PIXE performance induced by the decrease of the beam fluence sets a trade-off between risk of damage and gained information which also impacts the PIXE scanning protocol for paintings. As an illustration of an adequate adjustment of this balance, we report the exploratory application of PIXE mapping to a large area of a 19th century easel painting without damage. The recorded elemental maps are compared to elemental maps collected on the same area using laboratory-based scanning XRF.

Fixation and chemical analysis of single fog and rain droplets

NASA Astrophysics Data System (ADS)

Kasahara, M.; Akashi, S.; Ma, C.-J.; Tohno, S.

Last decade, the importance of global environmental problems has been recognized worldwide. Acid rain is one of the most important global environmental problems as well as the global warming. The grasp of physical and chemical properties of fog and rain droplets is essential to make clear the physical and chemical processes of acid rain and also their effects on forests, materials and ecosystems. We examined the physical and chemical properties of single fog and raindrops by applying fixation technique. The sampling method and treatment procedure to fix the liquid droplets as a solid particle were investigated. Small liquid particles like fog droplet could be easily fixed within few minutes by exposure to cyanoacrylate vapor. The large liquid particles like raindrops were also fixed successively, but some of them were not perfect. Freezing method was applied to fix the large raindrops. Frozen liquid particles existed stably by exposure to cyanoacrylate vapor after freezing. The particle size measurement and the elemental analysis of the fixed particle were performed in individual base using microscope, and SEX-EDX, particle-induced X-ray emission (PIXE) and micro-PIXE analyses, respectively. The concentration in raindrops was dependent upon the droplet size and the elapsed time from the beginning of rainfall.

Heavy metals concentrations in scalp hairs of ASGM miners and inhabitants of the Gorontalo Utara regency

NASA Astrophysics Data System (ADS)

Indriati Arifin, Yayu; Sakakibara, Masayuki; Sera, Koichiro

2017-06-01

We performed the Particle Induced X-ray Emission (PIXE) analysis on scalp hair samples of 115 ASGM miners and inhabitants of Gorontalo Utara regency. Along with mercury (Hg), we presented other trace elements such as Copper (Cu) and Manganese (Mn). Concentrations of Cu, Mn and Hg in the scalp hairs of ASGM miners are higher non miners. Significant and positive correlations coefficients between Cu and Hg concentration with Mn concentration may indicate that there are still unknown metabolism process related with ASGM activities.

Elemental and structural studies at the bone-cartilage interface

NASA Astrophysics Data System (ADS)

Bradley, D. A.; Kaabar, W.; Gundogdu, O.

2012-02-01

The techniques μProton-Induced X-and γ-ray Emission, μ-PIXE and μ-PIGE, were used to investigate trace and essential element distributions in sections of normal and osteoarthritic (OA) human femoral head. μ-PIGE yielded 2-D mappings of Na and F while Ca, Z, P and S were mapped by μ-PIXE. The concentration of chondroitin sulphate supporting functionality in healthy cartilage is significantly reduced in OA samples. Localised Zn points to osteoblastic/osteoclastic activity at the bone-cartilage interface. Small-angle X-ray scattering applied to decalcified OA-affected tissue showed spatial alterations of collagen fibres of decreased axial periodicity compared to normal collagen type I.

Non-destructive analysis and appraisal of ancient Chinese porcelain by PIXE

NASA Astrophysics Data System (ADS)

Cheng, H. S.; Zhang, Z. Q.; Xia, H. N.; Jiang, J. C.; Yang, F. J.

2002-05-01

This paper reports the results of the PIXE analysis on ancient Chinese blue and white porcelain fired at Kuan Kiln (Jingdezhen, Jiangxi province) during 13-19th century. The major, minor and trace element of porcelain body, white glaze and blue glaze were determined by PIXE. In this paper the chemical compositions of porcelain body, white glaze and blue glaze measured from Yuan (AD 1206-1368), Ming (AD 1368-1644) and Qing (AD 1616-1911) blue and white porcelain are present. The cobalt blue pigment used in Yuan, Ming and Qing are also discussed.

Bioaccumulation characterization of uranium by a novel Streptomyces sporoverrucosus dwc-3.

PubMed

Li, Xiaolong; Ding, Congcong; Liao, Jiali; Du, Liang; Sun, Qun; Yang, Jijun; Yang, Yuanyou; Zhang, Dong; Tang, Jun; Liu, Ning

2016-03-01

The biosorption mechanisms of uranium on an aerobic bacterial strain Streptomyces sporoverrucosus dwc-3, isolated from a potential disposal site for (ultra-)low uraniferous radioactive waste in Southwest China, were evaluated by using transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), proton induced X-ray emission (PIXE) and enhanced proton backscattering spectrometry (EPBS). Approximately 60% of total uranium at an initial concentration of 10mg/L uranium nitrate solution could be absorbed on 100mg S. sporoverrucosus dwc-3 with an adsorption capacity of more than 3.0mg/g (wet weight) after 12hr at room temperature at pH3.0. The dynamic biosorption process of S. sporoverrucosus dwc-3 for uranyl ions was well described by a pseudo second-order model. S. sporoverrucosus dwc-3 could accumulate uranium on cell walls and within the cell, as revealed by SEM and TEM analysis as well as EDX spectra. XPS and FT-IR analysis further suggested that the absorbed uranium was bound to amino, phosphate and carboxyl groups of the cells. Additionally, PIXE and EPBS results confirmed that ion exchange also contributed to the adsorption process of uranium. Copyright © 2015. Published by Elsevier B.V.

Characterization of inertial confinement fusion (ICF) targets using PIXE, RBS, and STIM analysis.

PubMed

Li, Yongqiang; Liu, Xue; Li, Xinyi; Liu, Yiyang; Zheng, Yi; Wang, Min; Shen, Hao

2013-08-01

Quality control of the inertial confinement fusion (ICF) target in the laser fusion program is vital to ensure that energy deposition from the lasers results in uniform compression and minimization of Rayleigh-Taylor instabilities. The technique of nuclear microscopy with ion beam analysis is a powerful method to provide characterization of ICF targets. Distribution of elements, depth profile, and density image of ICF targets can be identified by particle-induced X-ray emission, Rutherford backscattering spectrometry, and scanning transmission ion microscopy. We present examples of ICF target characterization by nuclear microscopy at Fudan University in order to demonstrate their potential impact in assessing target fabrication processes.

Elemental analysis with external-beam PIXE

NASA Astrophysics Data System (ADS)

Lin, E. K.; Wang, C. W.; Teng, P. K.; Huang, Y. M.; Chen, C. Y.

1992-05-01

A beamline system and experimental setup has been established for elemental analysis using PIXE with an external beam. Experiments for the study of the elemental composition of ancient Chinese potsherds (the Min and Ching ages) were performed. Continuum X-ray spectra from the samples bombarded by 3 MeV protons have been measured with a Si(Li) detector. From the analysis of PIXE data, the concentration of the main elements (Al, Si, K, and Ca) and of more than ten trace elements in the matrices and glazed surfaces were determined. Results for two different potsherds are presented, and those obtained from the glaze colorants are compared with the results of measurements on a Ching blue-and-white porcelain vase.

Elemental distribution patterns in the skins of false killer whales (Pseudorca crassidens) from a mass stranding in South Africa, analysed using micro-PIXE

NASA Astrophysics Data System (ADS)

Mouton, M.; Botha, A.; Thornton, M.; Mesjasz-Przybyłowicz, J.; Przybyłowicz, W. J.

2015-11-01

Several studies revealed that anthropogenic activities often cause toxic concentrations of some elements, such as mercury, which bio-accumulate through the marine food chain, impacting negatively on the health of animals in the top trophic levels, such as a variety of marine mammals. Moreover, analysis of cetacean skin has been reported to be a reliable, long-term and mostly non-invasive method to monitor bio-accumulation of chemicals in cetacean populations. Several elements, including trace elements, occur naturally in cetacean skin, although nothing is known about their distribution patterns and little about safe base line concentrations. In May 2009, 42 false killer whales (FKWs) beached and died at Kommetjie in the Western Cape of South Africa. Skin samples of these FKWs were collected and analysed to determine elemental distribution patterns. The concentrations and distribution patterns of the major, as well as detectable trace elements were determined in skin samples from ten randomly selected FKW individuals, using micro-PIXE (particle-induced X-ray emission) analysis. Results revealed differences between the distribution patterns of elements in the skin sections. Fe, for example, was found to be concentrated in the dermal papillae, whereas the highest Zn concentrations occurred in the epidermis and particularly in the epidermal papillae. Since these essential elements mediate factors such as host immunity, from skin integrity to humoral immunity, knowledge of their typical distribution patterns can be of great value in studies of bio-accumulation. This is the first report of micro-PIXE being employed to study elemental distribution in cetacean skin and the resulting elemental distribution maps can serve as reference in future environmental pollution studies.

Fluorine analysis of human dentin surrounding resin composite after fluoride application by μ-PIGE/PIXE analysis

NASA Astrophysics Data System (ADS)

Okuyama, Katsushi; Komatsu, Hisanori; Yamamoto, Hiroko; Pereira, Patricia N. R.; Bedran-Russo, Ana K.; Nomachi, Masaharu; Sato, Takahiro; Sano, Hidehiko

2011-10-01

The use of fluoride for the prevention of caries is based on the transformation of hydroxylapatite to fluoroapatite in the presence of fluoride ions, thereby strengthening tooth structure. Adhesion of dentin and resin composite (tooth-colored restoration material) requires a dentin bonding system, since resin composite is not able to adhere to dentin directly. Demineralization of dentin by acid etching is an important step in the dentin bonding system, however, demineralization also introduces weaknesses in tooth structure. If the demineralized dentin could be strengthened by the application of fluoride, then the dentin-resin composite bond strength might also improve. To test this hypothesis, the present study evaluated the influence of fluoride applications on the strength of the dentin-resin composite bond by (1) tensile strength testing analyses, (2) SEM analyses of tooth structure, and (3) detection of calcium (Ca) and fluorine (F) distribution patterns by micro proton-induced X-ray emission (μ-PIXE) and micro proton-induced gamma-ray emission (μ-PIGE) analyses conducted at the Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) at the Takasaki Advanced Radiation Research Institute (TARRI). In this study, the dentin in extracted human molars was exposed by grinding and the dentin was etched with 35% phosphoric acid. Fluoride was applied at two concentrations, 0.022% (100 ppm F) and 2.21% (10,000 ppm F) NaF solution, for two time periods, 30 and 60 s, prior to bonding the resin composite with the treated dentin. Controls were prepared in the same manner, but without the fluoride application. Bond strength was measured with a micro-tensile testing unit, and the fluorine and calcium distributions at the interface between dentin and resin composite were detected by μ-PIGE and μ-PIXE analysis, respectively. Results indicate that the 10,000 ppm F applications resulted in higher bond strengths than observed in either the 100 ppm F applications or the control group. In addition, PIGE analyses showed high concentrations of fluorine in the hybrid bonding layer of the 10,000 ppm F samples, suggesting that the fluorine contributes to the strength of the dentin-resin composite bond. Detection of fluoroapatite within the hybrid bonding layer suggests that bond strength involves remineralization processes.

In-air RBS measurements at the LAMFI external beam setup

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silva, T. F.; Added, N.; Moro, M. V.

2014-11-11

This work describes new developments in the external beam setup of the Laboratory of Material Analysis with Ion Beams of the University of São Paulo (LAMFI-USP). This setup was designed to be a versatile analytical station to analyze a broad range of samples. In recent developments, we seek the external beam Rutherford Backscattering Spectroscopy (RBS) analysis to complement the Particle Induced X-ray Emission (PIXE) measurements. This work presents the initial results of the external beam RBS analysis as well as recent developments to improve the energy resolution RBS measurements, in particular tests to seek for sources of resolution degradation. Thesemore » aspects are discussed and preliminary results of in-air RBS analysis of some test samples are presented.« less

Elemental concentrations in kidney and liver of mice fed with cafeteria or standard diet determined by particle induced X-ray emission

NASA Astrophysics Data System (ADS)

Leffa, Daniela Dimer; dos Santos, Carla Eliete Iochims; Debastiani, Rafaela; Amaral, Livio; Yoneama, Maria Lucia; Dias, Johnny Ferraz; Andrade, Vanessa Moraes

2014-01-01

The importance of trace elements in human health is well known and their main source is daily diet. Nowadays, one of the biggest issues is the presence of these micronutrients in levels much higher than required, leading to potential toxic effects. The aim of this work was to investigate the elemental content in organs of mice fed with cafeteria or standard diet using PIXE. Twelve male Swiss mice were divided into two groups: control group (standard chow) and cafeteria group (high-caloric diet). After 17 weeks, samples of different organs (kidney and liver) were collected and prepared for PIXE analysis. The Fe concentration in kidney and liver was statistically higher in animals that received the cafeteria diet (p < 0.001). The Al and Si kidney contents were significantly higher for cafeteria diet in relation to standard diet (p < 0.05). Moreover, the standard diet showed significant differences for Cl and K (p < 0.05) in comparison to cafeteria diet in kidney, and for P, S and Zn (p < 0.005) in liver.

Silicon Drift Detector response function for PIXE spectra fitting

NASA Astrophysics Data System (ADS)

Calzolai, G.; Tapinassi, S.; Chiari, M.; Giannoni, M.; Nava, S.; Pazzi, G.; Lucarelli, F.

2018-02-01

The correct determination of the X-ray peak areas in PIXE spectra by fitting with a computer program depends crucially on accurate parameterization of the detector peak response function. In the Guelph PIXE software package, GUPIXWin, one of the most used PIXE spectra analysis code, the response of a semiconductor detector to monochromatic X-ray radiation is described by a linear combination of several analytical functions: a Gaussian profile for the X-ray line itself, and additional tail contributions (exponential tails and step functions) on the low-energy side of the X-ray line to describe incomplete charge collection effects. The literature on the spectral response of silicon X-ray detectors for PIXE applications is rather scarce, in particular data for Silicon Drift Detectors (SDD) and for a large range of X-ray energies are missing. Using a set of analytical functions, the SDD response functions were satisfactorily reproduced for the X-ray energy range 1-15 keV. The behaviour of the parameters involved in the SDD tailing functions with X-ray energy is described by simple polynomial functions, which permit an easy implementation in PIXE spectra fitting codes.

Ion beam analysis of ancient Mexican colored teeth from archaeological sites in Mexico City

NASA Astrophysics Data System (ADS)

Rodríguez-Fernández, L.; Ruvalcaba-Sil, J. L.; Ontalba-Salamanca, M. A.; Román-Berrelleza, J. A.; Gallardo, M. L.; Grimaldi, D. M.; de Lucio, O. G.; Miranda, J.

1999-04-01

Infant teeth with extremely rare colored enamel regions white, blue-gray and brown, have been analyzed by Particle Induced X-ray Emission (PIXE) and Rutherford Backscattering Spectrometry (RBS). The teeth were part of human being sacrifices to deities of the Mexica culture, Mexico, corresponding to the Late Post-classic period (1325-1521 A.D.). Comparisons to normal teeth from the same historical period indicate that the colored ones present larger mean amounts of Mn and Fe, while Zn and Sr do not differ too much. Possible inorganic compounds responsible for the different colorations are indicated.

betaPIX controls cell motility and neurite extension by regulating the distribution of GIT1.

PubMed

Za, Lorena; Albertinazzi, Chiara; Paris, Simona; Gagliani, Mariacristina; Tacchetti, Carlo; de Curtis, Ivan

2006-07-01

Cell motility entails the reorganization of the cytoskeleton and membrane trafficking for effective protrusion. GIT1/p95-APP1 is a member of a family of GTPase-activating proteins for ARF GTPases that affect endocytosis, adhesion and migration. GIT1 associates with paxillin and a complex including the Rac/Cdc42 exchanging factors PIX/Cool and the kinase PAK. In this study, we show that overexpression of betaPIX induces the accumulation of endogenous and overexpressed GIT1 at large structures similar to those induced by an ArfGAP-defective mutant of GIT1 (p95-C2). Immunohistochemical analysis and immunoelectron microscopy reveal that these structures include the endogenous transferrin receptor. Time-lapse analysis during motogenic stimuli shows that the formation and perinuclear accumulation of the p95-C2-positive structures is paralleled by inhibition of lamellipodium formation and cell retraction. Both dimerization and a functional SH3 domain of betaPIX are required for the accumulation of GIT1 in fibroblasts, which is prevented by the monomeric PIX-PG-DeltaLZ. This mutant also prevents the formation of endocytic aggregates and inhibition of neurite outgrowth in retinal neurons expressing p95-C2. Our results indicate that betaPIX is an important regulator of the subcellular distribution of GIT1, and suggest that alteration in the level of expression of the complex affects the endocytic compartment and cell motility.

In-air PIXE analysis by means of glass capillary optics

NASA Astrophysics Data System (ADS)

Nebiki, Takuya; Kabir, M. Hasnat; Narusawa, Tadashi

2006-08-01

A novel technique to introduce high energy ion beams to atmospheric environment is presented, which enables in-air PIXE measurements. Slightly tapered glass capillary optics is applied to work as a differential pumping orifice as well as a focusing lens. The flux intensity is enhanced by at least one order of magnitude due to the focusing effect. Using capillaries of 10-20 μm outlet diameters, we obtain several hundreds pA of 4 MeV He2+ ion beam and apply it to PIXE analysis of the seabed sludge without any sample treatments. A comparison of spectra between wet and dry sludge samples suggests the usefulness of our new technique.

A new ion beam facility based on a 3 MV Tandetron™ at IFIN-HH, Romania

NASA Astrophysics Data System (ADS)

Burducea, I.; Straticiuc, M.; Ghiță, D. G.; Moșu, D. V.; Călinescu, C. I.; Podaru, N. C.; Mous, D. J. W.; Ursu, I.; Zamfir, N. V.

2015-09-01

A 3 MV Tandetron™ accelerator system has been installed and commissioned at the "Horia Hulubei" National Institute for Physics and Nuclear Engineering - IFIN-HH, Măgurele, Romania. The main purpose of this machine is to strengthen applied nuclear physics research ongoing in our institute for more than four decades. The accelerator system was developed by High Voltage Engineering Europa B.V. (HVE) and comprises three high energy beam lines. The first beam line is dedicated to ion beam analysis (IBA) techniques: Rutherford Backscattering Spectrometry - RBS, Nuclear Reaction Analysis - NRA, Particle Induced X-ray and γ-ray Emission - PIXE and PIGE and micro-beam experiments - μ-PIXE. The second beam line is dedicated to high energy ion implantation experiments and the third beam line was designed mainly for nuclear cross-sections measurements used in nuclear astrophysics. A unique feature, the first time in operation at an accelerator facility is the Na charge exchange canal (CEC), which is used to obtain high intensity beams of He- of at least 3 μA. The results of the acceptance tests demonstrate the huge potential of this new facility in various fields, from IBA to radiation hardness studies and from medical or environmental applications to astrophysics. The main features of the accelerator are presented in this paper.

Heterogeneous intratumoral distribution of gadolinium nanoparticles within U87 human glioblastoma xenografts unveiled by micro-PIXE imaging.

PubMed

Carmona, Asuncion; Roudeau, Stéphane; L'Homel, Baptiste; Pouzoulet, Frédéric; Bonnet-Boissinot, Sarah; Prezado, Yolanda; Ortega, Richard

2017-04-15

Metallic nanoparticles have great potential in cancer radiotherapy as theranostic drugs since, they serve simultaneously as contrast agents for medical imaging and as radio-therapy sensitizers. As with other anticancer drugs, intratumoral diffusion is one of the main limiting factors for therapeutic efficiency. To date, a few reports have investigated the intratumoral distribution of metallic nanoparticles. The aim of this study was to determine the quantitative distribution of gadolinium (Gd) nanoparticles after direct intratumoral injection within U87 human glioblastoma tumors grafted in mice, using micro-PIXE (Particle Induced X-ray Emission) imaging. AGuIX (Activation and Guiding of Irradiation by X-ray) 3 nm particles composed of a polysiloxane network surrounded by gadolinium chelates were used. PIXE results indicate that the direct injection of Gd nanoparticles in tumors results in their heterogeneous diffusion, probably related to variations in tumor density. All tumor regions contain Gd, but with markedly different concentrations, with a more than 250-fold difference. Also Gd can diffuse to the healthy adjacent tissue. This study highlights the usefulness of mapping the distribution of metallic nanoparticles at the intratumoral level, and proposes PIXE as an imaging modality to probe the quantitative distribution of metallic nanoparticles in tumors from experimental animal models with micrometer resolution. Copyright © 2017 Elsevier Inc. All rights reserved.

A Detailed Analysis of Aerosols Containing Zn, Pb, and Cl from an Industrial Region of Mexico City

NASA Astrophysics Data System (ADS)

Moffet, R. C.; Desyaterik, Y.; Hopkins, R. J.; Tivanski, A. V.; Gilles, M. K.; Shutthanandan, V.; Molina, L. T.; Gonzalez-Abraham, R.; Johnson, K. S.; Mugica, V.; Molina, M. J.; Laskin, A.; Prather, K. A.

2008-12-01

Measurements in the Northern Mexico City Metropolitan Area during the March, 2006 MILAGRO campaign revealed the frequent appearance of particles with a characteristically high content of internally mixed Zn, Pb, Cl, and P. A detailed analysis of the chemical and physical properties of these particles was performed using a complementary combination of aerosol measurement techniques. Single particles were analyzed using Aerosol Time-of-Flight Mass Spectrometry (ATOFMS) and Computer Controlled Scanning Electron Microscopy/Energy Dispersive X-Ray spectroscopy (CCSEM/EDX). Proton Induced X-Ray Emission (PIXE) analysis of bulk aerosol samples provided time-resolved mass concentrations of individual elements. The PIXE measurements indicated that Zn is more strongly correlated with Cl than with any other element and that Zn concentrations are higher than other non-ferrous transition metals. The Zn- and Pb - containing particles have both spherical and non-spherical morphologies. Many metal rich particles had needle-like structures and were found to be composed of ZnO and/or Zn(NO3)2-6H2O as indicated by scanning transmission x-ray microscopy/near edge X-ray absorption spectroscopy (STXM/NEXAFS). The Zn and Pb rich particles were primarily in the submicron size range and internally mixed with elemental carbon. The unique chemical associations most closely match signatures acquired for garbage incineration.

Separation of detector non-linearity issues and multiple ionization satellites in alpha-particle PIXE

NASA Astrophysics Data System (ADS)

Campbell, John L.; Ganly, Brianna; Heirwegh, Christopher M.; Maxwell, John A.

2018-01-01

Multiple ionization satellites are prominent features in X-ray spectra induced by MeV energy alpha particles. It follows that the accuracy of PIXE analysis using alpha particles can be improved if these features are explicitly incorporated in the peak model description when fitting the spectra with GUPIX or other codes for least-squares fitting PIXE spectra and extracting element concentrations. A method for this incorporation is described and is tested using spectra recorded on Mars by the Curiosity rover's alpha particle X-ray spectrometer. These spectra are induced by both PIXE and X-ray fluorescence, resulting in a spectral energy range from ∼1 to ∼25 keV. This range is valuable in determining the energy-channel calibration, which departs from linearity at low X-ray energies. It makes it possible to separate the effects of the satellites from an instrumental non-linearity component. The quality of least-squares spectrum fits is significantly improved, raising the level of confidence in analytical results from alpha-induced PIXE.

Pixe analysis of trace elements in tissues of rats treated with anticonvulsants

NASA Astrophysics Data System (ADS)

Hurd, R. W.; Van Rinsvelt, H. A.; Kinyua, A. M.; O'Neill, M. P.; Wilder, B. J.; Houdayer, A.; Hinrichsen, P. F.

1987-04-01

Several lines of evidence implicate metals in epilepsy. Anticonvulsant drugs are noted to alter levels of metals in humans and animals. PIXE analysis was used to investigate effects of three anticonvulsant drugs on tissue and brain cortex trace elements. The content of zinc and copper was increased in liver and spleen of rats treated with anticonvulsants while selenium was decreased in cortex.

Obsidian provenance determination by using the beam stability controlled BSC-XRF and the PIXE-alpha portable spectrometers of the LANDIS laboratory of the LNS-INFN and IBAM-CNR in Catania (Italy)

NASA Astrophysics Data System (ADS)

Pappalardo, L.; Bracchitta, D.; Palio, O.; Pappalardo, G.; Rizzo, F.

2012-04-01

About 1300 obsidian artefacts coming from various archaeological sites of Sicily were analyzed by using the BSC-XRF (Beam Stability Controlled - X-ray Fluorescence) and PIXE-alpha (Particle Induced X-ray Emission, using low energy alpha particles) portable spectrometers developed at the Landis laboratory at the LNS-INF and IBAM-CNR in Catania (Italy). The portable BSC-XRF system allows the non-destructive analysis of the Rb, Sr, Y, Zr and Nb trace concentrations, which are considered to be characteristic of the obsidian samples and consequently are indicative of the provenance quarries. Quantitative data on Rb, Sr, Y, Zr, Nb trace element concentrations where deduced through the use of a method that makes use of a multi parameter linear regression, previously The portable PIXE-alpha spectrometer allows the quantitative determination of the matrix major elements, from Na to Zn. In the present work the two instrumental devices are presented. The data are from: Milena (Cl), Ustica (Pa), Rocchicella (Ct), Poggio dell'Acquila (Ct), San Marco (Ct), Villaggio del Petraro* (Sr) and Licodia Eubea* (Ct). Results on compositional data for trace elements and major elements allowed to identify Lipari and Pantelleria islands as the only two sources of the analysed samples. Analyses carried out on vitreous artefact found in Rocchicella, showed for the first time that the Palagonite was used as row material. *Preliminary data. Topic of conference: Application of XRS in archaeometry Kind of presentation: oral

PIXE analysis of ancient Chinese Qing dynasty porcelain

NASA Astrophysics Data System (ADS)

Cheng, Huansheng; He, Wenquan; Tang, Jiayong; Yang, Fujia; Wang, Jianhua

1996-09-01

The major and minor chemical compositions and trace element content of white glaze made in Qing dynasty at kuan kiln have been determined by PIXE. Experimental results show that trace element contents RbSrZr are useful to distinguish the place of production of ancient porcelain. In the porcelain from different kilns situated in a same province, the trace element contents can be different from each other. Determining and comparing the major and minor compositions and trace elemental concentrations in white glaze by PIXE technique, we can distinguish a precious Qing dynasty porcelain made at kuan kiln from a fake.

Trace element fingerprinting of jewellery rubies by external beam PIXE

NASA Astrophysics Data System (ADS)

Calligaro, T.; Poirot, J.-P.; Querré, G.

1999-04-01

External beam PIXE analysis allows the non-destructive in situ characterisation of gemstones mounted on jewellery pieces. This technique was used for the determination of the geographical origin of 64 rubies set on a high-valued necklace. The trace element content of these gemstones was measured and compared to that of a set of rubies of known sources. Multivariate statistical processing of the results allowed us to infer the provenance of rubies : one comes from Thailand/Cambodia deposit while the remaining are attributed to Burma. This highlights the complementary capabilities of PIXE and conventional gemological observations.

Analysis of Atmospheric Aerosols Collected in an Urban Area in Upstate NY Using Proton Induced X-ray Emission (PIXE) Spectroscopy

NASA Astrophysics Data System (ADS)

Smith, Jeremy; Ali, Salina; Nadareski, Benjamin; Safiq, Alexandrea; Yoskowitz, Joshua; Labrake, Scott; Vineyard, Michael

2013-10-01

We examined atmospheric aerosol samples collected in Schenectady NY for evidence of pollution. We collected aerosol samples using a nine stage cascade impactor which distributes the particulate matter by aerodynamic size onto 7.5 μm Kapton foils. We then used a 1MV electrostatic Pelletron accelerator to produce a 2.2 MeV proton beam to hit the impacted foils. X-ray intensity versus energy spectra were collected using an Amptek x-ray detector where the x-rays are produced from the proton beam interacting with the sample. This is called PIXE. The elemental composition and concentrations of the elements present in the aerosol samples were determined using a software package called GUPIX. We have found elements ranging from Al to Pb and in particular have found significant amounts of Pb and Br on some of our impacted foils, with a Br/Pb ratio of 0.6 +/- 0.2 which agrees with previous studies. This result suggests the presence of leaded aviation fuel perhaps due to the proximity of the collection site to a small airport with a significant amount of general aviation traffic. Union College.

Measurement of trace elements in tree rings using the PIXE method

NASA Astrophysics Data System (ADS)

Aoki, Toru; Katayama, Yukio; Kagawa, Akira; Koh, Susumu; Yoshida, Kohji

1998-03-01

Standard materials were prepared in order to calculate element concentrations in tree samples using the particle induced X-ray emission (PIXE) method. Five standard solutions (1) Ti, Fe, Cu, As, Rb, Sr; (2) Ca, V, Co, Zn, As, Rb; (3) Ti, Mn, Ni, As, Sr; (4) K, Mn, Co, As, Rb, Sr; and (5) Ca, Mn, Cu, As, Rb, Sr, were added to filter papers. The dried filter papers were used as standard samples. Pellets of Pepperbush leaves (National Institute for Environmental Studies (NIES)) and Peach leaves (National Institute of Standards and Technology (NIST)) were used as references. The peak counts of Ca, Mn, Cu, Zn, Rb, and Sr in samples taken from a kaki ( Diospros kaki Thunb.) were measured and the concentrations (ppm) of the elements were calculated using the yield curve obtained from the standard filter papers. The concentrations of Mn, Zn, Rb, and Ca were compared with the data obtained from a separate INAA analysis. Concentrations of Mn, Zn, and Ca obtained by both methods were almost the same, but the concentrations of Rb differed slightly. The amounts of trace elements in samples taken from a sugi ( Cryptomeria japonica D. Don) were also measured.

Trace elemental analysis of bituminuos coals using the Heidelberg proton microprobe

USGS Publications Warehouse

Chen, J.R.; Kneis, H.; Martin, B.; Nobiling, R.; Traxel, K.; Chao, E.C.T.; Minkin, J.A.

1981-01-01

Trace elements in coal can occur as components of either the organic constituents (macerals) or the inorganic constituents (minerals). Studies of the concentrations and distribution of the trace elements are vital to understanding the geochemical millieu in which the coal was formed and in evaluating the attempts to recover rare but technologically valuable metals. In addition, information on the trace element concentrations is important in predicting the environmental impact of burning particular coals, as many countries move toward greater utilization of coal reserves for energy production. Traditionally, the optical and the electron microscopes and more recently the electron microprobe have been used in studying the components of coal. The proton-induced X-ray emission (PIXE) microprobe offers a new complementary approach with an order of magnitude or more better minimum detection limit. We present the first measurements with a PIXE microprobe of the trace element concentrations of bituminous coal samples. Elemental analyses of the coal macerals-vitrinite, exinite, and inertinite-are discussed for three coal samples from the Eastern U.S.A., three samples from the Western U.S.A., and one sample from the Peoples Republic of China. ?? 1981.

Structural and Functional Studies of the Protamine 2-Zinc Complex from Syrian Gold Hamster (Mesocricetus Auratus) Spermatids and Sperm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolan, Cheryl E.

The research described in this dissertation consists of four major areas: (1) sequence analysis of protamine 2 from Muroid rodents to identify potential zinc-binding domain(s) of protamine 2; (2) structural studies of the protamine 2-zinc complex from Syrian Gold hamster sperm and spermatids to elucidate the role of zinc during spermiogenesis; (3) structural studies of an unique protamine 2-zinc complex from chinchilla sperm; and (4) Nuclear Magnetic Resonance (NMR) studies of soluble complexes of hairpin oligonucleotides with synthetic arginine-rich peptides or protamine 1 isolated from bull sperm. First, zinc was quantitated in spermatids and sperm by Proton-Induced X-ray Emission (PIXE)more » to determine whether zinc is present in the early stages of spermiogenesis. The PIXE results revealed the zinc content varies proportionately with the amount of protamine 2 in both spermatid and sperm nuclei. An exception was chinchilla sperm containing twice the amount of protamine 2 than zinc. Further analyses by PIXE and X-ray Absorption Spectroscopy (XAS) of zinc bound to protamines isolated from hamster sperm confirmed the majority of the zinc is bound to protamine and identified the zinc ligands of protamine 2 in hamster spermatids and sperm in vivo. These studies established that zinc is bound to the protamine 2 precursor in hamster spermatids and the coordination of zinc by protamine 2 changes during spermiogenesis. Finally, the sequence analysis combined with the XAS results suggest that the zinc-binding domain in protamine 2 resides in the amino-terminus. Similar analyses of chinchilla sperm by XAS were performed to clarify the unusual PIXE results and revealed that chinchilla has an atypical protamine 2-zinc structure. Two protamine 2 molecules coordinate one zinc atom, forming homodimers that facilitate the binding of protamine 2 to DNA and provide an organizational scheme that would accommodate the observed species-specific protamine stoichiometry in mammalian sperm. Based on these results, we propose the binding of zinc to protamine 2 molecules stabilizes a dimerization domain in other mammalian sperm. Future experiments will use the knowledge we gained of the interactions between protamine 1 and DNA from the NMR studies to obtain structural data for the DNA-protamine 2-zinc complex.« less

Genetics of the Blue Light-Dependent Signal Cascade That Controls Phototaxis in the Cyanobacterium Synechocystis sp. PCC6803.

PubMed

Sugimoto, Yuki; Nakamura, Hiroshi; Ren, Shukun; Hori, Koichi; Masuda, Shinji

2017-03-01

The Synechocystis sp. PCC6803 can move on a solid surface in response to light, a phenomenon called phototaxis. Although many of the photoreceptors involved in phototaxis have been identified, the mechanisms that regulate directional motility of Synechocystis are not well understood. Previous studies showed that a mutant lacking the blue light-using flavin (BLUF) photoreceptor PixD exhibits negative phototaxis under conditions where the wild type responds positively. PixD interacts with the pseudo-response regulator-like protein PixE in a light-dependent manner, suggesting that this intermolecular interaction is important for phototaxis regulation, although genetic evidence has been lacking. To gain further insight into phototaxis regulation by PixD-PixE signaling, we constructed the deletion mutants ΔPixE and ΔPixD-ΔPixE, and characterized their phenotypes, which matched those of the wild type (positive phototaxis). Because ΔPixD exhibited negative phototaxis, PixE must function downstream of PixD. Under intense blue light (>100 μmol m-2 s-1; 470 nm) the wild type exhibited negative phototaxis, but ΔPixD-PixE exhibited positive phototaxis toward low-intensity blue light (∼0.8 μmol m-2 s-1; 470 nm). These results suggest that an unknown light-sensing system(s), that is necessary for directional cell movement, can be activated by low-intensity blue light; on the other hand, PixD needs high-intensity blue light to be activated. We also isolated spontaneous mutants that compensated for the pixE deletion. Genome-wide sequencing of the mutants revealed that the uncharacterized gene sll2003 regulates positive and negative phototaxis in response to light intensity. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

The hoard of Beçin—non-destructive analysis of the silver coins

NASA Astrophysics Data System (ADS)

Rodrigues, M.; Schreiner, M.; Mäder, M.; Melcher, M.; Guerra, M.; Salomon, J.; Radtke, M.; Alram, M.; Schindel, N.

2010-05-01

We report the results of an analytical investigation on 416 silver-copper coins stemming from the Ottoman Empire (end of 16th and beginning of 17th centuries), using synchrotron micro X-ray fluorescence analysis (SRXRF). In the past, analyses had already been conducted with energy dispersive X-ray fluorescence analysis (EDXRF), scanning electron microscopy with energy dispersive X-ray spectrometry (SEM/EDX) and proton induced X-ray emission spectroscopy (PIXE). With this combination of techniques it was possible to confirm the fineness of the coinage as well as to study the provenance of the alloy used for the coins. For the interpretation of the data statistical analysis (principal component analysis—PCA) has been performed. A definite local assignment was explored and significant clustering was obtained regarding the minor and trace elements composing the coin alloys.

Fluorine uptake into the human enamel surface from fluoride-containing sealing materials during cariogenic pH cycling

NASA Astrophysics Data System (ADS)

Yasuhiro, Matsuda; Katsushi, Okuyama; Hiroko, Yamamoto; Hisanori, Komatsu; Masashi, Koka; Takahiro, Sato; Naoki, Hashimoto; Saiko, Oki; Chiharu, Kawamoto; Hidehiko, Sano

2015-04-01

To prevent the formation of caries and reduce dentin hypersensitivity, sealing materials, either with or without fluoride, are generally applied on the tooth in clinical practice. Application of fluoride-free sealing materials results in the formation of an acid-resistant layer on the tooth surface. On the other hand, fluoride-containing sealing materials might not only form an acid-resistant layer but could possibly further provide fluoride to enhance remineralization and reduce demineralization. In this study, the demineralization prevention ability and fluorine uptake rate in human enamel of fluoride-containing sealing materials ["MS coats F" (MSF)] and fluoride-free sealing materials ("hybrid coats 2" [HI]) were evaluated using an automatic pH cycling system. Each material was applied to the original tooth surface, the cut surfaces were covered with sticky wax, and the automatic pH-cycling system simulated daily acid changes (pH 6.8-4.5) occurring in the oral cavity for 4 weeks. Caries progression was analyzed using transverse microradiography (TMR) taken pre and post the 4 weeks of pH cycling. The fluorine and calcium distributions in the carious lesion in each specimen were evaluated using the proton-induced gamma emission (PIGE) and proton-induced X-ray (PIXE) techniques, respectively. TMR analysis showed that both MSF and HI had a caries-preventing effect after 4 weeks of pH cycling. PIGE/PIXE analysis demonstrated that only MSF resulted in fluoride uptake in the enamel surface. Therefore, MSF can help to form an acid-resistant layer and provide fluoride to the enamel surface. The presence of fluoride on the enamel surface suggested that MSF could prevent demineralization, even if the acid-resistant layer was removed, in clinical settings. The data obtained using the PIGE and PIXE techniques are useful for understanding the benefits of the use of a fluoride-containing sealing material for preventing caries.

Elemental composition and sources of fine and ultrafine ambient particles in Erfurt, Germany.

PubMed

Cyrys, J; Stölzel, M; Heinrich, J; Kreyling, W G; Menzel, N; Wittmaack, K; Tuch, T; Wichmann, H-Erich

2003-04-15

We present the first results of a source apportionment for the urban aerosol in Erfurt, Germany, for the period 1995-1998. The analysis is based on data of particle number concentrations (0.01-2.5 microm; mean 1.8 x 10(4) cm(-3), continuous), the concentration of the ambient gases SO(2), NO, NO(2) and CO (continuous), particle mass less than 2.5 microm (PM(2.5)) and less than 10 microm (PM(10)) (Harvard Impactor sampling, mean PM(2.5) 26.3 micro/m(3), mean PM(10) 38.2 microg/m(3)) and the size fractionated concentrations of 19 elements (impactor sampling 0.05-1.62 microm, PIXE analysis). We determined: (a) the correlations between (i) the 1- and 24-h average concentrations of the gaseous pollutants and the particle number as well as the particle mass concentration and (ii) between the 24-h elemental concentrations; (b) Crustal Enrichment Factors for the PIXE elements using Si as reference element; and (c) the diurnal pattern of the measured pollutants on weekdays and on weekends. The highly correlated PIXE elements Si, Al, Ti and Ca having low enrichment factors were identified as soil elements. The strong correlation of particle number concentrations with NO, which is considered to be typically emitted by traffic, and the striking similarity of their diurnal variation suggest that a sizable fraction of the particle number concentration is associated with emission from vehicles. Besides NO and particle number concentrations other pollutants such as NO(2), CO as well as the elements Zn and Cu were strongly correlated and appear to reflect motor vehicle traffic. Sulfur could be a tracer for coal combustion, however, it was not correlated with any of the quoted elements. Highly correlated elements V and Ni have similar enrichment factors and are considered as tracers for oil combustion.

Determination of Hg concentration in gases by PIXE

NASA Astrophysics Data System (ADS)

Dutkiewicz, E.; van Kuijen, W. J. P.; Munnik, F.; Mutsaers, P. H. A.; Rokita, E.; de Voigt, M. J. A.

1992-05-01

A method for determination of the concentration of mercury in the gaseous phase is described. In the first step of the method a stable sulphur-mercury complex is formed. For this purpose sulphur is deposited on a filter and the investigated gas flows through the filter. Millipore filters and the deposition of sulphur from Na2S2O3 * 5H2O solution were found to be most suitable. The amount of Hg absorbed on the filter was determined by PIXE or by NAA in the second step of the method. An optimization of proton energy was performed in the PIXE analysis to obtain the maximal signal-to-background ratio. The detection limit of the method, expressed as the minimal amount of Hg which has to flow through the filter equals to 30 and 2 ng for PIXE and NAA techniques, respectively. Applications of the method are also described.

Simultaneous quantification of amoxicillin and potassium clavulanate in different commercial drugs using PIXE technique

NASA Astrophysics Data System (ADS)

Bejjani, A.; Roumié, M.; Akkad, S.; El-Yazbi, F.; Nsouli, B.

2016-03-01

We have demonstrated, in previous studies that Particle Induced X-ray Emission (PIXE) is one of the most rapid and accurate choices for quantification of an active ingredient, in a solid drug, from the reactions induced on its specific heteroatom using pellets made from original tablets. In this work, PIXE is used, for the first time, for simultaneous quantification of two active ingredients, amoxicillin trihydrate and potassium clavulanate, in six different commercial antibiotic type of drugs. Since the quality control process of a drug covers a large number of samples, the scope of this study was also to found the most rapid and low cost sample preparation needed to analyze these drugs with a good precision. The chosen drugs were analyzed in their tablets' "as received" form, in pellets made from the powder of the tablets and also in pellets made from the powder of the tablets after being heated up to 70 °C to avoid any molecular destruction until constant weight and removal of humidity. The quantification validity related to the aspects of each sample preparation (homogeneity of the drug components and humidity) are presented and discussed.

Non-invasive quantitative micro-PIXE-RBS/EBS/EBS imaging reveals the lost polychromy and gilding of the Neo-Assyrian ivories from the Louvre collection.

PubMed

Albéric, Marie; Müller, Katharina; Pichon, Laurent; Lemasson, Quentin; Moignard, Brice; Pacheco, Claire; Fontan, Elisabeth; Reiche, Ina

2015-05-01

Antique objects are known to have been brightly colored. However, the appearance of these objects has changed over time and paint traces are rarely preserved. The surface of ivory objects (8th century B.C., Syria) from the Louvre museum collection (Paris) have been non-invasively studied by simultaneous particle-induced X-ray emission (PIXE) and Rutherford and elastic backscattering spectrometry (RBS/EBS) micro-imaging at the AGLAE facility (C2RMF, Paris). Qualitative 2D chemical images of elements ranging from Na to Pb on the surface of the ancient ivory carvings provide evidence of lost polychromy and gilding. Quantitative PIXE data of specific areas allow discrimination between traces of sediments and former polychromy. Different shades of blue can be differentiated from particular Pb/Cu ratios. The characterization of gilding based on RBS data demonstrates the exceptional technological skills of the Phoenician craftsmen supposed to have carved the Arslan Tash ivories. More precise reconstructions of the original polychromy compared to previous studies and a criterion for the authentication of ancient gilded ivory object are proposed. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterisation of zinc in slags originated from a contaminated sediment by coupling /μ-PIXE, /μ-RBS, /μ-EXAFS and powder EXAFS spectroscopy

NASA Astrophysics Data System (ADS)

Isaure, M. P.; Laboudigue, A.; Manceau, A.; Sarret, G.; Tiffreau, C.; Trocellier, P.

2001-07-01

Depositing dredged sediments on soils is usual but it is a hazardous practice for the local environment when these sediments are polluted by heavy metals. This chemical hazard can be assessed by determining the speciation of metals. In this study, slags highly polluted with Zn and originated from a contaminated dredged sediment were investigated. Zn speciation was studied by laterally resolved techniques such as μ-particle induced X-ray emission (μ-PIXE), μ-Rutherford backscattering spectrometry (μ-RBS), μ-extended X-ray absorption fine structure (μ-EXAFS), and bulk analyses such as powder EXAFS spectroscopy. μ-PIXE and μ-RBS results showed that high concentrations of Zn were associated with S in localised areas at the surface of the slags while moderate amounts of Zn were mainly associated with Fe in the matrix. EXAFS results allowed to identify ZnS and Zn sorbed on ferrihydrite (5Fe 2O 3·9H 2O), proxy for iron oxy-hydroxides, as the main Zn-bearing phases. The occurrence of this Zn-iron oxy-hydroxide is interpreted as a mobilisation of Zn released from ZnS oxidation.

An attempt to diagnose cancer by PIXE

NASA Astrophysics Data System (ADS)

Uda, M.; Maeda, K.; Sasa, Y.; Kusuyama, H.; Yokode, Y.

1987-03-01

PIXE is suitable especially for trace elemental analysis for atoms with high atomic numbers, which are contained in matrices composed mainly of light elements such as biological materials. An attempt has been made to distinguish elemental concentrations of cancer tissues from those of normal ones. Kidney, testis and urinary bladder cancer tissues were examined by PIXE. Key elements to diagnose these cancers were Ca, Ti, Cr, Fe and Zn. Enrichment of Fe and Ti, and deficiency of Zn could be seen in the kidney cancer. An opposite tendency was observed in the testicular cancer. Imbalance of these elemental concentrations in characteristic organs might give us a possibility for cancer diagnosis.

PIXE analysis of Chinese ancient greenish white porcelain

NASA Astrophysics Data System (ADS)

Cheng, Lin; Ding, Xun-liang; Feng, Song-lin; Cheng, Huang-sheng; Zhang, Wen-Jiang; Fan, Chang-Sheng

2006-03-01

This paper reports the results about the PIXE analysis of major, minor and trace elements of Chinese ancient greenish white porcelain and blue-and-white porcelain produced in Hutian Kiln (Jingdezhen district, Jiangxi province) during 10th-14th centuries. The porcelain body and greenish white glaze from northern Song (AD 960), southern Song (AD 1037-1276), early Yuan (AD 1279-1320), later Yuan (AD 1320-1368) were investigated together with white-and-blue glaze from Ming dynasty (AD 1368-1644). The obtained data were further analyzed by factor analysis.

Biomedical studies by PIXE

NASA Astrophysics Data System (ADS)

Afarideh, H.; Amirabadi, A.; Hadji-Saeid, S. M.; Mansourian, N.; Kaviani, K.; Zibafar, E.

1996-04-01

In the present biomedical research, PIXE a powerful technique for elemental analysis was employed to illustrate the importance of multi-elemental determination of serum trace elements in two cases of great medical interest. Those are evaluation of the desferroxamine drug (DPO), a widely used therapy for patient with β-thalassemia-Major (β-thal-M), and investigation of elemental variations in blood-serum in hyperbilirubinamia new-borns before and after blood transfusion (BT). The purpose of the work is to demonstrate the various aspects of PIXE analysis by some practical examples as well as to draw some general conclusions regarding the cure of those patients with the above mentioned disorders or diseases. To present in details each case, we divide the paper in two parts: part 1 and part 2 to consider the experimental procedure as well as the results individually.

Quantitative analysis of major elements in silicate minerals and glasses by micro-PIXE

USGS Publications Warehouse

Campbell, J.L.; Czamanske, G.K.; MacDonald, L.; Teesdale, W.J.

1997-01-01

The Guelph micro-PIXE facility has been modified to accommodate a second Si(Li) X-ray detector which records the spectrum due to light major elements (11 ??? Z ??? 20) with no deleterious effects from scattered 3 MeV protons. Spectra have been recorded from 30 well-characterized materials, including a broad range of silicate minerals and both natural and synthetic glasses. Sodium is mobile in some of the glasses, but not in the studied mineral lattices. The mean value of the instrumental constant H for each of the elements Mg, Al, and Si in these materials is systematically 6-8% lower than the H-value measured for the pure metals. Normalization factors are derived which permit the matrix corrections requisite for trace-element measurements in silicates to be based upon pure metal standards for Mg, Al and Si, supplemented by well-established, silicate mineral standards for the elements Na, K and Ca. Rigorous comparisons of electron microprobe and micro-PIXE analyses for the entire, 30-sample suite demonstrate the ability of micro-PIXE to produce accurate analysis for the light major elements in silicates. ?? 1997 Elsevier Science B.V.

Quantification of lithium at ppm level in geological samples using nuclear reaction analysis.

PubMed

De La Rosa, Nathaly; Kristiansson, Per; Nilsson, E J Charlotta; Ros, Linus; Pallon, Jan; Skogby, Henrik

2018-01-01

Proton-induced reaction (p,α) is one type of nuclear reaction analysis (NRA) suitable especially for light element quantification. In the case of lithium quantification presented in this work, accelerated protons with an energy about of 850 keV were used to induce the 7 Li(p,α) 4 He reaction in standard reference and geological samples such as tourmaline and other Li-minerals. It is shown that this technique for lithium quantification allowed for measurement of concentrations down below one ppm. The possibility to relate the lithium content with the boron content in a single analysis was also demonstrated using tourmaline samples, both in absolute concentration and in lateral distribution. In addition, Particle induced X-ray emission (PIXE) was utilized as a complementary IBA technique for simultaneous mapping of elements heavier than sodium.

Analysis of positional isotope exchange in ATP by cleavage of the beta P-O gamma P bond. Demonstration of negligible positional isotope exchange by myosin.

PubMed

Dale, M P; Hackney, D D

1987-12-15

A method for analysis of positional isotope exchange (PIX) during ATP in equilibrium with HOH oxygen exchange is presented that uses a two-step degradation of ATP resulting in cleavage of the beta P-O gamma P bond. This cleavage yields Pi derived from the gamma-phosphoryl of ATP that contains all four of the gamma oxygens. Both PIX between the beta,gamma-bridge and beta-nonbridge positions and washout of the gamma-nonbridge oxygens can be simultaneously followed by using ATP labeled with 17O at the beta-nonbridge positions and 18O at the beta,gamma-bridge and gamma-nonbridge positions. Application of this method to ATP in equilibrium with HOH exchange during single turnovers of myosin indicates that the bulk of the ATP undergoes rapid washout of gamma-nonbridge oxygens in the virtual absence of PIX. At 25 degrees C with subfragment 1 the scrambling rate is at the limit of detectability of approximately 0.001 s-1, which is 50-fold slower than the steady-state rate. This corresponds to a probability of scrambling for the beta-oxygens of bound ADP of 1 in 10,000 for each cycle of reversible hydrolysis of bound ATP. A fraction of the ATP, however, does not undergo rapid washout. With myosin and stoichiometric ATP at 0 degrees C, this fraction corresponds to 10% of the ATP remaining at 36 s, or 2% of the initial ATP, and an equivalent level of ATP is found that does not bind irreversibly to myosin in a cold chase experiment. A significant level of apparent PIX is observed with subfragment 1 in the fraction that resists washout, and this apparent PIX is shown to be due to contaminant adenylate kinase activity. This apparent PIX due to adenylate kinase provides a possible explanation for the PIX observed by Geeves et al. [Geeves, M. A., Webb, M. R., Midelfort, C. F., & Trentham, D. R. (1980) Biochemistry 19, 4748-4754] with subfragment 1.

Relation between aerosol sources and meteorological parameters for inhalable atmospheric particles in Sao Paulo City, Brazil

NASA Astrophysics Data System (ADS)

Andrade, Fatima; Orsini, Celso; Maenhaut, Willy

Stacked filter units were used to collect atmospheric particles in separate coarse and fine fractions at the Sao Paulo University Campus during the winter of 1989. The samples were analysed by particle-induced X-ray emission (PIXE) and the data were subjected to an absolute principal component analysis (APCA). Five sources were identified for the fine particles: industrial emissions, which accounted for 13% of the fine mass; emissions from residual oil and diesel, explaining 41%; resuspended soil dust, with 28%; and emissions of Cu and of Mg, together with 18%. For the coarse particles, four sources were identified: soil dust, accounting for 59% of the coarse mass; industrial emissions, with 19%; oil burning, with 8%; and sea salt aerosol, with 14% of the coarse mass. A data set with various meteorological parameters was also subjected to APCA, and a correlation analysis was performed between the meteorological "absolute principal component scores" (APCS) and the APCS from the fine and coarse particle data sets. The soil dust sources for the fine and coarse aerosol were highly correlated with each other and were anticorrelated with the sea breeze component. The industrial components in the fine and coarse size fractions were also highly positively correlated. Furthermore, the industrial component was related with the northeasterly wind direction and, to a lesser extent, with the sea breeze component.

Tang dynasty (618-907) bowl measured with PIXE

NASA Astrophysics Data System (ADS)

Laitinen, M.; Käyhkö, M.; Hahn, G.; von Uexküll-Güldenband, N.; Sajavaara, T.

2017-09-01

Brownish bowl originating from an underwater shipwreck located near Belitung island in the Java Sea, some 600 km south-east from Singapore, has been measured with particle induced X-ray emission. This study was a pilot project for the - now a spin-off company - Recenart research team where one target was to evaluate the authenticity of the different type of art objects. PIXE measurements were done from three different material positions from a single bowl received from a customer. These locations were categorized as a bluish/greenish pigment (under glaze), thick glaze and the body clay. When the obtained data was compared to the other references from different dynasties and kiln sites, the closest match was indeed the Tang dynasty, Tongguan/Ghangsha kiln-site potsherds - from where the bowl in question was also suspected to originate.

αPIX Is a Trafficking Regulator that Balances Recycling and Degradation of the Epidermal Growth Factor Receptor

PubMed Central

Kortüm, Fanny; Harms, Frederike Leonie; Hennighausen, Natascha; Rosenberger, Georg

2015-01-01

Endosomal sorting is an essential control mechanism for signaling through the epidermal growth factor receptor (EGFR). We report here that the guanine nucleotide exchange factor αPIX, which modulates the activity of Rho-GTPases, is a potent bimodal regulator of EGFR trafficking. αPIX interacts with the E3 ubiquitin ligase c-Cbl, an enzyme that attaches ubiquitin to EGFR, thereby labelling this tyrosine kinase receptor for lysosomal degradation. We show that EGF stimulation induces αPIX::c-Cbl complex formation. Simultaneously, αPIX and c-Cbl protein levels decrease, which depends on both αPIX binding to c-Cbl and c-Cbl ubiquitin ligase activity. Through interaction αPIX sequesters c-Cbl from EGFR and this results in reduced EGFR ubiquitination and decreased EGFR degradation upon EGF treatment. However, quantitatively more decisive for cellular EGFR distribution than impaired EGFR degradation is a strong stimulating effect of αPIX on EGFR recycling to the cell surface. This function depends on the GIT binding domain of αPIX but not on interaction with c-Cbl or αPIX exchange activity. In summary, our data demonstrate a previously unappreciated function of αPIX as a strong promoter of EGFR recycling. We suggest that the novel recycling regulator αPIX and the degradation factor c-Cbl closely cooperate in the regulation of EGFR trafficking: uncomplexed αPIX and c-Cbl mediate a positive and a negative feedback on EGFR signaling, respectively; αPIX::c-Cbl complex formation, however, results in mutual inhibition, which may reflect a stable condition in the homeostasis of EGF-induced signal flow. PMID:26177020

Analyses of gold artifacts from Slovenia

NASA Astrophysics Data System (ADS)

Šmit, Ž.; Budnar, M.; Pelicon, P.; Zorko, B.; Knific, T.; Istenič, J.; Trampuž-Orel, N.; Demortier, G.

2000-03-01

The method of particle-induced X-ray emission (PIXE) was used for the study of two gold archaeological finds: a Norico-Pannonian brooch, presumably a votive item, and a pair of earrings and a ring from a Slavic female grave. The analysis was performed by an external proton millibeam and aimed to identify the manufacturing techniques. The brooch, including the spring, was made of a rather pure 98% gold. This may indicate that the brooch was produced for votive purposes, as a more flexible spring would suit an object to be worn. The Slavic ring was made of a different alloy than the earrings; moreover, its inhomogeneous alloy reveals the exploitation of local gold sources.

The Determination of Soil-plant Transfer Coefficients of Cesium-137 and Other Elements by γ-Ray Measurement and PIXE Analysis, for use in the Remediation of Fukushima

NASA Astrophysics Data System (ADS)

Ishii, K.; Fujita, A.; Toyama, S.; Terakawa, A.; Matsuyama, S.; Arai, H.; Osada, N.; Takyu, S.; Matsuyama, T.; Koshio, S.; Watanabe, K.; Ito, S.; Kasahara, K.

Edible wild plants growing in the area around the Fukushima Daiichi nuclear power plant remain contaminated. It is important to identify plants with low levels of contamination for the restoration of agriculture in the area. We collected specimens of 10 wild plant species growing in Iitate village which is one of the most highly contaminated areas and also sampled the soil beneath each plant. We measured the specific activity of 137Cs and the concentrations of Na, Mg, Al, Si, P, S, K, Ca, Fe, Zn, Rb and Sr in these samples using a germanium detector and PIXE analysis, respectively. We compared the soil-plant transfer coefficient of 137Cs with those of each element and determined their correlation with 137Cs. It was found that a low Sr transfer coefficient could be used to determine the plants with a low 137Cs transfer coefficient. We suggest that PIXE analysis is a useful analysis technique for agricultural remediation projects in highly contaminated areas around the Fukushima Daiichi nuclear power plant.

Application of relativistic electrons for the quantitative analysis of trace elements

NASA Astrophysics Data System (ADS)

Hoffmann, D. H. H.; Brendel, C.; Genz, H.; Löw, W.; Richter, A.

1984-04-01

Particle induced X-ray emission methods (PIXE) have been extended to relativistic electrons to induce X-ray emission (REIXE) for quantitative trace-element analysis. The electron beam (20 ≤ E0≤ 70 MeV) was supplied by the Darmstadt electron linear accelerator DALINAC. Systematic measurements of absolute K-, L- and M-shell ionization cross sections revealed a scaling behaviour of inner-shell ionization cross sections from which X-ray production cross sections can be deduced for any element of interest for a quantitative sample investigation. Using a multielemental mineral monazite sample from Malaysia the sensitivity of REIXE is compared to well established methods of trace-element analysis like proton- and X-ray-induced X-ray fluorescence analysis. The achievable detection limit for very heavy elements amounts to about 100 ppm for the REIXE method. As an example of an application the investigation of a sample prepared from manganese nodules — picked up from the Pacific deep sea — is discussed, which showed the expected high mineral content of Fe, Ni, Cu and Ti, although the search for aliquots of Pt did not show any measurable content within an upper limit of 250 ppm.

Study of atmospheric aerosols by IBA techniques: The LABEC experience

NASA Astrophysics Data System (ADS)

Lucarelli, F.; Calzolai, G.; Chiari, M.; Nava, S.; Carraresi, L.

2018-02-01

At the 3 MV Tandetron accelerator of the LABEC laboratory of INFN (Florence, Italy) an external beam facility is fully dedicated to PIXE-PIGE measurements of the elemental composition of atmospheric aerosols. All the elements with Z > 10 are simultaneously detected by PIXE typically in one minute. This setup allows us an easy automatic positioning, changing and scanning of samples collected by different kinds of devices: long series of daily PM (Particulate Matter) samples can be analysed in short times, as well as size-segregated and high time-resolution aerosol samples. Thanks to the capability of detecting all the crustal elements, PIXE-PIGE analyses are unrivalled in the study of mineral dust: consequently, they are very effective in the study of natural aerosols, like, for example, Saharan dust intrusions. Among the detectable elements there are also important markers of anthropogenic sources, which allow effective source apportionment studies in polluted urban environments using a multivariate method like Positive Matrix Factorization (PMF). Examples regarding recent monitoring campaigns, performed in urban and remote areas, both daily and with high time resolution (hourly samples), as well as with size selection, are presented. The importance of the combined use of the Particle Induced Gamma Ray emission technique (PIGE) and of other complementary (non-nuclear) techniques is highlighted.

Pre-Hispanic ceramics analyzed using PIXE and radiographic techniques

NASA Astrophysics Data System (ADS)

Lima, S. C.; Rizzutto, M. A.; Added, N.; Barbosa, M. D. L.; Trindade, G. F.; Fleming, M. I. D. A.

2011-12-01

Ceramics objects are the most common artifacts found during excavation of archaeological sites and often depicts cultural habits and manufacturing technologies of the culture. The determination of macroscopic and microscopic characteristics of the ceramic objects such as the ceramic porosity, addition of tempers in the clay, main chemical components and the trace elements present in the ceramic can reveal many aspects about the manufacturing processes used by the culture, its degree of development, the provenance of the raw materials and the exchange networks. Also the radiography can help to investigate the manufactured processes, the size of the tempers used and the conservation status of the artifacts. In this present work two non-destructive techniques, radiography and PIXE (Particle Induced X-ray Emission) were used to characterize one set of thirty-six pre-Hispanic ceramic pieces from the Chimu Culture conserved in the Museu de Arqueologia e Etnologia (MAE/USP). The PIXE analyses performed in the external beam setup at LAMFI (Laboratório de Análise de Materiais por Feixes Iônicos) allowed measure the principal chemical elements such as Al, Si, K, Ti, Fe and Ca, present in this group of pieces. X-ray imagings allowed identify the manufacture processes, the granularity of the tempers used, as well as the similarity and the differences between the pieces studied.

New approaches for investigating paintings by ion beam techniques

NASA Astrophysics Data System (ADS)

Beck, L.; de Viguerie, L.; Walter, Ph.; Pichon, L.; Gutiérrez, P. C.; Salomon, J.; Menu, M.; Sorieul, S.

2010-06-01

Up to now, among the IBA techniques, only PIXE has been used for analyzing paintings. However, quantitative PIXE analysis is sometimes difficult to interpret due to the layered structure, the presence of varnish and organic binder and, in some cases, discoloration of the pigments has been observed due to the interaction of the ion beam with the compounds. In order to improve the characterization of paintings, we propose some alternative experimental procedures. First of all, backscattering spectrometry (BS) and PIXE are simultaneously combined in order to collect complementary information such as layer thickness and organic compound quantification. The simultaneous PIXE and BS experiments also have the advantage of being able to analyze the same area in one experiment. This combination, implemented with an external beam, was directly applied on paintings and on painting cross-sections for the study of Italian Renaissance masterpieces. We have obtained valuable results not only on the pigment itself but also, for the first time, on the binder to pigment proportion which is not well documented in the ancient recipes. Moreover, in order to restrain beam damages due to the ion stopping power, we propose to analyze very thin painting cross-sections by a combination of PIXE-RBS and Scanning Transmission Ion Microscopy (STIM).

Ion Microbeam Analyses of Dust Particles and Codeposits from JET with the ITER-Like Wall.

PubMed

Fazinić, Stjepko; Tadić, Tonči; Vukšić, Marin; Rubel, Marek; Petersson, Per; Fortuna-Zaleśna, Elżbieta; Widdowson, Anna

2018-05-01

Generation of metal dust in the JET tokamak with the ITER-like wall (ILW) is a topic of vital interest to next-step fusion devices because of safety issues with plasma operation. Simultaneous Nuclear Reaction Analysis (NRA) and Particle-Induced X-ray Emission (PIXE) with a focused four MeV 3 He microbeam was used to determine the composition of dust particles related to the JET operation with the ILW. The focus was on "Be-rich particles" collected from the deposition zone on the inner divertor tile. The particles found are composed of a mix of codeposited species up to 120 μm in size with a thickness of 30-40 μm. The main constituents are D from the fusion fuel, Be and W from the main plasma-facing components, and Ni and Cr from the Inconel grills of the antennas for auxiliary plasma heating. Elemental concentrations were estimated by iterative NRA-PIXE analysis. Two types of dust particles were found: (i) larger Be-rich particles with Be concentrations above 90 at% with a deuterium presence of up to 3.4 at% and containing Ni (1-3 at%), Cr (0.4-0.8 at%), W (0.2-0.9 at%), Fe (0.3-0.6 at%), and Cu and Ti in lower concentrations and (ii) small particles rich in Al and/or Si that were in some cases accompanied by other elements, such as Fe, Cu, or Ti or W and Mo.

Structural and waveguiding characteristics of Er3+:Yb3Al5-yGayO12 films grown by the liquid phase epitaxy

NASA Astrophysics Data System (ADS)

Hlásek, T.; Rubešová, K.; Jakeš, V.; Nekvindová, P.; Kučera, M.; Daniš, S.; Veis, M.; Havránek, V.

2015-11-01

Erbium (Er3+) doped ytterbium garnet (Er:Yb3Al5-yGayO12; y = 0, 0.55 and 1.1) single crystalline thick films have been grown by the low-temperature liquid phase epitaxy method (LPE). The composition of the films was determined using the high resolution XRD, the particle-induced X-ray emission spectroscopy (PIXE) and the particle-induced gamma-ray emission spectroscopy (PIGE). The lattice mismatch between films and substrates was investigated by the high-resolution X-ray diffraction. The surface analysis was carried out by the atomic force microscopy (AFM). Pure infrared emission of Er3+ ions was observed in all films containing gallium. The characteristics such as refractive index, thickness and light propagation were studied by the m-line spectroscopy (MLS) using several wavelengths (633, 964, 1311 and 1552 nm). All samples, where y = 1.1, were multimode waveguides. For these reasons, the Er:Yb3Al3.9Ga1.1O12 seems to be a promising material for light amplifiers in the IR region.

High energy PIXE: A tool to characterize multi-layer thick samples

NASA Astrophysics Data System (ADS)

Subercaze, A.; Koumeir, C.; Métivier, V.; Servagent, N.; Guertin, A.; Haddad, F.

2018-02-01

High energy PIXE is a useful and non-destructive tool to characterize multi-layer thick samples such as cultural heritage objects. In a previous work, we demonstrated the possibility to perform quantitative analysis of simple multi-layer samples using high energy PIXE, without any assumption on their composition. In this work an in-depth study of the parameters involved in the method previously published is proposed. Its extension to more complex samples with a repeated layer is also presented. Experiments have been performed at the ARRONAX cyclotron using 68 MeV protons. The thicknesses and sequences of a multi-layer sample including two different layers of the same element have been determined. Performances and limits of this method are presented and discussed.

Application of micron X-ray CT based on micro-PIXE to investigate the distribution of Cs in silt particles for environmental remediation in Fukushima Prefecture

NASA Astrophysics Data System (ADS)

Ishii, Keizo; Hatakeyama, Taisuke; Itoh, Shin; Sata, Daichi; Ohnuma, Tohru; Yamaguchi, Toshiro; Arai, Hiromu; Arai, Hirotsugu; Matsuyama, Shigeo; Terakawa, Atsuki; Kim, Seong-Yun

2016-03-01

We used X-ray computed tomography (CT) using characteristic X-rays produced in micro-particle-induced X-ray emission (PIXE) to investigate the internal structure of silt particles and develop new methods to decontaminate soil containing radioactive cesium. We obtained 3D attenuation coefficient images of silt particles with a diameter of approximately 100 μm for V K and Cr K X-rays. Owing to the absorption edges of the Cs L-shell, the differences between the V K and Cr K X-ray images revealed the spatial distribution of Cs atoms in the silt particles. Cs atoms were distributed over the surfaces of the silt particles to a thickness of approximately 10 μm. This information is useful for the decontamination of silt contaminated by radiation from the Fukushima Daiichi nuclear disaster.

Elemental composition of PM 10 and PM 2.5 in urban environment in South Brazil

NASA Astrophysics Data System (ADS)

Braga, C. F.; Teixeira, E. C.; Meira, L.; Wiegand, F.; Yoneama, M. L.; Dias, J. F.

The purpose of the present study is to analyze the elemental composition and the concentrations of PM 10 and PM 2.5 in the Guaíba Hydrographic Basin with HV PM 10 and dichotomous samplers. Three sampling sites were selected: 8° Distrito, CEASA and Charqueadas. The sampling was conducted from October 2001 to December 2002. The mass concentrations of the samplers were evaluated, while the elemental concentrations of Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu and Zn were determined using the Particle-Induced X-ray Emission (PIXE) technique. Factor Analysis and Canonical Correlation Analysis were applied to the chemical and meteorological variables in order to identify the sources of particulate matter. Industrial activities such as steel plants, coal-fired power plants, hospital waste burning, vehicular emissions and soil were identified as the sources of the particulate matter. Concentration levels higher than the daily and the annual average air quality standards (150 and 50 μg m -3, respectively) set by the Brazilian legislation were not observed.

c-Cbl regulates αPix-mediated cell migration and invasion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seong, Min Woo; Park, Ji Ho; Yoo, Hee Min

2014-12-12

Highlights: • c-Cbl ubiquitinates αPix for proteasome-mediated degradation. • C6 and A172 glioma cells lack c-Cbl, which leads to stabilization of αPix. • The accumulated αPix promotes migration and invasion of the cancer cells. • The lack of c-Cbl in the cells appears responsible for their malignant behavior. - Abstract: c-Cbl, a RING-type ubiquitin E3 ligase, down-regulates receptor tyrosine kinases, including EGF receptor, and inhibits cell proliferation. Moreover, c-Cbl mutations are frequently found in patients with myeloid neoplasm. Therefore, c-Cbl is known as a tumor suppressor. αPix is expressed only in highly proliferative and mobile cells, including immune cells, andmore » up-regulated in certain invasive tumors, such as glioblastoma multiforme. Here, we showed that c-Cbl serves as an ubiquitin E3 ligase for proteasome-mediated degradation of αPix, but not βPix. Remarkably, the rat C6 and human A172 glioma cells were unable to express c-Cbl, which leads to a dramatic accumulation of αPix. Depletion of αPix by shRNA markedly reduced the ability of the glioma cells to migrate and invade, whereas complementation of shRNA-insensitive αPix promoted it. These results indicate that c-Cbl negatively regulates αPix-mediated cell migration and invasion and the lack of c-Cbl in the C6 and A172 glioma cells is responsible for their malignant behavior.« less

Future of ePix detectors for high repetition rate FELs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blaj, G., E-mail: blaj@slac.stanford.edu; Caragiulo, P.; Carini, G.

2016-07-27

Free-electron lasers (FELs) made the imaging of atoms and molecules in motion possible, opening new science opportunities with high brilliance, ultra-short x-ray laser pulses at up to 120 Hz. Some new or upgraded FEL facilities will operate at greatly increased pulse rates (kHz to MHz), presenting additional requirements on detection. We will present the ePix platform for x-ray detectors and the current status of the ePix detectors: ePix100 for low noise applications, ePix10k for high dynamic range applications, and ePixS for spectroscopic applications. Then we will introduce the plans to match the ePix detectors with the requirements of currently plannedmore » high repetition rate FELs (mainly readout speed and energy range).« less

Endothelin-1 Inhibits the Epithelial Na+ Channel through βPix/14-3-3/Nedd4-2

PubMed Central

Pavlov, Tengis S.; Chahdi, Ahmed; Ilatovskaya, Daria V.; Levchenko, Vladislav; Vandewalle, Alain; Pochynyuk, Oleh

2010-01-01

Epithelial Na+ channels (ENaCs) mediate sodium reabsorption in the cortical collecting duct (CCD), but the regulatory pathways that modulate the activity of these channels are incompletely understood. Here, we observed that endothelin-1 (ET-1) attenuates ENaC activity acutely by reducing the channel's open probability and chronically by decreasing the number of channels in the plasma membrane. To investigate whether β1Pix, a signaling protein activated by ET-1, mediates ENaC activity, we reconstituted ENaC in CHO cells with or without coexpressed β1Pix and found that β1Pix negatively regulates ENaC. Knockdown of βPix in native principal cells abolished the ET-1-induced decrease in ENaC channel number. Furthermore, we found that βPix does not decrease ENaC activity through its guanine nucleotide exchange factor (GEF) activity for Rac1 and Cdc42. Instead, coexpression of β1Pix mutant constructs revealed that β1Pix affects ENaC activity through binding 14-3-3 proteins. Coimmunoprecipitation experiments supported a physical interaction between β1Pix and 14-3-3β in cultured principal cells. Coexpression of 14-3-3β increased ENaC activity in CHO cells, but concomitant expression of β1Pix attenuated this increase. Recruitment of 14-3-3β by β1Pix impaired the interaction of 14-3-3β with the ubiquitin ligase Nedd4-2, thereby promoting ubiquitination and degradation of ENaC. Taken together, these results suggest that the inhibitory effects of chronic ET-1 on ENaC result from βPix interacting with the 14-3-3/Nedd4-2 pathway. PMID:20338996

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hichwa, B.P.; Pun, D.D.; Wang, D.

A multielemental analysis to determine the trace metal content of generic and name-brand aspirins and name-brand lipsticks was done via proton induced x-ray (PIXE) measurements. The Hope College PIXE system is described as well as the target preparation methods. The trace metal content of twelve brands of aspirin and aspirin substitutes and fourteen brands of lipstick are reported. Detection limits for most elements are in the range of 100 parts per billion (ppb) to 10 parts per million (ppm).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Z. J.; Wells, D.; Green, J.

Photon Activation Analysis (PAA) of environmental, archaeological and industrial samples requires extensive data analysis that is susceptible to error. For the purpose of saving time, manpower and minimizing error, a computer program was designed, built and implemented using SQL, Access 2007 and asp.net technology to automate this process. Based on the peak information of the spectrum and assisted by its PAA library, the program automatically identifies elements in the samples and calculates their concentrations and respective uncertainties. The software also could be operated in browser/server mode, which gives the possibility to use it anywhere the internet is accessible. By switchingmore » the nuclide library and the related formula behind, the new software can be easily expanded to neutron activation analysis (NAA), charged particle activation analysis (CPAA) or proton-induced X-ray emission (PIXE). Implementation of this would standardize the analysis of nuclear activation data. Results from this software were compared to standard PAA analysis with excellent agreement. With minimum input from the user, the software has proven to be fast, user-friendly and reliable.« less

DeltaPhage—a novel helper phage for high-valence pIX phagemid display

PubMed Central

Nilssen, Nicolay R.; Frigstad, Terje; Pollmann, Sylvie; Roos, Norbert; Bogen, Bjarne; Sandlie, Inger; Løset, Geir Å.

2012-01-01

Phage display has been instrumental in discovery of novel binding peptides and folded domains for the past two decades. We recently reported a novel pIX phagemid display system that is characterized by a strong preference for phagemid packaging combined with low display levels, two key features that support highly efficient affinity selection. However, high diversity in selected repertoires are intimately coupled to high display levels during initial selection rounds. To incorporate this additional feature into the pIX display system, we have developed a novel helper phage termed DeltaPhage that allows for high-valence display on pIX. This was obtained by inserting two amber mutations close to the pIX start codon, but after the pVII translational stop, conditionally inactivating the helper phage encoded pIX. Until now, the general notion has been that display on pIX is dependent on wild-type complementation, making high-valence display unachievable. However, we found that DeltaPhage does facilitate high-valence pIX display when used with a non-suppressor host. Here, we report a side-by-side comparison with pIII display, and we find that this novel helper phage complements existing pIX phagemid display systems to allow both low and high-valence display, making pIX display a complete and efficient alternative to existing pIII phagemid display systems. PMID:22539265

DeltaPhage--a novel helper phage for high-valence pIX phagemid display.

PubMed

Nilssen, Nicolay R; Frigstad, Terje; Pollmann, Sylvie; Roos, Norbert; Bogen, Bjarne; Sandlie, Inger; Løset, Geir Å

2012-09-01

Phage display has been instrumental in discovery of novel binding peptides and folded domains for the past two decades. We recently reported a novel pIX phagemid display system that is characterized by a strong preference for phagemid packaging combined with low display levels, two key features that support highly efficient affinity selection. However, high diversity in selected repertoires are intimately coupled to high display levels during initial selection rounds. To incorporate this additional feature into the pIX display system, we have developed a novel helper phage termed DeltaPhage that allows for high-valence display on pIX. This was obtained by inserting two amber mutations close to the pIX start codon, but after the pVII translational stop, conditionally inactivating the helper phage encoded pIX. Until now, the general notion has been that display on pIX is dependent on wild-type complementation, making high-valence display unachievable. However, we found that DeltaPhage does facilitate high-valence pIX display when used with a non-suppressor host. Here, we report a side-by-side comparison with pIII display, and we find that this novel helper phage complements existing pIX phagemid display systems to allow both low and high-valence display, making pIX display a complete and efficient alternative to existing pIII phagemid display systems.

PIGE-PIXE analysis of human milk

NASA Astrophysics Data System (ADS)

Olabanji, S. O.; Buoso, M. C.; Ceccato, D.; Haque, A. M. I.; Cherubini, R.; Moschini, G.

1996-04-01

PIGE-PIXE nuclear techniques were employed for the determination of the elemental composition of human breast milk which is the main source of nutrients to babies in Nigeria. Samples were collected from 32 healthy lactating mothers from Obafemi Awolowo Teaching University Hospital, Ile-Ife, Nigeria. The samples were homogenized and immediately frozen, and then freeze-dried. Pellets were made using a Perkin Elmer instrument and its accessory the 13 mm die. PIGE measurements of light elements were performed using 3.5 MeV collimated protons from the 7 MV CN Van de Graaff accelerator of INFN, LNL, Legnaro (Padova) Italy while PIXE analysis was carried out using 1.8 MeV collimated proton beam from the 2.5 MV AN 2000 Van de Graaff accelerator of the same Institute. The results show the presence of important elements that are essential for growth and development of babies. We searched for certain toxic elements which include As, Cd, Hg, Pb, etc. because of their negative roles in enhancing infant mortality rates, but none of them was detected except Pb.

Usewear studies of flint tools with microPIXE and microRBS

NASA Astrophysics Data System (ADS)

Christensen, Marianne; Grime, Geoff; Menu, Michel; Walter, Philippe

1993-05-01

The use of ancient stone tools leaves a polish (usewear) on the cutting edge which can be studied to determine the material the tool had worked during its use. The film is formed by high pressure intrusion of the worked material into the microcavities of the chipped flint surface and so the film can also be analysed directly to determine the nature of the worked material. This paper describes the analysis of experimental flint tools which had worked bone and ivory using microbeam PIXE and RBS. It is found that PIXE used simultaneously with RBS allows the thickness and composition of the film to be determined and ivory distinguished from bone while RBS mapping allows the three-dimensional structure of the film to be determined.

RBS and PIXE analysis of chlorine contamination in ALD-Grown TiN films on silicon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meersschaut, J.; Witters, T.; Kaeyhkoe, M.

2013-04-19

The performance, strengths and limitations of RBS and PIXE for the characterization of trace amounts of Cl in TiN thin films are critically compared. The chlorine atomic concentration in ALD grown TiN thin films on Si is determined for samples grown at temperatures ranging from 350 Degree-Sign C to 550 Degree-Sign C. We show that routine Rutherford backscattering spectrometry measurements (1.5 MeV He{sup +}) and PIXE measurements (1.5 MeV H{sup +}) on 20 nm thick TiN films allow one to determine the Cl content down to 0.3 at% with an absolute statistical accuracy reaching 0.03 at%. Possible improvements to pushmore » the sensitivity limit for both approaches are proposed.« less

Toward VIP-PIX: A Low Noise Readout ASIC for Pixelated CdTe Gamma-Ray Detectors for Use in the Next Generation of PET Scanners.

PubMed

Macias-Montero, Jose-Gabriel; Sarraj, Maher; Chmeissani, Mokhtar; Puigdengoles, Carles; Lorenzo, Gianluca De; Martínez, Ricardo

2013-08-01

VIP-PIX will be a low noise and low power pixel readout electronics with digital output for pixelated Cadmium Telluride (CdTe) detectors. The proposed pixel will be part of a 2D pixel-array detector for various types of nuclear medicine imaging devices such as positron-emission tomography (PET) scanners, Compton gamma cameras, and positron-emission mammography (PEM) scanners. Each pixel will include a SAR ADC that provides the energy deposited with 10-bit resolution. Simultaneously, the self-triggered pixel which will be connected to a global time-to-digital converter (TDC) with 1 ns resolution will provide the event's time stamp. The analog part of the readout chain and the ADC have been fabricated with TSMC 0.25 μ m mixed-signal CMOS technology and characterized with an external test pulse. The power consumption of these parts is 200 μ W from a 2.5 V supply. It offers 4 switchable gains from ±10 mV/fC to ±40 mV/fC and an input charge dynamic range of up to ±70 fC for the minimum gain for both polarities. Based on noise measurements, the expected equivalent noise charge (ENC) is 65 e - RMS at room temperature.

Elemental analysis of aerosol samples collected from an industrial and a non-industrial town of Punjab (India) using PIXE technique.

PubMed

Kumar, Ashok; Sidhu, Pardeep; Nautiyal, Jyoti; Rautray, T R; Sudarshan, M; Kumar, R; Singh, N; Garg, M L; Dhawan, D K

2007-01-01

Chemical composition of the aerosols is an important aspect of aerosol monitoring. The adverse effects on human heath due to different elements in aerosols depend on their concentrations. A comparative study of aerosol concentration and composition from an industrial town Mandi-Gobindgarh and a nearby (25 km away) non-industrial and comparatively less polluted town Morinda, in state Punjab (India) was carried out. Aerosol samples were analyzed by Particle Induced X-ray Emission (PIXE) technique at the Institute of Physics, Bhubaneshwar. Elemental concentrations were found to be much higher in Mandi-Gobindgarh as compared to Morinda. However, the large deviations from the mean concentrations, particularly in Mandi-Gobindgarh is suggestive of highly varying day to day industrial activity and changing weather conditions. Elements such as S, Br and Pb were found higher in the PM2.5 (particulate matter with = 2.5 microm aerodynamic diameter), which are related to burning of coal and oil in furnaces in Mandi-Gobindgarh. The elements related to natural dust such as K, Ca, Ti, Mn, and Fe are mainly distributed in PMcf (particulate matter with aerodynamic diameter between 2.5 and 10 microm) fraction in both the towns. High concentrations of Ti, Cr, Mn, Fe and Zn in the PMcf fraction from Mandi-Gobindgarh are likely due to the industrial activity of Steel rolling mills.

PIXE study of Cuban quaternary paleoclimate geological samples and speleothems.

PubMed

Montero, M E; Aspiazu, J; Pajón, J; Miranda, S; Moreno, E

2000-02-01

PIXE elemental analysis of sediments, speleothems, and other geological formations related to the karst of the Sierra de San Carlos is presented. The similarity of the elemental composition of the sediments studied, as well as the alluvial regime which created them, indicate their common origin at each location. The Sr/Ca concentration ratio of a stalactite indicates that the average atmospheric temperature 12,000 and 18,000 years B.P. was colder than that of 6000 years B.P.

PIXE analysis of trace metals in selenium and copper deficient mice exposed to influenza virus and salicylate

NASA Astrophysics Data System (ADS)

Andres, J. M.; Hurd, R. W.; Van Rinsvelt, H. A.; Small, P. A.; Maenhaut, W.; Vandenhaute, J.

1987-03-01

Reye's syndrome is an acute illness in children manifested by encephalopathy, fatty infiltration of liver, and thymic hypoplasia. The syndrome usually occurs in a susceptible individual with a viral illness who has ingested salicylate. We previously investigated the metal status of children with this syndrome; serum Se and Cu levels were noted to be decreased. Chronic aspirin treatment of rats also produced alterations of serum Se, and liver Se and Cu. We now report our observations for an experimental model of Reye's syndrome. Analysis by PIXE of various metals in Se- and Cu-deficient mice exposed to virus and salicylate are discussed.

Nuclear and atomic analytical techniques in environmental studies in South America.

PubMed

Paschoa, A S

1990-01-01

The use of nuclear analytical techniques for environmental studies in South America is selectively reviewed since the time of earlier works of Lattes with cosmic rays until the recent applications of the PIXE (particle-induced X-ray emission) technique to study air pollution problems in large cities, such as São Paulo and Rio de Janeiro. The studies on natural radioactivity and fallout from nuclear weapons in South America are briefly examined.

IBA techniques: Examples of useful combinations for the characterisation of cultural heritage materials

NASA Astrophysics Data System (ADS)

Beck, L.; Pichon, L.; Moignard, B.; Guillou, T.; Walter, P.

2011-12-01

For many years, ion beam analysis techniques have successfully been used to the study of cultural heritage objects. The chemical composition of work art is usually determined by PIXE, but in many cases, RBS and/or PIGE can provide useful complementary information. RBS gives information about the depth distribution and concentration in light elements, such as carbon and oxygen. In the past years, the experimental facilities at the AGLAE (Accélérateur Grand Louvre d'Analyse Élémentaire) accelerator has been progressively developed in order to apply simultaneously PIXE, PIGE and RBS under optimal conditions using an external beam. This combination is now routinely used for point analyses or mappings. In this contribution, we present several examples of applications: manufacturing technology of lustre-decorated ceramics and silver plating, control of altered or restored surfaces, and quantification of organic phase in painting and bone. The final conclusion is that the association of PIXE with RBS is very attractive for the investigation of cultural heritage objects, in particular of materials containing both mineral and organic components or possessing a multilayered structure. The first results of the production of monochromatic X-rays for radiography purposes by PIXE are also presented.

Standardizing Activation Analysis: New Software for Photon Activation Analysis

NASA Astrophysics Data System (ADS)

Sun, Z. J.; Wells, D.; Segebade, C.; Green, J.

2011-06-01

Photon Activation Analysis (PAA) of environmental, archaeological and industrial samples requires extensive data analysis that is susceptible to error. For the purpose of saving time, manpower and minimizing error, a computer program was designed, built and implemented using SQL, Access 2007 and asp.net technology to automate this process. Based on the peak information of the spectrum and assisted by its PAA library, the program automatically identifies elements in the samples and calculates their concentrations and respective uncertainties. The software also could be operated in browser/server mode, which gives the possibility to use it anywhere the internet is accessible. By switching the nuclide library and the related formula behind, the new software can be easily expanded to neutron activation analysis (NAA), charged particle activation analysis (CPAA) or proton-induced X-ray emission (PIXE). Implementation of this would standardize the analysis of nuclear activation data. Results from this software were compared to standard PAA analysis with excellent agreement. With minimum input from the user, the software has proven to be fast, user-friendly and reliable.

Surface topography of 1€ coin measured by stereo-PIXE

NASA Astrophysics Data System (ADS)

Gholami-Hatam, E.; Lamehi-Rachti, M.; Vavpetič, P.; Grlj, N.; Pelicon, P.

2013-07-01

We demonstrate the stereo-PIXE method by measurement of surface topography of the relief details on 1€ coin. Two X-ray elemental maps were simultaneously recorded by two X-ray detectors positioned at the left and the right side of the proton microbeam. The asymmetry of the yields in the pixels of the two X-ray maps occurs due to different photon attenuation on the exit travel path of the characteristic X-rays from the point of emission through the sample into the X-ray detectors. In order to calibrate the inclination angle with respect to the X-ray asymmetry, a flat inclined surface model was at first applied for the sample in which the matrix composition and the depth elemental concentration profile is known. After that, the yield asymmetry in each image pixel was transferred into corresponding local inclination angle using calculated dependence of the asymmetry on the surface inclination. Finally, the quantitative topography profile was revealed by integrating the local inclination angle over the lateral displacement of the probing beam.

ePix100 camera: Use and applications at LCLS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carini, G. A., E-mail: carini@slac.stanford.edu; Alonso-Mori, R.; Blaj, G.

2016-07-27

The ePix100 x-ray camera is a new system designed and built at SLAC for experiments at the Linac Coherent Light Source (LCLS). The camera is the first member of a family of detectors built around a single hardware and software platform, supporting a variety of front-end chips. With a readout speed of 120 Hz, matching the LCLS repetition rate, a noise lower than 80 e-rms and pixels of 50 µm × 50 µm, this camera offers a viable alternative to fast readout, direct conversion, scientific CCDs in imaging mode. The detector, designed for applications such as X-ray Photon Correlation Spectroscopymore » (XPCS) and wavelength dispersive X-ray Emission Spectroscopy (XES) in the energy range from 2 to 10 keV and above, comprises up to 0.5 Mpixels in a very compact form factor. In this paper, we report the performance of the camera during its first use at LCLS.« less

Combined PIXE and X-ray SEM studies on time-resolved deposits of welding shop aerosols

NASA Astrophysics Data System (ADS)

Barfoot, K. M.; Mitchell, I. V.; Verheyen, F.; Babeliowsky, T.

1981-03-01

Time-resolved deposits of welding shop air particulates have been obtained using a streak sampling system. PIXE analysis of these deposits, using 2 MeV protons, typically revealed the presence of a large number of elements, with many in the range Z = 11-30. Strong variations, up to three orders of magnitude, in the concentrations of several elements such as Al, Si and Fe as well as Zn, Na, K and Ca were found. The 2 h sampling resolution normally used was found to be insufficient to follow the short pollution episodes that regularly occur in a welding shop environment and so sampling with a 20 min resolution was used. The variation of elemental concentrations for different sampling times together with information on the physical nature of these air particulates, determined with a scanning electron microscope (SEM) and Si(Li) X-ray detector attachment, are presented. This type of information together with that obtained from the PIXE analysis is of importance in industrial hygiene studies. The need to make corrections for partial filter clogging, based on air-flow rate monitoring, is discussed.

The use of a single multielement standard for trace analysis in biological materials by external beam PIXE

NASA Astrophysics Data System (ADS)

Biswas, S. K.; Khaliquzzaman, M.; Islam, M. M.; Khan, A. H.

1984-04-01

The validity of the use of a single multielement standard for mass calibration in thick-target external beam PIXE analysis of biological materials has been investigated. In this study, the NBS orchard leaf, SRM 1571, was used as the basic standard for trace element analysis in other biological materials. Using the present procedure, the concentrations of K, Ca, Mn, Fe, Ni, Cu, Zn, Br, Rb and Sr were determined in several NBS reference materials such as bovine liver, spinach, rice flour, etc., generally in 20 μC irradiations with 2.0 MeV protons. The analytical results are compared with certified values of the NBS as well as with other measurements and the sources of errors are discussed.

PIXE investigation of aerosol composition over the Zambian Copperbelt

NASA Astrophysics Data System (ADS)

Meter, S. L.; Formenti, P.; Piketh, S. J.; Annegarn, H. J.; Kneen, M. A.

1999-04-01

Atmospheric sulphate aerosol concentrations are of interest in climate change studies because of their negative climate forcing potential. Quantification of their forcing strength requires the compilation of global sulphur emission inventories to determine the magnitude of regional sources. We report on measurements of the ambient aerosol concentrations in proximity to a copper refinery in the central African Copperbelt, along the border of Zambia and the Democratic Republic of the Congo. This region is historically regarded as one of the largest African sources of sulphate aerosols. Sulphate is produced by oxidation in the atmosphere of SO 2 emitted during the pyrometallurgical processing of Cu-Co sulphide ores. Since the last quantification of sulphur emissions (late 1960s), there has been large-scale reduction in copper production and more frequent use of the leaching technique with negligible sulphur emissions. Samples were collected over four weeks, November-December 1996, at Kitwe, Zambia. A low volume two-stage time-resolving aerosol sampler (streaker) was used. Coarse and fine mode aerosols were separated at >2.5 and >10 μmad. Hourly elemental concentrations were determined by 3.2 MeV PIXE, and routinely yielded Si, S, K, Ca, Ti, Mn, Fe, Cu and Zn, above detection limits. Si, K, Ca and Fe (major crustal components) dominated the coarse elemental mass. In the fine stage, S and Si accounted for up to 80% of the measured mass, and S alone up to 60%. Time series analysis allowed the division of sulphur and crustal elements (Si, K, Ca, Fe) between (i) background concentrations representative of synoptic scale air masses; and (ii) contributions from local sources, i.e., copper smelter and re-suspended soil dust. Short duration episodes of S concentrations, up to 26 μg/m 3, were found simultaneously with enhanced Cu, Fe and Zn. Contributions from individual pyrometallurgic processes and the cobalt slag dump could be distinguished from the elemental signatures. Periods of diminished sulphur concentrations were also identified, indicating a well-mixed regional air mass. These results will contribute towards validating global climate model predictions of aerosol forcing over central Africa.

Trace elements in lake sediments measured by the PIXE technique

NASA Astrophysics Data System (ADS)

Gatti, Luciana V.; Mozeto, Antônio A.; Artaxo, Paulo

1999-04-01

Lakes are ecosystems where there is a great potential of metal accumulation in sediments due to their depositional characteristics. Total concentration of trace elements was measured on a 50 cm long sediment core from the Infernão Lake, that is an oxbow lake of the Moji-Guaçu River basin, in the state of São Paulo, Brazil. Dating of the core shows up to 180 yrs old sediment layers. The use of the PIXE technique for elemental analysis avoids the traditional acid digestion procedure common in other techniques. The multielemental characteristic of PIXE allows a simultaneous determination of about 20 elements in the sediment samples, such as, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Zr, Ba, and Pb. Average values for the elemental composition were found to be similar to the bulk crustal composition. The lake flooding pattern strongly influences the time series of the elemental profiles. Factor analysis of the elemental variability shows five factors. Two of the factors represent the mineralogical matrix, and others represent the organic component, a factor with lead, and another loaded with chromium. The mineralogical component consists of elements such as, Fe, Al, V, Ti, Mn, Ni, K, Zr, Sr, Cu and Zn. The variability of Si is explained by two distinct factors, because it is influenced by two different sources, aluminum-silicates and quartz, and the effect of inundation are different for each other. The organic matter is strongly associated with calcium, and also bounded with S, Zn, Cu and P. Lead and chromium appears as separated factors, although it is not clear the evidences for their anthropogenic origin. The techniques developed for sample preparation and PIXE analysis was proven as advantageous and provided very good reproducibility and accuracy.

Trace element abundance determinations by Synchrotron X Ray Fluorescence (SXRF) on returned comet nucleus mineral grains

NASA Technical Reports Server (NTRS)

Flynn, G. J.; Sutton, S. R.

1989-01-01

Trace element analyses were performed on bulk cosmic dust particles by Proton Induced X Ray Emission (PIXE) and Synchrotron X Ray Fluorescence (SXRF). When present at or near chondritic abundances the trace elements K, Ti, Cr, Mn, Cu, Zn, Ga, Ge, Se, and Br are presently detectable by SXRF in particles of 20 micron diameter. Improvements to the SXRF analysis facility at the National Synchrotron Light Source presently underway should increase the range of detectable elements and permit the analysis of smaller samples. In addition the Advanced Photon Source will be commissioned at Argonne National Laboratory in 1995. This 7 to 8 GeV positron storage ring, specifically designed for high-energy undulator and wiggler insertion devices, will be an ideal source for an x ray microprobe with one micron spatial resolution and better than 100 ppb elemental sensitivity for most elements. Thus trace element analysis of individual micron-sized grains should be possible by the time of the comet nucleus sample return mission.

Naturally occurring levels of elements in fishes as determined by PIXE and XRF methods

NASA Astrophysics Data System (ADS)

Tallandini, L.; Giacobini, F.; Turchetto, M.; Galassini, S.; Liu, Q. X.; Shao, H. R.; Moschini, G.; Moro, R.; Gialanella, G.; Ghermandi, G.; Cecchi, R.; Injuk, J.; Valković, V.

1989-04-01

Naturally occurring levels of S, Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Sb, Sr and Pb were measured in the gills, liver and muscles of fishes ( Zosterisessor ophiocephalus Pall) in the northwestern region of the Adriatic Sea. The overall performance of PIXE and XRF methods was tested by the analysis of standard reference materials. The mean concentration values for elements were calculated from the distribution of experimentally determined concentration values. The obtained data are discussed in the framework of metal metabolism and toxicology.

PIXE analysis of pottery from the recovery of a renaissance wreck

NASA Astrophysics Data System (ADS)

Zucchiatti, A.; Cardoni, F.; Prati, P.; Lucarelli, F.; Mandò, P. A.; Martino, G. P.

1998-03-01

Pottery recovered in a recent marine archaeology campaign in the sea of Liguria (Italy), from the so-called leudo di Varazze wreck, has been analysed by PIXE. By measuring the ratio of each observed element to iron, we have characterised the composition of the clay with particular attention to possible contamination due to the long immersion in the sea. The present results have been associated, in a discriminant analysis, to those obtained during a previous campaign on a set of furnace rejects coming from the towns of Savona and Albissola, to investigate the provenance of the crockery. Both are located a few miles west of the wreck and were important pottery centres.

Report about the Solar Eclipse on August 11, 1999

NASA Astrophysics Data System (ADS)

1999-08-01

This webpage provides information about the total eclipse on Wednesday, August 11, 1999, as it was seen by ESO staff, mostly at or near the ESO Headquarters in Garching (Bavaria, Germany). The zone of totality was about 108 km wide and the ESO HQ were located only 8 km south of the line of maximum totality. The duration of the phase of totality was about 2 min 17 sec. The weather was quite troublesome in this geographical area. Heavy clouds moved across the sky during the entire event, but there were also some holes in between. Consequently, sites that were only a few kilometres from each other had very different viewing conditions. Some photos and spectra of the eclipsed Sun are displayed below, with short texts about the circumstances under which they were made. Please note that reproduction of pictures on this webpage is only permitted, if the author is mentioned as source. Information made available before the eclipse is available here. Eclipse Impressions at the ESO HQ Photo by Eddy Pomaroli Preparing for the Eclipse Photo: Eddy Pomaroli [JEG: 400 x 239 pix - 116k] [JPEG: 800 x 477 pix - 481k] [JPEG: 3000 x 1789 pix - 3.9M] Photo by Eddy Pomaroli During the 1st Partial Phase Photo: Eddy Pomaroli [JPEG: 400 x 275 pix - 135k] [JPEG: 800 x 549 pix - 434k] [JPEG: 2908 x 1997 pix - 5.9M] Photo by Hamid Mehrgan Heavy Clouds Above Digital Photo: Hamid Mehrgan [JPEG: 400 x 320 pix - 140k] [JPEG: 800 x 640 pix - 540k] [JPEG: 1280 x 1024 pix - 631k] Photo by Olaf Iwert Totality Approaching Digital Photo: Olaf Iwert [JPEG: 400 x 320 pix - 149k] [JPEG: 800 x 640 pix - 380k] [JPEG: 1280 x 1024 pix - 536k] Photo by Olaf Iwert Beginning of Totality Digital Photo: Olaf Iwert [JPEG: 400 x 236 pix - 86k] [JPEG: 800 x 471 pix - 184k] [JPEG: 1280 x 753 pix - 217k] Photo by Olaf Iwert A Happy Eclipse Watcher Digital Photo: Olaf Iwert [JPEG: 400 x 311 pix - 144k] [JPEG: 800 x 622 pix - 333k] [JPEG: 1280 x 995 pix - 644k] ESO HQ Eclipse Video Clip [MPEG-version] ESO HQ Eclipse Video Clip (2425 frames/01:37 min) [MPEG Video; 160x120 pix; 2.2M] [MPEG Video; 320x240 pix; 4.4Mb] [RealMedia; streaming; 33kps] [RealMedia; streaming; 200kps] This Video Clip was prepared from a "reportage" of the event at the ESO HQ that was transmitted in real-time to ESO-Chile via ESO's satellite link. It begins with some sequences of the first partial phase and the eclipse watchers. Clouds move over and the landscape darkens as the phase of totality approaches. The Sun is again visible at the very moment this phase ends. Some further sequences from the second partial phase follow. Produced by Herbert Zodet. Dire Forecasts The weather predictions in the days before the eclipse were not good for Munich and surroundings. A heavy front with rain and thick clouds that completely covered the sky moved across Bavaria the day before and the meteorologists predicted a 20% chance of seeing anything at all. On August 10, it seemed that the chances were best in France and in the western parts of Germany, and much less close to the Alps. This changed to the opposite during the night before the eclipse. Now the main concern in Munich was a weather front approaching from the west - would it reach this area before the eclipse? The better chances were then further east, nearer the Austrian border. Many people travelled back and forth along the German highways, many of which quickly became heavily congested. Preparations About 500 persons, mostly ESO staff with their families and friends, were present at the ESO HQ in the morning of August 11. Prior to the eclipse, they received information about the various aspects of solar eclipses and about the specific conditions of this one in the auditorium. Protective glasses were handed out and it was the idea that they would then follow the eclipse from outside. In view of the pessimistic weather forecasts, TV sets had been set up in two large rooms, but in the end most chose to watch the eclipse from the terasse in front of the cafeteria and from the area south of the building. Several telescopes were set up among the trees and on the adjoining field (just harvested). Clouds and Holes It was an unusual solar eclipse experience. Heavy clouds were passing by with sudden rainshowers, but fortunately there were also some holes with blue sky in between. While much of the first partial phase was visible through these, some really heavy clouds moved in a few minutes before the total phase, when the light had begun to fade. They drifted slowly - too slowly! - towards the east and the corona was never seen from the ESO HQ site. From here, the view towards the eclipsed Sun only cleared at the very instant of the second "diamond ring" phenomenon. This was beautiful, however, and evidently took most of the photographers by surprise, so very few, if any, photos were made of this memorable moment. Temperature Curve by Benoit Pirenne Temperature Curve on August 11 [JPEG: 646 x 395 pix - 35k] Measured by Benoit Pirenne - see also his meteorological webpage Nevertheless, the entire experience was fantastic - there were all the expected effects, the darkness, the cool air, the wind and the silence. It was very impressive indeed! And it was certainly a unique day in ESO history! Carolyn Collins Petersen from "Sky & Telescope" participated in the conference at ESO in the days before and watched the eclipse from the "Bürgerplatz" in Garching, about 1.5 km south of the ESO HQ. She managed to see part of the totality phase and filed some dramatic reports at the S&T Eclipse Expedition website. They describe very well the feelings of those in this area! Eclipse Photos Several members of the ESO staff went elsewhere and had more luck with the weather, especially at the moment of totality. Below are some of their impressive pictures. Eclipse Photo by Philippe Duhoux First "Diamond Ring" [JPEG: 400 x 292 pix - 34k] [JPEG: 800 x 583 pix - 144k] [JPEG: 2531 x 1846 pix - 1.3M] Eclipse Photo by Philippe Duhoux Totality [JPEG: 400 x 306 pix - 49k] [JPEG: 800 x 612 pix - 262k] [JPEG: 3039 x 1846 pix - 3.6M] Eclipse Photo by Philippe Duhoux Second "Diamond Ring" [JPEG: 400 x 301 pix - 34k] [JPEG: 800 x 601 pix - 163k] [JPEG: 2905 x 2181 pix - 2.0M] The Corona (Philippe Duhoux) "For the observation of the eclipse, I chose a field on a hill offering a wide view towards the western horizon and located about 10 kilometers north west of Garching." "While the partial phase was mostly cloudy, the sky went clear 3 minutes before the totality and remained so for about 15 minutes. Enough to enjoy the event!" "The images were taken on Agfa CT100 colour slide film with an Olympus OM-20 at the focus of a Maksutov telescope (f = 1000 mm, f/D = 10). The exposure times were automatically set by the camera. During the partial phase, I used an off-axis mask of 40 mm diameter with a mylar filter ND = 3.6, which I removed for the diamond rings and the corona." Note in particular the strong, detached protuberances to the right of the rim, particularly noticeable in the last photo. Eclipse Photo by Cyril Cavadore Totality [JPEG: 400 x 360 pix - 45k] [JPEG: 800 x 719 pix - 144k] [JPEG: 908 x 816 pix - 207k] The Corona (Cyril Cavadore) "We (C.Cavadore from ESO and L. Bernasconi and B. Gaillard from Obs. de la Cote d'Azur) took this photo in France at Vouzier (Champagne-Ardennes), between Reims and Nancy. A large blue opening developed in the sky at 10 o'clock and we decided to set up the telescope and the camera at that time. During the partial phase, a lot of clouds passed over, making it hard to focus properly. Nevertheless, 5 min before totality, a deep blue sky opened above us, allowing us to watch it and to take this picture. 5-10 Minutes after the totality, the sky was almost overcast up to the 4th contact". "The image was taken with a 2x2K (14 µm pixels) Thomson "homemade" CCD camera mounted on a CN212 Takahashi (200 mm diameter telescope) with a 1/10.000 neutral filter. The acquisition software set exposure time (2 sec) and took images in a complete automated way, allowing us to observe the eclipse by naked eye or with binoculars. To get as many images as possible during totality, we use binning 2x2 to reduce the readout time to 19 sec. Afterward, one of the best image was flat-fielded and processed with a special algorithm that modelled a fit the continuous component of the corona and then subtracted from the original image. The remaining details were enhanced by unsharp masking and added to the original image. Finally, gaussian histogram equalization was applied". Eclipse Photo by Eddy Pomaroli Second "Diamond Ring" [JPEG: 400 x 438 pix - 129k] [JPEG: 731 x 800 pix - 277k] [JPEG: 1940 x 2123 pix - 2.3M] Diamond Ring at ESO HQ (Eddy Pomaroli) "Despite the clouds, we saw the second "diamond ring" from the ESO HQ. In a sense, we were quite lucky, since the clouds were very heavy during the total phase and we might easily have missed it all!". "I used an old Minolta SRT-101 camera and a teleobjective (450 mm; f/8). The exposure was 1/125 sec on Kodak Elite 100 (pushed to 200 ASA). I had the feeling that the Sun would become visible and had the camera pointed, by good luck in the correct direction, as soon as the cloud moved away". Eclipse Photo by Roland Reiss First Partial Phase [JPEG: 400 x 330 pix - 94k] [JPEG: 800 x 660 pix - 492k] [JPEG: 3000 x 2475 pix - 4.5M] End of First Partial Phase (Roland Reiss) "I observed the eclipse from my home in Garching. The clouds kept moving and this was the last photo I was able to obtain during the first partial phase, before they blocked everything". "The photo is interesting, because it shows two more images of the eclipsed Sun, below the overexposed central part. In one of them, the remaining, narrow crescent is particularly well visible. They are caused by reflections in the camera. I used a Minolta camera and a Fuji colour slide film". Eclipse Spectra Some ESO people went a step further and obtained spectra of the Sun at the time of the eclipse. Eclipse Spectrum by Roland Reiss Coronal Spectrum [JPEG: 400 x 273 pix - 94k] [JPEG: 800 x 546 pix - 492k] [JPEG: 3000 x 2046 pix - 4.5M] Coronal Spectrum (CAOS Group) The Club of Amateurs in Optical Spectroscopy (with Carlos Guirao Sanchez, Gerardo Avila and Jesus Rodriguez) obtained a spectrum of the solar corona from a site in Garching, about 2 km south of the ESO HQ. "This is a plot of the spectrum and the corresponding CCD image that we took during the total eclipse. The main coronal lines are well visible and have been identified in the figure. Note in particular one at 6374 Angstrom that was first ascribed to the mysterious substance "Coronium". We now know that it is emitted by iron atoms that have lost nine electrons (Fe X)". The equipment was: * Telescope: Schmidt Cassegrain F/6.3; Diameter: 250 mm * FIASCO Spectrograph: Fibre: 135 micron core diameter F = 100 mm collimator, f = 80 mm camera; Grating: 1300 gr/mm blazed at 500 nm; SBIG ST8E CCD camera; Exposure time was 20 sec. Eclipse Spectrum by Bob Fosbury Chromospheric Spectrum [JPEG: 120 x 549 pix - 20k] Chromospheric and Coronal Spectra (Bob Fosbury) "The 11 August 1999 total solar eclipse was seen from a small farm complex called Wolfersberg in open fields some 20km ESE of the centre of Munich. It was chosen to be within the 2min band of totality but likely to be relatively unpopulated". "There were intermittent views of the Sun between first and second contact with quite a heavy rainshower which stopped 9min before totality. A large clear patch of sky revealed a perfect view of the Sun just 2min before second contact and it remained clear for at least half an hour after third contact". "The principal project was to photograph the spectrum of the chromosphere during totality using a transmission grating in front of a moderate telephoto lens. The desire to do this was stimulated by a view of the 1976 eclipse in Australia when I held the same grating up to the eclipsed Sun and was thrilled by the view of the emission line spectrum. The trick now was to get the exposure right!". "A sequence of 13 H-alpha images was combined into a looping movie. The exposure times were different, but some attempt has been made to equalise the intensities. The last two frames show the low chromosphere and then the photosphere emerging at 3rd contact. The [FeX] coronal line can be seen on the left in the middle of the sequence. I used a Hasselblad camera and Agfa slide film (RSX II 100)".

GIT1/βPIX signaling proteins and PAK1 kinase regulate microtubule nucleation.

PubMed

Černohorská, Markéta; Sulimenko, Vadym; Hájková, Zuzana; Sulimenko, Tetyana; Sládková, Vladimíra; Vinopal, Stanislav; Dráberová, Eduarda; Dráber, Pavel

2016-06-01

Microtubule nucleation from γ-tubulin complexes, located at the centrosome, is an essential step in the formation of the microtubule cytoskeleton. However, the signaling mechanisms that regulate microtubule nucleation in interphase cells are largely unknown. In this study, we report that γ-tubulin is in complexes containing G protein-coupled receptor kinase-interacting protein 1 (GIT1), p21-activated kinase interacting exchange factor (βPIX), and p21 protein (Cdc42/Rac)-activated kinase 1 (PAK1) in various cell lines. Immunofluorescence microscopy revealed association of GIT1, βPIX and activated PAK1 with centrosomes. Microtubule regrowth experiments showed that depletion of βPIX stimulated microtubule nucleation, while depletion of GIT1 or PAK1 resulted in decreased nucleation in the interphase cells. These data were confirmed for GIT1 and βPIX by phenotypic rescue experiments, and counting of new microtubules emanating from centrosomes during the microtubule regrowth. The importance of PAK1 for microtubule nucleation was corroborated by the inhibition of its kinase activity with IPA-3 inhibitor. GIT1 with PAK1 thus represent positive regulators, and βPIX is a negative regulator of microtubule nucleation from the interphase centrosomes. The regulatory roles of GIT1, βPIX and PAK1 in microtubule nucleation correlated with recruitment of γ-tubulin to the centrosome. Furthermore, in vitro kinase assays showed that GIT1 and βPIX, but not γ-tubulin, serve as substrates for PAK1. Finally, direct interaction of γ-tubulin with the C-terminal domain of βPIX and the N-terminal domain of GIT1, which targets this protein to the centrosome, was determined by pull-down experiments. We propose that GIT1/βPIX signaling proteins with PAK1 kinase represent a novel regulatory mechanism of microtubule nucleation in interphase cells. Copyright © 2016 Elsevier B.V. All rights reserved.

Piroxicam/2-hydroxypropyl-beta-cyclodextrin inclusion complex prepared by a new fluid-bed coating technique.

PubMed

Zhang, Xingwang; Wu, Danni; Lai, Jie; Lu, Yi; Yin, Zongning; Wu, Wei

2009-02-01

This work was aimed at investigating the feasibility of fluid-bed coating as a new method to prepare cyclodextrin inclusion complex. The inclusion complex of the model drug piroxicam (PIX) and 2-hydroxypropyl-beta-cyclodextrin (HPCD) in aqueous ethanol solution was sprayed and deposited onto the surface of the pellet substrate upon removal of the solvent. The coating process was fluent with high coating efficiency. Scanning electron microscopy revealed a coarse pellet surface, and a loosely packed coating structure. Significantly enhanced dissolution, over 90% at 5 min, was observed at stoichiometric PIX/HPCD molar ratio (1/1) and at a ratio with excessive HPCD (1/2). Differential scanning calorimetry and powder X-ray diffractometry confirmed absence of crystallinity of PIX at PIX/HPCD molar ratio of 1/1 and 1/2. Fourier transform-infrared spectrometry and Raman spectrometry revealed interaction between PIX and HPCD adding evidence on inclusion of PIX moieties into HPCD cavities. Solid-state (13)C NMR spectrometry indicated possible inclusion of PIX through the pyridine ring. It is concluded that fluid-bed coating has potential to be used as a new technique to prepare cyclodextrin inclusion complex.

Expanding the versatility of phage display II: improved affinity selection of folded domains on protein VII and IX of the filamentous phage.

PubMed

Løset, Geir Åge; Roos, Norbert; Bogen, Bjarne; Sandlie, Inger

2011-02-24

Phage display is a leading technology for selection of binders with affinity for specific target molecules. Polypeptides are normally displayed as fusions to the major coat protein VIII (pVIII) or the minor coat protein III (pIII). Whereas pVIII display suffers from drawbacks such as heterogeneity in display levels and polypeptide fusion size limitations, toxicity and infection interference effects have been described for pIII display. Thus, display on other coat proteins such as pVII or pIX might be more attractive. Neither pVII nor pIX display have gained widespread use or been characterized in detail like pIII and pVIII display. Here we present a side-by-side comparison of display on pIII with display on pVII and pIX. Polypeptides of interest (POIs) are fused to pVII or pIX. The N-terminal periplasmic signal sequence, which is required for phage integration of pIII and pVIII and that has been added to pVII and pIX in earlier studies, is omitted altogether. Although the POI display level on pIII is higher than on pVII and pIX, affinity selection with pVII and pIX display libraries is shown to be particularly efficient. Display through pVII and/or pIX represent platforms with characteristics that differ from those of the pIII platform. We have explored this to increase the performance and expand the use of phage display. In the paper, we describe effective affinity selection of folded domains displayed on pVII or pIX. This makes both platforms more attractive alternatives to conventional pIII and pVIII display than they were before.

Quantitative measurement of essential and not essential metals in muscular, hepatic and renal tissue of horses by means of PIXE technique

NASA Astrophysics Data System (ADS)

Balzan, S.; Buoso, M. C.; Ceccato, D.; De Poli, M.; Giaccone, V.; Moschini, G.; Novelli, E.; Olabanji, S. O.; Passi, P.; Tepedino, V.

2004-06-01

Nowadays, the food safety and the related health risks for humans are a major issue. It has become a priority to ensure the health and well-being of the population through the better scientific understanding of the food intake influence. A frequently found harmful feature of human diet is the simultaneous presence in food stuff of both essential and toxic elements. A significant example of this situation is represented by horse meat. The aim of this survey is to evaluate the elemental content of muscular, hepatic and renal tissues of horses bred in different countries of the East of Europe and slaughtered in Italy. The studied population consisted of about 100 individuals; the sampling period, coinciding with the highest market request, was extended from November to March. Freeze dried tissues were pelletized and carbon coated prior to analysis. The samples were analyzed using Particle Induced X-ray Emission (PIXE) technique at the AN2000 van de Graaff accelerator of the INFN-National Laboratories of Legnaro. The accuracy of the results was verified using certified standard reference materials prepared and measured in the same experimental conditions. Results have highlighted the noble nutritional values of horse muscular tissue in terms of iron, zinc and calcium content. Cadmium was staidly identified in horse kidneys, with an average concentration of 257 μg/g on dried matter, while in liver it was sporadically present.

Dependence of precipitation of trace elements on pH in standard water

NASA Astrophysics Data System (ADS)

Verma, Shivcharan; Mohanty, Biraja P.; Singh, K. P.; Behera, B. R.; Kumar, Ashok

2018-04-01

The present work aimed to study the dependence of precipitation of trace elements on the pH of solution. A standard solution was prepared by using ultrapure deionized water (18.2 MΩ/cm) as the solvent and 11 water-soluble salts having different elements as solutes. Five samples of different pH values (2 acidic, 2 basic, and 1 neutral) were prepared from this standard solution. Sodium-diethyldithiocarbamate was used as the chelating agent to precipitate the metal ions present in these samples of different pH values. The targets were prepared by collecting these precipitates on mixed cellulose esters filter of 0.4 μm pore size by vacuum filtration. Elemental analysis of these targets was performed by particle-induced X-ray emission (PIXE) using 2.7 MeV protons from the single Dee variable energy cyclotron at Panjab University, Chandigarh, India. PIXE data were analyzed using GUPIXWIN software. For most of the elements, except Hg with oxidation state +2, such as Co, Ni, Zn, Ba, and Cd, a general trend of enhancement in precipitation was observed with the increase in pH. However, for other elements such as V, As, Mo, Ag, and Bi, which have oxidation state other than +2, no definite pattern was observed. Precipitation of Ba and As using this method was negligible at all five pH values. From these results, it can be concluded that the precipitation and recovery of elements depend strongly on the pH of the water sample.

PIGE-PIXE analysis of chewing sticks of pharmacological importance

NASA Astrophysics Data System (ADS)

Olabanji, S. O.; Makanju, O. V.; Haque, A. M. I.; Buoso, M. C.; Ceccato, D.; Cherubini, R.; Moschini, G.

1996-06-01

PIGE and PIXE techniques were employed for the determination of the major, minor and trace elemental concentrations in chewing sticks of pharmacological importance namely: Butyrospermum paradoxum, Garcinia kola, Distemonanthus benthamianus, Bridelia ferruginea, Anogeissus leiocarpus, Terminalia glaucescens and Fagara rubescens, respectively. The concentration of fluorine which is very important for human dental enamel was specially determined using the 19F(p, p'γ) 19F reaction. For decades these chewing sticks when used alone without toothpastes have proven to be very efficient, effective and reliable in cleaning the teeth of many people particularly in Nigeria and some other countries in Africa. The teeth of users are usually very strong, clean, fresh and devoid of germs and caries. Even with the advent of modern toothpastes with special additions of fluorine, the use of these popular and efficient chewing sticks is still unabated. Many people including the elite use them solely, a few others combine their use with modern toothpastes and brush. Proton beams produced by the 7 MV CN and 2.5 MV AN 2000 Van de Graaff accelerators at INFN, Laboratori Nazionali di Legnaro (LNL), Padova, Italy were used for the PIGE and PIXE analysis, respectively. Results of this novel study are presented and discussed.

Elucidating the Wavelength Dependence of Phonon Scattering in Nanoparticle-Matrix Composites using Phonon Spectroscopy

DTIC Science & Technology

2016-07-11

composites with x - ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Rutherford backscattering spectroscopy...RBS), particle-induced x - ray emission (PIXE), and energy dispersive x - ray spectroscopy (EDX). This work complements earlier works on CdSe...sample shows only In2Se3 and CdIn2Se4 XRD peaks (Figure 1.4e), it is stoichiometrically   Figure 1.4. X - ray diffraction patterns of (a) γ-In2Se3

Status of ion sources at National Institute of Radiological Sciences.

PubMed

Kitagawa, A; Fujita, T; Goto, A; Hattori, T; Hamano, T; Hojo, S; Honma, T; Imaseki, H; Katagiri, K; Muramatsu, M; Sakamoto, Y; Sekiguchi, M; Suda, M; Sugiura, A; Suya, N

2012-02-01

The National Institute of Radiological Sciences (NIRS) maintains various ion accelerators in order to study the effects of radiation of the human body and medical uses of radiation. Two electrostatic tandem accelerators and three cyclotrons delivered by commercial companies have offered various life science tools; these include proton-induced x-ray emission analysis (PIXE), micro beam irradiation, neutron exposure, and radioisotope tracers and probes. A duoplasmatron, a multicusp ion source, a penning ion source (PIG), and an electron cyclotron resonance ion source (ECRIS) are in operation for these purposes. The Heavy-Ion Medical Accelerator in Chiba (HIMAC) is an accelerator complex for heavy-ion radiotherapy, fully developed by NIRS. HIMAC is utilized not only for daily treatment with the carbon beam but also for fundamental experiments. Several ECRISs and a PIG at HIMAC satisfy various research and clinical requirements.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kitagawa, A.; Fujita, T.; Goto, A.

The National Institute of Radiological Sciences (NIRS) maintains various ion accelerators in order to study the effects of radiation of the human body and medical uses of radiation. Two electrostatic tandem accelerators and three cyclotrons delivered by commercial companies have offered various life science tools; these include proton-induced x-ray emission analysis (PIXE), micro beam irradiation, neutron exposure, and radioisotope tracers and probes. A duoplasmatron, a multicusp ion source, a penning ion source (PIG), and an electron cyclotron resonance ion source (ECRIS) are in operation for these purposes. The Heavy-Ion Medical Accelerator in Chiba (HIMAC) is an accelerator complex for heavy-ionmore » radiotherapy, fully developed by NIRS. HIMAC is utilized not only for daily treatment with the carbon beam but also for fundamental experiments. Several ECRISs and a PIG at HIMAC satisfy various research and clinical requirements.« less

Status of ion sources at National Institute of Radiological Sciencesa)

NASA Astrophysics Data System (ADS)

Kitagawa, A.; Fujita, T.; Goto, A.; Hattori, T.; Hamano, T.; Hojo, S.; Honma, T.; Imaseki, H.; Katagiri, K.; Muramatsu, M.; Sakamoto, Y.; Sekiguchi, M.; Suda, M.; Sugiura, A.; Suya, N.

2012-02-01

The National Institute of Radiological Sciences (NIRS) maintains various ion accelerators in order to study the effects of radiation of the human body and medical uses of radiation. Two electrostatic tandem accelerators and three cyclotrons delivered by commercial companies have offered various life science tools; these include proton-induced x-ray emission analysis (PIXE), micro beam irradiation, neutron exposure, and radioisotope tracers and probes. A duoplasmatron, a multicusp ion source, a penning ion source (PIG), and an electron cyclotron resonance ion source (ECRIS) are in operation for these purposes. The Heavy-Ion Medical Accelerator in Chiba (HIMAC) is an accelerator complex for heavy-ion radiotherapy, fully developed by NIRS. HIMAC is utilized not only for daily treatment with the carbon beam but also for fundamental experiments. Several ECRISs and a PIG at HIMAC satisfy various research and clinical requirements.

Topographic PIXE analysis of platinum levels in kidney slices from CIS-platin treated patients

NASA Astrophysics Data System (ADS)

Dikhoff, T. G. M. H.; Van Der Heide, J. A.; McVie, J. G.

1985-05-01

Concentrations of platinum and several other trace elements have been measured exploiting a 50 × 50 μ proton beam for PIXE analysis. The thickness of a selective germanium absorber for the spectral resolution of platinum L β and selenium K α peaks optimized, taking into account the fluorescent X-rays excited in the absorber material. The measurements have been performed in the framework of a project on the assessment of the toxicity of cytostatic platinum compounds. The lateral distributions of platinum in human kidneys and in dog tissues were measured. The highest concentrations of platinum were seen in arterial walls, followed by glomeruli and tubules. Chronic kidney damage may be correlated to this pattern of retention.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, R.F.; Kravchenko, I.I.; Kuharik, J.C.

Widespread use of chromated copper arsenate (CCA) as a wood preservative has led to increasing public concern regarding possible toxic contamination of areas surrounding CCA-treated structures, e.g., decks, playground equipment, etc. Appreciable leaching of arsenic, chromium, and copper into soils adjacent to such structures has been demonstrated via standard techniques of analytical chemistry. The advantages of PIXE [rapid analysis, quick sample turnover, possible lower cost] suggest its application to this area of interest. PIXE studies in our laboratory of CCA-contaminated soil samples show good agreement with previous analyses of As, Cu, Cr, and other heavy-elemental content, with some variability inmore » diffusion rates.« less

Characterization of Byzantine pottery from Oltina (Constanţa County), Romania, using PIXE and Optical Microscopy

NASA Astrophysics Data System (ADS)

Bugoi, Roxana; Talmaţchi, Cristina; Haitǎ, Constantin; Ceccato, Daniele

2018-02-01

An assemblage of 58 ceramic shards discovered in archaeological excavations at Oltina, Romania, dated to the 10th-11th century CE, was subjected to archaeometric investigations in order to reveal the raw materials and manufacturing techniques employed by the potters from the Lower Danube zone during the Byzantine ruling. The initial grouping of the shards according to stylistic criteria was refined by the subsequent petrographic study. Optical Microscopy (OM) detailed the general mineralogy and the pottery fabric, i.e. the textural characteristics, porosity and microstructure, surface treatments and firing. The PIXE analyses of potteries performed at AN2000 accelerator of LNL, INFN, Italy led to the identification of the chemical composition of the ceramic shards. The Hierarchical Cluster Analysis of the PIXE data evidenced several categories of shards with distinct compositional signatures, the main division being the one separating the ceramic fragments made of kaolinitic clays from the rest of the Oltina potteries.

Scanning-PIXE analysis of gold lace embroideries in a relic of St. Francis

NASA Astrophysics Data System (ADS)

Migliori, A.; Grassi, N.; Mandò, P. A.

2008-05-01

In this work, we describe the compositional analysis performed by scanning-mode PIXE on the metal threads of a XIII century embroidery. The precious work analysed is the pillow-case used to cover the pillow, on which - according to tradition - St. Francis of Assisi was resting his head when he died. Measurements were performed in order to characterise the embroideries of the two sides and the passementerie in the lateral hems. Several areas, each of the order of two square millimetres, were scanned with a 3 MeV proton external beam of 20 μm size on target, using the external micro-beam facility of our laboratory, with list-mode acquisition. Analysis of elemental maps and spectra from selected homogeneous sub-areas allowed us to extract the quantitative composition of the gilded tape and estimates of its thickness.

Development Of PIXE Measurement Of Ca Changes Resulting From Viral Transduction In Cells

NASA Astrophysics Data System (ADS)

Whitlow, Harry J.; Chienthavorn, Orapin; Eronen, Hannele; Sajavaara, Timo; Laitinen, Mikko; Norarat, Rattanaporn; Gilbert, Leona K.

2011-06-01

Ca is a life-element of particular interest because it is both bound to proteins, and as Ca2+ which functions as a signal molecule in apoptosis. Here we report development of chemical-matrix blind assaying the Ca fluxes from transduced HepG2 cells using particle induced X-ray emission. The cells were transduced with recombinant baculoviruses hosting the DNA for non-structural protein 1 (NS1) of the human pavovirus B19. Different recombinant baculoviruses were used that carried different DNA payloads of this NS1. Two different approaches have been developed to assay Ca in cells. The first is where the cells were directly cultured using a self-supporting pioloform as a substrate. In the second approach the cells are permeabilized, and bound-Ca content in the debris, and unbound-Ca in the wash solutions were measured using an internal V reference standard. The results support a difference in the Ca contents depending on the payload of the infecting virus, however the PIXE signals were too close to the minimum detection limit to draw reliable conclusions.

Quantitative investigation of physical factors contributing to gold nanoparticle-mediated proton dose enhancement.

PubMed

Cho, Jongmin; Gonzalez-Lepera, Carlos; Manohar, Nivedh; Kerr, Matthew; Krishnan, Sunil; Cho, Sang Hyun

2016-03-21

Some investigators have shown tumor cell killing enhancement in vitro and tumor regression in mice associated with the loading of gold nanoparticles (GNPs) before proton treatments. Several Monte Carlo (MC) investigations have also demonstrated GNP-mediated proton dose enhancement. However, further studies need to be done to quantify the individual physical factors that contribute to the dose enhancement or cell-kill enhancement (or radiosensitization). Thus, the current study investigated the contributions of particle-induced x-ray emission (PIXE), particle-induced gamma-ray emission (PIGE), Auger and secondary electrons, and activation products towards the total dose enhancement. Specifically, GNP-mediated dose enhancement was measured using strips of radiochromic film that were inserted into vials of cylindrical GNPs, i.e. gold nanorods (GNRs), dispersed in a saline solution (0.3 mg of GNRs/g or 0.03% of GNRs by weight), as well as vials containing water only, before proton irradiation. MC simulations were also performed with the tool for particle simulation code using the film measurement setup. Additionally, a high-purity germanium detector system was used to measure the photon spectrum originating from activation products created from the interaction of protons and spherical GNPs present in a saline solution (20 mg of GNPs/g or 2% of GNPs by weight). The dose enhancement due to PIXE/PIGE recorded on the films in the GNR-loaded saline solution was less than the experimental uncertainty of the film dosimetry (<2%). MC simulations showed highly localized dose enhancement (up to a factor 17) in the immediate vicinity (<100 nm) of GNRs, compared with hypothetical water nanorods (WNRs), mostly due to GNR-originated Auger/secondary electrons; however, the average dose enhancement over the entire GNR-loaded vial was found to be minimal (0.1%). The dose enhancement due to the activation products from GNPs was minimal (<0.1%) as well. In conclusion, under the currently investigated conditions that are considered clinically relevant, PIXE, PIGE, and activation products contribute minimally to GNP/GNR-mediated proton dose enhancement, whereas Auger/secondary electrons contribute significantly but only at short distances (<100 nm) from GNPs/GNRs.

Expanding the Versatility of Phage Display II: Improved Affinity Selection of Folded Domains on Protein VII and IX of the Filamentous Phage

PubMed Central

Løset, Geir Åge; Roos, Norbert; Bogen, Bjarne; Sandlie, Inger

2011-01-01

Background Phage display is a leading technology for selection of binders with affinity for specific target molecules. Polypeptides are normally displayed as fusions to the major coat protein VIII (pVIII) or the minor coat protein III (pIII). Whereas pVIII display suffers from drawbacks such as heterogeneity in display levels and polypeptide fusion size limitations, toxicity and infection interference effects have been described for pIII display. Thus, display on other coat proteins such as pVII or pIX might be more attractive. Neither pVII nor pIX display have gained widespread use or been characterized in detail like pIII and pVIII display. Methodology/Principal Findings Here we present a side-by-side comparison of display on pIII with display on pVII and pIX. Polypeptides of interest (POIs) are fused to pVII or pIX. The N-terminal periplasmic signal sequence, which is required for phage integration of pIII and pVIII and that has been added to pVII and pIX in earlier studies, is omitted altogether. Although the POI display level on pIII is higher than on pVII and pIX, affinity selection with pVII and pIX display libraries is shown to be particularly efficient. Conclusions/Significance Display through pVII and/or pIX represent platforms with characteristics that differ from those of the pIII platform. We have explored this to increase the performance and expand the use of phage display. In the paper, we describe effective affinity selection of folded domains displayed on pVII or pIX. This makes both platforms more attractive alternatives to conventional pIII and pVIII display than they were before. PMID:21390283

The GIT–PIX complexes regulate the chemotactic response of rat basophilic leukaemia cells

PubMed Central

Gavina, Manuela; Za, Lorena; Molteni, Raffaella; Pardi, Ruggero; Curtis, Ivan de

2009-01-01

Background information. Cell motility entails the reorganization of the cytoskeleton and membrane trafficking for effective protrusion. The GIT–PIX protein complexes are involved in the regulation of cell motility and adhesion and in the endocytic traffic of members of the family of G-protein-coupled receptors. We have investigated the function of the endogenous GIT complexes in the regulation of cell motility stimulated by fMLP (formyl-Met-Leu-Phe) peptide, in a rat basophilic leukaemia RBL-2H3 cell line stably expressing an HA (haemagglutinin)-tagged receptor for the fMLP peptide. Results. Our analysis shows that RBL cells stably transfected with the chemoattractant receptor expressed both GIT1–PIX and GIT2–PIX endogenous complexes. We have used silencing of the different members of the complex by small interfering RNAs to study the effects on a number of events linked to agonist-induced cell migration. We found that cell adhesion was not affected by depletion of any of the proteins of the GIT complex, whereas agonist-enhanced cell spreading was inhibited. Analysis of agonist-stimulated haptotactic cell migration indicated a specific positive effect of GIT1 depletion on trans-well migration. The internalization of the formyl-peptide receptor was also inhibited by depletion of GIT1 and GIT2. The effects of the GIT complexes on trafficking of the receptors was confirmed by an antibody-enhanced agonist-induced internalization assay, showing that depletion of PIX, GIT1 or GIT2 protein caused decreased perinuclear accumulation of internalized receptors. Conclusions. Our results show that endogenous GIT complexes are involved in the regulation of chemoattractant-induced cell motility and receptor trafficking, and support previous findings indicating an important function of the GIT complexes in the regulation of different G-protein-coupled receptors. Our results also indicate that endogenous GIT1 and GIT2 regulate distinct subsets of agonist-induced responses and suggest a possible functional link between the control of receptor trafficking and the regulation of cell motility by GIT proteins. PMID:19912111

Successful "First Light" for VLT High-Resolution Spectrograph

NASA Astrophysics Data System (ADS)

1999-10-01

Great Research Prospects with UVES at KUEYEN A major new astronomical instrument for the ESO Very Large Telescope at Paranal (Chile), the UVES high-resolution spectrograph, has just made its first observations of astronomical objects. The astronomers are delighted with the quality of the spectra obtained at this moment of "First Light". Although much fine-tuning still has to be done, this early success promises well for new and exciting science projects with this large European research facility. Astronomical instruments at VLT KUEYEN The second VLT 8.2-m Unit Telescope, KUEYEN ("The Moon" in the Mapuche language), is in the process of being tuned to perfection before it will be "handed" over to the astronomers on April 1, 2000. The testing of the new giant telescope has been successfully completed. The latest pointing tests were very positive and, from real performance measurements covering the entire operating range of the telescope, the overall accuracy on the sky was found to be 0.85 arcsec (the RMS-value). This is an excellent result for any telescope and implies that KUEYEN (as is already the case for ANTU) will be able to acquire its future target objects securely and efficiently, thus saving precious observing time. This work has paved the way for the installation of large astronomical instruments at its three focal positions, all prototype facilities that are capable of catching the light from even very faint and distant celestial objects. The three instruments at KUEYEN are referred to by their acronyms UVES , FORS2 and FLAMES. They are all dedicated to the investigation of the spectroscopic properties of faint stars and galaxies in the Universe. The UVES instrument The first to be installed is the Ultraviolet Visual Echelle Spectrograph (UVES) that was built by ESO, with the collaboration of the Trieste Observatory (Italy) for the control software. Complete tests of its optical and mechanical components, as well as of its CCD detectors and of the complex control system, cf. ESO PR Photos 44/98 , were made in the laboratories of the ESO Headquarters in Garching (Germany) before it was fully dismounted and shipped (some parts by air, others by ship) to the ESO Paranal Observatory, 130 km south of Antofagasta (Chile). Here, the different pieces of UVES (with a total weight of 8 tons) were carefully reassembled on the Nasmyth platform of KUEYEN and made ready for real observations (see ESO PR Photos 36p-t/99 ). UVES is a complex two-channel spectrograph that has been built around two giant optical (echelle diffraction) gratings, each ruled on a 84 cm x 21 cm x 12 cm block of the ceramic material Zerodur (the same that is used for the VLT 8.2-m main mirrors) and weighing more than 60 kg. These echelle gratings finely disperse the light from celestial objects collected by the telescope into its constituent wavelengths (colours). UVES' resolving power (an optical term that indicates the ratio between a given wavelength and the smallest wavelength difference between two spectral lines that are clearly separated by the spectrograph) may reach 110,000, a very high value for an astronomical instrument of such a large size. This means for instance that even comparatively small changes in radial velocity (a few km/sec only) can be accurately measured and also that it is possible to detect the faint spectral signatures of very rare elements in celestial objects. One UVES channel is optimized for the ultraviolet and blue, the other for visual and red light. The spectra are digitally recorded by two highly efficient CCD detectors for subsequent analysis and astrophysical interpretation. By optimizing the transmission of the various optical components in its two channels, UVES has a very high efficiency all the way from the UV (wavelength about 300 nm) to the near-infrared (1000 nm or 1 µm). This guarantees that only a minimum of the precious light that is collected by KUEYEN is lost and that detailed spectra can be obtained of even quite faint objects, down to about magnitude 20 (corresponding to nearly one million times fainter than what can be perceived with the unaided eye). The possibility of doing simultaneous observations in the two channels (with a dichroic mirror) ensures a further gain in data gathering efficiency. First Observations with UVES In the evening of September 27, 1999, the ESO astronomers turned the KUEYEN telescope and - for the first time - focussed the light of stars and galaxies on the entrance aperture of the UVES instrument. This is the crucial moment of "First Light" for a new astronomical facility. The following test period will last about three weeks. Much of the time during the first observing nights was spent by functional tests of the various observation modes and by targeting "standard stars" with well-known properties in order to measure the performance of the new instrument. They showed that it is behaving very well. This marks the beginning of a period of progressive fine-tuning that will ultimately bring UVES to peak performance. The astronomers also did a few "scientific" observations during these nights, aimed at exploring the capabilities of their new spectrograph. They were eager to do so, also because UVES is the first spectrograph of this type installed at a telescope of large diameter in the southern hemisphere . Many exciting research possibilities are now opening with UVES . They include a study of the chemical history of many galaxies in the Local Group, e.g. by observing the most metal-poor (oldest) stars in the Milky Way Galaxy and by obtaining the first, extremely detailed spectra of their brightest stars in the Magellanic Clouds. Quasars and distant compact galaxies will also be among the most favoured targets of the first UVES observers, not least because their spectra carry crucial information about the density, physical state and chemical composition of the early Universe. UVES First Light: SN 1987A One of the first spectral test exposures with UVES at KUEYEN was of SN 1987A , the famous supernova that exploded in the Large Magellanic Cloud (LMC) in February 1987, and the brightest supernova of the last 400 years. ESO PR Photo 37a/99 ESO PR Photo 37a/99 [Preview - JPEG: 400 x 455 pix - 87k] [Normal - JPEG: 645 x 733 pix - 166k] Caption to ESO PR Photo 37a/99 : This is a direct image of SN1987A, flanked by two nearby stars. The distance between these two is 4.5 arcsec. The slit (2.0 arcsec wide) through which the echelle spectrum shown in PR Photo 37b/99 was obtained, is outlined. This reproduction is from a 2-min exposure through a R(ed) filter with the FORS1 multi-mode instrument at VLT ANTU, obtained in 0.55 arcsec seeing on September 20, 1998. North is up and East is left. ESO PR Photo 37b/99 ESO PR Photo 37b/99 [Preview - JPEG: 400 x 459 pix - 130k] [Normal - JPEG: 800 x 917 pix - 470k] [High-Res - JPEG: 3000 x 3439 pix - 6.5M] Caption to ESO PR Photo 37b/99 : This shows the raw image, as read from the CCD, with the recorded echelle spectrum of SN1987A. With this technique, the supernova spectrum is divided into many individual parts ( spectral orders , each of which appears as a narrow horizontal line) that together cover the wavelength interval from 479 to 682 nm (from the bottom to the top), i.e. from blue to red light. Many bright emission lines from different elements are visible, e.g. the strong H-alpha line from hydrogen near the centre of the fourth order from the top. Emission lines from the terrestrial atmosphere are seen as vertical bright lines that cover the full width of the individual horizontal bands. Since this exposure was done with the nearly Full Moon above the horizon, an underlying, faint absorption-line spectrum of reflected sunlight is also visible. The exposure time was 30 min and the seeing conditions were excellent (0.5 arcsec). ESO PR Photo 37c/99 ESO PR Photo 37c/99 [Preview - JPEG: 400 x 355 pix - 156k] [Normal - JPEG: 800 x 709 pix - 498k] [High-Res - JPEG: 1074 x 952 pix - 766k] Caption to ESO PR Photo 37c/99 : This false-colour image has been extracted from another UVES echelle spectrum of SN 1987A, similar to the one shown in PR Photo 37b/99 , but with a slit width of 1 arcsec only. The upper part shows the emission lines of nitrogen, sulfur and hydrogen, as recorded in some of the spectral orders. The pixel coordinates (X,Y) in the original frame are indicated; the red colour indicates the highest intensities. Below is a more detailed view of the complex H-alpha emission line, with the corresponding velocities and the position along the spectrograph slit indicated. Several components of this line can be distinguished. The bulk of the emission (here shown in red colour) comes from the ring surrounding the supernova; the elongated shape here is due to the differential velocity exhibited by the near (to us) and far sides of the ring. The two bright spots on either side are emission from two outer rings (not immediately visible in PR Photo 37a/99 ). The extended emission in the velocity direction originates from material inside the ring upon which the fastest moving ejecta from the supernova have impacted (As seen in VLT data obtained previously with the ANTU/ISAAC combination (cf. PR Photo 11/99 ), exciting times now lie ahead for SN 1987A. The ejecta moving at 30,000 km/s (1/10th the speed of light) have now, 12 years after the explosion, reached the ring of material and the predicted "fireworks" are about to be ignited.) Finally, there is a broad emission extending all along the spectrograph slit (here mostly yellow) upon which the ring emission is superimposed. This is not associated with the supernova itself, but is H-alpha emission by diffuse gas in the Large Magellanic Cloud (LMC) in which SN 1987A is located. UVES First Light: QSO HE2217-2818 The power of UVES is demonstrated by this two-hour test exposure of the southern quasar QSO HE2217-2818 with U-magnitude = 16.5 and a redshift of z = 2.4. It was discovered a few years ago during the Hamburg-ESO Quasar Survey , by means of photographic plates taken with the 1-m ESO Schmidt Telescope at La Silla, the other ESO astronomical site in Chile. ESO PR Photo 37d/99 ESO PR Photo 37d/99 [Preview - JPEG: 400 x 309 pix - 92k] [Normal - JPEG: 800x 618 pix - 311k] [High-Res - JPEG: 3000 x 2316 pix - 5.0M] ESO PR Photo 37e/99 ESO PR Photo 37e/99 [Preview - JPEG: 400 x 310 pix - 43k] [Normal - JPEG: 800 x 619 pix - 100k] [High-Res - JPEG: 3003 x 2324 pix - 436k] Caption to ESO PR Photo 37d/99 : This UVES echelle spectrum QSO HE2217-2818 (U-magnitude = 16.5) is recorded in different orders (the individual horizontal lines) and altogether covers the wavelength interval between 330 - 450 nm (from the bottom to the top). It illustrates the excellent capability of UVES to work in the UV-band on even faint targets. Simultaneously with this observation, UVES also recorded the adjacent spectral region 465 - 660 nm in its other channel. The broad Lyman-alpha emission from ionized hydrogen associated with the powerful energy source of the QSO is seen in the upper half of the spectrum at wavelength 413 nm. At shorter wavelengths, the dark regions in the spectrum are Lyman-alpha absorption lines from intervening, neutral hydrogen gas located along the line-of-sight at different redshifts (the so-called Lyman-alpha forest ) in the redshift interval z = 1.7 - 2.4. Note that since this exposure was done with the nearly Full Moon above the horizon, an underlying, faint absorption-line spectrum of reflected sunlight is also visible. Caption to ESO PR Photo 37e/99 : A tracing of one spectral order, corresponding to one horizontal line in the echelle spectrum displayed in PR Photo 37d/99 . It shows part of the Lyman-alpha forest in the ultraviolet spectrum of the southern quasar QSO HE2217-2818 . The absorption lines are caused by intervening, neutral hydrogen gas located at different distances along the line-of-sight towards this quasar. How to obtain ESO Press Information ESO Press Information is made available on the World-Wide Web (URL: http://www.eso.org../ ). ESO Press Photos may be reproduced, if credit is given to the European Southern Observatory.

Rac1 Recruitment to the Archipelago Structure of the Focal Adhesion through the Fluid Membrane as Revealed by Single-Molecule Analysis

PubMed Central

Shibata, Akihiro C E; Chen, Limin H; Nagai, Rie; Ishidate, Fumiyoshi; Chadda, Rahul; Miwa, Yoshihiro; Naruse, Keiji; Shirai, Yuki M; Fujiwara, Takahiro K; Kusumi, Akihiro

2013-01-01

The focal adhesion (FA) is an integrin-based structure built in/on the plasma membrane (PM), linking the extracellular matrix to the actin stress-fibers, working as cell migration scaffolds. Previously, we proposed the archipelago architecture of the FA, in which FA largely consists of fluid membrane, dotted with small islands accumulating FA proteins: membrane molecules enter the inter-island channels in the FA zone rather freely, and the integrins in the FA-protein islands rapidly exchanges with those in the bulk membrane. Here, we examined how Rac1, a small G-protein regulating FA formation, and its activators αPIX and βPIX, are recruited to the FA zones. PIX molecules are recruited from the cytoplasm to the FA zones directly. In contrast, majorities of Rac1 molecules first arrive from the cytoplasm on the general inner PM surface, and then enter the FA zones via lateral diffusion on the PM, which is possible due to rapid Rac1 diffusion even within the FA zones, slowed only by a factor of two to four compared with that outside. The constitutively-active Rac1 mutant exhibited temporary and all-time immobilizations in the FA zone, suggesting that upon PIX-induced Rac1 activation at the FA-protein islands, Rac1 tends to be immobilized at the FA-protein islands. © 2013 Wiley Periodicals, Inc PMID:23341328

Geomorphometric multi-scale analysis for the recognition of Moon surface features using multi-resolution DTMs

NASA Astrophysics Data System (ADS)

Li, Ke; Chen, Jianping; Sofia, Giulia; Tarolli, Paolo

2014-05-01

Moon surface features have great significance in understanding and reconstructing the lunar geological evolution. Linear structures like rilles and ridges are closely related to the internal forced tectonic movement. The craters widely distributed on the moon are also the key research targets for external forced geological evolution. The extremely rare availability of samples and the difficulty for field works make remote sensing the most important approach for planetary studies. New and advanced lunar probes launched by China, U.S., Japan and India provide nowadays a lot of high-quality data, especially in the form of high-resolution Digital Terrain Models (DTMs), bringing new opportunities and challenges for feature extraction on the moon. The aim of this study is to recognize and extract lunar features using geomorphometric analysis based on multi-scale parameters and multi-resolution DTMs. The considered digital datasets include CE1-LAM (Chang'E One, Laser AltiMeter) data with resolution of 500m/pix, LRO-WAC (Lunar Reconnaissance Orbiter, Wide Angle Camera) data with resolution of 100m/pix, LRO-LOLA (Lunar Reconnaissance Orbiter, Lunar Orbiter Laser Altimeter) data with resolution of 60m/pix, and LRO-NAC (Lunar Reconnaissance Orbiter, Narrow Angle Camera) data with resolution of 2-5m/pix. We considered surface derivatives to recognize the linear structures including Rilles and Ridges. Different window scales and thresholds for are considered for feature extraction. We also calculated the roughness index to identify the erosion/deposits area within craters. The results underline the suitability of the adopted methods for feature recognition on the moon surface. The roughness index is found to be a useful tool to distinguish new craters, with higher roughness, from the old craters, which present a smooth and less rough surface.

New results of GridPix TPCs

NASA Astrophysics Data System (ADS)

van der Graaf, Harry

2009-07-01

The Gossip detector, being a GridPix TPC equipped with a thin layer of gas, is a promising alternative for Si tracking detectors. In addition, GridPix would be an interesting way to read out the gaseous phase volume of bi-phase Liquid Xe cryostats of v-less double beta decay and rare event (i.e. WIMP) search experiments.

Further results from PIXE analysis of inks in Galileo's notes on motion

NASA Astrophysics Data System (ADS)

Del Carmine, P.; Giuntini, L.; Hooper, W.; Lucarelli, F.; Mandò, P. A.

1996-06-01

We have recently analysed the inks in some of the folios of Vol. 72 of Manoscritti galileiani, kept at the Biblioteca Nazionale Centrale di Firenze, which contains a collection of loose handwritten sheets containing undated notes, data from experiments and propositions on the problems of motion from different periods of Galileo's life. This paper reports specific results obtained from the analysis of some of these propositions, which allowed to make a contribution to their chronological attribution and therefore to the solution of some historical controversies. Even in the case where the "absolute" chronological attributions could not be made on the basis of comparison with dated documents, the PIXE results provided useful information to deny or confirm the hypothesis that different propositions were written in the same or in different periods.

Micro-PIXE analysis of trace element concentrations of natural rubies from different locations in Myanmar

NASA Astrophysics Data System (ADS)

Sanchez, J. L.; Osipowicz, T.; Tang, S. M.; Tay, T. S.; Win, T. T.

1997-07-01

The trace element concentrations found in geological samples can shed light on the formation process. In the case of gemstones, which might be of artificial or natural origin, there is also considerable interest in the development of methods that provide identification of the origin of a sample. For rubies, trace element concentrations present in natural samples were shown previously to be significant indicators of the region of origin [S.M. Tang et al., Appl. Spectr. 42 (1988) 44, and 43 (1989) 219]. Here we report the results of micro-PIXE analyses of trace element (Ti, V, Cr, Fe, Cu and Ga) concentrations of a large set ( n = 130) of natural rough rubies from nine locations in Myanmar (Burma). The resulting concentrations are subjected to statistical analysis. Six of the nine groups form clusters when the data base is evaluated using tree clustering and principal component analysis.

Recent developments of ion beam induced luminescence at the external scanning microbeam facility of the LABEC laboratory in Florence

NASA Astrophysics Data System (ADS)

Colombo, E.; Calusi, S.; Cossio, R.; Giuntini, L.; Giudice, A. Lo; Mandò, P. A.; Manfredotti, C.; Massi, M.; Mirto, F. A.; Vittone, E.

2008-04-01

A new ionoluminescence (IL) apparatus has been successfully installed at the external scanning microbeam facility of the 3 MV Tandetron accelerator of the INFN LABEC in Firenze; the apparatus for photon detection has been fully integrated in the existing ion beam analysis (IBA) set-up, for the simultaneous acquisition of IL and PIXE/PIGE/BS spectra and maps. The potential of the new set-up is illustrated in this paper by some results extracted by the analysis of art objects and advanced semiconductor materials. In particular, the adequacy of the new IBA set-up in the field of cultural heritage is pointed out by the coupled PIXE/IL micro-analysis of a lapis lazuli stone; concerning applications in material science, IL spectra from a N doped diamond sample were acquired and compared with CL analyses to evaluate the relevant sensitivities and the effect of ion damage.

Six stirrup handled Moche ceramic vessels from pre-Colombian Peru: a technical study applying PIXE spectrometry

NASA Astrophysics Data System (ADS)

Swann, C. P.; Caspi, Sara; Carlson, Janice

1999-04-01

Much has been said recently concerning the Moche culture of Peru (100 B.C. to 700 A.D. ) which preceded the more widely known Inca society. Since there was no written language, what is known about the Moche people has been through the artifacts produced, their design and craftsmanship. This study concerns the PIXE analysis of the matrix and the red and white surface patterns of six stirrup handled earthenware vessels. The results suggest different techniques were applied for producing the coloring and surface designs and that a common source of clays was not used in the construction.

Micro-PIXE evaluation of radioactive cesium transfer in contaminated soil samples

NASA Astrophysics Data System (ADS)

Fujishiro, F.; Ishii, K.; Matsuyama, S.; Arai, H.; Ishizaki, A.; Osada, N.; Sugai, H.; Kusano, K.; Nozawa, Y.; Yamauchi, S.; Karahashi, M.; Oshikawa, S.; Kikuchi, K.; Koshio, S.; Watanabe, K.; Suzuki, Y.

2014-01-01

Micro-PIXE analysis has been performed on two soil samples with high cesium activity concentrations. These soil samples were contaminated by fallout from the accident at Fukushima Daiichi Nuclear Power Plant. One exhibits a radioactive cesium transfer of ˜0.01, and the other shows a radioactive cesium transfer of less than 0.001, even though both samples have high cesium activity concentrations exceeding 10,000 Bq/kg. X-ray spectra and elemental images of the soil samples revealed the presence of chlorine, which can react with cesium to produce an inorganic soluble compound, and phosphorus-containing cesium-capturable organic compounds.

Applications of condensed matter understanding to medical tissues and disease progression: Elemental analysis and structural integrity of tissue scaffolds

NASA Astrophysics Data System (ADS)

Bradley, D. A.; Farquharson, M. J.; Gundogdu, O.; Al-Ebraheem, Alia; Che Ismail, Elna; Kaabar, W.; Bunk, O.; Pfeiffer, F.; Falkenberg, G.; Bailey, M.

2010-02-01

The investigations reported herein link tissue structure and elemental presence with issues of environmental health and disease, exemplified by uptake and storage of potentially toxic elements in the body, the osteoarthritic condition and malignancy in the breast and other soft tissues. Focus is placed on application of state-of-the-art ionizing radiation techniques, including, micro-synchrotron X-ray fluorescence (μ-SXRF) and particle-induced X-ray emission/Rutherford backscattering mapping (μ-PIXE/RBS), coherent small-angle X-ray scattering (cSAXS) and X-ray phase-contrast imaging, providing information on elemental make-up, the large-scale organisation of collagen and anatomical features of moderate and low atomic number media. For the particular situations under investigation, use of such facilities is allowing information to be obtained at an unprecedented level of detail, yielding new understanding of the affected tissues and the progression of disease.

Large Area Coverage of a TPC Endcap with GridPix Detectors

NASA Astrophysics Data System (ADS)

Kaminski, Jochen

2018-02-01

The Large Prototype TPC at DESY, Hamburg, was built by the LCTPC collaboration as a testbed for new readout technologies of Time Projection Chambers. Up to seven modules of about 400 cm2 each can be placed in the endcap. Three of these modules were equipped with a total of 160 GridPix detectors. This is a combination of a highly pixelated readout ASIC and a Micromegas built on top. GridPix detectors have a very high efficiency of detecting primary electrons, which leads to excellent spatial and energy resolutions. For the first time a large number of GridPix detectors has been operated and long segments of tracks have been recorded with excellent precision.

The PIX-2 experiment: An overview

NASA Astrophysics Data System (ADS)

Purvis, C. K.

1985-03-01

The second Plasma Interactions Experiment (PIX-2) was launched in January 1983 as a piggyback on the second stage of the Delta launch vehicle that carried IRAS into orbit. Placed in a 870 km circular polar orbit, it returned 18 hrs of data on the plasma current collection and arcing behavior of solar arrays biased to +/-1000 V in steps. The four 500 sq cm solar array segments were biased singly and in combinations. In addition to the array segments PIX-2 carried a Sun sensor, a Langmuir probe to measure electron currents, and a hot-wire filament electron emitter to control vehicle potential during positive array bias sequences. The PIX-2 experiment is reviewed from program and operational perspectives.

CdTe detector based PIXE mapping of geological samples

NASA Astrophysics Data System (ADS)

Chaves, P. C.; Taborda, A.; de Oliveira, D. P. S.; Reis, M. A.

2014-01-01

A sample collected from a borehole drilled approximately 10 km ESE of Bragança, Trás-os-Montes, was analysed by standard and high energy PIXE at both CTN (previous ITN) PIXE setups. The sample is a fine-grained metapyroxenite grading to coarse-grained in the base with disseminated sulphides and fine veinlets of pyrrhotite and pyrite. Matrix composition was obtained at the standard PIXE setup using a 1.25 MeV H+ beam at three different spots. Medium and high Z elemental concentrations were then determined using the DT2fit and DT2simul codes (Reis et al., 2008, 2013 [1,2]), on the spectra obtained in the High Resolution and High Energy (HRHE)-PIXE setup (Chaves et al., 2013 [3]) by irradiation of the sample with a 3.8 MeV proton beam provided by the CTN 3 MV Tandetron accelerator. In this paper we present results, discuss detection limits of the method and the added value of the use of the CdTe detector in this context.

Characterization of the ePix100 prototype: a front-end ASIC for second-generation LCLS integrating hybrid pixel detectors

NASA Astrophysics Data System (ADS)

Caragiulo, P.; Dragone, A.; Markovic, B.; Herbst, R.; Nishimura, K.; Reese, B.; Herrmann, S.; Hart, P.; Blaj, G.; Segal, J.; Tomada, A.; Hasi, J.; Carini, G.; Kenney, C.; Haller, G.

2014-09-01

ePix100 is the first variant of a novel class of integrating pixel ASICs architectures optimized for the processing of signals in second generation LINAC Coherent Light Source (LCLS) X-Ray cameras. ePix100 is optimized for ultra-low noise application requiring high spatial resolution. ePix ASICs are based on a common platform composed of a random access analog matrix of pixel with global shutter, fast parallel column readout, and dedicated sigma-delta analog to digital converters per column. The ePix100 variant has 50μmx50μm pixels arranged in a 352x384 matrix, a resolution of 50e- r.m.s. and a signal range of 35fC (100 photons at 8keV). In its final version it will be able to sustain a frame rate of 1kHz. A first prototype has been fabricated and characterized and the measurement results are reported here.

ePix: a class of architectures for second generation LCLS cameras

DOE PAGES

Dragone, A.; Caragiulo, P.; Markovic, B.; ...

2014-03-31

ePix is a novel class of ASIC architectures, based on a common platform, optimized to build modular scalable detectors for LCLS. The platform architecture is composed of a random access analog matrix of pixel with global shutter, fast parallel column readout, and dedicated sigma-delta analog-to-digital converters per column. It also implements a dedicated control interface and all the required support electronics to perform configuration, calibration and readout of the matrix. Based on this platform a class of front-end ASICs and several camera modules, meeting different requirements, can be developed by designing specific pixel architectures. This approach reduces development time andmore » expands the possibility of integration of detector modules with different size, shape or functionality in the same camera. The ePix platform is currently under development together with the first two integrating pixel architectures: ePix100 dedicated to ultra low noise applications and ePix10k for high dynamic range applications.« less

Identification and characterization of fine and coarse particulate matter sources in a middle-European urban environment

NASA Astrophysics Data System (ADS)

Kertész, Zs.; Szoboszlai, Z.; Angyal, A.; Dobos, E.; Borbély-Kiss, I.

2010-06-01

In this work a source apportionment study is presented which aimed to characterize the PM 2.5 and PM 2.5-10 sources in the urban area of Debrecen, East-Hungary by using streaker samples, IBA methods and positive matrix factorization (PMF) analysis. Samples of fine (PM 2.5) and coarse (PM 2.5-10) urban particulate matter were collected with 2 h time resolution in the frame of five sampling campaigns during 2007-2009 in different seasons in the downtown of Debrecen. Elemental concentrations from Al to Pb of over 1000 samples were obtained by particle induced X-ray emission (PIXE); concentrations of black carbon (BC) were determined with a smoke stain reflectometer. On this data base source apportionment was carried out by using the PMF method. Seven factors were identified for both size fractions, including soil dust, traffic, secondary aerosol - sulphates, domestic heating, oil combustion, agriculture and an unknown factor enriched with chlorine. Seasonal and daily variation of the different factors was studied as well as their dependence on meteorological parameters. Besides determining the time patterns characteristic to the city, several emission episodes were identified including a Saharan dust intrusion on 21st-24th May, 2008.

Background considerations in the analysis of PIXE spectra by Artificial Neural Systems.

NASA Astrophysics Data System (ADS)

Correa, R.; Morales, J. R.; Requena, I.; Miranda, J.; Barrera, V. A.

2016-05-01

In order to study the importance of background in PIXE spectra to determine elemental concentrations in atmospheric aerosols using artificial neural systems ANS, two independently trained ANS were constructed, one which considered as input the net number of counts in the peak, and another which included the background. In the training and validation phases thirty eight spectra of aerosols collected in Santiago, Chile, were used. In both cases the elemental concentration values were similar. This fact was due to the intrinsic characteristic of ANS operating with normalized values of the net and total number of counts under the peaks, something that was verified in the analysis of 172 spectra obtained from aerosols collected in Mexico city. Therefore, networks operating under the mode which include background can reduce time and cost when dealing with large number of samples.

Elemental X-ray Imaging Using the Maia Detector Array: The Benefits and Challenges of Large Solid-Angle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryan, C.G.; De Geronimo, G.; Kirkham, R.

2009-11-13

The fundamental parameter method for quantitative SXRF and PIXE analysis and imaging using the dynamic analysis method is extended to model the changing X-ray yields and detector sensitivity with angle across large detector arrays. The method is implemented in the GeoPIXE software and applied to cope with the large solid-angle of the new Maia 384 detector array and its 96 detector prototype developed by CSIRO and BNL for SXRF imaging applications at the Australian and NSLS synchrotrons. Peak-to-background is controlled by mitigating charge-sharing between detectors through careful optimization of a patterned molybdenum absorber mask. A geological application demonstrates the capabilitymore » of the method to produce high definition elemental images up to {approx}100 M pixels in size.« less

Accelerator-based analytical technique in the evaluation of some Nigeria’s natural minerals: Fluorite, tourmaline and topaz

NASA Astrophysics Data System (ADS)

Olabanji, S. O.; Ige, O. A.; Mazzoli, C.; Ceccato, D.; Akintunde, J. A.; De Poli, M.; Moschini, G.

2005-10-01

For the first time, the complementary accelerator-based analytical technique of PIXE and electron microprobe analysis (EMPA) were employed for the characterization of some Nigeria's natural minerals namely fluorite, tourmaline and topaz. These minerals occur in different areas in Nigeria. The minerals are mainly used as gemstones and for other scientific and technological applications and therefore are very important. There is need to characterize them to know the quality of these gemstones and update the geochemical data on them geared towards useful applications. PIXE analysis was carried out using the 1.8 MeV collimated proton beam from the 2.5 MV AN 2000 Van de Graaff accelerator at INFN, LNL, Legnaro, Padova, Italy. The novel results which show many elements at different concentrations in these minerals are presented and discussed.

The Australian millipede Dicranogonus pix Jeekel, 1982 (Diplopoda, Polydesmida, Paradoxosomatidae): a species with and without paranota

PubMed Central

Mesibov, Robert

2014-01-01

Abstract Dicranogonus pix Jeekel, 1982 occurs in Victoria and Tasmania, Australia, including the islands in eastern Bass Strait between the two States. There is only slight gonopod variation across this range, but Dicranogonus pix populations with and without paranota are separated in Bass Strait by the ca 50 km-wide gap between the Kent and Furneaux Groups of islands. PMID:25493065

Role of phospholipase Cgamma1 in cell spreading requires association with a beta-Pix/GIT1-containing complex, leading to activation of Cdc42 and Rac1.

PubMed

Jones, Neil P; Katan, Matilda

2007-08-01

The significance of multiprotein signaling complexes in cell motility is becoming increasingly important. We have previously shown that phospholipase Cgamma1 (PLCgamma1) is critical for integrin-mediated cell spreading and motility (N. Jones et al., J. Cell Sci. 118:2695-2706, 2005). In the current study we show that, on a basement membrane-type matrix, PLCgamma1 associates with the adaptor protein GIT1 and the Rac1/Cdc42 guanine exchange factor beta-Pix; GIT1 and beta-Pix form tight complexes independently of PLCgamma1. The association of PLCgamma1 with the complex requires both GIT1 and beta-Pix and the specific array region (gammaSA) of PLCgamma1. Mutations of PLCgamma1 within the gammaSA region reveal that association with this complex is essential for the phosphorylation of PLCgamma1 and the progression to an elongated morphology after integrin engagement. Short interfering RNA (siRNA) depletion of either beta-Pix or GIT1 inhibited cell spreading in a fashion similar to that seen with siRNA against PLCgamma1. Furthermore, siRNA depletion of PLCgamma1, beta-Pix, or GIT1 inhibited Cdc42 and Rac1 activation, while constitutively active forms of Cdc42 or Rac1, but not RhoA, were able to rescue the elongation of these cells. Signaling of the PLCgamma1/GIT1/beta-Pix complex to Cdc42/Rac1 was found to involve the activation of calpains, calcium-dependent proteases. Therefore, we propose that the association of PLCgamma1 with complexes containing GIT1 and beta-Pix is essential for its role in integrin-mediated cell spreading and motility. As a component of this complex, PLCgamma1 is also involved in the activation of Cdc42 and Rac1.

External-beam PIXE spectrometry for the study of Punic jewellery (SW Spain): The geographical provenance of the palladium-bearing gold

NASA Astrophysics Data System (ADS)

Ontalba Salamanca, M. Á.; Gómez-Tubío, B.; Ortega-Feliu, I.; Respaldiza, M. Á.; Luisa de la Bandera, M.; Ovejero Zappino, G.; Bouzas, A.; Gómez-Morón, A.

2006-08-01

This paper presents the study of a set of Punic gold items (400 B.C.), from the Museum of Cádiz (Spain). An external beam set-up has been employed for the absolutely non-destructive analysis of the objects. PIXE spectrometry has been performed in order to characterize the metallic alloys and the manufacturing techniques. Compositional differences have been found and soldering procedures have been identified. By comparison with the rings and other coetaneous jewellery, the presence of palladium in the bulk alloy of the earrings can be pointed out. The geographical provenance of the palladium-bearing gold is discussed based on geological and archaeological considerations.

Application of PIXE to study ancient Iranian silver coins

NASA Astrophysics Data System (ADS)

Hajivaliei, M.; Mohammadifar, Y.; Ghiyasi, K.; Jaleh, B.; Lamehi-Rachti, M.; Oliaiy, P.

2008-04-01

A number of ancient Iranian silver coins belonging to Khosrau II (592-626 A.D.) minted during Sasanians dynasty were analyzed using proton induced X-ray emission (PIXE) technique. The 2 MeV proton beam with a current of 2-3 nA from AEOI, Van de Graaff accelerator was used to bombard the coins. The characteristic X-rays emitted from the samples, were detected by a Si(Li) detector from ORTEC with an energy resolution of 170 eV at 5.9 keV. The detector was placed in the beam direction at 135°. The elements Cl, Ca, Ti, Mn, Fe, Cu, Au and Pb were observed in the coins along with the major component silver. The percentage of silver varied between 85.87 and 93.39%. The possible correlation between the composition of coins and the minting time or the minting location of coins was the prime goal. There was a negative correlation between copper and silver. The weight of coins varied between 4.02 and 4.30 g. Going through the results, it seems that the local mines were used to die-strike the coins. The obtained results are in good agreement with archaeological records.

First-time observation of Mastro Giorgio masterpieces by means of non-destructive techniques

NASA Astrophysics Data System (ADS)

Padeletti, G.; Ingo, G. M.; Bouquillon, A.; Pages-Camagna, S.; Aucouturier, M.; Roehrs, S.; Fermo, P.

2006-06-01

For the first time some excellent pieces belonging to the majolica production of the great master Giorgio Andreoli from Gubbio (Central Italy) have been characterized from a chemical and structural point of view with the aim to identify the composition of both pigments and lustres. A series of particle-induced X-ray emission (PIXE), Rutherford backscattering spectrometry (RBS) and Raman analyses have been performed on some plates coming from Museo del Palazzo dei Consoli (Gubbio) and several French museums (Louvre, Musée National de la Céramique, Musée National de la Renaissance) lustred by Giorgio Andreoli and decorated by famous majolica painters such as Francesco Xanto Avelli. The three techniques are complementary and useful in the investigation of art objects since they are non-destructive. Furthermore, the low detection limits allow the identification of all elements and compounds present, and RBS allows concentration profiling, too. It is worth noticing that the examined objects are characterized by the presence of both gold and ruby-red lustres, a peculiarity of Mastro Giorgio’s technique. The measurements by PIXE and RBS have been carried out on the AGLAE accelerator at C2RMF, Louvre Palace.

New Paranal Views

NASA Astrophysics Data System (ADS)

2001-01-01

Last year saw very good progress at ESO's Paranal Observatory , the site of the Very Large Telescope (VLT). The third and fourth 8.2-m Unit Telescopes, MELIPAL and YEPUN had "First Light" (cf. PR 01/00 and PR 18/00 ), while the first two, ANTU and KUEYEN , were busy collecting first-class data for hundreds of astronomers. Meanwhile, work continued towards the next phase of the VLT project, the combination of the telescopes into the VLT Interferometer. The test instrument, VINCI (cf. PR 22/00 ) is now being installed in the VLTI Laboratory at the centre of the observing platform on the top of Paranal. Below is a new collection of video sequences and photos that illustrate the latest developments at the Paranal Observatory. The were obtained by the EPR Video Team in December 2000. The photos are available in different formats, including "high-resolution" that is suitable for reproduction purposes. A related ESO Video News Reel for professional broadcasters will soon become available and will be announced via the usual channels. Overview Paranal Observatory (Dec. 2000) Video Clip 02a/01 [MPEG - 4.5Mb] ESO PR Video Clip 02a/01 "Paranal Observatory (December 2000)" (4875 frames/3:15 min) [MPEG Video+Audio; 160x120 pix; 4.5Mb] [MPEG Video+Audio; 320x240 pix; 13.5 Mb] [RealMedia; streaming; 34kps] [RealMedia; streaming; 200kps] ESO Video Clip 02a/01 shows some of the construction activities at the Paranal Observatory in December 2000, beginning with a general view of the site. Then follow views of the Residencia , a building that has been designed by Architects Auer and Weber in Munich - it integrates very well into the desert, creating a welcome recreational site for staff and visitors in this harsh environment. The next scenes focus on the "stations" for the auxiliary telescopes for the VLTI and the installation of two delay lines in the 140-m long underground tunnel. The following part of the video clip shows the start-up of the excavation work for the 2.6-m VLT Survey Telescope (VST) as well as the location known as the "NTT Peak", now under consideration for the installation of the 4-m VISTA telescope. The last images are from to the second 8.2-m Unit Telescope, KUEYEN, that has been in full use by the astronomers with the UVES and FORS2 instruments since April 2000. ESO PR Photo 04a/01 ESO PR Photo 04a/01 [Preview - JPEG: 466 x 400 pix - 58k] [Normal - JPEG: 931 x 800 pix - 688k] [Hires - JPEG: 3000 x 2577 pix - 7.6M] Caption : PR Photo 04a/01 shows an afternoon view from the Paranal summit towards East, with the Base Camp and the new Residencia on the slope to the right, above the valley in the shadow of the mountain. ESO PR Photo 04b/01 ESO PR Photo 04b/01 [Preview - JPEG: 791 x 400 pix - 89k] [Normal - JPEG: 1582 x 800 pix - 1.1Mk] [Hires - JPEG: 3000 x 1517 pix - 3.6M] PR Photo 04b/01 shows the ramp leading to the main entrance to the partly subterranean Residencia , with the steel skeleton for the dome over the central area in place. ESO PR Photo 04c/01 ESO PR Photo 04c/01 [Preview - JPEG: 498 x 400 pix - 65k] [Normal - JPEG: 995 x 800 pix - 640k] [Hires - JPEG: 3000 x 2411 pix - 6.6M] PR Photo 04c/01 is an indoor view of the reception hall under the dome, looking towards the main entrance. ESO PR Photo 04d/01 ESO PR Photo 04d/01 [Preview - JPEG: 472 x 400 pix - 61k] [Normal - JPEG: 944 x 800 pix - 632k] [Hires - JPEG: 3000 x 2543 pix - 5.8M] PR Photo 04d/01 shows the ramps from the reception area towards the rooms. The VLT Interferometer The Delay Lines consitute a most important element of the VLT Interferometer , cf. PR Photos 26a-e/00. At this moment, two Delay Lines are operational on site. A third system will be integrated early this year. The VLTI Delay Line is located in an underground tunnel that is 168 metres long and 8 metres wide. This configuration has been designed to accommodate up to eight Delay Lines, including their transfer optics in an ideal environment: stable temperature, high degree of cleanliness, low levels of straylight, low air turbulence. The positions of the Delay Line carriages are computed to adjust the Optical Path Lengths requested for the fringe pattern observation. The positions are controlled in real time by a laser metrology system, specially developed for this purpose. The position precision is about 20 nm (1 nm = 10 -9 m, or 1 millionth of a millimetre) over a distance of 120 metres. The maximum velocity is 0.50 m/s in position mode and maximum 0.05 m/s in operation. The system is designed for 25 year of operation and to survive earthquake up to 8.6 magnitude on the Richter scale. The VLTI Delay Line is a three-year project, carried out by ESO in collaboration with Dutch Space Holdings (formerly Fokker Space) and TPD-TNO . VLTI Delay Lines (December 2000) - ESO PR Video Clip 02b/01 [MPEG - 3.6Mb] ESO PR Video Clip 02b/01 "VLTI Delay Lines (December 2000)" (2000 frames/1:20 min) [MPEG Video+Audio; 160x120 pix; 3.6Mb] [MPEG Video+Audio; 320x240 pix; 13.7 Mb] [RealMedia; streaming; 34kps] [RealMedia; streaming; 200kps] ESO Video Clip 02b/00 shows the Delay Lines of the VLT Interferometer facility at Paranal during tests. One of the carriages is moving on 66-metre long rectified rails, driven by a linear motor. The carriage is equipped with three wheels in order to preserve high guidance accuracy. Another important element is the Cat's Eye that reflects the light from the telescope to the VLT instrumentation. This optical system is made of aluminium (including the mirrors) to avoid thermo-mechanical problems. ESO PR Photo 04e/01 ESO PR Photo 04e/01 [Preview - JPEG: 400 x 402 pix - 62k] [Normal - JPEG: 800 x 804 pix - 544k] [Hires - JPEG: 3000 x 3016 pix - 6.2M] Caption : PR Photo 04e/01 shows one of the 30 "stations" for the movable 1.8-m Auxiliary Telescopes. When one of these telescopes is positioned ("parked") on top of it, The light will be guided through the hole towards the Interferometric Tunnel and the Delay Lines. ESO PR Photo 04f/01 ESO PR Photo 04f/01 [Preview - JPEG: 568 x 400 pix - 96k] [Normal - JPEG: 1136 x 800 pix - 840k] [Hires - JPEG: 3000 x 2112 pix - 4.6M] PR Photo 04f/01 shows a general view of the Interferometric Tunnel and the Delay Lines. ESO PR Photo 04g/01 ESO PR Photo 04g/01 [Preview - JPEG: 406 x 400 pix - 62k] [Normal - JPEG: 812 x 800 pix - 448k] [Hires - JPEG: 3000 x 2956 pix - 5.5M] PR Photo 04g/01 shows one of the Delay Line carriages in parking position. The "NTT Peak" The "NTT Peak" is a mountain top located about 2 km to the north of Paranal. It received this name when ESO considered to move the 3.58-m New Technology Telescope from La Silla to this peak. The possibility of installing the 4-m VISTA telescope (cf. PR 03/00 ) on this peak is now being discussed. ESO PR Photo 04h/01 ESO PR Photo 04h/01 [Preview - JPEG: 630 x 400 pix - 89k] [Normal - JPEG: 1259 x 800 pix - 1.1M] [Hires - JPEG: 3000 x 1907 pix - 5.2M] PR Photo 04h/01 shows the view from the "NTT Peak" towards south, vith the Paranal mountain and the VLT enclosures in the background. ESO PR Photo 04i/01 ESO PR Photo 04i/01 [Preview - JPEG: 516 x 400 pix - 50k] [Normal - JPEG: 1031 x 800 pix - 664k] [Hires - JPEG: 3000 x 2328 pix - 6.0M] PR Photo 04i/01 is a view towards the "NTT Peak" from the top of the Paranal mountain. The access road and the concrete pillar that was used to support a site testing telescope at the top of this peak are seen This is the caption to ESO PR Photos 04a-1/01 and PR Video Clips 02a-b/01 . They may be reproduced, if credit is given to the European Southern Observatory. The ESO PR Video Clips service to visitors to the ESO website provides "animated" illustrations of the ongoing work and events at the European Southern Observatory. The most recent clip was: ESO PR Video Clip 01/01 about the Physics On Stage Festival (11 January 2001) . Information is also available on the web about other ESO videos.

Charged particle induced delayed X-rays (DEX) for the analysis of intermediate and heavy elements

NASA Astrophysics Data System (ADS)

Pillay, A. E.; Erasmus, C. S.; Andeweg, A. H.; Sellschop, J. P. F.; Annegarn, H. J.; Dunn, J.

1988-12-01

The emission of K X-rays from proton-rich and metastable radionuclides, following proton activation of the stable isotopes of the elements of interest, has not been widely used as a means of analysis. The thrust of this paper proposes a nuclear technique using delayed X-rays for the analysis of low concentrations of intermediate and heavy elements. The method is similar to the delayed gamma-ray technique. Proton bombardment induces mainly (p, n) reactions whereas the delayed X-rays originate largely from e --capture and isomeric transition. Samples of rare earth and platinum group elements (PGE), in the form of compacted powders, were irradiated with an 11 MeV proton beam and delayed X-rays detected with a 100 mm 2 Ge detector. Single element spectra for a range of rare earths and PGEs are presented. Analytical conditions are demonstrated for Pd in the range 0.1-5%. Spectra from actual geological samples of a PGE ore, preconcentrated by fire-assay, and monazite are presented. All six platinum group elements are visible and interference-free in a single spectrum, a marked advance on other nuclear techniques for these elements, including PIXE and neutron activation analysis (NAA).

Size-Segregated Aerosol Composition and Mass Loading of Atmospheric Particles as Part of the Pacific Northwest 2001(PNW2001) Air Quality Study In Puget Sound

NASA Astrophysics Data System (ADS)

Disselkamp, R. S.; Barrie, L. A.; Shutthanadan, S.; Cliff, S.; Cahill, T.

2001-12-01

In mid-August, 2001, an aircraft-based air-quality study was performed in the Puget Sound, WA, area entitled PNW2001 (http://www.pnl.gov/pnw2001). The objectives of this field campaign were the following: 1. reveal information about the 3-dimensional distribution of ozone, its gaseous precursors and fine particulate matter during weather conditions favoring air pollution; 2. derive information about the accuracy of urban and biogenic emissions inventories that are used to drive the air quality forecast models; and 3. examine the accuracy of modeled ozone concentration with that observed. In support of these efforts, we collected time-averaged ( { ~}10 minute averages), size-segregated, aerosol composition and mass-loading information using ex post facto analysis techniques of synchrotron x-ray fluorescence (s-XRF), proton induced x-ray emissions(PIXE), proton elastic scattering (PESA), and scanning transmission ion microscopy (STIM). This is the first time these analysis techniques have been used together on samples collected from aircraft using an optimized 3-stage rotating drum impactor. In our presentation, we will discuss the aerosol components in three aerosol size fractions as identified by statistical analysis of multielemental data (including total mass, H, Na, Mg, Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Pb) and relate variations in these components to physical aerosol properties, other gaseous trace constituents and to air mass origin.

Trace element analysis by PIXE in several biomedical fields

NASA Astrophysics Data System (ADS)

Weber, G.; Robaye, G.; Bartsch, P.; Collignon, A.; Beguin, Y.; Roelandts, I.; Delbrouck, J. M.

1984-04-01

Since 1980 in the University of Liége trace element analysis by PIXE has been developed in several directions, among these: the elemental composition of lung parenchyma, hilar lymph nodes, blood content in hematological disorders and renal insufficiency. The content in trace elements of lung tumor and surrounding tissue is measured and compared to similar content previously obtained on unselected patients of comparable ages. The normalization of the bromine deficiency observed in hemodialized patients is achieved by using a dialyzing bath doped with NaBr in order to obtain a normal bromine level of 5.7 μg/ml. The content of Cu, Zn, Br and Se in blood serum from more than 100 patients suffering from malignant hemopathy has been measured. The results are compared with a reference group. These oligoelements have also been measured sequentially for patients under intensive chemotherapy in acute myeloid leukemia.

Trends and sources for heavy metals in urban atmosphere

NASA Astrophysics Data System (ADS)

Kemp, Kåre

2002-04-01

The concentrations of a number of heavy metals in the air in three Danish cities have been measured by means of PIXE for more than two decades. The well-known capability of PIXE for fast and efficient analysis of aerosol samples has been employed for analysis of daily samples from several sites during the whole period. The main sources are traffic, domestic heating and long-range transport. Source apportionment and trends for single metals are assessed by means of simple statistical methods. The most striking change has occurred for the Pb concentration, which is reduced by almost a factor of 100 following the reduction of the Pb content in petrol. The main source of Cu, Cr and Zn is the traffic. The concentrations of these elements have been slightly increasing. The concentrations for most of the other heavy metals, which originate mainly from sources outside the cities, have been decreasing.

An efficient approach to integrated MeV ion imaging.

PubMed

Nikbakht, T; Kakuee, O; Solé, V A; Vosuoghi, Y; Lamehi-Rachti, M

2018-03-01

An ionoluminescence (IL) spectral imaging system, besides the common MeV ion imaging facilities such as µ-PIXE and µ-RBS, is implemented at the Van de Graaff laboratory of Tehran. A versatile processing software is required to handle the large amount of data concurrently collected in µ-IL and common MeV ion imaging measurements through the respective methodologies. The open-source freeware PyMca, with image processing and multivariate analysis capabilities, is employed to simultaneously process common MeV ion imaging and µ-IL data. Herein, the program was adapted to support the OM_DAQ listmode data format. The appropriate performance of the µ-IL data acquisition system is confirmed through a case study. Moreover, the capabilities of the software for simultaneous analysis of µ-PIXE and µ-RBS experimental data are presented. Copyright © 2017 Elsevier B.V. All rights reserved.

Particulate sulfur in the upper troposphere and lowermost stratosphere - sources and climate forcing

NASA Astrophysics Data System (ADS)

Martinsson, Bengt G.; Friberg, Johan; Sandvik, Oscar S.; Hermann, Markus; van Velthoven, Peter F. J.; Zahn, Andreas

2017-09-01

This study is based on fine-mode aerosol samples collected in the upper troposphere (UT) and the lowermost stratosphere (LMS) of the Northern Hemisphere extratropics during monthly intercontinental flights at 8.8-12 km altitude of the IAGOS-CARIBIC platform in the time period 1999-2014. The samples were analyzed for a large number of chemical elements using the accelerator-based methods PIXE (particle-induced X-ray emission) and PESA (particle elastic scattering analysis). Here the particulate sulfur concentrations, obtained by PIXE analysis, are investigated. In addition, the satellite-borne lidar aboard CALIPSO is used to study the stratospheric aerosol load. A steep gradient in particulate sulfur concentration extends several kilometers into the LMS, as a result of increasing dilution towards the tropopause of stratospheric, particulate sulfur-rich air. The stratospheric air is diluted with tropospheric air, forming the extratropical transition layer (ExTL). Observed concentrations are related to the distance to the dynamical tropopause. A linear regression methodology handled seasonal variation and impact from volcanism. This was used to convert each data point into stand-alone estimates of a concentration profile and column concentration of particulate sulfur in a 3 km altitude band above the tropopause. We find distinct responses to volcanic eruptions, and that this layer in the LMS has a significant contribution to the stratospheric aerosol optical depth and thus to its radiative forcing. Further, the origin of UT particulate sulfur shows strong seasonal variation. We find that tropospheric sources dominate during the fall as a result of downward transport of the Asian tropopause aerosol layer (ATAL) formed in the Asian monsoon, whereas transport down from the Junge layer is the main source of UT particulate sulfur in the first half of the year. In this latter part of the year, the stratosphere is the clearly dominating source of particulate sulfur in the UT during times of volcanic influence and under background conditions.

A Horizontal Multi-Purpose Microbeam System.

PubMed

Xu, Y; Randers-Pehrson, G; Marino, S A; Garty, G; Harken, A; Brenner, D J

2018-04-21

A horizontal multi-purpose microbeam system with a single electrostatic quadruplet focusing lens has been developed at the Columbia University Radiological Research Accelerator Facility (RARAF). It is coupled with the RARAF 5.5 MV Singleton accelerator (High Voltage Engineering Europa, the Netherlands) and provides micrometer-size beam for single cell irradiation experiments. It is also used as the primary beam for a neutron microbeam and microPIXE (particle induced x-ray emission) experiment because of its high particle fluence. The optimization of this microbeam has been investigated with ray tracing simulations and the beam spot size has been verified by different measurements.

A horizontal multi-purpose microbeam system

NASA Astrophysics Data System (ADS)

Xu, Y.; Randers-Pehrson, G.; Marino, S. A.; Garty, G.; Harken, A.; Brenner, D. J.

2018-04-01

A horizontal multi-purpose microbeam system with a single electrostatic quadruplet focusing lens has been developed at the Columbia University Radiological Research Accelerator Facility (RARAF). It is coupled with the RARAF 5.5 MV Singleton accelerator (High Voltage Engineering Europa, the Netherlands) and provides micrometer-size beam for single cell irradiation experiments. It is also used as the primary beam for a neutron microbeam and microPIXE (particle induced x-ray emission) experiment because of its high particle fluence. The optimization of this microbeam has been investigated with ray tracing simulations and the beam spot size has been verified by different measurements.

Hourly elemental concentrations in PM2.5 aerosols sampled simultaneously at urban background and road site

NASA Astrophysics Data System (ADS)

Dall'Osto, M.; Querol, X.; Amato, F.; Karanasiou, A.; Lucarelli, F.; Nava, S.; Calzolai, G.; Chiari, M.

2012-08-01

Hourly-resolved aerosol chemical speciation data can be a highly powerful tool to determine the source origin of atmospheric pollutants in urban Environments. Aerosol mass concentrations of seventeen elements (Na, Mg, Al, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr and Pb) were obtained by time (1 h) and size (PM2.5 particulate matter <2.5 μm) resolved Particle Induced X-ray Emission (PIXE) measurements. In the Marie Curie FP7-EU framework of SAPUSS (Solving Aerosol Problems by Using Synergistic Strategies), the unique approach used is the simultaneous PIXE measurements at two monitoring sites: urban background (UB) and a street canyon traffic road site (RS). Elements related to primary non exhaust traffic emission (Fe, Cu), dust resuspension (Ca) and anthropogenic Cl were found enhanced at the RS, whereas industrial related trace metals (Zn, Pb, Mn) were found at higher concentrations at the more ventilated UB site. When receptor modelling was performed with positive matrix factorization (PMF), nine different aerosol sources were identified at both sites: three types of regional aerosols (secondary sulphate (S) - 27%, biomass burning (K) - 5%, sea salt (Na-Mg) - 17%), three types of dust aerosols (soil dust (Al-Ti) - 17%, urban crustal dust (Ca) - 6%, and primary traffic non exhaust brake dust (Fe-Cu) - 7%), and three types industrial aerosol plumes-like events (shipping oil combustion (V-Ni) - 17%, industrial smelters (Zn-Mn) - 3%, and industrial combustion (Pb-Cl) - 5%). The validity of the PMF solution of the PIXE data is supported by strong correlations with external single particle mass spectrometry measurements. Beside apportioning the aerosol sources, some important air quality related conclusions can be drawn about the PM2.5 fraction simultaneously measured at the UB and RS sites: (1) the regional aerosol sources impact both monitoring sites at similar concentrations regardless their different ventilation conditions; (2) by contrast, local industrial aerosol plumes associated with shipping oil combustion and smelters activities have a higher impact on the more ventilated UB site; (3) a unique source of Pb-Cl (associated with industrial combustion emissions) is found a to be the major (82%) source of Cl in the urban agglomerate; (4) PM2.5 traffic brake dust (Fe-Cu) is mainly primarily emitted and not resuspended, whereas PM2.5 urban crustal dust (Ca) is found mainly resuspended by both traffic vortex and sea breeze; (5) urban dust (Ca) is found the aerosol source most affected by land wetness, reduced by a factor of eight during rainy days and suggesting that wet roads may be a solution for reducing dust concentrations in road sites, far more effective than street sweeping activities.

Investigation of the behavior of potentially hazardous trace elements in Kentucky coals and combustion byproducts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robertson, J.D.; Blanchard, L.J.; Srikantapura, S.

1996-12-31

The minor- and trace-element content of coal is of great interest because of the potentially hazardous impact on human health and the environment resulting from their release during coal combustion. Of the one billion tons of coal mined annually in the United States, 85-90% is consumed by coal-fired power plants. Potentially toxic elements present at concentrations as low as a few egg can be released in large quantities from combustion of this magnitude. Of special concern are those trace elements that occur naturally in coal which have been designated as potential hazardous air pollutants (HAPs) in the 1990 Amendments tomore » the Clean Air Act. The principle objective of this work was to investigate a combination of physical and chemical coal cleaning techniques to remove 90 percent of HAP trace elements at 90 percent combustibles recovery from Kentucky No. 9 coal. Samples of this coal were first subjected to physical separation by flotation in a Denver cell. The float fraction from the Denver cell was then used as feed material for hydrothermal leaching tests in which the efficacy of dilute alkali (NaOH) and acid (HNO{sub 3}) solutions at various temperatures and pressures was investigated. The combined column flotation and mild chemical cleaning strategy removed 60-80% of trace elements with greater than 85, recovery of combustibles from very finely ground (-325 mesh) coal. The elemental composition of the samples generated at each stage was determined using particle induced X-ray emission (PIXE) analysis. PIXE is a rapid, instrumental technique that, in principle, is capable of analyzing all elements from sodium through uranium with sensitivities as low as 1 {mu}g/g.« less

Identification of deposit types of natural corundum by PIXE

NASA Astrophysics Data System (ADS)

Chulapakorn, T.; Intarasiri, S.; Bootkul, D.; Singkarat, S.

2014-07-01

Natural corundum, one of the most important exports of Thailand, is a rare, durable and valuable gemstone. The value of these precious stones is determined by their visual appearances, including brilliance, color, fire (light dispersion) and luster. Corundum is an allochromatic mineral whose trace element concentration depends on the origin and has influence on price setting. This work attempts to use an alternative method to identify the geological deposits of rubies and sapphires found in the Thai market which came from various countries, e.g., Africa, Cambodia, Myanmar, Sri Lanka, Thailand and USA. Interrelations between most important major trace elements are the main results of this work. Quantitative analysis of trace elements were performed by particle-induced X-ray emission (PIXE) technique, using 2-MeV proton beam generated and accelerated by the 1.7 MV tandem accelerator at Chiang Mai University. The trace elements of interest are Ti, Cr, Fe and Ga. We have found that the relationships between the ratios of trace element concentration can be used to classify the deposit type. Moreover, this method shows a clear separation between two main types of geological deposits, basaltic and metamorphic deposits, which further helps in determining the gemstone origin. For example, the gemstones from Cambodia, Thailand and the USA can be classified as the basaltic deposits with their high concentration in Fe but low in Ti, while the gemstones from Africa, Myanmar and Sri Lanka are metamorphic deposits because they have low Fe but high Ti concentrations. Both deposits required plots of pairs of trace elements and their ratios in population field appearance in order to distinguish their origins. The advantageous of these methods appear to be a new and a sustainable procedure for determining gemstone origins.

Involvement of Alpha-PAK-Interacting Exchange Factor in the PAK1–c-Jun NH2-Terminal Kinase 1 Activation and Apoptosis Induced by Benzo[a]pyrene

PubMed Central

Yoshii, Shigeto; Tanaka, Masamitsu; Otsuki, Yoshiro; Fujiyama, Toshiharu; Kataoka, Hideki; Arai, Hajime; Hanai, Hiroyuki; Sugimura, Haruhiko

2001-01-01

Benzo[a]pyrene [B(a)P], a potent procarcinogen found in combustion products such as diesel exhaust and cigarette smoke, has been recently shown to activate the c-Jun NH2-terminal kinase 1 (JNK1) and induce caspase-3-mediated apoptosis in Hepa1c1c7 cells. However, the molecules of the signaling pathway that control the mitogen-activated protein kinase cascades induced by B(a)P and the interaction between those and apoptosis by B(a)P have not been well defined. We report here that B(a)P promoted Cdc42/Rac1, p21-activated kinase 1 (PAK1), and JNK1 activities in 293T and HeLa cells. Moreover, alpha-PAK-interacting exchange factor (α PIX) mRNA and its protein expression were upregulated by B(a)P. While overexpression of an active mutant of α PIX (ΔCH) facilitated B(a)P-induced activation of Cdc42/Rac1, PAK1, and JNK1, overexpression of mutated αPIX (L383R, L384S), which lacks guanine nucleotide exchange factor activity, SH3 domain-deleted αPIX (Δ SH3), which lacks the ability to bind PAK, kinase-negative PAK1 (K299R), and kinase-negative SEK1 (K220A, K224L) inhibited B(a)P-triggered JNK1 activation. Interestingly, overexpression of αPIX (Δ CH) and a catalytically active mutant PAK1 (T423E) accelerated B(a)P-induced apoptosis in HeLa cells, whereas αPIX (Δ SH3), PAK1 (K299R), and SEK 1 (K220A, K224L) inhibited B(a)P-initiated apoptosis. Finally, a preferential caspase inhibitor, Z-Asp-CH2-DCB, strongly blocked the αPIX (Δ CH)-enhanced apoptosis in cells treated with B(a)P but did not block PAK1/JNK1 activation. Taken together, these results indicate that αPIX plays a crucial role in B(a)P-induced apoptosis through activation of the JNK1 pathway kinases. PMID:11564864

Optimization of PIXE-sensitivity for detection of Ti in thin human skin sections

NASA Astrophysics Data System (ADS)

Pallon, Jan; Garmer, Mats; Auzelyte, Vaida; Elfman, Mikael; Kristiansson, Per; Malmqvist, Klas; Nilsson, Christer; Shariff, Asad; Wegdén, Marie

2005-04-01

Modern sunscreens contain particles like TiO2 having sizes of 25-70 nm and acting as a reflecting substance. For cosmetic reasons the particle size is minimized. Questions have been raised to what degree these nano particles penetrate the skin barrier, and how they do affect the human. The EU funded project "Quality of skin as a barrier to ultra-fine particles" - NANODERM has started with the purpose to evaluate the possible risks of TiO2 penetration into vital skin layers. The purpose of the work presented here was to find the optimal conditions for micro-PIXE analysis of Ti in thin skin sections. In the skin region where Ti is expected to be found, the naturally occurring major elements phosphorus, chlorine, sulphur and potassium have steep gradients and thus influence the X-ray background in a non-predictable manner. Based on experimental studies of Ti-exposed human skin sections using proton energies ranging from 1.8-2.55 MeV, the corresponding PIXE detection limits for Ti were calculated. The energy that was found to be the most favourable, 1.9 MeV, was then selected for future studies.

Environmental impact of fertilizer industries evaluated by PIXE

NASA Astrophysics Data System (ADS)

Martín, J. E.; Bolívar, J. P.; Respaldiza, M. A.; García-Tenorio, R.; da Silva, M. F.

1995-12-01

In this paper the environmental impact of several phosphogypsum piles sited in the southwest of Spain is studied using multielemental analysis by PIXE of 12 salt marsh and soil samples collected in their surroundings. The piles are used to store the main by-product formed in the production of phosphoric acid and phosphate fertilizers. The samples collected were bombarded with 2.5 MeV protons from the 3 MV Van de Graaff accelerator in the ITN at Sacavèm (Portugal), and 20 elements from Al to Pb were detected. The results obtained reinforce previous radioanalytical determinations concerning the significant radioactive contamination pathways (leaching or/and dissolution of elements by water from the piles) and the negligible pathways (atmospheric and direct aquatic transport).

Design and Development of a Virtual Facility Tour Using iPIX(TM) Technology

NASA Technical Reports Server (NTRS)

Farley, Douglas L.

2002-01-01

The capabilities of the iPIX virtual tour software, in conjunction with a web-based interface create a unique and valuable system that provides users with an efficient virtual capability to tour facilities while being able to acquire the necessary technical content is demonstrated. A users guide to the Mechanics and Durability Branch's virtual tour is presented. The guide provides the user with instruction on operating both scripted and unscripted tours as well as a discussion of the tours for Buildings 1148, 1205 and 1256 and NASA Langley Research Center. Furthermore, an indepth discussion has been presented on how to develop a virtual tour using the iPIX software interface with conventional html and JavaScript. The main aspects for discussion are on network and computing issues associated with using this capability. A discussion of how to take the iPIX pictures, manipulate them and bond them together to form hemispherical images is also presented. Linking of images with additional multimedia content is discussed. Finally, a method to integrate the iPIX software with conventional HTML and JavaScript to facilitate linking with multi-media is presented.

Corrosion of 15th and early 16th century stained glass from the monastery of Batalha studied with external ion beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vilarigues, M., E-mail: mgv@fct.unl.pt; Redol, P.; Monastery of Batalha, P-2440

2011-02-15

This paper reports the study of corrosion in two stained glass panels from the south aisle of Sta. Maria da Vitoria monastery, at Batalha (Portugal), one depicting the Last Supper (dated from 1508), and the other one showing a saint (c. 1450). These panels exhibit extensive corrosion with darkening phenomena that are an impediment to their correct visualization, a source of major concern both to conservators and curators. By using external micro-beam Particle Induced X-ray Emission (PIXE) and Particle Induced Gamma Emission (PIGE) spectrometry, the elemental compositions of large fragments were obtained, enabling the selection of representative corroded areas, frommore » which elemental distribution maps were produced by scanning. Calcium and potassium rich structures were found - at the surface and inside cavities in the glass - that were identified as oxalates and carbonates, by Raman microscopy and micro-FTIR. The dark spots present in the glass surfaces were found to be Zn and Pb rich. These findings indicate that the corrosion observed was due not only to reactions with atmospheric water and CO{sub 2} but also with the oxalic acid secreted by micro-organisms. Furthermore, it did not result from reactions with atmospheric SO{sub 2} or acid rain. The information obtained is relevant for a better understanding of the corrosion processes and products formed on the surface of these panels and therefore for the proper planning of much needed adequate conservation-restoration actions and appropriate display conditions. - Research Highlights: {yields} Corrosion and darkening of stained glasses is of concern to conservators and curators. {yields} A multi-technique approach is of relevance to study stained glass corrosion. {yields} External beam PIXE-PIGE provide valuable insight on stained glass corrosion.« less

Aerosol deposition in the human respiratory tract

NASA Astrophysics Data System (ADS)

Winchester, John W.; Jones, Donald L.; Mu-tian, Bi

1984-04-01

Rising sulfur dioxide emissions from increased coal combustion present risks, not only of acid rain, but also to health by inhalation of the SO 2 and acid to the lung. We are investigating human inhalation of ppm SO 2 concentrations mixed with aerosol of submicrometer aqueous salt droplets to determine the effects on lung function and body chemistry. Unlike some investigators, we emphasize ammonium sulfate and trace element aerosol composition which simulates ambient air; aerosol pH, relative humidity, and temperature control to reveal gas-particle reaction mechanisms; and dose estimates from length of exposure, SO 2 concentration, and a direct measurement of respiratory deposition of aerosol as a function of particle size by cascade impactor sampling and elemental analysis by PIXE. Exposures, at rest or during exercise, are in a walk-in chamber at body temperature and high humidity to simulate Florida's summer climate. Lung function measurement by spirometry is carried out immediately after exposure. The results are significant in relating air quality to athletic performance and to public health in the southeastern United States.

Proton-induces and x-ray induced fluorescence analysis of scoliotic tissue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Panessa-Warren, B J; Kraner, H W; Jones, K W

1980-02-01

Adolescent idiopathic scoliosis is characterized by a curvature or assymetry of the spine which may become progressively more severe, with clinical symptoms appearing just prior to, or during, puberty. The incidence for scoliosis in the age group from 12 to 14 years of age has been reported as high as 8 to 10%, with more than 80% of the cases occurring in females. Although pathologic changes exist in muscles from both sides of the spinal curvature, and no statistically significant side differences have been reported, morphologic changes suggest that the concanve side is the most affected. This paper reports ourmore » preliminary data on the elemental composition of individual muscle fibers derived from convex, concave and gluteal scoliotic muscle, and erythrocytes from scoliotic and normal patients, analyzed by proton induced x-ray emission (PIXE) and x-ray fluorescence spectroscopy (XRF). A new type of specimen holder was designed for this study which offers low x-ray background, minimal absorption and maintenance of a moist environment around the specimen.« less

Applications of nuclear analytical techniques to environmental studies

NASA Astrophysics Data System (ADS)

Freitas, M. C.; Pacheco, A. M. G.; Marques, A. P.; Barros, L. I. C.; Reis, M. A.

2001-07-01

A few examples of application of nuclear-analytical techniques to biological monitors—natives and transplants—are given herein. Parmelia sulcata Taylor transplants were set up in a heavily industrialized area of Portugal—the Setúbal peninsula, about 50 km south of Lisbon—where indigenous lichens are rare. The whole area was 10×15 km around an oil-fired power station, and a 2.5×2.5 km grid was used. In north-western Portugal, native thalli of the same epiphytes (Parmelia spp., mostly Parmelia sulcata Taylor) and bark from olive trees (Olea europaea) were sampled across an area of 50×50 km, using a 10×10 km grid. This area is densely populated and features a blend of rural, urban-industrial and coastal environments, together with the country's second-largest metro area (Porto). All biomonitors have been analyzed by INAA and PIXE. Results were put through nonparametric tests and factor analysis for trend significance and emission sources, respectively.

PIXE analysis of sand and soil from Ulaanbaatar and Karakurum, Mongolia

NASA Astrophysics Data System (ADS)

Markwitz, A.; Barry, B.; Shagjjamba, D.

2008-09-01

Twenty-one sand and soil samples were collected at the surface from 22 to 25 June 2007 at sampling sites from Ulaanbaatar to Karakurum, Mongolia. The sand samples were collected from constantly changing sand dunes which may still contain salt from prehistoric oceans. The dry sand and soil samples were processed for PIXE and PIGE analyses. A clear division between soils and sand become apparent in the silicon results. Concentrations of all bulk elements in human habitation samples and of Si, Al, K and Fe in dry lake/flood plain samples are similar to those in the soils and sands. Among elements which could be regarded as being at trace concentrations the average S concentration in the soils is 0.9 g kg-1 whereas it is not detected in the sand samples. Zinc and Cu concentrations are both higher in the soils than the sands and are strongly correlated. A surprising presence of uranium at a concentration of 350 mg kg-1 was detected in the PIXE measurement on one of the dry lake samples. Gamma spectrometry confirmed the presence of U in this sample and also at a lower level in a sample from the lake shore, but in none of the other samples. Further, the gamma spectrometry showed that 238U decay products were present only at a level corresponding to about 3 mg kg-1 U for a system in radioactive equilibrium, a figure which is typical for U in the earth's crust. Disequilibria between 238U and its decay products occur naturally but such a high degree of separation at high concentration would be unique if confirmed. PIXE and PIGE measurements of these samples highlight the difficulty in correlating trace element measurements with occurrence of indicators of sea salt in air particulate samples.

Study of the effect of common infusions on glass ionomers using the PIXE and RBS techniques

NASA Astrophysics Data System (ADS)

Verón, María Gisela; Pérez, Pablo Daniel; Suárez, Sergio Gabriel; Prado, Miguel Oscar

2017-12-01

The effect of four commonly consumed beverages as mineral water, coffee, tea and mate tea on the elemental composition of a commercial glass ionomer was studied using Particle Induced X-ray Emission (PIXE) and Rutherford backscattering (RBS) techniques. We found that after immersion in acidic media, some elements as Al, Si and Na are lost from the glass-ionomer whereas others heavier, as K, Ca and La, increase their concentration at the surface. Although the concentration profiles of Al and Si are different in different media, in all of them the Al:Si ratio was close to unity and remained constant for different periods of immersion in all media. The incorporation of K, Mg and Fe to the surface is found for common infusions while for mineral water the glass-ionomer mainly loses F and Na.The RBS technique showed that immersion in different media produced a modification of the density of the glass ionomer surface layer due to the increment of the concentration of heavier elements at the surface. The thickness of the modified surface layer extends up to 3 μm when the immersion time is seven days and more than 6 μm after 33 days of immersion.

Characterization of human kidney stones using micro-PIXE and RBS: a comparative study between two different populations.

PubMed

Pineda-Vargas, C A; Eisa, M E M; Rodgers, A L

2009-03-01

The micro-PIXE and RBS techniques are used to investigate the matrix as well as the trace elemental composition of calcium-rich human tissues on a microscopic scale. This paper deals with the spatial distribution of trace metals in hard human tissues such as kidney stone concretions, undertaken at the nuclear microprobe (NMP) facility. Relevant information about ion beam techniques used for material characterization will be discussed. Mapping correlation between different trace metals to extract information related to micro-regions composition will be illustrated with an application using proton energies of 1.5 and 3.0 MeV and applied to a comparative study for human kidney stone concretions nucleation region analysis from two different population groups (Sudan and South Africa).

Development of a new in-air micro-PIXE set-up with in-vacuum charge measurements in Atomki

NASA Astrophysics Data System (ADS)

Török, Zs.; Huszánk, R.; Csedreki, L.; Dani, J.; Szoboszlai, Z.; Kertész, Zs.

2015-11-01

A new external microbeam set-up has recently been installed as the extension of the existing microprobe system at the Laboratory of Ion Beam Applications of Atomki, Debrecen, Hungary. The external beam set-up, based on the system of Oxford Microbeams (OM), is equipped with two X-ray detectors for PIXE analysis, a digital microscope, two alignment lasers and a precision XYZ stage for easy and reproducible positioning of the sample. Exit windows with different thicknesses and of different materials can be used according to the actual demands, currently silicon-nitride (Si3N4) film with 200 nm thickness is employed in our laboratory. The first application was demonstrated in the field of archaeometry, on Bronze Age hoards from Hungary.

Differential PIXE for investigating the layer structure of paintings

NASA Astrophysics Data System (ADS)

Mandò, P. A.; Fedi, M. E.; Grassi, N.; Migliori, A.

2005-09-01

This paper reports an example of how the differential PIXE technique can be successfully applied to the investigation of wood or canvas paintings. The work analysed is a famous wood painting by Leonardo da Vinci, the "Madonna dei fusi" (ex-Reford version, 1501), chosen for a pilot study in a wide international project aimed at analysing Leonardo's works of art by means of non-destructive techniques. While illustrating the results obtained concerning the identification of pigments and the discrimination of the stratigraphy of layers, the merits and limits of differential PIXE in general are pointed out.

Homogeneity of CdZnTe detectors

NASA Astrophysics Data System (ADS)

Hermon, H.; Schieber, M.; James, R. B.; Lund, J.; Antolak, A. J.; Morse, D. H.; Kolesnikov, N. N. P.; Ivanov, Y. N.; Goorsky, M. S.; Yoon, H.; Toney, J.; Schlesinger, T. E.

1998-02-01

We describe the current state of nuclear radiation detectors produced from single crystals of Cd 1- xZn xTe(CZT), with 0.04 < x < 0.4, grown by the vertical high pressure Bridgman (VHPB) method. The crystals investigated were grown commercially both in the USA and at the Institute of Solid State Physics, Chernogolska, Russia. The CZT was evaluated by Sandia National Laboratories and the UCLA and CMU groups using proton-induced X-ray emission (PIXE), X-ray diffraction (XRD), photoluminescence (PL), infrared (IR) transmission microscopy, leakage current measurements and response to nuclear radiation. We discuss the homogeneity of the various CZT crystals based on the results from these measurement techniques.

Reaction of metals in lower earth orbit during Space Shuttle flight 41-G

NASA Technical Reports Server (NTRS)

Fromhold, A. T., Jr.; Daneshvar, K.; Whitaker, A. F.; Little, S. A.

1985-01-01

The effects of ambient space environment on metals were studied by exposing specimens of Cu, Ag, Au, Ni, Cr, Al, Pt, and Pd on flight 41-G (STS-17). Data obtained by ellipsometry (ELL), Rutherford backscattering (RBS), and proton-induced X-ray emission (PIXE) before and after flight are summarized. Although the effects of space environment were most pronounced for silver, there were significant changes in the surface properties of the majority of the other metals. The surface optical constants proved to be the most sensitive measure of surface changes. These changes are attributed to the interaction of the metals with atomic oxygen.

An extracellular-matrix-specific GEF-GAP interaction regulates Rho GTPase crosstalk for 3D collagen migration.

PubMed

Kutys, Matthew L; Yamada, Kenneth M

2014-09-01

Rho-family GTPases govern distinct types of cell migration on different extracellular matrix proteins in tissue culture or three-dimensional (3D) matrices. We searched for mechanisms selectively regulating 3D cell migration in different matrix environments and discovered a form of Cdc42-RhoA crosstalk governing cell migration through a specific pair of GTPase activator and inhibitor molecules. We first identified βPix, a guanine nucleotide exchange factor (GEF), as a specific regulator of migration in 3D collagen using an affinity-precipitation-based GEF screen. Knockdown of βPix specifically blocks cell migration in fibrillar collagen microenvironments, leading to hyperactive cellular protrusion accompanied by increased collagen matrix contraction. Live FRET imaging and RNAi knockdown linked this βPix knockdown phenotype to loss of polarized Cdc42 but not Rac1 activity, accompanied by enhanced, de-localized RhoA activity. Mechanistically, collagen phospho-regulates βPix, leading to its association with srGAP1, a GTPase-activating protein (GAP), needed to suppress RhoA activity. Our results reveal a matrix-specific pathway controlling migration involving a GEF-GAP interaction of βPix with srGAP1 that is critical for maintaining suppressive crosstalk between Cdc42 and RhoA during 3D collagen migration.

Expert Images for All Audiences: The AstroPix Archive

NASA Astrophysics Data System (ADS)

Hurt, Robert; Llamas, Jacob; Wyatt, Ryan Jason; Christensen, Lars

2018-01-01

The AstroPix project provides one-stop-shopping for an extensive collection of the finest astronomical imagery, sourced from some of the world’s most prominent observatories. The archive is made possible by a grassroots effort to tag publicly-released imagery using the Astronomical Visualization Metadata (AVM) standard, which captures rich contextual information for each image. While the site has been in development for many years, it is now supported under NASA’s Universe of Learning collaboration, and AstroPix has been updated and deployed to cloud services. The AVM tags provide many unique features including spectral color assignments, sky context (using AAS WorldWide Telescope APIs), and direct links to the original source material on the web. The 7,000+ assets currently include imagery provided by Chandra, ESO, GALEX, Herschel, Hubble, NuSTAR, Spitzer, and WISE. The assets are also provided for use in the planetarium community by supporting the Data2Dome (D2D) initiative. AstroPix imagery is designed to be used in a variety of unique ways that benefit formal and informal education as well as astronomers and the general public. Observatories can add their own image archives to AstroPix by tagging their assets and providing a simple XML feed, increasing the value of their data to the community at large.

H+, O2+, O3+ and high resolution PIXE spectra of Yb2O3

NASA Astrophysics Data System (ADS)

Chaves, P. C.; Reis, M. A.

2017-11-01

The number of X-ray spectrometry systems having energy resolution of the order of 10 eV, or less, has increasing recently, included already energy dispersive systems (EDS). Access to previous unseen spectra details and enhanced information including speciation, becomes more common and available. Analysis of high resolution EDS PIXE spectra is, nevertheless a complex task due to the need to carefully account for contributions from minor and satellite transitions. In this work, a pure Yb2O3 sample was irradiated at the HRHE-PIXE setup of C2TN, and simultaneous CdTe and X-ray Microcalorimeter Spectrometer (XMS) spectra were collected. The L-shell spectrum of Yb emitted during irradiations using H+ , O2+ and O3+ ions in the energy range from 1.0 to 6.5 MeV was studied. Measured L X-ray spectra were analysed taking into account the effects of the multiple ionization in the L and M shells. All spectra were analysed using the DT2 code, which allows to include in the fitting model diagram lines as well as multi-ionization satellites and any other contributions. In this communication we present the results and discuss details and problems related to the transition energies, intensity, line width data, and multiple ionization satellites.

Paintings on copper by the Flemish artist Frans Francken II: PIXE characterization by external microbeam

NASA Astrophysics Data System (ADS)

Corregidor, V.; Oliveira, A. R.; Rodrigues, P. A.; Alves, L. C.

2015-04-01

Resorting to an external proton microbeam, PIXE analyses of three oil paintings on copper support dated from the XVII century and attributed to the Flemish artist Frans Francken II, were undertaken. The present work aims to contribute to the compositional study of the painting materials employed by XVII century artists that exploited copper as a support for oil painting, and specifically the materials used by Francken's workshop, particularly copper plates. Because of the low thickness of the pictorial layers of this type of paintings and its non-destructive character, PIXE is the ideal technique to study the elemental composition of the paintings. Several spots in each painting were chosen for analysis in order to cover almost all the pigments used in the colour palette. Lead and calcium were detected in practically every analysed regions, probably related to the presence of lead white and chalk, usually used as ground layer on copper paintings. Small quantities of gold were also detected, which is present in many of this artist's works to embellish some details of the representations. Also this work reports the first application of the external proton microbeam set-up available at CTN/IST in Portugal for the characterization of oil paintings.

PIXE analysis of Italian ink drawings of the XVI century

NASA Astrophysics Data System (ADS)

Zucchiatti, A.; Climent-Font, A.; Enguita, O.; Fernandez-Jimenez, M. T.; Finaldi, G.; Garrido, C.; Matillas, J. M.

2005-10-01

The composition of inks in a group of 24 drawings of ten XVI century Italian painters, has been determined by PIXE at the external micro-beam line of the Centro de Micro Análisis de Materiales of the Universidad Autónoma de Madrid. Ink elemental thicknesses have been determined by comparison with a set of certified thin standards. A comprehensive comparison of inks has also been performed by renormalisation of spectra and definition of an ink-to-ink distance. The elemental compositions and the ink-to-ink distances give consistent results that are generally in line with the appearance of the drawings and add relevant instrumental information to the stylistic observation, revealing for example the presence of retouches and additions in different parts of a drawing. Cluster analysis performed on a subgroup of 13 artefacts from the Genoese painter Luca Cambiaso and his school has revealed a partition that separates neatly the work of the master from that of his followers.

GridPix detectors: Production and beam test results

NASA Astrophysics Data System (ADS)

Koppert, W. J. C.; van Bakel, N.; Bilevych, Y.; Colas, P.; Desch, K.; Fransen, M.; van der Graaf, H.; Hartjes, F.; Hessey, N. P.; Kaminski, J.; Schmitz, J.; Schön, R.; Zappon, F.

2013-12-01

The innovative GridPix detector is a Time Projection Chamber (TPC) that is read out with a Timepix-1 pixel chip. By using wafer post-processing techniques an aluminium grid is placed on top of the chip. When operated, the electric field between the grid and the chip is sufficient to create electron induced avalanches which are detected by the pixels. The time-to-digital converter (TDC) records the drift time enabling the reconstruction of high precision 3D track segments. Recently GridPixes were produced on full wafer scale, to meet the demand for more reliable and cheaper devices in large quantities. In a recent beam test the contribution of both diffusion and time walk to the spatial and angular resolutions of a GridPix detector with a 1.2 mm drift gap are studied in detail. In addition long term tests show that in a significant fraction of the chips the protection layer successfully quenches discharges, preventing harm to the chip.

BetaPIX and GIT1 regulate HGF-induced lamellipodia formation and WAVE2 transport.

PubMed

Morimura, Shigeru; Suzuki, Katsuo; Takahashi, Kazuhide

2009-05-08

Formation of lamellipodia is the first step during cell migration, and involves actin reassembly at the leading edge of migrating cells through the membrane transport of WAVE2. However, the factors that regulate WAVE2 transport to the cell periphery for initiating lamellipodia formation have not been elucidated. We report here that in human breast cancer MDA-MB-231 cells, the hepatocyte growth factor (HGF) induced the association between the constitutive complex of betaPIX and GIT1 with WAVE2, which was concomitant with the induction of lamellipodia formation and WAVE2 transport. Although depletion of betaPIX by RNA interference abrogated the HGF-induced WAVE2 transport and lamellipodia formation, GIT1 depletion caused HGF-independent WAVE2 transport and lamellipodia formation. Collectively, we suggest that betaPIX releases cells from the GIT1-mediated suppression of HGF-independent responses and recruits GIT1 to WAVE2, thereby facilitating HGF-induced WAVE2 transport and lamellipodia formation.

Antibody Fab display and selection through fusion to the pIX coat protein of filamentous phage.

PubMed

Tornetta, Mark; Baker, Scott; Whitaker, Brian; Lu, Jin; Chen, Qiang; Pisors, Eileen; Shi, Lei; Luo, Jinquan; Sweet, Raymond; Tsui, Ping

2010-08-31

Fab antibody display on filamentous phage is widely applied to de novo antibody discovery and engineering. Here we describe a phagemid system for the efficient display and affinity selection of Fabs through linkage to the minor coat protein pIX. Display was successful by fusion of either Fd or Lc through a short linker to the amino terminus of pIX and co-expression of the counter Lc or Fd as a secreted, soluble fragment. Assembly of functional Fab was confirmed by demonstration of antigen-specific binding using antibodies of known specificity. Phage displaying a Fab specific for RSV-F protein with Fd linked to pIX showed efficient, antigen-specific enrichment when mixed with phage displaying a different specificity. The functionality of this system for antibody engineering was evaluated in an optimization study. A RSV-F protein specific antibody with an affinity of about 2nM was randomized at 4 positions in light chain CDR1. Three rounds of selection with decreasing antigen concentration yielded Fabs with an affinity improvement up to 70-fold and showed a general correlation between enrichment frequency and affinity. We conclude that the pIX coat protein complements other display systems in filamentous phage as an efficient vehicle for low copy display and selection of Fab proteins. 2010 Elsevier B.V. All rights reserved.

Computer Graphics: KidPix, the MacIntosh, and Students with Cognitive Disorders.

ERIC Educational Resources Information Center

Olson, Cindy

This teacher's guide provides an overview of KidPix software and contains adaptive applications of the software for Cognitively Disabled-Borderline (CDB) students. Ten lesson plans are given, including: (1) "USing Rubber Stamps/Rubber Stamp Editor"; (2) "Portrait"; (3) "Create a Pattern"; (4) "Garden Mural";…

Presentation Software and the Single Computer.

ERIC Educational Resources Information Center

Brown, Cindy A.

1998-01-01

Shows how the "Kid Pix" software and a single multimedia computer can aid classroom instruction for kindergarten through second grade. Topics include using the computer as a learning center for small groups of students; making a "Kid Pix" slide show; using it as an electronic chalkboard; and creating curriculum-related…

The non-destructive identification of early Chinese porcelain by PIXE

NASA Astrophysics Data System (ADS)

Cheng, H. S.; Zhang, Z. Q.; Zhang, B.; Yang, F. J.

2004-06-01

PIXE is used for the non-destructive differentiation of early precious Chinese blue and white porcelain made in Yuan (AD 1206-1368), Ming (AD 1368-1644) Dynasty in Jingdezhen from imitations. Also, ancient celadon made in Song Dynasty (AD 960-1279) is identified by measuring the trace elements contained in the glazes.

Effects of 1,1-Dimethylpiperidinium Chloride on the Pests and Allelochemicals of Cotton and Pecan.

Treesearch

P. A. Hedin; J. N. Jenkins; J. C. McCarty; J. E. Mulrooney; W. L. Parrott; A. Borazjani; C. H. Graves; T. H. Filer

1984-01-01

The growth regulator, PIX (mepiquat chloride - 1,1-dimethyl-piperdinium chloride), when applied to cotton (Gossypium hirsutum L.) and pecan (Carya illinoensis Koch), caused internode shortening. PIX did not elicit an increase in resistance in cotton to the tobacco budworm (Heliothis virescens (Fab.)], or in pecan...

Design and characterization of the ePix10k: a high dynamic range integrating pixel ASIC for LCLS detectors

NASA Astrophysics Data System (ADS)

Caragiulo, P.; Dragone, A.; Markovic, B.; Herbst, R.; Nishimura, K.; Reese, B.; Herrmann, S.; Hart, P.; Blaj, G.; Segal, J.; Tomada, A.; Hasi, J.; Carini, G.; Kenney, C.; Haller, G.

2015-05-01

ePix10k is a variant of a novel class of integrating pixel ASICs architectures optimized for the processing of signals in second generation LINAC Coherent Light Source (LCLS) X-Ray cameras. The ASIC is optimized for high dynamic range application requiring high spatial resolution and fast frame rates. ePix ASICs are based on a common platform composed of a random access analog matrix of pixel with global shutter, fast parallel column readout, and dedicated sigma-delta analog to digital converters per column. The ePix10k variant has 100um×100um pixels arranged in a 176×192 matrix, a resolution of 140e- r.m.s. and a signal range of 3.5pC (10k photons at 8keV). In its final version it will be able to sustain a frame rate of 2kHz. A first prototype has been fabricated and characterized. Performance in terms of noise, linearity, uniformity, cross-talk, together with preliminary measurements with bump bonded sensors are reported here.

Monitoring trace elements generated by automobiles: air pollutants with possible health impacts.

PubMed

Anwar, Khaleeq; Ejaz, Sohail; Ashraf, Muhammad; Ahmad, Nisar; Javeed, Aqeel

2013-07-01

Major transformations in the environmental composition are principally attributable to the combustion of fuels by automobiles. Motorized gasoline-powered two-stroke auto-rickshaws (TSA) and compressed natural gas (CNG)-powered four-stroke auto-rickshaws (FSA) are potential source of air pollution in south Asia and produce toxic amount of particulate matter (PM) to the environment. In this study, we attempted to characterize elemental pollutants from the PM of TSA and FSA using proton-induced X-ray emission (PIXE) analysis. The observations of the existing investigation recognized significant increase in Al (P < 0.05), P (P < 0.01), and Zn (P < 0.01) from the PM samples of FSA. In addition, the concentrations of Cu, Fe, K, Mg, Na and S were also observed exceeding the recommended National Institute for Environmental Studies limits. On the contrary, increased concentration of Sr and V were observed in the PM samples from TSA. It is generally believed that FSA generates smaller amount of PM but data obtained from FSA are clearly describing that emissions from FSA comprised potentially more toxic substances than TSA. The current research is specific to metropolitan population and has evidently revealed an inconsistent burden of exposure to air pollutants engendered by FSA in urban communities, which could lead to the disruption of several biological activities and may cause severe damage to entire ecological system.

Phosphorylation of tyrosine 285 of PAK1 facilitates βPIX/GIT1 binding and adhesion turnover

PubMed Central

Hammer, Alan; Oladimeji, Peter; De Las Casas, Luis E.; Diakonova, Maria

2015-01-01

The p21-activated serine-threonine kinase (PAK1) regulates cell motility and adhesion. We have previously shown that the prolactin (PRL)-activated tyrosine kinase JAK2 phosphorylates PAK1 in vivo and in vitro and identified tyrosines 153, 201, and 285 in PAK1 as sites of JAK2 tyrosyl phosphorylation. Here, we further investigate the role of the tyrosyl phosphorylated PAK1 (pTyr-PAK1) in regulation of cell adhesion. We use human breast cancer T47D cell lines that stably overexpress PAK1 wild type or PAK1 Y3F mutant in which these 3 JAK2 phosphorylation sites were mutated to phenylalanine. We demonstrate that PRL/JAK2-dependent phosphorylation of these tyrosines promotes a motile phenotype in the cells upon adhesion, participates in regulation of cell adhesion on collagen IV, and is required for maximal PAK1 kinase activity. Down-regulation of PAK1 abolishes the effect of PAK1 on cell adhesion. We show that the tyrosyl phosphorylation of PAK1 promotes PAK1 binding to β-PAK1-interacting guanine-nucleotide exchange factor (βPIX) and G protein-coupled receptor kinase-interacting target 1 (GIT1), phosphorylation of paxillin on Ser273, and formation and distribution of adhesion complexes. Using phosphospecific antibodies (Abs) directed to single phosphorylated tyrosines on PAK1, we identified Tyr285 as a site of PRL-dependent phosphorylation of PAK1 by JAK2. Furthermore, using PAK1 Y285F mutant, we provide evidence for a role of pTyr285 in cell adhesion, enhanced βPIX/GIT1 binding, and adhesion turnover. Our immunohistochemistry analysis demonstrates that pTyr285- PAK1 may modulate PAK1 signaling during tumor progression.—Hammer, A., Oladimeji, P., De La Casas, L. E., Diakonova, M. Phosphorylation of tyrosine 285 of PAK1 facilitates bPIX/GIT1 binding and adhesion turnover. PMID:25466889

Regional Stratigraphy from Stereo Imaging near the Hypanis Fan Deposit: Marking the Extent of the Largest Delta on Mars?

NASA Astrophysics Data System (ADS)

Adler, J.; Harrison, T. N.; Bell, J. F., III; Mayer, D. P.

2017-12-01

The layered fan-shaped sedimentary deposit at the terminus of Hypanis Valles has been classified by some as an ancient delta marking the presence of a sea in Chryse Planitia, Mars. The deposit's age is estimated to be 3.6 Ga based on crater counts in the upstream catchment. We further our research on the Hypanis deposit and its relative age by analyzing digital terrain models and high-resolution orbital images of two key study areas: Lederberg crater rim and the distal island deposits. We constructed a 2 m/pix digital terrain model from our requested HiRISE stereo images (0.5 m/pix) of the Lederberg rim northwest of Hypanis, as well as a 24 m/pix digital terrain model from CTX stereo images (6 m/pix) of the island structures northeast of Hypanis. Both terrain models were controlled to MOLA shot data. We added these elevation models to a regional elevation mosaic in order to assess stratigraphy. We found that the Lederberg crater rim has polygonally fractured units, consistent with those in the plains near Hypanis, as well as an example of a distinct mildly sinuous ridge with smooth cones along its profile. We hypothesize that the formation of rounded cones in this region of Xanthe Terra near Hypanis is related to the presence of wrinkle ridges and degraded crater rims. Furthermore, we investigate whether these cones are the youngest geologic formations in the region, postdating the aqueous periods in which the delta and hydrovolcanic cones were formed. We also analyzed the elevation profiles of potential deltaic distal island deposits, and found that some islands are likely part of the main lobe of Hypanis, while others more closely match the chaos units to the east. From our analysis, it is unlikely that the large northern island was once part of the Hypanis deposit. Rather, a larger laterally continuous unit likely once draped the region post-Hypanis formation and has subsequently been eroded.

Quantitative elemental analysis of an industrial mineral talc, using accelerator-based analytical technique

NASA Astrophysics Data System (ADS)

Olabanji, S. O.; Ige, A. O.; Mazzoli, C.; Ceccato, D.; Ajayi, E. O. B.; De Poli, M.; Moschini, G.

2005-10-01

Accelerator-based technique of PIXE was employed for the determination of the elemental concentration of an industrial mineral, talc. Talc is a very versatile mineral in industries with several applications. Due to this, there is a need to know its constituents to ensure that the workers are not exposed to health risks. Besides, microscopic tests on some talc samples in Nigeria confirm that they fall within the BP British Pharmacopoeia standard for tablet formation. However, for these samples to become a local source of raw material for pharmaceutical grade talc, the precise elemental compositions should be established which is the focus of this work. Proton beam produced by the 2.5 MV AN 2000 Van de Graaff accelerator at INFN, LNL, Legnaro, Padova, Italy was used for the PIXE measurements. The results which show the concentration of different elements in the talc samples, their health implications and metabolic roles are presented and discussed.

Volatility in the lunar crust: Trace element analyses of lunar minerals by PIXE proton microprobe

NASA Technical Reports Server (NTRS)

Norman, M. D.; Griffin, W. L.; Ryan, C. G.

1993-01-01

In situ determination of mineral compositions using microbeam techniques can characterize magma compositions through mineral-melt partitioning, and be used to investigate fine-grained or rare phases which cannot be extracted for analysis. Abundances of Fe, Mn, Sr, Ga, Zr, Y, Nb, Zn, Cu, Ni, Se, and Sb were determined for various mineral phases in a small number of lunar highlands rocks using the PIXE proton microprobe. Sr/Ga ratios of plagioclase and Mn/Zn ratios of mafic silicates show that the ferroan anorthosites and Mg-suite cumulates are depleted in volatile lithophile elements to about the same degree compared with chondrites and the Earth. This links the entire lunar crust to common processes or source compositions. In contrast, secondary sulfides in Descartes breccia clasts are enriched in chalcophile elements such as Cu, Zn, Ni, Se, and Sb, and represent a potential resource in the lunar highlands.

Recent applications of PIXE spectrometry in archaeology II. Characterization of Chinese pottery exported to the Islamic world

NASA Astrophysics Data System (ADS)

Fleming, S. J.; Swann, C. P.

1992-02-01

The early 9th century A.D. trade links between China's Tang dynasty and the Western world, by land along the caravan routes of the Silk Road and by sea via India and the Gulf, encouraged a taste for many kinds of Chinese ceramics among the affluent societies of the Islamic empire. Using PIXE analysis to determine the primary composition and minor element patterns of the clay fabrics of a wide range of pottery recovered from the Islamic city of Siraf (in southern Iran), we have established clear differences between Chinese wares imported to that region and a variety of imitative wares of local origin. Parallels and contrasts are drawn between our data and those obtained by Chinese scholars in recent years for the products of various Tang kiln sites, particularly for a series of distinctive stonewares from Tongguan (Hunan province).

A microPIXE investigation of the interaction of cells of Schizosaccharomyces pombe with the culture medium

NASA Astrophysics Data System (ADS)

Rombouts, P. M. M.; Gomez-Morilla, I.; Grime, G. W.; Webb, R. P.; Cuenca, L.; Rodriguez, R.; Browton, M.; Wardell, N.; Underwood, B.; Kirkby, N. F.; Kirkby, K. J.

2007-07-01

Schizosaccharomyces pombe ( S. pombe) is a eucaryotic cell type similar to mammalian cells but much more simple. As it also executes its cell cycle rapidly it is very useful for investigating basic processes in cells. In this paper we report a feasibility study of the applicability of microPIXE to investigate the interaction between S. pombe cells and the surrounding culture medium. Cells were cultured in various growth medium prior to preparation for analysis. 1 μl drops of medium and cells were spotted onto polypropylene foils held in contact with a polished copper block previously cooled in liquid nitrogen. The samples were dehydrated by freeze-drying. Micro PIXE analysis was carried out with the IBC microbeam facility using a beam of 2.5 MeV protons focused to 1-2 μm diameter. Initially no elemental contrast was observed between the cells and the medium, but by modifying the dilution of the cell suspension, the cells could be distinguished from the surrounding medium through an increased concentration of P and reduced concentration of Cl. The distribution of Na in the medium around the cells showed evidence of the action of the Na pump. Sporulation appears to be induced in the cells by adding Cu to the growth medium and the uptake of Cu by the cells could be clearly observed. This study shows that it is possible to analyse the mass transport of elements in and out of cells In the future this will enable concentration gradients to be analysed and allow the rate of production or consumption of individual cells to be calculated. By observing these patterns for individual cells (not populations) at various known points in the cell cycle, fundamental data can be derived.

Long-Term Response and Remission with Pixantrone in Patients with Relapsed or Refractory Aggressive Non-Hodgkin Lymphoma: Post-Hoc Analysis of the Multicenter, Open-Label, Randomized PIX301 Trial.

PubMed

Pettengell, Ruth; Coiffier, Bertrand; Egorov, Anton; Singer, Jack; Sivcheva, Lilia

2018-06-01

Pixantrone is recommended in relapsed and refractory non-Hodgkin lymphoma (NHL) or heavily pretreated NHL patients. Its conditional approval in Europe was based on results from the open-label, randomized, phase 3 PIX301 study, comparing pixantrone monotherapy with physician's choice of treatment in 140 patients with relapsed or refractory aggressive NHL. This post-hoc analysis of the PIX301 study investigated possible correlations between patient characteristics and clinical response in 17 patients (24%) treated with pixantrone who achieved a complete response (CR) or an unconfirmed complete response (CRu) at study end. These patients (10 male and 7 female) had a median age of 61 (range 41-75) years, and the most common diagnoses were diffuse large B-cell lymphoma (n = 10) and transformed indolent lymphoma (n = 4). Most had received two prior lines of therapy (n = 12). There was wide variation in the time from diagnosis to study entry (219-4777 days). Among the 17 patients who achieved a CR/CRu with pixantrone, 6 had stable or progressive disease as a response to their last regimen, 7 had a partial response, and 4 had a CR/CRu. Four patients from the pixantrone group survived without progression for more than 400 days. Prior response to previous therapies did not appear to affect long-term response to pixantrone. These observations suggest that pixantrone monotherapy in patients with multiply relapsed or refractory aggressive NHL who had received at least two prior therapies can be associated with durable responses and long-term remission, and this may be unrelated to the clinical response to the last therapy.

Detection of actinides and rare earths in natural matrices with the AGLAE new, high sensitivity detection set-up

NASA Astrophysics Data System (ADS)

Zucchiatti, Alessandro; Alonso, Ursula; Lemasson, Quentin; Missana, Tiziana; Moignard, Brice; Pacheco, Claire; Pichon, Laurent; Camarena de la Mora, Sandra

2014-08-01

A series of granite samples (Grimsel and Äspö) enriched by sorption with natU (10-3 M, 10-4 M, 10-5 M in solution) and La (10-3 M, 10-4 M in solution) has been scanned by PIXE over a surface of 1920 × 1920 mm2 together with non-enriched Grimsel and Äspö granites and a glass standard. An assessment of minimum detection limits, MDL's, for several elements has been performed with the use of standard materials. Due to mapping and the high sensitivity of the new AGLAE detection system, U levels around 30 ppm can be detected from the whole PIXE spectrum (one low energy detector and four summed filtered detectors) while U reach grains, inhomogeneously distributed over the surface can be clearly identified through the multi elemental maps and analyzed separately. Even the nominally enriched samples have La levels below the MDL, probably because precipitation of the element (and not adsorption) mostly took place, and precipitates were eliminated after surface cleaning carried out before PIXE analyses. A multi detector system that implies a PIXE detection solid angle much wider than in any other similar set-up (a factor of 2-5); a higher events selectivity, given by the possibility of filtering individually up to 4 PIXE detectors; a double RBS detector, the new Ion Beam Induced Luminescence (IBIL) spectrometry and gamma spectrometry. Full mapping capability in air, assisted by a powerful event by event reconstruction software. These features allow lower Minimum Detection Limits (MDL) which are highly beneficial to the analysis of cultural heritage objects, meaning generally a reduction of irradiation time. Paintings will then be studied without any damage to the pigments that have color change tendencies which is a major drawback of the previous system. Alternatively they could allow an increase in information collected at equal time, particularly considering the detector's fast response and therefore the potential for high beam currents when sample damage can be tolerated.This kind of set-up should be advantageous for the detection of elements that are present in a geological, archaeological or artistic samples to the level of a few tens ppm. This is true in particular for the rare earths which are relevant to the provenance attribution of various classes of cultural heritage objects (clays, glasses, …) and the actinides which are relevant in very specific and highly impacting dating problems and, more generally, critical environmental elements with special reference to the radionuclide mobility in deep geological formations hosting radioactive waste [2]. Geological materials are highly heterogeneous and consequently their retention of contaminants is heterogeneous as well. In this frame, the capabilities of the AGLAE set-up would allow an improved characterization of natural heterogeneous rock, detecting the presence of the elements of interest (actinides and rare earth) at concentration levels of tens of ppm. This provides a better definition of the initial system, avoiding biased interpretation of the retention properties of the material for the analysis of possible contamination. Additionally, if lower detection limits were achieved, new perspectives to evaluate retention of low solubility contaminants in a wider range of geochemical conditions would be opened.A glass standard and a series of reference granite samples (Grimsel and Äspö), either enriched by sorption with natU and La or kept natural, have been scanned by PIXE at the New-AGLAE detection system, to test measurement protocols and assess the MDL's allowed by the five detectors system.

Chemistry of Airborne Particulate Matter in the Western Plains of Texas Using PIXE Analysis

USDA-ARS?s Scientific Manuscript database

Aerosol samples on polycarbonate filters were collected daily (for 24 hour periods) over several years in Lubbock, Reese Center, and Big Spring in the Southern High Plains region of western Texas, a region known for frequent dust storms. Twenty-seven filter samples representing a variety of particle...

Heavy metals in the atmosphere coming from a copper smelter in Chile

NASA Astrophysics Data System (ADS)

Romo-Kröger, C. M.; Morales, J. R.; Dinator, M. I.; Llona, F.; Eaton, L. C.

The Chilean mine El Teniente is the world's largest underground copper mine. It operates a giant smelter at Caletones (34° 7' S, 70° 27' W) and we have found it is the major source of air contamination in the region. In August 1991 a special circumstance occurred due to a labor strike, with total cessation of activities. A time series analysis of airborne particles collected at a site about 13 km from the smelter was performed in a period including the strike. The PIXE method and other techniques were used to analyse fine (<2.5 μm) and coarse (2.5-15 μm) particles on Nuclepore filters. S, Cu, Zn and As were quite enriched in normal working periods relative to the strike period. Elemental characterization of soil samples by radioactive source analysis demonstrated that this group of elements did not come from airborne soil dust. Cluster analyses of the interelement correlation matrices, resulting from PIXE data, showed one group (Si, K, Ca, Fe) with main origin in soil and another group (S, Cu, Zn, As) coming from the copper smelter.

Disentangling the major source areas for an intense aerosol advection in the Central Mediterranean on the basis of Potential Source Contribution Function modeling of chemical and size distribution measurements

NASA Astrophysics Data System (ADS)

Petroselli, Chiara; Crocchianti, Stefano; Moroni, Beatrice; Castellini, Silvia; Selvaggi, Roberta; Nava, Silvia; Calzolai, Giulia; Lucarelli, Franco; Cappelletti, David

2018-05-01

In this paper, we combined a Potential Source Contribution Function (PSCF) analysis of daily chemical aerosol composition data with hourly aerosol size distributions with the aim to disentangle the major source areas during a complex and fast modulating advection event impacting on Central Italy in 2013. Chemical data include an ample set of metals obtained by Proton Induced X-ray Emission (PIXE), main soluble ions from ionic chromatography and elemental and organic carbon (EC, OC) obtained by thermo-optical measurements. Size distributions have been recorded with an optical particle counter for eight calibrated size classes in the 0.27-10 μm range. We demonstrated the usefulness of the approach by the positive identification of two very different source areas impacting during the transport event. In particular, biomass burning from Eastern Europe and desert dust from Sahara sources have been discriminated based on both chemistry and size distribution time evolution. Hourly BT provided the best results in comparison to 6 h or 24 h based calculations.

Analysis of Venetian-type glass fragments from the ancient city of Lezha (Albania)

NASA Astrophysics Data System (ADS)

Šmit, Ž.; Stamati, F.; Civici, N.; Vevecka-Priftaj, A.; Kos, M.; Jezeršek, D.

2009-08-01

A series of glasses excavated in the Albanian city of Lezha (ancient Lissos) were analyzed by the combined PIXE-PIGE method in air and by source-excited XRF. The analysis revealed two types of glass that can be identified as façon de Venise glass and its subsequent younger phase, produced by chemically purer components and using As 2O 3 as decolorant.

Development and Commissioning of an External Beam Facility in the Union College Ion Beam Analysis Laboratory

NASA Astrophysics Data System (ADS)

Yoskowitz, Joshua; Clark, Morgan; Labrake, Scott; Vineyard, Michael

2015-10-01

We have developed an external beam facility for the 1.1-MV tandem Pelletron accelerator in the Union College Ion Beam Analysis Laboratory. The beam is extracted from an aluminum pipe through a 1 / 4 ' ' diameter window with a 7.5- μm thick Kapton foil. This external beam facility allows us to perform ion beam analysis on samples that cannot be put under vacuum, including wet samples and samples too large to fit into the scattering chamber. We have commissioned the new facility by performing proton induced X-ray emission (PIXE) analysis of several samples of environmental interest. These include samples of artificial turf, running tracks, and a human tooth with an amalgam filling. A 1.7-MeV external proton beam was incident on the samples positioned 2 cm from the window. The resulting X-rays were measured using a silicon drift detector and were analyzed using GUPIX software to determine the concentrations of elements in the samples. The results on the human tooth indicate that while significant concentrations of Hg, Ag, and Sn are present in the amalgam filling, only trace amounts of Hg appear to have leached into the tooth. The artificial turf and running tracks show rather large concentrations of a broad range of elements and trace amounts of Pb in the turf infill.

A comprehensive experimental characterization of the iPIX gamma imager

NASA Astrophysics Data System (ADS)

Amgarou, K.; Paradiso, V.; Patoz, A.; Bonnet, F.; Handley, J.; Couturier, P.; Becker, F.; Menaa, N.

2016-08-01

The results of more than 280 different experiments aimed at exploring the main features and performances of a newly developed gamma imager, called iPIX, are summarized in this paper. iPIX is designed to quickly localize radioactive sources while estimating the ambient dose equivalent rate at the measurement point. It integrates a 1 mm thick CdTe detector directly bump-bonded to a Timepix chip, a tungsten coded-aperture mask, and a mini RGB camera. It also represents a major technological breakthrough in terms of lightness, compactness, usability, response sensitivity, and angular resolution. As an example of its key strengths, an 241Am source with a dose rate of only few nSv/h can be localized in less than one minute.

Determination of Elemental Composition of Malabar spinach, Lettuce, Spinach, Hyacinth Bean, and Cauliflower Vegetables Using Proton Induced X-Ray Emission Technique at Savar Subdistrict in Bangladesh

PubMed Central

Fahad, S. M.; Islam, A. F. M. Mahmudul; Ahmed, Mahiuddin; Alam, Md. Rezaul; Alam, Md. Ferdous; Khalik, Md. Farhan; Hossain, Md. Lokman; Abedin, Md. Joynal

2015-01-01

The concentrations of 18 different elements (K, Ca, Fe, Cl, P, Zn, S, Mn, Ti, Cr, Rb, Co, Br, Sr, Ru, Si, Ni, and Cu) were analyzed in five selected vegetables through Proton Induced X-ray Emission (PIXE) technique. The objective of this study was to provide updated information on concentrations of elements in vegetables available in the local markets at Savar subdistrict in Bangladesh. These elements were found in varying concentrations in the studied vegetables. The results also indicated that P, Cl, K, Ca, Mn, Fe, and Zn were found in all vegetables. Overall, K and Ca exhibited the highest concentrations. Cu and Ni exhibited the lowest concentrations in vegetables. The necessity of these elements was also evaluated, based on the established limits of regulatory standards. The findings of this study suggest that the consumption of these vegetables is not completely free of health risks. PMID:26229953

One Click to the Cosmos: The AstroPix Image Archive

NASA Astrophysics Data System (ADS)

Hurt, Robert L.; Llamas, J.; Squires, G. K.; Brinkworth, C.; X-ray Center, Chandra; ESO/ESA; Science Center, Spitzer; STScI

2013-01-01

Imagine a single website that acts as a portal to the entire wealth of public imagery spanning the world's observatories. This is the goal of the AstroPix project (astropix.ipac.caltech.edu), and you can use it today! Although still in a beta development state, this past year has seen the inclusion of thousands of images spanning some of the most prominent observatories in the world, including Chandra, ESO, Galex, Herschel, Hubble, Spitzer, and WISE, with more on the way. The archive is unique as it is built around the Astronomical Visualization Metadata (AVM) standard, which captures the rich contextual information for each image. This ranges from titles and descriptions, to color representations and observation details, to sky coordinates. AVM enables AstroPix imagery to be used in a variety of unique ways that benefit formal and informal education as well as astronomers and the general public. Visitors to Astropix can search the database using simple free-text queries, or use a structured search (similar to "Smart Playlists" found in iTunes, for example). We are also developing public application programming interfaces (APIs) to allow third party software and websites to access the growing content for a variety of uses (planetarium software, museum kiosks, mobile apps, and creative web interfaces, to name a few). Contributing image assets to AstroPix is as easy as tagging the images with the relevant metadata and including the web links to the images in a simple RSS feed. We will cover some of the latest information about tools to contribute images to AstroPix and ways to use the site.

ESO and NSF Sign Agreement on ALMA

NASA Astrophysics Data System (ADS)

2003-02-01

Green Light for World's Most Powerful Radio Observatory On February 25, 2003, the European Southern Observatory (ESO) and the US National Science Foundation (NSF) are signing a historic agreement to construct and operate the world's largest and most powerful radio telescope, operating at millimeter and sub-millimeter wavelength. The Director General of ESO, Dr. Catherine Cesarsky, and the Director of the NSF, Dr. Rita Colwell, act for their respective organizations. Known as the Atacama Large Millimeter Array (ALMA), the future facility will encompass sixty-four interconnected 12-meter antennae at a unique, high-altitude site at Chajnantor in the Atacama region of northern Chile. ALMA is a joint project between Europe and North America. In Europe, ESO is leading on behalf of its ten member countries and Spain. In North America, the NSF also acts for the National Research Council of Canada and executes the project through the National Radio Astronomy Observatory (NRAO) operated by Associated Universities, Inc. (AUI). The conclusion of the ESO-NSF Agreement now gives the final green light for the ALMA project. The total cost of approximately 650 million Euro (or US Dollars) is shared equally between the two partners. Dr. Cesarsky is excited: "This agreement signifies the start of a great project of contemporary astronomy and astrophysics. Representing Europe, and in collaboration with many laboratories and institutes on this continent, we together look forward towards wonderful research projects. With ALMA we may learn how the earliest galaxies in the Universe really looked like, to mention but one of the many eagerly awaited opportunities with this marvellous facility". "With this agreement, we usher in a new age of research in astronomy" says Dr. Colwell. "By working together in this truly global partnership, the international astronomy community will be able to ensure the research capabilities needed to meet the long-term demands of our scientific enterprise, and that we will be able to study and understand our universe in ways that have previously been beyond our vision". The recent Presidential decree from Chile for AUI and the agreement signed in late 2002 between ESO and the Government of the Republic of Chile (cf. ESO PR 18/02) recognize the interest that the ALMA Project has for Chile, as it will deepen and strengthen the cooperation in scientific and technological matters between the parties. A joint ALMA Board has been established which oversees the realisation of the ALMA project via the management structure. This Board meets for the first time on February 24-25, 2003, at NSF in Washington and will witness this historic event. ALMA: Imaging the Light from Cosmic Dawn ESO PR Photo 06a/03 ESO PR Photo 06a/03 [Preview - JPEG: 588 x 400 pix - 52k [Normal - JPEG: 1176 x 800 pix - 192k] [Hi-Res - JPEG: 3300 x 2244 pix - 2.0M] ESO PR Photo 06b/03 ESO PR Photo 06b/03 [Preview - JPEG: 502 x 400 pix - 82k [Normal - JPEG: 1003 x 800 pix - 392k] [Hi-Res - JPEG: 2222 x 1773 pix - 3.0M] ESO PR Photo 06c/03 ESO PR Photo 06c/03 [Preview - JPEG: 474 x 400 pix - 84k [Normal - JPEG: 947 x 800 pix - 344k] [Hi-Res - JPEG: 2272 x 1920 pix - 2.0M] ESO PR Photo 06d/03 ESO PR Photo 06d/03 [Preview - JPEG: 414 x 400 pix - 69k [Normal - JPEG: 828 x 800 pix - 336k] [HiRes - JPEG: 2935 x 2835 pix - 7.4k] Captions: PR Photo 06a/03 shows an artist's view of the Atacama Large Millimeter Array (ALMA), with 64 12-m antennae. PR Photo 06b/03 is another such view, with the array arranged in a compact configuration at the high-altitude Chajnantor site. The ALMA VertexRSI prototype antennae is shown in PR Photo 06c/03 on the Antenna Test Facility (ATF) site at the NRAO Very Large Array (VLA) site near Socorro (New Mexico, USA). The future ALMA site at Llano de Chajnantor at 5000 metre altitude, some 40 km East of the village of San Pedro de Atacama (Chile) is seen in PR Photo 06d/03 - this view was obtained at 11 hrs in the morning on a crisp and clear autumn day (more views of this site are available at the Chajnantor Photo Gallery). The Atacama Large Millimeter Array (ALMA) will be one of astronomy's most powerful telescopes - providing unprecedented imaging capabilities and sensitivity in the corresponding wavelength range, many orders of magnitude greater than anything of its kind today. ALMA will be an array of 64 antennae that will work together as one telescope to study millimeter and sub-millimeter wavelength radiation from space. This radiation crosses the critical boundary between infrared and microwave radiation and holds the key to understanding such processes as planet and star formation, the formation of early galaxies and galaxy clusters, and the formation of organic and other molecules in space. "ALMA will be one of astronomy's premier tools for studying the universe" says Nobel Laureate Riccardo Giacconi, President of AUI (and former ESO Director General (1993-1999)). "The entire astronomical community is anxious to have the unprecedented power and resolution that ALMA will provide". The President of the ESO Council, Professor Piet van der Kruit, agrees: "ALMA heralds a break-through in sub-millimeter and millimeter astronomy, allowing some of the most penetrating studies the Universe ever made. It is safe to predict that there will be exciting scientific surprises when ALMA enters into operation". What is millimeter and sub-millimeter wavelength astronomy? Astronomers learn about objects in space by studying the energy emitted by those objects. Our Sun and the other stars throughout the Universe emit visible light. But these objects also emit other kinds of light waves, such as X-rays, infrared radiation, and radio waves. Some objects emit very little or no visible light, yet are strong sources at other wavelengths in the electromagnetic spectrum. Much of the energy in the Universe is present in the sub-millimeter and millimeter portion of the spectrum. This energy comes from the cold dust mixed with gas in interstellar space. It also comes from distant galaxies that formed many billions of years ago at the edges of the known universe. With ALMA, astronomers will have a uniquely powerful facility with access to this remarkable portion of the spectrum and hence, new and wonderful opportunities to learn more about those objects. Current observatories simply do not have anywhere near the necessary sensitivity and resolution to unlock the secrets that abundant sub-millimeter and millimeter wavelength radiation can reveal. It will take the unparalleled power of ALMA to fully study the cosmic emission at this wavelength and better understand the nature of the universe. Scientists from all over the world will use ALMA. They will compete for observing time by submitting proposals, which will be judged by a group of their peers on the basis of scientific merit. ALMA's unique capabilities ALMA's ability to detect remarkably faint sub-millimeter and millimeter wavelength emission and to create high-resolution images of the source of that emission gives it capabilities not found in any other astronomical instruments. ALMA will therefore be able to study phenomena previously out of reach to astronomers and astrophysicists, such as: * Very young galaxies forming stars at the earliest times in cosmic history; * New planets forming around young stars in our galaxy, the Milky Way; * The birth of new stars in spinning clouds of gas and dust; and * Interstellar clouds of gas and dust that are the nurseries of complex molecules and even organic chemicals that form the building blocks of life. How will ALMA work? All of ALMA's 64 antennae will work in concert, taking quick "snapshots" or long-term exposures of astronomical objects. Cosmic radiation from these objects will be reflected from the surface of each antenna and focussed onto highly sensitive receivers cooled to just a few degrees above absolute zero in order to suppress undesired "noise" from the surroundings. There the signals will be amplified many times, digitized, and then sent along underground fiber-optic cables to a large signal processor in the central control building. This specialized computer, called a correlator - running at 16,000 million-million operations per second - will combine all of the data from the 64 antennae to make images of remarkable quality. The extraordinary ALMA site Since atmospheric water vapor absorbs millimeter and (especially) sub-millimeter waves, ALMA must be constructed at a very high altitude in a very dry region of the earth. Extensive tests showed that the sky above the Atacama Desert of Chile has the excellent clarity and stability essential for ALMA. That is why ALMA will be built there, on Llano de Chajnantor at an altitude of 5,000 metres in the Chilean Andes. A series of views of this site, also in high-resolution suitable for reproduction, is available at the Chajnantor Photo Gallery. Timeline for ALMA June 1998: Phase 1 (Research and Development) June 1999: European/American Memorandum of Understanding February 2003: Signature of the bilateral Agreement 2004: Tests of the Prototype System 2007: Initial scientific operation of a partially completed array 2011: End of construction of the array

Sizes of particles formed during municipal wastewater treatment.

PubMed

Lech, Smoczynski; Marta, Kosobucka; Michal, Smoczynski; Harsha, Ratnaweera; Krystyna, Pieczulis-Smoczynska

2017-02-01

Volumetric diameters Dv and specific surface area SpS of sludge particles formed during chemical coagulation and electrocoagulation of sewage were determined. The obtained aggregate-flocs differed substantially in both Dv and SpS values. The differences in Dv and SpS values of the analyzed particles were interpreted based on theoretical models for expanding aggregates. The most uniform particles were formed under exposure to: (a) optimal and maximal doses of PIX, (b) optimal doses of PAX, (c) maximal doses of the Al electro-coagulant. The lowest PIX dose produced the least uniform particles. Sludge aggregates-particles produced under exposure to minimal doses of PIX and the Al electro-coagulant were characterized by the lowest SpS values. Sludge particles coagulated by PAX and the particles formed at higher doses of PIX and the Al electro-coagulant had higher SpS values. The particles formed at all doses of the applied coagulants and electro-coagulants were generally classified into two size ranges: the main range and the secondary range. Most particles belonged to the main size range. An increase in the percentage of colloidal hydroxide particles in sewage sludge increased SpS.

Study of Italian Renaissance sculptures using an external beam nuclear microprobe

NASA Astrophysics Data System (ADS)

Zucchiatti, A.; Bouquillon, A.; Moignard, B.; Salomon, J.; Gaborit, J. R.

2000-03-01

The use of an extracted proton micro-beam for the PIXE analysis of glazes is discussed in the context of the growing interest in the creation of an analytical database on Italian Renaissance glazed terracotta sculptures. Some results concerning the frieze of an altarpiece of the Louvre museum, featuring white angels and cherubs heads, are presented.

Quantification of indium in steel using PIXE

NASA Astrophysics Data System (ADS)

Oliver, A.; Miranda, J.; Rickards, J.; Cheang, J. C.

1989-04-01

The quantitative analysis of steel for endodontics tools was carried out using low-energy protons (≤ 700 keV). A computer program for a thick-target analysis which includes enhancement due to secondary fluorescence was used. In this experiment the L-lines of indium are enhanced due to the proximity of other elements' K-lines to the indium absorption edge. The results show that the ionization cross section expression employed to evaluate this magnitude is important.

Werner Brandt legacy to PIXE: Past and present perspectives

NASA Astrophysics Data System (ADS)

Lapicki, Gregory

2014-01-01

Inner-shell ionization cross sections used in Particle-Induced X-ray Elemental (PIXE) analyses are routinely calculated in the ECPSSR [W. Brandt, G. Lapicki, Phys. Rev. A 23 (1981) 1717-1729] theory and/or semiempirical formulas scaled to that theory. Thirty years after the passing of Werner Brandt, with recognition of his seminal contributions to other research on positron physics and stopping power problems, the work and articles that progressed into the ECPSSR theory for inner-shell ionization by protons and heavier ions are recalled as Brandt's past legacy to the PIXE community. Applications of the ECPSSR and its evolution into the ECUSAR [G. Lapicki, Nucl. Instr. Meth. B 189 (2002) 8-20] theory over the last three decades are reviewed with perspectives on Brandt's present legacy.

The Glory of a Nearby Star

NASA Astrophysics Data System (ADS)

2001-08-01

Optical Light from a Hot Stellar Corona Detected with the VLT Summary The solar corona is a beautiful sight during total solar eclipses . It is the uppermost region of the extended solar atmosphere and consists of a very hot (over 1 million degrees), tenuous plasma of highly ionised elements that emit strong X-ray radiation. There is also a much weaker coronal emission in the optical part of the spectrum . The Sun is a normal star and X-ray observations from rockets and orbiting X-ray telescopes have shown that many other stars also possess coronae . But due to observational limits of the telescopes available so far, the much fainter optical emission from stellar coronae had never been detected. Now, however, an optical coronal line from iron ions that have lost 12 electrons (Fe XIII) has for the first time been observed in a star other than the Sun . The object, a cool star named CN Leonis , is located at a distance of 8 light-years. This impressive observational feat was performed with the UV-Visual Echelle Spectrograph (UVES) on the VLT 8.2-m KUEYEN telescope at the ESO Paranal Observatory , within a programme by German astronomer Jürgen Schmitt and his collaborators at the University of Hamburg Observatory. The possibility to observe stellar coronae with ground-based telescopes opens up new and exciting research opportunities, including the detailed study of stellar cycles , similar to the 11-year solar period. PR Photo 24a/01 : The solar corona during the August 11, 1999, solar eclipse. PR Photo 24b/01 : The nearby star CN Leonis . PR Photo 24c/01 : Ultraviolet spectrum of CN Leonis , obtained with UVES at VLT KUEYEN. PR Photo 24d/01 : The coronal Fe XIII emission line at 3388 Ångstrom in CN Leonis . The 'coronium' mystery ESO PR Photo 24a/01 ESO PR Photo 24a/01 [Preview - JPEG: 450 x 400 pix - 26k] [Normal - JPEG: 899 x 800 pix - 328k] [HiRes - JPEG: 3000 x 2669 pix - 3.1Mk] Caption : Photo of the solar corona, obtained by Philippe Duhoux (ESO) on August 11, 1999. Two years ago, on August 11, 1999, the shadow of the Moon moved rapidly across Europe and millions of eager observers experienced a total solar eclipse , many for the first time in their lives. Those who had a clear view during the 2-min phase of totality were able to see the glorious solar corona , a shimmering halo of light around the eclipsed solar disk, cf. PR Photo 24a/01 . Some 130 years earlier, during a total solar eclipse on August, 7, 1869, American astronomers William Harkness and Charles Young observed a weak spectral emission line from the solar corona in the green region of the spectrum; it was visible for a couple of minutes. However, despite an enormous amount of work, both at the telescope during subsequent eclipses and in the laboratory, this emission line could not be attributed to any known chemical element. As the years passed, the mystery of the origin of this emission line deepened and some astronomers went as far as introducing an entirely new element named 'coronium' [1]. As better instruments became available, more coronal lines were seen during later solar eclipses. A hot corona It was only after 70 years that the coronium mystery was finally solved by two astrophysicists, Walter Grotrian from Germany and Bengt Edlén from Sweden. They showed that two observed emission lines arise from iron atoms which have lost about half their 26 electrons . By 1941, all of the coronal lines had been found to originate from such highly 'ionized atoms' . The successful identification created, however, another puzzle: in order to strip iron atoms of half of their electrons, temperatures of more than one million degrees are required, yet the temperature of the surface of the Sun is only of the order of 5500 °C! The astronomers in the 1940's were well aware that the Sun's energy is produced in the interior and that heat flows outwards from hotter to cooler regions. So how could there be a much hotter corona above the cooler photosphere? Since then, much research effort has been aimed at understanding the transport of energy in the solar atmosphere and it appears that several mechanisms play a role, including magnetic and other effects. Nevertheless, a full and detailed explanation of the high temperature of the solar corona is still outstanding. X-rays from the solar and stellar coronae An ionized gas (a 'plasma' ) at temperatures of a million or more degrees emits most of its energy at short X-ray wavelengths. X-rays do not penetrate the Earth's atmosphere and can therefore only be studied from space. Soon after World War II, the predicted X-ray emission from the solar corona was detected by American astrophysicist Herbert Friedman and his colleagues, using an X-ray detector onboard a German V-2 rocket, and hereby inaugurating the rich field of solar X-ray astronomy [1]. The Sun is a quite normal star and other stars therefore ought to possess coronae as well. Still, it took nearly 30 years until X-ray emission from other normal stars was finally detected. While X-rays from several distant objects (including the Crab Nebula, the Galactic Centre and the quasar 3C273) were discovered during the 1960's, it was only in 1975 that X-rays were registered from the bright, normal star Capella (Alpha Aurigae) during a rocket flight to study other X-ray sources. In fact, this discovery was accidental, as Capella happened to be used as a 'guide star' while the pointing direction of the rocket was ''hopping'' from one object to the next. Quite surprisingly, Capella was found to be a very strong emitter of X-rays, corresponding to an intrinsic level of more than 1000 times that of the solar corona. This discovery laid the foundation for the subsequent detection of X-ray emission from tens of thousand of stars by means of X-ray satellites, e.g., by the Einstein Observatory and especially by ROSAT. All these observations showed that stellar coronae must be a very common phenomenon . Observation of stellar coronal lines Given this widespread occurrence of stellar coronae, Jürgen Schmitt and his collaborators at the University of Hamburg (Germany) asked themselves the natural question: "What about coronal line emission from other stars in the optical (visible) region of the spectrum ? Wouldn't it be a good idea to observe coronal emission from other stars with ground-based telescopes ? In any case, observations from the ground are easier to perform and are also more economical than from space" . This may be easy to say, but it is much harder to do. The main problem is the same as when observing the solar corona. The solar coronal emission lines in the visible region of the spectrum are always observed above the solar limb. If one were to try to detect these weak lines in front of the solar disk, they would "drown" in the strong background light from the solar 'surface' (the photosphere). The original discovery of coronal emission in 1869 was indeed obtained during a solar eclipse, when this strong light is completely blocked out by the Moon. However, current telescopes are unfortunately unable to block out the light from a stellar disk in a similar way in order to make its corona visible; the angular size of the disk is too small and the positional accuracy needed for such an observation is too high for it to be feasible with present techniques. The only way forward is then a direct attempt to detect the faint coronal emission against the much higher background of the stellar disk - and that is exactly why a very large telescope is needed for such an observational feat. Selecting the target star: CN Leonis ESO PR Photo 24b/01 ESO PR Photo 24b/01 [Preview - JPEG: 681 x 400 pix - 73k] [Normal - JPEG: 1362 x 800 pix - 616k] Caption : Images of the nearby, variable star CN Leonis , in which a coronal emission line has been observed with the UVES spectrograph at the 8.2-m VLT KUEYEN telescope. This star is relatively nearby (8 light-years) and moves about 5 arcsec/yr in the sky, approximately towards south-west (the 4 o'clock direction). The motion is clearly visible on these two images obtained with the UK Schmidt telescope and reproduced from the Second Digized Sky Survey (DSS-2); the blue image (left) was taken several years before the red one (right). Moreover, the red colour of the star is obvious; the red image is clearly brighter than the blue one. The field measures 5 x 5 arcmin 2 ; North is up and East is left. These DSS-2 images are copyright by the UK SERC/PPARC (Particle Physics and Astronomy Research Council, formerly Science and Engineering Research Council), the Anglo-Australian Telescope Board and the Association of Universities for Research in Astronomy (AURA). In order to increase the chances of success, Jürgen Schmitt and his colleagues decided to focus on optically faint, red dwarf stars . Such stars may have the same X-ray output (or even larger) than the Sun, and hence presumably possess pronounced coronae, yet their disks emit over one thousand times less visible light than does that of the Sun. They first turned their attention towards an optically faint (visual magnitude 14) and nearby (distance 8 light-years) red dwarf star (of type M5.5) known as CN Leonis , cf. PR Photo 24b/01 . It is located slightly north of the celestial equator in the constellation Leo (the Lion) and the two-letter name indicates that it is a variable star. It has been found to undergo sudden brightenings (it is a 'flare star' ), and exhibits strong magnetic activity. It is also a source of strong X-rays which the German astronomers had previously studied with the ROSAT satellite observatory and they therefore considered this star as an excellent first choice for a coronal study with the VLT. UVES detects a coronal line in the visible spectral region ESO PR Photo 24c/01 ESO PR Photo 24c/01 [Preview - JPEG: 400 x 471 pix - 31k] [Normal - JPEG: 800 x 942 pix - 81k] [Hi-Res - JPEG: 2549 x 3000 pix - 496k] ESO PR Photo 24d/01 ESO PR Photo 24d/01 [Preview - JPEG: 400 x 489 pix - 43k] [Normal - JPEG: 800 x 978 pix - 168k] Caption : Left: A small part of the near-ultraviolet spectrum of CN Leonis , obtained with UVES at the 8.2-m VLT KUEYEN telescope in January 2001, showing many emission lines from nickel atoms (Ni I) and titanium ions (Ti II). Right: "Decomposition" of an emission line at wavelength 3388.1 Ångstrom (338.81 nm) into two components. The observed spectral intensity is indicated by the 'step'-curve (in blue). As will be seen, the sum (fully drawn red line) of a strong and narrow line from titanium ions (Ti II) in the stellar chromosphere (dashed, in red) and an underlying, much broader, coronal line from 12 times ionised iron (Fe XIII; dashed, in red, slightly to the right of the titanium line) fits the observed spectral intensity curve perfectly, cf. the text. A spectrum of CN Leonis was obtained with the VLT UV-Visual Echelle Spectrograph on January 6, 2001. The spectrum covers a wide spectral region and is extremely rich in emission lines, but the team was mainly interested in one particular emission line, seen in the ultraviolet part of the spectrum at wavelength 3388.1 Ångstrom (338.81 nm). This is the wavelength at which a coronal emission line arising from 12 times ionised iron (denoted as Fe 12+ or Fe XIII ) is seen in the solar spectrum. Would the same line be visible in the spectrum of CN Leo as well ? When first inspecting the spectrum of CN Leonis ( PR Photo 24c/01 ), Jürgen Schmitt was hopeful: "We saw a strong line, right at the proper location!" But then, he explains, "we soon learned that life is never as easy as expected... that line had a rather strange appearance and something seemed to be wrong". Indeed, the early investigation showed that this line feature might be attributed to emission by singly ionised titanium atoms ( Ti + or Ti II ), located in a lower atmospheric layer (the 'chromosphere' ) and not in the corona of CN Leo . However, a subsequent, very careful study definitively proved the presence of the hoped-for coronal emission line . The titanium line is produced at lower temperatures than those that reign in the corona, and the individual velocities of the titanium ions are thus much slower than those of the iron ions in the corona. The broadening of the titanium line, introduced by the Doppler effect (the combined lineshifts by all ions), must therefore be much less. The titanium line must accordingly be much more narrow than any coronal line. Many other titanium emission lines are visible in the UVES spectrum, and the common width of these lines can be determined with high accuracy. It turns out to be much less than the observed width of the line seen at 3388 Ångstrom, and that line can therefore not be due to titanium alone. And indeed, when 'subtracting' the contribution from the narrow titanium line, an underlying, much broader line emerges and becomes well visible - cf. PR Photo 24d/01 - it is indeed the coronal emission line from 12 times ionised iron (Fe XIII). This is the first time a stellar coronal line has been unambiguously observed in the optical part of the spectrum. Prospects This KUEYEN/UVES detection of a coronal line closes the historical loop to the discovery of the solar corona as a tenuous, hot envelope around the Sun. It now opens up a new window for the study of stellar coronae and allows thermal emission from these hot regions to be studied from the ground and not only from space, as this was the case until now. Thus, it is now feasible to use the superb capabilities of ground-based instrumentation which has much higher spectral resolving power than currently available X-ray spectrometers. With the new tools at large telescopes like the VLT, the astronomers may embark on detailed studies of the dynamics of stellar coronae. They will then also be able to watch the expected changes in the emission levels of other stars, similar to the well-known 11-year cycle of the Sun. Eventually, they may also obtain images of stellar chromospheres and coronae. More information The research reported in this Press Release is described in a scientific article ("Light from Stellar Coronae: Ground-based Discovery of Emission Lines" by Jürgen Schmitt and Reiner Wichmann ) that appears in the August 2, 2001, issue of the scientific journal "Nature". Jürgen Schmitt has written a popular account on stellar X-ray emission in the German language journal "Sterne und Weltraum" (July 2001, page 544). Note [1]: A report on the observations of the 1869 solar eclipse appeared in the first Nature issue (November 4, 1869) and the interesting story about the identification of the solar coronal lines is described in a popular article ( John Talbot ). A talk by Herbert Friedman about the evolution of X-Ray Astronomy includes a description of the 1949 detection of solar emission in this waveband. More details about the solar-stellar connection and X-rays may be found in the article by Berhard Haisch and Jürgen Schmitt in the October 1999 issue of the journal "Sky & Telescope" (page 46).

Combined PIXE and SEM study of the behaviour of trace elements in gel formed around implant coated with bioactive glass

NASA Astrophysics Data System (ADS)

Oudadesse, H.; Irigaray, J. L.; Barbotteau, Y.; Brun, V.; Moretto, Ph.

2002-05-01

Bioactive glasses are used as coating biomaterials to facilitate anchorage of metallic prostheses implanted into the body. The aim of this work is to study the behavior of gel formed in contact with alloys and BVA and BVH bioactive glasses implanted. Cylinders of metallic implants composed by Ti, Al and V, are coated with bioactive glass. Three sheep were implanted for different time length: 3, 6 and 12 months in the femoral epiphysis. Results obtained with particle induced X-ray emission and scanning electron microscopy show that BVA coating induces a better contact between the metallic implant and bone. On the other hand, BVH coating prevents corrosion from the metallic implant.

Technology: Computer Applications for Young Users--BumperCar and KidPix

ERIC Educational Resources Information Center

Van Horn, Royal

2004-01-01

There is a lot of software available for young children, but there are not many applications designed especially for them. This situation may be about to change with the release of BumperCar and a new version of KidPix, both of which recently earned awards from MacWorld magazine. In this article, the author describes this new software and how it…

Evaluation of cryoanalysis as a tool for analyzing elemental distribution in "live" tardigrades using micro-PIXE

NASA Astrophysics Data System (ADS)

Nilsson, E. J. C.; Pallon, J.; Przybylowicz, W. J.; Wang, Y. D.; Jönsson, K. I.

2014-08-01

Although heavy on labor and equipment, thus not often applied, cryoanalysis of frozen hydrated biological specimens can provide information that better reflects the living state of the organism, compared with analysis in the freeze-dried state. In this paper we report a study where the cryoanalysis facility with cryosectioning capabilities at Materials Research Department, iThemba LABS, South Africa was employed to evaluate the usefulness of combining three ion beam analytical methods (μPIXE, RBS and STIM) to analyze a biological target where a better elemental compositional description is needed - the tardigrade. Imaging as well as quantification results are of interest. In a previous study, the element composition and redistribution of elements in the desiccated and active states of two tardigrade species was investigated. This study included analysis of both whole and sectioned tardigrades, and the aim was to analyze each specimen twice; first frozen hydrated and later freeze-dried. The combination of the three analytical techniques proved useful: elements from C to Rb in the tardigrades could be determined and certain differences in distribution of elements between the frozen hydrated and the freeze-dried states were observed. RBS on frozen hydrated specimens provided knowledge of matrix elements.

Characterization of the air pollution in the urban area of Madrid

NASA Astrophysics Data System (ADS)

Climent-Font, Aurelio; Swietlicki, Erik; Revuelta, Antonio

1994-03-01

An attempt is made to characterize for the first time the urban pollution of Madrid using the combination of conventional gas measurements and an ion beam analytical technique (PIXE) for aerosol monitoring. Different sets of samples were collected selecting different seasons of the year; winter and summer 1992, and also different sampling times; 3 h and 24 h. A group of 18 elements in the mass range from Si to Pb could be analyzed. Concentration of gases in the air was recorded for the following: CO, NO x, NO 2, SO 2 and C xH y. Four sources contributing to the air pollution were obtained by means of absolute principal component analysis where automotive transport emerges as the dominating one. The combination of aerosol (PIXE) and gas data as input to a receptor model proved to be fruitful for the understanding of the underlying chemical and physical processes governing the observed pollution levels. This is a preliminary study whose results will supply the trends and strategies for a more thorough characterization.

Micro-PIXE investigation of bean seeds to assist micronutrient biofortification

NASA Astrophysics Data System (ADS)

Cvitanich, Cristina; Przybyłowicz, Wojciech J.; Mesjasz-Przybyłowicz, Jolanta; Blair, Matthew W.; Astudillo, Carolina; Orłowska, Elżbieta; Jurkiewicz, Anna M.; Jensen, Erik Ø.; Stougaard, Jens

2011-10-01

This study compares the distribution and concentrations of micro- and macronutrients in different bean cultivars with the aim of optimizing the biofortification, a sustainable approach towards improving dietary quality. Micro-PIXE was used to reveal the distribution of Fe, Zn, Mn, Ca, P, S in seeds of common beans (Phaseolus vulgaris) and runner beans (Phaseolus coccineus). Average concentrations of elements in different tissues were obtained using ICP-AES. The highest concentrations of Zn in the studied beans were found in the embryonic axis, but an increased concentration of this element was also detected in the provascular bundles of the cotyledons. The first layer of cells surrounding provascular bundles accumulated high concentrations of Fe, while the next cell layer had an increased concentration of Mn. The analysis showed that the provascular bundles and the first cell layers surrounding them could have a significant role in the storage of important seed micronutrients - Zn, Fe, and Mn. This information has important implications for molecular biology studies aimed at seed biofortification.

Spectral structure of a polycapillary lens shaped X-ray beam

NASA Astrophysics Data System (ADS)

Gogolev, A. S.; Filatov, N. A.; Uglov, S. R.; Hampai, D.; Dabagov, S. B.

2018-04-01

Polycapillary X-ray optics is widely used in X-ray analysis techniques to create a small secondary source, for instance, or to deliver X-rays to the point of interest with minimum intensity losses [1]. The main characteristics of the analytical devices on its base are the size and divergence of the focused or translated beam. In this work, we used the photon-counting pixel detector ModuPIX to study the parameters for polycapillary focused X-ray tube radiation as well as the energy and spatial dependences of radiation at the focus. We have characterized the high-speed spectral camera ModuPIX, which is a single Timepix device with a fast parallel readout allowing up to 850 frames per second with 256 × 256 pixels and a 55 μm pitch defined by the frame frequency. By means of the silicon monochromator the energy response function is measured in clustering mode by the energy scan over total X-ray tube spectrum.

Resorption kinetics of four hydroxyapatite-based ceramics by particle induced X-ray emission and neutron activation analysis

NASA Astrophysics Data System (ADS)

Jallot, E.; Irigaray, J. L.; Oudadesse, H.; Brun, V.; Weber, G.; Frayssinet, P.

1999-05-01

From the viewpoint of hard tissue response to implant materials, calcium phosphates are probably the most compatible materials presently known. During the last few years, much attention has been paid to hydroxyapatite and β-tricalcium phosphate as potential biomaterials for bone substitute. A good implantation of biomaterials in the skeleton is to reach full integration of non-living implant with living bone. The aim of this study is to compare the resorption kinetics of four kinds of calcium phosphate ceramics: hydroxyapatite (Ca{10}(PO4)6(OH)2), hydroxyapatite doped with manganese or zinc and a composite material of 75% hydroxyapatite and 25% β-tricalcium phosphate (Ca3(PO4)2). Cylinders (5 6 mm in diameter) of these ceramics were packed into holes made in the femur diaphysis of mature ovine. At 2, 4, 8, 12, 16, 20, 28, 36 and 48 weeks after the operation, bone/implant interface was embedded in polymethylmethacrylate. We used the PIXE method (particle induced X-ray emission) to measure the distribution of mineral elements (Ca, P, Sr, Zn, Mn and Fe) at the bone/implant interface. At 4, 8, 16, 28 and 48 weeks after implantation we studied a biopsy of the ceramics by neutron activation method. Then, we have a global measurement of mineral elements in the biomaterial. The results showed that the resorption kinetics of hydroxyapatite doped with zinc was faster than that of the three other bioceramics.

A comparison of two micro-beam X-ray emission techniques for actinide elemental distribution in microscopic particles originating from the hydrogen bombs involved in the Palomares (Spain) and Thule (Greenland) accidents

NASA Astrophysics Data System (ADS)

Jimenez-Ramos, M. C.; Eriksson, M.; García-López, J.; Ranebo, Y.; García-Tenorio, R.; Betti, M.; Holm, E.

2010-09-01

In order to validate and to gain confidence in two micro-beam techniques: particle induced X-ray emission with nuclear microprobe technique (μ-PIXE) and synchrotron radiation induced X-ray fluorescence in a confocal alignment (confocal SR μ-XRF) for characterization of microscopic particles containing actinide elements (mixed plutonium and uranium) a comparative study has been performed. Inter-comparison of the two techniques is essential as the X-ray production cross-sections for U and Pu are different for protons and photons and not well defined in the open literature, especially for Pu. The particles studied consisted of nuclear weapons material, and originate either in the so called Palomares accident in Spain, 1966 or in the Thule accident in Greenland, 1968. In the determination of the average Pu/U mass ratios (not corrected by self-absorption) in the analysed microscopic particles the results from both techniques show a very good agreement. In addition, the suitability of both techniques for the analysis with good resolution (down to a few μm) of the Pu/U distribution within the particles has been proved. The set of results obtained through both techniques has allowed gaining important information concerning the characterization of the remaining fissile material in the areas affected by the aircraft accidents. This type of information is essential for long-term impact assessments of contaminated sites.

Daily and hourly chemical impact of springtime transboundary aerosols on Japanese air quality

NASA Astrophysics Data System (ADS)

Moreno, T.; Kojima, T.; Amato, F.; Lucarelli, F.; de la Rosa, J.; Calzolai, G.; Nava, S.; Chiari, M.; Alastuey, A.; Querol, X.; Gibbons, W.

2013-02-01

The regular eastward drift of transboundary aerosol intrusions from the Asian mainland into the NW Pacific region has a pervasive impact on air quality in Japan, especially during springtime. Analysis of 24-h filter samples with Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and Mass Spectrometry (ICP-MS), and hourly Streaker with Particle Induced X-ray Emission (PIXE) samples collected continuously for six weeks reveal the chemistry of successive waves of natural mineral desert dust ("Kosa") and metalliferous sulphatic pollutants arriving in western Japan during spring 2011. The main aerosol sources recognised by Positive Matrix Factorization (PMF) analysis of Streaker data are mineral dust and fresh sea salt (both mostly in the coarser fraction PM2.5-10), As-bearing sulphatic aerosol (PM0.1-2.5), metalliferous sodic particulate matter (PM) interpreted as aged, industrially contaminated marine aerosol, and ZnCu-bearing aerosols. Whereas mineral dust arrivals are typically highly transient, peaking over a few hours, sulphatic intrusions build up and decline more slowly, and are accompanied by notable rises in ambient concentrations of metallic trace elements such as Pb, As, Zn, Sn and Cd. The magnitude of the loss in regional air quality due to the spread and persistence of pollution from mainland Asia is especially clear when cleansing oceanic air advects westward across Japan, removing the continental influence and reducing concentrations of the undesirable metalliferous pollutants by over 90%. Our new chemical database, especially the Streaker data, demonstrates the rapidly changing complexity of ambient air inhaled during these transboundary events, and implicates Chinese coal combustion as the main source of the anthropogenic aerosol component.

Feeling the Heat

NASA Astrophysics Data System (ADS)

2004-05-01

Successful "First Light" for the Mid-Infrared VISIR Instrument on the VLT Summary Close to midnight on April 30, 2004, intriguing thermal infrared images of dust and gas heated by invisible stars in a distant region of our Milky Way appeared on a computer screen in the control room of the ESO Very Large Telescope (VLT). These images mark the successful "First Light" of the VLT Imager and Spectrometer in the InfraRed (VISIR), the latest instrument to be installed on this powerful telescope facility at the ESO Paranal Observatory in Chile. The event was greeted with a mixture of delight, satisfaction and some relief by the team of astronomers and engineers from the consortium of French and Dutch Institutes and ESO who have worked on the development of VISIR for around 10 years [1]. Pierre-Olivier Lagage (CEA, France), the Principal Investigator, is content : "This is a wonderful day! A result of many years of dedication by a team of engineers and technicians, who can today be proud of their work. With VISIR, astronomers will have at their disposal a great instrument on a marvellous telescope. And the gain is enormous; 20 minutes of observing with VISIR is equivalent to a whole night of observing on a 3-4m class telescope." Dutch astronomer and co-PI Jan-Willem Pel (Groningen, The Netherlands) adds: "What's more, VISIR features a unique observing mode in the mid-infrared: spectroscopy at a very high spectral resolution. This will open up new possibilities such as the study of warm molecular hydrogen most likely to be an important component of our galaxy." PR Photo 16a/04: VISIR under the Cassegrain focus of the Melipal telescope PR Photo 16b/04: VISIR mounted behind the mirror of the Melipal telescope PR Photo 16c/04: Colour composite of the star forming region G333.6-0.2 PR Photo 16d/04: Colour composite of the Galactic Centre PR Photo 16e/04: The Ant Planetary Nebula at 12.8 μm PR Photo 16f/04: The starburst galaxy He2-10 at 11.3μm PR Photo 16g/04: High-resolution spectrum of G333.6-0.2 around 12.8μm PR Photo 16h/04: High-resolution spectrum of the Ant Planetary Nebula around 12.8μm From cometary tails to centres of galaxies The mid-infrared spectral region extends from a few to a few tens of microns in wavelength and provides a unique view of our Universe. Optical astronomy, that is astronomy at wavelengths to which our eyes are sensitive, is mostly directed towards light emitted by gas, be it in stars, nebulae or galaxies. Mid-Infrared astronomy, however, allows us to also detect solid dust particles at temperatures of -200 to +300 °C. Dust is very abundant in the universe in many different environments, ranging from cometary tails to the centres of galaxies. This dust also often totally absorbs and hence blocks the visible light reaching us from such objects. Red light, and especially infrared light, can propagate much better in dust clouds. Many important astrophysical processes occur in regions of high obscuration by dust, most notably star formation and the late stages of their evolution, when stars that have burnt nearly all their fuel shed much of their outer layers and dust grains form in their "stellar wind". Stars are born in so-called molecular clouds. The proto-stars feed from these clouds and are shielded from the outside by them. Infrared is a tool - very much as ultrasound is for medical inspections - for looking into those otherwise hidden regions to study the stellar "embryos". It is thus crucial to also observe the Universe in the infrared and mid-infrared. Unfortunately, there are also infrared-emitting molecules in the Earth's atmosphere, e.g. water vapour, Nitric Oxides, Ozone, Methane. Because of these gases, the atmosphere is completely opaque at certain wavelengths, except in a few "windows" where the Earth's atmosphere is transparent. Even in these windows, however, the sky and telescope emit radiation in the infrared to an extent that observing in the mid-infrared at night is comparable to trying to do optical astronomy in daytime. Ground-based infrared astronomers have thus become extremely adept at developing special techniques called "chopping' and "nodding" for detecting the extremely faint astronomical signals against this unwanted bright background [3]. VISIR: an extremely complex instrument VISIR - the VLT Imager and Spectrometer in the InfraRed - is a complex multi-mode instrument designed to operate in the 10 and 20 μm atmospheric windows, i.e. at wavelengths up to about 40 times longer than visible light and to provide images as well as spectra at a wide range of resolving power up to ~ 30.000. It can sample images down to the diffraction limit of the 8.2-m Melipal telescope (0.27 arcsec at 10 μm wavelength, i.e. corresponding to a resolution of 500 m on the Moon), which is expected to be reached routinely due to the excellent seeing conditions experienced for a large fraction of the time at the VLT [2]. Because at room temperature the metal and glass of VISIR would emit strongly at exactly the same wavelengths and would swamp any faint mid-infrared astronomical signals, the whole VISIR instrument is cooled to a temperature close to -250° C and its two panoramic 256x256 pixel array detectors to even lower temperatures, only a few degrees above absolute zero. It is also kept in a vacuum tank to avoid the unavoidable condensation of water and icing which would otherwise occur. The complete instrument is mounted on the telescope and must remain rigid to within a few thousandths of a millimetre as the telescope moves to acquire and then track objects anywhere in the sky. Needless to say, this makes for an extremely complex instrument and explains the many years needed to develop and bring it to the telescope on the top of Paranal. VISIR also includes a number of important technological innovations, most notably its unique cryogenic motor drive systems comprising integrated stepper motors, gears and clutches whose shape is similar to that of the box of the famous French Camembert cheese. VISIR is mounted on Melipal ESO PR Photo 16a/04 ESO PR Photo 16a/04 VISIR under the Cassegrain focus of the Melipal telescope [Preview - JPEG: 400 x 476 pix - 271k] [Normal - JPEG: 800 x 951 pix - 600k] ESO PR Photo 16b/04 ESO PR Photo 16b/04 VISIR mounted behind the mirror of the Melipal telescope [Preview - JPEG: 400 x 603 pix - 366k] [Normal - JPEG: 800 x 1206 pix - 945k] Caption: ESO PR Photo 16a/04 shows VISIR about to be attached at the Cassegrain focus of the Melipal telescope. On ESO PR Photo 16b/04, VISIR appears much smaller once mounted behind the enormous 8.2-m diameter mirror of the Melipal telescope. The fully integrated VISIR plus all the associated equipment (amounting to a total of around 8 tons) was air freighted from Paris to Santiago de Chile and arrived at the Paranal Observatory on 25th March after a subsequent 1500 km journey by road. Following tests to confirm that nothing had been damaged, VISIR was mounted on the third VLT telescope "Melipal" on April 27th. PR Photos 16a/04 and 16b/04 show the approximately 1.6 tons of VISIR being mounted at the Cassegrain focus, below the 8.2-m main mirror. First technical light on a star was achieved on April 29th, shortly after VISIR had been cooled down to its operating temperature. This allowed to proceed with the necessary first basic operations, including focusing the telescope, and tests. While telescope focusing was one of the difficult and frequent tasks faced by astronomers in the past, this is no longer so with the active optics feature of the VLT telescopes which, in principle, has to be focused only once after which it will forever be automatically kept in perfect focus. First images and spectra from VISIR ESO PR Photo 16c/04 ESO PR Photo 16c/04 Colour composite of the star forming region G333.6-0.2 [Preview - JPEG: 400 x 477 pix - 78k] [Normal - JPEG: 800 x 954 pix - 191k] ESO PR Photo 16d/04 ESO PR Photo 16d/04 Colour composite of the Galactic Centre [Preview - JPEG: 400 x 478 pix - 159k] [Normal - JPEG: 800 x 955 pix - 348k] Caption: ESO PR Photo 16c/04 is a colour composite image of the visually obscured G333.6-0.2 star-forming region at a distance of nearly 10,000 light-years in our Milky Way galaxy. This image was made by combining three digital images of the intensity of the infrared emission at wavelengths of 11.3μm (one of the Polycyclic Aromatic Hydrocarbon features, coded blue), 12.8 μm (an emission line of [NeII], coded green) and 19μm (warm dust emission, coded red). Each pixel subtends 0.127 arcsec and the total field is ~ 33 x 33 arcsec with North at the top and East to the left. The total integration times were 13 seconds at the shortest and 35 seconds at the longer wavelengths. The brighter spots locate regions where the dust, which obscures all the visible light, has been heated by recently formed stars. ESO PR Photo 16d/04 shows another colour composite, this time of the Galactic Centre at a distance of about 30,000 light-years. It was made by combining images in filters centred at 8.6μm (Polycyclic Aromatic Hydrocarbon molecular feature - coded blue), 12.8μm ([NeII] - coded green) and 19.5μm (coded red). Each pixel subtends 0.127 arcsec and the total field is ~ 33 x 33 arcsec with North at the top and East to the left. Total integration times were 300, 160 and 300 s for the 3 filters, respectively. This region is very rich, full of stars, dust, ionised and molecular gas. One of the scientific goals will be to detect and monitor the signal from the black hole at the centre of our galaxy. ESO PR Photo 16e/04 ESO PR Photo 16e/04 The Ant Planetary Nebula at 12.8 μm [Preview - JPEG: 400 x 477 pix - 77k] [Normal - JPEG: 800 x 954 pix - 182k] Caption: ESO PR Photo 16e/04 is an image of the "Ant" Planetary Nebula (Mz3) in the narrow-band filter centred at wavelength 12.8 μm. The scale is 0.127 arcsec/pixel and the total field-of-view is 33 x 33 arcsec, with North at the top and East to the left. The total integration time was 200 seconds. Note the diffraction rings around the central star which confirm that the maximum spatial resolution possible with the 8.2-m telescope is being achieved. ESO PR Photo 16f/04 ESO PR Photo 16f/04 The starburst galaxy He2-10 at 11.3μm [Preview - JPEG: 400 x 477 pix - 69k] [Normal - JPEG: 800 x 954 pix - 172k] Caption: ESO PR Photo 16f/04 is an image at wavelength 11.3 μm of the "nearby" (distance about 30 million light-years) blue compact galaxy He2-10, which is actively forming stars. The scale is 0.127 arcsec per pixel and the full field covers 15 x 15 arcsec with North at the top and East on the left. The total integration time for this observation is one hour. Several star forming regions are detected, as well as a diffuse emission, which was unknown until these VISIR observations. The star-forming regions on the left of the image are not visible in optical images. ESO PR Photo 16g/04 ESO PR Photo 16g/04 High-resolution spectrum of G333.6-0.2 around 12.8 μm [Preview - JPEG: 652 x 400 pix - 123k] [Normal - JPEG: 1303 x 800 pix - 277k] Caption: ESO PR Photo 16g/04 is a reproduction of a high-resolution spectrum of the Ne II line (ionised Neon) at 12.8135 μm of the star-forming region G333.6-0.2 shown in ESO PR Photo 16c/04. This spectrum reveals the complex motions of the ionized gas in this region. The images are 256 x 256 frames of 50 x 50 micron pixels. The "field" direction is horizontal, with total slit length of 32.5 arcsec; North is left and South is to the right. The dispersion direction is vertical, with the wavelength increasing downward. The total integration time was 80 sec. ESO PR Photo 16h/04 ESO PR Photo 16h/04 High-resolution spectrum of the Ant nebula around 12.8 μm [Preview - JPEG: 610 x 400 pix - 354k] [Normal - JPEG: 1219 x 800 pix - 901k] Caption: ESO PR Photo 16h/04 is a reproduction of a high-resolution spectrum of the Ne II line (ionised Neon) at 12.8135 microns of the Ant Planetary Nebula, also known as Mz-3, shown in ESO PR Photo 16d/04. The technical details are similar to ESO PR Photo 16g/04. The total integration time was 120 sec. The photos above resulted from some of the first observational tests with VISIR. PR Photo 16c/04 shows the scientific "First Light" image, obtained one day later on April 30th, of a visually obscured star forming region nearly 10,000 light-years away in our galaxy, the Milky Way. The picture shown here is a false-colour image made by combining three digital images of the intensity of the infrared emission from this region at wavelengths of 11.3 μm (one of the Polycyclic Aromatic Hydrocarbon - PAH - features), 12.8 μm (an emission line of ionised neon) and 19 μm (cool dust emission). Ten times sharper Until now, an elegant way to avoid the problems caused by the emission and absorption of the atmosphere was to fly infrared telescopes on satellites as was done in the highly successful IRAS and ISO missions and currently the Spitzer observatory. For both technical and cost reasons, however, such telescopes have so far been limited to only 60-85 cm in diameter. While very sensitive therefore, the spatial resolution (sharpness) delivered by these telescopes is 10 times worse than that of the 8.2-m diameter VLT telescopes. They have also not been equipped with the very high spectral resolution capability, a feature of the VISIR instrument, which is thus expected to remain the instrument of choice for a wide range of studies for many years to come despite the competition from space. More information A corresponding [1]: The consortium of institutes responsible for building the VISIR instrument under contract to ESO comprises the CEA/DSM/DAPNIA, Saclay, France - led by the Principal Investigator (PI), Pierre-Olivier Lagage and the Netherlands Foundation for Research in Astronomy/ASTRON - (Dwingeloo, The Netherlands) with Jan-Willem Pel from Groningen University as Co-PI for the spectrometer. [2]: Stellar radiation on its way to the observer is also affected by the turbulence of the Earth's atmosphere. This is the effect which makes the stars twinkle for the human eye. While the general public enjoys this phenomenon as something that makes the night sky interesting and may be entertaining, the twinkling is a major concern for amateur and professional astronomers, as it smears out the optical images. Infrared radiation is less affected by this effect. Therefore an instrument like VISIR can make full use of the extremely high optical quality of modern telescopes, like the VLT. [3]: Observations from the ground at wavelengths of 10 to 20 μm are particularly difficult because this is the wavelength region in which both the telescope and the atmosphere emits most strongly. In order to minimize its effect, the images shown here were made by tilting the telescope secondary mirror every few seconds (chopping) and the whole telescope every minute (nodding) so that this unwanted telescope and sky background emission could be measured and subtracted from the science images faster than it varies.

External beam pixe programs at the University of California, Davis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eldred, R.A.

A PIXE system in which large or delicate samples are excited by a low-current external proton beam is described. This system has been used to analyze historical printed books and manuscripts, as well as a large variety of archeological artifacts. The steps used to protect the sample from unnecessary beam current are examined. A recent thorough study of the first volume of the Gutenberg 42-line Bible is described in some detail.

The Plasma Interaction Experiment (PIX) description and test program. [electrometers

NASA Technical Reports Server (NTRS)

Ignaczak, L. R.; Haley, F. A.; Domino, E. J.; Culp, D. H.; Shaker, F. J.

1978-01-01

The plasma interaction experiment (PIX) is a battery powered preprogrammed auxiliary payload on the LANDSAT-C launch. This experiment is part of a larger program to investigate space plasma interactions with spacecraft surfaces and components. The varying plasma densities encountered during available telemetry coverage periods are deemed sufficient to determine first order interactions between the space plasma environment and the biased experimental surfaces. The specific objectives of the PIX flight experiment are to measure the plasma coupling current and the negative voltage breakdown characteristics of a solar array segment and a gold plated steel disk. Measurements will be made over a range of surface voltages up to plus or minus kilovolt. The orbital environment will provide a range of plasma densities. The experimental surfaces will be voltage biased in a preprogrammed step sequence to optimize the data returned for each plasma region and for the available telemetry coverage.

Integrated bio-photonics to revolutionize health care enabled through PIX4life and PIXAPP

NASA Astrophysics Data System (ADS)

Jans, Hilde; O'Brien, Peter; Artundo, Iñigo; Porcel, Marco A. G.; Hoofman, Romano; Geuzebroek, Douwe; Dumon, Pieter; van der Vliet, Marcel; Witzens, Jeremy; Bourguignon, Eric; Van Dorpe, Pol; Lagae, Liesbet

2018-02-01

Photonics has become critical to life sciences. However, the field is far from benefiting fully from photonics' capabilities. Today, bulky and expensive optical systems dominate biomedical photonics, even though robust optical functionality can be realized cost-effectively on single photonic integrated circuits (PICs). Such chips are commercially available mostly for telecom applications, and at infrared wavelengths. Although proof-of-concept demonstrations for PICs in life sciences, using visible wavelengths are abundant, the gating factor for wider adoption is limited in resource capacity. Two European pilot lines, PIX4life and PIXAPP, were established to facilitate European R and D in biophotonics, by helping European companies and universities bridge the gap between research and industrial development. Through creation of an open-access model, PIX4life aims to lower barriers to entry for prototyping and validating biophotonics concepts for larger scale production. In addition, PIXAPP enables the assembly and packaging of photonic integrated circuits.

Some new results of PIXE study on Chinese ancient porcelain

NASA Astrophysics Data System (ADS)

Cheng, H. S.; Zhang, B.; Zhu, D.; Yang, F. J.; Sun, X. M.; Guo, M. S.

2005-10-01

This paper reports some new results obtained by PIXE on Chinese ancient porcelain. The first results concern the provenance of blue and white porcelain made during the Tang Dynasty (AD618-907), which are the earliest products found in China. The PIXE experimental results show that they were fired in Huangye Kiln, Gongyi, Henan Province. The chemical composition of the body, white glaze and of the cobalt pigment will be reported. This paper also reports the results for early Chinese blue and white porcelain made under the Yuan dynasty (AD1206-1368) in Jingdezhen, Jiangxi Province. Experimental results show that the chemical composition of the cobalt pigment used by officers and popular are similar. These materials were imported from another country. The local asbolite was used as cobalt pigment material since the early Ming Dynasty (AD1368-1644) in Jingdezhen at folk kiln, and it was used at official kiln until the 16th century.

Use of PIXE-PIGE under variable incident angle for ancient glass corrosion measurements

NASA Astrophysics Data System (ADS)

Weber, G.; Strivay, D.; Martinot, L.; Garnir, H. P.

2002-04-01

Although glass is usually considered as a very stable archaeological material, it can undergo severe degradation. Soda-lime glass, the most common glass throughout ancient times, is particularly sensitive to this problem. The glass surface absorbs moisture from its environment and the contact with CO 2 causes Na 2O and NaOH to convert to Na 2CO 3, which is extremely hygroscopic. The subsequent unstable glass layer can be leached out and causes decomposition of the glass. The non-destructive PIGE-PIXE method of investigation allows detection of this phenomenon even if no visible effect appears. The variable incident angle method is able to discern the depth of the degradation. One aim of such studies is the possible dating or at least fake detecting of archaeological materials. Furthermore, even objects of large size can be investigated with the atmospheric PIGE-PIXE set-up. Some examples of measurements on ancient glass are given.

Developments towards the LHCb VELO upgrade

NASA Astrophysics Data System (ADS)

Cid Vidal, Xabier

2016-09-01

The Vertex Locator (VELO) is a silicon strip detector surrounding the interaction region of the LHCb experiment. The upgrade of the VELO is planned to be installed in 2019-2020, and the current detector will be replaced by a hybrid pixel system equipped with electronics capable of reading out at a rate of 40 MHz. The new detector is designed to withstand the radiation dose expected at an integrated luminosity of 50 fb-1. The detector will be composed of silicon pixel sensors, read out by the VeloPix ASIC that is being developed based on the TimePix/MediPix family. The prototype sensors for the VELO upgrade are being irradiated in five different facilities and the post-irradiation performance is being measured with testbeams, and in the lab. These proceedings present the VELO upgrade and briefly discuss the results of the sensor testing campaign.

A Powerful Twin Arrives

NASA Astrophysics Data System (ADS)

1999-11-01

First Images from FORS2 at VLT KUEYEN on Paranal The first, major astronomical instrument to be installed at the ESO Very Large Telescope (VLT) was FORS1 ( FO cal R educer and S pectrograph) in September 1998. Immediately after being attached to the Cassegrain focus of the first 8.2-m Unit Telescope, ANTU , it produced a series of spectacular images, cf. ESO PR 14/98. Many important observations have since been made with this outstanding facility. Now FORS2 , its powerful twin, has been installed at the second VLT Unit Telescope, KUEYEN . It is the fourth major instrument at the VLT after FORS1 , ISAAC and UVES.. The FORS2 Commissioning Team that is busy installing and testing this large and complex instrument reports that "First Light" was successfully achieved already on October 29, 1999, only two days after FORS2 was first mounted at the Cassegrain focus. Since then, various observation modes have been carefully tested, including normal and high-resolution imaging, echelle and multi-object spectroscopy, as well as fast photometry with millisecond time resolution. A number of fine images were obtained during this work, some of which are made available with the present Press Release. The FORS instruments ESO PR Photo 40a/99 ESO PR Photo 40a/99 [Preview - JPEG: 400 x 345 pix - 203k] [Normal - JPEG: 800 x 689 pix - 563kb] [Full-Res - JPEG: 1280 x 1103 pix - 666kb] Caption to PR Photo 40a/99: This digital photo shows the twin instruments, FORS2 at KUEYEN (in the foreground) and FORS1 at ANTU, seen in the background through the open ventilation doors in the two telescope enclosures. Although they look alike, the two instruments have specific functions, as described in the text. FORS1 and FORS2 are the products of one of the most thorough and advanced technological studies ever made of a ground-based astronomical instrument. They have been specifically designed to investigate the faintest and most remote objects in the universe. They are "multi-mode instruments" that may be used in several different observation modes. FORS2 is largely identical to FORS1 , but there are a number of important differences. For example, it contains a Mask Exchange Unit (MXU) for laser-cut star-plates [1] that may be inserted at the focus, allowing a large number of spectra of different objects, in practice up to about 70, to be taken simultaneously. Highly sophisticated software assigns slits to individual objects in an optimal way, ensuring a great degree of observing efficiency. Instead of the polarimetry optics found in FORS1 , FORS2 has new grisms that allow the use of higher spectral resolutions. The FORS project was carried out under ESO contract by a consortium of three German astronomical institutes, the Heidelberg State Observatory and the University Observatories of Göttingen and Munich. The participating institutes have invested a total of about 180 man-years of work in this unique programme. The photos below demonstrate some of the impressive possibilities with this new instrument. They are based on observations with the FORS2 standard resolution collimator (field size 6.8 x 6.8 armin = 2048 x 2048 pixels; 1 pixel = 0.20 arcsec). In addition, observations of the Crab pulsar demonstrate a new observing mode, high-speed photometry. Protostar HH-34 in Orion ESO PR Photo 40b/99 ESO PR Photo 40b/99 [Preview - JPEG: 400 x 444 pix - 220kb] [Normal - JPEG: 800 x 887 pix - 806kb] [Full-Res - JPEG: 2000 x 2217 pix - 3.6Mb] The Area around HH-34 in Orion ESO PR Photo 40c/99 ESO PR Photo 40c/99 [Preview - JPEG: 400 x 494 pix - 262kb] [Full-Res - JPEG: 802 x 991 pix - 760 kb] The HH-34 Superjet in Orion (centre) PR Photo 40b/99 shows a three-colour composite of the young object Herbig-Haro 34 (HH-34) , now in the protostar stage of evolution. It is based on CCD frames obtained with the FORS2 instrument in imaging mode, on November 2 and 6, 1999. This object has a remarkable, very complicated appearance that includes two opposite jets that ram into the surrounding interstellar matter. This structure is produced by a machine-gun-like blast of "bullets" of dense gas ejected from the star at high velocities (approaching 250 km/sec). This seems to indicate that the star experiences episodic "outbursts" when large chunks of material fall onto it from a surrounding disk. HH-34 is located at a distance of approx. 1,500 light-years, near the famous Orion Nebula , one of the most productive star birth regions. Note also the enigmatic "waterfall" to the upper left, a feature that is still unexplained. PR Photo 40c/99 is an enlargement of a smaller area around the central object. Technical information : Photo 40b/99 is based on a composite of three images taken through three different filters: B (wavelength 429 nm; Full-Width-Half-Maximum (FWHM) 88 nm; exposure time 10 min; here rendered as blue), H-alpha (centered on the hydrogen emission line at wavelength 656 nm; FWHM 6 nm; 30 min; green) and S II (centrered at the emission lines of inonized sulphur at wavelength 673 nm; FWHM 6 nm; 30 min; red) during a period of 0.8 arcsec seeing. The field shown measures 6.8 x 6.8 arcmin and the images were recorded in frames of 2048 x 2048 pixels, each measuring 0.2 arcsec. The Full Resolution version shows the original pixels. North is up; East is left. N 70 Nebula in the Large Magellanic Cloud ESO PR Photo 40d/99 ESO PR Photo 40d/99 [Preview - JPEG: 400 x 444 pix - 360kb] [Normal - JPEG: 800 x 887 pix - 1.0Mb] [Full-Res - JPEG: 1997 x 2213 pix - 3.4Mb] The N 70 Nebula in the LMC ESO PR Photo 40e/99 ESO PR Photo 40e/99 [Preview - JPEG: 400 x 485 pix - 346kb] [Full-Res - JPEG: 986 x 1196 pix - 1.2Mb] The N70 Nebula in the LMC (detail) PR Photo 40d/99 shows a three-colour composite of the N 70 nebula. It is a "Super Bubble" in the Large Magellanic Cloud (LMC) , a satellite galaxy to the Milky Way system, located in the southern sky at a distance of about 160,000 light-years. This photo is based on CCD frames obtained with the FORS2 instrument in imaging mode in the morning of November 5, 1999. N 70 is a luminous bubble of interstellar gas, measuring about 300 light-years in diameter. It was created by winds from hot, massive stars and supernova explosions and the interior is filled with tenuous, hot expanding gas. An object like N70 provides astronomers with an excellent opportunity to explore the connection between the lifecycles of stars and the evolution of galaxies. Very massive stars profoundly affect their environment. They stir and mix the interstellar clouds of gas and dust, and they leave their mark in the compositions and locations of future generations of stars and star systems. PR Photo 40e/99 is an enlargement of a smaller area of this nebula. Technical information : Photos 40d/99 is based on a composite of three images taken through three different filters: B (429 nm; FWHM 88 nm; 3 min; here rendered as blue), V (554 nm; FWHM 111 nm; 3 min; green) and H-alpha (656 nm; FWHM 6 nm; 3 min; red) during a period of 1.0 arcsec seeing. The field shown measures 6.8 x 6.8 arcmin and the images were recorded in frames of 2048 x 2048 pixels, each measuring 0.2 arcsec. The Full Resolution version shows the original pixels. North is up; East is left. The Crab Nebula in Taurus ESO PR Photo 40f/99 ESO PR Photo 40f/99 [Preview - JPEG: 400 x 446 pix - 262k] [Normal - JPEG: 800 x 892 pix - 839 kb] [Full-Res - JPEG: 2036 x 2269 pix - 3.6Mb] The Crab Nebula in Taurus ESO PR Photo 40g/99 ESO PR Photo 40g/99 [Preview - JPEG: 400 x 444 pix - 215kb] [Full-Res - JPEG: 817 x 907 pix - 485 kb] The Crab Nebula in Taurus (detail) PR Photo 40f/99 shows a three colour composite of the well-known Crab Nebula (also known as "Messier 1" ), as observed with the FORS2 instrument in imaging mode in the morning of November 10, 1999. It is the remnant of a supernova explosion at a distance of about 6,000 light-years, observed almost 1000 years ago, in the year 1054. It contains a neutron star near its center that spins 30 times per second around its axis (see below). PR Photo 40g/99 is an enlargement of a smaller area. More information on the Crab Nebula and its pulsar is available on the web, e.g. at a dedicated website for Messier objects. In this picture, the green light is predominantly produced by hydrogen emission from material ejected by the star that exploded. The blue light is predominantly emitted by very high-energy ("relativistic") electrons that spiral in a large-scale magnetic field (so-called syncrotron emission ). It is believed that these electrons are continuously accelerated and ejected by the rapidly spinning neutron star at the centre of the nebula and which is the remnant core of the exploded star. This pulsar has been identified with the lower/right of the two close stars near the geometric center of the nebula, immediately left of the small arc-like feature, best seen in PR Photo 40g/99 . Technical information : Photo 40f/99 is based on a composite of three images taken through three different optical filters: B (429 nm; FWHM 88 nm; 5 min; here rendered as blue), R (657 nm; FWHM 150 nm; 1 min; green) and S II (673 nm; FWHM 6 nm; 5 min; red) during periods of 0.65 arcsec (R, S II) and 0.80 (B) seeing, respectively. The field shown measures 6.8 x 6.8 arcmin and the images were recorded in frames of 2048 x 2048 pixels, each measuring 0.2 arcsec. The Full Resolution version shows the original pixels. North is up; East is left. The High Time Resolution mode (HIT) of FORS2 ESO PR Photo 40h/99 ESO PR Photo 40h/99 [Preview - JPEG: 400 x 304 pix - 90kb] [Normal - JPEG: 707 x 538 pix - 217kb] Time Sequence of the Pulsar in the Crab Nebula ESO PR Photo 40i/99 ESO PR Photo 40i/99 [Preview - JPEG: 400 x 324 pix - 42kb] [Normal - JPEG: 800 x 647 pix - 87kb] Lightcurve of the Pulsar in the Crab Nebula In combination with the large light collecting power of the VLT Unit Telescopes, the high time resolution (25 nsec = 0.000000025 sec) of the ESO-developed FIERA CCD-detector controller opens a new observing window for celestial objects that undergo light intensity variations on very short time scales. A first implementation of this type of observing mode was tested with FORS2 during the first commissioning phase, by means of one of the most fascinating astronomical objects, the rapidly spinning neutron star in the Crab Nebula . It is also known as the Crab pulsar and is an exceedingly dense object that represents an extreme state of matter - it weighs as much as the Sun, but measures only about 30 km across. The result presented here was obtained in the so-called trailing mode , during which one of the rectangular openings of the Multi-Object Spectroscopy (MOS) assembly within FORS2 is placed in front of the lower end of the field. In this way, the entire surface of the CCD is covered, except the opening in which the object under investigation is positioned. By rotating this opening, some neighbouring objects (e.g. stars for alignment) may be observed simultaneously. As soon as the shutter is opened, the charges on the chip are progressively shifted upwards, one pixel at a time, until those first collected in the bottom row behind the opening have reached the top row. Then the entire CCD is read out and the digital data with the full image is stored in the computer. In this way, successive images (or spectra) of the object are recorded in the same frame, displaying the intensity variation with time during the exposure. For this observation, the total exposure lasted 2.5 seconds. During this time interval the image of the pulsar (and those of some neighbouring stars) were shifted 2048 times over the 2048 rows of the CCD. Each individual exposure therefore lasted exactly 1.2 msec (0.0012 sec), corresponding to a nominal time-resolution of 2.4 msec (2 pixels). Faster or slower time resolutions are possible by increasing or decreasing the shift and read-out rate [2]. In ESO PR Photo 40h/99 , the continuous lines in the top and bottom half are produced by normal stars of constant brightness, while the series of dots represents the individual pulses of the Crab pulsar, one every 33 milliseconds (i.e. the neutron star rotates around its axis 30 times per second). It is also obvious that these dots are alternatively brighter and fainter: they mirror the double-peaked profile of the light pulses, as shown in ESO PR Photo 40i/99 . In this diagramme, the time increases along the abscissa axis (1 pixel = 1.2 msec) and the momentary intensity (uncalibrated) is along the ordinate axis. One full revolution of the neutron star corresponds to the distance from one high peak to the next, and the diagramme therefore covers six consecutive revolutions (about 200 milliseconds). Following thorough testing, this new observing mode will allow to investigate the brightness variations of this and many other objects in great detail in order to gain new and fundamental insights in the physical mechanisms that produce the radiation pulses. In addition, it is foreseen to do high time resolution spectroscopy of rapidly varying phenomena. Pushing it to the limits with an 8.2-m telescope like KUEYEN will be a real challenge to the observers that will most certainly lead to great and exciting research projects in various fields of modern astrophysics. Technical information : The frame shown in Photo 40h/99 was obtained during a total exposure time of 2.5 sec without any optical filtre. During this time, the charges on the CCD were shifted over 2048 rows; each row was therefore exposed during 1.2 msec. The bright continuous line comes from the star next to the pulsar; the orientation was such that the "observation slit" was placed over two neighbouring stars. Preliminary data reduction: 11 pixels were added across the pulsar image to increase the signal-to-noise ratio and the background light from the Crab Nebula was subtracted for the same reason. Division by a brighter star (also background-subtracted, but not shown in the image) helped to reduce the influence of the Earth's atmosphere. Notes [1] The masks are produced by the Mask Manufacturing Unit (MMU) built by the VIRMOS Consortium for the VIMOS and NIRMOS instruments that will be installed at the VLT MELIPAL and YEPUN telescopes, respectively. [2] The time resolution achieved during the present test was limited by the maximum charge transfer rate of this particular CCD chip; in the future, FORS2 may be equipped with a new chip with a rate that is up to 20 times faster. How to obtain ESO Press Information ESO Press Information is made available on the World-Wide Web (URL: http://www.eso.org../ ). ESO Press Photos may be reproduced, if credit is given to the European Southern Observatory.

Micro-PIXE analysis of silicate reference standards

USGS Publications Warehouse

Czamanske, G.K.; Sisson, T.W.; Campbell, J.L.; Teesdale, W.J.

1993-01-01

The accuracy and precision of the University of Guelph proton microprobe have been evaluated through trace-element analysis of well-characterized silicate glasses and minerals, including BHVO-1 glass, Kakanui augite and hornblende, and ten other natural samples of volcanic glass, amphibole, pyroxene, and garnet. Using the 2.39 wt% Mo in a NIST steel as the standard, excellent precision and agreement between reported and analyzed abundances were obtained for Fe, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, and Nb. -from Authors

Spatially resolved elemental distributions in articular cartilage

NASA Astrophysics Data System (ADS)

Reinert, T.; Reibetanz, U.; Vogt, J.; Butz, T.; Werner, A.; Gründer, W.

2001-07-01

In this study, the nuclear microprobe technique is employed to analyse the chemistry of joint cartilage in order to correlate internal structures of the collagen network with the elemental distribution. The samples were taken from pig's knee joint. 30 μm thick coronar cross-sections were prepared by means of cryosectioning and freeze-drying. We performed simultaneously particle induced X-ray emission (PIXE), Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA). Thus we obtained spatially resolved distributions of the elements H, C, N, O, P, S, Cl, K and Ca. The main components of the organic matrix are H, C, N and O. It was shown that their relations vary with the cartilage structures. It could be shown that zones with aligned collagen fibrils contain less sulphur and potassium but more chlorine. The higher chlorine concentration is remarkable because newest biochemical studies found that hypochloric acid is involved in cartilage degradation. Furthermore, the calcium distribution is still of great interest. Its correlation to structural changes inside the cartilage is still being discussed. It could be disproved that zones of higher calcium concentration are related to the aligned structures of the collagen network.

Laser-deposited thin films of biocompatible ceramic

NASA Astrophysics Data System (ADS)

Jelinek, Miroslav; Olsan, V.; Jastrabik, Lubomir; Dostalova, Tatjana; Himmlova, Lucia; Kadlec, Jaromir; Pospichal, M.; Simeckova, M.; Fotakis, Costas

1995-03-01

Thin films of biocompatible materials such as hydroxylapatite (HA) - Ca10 (PO4)6(OH)2 were deposited by laser ablation technique. The films of HA were created on Ti substrates by KrF laser. The layers were deposited in vacuum, in pure H2O vapors (pressure 2 X 10-3 mbar - 2 X 10-1 mbar), and in Ar/H2O vapor mixture. Influence of laser energy density ET (3 Jcm-2, 13 Jcm-2) and substrate temperature Tg (500 degree(s)C - 760 degree(s)C) on the film parameters was studied. Two different technological processes were used for HA target preparation. Films and targets were characterized by Rutherford backscattering analysis (RBS), particle induced x-ray emission (PIXE), x-ray diffraction (XRD), scanning electron microscopy (SEM) and by Knoop microhardness and scratch test. The best crystalline HA films were reached in the mixture of Ar/H2O. Higher Tg had to be used for such deposition. Higher Tg was also preferable from the point of film microhardness. Adhesion of films to the substrates in the range of tens of Newtons was measured. The preliminary results of in vitro experiments of films biotolerance and resorbability are also presented.

Proton Induced X-ray Emission Spectroscopy of Red Wine Samples Using the Union College Pelletron Accelerator

NASA Astrophysics Data System (ADS)

Schuff, Katie; Labrake, Scott

2010-11-01

A 1-megavolt tandem electrostatic Pelletron particle accelerator housed at Union College was used to measure the elemental composition and concentration of homemade Cabernet and Merlot red wine samples. A beam of 1.8-MeV protons directed at an approximately 12-μm thin Mylar substrate onto which 8-μL of concentrated red wine was dried caused inner shell electrons to be ejected from the target nuclei and these vacancies are filled through electronic transitions of higher orbital electrons accompanied by the production of an x-ray photon characteristic of the elemental composition of the target. This is the PIXE Method. Data on the intensity versus energy of the x-rays were collected using an Amptek silicon drift detector and were analyzed to determine the elemental composition and the samples were found to contain P, S, K, Cl, Ca, Sc, Mn, Al, Fe, & Co. Elemental concentrations were determined using the analysis package GUPIX. It is hypothesized that the cobalt seen is a direct result of the uptake by the grapes and as a product of the fermentation process a complex of vitamin B12 is produced.

Determination of Se in soil samples using the proton induced X-ray emission technique

NASA Astrophysics Data System (ADS)

Cruvinel, Paulo E.; Flocchini, Robert G.

1993-04-01

An alternative method for the direct determination of total Se in soil samples is presented. A large number of trace elements is present in soil at concentration values in the range of part per billion and tenths of parts of million. The most common are the trace elements of Al, Si, K, Ca, Ti, V, Cr, Fe, Cu, Zn, Br, Rb, Mo, Cd and Pb. As for biological samples many of these elements are of great importance for the nutrition of plants, while others are toxic and others have an unknown role. Selenium is an essential micronutrient for humans and animals but it is also known that in certain areas Se deficiency or toxicity has caused endemic disease to livestock and humans through the soil-plant-animal linkage. In this work the suitability of the proton induced X-ray emission (PIXE) technique as a fast and nondestructive technique useful to measure total the Se content in soil samples is demonstrated. To validate the results a comparison of data collected using the conventional atomic absorption spectrophotometry (AAS) method was performed.

Exposure to PM2.5 in modern office buildings through elemental characterization and oxidative potential

NASA Astrophysics Data System (ADS)

Szigeti, Tamás; Kertész, Zsófia; Dunster, Christina; Kelly, Frank J.; Záray, Gyula; Mihucz, Victor G.

2014-09-01

Fifty samples of indoor and outdoor PM2.5 were collected onto quartz fiber and Teflon membrane filters in five office buildings equipped with heating, ventilation and air-conditioning system for 8 h daily in order to coincide with the work shift of employees. Samples were analyzed for i) mass concentration; ii) elemental concentration; and iii) oxidative potential (OP) through antioxidant depletion. The PM2.5 mass concentration exceeded the annual mean guideline of 10 μg m-3 WHO in 50% of the samples. Indoor and outdoor PM2.5 mass concentrations correlated almost linearly. Proton-induced X-ray emission (PIXE) spectrometry was used for the monitoring of 21 elements. Quantitative determination was achieved in the case of Teflon filters only for Al, Si, S, Cl, K, Ca, Ti, Cr, Mn, Fe and Zn at ng m-3 concentration level. Quartz fiber filters were less adequate for the PIXE measurements due to their greater thickness and filamentary structure. Ca, Cr, Zn and Ti had generally higher concentration (mg g-1) indoors. Indoor/outdoor (I/O) OP values were higher than one in 14% and 57% of the samples in the case of ascorbate and reduced glutathione (GSH), respectively. Spatial and temporal variations of OP were observed across the office buildings. The I/O ratios for OP, Cr and Zn concentrations in the case of GSH were higher for three buildings. Significant relationship was observed between GSH oxidation and Cr and Zn concentrations. Thus, employees were exposed to a higher extent to reactive oxygen species in three buildings.

Catching a Falling Star

NASA Astrophysics Data System (ADS)

2004-07-01

ESO's Very Large Telescope Obtains Unique Spectrum of a Meteor Summary While observing a supernova in a distant galaxy with the FORS instrument on ESO's Very Large Telescope at the Paranal Observatory (Chile), astronomers were incredibly lucky to obtain serendipitously a high quality spectrum of a very large meteor in the terrestrial atmosphere. The VLT spectrograph provided a well calibrated spectrum, making it a reference in this field of research. From this spectrum, the temperature of the meteor trail was estimated to be about 4600 degrees centigrade. The serendipitous spectrum reveals the telltale meteor emissions of oxygen and nitrogen atoms and nitrogen molecules. The VLT spectrum was the first to reveal the far red range where carbon emission lines are predicted; the absence of the lines puts constraints on the role of atmospheric chemistry when life started on earth. Because the VLT is tuned to observe objects far out in space, it focuses at infinity. The meteor, being "only" 100 km above the telescope, therefore appears out of focus in the field of view. PR Photo 22a/04: Meteor Caught in the Act (MASCOT) PR Photo 22b/04: Spectrum of a Meteor (FORS1/VLT) PR Photo 22c/04: Details of the Meteor Spectrum (FORS1/VLT) Astronomers' luck ESO PR Photo 22a/04 ESO PR Photo 22a/04 Meteor Caught in the Act (MASCOT) [Preview - JPEG: 426 x 400 pix - 85k] [Normal - JPEG: 851 x 800 pix - 187k] [Full Res - JPEG: 2567 x 2413 pix - 908k] Captions: ESO PR Photo 22a/04 shows the trail of a bright meteor, photographed by the Mini All-Sky Cloud Observation Tool (MASCOT) at the ESO Paranal Observatory. MASCOT consists of a small CCD camera behind a fish-eye objective. It typically takes 90s exposures every 3 minutes and helps astronomers inside the VLT Control Room to keep an eye on the sky. The main purpose of MASCOT is to monitor the clouds over Paranal but it also observes from time to time serendipitous events like meteor showers, atmospheric phenomena, artificial satellites, etc. This image was obtained by MASCOT on August 25, 2002 and shows a meteor caught in the act. (Note that this is not the meteor whose spectrum was recorded). The Milky Way is also clearly visible in the centre. A popular saying states that when you see a meteor, you may make a wish. While astronomers cannot promise that it will be realised, a team of astronomers [1] have indeed seen a dream come true! On May 12, 2002, they were lucky to record the spectrum of a bright meteor when it happened - by sheer chance and against all reasonable odds - to cross the narrow slit of the FORS1 instrument on the ESO Very Large Telescope. At the time of this unlikely event, the telescope was performing a series of 20-minute spectroscopic exposures of a supernova in a distant galaxy in order to establish constraints on the dark energy content of the Universe (see e.g. ESO PR 21/98). Thanks to its enormous light-collecting and magnifying power, the VLT recorded the spectrum of the meteor trail perpendicular to its path on one of these exposures. "We really hit the jackpot", says ESO astronomer Emmanuel Jehin: "Chances of capturing a meteor in the narrow slit of the FORS1 spectrograph are about as big as for me winning the national lottery." Meteor spectra have on occasion been obtained serendipitously during photographic star spectra surveys. But this is now maybe the only meteor spectrum recorded with a large telescope and a modern spectrograph. The spectrum covers the wavelength range from 637 to 1050 nm, which is dominated by emissions from air atoms and molecules in the meteor path and teach us about the collision processes in the wake of a meteoroid. The rapid motion of the meteor across the sky resulted in a very brief exposure while crossing the narrow spectrograph slit - only 1/50 of a millisecond! - and despite the relative brightness of the meteor it was only thanks to the VLT's great light-gathering power that any record was procured. The meteor was estimated at magnitude -8, or nearly as bright as the first-quarter Moon. Although it is not possible to be sure from which shower this meteor belongs, a possible candidate is the Southern May Ophiuchid shower which appears from a direction just east of the bright star Antares. The shower contributes only one or two meteors per hour but was one of the stronger showers of that night. Telltale emissions ESO PR Photo 22b/04 ESO PR Photo 22b/04 Spectrum of a Meteor (FORS1/VLT) [Preview - JPEG: 426 x 400 pix - 91k] [Normal - JPEG: 851 x 800 pix - 232k] [Full Res - JPEG: 2567 x 2413 pix - 2.1M] ESO PR Photo 22c/04 ESO PR Photo 22c/04 Details of the Meteor Spectrum (FORS1/VLT) [Preview - JPEG: 1006 x 400 pix - 122k] [Normal - JPEG: 2011 x 800 pix - 236k] [Full Res - JPEG: 3414 x 1358 pix - 957k] Captions: ESO PR Photo 22b/04 shows the spectrum of a bright meteor, as observed serendipitously by the multi-mode FORS 1 instrument on the ESO Very Large Telescope during the night of May 12-13, 2002, in front of a photo of the VLT enclosures and with a meteor trail inserted in the sky (montage). The position of the meteor trail on the narrow slit of FORS (not to scale) is also indicated. The lower panel shows the spectrum of the meteor, following removal of the supernova spectrum and before (up) and after (down) removal of the spectrum of the night sky by image processing. Several emission lines from colliding Oxygen and Nitrogen atoms (sharp emissions) and molecules (broad emissions) are visible. ESO PR Photo 22c/04 illustrates details of the extracted VLT meteor spectrum (solid line): the intensity (in arbitrary units) is shown as a function of the wavelength. The dashed line is a theoretical model of the spectrum of air heated to a temperature of 4600 degrees at an altitude of 95 km. "At first, the bright trace across the supernova spectrum was a puzzle, but then I realized that the spectroscopic signature was that of our atmosphere being bombarded," says astronomer Remi Cabanac of the Catholic University of Santiago de Chile. "We asked around to see if others in our country had witnessed the meteor, but it seems we at the VLT were the only ones, perhaps not too surprising as Paranal is located in the middle of the empty desert." And unfortunately for the astronomers, the MASCOT all-sky camera (e.g. PR Photo 22a/04) was not yet in operation at that time. The VLT spectrograph provided a well calibrated spectrum of the meteor emission, making it a reference in this field of research. The meteor emission results from collisions between air molecules, knocked to high speeds after initial collision with the meteoroid. Closer inspection of the spectrum revealed about 20 telltale meteor emissions of oxygen and nitrogen atoms and nitrogen molecules (see PR Photo 22b/04 and 22c/04). The ratio of atomic and molecular emissions could be used as a "thermometer" to measure the conditions in the meteor-induced hot gas in the wake of the meteoroid, by means of laboratory measurements and meteor models that calibrate the VLT data. From here to infinity "To our surprise, we found the meteor trail to be wider than expected and also that the meteor's heat appeared evenly distributed in the trail, with the temperature varying only from about 4,570 to 4,650 degrees across the trail," says meteor specialist, astronomer Peter Jenniskens of the SETI Intitute, who analysed the data together with Christophe Laux of the Ecole Centrale Paris (France) and Iain Boyd of the University of Michigan at Ann Arbor (USA). "We later realised that this was due to the fact that, as seen by the VLT, the meteor trail was out of focus, even though it was 100 kilometres away!" The VLT is indeed focussed at infinity, which is perfect for most astronomical objects that it routinely observes. But not for meteoroids entering the atmosphere above Paranal. A point at 100 kilometres distance will appear as a small circle of diameter 15 arcsec at the VLT focal plane. This corresponds to roughly half of the maximum apparent diameter of Mars in the evening sky! It is the same effect as when you try to photograph your children with a forest in the background. If you focus your camera on the distant forest, then (in most cases) your children will be out of focus. Or to put this in another way, the VLT is clearly not very suited to observe ships passing by on the Pacific Ocean, just 12 km from Paranal! No Trace of Carbon The meteor spectrum also provided a first view of such an object in the near-infrared window between wavelengths 900 and 1050 nm. This spectral region contains relatively strong lines of atomic carbon, but no such emissions were detected. "We calculated that these lines should have been visible if all atmospheric carbon dioxide in the meteor path was dissociated into carbon and oxygen atoms," says Jenniskens, "but they were conspicuously absent". This observation is important because it sets new constraints on the efficiency of meteor-induced atmospheric chemistry at the time when life began on our planet. Appendix: Cosmic showers Meteoroids are small grains of rocks orbiting the Sun. Far smaller than asteroids, they make their presence known to us in a dramatic and beautiful way when they enter earth's atmosphere and burn up, producing a short glowing trail in the night sky, rarely lasting more than a second or two - a meteor. Most meteoroids are completely destroyed at altitudes between 80 and 110 km, but some of the bigger ones make it to the ground. Here they may be collected as meteorites. Many meteoroids originate as fragments of asteroids and appear to be unaltered since the formation of the Solar System, some 4500 million years ago. Based on the peculiar composition of some meteorites, we know that a small fraction of meteoroids originate from the Moon, Mars or the large asteroid Vesta. They obviously result from major impacts on these bodies which blasted rock fragments into space. These fragments then orbit the Sun and may eventually collide with the Earth. Comets are another important source of meteoroids and perhaps the most spectacular. After many visits near the Sun, a comet "dirty-snowball" nucleus of ice and dust decays and fragments, leaving a trail of meteoroids along its orbit. Some "meteoroid streams" cross the earth's orbit and when our planet passes through them, some of these particles will enter the atmosphere. The outcome is a meteor shower - the most famous being the "Perseids" in the month of August [2] and the "Leonids" in November. Thus, although meteors are referred to as "shooting" or "falling stars" in many languages, they are of a very different nature. More information The research presented in this paper is published in the journal Meteoritics and Planetary Science, Vol. 39, Nr. 4, p. 1, 2004 ("Spectroscopic anatomy of a meteor trail cross section with the ESO Very Large Telescope", by P. Jenniskens et al.). Notes [1] The team is composed of Peter Jenniskens (SETI Institute, USA), Emmanuël Jehin (ESO), Remi Cabanac (Pontificia Universidad Catolica de Chile), Christophe Laux (Ecole Centrale de Paris, France), and Iain Boyd (University of Michigan, USA). [2] The maximum of the Perseids is expected on August 12 after sunset and should be easily seen.

Accelerator-based chemical and elemental analysis of atmospheric aerosols

NASA Astrophysics Data System (ADS)

Mentes, Besim

Aerosol particles have always been present in the atmosphere, arising from natural sources. But it was not until recently when emissions from anthropogenic (man made) sources began to dominate, that atmospheric aerosols came into focus and the aerosol science in the environmental perspective started to grow. These sources emit or produce particles with different elemental and chemical compositions, as well as different sizes of the individual aerosols. The effects of increased pollution of the atmosphere are many, and have different time scales. One of the effects known today is acid rain, which causes problems for vegetation. Pollution is also a direct human health risk, in many cities where traffic driven by combustion engines is forbidden at certain times when the meteorological conditions are unfavourable. Aerosols play an important role in the climate, and may have both direct and indirect effect which cause cooling of the planet surface, in contrast to the so-called greenhouse gases. During this work a technique for chemical and elemental analysis of atmospheric aerosols and an elemental analysis methodology for upper tropospheric aerosols have been developed. The elemental analysis is performed by the ion beam analysis (IBA) techniques, PIXE (elements heavier than Al). PESA (C, N and O), cPESA (H) and pNRA (Mg and Na). The chemical speciation of atmospheric aerosols is obtained by ion beam thermography (IBT). During thermography the sample temperature is stepwise increased and the IBA techniques are used to continuously monitor the elemental concentration. A thermogram is obtained for each element. The vaporisation of the compounds in the sample appears as a concentration decrease in the thermograms at characteristic vaporisation temperatures (CVTs). Different aspects of IBT have been examined in Paper I to IV. The features of IBT are: almost total elemental speciation of the aerosol mass, chemical speciation of the inorganic compounds, carbon content obtained as volatile and non-volatile fractions, analysis of acidic aerosols is possible, aerosols can be size-fractionated using a cascade impactor as collection device, total analysis time for a sample is around 45 min, the sample mass load is from around 1 to 30 μg/cm2. An intercomparison of IBT and ion chromatography (IC) when a DMPS system was used as a reference instrument has been performed (Paper IV). Ions of K, Na, SO4, NO3 and NH4 were determined and quantified by both IBT and IC. The intercomparison showed that the procedure used in IBT does not suffer from any selective losses, especially not from the NO3 and NH4 compounds, which exhibit an appreciable interaction with the gas phase as NH3 and HNO3. An impactor-based aerosol sampler for upper tropospheric conditions has been developed (Paper V). Despite the low aerosol concentration at that altitude the sulphur concentration can be measured, with a detection limit of 1 ng/m 3 for one hour sampling by optimising parameters in the use of PIXE analysis.

The President and the Galaxy

NASA Astrophysics Data System (ADS)

2004-12-01

On December 9-10, 2004, the ESO Paranal Observatory was honoured with an overnight visit by His Excellency the President of the Republic of Chile, Ricardo Lagos and his wife, Mrs. Luisa Duran de Lagos. The high guests were welcomed by the ESO Director General, Dr. Catherine Cesarsky, ESO's representative in Chile, Mr. Daniel Hofstadt, and Prof. Maria Teresa Ruiz, Head of the Astronomy Department at the Universidad de Chile, as well as numerous ESO staff members working at the VLT site. The visit was characterised as private, and the President spent a considerable time in pleasant company with the Paranal staff, talking with and getting explanations from everybody. The distinguished visitors were shown the various high-tech installations at the observatory, including the Interferometric Tunnel with the VLTI delay lines and the first Auxiliary Telescope. Explanations were given by ESO astronomers and engineers and the President, a keen amateur astronomer, gained a good impression of the wide range of exciting research programmes that are carried out with the VLT. President Lagos showed a deep interest and impressed everyone present with many, highly relevant questions. Having enjoyed the spectacular sunset over the Pacific Ocean from the Residence terrace, the President met informally with the Paranal employees who had gathered for this unique occasion. Later, President Lagos visited the VLT Control Room from where the four 8.2-m Unit Telescopes and the VLT Interferometer (VLTI) are operated. Here, the President took part in an observing sequence of the spiral galaxy NGC 1097 (see PR Photo 35d/04) from the console of the MELIPAL telescope. After one more visit to the telescope platform at the top of Paranal, the President and his wife left the Observatory in the morning of December 10, 2004, flying back to Santiago. ESO PR Photo 35e/04 ESO PR Photo 35e/04 President Lagos Meets with ESO Staff at the Paranal Residencia [Preview - JPEG: 400 x 267pix - 144k] [Normal - JPEG: 640 x 427 pix - 240k] ESO PR Photo 35f/04 ESO PR Photo 35f/04 The Presidential Couple with Professor Maria Teresa Ruiz and the ESO Director General [Preview - JPEG: 500 x 400 pix - 224k] [Normal - JPEG: 1000 x 800 pix - 656k] [FullRes - JPEG: 1575 x 1260 pix - 1.0M] ESO PR Photo 35g/04 ESO PR Photo 35g/04 President Lagos with ESO Staff [Preview - JPEG: 500 x 400 pix - 192k] [Normal - JPEG: 1000 x 800 pix - 592k] [FullRes - JPEG: 1575 x 1200 pix - 1.1M] Captions: ESO PR Photo 35e/04 was obtained during President Lagos' meeting with ESO Staff at the Paranal Residencia. On ESO PR Photo 35f/04, President Lagos and Mrs. Luisa Duran de Lagos are seen at a quiet moment during the visit to the VLT Control Room, together with Prof. Maria Teresa Ruiz (far right), Head of the Astronomy Department at the Universidad de Chile, and the ESO Director General. ESO PR Photo 35g/04 shows President Lagos with some ESO staff members in the Paranal Residencia. VLT obtains a splendid photo of a unique galaxy, NGC 1097 ESO PR Photo 35d/04 ESO PR Photo 35d/04 Spiral Galaxy NGC 1097 (Melipal + VIMOS) [Preview - JPEG: 400 x 525 pix - 181k] [Normal - JPEG: 800 x 1049 pix - 757k] [FullRes - JPEG: 2296 x 3012 pix - 7.9M] Captions: ESO PR Photo 35d/04 is an almost-true colour composite based on three images made with the multi-mode VIMOS instrument on the 8.2-m Melipal (Unit Telescope 3) of ESO's Very Large Telescope. They were taken on the night of December 9-10, 2004, in the presence of the President of the Republic of Chile, Ricardo Lagos. Details are available in the Technical Note below. A unique and very beautiful image was obtained with the VIMOS instrument with President Lagos at the control desk. Located at a distance of about 45 million light-years in the southern constellation Fornax (the Furnace), NGC 1097 is a relatively bright, barred spiral galaxy of type SBb, seen face-on. At magnitude 9.5, and thus just 25 times fainter than the faintest object that can be seen with the unaided eye, it appears in small telescopes as a bright, circular disc. ESO PR Photo 35d/04, taken on the night of December 9 to 10, 2004 with the VIsible Multi-Object Spectrograph ("VIMOS), a four-channel multiobject spectrograph and imager attached to the 8.2-m VLT Melipal telescope, shows that the real structure is much more complicated. NGC 1097 is indeed a most interesting object in many respects. As this striking image reveals, NGC 1097 presents a centre that consists of a broken ring of bright knots surrounding the galaxy's nucleus. The sizes of these knots - presumably gigantic bubbles of hydrogen atoms having lost one electron (HII regions) through the intense radiation from luminous massive stars - range from roughly 750 to 2000 light-years. The presence of these knots suggests that an energetic burst of star formation has recently occurred. NGC 1097 is also known as an example of the so-called LINER (Low-Ionization Nuclear Emission Region Galaxies) class. Objects of this type are believed to be low-luminosity examples of Active Galactic Nuclei (AGN), whose emission is thought to arise from matter (gas and stars) falling into oblivion in a central black hole. There is indeed much evidence that a supermassive black hole is located at the very centre of NGC 1097, with a mass of several tens of million times the mass of the Sun. This is at least ten times more massive than the central black hole in our own Milky Way. However, NGC 1097 possesses a comparatively faint nucleus only, and the black hole in its centre must be on a very strict "diet": only a small amount of gas and stars is apparently being swallowed by the black hole at any given moment. A turbulent past As can be clearly seen in the upper part of PR Photo 35d/04, NGC 1097 also has a small galaxy companion; it is designated NGC 1097A and is located about 42,000 light-years away from the centre of NGC 1097. This peculiar elliptical galaxy is 25 times fainter than its big brother and has a "box-like" shape, not unlike NGC 6771, the smallest of the three galaxies that make up the famous Devil's Mask, cf. ESO PR Photo 12/04. There is evidence that NGC 1097 and NGC 1097A have been interacting in the recent past. Another piece of evidence for this galaxy's tumultuous past is the presence of four jets - not visible on this image - discovered in the 1970's on photographic plates. These jets are now believed to be the captured remains of a disrupted dwarf galaxy that passed through the inner part of the disc of NGC 1097. Moreover, another interesting feature of this active galaxy is the fact that no less than two supernovae were detected inside it within a time span of only four years. SN 1999eu was discovered by Japanese amateur Masakatsu Aoki (Toyama, Japan) on November 5, 1999. This 17th-magnitude supernova was a peculiar Type II supernova, the end result of the core collapse of a very massive star. And in the night of January 5 to 6, 2003, Reverend Robert Evans (Australia) discovered another Type II supernova of 15th magnitude. Also visible in this very nice image which was taken during very good sky conditions - the seeing was well below 1 arcsec - are a multitude of background galaxies of different colours and shapes. Given the fact that the total exposure time for this three-colour image was just 11 min, it is a remarkable feat, demonstrating once again the very high efficiency of the VLT.

Possible Overlaps Between Blobs, Grism Apertures, and Dithers

NASA Astrophysics Data System (ADS)

Ryan, R. E.; McCullough, P. R.

2017-06-01

We present a investigation into possible overlaps between the known IR blobs with the grism aperture reference positions and the IR dither patterns. Each aperture was designed to place the science target (e.g. a specific star) on a cosmetically clean area of the IR detector. Similarly, the dither patterns were designed to mitigate cosmetic defects by rarely (or ideally never) placing such targets on known defects. Because blobs accumulate with time, the originally defined apertures and dither patterns may no longer accomplish their goals, it is important to reverify these combinations. We find two potential overlaps between the blob, aperture, and dither combinations, but do not recommend any changes to the current suite of aperture references positions and/or dither patterns for two reasons. First, one of the overlaps occurs with a dither/aperture combination that is seldom used for high-value science operations, but rather more common for wide-field surveys/mosaics. Second, the other overlap is 8.7 pix from a blob that has a fiducial radius of 10 pix, which already represents a very conservative distance. We conclude that a similar analysis should be repeated as new blobs occur, to continue to ensure ideal operations for high-value science targets. The purpose of this report is to document the analysis in order to facilitate its repetition in the future.

Analysis and modification of blue sapphires from Rwanda by ion beam techniques

NASA Astrophysics Data System (ADS)

Bootkul, D.; Chaiwai, C.; Tippawan, U.; Wanthanachaisaeng, B.; Intarasiri, S.

2015-12-01

Blue sapphire is categorised in a corundum (Al2O3) group. The gems of this group are always amazed by their beauties and thus having high value. In this study, blue sapphires from Rwanda, recently came to Thai gemstone industry, are chosen for investigations. On one hand, we have applied Particle Induced X-ray Emission (PIXE), which is a highly sensitive and precise analytical technique that can be used to identify and quantify trace elements, for chemical analysis of the sapphires. Here we have found that the major element of blue sapphires from Rwanda is Al with trace elements such as Fe, Ti, Cr, Ga and Mg as are commonly found in normal blue sapphire. On the other hand, we have applied low and medium ion implantations for color improvement of the sapphire. It seems that a high amount of energy transferring during cascade collisions have altered the gems properties. We have clearly seen that the blue color of the sapphires have been intensified after nitrogen ion bombardment. In addition, the gems were also having more transparent and luster. The UV-Vis-NIR measurement detected the modification of their absorption properties, implying of the blue color increasing. Here the mechanism of these modifications is postulated and reported. In any point of view, the bombardment by using nitrogen ion beam is a promising technique for quality improvement of the blue sapphire from Rwanda.

Improvement of sensitivity in PIGE analysis of steels by neutron-gamma coincidences measurement

NASA Astrophysics Data System (ADS)

Ene, Antoaneta

2004-07-01

In this work the sensitivities of minor elements in a standard steel sample EURONORM-CRM No. 085-1 irradiated with beams of 5.5 MeV protons and 5 MeV deuterons have been determined both by regular proton- (p-PIGE) and deuteron-induced prompt gamma-ray emission (d-PIGE) methods and with the selection of the (p, n) and (d, n) reaction channels, measuring the neutron-gamma coincidences. A check on the elemental composition of the steel standard has also been carried out using combined INAA and PIXE and quantitative determinations have been done for some elements whose concentrations were not specified by the manufacturer, such as Al, As, Cr, Mo, Na, Ni, W. This complex study has resulted in a significant improvement of the sensitivities for some minor elements in steel by reducing the background and increasing the peak-to-background ratio in the coincident prompt gamma-rays spectra as a result of the elimination of the competing nuclear reactions originating from isotopes of the adjacent elements in the periodic table, present in the steel target. This extension of the PIGE method could be adapted by any analyst with the necessary equipment for the analysis of a wide variety of matrices that are refractory enough to withstand the heating effect of the bombarding beam, taking into account that this type of experiment requires longer irradiation times.

Nuclear microscopy in Alzheimer's disease

NASA Astrophysics Data System (ADS)

Makjanic, Jagoda; Watt, Frank

1999-04-01

The elemental composition of the two types of brain lesions which characterise Alzheimer's disease (AD) has been the subject of intense scrutiny over the last decade, ever since it was proposed that inorganic trace elements, particularly aluminium, might be implicated in the pathogenesis of the disease. The major evidence for this involvement was the detection of aluminium in the characteristic lesions of the AD brain; neuritic plaques and neurofibrillary tangles (NFTs). Using the powerful combination of Particle-Induced X-ray Emission (PIXE), Rutherford Backscattering Spectrometry (RBS) and Scanning Transmission Ion Microscopy (STIM), it is possible to image and analyse structures in brain sections without recourse to chemical staining. Previous results on elemental composition of senile plaques indicated the absence of aluminium at the 15 parts per million level. We have more recently focused on the analysis of neurofibrillary tangles (NFTs), destructive structural defects within neurons. Imaging and analysis of neurons in brain tissue presented a greater challenge due to the small dimensional size compared with the plaques. We describe the methodology and the results of imaging and analysing neurons in brain tissue sections using Nuclear Microscopy. Our results show that aluminium is not present in either neurons or surrounding tissue in unstained sections at the 20 ppm level, but can be observed in stained sections. We also report elemental concentrations showing significant elevations of phosphorus, sulphur, chlorine, iron and zinc.

Investigation of (Ti-Zr-Hf-V-Nb)N Multicomponent Nanostructured Coatings before and after Thermal Annealing by Nuclear Physics Methods of Analysis

NASA Astrophysics Data System (ADS)

Pogrebnjak, A. D.; Beresnev, V. M.; Bondar', A. V.; Kaverin, M. V.; Ponomarev, A. G.

2013-10-01

(Ti-Zr-Hf-V-Nb)N multicomponent nanostructured coatings with thickness of 1.0-1.4 μm synthesized by the method of cathode arc-vapor deposition at temperatures of 250-300°С are investigated by various mutually complementary methods of elemental structural analysis using slow positron beams (SPB), proton microbeam based particle-induced x-ray emission (μ-PIXE), energy-dispersive x-ray spectroscopy (EDS) and scanning electron microscopy (SEM) analyses based on electron micro- and nanobeams, x-ray diffraction (XRD) method of phase structural analysis, and the "a-sin2φ" method of measuring a stressed-strained state (x-ray tensometry). The elemental composition, microstructure, residual stress in nanograins, profiles of defect and atom distributions with depth and over the coating surface in 3D-representation are studied for these coatings, and their phase composition, severely strained state, and composition of coatings before and after annealing at Tann = 600°С for annealing time τ = 30 min are investigated. It is demonstrated that the oxidation resistance of the examined coatings can be significantly increased by high-temperature annealing that leads to the formation of elastic severely strained compression state of the coating. Redistribution of elements and defects, their segregation near the interface boundaries and around grains and subgrains in the process of thermostimulated diffusion, and termination of spinodal segregation without considerable change of the average nanograin size are revealed.

μPIXE for a μBrain: The vinegar fly's brain, antenna, sensilla hairs and eye ion concentrations

NASA Astrophysics Data System (ADS)

Reinert, Anja; Barapatre, Nirav; Sachse, Silke; Reinert, Tilo

2011-10-01

The vinegar fly Drosophila melanogaster is used as model organism to study a variety of different scientific purposes. Thus, our laboratory studies the olfactory system by neurobiological experiments. These techniques are often disruptive and need to compensate or exchange the body fluid, the lymph, with an artificial Ringer's solution in defined compartments of the fly. The solution mainly contains Na, Cl, K and Ca and is to keep physiological conditions. Therefore, the knowledge about the ion concentrations in the respective Drosophila lymph is required for a correct mixture of the ions. This paper presents the spatially resolved concentrations of P, S, Cl, K, Ca, Fe, Cu and Zn in lyophilised head cryosections of Drosophila by using quantitative μPIXE at the ion beam facility LIPSION in Leipzig. The PIXE maps enable a detailed analysis of particular regions of interest down to a spatial resolution of 0.5 μm. We quantified the ion concentrations especially in the brain, the antenna and its sensilla hairs acting as the olfactory organ of the fly, in the compound eye and in the mouthparts. The averaged element concentrations of these main compartments are (in descending order): P: 90 mM, K: 81 mM, S: 38 mM, Cl: 18 mM, Ca: 4.9 mM, Fe: 1.4 mM, Zn: 1.2 mM, Cu: 0.06 mM. Certain structures or cavities possess a remarkably high concentration of particular elements and might reflect the different functions of the compartments. An example presented in more detail is the composition of the compound eye. Conclusively, our findings on the ion concentrations might be useful for the mixture of the Drosophila Ringer's solution to ensure physiological conditions in experiments.

The use of nuclear muprobe techniques to study the chemistry of lacustrine sediments and particles

NASA Astrophysics Data System (ADS)

Grime, G. W.; Davison, W.

1993-05-01

The Oxford SPM has been used in two novel studies of lake chemistry: (a) The distribution of dissolved iron in sediment pore waters close to the sediment/water interface has been measured using the novel technique of diffusive equilibration in a thin film (DET). In this technique, which has a spatial resolution of < 1 mm, much less than that of competing techniques (1 cm), a thin layer of polyacrylamide gel is inserted into the sediment and after the rapid equilibration with the pore water, the gel is dried and fixed. The distribution of trace elements can then be measured using mubeam PIXE. Preliminary results have shown for the first time a subsurface maximum of Fe consistent with current theories of Fe dynamics. This paper presents some results obtained using the technique and discusses the limits on resolution and sensitivity, (b) Individual suspended lake particles (predominantly iron oxides and sulphides) have been analysed using point mubeam RBS and PIXE. Of particular interest in this study is the oxidation state of iron rich particles, so RBS with a 1 μm beam was used to determine the Fe: O stoichiometry of single particles. The particles were filtered from a depth of 14 m in Esthwaite Water in the English Lake District and handled in anoxic conditions until evacuation in the SPM sample chamber. Two distinct compositions of iron oxide were determined in clusters of about 5 μm diameter. Analysis by PIXE revealed that FeS was uniformly distributed in the particulate material and that it also contained elevated levels of Cu and Zn. This study was the first to demonstrate directly that discrete clusters of iron oxides are present in black particulate material which is commonly considered to comprise iron sulphides.

Multi-technique characterization of gold electroplating on silver substrates for cultural heritage applications

NASA Astrophysics Data System (ADS)

Ortega-Feliu, I.; Ager, F. J.; Roldán, C.; Ferretti, M.; Juanes, D.; Scrivano, S.; Respaldiza, M. A.; Ferrazza, L.; Traver, I.; Grilli, M. L.

2017-09-01

This work presents a detailed study of a series of silver plates gilded via electroplating techniques in which the characteristics of the coating gold layers are investigated as a function of the electroplating variables (voltage, time, anode surface and temperature). Some reference samples were coated by radio frequency sputtering in order to compare gold layer homogeneity and effective density. Surface analysis was performed by means of atomic and nuclear techniques (SEM-EDX, EDXRF, PIXE and RBS) to obtain information about thickness, homogeneity, effective density, profile concentration of the gold layers and Au-Ag diffusion profiles. The gold layer thickness obtained by PIXE and EDXRF is consistent with the thickness obtained by means of RBS depth profiling. Electroplated gold mass thickness increases with electroplating time, anode area and voltage. However, electrodeposited samples present rough interfaces and gold layer effective densities lower than the nominal density of Au (19.3 g/cm3), whereas sputtering produces uniform layers with nominal density. These analyses provide valuable information to historians and curators and can help the restoration process of gold-plated silver objects.

PIXE analysis of airborne particulate matter from Monterrey, Mexico. A first survey

NASA Astrophysics Data System (ADS)

Aldape, F.; Flores M, J.; Díaz, R. V.; Hernández-Méndez, B.; Montoya Z, J. M.; Blanco, E. E.; Fuentes, A. F.; Torres-Martínez, L. M.

1999-04-01

A first survey of elemental contents in airborne particulate matter from Monterrey, Nuevo León, Mexico, was performed using PIXE. This second largest industrial city is located 715 km north of Mexico City, and counts with a population of nearly three million inhabitants in its conurbation. Air pollution in the place comes from a great variety of industries ranging from iron smelters to furniture manufacturing, as well as from fuel combustion in vehicles and industries. This study presents results of elemental contents in airborne particulate matter in two particle size fractions: PM 2.5 and PM 15. The samples were collected during five weeks on working days, Monday-Friday, from 9 December 1996 to 14 January 1997. Two samples a day were collected, 12 h each, night-time and day-time. These first results show local pollution as typical from a large urban area in conjunction with an active industry. Thirteen elements were consistently detected in most of the samples and some episodes due to both industrial and human activities were identified. A general discussion about the results obtained is presented.

Analysis of metals with luster: Roman brass and silver

NASA Astrophysics Data System (ADS)

Fajfar, H.; Rupnik, Z.; Šmit, Ž.

2015-11-01

Non-destructive PIXE analysis using in-air proton beam was used for the studies of earliest brass coins issued during the 1st century BC by Greek cities in Asia Minor, Romans and Celts, and for the studies of plated low grade silver coins of the 3rd century AD. The analysis determined the levels of zinc and important trace elements, notably selenium, which confirms spread of selenium-marked copper from the east. For plating, combined tinning and silvering was identified by the mapping technique for the mid 3rd century AD, which evolved into mere plating by 270 AD.

Cadmium localization and quantification in the plant Arabidopsis thaliana using micro-PIXE

NASA Astrophysics Data System (ADS)

Ager, F. J.; Ynsa, M. D.; Domínguez-Solís, J. R.; Gotor, C.; Respaldiza, M. A.; Romero, L. C.

2002-04-01

Remediation of metal-contaminated soils and waters poses a challenging problem due to its implications in the environment and the human health. The use of metal-accumulating plants to remove toxic metals, including Cd, from soil and aqueous streams has been proposed as a possible solution to this problem. The process of using plants for environmental restoration is termed phytoremediation. Cd is a particularly favourable target metal for this technology because it is readily transported and accumulated in the shoots of several plant species. This paper investigates the sites of metal localization within Arabidopsis thaliana leaves, when plants are grown in a cadmium-rich environment, by making use of nuclear microscopy techniques. Micro-PIXE, RBS and SEM analyses were performed on the scanning proton microprobe at the CNA in Seville (Spain), showing that cadmium is sequestered within the trichomes on the leaf surface. Additionally, regular PIXE analyses were performed on samples prepared by an acid digestion method in order to assess the metal accumulation of such plants.

A smart-phone application and a companion website for the improvement of the communication skills of children with autism: clinical rationale, technical development and preliminary results.

PubMed

De Leo, Gianluca; Gonzales, Carol H; Battagiri, Padmaja; Leroy, Gondy

2011-08-01

Autism is a complex neurobiological disorder that is part of a group of disorders known as autism spectrum disorders (ASD). Today, one in 150 individuals is diagnosed with autism. Lack of social interaction and problems with communication are the main characteristics displayed by children with ASD. The Picture Exchange Communication System (PECS) is a communication system where children exchange visual symbols as a form of communication. The visual symbols are laminated pictures stored in a binder. We have designed, developed and are currently testing a software application, called PixTalk which works on any Windows Mobile Smart-phone. Teachers and caregivers can access a web site and select from an online library the images to be downloaded on to the Smart-phone. Children can browse and select images to express their intentions, desires, and emotions using PixTalk. Case study results indicate that PixTalk can be used as part of ongoing therapy.

High resolution rare-earth elements analyses of natural apatite and its application in geo-sciences: Combined micro-PIXE, quantitative CL spectroscopy and electron spin resonance analyses

NASA Astrophysics Data System (ADS)

Habermann, D.; Götte, T.; Meijer, J.; Stephan, A.; Richter, D. K.; Niklas, J. R.

2000-03-01

The rare-earth element (REE) distribution in natural apatite is analysed by micro-PIXE, cathodoluminescence (CL) microscopy and spectroscopy and electron spin resonance (ESR) spectroscopy. The micro-PIXE analyses of an apatite crystal from Cerro de Mercado (Mexico) and the summary of 20 analyses of six francolite (conodonts of Triassic age) samples indicate that most of the REEs are enriched in apatite and francolite comparative to average shale standard (NASC). The analyses of fossil francolite revealing the REE-distribution not to be in balance with the REE-distribution of seawater and fish bone debris. Strong inhomogenous lateral REE-distribution in fossil conodont material is shown by CL-mapping and most probably not being a vital effect. Therefore, the resulting REE-signal from fossil francolite is the sum of vital and post-mortem incorporation. The necessary charge compensation for the substitution of divalent Ca by trivalent REE being done by different kind of electron defects and defect ions.

Evaluation of the radiation hazard for ion-beam analysis with MeV external proton beams (X-IBA)

NASA Astrophysics Data System (ADS)

Hofsäss, Hans

2018-07-01

MeV ion beams which are extracted into air or He atmosphere are used in many labs for proton-induced X-ray emission (PIXE), proton induced gamma ray emission (PIGE) or Rutherford backscattering (RBS) to analyze samples which are difficult or impossible to handle in vacuum. When MeV proton beams are extracted into air through thin Kapton foils or nowadays thin silicon nitride membranes, the protons will interact with air, as well as elements present in the analyzed samples. Typically the range of MeV protons in air is several cm, in Helium atmosphere several 10 cm and in human skin around 100 μm. Besides the severe radiation hazard in case of a direct exposure of skin with protons, there are a manifold of nuclear reactions or inelastic proton scattering processes which may cause activation of air and target materials but also prompt radiation. The radiation hazard associated with the direct and scattered beam, nuclear reaction products and radionuclide production in air have been discussed in a publication by Doyle et al. in 1991 which was used as a reference in several later publications. I have reevaluated the radiation hazards for external proton beams with up to 4.5 MeV using proton reaction cross sections taken from the JANIS book of proton induced cross sections. The radionuclide production in air is about 3 orders of magnitude lower compared to values given in the 1991 publication. Radionuclide production as well as generation of prompt alpha, gamma and neutron radiation in target materials for elements up to molybdenum is also evaluated.

Energetic electron processes fluorescence effects for structured nanoparticles X-ray analysis and nuclear medicine applications

NASA Astrophysics Data System (ADS)

Taborda, A.; Desbrée, A.; Carvalho, A.; Chaves, P. C.; Reis, M. A.

2016-08-01

Superparamagnetic iron oxide (SPIO) nanoparticles are widely used as contrast agents for nuclear magnetic resonance imaging (MRI), and can be modified for improved imaging or to become tissue-specific or even protein-specific. The knowledge of their detailed elemental composition characterisation and potential use in nuclear medicine applications, is, therefore, an important issue. X-ray fluorescence techniques such as particle induced X-ray emission (PIXE) or X-ray fluorescence spectrometry (XRF), can be used for elemental characterisation even in problematic situations where very little sample volume is available. Still, the fluorescence coefficient of Fe is such that, during the decay of the inner-shell ionised atomic structure, keV Auger electrons are produced in excess to X-rays. Since cross-sections for ionisation induced by keV electrons, for low atomic number atoms, are of the order of 103 barn, care should be taken to account for possible fluorescence effects caused by Auger electrons, which may lead to the wrong quantification of elements having atomic number lower than the atomic number of Fe. Furthermore, the same electron processes will occur in iron oxide nanoparticles containing 57Co, which may be used for nuclear medicine therapy purposes. In the present work, simple approximation algorithms are proposed for the quantitative description of radiative and non-radiative processes associated with Auger electrons cascades. The effects on analytical processes and nuclear medicine applications are quantified for the case of iron oxide nanoparticles, by calculating both electron fluorescence emissions and energy deposition on cell tissues where the nanoparticles may be embedded.

Analysis of Greek small coinage from the classic period

NASA Astrophysics Data System (ADS)

Šmit, Ž.; Šemrov, A.

2018-02-01

A series of 25 Greek coins from the 6th to 4th centuries BC was studied by PIXE for their trace element composition, with an aim to discover the origin of their silver ore. The procedure revealed a counterfeited coin, and then concentrated on distinguishing the coins minted from the ore of Laurion on the Attica peninsula and the coins minted from other sources. Linear discriminant analysis based on the impurities and alloying elements of copper, gold, lead and bismuth revealed that discrimination is indeed possible according to a single canonical variable.

A scanning proton microprobe study of stinging emergences from the leaf of the common stinging nettle urtica dioica l.

NASA Astrophysics Data System (ADS)

Hughes, N. P.; Perry, C. C.; Williams, R. J. P.; Watt, F.; Grime, G. W.

1988-03-01

Proton-induced X-ray emission (PIXE) combined with the Oxford scanning proton microprobe (SPM) was used to investigate the abundance and spatial distribution of inorganic elements in mineralising stinging emergences from the leaf of the Common Stinging Nettle, Urtica dioica L. Elemental maps and point analytical data were collected for emergences at two stages of maturity. In all emergences calcium and silicon were spatially organised and present at high concentration. The inorganic elements K, P, S and Mn were also spatially organised during mineralisation, but at maturity these elements were present only at background levels and then showed no specific localisation. The observed changes in the inorganic content of the emergences are obviously related to the mineralisation processes. The possible biochemical significance of the distribution of the elements is discussed.

Aerosol composition and source apportionment in Santiago de Chile

NASA Astrophysics Data System (ADS)

Artaxo, Paulo; Oyola, Pedro; Martinez, Roberto

1999-04-01

Santiago de Chile, São Paulo and Mexico City are Latin American urban areas that suffer from heavy air pollution. In order to study air pollution in Santiago area, an aerosol source apportionment study was designed to measure ambient aerosol composition and size distribution for two downtown sampling sites in Santiago. The aerosol monitoring stations were operated in Gotuzo and Las Condes during July and August 1996. The study employed stacked filter units (SFU) for aerosol sampling, collecting fine mode aerosol (dp<2 μm) and coarse mode aerosol (2

VIMOS - a Cosmology Machine for the VLT

NASA Astrophysics Data System (ADS)

2002-03-01

Successful Test Observations With Powerful New Instrument at Paranal [1] Summary One of the most fundamental tasks of modern astrophysics is the study of the evolution of the Universe . This is a daunting undertaking that requires extensive observations of large samples of objects in order to produce reasonably detailed maps of the distribution of galaxies in the Universe and to perform statistical analysis. Much effort is now being put into mapping the relatively nearby space and thereby to learn how the Universe looks today . But to study its evolution, we must compare this with how it looked when it still was young . This is possible, because astronomers can "look back in time" by studying remote objects - the larger their distance, the longer the light we now observe has been underway to us, and the longer is thus the corresponding "look-back time". This may sound easy, but it is not. Very distant objects are very dim and can only be observed with large telescopes. Looking at one object at a time would make such a study extremely time-consuming and, in practical terms, impossible. To do it anyhow, we need the largest possible telescope with a highly specialised, exceedingly sensitive instrument that is able to observe a very large number of (faint) objects in the remote universe simultaneously . The VLT VIsible Multi-Object Spectrograph (VIMOS) is such an instrument. It can obtain many hundreds of spectra of individual galaxies in the shortest possible time; in fact, in one special observing mode, up to 6400 spectra of the galaxies in a remote cluster during a single exposure, augmenting the data gathering power of the telescope by the same proportion. This marvellous science machine has just been installed at the 8.2-m MELIPAL telescope, the third unit of the Very Large Telescope (VLT) at the ESO Paranal Observatory. A main task will be to carry out 3-dimensional mapping of the distant Universe from which we can learn its large-scale structure . "First light" was achieved on February 26, 2002, and a first series of test observations has successfully demonstrated the huge potential of this amazing facility. Much work on VIMOS is still ahead during the coming months in order to put into full operation and fine-tune the most efficient "galaxy cruncher" in the world. VIMOS is the outcome of a fruitful collaboration between ESO and several research institutes in France and Italy, under the responsibility of the Laboratoire d'Astrophysique de Marseille (CNRS, France). The other partners in the "VIRMOS Consortium" are the Laboratoire d'Astrophysique de Toulouse, Observatoire Midi-Pyrénées, and Observatoire de Haute-Provence in France, and Istituto di Radioastronomia (Bologna), Istituto di Fisica Cosmica e Tecnologie Relative (Milano), Osservatorio Astronomico di Bologna, Osservatorio Astronomico di Brera (Milano) and Osservatorio Astronomico di Capodimonte (Naples) in Italy. PR Photo 09a/02 : VIMOS image of the Antennae Galaxies (centre). PR Photo 09b/02 : First VIMOS Multi-Object Spectrum (full field) PR Photo 09c/02 : The VIMOS instrument on VLT MELIPAL PR Photo 09d/02 : The VIMOS team at "First Light". PR Photo 09e/02 : "First Light" image of NGC 5364 PR Photo 09f/02 : Image of the Crab Nebula PR Photo 09g/02 : Image of spiral galaxy NGC 2613 PR Photo 09h/02 : Image of spiral galaxy Messier 100 PR Photo 09i/02 : Image of cluster of galaxies ACO 3341 PR Photo 09j/02 : Image of cluster of galaxies MS 1008.1-1224 PR Photo 09k/02 : Mask design for MOS exposure PR Photo 09l/02 : First VIMOS Multi-Object Spectrum (detail) PR Photo 09m/02 : Integrated Field Spectroscopy of central area of the "Antennae Galaxies" PR Photo 09n/02 : Integrated Field Spectroscopy of central area of the "Antennae Galaxies" (detail) Science with VIMOS ESO PR Photo 09a/02 ESO PR Photo 09a/02 [Preview - JPEG: 400 x 469 pix - 152k] [Normal - JPEG: 800 x 938 pix - 408k] ESO PR Photo 09b/02 ESO PR Photo 09b/02 [Preview - JPEG: 400 x 511 pix - 304k] [Normal - JPEG: 800 x 1022 pix - 728k] Caption : PR Photo 09a/02 : One of the first images from the new VIMOS facility, obtained right after the moment of "first light" on Ferbruary 26, 2002. It shows the famous "Antennae Galaxies" (NGC 4038/39), the result of a recent collision between two galaxies. As an immediate outcome of this dramatic event, stars are born within massive complexes that appear blue in this composite photo, based on exposures through green, orange and red optical filtres. PR Photo 09b/02 : Some of the first spectra of distant galaxies obtained with VIMOS in Multi-Object-Spectroscopy (MOS) mode. More than 220 galaxies were observed simultaneously, an unprecedented efficiency for such a "deep" exposure, reaching so far out in space. These spectra allow to obtain the redshift, a measure of distance, as well as to assess the physical status of the gas and stars in each of these galaxies. A part of this photo is enlarged as PR Photo 09l/02. Technical information about these photos is available below. Other "First Light" images from VIMOS are shown in the photo gallery below. The next in the long series of front-line instruments to be installed on the ESO Very Large Telescope (VLT), VIMOS (and its complementary, infrared-sensitive counterpart NIRMOS, now in the design stage) will allow mapping of the distribution of galaxies, clusters, and quasars during a time interval spanning more than 90% of the age of the universe. It will let us look back in time to a moment only ~1.5 billion years after the Big Bang (corresponding to a redshift of about 5). Like archaeologists, astronomers can then dig deep into those early ages when the first building blocks of galaxies were still in the process of formation. They will be able to determine when most of the star formation occurred in the universe and how it evolved with time. They will analyse how the galaxies cluster in space, and how this distribution varies with time. Such observations will put important constraints on evolution models, in particular on the average density of matter in the Universe. Mapping the distant universe requires to determine the distances of the enormous numbers of remote galaxies seen in deep pictures of the sky, adding depth - the third, indispensible dimension - to the photo. VIMOS offers this capability, and very efficiently. Multi-object spectroscopy is a technique by which many objects are observed simultaneously. VIMOS can observe the spectra of about 1000 galaxies in one exposure, from which redshifts, hence distances, can be measured [2]. The possibility to observe two galaxies at once would be equivalent to having a telescope twice the size of a VLT Unit Telescope. VIMOS thus effectively "increases" the size of the VLT hundreds of times. From these spectra, the stellar and gaseous content and internal velocities of galaxies can be infered, forming the base for detailed physical studies. At present the distances of only a few thousand galaxies and quasars have been measured in the distant universe. VIMOS aims at observing 100 times more, over one hundred thousand of those remote objects. This will form a solid base for unprecedented and detailed statistical studies of the population of galaxies and quasars in the very early universe. The international VIRMOS Consortium VIMOS is one of two major astronomical instruments to be delivered by the VIRMOS Consortium of French and Italian institutes under a contract signed in the summer of 1997 between the European Southern Observatory (ESO) and the French Centre National de la Recherche Scientifique (CNRS). The participating institutes are: in France: * Laboratoire d'Astrophysique de Marseille (LAM), Observatoire Marseille-Provence (project responsible) * Laboratoire d'Astrophysique de Toulouse, Observatoire Midi-Pyrénées * Observatoire de Haute-Provence (OHP) in Italy: * Istituto di Radioastronomia (IRA-CNR) (Bologna) * Istituto di Fisica Cosmica e Tecnologie Relative (IFCTR) (Milano) * Osservatorio Astronomico di Capodimonte (OAC) (Naples) * Osservatorio Astronomico di Bologna (OABo) * Osservatorio Astronomico di Brera (OABr) (Milano) VIMOS at the VLT: a unique and powerful combination ESO PR Photo 09c/02 ESO PR Photo 09c/02 [Preview - JPEG: 501 x 400 pix - 312k] [Normal - JPEG: 1002 x 800 pix - 840k] Caption : PR Photo 09c/02 shows the new VIMOS instrument on one of the Nasmyth platforms of the 8.2-m VLT MELIPAL telescope at Paranal. VIMOS is installed on the Nasmyth "Focus B" platform of the 8.2-m VLT MELIPAL telescope, cf. PR Photo 09c/02 . It may be compared to four multi-mode instruments of the FORS-type (cf. ESO PR 14/98 ), joined in one stiff structure. The construction of VIMOS has involved the production of large and complex optical elements and their integration in more than 30 remotely controlled, finely moving functions in the instrument. In the configuration employed for the "first light", VIMOS made use of two of its four channels. The two others will be put into operation in the next commissioning period during the coming months. However, VIMOS is already now the most efficient multi-object spectrograph in the world , with an equivalent (accumulated) slit length of up to 70 arcmin on the sky. VIMOS has a field-of-view as large as half of the full moon (14 x 16 arcmin 2 for the four quadrants), the largest sky field to be imaged so far by the VLT. It has excellent sensitivity in the blue region of the spectrum (about 60% more efficient than any other similar instruments in the ultraviolet band), and it is also very sensitive in all other visible spectral regions, all the way to the red limit. But the absolutely unique feature of VIMOS is its capability to take large numbers of spectra simultaneously , leading to exceedingly efficient use of the observing time. Up to about 1000 objects can be observed in a single exposure in multi-slit mode. And no less than 6400 spectra can be recorded with the Integral Field Unit , in which a closely packed fibre optics bundle can simultaneously observe a continuous sky area measuring no less than 56 x 56 arcsec 2. A dedicated machine, the Mask Manufacturing Unit (MMU) , cuts the slits for the entrance apertures of the spectrograph. The laser is capable of cutting 200 slits in less than 15 minutes. This facility was put into operation at Paranal by the VIRMOS Consortium already in August 2000 and has since been extensively used for observations with the FORS2 instrument; more details are available in ESO PR 19/99. Fast start-up of VIMOS at Paranal ESO PR Photo 09d/02 ESO PR Photo 09d/02 [Preview - JPEG: 473 x 400 pix - 280k] [Normal - JPEG: 946 x 1209 pix - 728k] ESO PR Photo 09e/02 ESO PR Photo 09e/02 [Preview - JPEG: 400 x 438 pix - 176k] [Normal - JPEG: 800 x 876 pix - 664k] Caption : PR Photo 09d/02 : The VIRMOS team in the MELIPAL control room, moments after "First Light" on February 26, 2002. From left to right: Oreste Caputi, Marco Scodeggio, Giovanni Sciarretta , Olivier Le Fevre, Sylvie Brau-Nogue, Christian Lucuix, Bianca Garilli, Markus Kissler-Patig (in front), Xavier Reyes, Michel Saisse, Luc Arnold and Guido Mancini . PR Photo 09e/02 : The spiral galaxy NGC 5364 was the first object to be observed by VIMOS. This false-colour near-infrared, raw "First Light" photo shows the extensive spiral arms. Technical information about this photo is available below. VIMOS was shipped from Observatoire de Haute-Provence (France) at the end of 2001, and reassembled at Paranal during a first period in January 2002. From mid-February, the instrument was made ready for installation on the VLT MELIPAL telescope; this happened on February 24, 2002. VIMOS saw "First Light" just two days later, on February 26, 2000, cf. PR Photo 09e/02 . During the same night, a number of excellent images were obtained of various objects, demonstrating the fine capabilities of the instrument in the "direct imaging"-mode. The first spectra were successfully taken during the night of March 2 - 3, 2002 . The slit masks that were used on this occasion were prepared with dedicated software that also optimizes the object selection, cf. PR Photo 09k/02 , and were then cut with the laser machine. From the first try on, the masks have been well aligned on the sky objects. The first observations with large numbers of spectra were obtained shortly thereafter. First accomplishments Images of nearby galaxies, clusters of galaxies, and distant galaxy fields were among the first to be obtained, using the VIMOS imaging mode and demonstrating the excellent efficiency of the instrument, various examples are shown below. The first observations of multi-spectra were performed in a selected sky field in which many faint galaxies are present; it is known as the "VIRMOS-VLT Deep Survey Field at 1000+02". Thanks to the excellent sensitivity of VIMOS, the spectra of galaxies as faint as (red) magnitude R = 23 (i.e. over 6 million times fainter than what can be perceived with the unaided eye) are visible on exposures lasting only 15 minutes. Some of the first observations with the Integral Field Unit were made of the core of the famous Antennae Galaxies (NGC 4038/39) . They will form the basis for a detailed map of the strong emission produced by the current, dramatic collision of the two galaxies. First Images and Spectra from VIMOS - a Gallery The following photos are from a collection of the first images and spectra obtained with VIMOS . See also PR Photos 09a/02 , 09b/02 and 09e/02 , reproduced above. Technical information about all of them is available below. ESO PR Photo 09f/02 ESO PR Photo 09f/02 [Preview - JPEG: 400 x 469 pix - 224k] [Normal - JPEG: 800 x 937 pix - 544k] [HiRes - JPEG: 2001 x 2343 pix - 3.6M] Caption : PR Photo 09f/02 : The Crab Nebula (Messier 1) , as observed by VIMOS. This well-known object is the remnant of a stellar explosion in the year 1054. ESO PR Photo 09g/02 ESO PR Photo 09g/02 [Preview - JPEG: 478 x 400 pix - 184k] [Normal - JPEG: 956 x 1209 pix - 416k] [HiRes - JPEG: 1801 x 1507 pix - 1.4M] Caption : PR Photo 09g/02 : VIMOS photo of NGC 2613 , a spiral galaxy that ressembles our own Milky Way. ESO PR Photo 09h/02 ESO PR Photo 09h/02 [Preview - JPEG: 400 x 469 pix - 152k] [Normal - JPEG: 800 x 938 pix - 440k] [HiRes - JPEG: 1800 x 2100 pix - 2.0M] Caption : PR Photo 09h/02 : Messier 100 is one of the largest and brightest spiral galaxies in the sky. ESO PR Photo 09i/02 ESO PR Photo 09i/02 [Preview - JPEG: 400 x 405 pix - 144k] [Normal - JPEG: 800 x 810 pix - 312k] Caption : PR Photo 09i/02 : The cluster of galaxies ACO 3341 is located at a distance of about 300 million light-years (redshift z = 0.037), i.e., comparatively nearby in cosmological terms. It contains a large number of galaxies of different size and brightness that are bound together by gravity. ESO PR Photo 09j/02 ESO PR Photo 09j/02 [Preview - JPEG: 447 x 400 pix - 200k] [Normal - JPEG: 893 x 800 pix - 472k] [HiRes - JPEG: 1562 x 1399 pix - 1.1M] Caption : PR Photo 09j/02 : The distant cluster of galaxies MS 1008.1-1224 is some 3 billion light-years distant (redshift z = 0.301). The galaxies in this cluster - that we observe as they were 3 billion years ago - are different from galaxies in our neighborhood; their stellar populations, on the average, are younger. ESO PR Photo 09k/02 ESO PR Photo 09k/02 [Preview - JPEG: 400 x 455 pix - 280k] [Normal - JPEG: 800 x 909 pix - 696k] Caption : PR Photo 09k/02 : Design of a Mask for Multi-Object Spectroscopy (MOS) observations with VIMOS. The mask serves to block, as far as possible, unwanted background light from the "night sky" (radiation from atoms and molecules in the Earth's upper atmosphere). During the set-up process for multi-object observations, the VIMOS software optimizes the position of the individual slits in the mask (one for each object for which a spectrum will be obtained) before these are cut. The photo shows an example of this fitting process, with the slit contours superposed on a short pre-exposure of the sky field to be observed. ESO PR Photo 09l/02 ESO PR Photo 09l/02 [Preview - JPEG: 470 x 400 pix - 200k] [Normal - JPEG: 939 x 800 pix - 464k] Caption : PR Photo 09l/02 : First Multi-Object Spectroscopy (MOS) observations with VIMOS; enlargement of a small part of the field shown in PR Photo 09b/02. The light from each galaxy passes through the dedicated slit in the mask (see PR Photo 09k/02 ) and produces a spectrum on the detector. Each vertical rectangle contains the spectrum of one galaxy that is located several billion light-years away. The horizontal lines are the strong emission from the "night sky" (radiation from atoms and molecules in the Earth's upper atmosphere), while the vertical traces are the spectral signatures of the galaxies. The full field contains the spectra of over 220 galaxies that were observed simultaneously, illustrating the great efficiency of this technique. Later, about 1000 spectra will be obtained in one exposure. ESO PR Photo 09m/02 ESO PR Photo 09m/02 [Preview - JPEG: 470 x 400 pix - 264k] [Normal - JPEG: 939 x 800 pix - 720k] Caption : PR Photo 09m/02 : was obtained with the Integral Field Spectroscopy mode of VIMOS. In one single exposure, more than 3000 spectra were taken of the central area of the Antennae Galaxies ( PR Photo 09a/02 ). ESO PR Photo 09n/02 ESO PR Photo 09n/02 [Preview - JPEG: 532 x 400 pix - 320k] [Normal - JPEG: 1063 x 800 pix - 864k] Caption : PR Photo 09n/02 : An enlargement of a small area in PR Photo 09m/02. This observation allows mapping of the distribution of elements like hydrogen (H) and sulphur (S II), for which the signatures are clearly identified in these spectra. The wavelength increases towards the top (arrow). Notes [1]: This is a joint Press Release of ESO , Centre National de la Recherche Scientifique (CNRS) in France, and Consiglio Nazionale delle Ricerche (CNR) and Istituto Nazionale di Astrofisica (INAF) in Italy. [2]: In astronomy, the redshift denotes the fraction by which the lines in the spectrum of an object are shifted towards longer wavelengths. The observed redshift of a distant galaxy gives a direct estimate of the apparent recession velocity as caused by the universal expansion. Since the expansion rate increases with distance, the velocity is itself a function (the Hubble relation) of the distance to the object. Technical information about the photos PR Photo 09a/01 : Composite VRI image of NGC 4038/39, obtained on 26 February 2002, in a bright sky (full moon). Individual exposures of 60 sec each; image quality 0.6 arcsec FWHM; the field measures 3.5 x 3.5 arcmin 2. North is up and East is left. PR Photo 09b/02 : MOS-spectra obtained with two quadrants totalling 221 slits + 6 reference objects (stars placed in square holes to ensure a correct alignment). Exposure time 15 min; LR(red) grism. This is the raw (unprocessed) image of the spectra. PR Photo 09e/02 : A 60 sec i exposure of NGC 5364 on February 26, 2002; image quality 0.6 arcsec FWHM; full moon; 3.5 x 3.5 arcmin 2 ; North is up and East is left. PR Photo 09f/02 : Composite VRI image of Messier 1, obtained on March 4, 2002. The individual exposures lasted 180 sec; image quality 0.7 arcsec FWHM; field 7 x 7 arcmin 2 ; North is up and East is left. PR Photo 09g/02 : Composite VRI image of NGC 2613, obtained on February 28, 2002. The individual exposures lasted 180 sec; image quality 0.7 arcsec FWHM; field 7 x 7 arcmin 2 ; North is up and East is left. PR Photo 09h/02 : Composite VRI image of Messier 100, obtained on March 3, 2002. The individual exposures lasted 180 sec, image quality 0.7 arcsec FWHM; field 7 x 7 arcmin 2 ; North is up and East is left. PR Photo 09i/02 : R-band image of galaxy cluster ACO 3341, obtained on March 4, 2002. Exposure 300 sec, image quality 0.5 arcsec FWHM;. field 7 x 7 arcmin 2 ; North is up and East is left. PR Photo 09j/02 : Composite VRI image of the distant cluster of galaxies MS 1008.1-1224. The individual exposures lasted 300 sec; image quality 0.8 arcsec FWHM; field 5 x 3 arcmin 2 ; North is to the right and East is up. PR Photo 09k/02 : Mask design made with the VMMPS tool, overlaying a pre-image. The selected objects are seen at the centre of the yellow squares, where a 1 arcsec slit is cut along the spatial X-axis. The rectangles in white represent the dispersion in wavelength of the spectra along the Y-axis. Masks are cut with the Mask Manufacturing Unit (MMU) built by the Virmos Consortium. PR Photo 09l/02 : Enlargement of a small area of PR Photo 09b/02. PR Photo 09m/02 : Spectra of the central area of NGC 4038/39, obtained with the Integral Field Unit on February 26, 2002. The exposure lasted 5 min and was made with the low resolution red grating. PR Photo 09m/02 : Zoom-in on small area of PR Photo 09m/02. The strong emission lines of hydrogen (H-alpha) and ionized sulphur (S II) are seen.

Defects, stoichiometry, and electronic transport in SrTiO{sub 3-δ} epilayers: A high pressure oxygen sputter deposition study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ambwani, P.; Xu, P.; Jeong, J. S.

SrTiO{sub 3} is not only of enduring interest due to its unique dielectric, structural, and lattice dynamical properties, but is also the archetypal perovskite oxide semiconductor and a foundational material in oxide heterostructures and electronics. This has naturally focused attention on growth, stoichiometry, and defects in SrTiO{sub 3}, one exciting recent development being such precisely stoichiometric defect-managed thin films that electron mobilities have finally exceeded bulk crystals. This has been achieved only by molecular beam epitaxy, however (and to a somewhat lesser extent pulsed laser deposition (PLD)), and numerous open questions remain. Here, we present a study of the stoichiometry,more » defects, and structure in SrTiO{sub 3} synthesized by a different method, high pressure oxygen sputtering, relating the results to electronic transport. We find that this form of sputter deposition is also capable of homoepitaxy of precisely stoichiometric SrTiO{sub 3}, but only provided that substrate and target preparation, temperature, pressure, and deposition rate are carefully controlled. Even under these conditions, oxygen-vacancy-doped heteroepitaxial SrTiO{sub 3} films are found to have carrier density, mobility, and conductivity significantly lower than bulk. While surface depletion plays a role, it is argued from particle-induced X-ray emission (PIXE) measurements of trace impurities in commercial sputtering targets that this is also due to deep acceptors such as Fe at 100's of parts-per-million levels. Comparisons of PIXE from SrTiO{sub 3} crystals and polycrystalline targets are shown to be of general interest, with clear implications for sputter and PLD deposition of this important material.« less

Baccharis trimera (Less.) DC as genotoxicity indicator of exposure to coal and emissions from a thermal power plant.

PubMed

Menezes, Ana Paula Simões; Da Silva, Juliana; Roloff, Joice; Reyes, Juliana; Debastiani, Rafaela; Dias, Johnny F; Rohr, Paula; de Barros Falcão Ferraz, Alexandre

2013-10-01

During coal combustion, hazardous elements are discharged that impair environmental quality. Plant cover is the first available surface for the atmospheric pollutants in terrestrial ecosystems. The aim of this study was to evaluate genotoxicity in the aqueous extract of the native plant, Baccharis trimera, exposed to coal and emissions from a thermal power plant (coal-fired power plant in Candiota, Brazil), correlating seasonality, wind tunnel predominance, and presence of inorganic elements. The presence of inorganic elements in the aerial parts of B. trimera was analyzed by particle-induced X-ray emission (PIXE) spectrometry, and genotoxicity was evaluated by ex vivo comet assay. The genotoxic effects of aqueous extracts of B. trimera from four sites located in the area around power plant were analyzed by comet assay in peripheral human lymphocytes. Winter samples showed greater levels of metals than summer samples. Genotoxicity was detected in B. trimera extracts collected from the region exposed to extraction and burning coal. Extracts from the site impacted by the dominant wind induced more damage to DNA than those from other sites. Based on our data, we can suggest that in winter the inorganic elements from extraction and burning of coal and carried through the wind tunnel were responsible for the genotoxicity observed in aqueous extract of B. trimera.

The PixFEL project: Progress towards a fine pitch X-ray imaging camera for next generation FEL facilities

NASA Astrophysics Data System (ADS)

Rizzo, G.; Batignani, G.; Benkechkache, M. A.; Bettarini, S.; Casarosa, G.; Comotti, D.; Dalla Betta, G.-F.; Fabris, L.; Forti, F.; Grassi, M.; Lodola, L.; Malcovati, P.; Manghisoni, M.; Mendicino, R.; Morsani, F.; Paladino, A.; Pancheri, L.; Paoloni, E.; Ratti, L.; Re, V.; Traversi, G.; Vacchi, C.; Verzellesi, G.; Xu, H.

2016-07-01

The INFN PixFEL project is developing the fundamental building blocks for a large area X-ray imaging camera to be deployed at next generation free electron laser (FEL) facilities with unprecedented intensity. Improvement in performance beyond the state of art in imaging instrumentation will be explored adopting advanced technologies like active edge sensors, a 65 nm node CMOS process and vertical integration. These are the key ingredients of the PixFEL project to realize a seamless large area focal plane instrument composed by a matrix of multilayer four-side buttable tiles. In order to minimize the dead area and reduce ambiguities in image reconstruction, a fine pitch active edge thick sensor is being optimized to cope with very high intensity photon flux, up to 104 photons per pixel, in the range from 1 to 10 keV. A low noise analog front-end channel with this wide dynamic range and a novel dynamic compression feature, together with a low power 10 bit analog to digital conversion up to 5 MHz, has been realized in a 110 μm pitch with a 65 nm CMOS process. Vertical interconnection of two CMOS tiers will be also explored in the future to build a four-side buttable readout chip with high density memories. In the long run the objective of the PixFEL project is to build a flexible X-ray imaging camera for operation both in burst mode, like at the European X-FEL, or in continuous mode with the high frame rates anticipated for future FEL facilities.

PIEX and neurological diseases

NASA Astrophysics Data System (ADS)

Van Rinsvelt, H. A.; Hurd, R. W.; Kondoro, J. W. A.; Andres, J. M.; Mickle, J. P.; Wilder, B. J.; Maenhaut, W.; De Reu, L.

1984-04-01

Preliminary studies in our laboratories indicated alterations of specific trace metals in humans and animals treated with valproic acid (VPA), an anticonvulsant, and in animals treated with 4-pentenoic acid (4-PA), a fatty acid which produces a Reyes Syndrome-like condition. In this study, we report the results of PIXE analysis of plasma, liver, and brain of rats treated with VPA and 4-PA. Tissue specific changes in selenium, zinc and calcium may underly the pathophysiological changes produced by these chemicals.

The international fine aerosol networks

NASA Astrophysics Data System (ADS)

Cahill, Thomas A.

1993-04-01

The adoption by the United States of a PIXE-based protocol for its fine aerosol network, after open competitions involving numerous laboratories and methods, has encouraged cooperation with other countries possessing similar capabilities and similar needs. These informal cooperative programs, involving about a dozen countries at the end of 1991, almost all use PIXE as a major component of the analytical protocols. The University of California, Davis, Air Quality Group assisted such programs through indefinite loans of a quality assurance sampler, the IMPROVE Channel A, and analyses at no cost of a small fraction of the samples taken in a side-by-side configuration. In December 1991, the World Meteorological Organization chose a protocol essentially identical to IMPROVE for the Global Atmospheric Watch (GAW) network and began deploying units, the IMPROVE Channel A, to sites around the world. Preferred analyses include fine (less than about 2.5 μm) mass, ions by ion chromatography and elements by PIXE + PESA (or, lacking that, XRF). This paper will describe progress in both programs, giving examples of the utility of the data and projecting the future expansion of the network to about 20 GAW sites by 1994.

NASCAP simulation of PIX 2 experiments

NASA Technical Reports Server (NTRS)

Roche, J. C.; Mandell, M. J.

1985-01-01

The latest version of the NASCAP/LEO digital computer code used to simulate the PIX 2 experiment is discussed. NASCAP is a finite-element code and previous versions were restricted to a single fixed mesh size. As a consequence the resolution was dictated by the largest physical dimension to be modeled. The latest version of NASCAP/LEO can subdivide selected regions. This permitted the modeling of the overall Delta launch vehicle in the primary computational grid at a coarse resolution, with subdivided regions at finer resolution being used to pick up the details of the experiment module configuration. Langmuir probe data from the flight were used to estimate the space plasma density and temperature and the Delta ground potential relative to the space plasma. This information is needed for input to NASCAP. Because of the uncertainty or variability in the values of these parameters, it was necessary to explore a range around the nominal value in order to determine the variation in current collection. The flight data from PIX 2 were also compared with the results of the NASCAP simulation.

New markers to identify the provenance of lapis lazuli: trace elements in pyrite by means of micro-PIXE

NASA Astrophysics Data System (ADS)

Re, A.; Angelici, D.; Lo Giudice, A.; Maupas, E.; Giuntini, L.; Calusi, S.; Gelli, N.; Massi, M.; Borghi, A.; Gallo, L. M.; Pratesi, G.; Mandò, P. A.

2013-04-01

Lapis lazuli has been used for glyptics and carving since the fifth millennium BC to produce jewels, amulets, seals, inlays, etc; the identification of the origin of the stone used for carving artworks may be valuable for reconstructing old trade routes. Since ancient lapis lazuli art objects are precious, only non-destructive techniques can be used to identify their provenance, and ion beam analysis (IBA) techniques allow us to characterise this stone in a fully non-invasive way. In addition, by using an ion microprobe, we have been able to focus the analysis on single crystals, as their typical dimensions may range from a few microns to hundreds of microns. Provenance markers, identified in previous IBA studies and already presented elsewhere, were based on the presence/absence of mineral phases, on the presence/quantity of trace elements inside a phase and on characteristic features of the luminescence spectra. In this work, a systematic study on pyrite crystals, a common accessory mineral in lapis lazuli, was carried out, following a multi-technique approach: optical microscopy and SEM-EDX to select crystals for successive trace element micro-PIXE measurements at two Italian facilities, the INFN Laboratori Nazionali di Legnaro and the INFN LABEC laboratory in Firenze. The results of this work allowed us to obtain new markers for lapis lazuli provenance identification.

Regional differences in constituents of gall stones.

PubMed

Ashok, M; Nageshwar Reddy, D; Jayanthi, V; Kalkura, S N; Vijayan, V; Gokulakrishnan, S; Nair, K G M

2005-01-01

The pathogenesis of pigment and mixed gall stone formation remains elusive. The elemental constituents of gall stones from southern states of Tamil Nadu, Kerala and Karnataka have been characterized. Our aim was to determine the elemental concentration of representative samples of pigment, mixed and cholesterol gall stones from Andhra Pradesh using proton-induced X-ray emission (PIXE) using a 3 MV horizontal pelletron accelerator. Pigment gall stones had significantly high concentrations of copper, iron and lead; chromium was absent. Except for iron all these elements were significantly low in cholesterol gall stones and intermediate levels were seen in mixed gall stones. Highest concentrations of chromium was seen in cholesterol and titanium in mixed gall stones respectively; latter similar to other southern states. Arsenic was distinctly absent in cholesterol and mixed gall stones. The study has identified differences in elemental components of the gall stones from Andhra Pradesh.

Elemental composition of airborne dust in the Shale Shaker House during an offshore drilling operation.

PubMed

Hansen, A B; Larsen, E; Hansen, L V; Lyngsaae, M; Kunze, H

1991-12-01

During 2 days of an offshore drilling operation in the North Sea, 16 airborne dust samples from the atmosphere of the Shale Shaker House were collected onto filters. During this operation, drilling mud composed of a water slurry of barite (BaSO4) together with minor amounts of additives, among them chrome lignosulphonate and chrome lignite, was circulated between the borehole and the Shale Shaker House. The concentration of airborne dust in the atmosphere was determined and the elemental composition of the particles analysed by both PIXE (proton-induced X-ray emission) and ICP-MS (inductively coupled plasma-mass spectrometry). The total amount of dust collected varied from 0.04 to 1.41 mg m-3 with barium (Ba) as the single most abundant element. The open shale shakers turned out to be the major cause of generation of dust from the solid components of the drilling mud.

Non-destructive study of iron gall inks in manuscripts

NASA Astrophysics Data System (ADS)

Duh, Jelena; Krstić, Dragica; Desnica, Vladan; Fazinić, Stjepko

2018-02-01

The aim of this research is to establish an effective procedure of iron gall ink characterization using complementary non-destructive methods. By this, it is possible to better understand correlation of chemical composition of the inks and the state of preservation of iron gall ink manuscripts, as well as the effects of conservation treatment performed upon them. This study was undertaken on a bound 16th century manuscript comprised of different types of paper and ink from the National and University Library in Zagreb. Analytical methods used included Particle Induced X-ray Emission (PIXE) and X-ray Fluorescence (XRF). Paper fibers were identified by optical microscopy and the degradation state, as well as ink differentiation, transit metal migrations and detection of stains, with ultraviolet (UV) and infrared (IR) photography. The techniques applied on original writing materials gave important information about paper and ink composition, its preservation state and efficiency of conservation treatment performed upon them.

XRF and micro-PIXE studies of inhomogeneity of ancient bronze and silver alloys

NASA Astrophysics Data System (ADS)

Vasilescu, A.; Constantinescu, B.; Stan, D.; Talmatchi, G.; Ceccato, D.

2017-09-01

New results regarding alloy composition and microstructure for a series of ancient bronze and silver items by X-ray Fluorescence and micro-Particle Induced X-ray Emission spectrometry were obtained in the framework of an extensive numismatic project (Scythian-type arrowheads, arrowhead-shaped monetary signs and wheel coins produced by Histria, 7th-4th century of BCE, and Dacian Radulesti-Hunedoara-type silver tetradrachms, 2nd-1st century of BCE). In Histria, warfare arrowheads were used for trade with Barbarian neighbors at first, then mechanically modified, next melted and cast as dedicated monetary signs, being, in the end, replaced by wheel coins. Three different types of alloys have been identified, and Cu-Mn and Cu-Pb segregation shown. In a blank for Radulesti-Hunedoara-type coins, Ag-(Cu+Pb) segregation has been demonstrated, suggesting an imperfectly alloyed silver-leaded bronze.

Elemental Analysis of Beryllium Samples Using a Microzond-EGP-10 Unit

NASA Astrophysics Data System (ADS)

Buzoverya, M. E.; Karpov, I. A.; Gorodnov, A. A.; Shishpor, I. V.; Kireycheva, V. I.

2017-12-01

Results concerning the structural and elemental analysis of beryllium samples obtained via different technologies using a Microzond-EGP-10 unit with the help of the PIXE and RBS methods are presented. As a result, the overall chemical composition and the nature of inclusions were determined. The mapping method made it possible to reveal the structural features of beryllium samples: to select the grains of the main substance having different size and chemical composition, to visualize the interfaces between the regions of different composition, and to describe the features of the distribution of impurities in the samples.

Deciphering a removed text on a 16th c. centrepiece: The benefits of using AGLAEMap and AXSIA to process PIXE maps.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lemasson, Quentin; Kotula, Paul; Pichon, Laurent

2015-09-01

In the field of archaeometry, it is not uncommon to be presented with art objects that contain inscriptions, signatures and other writings that are nearly impossible to read. Scanned microbeam PIXE offers an attractive approach to attack this problem, but even then the distribution of characteristic X-rays of the element(s) used in these writings can remain illegible. We show in this paper that two methods were used to reveal the inscription: first the use of a GUPIXWin, TRAUPIXE and AGLAEMap software suite enables to make quantitative analysis of each pixel, to visualize the results and to select X-ray peaks thatmore » could enable to distinguish letters. Then, the Automated eXpert Spectral Image Analysis (AXSIA) program developed at Sandia, which analyzes the x-ray intensity vs. Energy and (X, Y) position “datacubes”, was used to factor the datacube into 1) principle component spectral shapes and 2) the weighting images of these components. The specimen selected for this study was a silver plaque representing a scroll from the so-called “MerkelscheTafelaufsatz,” a centrepiece made by the Nuremberg goldsmith Wenzel Jamnitzer in 1549. X-ray radiography of the plaque shows lines of different silver thicknesses, meaning that a text has been removed. The PIXE analysis used a 3-MeV proton beam focused to 50μm and scanned across the sample on different areas of interest of several cm². This analysis showed major elements of Cu and Ag, and minor elements such as Pb, Au, Hg. X-ray intensity maps were then made by setting windows on the various x-ray peaks but the writing on the centrepiece was not revealed even if the map of Cu after data treatment at AGLAE enabled to distinguish some letters. The AXSIA program enabled to factor two main spectral shapes from the datacube that were quite similar and involved virtually all of the X-rays being generated. Nevertheless, small differences between these factors were observed for the Cu K X-rays, Pb, Bi and Au L X-rays. The plot of the factor with the highest Au signal gave also information on the shape of some letters. The comparison of the results obtained by the two methods shows that they both drastically improve the resolution and contrast of such writings and that each of the method can also bring different information on the composition and thus the techniques used for the writing.« less

Energy dependent features of X-ray signals in a GridPix detector

NASA Astrophysics Data System (ADS)

Krieger, C.; Kaminski, J.; Vafeiadis, T.; Desch, K.

2018-06-01

We report on the calibration of an argon/isobutane (97.7%/2.3%)-filled GridPix detector with soft X-rays (277 eV to 8 keV) using the variable energy X-ray source of the CAST Detector Lab at CERN. We study the linearity and energy resolution of the detector using both the number of pixels hit and the total measured charge as energy measures. For the latter, the energy resolution σE / E is better than 10% (20%) for energies above 2 keV (0.5 keV). Several characteristics of the recorded events are studied.

PIXE in experimental archaeometry

NASA Astrophysics Data System (ADS)

Demortier, Guy; Van Oystaeyen, Bruno; Boullar, Annick

1984-04-01

A new step in the understanding of the degree of expertise in soldering in antiquity is discussed. It takes into account results from analyses of noncommercial alloys manufactured with techniques known in early times. The procedure involves only rudimentary means: mixture in a charcoal furnace of gold (or natural gold alloys such as electrum) with a natural cadmium mineral whose colour is close to that of gold and to that of gold solders described in the oldest metallurgical handbooks. PIXE both in nonvacuum and in microprobe arrangements is used to analyse ancient artifacts and soldering alloys of commercial origin and those manufactured by this "ancient procedure."

A GridPix-based X-ray detector for the CAST experiment

NASA Astrophysics Data System (ADS)

Krieger, C.; Kaminski, J.; Lupberger, M.; Desch, K.

2017-09-01

The CAST experiment has been searching for axions and axion-like particles for more than 10 years. The continuous improvements in the detector designs have increased the physics reach of the experiment far beyond what was originally conceived. As part of this development, a new detector based on a GridPix readout had been developed in 2014 and was mounted on the CAST experiment during the end of the data taking period of 2014 and the complete period in 2015. We report on the detector design, its advantages and the performance during both periods.

PIXE Analysis of Metal Hull Bolts From HMB DeBraak

NASA Astrophysics Data System (ADS)

Correll, Francis D.; Cole, Lord K.; Slater, Charles J.; Vanhoy, Jeffrey R.; Fithian, Charles H.

2009-03-01

HMB DeBraak was a 16-gun British brig-sloop that sank in a squall on May 25, 1798 off Cape Henlopen, Delaware. Silt covered the wooden hull shortly after it sank, preserving it until DeBraak was raised in 1986. The items recovered from the ship include metal bolts that held the hull together. We used PIXE to measure the compositions of 45 of the bolts and found that they are nearly pure copper (98.3% on average), with most also containing small amounts of iron (0.87%), nickel (0.039%), arsenic (0.43%), silver (0.089%), lead (0.18%), and bismuth (0.12%). A few contain a little indium, tin, or antimony, but none contain zinc above the quantization level. The compositions are similar to those reported for 18th-century English copper, but different from several copper alloys also used to make hull bolts. We conclude that, when DeBraak was last fitted out in 1795-1797, the Royal Navy was still using bolts similar to William Forbes's mechanically hardened pure copper bolts. Forbes's process represents the successful innovation and application of new technology in Royal Navy ships during the wars of the late 18th century.

Elemental micro-PIXE mapping of hypersensitive lesions in Lagenaria sphaerica (Cucurbitaceae) resistant to Sphaerotheca fuliginea (powdery mildew)

NASA Astrophysics Data System (ADS)

Weiersbye-Witkowski, I. M.; Przybylowicz, W. J.; Straker, C. J.; Mesjasz-Przybylowicz, J.

1997-07-01

Genotypes of the Southern African cucurbit, Lagenaria sphaerica, that are resistant to powdery-mildew ( Sphaerotheca fuliginea) exhibit foliar hypersensitive (HS) lesions on inoculation with this fungal pathogen. Elemental distributions across radially symmetrical HS lesions, surrounding unlesioned leaf tissue and uninoculated leaf tissue, were obtained using the true elemental imaging system (Dynamic Analysis) of the NAC Van de Graaff nuclear microprobe. Raster scans of 3 MeV protons were complemented by simultaneous PIXE and BS point analyses. The composition of cellulose (C 6H 10O 5) was used as constant matrix composition for scans, and the sample thickness was found from BS spectra. Si and elements heavier than Ca contributed to matrix composition within HS lesions and the locally elevated Ca raised the limits of detection for some trace metals of interest. In comparison to uninoculated tissue, inoculated tissue was characterised by higher overall concentrations of all measured elements except Cu. Fully developed, 6 day-old HS lesions and the surrounding tissue could be divided into five zones, centred on the fungal infection site. Each zone was characterized by distinct local elemental distributions (either depletion, or accumulation to potentially phytotoxic levels).

Trace elemental analysis in cancer-afflicted tissues of penis and testis by PIXE technique

NASA Astrophysics Data System (ADS)

Naga Raju, G. J.; John Charles, M.; Bhuloka Reddy, S.; Sarita, P.; Seetharami Reddy, B.; Rama Lakshmi, P. V. B.; Vijayan, V.

2005-04-01

PIXE technique was employed to estimate the trace elemental concentrations in the biological samples of cancerous penis and testis. A 3 MeV proton beam was employed to excite the samples. From the present results it can be seen that the concentrations of Cl, Fe and Co are lower in the cancerous tissue of the penis when compared with those in normal tissue while the concentrations of Cu, Zn and As are relatively higher. The concentrations of K, Ca, Ti, Cr, Mn, Br, Sr and Pb are in agreement within standard deviations in both cancerous and normal tissues. In the cancerous tissue of testis, the concentrations of K, Cr and Cu are higher while the concentrations of Fe, Co and Zn are lower when compared to those in normal tissue of testis. The concentrations of Cl, Ca, Ti and Mn are in agreement in both cancerous and normal tissues of testis. The higher levels of Cu lead to the development of tumor. Our results also support the underlying hypothesis of an anticopper, antiangiogenic approach to cancer therapy. The Cu/Zn ratios of both penis and testis were higher in cancer tissues compared to that of normal.

Copper, zinc, gallium and germanium distributions in taenite lamellae of iron meteorites and their importance for cooling rate estimations

NASA Astrophysics Data System (ADS)

Braun-Dullaeus, Karl-Ulrich; Traxel, Kurt

1995-02-01

One method forestimating cooling rates of meteorite parent bodies is to model measured nickel distributions in taenite lamellae of iron meteorites. Goldstein and Ogilvie ( Geochim. Cosmochim. Acta29, 893, 1965) and Rasmussen ( Icarus45, 564, 1981) developed techniques based on this idea to examine the cooling history in the temperature range between ˜700 and ˜400°C. As a result of Instrumental Neutron Activation Analysis (INAA) Rasmussen et al. ( Meteoritics23, 105, 1988) postulated that some trace elements would also be good cooling rate indicators. They argued that elements with distinct diffusion behavior are sensitive to different temperature ranges. The new Heidelberg proton microprobe uses the method of Proton Induced X-ray Emission (PIXE) for elemental analysis. This microprobe is an appropriate instrument to measure distributions of trace elements with a spatial resolution of 2 μm. We demonstrated on the iron meteorites Cape York (Agpalilik), Toluca and Odessa that the elements copper, zinc, gallium and germanium imitate the profiles of nickel in taenite lamella. The interpretation of the Zn, Ga and Ge profiles leads to the conclusion that these elements undergo diffusion mechanisms comparable to those of Ni. The numerical simulation of Cu distributions with a simplified model points out that little new information can be obtained about the cooling history of the meteorites by modelling Cu profiles. To simulate Zn, Ga or Ge distributions, the use of ternary phase diagrams is necessary.

Study of the chemical elements and polycyclic aromatic hydrocarbons in atmospheric particles of PM 10 and PM 2.5 in the urban and rural areas of South Brazil

NASA Astrophysics Data System (ADS)

Dallarosa, Juliana; Calesso Teixeira, Elba; Meira, Lindolfo; Wiegand, Flavio

2008-07-01

The purpose of this work is to study the chemical elements and PAHs associated with atmospheric particulate in samples of PM 10 collected in the Metropolitan Area of Porto Alegre—MAPA, Rio Grande do Sul, Brazil. In addition, to study the chemical elements associated with particles of different fractions of PM 10-2.5 and PM 2.5 using dichotomous sampling, in urban (MAPA) and rural areas. Two types of samplers were used: HV PM 10 and Dichotomous (PM 10-2.5 and PM 2.5). Samples were collected during 2002 and 2005. The concentration of the elements Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, and Zn was determined by PIXE (Particle-Induced X-ray Emission), while the concentrations of 16 major PAHs were determined according to EPA with a gas chromatograph coupled to a mass spectrometer (GS/MS). Results showed that elements of anthropogenic origin (V, Zn, Cr, Ni, Cu, and S) were mainly associated with the fraction PM 2.5, while the soil dust (Si, Al, Ti and Fe) were found mainly on fraction PM 10-2.5. In samples of PM 10, the most frequent PAHs found were Bgp, Flt, BaA, Chr, B(b + k)F, BaP and Dba. The types of emission and their association with the atmospheric parameters were studied applying the statistical analysis of the principal component method. The main sources found in the area under study were vehicles, industries (steel mills and a coal-fired power station), dust, sea breeze, and burning.

Two VLT 8.2-m Unit Telescopes in Action

NASA Astrophysics Data System (ADS)

1999-04-01

Visitors at ANTU - Astronomical Images from KUEYEN The VLT Control Room at the Paranal Observatory is becoming a busy place indeed. From here, two specialist teams of ESO astronomers and engineers now operate two VLT 8.2-m Unit Telescopes in parallel, ANTU and KUEYEN (formerly UT1 and UT2, for more information about the naming and the pronunciation, see ESO Press Release 06/99 ). Regular science observations have just started with the first of these giant telescopes, while impressive astronomical images are being obtained with the second. The work is hard, but the mood in the control room is good. Insiders claim that there have even been occasions on which the groups have had a friendly "competition" about which telescope makes the "best" images! The ANTU-team has worked with the FORS multi-mode instrument , their colleagues at KUEYEN use the VLT Test Camera for the ongoing tests of this new telescope. While the first is a highly developed astronomical instrument with a large-field CCD imager (6.8 x 6.8 arcmin 2 in the normal mode; 3.4 x 3.4 arcmin 2 in the high-resolution mode), the other is a less complex CCD camera with a smaller field (1.5 x 1.5 arcmin 2 ), suited to verify the optical performance of the telescope. As these images demonstrate, the performance of the second VLT Unit Telescope is steadily improving and it may not be too long before its optical quality will approach that of the first. First KUEYEN photos of stars and galaxies We present here some of the first astronomical images, taken with the second telescope, KUEYEN, in late March and early April 1999. They reflect the current status of the optical, electronic and mechanical systems, still in the process of being tuned. As expected, the experience gained from ANTU last year has turned out to be invaluable and has allowed good progress during this extremely delicate process. ESO PR Photo 19a/99 ESO PR Photo 19a/99 [Preview - JPEG: 400 x 433 pix - 160k] [Normal - JPEG: 800 x 866 pix - 457k] [High-Res - JPEG: 1985 x 2148 pix - 2.0M] ESO PR Photo 19b/99 ESO PR Photo 19b/99 [Preview - JPEG: 400 x 478 pix - 165k] [Normal - JPEG: 800 x 956 pix - 594k] [High-Res - JPEG: 3000 x 3583 pix - 7.1M] Caption to PR Photo 19a/99 : This photo was obtained with VLT KUEYEN on April 4, 1999. It is reproduced from an excellent 60-second R(ed)-band exposure of the innermost region of a globular cluster, Messier 68 (NGC 4590) , in the southern constellation Hydra (The Water-Snake). The distance to this 8-mag cluster is about 35,000 light years, and the diameter is about 140 light-years. The excellent image quality is 0.38 arcsec , demonstrating a good optical and mechanical state of the telescope, already at this early stage of the commissioning phase. The field measures about 90 x 90 arcsec 2. The original scale is 0.0455 pix/arcsec and there are 2048x2048 pixels in one frame. North is up and East is left. Caption to PR Photo 19b/99 : This photo shows the central region of spiral galaxy ESO 269-57 , located in the southern constellation Centaurus at a distance of about 150 million light-years. Many galaxies are seen in this direction at about the same distance, forming a loose cluster; there are also some fainter, more distant ones in the background. The designation refers to the ESO/Uppsala Survey of the Southern Sky in the 1970's during which over 15,000 southern galaxies were catalogued. ESO 269-57 is a tightly bound object of type Sar , the "r" referring to the "ring" that surrounds the bright centre, that is overexposed here. The photo is a composite, based on three exposures (Blue - 600 sec; Yellow-Green - 300 sec; Red - 300 sec) obtained with KUEYEN on March 28, 1999. The image quality is 0.7 arcsec and the field is 90 x 90 arcsec 2. North is up and East is left. ESO PR Photo 19c/99 ESO PR Photo 19c/99 [Preview - JPEG: 400 x 478 pix - 132k] [Normal - JPEG: 800 x 956 pix - 446k] [High-Res - JPEG: 3000 x 3583 pix - 4.6M] ESO PR Photo 19d/99 ESO PR Photo 19d/99 [Preview - JPEG: 400 x 454 pix - 86k] [Normal - JPEG: 800 x 907 pix - 301k] [High-Res - JPEG: 978 x 1109 pix - 282k] Caption to PR Photo 19c/99 : Somewhat further out in space, and right on the border between the southern constellations Hydra and Centaurus lies this knotty spiral galaxy, IC 4248 ; the distance is about 210 million light-years. It was imaged with KUEYEN on March 28, 1999, with the same filters and exposure times as used for Photo 19b/99. The image quality is 0.75 arcsec and the field is 90 x 90 arcsec 2. North is up and East is left. Caption to PR Photo 19d/99 : This is a close-up view of the double galaxy NGC 5090 (right) and NGC 5091 (left), in the southern constellation Centaurus. The first is a typical S0 galaxy with a bright diffuse centre, surrounded by a fainter envelope of stars (not resolved in this picture). However, some of the starlike objects seen in this region may be globular clusters (or dwarf galaxies) in orbit around NGC 5090. The other galaxy is of type Sa (the spiral structure is more developed) and is seen at a steep angle. The three-colour composite is based on frames obtained with KUEYEN on March 29, 1999, with the same filters and exposure times as used for Photo 19b/99. The image quality is 0.7 arcsec and the field is 90 x 90 arcsec 2. North is up and East is left. ( Note inserted on April 26: The original caption text identified the second galaxy as NGC 5090B - this error has now been corrected. ESO PR Photo 19e/99 ESO PR Photo 19e/99 [Preview - JPEG: 400 x 441 pix - 282k] [Normal - JPEG: 800 x 882 pix - 966k] [High-Res - JPEG: 3000 x 3307 pix - 6,4M] Caption to PR Photo 19e/99 : Wide-angle photo of the second 8.2-m VLT Unit Telescope, KUEYEN , obtained on March 10, 1999, with the main mirror and its cell in place at the bottom of the telescope structure. The Test Camera with which the astronomical images above were made, is positioned at the Cassegrain focus, inside this mirror cell. The Paranal Inauguration on March 5, 1999, took place under this telescope that was tilted towards the horizon to accommodate nearly 300 persons on the observing floor. Astronomical observations with ANTU have started On April 1, 1999, the first 8.2-m VLT Unit Telescope, ANTU , was "handed over" to the astronomers. Last year, about 270 observing proposals competed about the first, precious observing time at Europe's largest optical telescope and more than 100 of these were accommodated within the six-month period until the end of September 1999. The complete observing schedule is available on the web. These observations will be carried out in two different modes. During the Visitor Mode , the astronomers will be present at the telescope, while in the Service Mode , ESO observers perform the observations. The latter procedure allows a greater degree of flexibility and the possibility to assign periods of particularly good observing conditions to programmes whose success is critically dependent on this. The first ten nights at ANTU were allocated to service mode observations. After some initial technical problems with the instruments, these have now started. Already in the first night, programmes at ISAAC requiring 0.4 arcsec conditions could be satisfied, and some images better than 0.3 arcsec were obtained in the near-infrared . The first astronomers to use the telescope in visitors mode will be Professors Immo Appenzeller (Heidelberg, Germany; "Photo-polarimetry of pulsars") and George Miley (Leiden, The Netherlands; "Distant radio galaxies") with their respective team colleagues. How to obtain ESO Press Information ESO Press Information is made available on the World-Wide Web (URL: http://www.eso.org../ ). ESO Press Photos may be reproduced, if credit is given to the European Southern Observatory. Note also the dedicated webarea with VLT Information.

The Use of Ion Implantation for Materials Processing.

DTIC Science & Technology

1983-09-28

SPUTTERING ANALYSIS WITH PIXE.......................... 31 J.M. Lambert, P.A. Treado, D . Trbojevic ,2 R.G. Alias, A.R. Knudson, G.W. Reynolds and F.R...Lambert and P. . Treado I D . Trbojevic R. G. Allas and A. R. Knudson 3 G. W. Reynolds and F. R. Vozzo 4 IGeorgetown University Washington, D . C. and...D.C. 20057 and 20375 D . Trbojevic Georgetown University, Washington, D.C. 20057 R.G. Alias and A.R. Knudson Naval Research Laboratory, Washington, D.C

Detection and Dynamic Analysis of Space Debris in the Geo Ring

NASA Astrophysics Data System (ADS)

Lacruz, E.; Abad, C.; Downes, J. J.; Casanova, D.; Tresaco, E.

2018-01-01

There are different populations of space debris (SD) in the geostationary (GEO) region. It is of great interest to know their dynamics, in order to contribute to aspects such as alerts against possible collisions, repositioning of GEO satellites or placing those satellites that come into service. In this contribution we present a study about the detection and dynamic analysis of SD located in the GEO ring. Using the telescopes of the Venezuelan Obseratory National (VON), a large amount of astrometric observations have been acquired. A preliminary dynamic analysis of them has been carried out, which evidences the average relative motion of these orbiters with a mean absolute error for coordinates of ≍ 0.09 pix.

Micro-PIXE studies of elemental distribution in Cd-accumulating Brassica juncea L.

NASA Astrophysics Data System (ADS)

Schneider, Thorsten; Haag-Kerwer, Angela; Maetz, Mischa; Niecke, Manfred; Povh, Bogdan; Rausch, Thomas; Schüßler, Arthur

1999-10-01

Brassica juncea L. is a high biomass producing crop plant, being able to accumulate Cd and other heavy metals in their roots and shoots. It is a good candidate for efficient phytoextraction of heavy metals - such as Cd - from polluted soils. PIXE and STIM analyses were applied to investigate Cd-uptake in roots and the resulting effects on the elemental distribution of Cd stressed plants. The axial distribution of trace elements as a function of distance from the root tip as well as the radial distribution within cross-sections were analysed. The results are compared with the elemental distribution in control plants.

VizieR Online Data Catalog: Variables in Centaurus field F170 (Pietrukowicz+, 2012)

NASA Astrophysics Data System (ADS)

Pietrukowicz, P.; Minniti, D.; Alonso-Garcia; J.; Hempel, M.

2011-10-01

VJHKs photometry of stars in two VIMOS disc fields: F167 and F170. Data table with 333 variables detected in the field F170 in Centaurus. The optical observations were taken with the 8.2-m Unit Telescope 3 + VIMOS imager with a scale of 0.205"/pix at ESO Very Large Telescope at Paranal Observatory. Date of the observations: Apr 11-12, 2005. The infrared observations were obtained with the 4.1-m VISTA telescope + VIRCAM with a scale of 0.34"/pix also at Paranal Observatory. Date of the observations: Mar-Apr 2010. (4 data files).

Next generation phage display by use of pVII and pIX as display scaffolds.

PubMed

Løset, Geir Åge; Sandlie, Inger

2012-09-01

Phage display technology has evolved to become an extremely versatile and powerful platform for protein engineering. The robustness of the phage particle, its ease of handling and its ability to tolerate a range of different capsid fusions are key features that explain the dominance of phage display in combinatorial engineering. Implementation of new technology is likely to ensure the continuation of its success, but has also revealed important short comings inherent to current phage display systems. This is in particular related to the biology of the two most popular display capsids, namely pIII and pVIII. Recent findings using two alternative capsids, pVII and pIX, located to the phage tip opposite that of pIII, suggest how they may be exploited to alleviate or circumvent many of these short comings. This review addresses important aspects of the current phage display standard and then discusses the use of pVII and pIX. These may both complement current systems and be used as alternative scaffolds for display and selection to further improve phage display as the ultimate combinatorial engineering platform. Copyright © 2012 Elsevier Inc. All rights reserved.

Shadow of a Large Disc Casts New Light on the Formation of High Mass Stars

NASA Astrophysics Data System (ADS)

2004-05-01

Massive Star Observed that Forms through a Rotating Accretion Disc Summary Based on a large observational effort with different telescopes and instruments, mostly from the European Southern Observatory (ESO), a team of European astronomers [1] has shown that in the M 17 nebula a high mass star [2] forms via accretion through a circumstellar disc, i.e. through the same channel as low-mass stars. To reach this conclusion, the astronomers used very sensitive infrared instruments to penetrate the south-western molecular cloud of M 17 so that faint emission from gas heated up by a cluster of massive stars, partly located behind the molecular cloud, could be detected through the dust. Against the background of this hot region a large opaque silhouette, which resembles a flared disc seen nearly edge-on, is found to be associated with an hour-glass shaped reflection nebula. This system complies perfectly with a newly forming high-mass star surrounded by a huge accretion disc and accompanied by an energetic bipolar mass outflow. The new observations corroborate recent theoretical calculations which claim that stars up to 40 times more massive than the Sun can be formed by the same processes that are active during the formation of stars of smaller masses. PR Photo 15a/04: Stellar cluster and star-forming region M 17 (also available without text inside photo) PR Photo 15b/04: Silhouette disc seen in M 17 PR Photo 15c/04: Rotation of the disc in M 17. PR Photo 15d/04: Bipolar reflection nebula and silhouette disc of a young, massive star in M 17 PR Photo 15e/04: Optical spectrum of the bipolar nebula. PR Video 03/04: Zooming in onto the disc. The M 17 region ESO PR Photo 15a/04 ESO PR Photo 15a/04 [Preview - JPEG: 400 x 497 pix - 271k] [Normal - JPEG: 800 x 958 pix - 604k] ESO PR Photo 15a1/04 ESO PR Photo 15a/04 (without text within photo) [Preview - JPEG: 400 x 480 pix - 275k] [Normal - JPEG: 800 x 959 pix - 634k] [High-Res - JPEG: 3000 x 3597 pix - 3.8M] [Full-Res - JPEG: 3815 x 4574 pix - 5.4M] Caption: PR Photo 15a/04 is a reproduction of a three-colour composite of the sky region of M 17, a H II region excited by a cluster of young, hot stars. A large silhouette disc has been found to the south-west of the cluster centre. The area within the indicated square is shown in more detail in PR Photo 15b/04. The present image was obtained with the ISAAC near-infrared instrument at the 8.2-m VLT ANTU telescope at Paranal. In the left photo, the orientation and the scale at the distance of M 17 (7,000 light-years) are indicated, and the main regions are identified. To the right, this beautiful photo is available without text and in full resolution for reproduction purposes. While many details related to the formation and early evolution of low-mass stars like the Sun are now well understood, the basic scenario that leads to the formation of high-mass stars [2] still remains a mystery. Two possible scenarios for the formation of massive stars are currently being studied. In the first, such stars form by accretion of large amounts of circumstellar material; the infall onto the nascent star varies with time. Another possibility is formation by collision (coalescence) of protostars of intermediate masses, increasing the stellar mass in "jumps". In their continuing quest to add more pieces to the puzzle and help providing an answer to this fundamental question, a team of European astronomers [1] used a battery of telescopes, mostly at two of the European Southern Observatory's Chilean sites of La Silla and Paranal, to study in unsurpassed detail the Omega nebula. The Omega nebula, also known as the 17th object in the list of famous French astronomer Charles Messier, i.e. Messier 17 or M 17, is one of the most prominent star forming regions in our Galaxy. It is located at a distance of 7,000 light-years. M 17 is extremely young - in astronomical terms - as witnessed by the presence of a cluster of high-mass stars that ionise the surrounding hydrogen gas and create a so-called H II region. The total luminosity of these stars exceeds that of our Sun by almost a factor of ten million. Adjacent to the south-western edge of the H II region, there is a huge cloud of molecular gas which is believed to be a site of ongoing star formation. In order to search for newly forming high-mass stars, Rolf Chini of the Ruhr-Universität Bochum (Germany) and his collaborators have recently investigated the interface between the H II region and the molecular cloud by means of very deep optical and infrared imaging between 0.4 and 2.2 µm. This was done with ISAAC (at 1.25, 1.65 and 2.2 µm) at the ESO Very Large Telescope (VLT) on Cerro Paranal in September 2002 and with EMMI (at 0.45, 0.55, 0.8 µm) at the ESO New Technology Telescope (NTT), La Silla, in July 2003. The image quality was limited by atmospheric turbulence and varied between 0.4 and 0.8 arcsec. The result of these efforts is shown in PR Photo 15a/04. Rolf Chini is pleased: "Our measurements are so sensitive that the south-western molecular cloud of M 17 is penetrated and the faint nebular emission of the H II region, which is partly located behind the molecular cloud, could be detected through the dust." Against the nebular background of the H II region a large opaque silhouette is seen associated with an hourglass shaped reflection nebula. The silhouette disc ESO PR Photo 15b/04 ESO PR Photo 15b/04 [Preview - JPEG: 400 x 475 pix - 348k] [Normal - JPEG: 800 x 950 pix - 907k] Caption: PR Photo 15b/04 shows a Ks-band image of the silhouette disc obtained with the NACO Adaptive Optics camera at the 8.2-m VLT YEPUN telescope at Paranal. The displayed field-of-view is outlined in PR Photo 15a/04. White contours delineate the densest part of the disc (inner torus). The visible stars (slightly elongated due to the adaptive optics technique) are embedded within the molecular cloud but are probably unrelated to the disc. The insert shows a deconvolved zoomed version of the central object of about 450 x 240 AU; its major axis is tilted by about 15 degrees against the direction perpendicular to the disc. ESO PR Video Clip 03/04 ESO PR Video Clip 03/04 [QuickTime Video+Audio; 160x120 pix; 18Mb] Caption: PR Video Clip 03/04 zooms in towards the disc, starting from the ISAAC image of the full nebula to the NACO image of the silhouette disc. This shows the remarkable power of the set of instruments on the Very Large Telescope. ESO PR Photo 15c/04 ESO PR Photo 15c/04 [Preview - JPEG: 533 x 400 pix - 80k] [Normal - JPEG: 1067 x 800 pix - 185k] Caption: PR Photo 15c/04 Position-velocity diagram revealing the rotation of the disc. It is derived from a cut along the major axis of the disc, using the IRAM Plateau de Bure interferometer. For comparison, the theoretically expected position-velocity curve for an edge-on disc around a star of 15 solar masses is shown, the outer part of which (radii larger than about 15,400 AU) is in Keplerian rotation while its inner part is modeled as a rigid rotator. To obtain a better view of the structure, the team of astronomers turned then to Adaptive Optics imaging using the NAOS-CONICA instrument on the VLT. Adaptive optics is a "wonder-weapon" in ground-based astronomy, allowing astronomers to "neutralize" the image-smearing turbulence of the terrestrial atmosphere (seen by the unaided eye as the twinkling of stars) so that much sharper images can be obtained. With NAOS-CONICA on the VLT, the astronomers were able to obtain images with a resolution better than one tenth of the "seeing", that is, as what they could observe with ISAAC. PR Photo 15b/04 shows the high-resolution near-infrared (2.2 µm) image they obtained. It clearly suggests that the morphology of the silhouette resembles a flared disc, seen nearly edge-on. The disc has a diameter of about 20,000 AU [3] - which is 500 times the distance of the farthest planet in our solar system - and is by far the largest circumstellar disc ever detected. To study the disc structure and properties, the astronomers then turned to radio astronomy and carried out molecular line spectroscopy at the IRAM Plateau de Bure interferometer near Grenoble (France) in April 2003. The astronomers have observed the region in the rotational transitions of the 12CO, 13CO and C18O molecules, and in the adjacent continuum at 3 mm. Velocity resolutions of 0.1 and 0.2 km/s, respectively, were achieved. Dieter Nürnberger, member of the team, sees this as a confirmation: "Our 13CO data obtained with IRAM indicate that the disc/envelope system slowly rotates with its north-western part approaching the observer." Over an extent of 30,800 AU a velocity shift of 1.7 km/s is indeed measured (PR Photo 15c/04). From these observations, adopting standard values for the abundance ratio between the different isotopic carbon monoxide molecules (12CO and 13CO) and for the conversion factor to derive molecular hydrogen densities from the mesured CO intensities, the astronomers were also able to derive a conservative lower limit for the disc mass of 110 solar masses. This is by far the most massive and largest accretion disc ever observed directly around a young massive star. The largest silhouette disc so far is known as 114-426 in Orion and has a diameter of about 1,000 AU; however, its central star is likely a low-mass object rather than a massive protostar. Although there are a small number of candidates for massive young stellar objects (YSOs) some of which are associated with outflows, the largest circumstellar disc hitherto detected around these objects has a diameter of only 130 AU. The bipolar nebula ESO PR Photo 15d/04 ESO PR Photo 15d/04 [Preview - JPEG: 450 x 400 pix - 119k] [Normal - JPEG: 913 x 800 pix - 272k] Caption: PR Photo 15d/04 displays a collection of images of the silhouette disc and, perpendicular to that, the bipolar reflection nebula. These images were obtained in different optical and near-infrared wavebands with different instruments: EMMI at the ESO New Technology Telescope on La Silla (top row; wavelengths 0.45 [B-band], 0.55 [V-band], 0.8 µm [I-band], respectively) and ISAAC at the ESO Very Large Telescope on Cerro Paranal (bottom row; 1.25 [J], 1.65 [H] and 2.2 µm [K]). All images are centred on the central massive protostar and cover an area of 30 x 30 arcsec2, corresponding to 1.0 x 1.0 light-years2 at the distance of M 17 (about 7,000 light-years). The obscuration diminishes with increasing wavelength and the background emission of the H II region becomes more and more evident (represented by entirely black colours at K). ESO PR Photo 15e/04 ESO PR Photo 15e/04 [Preview - JPEG: 757 x 400 pix - 136k] [Normal - JPEG: 1513 x 800 pix - 311k] Caption: PR Photo 15e/04 shows an optical spectrum of the bipolar nebula, obtained with EFOSC2 at the ESO 3.6 m telescope and with EMMI at the ESO 3.5 m NTT, both located on La Silla, Chile. A number of identified emission lines, like Hα and the Ca II triplet 849.8, 854.2 and 866.2 nm, are denoted. The second morphological structure that is visible on all images throughout the entire spectral range from visible to infrared (0.4 to 2.2 µm) is an hourglass-shaped nebula perpendicular to the plane of the disc (PR Photo 15d/04). This is believed to be an energetic outflow coming from the central massive object. To confirm this, the astronomers went back to ESO's telescopes to perform spectroscopic observations. The optical spectra of the bipolar outflow were measured in April/June 2003 with EFOSC2 at the ESO 3.6 m telescope and with EMMI at the ESO 3.5 m NTT, both located on La Silla, Chile. The observed spectrum (PR Photo 15e/04) is dominated by the emission lines of hydrogen (Hα), calcium (the Ca II triplet 849.8, 854.2 and 866.2 nm), and helium (He I 667.8 nm). In the case of low-mass stars, these lines provide indirect evidence for ongoing accretion from the inner disc onto the star. The Ca II triplet was also shown to be a product of disc accretion for both a large sample of low and intermediate-mass protostars, known as T Tauri and Herbig Ae/Be stars, respectively. Moreover, the Hα line is extremely broad and shows a deep blue-shifted absorption typically associated with accretion disc-driven outflows. In the spectrum, numerous iron (Fe II) lines were also observed, which are velocity-shifted by ± 120 km/s. This is clear evidence for the existence of shocks with velocities of more than 50 km/s, hence another confirmation of the outflow hypothesis. The central protostar Due to heavy extinction, the nature of an accreting protostellar object, i.e. a star in the process of formation, is usually difficult to infer. Accessible are only those that are located in the neighbourhood of their elder brethren, e.g. next to a cluster of hot stars (cf. ESO PR 15/03). Such already evolved massive stars are a rich source of energetic photons and produce powerful stellar winds of protons (like the "solar wind" but much stronger) which impact on the surrounding interstellar gas and dust clouds. This process may lead to partial evaporation and dispersion of those clouds, thereby "lifting the curtain" and allowing us to look directly at young stars in that region. However, for all high-mass protostellar candidates located away from such a hostile environment there is not a single direct evidence for a (proto-)stellar central object; likewise, the origin of the luminosity - typically about ten thousand solar luminosities - is unclear and may be due to multiple objects or even embedded clusters. The new disc in M 17 is the only system which exhibits a central object at the expected position of the forming star. The 2.2 µm emission is relatively compact (240 AU x 450 AU) - too small to host a cluster of stars. Assuming that the emission is due solely to the star, the astronomers derive an absolute infrared brightness of about K = -2.5 magnitudes which would correspond to a main sequence star of about 20 solar masses. Given the fact that the accretion process is still active, and that models predict that about 30-50% of the circumstellar material can be accumulated onto the central object, it is likely that in the present case a massive protostar is currently being born. Theoretical calculations show that an initial gas cloud of 60 to 120 solar masses may evolve into a star of approximately 30-40 solar masses while the remaining mass is rejected into the interstellar medium. The present observations may be the first to show this happening.

Identification and quantitive analysis of calcium phosphate microparticles in intestinal tissue by nuclear microscopy

NASA Astrophysics Data System (ADS)

Gomez-Morilla, Inmaculada; Thoree, Vinay; Powell, Jonathan J.; Kirkby, Karen J.; Grime, Geoffrey W.

2006-08-01

Microscopic particles (0.5-2 μm diameter), rich in calcium and phosphorus, are found in the lumen of the mid-distal gut of all mammals investigated, including humans, and these may play a role in immuno-surveillance and immune regulation of antigens from food and symbiotic bacteria that are contained in the gut. Whether these particles can cross in to tissue of the intestinal mucosa is unclear. If so, characterising their morphology and chemical composition is an important task in elucidating their function. The analysis of calcium phosphate in biological tissues has been approached in several ways including optical microscopy, scanning electron microscopy and, most recently in this work, with nuclear microscopy. In this paper, we describe the use of microPIXE and microRBS to locate these particles and to determine, accurately, the ratio of phosphorus to calcium using the information on sample thickness obtained from RBS to allow the PIXE ratios to be corrected. A commercial sample of hydroxy apatite was used to demonstrate accuracy and precision of the technique. Then, in a pilot study on intestinal tissue of mice, we demonstrated the presence of calcium phosphate microparticles, consistent with confocal microscopy observations, and we identified the average molar P:Ca molar ratio as 1.0. Further work will confirm the exact chemical speciation of these particles and will examine the influence of differing calcium containing diets on the formation of these microparticles.

Ion Beam Analyses Of Bark And Wood In Environmental Studies

NASA Astrophysics Data System (ADS)

Lill, J.-O.; Saarela, K.-E.; Harju, L.; Rajander, J.; Lindroos, A.; Heselius, S.-J.

2011-06-01

A large number of wood and bark samples have been analysed utilizing particle-induced X-ray emission (PIXE) and particle-induced gamma-ray emission (PIGE) techniques. Samples of common tree species like Scots Pine, Norway Spruce and birch were collected from a large number of sites in Southern and Southwestern Finland. Some of the samples were from a heavily polluted area in the vicinity of a copper-nickel smelter. The samples were dry ashed at 550 °C for the removal of the organic matrix in order to increase the analytical sensitivity of the method. The sensitivity was enhanced by a factor of 50 for wood and slightly less for bark. The ashed samples were pressed into pellets and irradiated as thick targets with a millimetre-sized proton beam. By including the ashing procedure in the method, the statistical dispersion due to elemental heterogeneities in wood material could be reduced. As a by-product, information about the elemental composition of ashes was obtained. By comparing the concentration of an element in bark ash to the concentration in wood ash of the same tree useful information from environmental point of view was obtained. The obtained ratio of the ashes was used to distinguish between elemental contributions from anthropogenic atmospheric sources and natural geochemical sources, like soil and bedrock.

"First Light" for HARPS at La Silla

NASA Astrophysics Data System (ADS)

2003-03-01

"First Light" for HARPS at La Silla Advanced Planet-Hunting Spectrograph Passes First Tests With Flying Colours Summary The initial commissioning period of the new HARPS spectrograph (High Accuracy Radial Velocity Planet Searcher) of the 3.6-m telescope at the ESO La Silla Observatory has been successfully accomplished in the period February 11 - 27, 2003. This new instrument is optimized to detect planets in orbit around other stars ("exoplanets") by means of accurate (radial) velocity measurements with an unequalled precision of 1 meter per second . This high sensitivity makes it possible to detect variations in the motion of a star at this level, caused by the gravitational pull of one or more orbiting planets, even relatively small ones. "First Light" occurred on February 11, 2003, during the first night of tests. The instrument worked flawlessly and was fine-tuned during subsequent nights, achieving the predicted performance already during this first test run. The measurement of accurate stellar radial velocities is a very efficient way to search for planets around other stars. More than one hundred extrasolar planets have so far been detected , providing an increasingly clear picture of a great diversity of exoplanetary systems . However, current technical limitations have so far prevented the discovery around solar-type stars of exoplanets that are much less massive than Saturn, the second-largest planet in the solar system. HARPS will break through this barrier and will carry this fundamental exploration towards detection of exoplanets with masses like Uranus and Neptune. Moreover, in the case of low-mass stars - like Proxima Centauri, cf. ESO PR 05/03 - HARPS will have the unique capability to detect big "telluric" planets with only a few times the mass of the Earth . The HARPS instrument is being offered to the research community in the ESO member countries, already from October 2003 . PR Photo 08a/03 : The large optical grating of the HARPS spectrograph . PR Photo 08b/03 : The HARPS spectrograph . PR Photo 08c/03 : HARPS spectrum of the star HD100623 ("raw"). PR Photo 08d/03 : Extracted spectral tracing of the star HD100623 . PR Photo 08e/03 : Measured stability of HARPS. The HARPS Spectrograph ESO PR Photo 08a/03 ESO PR Photo 08a/03 [Preview - JPEG: 449 x 400 pix - 58k [Normal - JPEG: 897 x 800 pix - 616k] [Full-Res - JPEG: 1374 x 1226 pix - 1.3M] ESO PR Photo 08b/03 ESO PR Photo 08b/03 [Preview - JPEG: 500 x 400 pix - 83k [Normal - JPEG: 999 x 800 pix - 727k] [Full-Res - JPEG: 1600 x 1281 pix - 1.3M] Captions : PR Photo 08a/03 and PR Photo 08b/03 show the HARPS spectrograph during laboratory tests. The vacuum tank is open so that some of the high-precision components inside can be seen. On PR Photo 08a/03 , the large optical grating by which the incoming stellar light is dispersed is visible on the top of the bench; it measures 200 x 800 mm. HARPS is a unique fiber-fed "echelle" spectrograph able to record at once the visible range of a stellar spectrum (wavelengths from 380 - 690 nm) with very high spectral resolving power (better than R = 100,000 ). Any light losses inside the instrument caused by reflections of the starlight in the various optical components (mirrors and gratings), have been minimised and HARPS therefore works very efficiently . First observations ESO PR Photo 08c/03 ESO PR Photo 08c/03 [Preview - JPEG: 400 x 490 pix - 52k [Normal - JPEG: 800 x 980 pix - 362k] [Full-Res - JPEG: 1976 x 1195 pix - 354k] ESO PR Photo 08d/03 ESO PR Photo 08d/03 [Preview - JPEG: 485 x 400 pix - 53k [Normal - JPEG: 969X x 800 pix - 160k] Captions : PR Photo 08c/03 displays a HARPS untreated ("raw") exposure of the star HD100623 , of the comparatively cool stellar spectral type K0V. The frame shows the complete image as recorded with the 4000 x 4000 pixel CCD detector in the focal plane of the spectrograph. The horizontal white lines correspond to the stellar spectrum, divided into 70 adjacent spectral bands which together cover the entire visible wavelength range from 380 to 690 nm. Some of the stellar absorption lines are seen as dark horizontal features; they are the spectral signatures of various chemical elements in the star's upper layers ("atmosphere"). Bright emission lines from the heavy element thorium are visible between the bands - they are exposed by a lamp in the spectrograph to calibrate the wavelengths. This allows measuring any instrumental drift, thereby guaranteeing the exceedingly high precision that qualifies HARPS. PR Photo 08d/03 displays a small part of the spectrum of the star HD100623 following on-line data extraction (in astronomical terminology: "reduction") of the previous raw frame, shown in PR Photo 08c/03 . Several deep absorption lines are clearly visible. During the first commissioning period in February 2003, the high efficiency of HARPS was clearly demonstrated by observations of a G6V-type star of magnitude 8. This star is similar to, but slightly less heavy than our Sun and about 5 times fainter than the faintest stars visible with the unaided eye. During an exposure lasting only one minute, a signal-to-noise ratio (S/N) of 45 per pixel was achieved - this allows to determine the star's radial velocity with an uncertainty of only ~1 m/s! . For comparison, the velocity of a briskly walking person is about 2 m/s. A main performance goal of the HARPS instrument has therefore been reached, already at this early moment. This result also demonstrates an impressive gain in efficiency of no less than about 75 times as compared to that achievable with its predecessor CORALIE. That instrument has been operating very successfully at the 1.2-m Swiss Leonard Euler telescope at La Silla and has discovered several exoplanets during the past years, see for instance ESO Press Releases ( PR 18/98 , PR 13/00 and PR 07/01 ). In practice, this means that this new planet searcher at La Silla can now investigate many more stars in a given observing time and consequently with much increased probability for success. Extraordinary stability ESO PR Photo 08e/03 ESO PR Photo 08e/03 [Preview - JPEG: 478 x 400 pix - 38k [Normal - JPEG: 955 x 800 pix - 111k] Captions : PR Photo 08e/03 is a powerful demonstration of the extraordinary stability of the HARPS spectrograph. It plots the instrumentally induced velocity change, as measured during one night (9 consecutive hours) in the commissioning period. The drift of the instrument is determined by computing the exact position of the Thorium emission lines. As can be seen, the drift is of the order of 1 m/s during 9 hours and is measured with an accuracy of only 20 cm/s. The goal of measuring velocities of stars with an accuracy comparable to that of a pedestrian has required extraordinary efforts for the design and construction of this instrument. Indeed, HARPS is the most stable spectrograph ever built for astronomical applications . A crucial measure in this respect is the location of the HARPS spectrograph in a climatized room in the telescope building. The starlight captured by the 3.6-m telescope is guided to the instrument through a very efficient optical fibre from the telescope's Cassegrain focus. Moreover, the spectrograph is placed inside a vacuum tank to reduce to a minimum any movement of the sensitive optical elements because of changes in pressure and temperature. The temperature of the critical components of HARPS itself is kept very stable, with less than 0.005 degree variation and the spectrum therefore drifts by less than 2 m/s per night. This is a very small value - 1 m/s corresponds to a displacement of the stellar spectrum on the CCD detector by about 1/1000 the size of one CCD pixel, which is equivalent to 15 nm or only about 150 silicon atoms! This drift is continuously measured by means of a Thorium spectrum which is simultaneously recorded on the detector with an accuracy of only 20 cm/s. PR Photo 08e/03 illustrates two fundamental issues: HARPS performs with an overall stability never before reached by any other astronomical spectrograph , and it is possible to measure any nightly drift with an accuracy never achieved before [1]. During this first commissioning period in February 2003, all instrument functions were tested, as well as the complete data flow system hard- and software. Already during the second test night, the data-reduction pipeline was used to obtain the extracted and wavelength-calibrated spectra in a completely automatic way. The first spectra obtained with HARPS will now allow the construction of templates needed to compute the radial velocities of different types of stars with the best efficiency. The second commissioning period in June will then be used to achieve the optimal performance of this new, very powerful instrument. Astronomers in the ESO community will have the opportunity to observe with HARPS from October 1, 2003. Other research opportunities opening This superb radial velocity machine will also play an important role for the study of stellar interiors by asteroseismology. Oscillation modes were recently discovered in the nearby solar-type star Alpha Centauri A from precise radial velocity measurements carried out with CORALIE (see ESO PR 15/01 ). HARPS is able to carry out similar measurements on fainter stars, thus reaching a much wider range of masses, spectral characteristics and ages. Michel Mayor , Director of the Geneva Observatory and co-discoverer of the first known exoplanet, is confident: "With HARPS operating so well already during the first test nights, there is every reason to believe that we shall soon see some breakthroughs in this field also" . The HARPS Consortium HARPS has been designed and built by an international consortium of research institutes, led by the Observatoire de Genève (Switzerland) and including Observatoire de Haute-Provence (France), Physikalisches Institut der Universität Bern (Switzerland), the Service d'Aeronomie (CNRS, France), as well as ESO La Silla and ESO Garching . The HARPS consortium has been granted 100 observing nights per year during a 5-year period at the ESO 3.6-m telescope to perform what promises to be the most ambitious systematic search for exoplanets so far implemented worldwide . The project team is directed by Michel Mayor (Principal Investigator), Didier Queloz (Mission Scientist), Francesco Pepe (Project Managers Consortium) and Gero Rupprecht (ESO representative).

Checking collagen preservation in archaeological bone by non-destructive studies (Micro-CT and IBA)

NASA Astrophysics Data System (ADS)

Beck, L.; Cuif, J.-P.; Pichon, L.; Vaubaillon, S.; Dambricourt Malassé, A.; Abel, R. L.

2012-02-01

The material to be studied is a piece of human skull discovered (1999) in Pleistocene sediments from the Orsang river (Gujarat state, India). From anatomical view point, this skull is highly composite: modern Homo sapiens characters are associated to undoubtedly more ancient features. Absolute dating by 14C is critical to understand this discovery. Prior to dating measurements, non-destructive studies have been carried out. Micro-CT reconstruction (X-ray microtomography) and Ion Beam Analysis (IBA) have been undertaken to check the structural preservation of the fossil and the collagen preservation. PIXE elemental map was used to select well-preserved bone area. RBS/EBS and NRA were used for light element quantification, in particular C, N and O contents. We also demonstrate that the PIXE-RBS/EBS combination is a effective tool for the whole characterization of archaeological and recent bones by analysing in one experiment both mineral and organic fractions. We have shown that the archaeological bone, a fragment of the potentially oldest modern Indian, is enough preserved for radiocarbon dating. We propose that Elastic Backscattering Spectrometry (EBS) using 3 MeV protons could be a good non destructive alternative to conventional CHN method using Carbon-Hydrogen-Nitrogen analyzer for measuring C and N before 14C dating.

Evaluation and mapping of PM2.5 atmospheric aerosols in Arasia region using PIXE and gravimetric measurements

NASA Astrophysics Data System (ADS)

Roumie, M.; Chiari, M.; Srour, A.; Sa'adeh, H.; Reslan, A.; Sultan, M.; Ahmad, M.; Calzolai, G.; Nava, S.; Zubaidi, Th.; Rihawy, M. S.; Hussein, T.; Arafah, D.-E.; Karydas, A. G.; Simon, A.; Nsouli, B.

2016-03-01

The present work is a part of a scientific study conducted among several Arab countries in west Asia, under an International Atomic Energy Agency (IAEA) regional technical cooperation project for Arasia region. The project aims at producing for the first time a database of particulate matter (PM) elemental concentrations in the region that will help in future air quality studies in order to identify commonalities and differences in the presence and contribution of fingerprint pollution sources among the Arasia Member States. The first regional campaign was launched simultaneously in Lebanon, Iraq, Jordan, Syria and United Arab Emirates, using a harmonized sampling and analysis protocol of PM10 and PM2.5 samples. Different samples, collected between October 2014 and February 2015, from the participating countries, were analyzed by PIXE technique and gravimetric measurements were also carried out. The first results of the study will be discussed in a regional perspective. Our study shows that concentrations of fine aerosol fractions are often exceeding the WHO standard values as well as showing some disparities in the obtained values between the different sampling sites. However, some trend similarities of variations with time could also be observed, suggesting a common influence by trans-boundary or external sources of air pollution.

PIXE Analysis of Metal Hull Bolts From HMB DeBraak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Correll, Francis D.; Cole, Lord K.; Slater, Charles J.

2009-03-10

HMB DeBraak was a 16-gun British brig-sloop that sank in a squall on May 25, 1798 off Cape Henlopen, Delaware. Silt covered the wooden hull shortly after it sank, preserving it until DeBraak was raised in 1986. The items recovered from the ship include metal bolts that held the hull together. We used PIXE to measure the compositions of 45 of the bolts and found that they are nearly pure copper (98.3% on average), with most also containing small amounts of iron (0.87%), nickel (0.039%), arsenic (0.43%), silver (0.089%), lead (0.18%), and bismuth (0.12%). A few contain a little indium,more » tin, or antimony, but none contain zinc above the quantization level. The compositions are similar to those reported for 18th-century English copper, but different from several copper alloys also used to make hull bolts. We conclude that, when DeBraak was last fitted out in 1795-1797, the Royal Navy was still using bolts similar to William Forbes's mechanically hardened pure copper bolts. Forbes's process represents the successful innovation and application of new technology in Royal Navy ships during the wars of the late 18th century.« less

In-pixel conversion with a 10 bit SAR ADC for next generation X-ray FELs

NASA Astrophysics Data System (ADS)

Lodola, L.; Batignani, G.; Benkechkache, M. A.; Bettarini, S.; Casarosa, G.; Comotti, D.; Dalla Betta, G. F.; Fabris, L.; Forti, F.; Grassi, M.; Latreche, S.; Malcovati, P.; Manghisoni, M.; Mendicino, R.; Morsani, F.; Paladino, A.; Pancheri, L.; Paoloni, E.; Ratti, L.; Re, V.; Rizzo, G.; Traversi, G.; Vacchi, C.; Verzellesi, G.; Xu, H.

2016-07-01

This work presents the design of an interleaved Successive Approximation Register (SAR) ADC, part of the readout channel for the PixFEL detector. The PixFEL project aims at substantially advancing the state-of-the-art in the field of 2D X-ray imaging for applications at the next generation Free Electron Laser (FEL) facilities. For this purpose, the collaboration is developing the fundamental microelectronic building blocks for the readout channel. This work focuses on the design of the ADC carried out in a 65 nm CMOS technology. To obtain a good tradeoff between power consumption, conversion speed and area occupation, an interleaved SAR ADC architecture was adopted.

VizieR Online Data Catalog: New companions to nearby low-mass stars (Jodar+, 2013)

NASA Astrophysics Data System (ADS)

Jodar, E.; Perez-Garrido, A.; Diaz-Sanchez, A.; Villo, I.; Rebolo, R.; Perez-Prieto, J. A.

2016-04-01

we present the results of a high-resolution imaging survey of 451 late K and M dwarfs selected from the Gliese catalogue (Gliese 1969; Gliese & Jahreiss 1979, 1991, Cat. V/70). The observations were carried out during 2008 using Astralux at the 2.2m telescope at the Centro Astronomico Hispano Aleman (CAHA, Almeria, Spain) and FastCam at the 1.5m Carlos Sanchez Telescope at Teide Observatory (OT, Tenerife, Spain). The observations were done in the Sloan Digital Sky Survey (SDSS) i band at CAHA with pixel scales of ~47mas/pix and the Johnson-Cousin I band at OT with ~43mas/pix. (3 data files).

Analysis of Lung Tissue Using Ion Beams

NASA Astrophysics Data System (ADS)

Alvarez, J. L.; Barrera, R.; Miranda, J.

2002-08-01

In this work a comparative study is presented of the contents of metals in lung tissue from healthy patients and with lung cancer, by means of two analytical techniques: Particle Induced X-ray Emission (PIXE) and Rutherford Backscattering Spectrometry (RBS). The samples of cancerous tissue were taken from 26 autopsies made to individuals died in the National Institute of Respiratory Disease (INER), 22 of cancer and 4 of other non-cancer biopsies. When analyzing the entirety of the samples, in the cancerous tissues, there were increments in the concentrations of S (4%), K (635%), Co (85%) and Cu (13%). Likewise, there were deficiencies in the concentrations of Cl (59%), Ca (6%), Fe (26%) and Zn (7%). Only in the cancerous tissues there were appearances of P, Ca, Ti, V, Cr, Mn, Ni, Br and Sr. The tissue samples were classified according to cancer types (adenocarcinomas, epidermoides and of small cell carcinoma), personal habits (smokers and alcoholic), genetic predisposition and residence place. There was a remarkable decrease in the concentration of Ca and a marked increment in the Cu in the epidermoide tissue samples with regard to those of adenocarcinoma or of small cells cancer. Also, decrements were detected in K and increments of Fe, Co and Cu in the sample belonging to people that resided in Mexico City with regard to those that resided in the State of Mexico.

Bioacumulation of trace elements in hepatic and renal tissues of the white mullet Mugil curema Valenciennes, 1836 (Actinopterygii, Mugilidae) in two coastal systems in southeastern Brazil

NASA Astrophysics Data System (ADS)

Fernandez, W. S.; Dias, J. F.; Boufleur, L. A.; Amaral, L.; Yoneama, M. L.; Dias, J. F.

2014-01-01

The aim of this study is to investigate the presence and the concentration of trace elements in hepatic and renal tissues of white mullet (Mugil curema) by Particle-induced X-ray emission (PIXE). Fish specimens were collected in two coastal areas of São Paulo state-Brazil: the Santos estuary (from March 2009 to February 2010) and the Cananéia-Iguape coastal estuarine system (from May 2008 to April 2009). For the elemental analysis, n = 470 sample tissues (liver and kidney) were pooled according to location and type of organ. Trace elements such as Fe, Cu, Zn and Br were observed in both tissues of M. curema with concentrations ranging from 800 μg g-1 for Fe to 7 μg g-1 for Cu. The concentrations of Cu and Zn showed statistical significant differences among the tissues of M. curema (p < 0.05). Relatively higher concentrations of Cu and Zn were observed in the liver tissue. There was no significantly difference in the elemental concentrations between the two studied areas. The Cu levels in liver tissues of M. curema were found to be above the maximum limits for consumption, according to the United States Environmental Protection Agency (EPA) and Brazilian National Health Surveillance Agency (ANVISA).

DNA damage induced by coal dust, fly and bottom ash from coal combustion evaluated using the micronucleus test and comet assay in vitro.

PubMed

Matzenbacher, Cristina Araujo; Garcia, Ana Letícia Hilario; Dos Santos, Marcela Silva; Nicolau, Caroline Cardoso; Premoli, Suziane; Corrêa, Dione Silva; de Souza, Claudia Telles; Niekraszewicz, Liana; Dias, Johnny Ferraz; Delgado, Tânia Valéria; Kalkreuth, Wolfgang; Grivicich, Ivana; da Silva, Juliana

2017-02-15

Coal mining and combustion generating huge amounts of bottom and fly ash are major causes of environmental pollution and health hazards due to the release of polycyclic aromatic hydrocarbons (PAH) and heavy metals. The Candiota coalfield in Rio Grande do Sul, is one of the largest open-cast coal mines in Brazil. The aim of this study was to evaluate genotoxic and mutagenic effects of coal, bottom ash and fly ash samples from Candiota with the comet assay (alkaline and modified version) and micronucleus test using the lung fibroblast cell line (V79). Qualitative and quantitative analysis of PAH and inorganic elements was carried out by High Performance Liquid Chromatography (HPLC) and by Particle-Induced X-ray Emission (PIXE) techniques respectively. The samples demonstrated genotoxic and mutagenic effects. The comet assay modified using DNA-glicosilase formamidopirimidina (FPG) endonuclease showed damage related to oxidative stress mechanisms. The amount of PAHs was higher in fly ash followed by pulverized coal. The amount of inorganic elements was highest in fly ash, followed by bottom ash. It is concluded that the samples induce DNA damage by mechanisms that include oxidative stress, due to their complex composition, and that protective measures have to be taken regarding occupational and environmental hazards. Copyright © 2016 Elsevier B.V. All rights reserved.

CFHT and VLT Identify Extremely Remote Galaxy

NASA Astrophysics Data System (ADS)

2003-05-01

Top Telescopes Peer into the Distant Past Summary With improved telescopes and instruments, observations of extremely remote and faint galaxies have become possible that were until recently astronomers' dreams. One such object was found by a team of astronomers [2] with a wide-field camera installed at the Canada-France-Hawaii telescope at Mauna Kea (Hawaii, USA) during a search for extremely distant galaxies. Designated "z6VDF J022803-041618" , it was detected because of its unusual colour , being visible only on images obtained through a special optical filter isolating light in a narrow near-infrared band. A follow-up spectrum of this object with the FORS2 multi-mode instrument at the ESO Very Large Telescope (VLT) confirmed that it is a very distant galaxy (the redshift is 6.17 [3]). It is seen as it was when the Universe was only about 900 million years old . z6VDF J022803-041618 is one of the most distant galaxies for which spectra have been obtained so far. Interestingly, it was discovered because of the light emitted by its massive stars and not, as originally expected, from emission by hydrogen gas. PR Photo 13a/03 : Emission from the Earth's atmosphere. PR Photo 13b/03 : CHFT images of the very remote galaxy z6VDF J022803-041618. PR Photo 13c/03 : VLT spectrum of very remote galaxy z6VDF J022803-041618. PR Photo 13d/03 : Cleaned tracing of the VLT spectrum. A brief history of the early Universe Most scientists agree that the Universe emanated from a hot and extremely dense initial state in a Big Bang . The latest observations indicate that this crucial event took place about 13,700 million years ago . During the first few minutes, enormous quantities of hydrogen and helium nuclei with protons and neutrons were produced. There were also lots of free electrons and during the following epoch, the numerous photons were scattered from these and the atomic nuclei. At this stage, the Universe was completely opaque. After some 100,000 years, the Universe had cooled down to a few thousand degrees and the nuclei and electrons now combined to form atoms. The photons were then no longer scattered from these and the Universe suddenly became transparent . Cosmologists refer to this moment as the "recombination epoch" . The microwave background radiation we now observe from all directions depicts the state of great uniformity in the Universe at that distant epoch. In the next phase, the primeval atoms - more than 99% of which were of hydrogen and helium - moved together and began to form huge clouds from which stars and galaxies later emerged . The first generation of stars and, somewhat later, the first galaxies and quasars [4], produced intensive ultraviolet radiation. That radiation did not travel very far, however, despite the fact that the Universe had become transparent a long time ago. This is because the ultraviolet (short-wavelength) photons would be immediately absorbed by the hydrogen atoms, "knocking" electrons off those atoms, while longer-wavelength photons could travel much farther. The intergalactic gas thus again became ionized in steadily growing spheres around the ionizing sources. At some moment, these spheres had become so big that they overlapped completely; this is referred to as the "epoch of re-ionization" . Until then, the ultraviolet radiation was absorbed by the atoms, but the Universe now also became transparent to this radiation. Before, the ultraviolet light from those first stars and galaxies could not be seen over large distances, but now the Universe suddenly appeared to be full of bright objects. It is for this reason that the time interval between the epochs of "recombination" and "re-ionization" is referred to as the "Dark Ages" . When was the end of the "Dark Ages"? The exact epoch of re-ionization is a subject of active debate among astronomers, but recent results from ground and space observations indicate that the "Dark Ages" lasted a few hundred million years . Various research programmes are now underway which attempt to determine better when these early events happened. For this, it is necesary to find and study in detail the earliest and hence, most distant, objects in the Universe - and this is a very demanding observational endeavour. Light is dimmed by the square of the distance and the further we look out in space to observe an object - and therefore the further back in time we see it - the fainter it appears. At the same time, its dim light is shifted towards the red region of the spectrum due to the expansion of the Universe - the larger the distance, the larger the observed redshift [3]. The Lyman-alpha emission line With ground-based telescopes, the faintest detection limits are achieved by observations in the visible part of the spectrum. The detection of very distant objects therefore requires observations of ultraviolet spectral signatures which have been redshifted into the visible region. Normally, the astronomers use for this the redshifted Lyman-alpha spectral emission line with rest wavelength 121.6 nm; it corresponds to photons emitted by hydrogen atoms when they change from an excited state to their fundamental state. One obvious way of searching for the most distant galaxies is therefore to search for Lyman-alpha emission at the reddest (longest) possible wavelengths . The longer the wavelength of the observed Lyman-alpha line, the larger is the redshift and the distance, and the earlier is the epoch at which we see the galaxy and the closer we come towards the moment that marked the end of the "Dark Ages". CCD-detectors used in astronomical instruments (as well as in commercial digital cameras) are sensitive to light of wavelengths up to about 1000 nm (1 µm), i.e., in the very near-infrared spectral region, beyond the reddest light that can be perceived by the human eye at about 700-750 nm. The bright near-infrared night sky ESO PR Photo 13a/03 ESO PR Photo 13a/03 [Preview - JPEG: 759 x 400 pix - 37k [Normal - JPEG: 1518 x 800 pix - 248k] Caption : PR Photo 13a/03 shows a spectrum of emission by the terrestrial atmosphere. In the spectral region above 700 nm, this emission is dominated by strong lines from the OH molecule. By observing in "windows" of low OH emission, such as those around 820 or 920 nm, the "noise" caused by the OH-emission is strongly reduced and it is possible to detect fainter celestial objects. There is another problem, however, for this kind of work. The search for faint Lyman-alpha emission from distant galaxies is complicated by the fact that the terrestrial atmosphere - through which all ground-based telescopes must look - also emits light . This is particularly so in the red and near-infrared part of the spectrum where hundreds of discrete emission lines originate from the hydroxyl molecule (the OH radical) that is present in the upper terrestrial atmosphere at an altitude of about 80 km (see PR Photo 13a/03 ). This strong emission which the astronomers refer to as the "sky background" is responsible for the faintness limit at which celestial objects can be detected with ground-based telescopes at near-infrared wavelengths. However, there are fortunately spectral intervals of "low OH-background" where these emission lines are much fainter, thus allowing a fainter detection limit from ground observations. Two such "dark-sky windows" are evident in PR Photo 13a/03 near wavelengths of 820 and 920 nm. Considering these aspects, a promising way to search efficiently for the most distant galaxies is therefore to observe at wavelengths near 920 nm by means of a narrow-band optical filter. Adapting the spectral width of this filter to about 10 nm allows the detection of as much light from the celestial objects as possible when emitted in a spectral line matching the filter, while minimizing the adverse influence of the sky emission. In other words, with a maximum of light collected from the distant objects and a minimum of disturbing light from the terrestrial atmosphere, the chances for detecting those distant objects are optimal. The astronomers talk about "maximizing the contrast" of objects showing emission lines at this wavelength. The CFHT Search Programme ESO PR Photo 13b/03 ESO PR Photo 13b/03 [Preview - JPEG: 494 x 400 pix - 83k [Normal - JPEG: 987 x 800 pix - 920k] Caption : PR Photo 13b/03 displays the image of a particular object (at the center), as seen at various wavelengths (colours) on CCD-frames obtained through different optical filters with the CFH12K camera at the CFHT. The object is only visible in the NB920 frame in which emission at the near-infrared wavelength 920 nm is registered (upper left). It is not seen in any of the others ( B lue [450 nm], V isual [550 nm], R ed [650 nm], I [800 nm]), nor in a combination of these (the "sum" of BVRI , the so-called "detection" image, here labeled as "Det"; it is used to detect closer objects from their optical colours for spectroscopic follow-up observations). The indicated object was later shown to be an extremely distant galaxy and has been designated z6VDF J022803-041618 . Each of the six photos covers 20 x 20 arcsec 2 ; North is up, East is right. Based on the above considerations, an international team of astronomers [2] installed a narrow-band optical filter centered at the near-infrared wavelength 920 nm on the CFH12K instrument at the Canada-France-Hawaii telescope on Mauna Kea (Hawaii, USA) to search for extremely distant galaxies. The CFH12K is a wide-field camera used at the prime focus of the CFHT, providing a field-of-view of approx. 30 x 40 arcmin 2 , somewhat larger than the full moon [5]. By comparing images of the same sky field taken through different filters, the astronomers were able to identify objects which appear comparatively "bright" in the NB920 image and "faint" (or are even not visible) in the corresponding images obtained through the other filters. A striking example is shown in PR Photo 13b/03 - the object at the center is well visible in the 920nm image, but not at all in the other images. The most probable explanation for an object with such an unusual colour is that it is a very distant galaxy for which the observed wavelength of the strong Lyman-alpha emission line is close to 920 nm, due to the redshift. Any light emitted by the galaxy at wavelengths shorter than Lyman-alpha is strongly absorbed by intervening interstellar and intergalactic hydrogen gas; this is the reason that the object is not visible in all the other filters. The VLT spectrum ESO PR Photo 13c/03 ESO PR Photo 13c/03 [Preview - JPEG: 756 x 300 pix - 68k [Normal - JPEG: 1512 x 600 pix - 552k] ESO PR Photo 13d/03 ESO PR Photo 13d/03 [Preview - JPEG: 479 x 400 pix - 41k [Normal - JPEG: 957 x 800 pix - 272k] Captions : PR Photo 13c/03 shows a spectroscopic image (between the horizontal arrows) of the very distant galaxy z6VDF J022803-041618 at the center of PR Photo 13b/03 , obtained with the multi-mode FORS2 instrument at the 8.2-m VLT YEPUN telescope at the ESO Paranal Observatory. The horizontal axis shows the dispersed light, with wavelengths increasing from left to right. In this spectral image, the bright emission lines from OH molecules in the terrestrial atmosphere, cf. PR Photo 13a/03 , have been subtracted, but they still leave residual "imprints", visible as strong and "noisy" vertical bars. The "window" at wavelength 920 nm is clearly visible on the right side of the image; in this region, there is much less "noise" from the OH-lines. The dark spot at the bottom left of the image is the Lyman-alpha line of the object. The adjacent "continuum" emission from the object, although very faint, is clearly visible on the long-wavelength side (to the right) of the Lyman-alpha line. There is no such continuum emission detected on the short-wavelength side (to the left) of the Lyman alpha line. Together with the observed asymmetry of the line, this is a clear spectral fingerprint of the redshifted Lyman-alpha emission line from a distant galaxy. PR Photo 13d/03 shows a tracing of the spectrum of this galaxy, as extracted from the image in PR Photo 13c/03 . The strong emission line at wavelength 872 nm is the redshifted Lyman-alpha spectral line from the galaxy; it is shown in more detail in the insert panel. In order to learn the true nature of this object, it is necessary to perform a spectroscopic follow-up, by observing its spectrum. This was accomplished with the FORS 2 multi-mode instrument at the 8.2-m VLT YEPUN telescope at the ESO Paranal Observatory. This facility provides a perfect combination of moderate spectral resolution and high sensitivity in the red for this kind of very demanding observation. The resulting (faint) spectrum is shown in PR Photo 13c/03 . PR Photo 13d/03 shows a tracing of the final ("cleaned") spectrum of the object after extraction from the image shown in PR Photo 13c/03 . One broad emission line is clearly detected (to the left of the center; enlarged in the insert). It is asymmetric, being depressed on its blue (left) side. This, combined with the fact that no continuum light is detected to the left of the line, is a clear spectral signature of the Lyman-alpha line: photons "bluer" than Lyman-alpha are heavily absorbed by the gas present in the galaxy itself, and in the intergalactic medium along the line-of-sight between the Earth and the object. The spectroscopic observations therefore allowed the astronomers to identify unambiguously this line as Lyman-alpha, and therefore to confirm the great distance (high redshift) of this particular object. The measured redshift is 6.17, making this object one of the most distant galaxies ever detected . It received the designation "z6VDF J022803-041618" - the first part of this somewhat unwieldy name refers to the survey and the second indicates the position of this galaxy in the sky. Starlight in the early Universe However, these observations did not come without surprise! The astronomers had hoped (and expected) to detect the Lyman-alpha line from the object at the center of the 920 nm spectral window. However, while the Lyman-alpha line was found, it was positioned at a somewhat shorter wavelength. Thus, it was not the Lyman-alpha emission that caused this galaxy to be "bright" in the narrow-band (NB920) image, but "continuum" emission at wavelengths longer than that of Lyman-alpha . This radiation is very faintly visible as a horizontal, diffuse line in PR Photo 13c/03 . One consequence is that the measured redshift of 6.17 is lower than the originally predicted redshift of about 6.5. Another is that z6VDF J022803-041618 was detected by light from its massive stars (the "continuum") and not by emission from hydrogen gas (the Lyman-alpha line). This interesting conclusion is of particular interest as it shows that it is in principle possible to detect galaxies at this enormous distance without having to rely on the Lyman-alpha emission line, which may not always be present in the spectra of the distant galaxies. This will provide the astronomers with a more complete picture of the galaxy population in the early Universe. Moreover, observing more and more of these distant galaxies will help to better understand the ionization state of the Universe at this age: the ultraviolet light emitted by these galaxies should not reach us in a "neutral" Universe, i.e., before re-ionization occurred. The hunt for more such galaxies is now on to clarify how the transition from the Dark Ages happened!

Analysis of biological materials using a nuclear microprobe

NASA Astrophysics Data System (ADS)

Mulware, Stephen Juma

The use of nuclear microprobe techniques including: Particle induced x-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) for elemental analysis and quantitative elemental imaging of biological samples is especially useful in biological and biomedical research because of its high sensitivity for physiologically important trace elements or toxic heavy metals. The nuclear microprobe of the Ion Beam Modification and Analysis Laboratory (IBMAL) has been used to study the enhancement in metal uptake of two different plants. The roots of corn (Zea mays) have been analyzed to study the enhancement of iron uptake by adding Fe (II) or Fe(III) of different concentrations to the germinating medium of the seeds. The Fe uptake enhancement effect produced by lacing the germinating medium with carbon nanotubes has also been investigated. The aim of this investigation is to ensure not only high crop yield but also Fe-rich food products especially from calcareous soil which covers 30% of world's agricultural land. The result will help reduce iron deficiency anemia, which has been identified as the leading nutritional disorder especially in developing countries by the World Health Organization. For the second plant, Mexican marigold (Tagetes erecta ), the effect of an arbuscular mycorrhizal fungi (Glomus intraradices ) for the improvement of lead phytoremediation of lead contaminated soil has been investigated. Phytoremediation provides an environmentally safe technique of removing toxic heavy metals (like lead), which can find their way into human food, from lands contaminated by human activities like mining or by natural disasters like earthquakes. The roots of Mexican marigold have been analyzed to study the role of arbuscular mycorrhizal fungi in enhancement of lead uptake from the contaminated rhizosphere.

Complementary microanalysis of Zn, Mn and Fe in the chelicera of spiders and scorpions using scanning MeV-ion and electron microprobes

NASA Astrophysics Data System (ADS)

Schofield, Robert; Lefevre, Harlan; Shaffer, Michael

1989-04-01

Energy-loss scanning transmission ion microscopy (ELSTIM or just STIM), PIXE and electron microprobe techniques are used to investigate certain minor element accumulations in a few spiders and scorpions. STIM and PIXE are used to survey the unsectioned specimens, while electron microprobe techniques are used for higher resolution investigations of several sections of the specimens. Concentration values measured using STIM and PIXE are found to be in satisfactory agreement with those measured using electron probe microanalysis. A garden spider Araneus diadematus is found to contain high concentrations of zinc in a thin layer near the surface of its fangs (reaching 23% of dry weight), and manganese in its marginal teeth (about 5% of dry weight). A wolf spider Alopecosa kochi is found to have similar concentrations of zinc in a layer near the surface of it's fang, and concentrations of manganese reaching 1.5% in a layer beneath the zinc containing layer. A scorpion Centruroides sp. is found to contain high concentrations of iron (reaching 8%) and zinc (reaching 24%) in the tips of teeth on the cheliceral fingers, and manganese (about 5%) in the stinger. The hypothesis that these elements simply harden the cuticle does not appear to explain their segregation patterns.

PFM2: a 32 × 32 processor for X-ray diffraction imaging at FELs

NASA Astrophysics Data System (ADS)

Manghisoni, M.; Fabris, L.; Re, V.; Traversi, G.; Ratti, L.; Grassi, M.; Lodola, L.; Malcovati, P.; Vacchi, C.; Pancheri, L.; Benkechcache, M. E. A.; Dalla Betta, G.-F.; Xu, H.; Verzellesi, G.; Ronchin, S.; Boscardin, M.; Batignani, G.; Bettarini, S.; Casarosa, G.; Forti, F.; Giorgi, M.; Paladino, A.; Paoloni, E.; Rizzo, G.; Morsani, F.

2016-11-01

This work is concerned with the design of a readout chip for application to experiments at the next generation X-ray Free Electron Lasers (FEL). The ASIC, named PixFEL Matrix (PFM2), has been designed in a 65 nm CMOS technology and consists of 32 × 32 pixels. Each cell covers an area of 110 × 110 μm2 and includes a low-noise charge sensitive amplifier (CSA) with dynamic signal compression, a time-variant shaper used to process the preamplifier output signal, a 10-bit successive approximation register (SAR) analog-to-digital converter (ADC) and digital circuitry for channel control and data readout. Two different solutions for the readout channel, based on different versions of the time-variant filter, have been integrated in the chip. Both solutions can be operated in such a way to cope with the high frame rate (exceeding 1 MHz) foreseen for future X-ray FEL machines. The ASIC will be bump bonded to a slim/active edge pixel sensor to form the first demonstrator for the PixFEL X-ray imager. This work has been carried out in the frame of the PixFEL project funded by Istituto Nazionale di Fisica Nucleare (INFN), Italy.

A Supermassive Black Hole in a Nearby Galaxy

NASA Astrophysics Data System (ADS)

2001-03-01

ISAAC Inspects the Center of Centaurus A Summary The nearby galaxy Centaurus A harbours a supermassive black hole at its centre . Using the ISAAC instrument at the ESO Very Large Telescope (VLT) , an international team of astronomers [1] has peered right through the spectacular dust lane of the peculiar galaxy Centaurus A , located approximately 11 million light-years away. They were able to probe the thin disk of gas that surrounds the very center of this galaxy. The new measurements show that the compact nucleus in the middle weighs more than 200 million solar masses ! This is too much just to be due to normal stars. The astronomers thus conclude the existence of a supermassive black hole lurking at the centre of Centaurus A . PR Photo 08a/01 : Visual image of the centre of Centaurus A . PR Photo 08b/01 : ISAAC spectrum of the centre of Centaurus A . PR Photo 08c/01 : The corresponding rotation curve from which the mass of the black hole was deduced. A well studied galaxy with a hidden center ESO PR Photo 08a/01 ESO PR Photo 08a/01 [Preview - JPEG: 352 x 400 pix - 160k] [Normal - JPEG: 704 x 800 pix - 376k] Caption : PR Photo 08a/01 shows a small area in the direction of the heavily obscured centre of the peculiar radio galaxy Centaurus A , as seen in visual light. It measures about 80 x 80 arcsec 2 , or 4400 x 4400 light-year 2 at the distance of this galaxy, and has been reproduced from exposures made with the FORS2 multi-mode instrument at the 8.2-m VLT KUEYEN telescope at Paranal. The full field may be seen in PR Photo 05b/00. Technical information about this photo is available below. The galaxy Centaurus A (NGC 5128) is one of the most studied objects in the southern sky. The unique appearance of this galaxy was already noticed by the famous British astronomer John Herschel in 1847 who catalogued the southern skies and made a comprehensive list of "nebulae". A fine photo of Centaurus A from the VLT was published last year as PR Photo 05b/00. Herschel could not know, however, that this beautiful and spectacular appearance is due to an opaque dust lane that covers the central part of the galaxy. This dust is likely the remain of a cosmic merger between a giant elliptical galaxy, and a smaller spiral galaxy full of dust. Centaurus A is even more spectacular when observed with radio telescopes. It is in fact one of the brightest radio sources in the sky (its name indicates that it is the strongest radio source in the southern constellation Centaurus). At a distance of merely 11 million light-years, it is also the nearest radio galaxy. The radio emission from the very compact centre exhibits strong activity. It has for some time been suspected that this powerful energy release is due to accretion of material onto a massive black hole. The details of the centre have remained largely unknown, due to the dense dust lane that completely obscures the central part of the galaxy in optical light, cf. PR Photo 08a/01 . Observations of the dust emission in the mid-infrared spectral region were carried out with the ISOCAM camera onboard the ESA Infrared Space Observatory . They revealed a structure extending over 5 arcmin (16,500 light-years or 5 kpc), centred on the compact radio source, and very similar to that of a small barred galaxy. This bar may serve to funnel gas towards the active nucleus of the galaxy. Peering through the dust To look into the very centre of the galaxy, the observations must be carried out at wavelengths longer than those of visual light, e.g., in the infrared spectral region. This is because the dust absorbs much less the infrared radiation. Infrared observations of the innermost regions (of Centaurus A (on an arcsec scale) were recently done by a team of astronomers from Italy, UK and USA [1], by means of the multi-mode ISAAC instrument on the ESO Very Large Telescope (VLT) at Paranal Observatory. In fact, the team started their infrared studies of this galaxy already in 1997, using the NICMOS camera on board the Hubble Space Telescope (HST) . That close view of the galaxy nucleus revealed a thin gaseous disk of material close to the center, which looked very much like an accretion disk that was feeding material into a central black hole. The HST image prompted further spectroscopic observations to probe the rotation of the disk, and thus to measure the mass of the central object. The ISAAC spectra ESO PR Photo 08b/01 ESO PR Photo 08b/01 [Preview - JPEG: 400 x 303 pix - 216k] [Normal - JPEG: 800 x 606 pix - 572k] [Hires - JPEG: 2274 x 3000 pix - 4.0M] Caption : PR Photo 08b/01 shows two wavelength regions of one of the infrared ISAAC spectra of the center of Centaurus A . The direction of the long spectrograph slit is vertical and the dispersion (wavelength) direction is horizontal; longer wavelengths are towards the right. The two emission lines shown originate in singly ionized Iron ([FeII]; rest wavelength 1256.68 nm) and in Hydrogen (Paschen-Beta; 1281.81 nm) and both are clearly tilted. This is due to the rapid rotation of the accretion disk surrounding the supermassive black hole in the center of the galaxy. The light from the receding edge of the disk is Doppler-shifted towards the red (to the right) and the light from the part of the disk approaching us is shifted to the left. This may be better seen in the inserted enlargements. Therefore the inclined disk shows a tilted spectrum. These motions may be represented in a rotation curve, cf. PR Photo 08c/01 . There are other emitting areas above and below the nucleus, especially in the Paschen-Beta line. Technical information about these photos is available below. ESO PR Photo 08c/01 ESO PR Photo 08c/01 [Preview - JPEG: 341 x 400 pix - 56k] [Normal - JPEG: 682 x 800 pix - 132k] Caption : PR Photo 08c/01 shows the rotation curve (velocity vrs. distance from the centre) of the disk surrounding the black hole at the centre of Centaurus A . From the ISAAC spectrum displayed in PR Photo 08b/01 , the `average' gas velocities along the slit direction can be derived. Position `0' on the horizontal axis indicates the exact position of the galaxy nucleus; at the distance of Centaurus A , 1 arcsec corresponds to 55.5 light-years (17 pc). The blue triangles and the red squares correspond to emission lines from singly ionized Iron atoms ([Fe II]) and Hydrogen (Paschen-Beta), respectively. The high velocities are the hallmark of a central black hole. The thick solid line represents the expected velocities, assuming the presence of a 200 million solar-mass black hole at the centre. Technical information about these photos is available below. The spectroscopic observations required both a high sensitivity in the infrared and excellent seeing conditions. This combination was achieved using ISAAC at VLT. Peering through the thick walls of dust enshrouding the nuclear region of Centaurus A , the astronomers succeeded in acquiring several high-quality spectra of the thin central disk; the exposure time for each spectrum was (about) 35 min. The spectra did show the characteristic shape of a rotating disk, cf. PR Photo 08b/01 . High-speed motions of the gas in this disk were detected ( PR Photo 08c/01 ), which are the hallmark of a black hole. An analysis of the rotational speed of the disk leads to determination of the total mass of the material inside the disk. This showed that about 200 million solar masses of material resides inside the nuclear disk. A massive black hole The astronomers quickly realized that this enormous mass within the central region cannot be caused by normal stars, as it would then be much more luminous. Instead they conclude that the most conservative explanation for the dark, central mass concentration observed in Centaurus A is indeed a supermassive black hole. The most likely mass of this "central beast" is then about 200 million times the mass of our Sun. This discovery confirms the previous suspicion that the active nucleus of Centaurus A is powered by a supermassive black hole. It is the first time infrared spectroscopy has been used to weigh a black hole. Many other galaxies have dust-enshrouded nuclei, and the excellent capabilities of ISAAC now hold a great potential to discover and weigh many more black holes. More Information The research described in this Press Release is reported in a research article ("Peering through the dust: Evidence for a supermassive Black Hole at the Nucleus of Centaurus A from VLT IR spectroscopy"), that will appear in the international research journal the Astrophysical Journal on March 10, 2001. The full article is also available on the web as astro-ph/0011059. Note [1]: The team is composed by Ethan Schreier (Principal Investigator; Space Telescope Science Institute - STScI, Baltimore, USA), Alessandro Marconi (Arcetri Observatory, Italy), Alessandro Capetti (Turin Observatory, Italy), David Axon (University of Hertfordshire, United Kingdom), Anton Koekemoer (STScI, USA) and Duccio Macchetto (ESA/STScI, USA). Technical information about the photos PR Photo 08a/01 is reproduced from three exposures, obtained during the night of January 31 - February 1, 2000. It is a composite of three exposures in B (300 sec exposure, image quality 0.60 arcsec; here rendered in blue colour), V (240 sec, 0.60 arcsec; green) and R (240 sec, 0.55 arcsec; red). The field covered corresponds to about 80 x 80 arcsec 2 (395 x 395 pix 2 , 1 pix = 0.2 arcsec). North is up and East is left. PR Photo 08b+c/01 : The original ISAAC spectra were exposed for 35 min each with an average seeing of 0.5 arcsec. Three spectrograph slits were used, but only one of these is shown here. It was centered on the nucleus of Centaurus A and oriented at 33°, measured counter-clockwise from the North direction. The spectral pixel size is 0.6 Angstrom x 0.15 arcsec (i.e., 14 km/sec x 8.3 light-year). The large and small figures cover 2300 km/s x 1665 light-years and 1150 km/s x 330 light-years, respectively.

Ion beam analyses of radionuclide migration in heterogeneous rocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alonso, Ursula; Missana, Tiziana; Garcia-Gutierrez, Miguel

2013-07-18

The migration of radionuclides (RN) in the environment is a topic of general interest, for its implications on public health, and it is an issue for the long-term safety studies of deep geological repositories (DGR) for high-level radioactive waste. The role played by colloids on RN migration is also of great concern. Diffusion and sorption are fundamental mechanisms controlling RN migration in rocks and many experimental approaches are applied to determine transport parameters for low sorbing RN in homogeneous rocks. However, it is difficult to obtain relevant data for high sorbing RN or colloids, for which diffusion lengths are extremelymore » short, or within heterogeneous rocks, where transport might be different in different minerals. The ion beam techniques Rutherford Backscattering Spectrometry (RBS) and micro-Particle Induced X-Ray Emission ({mu}PIXE), rarely applied in the field, were selected for their micro-analytical potential to study RN diffusion and surface retention within heterogeneous rocks. Main achievements obtained during last 12 years are highlighted.« less

Theoretical approach to oxygen atom degradation of silver

NASA Technical Reports Server (NTRS)

Fromhold, Albert T., Jr.; Noh, Seung; Beshears, Ronald; Whitaker, Ann F.; Little, Sally A.

1987-01-01

Based on available Rutherford backscattering spectrometry (RBS), proton induced X-ray emission (PIXE) and ellipsometry data obtained on silver specimens subjected to atomic oxygen attack in low Earth orbit STS flight 41-G, a theory was developed to model the oxygen atom degradation of silver. The diffusion of atomic oxygen in a microscopically nonuniform medium is an essential constituent of the theory. The driving force for diffusion is the macroscopic electrochemical potential gradient developed between the specimen surface exposed to the ambient and the bulk of the silver specimen. The longitudinal electric effect developed parallel to the gradient is modified by space charge of the diffusing charged species. Lateral electric fields and concentration differences also exist due to the nonuniform nature of the medium. The lateral concentration differences are found to be more important than the lateral electric fields in modifying the diffusion rate. The model was evaluated numerically. Qualitative agreement exists between the kinetics predicted by the theory and kinetic data taken in ground-based experiments utilizing a plasma asher.

Irrigation water quality in southern Mexico City based on bacterial and heavy metal analyses

NASA Astrophysics Data System (ADS)

Solís, C.; Sandoval, J.; Pérez-Vega, H.; Mazari-Hiriart, M.

2006-08-01

Xochimilco is located in southern Mexico City and represents the reminiscence of the pre-Columbian farming system, the "chinampa" agriculture. "Chinampas" are island plots surrounded by a canal network. At present the area is densely urbanized and populated, with various contaminant sources contributing to the water quality degradation. The canal system is recharged by a combination of treated-untreated wastewater, and precipitation during the rainy season. Over 40 agricultural species, including vegetables, cereals and flowers, are produced in the "chinampas". In order to characterize the quality of Xochimilcos' water used for irrigation, spatial and temporal contaminant indicators such as microorganisms and heavy metals were investigated. Bacterial indicators (fecal coliforms, fecal enterococcus) were analyzed by standard analytical procedures, and heavy metals (such as Fe, Cu, Zn and Pb) were analyzed by particle induced X-ray emission (PIXE). The more contaminated sites coincide with the heavily populated areas. Seasonal variation of contaminants was observed, with the higher bacterial counts and heavy metal concentrations reported during the rainy season.

A method to visualize transdermal nickel permeation in mouse skin using a nickel allergy patch

PubMed Central

Sugiyama, Tomoko; Uo, Motohiro; Wada, Takahiro; Hongo, Toshio; Omagari, Daisuke; Komiyama, Kazuo; Oikawa, Masakazu; Kusama, Mikio; Mori, Yoshiyuki

2015-01-01

Metal patch test is often used in clinical settings when metal-induced contact dermatitis is suspected. However, the transdermal permeation behavior of metal ions from the patch test remains unclear. Current patch tests using high concentrations of metal salt solutions have some side effects, e.g. acute skin reactions to high concentrations of metal salt. To resolve these, estimating metal ion transdermal permeation is wished. In this study, synchrotron radiation X-ray fluorescence (SR-XRF) and micro-focused particle-induced X-ray emission (micro-PIXE) were used to visualize the time-dependent Ni permeation in mouse skin. The cross-sectional diffusion of Ni was visualized in a time-dependent manner. Our results indicate that maximum Ni permeation occurs after 24 h of patch treatment, and the permeated Ni content was high in the epidermis and spread into the dermis beyond the basal layer. This method may be useful to determine the appropriate solution concentration and duration of administration for the patch test. PMID:26484550

Image Accumulation in Pixel Detector Gated by Late External Trigger Signal and its Application in Imaging Activation Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jakubek, J.; Cejnarova, A.; Platkevic, M.

Single quantum counting pixel detectors of Medipix type are starting to be used in various radiographic applications. Compared to standard devices for digital imaging (such as CCDs or CMOS sensors) they present significant advantages: direct conversion of radiation to electric signal, energy sensitivity, noiseless image integration, unlimited dynamic range, absolute linearity. In this article we describe usage of the pixel device TimePix for image accumulation gated by late trigger signal. Demonstration of the technique is given on imaging coincidence instrumental neutron activation analysis (Imaging CINAA). This method allows one to determine concentration and distribution of certain preselected element in anmore » inspected sample.« less

The Review of Nuclear Microscopy Techniques: An Approach for Nondestructive Trace Elemental Analysis and Mapping of Biological Materials.

PubMed

Mulware, Stephen Juma

2015-01-01

The properties of many biological materials often depend on the spatial distribution and concentration of the trace elements present in a matrix. Scientists have over the years tried various techniques including classical physical and chemical analyzing techniques each with relative level of accuracy. However, with the development of spatially sensitive submicron beams, the nuclear microprobe techniques using focused proton beams for the elemental analysis of biological materials have yielded significant success. In this paper, the basic principles of the commonly used microprobe techniques of STIM, RBS, and PIXE for trace elemental analysis are discussed. The details for sample preparation, the detection, and data collection and analysis are discussed. Finally, an application of the techniques to analysis of corn roots for elemental distribution and concentration is presented.

Quantitative analysis of tear film fluorescence and discomfort during tear film instability and thinning.

PubMed

Begley, Carolyn; Simpson, Trefford; Liu, Haixia; Salvo, Eliza; Wu, Ziwei; Bradley, Arthur; Situ, Ping

2013-04-12

The purpose of this study was to test the association between tear film fluorescence changes during tear break-up (TBU) or thinning and the concurrent ocular sensory response. Sixteen subjects kept one eye open as long as possible (MBI), indicated their discomfort level continuously, and rated ocular sensations of irritation, stinging, burning, pricking, and cooling using visual analog scales (VAS). Fluorescence of the tear film was quantified by a pixel-based analysis of the median pixel intensity (PI), TBU, and percentage of dark pixels (DarkPix) over time. A cutoff of 5% TBU was used to divide subjects into either break-up (BU) or minimal break-up (BUmin) groups. Tear film fluorescence decreased (median PI) and the percentage of TBU and DarkPix increased in all trials, with the rate significantly greater in the BU than the BUmin group (Mann-Whitney U test, P < 0.05). The rate of increasing discomfort during trials was highly correlated with the rate of decrease in median PI and developing TBU (Spearman's, r ≥ 0.70). Significant correlations were found between corneal fluorescence, MBI, and sensory measures. Concentration quenching of fluorescein dye with tear film thinning best explains decreasing tear film fluorescence during trials. This was highly correlated with increasing ocular discomfort, suggesting that both tear film thinning and TBU stimulate underlying corneal nerves, although TBU produced more rapid stimulation. Slow increases in tear film hyperosmolarity may cause the gradual increase in discomfort during slow tear film thinning, whereas the sharp increases in discomfort during TBU suggest a more complex stimulus.

The partitioning of Fe, Ni, Cu, Pt, and Au between sulfide, metal, and fluid phases: A pilot study

NASA Astrophysics Data System (ADS)

Ballhaus, C.; Ryan, C. G.; Mernagh, T. P.; Green, D. H.

1994-01-01

This paper describes new experimental and analytical techniques to study element partitioning behavior between crystalline material and a late- to post-magmatic fluid phase. Samples of the fluid phase are isolated at experimental run conditions as synthetic fluid in quartz. Individual fluid inclusions are later analyzed for dissolved metals using Proton Induced X-ray Emission (PIXE). Back reactions between fluid and solid phases during quenching are prevented because the fluid is isolated at the experimental pressure, temperature ( P, T) conditions before quenching occurs. The technique is applied to study the partitioning of chalcophile elements (Fe, Ni, Cu, Pt and Au) between sulfide phases, metal alloys and supercritical SiO 2-NaCl-saturated H2O ± CH4- CO2- H2S fluids. Synthetic Ni-Cu-rich monosulfide solid solution (mss) doped with PtS or Au is packed in a quartz capsule and, together with a hydrogen buffer capsule and compounds to generate a fluid phase, welded shut in an outer Pt or Au metal capsule. The fluid phase is generated by combustion and reaction of various C-H-O fluid components during heating. Depending on capsule material and sample composition, the run products consist of platiniferous or auriferous mss, Pt-Fe, or ( Au, Cu) alloy phases, PtS, Fe 3O 4, sometimes a Cu-rich sulfide melt, and a fluid phase. Samples of the fluid are trapped in the walls of the quartz sample capsule as polyphase fluid inclusions. All phases are now available for analysis: fluid speciation is analyzed by piercing the outer metal capsule under vacuum and feeding the released fluid into a mass spectrometer. Phases and components within fluid inclusions are identified with Raman spectroscopy. Platinum and gold in solid solution in mss are determined with a CAMECA SX50 electron microanalyser. Metal contents trapped in selected fluid inclusions are determined quantitatively by in situ analysis with a proton microprobe using PIXE and a correction procedure specifically developed for quantitative fluid inclusion analysis. Initial results of metal solubilities in the fluid are as follows. Iron decreases from above 6,000 ppm under reduced conditions in the presence of H 2S in the fluid, to less than 1,000 ppm if hematite is stable in the crystalline run product. Copper and gold concentrations in the fluid range from about 600 to over 1200 and from 150 to about 270 ppm, respectively. The solubilities of these two metals in NaCl-saturated fluids are apparently independent of fluid speciations covered here. Nickel is mostly below detection limit (<10 ppm) and apparently poorly soluble in high-temperature fluid phases. Platinum concentrations in fluid inclusions are highly variable even among fluid inclusions of single runs, possibly because Pt tends to form multi-atom complexes in fluid phases.

Hourly elemental concentrations in PM2.5 aerosols sampled simultaneously at urban background and road site during SAPUSS - diurnal variations and PMF receptor modelling

NASA Astrophysics Data System (ADS)

Dall'Osto, M.; Querol, X.; Amato, F.; Karanasiou, A.; Lucarelli, F.; Nava, S.; Calzolai, G.; Chiari, M.

2013-04-01

Hourly-resolved aerosol chemical speciation data can be a highly powerful tool to determine the source origin of atmospheric pollutants in urban environments. Aerosol mass concentrations of seventeen elements (Na, Mg, Al, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr and Pb) were obtained by time (1 h) and size (PM2.5 particulate matter < 2.5 μm) resolved aerosol samples analysed by Particle Induced X-ray Emission (PIXE) measurements. In the Marie Curie European Union framework of SAPUSS (Solving Aerosol Problems by Using Synergistic Strategies), the approach used is the simultaneous sampling at two monitoring sites in Barcelona (Spain) during September-October 2010: an urban background site (UB) and a street canyon traffic road site (RS). Elements related to primary non-exhaust traffic emission (Fe, Cu), dust resuspension (Ca) and anthropogenic Cl were found enhanced at the RS, whereas industrial related trace metals (Zn, Pb, Mn) were found at higher concentrations at the more ventilated UB site. When receptor modelling was performed with positive matrix factorization (PMF), nine different aerosol sources were identified at both sites: three types of regional aerosols (regional sulphate (S) - 27%, biomass burning (K) - 5%, sea salt (Na-Mg) - 17%), three types of dust aerosols (soil dust (Al-Ti) - 17%, urban crustal dust (Ca) - 6%, and primary traffic non-exhaust brake dust (Fe-Cu) - 7%), and three types of industrial aerosol plumes-like events (shipping oil combustion (V-Ni) - 17%, industrial smelters (Zn-Mn) - 3%, and industrial combustion (Pb-Cl) - 5%, percentages presented are average source contributions to the total elemental mass measured). The validity of the PMF solution of the PIXE data is supported by very good correlations with external single particle mass spectrometry measurements. Some important conclusions can be drawn about the PM2.5 mass fraction simultaneously measured at the UB and RS sites: (1) the regional aerosol sources impact both monitoring sites at similar concentrations regardless their different ventilation conditions; (2) by contrast, local industrial aerosol plumes associated with shipping oil combustion and smelters activities have a higher impact on the more ventilated UB site; (3) a unique source of Pb-Cl (associated with combustion emissions) is found to be the major (82%) source of fine Cl in the urban agglomerate; (4) the mean diurnal variation of PM2.5 primary traffic non-exhaust brake dust (Fe-Cu) suggests that this source is mainly emitted and not resuspended, whereas PM2.5 urban dust (Ca) is found mainly resuspended by both traffic vortex and sea breeze; (5) urban dust (Ca) is found the aerosol source most affected by land wetness, reduced by a factor of eight during rainy days and suggesting that wet roads may be a solution for reducing urban dust concentrations.

PixEye Virtual Reality Training has the Potential of Enhancing Proficiency of Laser Trabeculoplasty Performed by Medical Students: A Pilot Study.

PubMed

Alwadani, Fahad; Morsi, Mohammed Saad

2012-01-01

To compare the surgical proficiency of medical students who underwent traditional training or virtual reality training for argon laser trabeculoplasty with the PixEye simulator. The cohort comprised of 47 fifth year male medical students from the College of Medicine, King Faisal University, Saudi Arabia. The cohort was divided into two groups: students (n = 24), who received virtual reality training (VR Group) and students (n = 23), who underwent traditional training (Control Group). After training, the students performed the trabeculoplasty procedure. All trainings were included concurrent power point presentations describing the details of the procedure. Evaluation of surgical performance was based on the following variables: missing the exact location with the laser, overtreatment, undertreatment and inadvertent laser shots to iris and cornea. The target was missed by 8% of the VR Group compared to 55% in the Control Group. Overtreatment and undertreatment was observed in 7% of the VR Group compared to 46% of the Control Group. Inadvertent laser application to the cornea or iris was performed by 4.5% of the VR Group compared to 34% of the Control Group. Virtual reality training on PixEye simulator may enhance the proficiency of medical students and limit possible surgical errors during laser trabeculoplasty. The authors have no financial interest in the material mentioned in this study.

The LHCb VELO upgrade

NASA Astrophysics Data System (ADS)

Dosil Suárez, Álvaro; LHCb VELO Upgrade Group

2016-07-01

The upgrade of the LHCb experiment, planned for 2019, will transform the experiment to a trigger-less system reading out the full detector at 40 MHz event rate. All data reduction algorithms will be executed in a high-level software farm. The upgraded detector will run at luminosities of 2×1033 cm-2 s-1 and probe physics beyond the Standard Model in the heavy flavour sector with unprecedented precision. The Vertex Locator (VELO) is the silicon vertex detector surrounding the interaction region. The current detector will be replaced with a hybrid pixel system equipped with electronics capable of reading out at 40 MHz. The detector comprises silicon pixel sensors with 55×55 μm2 pitch, read out by the VeloPix ASIC, based on the TimePix/MediPix family. The hottest region will have pixel hit rates of 900 Mhits/s yielding a total data rate more than 3 Tbit/s for the upgraded VELO. The detector modules are located in a separate vacuum, separated from the beam vacuum by a thin custom made foil. The detector halves are retracted when the beams are injected and closed at stable beams, positioning the first sensitive pixel at 5.1 mm from the beams. The material budget will be minimised by the use of evaporative CO2 coolant circulating in microchannels within 400 μm thick silicon substrates.

Analysis of dinosaur samples by nuclear microscopy

NASA Astrophysics Data System (ADS)

Wu, Xiankang; Orlić, I.; Tang, S. M.; Wang, Yiming; Wang, Xiaohong; Zhu, Jieqing

1997-07-01

Several dinosaur bone and eggshell fossil samples unearthed at different sites in China were analyzed by means of nuclear microscopy. Concentrations and distributions of elements such as Na, Mg, Al, P, S, Ca, Cr, Mn, Fe, Cu, Zn, As, Br, Sr, Y, Ce, Pb and U, etc. were obtained for each sample. The results of quantitative PIXE and RBS analyses show unusually high concentrations of U and Ce in several samples obtained from a period near the K-T boundary (between Cretaceous and Tertiary periods, 65 million years ago), suggesting that some form of environmental pollution could be the cause of dinosaur extinction.

External micro-PIXE analysis of fluid inclusions: Test of the LABEC facility on samples of quartz veins from Apuan Alps (Italy)

NASA Astrophysics Data System (ADS)

Massi, M.; Calusi, S.; Giuntini, L.; Ruggieri, G.; Dini, A.

2008-05-01

Fluid inclusions are small portions, usually smaller than 100 μm, of fluid trapped within minerals during or after growth. Their characteristics provide therefore fundamental information on nature and evolution of fluids present in the past in different geological environments. At the LABEC laboratory in Firenze, high-salinity fluid inclusions in quartz crystals, coming from the Apuan Alps metamorphic complex, were analysed at the external scanning microbeam. Results, although still preliminary, have already provided us with hints on fluid-rock interaction processes during the metamorphism of the Apuan Alps.

The external scanning proton microprobe of Firenze: A comprehensive description

NASA Astrophysics Data System (ADS)

Giuntini, L.; Massi, M.; Calusi, S.

2007-06-01

An external proton scanning microbeam setup is installed on the -30° line of the new 3 MV tandem accelerator in Firenze; the most relevant features of the line, such as detection setup for IBA measurements, target viewing system, beam diagnostic and transport are described here. With our facility we can work with a beam spot on sample better than 10 μm full-width half-maximum (FWHM) and an intensity of some nanoamperes. Standard beam exit windows are silicon nitride (Si 3N 4) TEM membranes, 100 nm thick and 0.5×0.5 mm 2 wide; we also successfully performed measurements using membranes 1×1 mm 2 wide, 100 nm thick, and 2×2 mm 2 wide, 200 and 500 nm thick. Exploiting the yield of Si X-rays produced by the beam in the exit window as an indirect measurement of the charge, a beam charge monitor system was implemented. The analytical capabilities of the microbeam have been extended by integrating a two-detector PIXE setup with BS and PIGE detectors; the external scanning proton microprobe in Firenze is thus a powerful instrument to fully characterize samples by ion beam analysis, through the simultaneous collection of PIXE, PIGE and BS elemental maps. Its characteristics can make it often competitive with traditional in vacuum microbeam for measurements of thick targets.

Tests of commercial colour CMOS cameras for astronomical applications

NASA Astrophysics Data System (ADS)

Pokhvala, S. M.; Reshetnyk, V. M.; Zhilyaev, B. E.

2013-12-01

We present some results of testing commercial colour CMOS cameras for astronomical applications. Colour CMOS sensors allow to perform photometry in three filters simultaneously that gives a great advantage compared with monochrome CCD detectors. The Bayer BGR colour system realized in colour CMOS sensors is close to the astronomical Johnson BVR system. The basic camera characteristics: read noise (e^{-}/pix), thermal noise (e^{-}/pix/sec) and electronic gain (e^{-}/ADU) for the commercial digital camera Canon 5D MarkIII are presented. We give the same characteristics for the scientific high performance cooled CCD camera system ALTA E47. Comparing results for tests of Canon 5D MarkIII and CCD ALTA E47 show that present-day commercial colour CMOS cameras can seriously compete with the scientific CCD cameras in deep astronomical imaging.

The Zeeman effect in the (0,0) band of the A 7Pi-X 7Sigma(+) transition of manganese monohydride, MnH.

PubMed

Steimle, Timothy C; Wang, Hailing; Gengler, Jamie J; Stoll, Michael; Meijer, Gerard

2008-10-28

The Zeeman tuning of the P(1)(0) line (nu=17 568.35 cm(-1)) of the A (7)Pi-X (7)Sigma(+) (0,0) band of manganese monohydride, MnH, has been investigated. The laser induced fluorescence spectrum of a supersonic molecular beam sample was recorded at a resolution of approximately 40 MHz and with field strengths of up to 362.0 mT. The observed spectrum was successfully fitted using a traditional effective Zeeman Hamiltonian to determine an effective magnetic g-factor for the J=2 level of the F(1)-spin component of the A (7)Pi(v=0) state. Spectral predictions of the P(1)(0) line at field strengths used in magnetic trapping experiments are presented.

ALMA On the Move - ESO Awards Important Contract for the ALMA Project

NASA Astrophysics Data System (ADS)

2005-12-01

Only two weeks after awarding its largest-ever contract for the procurement of antennas for the Atacama Large Millimeter Array project (ALMA), ESO has signed a contract with Scheuerle Fahrzeugfabrik GmbH, a world-leader in the design and production of custom-built heavy-duty transporters, for the provision of two antenna transporting vehicles. These vehicles are of crucial importance for ALMA. ESO PR Photo 41a/05 ESO PR Photo 41a/05 The ALMA Transporter (Artist's Impression) [Preview - JPEG: 400 x 756 pix - 234k] [Normal - JPEG: 800 x 1512 pix - 700k] [Full Res - JPEG: 1768 x 3265 pix - 2.3M] Caption: Each of the ALMA transporters will be 10 m wide, 4.5 m high and 16 m long. "The timely awarding of this contract is most important to ensure that science operations can commence as planned," said ESO Director General Catherine Cesarsky. "This contract thus marks a further step towards the realization of the ALMA project." "These vehicles will operate in a most unusual environment and must live up to very strict demands regarding performance, reliability and safety. Meeting these requirements is a challenge for us, and we are proud to have been selected by ESO for this task," commented Hans-Jörg Habernegg, President of Scheuerle GmbH. ESO PR Photo 41b/05 ESO PR Photo 41b/05 Signing the Contract [Preview - JPEG: 400 x 572 pix - 234k] [Normal - JPEG: 800 x 1143 pix - 700k] [HiRes - JPEG: 4368 x 3056 pix - 2.3M] Caption: (left to right) Mr Thomas Riek, Vice-President of Scheuerle GmbH, Dr Catherine Cesarsky, ESO Director General and Mr Hans-Jörg Habernegg, President of Scheuerle GmbH. When completed on the high-altitude Chajnantor site in Chile, ALMA is expected to comprise more than 60 antennas, which can be placed in different locations on the plateau but which work together as one giant telescope. Changing the relative positions of the antennas and thus also the configuration of the array allows for different observing modes, comparable to using a zoom lens, offering different degrees of resolution and sky coverage as needed by the astronomers. The ALMA Antenna Transporters allow for moving the antennas between the different pre-defined antenna positions. They will also be used for transporting antennas between the maintenance area at 2900 m elevation and the "high site" at 5000 m above sea level, where the observations are carried out. Given their important functions, both for the scientific work and in transporting high-tech antennas with the required care, the vehicles must live up to very demanding operational requirements. Each transporter has a mass of 150 tonnes and is able to lift and transport antennas of 110 tonnes. They must be able to place the antennas on the docking pads with millimetric precision. At the same time, they must be powerful enough to climb 2000 m reliably and safely with their heavy and valuable load, putting extraordinary demands on the 500 kW diesel engines. This means negotiating a 28 km long high-altitude road with an average slope of 7 %. Finally, as they will be operated at an altitude with significantly reduced oxygen levels, a range of redundant safety devices protect both personnel and equipment from possible mishaps or accidents. The first transporter is scheduled to be delivered in the summer of 2007 to match the delivery of the first antennas to Chajnantor. The ESO contract has a value of approx. 5.5 m Euros.

Solution to the inverse problem of estimating gap-junctional and inhibitory conductance in inferior olive neurons from spike trains by network model simulation.

PubMed

Onizuka, Miho; Hoang, Huu; Kawato, Mitsuo; Tokuda, Isao T; Schweighofer, Nicolas; Katori, Yuichi; Aihara, Kazuyuki; Lang, Eric J; Toyama, Keisuke

2013-11-01

The inferior olive (IO) possesses synaptic glomeruli, which contain dendritic spines from neighboring neurons and presynaptic terminals, many of which are inhibitory and GABAergic. Gap junctions between the spines electrically couple neighboring neurons whereas the GABAergic synaptic terminals are thought to act to decrease the effectiveness of this coupling. Thus, the glomeruli are thought to be important for determining the oscillatory and synchronized activity displayed by IO neurons. Indeed, the tendency to display such activity patterns is enhanced or reduced by the local administration of the GABA-A receptor blocker picrotoxin (PIX) or the gap junction blocker carbenoxolone (CBX), respectively. We studied the functional roles of the glomeruli by solving the inverse problem of estimating the inhibitory (gi) and gap-junctional conductance (gc) using an IO network model. This model was built upon a prior IO network model, in which the individual neurons consisted of soma and dendritic compartments, by adding a glomerular compartment comprising electrically coupled spines that received inhibitory synapses. The model was used in the forward mode to simulate spike data under PIX and CBX conditions for comparison with experimental data consisting of multi-electrode recordings of complex spikes from arrays of Purkinje cells (complex spikes are generated in a one-to-one manner by IO spikes and thus can substitute for directly measuring IO spike activity). The spatiotemporal firing dynamics of the experimental and simulation spike data were evaluated as feature vectors, including firing rates, local variation, auto-correlogram, cross-correlogram, and minimal distance, and were contracted onto two-dimensional principal component analysis (PCA) space. gc and gi were determined as the solution to the inverse problem such that the simulation and experimental spike data were closely matched in the PCA space. The goodness of the match was confirmed by an analysis of variance (ANOVA) of the PCA scores between the experimental and simulation spike data. In the PIX condition, gi was found to decrease to approximately half its control value. CBX caused an approximately 30% decrease in gc from control levels. These results support the hypothesis that the glomeruli are control points for determining the spatiotemporal characteristics of olivocerebellar activity and thus may shape its ability to convey signals to the cerebellum that may be used for motor learning or motor control purposes. Copyright © 2013 Elsevier Ltd. All rights reserved.

A Cosmic Baby-Boom

NASA Astrophysics Data System (ADS)

2005-09-01

Large Population of Galaxies Found in the Young Universe with ESO's VLT The Universe was a more fertile place soon after it was formed than has previously been suspected. A team of French and Italian astronomers [1] made indeed the surprising discovery of a large and unknown population of distant galaxies observed when the Universe was only 10 to 30% its present age. ESO PR Photo 29a/05 ESO PR Photo 29a/05 New Population of Distant Galaxies [Preview - JPEG: 400 x 424 pix - 191k] [Normal - JPEG: 800 x 847 pix - 449k] [HiRes - JPEG: 2269 x 2402 pix - 2.0M] ESO PR Photo 29b/05 ESO PR Photo 29b/05 Average Spectra of Distant Galaxies [Preview - JPEG: 400 x 506 pix - 141k] [Normal - JPEG: 800 x 1012 pix - 320k] This breakthrough is based on observations made with the Visible Multi-Object Spectrograph (VIMOS) as part of the VIMOS VLT Deep Survey (VVDS). The VVDS started early 2002 on Melipal, one of the 8.2-m telescopes of ESO's Very Large Telescope Array [2]. In a total sample of about 8,000 galaxies selected only on the basis of their observed brightness in red light, almost 1,000 bright and vigorously star forming galaxies were discovered that were formed between 9 and 12 billion years ago (i.e. about 1,500 to 4,500 million years after the Big Bang). "To our surprise, says Olivier Le Fèvre, from the Laboratoire d'Astrophysique de Marseille (France) and co-leader of the VVDS project, "this is two to six times higher than had been found previously. These galaxies had been missed because previous surveys had selected objects in a much more restrictive manner than we did. And they did so to accommodate the much lower efficiency of the previous generation of instruments." While observations and models have consistently indicated that the Universe had not yet formed many stars in the first billion years of cosmic time, the discovery announced today by scientists calls for a significant change in this picture. The astronomers indeed find that stars formed two to three times faster than previously estimated. "These observations will demand a profound reassessment of our theories of the formation and evolution of galaxies in a changing Universe", says Gianpaolo Vettolani, the other co-leader of the VVDS project, working at INAF-IRA in Bologna (Italy). These results are reported in the September 22 issue of the journal Nature (Le Fèvre et al., "A large population of galaxies 9 to 12 billion years back in the life of the Universe").

Optical Detection of Anomalous Nitrogen in Comets

NASA Astrophysics Data System (ADS)

2003-12-01

VLT Opens New Window towards Our Origins Summary A team of European astronomers [1] has used the UVES spectrograph on the 8.2-m VLT KUEYEN telescope to perform a uniquely detailed study of Comet LINEAR (C/2000 WM1) . This is the first time that this powerful instrument has been employed to obtain high-resolution spectra of a comet. At the time of the observations in mid-March 2002, Comet LINEAR was about 180 million km from the Sun, moving outwards after its perihelion passage in January. As comets are believed to carry "pristine" material - left-overs from the formation of the solar system, about 4,600 million years ago - studies of these objects are important to obtain clues about the origins of the solar system and the Earth in particular. The high quality of the data obtained of this moving 9th-magnitude object has permitted a determination of the cometary abundance of various elements and their isotopes [2]. Of particular interest is the unambiguous detection and measurement of the nitrogen-15 isotope. The only other comet in which this isotope has been observed is famous Comet Hale-Bopp - this was during the passage in 1997, when it was much brighter than Comet LINEAR. Most interestingly, Comet LINEAR and Comet Hale-Bopp display the same isotopic abundance ratio, about 1 nitrogen-15 atom for each 140 nitrogen-14 atoms ( 14 N/ 15 N = 140 ± 30) . That is about half of the terrestrial value (272). It is also very different from the result obtained by means of radio measurements of Comet Hale-Bopp ( 14 N/ 15 N = 330 ± 75). Optical and radio measurements concern different molecules (CN and HCN, respectively), and this isotopic anomaly must be explained by some differentiation mechanism. The astronomers conclude that part of the cometary nitrogen is trapped in macromolecules attached to dust particles . The successful entry of UVES into cometary research now opens eagerly awaited opportunities for similiar observations in other, comparatively faint comets. These studies will provide crucial information about the detailed composition of a much larger number of comets than hitherto possible and hence, more information about the primordial matter from which the solar system formed. A better understanding of the origins of the cometary material (in particular the HCN and CN molecules [3]) and the connection with heavier organic molecules is highly desirable. This is especially so in view of the probable rôle of comets in bringing to the young Earth materials essential for the subsequent formation of life on our planet . PR Photo 28a/03 : Comet LINEAR (C/2000 WM1) - direct image and UVES slit position. PR Photo 28b/03 : Part of the UVES spectrum of Comet LINEAR (C/2000 WM1) with CN-band. PR Photo 28c/03 : Identification of nitrogen-15 in the spectrum. Cometary material Knowledge of the abundance of the stable isotopes [2] of the light elements in different solar system objects provides critical clues to the origin and early evolution of these objects and of the system as a whole. In order to gain the best possible insight into the origins and formation of the niche in which we live, it is therefore important to determine such isotopic abundance ratios in as many members of the solar family as possible. This is particularly true for comets, believed to be carriers of well-preserved specimens of the pristine material from which the solar system was made, some 4,600 million years ago. However, the detailed study of cometary material is a difficult task. Measurements of isotopic ratios is an especially daunting undertaking, mainly because of the extreme weakness of the spectral signatures (emissions) of the less abundant species like carbon-13, nitrogen-15, etc.. Measurements of microwave emission from those atoms suffer from additional, inherent uncertainties connected to the much stronger emission of the more abundant species. Measurements in the optical spectral region thus take on particular importance in this context. However, it is exceedingly difficult to procure the high-quality, high-resolution spectra needed to show the very faint emissions of the rare species. So far, they were only possible when a very bright comet happened to pass by, perhaps once a decade, thereby significantly limiting such studies. And there has always been some doubt whether the brightest comets are also truly representative of this class of objects. Observations of fainter, more typical comets had to await the advent of powerful instruments and telescopes. First UVES spectrum of a comet ESO PR Photo 28a/03 ESO PR Photo 28a/03 [Preview - JPEG: 495 x 400 pix - 183k [Normal - JPEG: 990 x 800 pix - 450k] ESO PR Photo 28b/03 ESO PR Photo 28b/03 [Preview - JPEG: 502 x 400 pix - 115k [Normal - JPEG: 1004 x 800 pix - 290K] Captions : PR Photo 28a/03 displays an image of Comet LINEAR (C/2000 WM1) with the UVES slit viewer image. The colour composite in the large frame (sky field: 16 x 16 arcmin 2 ) was obtained by Gordon Garradd (Loomberah, NSW, Australia). [Image Copyright (c) 2002 Gordon Garradd (loomberah@ozemail.com.au]. The UVES slit viewer photo (small frame; 40 x 40 arcsec 2 ) is a false-colour image taken in the (red) R-band with UVES+KUEYEN on March 22, 2002; it shows the position of the narrow spectrograph slit (0.45 arcsec wide and 8 arcsec long) crossing the inner coma and through which the comet's light was captured to produce the high-resolution spectra. The slit has been offset from the center of light to reduce contamination from solar light reflected off dust particles in the comet's coma - there is most dust near the nucleus. PR Photo 28b/03 shows a small part of the UVES spectrum with an emission band (ultraviolet light at wavelength 390 nm) from CN molecules [3] in the comet's atmosphere. The emission lines are produced by absorption of the solar light by these molecules, followed by re-emission of lines of specific wavelengths. This physical process is known as "resonance-fluorescence" - it is the same process that causes glowing teeth and shirts in a Disco. The upper panel displays the "raw" spectrum; the lower is the "extracted" spectrum, now clearly displaying the individual emission lines. Observations of Comet LINEAR (C/2000 WM1) were carried out with the UV-Visual Echelle Spectrograph (UVES) mounted on the 8.2-m VLT KUEYEN telescope at the ESO Paranal Observatory (Chile) on four occasions during March 2002. At that time, the comet had moved past its perihelion and was by far the faintest comet for which such a detailed spectral analysis had ever been attempted. A number of 25-min exposures were secured, resulting in a total observing time of about 4 hours. The final spectrum covers the entire visual region (330 - 670 nm) and is one of the most detailed and information-rich cometary spectra ever obtained. PR Photo 28b/03 displays a small part of this spectrum. These observations are the first high resolution spectra of a comet taken with the VLT. Identification of nitrogen-15 ESO PR Photo 28c/03 ESO PR Photo 28c/03 [Preview - JPEG: 400 x 524 pix - 109k [Normal - JPEG: 800 x 1047 pix - 285k] Captions : PR Photo 28c/03 is an enlarged view of a small section of the high-resolution UVES spectrum of Comet LINEAR ( PR Photo 28b/03 ) with emission lines from CN-molecules (blue line), compared to the "synthetic" spectrum based on theoretical calculations and laboratory measurements (black line ; some of the lines are labeled with quantum numbers). In the upper panel, the synthetic spectrum has been produced on the basis of the most abundant isotopic species ( 12 C 14 N). The lower panel shows that the observed spectrum is in nearly perfect agreement with a synthetic spectrum which includes contributions from two other isotopic species, 13 C 14 N (emission lines at wavelengths indicated by red ticks) and 12 C 15 N (blue ticks); they are added in proportions of 1/115 and 1/140, respectively. The isotopic abundances of carbon-13 and nitrogen-15 are measured accordingly. Introducing instead the terrestrial ratio for nitrogen-15 (1/272) significantly degrades the fit and thus that ratio can clearly be ruled out in Comet LINEAR. At the time of the VLT observations, the comet was of 9th magnitude, i.e. about 15 times fainter than what can be perceived with the unaided eye. The distance from the Sun was about 180 million km; the distance from the Earth was 186 million km. The observations included calibration spectra of sunlight reflected from the lunar surface; they were used to "subtract" the solar signatures in the comet's spectrum, caused by reflection of sunlight from the dust particles around the comet. As expected, in addition to emission from "normal" CN-molecules ( 12 C 14 N), the UVES data also show emission lines of the 13 C 14 N-molecule that contains the rare isotope carbon-13. The derived 12 C/ 13 C isotopic ratio is 115 ± 20, quite similar to the "standard" solar system value of 89. However, there is also a series of weak features that are positioned exactly at the theoretical wavelengths of emission lines from 12 C 15 N-molecules, cf. PR Photo 28c/03 . The excellent fit that is evident in this diagram proves beyond any doubt the presence of nitrogen-15 in Comet LINEAR and allows a quite accurate determination of the isotopic ratio. The "anomalous" nitrogen isotope ratio in comets In 1997, the same group of astronomers obtained spectra of the (at that time) much brighter Comet Hale-Bopp with the 2.6-m NOT telescope (Roque de los Muchachos Observatory, La Palma, Canary Islands, Spain) in order to investigate the isotopic ratio of carbon-12 to carbon-13. Claude Arpigny remembers: " Interestingly, our spectra of Hale-Bopp showed a number of weak and unidentified emission lines. We later realised that they were positioned close to the theoretical wavelengths of some lines from the 12 C 15 N-molecule. This was a pleasant surprise, as lines from that molecular species were previously believed to be so faint that they would not be observable." He continues: "This identification is now fully confirmed with the UVES observations of Comet LINEAR. Our detections in these two comets are the first ever of those emission lines in comets ". The estimates of the 14 N/ 15 N isotopic ratios are very similar, 140 ± 35 for Hale-Bopp and 140 ± 30 for LINEAR. These ratios are remarkably low and different from the terrestrial value of 272. This means that these comets have comparatively more nitrogen-15 than has the Earth. No measurement has yet been made of the abundance of nitrogen-15 in the Sun. So which of the values corresponds to the composition of the material from which the solar system was made? Different origins? To date, only four cometary values of the 14 N/ 15 N isotopic ratio have been reported: two in the radio wavelength range and the two now measured by means of optical spectra. The radio measurements concern the HCN-molecule (hydrocyanic acid) in Comet Hale-Bopp, a "parent" molecule for the CN-molecules present in comets. Contrary to the optical measurements, the radio values (about 330 ± 75) are compatible with the terrestrial value (272). But radio measurements of carbon and nitrogen isotopic ratios are only possible on extraordinarily bright comets like Hale-Bopp, and even then, the achievable accuracy is very limited. This emphasizes the importance of performing this kind of research by means of optical observations. The origin of the isotopic discrepancy between different CN parents is likely due to fractionation mechanisms in the forming presolar nebula, e.g. when oxygen- and carbon-bearing molecules in high-density nebulae stick to cold (10K) dust grains. Macromolecules in space The astronomers think that the new results indicate that the HCN-molecule cannot be the only "parent" of the CN-molecule; the latter must also be produced by some as yet unknown parent(s) in which the nitrogen-15 isotope is even more abundant. In this connection, it is very interesting that an "excess" of nitrogen-15 is also known to exist in interplanetary dust particles (IDPs), captured by high-flying aircraft in the Earth's atmosphere. They represent the oldest material in the solar system that can be subjected to detailed laboratory analysis. Many of these particles are thought to originate from passing comets - this possibility is obviously supported by the new measurements. The nitrogen-15 carriers in IDPs have not been securely identified but are possibly organic macromolecules or polycyclic aromatic hydrocarbons (PAHs). It is thus possible that the additional parent(s) of cometary CN may belong to this ensemble of organic substances. Whatever the case, the longstanding question of nitrogen and its isotopic ratio(s) in the solar system, whether present and primordial, is notoriously enigmatic in several respects. However, the present results demonstrate that a detailed study of comets may deliver very useful clues. The team has now been granted more observing time with UVES and KUEYEN in order to pursue this important study by observing more comets.

An interlaboratory comparison study on the measurement of elements in PM10

NASA Astrophysics Data System (ADS)

Yatkin, Sinan; Belis, Claudio A.; Gerboles, Michel; Calzolai, Giulia; Lucarelli, Franco; Cavalli, Fabrizia; Trzepla, Krystyna

2016-01-01

An inter-laboratory comparison study was conducted to measure elemental loadings on PM10 samples, collected in Ispra, a regional background/rural site in Italy, using three different XRF (X-ray Fluorescence) methods, namely Epsilon 5 by linear calibration, Quant'X by the standardless analysis, and PIXE (Particle Induced X-ray Emission) with linear calibration. A subset of samples was also analyzed by ICP-MS (Inductively Coupled Plasma-Mass Spectrometry). Several metrics including method detection limits (MDLs), precision, bias from a NIST standard reference material (SRM 2783) quoted values, relative absolute difference, orthogonal regression and the ratio of the absolute difference between the methods to claimed uncertainty were used to compare the laboratories. The MDLs were found to be comparable for many elements. Precision estimates were less than 10% for the majority of the elements. Absolute biases from SRM 2783 remained less than 20% for the majority of certified elements. The regression results of PM10 samples showed that the three XRF laboratories measured very similar mass loadings for S, K, Ti, Mn, Fe, Cu, Br, Sr and Pb with slopes within 20% of unity. The ICP-MS results confirmed the agreement and discrepancies between XRF laboratories for Al, K, Ca, Ti, V, Cu, Sr and Pb. The ICP-MS results are inconsistent with the XRF laboratories for Fe and Zn. The absolute differences between the XRF laboratories generally remained within their claimed uncertainties, showing a pattern generally consistent with the orthogonal regression results.

Elemental maps in human allantochorial placental vessels cells: 1. High K + and acetylcholine effects

NASA Astrophysics Data System (ADS)

Michelet-Habchi, C.; Barberet, Ph.; Dutta, R. K.; Guiet-Bara, A.; Bara, M.; Moretto, Ph.

2003-09-01

Regulation of vascular tone in the fetal extracorporeal circulation most likely depends on circulating hormones, local paracrine mechanisms and changes in membrane potential of vascular smooth muscle cells (VSMCs) and of vascular endothelial cells (VECs). The membrane potential is a function of the physiological activities of ionic channels (particularly, K + and Ca 2+ channels in these cells). These channels regulate the ionic distribution into these cells. Micro-particle induced X-ray emission (PIXE) analysis was applied to determine the ionic composition of VSMC and of VEC in the placental human allantochorial vessels in a physiological survival medium (Hanks' solution) modified by the addition of acetylcholine (ACh: which opens the calcium-sensitive K + channels, K Ca) and of high concentration of K + (which blocks the voltage-sensitive K + channels, K df). In VSMC (media layer), the addition of ACh induced no modification of the Na, K, Cl, P, S, Mg and Ca concentrations and high K + medium increased significantly the Cl and K concentrations, the other ion concentrations remaining constant. In endothelium (VEC), ACh addition implicated a significant increase of Na and K concentration, and high K + medium, a significant increase in Cl and K concentration. These results indicated the importance of K df, K Ca and K ATP channels in the regulation of K + intracellular distribution in VSMC and VEC and the possible intervention of a Na-K-2Cl cotransport and corroborated the previous electrophysiological data.

Beyond Iron: Iridium-Containing P450 Enzymes for Selective Cyclopropanations of Structurally Diverse Alkenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Key, Hanna M.; Dydio, Paweł; Liu, Zhennan

Enzymes catalyze organic transformations with exquisite levels of selectivity, including chemoselectivity, stereoselectivity, and substrate selectivity, but the types of reactions catalyzed by enzymes are more limited than those of chemical catalysts. Thus, the convergence of chemical catalysis and biocatalysis can enable enzymatic systems to catalyze abiological reactions with high selectivity. Recently, we disclosed artificial enzymes constructed from the apo form of heme proteins and iridium porphyrins that catalyze the insertion of carbenes into a C-H bond. Here, we postulated that the same type of Ir(Me)-PIX enzymes could catalyze the cyclopropanation of a broad range of alkenes with control of multiplemore » modes of selectivity. Here, we report the evolution of artificial enzymes that are highly active and highly stereoselective for the addition of carbenes to a wide range of alkenes. These enzymes catalyze the cyclopropanation of terminal and internal, activated and unactivated, electron-rich and electron-deficient, conjugated and nonconjugated alkenes. In particular, Ir(Me)-PIX enzymes derived from CYP119 catalyze highly enantio- and diastereoselective cyclopropanations of styrene with ±98% ee, > 70:1 dr, > 75% yield, and ~10,000 turnovers (TON), as well as 1,2-disubstituted styrenes with up to 99% ee, 35:1 dr, and 54% yield. Moreover, Ir(Me)-PIX enzymes catalyze cyclopropanation of internal, unactivated alkenes with up to 99% stereoselectivity, 76% yield, and 1300 TON. They also catalyze cyclopropanation of natural products with diastereoselectivities that are complementary to those attained with standard transition metal catalysts. Finally, Ir(Me)-PIX P450 variants react with substrate selectivity that is reminiscent of natural enzymes; they react preferentially with less reactive internal alkenes in the presence of more reactive terminal alkenes. Altogether, the studies reveal the suitability of Ir-containing P450s to combine the broad reactivity and substrate scope of transition metal catalysts with the exquisite selectivity of enzymes, generating catalysts that enable reactions to occur with levels and modes of activity and selectivity previously unattainable with natural enzymes or transition metal complexes alone.« less

Beyond Iron: Iridium-Containing P450 Enzymes for Selective Cyclopropanations of Structurally Diverse Alkenes

DOE PAGES

Key, Hanna M.; Dydio, Paweł; Liu, Zhennan; ...

2017-04-01

Enzymes catalyze organic transformations with exquisite levels of selectivity, including chemoselectivity, stereoselectivity, and substrate selectivity, but the types of reactions catalyzed by enzymes are more limited than those of chemical catalysts. Thus, the convergence of chemical catalysis and biocatalysis can enable enzymatic systems to catalyze abiological reactions with high selectivity. Recently, we disclosed artificial enzymes constructed from the apo form of heme proteins and iridium porphyrins that catalyze the insertion of carbenes into a C-H bond. Here, we postulated that the same type of Ir(Me)-PIX enzymes could catalyze the cyclopropanation of a broad range of alkenes with control of multiplemore » modes of selectivity. Here, we report the evolution of artificial enzymes that are highly active and highly stereoselective for the addition of carbenes to a wide range of alkenes. These enzymes catalyze the cyclopropanation of terminal and internal, activated and unactivated, electron-rich and electron-deficient, conjugated and nonconjugated alkenes. In particular, Ir(Me)-PIX enzymes derived from CYP119 catalyze highly enantio- and diastereoselective cyclopropanations of styrene with ±98% ee, > 70:1 dr, > 75% yield, and ~10,000 turnovers (TON), as well as 1,2-disubstituted styrenes with up to 99% ee, 35:1 dr, and 54% yield. Moreover, Ir(Me)-PIX enzymes catalyze cyclopropanation of internal, unactivated alkenes with up to 99% stereoselectivity, 76% yield, and 1300 TON. They also catalyze cyclopropanation of natural products with diastereoselectivities that are complementary to those attained with standard transition metal catalysts. Finally, Ir(Me)-PIX P450 variants react with substrate selectivity that is reminiscent of natural enzymes; they react preferentially with less reactive internal alkenes in the presence of more reactive terminal alkenes. Altogether, the studies reveal the suitability of Ir-containing P450s to combine the broad reactivity and substrate scope of transition metal catalysts with the exquisite selectivity of enzymes, generating catalysts that enable reactions to occur with levels and modes of activity and selectivity previously unattainable with natural enzymes or transition metal complexes alone.« less

Source Apportionment of Atmospheric Particles by Electron Probe X-Ray Microanalysis and Receptor Models.

NASA Astrophysics Data System (ADS)

van Borm, Werner August

Electron probe X-ray microanalysis (EPXMA) in combination with an automation system and an energy-dispersive X-ray detection system was used to analyse thousands of microscopical particles, originating from the ambient atmosphere. The huge amount of data was processed by a newly developed X-ray correction method and a number of data reduction procedures. A standardless ZAF procedure for EPXMA was developed for quick semi-quantitative analysis of particles starting from simple corrections, valid for bulk samples and modified taking into account the particle finit diameter, assuming a spherical shape. Tested on a limited database of bulk and particulate samples, the compromise between calculation speed and accuracy yielded for elements with Z > 14 accuracies on concentrations less than 10% while absolute deviations remained below 4 weight%, thus being only important for low concentrations. Next, the possibilities for the use of supervised and unsupervised multivariate particle classification were investigated for source apportionment of individual particles. In a detailed study of the unsupervised cluster analysis technique several aspects were considered, that have a severe influence on the final cluster analysis results, i.e. data acquisition, X-ray peak identification, data normalization, scaling, variable selection, similarity measure, cluster strategy, cluster significance and error propagation. A supervised approach was developed using an expert system-like approach in which identification rules are builded to describe the particle classes in a unique manner. Applications are presented for particles sampled (1) near a zinc smelter (Vieille-Montagne, Balen, Belgium), analyzed for heavy metals, (2) in an urban aerosol (Antwerp, Belgium), analyzed for over 20 elements and (3) in a rural aerosol originating from a swiss mountain area (Bern). Thus is was possible to pinpoint a number of known and unknown sources and characterize their emissions in terms of particles abundance and particle composition. Alternatively, the bulk analysis of filters (total, fine and coarse mode) using Particle Induced X -Ray Emission (PIXE) and the application of a receptor modeling approach provided for complementary information on a macroscopical level. A computer program was developed incorporating an absolute factor analysis based receptor modeling procedure. Source profiles and contributions are described by elemental concentrations and an atmospheric mass balance is put forward. The latter method was applied in a two year study of the Antwerp urban aerosol and for the swiss aerosol, revealing a number of previously known and unknown sources. Both methods were successfully combined to increase the source resolution.

Elastic recoil detection analysis for the determination of hydrogen concentration profiles in switchable mirrors

NASA Astrophysics Data System (ADS)

Huisman, M. C.; van der Molen, S. J.; Vis, R. D.

1999-10-01

Switchable mirrors [J.N. Huiberts, R. Griessen, J.H. Rector, R.J. Wijngaarden, J.P. Dekker, D.G. de Groot, N.J. Koeman, Nature 380 (1996) 231; J.N Huiberts, J.H. Rector, R.J. Wijngaarden, S. Jetten, D. de Groot, B. Dam, N.J.. Koeman, R. Griessen, B. Hjörvarsson, S Olafsson, Y.S. Cho, J. Alloys and Compounds 239 (1996) 158; F.J.A. den Broeder, S.J. van der Molen, M. Kremers, J. N. Huiberts, D.G. Nagengast, A.T.M. van Gogh, W.H. Huisman, N. J. Koeman, B. Dam, J.H. Rector, S. Plota, M. Haaksma, R.M.N. Hanzen, R.M. Jungblut, P.A. Duine, R. Griessen, Nature 394 (1998) 656] made of thin films of Y, La or rare-earth (RE) metals exhibit spectacular changes in their optical and electrical properties upon hydrogen loading. The study of these materials has indicated that the occurring phenomena are highly sensitive to the actual hydrogen concentration in these materials. In this paper elastic recoil detection analysis (ERDA) is used as a tool to measure hydrogen concentrations on a micrometer scale. The measurements have been performed using a 4He 2+ ion beam from a 1.7 MV Pelletron accelerator. The ion beam can be focused routinely to a spot size of approximately 10 μm 2. The experimental set-up enables the simultaneous measurement of Rutherford backscattering spectrometry (RBS) as well as particle induced X-ray emission (PIXE) spectra, which provide complementary information. The results of ERDA measurements on laterally diffused YH x (0< x<3) samples with a qualitatively known hydrogen concentration profile are presented and discussed. The calibration of the microbeam set-up and possible improvement of the measurement technique are described.

Contribution of ion beam analysis methods to the development of second generation high temperature superconducting wires

NASA Astrophysics Data System (ADS)

Usov, I. O.; Arendt, P. N.; Foltyn, S. R.; Stan, L.; DePaula, R. F.; Holesinger, T. G.

2010-06-01

One of the crucial steps in the second generation high temperature superconducting wire program was development of the buffer-layer architecture. The architecture designed at the Superconductivity Technology Center at Los Alamos National Laboratory consists of several oxide layers wherein each layer plays a specific role, namely: nucleation layer, diffusion barrier, biaxially textured template, and intermediate layer providing a suitable lattice match to the superconducting Y 1Ba 2Cu 3O 7 (YBCO) compound. This report demonstrates how a wide range of ion beam analysis techniques (SIMS, RBS, channeling, PIXE, PIGE, NRA and ERD) was employed for analysis of each buffer layer and the YBCO film. These results assisted in understanding of a variety of physical processes occurring during the buffer layer fabrication and helped to optimize the buffer-layer architecture as a whole.

Quantitative mapping of intracellular cations in the human amniotic membrane

NASA Astrophysics Data System (ADS)

Moretto, Ph.; Llabador, Y.; Simonoff, M.; Razafindrabe, L.; Bara, M.; Guiet-Bara, A.

1993-05-01

The effect of magnesium and taurine on the permeability of cell membranes to monovalent cations has been investigated using the Bordeaux nuclear microprobe. PIXE and RBS techniques have been used to provide quantitative measurements and ion distributions in the isolated amniotic membrane. This physiological model for cellular exchanges allowed us to reveal the distribution of most elements involved in cellular pathways and the modifications under different experimental conditions of incubation in physiological fluids. The PIXE microanalysis provided an original viewpoint on these mechanisms. Following this first study, the amnion compact lamina was found to play a role which was not, up to now, taken into account in the interpretation of electrophysiological experimentations. The release of some ionic species, such as K +, from the epithelial cells, during immersion in isotonic fluids, could have been hitherto underestimated.

Combined Non-invasive PIXE/PIGE Analyses of Mammoth Ivory from Aurignacian Archaeological Sites.

PubMed

Reiche, Ina; Heckel, Claire; Müller, Katharina; Jöris, Olaf; Matthies, Tim; Conard, Nicholas J; Floss, Harald; White, Randall

2018-06-18

Among the earliest Homo sapiens societies in Eurasia, the Aurignacian phase of the Early Upper Paleolithic, approximately 40 000-30 000 years ago, mammoth ivory assumed great social and economic significance, and was used to create hundreds of personal ornaments as well as the earliest known works of three-dimensional figurative art in the world. This paper reports on the results of micro-PIXE/PIGE analyses of mammoth-ivory artifacts and debris from five major sites of Aurignacian ivory use. Patterns of variable fluorine content indicate regionally distinctive strategies of ivory procurement that correspond to apparent differences in human-mammoth interactions. Preserved trace elements (Br, Sr, Zn) indicate that differences at the regional level are applicable to sourcing Paleolithic ivory at the regional scale. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Roman onyx glass: A study of production recipes and colorants, using PIXE spectrometry

NASA Astrophysics Data System (ADS)

Fleming, S. J.; Swann, C. P.

1994-03-01

The most attractive Roman glass produced during the latter half of the 1st century B.C. was mosaic ware — vessels and dishes molded from arrays of composite, multi-colored canes which create abstract floral and geometric designs. We have studied a range of such vessels, all of them colored amber and white in a way which was intended to imitate elite vessels that were carved from onyx stone. We have differentiated three ways in which onyx patterns were achieved in this glass. Taking advantage of the spatial resolution and detection sensitivity of PIXE spectrometry, we have studied the "recipes" for colorants used in these onyx patterns, thus raising the notion that each one may have been fashionable in just certain regions of the Roman World, and/or in vogue only during a certain time period.

An Apparatus For Student Projects Using External-Beam PIXE And PIGE

NASA Astrophysics Data System (ADS)

Correll, Francis D.; Edsall, Douglas W.; DePooter, Katherine A.; Maskell, Nicholas D.; Vanhoy, Jeffrey R.

2011-06-01

We recently installed a simple endstation at the Naval Academy Tandem Accelerator Laboratory to support student projects using external-beam PIXE and PIGE. It consists of a short, graphite-lined beamline extension with a thin window, an interlocked box that surrounds the target, detectors for x- and gamma rays, provision for flooding the target with helium gas, easily changed x-ray absorbers, and a compact video camera for monitoring the position of the beam spot. We used this system to measure the elemental composition of colonial-era architectural materials, principally bricks and mortar, from James Madison's Montpelier, the reconstructed Virginia estate of the fourth President of the United States. We describe the design and construction of the system, relate some of our experiences using it, and present some preliminary data from our investigations.

SymPix: A Spherical Grid for Efficient Sampling of Rotationally Invariant Operators

NASA Astrophysics Data System (ADS)

Seljebotn, D. S.; Eriksen, H. K.

2016-02-01

We present SymPix, a special-purpose spherical grid optimized for efficiently sampling rotationally invariant linear operators. This grid is conceptually similar to the Gauss-Legendre (GL) grid, aligning sample points with iso-latitude rings located on Legendre polynomial zeros. Unlike the GL grid, however, the number of grid points per ring varies as a function of latitude, avoiding expensive oversampling near the poles and ensuring nearly equal sky area per grid point. The ratio between the number of grid points in two neighboring rings is required to be a low-order rational number (3, 2, 1, 4/3, 5/4, or 6/5) to maintain a high degree of symmetries. Our main motivation for this grid is to solve linear systems using multi-grid methods, and to construct efficient preconditioners through pixel-space sampling of the linear operator in question. As a benchmark and representative example, we compute a preconditioner for a linear system that involves the operator \\widehat{{\\boldsymbol{D}}}+{\\widehat{{\\boldsymbol{B}}}}T{{\\boldsymbol{N}}}-1\\widehat{{\\boldsymbol{B}}}, where \\widehat{{\\boldsymbol{B}}} and \\widehat{{\\boldsymbol{D}}} may be described as both local and rotationally invariant operators, and {\\boldsymbol{N}} is diagonal in the pixel domain. For a bandwidth limit of {{\\ell }}{max} = 3000, we find that our new SymPix implementation yields average speed-ups of 360 and 23 for {\\widehat{{\\boldsymbol{B}}}}T{{\\boldsymbol{N}}}-1\\widehat{{\\boldsymbol{B}}} and \\widehat{{\\boldsymbol{D}}}, respectively, compared with the previous state-of-the-art implementation.

Retargeting of adenovirus vectors through genetic fusion of a single-chain or single-domain antibody to capsid protein IX.

PubMed

Poulin, Kathy L; Lanthier, Robert M; Smith, Adam C; Christou, Carin; Risco Quiroz, Milagros; Powell, Karen L; O'Meara, Ryan W; Kothary, Rashmi; Lorimer, Ian A; Parks, Robin J

2010-10-01

Adenovirus (Ad) vectors are the most commonly used system for gene therapy applications, due in part to their ability to infect a wide array of cell types and tissues. However, many therapies would benefit from the ability to target the Ad vector only to specific cells, such as tumor cells for cancer gene therapy. In this study, we investigated the utility of capsid protein IX (pIX) as a platform for the presentation of single-chain variable-fragment antibodies (scFv) and single-domain antibodies (sdAb) for virus retargeting. We show that scFv can be displayed on the capsid through genetic fusion to native pIX but that these molecules fail to retarget the virus, due to improper folding of the scFv. Redirecting expression of the fusion protein to the endoplasmic reticulum (ER) results in correct folding of the scFv and allows it to recognize its epitope; however, ER-targeted pIX-scFv was incorporated into the Ad capsid at a very low level which was not sufficient to retarget virus infection. In contrast, a pIX-sdAb construct was efficiently incorporated into the Ad capsid and enhanced virus infection of cells expressing the targeted receptor. Taken together, our data indicate that pIX is an effective platform for presentation of large targeting polypeptides on the surface of the virus capsid, but the nature of the ligand can significantly affect its association with virions.

The Capodimonte Deep Field

NASA Astrophysics Data System (ADS)

2001-04-01

A Window towards the Distant Universe Summary The Osservatorio Astronomico Capodimonte Deep Field (OACDF) is a multi-colour imaging survey project that is opening a new window towards the distant universe. It is conducted with the ESO Wide Field Imager (WFI) , a 67-million pixel advanced camera attached to the MPG/ESO 2.2-m telescope at the La Silla Observatory (Chile). As a pilot project at the Osservatorio Astronomico di Capodimonte (OAC) [1], the OACDF aims at providing a large photometric database for deep extragalactic studies, with important by-products for galactic and planetary research. Moreover, it also serves to gather experience in the proper and efficient handling of very large data sets, preparing for the arrival of the VLT Survey Telescope (VST) with the 1 x 1 degree 2 OmegaCam facility. PR Photo 15a/01 : Colour composite of the OACDF2 field . PR Photo 15b/01 : Interacting galaxies in the OACDF2 field. PR Photo 15c/01 : Spiral galaxy and nebulous object in the OACDF2 field. PR Photo 15d/01 : A galaxy cluster in the OACDF2 field. PR Photo 15e/01 : Another galaxy cluster in the OACDF2 field. PR Photo 15f/01 : An elliptical galaxy in the OACDF2 field. The Capodimonte Deep Field ESO PR Photo 15a/01 ESO PR Photo 15a/01 [Preview - JPEG: 400 x 426 pix - 73k] [Normal - JPEG: 800 x 851 pix - 736k] [Hi-Res - JPEG: 3000 x 3190 pix - 7.3M] Caption : This three-colour image of about 1/4 of the Capodimonte Deep Field (OACDF) was obtained with the Wide-Field Imager (WFI) on the MPG/ESO 2.2-m telescope at the la Silla Observatory. It covers "OACDF Subfield no. 2 (OACDF2)" with an area of about 35 x 32 arcmin 2 (about the size of the full moon), and it is one of the "deepest" wide-field images ever obtained. Technical information about this photo is available below. With the comparatively few large telescopes available in the world, it is not possible to study the Universe to its outmost limits in all directions. Instead, astronomers try to obtain the most detailed information possible in selected viewing directions, assuming that what they find there is representative for the Universe as a whole. This is the philosophy behind the so-called "deep-field" projects that subject small areas of the sky to intensive observations with different telescopes and methods. The astronomers determine the properties of the objects seen, as well as their distances and are then able to obtain a map of the space within the corresponding cone-of-view (the "pencil beam"). Recent, successful examples of this technique are the "Hubble Deep Field" (cf. ESO PR Photo 26/98 ) and the "Chandra Deep Field" ( ESO PR 05/01 ). In this context, the Capodimonte Deep Field (OACDF) is a pilot research project, now underway at the Osservatorio Astronomico di Capodimonte (OAC) in Napoli (Italy). It is a multi-colour imaging survey performed with the Wide Field Imager (WFI) , a 67-million pixel (8k x 8k) digital camera that is installed at the 2.2-m MPG/ESO Telescope at ESO's La Silla Observatory in Chile. The scientific goal of the OACDF is to provide an important database for subsequent extragalactic, galactic and planetary studies. It will allow the astronomers at OAC - who are involved in the VLT Survey Telescope (VST) project - to gain insight into the processing (and use) of the large data flow from a camera similar to, but four times smaller than the OmegaCam wide-field camera that will be installed at the VST. The field selection for the OACDF was based on the following criteria: * There must be no stars brighter than about 9th magnitude in the field, in order to avoid saturation of the CCD detector and effects from straylight in the telescope and camera. No Solar System planets should be near the field during the observations; * It must be located far from the Milky Way plane (at high galactic latitude) in order to reduce the number of galactic stars seen in this direction; * It must be located in the southern sky in order to optimize observing conditions (in particular, the altitude of the field above the horizon), as seen from the La Silla and Paranal sites; * There should be little interstellar material in this direction that may obscure the view towards the distant Universe; * Observations in this field should have been made with the Hubble Space Telescope (HST) that may serve for comparison and calibration purposes. Based on these criteria, the astronomers selected a field measuring about 1 x 1 deg 2 in the southern constellation of Corvus (The Raven). This is now known as the Capodimonte Deep Field (OACDF) . The above photo ( PR Photo 15a/01 ) covers one-quarter of the full field (Subfield No. 2 - OACDF2) - some of the objects seen in this area are shown below in more detail. More than 35,000 objects have been found in this area; the faintest are nearly 100 million fainter than what can be perceived with the unaided eye in the dark sky. Selected objects in the Capodimonte Deep Field ESO PR Photo 15b/01 ESO PR Photo 15b/01 [Preview - JPEG: 400 x 435 pix - 60k] [Normal - JPEG: 800 x 870 pix - 738k] [Hi-Res - JPEG: 3000 x 3261 pix - 5.1M] Caption : Enlargement of the interacting galaxies that are seen in the upper left corner of the OACDF2 field shown in PR Photo 15a/01 . The enlargement covers 1250 x 1130 WFI pixels (1 pixel = 0.24 arcsec), or about 5.0 x 4.5 arcmin 2 in the sky. The lower spiral is itself an interactive double. ESO PR Photo 15c/01 ESO PR Photo 15c/01 [Preview - JPEG: 557 x 400 pix - 93k] [Normal - JPEG: 1113 x 800 pix - 937k] [Hi-Res - JPEG: 3000 x 2156 pix - 4.0M] Caption : Enlargement of a spiral galaxy and a nebulous object in this area. The field shown covers 1250 x 750 pixels, or about 5 x 3 arcmin 2 in the sky. Note the very red objects next to the two bright stars in the lower-right corner. The colours of these objects are consistent with those of spheroidal galaxies at intermediate distances (redshifts). ESO PR Photo 15d/01 ESO PR Photo 15d/01 [Preview - JPEG: 400 x 530 pix - 68k] [Normal - JPEG: 800 x 1060 pix - 870k] [Hi-Res - JPEG: 2768 x 3668 pix - 6.2M] Caption : A further enlargement of a galaxy cluster of which most members are located in the north-east quadrant (upper left) and have a reddish colour. The nebulous object to the upper left is a dwarf galaxy of spheroidal shape. The red object, located near the centre of the field and resembling a double star, is very likely a gravitational lens [2]. Some of the very red, point-like objects in the field may be distant quasars, very-low mass stars or, possibly, relatively nearby brown dwarf stars. The field shown covers 1380 x 1630 pixels, or 5.5 x 6.5 arcmin 2. ESO PR Photo 15e/01 ESO PR Photo 15e/01 [Preview - JPEG: 400 x 418 pix - 56k] [Normal - JPEG: 800 x 835 pix - 700k] [Hi-Res - JPEG: 3000 x 3131 pix - 5.0M] Caption : Enlargement of a moderately distant galaxy cluster in the south-east quadrant (lower left) of the OACDF2 field. The field measures 1380 x 1260 pixels, or about 5.5 x 5.0 arcmin 2 in the sky. ESO PR Photo 15f/01 ESO PR Photo 15f/01 [Preview - JPEG: 449 x 400 pix - 68k] [Normal - JPEG: 897 x 800 pix - 799k] [Hi-Res - JPEG: 3000 x 2675 pix - 5.6M] Caption : Enlargement of the elliptical galaxy that is located to the west (right) in the OACDF2 field. The numerous tiny objects surrounding the galaxy may be globular clusters. The fuzzy object on the right edge of the field may be a dwarf spheroidal galaxy. The size of the field is about 6 x 5 arcmin 2. Technical Information about the OACDF Survey The observations for the OACDF project were performed in three different ESO periods (18-22 April 1999, 7-12 March 2000 and 26-30 April 2000). Some 100 Gbyte of raw data were collected during each of the three observing runs. The first OACDF run was done just after the commissioning of the ESO-WFI. The observational strategy was to perform a 1 x 1 deg 2 short-exposure ("shallow") survey and then a 0.5 x 1 deg 2 "deep" survey. The shallow survey was performed in the B, V, R and I broad-band filters. Four adjacent 30 x 30 arcmin 2 fields, together covering a 1 x 1 deg 2 field in the sky, were observed for the shallow survey. Two of these fields were chosen for the 0.5 x 1 deg 2 deep survey; OACDF2 shown above is one of these. The deep survey was performed in the B, V, R broad-bands and in other intermediate-band filters. The OACDF data are fully reduced and the catalogue extraction has started. A two-processor (500 Mhz each) DS20 machine with 100 Gbyte of hard disk, specifically acquired at the OAC for WFI data reduction, was used. The detailed guidelines of the data reduction, as well as the catalogue extraction, are reported in a research paper that will appear in the European research journal Astronomy & Astrophysics . Notes [1]: The team members are: Massimo Capaccioli, Juan M. Alcala', Roberto Silvotti, Magda Arnaboldi, Vincenzo Ripepi, Emanuella Puddu, Massimo Dall'Ora, Giuseppe Longo and Roberto Scaramella . [2]: This is a preliminary result by Juan Alcala', Massimo Capaccioli, Giuseppe Longo, Mikhail Sazhin, Roberto Silvotti and Vincenzo Testa , based on recent observations with the Telescopio Nazionale Galileo (TNG) which show that the spectra of the two objects are identical. Technical information about the photos PR Photo 15a/01 has been obtained by the combination of the B, V, and R stacked images of the OACDF2 field. The total exposure times in the three bands are 2 hours in B and V (12 ditherings of 10 min each were stacked to produce the B and V images) and 3 hours in R (13 ditherings of 15 min each). The mosaic images in the B and V bands were aligned relative to the R-band image and adjusted to a logarithmic intensity scale prior to the combination. The typical seeing was of the order of 1 arcsec in each of the three bands. Preliminary estimates of the three-sigma limiting magnitudes in B, V and R indicate 25.5, 25.0 and 25.0, respectively. More than 35,000 objects are detected above the three-sigma level. PR Photos 15b-f/01 display selected areas of the field shown in PR Photo 15a/01 at the original WFI scale, hereby also demonstrating the enormous amount of information contained in these wide-field images. In all photos, North is up and East is left.

GUMAP: A GUPIXWIN-compatible code for extracting regional spectra from nuclear microbeam list mode files

NASA Astrophysics Data System (ADS)

Russell, John L.; Campbell, John L.; Boyd, Nicholas I.; Dias, Johnny F.

2018-02-01

The newly developed GUMAP software creates element maps from OMDAQ list mode files, displays these maps individually or collectively, and facilitates on-screen definitions of specified regions from which a PIXE spectrum can be built. These include a free-hand region defined by moving the cursor. The regional charge is entered automatically into the spectrum file in a new GUPIXWIN-compatible format, enabling a GUPIXWIN analysis of the spectrum. The code defaults to the OMDAQ dead time treatment but also facilitates two other methods for dead time correction in sample regions with count rates different from the average.

Analysis of garnets from the archaeological sites in Slovenia

NASA Astrophysics Data System (ADS)

Šmit, Ž.; Fajfar, H.; Jeršek, M.; Knific, T.; Lux, J.

2014-06-01

Garnets (62 individual stones) originating from the Migration Period cemeteries and hilltop settlements in Slovenia were analyzed by the combined PIXE/PIGE method for their chemical composition. Typologically, the analyzed stones may be classified as almandines originating from the sites in India, belonging to types I and II according to Calligaro. A smaller group of pyraldines intermediate between almandines and pyropes was also determined; identified as type III, their source is most likely in Sri Lanka. No garnets from Bohemia (Czech Republic) have been discovered, which may be related to important political changes in the 7th c. AD, induced by Slavic and Avaric migrations.

Iba Techniques to Study Renaissance Pottery Techniques

NASA Astrophysics Data System (ADS)

Bouquillon, A.; Castaing, J.; Salomon, J.; Zucchiatti, A.; Lucarelli, F.; Mando, P. A.; Prati, P.; Lanterna, G.; Vaccari, M. G.

2001-09-01

The application of Ion Beam Analysis, associated to Scanning Electron Microscopy is examined in connection with an extensive program on structural and chemical analyses of glazed terracotta's from the Italian Renaissance, launched by a French-Italian collaboration in the framework of the European COST-G1 scientific action. The objectives of the collaboration are reviewed. The compatibility of data from different specimen and various laboratories are discussed. Examples of the PIXE and statistical analyses on some artefacts of the "Robbiesche" type, supplied by the Louvre Museum of Paris and the Opificio delle Pietre Dure of Florence, are given to illustrate the performances of IBA in this particular field.

The Columbia University proton-induced soft x-ray microbeam.

PubMed

Harken, Andrew D; Randers-Pehrson, Gerhard; Johnson, Gary W; Brenner, David J

2011-09-15

A soft x-ray microbeam using proton-induced x-ray emission (PIXE) of characteristic titanium (K(α) 4.5 keV) as the x-ray source has been developed at the Radiological Research Accelerator Facility (RARAF) at Columbia University. The proton beam is focused to a 120 μm × 50 μm spot on the titanium target using an electrostatic quadrupole quadruplet previously used for the charged particle microbeam studies at RARAF. The proton induced x-rays from this spot project a 50 μm round x-ray generation spot into the vertical direction. The x-rays are focused to a spot size of 5 μm in diameter using a Fresnel zone plate. The x-rays have an attenuation length of (1/e length of ~145 μm) allowing more consistent dose delivery across the depth of a single cell layer and penetration into tissue samples than previous ultra soft x-ray systems. The irradiation end station is based on our previous design to allow quick comparison to charged particle experiments and for mixed irradiation experiments.

Electronic wave function and binding effects in M-shell ionization of gold by protons

NASA Astrophysics Data System (ADS)

Pajek, M.; Banaś, D.; Jabłoński, Ł.; Mukoyama, T.

2018-02-01

The measured M-X-ray production cross sections for protons, which are used in the particle induced X-ray emission (PIXE) technique, are systematically underestimated for low impact energies by the ECPSSR and ECUSAR theories. These theories, which are based on the plane wave Born approximation (PWBA) and use the screened hydrogenic wave functions, include corrections for the projectile Coulomb deflection and electron relativistic and binding effects. In the present paper, in order to interpret the observed disagreement at low impact energies, the systematic calculations of the M-shell ionization cross sections for gold were performed using the semiclassical (SCA) and the binary encounter (BEA) approximations in order to identify a role of the electronic wave function and electron binding effects. In these calculations the different wave functions, from nonrelativistic hydrogenic to selfconsistent Dirac-Hartree-Fock, were considered and the binding effect was treated within extreme separated- (SA) and united-atoms (UA) limits. The results are discussed in details and the observed discrepancies are attributed to inadequate description of the electron binding effect at the lowest impact energies for which the molecular approach is required.

New type of capillary for use as ion beam collimator and air-vacuum interface

NASA Astrophysics Data System (ADS)

Stoytschew, V.; Schulte-Borchers, M.; Božičević Mihalića, Iva; Perez, R. D.

2016-08-01

Glass capillaries offer a unique way to combine small diameter ion beam collimation with an air-vacuum interface for ambient pressure ion beam applications. Usually they have an opening diameter of a few microns, limiting the air inflow sufficiently to maintain stable conditions on the vacuum side. As the glass capillaries generally are quite thin and fragile, handling of the capillary in the experiment becomes difficult. They also introduce an X-ray background produced by the capillary wall material, which has to be shielded or subtracted from the data for Particle Induced X-ray Emission (PIXE) applications. To overcome both drawbacks, a new type of conical glass capillary has been developed. It has a higher wall thickness eliminating the low energy X-ray background produced by common capillaries and leading to a more robust lens. The results obtained in first tests show, that this new capillary is suitable for ion beam collimation and encourage further work on the capillary production process to provide thick wall capillaries with an outlet diameter in the single digit micro- or even nanometre range.

Fabrication and characterization of carbon-backed thin 208Pb targets.

PubMed

Thakur, Meenu; Dubey, R; Abhilash, S R; Behera, B R; Mohanty, B P; Kabiraj, D; Ojha, Sunil; Duggal, Heena

2016-01-01

Thin carbon-backed isotopically enriched 208 Pb targets were required for our experiment aimed to study the reaction dynamics for 48 Ti +  208 Pb system, populating the near super-heavy nucleus 256 Rf, through mass-energy correlation of the fission fragments. Purity and thickness of the targets are of utmost importance in such studies as these factors have strong influence on the measurement accuracy of mass and energy distribution of fission fragments. 208 Pb targets with thickness ranging from 60 μg/cm 2 to 250 μg/cm 2 have been fabricated in high vacuum environment using physical vapor deposition method. Important points in the method are as follows: • 208 Pb was deposited using resistive heating method, whereas carbon (backing foil) deposition was performed by using the electron beam bombardment technique.•Different characterization techniques such as Particle Induced X-ray Emission (PIXE), Energy Dispersive X-Ray Fluorescence (EDXRF) and Rutherford Backscattering Spectrometry (RBS) were used to assert the purity and thickness of the targets.•These targets have successfully been used to accomplish our experimental objectives.

Trace Element Studies on Tinospora cordifolia (Menispermaceae), Ocimum sanctum (Lamiaceae), Moringa oleifera (Moringaceae), and Phyllanthus niruri (Euphorbiaceae) Using PIXE.

PubMed

Gowrishankar, Ramadurai; Kumar, Manish; Menon, Vinay; Divi, Sai Mangala; Saravanan, M; Magudapathy, P; Panigrahi, B K; Nair, K G M; Venkataramaniah, K

2010-03-01

Traditionally, Tinospora cordifolia (Willd.) Hook. F. & Thomson (Menispermaceae), Ocimum sanctum L. (Lamiaceae), Moringa oleifera Lam. (Moringaceae), and Phyllanthus niruri L. (Euphorbiaceae) are some of the commonly used medicinal plants in India for curing ailments ranging from common cold, skin diseases, and dental infections to major disorders like diabetes, hypertension, jaundice, rheumatism, etc. To understand and correlate their medicinal use, trace element studies on the aqueous extract of these medicinal plants have been carried out using particle-induced X-ray emission technique. A 2-MeV proton beam was used to identify and characterize major and minor elements namely Cl, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Br, and Sr in them. Results have revealed that these elements are present in varying concentrations in the selected plants. Notable results include very high concentrations of Cl, K, and Ca in all the leaf samples, appreciable levels of Mn in all plants, high Zn content in T. cordifolia, and the aqueous extract of Moringa leaves compared to others and relative higher concentrations of Cr in all the plants.

Metal imaging in neurodegenerative diseases

PubMed Central

Bourassa, Megan W.

2014-01-01

Metal ions are known to play an important role in many neurodegenerative diseases including Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), and prion diseases. In these diseases, aberrant metal binding or improper regulation of redox active metal ions can induce oxidative stress by producing cytotoxic reactive oxygen species (ROS). Altered metal homeostasis is also frequently seen in the diseased state. As a result, the imaging of metals in intact biological cells and tissues has been very important for understanding the role of metals in neurodegenerative diseases. A wide range of imaging techniques have been utilized, including X-ray fluorescence microscopy (XFM), particle induced X-ray emission (PIXE), energy dispersive X-ray spectroscopy (EDS), laser ablation inductively coupled mass spectrometry (LA-ICP-MS), and secondary ion mass spectrometry (SIMS), all of which allow for the imaging of metals in biological specimens with high spatial resolution and detection sensitivity. These techniques represent unique tools for advancing the understanding of the disease mechanisms and for identifying possible targets for developing treatments. In this review, we will highlight the advances in neurodegenerative disease research facilitated by metal imaging techniques. PMID:22797194

Bioaccumulation of nickel by intercalation into polycrystalline hydrogen uranyl phosphate deposited via an enzymatic mechanism.

PubMed

Bonthrone, K M; Basnakova, G; Lin, F; Macaskie, L E

1996-05-01

A Citrobacter sp. accumulates uranyl ion (UO2(2+)) as crystalline HUO2PO4.4H2O (HUP), using enzymatically generated inorganic phosphate. Ni was not removed by this mechanism, but cells already loaded with HUP removed Ni2+ by intercalative ion-exchange, forming Ni(UO2PO4)2.7H2O, as concluded by x-ray diffraction (XRD) and proton induced x-ray emission (PIXE) analyses. The loaded biomass became saturated with Ni rapidly, with a molar ratio of Ni:U in the cellbound deposit of approx. 1:6; Ni penetration was probably surface-localized. Cochallenge of the cells with Ni2+ and UO2(2+), and glycerol 2-phosphate (phosphate donor for phosphate release and metal bioprecipitation) gave sustained removal of both metals in a flow through bioreactor, with more extensively accumulated Ni. We propose 'Microbially Enhanced Chemisorption of Heavy Metals' (MECHM) to describe this hybrid mechanism of metal bioaccumulation via intercalation into preformed, biogenic crystals, and note also that MECHM can promote the removal of the transuranic radionuclide neptunium, which is difficult to achieve by conventional methods.

Effects of Supplemental Acerola Juice on the Mineral Concentrations in Liver and Kidney Tissue Samples of Mice Fed with Cafeteria Diet.

PubMed

Leffa, Daniela Dimer; dos Santos, Carla Eliete Iochims; Daumann, Francine; Longaretti, Luiza Martins; Amaral, Livio; Dias, Johnny Ferraz; da Silva, Juliana; Andrade, Vanessa Moraes

2015-09-01

We evaluated the impact of a supplemental acerola juice (unripe, ripe, and industrial) and its main pharmaceutically active components on the concentrations of minerals in the liver and kidney of mice fed with cafeteria diet. Swiss male mice were fed with a cafeteria (CAF) diet for 13 weeks. The CAF consisted of a variety of supermarket products with high energy content. Subsequently, animals received one of the following food supplements for 1 month: water, unripe acerola juice, ripe acerola juice, industrial acerola juice, vitamin C, or rutin. Mineral concentrations of the tissues were determined by particle-induced X-ray emission (PIXE). Our study suggests that the simultaneous intake of acerola juices, vitamin C, or rutin in association with a hypercaloric and hyperlipidic diet provides change in the mineral composition of organisms in the conditions of this study, which plays an important role in the antioxidant defenses of the body. This may help to reduce the metabolism of the fat tissue or even to reduce the oxidative stress.

Computer simulation of the CSPAD, ePix10k, and RayonixMX170HS X-ray detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tina, Adrienne

2015-08-21

The invention of free-electron lasers (FELs) has opened a door to an entirely new level of scientific research. The Linac Coherent Light Source (LCLS) at SLAC National Accelerator Laboratory is an X-ray FEL that houses several instruments, each with its own unique X-ray applications. This light source is revolutionary in that while its properties allow for a whole new range of scientific opportunities, it also poses numerous challenges. For example, the intensity of a focused X-ray beam is enough to damage a sample in one mere pulse; however, the pulse speed and extreme brightness of the source together are enoughmore » to obtain enough information about that sample, so that no further measurements are necessary. An important device in the radiation detection process, particularly for X-ray imaging, is the detector. The power of the LCLS X-rays has instigated a need for better performing detectors. The research conducted for this project consisted of the study of X-ray detectors to imitate their behaviors in a computer program. The analysis of the Rayonix MX170-HS, CSPAD, and ePix10k in particular helped to understand their properties. This program simulated the interaction of X-ray photons with these detectors to discern the patterns of their responses. A scientist’s selection process of a detector for a specific experiment is simplified from the characterization of the detectors in the program.« less

Monitoring Ion Track Formation Using In Situ RBS/c, ToF-ERDA, and HR-PIXE

NASA Astrophysics Data System (ADS)

Karlušić, Marko; Fazinić, Stjepko; Siketić, Zdravko; Tadić, Tonči; Cosic, Donny; Božičević-Mihalić, Iva; Zamboni, Ivana; Jakšić, Milko; Schleberger, Marika

2017-09-01

The aim of this work is to investigate feasibility of the ion beam analysis techniques for monitoring swift heavy ion track formation. First, use of the in situ Rutherford backscattering spectroscopy in channeling mode to observe damage build-up in quartz SiO2 after MeV heavy ion irradiation is demonstrated. Second, new results of the in situ grazing incidence time-of-flight elastic recoil detection analysis used for monitoring the surface elemental composition during ion tracks formation in various materials are presented. Ion tracks were found on SrTiO3, quartz SiO2, a-SiO2 and muscovite mica surfaces by atomic force microscopy, but in contrast to our previous studies on GaN and TiO2, surface stoichiometry remained unchanged.

Desert Pathfinder at Work

NASA Astrophysics Data System (ADS)

2005-09-01

The Atacama Pathfinder Experiment (APEX) project celebrates the inauguration of its outstanding 12-m telescope, located on the 5100m high Chajnantor plateau in the Atacama Desert (Chile). The APEX telescope, designed to work at sub-millimetre wavelengths, in the 0.2 to 1.5 mm range, passed successfully its Science Verification phase in July, and since then is performing regular science observations. This new front-line facility provides access to the "Cold Universe" with unprecedented sensitivity and image quality. After months of careful efforts to set up the telescope to work at the best possible technical level, those involved in the project are looking with satisfaction at the fruit of their labour: APEX is not only fully operational, it has already provided important scientific results. "The superb sensitivity of our detectors together with the excellence of the site allow fantastic observations that would not be possible with any other telescope in the world," said Karl Menten, Director of the group for Millimeter and Sub-Millimeter Astronomy at the Max-Planck-Institute for Radio Astronomy (MPIfR) and Principal Investigator of the APEX project. ESO PR Photo 30/05 ESO PR Photo 30/05 Sub-Millimetre Image of a Stellar Cradle [Preview - JPEG: 400 x 627 pix - 200k] [Normal - JPEG: 800 x 1254 pix - 503k] [Full Res - JPEG: 1539 x 2413 pix - 1.3M] Caption: ESO PR Photo 30/05 is an image of the giant molecular cloud G327 taken with APEX. More than 5000 spectra were taken in the J=3-2 line of the carbon monoxide molecule (CO), one of the best tracers of molecular clouds, in which star formation takes place. The bright peak in the north of the cloud is an evolved star forming region, where the gas is heated by a cluster of new stars. The most interesting region in the image is totally inconspicuous in CO: the G327 hot core, as seen in methanol contours. It is a truly exceptional source, and is one of the richest sources of emission from complex organic molecules in the Galaxy (see spectrum at bottom). Credit: Wyrowski et al. (map), Bisschop et al. (spectrum). Millimetre and sub-millimetre astronomy opens exciting new possibility in the study of the first galaxies to have formed in the Universe and of the formation processes of stars and planets. In particular, APEX allows astronomers to study the chemistry and physical conditions of molecular clouds, that is, dense regions of gas and dust in which new stars are forming. Among the first studies made with APEX, astronomers took a first glimpse deep into cradles of massive stars, observing for example the molecular cloud G327 and measuring significant emission in carbon monoxide and complex organic molecules (see ESO PR Photo 30/05). The official inauguration of the APEX telescope will start in San Pedro de Atacama on September, 25th. The Ambassadors in Chile of some of ESO's member states, the Intendente of the Chilean Region II, the Mayor of San Pedro, the Executive Director of the Chilean Science Agency (CONICYT), the Presidents of the Communities of Sequitor and Toconao, as well as representatives of the Ministry of Foreign Affairs and Universities in Chile, will join ESO's Director General, Dr. Catherine Cesarsky, the Chairman of the APEX Board and MPIfR director, Prof. Karl Menten, and the Director of the Onsala Space Observatory, Prof. Roy Booth, in a celebration that will be held in San Pedro de Atacama. The next day, the delegation will visit the APEX base camp in Sequitor, near San Pedro, from where the telescope is operated, as well as the APEX site on the 5100m high Llano de Chajnantor.

Micro-PIXE mapping of elemental distribution in arbuscular mycorrhizal roots of the grass, Cynodon dactylon, from gold and uranium mine tailings

NASA Astrophysics Data System (ADS)

Weiersbye, I. M.; Straker, C. J.; Przybylowicz, W. J.

1999-10-01

A combination of PIXE, proton back-scattering (BS) spectrometry and confocal laser scanning microscopy (CLSM) was used to determine in situ elemental concentrations in arbuscular mycorrhizal (AM) grass roots and AM fungal spores from gold and uranium mine tailings in South Africa. AM regions of roots were characterised by locally elevated P and vesicles were defined by distinctive transition metal and radionuclide distributions. Vesicles (AM structures responsible for nutrient storage), accumulated Mn, Cu, Ni and U, whereas Fe and Zn were present at lower levels than in host tissue. AM spores from mine tailings accumulated Ca, Cr, Fe, Ni, Cu, Br, Y, Th and U, but were deficient in P and K. The sequestration of excess metals and radionuclides in vesicles may limit metal availability, and thus toxicity, to the host.

Study of the atmospheric aerosol composition in equatorial Africa using PIXE as analytical technique

NASA Astrophysics Data System (ADS)

Maenhaut, W.; Akilimali, K.

1987-03-01

Small Nuclepore total filter holders and a single orifice 8-stage cascade impactor were used to collect atmospheric aerosol samples in Kinshasa, Zaire, and Butare, Rwanda. The samples were analyzed for about 20 elements by means of the PIXE technique. The results obtained for parallel samples, taken with two total filter holders and one cascade impactor, were generally in excellent agreement, suggesting that the different samplers collected very similar aerosol particle populations. Most elements were associated with a crustal dust dispersion source, which may include road dust dispersal. The Butare samples, particularly those collected during the night, were significantly influenced by biomass burning, as was deduced from enhanced filter blackness and noncrustal K levels. The pyrogenic component also contained P, S, Mn and Rb. Br and Pb were highly enriched at both locations, indicating that automotive sources had a strong influence on the aerosol composition.

Studies on bronze pre-monetary signs found in Dobroudja using XRF and micro-PIXE

NASA Astrophysics Data System (ADS)

Constantinescu, B.; Cristea-Stan, D.; Talmatchi, G.; Ceccato, D.

2016-03-01

We performed compositional analyses on 180 Scythian-type arrowheads and pre-monetary signs using XRF method and on 60 small fragments of such items (approx. 100 microns diameter), sampling being performed on previously corrosion-cleaned areas on their surface, using micro-PIXE. The items are found in Dobroudja, Istros-Histria region. The most relevant for numismatists result is that for each finding place the same type of alloy was used both for fighting arrowheads and for pre-monetary signs. Our analyses revealed three types of alloys: Cu-Sn-Pb ("normal" bronze), Cu-Sn-Mn-Pb and Cu-Sn-Sb-Pb. The presence of antimony suggests the use of fahlore-type poly-metals deposits, most probably from Caucasus Mountains. The problem of ancient bronze containing manganese is more complicated; an explanation could be the use of manganese oxides as flux necessary to smelt oxidized ores.

An ion accelerator for undergraduate research and teaching

NASA Astrophysics Data System (ADS)

Monce, Michael

1997-04-01

We have recently upgraded our 400kV, single beam line ion accelerator to a 1MV, multiple beam line machine. This upgrade has greatly expanded the opportunities for student involvement in the laboratory. We will describe four areas of work in which students now participate. The first is the continuing research being conducted in excitations produced in ion-molecule collisions, which recently involved the use of digital imaging. The second area of research now opened up by the new accelerator involves PIXE. We are currently beginning a cross disciplinary study of archaeological specimens using PIXE and involving students from both anthropology and physics. Finally, two beam lines from the accelerator will be used for basic work in nuclear physics: Rutherford scattering and nuclear resonances. These two nuclear physics experiments will be integrated into our sophomore-junior level, year-long course in experimental physics.

Investigation of strontium accumulation on ovariectomized Sprague-Dawley rat tibia by micro-PIXE

NASA Astrophysics Data System (ADS)

Li, X.; Li, Y.; Jin, W.; Zheng, Y.; Rong, C.; Lyu, H.; Shen, H.

2014-08-01

Strontium ranelate is a newly developed drug effective in osteoporosis treatment by depressing bone resorption and maintaining bone formation. Strontium accumulation and distribution are determined in bones of rat after strontium ranelate administration by using micro-PIXE. The investigated rats are divided into four groups: (A) control, (B) ovariectomized, (C) ovariectomized followed with strontium chloride, (D) ovariectomized followed with strontium ranelate. It was found that strontium ranelate would result in increasing trabecular volume and decreasing bone resorption to treat osteoporosis. There are similar contours of calcium and strontium in two-dimensional images, while the strontium is not evenly distributed in the bone. It supports the conclusion that strontium has an affinity for bone and it is capable of replacing calcium atoms as a part of the strontium mechanism in the osteoporosis treatment. The results related to biochemistry are also discussed.

Application of PIXE to the study of Renaissance style enamelled gold jewelry

NASA Astrophysics Data System (ADS)

Weldon, M.; Carlson, J.; Reedy, S.; Swann, C. P.

1996-04-01

This study examines and compares three pieces of Renaissance style gold and enamelled jewelry owned by the Walters Art Gallery, Baltimore, MD, USA. These are a 16th century Hat Badge of Adam and Eve, a 19th century Fortitude Pendant and a Diana Pendant presumed to be of the 16th century (The Walters Art Gallery, Jewelry, Ancient to Modern (Viking, New York, 1979)), Ref. [1]. PIXE spectroscopy was applied to examine the elemental composition of the gold and of the enamels. Compositional differences, including the use of post-Renaissance colorants, were found between the enamels in separate regions of each of the three pieces. The modern colorant, chromium, was, in fact, found in all of the pieces and uranium was found in only the Diana Pendant. There are some differences in the gold purity of the three objects; there are significant differences in the solders used even within one object, the Fortitude Pendant.

Elemental analyses of pine bark and wood in an environmental study.

PubMed

Saarela, K-E; Harju, L; Rajander, J; Lill, J-O; Heselius, S-J; Lindroos, A; Mattsson, K

2005-05-01

Bark and wood samples were taken from the same individuals of Scots pine (Pinus sylvestris L.) from a polluted area close to a Cu-Ni smelter in Harjavalta and from some relatively unpolluted areas in western Finland. The samples were analysed by thick-target particle induced X-ray emission (PIXE) after preconcentration by dry ashing at 550 degrees C. The elemental contents of pine bark and wood were compared to study the impact of heavy metal pollution on pine trees. By comparison of the elemental contents in ashes of bark and wood, a normalisation was obtained. For the relatively clean areas, the ratios of the concentration in bark ash to the concentration in wood ash for different elements were close to 1. This means that the ashes of Scots Pine wood and bark have quite similar elemental composition. For the samples from the polluted area the mean concentration ratios for some heavy metals were elevated (13-28), reflecting the effect of direct atmospheric contamination. The metal contents in the ashes of pine bark and wood were also compared to recommendations for ashes to be recycled back to the forest environment. Bark from areas close to emission sources of heavy metal pollution should be considered with caution if aiming at recycling the ash. Burning of bark fuel of pine grown within 6 km of the Cu-Ni smelter is shown to generate ashes with high levels of Cu, Ni as well as Cd, As and Pb.

Synchrotron and ion beam studies of the bone-cartilage interface

NASA Astrophysics Data System (ADS)

Bradley, D. A.; Kaabar, W.; Gundogdu, O.; Farquharson, M. J.; Janousch, M.; Bailey, M.; Jeynes, C.

2010-07-01

The divalent cations Ca, P and Zn have been reported to play an important role in the normal growth and remodelling of articular cartilage and subchondral bone and in the degenerative and inflammatory processes associated with osteoarthritis (OA). In particular, they act as co-factors of a class of enzymes known as metalloproteinases, believed to be active during the initiation, progress and remodelling processes associated with the disease. The relative presence of cations and anions, in particular the ions Na 2+ and Cl -, is also intimately associated with the fixed charge density (FCD) of cartilage, neutralizing the highly charged structure associated with for instance chondroitin sulphate. Finally, structural components of bone can be expected to result from dietary intake, yielding for instance strontium apatite and fluorapatite that form inclusions in the calcium hydroxyapatite of bone. In the present investigation, thin sections of articular cartilage affected by OA have been examined using a combination of physical techniques: low energy synchrotron micro X-ray fluorescence (μ-SXRF), micro proton induced X-ray emission (μ-PIXE) and micro proton-induced gamma emission (μ-PIGE), primarily to investigate the distribution of essential cations and anions. The combination of these physical techniques offers the ability to make comprehensive assessment of the elemental content of such tissues, simultaneous mappings of a range of relatively low atomic number ions being obtained over quite large areas (˜few mm 2). Such capability has only become a realistic prospect in recent times.

Nuclear analytical techniques in medicine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cesareo, R.

1988-01-01

This book acquaints one with the fundamental principles and the instrumentation relevant to analytical technique based on atomic and nuclear physics, as well as present and future biomedical applications. Besides providing a theoretical description of the physical phenomena, a large part of the book is devoted to applications in the medical and biological field, particularly in hematology, forensic medicine and environmental science. This volume reviews methods such as the possibility of carrying out rapid multi-element analysis of trace elements on biomedical samples, in vitro and in vivo, by XRF-analysis; the ability of the PIXE-microprobe to analyze in detail and tomore » map trace elements in fragments of biomedical samples or inside the cells; the potentiality of in vivo nuclear activation analysis for diagnostic purposes. Finally, techniques are described such as radiation scattering (elastic and inelastic scattering) and attenuation measurements which will undoubtedly see great development in the immediate future.« less

An efficient ionoluminescence analysis of turquoise gemstone as a weakly luminescent mineral.

PubMed

Nikbakht, T; Kakuee, O; Lamehi-Rachti, M

2017-05-15

The unique ionization pattern of MeV-energy ion beam is applied for efficient luminescence analysis of a collection of natural turquoise samples. The considerable penetration depth of tens of micrometer and enhancement of energy deposition with depth, suggests ionoluminescence as an appropriate technique for studying weakly luminescent minerals. Herein, the luminescence induced in deeper parts of turquoise samples is extracted through their relatively transparent adjacent host stones. The resulting intense spectra reveal the vibrational structure of the broad green luminescence band of turquoise which probably originates from O 2 - centers. Moreover, owing to the applied ionoluminescence approach, red and blue luminescence bands of turquoise were observed which can be ascribed to Fe 3+ ions and UO 2 2+ centers respectively. The elemental information of the samples is provided using micro-PIXE analysis technique. Copyright © 2017 Elsevier B.V. All rights reserved.

Nuclear microanalysis of platinum and trace elements in cisplatin-resistant human ovarian adenocarcinoma cells

NASA Astrophysics Data System (ADS)

Moretto, P.; Ortega, R.; Llabador, Y.; Simonoff, M.; Bénard, J.; Moretto, Ph.

1995-09-01

Macro-and Micro-PIXE analysis were applied to study the mechanisms of cellular resistance to cisplatin, a chemotherapeutic agent, widely used nowadays for the treatment of ovarian cancer. Two cultured cell lines, a cisplatin-sensitive and a resistant one, were compared for their trace elements content and platinum accumulation following in vitro exposure to the drug. Bulk analysis revealed significant differences in copper and iron content between the two lines. Subsequent individual cell microanalysis permitted us to characterize the response of the different morphological cell types of the resistant line. This study showed that the metabolism of some trace metals in cisplatin-resistant cells could be affected but the exact relationship with the resistant phenotype remains to be determined. From a technical point of view, this experiment demonstrated that an accurate measurement of trace elements could be derived from nuclear microprobe analysis of individual cell.

Really Hot Stars

NASA Astrophysics Data System (ADS)

2003-04-01

Spectacular VLT Photos Unveil Mysterious Nebulae Summary Quite a few of the most beautiful objects in the Universe are still shrouded in mystery. Even though most of the nebulae of gas and dust in our vicinity are now rather well understood, there are some which continue to puzzle astronomers. This is the case of a small number of unusual nebulae that appear to be the subject of strong heating - in astronomical terminology, they present an amazingly "high degree of excitation". This is because they contain significant amounts of ions, i.e., atoms that have lost one or more of their electrons. Depending on the atoms involved and the number of electrons lost, this process bears witness to the strength of the radiation or to the impact of energetic particles. But what are the sources of that excitation? Could it be energetic stars or perhaps some kind of exotic objects inside these nebulae? How do these peculiar objects fit into the current picture of universal evolution? New observations of a number of such unusual nebulae have recently been obtained with the Very Large Telescope (VLT) at the ESO Paranal Observatory (Chile). In a dedicated search for the origin of their individual characteristics, a team of astronomers - mostly from the Institute of Astrophysics & Geophysics in Liège (Belgium) [1] - have secured the first detailed, highly revealing images of four highly ionized nebulae in the Magellanic Clouds, two small satellite galaxies of our home galaxy, the Milky Way, only a few hundred thousand light-years away. In three nebulae, they succeeded in identifying the sources of energetic radiation and to eludicate their exceptional properties: some of the hottest, most massive stars ever seen, some of which are double. With masses of more than 20 times that of the Sun and surface temperatures above 90 000 degrees, these stars are truly extreme. PR Photo 09a/03: Nebula around the hot star AB7 in the SMC. PR Photo 09b/03: Nebula near the hot Wolf-Rayet star BAT99-2 in the LMC. PR Photo 09c/03: Nebula near the hot binary star BAT99-49 in the LMC. PR Photo 09d/03: The N44C Nebula in the LMC. Four unique images of highly excited nebulae in the Magellanic Clouds ESO PR Photo 09a/03 ESO PR Photo 09a/03 [Preview - JPEG: 400 x 472 pix - 74k [Normal - JPEG: 800 x 943 pix - 720k] [Full-Res - JPEG: 1200 x 1414 pix - 1.2M] ESO PR Photo 09b/03 ESO PR Photo 09b/03 [Preview - JPEG: 400 x 466 pix - 70k [Normal - JPEG: 800 x 931 pix - 928k] [Full-Res - JPEG: 1200 x 1397 pix - 1.8M] ESO PR Photo 09c/03 ESO PR Photo 09c/03 [Preview - JPEG: 400 x 469 pix - 74k [Normal - JPEG: 800 x 937 pix - 1.1M] [Full-Res - JPEG: 1200 x 1405 pix - 2.2M] ESO PR Photo 09d/03 ESO PR Photo 09d/03 [Preview - JPEG: 400 x 473 pix - 28k [Normal - JPEG: 800 x 945 pix - 368k] [Full-Res - JPEG: 1200 x 1418 pix - 600k] Captions: PR Photo 09a/03 is a reproduction of a "near-true" three-colour composite image of the highly excited nebula around the hot double star AB7 in the Small Magellanic Cloud (SMC), obtained in January 2002 with the FORS1 multi-mode instrument at the 8.2-m VLT MELIPAL telescope at the Paranal Observatory (Chile). It is based on three exposures through narrow-band optical (interference) filters that isolate the light from specific atoms and ions. In this rendering, the blue colour represents the light from singly ionized Helium (He II; wavelength 468.6 nm; exposure time 30 min), green corresponds to doubly ionized oxygen ([O III]; 495.7 + 500.7 nm; 5 min) and red to hydrogen atoms (H; H-alpha line at 656.2 nm; 5 min). Of these three ions, He II is the tracer of high excitation, i.e. the bluest areas of the nebula are the hottest. The sky field measures 400 x 400 arcsec2; the original pixel size on the 2k x 2k CCD is 0.23 arcsec. North is up and east to the left. Before combination, the CCD frames were flat-fielded and cleaned of cosmic-rays. Moreover, the stars in the blue (He II) image were removed in order to provide a clearer view of the surrounding nebular emission. The reproduced brightness is proportional to the square-root of the actual intensity; this increases the "dynamical range" of the image, i.e. it shows better areas of very different brightness. PR Photo 09b/03 is a similar reproduction of the sky area with the nebula near the Wolf-Rayet (WR) star BAT99-2 in the LMC. The filters are the same, but the exposure times were 60, 5 and 5 min for the blue, green and red exposures, respectively. PR Photo 09c/03 shows, in the same way, the nebula around the hot double star BAT99-49 in the LMC. The filters are the same, but the exposure times were 45, 5 and 5 min for the blue, green and red exposures, respectively. Finally, PR Photo 09d/03 shows the N44C nebula in the LMC, photographed through the same optical filters with exposure times of 20, 5 and 5 min for the blue, green and red exposures, respectively. The sky field measures 208 x 208 arcsec2. The above collection of impressive VLT colour photos is unique. They show some of the highest excitation nebulae in the Magellanic Clouds (MCs), two satellite galaxies of our own Milky Way. They may be enjoyed for their beauty alone. However, each of them also carries a message about the depicted objects, their properties and evolutionary state. In fact, they represent the spectacular and visible result of a dedicated research programme begun by an international team of astronomers from Belgium and the United States of America [1], and aimed at unravelling the secrets of unsually hot nebulae. What makes them shine? From where come the enormous energies needed to make these nebulae glow in the light of ionized helium atoms? Emission nebulae Nebulae are huge clouds of gas and dust, the cosmic material from which stars and planets form, cf. the Appendix. Many of them emit their own light, and are then called emission nebulae. Astronomers distinguish between Planetary Nebulae (PNe), Supernova Remnants (SNRs) and "normal" emission nebulae or "HII regions" (pronounced "Eitch-two"). PNe result from the death of comparatively light stars, similar to our Sun, while SNRs originate from the explosive death of heavier stars. The collision between the surrounding interstellar matter and that ejected by the dying star, accompanied by the intense radiation from the hot stellar remnant (white dwarf, neutron star) excites the gas and makes it shine brightly. But the radiation of young hot stars embedded in an interstellar cloud is also able to heat the surrounding gas, resulting in the apparition of another type of emission nebula, that shines mostly in the light of ionized hydrogen (H) atoms. Such nebulae are therefore often referred to as "HII regions". The well-known Orion Nebula is an outstanding example of that type of nebula, cf. ESO PR Photos 03a-c/01. Highly excited nebulae The hotter the central object of an emission nebula, whether a white dwarf, a neutron star or just a young star, the hotter and more excited will be the surrounding nebula. The word "excitation" refers to the degree of ionization of the nebular gas. The more energetic the impinging particles and radiation, the more electrons will be lost and higher is the degree of excitation. Only in the most excited nebulae is there enough ultraviolet energy to completely ionize the helium atoms. When these ions subsequently capture an electron, this process gives rise to the characteristic radiation of single ionized helium (HeII). A particularly useful way to trace the very highest excitation areas is thus to map the distribution of HeII by means of imaging or spectroscopic observations that are sensitive to the radiation from these helium ions, for example at a particular wavelength in blue light (468.6 nm). It is common to detect the presence of HeII in Planetary Nebulae around extremely hot white dwarf stars, but not in "normal" HII regions. However, a few otherwise seemingly normal HII regions reveal the characteristics of high excitation. One of them is located in our own Milky Way galaxy, another has been found in the nearby galaxy IC 1613, and five others are situated in the Magellanic Clouds. Astronomers have also detected the presence of HeII ions in a number of remote galaxies undergoing a phase of intense star formation ("starburst galaxies") and in the vicinity of ultraluminous X-ray sources in very distant galaxies. What is going on in those remote objects in the early Universe? Do we see the action of young and very hot stars or is something unknown going on? What can the existence of those hot nebulae in young galaxies tell about the evolution of our own Milky Way? Searching for the energy source We would like to know, but those distant nebulae are unfortunately too faint to be studied in any reasonable detail, even by means of the largest available telescopes. The only way forward is therefore to look closer at the nearest ones in the hope that they will provide clues about the processes leading to the observed high excitation and thus help to better understand their cousins in those distant galaxies. There appears to be three possible answers to the basic question about the nature of the energetic sources that heat these strange emission nebulae: * very fast particles: if there is in the area a fast-moving gas (more than 100 km/s), the shock created by the impact of this material is able to heat the ambient interstellar medium sufficiently to produce a HeII nebula. * ultraviolet emission from massive stars: according to the most recent model calculations, even the most massive O-type stars do not emit enough ultraviolet light to ionize a sufficient number of helium atoms in the surrounding nebula to produce a detectable HeII nebula. However, some of the hottest stars of the so-called Wolf-Rayet (W-R) type (that are the evolved descendants of O-stars) may produce enough high energy emission to completely ionize the helium atoms in their surroundings. * intense X-ray emission: close binary stars in which one component is a "compact" object (a white dwarf, a neutron star, or a black hole) and the other an "ordinary" star can produce an intense X-ray emission. This happens because the compact object is so dense and massive that it siphons off matter from its companion star - astronomers refer to this as an accretion process, sometimes also called "stellar cannibalism". When the "stolen" matter approaches the compact object, it gradually heats up and may reach temperatures of millions of degrees. It then emits X-rays. At the same time, ultraviolet radiation is also emitted, which may produce high excitation regions in the surrounding nebula. This scenario can also explain the association of HeII nebulae with ultraluminous X-ray sources in other galaxies. VLT observations of highly excited nebulae in the MCs Observations of a number of highly excited nebulae in the Magellanic Clouds were carried out by a team composed of Belgian and American astronomers [1] in January 2002, by means of the FORS1 multi-mode instrument at the 8.2-m VLT MELIPAL telescope. Detailed images were obtained through various special optical filters - they bring into light the complex structure of these nebulae and reveal for the first time the exact morphology of the high excitation zones. Some of exposures have been combined to produce the colour photos shown in PR Photos 09a-d/03. Here, the blue colour traces the exceptional HeII emission, whilst the red and green correspond to the more common nebular emissions from atomic hydrogen and doubly-ionized oxygen, respectively. All four nebulae shown were found to be associated with very hot stars. They carry rather prosaic names: BAT99-2 and BAT99-49, AB7 and N44C Star #2 [2]. The first three of these objects contain some of the highly evolved massive stars, of the so-called Wolf-Rayet (WR) type, while the fourth is an mid-age massive star, of type O. Massive stars, with masses more than 20 times that of the Sun, are very bright (100,000 to 10 million times brighter than the Sun), very blue and very hot, with surface temperatures of a few tens of thousands of degrees. Another property of these exceptional stars is their very strong stellar winds: they continuously eject energetic particles - like the "solar wind" from the Sun - but some 10 to 1000 million times more intensely than our star! These powerful winds exert an enormous pressure on the surrounding interstellar material and forcefully shape those clouds into "bubbles". These photos have now provided the astronomers with sufficient information to understand exactly what is going on in three of those unusual nebulae - while one case still remains ambiguous. The nebulae around BAT99-2, BAT99-49 and AB7 BAT99-2 (cf. PR Photo 09b/03) is one of the hottest WR-stars known in the Large Magellanic Cloud (LMC). Before this star reached this phase of its short life, the strong stellar wind from its progenitor O-type star swept the interstellar medium and created a "bubble", much like a snowplough pushes aside the snow on a road. Part of this "bubble" can still be seen as a large half-ring to the south of the star. When the star did become a WR, the increasingly intense stellar wind impacted on the material previously ejected from the star. This created a new bubble, now visible as a small arc-like structure to the north-west of the star. We are appparently witnessing an ongoing merger of these two bubbles. With its strong ultraviolet (UV) radiation, BAT99-2 is strongly heating its immediate surroundings, in particular the above mentioned arc-like feature that, due to the resulting high excitation, is seen as a violet-pink region in the colour image. The entire field is very complex - the presence of a supernova remnant (SNR) is revealed by a few faint red filaments rather close to the high excitation nebula, to the north-west of the arc-like structure. AB7 (PR Photo 09a/03) and BAT99-49 (PR Photo 09c/03) are both binary stars, consisting of one WR-star and a companion O-type star. Like in the case of BAT99-2, the strong UV-radiation from their WR-star has created HeII nebulae around them, well visible in the photos by their blue colour. AB7 is particularly remarkable: the associated huge nebula and HeII region indicate that this star is one of the, if not THE, hottest WR-star known so far, with a surface temperature in excess of 120,000 degrees! Just outside this nebula, a small network of green filaments is visible - they are the remains of another supernova explosion. The new VLT images, complemented with VLT spectra, demonstrate that these stars are indeed the source of the observed ionization. These very first maps of the HeII emission unveil the as yet undiscovered complex structure of those highly excited nebulae. Moreover, the new observations provide the first accurate determination of the true ionizing power of these exceptional stars. They allow a direct measurement of the otherwise unobservable intensity of the far-UV emission of WR stars. The new observations have clearly identified the ultraviolet emission of very massive stars as the energy source in these three nebulae. Using the latest theoretical models to interpret these unique data, the Belgian astronomers and their American collaborator were also able to show that all of these stars are hotter than 90,000 degrees! The N44C nebula The fourth photo, PR Photo 09d/03, shows the very peculiar nebula N44C in the LMC. There is a beautiful (blue) HeII nebula near the two central stars. It is very different from the larger, "normal" HII region that is delimited by the light from atomic hydrogen (red) and doubly-ionized oxygen (green): this hot central region of N44C rather appears to "enshroud" the stars like a veil. There is a mystery, though. With a temperature of "only" a few tens of thousand degrees, even the hottest of the two stars, an O-type star (the upper one), cannot possibly be responsible for this inner high excitation nebula [3]. Moreover, no fast motions have so far been detected in the vicinity. Some astronomers have suggested that N44C is a "fossil X-ray nebula". What does that mean ? It may well be that this O-type star is not alone, but actually possesses a compact companion. The X-ray emission from such a binary may not be constant. During their orbital motion, the two stars can move away from each other, and the larger separation may cause the X-ray emission to stop (because of the cessation of accretion of matter onto the compact object). In this case, the observed high excitation nebula could still persist for a short period of time as a "fossil" of the previous X-ray ionized nebula. Later, that part of the nebula would then gradually disappear. However, to the astonishment of the astronomers, the present VLT observations show little or no variation in the HeII emission. Thus the above described "fossil X-ray nebula" explanation does not appear to be completely adequate and the cause of the high excitation in N44C remains a challenge to astronomers. "You can't win them all", says Yaël Nazé. "We were able to fully understand three nebulae, but we must now look more closely at N44C. I would not be surprised, if we will be able to solve this riddle by means of additional VLT observations." More information The information contained in this press release is based on two research articles to be published in the European research journal "Astronomy & Astrophysics", one of which is available at the preprint website at the Institut d'Astrophysique et de Géophysique de Liège (Belgium). Notes [1]: The team consists of Yaël Nazé, Grégor Rauw, Jean Manfroid and Jean-Marie Vreux (Liège Institute, Belgium), and You-Hua Chu (University of Illinois, USA). [2]: The names of these stars refer to the research papers in which they were first decribed. BAT99-2 and BAT99-49 are nos. 2 and 49 in the list published by Breysacher, Azzopardi and Testor (A&AS, 137, 117, 1999), AB7 is star no. 7 in the list by Azzopardi and Breysacher (A&A, 75, 120, 1979) and N44C Star #2 is included in a paper by Stasinska, Testor and Heydari-Malayeri (A&A, 170, L4, 1986). [3]: Consequently, contrary to what was possible in the other three nebulae, the observed extent of that nebula does not allow measuring the temperature of the hot O-type star. Contact Yaël Nazé Institut d'Astrophysique et de Géophysique Liège, Belgium Phone: +32 4 366 97 20 email: naze@astro.ulg.ac.be Appendix: Different types of nebulae   Nebulae are huge clouds of gas and dust, the cosmic material from which stars and planets form. Most of them belong to five main categories, each representing a different physical state. Two of these do not shine by their own light, but three others do. Dark nebulae and reflection nebulae If the gas does not emit visible light by itself, astronomers talk about dark nebulae or reflection nebulae. The former block the light from objects behind them, and they are therefore seen as dark regions in the sky - famous examples are the Barnard 68 "globule" (cf. ESO ESO PR 01/01 and ESO PR Photos 29a-c/99) and the "Horsehead Nebula" (ESO PR Photos 02a-b/02). Contrarily, reflection nebulae appear as bright areas in the sky because their dust particles reflect the light emitted by nearby stars. A good example is the nebulae surrounding some of the brightest stars in the "Pleiades" stellar cluster or in the southern Chamaeleon I area, cf. ESO PR Photo 17c/99. Emission nebulae Other nebulae emit visible light of their own. Astronomers distinguish between Planetary Nebulae (PNs), Supernova Remnants (SNRs) and "normal" emission nebulae or "HII regions" (pronounced "Eitch-two"). When stars die, they eject copious amounts of matter into neighbouring space. These ejecta collide with and heat the surrounding interstellar matter. This is sometimes accompanied by intense radiation from the hot stellar remnant at the centre. These processes excite the interstellar gas (and the ejecta) so that they shine brightly. In the case of lighter stars like the Sun, the remnant object is a hot "white dwarf", a star barely larger than the Earth and the surrounding nebula is called a "Planetary Nebula (PN)". This historical term refers to the planet-like appearance of such a nebula in a small telescope. A fine example is the "Dumbbell Nebula", photographed by the VLT in 1998, cf. ESO PR Photos 38a-b/98. On the other hand, heavier stars explode violently - such dramatic events are seen as supernovae - and leave behind a exceedingly hot and dense, rotating "neutron star" of diameter 10-20 km (or, in the case of the heaviest stars, presumably a "black hole") as well as a surrounding nebula, the supernova remnant (SNR). A famous example is the "Crab Nebula" from the supernova that exploded in the year 1054, cf. ESO PR Photos 40f-i/99. Finally, the radiation of young hot stars embedded in an interstellar cloud is also able to heat the surrounding gas, resulting in the apparition of an emission nebula, that shines mostly in the light of ionized hydrogen (H) atoms. Such nebulae are therefore often referred to as "HII regions". The well-known Orion Nebula is an outstanding example of that type of nebula, cf. ESO PR Photos 03a-c/01.

Physicochemical properties and ability to generate free radicals of ambient coarse, fine, and ultrafine particles in the atmosphere of Xuanwei, China, an area of high lung cancer incidence

NASA Astrophysics Data System (ADS)

Lu, Senlin; Yi, Fei; Hao, Xiaojie; Yu, Shang; Ren, Jingjing; Wu, Minghong; Jialiang, Feng; Yonemochi, Shinich; Wang, Qingyue

2014-11-01

The link between the high incidence of lung cancer and harmful pollutants emitted by local coal combustion in Xuanwei, Yunnan province, China, has been a focus of study since the 1980s. However, the mechanisms responsible for the high lung cancer rate remain unclear, necessitating further study. Since a close relationship between ambient air particle pollution and respiratory diseases exists, we sampled size-resolved ambient particles from the atmosphere of Xuanwei. In our indoor experiment, cutting-edge methods, including scanning electron microscopy coupled with energy dispersive X-ray detection (SEM/EDX), particle-induced X-ray emission (PIXE), electronic paramagnetic resonance (EPR) and the cell-free DCFH-DA assay, were employed to investigate the physicochemical properties, the potential to generate free radicals and the oxidative potential of ambient coarse (diameter, 1.8-10 μm), fine (diameter, 0.1-1.8 μm), and ultrafine (diameter, <0.1 μm) particles. We found the total mass concentrations of the size-resolved particles collected in spring were higher than that in early winter. Mass percentage of fine particles accounted for 68% and 61% of the total particulate mass in spring and in early winter samples, respectively, indicating that fine particles were the major component of the Xuanwei ambient particulate matters. On the other hand, the results of SEM/EDX analysis showed that the coarse particles were dominated by minerals, the fine particles by soot aggregates and fly ashes, and the ultrafine particles by soot particles and unidentified particles. Our PIXE results revealed that crustal elements (Ca, Ti Si, Fe) were mainly distributed in coarse particles, while trace metals (Cr, Mn, Ni, Cu, Zn, Pb) dominated in the fine particle fraction, and S, a typical element emitted by coal combustion, mainly resided in fine particles collected from the winter atmosphere. EPR results indicated that the magnitude of free radical intensity caused by size-resolved particles followed these patterns: fine particles > coarse particles > ultrafine particles for spring samples and ultrafine particles > fine particles > coarse particles for winter samples. Cell-free DCFH assay results conclusively showed that all of the measured particle suspensions displayed a higher oxidative potential than the negative control. The correlation coefficient (R2) between free radical intensity and fluorescent intensity generated by the size-resolved particles was 0.535 and 0.507 for the spring and winter seasons, respectively, implying that ambient air particles in the Xuanwei atmosphere have the ability to generate free radicals, and fine and ultrafine particles could be hazardous to local residents.

Ion Beam Facilities at the National Centre for Accelerator based Research using a 3 MV Pelletron Accelerator

NASA Astrophysics Data System (ADS)

Trivedi, T.; Patel, Shiv P.; Chandra, P.; Bajpai, P. K.

A 3.0 MV (Pelletron 9 SDH 4, NEC, USA) low energy ion accelerator has been recently installed as the National Centre for Accelerator based Research (NCAR) at the Department of Pure & Applied Physics, Guru Ghasidas Vishwavidyalaya, Bilaspur, India. The facility is aimed to carried out interdisciplinary researches using ion beams with high current TORVIS (for H, He ions) and SNICS (for heavy ions) ion sources. The facility includes two dedicated beam lines, one for ion beam analysis (IBA) and other for ion implantation/ irradiation corresponding to switching magnet at +20 and -10 degree, respectively. Ions with 60 kV energy are injected into the accelerator tank where after stripping positively charged ions are accelerated up to 29 MeV for Au. The installed ion beam analysis techniques include RBS, PIXE, ERDA and channelling.

Main atmospheric heavy metal sources in Portugal by biomonitor analysis

NASA Astrophysics Data System (ADS)

Reis, M. A.; Alves, L. C.; Wolterbeek, H. Th.; Verburg, T.; Freitas, M. C.; Gouveia, A.

1996-04-01

During the months of July and August of 1993 a lichen collection campaign was held in Portugal where about 250 samples were collected and analysed by thick target PIXE and INAA. Results for 43 different elements were obtained and a data base was built and subjected to Monte Carlo aided target transform factor analysis (MCATTFA), method developed at IRI TU Delft. 10 × 10 km coast and 50 × 50 km far from coast sampling grids were used for collection, concentration data as well as factor patterns were extrapolated to the whole country making use of an extinction rule of 1/r 3. In this work we present the results that were obtained based on a reduced data set of 22 elements measured by TTPIXE. The results for INAA data subset and the total data set are presented elsewhere.

First-Ever Census of Variable Mira-Type Stars in Galaxy Outside the Local Group

NASA Astrophysics Data System (ADS)

2003-05-01

First-Ever Census of Variable Mira-Type Stars in Galaxy Outsidethe Local Group Summary An international team led by ESO astronomer Marina Rejkuba [1] has discovered more than 1000 luminous red variable stars in the nearby elliptical galaxy Centaurus A (NGC 5128) . Brightness changes and periods of these stars were measured accurately and reveal that they are mostly cool long-period variable stars of the so-called "Mira-type" . The observed variability is caused by stellar pulsation. This is the first time a detailed census of variable stars has been accomplished for a galaxy outside the Local Group of Galaxies (of which the Milky Way galaxy in which we live is a member). It also opens an entirely new window towards the detailed study of stellar content and evolution of giant elliptical galaxies . These massive objects are presumed to play a major role in the gravitational assembly of galaxy clusters in the Universe (especially during the early phases). This unprecedented research project is based on near-infrared observations obtained over more than three years with the ISAAC multi-mode instrument at the 8.2-m VLT ANTU telescope at the ESO Paranal Observatory . PR Photo 14a/03 : Colour image of the peculiar galaxy Centaurus A . PR Photo 14b/03 : Location of the fields in Centaurus A, now studied. PR Photo 14c/03 : "Field 1" in Centaurus A (visual light; FORS1). PR Photo 14d/03 : "Field 2" in Centaurus A (visual light; FORS1). PR Photo 14e/03 : "Field 1" in Centaurus A (near-infrared; ISAAC). PR Photo 14f/03 : "Field 2" in Centaurus A (near-infrared; ISAAC). PR Photo 14g/03 : Light variation of six variable stars in Centaurus A PR Photo 14h/03 : Light variation of stars in Centaurus A (Animated GIF) PR Photo 14i/03 : Light curves of four variable stars in Centaurus A. Mira-type variable stars Among the stars that are visible in the sky to the unaided eye, roughly one out of three hundred (0.3%) displays brightness variations and is referred to by astronomers as a "variable star". The percentage is much higher among large, cool stars ("red giants") - in fact, almost all luminous stars of that type are variable. Such stars are known as Mira-variables ; the name comes from the most prominent member of this class, Omicron Ceti in the constellation Cetus (The Whale), also known as "Stella Mira" (The Wonderful Star). Its brightness changes with a period of 332 days and it is about 1500 times brighter at maximum (visible magnitude 2 and one of the fifty brightest stars in the sky) than at minimum (magnitude 10 and only visible in small telescopes) [2]. Stars like Omicron Ceti are nearing the end of their life. They are very large and have sizes from a few hundred to about a thousand times that of the Sun. The brightness variation is due to pulsations during which the star's temperature and size change dramatically. In the following evolutionary phase, Mira-variables will shed their outer layers into surrounding space and become visible as planetary nebulae with a hot and compact star (a "white dwarf") at the middle of a nebula of gas and dust (cf. the "Dumbbell Nebula" - ESO PR Photo 38a-b/98 ). Several thousand Mira-type stars are currently known in the Milky Way galaxy and a few hundred have been found in other nearby galaxies, including the Magellanic Clouds. The peculiar galaxy Centaurus A ESO PR Photo 14a/03 ESO PR Photo 14a/03 [Preview - JPEG: 400 x 451 pix - 53k [Normal - JPEG: 800 x 903 pix - 528k] [Hi-Res - JPEG: 3612 x 4075 pix - 8.4M] ESO PR Photo 14b/03 ESO PR Photo 14b/03 [Preview - JPEG: 570 x 400 pix - 52k [Normal - JPEG: 1140 x 800 pix - 392k] ESO PR Photo 14c/03 ESO PR Photo 14c/03 [Preview - JPEG: 400 x 451 pix - 61k [Normal - JPEG: 800 x 903 pix - 768k] ESO PR Photo 14d/03 ESO PR Photo 14d/03 [Preview - JPEG: 400 x 451 pix - 56k [Normal - JPEG: 800 x 903 pix - 760k] Captions : PR Photo 14a/03 is a colour composite photo of the peculiar galaxy Centaurus A (NGC 5128) , obtained with the Wide-Field Imager (WFI) camera at the ESO/MPG 2.2-m telescope on La Silla. It is based on a total of nine 3-min exposures made on March 25, 1999, through different broad-band optical filters (B(lue) - total exposure time 9 min - central wavelength 456 nm - here rendered as blue; V(isual) - 540 nm - 9 min - green; I(nfrared) - 784 nm - 9 min - red); it was prepared from files in the ESO Science Data Archive by ESO-astronomer Benoît Vandame . The elliptical shape and the central dust band, the imprint of a galaxy collision, are well visible. PR Photo 14b/03 identifies the two regions of Centaurus A (the rectangles in the upper left and lower right inserts) in which a search for variable stars was made during the present research project: "Field 1" is located in an area north-east of the center in which many young stars are present. This is also the direction in which an outflow ("jet") is seen on deep optical and radio images. "Field 2" is positioned in the galaxy's halo, south of the centre. High-resolution, very deep colour photos of these two fields and their immediate surroundings are shown in PR Photos 14c-d/03 . They were produced by means of CCD-frames obtained in July 1999 through U- and V-band optical filters with the VLT FORS1 multi-mode instrument at the 8.2-m VLT ANTU telescope on Paranal. Note the great variety of object types and colours, including many background galaxies which are seen through these less dense regions of Centaurus A . The total exposure time was 30 min in each filter and the seeing was excellent, 0.5 arcsec. The original pixel size is 0.196 arcsec and the fields measure 6.7 x 6.7 arcmin 2 (2048 x 2048 pix 2 ). North is up and East is left on all photos. Centaurus A (NGC 5128) is the nearest giant galaxy, at a distance of about 13 million light-years. It is located outside the Local Group of Galaxies to which our own galaxy, the Milky Way, and its satellite galaxies, the Magellanic Clouds, belong. Centaurus A is seen in the direction of the southern constellation Centaurus. It is of elliptical shape and is currently merging with a companion galaxy, making it one of the most spectacular objects in the sky, cf. PR Photo 14a/03 . It possesses a very heavy black hole at its centre (see ESO PR 04/01 ) and is a source of strong radio and X-ray emission. During the present research programme, two regions in Centaurus A were searched for stars of variable brightness; they are located in the periphery of this peculiar galaxy, cf. PR Photos 14b-d/03 . An outer field ("Field 1") coincides with a stellar shell with many blue and luminous stars produced by the on-going galaxy merger; it lies at a distance of 57,000 light-years from the centre. The inner field ("Field 2") is more crowded and is situated at a projected distance of about 30,000 light-years from the centre.. Three years of VLT observations ESO PR Photo 14e/03 ESO PR Photo 14e/03 [Preview - JPEG: 400 x 447 pix - 120k [Normal - JPEG: 800 x 894 pix - 992k] ESO PR Photo 14f/03 ESO PR Photo 14f/03 [Preview - JPEG: 400 x 450 pix - 96k [Normal - JPEG: 800 x 899 pix - 912k] Caption : PR Photos 14e-f/03 are colour composites of two small fields ("Field 1" and "Field 2") in the peculiar galaxy Centaurus A (NGC 5128) , based on exposures through three near-infrared filters (the J-, H- and K-bands at wavelengths 1.2, 1.6 and 2.2 µm, respectively) with the ISAAC multi-mode instrument at the 8.2-m VLT ANTU telescope at the ESO Paranal observatory. The corresponding areas are outlined within the two inserts in PR Photo 14b/03 and may be compared with the visual images from FORS1 ( PR Photos 14c-d/03 ). These ISAAC photos are the deepest near-infrared images ever obtained in this galaxy and show thousands of its stars of different colours. In the present colour-coding, the redder an image, the cooler is the star. The original pixel size is 0.15 arcsec and both fields measure 2.5 x 2.5 arcmin 2. North is up and East is left. Under normal circumstances, any team of professional astronomers will have access to the largest telescopes in the world for only a very limited number of consecutive nights each year. However, extensive searches for variable stars like the present require repeated observations lasting minutes-to-hours over periods of months-to-years. It is thus not feasible to perform such observations in the classical way in which the astronomers travel to the telescope each time. Fortunately, the operational system of the VLT at the ESO Paranal Observatory (Chile) is also geared to encompass this kind of long-term programme. Between April 1999 and July 2002, the 8.2-m VLT ANTU telescope on Cerro Paranal in Chile) was operated in service mode on many occasions to obtain K-band images of the two fields in Centaurus A by means of the near-infrared ISAAC multi-mode instrument. Each field was observed over 20 times in the course of this three-year period ; some of the images were obtained during exceptional seeing conditions of 0.30 arcsec. One set of complementary optical images was obtained with the FORS1 multi-mode instrument (also on VLT ANTU) in July 1999. Each image from the ISAAC instrument covers a sky field measuring 2.5 x 2.5 arcmin 2. The combined images, encompassing a total exposure of 20 hours are indeed the deepest infrared images ever made of the halo of any galaxy as distant as Centaurus A , about 13 million light-years. Discovering one thousand Mira variables ESO PR Photo 14g/03 ESO PR Photo 14g/03 [Preview - JPEG: 400 x 480 pix - 61k [Normal - JPEG: 800 x 961 pix - 808k] ESO PR Photo 14h/03 ESO PR Photo 14h/03 [Animated GIF: 263 x 267 pix - 56k ESO PR Photo 14i/03 ESO PR Photo 14i/03 [Preview - JPEG: 480 x 400 pix - 33k [Normal - JPEG: 959 x 800 pix - 152k] Captions : PR Photo 14g/03 shows a zoomed-in area within "Field 2" in Centaurus A , from the ISAAC colour image shown in PR Photo 14e/03 . Nearly all red stars in this area are of the variable Mira-type. The brightness variation of some stars (labelled A-D) is demonstrated in the animated-GIF image PR Photo 14h/03 . The corresponding light curves (brightness over the pulsation period) are shown in PR Photo 14i/03 . Here the abscissa indicates the pulsation phase (one full period corresponds to the interval from 0 to 1) and the ordinate unit is near-infrared K s -magnitude. One magnitude corresponds to a difference in brightness of a factor 2.5. Once the lengthy observations were completed, two further steps were needed to identify the variable stars in Centaurus A . First, each ISAAC frame was individually processed to identify the thousands and thousands of faint point-like images (stars) visible in these fields. Next, all images were compared using a special software package ("DAOPHOT") to measure the brightness of all these stars in the different frames, i.e., as a function of time. While most stars in these fields as expected were found to have constant brightness, more than 1000 stars displayed variations in brightness with time; this is by far the largest number of variable stars ever discovered in a galaxy outside the Local Group of Galaxies. The detailed analysis of this enormous dataset took more than a year. Most of the variable stars were found to be of the Mira-type and their light curves (brightness over the pulsation period) were measured, cf. PR Photo 14i/03 . For each of them, values of the characterising parameters, the period (days) and brightness amplitude (magnitudes) were determined. A catalogue of the newly discovered variable stars in Centaurus A has now been made available to the astronomical community via the European research journal Astronomy & Astrophysics. Marina Rejkuba is pleased and thankful: "We are really very fortunate to have carried out this ambitious project so successfully. It all depended critically on different factors: the repeated granting of crucial observing time by the ESO Observing Programmes Committee over different observing periods in the face of rigorous international competition, the stability and reliability of the telescope and the ISAAC instrument over a period of more than three years and, not least, the excellent quality of the service mode observations, so efficiently performed by the staff at the Paranal Observatory." What have we learned about Centaurus A? The present study of variable stars in this giant elliptical galaxy is the first-ever of its kind. Although the evaluation of the very large observational data material is still not finished, it has already led to a number of very useful scientific results. Confirmation of the presence of an intermediate-age population Based on earlier research (optical and near-IR colour-magnitude diagrams of the stars in the fields), the present team of astronomers had previously detected the presence of intermediate-age and young stellar populations in the halo of this galaxy. The youngest stars appear to be aligned with the powerful jet produced by the massive black hole at the centre. Some of the very luminous red variable stars now discovered confirm the presence of a population of intermediate-age stars in the halo of this galaxy. It also contributes to our understanding of how giant elliptical galaxies form. New measurement of the distance to Centaurus A The pulsation of Mira-type variable stars obeys a period-luminosity relation. The longer its period, the more luminous is a Mira-type star. This fact makes it possible to use Mira-type stars as "standard candles" (objects of known intrinsic luminosity) for distance determinations. They have in fact often been used in this way to measure accurate distances to more nearby objects, e.g., to individual clusters of stars and to the center in our Milky Way galaxy, and also to galaxies in the Local Group, in particular the Magellanic Clouds. This method works particularly well with infrared measurements and the astronomers were now able to measure the distance to Centaurus A in this new way. They found 13.7 ± 1.9 million light-years , in general agreement with and thus confirming other methods. Study of stellar population gradients in the halo of a giant elliptical galaxy The two fields here studied contain different populations of stars. A clear dependence on the location (a "gradient") within the galaxy is observed, which can be due to differences in chemical composition or age, or to a combination of both. Understanding the cause of this gradient will provide additional clues to how Centaurus A - and indeed all giant elliptical galaxies - was formed and has since evolved. Comparison with other well-known nearby galaxies Past searches have discovered Mira-type variable stars thoughout the Milky Way, our home galaxy, and in other nearby galaxies in the Local Group. However, there are no giant elliptical galaxies like Centaurus A in the Local Group and this is the first time it has been possible to identify this kind of stars in that type of galaxy. The present investigation now opens a new window towards studies of the stellar constituents of such galaxies .

Remote identification of individual volunteer cotton plants

USDA-ARS?s Scientific Manuscript database

Although airborne multispectral remote sensing can identify fields of small cotton plants, improvements to detection sensitivity are needed to identify individual or small clusters of plants that can similarly provide habitat for boll weevils. However, when consumer-grade cameras are used, each pix...

Assessing the accuracy and repeatability of automated photogrammetrically generated digital surface models from unmanned aerial system imagery

NASA Astrophysics Data System (ADS)

Chavis, Christopher

Using commercial digital cameras in conjunction with Unmanned Aerial Systems (UAS) to generate 3-D Digital Surface Models (DSMs) and orthomosaics is emerging as a cost-effective alternative to Light Detection and Ranging (LiDAR). Powerful software applications such as Pix4D and APS can automate the generation of DSM and orthomosaic products from a handful of inputs. However, the accuracy of these models is relatively untested. The objectives of this study were to generate multiple DSM and orthomosaic pairs of the same area using Pix4D and APS from flights of imagery collected with a lightweight UAS. The accuracy of each individual DSM was assessed in addition to the consistency of the method to model one location over a period of time. Finally, this study determined if the DSMs automatically generated using lightweight UAS and commercial digital cameras could be used for detecting changes in elevation and at what scale. Accuracy was determined by comparing DSMs to a series of reference points collected with survey grade GPS. Other GPS points were also used as control points to georeference the products within Pix4D and APS. The effectiveness of the products for change detection was assessed through image differencing and observance of artificially induced, known elevation changes. The vertical accuracy with the optimal data and model is ≈ 25 cm and the highest consistency over repeat flights is a standard deviation of ≈ 5 cm. Elevation change detection based on such UAS imagery and DSM models should be viable for detecting infrastructure change in urban or suburban environments with little dense canopy vegetation.

Research on Remote Sensing recognition features of Yuan Yang Terraces in Yunnan Province (China)

NASA Astrophysics Data System (ADS)

Xiang, Jie; Chen, Jianping; Lai, ZiLi; Yang, Wei

2016-04-01

Yuan Yang terraces is one of the most famous terraces in China, and it was successfully listed in the world heritage list at the 37th world heritage convention. On the one hand, Yuan Yang terraces retain more soil and water, to reduce both hydrological connectivity and erosion, and to support irrigation. On the other hand, It has the important tourism value, bring the huge revenue to local residents. In order to protect and make use of Yuan Yang terraces better, This study analyzed the spatial distribution and spectral characteristics of terraces:(1) Through visual interpretation, the study recognized the terraces based on the spatial adjusted remote sensing image (2010 Geoeye-1 with resolution of 1m/pix), and extracted topographic feature (elevation, slope, aspect, etc.) based on the digital elevation model with resolution of 20m/pix. The terraces cover a total area of about 11.58Km2, accounted for 24.4% of the whole study area. The terraces appear at range from 1400m to 1800m in elevation, 10°to 20°in slope, northwest to northeast in aspect; (2) Using the method of weight of evidence, this study assessed the importance of different topographic feature. The results show that the sort of importance: elevation>slope>aspect; (3) The study counted the Normalized Difference Vegetation Index (NDVI) changes of terraces throughout the year, based on the landsat-5 image with resolution of 30m/pix. The results show that the changes of terraces' NDVI are bigger than other stuff (e.g. forest, road, house, etc.). Those work made a good preparations for establishing the dynamic remote sensing monitoring system of Yuan Yang terraces.

A spray technique for preparing uniform large-area PIXE calibration standards from aqueous solutions

NASA Astrophysics Data System (ADS)

Menzel, N.; Hietel, B.; Leirer, M.; Szymczak, W.; Wittmaack, K.

1999-04-01

We describe a procedure for preparing reference standards that can be used to calibrate PIXE spectra of aerosol deposits collected on suitable backing films made, for example, of synthesised polymers (polypropylene, polycarbonate etc.) or chemically modified biopolymers (e.g., cellulose actetate). Aqueous solutions of well defined concentration were prepared from metal salts. The solutions were spray-deposited on cellulose acetate backings using a nebuliser. Lateral uniformity of the deposited layer over areas ranging from several mm to several cm was accomplished by raster scanning the table on which the backing was mounted. By optimising the experimental parameters, deposition could be accomplished without any detectable wetting of delicate substrates like paper. The areal density of the deposited material was calculated from the concentration of the solute, the volume of the consumed solution and the raster scanned area. The reference standards were analysed by PIXE using an external beam chamber backfilled with helium. The Si(Li) based detection system contained a thin funny filter so that X-ray spectra could be measured down to 1 keV. The proton energy on impact was 1.1 MeV. This relatively low probe energy has the advantage of producing favourable elemental X-ray peak heights relative to the bremsstrahlung-background, notably at energies between 2 and 7 keV. Under the same conditions sufficiently high X-ray yields were achieved for heavy elements like Zn and Pb. Using large area beams, bombardment-induced stress in the backing films could be kept at a low level so that very reproducible background spectra were obtained. Hence a straightforward background subtraction routine could be employed. Sensitivities were determined for 23 elements ranging from Na to Pb. Advantages and problems associated with the different metal salts are discussed briefly.

Nickel toxicity in the hepatopancreas of an isopod Porcellio scaber ( Oniscidea)

NASA Astrophysics Data System (ADS)

Tarnawska, M.; Migula, P.; Przybyłowicz, W.; Mesjasz-Przybyłowicz, J.; Augustyniak, M.

2007-07-01

This study is focused on recognizing how the functional role of hepatopancreas, the main metal storage organ in woodlice, is affected by the excess of nickel, a toxic element to soil invertebrates. Chronic Ni toxicity (24 weeks) was studied on four groups of woodlice kept on dry shredded maple leaves contaminated with Ni at average concentrations of 0.1 μg g -1 (control), 8.0 μg g -1 (Ni1), 75 μg g -1 (Ni2) and 270 μg g -1(Ni3) dry weight. Micro-PIXE mapping of elemental distribution in the hepatopancreas of the Porcellio scaber woodlice was used to study relations between nickel and other elements in individuals exposed to different metal concentrations in the diet. Data were processed using GeoPIXE II software. Transmission electron microscopy (TEM) was used to check the relations between ultrastructural changes in hepatopancreatic cells and nickel tissue burden. Elemental mapping showed a dose-related nickel bioaccumulation in the hepatopancreas at concentrations from 3 μg g -1 (uncontaminated control animals) to nearly 840 μg g -1 (Ni3). Generally, nickel was distributed uniformly in small aggregations. A combined evaluation of elemental maps and electronograms showed that aggregations of nickel in arbitrarily selected micro-areas in PIXE maps could be the granular structures observed in TEM electronograms. The mechanism of Ni sequestration in the hepatopancreas could be similar to this used for cadmium or lead. The sequences of ultrastructural changes, which follow the increased burdens of Ni in the hepatopancreatic cells, were: the increase of intracellular electron-dense granules, increase in the number of myelin-like structures, intensified mitochondrial swelling and appearance of concentrically arranged, rough endoplasmic reticulum.

VizieR Online Data Catalog: EBHIS spectra and HI column density maps (Winkel+, 2016)

NASA Astrophysics Data System (ADS)

Winkel, B.; Kerp, J.; Floeer, L.; Kalberla, P. M. W.; Ben Bekhti, N.; Keller, R.; Lenz, D.

2015-11-01

The EBHIS 1st data release comprises 21-cm neutral atomic hydrogen data of the Milky Way (-600km/s

Creating Slide Show Book Reports.

ERIC Educational Resources Information Center

Taylor, Harriet G.; Stuhlmann, Janice M.

1995-01-01

Describes the use of "Kid Pix 2" software by fourth grade students to develop slide-show book reports. Highlights include collaboration with education majors from Louisiana State University, changes in attitudes of the education major students and elementary students, and problems with navigation and disk space. (LRW)

Subcellular trace element distribution in Geosiphon pyriforme

NASA Astrophysics Data System (ADS)

Maetz, Mischa; Schüßler, Arthur; Wallianos, Alexandros; Traxel, Kurt

1999-04-01

Geosiphon pyriforme is a unique endosymbiotic consortium consisting of a soil dwelling fungus and the cyanobacterium Nostoc punctiforme. At present this symbiosis becomes very interesting because of its phylogenetic relationship to the arbuscular mycorrhizal (AM) fungi. Geosiphon pyriforme could be an important model system for these obligate symbiotic fungi, which supply 80-90% of all land plant species with nutrients, in particular phosphorous and trace elements. Combined PIXE and STIM analyses of the various compartments of Geosiphon give hints for the matter exchange between the symbiotic partners and their environment and the kind of nutrient storage and acquisition, in particular related to nitrogen fixation and metabolism. To determine the quality of our PIXE results we analysed several geological and biological standards over a time period of three years. This led to an overall precision of about 6% and an accuracy of 5-10% for nearly all detectable elements. In combination with the correction model for the occurring mass loss during the analyses this holds true even for biological targets.

Use of PIXE to measure serum copper, zinc, selenium, and bromine in patients with hematologic malignancies

NASA Astrophysics Data System (ADS)

Beguin, Y.; Bours, V.; Delbrouck, J.-M.; Robaye, G.; Roelandts, I.; Fillet, G.; Weber, G.

1990-04-01

The use of PIXE allowed for a simultaneous determination of serum copper (Cu), zinc (Zn), selenium (Se) and bromine (Br), in various groups of patients with hematologic malignancies. In 78 patients with acute nonlymphocytic leukemia, it was observed that (1) serum Se was significantly lower than in healthy controls and correlated inversely with the tumor burden; (2) serum bromine was normal at diagnosis but dropped dramatically after intensive chemotherapy, before recovering progressively over a period of months; and (3) pretreatment serum copper and zinc were significant prognostic factors of the chance to achieve a complete remission. In 50 patients with chronic lymphocytic leukemia, it was observed that (1) serum Cu and Cu/Zn ratio were useful indices of the disease activity, which were independent of a nonspecific acute phase reaction; and (2) Zn deficiency could contribute to immune dysfunction. In 119 patients with myeloproliferative disorders or myelodysplasic syndromes, serum Cu and Zn levels were mostly dependent on nonspecific factors, such as age and inflammation.

In vivo 3D PIXE-micron-CT imaging of Drosophila melanogaster using a contrast agent

NASA Astrophysics Data System (ADS)

Matsuyama, Shigeo; Hamada, Naoki; Ishii, Keizo; Nozawa, Yuichiro; Ohkura, Satoru; Terakawa, Atsuki; Hatori, Yoshinobu; Fujiki, Kota; Fujiwara, Mitsuhiro; Toyama, Sho

2015-04-01

In this study, we developed a three-dimensional (3D) computed tomography (CT) in vivo imaging system for imaging small insects with micrometer resolution. The 3D CT imaging system, referred to as 3D PIXE-micron-CT (PIXEμCT), uses characteristic X-rays produced by ion microbeam bombardment of a metal target. PIXEμCT was used to observe the body organs and internal structure of a living Drosophila melanogaster. Although the organs of the thorax were clearly imaged, the digestive organs in the abdominal cavity could not be clearly discerned initially, with the exception of the rectum and the Malpighian tubule. To enhance the abdominal images, a barium sulfate powder radiocontrast agent was added. For the first time, 3D images of the ventriculus of a living D. melanogaster were obtained. Our results showed that PIXEμCT can provide in vivo 3D-CT images that reflect correctly the structure of individual living organs, which is expected to be very useful in biological research.

Heaven and Earth - `Madonne col Bambino' and `Rustiques figulines'

NASA Astrophysics Data System (ADS)

Bouquillon, A.

Analyses of the productions of della Robbia and Palissy, two masters of Renaissance ceramics in France and in Italy, have enlightened their contributions to the improvement of the glazed terracotta technique. Della Robbia used very homogeneous materials: marly clay for the bodies, and tin-opacified coloured glazes. The technique is here very robust and very mastered. Palissy used different types of clay with different colours and physical properties, associated with specific productions. So far, we have identified seven pastes. Concerning the glazes, he played with transparency and opacity, with lead glazes and with tin-opacified lead glazes. He added traditional colouring oxides as well as specific pigments (lead-tin yellow, haematite, etc.). The mixed-earth technique is specific to his palette. So, the materials used by both artists are completely different and illustrate their different philosophical approaches. To perform the different analyses, new methodologies have been developed: ICP/AES-MS, petrography and X-ray diffractometry for the bodies, PIXE and micro-PIXE, SEM coupled with EDS and Raman spectrometry for the glazes.

P-cadherin promotes collective cell migration via a Cdc42-mediated increase in mechanical forces

PubMed Central

Plutoni, Cédric; Bazellieres, Elsa; Le Borgne-Rochet, Maïlys; Comunale, Franck; Brugues, Agusti; Séveno, Martial; Planchon, Damien; Thuault, Sylvie; Morin, Nathalie; Bodin, Stéphane; Trepat, Xavier

2016-01-01

Collective cell migration (CCM) is essential for organism development, wound healing, and metastatic transition, the primary cause of cancer-related death, and it involves cell–cell adhesion molecules of the cadherin family. Increased P-cadherin expression levels are correlated with tumor aggressiveness in carcinoma and aggressive sarcoma; however, how P-cadherin promotes tumor malignancy remains unknown. Here, using integrated cell biology and biophysical approaches, we determined that P-cadherin specifically induces polarization and CCM through an increase in the strength and anisotropy of mechanical forces. We show that this mechanical regulation is mediated by the P-cadherin/β-PIX/Cdc42 axis; P-cadherin specifically activates Cdc42 through β-PIX, which is specifically recruited at cell–cell contacts upon CCM. This mechanism of cell polarization and migration is absent in cells expressing E- or R-cadherin. Thus, we identify a specific role of P-cadherin through β-PIX–mediated Cdc42 activation in the regulation of cell polarity and force anisotropy that drives CCM. PMID:26783302

Depth profile by Total IBA in perovskite active layers for solar cells

NASA Astrophysics Data System (ADS)

Barreiros, M. A.; Alves, L. C.; Brites, M. J.; Corregidor, V.

2017-08-01

In recent years the record efficiency of perovskite solar cells (PSCs) has been updated exceeding now 20%. However, it is difficult to make PSCs consistently. Definite correlation has been established between the PSC performance and the perovskite film quality which involves mainly morphology, crystallinity and composition. The manufacturing development of these devices is dependent on the characterisation methodologies, on the availability of suitable and reliable analytical techniques to assess the materials composition and quality and on the relationship of these results with the cell performance. Ion beam analytical (IBA) techniques jointly with a micro-ion beam are powerful tools for materials characterisation and can provide a valuable input for the knowledge of perovskite films. Perovskite films based on CH3NH3PbI3 were prepared (from CH3NH3I and PbI2 precursors) in a planar architecture and in a mesoporous TiO2 scaffold. Proton and helium micro-beams at different energies were used in the analysis of PSC active layers, previously characterised by SEM-FEG (Scanning Electron Microscopy with a field emission gun) and XRD (X-ray diffraction). Self-consistent fit of all the obtained PIXE (Particle Induced X-ray Emission) and RBS (Rutherford Backscattering Spectrometry) spectra through Total IBA approach provided depth profiling of perovskite, its precursors and TiO2 and assess their distribution in the films. PbI2 presence and location on the active layer may hinder the charge transport and highly affect the cell performance. IBA techniques allowed to identify regions of non-uniform surface coverage and homogeneous areas and it was possible to establish the undesired presence of PbI2 and its quantitative depth profile in the planar architecture film. In the mesostructured perovskite film it was verified a non-homogeneous distribution with a decreasing of perovskite concentration down to the thin blocking layer. The good agreement between the best fits obtained in a Total IBA approach and the experimental data granted reliability to depth profile results for the studied perovskite films.

An Investigation of Size-Dependent Concentration of Trace Elements in Aerosols Emitted from the Oil-Fired Heating Plants

NASA Technical Reports Server (NTRS)

Singh, J. J.; Sentell, R. J.; Khandelwal, G. S.

1976-01-01

Aerosols emitted from two oil-fired heating plants were aerodynamically separated into eight size groups and were analyzed using the photon-induced X-ray emission (PIXE) technique. It was found that Zn, Mo, Ag, and Pb, and (to a lesser extent) Cd, have a tendency to concentrate preferentially on the smaller aerosols. All of these elements, in certain chemical forms, are known to be toxic. Zinc and molybdenum, although present in low concentrations in the parent fuels, show the strongest tendencies to be concentrated in finer aerosols. Selenium, previously reported to show a very strong tendency to concentration in finer fly ash from coal-fired power plants shows little preference for surface residence. Vanadium, which occurs in significant concentration in the oil fuels for both plants, also shows little preference for surface concentration. Even though the absolute concentrations of the toxic elements involved are well below the safety levels established by the National Institute for Occupational Safety and Health (NIOSH), it would be advisable to raise the heights of the heating-plant exhaust chimneys well above the neighborhood buildings to insure more efficient aerosol dispersal.

Uptake, localization, and speciation of cobalt in Triticum aestivum L. (wheat) and Lycopersicon esculentum M. (tomato).

PubMed

Collins, Richard N; Bakkaus, Estelle; Carrière, Marie; Khodja, Hicham; Proux, Olivier; Morel, Jean-Louis; Gouget, Barbara

2010-04-15

The root-to-shoot transfer, localization, and chemical speciation of Co were investigated in a monocotyledon (Triticum aestivum L., wheat) and a dicotyledon (Lycopersicon esculentum M., tomato) plant species grown in nutrient solution at low (5 muM) and high (20 muM) Co(II) concentrations. Cobalt was measured in the roots and shoots by inductively coupled plasma-mass spectrometry. X-ray absorption spectroscopy measurements were used to identify the chemical structure of Co within the plants and Co distribution in the leaves was determined by micro-PIXE (particle induced X-ray emission). Although the root-to-shoot transport was higher for tomato plants exposed to excess Co, both plants appeared as excluders. The oxidation state of Co(II) was not transformed by either plant in the roots or shoots and Co appeared to be present as Co(II) in a complex with carboxylate containing organic acids. Cobalt was also essentially located in the vascular system of both plant species indicating that neither responded to Co toxicity via sequestration in epidermal or trichome tissues as has been observed for other metals in metal hyperaccumulating plants.

Characterization of compositional modifications in metal-organic frameworks using carbon and alpha particle microbeams

NASA Astrophysics Data System (ADS)

Paneta, V.; Fluch, U.; Petersson, P.; Ott, S.; Primetzhofer, D.

2017-08-01

Zirconium-oxide based metal-organic frameworks (MOFs) were grown on p-type Si wafers. A modified linker molecule containing iodine was introduced by post synthetic exchange (PSE). Samples have been studied using Rutherford Backscattering Spectrometry (RBS) and Particle Induced X-ray Emission (PIXE) techniques, employing the 5 MV 15SDH-2 Pelletron Tandem accelerator at the Ångström laboratory. The degree of post synthetic uptake of the iodine-containing linker has been investigated with both a broad beam and a focused beam of carbon and alpha particles targeting different kind of MOF crystals which were of ∼1-10 μm in size, depending on the linker used. Iodine concentrations in MOF crystallites were also measured by Nuclear Magnetic Resonance Spectroscopy (NMR) and are compared to the RBS results. In parallel to the ion beam studies, samples were investigated by Scanning Electron Microscopy (SEM) to quantify possible crystallite clustering, develop optimum sample preparation routines and to characterize the potential ion beam induced sample damage and its dependence on different parameters. Based on these results the reliability and accuracy of ion beam data is assessed.

Biomass burning contributions estimated by synergistic coupling of daily and hourly aerosol composition records.

PubMed

Nava, S; Lucarelli, F; Amato, F; Becagli, S; Calzolai, G; Chiari, M; Giannoni, M; Traversi, R; Udisti, R

2015-04-01

Biomass burning (BB) is a significant source of particulate matter (PM) in many parts of the world. Whereas numerous studies demonstrate the relevance of BB emissions in central and northern Europe, the quantification of this source has been assessed only in few cities in southern European countries. In this work, the application of Positive Matrix Factorisation (PMF) allowed a clear identification and quantification of an unexpected very high biomass burning contribution in Tuscany (central Italy), in the most polluted site of the PATOS project. In this urban background site, BB accounted for 37% of the mass of PM10 (particulate matter with aerodynamic diameter<10 μm) as annual average, and more than 50% during winter, being the main cause of all the PM10 limit exceedances. Due to the chemical complexity of BB emissions, an accurate assessment of this source contribution is not always easily achievable using just a single tracer. The present work takes advantage of the combination of a long-term daily data-set, characterized by an extended chemical speciation, with a short-term high time resolution (1-hour) and size-segregated data-set, obtained by PIXE analyses of streaker samples. The hourly time pattern of the BB source, characterised by a periodic behaviour with peaks starting at about 6 p.m. and lasting all the evening-night, and its strong seasonality, with higher values in the winter period, clearly confirmed the hypothesis of a domestic heating source (also excluding important contributions from wildfires and agricultural wastes burning). Copyright © 2014 Elsevier B.V. All rights reserved.

Charting the Giants

NASA Astrophysics Data System (ADS)

2004-06-01

Largest Census Of X-Ray Galaxy Clusters Provides New Constraints on Dark Matter [1] Clusters of galaxies Clusters of galaxies are very large building blocks of the Universe. These gigantic structures contain hundreds to thousands of galaxies and, less visible but equally interesting, an additional amount of "dark matter" whose origin still defies the astronomers, with a total mass of thousands of millions of millions times the mass of our Sun. The comparatively nearby Coma cluster, for example, contains thousands of galaxies and measures more than 20 million light-years across. Another well-known example is the Virgo cluster at a distance of about 50 million light-years, and still stretching over an angle of more than 10 degrees in the sky! Clusters of galaxies form in the densest regions of the Universe. As such, they perfectly trace the backbone of the large-scale structures in the Universe, in the same way that lighthouses trace a coastline. Studies of clusters of galaxies therefore tell us about the structure of the enormous space in which we live. The REFLEX survey ESO PR Photo 18a/04 ESO PR Photo 18a/04 Galaxy Cluster RXCJ 1206.2-0848 (Visible and X-ray) [Preview - JPEG: 400 x 478 pix - 70k] [Normal - JPEG: 800 x 956 pix - 1.2Mk] Caption: PR Photo 18a shows the very massive distant cluster of galaxies RXCJ1206.2-0848, newly discovered during the REFLEX project, and located at a redshift of z = 0.44 [3]. The contours indicate the X-ray surface brightness distribution. Most of the yellowish galaxies are cluster members. A gravitationally lensed galaxy with a distorted, very elongated image is seen, just right of the centre. The image was obtained with the EFOSC multi-mode instrument on the ESO 3.6-m telescope at the La Silla Observatory (Chile). ESO PR Photo 18b/04 ESO PR Photo 18b/04 Galaxy cluster RXCJ1131.9-1955 [Preview - JPEG: 400 x 477 pix - 40k] [Normal - JPEG: 800 x 953 pix - 912k] [FullRes - JPEG: 2251 x 2681 pix - 7.7Mk] Caption: PR Photo 18b displays the very massive galaxy cluster RXCJ1131.9-1955 at redshift z = 0.306 [3] in a very rich galaxy field with two major concentrations. It was originally found by George Abell and designated "Abell 1300". The image was obtained with the ESO/MPG 2.2-m telescope and the WFI camera at La Silla. ESO PR Photo 18c/04 ESO PR Photo 18c/04 Galaxy Cluster RXCJ0937.9-2020 [Preview - JPEG: 400 x 746 pix - 60k] [Normal - JPEG: 800 x 1491 pix - 1.3M] [HiRes - JPEG: 2380 x 4437 pix - 14.2M] Caption: PR Photo 18c/04 shows the much smaller, more nearby galaxy group RXCJ0937.9-2020 at a redshift of z = 0.034 [3]. It is dominated by the massive elliptical galaxy seen at the top of the image. The photo covers only the southern part of this group. Such galaxy groups with typical masses of a few 1013 solar masses constitute the smallest objects included in the REFLEX catalogue. This image was obtained with the FORS1 multi-mode instrument on the ESO 8.2-m VLT Antu telescope. ESO PR Video Clip 05/04 ESO PR Video Clip 05/04 Galaxy Clusters in the REFLEX Catalogue (3D-visualization) [MPG - 11.7Mb] Caption: ESO PR Video Clip 05/04 illustrates the three-dimensional distribution of the galaxy clusters identfied in the ROSAT All-Sky survey in the northern and southern sky. In addition to the galaxy clusters in the REFLEX catalogue this movie also contains those identified during the ongoing, deeper search for X-ray clusters: the extension of the southern REFLEX Survey and the northern complementary survey that is conducted by the MPE team at the Calar Alto observatory and at US observatories in collaboration with John Huchra and coworkers at the Harvard-Smithonian Center for Astrophysics. In total, more than 1400 X-ray bright galaxy cluster have been found to date. (Prepared by Ferdinand Jamitzky.) Following this idea, a European team of astronomers [2], under the leadership of Hans Böhringer (MPE, Garching, Germany), Luigi Guzzo (INAF, Milano, Italy), Chris A. Collins (JMU, Liverpool), and Peter Schuecker (MPE, Garching) has embarked on a decade-long study of these gargantuan structures, trying to locate the most massive of clusters of galaxies. Since about one-fifth of the optically invisible mass of a cluster is in the form of a diffuse very hot gas with a temperature of the order of several tens of millions of degrees, clusters of galaxies produce powerful X-ray emission. They are therefore best discovered by means of X-ray satellites. For this fundamental study, the astronomers thus started by selecting candidate objects using data from the X-ray Sky Atlas compiled by the German ROSAT satellite survey mission. This was the beginning only - then followed a lot of tedious work: making the final identification of these objects in visible light and measuring the distance (i.e., redshift [3]) of the cluster candidates. The determination of the redshift was done by means of observations with several telescopes at the ESO La Silla Observatory in Chile, from 1992 to 1999. The brighter objects were observed with the ESO 1.5-m and the ESO/MPG 2.2-m telescopes, while for the more distant and fainter objects, the ESO 3.6-m telescope was used. Carried out at these telescopes, the 12 year-long programme is known to astronomers as the REFLEX (ROSAT-ESO Flux Limited X-ray) Cluster Survey. It has now been concluded with the publication of a unique catalogue with the characteristics of the 447 brightest X-ray clusters of galaxies in the southern sky. Among these, more than half the clusters were discovered during this survey. Constraining the dark matter content ESO PR Photo 18d/04 ESO PR Photo 18d/04 Constraints on Cosmological Parameters [Preview - JPEG: 400 pix x 572 - 37k] [Normal - JPEG: 800 x 1143 pix - 265k] Caption: PR Photo 18d demonstrates the current observational constraints on the cosmic density of all matter including dark matter (Ωm) and the dark energy (ΩΛ) relative to the density of a critical-density Universe (i.e., an expanding Universe which approaches zero expansion asymptotically after an infinite time and has a flat geometry). All three observational tests by means of supernovae (green), the cosmic microwave background (blue) and galaxy clusters converge at a Universe around Ωm ~ 0.3 and ΩΛ ~ 0.7. The dark red region for the galaxy cluster determination corresponds to 95% certainty (2-sigma statistical deviation) when assuming good knowledge of all other cosmological parameters, and the light red region assumes a minimum knowledge. For the supernovae and WMAP results, the inner and outer regions corespond to 68% (1-sigma) and 95% certainty, respectively. References: Schuecker et al. 2003, A&A, 398, 867 (REFLEX); Tonry et al. 2003, ApJ, 594, 1 (supernovae); Riess et al. 2004, ApJ, 607, 665 (supernovae) Galaxy clusters are far from being evenly distributed in the Universe. Instead, they tend to conglomerate into even larger structures, "super-clusters". Thus, from stars which gather in galaxies, galaxies which congregate in clusters and clusters tying together in super-clusters, the Universe shows structuring on all scales, from the smallest to the largest ones. This is a relict of the very early (formation) epoch of the Universe, the so-called "inflationary" period. At that time, only a minuscule fraction of one second after the Big Bang, the tiny density fluctuations were amplified and over the eons, they gave birth to the much larger structures. Because of the link between the first fluctuations and the giant structures now observed, the unique REFLEX catalogue - the largest of its kind - allows astronomers to put considerable constraints on the content of the Universe, and in particular on the amount of dark matter that is believed to pervade it. Rather interestingly, these constraints are totally independent from all other methods so far used to assert the existence of dark matter, such as the study of very distant supernovae (see e.g. ESO PR 21/98) or the analysis of the Cosmic Microwave background (e.g. the WMAP satellite). In fact, the new REFLEX study is very complementary to the above-mentioned methods. The REFLEX team concludes that the mean density of the Universe is in the range 0.27 to 0.43 times the "critical density", providing the strongest constraint on this value up to now. When combined with the latest supernovae study, the REFLEX result implies that, whatever the nature of the dark energy is, it closely mimics a Universe with Einstein's cosmological constant. A giant puzzle The REFLEX catalogue will also serve many other useful purposes. With it, astronomers will be able to better understand the detailed processes that contribute to the heating of the gas in these clusters. It will also be possible to study the effect of the environment of the cluster on each individual galaxy. Moreover, the catalogue is a good starting point to look for giant gravitational lenses, in which a cluster acts as a giant magnifying lens, effectively allowing observations of the faintest and remotest objects that would otherwise escape detection with present-day telescopes. But, as Hans Böhringer says: "Perhaps the most important advantage of this catalogue is that the properties of each single cluster can be compared to the entire sample. This is the main goal of surveys: assembling the pieces of a gigantic puzzle to build the grander view, where every single piece then gains a new, more comprehensive meaning." More information The results presented in this Press Release will appear in the research journal Astronomy and Astrophysics ("The ROSAT-ESO Flux Limited X-ray (REFLEX) Galaxy Cluster Survey. V. The cluster catalogue" by H. Böhringer et al.; astro-ph/0405546). See also the REFLEX website.

Evaluation of the effect of an environmental management program on exposure to manganese in a mining zone in Mexico.

PubMed

Cortez-Lugo, Marlene; Riojas-Rodríguez, Horacio; Moreno-Macías, Hortensia; Montes, Sergio; Rodríguez-Agudelo, Yaneth; Hernández-Bonilla, David; Catalán-Vázquez, Minerva; Díaz-Godoy, Raúl; Rodríguez-Dozal, Sandra

2018-01-01

In the state of Hidalgo, Mexico, is found the largest second deposit of Manganese (Mn) in Latin America. Various studies on the sources of emission, exposure, and the effects on the health of children and adults have been conducted utilizing an ecosystem approach. Given the findings of Mn levels in air and the neurocognitive effects, an Environmental Management Program (EMP) was designed and implemented with the purpose of reducing exposure to Mn of the population, including various actions for reducing Mn emissions into the atmosphere. To evaluate the impact of the EMP on the concentrations of Mn in air, as well as the modification of exposure to Mn in the blood and hair of adult residents of the communities intervened. A quasi-experimental study was conducted in five rural communities, in which Mn concentrations were evaluated in air and in blood in the years 2002 and 2007, pre-intervention, and in 2013, postintervention. In 2003, the concentration of hair Mn among the communities was evaluated. Measurements were carried out of Particulate Matter (PM) of >10 and 2.5μm (PM10 and PM2.5), and Mn in PM10 and PM2.5 were measured using proton-induced X-ray emissions (PIXE). The method of Difference in Differences (DID) was applied to estimate the impact of EMP on Mn concentrations in particulate matter via linear regression through multilevel models. To evaluate the effect of Mn concentrations in air over Mn concentrations in blood in both study periods in the mining communities per year (2002 and 2013), a linear regression model for each year was employed. We estimated that the EMP contributed to reducing the average daily concentrations of Mn in PM10 and PM2.5 by 92 and 85%, respectively. The adjusted model did not show an effect of Mn concentrations in air over Mn concentrations in blood in both study periods. The results suggest that the measures implemented to reduce Mn emissions in air exerted a significant impact on the reduction of inhaled exposure in adult population. Copyright © 2017 Elsevier B.V. All rights reserved.

How C2 Goes Wrong (Briefing Chart)

DTIC Science & Technology

2014-06-01

Guardian/Pix/pictures/2012/12/19/1355903591995/Hillsborough-disaster-010.jpg Cases (3): Disaster/Emergency Response (Cont.) Columbine High School ...r337173_1529332.jpg http://bossip.files.wordpress.com/2012/11/ massacre -e1352384704110.jpeg?w=625&h=389 The Punchline “What we’ve got here, is

Black Hole in Search of a Home

NASA Astrophysics Data System (ADS)

2005-09-01

Astronomers Discover Bright Quasar Without Massive Host Galaxy An international team of astronomers [1] used two of the most powerful astronomical facilities available, the ESO Very Large Telescope (VLT) at Cerro Paranal and the Hubble Space Telescope (HST), to conduct a detailed study of 20 low redshift quasars. For 19 of them, they found, as expected, that these super massive black holes are surrounded by a host galaxy. But when they studied the bright quasar HE0450-2958, located some 5 billion light-years away, they couldn't find evidence for an encircling galaxy. This, the astronomers suggest, may indicate a rare case of collision between a seemingly normal spiral galaxy and a much more exotic object harbouring a very massive black hole. With masses up to hundreds of millions that of the Sun, "super massive" black holes are the most tantalizing objects known. Hiding in the centre of most large galaxies, including our own Milky Way (see ESO PR 26/03), they sometimes manifest themselves by devouring matter they engulf from their surroundings. Shining up to the largest distances, they are then called "quasars" or "QSOs" (for "quasi-stellar objects"), as they had initially been confused with stars. Decades of observations of quasars have suggested that they are always associated with massive host galaxies. However, observing the host galaxy of a quasar is a challenging work, because the quasar is radiating so energetically that its host galaxy is hard to detect in the flare. ESO PR Photo 28a/05 ESO PR Photo 28a/05 Two Quasars with their Host Galaxy [Preview - JPEG: 400 x 760 pix - 82k] [Normal - JPEG: 800 x 1520 pix - 395k] [Full Res - JPEG: 1722 x 3271 pix - 4.0M] Caption: ESO PR Photo 28a/05 shows two examples of quasars from the sample studied by the astronomers, where the host galaxy is obvious. In each case, the quasar is the bright central spot. The host of HE1239-2426 (left), a z=0.082 quasar, displays large spiral arms, while the host of HE1503+0228 (right), having a redshift of 0.135, is more fuzzy and shows only hints of spiral arms. Although these particular objects are rather close to us and constitute therefore easy targets, their host would still be perfectly visible at much higher redshift, including at distances as large as the one of HE0450-2958 (z=0.285). The observations were done with the ACS camera on the HST. ESO PR Photo 28b/05 ESO PR Photo 28b/05 The Quasar without a Home: HE0450-2958 [Preview - JPEG: 400 x 760 pix - 53k] [Normal - JPEG: 800 x 1520 pix - 197k] [Full Res - JPEG: 1718 x 3265 pix - 1.5M] Caption of ESO PR Photo 28b/05: (Left) HST image of the z=0.285 quasar HE0450-2958. No obvious host galaxy centred on the quasar is seen. Only a strongly disturbed and star forming companion galaxy is seen near the top of the image. (Right) Same image shown after applying an efficient image sharpening method known as MCS-deconvolution. In contrast to the usual cases, as the ones shown in ESO PR Photo 28a/05, the quasar is not situated at the centre of an extended host galaxy, but on the edge of a compact structure, whose spectra (see ESO PR Photo 28c/05) show it to be composed of gas ionised by the quasar radiation. This gas may have been captured through a collision with the star-forming galaxy. The star indicated on the figure is a nearby galactic star seen by chance in the field of view. To overcome this problem, the astronomers devised a new and highly efficient strategy. Using ESO's VLT for spectroscopy and HST for imagery, they observed their quasars at the same time as a reference star. Simultaneous observation of a star allowed them to measure at best the shape of the quasar point source on spectra and images, and further to separate the quasar light from the other contribution, i.e. from the underlying galaxy itself. This very powerful image and spectra sharpening method ("MCS deconvolution") was applied to these data in order to detect the finest details of the host galaxy (see e.g. ESO PR 19/03). Using this efficient technique, the astronomers could detect a host galaxy for all but one of the quasars they studied. No stellar environment was found for HE0450-2958, suggesting that if any host galaxy exists, it must either have a luminosity at least six times fainter than expected a priori from the quasar observed luminosity, or a radius smaller than about 300 light-years. Typical radii for quasar host galaxies range between 6,000 and 50,000 light-years, i.e. they are at least 20 to 170 times larger. "With the data we managed to secure with the VLT and the HST, we would have been able to detect a normal host galaxy", says Pierre Magain (Université de Liège, Belgium), lead author of the paper reporting the study. "We must therefore conclude that, contrary to our expectations, this bright quasar is not surrounded by a massive galaxy." Instead, the astronomers detected just besides the quasar a bright cloud of about 2,500 light-years in size, which they baptized "the blob". The VLT observations show this cloud to be composed only of gas ionised by the intense radiation coming from the quasar. It is probably the gas of this cloud which is feeding the supermassive black hole, allowing it to become a quasar. ESO PR Photo 28c/05 ESO PR Photo 28c/05 Spectrum of Quasar HE0450-2958, the Blob and the Companion Galaxy (FORS/VLT) [Preview - JPEG: 400 x 561 pix - 112k] [Normal - JPEG: 800 x 1121 pix - 257k] [HiRes - JPEG: 2332 x 3268 pix - 1.1M] Caption: ESO PR Photo 28c/05 presents the spectra of the three objects indicated in ESO PR Photo 28b/05 as obtained with FORS1 on ESO's Very Large Telescope. The spectrum of the companion galaxy shown on the top panel reveals strong star formation. Thanks to the image sharpening process, it has been possible to separate very well the spectra of the quasar (centre) from that of the blob (bottom). The spectrum of the blob shows exclusively strong narrow emission lines having properties indicative of ionisation by the quasar light. There is no trace of stellar light, down to very faint levels, in the surrounding of the quasar. A strongly perturbed galaxy, showing all signs of a recent collision, is also seen on the HST images 2 arcseconds away (corresponding to about 50,000 light-years), with the VLT spectra showing it to be presently in a state where it forms stars at a frantic rate. "The absence of a massive host galaxy, combined with the existence of the blob and the star-forming galaxy, lead us to believe that we have uncovered a really exotic quasar, says team member Frédéric Courbin (Ecole Polytechnique Fédérale de Lausanne, Switzerland). "There is little doubt that a burst in the formation of stars in the companion galaxy and the quasar itself have been ignited by a collision that must haven taken place about 100 million years ago. What happened to the putative quasar host remains unknown." HE0450-2958 constitutes a challenging case of interpretation. The astronomers propose several possible explanations, that will need to be further investigated and confronted. Has the host galaxy been completely disrupted as a result of the collision? It is hard to imagine how that could happen. Has an isolated black hole captured gas while crossing the disc of a spiral galaxy? This would require very special conditions and would probably not have caused such a tremendous perturbation as is observed in the neighbouring galaxy. Another intriguing hypothesis is that the galaxy harbouring the black hole was almost exclusively made of dark matter. "Whatever the solution of this riddle, the strong observable fact is that the quasar host galaxy, if any, is much too faint", says team member Knud Jahnke (Astrophysikalisches Institut Potsdam, Germany). The report on HE0450-2958 is published in the September 15, 2005 issue of the journal Nature ("Discovery of a bright quasar without a massive host galaxy" by Pierre Magain et al.).

Quantitative mapping of elemental distribution in leaves of the metallophytes Helichrysum candolleanum, Blepharis aspera, and Blepharis diversispina from Selkirk Cu-Ni mine, Botswana

NASA Astrophysics Data System (ADS)

Koosaletse-Mswela, Pulane; Przybyłowicz, Wojciech J.; Cloete, Karen J.; Barnabas, Alban D.; Torto, Nelson; Mesjasz-Przybyłowicz, Jolanta

2015-11-01

Multi-element profiling is essential in understanding the metal-tolerant behavior of metallophytes. Although previous reports using multi-elemental analyses show that the metallophytes Blepharis aspera, Blepharis diversispina (Acanthaceae) and Helichrysum candolleanum (Asteraceae) take up metals, no information exists on elemental spatial distribution and concentrations in specific tissues of these plants. The aim of this study therefore was to assess the spatial distribution and concentration of copper, nickel and other elements in leaf tissues of these plants using micro-PIXE. Whole plants were collected with soil in pots from an operational copper and nickel mine (i.e., a copper and nickel mineralized area), Selkirk, about 40 km north-east of Francistown, Botswana. On the same day the samples were transported by air to iThemba LABS in South Africa. Leaf specimens were cryofixed in liquid propane cooled by LN2. Parallel samples were embedded in resin for anatomical studies to facilitate interpretation of elemental maps. The distribution and concentration of copper, nickel, and other elements in leaf tissues were determined using micro-PIXE and proton backscattering spectrometry. Data evaluation was performed using GeoPIXE II software. Micro-PIXE showed that H. candolleanum had the highest whole leaf content of copper (70 ± 3 μg g-1 DW) and nickel (168 ± 5 μg g-1 DW), followed by B. aspera (Cu: 25 ± 1 μg g-1 DW; Ni: 166 ± 4 μg g-1 DW) and B. diversispina (Cu: 3 ± 1 μg g-1 DW; Ni, below detection limit). For specific leaf tissues, the highest levels of copper were found in the vascular bundle for H. candolleanum (167 ± 7 μg g-1 DW) and the lower epidermis for B. aspera (70 ± 9 μg g-1 DW). The highest levels of nickel were present in the vascular bundle of B. aspera (479 ± 10 μg g-1 DW) and H. candolleanum (90 ± 5 μg g-1 DW). Elemental maps showed a similar distribution pattern for copper and nickel in B. aspera and B diversispina, with these elements concentrated in the upper and lower epidermal regions. However, for H. candolleanum, both copper and nickel were concentrated in the mesophyll. The difference in concentration and accumulation patterns between B. aspera, B. diversispina and H. candolleanum suggests that the metal-tolerant adaptation of these metallophytes may differ.

Surface protection coating material for controlling the decay of major construction stone

NASA Astrophysics Data System (ADS)

Arun, T.; Ray, D. K.; Gupta, V. P.; Panda, S. S.; Sahoo, P. K.; Ghosh, Jaydip; Sengupta, Pranesh; Satyam, P. V.

2017-05-01

Degradation of the building stones are creating instability in the old building and monuments which is to be protected. To investigate the characteristics of such a stones used for the construction in eastern India, we have collected the khondalite stones. The microstructural and elemental composition analysis of the khondalite stones are analyzed by using SEM, EDX and PIXE trace elemental analysis. We have prepared surface protection coating material with graphene oxide and cobalt ferrite as a base material along with other residuals. The prepared coating materials is coated on the galvanized iron substrate for further characterization. The surface morphology characteristics of the coating material is analyzed by SEM and AFM. The corrosion resistance characteristics of the prepared coating material is studied by the electrochemical impedance spectroscopy. The results suggests that the prepared coating material can be used as a surface protection materials to control the self-destruction of khondalite stones.

IBA analysis of some precolumbian gilded-copper samples

NASA Astrophysics Data System (ADS)

Andrade, E.; Murillo, G.; Policroniades, R.; Acosta, L.; Zavala, E. P.; Rocha, M. F.; Centeno, S. A.

2005-10-01

The elemental composition and depth profiles obtained by IBA techniques on some gilded-copper fragments from the Moche site of Loma Negra, in the Piura Valley, on the Northern Coast of Perú are presented in this article. A previous radiocarbon dating of a wooden fragment indicated that Loma Negra was occupied around 295 AD. A PIXE analysis using a 2.6 MeV external proton beam, was used to obtain the concentration of trace elements in the samples. RBS analyses using 2.72 MeV 4He+ and 12.0 MeV 12C3+ were used to obtain the Au, Ag, Cu atomic profiles. NRA with a 1.02 MeV deuteron beam was used to measure the oxygen and carbon concentrations through the 16O(d,p) 17O, 16O(d,α) 14N and 12C(d,p0) 13C reactions.

Monetary alloys in Iron Age Armorica (Finistère, France): The singular case of the Osismi tribe

NASA Astrophysics Data System (ADS)

Guerra, M. F.; Abollivier, Ph.

2016-06-01

The analysis by PIXE and PAA of 64 coins struck in Iron Age Armorica by the Osismi tribe revealed the use of a different system from the usual Celtic Gaul tri-metallic system. The gold-based alloy (Au-Ag-Cu) firstly issued is debased over time to become a silver-based alloy (Ag-Cu-Sn). Based on the analytical data, two chronological phases were defined and dates of issuing could be ascribed to the coin-types. The presence of Sn and Sb in the alloys and the low contents of Pb were used in the attribution of 9 specimens of unknown origin to the Osismi monetary system. Considerations on the mints supplies could also be provided.

Forensic practice in the field of protection of cultural heritage

NASA Astrophysics Data System (ADS)

Kotrlý, Marek; Turková, Ivana

2012-06-01

Microscopic methods play a key role in issues covering analyses of objects of art that are used on the one hand as screening ones, on the other hand they can lead to obtaining data relevant for completion of expertise. Analyses of artworks, gemmological objects and other highly valuable commodities usually do not rank among routine ones, but every analysis is specific, be it e.g. material investigation of artworks, historical textile materials and other antiques (coins, etc.), identification of fragments (from transporters, storage places, etc.), period statues, sculptures compared to originals, analyses of gems and jewellery, etc. A number of analytical techniques may be employed: optical microscopy in transmitted and reflected light, polarization and fluorescence in visible, UV and IR radiation; image analysis, quantitative microspectrophotometry; SEM/EDS/WDS; FTIR and Raman spectroscopy; XRF and microXRF, including mobile one; XRD and microXRD; x-ray backlight or LA-ICP-MS, SIMS, PIXE; further methods of organic analysis are also utilised - GS-MS, MALDI-TOF, etc.

A flexible and accurate quantification algorithm for electron probe X-ray microanalysis based on thin-film element yields

NASA Astrophysics Data System (ADS)

Schalm, O.; Janssens, K.

2003-04-01

Quantitative analysis by means of electron probe X-ray microanalysis (EPXMA) of low Z materials such as silicate glasses can be hampered by the fact that ice or other contaminants build up on the Si(Li) detector beryllium window or (in the case of a windowless detector) on the Si(Li) crystal itself. These layers act as an additional absorber in front of the detector crystal, decreasing the detection efficiency at low energies (<5 keV). Since the layer thickness gradually changes with time, also the detector efficiency in the low energy region is not constant. Using the normal ZAF approach to quantification of EPXMA data is cumbersome in these conditions, because spectra from reference materials and from unknown samples must be acquired within a fairly short period of time in order to avoid the effect of the change in efficiency. To avoid this problem, an alternative approach to quantification of EPXMA data is proposed, following a philosophy often employed in quantitative analysis of X-ray fluorescence (XRF) and proton-induced X-ray emission (PIXE) data. This approach is based on the (experimental) determination of thin-film element yields, rather than starting from infinitely thick and single element calibration standards. These thin-film sensitivity coefficients can also be interpolated to allow quantification of elements for which no suitable standards are available. The change in detector efficiency can be monitored by collecting an X-ray spectrum of one multi-element glass standard. This information is used to adapt the previously determined thin-film sensitivity coefficients to the actual detector efficiency conditions valid on the day that the experiments were carried out. The main advantage of this method is that spectra collected from the standards and from the unknown samples should not be acquired within a short period of time. This new approach is evaluated for glass and metal matrices and is compared with a standard ZAF method.

A Glimpse of the Very Early Universal Web

NASA Astrophysics Data System (ADS)

2001-05-01

The VLT Maps Extremely Distant Galaxies Summary New, trailblazing observations with the ESO Very Large Telescope (VLT) at Paranal lend strong support to current computer models of the early universe: It is "spongy", with galaxies forming along filaments, like droplets along the strands of a spiders web. A group of astronomers at ESO and in Denmark [1] determined the distances to some very faint galaxies in the neighbourhood of a distant quasar. Plotting their positions in a three-dimensional map, they found that these objects are located within a narrow "filament", exactly as predicted by the present theories for the development of the first structures in the young universe . The objects are most likely "building blocks" from which galaxies and clusters of galaxies assemble. This observation shows a very useful way forward for the study of the early evolution of the universe and the emergence of structures soon after the Big Bang. At the same time, it provides yet another proof of the great power of the new class of giant optical telescopes for cosmological studies. PR Photo 19a/01 : Web-like structures in the young Universe (computer model). PR Photo 19b/01 : A group of objects at redshift 3.04 . PR Photo 19c/01 : Animated view of sky field and distant filament . PR Photo 19d/01 : The shape of the filament . PR Photo 19e/01 : Artist's impression of the very distant filament. PR Video Clip 04/01 : Video animation of the very distant filament. The computers are ahead of the telescopes For the past two decades cosmologists have been in the somewhat odd situation that their computers were "ahead" of their telescopes. The rapid evolution of powerful computer hardware and sophisticated software has provided theorists with the ability to build almost any sort of virtual universe they can imagine. Starting with different initial conditions just after the Big Bang, they can watch such fictional worlds evolve over billions of years in their supercomputers - and do so in a matter of days only. This has made it possible to predict what the universe might look like when it was still young. And working the opposite way, a comparison between the computer models and the real world might then provide some information about the initial conditions. Unfortunately, until recently astronomical telescopes were not sufficiently powerful to directly study the "real world" of the young universe by observing in detail the extremely faint objects at that early epoch, and thereby to test the predictions. Now, however, the advent of giant telescopes of the 8-10 metre class has changed this situation and a group of astronomers has used the ESO Very Large Telescope (VLT) at Paranal Observatory (Chile) to view a small part of the early cosmic structure. The telescopes have begun to catch up with the computer simulations. First Structures of the Universe ESO PR Photo 19a/01 ESO PR Photo 19a/01 [Preview - JPEG: 353 x 400 pix - 304k] [Normal - JPEG: 706 x 800 pix - 952k] Caption : Computer model of the universe at an age of about 2 billion years (i.e., at redshift 3, see the text). In the simulated universe gravity causes the primordial matter to arrange itself in thin filaments, much like a spider's web. The colour coding indicates the density of the gas, yellow for highest, red for medium, and blue for the lowest density. In the high density (yellow) regions the gas will undergo collapse and ignite bursts of star formation. Those small star-forming regions will slowly stream along the filaments. When they meet at the intersections (the "nodes"), they will merge and cause a gradual build-up of the galaxies we know today. In this sense they are the building blocks of which galaxies are made. This simulated image was computed by Tom Theuns at the Max-Planck-Institute for Astrophysics, Garching, Germany, and kindly made available for this Press Release (please be sure to quote the source). All recent computer-simulations of the early universe have one prediction in common: the first large-scale structures to form in the young universe are long filaments connected at their ends in "nodes" . The models typically look like a three-dimensional spider's web, and resemble the neural structure of a brain ( PR Photo 19a/01 ). The first galaxies or rather, the first galaxy building blocks , will form inside the threads of the web. When they start emitting light, they will be seen to mark out the otherwise invisible threads, much like beads on a string. In the course of millions and billions of years, those early galaxies will stream along these threads, towards and into the "nodes". This is where galaxy clusters will later be formed, cf. ESO PR 13/99. During this process the structure of the universe slowly changes. From being dominated by filaments, it becomes populated by large clusters of galaxies that are still connected by "bridges" and "walls", the last remains of the largest of the original filaments. The Lyman-alpha spectral line New observations with the ESO Very Large Telescope have now identified a string of galaxies that map out a tight filament in the early universe. This trailblazing result is reported by a team of astronomers from ESO and Denmark [1], who have been searching for compact clumps of hydrogen in the early universe. Hydrogen was formed during the Big Bang some 15 billion years ago and is by far the most common element in the universe. When stars are formed by contraction inside a large and compact clump of hydrogen in space, the surrounding hydrogen cloud will absorb the ultraviolet light from the newborn stars, and this cloud will soon start to glow. This glow is mostly emitted at a single wavelength at 121.6 nm (1216 Å), the "Lyman-alpha" emission line of hydrogen. This wavelength is in the ultraviolet part of the spectrum to which the terrestrial atmosphere is totally opaque. Accordingly, the Lyman-alpha emission can normally not be observed by ground-based telescopes. However, if a very distant hydrogen cloud emits Lyman-alpha radiation, then this spectral line will be red-shifted from the ultraviolet into the blue, green or red region of the spectrum [2]. For this reason, observations with large ground-based telescopes of Lyman-alpha radiation can be used to identify faint objects forming inside the high-redshift filaments. The team refers to such objects as the LEGO-blocks of cosmology ("Lyman-alpha Emitting Galaxy-building Objects") [3]. VLT confirms the predictions ESO PR Photo 19b/01 ESO PR Photo 19b/01 [Preview - JPEG: 400 x 276 pix - 95k] [Normal - JPEG: 800 x 551 pix - 216k] [Hi-Res - JPEG: 3000 x 2067 pix - 1.4Mb] ESO PR Photo 19c/01 ESO PR Photo 19c/01 [Animated GIF: 369 x 369 pix - 67k] Caption : PR Photo 19b/01 is a "true-colour" image of part of the sky field near the quasar Q 1205-30 . Red, blue and yellow objects are displayed with their true colours, while objects at a redshift of about 3 and with strong Lyman-alpha emission lines have a bright green colour (see the text). Six Lyman-alpha Emitting Galaxy-building Objects (LEGOs for short) are marked by hexagons. The quasar (at the lower left) is marked by a larger hexagon and is seen to have an extended Lyman-alpha cloud in front of it, here visible as extended green light. In PR Photo 19c/01 , the entire sky field is shown, as observed through the blue filter. The quasar is marked by a red hexagon while the LEGOs are indicated by yellow hexagons. A total of eight objects at redshift 3.04 are identified. One is located in front of the quasar and was found by means of its absorption of the quasar light, while the seven other objects were identified by their Lyman-alpha emission. As explained in the text, all these objects are found to lie inside a thin filament, here visualized in an animated GIF-display. Almost all of the other objects seen in this deep image are either stars in the outskirts of our own Milky Way galaxy or faint galaxies lying between us and the distant filament. Technical information about these photos is available below. Already in 1998, the present team of astronomers obtained very deep images with the ESO 3.58-m New Technology Telescope (NTT) at the La Silla Observatory (Chile) of the sky field around the quasar Q1205-30 . The redshift of this distant object has been measured as z = 3.04, corresponding to a look-back time of about 85% of the age of the Universe. Assuming this to be about 15 billion years, we now observe the quasar as it appeared 13 billion years ago, hence about 2 billion years after the Big Bang. The images were obtained through a special optical filter that only allows light in a narrow spectral waveband to pass. The astronomers chose this wavelength to coincide with that of the Lyman-alpha emission line redshifted to z = 3.04, i.e. 490 nm in the green spectral region. Lyman-alpha radiation from objects at the distance of the quasar - and thus, at nearly the same redshift - will pass through this optical filter. When these images are combined with other deep images taken through much wider red and blue filters, the Lyman-alpha emitting objects at redshift 3.04 will show up as small, intensely green objects, while most other objects in the field will appear in various shades of red, blue and yellow, cf. PR Photo 19b/01 . The spatial distribution of the galaxies ESO PR Photo 19d/01 ESO PR Photo 19d/01 [Preview - JPEG: 400 x 241 pix - 39k] [Normal - JPEG: 800 x 481 pix - 120k] ESO PR Photo 19e/01 ESO PR Photo 19e/01 [Preview - JPEG: 260 x 400 pix - 71k] [Normal - JPEG:5190 x 800 pix - 224k] [Hi-Res - JPEG: 1948 x 3000 pix - 1.5Mb] A Cosmic Filament at z=3.04 - PR Video Clip 04/01 [MPEG - 3.6Mb] ESO PR Video Clip 04/01 "A Cosmic Filament at z=3.04" (May 2001) (1000 frames/40 sec) [MPEG Video; 192x144 pix; 3.6Mb] [MPEG Video; 384x288 pix; 9.6Mb] [RealMedia; streaming; 56kps] [RealMedia; streaming; 200kps] Caption : PR Photo 19d/01 shows the three-dimensional distribution of the observed LEGOs (the hexagons); the three space co-ordinates being determined by the position in the sky and the distance (from the measured redshift, see the text). They are clearly located along a rather narrow filament, here indicated by a hollow cylinder seen from the front (left) and from the side (right). The surrounding box is drawn to facilitate the 3-D comprehension - it measures approximately 8.8 x 8.8 x 13.3 million light-years. PR Photo 19e/01 provides another view of the filament from a different angle, as well as an artist's impression (in colour). The eye represents the viewing angle of the telescope, see also PR Photo 19c/01 . PR Video Clip 04/01 provides an animated view of the spatial configuration of the filaments and the observed objects. Thanks to the great light-gathering capabilily of the VLT and the excellent FORS1 multi-mode instrument at the 8.2-m ANTU telescope, spectra of eight, faint Lyman-alpha objects were obtained in March 2000 that allowed measuring their exact redshifts and hence, their distances [2]. When two co-ordinates from the position in the sky were combined with the measured redshifts into a three-dimensional map, the astronomers found that all of the objects lie within a thin, well-defined filament , cf. PR Photos 19d/01 and 19e/01 . Speaking for the group, Palle Møller is exhilarated: " We have little doubt that for the first time, we are here seeing a small cosmic filament in the early universe. At this enormous distance and correspondingly long look-back time, we see it at a time when the universe was only about 2 billion years old. This is obviously in agreement with the predictions by the computer models of a web-like structure, lending further strong support to our current picture of the early development of the universe in which we live ". Implications of this discovery Does this observation change our view of the early universe? No - on the contrary, it confirms the predictions of computer-models about how cosmic structures formed in the early days after the Big Bang. The most important ingredient in the cosmological models is the dark matter that is believed to contribute about 95% of the mass of the universe. The present confirmation of the predictions of the models therefore also indirectly confirms that it is the dark matter that controls the formation of structures in the universe. However, there is still a long way to go before it will be possible to make a more detailed comparison between observations and predictions, e.g., from PR Photo 19e/01 to PR Photo 19a/01 ! Asked about what they consider the most important consequence of their observations, the team responds: " We have shown that we now have an observational method with which we may study the cosmic web in the early universe, and the VLT is a great tool for such studies. The way forward is now pretty clear - we just have to find those faint and distant LEGOs and then do the spectral observations from which we may determine how they are distributed in space ". More information The research described in this press release is the subject of a scientific article by the team, "Detection of a redshift 3.04 filament" , to appear as a Letter to the Editor in the European journal Astronomy & Astrophysics. Notes [1] The team consists of Palle Møller , Johan Fynbo (both at ESO, Garching) and Bjarne Thomsen (Institute of Physics and Astronomy, Aarhus, Denmark). [2] In astronomy, the redshift denotes the fraction by which the lines in the spectrum of an object are shifted towards longer wavelengths. The observed redshift of a distant hydrogen cloud or galaxy gives a direct estimate of the apparent recession velocity as caused by the universal expansion. Since the expansion rate increases with the distance, the velocity is itself a function (the Hubble relation) of the distance to the object. The higher the redshift of an object, the more distant it is and the longer is the look-back time, i.e. the earlier is the corresponding epoch. [3] See also ESO Press Release 13/99 and ESO Press Release 08/00 (Report F). Technical information about the photos PR Photo 19b/01 is a colour composite, based on three images. The green channel is based on images with a total exposure time of 17.8 hours, obtained through a 2 nm wide, optical filter, centred at wavelength 490.6 nm and obtained in 1998 with the SuSI2 instrument at the ESO 3.58-m New Technology Telescope (NTT) on La Silla. The blue and red channels are based on 13 400-sec exposures in a B-filter and 15 250-sec exposures in an I-filter, respectively, both obtained with 8.2-m VLT ANTU telescope and the multi-mode FORS1 instrument. The field measures 3.0 x 1.8 arcmin 2. North is up and East is left. PR Photo 19c/01 is based on 13 400-sec exposures in a B(lue) optical filter, obtained with VLT ANTU and the multi-mode FORS1 instrument in March 2000. The seeing was 0.7 - 1.0 arcsec and the field measures 6.8 x 6.8 arcmin 2. North is up and East is left.

New Fast Lane towards Discoveries of Clusters of Galaxies Inaugurated

NASA Astrophysics Data System (ADS)

2003-07-01

Space and Ground-Based Telescopes Cooperate to Gain Deep Cosmological Insights Summary Using the ESA XMM-Newton satellite, a team of European and Chilean astronomers [2] has obtained the world's deepest "wide-field" X-ray image of the cosmos to date. This penetrating view, when complemented with observations by some of the largest and most efficient ground-based optical telescopes, including the ESO Very Large Telescope (VLT), has resulted in the discovery of several large clusters of galaxies. These early results from an ambitious research programme are extremely promising and pave the way for a very comprehensive and thorough census of clusters of galaxies at various epochs. Relying on the foremost astronomical technology and with an unequalled observational efficiency, this project is set to provide new insights into the structure and evolution of the distant Universe. PR Photo 19a/03: First image from the XMM-LSS survey. PR Photo 19b/03: Zoom-in on PR Photo 19b/03. PR Photo 19c/03: XMM-Newton contour map of the probable extent of a cluster of galaxies, superimposed upon a CHFT I-band image. PR Photo 19d/03: Velocity distribution in the cluster field shown in PR Photo 19c/03. The universal web Unlike grains of sand on a beach, matter is not uniformly spread throughout the Universe. Instead, it is concentrated into galaxies which themselves congregate into clusters (and even clusters of clusters). These clusters are "strung" throughout the Universe in a web-like structure, cf. ESO PR 11/01. Our Galaxy, the Milky Way, for example, belongs to the so-called Local Group which also comprises "Messier 31", the Andromeda Galaxy. The Local Group contains about 30 galaxies and measures a few million light-years across. Other clusters are much larger. The Coma cluster contains thousands of galaxies and measures more than 20 million light-years. Another well known example is the Virgo cluster, covering no less than 10 degrees on the sky ! Clusters of galaxies are the most massive bound structures in the Universe. They have masses of the order of one thousand million million times the mass of our Sun. Their three-dimensional space distribution and number density change with cosmic time and provide information about the main cosmological parameters in a unique way. About one fifth of the optically invisible mass of a cluster is in the form of a diffuse hot gas in between the galaxies. This gas has a temperature of the order of several tens of million degrees and a density of the order of one atom per liter. At such high temperatures, it produces powerful X-ray emission. Observing this intergalactic gas and not just the individual galaxies is like seeing the buildings of a city in daytime, not just the lighted windows at night. This is why clusters of galaxies are best discovered using X-ray satellites. Using previous X-ray satellites, astronomers have performed limited studies of the large-scale structure of the nearby Universe. However, they so far lacked the instruments to extend the search to large volumes of the distant Universe. The XMM-Newton wide-field observations ESO PR Photo 19a/03 ESO PR Photo 19a/03 [Preview - JPEG: 575 x 400 pix - 52k [Normal - JPEG: 1130 x 800 pix - 420k] ESO PR Photo 19b/03 ESO PR Photo 19b/03 [Preview - JPEG: 400 x 489 pix - 52k [Normal - JPEG: 800 x 978 pix - 464k] Captions: PR Photo 19a/03 is the first image from the XMM-LSS X-Ray survey. It is actually a combination of fourteen separate "pointings" of this space observatory. It represents a region of the sky eight times larger than the full Moon and contains around 25 clusters. The circles represent the X-Ray sources previously known from the 1991 ROSAT All-Sky Survey. PR Photo 19b/03 zooms in on a particularly interesting region of the image shown in ESO PR Photo 19a/03 with a possible cluster identified (in box). Each point on this graph represents a single X-ray photon detected by XMM-Newton. Marguerite Pierre (CEA Saclay, France), with a European/Chilean team of astronomers known as the XMM-LSS consortium [2], used the large field-of-view and the high sensitivity of ESA's X-ray observatory XMM-Newton to search for remote clusters of galaxies and map out their distribution in space. They could see back about 7,000 million years to a cosmological era when the Universe was about half its present size and age, when clusters of galaxies were more tightly packed. Tracking down the clusters is a painstaking, multi-step process, requiring both space and ground-based telescopes. Indeed, from X-ray images with XMM, it was possible to select several tens of cluster candidate objects, identified as areas of enhanced X-radiation (cf PR Photo 19b/03). But having candidates is not enough ! They must be confirmed and further studied with ground-based telescopes. In tandem with XMM-Newton, Pierre uses the very-wide-field imager attached to the 4-m Canada-France-Hawaii Telescope, on Mauna Kea, Hawaii, to take an optical snapshot of the same region of space. A tailor-made computer programme then combs the XMM-Newton data looking for concentrations of X-rays that suggest large, extended structures. These are the clusters and represent only about 10% of the detected X-ray sources. The others are mostly distant active galaxies. Back to the Ground ESO PR Photo 19c/03 ESO PR Photo 19c/03 [Preview - JPEG: 400 x 481 pix - 84k [Normal - JPEG: 800 x 961 pix - 1M] ESO PR Photo 19d/03 ESO PR Photo 19d/03 [Preview - JPEG: 400 x 488 pix - 44k [Normal - JPEG: 800 x 976 pix - 520k] Captions: PR Photo 19c/03 represents the XMM-Newton X-ray contour map of the cluster's probable extent superimposed upon the CFHT I-band image. A concentration of distant galaxies is conspicuous, thus confirming the X-ray detection. The symbols indicate the galaxies which have been subject to a subsequent spectroscopic measurement and found to be cluster members (triangles flag emission line galaxies). The individual galaxies in the cluster can then be targeted for further observations with ESO's VLT, in order to measure its distance and locate the cluster in the universe. Following the X-ray discovery and the optical cluster identification, galaxies in the cluster field shown in ESO PR Photo 19c/03 have been spectroscopically observed at the ESO VLT using the FORS2 instrument in order to determine the cluster redshift [3]. Using two masks, each of them observed during one hour, allowing to take the spectra of 16 emission-line galaxies at a time, the cluster was found to have a redshift of 0.84, corresponding to a distance of 8,000 million light-years, and a velocity dispersion of 750 km/s. PR Photo 19d/03 shows the measured velocity distribution. This is one of the most distant known clusters of galaxies for which a velocity dispersion has been measured. When the programme finds a cluster, it zooms in on that region and converts the XMM-Newton data into a contour map of X-ray intensity, which is then superimposed upon the CFHT optical image (PR Photo 19c/03). The astronomers use this to check if anything is visible within the area of extented X-ray emission. If something is seen, the work then shifts to one of the world's prime optical/infrared telescopes, the European Southern Observatory's Very Large Telescope (VLT) at Paranal (Chile). By means of the FORS multi-mode instruments, the astronomers zoom-in on the individual galaxies in the field, taking spectral measurements that reveal their overall characteristics, in particular their redshift and hence, distance. Cluster galaxies have similar distances and these measurement ultimately provide, by averaging, the cluster's distance as well as the velocity dispersion in the cluster. The FORS instruments are among the most efficient and versatile for this type of work, taking on the average spectra of 30 galaxies at a time. The first spectroscopic observations dedicated to the identification and redshift measurement of the XMM-LSS galaxy clusters took place during three nights in the fall of 2002. As of March 2003, there were only 5 known clusters in the literature at such a large redshift with enough spectroscopically measured redshifts to allow an estimate of the velocity dispersion. But the VLT allowed obtaining the dispersion in a distant cluster in 2 hours only, raising great expectations for future work. 700 spectra... Marguerite Pierre is extremely content : Weather and working conditions at the VLT were optimal. In three nights only, 12 cluster fields were observed, yielding no less than 700 spectra of galaxies. The overall strategy proved very successful. The high observing efficiency of the VLT and FORS support our plan to perform follow-up studies of large numbers of distant clusters with relatively little observing time. This represents a most substantial increase in efficiency compared to former searches. The present research programme has begun well, clearly demonstrating the feasibility of this new multi-telescope approach and its very high efficiency. And Marguerite Pierre and her colleagues are already seeing the first tantalising results: it seems to confirm that the number of clusters 7,000 million years ago is little different from that of today. This particular behaviour is predicted by models of the Universe that expand forever, driving the galaxy clusters further and further apart. Equally important, this multi-wavelength, multi-telescope approach developed by the XMM-LSS consortium to locate clusters of galaxies also constitutes a decisive next step in the fertile synergy between space and ground-based observatories and is therefore a basic building block of the forthcoming Virtual Observatory. More information This work is based on two papers to be published in the professional astronomy journal, Astronomy and Astrophysics (The XMM-LSS survey : I. Scientific motivations, design and first results by Marguerite Pierre et al., astro-ph/0305191 and The XMM-LSS survey : II. First high redshift galaxy clusters: relaxed and collapsing systems by Ivan Valtchanov et al., astro-ph/0305192). Dr. M. Pierre will give an invited talk on this subject at the IAU Symposium 216 - Maps of the Cosmos - this Thursday July 17, 2003 during the IAU General Assembly 2003 in Sydney, Australia.

Isolated Star-Forming Cloud Discovered in Intracluster Space

NASA Astrophysics Data System (ADS)

2003-01-01

Subaru and VLT Join Forces in New Study of Virgo Galaxy Cluster [1] Summary At a distance of some 50 million light-years, the Virgo Cluster is the nearest galaxy cluster. It is located in the zodiacal constellation of the same name (The Virgin) and is a large and dense assembly of hundreds of galaxies. The "intracluster" space between the Virgo galaxies is permeated by hot X-ray emitting gas and, as has become clear recently, by a sparse "intracluster population of stars". So far, stars have been observed to form in the luminous parts of galaxies. The most massive young stars are often visible indirectly by the strong emission from surrounding cocoons of hot gas, which is heated by the intense radiation from the embedded stars. These "HII regions" (pronounced "Eitch-Two" and so named because of their content of ionized hydrogen) may be very bright and they often trace the beautiful spiral arms seen in disk galaxies like our own Milky Way. New observations by the Japanese 8-m Subaru telescope and the ESO Very Large Telescope (VLT) have now shown that massive stars can also form in isolation, far from the luminous parts of galaxies. During a most productive co-operation between astronomers working at these two world-class telescopes, a compact HII region has been discovered at the very boundary between the outer halo of a Virgo cluster galaxy and Virgo intracluster space. This cloud is illuminated and heated by a few hot and massive young stars. The estimated total mass of the stars in the cloud is only a few hundred times that of the Sun. Such an object is rare at the present epoch. However, there may have been more in the past, at which time they were perhaps responsible for the formation of a fraction of the intracluster stellar population in clusters of galaxies. Massive stars in such isolated HII regions will explode as supernovae at the end of their short lives, and enrich the intracluster medium with heavy elements. Observations of two other Virgo cluster galaxies, Messier 86 and Messier 84, indicate the presence of other isolated HII regions, thus suggesting that isolated star formation may occur more generally in galaxies. If so, this process may provide a natural explanation to the current riddle why some young stars are found high up in the halo of our own Milky Way galaxy, far from the star-forming clouds in the main plane. The Virgo Cluster ESO PR Photo 04a/03 ESO PR Photo 04a/03 [Preview - JPEG: 400 x 428 pix - 74k [Normal - JPEG: 800 x 855 pix - 408k] [Hi-Res - JPEG: 4252 x 4544 pix - 10.3M] ESO PR Photo 04b/03 ESO PR Photo 04b/03 [Preview - JPEG: 433 x 400 pix - 60k [Normal - JPEG: 865 x 800 pix - 456k] [Hi-Res - JPEG: 3077 x 2847 pix - 4.2M] Captions: PR Photo 04a/03 displays a sky field near some of the brighter galaxies in the Virgo Cluster. It was obtained in April 2000 with the Wide Field Imager (WFI) at the La Silla Observatory (exposure 6 x 5 min; red R-band; seeing 1.3 arcsec). The large elliptical galaxy at the centre is Messier 84; the elongated image of NGC 4388 (an active spiral galaxy, seen from the side) is in the lower left corner. The field measures 16.9 x 15.7 arcmin2. PR Photo 04b/03 shows a larger region of the Virgo cluster, with the galaxies Messier 86 (at the upper edge of the field, to the left of the centre), as well as Messier 84 (upper right) and NGC 4388 (just below the centre) that are also seen in PR Photo 04a/03. It is reproduced from a long-exposure Subaru Suprime-Cam image, obtained in the red light of ionized hydrogen (the H-alpha spectral line at wavelength 656.2 nm). In order to show the faintest possible hydrogen emitting objects embedded in the outskirts of bright galaxies, their smooth envelopes have been "subtracted" during the image processing. The field measures 34 x 27 arcmin2. Part of this sky field is shown in colour in PR Photo 04c/03. Captions: PR Photo 04a/03 displays a sky field near some of the brighter galaxies in the Virgo Cluster. It was obtained in April 2000 with the Wide Field Imager (WFI) at the La Silla Observatory (exposure 6 x 5 min; red R-band; seeing 1.3 arcsec). The large elliptical galaxy at the centre is Messier 84; the elongated image of NGC 4388 (an active spiral galaxy, seen from the side) is in the lower left corner. The field measures 16.9 x 15.7 arcmin2. PR Photo 04b/03 shows a larger region of the Virgo cluster, with the galaxies Messier 86 (at the upper edge of the field, to the left of the centre), as well as Messier 84 (upper right) and NGC 4388 (just below the centre) that are also seen in PR Photo 04a/03. It is reproduced from a long-exposure Subaru Suprime-Cam image, obtained in the red light of ionized hydrogen (the H-alpha spectral line at wavelength 656.2 nm). In order to show the faintest possible hydrogen emitting objects embedded in the outskirts of bright galaxies, their smooth envelopes have been "subtracted" during the image processing. The field measures 34 x 27 arcmin2. Part of this sky field is shown in colour in PR Photo 04c/03. The galaxies in the Universe are rarely isolated - they prefer company. Many are found within dense structures, referred to as galaxy clusters, cf. e.g., ESO PR Photo 16a/99. The galaxy cluster nearest to us is seen in the direction of the zodiacal constellation Virgo (The Virgin), at a distance of approximately 50 million light-years. PR Photo 04a/03 (from the Wide Field Imager camera at the ESO La Silla Observatory) shows a small sky region near the centre of this cluster with some of the brighter cluster galaxies. PR Photo 04b/03 displays an image of a larger field (partially overlapping Photo 04a/03) in the light of ionized hydrogen - it was obtained by the Japanese 8.2-m Subaru telescope on Mauna Kea (Hawaii, USA). The field includes some of the large galaxies in this cluster, e.g., Messier 86, Messier 84 and NGC 4388. In order to show the faintest possible hydrogen emitting objects embedded in the outskirts of bright galaxies, their smooth envelopes have been "subtracted" during the image processing. This is why they look quite different in the two photos. Clusters of galaxies are believed to have formed because of the strong gravitational pull from dark and luminous matter. The Virgo cluster is considered to be a relatively young cluster, because studies of the distribution of its member galaxies and X-ray investigations of hot cluster gas have revealed small "subclusters of galaxies" around the major galaxies Messier 87, Messier 86 and Messier 49. These subclusters are yet to merge to form a dense and smooth galaxy cluster. The Virgo cluster is apparently cigar-shaped, with its longest dimension of about 10 million light-years near the line-of-sight direction - we see it "from the end". Stars in intracluster space Galaxy clusters are dominated by dark matter. The largest fraction of the luminous (i.e. "visible") cluster mass is made up of the hot gas that permeates all of the cluster. Recent observations of "intracluster" stars have confirmed that, in addition to the individual galaxies, the Virgo cluster also contains a so-called "diffuse stellar component", which is located in the space between the cluster galaxies. The first hint of this dates back to 1951 when Swiss astronomer Fritz Zwicky (1898-1974), working at the 5-m telescope at Mount Palomar in California (USA), claimed the discovery of diffuse light coming from the space between the galaxies in another large cluster of galaxies, the Coma cluster. The brightness of this intracluster light is 100 times fainter than the average night-sky brightness on the ground (mostly caused by the glow of atoms in the upper terrestrial atmosphere) and its measurement is difficult even with present technology. We now know that this intracluster glow comes from individual stars in that region. Planetary nebulae More recently, astronomers have undertaken a new and different approach to detect the elusive intracluster stars. They now search for Sun-like stars in their final dying phase during which they eject their outer layers into surrounding space. At the same time they unveil their small and hot stellar core which appears as a "white dwarf star". Such objects are known as "planetary nebulae" because some of those nearby, e.g. the "Dumbbell Nebula" (cf. ESO PR Photo 38a/98) resemble the disks of the outer solar system planets when viewed in small telescopes. The ejected envelope is illuminated and heated by the very hot star at its centre. This nebula emits strongly in characteristic emission lines of oxygen (green; at wavelengths 495.9 and 500.7 nm) and hydrogen (red; the H-alpha line at 656.2 nm). Planetary nebulae may be distinguished from other emission nebulae by the fact that their main green oxygen line at 500.7 nm is normally about 3 to 5 times brighter than the red H-alpha line. Search for intracluster planetary nebulae An international team of astronomers [2] is now carrying out a very challenging research programme, aimed at finding intracluster planetary nebulae. For this, they observe the regions between cluster galaxies with specially designed, narrow-band optical filters tuned to the wavelength of the green oxygen lines. The main goal is to study the overall properties of the diffuse stellar component in the nearby Virgo cluster. How much diffuse light comes from the intracluster space, how is it distributed within the cluster, and what is its origin? Because the stars in this region are apparently predominantly old, the most likely explanation of their presence in this region is that they formed inside individual galaxies, which were subsequently stripped of many of their stars during close encounters with other galaxies during the initial stages of cluster formation. These "lost" stars were then dispersed into intracluster space where we now find them. The Subaru observations ESO PR Photo 04c/03 ESO PR Photo 04c/03 [Preview - JPEG: 471 x 400 pix - 62k [Normal - JPEG: 941 x 800 pix - 776k] [Hi-Res - JPEG: 3028 x 2573 pix - 4.4M] ESO PR Photo 04d/03 ESO PR Photo 04d/03 [Preview - JPEG: 444 x 400 pix - 92k [Normal - JPEG: 888 x 800 pix - 600k] Captions: PR Photo 04c/03 shows the general location of the newly discovered compact HII region with respect to a previously published Subaru Suprime-Cam image of NGC 4388. The image combines H-alpha narrow-band (hydrogen), O[III] narrow-band (oxygen), and broad-band optical V-band data. The extended pink filamentary structure in this image is due to gas ionized by the radiation from the nucleus of the galaxy. The vertical lines are caused by detector saturation of bright objects. The field of view is 11.6 x 5.0 arcmin2. The outlined region indicates the sky field shown in PR Photo 04d/03 which is an H-alpha image of a 4 x 3 arcmin2 region in the Virgo intracluster region. This is part of the area selected for spectroscopic follow-up observations with the FORS2 multimode instrument at the 8.2-m VLT YEPUN telescope. The image shows the confirmed compact HII region (in blue circle to the left) and the confirmed intracluster planetary nebula (in yellow and red circle at the top). The two other objects (in red circles) are additional planetary nebulae candidates, which will soon be observed spectroscopically. North is up, and East is left. The newly discovered HII-region (blue circle) is well visible on PR Photo 04c/03 and faintly on the high-resolution versions of PR Photo 04a/03 and PR Photo 04b/03. Captions: PR Photo 04c/03 shows the general location of the newly discovered compact HII region with respect to a previously published Subaru Suprime-Cam image of NGC 4388. The image combines H-alpha narrow-band (hydrogen), O[III] narrow-band (oxygen), and broad-band optical V-band data. The extended pink filamentary structure in this image is due to gas ionized by the radiation from the nucleus of the galaxy. The vertical lines are caused by detector saturation of bright objects. The field of view is 11.6 x 5.0 arcmin2. The outlined region indicates the sky field shown in PR Photo 04d/03 which is an H-alpha image of a 4 x 3 arcmin2 region in the Virgo intracluster region. This is part of the area selected for spectroscopic follow-up observations with the FORS2 multimode instrument at the 8.2-m VLT YEPUN telescope. The image shows the confirmed compact HII region (in blue circle to the left) and the confirmed intracluster planetary nebula (in yellow and red circle at the top). The two other objects (in red circles) are additional planetary nebulae candidates, which will soon be observed spectroscopically. North is up, and East is left. The newly discovered HII-region (blue circle) is well visible on PR Photo 04c/03 and faintly on the high-resolution versions of PR Photo 04a/03 and PR Photo 04b/03. Japanese and European astronomers used the Suprime-Cam wide-field mosaic camera at the 8-m Subaru telescope (Mauna Kea, Hawaii, USA) to search for intracluster planetary nebulae in one of the densest regions of the Virgo cluster, cf. PR Photo 04b/03. They needed a telescope of this large size in order to select such objects and securely discriminate them from the thousands of foreground stars in the Milky Way and background galaxies. In particular, by observing in two narrow-band filters sensitive to oxygen and hydrogen, respectively, the planetary nebulae visible in this field could be "separated" from distant (high-redshift) background galaxies, which do not have strong emission in both the green and red band. It is very time-consuming to observe the weak H-alpha emission and this can only be done with a big telescope. Some 40 intracluster planetary nebulae candidates were found in this field which had the expected oxygen/H-alpha line intensity ratios of 3 - 5, such as those depicted PR Photo 04d/03. Unexpectedly, however, the data also showed a small number of star-like emission objects with oxygen/H-alpha line ratios of about 1. This is more typical of a cloud of ionized gas around young, massive stars - like the so-called HII regions in our own galaxy, the Milky Way. However, it would be very unusual to find such star formation regions in the intracluster region, so follow-up spectroscopic observations were clearly needed for confirmation. THE VLT MEASUREMENTS ESO PR Photo 04e/03 ESO PR Photo 04e/03 [Preview - JPEG: 506 x 400 pix - 35k [Normal - JPEG: 1011 x 800 pix - 128k] Captions: PR Photo 04e/03 displays the emission spectrum (in the visible/near-IR spectral region) of the compact HII region in the Virgo intracluster field, as obtained with the FORS2 multi-mode instrument of the 8.2-m VLT YEPUN telescope on Paranal. Emission lines from oxygen ([OIII]) and hydrogen (H-alpha, H-beta, H-gamma) atoms as well as ionized sulphur ([SII], [SIII]) are identified. The only way to make sure that these unusual objects are actually powered by young stars is by a detailed spectroscopical study, analyzing the emitted light over a wide range of wavelengths. One of the objects was observed in this way in April 2002 with the FORS2 multi-mode instrument at the 8.2-m VLT YEPUN telescope at the ESO Paranal Observatory (Chile). This was a most challenging observation, even for this very powerful facility, requiring several hours of exposure time. The brightness of the faint object (the flux of the oxygen [OIII 500.7]-line) was comparable to that of a 60-Watt light bulb at a distance of about 6.6 million km, i.e., about 17 times farther than the Moon. The recorded (long-slit) spectrum (PR Photo 04e/03) is indeed that of an HII region, with characteristic emission lines from hydrogen, oxygen and sulphur, and with underlying blue "continuum" emission from hot, young stars. This is the first concrete evidence that some of the ionized hydrogen gas in the intracluster medium near NGC 4388 is heated by massive stars, rather than radiation from the nucleus of the galaxy. Comparing the spectrum with simple starburst models showed that this HII region is "powered" by one or two hot and massive (O-type) stars. The best-fitting starburst model implies an estimated total mass of young stars of some 400 solar masses with an age of about 3 million years. The object is obviously very compact - it is indeed unresolved in all the images. The inferred radius of the HII region is about 11 light-years. Young stars form far from galaxies This compact star-forming region is located about 3.4 arcmin north and 0.9 arcmin west of the galaxy NGC 4388, corresponding to a distance of some 82,000 light-years (projected) from the main star-forming regions in this galaxy. The small cloud is moving away from us with an observed velocity of 2670 km/sec. This is considerably faster than the mean velocity of the Virgo cluster (about 1200 km/sec) but similar to that of NGC 4388 (2520 km/sec), indicating that it is probably falling through the Virgo cluster core together with NGC 4388, but it cannot have moved far during the comparatively short lifetime of its massive stars. It is not known whether it once was or still is bound to NGC 4388, or whether it only belonged to the surroundings that fell into the Virgo cluster with this galaxy. In any case, the existence of this HII region is a clear demonstration that stars can form in the "diffuse" outskirts of galaxies, if not in intracluster space. Because of internal dynamical processes, the stars in this object cannot remain forever in a dense cluster. Within a few hundred million years they will disperse and mix with the diffuse stellar population nearby. This isolated star formation is therefore likely to contribute to the intracluster stellar population, either directly, or after having moved away from the halo of NGC 4388. This mode of isolated star formation does not contribute much to the total intracluster light emission - at the current rate it can explain only a small fraction of the diffuse light now observed in this region. However, it may have been more significant in the past, when protogalaxies and proto-galaxy groups, rich in neutral gas and with gas clouds at large distances from their centers, fell into the forming Virgo cluster for the first time. Prospects The existence of isolated compact HII regions like this one is important as a very different site of star formation than those normally seen in galaxies. The massive stars born in such isolated clouds will explode as supernovae and enrich the Virgo intracluster medium with metals. Other possible - but not yet spectroscopically verified - compact HII regions in the halos of both Messier 86 and Messier 84 have been detected during this work. This finding thus also calls into question the current use of emission-line planetary nebulae luminosities as a distance indicator; to obtain the best possible accuracy, it will henceforth be necessary to weed out possible HII regions in the samples. If compact HII regions exist generally in galaxies, they may possibly be the birthplaces of some of the young stars now observed in the halo of our Milky Way galaxy, high above the main plane. Observational programmes with both the Subaru and VLT telescopes are now planned to discover more of these interesting objects and to explore their properties.

Elemental analyses on porcelains of Tang and Song Dynasties excavated from Yongjinwan zone at Jinsha site

NASA Astrophysics Data System (ADS)

Xia, C. D.; Ge, L. J.; Liu, M. T.; Zhu, J. J.; An, Z.; Bai, B.

2018-02-01

The work presented here carried out elemental analyses on 60 porcelain shards of Tang and Song Dynasties, unearthed from Yongjinwan zone at Jinsha site, Sichuan, China, using a combination of PIXE and RBS methods. Six shards from Liulichang kiln site and 6 from Shifangtang kiln site were also analyzed as reference materials. The factor analyses for the elemental compositions in the bodies and glazes of the total 72 porcelain shards have been performed to explore their similarities and differences. Combining the results of factor analyses on elements in bodies and glazes and the classification by traditional archaeological criteria, the provenances for most of shards unearthed from Yongjinwan zone in Jinsha site could be determined. Majority of shards with a Qiong-kiln style were found as products of Liulichang kiln, this is consistent with Yongjinwan's geographical location and social environment, i.e., Yongjinwan was a suburban settlement nearest to Liulichang kiln in ancient times. Although both products of Liulichang kiln and Shifangtang kiln belonged to Qiong-kiln system and they shared a similar appearance such as red body and celadon glaze, there were distinct differences in chemical composition which could be unraveled by PIXE-RBS measurements and factor analysis. There were no apparent differences of chemical compositions for the same kinds of body and glaze between Tang and Song Dynasties, which may suggest that raw materials and production techniques for the same kinds of body and glaze continued between Tang and Song Dynasties. The chemical characteristics for each kind of body and glaze and the correlations between element composition and porcelain appearance were also obtained in this work.

PIXE analysis of some Nigerian anti-diabetic medicinal plants (II)

NASA Astrophysics Data System (ADS)

Olabanji, S. O.; Adebajo, A. C.; Omobuwajo, O. R.; Ceccato, D.; Buoso, M. C.; Moschini, G.

2014-01-01

Diabetes mellitus, a metabolic disease characterized by high blood glucose levels (hyperglycemia) due to defects in insulin secretion, or action, or both, is a debilitating disease leading to other complications and death of many people in the world. Some of the medicinal plants implicated in the herbal recipes for the treatment of diabetes in Nigeria have been reported. Additional medicinal plants used for the treatment of diabetes in Nigeria are presented in this work. These medicinal plants are becoming increasingly important and relevant as herbal drugs due to their use as antioxidants, nutraceuticals, food additives and supplements in combating diabetes. Elemental compositions of these anti-diabetic medicinal plants were determined using PIXE technique. The 1.8 MV collimated proton beam from the 2.5 MV AN 2000 Van de Graaff accelerator at Istituto Nazionale di Fisica Nucleare (INFN), Laboratori Nazionali di Legnaro (LNL) Legnaro (Padova) Italy was employed for the work. The results show the detection of twenty-one elements which include Mg, P, Ca, K, Mn, Cu, Zn, S, Cr, Co, Ni and V that are implicated in the regulation of insulin and the control of the blood-sugar levels in the human body. The entire plant of Boerhavia diffusa, Securidaca longipedunculata stem, leaves of Peperomia pellucida, Macrosphyra longistyla, Olax subscorpioidea, Phyllanthus muerillanus, Jatropha gossypifolia, Cassia occidentalis, Phyllanthus amarus, and leaf and stem of Murraya koenigii, which have high concentrations of these elements could be recommended as vegetables, nutraceuticals, food additives, supplements and drugs in the control and management of diabetes, if toxicity profiles indicate that they are safe. However, significantly high contents of Al and Si in the entire plant of Bryophyllum pinnatum, and As, Cr, and Cu in Ocimum gratissimum leaf suggest that these plants should be avoided by diabetic patients to prevent complications.

Monitoring impacts of air pollution: PIXE analysis and histopathological modalities in evaluating relative risks of elemental contamination.

PubMed

Ejaz, Sohail; Camer, Gerry Amor; Anwar, Khaleeq; Ashraf, Muhammad

2014-04-01

Environmental toxicants invariably affect all biological organisms resulting to sufferings ranging from subclinical to debilitating clinical conditions. This novel research aimed to determine the toxic burdens of increased environmental elements in some vital organs/tissues of the wild animals (starling, owl, crow and pigeon), exposed to air polluted environment were assessed using particle induced X-ray emission and histopathological approaches. The presence of significantly elevated amounts of elemental toxicants namely: Aluminum (Al), Chlorine (Cl), Iron (Fe), Potassium (K), Magnesium (Mg), Manganese (Mn), Silicon (Si) and Vanadium (V) from the skin, muscle, lungs, liver and kidney of sampled animals were in concurrence with the observed histopathological changes. The skin of sampled starling, owl, pigeon and crow spotlighted highly significant increase (P < 0.001) in Al, Cl, Mg and Si. Muscle samples with myodegenerative lesions and mineral depositions highlighted substantial augmentation (P < 0.001) in the amount of Al, Fe, Mn, Si and V. The lungs of starling, owl, and pigeon were severely intoxicated (P < 0.001) with increased amount of Al, Fe, K, Mn and Si producing pulmonary lesions of congestion, edema, pneumonitis and mineral debris depositions. Liver samples revealed that the sampled animals were laden with Cl, Fe, Mg, Mn and V with histopathological profound degenerative changes and hepatic necrosis. Kidney sections presented severe tubular degenerative and necrotic changes that may be attributed to increased amounts of Cl and Fe. These current findings implied that the environmental/elemental toxicants and the accompanying lesions that were discerned in the organs/tissues of sampled birds may as well be afflicting people living within the polluted area. Further assessment to more conclusively demonstrate correlations of current findings to those of the populace within the area is encouraged.

[Polyethylene abrasion: cause or consequence of an endoprosthesis loosening? Investigations of firm and loosened hip implants].

PubMed

Busse, B; Niecke, M; Püschel, K; Delling, G; Katzer, A; Hahn, M

2007-01-01

Periprosthetic tissue was analysed by the combination of different investigation techniques without destruction. The localisation and geometry of polyethylene abrasion particles were determined quantitatively to differentiate between abrasion due to function and abrasion due to implant loosening. Non-polyethylene particles from implant components which contaminate the tissue were micro-analytically measured. The results will help us to understand loosening mechanisms and thus lead to implant optimisations. A non-destructive particle analysis using highly sensitive proton-induced X-ray emission (PIXE) was developed to achieve a better histological allocation. Five autopsy cases with firmly fitting hip endoprosthesis (2 x Endo-Modell Mark III, 1 x St. Georg Mark II, LINK, Germany; 2 x Spongiosa Metal II, ESKA, Germany) were prepared as ground tissue specimens. Wear investigations were accomplished with a combined application of different microscopic techniques and microanalysis. The abrasion due to implant loosening was histologically evaluated on 293 loosened cup implants (St. Georg Mark II, LINK, Germany). Wear particles are heterogeneously distributed in the soft tissue. In cases of cemented prostheses, cement particles are dominating whereas metal particles could rarely be detected. The concentration of the alloy constituent cobalt (Co) is increased in the mineralised bone tissue. The measured co-depositions depend on the localisation and/or lifetime of an implant. Functional polyethylene (PE) abrasion needs to be differentiated from PE abrasion of another genesis (loosening, impingement) morphologically and by different tissue reactions. In the past a reduction of abrasion was targeted primarily by the optimisation of the bearing surfaces and tribology. The interpretation of our findings indicates that different mechanisms of origin in terms of tissue contamination with wear debris and the alloy should be included in the improvement of implants or implantation techniques.

High level leaching of heavy metals from colorful ceramic foodwares: a potential risk to human.

PubMed

Aderemi, Taiwo Adedoyin; Adenuga, Adeniyi Abiodun; Oyekunle, John Adekunle Oyedele; Ogunfowokan, Aderemi Okunola

2017-07-01

Ceramic foodwares are among the products used by people on daily basis without being cautious of exposures to heavy metals through possible leaching from the glaze ceramics. This study investigated the levels of heavy metals found in some commonly used ceramic foodwares in Nigeria with the aim of determining levels of human exposures through the use of the ceramics. To achieve this, acid digestion was carried out for the total metal concentrations and leaching tests were done using 4% acetic acid as a leaching agent. Metal concentrations were quantified using flame atomic absorption spectrometry (FAAS) and particle-induced X-ray emission spectrometry (PIXES) analysis. All the ceramic foodwares studied were found to contain varied amounts of heavy metals in their glazes, with concentrations in the range of 26.45-2071.46, 5.20-547.00, 1.24-2681.02, 2590.00-8848.40, 6.42-654.66, 112.69-649.95, 63.38-2518.51, and 3786.51-8249.44 μg g -1 for Pb, Cd, Zn, As, Cu, Cr, Mn, and Fe, respectively. Concentrations of the metals leached from the ceramics were in the range of 0.11-0.97, 0.01-0.28, 0.00-4.19, 1.93-15.00, 0.01-0.41, 0.09-0.60, 0.01-2.14, and 0.01-11.53 mgL -1 for Pb, Cd, Zn, As, Cu, Cr, Mn, and Fe, respectively. Comparing the ratio of the metals leached from the ceramic wares with those of the metal oxides in the ceramics, it was noticeable that not all the metals detected in the ceramic samples were domiciled in the glaze but in the clay materials used for the ceramics.

Spatial X-ray fluorescence micro-imaging of minerals in grain tissues of wheat and related genotypes.

PubMed

Singh, Sudhir P; Vogel-Mikuš, Katarina; Vavpetič, Primož; Jeromel, Luka; Pelicon, Primož; Kumar, Jitendra; Tuli, Rakesh

2014-08-01

Wheat and its related genotypes show distinct distribution patterns for mineral nutrients in maternal and filial tissues in grains. X-ray-based imaging techniques are very informative to identify genotypes with contrasting tissue-specific localization of different elements. This can help in the selection of suitable genotypes for nutritional improvement of food grain crops. Understanding mineral localization in cereal grains is important for their nutritional improvement. Spatial distribution of mineral nutrients (Mg, P, S, K, Ca, Fe, Zn, Mn and Cu) was investigated between and within the maternal and filial tissues in grains of two wheat cultivars (Triticum aestivum Cv. WH291 and WL711), a landrace (T. aestivum L. IITR26) and a related wild species Aegilops kotschyi, using micro-proton-induced X-ray emission (µ-PIXE) and micro-X-ray fluorescence (µ-XRF). Aleurone and scutellum were major storage tissues for macro (P, K, Ca and Mg) as well as micro (Fe, Zn, Cu and Mn) nutrients. Distinct elemental distribution patterns were observed in each of the four genotypes. A. kotschyi, the wild relative of wheat and the landrace, T. aestivum L. IITR26, accumulated more Zn and Fe in scutellum and aleurone than the cultivated wheat varieties, WH291 and WL711. The landrace IITR26, accumulated far more S in grains, Mn in scutellum, aleurone and embryo region, Ca and Cu in aleurone and scutellum, and Mg, K and P in scutellum than the other genotypes. Unlike wheat, lower Mn and higher Fe, Cu and Zn concentrations were noticed in the pigment strand of A. kotschyi. Multivariate statistical analysis, performed on mineral distribution in major grain tissues (aleurone, scutellum, endosperm and embryo region) resolved the four genotypes into distinct clusters.

Another Look at an Enigmatic New World

NASA Astrophysics Data System (ADS)

2005-02-01

VLT NACO Performs Outstanding Observations of Titan's Atmosphere and Surface On January 14, 2005, the ESA Huygens probe arrived at Saturn's largest satellite, Titan. After a faultless descent through the dense atmosphere, it touched down on the icy surface of this strange world from where it continued to transmit precious data back to the Earth. Several of the world's large ground-based telescopes were also active during this exciting event, observing Titan before and near the Huygens encounter, within the framework of a dedicated campaign coordinated by the members of the Huygens Project Scientist Team. Indeed, large astronomical telescopes with state-of-the art adaptive optics systems allow scientists to image Titan's disc in quite some detail. Moreover, ground-based observations are not restricted to the limited period of the fly-by of Cassini and landing of Huygens. They hence complement ideally the data gathered by this NASA/ESA mission, further optimising the overall scientific return. A group of astronomers [1] observed Titan with ESO's Very Large Telescope (VLT) at the Paranal Observatory (Chile) during the nights from 14 to 16 January, by means of the adaptive optics NAOS/CONICA instrument mounted on the 8.2-m Yepun telescope [2]. The observations were carried out in several modes, resulting in a series of fine images and detailed spectra of this mysterious moon. They complement earlier VLT observations of Titan, cf. ESO Press Photos 08/04 and ESO Press Release 09/04. The highest contrast images ESO PR Photo 04a/05 ESO PR Photo 04a/05 Titan's surface (NACO/VLT) [Preview - JPEG: 400 x 712 pix - 64k] [Normal - JPEG: 800 x 1424 pix - 524k] ESO PR Photo 04b/05 ESO PR Photo 04b/05 Map of Titan's Surface (NACO/VLT) [Preview - JPEG: 400 x 651 pix - 41k] [Normal - JPEG: 800 x 1301 pix - 432k] Caption: ESO PR Photo 04a/05 shows Titan's trailing hemisphere [3] with the Huygens landing site marked as an "X". The left image was taken with NACO and a narrow-band filter centred at 2 microns. On the right is the NACO/SDI image of the same location showing Titan's surface through the 1.6 micron methane window. A spherical projection with coordinates on Titan is overplotted. ESO PR Photo 04b/05 is a map of Titan taken with NACO at 1.28 micron (a methane window allowing it to probe down to the surface). On the leading side of Titan, the bright equatorial feature ("Xanadu") is dominating. On the trailing side, the landing site of the Huygens probe is indicated. ESO PR Photo 04c/05 ESO PR Photo 04c/05 Titan, the Enigmatic Moon, and Huygens Landing Site (NACO-SDI/VLT and Cassini/ISS) [Preview - JPEG: 400 x 589 pix - 40k] [Normal - JPEG: 800 x 1178 pix - 290k] Caption: ESO PR Photo 04c/05 is a comparison between the NACO/SDI image and an image taken by Cassini/ISS while approaching Titan. The Cassini image shows the Huygens landing site map wrapped around Titan, rotated to the same position as the January NACO SDI observations. The yellow "X" marks the landing site of the ESA Huygens probe. The Cassini/ISS image is courtesy of NASA, JPL, Space Science Institute (see http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=36222). The coloured lines delineate the regions that were imaged by Cassini at differing resolutions. The lower-resolution imaging sequences are outlined in blue. Other areas have been specifically targeted for moderate and high resolution mosaicking of surface features. These include the site where the European Space Agency's Huygens probe has touched down in mid-January (marked with the yellow X), part of the bright region named Xanadu (easternmost extent of the area covered), and a boundary between dark and bright regions. ESO PR Photo 04d/05 ESO PR Photo 04d/05 Evolution of the Atmosphere of Titan (NACO/VLT) [Preview - JPEG: 400 x 902 pix - 40k] [Normal - JPEG: 800 x 1804 pix - 320k] Caption: ESO PR Photo 04d/05 is an image of Titan's atmosphere at 2.12 microns as observed with NACO on the VLT at three different epochs from 2002 till now. Titan's atmosphere exhibits seasonal and meteorological changes which can clearly be seen here : the North-South asymmetry - indicative of changes in the chemical composition in one pole or the other, depending on the season - is now clearly in favour of the North pole. Indeed, the situation has reversed with respect to a few years ago when the South pole was brighter. Also visible in these images is a bright feature in the South pole, found to be presently dimming after having appeared very bright from 2000 to 2003. The differences in size are due to the variation in the distance to Earth of Saturn and its planetary system. The new images show Titan's atmosphere and surface at various near-infrared spectral bands. The surface of Titan's trailing side is visible in images taken through narrow-band filters at wavelengths 1.28, 1.6 and 2.0 microns. They correspond to the so-called "methane windows" which allow to peer all the way through the lower Titan atmosphere to the surface. On the other hand, Titan's atmosphere is visible through filters centred in the wings of these methane bands, e.g. at 2.12 and 2.17 microns. Eric Gendron of the Paris Observatory in France and leader of the team, is extremely pleased: "We believe that some of these images are the highest-contrast images of Titan ever taken with any ground-based or earth-orbiting telescope." The excellent images of Titan's surface show the location of the Huygens landing site in much detail. In particular, those centred at wavelength 1.6 micron and obtained with the Simultaneous Differential Imager (SDI) on NACO [4] provide the highest contrast and best views. This is firstly because the filters match the 1.6 micron methane window most accurately. Secondly, it is possible to get an even clearer view of the surface by subtracting accurately the simultaneously recorded images of the atmospheric haze, taken at wavelength 1.625 micron. The images show the great complexity of Titan's trailing side, which was earlier thought to be very dark. However, it is now obvious that bright and dark regions cover the field of these images. The best resolution achieved on the surface features is about 0.039 arcsec, corresponding to 200 km on Titan. ESO PR Photo 04c/04 illustrates the striking agreement between the NACO/SDI image taken with the VLT from the ground and the ISS/Cassini map. The images of Titan's atmosphere at 2.12 microns show a still-bright south pole with an additional atmospheric bright feature, which may be clouds or some other meteorological phenomena. The astronomers have followed it since 2002 with NACO and notice that it seems to be fading with time. At 2.17 microns, this feature is not visible and the north-south asymmetry - also known as "Titan's smile" - is clearly in favour in the north. The two filters probe different altitude levels and the images thus provide information about the extent and evolution of the north-south asymmetry. Probing the composition of the surface ESO PR Photo 04e/05 ESO PR Photo 04e/05 Spectrum of Two Regions on Titan (NACO/VLT) [Preview - JPEG: 400 x 623 pix - 44k] [Normal - JPEG: 800 x 1246 pix - 283k] Caption: ESO PR Photo 04e/05 represents two of the many spectra obtained on January 16, 2005 with NACO and covering the 2.02 to 2.53 micron range. The blue spectrum corresponds to the brightest region on Titan's surface within the slit, while the red spectrum corresponds to the dark area around the Huygens landing site. In the methane band, the two spectra are equal, indicating a similar atmospheric content; in the methane window centred at 2.0 microns, the spectra show differences in brightness, but are in phase. This suggests that there is no real variation in the composition beyond different atmospheric mixings. ESO PR Photo 04f/05 ESO PR Photo 04f/05 Imaging Titan with a Tunable Filter (NACO Fabry-Perot/VLT) [Preview - JPEG: 400 x 718 pix - 44k] [Normal - JPEG: 800 x 1435 pix - 326k] Caption: ESO PR Photo 04f/05 presents a series of images of Titan taken around the 2.0 micron methane window probing different layers of the atmosphere and the surface. The images are currently under thorough processing and analysis so as to reveal any subtle variations in wavelength that could be indicative of the spectral response of the various surface components, thus allowing the astronomers to identify them. Because the astronomers have also obtained spectroscopic data at different wavelengths, they will be able to recover useful information on the surface composition. The Cassini/VIMS instrument explores Titan's surface in the infrared range and, being so close to this moon, it obtains spectra with a much better spatial resolution than what is possible with Earth-based telescopes. However, with NACO at the VLT, the astronomers have the advantage of observing Titan with considerably higher spectral resolution, and thus to gain more detailed spectral information about the composition, etc. The observations therefore complement each other. Once the composition of the surface at the location of the Huygens landing is known from the detailed analysis of the in-situ measurements, it should become possible to learn the nature of the surface features elsewhere on Titan by combining the Huygens results with more extended cartography from Cassini as well as from VLT observations to come. More information Results on Titan obtained with data from NACO/VLT are in press in the journal Icarus ("Maps of Titan's surface from 1 to 2.5 micron" by A. Coustenis et al.). Previous images of Titan obtained with NACO and with NACO/SDI are accessible as ESO PR Photos 08/04 and ESO PR Photos 11/04. See also these Press Releases for additional scientific references.

The Atacama Large Millimeter Array (ALMA)

NASA Astrophysics Data System (ADS)

1999-06-01

The Atacama Large Millimeter Array (ALMA) is the new name [2] for a giant millimeter-wavelength telescope project. As described in the accompanying joint press release by ESO and the U.S. National Science Foundation , the present design and development phase is now a Europe-U.S. collaboration, and may soon include Japan. ALMA may become the largest ground-based astronomy project of the next decade after VLT/VLTI, and one of the major new facilities for world astronomy. ALMA will make it possible to study the origins of galaxies, stars and planets. As presently envisaged, ALMA will be comprised of up to 64 12-meter diameter antennas distributed over an area 10 km across. ESO PR Photo 24a/99 shows an artist's concept of a portion of the array in a compact configuration. ESO PR Video Clip 03/99 illustrates how all the antennas will move in unison to point to a single astronomical object and follow it as it traverses the sky. In this way the combined telescope will produce astronomical images of great sharpness and sensitivity [3]. An exceptional site For such observations to be possible the atmosphere above the telescope must be transparent at millimeter and submillimeter wavelengths. This requires a site that is high and dry, and a high plateau in the Atacama desert of Chile, probably the world's driest, is ideal - the next best thing to outer space for these observations. ESO PR Photo 24b/99 shows the location of the chosen site at Chajnantor, at 5000 meters altitude and 60 kilometers east of the village of San Pedro de Atacama, as seen from the Space Shuttle during a servicing mission of the Hubble Space Telescope. ESO PR Photo 24c/99 and ESO PR Photo 24d/99 show a satellite image of the immediate vicinity and the site marked on a map of northern Chile. ALMA will be the highest continuously operated observatory in the world. The stark nature of this extreme site is well illustrated by the panoramic view in ESO PR Photo 24e/99. High sensitivity and sharp images ALMA will be extremely sensitive to radiation at milllimeter and submillimeter wavelengths. The large number of antennas gives a total collecting area of over 7000 square meters, larger than a football field. At the same time, the shape of the surface of each antenna must be extremely precise under all conditions; the overall accuracy over the entire 12-m diameter must be better than 0.025 millimeters (25µm), or one-third of the diameter of a human hair. The combination of large collecting area and high precision results in extremely high sensitivity to faint cosmic signals. The telescope must also be able to resolve the fine details of the objects it detects. In order to do this at millimeter wavelengths the effective diameter of the overall telescope must be very large - about 10 km. As it is impossible to build a single antenna with this diameter, an array of antennas is used instead, with the outermost antennas being 10 km apart. By combining the signals from all antennas together in a large central computer, it is possible to synthesize the effect of a single dish 10 km across. The resulting angular resolution is about 10 milli-arcseconds, less than one-thousandth the angular size of Saturn. Exciting research perspectives The scientific case for this revolutionary telescope is overwhelming. ALMA will make it possible to witness the formation of the earliest and most distant galaxies. It will also look deep into the dust-obscured regions where stars are born, to examine the details of star and planet formation. But ALMA will go far beyond these main science drivers, and will have a major impact on virtually all areas of astronomy. It will be a millimeter-wave counterpart to the most powerful optical/infrared telescopes such as ESO's Very Large Telescope (VLT) and the Hubble Space Telescope, with the additional advantage of being unhindered by cosmic dust opacity. The first galaxies in the Universe are expected to become rapidly enshrouded in the dust produced by the first stars. The dust can dim the galaxies at optical wavelengths, but the same dust radiates brightly at longer wavelengths. In addition, the expansion of the Universe causes the radiation from distant galaxies to be shifted to longer wavelengths. For both reasons, the earliest galaxies at the epoch of first light can be found with ALMA, and the subsequent evolution of galaxies can be mapped over cosmic time. ALMA will be of great importance for our understanding of the origins of stars and planetary systems. Stellar nurseries are completely obscured at optical wavelengths by dense "cocoons" of dust and gas, but ALMA can probe deep into these regions and study the fundamental processes by which stars are assembled. Moreover, it can observe the major reservoirs of biogenic elements (carbon, oxygen, nitrogen) and follow their incorporation into new planetary systems. A particularly exciting prospect for ALMA is to use its exceptionally sharp images to obtain evidence for planet formation by the presence of gaps in dusty disks around young stars, cleared by large bodies coalescing around the stars. Equally fundamental are observations of the dying gasps of stars at the other end of the stellar lifecycle, when they are often surrounded by shells of molecules and dust enriched in heavy elements produced by the nuclear fires now slowly dying. ALMA will offer exciting new views of our solar system. Studies of the molecular content of planetary atmospheres with ALMA's high resolving power will provide detailed weather maps of Mars, Jupiter, and the other planets and even their satellites. Studies of comets with ALMA will be particularly interesting. The molecular ices of these visitors from the outer reaches of the solar system have a composition that is preserved from ages when the solar system was forming. They evaporate when the comet comes close to the sun, and studies of the resulting gases with ALMA will allow accurate analysis of the chemistry of the presolar nebula. The road ahead The three-year design and development phase of the project is now underway as a collaboration between Europe and the U.S., and Japan may also join in this effort. Assuming the construction phase begins about two years from now, limited operations of the array may begin in 2005 and the full array may become operational by 2009. Notes [1] Press Releases about this event have also been issued by some of the other organisations participating in this project: * CNRS (in French) * MPG (in German) * NOVA (in Dutch) * NRAO * NSF (ASCII and HTML versions) * PPARC [2] "ALMA" means "soul" in Spanish. [3] Additional information about ALMA is available on the web: * Articles in the ESO Messenger - "The Large Southern Array" (March 1998), "European Site Testing at Chajnantor" (December 1998) and "The ALMA Project" (June 1999), cf. http://www.eso.org/gen-fac/pubs/messenger/ * ALMA website at ESO at http://www.eso.org/projects/alma/ * ALMA website at the U.S. National Radio Astronomy Observatory (NRAO) at http://www.mma.nrao.edu/ * ALMA website in The Netherlands about the detectors at http://www.sron.rug.nl/alma/ ALMA/Chajnantor Video Clip and Photos ESO PR Video Clip 03/99 [MPEG-version] ESO PR Video Clip 03/99 (2450 frames/1:38 min) [MPEG Video; 160x120 pix; 2.1Mb] [MPEG Video; 320x240 pix; 10.0Mb] [RealMedia; streaming; 700k] [RealMedia; streaming; 2.3M] About ESO Video Clip 03/99 : This video clip about the ALMA project contains two sequences. The first shows a panoramic scan of the Chajnantor plain from approx. north-east to north-west. The Chajnantor mountain passes through the field-of-view and the perfect cone of the Licancabur volcano (5900 m) on the Bolivian border is seen at the end (compare also with ESO PR 24e/99 below. The second is a 52-sec animation with a change of viewing perspective of the array and during which the antennas move in unison. For convenience, the clip is available in four versions: two MPEG files of different sizes and two streamer-versions of different quality that require RealPlayer software. There is no audio. Note that ESO Video News Reel No. 5 with more related scenes and in professional format with complete shot list is also available. ESO PR Photo 24b/99 ESO PR Photo 24b/99 [Preview - JPEG: 400 x 446 pix - 184k] [Normal - JPEG: 800 x 892 pix - 588k] [High-Res - JPEG: 3000 x 3345 pix - 5.4M] Caption to ESO PR Photo 24b/99 : View of Northern Chile, as seen from the NASA Space Shuttle during a servicing mission to the Hubble Space Telescope (partly visible to the left). The Atacama Desert, site of the ESO VLT at Paranal Observatory and the proposed location for ALMA at Chajnantor, is seen from North (foreground) to South. The two sites are only a few hundred km distant from each other. Few clouds are seen in this extremely dry area, due to the influence of the cold Humboldt Stream along the Chilean Pacific coast (right) and the high Andes mountains (left) that act as a barrier. Photo courtesy ESA astronaut Claude Nicollier. ESO PR Photo 24c/99 ESO PR Photo 24c/99 [Preview - JPEG: 400 x 318 pix - 212k] [Normal - JPEG: 800 x 635 pix - 700k] [High-Res - JPEG: 3000 x 2382 pix - 5.9M] Caption to ESO PR Photo 24c/99 : This satellite image of the Chajnantor area was produced in 1998 at Cornell University (USA), by Jennifer Yu, Jeremy Darling and Riccardo Giovanelli, using the Thematic Mapper data base maintained at the Geology Department laboratory directed by Bryan Isacks. It is a composite of three exposures in spectral bands at 1.6 µm (rendered as red), 1.0 µm (green) and 0.5 µm (blue). The horizontal resolution of the false-colour image is about 30 meters. North is at the top of the photo. ESO PR Photo 24d/99 ESO PR Photo 24d/99 [Preview - JPEG: 400 x 381 pix - 108k] [Normal - JPEG: 800 x 762 pix - 240k] [High-Res - JPEG: 2300 x 2191 pix - 984k] Caption to ESO PR Photo 24d/99 : Geographical map with the sites of the VLT and ALMA indicated. ESO PR Photo 24e/99 ESO PR Photo 24e/99 [Preview - JPEG: 400 x 238 pix - 93k] [Normal - JPEG: 800 x 475 pix - 279k] [High-Res - JPEG: 2862 x 1701 pix - 4.2M] Caption to ESO PR Photo 24e/99 : Panoramic view of the proposed site for ALMA at Chajnantor. This high-altitude plain (elevation 5000 m) in the Chilean Andes mountains is an ideal site for ALMA. In this view towards the north, the Chajnantor mountain (5600 m) is in the foreground, left of the centre. The perfect cone of the Licancabur volcano (5900 m) on the Bolivian border is in the background further to the left. This image is a wide-angle composite (140° x 70°) of three photos (Hasselblad 6x6 with SWC 1:4.5/38 mm Biogon), obtained in December 1998. How to obtain ESO Press Information ESO Press Information is made available on the World-Wide Web (URL: http://www.eso.org../ ). ESO Press Photos may be reproduced, if credit is given to the European Southern Observatory.

Determination of particulate lead during MILAGRO / MCMA-2006 using Aerosol Mass Spectrometry

NASA Astrophysics Data System (ADS)

Salcedo, Dara; Onasch, T. B.; Aiken, A. C.; Williams, L. R.; de Foy, B.; Cubison, M. J.; Worsnop, D. R.; Molina, L. T.; Jimenez, J. L.

2010-05-01

We report the first measurements of particulate lead (Pb) from Aerodyne Aerosol Mass Spectrometers, which were deployed in and around Mexico City during the Megacity Initiative: Local and Global Research Observations (MILAGRO) / Mexico City Metropolitan Area 2006 (MCMA-2006) field campaigns. The high resolution mass spectrometer of one of the AMS instruments (HR-AMS) and the measured isotopic ratios unequivocally prove the detection of Pb in ambient particles. A substantial fraction of the lead evaporated slowly from the vaporizer of the instruments, which is indicative of species with low volatility at 600oC. A model was developed in order to estimate the ambient particulate Pb entering the AMS from the signals in the "open" and the "closed" (or "background") mass spectrum modes of the AMS. The model suggests the presence of at least two lead fractions with ~25% of the Pb signal exhibiting rapid evaporation (1/e decay constant, τ < 0.1 s) and ~75% exhibiting slow evaporation (τ ~2.4 min) at T0 and a different fraction (70% prompt and 30% slow evaporation) at a site northwest from the metropolitan area (PEMEX32 site). From laboratory experiments with pure Pb(NO3)2 particles, we estimated that the Pb ionization efficiency relative to nitrate (RIEPb) is 0.5. Comparison of time series of AMS Pb with other measurements carried out at the T0 urban supersite during MILAGRO (using Proton Induced X-ray Emission (PIXE), Inductively-Coupled Plasma Mass Spectrometry (ICP-MS) and single-particle counts from an Aerosol Time-of-Fight Mass Spectrometer (ATOFMS)) shows similar levels (for PIXE and ICP-MS) and substantial correlation. During part of the campaign, sampling at T0 was alternated every 10 minutes with an Aerosol Concentrator, which enabled the detection of signals for PbCl+ and PbS+ ions. PbS+ displays the signature of a slowly evaporating species, while PbCl+ appears to arise only from fast evaporation, which is likely due to the higher vapor pressure of the compounds generating PbCl+. This is consistent with the evaporation model results. Levels of particulate Pb measured during MILAGRO at T0 were similar to previous studies in Mexico City. Pb shows a diurnal cycle with a maximum in the early morning, which is typical of primary urban pollutants. Pb shows correlation with Zn, consistent with previous studies, while the sources of Pb appear to be at least partially disjoint from those of particulate chloride. Back trajectory analysis of the T0 Pb data suggests the presence of sources inside the urban area SSW and N of T0, with different chemical forms of Pb being associated with different source locations. High signals due to particulate lead were also detected in the PEMEX site; again, no correlation between Pb and chloride plumes was observed, suggesting mostly different sources for both species.

Determination of particulate lead during MILAGRO/MCMA-2006 using Aerosol Mass Spectrometry

NASA Astrophysics Data System (ADS)

Salcedo, D.; Onasch, T. B.; Aiken, A. C.; Williams, L. R.; de Foy, B.; Cubison, M. J.; Worsnop, D. R.; Molina, L. T.; Jimenez, J. L.

2010-02-01

We report the first measurements of particulate lead (Pb) from Aerodyne Aerosol Mass Spectrometers, which were deployed in and around Mexico City during the Megacity Initiative: Local and Global Research Observations (MILAGRO)/Mexico City Metropolitan Area 2006 (MCMA-2006) field campaigns. The high resolution mass spectrometer of one of the AMS instruments (HR-AMS) and the measured isotopic ratios unequivocally prove the detection of Pb in ambient particles. A substantial fraction of the lead evaporated slowly from the vaporizer of the instruments, which is indicative of species with low volatility at 600 °C. A model was developed in order to estimate the ambient particulate Pb entering the AMS from the signals in the "open" and the "closed" (or "background") mass spectrum modes of the AMS. The model suggests the presence of at least two lead fractions with ~25% of the Pb signal exhibiting rapid evaporation (1/e decay constant, τ<0.1 s) and ~75% exhibiting slow evaporation (τ~2.4 min) at the T0 urban supersite and a different fraction (70% prompt and 30% slow evaporation) at a site northwest from the metropolitan area (PEMEX site). From laboratory experiments with pure Pb(NO3)2 particles, we estimated that the Pb ionization efficiency relative to nitrate (RIEPb) is 0.5. Comparison of time series of AMS Pb with other measurements carried out at T0 (using Proton Induced X-ray Emission (PIXE), Inductively-Coupled Plasma Mass Spectrometry (ICP-MS) and single-particle counts from an Aerosol Time-of-Fight Mass Spectrometer (ATOFMS)) shows similar levels (for PIXE and ICP-MS) and substantial correlation. During part of the campaign, sampling at T0 was alternated every 10 min with an Aerosol Concentrator, which enabled the detection of signals for PbCl+ and PbS+ ions. PbS+ displays the signature of a slowly evaporating species, while PbCl+ appears to arise only from fast evaporation, which is likely due to the higher vapor pressure of the compounds generating PbCl+. This is consistent with the evaporation model results. Levels of particulate Pb measured at T0 were similar to previous studies in Mexico City. Pb shows a diurnal cycle with a maximum in the early morning, which is typical of primary urban pollutants. Pb shows correlation with Zn, consistent with previous studies, while the sources of Pb appear to be at least partially disjoint from those of particulate chloride. Back trajectory analysis of the T0 Pb data suggests the presence of sources inside the urban area SSW and N of T0, with different chemical forms of Pb being associated with different source locations. High signals due to particulate lead were also detected in the PEMEX site; again, no correlation between Pb and chloride plumes was observed, suggesting mostly different sources for both species.

Determination of particulate lead using aerosol mass spectrometry: MILAGRO/MCMA-2006 observations

NASA Astrophysics Data System (ADS)

Salcedo, D.; Onasch, T. B.; Aiken, A. C.; Williams, L. R.; de Foy, B.; Cubison, M. J.; Worsnop, D. R.; Molina, L. T.; Jimenez, J. L.

2010-06-01

We report the first measurements of particulate lead (Pb) from Aerodyne Aerosol Mass Spectrometers, which were deployed in and around Mexico City during the Megacity Initiative: Local and Global Research Observations (MILAGRO)/Mexico City Metropolitan Area 2006 (MCMA-2006) field campaigns. The high resolution mass spectrometer of one of the AMS instruments (HR-AMS) and the measured isotopic ratios unequivocally prove the detection of Pb in ambient particles. A substantial fraction of the lead evaporated slowly from the vaporizer of the instruments, which is indicative of species with low volatility at 600 °C. A model was developed in order to estimate the ambient particulate Pb entering the AMS from the signals in the "open" and the "closed" (or "background") mass spectrum modes of the AMS. The model suggests the presence of at least two lead fractions with ~25% of the Pb signal exhibiting rapid evaporation (1/e decay constant, τ<0.1 s) and ~75% exhibiting slow evaporation (τ~2.4 min) at the T0 urban supersite and a different fraction (70% prompt and 30% slow evaporation) at a site northwest from the metropolitan area (PEMEX site). From laboratory experiments with pure Pb(NO3)2 particles, we estimated that the Pb ionization efficiency relative to nitrate (RIEPb) is 0.5. Comparison of time series of AMS Pb with other measurements carried out at the T0 supersite during MILAGRO (using Proton Induced X-ray Emission (PIXE), Inductively-Coupled Plasma Mass Spectrometry (ICP-MS) and single-particle counts from an Aerosol Time-of-Fight Mass Spectrometer (ATOFMS)) shows similar levels (for PIXE and ICP-MS) and substantial correlation. During part of the campaign, sampling at T0 was alternated every 10 min with an Aerosol Concentrator, which enabled the detection of signals for PbCl+ and PbS+ ions. PbS+ displays the signature of a slowly evaporating species, while PbCl+ appears to arise only from fast evaporation, which is likely due to the higher vapor pressure of the compounds generating PbCl+. This is consistent with the evaporation model results. Levels of particulate Pb measured at T0 were similar to previous studies in Mexico City. Pb shows a diurnal cycle with a maximum in the early morning, which is typical of primary urban pollutants. Pb shows correlation with Zn, consistent with previous studies, while the sources of Pb appear to be at least partially disjoint from those of particulate chloride. Back trajectory analysis of the T0 Pb data suggests the presence of sources inside the urban area SSW and N of T0, with different chemical forms of Pb being associated with different source locations. High signals due to particulate lead were also detected in the PEMEX site; again, no correlation between Pb and chloride plumes was observed, suggesting mostly different sources for both species.

Using Computers for Intervention and Remediation of Severely Reading-Impaired Children in a University Literacy Clinic.

ERIC Educational Resources Information Center

Balajthy, Ernest; Reuber, Kristin; Damon, Corrine J.

A study investigated software choices of graduate-level clinicians in a university reading clinic to determine computer use and effectiveness in literacy instruction. The clinic involved students of varying ability, ages 7-12, using 24 Power Macintosh computers equipped with "ClarisWorks,""Kid Pix,""Student Writing…

Misc Tandem Pix

Science.gov Websites

looking east.jpg 183 KB UNIS Ion Source 111 KB MP-7 Low Energy.jpg 138 KB MP-7 Object West.jpg 117 KB MP-7 Object Middle.jpg 120 KB MP-7 Object East.jpg 142 KB MP-7 Image.jpg 151 KB SEU area in TR-4 looking

Environmentally-induced discharge transient coupling to spacecraft

NASA Technical Reports Server (NTRS)

Viswanathan, R.; Barbay, G.; Stevens, N. J.

1985-01-01

The Hughes SCREENS (Space Craft Response to Environments of Space) technique was applied to generic spin and 3-axis stabilized spacecraft models. It involved the NASCAP modeling for surface charging and lumped element modeling for transients coupling into a spacecraft. A differential voltage between antenna and spun shelf of approx. 400 V and current of 12 A resulted from discharge at antenna for the spinner and approx. 3 kv and 0.3 A from a discharge at solar panels for the 3-axis stabilized Spacecraft. A typical interface circuit response was analyzed to show that the transients would couple into the Spacecraft System through ground points, which are most vulnerable. A compilation and review was performed on 15 years of available data from electron and ion current collection phenomena. Empirical models were developed to match data and compared with flight data of Pix-1 and Pix-2 mission. It was found that large space power systems would float negative and discharge if operated at or above 300 V. Several recommendations are given to improve the models and to apply them to large space systems.

A /sup 1/Pi--X /sup 1/. sigma. /sup +/ band system in CH/sup +/ and CD/sup +/: theoretical spectroscopic constants and lifetimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elander, N.; Oddershede, J.; Beebe, N.H.F.

1977-08-15

Polarization propagator calculation of spectroscopic constants and radiative lifetimes for the A /sup 1/Pi--X /sup 1/..sigma../sup +/ band system are presented. The spectroscopic constants agree well with experimental and other theoretical values. We have also performed an iterative Rydberg-Klein-Rees (RKR) calculation of B/sub e/, ..omega../sub e/, and ..omega../sub e/x/sub e/ for the experimental X /sup 1/..sigma../sup +/ state.The calculated radiative lifetime for the A /sup 1/Pi state (v'=0) is 660 ns and 598 ns, with theoretical and experimental potential energy curves, respectively. This difference (about 60 ns) indicates the inaccuracy in the present calculation. Experimentally the most recent estimate ofmore » the A /sup 1/Pi (v'=0) state is 630 +- 50 ns, and theoretically the Yoshimine et al. transition moment gives tau (A /sup 1/Pi, v'=0) =722 ns.The radiative lifetimes calculated for CD/sup +/ are between 1.3% and 3.9% larger than the corresponding CH/sup +/ lifetimes.« less

Biotechnological potential of Azolla filiculoides for biosorption of Cs and Sr: Application of micro-PIXE for measurement of biosorption.

PubMed

Ghorbanzadeh Mashkani, Saeid; Tajer Mohammad Ghazvini, Parisa

2009-03-01

The presence of Cs and Sr in culture medium of Azolla filiculoides caused about 27.4% and 46.3% inhibition of biomass growth, respectively, in comparison to A. filiculoides control weight which had not metals. Biosorption batch experiments were conducted to determine the Cs and Sr binding ability of native biomass and chemically modified biosorbents derived from Azolla namely ferrocyanide Azolla sorbents type 1 and type 2 (FAS1 and FAS2) and hydrogen peroxide Azolla sorbent (HAS). The best Cs and Sr removal results were obtained when A. filiculoides was treated by 2M MgCl(2) and 30ml H(2)O(2) 8mM at pH 7 for 12h and it was then washed by NaOH solution at pH 10.5 for 6h. Pretreatment of Azolla have been suggested to modify the surface characteristics which could improve biosorption process. The binding of Cs and Sr on the cell wall of Azolla was studied with micro-PIXE and FT-IR.