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.

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.

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.

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.

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.

Enzymes immobilized in mesoporous silica: a physical-chemical perspective.

PubMed

Carlsson, Nils; Gustafsson, Hanna; Thörn, Christian; Olsson, Lisbeth; Holmberg, Krister; Åkerman, Björn

2014-03-01

Mesoporous materials as support for immobilized enzymes have been explored extensively during the last two decades, primarily not only for biocatalysis applications, but also for biosensing, biofuels and enzyme-controlled drug delivery. The activity of the immobilized enzymes inside the pores is often different compared to that of the free enzymes, and an important challenge is to understand how the immobilization affects the enzymes in order to design immobilization conditions that lead to optimal enzyme activity. This review summarizes methods that can be used to understand how material properties can be linked to changes in enzyme activity. Real-time monitoring of the immobilization process and techniques that demonstrate that the enzymes are located inside the pores is discussed by contrasting them to the common practice of indirectly measuring the depletion of the protein concentration or enzyme activity in the surrounding bulk phase. We propose that pore filling (pore volume fraction occupied by proteins) is the best standard for comparing the amount of immobilized enzymes at the molecular level, and present equations to calculate pore filling from the more commonly reported immobilized mass. Methods to detect changes in enzyme structure upon immobilization and to study the microenvironment inside the pores are discussed in detail. Combining the knowledge generated from these methodologies should aid in rationally designing biocatalyst based on enzymes immobilized in mesoporous materials. © 2013 Elsevier B.V. All rights reserved.

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.

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.

Stability studies of immobilized lipase on rice husk and eggshell membrane

NASA Astrophysics Data System (ADS)

Abdulla, R.; Sanny, S. A.; Derman, E.

2017-06-01

Lipase immobilization for biodiesel production is gaining importance day by day. In this study, lipase from Burkholderia cepacia was immobilized on activated support materials namely rice husk and egg shell membrane. Both rice husk and eggshell membrane are natural wastes that holds a lot of potential as immobilization matrix. Rice husk and eggshell membrane were activated with glutaraldehyde. Lipase was immobilized on the glutaraldehyde-activated support material through adsorption. Immobilization efficiency together with enzyme activity was observed to choose the highest enzyme loading for further stability studies. Immobilization efficiency of lipase on rice husk was 81 as compared to an immobilization efficiency of 87 on eggshell membrane. Immobilized lipase on eggshell membrane exhibited higher enzyme activity as compared to immobilized lipase on rice husk. Eggshell membrane also reported higher stability than rice husk as immobilization matrix. Both types of immobilized lipase retatined its activity after ten cycles of reuse. In short, eggshell membrane showed to be a better immobilization platform for lipase as compared to rice husk. However, with further improvement in technique of immobilization, the stability of both types of immobilized lipase can be improved to a greater extent.

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.

Standardisation of the ion beam facility at Chandigarh cyclotron for simultaneous PIXE and PESA analysis

NASA Astrophysics Data System (ADS)

Verma, Shivcharan; Mohanty, Biraja P.; Singh, Karn P.; Kumar, Ashok

2018-02-01

The proton beam facility at variable energy cyclotron (VEC) Panjab University, Chandigarh, India is being used for Particle Induced X-ray Emission (PIXE) analysis of different environmental, biological and industrial samples. The PIXE method, however, does not provide any information of low Z elements like carbon, nitrogen, oxygen and fluorine. As a result of the increased need for rapid and multi-elemental analysis of biological and environmental samples, the PIXE facility was upgraded and standardized to facilitate simultaneous measurements using PIXE and Proton Elastic Scattering Analysis (PESA). Both PIXE and PESA techniques were calibrated and standardized individually. Finally, the set up was tested by carrying out simultaneous PIXE and PESA measurements using a 2 mm diameter proton beam of 2.7 MeV on few multilayered thin samples. The results obtained show excellent agreement between PIXE and PESA measurements and confirm adequate sensitivity and precision of the experimental set up.

The Treatment of Snake Bites in a First Aid Setting: A Systematic Review.

PubMed

Avau, Bert; Borra, Vere; Vandekerckhove, Philippe; De Buck, Emmy

2016-10-01

The worldwide burden of snakebite is high, especially in remote regions with lesser accessibility to professional healthcare. Therefore, adequate first aid for snakebite is of the utmost importance. A wide range of different first aid techniques have been described in literature, and are being used in practice. This systematic review aimed to summarize the best available evidence concerning effective and feasible first aid techniques for snakebite. A systematic literature screening, performed independently by two authors in the Cochrane Library, MEDLINE and Embase resulted in 14 studies, fulfilling our predefined selection criteria, concerning first aid techniques for snakebite management. Data was extracted and the body of evidence was appraised according to the GRADE approach. The pressure immobilization technique was identified as the only evidence-based first aid technique with effectiveness on venom spread. However, additional studies suggest that proper application of this technique is not feasible for laypeople. Evidence concerning other first aid measures, such as the application of a tourniquet, suggests avoiding the use of these techniques. The practical recommendation for the treatment of snakebite in a first aid setting is to immobilize the victim, while awaiting the emergency services. However, given the low to very low quality of the data collected, high quality randomized controlled trials concerning the efficacy and feasibility of different variations of the pressure immobilization technique are warranted.

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.

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.

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

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

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

Theoretical detection limit of PIXE analysis using 20 MeV proton beams

NASA Astrophysics Data System (ADS)

Ishii, Keizo; Hitomi, Keitaro

2018-02-01

Particle-induced X-ray emission (PIXE) analysis is usually performed using proton beams with energies in the range 2∼3 MeV because at these energies, the detection limit is low. The detection limit of PIXE analysis depends on the X-ray production cross-section, the continuous background of the PIXE spectrum and the experimental parameters such as the beam currents and the solid angle and detector efficiency of X-ray detector. Though the continuous background increases as the projectile energy increases, the cross-section of the X-ray increases as well. Therefore, the detection limit of high energy proton PIXE is not expected to increase significantly. We calculated the cross sections of continuous X-rays produced in several bremsstrahlung processes and estimated the detection limit of a 20 MeV proton PIXE analysis by modelling the Compton tail of the γ-rays produced in the nuclear reactions, and the escape effect on the secondary electron bremsstrahlung. We found that the Compton tail does not affect the detection limit when a thin X-ray detector is used, but the secondary electron bremsstrahlung escape effect does have an impact. We also confirmed that the detection limit of the PIXE analysis, when used with 4 μm polyethylene backing film and an integrated beam current of 1 μC, is 0.4∼2.0 ppm for proton energies in the range 10∼30 MeV and elements with Z = 16-90. This result demonstrates the usefulness of several 10 MeV cyclotrons for performing PIXE analysis. Cyclotrons with these properties are currently installed in positron emission tomography (PET) centers.

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.

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.

Preliminary studies on immobilization of lipase using chicken eggshell

NASA Astrophysics Data System (ADS)

Salleh, S.; Serri, N. A.; Hena, S.; Tajarudin, H. A.

2016-06-01

A few advantages of enzyme immobilization are reusability of expensive enzyme, improvement of stability and activity compared to crude enzyme. Various organic components can be used as carrier for enzyme immobilization such as chicken eggshell. It can be used as a carrier for immobilization as its mineral component mostly contains of calcium carbonate. In the present study, Tributyrin method was used to test enzyme activity of Rhizomucour Miehei, Candida Antarctica and Candida Rugosa. Rhizomucour Miehei shows the highest enzyme activity (360.8 mol/min/mL lipase) and was used in further experiment. Experiment was continued to study incubation time for lipase immobilization on eggshell (1-4 hours) and reaction time of esterification of sugar ester (0-72 hours). Two hours incubation time for lipase immobilization was observed and gives the highest yield of sugar ester (78.13%). Fructose and stearic acid as substrate was used for the production of sugar ester. The highest percentage of sugar ester production was shown at 36 hours of reaction time.

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.

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

Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart.

PubMed

Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

2016-02-02

A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4-9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. © 2016 Authors.

Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart

PubMed Central

Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

2016-01-01

A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4–9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. PMID:26839417

PIXE Analysis of Indoor Aerosols

NASA Astrophysics Data System (ADS)

Johnson, Christopher; Turley, Colin; Moore, Robert; Battaglia, Maria; Labrake, Scott; Vineyard, Michael

2011-10-01

We have performed a proton-induced X-ray emission (PIXE) analysis of aerosol samples collected in academic buildings at Union College to investigate the air quality in these buildings and the effectiveness of their air filtration systems. This is also the commissioning experiment for a new scattering chamber in the Union College Ion-Beam Analysis Laboratory. The aerosol samples were collected on Kapton foils using a nine-stage cascade impactor that separates particles according to their aerodynamic size. The foils were bombarded with beams of 2.2-MeV protons from the Union College 1.1-MV Pelletron Accelerator and the X-ray products were detected with an Amptek silicon drift detector. After subtracting the contribution from the Kapton foils, the X-ray energy spectra of the aerosol samples were analyzed using GUPIX software to determine the elemental concentrations of the samples. We will describe the collection of the aerosol samples, discuss the PIXE analysis, and present the results.

PIXE Analysis of Atmospheric Aerosol Samples Collected in the Adirondack Mountains

NASA Astrophysics Data System (ADS)

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

2013-10-01

We have performed an elemental analysis of atmospheric aerosol 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 samples and distribute the particulate matter onto Kapton foils by particle size. The PIXE experiments were performed with 2.2-MeV proton beams from the 1.1-MV pelletron accelerator in the Union College Ion-Beam Analysis Laboratory. X-Ray energy spectra were measured with a silicon drift detector and analyzed with GUPIX software to determine the elemental concentrations of the aerosols. A broad range of elements from silicon to zinc were detected with significant sulfur concentrations measured for particulate matter between 0.25 and 0.5 μm in size. The PIXE analysis will be described and preliminary results will be presented.

Light transfer in agar immobilized microalgae cell cultures

NASA Astrophysics Data System (ADS)

Kandilian, Razmig; Jesus, Bruno; Legrand, Jack; Pilon, Laurent; Pruvost, Jérémy

2017-09-01

This paper experimentally and theoretically investigates light transfer in agar-immobilized cell cultures. Certain biotechnological applications such as production of metabolites secreted by photosynthetic microorganisms require cells to be immobilized in biopolymers to minimize contamination and to facilitate metabolite recovery. In such applications, light absorption by cells is one of the most important parameters affecting cell growth or metabolite productivity. Modeling light transfer therein can aid design and optimize immobilized-cell reactors. In this study, Parachlorella kessleri cells with areal biomass concentrations ranging from 0.36 to 16.9 g/m2 were immobilized in 2.6 mm thick agar gels. The average absorption and scattering cross-sections as well as the scattering phase function of P. kessleri cells were measured. Then, the absorption and transport scattering coefficients of the agar gel were determined using an inverse method based on the modified two-flux approximation. The forward model was used to predict the normal-hemispherical transmittance and reflectance of the immobilized-cell films accounting for absorption and scattering by both microalgae and the agar gel. Good agreement was found between the measured and predicted normal-hemispherical transmittance and reflectance provided absorption and scattering by agar were taken into account. Moreover, good agreement was found between experimentally measured and predicted mean rate of photon absorption. Finally, optimal areal biomass concentration was determined to achieve complete absorption of the incident radiation.

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.

PIXE study of the kinetics of biomaterials ossification

NASA Astrophysics Data System (ADS)

Weber, G.; Robaye, G.; Braye, F.; Oudadesse, H.; Irigaray, J. L.

1994-05-01

Biomaterials are frequently implanted in bones. This implantation is followed by a phenomenon of ossification. The purpose of this work was to study the time evolution of the gradient of characteristic atomic element's concentrations in the bone, the implant and the bone-implant interface. We have studied two types of neutral biomaterials: pure synthetic hydroxyapatite and porite's asteroid coral. The animal implantations have been made on sheep of the same age and sex having received the same basic diet. The implantations have been made in the cortical femur. On both sides of the implant, at the same distance, two screws were placed to allow further determination of the position of the implant. The PIXE method is particularly suitable here because of the possibility to analyze directly the samples without any preparation and to choose easily the dimensions of beam used for the gradient study. The X-rays have been detected with an ultra LEGe instead of the usual Si(Li) device to avoid the Si escape peak associated with the K α X-ray of calcium, the major constituent of bone. This peak is particularly disturbing here because its energy corresponds to the K α line of phosphorus, an important constituent of bone. The results of these determinations are presented and discussed.

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.

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.

Chemical speciation using high energy resolution PIXE spectroscopy in the tender X-ray range

NASA Astrophysics Data System (ADS)

Kavčič, Matjaž; Petric, Marko; Vogel-Mikuš, Katarina

2018-02-01

High energy resolution X-ray emission spectroscopy employing wavelength dispersive (WDS) crystal spectrometers can provide energy resolution on the level of core-hole lifetime broadening of the characteristic emission lines. While crystal spectrometers have been traditionally used in combination with electron excitation for major and minor element analysis, they have been rarely considered in proton induced X-ray emission (PIXE) trace element analysis mainly due to low detection efficiency. Compared to the simplest flat crystal WDS spectrometer the efficiency can be improved by employing cylindrically or even spherically curved crystals in combination with position sensitive X-ray detectors. When such spectrometer is coupled to MeV proton excitation, chemical bonding effects are revealed in the high energy resolution spectra yielding opportunity to extend the analytical capabilities of PIXE technique also towards chemical state analysis. In this contribution we will focus on the high energy resolution PIXE (HR-PIXE) spectroscopy in the tender X-ray range performed in our laboratory with our home-built tender X-ray emission spectrometer. Some general properties of high energy resolution PIXE spectroscopy in the tender X-ray range are presented followed by an example of sulfur speciation in biological tissue illustrating the capabilities as well as limitations of HR-PIXE method used for chemical speciation in the tender X-ray range.

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.

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.

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

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.

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.

Enzyme nanoparticle fabrication: magnetic nanoparticle synthesis and enzyme immobilization.

PubMed

Johnson, Patrick A; Park, Hee Joon; Driscoll, Ashley J

2011-01-01

Immobilized enzymes are drawing significant attention for potential commercial applications as biocatalysts by reducing operational expenses and by increasing process utilization of the enzymes. Typically, immobilized enzymes have greater thermal and operational stability at various pH values, ionic strengths and are more resistant to denaturation that the soluble native form of the enzyme. Also, immobilized enzymes can be recycled by utilizing the physical or chemical properties of the supporting material. Magnetic nanoparticles provide advantages as the supporting material for immobilized enzymes over competing materials such as: higher surface area that allows for greater enzyme loading, lower mass transfer resistance, less fouling effect, and selective, nonchemical separation from the reaction mixture by an applied a magnetic field. Various surface modifications of magnetic nanoparticles, such as silanization, carbodiimide activation, and PEG or PVA spacing, aid in the binding of single or multienzyme systems to the particles, while cross-linking using glutaraldehyde can also stabilize the attached enzymes.

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.

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.

Comperative study of catalase immobilization on chitosan, magnetic chitosan and chitosan-clay composite beads.

PubMed

Başak, Esra; Aydemir, Tülin; Dinçer, Ayşe; Becerik, Seda Çınar

2013-12-01

Catalase was immobilized on chitosan and modified chitosan. Studies were carried out on free-immobilized catalase concerning the determination of optimum temperature, pH, thermal, storage stability, reusability, and kinetic parameters. Optimum temperature and pH for free catalase and catalase immobilized were found as 35°C and 7.0, respectively. After 100 times of repeated tests, the immobilized catalases on chitosan-clay and magnetic chitosan maintain over 50% and 60% of the original activity, respectively. The ease of catalase immobilization on low-cost matrices and good stability upon immobilization in the present study make it a suitable product for further use in the food industry.

Trace elements in human alveolar macrophages studied by PIXE

NASA Astrophysics Data System (ADS)

Weber, G.; Roelandts, I.; Corhay, J. L.; Radermecker, M.; Delavignette, J. P.

1990-04-01

The purpose of this study is to determine the metal content of alveolar macrophages by PIXE from 94 subjects divided into two groups as follows: group (1) — subjects with non-occupational exposure to industrial dust: 30 healthy volunteers (controls), 16 patients suffering from lung cancer; group (2) — 48 healthy steel workers from the Liège area (blast-furnace [ n=29] and coke oven [ n=19]). We hope to define more precisely the influence of carcinoma, smoking habit, pathology and occupational exposure in the steel industry on the macrophage metal content. This study has shown: (a) an Fe and Sr increase and a Br decrease in the macrophages of smokers (especially in heavy smokers): (b) a significant Fe, Ti, Br and Cu increase and a trend to Pb, Cr, As and Sr increase in macrophages of healthy steel workers (especially blast-furnace workers) in comparison with non-exposed controls; (c) a significant Fe, Br, Cu and Zn increase and a trend to Pb, As and Ni increase in macrophages of non-exposed patients with lung cancer by comparison with non-exposed controls. The mechanism of metal change could be explained by professional exposure and endogenous changes (protein synthesis, inflammation, bronchial bleeding, …)

External-PIXE analysis for the study of pigments from a painting from the Museum of Contemporary Art

NASA Astrophysics Data System (ADS)

Rizzutto, M. A.; Moro, M. V.; Silva, T. F.; Trindade, G. F.; Added, N.; Tabacniks, M. H.; Kajiya, E. M.; Campos, P. H. V.; Magalhães, A. G.; Barbosa, M.

2014-08-01

External Ion Beam Analysis is a useful tool for the characterization of cultural heritage objects. During the last decade, several significant collaborations have been established between Ion Beam Analysis (IBA) scientists and art or archeology professionals, demanding in-air IBA for a variety of different cultural heritage objects. In-air Particle Induced X-ray Emission (PIXE) analyses of an oil painting by the Italian painter, Mario Sironi, from the Museum of Contemporary Art of the University of São Paulo (MAC-USP), were examined. This painting is particularly interesting due to paintings on both sides (oil on canvas on the front and oil on wood on the back side). PIXE analysis helped the identification of the pigment similarities on both sides of the painting, suggesting the same authorship.

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.

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.

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.

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.

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.

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.

Effects of the immobilization supports on the catalytic properties of immobilized mushroom tyrosinase: a comparative study using several substrates.

PubMed

Marín-Zamora, María Elisa; Rojas-Melgarejo, Francisco; García-Cánovas, Francisco; García-Ruiz, Pedro Antonio

2007-09-30

Mushroom tyrosinase was immobilized from an extract onto glass beads covered with one of the following compounds: the crosslinked totally cinnamoylated derivatives of glycerine, D-sorbitol, D-manitol, 1,2-O-isopropylidene-alpha-D-glucofuranose, D-glucuronic acid, D-gulonic acid, sucrose, D-glucosone, D-arabinose, D-fructose, D-glucose, ethyl-D-glucopyranoside, inuline, dextrine, dextrane or starch, or the partially cinnamoylated derivative 3,5,6-tricinnamoyl-D-glucofuranose which was obtained by the acid hydrolysis of 1,2-O-isopropylidene-alpha-d-glucofuranose. The enzyme was immobilized by direct adsorption onto the support and the quantity of tyrosinase immobilized was found to increase with the hydrophobicity of the supports. The kinetic constants of immobilized tyrosinase acting on the substrates, 4-tert-butylcatechol, dopamine and DL-dopa, were studied. When immobilized tyrosinase acted on 4-tert-butylcatechol, the values of K(m)(app) were lower than these obtained for tyrosinase in solution while, when dopamine and DL-dopa were used, the K(m)(app) were higher. The order of the substrates as regards their ionizable groups, DL-dopa (two ionizable groups)>dopamine (one ionizable group)>4-tert-butylcatechol (no ionizable group) coincided with the order of the K(m)(app) values shown by tyrosinase immobilized on the hydrophobic supports, and was the inverse of that observed for tyrosinase in solution. The K(m)(app) values of immobilized tyrosinase were in all cases higher than those of soluble tyrosinase and depended on the nature of the support and the hydrophobicity of the substrate, meaning that it is possible to design supports with different degrees of selectivity towards a mixture of enzyme substrates in the reaction medium.

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.

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.

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.

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.

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.

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.

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.

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

. 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.

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.

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.

Artificial neural networks applied to quantitative elemental analysis of organic material using PIXE

NASA Astrophysics Data System (ADS)

Correa, R.; Chesta, M. A.; Morales, J. R.; Dinator, M. I.; Requena, I.; Vila, I.

2006-08-01

An artificial neural network (ANN) has been trained with real-sample PIXE (particle X-ray induced emission) spectra of organic substances. Following the training stage ANN was applied to a subset of similar samples thus obtaining the elemental concentrations in muscle, liver and gills of Cyprinus carpio. Concentrations obtained with the ANN method are in full agreement with results from one standard analytical procedure, showing the high potentiality of ANN in PIXE quantitative analyses.

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.

Experimental study on cesium immobilization in struvite structures.

PubMed

Wagh, Arun S; Sayenko, S Y; Shkuropatenko, V A; Tarasov, R V; Dykiy, M P; Svitlychniy, Y O; Virych, V D; Ulybkina, Е А

2016-01-25

Ceramicrete, a chemically bonded phosphate ceramic, was developed for nuclear waste immobilization and nuclear radiation shielding. Ceramicrete products are fabricated by an acid-base reaction between magnesium oxide and mono potassium phosphate that has a struvite-K mineral structure. In this study, we demonstrate that this crystalline structure is ideal for incorporating radioactive Cs into a Ceramicrete matrix. This is accomplished by partially replacing K by Cs in the struvite-K structure, thus forming struvite-(K, Cs) mineral. X-ray diffraction and thermo-gravimetric analyses are used to confirm such a replacement. The resulting product is non-leachable and stable at high temperatures, and hence it is an ideal matrix for immobilizing Cs found in high-activity nuclear waste streams. The product can also be used for immobilizing secondary waste streams generated during glass vitrification of spent fuel, or the method described in this article can be used as a pretreatment method during glass vitrification of high level radioactive waste streams. Furthermore, it suggests a method of producing safe commercial radioactive Cs sources. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

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.

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.

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.

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.

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 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.

CdTe and EDS HR-PIXE Ta L and M spectra induced by duoplasmatron generated proton and oxygen ion beams

NASA Astrophysics Data System (ADS)

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

2018-02-01

Particle induced X-ray emission (PIXE) is a powerful technique for quantitative analysis because it is non-destructive, multi-elemental (from Na to U), highly sensitive and requires no special sample preparation. Heavy Ions PIXE (HI-PIXE), may represent a further step in versatility but it comes with added complexity of the physical processes involved in X-ray production, which require among other things new software capabilities. In this work, the specific capacities of the DT2 code are used to simulate and fit Ta L- and M-shell spectra obtained during the irradiation of a Ta2O5 thin film deposited upon a polished vitreous graphite substrate, produced in the frame of the Heavy Ions PIXE workpakage of the IAEA Coordinated Research Project F11019 on analytical uses of MeV focused ion beams. Proton and oxygen beams from a duoplasmatron ion source were used, and spectra were collected using both the CdTe and the X-ray Microcalorimeter Spectrometer detectors of the High Resolution High X-ray Energy PIXE (HRHE-PIXE) facility of C2TN. Results obtained from the simulation and the fitting of these spectra are presented and discussed.

Follow-up of ankle stiffness and electromechanical delay in immobilized children: three cases studies.

PubMed

Grosset, Jean-François; Lapole, Thomas; Mora, Isabelle; Verhaeghe, Martine; Doutrellot, Pierre-Louis; Pérot, Chantal

2010-08-01

Clinical manual tests refer to increased ankle stiffness in children immobilized due to hip osteochondritis. The aim of the present study was to investigate musculo-articular stiffness via different techniques in immobilized children to confirm or not and quantify these observations. Ankle stiffness was quantified monthly during the long immobilization period in three diseased children and compared to healthy age-matched children. Sinusoidal perturbations were used to evaluate musculo-articular (MA) stiffness of the ankle plantar-flexors. The stiffness index (SI(MA-EMG)) was the slope of the linear relationship between angular stiffness and plantar-flexion torque normalized with electromyographic activity of the triceps surae (TS). The stiffness of the ankle plantar-flexors was also indirectly evaluated using the TS electromechanical delay (EMD). SI(MA-EMG) was greater for diseased children, and this higher stiffness was confirmed by the higher EMD values found in these immobilized children. Furthermore, both parameters indicated that ankle stiffness continues to increase through immobilization period. This study gives a quantitative evaluation of ankle stiffness changes through the immobilization period imposed to children treated for hip osteochondritis. The use of EMD measurement to indirectly evaluate these stiffness changes is also validated. This study shed for the first time some light into the patterns of muscle modifications following immobilization in children. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Enzyme Immobilization: An Overview on Methods, Support Material, and Applications of Immobilized Enzymes.

PubMed

Sirisha, V L; Jain, Ankita; Jain, Amita

Immobilized enzymes can be used in a wide range of processes. In recent years, a variety of new approaches have emerged for the immobilization of enzymes that have greater efficiency and wider usage. During the course of the last two decades, this area has rapidly expanded into a multidisciplinary field. This current study is a comprehensive review of a variety of literature produced on the different enzymes that have been immobilized on various supporting materials. These immobilized enzymes have a wide range of applications. These include applications in the sugar, fish, and wine industries, where they are used for removing organic compounds from waste water. This study also reviews their use in sophisticated biosensors for metabolite control and in situ measurements of environmental pollutants. Immobilized enzymes also find significant application in drug metabolism, biodiesel and antibiotic production, bioremediation, and the food industry. The widespread usage of immobilized enzymes is largely due to the fact that they are cheaper, environment friendly, and much easier to use when compared to equivalent technologies. © 2016 Elsevier Inc. All rights reserved.

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.

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.

Study on immobilization of marine oil-degrading bacteria by carrier of algae materials.

PubMed

Zhang, Yiran; Gao, Wei; Lin, Faxiang; Han, Bin; He, Changfei; Li, Qian; Gao, Xiangxing; Cui, Zhisong; Sun, Chengjun; Zheng, Li

2018-05-18

This study investigated the immobilizations with of bacteria two kinds of algal materials, Enteromorpha residue and kelp residue. The lipophilicity of them were compared by diesel absorption rates. The immobilization efficiency of Bacillus sp. E3 was measured to evaluate whether these carriers would satisfy the requirement for biodegradation of oil spills. The bacteria were immobilized through adsorption with the sterilized and non-sterilized carriers to compare the differences between the two treatments. Oil degradation rates were determined using gravimetric and GC-MS methods. Results showed the absorption rates of Enteromorpha residue and kelp residue for diesel were 411 and 273% respectively and remained approximately 105 and 120% after 2 h of erosion in simulated seawater system. After immobilized of Bacillus sp. E3, the oil degradation rates of them were higher than 65% after 21 days biodegradations. GC-MS analysis showed that two immobilizations degraded higher than 70% of the total alkane and the total PAHs, whereas the free bacteria degraded 63% of the total alkane and 66% the total PAHs. And the bacteria immobilized with the carriers degraded more HMW-alkanes and HMW-PAHs than the free bacteria. The bacteria immobilized by non-sterilized kelp residue showed a considerably higher degradation rate than that using sterilized kelp residue. A considerably higher cells absorption rate of immobilization was obtained when using kelp residue, and the preparation of immobilization was low cost and highly efficient. The experiments show the two algae materials, especially the kelp residue, present potential application in bioremediation of marine oil spills.

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.

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.

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

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

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.

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.

Study of bone mineral metabolism. [during body immobilization, bed rest, and space flight

NASA Technical Reports Server (NTRS)

Palmer, H. E.

1975-01-01

The use of Sr-85 as an indicator of the skeletal location and relative amount of bone demineralization which occurs during immobilization of the body or body parts, bed-rest or space flight was studied. The bone mineral replacement which occurs after immobilization was measured rather than the bone loss which occurs during immobilization. In a study with two adult beagle dogs, the Sr-85 uptake in a leg which had been immobilized for two months was 400 percent higher than the uptake in the legs in regular use. This increased uptake probably resulted from only a few percent loss in bone mineral and indicates that losses less than one percent can be easily detected and located. The sensitivity, simplicity, and low radiation dose associated with the use of this method indicates that it should receive consideration for use on humans in bed-rest and space flight studies. Methods for measuring changes in total body nitrogen and in assisting the Johnson Space Center in calibrating a whole body counter for total body potassium measurements were also investigated.

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.

Long-term C. elegans immobilization enables high resolution developmental studies in vivo.

PubMed

Berger, Simon; Lattmann, Evelyn; Aegerter-Wilmsen, Tinri; Hengartner, Michael; Hajnal, Alex; deMello, Andrew; Casadevall I Solvas, Xavier

2018-05-01

Live-imaging of C. elegans is essential for the study of conserved cellular pathways (e.g. EGFR/Wnt signaling) and morphogenesis in vivo. However, the usefulness of live imaging as a research tool has been severely limited by the need to immobilize worms prior to and during imaging. Conventionally, immobilization is achieved by employing both physical and chemical interventions. These are known to significantly affect many physiological processes, and thus limit our understanding of dynamic developmental processes. Herein we present a novel, easy-to-use microfluidic platform for the long-term immobilization of viable, normally developing C. elegans, compatible with image acquisition at high resolution, thereby overcoming the limitations associated with conventional worm immobilization. The capabilities of the platform are demonstrated through the continuous assessment of anchor cell (AC) invasion and distal tip cell (DTC) migration in larval C. elegans and germ cell apoptosis in adult C. elegans in vivo for the first time.

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.

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.

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.

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.

An efficient TiO2 coated immobilized system for the degradation studies of herbicide isoproturon: durability studies.

PubMed

Verma, A; Prakash, N T; Toor, A P

2014-08-01

The investigation presents the observations on the use of cement beads for the immobilization of TiO2 for the degradation of herbicide isoproturon. The immobilized system was effective in degrading and mineralizing the herbicide for continuous thirty cycles without losing its durability. Catalyst was characterized by SEM-EDAX for checking the durability of the catalyst. The degradation rate followed first order kinetics as measured by change in absorption intensity in UV range as well as HPLC analysis. Two rounds of TiO2 coating on inert cement beads with average diameter 1.5cm at UV Intensity 25Wm(-2) calcined at 400°C were the optimized conditions for the degradation of herbicide isoproturon. More than 90% TOC and COD reduction along with ammonium ions generation (80%) confirmed the mineralization of isoproturon. Fixed bed baffled reactor studies under solar irradiations using the TiO2 immobilized beads confirmed 85% degradation after 6h. LC-MS studies confirmed the intermediates formation and their subsequent degradation using immobilized system. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

Protein immobilization techniques for microfluidic assays

PubMed Central

Kim, Dohyun; Herr, Amy E.

2013-01-01

Microfluidic systems have shown unequivocal performance improvements over conventional bench-top assays across a range of performance metrics. For example, specific advances have been made in reagent consumption, throughput, integration of multiple assay steps, assay automation, and multiplexing capability. For heterogeneous systems, controlled immobilization of reactants is essential for reliable, sensitive detection of analytes. In most cases, protein immobilization densities are maximized, while native activity and conformation are maintained. Immobilization methods and chemistries vary significantly depending on immobilization surface, protein properties, and specific assay goals. In this review, we present trade-offs considerations for common immobilization surface materials. We overview immobilization methods and chemistries, and discuss studies exemplar of key approaches—here with a specific emphasis on immunoassays and enzymatic reactors. Recent “smart immobilization” methods including the use of light, electrochemical, thermal, and chemical stimuli to attach and detach proteins on demand with precise spatial control are highlighted. Spatially encoded protein immobilization using DNA hybridization for multiplexed assays and reversible protein immobilization surfaces for repeatable assay are introduced as immobilization methods. We also describe multifunctional surface coatings that can perform tasks that were, until recently, relegated to multiple functional coatings. We consider the microfluidics literature from 1997 to present and close with a perspective on future approaches to protein immobilization. PMID:24003344

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.

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.

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.

Study Guide for First Aid Practices.

ERIC Educational Resources Information Center

Thygerson, Alton L.

This study guide is designed to accompany the American National Red Cross texts ADVANCED FIRST AID AND EMERGENCY CARE and STANDARD FIRST AID AND PERSONAL SAFETY. Part one serves as an introduction to first aid. The legal aspects of first aid are discussed along with a list of suggested first aid kit contents, and information on first aid books is…

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 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.

Comparative study on antibody immobilization strategies for efficient circulating tumor cell capture.

PubMed

Ates, Hatice Ceren; Ozgur, Ebru; Kulah, Haluk

2018-03-23

Methods for isolation and quantification of circulating tumor cells (CTCs) are attracting more attention every day, as the data for their unprecedented clinical utility continue to grow. However, the challenge is that CTCs are extremely rare (as low as 1 in a billion of blood cells) and a highly sensitive and specific technology is required to isolate CTCs from blood cells. Methods utilizing microfluidic systems for immunoaffinity-based CTC capture are preferred, especially when purity is the prime requirement. However, antibody immobilization strategy significantly affects the efficiency of such systems. In this study, two covalent and two bioaffinity antibody immobilization methods were assessed with respect to their CTC capture efficiency and selectivity, using an anti-epithelial cell adhesion molecule (EpCAM) as the capture antibody. Surface functionalization was realized on plain SiO 2 surfaces, as well as in microfluidic channels. Surfaces functionalized with different antibody immobilization methods are physically and chemically characterized at each step of functionalization. MCF-7 breast cancer and CCRF-CEM acute lymphoblastic leukemia cell lines were used as EpCAM positive and negative cell models, respectively, to assess CTC capture efficiency and selectivity. Comparisons reveal that bioaffinity based antibody immobilization involving streptavidin attachment with glutaraldehyde linker gave the highest cell capture efficiency. On the other hand, a covalent antibody immobilization method involving direct antibody binding by N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC)-N-hydroxysuccinimide (NHS) reaction was found to be more time and cost efficient with a similar cell capture efficiency. All methods provided very high selectivity for CTCs with EpCAM expression. It was also demonstrated that antibody immobilization via EDC-NHS reaction in a microfluidic channel leads to high capture efficiency and selectivity.

Stability improvement of immobilized lactoperoxidase using polyaniline polymer.

PubMed

Jafary, Fariba; Kashanian, Soheila; Sharieat, Ziadin Samsam; Jafary, Farzaneh; Omidfar, Kobra; Paknejad, Maliheh

2012-12-01

Enzyme engineering via immobilization techniques is perfectly compatible against the other chemical or biological approximate to improve enzyme functions and stability. In this study lactoperoxidase was immobilized onto polyaniline polymer activated with glutaraldehyde as a bifunctional agent, to improve enzyme properties. Polyaniline polymer was used due its unique physical and chemical properties to immobilize lactoperoxidase (LPO). The optimum activity of immobilized LPO was observed at pH 6 and 55 °C, which has been increased about 10 °C for the immobilized enzyme. The immobilized enzyme maintained absolutely active for 60 days whereas the native enzyme lost 80 % of its initial activity within this period of time. Moreover, the immobilized enzyme can be reused for several times without loss of activity. The kinetic parameter studies showed slight differences between free and immobilized enzymes. The K(m) and K(m.app) were calculated to be 0.6 and 0.4; also V(max) and V(max.app) were 1.3 and 0.9 respectively.

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.

An overview of technologies for immobilization of enzymes and surface analysis techniques for immobilized enzymes

PubMed Central

Mohamad, Nur Royhaila; Marzuki, Nur Haziqah Che; Buang, Nor Aziah; Huyop, Fahrul; Wahab, Roswanira Abdul

2015-01-01

The current demands of sustainable green methodologies have increased the use of enzymatic technology in industrial processes. Employment of enzyme as biocatalysts offers the benefits of mild reaction conditions, biodegradability and catalytic efficiency. The harsh conditions of industrial processes, however, increase propensity of enzyme destabilization, shortening their industrial lifespan. Consequently, the technology of enzyme immobilization provides an effective means to circumvent these concerns by enhancing enzyme catalytic properties and also simplify downstream processing and improve operational stability. There are several techniques used to immobilize the enzymes onto supports which range from reversible physical adsorption and ionic linkages, to the irreversible stable covalent bonds. Such techniques produce immobilized enzymes of varying stability due to changes in the surface microenvironment and degree of multipoint attachment. Hence, it is mandatory to obtain information about the structure of the enzyme protein following interaction with the support surface as well as interactions of the enzymes with other proteins. Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes. These technologies are pertinent to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies. PMID:26019635

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.

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.

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).

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).

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.

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.

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.

Coprinus comatus Damages Nematode Cuticles Mechanically with Spiny Balls and Produces Potent Toxins To Immobilize Nematodes▿

PubMed Central

Luo, Hong; Liu, Yajun; Fang, Lin; Li, Xuan; Tang, Ninghua; Zhang, Keqin

2007-01-01

We reported recently a unique fungal structure, called the spiny ball, on the vegetative hyphae of Coprinus comatus (O. F. Müll.:Fr.) Pers. Although some observations regarding the role of this structure were presented, its function remained largely unknown. In this study, we showed that purified (isolated and washed) spiny balls could immobilize and kill the free-living nematode Panagrellus redivivus Goodey highly efficiently. Scanning electron microscopy studies illustrated that the spiny structure damaged the nematode cuticle, suggesting the presence of a mechanical force during the process of nematode immobilization. Severe injuries on nematode cuticles caused the leakage of inner materials of the nematodes. When these structures were ground in liquid nitrogen, their killing efficacy against nematodes was lost, indicating that the shape and the complete structure of the spiny balls are indispensable for their function. However, extraction with organic solvents never lowered their activity against P. redivivus, and the extracts showed no obvious effect on the nematode. We also investigated whether C. comatus was able to produce toxins which would aid in the immobilization of nematodes. In total, we identified seven toxins from C. comatus that showed activity to immobilize the nematodes P. redivivus and Meloidogyne incognita (Kofoid et White) Chitwood. The chemical structures of these toxins were identified with nuclear magnetic resonance, mass spectrometry, infrared, and UV spectrum analysis. Two compounds were found to be novel. The toxins found in C. comatus are O-containing heterocyclic compounds. PMID:17449690

Coprinus comatus damages nematode cuticles mechanically with spiny balls and produces potent toxins to immobilize nematodes.

PubMed

Luo, Hong; Liu, Yajun; Fang, Lin; Li, Xuan; Tang, Ninghua; Zhang, Keqin

2007-06-01

We reported recently a unique fungal structure, called the spiny ball, on the vegetative hyphae of Coprinus comatus (O. F. Müll.:Fr.) Pers. Although some observations regarding the role of this structure were presented, its function remained largely unknown. In this study, we showed that purified (isolated and washed) spiny balls could immobilize and kill the free-living nematode Panagrellus redivivus Goodey highly efficiently. Scanning electron microscopy studies illustrated that the spiny structure damaged the nematode cuticle, suggesting the presence of a mechanical force during the process of nematode immobilization. Severe injuries on nematode cuticles caused the leakage of inner materials of the nematodes. When these structures were ground in liquid nitrogen, their killing efficacy against nematodes was lost, indicating that the shape and the complete structure of the spiny balls are indispensable for their function. However, extraction with organic solvents never lowered their activity against P. redivivus, and the extracts showed no obvious effect on the nematode. We also investigated whether C. comatus was able to produce toxins which would aid in the immobilization of nematodes. In total, we identified seven toxins from C. comatus that showed activity to immobilize the nematodes P. redivivus and Meloidogyne incognita (Kofoid et White) Chitwood. The chemical structures of these toxins were identified with nuclear magnetic resonance, mass spectrometry, infrared, and UV spectrum analysis. Two compounds were found to be novel. The toxins found in C. comatus are O-containing heterocyclic compounds.

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.

Ceramic membrane microfilter as an immobilized enzyme reactor.

PubMed

Harrington, T J; Gainer, J L; Kirwan, D J

1992-10-01

This study investigated the use of a ceramic microfilter as an immobilized enzyme reactor. In this type of reactor, the substrate solution permeates the ceramic membrane and reacts with an enzyme that has been immobilized within its porous interior. The objective of this study was to examine the effect of permeation rate on the observed kinetic parameters for the immobilized enzyme in order to assess possible mass transfer influences or shear effects. Kinetic parameters were found to be independent of flow rate for immobilized penicillinase and lactate dehydrogenase. Therefore, neither mass transfer nor shear effects were observed for enzymes immobilized within the ceramic membrane. Both the residence time and the conversion in the microfilter reactor could be controlled simply by regulating the transmembrane pressure drop. This study suggests that a ceramic microfilter reactor can be a desirable alternative to a packed bed of porous particles, especially when an immobilized enzyme has high activity and a low Michaelis constant.

Functionalized Graphene Sheets As Immobilization Matrix for Fenugreek β-Amylase: Enzyme Kinetics and Stability Studies

PubMed Central

Srivastava, Garima; Singh, Kritika; Talat, Mahe; Srivastava, Onkar Nath; Kayastha, Arvind M.

2014-01-01

β-Amylase finds application in food and pharmaceutical industries. Functionalized graphene sheets were customised as a matrix for covalent immobilization of Fenugreek β-amylase using glutaraldehyde as a cross-linker. The factors affecting the process were optimized using Response Surface Methodology based Box-Behnken design of experiment which resulted in 84% immobilization efficiency. Scanning and Transmission Electron Microscopy (SEM, TEM) and Fourier Tansform Infrared (FTIR) spectroscopy were employed for the purpose of characterization of attachment of enzyme on the graphene. The enzyme kinetic studies were carried out for obtaining best catalytic performance and enhanced reusability. Optimum temperature remained unchanged, whereas optimum pH showed shift towards acidic range for immobilized enzyme. Increase in thermal stability of immobilized enzyme and non-toxic nature of functionalized graphene can be exploited for production of maltose in food and pharmaceutical industries. PMID:25412079

Efficient Production of Prebiotic Gluco-oligosaccharides in Orange Juice Using Immobilized and Co-immobilized Dextransucrase.

PubMed

Tingirikari, Jagan Mohan Rao; Gomes, Wesley Faria; Rodrigues, Sueli

2017-12-01

Dextransucrase from Leuconostoc mesenteroides NRRL B-512F was subjected to immobilization and co-immobilization with dextranase from Chaetomium erraticum. Immobilization has enhanced the operational and storage stability of dextransucrase. Two hundred milligrammes (2.4 IU/mg) of alginate beads (immobilized and co-immobilized) were found to be optimum for the production of gluco-oligosaccharides (GOS) in orange juice with a high degree of polymerization. The pulp of the orange juice did not interfere in the reaction. In the batch process, co-immobilized dextransucrase (41 g/L) produced a significantly higher amount of GOS than immobilized dextransucrase (37 g/L). Alginate entrapment enhanced the thermal stability of dextransucrase for up to 3 days in orange juice at 30 °C. The production of GOS in semi-continuous process was 39 g/L in co-immobilized dextransucrase and 33 g/L in immobilized dextransucrase. Thus, immobilization technology offers a great scope in terms of reusability and efficient production of a value added functional health drink.

Excess Weapons Plutonium Immobilization in Russia

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

Jardine, L.; Borisov, G.B.

2000-04-15

The joint goal of the Russian work is to establish a full-scale plutonium immobilization facility at a Russian industrial site by 2005. To achieve this requires that the necessary engineering and technical basis be developed in these Russian projects and the needed Russian approvals be obtained to conduct industrial-scale immobilization of plutonium-containing materials at a Russian industrial site by the 2005 date. This meeting and future work will provide the basis for joint decisions. Supporting R&D projects are being carried out at Russian Institutes that directly support the technical needs of Russian industrial sites to immobilize plutonium-containing materials. Special R&Dmore » on plutonium materials is also being carried out to support excess weapons disposition in Russia and the US, including nonproliferation studies of plutonium recovery from immobilization forms and accelerated radiation damage studies of the US-specified plutonium ceramic for immobilizing plutonium. This intriguing and extraordinary cooperation on certain aspects of the weapons plutonium problem is now progressing well and much work with plutonium has been completed in the past two years. Because much excellent and unique scientific and engineering technical work has now been completed in Russia in many aspects of plutonium immobilization, this meeting in St. Petersburg was both timely and necessary to summarize, review, and discuss these efforts among those who performed the actual work. The results of this meeting will help the US and Russia jointly define the future direction of the Russian plutonium immobilization program, and make it an even stronger and more integrated Russian program. The two objectives for the meeting were to: (1) Bring together the Russian organizations, experts, and managers performing the work into one place for four days to review and discuss their work with each other; and (2) Publish a meeting summary and a proceedings to compile reports of all the

Kinetic study of Candida antarctica lipase B immobilization using poly(methyl methacrylate) nanoparticles obtained by miniemulsion polymerization as support.

PubMed

Valério, Alexsandra; Nicoletti, Gabrieli; Cipolatti, Eliane P; Ninow, Jorge L; Araújo, Pedro H H; Sayer, Cláudia; de Oliveira, Débora

2015-03-01

With the objective to obtain immobilized Candida antarctica lipase B (CalB) with good activity and improved utilization rate, this study evaluated the influence of enzyme and crodamol concentrations and initiator type on the CalB enzyme immobilization in nanoparticles consisting of poly(methyl methacrylate) (PMMA) obtained by miniemulsion polymerization. The kinetic study of immobilized CalB enzyme in PMMA nanoparticles was evaluated in terms of monomer conversion, particle size, zeta potential, and relative activity. The optimum immobilization condition for CalB was compared with free enzyme in the p-NPL hydrolysis activity measurement. Results showed a higher CalB enzyme stability after 20 hydrolysis cycles compared with free CalB enzyme; in particular, the relative immobilized enzyme activity was maintained up to 40%. In conclusion, PMMA nanoparticles proved to be a good support for the CalB enzyme immobilization and may be used as a feasible alternative catalyst in industrial processes.

Micro-PIXE and micro-SR-XRF studies for Romanian archaeological gold identification

NASA Astrophysics Data System (ADS)

Constantinescu, B.

2009-04-01

For gold, trace elements are more significant for provenancing archaeological artifacts than the main components: Platinum Group Elements (PGE), Sn, Te, Sb, Hg, Pb, but also high melting point elements, such as Ta and Nb. Several small fragments of native Carpathian gold were studied using micro-PIXE technique at the AGLAE accelerator, Louvre Museum and at the Legnaro AN2000 microbeam facility, and using SR-XRF at BESSY synchrotron. The goal of the study was to identify the trace elements, especially Sn, Sb and Te. At BESSY, the SR-XRF measurements were performed in air by using a 34 keV beam to excite the characteristic X-lines in Sn-Sb-Te region. We found Sn to be present in placers from Valea Arieşului and Valea Pianului, Sb in primary gold from Zlatna, Ruda-Brad, Valea Morii, Runculeţ-Straja and Pb in primary gold from Brǎdişor-Brad, Zlatna, Runculeţ-Straja, Valea Morii, Muşariu-Brad. Ten native gold nuggets and several fragments of objects coming from Visigothic Pietroasa "The Golden Brood Hen with Its Chickens" hoard were analyzed using micro-PIXE technique at the AGLAE accelerator, Louvre Museum, Paris and at the Legnaro AN2000 microbeam facility. We found Te in primary gold from Brǎdişor-Brad, Muşariu-Brad (different samples from BESSY analyzed ones), and Roşia Montanǎ, Sb in primary gold at Bucium-Izbiţa. For Pietroasa hoard, we found Sn in the Oenochoe cup and small fibula, indicating that alluvial gold - probably from Anatolia (Pactolus river) - was used. We also detected Ta inclusions in the large fibula, indicating that Ural Mountains (the only region where Ta and Au minerals are together) gold was (at least partially) used. A spectacular application to nine Dacian gold bracelets (belonging to National History Museum of Romania) authentication is presented. These bracelets look like spirals and are based on the same artistic idea, are centred around the same theme. The number of spiral varies from 6 to 8. When uncoiled, some bracelets

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.

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.

Aroma Release in Wine Using Co-Immobilized Enzyme Aggregates.

PubMed

Ahumada, Katherine; Martínez-Gil, Ana; Moreno-Simunovic, Yerko; Illanes, Andrés; Wilson, Lorena

2016-11-08

Aroma is a remarkable factor of quality and consumer preference in wine, representing a distinctive feature of the product. Most aromatic compounds in varietals are in the form of glycosidic precursors, which are constituted by a volatile aglycone moiety linked to a glucose residue by an O -glycosidic bond; glucose is often linked to another sugar (arabinose, rhamnose or apiose). The use of soluble β-glycosidases for aroma liberation implies the addition of a precipitating agent to remove it from the product and precludes its reuse after one batch. An attractive option from a technological perspective that will aid in removing such constraints is the use of immobilized glycosidases. Immobilization by aggregation and crosslinking is a simple strategy producing enzyme catalysts of very high specific activity, being an attractive option to conventional immobilization to solid inert supports. The purpose of this work was the evaluation of co-immobilized β-glycosidases crosslinked aggregates produced from the commercial preparation AR2000, which contains the enzymes involved in the release of aromatic terpenes in Muscat wine (α-l-arabinofuranosidase and β-d-glucopyranosidase). To do so, experiments were conducted with co-immobilized crosslinked enzyme aggregates (combi-CLEAs), and with the soluble enzymes, using an experiment without enzyme addition as control. Stability of the enzymes at the conditions of winemaking was assessed and the volatiles composition of wine was determined by SPE-GC-MS. Stability of enzymes in combi-CLEAs was much higher than in soluble form, 80% of the initial activity remaining after 60 days in contact with the wine; at the same conditions, the soluble enzymes had lost 80% of their initial activities after 20 days. Such higher stabilities will allow prolonged use of the enzyme catalyst reducing its impact in the cost of winemaking. Wine treated with combi-CLEAs was the one exhibiting the highest concentration of total terpenes (18% higher

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";…

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.

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.

Potential immobilized Saccharomyces cerevisiae as heavy metal removal

NASA Astrophysics Data System (ADS)

Raffar, Nur Izzati Abdul; Rahman, Nadhratul Nur Ain Abdul; Alrozi, Rasyidah; Senusi, Faraziehan; Chang, Siu Hua

2015-05-01

Biosorption of copper ion using treated and untreated immobilized Saccharomyces cerevisiae from aqueous solution was investigate in this study. S.cerevisiae has been choosing as biosorbent due to low cost, easy and continuously available from various industries. In this study, the ability of treated and untreated immobilized S.cerevisiae in removing copper ion influence by the effect of pH solution, and initial concentration of copper ion with contact time. Besides, adsorption isotherm and kinetic model also studied. The result indicated that the copper ion uptake on treated and untreated immobilized S.cerevisiae was increased with increasing of contact time and initial concentration of copper ion. The optimum pH for copper ion uptake on untreated and treated immobilized S.cerevisiae at 4 and 6. From the data obtained of copper ion uptake, the adsorption isotherm was fitted well by Freundlich model for treated immobilized S.cerevisiae and Langmuir model for untreated immobilized S.cerevisiae according to high correlation coefficient. Meanwhile, the pseudo second order was described as suitable model present according to high correlation coefficient. Since the application of biosorption process has been received more attention from numerous researchers as a potential process to be applied in the industry, future study will be conducted to investigate the potential of immobilized S.cerevisiae in continuous process.

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.

Limb immobilization and corticobasal syndrome.

PubMed

Graff-Radford, Jonathan; Boeve, Bradley F; Drubach, Daniel A; Knopman, David S; Ahlskog, J Eric; Golden, Erin C; Drubach, Dina I; Petersen, Ronald C; Josephs, Keith A

2012-12-01

Recently, we evaluated two patients with corticobasal syndrome (CBS) who reported symptom onset after limb immobilization. Our objective was to investigate the association between trauma, immobilization and CBS. The charts of forty-four consecutive CBS patients seen in the Mayo Clinic Alzheimer Disease Research Center were reviewed with attention to trauma and limb immobilization. 10 CBS patients (23%) had immobilization or trauma on the most affected limb preceding the onset or acceleration of symptoms. The median age at onset was 61. Six patients manifested their first symptoms after immobilization from surgery or fracture with one after leg trauma. Four patients had pre-existing symptoms of limb dysfunction but significantly worsened after immobilization or surgery. 23 percent of patients had immobilization or trauma of the affected limb. This might have implications for management of CBS, for avoiding injury, limiting immobilization and increasing movement in the affected limb. Copyright © 2012 Elsevier Ltd. All rights reserved.

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.

THE MULTIELEMENTAL ANALYSIS OF DRINKING WATER USING PROTON-INDUCED X-RAY EMISSION (PIXE)

EPA Science Inventory

A new, rapid, and economical method for the multielemental analysis of drinking water samples is described. The concentrations of 76 elements heavier than aluminum are determined using proton-induced x-ray emission (PIXE) technology. The concentration of sodium is evaluated using...

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.

Long term fine aerosol analysis by XRF and PIXE techniques in the city of Rijeka, Croatia

NASA Astrophysics Data System (ADS)

Ivošević, Tatjana; Orlić, Ivica; Radović, Iva Bogdanović

2015-11-01

The results of a long term, multi elemental XRF and PIXE analysis of fine aerosol pollution in the city of Rijeka, Croatia, are reported for the first time. The samples were collected during a seven months period (6th Aug 2013-28th Feb 2014) on thin stretched Teflon filters and analyzed by energy dispersive X-ray fluorescence (EDXRF) at the Laboratory for Elemental Micro-Analysis (LEMA), University of Rijeka and by Particle Induced X-ray Emission (PIXE) using 1.6 MeV protons at the Laboratory for Ion Beam Interactions (LIBI), Ruđer Bošković Institute, Zagreb. The newly developed micro-XRF system at LEMA provided results for 19 elements in the range from Si to Pb. The PIXE at the LIBI provided information for the same elements as well for the light elements such as Na, Mg and Al. Black carbon was determined with the Laser Integrated Plate Method (LIPM). The results were statistically evaluated by means of the positive matrix factorization (PMF). The seven major pollution sources were identified together with their relative contributions, these are: secondary sulfates, road traffic, smoke, road dust, sea spray, ship emissions and soil dust.

Modification of Immobead 150 support for protein immobilization: effects on the properties of immobilized Aspergillus oryzae β-galactosidase.

PubMed

Gennari, Adriano; Herrmann Mobayed, Francielle; da Silva Rafael, Ruan; Rodrigues, Rafael C; Sperotto, Raul Antonio; Volpato, Giandra; Volken de Souza, Claucia Fernanda

2018-05-01

We studied the modification of Immobead 150 support by either introducing aldehyde groups using glutaraldehyde (Immobead-Glu) or carboxyl groups through acid solution (Immobead-Ac) for enzyme immobilization by covalent attachment or ion exchange, respectively. These two types of immobilization were compared with the use of epoxy groups that are now provided on a commercial support. We used Aspergillus oryzae β-galactosidase (Gal) as a model protein, immobilizing it on unmodified (epoxy groups, Immobead-Epx) and modified supports. Immobilization yield and efficiency were tested as a function of protein loading (10 to 500 mg.g -1 support). Gal was efficiently immobilized on the Immobeads with an immobilization efficiency higher than 75% for almost all supports and protein loads. Immobilization yields significantly decreased when protein loadings were higher than 100 mg.g -1 support. Gal immobilized on Immobead-Glu and Immobead-Ac retained approximately 60% of its initial activity after 90 days of storage at 4°C. The three immobilized Gal derivatives presented higher half-lifes than the soluble enzyme, where the half-lifes were twice higher than the free Gal at 73°C. All the preparations were moderately operationally stable when tested in lactose solution, whey permeate, cheese whey, and skim milk, and retained approximately 50% of their initial activity after 20 cycles of hydrolyzing lactose solution. The modification of the support with glutaraldehyde provided the most stable derivative during cycling in cheese whey hydrolysis. Our results suggest that the Immobead 150 is a promising support for Gal immobilization. This article is protected by copyright. All rights reserved. © 2018 American Institute of Chemical Engineers.

Immobilization patterns and dynamics of acetate-utilizing methanogens immobilized in sterile granular sludge in upflow anaerobic sludge blanket reactors.

PubMed

Schmidt, J E; Ahring, B K

1999-03-01

Sterile granular sludge was inoculated with either Methanosarcina mazeii S-6, Methanosaeta concilii GP-6, or both species in acetate-fed upflow anaerobic sludge blanket (UASB) reactors to investigate the immobilization patterns and dynamics of aceticlastic methanogens in granular sludge. After several months of reactor operation, the methanogens were immobilized, either separately or together. The fastest immobilization was observed in the reactor containing M. mazeii S-6. The highest effluent concentration of acetate was observed in the reactor with only M. mazeii S-6 immobilized, while the lowest effluent concentration of acetate was observed in the reactor where both types of methanogens were immobilized together. No changes were observed in the kinetic parameters (Ks and mumax) of immobilized M. concilii GP-6 or M. mazeii S-6 compared with suspended cultures, indicating that immobilization does not affect the growth kinetics of these methanogens. An enzyme-linked immunosorbent assay using polyclonal antibodies against either M. concilii GP-6 or M. mazeii S-6 showed significant variations in the two methanogenic populations in the different reactors. Polyclonal antibodies were further used to study the spatial distribution of the two methanogens. M. concilii GP-6 was immobilized only on existing support material without any specific pattern. M. mazeii S-6, however, showed a different immobilization pattern: large clumps were formed when the concentration of acetate was high, but where the acetate concentration was low this strain was immobilized on support material as single cells or small clumps. The data clearly show that the two aceticlastic methanogens immobilize differently in UASB systems, depending on the conditions found throughout the UASB reactor.

Immobilization Patterns and Dynamics of Acetate-Utilizing Methanogens Immobilized in Sterile Granular Sludge in Upflow Anaerobic Sludge Blanket Reactors

PubMed Central

Schmidt, Jens Ejbye; Ahring, Birgitte Kjær

1999-01-01

Sterile granular sludge was inoculated with either Methanosarcina mazeii S-6, Methanosaeta concilii GP-6, or both species in acetate-fed upflow anaerobic sludge blanket (UASB) reactors to investigate the immobilization patterns and dynamics of aceticlastic methanogens in granular sludge. After several months of reactor operation, the methanogens were immobilized, either separately or together. The fastest immobilization was observed in the reactor containing M. mazeii S-6. The highest effluent concentration of acetate was observed in the reactor with only M. mazeii S-6 immobilized, while the lowest effluent concentration of acetate was observed in the reactor where both types of methanogens were immobilized together. No changes were observed in the kinetic parameters (Ks and μmax) of immobilized M. concilii GP-6 or M. mazeii S-6 compared with suspended cultures, indicating that immobilization does not affect the growth kinetics of these methanogens. An enzyme-linked immunosorbent assay using polyclonal antibodies against either M. concilii GP-6 or M. mazeii S-6 showed significant variations in the two methanogenic populations in the different reactors. Polyclonal antibodies were further used to study the spatial distribution of the two methanogens. M. concilii GP-6 was immobilized only on existing support material without any specific pattern. M. mazeii S-6, however, showed a different immobilization pattern: large clumps were formed when the concentration of acetate was high, but where the acetate concentration was low this strain was immobilized on support material as single cells or small clumps. The data clearly show that the two aceticlastic methanogens immobilize differently in UASB systems, depending on the conditions found throughout the UASB reactor. PMID:10049862

Laccase production by free and immobilized mycelia of Peniophora cinerea and Trametes versicolor: a comparative study.

PubMed

Silvério, Sara C; Moreira, Sérgio; Milagres, Adriane M F; Macedo, Eugénia A; Teixeira, José A; Mussatto, Solange I

2013-03-01

The production of laccase by immobilized mycelia of Peniophora cinerea and Trametes versicolor was studied. In an initial stage, experimental assays were performed in Erlenmeyer flasks using free and immobilized mycelium, and the performance of the fungal strains to produce the enzyme was compared. Both fungi adhered into the support material (a synthetic fiber), growing not only on the surface but also in the interspaces of the fibers. Immobilization of P. cinerea provided a 35-fold increase in laccase production when compared to the production obtained by using free mycelium. On the other hand, immobilization of T. versicolor caused a decrease in laccase activity. A comparison between the strains revealed that immobilized P. cinerea (3,500 U/L) surpassed the enzyme production by free T. versicolor (800 U/L). When the conditions that gave the best laccase production to each fungus were employed in a stirred tank bioreactor, very low laccase production was observed for both the cases, suggesting that shear stress and mycelia damage caused by the agitation impellers negatively affected the enzyme production.

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.

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

Gamma radiation grafted polymers for immobilization of Brucella antigen in diagnostic test studies

NASA Astrophysics Data System (ADS)

Docters, E. H.; Smolko, E. E.; Suarez, C. E.

The radiation grafting process has a wide field of industrial applications, and in the recent years the immobilization of biocomponents in grafted polymeric materials obtained by means of ionizing radiations is a new and important contribution to biotechnology. In the present work, gamma preirradiation grafting method was employed to produce acrylics hydrogels onto polyethylene (PE), polyvinyl chloride (PVC) and polystyrene (PS). Two monomers were used to graft the previously mentioned polymers: methacrylic acid (MAAc) and acrylamide (AAm), and several working conditions were considered as influencing the degree of grafting. All this grafted polymers were used to study the possibility of a subsequent immobilization of Brucella antigen (BAg) in diagnostic test studies (ELISA).

Design and characterization of a prototype enzyme microreactor: quantification of immobilized transketolase kinetics.

PubMed

Matosevic, S; Lye, G J; Baganz, F

2010-01-01

In this work, we describe the design of an immobilized enzyme microreactor (IEMR) for use in transketolase (TK) bioconversion process characterization. The prototype microreactor is based on a 200-microm ID fused silica capillary for quantitative kinetic analysis. The concept is based on the reversible immobilization of His(6)-tagged enzymes via Ni-NTA linkage to surface derivatized silica. For the initial microreactor design, the mode of operation is a stop-flow analysis which promotes higher degrees of conversion. Kinetics for the immobilized TK-catalysed synthesis of L-erythrulose from substrates glycolaldehyde (GA) and hydroxypyruvate (HPA) were evaluated based on a Michaelis-Menten model. Results show that the TK kinetic parameters in the IEMR (V(max(app)) = 0.1 +/- 0.02 mmol min(-1), K(m(app)) = 26 +/- 4 mM) are comparable with those measured in free solution. Furthermore, the k(cat) for the microreactor of 4.1 x 10(5) s(-1) was close to the value for the bioconversion in free solution. This is attributed to the controlled orientation and monolayer surface coverage of the His(6)-immobilized TK. Furthermore, we show quantitative elution of the immobilized TK and the regeneration and reuse of the derivatized capillary over five cycles. The ability to quantify kinetic parameters of engineered enzymes at this scale has benefits for the rapid and parallel evaluation of evolved enzyme libraries for synthetic biology applications and for the generation of kinetic models to aid bioconversion process design and bioreactor selection as a more efficient alternative to previously established microwell-based systems for TK bioprocess characterization.

Status of plutonium ceramic immobilization processes and immobilization forms

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

Ebbinghaus, B.B.; Van Konynenburg, R.A.; Vance, E.R.

1996-05-01

Immobilization in a ceramic followed by permanent emplacement in a repository or borehole is one of the alternatives currently being considered by the Fissile Materials Disposition Program for the ultimate disposal of excess weapons-grade plutonium. To make Pu recovery more difficult, radioactive cesium may also be incorporated into the immobilization form. Valuable data are already available for ceramics form R&D efforts to immobilize high-level and mixed wastes. Ceramics have a high capacity for actinides, cesium, and some neutron absorbers. A unique characteristic of ceramics is the existence of mineral analogues found in nature that have demonstrated actinide immobilization over geologicmore » time periods. The ceramic form currently being considered for plutonium disposition is a synthetic rock (SYNROC) material composed primarily of zirconolite (CaZrTi{sub 2}O{sub 7}), the desired actinide host phase, with lesser amounts of hollandite (BaAl{sub 2}Ti{sub 6}O{sub 16}) and rutile (TiO{sub 2}). Alternative actinide host phases are also being considered. These include pyrochlore (Gd{sub 2}Ti{sub 2}O{sub 7}), zircon (ZrSiO{sub 4}), and monazite (CePO{sub 4}), to name a few of the most promising. R&D activities to address important technical issues are discussed. Primarily these include moderate scale hot press fabrications with plutonium, direct loading of PuO{sub 2} powder, cold press and sinter fabrication methods, and immobilization form formulation issues.« less

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…

Comparison between Free and Immobilized Ion Effects on Hydrophobic Interactions: A Molecular Dynamics Study.

PubMed

Huang, Kai; Gast, Sebastian; Ma, C Derek; Abbott, Nicholas L; Szlufarska, Izabela

2015-10-15

Fundamental studies of the effect of specific ions on hydrophobic interactions are driven by the need to understand phenomena such as hydrophobically driven self-assembly or protein folding. Using β-peptide-inspired nanorods, we investigate the effects of both free ions (dissolved salts) and proximally immobilized ions on hydrophobic interactions. We find that the free ion effect is correlated with the water density fluctuation near a nonpolar molecular surface, showing that such fluctuation can be an indicator of hydrophobic interactions in the case of solution additives. In the case of immobilized ion, our results demonstrate that hydrophobic interactions can be switched on and off by choosing different spatial arrangements of proximal ions on a nanorod. For globally amphiphilic nanorods, we find that the magnitude of the interaction can be further tuned using proximal ions with varying ionic sizes. In general, univalent proximal anions are found to weaken hydrophobic interactions. This is in contrast to the effect of free ions, which according to our simulations strengthen hydrophobic interactions. In addition, immobilized anions of increasing ionic size do not follow the same ordering (Hofmeister-like ranking) as free ions when it comes to their impact on hydrophobic interactions. The immobilized ion effect is not simply correlated with the water density fluctuation near the nonpolar side of the amphiphilic nanorod. We propose a molecular picture that explains the contrasting effects of immobilized versus free ions.

Advances in ethanol production using immobilized cell systems

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

Margaritis, A.; Merchant, F.J.A.

The application of immobilized cell systems for the production of ethanol has resulted in substantial improvements in the efficiency of the process when compared to the traditional free cell system. In this review, the various methods of cell immobilization employed in ethanol production systems have been described in detail. Their salient features, performance characteristics, advantages and limitations have been critically assessed. More recently, these immobilized cell systems have also been employed for the production of ethanol from non-conventional feedstocks such as Jerusalem artichoke extracts, cheese whey, cellulose, cellobiose and xylose. Ethanol production by immobilized yeast and bacterial cells has beenmore » attempted in various bioreactor types. Although most of these studies have been carried out using laboratory scale prototype bioreactors, it appears that only fluidized bed, horizontally packed bed bioreactors and tower fermenters may find application on scale-up. Several studies have indicated that upon immobilization, yeast cells performing ethanol fermentation exhibit more favourable physiological and metabolic properties. This, in addition to substantial improvements in ethanol productivities by immobilized cell systems, is indicative of the fact that future developments in the production of ethanol and alcoholic beverages will be directed towards the use of immobilized cell systems. 291 references.« less

[Immobilization of introduced bacteria and degradation of pyrene and benzo(alpha) pyrene in soil by immobilized bacteria].

PubMed

Wang, Xin; Li, Peijun; Song, Shouzhi; Zhong, Yong; Zhang, Hui; Verkhozina, E V

2006-11-01

In this study, introduced bacteria were applied in the bioremediation of pyrene and benzo (alpha) pyrene in organic pollutants-contaminated soils, aimed to test whether it was feasible to introduce bacteria to environmental engineering. Three introduced bacteria were immobilized separately or together to degrade the pyrene and benzo (alpha) pyrene in soil, taking dissociated bacteria as the control, and comparing with three indigenous bacteria. The results showed that immobilized introduced bacteria, either single or mixed, had higher degradation efficiency than dissociated bacteria. Compared with indigenous bacteria, some introduced bacteria had predominance to some degree. The introduced bacteria-mixture had better degradation efficiency after being immobilized. The degradation rate of pyrene and benzo(alpha) pyrene after treated with immobilized bacteria-( B61-B67)-mixture for 96 hours was 43.49% and 38.55%, respectively.

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.

Micro-PIXE study of metal loss from dental amalgam

NASA Astrophysics Data System (ADS)

Meesat, Ridthee; Sudprasert, Wanwisa; Guibert, Edouard; Wang, Liping; Chappuis, Thibault; Whitlow, Harry J.

2017-08-01

Mercury amalgams have been a topic of controversy ever since their introduction over 150 years ago as a dental material. An interesting question is if metals are released from the amalgam into the enamel and dentine tissue. To elucidate this PIXE mapping was used to investigate metal redistribution in an extracted molar tooth with a ∼30 year old high-Cu content amalgam filling. The tooth was sectioned and polished, and elemental mapping carried out on the amalgam/enamel, bulk amalgam and the wear surface of the amalgam. As expected, the amalgam was multiphase amalgam comprising of Cu-rich and Ag-rich grains with non-uniform distribution of Hg. The amalgam/dentine interface was clearly defined with amalgam elements on one side and C and P from hydroxyapatite on the other side with evidence of only slight interface corrosion. The peaks for Cu Hg and Zn were isolated from interfering signals with concentrations in the enamel tissue, observed to be at, or below the method detection limit. The proximity in energy of the Sn L α and Ca K α , peaks and the background on the Hg M α gave signal overlap which increased the MDL for these elements. Remarkably, a course grain texture in the amalgam was observed just below the biting surface of the amalgam which might be associated with tribochemical processes from mastication. This coupled with the clear absence of the amalgam metals from tooth tissue, even in close proximity to the interface, suggests that for this sample, release of Hg occurred via erosion or dissolution in saliva.

A preliminary study of continuous milk coagulation using Cynara cardunculus flower extract and calf rennet immobilized on magnetic particles.

PubMed

Liburdi, Katia; Emiliani Spinelli, Sara; Benucci, Ilaria; Lombardelli, Claudio; Esti, Marco

2018-01-15

The aim of this study was to develop a bioreactor design for continuous milk coagulation using a biocatalyst composed of immobilized animal and vegetable rennet on aminated magnetic particles, which has been proven to be an appropriate carrier for enzyme immobilization. Calf and vegetable (Cynara cardunculus) rennets were covalently immobilized on CLEA® magnetic supports and the immobilization procedure was optimized in batch mode, by evaluating protein loading, caseinolytic activity and the coagulation properties of skim milk powder and cow's milk. Subsequently the optimal temperature of immobilized coagulant was defined and a technically-friendly enzyme bioreactor was developed in order to carry out a continuous milk coagulation process with the aim of producing soft cheese. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Influence of Ambulatory Aid on Lower-Extremity Muscle Activation During Gait.

PubMed

Sanders, Michael; Bowden, Anton E; Baker, Spencer; Jensen, Ryan; Nichols, McKenzie; Seeley, Matthew K

2018-05-10

Foot and ankle injuries are common and often require a nonweight-bearing period of immobilization for the involved leg. This nonweight-bearing period usually results in muscle atrophy for the involved leg. There is a dearth of objective data describing muscle activation for different ambulatory aids that are used during the aforementioned nonweight-bearing period. To compare activation amplitudes for 4 leg muscles during (1) able-bodied gait and (2) ambulation involving 3 different ambulatory aids that can be used during the acute phase of foot and ankle injury care. Within-subject, repeated measures. University biomechanics laboratory. Sixteen able-bodied individuals (7 females and 9 males). Each participant performed able-bodied gait and ambulation using 3 different ambulatory aids (traditional axillary crutches, knee scooter, and a novel lower-leg prosthesis). Muscle activation amplitude quantified via mean surface electromyography amplitude throughout the stance phase of ambulation. Numerous statistical differences (P < .05) existed for muscle activation amplitude between the 4 observed muscles, 3 ambulatory aids, and able-bodied gait. For the involved leg, comparing the 3 ambulatory aids: (1) knee scooter ambulation resulted in the greatest vastus lateralis activation, (2) ambulation using the novel prosthesis and traditional crutches resulted in greater biceps femoris activation than knee scooter ambulation, and (3) ambulation using the novel prosthesis resulted in the greatest gastrocnemius activation (P < .05). Generally speaking, muscle activation amplitudes were most similar to able-bodied gait when subjects were ambulating using the knee scooter or novel prosthesis. Type of ambulatory aid influences muscle activation amplitude. Traditional axillary crutches appear to be less likely to mitigate muscle atrophy during the nonweighting, immobilization period that often follows foot or ankle injuries. Researchers and clinicians should consider

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.

Carbodiimide for Covalent α-Amylase Immobilization onto Magnetic Nanoparticles

NASA Astrophysics Data System (ADS)

Milani, Zeinab Mortazavi; Jalal, Razieh; Goharshadi, Elaheh K.

Covalent cross-linking of enzymes to magnetite (Fe3O4) nanoparticles (MNPs) is one of the useful enzyme immobilization methods which provides repeated use of the catalyst, facilitates enzyme separation from the reaction mixture, and sometimes improves biocatalysts stability. The aim of this study was to immobilize α-amylase onto MNPs via covalent attachment using carbodiimide (CDI) molecules. MNPs were synthesized by the co-precipitation method. The size and the structure of the particles were characterized by X-ray diffraction and transmission electron microscopy. The effects of different operational conditions of direct α-amylase binding on MNPs in the presence of CDI were investigated by using the shaking method. Fourier transform infrared spectroscopy was used to confirm the success of immobilization. The optimum conditions and catalytic properties of immobilized α-amylase were also evaluated. The efficiency of immobilization and the residual activity of the immobilized α-amylase were dependent on the mass ratio of MNPs: CDI: α-amylase and the immobilization temperature. The optimum pH for the free and immobilized amylase was 6. The free and immobilized α-amylase showed maximum activity at 20∘C and 35∘C, respectively. The immobilized α-amylase was more thermostable than the free one. The retained activity for free α-amylase after 19 storage days was 57.7% whereas it was 100% for the immobilized α-amylase. In repeated batch experiments, the immobilized α-amylase retained a residual activity of 45% after 11 repeated uses. The Km and Vmax values for the immobilized enzyme were larger than those of the free enzyme. The immobilization of α-amylase on MNPs using CDI improves its stability and reusability.

Metabolic alkalosis during immobilization in monkeys (M. nemestrina)

NASA Technical Reports Server (NTRS)

Young, D. R.; Yeh, I.; Swenson, R. S.

1983-01-01

The systemic and renal acid-base response of monkeys during ten weeks of immobilization was studied. By three weeks of immobilization, arterial pH and bicarbonate concentrations were elevated (chronic metabolic alkalosis). Net urinary acid excretion increased in immobilized animals. Urinary bicarbonate excretion decreased during the first three weeks of immobilization, and then returned to control levels. Sustained increases in urinary ammonium excretion were seen throughout the time duration of immobilization. Neither potassium depletion nor hypokalemia was observed. Most parameters returned promptly to the normal range during the first week of recovery. Factors tentatively associated with changes in acid-base status of monkeys include contraction of extracellular fluid volume, retention of bicarbonate, increased acid excretion, and possible participation of extrarenal buffers.

Polymeric brushes as functional templates for immobilizing ribonuclease A: study of binding kinetics and activity.

PubMed

Cullen, Sean P; Liu, Xiaosong; Mandel, Ian C; Himpsel, Franz J; Gopalan, Padma

2008-02-05

The ability to immobilize proteins with high binding capacities on surfaces while maintaining their activity is critical for protein microarrays and other biotechnological applications. We employed poly(acrylic acid) (PAA) brushes as templates to immobilize ribonuclease A (RNase A), which is commonly used to remove RNA from plasmid DNA preparations. The brushes are grown by surface-anchored atom-transfer radical polymerization (ATRP) initiators. RNase A was immobilized by both covalent esterification and a high binding capacity metal-ion complexation method to PAA brushes. The polymer brushes immobilized 30 times more enzyme compared to self-assembled monolayers. As the thickness of the brush increases, the surface density of the RNase A increases monotonically. The immobilization was investigated by ellipsometry, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and near-edge X-ray absorption fine structure spectroscopy (NEXAFS). The activity of the immobilized RNase A was determined using UV absorbance. As much as 11.0 microg/cm(2) of RNase A was bound to PAA brushes by metal-ion complexation compared to 5.8 microg/cm(2) by covalent immobilization which is 30 and 16 times the estimated mass bound in a monolayer. The calculated diffusion coefficient D was 0.63 x 10(-14) cm(2)/s for metal-ion complexation and 0.71 x 10(-14) cm(2)/s for covalent immobilization. Similar values of D indicate that the binding kinetics is similar, but the thermodynamic equilibrium coverage varies with the binding chemistry. Immobilization kinetics and thermodynamics were characterized by ellipsometry for both methods. A maximum relative activity of 0.70-0.80 was reached between five and nine monolayers of the immobilized enzyme. However, the relative activity for covalent immobilization was greater than that of metal-ion complexation. Covalent esterification resulted in similar temperature dependence as free enzyme, whereas metal-ion complexation showed no

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.

Immobilization of Aspergillus niger xylanase on magnetic latex beads.

PubMed

Tyagi, R; Gupta, M N

1995-04-01

Xylanase from Pectinex 3XL was purified 70-fold by precipitation with an enteric polymer, Eudragit S-100. The purified xylanase was immobilized on magnetic latex beads via carbodi-imide coupling. The immobilized preparation showed 80% of the total activity bound to the beads. The pH optimum remained unchanged at 6.0 and the Km increased from 0.25 g/100 ml (free enzyme) to 0.39 g/100 ml on immobilization. Immobilization resulted in significant thermal stability at 60 degrees C. The time course of hydrolysis of xylan at 60 degrees C by free enzyme as well as immobilized enzyme was also studied.

Hydrolysis of triacetin catalyzed by immobilized lipases: effect of the immobilization protocol and experimental conditions on diacetin yield.

PubMed

Hernandez, Karel; Garcia-Verdugo, Eduardo; Porcar, Raul; Fernandez-Lafuente, Roberto

2011-05-06

The effect of the immobilization protocol and some experimental conditions (pH value and presence of acetonitrile) on the regioselective hydrolysis of triacetin to diacetin catalyzed by lipases has been studied. Lipase B from Candida antarctica (CALB) and lipase from Rhizomucor miehei (RML) were immobilized on Sepabeads (commercial available macroporous acrylic supports) activated with glutaraldehyde (covalent immobilization) or octadecyl groups (adsorption via interfacial activation). All the biocatalysts accumulated diacetin. Covalently immobilized RML was more active towards rac-methyl mandelate than the adsorbed RML. However, this covalent RML preparation presented the lowest activity towards triacetin. For this reason, this preparation was discarded as biocatalyst for this reaction. At pH 7, acyl migration occurred giving a mixture of 1,2 and 1,3 diacetin, but at pH 5.5, only 1,2 diacetin was produced. Yields were improved at acidic pH values and in the presence of 20% acetonitrile (to over 95%). RML immobilized on octadecyl Sepabeads was proposed as optimal preparation, mainly due to its higher specific activity. Each enzyme preparation presented very different properties. Moreover, changes in the reaction conditions affected the various immobilized enzymes in a different way. Copyright © 2011 Elsevier Inc. All rights reserved.

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.

Short-Term Upper Limb Immobilization Affects Action-Word Understanding

ERIC Educational Resources Information Center

Bidet-Ildei, Christel; Meugnot, Aurore; Beauprez, Sophie-Anne; Gimenes, Manuel; Toussaint, Lucette

2017-01-01

The present study aimed to investigate whether well-established associations between action and language can be altered by short-term upper limb immobilization. The dominant arm of right-handed participants was immobilized for 24 hours with a rigid splint fixed on the hand and an immobilization vest restraining the shoulder, arm, and forearm. The…

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.

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.

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.

Biosensor studies of collagen and laminin binding with immobilized Escherichia coli O157:H7 and inhibition with naturally occurring food additives

NASA Astrophysics Data System (ADS)

Medina, Marjorie B.

1999-01-01

Escherichia coli O157:H7 outbreaks were mostly due to consumption of undercooked contaminated beef which resulted in severe illness and several fatalities. Recalls of contaminated meat are costly for the meat industry. Our research attempts to understand the mechanisms of bacterial adhesion on animal carcass in order to eliminate or reduce pathogens in foods. We have reported the interactions of immobilized E. coli O157:H7 cells with extracellular matrix (ECM) components using a surface plasmon resonance biosensor (BIAcore). These studies showed that immobilized bacterial cells allowed the study of real-time binding interactions of bacterial surface with the ECM compounds, collagen I, laminin and fibronectin. Collagen I and laminin bound to the E. coli sensor surface with dissociation and association rates ranging from 106 to 109. Binding of collagen I and laminin mixture resulted in synergistic binding signals. An inhibition model was derived using collagen-laminin as the ligand which binds with E. coli sensor. A select group of naturally occurring food additives was evaluated by determining their effectivity in inhibiting the collagen-laminin binding to the bacterial sensor. Bound collagen-laminin was detached from the E. coli sensor surface with the aid of an organic acid. The biosensor results were verified with cell aggregation assays which were observed with optical and electron microscopes. These biosensor studies provided understanding of bacterial adhesion to connective tissue macromolecules. It also provided a model system for the rapid assessment of potential inhibitors that can be used in carcass treatment to inhibit or reduce bacterial contamination.

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.

Is prolonged immobilization a risk factor for symptomatic venous thromboembolism in elderly bedridden patients? Results of a historical-cohort study.

PubMed

Gatt, Moshe E; Paltiel, Ora; Bursztyn, Michael

2004-03-01

Prolonged immobilization and advanced age are considered to be important risk factors for venous thromboembolism (VTE). Nevertheless, the need for VTE prophylaxis in long-term bedridden patients is not known. To assess whether very prolonged immobilization (i.e. over three months) carries an increased risk for clinically apparent VTE, we performed a historical-cohort study of nursing home residents during a ten-year period. Data concerning patient's mobility and incidence of overt deep vein thrombosis or pulmonary embolism were registered. The mean resident age was 85+/-8.4 years. Eighteen mobile and eight immobile patients were diagnosed with clinically significant thromboembolic events, during 1137 and 573 patient-years of follow up, respectively. The incidence of venous thromboembolic events was similar in both chronically immobilized and mobile patient groups, 13.9 and 15.8 per thousand patient years, respectively (p=0.77). The rate ratio for having a VTE event in the immobilized patient group as compared with the mobile group was 0.88 (95% Confidence Interval (CI) 0.33 to 2.13). When taking into account baseline characteristics, risk factors and death rates by various causes, no differences were found between the two groups. In conclusion, chronically immobile bedridden patients are no more prone to clinically overt venous thromboembolic events than institutionalized mobile patients. Until further studies are performed concerning the impact of very prolonged immobilization on the risk of VTE, there is no evidence to support primary prevention after the first three months of immobilization. Evidence for efficacy or cost effectiveness beyond this early period is not available.

Immobilized lysozyme for the continuous lysis of lactic bacteria in wine: Bench-scale fluidized-bed reactor study.

PubMed

Cappannella, Elena; Benucci, Ilaria; Lombardelli, Claudio; Liburdi, Katia; Bavaro, Teodora; Esti, Marco

2016-11-01

Lysozyme from hen egg white (HEWL) was covalently immobilized on spherical supports based on microbial chitosan in order to develop a system for the continuous, efficient and food-grade enzymatic lysis of lactic bacteria (Oenococcus oeni) in white and red wine. The objective is to limit the sulfur dioxide dosage required to control malolactic fermentation, via a cell concentration typical during this process. The immobilization procedure was optimized in batch mode, evaluating the enzyme loading, the specific activity, and the kinetic parameters in model wine. Subsequently, a bench-scale fluidized-bed reactor was developed, applying the optimized process conditions. HEWL appeared more effective in the immobilized form than in the free one, when the reactor was applied in real white and red wine. This preliminary study suggests that covalent immobilization renders the enzyme less sensitive to the inhibitory effect of wine flavans. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

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

Titanium Immobilized with an Antimicrobial Peptide Derived from Histatin Accelerates the Differentiation of Osteoblastic Cell Line, MC3T3-E1

PubMed Central

Makihira, Seicho; Shuto, Takahiro; Nikawa, Hiroki; Okamoto, Keishi; Mine, Yuichi; Takamoto, Yuko; Ohara, Masaru; Tsuji, Koichiro

2010-01-01

The objective of this study was to evaluate the effect of titanium immobilized with a cationic antimicrobial peptide (JH8194) derived from histatin on the biofilm formation of Porphyromonas gingivalis and differentiation of osteoblastic cells (MC3T3-E1). The titanium specimens (Ti) were immobilized with JH8194, according to the method previously described. The colonization of P. gingivalis on JH8194-Ti was significantly lower than that on control- and blocking-Ti. JH8194-Ti enhanced the mRNA expressions of Runx2 and OPN, and ALPase activity in the MC3T3-E1, as compared with those of control- and blocking-Ti. These results, taken together, suggested the possibility that JH8194-Ti may be a potential aid to shorten the period of acquiring osseointegration. PMID:20480030

Direct Electrochemical Addressing of Immobilized Alcohol Dehydrogenase for the Heterogeneous Bioelectrocatalytic Reduction of Butyraldehyde to Butanol.

PubMed

Schlager, S; Neugebauer, H; Haberbauer, M; Hinterberger, G; Sariciftci, N S

2015-03-01

Modified electrodes using immobilized alcohol dehydrogenase enzymes for the efficient electroreduction of butyraldehyde to butanol are presented as an important step for the utilization of CO 2 -reduction products. Alcohol dehydrogenase was immobilized, embedded in an alginate-silicate hybrid gel, on a carbon felt (CF) electrode. The application of this enzyme to the reduction of an aldehyde to an alcohol with the aid of the coenzyme nicotinamide adenine dinucleotide (NADH), in analogy to the final step in the natural reduction cascade of CO 2 to alcohol, has been already reported. However, the use of such enzymatic reductions is limited because of the necessity of providing expensive NADH as a sacrificial electron and proton donor. Immobilization of such dehydrogenase enzymes on electrodes and direct pumping of electrons into the biocatalysts offers an easy and efficient way for the biochemical recycling of CO 2 to valuable chemicals or alternative synthetic fuels. We report the direct electrochemical addressing of immobilized alcohol dehydrogenase for the reduction of butyraldehyde to butanol without consumption of NADH. The selective reduction of butyraldehyde to butanol occurs at room temperature, ambient pressure and neutral pH. Production of butanol was detected by using liquid-injection gas chromatography and was estimated to occur with Faradaic efficiencies of around 40 %.

Microorganism immobilization

DOEpatents

Compere, Alicia L.; Griffith, William L.

1981-01-01

Live metabolically active microorganisms are immobilized on a solid support by contacting particles of aggregate material with a water dispersible polyelectrolyte such as gelatin, crosslinking the polyelectrolyte by reacting it with a crosslinking agent such as glutaraldehyde to provide a crosslinked coating on the particles of aggregate material, contacting the coated particles with live microorganisms and incubating the microorganisms in contact with the crosslinked coating to provide a coating of metabolically active microorganisms. The immobilized microorganisms have continued growth and reproduction functions.

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.

Antibody immobilization using pneumatic spray: comparison with the avidin-biotin bridge immobilization method.

PubMed

Figueroa, Jhon; Magaña, Sonia; Lim, Daniel V; Schlaf, Rudy

2012-12-14

The formation of a thin antibody film on a glass surface using pneumatic spray was investigated as a potential immobilization technique for capturing pathogenic targets. Goat-Escherichia coli O157:H7 IgG films were made by pneumatic spray and compared against the avidin-biotin bridge immobilized films by assaying with green fluorescent protein (GFP) transformed E. coli O157:H7 cells and fluorescent reporter antibodies. Functionality, stability, and immobilization of the films were tested. The pneumatic spray films had lower fluorescence intensity values than the avidin-biotin bridge films but resulted in similar detection for E. coli O157:H7 at 10(5)-10(7)cells/ml sample concentrations with no detection of non-E. coli O157:H7 strains. Both methods also resulted in similar percent capture efficiencies. The results demonstrated that immobilization of antibody via pneumatic spray did not render the antibody non-functional and produced stable antibody films. The amount of time necessary for immobilization of the antibody was reduced significantly from 24h for the avidin-biotin bridge to 7 min using the pneumatic spray technique, with additional benefits of greatly reduced use of materials and chemicals. The pneumatic spray technique promises to be an alternative for the immobilization of antibodies on glass slides for capturing pathogenic targets and use in biosensor type devices. Copyright © 2012. Published by Elsevier B.V.

Trypsin inhibitor screening in traditional Chinese medicine by using an immobilized enzyme microreactor in capillary and molecular docking study.

PubMed

Cheng, Mengxia; Chen, Zilin

2017-08-01

A trypsin immobilized enzyme microreactor was successfully prepared in capillary for studying enzyme kinetics of trypsin and online screening of trypsin inhibitors from traditional Chinese medicine through capillary electrophoresis. Trypsin was immobilized on the inner wall at the inlet of the capillary treated with polydopamine. The rest of the capillary was used as a separation channel. The parameters including the separation efficiency and the activity of immobilized trypsin were comprehensively evaluated. Under the optimal conditions, online screening of trypsin inhibitors each time can be carried out within 6 min. The Michaelis-Menten constant of immobilized trypsin was calculated to be 0.50 mM, which indicated high affinity of the immobilized trypsin for the substrate. The half-maximal inhibitory concentration of known inhibitor of benzamidine hydrochloride hydrate as a model inhibitor was 13.32 mM. The proposed method was successfully applied to screen trypsin inhibitors from 15 compounds of traditional Chinese medicine. It has been found that baicalin showed inhibitory potency. Molecular docking study well supported the experimental result by exhibiting molecular interaction between enzyme and inhibitors. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

A noble technique a using force-sensing resistor for immobilization-device quality assurance: A feasibility study

NASA Astrophysics Data System (ADS)

Cho, Min-Seok; Kim, Tae-Ho; Kang, Seong-Hee; Kim, Dong-Su; Kim, Kyeong-Hyeon; Shin, Dong-Seok; Noh, Yu-Yun; Koo, Hyun-Jae; Cheon, Geum Seong; Suh, Tae Suk; Kim, Siyong

2016-03-01

Many studies have reported that a patient can move even when an immobilization device is used. Researchers have developed an immobilization-device quality-assurance (QA) system that evaluates the validity of immobilization devices. The QA system consists of force-sensing-resistor (FSR) sensor units, an electric circuit, a signal conditioning device, and a control personal computer (PC) with in-house software. The QA system is designed to measure the force between an immobilization device and a patient's skin by using the FSR sensor unit. This preliminary study aimed to evaluate the feasibility of using the QA system in radiation-exposure situations. When the FSR sensor unit was irradiated with a computed tomography (CT) beam and a treatment beam from a linear accelerator (LINAC), the stability of the output signal, the image artifact on the CT image, and changing the variation on the patient's dose were tested. The results of this study demonstrate that this system is promising in that it performed within the error range (signal variation on CT beam < 0.30 kPa, root-mean-square error (RMSE) of the two CT images according to presence or absence of the FSR sensor unit < 15 HU, signal variation on the treatment beam < 0.15 kPa, and dose difference between the presence and the absence of the FSR sensor unit < 0.02%). Based on the obtained results, we will volunteer tests to investigate the clinical feasibility of the QA system.

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.

Preparation, characterization, and luminescence of (SBA-15) immobilized pepsin

NASA Astrophysics Data System (ADS)

Zhai, Qing-Zhou; Sun, Si-Jia

2014-12-01

SBA-15 mesoporous silica was synthesized by hydrothermal method and its surface was methylated by treatment with methyltrimethoxysilane. Pepsin was immobilized on the obtained materials giving host-guest composite materials (SBA-15)-pepsin and (methylated SBA-15)-pepsin. The optimum conditions for preparation of these materials were established. Methylated SBA-15 (M-SBA-15) has improved immobilization efficiency of enzyme compared to initial SBA-15 silica. It was shown that with the gradual increase of NaCl solution ionic strength the immobilized amount of enzyme was reduced. Powder X-ray diffraction and Fourier transform infrared spectroscopy showed that the host frameworks in the prepared host-guest composite materials are intact and the ordered structure was retained. Scanning electron microscopic studies revealed fibrous morphologic characteristics of the SBA-15 and the immobilized pepsin composite materials. The average particle diameter of (SBA-15)-pepsin composite was 338 ± 10 and 343 ± 10 nm for (M-SBA-15)-pepsin. The low temperature N2 adsorption-desorption study at 77 K showed that the pore sizes and specific surface areas of the host-guest composite materials were smaller than those before the introduction of the enzyme, suggesting that the immobilized enzyme occupied a definite position in the host material pore channels. The UV-vis solid diffuse reflectance and luminescence studies showed that the enzyme was successfully immobilized on to the host material and that after the immobilization of enzyme on SBA-15 the conformation of pepsin macromolecule has not been changed.

Halloysite Clay Nanotubes for Enzyme Immobilization.

PubMed

Tully, Joshua; Yendluri, Raghuvara; Lvov, Yuri

2016-02-08

Halloysite clay is an aluminosilicate nanotube formed by rolling flat sheets of kaolinite clay. They have a 15 nm lumen, 50-70 nm external diameter, length of 0.5-1 μm, and different inside/outside chemistry. Due to these nanoscale properties, they are used for loading, storage, and controlled release of active chemical agents, including anticorrosions, biocides, and drugs. We studied the immobilization in halloysite of laccase, glucose oxidase, and lipase. Overall, negatively charged proteins taken above their isoelectric points were mostly loaded into the positively charged tube's lumen. Typical tube loading with proteins was 6-7 wt % from which one-third was released in 5-10 h and the other two-thirds remained, providing enhanced biocatalysis in nanoconfined conditions. Immobilized lipase showed enhanced stability at acidic pH, and the optimum pH shifted to more alkaline pH. Immobilized laccase was more stable with respect to time, and immobilized glucose oxidase showed retention of enzymatic activity up to 70 °C, whereas the native sample was inactive.

Immobilized Cell Research

DTIC Science & Technology

1990-10-31

specifically with the biotech nologi cal side of cellular immobilization, there aje aspects of this research that have importance in other fields. 20 C...meetings dealt lem facing the Navy. The techniques reviewed here specifically with the biotechnological side of cellular im- should be of particular...phenomena. types of organisms, and the many techniques used to compare cellular physiologies. Undoubtedly, any tech- Why Use Immobilized Cells in

Useful oriented immobilization of antibodies on chimeric magnetic particles: direct correlation of biomacromolecule orientation with biological activity by AFM studies.

PubMed

Marciello, Marzia; Filice, Marco; Olea, David; Velez, Marisela; Guisan, José M; Mateo, Cesar

2014-12-16

The preparation and performance of a suitable chimeric biosensor based on antibodies (Abs) immobilized on lipase-coated magnetic particles by means of a standing orienting strategy are presented. This novel system is based on hydrophobic magnetic particles coated with modified lipase molecules able to orient and further immobilize different Abs in a covalent way without any previous site-selective chemical modification of biomacromolecules. Different key parameters attending the process were studied and optimized. The optimal preparation was performed using a controlled loading (1 nmol Ab g(-1) chimeric support) at pH 9 and a short reaction time to recover a biological activity of about 80%. AFM microscopy was used to study and confirm the Abs-oriented immobilization on lipase-coated magnetic particles and the final achievement of a highly active and recyclable chimeric immune sensor. This direct technique was demonstrated to be a powerful alternative to the indirect immunoactivity assay methods for the study of biomacromolecule-oriented immobilizations.

Polymer-assisted iron oxide magnetic nanoparticle immobilized keratinase

NASA Astrophysics Data System (ADS)

Konwarh, Rocktotpal; Karak, Niranjan; Rai, Sudhir Kumar; Mukherjee, Ashis Kumar

2009-06-01

Nanotechnology holds the prospect for avant-garde changes to improve the performance of materials in various sectors. The domain of enzyme biotechnology is no exception. Immobilization of industrially important enzymes onto nanomaterials, with improved performance, would pave the way to myriad application-based commercialization. Keratinase produced by Bacillus subtilis was immobilized onto poly(ethylene glycol)-supported Fe3O4 superparamagnetic nanoparticles. The optimization process showed that the highest enzyme activity was noted when immobilized onto cyanamide-activated PEG-assisted MNP prepared under conditions of 25 °C and pH 7.2 of the reaction mixture before addition of H2O2 (3% w/w), 2% (w/v) PEG6000 and 0.062:1 molar ratio of PEG to FeCl2·4H2O. Further statistical optimization using response surface methodology yielded an R2 value that could explain more than 94% of the sample variations. Along with the magnetization studies, the immobilization of the enzyme onto the PEG-assisted MNP was characterized by UV, XRD, FTIR and TEM. The immobilization process had resulted in an almost fourfold increase in the enzyme activity over the free enzyme. Furthermore, the immobilized enzyme exhibited a significant thermostability, storage stability and recyclability. The leather-industry-oriented application of the immobilized enzyme was tested for the dehairing of goat-skin.

Estimation of the failure risk of a maxillary premolar with different crack depths with endodontic treatment by computer-aided design/computer-aided manufacturing ceramic restorations.

PubMed

Lin, Chun-Li; Chang, Yen-Hsiang; Hsieh, Shih-Kai; Chang, Wen-Jen

2013-03-01

This study evaluated the risk of failure for an endodontically treated premolar with different crack depths, which was shearing toward the pulp chamber and was restored by using 3 different computer-aided design/computer-aided manufacturing ceramic restoration configurations. Three 3-dimensional finite element models designed with computer-aided design/computer-aided manufacturing ceramic onlay, endocrown, and conventional crown restorations were constructed to perform simulations. The Weibull function was incorporated with finite element analysis to calculate the long-term failure probability relative to different load conditions. The results indicated that the stress values on the enamel, dentin, and luting cement for endocrown restorations exhibited the lowest values relative to the other 2 restoration methods. Weibull analysis revealed that the overall failure probabilities in a shallow cracked premolar were 27%, 2%, and 1% for the onlay, endocrown, and conventional crown restorations, respectively, in the normal occlusal condition. The corresponding values were 70%, 10%, and 2% for the depth cracked premolar. This numeric investigation suggests that the endocrown provides sufficient fracture resistance only in a shallow cracked premolar with endodontic treatment. The conventional crown treatment can immobilize the premolar for different cracked depths with lower failure risk. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Protein immobilization onto various surfaces using a polymer-bound isocyanate

NASA Astrophysics Data System (ADS)

Kang, Hyun-Jin; Cha, Eun Ji; Park, Hee-Deung

2015-01-01

Silane coupling agents have been widely used for immobilizing proteins onto inorganic surfaces. However, the immobilization method using silane coupling agents requires several treatment steps, and its application is limited to only surfaces containing hydroxyl groups. The aim of this study was to develop a novel method to overcome the limitations of the silane-based immobilization method using a polymer-bound isocyanate. Initially, polymer-bound isocyanate was dissolved in organic solvent and then was used to dip-coat inorganic surfaces. Proteins were then immobilized onto the dip-coated surfaces by the formation of urea bonds between the isocyanate groups of the polymer and the amine groups of the protein. The reaction was verified by FT-IR in which NCO stretching peaks disappeared, and CO and NH stretching peaks appeared after immobilization. The immobilization efficiency of the newly developed method was insensitive to reaction temperatures (4-50 °C), but the efficiency increased with reaction time and reached a maximum after 4 h. Furthermore, the method showed comparable immobilization efficiency to the silane-based immobilization method and was applicable to surfaces that cannot form hydroxyl groups. Taken together, the newly developed method provides a simple and efficient platform for immobilizing proteins onto surfaces.

Immobilized fluid membranes for gas separation

DOEpatents

Liu, Wei; Canfield, Nathan L; Zhang, Jian; Li, Xiaohong Shari; Zhang, Jiguang

2014-03-18

Provided herein are immobilized liquid membranes for gas separation, methods of preparing such membranes and uses thereof. In one example, the immobilized membrane includes a porous metallic host matrix and an immobilized liquid fluid (such as a silicone oil) that is immobilized within one or more pores included within the porous metallic host matrix. The immobilized liquid membrane is capable of selective permeation of one type of molecule (such as oxygen) over another type of molecule (such as water). In some examples, the selective membrane is incorporated into a device to supply oxygen from ambient air to the device for electrochemical reactions, and at the same time, to block water penetration and electrolyte loss from the device.

Immobilized metal ion affinity electrophoresis. A study with several model proteins containing histidine.

PubMed

Goubran-Botros, H; Nanak, E; Abdul Nour, J; Birkenmeir, G; Vijayalakshmi, M A

1992-04-24

Immobilized metal ion affinity electrophoresis (IMA-Elec) is one among the many methods derived from the immobilized metal ion affinity chromatography. Two approaches for incorporating the metal ligand, were studied. One was in the form of insoluble particulate material based on Sepharose 6B and the other in the form of soluble polymer based on polyethylene glycol (PEG) 5000. Both the polymers coupled with iminodiacetate and metallized with copper or zinc were used as ligands, incorporated into soluble agarose as the electrophoretic gel. Several histidine-containing model proteins were studied with both the systems and their metal binding strengths were determined as the dissociation constants, Kd. The results clearly demonstrated that the mechanism of protein recognition by immobilized copper or zinc via the accessible histidyl residues was maintained in the IMA-Elec system. Proteins with increasing numbers of histidine residues showed increasing binding strength (lower Kd values). While this basic mechanism was conserved, the supporting polymers (Sepharose 6B and the PEG 5000) showed significant differences in the metal binding to the protein. The polysaccharide Sepharose 6B enhanced the binding strength compared with PEG 5000. The optimum electrophoretic parameters were determined to be current intensities up to 20 mA and pH ca. 7.0. At pH greater than 8.0, a significant decrease in the affinity was observed, this decrease being greater with PEG 5000 than Sepharose 6B as supporting material.

Enhanced enzyme stability through site-directed covalent immobilization.

PubMed

Wu, Jeffrey Chun Yu; Hutchings, Christopher Hayden; Lindsay, Mark Jeffrey; Werner, Christopher James; Bundy, Bradley Charles

2015-01-10

Breakthroughs in enzyme immobilization have enabled increased enzyme recovery and reusability, leading to significant decreases in the cost of enzyme use and fueling biocatalysis growth. However, current enzyme immobilization techniques suffer from leaching, enzyme stability, and recoverability and reusability issues. Moreover, these techniques lack the ability to control the orientation of the immobilized enzymes. To determine the impact of orientation on covalently immobilized enzyme activity and stability, we apply our PRECISE (Protein Residue-Explicit Covalent Immobilization for Stability Enhancement) system to a model enzyme, T4 lysozyme. The PRECISE system uses non-canonical amino acid incorporation and the Huisgen 1,3-dipolar cycloaddition "click" reaction to enable directed enzyme immobilization at rationally chosen residues throughout an enzyme. Unlike previous site-specific systems, the PRECISE system is a truly covalent immobilization method. Utilizing this system, enzymes immobilized at proximate and distant locations from the active site were tested for activity and stability under denaturing conditions. Our results demonstrate that orientation control of covalently immobilized enzymes can provide activity and stability benefits exceeding that of traditional random covalent immobilization techniques. PRECISE immobilized enzymes were 50 and 73% more active than randomly immobilized enzymes after harsh freeze-thaw and chemical denaturant treatments. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of immobilization on spermiogenesis

NASA Technical Reports Server (NTRS)

Meitner, E. R.

1980-01-01

The influence of immobilization stress on spermiogenesis in rats was investigated. After 96 hour immobilization, histological changes began to manifest themselves in the form of practically complete disappearance of cell population of the wall of seminiferous tubule as well as a markedly increased number of cells with pathologic mitoses. Enzymological investigations showed various changes of activity (of acid and alkaline phosphatase and nonspecific esterase) in the 24, 48, and 96 hour immobilization groups.

Removal of acetaminophen in water by laccase immobilized in barium alginate.

PubMed

Ratanapongleka, Karnika; Punbut, Supot

2018-02-01

This research has focused on the optimization of immobilized laccase condition and utilization in degradation of acetaminophen contaminated in aqueous solution. Laccase from Lentinus polychrous was immobilized in barium alginate. The effects of laccase immobilization such as sodium alginate concentration, barium chloride concentration and gelation time were studied. The optimal conditions for immobilization were sodium alginate 5% (w/v), barium chloride 5% (w/v) and gelation time of 60 min. Immobilized laccase was then used for acetaminophen removal. Acetaminophen was removed quickly in the first 50 min. The degradation rate and percentage of removal increased when the enzyme concentration increased. Immobilized laccase at 0.57 U/g-alginate showed the maximum removal at 94% in 240 min. The removal efficiency decreased with increasing initial acetaminophen concentration. The K m value for immobilized laccase (98.86 µM) was lower than that of free laccase (203.56 µM), indicating that substrate affinity was probably enhanced by immobilization. The immobilized enzyme exhibited high activity and good acetaminophen removal at pH 7 and temperature of 35°C. The activation energies of free and immobilized laccase for degradation of acetaminophen were 8.08 and 17.70 kJ/mol, respectively. It was also found that laccase stability to pH and temperature increased after immobilization. Furthermore, immobilized laccase could be reused for five cycles. The capability of removal and enzyme activity were retained above 70%.

Visible and UV-curable chitosan derivatives for immobilization of biomolecules.

PubMed

Kim, Eun-Hye; Han, Ga-Dug; Kim, Jae-Won; Noh, Seung-Hyun; Lee, Jae-Gwan; Ito, Yoshihiro; Son, Tae-Il

2017-11-01

Chitosan, which has many biocompatible properties, is used widely in medical field like wound healing, drug delivery and so on. Chitosan could be used as a biomaterial to immobilize protein-drug. There are many methods to immobilize protein-drug, but they have some drawbacks such as low efficiency and denaturation of protein. Therefore, photo-immobilization method is suggested to immobilize protein-drug. Photo-immobilization method is simple-reaction and also needs no additional crosslinking reagent. There has been some effort to modify chitosan to have an ability of photo-immobilization. Generally, visible and UV light reactive chitosan derivatives were prepared. Various types of photo-curable chitosan derivatives showed possibility for application to medical field. For example, they showed ability for protein-immobilization and some of them showed wound-healing effect, anti-adhesive effect, or property to interact directly with titanium surface. In this study, we introduce many types of photo-curable chitosan derivative and their possibility of medical application. Copyright © 2017 Elsevier B.V. All rights reserved.

Heavy metal removal by caustic-treated yeast immobilized in alginate

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

Lu, Y.; Wilkins, E.

1995-12-31

Saccharomyces cerevisiae yeast biomass was treated with hot alkali to increase its biosorption capacity for heavy metals and then was immobilized in alginate gel. Biosorption capacities for Cu{sup 2+}, Cd{sup 2+}, and Zn{sup 2+} on alginate gel, native yeast, native yeast immobilized in alginate gel, and caustic-treated yeast immobilized in alginate gel were all compared. Immobilized yeasts could be reactivated and reused in a manner similar to the ion exchange resins. Immobilized caustic-treated yeast has high heavy metal biosorption capacity and high metal removal efficiency in a rather wide acidic pH region. The biosorption isotherm of immobilized caustic-treated yeast wasmore » studied, and empirical equations were obtained. The initial pH of polluted water affected the metal removal efficiency significantly, and the equilibrium biosorption capacity seemed to be temperature independent at lower initial metal concentrations.« less

Thrombin immobilization to methacrylic acid grafted poly(3-hydroxybutyrate) and its in vitro application.

PubMed

Akkaya, Alper; Pazarlioglu, Nurdan

2013-01-01

Poly(3-hydroxybutyrate) is nontoxic and biodegradable, with good biocompatibility and potential support for long-term implants. For this reason, it is a good support for enzyme immobilization. Enzyme immobilization could not be done directly because poly(3-hydroxybutyrate) has no functional groups. Therefore, modification should be done for enzyme immobilization. In this study, methacrylic acid was graft polymerized to poly(3-hydroxybutyrate) and thrombin was immobilized to polymethacrylic acid grafted poly(3-hydroxybutyrate). In fact, graft polymerization of methacrylic acid to poly(3-hydroxybutyrate) and thrombin immobilization was a model study. Biomolecule immobilized poly(3-hydroxybutyrate) could be used as an implant. Thrombin was selected as a biomolecule for this model study and it was immobilized to methacrylic acid grafted poly(3-hydroxybutyrate). Then the developed product was used to stop bleeding.

An approach for liposome immobilization using sterically stabilized micelles (SSMs) as a precursor for bio-layer interferometry-based interaction studies.

PubMed

Wallner, Jakob; Lhota, Gabriele; Schosserer, Markus; Vorauer-Uhl, Karola

2017-06-01

Non-fluidic bio-layer interferometry (BLI) has rapidly become a standard tool for monitoring almost all biomolecular interactions in a label-free, real-time and high-throughput manner. High-efficiency screening methods which measure the kinetics of liposomes with a variety of compounds require the immobilization of liposomes. In this work, a method is described for immobilizing liposomes for interaction studies, based on the biophysical principles of this biosensor platform. The immobilization approach includes the loading of DSPE-PEG (2000) -biotin containing sterically stabilized micelles (SSMs) which are restructured in a buffer change step, resulting in an accessible substrate for liposome immobilization. Liposomes in a concentration of 5mM of varying composition and fluidity were immobilized on the sensor surface by inserting the hydrophobic residues of the former loaded SSMs. This proof of principle was carried out using Cytochrome C as a membrane-interacting model protein. The binding of Cytochrome C to the immobilized liposomes was demonstrated, and the derived kinetic and affinity constants were similar to values given in the literature. In order to obtain a detailed understanding of this surface, and to show the integrity of the liposomes, confocal fluorescence microscopy was used. Images of immobilized liposomes containing calcein in the aqueous core indicated intact vesicles. A combination of this simple liposome immobilization approach, the possibility of automation on BLI systems with high throughput within an acceptable timescale and excellent reproducibility makes this assay suitable for basic research as well as for industrial and regulatory applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Characteristics of pectinase treated with ultrasound both during and after the immobilization process.

PubMed

Ma, Xiaobin; Wang, Danli; Yin, Michelle; Lucente, Juliet; Wang, Wenjun; Ding, Tian; Ye, Xingqian; Liu, Donghong

2017-05-01

In this study, ultrasound was applied both during and after the immobilization process and characteristics of different immobilized pectinase samples were studied. When introduced during the immobilization process, ultrasound at an intensity of 9WmL -1 for 20min increased the immobilization yield 92.28% more than the control. When introduced to the already immobilized pectinase, ultrasound at an intensity of 4.5WmL -1 for 10min increased the pectinase activity by 30.05%. Results of scanning electron microscope demonstrated that ultrasound increased surface area and loosened structures of immobilized enzymes. Higher V max and lower K m were obtained after ultrasound treatment, indicating the increased catalytic efficiency and enhanced affinity of immobilized pectinase. Furthermore, the optimum temperature and pH for free and immobilized pectinase remained unchanged at 50°C and pH 4. Thermostability, reaction stability and reusability of two ultrasound-treated pectinase enzymes slightly decreased due to structural matrix changes. Copyright © 2016 Elsevier B.V. All rights reserved.

Immobilization of ionophore and surface characterization studies of the titanium(III) ion in a PVC-membrane sensor.

PubMed

Rezayi, Majid; Heng, Lee Yook; Kassim, Anuar; Ahmadzadeh, Saeid; Abdollahi, Yadollah; Jahangirian, Hossein

2012-01-01

Novel ionophores comprising various hydroxide and amine structures were immobilized onto poly(vinyl chloride) (PVC) matrices, and these were examined to determine Ti(III) selectivity. To predict the selectivity of Ti(III), a PVC membrane was used to investigate the binding of Ti(III) to c-methylcalix[4]resorcinarene (CMCR). The study showed that the chelating ligand, CMCR, was coordinated selectively to Ti(III) at eight coordination sites involving the oxygen atoms at the interface of the membrane/solution. The membrane was prepared, based on CMCR as an ionophore, sodium tetrakis(4-fluorophenyl) borate (NaTFPB) as a lipophilic ionic additive, and dioctylphthalate (DOP) as a plasticizer. The immobilization of the ionophore and surface characterization studies revealed that the performance of CMCR-immobilized PVC was equivalent to that of mobile ionophores in supported liquid membranes (SLMs). The strengths of the ion-ionophore (CMCR-Ti(OH)(OH(2))(5) (2+)) interactions and the role of ionophores on membranes were studied via UV-Vis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and and X-ray diffraction (XRD).

Biodiesel production with immobilized lipase: A review.

PubMed

Tan, Tianwei; Lu, Jike; Nie, Kaili; Deng, Li; Wang, Fang

2010-01-01

Fatty acid alkyl esters, also called biodiesel, are environmentally friendly and show great potential as an alternative liquid fuel. Biodiesel is produced by transesterification of oils or fats with chemical catalysts or lipase. Immobilized lipase as the biocatalyst draws high attention because that process is "greener". This article reviews the current status of biodiesel production with immobilized lipase, including various lipases, immobilization methods, various feedstocks, lipase inactivation caused by short chain alcohols and large scale industrialization. Adsorption is still the most widely employed method for lipase immobilization. There are two kinds of lipase used most frequently especially for large scale industrialization. One is Candida antartica lipase immobilized on acrylic resin, and the other is Candida sp. 99-125 lipase immobilized on inexpensive textile membranes. However, to further reduce the cost of biodiesel production, new immobilization techniques with higher activity and stability still need to be explored. Copyright 2010 Elsevier Inc. All rights reserved.

Comparative study of 6-APA production by free and agar immobilized bacteria in nutrient broth culture.

PubMed

Dolui, A K; Das, S

2011-04-01

In the present study different bacterial samples were isolated from soil of different places of Dibrugarh and screened for biotransformation ability to produce 6-Aminopenicillanic acid. Among ten isolated bacterial samples, three gram positive bacterial samples designated as AKDD-2, AKDD-4 and AKDD-6 showed the production of 6-APA from penicillin G. Assessment of production of 6-APA after incubation in penicillin G (2 mg/ml) by three different samples separately in free and agar immobilization state was done by HPLC analysis. Reusability of immobilized cells was found successful up to 14 days.

Immobilized Kluyveromyces marxianus cells in carboxymethyl cellulose for production of ethanol from cheese whey: experimental and kinetic studies.

PubMed

Roohina, Fatemeh; Mohammadi, Maedeh; Najafpour, Ghasem D

2016-09-01

Cheese whey fermentation to ethanol using immobilized Kluyveromyces marxianus cells was investigated in batch and continuous operation. In batch fermentation, the yeast cells were immobilized in carboxymethyl cellulose (CMC) polymer and also synthesized graft copolymer of CMC with N-vinyl-2-pyrrolidone, denoted as CMC-g-PVP, and the efficiency of the two developed cell entrapped beads for lactose fermentation to ethanol was examined. The yeast cells immobilized in CMC-g-PVP performed slightly better than CMC with ethanol production yields of 0.52 and 0.49 g ethanol/g lactose, respectively. The effect of supplementation of cheese whey with lactose (42, 70, 100 and 150 g/l) on fermentative performance of K. marxianus immobilized in CMC beads was considered and the results were used for kinetic studies. The first order reaction model was suitable to describe the kinetics of substrate utilization and modified Gompertz model was quite successful to predict the ethanol production. For continuous ethanol fermentation, a packed-bed immobilized cell reactor (ICR) was operated at several hydraulic retention times; HRTs of 11, 15 and 30 h. At the HRT of 30 h, the ethanol production yield using CMC beads was 0.49 g/g which implies that 91.07 % of the theoretical yield was achieved.

Incidence of and risk factors for complications associated with halo-vest immobilization: a prospective, descriptive cohort study of 239 patients.

PubMed

van Middendorp, Joost J; Slooff, Willem-Bart M; Nellestein, W Ronald; Oner, F Cumhur

2009-01-01

Since high rates of serious complications, such as death and pneumonia, during halo-vest immobilization have been reported, there has been a tendency of restraint with regard to the use of the halo vest. However, the rate of complications in a high-volume center with sufficient experience is unknown. Our objective was to determine the incidence of and risk factors associated with complications during halo-vest immobilization. During a five-year period, a prospective cohort study was performed in a single, level-I trauma center that was also a tertiary referral center for spinal disorders. Data from all patients undergoing halo-vest immobilization were collected prospectively, and every complication was recorded. The primary outcome was the presence or absence of complications. Univariate regression analysis and regression modeling were used to analyze the results. In 239 patients treated with halo-vest immobilization, twenty-six major, seventy-two intermediate, and 121 minor complications were observed. Fourteen patients (6%) died during the treatment, although only one death was related directly to the immobilization and three were possibly related directly to the immobilization. Twelve patients (5%) acquired pneumonia during halo-vest immobilization. Patients older than sixty-five years did not have an increased risk of pneumonia (p = 0.543) or halo vest-related mortality (p = 0.467). Halo vest-related complications ranged from three patients (1%) with incorrect initial placement of the halo vest to twenty-nine patients (12%) with a pin-site infection. Pin-site infection was significantly related to pin penetration through the outer table of the skull (odds ratio, 4.34; 95% confidence interval, 1.22 to 15.51; p = 0.024). In 164 trauma patients treated only with halo-vest immobilization, cervical fractures with facet joint involvement or dislocations were significantly related to radiographic loss of alignment during follow-up (odds ratio, 2.81; 95% confidence

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.

[Immobilization of pectawamorine G10x on silichromes].

PubMed

Bogatskiĭ, A V; Davidenko, T I; Gren', T A

1980-01-01

Immobilization of pectawamorine G10x on silochromes, using cyanuric chloride, 2,4-toluylene diisocyanate, glutaric dialdehyde, thionyl chloride, phosphorus tribromide, titanium tetrachloride, zirconium oxychloride and hafnium oxychloride was studied. The use of glutaric dialdehyde assured the strongest binding and the preatest stability of activity. Properties of the native pectawamorine G10x and immobilized preparations were studied on a comparative basis. Pectawamorine G10x immobilized by means of hafnium oxychloride showed increased stability when stored at 5 degrees C and used repeatedly. In every case, except for cyanuric chloride and glutaric dialdehyde, maximum activity was at a temperature 10 degrees C higher than for the native enzyme, and optimum pH varied for the preparations with different binding reagents.

Study of acetic acid production by immobilized acetobacter cells: oxygen transfer

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

Ghommidh, C.; Navarro, J.M.; Durand, G.

1982-03-01

The immobilization of living Acetobacter cells by adsorption onto a large-surface-area ceramic support was studied in a pulsed flow reactor. The high oxygen transfer capability of the reactor enabled acetic acid production rates up to 10.4 g/L/h to be achieved. Using a simple mathematical model incorporating both internal and external mass transfer coefficients, it was shown that oxygen transfer in the microbial film controls the reactor productivity. (Refs. 10).

Effects of acoustic wave resonance oscillation on immobilized enzyme

NASA Astrophysics Data System (ADS)

Nishiyama, Hiroshi; Watanabe, Tomoya; Inoue, Yasunobu

2014-03-01

In aiming at developing a new method to artificially activate enzyme catalysts immobilized on surface, the effects of resonance oscillation of bulk acoustic waves were studied. Glucose oxidase (GOD) was immobilized by a covalent coupling method on a ferroelectric lead zirconate titanate (PZT) device that was able to generate thickness-extensional resonance oscillation (TERO). Glucose oxidation by the GOD enzyme was studied in a microreactor. The generation of TERO immediately increased the catalytic activity of immobilized GOD by a factor of 2-3. With turn-off of TERO, no significant activity decrease occurred, and 80-90% of the enhanced activity was maintained while the reaction proceeded. The almost complete reversion of the activity to the original low level before TERO generation was observed when the immobilized GOD was exposed to a glucose substrate-free solution. These results indicated that the presence of glucose substrate was essential for TERO-induced GOD activation and preservation of the increased activity level. The influences of reaction temperature, glucose concentration, pH, and rf electric power on the TERO activation showed that TERO strengthened the interactions of the immobilized enzyme with glucose substrate and hence promoted the formation of an activation complex.

Optimization of pectinase immobilization on grafted alginate-agar gel beads by 24 full factorial CCD and thermodynamic profiling for evaluating of operational covalent immobilization.

PubMed

Abdel Wahab, Walaa A; Karam, Eman A; Hassan, Mohamed E; Kansoh, Amany L; Esawy, Mona A; Awad, Ghada E A

2018-07-01

Pectinase produced by a honey derived from the fungus Aspergillus awamori KX943614 was covalently immobilized onto gel beads made of alginate and agar. Polyethyleneimine, glutaraldehyde, loading time and enzyme's units were optimized by 2 4 full factorial central composite design (CCD). The immobilization process increased the optimal working pH for the free pectinase from 5 to a broader range of pH4.5-5.5 and the optimum operational temperature from 55°C to a higher temperature, of 60°C, which is favored to reduce the enzyme's microbial contamination. The thermodynamics studies showed a thermal stability enhancement against high temperature for the immobilized formula. Moreover, an increase in half-lives and D-values was achieved. The thermodynamic studies proved that immobilization of pectinase made a remarkable increase in enthalpy and free energy because of enzyme stability enhancement. The reusability test revealed that 60% of pectinase's original activity was retained after 8 successive cycles. This gel formula may be convenient for immobilization of other industrial enzymes. Copyright © 2018 Elsevier B.V. All rights reserved.

Immobilization of pectin depolymerising polygalacturonase using different polymers.

PubMed

Ur Rehman, Haneef; Aman, Afsheen; Nawaz, Muhammad Asif; Karim, Asad; Ghani, Maria; Baloch, Abdul Hameed; Ul Qader, Shah Ali

2016-01-01

Polygalacturonase catalyses the hydrolysis of pectin substances and widely has been used in food and textile industries. In current study, different polymers such as calcium alginate beads, polyacrylamide gel and agar-agar matrix were screened for the immobilization of polygalacturonase through entrapment technique. Polyacrylamide gel was found to be most promising one and gave maximum (89%) immobilization yield as compared to agar-agar (80%) and calcium alginate beads (46%). The polymers increased the reaction time of polygalacturonase and polymers entrapped polygalacturonases showed maximum pectinolytic activity after 10 min of reaction as compared to free polygalacturonase which performed maximum activity after 5.0 min of reaction time. The temperature of polygalacturonase for maximum enzymatic activity was increased from 45°C to 50°C and 55°C when it was immobilized within agar-agar and calcium alginate beads, respectively. The optimum pH (pH 10) of polygalacturonase was remained same when it was immobilized within polyacrylamide gel and calcium alginate beads, but changed from pH 10 to pH 9.0 after entrapment within agar-agar. Thermal stability of polygalacturonase was improved after immobilization and immobilized polygalacturonases showed higher tolerance against different temperatures as compared to free enzyme. Polymers entrapped polygalacturonases showed good reusability and retained more than 80% of their initial activity during 2nd cycles. Copyright © 2015 Elsevier B.V. All rights reserved.

Immobilization of flavan-3-ols onto sensor chips to study their interactions with proteins and pectins by SPR

NASA Astrophysics Data System (ADS)

Watrelot, Aude A.; Tran, Dong Tien; Buffeteau, Thierry; Deffieux, Denis; Le Bourvellec, Carine; Quideau, Stéphane; Renard, Catherine M. G. C.

2016-05-01

Interactions between plant polyphenols and biomacromolecules such as proteins and pectins have been studied by several methods in solution (e.g. isothermal titration calorimetry, dynamic light scattering, nuclear magnetic resonance and spectrophotometry). Herein, these interactions were investigated in real time by Surface Plasmon Resonance (SPR) analysis after immobilization of flavan-3-ols onto a sensor chip surface. (-)-epicatechin, (+)-catechin and flavan-3-ol oligomers with an average degree of polymerization of 2 and 8 were chemically modified using N-(2-(tritylthio)ethyl)propiolamide in order to introduce a spacer unit onto the catecholic B ring. Modified flavan-3-ols were then immobilized onto a carboxymethylated dextran surface (CM5). Immobilization was validated and further verified by evaluating flavan-3-ol interaction with bovine serum albumin (BSA), poly-L-proline or commercial pectins. BSA was found to have a stronger association with monomeric flavan-3-ols than oligomers. SPR analysis of selected flavan-3-ols immobilized onto CM5 sensor chips showed a stronger association for citrus pectins than apple pectins, regardless of flavan-3-ol degree of polymerization.

Knowledge levels of pre-school teachers related with basic first-aid practices, Isparta sample.

PubMed

Sönmez, Yonca; Uskun, Ersin; Pehlivan, Azize

2014-09-01

The aim of this study was to evaluate the levels of knowledge of pre-school teachers working in the province center of Isparta related with basic first-aid practices and some factors which affected these levels of knowledge. In this cross-sectional, analytic study, 110 pre-school teachers working in the province center of Isparta constituted the population. A questionnaire questioning sociodemographic properties and the level of knowledge related with first-aid practices was applied under supervision. The level of knowledge was evaluated on a 20-point scale. In the analyses, Kruskal-Wallis and Mann-Whitney U tests and Spearman's rank correlation were used. The study was approved by the Ethical Committee for Clinical Studies of Süleyman Demirel University School of Medicine (registration number: 105). The mean score of first-aid knowledge of the pre-school teachers was found to be 11.9±2.9. The least known issues included washing the wound by soap and water after a dog bite, information related with the necessity of immobilization of a child who has fallen from a high level and the phone number of National Poison Information Center (16.4%, 20.9% and 22.7%, respectively). The scores of the subjects whose knowledge of first-aid was evaluated to be well were higher compared to the subjects whose knowledge of first-aid was evaluated to be moderate (p=0.009) and poor (p=0.001). It was found that first-aid scores did not show significant difference in terms of age, working period, having received first-aid training and having faced with a condition requiring first-aid previously (p>0.05, for all comparisons). It was found that pre-school teachers had insufficient first-aid knowledge. Since the first-aid knowledge scores of the subjects who reported that they received first-aid training before did not show significant difference, it was thought that the quality of training was as important as receiving training.

National Postsecondary Student Aid Study: Student Financial Aid Estimates for 1999-2000. E.D. Tabs.

ERIC Educational Resources Information Center

National Center for Education Statistics (ED), Washington, DC.

The National Postsecondary Student Aid Study (NPSAS) is a comprehensive survey that examines how students and their families pay for postsecondary education. The study included nationally representative samples of students, including those who do and do not receive financial aid. This report has been prepared to provide some key estimates as…

Biodegradation and kinetic study of benzene in bioreactor packed with PUF and alginate beads and immobilized with Bacillus sp. M3.

PubMed

Kureel, M K; Geed, S R; Giri, B S; Rai, B N; Singh, R S

2017-10-01

Benzene removal in free and immobilized cells on polyurethane foam (PUF) and polyvinyl alcohol (PVA)-alginate beads was studied using an indigenous soil bacterium Bacillus sp. M3 isolated from petroleum-contaminated soil. The important process parameters (pH, temperature and inoculums size) were optimized and found to be 7, 37°C and 6.0×10 8 CFU/mL, respectively. Benzene removals were observed to be 70, 84 and 90% within 9days in a free cell, immobilized PVA-alginate beads and PUF, respectively under optimum operating conditions. FT-IR and GC-MS analysis confirm the presence of phenol, 1,2-benzenediol, hydroquinone and benzoate as metabolites. The important kinetic parameter ratios (µ max /K s ; L/mg·day ) calculated using Monod model was found to be 0.00123 for free cell, 0.00159 for immobilized alginate beads and 0.002016 for immobilized PUF. Similarly inhibition constants (K i ; mg/L) calculated using Andrew-Haldane model was found to be 435.84 for free cell, 664.25 for immobilized alginate beads and 724.93 for immobilized PUF. Copyright © 2017 Elsevier Ltd. All rights reserved.

Immobilized Lactase in the Biochemistry Laboratory

NASA Astrophysics Data System (ADS)

Allison, Matthew J.; Bering, C. Larry

1998-10-01

Immobilized enzymes have many practical applications. They may be used in clinical, industrial, and biotechnological laboratories and in many clinical diagnostic kits. For educational purposes, use of immobilized enzymes can easily be taught at the undergraduate or even secondary level. We have developed an immobilized enzyme experiment that combines many practical techniques used in the biochemistry laboratory and fits within a three-hour time frame. In this experiment, lactase from over-the-counter tablets for patients with lactose intolerance is immobilized in polyacrylamide, which is then milled into small beads and placed into a chromatography column. A lactose solution is added to the column and the eluant is assayed using the glucose oxidase assay, available as a kit. We have determined the optimal conditions to give the greatest turnover of lactose while allowing the immobilized enzymes to be active for long periods at room temperature.

Cellulase immobilization on magnetic nanoparticles encapsulated in polymer nanospheres.

PubMed

Lima, Janaina S; Araújo, Pedro H H; Sayer, Claudia; Souza, Antonio A U; Viegas, Alexandre C; de Oliveira, Débora

2017-04-01

Immobilization of cellulases on magnetic nanoparticles, especially magnetite nanoparticles, has been the main approach studied to make this enzyme, economically and industrially, more attractive. However, magnetite nanoparticles tend to agglomerate, are very reactive and easily oxidized in air, which has strong impact on their useful life. Thus, it is very important to provide proper surface coating to avoid the mentioned problems. This study aimed to investigate the immobilization of cellulase on magnetic nanoparticles encapsulated in polymeric nanospheres. The support was characterized in terms of morphology, average diameter, magnetic behavior and thermal decomposition analyses. The polymer nanospheres containing encapsulated magnetic nanoparticles showed superparamagnetic behavior and intensity average diameter about 150 nm. Immobilized cellulase exhibited broader temperature stability than in the free form and great reusability capacity, 69% of the initial enzyme activity was maintained after eight cycles of use. The magnetic support showed potential for cellulase immobilization and allowed fast and easy biocatalyst recovery through a single magnet.

Immobilized enzyme studies in a microscale bioreactor.

PubMed

Jones, Francis; Forrest, Scott; Palmer, Jim; Lu, Zonghuan; Elmore, John; Elmore, Bill B

2004-01-01

Novel microreactors with immobilized enzymes were fabricated using both silicon and polymer-based microfabrication techniques. The effectiveness of these reactors was examined along with their behavior over time. Urease enzyme was successfully incorporated into microchannels of a polymeric matrix of polydimethylsiloxane and through layer-bylayer self-assembly techniques onto silicon. The fabricated microchannels had cross-sectional dimensions ranging from tens to hundreds of micrometers in width and height. The experimental results for continuous-flow microreactors are reported for the conversion of urea to ammonia by urease enzyme. Urea conversions of >90% were observed.

Determination of conformation and orientation of immobilized peptides and proteins at buried interfaces

NASA Astrophysics Data System (ADS)

Shen, Lei; Ulrich, Nathan W.; Mello, Charlene M.; Chen, Zhan

2015-01-01

Surface immobilized peptides/proteins have important applications such as antimicrobial coating and biosensing. We report a study of such peptides/proteins using sum frequency generation vibrational spectroscopy and ATR-FTIR. Immobilization on surfaces via physical adsorption and chemical coupling revealed that structures of chemically immobilized peptides are determined by immobilization sites, chemical environments, and substrate surfaces. In addition, controlling enzyme orientation by engineering the surface immobilization site demonstrated that structures can be well-correlated to measured chemical activity. This research facilitates the development of immobilized peptides/proteins with improved activities by optimizing their surface orientation and structure.

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.

Management of immobilization and its complication for elderly.

PubMed

Laksmi, Purwita W; Harimurti, Kuntjoro; Setiati, Siti; Soejono, Czeresna H; Aries, Wanarani; Roosheroe, Arya Govinda

2008-10-01

Increased life expectancy have an effect on the rising percentage of elderly population in Indonesia and health problem associated with the elderly, particularly immobilization. Immobilization may cause various complications, especially when it has been overlooked without any appropriate and proper medical care in keeping with the procedures. High incidence of immobilization in elderly and the life-threatening complication call for an agreement on management of immobilization and its complication. Management of immobilization needs interdisciplinary team-work cooperation, the patients and their family. The management may be commenced through a complete geriatric review, formulating functional goals and constructing therapeutic plan. Various medical conditions and external factors that may act as risk factors of immobilization as well as drugs intake that may exaggerate the immobilization should be evaluated and optimally managed. Any complication due to immobilization and other concomitant disease/condition should be recognized and managed comprehensively in order to reduce morbidity and mortality. Management of immobilization and its complications include pharmacological and non-pharmacological treatment, i.e. various mobility exercises, utilization of ambulatory device and supporting appliance for assisting patients in stand-up position, as well as the management of urinary voiding and defecation.

Covalent immobilization of invertase on PAMAM-dendrimer modified superparamagnetic iron oxide nanoparticles

NASA Astrophysics Data System (ADS)

Uzun, K.; Çevik, E.; Şenel, M.; Sözeri, H.; Baykal, A.; Abasıyanık, M. F.; Toprak, M. S.

2010-10-01

In this study, polyamidoamine (PAMAM) dendrimer was synthesized on the surface of superparamagnetite nanoparticles to enhance invertase immobilization. The amount of immobilized enzyme on the surface-hyperbranched magnetite nanoparticle was up to 2.5 times (i.e., 250%) as much as that of magnetite nanoparticle modified with only amino silane. Maximum reaction rate ( V max) and Michaelis-Menten constant ( K m) were determined for the free and immobilized enzymes. Various characteristics of immobilized invertase such as; the temperature activity, thermal stability, operational stability, and storage stability were evaluated and results revealed that stability of the enzyme is improved upon immobilization.

Immobilization of Paecilomyces variotii tannase and properties of the immobilized enzyme.

PubMed

Schons, Patrícia Fernanda; Lopes, Fernanda Cristina Rezende; Battestin, Vania; Macedo, Gabriela Alves

2011-01-01

Tannase produced by Paecilomyces variotii was encapsulated in sodium alginate beads and used for the effective hydrolysis of tannic acid; the efficiency of hydrolysis was comparable to that of the free enzyme. The alginate beads retained 100% of their efficiency in the first three rounds of successive use and 60% in rounds 4 and 5. The response surface methodology showed that the best conditions to hydrolysis of tannic acid by immobilized tannase were: sodium alginate 5.2%, CaCl₂ 0.55 M and 9 h to curing time. The optimized process resulted in 2.4 times more hydrolysed tannic acid than that obtained before optimization. The optimum pH for the actions of both the encapsulated and the free enzymes was 5.5. The optimum temperature of the reaction was determined to be 40 °C for the free enzyme and 60 °C for the immobilized form. The immobilization process improved the stability at low pH.

The effects of below-elbow immobilization on driving performance.

PubMed

Jones, Evan M; Barrow, Aaron E; Skordas, Nic J; Green, David P; Cho, Mickey S

2017-02-01

There is limited research to guide physicians and patients in deciding whether it is safe to drive while wearing various forms of upper extremity immobilization. The purpose of this study is to evaluate the effect of below-elbow removable splints and fiberglass casts on automobile driving performance. 20 healthy subjects completed 10 runs through a closed, cone-marked driving course while wearing a randomized sequence of four different types of immobilization on each extremity (short arm thumb spica fiberglass cast, short arm fiberglass cast, short arm thumb spica splint, and short arm wrist splint). The first and last driving runs were without immobilization and served as controls. Performance was measured based on evaluation by a certified driving instructor (pass/fail scoring), cones hit, run time, and subject-perceived driving difficulty (1-10 analogue scoring). The greatest number of instructor-scored failures occurred while immobilized in right arm spica casts (n=6; p=0.02) and left arm spica casts (n=5; p=0.049). The right arm spica cast had the highest subject-perceived difficulty (5.2±1.9; p<0.001). All forms of immobilization had significantly increased perceived difficulty compared to control, except for the left short arm splint (2.5±1.6; p>0.05). There was no significant difference in number of cones hit or driving time between control runs and runs with any type of immobilization. Drivers should use caution when wearing any of the forms of upper extremity immobilization tested in this study. All forms of immobilization, with exception of the left short arm splint significantly increased perceived driving difficulty. However, only the fiberglass spica casts (both left and right arm), significantly increased drive run failures due to loss of vehicle control. We recommend against driving when wearing a below-elbow fiberglass spica cast on either extremity. Copyright © 2016. Published by Elsevier Ltd.

Recent developments and applications of immobilized laccase.

PubMed

Fernández-Fernández, María; Sanromán, M Ángeles; Moldes, Diego

2013-12-01

Laccase is a promising biocatalyst with many possible applications, including bioremediation, chemical synthesis, biobleaching of paper pulp, biosensing, textile finishing and wine stabilization. The immobilization of enzymes offers several improvements for enzyme applications because the storage and operational stabilities are frequently enhanced. Moreover, the reusability of immobilized enzymes represents a great advantage compared with free enzymes. In this work, we discuss the different methodologies of enzyme immobilization that have been reported for laccases, such as adsorption, entrapment, encapsulation, covalent binding and self-immobilization. The applications of laccase immobilized by the aforementioned methodologies are presented, paying special attention to recent approaches regarding environmental applications and electrobiochemistry. Copyright © 2012 Elsevier Inc. All rights reserved.

[Growth inhibition effect of immobilized pectinase on Microcystis aeruginosa].

PubMed

Shen, Qing-Qing; Peng, Qian; Lai, Yong-Hong; Ji, Kai-Yan; Han, Xiu-Lin

2012-12-01

To confirm the growth inhibition effect of immobilized pectinase on algae, co-cultivation method was used to investigate the effect of immobilized pectinase on the growth of Microcystis aeruginosa. After co-cultivation, the damage status of the algae was observed through electron microscope, and the effect of immobilized pectase on the physiological and biochemical characteristics of the algae was also measured. The results showed that the algae and immobilized pectase co-cultivated solution etiolated distinctly on the third day and there was a significantly positive correlation between the extent of etiolation and the dosage as well as the treating time of the immobilized pectinase. Under electron microscope, plasmolysis was found in the slightly damaged cells, and the cell surface of these cells was rough, uneven and irregular; the severely damaged cells were collapsed or disintegrated completely. The algal yield and the chlorophyll a content decreased significantly with the increase of the treating time. The measurement of the malondiadehyde (MDA) value showed that the antioxidation system of the treated algal cells was destroyed, and their membrane lipid was severely peroxidated. The study indicated that the immobilized pectinase could efficiently inhibit the growth of M. aeruginosa, and the inhibitory rate reached up to 96%.

Biochips: non-conventional strategies for biosensing elements immobilization.

PubMed

Marquette, Christophe A; Corgier, Benjamin P; Heyries, Kevin A; Blum, Loic J

2008-01-01

The present article draws a general picture of non-conventional methods for biomolecules immobilization. The technologies presented are based either on original solid supports or on innovative immobilization processes. Polydimethylsiloxane elastomer will be presented as a popular immobilization support within the biochip developer community. Electro-addressing of biomolecules at the surface of conducting biochips will appear to be an interesting alternative to immobilization processes based on surface functionalization. Finally, bead-assisted biomolecules immobilization will be presented as an open field of research for biochip developments.

Surface cell immobilization within perfluoroalkoxy microchannels

NASA Astrophysics Data System (ADS)

Stojkovič, Gorazd; Krivec, Matic; Vesel, Alenka; Marinšek, Marjan; Žnidaršič-Plazl, Polona

2014-11-01

Perfluoroalkoxy (PFA) is one of the most promising materials for the fabrication of cheap, solvent resistant and reusable microfluidic chips, which have been recently recognized as effective tools for biocatalytic process development. The application of biocatalysts significantly depends on efficient immobilization of enzymes or cells within the reactor enabling long-term biocatalyst use. Functionalization of PFA microchannels by 3-aminopropyltriethoxysilane (ATPES) and glutaraldehyde was used for rapid preparation of microbioreactors with surface-immobilized cells. X-ray photoelectron spectroscopy and scanning electron microscopy were used to accurately monitor individual treatment steps and to select conditions for cell immobilization. The optimized protocol for Saccharomyces cerevisiae immobilization on PFA microchannel walls comprised ethanol surface pretreatment, 4 h contacting with 10% APTES aqueous solution, 10 min treatment with 1% glutaraldehyde and 20 min contacting with cells in deionized water. The same protocol enabled also immobilization of Escherichia coli, Pseudomonas putida and Bacillus subtilis cells on PFA surface in high densities. Furthermore, the developed procedure has been proved to be very efficient also for surface immobilization of tested cells on other materials that are used for microreactor fabrication, including glass, polystyrene, poly (methyl methacrylate), polycarbonate, and two olefin-based polymers, namely Zeonor® and Topas®.

Zimbabwe's national AIDS levy: A case study.

PubMed

Bhat, Nisha; Kilmarx, Peter H; Dube, Freeman; Manenji, Albert; Dube, Medelina; Magure, Tapuwa

2016-01-01

We conducted a case study of the Zimbabwe National AIDS Trust Fund ('AIDS Levy') as an approach to domestic government financing of the response to HIV and AIDS. Data came from three sources: a literature review, including a search for grey literature, review of government documents from the Zimbabwe National AIDS Council (NAC), and key informant interviews with representatives of the Zimbabwean government, civil society and international organizations. The literature search yielded 139 sources, and 20 key informants were interviewed. Established by legislation in 1999, the AIDS Levy entails a 3% income tax for individuals and 3% tax on profits of employers and trusts (which excluded the mining industry until 2015). It is managed by the parastatal NAC through a decentralized structure of AIDS Action Committees. Revenues increased from inception to 2006 through 2008, a period of economic instability and hyperinflation. Following dollarization in 2009, annual revenues continued to increase, reaching US$38.6 million in 2014. By policy, at least 50% of funds are used for purchase of antiretroviral medications. Other spending includes administration and capital costs, HIV prevention, and monitoring and evaluation. Several financial controls and auditing systems are in place. Key informants perceived the AIDS Levy as a 'homegrown' solution that provided country ownership and reduced dependence on donor funding, but called for further increased transparency, accountability, and reduced administrative costs, as well as recommended changes to increase revenue. The Zimbabwe AIDS Levy has generated substantial resources, recently over US$35 million per year, and signals an important commitment by Zimbabweans, which may have helped attract other donor resources. Many key informants considered the Zimbabwe AIDS Levy to be a best practice for other countries to follow.

Zimbabwe's national AIDS levy: A case study

PubMed Central

Bhat, Nisha; Kilmarx, Peter H.; Dube, Freeman; Manenji, Albert; Dube, Medelina; Magure, Tapuwa

2016-01-01

Abstract Background: We conducted a case study of the Zimbabwe National AIDS Trust Fund (‘AIDS Levy’) as an approach to domestic government financing of the response to HIV and AIDS. Methods: Data came from three sources: a literature review, including a search for grey literature, review of government documents from the Zimbabwe National AIDS Council (NAC), and key informant interviews with representatives of the Zimbabwean government, civil society and international organizations. Findings: The literature search yielded 139 sources, and 20 key informants were interviewed. Established by legislation in 1999, the AIDS Levy entails a 3% income tax for individuals and 3% tax on profits of employers and trusts (which excluded the mining industry until 2015). It is managed by the parastatal NAC through a decentralized structure of AIDS Action Committees. Revenues increased from inception to 2006 through 2008, a period of economic instability and hyperinflation. Following dollarization in 2009, annual revenues continued to increase, reaching US$38.6 million in 2014. By policy, at least 50% of funds are used for purchase of antiretroviral medications. Other spending includes administration and capital costs, HIV prevention, and monitoring and evaluation. Several financial controls and auditing systems are in place. Key informants perceived the AIDS Levy as a ‘homegrown’ solution that provided country ownership and reduced dependence on donor funding, but called for further increased transparency, accountability, and reduced administrative costs, as well as recommended changes to increase revenue. Conclusions: The Zimbabwe AIDS Levy has generated substantial resources, recently over US$35 million per year, and signals an important commitment by Zimbabweans, which may have helped attract other donor resources. Many key informants considered the Zimbabwe AIDS Levy to be a best practice for other countries to follow. PMID:26781215

Effects of immobilization on articular cartilage: Autohistoradiographic findings with S35

NASA Technical Reports Server (NTRS)

Digiovanni, C.; Desantis, E.

1980-01-01

The effect of immobilization on the articular cartilage of rabbits was studied by light microscope. The knee joint of each rabbit was immobilized in a plaster in a position midway between flexion and extension for a 10 to 120 days period. Degenerative changes in the articular cartilage of increasing severity were observed. The fixation of the labeled SO4 by cartilage cells was decreased in advanced immobilization.

pH-dependent immobilization of urease on glutathione-capped gold nanoparticles.

PubMed

Garg, Seema; De, Arnab; Mozumdar, Subho

2015-05-01

Urease is a nickel-dependent metalloenzyme that catalyzes the hydrolysis of urea to form ammonia and carbon dioxide. Although the enzyme serves a significant role in several detoxification and analytical processes, its usability is restricted due to high cost, availability in small amounts, instability, and a limited possibility of economic recovery from a reaction mixture. Hence, there is a need to develop an efficient, simple, and reliable immobilization strategy for the enzyme. In this study, the carboxyl terminated surface of glutathione-capped gold nanoparticles have been utilized as a solid support for the covalent attachment of urease. The immobilization has been carried out at different pH conditions so as to elucidate its effect on the immobilization efficiency and enzyme bioactivity. The binding of the enzyme has been quantitatively and qualitatively analyzed through techniques like ultraviolet-visible spectroscopy, intrinsic steady state fluorescence, and circular dichorism. The bioactivity of the immobilized enzyme was investigated with respect to the native enzyme under different thermal conditions. Recyclability and shelf life studies of the immobilized enzyme have also been carried out. Results reveal that the immobilization is most effective at pH of 7.4 followed by that in an acidic medium and is least in alkaline environment. The immobilized enzyme also exhibits enhance activity in comparison to the native form at physiological temperature. The immobilized urease (on gold glutathione nanoconjugates surface) can be effectively employed for biosensor fabrication, immunoassays and as an in vivo diagnostic tool in the future. © 2014 Wiley Periodicals, Inc.

Determinants of burn first aid knowledge: Cross-sectional study.

PubMed

Wallace, Hilary J; O'Neill, Tomas B; Wood, Fiona M; Edgar, Dale W; Rea, Suzanne M

2013-09-01

This study investigated demographic factors, experience of burn/care and first aid course attendance as factors influencing burn first aid knowledge. A cross-sectional study was undertaken using convenience sampling of members of sporting and recreation clubs. The main outcome measure was the proportion of correct responses to multiple-choice questions relating to four burn scenarios: (1) scald, (2) contact burn, (3) ignited clothing, and (4) chemical burn. A total of 2602 responses were obtained. Large gaps (30-50% incorrect answers) were identified in burn first aid knowledge across all scenarios. 15% more individuals gave correct answers if they had attended a first aid course compared to those who had not (p<0.0001); this proportion increased if the course was undertaken within the previous five years (p<0.0001) or contained a burns-specific component (p<0.0001). Males and younger (≤25 years) and older (≥65 years) age-groups had relatively lower levels of burn first aid knowledge. Gender and age were significant predictors of first aid course attendance, with males and younger (≤25 years) and older (≥65 years) age-groups less likely to have attended a first aid course. In this sample, first aid training undertaken within the last 5 years with a specific burns component was associated with enhanced burn first aid knowledge. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

Bioreactors with immobilized lipases: state of the art.

PubMed

Balcão, V M; Paiva, A L; Malcata, F X

1996-05-01

This review attempts to provide an updated compilation of studies reported in the literature pertaining to reactors containing lipases in immobilized forms, in a way that helps the reader direct a bibliographic search and develop an integrated perspective of the subject. Highlights are given to industrial applications of lipases (including control and economic considerations), as well as to methods of immobilization and configurations of reactors in which lipases are used. Features associated with immobilized lipase kinetics such as enzyme activities, adsorption properties, optimum operating conditions, and estimates of the lumped parameters in classical kinetic formulations (Michaelis-Menten model for enzyme action and first-order model for enzyme decay) are presented in the text in a systematic tabular form.

[Interaction of immobilization stress and food-getting learning].

PubMed

Levshina, I P; Stashkevich, I S; Shuĭkin, N N

2009-01-01

The behavioral effects of emotional negative stress (immobilization) were studied in Wistar rats intact and those that had previous positive emotion experience. The food-getting learning has been chosen as positive emotion experience. Animals were trained in food pellet-reaching task by their preferred paw. It was shown that immobilization of intact rats leads to suppression of motor activity and increasing the duration of grooming. These effects indicate enhancement of passive-avoidance reactions. It was also shown that motor learning in group of rats with food reinforcement before immobilisation significantly reduces appearance of passive-avoidance reactions. It was found that immobilization stress does not inverse the initial direction of limb preference in majority of rats.

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…

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.

Nanoporous Gold for Enzyme Immobilization.

PubMed

Stine, Keith J; Jefferson, Kenise; Shulga, Olga V

2017-01-01

Nanoporous gold (NPG) is a material of emerging interest for immobilization of biomolecules, especially enzymes. The material provides a high surface area form of gold that is suitable for physisorption or for covalent modification by self-assembled monolayers. The material can be used as a high surface area electrode and with immobilized enzymes can be used for amperometric detection schemes. NPG can be prepared in a variety of formats from alloys containing between 20 and 50 % atomic composition of gold and less noble element(s) by dealloying procedures. Materials resembling NPG can be prepared by hydrothermal and electrodeposition methods. Related high surface area gold structures have been prepared using templating approaches. Covalent enzyme immobilization can be achieved by first forming a self-assembled monolayer on NPG bearing a terminal reactive functional group followed by conjugation to the enzyme through amide linkages to lysine residues. Enzymes can also be entrapped by physisorption or immobilized by electrostatic interactions.

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.

An orientation analysis method for protein immobilized on quantum dot particles

NASA Astrophysics Data System (ADS)

Aoyagi, Satoka; Inoue, Masae

2009-11-01

The evaluation of orientation of biomolecules immobilized on nanodevices is crucial for the development of high performance devices. Such analysis requires ultra high sensitivity so as to be able to detect less than one molecular layer on a device. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) has sufficient sensitivity to evaluate the uppermost surface structure of a single molecular layer. The objective of this study is to develop an orientation analysis method for proteins immobilized on nanomaterials such as quantum dot particles, and to evaluate the orientation of streptavidin immobilized on quantum dot particles by means of TOF-SIMS. In order to detect fragment ions specific to the protein surface, a monoatomic primary ion source (Ga +) and a cluster ion source (Au 3+) were employed. Streptavidin-immobilized quantum dot particles were immobilized on aminosilanized ITO glass plates at amino groups by covalent bonding. The reference samples streptavidin directly immobilized on ITO plates were also prepared. All samples were dried with a freeze dryer before TOF-SIMS measurement. The positive secondary ion spectra of each sample were obtained using TOF-SIMS with Ga + and Au 3+, respectively, and then they were compared so as to characterize each sample and detect the surface structure of the streptavidin immobilized with the biotin-immobilized quantum dots. The chemical structures of the upper surface of the streptavidin molecules immobilized on the quantum dot particles were evaluated with TOF-SIMS spectra analysis. The indicated surface side of the streptavidin molecules immobilized on the quantum dots includes the biotin binding site.

[Applied study of the submerged macrophytes bed-immobilized bacteria in drinking water restoration].

PubMed

Chen, Qi-Chun; Li, Zheng-Kui; Wang, Yi-Chao; Wu, Kai; Fan, Nian-Wen

2012-01-01

The effect of submerged macrophytes bed-immobilized bacteria technology which applied in drinking water restoration was studied. Ammonifying bacteria, nitrobacteria, nitrosobacteria and denitrifying bacteria which isolated from Taihu Labe was immobilized to the porous carries, combined with the submerged macrophytes bed technology, we applied the new equipment in water restoration of gonghu bay, this equipment has good ability to resist storm, the denitrifying bacteria number increased from 5.4 x 10(2)-2.7 x 10(3) to 3.9 x 10(5)-9.1 x 10(5), N2O flux of experimental plot was 3-24 microg x (m2 x h)(-1), it's more than the contrast group obviously, TN concentration reduced 19% - 74%, while NO3- concentration reduced 24% -81% after the equipment running a period of time; The experimental data of 120 days showed that this technology is suitable for drinking water restoration, as it can control eutrophication.

Evaluation of agrowastes as immobilizers for probiotics in soy milk.

PubMed

Teh, Sue-Siang; Ahmad, Rosma; Wan-Abdullah, Wan-Nadiah; Liong, Min-Tze

2009-11-11

The objective of this study was to evaluate agricultural wastes as immobilizers for probiotics in liquid foods, such as soy milk. Probiotic strains were initially evaluated for acid and bile tolerance and the ability to produce alpha-galactosidase. Rinds of durian, mangosteen, and jackfruit were dried, ground, and sterilized prior to immobilization of selected strains ( Lactobacillus acidophilus FTDC 1331, L. acidophilus FTDC 2631, L. acidophilus FTDC 2333, L. acidophilus FTDC 1733, and Lactobacillus bulgaricus FTCC 0411). Immobilized cells were inoculated into soy milk, and growth properties were evaluated over 168 h at 37 degrees C. Soy milk containing free cells without agrowastes was used as the control. Immobilized probiotics showed increased growth, greater reduction of stachyose, sucrose, and glucose, higher production of lactic and acetic acids, and lower pH in soy milk compared to the control. The results illustrated that agrowastes could be used for the immobilization of probiotics with enhanced growth, utilization of substrates, and production of organic acids.

Antimicrobial activity of immobilized lactoferrin and lactoferricin.

PubMed

Chen, Renxun; Cole, Nerida; Dutta, Debarun; Kumar, Naresh; Willcox, Mark D P

2017-11-01

Lactoferrin and lactoferricin were immobilized on glass surfaces via two linkers, 4-azidobenzoic acid (ABA) or 4-fluoro-3-nitrophenyl azide (FNA). The resulting surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The antimicrobial activity of the surfaces was determined using Pseudomonas aeruginosa and Staphylococcus aureus strains by fluorescence microscopy. Lactoferrin and lactoferricin immobilization was confirmed by XPS showing significant increases (p < 0.05) in nitrogen on the glass surface. The immobilization of both proteins slightly increased the overall hydrophobicity of the glass. Both lactoferrin and lactoferricin immobilized on glass significantly (p < 0.05) reduced the numbers of viable bacterial cells adherent to the glass. For P. aeruginosa, the immobilized proteins consistently increased the percentage of dead cells compared to the total cells adherent to the glass surfaces (p < 0.03). Lactoferrin and lactoferricin were successfully immobilized on glass surfaces and showed promising antimicrobial activity against pathogenic bacteria. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2612-2617, 2017. © 2016 Wiley Periodicals, Inc.

[Immobilization of Candida sp. lipase on resin D301].

PubMed

Wang, Yanhua; Zhu, Kai; Liu, Hui; Han, Pingfang; Wei, Ping

2009-12-01

We immobilized Candida sp. lipase onto seven kinds of industrial adsorption and ion exchange resins. By determining the activity of each immobilized enzyme, the weakly basic anionic exchange resin of D301 showed the best results for the immobilization of Candida sp. lipase. Comparing the scanning electron micrographs of D301 with Novozym 435 (immobilized Candida antarctica lipase B from Novo Nordisk Corp.), we selected D301 as a carrier for the immobilization of Candida sp. lipase. And we pretreated the resin D301 with the bifunctional agent glutaraldehyde and crosslinked it with Candida sp. lipase. The optimal conditions for the immobilization of Candida sp. lipase were as follows: 8 mL of the amount of 5% glutaraldehyde solution, five hours of the time pretreated D301 with glutaraldehyde, 1.0 g/L the concentration of Candida sp. lipase used, pH of the phosphate buffered, 6.0 and 10 hours of time for immobilization, respectively. The activity of immobilized enzyme was over 35 U/mg and the efficiency of immobilization was around 3.5 Ul(mg x h).

Solution-derived sodalite made with Si- and Ge-ethoxide precursors for immobilizing electrorefiner salt

NASA Astrophysics Data System (ADS)

Riley, Brian J.; Lepry, William C.; Crum, Jarrod V.

2016-01-01

Chlorosodalite has the general form of Na8(AlSiO4)6Cl2 and this paper describes experiments conducted to synthesize sodalite with a solution-based approach to immobilize a simulated spent electrorefiner salt solution containing a mixture of alkali, alkaline earth, and lanthanide chlorides. The reactants used were the salt solution, NaAlO2, and either Si(OC2H5)4 or Ge(OC2H5)4. Additionally, seven different glass sintering aids (at loadings of 5 mass%) were evaluated as sintering aids for consolidating the as-made powders using a cold-press-and-sinter technique. This process of using alkoxide additives for the Group IV component can be used to produce large quantities of sodalite at near-room temperature as compared to a method where colloidal silica was used as the silica source. However, the small particle sizes inhibited densification during heat treatments.

Enhanced stability of catalase covalently immobilized on functionalized titania submicrospheres.

PubMed

Wu, Hong; Liang, Yanpeng; Shi, Jiafu; Wang, Xiaoli; Yang, Dong; Jiang, Zhongyi

2013-04-01

In this study, a novel approach combing the chelation and covalent binding was explored for facile and efficient enzyme immobilization. The unique capability of titania to chelate with catecholic derivatives at ambient conditions was utilized for titania surface functionalization. The functionalized titania was then used for enzyme immobilization. Titania submicrospheres (500-600 nm) were synthesized by a modified sol-gel method and functionalized with carboxylic acid groups through a facile chelation method by using 3-(3,4-dihydroxyphenyl) propionic acid as the chelating agent. Then, catalase (CAT) was covalently immobilized on these functionalized titania submicrospheres through 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) coupling reaction. The immobilized CAT retained 65% of its free form activity with a loading capacity of 100-150 mg/g titania. The pH stability, thermostability, recycling stability and storage stability of the immobilized CAT were evaluated. A remarkable enhancement in enzyme stability was achieved. The immobilized CAT retained 90% and 76% of its initial activity after 10 and 16 successive cycles of decomposition of hydrogen peroxide, respectively. Both the Km and the Vmax values of the immobilized CAT (27.4 mM, 13.36 mM/min) were close to those of the free CAT (25.7 mM, 13.46 mM/min). Copyright © 2012 Elsevier B.V. All rights reserved.

[Study on influence between activated carbon property and immobilized biological activated carbon purification effect].

PubMed

Wang, Guang-zhi; Li, Wei-guang; He, Wen-jie; Han, Hong-da; Ding, Chi; Ma, Xiao-na; Qu, Yan-ming

2006-10-01

By means of immobilizing five kinds of activated carbon, we studied the influence between the chief activated carbon property items and immobilized bioactivated carbon (IBAC) purification effect with the correlation analysis. The result shows that the activated carbon property items which the correlation coefficient is up 0.7 include molasses, abrasion number, hardness, tannin, uniform coefficient, mean particle diameter and effective particle diameter; the activated carbon property items which the correlation coefficient is up 0.5 include pH, iodine, butane and tetrachloride. In succession, the partial correlation analysis shows that activated carbon property items mostly influencing on IBAC purification effect include molasses, hardness, abrasion number, uniform coefficient, mean particle diameter and effective particle diameter. The causation of these property items bringing influence on IBAC purification is that the activated carbon holes distribution (representative activated carbon property item is molasses) provides inhabitable location and adjust food for the dominance bacteria; the mechanical resist-crash property of activated carbon (representative activated carbon property items: abrasion number and hardness) have influence on the stability of biofilm; and the particle diameter size and distribution of activated carbon (representative activated carbon property items: uniform coefficient, mean particle diameter and effective particle diameter) can directly affect the force of water in IBAC filter bed, which brings influence on the dominance bacteria immobilizing on activated carbon.

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.

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.

Simultaneous immobilization of metals and arsenic in acidic polluted soils near a copper smelter in central Chile.

PubMed

Cárcamo, Valeska; Bustamante, Elena; Trangolao, Elizabeth; de la Fuente, Luz María; Mench, Michel; Neaman, Alexander; Ginocchio, Rosanna

2012-05-01

Acidic and metal(oid)-rich topsoils resulted after 34 years of continuous operations of a copper smelter in the Puchuncaví valley, central Chile. Currently, large-scale remediation actions for simultaneous in situ immobilization of metals and As are needed to reduce environmental risks of polluted soils. Aided phytostabilization is a cost-effective alternative, but adequate local available soil amendments have to be identified and management options have to be defined. Efficacy of seashell grit (SG), biosolids (B), natural zeolite (Z), and iron-activated zeolite (AZ), either alone or in mixtures, was evaluated for reducing metal (Cu and Zn) and As solubilization in polluted soils under laboratory conditions. Perennial ryegrass was used to test phytotoxicity of experimental substrates. Soil neutralization to a pH of 6.5 with SG, with or without incorporation of AZ, significantly reduces metal (Cu and Zn) solubilization without affecting As solubilization in soil pore water; furthermore, it eliminates phytotoxicity and excessive metal(oid) accumulation in aerial plant tissues. Addition of B or Z to SG-amended soil does not further reduce metal solubilization into soil pore water, but increase As solubilization due to excessive soil neutralization (pH > 6.5); however, no significant As increase occurs in aerial plant tissues. Simultaneous in situ immobilization of metal(oid) in acidic topsoils is possible through aided phytostabilization.

Health-care workers are losing most AIDS lawsuits, study says.

PubMed

1996-08-09

The Kaiser Family Foundation funded a Georgetown study, The AIDS Litigation Project III--A Look at AIDS in the Courts in the 1990s, to analyze AIDS-related cases in the Federal and State court systems since January 1991. Study director Lawrence Gostin concludes that AIDS has become the most litigated disease in U.S. history and that judges tend to side with the argument that disability rights laws must yield to concern about the possible transmission risks. Initially, courts were supportive of the rights of persons living with AIDS. Currently, courts are likely to support mandatory HIV-antibody testing of health-care employees, prison inmates, and criminal defendants. Gostin predicts that court cases will focus on the rights of patients to receive health insurance coverage for AIDS therapies. Other emerging trends in AIDS litigation are cases involving HIV status disclosure and sexual ethics.

Immobilization of Pseudomonas sp. DG17 onto sodium alginate–attapulgite–calcium carbonate

PubMed Central

Wang, Hong Qi; Hua, Fei; Zhao, Yi Cun; Li, Yi; Wang, Xuan

2014-01-01

A strain of Pseudomonas sp. DG17, capable of degrading crude oil, was immobilized in sodium alginate–attapulgite–calcium carbonate for biodegradation of crude oil contaminated soil. In this work, proportion of independent variables, the laboratory immobilization parameters, the micromorphology and internal structure of the immobilized granule, as well as the crude oil biodegradation by sodium alginate–attapulgite–calcium carbonate immobilized cells and sodium alginate–attapulgite immobilized cells were studied to build the optimal immobilization carrier and granule-forming method. The results showed that the optimal concentrations of sodium alginate–attapulgite–calcium carbonate and calcium chloride were 2.5%–3.5%, 0.5%–1%, 3%–7% and 2%–4%, respectively. Meanwhile, the optimal bath temperature, embedding cell amount, reaction time and multiplication time were 50–60 °C, 2%, 18 h and 48 h, respectively. Moreover, biodegradation was enhanced by immobilized cells with a total petroleum hydrocarbon removal ranging from 33.56% ± 3.84% to 56.82% ± 3.26% after 20 days. The SEM results indicated that adding calcium carbonate was helpful to form internal honeycomb-like pores in the immobilized granules. PMID:26019567

Turkish Version of Kolcaba's Immobilization Comfort Questionnaire: A Validity and Reliability Study.

PubMed

Tosun, Betül; Aslan, Özlem; Tunay, Servet; Akyüz, Aygül; Özkan, Hüseyin; Bek, Doğan; Açıksöz, Semra

2015-12-01

The purpose of this study was to determine the validity and reliability of the Turkish version of the Immobilization Comfort Questionnaire (ICQ). The sample used in this methodological study consisted of 121 patients undergoing lower extremity arthroscopy in a training and research hospital. The validity study of the questionnaire assessed language validity, structural validity and criterion validity. Structural validity was evaluated via exploratory factor analysis. Criterion validity was evaluated by assessing the correlation between the visual analog scale (VAS) scores (i.e., the comfort and pain VAS scores) and the ICQ scores using Spearman's correlation test. The Kaiser-Meyer-Olkin coefficient and Bartlett's test of sphericity were used to determine the suitability of the data for factor analysis. Internal consistency was evaluated to determine reliability. The data were analyzed with SPSS version 15.00 for Windows. Descriptive statistics were presented as frequencies, percentages, means and standard deviations. A p value ≤ .05 was considered statistically significant. A moderate positive correlation was found between the ICQ scores and the VAS comfort scores; a moderate negative correlation was found between the ICQ and the VAS pain measures in the criterion validity analysis. Cronbach α values of .75 and .82 were found for the first and second measurements, respectively. The findings of this study reveal that the ICQ is a valid and reliable tool for assessing the comfort of patients in Turkey who are immobilized because of lower extremity orthopedic problems. Copyright © 2015. Published by Elsevier B.V.

Anti-fouling properties of Fab' fragments immobilized on silane-based adlayers

NASA Astrophysics Data System (ADS)

Crivianu-Gaita, Victor; Romaschin, Alexander; Thompson, Michael

2015-12-01

Biosensors require surfaces that are highly specific towards the target analyte and that are minimally fouling. However, surface tuning to minimize fouling is a difficult task. The last decade has seen an increase in the use of immobilized antigen-binding antibody fragments (Fab') in biosensors. One Fab' linker compound S-(11-trichlorosilyl-undecanyl)-benzothiosulfonate (TUBTS) and three spacers were used to create the silane-based adlayers. The ultra-high frequency electromagnetic piezoelectric acoustic sensor (EMPAS) was used to gauge the fouling properties of the various surfaces using bovine serum albumin (BSA), goat IgG, and mouse serum. X-ray photoelectron spectroscopy (XPS), contact angle, and atomic force microscopy (AFM) were employed to characterize the surfaces. It was discovered that immobilized oriented Fab' fragments reduced the fouling levels of surfaces up to 80% compared to the surfaces without fragments. An explanation for this phenomenon is that the antibody fragments increase the hydration of the surfaces and aid in the formation of an anti-fouling water barrier. The anti-fouling effect of the Fab' fragments is at its maximum when there is an even distribution of fragments across the surfaces. Finally, using Fab'-covered surfaces, a cancer biomarker was detected from serum, showing the applicability of this work to the field of biodetection.

Bioremediation of contaminated surface water by immobilized Micrococcus roseus.

PubMed

Li, H; Li, P; Hua, T; Zhang, Y; Xiong, X; Gong, Z

2005-08-01

The problems caused by contaminated surface water have gradually become more serious in recent years. Although various remediation technologies were investigated, unfortunately, no efficient method was developed. In this paper, a new bioremediation technology was studied using Micrococcus roseus, which was immobilized in porous spherical beads by an improved polyvinyl alcohol (PVA) - sodium alginate (SA) embedding method. The experimental results indicated that COD removal rate could reach 64.7 % within 72 hours when immobilized M. roseus beads were used, which was ten times as high as that of free cells. The optimum inoculation rate of immobilized M. roseus beads was 10 % (mass percent of the beads in water sample, g g(-1)). Suitable aeration was proved necessary to enhance the bioremediation process. The immobilized cells had an excellent tolerance to pH and temperature changes, and were also more resistant to heavy metal stress compared with free cells. The immobilized M. roseus beads had an excellent regeneration capacity and could be reused after 180-day continuous usage. The Scanning Electronic Microscope (SEM) analysis showed that the bead microstructure was suitable for M. roseus growth, however, some defect structures should still be improved.

Study on the biodegradation of crude oil by free and immobilized bacterial consortium in marine environment.

PubMed

Chen, Qingguo; Li, Jingjing; Liu, Mei; Sun, Huiling; Bao, Mutai

2017-01-01

Five strains of bacteria, namely, Exiguobacterium sp. ASW-1, Pseudomonas aeruginosa strain ASW-2, Alcaligenes sp. ASW-3, Alcaligenes sp. ASS-1, and Bacillus sp. ASS-2, were isolated from the Zhejiang coast in China. The mixed flora of the five strains performed well with degrading 75.1% crude oil (1%, w/v) in 7 days. The calcium alginate-activated carbon embedding carrier was used to immobilize bacterial consortium. Immobilized cells performed better than free ones in variations of environmental factors containing incubated temperature, initial pH, salinity of the medium and crude oil concentration. The degradation process of crude oil by immobilized bacteria was accelerated compared with that of the free ones. Bacterial consortium showed better performance on biodegradation of normal alkanes than that of PAHs. Improvement of immobilization on the biodegradation efficiency of normal alkanes (31.9%) was apparently high than that of PAHs (1.9%).

Study on the biodegradation of crude oil by free and immobilized bacterial consortium in marine environment

PubMed Central

Li, Jingjing; Liu, Mei; Sun, Huiling; Bao, Mutai

2017-01-01

Five strains of bacteria, namely, Exiguobacterium sp. ASW-1, Pseudomonas aeruginosa strain ASW-2, Alcaligenes sp. ASW-3, Alcaligenes sp. ASS-1, and Bacillus sp. ASS-2, were isolated from the Zhejiang coast in China. The mixed flora of the five strains performed well with degrading 75.1% crude oil (1%, w/v) in 7 days. The calcium alginate—activated carbon embedding carrier was used to immobilize bacterial consortium. Immobilized cells performed better than free ones in variations of environmental factors containing incubated temperature, initial pH, salinity of the medium and crude oil concentration. The degradation process of crude oil by immobilized bacteria was accelerated compared with that of the free ones. Bacterial consortium showed better performance on biodegradation of normal alkanes than that of PAHs. Improvement of immobilization on the biodegradation efficiency of normal alkanes (31.9%) was apparently high than that of PAHs (1.9%). PMID:28346510

Optimization of Enzyme Co-Immobilization with Sodium Alginate and Glutaraldehyde-Activated Chitosan Beads.

PubMed

Gür, Sinem Diken; İdil, Neslihan; Aksöz, Nilüfer

2018-02-01

In this study, two different materials-alginate and glutaraldehyde-activated chitosan beads-were used for the co-immobilization of α-amylase, protease, and pectinase. Firstly, optimization of multienzyme immobilization with Na alginate beads was carried out. Optimum Na alginate and CaCl 2 concentration were found to be 2.5% and 0.1 M, respectively, and optimal enzyme loading ratio was determined as 2:1:0.02 for pectinase, protease, and α-amylase, respectively. Next, the immobilization of multiple enzymes on glutaraldehyde-activated chitosan beads was optimized (3% chitosan concentration, 0.25% glutaraldehyde with 3 h of activation and 3 h of coupling time). While co-immobilization was successfully performed with both materials, the specific activities of enzymes were found to be higher for the enzymes co-immobilized with glutaraldehyde-activated chitosan beads. In this process, glutaraldehyde was acting as a spacer arm. SEM and FTIR were used for the characterization of activated chitosan beads. Moreover, pectinase and α-amylase enzymes immobilized with chitosan beads were also found to have higher activity than their free forms. Three different enzymes were co-immobilized with these two materials for the first time in this study.

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.

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.

Immobilization of pectinase onto chitosan magnetic nanoparticles by macromolecular cross-linker.

PubMed

Sojitra, Uttam V; Nadar, Shamraja S; Rathod, Virendra K

2017-02-10

Pectinase was immobilized onto chitosan magnetic nanoparticles (CMNPs) by dextran polyaldehyde as a macromolecular cross-linking agent. The parameters like cross-linking concentration, time and CMNPs to enzyme ratio were optimized. Further, prepared magnetic pectinase nanobiocatalyst was characterized by FT-IR and XRD. The thermal kinetic studies for immobilized pectinase showed two folds improved thermal stability in the range of 55-75°C as compared to free form. The V max and K m values of immobilized pectinase were found to be nearly equal to native form which indicated that conformational flexibility of pectinase was retained even after immobilization. The residual activity of immobilized pectinase was 85% after seven successive cycles of reuse, while it retained upto 89% residual activity on storage of fifteen days which exhibited excellent stability and durability. The conformational changes in pectinase after immobilization were evaluated by FT-IR spectroscopy data analysis tools. Finally, magnetic pectinase nanobiocatalyst was employed for apple juice clarification which showed turbidity reduction upto 74% after 150min treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Study on immobilization of yeast alcohol dehydrogenase on nanocrystalline Ni-Co ferrites as magnetic support.

PubMed

Shakir, Mohammad; Nasir, Zeba; Khan, Mohd Shoeb; Lutfullah; Alam, Md Fazle; Younus, Hina; Al-Resayes, Saud Ibrahim

2015-01-01

The covalent binding of yeast alcohol dehydrogenase (YADH) enzyme complex in a series of magnetic crystalline Ni-Co nanoferrites, synthesized via sol-gel auto combustion technique was investigated. The structural analysis, morphology and magnetic properties of Ni-Co nanoferrites were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), vibrating-sample magnetometer (VSM), high resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR). The comparative analysis of the HRTEM micrographs of bare magnetic nanoferrite particles and particles immobilized with enzyme revealed an uniform distribution of the particles in both the cases without undergoing change in the size which was found to be in the range 20-30 nm. The binding of YADH to Ni-Co nanoferrites and the possible binding mechanism have been suggested by comparing the FTIR results. The binding properties of the immobilized YADH enzyme were also studied by kinetic parameters, optimum operational pH, temperature, thermal stability and reusability. The immobilized YADH exhibits enhanced thermal stability as compared to the free enzyme over a wide range of temperature and pH, and showed good durability after recovery by magnetic separation for repeated use. Copyright © 2014 Elsevier B.V. All rights reserved.

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.

Novel immobilization process of a thermophilic catalase: efficient purification by heat treatment and subsequent immobilization at high temperature.

PubMed

Xu, Juan; Luo, Hui; López, Claudia; Xiao, Jing; Chang, Yanhong

2015-10-01

The main goal of the present work is to investigate a novel process of purification and immobilization of a thermophilic catalase at high temperatures. The catalase, originated from Bacillus sp., was overexpressed in a recombinant Escherichia coli BL21(DE3)/pET28-CATHis and efficiently purified by heat treatment, achieving a threefold purification. The purified catalase was then immobilized onto an epoxy support at different temperatures (25, 40, and 55 °C). The immobilizate obtained at higher temperatures reached its maximum activity in a shorter time than that obtained at lower temperatures. Furthermore, immobilization at higher temperatures required a lower ionic strength than immobilization at lower temperatures. The characteristics of immobilized enzymes prepared at different temperatures were investigated. The high-temperature immobilizate (55 °C) showed the highest thermal stability, followed by the 40 °C immobilizate. And the high-temperature immobilizate (55 °C) had slightly higher operational stability than the 25 °C immobilizate. All of the immobilized catalase preparations showed higher stability than the free enzyme at alkaline pH 10.0, while the alkali resistance of the 25 °C immobilizate was slightly better than that of the 40 and 55 °C immobilizates.

Cortical Reorganization after Hand Immobilization: The beta qEEG Spectral Coherence Evidences

PubMed Central

Fortuna, Marina; Teixeira, Silmar; Machado, Sérgio; Velasques, Bruna; Bittencourt, Juliana; Peressutti, Caroline; Budde, Henning; Cagy, Mauricio; Nardi, Antonio E.; Piedade, Roberto; Ribeiro, Pedro; Arias-Carrión, Oscar

2013-01-01

There is increasing evidence that hand immobilization is associated with various changes in the brain. Indeed, beta band coherence is strongly related to motor act and sensitive stimuli. In this study we investigate the electrophysiological and cortical changes that occur when subjects are submitted to hand immobilization. We hypothesized that beta coherence oscillations act as a mechanism underlying inter- and intra-hemispheric changes. As a methodology for our study fifteen healthy individuals between the ages of 20 and 30 years were subjected to a right index finger task before and after hand immobilization while their brain activity pattern was recorded using quantitative electroencephalography. This analysis revealed that hand immobilization caused changes in frontal, central and parietal areas of the brain. The main findings showed a lower beta-2 band in frontal regions and greater cortical activity in central and parietal areas. In summary, the coherence increased in the frontal, central and parietal cortex, due to hand immobilization and it adjusted the brains functioning, which had been disrupted by the procedure. Moreover, the brain adaptation upon hand immobilization of the subjects involved inter- and intra-hemispheric changes. PMID:24278213

Pineapple stem bromelain immobilized on different supports: catalytic properties in model wine.

PubMed

Ilaria, Benucci; Marco, Esti; Katia, Liburdi; Maria Vittoria, Garzillo Anna

2012-01-01

Bromelain from pineapple stem has been covalently immobilized on different supports to select the more efficient biocatalyst that should be applied toward unstable proteins in real white wine. In this preliminary study, catalytic properties of different immobilized bromelain forms were compared under wine-like conditions, against a synthetic substrate (Bz-Phe-Val-Arg-pNA).Covalent immobilization affected protease kinetic properties, even if all immobilized forms presented both a better substrate affinity and higher half-life (with the exception of a few procedures) with respect to the free enzyme. Stem bromelain was successfully immobilized on chitosan beads without glutaraldehyde thus yielding a food-safe and promising biocatalyst for unstable real wine future application. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

A comparison of the techniques of PIXE, PIGE and INAA by reference to the elemental analysis of porcine brain samples

NASA Astrophysics Data System (ADS)

Stedman, J. D.; Spyrou, N. M.

1994-12-01

The trace element concentrations in porcine brain samples as determined by particle-induced X-ray emission (PIXE) analysis, instrumental neutron activation analysis (INAA) and particle-induced gamma-ray emission (PIGE) analysis are compared. The matrix composition was determined by Rutherford backscattering (RBS). Al, Si, P, S, Cl, K, Ca, Mn, Fe and Cd were determined by PIXE analysis Na, K, Sc, Fe, Co, Zn, As, Br, Rb, and Cs by INAA and Na, Mg and Fe by PIGE analysis. The bulk elements C, N, O, Na Cl and S were found by RBS analysis. Elemental concentrations are obtained using the comparator method of analysis rather than an absolute method, the validity which is examined by comparing the elemental concentrations obtained in porcine brain using two separate certified reference materials.

Optimizing immobilized enzyme performance in cell-free environments to produce liquid fuels.

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

Kumar, Sanat

The overall goal of this project was to optimize enzyme performance for the production of bio-diesel fuel. Enzyme immobilization has attracted much attention as a means to increase productivity. Mesorporous silica materials have been known to be best suited for immobilizing enzymes. A major challenge is to ensure that the enzymatic activity is retained after immobilization. Two major factors which drive enzymatic deactivation are protein-surface and inter-protein interactions. Previously, we studied protein stability inside pores and how to optimize protein-surface interactions to minimize protein denaturation. In this work we studied eh effect of surface curvature and chemistry on inter-protein interactions.more » Our goal was to find suitable immobilization supports which minimize these inter-protein interactions. Our studies carried out in the frame work of Hydrophobic-Polar (HP) model showed that enzymes immobilized inside hydrophobic pores of optimal sizes are best suited to minimize these inter-protein interactions. Besides, this study is also of biological importance to understand the role of chaperonins in protein disaggregation. Both of these aspects profited immensely with collaborations with our experimental colleague, Prof. Georges Belfort (RPI), who performed the experimental analog of our theoretical works.« less

Degradation of Carbazole by Microbial Cells Immobilized in Magnetic Gellan Gum Gel Beads▿

PubMed Central

Wang, Xia; Gai, Zhonghui; Yu, Bo; Feng, Jinhui; Xu, Changyong; Yuan, Yong; Lin, Zhixin; Xu, Ping

2007-01-01

Polycyclic aromatic heterocycles, such as carbazole, are environmental contaminants suspected of posing human health risks. In this study, we investigated the degradation of carbazole by immobilized Sphingomonas sp. strain XLDN2-5 cells. Four kinds of polymers were evaluated as immobilization supports for Sphingomonas sp. strain XLDN2-5. After comparison with agar, alginate, and κ-carrageenan, gellan gum was selected as the optimal immobilization support. Furthermore, Fe3O4 nanoparticles were prepared by a coprecipitation method, and the average particle size was about 20 nm with 49.65-electromagnetic-unit (emu) g−1 saturation magnetization. When the mixture of gellan gel and the Fe3O4 nanoparticles served as an immobilization support, the magnetically immobilized cells were prepared by an ionotropic method. The biodegradation experiments were carried out by employing free cells, nonmagnetically immobilized cells, and magnetically immobilized cells in aqueous phase. The results showed that the magnetically immobilized cells presented higher carbazole biodegradation activity than nonmagnetically immobilized cells and free cells. The highest biodegradation activity was obtained when the concentration of Fe3O4 nanoparticles was 9 mg ml−1 and the saturation magnetization of magnetically immobilized cells was 11.08 emu g−1. Additionally, the recycling experiments demonstrated that the degradation activity of magnetically immobilized cells increased gradually during the eight recycles. These results support developing efficient biocatalysts using magnetically immobilized cells and provide a promising technique for improving biocatalysts used in the biodegradation of not only carbazole, but also other hazardous organic compounds. PMID:17827304

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.

Effect of sulfonylureas administered centrally on the blood glucose level in immobilization stress model.

PubMed

Sharma, Naveen; Sim, Yun-Beom; Park, Soo-Hyun; Lim, Su-Min; Kim, Sung-Su; Jung, Jun-Sub; Hong, Jae-Seung; Suh, Hong-Won

2015-05-01

Sulfonylureas are widely used as an antidiabetic drug. In the present study, the effects of sulfonylurea administered supraspinally on immobilization stress-induced blood glucose level were studied in ICR mice. Mice were once enforced into immobilization stress for 30 min and returned to the cage. The blood glucose level was measured 30, 60, and 120 min after immobilization stress initiation. We found that intracerebroventricular (i.c.v.) injection with 30 µg of glyburide, glipizide, glimepiride or tolazamide attenuated the increased blood glucose level induced by immobilization stress. Immobilization stress causes an elevation of the blood corticosterone and insulin levels. Sulfonylureas pretreated i.c.v. caused a further elevation of the blood corticosterone level when mice were forced into the stress. In addition, sulfonylureas pretreated i.c.v. alone caused an elevation of the plasma insulin level. Furthermore, immobilization stress-induced insulin level was reduced by i.c.v. pretreated sulfonylureas. Our results suggest that lowering effect of sulfonylureas administered supraspinally against immobilization stress-induced increase of the blood glucose level appears to be primarily mediated via elevation of the plasma insulin level.

Immobilization of microorganisms for detection by solid-phase immunoassays.

PubMed Central

Ibrahim, G F; Lyons, M J; Walker, R A; Fleet, G H

1985-01-01

Several cultures of gram-negative and gram-positive bacteria were successfully immobilized with titanous hydroxide. The immobilization efficiency for the microorganisms investigated in saline and broth media ranged from 80.2 to 99.9%. The immobilization of salmonellae was effective over a wide pH range. The presence of buffers, particularly phosphate buffer, drastically reduced the immobilization rate. However, buffers may be added to immunoassay systems after immobilization of microorganisms. The immobilization process involved only one step, i.e., shaking 100 microliter of culture with 50 microliter of titanous hydroxide suspension in polystyrene tubes for only 10 min. The immobilized cells were so tenaciously bound that vigorous agitation for 24 h did not result in cell dissociation. The nonspecific binding of 125I-labeled antibody from rabbits and 125I-labeled protein A by titanous hydroxide was inhibited in the presence of 2% gelatin and amounted to only 5.6 and 3.9%, respectively. We conclude that this immobilization procedure is a potentially powerful tool which could be utilized in solid-phase immunoassays concerned with the diagnosis of microorganisms. PMID:3900128

Radiofrequency treatment enhances the catalytic function of an immobilized nanobiohybrid catalyst

NASA Astrophysics Data System (ADS)

San, Boi Hoa; Ha, Eun-Ju; Paik, Hyun-Jong; Kim, Kyeong Kyu

2014-05-01

Biocatalysis, the use of enzymes in chemical transformation, has undergone intensive development for a wide range of applications. As such, maximizing the functionality of enzymes for biocatalysis is a major priority to enable industrial use. To date, many innovative technologies have been developed to address the future demand of enzymes for these purposes, but maximizing the catalytic activity of enzymes remains a challenge. In this study, we demonstrated that the functionality of a nanobiocatalyst could be enhanced by combining immobilization and radiofrequency (RF) treatment. Aminopeptidase PepA-encapsulating 2 nm platinum nanoparticles (PepA-PtNPs) with the catalytic activities of hydrolysis and hydrogenation were employed as multifunctional nanobiocatalysts. Immobilizing the nanobiocatalysts in a hydrogel using metal chelation significantly enhanced their functionalities, including catalytic power, thermal-stability, pH tolerance, organic solvent tolerance, and reusability. Most importantly, RF treatment of the hydrogel-immobilized PepA-PtNPs increased their catalytic power by 2.5 fold greater than the immobilized PepA. Our findings indicate that the catalytic activities and functionalities of PepA-PtNPs are greatly enhanced by the combination of hydrogel-immobilization and RF treatment. Based on our findings, we propose that RF treatment of nanobiohybrid catalysts immobilized on the bulk hydrogel represents a new strategy for achieving efficient biocatalysis.Biocatalysis, the use of enzymes in chemical transformation, has undergone intensive development for a wide range of applications. As such, maximizing the functionality of enzymes for biocatalysis is a major priority to enable industrial use. To date, many innovative technologies have been developed to address the future demand of enzymes for these purposes, but maximizing the catalytic activity of enzymes remains a challenge. In this study, we demonstrated that the functionality of a nanobiocatalyst

Effects of two educational method of lecturing and role playing on knowledge and performance of high school students in first aid at emergency scene.

PubMed

Hassanzadeh, Akbar; Vasili, Arezu; Zare, Zahra

2010-01-01

This study aimed to investigate the effects of two educational methods on students' knowledge and performance regarding first aid at emergency scenes. In this semi-experimental study, the sample was selected randomly among male and female public high school students of Isfahan. Each group included 60 students. At first the knowledge and performance of students in first aid at emergency scene was assessed using a researcher-made questionnaire. Then necessary education was provided to the students within 10 sessions of two hours by lecturing and role playing. The students' knowledge and performance was as-sessed again and the results were compared. It was no significant relationship between the frequency distribution of students' age, major and knowledge and performance before the educational course in the two groups. The score of knowledge in performing CPR, using proper way to bandage, immobilizing the injured area, and proper ways of carrying injured person after the education was significantly increased in both groups. Moreover, the performance in proper way to bandage, immobilizing injured area and proper ways of carrying injured person after educational course was significantly higher in playing role group compared to lecturing group after education. Iran is a developing country with a young generation and it is a country with high risk of natural disasters; so, providing necessary education with more effective methods can be effective in reducing mortality and morbidity due to lack of first aid care in crucial moments. Training with playing role is suggested for this purpose.

Kinetics study of palm oil hydrolysis using immobilized lipase Candida rugosa in packed bed reactor.

PubMed

Min, C S; Bhatia, S; Kamaruddin, A H

1999-01-01

Continuous hydrolysis of palm oil triglyceride in organic solvent using immobilized Candida rugosa on the Amberlite MB-1 as a source of immobilized lipase was studied in packed bed reactor. The enzymatic kinetics of hydrolysis reaction was studied by changing the substrate concentration, reaction temperature and residence time(tau) in the reactor. At 55 degrees C, the optimum water concentration was found to be 15 % weight per volume of solution (%w/v). The Michaelis-Menten kinetic model was used to obtain the reaction parameters, Km(app) and V max(app). The activation energies were found to be quite low indicating that the lipase-catalyzed process is controlled by diffusion of substrates. The Michaelis-Menten kinetic model was found to be suitable at low water concentration 10-15 %w/v of solution. At higher water concentration, substrate inhibition model was used for data analysis. Reactor operation was found to play an important role in the palm oil hydrolysis kinetic.

Immobilization thresholds of electrofishing relative to fish size

USGS Publications Warehouse

Dolan, C.R.; Miranda, L.E.

2003-01-01

Fish size and electrical waveforms have frequently been associated with variation in electrofishing effectiveness. Under controlled laboratory conditions, we measured the electrical power required by five electrical waveforms to immobilize eight fish species of diverse sizes and shapes. Fish size was indexed by total body length, surface area, volume, and weight; shape was indexed by the ratio of body length to body depth. Our objectives were to identify immobilization thresholds, elucidate the descriptors of fish size that were best associated with those immobilization thresholds, and determine whether the vulnerability of a species relative to other species remained constant across electrical treatments. The results confirmed that fish size is a key variable controlling the immobilization threshold and further suggested that the size descriptor best related to immobilization is fish volume. The peak power needed to immobilize fish decreased rapidly with increasing fish volume in small fish but decreased slowly for fish larger than 75-100 cm 3. Furthermore, when we controlled for size and shape, different waveforms did not favor particular species, possibly because of the overwhelming effect of body size. Many of the immobilization inconsistencies previously attributed to species might simply represent the effect of disparities in body size.

[Immobilization of pectawamorine G10x by gel entrapment].

PubMed

Bogatskiĭ, A V; Davidenko, T I; Areshidze, I V; Gren', T A; Sevast'ianov, O V

1979-01-01

Polyacrylamide gel immobilization of pectawamorine G10x was investigated. Its pectinesterase and polygalacturonase activity and stability in storage were measured. The degree of pectawamorine binding during gel immobilization was 80--90%, 55% of initial activity being retained. Thermal stability of the immobilized and native preparations was equal. Pectinesterase activity of the gel immobilized enzyme increased during storage.

Solvent Stability Study with Thermodynamic Analysis and Superior Biocatalytic Activity of Burkholderia cepacia Lipase Immobilized on Biocompatible Hybrid Matrix of Poly(vinyl alcohol) and Hypromellose.

PubMed

Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

2014-12-26

In the present study, we have synthesized a biocompatible hybrid carrier of hypromellose (HY) and poly(vinyl alcohol) (PVA) for immobilization of Burkholderia cepacia lipase (BCL). The immobilized biocatalyst HY:PVA:BCL was subjected to determination of half-life time (τ) and deactivation rate constant (K(D)) in various organic solvents. Biocatalyst showed higher τ-value in a nonpolar solvent like cyclohexane (822 h) as compared to that of a polar solvent such as acetone (347 h), which signifies better compatibility of biocatalyst in the nonpolar solvents. Furthermore, the K(D)-value was found to be less in cyclohexane (0.843 × 10(-3)) as compared to acetone (1.997 × 10(-3)), indicating better stability in the nonpolar solvents. Immobilized-BCL (35 mg) was sufficient to achieve 99% conversion of phenethyl butyrate (natural constituent of essential oils and has wide industrial applications) using phenethyl alcohol (2 mmol) and vinyl butyrate (6 mmol) at 44 °C in 3 h. The activation energy (E(a)) was found to be lower for immobilized-BCL than crude-BCL, indicating better catalytic efficiency of immobilized lipase BCL. The immobilized-BCL reported 6-fold superior biocatalytic activity and 8 times recyclability as compared to crude-BCL. Improved catalytic activity of immobilized enzyme in nonpolar media was also supported by thermodynamic activation parameters such as enthalpy (ΔH(⧧)), entropy (ΔS(⧧)) and Gibb's free energy (ΔG(⧧)) study, which showed that phenethyl butyrate synthesis catalyzed by immobilized-BCL was feasible as compared to crude-BCL. The present work explains a thermodynamic investigation and superior biocatalytic activity for phenethyl butyrate synthesis using biocompatible immobilized HY:PVA:BCL in nonaqueous media for the first time.

Accumulation of uranium by immobilized persimmon tannin

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

Sakaguchi, Takashi; Nakajima, Akira

1994-01-01

We have discovered that the extracted juice of unripe astringent persimmon fruit, designated as kakishibu or shibuol, has an extremely high affinity for uranium. To develop efficient adsorbents for uranium, we tried to immobilize kakishibu (persimmon tannin) with various aldehydes and mineral acids. Persimmon tannin immobilized with glutaraldehyde can accumulate 1.71 g (14 mEq U) of uranium per gram of the adsorbent. The uranium accumulating capacity of this adsorbent is several times greater than that of commercially available chelating resins (2-3 mEq/g). Immobilized persimmon tannin has the most favorable features for uranium recovery; high selective adsorption ability, rapid adsorption rate,more » and applicability in both column and batch systems. The uranium retained on immobilized persimmon tannin can be quantitatively and easily eluted with a very dilute acid, and the adsorbent can thus be easily recycled in the adsorption-desorption process. Immobilized persimmon tannin also has a high affinity for thorium. 23 refs., 13 figs., 7 tabs.« less

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.

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).

Short-duration electrical immobilization of lake trout

USGS Publications Warehouse

Gaikowski, Mark P.; Gingerich, William H.; Gutreuter, Steve

2001-01-01

Chemical anesthetics induce stress responses, and most leave residues in fish tissues that require a certain withdrawal time before the animal can be released into the environment. Therefore, alternatives are needed in cases when fish must be released immediately, for example, during egg-collecting operations or after implanting elastomer tags. To evaluate pulsed direct current as an alternative method of immobilization, individual lake trout Salvelinus namaycush were electrically immobilized using various pulsed-DC voltage gradients and shock durations. Duration of opercular recovery and narcosis were measured for individual fish. Fish were euthanized 24 h after electrical immobilization and processed for lateral radiograph analysis and assessment of perivertebral hemorrhaging by dissection. Survival of lake trout after electrical immobilization at 0.6 V/cm for 30 or 40 s or 0.8 V/cm for 5 or 15 s was monitored for 81 or 84 d after immobilization. Mean narcosis duration increased with voltage gradient and shock duration. Larger fish had longer periods of narcosis at the same combination of voltage gradient and shock duration. Radiological evaluation indicated that 9 of 28 fish in the oldest age-class tested had detectable injuries of the vertebral column, but all but one were in the lowest injury category. Although vertebral column injuries were observed in most small fish, the majority of vertebral column injuries were minor compressions involving two to seven vertebrae. Of the 82 lake trout electrically immobilized to assess long-term survival, only 5 died (6%). Our data suggest that lake trout could be electrically immobilized for a sufficient period to allow field workers to collect length and weight data and implant visible implant tags or colored elastomer tags. The technique we used, however, is probably not appropriate for procedures that require immobilization for more than 2a??3 min.

Comparative study of thermostability and ester synthesis ability of free and immobilized lipases on cross linked silica gel.

PubMed

Kumari, Annapurna; Mahapatra, Paramita; Kumar, Garlapati Vijay; Banerjee, Rintu

2008-06-01

A novel support has been utilized for immobilization of lipase, which was prepared by amination of silica with ethanolamine followed by cross linking with glutaraldehyde. Lipases from Rhizopus oryzae 3562 and Enterobacter aerogenes were immobilized on activated silica gel, where they retained 60 and 50% of respective original activity. The thermal stability of the immobilized lipases was significantly improved in comparison to the free forms while the pH stability remained unchanged. E. aerogenes and R. oryzae 3562 lipases retained 75 and 97% of respective initial activity on incubation at 90 degrees C, whereas both the free forms became inactive at this temperature. The conversion yield of isoamyl acetate was found to be higher with the immobilized fungal (90 vs. 21%) and bacterial lipases (64 vs. 18%) than the respective free forms. Immobilized R. oryzae 3562 lipases retained 50% activity for isoamyl acetate synthesis up to ten cycles whereas it was eight cycles for E. aerogenes.

Effect of limb immobilization on skeletal muscle

NASA Technical Reports Server (NTRS)

Booth, F. W.

1982-01-01

Current knowledge and questions remaining concerning the effects of limb immobilization on skeletal muscle is reviewed. The most dramatic of these effects is muscle atrophy, which has been noted in cases of muscles fixed at or below their resting length. Immobilization is also accompanied by a substantial decrease in motoneuronal discharges, which results in the conversion of slow-twitch muscle to muscle with fast-twitch characteristics. Sarcolemma effects include no change or a decrease in resting membrane potential, the appearance of extrajunctional acetylcholine receptors, and no change in acetylcholinesterase activity. Evidence of changes in motoneuron after hyperpolarization characteristics suggests that the muscle inactivity is responsible for neuronal changes, rather than vice versa. The rate of protein loss from atrophying muscles is determined solely by the first-order rate constant for degradation. Various other biochemical and functional changes have been noted, including decreased insulin responsiveness and protein synthesis. The model of limb immobilization may also be useful for related studies of muscle adaptation.

Immobilized enzymes in blood plasma exchangers via radiation grafting

NASA Astrophysics Data System (ADS)

Gombotz, Wayne; Hoffman, Allan; Schmer, Gottfried; Uenoyama, Satoshi

The enzyme asparaginase was immobilized onto a porous hollow polypropylene (PP) fiber blood plasma exchange device for the treatment of acute lymphocytic leukemia. The devices were first radiation grafted with polymethacrylic acid (poly(MAAc)). This introduces carboxyl groups onto the surface of the fibers. Several variables were studied in the grafting reaction including the effects of solvent type and monomer concentration. The carboxyl groups were activated with N-hydroxy succinimide (NHS) using carbodiimide chemistry. Asparaginase was then covalently immobilized on the activated surfaces. Quantitative relationships were found relating the percent graft to the amount of immobilized enzyme which was active. The enzyme reactor was tested both in vitro and in vivo using a sheep as an animal model.

Immobilization of Cd in landfill-leachate-contaminated soil with cow manure compost as soil conditioners: A laboratory study.

PubMed

Liao, Zhuwei; Wang, Jia; Wan, Rui; Xi, Shuang; Chen, Zhuqi; Chen, Zhulei; Yu, Yingjian; Long, Sijie; Wang, Huabin

2016-12-01

Introducing cow manure compost as an amendment in landfill-leachate-contaminated soils is proved to be an effective technique for the immobilization of Cd in this study. Landfill-leachate-contaminated soil was collected from an unlined landfill in China and amended with a different blending quantity of cow manure compost (0, 12, 24, 36, and 48 g per 200 g soil), which was made by mixing cow manure and chaff at a ratio of 1/1 and maturing for 6 months. pH values of five different blending quantity mixtures increased by 0.2-0.4, and the organic matter levels increased by 2.5-7%, during a remediation period of 5 weeks. Four fractions of Cd named exchangeable Cd, reducible Cd, oxidizable Cd, and residual Cd in soil were respectively analyzed by a sequential extraction procedure. Introducing the cow manure compost application resulted in more than 40% lower exchangeable Cd but a higher concentration of oxidizable Cd in soils, and mass balance results showed nearly no Cd absorption by applied material, indicating that transformation of exchangeable Cd into oxidization forms was the main mechanism of Cd immobilization when cow manure compost was used as an amendment. The Pearson correlation showed that increasing of pH values significantly improved the efficiency of Cd immobilization, with a correlation coefficiency of 0.940 (p < 0.05). This is the first attempt at heavy metal immobilization in landfill-leachate-contaminated soil by cow manure compost, and findings of this work can be integrated to guide the application. Addition of cow manure compost (CMC) was effective in reducing exchangeable Cd in landfill-leachate-contaminated soils (LLCS). The immobilization effect of Cd was mainly assigned to the redistribution of labile soil Cd. Organic matter (OM) and pH value increased with CMC application. The pH values were more sensitive to Cd immobilization efficiency. It was proved that CMC can be safely and effectively used for the restoration of LLCS.

Polishing of POME by Chlorella sp. in suspended and immobilized system

NASA Astrophysics Data System (ADS)

Lahin, F. A.; Sarbatly, R.; Suali, E.

2016-06-01

The effect of using suspended and immobilized growth of Chlorella sp. to treat POME was studied. Cotton and nylon ropes were used as the immobilization material in a rotating microalgae biofilm reactor. The result showed that POME treated in suspended growth system was able to remove 81.9% and 55.5% of the total nitrogen (TN) and total phosphorus (TP) respectively. Whereas the immobilized system showed lower removal of 77.22% and 53.02% for TN and TP. Lower performance of immobilized microalgae is due to the limited light penetration and supply of CO2 inside the immobilization materials. The rotating microalgae biofilm reactor was able to reduce the biochemical oxygen demand (BOD) to 90 mg/L and chemical oxygen demand (COD) to 720 mg/L. Higher BOD and COD reading were obtained in suspended growth due to the presence of small number of microalgae cell in the samples. This study shows that suspended growth system is able to remove higher percentages of nitrogen and phosphorus. However, an efficient separation method such as membrane filtration is required to harvest the cultivated microalgae cell to avoid organic matter release into water bodies.

Yeast Immobilization Systems for Alcoholic Wine Fermentations: Actual Trends and Future Perspectives

PubMed Central

Moreno-García, Jaime; García-Martínez, Teresa; Mauricio, Juan C.; Moreno, Juan

2018-01-01

Yeast immobilization is defined as the physical confinement of intact cells to a region of space with conservation of biological activity. The use of these methodologies for alcoholic fermentation (AF) offers many advantages over the use of the conventional free yeast cell method and different immobilization systems have been proposed so far for different applications, like winemaking. The most studied methods for yeast immobilization include the use of natural supports (e.g., fruit pieces), organic supports (e.g., alginate), inorganic (e.g., porous ceramics), membrane systems, and multi-functional agents. Some advantages of the yeast-immobilization systems include: high cell densities, product yield improvement, lowered risk of microbial contamination, better control and reproducibility of the processes, as well as reuse of the immobilization system for batch fermentations and continuous fermentation technologies. However, these methods have some consequences on the behavior of the yeasts, affecting the final products of the fermentative metabolism. This review compiles current information about cell immobilizer requirements for winemaking purposes, the immobilization methods applied to the production of fermented beverages to date, and yeast physiological consequences of immobilization strategies. Finally, a recent inter-species immobilization methodology has been revised, where yeast cells are attached to the hyphae of a Generally Recognized As Safe fungus and remain adhered following loss of viability of the fungus. The bio-capsules formed with this method open new and promising strategies for alcoholic beverage production (wine and low ethanol content beverages). PMID:29497415

Immobilization of ammonia-oxidizing bacteria by polyvinyl alcohol and sodium alginate.

PubMed

Dong, Yuwei; Zhang, Yanqiu; Tu, Baojun

Ammonia-oxidizing bacteria were immobilized by polyvinyl alcohol (PVA) and sodium alginate. The immobilization conditions and ammonia oxidation ability of the immobilized bacteria were investigated. The following immobilization conditions were observed to be optimal: PVA, 12%; sodium alginate, 1.1%; calcium chloride, 1.0%; inoculum concentration, 1.3 immobilized balls/mL of immobilized medium; pH, 10; and temperature, 30°C. The immobilized ammonia-oxidizing bacteria exhibited strong ammonia oxidation ability even after being recycled four times. The ammonia nitrogen removal rate of the immobilized ammonia-oxidizing bacteria reached 90.30% under the optimal immobilization conditions. When compared with ammonia-oxidizing bacteria immobilized by sodium alginate alone, the bacteria immobilized by PVA and sodium alginate were superior with respect to pH resistance, the number of reuses, material cost, heat resistance, and ammonia oxidation ability. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Bystander first aid in trauma - prevalence and quality: a prospective observational study.

PubMed

Bakke, H K; Steinvik, T; Eidissen, S-I; Gilbert, M; Wisborg, T

2015-10-01

Bystander first aid and basic life support can likely improve victim survival in trauma. In contrast to bystander first aid and out-of-hospital cardiac arrest, little is known about the role of bystanders in trauma response. Our aim was to determine how frequently first aid is given to trauma victims by bystanders, the quality of this aid, the professional background of first-aid providers, and whether previous first-aid training affects aid quality. We conducted a prospective 18-month study in two mixed urban-rural Norwegian counties. The personnel on the first ambulance responding to trauma calls assessed and documented first aid performed by bystanders using a standard form. A total of 330 trauma calls were included, with bystanders present in 97% of cases. Securing an open airway was correctly performed for 76% of the 43 patients in need of this first-aid measure. Bleeding control was provided correctly for 81% of 63 patients for whom this measure was indicated, and prevention of hypothermia for 62% of 204 patients. Among the first-aid providers studied, 35% had some training in first aid. Bystanders with documented first-aid training gave better first aid than those where first-aid training status was unknown. A majority of the trauma patients studied received correct pre-hospital first aid, but still there is need for considerable improvement, particularly hypothermia prevention. Previous first-aid training seems to improve the quality of first aid provided. The effect on patient survival needs to be investigated. © 2015 The Authors. The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Invertase immobilization onto radiation-induced graft copolymerized polyethylene pellets

NASA Astrophysics Data System (ADS)

de Queiroz, Alvaro Antonio Alencar; Vitolo, Michele; de Oliveira, Rômulo Cesar; Higa, Olga Zazuco

1996-06-01

The graft copolymer poly(ethylene-g-acrylic acid) (LDPE-g-AA) was prepared by radiation-induced graft copolymerization of acrylic acid onto low density polyethylene (LDPE) pellets, and characterized by infrared photoacoustic spectroscopy and scanning electron microscopy (SEM). The presence of the grafted poly(acrylic acid) (PAA) was established. Invertase was immobilized onto the graft polymer and the thermodynamic parameters of the soluble and immobilized enzyme were determined. The Michaelis constant, Km, and the maximum reaction velocity, Vmax, were determined for the free and the immobilized invertase. The Michaelis constant, Km was larger for the immobilized invertase than for the free enzyme, whereas Vmax was smaller for the immobilized invertase. The thermal stability of the immobilized invertase was higher than that of the free enzyme.

Modification of silicon nitride surfaces with GOPES and APTES for antibody immobilization: computational and experimental studies

NASA Astrophysics Data System (ADS)

Dien To, Thien; Nguyen, Anh Tuan; Nhat Thanh Phan, Khoa; Thu Thi Truong, An; Doan, Tin Chanh Duc; Mau Dang, Chien

2015-12-01

Chemical modification of silicon nitride (SiN) surfaces by silanization has been widely studied especially with 3-(aminopropyl)triethoxysilane (APTES) and 3-(glycidyloxypropyl) dimethylethoxysilane (GOPES). However few reports performed the experimental and computational studies together. In this study, surface modification of SiN surfaces with GOPES and APTES covalently bound with glutaraldehyde (GTA) was investigated for antibody immobilization. The monoclonal anti-cytokeratin-FITC (MACF) antibody was immobilized on the modified SiN surfaces. The modified surfaces were characterized by water contact angle measurements, atomic force microscopy and fluorescence microscopy. The FITC-fluorescent label indicated the existence of MACF antibody on the SiN surfaces and the efficiency of the silanization reaction. Absorption of APTES and GOPES on the oxidized SiN surfaces was computationally modeled and calculated by Materials Studio software. The computational and experimental results showed that modification of the SiN surfaces with APTES and GTA was more effective than the modification with GOPES.

Immobilization of laccase of Pycnoporus sanguineus CS43.

PubMed

Gonzalez-Coronel, Luis A; Cobas, Marta; Rostro-Alanis, Magdalena de J; Parra-Saldívar, Roberto; Hernandez-Luna, Carlos; Pazos, Marta; Sanromán, M Ángeles

2017-10-25

Laccase from Pycnoporus sanguineus CS43 was successfully immobilized onto Immobead-150 and Eupergit-C by covalent binding and by entrapment in LentiKats. The highest immobilization was onto Immobead-150 (97.1±1.2%) compared to the other supports, LentiKats (89±1.1%) and Eupergit-C (83.2±1.4%). All three immobilized enzyme systems showed increased thermostability and better mechanical properties than free laccase. Moreover, after 5 cycles of reuse of these systems, 90% of initial laccase activity was retained. Immobead-150 and LentiKats systems exhibited the highest efficiencies in removal of m-cresol under the combined actions of biodegradation and adsorption, while laccase entrapped in LentiKats showed a high ability for degradation of m-cresol within 24h. In addition, the typical Michaelis-Menten enzymatic model effectively described the kinetic profile of m-cresol degradation by the enzyme entrapped in LentiKats. Based on the results obtained in the present study, it can be established that the immobilized biocatalysts developed here possess significant potential for wastewater treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

Oriented antibody immobilization on self-assembled monolayers applied as impedance biosensors

NASA Astrophysics Data System (ADS)

Tsugimura, Kaiki; Ohnuki, Hitoshi; Wu, Haiyun; Endo, Hideaki; Tsuya, Daiju; Izumi, Mitsuru

2017-11-01

Oriented immobilization of antibodies on a sensor chip is crucial for enhancing both the sensitivity and antigen-binding capacity of immunosensors. Here, we report a comparative study of the effect of oriented and random antibody immobilization on the binding efficiency by electrochemical impedance spectroscopy (EIS). Oriented immobilization of anti-myoglobin immunoglobulin G (anti-Myo IgG) was achieved by bonding to an Fc receptor of protein G (PrG) on a self-assembled monolayer (SAM), which results in the myoglobin (Myo) binding sites being exposed outside the sensing surface. Random immobilization of anti-Myo IgG was achieved by direct covalent attachment to the SAM surface. Both immobilizations were applied to interdigitated electrodes to enhance the electrochemical signal, and the Myo biosensor performance was then evaluated by a series of EIS measurements. We found that (i) the rate of the normalized charge transfer resistance for the oriented sample was 3 times higher than that for the random sample and (ii) the detection limit was 0.001 ng/mL, which is the lowest recorded detection limit among Myo immunosensors based on EIS. These findings indicate that oriented antibody immobilization is crucial for preparing highly sensitive EIS-based biosensors.

Gold and silver nanoparticles for biomolecule immobilization and enzymatic catalysis

PubMed Central

2012-01-01

In this work, a simple method for alcohol synthesis with high enantiomeric purity was proposed. For this, colloidal gold and silver surface modifications with 3-mercaptopropanoic acid and cysteamine were used to generate carboxyl and amine functionalized gold and silver nanoparticles of 15 and 45 nm, respectively. Alcohol dehydrogenase from Thermoanaerobium brockii (TbADH) and its cofactor (NADPH) were physical and covalent (through direct adsorption and using cross-linker) immobilized on nanoparticles' surface. In contrast to the physical and covalent immobilizations that led to a loss of 90% of the initial enzyme activity and 98% immobilization, the use of a cross-linker in immobilization process promoted a loss to 30% of the initial enzyme activity and >92% immobilization. The yield of NADPH immobilization was about 80%. The best results in terms of activity were obtained with Ag-citr nanoparticle functionalized with carboxyl groups (Ag-COOH), Au-COOH(CTAB), and Au-citr functionalized with amine groups and stabilized with CTAB (Au-NH2(CTAB)) nanoparticles treated with 0.7% and 1.0% glutaraldehyde. Enzyme conformation upon immobilization was studied using fluorescence and circular dichroism spectroscopies. Shift in ellipticity at 222 nm with about 4 to 7 nm and significant decreasing in fluorescence emission for all bioconjugates were observed by binding of TbADH to silver/gold nanoparticles. Emission redshifting of 5 nm only for Ag-COOH-TbADH bioconjugate demonstrated change in the microenvironment of TbADH. Enzyme immobilization on glutaraldehyde-treated Au-NH2(CTAB) nanoparticles promotes an additional stabilization preserving about 50% of enzyme activity after 15 days storage. Nanoparticles attached-TbADH-NADPH systems were used for enantioselective (ee > 99%) synthesis of (S)-7-hydroxy-2-tetralol. PMID:22655978

Gold and silver nanoparticles for biomolecule immobilization and enzymatic catalysis.

PubMed

Petkova, Galina A; Záruba, Capital Ka Cyrillicamil; Zvátora, Pavel; Král, Vladimír

2012-06-01

In this work, a simple method for alcohol synthesis with high enantiomeric purity was proposed. For this, colloidal gold and silver surface modifications with 3-mercaptopropanoic acid and cysteamine were used to generate carboxyl and amine functionalized gold and silver nanoparticles of 15 and 45 nm, respectively. Alcohol dehydrogenase from Thermoanaerobium brockii (TbADH) and its cofactor (NADPH) were physical and covalent (through direct adsorption and using cross-linker) immobilized on nanoparticles' surface. In contrast to the physical and covalent immobilizations that led to a loss of 90% of the initial enzyme activity and 98% immobilization, the use of a cross-linker in immobilization process promoted a loss to 30% of the initial enzyme activity and >92% immobilization. The yield of NADPH immobilization was about 80%. The best results in terms of activity were obtained with Ag-citr nanoparticle functionalized with carboxyl groups (Ag-COOH), Au-COOH(CTAB), and Au-citr functionalized with amine groups and stabilized with CTAB (Au-NH2(CTAB)) nanoparticles treated with 0.7% and 1.0% glutaraldehyde. Enzyme conformation upon immobilization was studied using fluorescence and circular dichroism spectroscopies. Shift in ellipticity at 222 nm with about 4 to 7 nm and significant decreasing in fluorescence emission for all bioconjugates were observed by binding of TbADH to silver/gold nanoparticles. Emission redshifting of 5 nm only for Ag-COOH-TbADH bioconjugate demonstrated change in the microenvironment of TbADH. Enzyme immobilization on glutaraldehyde-treated Au-NH2(CTAB) nanoparticles promotes an additional stabilization preserving about 50% of enzyme activity after 15 days storage. Nanoparticles attached-TbADH-NADPH systems were used for enantioselective (ee > 99%) synthesis of (S)-7-hydroxy-2-tetralol.

Highly efficient method towards in situ immobilization of invertase using cryogelation.

PubMed

Olcer, Zehra; Ozmen, Mehmet Murat; Sahin, Zeynep M; Yilmaz, Faruk; Tanriseven, Aziz

2013-12-01

A novel method was developed for the immobilization of Saccharomyces cerevisiae invertase within supermacroporous polyacrylamide cryogel and was used to produce invert sugar. First, the cross-linking of invertase with soluble polyglutaraldehyde (PGA) was carried out prior to immobilization in order to increase the bulkiness of invertase and thus preventing the leakage of the cross-linked enzyme after immobilization by entrapment. And then, in situ immobilization of PGA cross-linked invertase within cryogel synthesis was achieved by free radical polymerization in semi-frozen state. The method resulted in 100 % immobilization and 74 % activity yields. The immobilized invertase retained all the initial activity for 30 days and 30 batch reactions. Immobilization had no effect on optimum temperature and it was 60 °C for both free and immobilized enzyme. However, optimum pH was affected upon immobilization. Optimum pH values for free and immobilized enzyme were 4.5 and 5.0, respectively. The immobilized enzyme was more stable than the free enzyme at high pH and temperatures. The kinetic parameters for free and immobilized invertase were also determined. The newly developed method is simple yet effective and could be used for the immobilization of some other enzymes and microorganisms.

Silica-Immobilized Enzyme Reactors (Postprint)

DTIC Science & Technology

2007-09-01

mode of action of drugs such as aspirin and ibuprofen .[61] Serotonin reuptake inhibitors and monoamine oxidase inhibitors can function as...immobilizing PGA onto chromatography supports and using the enantiomeric selectivity of the enzyme to resolve racemic mixtures.[100] Immobilization onto...column. J. Chroma- togr. B. Biomed. Sci. Appl. 2001, 753, 375–383. 37. Jadaud, P.; Wainer, I.W. The stereochemical resolution of the enantiomers of

Covalent immobilization of β-glucosidase on magnetic particles for lignocellulose hydrolysis.

PubMed

Alftrén, Johan; Hobley, Timothy John

2013-04-01

β-Glucosidase hydrolyzes cellobiose to glucose and is an important enzyme in the consortium used for hydrolysis of cellulosic and lignocellulosic feedstocks. In the present work, β-glucosidase was covalently immobilized on non-porous magnetic particles to enable re-use of the enzyme. It was found that particles activated with cyanuric chloride and polyglutaraldehyde gave the highest bead-related immobilized enzyme activity when tested with p-nitrophenyl-β-D-glucopyranoside (104.7 and 82.2 U/g particles, respectively). Furthermore, the purified β-glucosidase preparation from Megazyme gave higher bead-related enzyme activities compared to Novozym 188 (79.0 and 9.8 U/g particles, respectively). A significant improvement in thermal stability was observed for immobilized enzyme compared to free enzyme; after 5 h (at 65 °C), 36 % of activity remained for the former, while there was no activity in the latter. The performance and recyclability of immobilized β-glucosidase on more complex substrate (pretreated spruce) was also studied. It was shown that adding immobilized β-glucosidase (16 U/g dry matter) to free cellulases (8 FPU/g dry matter) increased the hydrolysis yield of pretreated spruce from ca. 44 % to ca. 65 %. In addition, it was possible to re-use the immobilized β-glucosidase in the spruce and retain activity for at least four cycles. The immobilized enzyme thus shows promise for lignocellulose hydrolysis.

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.

Histomorphometric analysis of the response of rat skeletal muscle to swimming, immobilization and rehabilitation.

PubMed

Nascimento, C C F; Padula, N; Milani, J G P O; Shimano, A C; Martinez, E Z; Mattiello-Sverzut, A C

2008-09-01

The objective of the present study was to determine to what extent, if any, swimming training applied before immobilization in a cast interferes with the rehabilitation process in rat muscles. Female Wistar rats, mean weight 260.52 +/- 16.26 g, were divided into 4 groups of 6 rats each: control, 6 weeks under baseline conditions; trained, swimming training for 6 weeks; trained-immobilized, swimming training for 6 weeks and then immobilized for 1 week; trained-immobilized-rehabilitated, swimming training for 6 weeks, immobilized for 1 week and then remobilized with swimming for 2 weeks. The animals were then sacrificed and the soleus and tibialis anterior muscles were dissected, frozen in liquid nitrogen and processed histochemically (H&E and mATPase). Data were analyzed statistically by the mixed effects linear model (P < 0.05). Cytoarchitectural changes such as degenerative characteristics in the immobilized group and regenerative characteristics such as centralized nucleus, fiber size variation and cell fragmentation in the groups submitted to swimming were more significant in the soleus muscle. The diameters of the lesser soleus type 1 and type 2A fibers were significantly reduced in the trained-immobilized group compared to the trained group (P < 0.001). In the tibialis anterior, there was an increase in the number of type 2B fibers and a reduction in type 2A fibers when trained-immobilized rats were compared to trained rats (P < 0.001). In trained-immobilized-rehabilitated rats, there was a reduction in type 2B fibers and an increase in type 2A fibers compared to trained-immobilized rats (P < 0.009). We concluded that swimming training did not minimize the deleterious effects of immobilization on the muscles studied and that remobilization did not favor tissue re-adaptation.

Quantitative structure-retention relationship studies with immobilized artificial membrane chromatography II: partial least squares regression.

PubMed

Li, Jie; Sun, Jin; He, Zhonggui

2007-01-26

We aimed to establish quantitative structure-retention relationship (QSRR) with immobilized artificial membrane (IAM) chromatography using easily understood and obtained physicochemical molecular descriptors and to elucidate which descriptors are critical to affect the interaction process between solutes and immobilized phospholipid membranes. The retention indices (logk(IAM)) of 55 structurally diverse drugs were determined on an immobilized artificial membrane column (IAM.PC.DD2) directly or obtained by extrapolation method for highly hydrophobic compounds. Ten simple physicochemical property descriptors (clogP, rings, rotatory bond, hydro-bond counting, etc.) of these drugs were collected and used to establish QSRR and predict the retention data by partial least squares regression (PLSR). Five descriptors, clogP, rotatory bond (RotB), rings, molecular weight (MW) and total surface area (TSA), were reserved by using the Variable Importance for Projection (VIP) values as criterion to build the final PLSR model. An external test set was employed to verify the QSRR based on the training set with the five variables, and QSRR by PLSR exhibited a satisfying predictive ability with R(p)=0.902 and RMSE(p)=0.400. Comparison of coefficients of centered and scaled variables by PLSR demonstrated that, for the descriptors studied, clogP and TSA have the most significant positive effect but the rotatable bond has significant negative effect on drug IAM chromatographic retention.

The immobilization of lipase on PVDF-co-HFP membrane

NASA Astrophysics Data System (ADS)

Kayhan, Naciye; Eyüpoǧlu, Volkan; Adem, Şevki

2016-04-01

Lipase is an enzyme having a lot of different industrial applications such as biodiesel production, biopolymer synthesis, enantiopure pharmaceutical productions, agrochemicals, etc. Its immobilized form on different substances is more conventional and useful than its free form. Supporting material was prepared using PVDF-co-HFP in laboratory conditions and attached 1,4-diaminobutane (DA) and epichlorohydrin (EPI) ligands to the membrane to immobilize lipase enzyme. The immobilization conditions such as enzyme amount, pH, the concentration of salt, thermal stability and activity were stabilized for our experimental setup. Then, biochemical characterizations were performed on immobilized lipase PVDF-co-HFP regarding optimal pH activity, temperature and thermal stability. Also, the desorption ratios of immobilized enzyme in two different pathway were investigated to confirm immobilization stability for 24 hours.

Utilization of Negotiated Tuition Aid Benefits. A Summary of the Study "Where Are the Women? A Study of the Underutilization of Tuition Aid Plans."

ERIC Educational Resources Information Center

Abramovitz, Mimi

A chapter from the forthcoming book, "Practitioners' Guide to Education for Working Adults," describes a year-long study to explore the low utilization of tuition aid plans in three unionized companies. The research has shown that the use of tuition aid programs is in inverse ratio to need. Workers who tend to utilize tuition aid are those who…

Stabilization of α-amylase by using anionic surfactant during the immobilization process

NASA Astrophysics Data System (ADS)

El-Batal, A. I.; Atia, K. S.; Eid, M.

2005-10-01

This work describes the entrapment of α-amylase into butylacrylate-acrylic acid copolymer (BuA/AAc) using γ irradiation. The effect of an anionic surfactant (AOT), the reuse efficiency, and kinetic behavior of immobilized α-amylase were studied. Covering of α-amylase with bis-(2-ethylhexyl)sulfosuccinate sodium salt (AOT) made the enzyme more stable than the uncovered form. The hydrolytic activity of the pre-coated immobilized α-amylase was increased below the critical micelle concentration (cmc) (10 mmol/L). The results showed an increase in the relative activity with increase in the degree of hydration. The pre-coated immobilized α-amylase showed a higher k/K and lower activation energy compared to the free and uncoated-immobilized preparation, respectively. The results suggest that the immobilization of α-amylase is a potentially useful approach for commercial starch hydrolysis in two-phase systems.

Evaluation of oriented lysozyme immobilized with monoclonal antibody

NASA Astrophysics Data System (ADS)

Aoyagi, Satoka; Okada, Keigo; Shigyo, Ayako; Man, Naoki; Karen, Akiya

2008-12-01

The orientation of a lysozyme immobilized with a monoclonal antibody was evaluated based on determination of the uppermost surface structure using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Specific peaks of the oriented lysozyme immobilized with monoclonal anti-lysozyme antibody were obtained in comparison with reference samples, non-oriented immobilized lysozyme and immobilized anti-lysozyme antibody. All samples were freeze-dried before TOF-SIMS measurement, and then each sample was measured using TOF-SIMS with a bismuth cluster ion source. TOF-SIMS spectra were analyzed to select peaks specific to the oriented immobilized lysozyme as well as to identify their chemical formula and ensemble of amino acids. The possible chemical formulae of the lysozyme fragments were then investigated with an element matching program and a residue matching program. The results from TOF-SIMS spectra analysis were compared to the amino acid sequence of the lysozyme and its three-dimensional structure registered in the protein data bank. Finally, the fragment-ion-generating regions of the oriented immobilized lysozyme were determined based on the suggested residues and the three-dimensional structure.

Herbaceous plants as filters: immobilization of particulates along urban street corridors.

PubMed

Weber, Frauke; Kowarik, Ingo; Säumel, Ina

2014-03-01

Among air pollutants, particulate matter (PM) is considered to be the most serious threat to human health. Plants provide ecosystem services in urban areas, including reducing levels of PM by providing a surface for deposition and immobilization. While previous studies have mostly addressed woody species, we focus on herbaceous roadside vegetation and assess the role of species traits such as leaf surface roughness or hairiness for the immobilization of PM. We found that PM deposition patterns on plant surfaces reflect site-specific traffic densities and that strong differences in particulate deposition are present among species. The amount of immobilized PM differed according to particle type and size and was related to specific plant species traits. Our study suggests that herbaceous vegetation immobilizes a significant amount of the air pollutants relevant to human health and that increasing biodiversity of roadside vegetation supports air filtration and thus healthier conditions along street corridors. Copyright © 2013 Elsevier Ltd. All rights reserved.

A Study of the Combined Use of a Hearing Aid and Tactual Aid in an Adult with Profound Hearing Loss

ERIC Educational Resources Information Center

Reed, Charlotte M.; Delhorne, Lorraine A.

2006-01-01

This study examined the benefits of the combined used of a hearing aid and tactual aid to supplement lip-reading in the reception of speech and for the recognition of environmental sounds in an adult with profound hearing loss. Speech conditions included lip-reading alone (L), lip-reading + tactual aid (L+TA) lip-reading + hearing aid (L+HA) and…

Short-Term Limb Immobilization Affects Cognitive Motor Processes

ERIC Educational Resources Information Center

Toussaint, Lucette; Meugnot, Aurore

2013-01-01

We examined the effects of a brief period of limb immobilization on the cognitive level of action control. A splint placed on the participants' left hand was used as a means of immobilization. We used a hand mental rotation task to investigate the immobilization-induced effects on motor imagery performance (Experiments 1 and 2) and a number mental…

Recovery of skeletal muscle after 3 mo of hindlimb immobilization in rats

NASA Technical Reports Server (NTRS)

Booth, F. W.; Seider, M. J.

1979-01-01

During immobilization, skeletal muscle undergoes decreases in size and strength with concomitant atrophic and degenerative changes in slow-twitch muscle fibers. Currently there are no objective data in slow-twitch muscle demonstrating recovery of biochemical or physiological indices following termination of immobilization. The purpose of this study was to determine whether the soleus, a slow-twitch muscle, could recover normal biochemical or physiological levels following termination of immobilization. Adenosine triphosphate, glycogen, and protein concentration (mg/g wet wt) all significantly decreased following 90 days of hindlimb immobilization, but these three values returned to control levels by the 60th recovery day. Similarly, soleus muscle wet weight and protein content (mg protein/muscle) returned to control levels by the 14th recovery day. In contrast, maximal isometric tension did not return to normal until the 120th day. These results indicate that following muscular atrophy, which was achieved through 90 days of hindlimb immobilization, several biochemical and physiological values in skeletal muscle are recovered at various times after the end of immobilization.

Immobilization of bacterial proteases on water-solved polymer by means of electron beam

NASA Astrophysics Data System (ADS)

Gonchar, A. M.; Auslender, V. L.

1996-12-01

Possibility of electron beam usage for proteases' immobilization on 1,4-polyalkylene oxide (1,4-PAO) was studied to obtain biologically active complex for multi-purpose usage. It is shown that immobilization of Bacillus Subtilis protease takes place due to free-radical linking of enzyme and carrier with formation of mycellium-like structures. Immobilization improves heat resistance of enzyme up to 60°C without substrate and up to 80°C in presence of substrate, widens range of pH activity in comparison with non-immobilized forms. Immobilized proteases do not contain peroxides or long-live radicals. Our results permitted to create technologies for production of medical and veterinary preparations, active components for wool washing agents and leather fabrication technology.

Solid-support immobilization of a "swing" fusion protein for enhanced glucose oxidase catalytic activity.

PubMed

Takatsuji, Yoshiyuki; Yamasaki, Ryota; Iwanaga, Atsushi; Lienemann, Michael; Linder, Markus B; Haruyama, Tetsuya

2013-12-01

The strategic surface immobilization of a protein can add new functionality to a solid substrate; however, protein activity, e.g., enzymatic activity, can be drastically decreased on immobilization onto a solid surface. The concept of a designed and optimized "molecular interface" is herein introduced in order to address this problem. In this study, molecular interface was designed and constructed with the aim of attaining high enzymatic activity of a solid-surface-immobilized a using the hydrophobin HFBI protein in conjunction with a fusion protein of HFBI attached to glucose oxidase (GOx). The ability of HFBI to form a self-organized membrane on a solid surface in addition to its adhesion properties makes it an ideal candidate for immobilization. The developed fusion protein was also able to form an organized membrane, and its structure and immobilized state on a solid surface were investigated using QCM-D measurements. This method of immobilization showed retention of high enzymatic activity and the ability to control the density of the immobilized enzyme. In this study, we demonstrated the importance of the design and construction of molecular interface for numerous purposes. This method of protein immobilization could be utilized for preparation of high throughput products requiring structurally ordered molecular interfaces, in addition to many other applications. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

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.

Immobilization of recombinant vault nanoparticles on solid substrates.

PubMed

Xia, Yun; Ramgopal, Yamini; Li, Hai; Shang, Lei; Srinivas, Parisa; Kickhoefer, Valerie A; Rome, Leonard H; Preiser, Peter R; Boey, Freddy; Zhang, Hua; Venkatraman, Subbu S

2010-03-23

Native vaults are nanoscale particles found abundantly in the cytoplasm of most eukaryotic cells. They have a capsule-like structure with a thin shell surrounding a "hollow" interior compartment. Recombinant vault particles were found to self-assemble following expression of the major vault protein (MVP) in a baculovirus expression system, and these particles are virtually identical to native vaults. Such particles have been recently studied as potential delivery vehicles. In this study, we focus on immobilization of vault particles on a solid substrate, such as glass, as a first step to study their interactions with cells. To this end, we first engineered the recombinant vaults by fusing two different tags to the C-terminus of MVP, a 3 amino acid RGD peptide and a 12 amino acid RGD-strep-tag peptide. We have demonstrated two strategies for immobilizing vaults on solid substrates. The barrel-and-cap structure of vault particles was observed for the first time, by atomic force microscopy (AFM), in a dry condition. This work proved the feasibility of immobilizing vault nanoparticles on a material surface, and the possibility of using vault nanoparticles as localized and sustainable drug carriers as well as a biocompatible surface moiety.

Thermodynamic and kinetic studies on pectinase extracted from Aspergillus aculeatus: Free and immobilized enzyme entrapped in alginate beads.

PubMed

de Oliveira, Rodrigo Lira; da Silva, Osmar Soares; Converti, Attilio; Porto, Tatiana Souza

2018-05-01

The kinetics and thermodynamics of Aspergillus aculeatus pectinase, either free or immobilized in alginate beads, were investigated. Pectinase immobilization ensured an enzyme immobilization yield of 59.71%. The irreversible denaturation of pectinase in both preparations was evaluated at temperatures ranging from 30 to 60 °C. When temperature was raised, the first-order thermal denaturation constant increased from 0.0011 to 0.0231 min -1 for the free enzyme and from 0.0017 to 0.0700 min -1 for the immobilized one, respectively. The results of residual activity tests enabled us to estimate, for denaturation of both free and immobilized pectinase, the activation energy (E ⁎ d  = 85.1 and 101.6 kJ·mol -1 ), enthalpy (82.59 ≤ ΔH ⁎ d  ≤ 82.34 kJ·mol -1 and 99.11 ≤ ΔH ⁎ d  ≤ 98.86 kJ·mol -1 ), entropy (-63.26 ≤ ΔS ⁎ d  ≤ -63.85 J·mol -1 ·K -1 and -5.50 ≤ ΔS ⁎ d  ≤ -5.23 J·mol -1 ·K -1 ) and Gibbs free energy (101.8 ≤ ΔG ⁎ d  ≤ 104.7 kJ·mol -1 and 100.6 ≤ ΔG ⁎ d  ≤ 102.0 kJ·mol -1 ). The integral activity of a continuous system using the free and immobilized enzyme was also predicted, whose results indicated a satisfactory enzyme long-term thermostability in both preparations at temperatures commonly used to clarify juice. These results suggest that both free and immobilized pectinase from A. aculeatus may be profitably exploited in future food industrial applications, with special concern to the immobilized enzyme because of its reusability. Copyright © 2018 Elsevier B.V. All rights reserved.

Covalent immobilization of molecularly imprinted polymer nanoparticles using an epoxy silane.

PubMed

Kamra, Tripta; Chaudhary, Shilpi; Xu, Changgang; Johansson, Niclas; Montelius, Lars; Schnadt, Joachim; Ye, Lei

2015-05-01

Molecularly imprinted polymers (MIPs) can be used as antibody mimics to develop robust chemical sensors. One challenging problem in using MIPs for sensor development is the lack of reliable conjugation chemistry that allows MIPs to be fixed on transducer surface. In this work, we study the use of epoxy silane to immobilize MIP nanoparticles on model transducer surfaces without impairing the function of the immobilized nanoparticles. The MIP nanoparticles with a core-shell structure have selective molecular binding sites in the core and multiple amino groups in the shell. The model transducer surface is functionalized with a self-assembled monolayer of epoxy silane, which reacts with the core-shell MIP particles to enable straightforward immobilization. The whole process is characterized by studying the treated surfaces after each preparation step using atomic force microscopy, scanning electron microscopy, fluorescence microscopy, contact angle measurements and X-ray photoelectron spectroscopy. The microscopy results show that the MIP particles are immobilized uniformly on surface. The photoelectron spectroscopy results further confirm the action of each functionalization step. The molecular selectivity of the MIP-functionalized surface is verified by radioligand binding analysis. The particle immobilization approach described here has a general applicability for constructing selective chemical sensors in different formats. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

TiO₂ beads and TiO₂-chitosan beads for urease immobilization.

PubMed

Ispirli Doğaç, Yasemin; Deveci, Ilyas; Teke, Mustafa; Mercimek, Bedrettin

2014-09-01

The aim of the present study is to synthesize TiO2 beads for urease immobilization. Two different strategies were used to immobilize the urease on TiO2 beads. In the first method (A), urease enzyme was immobilized onto TiO2 beads by adsorption and then crosslinking. In the second method (B), TiO2 beads were coated with chitosan-urease mixture. To determine optimum conditions of immobilization, different parameters were investigated. The parameters of optimization were initial enzyme concentration (0.5; 1; 1.5; 2mg/ml), alginate concentration (1; 2; 3%), glutaraldehyde concentration (1; 2; 3% v/v) and chitosan concentration (2; 3; 4 mg/ml). The optimum enzyme concentrations were determined as 1.5mg/ml for A and 1.0mg/ml for B. The other optimum conditions were found 2.0% (w/v) for alginate concentration (both A and B); 3.0mg/ml for chitosan concentration (B) and 2.0% (v/v) for glutaraldehyde concentration (A). The optimum temperature (20-60°C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4-70°C), pH stability (4.0-9.0), operational stability (0-230 min) and reusability (20 times) were investigated for characterization. The optimum temperatures were 30°C (A), 40°C (B) and 35°C (soluble). The temperature profiles of the immobilized ureases were spread over a large area. The optimum pH values for the soluble urease and immobilized urease prepared by using methods (A) and (B) were found to be 7.5, 7.0, 7.0, respectively. The thermal stabilities of immobilized enzyme sets were studied and they maintained 50% activity at 65°C. However, at this temperature free urease protected only 15% activity. Copyright © 2014 Elsevier B.V. All rights reserved.

Fluctuation correlation models for receptor immobilization

NASA Astrophysics Data System (ADS)

Fourcade, B.

2017-12-01

Nanoscale dynamics with cycles of receptor diffusion and immobilization by cell-external-or-internal factors is a key process in living cell adhesion phenomena at the origin of a plethora of signal transduction pathways. Motivated by modern correlation microscopy approaches, the receptor correlation functions in physical models based on diffusion-influenced reaction is studied. Using analytical and stochastic modeling, this paper focuses on the hybrid regime where diffusion and reaction are not truly separable. The time receptor autocorrelation functions are shown to be indexed by different time scales and their asymptotic expansions are given. Stochastic simulations show that this analysis can be extended to situations with a small number of molecules. It is also demonstrated that this analysis applies when receptor immobilization is coupled to environmental noise.

Strength of interactions between immobilized dye molecules and sol-gel matrices.

PubMed

Ismail, Fanya; Schoenleber, Monika; Mansour, Rolan; Bastani, Behnam; Fielden, Peter; Goddard, Nicholas J

2011-02-21

In this paper we present a new theory to re-examine the immobilization technique of dye doped sol-gel films, define the strength and types of possible bonds between the immobilized molecule and sol-gel glass, and show that the immobilized molecule is not free inside the pores as was previously thought. Immobilizing three different pH sensitive dyes with different size and functional groups inside the same sol-gel films revealed important information about the nature of the interaction between the doped molecule and the sol-gel matrix. The samples were characterized by means of ultraviolet-visible spectrophotometer (UV-VIS), thermal gravimetric analysis (TGA), mercury porosimetry (MP), nuclear magnetic resonance spectroscopy ((29)Si NMR) and field-emission environmental scanning electron microscopy (ESEM-FEG). It was found that the doped molecule itself has a great effect on the strength and types of the bonds. A number of factors were identified, such as number and types of the functional groups, overall charge, size, pK(a) and number of the silanol groups which surround the immobilized molecule. These results were confirmed by the successful immobilization of bromocresol green (BCG) after a completely polymerized sol-gel was made. The sol-gel consisted of 50% tetraethoxysilane (TEOS) and 50% methyltriethoxysilane (MTEOS) (w/w). Moreover, the effect of the immobilized molecule on the structure of the sol-gel was studied by means of a leaky waveguide (LW) mode for doped films made before and after polymerization of the sol-gel.

Covalent immobilization of penicillin G acylase on aminopropyl-functionalized mesostructured cellular foams.

PubMed

Zhao, Junqi; Wang, Yujun; Luo, Guangsheng; Zhu, Shenlin

2010-10-01

Mesostructured cellular foams (MCFs) are suitable for biomolecular immobilization because of their relatively large-pore diameter and pore volume. Penicillin G acylase (PGA) was immobilized on aminopropyl-functionalized MCFs through Schiff base reaction. It is shown that PGA could be fixed more firmly through the covalent immobilization on aminopropyl-functionalized MCFs support than through the adsorption immobilization on blank MCFs. The PGA loading amount on the aminopropyl-functionalized MCFs could reach 443 mg/g (dry support), and the apparent activity could achieve up to 4138 U/g (dry support). The influence of the amount of grafted aminopropyl group was studied, and it is found that the optimal molar ratio of MCFs to APTS was 15/1; in addition, the suitable enzyme distribution density for the specific activity of the immobilized PGA was 0.7 mg enzyme per m(2) of specific area of MCFs. Copyright 2010 Elsevier Ltd. All rights reserved.

Effect of consecutive cooling and immobilization on catecholamine metabolism in rat tissues

NASA Technical Reports Server (NTRS)

Matlina, E. S.; Waysman, S. M.; Zaydner, I. G.; Kogan, B. M.; Nozdracheva, L. V.

1979-01-01

The combined effect of two stressor stimuli--cooling and immobilization--acting successively on the sympathetic-adrenaline system was studied experimentally in rats that were cooled for 8 hours at 7 C on the first day and immobilized for 6 hours on the next day. The biochemical and histochemical methods used and the experimental technique involved are described in detail. The following conclusions were formulated: (1) the successive action of cooling and immobilization results in a stronger decrease in the adrenaline and noradrenaline content in the adrenal gland than that which could be due to a simple summation of the cooling and immobilization effects; (2) successive cooling and immobilization are followed by activation of catecholamine synthesis in the adrenal gland; and (3) 1-DOPA administration (45 mg/kg 3 times in 2 days) intraabdominally activated catecholamine synthesis in the adrenal glands in both the control and test animals.

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

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.

Energy transfer between surface-immobilized light-harvesting chlorophyll a/b complex (LHCII) studied by surface plasmon field-enhanced fluorescence spectroscopy (SPFS).

PubMed

Lauterbach, Rolf; Liu, Jing; Knoll, Wolfgang; Paulsen, Harald

2010-11-16

The major light-harvesting chlorophyll a/b complex (LHCII) of the photosynthetic apparatus in green plants can be viewed as a protein scaffold binding and positioning a large number of pigment molecules that combines rapid and efficient excitation energy transfer with effective protection of its pigments from photobleaching. These properties make LHCII potentially interesting as a light harvester (or a model thereof) in photoelectronic applications. Most of such applications would require the LHCII to be immobilized on a solid surface. In a previous study we showed the immobilization of recombinant LHCII on functionalized gold surfaces via a 6-histidine tag (His tag) in the protein moiety. In this work the occurrence and efficiency of Förster energy transfer between immobilized LHCII on a functionalized surface have been analyzed by surface plasmon field-enhanced fluorescence spectroscopy (SPFS). A near-infrared dye was attached to some but not all of the LHC complexes, serving as an energy acceptor to chlorophylls. Analysis of the energy transfer from chlorophylls to this acceptor dye yielded information about the extent of intercomplex energy transfer between immobilized LHCII.

Novel functionalized fluorescent polymeric nanoparticles for immobilization of biomolecules

NASA Astrophysics Data System (ADS)

Jain, Swati; Chattopadhyay, Sruti; Jackeray, Richa; Abid, C. K. V. Zainul; Singh, Harpal

2013-07-01

Novel, size controlled fluorescent polymeric nanoparticles (FPNP) were synthesized having acetoacetoxy functionality on the surface for immobilization of biomolecules which can be utilized as biomarkers and labels in fluoroimmunoassays. Core-shell nanoparticles of poly(styrene, St-methyl methacrylate, MMA-acetoacetoxy ethyl methacrylate, AAEM), stabilized by various concentrations of surfactant, sodium lauryl sulphate (SLS), were obtained by facile miniemulsion co-polymerization encapsulated with pyrene molecules in their hydrophobic core. Analytical, spectroscopic and imaging characterization techniques revealed the formation of stable, monodisperse, spherical nano sized particles exhibiting high luminescence properties. Particles with 1% SLS (S1) showed good dispersion stability and fluorescence intensity and were chosen as ideal candidates for further immobilization studies. Steady state fluorescence studies showed 10 times higher fluorescence intensity of S1 nanoparticles than that of pyrene solution in solvent-toluene at the same concentration. Environmental factors such as pH, ionic strength and time were found to have no effect on fluorescence intensity of FPNPs. Surface β-di-ketone groups were utilized for the covalent immobilization of enzyme conjugated antibodies without any activation or pre-treatment of nanoparticles.Novel, size controlled fluorescent polymeric nanoparticles (FPNP) were synthesized having acetoacetoxy functionality on the surface for immobilization of biomolecules which can be utilized as biomarkers and labels in fluoroimmunoassays. Core-shell nanoparticles of poly(styrene, St-methyl methacrylate, MMA-acetoacetoxy ethyl methacrylate, AAEM), stabilized by various concentrations of surfactant, sodium lauryl sulphate (SLS), were obtained by facile miniemulsion co-polymerization encapsulated with pyrene molecules in their hydrophobic core. Analytical, spectroscopic and imaging characterization techniques revealed the formation of stable

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.

Biosorption of americium-241 by immobilized Rhizopus arrihizus.

PubMed

Liao, Jiali; Yang, Yuanyou; Luo, Shunzhong; Liu, Ning; Jin, Jiannan; Zhang, Taiming; Zhao, Pengji

2004-01-01

Rhizopus arrihizus (R. arrihizus), a fungus, which in previous experiments had shown encouraging ability to remove 241Am from solutions, was immobilized by calcium alginate and other reagents. The various factors affecting 241Am biosorption by the immobilized R. arrihizus were investigated. The results showed that not only can immobilized R. arrihizus adsorb 241Am as efficiently as free R. arrihizus, but that also can be used repeatedly or continuously. The biosorption equilibrium was achieved within 2 h, and more than 94% of 241Am was removed from 241Am solutions of 1.08 MBq/l by immobilized R. arrihizu in the pH range 1-7. Temperature did not affect the adsorption on immobilized R. arrihizus in the range 15-45 degrees C. After repeated adsorption for 8 times, the immobilized R. arrihizus still adsorbed more than 97% of 241Am. At this time, the total adsorption of 241Am was more than 88.6 KBq/g, and had not yet reached saturation. Ninety-five percent of the adsorbed 241Am was desorbed by saturated EDTA solution and 98% by 2 mol/l HNO(3).

The estimation of quantitative parameters of oligonucleotides immobilization on mica surface

NASA Astrophysics Data System (ADS)

Sharipov, T. I.; Bakhtizin, R. Z.

2017-05-01

Immobilization of nucleic acids on the surface of various materials is increasingly being used in research and some practical applications. Currently, the DNA chip technology is rapidly developing. The basis of the immobilization process can be both physical adsorption and chemisorption. A useful way to control the immobilization of nucleic acids on a surface is to use atomic force microscopy. It allows you to investigate the topography of the surface by its direct imaging with high resolution. Usually, to fix the DNA on the surface of mica are used cations which mediate the interaction between the mica surface and the DNA molecules. In our work we have developed a method for estimation of quantitative parameter of immobilization of oligonucleotides is their degree of aggregation depending on the fixation conditions on the surface of mica. The results on study of aggregation of oligonucleotides immobilized on mica surface will be presented. The single oligonucleotides molecules have been imaged clearly, whereas their surface areas have been calculated and calibration curve has been plotted.

Layer uniformity in glucose oxidase immobilization on SiO 2 surfaces

NASA Astrophysics Data System (ADS)

Libertino, Sebania; Scandurra, Antonino; Aiello, Venera; Giannazzo, Filippo; Sinatra, Fulvia; Renis, Marcella; Fichera, Manuela

2007-09-01

The goal of this work was the characterization, step by step, of the enzyme glucose oxidase (GOx) immobilization on silicon oxide surfaces, mainly by means of X-Ray photoelectron spectroscopy (XPS). The immobilization protocol consists of four steps: oxide activation, silanization, linker molecule deposition and GOx immobilization. The linker molecule, glutaraldehyde (GA) in this study, must be able to form a uniform layer on the sample surface in order to maximize the sites available for enzyme bonding and achieve the best enzyme deposition. Using a thin SiO 2 layer grown on Si wafers and following the XPS Si2p signal of the Si substrate during the immobilization steps, we demonstrated both the glutaraldehyde layer uniformity and the possibility to use XPS to monitor thin layer uniformity. In fact, the XPS substrate signal, not shielded by the oxide, is suppressed only when a uniform layer is deposited. The enzyme correct immobilization was monitored using the XPS C1s and N1s signals. Atomic force microscopy (AFM) measurements carried out on the same samples confirmed the results.

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.

Rapid detection of food pathogens using RNA aptamers-immobilized slide.

PubMed

Maeng, Jin-Soo; Kim, Namsoo; Kim, Chong-Tai; Han, Seung Ryul; Lee, Young Ju; Lee, Seong-Wook; Lee, Myung-Hyun; Cho, Yong-Jin

2012-07-01

The purpose of this study was to develop a simple and rapid detection system for foodborne bacteria, which consisted of an optical microscope and its slide chip with artificial antibodies, or RNA aptamers. From an RNA pool, three each RNA aptamers were built by the method of SELEX (systematic evolution of ligands by exponential enrichment) for components of cell wall, LPS (lipopolysaccharide) from E. coli O157:H7, teichoic acid from Staphylococcus aureus and a cell membrane protein of OmpC from Salmonella typhimurium, respectively. These aptamers were hybridized with thiol-conjugated 16 dT-linker molecules in order to be immobilized on silver surface which was, in advance, fabricated on glass slide, using a spin-coating method. To confirm that each aptamers retained its specific binding activities to their antigenic live bacteria, microscopic view of bound cells immobilized on silver film were observed. Furthermore, we observed the fluorescence-emitting bacteria-aptamer complex immobilized on silver film after adding RNA aptamers hybridized with fluorophore, FAM-conjugated 16 dT-linker molecules. As a result, the RNA aptamers-immobilized slide system developed in this study was a useful new tool to rapidly monitor individual food pathogens.

Immobilization of Streptomyces thermotolerans 11432 on polyurethane foam to improve production of acetylisovaleryltylosin.

PubMed

Zhu, Hongji; Wang, Weihua; Liu, Jiaheng; Caiyin, Qinggele; Qiao, Jianjun

2015-01-01

In this study, polyurethane foam (PUF) was chemically treated to immobilize Streptomyces thermotolerans 11432 for semi-continuous production of acetylisovaleryltylosin (AIV). Based on experimental results, positive cross-linked PUF (PCPUF) was selected as the most effective carrier according to immobilized cell mass. The effect of adsorption time on immobilized mass was investigated. AIV concentration (33.54 mg/l) in batch fermentations with immobilized cells was higher than with free cells (20.34 mg/l). In repeated batch fermentations with immobilized S. thermotolerans 11432 using PCPUF cubes, high AIV concentrations and conversion rates were attained, ranging from 25.56 to 34.37 mg/l and 79.93 to 86.31 %, respectively. Significantly, this method provides a feasible strategy for efficient AIV production and offers the potential for large-scale production.

Enzyme Engineering for In Situ Immobilization.

PubMed

Rehm, Fabian B H; Chen, Shuxiong; Rehm, Bernd H A

2016-10-14

Enzymes are used as biocatalysts in a vast range of industrial applications. Immobilization of enzymes to solid supports or their self-assembly into insoluble particles enhances their applicability by strongly improving properties such as stability in changing environments, re-usability and applicability in continuous biocatalytic processes. The possibility of co-immobilizing various functionally related enzymes involved in multistep synthesis, conversion or degradation reactions enables the design of multifunctional biocatalyst with enhanced performance compared to their soluble counterparts. This review provides a brief overview of up-to-date in vitro immobilization strategies while focusing on recent advances in enzyme engineering towards in situ self-assembly into insoluble particles. In situ self-assembly approaches include the bioengineering of bacteria to abundantly form enzymatically active inclusion bodies such as enzyme inclusions or enzyme-coated polyhydroxyalkanoate granules. These one-step production strategies for immobilized enzymes avoid prefabrication of the carrier as well as chemical cross-linking or attachment to a support material while the controlled oriented display strongly enhances the fraction of accessible catalytic sites and hence functional enzymes.

Biodegradation of different petroleum hydrocarbons by free and immobilized microbial consortia.

PubMed

Shen, Tiantian; Pi, Yongrui; Bao, Mutai; Xu, Nana; Li, Yiming; Lu, Jinren

2015-12-01

The efficiencies of free and immobilized microbial consortia in the degradation of different types of petroleum hydrocarbons were investigated. In this study, the biodegradation rates of naphthalene, phenanthrene, pyrene and crude oil reached about 80%, 30%, 56% and 48% under the optimum environmental conditions of free microbial consortia after 7 d. We evaluated five unique co-metabolic substances with petroleum hydrocarbons, α-lactose was the best co-metabolic substance among glucose, α-lactose, soluble starch, yeast powder and urea. The orthogonal biodegradation analysis results showed that semi-coke was the best immobilized carrier followed by walnut shell and activated carbon. Meanwhile, the significance of various factors that contribute to the biodegradation of semi-coke immobilized microbial consortia followed the order of: α-lactose > semi-coke > sodium alginate > CaCl2. Moreover, the degradation rate of the immobilized microbial consortium (47%) was higher than that of a free microbial consortium (26%) under environmental conditions such as the crude oil concentration of 3 g L(-1), NaCl concentration of 20 g L(-1), pH at 7.2-7.4 and temperature of 25 °C after 5 d. SEM and FTIR analyses revealed that the structure of semi-coke became more porous and easily adhered to the microbial consortium; the functional groups (e.g., hydroxy and phosphate) were identified in the microbial consortium and were changed by immobilization. This study demonstrated that the ability of microbial adaptation to the environment can be improved by immobilization which expands the application fields of microbial remediation.

Geometry-dependent DNA-TiO2 immobilization mechanism: A spectroscopic approach

NASA Astrophysics Data System (ADS)

Silva-Moraes, M. O.; Garcia-Basabe, Y.; de Souza, R. F. B.; Mota, A. J.; Passos, R. R.; Galante, D.; Fonseca Filho, H. D.; Romaguera-Barcelay, Y.; Rocco, M. L. M.; Brito, W. R.

2018-06-01

DNA nucleotides are used as a molecular recognition system on electrodes modified to be applied in the detection of various diseases, but immobilization mechanisms, as well as, charge transfers are not satisfactorily described in the literature. An electrochemical and spectroscopic study was carried out to characterize the molecular groups involved in the direct immobilization of DNA structures on the surface of nanostructured TiO2 with the aim of evaluating the influence of the geometrical aspects. X-ray photoelectron spectroscopy at O1s and P2p core levels indicate that immobilization of DNA samples occurs through covalent (Psbnd Osbnd Ti) bonds. X-ray absorption spectra at the Ti2p edge reinforce this conclusion. A new species at 138.5 eV was reported from P2p XPS spectra analysis which plays an important role in DNA-TiO2 immobilization. The Psbnd Osbnd Ti/Osbnd Ti ratio showed that quantitatively the DNA immobilization mechanism is dependent on their geometry, becoming more efficient for plasmid ds-DNA structures than for PCR ds-DNA structures. The analysis of photoabsorption spectra at C1s edge revealed that the molecular groups that participate in the C1s → LUMO electronic transitions have different pathways in the charge transfer processes at the DNA-TiO2 interface. Our results may contribute to additional studies of immobilization mechanisms understanding the influence of the geometry of different DNA molecules on nanostructured semiconductor and possible impact to the charge transfer processes with application in biosensors or aptamers.

Biosorption of trivalent chromium by free and immobilized blue green algae: kinetics and equilibrium studies.

PubMed

Shashirekha, V; Sridharan, M R; Swamy, Mahadeswara

2008-03-01

The process of biosorption of trivalent chromium (Cr(3+)) by live culture of Spirulina platensis and the sorption potential by the dried biomass, in both free and immobilized states have been investigated for a simulated chrome liquor in the concentration range of 100-4500 ppm. Both live and dried biomass were very good biosorbents as they could remove high amounts of chromium from tannery wastewater. Polyurethane foam and sodium alginate were used as immobilizing agents and their performances compared. Biosorption kinetic data on Cr(3+) sorption onto dried biomass were analyzed using pseudo-first-and pseudo-second-order kinetic models in batch column experiments. The second-order equation was more appropriate to predict the rate of biosorption. Subsequently, the effects of height of packing & diameter of the column, concentration of blue-green algae (BGA) in varying amounts of sodium alginate, chromium concentration were studied. The results fit into both Langmuir & Freundlich isotherm models with very high regression coefficients. Furthermore, equilibrium studies using retan chrome liquor (RCL), with a chromium concentration of 1660 ppm, obtained from a tannery also showed promising results. In general, our studies indicate the efficacy of the algal species in removal of chromium from tannery wastewater.

Cognitive representations of AIDS: a phenomenological study.

PubMed

Anderson, Elizabeth H; Spencer, Margaret Hull

2002-12-01

Cognitive representations of illness determine behavior. How persons living with AIDS image their disease might be key to understanding medication adherence and other health behaviors. The authors' purpose was to describe AIDS patients' cognitive representations of their illness. A purposive sample of 58 men and women with AIDS were interviewed. Using Colaizzi's (1978) phenomenological method, rigor was established through application of verification, validation, and validity. From 175 significant statements, 11 themes emerged. Cognitive representations included imaging AIDS as death, bodily destruction, and just a disease. Coping focused on wiping AIDS out of the mind, hoping for the right drug, and caring for oneself. Inquiring about a patient's image of AIDS might help nurses assess coping processes and enhance nurse-patient relationships.

Ethanol production using immobilized Saccharomyces cerevisiae in lyophilized cellulose gel.

PubMed

Winkelhausen, Eleonora; Velickova, Elena; Amartey, Samuel A; Kuzmanova, Slobodanka

2010-12-01

A new lyophilization technique was used for immobilization of Saccharomyces cerevisiae cells in hydroxyethylcellulose (HEC) gels. The suitability of the lyophilized HEC gels to serve as immobilization matrices for the yeast cells was assessed by calculating the immobilization efficiency and the cell retention in three consecutive batches, each in duration of 72 h. Throughout the repeated batch fermentation, the immobilization efficiency was almost constant with an average value of 0.92 (12-216 h). The maximum value of cell retention was 0.24 g immobilized cells/g gel. Both parameters indicated that lyophilized gels are stable and capable of retaining the immobilized yeast cells. Showing the yeast cells propagation within the polymeric matrix, the scanning electron microscope images also confirmed that the lyophilization technique for immobilization of S. cerevisiae cells in the HEC gels was successful. The activity of the immobilized yeast cells was demonstrated by their capacity to convert glucose to ethanol. Ethanol yield of 0.40, 0.43 and 0.30 g ethanol/g glucose corresponding to 79%, 84% and 60% of the theoretical yield was attained in the first, second and third batches, respectively. The cell leakage was less than 10% of the average concentration of the immobilized cells.

Histological and compositional responses of bone to immobilization and other experimental conditions

NASA Technical Reports Server (NTRS)

Brown, R. J.; Niklowitz, W. J.

1985-01-01

Histological techniques were utilized for evaluating progressive changes in tibial compact bone in adult male monkeys during chronic studies of immobilization-associated osteopenia. The animals were restrained in a semirecumbent position which reduces normally occurring stresses in the lower extremities and results in bone mass loss. The longest immobilization studies were of seven months duration. Losses of haversian bone tended to occur predominatly in the proximal tibia and were characterized by increased activation with excessive depth of penetration of osteoclastic activity. There was no apparent regulation of the size and orientation of resorption cavities. Rapid bone loss seen during 10 weeks of immobilization appeared to be due to unrestrained osteoclastic activity without controls and regulation which are characteristic of adaptive systems. The general pattern of loss persisted throughout 7 months of immobilization. Clear cut evidence of a formation phase in haversian bone was seen only after two months of reambulation.

Effect of kinesthetic illusion induced by visual stimulation on muscular output function after short-term immobilization.

PubMed

Inada, Toru; Kaneko, Fuminari; Hayami, Tatsuya

2016-04-01

Kinesthetic illusions by visual stimulation (KiNVIS) enhances corticomotor excitability and activates motor association areas. The purpose of this study was to investigate the effect of KiNVIS induction on muscular output function after short-term immobilization. Thirty subjects were assigned to 3 groups: an immobilization group, with the left hand immobilized for 12h (immobilization period); an illusion group, with the left hand immobilized and additionally subjected to KiNVIS of the immobilized part during the immobilization period; and a control group with no manipulation. The maximum voluntary contraction (MVC), fluctuation of force (force fluctuation) during a force modulation task, and twitch force were measured both before (pre-test) and after (post-test) the immobilization period. Data were analyzed by performing two-way (TIME×GROUP) repeated measures ANOVA. The MVC decreased in the immobilization group only (pre-test; 37.8±6.1N, post-test; 32.8±6.9N, p<0.0005) after the immobilization period. The force fluctuation increased only in the immobilization group (pre-test; 2.19±0.54%, post-test; 2.78±0.87%, p=0.007) after the immobilization period. These results demonstrate that induction of KiNVIS prevents negative effect on MVC and force fluctuation after 12h of immobilization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of two educational method of lecturing and role playing on knowledge and performance of high school students in first aid at emergency scene

PubMed Central

Hassanzadeh, Akbar; Vasili, Arezu; Zare, Zahra

2010-01-01

BACKGROUND: This study aimed to investigate the effects of two educational methods on students' knowledge and performance regarding first aid at emergency scenes. METHODS: In this semi-experimental study, the sample was selected randomly among male and female public high school students of Isfahan. Each group included 60 students. At first the knowledge and performance of students in first aid at emergency scene was assessed using a researcher-made questionnaire. Then necessary education was provided to the students within 10 sessions of two hours by lecturing and role playing. The students' knowledge and performance was as-sessed again and the results were compared. RESULTS: It was no significant relationship between the frequency distribution of students' age, major and knowledge and performance before the educational course in the two groups. The score of knowledge in performing CPR, using proper way to bandage, immobilizing the injured area, and proper ways of carrying injured person after the education was significantly increased in both groups. Moreover, the performance in proper way to bandage, immobilizing injured area and proper ways of carrying injured person after educational course was significantly higher in playing role group compared to lecturing group after education. CONCLUSIONS: Iran is a developing country with a young generation and it is a country with high risk of natural disasters; so, providing necessary education with more effective methods can be effective in reducing mortality and morbidity due to lack of first aid care in crucial moments. Training with playing role is suggested for this purpose. PMID:21589743

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.

Aroma formation by immobilized yeast cells in fermentation processes.

PubMed

Nedović, V; Gibson, B; Mantzouridou, T F; Bugarski, B; Djordjević, V; Kalušević, A; Paraskevopoulou, A; Sandell, M; Šmogrovičová, D; Yilmaztekin, M

2015-01-01

Immobilized cell technology has shown a significant promotional effect on the fermentation of alcoholic beverages such as beer, wine and cider. However, genetic, morphological and physiological alterations occurring in immobilized yeast cells impact on aroma formation during fermentation processes. The focus of this review is exploitation of existing knowledge on the biochemistry and the biological role of flavour production in yeast for the biotechnological production of aroma compounds of industrial importance, by means of immobilized yeast. Various types of carrier materials and immobilization methods proposed for application in beer, wine, fruit wine, cider and mead production are presented. Engineering aspects with special emphasis on immobilized cell bioreactor design, operation and scale-up potential are also discussed. Ultimately, examples of products with improved quality properties within the alcoholic beverages are addressed, together with identification and description of the future perspectives and scope for cell immobilization in fermentation processes. Copyright © 2014 John Wiley & Sons, Ltd.

Polymer-Immobilized Photosensitizers for Continuous Eradication of Bacteria

PubMed Central

Valkov, Anton; Nakonechny, Faina; Nisnevitch, Marina

2014-01-01

The photosensitizers Rose Bengal (RB) and methylene blue (MB), when immobilized in polystyrene, were found to exhibit high antibacterial activity in a continuous regime. The photosensitizers were immobilized by dissolution in chloroform, together with polystyrene, with further evaporation of the solvent, yielding thin polymeric films. Shallow reservoirs, bottom-covered with these films, were used for constructing continuous-flow photoreactors for the eradication of Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli and wastewater bacteria under illumination with visible white light using a luminescent lamp at a 1.8 mW·cm−2 fluence rate. The bacterial concentration decreased by two to five orders of magnitude in separate reactors with either immobilized RB or MB, as well as in three reactors connected in series, which contained one of the photosensitizers. Bacterial eradication reached more than five orders of magnitude in two reactors connected in series, where the first reactor contained immobilized RB and the second contained immobilized MB. PMID:25158236

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.).

A new model of skeletal muscle atrophy induced by immobilization using a hook-and-loop fastener in mice

PubMed Central

Aihara, Masahiro; Hirose, Noboru; Katsuta, Wakana; Saito, Fumiaki; Maruyama, Hitoshi; Hagiwara, Hiroki

2017-01-01

[Purpose] To study muscle atrophy, the muscle atrophy model mice have been used frequently. In particular, cast immobilization is the most common method to induce muscle atrophy. However, it is time consuming and often causes adverse events including skin injury, edema, and necrosis. The present study, we developed a hook-and-loop fastener (Velcro) immobilization method as a new, simple, and less invasive approach to induce muscle atrophy. [Subjects and Methods] Mice were bandaged in the knee joint extension and ankle plantar extension position. Muscle atrophy was induced by either winding a cast or Velcro around the limb. [Results] According to weight and fiber size, Velcro immobilization induced equivalent muscle atrophy to cast immobilization. Velcro immobilization reduced significantly the time for the procedure and the frequency of adverse events. [Conclusion] Velcro immobilization can induce muscle atrophy comparable to cast immobilization, but in a shorter time and with less complications. Velcro immobilization may contribute to the study of disuse muscle atrophy in clinical practice of physical therapy using a mouse model. PMID:29184288

Stereospecificity of mushroom tyrosinase immobilized on a chiral and a nonchiral support.

PubMed

Marín-Zamora, María Elisa; Rojas-Melgarejo, Francisco; García-Canovas, Francisco; García-Ruiz, Pedro Antonio

2007-05-30

Mushroom tyrosinase was immobilized from an extract onto glass beads covered with the cross-linked totally cinnamoylated derivates of d-sorbitol (sorbitol cinnamate) and glycerine (glycerine cinnamate). The enzyme was immobilized onto the support by direct adsorption, and the quantity of immobilized tyrosinase was higher for sorbitol cinnamate, the support with the higher number of esterified hydroxyls per unit of monosacharide, than for glycerine cinnamate. The results obtained from the stereospecificity study of the monophenolase and diphenolase activity of immobilized mushroom tyrosinase are reported. The enantiomers L-tyrosine, DL-tyrosine, D-tyrosine, L-dopa, DL-dopa, D-dopa, L-alpha-methyldopa, DL-alpha-methyldopa, L-isoprenaline, DL-isoprenaline, L-adrenaline, DL-adrenaline, L-noradrenaline, and D-noradrenaline were assayed with tyrosinase immobilized on a chiral support (sorbitol cinnamate), whereas L-tyrosine, DL-tyrosine, D-tyrosine, L-dopa, DL-dopa, D-dopa, L-alpha-methyldopa, and DL-alpha-methyldopa were assayed with tyrosinase immobilized on a nonchiral support (glycerine cinnamate). The same Vmax(app) values for each series of enantiomers were obtained. However, the Km(app) values were different, the l isomers showing lower values than the dl isomers, whereas the highest Km(app) value was obtained with d isomers. No difference was observed in the stereospecificity of tyrosinase immobilized on a chiral (sorbitol cinnamate) or nonchiral (glycerine cinnamate) support.

Change in blood glucose level in rats after immobilization

NASA Technical Reports Server (NTRS)

Platonov, R. D.; Baskakova, G. M.; Chepurnov, S. A.

1981-01-01

Experiments were carried out on male white rats divided into four groups. In group one the blood glucose level was determined immediately after immobilization. In the other three groups, two hours following immobilization, the blood glucose level was determined every 20 minutes for 3 hours 40 minutes by the glucose oxidase method. Preliminary immobilization for 2 hours removed the increase in the blood glucose caused by the stress reaction. By the 2nd hour of immobilization in the presence of continuing stress, the blood glucose level stabilized and varied within 42 + or - 5.5 and 47 + or - 8.1 mg %. Within 2 hours after the immobilization, the differences in the blood glucose level of the rats from the control groups were statistically insignificant.

EPS production by Propionibacterium freudenreichii facilitates its immobilization for propionic acid production.

PubMed

Belgrano, F D S; Verçoza, B R F; Rodrigues, J C F; Hatti-Kaul, R; Pereira, N

2018-04-28

Immobilization of microbial cells is a useful strategy for developing high cell density bioreactors with improved stability and productivity for production of different chemicals. Functionalization of the immobilization matrix or biofilm forming property of some strains has been utilized for achieving cell attachment. The aim of the present study was to investigate the production of exopolysaccharide (EPS) by Propionibacterium freudenreichii C.I.P 59.32 and utilize this feature for immobilization of the cells on porous glass beads for production of propionic acid. Propionibacterium freudenreichii was shown to produce both capsular and excreted EPS during batch cultivations using glucose as carbon source. Different electron microscopy techniques confirmed the secretion of EPS and formation of cellular aggregates. The excreted EPS was mainly composed of mannose and glucose in a 5·3 : 1 g g -1 ratio. Immobilization of the cells on untreated and polyethyleneimine (PEI)-treated Poraver beads in a bioreactor was evaluated. Higher productivity and yield of propionic acid (0·566 g l -1  h -1 and 0·314 g g -1 , respectively) was achieved using cells immobilized to untreated beads and EPS production reached 617·5 mg l -1 after 48 h. These results suggest an important role of EPS-producing strains for improving cell immobilization and propionic acid production. This study demonstrates the EPS-producing microbe to be easily immobilized on a solid matrix and to be used in a bioprocess. Such a system could be optimized for achieving high cell density in fermentations without the need for functionalization of the matrix. © 2018 The Society for Applied Microbiology.

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.

Limited proteolysis in proteomics using protease-immobilized microreactors.

PubMed

Yamaguchi, Hiroshi; Miyazaki, Masaya; Maeda, Hideaki

2012-01-01

Proteolysis is the key step for proteomic studies integrated with MS analysis. Compared with the conventional method of in-solution digestion, proteolysis by a protease-immobilized microreactor has a number of advantages for proteomic analysis; i.e., rapid and efficient digestion, elimination of a purification step of the digests prior to MS, and high stability against a chemical or thermal denaturant. This chapter describes the preparation of the protease-immobilized microreactors and proteolysis performance of these microreactors. Immobilization of proteases by the formation of a polymeric membrane consisting solely of protease-proteins on the inner wall of the microchannel is performed. This was realized either by a cross-linking reaction in a laminar flow between lysine residues sufficiently present on the protein surfaces themselves or in the case of acidic proteins by mixing them with poly-lysine prior to the crosslink-reaction. The present procedure is simple and widely useful not only for proteases but also for several other enzymes.

Plasma lactate concentrations in free-ranging moose (Alces alces) immobilized with etorphine.

PubMed

Haga, Henning A; Wenger, Sandra; Hvarnes, Silje; Os, Oystein; Rolandsen, Christer M; Solberg, Erling J

2009-11-01

To investigate plasma lactate concentrations of etorphine-immobilized moose in relation to environmental, temporal and physiological parameters. Prospective clinical study. Fourteen female and five male moose (Alces alces), estimated age range 1-7 years. The moose were darted from a helicopter with 7.5 mg etorphine per animal using projectile syringes and a dart gun. Once immobilized, the moose were approached, a venous blood sample was obtained and vital signs including pulse oximetry were recorded. Diprenorphine was administered to reverse the effects of etorphine. Timing of events, ambient temperature and snow depth were recorded. Blood samples were cooled and centrifuged before plasma was harvested and frozen. The plasma was thawed later and lactate analysed. Data were analysed using descriptive statistics and regression analysis. All animals recovered uneventfully and were alive 12 weeks after immobilization. Mean +/- SD plasma lactate was found to be 9.2 +/- 2.1 mmol L(-1). Plasma lactate concentrations were related positively to snow depth and negatively to time from induction of immobilization to blood sampling. The model that best described the variability in plasma lactate concentrations used induction time (time from firing the dart to the moose being immobilized). The second best model included induction time and snow depth. Plasma lactate concentrations in these etorphine-immobilized moose were in the range reported for other immobilized wild ruminants. Decreasing induction time, which may be related to a more profound etorphine effect, and increasing snow depth possibly may increase plasma lactate concentrations in etorphine-immobilized moose.

Purification-Free, Target-Selective Immobilization of a Protein from Cell Lysates.

PubMed

Cha, Jaehyun; Kwon, Inchan

2018-02-27

Protein immobilization has been widely used for laboratory experiments and industrial processes. Preparation of a recombinant protein for immobilization usually requires laborious and expensive purification steps. Here, a novel purification-free, target-selective immobilization technique of a protein from cell lysates is reported. Purification steps are skipped by immobilizing a target protein containing a clickable non-natural amino acid (p-azidophenylalanine) in cell lysates onto alkyne-functionalized solid supports via bioorthogonal azide-alkyne cycloaddition. In order to achieve a target protein-selective immobilization, p-azidophenylalanine was introduced into an exogenous target protein, but not into endogenous non-target proteins using host cells with amber codon-free genomic DNAs. Immobilization of superfolder fluorescent protein (sfGFP) from cell lysates is as efficient as that of the purified sfGFP. Using two fluorescent proteins (sfGFP and mCherry), the authors also demonstrated that the target proteins are immobilized with a minimal immobilization of non-target proteins (target-selective immobilization). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of Immobilized Biomolecules on Magnetic Bead Plug Formation and Retention in Capillary Electrophoresis

PubMed Central

Henken, Rachel L.; Chantiwas, Rattikan; Gilman, S. Douglass

2012-01-01

Significant changes in the formation and retention of magnetic bead plugs in a capillary during electrophoresis were studied, and it was demonstrated that these effects were due to the type of biological molecule immobilized on the surface of these beads. Three biological molecules, an antibody, an oligonucleotide and alkaline phosphatase, were attached to otherwise identical streptavidin-coated magnetic beads through biotin-avidin binding in order to isolate differences in bead immobilization in a magnetic field resulting from the type of biological molecule immobilized on the bead surface. Alkaline phosphatase also was attached to the magnetic beads using epoxy groups on the bead surfaces (instead of avidin-biotin binding) to study the impact of immobilization chemistry. The formation and retention of magnetic bead plugs were studied quantitatively using light scattering detection of magnetic particles eluting from the bead plugs and qualitatively using microscopy. Both the type of biomolecule immobilized on the magnetic bead surface and the chemistry used to link the biomolecule to the magnetic bead impacted the formation and retention of the bead plugs. PMID:22437880

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.

Study of immobilized and extracellular saccharase of watermelon.

PubMed

Stano, Ján; Siekel, Peter; Micieta, Karol; Barth, Alfred

2006-01-01

A simple, rapid and reproducible procedure for the identification and determination of extracellular saccharase from culture medium of watermelon cell suspension cultures is described. The culture medium (without cells) was used for the identification and determination of extracellular enzyme activity. Intracellular activity was estimated from the cell suspension. Watermelon cell suspension was permeabilized by Tween 80 and immobilized by glutaraldehyde. The highest saccharase activity was at pH 4.6 at a temperature of 50 degrees C. The hydrolysis of substrate was linear 5h after reaching 60% conversion. The cells had high saccharase activity and good stability, and in long-term storage they showed convenient physico-mechanical properties.

Activation of immobilized enzymes by acoustic wave resonance oscillation.

PubMed

Nishiyama, Hiroshi; Watanabe, Tomoya; Inoue, Yasunobu

2014-12-01

Acoustic wave resonance oscillation has been used successfully in the development of methods to activate immobilized enzyme catalysts. In this study, resonance oscillation effects were demonstrated for enzyme reactions on galactose oxidase (GAD), D-amino acid oxidase (DAAO), and L-amino acid oxidase (LAAO), all of which were immobilized covalently on a ferroelectric lead zirconate titanate (PZT) device that could generate thickness-extensional resonance oscillations (TERO) of acoustic waves. For galactose oxidation on immobilized GAD in a microreactor, TERO generation immediately increased enzyme activity 2- to 3-fold. Eliminating TERO caused a slight decrease in the activity, with ∼90% of the enhanced activity retained while the reaction proceeded. Contact of the enhanced enzyme with a galactose-free solution caused almost complete reversion of the activity to the original low level before TERO generation, indicating that, not only TERO-induced GAD activation, but also preservation of the increased activity, required a galactose substrate. Similar activity changes with TERO were observed for enzyme reactions on DAAO and LAAO. Kinetic analysis demonstrated that TERO helped strengthen the interactions of the immobilized enzyme with the reactant substrate and promoted formation of an activation complex. Copyright © 2014 Elsevier Inc. All rights reserved.

Immobilization of α-amylase onto a calix[4]arene derivative: Evaluation of its enzymatic activity.

PubMed

Veesar, Irshad Ali; Solangi, Imam Bakhsh; Memon, Shahabuddin

2015-06-01

In order to enhance the cost-effectiveness practicability of enzymes in many industries such as pharmaceutical, food, medical and some other technological processes, there is great need to immobilize them onto a solid supports. In this study, a new and efficient immobilization of α-amylase from Saccharomyces cerevisiae has been developed by using the surface functionalization of calix[4]arene as support. A glutaraldehyde-containing amino group functionalized calix[4]arene was used to immobilize α-amylase covalently. In this procedure, imide bonds are formed between amino groups on the protein and aldehyde groups on the calix[4]arene surface. The surface modified support was characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM). The effect of various preparation conditions on the immobilized α-amylase process such as immobilization time, enzyme concentration, temperature and pH were investigated. The influence of pH and temperature on the activity of free and immobilized α-amylase was also studied using starch as substrate. The optimum reaction temperature and pH value for the enzymatic conversion catalyzed by the immobilized α-amylase were 25°C and 7, respectively. Compared to the free enzyme, the immobilized α-amylase retained 85% of its original activity and exhibited significant thermal stability than the free one and excellent durability. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of membranes with various hydrophobic/hydrophilic properties on lipase immobilized activity and stability.

PubMed

Chen, Guan-Jie; Kuo, Chia-Hung; Chen, Chih-I; Yu, Chung-Cheng; Shieh, Chwen-Jen; Liu, Yung-Chuan

2012-02-01

In this study, three membranes: regenerated cellulose (RC), glass fiber (GF) and polyvinylidene fluoride (PVDF), were grafted with 1,4-diaminobutane (DA) and activated with glutaraldehyde (GA) for lipase covalent immobilization. The efficiencies of lipases immobilized on these membranes with different hydrophobic/hydrophilic properties were compared. The lipase immobilized on hydrophobic PVDF-DA-GA membrane exhibited more than an 11-fold increase in activity compared to its immobilization on a hydrophilic RC-DA-GA membrane. The relationship between surface hydrophobicity and immobilized efficiencies was investigated using hydrophobic/hydrophilic GF membranes which were prepared by grafting a different ratio of n-butylamine/1,4-diaminobutane (BA/DA). The immobilized lipase activity on the GF membrane increased with the increased BA/DA ratio. This means that lipase activity was exhibited more on the hydrophobic surface. Moreover, the modified PVDF-DA membrane was grafted with GA, epichlorohydrin (EPI) and cyanuric chloride (CC), respectively. The lipase immobilized on the PVDF-DA-EPI membrane displayed the highest specific activity compared to other membranes. This immobilized lipase exhibited more significant stability on pH, thermal, reuse, and storage than did the free enzyme. The results exhibited that the EPI modified PVDF is a promising support for lipase immobilization. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

A simple and robust approach to immobilization of antibody fragments.

PubMed

Ikonomova, Svetlana P; He, Ziming; Karlsson, Amy J

2016-08-01

Antibody fragments, such as the single-chain variable fragment (scFv), have much potential in research and diagnostics because of their antigen-binding ability similar to a full-sized antibody and their ease of production in microorganisms. Some applications of antibody fragments require immobilization on a surface, and we have established a simple immobilization method that is based on the biotin-streptavidin interaction and does not require a separate purification step. We genetically fused two biotinylation tags-the biotin carboxyl carrier protein (BCCP) or the AviTag minimal sequence-to six different scFvs (scFv13R4, scFvD10, scFv26-10, scFv3, scFv5, and scFv12) for site-specific biotinylation in vivo by endogenous biotin ligases produced by Escherichia coli. The biotinylated scFvs were immobilized onto streptavidin-coated plates directly from cell lysates, and immobilization was detected through enzyme-linked immunosorbent assays. All scFvs fusions were successfully immobilized, and scFvs biotinylated via the BCCP tag tended to immobilize better than those biotinylated via the AviTag, even when biotinylation efficiency was improved with the biotin ligase BirA. The ability of immobilized scFvs to bind antigens was confirmed using scFv13R4 and scFvD10 with their respective targets β-galactosidase and bacteriophage lambda head protein D (gpD). The immobilized scFv13R4 bound to β-galactosidase at the same level for both biotinylation tags when the surface was saturated with the scFv, and immobilized scFvs retained their functionality for at least 100days after immobilization. The simplicity and robustness of our method make it a promising approach for future applications that require antibody fragment immobilization. Copyright © 2016 Elsevier B.V. All rights reserved.

Candidacy for Bilateral Hearing Aids: A Retrospective Multicenter Study

ERIC Educational Resources Information Center

Boymans, Monique; Goverts, S. Theo; Kramer, Sophia E.; Festen, Joost M.; Dreschler, Wouter A.

2009-01-01

Purpose: The goal of this study was to find factors for refining candidacy criteria for bilateral hearing aid fittings. Clinical files of 1,000 consecutive hearing aid fittings were analyzed. Method: Case history, audiometric, and rehabilitation data were collected from clinical files, and an extensive questionnaire on long-term outcome measures…

Immobilization of Fast Reactor First Cycle Raffinate

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

Langley, K. F.; Partridge, B. A.; Wise, M.

This paper describes the results of work to bring forward the timing for the immobilization of first cycle raffinate from reprocessing fuel from the Dounreay Prototype Fast Reactor (PFR). First cycle raffinate is the liquor which contains > 99% of the fission products separated from spent fuel during reprocessing. Approximately 203 m3 of raffinate from the reprocessing of PFR fuel is held in four tanks at the UKAEA's site at Dounreay, Scotland. Two methods of immobilization of this high level waste (HLW) have been considered: vitrification and cementation. Vitrification is the standard industry practice for the immobilization of first cyclemore » raffinate, and many papers have been presented on this technique elsewhere. However, cementation is potentially feasible for immobilizing first cycle raffinate because the heat output is an order of magnitude lower than typical HLW from commercial reprocessing operations such as that at the Sellafield site in Cumbria, England. In fact, it falls within the upper end of the UK definition of intermediate level waste (ILW). Although the decision on which immobilization technique will be employed has yet to be made, initial development work has been undertaken to identify a suitable cementation formulation using inactive simulant of the raffinate. An approach has been made to the waste disposal company Nirex to consider the disposability of the cemented product material. The paper concentrates on the process development work that is being undertaken on cementation to inform the decision making process for selection of the immobilization method.« less

Effect of protein load on stability of immobilized enzymes.

PubMed

Fernandez-Lopez, Laura; Pedrero, Sara G; Lopez-Carrobles, Nerea; Gorines, Beatriz C; Virgen-Ortíz, Jose J; Fernandez-Lafuente, Roberto

2017-03-01

Different lipases have been immobilized on octyl agarose beads at 1mg/g and at maximum loading, via physical interfacial activation versus the octyl layer on the support. The stability of the preparations was analyzed. Most biocatalysts had the expected result: the apparent stability increased using the highly loaded preparations, due to the diffusional limitations that reduced the initial observed activity. However, lipase B from Candida antarctica (CALB) was significantly more stable using the lowly loaded preparation than the maximum loaded one. This negative effect of the enzyme crowding on enzyme stability was found in inactivations at pH 5, 7 or 9, but not in inactivations in the presence of organic solvents. The immobilization using ethanol to reduce the immobilization rate had no effect on the stability of the lowly loaded preparation, while the highly loaded enzyme biocatalysts increased their stabilities, becoming very similar to that of the lowly loaded preparation. Results suggested that CALB molecules immobilized on octyl agarose may be closely packed together due to the high immobilization rate and this produced some negative interactions between immobilized enzyme molecules during enzyme thermal inactivation. Slowing-down the immobilization rate may be a solution for this unexpected problem. Copyright © 2016 Elsevier Inc. All rights reserved.

The removal of thermo-tolerant coliform bacteria by immobilized waste stabilization pond algae.

PubMed

Pearson, H W; Marcon, A E; Melo, H N

2011-01-01

This study investigated the potential of laboratory- scale columns of immobilized micro-algae to disinfect effluents using thermo-tolerant coliforms (TTC) as a model system. Cells of a Chlorella species isolated from a waste stabilization pond complex in Northeast Brazil were immobilized in calcium alginate, packed into glass columns and incubated in contact with TTC suspensions for up to 24 hours. Five to six log removals of TTC were achieved in 6 hours and 11 log removals in 12 hours contact time. The results were similar under artificial light and shaded sunlight. However little or no TTC removal occurred in the light in columns of alginate beads without immobilized algae present or when the immobilized algae were incubated in the dark suggesting that the presence of both algae and light were necessary for TTC decay. There was a positive correlation between K(b) values for TTC and increasing pH in the effluent from the immobilized algal columns within the range pH 7.2 and 8.9. The potential of immobilized algal technology for wastewater disinfection may warrant further investigation.

Immobilization of Microbes for Bioremediation of Crude Oil Polluted Environments: A Mini Review

PubMed Central

Bayat, Zeynab; Hassanshahian, Mehdi; Cappello, Simone

2015-01-01

Petroleum hydrocarbons are the most common environmental pollutants in the world and oil spills pose a great hazard to terrestrial and marine ecosystems. Oil pollution may arise either accidentally or operationally whenever oil is produced, transported, stored and processed or used at sea or on land. Oil spills are a major menace to the environment as they severely damage the surrounding ecosystems. To improve the survival and retention of the bioremediation agents in the contaminated sites, bacterial cells must be immobilized. Immobilized cells are widely tested for a variety of applications. There are many types of support and immobilization techniques that can be selected based on the sort of application. In this review article, we have discussed the potential of immobilized microbial cells to degrade petroleum hydrocarbons. In some studies, enhanced degradation with immobilized cells as compared to free living bacterial cells for the treatment of oil contaminated areas have been shown. It was demonstrated that immobilized cell to be effective and is better, faster, and can be occurred for a longer period PMID:26668662

Biological methanol production by immobilized Methylocella tundrae using simulated biohythane as a feed.

PubMed

Patel, Sanjay K S; Singh, Raushan K; Kumar, Ashok; Jeong, Jae-Hoon; Jeong, Seong Hun; Kalia, Vipin C; Kim, In-Won; Lee, Jung-Kul

2017-10-01

Biohythane may be used as an alternative feed for methanol production instead of costly pure methane. In this study, methanol production potential of Methylocella tundrae immobilized through covalent immobilization, adsorption, and encapsulation was evaluated. Cells covalently immobilized on groundnut shells and chitosan showed a relative methanol production potential of 83.9 and 91.6%, respectively, compared to that of free cells. The maximum methanol production by free cells and cells covalently immobilized on groundnut shells and chitosan was 6.73, 6.20, and 7.23mM, respectively, using simulated biohythane as a feed. Under repeated batch conditions of eight cycles, cells covalently immobilized on chitosan and groundnut shells, and cells encapsulated in sodium-alginate resulted in significantly higher cumulative methanol production of 37.76, 31.80, and 25.58mM, respectively, than free cells (18.57mM). This is the first report on immobilization of methanotrophs on groundnut shells and its application in methanol production using biohythane as a feed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Immobilized humic substances and immobilized aggregates of humic substances as sorbent for solid phase extraction.

PubMed

Erny, Guillaume L; Gonçalves, Bruna M; Esteves, Valdemar I

2013-09-06

In this work, humic substances (HS) immobilized, as a thin layer or as aggregates, on silica gel were tested as material for solid phase extraction. Some triazines (simazine, atrazine, therbutylazine, atrazine-desethyl-desisopropyl-2-hydroxy, ametryn and terbutryn), have been selected as test analytes due to their environmental importance and to span a large range of solubility and octanol/water partition coefficient (logP). The sorbent was obtained immobilizing a thin layer of HS via physisorption on a pre-coated silica gel with a cationic polymer (polybrene). While the sorbent could be used as it is, it was demonstrated that additional HS could be immobilized, via weak interactions, to form stable humic aggregates. However, while a higher quantity of HS could be immobilized, no significant differences were observed in the sorption parameters. This sorbent have been tested for solid phase extraction to concentrate triazines from aqueous matrixes. The sorbent demonstrated performances equivalent to commercial alternatives as a concentration factor between 50 and 200, depending on the type of triazines, was obtained. Moreover the low cost and the high flow rate of sample through the column allowed using high quantity of sorbent. The analytical procedure was tested with different matrixes including tap water, river water and estuarine water. Copyright © 2013 Elsevier B.V. All rights reserved.

Preparation, characterization and catalytic behavior of pectinase covalently immobilized onto sodium alginate/graphene oxide composite beads.

PubMed

Dai, Xiao-Yan; Kong, Li-Min; Wang, Xiao-Ling; Zhu, Qing; Chen, Kai; Zhou, Tao

2018-07-01

Pectinase was immobilized onto sodium alginate/graphene oxide beads via amide bonds by using N,N'-dicyclohexylcarbodiimide/N-hydroxysuccinimide as the activating agent. The immobilized pectinase was characterized by Fourier transform infrared spectra and scanning electron microscopy analyses. Immobilization conditions were optimized by Box-Behnken design and the response surface method. The activity of the immobilized pectinase prepared under optimal conditions reached 1236.86 ± 40.21 U/g, with an enzyme activity recovery of 83.5%. The optimal pH of free pectinase was 4.5, while that of immobilized pectinase was shifted to 4.0. The optimal temperature of immobilized pectinase was increased to 60 °C, which was 10 °C higher than that of free form. Furthermore, the immobilized pectinase possessed a superior thermal stability and storage stability to those of free pectinase. Reusability studies indicated that the immobilized pectinase retained 73% of initial activity after six times cycles. Due to these good properties, such immobilized pectinase may find application in food industry. Copyright © 2018 Elsevier Ltd. All rights reserved.

A comparative study on decolorization of reactive azo and indigoid dyes by free/immobilized pellets of Trametes versicolor and Funalia trogii.

PubMed

Yildirim, Seval Cing; Yesilada, Ozfer

2015-11-01

The objective of the present study was to investigate decolorization of Acid Blue 74 and Reactive Blue 198 dyes by free and immobilized white rot fungal pellets in order to confirm the possibility of practical application via repeated-batch cultivation. Decolorization studies were conducted using free pellets (FP), fungal cells immobilized on activated carbon (IFCAC) and pinewood (IFCP), and also fungal cells entrapped in alginate beads (FCEAB). No additional nitrogen and carbon source was used and high decolorization rates were achieved in only dye-contained media without pH adjustment. Acid Blue 74 was decolorized 96 and 94% within 2 hr by Trametes versicolor and Funalia trogii free pellets, respectively. These values were 87 and 84% for Reactive Blue 198, in this respect. Immobilization of fungal cells on pinewood increased the usability of pellets and the average decolorization efficiency of both dyes. The micro environment changed in the presence of pinewood and increased the stability of immobilized pellets. Decolorization was performed rapidly and efficiently. Laccase activity enhanced with availability of pinewood, and high laccase production with F. trogii was obtained. After separation by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), the molecular weight of T versicolor and F. trogii laccase bands was determined 64 and 61 kDa approximately. Green bands were obtained by the activity staining process with laccase substrate (ABTS) after gel renaturation step.

Cytokine signaling pathway polymorphisms and AIDS-related non-Hodgkin lymphoma risk in the Multicenter AIDS Cohort Study

PubMed Central

Wong, Hui-Lee; Breen, Elizabeth C.; Pfeiffer, Ruth M.; Aissani, Brahim; Martinson, Jeremy J.; Margolick, Joseph B.; Kaslow, Richard A.; Jacobson, Lisa P.; Ambinder, Richard F.; Chanock, Stephen; Martínez-Maza, Otoniel; Rabkin, Charles S.

2014-01-01

Cytokine stimulation of B-cell proliferation may be an important etiologic mechanism for acquired immunodeficiency syndrome (AIDS)-related non-Hodgkin lymphoma (NHL). The Epstein-Barr virus may be a co-factor, particularly for primary central nervous system (CNS) tumors, which are uniformly EBV-positive in the setting of AIDS. Thus, we examined associations of genetic variation in IL10 and related cytokine signaling molecules (IL10RA, CXCL12, IL13, IL4, IL4R, CCL5 and BCL6) with AIDS-related NHL risk and evaluated differences between primary CNS and systemic tumors. We compared 160 Multicenter AIDS Cohort Study (MACS) participants with incident lymphomas, of which 90 followed another AIDS diagnosis, to HIV-1-seropositive controls matched on duration of lymphoma-free survival post-HIV-1 infection (N=160) or post-AIDS diagnosis (N=90). We fit conditional logistic regression models to estimate odds ratios (ORs) and 95 percent confidence intervals (95%CIs). Carriage of at least one copy of the T allele for the IL10 rs1800871 (as compared to no copies) was associated with decreased AIDS-NHL risk specific to lymphomas arising from the CNS (CC vs. CT/TT: OR=0.3; 95%CI: 0.1, 0.7) but not systemically (CC vs. CT/TT: OR=1.0; 95%CI: 0.5, 1.9) (Pheterogeneity=0.03). Carriage of two copies of the “low IL10” haplotype rs1800896_A/rs1800871_T/rs1800872_A was associated with decreased lymphoma risk that varied by number of copies (Ptrend=0.02). None of the ORs for the other studied polymorphisms was significantly different from 1.0. Excessive IL10 response to HIV-1 infection may be associated with increased risk of NHL, particularly in the CNS. IL10 dysregulation may be an important etiologic pathway for EBV-related lymphomagenesis. PMID:20299965

Utilization of immobilized urease for waste water treatment

NASA Technical Reports Server (NTRS)

Husted, R. R.

1974-01-01

The feasibility of using immobilized urease for urea removal from waste water for space system applications is considered, specifically the elimination of the urea toxicity problem in a 30-day Orbiting Frog Otolith (OFO) flight experiment. Because urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide, control of their concentrations within nontoxic limits was also determined. The results of this study led to the use of free urease in lieu of the immobilized urease for controlling urea concentrations. An ion exchange resin was used which reduced the NH3 level by 94% while reducing the sodium ion concentration only 10%.

Immobilization techniques to avoid enzyme loss from oxidase-based biosensors: a one-year study.

PubMed

House, Jody L; Anderson, Ellen M; Ward, W Kenneth

2007-01-01

Continuous amperometric sensors that measure glucose or lactate require a stable sensitivity, and glutaraldehyde crosslinking has been used widely to avoid enzyme loss. Nonetheless, little data is published on the effectiveness of enzyme immobilization with glutaraldehyde. A combination of electrochemical testing and spectrophotometric assays was used to study the relationship between enzyme shedding and the fabrication procedure. In addition, we studied the relationship between the glutaraldehyde concentration and sensor performance over a period of one year. The enzyme immobilization process by glutaraldehyde crosslinking to glucose oxidase appears to require at least 24-hours at room temperature to reach completion. In addition, excess free glucose oxidase can be removed by soaking sensors in purified water for 20 minutes. Even with the addition of these steps, however, it appears that there is some free glucose oxidase entrapped within the enzyme layer which contributes to a decline in sensitivity over time. Although it reduces the ultimate sensitivity (probably via a change in the enzyme's natural conformation), glutaraldehyde concentration in the enzyme layer can be increased in order to minimize this instability. After exposure of oxidase enzymes to glutaraldehyde, effective crosslinking requires a rinse step and a 24-hour incubation step. In order to minimize the loss of sensor sensitivity over time, the glutaraldehyde concentration can be increased.

Immobilization: A Revolution in Traditional Brewing

NASA Astrophysics Data System (ADS)

Virkajärvi, Ilkka; Linko, Matti

In nature many micro-organisms tend to bind to solid surfaces. This tendency has long been utilized in a number of processes, for example in producing vinegar and acetic acid in bioreactors filled with wood shavings. Acetobacteria are attached to the surface of these shavings. In modern technical language: they are immobilized. Also yeast cells can be immobilized. In the brewing industry this has been the basis for maintaining efficient, continuous fermentation in bioreactors with very high yeast concentrations. The most dramatic change in brewing over recent years has been the replacement of traditional lagering of several weeks by a continuous process in which the residence time is only about 2h. Continuous primary fermentation is used on a commercial scale in New Zealand. In this process, instead of a carrier, yeast is retained in reactors by returning it partly after separation. In many pilot scale experiments the primary fermentation is shortened from about 1week to 1-2days using immobilized yeast reactors. When using certain genetically modified yeast strains no secondary fermentation is needed, and the total fermentation time in immobilized yeast reactors can therefore be shortened to only 2days.

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.

Diesel oil removal by immobilized Pseudoxanthomonas sp. RN402.

PubMed

Nopcharoenkul, Wannarak; Netsakulnee, Parichat; Pinyakong, Onruthai

2013-06-01

Pseudoxanthomonas sp. RN402 was capable of degrading diesel, crude oil, n-tetradecane and n-hexadecane. The RN402 cells were immobilized on the surface of high-density polyethylene plastic pellets at a maximum cell density of 10(8) most probable number (MPN) g(-1) of plastic pellets. The immobilized cells not only showed a higher efficacy of diesel oil removal than free cells but could also degrade higher concentrations of diesel oil. The rate of diesel oil removal by immobilized RN402 cells in liquid culture was 1,050 mg l(-1) day(-1). Moreover, the immobilized cells could maintain high efficacy and viability throughout 70 cycles of bioremedial treatment of diesel-contaminated water. The stability of diesel oil degradation in the immobilized cells resulted from the ability of living RN402 cells to attach to material surfaces by biofilm formation, as was shown by CLSM imaging. These characteristics of the immobilized RN402 cells, including high degradative efficacy, stability and flotation, make them suitable for the purpose of continuous wastewater bioremediation.

Experimental joint immobilization in guinea pigs. Effects on the knee joint

NASA Technical Reports Server (NTRS)

Marcondesdesouza, J. P.; Machado, F. F.; Sesso, A.; Valeri, V.

1980-01-01

In young and adult guinea pigs, the aftermath experimentally induced by the immobilization of the knee joint in hyperextended forced position was studied. Joint immobilization which varied from one to nine weeks was attained by plaster. Eighty knee joints were examined macro and microscopically. Findings included: (1) muscular hypotrophy and joint stiffness in all animals, directly proportional to the length of immobilization; (2) haemoarthrosis in the first week; (3) intra-articular fibrous tissue proliferation ending up with fibrous ankylosis; (4) hyaline articular cartilage erosions; (5) various degrees of destructive menisci changes. A tentative explanation of the fibrous tissue proliferation and of the cartilage changes is offered.

Effect of linoleic-acid modified carboxymethyl chitosan on bromelain immobilization onto self-assembled nanoparticles

NASA Astrophysics Data System (ADS)

Tan, Yu-long; Liu, Chen-guang; Yu, Le-jun; Chen, Xi-guang

2008-06-01

Hydrogel nanoparticles could be prepared by using linoleic acid (LA) modified carboxymethyl chitosan (CMCS) after sonication. Bromelain could be loaded onto nanoparticles of LA-CMCS. Factors affecting the activity of the immobilized enzyme, including temperature, storage etc., were investigated in this study. The results showed that the stability of bromelain for heat and storage was improved after immobilization on nanoparticles. The Michaelis constant ( K m) of the immobilized enzyme was smaller than that of free enzyme, indicating that the immobilization could promote the stability of the enzyme and strengthen the affinity of the enzyme for the substrate.

Effects of immobilization and whole-body vibration on rat serum Type I collagen turnover.

PubMed

Dönmez, Gürhan; Doral, Mahmut Nedim; Suljevic, Şenay; Sargon, Mustafa Fevzi; Bilgili, Hasan; Demirel, Haydar Ali

2016-08-01

The aim of this study was to investigate the effects of short-term, high-magnitude whole-body vibration (WBV) on serum type I collagen turnover in immobilized rats. Thirty Wistar albino rats were randomly divided into the following 5 groups: immobilization (IS), immobilization + remobilization (IR), immobilization + WBV (IV), control (C), and WBV control (CV). Immobilization was achieved by casting from the crista iliaca anterior superior to the lower part of the foot for 2 weeks. The applied WBV protocol involved a frequency of 45 Hz and amplitude of 3 mm for 7 days starting a day after the end of the immobilization period. Serum type I collagen turnover markers were measured by using ELISA kits. Serum NH2-terminal propeptide of type I collagen (PINP) levels were significantly lower in the immobilization groups (p < 0.02) compared with the control groups. Although WBV improved PINP levels in the control groups, there were no differences in PINP levels among the immobilization groups. Similarly, serum COOH-terminal telopeptide of type I collagen (CTX) levels were higher in the WBV controls than their own controls (p < 0,05). Immobilization led to deterioration of tendon tissue, as observed by histopathological analysis with a transmission electron microscope. Although 1 week of WBV had a positive effect on type I collagen turnover in controls, it is not an efficient method for repairing tissue damage in the early stage following immobilization. Copyright © 2016 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

Astaxanthin supplementation attenuates immobilization-induced skeletal muscle fibrosis via suppression of oxidative stress.

PubMed

Maezawa, Toshiyuki; Tanaka, Masayuki; Kanazashi, Miho; Maeshige, Noriaki; Kondo, Hiroyo; Ishihara, Akihiko; Fujino, Hidemi

2017-09-01

Immobilization induces skeletal muscle fibrosis characterized by increasing collagen synthesis in the perimysium and endomysium. Transforming growth factor-β1 (TGF-β1) is associated with this lesion via promoting differentiation of fibroblasts into myofibroblasts. In addition, reactive oxygen species (ROS) are shown to mediate TGF-β1-induced fibrosis in tissues. These reports suggest the importance of ROS reduction for attenuating skeletal muscle fibrosis. Astaxanthin, a powerful antioxidant, has been shown to reduce ROS production in disused muscle. Therefore, we investigated the effects of astaxanthin supplementation on muscle fibrosis under immobilization. In the present study, immobilization increased the collagen fiber area, the expression levels of TGF-β1, α-smooth muscle actin, and superoxide dismutase-1 protein and ROS production. However, these changes induced by immobilization were attenuated by astaxanthin supplementation. These results indicate the effectiveness of astaxanthin supplementation on skeletal muscle fibrosis induced by ankle joint immobilization.

Lipase immobilization on epoxy-activated poly(vinyl acetate-acrylamide) microspheres.

PubMed

Zhang, Dong-Hao; Peng, Li-Juan; Wang, Yun; Li, Ya-Qiong

2015-05-01

Poly(vinyl acetate-acrylamide) microspheres with an average diameter of 2-4μm were successfully prepared and characterized via SEM and FTIR. Then the microspheres were modified with epoxy groups through reacting with epichlorohydrin and used as carriers to covalently immobilize Candida rugosa lipase. The results revealed that agitation played an important role on epoxy activation and the immobilization ratio increased with the increase of the epoxy density. On the other hand, the specific activity of the immobilized lipase as well as the activity recovery declined gradually with the increase in the immobilization ratio from 72% to 93%, which were attributed to the steric hindrance effects caused by enzyme overloading. When epoxy density was 76μmol/g microsphere, the activity recovery reached the maximum at 47.5%, and the activity of the immobilized lipase was 261.3U/g microsphere. Moreover, the thermal stability of the immobilized lipase was much better than that of the free one, which indicated potential applications of the immobilized lipase. Copyright © 2015 Elsevier B.V. All rights reserved.

Increase in stability of cellulase immobilized on functionalized magnetic nanospheres

NASA Astrophysics Data System (ADS)

Zhang, Wenjuan; Qiu, Jianhui; Feng, Huixia; Zang, Limin; Sakai, Eiichi

2015-02-01

Functionalized magnetic nanospheres were prepared by co-condensation of tetraethylorthosilicate with three different amino-silanes: 3-(2-aminoethylamino propyl)-triethoxysilane (AEAPTES), 3-(2-aminoethylamino propyl)-trimethoxysilane (AEAPTMES) and 3-aminopropyltriethoxysilane (APTES). Then three functionalized magnetic nanospheres were used as supports for immobilization of cellulase. The three functionalized magnetic nanospheres with core-shell morphologies exhibited higher capacity for cellulase immobilization than unfunctionalized magnetic nanospheres. The increasing of surface charge of functionalized magnetic nanospheres leads to an enhancement of the capacity of cellulase immobilization. Particularly, AEAPTMES with methoxy groups was favored to be hydrolyzed and grafted on unfunctionalized magnetic nanospheres than the others. AEAPTMES functionalized magnetic nanospheres with the highest zeta potential (29 mV) exhibited 87% activity recovery and the maximum amount of immobilized cellulase was 112 mg/g support at concentration of initial cellulase of 8 mg/mL. Immobilized cellulase on AEAPTMES functionalized magnetic nanospheres had higher temperature stability and broader pH stability than other immobilized cellulases and free cellulase. In particular, it can be used in about 40 °C, demonstrating the potential of biofuel production using this immobilized cellulase.

Application of carbon nanotubes to immobilize heavy metals in contaminated soils

NASA Astrophysics Data System (ADS)

Matos, Martim P. S. R.; Correia, António Alberto S.; Rasteiro, Maria G.

2017-04-01

The contamination of soils with heavy metals is a growing concern in modern societies. To avoid the spread of contamination, soil stabilization techniques can be applied mixing materials with the soil in order to partially immobilize heavy metals. Carbon nanotubes (CNTs) are nanomaterials known for its exceptional properties, like high surface area and adsorption capacity. Due to these unique properties, the potential use of CNTs in heavy metal contaminated water has been studied, with very satisfactory results; however, their application in contaminated soils is practically unexplored. This experimental work is focused on studying the potential of using CNTs in soil remediation, especially to immobilize the heavy metals ions: lead (Pb2+), copper (Cu2+), nickel (Ni2+), and zinc (Zn2+), commonly present in contaminated soils. In order to avoid CNT agglomeration, which originates the loss of their beneficial properties, an aqueous suspension of CNTs was prepared using a non-ionic surfactant combined with ultrasonic energy to promote CNTs dispersion. Then, the soil, with and without the addition of CNTs, was subjected to adsorption tests to evaluate the CNT capacity to improve heavy metal immobilization. To validate the adsorption test results, permeability tests were executed, simulating the conditions of a real-case scenario. The results obtained led to the conclusion that the addition of a small amount of dispersed CNTs can successfully increase the adsorption capacity of the soil and consequently improve the immobilization of heavy metals in the soil matrix. The immobilization percentage varies with the different heavy metals under study.

Sustainable biodegradation of phenol by immobilized Bacillus sp. SAS19 with porous carbonaceous gels as carriers.

PubMed

Ke, Qian; Zhang, Yunge; Wu, Xilin; Su, Xiaomei; Wang, Yuyang; Lin, Hongjun; Mei, Rongwu; Zhang, Yu; Hashmi, Muhammad Zaffar; Chen, Chongjun; Chen, Jianrong

2018-09-15

In this study, high-efficient phenol-degrading bacterium Bacillus sp. SAS19 which was isolated from activated sludge by resuscitation-promoting factor (Rpf) addition, were immobilized on porous carbonaceous gels (CGs) for phenol degradation. The phenol-degrading capabilities of free and immobilized Bacillus sp. SAS19 were evaluated under various initial phenol concentrations. The obtained results showed that phenol could be removed effectively by both free and immobilized Bacillus sp. SAS19. Furthermore, for degradation of phenol at high concentrations, long-term utilization and recycling were more readily achieved for immobilized bacteria as compared to free bacteria. Immobilized bacteria exhibited significant increase in phenol-degrading capabilities in the third cycle of recycling and reuse, which demonstrated 87.2% and 100% of phenol (1600 mg/L) degradation efficiency at 12 and 24 h, respectively. The present study revealed that immobilized Bacillus sp. SAS19 can be potentially used for enhanced treatment of synthetic phenol-laden wastewater. Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

Catalytical Properties of Free and Immobilized Aspergillus niger Tannase.

PubMed

Flores-Maltos, Abril; Rodríguez-Durán, Luis V; Renovato, Jacqueline; Contreras, Juan C; Rodríguez, Raúl; Aguilar, Cristóbal N

2011-01-01

A fungal tannase was produced, recovered, and immobilized by entrapment in calcium alginate beads. Catalytical properties of the immobilized enzyme were compared with those of the free one. Tannase was produced intracellularly by the xerophilic fungus Aspergillus niger GH1 in a submerged fermentation system. Enzyme was recovered by cell disruption and the crude extract was partially purified. The catalytical properties of free and immobilized tannase were evaluated using tannic acid and methyl gallate as substrates. K(M) and V(max) values for free enzyme were very similar for both substrates. But, after immobilization, K(M) and V(max) values increased drastically using tannic acid as substrate. These results indicated that immobilized tannase is a better biocatalyst than free enzyme for applications on liquid systems with high tannin content, such as bioremediation of tannery or olive-mill wastewater.

Catalytical Properties of Free and Immobilized Aspergillus niger Tannase

PubMed Central

Flores-Maltos, Abril; Rodríguez-Durán, Luis V.; Renovato, Jacqueline; Contreras, Juan C.; Rodríguez, Raúl; Aguilar, Cristóbal N.

2011-01-01

A fungal tannase was produced, recovered, and immobilized by entrapment in calcium alginate beads. Catalytical properties of the immobilized enzyme were compared with those of the free one. Tannase was produced intracellularly by the xerophilic fungus Aspergillus niger GH1 in a submerged fermentation system. Enzyme was recovered by cell disruption and the crude extract was partially purified. The catalytical properties of free and immobilized tannase were evaluated using tannic acid and methyl gallate as substrates. K M and V max values for free enzyme were very similar for both substrates. But, after immobilization, K M and V max values increased drastically using tannic acid as substrate. These results indicated that immobilized tannase is a better biocatalyst than free enzyme for applications on liquid systems with high tannin content, such as bioremediation of tannery or olive-mill wastewater. PMID:21918717

Immobilization of xanthine oxidase on a polyaniline silicone support.

PubMed

Nadruz, W; Marques, E T; Azevedo, W M; Lima-Filho, J L; Carvalho, L B

1996-03-01

A polyaniline silicone support to immobilize xanthine oxidase is proposed as a reactor coil to monitor the action of xanthine oxidase on hypoxanthine, xanthine and 6-mercaptopurine. A purified xanthine oxidase immobilized on this support lost 80% of the initial activity after 12 min of use. Co-immobilization of superoxide dismutase and catalase increased the stability of immobilized xanthine oxidase so that the derivative maintained 79% of its initial activity after 4.6 h of continuous use in which 1.5 mumol purine bases were converted by the immobilized enzyme system. There is no evidence of either polyaniline or protein leaching from the coil during 3 h of continuous use. When solutions (10 ml) of hypoxanthine, xanthine and 6-mercaptopurine were circulated individually through the xanthine oxidase-superoxide dismutase-catalase-polyaniline coil (1 mm internal diameter and 3 m in length, 3 ml internal volume) activities of 8.12, 11.17 and 1.09 nmol min-1 coil-1, respectively, were obtained. The advantages of the reactor configuration and the redox properties of the polymer, particularly with respect to immobilized oxidoreductases, make this methodology attractive for similar enzyme systems. This immobilized enzyme system using polyaniline-silicone as support converted 6-mercaptopurine to 6-thiouric acid with equal efficiency as resins based on polyacrylamide and polyamide 11.

Platform for immobilization and observation of subcellular processes

DOEpatents

McKnight, Timothy E.; Kalluri, Udaya C.; Melechko, Anatoli V.

2014-08-26

A method of immobilizing matter for imaging that includes providing an array of nanofibers and directing matter to the array of the nanofibers. The matter is immobilized when contacting at least three nanofibers of the array of nanofibers simultaneously. Adjacent nanofibers in the array of nanofibers may be separated by a pitch as great as 100 microns. The immobilized matter on the array of nanofibers may then be imaged. In some examples, the matter may be cell matter, such as protoplasts.

A Method for Immobilizing the Forelimbs of Rabbits.

PubMed

Thunder, Richard M.; Chang, James; Broome, Rosemary L.; Most, Daniel

1998-09-01

Immobilizing the forelimbs of rabbits after surgical procedures is necessary to allow healing, yet it often can be difficult, because rabbits are often able to pull the repaired limb from its cast soon after surgery and well before adequate tissue repair has taken place. We describe here a method of immobilization that uses 3 layers of cast material combined with flexion of the radiocarpal and radiohumeral joints. This method resulted in successful immobilization in 97% of the rabbits on which it was used.

Collagen-Immobilized Lipases Show Good Activity and Reusability for Butyl Butyrate Synthesis.

PubMed

Dewei, Song; Min, Chen; Haiming, Cheng

2016-11-01

Candida rugosa lipases were immobilized onto collagen fibers through glutaraldehyde cross-linking method. The immobilization process has been optimized. Under the optimal immobilization conditions, the activity of the collagen-immobilized lipase reached 340 U/g. The activity was recovered of 28.3 % by immobilization. The operational stability of the obtained collagen-immobilized lipase for hydrolysis of olive oil emulsion was determined. The collagen-immobilized lipase showed good tolerance to temperature and pH variations in comparison to free lipase. The collagen-immobilized lipase was also applied as biocatalyst for synthesis of butyl butyrate from butyric acid and 1-butanol in n-hexane. The conversion yield was 94 % at the optimal conditions. Of its initial activity, 64 % was retained after 5 cycles for synthesizing butyl butyrate in n-hexane.

IN SITU LEAD IMMOBILIZATION BY APATITE

EPA Science Inventory

Lead contamination is of environmental concern due to its effect on human health. The purpose of this study was to develop a technology to immobilize Pb in situ in contaminated soils and wastes using apatite. Hydroxyapatite [Ca₁₀(PO₄)₆(O...

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

The Effect of Student Aid on the Duration of Study

ERIC Educational Resources Information Center

Glocker, Daniela

2011-01-01

In this paper I evaluate the effect of student aid on the success of academic studies. I focus on two dimensions, the duration of study and the probability of actually graduating with a degree. To determine the impact of financial student aid, I estimate a discrete-time duration model allowing for competing risks to account for different exit…

Anti-stress effects of cilnidipine and nimodipine in immobilization subjected mice.

PubMed

Kumar, Naresh; Singh, Nirmal; Jaggi, Amteshwar Singh

2012-03-20

The present study was designed to investigate the ameliorative role of cilnidipine and nimodipine in immobilization stress-induced behavioral alterations and memory defects in the mice. Acute stress was induced by immobilizing the mice for 150 min and stress-induced behavioral changes were assessed using actophotometer, hole board, open field and social interaction tests. The learning and memory was evaluated using elevated plus maze tests and biochemically, the corticosterone levels were measured in the blood serum. Acute immobilization stress resulted in decrease in locomotor activity, frequency of head dips and rearings in hole board; line crossing and rearing in the open field; increase in avoidance in social behavior along with development of memory deficits assessed by an increased transfer latency time and elevation of the corticosterone levels. Administration of cilnidipine (10 mg/kg), an L and N-type dual calcium channel blocker, and nimodipine (10 mg/kg), an L-type calcium channel blocker, significantly attenuated the immobilized stress-induced behavioral changes and restored memory deficits along with normalization of the corticosterone levels. Cilnidipine and nimodipine produced comparable beneficial effects in restoring immobilization stress subjected mice. It may be concluded that cilnidipine and nimodipine mediated attenuation of corticosterone release by blockage of calcium channels (both L and N-type) on the HPA-axis is responsible for beneficial effects in restoration of behavioral alterations and memory deficits in immobilization-induced acute stress in mice. Copyright © 2011 Elsevier Inc. All rights reserved.

Activity-related energy expenditure during lower limb cast immobilization in children.

PubMed

Maggio, Albane B; Martin, Xavier E; Ceroni, Dimitri

2017-05-01

Physical inactivity, which may result from immobilization, is recognized as a risk factor for the development of obesity. We aimed to quantify the decrease in activity-related energy expenditure (AEE) because of lower limb cast immobilization. We carried out a longitudinal matched case-control study: 34 adolescents with a first episode of lower limb fracture and 34 healthy cases. Physical activity was assessed during cast immobilization by an accelerometer from which we calculated the decrease in AEE. AEE in adolescents with lower limb fractures was estimated to be 16.0% lower than healthy controls. When converted into kcal per mean participants' weight, the difference in AEE amounted to 125 kcal/day, which corresponds to 5.2 h of slow walking. A significant reduction of AEE in adolescents with lower limb fractures may lead to a significantly positive energy balance as there is usually no compensatory reduction of energy intake. An increase of walking seems unrealistic in this situation and patients should be advised at the emergency unit to reduce their energy intake during the immobilization period. Level III, prospective case-control study.

Purification, immobilization, and characterization of nattokinase on PHB nanoparticles.

PubMed

Deepak, Venkataraman; Pandian, Suresh babu Ram Kumar; Kalishwaralal, Kalimuthu; Gurunathan, Sangiliyandi

2009-12-01

In this study, nattokinase was purified from Bacillus subtilis using ion exchange chromatography and immobilized upon polyhydroxybutyrate (PHB) nanoparticles. A novel strain isolated from industrial dairy waste was found to synthesize polyhydroxyalkanoates (PHA) and the strain was identified as Brevibacterium casei SRKP2. PHA granules were extracted from 48 h culture and the FT-IR analysis characterized them as PHB, a natural biopolymer from B. casei. Nanoprecipitation by solvent displacement technique was used to synthesize PHB nanoparticles. PHB nanoparticles were characterized using transmission electron microscopy and particle size ranged from 100-125 nm. Immobilization of nattokinase upon PHB nanoparticles resulted in a 20% increase in the enzyme activity. Immobilization also contributed to the enhanced stability of the enzyme. Moreover, the activity was completely retained on storage at 4 degrees C for 25 days. The method has proven to be highly simple and can be implemented to other enzymes also.

Enzyme immobilization and biocatalysis of polysiloxanes

NASA Astrophysics Data System (ADS)

Poojari, Yadagiri

Lipases have been proven to be versatile and efficient biocatalysts which can be used in a broad variety of esterification, transesterification, and ester hydrolysis reactions. Due to the high chemo-, regio-, and stereo-selectivity and the mild conditions of lipase-catalyzed reactions, the vast potential of these biocatalysts for use in industrial applications has been increasingly recognized. Polysiloxanes (silicones) are well known for their unique physico-chemical properties and can be prepared in the form of fluids, elastomers, gels and resins for a wide variety of applications. However, the enzymatic synthesis of silicone polyesters and copolymers is largely unexplored. In the present investigations, an immobilized Candida antarctica lipase B (CALB) on macroporous acrylic resin beads (Novozym-435 RTM) has been successfully employed as a catalyst to synthesize silicone polyesters and copolymers under mild reaction conditions. The silicone aliphatic polyesters and the poly(dimethylsiloxane)--poly(ethylene glycol) (PDMS-PEG) copolymers were synthesized in the bulk (without using a solvent), while the silicone aromatic polyesters, the silicone aromatic polyamides and the poly(epsilon-caprolactone)--poly(dimethylsiloxane)--poly(epsilon-caprolactone) (PCL-PDMS-PCL) triblock copolymers were synthesized in toluene. The synthesized silicone polyesters and copolymers were characterized by Gel Permeation Chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Wide Angle X-ray Diffraction (WAXD). This dissertation also describes a methodology for physical immobilization of the enzyme pepsin from Porcine stomach mucosa in silicone elastomers utilizing condensation-cure room temperature vulcanization (RTV) of silanol-terminated poly(dimethylsiloxane) (PDMS). The activity and the stability of free pepsin and pepsin immobilized in silicone elastomers were studied with respect to p

Lindane removal by pure and mixed cultures of immobilized actinobacteria.

PubMed

Saez, Juliana M; Benimeli, Claudia S; Amoroso, María J

2012-11-01

Lindane (γ-HCH) is an organochlorine insecticide that has been widely used in developing countries. It is known to persist in the environment and can cause serious health problems. One of the strategies adopted to remove lindane from the environment is bioremediation using microorganisms. Immobilized cells present advantages over free suspended cells, like their high degradation efficiency and protection against toxins. The aims of this work were: (1) To evaluate the ability of Streptomyces strains immobilized in four different matrices to remove lindane, (2) To select the support with optimum lindane removal by pure cultures, (3) To assay the selected support with consortia and (4) To evaluate the reusability of the immobilized cells. Four Streptomyces sp. strains had previously shown their ability to grow in the presence of lindane. Lindane removal by microorganisms immobilized was significantly higher than in free cells. Specifically immobilized cells in cloth sachets showed an improvement of around 25% in lindane removal compared to the abiotic control. Three strains showed significantly higher microbial growth when they were entrapped in silicone tubes. Strains immobilized in PVA-alginate demonstrated lowest growth. Mixed cultures immobilized inside cloth sachets showed no significant enhancement compared to pure cultures, reaching a maximum removal of 81% after 96 h for consortium I, consisting of the four immobilized strains together. Nevertheless, the cells could be reused for two additional cycles of 96 h each, obtaining a maximum removal efficiency of 71.5% when each of the four strains was immobilized in a separate bag (consortium III). Copyright © 2012 Elsevier Ltd. All rights reserved.

Haloalkane hydrolysis with an immobilized haloalkane dehalogenase.

PubMed

Dravis, B C; Swanson, P E; Russell, A J

2001-11-20

Haloalkane dehalogenase from Rhodococcus rhodochrous was covalently immobilized onto a polyethyleneimine impregnated gamma-alumina support. The dehalogenating enzyme was found to retain greater than 40% of its original activity after immobilization, displaying an optimal loading (max. activity/supported protein) of 70 to 75 mg/g with an apparent maximum (max. protein/support) of 156 mg/g. The substrate, 1,2,3-trichloropropane, was found to favorably partition (adsorb) onto the inorganic alumina carrier (10 to 20 mg/g), thereby increasing the local reactant concentration with respect to the catalyst's environment, whereas the product, 2,3-dichloropropan-1-ol, demonstrated no affinity. Additionally, the inorganic alumina support exhibited no adverse effects because of solvent/component incompatibilities or deterioration due to pH variance (pH 7.0 to 10.5). As a result of the large surface area to volume ratio of the support matrix and the accessibility of the bound protein, the immobilized biocatalyst was not subject to internal mass transfer limitations. External diffusional restrictions could be eliminated with simple agitation (mixing speed: 50 rpm; flux: 4.22 cm/min). The pH-dependence of the immobilized dehalogenase was essentially the same as that for the native enzyme. Finally, both the thermostability and resistance toward inactivation by organic solvent were improved by more than an order of magnitude after immobilization. Copyright 2001 John Wiley & Sons, Inc.

Biohydrogen production from rotten orange with immobilized mixed culture: Effect of immobilization media for various composition of substrates

NASA Astrophysics Data System (ADS)

Damayanti, Astrilia; Sarto, Syamsiah, Siti; Sediawan, Wahyudi B.

2015-12-01

Enriched-immobilized mixed culture was utilized to produce biohydrogen in mesophilic condition under anaerobic condition using rotten orange as substrate. The process was conducted in batch reactors for 100 hours. Microbial cultures from three different sources were subject to a series of enrichment and immobilized in two different types of media, i.e. calcium alginate (CA, 2%) and mixture of alginate and activated carbon (CAC, 1:1). The performance of immobilized culture in each media was tested for biohydrogen production using four different substrate compositions, namely orange meat (OM), orange meat added with peel (OMP), orange meat added with limonene (OML), and mixture of orange meat and peel added with limonene (OMPL). The results show that, with immobilized culture in CA, the variation of substrate composition gave significant effect on the production of biohydrogen. The highest production of biohydrogen was detected for substrate containing only orange meet, i.e. 2.5%, which was about 3-5 times higher than biohydrogen production from other compositions of substrate. The use of immobilized culture in CAC in general has increased the hydrogen production by 2-7 times depending on the composition of substrate, i.e. 5.4%, 4.8%, 5.1%, and 4.4% for OM, OMP, OML, and OMPL, respectively. The addition of activated carbon has eliminated the effect of inhibitory compounds in the substrate. The major soluble metabolites were acetic acid, propionic acid, and butyric acid.

Biohydrogen production from rotten orange with immobilized mixed culture: Effect of immobilization media for various composition of substrates

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

Damayanti, Astrilia, E-mail: liasholehasd@gmail.com; Department of Chemical Engineering, Faculty of Engineering, Gadjah Mada University, Jl. Grafika No. 2, Kampus UGM, Yogyakarta 55281; Sarto,

Enriched–immobilized mixed culture was utilized to produce biohydrogen in mesophilic condition under anaerobic condition using rotten orange as substrate. The process was conducted in batch reactors for 100 hours. Microbial cultures from three different sources were subject to a series of enrichment and immobilized in two different types of media, i.e. calcium alginate (CA, 2%) and mixture of alginate and activated carbon (CAC, 1:1). The performance of immobilized culture in each media was tested for biohydrogen production using four different substrate compositions, namely orange meat (OM), orange meat added with peel (OMP), orange meat added with limonene (OML), and mixturemore » of orange meat and peel added with limonene (OMPL). The results show that, with immobilized culture in CA, the variation of substrate composition gave significant effect on the production of biohydrogen. The highest production of biohydrogen was detected for substrate containing only orange meet, i.e. 2.5%, which was about 3-5 times higher than biohydrogen production from other compositions of substrate. The use of immobilized culture in CAC in general has increased the hydrogen production by 2-7 times depending on the composition of substrate, i.e. 5.4%, 4.8%, 5.1%, and 4.4% for OM, OMP, OML, and OMPL, respectively. The addition of activated carbon has eliminated the effect of inhibitory compounds in the substrate. The major soluble metabolites were acetic acid, propionic acid, and butyric acid.« less

Synthesis and properties of immobilized pectinase onto the macroporous polyacrylamide microspheres.

PubMed

Lei, Zhongli; Jiang, Qin

2011-03-23

Pectinase was covalently immobilized onto the macroporous polyacrylamide (PAM) microspheres synthesized via an inverse suspension polymerization approach, resulting in 81.7% immobilization yield. The stability of the macroporous PAM support, which has a large surface area, is not impeded by the adsorbed proteins despite the fact that up to 296.3 mg of enzyme is immobilized per gram of the carrier particles. The immobilized enzyme retained more than 75% of its initial activity over 30 days, and the optimum temperature/pH also increased to the range of 50-60 °C/3.0-5.0. The immobilized enzyme also exhibited great operational stability, and more than 75% residual activity was observed after 10 batch reactions. The kinetics of a model reaction catalyzed by the immobilized pectinase was finally investigated. Moreover, the immobilized pectinase could be recovered by centrifuging and showed durable activity at the process of recycle.

Analysis of alternatives for immobilized low activity waste disposal

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

Burbank, D.A.

This report presents a study of alternative disposal system architectures and implementation strategies to provide onsite near-surface disposal capacity to receive the immobilized low-activity waste produced by the private vendors. The analysis shows that a flexible unit strategy that provides a suite of design solutions tailored to the characteristics of the immobilized low-activity waste will provide a disposal system that best meets the program goals of reducing the environmental, health, and safety impacts; meeting the schedule milestones; and minimizing the life-cycle cost of the program.

Laboratory assessment of bioleaching of shallow eutrophic sediment by immobilized photosynthetic bacteria.

PubMed

Sun, Shiyong; Fan, Shenglan; Shen, Kexuan; Lin, Shen; Nie, Xiaoqin; Liu, Mingxue; Dong, Faqin; Li, Jian

2017-10-01

Eutrophic sediment is a serious problem in ecosystem restoration, especially in shallow lake ecosystems. We present a novel bioleaching approach to treat shallow eutrophic sediment with the objective of preventing the release of nitrate, phosphate, and organic compounds from the sediment to the water column, using porous mineral-immobilized photosynthetic bacteria (PSB). Bioactivity of bacteria was maintained during the immobilization process. Immobilized PSB beads were directly deposited on the sediment surface. The deposited PSB utilized pollutants diffused from the sediment as a nutritive matrix for growth. We evaluated the effects of light condition, temperature, initial pH, amount of PSB beads, and frequency of addition of PSB beads for contaminant removal efficiency during bioleaching operations. The presented study indicated that immobilized PSB beads using porous minerals as substrates have considerable application potential in bioremediation of shallow eutrophic lakes.

On-chip immobilization of planarians for in vivo imaging.

PubMed

Dexter, Joseph P; Tamme, Mary B; Lind, Christine H; Collins, Eva-Maria S

2014-09-17

Planarians are an important model organism for regeneration and stem cell research. A complete understanding of stem cell and regeneration dynamics in these animals requires time-lapse imaging in vivo, which has been difficult to achieve due to a lack of tissue-specific markers and the strong negative phototaxis of planarians. We have developed the Planarian Immobilization Chip (PIC) for rapid, stable immobilization of planarians for in vivo imaging without injury or biochemical alteration. The chip is easy and inexpensive to fabricate, and worms can be mounted for and removed after imaging within minutes. We show that the PIC enables significantly higher-stability immobilization than can be achieved with standard techniques, allowing for imaging of planarians at sub-cellular resolution in vivo using brightfield and fluorescence microscopy. We validate the performance of the PIC by performing time-lapse imaging of planarian wound closure and sequential imaging over days of head regeneration. We further show that the device can be used to immobilize Hydra, another photophobic regenerative model organism. The simple fabrication, low cost, ease of use, and enhanced specimen stability of the PIC should enable its broad application to in vivo studies of stem cell and regeneration dynamics in planarians and Hydra.

On-chip immobilization of planarians for in vivo imaging

PubMed Central

Dexter, Joseph P.; Tamme, Mary B.; Lind, Christine H.; Collins, Eva-Maria S.

2014-01-01

Planarians are an important model organism for regeneration and stem cell research. A complete understanding of stem cell and regeneration dynamics in these animals requires time-lapse imaging in vivo, which has been difficult to achieve due to a lack of tissue-specific markers and the strong negative phototaxis of planarians. We have developed the Planarian Immobilization Chip (PIC) for rapid, stable immobilization of planarians for in vivo imaging without injury or biochemical alteration. The chip is easy and inexpensive to fabricate, and worms can be mounted for and removed after imaging within minutes. We show that the PIC enables significantly higher-stability immobilization than can be achieved with standard techniques, allowing for imaging of planarians at sub-cellular resolution in vivo using brightfield and fluorescence microscopy. We validate the performance of the PIC by performing time-lapse imaging of planarian wound closure and sequential imaging over days of head regeneration. We further show that the device can be used to immobilize Hydra, another photophobic regenerative model organism. The simple fabrication, low cost, ease of use, and enhanced specimen stability of the PIC should enable its broad application to in vivo studies of stem cell and regeneration dynamics in planarians and Hydra. PMID:25227263

Evaluation of free and immobilized Aspergillus niger NRC1ami pectinase applicable in industrial processes.

PubMed

Esawy, Mona A; Gamal, Amira A; Kamel, Zeinat; Ismail, Abdel-Mohsen S; Abdel-Fattah, Ahmed F

2013-02-15

The Aspergillus niger NRC1ami pectinase was evaluated according to its hydrolysis efficiency of dry untreated orange peels (UOP), HCl-treated orange peels and NaOH-treated orange peels (HOP and NOP). Pectinase was entrapped in polyvinyl alcohol (PVA) sponge and the optimum pH and temperature of the free and immobilized enzymes were shifted from 4, 40 °C to 6, 50 °C respectively. The study of pH stability of free and immobilized pectinase showed that the immobilization process protected the enzyme strongly from severe alkaline pHs. The immobilization process improved the enzyme thermal stability to great instant. The unique feature of the immobilization process is its ability to solve the orange juice haze problem completely. Immobilized enzyme was reused 12 times in orange juice clarification with 9% activity loss from the original activity. Maximum reaction rate (V(max)) and Michaelis-Menten constant (K(m)) of the partially purified form were significantly changed after immobilization. Copyright © 2012 Elsevier Ltd. All rights reserved.

Oral Language Comprehension Using Hearing Aids and Tactile Aids: Three Case Studies.

ERIC Educational Resources Information Center

Proctor, Adele

1990-01-01

Three prelinguistic, profoundly deaf children (aged three to four) used a wearable, single channel, vibrotactile communication aid in conjunction with hearing aids during individual speech and language therapy at school. Subjects exhibited a faster than average rate of learning to understand spoken language after the onset of vibrotactile…

Protic ionic liquid as additive on lipase immobilization using silica sol-gel.

PubMed

de Souza, Ranyere Lucena; de Faria, Emanuelle Lima Pache; Figueiredo, Renan Tavares; Freitas, Lisiane dos Santos; Iglesias, Miguel; Mattedi, Silvana; Zanin, Gisella Maria; dos Santos, Onélia Aparecida Andreo; Coutinho, João A P; Lima, Álvaro Silva; Soares, Cleide Mara Faria

2013-03-05

Ionic liquids (ILs) have evolved as a new type of non-aqueous solvents for biocatalysis, mainly due to their unique and tunable physical properties. A number of recent review papers have described a variety of enzymatic reactions conducted in IL solutions, on the other hand, to improve the enzyme's activity and stability in ILs; major methods being explored include the enzyme immobilization (on solid support, sol-gel, etc.), protic ionic liquids used as an additive process. The immobilization of the lipase from Burkholderia cepacia by the sol-gel technique using protic ionic liquids (PIL) as additives to protect against inactivation of the lipase due to release of alcohol and shrinkage of the gel during the sol-gel process was investigated in this study. The influence of various factors such as the length of the alkyl chain of protic ionic liquids (monoethanolamine-based) and a concentration range between 0.5 and 3.0% (w/v) were evaluated. The resulting hydrophobic matrices and immobilized lipases were characterised with regard to specific surface area, adsorption-desorption isotherms, pore volume (V(p)) and size (d(p)) according to nitrogen adsorption and scanning electron microscopy (SEM), physico-chemical properties (thermogravimetric - TG, differential scanning calorimetry - DSC and Fourier transform infrared spectroscopy - FTIR) and the potential for ethyl ester and emulsifier production. The total activity yields (Y(a)) for matrices of immobilized lipase employing protic ionic liquids as additives always resulted in higher values compared with the sample absent the protic ionic liquids, which represents 35-fold increase in recovery of enzymatic activity using the more hydrophobic protic ionic liquids. Compared with arrays of the immobilized biocatalyst without additive, in general, the immobilized biocatalyst in the presence of protic ionic liquids showed increased values of surface area (143-245 m(2) g(-1)) and pore size (19-38 Å). Immobilization with

Controlling enzymatic activity by immobilization on graphene oxide

NASA Astrophysics Data System (ADS)

Bolibok, Paulina; Wiśniewski, Marek; Roszek, Katarzyna; Terzyk, Artur P.

2017-04-01

In this study, graphene oxide (GO) has been applied as a matrix for enzyme immobilization. The protein adsorption capacity of GO is much higher than of other large surface area carbonaceous materials. Its structure and physicochemical properties are reported beneficial also for enzymatic activity modifications. The experimental proof was done here that GO-based biocatalytic systems with immobilized catalase are modifiable in terms of catalyzed reaction kinetic constants. It was found that activity and stability of catalase, considered here as model enzyme, closely depend on enzyme/GO ratio. The changes in kinetic parameters can be related to secondary structure alterations. The correlation between enzyme/GO ratio and kinetic and structure parameters is reported for the first time and enables the conscious control of biocatalytic processes and their extended applications. The biological activity of obtained biocatalytic systems was confirmed in vitro by the use of functional test. The addition of immobilized catalase improved the cells' viability after they were exposed to hydrogen peroxide and tert-butyl-hydroperoxide used as source of reactive oxygen species.

Aryl diazonium for biomolecules immobilization onto SPRi chips.

PubMed

Mandon, Céline A; Blum, Loïc J; Marquette, Christophe A

2009-12-21

A method for the immobilization of proteins at the surface of surface plasmon resonance imaging (SPRi) chips is presented. The technology, based on the electro-deposition of a 4-carboxymethyl aryl diazonium (CMA) monolayer is compared to a classical thioctic acid self-assembled monolayer. SPRi live recording experiments followed by the quantification of the diazonium surface coverage demonstrate the presence of a monolayer of electro-deposited molecules (11*10(12) molecules mm(-2)). This monolayer, when activated through a classical carbodiimide route, generates a surface suitable for the protein immobilization. In the present study, protein A and BSA are immobilized as specific and control spots (150 microm id), respectively. The AFM characterization of the spots deposited onto CMA or thioctic acid modified chips prove the presence of 4.7 nm protein monolayers. Finally, the SPRi detection capabilities of the two surface chemistries are compared according to specific signal, non-specific interaction and regeneration possibilities. Advantages are given to the CMA surface modification since no measurable non-specific signal is obtained while reaching a higher specific signal.

Factors Influencing Hearing Aid Use in the Classroom: A Pilot Study.

PubMed

Gustafson, Samantha J; Davis, Hilary; Hornsby, Benjamin W Y; Bess, Fred H

2015-12-01

This pilot study examined factors influencing classroom hearing aid use in school-age children with hearing loss. The research team visited classrooms of 38 children with mild-to-moderate hearing loss (Grades 1-7) on 2 typical school days, twice per day, to document hearing aid use. In addition, parents reported the number of hours their children used hearing aids at school. Nearly 24% of children were observed not wearing their hearing aids in the classroom on either observation day. Both grade level and degree of hearing loss appeared to affect hearing aid use. Children in Grades 5-7 and those with milder hearing losses were less likely to wear hearing aids. Overall, parents accurately reported classroom hearing aid use; however, those with children in Grades 5-7 were less accurate than those with children in earlier grades. These preliminary results suggest that children with milder hearing loss and those in Grades 5-7 are at increased risk for reduced hearing aid use in the classroom. Also, parents of school-age children in these later grades are less accurate reporters of classroom hearing aid use compared to parents of children in earlier grades.

Dye decolorization and detoxification potential of Ca-alginate beads immobilized manganese peroxidase.

PubMed

Bilal, Muhammad; Asgher, Muhammad

2015-12-10

In view of compliance with increasingly stringent environmental legislation, an eco-friendly treatment technology of industrial dyes and effluents is a major environmental challenge in the color industry. In present study, a promising and eco-friendly entrapment approach was adopted to immobilize purified manganese peroxidase (MnP) produced from an indigenous strain of Ganoderma lucidum IBL-05 on Ca-alginate beads. The immobilized MnP was subsequently used for enhanced decolorization and detoxification of textile reactive dyes). MnP isolated from solid-state culture of G. lucidum IBL-05, presented highest immobilization yield (83.9 %) using alginate beads prepared at optimized conditions of 4 % (w/v) sodium alginate, 2 % (w/v) Calcium chloride (CaCl2) and 0.5 mg/ml enzyme concentration. Immobilization of MnP enhanced optimum temperature but caused acidic shift in optimum pH of the enzyme. The immobilized MnP showed optimum activity at pH 4.0 and 60 °C as compared to pH 5.0 and 35 °C for free enzyme. The kinetic parameters K(m) and V(max) of MnP were significantly improved by immobilization. The enhanced catalytic potential of immobilized MnP led to 87.5 %, 82.1 %, 89.4 %, 95.7 % and 83 % decolorization of Sandal-fix Red C4BLN, Sandal-fix Turq Blue GWF, Sandal-fix Foron Blue E2BLN, Sandal-fix Black CKF and Sandal-fix Golden Yellow CRL dyes, respectively. The insolubilized MnP was reusable for 7 repeated cycles in dye color removal. Furthermore, immobilized MnP also caused a significant reduction in biochemical oxygen demand (BOD) (94.61-95.47 %), chemical oxygen demand (COD) (91.18-94.85 %), and total organic carbon (TOC) (89.58-95 %) of aqueous dye solutions. G. lucidum MnP was immobilized in Ca-alginate beads by entrapment method to improve its practical effectiveness. Ca-alginate bound MnP was catalytically more vigorous, thermo-stable, reusable and worked over wider ranges of pH and temperature as compared to its free counterpart. Results of cytotoxicity like

Engineering cholesterol-based fibers for antibody immobilization and cell capture

NASA Astrophysics Data System (ADS)

Cohn, Celine

abilities of the CSS fibers were compared to that of hydrophobic polycaprolactone (PCL) fibers and hydrophilic plasma-treated PCL fibers. Electrospun CSS fibers were found to immobilize equivalent amounts of protein as hydrophobically immobilized proteins. However, these proteins captured 6 times more cells, indicative of retained protein function. The second key concept was the design and fabrication of a hybridized lipid fiber. Lipid fibers provide improved protein function but fabrication difficulties have limited their adoption. Thus, we sought to fabricate a lipid-polymer hybrid that is easily fabricated while maintaining protein function. The hybrid fiber consists of a PCL backbone with conjugated CSS. The hybrid lipid fibers showed improved protein function. In addition, higher lipid concentrations were directly correlated to higher cell capture efficiencies. The third key concept was on the development of dually functionalized lipid fibers and understanding the resulting cell capture efficiencies. Many platforms are unable to simultaneously search for heterogeneous populations of CTCs -- the ability to dually functionalize cell-capturing platforms would address this technological weakness. Studies indicated that dually functionalizing the lipid fibers did not compromise the platforms' abilities to capture the cells of interest. Such dually functionalized fibers allow for a single cell-capture platform to successfully detect heterogeneous populations of CTCs. The body of work encompassed herein describes the use of lipid fibers for antibody immobilization and cell capture. Data from various projects indicate that the use of cholesterol-based fibers produced from electrospun CSS are well suited for protein immobilization. The CSS fibers are able to immobilize equivalent amounts of protein as compared to other immobilization techniques. However, the benefit of these fibers is illustrated by the strong cell-capturing efficiencies, indicating that the immobilized

In-situ evidence for uranium immobilization and remobilization

USGS Publications Warehouse

Senko, John M.; Istok, Jonathan D.; Suflita, Joseph M.; Krumholz, Lee R.

2002-01-01

The in-situ microbial reduction and immobilization of uranium was assessed as a means of preventing the migration of this element in the terrestrial subsurface. Uranium immobilization (putatively identified as reduction) and microbial respiratory activities were evaluated in the presence of exogenous electron donors and acceptors with field push−pull tests using wells installed in an anoxic aquifer contaminated with landfill leachate. Uranium(VI) amended at 1.5 μM was reduced to less than 1 nM in groundwater in less than 8 d during all field experiments. Amendments of 0.5 mM sulfate or 5 mM nitrate slowed U(VI) immobilization and allowed for the recovery of 10% and 54% of the injected element, respectively, as compared to 4% in the unamended treatment. Laboratory incubations confirmed the field tests and showed that the majority of the U(VI) immobilized was due to microbial reduction. In these tests, nitrate treatment (7.5 mM) inhibited U(VI) reduction, and nitrite was transiently produced. Further push−pull tests were performed in which either 1 or 5 mM nitrate was added with 1.0 μM U(VI) to sediments that already contained immobilized uranium. After an initial loss of the amendments, the concentration of soluble U(VI) increased and eventually exceeded the injected concentration, indicating that previously immobilized uranium was remobilized as nitrate was reduced. Laboratory experiments using heat-inactivated sediment slurries suggested that the intermediates of dissimilatory nitrate reduction (denitrification or dissimilatory nitrate reduction to ammonia), nitrite, nitrous oxide, and nitric oxide were all capable of oxidizing and mobilizing U(IV). These findings indicate that in-situ subsurface U(VI) immobilization can be expected to take place under anaerobic conditions, but the permanence of the approach can be impaired by disimilatory nitrate reduction intermediates that can mobilize previously reduced uranium.

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.

Recovery of uranium from seawater by immobilized tannin

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

Sakaguchi, T.; Nakajima, A.

1987-06-01

Tannin compounds having multiple adjacent hydroxy groups have an extremely high affinity for uranium. To prevent the leaching of tannins into water and to improve the adsorbing characteristics of these compounds, the authors tried to immobilize tannins. The immobilized tannin has the most favorable features for uranium recovery; high selective adsorption ability to uranium, rapid adsorption rate, and applicability in both column and batch systems. The immobilized tannin can recover uranium from natural seawater with high efficiency. About 2530 ..mu..g uranium is adsorbed per gram of this adsorbent within 22 h. Depending on the concentration in seawater, an enrichment ofmore » up to 766,000-fold within the adsorbent is possible. Almost all uranium adsorbed is easily desorbed with a very dilute acid. Thus, the immobilized tannin can be used repeatedly in the adsorption-desorption process.« less

Production of L-glutamic Acid with Corynebacterium glutamicum (NCIM 2168) and Pseudomonas reptilivora (NCIM 2598): A Study on Immobilization and Reusability

PubMed Central

Shyamkumar, Rajaram; Moorthy, Innasi Muthu Ganesh; Ponmurugan, Karuppiah; Baskar, Rajoo

2014-01-01

Background L-glutamic acid is one of the major amino acids that is present in a wide variety of foods. It is mainly used as a food additive and flavor enhancer in the form of sodium salt. Corynebacterium glutamicum (C. glutamicum) is one of the major organisms widely used for glutamic acid production. Methods The study was dealing with immobilization of C. glutamicum and mixed culture of C. glutamicum and Pseudomonas reptilivora (P. reptilivora) for L-glutamic acid production using submerged fermentation. 2, 3 and 5% sodium alginate concentrations were used for production and reusability of immobilized cells for 5 more trials. Results The results revealed that 2% sodium alginate concentration produced the highest yield (13.026±0.247 g/l by C. glutamicum and 16.026±0.475 g/l by mixed immobilized culture). Moreover, reusability of immobilized cells was evaluated in 2% concentration with 5 more trials. However, when the number of cycles increased, the production of L-glutamic acid decreased. Conclusion Production of glutamic acid using optimized medium minimizes the time needed for designing the medium composition. It also minimizes external contamination. Glutamic acid production gradually decreased due to multiple uses of beads and consequently it reduces the shelf life. PMID:25215180

Production of L-glutamic Acid with Corynebacterium glutamicum (NCIM 2168) and Pseudomonas reptilivora (NCIM 2598): A Study on Immobilization and Reusability.

PubMed

Shyamkumar, Rajaram; Moorthy, Innasi Muthu Ganesh; Ponmurugan, Karuppiah; Baskar, Rajoo

2014-07-01

L-glutamic acid is one of the major amino acids that is present in a wide variety of foods. It is mainly used as a food additive and flavor enhancer in the form of sodium salt. Corynebacterium glutamicum (C. glutamicum) is one of the major organisms widely used for glutamic acid production. The study was dealing with immobilization of C. glutamicum and mixed culture of C. glutamicum and Pseudomonas reptilivora (P. reptilivora) for L-glutamic acid production using submerged fermentation. 2, 3 and 5% sodium alginate concentrations were used for production and reusability of immobilized cells for 5 more trials. The results revealed that 2% sodium alginate concentration produced the highest yield (13.026±0.247 g/l by C. glutamicum and 16.026±0.475 g/l by mixed immobilized culture). Moreover, reusability of immobilized cells was evaluated in 2% concentration with 5 more trials. However, when the number of cycles increased, the production of L-glutamic acid decreased. Production of glutamic acid using optimized medium minimizes the time needed for designing the medium composition. It also minimizes external contamination. Glutamic acid production gradually decreased due to multiple uses of beads and consequently it reduces the shelf life.

Immobilization of l-Asparaginase on Carrier Materials: A Comprehensive Review.

PubMed

Ulu, Ahmet; Ates, Burhan

2017-06-21

There are two major applications of l-asparaginase (L-ASNase): leukemia therapy and the food industry. Especially, its chemotherapeutic effect has attracted interest from the scientific community and individual scientists. Therefore, to protect the intrinsic activity and half-time of L-ASNase, several carriers and immobilization techniques for immobilization of L-ASNase have been described in articles. Unfortunately, a comprehensive review about immobilization of L-ASNase has not been written until now. In this review, we have thoroughly discussed the carriers for L-ASNase by illustrating immobilization findings including both past and present applications. In addition, we have revealed advantages and disadvantages of immobilized enzyme and related it to free form. We believe that this review will not only provide background information, but also guide future developments.

Genome-wide Association Study Implicates PARD3B-based AIDS Restriction

PubMed Central

Nelson, George W.; Lautenberger, James A.; Chinn, Leslie; McIntosh, Carl; Johnson, Randall C.; Sezgin, Efe; Kessing, Bailey; Malasky, Michael; Hendrickson, Sher L.; Pontius, Joan; Tang, Minzhong; An, Ping; Winkler, Cheryl A.; Limou, Sophie; Le Clerc, Sigrid; Delaneau, Olivier; Zagury, Jean-François; Schuitemaker, Hanneke; van Manen, Daniëlle; Bream, Jay H.; Gomperts, Edward D.; Buchbinder, Susan; Goedert, James J.; Kirk, Gregory D.; O'Brien, Stephen J.

2011-01-01

Background. Host genetic variation influences human immunodeficiency virus (HIV) infection and progression to AIDS. Here we used clinically well-characterized subjects from 5 pretreatment HIV/AIDS cohorts for a genome-wide association study to identify gene associations with rate of AIDS progression. Methods.  European American HIV seroconverters (n = 755) were interrogated for single-nucleotide polymorphisms (SNPs) (n = 700,022) associated with progression to AIDS 1987 (Cox proportional hazards regression analysis, co-dominant model). Results.  Association with slower progression was observed for SNPs in the gene PARD3B. One of these, rs11884476, reached genome-wide significance (relative hazard = 0.3; P =3. 370 × 10−9) after statistical correction for 700,022 SNPs and contributes 4.52% of the overall variance in AIDS progression in this study. Nine of the top-ranked SNPs define a PARD3B haplotype that also displays significant association with progression to AIDS (hazard ratio, 0.3; P = 3.220 × 10−8). One of these SNPs, rs10185378, is a predicted exonic splicing enhancer; significant alteration in the expression profile of PARD3B splicing transcripts was observed in B cell lines with alternate rs10185378 genotypes. This SNP was typed in European cohorts of rapid progressors and was found to be protective for AIDS 1993 definition (odds ratio, 0.43, P = .025). Conclusions. These observations suggest a potential unsuspected pathway of host genetic influence on the dynamics of AIDS progression. PMID:21502085

Immobilization of pectinase from Leucoagaricus gongylophorus on magnetic particles.

PubMed

Adalberto, Paulo Roberto; José dos Santos, Francisco; Golfeto, Camilla Calemi; Costa Iemma, Mônica Rosas; Ferreira de Souza, Dulce Helena; Cass, Quezia Bezerra

2012-10-21

Polygalacturonases (EC 3.2.1.15) hydrolyze the α-1,4-glycosidic linkages in polygalacturonic acid chains. The interest on specific inhibitors of pectinase and the versatility of magnetic support for enzyme immobilization endorsed the preparation of an immobilized enzyme reactor (IMER). This work presents the synthesis of CoFe(2)O(4) amino-derivatives, which was employed as the support for the immobilization of pectinases from Leucoagaricus gongylophorus. Amino-functionalized CoFe(2)O(4) was obtained from glyceryl-derivatized CoFe(2)O(4) and was characterized by infrared spectroscopy and electronic microscopy. The immobilized enzyme maintained the same thermal, chemical and kinetic behaviour of the free enzyme (T(opt) 60 °C; pH(opt) 5.0; K(app)(M) = 0.5 mg min(-1); V(app)(M) ≈ 5.0 μmol min(-1) mL(-1)). The straightforward synthesis of CoFe(2)O(4) derivatives and the efficiency of immobilization offer wide perspectives for the use of the developed new IMER.

Bio-functionalization of electro-synthesized polypyrrole surface by heme enzyme using a mixture of Nafion and glutaraldehyde as synergetic immobilization matrix: Conformational characterization and electrocatalytic studies

NASA Astrophysics Data System (ADS)

ElKaoutit, Mohammed; Naranjo-Rodriguez, Ignacio; Domínguez, Manuel; Hidalgo-Hidalgo-de-Cisneros, José Luis

2011-10-01

Use of a mixture of Nafion and glutaraldehyde as new immobilization matrix was described. The percentage of Nafion was optimized to prevent denaturation of horseradish peroxidase enzyme after its crosslinkage with glutaraldehyde on electro-synthesized polypyrrole surface. Topographic study by Atomic Force Microscopy (AFM) shows that the enzyme seems to have been introduced inside the ionic cluster of Nafion. The characterization of the resulting bio-interfaces by UV-vis and FT-IR shows that the intra-crosslinkage phenomena caused by the use of glutaraldehyde can be eliminated by the optimization of the concentration of Nafion additive. The secondary structure contents of native and immobilized enzyme were analyzed by a Gaussian curve fitting of the respective FT-IR spectra in the amide I region. Immobilized enzyme presented notable increasing percentages of globular and short helical structure compared with native enzyme. This indicates that immobilized enzyme was folded which is in accordance with AFM studies and supports the enzyme entrance inside ionic clutter of Nafion. Thanks to synergic effects of the polypyrrole conducting polymer and the perfluorosulfonic acid polymer Nafion, HRP enzyme was immobilized in its "native" state, the resulting biosensor was able to sense peroxide without any chemical mediator and can be categorized as third generation.

Study of whey fermentation by kefir immobilized on low cost supports using 14C-labelled lactose.

PubMed

Soupioni, Magdalini; Golfinopoulos, Aristidis; Kanellaki, Maria; Koutinas, Athanasios A

2013-10-01

Brewer's Spent Grains (BSG) and Malt Spent Rootlets (MSR) were used as supports for kefir cells immobilization and the role of lactose uptake rate by kefir in the positive activity of produced biocatalysts during whey fermentation was investigated. Lactose uptake rate by the immobilized cells was recorded using (14)C-labelled lactose and the effect of various conditions (pH, temperature and kind of support) on it and consequently on fermentation time and ethanol production was examined. The results showed that lactose uptake rate was correlated to fermentation rate and increased as temperature was increased up to 30°C at pH 5.5. The same results have been recently noticed by using biocatalysts with Delignified Cellulosic Materials (DCM) and Gluten Pellets (GP), but fermentation time of about 7h by kefir immobilized on DCM and BSG resulted to two fold lower than that on GP and MSR. The highest alcohol concentration was observed by MSR. Copyright © 2012 Elsevier Ltd. All rights reserved.

Immobilization Techniques to Avoid Enzyme Loss from Oxidase-Based Biosensors: A One-Year Study

PubMed Central

House, Jody L.; Anderson, Ellen M.; Ward, W. Kenneth

2007-01-01

Background Continuous amperometric sensors that measure glucose or lactate require a stable sensitivity, and glutaraldehyde crosslinking has been used widely to avoid enzyme loss. Nonetheless, little data is published on the effectiveness of enzyme immobilization with glutaraldehyde. Methods A combination of electrochemical testing and spectrophotometric assays was used to study the relationship between enzyme shedding and the fabrication procedure. In addition, we studied the relationship between the glutaraldehyde concentration and sensor performance over a period of one year. Results The enzyme immobilization process by glutaraldehyde crosslinking to glucose oxidase appears to require at least 24-hours at room temperature to reach completion. In addition, excess free glucose oxidase can be removed by soaking sensors in purified water for 20 minutes. Even with the addition of these steps, however, it appears that there is some free glucose oxidase entrapped within the enzyme layer which contributes to a decline in sensitivity over time. Although it reduces the ultimate sensitivity (probably via a change in the enzyme's natural conformation), glutaraldehyde concentration in the enzyme layer can be increased in order to minimize this instability. Conclusions After exposure of oxidase enzymes to glutaraldehyde, effective crosslinking requires a rinse step and a 24-hour incubation step. In order to minimize the loss of sensor sensitivity over time, the glutaraldehyde concentration can be increased. PMID:19888375

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.

Candidacy for bilateral hearing aids: a retrospective multicenter study.

PubMed

Boymans, Monique; Goverts, S Theo; Kramer, Sophia E; Festen, Joost M; Dreschler, Wouter A

2009-02-01

The goal of this study was to find factors for refining candidacy criteria for bilateral hearing aid fittings. Clinical files of 1,000 consecutive hearing aid fittings were analyzed. Case history, audiometric, and rehabilitation data were collected from clinical files, and an extensive questionnaire on long-term outcome measures was conducted. After at least 2 years of hearing aid use, 505 questionnaires were returned. In order to compare differences in benefits between unilateral and bilateral fittings, two subgroups were composed in which most relevant variables (age, degree of hearing loss, and audiometric asymmetry) were matched for unilateral fittings (n=212) and bilateral fittings (n=477). The bilateral group had significantly higher benefit scores than the unilateral group for detection, speech intelligibility in reverberation, and localization, but poorer scores for comfort of loud sounds. The benefit of bilateral hearing aids was not significantly related to the level of technology of the hearing aids. The analysis of the relation between objective parameters and the subjective outcome measures showed that candidacy for a successful bilateral fitting could not be predicted from age, maximum speech intelligibility, employment, exposure to background noise, or social activities.

Site-Selective Orientated Immobilization of Antibodies and Conjugates for Immunodiagnostics Development

PubMed Central

Rusling, James

2016-01-01

Immobilized antibody systems are the key to develop efficient diagnostics and separations tools. In the last decade, developments in the field of biomolecular engineering and crosslinker chemistry have greatly influenced the development of this field. With all these new approaches at our disposal, several new immobilization methods have been created to address the main challenges associated with immobilized antibodies. Few of these challenges that we have discussed in this review are mainly associated to the site-specific immobilization, appropriate orientation, and activity retention. We have discussed the effect of antibody immobilization approaches on the parameters on the performance of an immunoassay. PMID:27876681

Immobilization effects on the photocatalytic activity of CdS quantum Dots-Horseradish peroxidase hybrid nanomaterials.

PubMed

Iñarritu, Iker; Torres, Eduardo; Topete, Antonio; Campos-Terán, José

2017-11-15

The potential use of hybrid nanomaterials based on inorganic optically active nanoparticles known as quantum dots (QDs) and horseradish peroxidase (HRP) has been proposed by several authors as light-controllable nanocatalyzers, moreover, the immobilization within or over silica based supports represents an advantage over bulk-dispersed systems. However, the implications of the immobilization of such hybrid photoactivatable catalyzing systems have not been clarified with detail. Here, we present a thorough study of the functional photoactive efficiency and recycling of immobilized CdS QDs and HRP systems with different configurations, immobilized over silanized silica quartz crystal microbalance (QCM) sensors, allowing an accurate measure of the immobilized mass of each component and its correlation with the initial reaction rate of conversion of Amplex Red (AR) to resorufin. As well, the conversion efficiency is compared between the different systems and also to non-immobilized QD-HRP complexed systems. Copyright © 2017 Elsevier Inc. All rights reserved.

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.

Laser-assisted immobilization of colloid silver nanoparticles on polyethyleneterephthalate

NASA Astrophysics Data System (ADS)

Siegel, Jakub; Lyutakov, Oleksiy; Polívková, Markéta; Staszek, Marek; Hubáček, Tomáš; Švorčík, Václav

2017-10-01

Immobilization of nanoobjects on the surface of underlying material belongs to current issues of material science. Such altered materials exhibits completely exceptional properties exploitable in a broad spectrum of industrially important applications ranging from catalysts up to health-care industry. Here we present unique approach for immobilization of electrochemically synthesized silver nanoparticles on polyethyleneterephthalate (PET) foil whose essence lies in physical incorporation of particles into thin polymer surface layer induced by polarized excimer laser light. Changes in chemical composition and surface structure of polymer after particle immobilization were recorded by wide range of analytical techniques such as ARXPS, EDX, RBS, AAS, Raman, ICP-MS, DLS, UV-vis, SEM, TEM, and AFM. Thorough analysis of both nanoparticles entering the immobilization step as well as modified PET surface allowed revealing the mechanism of immobilization process itself. Silver nanoparticles were physically embedded into a thin surface layer of polymer reaching several nanometers beneath the surface rather than chemically bonded to PET macromolecules. Laser-implanted nanoparticles open up new possibilities especially in the development of the next generation cell-conform antimicrobial coatings of polymeric materials, namely due to the considerable immobilization strength which is strong enough to prevent particle release into the surrounding environment.

Activity and immobilization after eccentric exercise: II. Serum CK.

PubMed

Sayers, S P; Clarkson, P M; Lee, J

2000-09-01

The purpose of the present study was to examine the effect of muscle activity level on serum creatine kinase (CK) activity after high-force eccentric exercise of the elbow flexors. Twenty-six male volunteers were randomly assigned to one of three groups for a 4-d treatment period after exercise: immobilization (N = 9), control (N = 8), and light exercise (N = 9). During the treatment period, the immobilization group had their arm casted and supported in a sling at 90 degrees. The control group had no restriction of their arm activity. The light exercise group performed a daily exercise regimen of 50 biceps curls with a 5-lb dumbbell. Serum CK activity was obtained by venipuncture for three consecutive days before eccentric exercise and during the 4-d treatment period. To quantify activity of the arm, CSA (Computer Science and Applications, Inc.) activity-monitoring devices were worn. Serum CK measurements revealed that there was a significant group by time interaction in the analysis of variance (P < 0.05). Peak serum CK activity of the immobilized group (668 IU) was lower than either the control (4230 IU) or light exercise (2740 IU) group. During the treatment period, activity level among the three groups was significantly different from each other (P < 0.001): 529 counts x min(-1) for the immobilization group, 944 counts x min(-1) for the control group, and 1334 counts x min(-1) for the light exercise group. These results suggest that immobilization of exercised damaged muscle during recovery significantly blunted serum CK activity, which may be due to attenuated removal of CK from the muscle and/or decrease lymphatic transport.

Lipases Immobilization for Effective Synthesis of Biodiesel Starting from Coffee Waste Oils

PubMed Central

Ferrario, Valerio; Veny, Harumi; De Angelis, Elisabetta; Navarini, Luciano; Ebert, Cynthia; Gardossi, Lucia

2013-01-01

Immobilized lipases were applied to the enzymatic conversion of oils from spent coffee ground into biodiesel. Two lipases were selected for the study because of their conformational behavior analysed by Molecular Dynamics (MD) simulations taking into account that immobilization conditions affect conformational behavior of the lipases and ultimately, their efficiency upon immobilization. The enzymatic synthesis of biodiesel was initially carried out on a model substrate (triolein) in order to select the most promising immobilized biocatalysts. The results indicate that oils can be converted quantitatively within hours. The role of the nature of the immobilization support emerged as a key factor affecting reaction rate, most probably because of partition and mass transfer barriers occurring with hydrophilic solid supports. Finally, oil from spent coffee ground was transformed into biodiesel with yields ranging from 55% to 72%. The synthesis is of particular interest in the perspective of developing sustainable processes for the production of bio-fuels from food wastes and renewable materials. The enzymatic synthesis of biodiesel is carried out under mild conditions, with stoichiometric amounts of substrates (oil and methanol) and the removal of free fatty acids is not required. PMID:24970178

Lipases immobilization for effective synthesis of biodiesel starting from coffee waste oils.

PubMed

Ferrario, Valerio; Veny, Harumi; De Angelis, Elisabetta; Navarini, Luciano; Ebert, Cynthia; Gardossi, Lucia

2013-08-13