Sample records for quantitative uv-visible spectroscopy

  1. UV-Visible Spectroscopy

    NSDL National Science Digital Library

    Clark, Jim

    This webpage, part of a larger project "Understanding Chemistry", provides an introduction to UV-visible spectroscopy suitable for use in introductory chemistry and introductory analytical chemistry courses. The pages discuss UV-visible light, absorption, Beer's law, the double-beam spectrometer, and introduce some standard applications of UV-vis spectroscopy.

  2. Moving beyond Traditional UV-Visible Absorption Detection: Cavity Ring-Down Spectroscopy for

    E-print Network

    Zare, Richard N.

    Moving beyond Traditional UV-Visible Absorption Detection: Cavity Ring-Down Spectroscopy for HPLC established for the detection of liquid-phase analytes, cavity- enhanced techniques have recently emerged Parkway, Sunnyvale, California 94085 We describe the use of liquid-phase continuous-wave cavity ring

  3. The Use of UV-Visible Reflectance Spectroscopy as an Objective Tool to Evaluate Pearl Quality

    PubMed Central

    Agatonovic-Kustrin, Snezana; Morton, David W.

    2012-01-01

    Assessing the quality of pearls involves the use of various tools and methods, which are mainly visual and often quite subjective. Pearls are normally classified by origin and are then graded by luster, nacre thickness, surface quality, size, color and shape. The aim of this study was to investigate the capacity of Artificial Neural Networks (ANNs) to classify and estimate the quality of 27 different pearls from their UV-Visible spectra. Due to the opaque nature of pearls, spectroscopy measurements were performed using the Diffuse Reflectance UV-Visible spectroscopy technique. The spectra were acquired at two different locations on each pearl sample in order to assess surface homogeneity. The spectral data (inputs) were smoothed to reduce the noise, fed into ANNs and correlated to the pearl’s quality/grading criteria (outputs). The developed ANNs were successful in predicting pearl type, mollusk growing species, possible luster and color enhancing, donor condition/type, recipient/host color, donor color, pearl luster, pearl color, origin. The results of this study shows that the developed UV-Vis spectroscopy-ANN method could be used as a more objective method of assessing pearl quality (grading) and may become a valuable tool for the pearl grading industry. PMID:22851919

  4. UV-visible spectroscopy method for screening the chemical stability of potential antioxidants for proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Banham, Dustin; Ye, Siyu; Knights, Shanna; Stewart, S. Michael; Wilson, Mahlon; Garzon, Fernando

    2015-05-01

    A novel method based on UV-visible spectroscopy is reported for screening the chemical stability of potential antioxidant additives for proton exchange membrane fuel cells, and the chemical stabilities of three CeOx samples of varying crystallite sizes (6, 13, or 25 nm) are examined. The chemical stabilities predicted by this new screening method are compared to in-situ membrane electrode assembly (MEA) accelerated stress testing, with the results confirming that this rapid and inexpensive method can be used to accurately predict performance impacts of antioxidants.

  5. Kinetic study on bonding reaction of gelatin with CdS nanopaticles by UV-visible spectroscopy.

    PubMed

    Tang, Shihua; Wang, Baiyang; Li, Youqun

    2015-04-15

    The chemical kinetics on gelatin-CdS direct conjugates has been systematically investigated as a function of different temperature and reactant concentration (i.e. Cd(2+), S(2-) and gelatin) by UV-visible spectroscopy, for the first time. The nonlinear fitting and the differential method were used to calculate the initial rate based on the absorbance-time data. A double logarithmic linear equation for calculating the rate constant (k) and the reaction order (n) was introduced. The reaction kinetic parameters (n, k, Ea, and Z) and activation thermodynamic parameters (?G(?), ?H(?), and ?S(?)) were obtained from variable temperature kinetic studies. The overall rate equation allowing evaluation of conditions that provide required reaction rate could be expressed as: r = 1.11 × 10(8) exp(-4971/T)[Cd(2+)][gelatin](0.6)[S(2-)](0.6) (M/S) The calculated values of the reaction rate are well coincide with the experimental results. A suitable kinetic model is also proposed. This work will provide guidance for the rational design of gelatin-directed syntheses of metal sulfide materials, and help to understand the biological effects of nanoparticles at the molecular level. PMID:25668699

  6. In situ characterization of organo-modified and unmodified montmorillonite aqueous suspensions by UV-visible spectroscopy.

    PubMed

    Alin, Jonas; Rubino, Maria; Auras, Rafael

    2015-10-15

    UV-visible (UV-Vis) spectroscopy (Tyndall spectra) was applied and tested for its ability to measure organo-modified and unmodified montmorillonite (MMT) clays in aqueous suspensions. A full factorial design of experiments was used to study the influence of pH, NaCl and clay concentrations on the average particle size of the clay agglomerates. The methodology was evaluated by observing results that were consistent with previous research about the unmodified clay's behavior in aqueous suspensions. The results from this evaluation corresponded to accepted theories about the unmodified clay's behavior, indicating that the methodology is precise enough to distinguish the effects of the studied factors on these clay suspensions. The effect of clay concentration was related to the amount of ions per clay particle for the unmodified clay, but was not significant for the organo-modified MMT. The average particle size of the organo-modified MMT in suspension was significantly larger than that of the unmodified clay. Size of the organo-modified MMT agglomerates in suspension decreased in the presence of NaCl and at both high and low pH; this behavior was opposite to that of the unmodified clay. These results demonstrate that the UV-Vis methodology is well-suited for characterizing clay particle size in aqueous suspensions. The technique also is simple, rapid, and low-cost. PMID:26122795

  7. IN-VIVO DIAGNOSIS OF CHEMICALLY INDUCED MELANOMA IN AN ANIMAL MODEL USING UV-VISIBLE AND NIR ELASTIC SCATTERING SPECTROSCOPY: PRELIMINARY TESTING.

    SciTech Connect

    C. A'AMAR; R. LEY; ET AL

    2001-01-01

    Elastic light scattering spectroscopy (ESS) has the potential to provide spectra that contain both morphological and chromophore information from tissue. We report on a preliminary study of this technique, with the hope of developing a method for diagnosis of highly-pigmented skin lesions, commonly associated with skin cancer. Four opossums were treated with dimethylbenz(a)anthracene to induce both malignant melanoma and benign pigmented lesions. Skin lesions were examined in vivo using both UV-visible and near infrared (NIR) ESS, with wavelength ranges of 330-900 nm and 900-1700 nm, respectively. Both portable systems used identical fiber-optic probe geometry throughout all of the measurements. The core diameters for illuminating and collecting fibers were 400 and 200 {micro}m, respectively, with center-to-center separation of 350 {micro}m. The probe was placed in optical contact with the tissue under investigation. Biopsies from lesions were analyzed by two standard histopathological procedures. Taking into account only the biopsied lesions, UV-visible ESS showed distinct spectral correlation for 11/13 lesions. The NIR-ESS correlated well with 12/13 lesions correctly. The results of these experiments showed that UV-visible and NIR-ESS have the potential to classify benign and malignant skin lesions, with encouraging agreement to that provided by standard histopathological examination. These initial results show potential for ESS based diagnosis of pigmented skin lesions, but further trials are required in order to substantiate the technique.

  8. Oxidation of 2,4-dichlorophenol catalyzed by horseradish peroxidase: characterization of the reaction mechanism by UV-visible spectroscopy and mass spectrometry.

    PubMed

    Laurenti, Enzo; Ghibaudi, Elena; Ardissone, Silvia; Ferrari, Rosa Pia

    2003-06-01

    The hydrogen peroxide-oxidation of 2,4-dichlorophenol catalyzed by horseradish peroxidase has been studied by means of UV-visible spectroscopy and mass spectrometry in order to clarify the reaction mechanism. The dimerization of 2,4-dichlorophenol to 2,4-dichloro-6-(2,4-dichlorophenoxy)-phenol and its subsequent oxidation to 2-chloro-6-(2,4-dichlorophenoxy)-1,4-benzoquinone together with chloride release were observed. The reaction rate was found to be pH-dependent and to be influenced by the pK(a) value of 2,4-dichlorophenol. The dissociation constants of the 2,4-dichlorophenol/horseradish peroxidase (HRP) adduct at pH 5.5 and 8.5 were also determined: their values indicate the unusual stability of the adduct at pH 5.5 with respect to several adducts of HRP with substituted phenols. PMID:12763662

  9. In-vivo diagnosis of chemically induced melanoma in an animal model using UV-visible and NIR elastic-scattering spectroscopy: preliminary testing

    NASA Astrophysics Data System (ADS)

    A'Amar, Ousama M.; Ley, Ronald D.; Ripley, Paul M.; Bigio, Irving J.

    2001-06-01

    Elastic light scattering spectroscopy (ESS) has the potential to provide spectra that contain both morphological and chromophore information from tissue. We report on a preliminary study of this technique, with the hope of developing a method for diagnosis of highly-pigmented skin lesions, commonly associated with skin cancer. Four opossums were treated with dimethylbenz(a)anthracene to induce both malignant melanoma and benign pigmented lesions. Skin lesions were examined in vivo using both UV-visible and near infrared ESS, with wavelength ranges of 330 - 900 nm and 900 - 1700 nm, respectively. Both portable systems used identical fiber-optic probe geometry throughout all of the measurements. The core diameters for illuminating and collecting fibers were 400 and 200 micrometers , respectively, with center-to-center separation of 350 micrometers . The probe was placed in optical contact with the tissue under investigation. Biopsies from lesions were analyzed spectral correlation for 11/13 lesions. The NIR-ESS correlated well with 12/13 lesions correctly.

  10. FT-IR, FT-Raman, UV-Visible, and NMR spectroscopy and vibrational properties of the labdane-type diterpene 13-epi-sclareol

    NASA Astrophysics Data System (ADS)

    Chain, Fernando E.; Leyton, Patricio; Paipa, Carolina; Fortuna, Mario; Brandán, Silvia A.

    2015-03-01

    In this work, FT-IR, FT-Raman, UV-Visible and NMR spectroscopies and density functional theory (DFT) calculations were employed to study the structural and vibrational properties of the labdane-type diterpene 13-epi-sclareol using the hybrid B3LYP method together with the 6-31G? basis set. Three stable structures with minimum energy found on the potential energy curves (PES) were optimized, and the corresponding molecular electrostatic potentials, atomic charges, bond orders, stabilization energies and topological properties were computed at the same approximation level. The complete assignment of the bands observed in the vibrational spectrum of 13-epi-sclareol was performed taking into account the internal symmetry coordinates for the three structures using the scaled quantum mechanical force field (SQMFF) methodology at the same level of theory. In addition, the force constants were calculated and compared with those reported in the literature for similar compounds. The predicted vibrational spectrum and the calculated 1H NMR and 13C NMR chemical shifts are in good agreement with the corresponding experimental results. The theoretical UV-Vis spectra for the most stable structure of 13-epi-sclareol demonstrate a better correlation with the corresponding experimental spectrum. The study of the three conformers by means of the theory of atoms in molecules (AIM) revealed different H bond interactions and a strong dependence of the interactions on the distance between the involved atoms. Furthermore, the natural bond orbital (NBO) calculations showed the characteristics of the electronic delocalization for the two six-membered rings with chair conformations.

  11. FT-IR, FT-Raman, UV-visible, and NMR spectroscopy and vibrational properties of the labdane-type diterpene 13-epi-sclareol.

    PubMed

    Chain, Fernando E; Leyton, Patricio; Paipa, Carolina; Fortuna, Mario; Brandán, Silvia A

    2015-03-01

    In this work, FT-IR, FT-Raman, UV-Visible and NMR spectroscopies and density functional theory (DFT) calculations were employed to study the structural and vibrational properties of the labdane-type diterpene 13-epi-sclareol using the hybrid B3LYP method together with the 6-31G(?) basis set. Three stable structures with minimum energy found on the potential energy curves (PES) were optimized, and the corresponding molecular electrostatic potentials, atomic charges, bond orders, stabilization energies and topological properties were computed at the same approximation level. The complete assignment of the bands observed in the vibrational spectrum of 13-epi-sclareol was performed taking into account the internal symmetry coordinates for the three structures using the scaled quantum mechanical force field (SQMFF) methodology at the same level of theory. In addition, the force constants were calculated and compared with those reported in the literature for similar compounds. The predicted vibrational spectrum and the calculated (1)H NMR and (13)C NMR chemical shifts are in good agreement with the corresponding experimental results. The theoretical UV-Vis spectra for the most stable structure of 13-epi-sclareol demonstrate a better correlation with the corresponding experimental spectrum. The study of the three conformers by means of the theory of atoms in molecules (AIM) revealed different H bond interactions and a strong dependence of the interactions on the distance between the involved atoms. Furthermore, the natural bond orbital (NBO) calculations showed the characteristics of the electronic delocalization for the two six-membered rings with chair conformations. PMID:25498827

  12. Ionization constants and thermal stabilities of uracil and adenine under hydrothermal conditions as measured by in situ UV-visible spectroscopy

    NASA Astrophysics Data System (ADS)

    Balodis, Erik; Madekufamba, Melerin; Trevani, Liliana N.; Tremaine, Peter R.

    2012-09-01

    UV-visible spectra for aqueous uracil and adenine were measured in a high-pressure platinum flow cell with sapphire windows at temperatures up to 250 °C at a constant pressure of 7.2 MPa. Ionization constants were determined from pH-dependent spectra in the buffer solutions NH3/NH4Cl, NaHCO3/Na2CO3, HCOOH/NaHCOO and NaH2PO4/Na2HPO4. Variations in the spectra with pH and temperature at constant flow rate were used to determine the first ionization constant of uracil, K1a (uracil), and the first and second acid ionization constants of adenine, K1a (adenine) and K2a (adenine), at ionic strength I = 0.2 mol kg-1 and temperatures up to 200 °C. Time-dependent spectra, obtained by operating the cell as a stopped flow reactor, were used to examine the rate of thermal decomposition as a function of temperature and pH from 200 to 250 °C. Reaction pathways and rate constants were determined by singular value decomposition methods. Uracil and adenine decomposition occurred by one-step and two-step processes, respectively. The kinetic results in the NaH2PO4/Na2HPO4 buffer solution are in quantitative agreement with the less-extensive pioneering study by White (Nature 310, 430-432 (1984)), but differ from results in buffers that do not contain phosphate, suggesting that phosphate enhances the thermal stability of nucleic acid bases.

  13. Real-Time UV-Visible Spectroscopy Analysis of Purple Membrane-Polyacrylamide Film Formation Taking into Account Fano Line Shapes and Scattering

    PubMed Central

    Gomariz, María; Blaya, Salvador; Acebal, Pablo; Carretero, Luis

    2014-01-01

    We theoretically and experimentally analyze the formation of thick Purple Membrane (PM) polyacrylamide (PA) films by means of optical spectroscopy by considering the absorption of bacteriorhodopsin and scattering. We have applied semiclassical quantum mechanical techniques for the calculation of absorption spectra by taking into account the Fano effects on the ground state of bacteriorhodopsin. A model of the formation of PM-polyacrylamide films has been proposed based on the growth of polymeric chains around purple membrane. Experimentally, the temporal evolution of the polymerization process of acrylamide has been studied as function of the pH solution, obtaining a good correspondence to the proposed model. Thus, due to the formation of intermediate bacteriorhodopsin-doped nanogel, by controlling the polymerization process, an alternative methodology for the synthesis of bacteriorhodopsin-doped nanogels can be provided. PMID:25329473

  14. Quantitative monitoring of an activated sludge reactor using on-line UV-visible and near-infrared spectroscopy

    Microsoft Academic Search

    Mafalda C. Sarraguça; Ana Paulo; Madalena M. Alves; Ana M. A. Dias; João A. Lopes; Eugénio C. Ferreira

    2009-01-01

    The performance of an activated sludge reactor can be significantly enhanced through use of continuous and real-time process-state\\u000a monitoring, which avoids the need to sample for off-line analysis and to use chemicals. Despite the complexity associated\\u000a with wastewater treatment systems, spectroscopic methods coupled with chemometric tools have been shown to be powerful tools\\u000a for bioprocess monitoring and control. Once implemented

  15. Portable UV-visible spectrometer for measuring absorbance and dichroism of Langmuir monolayers at air-water interfaces.

    NASA Astrophysics Data System (ADS)

    Tronin, Andrey; Strzalka, Joseph; Krishnan, Venkata; Kuzmenko, Ivan; Fry, H. Christopher; Therien, Michael; Blasie, J. Kent

    2009-03-01

    An UV-visible spectrometer for measuring absorbance and dichroism of Langmuir monolayers under in situ conditions is described. The spectrometer utilizes a stand-alone multipass sensor, which is placed in a Langmuir trough and coupled with light source and spectrometer head via fiber optics. Implementation of the multipass scheme in the absorbance sensor makes it possible to obtain reliable quantitative spectroscopic data of the Langmuir monolayers with absorbance as low as 1 mOD. Such high sensitivity makes the developed sensor very useful for UV-visible spectral studies of a wide variety of chromophores. The new technique was applied to several model systems: fatty acid monolayers containing amphiphilic dyes DiI or BODIPY and also a monolayer of a synthetic amphiphilic porphyrin-binding peptide BBC16. Implementation of UV-visible absorbance spectroscopy measurements in situ together with x-ray scattering technique was used to confirm the bound state of the chromophore, and determine the exact position of the latter in the peptide matrix. Fiber optics design of the spectrometer provides portability and compatibility with other experimental techniques making it possible to study samples with a geometry unsuitable for conventional spectroscopic measurements and located in experimental environments with spatial limitations, such as synchrotron x-ray scattering stations.

  16. UV/Visible Telescope with Hubble Disposal

    NASA Technical Reports Server (NTRS)

    Benford, Dominic J.

    2013-01-01

    Submission Overview: Our primary objective is to convey a sense of the significant advances possible in astrophysics investigations for major Cosmic Origins COR program goals with a 2.4m telescope asset outfitted with one or more advanced UV visible instruments. Several compelling science objectives were identified based on community meetings these science objectives drove the conceptual design of instruments studied by the COR Program Office during July September 2012. This RFI submission encapsulates the results of that study, and suggests that a more detailed look into the instrument suite should be conducted to prove viability and affordability to support the demonstrated scientific value. This study was conducted in the context of a larger effort to consider the options available for a mission to dispose safely of Hubble hence, the overall architecture considered for the mission we studied for the 2.4m telescope asset included resource sharing. This mitigates combined cost and risk and provides naturally for a continued US leadership role in astrophysics with an advanced, general-purpose UV visible space telescope.

  17. Microsystems for UV-visible and x-ray analysis of protein crystals

    Microsoft Academic Search

    L. S. L. Cheung; R. Quick; S. K. Singh; A. Weichsel; W. R. Montfort; Y. Zohar

    2007-01-01

    polydimethylsiloxane (PDMS) based microsystems have successfully been fabricated and characterized for studying protein crystals utilizing both UV-visible spectroscopy and X-ray crystallography. Transmittance tests have been conducted with PDMS and glass substrates; the measurements indicate that in PDMS, unlike glass, the emerging intensity is higher than 50% of the incident intensity as long as the total optical path is shorter than

  18. Total ozone measured during EASOE by a UV-visible spectrometer which observes stars

    Microsoft Academic Search

    D. J. Fish; R. L. Jones; R. A. Freshwater; H. K. Roscoe; D. J. Oldham; J. E. Harries

    1994-01-01

    Total ozone was measured from Abisko, Sweden (68.4°N, 18.8°E) from January to early March 1992, by a new instrument which uses stars and the Moon as sources of UV-visible light for absorption spectroscopy. In addition, some zenith-sky observations were made. Ozone measurements obtained using both techniques are presented and compared with those from other instruments. Good agreement with simultaneous ozonesonde

  19. Quantification of UV-Visible and Laser Spectroscopic Techniques for Materials Accountability and Process Control

    SciTech Connect

    Czerwinski, Kenneth

    2013-09-13

    Ultraviolet–visible spectroscopy (UV–Visible) and time-resolved laser fluorescence spectroscopy (TRLFS) optical techniques can permit on-line analysis of actinide elements in a solvent extraction process in real time. These techniques have been used for measuring actinide speciation and concentration under laboratory conditions and are easily adaptable to multiple sampling geometries, such as dip probes, fiber-optic sample cells, and flow-through cell geometries. To fully exploit these techniques, researchers must determine the fundamental speciation of target actinides and the resulting influence on spectroscopic properties. Detection limits, process conditions, and speciation of key actinide components can be established and utilized in a range of areas, particularly those related to materials accountability and process control. Through this project, researchers will develop tools and spectroscopic techniques to evaluate solution extraction conditions and concentrations of U, Pu, and Cm in extraction processes, addressing areas of process control and materials accountability. The team will evaluate UVVisible and TRLFS for use in solvent extraction-based separations. Ongoing research is examining efficacy of UV-Visible spectroscopy to evaluate uranium and plutonium speciation under conditions found in the UREX process and using TRLFS to evaluate Cm speciation and concentration in the TALSPEAK process. A uranyl and plutonium nitrate UV–Visible spectroscopy study met with success, which supports the utility and continued exploration of spectroscopic methods for evaluation of actinide concentrations and solution conditions for other aspects of the UREX+ solvent extraction scheme. This project will ex examine U and Pu absorbance in TRUEX and TALSPEAK, perform detailed examination of Cm in TRUEX and TALSPEAK, study U laser fluorescence, and apply project data to contactors. The team will also determine peak ratios as a function of solution concentrations for the UV-Visible spectroscopy studies. The use of TRLFS to examine Cm and U will provide data to evaluate lifetime, peak location, and peak ratios (mainly for U). The bases for the spectroscopic techniques have been investigated, providing fundamental evidence for the application’s utility.

  20. Studies on the uv- visible and photoluminescent emission in nanocrystalline tungsten oxide

    NASA Astrophysics Data System (ADS)

    Veenas, C. L.; Asitha, L. R.; Bose, Vipin C.; Aiswarya Raj, A. S.; Madhu, G.; Biju, V.

    2015-02-01

    Nanocrystalline Tungsten Oxide (WO3) samples having different average crystallite sizes 10nm, 11 nm, 22 nm and 26 nm were synthesized through controlled chemical precipitation method. The phase purity and average crystallite sizes were estimated from X-ray Diffraction (XRD) analysis. The vibrational characteristics of the samples were studied by Raman spectroscopy. The X-ray Photoelectron Spectroscopic (XPS) analysis of the samples revealed the presence of oxygen vacancies which was confirmed by the uv-visible (uv- vis) absorption and photoluminescence (PL) emission studies.

  1. Feasibility study of extemporaneous control of cytotoxic preparations: tests with an innovating spectrometer coupling UV\\/visible and IR detections

    Microsoft Academic Search

    Natacha Ripoche; Pierre Baumgartner; Christelle Audeval; Sophie Rochard

    Background: In the context of good manufacturing practice, our production unit wanted to develop an analytical con- trol of the 22,000 chemotherapy treatments prepared per year. Our objective was a quantitative, extemporaneous and qualitative check of this proposal. Methods: The spectrophotometer used was innovating because of its double detection: in ultra-violet (UV)\\/visible (200- 580 nm) and average infra-red (IR) (950-3,100

  2. UV/visible camera for the Clementine mission

    SciTech Connect

    Kordas, J.F.; Lewis, I.T.; Priest, R.E. [and others

    1995-04-01

    This article describes the Clementine UV/Visible (UV/Vis) multispectral camera, discusses design goals and preliminary estimates of on-orbit performance, and summarizes lessons learned in building and using the sensor. While the primary objective of the Clementine Program was to qualify a suite of 6 light-weight, low power imagers for future Department of Defense flights, the mission also has provided the first systematic mapping of the complete lunar surface in the visible and near-infrared spectral regions. The 410 g, 4.65 W UV/Vis camera uses a 384 x 288 frame-transfer silicon CCD FPA and operates at 6 user-selectable wavelength bands between 0.4 and 1.1 {micro}m. It has yielded lunar imagery and mineralogy data with up to 120 in spatial resolution (band dependent) at 400 km periselene along a 39 km cross-track swath.

  3. Cloud identification in the Canadian High Arctic using the UV-visible colour index

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaoyi; Adams, Cristen; Strong, Kimberly; Duck, Thomas; Perro, Chris; Hudak, David; Rodriguez, Peter

    2014-05-01

    In UV-visible spectroscopy, Rayleigh and Mie scattering contribute to the broadband extinction seen in spectra of scattered sunlight. The relative intensity of these two components of scattering is highly dependent on the cloud condition of the sky. The colour index, defined as the ratio of light intensities at different wavelengths, typically 350 nm and 550 nm, provides a means of determining the cloud conditions. A UV-visible triple-grating spectrometer, the UT-GBS (University of Toronto Ground-Based Spectrometer), was installed at the Polar Environment Atmospheric Research Laboratory (PEARL), at Eureka in the Canadian High Arctic (86.4°W, 80.1°N) in 1999. Since then, the instrument has made daily measurements during spring from 1999-2009, and year-round, with the exception of polar night, from 2010-2013. The UT-GBS measures vertical column densities of ozone, NO2, and BrO, as well as slant column densities of enhanced OClO, by using the Differential Optical Absorption Spectroscopy (DOAS) technique. We use the colour index data from the UT-GBS to distinguish polar stratospheric clouds and tropospheric clouds. The UV-visible measurements are supplemented by vertically resolved lidar and radar cloud data products. The CANDAC (Canadian Network for the Detection of Atmospheric Change) Rayleigh-Mie-Raman Lidar (CRL) and the Millimetre Cloud Radar (MMCR) are located at the Zero Altitude PEARL Auxiliary Laboratory (0PAL), which is about 15 km away from PEARL. The CRL uses ultra-short pulses of light from two lasers, operating at ultraviolet (355 nm) and visible (532 nm) wavelengths. The CRL measures the vertical distribution of aerosols, temperature, and water vapour in the troposphere and lower stratosphere. The zenith-pointing MMCR measures equivalent radar reflectivity, Doppler velocity, spectral width, and Doppler spectra, from which information about cloud heights, thicknesses, internal structure and vertical motions can be determined. Polar stratospheric cloud (PSC) events have been observed during spring by the UT-GBS and the CRL; these will be discussed in the context of the location of the polar vortex relative to Eureka, stratospheric temperatures, and stratospheric ozone loss events. In addition to detecting PSCs, the colour index can be used for the detection of tropospheric clouds. The UT-GBS cloud index results are in good agreement with data from the MMCR. Thus the cloud index can be useful for assessing the quality of DOAS retrievals, which can be greatly affected by tropospheric clouds.

  4. UV-visible sensors based on polymorphous silicon

    NASA Astrophysics Data System (ADS)

    Guedj, Cyril S.; Cabarrocas, Pere R. i.; Massoni, Nicolas; Moussy, Norbert; Morel, Damien; Tchakarov, Svetoslav; Bonnassieux, Yvan

    2003-09-01

    UV-based imaging systems can be used for low-altitude rockets detection or biological agents identification (for instance weapons containing ANTHRAX). Compared to conventional CCD technology, CMOS-based active pixel sensors provide several advantages, including excellent electro-optical performances, high integration, low voltage operation, low power consumption, low cost, long lifetime, and robustness against environment. The monolithic integration of UV, visible and infrared detectors on the same uncooled CMOS smart system would therefore represent a major advance in the combat field, for characterization and representation of targets and backgrounds. In this approach, we have recently developped a novel technology using polymorphous silicon. This new material, fully compatible with above-IC silicon technology, is made of nanometric size ordered domains embedded in an amorphous matrix. The typical quantum efficiency of detectors made of this nano-material reach up to 80 % at 550 nm and 30 % in the UV range, depending of the design and the growth parameters. Furthermore, a record dark current of 20 pA/cm2 at -3 V has been reached. In addition, this new generation of sensors is significantly faster and more stable than their amorphous silicon counterparts. In this paper, we will present the relationship between the sensor technology and the overall performances.

  5. Monitoring of Laser Material Welding Process Using UV-Visible Spectrometer

    SciTech Connect

    Genc, B.; Kacar, E.; Akman, E.; Demir, A. [University of Kocaeli, Laser Technologies Research and Application Center, Kocaeli (Turkey)

    2007-04-23

    UV-Visible spectrometer is used to record emission from magnesium and titanium metal plates during laser welding processing. Geometrically corrected Czerny-Turner configurations nearly eliminate defocusing problem. The Optikwerks software is used to find the optimum Czerny-Turner configuration and to choose optical elements such as grating types, mirrors focal length and diameter, and slit width. The design parameters of the uv-visible spectrometer in the wavelength range 200-1100 nm for monitoring laser material welding processing.

  6. Application of infrared and UV-visible remote sensing techniques for studying the stratosphere and for estimating anthrophogenic emissions

    Microsoft Academic Search

    Johan Magnus Mellqvist

    1999-01-01

    Infrared and UV\\/visible broadband absorption techniques have been used in three applications related to environmental research and atmospheric science. The techniques are based on measuring the attenuation of light by the atmosphere in the infrared and UV\\/visible region, and since a very large number of species absorb light in these wavelength regions, the techniques studied allow the measurement of several

  7. Aprotic solvents effect on the UV-visible absorption spectra of bixin

    NASA Astrophysics Data System (ADS)

    Rahmalia, Winda; Fabre, Jean-François; Usman, Thamrin; Mouloungui, Zéphirin

    2014-10-01

    We describe here the effects of aprotic solvents on the spectroscopic characteristics of bixin. Bixin was dissolved in dimethyl sulfoxide, acetone, dichloromethane, ethyl acetate, chloroform, dimethyl carbonate, cyclohexane and hexane, separately, and its spectra in the resulting solutions were determined by UV-visible spectrophotometry at normal pressure and room temperature. We analyzed the effect of aprotic solvents on ?max according to Onsager cavity model and Hansen theory, and determined the approximate absorption coefficient with the Beer-Lambert law. We found that the UV-visible absorption spectra of bixin were found to be solvent dependent. The S0 ? S2 transition energy of bixin in solution was dependent principally on the refractive index of the solvents and the bixin-solvent dispersion interaction. There was a small influence of the solvents dielectric constant, permanent dipole interaction and hydrogen bonding occurred between bixin and solvents. The absorbance of bixin in various solvents, with the exception of hexane, increased linearly with concentration.

  8. Piezo-phototronic UV/visible photosensing with optical-fiber-nanowire hybridized structures.

    PubMed

    Wang, Zhaona; Yu, Ruomeng; Pan, Caofeng; Liu, Ying; Ding, Yong; Wang, Zhong Lin

    2015-03-01

    An optical-fiber-nanowire hybridized UV-visible photodetector (PD) is reported. The PD is designed to allow direct integration in optical communication systems without requiring the use of couplers via fiber-welding technology. The PD works in two modes: axial and off-axial illumination mode. By using the piezo-phototronic effect, the performance of the PD is enhanced/optimized by up to 718% in sensitivity and 2067% in photoresponsivity. PMID:25589428

  9. A star-pointing UV-visible spectrometer for remote sensing of the stratosphere

    Microsoft Academic Search

    H. K. Roscoe; R. L. Jones; R. A. Freshwater; D. J. Fish; R. Wolfenden; J. E. Harries; D. J. Oldham

    1993-01-01

    Significant ozone loss due to reactive chlorine from man-made chemicals has occurred near the poles in the last decade. In this paper, we describe a novel star-pointing UV-visible spectrometer to measure amounts of some reactive gases in the ozone layer and discuss its advantages. The instrument has the capability of measuring stratospheric amounts of O3, NO2, NO3 and OClO at

  10. Quantitative Spectroscopy of BA-type Supergiants

    E-print Network

    N. Przybilla; K. Butler; S. R. Becker; R. P. Kudritzki

    2005-09-22

    Luminous BA-SGs allow topics ranging from NLTE physics and the evolution of massive stars to the chemical evolution of galaxies and cosmology to be addressed. A hybrid NLTE technique for the quantitative spectroscopy of BA-SGs is discussed. Thorough tests and first applications of the spectrum synthesis method are presented for four bright Galactic objects. Stellar parameters are derived from spectroscopic indicators. The internal accuracy of the method allows the 1sigma-uncertainties to be reduced to BA-SGs as versatile tools for extragalactic stellar astronomy beyond the Local Group. (abridged)

  11. Analysis the UV-visible Spectra of Neuroglobin Based on Two-Level Model

    NASA Astrophysics Data System (ADS)

    Thao, T. T.; Anh, C. T.; Lan, N. T.; Viet, N. A.

    2015-06-01

    Neuroglobin (Ngb), a novel member of the Globin Group, is recently discovered by Burmester et al. (2000). Its uncertain physiological function makes lots of interest. The existing of a six-coordination heme geometry with proximal and distal histidines directly creates an axis within the heme iron, while the sixth ligand coordination binds to small ligand reversibly. The analysis of UV-visible spectrum of Ngb by the well-known two-level model shows an agreement of the experiment data and theoretical results.

  12. Aprotic solvents effect on the UV-visible absorption spectra of bixin.

    PubMed

    Rahmalia, Winda; Fabre, Jean-François; Usman, Thamrin; Mouloungui, Zéphirin

    2014-10-15

    We describe here the effects of aprotic solvents on the spectroscopic characteristics of bixin. Bixin was dissolved in dimethyl sulfoxide, acetone, dichloromethane, ethyl acetate, chloroform, dimethyl carbonate, cyclohexane and hexane, separately, and its spectra in the resulting solutions were determined by UV-visible spectrophotometry at normal pressure and room temperature. We analyzed the effect of aprotic solvents on ?max according to Onsager cavity model and Hansen theory, and determined the approximate absorption coefficient with the Beer-Lambert law. We found that the UV-visible absorption spectra of bixin were found to be solvent dependent. The S0?S2 transition energy of bixin in solution was dependent principally on the refractive index of the solvents and the bixin-solvent dispersion interaction. There was a small influence of the solvents dielectric constant, permanent dipole interaction and hydrogen bonding occurred between bixin and solvents. The absorbance of bixin in various solvents, with the exception of hexane, increased linearly with concentration. PMID:24840486

  13. Light, Molecules, Action: Broadband UV-visible transient absorption studies of excited state dynamics in photoactive molecules

    NASA Astrophysics Data System (ADS)

    Sension, Roseanne

    2015-03-01

    Broadband UV-visible transient absorption spectroscopy provides a powerful tool for the investigation of the dynamics of electronically excited molecules in the condensed phase. It is now possible to obtain transient spectra on a routine basis spanning the range from <300 nm to >800 nm with femtosecond time resolution. We have used this method to study the excited state dynamics and internal conversion of a range of molecular systems with potential application as optically powered molecular devices. The cyclohexadiene ring-opening reaction is the basis of a class of important optical switches and of the biological synthesis of previtamin D3. The ring-opening reaction is ultrafast, occurring on a picosecond to subpicosecond times scale depending on the substituents around the ring. These have a significant influence on the dynamics and electronic structure of the electronically excited molecule. The results of a series of transient absorption studies as a function of chromophore substitution and environment will be presented. The cis-trans isomerization of polyene molecules, especially substituted stilbenes, provides another important class of functional molecular transformations. Again the excited state dynamics can be ultrafast with photochemistry controlled by details of the curve crossings and conical intersections. Finally the photochemistry of the even more complex set of cobalamin chromophores with a photoalabile C-Co bond has been proposed as a tool for spatio-temporal control of molecule delivery including drug delivery. Broadband transient absorption spectroscopy has been used to investigate the ultrafast electronic dynamics of a range of cobalamin compounds with comparison to detailed theoretical calculations. The results of these studies will be presented.

  14. UV-visible luminescence properties of the broad-band Yb:CALGO laser crystal

    NASA Astrophysics Data System (ADS)

    Jaffres, A.; Sharma, S. K.; Loiseau, P.; Viana, B.; Doualan, J. L.; Moncorgé, R.

    2015-03-01

    Yb:CALGO is now recognized to exhibit outstanding properties for the production of high-power and ultra-short laser pulses in the near infrared spectral range. However, various UV-visible absorption bands can be also observed due to different types of charge transfer mechanisms. Some of them are assigned to the formation of color centers due to small polarons and others to O2-?Yb3+ ligand-to-metal charge transfer (LMCT) transitions. The former can be removed by using adequate thermal treatments. The latter are intrinsic and they are very intense with cross sections of about two orders of magnitude larger that the near infrared ones. In fact, such LMCT absorption bands are responsible for relatively large changes of ionic polarizabilities and to non-negligible pseudo-nonlinear changes of refractive indices which should certainly affect the laser properties of Yb:CALGO at high pump power levels.

  15. Forensic discrimination of dyed hair color: I. UV-visible microspectrophotometry.

    PubMed

    Barrett, Julie A; Siegel, Jay A; Goodpaster, John V

    2010-03-01

    Current protocols for examining hair do not attempt to differentiate hair color using instrumental analysis. In this study, hair samples treated with 55 different red hair dyes were analyzed using UV-visible microspectrophotometry between 200 and 700 nm. Using air as a background reference gave the best results, although mounting media such as glycerin could also be used. The contribution of the hair substrate is predominantly observed in the range of 300-400 nm while the dye peak is evident in the range of 425-550 nm. It was found that the presence of hair dye reduces the overall intrasample variability of the hair color. In addition, visual inspection and spectral interpretation showed that dyed hair exhibits distinct and discernable shades. The color of all samples was stable during storage and while all hair dyes fade with washing, significant fading of the color was only evident after daily washing for 3 weeks. PMID:20141558

  16. UV, visible, and near-IR reflectivity data for magnetic soils/rocks from Brazil

    NASA Technical Reports Server (NTRS)

    Vempati, R. K.; Morris, R. V.; Lauer, H. V., Jr.; Coey, J. M. D.

    1991-01-01

    The objective is to obtain UV, visible, and near-IR reflectivity spectra for several magnetic Brazilian soils/rocks and compare them to corresponding data for Mars to see if these materials satisfy both magnetic and spectral constraints for Mars. Selected physical properties of the magnetic Brazilian soils/rocks are presented. In general, the spectral features resulting from ferric crystal-field transitions are much better defined in the spectra of the magnetic Brazilian soils/rocks than in Martian spectral data. Presumably, this results from a relatively higher proportion of crystalline ferric oxides for the former. The apparent masking of the spectral signature of maghemite by hematite or goethite for the Brazilian samples implies the magnetic and spectral constraints for Mars can be decoupled. That is, maghemite may be present in magnetically-significant but optically-insignificant amounts compared to crystalline hematite.

  17. Exploration of Thermochromic Materials Using Experimental and Theoretical Infrared and UV-Visible Spectroscopy

    ERIC Educational Resources Information Center

    Costello, Kelsey; Doan, Kevin Thinh; Organtini, Kari Lynn; Wilson, John; Boyer, Morgan; Gibbs, Greglynn; Tribe, Lorena

    2014-01-01

    This laboratory was developed by undergraduate students in collaboration with the course instructor as part of a peer-developed and peer-led lab curriculum in a general chemistry course. The goal was to explore the hypothesis that crystal violet lactone was responsible for the thermochromic properties of a sipping straw using a FT-IR for…

  18. Infrared quantitative spectroscopy and planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Flaud, J.-M.

    2009-04-01

    Optical measurements of atmospheric minor constituents are carried out using spectrometers working in the UV-visible, infrared and microwave spectral ranges. In all cases the quality of the analysis and of the interpretation of the atmospheric spectra requires the best possible knowledge of the molecular parameters of the species of interest. To illustrate this point we will concentrate on recent laboratory studies of nitric acid, chlorine nitrate and formaldehyde. Nitric acid is one of the important minor constituent of the terrestrial atmosphere. Using new and accurate experimental results concerning the spectroscopic properties of the H14NO3 and H15NO3 molecules, as well as improved theoretical methods (Perrin et al., 2004), it has been possible to generate an improved set of line parameters for these molecules in the 11.2 ?m spectral region. These line parameters were used to detect for the first time the H15NO3 molecule in the atmosphere analyzing atmospheric spectra recorded by the MIPAS experiment. The retrievals of chlorine nitrate profiles are usually performed using absorption cross sections (Birk and Wagner, 2003). Following a high resolution analysis of the ?3 and ?4bands of this species in the 12.8 ?m region wepropose, as a possibility, to use line by line calculation simulating its ?4Q-branch for the atmospheric temperature and pressure ranges. For the measurement of atmospheric formaldehyde concentrations, mid-infrared and ultraviolet absorptions are both used by ground, air or satellite instruments. It is then of the utmost importance to have consistent spectral parameters in these various spectral domains. Consequently the aim of the study performed at LISA (Gratien et al., 2007) was to intercalibrate formaldehyde spectra in the infrared and ultraviolet regions acquiring simultaneously UV and IR spectra using a common optical cell. The results of the work will be presented. Also high resolution infrared data derived from Perrin et al., 2003 have been used to determine vertical distributions from the upper troposphere to the stratopause using the high spectral resolution measurements of MIPAS (Steck et al., 2008). References: M. Birk, G. Wagner, J. Quant. Spectros. Radiat.Transfer, 82, 443, 2003. G. Brizzi, M. Carlotti, J.-M. Flaud, A. Perrin and M. Ridolfi, Geophys. Res. Lett., 34, L03802, 2006. A. Gratien, B. Picquet-Varrault, J. Orphal, E. Perraudin, J.-F. Doussin and J.-M. Flaud, J. Geophys. Res., 112, D05305, 2007. A. Perrin, F. Keller and J.-M. Flaud, J. Mol. Spectrosc., 221, 192, 2003. A. Perrin, J. Orphal, J.-M. Flaud, S. Klee, G. Mellau, H. Mader, D. Walbrodt and M. Winnewisser, J. Mol. Spectrosc, 228, 375, 2004. T. Steck, N. Glatthor, T. von Clarmann, H. Fischer, J. M. Flaud, B. Funke, U. Grabowski, M. Hopfner, S. Kellmann, A. Linden, A. Perrin, and G. P. Stiller, Atm. Chem. Phys., 8, 463, 2008.

  19. Journal of Quantitative Spectroscopy & Radiative Transfer 98 (2006) 189201

    E-print Network

    Guo, Zhixiong "James"

    2006-01-01

    Journal of Quantitative Spectroscopy & Radiative Transfer 98 (2006) 189­201 Correlative studies vessel parameters such as the location, size, and hemoglobin concentration of the CCA or jugular vein (JV wavelengths; Radiative transfer; Cerebral blood oxygenation; Correlations; MC simulation; Noninvasive

  20. CONFOCAL MICROSCOPY SYSTEM PERFORMANCE: QA TESTS, QUANTITATION AND SPECTROSCOPY

    EPA Science Inventory

    Confocal Microscopy System Performance: QA tests, Quantitation and Spectroscopy. Robert M. Zucker 1 and Jeremy M. Lerner 2, 1Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research Development, U.S. Environmen...

  1. Scientific Objectives for UV-Visible Astrophysics Investigations: A Summary of Responses by the Community (2012)

    NASA Technical Reports Server (NTRS)

    Scowen, Paul A.; Perez, Mario R.; Neff, Susan G.; Benford, Dominic J.

    2014-01-01

    Following several recommendations presented by the Astrophysics Decadal Survey 2010 centered around the need to define "a future ultraviolet-optical space capability," on 2012 May 25, NASA issued a Request for Information (RFI) seeking persuasive ultraviolet (UV) and visible wavelength astrophysics science investigations. The goal was to develop a cohesive and compelling set of science objectives that motivate and support the development of the next generation of ultraviolet/visible space astrophysics missions. Responses were due on 10 August 2012 when 34 submissions were received addressing a number of potential science drivers. A UV/visible Mission RFI Workshop was held on 2012 September 20 where each of these submissions was summarized and discussed in the context of each other. We present a scientific analysis of these submissions and presentations and the pursuant measurement capability needs, which could influence ultraviolet/visible technology development plans for the rest of this decade. We also describe the process and requirements leading to the inception of this community RFI, subsequent workshop and the expected evolution of these ideas and concepts for the remainder of this decade.

  2. Scientific Objectives for UV-Visible Astrophysics Investigations: A Summary of Responses by the Community (2012)

    NASA Technical Reports Server (NTRS)

    Scowen, Paul A.; Perez, Mario R.; Neff, Susan G.; Bedford, Dominic J.

    2013-01-01

    Following several recommendations presented by the Astrophysics Decadal Survey 2010 centered around the need to define "a future ultraviolet-optical space capability," on 2012 May 25, NASA issued a Request for Information (RFI) seeking persuasive ultraviolet (UV) and visible wavelength astrophysics science investigations. The goal was to develop a cohesive and compelling set of science objectives that motivate and support the development of the next generation of ultraviolet/visible space astrophysics missions. Responses were due on 10 August 2012 when 34 submissions were received addressing a number of potential science drivers. A UV/visible Mission RFI Workshop was held on 2012 September 20 where each of these submissions was summarized and discussed in the context of each other. We present a scientific analysis of these submissions and presentations and the pursuant measurement capability needs, which could influence ultraviolet/visible technology development plans for the rest of this decade. We also describe the process and requirements leading to the inception of this community RFI, subsequent workshop and the expected evolution of these ideas and concepts for the remainder of this decade.

  3. UV-Visible Spectroscopic Method and Models for Assessment and Monitoring of Harmful Algal Blooms

    NASA Technical Reports Server (NTRS)

    Mitchell, B. Greg

    2000-01-01

    The development of an enhanced predictive and early warning capability for the occurrence and impact of harmful algal blooms (HABs) would be of great benefit to coastal communities. A critical issue for early detection and monitoring of HABs is the need to detect harmful algal species within a mixed-species phytoplankton assemblage. Possession of UV-absorbing compounds called mycosporine-like amino acids (MAAs) may be one factor that allows HAB species to out-compete their phytoplankton neighbors. Possession of MAAs, which we believe can be inferred from strong UV-absorption signals in phytoplankton absorption coefficients, can be used as a flag for potential HAB outbreak. The goal of this project was to develop a solar simulating UV-visible incubator to grow HAB dinoflagellates, to begin MAA analysis of samples collected on global cruises, and to carry out initial experiments on HAB dinoflagellate species in pure culture. Our scientific objectives are to quantify MAA production and spectral induction mechanisms in HAB species, to characterize spectral absorption of MAAs, and to define the ecological benefit of MAAs (i.e. photoprotection). Data collected on cruises to the global oceans will be used to parameterize phytoplankton absorption in the UV region, and this parameterization could be incorporated into existing models of seawater optical properties in the UV spectral region. Data collected in this project were used for graduate fellowship applications by Elizabeth Frame. She has been awarded an EPA STAR fellowship to continue the work initiated by this project.

  4. Development of a broadband picosecond infrared spectrometer and its incorporation into an existing ultrafast time-resolved resonance Raman, UV/visible, and fluorescence spectroscopic apparatus.

    PubMed

    Towrie, Michael; Grills, David C; Dyer, Joanne; Weinstein, Julia A; Matousek, Pavel; Barton, Robin; Bailey, Philip D; Subramaniam, Naresh; Kwok, Wai M; Ma, Chensheng; Phillips, David; Parker, Anthony W; George, Michael W

    2003-04-01

    We have constructed a broadband ultrafast time-resolved infrared (TRIR) spectrometer and incorporated it into our existing time-resolved spectroscopy apparatus, thus creating a single instrument capable of performing the complementary techniques of femto-/picosecond time-resolved resonance Raman (TR3), fluorescence, and UV/visible/infrared transient absorption spectroscopy. The TRIR spectrometer employs broadband (150 fs, approximately 150 cm(-1) FWHM) mid-infrared probe and reference pulses (generated by difference frequency mixing of near-infrared pulses in type I AgGaS2), which are dispersed over two 64-element linear infrared array detectors (HgCdTe). These are coupled via custom-built data acquisition electronics to a personal computer for data processing. This data acquisition system performs signal handling on a shot-by-shot basis at the 1 kHz repetition rate of the pulsed laser system. The combination of real-time signal processing and the ability to normalize each probe and reference pulse has enabled us to achieve a high sensitivity on the order of deltaOD approximately 10(-4) - 10(-5) with 1 min of acquisition time. We present preliminary picosecond TRIR studies using this spectrometer and also demonstrate how a combination of TRIR and TR3 spectroscopy can provide key information for the full elucidation of a photochemical process. PMID:14658632

  5. Experimental validation of Monte Carlo modeling of fluorescence in tissues in the UV-visible spectrum.

    PubMed

    Liu, Quan; Zhu, Changfang; Ramanujam, Nirmala

    2003-04-01

    The goal of the work is to experimentally verify Monte Carlo modeling of fluorescence and diffuse reflectance measurements in turbid, tissue phantom models. In particular, two series of simulations and experiments, in which one optical parameter (absorption or scattering coefficient) is varied while the other is fixed, are carried out to assess the effect of the absorption coefficient (mu(a)) and scattering coefficient (mu(s)) on the fluorescence and diffuse reflectance measured from a turbid medium. Moreover, simulations and experiments are carried out for several fiber optic probe geometries that are designed to sample small tissue volumes. Additionally, a group of conversion expressions are derived to convert the optical properties and fluorescence quantum yield measured from tissue phantoms for use in Monte Carlo simulations. The conversions account for the differences between the definitions of the absorption coefficient and fluorescence quantum yield of fluorophores in a tissue phantom model and those in a Monte Carlo simulation. The results indicate that there is good agreement between the simulated and experimentally measured results in most cases. This dataset can serve as a systematic validation of Monte Carlo modeling of fluorescent light propagation in tissues. The simulations are carried out for a wide range of absorption and scattering coefficients as well as ratios of scattering coefficient to absorption coefficient, and thus would be applicable to tissue optical properties over a wide wavelength range (UV-visible/near infrared). The fiber optic probe geometries that are modeled in this study include those commonly used for measuring fluorescence from tissues in practice. PMID:12683848

  6. Measurement of carboxyhemoglobin in forensic blood samples using UV-visible spectrometry and improved principal component regression

    Microsoft Academic Search

    William J. Egan; Stephen L. Morgan

    1999-01-01

    The forensic determination of carboxyhemoglobin (COHb) in blood was performed by using an improved principal component regression (PCR) technique applied to UV-visible spectra. Calibration data were decomposed into principal components, and the principal components useful for prediction were selected by their correlation with calibration spectra. Cross-validation of prediction results was done by leverage-corrected residuals. Confidence and prediction intervals derived from

  7. Characterizing human pancreatic cancer precursor using quantitative tissue optical spectroscopy

    PubMed Central

    Lee, Seung Yup; Lloyd, William R.; Chandra, Malavika; Wilson, Robert H.; McKenna, Barbara; Simeone, Diane; Scheiman, James; Mycek, Mary-Ann

    2013-01-01

    In a pilot study, multimodal optical spectroscopy coupled with quantitative tissue-optics models distinguished intraductal papillary mucinous neoplasm (IPMN), a common precursor to pancreatic cancer, from normal tissues in freshly excised human pancreas. A photon-tissue interaction (PTI) model extracted parameters associated with cellular nuclear size and refractive index (from reflectance spectra) and extracellular collagen content (from fluorescence spectra). The results suggest that tissue optical spectroscopy has the potential to characterize pre-cancerous neoplasms in human pancreatic tissues. PMID:24409383

  8. Quantitative analysis of anatase in Georgia kaolins using Raman spectroscopy

    Microsoft Academic Search

    Paul A. Schroeder; Nathan D. Melear; Robert J. Pruett

    2003-01-01

    Raman spectroscopy of Georgia kaolins ubiquitously show a strong Eg frequency near 144 cm?1. Analysis of the band intensity shows that under specific source, sample, and optical conditions, peak area measurements are predictable and reproducible. Using standard additions, successful quantitative techniques have been developed that allow analysis of 25% solids water slurries, which achieve anatase detection limits down to 0.3%

  9. Quantitative analysis using remote laser-induced breakdown spectroscopy (LIBS)

    Microsoft Academic Search

    C. M. Davies; H. H. Telle; D. J. Montgomery; R. E. Corbett

    1995-01-01

    A measurement system for quantitative, remote materials analysis has been realised. It is based on the method of laser-induced breakdown spectroscopy (LIBS), utilising an optical fibre system, both to deliver the laser radiation to the sample specimen and to collect the light emission from the luminous plasma plume. Distances of up to 100 m between the remote location and the

  10. Intrinsic Raman spectroscopy for quantitative biological spectroscopy Part II

    PubMed Central

    Bechtel, Kate L.; Shih, Wei-Chuan; Feld, Michael S.

    2009-01-01

    We demonstrate the effectiveness of intrinsic Raman spectroscopy (IRS) at reducing errors caused by absorption and scattering. Physical tissue models, solutions of varying absorption and scattering coefficients with known concentrations of Raman scatterers, are studied. We show significant improvement in prediction error by implementing IRS to predict concentrations of Raman scatterers using both ordinary least squares regression (OLS) and partial least squares regression (PLS). In particular, we show that IRS provides a robust calibration model that does not increase in error when applied to samples with optical properties outside the range of calibration. PMID:18711512

  11. Basic Principles of Spectroscopy

    NASA Astrophysics Data System (ADS)

    Penner, Michael H.

    Spectroscopy deals with the production, measurement, and interpretation of spectra arising from the interaction of electromagnetic radiation with matter. There are many different spectroscopic methods available for solving a wide range of analytical problems. The methods differ with respect to the species to be analyzed (such as molecular or atomic spectroscopy), the type of radiation-matter interaction to be monitored (such as absorption, emission, or diffraction), and the region of the electromagnetic spectrum used in the analysis. Spectroscopic methods are very informative and widely used for both quantitative and qualitative analyses. Spectroscopic methods based on the absorption or emission of radiation in the ultraviolet (UV), visible (Vis), infrared (IR), and radio (nuclear magnetic resonance, NMR) frequency ranges are most commonly encountered in traditional food analysis laboratories. Each of these methods is distinct in that it monitors different types of molecular or atomic transitions. The basis of these transitions is explained in the following sections.

  12. Design of a helix-bundle cross-link: NMR and UV-visible spectroscopic analyses and molecular modeling of ring-oxidized retinals.

    PubMed

    Williams, T C; Mani, V

    1991-03-19

    In order to generate potential chemical cross-links for studying the chromophore binding site of bacteriorhodopsin and related helix-bundle proteins, MnO2 was used to oxidize all-trans-retinal's ring moiety. The structures and solution conformations of three ring-oxidized retinal analogues have been determined by using UV-visible absorption and 1H and 13C NMR spectroscopies, primarily with regard to (i) the introduction of a functional group at the ring end of the chromophore, (ii) the retention of the all-trans geometry of the polyenal side chain, and (iii) the torsional angle of the ring-polyenal bond. Analyses of their UV-visible absorption spectral parameters (lambda max, epsilon max, and vibrational fine structure) and NMR spectral parameters (1H-1H coupling constants, 1H and 13C NMR chemical shifts, and 1H homonuclear Overhauser effects) indicated the 4-oxo and the 2,3-dehydro-4-oxo derivatives both possess the twisted 6-s-cis conformation adopted by most six-membered ring analogues of retinal in solution or crystal. However, the alpha-dioxocyclopentenyl analogue exists in solution predominantly (70-80%) as the planar 6-s-trans conformer, similar to violerythrine chromophore analogues. In order to identify the minor solution forms, molecular modeling and geometry optimizations using the semiempirical molecular orbital method AM1 defined two additional symmetry-related minima at +/- 30-40 degrees in its C6-C7 torsional energy profile. Because the chromophores of bacterio- and halorhodopsins and sensory rhodopsins are bound as the 6-s-trans conformer [Harbison, G.S., Smith, S.O., Pardoen, J.A., Courtin, J.M.L., Lugtenburg, J., Herzfeld, J., Mathies, R.A., & Griffin, R.G. (1985) Biochemistry 24, 6955-6962; Baselt, D.R., Fodor, S.P.A., van der Steen, R., Lugtenburg, J., Bogomolni, R.A., & Mathies, R.A. (1989) Biophys. J. 55, 193-196], we suggest that the cyclopentenyl analogue's alpha-diketo function may be favorably positioned within the binding pocket and sufficiently reactive toward nucleophilic attack to cross-link an arginine located in or near the ring end of the chromophore cavity: Arg134 according to the current model of bacteriorhodopsin's tertiary structure [Henderson, R., Baldwin, J.M., Ceska, T.A., Zemlin, F., Beckmann, E., & Downing, K.H. (1990) J. Mol. Biol. 213, 899-929] or Arg82 as postulated from an alternate model constructed primarily to accommodate the external point charge contribution to bacteriorhodopsin's opsin shift. PMID:2007133

  13. Investigation of ground state charge transfer complex between paracetamol and p-chloranil through DFT and UV-visible studies

    NASA Astrophysics Data System (ADS)

    Shukla, Madhulata; Srivastava, Nitin; Saha, Satyen

    2012-08-01

    The present report deals with the theoretical investigation on ground state structure and charge transfer (CT) transitions in paracetamol (PA)/p-chloranil (CA) complex using Density Functional Theory (DFT) and Time Dependent Density Functional Theory (TD-DFT) method. It is found that Cdbnd O bond length of p-chloranil increases on complexation with paracetamol along with considerable amount of charge transfer from PA to CA. TD-DFT calculations have been performed to analyse the observed UV-visible spectrum of PA-CA charge transferred complex. Interestingly, in addition to expected CT transition, a weak symmetry relieved ?-?* transition in the chloranil is also observed.

  14. Preparation of TiO2/(TiO2-V2O5)/polypyrrole nanocomposites and a study on catalytic activities of the hybrid materials under UV/Visible light and in the dark

    NASA Astrophysics Data System (ADS)

    Piewnuan, C.; Wootthikanokkhan, J.; Ngaotrakanwiwat, P.; Meeyoo, V.; Chiarakorn, S.

    2014-11-01

    Hybrid metal oxides/polymer nanocomposites, namely TiO2/(TiO2-V2O5)/polypyrrole (PPy), were synthesized via in situ polymerization. Structures of the products were characterized by SEM-EDX, XRD, and FTIR techniques. The light absorbance and band gap energy values of the materials were evaluated by UV/Visible spectroscopy. The catalytic activity of the materials was determined from a degradation of methylene blue. It was found that, regardless of the polymerization time, the absorbance of TiO2/(TiO2-V2O5)/PPy was greater than those of TiO2/PPy and the neat TiO2, respectively. This was in accordance with the decrease in the band gap energy of the materials. The catalytic activity of TiO2/(TiO2-V2O5) was also observed in the dark. After polymerization, the catalytic activity of nanocomposite under UV/Visible light and in the dark was compromised. The above effects are discussed in the light of the energy storage ability of V2O5 and capability of the polymer in acting as a binder for the system.

  15. Quantitative and Rapid DNA Detection by Laser Transmission Spectroscopy

    PubMed Central

    Li, Frank; Mahon, Andrew R.; Barnes, Matthew A.; Feder, Jeffery; Lodge, David M.; Hwang, Ching-Ting; Schafer, Robert; Ruggiero, Steven T.; Tanner, Carol E.

    2011-01-01

    Laser transmission spectroscopy (LTS) is a quantitative and rapid in vitro technique for measuring the size, shape, and number of nanoparticles in suspension. Here we report on the application of LTS as a novel detection method for species-specific DNA where the presence of one invasive species was differentiated from a closely related invasive sister species. The method employs carboxylated polystyrene nanoparticles functionalized with short DNA fragments that are complimentary to a specific target DNA sequence. In solution, the DNA strands containing targets bind to the tags resulting in a sizable increase in the nanoparticle diameter, which is rapidly and quantitatively measured using LTS. DNA strands that do not contain the target sequence do not bind and produce no size change of the carboxylated beads. The results show that LTS has the potential to become a quantitative and rapid DNA detection method suitable for many real-world applications. PMID:22195026

  16. Quantitative and rapid DNA detection by laser transmission spectroscopy.

    PubMed

    Li, Frank; Mahon, Andrew R; Barnes, Matthew A; Feder, Jeffery; Lodge, David M; Hwang, Ching-Ting; Schafer, Robert; Ruggiero, Steven T; Tanner, Carol E

    2011-01-01

    Laser transmission spectroscopy (LTS) is a quantitative and rapid in vitro technique for measuring the size, shape, and number of nanoparticles in suspension. Here we report on the application of LTS as a novel detection method for species-specific DNA where the presence of one invasive species was differentiated from a closely related invasive sister species. The method employs carboxylated polystyrene nanoparticles functionalized with short DNA fragments that are complimentary to a specific target DNA sequence. In solution, the DNA strands containing targets bind to the tags resulting in a sizable increase in the nanoparticle diameter, which is rapidly and quantitatively measured using LTS. DNA strands that do not contain the target sequence do not bind and produce no size change of the carboxylated beads. The results show that LTS has the potential to become a quantitative and rapid DNA detection method suitable for many real-world applications. PMID:22195026

  17. Total ozone measured during EASOE by a UV-visible spectrometer which observes stars

    Microsoft Academic Search

    D. J. Fish; R. L. Jones; R. A. Freshwater; H. K. Roscoe; D. J. Oldham; J. E. Harries

    1994-01-01

    This paper presents the results of ground based measurement of column ozone from Abisko, Sweden (68.4[degrees]N), by means of a novel absorption spectroscopy technique. The instrument uses starlight, and moon glow as sources of UV and visible light for the absorption technique. These measurements were compared with ozonesonde measurements, and with space borne instruments.

  18. Optical spectroscopy for quantitative sensing in human pancreatic tissues

    NASA Astrophysics Data System (ADS)

    Wilson, Robert H.; Chandra, Malavika; Lloyd, William; Chen, Leng-Chun; Scheiman, James; Simeone, Diane; McKenna, Barbara; Mycek, Mary-Ann

    2011-07-01

    Pancreatic adenocarcinoma has a five-year survival rate of only 6%, largely because current diagnostic methods cannot reliably detect the disease in its early stages. Reflectance and fluorescence spectroscopies have the potential to provide quantitative, minimally-invasive means of distinguishing pancreatic adenocarcinoma from normal pancreatic tissue and chronic pancreatitis. The first collection of wavelength-resolved reflectance and fluorescence spectra and time-resolved fluorescence decay curves from human pancreatic tissues was acquired with clinically-compatible instrumentation. Mathematical models of reflectance and fluorescence extracted parameters related to tissue morphology and biochemistry that were statistically significant for distinguishing between pancreatic tissue types. These results suggest that optical spectroscopy has the potential to detect pancreatic disease in a clinical setting.

  19. Quantitative analysis of gallstones using laser-induced breakdown spectroscopy

    SciTech Connect

    Singh, Vivek K.; Singh, Vinita; Rai, Awadhesh K.; Thakur, Surya N.; Rai, Pradeep K.; Singh, Jagdish P

    2008-11-01

    The utility of laser-induced breakdown spectroscopy (LIBS) for categorizing different types of gallbladder stone has been demonstrated by analyzing their major and minor constituents. LIBS spectra of three types of gallstone have been recorded in the 200-900 nm spectral region. Calcium is found to be the major element in all types of gallbladder stone. The spectrophotometric method has been used to classify the stones. A calibration-free LIBS method has been used for the quantitative analysis of metal elements, and the results have been compared with those obtained from inductively coupled plasma atomic emission spectroscopy (ICP-AES) measurements. The single-shot LIBS spectra from different points on the cross section (in steps of 0.5 mm from one end to the other) of gallstones have also been recorded to study the variation of constituents from the center to the surface. The presence of different metal elements and their possible role in gallstone formation is discussed.

  20. Determination of oil-in-water using nanoemulsions as solvents and UV visible and total organic carbon detection methods.

    PubMed

    Costa, Josane A; Farias, Naiara C; Queirós, Yure G C; Mansur, Claudia R E

    2013-03-30

    The aim of this study was to investigate the application of oil in water (O/W) nanoemulsion as solvent in the extraction step for determination of oil content in oily water, measured using a UV visible spectrophotometer (UV-vis) and a total organic carbon (TOC) analyzer. The optical micrographs and distribution size curves showed that the use of a small amount of nanoemulsion was capable of transforming the oily water in a colloidal dispersion that can be read in the UV-vis and TOC-VCHS devices. The oil content results obtained showed great accuracy between the measurements, with very low average standard deviation (?5%) for both UV-vis and TOC-VCHS. The new methods suggested in this work are very promising, since they allow simple, quick and accurate analyses, and especially require a lower volume of solvent (less than 1%) compared to those used in conventional analytic methods. PMID:23598227

  1. Mapping of local oxide properties by quantitative scanning capacitance spectroscopy

    SciTech Connect

    Brezna, W.; Harasek, S.; Lugstein, A.; Leitner, T.; Hoffmann, H.; Bertagnolli, E.; Smoliner, J. [Institut fuer Festkoerperelektronik, Technische Universitaet Wien, Floragasse 7, A-1040 Vienna (Austria); Institut fuer Angewandte Synthesechemie, Technische Universitat Wien, Getreidemarkt 9/163, A-1060 Vienna (Austria); Institut fuer Festkoerperelektronik, Technische Universitaet Wien, Floragasse 7, A-1040 Vienna (Austria)

    2005-05-01

    In this work, quantitative scanning capacitance spectroscopy was applied to investigate the local dielectric properties of a chemical vapor deposition grown ZrO{sub 2} layer on low-doped silicon. Due to self-organization effects during the growth process, the ZrO{sub 2} layer shows small, periodic thickness variations on micrometer length scales near the sample edges. The measured capacitance data and derived oxide charge densities show the same periodicity as the thickness variations. The magnitude of the change of the oxide charge density, however, cannot be explained by the small thickness variations and is attributed to a local periodic change of the growth dynamics.

  2. Sacrificial hydrogen generation from aqueous triethanolamine with Eosin Y-sensitized Pt/TiO2 photocatalyst in UV, visible and solar light irradiation.

    PubMed

    Chowdhury, Pankaj; Gomaa, Hassan; Ray, Ajay K

    2015-02-01

    In this paper, we have studied Eosin Y-sensitized sacrificial hydrogen generation with triethanolamine as electron donor in UV, visible, and solar light irradiation. Aeroxide TiO2 was loaded with platinum metal via solar photo-deposition method to reduce the electron hole recombination process. Photocatalytic sacrificial hydrogen generation was influenced by several factors such as platinum loading (wt%) on TiO2, solution pH, Eosin Y to Pt/TiO2 mass ratio, triethanolamine concentration, and light (UV, visible and solar) intensities. Detailed reaction mechanisms in visible and solar light irradiation were established. Oxidation of triethanolamine and formaldehyde formation was correlated with hydrogen generation in both visible and solar lights. Hydrogen generation kinetics followed a Langmuir-type isotherm with reaction rate constant and adsorption constant of 6.77×10(-6) mol min(-1) and 14.45 M(-1), respectively. Sacrificial hydrogen generation and charge recombination processes were studied as a function of light intensities. Apparent quantum yields (QYs) were compared for UV, visible, and solar light at four different light intensities. Highest QYs were attained at lower light intensity because of trivial charge recombination. At 30 mW cm(-2) we achieved QYs of 10.82%, 12.23% and 11.33% in UV, visible and solar light respectively. PMID:25441927

  3. UV-visible microscope spectrophotometric polarization and dichroism with increased discrimination power in forensic analysis

    NASA Astrophysics Data System (ADS)

    Purcell, Dale Kevin

    Microanalysis of transfer (Trace) evidence is the application of a microscope and microscopical techniques for the collection, observation, documentation, examination, identification, and discrimination of micrometer sized particles or domains. Microscope spectrophotometry is the union of microscopy and spectroscopy for microanalysis. Analytical microspectroscopy is the science of studying the emission, reflection, transmission, and absorption of electromagnetic radiation to determine the structure or chemical composition of microscopic-size materials. Microscope spectrophotometry instrument designs have evolved from monochromatic illumination which transmitted through the microscope and sample and then is detected by a photometer detector (photomultiplier tube) to systems in which broad-band (white light) illumination falls incident upon a sample followed by a non-scanning grating spectrometer equipped with a solid-state multi-element detector. Most of these small modern spectrometers are configured with either silicon based charged-couple device detectors (200-950 nm) or InGaAs based diode array detectors (850-2300 nm) with computerized data acquisition and signal processing being common. A focus of this research was to evaluate the performance characteristics of various modern forensic (UV-Vis) microscope photometer systems as well as review early model instrumental designs. An important focus of this research was to efficiently measure ultraviolet-visible spectra of microscopically small specimens for classification, differentiation, and possibly individualization. The first stage of the project consisted of the preparation of microscope slides containing neutral density filter reference materials, molecular fluorescence reference materials, and dichroic reference materials. Upon completion of these standard slide preparations analysis began with measurements in order to evaluate figures of merit for comparison of the instruments investigated. The figures of merit investigated included: 1) wavelength accuracy, 2) wavelength precision, 3) wavelength resolution stability, 4) photometric accuracy, 5) photometric precision, 6) photometric linearity, 7) photometric noise, and 8) short-term baseline stability. In addition, intrinsic instrument polarization effects were investigated to determine the impact of these properties on spectral interpretation and data quality. Finally, a set of recommendations were developed which describe instrument performance characteristics for microscope and spectrometer features and functions, and specific instrument parameters that must be controlled in order to acquire high quality data from an ultraviolet-visible forensic microscope spectrophotometer system for increased discrimination power.

  4. X-ray radiolysis induced formation of silver nano-particles: A SAXS and UV–visible absorption spectroscopy study

    Microsoft Academic Search

    S. Remita; P. Fontaine; E. Lacaze; Y. Borensztein; H. Sellame; R. Farha; C. Rochas; M. Goldmann

    2007-01-01

    We show that X-ray irradiation of metal salt aqueous solutions in the absence of any stabilizer leads to the synthesis of metal nano-particles, similarly to ?-ray irradiation. The chemical route is the reduction of silver metal ions induced by radiolysis of water. Moreover, X-rays used for the synthesis allow following in situ the formation of silver nano-particles by Small Angle

  5. UV/visible spectroscopy of matrix-isolated hexa-peri-hexabenzocoronene: Interacting electronic states and astrophysical context

    NASA Astrophysics Data System (ADS)

    Rouillé, Gaël; Steglich, Mathias; Huisken, Friedrich; Henning, Thomas; Müllen, Klaus

    2009-11-01

    Absorption spectra of hexa-peri-hexabenzocoronene isolated in rare-gas matrices are reported for the wavelength range between 200 and 500 nm. Measurements were carried out in neon and in argon at 5.8 and 12.0 K, respectively. Calculations based on semiempirical models and on density-functional theory were performed to assign the observed features. The electronically excited states involved in Clar's ?- and p-bands are identified as S1(B2u) and S2(B1u), respectively. Although the upper state associated with the ?-band is found to be a 1E1u state, it remains undetermined whether it is S3 or S4. Structures in the ?-band are interpreted as resulting from the interaction between the 1E1u state and the e2g vibrational manifold of S2(B1u). The new measurements are used to narrow down the wavelength ranges where the bands of hexa-peri-hexabenzocoronene should be found in the gas phase. A previous estimate of the interstellar abundance of this polycyclic aromatic hydrocarbon is discussed.

  6. The UV-visible absorption and fluorescence spectroscopy indicators for monitoring the evolution of green waste composts.

    NASA Astrophysics Data System (ADS)

    Mounier, Stéphane; Abaker, Madi; Domeizel, Mariane; Rapetti, Nicola

    2014-05-01

    The maturity process of compost goes through several phases that have to be monitored in order to optimize the production process which in turn assure a good quality product and less time consumption. In order to estimate rapidly the phase where the compost is present and to measure the cellulose, the ratio C:N and the Stability Index Organic Matter (ISMO) a crucial parameter that needs to be monitored and controlled is the temperature. However, the temperature is not really a good indicator for the maturity of the compost because it is not constant and it depends on the mixing and environmental processes. The final measurements are performed at the end of the production process after certain time period that is subjectively determined by the producer. The work presented here is based on the optical properties of the organic matter that are observed each month for a period of six months. The organic matter of 5 composts was extracted by water and analyzed by UV-VIS spectroscopic technique [1] and 3D fluorescence emission technique [2]. The usual indexes were calculated (E2/E3, E4/E6, EBZ/EET, SUVA254), but also the PARAFAC decomposition of the 3D fluorescence response by Milori [3] and the Hx indexes [4]. The comparison of these results and the cellulose composition with the corresponding ISMO index indicates that the maturity process occurs more rapidly then the expectation of the producers. Further, the combination of the indicators gives useful information about different processes that take place during the maturity of the compost such as aromatization, the condensation and the stabilization of the parameters.

  7. UV-visible spectroscopic estimation of photodegradation of rhodamine-B dye using tin(IV) oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Sangami, G.; Dharmaraj, N.

    2012-11-01

    Nanocrystalline, tin(IV) oxide (SnO2) particles has been prepared by thermal decomposition of tin oxalate precursor obtained from the reactions of tin(IV) chloride and sodium oxalate using eggshell membrane (ESM). The as-prepared SnO2 nanoparticles were characterized by thermal studies, transmission electron microscopy (TEM), powder X-ray diffraction (XRD), Raman, FT-IR and UV-visible studies and used as a photocatalyst for the degradation of rhodamine-B (Rh-B) dye. The size of the prepared nanoparticles was in the range of 5-12 nm as identified from the TEM images. Powder XRD data revealed the presence of a tetragonal, rutile crystalline phase of the tin(IV) oxide nanoparticles. Thermal analysis showed that the decomposition of tin oxalate precursor to yield the titled tin(IV) oxide nanoparticles was completed below 500 °C. The extent of degradation of Rh-B in the presence of SnO2 monitored by absorption spectral measurements demonstrated that 94.48% of the selected dye was degraded upon irradiation with UV light for 60 min.

  8. Quantitative Surface Atomic Structure Analysis by Low-Energy Ion Scattering Spectroscopy (ISS)

    Microsoft Academic Search

    Masakazu Aono; Ryutaro Souda

    1985-01-01

    Surface atomic structure analysis by low-energy ion scattering spectroscopy (ISS) is reviewed, with particular emphasis on quantitative surface atomic structure analysis by ISS. The important differences between ISS and Rutherford backscattering spectroscopy (RBS), some basic characteristics of ISS, a special type of ISS called impact-collision ion scattering spectroscopy (ICISS), and the general features of the shadow cone in the energy

  9. ZnO(N)-Spiro-MeOTAD hybrid photodiode: an efficient self-powered fast-response UV (visible) photosensor.

    PubMed

    Game, Onkar; Singh, Upendra; Kumari, Tanya; Banpurkar, Arun; Ogale, Satishchandra

    2014-01-01

    Organic-inorganic hybrid photo-detectors with a self-sufficient mode of operation represent a research area of great current interest. In most efficient photodetectors and optoelectronic devices compound semiconductors containing toxic elements such as Cd, As, Te, S, Se etc. are used and these are also expensive. Hence there is also a rapidly growing interest in replacing these with environmentally friendly and earth-abundant materials. Herein, we report a facile solution-processed fabrication of a self-powered organic-inorganic hybrid photodetector using n-type oriented ZnO nanorods and p-type Spiro-MeOTAD semiconductor. ZnO is eco-friendly and earth-abundant, and Spiro-MeOTAD is non-hazardous. We show that the latter has far less toxicity than the toxic elements stated above. This visible blind UV photodetector shows high sensitivity (10(2)) and a UV/visible rejection ratio of 300. It also exhibits fast response times of ?(rise) ~ 200 ?s and ?(fall) ~ 950 ?s. Importantly, with a small modification of nitrogen incorporation in ZnO one can also realize a highly-sensitive self-powered visible light photodetector with at least 1000% (or higher) improvements in quality factors (photocurrent/sensitivity/response time) as compared to previously reported organic-inorganic hybrid photo-detectors based on metal-chalcogenides (CdS-PANI or CuInSe2-P3HT). Interestingly, the broadband sensitivity of such N:ZnO-Spiro-MeOTAD photodiode enables sensing of low intensity (~28 ?W cm(-2)) ambient white light with a high photocurrent density of 120 nA cm(-2) making it an efficient ambient white light detector. PMID:24232600

  10. Quantitative Characterization of Tissue Microstructure with Temporal Diffusion Spectroscopy

    PubMed Central

    Xu, Junzhong; Does, Mark D.; Gore, John C.

    2009-01-01

    The signals recorded by diffusion-weighted magnetic resonance imaging (DWI) are dependent on the micro-structural properties of biological tissues, so it is possible to obtain quantitative structural information non-invasively from such measurements. Oscillating gradient spin echo (OGSE) methods have the ability to probe the behavior of water diffusion over different time scales and the potential to detect variations in intracellular structure. To assist in the interpretation of OGSE data, analytical expressions have been derived for diffusion-weighted signals with OGSE methods for restricted diffusion in some typical structures, including parallel planes, cylinders and spheres, using the theory of temporal diffusion spectroscopy. These analytical predictions have been confirmed with computer simulations. These expressions suggest how OGSE signals from biological tissues should be analyzed to characterize tissue microstructure, including how to estimate cell nuclear sizes. This approach provides a model to interpret diffusion data obtained from OGSE measurements that can be used for applications such as monitoring tumor response to treatment in vivo. PMID:19616979

  11. Direct-potential-fit analysis of new infrared and UV\\/visible A 1?+-X 1?+ emission spectra of AgH and AgD

    Microsoft Academic Search

    Robert J. Le Roy; Dominique R. T. Appadoo; Kevin Anderson; Alireza Shayesteh; Iouli E. Gordon; Peter F. Bernath

    2005-01-01

    New high-resolution infrared and UV\\/visible spectra of 107AgH, 109AgH, 107AgD, and 109AgD have been recorded with a Fourier transform spectrometer. The new line positions are combined with published microwave and older electronic A 1?+-X 1?+ data and used, first in a decoupled analysis of the X state alone, and then in a global multi-isotopologue analysis which yields comprehensive descriptions of

  12. Characterization of aquatic dissolved organic matter by asymmetrical flow field-flow fractionation coupled to UV–Visible diode array and excitation emission matrix fluorescence

    Microsoft Academic Search

    Céline Guéguen; Chad W. Cuss

    2011-01-01

    Flow field-flow fractionation (FlFFF) with on-line UV\\/Visible diode array detector (DAD) and excitation emission matrix (EEM) fluorescence detector has been developed for the characterization of optical properties of aquatic dissolved organic matter (DOM) collected in the Otonabee River (Ontario, Canada) and Athabasca River (Alberta, Canada). The molecular weight (MW) distribution of DOM was estimated using a series of organic macromolecules

  13. A new tridentate Schiff base Cu(II) complex: Synthesis, experimental and theoretical studies on its crystal structure, FT-IR and UV-Visible spectra

    NASA Astrophysics Data System (ADS)

    Saheb, Vahid; Sheikhshoaie, Iran; Setoodeh, Nasim; Rudbari, Hadi Amiri; Bruno, Giuseppe

    2013-06-01

    A new Cu(II) complex [Cu(L)(NCS)] has been synthesized, using 1-(N-salicylideneimino)-2-(N,N-methyl)-aminoethane as tridentate ONN donor Schiff base ligand (HL). The dark green crystals of the compound are used for single-crystal X-ray analysis and measuring Fourier Transform Infrared (FT-IR) and UV-Visible spectra. Electronic structure calculations at the B3LYP and MP2 levels of theory are performed to optimize the molecular geometry and to calculate the UV-Visible and FT-IR spectra of the compound. Vibrational assignments and analysis of the fundamental modes of the compound are performed. Time-dependent density functional theory (TD-DFT) method is used to calculate the electronic transitions of the complex. A scaling factor of 1.015 is obtained for vibrational frequencies computed at the B3LYP level using basis sets 6-311G(d,p). It is found that solvent has a profound effect on the electronic absorption spectrum. The UV-Visible spectrum of the complex recorded in DMSO and DMF solution can be correctly predicted by a model in which DMSO and DMF molecules are coordinated to the central Cu atom via their oxygen atoms.

  14. A new tridentate Schiff base Cu(II) complex: synthesis, experimental and theoretical studies on its crystal structure, FT-IR and UV-Visible spectra.

    PubMed

    Saheb, Vahid; Sheikhshoaie, Iran; Setoodeh, Nasim; Rudbari, Hadi Amiri; Bruno, Giuseppe

    2013-06-01

    A new Cu(II) complex [Cu(L)(NCS)] has been synthesized, using 1-(N-salicylideneimino)-2-(N,N-methyl)-aminoethane as tridentate ONN donor Schiff base ligand (HL). The dark green crystals of the compound are used for single-crystal X-ray analysis and measuring Fourier Transform Infrared (FT-IR) and UV-Visible spectra. Electronic structure calculations at the B3LYP and MP2 levels of theory are performed to optimize the molecular geometry and to calculate the UV-Visible and FT-IR spectra of the compound. Vibrational assignments and analysis of the fundamental modes of the compound are performed. Time-dependent density functional theory (TD-DFT) method is used to calculate the electronic transitions of the complex. A scaling factor of 1.015 is obtained for vibrational frequencies computed at the B3LYP level using basis sets 6-311G(d,p). It is found that solvent has a profound effect on the electronic absorption spectrum. The UV-Visible spectrum of the complex recorded in DMSO and DMF solution can be correctly predicted by a model in which DMSO and DMF molecules are coordinated to the central Cu atom via their oxygen atoms. PMID:23562742

  15. Practical aspects of quantitative laser Raman microprobe spectroscopy for the study of fluid inclusions

    Microsoft Academic Search

    J. D. Pasteris; B. Wopenka; J. C. Seitz

    1988-01-01

    This paper is addressed to both geologists who use laser Raman microprobe (LRM) spectroscopy to analyze fluid inclusions and to those who want to evaluate analyses done by this technique. Emphasis is on how to obtain quantitative analyses of fluid inclusions. The authors discuss the basic method of fluid inclusion analysis by LRM spectroscopy and the levels of accuracy and

  16. Fundamentals of Vibronic Spectroscopy John A. Shelnutt

    E-print Network

    Shelnutt, John A.

    Fundamentals of Vibronic Spectroscopy John A. Shelnutt Department of Chemistry University. #12;Fundamentals of Vibronic Spectroscopy Copyright © 2008-2013 by John A. Shelnutt. All rights be electromagnetic radiation consisting of -rays, X- rays, UV-visible-NIR light, infrared light, microwaves, radio

  17. Fundamentals of Vibronic Spectroscopy John A. Shelnutt

    E-print Network

    Shelnutt, John A.

    Fundamentals of Vibronic Spectroscopy John A. Shelnutt Advanced Materials Laboratory Sandia;Fundamentals of Vibronic Spectroscopy Copyright © 2008 by John A. Shelnutt. All rights reserved. 2 PREFACE of -rays, X-rays, UV-visible-NIR light, infrared light, microwaves, radio waves, or other particle fields

  18. Quantitative Determination of DNA-Ligand Binding Using Fluorescence Spectroscopy

    ERIC Educational Resources Information Center

    Healy, Eamonn F.

    2007-01-01

    The effective use of fluorescence spectroscopy for determining the binding of the intercalcating agent crhidium bromide to DNA is being described. The analysis used simple measurement techniques and hence can be easily adopted by the students for a better understanding.

  19. Piezo-phototronic Effect Enhanced UV/Visible Photodetector Based on Fully Wide Band Gap Type-II ZnO/ZnS Core/Shell Nanowire Array.

    PubMed

    Rai, Satish C; Wang, Kai; Ding, Yong; Marmon, Jason K; Bhatt, Manish; Zhang, Yong; Zhou, Weilie; Wang, Zhong Lin

    2015-06-23

    A high-performance broad band UV/visible photodetector has been successfully fabricated on a fully wide bandgap ZnO/ZnS type-II heterojunction core/shell nanowire array. The device can detect photons with energies significantly smaller (2.2 eV) than the band gap of ZnO (3.2 eV) and ZnS (3.7 eV), which is mainly attributed to spatially indirect type-II transition facilitated by the abrupt interface between the ZnO core and ZnS shell. The performance of the device was further enhanced through the piezo-phototronic effect induced lowering of the barrier height to allow charge carrier transport across the ZnO/ZnS interface, resulting in three orders of relative responsivity change measured at three different excitation wavelengths (385, 465, and 520 nm). This work demonstrates a prototype UV/visible photodetector based on the truly wide band gap semiconducting 3D core/shell nanowire array with enhanced performance through the piezo-phototronic effect. PMID:26039323

  20. Journal of Quantitative Spectroscopy & Radiative Transfer 109 (2008) 19311942

    E-print Network

    2008-01-01

    with good TES sensitivity after accounting for its lower vertical sensitivity compared with the ACE FTS. r; Spectroscopy; Carbon monoxide ARTICLE IN PRESS www.elsevier.com/locate/jqsrt 0022-4073/$ - see front matter r@sciborg.uwaterloo.ca, cboone@acebox.uwaterloo.ca (C.D. Boone), bernath@uwaterloo.ca, pfb500@york.ac.uk (P.F. Bernath), linda.s.chiou

  1. Direct and quantitative photothermal absorption spectroscopy of individual particulates

    SciTech Connect

    Tong, Jonathan K.; Hsu, Wei-Chun; Eon Han, Sang; Burg, Brian R.; Chen, Gang, E-mail: gchen2@mit.edu [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Zheng, Ruiting [Key Laboratory of Radiation Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China)] [Key Laboratory of Radiation Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Shen, Sheng [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)] [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

    2013-12-23

    Photonic structures can exhibit significant absorption enhancement when an object's length scale is comparable to or smaller than the wavelength of light. This property has enabled photonic structures to be an integral component in many applications such as solar cells, light emitting diodes, and photothermal therapy. To characterize this enhancement at the single particulate level, conventional methods have consisted of indirect or qualitative approaches which are often limited to certain sample types. To overcome these limitations, we used a bilayer cantilever to directly and quantitatively measure the spectral absorption efficiency of a single silicon microwire in the visible wavelength range. We demonstrate an absorption enhancement on a per unit volume basis compared to a thin film, which shows good agreement with Mie theory calculations. This approach offers a quantitative approach for broadband absorption measurements on a wide range of photonic structures of different geometric and material compositions.

  2. Quantitative 2H NMR spectroscopy with 1H lock extender.

    PubMed

    Vignali, Carlo; Caligiani, Augusta; Palla, Gerardo

    2007-07-01

    An inexpensive external unit that allows the use of the commercial high-resolution NMR spectrometer for (2)H observation with an (1)H lock system is described. The external unit does not require any tuning, is extremely easy to use, and could be a cheaper and more straightforward alternative to the more expensive (19)F lock configuration. An application for the quantitative determination of the natural isotopic ratio (2)H/(1)H of ethanol and acetic acid is reported. PMID:17485230

  3. Model for quantitative tip-enhanced spectroscopy and the extraction of nanoscale-resolved optical constants

    NASA Astrophysics Data System (ADS)

    McLeod, Alexander S.; Kelly, P.; Goldflam, M. D.; Gainsforth, Z.; Westphal, A. J.; Dominguez, Gerardo; Thiemens, Mark H.; Fogler, Michael M.; Basov, D. N.

    2014-08-01

    Near-field infrared spectroscopy by elastic scattering of light from a probe tip resolves optical contrasts in materials at dramatically subwavelength scales across a broad energy range, with the demonstrated capacity for chemical identification at the nanoscale. However, current models of probe-sample near-field interactions still cannot provide a sufficiently quantitatively interpretation of measured near-field contrasts, especially in the case of materials supporting strong surface phonons. We present a model of near-field spectroscopy derived from basic principles and verified by finite-element simulations, demonstrating superb predictive agreement both with tunable quantum cascade laser near-field spectroscopy of SiO2 thin films and with newly presented nanoscale Fourier transform infrared (nanoFTIR) spectroscopy of crystalline SiC. We discuss the role of probe geometry, field retardation, and surface mode dispersion in shaping the measured near-field response. This treatment enables a route to quantitatively determine nanoresolved optical constants, as we demonstrate by inverting newly presented nanoFTIR spectra of an SiO2 thin film into the frequency dependent dielectric function of its mid-infrared optical phonon. Our formalism further enables tip-enhanced spectroscopy as a potent diagnostic tool for quantitative nanoscale spectroscopy.

  4. Quantitating Metabolites in Protein Precipitated Serum Using NMR Spectroscopy

    PubMed Central

    2015-01-01

    Quantitative NMR-based metabolite profiling is challenged by the deleterious effects of abundant proteins in the intact blood plasma/serum, which underscores the need for alternative approaches. Protein removal by ultrafiltration using low molecular weight cutoff filters thus represents an important step. However, protein precipitation, an alternative and simple approach for protein removal, lacks detailed quantitative assessment for use in NMR based metabolomics. In this study, we have comprehensively evaluated the performance of protein precipitation using methanol, acetonitrile, perchloric acid, and trichloroacetic acid and ultrafiltration approaches using 1D and 2D NMR, based on the identification and absolute quantitation of 44 human blood metabolites, including a few identified for the first time in the NMR spectra of human serum. We also investigated the use of a “smart isotope tag,” 15N-cholamine for further resolution enhancement, which resulted in the detection of a number of additional metabolites. 1H NMR of both protein precipitated and ultrafiltered serum detected all 44 metabolites with comparable reproducibility (average CV, 3.7% for precipitation; 3.6% for filtration). However, nearly half of the quantified metabolites in ultrafiltered serum exhibited 10–74% lower concentrations; specifically, tryptophan, benzoate, and 2-oxoisocaproate showed much lower concentrations compared to protein precipitated serum. These results indicate that protein precipitation using methanol offers a reliable approach for routine NMR-based metabolomics of human blood serum/plasma and should be considered as an alternative to ultrafiltration. Importantly, protein precipitation, which is commonly used by mass spectrometry (MS), promises avenues for direct comparison and correlation of metabolite data obtained from the two analytical platforms to exploit their combined strength in the metabolomics of blood. PMID:24796490

  5. Instrument independent diffuse reflectance spectroscopy

    PubMed Central

    Yu, Bing; Fu, Henry L.; Ramanujam, Nirmala

    2011-01-01

    Diffuse reflectance spectroscopy with a fiber optic probe is a powerful tool for quantitative tissue characterization and disease diagnosis. Significant systematic errors can arise in the measured reflectance spectra and thus in the derived tissue physiological and morphological parameters due to real-time instrument fluctuations. We demonstrate a novel fiber optic probe with real-time, self-calibration capability that can be used for UV-visible diffuse reflectance spectroscopy in biological tissue in clinical settings. The probe is tested in a number of synthetic liquid phantoms over a wide range of tissue optical properties for significant variations in source intensity fluctuations caused by instrument warm up and day-to-day drift. While the accuracy for extraction of absorber concentrations is comparable to that achieved with the traditional calibration (with a reflectance standard), the accuracy for extraction of reduced scattering coefficients is significantly improved with the self-calibration probe compared to traditional calibration. This technology could be used to achieve instrument-independent diffuse reflectance spectroscopy in vivo and obviate the need for instrument warm up and post?premeasurement calibration, thus saving up to an hour of precious clinical time. PMID:21280897

  6. UV-visible, Raman and E.S.R. studies of gamma-irradiated NiO-doped sodium metaphosphate glasses

    NASA Astrophysics Data System (ADS)

    ElBatal, Fatma H.; Morsi, Reham M.; Ouis, Mona A.; Marzouk, Samir Y.

    2010-11-01

    UV-visible spectroscopic measurements of Ni-doped sodium phosphate glasses were carried out before and after successive gamma irradiation. The undoped glass reveals strong UV absorption originating from trace iron impurities. NiO-doped glasses show characteristic absorption bands due mainly to octahedral coordination of Ni 2+ ions. Gamma irradiation produces induced bands generated from intrinsic defects and extrinsic defects. The changes in the spectroscopic data are discussed in relation to the structural evolution caused by the changes in composition and coordination state of nickel ions. The change in the growth behaviour of the induced bands is related to the annihilation or approach saturation of these characteristic induced bands. Raman and E.S.R. spectroscopic measurements confirm the presence of nickel as Ni 2+ ions in octahedral state.

  7. UV-visible, Raman and E.S.R. studies of gamma-irradiated NiO-doped sodium metaphosphate glasses.

    PubMed

    ElBatal, Fatma H; Morsi, Reham M; Ouis, Mona A; Marzouk, Samir Y

    2010-11-01

    UV-visible spectroscopic measurements of Ni-doped sodium phosphate glasses were carried out before and after successive gamma irradiation. The undoped glass reveals strong UV absorption originating from trace iron impurities. NiO-doped glasses show characteristic absorption bands due mainly to octahedral coordination of Ni(2+) ions. Gamma irradiation produces induced bands generated from intrinsic defects and extrinsic defects. The changes in the spectroscopic data are discussed in relation to the structural evolution caused by the changes in composition and coordination state of nickel ions. The change in the growth behaviour of the induced bands is related to the annihilation or approach saturation of these characteristic induced bands. Raman and E.S.R. spectroscopic measurements confirm the presence of nickel as Ni(2+) ions in octahedral state. PMID:20696612

  8. Quantitative Analysis of Spectroscopy's Study for Engine Oil Degradation Monitoring Due to Temperature Effect

    Microsoft Academic Search

    M. F. M. Idros; Sawal Ali

    2012-01-01

    This paper presents the quantitative analysis of spectroscopy measurement for engine oil degradation prediction due to the temperature effect. The main objective of this project is to study the behavior of engine oil if the continues high temperature are applied to the engine oil as compared to the effect of running condition. Two types of engine oil were used as

  9. Qualitative and quantitative analysis of chlorinated solvents using Raman spectroscopy and machine learning.

    E-print Network

    Madden, Michael

    models were developed to identify the presence of chlorinated solvents in mixtures at levels of ~5 solvent waste is chlorinated or not will determine firstly how it is transported for disposal and secondlyQualitative and quantitative analysis of chlorinated solvents using Raman spectroscopy and machine

  10. Self-absorption model in quantitative laser induced breakdown spectroscopy measurements on soils and sediments

    Microsoft Academic Search

    V. Lazic; R. Barbini; F. Colao; R. Fantoni; A. Palucci

    2001-01-01

    Application of laser induced breakdown spectroscopy (LIBS) in the quantitative analysis of elemental composition of soils with different origins and Antarctic marine sediments has been considered. The analytical method followed includes the usual plasma modeling at local thermal equilibrium (LTE) based on average temperature and electron density values, as well as spectra normalization, introduced in order to reduce the effects

  11. Quantitative elemental determination in water and oil by laser induced breakdown spectroscopy

    Microsoft Academic Search

    Pascal Fichet; Patrick Mauchien; Jean-François Wagner; Christophe Moulin

    2001-01-01

    Laser induced breakdown spectroscopy has been used to evaluate the potentiality of the technique for the determination of trace amounts of elements in different types of liquids, in the framework of nuclear applications. A specific set-up using a pulsed laser focussed with a tilted angle on the surface of the liquid is presented. It allows on-line quantitative measurements with good

  12. Quantitation of influenza A virus in the presence of extraneous protein using electrochemical impedance spectroscopy

    Microsoft Academic Search

    Walid Mohamed Hassen; Valérie Duplan; Eric Frost; Jan J. Dubowski

    2011-01-01

    In an attempt to provide an insight into detection of specific viruses in biological samples, we report on quantitation of influenza A virus (IAV) in samples containing large amounts of extraneous bovine serum albumin (BSA), foetal bovine serum (FBS) and hepatitis B virus (HBV) vaccine. Detection was carried out using electrochemical impedance spectroscopy (EIS) with an antibody-neutravidin-thiol architecture immobilized on

  13. Quantitative multiplex CARS spectroscopy in congested spectral regions

    NASA Astrophysics Data System (ADS)

    Müller, Michiel; Rinia, Hilde A.; Bonn, Mischa; Vartiainen, Erik M.; Lisker, Melanie; van Bel, Aart

    2007-02-01

    A novel procedure is developed to describe and reproduce experimental coherent anti-Stokes Raman scattering (CARS) data, with particular emphasis on highly congested spectral regions. The approach - exemplified here with high-quality multiplex CARS data - makes use the maximum entropy method for phase retrieval. The retrieved imaginary part of the nonlinear susceptibility is shown to be equal to the spontaneous Raman spectrum. The phase retrieval procedure does not influence the noise contained in the spectra. The conversion of CARS to Raman data permits a quantitative interpretation of CARS spectra. This novel approach is demonstrated for highly congested multiplex CARS spectra of sucrose, fructose and glucose. This novel procedures enables extraction of vibrational information from multiplex CARS data without the use of a priori information of the sample.

  14. Photocatalytic degradation of organic reactive dyes over MnTiO3/TiO2 heterojunction composites under UV-visible irradiation.

    PubMed

    Sivakumar, Santhanam; Selvaraj, Ayyasamy; Ramasamy, Anaipalayam Kandasamy

    2013-01-01

    In this study, the photocatalytic degradation of organic reactive dyes have been investigated using MnTiO3/TiO2 heterojunction composites in the presence of electron acceptors under UV-Visible light irradiation. This MnTiO3/TiO2 heterojunction composites were prepared by annealing different mass ratios of pyrophanite MnTiO3 (3-11 wt%) and TiO2 at 300°C. All the MnTiO3/TiO2 heterojunction composites were characterized by spectral techniques like X-ray diffraction (XRD), scanning electron microscope (SEM) and diffused reflectance UV-visible spectroscopic analysis (DRS). Among them, 9 wt% MnTiO3/TiO2 heterojunction composites exhibited higher photocatalytic activity for the degradation of Reactive Blue 4 (RB 4). The photocatalytic efficiency of 9 wt% MnTiO3/TiO2 heterojunction composites was further enhanced by the addition of substantial amount of electron acceptors like hydrogen peroxide (H2O2) and ammonium peroxydisulfate ([NH4]2S2O8). The presence of oxidants (electron acceptors) facilitates the fast degradation of dye solution even in higher concentration upto 200 mg/L. The photocatalytic activity of MnTiO3/TiO2 heterojunction composites was also studied for the degradation of other four different structured reactive dyes. The extent of mineralization of these organic reactive dyes during photocatalytic degradation was estimated from COD analysis. MnTiO3/TiO2 heterojunction composites was also found to have good photostability in the presence of oxidants. PMID:23848842

  15. Assessment of the stratospheric NO2 column using long-term ground-based UV-visible and satellite nadir observations

    NASA Astrophysics Data System (ADS)

    Pinardi, Gaia; Van Roozendael, Michel; Lambert, Jean-Christopher; Hendrick, Francois; Granville, José; Tack, Frederik; Goutail, Florence; Pommereau, Jean-Pierre; Pazmino, Andrea; Wittrock, Folkard; Richter, Andreas; Wagner, Thomas; Gu, Myojeong; Friess, Udo; Navarro, Monica; Puentedura, Olga

    2015-04-01

    Zenith-sky UV-visible instruments have been used to monitor stratospheric NO2 columns from pole to pole for more than 2 decades, as part of the Network for the Detection of Atmospheric Composition Change (NDACC). Long-term monitoring and fit-for-purpose data quality are essential commitments of the network. Recently, recommendations were made for a better harmonization of the retrieval of NO2 stratospheric vertical columns (Van Roozendael and Hendrick 2012, http://ndacc-uvvis-wg.aeronomie.be/tools/NDACC_UVVIS-WG_NO2settings_v4.pdf). Those include, in addition to the use of harmonized SCD settings, a common approach to the air-mass factor (AMF) calculation, based on pre-calculated look-up tables of climatological AMFs resolved in latitude, time, wavelength, surface albedo, solar zenith angle and station altitude. The impact of the NDACC recommendations on the quality of the zenith-sky UV-visible stratospheric NO2 columns is first illustrated based on 10 SAOZ (Système d'Analyse par Observations Zénithales) instruments deployed from the Arctic to the Antarctic. The long-term time-series of SAOZ and other ground-based NDACC zenith-sky measurements are then used in synergy with data from an ensemble of satellite UV-vis nadir sensors (GOME-2, SCIAMACHY and OMI), for characterising the stratospheric NO2 columns on the global scale. Appropriate photochemical state matching is applied whenever necessary to combine/compare the different data sets. Results are interpreted in terms of ground-based network data homogeneity, and accuracy, consistency and long-term stability of space-borne stratospheric NO2 columns. The consistency with previously published studies including stratospheric NO2 column measurements from limb sensors such as MIPAS and SCIAMACHY is also discussed. These quality-assessed ground-based and satellite data sets offer new perspectives for the analysis of the variability and trends of stratospheric NO2 at the global scale.

  16. Quantitative near infra-red spectroscopy of massive stars

    NASA Astrophysics Data System (ADS)

    Stap, F. A.; Sana, H.; de Koter, A.

    2011-12-01

    Interest in near infra-red spectroscopy of massive stars has increased dramatically over the last decades, as it offers the possibility to analyze stars embedded in dusty star forming regions and near the Galactic center. We present an analysis of both high resolution optical and, separately, high resolution VLT/CRIRES near-IR spectra in the J, H, K and L-band of nearby dwarf O-type stars. Applying a genetic fitting algorithm approach using state-of-the-art FASTWIND non-LTE atmospheres, we present a comparison of the stellar and wind properties as derived from these two spectral regimes. In this approach we retrieve the effective temperature to within a sub-type and the surface gravity to within 0.2 dex, but find a discrepancy in the mass-loss rates of 0.2 up to 1.0 dex. We find that He II 1012 nm and Brackett-? lines do not yield consistent mass-loss estimates, the former producing much lower values than H?, while Brackett-? and H? are consistent.

  17. Intramyocardial oxygen transport by quantitative diffuse reflectance spectroscopy in calves

    NASA Astrophysics Data System (ADS)

    Lindbergh, Tobias; Larsson, Marcus; Szabó, Zoltán; Casimir-Ahn, Henrik; Strömberg, Tomas

    2010-03-01

    Intramyocardial oxygen transport was assessed during open-chest surgery in calves by diffuse reflectance spectroscopy using a small intramuscular fiber-optic probe. The sum of hemo- and myoglobin tissue fraction and oxygen saturation, the tissue fraction and oxidation of cytochrome aa3, and the tissue fraction of methemoglobin were estimated using a calibrated empirical light transport model. Increasing the oxygen content in the inhaled gas, 21%-50%-100%, in five calves (group A) gave an increasing oxygen saturation of 19+/-4%, 24+/-5%, and 28+/-8% (p<0.001, ANOVA repeated measures design) and mean tissue fractions of 1.6% (cytochrome aa3) and 1.1% (hemo- and myoglobin). Cardiac arrest in two calves gave an oxygen saturation lower than 5%. In two calves (group B), a left ventricular assistive device (LVAD pump) was implanted. Oxygen saturation in group B animals increased with LVAD pump speed (p<0.001, ANOVA) and with oxygen content in inhaled gas (p<0.001, ANOVA). The cytochrome aa3 oxidation level was above 96% in both group A and group B calves, including the two cases involving cardiac arrest. In conclusion, the estimated tissue fractions and oxygenation/oxidation levels of the myocardial chromophores during respiratory and hemodynamic provocations were in agreement with previously presented results, demonstrating the potential of the method.

  18. Quantitative Analysis of Panax ginseng by FT-NIR Spectroscopy.

    PubMed

    Xu, Xin-Fang; Nie, Li-Xing; Pan, Li-Li; Hao, Bian; Yuan, Shao-Xiong; Lin, Rui-Chao; Bu, Hai-Bo; Wang, Dan; Dong, Ling; Li, Xiang-Ri

    2014-01-01

    Near-infrared spectroscopy (NIRS), a rapid and efficient tool, was used to determine the total amount of nine ginsenosides in Panax ginseng. In the study, the regression models were established using multivariate regression methods with the results from conventional chemical analytical methods as reference values. The multivariate regression methods, partial least squares regression (PLSR) and principal component regression (PCR), were discussed and the PLSR was more suitable. Multiplicative scatter correction (MSC), second derivative, and Savitzky-Golay smoothing were utilized together for the spectral preprocessing. When evaluating the final model, factors such as correlation coefficient (R (2)) and the root mean square error of prediction (RMSEP) were considered. The final optimal results of PLSR model showed that root mean square error of prediction (RMSEP) and correlation coefficients (R (2)) in the calibration set were 0.159 and 0.963, respectively. The results demonstrated that the NIRS as a new method can be applied to the quality control of Ginseng Radix et Rhizoma. PMID:24883224

  19. Quantitative reflectance spectroscopy of buddingtonite from the Cuprite mining district, Nevada

    SciTech Connect

    Felzer, B.; Hauff, P.; Goetz, A.F.H. [Univ. of Colorado, Boulder, CO (United States)] [Univ. of Colorado, Boulder, CO (United States)

    1994-02-01

    Buddingtonite, an ammonium-bearing feldspar diagnostic of volcanic-hosted alteration, can be identified and, in some cases, quantitatively measured using short-wave infrared (SWIR) reflectance spectroscopy. In this study over 200 samples from Cuprite, Nevada, were evaluated by X ray diffraction, chemical analysis, scanning electron microscopy, and SWIR reflectance spectroscopy with the objective of developing a quantitative remote-sensing technique for rapid determination of the amount of ammonium or buddingtonite present, and its distribution across the site. Based upon the Hapke theory of radiative transfer from particulate surfaces, spectra from quantitative, physical mixtures were compared with computed mixture spectra. We hypothesized that the concentration of ammonium in each sample is related to the size and shape of the ammonium absorption bands and tested this hypothesis for samples of relatively pure buddingtonite. We found that the band depth of the 2.12-micron NH4 feature is linearly related to the NH4 concentration for the Cuprite buddingtonite, and that the relationship is approximately exponential for a larger range of NH4 concentrations. Associated minerals such as smectite and jarosite suppress the depth of the 2.12-micron NH4 absorption band. Quantitative reflectance spectroscopy is possible when the effects of these associated minerals are also considered.

  20. Electrical and optical spectroscopy for quantitative screening of hepatic steatosis in donor livers

    NASA Astrophysics Data System (ADS)

    McLaughlin, B. L.; Wells, A. C.; Virtue, S.; Vidal-Puig, A.; Wilkinson, T. D.; Watson, C. J. E.; Robertson, P. A.

    2010-11-01

    Macro-steatosis in deceased donor livers is increasingly prevalent and is associated with poor or non-function of the liver upon reperfusion. Current assessment of the extent of steatosis depends upon the macroscopic assessment of the liver by the surgeon and histological examination, if available. In this paper we demonstrate electrical and optical spectroscopy techniques which quantitatively characterize fatty infiltration in liver tissue. Optical spectroscopy showed a correlation coefficient of 0.85 in humans when referenced to clinical hematoxylin and eosin (H&E) sections in 20 human samples. With further development, an optical probe may provide a comprehensive measure of steatosis across the liver at the time of procurement.

  1. Fluorescence Fluctuation Spectroscopy Enables Quantitative Imaging of Single mRNAs in Living Cells

    PubMed Central

    Wu, Bin; Chao, Jeffrey A.; Singer, Robert H.

    2012-01-01

    Imaging mRNA with single-molecule sensitivity in live cells has become an indispensable tool for quantitatively studying RNA biology. The MS2 system has been extensively used due to its unique simplicity and sensitivity. However, the levels of the coat protein needed for consistent labeling of mRNAs limits the sensitivity and quantitation of this technology. Here, we applied fluorescence fluctuation spectroscopy to quantitatively characterize and enhance the MS2 system. Surprisingly, we found that a high fluorescence background resulted from inefficient dimerization of fluorescent protein (FP)-labeled MS2 coat protein (MCP). To mitigate this problem, we used a single-chain tandem dimer of MCP (tdMCP) that significantly increased the uniformity and sensitivity of mRNA labeling. Furthermore, we characterized the PP7 coat protein and the binding to its respective RNA stem loop. We conclude that the PP7 system performs better for RNA labeling. Finally, we used these improvements to study endogenous ?-actin mRNA, which has 24xMS2 binding sites inserted into the 3? untranslated region. The tdMCP-FP allowed uniform RNA labeling and provided quantitative measurements of endogenous mRNA concentration and diffusion. This work provides a foundation for quantitative spectroscopy and imaging of single mRNAs directly in live cells. PMID:22735544

  2. A study of the 42CrMo4 steel surface by quantitative XPS electron spectroscopy

    NASA Astrophysics Data System (ADS)

    Flori, M.; Gruzza, B.; Bideux, L.; Monier, G.; Robert-Goumet, C.

    2008-05-01

    Quantitative X-ray photoelectron spectroscopy was used to characterize the native oxide film formed on 42CrMo4 steel surface by air exposure in normal conditions. In order to determine the thickness and composition of the oxide layer we have used a stacking layer model together with experimental XPS sputtering depth profiling. At a nanoscale study, to obtain quantitative results one must take into account fundamental parameters like the attenuation depth of photoelectrons. We have found that both lepidocrocit (?-FeOOH) and magnetite (Fe 3O 4) were present and the total thickness of the oxide layer was 16 monolayers.

  3. P-31 magnetic resonance spectroscopy and near-infrared spectroscopy provide unique quantitative data for evaluation of exercising muscles

    NASA Astrophysics Data System (ADS)

    Park, Jane H.; Golwyn, Daniel; Olsen, Nancy J.; Newman, John H.; Powers, Alvin C.; Davis, Beverly C.; Rader, Kara; Chance, Britton

    1994-09-01

    P-31 magnetic resonance spectroscopy (MRS) and near-infra spectroscopy (NIRS) have been used to characterize the dynamic aspects of human muscle contraction. P-31 MRS is a non- invasive method for measuring ATP, phosphocreatine (PCr), and pH in exercising muscles and thereby provides information regarding oxidative and glycolytic capacities for generating high energy phosphate compounds. NIRS evaluates kinetic changes in oxygen levels in muscles during exercise and recovery. These two methods provide unique quantitative data for studies of normal muscle contraction and for more complex investigations of muscle diseases. Non-invasive MRS and NIRS examinations are readily repeatable and yield important data for longitudinal patient evaluation and therapeutic management.

  4. Rapid quantitation of thermal oxidation products in fats and oils by 1H-NMR spectroscopy.

    PubMed

    Yang, C M; Grey, A A; Archer, M C; Bruce, W R

    1998-01-01

    This work describes the application of high-resolution proton nuclear magnetic resonance (1H-NMR) spectroscopy to the study of the thermal peroxidation of beef tallow and corn oil under standardized conditions. The approach provides a rapid, quantitative method for determining the degree of oxidation of unsaturated fatty acids in animal and vegetable fats and oils by quantitating the decreasing intensities of 1H-NMR peaks for allylic and olefinic protons in unsaturated fatty acid chains of triglycerides and the increasing peak intensities of hydroperoxide and saturated and alpha, beta-unsaturated aldehydic protons in relation to the less labile protons in the triglyceride molecule. Two-dimensional correlation spectroscopy analysis of highly oxidized beef tallow (180 degrees C for 24 h) suggested that the unsaturated aldehydes that persisted were apparently associated with carboxy groups. PMID:9507515

  5. Real time high frequency monitoring of water quality in river streams using a UV-visible spectrometer: interest, limits and consequences for monitoring strategies

    NASA Astrophysics Data System (ADS)

    Faucheux, Mikaël; Fovet, Ophélie; Gruau, Gérard; Jaffrézic, Anne; Petitjean, Patrice; Gascuel-Odoux, Chantal; Ruiz, Laurent

    2013-04-01

    Stream water chemistry is highly variable in space and time, therefore high frequency water quality measurement methods are likely to lead to conceptual advances in the hydrological sciences. Sub-daily data on water quality improve the characterization of pollutant sources and pathways during flood events as well as during long-term periods [1]. However, real time, high frequency monitoring devices needs to be properly calibrated and validated in real streams. This study analyses data from in situ monitoring of a stream water quality. During two hydrological years (2010-11, 2011-12), a submersible UV-visible spectrometer (Scan Spectrolyser) was used for surface water quality measurement at the outlet of a headwater catchment located at Kervidy-Naizin, Western France (AgrHys long-term hydrological observatory, http://www.inra.fr/ore_agrhys/). The spectrometer is reagentless and equipped with an auto-cleaning system. It allows real time, in situ and high frequency (20 min) measurements and uses a multiwavelengt spectral (200-750 nm) for simultaneous measurement of nitrate, dissolved organic carbon (DOC) and total suspended solids (TSS). A global calibration based on a PLS (Partial Least Squares) regression is provided by the manufacturer as default configuration of the UV-visible spectrometer. We carried out a local calibration of the spectrometer based on nitrates and DOC concentrations analysed in the laboratory from daily manual sampling and sub-daily automatic sampling of flood events. TSS results are compared with 15 min turbidity records from a continuous turdidimeter (Ponsel). The results show a good correlation between laboratory data and spectrometer data both during basis flows periods and flood events. However, the local calibration gives better results than the global one. Nutrient fluxes estimates based on high and different low frequency time series (daily to monthly) are compared to discuss the implication for environmental monitoring strategies. Such monitoring methods can therefore be interesting for designing monitoring strategy of environmental observatory and provide dense time series likely to highlight patterns or trends using appropriate approaches such as spectral analysis [2]. 1. Wade, A.J. et al., HESS Discuss., 2012. 9(5), p.6458- 6506. 2. Aubert, A. et al., submitted to EGU 2013-4745 vol. 15.

  6. Self-calibrated quantitative elemental analysis by laser-induced plasma spectroscopy: application to pigment analysis

    Microsoft Academic Search

    Ilaria Borgia; Lucia M. F Burgio; Michela Corsi; Roberta Fantoni; Vincenzo Palleschi; Azenio Salvetti; Maria Cristina Squarcialupi; Elisabetta Tognoni

    2000-01-01

    A new laser-based spectroscopic technique, called calibration-free LIPS (laser-induced plasma spectroscopy), is proposed for fast and precise elemental analysis in the field of cultural heritage conservation and study. Quantitative stratigraphic results, obtained by CF-LIPS on ancient Roman frescoe samples, are shown. The application of this calibration-free procedure frees the LIPS technique from the need of reference samples or an internal

  7. Quantitative determination of element concentrations in industrial oxide materials by laser-induced breakdown spectroscopy

    Microsoft Academic Search

    B. Praher; R. Rössler; E. Arenholz; J. Heitz; J. D. Pedarnig

    Calibration-free laser-induced breakdown spectroscopy (CF-LIBS) method is employed for quantitative determination of oxide\\u000a concentrations in multi-component materials. Industrial oxide materials from steel industry are laser ablated in air, and\\u000a the optical plasma emission is collected by spectrometers and gated detectors. The temperature and electron number density\\u000a of laser-induced plasma are determined from measured LIBS spectra. Emission lines of aluminium (Al),

  8. Quantitative Detection of Pharmaceuticals Using a Combination of Paper Microfluidics and Wavelength Modulated Raman Spectroscopy

    PubMed Central

    Craig, Derek; Mazilu, Michael; Dholakia, Kishan

    2015-01-01

    Raman spectroscopy has proven to be an indispensable technique for the identification of various types of analytes due to the fingerprint vibration spectrum obtained. Paper microfluidics has also emerged as a low cost, easy to fabricate and portable approach for point of care testing. However, due to inherent background fluorescence, combining Raman spectroscopy with paper microfluidics is to date an unmet challenge in the absence of using surface enhanced mechanisms. We describe the first use of wavelength modulated Raman spectroscopy (WMRS) for analysis on a paper microfluidics platform. This study demonstrates the ability to suppress the background fluorescence of the paper using WMRS and the subsequent implementation of this technique for pharmaceutical analysis. The results of this study demonstrate that it is possible to discriminate between both paracetamol and ibuprofen, whilst, also being able to detect the presence of each analyte quantitatively at nanomolar concentrations. PMID:25938464

  9. Quantitative Determination of Carthamin in Carthamus Red by 1H-NMR Spectroscopy.

    PubMed

    Yoshida, Takamitsu; Terasaka, Kazuyoshi; Kato, Setsuko; Bai, Fan; Sugimoto, Naoki; Akiyama, Hiroshi; Yamazaki, Takeshi; Mizukami, Hajime

    2013-01-01

    Carthamus Red is a food colorant prepared from the petals of Carthamus tinctorius (Asteraceae) whose major pigment is carthamin. Since an authentic carthamin standard is difficult to obtain commercially for the preparation of calibration curves in HPLC assays, we applied (1)H-NMR spectroscopy to the quantitative determination of carthamin in commercial preparations of Carthamus Red. Carthamus Red was repeatedly extracted in methanol and the extract was dissolved in pyridine-d(5) containing hexamethyldisilane (HMD) prior to (1)H-NMR spectroscopic analysis. The carthamin contents were calculated from the ratios of singlet signal intensities at approximately ?: 9.3 derived from H-16 of carthamin to those of the HMD signal at ?: 0. The integral ratios exhibited good repeatability among NMR spectroscopic analyses. Both the intra-day and inter-day assay variations had coefficients of variation of <5%. Based on the coefficient of absorption, the carthamin contents of commercial preparations determined by (1)H-NMR spectroscopy correlated well with those determined by colorimetry, although the latter were always approximately 1.3-fold higher than the former, irrespective of the Carthamus Red preparations. In conclusion, the quantitative (1)H-NMR spectroscopy used in the present study is simple and rapid, requiring no carthamin standard for calibration. After HMD concentration has been corrected using certified reference materials, the carthamin contents determined by (1)H-NMR spectroscopy are System of Units (SI)-traceable. PMID:24436958

  10. Quantitative characterisation of historic paper using THz spectroscopy and multivariate data analysis

    NASA Astrophysics Data System (ADS)

    Trafela, Tanja; Mizuno, Maya; Fukunaga, Kaori; Strli?, Matija

    2013-04-01

    THz spectroscopy in the time domain was explored in combination with multivariate data analysis, for quantitative determination of chemical and mechanical properties of historic paper, such as lignin content, tensile strength, and ash content. Using partial least squares (PLS) regression, it was shown that quantitative prediction of the material properties is possible, which indicates the potential of THz spectroscopy for chemical characterisation of complex organic materials of natural origin. In addition, the results demonstrate that THz spectra and PLS loading weights for lignin content differ significantly, which leads to the conclusion that THz spectra of composite macromolecular materials do not represent sums of spectra of the individual components. This supports the premise that THz spectra reflect intermolecular interactions. The study was carried out using 250 historical paper samples from the sixteenth century to present. Although the measurements were performed in vacuum to improve the quality of spectra, THz spectroscopy is in principle non-destructive. This research therefore reinforces the role of THz spectroscopy in characterisation of valuable historic materials, where invasive analysis is often not possible.

  11. Evolution of the dust and water ice plume components as observed by the LCROSS visible camera and UV-visible spectrometer

    NASA Astrophysics Data System (ADS)

    Heldmann, Jennifer L.; Lamb, Justin; Asturias, Daniel; Colaprete, Anthony; Goldstein, David B.; Trafton, Laurence M.; Varghese, Philip L.

    2015-07-01

    The LCROSS (Lunar Crater Observation and Sensing Satellite) impacted the Cabeus crater near the lunar South Pole on 9 October 2009 and created an impact plume that was observed by the LCROSS Shepherding Spacecraft. Here we analyze data from the ultraviolet-visible spectrometer and visible context camera aboard the spacecraft. We use these data to constrain a numerical model to understand the physical evolution of the resultant plume. The UV-visible light curve peaks in brightness 18 s after impact and then decreases in radiance but never returns to the pre-impact radiance value for the ?4 min of observation by the Shepherding Spacecraft. The blue:red spectral ratio increases in the first 10 s, decreases over the following 50 s, remains constant for approximately 150 s, and then begins to increase again ?180 s after impact. Constraining the modeling results with spacecraft observations, we conclude that lofted dust grains remained suspended above the lunar surface for the entire 250 s of observation after impact. The impact plume was composed of both a high angle spike and low angle plume component. Numerical modeling is used to evaluate the relative effects of various plume parameters to further constrain the plume properties when compared with the observational data. Dust particle sizes lofted above the lunar surface were micron to sub-micron in size. Water ice particles were also contained within the ejecta cloud and simultaneously photo-dissociated and sublimated after reaching sunlight.

  12. Preparation and characterizations of SnO2 nanopowder and spectroscopic (FT-IR, FT-Raman, UV-Visible and NMR) analysis using HF and DFT calculations

    NASA Astrophysics Data System (ADS)

    Ayeshamariam, A.; Ramalingam, S.; Bououdina, M.; Jayachandran, M.

    2014-01-01

    In this work, pure and singe phase SnO2 Nano powder is successfully prepared by simple sol-gel combustion route. The photo luminescence and XRD measurements are made and compared the geometrical parameters with calculated values. The FT-IR and FT-Raman spectra are recorded and the fundamental frequencies are assigned. The optimized parameters and the frequencies are calculated using HF and DFT (LSDA, B3LYP and B3PW91) theory in bulk phase of SnO2 and are compared with its Nano phase. The vibrational frequency pattern in nano phase gets realigned and the frequencies are shifted up to higher region of spectra when compared with bulk phase. The NMR and UV-Visible spectra are simulated and analyzed. Transmittance studies showed that the HOMO-LUMO band gap (Kubo gap) is reduced from 3.47 eV to 3.04 eV while it is heated up to 800 °C. The Photoluminescence spectra of SnO2 powder showed a peak shift towards lower energy side with the change of Kubo gap from 3.73 eV to 3.229 eV for as-prepared and heated up to 800 °C.

  13. Protonation/deprotonation process of Emodin in aqueous solution and pKa determination: UV/Visible spectrophotometric titration and quantum/molecular mechanics calculations

    NASA Astrophysics Data System (ADS)

    da Cunha, Antonio R.; Duarte, Evandro L.; Lamy, M. Teresa; Coutinho, Kaline

    2014-08-01

    We combined theoretical and experimental studies to elucidate the important deprotonation process of Emodin in water. We used the UV/Visible spectrophotometric titration curves to obtain its pKa values, pKa1 = 8.0 ± 0.1 and pKa2 = 10.9 ± 0.2. Additionally, we obtained the pKa values of Emodin in the water-methanol mixture (1:3v/v). We give a new interpretation of the experimental data, obtaining apparent pKa1 = 6.2 ± 0.1, pKa2 = 8.3 ± 0.1 and pKa3 > 12.7. Performing quantum mechanics calculations for all possible deprotonation sites and tautomeric isomers of Emodin in vacuum and in water, we identified the sites of the first and second deprotonation. We calculated the standard deprotonation free energy of Emodin in water and the pKa1, using an explicit model of the solvent, with Free Energy Perturbation theory in Monte Carlo simulations obtaining, ?Gaq = 12.1 ± 1.4 kcal/mol and pKa1 = 8.7 ± 0.9. With the polarizable continuum model for the solvent, we obtained ?Gaq = 11.6 ± 1.0 kcal/mol and pKa1 = 8.3 ± 0.7. Both solvent models gave theoretical results in very good agreement with the experimental values.

  14. UV-visible and infrared absorption spectra of gamma irradiated CuO-doped lithium phosphate, lead phosphate and zinc phosphate glasses: A comparative study

    NASA Astrophysics Data System (ADS)

    ElBatal, H. A.; Abdelghany, A. M.; ElBatal, F. H.; ElBadry, Kh. M.; Moustaffa, F. A.

    2011-10-01

    Undoped and CuO-doped lithium phosphate, lead phosphate and zinc phosphate glasses were prepared. UV-visible and infrared absorption spectra of the prepared samples were measured before and after successive gamma irradiation. Experimental optical spectra of the undoped samples reveal strong UV absorption bands, which are attributed to the presence of trace iron impurities in both the lithium and zinc phosphate glasses while the lead phosphate glass exhibits broad UV bands due to combined absorption of trace iron impurities and divalent lead ions. The CuO-doped glasses reveal an extra broad visible band due to Cu 2+ ions in octahedral coordination. The effects of gamma irradiation have been analyzed for both the sharing of all constituent components including trace iron impurities. Infrared absorption spectra of the prepared samples were investigated by the KBr disk technique. The FTIR spectra reveal main characteristic absorption bands due to different phosphate groups. The IR spectra are observed to be slightly affected by the increase of CuO in the doping level (0.2-3%) indicating the stability of the main network units.

  15. Preparation and characterizations of SnO2 nanopowder and spectroscopic (FT-IR, FT-Raman, UV-Visible and NMR) analysis using HF and DFT calculations.

    PubMed

    Ayeshamariam, A; Ramalingam, S; Bououdina, M; Jayachandran, M

    2014-01-24

    In this work, pure and singe phase SnO2 Nano powder is successfully prepared by simple sol-gel combustion route. The photo luminescence and XRD measurements are made and compared the geometrical parameters with calculated values. The FT-IR and FT-Raman spectra are recorded and the fundamental frequencies are assigned. The optimized parameters and the frequencies are calculated using HF and DFT (LSDA, B3LYP and B3PW91) theory in bulk phase of SnO2 and are compared with its Nano phase. The vibrational frequency pattern in nano phase gets realigned and the frequencies are shifted up to higher region of spectra when compared with bulk phase. The NMR and UV-Visible spectra are simulated and analyzed. Transmittance studies showed that the HOMO-LUMO band gap (Kubo gap) is reduced from 3.47 eV to 3.04 eV while it is heated up to 800°C. The Photoluminescence spectra of SnO2 powder showed a peak shift towards lower energy side with the change of Kubo gap from 3.73 eV to 3.229 eV for as-prepared and heated up to 800°C. PMID:24184584

  16. Evaluation of Hydrodynamic Chromatography Coupled with UV-Visible, Fluorescence and Inductively Coupled Plasma Mass Spectrometry Detectors for Sizing and Quantifying Colloids in Environmental Media

    PubMed Central

    Philippe, Allan; Schaumann, Gabriele E.

    2014-01-01

    In this study, we evaluated hydrodynamic chromatography (HDC) coupled with inductively coupled plasma mass spectrometry (ICP-MS) for the analysis of nanoparticles in environmental samples. Using two commercially available columns (Polymer Labs-PDSA type 1 and 2), a set of well characterised calibrants and a new external time marking method, we showed that flow rate and eluent composition have few influence on the size resolution and, therefore, can be adapted to the sample particularity. Monitoring the agglomeration of polystyrene nanoparticles over time succeeded without observable disagglomeration suggesting that even weak agglomerates can be measured using HDC. Simultaneous determination of gold colloid concentration and size using ICP-MS detection was validated for elemental concentrations in the ppb range. HDC-ICP-MS was successfully applied to samples containing a high organic and ionic background. Indeed, online combination of UV-visible, fluorescence and ICP-MS detectors allowed distinguishing between organic molecules and inorganic colloids during the analysis of Ag nanoparticles in synthetic surface waters and TiO2 and ZnO nanoparticles in commercial sunscreens. Taken together, our results demonstrate that HDC-ICP-MS is a flexible, sensitive and reliable method to measure the size and the concentration of inorganic colloids in complex media and suggest that there may be a promising future for the application of HDC in environmental science. Nonetheless the rigorous measurements of agglomerates and of matrices containing natural colloids still need to be studied in detail. PMID:24587393

  17. N-hydroxyguanidines as new heme ligands: UV-visible, EPR, and resonance Raman studies of the interaction of various compounds bearing a C=NOH function with microperoxidase-8.

    PubMed

    Lefevre-Groboillot, D; Dijols, S; Boucher, J L; Mahy, J P; Ricoux, R; Desbois, A; Zimmermann, J L; Mansuy, D

    2001-08-21

    Interaction between microperoxidase-8 (MP8), a water-soluble hemeprotein model, and a wide range of N-aryl and N-alkyl N'-hydroxyguanidines and related compounds has been investigated using UV-visible, EPR, and resonance Raman spectroscopies. All the N-hydroxyguanidines studied bind to the ferric form of MP8 with formation of stable low-spin iron(III) complexes characterized by absorption maxima at 405, 535, and 560 nm. The complex obtained with N-(4-methoxyphenyl) N'-hydroxyguanidine exhibits EPR g-values at 2.55, 2.26, and 1.86. The resonance Raman (RR) spectrum of this complex is also in agreement with an hexacoordinated low-spin iron(III) structure. The dissociation constants (K(s)) of the MP8 complexes with mono- and disubstituted N-hydroxyguanidines vary between 15 and 160 microM at pH 7.4. Amidoximes also form low-spin iron(III) complexes of MP8, although with much larger dissociation constants. Under the same conditions, ketoximes, aldoximes, methoxyguanidines, and guanidines completely fail to form such complexes with MP8. The K(s) values of the MP8-N-hydroxyguanidine complexes decrease as the pH of the solution is increased, and the affinity of the N-hydroxyguanidines toward MP8 increases with the pK(a) of these ligands. Altogether these results show that compounds involving a -C(NHR)=NOH moiety act as good ligands of MP8-Fe(III) with an affinity that depends on the electron-richness of this moiety. The analysis of the EPR spectrum of the MP8-N-hydroxyguanidine complexes according to Taylor's equations shows a strong axial distortion of the iron, typical of those observed for hexacoordinated heme-Fe(III) complexes with at least one pi donor axial ligand (HO(-), RO(-), or RS(-)). These data strongly suggest that N-hydroxyguanidines bind to MP8 iron via their oxygen atom after deprotonation or weakening of their O-H bond. It thus seems that N-hydroxyguanidines could constitute a new class of strong ligands for hemeproteins and iron(III)-porphyrins. PMID:11502185

  18. Characterization of prepared In2O3 thin films: The FT-IR, FT-Raman, UV-Visible investigation and optical analysis

    NASA Astrophysics Data System (ADS)

    Panneerdoss, I. Joseph; Jeyakumar, S. Johnson; Ramalingam, S.; Jothibas, M.

    2015-08-01

    In this original work, the Indium oxide (In2O3) thin film is deposited cleanly on microscope glass substrate at different temperatures by spray pyrolysis technique. The physical properties of the films are characterized by XRD, SEM, AFM and AFM measurements. The spectroscopic investigation has been carried out on the results of FT-IR, FT-Raman and UV-Visible. XRD analysis exposed that the structural transformation of films from stoichiometric to non-stoichiometric orientation of the plane vice versa and also found that, the film is polycrystalline in nature having cubic crystal structure with a preferred grain orientation along (2 2 2) plane. SEM and AFM studies revealed that, the film with 0.1 M at 500 °C has spherical grains with uniform dimension. The complete vibrational analysis has been carried out and the optimized parameters are calculated using HF and DFT (CAM-B3LYP, B3LYP and B3PW91) methods with 3-21G(d,p) basis set. Furthermore, NMR chemical shifts are calculated by using the gauge independent atomic orbital (GIAO) technique. The molecular electronic properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, molecular electrostatic potential energy (MEP) analysis and Polarizability first order hyperpolarizability calculations are performed by time dependent DFT (TD-DFT) approach. The energy excitation on electronic structure is investigated and the assignment of the absorption bands in the electronic spectra of steady compound is discussed. The calculated HOMO and LUMO energies showed the enhancement of energy gap by the addition of substitutions with the base molecule. The thermodynamic properties (heat capacity, entropy, and enthalpy) at different temperatures are calculated and interpreted in gas phase.

  19. Quantitative mixture fraction measurements in combustion system via laser induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Mansour, Mohy; Imam, Hisham; Elsayed, Khaled A.; Elbaz, A. M.; Abbass, Wafaa

    2015-01-01

    Laser induced breakdown spectroscopy (LIBS) technique has been applied to quantitative mixture fraction measurements in flames. The measured spectra of different mixtures of natural gas and air are used to obtain the calibration parameters for local elemental mass fraction measurements and hence calculate the mixture fraction. The results are compared with the mixture fraction calculations based on the ratios of the spectral lines of H/N elements, H/O elements and C/(N+O) and they show good agreement within the reaction zone of the flames. Some deviations are observed outside the reaction zone. The ability of LIBS technique as a tool for quantitative mixture fraction as well as elemental fraction measurements in reacting and non-reacting of turbulent flames is feasible.

  20. Quantitative analysis of virgin coconut oil in cream cosmetics preparations using fourier transform infrared (FTIR) spectroscopy.

    PubMed

    Rohman, A; Man, Yb Che; Sismindari

    2009-10-01

    Today, virgin coconut oil (VCO) is becoming valuable oil and is receiving an attractive topic for researchers because of its several biological activities. In cosmetics industry, VCO is excellent material which functions as a skin moisturizer and softener. Therefore, it is important to develop a quantitative analytical method offering a fast and reliable technique. Fourier transform infrared (FTIR) spectroscopy with sample handling technique of attenuated total reflectance (ATR) can be successfully used to analyze VCO quantitatively in cream cosmetic preparations. A multivariate analysis using calibration of partial least square (PLS) model revealed the good relationship between actual value and FTIR-predicted value of VCO with coefficient of determination (R2) of 0.998. PMID:19783522

  1. Renal geology (quantitative renal stone analysis) by ‘Fourier transform infrared spectroscopy

    Microsoft Academic Search

    Iqbal Singh

    2008-01-01

    Aim  To prospectively determine the precise stone composition (quantitative analysis) by using infrared spectroscopy in patients\\u000a with urinary stone disease presenting to our clinic. To determine an ideal method for stone analysis suitable for use in a\\u000a clinical setting.\\u000a \\u000a \\u000a \\u000a Methods  After routine and a detailed metabolic workup of all patients of urolithiasis, stone samples of 50 patients of urolithiasis\\u000a satisfying the entry

  2. Quantitative analysis of iobitridol in an injectable preparation by 1H NMR spectroscopy.

    PubMed

    Borioni, Anna; Gostoli, Gianluca; Bossù, Elena; Sestili, Isabella

    2014-06-01

    Nuclear magnetic resonance spectroscopy was used for direct quantitative determination of iobitridol in an injectable formulation. The method was developed on a medium field strength magnet (400MHz) and validation was performed by assessing specificity, accuracy, precision, linearity, stability of samples and robustness. Validation data confirm that the method is highly appropriate for direct quantification of iobitridol in the final formulation. Moreover the method has a good potential for rapid screening analyses due to straightforward experimental setup and lack of any sample pretreatment. PMID:24531005

  3. Direct-potential-fit analysis of new infrared and UV\\/visible A 1Sigma+-X 1Sigma+ emission spectra of AgH and AgD

    Microsoft Academic Search

    Robert J. Le Roy; Dominique R. T. Appadoo; Kevin Anderson; Alireza Shayesteh; Iouli E. Gordon; Peter F. Bernath

    2005-01-01

    New high-resolution infrared and UV\\/visible spectra of 107AgH, 109AgH, 107AgD, and 109AgD have been recorded with a Fourier transform spectrometer. The new line positions are combined with published microwave and older electronic A 1Sigma+-X 1Sigma+ data and used, first in a decoupled analysis of the X state alone, and then in a global multi-isotopologue analysis which yields comprehensive descriptions of

  4. Quantitative spectral and orientational analysis in surface sum frequency generation vibrational spectroscopy (SFG-VS)

    NASA Astrophysics Data System (ADS)

    Wang, Hong-Fei; Gan, Wei; Lu, Rong; Rao, Yi; Wu, Bao-Hua

    Sum frequency generation vibrational spectroscopy (SFG-VS) has been proven to be a uniquely effective spectroscopic technique in the investigation of molecular structure and conformations, as well as the dynamics of molecular interfaces. However, the ability to apply SFG-VS to complex molecular interfaces has been limited by the ability to abstract quantitative information from SFG-VS experiments. In this review, we try to make assessments of the limitations, issues and techniques as well as methodologies in quantitative orientational and spectral analysis with SFG-VS. Based on these assessments, we also try to summarize recent developments in methodologies on quantitative orientational and spectral analysis in SFG-VS, and their applications to detailed analysis of SFG-VS data of various vapour/neat liquid interfaces. A rigorous formulation of the polarization null angle (PNA) method is given for accurate determination of the orientational parameter D = /, and comparison between the PNA method with the commonly used polarization intensity ratio (PIR) method is discussed. The polarization and incident angle dependencies of the SFG-VS intensity are also reviewed, in the light of how experimental arrangements can be optimized to effectively abstract crucial information from the SFG-VS experiments. The values and models of the local field factors in the molecular layers are discussed. In order to examine the validity and limitations of the bond polarizability derivative model, the general expressions for molecular hyperpolarizability tensors and their expression with the bond polarizability derivative model for C3v, C2v and C?v molecular groups are given in the two appendixes. We show that the bond polarizability derivative model can quantitatively describe many aspects of the intensities observed in the SFG-VS spectrum of the vapour/neat liquid interfaces in different polarizations. Using the polarization analysis in SFG-VS, polarization selection rules or guidelines are developed for assignment of the SFG-VS spectrum. Using the selection rules, SFG-VS spectra of vapour/diol, and vapour/n-normal alcohol (n˜ 1-8) interfaces are assigned, and some of the ambiguity and confusion, as well as their implications in previous IR and Raman assignment, are duly discussed. The ability to assign a SFG-VS spectrum using the polarization selection rules makes SFG-VS not only an effective and useful vibrational spectroscopy technique for interface studies, but also a complementary vibrational spectroscopy method in general condensed phase studies. These developments will put quantitative orientational and spectral analysis in SFG-VS on a more solid foundation. The formulations, concepts and issues discussed in this review are expected to find broad applications for investigations on molecular interfaces in the future.

  5. Introduction to Spectroscopy

    NSDL National Science Digital Library

    Reusch, William

    2007-08-10

    This site covers introductory material related to the analysis of small organic molecules by mass spectrometry, UV-visible, IR, and NMR spectroscopy. A concise explanation of each approach is presented with illustrations. This would be useful for those teaching organic chemistry and for others who need a review of the topic. The section on Spectroscopy Resources at the end of the site contains a list of links to additional information plus a several links to compilations of problems (and their solutions) that challenge the student to interpret NMR or IR spectra.

  6. H2o Quantitative Analysis of Transition Zone Minerals Wadsleyite and Ringwoodite By Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Novella, D.; Bolfan-Casanova, N.; Bureau, H.; Raepsaet, C.; Montagnac, G.

    2014-12-01

    Liquid H2O covers approximately 70% of the Earth's surface but it can also be incorporated as OH- groups in nominally anhydrous minerals (NAMs) that constitute the Earth's mantle, as observed in peridotitic xenoliths. The presence of even trace amounts (ppm wt) of hydrogen in mantle minerals strongly affect the physical, chemical and rheological properties of the mantle. The Earth's transition zone (410 to 660 km depth) is particularly important in this regard since it can store large amounts of H2O (wt%) as shown by experiments and recently by a natural sample. Addressing the behavior of H2O at high depths and its potential concentration in mantle NAMs is therefore fundamental to fully comprehend global-scale processes such as plate tectonics and magmatism. We developed an innovative technique to measure the H2O content of main transition zone NAMs wadsleyite and ringwoodite by Raman spectroscopy. This technique allows to use a beam of 1-3 µm size to measure small samples that are typical for high pressure natural and synthetic specimens. High pressure polyphasic samples are indeed very challenging to be measured in terms of H2O content by the routinely used Fourier transform infra-red (FTIR) spectroscopy and ion probe mass spectroscopy analyses, making the Raman approach a valid alternative. High quality crystals of wadsleyite and ringwoodite were synthesized at high pressure and temperature in a multi-anvil press and analyzed by Raman and FTIR spectroscopy as well as elastic recoil detection analyses (ERDA) which is an absolute, standard-free technique. We will present experimental data that allow to apply Raman spectroscopy to the determination of H2O content of the most abundant minerals in the transition zone. The data gathered in this study will also permit to investigate the absorption coefficients of wadsleyite and ringwoodite that are employed in FTIR quantitative analyses.

  7. Qualitative and quantitative analysis of calcium-based microfillers using terahertz spectroscopy and imaging.

    PubMed

    Abina, Andreja; Puc, Uroš; Jegli?, Anton; Prah, Jana; Venckevi?ius, Rimvydas; Kašalynas, Irmantas; Valušis, Gintaras; Zidanšek, Aleksander

    2015-10-01

    In different industrial applications, several strictly defined parameters of calcium-based microfillers such as average particle size, particle size distribution, morphology, specific surface area, polymorphism and chemical purity, play a key role in the determination of its usefulness and effectiveness. Therefore, an analytical tool is required for rapid and non-destructive characterization of calcium-based microfillers during the synthesis process or before its use in a further manufacturing process. Since spectroscopic techniques are preferred over microscopy and thermogravimetry, particularly due to its non-destructive nature and short analysis time, we applied terahertz (THz) spectroscopy to analyse calcite microfillers concentration in polymer matrix, its granulation and chemical treatment. Based on the analysis of peak absorbance amplitude, peak frequency position, and the appearance of additional spectral features, quantitative and qualitative analysis was successfully achieved. In addition, THz imaging was also applied for both quantitative and qualitative analysis of calcium-based microfillers. By using spatial distribution map, the inhomogeneity in concentration of calcium carbonate in polymer matrix was characterized. Moreover, by THz spectroscopy and imaging different calcium compounds were detected in binary mixtures. Finally, we demonstrated that the applied spectroscopic technique offers valuable results and can be, in combination with other spectroscopic and microscopic techniques, converted to a powerful rapid analytical tool. PMID:26078145

  8. Quantitative analyses of tartaric acid based on terahertz time domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Cao, Binghua; Fan, Mengbao

    2010-10-01

    Terahertz wave is the electromagnetic spectrum situated between microwave and infrared wave. Quantitative analysis based on terahertz spectroscopy is very important for the application of terahertz techniques. But how to realize it is still under study. L-tartaric acid is widely used as acidulant in beverage, and other food, such as soft drinks, wine, candy, bread and some colloidal sweetmeats. In this paper, terahertz time-domain spectroscopy is applied to quantify the tartaric acid. Two methods are employed to process the terahertz spectra of different samples with different content of tartaric acid. The first one is linear regression combining correlation analysis. The second is partial least square (PLS), in which the absorption spectra in the 0.8-1.4THz region are used to quantify the tartaric acid. To compare the performance of these two principles, the relative error of the two methods is analyzed. For this experiment, the first method does better than the second one. But the first method is suitable for the quantitative analysis of materials which has obvious terahertz absorption peaks, while for material which has no obvious terahertz absorption peaks, the second one is more appropriate.

  9. Method for quantitative determination of spatial polymer distribution in alginate beads using Raman spectroscopy.

    PubMed

    Heinemann, Matthias; Meinberg, Holger; Büchs, Jochen; Koss, Hans-Jürgen; Ansorge-Schumacher, Marion B

    2005-03-01

    A new method based on Raman spectroscopy is presented for non-invasive, quantitative determination of the spatial polymer distribution in alginate beads of approximately 4 mm diameter. With the experimental setup, a two-dimensional image is created along a thin measuring line through the bead comprising one spatial and one spectral dimension. For quantitative analysis of the Raman spectra, the method of indirect hard modeling was applied to make use of the information contained in the entire recorded spectra. For quantification of the alginate signals from within the beads, a calibration curve acquired from sodium alginate solutions was used after it was shown that only negligible differences occur between signals from alginate solutions and alginate gels. The distribution of alginate over the bead gel matrix was acquired with high spatial (51 microm) and time (12 s) resolution. The inhomogeneous distribution obtained using the new measuring technique is qualitatively in excellent agreement with data from the literature. In contrast to known measuring techniques, correct quantitative information about the spatial polymer distribution within the matrix was derived. It gave an alginate mass fraction of approximately 0.045 g/g at the edges and 0.02 g/g in the center of the beads. Next to the determination of mere polymer concentrations, the excellent time resolution of the presented method will enable investigation of the dynamic process of gel formation and it will also serve as a basis for investigation of mass transfer of small diffusing molecules in alginate matrices. PMID:15901307

  10. Toward quantitative deuterium analysis with laser-induced breakdown spectroscopy using atmospheric-pressure helium gas

    SciTech Connect

    Hedwig, Rinda; Lie, Zener Sukra; Kurniawan, Koo Hendrik [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Chumakov, Alexander Nikitich [B. I. Stepanov Institute of Physics of the National Academy of Sciences of Belarus, 68 Nezalezhnastsi Ave., Minsk 220072 (Belarus); Kagawa, Kiichiro [Department of Physics, Faculty of Education and Regional Studies, Fukui University, 9-1 bunkyo 3-chome, Fukui 910-8507 (Japan); Tjia, May On [Physics of Magnetism and Photonics Research Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia)

    2010-01-15

    An experimental study has been carried out for the development of quantitative deuterium analysis using the neodymium doped yttrium aluminum garnet laser-induced breakdown spectroscopy (LIBS) with atmospheric pressure surrounding He gas by exploring the appropriate experimental condition and special sample cleaning technique. The result demonstrates the achievement of a full resolution between the D and H emission lines from zircaloy-4 samples, which is prerequisite for the desired quantitative analysis. Further, a linear calibration line with zero intercept was obtained for the emission intensity of deuterium from a number of zircaloy samples doped with predetermined concentrations of deuterium. The result is obtained by setting a +4 mm defocusing position for the laser beam, 6 {mu}s detection gating time, and 7 mm imaging position of the plasma for the detection, which is combined with a special procedure of repeated laser cleaning of the samples. This study has thus provided the basis for the development of practical quantitative deuterium analysis by LIBS.

  11. Quantitative detection of astaxanthin and cantaxanthin in Atlantic salmon by resonance Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Ermakov, Igor V.; Ermakova, Maia R.; Gellermann, Werner

    2006-02-01

    Two major carotenoids species found in salmonids muscle tissues are astaxanthin and cantaxanthin. They are taken up from fish food and are responsible for the attractive red-orange color of salmon filet. Since carotenoids are powerful antioxidants and biomarkers of nutrient consumption, they are thought to indicate fish health and resistance to diseases in fish farm environments. Therefore, a rapid, accurate, quantitative optical technique for measuring carotenoid content in salmon tissues is of economic interest. We demonstrate the possibility of using fast, selective, quantitative detection of astaxanthin and cantaxanthin in salmon muscle tissues, employing resonance Raman spectroscopy. Analyzing strong Raman signals originating from the carbon-carbon double bond stretch vibrations of the carotenoid molecules under blue laser excitation, we are able to characterize quantitatively the concentrations of carotenoids in salmon muscle tissue. To validate the technique, we compared Raman data with absorption measurements of carotenoid extracts in acetone. A close correspondence was observed in absorption spectra for tissue extract in acetone and a pure astaxanthin solution. Raman results show a linear dependence between Raman and absorption data. The proposed technique holds promise as a method of rapid screening of carotenoid levels in fish muscle tissues and may be attractive for the fish farm industry to assess the dietary status of salmon, risk for infective diseases, and product quality control.

  12. UV/visible and surface-enhanced infrared studies of polyethylene/oriented gold nanoparticle composite films: The effects of gold particle size, shape, and orientation

    NASA Astrophysics Data System (ADS)

    Al-Rawashdeh, Nathir A. F.

    We have succeeded in preparing gold rods of high aspect ratio (>6) and diameter ca. ?32 nm, using anodically grown alumina films as host templates. To evaluate the sample quality, the plasmon resonance spectra of alumina/gold nanoparticle composite films were measured. In general, we found that the plasmon resonance maxima and intensity are dependent on the size, shape, and orientation of the gold nanoparticle. Furthermore, we have succeeded in orienting such nanoparticles in polyethylene matrices, and confirmed the net orientation via polarization studies in the UV/Visible/Near-IR region of the spectrum. In the polarization studies, we found that the extent of red-shift and damping of the plasmon resonance band are dependent on the size, shape, and orientation of the gold nanoparticle. The effects of gold particle size, shape, and orientation on the plasmon resonance spectra of polyethylene/oriented gold particle composite films have been compared to the predictions of Rayleigh scattering theory and effective medium theories (Maxwell-Garnett (MG) and Bruggeman (BRG)). From the comparison of the experimental plasmon resonance spectra with the calculated spectra using the above theories, we found that the best model for predicting the experimental plasmon resonance band shape and intensity is the BRG treatment. That finding has implications for what the sample is like. After we confirmed the net orientation of the nanoparticles in polyethylene matrices, we examined the infrared-transmittance spectra of 3-mercaptopropionic acid (MPA) and 11-mercaptoundecanoic acid (MUA) chemically bonded on such composite films via polarization studies. In general, we found that the IR-transmittance spectra of MPA and MUA show a polarization angle dependence. We discuss the effects of the gold particle shape, and orientation in the incident field on electromagnetic (EM) enhancements as seen in our oriented gold rod composite studies, in the context of the effective medium type theories for EM enhancements. From these studies, we found that the polarization infrared spectra of these IR-probe species show a polarization angle dependence that is consistent with the effective medium theories for EM spectral enhancements. Our conclusion is that a small enhancement in the intensity of the IR-probe is attributable to an EM enhancement. Large enhancements (ca. 500-fold) seen on previous studies are likely due to chemical effects (such as a charge transfer between the molecule and the metal particle).

  13. Multivariate reference technique for quantitative analysis of fiber-optic tissue Raman spectroscopy.

    PubMed

    Bergholt, Mads Sylvest; Duraipandian, Shiyamala; Zheng, Wei; Huang, Zhiwei

    2013-12-01

    We report a novel method making use of multivariate reference signals of fused silica and sapphire Raman signals generated from a ball-lens fiber-optic Raman probe for quantitative analysis of in vivo tissue Raman measurements in real time. Partial least-squares (PLS) regression modeling is applied to extract the characteristic internal reference Raman signals (e.g., shoulder of the prominent fused silica boson peak (~130 cm(-1)); distinct sapphire ball-lens peaks (380, 417, 646, and 751 cm(-1))) from the ball-lens fiber-optic Raman probe for quantitative analysis of fiber-optic Raman spectroscopy. To evaluate the analytical value of this novel multivariate reference technique, a rapid Raman spectroscopy system coupled with a ball-lens fiber-optic Raman probe is used for in vivo oral tissue Raman measurements (n = 25 subjects) under 785 nm laser excitation powers ranging from 5 to 65 mW. An accurate linear relationship (R(2) = 0.981) with a root-mean-square error of cross validation (RMSECV) of 2.5 mW can be obtained for predicting the laser excitation power changes based on a leave-one-subject-out cross-validation, which is superior to the normal univariate reference method (RMSE = 6.2 mW). A root-mean-square error of prediction (RMSEP) of 2.4 mW (R(2) = 0.985) can also be achieved for laser power prediction in real time when we applied the multivariate method independently on the five new subjects (n = 166 spectra). We further apply the multivariate reference technique for quantitative analysis of gelatin tissue phantoms that gives rise to an RMSEP of ~2.0% (R(2) = 0.998) independent of laser excitation power variations. This work demonstrates that multivariate reference technique can be advantageously used to monitor and correct the variations of laser excitation power and fiber coupling efficiency in situ for standardizing the tissue Raman intensity to realize quantitative analysis of tissue Raman measurements in vivo, which is particularly appealing in challenging Raman endoscopic applications. PMID:24160634

  14. Detection and quantitative analysis of ferrocyanide and ferricyanide: FY 93 Florida State University Raman spectroscopy report

    SciTech Connect

    Mann, C.K.; Vickers, T.J. [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry

    1994-10-11

    This report provides a summary of work to develop and investigate the feasibility of using Raman spectroscopy with tank waste materials. It contains Raman spectra from organics, such as ethylenediaminetetraacetic acid (EDTA), hydroxyethylenediaminetetraacteic acid (HEDTA), imino diacetic acid (IDA), kerosene, tributyl phosphate (TBP), acetone and butanol, anticipated to be present in tank wastes and spectra from T-107 real and BY-104 simulant materials. The results of investigating Raman for determining moisture content in tank materials are also presented. A description of software algorithms developed to process Raman spectra from a dispersive grating spectrometer system and an in initial design for a data base to support qualitative and quantitative application of remote Raman sensing with tank wastes.

  15. Quantitative analysis of sesquiterpene lactones in extract of Arnica montana L. by 1H NMR spectroscopy.

    PubMed

    Staneva, Jordanka; Denkova, Pavletta; Todorova, Milka; Evstatieva, Ljuba

    2011-01-01

    (1)H NMR spectroscopy was used as a method for quantitative analysis of sesquiterpene lactones present in a crude lactone fraction isolated from Arnica montana. Eight main components - tigloyl-, methacryloyl-, isobutyryl- and 2-methylbutyryl-esters of helenalin (H) and 11?,13-dihydrohelenalin (DH) were identified in the studied sample. The method allows the determination of the total amount of sesquiterpene lactones and the quantity of both type helenalin and 11?,13-dihydrohelenalin esters separately. Furthermore, 6-O-tigloylhelenalin (HT, 1), 6-O-methacryloylhelenalin (HM, 2), 6-O-tigloyl-11?,13-dihydrohelenalin (DHT, 5), and 6-O-methacryloyl-11?,13-dihydrohelenalin (DHM, 6) were quantified as individual components. PMID:20837387

  16. Matrix Effects in Quantitative Assessment of Pharmaceutical Tablets Using Transmission Raman and Near-Infrared (NIR) Spectroscopy.

    PubMed

    Sparén, Anders; Hartman, Madeleine; Fransson, Magnus; Johansson, Jonas; Svensson, Olof

    2015-05-01

    Raman spectroscopy can be an alternative to near-infrared spectroscopy (NIR) for nondestructive quantitative analysis of solid pharmaceutical formulations. Compared with NIR spectra, Raman spectra have much better selectivity, but subsampling was always an issue for quantitative assessment. Raman spectroscopy in transmission mode has reduced this issue, since a large volume of the sample is measured in transmission mode. The sample matrix, such as particle size of the drug substance in a tablet, may affect the Raman signal. In this work, matrix effects in transmission NIR and Raman spectroscopy were systematically investigated for a solid pharmaceutical formulation. Tablets were manufactured according to an experimental design, varying the factors particle size of the drug substance (DS), particle size of the filler, compression force, and content of drug substance. All factors were varied at two levels plus a center point, except the drug substance content, which was varied at five levels. Six tablets from each experimental point were measured with transmission NIR and Raman spectroscopy, and their concentration of DS was determined for a third of those tablets. Principal component analysis of NIR and Raman spectra showed that the drug substance content and particle size, the particle size of the filler, and the compression force affected both NIR and Raman spectra. For quantitative assessment, orthogonal partial least squares regression was applied. All factors varied in the experimental design influenced the prediction of the DS content to some extent, both for NIR and Raman spectroscopy, the particle size of the filler having the largest effect. When all matrix variations were included in the multivariate calibrations, however, good predictions of all types of tablets were obtained, both for NIR and Raman spectroscopy. The prediction error using transmission Raman spectroscopy was about 30% lower than that obtained with transmission NIR spectroscopy. PMID:25811389

  17. Characterization of geometrical factors for quantitative angle-resolved photoelectron spectroscopy

    SciTech Connect

    Martinez, Eugenie; Herrera-Gomez, Alberto; Allain, Mickael; Renault, Olivier; Faure, Alain; Chabli, Amal; Bertin, Francois [CEA, LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France); CINVESTAV-Queretaro, Libramiento Norponiente 2000, Real de Juriquilla, Queretaro, 76000 (Mexico); CEA, LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France)

    2012-07-15

    For conventional angle-resolved x-ray photoelectron spectroscopy (ARXPS), the area under the core-level peaks depends mainly on the in-depth distribution of chemical species at the top surface of a specimen. But the x-ray photoelectron spectroscopy (XPS) intensity is also affected by tool-related geometrical factors such as the shape of the x-ray beam, the spectrometer analysis volume, and the manipulator rotation axis. Data analysis is therefore typically based on normalization with respect to the signal from the substrate. Here, we present an original method to perform quantitative ARXPS without normalization, involving evaluation of these geometrical factors. The method is illustrated for a multiprobe XPS system using a methodology based on a specific software (XPSGeometry{sup Registered-Sign }), but is a general process that can be adapted to all types of XPS equipment, even those not specifically designed for ARXPS. In that case, this method enables bringing the sample as close as possible to the manipulator axis of rotation in order to perform automatic acquisitions.

  18. [Quantitative measurement of induced skin reddening using optical reflection spectroscopy--methodology and clinical application].

    PubMed

    Smesny, S; Riemann, S; Riehemann, S; Bellemann, M E; Sauer, H

    2001-10-01

    Optical reflection spectroscopy is a simple and quick method for the quantification of colour intensity, and is thus suitable for the determination of changes in skin reddening (erythema) due to local vasodilatation. To quantify the time course of this erythema, the oxyhaemoglobin absorption double peak with maxima at 542 and 577 nm is an appropriate parameter. A compact handheld optical spectrometer makes the technique applicable to clinical use, an example being the niacin patch test described herein. This noninvasive test provides information about the cell membrane metabolism via the skin flush induced by niacin (vitamin B3) and mediated by prostaglandin. The aim of this study was to adapt optical reflection spectroscopy to the requirements of the clinical niacin patch test. To that end, we investigated 60 healthy volunteers. Analysis of the spectroscopic data with regard to physiological covariables of niacin sensitivity revealed faster and more intense erythema in females--a gender effect that to our knowledge has not previously been reported. In the light of these results, the findings of other researchers based on semi-quantitative test methods should be reassessed, with consideration given to the gender effect. PMID:11721583

  19. Quantitative classification of cryptosporidium oocysts and giardia cysts in water using UV/vis spectroscopy

    NASA Astrophysics Data System (ADS)

    Bacon, Christina P.; Rose, J. B.; Patten, K.; Garcia-Rubio, Luis H.

    1995-05-01

    Cryptosporidium and Giardia are enteric protozoa which cause waterborne diseases. To date, the detection of these organisms in water has relied upon microscopic immunofluorescent assay technology which uses antibodies directed against the cyst and oocyst forms of the protozoa. In this paper, the uv/vis extinction spectra of aqueous dispersions of Cryptosporidium and Giardia have been studied to investigate the potential use of light scattering-spectral deconvolution techniques as a rapid method for the identification and quantification of protozoa in water. Examination of purified samples of Cryptosporidium and Giardia suggests that spectral features apparent in the short wavelength region of the uv/vis spectra contain information that may be species specific for each protozoa. The spectral characteristics, as well as the particle size analysis, determined from the same spectra, allow for the quantitative classification, identification, and possibly, the assessment of the viability of the protozoa. To further increase the sensitivity of this technique, specific antibodies direction against these organisms, labelled with FITC and rhodamine are being used. It is demonstrated that uv/vis spectroscopy provides an alternative method for the characterization of Giardia and Cryptosporidium. The simplicity and reproducibility of uv/vis spectroscopy measurements makes this technique ideally suited for the development of on-line instrumentation for the rapid detection of microorganisms in water supplies.

  20. Quantitative characterization of the colloidal stability of metallic nanoparticles using UV-vis absorbance spectroscopy.

    PubMed

    Ray, Tyler R; Lettiere, Bethany; de Rutte, Joseph; Pennathur, Sumita

    2015-03-31

    Plasmonic nanoparticles are used in a wide variety of applications over a broad array of fields including medicine, energy, and environmental chemistry. The continued successful development of this material class requires the accurate characterization of nanoparticle stability for a variety of solution-based conditions. Although many characterization methods exists, there is an absence of a unified, quantitative means for assessing the colloidal stability of plasmonic nanoparticles. We present the particle instability parameter (PIP) as a robust, quantitative, and generalizable characterization technique based on UV-vis absorbance spectroscopy to characterize colloidal instability. We validate PIP performance with both traditional and alternative characterization methods by measuring gold nanorod instability in response to different salt (NaCl) concentrations. We further measure gold nanorod stability as a function of solution pH, salt, and buffer (type and concentration), nanoparticle concentration, and concentration of free surfactant. Finally, these results are contextualized within the literature on gold nanorod stability to establish a standardized methodology for colloidal instability assessment. PMID:25730093

  1. A new Schiff base compound N,N'-(2,2-dimetylpropane)-bis(dihydroxylacetophenone): synthesis, experimental and theoretical studies on its crystal structure, FTIR, UV-visible, 1H NMR and 13C NMR spectra.

    PubMed

    Saheb, Vahid; Sheikhshoaie, Iran

    2011-10-15

    The Schiff base compound, N,N'-(2,2-dimetylpropane)-bis(dihydroxylacetophenone) (NDHA) is synthesized through the condensation of 2-hydroxylacetophenone and 2,2-dimethyl 1,3-amino propane in methanol at ambient temperature. The yellow crystalline precipitate is used for X-ray single-crystal determination and measuring Fourier transform infrared (FTIR), UV-visible, (1)H NMR and (13)C NMR spectra. Electronic structure calculations at the B3LYP, PBEPBE and PW91PW91 levels of theory are performed to optimize the molecular geometry and to calculate the FTIR, (1)H NMR and (13)C NMR spectra of the compound. Time-dependent density functional theory (TDDFT) method is used to calculate the UV-visible spectrum of NDHA. Vibrational frequencies are determined experimentally and compared with those obtained theoretically. Vibrational assignments and analysis of the fundamental modes of the compound are also performed. All theoretical methods can well reproduce the structure of the compound. The (1)H NMR and (13)C NMR chemical shifts calculated by all DFT methods are consistent with the experimental data. However, the NMR shielding tensors computed at the B3LYP/6-31+G(d,p) level of theory are in better agreement with experimental (1)H NMR and (13)C NMR spectra. The electronic absorption spectrum calculated at the B3LYP/6-31+G(d,p) level by using TD-DFT method is in accordance with the observed UV-visible spectrum of NDHA. In addition, some quantum descriptors of the molecule are calculated and conformational analysis is performed and the results were compared with the crystallographic data. PMID:21763188

  2. Quantitative analysis of cefalexin based on artificial neural networks combined with modified genetic algorithm using short near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Huan, Yanfu; Feng, Guodong; Wang, Bin; Ren, Yulin; Fei, Qiang

    2013-05-01

    In this paper, a novel chemometric method was developed for rapid, accurate, and quantitative analysis of cefalexin in samples. The experiments were carried out by using the short near-infrared spectroscopy coupled with artificial neural networks. In order to enhancing the predictive ability of artificial neural networks model, a modified genetic algorithm was used to select fixed number of wavelength.

  3. ATR-FTIR spectroscopy and quantitative multivariate analysis of paints and coating materials

    NASA Astrophysics Data System (ADS)

    Hayes, Philippa Alice; Vahur, Signe; Leito, Ivo

    2014-12-01

    The applicability of ATR-FTIR spectroscopy with partial least squares (PLS) data analysis was evaluated for quantifying the components of mixtures of paint binding media and pigments, and alkyd resins. PLS methods were created using a number of standard mixtures. Validation and measurement uncertainty estimation was carried out. Binary, ternary and quaternary mixtures of several common binding media and pigments were quantified, with standard measurement uncertainties in most cases below 3 g/100 g. Classes of components - aromatic anhydrides and alcohols - used in alkyd resin synthesis were also successfully quantified, with standard uncertainties in the range of 2-3 g/100 g. This is a more demanding application because in alkyd resins aromatic anhydrides and alcohols have reacted to form a polyester, and are not present in their original forms. Once a PLS method has been calibrated, analysis time and cost are significantly reduced from typical quantitative methods such as GC/MS. This is beneficial in the case of routine analysis where the components are known.

  4. Broadband reflectance spectroscopy for establishing a quantitative metric of vascular leak using the Miles assay

    NASA Astrophysics Data System (ADS)

    McMurdy, John; Reichner, Jonathan; Mathews, Zara; Markey, Mary; Intwala, Sunny; Crawford, Gregory

    2009-09-01

    Monitoring the physiological effects of biological mediators on vascular permeability is important for identifying potential targets for antivascular leak therapy. This therapy is relevant to treatments for pulmonary edema and other disorders. Current methods of quantifying vascular leak are in vitro and do not allow repeated measurement of the same animal. Using an in vivo diffuse reflectance optical method allows pharmacokinetic analysis of candidate antileak molecules. Here, vascular leak is assessed in mice and rats by using the Miles assay and introducing irritation both topically using mustard oil and intradermally using vascular endothelial growth factor (VEGF). The severity of the leak is assessed using broadband diffuse reflectance spectroscopy with a fiber reflectance probe. Postprocessing techniques are applied to extract an artificial quantitative metric of leak from reflectance spectra at vascular leak sites on the skin of the animal. This leak metric is calculated with respect to elapsed time from irritation in both mustard oil and VEGF treatments on mice and VEGF treatments on rats, showing a repeatable increase in leak metric with leak severity. Furthermore, effects of pressure on the leak metric are observed to have minimal effect on the reflectance spectra, while spatial positioning showed spatially nonuniform leak sites.

  5. Quantitative estimation of concentrations of dissolved rare earth elements using reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Dai, Jingjing; Wang, Denghong; Wang, Runsheng; Chen, Zhenghui

    2013-01-01

    Characteristic spectral parameters such as the wavelength and depth of absorption bands are widely used to quantitatively estimate the composition of samples from hyperspectral reflectance data in soil science, mineralogy as well as vegetation study. However, little research has been conducted on the spectral characteristic of rare earth elements (REE) and their relationship with chemical composition of aqueous solutions. Reflectance spectra of ore leachate solutions and contaminated stream water from a few REE mines in the Jiangxi Province, China, are studied for the first time in this work. The results demonstrate that the six diagnostic absorption features of the rare earths are recognized in visible and near-infrared wavelengths at 574, 790, 736, 520, 861, and 443 nm. The intensity of each of these six absorption bands is linearly correlated with the abundance of total REE, with the r2 value >0.95 and the detection limit at ?75,000 ?g/L. It is suggested that reflectance spectroscopy provides an ideal routine analytical tool for characterizing leachate samples. The outcome of this study also has implications for monitoring the environmental effect of REE mining, in particular in stream water systems by hyperspectral remote sensing.

  6. ATR-FTIR spectroscopy and quantitative multivariate analysis of paints and coating materials.

    PubMed

    Hayes, Philippa Alice; Vahur, Signe; Leito, Ivo

    2014-12-10

    The applicability of ATR-FTIR spectroscopy with partial least squares (PLS) data analysis was evaluated for quantifying the components of mixtures of paint binding media and pigments, and alkyd resins. PLS methods were created using a number of standard mixtures. Validation and measurement uncertainty estimation was carried out. Binary, ternary and quaternary mixtures of several common binding media and pigments were quantified, with standard measurement uncertainties in most cases below 3g/100g. Classes of components - aromatic anhydrides and alcohols - used in alkyd resin synthesis were also successfully quantified, with standard uncertainties in the range of 2-3g/100g. This is a more demanding application because in alkyd resins aromatic anhydrides and alcohols have reacted to form a polyester, and are not present in their original forms. Once a PLS method has been calibrated, analysis time and cost are significantly reduced from typical quantitative methods such as GC/MS. This is beneficial in the case of routine analysis where the components are known. PMID:24945861

  7. Quantitative analysis and detection of adulteration in pork using near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Fan, Yuxia; Cheng, Fang; Xie, Lijuan

    2010-04-01

    Authenticity is an important food quality criterion. Rapid methods for confirming authenticity or detecting adulteration are increasingly demanded by food processors and consumers. Near infrared (NIR) spectroscopy has been used to detect economic adulteration in pork . Pork samples were adulterated with liver and chicken in 10% increments. Prediction and quantitative analysis were done using raw data and pretreatment spectra. The optimal prediction result was achieved by partial least aquares(PLS) regression with standard normal variate(SNV) pretreatment for pork adulterated with liver samples, and the correlation coefficient(R value), the root mean square error of calibration(RMSEC) and the root mean square error of prediction (RMSEP) were 0.97706, 0.0673 and 0.0732, respectively. The best model for pork meat adulterated with chicken samples was obtained by PLS with the raw spectra, and the correlation coefficient(R value), RMSEP and RMSEC were 0.98614, 0.0525, and 0.122, respectively. The result shows that NIR technology can be successfully used to detect adulteration in pork meat adulterated with liver and chicken.

  8. Fast quantitative determination of platinum in liquid samples by laser-induced breakdown spectroscopy.

    PubMed

    Barreda, Flory-Anne; Trichard, Florian; Barbier, Sophie; Gilon, Nicole; Saint-Jalmes, Laurent

    2012-07-01

    The potential of laser-induced breakdown spectroscopy (LIBS) for the rapid determination of platinum in liquid silicone oils has been evaluated in the framework of on-line process control. A comparison of LIBS sensitivity between three setups designed for liquid analysis (static, liquid jet and flowing liquid) was performed using a 266 nm Nd/YAG laser irradiation. Best results were obtained using the flowing liquid setup and a similar limit of detection was obtained using the liquid jet. The effect of different buffer gases (Ar, He, N(2), etc.) on the signal sensitivity was studied in liquid jet analysis and best values were obtained with a nitrogen sheath gas. Detection limits were in the 100 mg/kg range for both setups. Quantitative determination of platinum in real liquid samples was also investigated using both liquid jet and flowing liquid setups. Calibration curves were plotted for Pt with the liquid jet and the flowing liquid setups under optimised temporal acquisition parameters (delay time and gate width). A normalisation using a silicon line was applied and recovery ranged from 3 to 15% for Pt in catalyst samples with both setups showing that LIBS is a sensitive and accurate method for on-line applications. PMID:22547353

  9. Neoadjuvant chemotherapy in breast cancer: early response prediction with quantitative MR imaging and spectroscopy

    PubMed Central

    Manton, D J; Chaturvedi, A; Hubbard, A; Lind, M J; Lowry, M; Maraveyas, A; Pickles, M D; Tozer, D J; Turnbull, L W

    2006-01-01

    A prospective study was undertaken in women undergoing neoadjuvant chemotherapy for locally advanced breast cancer in order to determine the ability of quantitative magnetic resonance imaging (MRI) and proton spectroscopy (MRS) to predict ultimate tumour response (percentage decrease in volume) or to detect early response. Magnetic resonance imaging and MRS were carried out before treatment and after the second of six treatment cycles. Pharmacokinetic parameters were derived from T1-weighted dynamic contrast-enhanced MRI, water apparent diffusion coefficient (ADC) was measured, and tissue water?:?fat peak area ratios and water T2 were measured using unsuppressed one-dimensional proton spectroscopic imaging (30 and 135?ms echo times). Pharmacokinetic parameters and ADC did not detect early response; however, early changes in water?:?fat ratios and water T2 (after cycle two) demonstrated substantial prognostic efficacy. Larger decreases in water T2 accurately predicted final volume response in 69% of cases (11/16) while maintaining 100% specificity and positive predictive value. Small/absent decreases in water?:?fat ratios accurately predicted final volume non-response in 50% of cases (3/6) while maintaining 100% sensitivity and negative predictive value. This level of accuracy might permit clinical application where early, accurate prediction of non-response would permit an early change to second-line treatment, thus sparing patients unnecessary toxicity, psychological morbidity and delay of initiation of effective treatment. PMID:16465174

  10. Improved calculation of the backscattering factor for quantitative analysis by Auger electron spectroscopy

    SciTech Connect

    Ding, Z. J.; Tan, W. S.; Li, Y. G. [Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, 230026 Anhui (China) and Department of Physics, University of Science and Technology of China, Hefei, 230026 Anhui (China)

    2006-04-15

    Based on a Monte Carlo simulation method, an improved calculation of the backscattering factor in quantitative analysis by Auger electron spectroscopy has been performed by integrating several aspects of recent progresses in the related fields. The calculation used a general definition of backscattering factor, more accurate ionization cross section, up-to-date Monte Carlo model of electron inelastic scattering, and a large number of electron trajectories to ensure less statistical error. The results reveal several noticeable properties of backscattering factor, i.e., its slow variation with primary energy at higher overvoltage ratios, and dependence on the geometrical configuration of a detector. However, only for large emission angles of Auger signals a considerable angular dependence of backscattering factor is found. Specifically a calculation is carried out for detection in the solid angles of a cylindrical mirror analyzer. This backscattering factor can be less than unity for very low primary energies closing to ionization energy and/or for large incident angles. The physical cause has been detailed and analyzed.

  11. Quantitative determination of sulfur content in concrete with laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Weritz, F.; Ryahi, S.; Schaurich, D.; Taffe, A.; Wilsch, G.

    2005-08-01

    Laser-induced breakdown spectroscopy has been employed for the investigation of the sulfur content of concrete. Sulfur compounds are a natural but minor component in building materials. The ingress of sulfates or sulfuric acid constitutes a major risk of chemical aggression for concrete. There is a need for a fast method, which can be used on-site and is able to investigate a wide range of different measuring points, so that damages can be characterized. For quantitative determination the sulfur spectral line at 921.3 nm is used. The optimum ambient atmosphere has been determined by comparison of measurements accomplished under air, argon and helium atmosphere. Reference samples have been produced and calibration curves have been determined, the results of LIBS measurements are compared with results from chemical analysis. Defining a limit for the intensity ratio of a calcium and a oxygen spectral line can reduce the influence of the heterogeneity of the material, so that only spectra with a high amount of cementitious material are evaluated. Depth profiles and spatial resolved sulfur distributions are presented measured on concrete cores originating from a highly sulfate contaminated clarifier.

  12. Quantitative estimation of carbonation and chloride penetration in reinforced concrete by laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Eto, Shuzo; Matsuo, Toyofumi; Matsumura, Takuro; Fujii, Takashi; Tanaka, Masayoshi Y.

    2014-11-01

    The penetration profile of chlorine in a reinforced concrete (RC) specimen was determined by laser-induced breakdown spectroscopy (LIBS). The concrete core was prepared from RC beams with cracking damage induced by bending load and salt water spraying. LIBS was performed using a specimen that was obtained by splitting the concrete core, and the line scan of laser pulses gave the two-dimensional emission intensity profiles of 100 × 80 mm2 within one hour. The two-dimensional profile of the emission intensity suggests that the presence of the crack had less effect on the emission intensity when the measurement interval was larger than the crack width. The chlorine emission spectrum was measured without using the buffer gas, which is usually used for chlorine measurement, by collinear double-pulse LIBS. The apparent diffusion coefficient, which is one of the most important parameters for chloride penetration in concrete, was estimated using the depth profile of chlorine emission intensity and Fick's law. The carbonation depth was estimated on the basis of the relationship between carbon and calcium emission intensities. When the carbon emission intensity was statistically higher than the calcium emission intensity at the measurement point, we determined that the point was carbonated. The estimation results were consistent with the spraying test results using phenolphthalein solution. These results suggest that the quantitative estimation by LIBS of carbonation depth and chloride penetration can be performed simultaneously.

  13. Final Report: Investigation of Polarization Spectroscopy and Degenerate Four-Wave Mixing for Quantitative Concentration Measurements

    SciTech Connect

    Robert P. Lucht

    2005-03-09

    Laser-induced polarization spectroscopy (LIPS), degenerate four-wave mixing (DFWM), and electronic-resonance-enhanced (ERE) coherent anti-Stokes Raman scattering (CARS) are techniques that shows great promise for sensitive measurements of transient gas-phase species, and diagnostic applications of these techniques are being pursued actively at laboratories throughout the world. However, significant questions remain regarding strategies for quantitative concentration measurements using these techniques. The primary objective of this research program is to develop and test strategies for quantitative concentration measurements in flames and plasmas using these nonlinear optical techniques. Theoretically, we are investigating the physics of these processes by direct numerical integration (DNI) of the time-dependent density matrix equations that describe the wave-mixing interaction. Significantly fewer restrictive assumptions are required when the density matrix equations are solved using this DNI approach compared with the assumptions required to obtain analytical solutions. For example, for LIPS calculations, the Zeeman state structure and hyperfine structure of the resonance and effects such as Doppler broadening can be included. There is no restriction on the intensity of the pump and probe beams in these nonperturbative calculations, and both the pump and probe beam intensities can be high enough to saturate the resonance. As computer processing speeds have increased, we have incorporated more complicated physical models into our DNI codes. During the last project period we developed numerical methods for nonperturbative calculations of the two-photon absorption process. Experimentally, diagnostic techniques are developed and demonstrated in gas cells and/or well-characterized flames for ease of comparison with model results. The techniques of two-photon, two-color H-atom LIPS and three-laser ERE CARS for NO and C{sub 2}H{sub 2} were demonstrated during the project period, and nonperturbative numerical models of both of these techniques were developed. In addition, we developed new single-mode, injection-seeded optical parametric laser sources (OPLSs) that will be used to replace multi-mode commercial dye lasers in our experimental measurements. The use of single-mode laser radiation in our experiments will increase significantly the rigor with which theory and experiment are compared.

  14. Cancer therapy prognosis using quantitative ultrasound spectroscopy and a kernel-based metric

    NASA Astrophysics Data System (ADS)

    Gangeh, Mehrdad J.; Hashim, Amr; Giles, Anoja; Czarnota, Gregory J.

    2014-03-01

    In this study, a kernel-based metric based on the Hilbert-Schmidt independence criterion (HSIC) is proposed in a computer-aided-prognosis system to monitor cancer therapy effects. In order to induce tumour cell death, sarcoma xenograft tumour-bearing mice were injected with microbubbles followed by ultrasound and X-ray radiation therapy successively as a new anti-vascular treatment. High frequency (central frequency 30 MHz) ultrasound imaging was performed before and at different times after treatment and using spectroscopy, quantitative ultrasound (QUS) parametric maps were derived from the radiofrequency (RF) signals. The intensity histogram of midband fit parametric maps was computed to represent the pre- and post-treatment images. Subsequently, the HSIC-based metric between preand post-treatment samples were computed for each animal as a measure of distance between the two distributions. The HSIC-based metrics computes the distance between two distributions in a reproducing kernel Hilbert space (RKHS), meaning that by using a kernel, the input vectors are non-linearly mapped into a different, possibly high dimensional feature space. Computing the population means in this new space, enhanced group separability (compared to, e.g., Euclidean distance in the original feature space) is ideally obtained. The pre- and post-treatment parametric maps for each animal were thus represented by a dissimilarity measure, in which a high value of this metric indicated more treatment effect on the animal. It was shown in this research that this metric has a high correlation with cell death and if it was used in supervised learning, a high accuracy classification was obtained using a k-nearest-neighbor (k-NN) classifier.

  15. Quantitative treatment of coarsely binned low-resolution recordings in molecular absorption spectroscopy.

    PubMed

    Spietz, Peter; Martín, Juan Carlos Gómez; Burrows, John P

    2006-06-01

    Optical multichannel detectors like photodiode arrays or CCD cameras combined with grating spectrometers are commonly used as detection systems in quantitative absorption spectroscopy. As a trade-off to broad spectral coverage, banded spectral features are sometimes recorded with insufficient spectral resolution and/or insufficiently fine detector binning. This renders the true physical spectrum of recorded intensities changed by instrumental and spectrum specific artefacts thus impeding comparability between results from different set-ups. In this work, it is demonstrated that in the case of a "well-behaved"--i.e. free of ro-vibronic structure--absorption band like the iodine monoxide IO(4<--0) transition, these effects can easily change the apparent peak absorption by up to 50%. Also deviations from the strict linearity (Beer-Lambert's law) between absorber concentration and apparent, i.e. pixelwise optical density occur. This can be critical in studies of chemical kinetics. It is shown that the observed non-linearity can cause errors of up to 50% in the determination of a second order rate coefficient for the IO self reaction. To overcome the problem, a consistent and rigorous integral approach for the treatment of intensity recordings is developed. Linearity between optical density and absorber concentration thereby is re-established. The method is validated using artificial test data as well as experimental data of the IO(4<--0) absorption transition, obtained in the context of I2/O3 photochemistry studies. The agreement is accurate to within +/-2% (test data) and +/-3% (experimental data) supporting the validity of the approach. Possible consequences for other spectroscopic work are indicated. PMID:16387540

  16. Quantitative treatment of coarsely binned low-resolution recordings in molecular absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Spietz, Peter; Martín, Juan Carlos Gómez; Burrows, John P.

    2006-06-01

    Optical multichannel detectors like photodiode arrays or CCD cameras combined with grating spectrometers are commonly used as detection systems in quantitative absorption spectroscopy. As a trade-off to broad spectral coverage, banded spectral features are sometimes recorded with insufficient spectral resolution and/or insufficiently fine detector binning. This renders the true physical spectrum of recorded intensities changed by instrumental and spectrum specific artefacts thus impeding comparability between results from different set-ups. In this work, it is demonstrated that in the case of a "well-behaved" - i.e. free of ro-vibronic structure - absorption band like the iodine monoxide IO(4 ? 0) transition, these effects can easily change the apparent peak absorption by up to 50%. Also deviations from the strict linearity (Beer-Lambert's law) between absorber concentration and apparent, i.e. pixelwise optical density occur. This can be critical in studies of chemical kinetics. It is shown that the observed non-linearity can cause errors of up to 50% in the determination of a second order rate coefficient for the IO self reaction. To overcome the problem, a consistent and rigorous integral approach for the treatment of intensity recordings is developed. Linearity between optical density and absorber concentration thereby is re-established. The method is validated using artificial test data as well as experimental data of the IO(4 ? 0) absorption transition, obtained in the context of I 2/O 3 photochemistry studies. The agreement is accurate to within ±2% (test data) and ±3% (experimental data) supporting the validity of the approach. Possible consequences for other spectroscopic work are indicated.

  17. Quantitative Cardiac 31P Spectroscopy at 3T Using Adiabatic Pulses

    PubMed Central

    El-Sharkawy, AbdEl-Monem; Schär, Michael; Ouwerkerk, Ronald; Weiss, Robert G.; Bottomley, Paul A.

    2011-01-01

    Cardiac phosphorus magnetic resonance spectroscopy (MRS) with surface coils promises better quantification at 3T due to improved signal-to-noise ratios and spectral resolution compared to 1.5T. However, Bloch equation and field analyses at 3T show that for efficient quantitative MRS protocols employing small-angle adiabatic (BIR4/BIRP) pulses the excitation-field is limited by RF power requirements and power deposition. When BIR4/BIRP pulse duration is increased to reduce power levels, T2-decay can introduce flip-angle dependent errors in the steady-state magnetization, causing errors in saturation corrections for metabolite quantification and in T1s measured by varying the flip-angle. A new dual-repetition-time (2TR) T1 method using frequency-sign-cycled adiabatic-half-passage pulses is introduced to alleviate power requirements, and avoid the problem related to T2 relaxation during the RF pulse. The 2TR method is validated against inversion-recovery in phantoms using a practical transmit/receive coil set designed for phosphorus MRS of the heart at depths of 9-10 cm with 4kW of pulse power. The T1s of phosphocreatine (PCr) and adenosine triphosphate (?-ATP) in the calf-muscle (n=9) at 3T are 6.8±0.3s and 5.4±0.6s respectively. For heart (n=10) the values are 5.8±0.5s (PCr) and 3.1±0.6s (?-ATP). The 2TR protocol measurements agreed with those obtained by conventional methods to within 10%. PMID:19195018

  18. Structural changes of yellow Cameleon domains observed by quantitative FRET analysis and polarized fluorescence correlation spectroscopy.

    PubMed

    Borst, J W; Laptenok, S P; Westphal, A H; Kühnemuth, R; Hornen, H; Visser, N V; Kalinin, S; Aker, J; van Hoek, A; Seidel, C A M; Visser, A J W G

    2008-12-01

    Förster resonance energy transfer (FRET) is a widely used method for monitoring interactions between or within biological macromolecules conjugated with suitable donor-acceptor pairs. Donor fluorescence lifetimes in absence and presence of acceptor molecules are often measured for the observation of FRET. However, these lifetimes may originate from interacting and noninteracting molecules, which hampers quantitative interpretation of FRET data. We describe a methodology for the detection of FRET that monitors the rise time of acceptor fluorescence on donor excitation thereby detecting only those molecules undergoing FRET. The large advantage of this method, as compared to donor fluorescence quenching method used more commonly, is that the transfer rate of FRET can be determined accurately even in cases where the FRET efficiencies approach 100% yielding highly quenched donor fluorescence. Subsequently, the relative orientation between donor and acceptor chromophores is obtained from time-dependent fluorescence anisotropy measurements carried out under identical conditions of donor excitation and acceptor detection. The FRET based calcium sensor Yellow Cameleon 3.60 (YC3.60) was used because it changes its conformation on calcium binding, thereby increasing the FRET efficiency. After mapping distances and orientation angles between the FRET moieties in YC3.60, cartoon models of this FRET sensor with and without calcium could be created. Independent support for these representations came from experiments where the hydrodynamic properties of YC3.60 under ensemble and single-molecule conditions on selective excitation of the acceptor were determined. From rotational diffusion times as found by fluorescence correlation spectroscopy and consistently by fluorescence anisotropy decay analysis it could be concluded that the open structure (without calcium) is flexible as opposed to the rather rigid closed conformation. The combination of two independent methods gives consistent results and presents a rapid and specific methodology to analyze structural and dynamical changes in a protein on ligand binding. PMID:18790855

  19. An efficient triazole-based fluorescent "turn-on" receptor for naked-eye recognition of F- and AcO-: UV-visible, fluorescence and 1H NMR studies.

    PubMed

    Kumar, M Saravana; Kumar, S L Ashok; Sreekanth, A

    2013-08-01

    An efficient colorimetric receptor was developed by a simple convenient method which exhibited naked-eye sensitivity for fluoride and acetate in a biologically competing solvent like DMSO. The receptor developed, portrayed a substantial change in the UV-visible absorption characteristics upon addition of fluoride and acetate anions over other anions. The binding constants showed that the binding ability of receptor towards F(-) anion was slightly higher than that of the AcO(-) anion. Job's plots indicated the formation of a (1:1) complex (receptor:anion) of receptor with fluoride and acetate anions respectively. A "turn on" fluorescence response with a red shift was observed upon fluorescence titration. (1)H NMR titration experiments revealed the mechanism to be driven by the hydrogen bonding interaction of amide NH and phenol OH of the receptor molecule which was followed by deprotonation in the receptor by the F(-) and AcO(-) anions. PMID:23706220

  20. Multivariate processing strategies for enhancing qualitative and quantitative analysis based on infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Wan, Boyong

    2007-12-01

    Airborne passive Fourier transform infrared spectrometry is gaining increased attention in environmental applications because of its great flexibility. Usually, pattern recognition techniques are used for automatic analysis of large amount of collected data. However, challenging problems are the constantly changing background and high calibration cost. As aircraft is flying, background is always changing. Also, considering the great variety of backgrounds and high expense of data collection from aircraft, cost of collecting representative training data is formidable. Instead of using airborne data, data generated from simulation strategies can be used for training purposes. Training data collected under controlled conditions on the ground or synthesized from real backgrounds can be both options. With both strategies, classifiers may be developed with much lower cost. For both strategies, signal processing techniques need to be used to extract analyte features. In this dissertation, signal processing methods are applied either in interferogram or spectral domain for features extraction. Then, pattern recognition methods are applied to develop binary classifiers for automated detection of air-collected methanol and ethanol vapors. The results demonstrate, with optimized signal processing methods and training set composition, classifiers trained from ground-collected or synthetic data can give good classification on real air-collected data. Near-infrared (NIR) spectrometry is emerging as a promising tool for noninvasive blood glucose detection. In combination with multivariate calibration techniques, NIR spectroscopy can give quick quantitative determinations of many species with minimal sample preparation. However, one main problem with NIR calibrations is degradation of calibration model over time. The varying background information will worsen the prediction precision and complicate the multivariate models. To mitigate the needs for frequent recalibration and improve robustness of calibration models, signal processing methods can be used to decrease the influence of such non-constant background variation. In this dissertation, signal processing methods are also applied to NIR single-beam spectra collected during short-term and long-term studies. The prediction performance of the calibration models demonstrates, with suppression of non-constant background information by optimal wavelet processing procedures, robustness of calibration models with time can be significantly improved.

  1. Quantitative structural and textural assessment of laminar pyrocarbons through Raman spectroscopy, electron diffraction

    E-print Network

    Boyer, Edmond

    spectroscopy; Electron energy- loss spectroscopy 1. Introduction Rough laminar pyrocarbon (RL) has been-cross when observed by polarized optical microscopy. The development of new densification methods of felts (FWHMD) is very sensitive to low energy structural defects (e.g., disorientations of the graphene layers

  2. Substrate and instrumental effects in quantitative Auger electron spectroscopy: the system lead on gold

    Microsoft Academic Search

    M. G. Barthes; G. E. Rhead

    1980-01-01

    New and previously published AES data on monolayer and surface compound formation during the first stages of deposition of lead on gold are critically examined. The system serves as a 'test case' for quantitative AES. Comparison of results obtained with different single crystals substrates and with different spectrometers show quantitative differences of up to a factor of two. It is

  3. Quantitative assessment of the ion-beam irradiation induced direct damage of nucleic acid bases through FTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Huang, Qing; Su, Xi; Yao, Guohua; Lu, Yilin; Ke, Zhigang; Liu, Jinghua; Wu, Yuejin; Yu, Zengliang

    2014-07-01

    Energetic particles exist ubiquitously in nature, and when they hit DNA molecules in organisms, they may induce critical biological effects such as mutation. It is however still a challenge to measure directly and quantitatively the damage imposed by the energetic ions on target DNA molecules. In this work we attempted to employ Fourier transformation infrared (FTIR) spectroscopy to assess the ion-induced direct damage of four nucleic acid bases, namely, thymine (T), cytosine (C), guanine (G), and adenine (A), which are the building blocks of DNA molecules. The samples were prepared as thin films, irradiated by argon ion-beams at raised ion fluences, and in the meantime measured by FTIR spectroscopy for the damage in a quasi-in-situ manner. It was found that the low-energy ion-beam induced radiosensitivity of the four bases shows the sequence G > T > C > A, wherein the possible mechanism was also discussed.

  4. [Research on the analytical line auto-selection for quantitative analysis of materials with laser-induced breakdown spectroscopy].

    PubMed

    Du, Zhen-hui; Meng, Fan-li; Li, Jin-yi; Ma, Yi-wen; Sun, Lan-xiang; Cong, Zhi-bo; Xin, Yong

    2012-04-01

    To realize auto-selection of analytical lines for quantitative analysis of materials with laser-induced breakdown spectroscopy, two parameters, i. e. the relative detected-to-theory intensity ratio (RDTIR) and wavelength difference of detected and theory (WDDT) were defined. The spectral lines seriously disturbed by self-absorption and spectral interference were excluded automatically by setting reasonable thresholds of RDTIR and WDDT. By analyzing the experimental data of high-alloy steel (GBW01605), the analytical lines of iron (Fe), chromium (Cr), nickel (Ni), manganese (Mn) and copper (Cu) were selected, and the results were in line with the principle of lines selection. PMID:22715743

  5. Quantitative description of photoexcited scanning tunneling spectroscopy and its application to the GaAs(110) surface

    NASA Astrophysics Data System (ADS)

    Schnedler, M.; Portz, V.; Weidlich, P. H.; Dunin-Borkowski, R. E.; Ebert, Ph.

    2015-06-01

    A quantitative description of photoexcited scanning tunneling spectra is developed and applied to photoexcited spectra measured on p -doped nonpolar GaAs(110) surfaces. Under illumination, the experimental spectra exhibit an increase of the tunnel current at negative sample voltages only. In order to analyze the experimental data quantitatively, the potential and charge-carrier distributions of the photoexcited tip-vacuum-semiconductor system are calculated by solving the Poisson as well as the hole and electron continuity equations by a finite-difference algorithm. On this basis, the different contributions to the tunnel current are calculated using an extension of the model of Feenstra and Stroscio to include the light-excited carrier concentrations. The best fit of the calculated tunnel currents to the experimental data is obtained for a tip-induced band bending, which is limited by the partial occupation of the C3 surface state by light-excited electrons. The tunnel current at negative voltages is then composed of a valence band contribution and a photoinduced tunnel current of excited electrons in the conduction band. The quantitative description of the tunnel current developed here is generally applicable and provides a solid foundation for the quantitative interpretation of photoexcited scanning tunneling spectroscopy.

  6. Ethane and n-butane oxidation over supported vanadium oxide catalysts: An in situ UV-visible diffuse reflectance spectroscopic investigation

    SciTech Connect

    Gao, X.; Banares, M.A.; Wachs, I.E.

    1999-12-10

    The coordination/oxidation states of surface vanadium oxide species on several oxide supports (Al{sub 2}O{sub 3}, ZrO{sub 2}, SiO{sub 2}) during ethane and n-butane oxidation were examined by in situ UV-vis diffuse reflectance spectroscopy (DRS). Only a small amount of the surface V(V)cations are reduced to V(IV)/V(III) cations under present steady-state reaction conditions. The extents of reduction of the surface V(V) species are a strong function of the specific oxide support, V{sub 2}O{sub 5}/ZrO{sub 2} {gt} V{sub 2}O{sub 5}/Al{sub 2}O{sub 5}/Al{sub 2}O{sub 3} {gt} V{sub 2}O{sub 5}/SiO{sub 2}, and also correlate with their reactivities (turnover frequencies) for ethane and n-butane oxidation reactions. For ZrO{sub 2}-supported samples, the polymerized surface vanadia species were found to be more easily reduced than the isolated surface vanadia species in reducing environments (i.e., ethane or n-butane in He), but no significant differences in the extents of reduction were observed under present steady-state reaction conditions (i.e., ethane/O{sub 2}/He or n-butane/O{sub 2}/He). This observation is also consistent with the ethane oxidation catalytic study, which revealed that the polymerization degree, the domain size, of the surface vanadia species does not appear to significantly affect the reactivity of the supported vanadia catalysts for ethane oxidation.

  7. The aqueous geochemistry of rare earth elements: V. Application of photoacoustic spectroscopy to speciation at low rare earth element concentrations

    Microsoft Academic Search

    Scott A. Wood; C. Drew Tait; David R. Janecky; Term L. Constantopoulos

    1995-01-01

    Photoacoustic spectroscopy (PAS) yields information on complexation identical to that obtainable with conventional UV-visible absorption spectroscopy, but is up to three orders of magnitude more sensitive. The applicability of PAS to the study of Er 3+ oxalate and hydroxide complexes, at 25°C and 1 bar, has been demonstrated. Spectra can be obtained at concentrations as low as 10-20 M, and

  8. The aqueous geochemistry of rare earth elements: V. Application of photoacoustic spectroscopy to speciation at low rare earth element concentrations

    Microsoft Academic Search

    Scott A. Wood; C. Drew Tait; David R. Janecky; Term L. Constantopoulos

    1995-01-01

    Photoacoustic spectroscopy (PAS) yields information on complexation identical to that obtainable with conventional UV-visible absorption spectroscopy, but is up to three orders of magnitude more sensitive. The applicability of PAS to the study of Er3+ oxalate and hydroxide complexes, at 25°C and 1 bar, has been demonstrated. Spectra can be obtained at concentrations as low as 10–20 ?M, and observed

  9. [Study on the application of ridge regression to near-infrared spectroscopy quantitative analysis and optimum wavelength selection].

    PubMed

    Zhang, Man; Liu, Xu-Hua; He, Xiong-Kui; Zhang, Lu-Da; Zhao, Long-Lian; Li, Jun-Hui

    2010-05-01

    In the present paper, taking 66 wheat samples for testing materials, ridge regression technology in near-infrared (NIR) spectroscopy quantitative analysis was researched. The NIR-ridge regression model for determination of protein content was established by NIR spectral data of 44 wheat samples to predict the protein content of the other 22 samples. The average relative error was 0.015 18 between the predictive results and Kjeldahl's values (chemical analysis values). And the predictive results were compared with those values derived through partial least squares (PLS) method, showing that ridge regression method was deserved to be chosen for NIR spectroscopy quantitative analysis. Furthermore, in order to reduce the disturbance to predictive capacity of the quantitative analysis model resulting from irrelevant information, one effective way is to screen the wavelength information. In order to select the spectral information with more content information and stronger relativity with the composition or the nature of the samples to improve the model's predictive accuracy, ridge regression was used to select wavelength information in this paper. The NIR-ridge regression model was established with the spectral information at 4 wavelength points, which were selected from 1 297 wavelength points, to predict the protein content of the 22 samples. The average relative error was 0.013 7 and the correlation coefficient reached 0.981 7 between the predictive results and Kjeldahl's values. The results showed that ridge regression was able to screen the essential wavelength information from a large amount of spectral information. It not only can simplify the model and effectively reduce the disturbance resulting from collinearity information, but also has practical significance for designing special NIR analysis instrument for analyzing specific component in some special samples. PMID:20672604

  10. Polarized light scattering spectroscopy for quantitative measurement of epithelial cellular structures in situ

    Microsoft Academic Search

    Vadim Backman; Rajan Gurjar; Kamran Badizadegan; Irving Itzkan; Ramachandra R. Dasari; Lev T. Perelman; Michael S. Feld

    1999-01-01

    We report an in situ method of probing the structure of living epithelial cells, based on light scattering spectroscopy with polarized light. The method makes it possible to distinguish between single backscattering from uppermost epithelial cells and multiply scattered light. The spectrum of the single backscattering component can be further analyzed to provide histological information about the epithelial cells such

  11. Quantitative micro-analysis by laser-induced breakdown spectroscopy: a review of the experimental approaches

    Microsoft Academic Search

    E. Tognoni; V Palleschi; M Corsi; G Cristoforetti

    2002-01-01

    The laser-induced breakdown spectroscopy (LIBS) technique has shown in recent years its great potential for rapid qualitative analysis of materials. Because of the lack of pre-treatment of the material, as well as the speed of analysis, not mentioning the possibility of in situ analysis, this technique offers an attractive solution for a wide range of industrial applications. As a consequence,

  12. Spectroscopic (FT-IR, FT-Raman and UV-Visible) investigations, NMR chemical shielding anisotropy (CSA) parameters of 2,6-Diamino-4-chloropyrimidine for dye sensitized solar cells using density functional theory

    NASA Astrophysics Data System (ADS)

    Gladis Anitha, E.; Joseph Vedhagiri, S.; Parimala, K.

    2015-02-01

    The molecular structure, geometry optimization, vibrational frequencies of organic dye sensitizer 2,6-Diamino-4-chloropyrimidine (DACP) were studied based on Hartree-Fock (HF) and density functional theory (DFT) using B3LYP methods with 6-311++G(d,p) basis set. Ultraviolet-Visible (UV-Vis) spectrum was investigated by time dependent DFT (TD-DFT). Features of the electronic absorption spectrum in the UV-Visible regions were assigned based on TD-DFT calculation. The absorption bands are assigned to transitions. The interfacial electron transfer between semiconductor TiO2 electrode and dye sensitizer DACP is due to an electron injection process from excited dye to the semiconductor's conduction band. The observed and the calculated frequencies are found to be in good agreement. The energies of the frontier molecular orbitals (FMOS) have also been determined. The chemical shielding anisotropic (CSA) parameters are calculated from the NMR analysis, Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using natural bond orbital (NBO) analysis.

  13. Absolute Quantitation of Bacterial Biofilm Adhesion and Viscoelasticity by Microbead Force Spectroscopy

    E-print Network

    Dutcher, John

    Absolute Quantitation of Bacterial Biofilm Adhesion and Viscoelasticity by Microbead Force of Guelph, Guelph, ON N1G 2W1, Canada ABSTRACT Bacterial biofilms are the most prevalent mode of bacterial stages of biofilm development. Following irreversible attachment of bacterial cells onto a surface

  14. Quantitative determination of the human breast milk macronutrients by near-infrared Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Motta, Edlene d. C. M.; Zângaro, Renato A.; Silveira, Landulfo, Jr.

    2012-03-01

    This work proposes the evaluation of the macronutrient constitution of human breast milk based on the spectral information provided by near-infrared Raman spectroscopy. Human breast milk (5 mL) from a subject was collected during the first two weeks of breastfeeding and stocked in -20°C freezer. Raman spectra were measured using a Raman spectrometer (830 nm excitation) coupled to a fiber based Raman probe. Spectra of human milk were dominated by bands of proteins, lipids and carbohydrates in the 600-1800 cm-1 spectral region. Raman spectroscopy revealed differences in the biochemical constitution of human milk depending on the time of breastfeeding startup. This technique could be employed to develop a classification routine for the milk in Human Milk Banking (HMB) depending on the nutritional facts.

  15. Quantitative Analysis Of Agricultural Parameters Using Ger-imaging-spectroscopy Data Of The Eisac-89 Campagne

    Microsoft Academic Search

    Heike Bach; Wolfram Mauser

    1991-01-01

    During the EISAC-89 Imaging-Spectroscopy Campagne data was acquired of an agricultural test site in the Upper Rhine Valley near the City of Freiburg using the GER-IS-Scanner. An intensive ground-check of plant parameters was carried out of a 24 km2 subset of the acquired image. The ground truth data was integrated in a Geographical Information System. The GER-data was radiometrically corrected

  16. Application of Principal Component-Artificial Neural Networks in Near Infrared Spectroscopy Quantitative Analysis

    Microsoft Academic Search

    Hai-yan Ji; Zhen-hong Rao

    2006-01-01

    \\u000a The principal components of near infrared spectroscopy were calculated by nonlinear iterative partial least squares (NIPALS).\\u000a The best number of principal components was determined by cross-validation method. Thus, limited principal components that\\u000a free from noise and orthogonal each other were obtained. After standardization, these principal components were used as input\\u000a nodes of back propagation artificial neural networks (B-P ANN). ANN

  17. Quantitative antimony speciation in shooting-range soils by EXAFS spectroscopy

    Microsoft Academic Search

    Andreas C. Scheinost; Andre Rossberg; Delphine Vantelon; Irene Xifra; Ruben Kretzschmar; Ann-Kathrin Leuz; Harald Funke; C. Annette Johnson

    2006-01-01

    The Sb speciation in soil samples from Swiss shooting ranges was determined using Sb K-edge X-ray absorption spectroscopy (XAS) and advanced statistical data analysis methods (iterative transformation factor analysis, ITFA). The XAS analysis was supported by a spectral data set of 13 Sb minerals and 4 sorption complexes. In spite of a high variability in geology, soil pH (3.1–7.5), Sb

  18. Quantitative polymorph contaminant analysis in tablets using Raman and near infra-red spectroscopies.

    PubMed

    Hennigan, Michelle C; Ryder, Alan G

    2013-01-01

    The detection and quantification of alternate polymorphs of active pharmaceutical ingredients (APIs), particularly at low concentrations is a key issue for the manufacture and analysis of solid-state formulations. Each polymorph can possess unique physical and chemical properties which in turn can directly affect factors such as solubility and bioavailability. Near infra-red (NIR) and Raman spectroscopies can be used for the rapid characterisation and quantification of polymorphs in solid samples. In this study we have generated a model tablet system with two excipients and a 10% API concentration, where the API is a mixture of the FII and FIII polymorphs of piracetam. Using transmission Raman spectroscopy (TRS) and NIR spectroscopy it was possible to detect FII polymorph contamination in these model tablets with limits of detection (LODs) of 0.6 and 0.7%, respectively, with respect to the total tablet weight (or ?6-7% of the API content). The TRS method is the superior method because of the speed of analysis (?6s per sample), better sampling statistics, and because the sharper, more resolved bands in the Raman spectra allowed for easier interpretation of the spectral data. In addition the TRS used here provides facile access to the low frequency wavenumber region for analysis of solid-state lattice modes. PMID:23146243

  19. Quantitative analysis of bayberry juice acidity based on visible and near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Shao, Yongni; He, Yong; Mao, Jingyuan

    2007-09-01

    Visible and near-infrared (Vis/NIR) reflectance spectroscopy has been investigated for its ability to nondestructively detect acidity in bayberry juice. What we believe to be a new, better mathematic model is put forward, which we have named principal component analysis-stepwise regression analysis-backpropagation neural network (PCA-SRA-BPNN), to build a correlation between the spectral reflectivity data and the acidity of bayberry juice. In this model, the optimum network parameters, such as the number of input nodes, hidden nodes, learning rate, and momentum, are chosen by the value of root-mean-square (rms) error. The results show that its prediction statistical parameters are correlation coefficient (r) of 0.9451 and root-mean-square error of prediction (RMSEP) of 0.1168. Partial least-squares (PLS) regression is also established to compare with this model. Before doing this, the influences of various spectral pretreatments (standard normal variate, multiplicative scatter correction, S. Golay first derivative, and wavelet package transform) are compared. The PLS approach with wavelet package transform preprocessing spectra is found to provide the best results, and its prediction statistical parameters are correlation coefficient (r) of 0.9061 and RMSEP of 0.1564. Hence, these two models are both desirable to analyze the data from Vis/NIR spectroscopy and to solve the problem of the acidity prediction of bayberry juice. This supplies basal research to ultimately realize the online measurements of the juice's internal quality through this Vis/NIR spectroscopy technique.

  20. quantitative determination of the AGN content in local ULIRGs through L-band spectroscopy

    E-print Network

    Risaliti, G; Sani, E

    2009-01-01

    We present a quantitative estimate of the relative AGN/starburst content in a sample of 59 nearby (z85% of the observed infrared luminosity. The subsample of sources optically classified as LINERs (31 objects) shows a similar AGN/starburst distribution as the whole sample, indicating a composite nature for this class of objects. We also show that a few ULIRGs, optically classified as starbursts, have L-band spectral features suggesting the presence of a buried AGN.

  1. Quantitative Determination of Chemical Processes by Dynamic Nuclear Polarization Enhanced Nuclear Magnetic Resonance Spectroscopy

    E-print Network

    Zeng, Haifeng

    2012-07-16

    between two spins, gives rise to the nuclear Overhauser effect (NOE),2-3 which depends on the distance between the two spins as 61/ij ijNOE r? . Distances obtained from NOE measurement and dihedral angles from scalar couplings provide geometrical... Robert R. Lucchese Jim(Xiuquan) Ji Head of Department, David H. Russell May 2012 Major Subject: Chemistry iii ABSTRACT Quantitative Determination of Chemical Processes by Dynamic Nuclear Polarization Enhanced Nuclear Magnetic Resonance...

  2. Measurement technique of electric field using ultraviolet/visible spectroscopy in cylindrical plasmas

    SciTech Connect

    Kobayashi, T.; Yoshikawa, M.; Kubota, Y.; Saito, M.; Numada, M.; Ishii, K.; Cho, T. [Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan)

    2004-10-01

    The rotation of impurity ion has been measured using ultraviolet (UV) visible spectroscopy in the cylindrical fusion plasma GAMMA 10 to investigate diamagnetic drift and ExB drift. The electric field is estimated with the plasma rotation and ExB drift analysis. Since the detected signal is the line integrated emission, the parametric Abel inversion technique has been developed. In the method, a density profile of impurity ion was assumed. Recently, we can obtain the density profile using collisional-radiative model (CRM) calculation. Then the electric field is obtained independently of that assumption. We present the measurement technique of the electric field using UV/visible spectroscopy and CRM calculation. The experimental result in GAMMA 10 is that consistent with the result of the neutral beam probe measurement.

  3. Distribution of Hydroxyl Groups in Kukersite Shale Oil: Quantitative Determination Using Fourier Transform Infrared (FT-IR) Spectroscopy.

    PubMed

    Baird, Zachariah Steven; Oja, Vahur; Järvik, Oliver

    2015-05-01

    This article describes the use of Fourier transform infrared (FT-IR) spectroscopy to quantitatively measure the hydroxyl concentrations among narrow boiling shale oil cuts. Shale oil samples were from an industrial solid heat carrier retort. Reference values were measured by titration and were used to create a partial least squares regression model from FT-IR data. The model had a root mean squared error (RMSE) of 0.44 wt% OH. This method was then used to study the distribution of hydroxyl groups among more than 100 shale oil cuts, which showed that hydroxyl content increased with the average boiling point of the cut up to about 350 °C and then leveled off and decreased. PMID:25811170

  4. Spatial modulation spectroscopy for imaging and quantitative analysis of single dye-doped organic nanoparticles inside cells.

    PubMed

    Devadas, Mary Sajini; Devkota, Tuphan; Guha, Samit; Shaw, Scott K; Smith, Bradley D; Hartland, Gregory V

    2015-06-01

    Imaging of non-fluorescent nanoparticles in complex biological environments, such as the cell cytosol, is a challenging problem. For metal nanoparticles, Rayleigh scattering methods can be used, but for organic nanoparticles, such as dye-doped polymer beads or lipid nanoparticles, light scattering does not provide good contrast. In this paper, spatial modulation spectroscopy (SMS) is used to image single organic nanoparticles doped with non-fluorescent, near-IR croconaine dye. SMS is a quantitative imaging technique that yields the absolute extinction cross-section of the nanoparticles, which can be used to determine the number of dye molecules per particle. SMS images were recorded for particles within EMT-6 breast cancer cells. The measurements allowed mapping of the nanoparticle location and the amount of dye in a single cell. The results demonstrate how SMS can facilitate efforts to optimize dye-doped nanoparticles for effective photothermal therapy of cancer. PMID:25964049

  5. Quantitative analysis of bayberry juice acidity based on visible and near-infrared spectroscopy

    SciTech Connect

    Shao Yongni; He Yong; Mao Jingyuan

    2007-09-01

    Visible and near-infrared (Vis/NIR) reflectance spectroscopy has been investigated for its ability to nondestructively detect acidity in bayberry juice. What we believe to be a new, better mathematic model is put forward, which we have named principal component analysis-stepwise regression analysis-backpropagation neural network (PCA-SRA-BPNN), to build a correlation between the spectral reflectivity data and the acidity of bayberry juice. In this model, the optimum network parameters,such as the number of input nodes, hidden nodes, learning rate, and momentum, are chosen by the value of root-mean-square (rms) error. The results show that its prediction statistical parameters are correlation coefficient (r) of 0.9451 and root-mean-square error of prediction(RMSEP) of 0.1168. Partial least-squares (PLS) regression is also established to compare with this model. Before doing this, the influences of various spectral pretreatments (standard normal variate, multiplicative scatter correction, S. Golay first derivative, and wavelet package transform) are compared. The PLS approach with wavelet package transform preprocessing spectra is found to provide the best results, and its prediction statistical parameters are correlation coefficient (r) of 0.9061 and RMSEP of 0.1564. Hence, these two models are both desirable to analyze the data from Vis/NIR spectroscopy and to solve the problem of the acidity prediction of bayberry juice. This supplies basal research to ultimately realize the online measurements of the juice's internal quality through this Vis/NIR spectroscopy technique.

  6. Qualitative and quantitative study of polymorphic forms in drug formulations by near infrared FT-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Auer, Martin E.; Griesser, Ulrich J.; Sawatzki, Juergen

    2003-12-01

    Near infrared FT-Raman spectroscopy was applied for the determination of polymorphic forms in a number of commercial drug products containing the polymorphic drug compounds sorbitol, mannitol, famotidine, acemetacin, carbamazepine, meprobamate and phenylbutazone. The crystal forms present in the drug products were identified based on the position, intensity and shape of characteristic bands. Quantitative analysis of a mixture of two crystal forms of mannitol in a drug product was carried out using a partial least-squares method. In drug products containing meprobamate, sorbitol, and carbamazepine, the thermodynamically stable form was found exclusively, whereas metastable polymorphs were found in solid dosage forms of acemetacin, phenylbutazone, famotidine and mannitol. A mixture of two polymorphic forms of mannitol in Lipobay tablets was determined to consist of 30.8±3.8% of the metastable modification I. The simple sample preparation, the occurrence of sharp bands in the spectra as well as the high reproducibility and accuracy qualifies FT-Raman spectroscopy for the identification and quantification of crystal forms in drug products. The method is perfectly suited to meet the regulatory requirements of monitoring crystal forms during processing and storage and often succeeds in detecting the present crystal form in drug products even when the used excipients are not known.

  7. Simultaneous quantitative analysis of mebendazole polymorphs A-C in powder mixtures by DRIFTS spectroscopy and ANN modeling.

    PubMed

    Kachrimanis, K; Rontogianni, M; Malamataris, S

    2010-02-01

    In the present study, a simple method, based on diffuse reflectance FTIR spectroscopy (DRIFTS) and artificial neural network (ANN) modeling is developed for the simultaneous quantitative analysis of mebendazole polymorphs A-C in powder mixtures. Spectral differences between the polymorphs are elucidated by computationally assisted band assignments on the basis of quantum chemical calculations, and subsequently, the spectra are preprocessed by calculation of 1st and 2nd derivatives. Then ANN models are fitted after PCA compression of the input space. Finally the predictive performance of the ANNs is compared with that of PLS regression. It was found that simultaneous quantitative analysis of forms A-C in powder mixtures is possible by fitting an ANN model to the 2nd derivative spectra even after PCA compression of the data (RMSEP of 1.75% for form A, 1.85% for B, and 1.65% for C), while PLS regression, applied for comparison purposes, results in acceptable predictions only within the 700-1750cm(-1) spectral range and after direct orthogonal signal correction (DOSC), with RMSEP values of 2.69%, 2.68%, and 3.40% for forms A, B, and C, respectively. Application of the ANN to commercial samples of raw material and formulation (suspension) proved its suitability for the prediction of polymorphic content. PMID:19833468

  8. Compartment syndrome: A quantitative study of high-energy phosphorus compounds using sup 31 P-magnetic resonance spectroscopy

    SciTech Connect

    Heppenstall, R.B.; Sapega, A.A.; Izant, T.; Fallon, R.; Shenton, D.; Park, Y.S.; Chance, B. (Veterans Administration Medical Center, Philadelphia, PA (USA))

    1989-08-01

    The purpose of this study was to quantitate the intracellular high-energy phosphate compounds during 6 hours of tissue ischemia in the anterior tibial compartment of beagles subjected to an induced traumatized compartment syndrome. The goal of this work was to provide clinicians with objective criteria to augment clinical judgment regarding surgical intervention in the impending compartment syndrome. A beagle model was utilized in which the Delta pressure (difference between the mean arterial pressure and compartment pressure) could be controlled. The model, in conjunction with {sup 31}P-magnetic resonance spectroscopy (MRS), allowed a measure of high-energy phosphate compounds and pH in the compartment at various Delta pressures. The extent of ischemic metabolic insult in the compartment was then quantitated. Our data suggest the following: (1) lower Delta pressures result in a proportionally greater drop in the intracellular phosphocreatine ratio and pH; (2) at lower Delta pressures, there is proportionally greater decline in the percentage recovery post-fasciotomy; (3) blood pressure is extremely important and periods of hypotension may result in increased muscle damage at lower compartment pressures.

  9. A Comparison of Multivariate and Pre-Processing Methods for Quantitative Laser-Induced Breakdown Spectroscopy of Geologic Samples

    NASA Technical Reports Server (NTRS)

    Anderson, R. B.; Morris, R. V.; Clegg, S. M.; Bell, J. F., III; Humphries, S. D.; Wiens, R. C.

    2011-01-01

    The ChemCam instrument selected for the Curiosity rover is capable of remote laser-induced breakdown spectroscopy (LIBS).[1] We used a remote LIBS instrument similar to ChemCam to analyze 197 geologic slab samples and 32 pressed-powder geostandards. The slab samples are well-characterized and have been used to validate the calibration of previous instruments on Mars missions, including CRISM [2], OMEGA [3], the MER Pancam [4], Mini-TES [5], and Moessbauer [6] instruments and the Phoenix SSI [7]. The resulting dataset was used to compare multivariate methods for quantitative LIBS and to determine the effect of grain size on calculations. Three multivariate methods - partial least squares (PLS), multilayer perceptron artificial neural networks (MLP ANNs) and cascade correlation (CC) ANNs - were used to generate models and extract the quantitative composition of unknown samples. PLS can be used to predict one element (PLS1) or multiple elements (PLS2) at a time, as can the neural network methods. Although MLP and CC ANNs were successful in some cases, PLS generally produced the most accurate and precise results.

  10. Quantitative analysis of carbonaceous aerosols using Laser-Induced Breakdown Spectroscopy: A study on mass loading induced plasma matrix effects.

    SciTech Connect

    Mukherjee, Dibyendu [ORNL; Cheng, Mengdawn [ORNL

    2008-01-01

    We present results indicating mass loading induced plasma matrix effects on the application of quantitative laser-induced breakdown spectroscopy (LIBS) for estimation of carbon contents in aerosols. An in-house flow-controlled powder-dispersion system generated carbonaceous aerosols with varying bi-modal particle size distributions ({approx} 1 {micro}m and 10 {micro}m median diameters), thereby resulting in a wide mass loading range. For ease of chemical handling and to eliminate toxic effects, common talcum powder was used as our standard aerosol. Normalized atomic species concentrations of C, i.e., (C)/(Si) ratios, were calculated from atomic emission lines of C I (248 nm), Si I (252 nm), and plasma temperatures estimated from a series of Mg I lines. The results show a decrease in (C)/(Si) ratio to about 65% of the initial value as relative mass loadings increased (5.5-100%) due to the increase in number concentrations of larger sized particles ({approx}10 {micro}m median diameter). As a comparison, normalized ratio of (Mg)/(Si) did not exhibit any marked change with increased mass loading. The normalized total absorption of photon flux across the C I (248 nm) spectral line indicated a strong correlation to the percentage decrease in (C)/(Si) ratio. We used an impactor with a cut-off size of around 10 {micro}m diameter to generate mono-modal aerosolized powders ({approx}1 {micro}m median diameter) that had lower relative mass loadings (0.32-0.16%). Similar LIBS analysis on these did not indicate any of the matrix effects. We conclude that for aerosol systems with widely varying mass loadings, quantitative LIBS analysis can be significantly affected by plasma matrix effects, specifically for the C I (248 nm) emission line as noticed in this study. This bears significance for the application of quantitative LIBS in the chemical characterization of all forms of carbonaceous aerosols.

  11. UV\\/visible albedos from airborne measurements

    Microsoft Academic Search

    A. Webb; A. Kylling; I. Stromberg

    2003-01-01

    During the INSPECTRO campaign effective surface albedo was measured at UV and visible wavelengths from two airborne platforms, a Cessna light aircraft and a hot air balloon. On board the Cessna was a scanning spectroradiometer measuring from 300 - 500nm at 10nm intervals. The NILU cube, with 6 faces and two UV channels at 312 and 340nm, was suspended beneath

  12. Quantum mechanical study and spectroscopic (FT-IR, FT-Raman, UV-Visible) study, potential energy surface scan, Fukui function analysis and HOMO-LUMO analysis of 3-tert-butyl-4-methoxyphenol by DFT methods

    NASA Astrophysics Data System (ADS)

    Saravanan, S.; Balachandran, V.

    2014-09-01

    This study represents an integral approach towards understanding the electronic and structural aspects of 3-tert-butyl-4-methoxyphenol (TBMP). Fourier-transform Infrared (FT-IR) and Fourier-transform Raman (FT-Raman) spectra of TBMP was recorded in the region 4000-400 cm-1 and 3500-100 cm-1, respectively. The molecular structures, vibrational wavenumbers, infrared intensities and Raman activities were calculated using DFT (B3LYP and LSDA) methods using 6-311++G (d,p) basis set. The most stable conformer of TBMP was identified from the computational results. The assignments of vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The first order hyperpolarizability (?0) and related properties (?, ?0 and ??) of TBMP have been discussed. The stability and charge delocalization of the molecule was studied by Natural Bond Orbital (NBO) analysis. UV-Visible spectrum and effects of solvents have been discussed and the electronic properties such as HOMO and LUMO energies were determined by time-dependent TD-DFT approach with B3LYP/6-311++G (d,p) level of theory. The molecule orbital contributions are studied by density of energy states (DOSs). The reactivity sites are identified by mapping the electron density into electrostatic potential surface (MEP). Mulliken analysis of atomic charges is also calculated. The thermodynamic properties at different temperatures were calculated, revealing the correlations between standard heat capacities, standard entropy and standard enthalpy changes with temperatures. Global hardness, global softness, global electrophilicity and ionization potential of the title compound are determined.

  13. Quantum mechanical study and spectroscopic (FT-IR, FT-Raman, UV-Visible) study, potential energy surface scan, Fukui function analysis and HOMO-LUMO analysis of 3-tert-butyl-4-methoxyphenol by DFT methods.

    PubMed

    Saravanan, S; Balachandran, V

    2014-09-15

    This study represents an integral approach towards understanding the electronic and structural aspects of 3-tert-butyl-4-methoxyphenol (TBMP). Fourier-transform Infrared (FT-IR) and Fourier-transform Raman (FT-Raman) spectra of TBMP was recorded in the region 4000-400 cm(-1) and 3500-100 cm(-1), respectively. The molecular structures, vibrational wavenumbers, infrared intensities and Raman activities were calculated using DFT (B3LYP and LSDA) methods using 6-311++G (d,p) basis set. The most stable conformer of TBMP was identified from the computational results. The assignments of vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The first order hyperpolarizability (?0) and related properties (?, ?0 and ??) of TBMP have been discussed. The stability and charge delocalization of the molecule was studied by Natural Bond Orbital (NBO) analysis. UV-Visible spectrum and effects of solvents have been discussed and the electronic properties such as HOMO and LUMO energies were determined by time-dependent TD-DFT approach with B3LYP/6-311++G (d,p) level of theory. The molecule orbital contributions are studied by density of energy states (DOSs). The reactivity sites are identified by mapping the electron density into electrostatic potential surface (MEP). Mulliken analysis of atomic charges is also calculated. The thermodynamic properties at different temperatures were calculated, revealing the correlations between standard heat capacities, standard entropy and standard enthalpy changes with temperatures. Global hardness, global softness, global electrophilicity and ionization potential of the title compound are determined. PMID:24813291

  14. Near-infrared spectroscopy quantitative determination of Pefloxacin mesylate concentration in pharmaceuticals by using partial least squares and principal component regression multivariate calibration

    Microsoft Academic Search

    Yunfei Xie; Yan Song; Yong Zhang; Bing Zhao

    2010-01-01

    Pefloxacin mesylate, a broad-spectrum antibacterial fluoroquinolone, has been widely used in clinical practice. Therefore, it is very important to detect the concentration of Pefloxacin mesylate. In this research, the near-infrared spectroscopy (NIRS) has been applied to quantitatively analyze on 108 injection samples, which was divided into a calibration set containing 89 samples and a prediction set containing 19 samples randomly.

  15. The assessment of chromophores in bleached cellulosic pulps employing UV-Raman spectroscopy.

    PubMed

    Loureiro, Pedro E G; Fernandes, António J S; Carvalho, M Graça V S; Evtuguin, Dmitry V

    2010-07-01

    UV-Resonance Raman (UV-RR) coupled with UV-visible Diffuse Reflectance (UV-vis DR) spectroscopy was applied to a solid-state study of chromophores in Eucalyptus globulus kraft cellulosic pulps bleached by chlorine dioxide and hydrogen peroxide. The UV-RR spectra were acquired at 325nm laser beam excitation, which was shown to be appropriate for selective analysis of chromophore structures in polysaccharides. The proposed approach allowed the monitoring of chromophores in pulps and to track the extent of polysaccharide oxidation. However, precaution was suggested while performing a quantitative analysis of chromophores at the characteristic band of approximately 1600cm(-1) because of charge transfer complexes (CTCs) that exist in the pulp. These CTCs can affect the intensity of the aforementioned band by diminishing the conjugate state in the chromophore moieties. The amount of carbonyl and carboxyl groups in polysaccharides correlated with the intensity of the band at 1093cm(-1). The analysis of UV-RR spectra revealed xylan as an important source of chromophores in eucalypt kraft pulp. PMID:20334853

  16. [Rapid quantitative analysis of hydrocarbon composition of furfural extract oils using attenuated total reflection infrared spectroscopy].

    PubMed

    Li, Na; Yuan, Hong-Fu; Hu, Ai-Qin; Liu, Wei; Song, Chun-Feng; Li, Xiao-Yu; Song, Yi-Chang; He, Qi-Jun; Liu, Sha; Xu, Xiao-Xuan

    2014-07-01

    A set of rapid analysis system for hydrocarbon composition of heavy oils was designed using attenuated total reflection FTIR spectrometer and chemometrics to determine the hydrocarbon composition of furfural extract oils. Sixty two extract oil samples were collected and their saturates and aromatics content data were determined according to the standard NB/SH/T0509-2010, then the total contents of resins plus asphaltenes were calculated by the subtraction method in the percentage of weight. Based on the partial least squares (PLS), calibration models for saturates, aromatics, and resin+asphaltene contents were established using attenuated total reflection FTIR spectroscopy, with their SEC, 1.43%, 0.91% and 1.61%, SEP, 1.56%, 1.24% and 1.81%, respectively, meeting the accuracy and repeatability required for the standard. Compared to the present standard method, the efficiency of hydrocarbon composition analysis for furfural extract oils is significantly improved by the new method which is rapid and simple. The system could also be used for other heavy oil analysis, with excellent extension and application foreground. PMID:25269288

  17. Quantitation of cerebral blood volume in human infants by near-infrared spectroscopy.

    PubMed

    Wyatt, J S; Cope, M; Delpy, D T; Richardson, C E; Edwards, A D; Wray, S; Reynolds, E O

    1990-03-01

    Current methods for measuring cerebral blood volume (CBV) in newborn infants are unsatisfactory. A new method is described in which the effect of a small change (5-10%) in arterial oxygen saturation (SaO2) on cerebral oxyhemoglobin [HbO2] and deoxyhemoglobin [Hb] concentration is observed by near-infrared (NIR) spectroscopy. Previous experiments in which the NIR absorption characteristics of HbO2 and Hb and the pathlength of NIR light through the brain were defined allowed changes in [HbO2] and [Hb] to be quantified from the Beer-Lambert law. It is shown here that CBV can then be derived from the expression CBV = (delta[HbO2] - delta[Hb])/(2. delta SaO2.H.R.), where H is the large vessel total hemoglobin concentration and R to the cerebral-to-large vessel hematocrit ratio. Observations on 12 newborn infants with normal brains, born at 25-40 wk of gestation and aged 10-240 h, gave a mean value for CBV of 2.22 +/- 0.40 (SD) ml/100 g, whereas mean CBV was significantly higher 3.00 +/- 1.04 ml/100 g in 10 infants with brain injury born at 24 to 42 wk of gestation and aged 4-168 h (P less than 0.05). PMID:2341336

  18. [Quantitative study on errors in evaluation of trace gases by long path differential optical absorption spectroscopy].

    PubMed

    Li, Su-Wen; Liu, Wen-Qing; Xie, Pin-Hua; Zhang, Yu-Jun; Li, Ang; Chen, Teng-Yun

    2007-07-01

    Long path differential optical absorption spectroscopy (LP-DOAS) can be used to retrieve the concentration of trace gases based on the principle of least squares. LP-DOAS permits the sensitive measurement of concentrations of trace gases. However, the calculation of a statistically sound measurement precision still remains an unsolved problem. The absorbance of atmospheric trace gases is usually very weak, so the interference caused by the occurrence of non-reproducible spectral artifacts often determines the detection limit and the measurement precision. These spectral artifacts bias the least squares fitting result in two respects. Spectral artifacts are falsely interpreted as real absorption, and spectral artifacts add non-statistical noise to spectral residuals, resulting in a significant underestimation of the least squares fitting error. Monte Carlo method was presented to investigate the evaluation errors in DOAS spectra accurately. Residual inspection by cyclic displacement was used to estimate the effect of false interpretation of the artifact structures. The evaluation of simulated atmospheric measurement spectra shows that Monte Carlo method yields a good estimate of the spectra evaluation error. It is approximately real error, factors of errors are 1.13, but errors are ordinarily underestimated by err(LSQ), and factors of errors are 3.12. PMID:17944388

  19. Microfluidic impedance spectroscopy as a tool for quantitative biology and biotechnology

    PubMed Central

    Sabuncu, Ahmet C.; Zhuang, Jie; Kolb, Juergen F.; Beskok, Ali

    2012-01-01

    A microfluidic device that is able to perform dielectric spectroscopy is developed. The device consists of a measurement chamber that is 250??m thick and 750??m in radius. Around 1000 cells fit inside the chamber assuming average quantities for cell radius and volume fraction. This number is about 1000 folds lower than the capacity of conventional fixtures. A T-cell leukemia cell line Jurkat is tested using the microfluidic device. Measurements of deionized water and salt solutions are utilized to determine parasitic effects and geometric capacitance of the device. Physical models, including Maxwell-Wagner mixture and double shell models, are used to derive quantities for sub-cellular units. Clausius-Mossotti factor of Jurkat cells is extracted from the impedance spectrum. Effects of cellular heterogeneity are discussed and parameterized. Jurkat cells are also tested with a time domain reflectometry system for verification of the microfluidic device. Results indicate good agreement of values obtained with both techniques. The device can be used as a unique cell diagnostic tool to yield information on sub-cellular units. PMID:23853680

  20. Quantitative endoscopic imaging elastic scattering spectroscopy: model system/tissue phantom validation

    NASA Astrophysics Data System (ADS)

    Lindsley, E. H.; Farkas, D. L.

    2008-02-01

    We have designed and built an imaging elastic scattering spectroscopy endoscopic instrument for the purpose of detecting cancer in vivo. As part of our testing and validation of the system, known targets representing potential disease states of interest were constructed using polystyrene beads of known average diameter and TiO II crystals embedded in a two-layer agarose gel. Final construction geometry was verified using a dissection microscope. The phantoms were then imaged using the endoscopic probe at a known incident angle, and the results compared to model predictions. The mathematical model that was used combines classic ray-tracing optics with Mie scattering to predict the images that would be observed by the probe at a given physical distance from a Mie-regime scattering media. This model was used generate the expected observed response for a broad range of parameter values, and these results were then used as a library to fit the observed data from the phantoms. Compared against the theoretical library, the best matching signal correlated well with known phantom material dimensions. These results lead us to believe that imaging elastic scattering can be useful in detection/diagnosis, but further refinement of the device will be necessary to detect the weak signals in a real clinical setting.

  1. Heterogeneous nanostructures for plasmonic interaction with luminescence and quantitative surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Das, Gautom K.; Sudheendra, L.; Kennedy, Ian M.

    2014-03-01

    NIR-to-visible up-conversion nanomaterials have been investigated in many promising applications including nextgeneration displays, solar cells, and biological labels. When doped with different trivalent lanthanide ions, NaYF4 nanoparticles can produce up-converted emission from visible to infra-red wavelengths. However, the quantum yield of this class of materials is low. Noble metals in the vicinity of the phosphor can increase the phosphorescence by local field enhancement due to plasmonic resonances, and by modification of the radiative rate of the phosphor. Most previous studies have investigated the phenomenon by placing nanophosphors onto a metal substrate, or by fabrication of nano structures with spacers such as polymers, dielectric materials (silica). By contrast, we have studied the interaction between the luminescence and the surface plasmon using a core-shell type nanostructure where a uniform shell of silver is shown to grown on doped-NaYF4 nanophosphors by Ostwald ripening. We further demonstrate the proximity effect of metal-enhanced luminescence by exciting an undoped NaYF4 shell. The result shows a significant synergistic enhancement of up-conversion luminescence due to the active shell as spacer layer. In addition, we have shown this novel nanostructure may be useful in surface-enhanced Raman spectroscopy (SERS).

  2. Fast quantitative determination of microbial rhamnolipids from cultivation broths by ATR-FTIR Spectroscopy

    PubMed Central

    Leitermann, Frank; Syldatk, Christoph; Hausmann, Rudolf

    2008-01-01

    Background Vibrational spectroscopic techniques are becoming increasingly important and popular because they have the potential to provide rapid and convenient solutions to routine analytical problems. Using these techniques, a variety of substances can be characterized, identified and also quantified rapidly. Results The rapid ATR-FTIR (Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy) in time technique has been applied, which is suitable to quantify the concentrations of microbial rhamnolipids in a typical cultivation process. While the usually applied HPLC analysis requires an extensive and time consuming multi step extraction protocol for sample preparation, the ATR-FTIR-method allows the quantification of the rhamnolipids within 20 minutes. Accuracies between 0.5 g/l – 2.1 g/l for the different analytes were determined by cross validation of the calibration set. Even better accuracies between 0.28 g/l – 0.59 g/l were found for independent test samples of an arbitrarily selected cultivation. Conclusion ATR-FTIR was found to be suitable for the rapid analysis of rhamnolipids in a biotechnological process with good reproducibility in sample determination and sufficient accuracy. An improvement in accuracy through continuous expansion and validation of the reference spectra set seems very likely. PMID:18840269

  3. Metabolic responses during hemodialysis determined by quantitative (1)H NMR spectroscopy.

    PubMed

    Fujiwara, Masako; Ando, Itiro; Takeuchi, Kazuhisa; Oguma, Shiro; Sato, Hiroshi; Sekino, Hiroshi; Sato, Keisuke; Imai, Yutaka

    2015-07-10

    A large proportion of patients with end-stage renal disease have lifelong hemodialysis (HD) treatment. HD rapidly and indiscriminately removes necessary small metabolites together with uremic toxins from plasma into dialysate. To investigate metabolic responses to HD, we determined the levels of metabolites through time-course monitoring of (1)H NMR spectroscopy of dialysate during HD. The dialysate sample is stable for analysis because it contains only small metabolites without proteins. It was collected non-invasively from 9 HD patients with chronic glomerular nephropathy, at 6 time points during 4h of HD in 5 sessions. Creatinine, alanine, lactate, pyruvate and valine were simultaneously quantified on a one-dimensional single-pulse spectrum with a single standard compound. The concentration of creatinine exhibited monotonous decay with time, while that of valine decreased slowly and then maintained its levels throughout an HD. Lactate, alanine and pyruvate increased at 2-3h after the initiation of HD. They exhibited remarkable responses to HD with production from the body. The time-course of change in the 4 metabolites of lactate, pyruvate, alanine, and valine had reproducible behavior unique to each patient during the HD. This finding may be applied to distinguish metabolic status in HD patients. PMID:25886393

  4. Fiber optic based multiparametric spectroscopy in vivo: Toward a new quantitative tissue vitality index

    NASA Astrophysics Data System (ADS)

    Kutai-Asis, Hofit; Barbiro-Michaely, Efrat; Deutsch, Assaf; Mayevsky, Avraham

    2006-02-01

    In our previous publication (Mayevsky et al SPIE 5326: 98-105, 2004) we described a multiparametric fiber optic system enabling the evaluation of 4 physiological parameters as indicators of tissue vitality. Since the correlation between the various parameters may differ in various pathophysiological conditions there is a need for an objective quantitative index that will integrate the relative changes measured in real time by the multiparametric monitoring system into a single number-vitality index. Such an approach to calculate tissue vitality index is critical for the possibility to use such an instrument in clinical environments. In the current presentation we are reporting our preliminary results indicating that calculation of an objective tissue vitality index is feasible. We used an intuitive empirical approach based on the comparison between the calculated index by the computer and the subjective evaluation made by an expert in the field of physiological monitoring. We used the in vivo brain of rats as an animal model in our current studies. The rats were exposed to anoxia, ischemia and cortical spreading depression and the responses were recorded in real time. At the end of the monitoring session the results were analyzed and the tissue vitality index was calculated offline. Mitochondrial NADH, tissue blood flow and oxy-hemoglobin were used to calculate the vitality index of the brain in vivo, where each parameter received a different weight, in each experiment type based on their significance. It was found that the mitochondrial NADH response was the main factor affected the calculated vitality index.

  5. Quantitation of ten 30S ribosomal assembly intermediates using fluorescence triple correlation spectroscopy.

    PubMed

    Ridgeway, William K; Millar, David P; Williamson, James R

    2012-08-21

    The self-assembly of bacterial 30S ribosomes involves a large number of RNA folding and RNA-protein binding steps. The sequence of steps determines the overall assembly mechanism and the structure of the mechanism has ramifications for the robustness of biogenesis and resilience against kinetic traps. Thermodynamic interdependencies of protein binding inferred from omission-reconstitution experiments are thought to preclude certain assembly pathways and thus enforce ordered assembly, but this concept is at odds with kinetic data suggesting a more parallel assembly landscape. A major challenge is deconvolution of the statistical distribution of intermediates that are populated during assembly at high concentrations approaching in vivo assembly conditions. To specifically resolve the intermediates formed by binding of three ribosomal proteins to the full length 16S rRNA, we introduce Fluorescence Triple-Correlation Spectroscopy (F3CS). F3CS identifies specific ternary complexes by detecting coincident fluctuations in three-color fluorescence data. Triple correlation integrals quantify concentrations and diffusion kinetics of triply labeled species, and F3CS data can be fit alongside auto-correlation and cross-correlation data to quantify the populations of 10 specific ribosome assembly intermediates. The distribution of intermediates generated by binding three ribosomal proteins to the entire native 16S rRNA included significant populations of species that were not previously thought to be thermodynamically accessible, questioning the current interpretation of the classic omission-reconstitution experiments. F3CS is a general approach for analyzing assembly and function of macromolecular complexes, especially those too large for traditional biophysical methods. PMID:22869699

  6. Qualitative and quantitative determination of human biomarkers by laser photoacoustic spectroscopy methods

    NASA Astrophysics Data System (ADS)

    Popa, C.; Bratu, A. M.; Matei, C.; Cernat, R.; Popescu, A.; Dumitras, D. C.

    2011-07-01

    The hypothesis that blood, urine and other body fluids and tissues can be sampled and analyzed to produce clinical information for disease diagnosis or therapy monitoring is the basis of modern clinical diagnosis and medical practice. The analysis of breath air has major advantages because it is a non-invasive method, represents minimal risk to personnel collecting the samples and can be often sampled. Breath air samples from the human subjects were collected using aluminized bags from QuinTron and analyzed using the laser photoacoustic spectroscopy (LPAS) technique. LPAS is used to detect traces of ethylene in breath air resulting from lipid peroxidation in lung epithelium following the radiotherapy and also traces of ammonia from patients subjected to hemodialysis for treatment of renal failure. In the case of patients affected by cancer and treated by external radiotherapy, all measurements were done at 10P(14) CO2 laser line, where the ethylene absorption coefficient has the largest value (30.4 cm-1 atm-1), whereas for patients affected by renal failure and treated by standard dialysis, all measurements were performed at 9R(30) CO2 laser line, where the ammonia absorption coefficient has the maximum value of 57 cm-1 atm-1. The levels of ethylene and ammonia in exhaled air, from patients with cancer and renal failure, respectively, were measured and compared with breath air contents from healthy humans. Human gas biomarkers were measured at sub-ppb (parts per billion) concentration sensitivities. It has been demonstrated that LPAS technique will play an important role in the future of exhaled breath air analysis. The key attributes of this technique are sensitivity, selectivity, fast and real time response, as well as its simplicity.

  7. Quantitative Physiology of the Precancerous Cervix In Vivo through Optical Spectroscopy1

    PubMed Central

    Chang, Vivide Tuan-Chyan; Cartwright, Peter S; Bean, Sarah M; Palmer, Greg M; Bentley, Rex C; Ramanujam, Nirmala

    2009-01-01

    Cervical cancer is the second most common female cancer worldwide. The ability to quantify physiological and morphological changes in the cervix is not only useful in the diagnosis of cervical precancers but also important in aiding the design of cost-effective detection systems for use in developing countries that lack well-established screening and diagnostic programs. We assessed the capability of a diffuse reflectance spectroscopy technique to identify contrasts in optical biomarkers that vary with different grades of cervical intraepithelial neoplasia (CIN) from normal cervical tissues. The technology consists of an optical probe and an instrument (with broadband light source, dispersive element, and detector), and a Monte Carlo algorithm to extract optical biomarker contributions including total hemoglobin (Hb) concentration, Hb saturation, and reduced scattering coefficient from the measured spectra. Among 38 patients and 89 sites examined, 46 squamous normal sites, 18 CIN 1, and 15 CIN 2+ sites were included in the analysis. Total Hb was statistically higher in CIN 2+ (18.3 ± 3.6 µM, mean ± SE) compared with normal (9.58 ± 1.91 µM) and CIN 1 (12.8 ± 2.6 µM), whereas scattering was significantly reduced in CIN 1 (8.3 ± 0.8 cm-1) and CIN 2+ (8.6 ± 1.0 cm-1) compared with normal (10.2 ± 1.1 cm-1). Hemoglobin saturation was not significantly altered in CIN 2+ compared with normal and CIN 1. The difference in total Hb is likely because of stromal angiogenesis, whereas decreased scattering can be attributed to breakdown of collagen network in the cervical stroma. PMID:19308287

  8. Spatial modulation spectroscopy for imaging and quantitative analysis of single dye-doped organic nanoparticles inside cells

    NASA Astrophysics Data System (ADS)

    Devadas, Mary Sajini; Devkota, Tuphan; Guha, Samit; Shaw, Scott K.; Smith, Bradley D.; Hartland, Gregory V.

    2015-05-01

    Imaging of non-fluorescent nanoparticles in complex biological environments, such as the cell cytosol, is a challenging problem. For metal nanoparticles, Rayleigh scattering methods can be used, but for organic nanoparticles, such as dye-doped polymer beads or lipid nanoparticles, light scattering does not provide good contrast. In this paper, spatial modulation spectroscopy (SMS) is used to image single organic nanoparticles doped with non-fluorescent, near-IR croconaine dye. SMS is a quantitative imaging technique that yields the absolute extinction cross-section of the nanoparticles, which can be used to determine the number of dye molecules per particle. SMS images were recorded for particles within EMT-6 breast cancer cells. The measurements allowed mapping of the nanoparticle location and the amount of dye in a single cell. The results demonstrate how SMS can facilitate efforts to optimize dye-doped nanoparticles for effective photothermal therapy of cancer.Imaging of non-fluorescent nanoparticles in complex biological environments, such as the cell cytosol, is a challenging problem. For metal nanoparticles, Rayleigh scattering methods can be used, but for organic nanoparticles, such as dye-doped polymer beads or lipid nanoparticles, light scattering does not provide good contrast. In this paper, spatial modulation spectroscopy (SMS) is used to image single organic nanoparticles doped with non-fluorescent, near-IR croconaine dye. SMS is a quantitative imaging technique that yields the absolute extinction cross-section of the nanoparticles, which can be used to determine the number of dye molecules per particle. SMS images were recorded for particles within EMT-6 breast cancer cells. The measurements allowed mapping of the nanoparticle location and the amount of dye in a single cell. The results demonstrate how SMS can facilitate efforts to optimize dye-doped nanoparticles for effective photothermal therapy of cancer. Electronic supplementary information (ESI) available: TEM imaging, calibration experiments for the SMS instrument with gold nanoparticles, SMS images of dye doped polymer beads from a commercial source, evidence for endosome uptake, and additional SMS images of dye-doped LPNPs in EMT-6 cells, and spectra of SRfluor680/croconaine doped lipid-polymer nanoparticles. See DOI: 10.1039/C5NR01614B

  9. Highly-accelerated quantitative 2D and 3D localized spectroscopy with linear algebraic modeling (SLAM) and sensitivity encoding

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Gabr, Refaat E.; Zhou, Jinyuan; Weiss, Robert G.; Bottomley, Paul A.

    2013-12-01

    Noninvasive magnetic resonance spectroscopy (MRS) with chemical shift imaging (CSI) provides valuable metabolic information for research and clinical studies, but is often limited by long scan times. Recently, spectroscopy with linear algebraic modeling (SLAM) was shown to provide compartment-averaged spectra resolved in one spatial dimension with many-fold reductions in scan-time. This was achieved using a small subset of the CSI phase-encoding steps from central image k-space that maximized the signal-to-noise ratio. Here, SLAM is extended to two- and three-dimensions (2D, 3D). In addition, SLAM is combined with sensitivity-encoded (SENSE) parallel imaging techniques, enabling the replacement of even more CSI phase-encoding steps to further accelerate scan-speed. A modified SLAM reconstruction algorithm is introduced that significantly reduces the effects of signal nonuniformity within compartments. Finally, main-field inhomogeneity corrections are provided, analogous to CSI. These methods are all tested on brain proton MRS data from a total of 24 patients with brain tumors, and in a human cardiac phosphorus 3D SLAM study at 3T. Acceleration factors of up to 120-fold versus CSI are demonstrated, including speed-up factors of 5-fold relative to already-accelerated SENSE CSI. Brain metabolites are quantified in SLAM and SENSE SLAM spectra and found to be indistinguishable from CSI measures from the same compartments. The modified reconstruction algorithm demonstrated immunity to maladjusted segmentation and errors from signal heterogeneity in brain data. In conclusion, SLAM demonstrates the potential to supplant CSI in studies requiring compartment-average spectra or large volume coverage, by dramatically reducing scan-time while providing essentially the same quantitative results.

  10. Highly-accelerated quantitative 2D and 3D localized spectroscopy with linear algebraic modeling (SLAM) and sensitivity encoding

    PubMed Central

    Zhang, Yi; Gabr, Refaat E.; Zhou, Jinyuan; Weiss, Robert G.; Bottomley, Paul A.

    2013-01-01

    Noninvasive magnetic resonance spectroscopy (MRS) with chemical shift imaging (CSI) provides valuable metabolic information for research and clinical studies, but is often limited by long scan times. Recently, spectroscopy with linear algebraic modeling (SLAM) was shown to provide compartment-averaged spectra resolved in one spatial dimension with many-fold reductions in scan-time. This was achieved using a small subset of the CSI phase-encoding steps from central image k-space that maximized the signal-to-noise ratio. Here, SLAM is extended to two- and three-dimensions (2D, 3D). In addition, SLAM is combined with sensitivity-encoded (SENSE) parallel imaging techniques, enabling the replacement of even more CSI phase-encoding steps to further accelerate scan-speed. A modified SLAM reconstruction algorithm is introduced that significantly reduces the effects of signal nonuniformity within compartments. Finally, main-field inhomogeneity corrections are provided, analogous to CSI. These methods are all tested on brain proton MRS data from a total of 24 patients with brain tumors, and in a human cardiac phosphorus 3D SLAM study at 3T. Acceleration factors of up to 120-fold versus CSI are demonstrated, including speed-up factors of 5-fold relative to already-accelerated SENSE CSI. Brain metabolites are quantified in SLAM and SENSE SLAM spectra and found to be indistinguishable from CSI measures from the same compartments. The modified reconstruction algorithm demonstrated immunity to maladjusted segmentation and errors from signal heterogeneity in brain data. In conclusion, SLAM demonstrates the potential to supplant CSI in studies requiring compartment-average spectra or large volume coverage, by dramatically reducing scan-time while providing essentially the same quantitative results. PMID:24188921

  11. Time-integrated laser-induced plasma spectroscopy in the vacuum ultraviolet for the quantitative elemental characterization of steel alloys

    NASA Astrophysics Data System (ADS)

    Khater, M. A.; van Kampen, P.; Costello, J. T.; Mosnier, J.-P.; Kennedy, E. T.

    2000-09-01

    This paper demonstrates that time-integrated space-resolved laser-induced plasma spectroscopy (TISR-LIPS) is a useful technique in the vacuum ultraviolet (VUV) for the quantitative determination of the carbon content in steels. The standard reference samples used were carbon-iron alloys containing a relatively wide concentration range of carbon (0.041-1.32%). In the experiments the output of a Q-switched Nd:YAG (1064 nm) laser, with approximately a 1 J maximum output pulse energy and approximately a 12 ns temporal pulse width, was focused onto the surface of each sample (under vacuum) in order to produce the emitting plasma. A fore-slit mounted in the target chamber allowed spatially-resolved spectral measurements in the axial direction of the plasma and provided emission lines that were almost free of the background continuum. A 1 m normal incidence vacuum spectrometer, equipped with a 1200 grooves mm-1 concave grating and a micro-channel plate/photodiode array detector combination, was used as the detection system. A particularly interesting feature of this work is the demonstration that VUV spectroscopy allows ionic lines to be used and linear calibration curves were obtained for the five carbon spectral lines (from C+ and C2+) under investigation. The limits of detection for all lines were determined; the lowest detection limit (87+/-10 ppm) was obtained from the C2+ 97.70 nm line, which compares favourably with the only available value in the literature of 100 ppm.

  12. Quantitative analysis of WC stars: constraints on neon abundances from ISO-SWS spectroscopy

    NASA Astrophysics Data System (ADS)

    Dessart, Luc; Crowther, Paul A.; Hillier, D. John; Willis, Allan J.; Morris, Patrick W.; van der Hucht, Karel A.

    2000-06-01

    Neon abundances are derived in four Galactic WC stars - ?2Vel (WR11, WC8+O7.5III), HD156385 (WR90, WC7), HD192103 (WR135, WC8) and WR146 (WC5+O8) - using mid-infrared fine-structure lines obtained with ISO-SWS. Stellar parameters for each star are derived using the non-local thermodynamic equilibrium model atmospheric code of Hillier & Miller, together with ultraviolet (IUE), optical (INT, AAT) and infrared (UKIRT, ISO) spectroscopy. In the case of ?2Vel, we adopt very recent results from De Marco et al., who followed an identical approach. ISO-SWS data sets reveal the [Neiii] 15.5-?m line in each of our targets, while [Neii] 12.8?m, [Siv] 10.5?m and [Siii] 18.7?m are observed solely in ?2Vel. Using a method updated from Barlow et al. to account for clumped winds, we derive Ne/He=(3-4)×10-3 by number, plus S/He=6×10-5 for ?2Vel. Neon is highly enriched, such that Ne/S in ?2Vel is eight times higher than cosmic values. However, observed Ne/He ratios are a factor of 2 lower than predictions of current evolutionary models of massive stars. An imprecise mass loss and distance were responsible for the much greater discrepancy in neon content identified by Barlow et al. Our sample of WC5-8 stars span a narrow range in T* (=55-71kK), with no trend towards higher temperature at earlier spectral type, supporting earlier results for a larger sample by Koesterke & Hamann. Stellar luminosities range from 100000 to 500000Lsolar, while 10-5.1 <= M/(Msolar yr-1) <= 10-4.5, adopting clumped winds, in which volume filling factors are 10per cent. In all cases, wind performance numbers are less than 10, significantly lower than recent estimates. Carbon abundances span 0.08<=C/He<=0.25 by number, while oxygen abundances remain poorly constrained.

  13. Quantitative Antimony Speciation in Shooting-Range Soils by EXAFS Spectroscopy

    SciTech Connect

    Scheinost,A.; Rossberg, A.; Vantelon, D.; Xifra, I.; Kretzschmar, R.; Leuz, A.; Funke, H.; Johnson, C.

    2006-01-01

    The Sb speciation in soil samples from Swiss shooting ranges was determined using Sb K-edge X-ray absorption spectroscopy (XAS) and advanced statistical data analysis methods (iterative transformation factor analysis, ITFA). The XAS analysis was supported by a spectral data set of 13 Sb minerals and 4 sorption complexes. In spite of a high variability in geology, soil pH (3.1-7.5), Sb concentrations (1000-17,000 mg/kg) and shooting-range history, only two Sb species were identified. In the first species, Sb is surrounded solely by other Sb atoms at radial distances of 2.90, 3.35, 4.30 and 4.51 Angstroms, indicative of metallic Sb(0). While part of this Sb(0) may be hosted by unweathered bullet fragments consisting of PbSb alloy, Pb L{sub III}-edge XAS of the soil with the highest fraction (0.75) of Sb(0) showed no metallic Pb, but only Pb{sup 2+} bound to soil organic matter. This suggests a preferential oxidation of Pb in the alloy, driven by the higher standard reduction potential of Sb. In the second species, Sb is coordinated to 6 O-atoms at a distance of 1.98 Angstroms, indicative of Sb(V). This oxidation state is further supported by an edge energy of 30,496-30,497 eV for the soil samples with <10% Sb(0). Iron atoms at radial distances of 3.10 and 3.56 Angstroms from Sb atoms are in line with edge-sharing and bidentate corner-sharing linkages between Sb(O,OH)6 and Fe(O,OH)6 octahedra. While similar structural units exist in tripuhyite, the absence of Sb neighbors contradicts formation of this Fe antimonate. Hence the second species most likely consists of inner-sphere sorption complexes on Fe oxides, with edge and corner-sharing configuration occurring simultaneously. This pentavalent Sb species was present in all samples, suggesting that it is the prevailing species after weathering of metallic Sb(0) in oxic soils. No indication of Sb(III) was found.

  14. Stand-off Raman spectroscopy: a powerful technique for qualitative and quantitative analysis of inorganic and organic compounds including explosives.

    PubMed

    Zachhuber, Bernhard; Ramer, Georg; Hobro, Alison; Chrysostom, Engelene T H; Lendl, Bernhard

    2011-06-01

    A pulsed stand-off Raman system has been built and optimised for the qualitative and quantitative analysis of inorganic and organic samples including explosives. The system consists of a frequency doubled Q-switched Nd:YAG laser (532 nm, 10 Hz, 4.4 ns pulse length), aligned coaxially with a 6? Schmidt-Cassegrain telescope for the collection of Raman scattered light. The telescope was coupled via a fibre optic bundle to an Acton standard series SP-2750 spectrograph with a PI-MAX 1024RB intensified CCD camera equipped with a 500-ps gating option for detection. Gating proved to be essential for achieving high signal-to-noise ratios in the recorded stand-off Raman spectra. In some cases, gating also allowed suppression of disturbing fluorescence signals. For the first time, quantitative analysis of stand-off Raman spectra was performed using both univariate and multivariate methods of data analysis. To correct for possible variation in instrumental parameters, the nitrogen band of ambient air was used as an internal standard. For the univariate method, stand-off Raman spectra obtained at a distance of 9 m on sodium chloride pellets containing varying amounts of ammonium nitrate (0-100%) were used. For the multivariate quantification of ternary xylene mixtures (0-100%), stand-off spectra at a distance of 5 m were used. The univariate calibration of ammonium nitrate yielded R (2) values of 0.992, and the multivariate quantitative analysis yielded root mean square errors of prediction of 2.26%, 1.97% and 1.07% for o-, m- and p-xylene, respectively. Stand-off Raman spectra obtained at a distance of 10 m yielded a detection limit of 174 ?g for NaClO(3). Furthermore, to assess the applicability of stand-off Raman spectroscopy for explosives detection in "real-world" scenarios, their detection on different background materials (nylon, polyethylene and part of a car body) and in the presence of interferents (motor oil, fuel oil and soap) at a distance of 20 m was also investigated. PMID:21336938

  15. A method for quantitative mapping of thick oil spills using imaging spectroscopy

    USGS Publications Warehouse

    Clark, Roger N.; Swayze, Gregg A.; Leifer, Ira; Livo, K. Eric; Kokaly, Raymond F.; Hoefen, Todd; Lundeen, Sarah; Eastwood, Michael; Green, Robert O.; Pearson, Neil; Sarture, Charles; McCubbin, Ian; Roberts, Dar; Bradley, Eliza; Steele, Denis; Ryan, Thomas; Dominguez, Roseanne; The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) Team

    2010-01-01

    In response to the Deepwater Horizon oil spill in the Gulf of Mexico, a method of near-infrared imaging spectroscopic analysis was developed to map the locations of thick oil floating on water. Specifically, this method can be used to derive, in each image pixel, the oil-to-water ratio in oil emulsions, the sub-pixel areal fraction, and its thicknesses and volume within the limits of light penetration into the oil (up to a few millimeters). The method uses the shape of near-infrared (NIR) absorption features and the variations in the spectral continuum due to organic compounds found in oil to identify different oil chemistries, including its weathering state and thickness. The method is insensitive to complicating conditions such as moderate aerosol scattering and reflectance level changes from other conditions, including moderate sun glint. Data for this analysis were collected by the NASA Airborne Visual Infrared Imaging Spectrometer (AVIRIS) instrument, which was flown over the oil spill on May 17, 2010. Because of the large extent of the spill, AVIRIS flight lines could cover only a portion of the spill on this relatively calm, nearly cloud-free day. Derived lower limits for oil volumes within the top few millimeters of the ocean surface directly probed with the near-infrared light detected in the AVIRIS scenes were 19,000 (conservative assumptions) to 34,000 (aggressive assumptions) barrels of oil. AVIRIS covered about 30 percent of the core spill area, which consisted of emulsion plumes and oil sheens. Areas of oil sheen but lacking oil emulsion plumes outside of the core spill were not evaluated for oil volume in this study. If the core spill areas not covered by flight lines contained similar amounts of oil and oil-water emulsions, then extrapolation to the entire core spill area defined by a MODIS (Terra) image collected on the same day indicates a minimum of 66,000 to 120,000 barrels of oil was floating on the surface. These estimates are preliminary and subject to revision pending further analysis. Based on laboratory measurements, near-infrared (NIR) photons penetrate only a few millimeters into oil-water emulsions. As such, the oil volumes derived with this method are lower limits. Further, the detection is only of thick surface oil and does not include sheens, underwater oil, or oil that had already washed onto beaches and wetlands, oil that had been burned or evaporated as of May 17. Because NIR light penetration within emulsions is limited, and having made field observations that oil emulsions sometimes exceeded 20 millimeters in thickness, we estimate that the volume of oil, including oil thicker than can be probed in the AVIRIS imagery, is possibly as high as 150,000 barrels in the AVIRIS scenes. When this value is projected to the entire spill, it gives a volume of about 500,000 barrels for thick oil remaining on the sea surface as of May 17. AVIRIS data cannot be used to confirm this higher volume, and additional field work including more in-situ measurements of oil thickness would be required to confirm this higher oil volume. Both the directly detected minimum range of oil volume, and the higher possible volume projection for oil thicker than can be probed with NIR spectroscopy imply a significantly higher total volume of oil relative to that implied by the early NOAA (National Oceanic and Atmospheric Administration) estimate of 5,000 barrels per day reported on their Web site.

  16. Syntheses, crystal structures and UV-visible absorption properties of five metal-organic frameworks constructed from terphenyl-2,5,2',5'-tetracarboxylic acid and bis(imidazole) bridging ligands.

    PubMed

    Fan, Liming; Zhang, Xiutang; Zhang, Wei; Ding, Yuanshuai; Fan, Weiliu; Sun, Liming; Pang, Yue; Zhao, Xian

    2014-05-14

    The solvothermal reactions of terphenyl-2,5,2',5'-tetracarboxylic acid (H4tptc) and transition metal cations (Ni(II), Mn(II)) afford five novel coordination polymers (CPs) in the presence of four bis(imidazole) bridging ligands (1,3-bimb = 1,3-bis(imidazol-1-ylmethyl)benzene, 1,4-bmib = 1,4-bis(2-methylimidazol-1-ylmethyl)benzene, 4,4'-bibp = 4,4'-bis(imidazol-1-yl)biphenyl, 4,4'-bimbp = 4,4'-bis(imidazol-1-ylmethyl)biphenyl), namely, [M(tptc)(0.5)(1,3-bimb)(H2O)]n (M = Ni for 1, Mn for 2), {[Ni(tptc)(0.5)(1,4-bmib)]·0.25H2O}n (3), {[Ni(tptc)(0.5)(4,4'-bibp)2(H2O)]·2H2O}n (4) and {[Ni(tptc)(0.5)(4,4'-bimbp)(1.5)(H2O)]·H2O}n (5). Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analyses. Complexes 1 and 2 are isomorphous and exhibit a 3D (3,4)-connected tfi framework with the point Schläfli symbol of (4·6(2))(4·6(6)·8(3)). Complex 3 shows an unprecedented 3D (4,4)-connected framework with the point Schläfli symbol of (4·6(4)·8(2))2(4(2)·8(4)). Complex 4 displays a novel 2D self-catenating 5-connected network with the Schläfli symbol of (4(6)·6(4)) based on three interpenetrating 4(4)-sql subnets. Complex 5 features a 2D 3-connected 6(3)-hcb network built from interesting chains with loops. To the best of our knowledge, the 3D (4,4)-connected (4·6(4)·8(2))2(4(2)·8(4)) host-framework of 3 and 2D self-catenating 5-connected (4(6)·6(4)) network of 4 have never been documented to date. Moreover, the UV-Visible absorption spectra of complexes 1-5 have been investigated. PMID:24638083

  17. Studying Flow Close to an Interface by Total Internal Reflection Fluorescence Cross Correlation Spectroscopy: Quantitative Data Analysis

    E-print Network

    R. Schmitz; S. Yordanov; H. J. Butt; K. Koynov; B. Duenweg

    2011-11-13

    Total Internal Reflection Fluorescence Cross Correlation Spectroscopy (TIR-FCCS) has recently (S. Yordanov et al., Optics Express 17, 21149 (2009)) been established as an experimental method to probe hydrodynamic flows near surfaces, on length scales of tens of nanometers. Its main advantage is that fluorescence only occurs for tracer particles close to the surface, thus resulting in high sensitivity. However, the measured correlation functions only provide rather indirect information about the flow parameters of interest, such as the shear rate and the slip length. In the present paper, we show how to combine detailed and fairly realistic theoretical modeling of the phenomena by Brownian Dynamics simulations with accurate measurements of the correlation functions, in order to establish a quantitative method to retrieve the flow properties from the experiments. Firstly, Brownian Dynamics is used to sample highly accurate correlation functions for a fixed set of model parameters. Secondly, these parameters are varied systematically by means of an importance-sampling Monte Carlo procedure in order to fit the experiments. This provides the optimum parameter values together with their statistical error bars. The approach is well suited for massively parallel computers, which allows us to do the data analysis within moderate computing times. The method is applied to flow near a hydrophilic surface, where the slip length is observed to be smaller than 10nm, and, within the limitations of the experiments and the model, indistinguishable from zero.

  18. Remote Quantitative Analysis of Minerals Based on Multispectral Line-Calibrated Laser-Induced Breakdown Spectroscopy (LIBS).

    PubMed

    2014-10-01

    Laser-induced breakdown spectroscopy (LIBS) is a feasible remote sensing technique used for mineral analysis in some unapproachable places where in situ probing is needed, such as analysis of radioactive elements in a nuclear leak or the detection of elemental compositions and contents of minerals on planetary and lunar surfaces. Here a compact custom 15 m focus optical component, combining a six times beam expander with a telescope, has been built, with which the laser beam of a 1064 nm neodymium-doped yttrium aluminum garnet (Nd:YAG) laser is focused on remote minerals. The excited LIBS signals that reveal the elemental compositions of minerals are collected by another compact single lens?based signal acquisition system. In our remote LIBS investigations, the LIBS spectra of an unknown ore have been detected, from which the metal compositions are obtained. In addition, a multi-spectral line calibration (MSLC) method is proposed for the quantitative analysis of elements. The feasibility of the MSLC and its superiority over a single-wavelength determination have been confirmed by comparison with traditional chemical analysis of the copper content in the ore. PMID:25198122

  19. Simple quantitative analysis of Escherichia coli K-12 internalized in baby spinach using Fourier Transform Infrared spectroscopy.

    PubMed

    Wang, Jun; Kim, Kyung Ho; Kim, Sungkyun; Kim, Yong Soo; Li, Qing X; Jun, Soojin

    2010-11-15

    Bacterial contamination continues to be a serious concern for food safety. Although washing fresh produce helps in reducing pathogen levels, pathogen internalization often limits the effectiveness of washing. When pathogens internalize in leafy vegetables, the method of identification and quantitative measurement would be called into question. This study was aimed to use Fourier Transform Infrared (FTIR) spectroscopy integrated with an attenuated total reflectance kit for quantification of Escherichia coli K-12 internalized in baby spinach. The bacteria were inoculated into vascular and intracellar tissues of spinach leaves by syringe injection and the distribution of internalized E. coli K-12 cells was confirmed under scanning electron microscopy (SEM). FTIR measurement following the preparation of bacterial suspension from spinach leaves with high speed pulverizing enabled to detect the absorbance peaks in the amide II region between 1590 and 1490 cm?¹ as a fingerprint for the microbes. It was found that the estimated concentrations of E. coli K-12 agreed well with the concentrations determined by plate counting with R² values of 0.98 and 0.97 in peptone water and spinach extracts, respectively. The results demonstrated that FTIR can identify and quantify E. coli K-12 in baby spinach extracts at a limit of detection of approximately 100 CFU/mL in 5 min. The developed method is expected to be suitable for the analysis of pathogenic E. coli strains and other bacterial species in fresh vegetables. PMID:20937537

  20. Quantitation of normal metabolite concentrations in six brain regions by in-vivo 1H-MR spectroscopy

    PubMed Central

    Minati, Ludovico; Aquino, Domenico; Bruzzone, Maria Grazia; Erbetta, Alessandra

    2010-01-01

    This study examined the concentrations of brain metabolites visible to in-vivo 1H-Magnetic Resonance Spectroscopy (1H-MRS) at 1.5 T in a sample of 28 normal subjects. Quantitation was attempted for inositol compounds, choline units, total creatine and N-acetyl moieties, using open-source software. Six brain regions were considered: frontal and parietal white matter, medial temporal lobe, thalamus, pons and cerebellum. Absolute concentrations were derived using tissue water as an internal reference and using an external reference; metabolite signal intensity ratios with respect to creatine were also calculated. The inter-individual variability was smaller for absolute concentrations (internal reference) as compared to that for signal intensity ratios. Significant regional variability in concentration was found for all metabolites, indicating that separate normative values are needed for different brain regions. The values obtained in this study can be used as reference in future studies, provided the same methodology is followed; it is confirmed that despite unsuccessful attempts in the past, smaller coefficients of variation can indeed be obtained through absolute quantification. PMID:20927223

  1. Java-based graphical user interface for MRUI, a software package for quantitation of in vivo\\/medical magnetic resonance spectroscopy signals

    Microsoft Academic Search

    A. Naressi; C. Couturier; I. Castang; R. de Beer; D. Graveron-Demilly

    2001-01-01

    This article describes a Java-based graphical user interface for the magnetic resonance user interface (MRUI) quantitation package. This package allows MR spectroscopists to easily perform time-domain analysis of in vivo\\/medical MR spectroscopy data. We have found that the Java programming language is very well suited for developing highly interactive graphical software applications such as the MRUI system. We also have

  2. Quantitative analysis in gas chromatography\\/low power atmospheric-pressure helium microwave-induced plasma atomic emission interferometry and ion cyclotron resonance mass spectroscopy

    Microsoft Academic Search

    Loo

    1990-01-01

    The development of experimental and data analysis techniques for quantitative analysis in gas chromatography\\/low power atmospheric pressure helium microwave-induced plasma atomic emission interferometry (GC\\/HeMIPAEI) and ion cyclotron resonance mass spectroscopy (ICR\\/MS) is presented. A discussion of interferometric data analysis by discrete and fast Fourier transform (DFT and FFT, respectively) is given. Additionally, the use of two techniques (the maximum entropy

  3. Identification and quantitation of 3,4-methylenedioxy- N-methylamphetamine (MDMA, ecstasy) in human urine by 1H NMR spectroscopy. Application to five cases of intoxication

    Microsoft Academic Search

    Jonathan Liu; John Decatur; Gloria Proni; Elise Champeil

    2010-01-01

    Identification of 3,4-methylenedioxy-N-methylamphetamine (MDMA, ecstasy) in five cases of intoxication using nuclear magnetic resonance (NMR) spectroscopy of human urine is reported. A new water suppression technique PURGE (Presaturation Utilizing Relaxation Gradients and Echoes) was used. A calibration curve was obtained using spiked samples. The method gave a linear response (correlation coefficient of 0.992) over the range 0.01–1mg\\/mL. Subsequently, quantitation of

  4. Rapid and quantitative detection of the microbial spoilage of meat by fourier transform infrared spectroscopy and machine learning.

    PubMed

    Ellis, David I; Broadhurst, David; Kell, Douglas B; Rowland, Jem J; Goodacre, Royston

    2002-06-01

    Fourier transform infrared (FT-IR) spectroscopy is a rapid, noninvasive technique with considerable potential for application in the food and related industries. We show here that this technique can be used directly on the surface of food to produce biochemically interpretable "fingerprints." Spoilage in meat is the result of decomposition and the formation of metabolites caused by the growth and enzymatic activity of microorganisms. FT-IR was exploited to measure biochemical changes within the meat substrate, enhancing and accelerating the detection of microbial spoilage. Chicken breasts were purchased from a national retailer, comminuted for 10 s, and left to spoil at room temperature for 24 h. Every hour, FT-IR measurements were taken directly from the meat surface using attenuated total reflectance, and the total viable counts were obtained by classical plating methods. Quantitative interpretation of FT-IR spectra was possible using partial least-squares regression and allowed accurate estimates of bacterial loads to be calculated directly from the meat surface in 60 s. Genetic programming was used to derive rules showing that at levels of 10(7) bacteria.g(-1) the main biochemical indicator of spoilage was the onset of proteolysis. Thus, using FT-IR we were able to acquire a metabolic snapshot and quantify, noninvasively, the microbial loads of food samples accurately and rapidly in 60 s, directly from the sample surface. We believe this approach will aid in the Hazard Analysis Critical Control Point process for the assessment of the microbiological safety of food at the production, processing, manufacturing, packaging, and storage levels. PMID:12039738

  5. Developments in laser-induced fluorescence spectroscopy for quantitative in situ measurements of free radicals in the troposphere

    NASA Astrophysics Data System (ADS)

    Heard, Dwayne

    2015-04-01

    Photo-oxidation in the troposphere is highly complex, being initiated by short lived free radical species, in the daytime dominated by the hydroxyl radical, OH. Chemical oxidation cycles, which also involve peroxy radicals (HO2 and RO2), remove natural or anthropogenic emissions (for example methane) and generate a range of secondary products, for example ozone, nitrogen dioxide, acidic and multifunctional organic species, and secondary organic aerosol, which impact on human health and climate. Owing to their short lifetime in the atmosphere, the abundance of radicals is determined solely by their rate of chemical production and loss, and not by transport. Field measurements of the concentrations of radicals and comparison with calculations using a numerical model therefore constitutes one of the very best ways to test whether the chemistry in each of these locations is understood and accurately represented in the model. Validation of the chemistry is important, as the predictions of climate and air quality models containing this chemistry are used to drive the formulation of policy and legislation. However, in situ measurements of radical species, owing to their very low abundance (often sub part per trillion) and short lifetimes (< 1 second for OH), remain extremely challenging. Laser-induced fluorescence spectroscopy (LIF) has enjoyed considerable success worldwide for the quantitative detection of radicals in a range of environments. The radicals are either excited directly by the laser (e.g. OH, IO) or are first chemically converted to OH prior to detection (e.g. HO2, RO2). Recent developments in the LIF technique for radical detection, which uses a supersonic expansion with detection at low pressure and multi kHz pulse repetition rate tunable laser systems, will be discussed, together with calibration methods to make signals absolute, and identification of potential interferences. LIF instruments have been operated on ground, ship and aircraft platforms at a number of locations worldwide, and examples from recent fieldwork involving the Leeds instruments will be presented.

  6. Rapid and Quantitative Detection of the Microbial Spoilage of Meat by Fourier Transform Infrared Spectroscopy and Machine Learning

    PubMed Central

    Ellis, David I.; Broadhurst, David; Kell, Douglas B.; Rowland, Jem J.; Goodacre, Royston

    2002-01-01

    Fourier transform infrared (FT-IR) spectroscopy is a rapid, noninvasive technique with considerable potential for application in the food and related industries. We show here that this technique can be used directly on the surface of food to produce biochemically interpretable “fingerprints.” Spoilage in meat is the result of decomposition and the formation of metabolites caused by the growth and enzymatic activity of microorganisms. FT-IR was exploited to measure biochemical changes within the meat substrate, enhancing and accelerating the detection of microbial spoilage. Chicken breasts were purchased from a national retailer, comminuted for 10 s, and left to spoil at room temperature for 24 h. Every hour, FT-IR measurements were taken directly from the meat surface using attenuated total reflectance, and the total viable counts were obtained by classical plating methods. Quantitative interpretation of FT-IR spectra was possible using partial least-squares regression and allowed accurate estimates of bacterial loads to be calculated directly from the meat surface in 60 s. Genetic programming was used to derive rules showing that at levels of 107 bacteria·g?1 the main biochemical indicator of spoilage was the onset of proteolysis. Thus, using FT-IR we were able to acquire a metabolic snapshot and quantify, noninvasively, the microbial loads of food samples accurately and rapidly in 60 s, directly from the sample surface. We believe this approach will aid in the Hazard Analysis Critical Control Point process for the assessment of the microbiological safety of food at the production, processing, manufacturing, packaging, and storage levels. PMID:12039738

  7. Spectroscopy

    NSDL National Science Digital Library

    This site describes the theory and practice of IR and NMR spectroscopy for classroom and laboratory instruction. Although it is written for a course at the University of Colorado, Boulder, this site is appropriate for anyone doing analytical measurements with infrared or NMR.

  8. Ultraviolet-Visible and Fluorescence Spectroscopy Techniques Are Important Diagnostic Tools during the Progression of Atherosclerosis: Diet Zinc Supplementation Retarded or Delayed Atherosclerosis

    PubMed Central

    Abdelhalim, Mohamed Anwar K.; Moussa, Sherif A. Abdelmottaleb; AL-Mohy, Yanallah Hussain

    2013-01-01

    Background. In this study, we examined whether UV-visible and fluorescence spectroscopy techniques detect the progression of atherosclerosis in serum of rabbits fed on high-cholesterol diet (HCD) and HCD supplemented with zinc (HCD + Zn) compared with the control. Methods. The control rabbits group was fed on 100?g/day of normal diet. The HCD group was fed on Purina Certified Rabbit Chow supplemented with 1.0% cholesterol plus 1.0% olive oil (100?g/day) for the same period. The HCD + Zn group was fed on normal Purina Certified Rabbit Chow plus 1.0% cholesterol and 1.0% olive oil supplemented with 470?ppm Zn for the same feeding period. UV-visible and fluorescence spectroscopy and biochemistry in Rabbit's blood serum and blood hematology were measured in Rabbit's blood. Results. We found that the fluorescent peak of HCD shifted toward UV-visible wavelength compared with the control using fluorescent excitation of serum at 192?nm. In addition, they showed that supplementation of zinc (350?ppm) restored the fluorescent peak closely to the control. By using UV-visible spectroscopy approach, we found that the peak absorbance of HCD (about 280?nm) was higher than that of control and that zinc supplementation seemed to decrease the absorbance. Conclusions. This study demonstrates that ultraviolet-visible and fluorescence spectroscopy techniques can be applied as noninvasive techniques on a sample blood serum for diagnosing or detecting the progression of atherosclerosis. The Zn supplementation to rabbits fed on HCD delays or retards the progression of atherosclerosis. Inducing anemia in rabbits fed on HCD delays the progression of atherosclerosis. PMID:24350281

  9. Specifications Evolution 201 UV-Visible Evolution 220 UV-Visible Spectrophotometer Spectrophotometer

    E-print Network

    Magee, Joseph W.

    -Turner Monochromator Spectral Bandwidth(s) 1.0 nm Variable: 1 nm; 2 nm; AFBG Microcell optimized; AFBG Fiber optic Spectrophotometer Optical Design Double-beam with sample and Double-beam with sample and reference cuvette positions; reference cuvette positions; Czerny-Turner Monochromator Application Focused Beam Geometry; Czerny

  10. Quantitative evaluation of the lactate signal loss and its spatial dependence in press localized (1)H NMR spectroscopy.

    PubMed

    Jung, W I; Bunse, M; Lutz, O

    2001-10-01

    Localized (1)H NMR spectroscopy using the 90 degrees -t(1)-180 degrees -t(1)+t(2)-180 degrees -t(2)-Acq. PRESS sequence can lead to a signal loss for the lactate doublet compared with signals from uncoupled nuclei which is dependent on the choice of t(1) and t(2). The most striking signal loss of up to 78% of the total signal occurs with the symmetrical PRESS sequence (t(1)=t(2)) at an echo time of 2/J (approximately 290 ms). Calculations have shown that this signal loss is related to the pulse angle distributions produced by the two refocusing pulses which leads to the creation of single quantum polarization transfer (PT) as well as to not directly observable states (NDOS) of the lactate AX(3) spin system: zero- and multiple-quantum coherences, and longitudinal spin orders. In addition, the chemical shift dependent voxel displacement (VOD) leads to further signal loss. By calculating the density operator for various of the echo times TE=n/J, n=1, 2, 3,..., we calculated quantitatively the contributions of these effects to the signal loss as well as their spatial distribution. A maximum signal loss of 75% can be expected from theory for the symmetrical PRESS sequence and TE=2/J for Hamming filtered sinc pulses, whereby 47% are due to the creation of NDOS and up to 28% arise from PT. Taking also the VOD effect into account (2 mT/m slice selection gradients, 20-mm slices) leads to 54% signal loss from NDOS and up to 24% from PT, leading to a maximum signal loss of 78%. Using RE-BURP pulses with their more rectangular pulse angle distributions reduces the maximum signal loss to 44%. Experiments at 1.5 T using a lactate solution demonstrated a maximum lactate signal loss for sinc pulses of 82% (52% NDOS, 30% PT) at TE=290 ms using the symmetrical PRESS sequence. The great signal loss and its spatial distribution is of importance for investigations using a symmetrical PRESS sequence at TE=2/J. PMID:11567573

  11. Quantitative Evaluation of the Lactate Signal Loss and Its Spatial Dependence in PRESS Localized 1H NMR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Jung, Wulf-Ingo; Bunse, Michael; Lutz, Otto

    2001-10-01

    Localized 1H NMR spectroscopy using the 90°-t1-180°-t1+t2-180°-t2-Acq. PRESS sequence can lead to a signal loss for the lactate doublet compared with signals from uncoupled nuclei which is dependent on the choice of t1 and t2. The most striking signal loss of up to 78% of the total signal occurs with the symmetrical PRESS sequence (t1=t2) at an echo time of 2/J (?290 ms). Calculations have shown that this signal loss is related to the pulse angle distributions produced by the two refocusing pulses which leads to the creation of single quantum polarization transfer (PT) as well as to not directly observable states (NDOS) of the lactate AX3 spin system: zero- and multiple-quantum coherences, and longitudinal spin orders. In addition, the chemical shift dependent voxel displacement (VOD) leads to further signal loss. By calculating the density operator for various of the echo times TE=n/J, n=1, 2, 3, …, we calculated quantitatively the contributions of these effects to the signal loss as well as their spatial distribution. A maximum signal loss of 75% can be expected from theory for the symmetrical PRESS sequence and TE=2/J for Hamming filtered sinc pulses, whereby 47% are due to the creation of NDOS and up to 28% arise from PT. Taking also the VOD effect into account (2 mT/m slice selection gradients, 20-mm slices) leads to 54% signal loss from NDOS and up to 24% from PT, leading to a maximum signal loss of 78%. Using RE-BURP pulses with their more rectangular pulse angle distributions reduces the maximum signal loss to 44%. Experiments at 1.5 T using a lactate solution demonstrated a maximum lactate signal loss for sinc pulses of 82% (52% NDOS, 30% PT) at TE=290 ms using the symmetrical PRESS sequence. The great signal loss and its spatial distribution is of importance for investigations using a symmetrical PRESS sequence at TE=2/J.

  12. Characterisation of in vivo ovarian cancer models by quantitative 1H magnetic resonance spectroscopy and diffusion-weighted imaging.

    PubMed

    Canese, Rossella; Pisanu, Maria Elena; Mezzanzanica, Delia; Ricci, Alessandro; Paris, Luisa; Bagnoli, Marina; Valeri, Barbara; Spada, Massimo; Venditti, Massimo; Cesolini, Albino; Rodomonte, Andrea; Giannini, Massimo; Canevari, Silvana; Podo, Franca; Iorio, Egidio

    2012-04-01

    Magnetic resonance imaging (MRI) and spectroscopy (MRS) offer powerful approaches for detecting physiological and metabolic alterations in malignancies and help investigate underlying molecular mechanisms. Research on epithelial ovarian carcinoma (EOC), the gynaecological malignancy with the highest death rate characterised by frequent relapse and onset of drug resistance, could benefit from application of these molecular imaging approaches. In this study, MRI/MRS were used to characterise solid tumour models obtained by subcutaneous (s.c.) or intraperitoneal (i.p.) implantation of human SKOV3.ip cells in severe combined immunodeficiency (SCID) mice. In vivo MRI/MRS, ex vivo magic-angle-spinning (MAS), and in vitro (1)H-NMR measurements were carried out at 4.7 T, 9.4 T, and 9.4/16.5 T, respectively. MRI evaluation was performed by T1-, T2-, and diffusion-weighted (DW) multislice spin-echo imaging. The in vivo (1)H spectra of all tumour models showed a prominent resonance of total choline-containing metabolites (tCho). Quantitative in vivo MRS of both i.p. and s.c. SKOV3.ip xenografts showed that the mean tCho content was in the 2.9-4.5 mM range, with a mean PCho/tCho ratio of 0.99 ± 0.01 [23 examinations, 14-34 days post injection (dpi)], in good agreement with ex vivo and in vitro analyses. Myo-inositol ranged between 11.7 and 17.0 mM, with a trend towards higher values in i.p. xenografts at 14-16 dpi. The average apparent diffusion coefficient (ADC) values of SKOV3.ip xenografts [1.64 ± 0.11 (n = 9, i.p.) and 1.58 ± 0.03 x10(-3) mm(2)/s (n = 7, s.c.)] were in agreement with values reported for tumours from patients with EOC, while the mean vascular signal fraction (VSF) was lower (? 4%), probably due to the more rapid growth of preclinical models. Both s.c. and i.p. xenografts are valuable preclinical models for monitoring biochemical and physiopathological changes associated with in vivo EOC tumour growth and response to therapy, which may serve as the basis for further clinical development of noninvasive MR approaches. PMID:22020805

  13. High-Throughput Near-Infrared Reflectance Spectroscopy for Predicting Quantitative and Qualitative Composition Phenotypes of Individual Maize Kernels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Near-infrared reflectance (NIR) spectroscopy can be used for fast and reliable prediction of organic compounds in complex biological samples. We used a recently developed NIR spectroscopy instrument to predict starch, protein, oil, and weight of individual maize (Zea mays) seeds. The starch, prote...

  14. Quantitative Determination of the Biodegradable Polymer Poly(?-hydroxybutyrate) in a Recombinant Escherichia coli Strain by Use of Mid-Infrared Spectroscopy and Multivariative Statistics

    PubMed Central

    Kansiz, Mustafa; Billman-Jacobe, Helen; McNaughton, Don

    2000-01-01

    Fourier transform infrared (FTIR) spectroscopy in combination with the partial least squares (PLS) multivariative statistical technique was used for quantitative analysis of the poly(?-hydroxybutyrate) (PHB) contents of bacterial cells. A total of 237 replicate spectra from 34 samples were obtained together with gas chromatography-determined reference PHB contents. Using the PLS regression, we were able to relate the infrared spectra to the reference PHB contents, and the correlation coefficient between the measured and predicted values for the optimal model with a standard error of prediction of 1.49% PHB was 0.988. With this technique, there are no solvent requirements, sample preparation is minimal and simple, and analysis time is greatly reduced; our results demonstrate the potential of FTIR spectroscopy as an alternative to the conventional methods used for analysis of PHB in bacterial cells. PMID:10919800

  15. Quantitation of Absorbers in Turbid Media Using Time-Integrated Spectroscopy Based on Microscopic Beer-Lambert Law

    NASA Astrophysics Data System (ADS)

    Zhang, Hedong; Miwa, Mitsuharu; Yamashita, Yutaka; Tsuchiya, Yutaka

    1998-05-01

    Based on the microscopic Beer-Lambert law, two practical time-integrated spectroscopy (TIS) methods, called dual-wavelength spectroscopy method, and dual-wavelength and dual-site spectroscopy method, are described to determine the absolute concentration of an absorber in variously shaped turbid media. We demonstrate, for the first time, the validity of the TIS methods by means of experiments in which the absolute concentrations of an absorber in a tissue-like phantom were determined with errors less than several percent. The advantages and disadvantages of both methods are also discussed.

  16. The use of low-energy ion scattering spectroscopy for the quantitative determination of adsorption sites in surface chemistry studies

    Microsoft Academic Search

    Nancy R. Gleason; Francisco Zaera

    1997-01-01

    Ion scattering spectroscopy (ISS) was used in conjunction with temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS) for the study of the adsorption of hydrogen, oxygen, ethyl iodide, and 2-propyl iodide on Ni(100). In all those systems the decrease in Ni ISS signal intensity seen during the uptake could be explained by shielding of the Ni surface atoms by the

  17. Quantitative measurement of residual biaxial stress by Raman spectroscopy in diamond grown on a Ti alloy by chemical vapor deposition

    Microsoft Academic Search

    Joel Ager; Michael Drory

    1993-01-01

    Raman spectroscopy is used to study residual stress in diamond grown on Ti--6Al--4V by chemical vapor deposition. A general model is developed to use Raman spectroscopy to measure biaxial stress in polycrystalline, diamond-structure films. The as-grown film has 7.1 GPa of residual compressive stress, consistent with the difference in thermal-expansion coefficients between the diamond film and the substrate. Examination of

  18. FT-IR TRANSMISSION SPECTROSCOPY FOR QUANTITATION OF AMMONIUM BISULFATE IN FINE PARTICULATE MATTER COLLECTED ON TEFLON FILTERS

    EPA Science Inventory

    A quantitative measurement method for fine particle bisulfatein ammonium bisulfate collected from the ambient air onto Teflon filters is described. nfrared absorbance measurements of the Teflon filters are made before and after particle collection. ubtraction of the two spectra r...

  19. Electron paramagnetic resonance spectroscopy studies of oxidative degradation of an active pharmaceutical ingredient and quantitative analysis of the organic radical intermediates using partial least-squares regression.

    PubMed

    Williams, Helen Elizabeth; Loades, Victoria Catherine; Claybourn, Mike; Murphy, Damien Martin

    2006-01-15

    Electron paramagnetic resonance (EPR) spectroscopy was used to study the radical species formed during the oxidation of an active pharmaceutical ingredient in the solid state. It was found that the extent of radical generation correlated to the formation of an oxidative degradation product. Multifrequency EPR and electron nuclear double resonance spectroscopy gave additional information on the identity of the organic radical species involved in the oxidation process, and a mechanism was proposed for the degradation, involving the formation of both carbon-centered and peroxy radicals. The multivariate analysis technique of partial least-squares (PLS) regression was then used to determine the extent of oxidation of the active pharmaceutical ingredient from the EPR spectra. The suitability of this approach was demonstrated from its application to a series of standards. The conventional approach for the quantitative analysis of EPR spectra is to measure the peak height or to perform double integration of the spectral region containing the signal of interest. Both of these methods have intrinsic errors associated with them, particularly for weak EPR signals with a poor signal-to-noise ratio or a sloping background response. The results obtained showed that greatly improved quantitation was obtained using the PLS regression approach. PMID:16408946

  20. Natural deuterium distribution in fatty acids isolated from peanut seed oil: a site-specific study by quantitative 2H NMR spectroscopy.

    PubMed

    Duan, Jia-Rong; Billault, Isabelle; Mabon, Françoise; Robins, Richard

    2002-08-01

    Quantitative (2)H NMR spectroscopy has been used to measure the distribution of deuterium at natural abundance in long-chain fatty acids extracted from the same vegetable oil. Peanut seed oil was selected, due to its suitable oleic and linoleic acid content. The methyl esters of the fatty acids were prepared by transesterification and isolated by modified argentation column chromatography on silica. In order to measure the natural isotopic fractionation of deuterium (D) at the maximum number of positions, the purified methyl oleate and methyl linoleate were chemically cleaved and the (D/H)(i) values determined by quantitative (2)H NMR spectroscopy. It was thus possible to demonstrate that fractionation in deuterium occurs during the desaturation of oleate to linoleate. Furthermore, the previously observed distribution of deuterium at the sites of desaturation is confirmed, as is the alternating pattern of (D/H)(i), which relates to the origin of the pertinent hydrogen atoms. The data obtained are discussed in terms of the kinetic isotopic effects intrinsic to the enzymes-synthetases and desaturases-involved in the biosynthesis of fatty acids. PMID:12203973

  1. I. Analysis of biological specimens by proton-induced x-ray emission spectroscopy (PIXE). II. Separation and purity of C{sub 60} and C{sub 70}

    SciTech Connect

    Lowe, T.P.

    1993-12-31

    This report outlines work done on the optimization of instrumental parameters and sample preparation for the analysis of biological tissue. The analysis of biological samples by PIXE provides information on interelemental interactions in tissue and body fluids. A computer program for spectrum processes and quantitation, which decomposes overlapped peaks, corrects for thick target matrix effects and calculates results without resorting to the use of standards, is explored. In part II of this dissertation, a convenient method of removing solvent from a benzene extract of graphite soot containing fullerenes using sublimation, is outlined. Separation of macroscopic quantities of the fullerenes C{sub 60} and C{sub 70} has been accomplished using a combination of selective precipitation of C{sub 60} and chromatography. C{sub 60} is selectively crystallized freezing and thawing a benzene solution of mixed fullerenes, then using the C{sub 70} enriched supernatant as starting material in the chromatographic separation of C{sub 60} and C{sub 70}. In the separation scheme, a bed of modified silica sorbent is charged with the fullerene mixture and the fullerenes are eluted using a hexanes/THF mobile phase. The methods of UV-Visible and infrared spectroscopy, as well as high performance liquid chromatography (HPLC) are evaluated for their ability to determine the purity of a C{sub 60} or C{sub 70} sample.

  2. Combining Raman and FT-IR spectroscopy with quantitative isotopic labeling for differentiation of E. coli cells at community and single cell levels.

    PubMed

    Muhamadali, Howbeer; Chisanga, Malama; Subaihi, Abdu; Goodacre, Royston

    2015-04-21

    There is no doubt that the contribution of microbially mediated bioprocesses toward maintenance of life on earth is vital. However, understanding these microbes in situ is currently a bottleneck, as most methods require culturing these microorganisms to suitable biomass levels so that their phenotype can be measured. The development of new culture-independent strategies such as stable isotope probing (SIP) coupled with molecular biology has been a breakthrough toward linking gene to function, while circumventing in vitro culturing. In this study, for the first time we have combined Raman spectroscopy and Fourier transform infrared (FT-IR) spectroscopy, as metabolic fingerprinting approaches, with SIP to demonstrate the quantitative labeling and differentiation of Escherichia coli cells. E. coli cells were grown in minimal medium with fixed final concentrations of carbon and nitrogen supply, but with different ratios and combinations of (13)C/(12)C glucose and (15)N/(14)N ammonium chloride, as the sole carbon and nitrogen sources, respectively. The cells were collected at stationary phase and examined by Raman and FT-IR spectroscopies. The multivariate analysis investigation of FT-IR and Raman data illustrated unique clustering patterns resulting from specific spectral shifts upon the incorporation of different isotopes, which were directly correlated with the ratio of the isotopically labeled content of the medium. Multivariate analysis results of single-cell Raman spectra followed the same trend, exhibiting a separation between E. coli cells labeled with different isotopes and multiple isotope levels of C and N. PMID:25831066

  3. Quantitation of the global secondary structure of globular proteins by FTIR spectroscopy: Comparison with X-ray crystallographic structure

    Microsoft Academic Search

    Thomas F. Kumosinski; Joseph J. Unruh

    1996-01-01

    Fourier transform infrared spectroscopy (FTIR) is potentially a powerful tool for determining the global secondary structure of proteins in solution, providing the spectra are analyzed using a statistically and theoretically justified methodology. We have performed FTIR experiments on 14 globular proteins and two synthetic polypeptides whose X-ray crystal structures are known to exhibit varying types and amounts of secondary structures.

  4. Quantitative Investigation of Compartmentalized Dynamics of ErbB2 Targeting Gold Nanorods in Live Cells by Single Molecule Spectroscopy

    Microsoft Academic Search

    Jiji Chen; Joseph Irudayaraj

    2009-01-01

    Understanding the diffusion dynamics and receptor uptake mechanism of nanoparticles in cancer cells is crucial to the rational design of multifunctional nanoprobes for targeting and delivery. In this report, for the first time, we quantify the localization and evaluate the diffusion times of Herceptin-conjugated gold nanorods (H-GNRs) in different cell organelles by fluorescence correlation spectroscopy (FCS) and examine the endocytic

  5. The ratio of the single and double scattering intensities in ion scattering spectroscopy as a quantitative measure of surface structures

    Microsoft Academic Search

    A. J. Algra; S. B. Luitjens; H. Borggreve; E. P. Th. M. Suurmeijer; A. L. Boers

    1982-01-01

    The ratio R of the intensities of the single and double scattering peaks observed in Ion Scattering Spectroscopy has been determined as a function of several experimental parameters. If all particles scattered through a certain scattering angle are detected with a time of flight spectrometer or when alkali ions are used as primary particles then the absolute value of R

  6. Detection and Quantitative Analysis of Chemical Species in Hanford Tank Materials Using Raman Spectroscopy Technology: FY94Florida State University Raman Spectroscopy Report

    SciTech Connect

    Reich, F.R.

    1997-08-11

    This report provides a summary of work completed in FY-94 by FSU to develop and investigate the feasibility of using Raman spectroscopy with Hanford tank waste materials. Raman performance impacts from sample morphology, including the effects of absorption, particle size, density, color and refractive index, are discussed. An algorithm for relative species concentration measurement from Raman data is presented. An Algorithm for applying Raman to tank waste core screening is presented and discussed. A library of absorption and Raman spectra are presented that support this work.

  7. Quantitative Analysis of Simulated Illicit Street-Drug Samples Using Raman Spectroscopy and Partial Least Squares Regression

    Microsoft Academic Search

    Owen S. Fenton; Lindsey A. Tonge; Taylor H. Moot; Kimberley A. Frederick

    2011-01-01

    Modern drug laws require that a seized sample be characterized for both the illegal substances present and the quantity of each of those substances. The goal of this work was to develop a common approach to model development based on Raman spectroscopic analysis followed by partial least squares (PLS) regression that would allow us to obtain quantitative information from simulated

  8. Structural and reactivity studies on 4,4 ?-dimethyl-2,2 ?-bipyridine acetylacetonate copper(II) nitrate (CASIOPEINA III-ia ®) with methionine, by UV–visible and EPR techniques

    Microsoft Academic Search

    Araceli Tovar-Tovar; Lena Ruiz-Ram??rez; Antonio Campero; Antonio Romerosa; Rafael Moreno-Esparza; Maria J. Rosales-Hoz

    2004-01-01

    When the nitrate form of [(4,4?-dimethyl-2,2?-bipyridine)(acetylacetonate) copper(II)] nitrate (Casiope??na III ia) was reacted with methionine under two different reaction conditions: room temperature and reflux in methanol, it was found that substitution of acetylacetonate (acac) occurred and this process was monitored by UV–Vis spectrophotometry. Electron paramagnetic resonance (EPR) spectroscopy was used to analyse changes in the electronic environment of Cu(II) in

  9. Quantitative determination of cyfluthrin in n-hexane by terahertz time-domain spectroscopy with chemometrics methods

    Microsoft Academic Search

    Yuefang Hua; Hongjian Zhang; Hongliang Zhou

    2009-01-01

    Terahertz time-domain spectroscopy (THz-TDS) was used for the detection of cyfluthrin content in N-hexane solvent with the concentration range of 0.5-10 mug\\/mL. The absorbance of the solution form cyfluthrin was obtained in the frequency range between 0.5-1.5 THz. Two kinds of multivariate linear regression models were then built between the absorbance and the concentration of 15 samples, using partial least

  10. Quantitative Evaluation of the Lactate Signal Loss and Its Spatial Dependence in PRESS Localized 1H NMR Spectroscopy

    Microsoft Academic Search

    Wulf-Ingo Jung; Michael Bunse; Otto Lutz

    2001-01-01

    Localized 1H NMR spectroscopy using the 90°?t1?180°?t1+t2?180°?t2?Acq. PRESS sequence can lead to a signal loss for the lactate doublet compared with signals from uncoupled nuclei which is dependent on the choice of t1 and t2. The most striking signal loss of up to 78% of the total signal occurs with the symmetrical PRESS sequence (t1=t2) at an echo time of

  11. High-throughput quantitative biochemical characterization of algal biomass by NIR spectroscopy; multiple linear regression and multivariate linear regression analysis.

    PubMed

    Laurens, L M L; Wolfrum, E J

    2013-12-18

    One of the challenges associated with microalgal biomass characterization and the comparison of microalgal strains and conversion processes is the rapid determination of the composition of algae. We have developed and applied a high-throughput screening technology based on near-infrared (NIR) spectroscopy for the rapid and accurate determination of algal biomass composition. We show that NIR spectroscopy can accurately predict the full composition using multivariate linear regression analysis of varying lipid, protein, and carbohydrate content of algal biomass samples from three strains. We also demonstrate a high quality of predictions of an independent validation set. A high-throughput 96-well configuration for spectroscopy gives equally good prediction relative to a ring-cup configuration, and thus, spectra can be obtained from as little as 10-20 mg of material. We found that lipids exhibit a dominant, distinct, and unique fingerprint in the NIR spectrum that allows for the use of single and multiple linear regression of respective wavelengths for the prediction of the biomass lipid content. This is not the case for carbohydrate and protein content, and thus, the use of multivariate statistical modeling approaches remains necessary. PMID:24229385

  12. Using wide-field quantitative diffuse reflectance spectroscopy in combination with high-resolution imaging for margin assessment

    NASA Astrophysics Data System (ADS)

    Kennedy, Stephanie; Mueller, Jenna; Bydlon, Torre; Brown, J. Quincy; Ramanujam, Nimmi

    2011-03-01

    Due to the large number of women diagnosed with breast cancer and the lack of intra-operative tools, breast cancer margin assessment presents a significant unmet clinical need. Diffuse reflectance spectral imaging provides a method for quantitatively interrogating margins of lumpectomy specimens. We have previously found that [?- carotene]/?s' is a diagnostically important parameter but both parameters, [?-carotene] and ?s', were derived from a low resolution parameter map and are subject to the tissue type and heterogeneity present in the breast. In this study, we used diffuse reflectance measurements from individual sites co-registered with high resolution microendoscopy (HRME) images to determine if the combined performance of these technologies could improve margin assessment. By comparing the optical parameters of [?-carotene] and ?s' to the quantitative HRME image endpoints of feature size, feature density and normalized fluorescence, we determined that adding HRME to spectral imaging can improve the specificity of our diffuse reflectance spectral imaging system.

  13. On-site quantitative elemental analysis of metal ions in aqueous solutions by underwater laser-induced breakdown spectroscopy combined with electrodeposition under controlled potential.

    PubMed

    Matsumoto, Ayumu; Tamura, Ayaka; Koda, Ryo; Fukami, Kazuhiro; Ogata, Yukio H; Nishi, Naoya; Thornton, Blair; Sakka, Tetsuo

    2015-02-01

    We propose a technique of on-site quantitative analysis of Zn(2+) in aqueous solution based on the combination of electrodeposition for preconcentration of Zn onto a Cu electrode and successive underwater laser-induced breakdown spectroscopy (underwater LIBS) of the electrode surface under electrochemically controlled potential. Zinc emission lines are observed with the present technique for a Zn(2+) concentration of 5 ppm. It is roughly estimated that the overall sensitivity over 10?000 times higher is achieved by the preconcentration. Although underwater LIBS suffers from the spectral deformation due to the dense plasma confined in water and also from serious shot-to-shot fluctuations, a linear calibration curve with a coefficient of determination R(2) of 0.974 is obtained in the range of 5-50 ppm. PMID:25560224

  14. Quantitative speciation of Mn-bearing particulates emitted from autos burning (methylcyclopentadienyl)manganese tricarbonyl-added gasolines using XANES spectroscopy

    SciTech Connect

    Ressler, T.; Wong, J.; Roos, J.; Smith, I.L.

    2000-03-15

    The chemical nature of Mn-containing particulates emitted from (methylcyclopentadienyl)manganese tricarbonyl-added gasoline engines has been elucidated using Mn K-edge X-ray absorption fine structure (XAFS) spectroscopy. Edge shift data from the X-ray absorption near-edge structure (SANES) spectra showed that the average Mn valence in these particulates is {approximately}2.2. Using a principal component analysis (PCA) algorithm, the number and type of probable species contained in these particulates were determined to be three, consisting of Mn{sub 3}O{sub 4}, MnSO{sub 4}{sm_bullet}H{sub 2}O, and a divalent manganese phosphate, Mn{sub 5}(PO{sub 4})[PO{sub 3}(OH)]{sub 2}{sm_bullet}4H{sub 2}O. The proportions of these Mn phases in each particulate sample were evaluated quantitatively using least-squares fitting (LSF) of the experimental XANES spectra with linear combinations of these principal component (model compound) spectra. Two groups of Mn-bearing particulates may be distinguished: group I having 4--9 wt % of Mn{sub 3}O{sub 4} and exhibiting a single intense first major absorption maximum at the Mn K-edge and group II containing 15--22 wt % of Mn{sub 3}O{sub 4} and exhibiting a doublet absorption maximum at lower intensity. Fourier transforms of the EXAFS signals were found to corroborate the XANES results. This study clearly establishes XANES spectroscopy, in combination with PCA and LSF, as a quantitative analytical tool for speciation of dilute and/or amorphous multicomponent environmental materials not easily attainable with conventional methods.

  15. Estimation of soil clay and organic matter using two quantitative methods (PLSR and MARS) based on reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Nawar, Said; Buddenbaum, Henning; Hill, Joachim

    2014-05-01

    A rapid and inexpensive soil analytical technique is needed for soil quality assessment and accurate mapping. This study investigated a method for improved estimation of soil clay (SC) and organic matter (OM) using reflectance spectroscopy. Seventy soil samples were collected from Sinai peninsula in Egypt to estimate the soil clay and organic matter relative to the soil spectra. Soil samples were scanned with an Analytical Spectral Devices (ASD) spectrometer (350-2500 nm). Three spectral formats were used in the calibration models derived from the spectra and the soil properties: (1) original reflectance spectra (OR), (2) first-derivative spectra smoothened using the Savitzky-Golay technique (FD-SG) and (3) continuum-removed reflectance (CR). Partial least-squares regression (PLSR) models using the CR of the 400-2500 nm spectral region resulted in R2 = 0.76 and 0.57, and RPD = 2.1 and 1.5 for estimating SC and OM, respectively, indicating better performance than that obtained using OR and SG. The multivariate adaptive regression splines (MARS) calibration model with the CR spectra resulted in an improved performance (R2 = 0.89 and 0.83, RPD = 3.1 and 2.4) for estimating SC and OM, respectively. The results show that the MARS models have a great potential for estimating SC and OM compared with PLSR models. The results obtained in this study have potential value in the field of soil spectroscopy because they can be applied directly to the mapping of soil properties using remote sensing imagery in arid environment conditions. Key Words: soil clay, organic matter, PLSR, MARS, reflectance spectroscopy.

  16. ERDA Paper: Quantitative Measurement of Chromium, Manganese, Rhenium, and Magnesium in Liquid by Laser-Induced Breakdown Spectroscopy

    SciTech Connect

    Keller, E.L.

    2000-06-27

    A technique is needed to measure Tc during the waste process at DOE Hanford site. Laser induced breakdown spectroscopy (LIBS), a laser-based, non-intrusive, and sensitive optical diagnostic technique for measuring the concentration of various atomic and molecular species in test media, has the potential to be an on-line monitor to monitor Tc in the effluent from the Tc removal column to track the technetium removal process. In this work, we evaluate the analytical figure of merit of LIBS system for the element that has similar properties to Tc.

  17. Combining FT-IR spectroscopy and multivariate analysis for qualitative and quantitative analysis of the cell wall composition changes during apples development.

    PubMed

    Szymanska-Chargot, M; Chylinska, M; Kruk, B; Zdunek, A

    2015-01-22

    The aim of this work was to quantitatively and qualitatively determine the composition of the cell wall material from apples during development by means of Fourier transform infrared (FT-IR) spectroscopy. The FT-IR region of 1500-800 cm(-1), containing characteristic bands for galacturonic acid, hemicellulose and cellulose, was examined using principal component analysis (PCA), k-means clustering and partial least squares (PLS). The samples were differentiated by development stage and cultivar using PCA and k-means clustering. PLS calibration models for galacturonic acid, hemicellulose and cellulose content from FT-IR spectra were developed and validated with the reference data. PLS models were tested using the root-mean-square errors of cross-validation for contents of galacturonic acid, hemicellulose and cellulose which was 8.30 mg/g, 4.08% and 1.74%, respectively. It was proven that FT-IR spectroscopy combined with chemometric methods has potential for fast and reliable determination of the main constituents of fruit cell walls. PMID:25439873

  18. Quantitative data on blood flow during tumor PDT obtained by laser Doppler spectroscopy in the hen's egg test system

    NASA Astrophysics Data System (ADS)

    Vervoorts, Anja; Rood, H. A.; Klotz, Marcus; Moser, Joerg G.; Rosenbruch, Martin

    1995-01-01

    Oxygen supply is the most important requirement of type II photodynamic reactions. Prerequisite in photodynamic tumor therapy is an intact tumor blood flow during irradiation. Most photosensitizers destroy tumor vessels due to accumulation in endothelial cells. As a prerequisite to develop novel photosensitizing drugs an in-vivo test system is required to quantitatively assess for inertness of those sensitizers to the blood supply. We adapted and further developed a system capable of measuring the relative oxygen supply to heterotransplanted tumors on the yolk sac membrane (YSM) of fertilized chicken eggs.

  19. Quantitative determination of the oxidation state of iron in biotite using x-ray photoelectron spectroscopy: II. In situ analyses

    SciTech Connect

    Raeburn, S.P. [Pennsylvania State Univ., University Park, PA (United States)] [Pennsylvania State Univ., University Park, PA (United States); [Lehigh Univ., Bethlehem, PA (United States); Ilton, E.S. [Lehigh Univ., Bethlehem, PA (United States)] [Lehigh Univ., Bethlehem, PA (United States); Veblen, D.R. [Johns Hopkins Univ., Baltimore, MD (United States)] [Johns Hopkins Univ., Baltimore, MD (United States)

    1997-11-01

    X-ray photoelectron spectroscopy (XPS) was used to determine Fe(III)/{Sigma}Fe in individual biotite crystals in thin sections of ten metapelites and one syenite. The in situ XPS analyses of Fe(III)/{Sigma}Fe in biotite crystals in the metapelites were compared with published Fe(III)/{Sigma}Fe values determined by Moessbauer spectroscopy (MS) for mineral separates from the same hand samples. The difference between Fe(III)/{Sigma}Fe by the two techniques was greatest for samples with the lowest Fe(III)/{Sigma}Fe (by MS). For eight metamorphic biotites with Fe(III)/{Sigma}Fe = 9-27% comparison of the two techniques yielded a linear correlation of r = 0.94 and a statistically acceptable fit of [Fe(III)/{Sigma}Fe]{sub xps} = [Fe(III)/{Sigma}Fe]{sub ms}. The difference between Fe(III)/{Sigma}Fe by the two techniques was greater for two samples with Fe(III)/{Sigma}Fe {le} 6% (by MS). For biotite in the syenite sample, Fe(III)/{Sigma}Fe determined by both in situ XPS and bulk wet chemistry/electron probe microanalysis were similar. This contribution demonstrates that XPS can be used to analyze bulk Fe(III)/{Sigma}Fe in minerals in thin sections when appropriate precautions taken to avoid oxidation of the near-surface during preparation of samples. 25 refs., 3 figs., 4 tabs.

  20. Principles, performance, and applications of spectral reconstitution (SR) in quantitative analysis of oils by Fourier transform infrared spectroscopy (FT-IR).

    PubMed

    García-González, Diego L; Sedman, Jacqueline; van de Voort, Frederik R

    2013-04-01

    Spectral reconstitution (SR) is a dilution technique developed to facilitate the rapid, automated, and quantitative analysis of viscous oil samples by Fourier transform infrared spectroscopy (FT-IR). This technique involves determining the dilution factor through measurement of an absorption band of a suitable spectral marker added to the diluent, and then spectrally removing the diluent from the sample and multiplying the resulting spectrum to compensate for the effect of dilution on the band intensities. The facsimile spectrum of the neat oil thus obtained can then be qualitatively or quantitatively analyzed for the parameter(s) of interest. The quantitative performance of the SR technique was examined with two transition-metal carbonyl complexes as spectral markers, chromium hexacarbonyl and methylcyclopentadienyl manganese tricarbonyl. The estimation of the volume fraction (VF) of the diluent in a model system, consisting of canola oil diluted to various extents with odorless mineral spirits, served as the basis for assessment of these markers. The relationship between the VF estimates and the true volume fraction (VF(t)) was found to be strongly dependent on the dilution ratio and also depended, to a lesser extent, on the spectral resolution. These dependences are attributable to the effect of changes in matrix polarity on the bandwidth of the ?(CO) marker bands. Excellent VF(t) estimates were obtained by making a polarity correction devised with a variance-spectrum-delineated correction equation. In the absence of such a correction, SR was shown to introduce only a minor and constant bias, provided that polarity differences among all the diluted samples analyzed were minimal. This bias can be built into the calibration of a quantitative FT-IR analytical method by subjecting appropriate calibration standards to the same SR procedure as the samples to be analyzed. The primary purpose of the SR technique is to simplify preparation of diluted samples such that only approximate proportions need to be adhered to, rather than using exact weights or volumes, the marker accounting for minor variations. Additional applications discussed include the use of the SR technique in extraction-based, quantitative, automated FT-IR methods for the determination of moisture, acid number, and base number in lubricating oils, as well as of moisture content in edible oils. PMID:23601545

  1. Quantitative analysis of CN/TiCN/TiN multilayers and their thermal stability by Auger electron spectroscopy and Rutherford backscattering spectrometry depth profiles

    SciTech Connect

    Prieto, P.; Morant, C.; Climent-Font, A.; Munoz, A.; Elizalde, E.; Sanz, J.M. [Departamento de Fisica Aplicada C-XII, Universidad Autonoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Departamento de Fisica Aplicada C-XII, Universidad Autonoma de Madrid, Cantoblanco, E-28049 Madrid, Spain and Centro de Micro-Analisis de Materiales, Universidad Autonoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Centro de Micro-Analisis de Materiales, Universidad Autonoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Departamento de Fisica Aplicada C-XII, Universidad Autonoma de Madrid, Cantoblanco, E-28049 Madrid (Spain)

    2006-03-15

    CN/TiCN/TiN multilayers and the respective single layers have been deposited on Si(100) substrates using a dual ion-beam sputtering system. Both the multilayers and the respective single layers have been chemically characterized by Auger electron spectroscopy (AES) depth profiling combined with factor analysis and by Rutherford backscattering spectrometry (RBS). The combination of AES and RBS allows a quantitative chemical characterization of the multilayer and the respective single layers. Whereas RBS has some difficulties to determine the in-depth distribution of the light elements along the multilayer, AES depth profiling enables their quantitative analysis and even their chemical state along the multilayer. On the contrary, RBS shows its advantages to determine the heavy elements, including the contaminants incorporated during the deposition process (e.g., W). Under special experimental conditions it is shown that RBS is able to determine the composition of the single layers (i.e., CN/Si, TiCN/Si, and TiN/Si) in good agreement with AES depth profiling. As a result of this complementary use we obtain a complete quantitative chemical characterization of the single layers and multilayers. In addition, the thermal stability of the multilayers upon heating for 1 h in vacuum and ambient atmospheres at 500 deg. C has been studied by AES depth profiling. The results show that whereas the multilayer is stable in vacuum it undergoes significant changes when it is heated in air. In fact, it is shown that annealing in air for 1 h causes the disappearance of the CN top layer and the oxidation of the TiCN layer that leads to the formation of TiO{sub 2} on its surface.

  2. Atomic emission stratigraphy by laser-induced plasma spectroscopy: Quantitative depth profiling of metal thin film systems

    NASA Astrophysics Data System (ADS)

    Nagy, Tristan O.; Pacher, Ulrich; Pöhl, Hannes; Kautek, Wolfgang

    2014-05-01

    Laser-induced plasma spectroscopy (LIPS) with a frequency-quadrupled Nd:YAG laser (266 nm, pulse duration: 4 ns) was applied to a metallic layer system consisting of an electrodeposited copper layer (30 ?m) on an aluminium substrate. A stratigraphic model describing the emission signal in dependence of the pulse number was developed, which can explain several effects originating from laser ablation of various thin top layers by means of the Gaussian beam cross section character. This model was applied to trace elements through layers with thicknesses that are in the range of the resolvable depth, given by the single-pulse ablation rate, by means of empirical fitting functions. Additionally, the contribution of redeposited bulk material to the characteristic shape of emission-traces when averaging spot arrays with varying spacing could be quantified. This can be used to estimate cross-contamination in analytical applications where ablations need to be performed at close spacing.

  3. The Araucaria Project: the Local Group Galaxy WLM--Distance and metallicity from quantitative spectroscopy of blue Supergiants

    E-print Network

    M. A. Urbaneja; R. -P. Kudritzki; F. Bresolin; N. Przybilla; W. Gieren; G. Pietrzynski

    2008-05-22

    The quantitative analysis of low resolution spectra of A and B supergiants is used to determine a distance modulus of 24.99 +/- 0.10 mag (995 +/- 46 Kpc) to the Local Group galaxy WLM. The analysis yields stellar effective temperatures and gravities, which provide a distance through the Flux weighted Gravity--Luminosity Relationship (FGLR). Our distance is 0.07 mag larger than the most recent results based on Cepheids and the tip of the RGB. This difference is within the 1-sigma overlap of the typical uncertainties quoted in these photometric investigations. In addition, non-LTE spectral synthesis of the rich metal line spectra (mostly iron, chromium and titanium) of the A supergiants is carried out, which allows the determination of stellar metallicities. An average metallicity of -0.87 +/- 0.06 dex with respect to solar metallicity is found.

  4. [Visible and near infrared spectroscopy combined with recursive variable selection to quantitatively determine soil total nitrogen and organic matter].

    PubMed

    Jia, Sheng-yao; Tang, Xu; Yang, Xiang-long; Li, Guang; Zhang, Jian-ming

    2014-08-01

    In the present work, recursive variable selection methods (updating both the model coefficients and effective variables during the prediction process) were applied to maintain the predictive abilities of calibration models. This work compared the performances of partial least squares (PLS), recursive PLS (RPLS) and three recursive variable selection methods, namely vari- able importance in the projection combined with RPLS (VIP-RPLS), VIP-PLS, and uninformative variable elimination combined with PLS (UVE-PLS) for the measurement of soil total nitrogen (TN) and organic matter (OM) using Vis-NIR spectroscopy. The dataset consisted of 195 soil samples collected from eight towns in Wencheng County, Zhejiang Province, China. The entire data set was split randomly into calibration set and prediction set. The calibration set was composed of 120 samples, while the prediction set included 75 samples. The best prediction results were obtained by the VIP-RPLS model. The coefficient of determination (R2) and residual prediction deviation (RPD) were respectively 0.85, 0.86 and 2.6%, 2.7% for soil TN and OM. The results indicate that VIP-RPLS is able to capture the effective information from the latest modeling sample by recursively updating the effective variables. The proposed method VIP-RPLS has the advantages of better performance for Vis-NIR prediction of soil N and OM compared with other methods in this work. PMID:25508715

  5. [Visible and near infrared spectroscopy combined with recursive variable selection to quantitatively determine soil total nitrogen and organic matter].

    PubMed

    Jia, Sheng-yao; Tang, Xu; Yang, Xiang-long; Li, Guang; Zhang, Jian-ming

    2014-08-01

    In the present work, recursive variable selection methods (updating both the model coefficients and effective variables during the prediction process) were applied to maintain the predictive abilities of calibration models. This work compared the performances of partial least squares (PLS), recursive PLS (RPLS) and three recursive variable selection methods, namely vari- able importance in the projection combined with RPLS (VIP-RPLS), VIP-PLS, and uninformative variable elimination combined with PLS (UVE-PLS) for the measurement of soil total nitrogen (TN) and organic matter (OM) using Vis-NIR spectroscopy. The dataset consisted of 195 soil samples collected from eight towns in Wencheng County, Zhejiang Province, China. The entire data set was split randomly into calibration set and prediction set. The calibration set was composed of 120 samples, while the prediction set included 75 samples. The best prediction results were obtained by the VIP-RPLS model. The coefficient of determination (R2) and residual prediction deviation (RPD) were respectively 0.85, 0.86 and 2.6%, 2.7% for soil TN and OM. The results indicate that VIP-RPLS is able to capture the effective information from the latest modeling sample by recursively updating the effective variables. The proposed method VIP-RPLS has the advantages of better performance for Vis-NIR prediction of soil N and OM compared with other methods in this work. PMID:25474936

  6. Influence of data preprocessing on the quantitative determination of nutrient content in poultry manure by near infrared spectroscopy.

    PubMed

    Chen, L J; Xing, L; Han, L J

    2010-01-01

    With increasing concern over potential polltion from farm wastes, there is a need for rapid and robust methods that can analyze livestock manure nutrient content. The near infrared spectroscopy (NIRS) method was used to determine nutrient content in diverse poultry manure samples (n=91). Various standard preprocessing methods (derivatives, multiplicative scatter correction, Savitsky-Golay smoothing, and standard normal variate) were applied to reduce data systemic noise. In addition, a new preprocessing method known as direct orthogonal signal correction (DOSC) was tested. Calibration models for ammonium nitrogen, total potassium, total nitrogen, and total phosphorus were developed with the partial least squares (PLS) method. The results showed that all the preprocessed data improved prediction results compared with the non-preprocessing method. Compared with the other preprocessing methods, the DOSC method gave the best results. The DOSC method achieved moderately successful prediction for ammonium nitrogen, total nitrogen, and total phosphorus. However, all preprocessing methods did not provide reliable prediction for total potassium. This indicates the DOSC method, especially combined with other preprocessing methods, needs further study to allow a more complete predictive analysis of manure nutrient content. PMID:21043290

  7. Quantitative analysis of toxic metals lead and cadmium in water jet by laser-induced breakdown spectroscopy

    SciTech Connect

    Cheri, M. Sadegh; Tavassoli, S. H.

    2011-03-20

    Laser-induced breakdown spectroscopy (LIBS) has been applied to the analysis of toxic metals Pb and Cd in Pb(NO{sub 3}){sub 2} and Cd(NO{sub 3}){sub 2}.4H{sub 2}O aqueous solutions, respectively. The plasma is generated by focusing a nanosecond Nd:YAG ({lambda}=1064 nm) laser on the surface of liquid in the homemade liquid jet configuration. With an assumption of local thermodynamic equilibrium (LTE), calibration curves of Pb and Cd were obtained at different delay times between 1 to 5 {mu}s. The temporal behavior of limit of detections (LOD) was investigated and it is shown that the minimum LODs for Pb and Cd are 4 and 68 parts in 10{sup 6} (ppm), respectively. In order to demonstrate the correctness of the LTE assumption, plasma parameters including plasma temperature and electron density are evaluated, and it is shown that the LTE condition is satisfied at all delay times.

  8. Brain Volume and Metabolism in Fetuses with Congenital Heart Disease: Evaluation with Quantitative Magnetic Resonance Imaging and Spectroscopy

    PubMed Central

    Limperopoulos, Catherine; Tworetzky, Wayne; McElhinney, Doff B.; Newburger, Jane W.; Brown, David W.; Robertson, Richard L.; Guizard, Nicolas; McGrath, Ellen; Geva, Judith; Annese, David; Dunbar-Masterson, Carolyn; Trainor, Bethany; Laussen, Peter C.; du Plessis, Adré J.

    2010-01-01

    Background Adverse neurodevelopmental outcome is an important source of morbidity in children with congenital heart disease (CHD). A significant proportion of newborns with complex CHD have abnormalities of brain size, structure, and/or function, suggesting that antenatal factors may contribute to childhood neurodevelopmental morbidity. Methods and Results Brain volume and metabolism were compared prospectively between 55 fetuses with CHD and 50 normal fetuses using 3-D volumetric magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (1H-MRS). Fetal intracranial cavity (ICV), cerebrospinal fluid, and total brain volumes (TBV) were measured by manual segmentation. 1H-MRS was used to measure the cerebral N-acetyl aspartate:choline ratio (NAA:Cho) and identify cerebral lactate. Complete fetal echocardiograms were performed. Gestational age (GA) at MRI ranged from 25 1/7 to 37 1/7 weeks (median 30 weeks). During the third trimester, there were progressive and significant declines in GA-adjusted TBV and ICV in CHD fetuses relative to controls. NAA:Cho increased progressively over the third trimester in normal fetuses, but the rate of rise was significantly slower (p<0.001) in CHD fetuses. On multivariable analysis adjusting for GA and weight percentile, cardiac diagnosis and percentage of combined ventricular output through the aortic valve were independently associated with TBV. Independent predictors of lower NAA:Cho included diagnosis, absence of antegrade aortic arch flow, and evidence of cerebral lactate (p<0.001). Conclusions Third-trimester fetuses with some forms of CHD have smaller GA- and weight-adjusted TBV than normal fetuses, and evidence of impaired neuroaxonal development and metabolism. Hemodynamic factors may play an important role in this abnormal development. PMID:20026783

  9. Quantitative proton magnetic resonance spectroscopy detects abnormalities in dorsolateral prefrontal cortex and motor cortex of patients with frontotemporal lobar degeneration

    PubMed Central

    Chawla, Sanjeev; Wang, Sumei; Moore, Peachie; Woo, John H.; Elman, Lauren; McCluskey, Leo F.; Melhem, Elias R.; Grossman, Murray

    2010-01-01

    Frontotemporal lobar degeneration (FTLD) is a neurodegenerative disease of the frontal and temporal neocortex. The single most common pathology underlying FTLD is neuronal degeneration with ubiquitin-positive but tau-negative inclusions consisting of Tar DNA binding proteins (TDP-43). Inclusions containing TDP-43 in neurons are also the most common pathology underlying motor neuron disease (MND). The present study tested the hypothesis that abnormal metabolite patterns within the dorsolateral prefrontal cortex (DLPFC) as well as the motor cortex (MC) may be observed in FTLD patients without motor disorders, using proton magnetic resonance spectroscopy (1H MRS). Twenty-six FTLD patients with cognitive damage and ten controls underwent multivoxel 1H MRS. Absolute concentrations of N-acetyl aspartate (NAA), creatine (Cr), choline (Cho) and myo-inositol (mI) were measured from the DLPFC, the MC and the parietal cortex (PC, an internal control). Statistical analyses were performed for group differences between FTLD patients and controls. Comparisons were also made across brain regions (PC and DLPFC; PC and MC) within FTLD patients. Significant reductions in NAA and Cr along with increased Cho and mI were observed in the DLPFC of FTLD patients compared to controls. Significantly lower NAA and higher Cho were also observed in the MCs of patients as compared to controls. Within the FTLD patients, both the MC and the DLPFC exhibited significantly decreased NAA and elevated Cho compared to the PC. However, only the DLPFC had significantly lower Cr and higher mI. Abnormal metabolite pattern from the MC supports the hypothesis that FTLD and MND may be closely linked. PMID:19688233

  10. A quantitative study of bioenergetics in skeletal muscle lacking carbonic anhydrase III using 31P magnetic resonance spectroscopy

    PubMed Central

    Liu, M.; Walter, G. A.; Pathare, N. C.; Forster, R. E.; Vandenborne, K.

    2007-01-01

    Oxidative slow skeletal muscle contains carbonic anhydrase III in high concentration, but its primary function remains unknown. To determine whether its lack handicaps energy metabolism and/or acid elimination, we measured the intracellular pH and energy phosphates by 31P magnetic resonance spectroscopy in hind limb muscles of wild-type and CA III knockout mice during and after ischemia and intense exercise (electrical stimulation). Thirty minutes of ischemia caused phosphocreatine (PCr) to fall and Pi to rise while pH and ATP remained constant in both strains of mice. PCr and Pi kinetics during ischemia and recovery were not significantly different between the two genotypes. From this we conclude that under neutral pH conditions resting muscle anaerobic metabolism, the rate of the creatine kinase reaction, intracellular buffering of protons, and phosphorylation of creatine by mitochondrial oxygen metabolism are not influenced by the lack of CA III. Two minutes of intense stimulation of the mouse gastrocnemius caused PCr, ATP, and pH to fall and ADP and Pi to rise, and these changes, with the exception of ATP, were all significantly larger in the CA III knockouts. The rate of return of pH and ADP to control values was the same in wild-type and mutant mice, but in the mutants PCr and Pi recovery were delayed in the first minute after stimulation. Because the tension decrease during fatigue is known to be the same in the two genotypes, we conclude that a lack of CA III impairs mitochondrial ATP synthesis. PMID:17182736

  11. Early metabolic development of posteromedial cortex and thalamus in humans analyzed via in vivo quantitative magnetic resonance spectroscopy.

    PubMed

    Degnan, Andrew J; Ceschin, Rafael; Lee, Vince; Schmithorst, Vincent J; Blüml, Stefan; Panigrahy, Ashok

    2014-11-01

    The posteromedial cortex (PMC) including the posterior cingulate, retrosplenial cortex, and medial parietal cortex/precuneus is an epicenter of cortical interactions in a wide spectrum of neural activity. Anatomic connections between PMC and thalamic components have been established in animal studies, but similar studies do not exist for the fetal and neonatal period. Magnetic resonance spectroscopy (MRS) allows for noninvasive measurement of metabolites in early development. Using single-voxel 3-T MRS, healthy term neonates (n?=?31, mean postconception age 41.5 weeks?±?3.8 weeks) were compared with control children (n?=?23, mean age 9.4 years?±?5.1 years) and young adults (n?=?10, mean age 24.1 years?±?2.6 years). LCModel-based calculations compared metabolites within medial parietal gray matter (colocalizing to the PMC), posterior thalamus, and parietal white matter voxels. Common metabolic changes existed for neuronal-axonal maturation and structural markers in the PMC, thalamus, and parietal white matter with increasing NAA and glutamate and decreasing myoinositol and choline with age. Key differences in creatine and glucose metabolism were noted in the PMC, in contrast to the thalamic and parietal white matter locations, suggesting a unique role of energy metabolism. Significant parallel metabolite developmental changes of multiple other metabolites including aspartate, glutamine, and glutathione with age were present between PMC and parietal white matter but not between PMC and thalamus. These findings offer insight into the metabolic architecture of the interface between structural and functional topology of brain networks. Further investigation unifying metabolic changes with functional and anatomic pathways may further enhance the understanding of the PMC in posterior default mode network development. PMID:24888973

  12. Quantitative X-ray photoelectron spectroscopy-based depth profiling of bioleached arsenopyrite surface by Acidithiobacillus ferrooxidans

    NASA Astrophysics Data System (ADS)

    Zhu, Tingting; Lu, Xiancai; Liu, Huan; Li, Juan; Zhu, Xiangyu; Lu, Jianjun; Wang, Rucheng

    2014-02-01

    In supergene environments, microbial activities significantly enhance sulfide oxidation and result in the release of heavy metals, causing serious contamination of soils and waters. As the most commonly encountered arsenic mineral in nature, arsenopyrite (FeAsS) accounts for arsenic contaminants in various environments. In order to investigate the geochemical behavior of arsenic during microbial oxidation of arsenopyrite, (2 3 0) surfaces of arsenopyrite slices were characterized after acidic (pH 2.00) and oxidative decomposition with or without an acidophilic microorganism Acidithiobacillus ferrooxidans. The morphology as well as chemical and elemental depth profiles of the oxidized arsenopyrite surface were investigated by scanning electron microscopy and X-ray photoelectron spectroscopy. With the mediation of bacteria, cell-shaped and acicular pits were observed on the reacted arsenopyrite surface, and the concentration of released arsenic species in solution was 50 times as high as that of the abiotic reaction after 10 days reaction. Fine-scale XPS depth profiles of the reacted arsenopyrite surfaces after both microbial and abiotic oxidation provided insights into the changes in chemical states of the elements in arsenopyrite surface layers. Within the 450 nm surface layer of abiotically oxidized arsenopyrite, Fe(III)-oxides appeared and gradually increased towards the surface, and detectable sulfite and monovalent arsenic appeared above 50 nm. In comparison, higher contents of ferric sulfate, sulfite, and arsenite were found in the surface layer of approximately 3 ?m of the microbially oxidized arsenopyrite. Intermediates, such as Fe(III)-AsS and S0, were detectable in the presence of bacteria. Changes of oxidative species derived from XPS depth profiles show the oxidation sequence is Fe > As = S in abiotic oxidation, and Fe > S > As in microbial oxidation. Based on these results, a possible reaction path of microbial oxidation was proposed in a concept model.

  13. Microscopic emission and reflectance thermal infrared spectroscopy: instrumentation for quantitative in situ mineralogy of complex planetary surfaces.

    PubMed

    Edwards, C S; Christensen, P R

    2013-04-10

    The diversity of investigations of planetary surfaces, especially Mars, using in situ instrumentation over the last decade is unprecedented in the exploration history of our solar system. The style of instrumentation that landed spacecraft can support is dependent on several parameters, including mass, power consumption, instrument complexity, cost, and desired measurement type (e.g., chemistry, mineralogy, petrology, morphology, etc.), all of which must be evaluated when deciding an appropriate spacecraft payload. We present a laboratory technique for a microscopic emission and reflectance spectrometer for the analysis of martian analog materials as a strong candidate for the next generation of in situ instruments designed to definitively assess sample mineralogy and petrology while preserving geologic context. We discuss the instrument capabilities, signal and noise, and overall system performance. We evaluate the ability of this instrument to quantitatively determine sample mineralogy, including bulk mineral abundances. This capability is greatly enhanced. Whereas the number of mineral components observed from existing emission spectrometers is high (often >5 to 10 depending on the number of accessory and alteration phases present), the number of mineral components at any microscopic measurement spot is low (typically <2 to 3). Since this style of instrument is based on a long heritage of thermal infrared emission spectrometers sent to orbit (the thermal emission spectrometer), sent to planetary surfaces [the mini-thermal emission spectrometers (mini-TES)], and evaluated in laboratory environments (e.g., the Arizona State University emission spectrometer laboratory), direct comparisons to existing data are uniquely possible with this style of instrument. The ability to obtain bulk mineralogy and atmospheric data, much in the same manner as the mini-TESs, is of significant additional value and maintains the long history of atmospheric monitoring for Mars. Miniaturization of this instrument has also been demonstrated, as the same microscope objective has been mounted to a flight-spare mini-TES. Further miniaturization of this instrument is straightforward with modern electronics, and the development of this instrument as an arm-mounted device is the end goal. PMID:23670748

  14. A meta-classifier for detecting prostate cancer by quantitative integration of in vivo magnetic resonance spectroscopy and magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Viswanath, Satish; Tiwari, Pallavi; Rosen, Mark; Madabhushi, Anant

    2008-03-01

    Recently, in vivo Magnetic Resonance Imaging (MRI) and Magnetic Resonance Spectroscopy (MRS) have emerged as promising new modalities to aid in prostate cancer (CaP) detection. MRI provides anatomic and structural information of the prostate while MRS provides functional data pertaining to biochemical concentrations of metabolites such as creatine, choline and citrate. We have previously presented a hierarchical clustering scheme for CaP detection on in vivo prostate MRS and have recently developed a computer-aided method for CaP detection on in vivo prostate MRI. In this paper we present a novel scheme to develop a meta-classifier to detect CaP in vivo via quantitative integration of multimodal prostate MRS and MRI by use of non-linear dimensionality reduction (NLDR) methods including spectral clustering and locally linear embedding (LLE). Quantitative integration of multimodal image data (MRI and PET) involves the concatenation of image intensities following image registration. However multimodal data integration is non-trivial when the individual modalities include spectral and image intensity data. We propose a data combination solution wherein we project the feature spaces (image intensities and spectral data) associated with each of the modalities into a lower dimensional embedding space via NLDR. NLDR methods preserve the relationships between the objects in the original high dimensional space when projecting them into the reduced low dimensional space. Since the original spectral and image intensity data are divorced from their original physical meaning in the reduced dimensional space, data at the same spatial location can be integrated by concatenating the respective embedding vectors. Unsupervised consensus clustering is then used to partition objects into different classes in the combined MRS and MRI embedding space. Quantitative results of our multimodal computer-aided diagnosis scheme on 16 sets of patient data obtained from the ACRIN trial, for which corresponding histological ground truth for spatial extent of CaP is known, show a marginally higher sensitivity, specificity, and positive predictive value compared to corresponding CAD results with the individual modalities.

  15. Quantitative surface plasmon resonance spectroscopy as a probe of adsorption, diffusion, and self-assembly of biopolymers and oligonucleotides at interfaces

    NASA Astrophysics Data System (ADS)

    Georgiadis, Rosina M.; Peterlinz, Kevin A.

    1998-04-01

    In situ surface plasmon resonance (SPR) spectroscopy methods are used to investigate the process by which thin films form at solid/solutions interfaces. Representative kinetics data are presented for the adsorption of two different types of molecular adsorbates onto gold substrates. The first system involves adsorption of alginic acid, an acidic polysaccharide. The second system involves the adsorption of single-stranded DNA oligomers. Quantitative two-color SPR kinetics data are of sufficiently high quality that distinguishing between various kinetics models is now possible. Commonly used Langmuir adsorption models cannot adequately describe some of the adsorption kinetics data. However, these data are very well described by a model developed to include diffusion at the interface as well as adsorption/description. This more general model is found to work very well for a variety of chemically distinct adsorbate/substrate systems. Analysis of high quality in- situ SPR data can identify distinct differences in kinetics and many be useful for distinguishing between different types of adsorbate/surface interactions. This capability may prove very useful for gaining insight into mechanistic differences in the process by which molecular films at solid/liquid interfaces.

  16. Quantitative analyses of oxidation states for cubic SrMnO3 and orthorhombic SrMnO2.5 with electron energy loss spectroscopy

    NASA Astrophysics Data System (ADS)

    Kobayashi, S.; Tokuda, Y.; Mizoguchi, T.; Shibata, N.; Sato, Y.; Ikuhara, Y.; Yamamoto, T.

    2010-12-01

    The oxidation state of Mn in cubic SrMnO3 and orthorhombic SrMnO2.5 was investigated by electron energy loss (EEL) spectroscopy. Change in the oxidation state of Mn produced some spectral changes in the O-K edge as well as in the Mn-L2,3 edge EEL spectra. This study demonstrated that the oxidation state of Mn and the amount of oxygen vacancies in cubic SrMnO3 and orthorhombic SrMnO2.5 could be quantified by analyzing the features of the O-K edge spectrum and the Mn L3/L2 ratio in the Mn-L2,3 edge spectrum. Our quantitative analysis showed that the spectral changes in the Mn-L2,3 edge were mainly caused by the oxidation state of Mn, whereas those in the O-K edge could be sensitive to both the oxidation state of Mn and to lattice distortions.

  17. Relationship between the v?PO?/amide III ratio assessed by Raman spectroscopy and the calcium content measured by quantitative backscattered electron microscopy in healthy human osteonal bone.

    PubMed

    Roschger, Andreas; Gamsjaeger, Sonja; Hofstetter, Birgit; Masic, Admir; Blouin, Stéphane; Messmer, Phaedra; Berzlanovich, Andrea; Paschalis, Eleftherios P; Roschger, Paul; Klaushofer, Klaus; Fratzl, Peter

    2014-06-01

    Raman microspectroscopy and quantitative backscattered electron imaging (qBEI) of bone are powerful tools to investigate bone material properties. Both methods provide information on the degree of bone matrix mineralization. However, a head-to-head comparison of these outcomes from identical bone areas has not been performed to date. In femoral midshaft cross sections of three women, 99 regions (20×20 ?m²) were selected inside osteons and interstitial bone covering a wide range of matrix mineralization. As the focus of this study was only on regions undergoing secondary mineralization, zones exhibiting a distinct gradient in mineral content close to the mineralization front were excluded. The same regions were measured by both methods. We found a linear correlation (R²=0.75) between mineral/matrix as measured by Raman spectroscopy and the wt.?%Mineral/(100-wt.?%Mineral) as obtained by qBEI, in good agreement with theoretical estimations. The observed deviations of single values from the linear regression line were determined to reflect biological heterogeneities. The data of this study demonstrate the good correspondence between Raman and qBEI outcomes in describing tissue mineralization. The obtained correlation is likely sensitive to changes in bone tissue composition, providing an approach to detect potential deviations from normal bone. PMID:24919447

  18. Parallel ?-sheet vibrational couplings revealed by 2D IR spectroscopy of an isotopically labeled macrocycle: Quantitative benchmark for the interpretation of amyloid and protein infrared spectra

    PubMed Central

    Woys, Ann Marie; Almeida, Aaron M.; Wang, Lu; Chiu, Chi Cheng; McGovern, Michael; de Pablo, Juan J.; Skinner, James L.; Gellman, Samuel H.; Zanni, Martin T.

    2012-01-01

    Infrared spectroscopy is playing an important role in the elucidation of amyloid fiber formation, but the coupling models that link spectra to structure are not well tested for parallel ?-sheets. Using a synthetic macrocycle that enforces a two stranded parallel ?-sheet conformation, we measured the lifetimes and frequency for six combinations of doubly 13C=18O labeled amide I modes using 2D IR spectroscopy. The average vibrational lifetime of the isotope labeled residues was 550 fs. The frequen cies of the labels ranged from 1585 to 1595 cm?1, with the largest frequency shift occurring for in-register amino acids. The 2D IR spectra of the coupled isotope labels were calculated from molecular dynamics simulations of a series of macrocycle structures generated from replica exchange dynamics to fully sample the conformational distribution. The models used to simulate the spectra include through-space coupling, through-bond coupling, and local frequency shifts caused by environment electrostatics and hydrogen bonding. The calculated spectra predict the linewidths and frequencies nearly quantitatively. Historically, the characteristic features of ?-sheet infrared spectra have been attributed to through-space couplings such as transition dipole coupling. We find that frequency shifts of the local carbonyl groups due to nearest neighbor couplings and environmental factors are more important, while the through space couplings dictate the spectral intensities. As a result, the characteristic absorption spectra empirically used for decades to assign parallel ?-sheet secondary structure arises because of a redistribution of oscillator strength, but the through-space couplings do not themselves dramatically alter the frequency distribution of eigenstates much more than already exists in random coil structures. Moreover, solvent exposed residues have amide I bands with >20 cm?1 linewidth. Narrower linewidths indicate that the amide I backbone is solvent protected inside the macrocycle. This work provides calculated and experimentally verified couplings for parallel ?-sheets that can be used in structure-based models to simulate and interpret the infrared spectra of ?-sheet containing proteins and protein assemblies, such as amyloid fibers. PMID:23113791

  19. Quantitative analysis in gas chromatography/low power atmospheric-pressure helium microwave-induced plasma atomic emission interferometry and ion cyclotron resonance mass spectroscopy

    SciTech Connect

    Loo, J.F.

    1990-01-01

    The development of experimental and data analysis techniques for quantitative analysis in gas chromatography/low power atmospheric pressure helium microwave-induced plasma atomic emission interferometry (GC/HeMIPAEI) and ion cyclotron resonance mass spectroscopy (ICR/MS) is presented. A discussion of interferometric data analysis by discrete and fast Fourier transform (DFT and FFT, respectively) is given. Additionally, the use of two techniques (the maximum entropy method, or MEM, and linear prediction, or LP) that have shown to produce results superior to those from the FFT is shown for synthetic and experimental NMR, optical, and mass spectral data. Visual spectral comparisons, performance results as compared to known spectral parameters, and a methodology for the implementation of the linear prediction technique is given. A low-power HeMIP was constructed and used as the excitation source for an AEI detector for gas chromatography. In general, HeMIPs have the advantage of being able to excite non-metal atoms, which comprise a large fraction of the molecules used in typical organic GC analysis. Sensitivity, detection limits, their dependence on microwave power values, and elemental emission ratios are tabulated for a series of test compounds. Results show that elemental emission ratios are independent of the structure of the compound used in this study. Suggestions for further development, from the use of a concentric-flow torch and optical filters to the removal of oxygen through the use of ultra-high purity helium, are presented. Through the use of coherent pulsed excitation, electronic quadrature detection, and data analysis by linear prediction, ICR/MS relative abundance error values for the principal isotopes of krypton have been calculated to be less than 1%.

  20. Application of NIR spectroscopy for the quality control of mangosteen pericarp powder: quantitative analysis of alpha-mangostin in mangosteen pericarp powder and capsule.

    PubMed

    Peerapattana, Jomjai; Otsuka, Kuniko; Otsuka, Makoto

    2013-07-01

    Near-infrared spectroscopy (NIR) was applied to the quantitative analysis of the concentration of alpha-mangostin (aM) in mangosteen pericarp powder (MP). The predicted results from the partial least squares chemometric method of various pretreatment data were compared to obtain the best calibration model. Two different types of containers (transparent capsules and glass vials) filled with the same samples were measured. For MP mixture in vials, the calibration model involving nine principal components (PC) could predict the amount of aM most accurately based on non-pretreatment spectral data. For MP mixture in capsules, the calibration model involving nine PC could predict the amount of aM most accurately based on first-derivative pretreatment spectra. The relationships of the calibration models for both samples had sufficiently linear plots. The standard error of cross-validation for the MP mixture in vials was lower and the R(2) values of validation were higher compared to the MP mixture in capsules. The equation for prediction of the concentration of aM in MP mixtures in vials is y = 0.9775x + 0.0425 with R(2) = 0.9950 and for those in capsules is y = 1.0264x + 0.0126 with R(2) = 0.9898. Both validation results indicated that the concentrations of aM in MP mixtures were predicted with sufficient accuracy and repeatability. NIR can be a useful tool for the quality control of herbal medicine in powder form without any sample preparation. The type and the shape of the container should be considered to obtain more accurate data. PMID:22926311

  1. Chiroptical Spectroscopy

    NASA Astrophysics Data System (ADS)

    Gurst, Jerome E.

    1995-09-01

    A brief review of the literature, and Chemical and Engineering News in particular, reveals that the determination and use of optical activity is of increasing importance in today's commercial and research laboratories. The classical technique is to measure [alpha]D using a manual or recording polarimeter to provide a single value, the specific rotation at 589 nm. A spectropolarimeter can be used to determine optical activity through the UV-Visible spectrum (Optical Rotatory Dispersion [ORD]). At wavelengths far removed from electronic absorption bands, optical activity arises from circular birefringence, or the difference in the refractive index for left- and right-circularly polarized light; i.e., nL - nR does not equal zero for chiral materials. If the optical activity is measured through an absorption band, complex behavior is observed (a Cotton Effect curve). At an absorption band, chiral materials exhibit circular dichroism (CD), or a difference in the absorption of left- and right-circularly polarized light; epsilon L minus epsilon R does not equal zero. If the spectropolarimeter is set for the measurement of CD spectra, one observes what appears to be a UV-Vis spectrum except that some absorption bands are positive while others may be negative. Just as enantiomers have specific rotations that are equal and opposite at 589 nm (sodium D line), rotations are equal and opposite at all wavelengths, and CD measurements are equal and opposite at all wavelengths. Figure 1 shows the ORD curves for the enantiomeric carvones while Figure 2 contains the CD curves. The enantiomer of carvone that has the positive [alpha]D is obtained from caraway seeds and is known to have the S-configuration while the R-enantiomer is found in spearmint oil. Figure 1. ORD of S-(+)- and R-(-)-carvones Figure 2. CD of S-(+)- and R-(-)-carvones While little can be done to correlate stereochemistry with [alpha]D values, chiroptical spectroscopy (ORD and/or CD) often can be used to assign absolute or relative configuration, or it can be useful in conformational analyses (1). Experiments are being developed for undergraduates that involve the synthesis of chiral materials, or the resolution of chiral materials, including organic compounds, inorganic complexes and organometallic compounds. Both classical and chiral HPLC resolutions are being tested. Once prepared, these chiral materials are studied by various techniques including NMR, Raman, IR, UV-VIS, differential scanning calorimetry (DSC), and chiroptical techniques. Molecular mechanics calculations are included (using PCModel which is available from Serena Software, Bloomington, IN.) when appropriate. Examples include some traditional experiments; i.e., the preparation and resolution of the tris-ethylenediaminecobalt complexes as well as some not now found in typical undergraduate laboratory manuals. For example, the resolution of trans-1,2-diaminocyclohexane and subsequent conversion to the bis-Schiff base with para-dimethylamino-benzaldehyde. These Schiff bases have been studied by Nakanishi (2) using the exciton coupling method. AcknowledgmentThis work was supported partially under the award DUE-9351122 from the National Science Foundation Division of Undergraduate Education Instrumentation and Laboratory Improvement Program. Literature Cited Eliel, E.; Wilen, S. H. Stereochemistry of Organic Compounds; J. Wiley & Sons, Inc.: New York, 1994; Djerassi, C. Optical Rotary Dispersion; McGraw-Hill Book Company, Inc., New York, 1960.; Crabbe, P. Optical Rotary Dispersion and Circular Dichroism in Organic Chemistry; Holden-Day: San Francisco, 1965. Gargiulo, D.; Cai, G.; Ikemoto, N.; Bozhkova, N.; Odingo, J. Berova, N. Nakanishi, K. Angew. Chemie Int. Ed. Engl. 1993, 32, 888-891.

  2. [Influence of silver/silicon dioxide on infrared absorption spectroscopy of sodium nitrate].

    PubMed

    Yang, Shi-Ling; Yue, Li; Jia, Zhi-Jun

    2014-09-01

    Quickly detecting of ocean nutrient was one important task in marine pollution monitoring. We discovered the application of surface-enhanced infrared absorption spectroscopy in the detection of ocean nutrient through researching the evaporation of sodium nitrate solution. The silicon dioxide (SiO2) with highly dispersion was prepared by Stober method, The silver/silica (Ag/SiO2) composite materials were prepared by mixing ammonia solution and silicon dioxide aqueous solution. Three kinds of composite materials with different surface morphology were fabricated through optimizing the experimental parameter and changing the experimental process. The surface morphology, crystal orientation and surface plasmon resonance were investigated by means of the scanning electronic microscope (SEM), X-ray diffraction (XRD), UV-Visible absorption spectrum and infrared ab- sorption spectroscopy. The SEM images showed that the sample A was purified SiO2, sample B and sample C were mixture of silver nanoparticle and silicon dioxide, while sample D was completed nanoshell structure. The absorption spectroscopy showed that there was surface plasmon resonance in the UV-visible region, while there was possibility of surface plasmon resonance in the Infrared absorption region. The effect of Ag/SiO2 composite material on the infrared absorption spectra of sodium nitrite solution was investigated through systematically analyzing the infrared absorption spectroscopy of sodium nitrate solution during its evaporation, i. e. the peak integration area of nitrate and the peak integration area of water molecule. The experimental results show that the integration area of nitrate was enhanced greatly during the evaporation process while the integration area of water molecule decreased continuously. The integration area of nitrate comes from the anti-symmetric stretch vibration and the enhancement of the vibration is attributed to the interface effect of Ag/SiO2 which is consistent with Jensen T.R's result. PMID:25532335

  3. Oriented single-crystal nuclear resonance vibrational spectroscopy of [Fe(TPP)(MI)(NO)] : quantitative sssessment of the trans effect of NO.

    SciTech Connect

    Lehnert, N.; Sage, J. T.; Silvernail, N.; Scheidt, W. R.; Alp, E. E.; Sturhahn, W.; Zhao, J. (X-Ray Science Division); (Univ. of Michigan); (Northeastern Univ.); (Univ. of Notre Dame)

    2010-01-01

    This paper presents oriented single-crystal Nuclear Resonance Vibrational Spectroscopy (NRVS) data for the six-coordinate (6C) ferrous heme-nitrosyl model complex [{sup 57}Fe(TPP)(MI)(NO)] (1; TPP{sup 2-} = tetraphenylporphyrin dianion; MI = 1-methylimidazole). The availability of these data enables for the first time the detailed simulation of the complete NRVS data, including the porphyrin-based vibrations, of a 6C ferrous heme-nitrosyl, using our quantum chemistry centered normal coordinate analysis (QCC-NCA). Importantly, the Fe-NO stretch is split by interaction with a porphyrin-based vibration into two features, observed at 437 and 472 cm{sup -1}. The 437 cm{sup -1} feature is strongly out-of-plane (oop) polarized and shows a {sup 15}N{sup 18}O isotope shift of 8 cm{sup -1} and is therefore assigned to v(Fe-NO). The admixture of Fe-N-O bending character is small. Main contributions to the Fe-N-O bend are observed in the 520-580 cm{sup -1} region, distributed over a number of in-plane (ip) polarized porphyrin-based vibrations. The main component, assigned to {delta}{sub ip}(Fe-N-O), is identified with the feature at 563 cm{sup -1}. The Fe-N-O bend also shows strong mixing with the Fe-NO stretching internal coordinate, as evidenced by the oop NRVS intensity in the 520-580 cm{sup -1} region. Very accurate normal mode descriptions of ?(Fe-NO) and {delta}{sub ip}(Fe-N-O) have been obtained in this study. These results contradict previous interpretations of the vibrational spectra of 6C ferrous heme-nitrosyls where the higher energy feature at {approx}550 cm{sup -1} had usually been associated with v(Fe-NO). Furthermore, these results provide key insight into NO binding to ferrous heme active sites in globins and other heme proteins, in particular with respect to (a) the effect of hydrogen bonding to the coordinated NO and (b) changes in heme dynamics upon NO coordination. [Fe(TPP)(MI)(NO)] constitutes an excellent model system for ferrous NO adducts of myoglobin (Mb) mutants where the distal histidine (His64) has been removed. Comparison to the reported vibrational data for wild-type (wt) Mb-NO then shows that the effect of H bonding to the coordinated NO is weak and mostly leads to a polarization of the {pi}/{pi}* orbitals of bound NO. In addition, the observation that {delta}{sub ip}(Fe-N-O) does not correlate well with ?(N-O) can be traced back to the very mixed nature of this mode. The Fe-N(imidazole) stretching frequency is observed at 149 cm{sup -1} in [Fe(TPP)(MI)(NO)], and spectral changes upon NO binding to five-coordinate ferrous heme active sites are discussed. The obtained high-quality force constants for the Fe-NO and N-O bonds of 2.57 and 11.55 mdyn/{angstrom} can further be compared to those of corresponding 5C species, which allows for a quantitative analysis of the {sigma} trans interaction between the proximal imidazole (His) ligand and NO. This is key for the activation of the NO sensor soluble guanylate cyclase. Finally, DFT methods are calibrated against the experimentally determined vibrational properties of the Fe-N-O subunit in 1. DFT is in fact incapable of reproducing the vibrational energies and normal mode descriptions of the Fe-N-O unit well, and thus, DFT-based predictions of changes in vibrational properties upon heme modification or other perturbations of these 6C complexes have to be treated with caution.

  4. Comparison between ultraviolet-visible and near-infrared elastic scattering spectroscopy of chemically induced melanomas in an animal model.

    PubMed

    A'Amar, Ousama M; Ley, Ronald D; Bigio, Irving J

    2004-01-01

    The work reported compares elastic scattering spectroscopy (ESS) for diagnosis of pigmented skin lesions in two spectral regions: UV-visible and near infrared (NIR). Given the known strong absorption by melanin in the near-UV to mid-visible range of the spectrum, such a comparison can help determine the optimum wavelength range of ESS for diagnosis of pigmented skin lesions. For this purpose, four South American opossums are treated with dimethylbenz(a)anthracene on multiple dorsal sites to induce both malignant melanomas and benign pigmented lesions. Skin lesions are examined in vivo with ESS using both UV-visible and NIR, with wavelength ranges of 330 to 900 nm and 900 to 1700 nm, respectively. Both portable systems use the same fiber optic probe geometry. ESS measurements are made on the lesions, and spectral differences are grouped by diagnosis from standard histopathological procedure. Both ESS datasets show strong spectral trends with the histopathological assignments, and the data suggest a model for the underlying basis of the spectral distinction between benign and malignant pigmented nevi. PMID:15568954

  5. Nanoscale investigation of the degradation mechanism of a historical chrome yellow paint by quantitative electron energy loss spectroscopy mapping of chromium species.

    PubMed

    Tan, Haiyan; Tian, He; Verbeeck, Jo; Monico, Letizia; Janssens, Koen; Van Tendeloo, Gustaaf

    2013-10-18

    Getting the picture: The investigation of 100?year old chrome yellow paint by transmission electron microscopy and spectroscopy has led to the identification of four types of core-shell particles. This nanoscale investigation has allowed a mechanism to be proposed for the darkening of some bright yellow colors in Van Gogh's paintings (e.g. in Falling leaves (Les Alyscamps), 1888). PMID:24039036

  6. Quantitative determination of wear metals in engine oils using laser-induced breakdown spectroscopy: A comparison between liquid jets and static liquids

    Microsoft Academic Search

    Pavel Yaroshchyk; Richard J. S. Morrison; Doug Body; Bruce L. Chadwick

    2005-01-01

    A comparison of laser-induced breakdown spectroscopy (LIBS) sensitivity in laminar liquid jets and at the surface of a static liquid has been performed. Limits of detection (LODs) have been estimated for Na, Mg, Al, Ca, Ti, V, Cr, Mn, Ni, Fe, Cu, Zn, Mo, Ag, Cd, and Ba under similar conditions using both experimental arrangements. LODs in liquid jets are

  7. Direct quantitative determination, using flameless atomic absorption spectroscopy, of metallic impurities and rare earths in nuclear solutions containing uranium, thorium, and fission products

    Microsoft Academic Search

    M. Gerardi; G. A. Pelliccia

    2009-01-01

    A method is described for direct quantitative determination of metallic and rare earths in nuclear solutions containing U, Th, and fission products from the ITREC reprocessing plant of the CNEN, CRN-Trisaia. Various tables summarize instrumental operating conditions, preparations of standards, detection limits and sensitivities, average relative standard deviation, analytical limits for the 22 investigated elements, maximum total tolerance of the

  8. Use of near infrared correlation spectroscopy for quantitation of surface iron, absorbed water and stored electronic energy in a suite of Mars soil analog materials

    NASA Technical Reports Server (NTRS)

    Coyne, Lelia M.; Banin, Amos; Carle, Glenn; Orenberg, James; Scattergood, Thomas

    1989-01-01

    A number of questions concerning the surface mineralogy and the history of water on Mars remain unresolved using the Viking analyses and Earth-based telescopic data. Identification and quantitation of iron-bearing clays on Mars would elucidate these outstanding issues. Near infrared correlation analysis, a method typically applied to qualitative and quantitative analysis of individual constituents of multicomponent mixtures, is adapted here to selection of distinctive features of a small, highly homologous series of Fe/Ca-exchanged montmorillonites and several kalinites. Independently determined measures of surface iron, relative humidity and stored electronic energy were used as constituent data for linear regression of the constituent vs. reflectance data throughout the spectral region 0.68 to 2.5 micrometers. High correlations were found in appropriate regions for all three constituents, though that with stored energy is still considered tenuous. Quantitation was improved using 1st and 2nd derivative spectra. High resolution data over a broad spectral range would be required to quantitatively identify iron-bearing clays by remotely sensed reflectance.

  9. Principles of Plasma Spectroscopy

    Microsoft Academic Search

    A. L. Osterheld

    1998-01-01

    This book gives a comprehensive treatment of plasma spectroscopy, the quantitative study of line and continuous radiation from high temperature plasmas. This highly interdisciplinary field combines elements of atomic, plasma and statistical physics, and has wide application to simulations and diagnostics of laboratory and astrophysical plasmas. Plasma spectroscopy is naturally intertwined with magnetic and inertial fusion energy science. Radiative processes

  10. A photophysical study of purines and theophylline by using laser-induced optoacoustic spectroscopy.

    PubMed

    Murgida, D H; Bilmes, G M; Erra-Balsells, R

    1996-11-01

    The photophysics of purinic compounds (purine, 6-methylpurine, 6-aminopurine [adenine], 6-chloropurine, 6-methoxypurine) and theophylline in acetonitrile solution were studied by pulsed laser-induced optoacoustic spectroscopy (LIOAS) exciting at 266 nm. The effect of O2, Xe and MnCl2 on the photophysical behavior of these compounds was studied; as well, the formation quantum yield of purine and 6-methylpurine triplet states were determined, with phi T = 0.88 +/- 0.03 for both compounds. Multiphotonic and depletion processes were observed at high laser fluences. In order to explain this behavior, theoretical UV-visible absorption electronic spectra from both the S0 and S1 state have been calculated for purines and theophylline by using the semiempirical PM3 and ZINDO/S methods. PMID:8931375

  11. Synthesis, characterization, spectroscopy, electronic and redox properties of a new nickel dithiolene system

    PubMed Central

    Basu, Partha; Nigam, Archana; Mogesa, Benjamin; Denti, Suzanne; Nemykin, Victor

    2010-01-01

    A new dithiolene ligand with 3,5-dibromo substituted phenyl groups was designed and synthesized. The protected form of the ligand was reacted with a nickel salt providing neutral Ni(S2C2(3,5-C6H3Br2)2)2 and anionic [Ni(S2C2(3,5-C6H3Br2)2)2]? isolated as a Bu4N+ salt. Both were characterized by UV-visible and IR spectroscopy and compared with the similar known molecular systems. They exhibit intense low-energy transitions that are characteristic of such systems. The electrochemical behavior of these molecules was investigated by cyclic voltammetry. PMID:21057604

  12. Detection and quantitative analysis of chemical species in Hanford tank materials using Raman spectroscopy technology: FY94, January 1, 1994--March 31, 1995

    SciTech Connect

    Vickers, T.J.; Mann, C. [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry

    1995-09-12

    This report provides a summary of work completed in FY-94 by FSU to develop and investigate the feasibility of using Raman spectroscopy with Hanford tank waste materials. Raman performance impacts from sample morphology, including the effects of absorption, particle size, density, color and refractive index, are discussed. An algorithm for relative species concentration measurement from Raman data is presented. An Algorithm for applying Raman to tank waste core screening is presented and discussed. A library of absorption and Raman spectra are presented that support this work.

  13. Quantitative Analysis of Microstructure in Polysiloxanes Using High Resolution Si29 NMR Spectroscopy: Investigation of Lot Variability in the LVM97 and HVM97 PDMS/PDPS Copolymers

    SciTech Connect

    ALAM, TODD M.

    2002-11-01

    The quantitative analysis of microstructure and sequence distribution in polysiloxane copolymers using high-resolution solution {sup 29}Si NMR is reported. Copolymers containing dimethylsiloxane (DMS) and diphenysiloxane (DPS) monomer units prepared with either high vinyl content (HVM) or low vinyl content (LVM) were analyzed. The average run length (R{sub exp}), the number average sequence length (l{sub A}, l{sub B}), along with the various linkage probabilities (p{sub AA}, p{sub AB}, p{sub BA}, and p{sub BB}) were determined for different production lots of the LVM97 and HVM97 samples to address the lot variability of microstructure in these materials.

  14. Determination of Three-Bond 1H3?– 31P Couplings in Nucleic Acids and Protein–Nucleic Acid Complexes by Quantitative JCorrelation Spectroscopy

    Microsoft Academic Search

    G. Marius Clore; Elizabeth C. Murphy; Angela M. Gronenborn; Ad Bax

    1998-01-01

    A new sensitive two-dimensional quantitativeJcorrelation experiment is described for measuring3JH3?–Pcouplings in nucleic acids and protein–nucleic acid complexes. The method is based on measuring the change in intensity of the1H–1H cross peaks in a constant-time1H–1H COSY experiment which occurs in the presence and absence of3JH3?–Pdephasing during the constant-time evolution period. For protein–nucleic acid complexes where the protein is13C-labeled but the nucleic

  15. In-line monitoring of extraction process of scutellarein from Erigeron breviscapus (vant.) Hand-Mazz based on qualitative and quantitative uses of near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Wu, Yongjiang; Jin, Ye; Ding, Haiying; Luan, Lianjun; Chen, Yong; Liu, Xuesong

    2011-09-01

    The application of near-infrared (NIR) spectroscopy for in-line monitoring of extraction process of scutellarein from Erigeron breviscapus (vant.) Hand-Mazz was investigated. For NIR measurements, two fiber optic probes designed to transmit NIR radiation through a 2 mm pathlength flow cell were utilized to collect spectra in real-time. High performance liquid chromatography (HPLC) was used as a reference method to determine scutellarein in extract solution. Partial least squares regression (PLSR) calibration model of Savitzky-Golay smoothing NIR spectra in the 5450-10,000 cm -1 region gave satisfactory predictive results for scutellarein. The results showed that the correlation coefficients of calibration and cross validation were 0.9967 and 0.9811, respectively, and the root mean square error of calibration and cross validation were 0.044 and 0.105, respectively. Furthermore, both the moving block standard deviation (MBSD) method and conformity test were used to identify the end point of extraction process, providing real-time data and instant feedback about the extraction course. The results obtained in this study indicated that the NIR spectroscopy technique provides an efficient and environmentally friendly approach for fast determination of scutellarein and end point control of extraction process.

  16. Quantitative depth-resolved photoelectron spectroscopy analysis of the interaction of energetic oxygen ions with the beryllium-tungsten alloy Be2W

    NASA Astrophysics Data System (ADS)

    Köppen, M.; Oberkofler, M.; Riesch, J.; Schmid, K.; Vollmer, A.; Linsmeier, Ch.

    2013-07-01

    The chemical reactions during the implantation of oxygen ions into a thin beryllium-tungsten alloy layer on a beryllium substrate and subsequent annealing are investigated by depth-resolved chemical analysis using X-ray photoelectron spectroscopy. By using variable photon energies at a synchrotron, identical kinetic energies of the photoelectrons from the different core levels are selected. This enables a chemical analysis at identical depth intervals for all core levels. From these sets of photoelectron spectra chemically resolved depth profiles are determined. The depth profiles allow an interpretation of the reaction and diffusion steps during implantation and annealing steps. This leads to a detailed understanding of the complex processes in a multi-component solid.

  17. Improvement of the inverse-gated-decoupling sequence for a faster quantitative analysis of various samples by 13C NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Giraudeau, Patrick; Baguet, Evelyne

    2006-05-01

    The inverse-gated-decoupling sequence enables quantitative 1H decoupled 13C spectra to be obtained. We modified this sequence so as to obtain the same result in less time for molecules containing carbons with various relaxation properties. For that, we determined the optimal 13C longitudinal-magnetization initial value for a faster relaxation while 1H decoupler is stopped. This value can be calculated precisely via the nuclear Overhauser effects, the longitudinal relaxation times, together with the determination of the relaxation rate constants of carbons while 1H are out of equilibrium. A supplementary delay of 1H decoupling and/or a series of selective pulses applied at the beginning of the recovery delay allow an acceleration of 13C longitudinal relaxation. We applied this method to the molecule of vanillin. The simultaneous quantification of all carbons was carried out with a recovery delay divided by two compared to the usual sequence.

  18. Application of a series of artificial neural networks to on-site quantitative analysis of lead into real soil samples by laser induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    El Haddad, J.; Bruyère, D.; Ismaël, A.; Gallou, G.; Laperche, V.; Michel, K.; Canioni, L.; Bousquet, B.

    2014-07-01

    Artificial neural networks were applied to process data from on-site LIBS analysis of soil samples. A first artificial neural network allowed retrieving the relative amounts of silicate, calcareous and ores matrices into soils. As a consequence, each soil sample was correctly located inside the ternary diagram characterized by these three matrices, as verified by ICP-AES. Then a series of artificial neural networks were applied to quantify lead into soil samples. More precisely, two models were designed for classification purpose according to both the type of matrix and the range of lead concentrations. Then, three quantitative models were locally applied to three data subsets. This complete approach allowed reaching a relative error of prediction close to 20%, considered as satisfying in the case of on-site analysis.

  19. Quantitative assessment of brain tissue oxygenation in porcine models of cardiac arrest and cardiopulmonary resuscitation using hyperspectral near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Lotfabadi, Shahin S.; Toronov, Vladislav; Ramadeen, Andrew; Hu, Xudong; Kim, Siwook; Dorian, Paul; Hare, Gregory M. T.

    2014-03-01

    Near-infrared spectroscopy (NIRS) is a non-invasive tool to measure real-time tissue oxygenation in the brain. In an invasive animal experiment we were able to directly compare non-invasive NIRS measurements on the skull with invasive measurements directly on the brain dura matter. We used a broad-band, continuous-wave hyper-spectral approach to measure tissue oxygenation in the brain of pigs under the conditions of cardiac arrest, cardiopulmonary resuscitation (CPR), and defibrillation. An additional purpose of this research was to find a correlation between mortality due to cardiac arrest and inadequacy of the tissue perfusion during attempts at resuscitation. Using this technique we measured the changes in concentrations of oxy-hemoglobin [HbO2] and deoxy-hemoglobin [HHb] to quantify the tissue oxygenation in the brain. We also extracted cytochrome c oxidase changes ?[Cyt-Ox] under the same conditions to determine increase or decrease in cerebral oxygen delivery. In this paper we proved that applying CPR, [HbO2] concentration and tissue oxygenation in the brain increase while [HHb] concentration decreases which was not possible using other measurement techniques. We also discovered a similar trend in changes of both [Cyt-Ox] concentration and tissue oxygen saturation (StO2). Both invasive and non-invasive measurements showed similar results.

  20. A quantitative analysis of protein secondary structure of photosystem II particles and light-harvesting complex of chloroplast thylakoid membranes by FT-IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Nahar, S.; Tajmir-Riahi, H. A.; Carpentier, R.

    1994-12-01

    We report the preliminary results of protein conformational analysis of photosystem II (PSII) particles and light-harvesting complex (LHC-II) of chloroplast thylakoid membranes isolated from fresh spinach in aqueous solution at neutral pH. FT-IR spectroscopy, with its self-deconvolution and second derivative resolution enhancement as well as curve-fitting procedures, was used in the amide I region (1700-1600 cm-1), to determine the amount of each conformation present in coexistence. Spectroscopic data have shown the domination of the ?-helix (1656 cm-1) to be a major conformational component in both PSII (64%) and LHC-II (48%) systems. The ?-sheet (1626-1640 cm-1), with 17% for PSII and 21% for LHC-II, and the turn structure (1670-1680 cm-1), with 23% for LHC-II and 13% for PSII, with ?-antiparallel (1689-1691 cm-1) 8% for LHC-II and 6% for PSII, were the minor conformations present in aqueous solution.

  1. Quantitative analysis of deconvolved X-ray absorption near-edge structure spectra: a tool to push the limits of the X-ray absorption spectroscopy technique.

    PubMed

    D'Angelo, Paola; Migliorati, Valentina; Persson, Ingmar; Mancini, Giordano; Della Longa, Stefano

    2014-09-15

    A deconvolution procedure has been applied to K-edge X-ray absorption near-edge structure (XANES) spectra of lanthanoid-containing solid systems, namely, hexakis(dmpu)praseodymium(III) and -gadolinium(III) iodide. The K-edges of lanthanoids cover the energy range 38 (La)-65 (Lu) keV, and the large widths of the core-hole states lead to broadening of spectral features, reducing the content of structural information that can be extracted from the raw X-ray absorption spectra. Here, we demonstrate that deconvolution procedures allow one to remove most of the instrumental and core-hole lifetime broadening in the K-edge XANES spectra of lanthanoid compounds, highlighting structural features that are lost in the raw data. We show that quantitative analysis of the deconvolved K-edge XANES spectra can be profitably used to gain a complete local structural characterization of lanthanoid-containing systems not only for the nearest neighbor atoms but also for higher-distance coordination shells. PMID:25171598

  2. Robotic work station for microscale synthetic chemistry: On-line absorption spectroscopy, quantitative automated thin-layer chromatography, and multiple reactions in parallel

    NASA Astrophysics Data System (ADS)

    Lindsey, Jonathan S.; Corkan, L. Andrew; Erb, David; Powers, Gary J.

    1988-06-01

    A robotic work station has been constructed for automatically initiating and monitoring microscale chemical reactions. The work station consists of a robot with a general-purpose arm and interchangeable special-purpose hands, a carousel of seven reaction vessels, a series of stations for performing quantitative automated thin-layer chromatography (TLC), an on-line multichannel absorption spectrophotometer, sensors for verification, syringes and pumps for sample and solvent delivery, a supervisory computer for real-time data acquisition and process control, and a graphics terminal for data display. The controlling software is menu-driven and contains a scheduling algorithm that permits multiple reactions to be performed simultaneously. The automated TLC process is performed in four stages (plate dispensing, sample application, plate development, and plate densitometry), and samples are moved sequentially among these stations by the robot. The partial autonomy of these separate stations permits distributed sample processing. Four TLC plates are processed simultaneously with interleaving segmented schedules, giving a 160% increase in TLC sample throughput. The workstation can be applied to yield optimizations of synthetic reactions and to the exploration of synthetic reaction spaces. The capabilities of the workstation are demonstrated in the two-step synthesis of tetraphenylporphyrin from benzaldehyde and pyrrole in 1 h at room temperature. Kinetic data are obtained from a single-batch reaction concerning the consumption of benzaldehyde, the side reactions forming dipyrrylmethenes, and the formation of tetraphenylporphyrin.

  3. Entropy analysis of muscular near-infrared spectroscopy (NIRS) signals during exercise programme of type 2 diabetic patients: quantitative assessment of muscle metabolic pattern.

    PubMed

    Molinari, Filippo; Acharya, U Rajendra; Martis, Roshan Joy; De Luca, Riccardo; Petraroli, Giuliana; Liboni, William

    2013-12-01

    Diabetes mellitus (DM) is a metabolic disorder that is widely rampant throughout the world population these days. The uncontrolled DM may lead to complications of eye, heart, kidney and nerves. The most common type of diabetes is the type 2 diabetes or insulin-resistant DM. Near-infrared spectroscopy (NIRS) technology is widely used in non-invasive monitoring of physiological signals. Three types of NIRS signals are used in this work: (i) variation in the oxygenated haemoglobin (O2Hb) concentration, (ii) deoxygenated haemoglobin (HHb), and (iii) ratio of oxygenated over the sum of the oxygenated and deoxygenated haemoglobin which is defined as: tissue oxygenation index (TOI) to analyze the effect of exercise on diabetes subjects. The NIRS signal has the characteristics of non-linearity and non-stationarity. Hence, the very small changes in this time series can be efficiently extracted using higher order statistics (HOS) method. Hence, in this work, we have used sample and HOS entropies to analyze these NIRS signals. These computer aided techniques will assist the clinicians to diagnose and monitor the health accurately and easily without any inter or intra observer variability. Results showed that after a one-year of physical exercise programme, all diabetic subjects increased the sample entropy of the NIRS signals, thus revealing a better muscle performance and an improved recruitment by the central nervous system. Moreover, after one year of physical therapy, diabetic subjects showed a NIRS muscular metabolic pattern that was not distinguished from that of controls. We believe that sample and bispectral entropy analysis is need when the aim is to compare the inner structure of the NIRS signals during muscle contraction, particularly when dealing with neuromuscular impairments. PMID:24075080

  4. "EASY: A simple tool for simultaneously removing background, deadtime and acoustic ringing in quantitative NMR spectroscopy. Part II: Improved ringing suppression, application to quadrupolar nuclei, cross polarisation and 2D NMR".

    PubMed

    Jaeger, Christian; Hemmann, Felix

    2014-01-01

    A simple experiment for Elimination of Artifacts in NMR SpectroscopY (EASY) was introduced in Part I, and it was shown that NMR probe background signals, spectral distortions due to deadtime effects, and acoustic ringing can be eliminated simultaneously from solid-state NMR spectra. In this Part II, it is shown that acoustic ringing suppression can be improved up to one order of magnitude compared to the original EASY pulse sequence by inserting a delay ? between the two data acquisition scans of the EASY pulse sequence. The achievable ringing suppression depends on the length of this delay and is limited by the spin-lattice relaxation time T1. Furthermore, EASY is considered in conjunction with NMR of quadrupolar nuclei. For strong second-order broadening, EASY can be used to acquire either pure central transition MAS patterns or pure satellite transition NMR spectra. Two further modifications to EASY are introduced. One concerns improved ringing artifact suppression in experiments in which the central transition NMR signal is amplified by Rotor Assisted Population Transfer (RAPT). The second EASY modification enables the acquisition of quantitative NMR spectra if signals with different quadrupole coupling constants are present. In addition, acoustic ringing and (11)B stator signals are removed. Finally, it is demonstrated that the basic idea of EASY for removing ringing artifacts can be realized for heteronuclear one-dimensional and hetero- and homo-nuclear multi-dimensional NMR experiments using extended phase cycling. (15)N{(1)H} CPMAS and (15)N 2D Exchange NMR spectroscopy are considered as examples. PMID:25200102

  5. Quantitative analysis

    PubMed Central

    Nevin, John A.

    1984-01-01

    Quantitative analysis permits the isolation of invariant relations in the study of behavior. The parameters of these relations can serve as higher-order dependent variables in more extensive analyses. These points are illustrated by reference to quantitative descriptions of performance maintained by concurrent schedules, multiple schedules, and signal-detection procedures. Such quantitative descriptions of empirical data may be derived from mathematical theories, which in turn can lead to novel empirical analyses so long as their terms refer to behavioral and environmental events. Thus, quantitative analysis is an integral aspect of the experimental analysis of behavior. PMID:16812400

  6. Spectroscopy of divertor plasmas

    SciTech Connect

    Isler, R.C.

    1995-12-31

    The requirements for divertor spectroscopy are treated with respect to instrumentation and observations on present machines. Emphasis is placed on quantitative measurements.of impurity concentrations from the interpretation of spectral line intensities. The possible influence of non-Maxwellian electron distributions on spectral line excitation in the divertor is discussed. Finally the use of spectroscopy for determining plasma temperature, density, and flows is examined.

  7. In situ infrared emission spectroscopy for quantitative gas-phase measurement under high temperature reaction conditions: an analytical method for methane by means of an innovative small-volume flowing cell.

    PubMed

    Usseglio, Sandro; Thorshaug, Knut; Karlsson, Arne; Dahl, Ivar M; Nielsen, Claus J; Jens, Klaus-J; Tangstad, Elisabeth

    2010-02-01

    We have used infrared emission spectroscopy (IRES) in order to perform in situ studies under flowing gas-phase conditions. When the small-volume cell developed herein is used, we can (1) observe emission spectra from a hot gas-phase sample having an effective volume much less than one milliliter, (2) observe spectra of typical molecular species present, and (3) observe spectra of the more important molecular species down to below 10% and in some cases even as low as 1%. In addition, an analytical method has been derived in order to conduct quantitative studies under typical reaction conditions. We show that simplifications can be made in the data acquisition and handling for a direct linear correlation between band intensity and concentration with only simple background correction. The practical lower limit for methane in the present setup is approximately 0.5-1% v/v depending on the selected temperature. Our data were collected at 500, 600, and 700 degrees C, respectively. The major features of the present cell design are fairly simple and basically formed by a quartz tube (outer diameter=6 mm, inner diameter=4 mm) inside a metal pipe and two tubular ceramic heaters. This simple setup has advantages and attractive features that have extended the application of IRES to new fields and, in particular, for in situ studies of hydrocarbon reactions at different residence times at high temperature. PMID:20149274

  8. The use of multi-element aerosol particles for determining temporal variations in temperature and electron density in laser-induced plasmas in support of quantitative laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Asgill, Michael E.; Groh, Sebastian; Niemax, Kay; Hahn, David W.

    2015-07-01

    Quantitative laser-induced breakdown spectroscopy (LIBS) analysis operates on the assumption that the sample is completely dissociated and diffused within the highly energetic plasma on time-scales of analyte analysis, resulting in analyte emission ideally at the bulk plasma temperature and a signal that is linear with analyte mass concentration. However, recent studies focusing on aerosol analysis have found the heat and mass diffusion rates within laser-induced plasmas to be finite, resulting in particle-rich, locally perturbed areas within the hot bulk plasma. The goal of this study is to observe any related plasma differences, by calculating the bulk and local (i.e. analyte rich regions) plasma temperatures and electron density, to better understand the time frame of equilibrium between the local and bulk plasma properties. This study also seeks to determine whether the presence of large quantities of a matrix element can significantly alter the local plasma conditions, thereby generating matrix effects. We report the temporal profiles of particle-derived species, adding additional insight into the effect of local perturbation of plasma properties, with the conclusion that significant plasma residence (tens of microseconds) is necessary to minimize such effects.

  9. On Quantitizing

    PubMed Central

    Sandelowski, Margarete; Voils, Corrine I.; Knafl, George

    2009-01-01

    Quantitizing, commonly understood to refer to the numerical translation, transformation, or conversion of qualitative data, has become a staple of mixed methods research. Typically glossed are the foundational assumptions, judgments, and compromises involved in converting disparate data sets into each other and whether such conversions advance inquiry. Among these assumptions are that qualitative and quantitative data constitute two kinds of data, that quantitizing constitutes a unidirectional process essentially different from qualitizing, and that counting is an unambiguous process. Among the judgments are deciding what and how to count. Among the compromises are balancing numerical precision with narrative complexity. The standpoints of “conditional complementarity,” “critical remediation,” and “analytic alternation” clarify the added value of converting qualitative data into quantitative form. PMID:19865603

  10. Spectroscopy and chemistry of the atmosphere of Uranus

    NASA Technical Reports Server (NTRS)

    Fegley, Bruce, Jr.; Gautier, Daniel; Owen, Tobias; Prinn, Ronald G.

    1991-01-01

    A comprehensive review of the chemistry and spectroscopy of the Uranian atmosphere is presented by means of earth-based, earth-orbital, and Voyager 2 observations covering the UV, visible, infrared, and radio wavelength regions. It is inferred from these observations, in concert with the average density of about 1.3 g/cu cm, that the Uranian atmosphere is enriched in heavy elements relative to solar composition. Pre-Voyager earth-based observations of CH4 bands in the visible region and Voyager radio occultation data imply a CH4/H2 volume mixing ratio of about 2 percent corresponding to an enrichment of approximately 24 times the solar value of 0.000835. In contrast to CH4, microwave observations indicate an apparent depletion of NH3 in the 155-to-200-K region of the atmosphere by 100 to 200 times relative to the solar NH3/H2 mixing ratio of -0.000174. It is suggested that the temporal and latitudinal variations deduced for the NH3/H2 mixing ratio in this region of the Uranian atmosphere are due to atmospheric circulation effects.

  11. Ultraviolet Spectroscopy of Asteroid(4) Vesta

    NASA Technical Reports Server (NTRS)

    Li, Jian-Yang; Bodewits, Dennis; Feaga, Lori M.; Landsman, Wayne; A'Hearn, Michael F.; Mutchler, Max J.; Russell, Christopher T.; McFadden, Lucy A.; Raymond, Carol A.

    2011-01-01

    We report a comprehensive review of the UV-visible spectrum and rotational lightcurve of Vesta combining new observations by Hubble Space Telescope and Swift with archival International Ultraviolet Explorer observations. The geometric albedos of Vesta from 220 nm to 953 nm arc derived by carefully comparing these observations from various instruments at different times and observing geometries. Vesta has a rotationally averaged geometric albedo of 0.09 at 250 nm, 0.14 at 300 nm, 0.26 at 373 nm, 0.38 at 673 nm, and 0.30 at 950 nm. The linear spectral slope in the ultraviolet displays a sharp minimum ncar sub-Earth longitude of 20deg, and maximum in the eastern hemisphere. This is completely consistent with the distribution of the spectral slope in the visible wavelength. The uncertainty of the measurement in the ultraviolet is approx.20%, and in the visible wavelengths better than 10%. The amplitude of Vesta's rotational lightcurves is approx.10% throughout the range of wavelengths we observed, but is smaller at 950 nm (approx.6%) ncar the 1-micron mafic band center. Contrary to earlier reports, we found no evidence for any difference between the phasing of the ultraviolet and visible/ncar-infrared lightcurves with respect to sub-Earth longitude. Vesta's average spectrum between 220 and 950 nm can well be described by measured reflectance spectra of fine particle howardite-like materials of basaltic achondrite meteorites. Combining this with the in-phase behavior of the ultraviolet, visible. and ncar-infrared lightcurves, and the spectral slopes with respect to the rotational phase, we conclude that there is no global ultraviolet/visible reversal on Vesta. Consequently, this implies lack of global space weathering on Vesta. Keyword,: Asteroid Vesta; Spectrophotometry; Spectroscopy; Ultraviolet observations; Hubble Space Telescope observations

  12. Quantitative surface structure analysis by low-energy ion scattering

    Microsoft Academic Search

    M. Aono

    1984-01-01

    A review is presented of low-energy ion scattering spectroscopy (ISS) as a tool for surface atomic structure analysis. Especially, quantitative surface atomic structure analysis by ISS is highlighted. An important difference between ISS and Rutherford backscattering spectroscopy (RBS), a specialization of ISS for quantitative surface atomic structure analysis, and a general feature of the shadow cone in the energy range

  13. Attenuated total reflectance Fourier-transform infrared spectroscopy of carboxylic acids adsorbed onto mineral surfaces

    NASA Astrophysics Data System (ADS)

    Kubicki, J. D.; Schroeter, L. M.; Itoh, M. J.; Nguyen, B. N.; Apitz, S. E.

    1999-09-01

    A suite of naturally-occurring carboxylic acids (acetic, oxalic, citric, benzoic, salicylic and phthalic) and their corresponding sodium salts were adsorbed onto a set of common mineral substrates (quartz, albite, illite, kaolinite and montmorillonite) in batch slurry experiments. Solution pH's of approximately 3 and 6 were used to examine the effects of pH on sorption mechanisms. Attenuated total reflectance Fourier-transform infrared (ATR FTIR) spectroscopy was employed to obtain vibrational frequencies of the organic ligands on the mineral surfaces and in solution. UV/visible spectroscopy on supernatant solutions was also employed to confirm that adsorption from solution had taken place for benzoic, salicylic and phthalic acids. Molecular orbital calculations were used to model possible surface complexes and interpret the experimental spectra. In general, the tectosilicates, quartz and albite feldspar, did not chemisorb (i.e., strong, inner-sphere adsorption) the carboxylate anions in sufficient amounts to produce infrared spectra of the organics after rinsing in distilled water. The clays (illite, kaolinite and montmorillonite) each exhibited similar ATR FTIR spectra. However, the illite sample used in this study reacted to form strong surface and aqueous complexes with salicylic acid before being treated to remove free Fe-hydroxides. Chemisorption of carboxylic acids onto clays is shown to be limited without the presence of Fe-hydroxides within the clay matrix.

  14. Analysis of organic pollutant degradation in pulsed plasma by coherent anti-Stokes Raman spectroscopy

    SciTech Connect

    Bratescu, Maria Antoneta; Hieda, Junko; Umemura, Tomonari; Saito, Nagahiro; Takai, Osamu [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2011-05-15

    The degradation of p-benzoquinone (p-BQ) in water was investigated by the coherent anti-Stokes Raman spectroscopy (CARS) method, in which the change of the anti-Stokes signal intensity corresponding to the vibrational transitions of the molecule is monitored during and after solution plasma processing (SPP). In the beginning of SPP treatment, the CARS signal intensity of the ring vibrational molecular transitions at 1233 and 1660 cm{sup -1} increases under the influence of the electric field of the plasma, depending on the delay time between the plasma pulse and the laser firing pulse. At the same time, the plasma contributes to the degradation of p-BQ molecules by generating hydrogen and hydroxyl radicals, which decompose p-BQ into different carboxylic acids. After SPP, the CARS signal intensity of the vibrational bands of p-BQ ceased and the degradation of p-BQ was confirmed by UV-visible absorption spectroscopy and liquid chromatography analysis.

  15. Spectroscopy and kinetics of weakly bound gas phase adducts of atmospheric interest

    NASA Astrophysics Data System (ADS)

    Dookwah-Roberts, Venus

    A number of weakly bound adducts play important roles in atmospheric chemistry, such as DMS--OH and CS2--OH. The work comprising this dissertation involves kinetic and spectroscopic studies of adducts formed between halogen atoms and the important atmospheric trace gases CS2, CH3SCH3 (DMS), CH3I, and C2H 5I. The results reported in these studies are useful for developing an understanding of the reactivity of these species and for testing the ability of electronic structure theory and reaction rate theory to predict or rationalize any observed trends. Oxidative pathways of both alkyl halides and sulfur compounds, especially DMS, are of atmospheric interest based on the roles of these species in affecting the oxidizing capacity of the troposphere and in the formation of new particles which impact the Earth's radiation budget and climate variability. The experimental approach employed laser flash photolysis (LFP) coupled with time resolved UV-visible absorption spectroscopy (TRUVVAS) to investigate the spectroscopy and kinetics of the gas phase adducts: SCS--Cl, CH 3I--Cl, C2H5I--Cl, (CH3) 2S--Br, and (CH3)2S--I.

  16. Quantitative Analysen

    NASA Astrophysics Data System (ADS)

    Hübner, Philipp

    Der heilige Gral jeglicher Analytik ist, den wahren Wert bestimmen zu können. Dies bedingt quantitative Messmethoden, welche in der molekularen Analytik nun seit einiger Zeit zur Verfügung stehen. Das generelle Problem bei der Quantifizierung ist, dass wir meistens den wahren Wert weder kennen noch bestimmen können! Aus diesem Grund behelfen wir uns mit Annäherungen an den wahren Wert, indem wir aus Laborvergleichsuntersuchungen den Median oder den (robusten) Mittelwert berechnen oder indem wir einen Erwartungswert (expected value) aufgrund der Herstellung des Probenmaterials berechnen. Bei diesen Versuchen der Annäherung an den wahren Wert findet beabsichtigterweise eine Normierung der Analytik statt, entweder nach dem demokratischen Prinzip, dass die Mehrheit bestimmt oder durch zur Verfügungsstellung von geeignetem zertifiziertem Referenzmaterial. Wir müssen uns folglich bewusst sein, dass durch dieses Vorgehen zwar garantiert wird, dass die Mehrheit der Analysenlaboratorien gleich misst, wir jedoch dabei nicht wissen, ob alle gleich gut oder allenfalls gleich schlecht messen.

  17. Raman spectroscopy for noninvasive glucose measurements

    E-print Network

    Enejder, Annika M. K.

    We report the first successful study of the use of Raman spectroscopy for quantitative, noninvasive (“transcutaneous”) measurement of blood analytes, using glucose as an example. As an initial evaluation of the ability of ...

  18. Early detection of high-grade squamous intraepithelial lesions in the cervix with quantitative spectroscopic imaging

    E-print Network

    Lau, Condon

    Quantitative spectroscopy has recently been extended from a contact-probe to wide-area spectroscopic imaging to enable mapping of optical properties across a wide area of tissue. We train quantitative spectroscopic imaging ...

  19. Investigations of the electronic structure of d 0 transition metal oxides belonging to the perovskite family

    Microsoft Academic Search

    Hank W. Eng; Paris W. Barnes; Benjamin M. Auer; Patrick M. Woodward

    2003-01-01

    Computational and experimental studies using linear muffin tin orbital methods and UV-visible diffuse reflectance spectroscopy, respectively, were performed to quantitatively probe the relationships between composition, crystal structure and the electronic structure of oxides containing octahedrally coordinated d0 transition metal ions. The ions investigated in this study (Ti4+, Nb5+, Ta5+, Mo6+, and W6+) were examined primarily in perovskite and perovskite-related structures.

  20. Microwave Synthesis and Sintering of Bi4Ti3O12, the Aurivillius Compound: Structural and Chemical Effects of Attempted Lithiation

    Microsoft Academic Search

    S. KUMAR; M. PANNEERSELVAM; P. VINATIER; K. J. RAO

    2004-01-01

    Layered bismuth titanate, Bi4Ti3O12 (BTO) (Aurivillus phase) has been synthesized using microwave route. BTO has been prepared using conventional ceramic method also for comparison. Li intercalation into BTO has been attempted using a soft chemistry route. Inductively coupled plasma (ICP) has been used to estimate Li quantitatively and the lithiated sample is found to be Li2.38Bi4Ti3O12. Infrared and UV-visible spectroscopies

  1. Rapid biological synthesis of silver nanoparticles using plant leaf extracts

    Microsoft Academic Search

    Jae Yong Song; Beom Soo Kim

    2009-01-01

    Five plant leaf extracts (Pine, Persimmon, Ginkgo, Magnolia and Platanus) were used and compared for their extracellular synthesis\\u000a of metallic silver nanoparticles. Stable silver nanoparticles were formed by treating aqueous solution of AgNO3 with the plant leaf extracts as reducing agent of Ag+ to Ag0. UV-visible spectroscopy was used to monitor the quantitative formation of silver nanoparticles. Magnolia leaf broth

  2. Quarkonium spectroscopy

    SciTech Connect

    Scharre, D.L.

    1981-06-01

    Recent experimental investigations of heavy quark-antiquark bound state systems are reviewed. Results from SPEAR on charmonium spectroscopy and from DORIS and CESR on bottomonium spectroscopy are presented. The current status of the search for top is also discussed.

  3. BOOK REVIEW: Principles of Plasma Spectroscopy

    Microsoft Academic Search

    H. R. Griem

    1998-01-01

    This book gives a comprehensive treatment of plasma spectroscopy, the quantitative study of line and continuous radiation from high temperature plasmas. This highly interdisciplinary field combines elements of atomic, plasma and statistical physics, and has wide application to simulations and diagnostics of laboratory and astrophysical plasmas. Plasma spectroscopy is naturally intertwined with magnetic and inertial fusion energy science. Radiative processes

  4. Role of trimer-trimer interaction of bacteriorhodopsin studied by optical spectroscopy and high-speed atomic force microscopy.

    PubMed

    Yamashita, Hayato; Inoue, Keiichi; Shibata, Mikihiro; Uchihashi, Takayuki; Sasaki, Jun; Kandori, Hideki; Ando, Toshio

    2013-10-01

    Bacteriorhodopsin (bR) trimers form a two-dimensional hexagonal lattice in the purple membrane of Halobacterium salinarum. However, the physiological significance of forming the lattice has long been elusive. Here, we study this issue by comparing properties of assembled and non-assembled bR trimers using directed mutagenesis, high-speed atomic force microscopy (HS-AFM), optical spectroscopy, and a proton pumping assay. First, we show that the bonds formed between W12 and F135 amino acid residues are responsible for trimer-trimer association that leads to lattice assembly; the lattice is completely disrupted in both W12I and F135I mutants. HS-AFM imaging reveals that both crystallized D96N and non-crystallized D96N/W12I mutants undergo a large conformational change (i.e., outward E-F loop displacement) upon light-activation. However, lattice disruption significantly reduces the rate of conformational change under continuous light illumination. Nevertheless, the quantum yield of M-state formation, measured by low-temperature UV-visible spectroscopy, and proton pumping efficiency are unaffected by lattice disruption. From these results, we conclude that trimer-trimer association plays essential roles in providing bound retinal with an appropriate environment to maintain its full photo-reactivity and in maintaining the natural photo-reaction pathway. PMID:23462099

  5. Spectral methods for study of the G-protein-coupled receptor rhodopsin: I. Vibrational and electronic spectroscopy

    NASA Astrophysics Data System (ADS)

    Struts, A. V.; Barmasov, A. V.; Brown, M. F.

    2015-05-01

    Here we review the application of modern spectral methods for the study of G-protein-coupled receptors (GPCRs) using rhodopsin as a prototype. Because X-ray analysis gives us immobile snapshots of protein conformations, it is imperative to apply spectroscopic methods for elucidating their function: vibrational (Raman, FTIR), electronic (UV-visible absorption, fluorescence) spectroscopies, and magnetic resonance (electron paramagnetic resonance, EPR), and nuclear magnetic resonance (NMR). In the first of the two companion articles, we discuss the application of optical spectroscopy for studying rhodopsin in a membrane environment. Information is obtained regarding the time-ordered sequence of events in rhodopsin activation. Isomerization of the chromophore and deprotonation of the retinal Schiff base leads to a structural change of the protein involving the motion of helices H5 and H6 in a pH-dependent process. Information is obtained that is unavailable from X-ray crystallography, which can be combined with spectroscopic studies to achieve a more complete understanding of GPCR function.

  6. Time-resolved magnetic circular dichroism spectroscopy of photolyzed carbonmonoxy cytochrome c oxidase (cytochrome aa3).

    PubMed Central

    Goldbeck, R A; Dawes, T D; Einarsdóttir, O; Woodruff, W H; Kliger, D S

    1991-01-01

    Nanosecond time-resolved magnetic circular dichroism (TRMCD) and time-resolved natural circular dichroism (TRCD) measurements of photolysis products of the CO complex of eukaryotic cytochrome c oxidase (CcO-CO) are presented. TRMCD spectra obtained at 100 ns and 10 microseconds after photolysis are diagnostic of pentacoordinate cytochrome a3Fe2+, as would be expected for simple photodissociation. Other time-resolved spectroscopies (UV-visible and resonance Raman), however, show evidence for unusual Fea3(2+) coordination after CO photolysis (Woodruff, W. H., O. Einarsdóttir, R. B. Dyer, K. A. Bagley, G. Palmer, S. J. Atherton, R. A. Goldbeck, T. D. Dawes, and D. S. Kliger. 1991. Proc. Nat. Acad. Sci. U.S.A. 88:2588-2592). Furthermore, time-resolved IR experiments have shown that photodissociated CO binds to CuB+ prior to recombining with Fea3(2+) (Dyer, R. B., O. Einarsdóttir, P. M. Killough, J. J. López-Garriga, and W. H. Woodruff. 1989. J. Am. Chem. Soc. 111:7657-7659). A model of the CcO-CO photolysis cycle which is consistent with all of the spectroscopic results is presented. A novel feature of this model is the coordination of a ligand endogenous to the protein to the Fe axial site vacated by the photolyzed CO and the simultaneous breaking of the Fe-imidazole(histidine) bond. PMID:1653049

  7. Bimolecular photoinduced electron transfer reactions in liquids under the gaze of ultrafast spectroscopy.

    PubMed

    Rosspeintner, Arnulf; Vauthey, Eric

    2014-12-21

    Because of their key role in many areas of science and technology, bimolecular photoinduced electron transfer reactions have been intensively studied over the past five decades. Despite this, several important questions, such as the absence of the Marcus inverted region or the structure of the primary reaction product, have only recently been solved while others still remain unanswered. Ultrafast spectroscopy has proven to be extremely powerful to monitor the entire electron transfer process and to access, with the help of state-of-the-art theoretical models of diffusion-assisted reactions, crucial information like e.g. the intrinsic charge separation dynamics beyond the diffusion limit. Additionally, extension of these experimental techniques to other spectral regions than the UV-visible, such as the infrared, has given a totally new insight into the nature, the structure and the dynamics of the key reaction intermediates, like exciplexes and ions pairs. In this perspective, we highlight these recent progresses and discuss several aspects that still need to be addressed before a thorough understanding of these processes can be attained. PMID:25356933

  8. Evaluating aggregation of gold nanoparticles and humic substances using fluorescence spectroscopy.

    PubMed

    Pallem, Vasanta L; Stretz, Holly A; Wells, Martha J M

    2009-10-01

    The fate and transport of diagnostic gold nanoparticles in surface waters would significantly depend on their interactions with humic substances, which are ubiquitously found in natural aquatic systems. The current study employs UV-visible absorbance and fluorescence spectroscopy to investigate the interactions of commercial humic acid (HA) with gold nanoparticles having a core size of 5 nm and coated with two different stabilizers, beta-D-glucose and citrate. Humic substances (HS) are fluorescent in nature, providing a unique probe of nanometer-scale morphological changes for interactions between these natural polyelectrolytes and water-soluble gold nanoparticles. Quenching of fluorescence intensity was observed with beta-D-glucose-coated gold nanoparticles, whereas an enhancement effect was noticed with the citrate-coated particles when mixed with HA having concentrations of 2 and 8 ppm (surface waters typically may contain approximately 10 ppm HS). Examining the quenching and enhancement of fluorescence provides insight into the structural changes taking place at the coated gold nanoparticle-HA interface. The quenching behavior suggested ligand exchange due to nanometer-scale contact between the HA and beta-D-glucose-coated gold nanoparticles, whereas the enhancement effect with citrate particles would indicate overcoating, leading to increased transfer distances for fluorescence resonance energy transfer. PMID:19848172

  9. Raman spectroscopy of organic dyes adsorbed on pulsed laser deposited silver thin films

    NASA Astrophysics Data System (ADS)

    Fazio, E.; Neri, F.; Valenti, A.; Ossi, P. M.; Trusso, S.; Ponterio, R. C.

    2013-08-01

    The results of a surface-enhanced Raman scattering (SERS) study performed on representative organic and inorganic dyes adsorbed on silver nanostructured thin films are presented and discussed. Silver thin films were deposited on glass slides by focusing the beam from a KrF excimer laser (wavelength 248 nm, pulse duration 25 ns) on a silver target and performing the deposition in a controlled Ar atmosphere. Clear Raman spectra were acquired for dyes such as carmine lake, garanza lake and brazilwood overcoming their fluorescence and weak Raman scattering drawbacks. UV-visible absorption spectroscopy measurements were not able to discriminate among the different chromophores usually referred as carmine lake (carminic, kermesic and laccaic acid), as brazilwood (brazilin and brazilein) and as garanza lake (alizarin and purpurin). SERS measurements showed that the analyzed samples are composed of a mixture of different chromophores: brazilin and brazilein in brazilwood, kermesic and carminic acid in carmine lake, alizarin and purpurin in garanza lake. Detection at concentration level as low as 10-7 M in aqueous solutions was achieved. Higher Raman intensities were observed using the excitation line of 632.8 nm wavelength with respect to the 785 nm, probably due to a pre-resonant effect with the molecular electronic transitions of the dyes.

  10. Monitoring the in-situ oxide growth on uranium by ultraviolet-visible reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Schweke, Danielle; Maimon, Chen; Chernia, Zelig; Livneh, Tsachi

    2012-11-01

    We demonstrate the in-situ monitoring of oxide growth on U-0.1 wt. % Cr by means of UV-visible reflectance spectroscopy in the thickness range of ˜20-150 nm. Two different approaches are presented: In the "modeling approach," we employ a model for a metallic substrate covered by a dielectric layer, while taking into account the buildup of oxygen gradient and surface roughness. Then, we fit the simulated spectra to the experimental one. In the "extrema analysis," we derive an approximated analytical expression, which relates the oxide thickness to the position of the extrema in the reflectance spectra based on the condition for optical interference of the reflected light. Good agreement is found between the values extracted by the two procedures. Activation energy of ˜21 kcal/mole was obtained by monitoring the oxide growth in the temperature range of 22-90 °C. The upper bound for the thickness determination is argued to be mostly dictated by cracking and detachment processes in the formed oxide.

  11. Improved Algorithms for Accurate Retrieval of UV - Visible Diffuse Attenuation Coefficients in Optically Complex, Inshore Waters

    NASA Technical Reports Server (NTRS)

    Cao, Fang; Fichot, Cedric G.; Hooker, Stanford B.; Miller, William L.

    2014-01-01

    Photochemical processes driven by high-energy ultraviolet radiation (UVR) in inshore, estuarine, and coastal waters play an important role in global bio geochemical cycles and biological systems. A key to modeling photochemical processes in these optically complex waters is an accurate description of the vertical distribution of UVR in the water column which can be obtained using the diffuse attenuation coefficients of down welling irradiance (Kd()). The Sea UV Sea UVc algorithms (Fichot et al., 2008) can accurately retrieve Kd ( 320, 340, 380,412, 443 and 490 nm) in oceanic and coastal waters using multispectral remote sensing reflectances (Rrs(), Sea WiFS bands). However, SeaUVSeaUVc algorithms are currently not optimized for use in optically complex, inshore waters, where they tend to severely underestimate Kd(). Here, a new training data set of optical properties collected in optically complex, inshore waters was used to re-parameterize the published SeaUVSeaUVc algorithms, resulting in improved Kd() retrievals for turbid, estuarine waters. Although the updated SeaUVSeaUVc algorithms perform best in optically complex waters, the published SeaUVSeaUVc models still perform well in most coastal and oceanic waters. Therefore, we propose a composite set of SeaUVSeaUVc algorithms, optimized for Kd() retrieval in almost all marine systems, ranging from oceanic to inshore waters. The composite algorithm set can retrieve Kd from ocean color with good accuracy across this wide range of water types (e.g., within 13 mean relative error for Kd(340)). A validation step using three independent, in situ data sets indicates that the composite SeaUVSeaUVc can generate accurate Kd values from 320 490 nm using satellite imagery on a global scale. Taking advantage of the inherent benefits of our statistical methods, we pooled the validation data with the training set, obtaining an optimized composite model for estimating Kd() in UV wavelengths for almost all marine waters. This optimized composite set of SeaUVSeaUVc algorithms will provide the optical community with improved ability to quantify the role of solar UV radiation in photochemical and photobiological processes in the ocean.

  12. Controlled thin layer coating of carbon nanotube-polymer composites for UV-visible light protection

    Microsoft Academic Search

    Jaebeom Lee; Sang-Jun Park; Young-Kyun Moon; Soo-Hyung Kim; Kwangnak Koh

    2009-01-01

    A highly dispersed solution of multi-wall carbon nanotubes (MWCNT) and counterpart polymers was prepared in aqueous solution.\\u000a A thin layer coating was deposited on glass substrates by using the layer-by-layer (LBL) method. A negative charged dispersion\\u000a solution of MWCNT was obtained by oxidizing the MWCNT by immersion in nitric acid. Counterpart polymers, poly(diallydimethylammonium\\u000a chloride) (PDDA) and poly(acrylic acid) (PAA), were

  13. HST UV-Visible Observations of the Apollo 17 Landing Area

    Microsoft Academic Search

    M. S. Robinson; J. B. Garvin; B. Hapke; J. F. Bell III; M. Ulmer; D. Skillman; C. M. Pieters

    2006-01-01

    From Hubble Space Telescope (HST) Advanced Camera for Surveys High Resolution Camera (ACS\\/HRC) images we demonstrate the efficacy of UV imaging to map TiO2 abundances within mature regolith in the region of the Apollo 17 landing site.

  14. The Use of UV, Visible and Near IR Solar Back Scattered Radiation to Determine Trace Gases

    NASA Astrophysics Data System (ADS)

    Richter, Andreas; Wagner, Thomas

    Satellite remote sensing in the near-IR, visible and UV spectral range makes use of absorption and emission processes of electromagnetic radiation corresponding to electronic transitions, combined with simultaneous rotational-vibrational molecular transitions. One important difference compared to atmospheric observations in the microwave and thermal IR spectral range is that, usually thermal emission can be neglected at short wavelengths (there might, however, be emissions from, for example, excited gases in the high atmosphere). Thus the observed spectral signatures can be directly related to absorption spectra of atmospheric constituents. The neglect of emission terms makes the spectral analysis in the UV/vis spectral range usually reasonably straight forward. Another important and related advantage is that from satellite observations in the UV/vis spectral region, information from all atmospheric height layers (including the near surface layers) can be obtained. This makes UV/vis satellite observations a powerful tool for the monitoring of atmospheric pollution and for the characterisation and quantification of emission sources which are usually located close to the ground. It should, however, also be noted that, in contrast to observations in the microwave or thermal IR, usually little or no information on the vertical distribution of a trace gas is obtained.

  15. An Improved Flame Test for Qualitative Analysis Using a Multichannel UV-Visible Spectrophotometer

    ERIC Educational Resources Information Center

    Blitz, Jonathan P.; Sheeran, Daniel J.; Becker, Thomas L.

    2006-01-01

    Qualitative analysis schemes are used in undergraduate laboratory settings as a way to introduce equilibrium concepts and logical thinking. The main component of all qualitative analysis schemes is a flame test, as the color of light emitted from certain elements is distinctive and a flame photometer or spectrophotometer in each laboratory is…

  16. Compact and portable multiline UV & visible Raman lasers in hydrogen-filled HC-PCF

    Microsoft Academic Search

    Y. Y. Wang; F. Couny; P. S. Light; B. J. Mangan; F. Benabid

    2010-01-01

    We present two compact multi-line Raman-lasers based on two types of HC-PCF photonic microcells. Each discrete component of the laser exhibits high spectral power density and narrow linewidth for forensics and biomedical applications.

  17. Design of a broadband UV-visible alpha-barium borate polarizer.

    PubMed

    Appel, Roland; Dyer, Chris D; Lockwood, John N

    2002-05-01

    Until recently, the construction of polarizers for operation below approximately 260 nm were limited to materials such as magnesium fluoride and crystalline quartz. These materials have a much smaller birefringence than calcite, but unlike calcite they have good transmission below 200 nm. These materials are, however, not well suited for Glan-Taylor-type polarizer designs, as they do not produce a large angular separation of the polarized components. A new material, a-barium borate, has recently become available, which transmits to just below 200 nm and has a birefringence that approaches that of calcite. We analyze the performance of various polarizer designs that use this material. Results are presented that compare theory with experimental investigation of a manufactured device. PMID:12009158

  18. Broadband Lamp Standard For Ultraviolet (UV), Visible, And Infrared Calibration To 6.0 µm

    NASA Astrophysics Data System (ADS)

    Schneider, William E.; Goebel, David G.

    1982-03-01

    The new broadband spectral radiance standard consists of a specially modified tungsten ribbon-filament lamp with an optical grade, sapphire window. The lamp is calibrated for spectral radiance over the 0.25 to 6.0 ?m wavelength region. The standard serves as an accurate, convenient alternative to the much more costly high-temperature blackbody standard currently available.

  19. UV, VISIBLE AND NIR SPECTRAL ANALYSIS OF EGGSHELLS IN THE CHARADRIIDAE FAMILY OF BIRDS

    EPA Science Inventory

    We employed reflectance spectrophotometry to quantify color and mineral composition of eggshells from several species of the bird family Charadriidae to characterize species physiology and to distinguish nesting habitat preferences. We used a Shimadzu spectrophotometer to measur...

  20. Ablation of ceramics by UV, visible, and IR pulsed laser radiation

    NASA Astrophysics Data System (ADS)

    Konov, Vitali I.; Dausinger, Friedrich; Garnov, Serge V.; Klimentov, Sergei M.; Kononenko, Taras V.; Tsarkova, O. G.

    1997-05-01

    Multiparametric study of A1N ceramic ablation by high intensity (I less than or equal to 1013 W/cm2) nano and picosecond pulses of Nd:YAP laser have been performed. Ablation rates, surface morphology and element content, reflectivity and absorptivity of ceramic plates prior and after pulsed irradiation as well as high temperature material reflectivity have been measured. It is shown that high etch rate and good quality A1N ceramic microstructuring (cutting, hole drilling, pocket formation) can be obtained for the first, second and fourth laser harmonics if irradiation conditions are properly chosen. It was found that possibility to effectively process material, which initially weakly absorbs laser beam (first and second harmonic), it is determined by radiation and plasma induced surface modification. Comparison with other types of ceramics, such as Al2O3, Si3N4, SiC, is also made.

  1. First Results On The Imaging Capabilities Of A DROID Array In The UV/Visible

    SciTech Connect

    Hijmering, R. A.; Verhoeve, P.; Martin, D. D. E. [Advanced Studies and Technology Preparation Division, Directorate of Science and Robotic Exploration of the European Space Agency, ESTEC, P.O. Box 299, 2200 AG Noordwijk (Netherlands); Venn, R. [Cambridge Microfab ltd, Broadway, Bourn, CB3 7TA (United Kingdom)

    2009-12-16

    Within the SCAM project of the European Space Agency the next step in the development of a cryogenic optical photon counting imaging spectrometer would be to increase the field of view using DROIDs (Distributed Read-Out Imaging Detector). We present the results of the first system test using an array of 60 360x33.5 {mu}m{sup 2} DROIDs in a 3x20 format for optical photon detection. This is an increase in area by a factor of 5.5 compared to the successful S-Cam 3 detector. The responsivity of the DROID array tested is too low for actual use on the telescope. However the spatial resolution of {approx}35 {mu}m is just above the size of a virtual pixel and imaging capabilities of the array can be demonstrated. With increasing responsivity this will improve, yielding a DROID array which can be used as an astronomical optical photon counting imaging spectrometer.

  2. NEW TECHNOLOGY Role of Frequency Domain Optical Spectroscopy

    E-print Network

    Fantini, Sergio

    ISS Inc., Champaign, Illinois Objective: Inability of continuous wave (CW) optical spectroscopyNEW TECHNOLOGY Role of Frequency Domain Optical Spectroscopy in the Detection of Neonatal Brain objective was to assess whether, and to what extent, the use of quantitative frequency domain spectroscopy

  3. Quantitation of carcinogen bound protein adducts by fluorescence measurements

    NASA Astrophysics Data System (ADS)

    Gan, Liang-Shang; Otteson, Michael S.; Doxtader, Mark M.; Skipper, Paul L.; Dasari, Ramachandra R.; Tannenbaum, Steven R.

    1989-01-01

    A highly significant correlation of aflatoxin B 1 serum albumin adduct level with daily aflatoxin B 1 intake was observed in a molecular epidemiological study of aflatoxin carcinogenesis which used conventional fluorescence spectroscopy methods for adduct quantitation. Synchronous fluorescence spectroscopy and laser induced fluorescence techniques have been employed to quantitate antibenzo[ a]pyrene diol epoxide derived globin peptide adducts. Fast and efficient methods to isolate the peptide adducts as well as eliminate protein fluorescence background are described. A detection limit of several femtomoles has been achieved. Experimental and technical considerations of low temperature synchronous fluorescence spectroscopy and fluorescence line narrowing to improve the detection sensitivities are also presented.

  4. Digital PCR and Quantitation

    E-print Network

    Perkins, Richard A.

    Applied Genetics Digital PCR and Quantitation Ross Haynes Research Biologist, Applied Genetics Group Forensics@NIST 2012 Meeting Gaithersburg, MD November 28, 2012 #12;Applied Genetics Agenda · Why quantitate with qPCR? · How digital PCR Will Help Quantitation · Quantitative PCR versus Digital PCR

  5. Quantitative Mineralogical Characterization of Oregon Erionite

    NASA Astrophysics Data System (ADS)

    Dogan, A.; Dogan, M.; Ballirano, P.

    2006-12-01

    Erionite has been classified as Group-I Human Carcinogen by the IARC Working Group. Fibrogenetic potential of erionite varies from low to high yield of mesothelioma. This may require quantitative characterization of physicochemical properties of erionite before any experimental design. The toxicity of the mineral is such that quantitative characterization of erionite is extremely important. Yet, often the erionite specimens were incompletely or incorrectly characterized throwing doubt on the results of the work. For example, none of the Turkish erionite published until recently had balance error (E%) less than 10%, and Mg cation of the type specimen of erionite-Ca from Maze, Niigita Prefecture, Japan is more than 0.8. In the present study, erionite sample near Rome, Oregon have been quantitatively characterized using powder x-ray diffraction, Reitveld refinement, scanning electron microscopy, energy dispersive spectroscopy, inductively coupled plasma - mass spectroscopy, and Massbauer spectroscopy. The cell parameters of the erionite-K from Oregon is computed as a=13.2217(2) Å and c=15.0671 Å; chemical composition of the erionite as major oxides, rare earth elements and other trace elements, are characterized quantitatively. Crystal chemistries of the erionite are computed based upon the quidelines of the IMAA zeolite report of 1997.

  6. Identification of different species of Bacillus isolated from Nisargruna Biogas Plant by FTIR, UV-Vis and NIR spectroscopy.

    PubMed

    Ghosh, S B; Bhattacharya, K; Nayak, S; Mukherjee, P; Salaskar, D; Kale, S P

    2015-09-01

    Definitive identification of microorganisms, including pathogenic and non-pathogenic bacteria, is extremely important for a wide variety of applications including food safety, environmental studies, bio-terrorism threats, microbial forensics, criminal investigations and above all disease diagnosis. Although extremely powerful techniques such as those based on PCR and microarrays exist, they require sophisticated laboratory facilities along with elaborate sample preparation by trained researchers. Among different spectroscopic techniques, FTIR was used in the 1980s and 90s for bacterial identification. In the present study five species of Bacillus were isolated from the aerobic predigester chamber of Nisargruna Biogas Plant (NBP) and were identified to the species level by biochemical and molecular biological (16S ribosomal DNA sequence) methods. Those organisms were further checked by solid state spectroscopic absorbance measurements using a wide range of electromagnetic radiation (wavelength 200nm to 25,000nm) encompassing UV, visible, near Infrared and Infrared regions. UV-Vis and NIR spectroscopy was performed on dried bacterial cell suspension on silicon wafer in specular mode while FTIR was performed on KBr pellets containing the bacterial cells. Consistent and reproducible species specific spectra were obtained and sensitivity up to a level of 1000 cells was observed in FTIR with a DTGS detector. This clearly shows the potential of solid state spectroscopic techniques for simple, easy to implement, reliable and sensitive detection of bacteria from environmental samples. PMID:25930088

  7. IR Spectroscopy

    NSDL National Science Digital Library

    Reich, Ieva

    These organic chemistry quiz questions from the JCE question bank focus on the topic of Infrared Spectroscopy. Students can use these as review material or to prepare for exams. Answer keys are made available to teachers for a small fee.

  8. Amateur Spectroscopy

    NSDL National Science Digital Library

    The main objective of this website is to teach the amateur astronomer how to perform spectroscopy. The first part of the website is dedicated to establishing a theoretical foundation, in which the process of spectroscopy is explained: how spectral lines are created, the operation of a spectroscope, and grating spectroscopy. Later on, all these concepts are applied to astronomy, specifically to stars. Using spectroscopy, astronomers are able to identify the composition of stars, which leads to a classification catalog dependent on the spectral lines observed. Several spectra, from different objects like supernovae and stars are presented for the user to observe, along with distinctive spectral lines from some chemical elements. Finally, this website motivates amateurs by suggesting several project ideas along with a list of references and instrument suppliers.

  9. Quantitative measurement of cyanide species in simulated ferrocyanide Hanford waste

    SciTech Connect

    Bryan, S.A.; Pool, K.H.; Matheson, J.D.

    1993-02-01

    Analytical methods for the quantification of cyanide species in Hanford simulated high-level radioactive waste were pursued in this work. Methods studied include infrared spectroscopy (solid state and solution), Raman spectroscopy, Moessbauer spectroscopy, X-ray diffraction, scanning electron microscopy-electron dispersive spectroscopy (SEM-EDS), and ion chromatography. Of these, infrared, Raman, X-ray diffraction, and ion chromatography techniques show promise in the concentration range of interest. Quantitation limits for these latter four techniques were demonstrated to be approximately 0.1 wt% (as cyanide) using simulated Hanford wastes.

  10. Laser-induced plasma spectroscopy: principles, methods and applications

    SciTech Connect

    Lazic, Violeta; Colao, Francesco; Fantoni, Roberta; Spizzichino, Valeria [ENEA, FIS-LAS, V. E. Fermi 45, Frascati (RM) (Italy); Jovicevic, Sonja [Institute of Physics, 11080 Belgrade, Pregrevica 118 (Serbia and Montenegro)

    2006-12-01

    Principles of the Laser Induced Plasma Spectroscopy and its advances are reported. Methods for obtaining quantitative analyses are described, together with discussion of some applications and the specific problems.

  11. Infrared Spectroscopy

    NSDL National Science Digital Library

    C. P. Sherman Hsu

    This 38-page PDF document is a chapter from the Handbook of Instrumental Techniques for Analytical Chemistry. The chapter explains how infrared spectroscopy works (no comma) along with its general uses, common applications, range and limitations. Also included are spectrometer designs, information about sample preparation, analytical methods, related methods such as gas chromotography and diffuse reflectance, and costs and instrument vendors.

  12. Treatment assessment of radiotherapy using MR functional quantitative imaging

    PubMed Central

    Chang, Zheng; Wang, Chunhao

    2015-01-01

    Recent developments in magnetic resonance (MR) functional quantitative imaging have made it a potentially powerful tool to assess treatment response in radiation therapy. With its abilities to capture functional information on underlying tissue characteristics, MR functional quantitative imaging can be valuable in assessing treatment response and as such to optimize therapeutic outcome. Various MR quantitative imaging techniques, including diffusion weighted imaging, diffusion tensor imaging, MR spectroscopy and dynamic contrast enhanced imaging, have been investigated and found useful for assessment of radiotherapy. However, various aspects including data reproducibility, interpretation of biomarkers, image quality and data analysis impose challenges on applications of MR functional quantitative imaging in radiotherapy assessment. All of these challenging issues shall be addressed to help us understand whether MR functional quantitative imaging is truly beneficial and contributes to future development of radiotherapy. It is evident that individualized therapy is the future direction of patient care. MR functional quantitative imaging might serves as an indispensable tool towards this promising direction. PMID:25628799

  13. Quantitative Measurements of HO2 and other products of n-butane oxidation (H2O2, H2O, CH2O, and C2H4) at elevated temperatures by direct coupling of a jet-stirred reactor with sampling nozzle and cavity ring-down spectroscopy (cw-CRDS).

    PubMed

    Djehiche, Mokhtar; Le Tan, Ngoc Linh; Jain, Chaithanya D; Dayma, Guillaume; Dagaut, Philippe; Chauveau, Christian; Pillier, Laure; Tomas, Alexandre

    2014-11-26

    For the first time quantitative measurements of the hydroperoxyl radical (HO2) in a jet-stirred reactor were performed thanks to a new experimental setup involving fast sampling and near-infrared cavity ring-down spectroscopy at low pressure. The experiments were performed at atmospheric pressure and over a range of temperatures (550-900 K) with n-butane, the simplest hydrocarbon fuel exhibiting cool flame oxidation chemistry which represents a key process for the auto-ignition in internal combustion engines. The same technique was also used to measure H2O2, H2O, CH2O, and C2H4 under the same conditions. This new setup brings new scientific horizons for characterizing complex reactive systems at elevated temperatures. Measuring HO2 formation from hydrocarbon oxidation is extremely important in determining the propensity of a fuel to follow chain-termination pathways from R + O2 compared to chain branching (leading to OH), helping to constrain and better validate detailed chemical kinetics models. PMID:25381864

  14. Quantitative spectroscopic imaging for noninvasive early cancer detection

    PubMed Central

    Yu, Chung-Chieh; Lau, Condon; O’Donoghue, Geoff; Mirkovic, Jelena; McGee, Sasha; Galindo, Luis; Elackattu, Alphi; Stier, Elizabeth; Grillone, Gregory; Badizadegan, Kamran; Dasari, Ramachandra R.; Feld, Michael S.

    2008-01-01

    We report a fully quantitative spectroscopy imaging instrument for wide area detection of early cancer (dysplasia). This instrument provides quantitative maps of tissue biochemistry and morphology, making it a potentially powerful surveillance tool for objective early cancer detection. We describe the design, construction, calibration, and first clinical application of this new system. We demonstrate its accuracy using physical tissue models. We validate its diagnostic ability on a resected colon adenoma, and demonstrate feasibility of in vivo imaging in the oral cavity. PMID:18825262

  15. Development of fiber optic sensor based on laser Raman spectroscopy

    Microsoft Academic Search

    Vidhu Shekhar Tiwari

    2008-01-01

    Laser Raman Spectroscopy (LRS) has received worldwide acknowledgement as a powerful molecular 'finger print' technique. The Raman spectrum of sample contains useful information such as molecular identity, composition, constituent's concentration ratio etc. These information are manifested in the Raman spectrum in band heights, peak wavelength, band areas etc. The basis of quantitative analysis in Raman spectroscopy lies in the measurement

  16. Diffuse reflectance spectroscopy of fibrous proteins.

    PubMed

    Millington, Keith R

    2012-09-01

    UV-visible diffuse reflectance (DR) spectra of the fibrous proteins wool and feather keratin, silk fibroin and bovine skin collagen are presented. Natural wool contains much higher levels of visible chromophores across the whole visible range (700-400 nm) than the other proteins and only those above 450 nm are effectively removed by bleaching. Both oxidative and reductive bleaching are inefficient for removing yellow chromophores (450-400 nm absorbers) from wool. The DR spectra of the four UV-absorbing amino acids tryptophan, tyrosine, cystine and phenylalanine were recorded as finely ground powders. In contrast to their UV-visible spectra in aqueous solution where tryptophan and tyrosine are the major UV absorbing species, surprisingly the disulphide chromophore of solid cystine has the strongest UV absorbance measured using the DR remission function F(R)(?). The DR spectra of unpigmented feather and wool keratin appear to be dominated by cystine absorption near 290 nm, whereas silk fibroin appears similar to tyrosine. Because cystine has a flat reflectance spectrum in the visible region from 700 to 400 nm and the powder therefore appears white, cystine absorption does not contribute to the cream colour of wool despite the high concentration of cystine residues near the cuticle surface. The disulphide absorption of solid L: -cystine in the DR spectrum at 290 nm is significantly red shifted by ~40 nm relative to its wavelength in solution, whereas homocystine and lipoic acid showed smaller red shifts of 20 nm. The large red shift observed for cystine and the large difference in intensity of absorption in its UV-visible and DR spectra may be due to differences in the dihedral angle between the crystalline solid and the solvated molecules in solution. PMID:22218994

  17. Electronic spectroscopies

    Microsoft Academic Search

    B. M. Weckhuysen; R. A. Schoonheydt

    2000-01-01

    Diffuse reflectance spectroscopy (DRS) in the ultraviolet, visible and near-infrared\\u000aregion is a versatile spectroscopic technique, as both d-d and charge transfer\\u000atransitions of supported TMI can be probed. One of the advantages of electronic\\u000aspectroscopy is that the obtained information is directly chemical since the outer shell\\u000aelectrons of the TMI are probed and provide information about the oxidation

  18. Impedance spectroscopy

    Microsoft Academic Search

    J. Ross Macdonald

    1992-01-01

    Impedance spectroscopy (IS) is a general term that subsumes the small-signal measurement of the linear electrical response\\u000a of a material of interest (including electrode effects) and the subsequent analysis of the response to yield useful information\\u000a about the physicochemical properties of the system. Analysis is generally carried out in the frequency domain, although measurements\\u000a are sometimes made in the time

  19. Investigation of the azo-hydrazone tautomeric equilibrium in an azo dye involving the naphthalene moiety by UV-vis spectroscopy and quantum chemistry

    NASA Astrophysics Data System (ADS)

    Ünal, Arslan; Eren, Bilge; Eren, Erdal

    2013-10-01

    Photophysical properties of the azo-hydrazone tautomerism of Eriochrome Blue Black B (1-(1-hydroxy-2-naphthylazo)-2-naphthol-4-sulphonic acid) in DMF, MeCN and water were investigated using UV-visible spectroscopy and quantum chemical calculations. The optimized molecular structure parameters, relative energies, mole fractions, electronic absorption spectra and HOMO-LUMO energies for possible stable tautomeric forms of EBB were theoretically calculated by using hybrid density functional theory, (B3LYP) methods with 6-31G(d) basis set level and polarizable continuum model (PCM) for solvation effect. The effects of varying pH-, dye concentration-, solvent-, temperature-, and time-dependences on the UV-vis spectra of Eriochrome Blue Black B were also investigated experimentally. The calculations showed that the dye exhibited acid-base, azo-hydrazone and aggregate equilibria in DMF solution, while the most probably preferred form in MeCN solution was azo form. Thermodynamic parameters of dimerization reaction in DMF solution proved that entropy was the driving force of this reaction.

  20. Femtosecond polarization resolved spectroscopy: A tool for determination of the three-dimensional orientation of electronic transition dipole moments and identification of configurational isomers

    NASA Astrophysics Data System (ADS)

    Theisen, Moritz; Linke, Martin; Kerbs, Max; Fidder, Henk; Madjet, Mohamed El-Amine; Zacarias, Angelica; Heyne, Karsten

    2009-09-01

    A method is presented that combines femtosecond polarization resolved UV/visible pump-IR probe spectroscopy and density functional theory calculations in determining the three-dimensional orientation of an electronic transition dipole moment (tdm) within the molecular structure. The method is demonstrated on the approximately planar molecule coumarin 314 (C314) dissolved in acetonitrile, which can exist in two ground state configurations: the E- and the Z-isomer. Based on an exhaustive search analysis on polarization resolved measurement data for four different vibrational modes, it is concluded that C314 in acetonitrile is the E-isomer. The electronic tdm vector for the electronic S0?S1 transition is determined and the analysis shows that performing the procedure for four vibrational modes instead of the minimally required three reduces the 1? probability area from 2.34% to 2.24% of the solution space. Moreover, the fastest rotational correlation time ?c for the C314 E-isomer is determined to be 26±2 ps.

  1. Charge Photoinjection in Intercalated and Covalently Bound [Re(CO)3(dppz)(py)]+-DNA Constructs Monitored by Time Resolved Visible and Infrared Spectroscopy

    PubMed Central

    Olmon, Eric D.; Sontz, Pamela A.; Blanco-Rodríguez, Ana María; Towrie, Michael; Clark, Ian P.; Vl?ek, Antonín; Barton, Jacqueline K.

    2011-01-01

    The complex [Re(CO)3(dppz)(py?-OR)]+ (dppz = dipyrido[3,2-a:2?,3?-c]phenazine; py?-OR = 4-functionalized pyridine) offers IR sensitivity and can oxidize DNA directly from the excited state, making it a promising probe for the study of DNA-mediated charge transport (CT). The behavior of several covalent and noncovalent Re-DNA constructs was monitored by time-resolved IR (TRIR) and UV/visible spectroscopies, as well as biochemical methods, confirming the long-range oxidation of DNA by the excited complex. Optical excitation of the complex leads to population of MLCT and at least two distinct intraligand states. Experimental observations that are consistent with charge injection from these excited states include similarity between long-time TRIR spectra and the reduced state spectrum observed by spectroelectrochemistry, the appearance of a guanine radical signal in TRIR spectra, and the eventual formation of permanent guanine oxidation products. The majority of reactivity occurs on the ultrafast timescale, although processes dependent on slower conformational motions of DNA, such as the accumulation of oxidative damage at guanine, are also observed. The ability to measure events on such disparate timescales, its superior selectivity in comparison to other spectroscopic techniques, and the ability to simultaneously monitor carbonyl ligand and DNA IR absorption bands makes TRIR a valuable tool for the study of CT in DNA. PMID:21827149

  2. Surface analysis with Auger electron spectroscopy

    NASA Astrophysics Data System (ADS)

    Grant, J. T.

    Experimental aspects of Auger electron spectroscopy (AES) as applied to solid surfaces are reviewed. Areas considered include instrumentation, methods of excitation, acquisition of spectra, chemical effects, quantitative analysis, depth profiling and mapping. This review is designed to give the reader a comprehensive view of experimental aspects of AES with suitable references for more detailed information.

  3. Zirconium titanate ceramic pigments: Crystal structure, optical spectroscopy and technological properties

    SciTech Connect

    Dondi, M. [Institute of Science and Technology for Ceramics (ISTEC-CNR), Via Granarolo 64, 48018 Faenza (Italy); Matteucci, F. [Institute of Science and Technology for Ceramics (ISTEC-CNR), Via Granarolo 64, 48018 Faenza (Italy)]. E-mail: matteucci@istec.cnr.it; Cruciani, G. [Department of Earth Sciences, Via Saragat 1, University of Ferrara, 44100 Ferrara (Italy)

    2006-01-15

    Srilankite-type zirconium titanate, a promising structure for ceramic pigments, was synthesized at 1400 deg. C following three main doping strategies: (a) ZrTi{sub 1-x}A{sub x}O{sub 4} (b) ZrTi{sub 1-x-y}A{sub x}B{sub y}O{sub 4} and (c) Zr{sub 1-x}C{sub x}TiO{sub 4} where A=Co, Cr, Fe, Mn, Ni or V (chromophores), B=Sb or W (counterions) and C=Pr (chromophore); x=y=0.05. Powders were characterized by XRD with Rietveld refinements and DRS in the UV-visible-NIR range; technological properties were appraised in several ceramic matrices (frits, glazes and body). Zirconium titanate can be usefully coloured with first row transition elements, giving green and greenish yellow (Co and Ni); orange-buff (Cr and V); tan-brown hues (Mn and Fe). In industrial-like synthesis conditions, a disordered structure as (Zr,Ti)O{sub 2}, with both Zr and Ti randomly distributed in the octahedral site, is achieved. Doping with chromophores and counterions induces unit cell dimensions variation and causes an oversaturation in zirconium oxide. Optical spectroscopy reveals the occurrence of Co{sup 2+}, Cr{sup 3+}, Fe{sup 3+}, Mn{sup 2+}, Mn{sup 3+}, Ni{sup 2+}, V{sup 3+} and V{sup 4+}. The zirconium titanate pigments fulfil current technological requirements for low-temperature applications, but exhibit a limited chemico-physical stability for higher firing temperature and in chemically aggressive media.

  4. Absorption spectroscopy of RDX monopropellant flames: CN and NH concentrations

    NASA Astrophysics Data System (ADS)

    Homan, B. E.; Vanderhoff, John A.

    1997-11-01

    UV-visible multi-channel absorption spectroscopy has been used to probe the self-sustained combustion of pressed RDX, a main energetic ingredient found in modern day propellants and explosives. The two dimensional feature of an intensified CCD detector allowed simultaneous recording of multiple, spatially distinct absorption spectra. Between 10 and 12 equally spaced absorption spectra with spatial resolution as small as 0.163 mm have been obtained during 1 ms exposure. The number of absorption spectra and the spatial resolution can easily be set by the detector software, size of the excitation sheet and the focal length of the collection lens. Temporal resolution in the UV region has been increased to 1 ms by pulsing the light source. A 0.54 joule pulse with a duration of 0.75 ms was added to a simmering Xenon arc lamp for the measurement of combustion species. The increase in light intensity of 30 and 70 times the non-pulsed output provided the necessary light flux to achieve single pulse, multiple absorption spectra. To increase the species concentration sensitivity of the experiment, a triple pass optical arrangement was adopted. Partially silvered windows were installed at an angle to the beam providing for three passes across the samples. The corresponding path length was increased by a factor of 2.8 times the sample diameter. Least squares analysis of absorption spectra provide mole fraction profiles for OH, CN and NH along with temperature. Profiles for NC and HN have been determined for self-sustained combustion of RDX in 1.0, 1.5 and 2.0 atm air. Peak CN mole fractions of about 200 ppm are observed at 1 atm pressure and the NH mole fraction is about a factor of two lower. As the pressure is increased the reactive CN and HN species peak closer to the combusting surface and reside over a smaller spatial extent. Peak concentrations drop for these higher pressures, but may be due, at least in part, to limitations of the spatial resolution of the absorption experiment.

  5. Laser Spectroscopy

    NASA Astrophysics Data System (ADS)

    Katori, H.; Yoneda, H.; Nakagawa, K.; Shimizu, F.

    2010-02-01

    Anderson localization of matter-waves in a controlled disorder: a quantum simulator? / A. Aspect ... [et al.] -- Squeezing and entanglement in a Bose-Einstein condensate / C. Gross ... [et al.] -- New physics in dipolar Bose-Einstein condensates / Y. Kawaguchi, H. Saito, and M. Ueda -- Observation of vacuum fluctuations in a spinor Bose-Einstein condensate / C. Klempt ... [et al.] -- Negative-index media for matter waves / F. Perales ... [et al.] -- Entanglement of two individual atoms using the Rydberg blockade / A. Browaeys ... [et al.] -- Array of mesoscopic ensembles on a magnetic atom chip / A. F. Tauschinsky ... [et al.] -- Stability of the proton-to-electron mass ratio tested with molecules using an optical link to primary clock / A. Amy-Klein ... [et al.] -- Metastable helium: lifetime measurements using cold atoms as a test of QED / K. G. H. Baldwin ... [et al.] -- Optical lattice clocks with single occupancy bosons and spin-polarized fermions toward 10[symbol] accuracy / M. Takamoto ... [et al.] -- Frequency measurements of Al[symbol] and Hg[symbol] optical standards / W. M. Itano ... [et al.] -- Switching of light with light using cold atoms inside a hollow optical fiber / M. Bajcsy ... [et al.] -- Room-temperature atomic ensembles for quantum memory and magnetometry / K. Jensen ... [et al.] -- Components for multi-photon non-classical state preparation and measurement / G. Puentes ... [et al.] -- Quantum field state measurement and reconstruction in a cavity by quantum nondemolition photon counting / M. Brune ... [et al.] -- XUV frequency comb spectroscopy / C. Gohle ... [et al.] -- Ultrahigh-repetition-rate pulse train with absolute-phase control produced by an adiabatic raman process / M. Katsuragawa ... [et al.] -- Strongly correlated bosons and fermions in optical lattices / S. Will ... [et al.] -- Bragg spectroscopy of ultracold bose gases in optical lattices / L. Fallani ... [et al.] -- Synthetic quantum many-body systems / C. Guerlin ... [et al.] -- Ultracold Ytterbium atoms in optical lattices / S. Sugawa ... [et al.] -- Ultracold polar molecules in the rovibrational ground state / J. Deiglmayr ... [et al.] -- Polar molecules near quantum degeneracy / J. Ye and D. S. Jin -- Production of a quantum gas of rovibronic ground-state molecules in an optical lattice / J. G. Danzl ... [et al.] -- Recent progress in x-ray nonlinear optics / K. Tamasaku, K. Sawada, and T. Ishikawa -- Gas in scattering media absorption spectroscopy - laser spectroscopy in unconventional environments / S. Svanberg -- Laser spectroscopy on relativistic ion beams / S. Reinhardt ... [et al.] -- Single frequency microcavity lasers and applications / L. Xu ... [et al.].

  6. Electrosynthesis of ZnO nanorods and nanotowers: Morphology and X-ray Absorption Near Edge Spectroscopy studies

    NASA Astrophysics Data System (ADS)

    Sigircik, Gokmen; Erken, Ozge; Tuken, Tunc; Gumus, Cebrail; Ozkendir, Osman M.; Ufuktepe, Yuksel

    2015-06-01

    Deposition mechanism of nano-structured ZnO films has been investigated in the absence and presence of chloride ions from aqueous solution. The resulting opto-electronic properties were interpreted extensively, using X-ray diffraction (XRD), X-ray Absorption Near Edge Spectroscopy (XANES), field emission scanning electron microscopy (FE-SEM), UV-Visible spectroscopy and four probe techniques. The ZnO deposition is mass transport controlled process and the interaction of chloride ions with the surface has great influence on diffusion kinetics, considering the substantial species (Zn2+ and OH-) involved in the construction of ZnO film. This effect does not change major lattice parameters, as shown with detailed analysis of XRD data. However, the texture coefficient (Tc) (0 0 2) value is higher in presence of chloride ions containing synthesis solution which gave vertically aligned, well defined and uniformly dispersed nanorods structure. The calculated Eg values are in the range 3.28-3.41 eV and 3.22-3.31 eV for ZnO nanorods and nanotowers synthesized at different deposition periods, respectively. Furthermore, the charge mobility values regarding the deposition periods were measured to be in the ranges from 130.4 to 449.2 cm2 V-1 s-1 and 126.2 to 204.7 cm2 V-1 s-1 for nanorods and nanotowers, respectively. From XANES results, it was shown that the Zn K-edge spectrum is dominated by the transition of Zn 1s core electrons into the unoccupied Zn 4p states of the conduction band. Comparing the rod and tower nano-structured ZnO thin films, the excitation behavior of valence band electrons is different. Moreover, the density states of Zn 4p are higher for ZnO nanorods.

  7. Soft x-ray spectroscopy studies of novel electronic materials using synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Newby, David, Jr.

    Soft x-ray spectroscopy can provide a wealth of information on the electronic structure of solids. In this work, a suite of soft x-ray spectroscopies is applied to organic and inorganic materials with potential applications in electronic and energy generation devices. Using the techniques of x-ray absorption (XAS), x-ray emission spectroscopy (XES), and x-ray photoemission spectroscopy (XPS), the fundamental properties of these different materials are explored. Cycloparaphenylenes (CPPs) are a recently synthesized family of cyclic hydrocarbons with very interesting properties and many potential applications. Unusual UV/Visible fluorescence trends have spurred a number of theoretical investigations into the electronic properties of the CPP family, but thus far no comprehensive electronic structure measurements have been conducted. XPS, XAS, and XES data for two varieties, [8]- and [10]-CPP, are presented here, and compared with the results of relevant DFT calculations. Turning towards more application-centered investigations, similar measurements are applied to two materials commonly used in solid oxide fuel cell (SOFC) cathodes: La1-xSrxMnO 3 (LSMO) and La1-xSr1- xCo1-yFe yO3 (LSCF). Both materials are structurally perovskites, but they exhibit strikingly different electronic properties. SOFC systems very efficiently produce electricity by catalyzing reactions between oxygen and petroleum-based hydrocarbons at high temperatures (> 800 C). Such systems are already utilized to great effect in many industries, but more widespread adoption could be had if the cells could operate at lower temperatures. Understanding the electronic structure and operational evolution of the cathode materials is essential for the development of better low-temperature fuel cells. LSCF is a mixed ion-electron conductor which holds promise for low-temperature SOFC applications. XPS spectra of LSCF thin films are collected as the films are heated and gas-dosed in a controlled environment. The surface evolution of these films is discussed, and the effects of different gas environments on oxygen vacancy concentration are elucidated. LSMO is commonly used in commercial fuel cell devices. Here the resonant soft x-ray emission (RIXS) spectrum of LSMO is examined, and it is shown that the inelastic x-ray emission structure of LSMO arises from local atomic multiplet effects.

  8. Renaissance in diatomic spectroscopy

    NASA Astrophysics Data System (ADS)

    Tiemann, Eberhard; Knöckel, Horst

    2013-07-01

    New technological developments resulted in several periods of renaissances of spectroscopy, the period on microwaves and later the period with lasers, and led to developments of new models for description of observations, thus to understanding the underlying physics. Today, the exciting period of cold molecules has started and demands for new data from molecular spectroscopy and completion in their modeling. This contribution will describe the status of understanding before the era of "cold molecules" and note open questions when entering the field of cold molecules. Because large varieties of cold molecules are studied, like deeply bound (about 1eV) or very weakly bound (less than 10-7 eV) ones, the spectroscopic tools and the theoretical descriptions have to be largely extended. We will describe recent success regarding different molecules of diatomic alkaliand alkaline-earth atoms as examples and will show how to use the often huge body of spectroscopic data for obtaining predictions for optimal paths to produce ultra cold molecules in a desired molecular state. It is very exciting to combine the results of spectroscopy and of studies of ultra cold ensembles which are influenced by their atom-to-molecule changeover. This allows already to complete the understanding of the electronic structure of atom pairs from infinite internuclear separation down to the range of strongly overlapping electronic distribution in some cases (e.g. KRb or KCs). However, enhanced effort is required for describing quantitatively the discoveries, already published or expected, like a contribution to the field hunting for signatures of time dependence of fundamental constants. For molecules with their rotational and vibrational motion the ratio of electron mass-to-nuclear mass as a fundamental constant shows up as an obvious attraction for spectroscopic studies.

  9. Raman spectroscopy

    SciTech Connect

    Gerrard, D.L.; Bowley, H.J.

    1988-06-15

    The period of this review is from late 1985 to late 1987. During this time over 6000 papers have been published in the scientific literature dealing with many applications of Raman spectroscopy and extending its use to new areas of study. This article covers only those papers that are relevant to the analytical chemist and this necessitates a highly selective approach. There are some areas that have been the subject of many papers with relatively few being of analytical interest. In such cases the reader is referred to appropriate reviews which are detailed in this section.

  10. [Real time quantitative PCR].

    PubMed

    Kim, D W

    2001-04-21

    So far, quantitative techniques, such as PCR and FISH, have been used to detect of DNA and RNA. However, it is difficult to measure and compare the exact amount of amplified products with the results of endpoint analysis in conventional PCR techniques. Theoretically, there is a quantitative relationship between amount of starting target sequence and amount of PCR product at any given cycle. The development of real-time quantitative PCR (RQ-PCR) has eliminated the variability associated with conventional quantitative PCR, thus allowing the routine and reliable quantitation of PCR products. Detection of fluorescence during the thermal cycling process can be performed using iCycler(Bio-Rad), the GeneAmp 5700 or 7700(ABI-PRISM), and Light-Cycler(Roche). Two fluorogenic probes are available for use on real time quantitation. The fluorogenic 5'-nuclease assay(Taqman method) uses a fluorogenic probe to enable the detection of a sequence specific PCR product. Fluorogenic probe is incorporated with the reporter dye on the 5' end and the quencher on the 3' end. The second method uses SYBR Green I dye which is a highly specific double-stranded DNA binding dye. Real-time PCR is able to be possible exact quantitation of DNA and RNA much more precise and reproducible because it is based on CT values acquired during the exponential phase of PCR rather than endpoint. In this review, the detail protocol of real time quantitative PCR technique will be introduced and our recently developed system for exact quantitation of BCR-ABL fusion gene in CML is going to be described. PMID:11708318

  11. Quantitative determination of mebeverine HCl by NMR chemical shift migration

    Microsoft Academic Search

    Ian S. Blagbrough; Manal S. Elmasry; Timothy J. Woodman; Hanaa M. Saleh; Afaf Aboul Kheir

    2009-01-01

    Quantitative 1H NMR spectroscopic methods are not frequently reported, but current NMR instrumentation allows ready access to such data. Mebeverine HCl is an attractive molecule for NMR spectroscopy teaching purposes as it possesses a variety of simple but significant functional groups; we fully assign its 1H and 13C NMR spectra. Using mebeverine HCl, we show that concentration changes, in water

  12. Automated Quantitative Software Verification

    E-print Network

    Oxford, University of

    quantitative properties such as "the worst-case probability that the airbag fails to deploy within 10ms", instead of qualitative properties such as "the airbag eventually deploys". Although many model checking

  13. On Quantitative Rorschach Scales.

    ERIC Educational Resources Information Center

    Haggard, Ernest A.

    1978-01-01

    Two types of quantitative Rorschach scales are discussed: first, those based on the response categories of content, location, and the determinants, and second, global scales based on the subject's responses to all ten stimulus cards. (Author/JKS)

  14. Quantitative PCR Protocol

    NSDL National Science Digital Library

    The Jackson Laboratory (The Jackson Laboratory)

    2012-01-06

    This protocol describes how to genotype mice using Quantitative Polymerase Chain Reaction (PCR). The protocol focuses specifically on Ts65Dn mice, but can be used as a basis for genotyping ohter strains.

  15. Qualitative and quantitative analysis of mixtures of compounds containing both hydrogen and deuterium

    NASA Technical Reports Server (NTRS)

    Crespi, H. L.; Harkness, L.; Katz, J. J.; Norman, G.; Saur, W.

    1969-01-01

    Method allows qualitative and quantitative analysis of mixtures of partially deuterated compounds. Nuclear magnetic resonance spectroscopy determines location and amount of deuterium in organic compounds but not fully deuterated compounds. Mass spectroscopy can detect fully deuterated species but not the location.

  16. Quantitative Intramolecular Singlet Fission in Bipentacenes.

    PubMed

    Sanders, Samuel N; Kumarasamy, Elango; Pun, Andrew B; Trinh, M Tuan; Choi, Bonnie; Xia, Jianlong; Taffet, Elliot J; Low, Jonathan Z; Miller, John R; Roy, Xavier; Zhu, X-Y; Steigerwald, Michael L; Sfeir, Matthew Y; Campos, Luis M

    2015-07-22

    Singlet fission (SF) has the potential to significantly enhance the photocurrent in single-junction solar cells and thus raise the power conversion efficiency from the Shockley-Queisser limit of 33% to 44%. Until now, quantitative SF yield at room temperature has been observed only in crystalline solids or aggregates of oligoacenes. Here, we employ transient absorption spectroscopy, ultrafast photoluminescence spectroscopy, and triplet photosensitization to demonstrate intramolecular singlet fission (iSF) with triplet yields approaching 200% per absorbed photon in a series of bipentacenes. Crucially, in dilute solution of these systems, SF does not depend on intermolecular interactions. Instead, SF is an intrinsic property of the molecules, with both the fission rate and resulting triplet lifetime determined by the degree of electronic coupling between covalently linked pentacene molecules. We found that the triplet pair lifetime can be as short as 0.5 ns but can be extended up to 270 ns. PMID:26102432

  17. Quantitative receptor autoradiography

    SciTech Connect

    Boast, C.A.; Snowhill, E.W.; Altar, C.A.

    1986-01-01

    Quantitative receptor autoradiography addresses the topic of technical and scientific advances in the sphere of quantitative autoradiography. The volume opens with a overview of the field from a historical and critical perspective. Following is a detailed discussion of in vitro data obtained from a variety of neurotransmitter systems. The next section explores applications of autoradiography, and the final two chapters consider experimental models. Methodological considerations are emphasized, including the use of computers for image analysis.

  18. Online Resource for Spectroscopy

    NSDL National Science Digital Library

    SpectroscopyNOW.com bills itself as an online resource serving the spectroscopy community. There are tutorials and featured articles for 8 types of spectroscopy as well as information on chemometrics and proteomics.

  19. Quantitative spectroscopy of micron-thick liquid films

    Microsoft Academic Search

    C. K. N. Patel; A. C. Tam

    1980-01-01

    We demonstrate a new sensitive spectroscopic technique for highly transparent micron-thick liquid films sandwiched between transparent substrates. A pulsed dye laser irradiates the film, producing (via the optoacoustic effect) a transient ultrasonic wave which is launched into the substrate and detected by a piezoelectric transducer bonded to the substrate. This technique is illustrated by measuring the absorption lines of films

  20. Quantitative spectroscopy of micron-thick liquid films

    SciTech Connect

    Patel, C.K.N.; Tam, A.C.

    1980-01-01

    We demonstrate a new sensitive spectroscopic technique for highly transparent micron-thick liquid films sandwiched between transparent substrates. A pulsed dye laser irradiates the film, producing (via the optoacoustic effect) a transient ultrasonic wave which is launched into the substrate and detected by a piezoelectric transducer bonded to the substrate. This technique is illustrated by measuring the absorption lines of films of aqueous solutions of rare-earth ion, and absorptions approx.10/sup -5/ can be detected presently. This technique should open up new opportunities to study the spectra of chemi- or physi-adsorbed species on surfaces.

  1. Journal of Quantitative Spectroscopy & Radiative Transfer 99 (2006) 341348

    E-print Network

    2006-01-01

    ). 1 Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin CompanyV blackbody-like radiators [3] are presently used for inertial confinement fusion studies and other work

  2. Journal of Quantitative Spectroscopy & Radiative Transfer 73 (2002) 285296

    E-print Network

    Fan, Tai-Hsi

    2002-01-01

    materials processing applications ranging from metallurgical slag foaming to batch foams in glass melting and predictive models for the apparent radiative properties of a hemispherical shell exposed to incident for the purpose of validation of an analytical model. The study provides fundamental information on radiative

  3. Journal of Quantitative Spectroscopy & Radiative Transfer 72 (2002) 531550

    E-print Network

    Siewert, Charles E.

    2002-01-01

    -ordinates method is then used to solve the pseudo-problem, and so, after both MATLAB and FORTRAN versions to develop precise and accurate numerical schemes for the computation of thermo- uid parameters for particle

  4. Journal of Quantitative Spectroscopy & Radiative Transfer 102 (2006) 2536

    E-print Network

    2006-01-01

    microscopy measurements. An automated procedure was developed to construct a realistic three of flow cytometry as a powerful technique of cell analysis and diagnosis in cell biology and clinics requires continuous improvement in instrumentation, and development of accurate and efficient modeling

  5. Reflectance spectroscopy: quantitative analysis techniques for remote sensing applications.

    USGS Publications Warehouse

    Clark, R.N.; Roush, T.L.

    1984-01-01

    Several methods for the analysis of remotely sensed reflectance data are compared, including empirical methods and scattering theories, both of which are important for solving remote sensing problems. The concept of the photon mean path length and the implications for use in modeling reflectance spectra are presented.-from Authors

  6. Reflectance Spectroscopy: Quantitative Analysis Techniques for Remote Sensing Applications

    Microsoft Academic Search

    Roger N. Clark; Ted L. Roush

    1984-01-01

    Several methods for the analysis of remotely sensed reflectance data are compared, including empirical methods and scattering theories, both of which are important for solving remote sensing problems. The concept of the photon mean optical path length and the implications for use in modeling reflectance spectra are presented. It is shown that the mean optical path length in a particulate

  7. Journal of Quantitative Spectroscopy & Radiative Transfer 7980 (2003) 11391157

    E-print Network

    2003-01-01

    . Introduction Analyses based on the data from the Shuttle-based Lidar In-space Technology Experiment (LITE Code 916, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA Received 20 May 2002; accepted 1, an imaging infrared radiometer, and a wide ÿeld camera, will provide an unprecedented data set for the study

  8. Quantitative NMR spectroscopy of biologically active substances and excipients

    Microsoft Academic Search

    Tanja Beyer; Bernd Diehl; Ulrike Holzgrabe

    2010-01-01

    Biologically active ingredients and excipients are the essentials of a drug formulation, such as a tablet, dragee, solution,\\u000a etc. Quality control of such substances thus plays a pivotal role in the production process of pharmaceutical drugs. Since\\u000a these agents often exhibit complex structures, consist of multiple components, or lack of a chromophore, traditional means\\u000a of characterization are often not feasible.

  9. Quantitative Rapid Scan EPR Spectroscopy at 258 MHz

    PubMed Central

    Quine, Richard W.; Rinard, George A.; Eaton, Sandra S.; Eaton, Gareth R.

    2011-01-01

    Experimental data obtained with an electron paramagnetic resonance (EPR) rapid scan spectrometer were translated through the reverse transfer functions of the spectrometer hardware to the sample position. Separately, theoretical calculations were performed to predict signal and noise amplitudes at the sample position for specified experimental conditions. A comparison was then made between the translated experimental values and the calculated values. Excellent agreement was obtained. PMID:20382055

  10. Journal of Quantitative Spectroscopy & Radiative Transfer 101 (2006) 381382

    E-print Network

    2006-01-01

    been a major stumbling block for performing efficient computer calculations of multiple scattering paper on polarized light transfer published in 1969 [1]. After that Joop started collaborating with Dr

  11. Journal of Quantitative Spectroscopy & Radiative Transfer 81 (2003) 385394

    E-print Network

    Limpouch, Jiri

    2003-01-01

    .elsevier.com/locate/jqsrt Spectroscopic characterization of plasma densities of laser-irradiated Al foils O. Rennera;c;, J. Limpouchb, E analysis of K-shell emission simultaneously observed at the irradiated and unirradiated surface of laser-exploded foils is reported. The space-dependent spectral line widths and relative shifts in the positions

  12. Journal of Quantitative Spectroscopy & Radiative Transfer 103 (2007) 447459

    E-print Network

    Baum, Bryan A.

    2007-01-01

    spectral radiance at the top of the atmosphere (TOA). In FIRTM2 a pre-computed library of cloud reflectance radiative transfer model for overlapping clouds Jianguo Niua , Ping Yanga,Ã, Hung-Lung Huangb , James E&M University, College Station, TX 77843, USA b Cooperative Institute of Satellite Study University of Wisconsin

  13. Journal of Quantitative Spectroscopy & Radiative Transfer 105 (2007) 356

    E-print Network

    2007-01-01

    that the total scattered field at the observation point can be expressed as a superposition of waves traveling. Chapters 2 and 3 introduce the relevant addition theorems in two and three dimensions while Appendices A for Space Studies, New York, USA E-mail address: mmishchenko@giss.nasa.gov ARTICLE IN PRESS www

  14. Journal of Quantitative Spectroscopy & Radiative Transfer 105 (2007) 467475

    E-print Network

    Nassar, Ray

    2007-01-01

    @larc.nasa.gov (L. Chiou), dweisens@aer.com (D.K. Weisenstein), Emmanuel. Mahieu@ulg.ac.be (E. Mahieu), R average 2-D-model predictions of the COClF stratospheric distribution for 2004 are also reported. r 2006 chemistry ARTICLE IN PRESS www.elsevier.com/locate/jqsrt 0022-4073/$ - see front matter r 2006 Elsevier Ltd

  15. Current status of quantitative rotational spectroscopy for atmospheric research

    NASA Technical Reports Server (NTRS)

    Drouin, Brian J.; Wlodarczak, Georges; Colmont, Jean-Marcel; Rohart, Francois

    2004-01-01

    Remote sensing of rotational transitions in the Earth's atmosphere has become an important method for the retrieval of geophysical temperatures, pressures and chemical composition profiles that requires accurate spectral information. This paper highlights the current status of rotational data that are useful for atmospheric measurements, with a discussion of the types the rotational lineshape measurements that are not generally available in either online repository.

  16. Journal of Quantitative Spectroscopy & Radiative Transfer 96 (2005) 139204

    E-print Network

    Chance, Kelly

    2005-01-01

    -Champagne-Ardenne, Groupe de Spectrome´trie Mole´culaire et Atmosphe´rique, 51062 Reims, France c The College of William, Laboratoire de Physique Mole´culaire et Applications, 75252 Paris, France j Univ. of Mass Lowell, Department software. The line-by-line portion of the database contains spectroscopic parameters for 39 molecules

  17. Journal of Quantitative Spectroscopy & Radiative Transfer 7580 (2003) 953972

    E-print Network

    2003-01-01

    thickness and Angstrom exponent of tropospheric aerosols show no signiÿcant trends over the entire period series of the aerosol optical thickness and Angstrom exponent derived for four separate geographic.elsevier.com/locate/jqsrt Aerosol retrievals from AVHRR radiances: e ects of particle nonsphericity and absorption and an updated

  18. Journal of Quantitative Spectroscopy & Radiative Transfer 7980 (2003) 953972

    E-print Network

    2003-01-01

    thickness and Angstrom exponent of tropospheric aerosols show no signiÿcant trends over the entire period series of the aerosol optical thickness and Angstrom exponent derived for four separate geographic.elsevier.com/locate/jqsrt Aerosol retrievals from AVHRR radiances: e ects of particle nonsphericity and absorption and an updated

  19. Journal of Quantitative Spectroscopy & Radiative Transfer 71 (2001) 383395

    E-print Network

    Marjoribanks, Robin S.

    2001-01-01

    ; Hydrocode 1. Introduction Thomson scattering [1] is a powerful diagnostic of laser-produced plasmas (LPPs, UK Abstract In order to understand the physical processes that occur in laser-produced plasmas it is necessary to diagnose the time-dependent hydrodynamic conditions. Thomson scattering is, in principle

  20. MHD Spectroscopy

    SciTech Connect

    Heeter, R F; Fasoli, A; Testa, D; Sharapov, S; Berk, H L; Breizman, B; Gondhalekar, A; Mantsinen, M

    2004-03-23

    Experiments are conducted on the JET tokamak to assess the diagnostic potential of MHD active and passive spectroscopy, for the plasma bulk and its suprathermal components, using Alfv{acute e}n Eigenmodes (AEs) excited by external antennas and by energetic particles. The measurements of AE frequencies and mode numbers give information on the bulk plasma. Improved equilibrium reconstruction, in particular in terms of radial profiles of density and safety factor, is possible from the comparison between the antenna driven spectrum and that calculated theoretically. Details of the time evolution of the non-monotonic safety factor profile in advanced scenarios can be reconstructed from the frequency of ICRH-driven energetic particle modes. The plasma effective mass can be inferred from the resonant frequency of externally driven AEs in discharges with similar equilibrium profiles. The stability thresholds and the nonlinear development of the instabilities can give clues on energy and spatial distribution of the fast particle population. The presence of unstable AEs provides lower limits in the energy of ICRH generated fast ion tails. Fast ion pressure gradients and their evolution can be inferred from the stability of AEs at different plasma radial positions. Finally, the details of the AE spectrum in the nonlinear stage can be used to obtain information about the fast particle velocity space diffusion.

  1. Quantitative Plant Phosphoproteomics

    PubMed Central

    Kline, Kelli G.; Barrett-Wilt, Gregory A.; Sussman, Michael R.

    2011-01-01

    Protein phosphorylation is a major post-translational modification in plants crucial for the regulation of diverse cellular functions. In the early stages of this field, efforts focused on the qualitative detection, identification, and cataloging of in vivo protein phosphorylation sites. Recently these studies have advanced into utilizing quantitative mass spectrometric measurements, capable of dynamically monitoring changes in phosphorylation levels in response to genetic and environmental alterations. This review will highlight current untargeted and targeted mass spectral technologies used for quantitative phosphoproteome measurements in plants, and provide a discussion of these phosphorylation changes in relation to important biological events. PMID:21764629

  2. Quantitative Hydrocarbon Surface Analysis

    NASA Technical Reports Server (NTRS)

    Douglas, Vonnie M.

    2000-01-01

    The elimination of ozone depleting substances, such as carbon tetrachloride, has resulted in the use of new analytical techniques for cleanliness verification and contamination sampling. The last remaining application at Rocketdyne which required a replacement technique was the quantitative analysis of hydrocarbons by infrared spectrometry. This application, which previously utilized carbon tetrachloride, was successfully modified using the SOC-400, a compact portable FTIR manufactured by Surface Optics Corporation. This instrument can quantitatively measure and identify hydrocarbons from solvent flush of hardware as well as directly analyze the surface of metallic components without the use of ozone depleting chemicals. Several sampling accessories are utilized to perform analysis for various applications.

  3. Trace detection of light elements by laser-induced breakdown spectroscopy (LIBS): Applications to non-conducting materials

    NASA Astrophysics Data System (ADS)

    Khater, Mohamed A.

    2013-10-01

    The existence as well as concentration of light (low-atomic number) elements is directly related to some of the most important properties of almost all materials. Thus, the development of a direct, fast, and sensitive spectroscopic method for the analytical quantification of these elements is considered an important continuing challenge in many fields. In this report, results obtained from previous as well as most recent studies regarding trace detection of light elements in non-conducting materials by laser-induced breakdown spectroscopy (LIBS) technique are reviewed for the first time. Firstly, we introduce investigations performed in the far- and vacuum-UV as well as UV-visible-NIR spectral domains, and cover many non-conducting materials including gases, aerosols, soil, cement, and selected organic compounds. The report also demonstrates important analytical results for the elements lithium, beryllium, boron, carbon, fluorine, phosphorus, sulfur, and chlorine. In addition, key characterization information relating to a specific element in a given matrix and state is summarized in such a way that relevant resources can easily be traced. Furthermore, in order to facilitate tracking down the evolution of the technique for a particular material category, a chronological order has been devised. In the second part of the review, the latest developments and advances in instrumentation and methodologies of the LIBS technique, particularly in the realm of light elements detection, are discussed. The sensitive detection of light elements in the UV-VIS-NIR is still unsatisfactory, and more work is needed in order to achieve better analytical performance in terms of precision, accuracy and limits of detection. The author anticipates that significant sensitivity improvements should be realized by combining LIBS, employing femtosecond laser pulses, with other diagnostic techniques based on probing the plasma via diode lasers.

  4. Development and Validation of UV-Visible Spectrophotometric Method for Simultaneous Determination of Eperisone and Paracetamol in Solid Dosage Form

    PubMed Central

    Khanage, Shantaram Gajanan; Mohite, Popat Baban; Jadhav, Sandeep

    2013-01-01

    Purpose: Eperisone Hydrochloride (EPE) is a potent new generation antispasmodic drug which is used in the treatment of moderate to severe pain in combination with Paracetamol (PAR). Both drugs are available in tablet dosage form in combination with a dose of 50 mg for EPE and 325 mg PAR respectively. Methods: The method is based upon Q-absorption ratio method for the simultaneous determination of the EPE and PAR. Absorption ratio method is used for the ratio of the absorption at two selected wavelength one of which is the iso-absorptive point and other being the ?max of one of the two components. EPE and PAR shows their iso-absorptive point at 260 nm in methanol, the second wavelength used is 249 nm which is the ?max of PAR in methanol. Results: The linearity was obtained in the concentration range of 5-25 ?g/mL for EPE and 2-10 ?g/mL for PAR. The proposed method was effectively applied to tablet dosage form for estimation of both drugs. The accuracy and reproducibility results are close to 100% with 2% RSD. Results of the analysis were validated statistically and found to be satisfactory. The results of proposed method have been validated as per ICH guidelines. Conclusion: A simple, precise and economical spectrophotometric method has been developed for the estimation of EPE and PAR in pharmaceutical formulation. PMID:24312876

  5. Track core size estimation in CR39 track detector using atomic force microscope and UV–visible spectrophotometer

    Microsoft Academic Search

    T. Yamauchi; D. Mineyama; H. Nakai; K. Oda; N. Yasuda

    2003-01-01

    The radial size of track cores in CR-39 plastics for several types of ions has been determined by two different methods. First, atomic force microscope observations were performed on the irradiated CR-39 subsequent to the slight chemical etchings. The track core radii for C, O, Ne and Xe ions evaluated from the intersections of the extrapolated lines, fitted to each

  6. Colloidal chemically fabricated ZnO : Cu-based photodetector with extended UV-visible detection waveband.

    PubMed

    Hu, Liang; Zhu, Liping; He, Haiping; Guo, Yanming; Pan, Guoyao; Jiang, Jie; Jin, Yizheng; Sun, Luwei; Ye, Zhizhen

    2013-10-21

    Polycrystalline ZnO : Cu-based film photodetectors with extended detection waveband (UV and visible light) were fabricated using facile colloidal chemistry and a post-annealing process. The obtained detectors are highly sensitive to visible light and can realize the response switch between UV and visible light. A native and extrinsic trap cooperatively controlled space charge limited (SCL) transport mechanism is proposed to understand this complex photoconduction behaviour. PMID:24056887

  7. UV/visible/near-infrared reflectance spectroscopic determination of cotton fiber and trash content in lint cotton waste

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lint cleaning at cotton processing facilities is performed in order to remove the non-lint materials with minimal fiber damage. The resultant waste contains some degree of cotton fiber having good equal qualities, and hence is of great concern for operating cost. Traditional methods for measuring no...

  8. Penetration of UV-visible solar radiation in the global oceans: Insights from ocean color remote sensing

    E-print Network

    processing system was applied to MODIS measurements to reveal the penetration of UVA-visible radiation spec- tral diffuse attenuation coefficient between the surface and depth (z, m) [Austin and Petzold

  9. Long-term accuracy of surface spectroradiometry in the UV, Visible, and near IR domains, and Impacts on Derived Products

    NASA Astrophysics Data System (ADS)

    Kiedron, P.; Berndt, J.; Michalsky, J. J.; Min, Q.

    2001-12-01

    The Rotating Shadowband Spectoradiometer (RSS) is a medium-resolution field spectroradiometer developed for continuous long term field deployment. Successive improvements to the instrument have been operating for the ARM Program and elsewhere since 1997, and provide the large majority of spectral observations taken by ARM within its wavelength domain of 360 - 1100 nm. We also operate the US reference UV spectroradiometric network, consisting of 3 sites with high resolution double monochromators measuring from 280 to 400 nm at higher resolution. We describe the long term maintenance of irradiance scales, conguence tests with solar spectra via Langley regression, and the impact of calibration uncertainties on derived products including aerosol and cloud optical depths, common trace-gas retrievals, and mean photon pathlength from O2 A-band.

  10. Stabilization of diketo tautomer of curcumin by premicellar anionic surfactants: UV-Visible, fluorescence, tensiometric and TD-DFT evidences

    NASA Astrophysics Data System (ADS)

    Dutta, Anisha; Boruah, Bornali; Manna, Arun K.; Gohain, Biren; Saikia, Palash M.; Dutta, Robin K.

    2013-03-01

    A newly observed UV band of aqueous curcumin, a biologically important molecule, in presence of anionic surfactants, viz., sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), and sodium dodecylsulfonate (SDSN) in buffered aqueous solutions has been studied experimentally and theoretically. The 425 nm absorption band of curcumin disappears and a new UV-band is observed at 355 nm on addition of the surfactants in the submicellar concentration range which is reversed as the surfactant concentration approaches the critical micelle concentration (CMC). The observed spectral absorption, fluorescence intensity and surface tension behavior, under optimal experimental conditions of submicellar concentration ranges of the surfactants in the pH range of 2.00-7.00, indicate that the new band is due to the ?-diketo tautomer of curcumin stabilized by interactions between curcumin and the anionic surfactants. The stabilization of the diketo tautomer by submicellar anionic surfactants described here as well as by submicellar cationic surfactant, reported recently, is unique as this is the only such behavior observed in presence of submicellar surfactants of both charge types. The experimental results are in good agreement with the theoretical calculations using ab initio density functional theory combined with time dependent density functional theory (TD-DFT) calculations.

  11. Effective mitigation of photodarkening in Yb-doped lasers based on Al-silicate using UV/visible light

    NASA Astrophysics Data System (ADS)

    Piccoli, Riccardo; Robin, Thierry; Méchin, David; Brand, Thomas; Klotzbach, Udo; Taccheo, Stefano

    2014-03-01

    In this work we discuss the impact of visible light radiation on photodarkening generation in 1070-nm Yb-doped fiber lasers. Simultaneous photodarkening and photobleaching effects induced by 976 nm and 405 nm or 550 nm radiations respectively were investigated. We observed a significant photobleaching effect due to 405 nm radiation but not a complete recovery. A strong absorption of the 405 nm radiation by the excited ions (Excited-State Absorption) was also observed and found as a main limiting factor for the bleaching performance together with observation of photodarkening losses induced by ground-state absorption. To proper define the optimum bleaching wavelength we report, for the first time to the best of our knowledge, the Excited-State Absorption cross section in the visible range. The reported experiments allow to individuate the main parameters defining the optimum bleaching wavelength. In a final experiment, using optimized 550-nm wavelength bleaching radiation, we were able to operate a laser at 93% of its pristine power level compensating a power drop of about 45% in absence of bleaching. The method we present is an effective yet simple way to run laser using standard Al-silicate fibers with doping level over 1026 ions/m3 and high inversion.

  12. Quantitative Graphics in Newspapers.

    ERIC Educational Resources Information Center

    Tankard, James W., Jr.

    The use of quantitative graphics in newspapers requires achieving a balance between being accurate and getting the attention of the reader. The statistical representations in newspapers are drawn by graphic designers whose key technique is fusion--the striking combination of two visual images. This technique often results in visual puns,…

  13. Quantitative tritium imaging

    Microsoft Academic Search

    Ian Stuart Youle

    1999-01-01

    Tritium Imaging electrostatically focuses secondary electrons produced at a surface by beta-particles from tritium in the material form an image of the tritiated areas. It has hitherto been essentially a qualitative technique. The research described here examines quantitative aspects of the process. Of particular importance is the effect of depth of tritium on image intensity. For imaging purposes, tritium must

  14. Recent developments in Mossbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Fujita, F. E.

    1999-05-01

    The Mossbauer effect found by a young nuclear physicist forty years ago has become a useful tool of spectroscopy to investigate solid materials. Through the hyperfine structures of the nuclear levels of Mossbauer isotopes, we can analyse various kinds of structures at the atomic and electronic scale both qualitatively and quantitatively. In this article, recent methodological developments in the Mossbauer spectroscopy with some examples of materials research are introduced. They are the use of the synchrotron orbital radiation and the Coulomb excitation instead of using radio-isotope sources, a high temperature measurement capable of seeing the phase transitions and diffusion processes above 1000 K and the high pressure measurement reaching the level of 100 GPa. Another new technique, the simultaneous detection of Mossbauer gamma-rays, internal conversion electrons and X-rays from different depths of one specimen, is also described. These new developments will stimulate the wider and newer applications of Mossbauer spectroscopy in science and technology related to solid materials.

  15. Stark effect spectroscopy of tryptophan.

    PubMed Central

    Pierce, D W; Boxer, S G

    1995-01-01

    The change in permanent dipole moment (magnitude of delta mu) for the transition from the 1La state to the ground state of tryptophan is the key photophysical parameter for the interpretation of tryptophan fluorescence spectra in terms of static and dynamic dielectric properties of the surrounding medium. We report measurement of this parameter by means of electric field effect (Stark) spectroscopy for N-acetyl-L-tryptophanamide (NATA) in two solvents, the single tryptophan containing peptide melittin, and 5-methoxytryptophan. The values ranged from 5.9 to 6.2 +/- 0.4 Debye/f for NATA and melittin, where f represents the local field correction. The 1Lb magnitude of delta mu was much smaller. Application of Stark spectroscopy to these chromophores required decomposition of the near-UV absorption into the 1La and 1Lb bands by measurement of the fluorescence excitation anisotropy spectrum and represents an extension of the method to systems where band overlap would normally preclude quantitative analysis of the Stark spectrum. The results obtained for 5-methoxytryptophan point out limitations of this method of spectral decomposition. The relevance of these results to the interpretation of steady-state and time-resolved spectroscopy of tryptophan is discussed. PMID:7787044

  16. Long open path Fourier transform spectroscopy measurements of greenhouse gases in the near infrared

    NASA Astrophysics Data System (ADS)

    Griffith, David; Pöhler, Denis; Schmidt, Stefan; Hammer, Samuel; Vardag, Sanam; Levin, Ingeborg; Platt, Ulrich

    2015-04-01

    Atmospheric composition measurements are an important tool to quantify local and regional emissions and sinks of greenhouse gases. But how representative are in situ measurements at one point in an inhomogeneous environment? Open path Fourier Transform Spectroscopy (FTS) measurements potentially offer spatial averaging and continuous measurements of several trace gases (including CO2, CH4, CO and N2O) simultaneously in the same airmass. Spatial averaging over kilometre scales is a better fit to the finest scale atmospheric models becoming available, and helps bridge the gap between models and in situ measurements. With what precision, accuracy and reliability can such measurements be made? Building on our pooled experience in ground-level open path Fourier transform spectroscopy and TCCON solar FTS in the infrared (Wollongong) and long path DOAS techniques in the UV-visible (Heidelberg), we set up a new type of open path measurement system across a 1.5 km one-way path in urban Heidelberg, Germany, using FTS in the near infrared. Direct open-atmosphere measurements of trace gases CO2, CH4, CO and N2O as well as O2 were retrieved from several absorption bands between 4000 and 8000 cm-1 (2.5 - 1.25 micron). At one end of the path an in situ FTIR analyser simultaneously collected well calibrated measurements of the same species for comparison with the open path-integrated measurements. The measurements ran continuously from June - November 2014. We introduce the open path FTS measurement system and present an analysis of the results, including assessment of precision, accuracy relative to co-incident in situ measurements, reliability, and avenues for further improvements and extensions. Short term precision of the open path measurement of CO2 was better than 1 ppm for 5 minute averages and thus sufficient for studies in urban and other non-background environments. Measurement bias relative to calibrated in situ measurements was stable across the measurement period. The system operated reliably with data losses mainly due only to weather events such as rain and fog preventing transmission of the IR beam. In principle the system can be improved to provide longer pathlengths and higher precision.

  17. Energy & Climate: Getting Quantitative

    NASA Astrophysics Data System (ADS)

    Wolfson, Richard

    2011-11-01

    A noted environmentalist claims that buying an SUV instead of a regular car is energetically equivalent to leaving your refrigerator door open for seven years. A fossil-fuel apologist argues that solar energy is a pie-in-the-sky dream promulgated by na"ive environmentalists, because there's nowhere near enough solar energy to meet humankind's energy demand. A group advocating shutdown of the Vermont Yankee nuclear plant claims that 70% of its electrical energy is lost in transmission lines. Around the world, thousands agitate for climate action, under the numerical banner ``350.'' Neither the environmentalist, the fossil-fuel apologist, the antinuclear activists, nor most of those marching under the ``350'' banner can back up their assertions with quantitative arguments. Yet questions about energy and its environmental impacts almost always require quantitative answers. Physics can help! This poster gives some cogent examples, based on the newly published 2^nd edition of the author's textbook Energy, Environment, and Climate.

  18. Effect of photobleaching on calibration model development in biological Raman spectroscopy

    E-print Network

    Barman, Ishan

    A major challenge in performing quantitative biological studies using Raman spectroscopy lies in overcoming the influence of the dominant sample fluorescence background. Moreover, the prediction accuracy of a calibration ...

  19. Macropinosome quantitation assay

    PubMed Central

    Wang, Jack T.H.; Teasdale, Rohan D.; Liebl, David

    2014-01-01

    In contrast to phagocytosis, macropinocytosis is not directly initiated by interactions between cell surface receptors and cargo ligands, but is a result of constitutive membrane ruffling driven by dynamic remodelling of cortical actin cytoskeleton in response to stimulation of growth factor receptors. Wang et al. (2010) [13] developed a reliable assay that allows quantitative assessment of the efficiency and kinetics of macropinosome biogenesis and/or maturation in cells where the function of a targeted protein has been perturbed by pharmacological inhibitors or by knock-down or knock-out approaches. In this manuscript we describe a modified quantitative protocol to measure the rate and volume of fluid phase uptake in adherent cells. This assay:•uses fluorescent dextran, microscopy and semi-automated image analysis;•allows quantitation of macropinosomes within large numbers of individual cells;•can be applied also to non-homogenous cell populations including transiently transfected cell monolayers. We present the background necessary to consider when customising this protocol for application to new cell types or experimental variations.

  20. Quantitation of mitral regurgitation.

    PubMed

    Topilsky, Yan; Grigioni, Francesco; Enriquez-Sarano, Maurice

    2011-01-01

    Mitral regurgitation (MR) is the most frequent valve disease. Nevertheless, evaluation of MR severity is difficult because standard color flow imaging is plagued by considerable pitfalls. Modern surgical indications in asymptomatic patients require precise assessment of MR severity. MR severity assessment is always comprehensive, utilizing all views and methods. Determining trivial/mild MR is usually easy, based on small jet and flow convergence. Specific signs of severe MR (pulmonary venous flow systolic reversal or severe mitral lesion) are useful but insensitive. Quantitative methods, quantitative Doppler (measuring stroke volumes) and flow convergence (aka PISA method), measure the lesion severity as effective regurgitant orifice (ERO) and volume overload as regurgitant volume (RVol). Interpretation of these numbers should be performed in context of specific MR type. In organic MR (intrinsic valve lesions) ERO ? 0.40 cm(2) and RVol ? 60 mL are associated with poor outcome, while in functional MR ERO ? 0.20 cm(2) and RVol ? 30 mL mark reduced survival. While MR assessment should always be comprehensive, quantitative assessment of MR provides measures that are strongly predictive of outcome and should be the preferred approach. The ERO and RVol measured by these methods require interpretation in causal context to best predict outcome and determine MR management. PMID:22041039

  1. Computational vaccinology: quantitative approaches.

    PubMed

    Flower, Darren R; McSparron, Helen; Blythe, Martin J; Zygouri, Christianna; Taylor, Debra; Guan, Pingping; Wan, Shouzhan; Coveney, Peter V; Walshe, Valerie; Borrow, Persephone; Doytchinova, Irini A

    2003-01-01

    The immune system is hierarchical and has many levels, exhibiting much emergent behaviour. However, at its heart are molecular recognition events that are indistinguishable from other types of biomacromolecular interaction. These can be addressed well by quantitative experimental and theoretical biophysical techniques, and particularly by methods from drug design. We review here our approach to computational immunovaccinology. In particular, we describe the JenPep database and two new techniques for T cell epitope prediction. One is based on quantitative structure-activity relationships (a 3D-QSAR method based on CoMSIA and another 2D method based on the Free-Wilson approach) and the other on atomistic molecular dynamic simulations using high performance computing. JenPep (http://www.jenner.ar.uk/ JenPep) is a relational database system supporting quantitative data on peptide binding to major histocompatibility complexes, TAP transporters, TCR-pMHC complexes, and an annotated list of B cell and T cell epitopes. Our 2D-QSAR method factors the contribution to peptide binding from individual amino acids as well as 1-2 and 1-3 residue interactions. In the 3D-QSAR approach, the influence of five physicochemical properties (volume, electrostatic potential, hydrophobicity, hydrogen-bond donor and acceptor abilities) on peptide affinity were considered. Both methods are exemplified through their application to the well-studied problem of peptide binding to the human class I MHC molecule HLA-A*0201. PMID:14712934

  2. Analytical 13 C NMR spectroscopy of fatty quaternary amines

    Microsoft Academic Search

    E. H. Fairchild

    1982-01-01

    Natural abundance13C nuclear magnetic resonance spectroscopy (CMR) has been used for the rapid, nondestructive analysis of fatty quaternary ammonium\\u000a compounds. Quantitative analysis of mixtures of mono-, di-and tri-fatty ammonium chlorides can be accommpublished under conditions\\u000a that do not involve heat or extremes of pH and that are independent of solvent present. In order to determine optimal conditions\\u000a for quantitative studies,

  3. The Influence of Protein Environment on the Low Temperature Electronic Spectroscopy of Zn-Substituted Cytochrome c

    E-print Network

    Sharp, Kim

    and yeast cytochrome c, which show the greatest difference in the UV-visible band splittings, Stark effect generated by charged and polar groups9-16 or from axial ligation to the heme iron by one or more amino acid

  4. Recent Trends on the Use of Infrared Spectroscopy to Trace and Authenticate Natural and Agricultural Food Products

    Microsoft Academic Search

    D. Cozzolino

    2012-01-01

    Abstract: Verification of the authenticity of natural and agricultural foods has become a potential application of spectroscopic methods such as ultraviolet (UV), visible (VIS), near infrared (NIR), and mid-infrared (MIR). Adulteration can take many forms, including the addition of sugars, acids, volatile oils, overdilution of concentrate, addition of juices of other fruits, use of concentrate in a fresh product, and

  5. Characterization of chromophoric dissolved organic matter (CDOM) in the Baltic Sea by excitation emission matrix fluorescence spectroscopy

    Microsoft Academic Search

    Piotr Kowalczuk; Joanna Ston; William J. Cooper; Robert F. Whitehead; Michael J. Durako

    Chromophoric dissolved organic matter (CDOM) is the major light absorber in the Baltic Sea. In this study, excitation emission matrix (EEM) fluorescence spectra and UV-visible absorption spectra of CDOM are reported as a function of salinity. Samples from different locations and over different seasons were collected during four cruises in 2002 and 2003 in the Baltic Sea in both Pomeranian

  6. Characterization of chromophoric dissolved organic matter (CDOM) in the Baltic Sea by excitation emission matrix fluorescence spectroscopy

    Microsoft Academic Search

    Piotr Kowalczuk; Joanna Sto?-Egiert; William J. Cooper; Robert F. Whitehead; Michael J. Durako

    2005-01-01

    Chromophoric dissolved organic matter (CDOM) is the major light absorber in the Baltic Sea. In this study, excitation emission matrix (EEM) fluorescence spectra and UV–visible absorption spectra of CDOM are reported as a function of salinity. Samples from different locations and over different seasons were collected during four cruises in 2002 and 2003 in the Baltic Sea in both Pomeranian

  7. Diffuse Reflectance Spectroscopy with a Self-Calibrating Fiber Optic Probe Bing Yu*, Henry Fu, and Nimmi Ramanujam

    E-print Network

    Ramanujam, Nimmi

    University, Durham, NC, 27708 * Tel: 919-660-5033, Email: bing.yu@duke.edu 2. Motivation · UV-Visible DRS and with different instruments and probes. Fitzpatrick Institute for Photonics 3. Experimental Setup · The UV-VIS DRS. Reference Phantom 14 Spectralon Puck Standard Self-Calibration Day 1 Day 2 Combined Day 1 Day 2 Combined

  8. Quantitative molecular methods in virology

    Microsoft Academic Search

    M. Clementi; S. Menzo; A. Manzin; P. Bagnarelli

    1995-01-01

    Summary During the past few years, significant technical effort was made to develop molecular methods for the absolute quantitation of nucleic acids in biological samples. In virology, semi-quantitative and quantitative techniques of different principle, complexity, and reliability were designed, optimized, and applied in basic and clinical researches. The principal data obtained in successful pilot applications in vivo are reported in

  9. Heterodyne laser spectroscopy system

    SciTech Connect

    Wyeth, R.W.; Paisner, J.A.; Story, T.

    1989-03-28

    A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency and the like, and provides spectral analysis of a laser beam.

  10. Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions

    SciTech Connect

    Bradforth, S.E.

    1992-11-01

    The transition state region of a neutral bimolecular reaction may be experimentally investigated by photoelectron spectroscopy of an appropriate negative ion. The photoelectron spectrum provides information on the spectroscopy and dynamics of the short lived transition state and may be used to develop model potential energy surfaces that are semi-quantitative in this important region. The principles of bound [yields] bound negative ion photoelectron spectroscopy are illustrated by way of an example: a full analysis of the photoelectron bands of CN[sup [minus

  11. Quantitative biomedical mass spectrometry

    NASA Astrophysics Data System (ADS)

    de Leenheer, Andrép; Thienpont, Linda M.

    1992-09-01

    The scope of this contribution is an illustration of the capabilities of isotope dilution mass spectrometry (IDMS) for quantification of target substances in the biomedical field. After a brief discussion of the general principles of quantitative MS in biological samples, special attention will be paid to new technological developments or trends in IDMS from selected examples from the literature. The final section will deal with the use of IDMS for accuracy assessment in clinical chemistry. Methodological aspects considered crucial for avoiding sources of error will be discussed.

  12. A Quantitative Occam's Razor

    E-print Network

    Rafael D. Sorkin

    2005-11-29

    This paper derives an objective Bayesian "prior" based on considerations of entropy/information. By this means, it produces a quantitative measure of goodness of fit (the "H-statistic") that balances higher likelihood against the number of fitting parameters employed. The method is intended for phenomenological applications where the underlying theory is uncertain or unknown. For example, it can help decide whether the large angle anomalies in the CMB data should be taken seriously. I am therefore posting it now, even though it was published before the arxiv existed.

  13. Dielectric spectroscopy in time and frequency domain applied to diagnostics of power transformers

    Microsoft Academic Search

    Uno Gafvert; Lars Adeen; Matz Tapper; Parviz Ghasemi; B. Jonsson

    2000-01-01

    Dielectric spectroscopy in the time- and frequency domain has been used to assess the quality of the insulation systems of a number of power transformers at the Ringhals nuclear power station. Three different methods were used: low frequency dielectric spectroscopy measurements (FDS), time domain polarisation\\/depolarisation current measurements (PDC) and return voltage polarisation spectra (RVM). The results were analysed and quantitatively

  14. Measurement of Negative Ion Density in an Oxygen DC Glow Discharge by Optogalvanic Photodetachment Spectroscopy

    Microsoft Academic Search

    Yoshinobu Matsuda; Hitomi Nagamatsu; Hiroshi Fujiyama

    1998-01-01

    We measured the local density of oxygen negative ions (O^-, O_2^-) in an O2 dc glow discharge by laser optogalvanic photedetachment spectroscopy. The advantages of the photedetachment spectroscopy are its simplicity, quantitative capability for density evaluation, and straightforward data analysis compared with other diagnostics. However, the use of a probe for collecting photodetached electrons in reactive plasma environment, a careful

  15. INFRARED SPECTROSCOPY: A TOOL FOR DETERMINATION OF THE DEGREE OF CONVERSION IN DENTAL COMPOSITES

    PubMed Central

    Moraes, Luciene Gonçalves Palmeira; Rocha, Renata Sanches Ferreira; Menegazzo, Lívia Maluf; de AraÚjo, Eudes Borges; Yukimitu, Keizo; Moraes, João Carlos Silos

    2008-01-01

    Infrared spectroscopy is one of the most widely used techniques for measurement of conversion degree in dental composites. However, to obtain good quality spectra and quantitative analysis from spectral data, appropriate expertise and knowledge of the technique are mandatory. This paper presents important details to use infrared spectroscopy for determination of the conversion degree. PMID:19089207

  16. Molecular Force Spectroscopy on Cells

    NASA Astrophysics Data System (ADS)

    Liu, Baoyu; Chen, Wei; Zhu, Cheng

    2015-04-01

    Molecular force spectroscopy has become a powerful tool to study how mechanics regulates biology, especially the mechanical regulation of molecular interactions and its impact on cellular functions. This force-driven methodology has uncovered a wealth of new information of the physical chemistry of molecular bonds for various biological systems. The new concepts, qualitative and quantitative measures describing bond behavior under force, and structural bases underlying these phenomena have substantially advanced our fundamental understanding of the inner workings of biological systems from the nanoscale (molecule) to the microscale (cell), elucidated basic molecular mechanisms of a wide range of important biological processes, and provided opportunities for engineering applications. Here, we review major force spectroscopic assays, conceptual developments of mechanically regulated kinetics of molecular interactions, and their biological relevance. We also present current challenges and highlight future directions.

  17. Surface inspection using FTIR spectroscopy

    NASA Technical Reports Server (NTRS)

    Powell, G. L.; Smyrl, N. R.; Williams, D. M.; Meyers, H. M., III; Barber, T. E.; Marrero-Rivera, M.

    1995-01-01

    The use of reflectance Fourier transform infrared (FTIR) spectroscopy as a tool for surface inspection is described. Laboratory instruments and portable instruments can support remote sensing probes that can map chemical contaminants on surfaces with detection limits under the best of conditions in the sub-nanometer range, i.e.. near absolute cleanliness, excellent performance in the sub-micrometer range, and useful performance for films tens of microns thick. Examples of discovering and quantifying contamination such as mineral oils and greases, vegetable oils, and silicone oils on aluminum foil, galvanized sheet steel, smooth aluminum tubing, and sandblasted 7075 aluminum alloy and D6AC steel. The ability to map in time and space the distribution of oil stains on metals is demonstrated. Techniques associated with quantitatively applying oils to metals, subsequently verifying the application, and non-linear relationships between reflectance and the quantity oil are described.

  18. Quantitative analysis of NMR spectra with chemometrics

    NASA Astrophysics Data System (ADS)

    Winning, H.; Larsen, F. H.; Bro, R.; Engelsen, S. B.

    2008-01-01

    The number of applications of chemometrics to series of NMR spectra is rapidly increasing due to an emerging interest for quantitative NMR spectroscopy e.g. in the pharmaceutical and food industries. This paper gives an analysis of advantages and limitations of applying the two most common chemometric procedures, Principal Component Analysis (PCA) and Multivariate Curve Resolution (MCR), to a designed set of 231 simple alcohol mixture (propanol, butanol and pentanol) 1H 400 MHz spectra. The study clearly demonstrates that the major advantage of chemometrics is the visualisation of larger data structures which adds a new exploratory dimension to NMR research. While robustness and powerful data visualisation and exploration are the main qualities of the PCA method, the study demonstrates that the bilinear MCR method is an even more powerful method for resolving pure component NMR spectra from mixtures when certain conditions are met.

  19. Quantitative Chemical Imaging with Multiplex Stimulated Raman Scattering Microscopy

    PubMed Central

    Fu, Dan; Lu, Fa-Ke; Zhang, Xu; Freudiger, Christian; Pernik, Douglas R.; Holtom, Gary; Xie, Xiaoliang Sunney

    2012-01-01

    Stimulated Raman scattering (SRS) microscopy is a newly developed label-free chemical imaging technique that overcomes the speed limitation of confocal Raman while avoiding the nonresonant-background problem of coherent anti-Stokes Raman scattering (CARS) microscopy. Previous demonstrations were limited to single Raman band measurement. We present a novel modulation multiplexing approach that allows real-time detection of multiple species using the fast Fourier-transform. We demonstrate quantitative determination of chemical concentration of a ternary mixture. Furthermore, two imaging applications are pursued: (1) quantitative determination of oil content, as well as pigment and protein concentration in microalgae cultures; (2) 3D high resolution imaging of blood, lipids, and protein distribution in ex vivo mouse skin tissue. We believe quantitative multiplex SRS uniquely combines the advantage of fast label-free imaging with the fingerprinting capability of Raman spectroscopy and enables numerous applications lipid biology as well as biomedical imaging. PMID:22316340

  20. Quantitative and qualitative characteristics of dissolved organic matter from eight dominant aquatic macrophytes in Lake Dianchi, China.

    PubMed

    Qu, Xiaoxia; Xie, Li; Lin, Ying; Bai, Yingchen; Zhu, Yuanrong; Xie, Fazhi; Giesy, John P; Wu, Fengchang

    2013-10-01

    The aim of this research was to determine and compare the quantitative and qualitative characteristics of dissolved organic matters (DOM) from eight aquatic macrophytes in a eutrophic lake. C, H, N, and P in ground dry leaves and C, N, and P in DOM of the species were determined, and C/N, C/P, C/H, DOC/C, TDN/N, TDP/P, DOC/TDN, and DOC/TDP were calculated. Chemical structures of the DOM were characterized by the use of multiple techniques including UV-visible, FT-IR, and (13)C CP/MAS spectra. The results showed subtle differences in quantity and quality of DOM among species and life-forms. Except oriental pepper which had a C/H of 0.7, C/H of all the other species was 0.6. C/N and C/P of ground leaves was 10.5-17.3 and 79.4-225.3, respectively, which were greater in floating and submerged species than in the others. Parrot feather also had a small C/P (102.8). DOC/C, TDN/N, and TDP/P were 7.6-16.8, 5.5-22.6, and 22.9-45.6 %, respectively. Except C/N in emergent and riparian species, C/N in the other species and C/P in all the species were lower in their DOM than in the ground leaves. DOM of the macrophytes had a SUVA254 value of 0.83-1.80. The FT-IR and (13)C NMR spectra indicated that the DOM mainly contained polysaccharides and/or amino acids/proteins. Percent of carbohydrates in the DOM was 37.3-66.5 % and was highest in parrot feather (66.5 %) and crofton weed (61.5 %). DOM of water hyacinth, water lettuce, and sago pondweed may have the greatest content of proteins. Aromaticity of the DOM was from 6.9 % in water lettuce to 17.8 % in oriental pepper. DOM of the macrophytes was also different in polarity and percent of Ar-OH. Distinguished characteristics in quantity and quality of the macrophyte-derived DOM may induce unique environmental consequences in the lake systems. PMID:23666633

  1. Electrochemistry and spectroscopy of electrolytes and cathode materials in room-temperature ionic liquids

    NASA Astrophysics Data System (ADS)

    Ryan, David Martin

    The demonstration of a stable, reversible, alkali metal anode is an important step in the development of practical secondary batteries using room temperature chloroaluminate molten salts as electrolytes. Such melts are made by mixing 1-ethyl-3-methylimidazolium chloride (EMIC) with aluminum chloride, and can be Lewis buffered by adding LiCl or NaCl. It has been shown previously that protons added to a sodium chloride buffered melt as 1-ethyl-3-methyfimidazolium hydrogen dichloride (EMIHCl2) provide a more negative voltage window and nearly reversible deposition-stripping behavior for sodium. It is reported here that triethanolamine hydrogen chloride is effective in widening the voltage window, allows the plating and stripping of both lithium and sodium, and is stable in buffered EMIC/AlCl3 melts for months. It is suggested that deprotonation of one ethanolic group of triethanolamine HCl is responsible for the effect. The electrochemistry and UV-visible spectroscopy of several vanadium oxides have been examined in room temperature melts. By varying the mole ratio of the two components, Lewis basic, neutral and acidic melts were made. Most oxides have very low solubility: V2O4 and V2O3 are insoluble and V2O5 has a solubility limit less than 5 mM, but the solubilities of the salts NaVO 3, Na3VO4, and NH4VO3, VOCl 3 and VOF3 are significantly higher. The electrochemistry of V2O5, NaVO3, Na3VO4, NH4VO3, VOCl3 and VOF3 is similar in neutral and acidic melts. In the neutral melt each compound shows an irreversible reduction at about 0.45V vs. an Al wire reference electrode. In an acidic melt (mole fraction AlCl3 = 0.55) each of these compounds exhibit additional reduction peaks at more positive potentials. Coulometric and spectroscopic data for the 0.45V reduction suggest that mixed oxidation state polyvanadates may be formed. Controlled potential coulometry demonstrated that the reduction at 0.45V was the reduction of V(V) to V(IV) and the more positive reduction peaks were caused by the reduction of some other species of V(V) present in the acidic melts. New room temperature melts have been prepared by mixing Lewis acidic, VOCl3, with Lewis basic, EMIC. The new melts are dark red homogeneous liquids that are very conductive and easily reduced.

  2. Quantitative Species Measurements In Microgravity Combustion Flames

    NASA Technical Reports Server (NTRS)

    Chen, Shin-Juh; Pilgrim, Jeffrey S.; Silver, Joel A.; Piltch, Nancy D.

    2003-01-01

    The capability of models and theories to accurately predict and describe the behavior of low gravity flames can only be verified by quantitative measurements. Although video imaging, simple temperature measurements, and velocimetry methods have provided useful information in many cases, there is still a need for quantitative species measurements. Over the past decade, we have been developing high sensitivity optical absorption techniques to permit in situ, non-intrusive, absolute concentration measurements for both major and minor flames species using diode lasers. This work has helped to establish wavelength modulation spectroscopy (WMS) as an important method for species detection within the restrictions of microgravity-based measurements. More recently, in collaboration with Prof. Dahm at the University of Michigan, a new methodology combining computed flame libraries with a single experimental measurement has allowed us to determine the concentration profiles for all species in a flame. This method, termed ITAC (Iterative Temperature with Assumed Chemistry) was demonstrated for a simple laminar nonpremixed methane-air flame at both 1-g and at 0-g in a vortex ring flame. In this paper, we report additional normal and microgravity experiments which further confirm the usefulness of this approach. We also present the development of a new type of laser. This is an external cavity diode laser (ECDL) which has the unique capability of high frequency modulation as well as a very wide tuning range. This will permit the detection of multiple species with one laser while using WMS detection.

  3. Nano-organic carbon and soot particle measurements in a laminar ethylene diffusion flame

    Microsoft Academic Search

    A. D’Anna; A. Rolando; C. Allouis; P. Minutolo; A. D’Alessio

    2005-01-01

    The formation of carbonaceous particulates in a co-flow laminar diffusion flame has been studied using UV–visible spectroscopy and laser scattering\\/extinction techniques for measurements of volume fractions and particle sizes. Measurements were performed in a non-smoking ethylene–air flame at atmospheric pressure. UV–visible spectroscopy allowed the identification of two classes of particles: soot particles, which absorb light in the whole spectral range

  4. Formation of polythiophene multilayers on solid surfaces by covalent molecular assembly

    Microsoft Academic Search

    Sundaramurthy Jayaraman; Dharmarajan Rajarathnam; M. P. Srinivasan

    2010-01-01

    In this work, we demonstrate the deposition of multilayers of conducting polythiophene films on different substrates with substrate-film and layer-to-layer links established by covalent bonding. The films were characterized by UV–Visible spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy and ellipsometry. Thickness of the films and UV–Visible absorption intensity increased linearly with increase in the number of layers. The covalently bonded

  5. Pre-PCR DNA quantitation of soil and sediment samples: method development and instrument design

    Microsoft Academic Search

    P. C. Stark; K. I. Mullen; K. Banton; R. Russotti; D. Soran; C. R. Kuske

    2000-01-01

    A simple and straightforward method for the quantitation of dsDNA in soil and sediment matrices has been developed to support rapid, in-the-field PCR analysis of environmental samples. This method uses PicoGreen nucleic acid stain, and a combination of UV\\/Vis and fluorescence spectroscopy, to quantitate dsDNA in the presence of interfering humic materials. The practical utility of this approach is that

  6. Application of EEM fluorescence spectroscopy in understanding of the "LIGA" phenomenon in the Bay of Biscay (France)

    NASA Astrophysics Data System (ADS)

    Parot, Jérémie; Susperregui, Nicolas; Rouaud, Vanessa; Dubois, Laurent; Anglade, Nathalie; Parlanti, Edith

    2014-05-01

    Marine mucilage is present in all oceans over the world, and in particular in the Mediterranean Sea and in the Pacific Ocean. Surface water warming and hydrodynamic processes can favor the coalescence of marine mucilage, large marine aggregates representing an ephemeral and extreme habitat for biota. DOM is a heterogeneous, complex mixture of compounds, including extracellular polymeric substances (EPS), with wide ranging chemical properties and it is well known to interact with pollutants and to affect their transport and their fate in aquatic environment. The LIGA French research program focuses on tracing colloidal dissolved organic matter (DOM) sources and cycling in the Bay of Biscay (South Western French coast). This ephemeral phenomenon (called "LIGA" in the South West of France) has been observed more than 750 times since 2010. It presents a great ecological impact on marine ecosystems and has been shown to be concomitant with the development of pathogen organisms. A one-year intensive survey of fluorescent DOM was undertaken. From April 2013 until May 2014, water samples were monthly collected from the Adour River (main fresh water inputs) and from 2 sites in the Bay of Biscay at 3 depths of the water column (surface water, at the maximum of chlorophyll-a, and deep water). Moreover, intensified samplings took place from the appearance of the phenomenon twice a week during 4 weeks. UV/visible absorbance and excitation emission matrix (EEM) fluorescence spectroscopy combined with PARAFAC and PCA analyses have been used to characterize colloidal DOM in the Bay of Biscay in order to estimate DOM sources as well as spatial and temporal variability of DOM properties. The preliminary results, obtained for about 70 samples of this survey, have already highlighted spatial and temporal variations of DOM optical properties and a peculiar fluorescent component (exc300nm/em338nm) was detected while the LIGA phenomenon arises. The appearance of this specific fluorescence signal seems to be correlated with high freshwater and terrestrial DOM inputs combined with physical forcing (flows, swell) as well as a rise in temperature and sunshine. This work already allowed us to identify different sources of colloidal DOM in the Bay of Biscay and highlighted a specific fingerprint of the LIGA phenomenon. The combination of EEM fluorescence spectroscopy with PARAFAC and PCA analyses appears thus to be a very powerful tool for the long term monitoring of such a phenomenon and would be very useful for a better understanding of the biogeochemical processes in marine environments and of the marine colloidal DOM ecodynamics.

  7. Quantitative sensory testing.

    PubMed

    Siao, Peter; Cros, Didier P

    2003-05-01

    Quantitative sensory testing is a reliable way of assessing large and small sensory nerve fiber function. Sensory deficits may be quantified and the data used in parametric statistical analysis in research studies and drug trials. It is an important addition to the neurophysiologic armamentarium, because conventional sensory nerve conduction tests only the large fibers. QST is a psychophysical test and lacks the objectivity of NCS. The results are subject to changes owing to distraction, boredom, mental fatigue, drowsiness, or confusion. When patients are consciously or unconsciously biased toward an abnormal QST result, no psychophysical testing can reliably distinguish these patients from those with organic disease. QST tests the integrity of the entire sensory neuraxis and is of no localizing value. Dysfunction of the peripheral nerves or central nervous system may give rise to abnormalities in QST. As is true for other neurophysiologic tests, QST results should always be interpreted in light of the patient's clinical presentation. Quantitative sensory testing has been shown to be reasonably reproducible over a period of days or weeks in normal subjects. Because longitudinal QST studies of patients in drug trials are usually performed over a period of several months to a few years, reproducibility studies on the placebo-control group should be included. For individual patients, more studies are needed to determine the maximum allowable difference between two QSTs that can be attributed to experimental error. The reproducibility of thermal thresholds may not be as good as that of vibration threshold. Different commercially available QST instruments have different specifications (thermode size, stimulus characteristics), testing protocols, algorithms, and normal values. Only QST instruments and their corresponding methodologies that have been shown to be reproducible should be used for research and patient care. The data in the literature do not allow conclusions regarding the superiority of any QST instruments. The future of QST is promising; however, many factors can affect QST results. As is true for other neurophysiologic tests, QST is susceptible to many extraneous factors and to misuse when not properly interpreted by the clinician. PMID:12795516

  8. New Hadronic Spectroscopy

    E-print Network

    N. Drenska; R. Faccini; F. Piccinini; A. Polosa; F. Renga; C. Sabelli

    2010-06-14

    In the past few years the field of hadron spectroscopy has seen renewed interest due to the pubblication, initially mostly from B-Factories, of evidences of states that do not match regular spectroscopy, but are rather candidates for bound states with additional quarks or gluons. A huge effort in understanding the nature of this new states and in building a new spectroscopy is ongoing. This report reviews the experimental and theoretical state of the art on heavy quarkonium exotic spectroscopy, with particular attention on the steps towards a global picture.

  9. Quantitive DNA Fiber Mapping

    SciTech Connect

    Lu, Chun-Mei; Wang, Mei; Greulich-Bode, Karin M.; Weier, Jingly F.; Weier, Heinz-Ulli G.

    2008-01-28

    Several hybridization-based methods used to delineate single copy or repeated DNA sequences in larger genomic intervals take advantage of the increased resolution and sensitivity of free chromatin, i.e., chromatin released from interphase cell nuclei. Quantitative DNA fiber mapping (QDFM) differs from the majority of these methods in that it applies FISH to purified, clonal DNA molecules which have been bound with at least one end to a solid substrate. The DNA molecules are then stretched by the action of a receding meniscus at the water-air interface resulting in DNA molecules stretched homogeneously to about 2.3 kb/{micro}m. When non-isotopically, multicolor-labeled probes are hybridized to these stretched DNA fibers, their respective binding sites are visualized in the fluorescence microscope, their relative distance can be measured and converted into kilobase pairs (kb). The QDFM technique has found useful applications ranging from the detection and delineation of deletions or overlap between linked clones to the construction of high-resolution physical maps to studies of stalled DNA replication and transcription.

  10. Quantitative Proteomics Isotope Coding Proteomics

    E-print Network

    Richardson, David

    Quantitative Proteomics Isotope Coding Proteomics ­ In-vitro labeling » ICAT » Acid cleavable ICAT quantitation Increased isotope spacing ­ 9 Daltons rather than 8 Daltons ­ Less interference from oxidation;Stable Isotope Labeling by Amino Acids in Cell Culture, SILAC, as a Simple and Accurate Approach

  11. Quantitative epidemiology: Progress and challenges

    Microsoft Academic Search

    Ian R. Dohoo

    2008-01-01

    This manuscript is derived from a presentation at the 2006 AVEPM – Schwabe Symposium which honoured the 2006 recipient of the Calvin Schwabe Award – Dr. S. Wayne Martin. Throughout his career, Dr. Martin was instrumental in furthering the development of quantitative epidemiology. This manuscript highlights some of the recent advances in quantitative methods used in veterinary epidemiology and identifies

  12. Workshop on quantitative dynamic stratigraphy

    SciTech Connect

    Cross, T.A.

    1988-04-01

    This document discusses the development of quantitative simulation models for the investigation of geologic systems. The selection of variables, model verification, evaluation, and future directions in quantitative dynamic stratigraphy (QDS) models are detailed. Interdisciplinary applications, integration, implementation, and transfer of QDS are also discussed. (FI)

  13. Quantitatively Analyzing Stealthy Communication Channels

    E-print Network

    Ryder, Barbara G.

    Quantitatively Analyzing Stealthy Communication Channels Patrick Butler, Kui Xu, and Danfeng. Understand- ing the capacity of such communication channels is important in detect- ing organized cyber and quantitatively analyze new techniques that can be used to hide malicious DNS activities both at the host

  14. Quantitative analysis of software architectures

    Microsoft Academic Search

    Simonetta Balsamo; Marco Bernardoand; Vincenzo Grassi

    Quantitative analysis of software systems is a critical issue in the development of applications for heterogeneous distributed and mobile systems. It has been recognised that performance analysis should be integrated in the software development life cycle since the early stages. We focus on quantitative analysis of software architectures (SA) and in particular on performance models and languages to represent, evaluate

  15. Helping Students Become Quantitatively Literate

    ERIC Educational Resources Information Center

    Piatek-Jimenez, Katrina; Marcinek, Tibor; Phelps, Christine M.; Dias, Ana

    2012-01-01

    In recent years, the term "quantitative literacy" has become a buzzword in the mathematics community. But what does it mean, and is it something that should be incorporated into the high school mathematics classroom? In this article, the authors will define quantitative literacy (QL), discuss how teaching for QL differs from teaching a traditional…

  16. Proton magnetic resonance spectroscopy in multiple sclerosis

    SciTech Connect

    Wolinsky, J.S.; Narayana, P.A.; Fenstermacher, M.J. (Univ. of Texas Health Science Center, Houston (USA))

    1990-11-01

    Regional in vivo proton magnetic resonance spectroscopy provides quantitative data on selected chemical constituents of brain. We imaged 16 volunteers with clinically definite multiple sclerosis on a 1.5 tesla magnetic resonance scanner to define plaque-containing volumes of interest, and obtained localized water-suppressed proton spectra using a stimulated echo sequence. Twenty-five of 40 plaque-containing regions provided spectra of adequate quality. Of these, 8 spectra from 6 subjects were consistent with the presence of cholesterol or fatty acids; the remainder were similar to those obtained from white matter of normal volunteers. This early experience with regional proton spectroscopy suggests that individual plaques are distinct. These differences likely reflect dynamic stages of the evolution of the demyelinative process not previously accessible to in vivo investigation.

  17. Quantitative Luminescence Imaging System

    SciTech Connect

    Batishko, C.R.; Stahl, K.A.; Fecht, B.A.

    1992-12-31

    The goal of the MEASUREMENT OF CHEMILUMINESCENCE project is to develop and deliver a suite of imaging radiometric instruments for measuring spatial distributions of chemiluminescence. Envisioned deliverables include instruments working at the microscopic, macroscopic, and life-sized scales. Both laboratory and field portable instruments are envisioned. The project also includes development of phantoms as enclosures for the diazoluminomelanin (DALM) chemiluminescent chemistry. A suite of either phantoms in a variety of typical poses, or phantoms that could be adjusted to a variety of poses, is envisioned. These are to include small mammals (rats), mid-sized mammals (monkeys), and human body parts. A complete human phantom that can be posed is a long-term goal of the development. Taken together, the chemistry and instrumentation provide a means for imaging rf dosimetry based on chemiluminescence induced by the heat resulting from rf energy absorption. The first delivered instrument, the Quantitative Luminescence Imaging System (QLIS), resulted in a patent, and an R&D Magazine 1991 R&D 100 award, recognizing it as one of the 100 most significant technological developments of 1991. The current status of the project is that three systems have been delivered, several related studies have been conducted, two preliminary human hand phantoms have been delivered, system upgrades have been implemented, and calibrations have been maintained. Current development includes sensitivity improvements to the microscope-based system; extension of the large-scale (potentially life-sized targets) system to field portable applications; extension of the 2-D large-scale system to 3-D measurement; imminent delivery of a more refined human hand phantom and a rat phantom; rf, thermal and imaging subsystem integration; and continued calibration and upgrade support.

  18. BATSE spectroscopy analysis system

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.; Bansal, Sandhia; Basu, Anju; Brisco, Phil; Cline, Thomas L.; Friend, Elliott; Laubenthal, Nancy; Panduranga, E. S.; Parkar, Nuru; Rust, Brad

    1992-01-01

    The Burst and Transient Source Experiment (BATSE) Spectroscopy Analysis System (BSAS) is the software system which is the primary tool for the analysis of spectral data from BATSE. As such, Guest Investigators and the community as a whole need to know its basic properties and characteristics. Described here are the characteristics of the BATSE spectroscopy detectors and the BSAS.

  19. Frequency modulation (FM) spectroscopy

    Microsoft Academic Search

    G. C. Bjorklund; M. D. Levenson; W. Lenth; C. Ortiz

    1983-01-01

    Frequency modulation (FM) spectroscopy is a new method of optical heterodyne spectroscopy capable of sensitive and rapid measurement of the absorption or dispersion associated with narrow spectral features. The absorption or dispersion is measured by detecting the heterodyne beat signal that occurs when the FM optical spectrum of the probe wave is distorted by the spectral feature of interest. A

  20. Imaging with Raman Spectroscopy

    PubMed Central

    Zhang, Yin; Hong, Hao; Cai, Weibo

    2010-01-01

    Raman spectroscopy, based on the inelastic scattering of a photon, has been widely used as an analytical tool in many research fields. Recently, Raman spectroscopy has also been explored for biomedical applications (e.g. cancer diagnosis) because it can provide detailed information on the chemical composition of cells and tissues. For imaging applications, several variations of Raman spectroscopy have been developed to enhance its sensitivity. This review article will provide a brief summary of Raman spectroscopy-based imaging, which includes the use of coherent anti-Stokes Raman spectroscopy (CARS, primarily used for imaging the C-H bond in lipids), surface-enhanced Raman spectroscopy (SERS, for which a variety of nanoparticles can be used as contrast agents), and single-walled carbon nanotubes (SWNTs, with its intrinsic Raman signal). The superb multiplexing capability of SERS-based Raman imaging can be extremely powerful in future research where different agents can be attached to different Raman tags to enable the interrogation of multiple biological events simultaneously in living subjects. The primary limitations of Raman imaging in humans are those also faced by other optical techniques, in particular limited tissue penetration. Over the last several years, Raman spectroscopy imaging has advanced significantly and many critical proof-of-principle experiments have been successfully carried out. It is expected that imaging with Raman Spectroscopy will continue to be a dynamic research field over the next decade. PMID:20497112

  1. Foundations of Laser Spectroscopy

    Microsoft Academic Search

    Stig Stenholm; John E. Thomas

    1984-01-01

    Presents the theoretical foundations of steady state laser spectroscopy at an elementary level. General foundations and specific features of nonlinear effects are summarized, laser operation and laser spectroscopy are presented, and laser field fluctuations and the effects of field quantization are dealt with. It gives detailed derivations so the reader can work out all results. References are collected in separate

  2. Quantitative approaches for analysing fluxes through plant metabolic networks using NMR and stable isotope labelling

    Microsoft Academic Search

    N. J. Kruger; R. G. Ratcliffe; A. Roscher

    2003-01-01

    The quantitative analysis of metabolic networks is a prerequisite for understanding the integration and regulation of plant metabolism and for devising rational approaches for manipulating resource allocation in plants. The analysis of steady state stable isotope labelling experiments using nuclear magnetic resonance (NMR) spectroscopy has developed into a powerful method for determining these fluxes in micro-organisms and its application to

  3. Quantitative X-ray fluorescence analysis of As-Se glasses and films

    NASA Astrophysics Data System (ADS)

    Bordovski?, G. A.; Marchenko, A. V.; Seregin, P. P.; Smirnova, N. N.; Terukov, E. I.

    2009-11-01

    The concentrations of arsenic and selenium in As100 - x Se x glassy alloys and related films have been determined by the X-ray fluorescence spectroscopy using the external standard technique. It is demonstrated that the proposed approach allows the compositions of As100 - x Se x glasses and films to be quantitatively determined with an accuracy of ? x = ±0.02.

  4. Chemometric analysis of IR external reflection spectra for quantitative determination of BPSG thin films

    SciTech Connect

    Niemczyk, T.M.; Zhang, L.; Franke, J.E. [New Mexico Univ., Albuquerque, NM (United States). Dept. of Chemistry; Haaland, D.M. [Sandia National Labs., Albuquerque, NM (United States); Radigan, K. [National Semiconductor, Santa Clara, CA (United States)

    1993-11-01

    Infrared (IR) reflection spectroscopy has been shown to be useful for making rapid and nondestructive quantitative determinations of B and P contents and film thickness for borophosphosilicate glass (BPSG) thin films on silicon monitor wafers. Preliminary data also show that similarly precise determinations can be made for BPSG films on device wafers.

  5. Quantitative tritium imaging

    NASA Astrophysics Data System (ADS)

    Youle, Ian Stuart

    1999-12-01

    Tritium Imaging electrostatically focuses secondary electrons produced at a surface by beta-particles from tritium in the material form an image of the tritiated areas. It has hitherto been essentially a qualitative technique. The research described here examines quantitative aspects of the process. Of particular importance is the effect of depth of tritium on image intensity. For imaging purposes, tritium must obviously be nearer the surface than the maximum range of a beta particle, (about 2.6mum in graphite, and less in heavier materials). Numerical simulation, however, indicates that sensitivity falls off very rapidly with depth, dropping by 50% within the first 100nm. Simulations also indicate that for all but the shallowest tritium, imaging sensitivity drops exponentially with depth. This is experimentally investigated by implanting specimens with tritium ions of a known energy to give a calculated depth distribution. The surfaces of the specimens are sputtered to change the depth distribution, and the sample is imaged at various stages in the process. The evolution of the image intensity of the sputtered region is compared to the predictions of the numerical model. This technique was partially successful in graphite, but not in aluminum, due to the mobility of tritium in aluminum, and the modification of the aluminum surface by oxidation. Imaging was used to explore the nature of these modifications. In other experiments, tritiated graphite specimens were coated with aluminum, and the image intensity was measured as a function of coating thickness. As the tritium was fixed in atomic traps in the graphite, and the aluminum coatings could be assumed to be unoxidized at the time of deposition, problems previously encountered in aluminum were avoided. In these experiments, image intensity decreased exponentially with coating thickness, as predicted by the mathematical models, although slightly less rapidly than expected. It is also demonstrated that for many typical tritium distributions, the limit of lateral resolution will be that intrinsic to the electrostatic lens system, and will be fairly independent of, (and smaller than), the range of the tritium beta. This implies that imaging using secondary electrons produced by other radioisotopes may be possible with reasonable resolution.

  6. Role of frequency domain optical spectroscopy in the detection of neonatal brain hemorrhage ? A newborn piglet study

    Microsoft Academic Search

    Miljan R. Stankovic; Dev Maulik; Warren Rosenfeld; Phillip G. Stubblefield; Alexander D. Kofinas; Enrico Gratton; Maria Angela Franceschini; Sergio Fantini; Dennis M. Hueber

    2000-01-01

    Objective: Inability of continuous wave (CW) optical spectroscopy to measure changes in scattering, and the use of an arbitrary rather than an actual baseline, makes the CW method highly susceptible to errors that can lead to a false-positive or false-negative diagnosis. Our objective was to assess whether, and to what extent, the use of quantitative frequency domain spectroscopy would improve

  7. Chemical analysis of plasma-polymerized films: The application of X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (NEXAFS) and fourier transform infrared spectroscopy (FTIR)

    Microsoft Academic Search

    I. Retzko; J. F. Friedrich; A. Lippitz; W. E. S. Unger

    2001-01-01

    Selected FTIR, XPS and NEXAFS spectroscopy results obtained with films deposited with different plasma polymerization processes and different monomers (styrene, acetylene, ethylene and butadiene) are presented. In detail FTIR spectra, XPS surveys, XPS valence bands and core level signals including shake-up features as well as carbon K-edge absorption spectra are qualitatively and, in some cases, semi-quantitatively considered. Information on the

  8. Quantitative single-molecule imaging by confocal laser scanning microscopy.

    PubMed

    Vukojevic, Vladana; Heidkamp, Marcus; Ming, Yu; Johansson, Björn; Terenius, Lars; Rigler, Rudolf

    2008-11-25

    A new approach to quantitative single-molecule imaging by confocal laser scanning microscopy (CLSM) is presented. It relies on fluorescence intensity distribution to analyze the molecular occurrence statistics captured by digital imaging and enables direct determination of the number of fluorescent molecules and their diffusion rates without resorting to temporal or spatial autocorrelation analyses. Digital images of fluorescent molecules were recorded by using fast scanning and avalanche photodiode detectors. In this way the signal-to-background ratio was significantly improved, enabling direct quantitative imaging by CLSM. The potential of the proposed approach is demonstrated by using standard solutions of fluorescent dyes, fluorescently labeled DNA molecules, quantum dots, and the Enhanced Green Fluorescent Protein in solution and in live cells. The method was verified by using fluorescence correlation spectroscopy. The relevance for biological applications, in particular, for live cell imaging, is discussed. PMID:19011092

  9. Quantitative Determination of Tip Parameters in Piezoresponse Force Microscopy

    SciTech Connect

    Jesse, Stephen [ORNL; Kalinin, Sergei V [ORNL; Rodriguez, Brian J [ORNL; Eliseev, E. A. [National Academy of Science of Ukraine, Kiev, Ukraine; Morozovska, A. N. [National Academy of Science of Ukraine, Kiev, Ukraine

    2007-01-01

    One of the key limiting factors in the quantitative interpretation of piezoresponse force microscopy (PFM) is the lack of knowledge on the effective tip geometry. Here the authors derive analytical expressions for a 180{sup o} domain wall profile in PFM for the point charge, sphere plane, and disk electrode models of the tip. An approach for the determination of the effective tip parameters from the wall profile is suggested and illustrated for several ferroelectric materials. The calculated tip parameters can be used self-consistently for the interpretation of PFM resolution and spectroscopy data, i.e., linear imaging processes.

  10. Quantitative Determination on Tip Parameters in Piezoresponse Force Microscopy

    SciTech Connect

    Kalinin, Sergei V [ORNL; Jesse, Stephen [ORNL; Rodriguez, Brian J [ORNL; Eliseev, E. A. [National Academy of Science of Ukraine, Kiev, Ukraine; Gopalana, V. [Pennsylvania State University; Morozovska, A. N. [National Academy of Science of Ukraine, Kiev, Ukraine

    2007-01-01

    One of the key limiting factors in the quantitative interpretation of piezoresponse force microscopy (PFM) is the lack of knowledge on the effective tip geometry. Here the authors derive analytical expressions for a 180 degree domain wall profile in PFM for the point charge, sphere plane, and disk electrode models of the tip. An approach for the determination of the effective tip parameters from the wall profile is suggested and illustrated for several ferroelectric materials. The calculated tip parameters can be used self-consistently for the interpretation of PFM resolution and spectroscopy data, i.e., linear imaging processes.

  11. Atomic scale identification of the terminating structure of compound materials by CAICISS (coaxial impact collision ion scattering spectroscopy)

    Microsoft Academic Search

    O. Ishiyama; T. Nishihara; S. Hayashi; M. Shinohara; M. Yoshimoto; T. Ohnishi; H. Koinuma; S. Nishino; J. Saraie

    1997-01-01

    Quantitative surface analysis includes the determination of the elemental composition and the structure of the sample under investigation. Although LEED, XPS, and SPM etc. have been used to investigate the surface structure of the materials, ambiguity remains in determining quantitatively the topmost atomic species and its alignment on an atomic scale. Therefore, we adopted coaxial impact collision ion scattering spectroscopy

  12. Ultrasensitive Laser Spectroscopy.

    ERIC Educational Resources Information Center

    Kliger, David S.

    1985-01-01

    Examines techniques used to make ultrasensitive spectroscopic measurements. They include excitation, thermal lens, photo acoustic, and ionization spectroscopies. Guidelines and methods are provided for each technique; common uses and applications are explained. (DH)

  13. Fluorescence Correlation Spectroscopy

    NSDL National Science Digital Library

    Haustein, Elke

    This paper, which was previously published as part of an online biophysics textbook, provides detailed information about concepts related to fluorescence correlation spectroscopy. Sections of the document include writing on experimental realization, theoretical concepts, and applications of this technology.

  14. Science Experimenter: Reflectance Spectroscopy.

    ERIC Educational Resources Information Center

    Mims, Forrest M., III

    1991-01-01

    Provides construction details for a simple reflectometer that can be utilized for the observational technique known as reflectance spectroscopy. Includes background discussion, applications, calibrating techniques, and typical results. (JJK)

  15. Laser-induced breakdown spectroscopy combined with spatial heterodyne spectroscopy.

    PubMed

    Gornushkin, Igor B; Smith, Ben W; Panne, Ulrich; Omenetto, Nicoló

    2014-01-01

    A spatial heterodyne spectrometer (SHS) is tested for the first time in combination with laser-induced breakdown spectroscopy (LIBS). The spectrometer is a modified version of the Michelson interferometer in which mirrors are replaced by diffraction gratings. The SHS contains no moving parts and the gratings are fixed at equal distances from the beam splitter. The main advantage is high throughput, about 200 times higher than that of dispersive spectrometers used in LIBS. This makes LIBS-SHS a promising technique for low-light standoff applications. The output signal of the SHS is an interferogram that is Fourier-transformed to retrieve the original plasma spectrum. In this proof-of-principle study, we investigate the potential of LIBS-SHS for material classification and quantitative analysis. Brass standards with broadly varying concentrations of Cu and Zn were tested. Classification via principal component analysis (PCA) shows distinct groupings of materials according to their origin. The quantification via partial least squares regression (PLS) shows good precision (relative standard deviation < 10%) and accuracy (within ± 5% of nominal concentrations). It is possible that LIBS-SHS can be developed into a portable, inexpensive, rugged instrument for field applications. PMID:25226262

  16. Electron Energy Loss Spectroscopy of Nitride Semiconductors

    NASA Astrophysics Data System (ADS)

    Yuan, Jun; Gao, Sangpeng; Sun, Yukui

    2004-03-01

    Semiconducting nitride of AlN, GaN, InN and their alloying compounds have becoming important research topic because of their wide band gap and tunability allows light illumination over a wide range of visible wavelength. However, the optoelectronic properties of these materials depend on the composition, strain as well as elemental segregation in a complex manner that still defies conventional analysis. The research in this area would benefit from more careful and detailed characterization. Electron energy loss spectroscopy (EELS), coupled with a focused electron probe, can provide nanoscale information about the electronic structure of the materials. However, the quantitative analysis is complicated by often anisotropic electronic structure. We have developed ab inito electronic structural calculation in connection with magic angle and dichotic spectral analysis to quantitatively study the effect of alloying, lattice strain and phase structure on the fine structure of electron energy loss spectroscopy. Our result can be used to understand the nanoscale atomic and chemical structure of real nitride materials with a view to build up a better microscopic picture governing their interesting optoelectronic properties.

  17. Electronic Spectroscopy & Dynamics

    SciTech Connect

    Mark Maroncelli, Nancy Ryan Gray

    2010-06-08

    The Gordon Research Conference (GRC) on Electronic Spectroscopy and Dynamics was held at Colby College, Waterville, NH from 07/19/2009 thru 07/24/2009. The Conference was well-attended with participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. The GRC on Electronic Spectroscopy & Dynamics showcases some of the most recent experimental and theoretical developments in electronic spectroscopy that probes the structure and dynamics of isolated molecules, molecules embedded in clusters and condensed phases, and bulk materials. Electronic spectroscopy is an important tool in many fields of research, and this GRC brings together experts having diverse backgrounds in physics, chemistry, biophysics, and materials science, making the meeting an excellent opportunity for the interdisciplinary exchange of ideas and techniques. Topics covered in this GRC include high-resolution spectroscopy, biological molecules in the gas phase, electronic structure theory for excited states, multi-chromophore and single-molecule spectroscopies, and excited state dynamics in chemical and biological systems.

  18. Understanding How the Distal Environment Directs Reactivity in Chlorite Dismutase: Spectroscopy and Reactivity of Arg183 Mutants

    PubMed Central

    Blanc, Béatrice; Mayfield, Jeffery A.; McDonald, Claudia A.; Lukat-Rodgers, Gudrun S.; Rodgers, Kenton R.; DuBois, Jennifer L.

    2012-01-01

    The chlorite dismutase from Dechloromonas aromatica (DaCld) catalyzes the highly efficient decomposition of chlorite to O2 and chloride. Spectroscopic, equilibrium thermodynamic, and kinetic measurements have indicated that Cld has two pH sensitive moieties; one is the heme, and Arg183 in the distal heme pocket has been hypothesized to be the second. This active site residue has been examined by site-directed mutagenesis to understand the roles of positive charge and hydrogen bonding in O–O bond formation. Three Cld mutants, Arg183 to Lys (R183K), Arg183 to Gln (R183Q), and Arg183 to Ala (R183A), were investigated to determine their respective contributions to the decomposition of chlorite ion, the spin state and coordination states of their ferric and ferrous forms, their cyanide and imidazole binding affinities, and their reduction potentials. UV–visible and resonance Raman spectroscopies showed that DaCld(R183A) contains five-coordinate high-spin (5cHS) heme, the DaCld(R183Q) heme is a mixture of five-coordinate and six-coordinate high spin (5c/6cHS) heme, and DaCld(R183K) contains six-coordinate low-spin (6cLS) heme. In contrast to wild-type (WT) Cld, which exhibits pKa values of 6.5 and 8.7, all three ferric mutants exhibited pH-independent spectroscopic signatures and kinetic behaviors. Steady state kinetic parameters of the chlorite decomposition reaction catalyzed by the mutants suggest that in WT DaCld the pKa of 6.5 corresponds to a change in the availability of positive charge from the guanidinium group of Arg183 to the heme site. This could be due to either direct acid–base chemistry at the Arg183 side chain or a flexible Arg183 side chain that can access various orientations. Current evidence is most consistent with a conformational adjustment of Arg183. A properly oriented Arg183 is critical for the stabilization of anions in the distal pocket and for efficient catalysis. PMID:22313119

  19. Spectroscopic Studies of Chemical Equilibrium in Supercritical Water: Cr(VI) and NOâ Chemistry

    Microsoft Academic Search

    Kirk J. Ziegler; Jerzy Chlistunoff; Keith P. Johnston

    1999-01-01

    UV-visible spectroscopy is well suited for determining equilibrium constants of acid-base and redox reactions in supercritical water. The recent development of relatively stable organic UV- visible pH indicators for SCW offers the opportunity to characterize buffers and to monitor acid-base titrations. For reactions which contain chromophores such as Cr(VI) and NOx, a series of equilibrium constants have been measured, in

  20. EDITORIAL: Nano Meets Spectroscopy Nano Meets Spectroscopy

    NASA Astrophysics Data System (ADS)

    Birch, David J. S.

    2012-08-01

    The multidisciplinary two-day Nano Meets Spectroscopy (NMS) event was held at the National Physical Laboratory (NPL), Teddington, UK, in September 2011. The event was planned from the outset to be at the interface of several areas—in particular, spectroscopy and nanoscience, and to bring together topics and people with different approaches to achieving common goals in biomolecular science. Hence the meeting cut across traditional boundaries and brought together researchers using diverse techniques, particularly fluorescence and Raman spectroscopy. Despite engaging common problems, these techniques are frequently seen as mutually exclusive with the two communities rarely interacting at conferences. The meeting was widely seen to have lived up to its billing in good measure. It attracted the maximum capacity of ~120 participants, including 22 distinguished speakers (9 from outside the UK), over 50 posters and a vibrant corporate exhibition comprising 10 leading instrument companies and IOP Publishing. The organizers were Professor David Birch (Chair), Dr Karen Faulds and Professor Duncan Graham of the University of Strathclyde, Professor Cait MacPhee of the University of Edinburgh and Dr Alex Knight of NPL. The event was sponsored by the European Science Foundation, the Institute of Physics, the Royal Society of Chemistry, NPL and the Scottish Universities Physics Alliance. The full programme and abstracts are available at http://sensor.phys.strath.ac.uk/nms/program.php. The programme was quite ambitious in terms of the breadth and depth of scope. The interdisciplinary and synergistic concept of 'X meets Y' played well, cross-fertilization between different fields often being a source of inspiration and progress. Fluorescence and Raman spectroscopy provided the core, but the meeting had little repetition and also attracted contributions on more specialist techniques such as CARS, super-resolution, single molecule and chiral methods. In terms of application the event bridged as far as medical application of nanotechnologies. It could have turned out that such a hotchpotch produced an incoherent event that lacked direction and focus, but in truth, as the feedback showed, the delegates revelled in the diversity and depth of quality. Excellent speakers, the common application to biomolecules and common language of spectroscopy were probably the reasons why things worked out so well. I am delighted to bring together in this special feature in Measurement Science and Technology a selection of contributions from the meeting and I thank all the authors for their excellent contributions. Included are papers on nanoparticles, plasmonics, sensing and imaging. This special feature, and indeed similar meetings in the future, will undoubtedly help sustain the 'nanomeeters' message of NMS.

  1. DNA interaction studies and evaluation of biological activity of homo- and hetero-trihalide mononuclear Cu(II) Schiff base complexes. Quantitative structure-activity relationships.

    PubMed

    Chaviara, A T; Kioseoglou, E E; Pantazaki, A A; Tsipis, A C; Karipidis, P A; Kyriakidis, D A; Bolos, C A

    2008-09-01

    A new series of mixed-ligand mono- or hetero-trihalide Cu(II) complexes of the type [Cu(dienXX)Y(YZ(2))], where dienXX=Schiff dibase of diethylenetriamine with 2-thiophene-carboxaldehyde (dienSS), 2-furaldehyde (dienOO) or 2-pyrrole-2-carboxaldehyde (dienNN), Y=Cl, Br and Z=Br, I was synthesized by the reaction of the precursors of the type [Cu(dienXX)Y]Y with iodine or bromine in 1:1 molar ratio. The distorted square pyramidal configuration of the new homo- and hetero-trihalide Cu(II) mononuclear complexes was identified by C, H, N, Cu analysis, spectroscopic methods (IR, UV-visible), molar conductivity and magnetic measurements. The basal plane consists of three nitrogen atoms of the Schiff base and one halogen (terminal) atom while another axially located trihalogen moiety occupies the fifth side of the square pyramid as a YZ(2) entity, adopting an almost linear configuration. The equilibrium geometry of these complexes was further corroborated by theoretical studies at the B3LYP/DGDZVP level. A series of quantum chemical descriptors (e.g. SOMO (singly occupied molecular orbital) LUMO (lowest occupied molecular orbital), SOMO and LUMO energies, SOMO-LUMO gap, dipole moment, polarizability, molar volume, etc.) have been utilized in order to deduce quantitative structure-activity relationships (QSARs). The effect of the new compounds on the single stranded (ss), double stranded (ds) and pDNA led either to the formation of a DNA-complex cationic adduct, or to its degradation, evidenced by DNA electrophoretic mobility and DNA interaction spectroscopic titration studies. Moreover, the antimicrobial activity of Cu(II) complexes against Gram(+) and Gram(-) bacteria can be attributed to the synergistic action of the dissociation species, namely the cationic [Cu(dienXX)Y](+) and anionic [YZ(2)](-) ones. Finally, de Novo linear regression analysis correlating the bioactivity of these complexes with their structural substituents has been carried out, leading to some interesting qualitative observations/conclusions. PMID:18584877

  2. X-ray absorption spectroscopy of bacterial sulfur globules

    Microsoft Academic Search

    Graham N

    2002-01-01

    Sulfur K-edge X-ray absorption spectroscopy is a powerful in situ probe of sulfur biochemistry in intact cells and tissues. Under favorable circumstances the technique can provide quantitative information on the chemical identify of the sulfur species that are present in a sample. Prange et al. have recently reported an X-ray absorption spectroscopic study of bacterial sulfur storage globules. Unfortunately there

  3. The determination of peroxide value by fourier transform infrared spectroscopy

    Microsoft Academic Search

    F. R. van de Voort; A. A. Ismail; J. Sedman; J. Dubois; T. Nicodemo

    1994-01-01

    A rapid method for the quantitative determination of peroxide value (PV) of vegetable oils by Fourier transform infrared (FTIR)\\u000a transmission spectroscopy is described. Calibration standards were prepared by the addition oft-butyl hydroperoxide to a series of vegetable oils, along with random amounts of oleic acid and water. Additional standards\\u000a were derived through the addition of mono- and diglyceride spectral contributions,

  4. Software for quantitative trait analysis

    PubMed Central

    2005-01-01

    This paper provides a brief overview of software currently available for the genetic analysis of quantitative traits in humans. Programs that implement variance components, Markov Chain Monte Carlo (MCMC), Haseman-Elston (H-E) and penetrance model-based linkage analyses are discussed, as are programs for measured genotype association analyses and quantitative trait transmission disequilibrium tests. The software compared includes LINKAGE, FASTLINK, PAP, SOLAR, SEGPATH, ACT, Mx, MERLIN, GENEHUNTER, Loki, Mendel, SAGE, QTDT and FBAT. Where possible, the paper provides URLs for acquiring these programs through the internet, details of the platforms for which the software is available and the types of analyses performed. PMID:16197737

  5. Discrimination of varieties of tea using near infrared spectroscopy by principal component analysis and BP model

    Microsoft Academic Search

    Yong He; Xiaoli Li; Xunfei Deng

    2007-01-01

    Visible\\/near-infrared spectroscopy (NIRS), with the characteristics of high speed, non-destructiveness, high precision and reliable detection data, etc., is a pollution-free, rapid, quantitative and qualitative analysis method. A new approach for discrimination of varieties of tea by means of vis\\/NIR spectroscopy (325–1075nm) was developed in this work. The relationship between the reflectance spectra and tea varieties was established. The spectral data

  6. Characterization of bioscoured cotton fabrics using FT-IR ATR spectroscopy and microscopy techniques

    Microsoft Academic Search

    Qiang Wang; Xuerong Fan; Weidong Gao; Jian Chen

    2006-01-01

    The effects of bioscouring were investigated by characterizing the chemical and physical surface changes of cotton fabrics using a purified pectinase enzyme from Bacillus subtilis strain WSHB04-02. Fourier-transform infrared (FT-IR) attenuated total-reflectance (ATR) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM) techniques were employed. FT-IR ATR spectroscopy provided a fast and semi-quantitative assessment of the removal of pectins

  7. Comparative vibrational spectroscopy for determination of quality parameters in amidated pectins as evaluated by chemometrics

    Microsoft Academic Search

    Søren Balling Engelsen; Lars Nørgaard

    1996-01-01

    The potential of vibrational spectroscopy and chemometrics as a reliable and fast method for the determination of important gel-forming parameters in amidated pectins has been investigated.For a set of 98 amidated pectin samples, six complete spectroscopic ensembles were recorded including NIR, FT-NIR, FT-IR and NIR FT-Raman spectroscopy. For each spectroscopic ensemble, quantitative models based on partial least squares regression (PLS)

  8. Detection of bacteria by time-resolved laser-induced breakdown spectroscopy

    Microsoft Academic Search

    Stéphane Morel; Nicolas Leone; Philippe Adam; Jacques Amouroux

    2003-01-01

    A laser-induced breakdown spectroscopy technique for analyzing biological matter for the detection of biological hazards is investigated. Eight species were considered in our experiment: six bacteria and two pollens in pellet form. The experimental setup is described, then a cumulative intensity ratio is proposed as a quantitative criterion because of its linearity and reproducibility. Time-resolved laser-induced breakdown spectroscopy (TRELIBS) exhibits

  9. Recent developments in low-energy ion scattering spectroscopy (ISS) for surface structural analysis

    Microsoft Academic Search

    M. Aono; M. Katayama; E. Nomura; T. Chassé; D. Choi; M. Kato

    1989-01-01

    Recent years have seen significant progress in low-energy ion scattering spectroscopy (ISS) for surface structural analysis. They include the development of impact-collision ion scattering spectroscopy (ICISS) to make quantitative surface structural analysis possible and the use of alkali ions rather than noble-gas ions in ICISS (ALICISS) to avoid the ambiguity of ion neutralization probability. The latest progress is the development

  10. Characterization and Application of a Grazing Angle Objective for Quantitative Infrared Reflection Microspectroscopy

    NASA Technical Reports Server (NTRS)

    Pepper, Stephen V.

    1995-01-01

    A grazing angle objective on an infrared microspectrometer is studied for quantitative spectroscopy by considering the angular dependence of the incident intensity within the objective's angular aperture. The assumption that there is no angular dependence is tested by comparing the experimental reflectance of Si and KBr surfaces with the reflectance calculated by integrating the Fresnel reflection coefficient over the angular aperture under this assumption. Good agreement was found, indicating that the specular reflectance of surfaces can straight-forwardly be quantitatively integrated over the angular aperture without considering non-uniform incident intensity. This quantitative approach is applied to the thickness determination of dipcoated Krytox on gold. The infrared optical constants of both materials are known, allowing the integration to be carried out. The thickness obtained is in fair agreement with the value determined by ellipsometry in the visible. Therefore, this paper illustrates a method for more quantitative use of a grazing angle objective for infrared reflectance microspectroscopy.

  11. Cham and Charmoniium Spectroscopy

    SciTech Connect

    Petersen, Brian Aa.; /Stanford U., Phys. Dept.

    2006-10-20

    The last few years have seen a revival of interest in charm spectroscopy with more than a dozen new states being reported and hundreds of new theoretical investigations being published. The advent of the B-factories [1,2], with their large, charm-rich data samples, has proven crucial to the discovery and investigation of new charm hadron states, but other experiments have confirmed and complemented the B-factory observations. Much interest has been generated by several new states that do not appear to be easily incorporated in the conventional picture of charm and charmonium mesons. Here, the focus is on the latest experimental results in charm spectroscopy and the determination of the nature of the recently discovered states. Recent experimental results in charm and charmonium spectroscopy are reviewed.

  12. Ultraviolet Spectroscopy of Asteroid (4) Vesta

    E-print Network

    Li, Jian-Yang; Feaga, Lori M; Landsman, Wayne; A'Hearn, Michael F; Mutchler, Max J; Russell, Christopher T; McFadden, Lucy A; Raymond, Carol A

    2011-01-01

    We report a comprehensive review of the UV-visible spectrum and rotational lightcurve of Vesta combining new observations by Hubble Space Telescope and Swift Gamma-ray Burst Observatory with archival International Ultraviolet Explorer observations. The geometric albedos of Vesta from 220 nm to 953 nm are derived by carefully comparing these observations from various instruments at different times and observing geometries. Vesta has a rotationally averaged geometric albedo of 0.09 at 250 nm, 0.14 at 300 nm, 0.26 at 373 nm, 0.38 at 673 nm, and 0.30 at 950 nm. The linear spectral slope as measured between 240 and 320 nm in the ultraviolet displays a sharp minimum near a sub-Earth longitude of 20^{\\circ}, and maximum in the eastern hemisphere. This is consistent with the longitudinal distribution of the spectral slope in the visible wavelength. The photometric uncertainty in the ultraviolet is ~20%, and in the visible wavelengths it is better than 10%. The amplitude of Vesta's rotational lightcurves is ~10% throu...

  13. Enabling Population and Quantitative Genomics

    Microsoft Academic Search

    GREG GIBSON; TRUDY F. C. MACKAY

    2002-01-01

    Summary Dissection of quantitative traits to the nucleotide level requires phenotypic and genotypic analysis of traits on a genome scale. Here we discuss the set of community-wide genetic and molecular resources, including panels of specific types of inbred lines and high density resequencing and SNP detection, that will facilitate such studies. 1. Background

  14. CROP & SOIL SCIENCES Quantitative Genomics

    E-print Network

    Arnold, Jonathan

    CROP & SOIL SCIENCES Quantitative Genomics Committee Membership Dr. Scott Jackson - committee chair Dr. Peng-Wah Chee Department of Crop & Soil Sciences Department of Crop & Soil Sciences University of Horticulture Department of Crop & Soil Sciences University of Georgia University of Georgia 2360 Rainwater Rd

  15. Quantitative genomics of female reproduction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous quantitative trait loci (QTL) for reproductive traits in domestic livestock have been described in the literature. In this chapter, the components needed for detection of reproductive trait QTL are described, including collection of phenotypes, genotypes, and the appropriate statistical ana...

  16. Improvements in quantitative source preparation

    Microsoft Academic Search

    B. Denecke; G. Sibbens; T. Szabo; M. Hult; L. Persson

    2000-01-01

    Quantitative source preparation is indispensable for radionuclide standardisation. To improve the source quality, a device has been developed to accelerate the evaporation of solvents from a drop deposited on a substrate. Short drying times were reached by stirring the rotating drop with multiple jets of dry nitrogen at elevated temperature. Uniform deposits with a large number of small crystals were

  17. Protein Quantitation Using Mass Spectrometry

    PubMed Central

    Zhang, Guoan; Ueberheide, Beatrix M.; Waldemarson, Sofia; Myung, Sunnie; Molloy, Kelly; Eriksson, Jan; Chait, Brian T.; Neubert, Thomas A.; Fenyö, David

    2013-01-01

    Mass spectrometry is a method of choice for quantifying low-abundance proteins and peptides in many biological studies. Here, we describe a range of computational aspects of protein and peptide quantitation, including methods for finding and integrating mass spectrometric peptide peaks, and detecting interference to obtain a robust measure of the amount of proteins present in samples. PMID:20835801

  18. Quantitative phase evaluation of dynamic

    E-print Network

    Chen, Zhongping

    conventional phase-contrast microscopy. © 2008 Society of Photo-Optical Instrumentation Engineers. DOI: 10 advantage of the combination of laser microirradiation and short- coherence interference microscopy. Using.1117/1.2997375 Keywords: laser scissors; short-coherence interference microscopy; quantitative phase imaging; optical

  19. Quantitative Activities for Introductory Astronomy

    Microsoft Academic Search

    Jonathan W. Keohane; J. L. Bartlett; J. P. Foy

    2010-01-01

    We present a collection of short lecture-tutorial (or homework) activities, designed to be both quantitative and accessible to the introductory astronomy student. Each of these involves interpreting some real data, solving a problem using ratios and proportionalities, and making a conclusion based on the calculation. Selected titles include: \\

  20. Tackling quantitatively large dimensionality problems

    Microsoft Academic Search

    F. Campolongo; S. Tarantola; A. Saltelli

    1999-01-01

    A two-step approach to sensitivity analysis of model output in large computational models is proposed. A preliminary screening exercise is suggested in order to identify the subset of the most potentially explanatory factors. Afterwards, a quantitative method is recommended on the subset of preselected inputs. The advantage of the proposed procedure is that, very often, among a large number of