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Sample records for spectroscopy differential scanning

  1. Comparative Study Of Various Grades Of Polyethylene By Differential Scanning Calorimetry (DSC) Correlated With Raman Spectroscopy

    Science.gov (United States)

    Jumeau, Richard; Bourson, Patrice; Ferriol, Michel; Lahure, François; Ducos, Franck; Ligneron, Jérôme

    2011-05-01

    Polyethylene (PE) is a very important material. In 2008, almost 30% of the world plastics production was dedicated to this polymer (70 million tons) [1]. It is a consumer polymer because of its moderate cost of manufacturing and its physical and mechanical properties compatible with various applications in everyday life. Indeed, PE is generally easily processable. It possesses an excellent electric insulation and shock resistance combined with a very good chemical and biological inertia [2]. For each application, there is a particular grade, i.e. a polyethylene with well defined rheological properties. Therefore, it is essential to know how to differentiate these different grades by suitable methods of characterization. Differential Scanning Calorimetry (DSC) is one of the techniques usually used for this purpose. The knowledge of characteristic temperatures such as melting, cold crystallization or glass transition gives information on the viscosity and thus, on the grade of the polymer. DSC also allows the detection of defects, (for example, presence of unmelted pieces). However DSC is a tedious method for on-line quality control, limiting its scope. The determination of the polymer structure represents a major challenge in the industrial world of polymers. Raman spectroscopy, another technique of polymer analysis, is nowadays growing fast because of the advantages it presents. It is a non-destructive method, capable of also giving useful information about the morphology of the polymer. This technique can be perfectly used in industry by means of adapted sensors and devices with more and more reduced dimensions [3]. That technique is used to obtain the characteristic temperatures of PE and information on the polymer structure. The purpose of this article is to establish the correlation between the viscosity of a polymer and its characteristic temperatures obtained by DSC and subsequent possibilities of quality control in industry. These measurements are correlated

  2. Scanning image correlation spectroscopy.

    Science.gov (United States)

    Digman, Michelle A; Gratton, Enrico

    2012-05-01

    Molecular interactions are at the origin of life. How molecules get at different locations in the cell and how they locate their partners is a major and partially unresolved question in biology that is paramount to signaling. Spatio-temporal correlations of fluctuating fluorescently tagged molecules reveal how they move, interact, and bind in the different cellular compartments. Methods based on fluctuations represent a remarkable technical advancement in biological imaging. Here we discuss image analysis methods based on spatial and temporal correlation of fluctuations, raster image correlation spectroscopy, number and brightness, and spatial cross-correlations that give us information about how individual molecules move in cells and interact with partners at the single molecule level. These methods can be implemented with a standard laser scanning microscope and produce a cellular level spatio-temporal map of molecular interactions. Copyright © 2012 WILEY Periodicals, Inc.

  3. Study on the Glass Transition Process of Polymer System Using Differential Scanning Calorimetry and Fourier Transform Infrared Spectroscopy.

    Science.gov (United States)

    Peng, Yong-Jin; Liu, Yu-Ling; Wu, Qiang; Sun, Ping-Chuan

    2017-01-01

    The change in the infrared spectrum of polymer samples with temperature and their differential scanning calorimetry (DSC) experimental results are analyzed. According to the van't Hoff equation at constant pressure, the changes in the absorbance ratio corresponding to high and low vibrational states are calculated, and the apparent enthalpy differences of the vibration energy states transformation of the characteristic group can be obtained. From the experimental results, we can find that characteristic vibration modes of a chemical group in a polymer are under the influence of the glass transition process of the polymer with a different extent. The characteristic vibration modes of the same chemical group behave differently due to the influence of the polymer system at which the chemical moiety is situated.

  4. Identification of nanostructural development in epoxy polymer layered silicate nanocomposites from the interpretation of differential scanning calorimetry and dielectric spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Roman, Frida, E-mail: roman@mmt.upc.edu [Laboratori de Termodinamica, Departament de Maquines i Motors Termics, ETSEIAT, Universitat Politecnica de Catalunya, Carrer Colom 11, 08222 Terrassa (Spain); Calventus, Yolanda, E-mail: calventus@mmt.upc.edu [Laboratori de Termodinamica, Departament de Maquines i Motors Termics, ETSEIAT, Universitat Politecnica de Catalunya, Carrer Colom 11, 08222 Terrassa (Spain); Colomer, Pere, E-mail: colomer@mmt.upc.edu [Laboratori de Termodinamica, Departament de Maquines i Motors Termics, ETSEIAT, Universitat Politecnica de Catalunya, Carrer Colom 11, 08222 Terrassa (Spain); Hutchinson, John M., E-mail: hutchinson@mmt.upc.edu [Laboratori de Termodinamica, Departament de Maquines i Motors Termics, ETSEIAT, Universitat Politecnica de Catalunya, Carrer Colom 11, 08222 Terrassa (Spain)

    2012-08-10

    Highlights: Black-Right-Pointing-Pointer Comparison of DSC and DRS in the cure of epoxy nanocomposites. Black-Right-Pointing-Pointer Dependence of exfoliation of nanocomposite on clay content. Black-Right-Pointing-Pointer Anionically initiated homopolymerisation in PLS nanocomposites. - Abstract: The effect of nanoclay on the non-isothermal cure kinetics of polymer layered silicate nanocomposites based upon epoxy resin is studied by calorimetric techniques (DSC and TGA) and by dielectric relaxation spectroscopy (DRS) in non-isothermal cure at constant heating rate. The cure process takes place by homopolymerisation, initiated anionically using 3 wt% dimethylaminopyridine (DMAP), and the influence of the nanoclay content has been analysed. Interesting differences are observed between the nanocomposites with 2 wt% and 5 wt% clay content. At low heating rates, these samples vitrify and then devitrify during the cure. For the sample with 2 wt% clay, the devitrification is accompanied by a thermally initiated homopolymerisation, which can be identified by DRS but not by DSC. The effect of this is to improve the exfoliation of the nanocomposite with 2 wt% clay, as verified by transmission electron microscopy, with a corresponding increase in the glass transition temperature. These observations are interpreted in respect of the nanocomposite preparation method and the cure kinetics.

  5. Quantifying low amorphous or crystalline amounts of alpha-lactose-monohydrate using X-ray powder diffraction, near-infrared spectroscopy, and differential scanning calorimetry.

    Science.gov (United States)

    Fix, I; Steffens, K J

    2004-05-01

    Efficient and accurate quantification of low amorphous and crystalline contents within pharmaceutical materials still remains a challenging task in the pharmaceutical industry. Since X-ray powder diffraction (XRPD) equipment has improved in recent years, our aim was 1) to investigate the possibility of substantially lowering the detection limits of amorphous or crystalline material to about 1% or 0.5% w/w respectively by applying conventional Bragg Brentano optics, combined with a fast and simple evaluation technique; 2) to perform these measurements within a short time to make it suitable for routine analysis; and 3) to subject the same data sets to a partial least squares regression (PLSR) in order to investigate whether it is possible to improve accuracy and precision compared to the standard integration method. Near-infrared spectroscopy (NIRS) and differential scanning calorimetry (DSC) were chosen as reference method. As model substance, alpha lactose monohydrate was chosen to create calibration curves based on predetermined mixtures of highly crystalline and amorphous substance. In contrast to DSC, XRPD and NIRS revealed an excellent linearity, precision, and accuracy with the percent of crystalline amount and a detectability down to about 0.5% w/w. Chemometric evaluation (partial least squares regression) applied to the XRPD data further improved the quality of our calibration.

  6. Vibrational spectroscopic characterisation of salmeterol xinafoate polymorphs and a preliminary investigation of their transformation using simultaneous in situ portable Raman spectroscopy and differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Hassan Refat H. [Chemical and Forensic Sciences/University Analytical Centre, School of Life Sciences, University of Bradford, Richmond Road, Bradford BD7 1DP (United Kingdom); Edwards, Howell G.M. [Chemical and Forensic Sciences/University Analytical Centre, School of Life Sciences, University of Bradford, Richmond Road, Bradford BD7 1DP (United Kingdom)], E-mail: H.G.M.Edwards@bradford.ac.uk; Hargreaves, Michael D.; Munshi, Tasnim; Scowen, Ian J.; Telford, Richard J. [Chemical and Forensic Sciences/University Analytical Centre, School of Life Sciences, University of Bradford, Richmond Road, Bradford BD7 1DP (United Kingdom)

    2008-07-14

    Knowledge and control of the polymorphic phases of chemical compounds are important aspects of drug development in the pharmaceutical industry. Salmeterol xinafoate, a long acting {beta}-adrenergic receptor agonist, exists in two polymorphic Forms, I and II. Raman and near infrared spectra were obtained of these polymorphs at selected wavelengths in the range of 488-1064 nm; significant differences in the Raman and near-infrared spectra were apparent and key spectral marker bands have been identified for the vibrational spectroscopic characterisation of the individual polymorphs which were also characterised with X ray diffractometry. The solid-state transition of salmeterol xinafoate polymorphs was studied using simultaneous in situ portable Raman spectroscopy and differential scanning calorimetry isothermally between transitions. This method assisted in the unambiguous characterisation of the two polymorphic forms by providing a simultaneous probe of both the thermal and vibrational data. The study demonstrates the value of a rapid in situ analysis of a drug polymorph which can be of potential value for at-line in-process control.

  7. Vibrational spectroscopic characterisation of salmeterol xinafoate polymorphs and a preliminary investigation of their transformation using simultaneous in situ portable Raman spectroscopy and differential scanning calorimetry

    International Nuclear Information System (INIS)

    Ali, Hassan Refat H.; Edwards, Howell G.M.; Hargreaves, Michael D.; Munshi, Tasnim; Scowen, Ian J.; Telford, Richard J.

    2008-01-01

    Knowledge and control of the polymorphic phases of chemical compounds are important aspects of drug development in the pharmaceutical industry. Salmeterol xinafoate, a long acting β-adrenergic receptor agonist, exists in two polymorphic Forms, I and II. Raman and near infrared spectra were obtained of these polymorphs at selected wavelengths in the range of 488-1064 nm; significant differences in the Raman and near-infrared spectra were apparent and key spectral marker bands have been identified for the vibrational spectroscopic characterisation of the individual polymorphs which were also characterised with X ray diffractometry. The solid-state transition of salmeterol xinafoate polymorphs was studied using simultaneous in situ portable Raman spectroscopy and differential scanning calorimetry isothermally between transitions. This method assisted in the unambiguous characterisation of the two polymorphic forms by providing a simultaneous probe of both the thermal and vibrational data. The study demonstrates the value of a rapid in situ analysis of a drug polymorph which can be of potential value for at-line in-process control

  8. Differential scanning calorimetry of bacteria.

    Science.gov (United States)

    Miles, C A; Mackey, B M; Parsons, S E

    1986-04-01

    Thermograms obtained by differential scanning calorimetry of a range of bacteria of different heat resistances were compared. Equations were derived to calculate the rate at which the numbers of viable organisms in a calorimeter decline as the temperature is raised at a constant rate. Vegetative bacteria scanned at 10 degrees C min-1 showed multi-peaked thermograms with four major peaks (denoted m, n, p and q) occurring in the regions 68-73, 77-84, 89-99 and 105-110 degrees C respectively. Exceptions were that peak m (the largest peak) occurred at 79-82 degrees C in Bacillus stearothermophilus and an additional peak, r, was detected in Escherichia coli at 119 degrees C. At temperatures below the main peak m there were major differences in thermograms between species. There was a direct relationship between the onset of thermal denaturation and the thermoresistance of different organisms. Heat-sensitive organisms displayed thermogram features which were absent in the more heat-resistant types. When samples were cooled to 5 degrees C and re-heated, a small endothermic peak, pr, was observed at the same temperature as p. Peaks p and pr were identified as the melting endotherms of DNA. In all vegetative organisms examined, maximum death rates, computed from published D and z values, occurred at temperatures above the onset of thermal denaturation, i.e. cell death and irreversible denaturation of cell components occurred within the same temperature range.

  9. Proximity Scanning Transmission Electron Microscopy/Spectroscopy

    OpenAIRE

    Hwang, Ing-Shouh

    2016-01-01

    Here a new microscopic method is proposed to image and characterize very thin samples like few-layer materials, organic molecules, and nanostructures with nanometer or sub-nanometer resolution using electron beams of energies lower than 20 eV. The microscopic technique achieves high resolution through the proximity (or near-field) effect, as in scanning tunneling microscopy (STM), while it also allows detection of transmitted electrons for imaging and spectroscopy, as in scanning transmission...

  10. The effect of increasing membrane curvature on the phase transition and mixing behavior of a dimyristoyl-sn-glycero-3-phosphatidylcholine/distearoyl-sn-glycero-3-phosphatidylcholine lipid mixture as studied by Fourier transform infrared spectroscopy and differential scanning calorimetry

    DEFF Research Database (Denmark)

    Brumm, T.; Jørgensen, Kent; Mouritsen, Ole G.

    1996-01-01

    The phase transition behavior of a lipid bilayer of dimyristoyl-sn-glycero-3-phosphalidylcholine/distearoyl-sn- glycero-3-phosphatidylcholine (DMPC-d54/DSPC) (1:1) on a solid support with varying curvatures was investigated with differential scanning calorimetry, infrared spectroscopy, and model...... of the liquidus point can be understood as a reduction of the lateral pressure in the bilayer with increasing curvature. The shift of the solidus line is interpreted as a result of the increased demixing of the two components in the two-phase region with increasing curvature due to lowering of the lateral...

  11. A comprehensive physicochemical, thermal, and spectroscopic characterization of zinc (II) chloride using X-ray diffraction, particle size distribution, differential scanning calorimetry, thermogravimetric analysis/differential thermogravimetric analysis, ultraviolet-visible, and Fourier transform-infrared spectroscopy.

    Science.gov (United States)

    Trivedi, Mahendra Kumar; Sethi, Kalyan Kumar; Panda, Parthasarathi; Jana, Snehasis

    2017-01-01

    Zinc chloride is an important inorganic compound used as a source of zinc and has other numerous industrial applications. Unfortunately, it lacks reliable and accurate physicochemical, thermal, and spectral characterization information altogether. Hence, the authors tried to explore in-depth characterization of zinc chloride using the modern analytical technique. The analysis of zinc chloride was performed using powder X-ray diffraction (PXRD), particle size distribution, differential scanning calorimetry (DSC), thermogravimetric analysis/differential thermogravimetric analysis (TGA/DTG), ultraviolet-visible spectroscopy (UV-vis), and Fourier transform-infrared (FT-IR) analytical techniques. The PXRD patterns showed well-defined, narrow, sharp, and the significant peaks. The crystallite size was found in the range of 14.70-55.40 nm and showed average crystallite size of 41.34 nm. The average particle size was found to be of 1.123 ( d 10 ), 3.025 ( d 50 ), and 6.712 ( d 90 ) μm and average surface area of 2.71 m 2 /g. The span and relative span values were 5.849 μm and 1.93, respectively. The DSC thermogram showed a small endothermic inflation at 308.10°C with the latent heat (ΔH) of fusion 28.52 J/g. An exothermic reaction was observed at 449.32°C with the ΔH of decomposition 66.10 J/g. The TGA revealed two steps of the thermal degradation and lost 8.207 and 89.72% of weight in the first and second step of degradation, respectively. Similarly, the DTG analysis disclosed T max at 508.21°C. The UV-vis spectrum showed absorbance maxima at 197.60 nm (λ max ), and FT-IR spectrum showed a peak at 511/cm might be due to the Zn-Cl stretching. These in-depth, comprehensive data would be very much useful in all stages of nutraceuticals/pharmaceuticals formulation research and development and other industrial applications.

  12. Polarized differential-phase laser scanning microscope

    International Nuclear Information System (INIS)

    Chou Chien; Lyu, C.-W.; Peng, L.-C.

    2001-01-01

    A polarized differential-phase laser scanning microscope, which combines a polarized optical heterodyne Mach-Zehnder interferometer and a differential amplifier to scan the topographic image of a surface, is proposed. In the experiment the differential amplifier, which acts as a PM-AM converter, in the experiment, converting phase modulation (PM) into amplitude modulation (AM). Then a novel, to our knowledge, phase demodulator was proposed and implemented for the differential-phase laser scanning microscope. An optical grating (1800 lp/mm) was imaged. The lateral and the depth resolutions of the imaging system were 0.5 μm and 1 nm, respectively. The detection accuracy, which was limited by the reflectivity variation of the test surface, is discussed

  13. Characterization of Temperature Induced Phase Transitions in the Five Polymorphic Forms of Sulfathia-zole by Terahertz Pulsed Spectroscopy and Differential Scanning Calorimetry

    DEFF Research Database (Denmark)

    Zeitler, J. Axel; Newnham, David A.; Taday, Philip F.

    2006-01-01

    The far-infrared properties of all five described polymorphic forms of the drug sulfathiazole have been studied by terahertz pulsed spectroscopy and low frequency Raman spectroscopy. The spectra of the different polymorphs are distinctly different. Terahertz pulsed spectroscopy proves to be a rapid...

  14. Comparison of macromolecular interactions in the cell walls of hardwood, softwood and maize by fluorescence and FTIR spectroscopy, differential polarization laser scanning microscopy and X-ray diffraction

    Czech Academy of Sciences Publication Activity Database

    Djikanović, D.; Devecerski, A.; Steinbach, Gabor; Simonović, J.; Matović, B.; Garab, G.; Kalauzi, A.; Radotić, K.

    2016-01-01

    Roč. 50, č. 3 (2016), s. 547-566 ISSN 0043-7719 Institutional support: RVO:61388971 Keywords : IR SPECTROSCOPY * CROSS-LINKING * CELLULOSE Subject RIV: EE - Microbiology, Virology Impact factor: 1.509, year: 2016

  15. Differential scanning microcalorimetry of intrinsically disordered proteins.

    Science.gov (United States)

    Permyakov, Sergei E

    2012-01-01

    Ultrasensitive differential scanning calorimetry (DSC) is an indispensable thermophysical technique enabling to get direct information on enthalpies accompanying heating/cooling of dilute biopolymer solutions. The thermal dependence of protein heat capacity extracted from DSC data is a valuable source of information on intrinsic disorder level of a protein. Application details and limitations of DSC technique in exploration of protein intrinsic disorder are described.

  16. High-pressure differential scanning microcalorimeter.

    Science.gov (United States)

    Senin, A A; Dzhavadov, L N; Potekhin, S A

    2016-03-01

    A differential scanning microcalorimeter for studying thermotropic conformational transitions of biopolymers at high pressure has been designed. The calorimeter allows taking measurements of partial heat capacity of biopolymer solutions vs. temperature at pressures up to 3000 atm. The principles of operation of the device, methods of its calibration, as well as possible applications are discussed.

  17. The effect of electron irradiation on high-density polyethylene: Positron annihilation lifetime spectroscopy, differential scanning calorimetry and X-ray scattering studies

    Energy Technology Data Exchange (ETDEWEB)

    Zaydouri, A. [Laboratoire de Chimie-Physique et Rayonnement-Alain Chambaudet, UMR CEA E4, Universite de Franche Comte, 16 route de Gray, 25030 Besancon Cedex (France)], E-mail: zaydouri@hotmail.com; Grivet, M. [Laboratoire de Chimie-Physique et Rayonnement-Alain Chambaudet, UMR CEA E4, Universite de Franche Comte, 16 route de Gray, 25030 Besancon Cedex (France)], E-mail: manuel.grivet@univ-fcomte.fr

    2009-09-15

    Electron irradiation effects in HDPE have been studied using positron annihilation lifetime spectroscopy. In the four-component analysis of a spectrum, two long-lived states are ascribed to ortho-positronium (o-Ps) annihilation in the crystalline phase and in the amorphous phase. The study of the o-Ps parameters highlights the different behaviour of the two phases. From the o-Ps lifetime in the crystalline phase, it is shown that the effect of irradiation is larger at 250 kGy. Thermal analysis (DSC) reveals two different melting temperatures and also an increase in the fusion enthalpy, at 250 kGy. This phenomenon induced by an electron beam is erased by thermal treatment: fusion and re-crystallisation. However, before and after thermal treatment no changes are observed in the crystallite size and in the crystalline rate using wide-angle X-ray scattering.

  18. Scanning tunneling spectroscopy of Pb thin films

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Michael

    2010-12-13

    The present thesis deals with the electronic structure, work function and single-atom contact conductance of Pb thin films, investigated with a low-temperature scanning tunneling microscope. The electronic structure of Pb(111) thin films on Ag(111) surfaces is investigated using scanning tunneling spectroscopy (STS). Quantum size effects, in particular, quantum well states (QWSs), play a crucial role in the electronic and physical properties of these films. Quantitative analysis of the spectra yields the QWS energies as a function of film thickness, the Pb bulk-band dispersion in {gamma}-L direction, scattering phase shifts at the Pb/Ag interface and vacuum barrier as well as the lifetime broadening at anti {gamma}. The work function {phi} is an important property of surfaces, which influences catalytic reactivity and charge injection at interfaces. It controls the availability of charge carriers in front of a surface. Modifying {phi} has been achieved by deposition of metals and molecules. For investigating {phi} at the atomic scale, scanning tunneling microscopy (STM) has become a widely used technique. STM measures an apparent barrier height {phi}{sub a}, which is commonly related to the sample work function {phi}{sub s} by: {phi}{sub a}=({phi}{sub s}+{phi}{sub t}- vertical stroke eV vertical stroke)/2, with {phi}{sub t} the work function of the tunneling tip, V the applied tunneling bias voltage, and -e the electron charge. Hence, the effect of the finite voltage in STM on {phi}{sub a} is assumed to be linear and the comparison of {phi}{sub a} measured at different surface sites is assumed to yield quantitative information about work function differences. Here, the dependence of {phi}{sub a} on the Pb film thickness and applied bias voltage V is investigated. {phi}{sub a} is found to vary significantly with V. This bias dependence leads to drastic changes and even inversion of contrast in spatial maps of {phi}{sub a}, which are related to the QWSs in the Pb

  19. Differential Aging Signals in Abdominal CT Scans.

    Science.gov (United States)

    Orlov, Nikita V; Makrogiannis, Sokratis; Ferrucci, Luigi; Goldberg, Ilya G

    2017-12-01

    Changes in the composition of body tissues are major aging phenotypes, but they have been difficult to study in depth. Here we describe age-related change in abdominal tissues observable in computed tomography (CT) scans. We used pattern recognition and machine learning to detect and quantify these changes in a model-agnostic fashion. CT scans of abdominal L4 sections were obtained from Baltimore Longitudinal Study of Aging (BLSA) participants. Age-related change in the constituent tissues were determined by training machine classifiers to differentiate age groups within male and female strata ("Younger" at 50-70 years old vs "Older" at 80-99 years old). The accuracy achieved by the classifiers in differentiating the age cohorts was used as a surrogate measure of the aging signal in the different tissues. The highest accuracy for discriminating age differences was 0.76 and 0.72 for males and females, respectively. The classification accuracy was 0.79 and 0.71 for adipose tissue, 0.70 and 0.68 for soft tissue, and 0.65 and 0.64 for bone. Using image data from a large sample of well-characterized pool of participants dispersed over a wide age range, we explored age-related differences in gross morphology and texture of abdominal tissues. This technology is advantageous for tracking effects of biological aging and predicting adverse outcomes when compared to the traditional use of specific molecular biomarkers. Application of pattern recognition and machine learning as a tool for analyzing medical images may provide much needed insight into tissue changes occurring with aging and, further, connect these changes with their metabolic and functional consequences. Published by Elsevier Inc.

  20. Full information acquisition in scanning probe microscopy and spectroscopy

    Science.gov (United States)

    Jesse, Stephen; Belianinov, Alex; Kalinin, Sergei V.; Somnath, Suhas

    2017-04-04

    Apparatus and methods are described for scanning probe microscopy and spectroscopy based on acquisition of full probe response. The full probe response contains valuable information about the probe-sample interaction that is lost in traditional scanning probe microscopy and spectroscopy methods. The full probe response is analyzed post data acquisition using fast Fourier transform and adaptive filtering, as well as multivariate analysis. The full response data is further compressed to retain only statistically significant components before being permanently stored.

  1. Scanning Angle Raman spectroscopy in polymer thin film characterization

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Vy H.T. [Iowa State Univ., Ames, IA (United States)

    2015-12-19

    The focus of this thesis is the application of Raman spectroscopy for the characterization of thin polymer films. Chapter 1 provides background information and motivation, including the fundamentals of Raman spectroscopy for chemical analysis, scanning angle Raman scattering and scanning angle Raman scattering for applications in thin polymer film characterization. Chapter 2 represents a published manuscript that focuses on the application of scanning angle Raman spectroscopy for the analysis of submicron thin films with a description of methodology for measuring the film thickness and location of an interface between two polymer layers. Chapter 3 provides an outlook and future directions for the work outlined in this thesis. Appendix A, contains a published manuscript that outlines the use of Raman spectroscopy to aid in the synthesis of heterogeneous catalytic systems. Appendix B and C contain published manuscripts that set a foundation for the work presented in Chapter 2.

  2. Scanning tunneling spectroscopy study of DNA conductivity

    Czech Academy of Sciences Publication Activity Database

    Kratochvílová, Irena; Král, Karel; Bunček, M.; Nešpůrek, Stanislav; Todorciuc, Tatiana; Weiter, M.; Navrátil, J.; Schneider, Bohdan; Pavluch, J.

    2008-01-01

    Roč. 6, č. 3 (2008), s. 422-426 ISSN 1895-1082 R&D Projects: GA AV ČR KAN401770651; GA MŠk OC 137; GA AV ČR KAN400720701; GA AV ČR KAN200100801 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z40500505; CEZ:AV0Z40550506 Keywords : molecular electronics * DNA * scanning tunneling microscopy * conductivity * charge carrier transport Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.448, year: 2008

  3. Quantitative determination of two polymorphic forms of imatinib mesylate in a drug substance and tablet formulation by X-ray powder diffraction, differential scanning calorimetry and attenuated total reflectance Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Bellur Atici, Esen; Karlığa, Bekir

    2015-10-10

    Imatinib has been identified as a tyrosine kinase inhibitor that selectively inhibits the Abl tyrosine kinases, including Bcr-Abl. The active substance used in drug product is the mesylate salt form of imatinib, a phenylaminopyrimidine derivative and chemically named as N-(3-(4-(pyridin-3-yl) pyrimidin-2-ylamino)-4-methylphenyl)-4-((4-methylpiperazin-1-yl) methyl)-benzamide methanesulfonic acid salt. It exhibits many polymorphic forms and most stable and commercialized polymorphs are known as α and β forms. Molecules in α and β polymorphic forms exhibit significant conformational differences due to their different intra- and intermolecular interactions, which stabilize their molecular conformations and affect their physicochemical properties such as bulk density, melting point, solubility, stability, and processability. The manufacturing process of a drug tablet included granulation, compression, coating, and drying may cause polymorphic conversions. Therefore, polymorphic content of the drug substance should be controlled during quality control and stability testing. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD) methods were evaluated for determination of the polymorphic content of the drug substance and drug product; and PXRD was the most accurate technique and selected as preferred method and validated. Prior to development of a quantification method, pure α and β polymorphs were characterized and used throughout the method development and validation studies. Mixtures with different ratios of α and β forms were scanned using X-ray diffractometer with a scan rate of 0.250°/min over an angular range of 19.5-21.0° 2θ and the peak heights for characteristic peak of β form at 20.5 ± 0.2° 2θ diffraction angle were used to generate a calibration curve. The detection limit of β polymorph in α form imatinib mesylate tablets was found as 4% and

  4. Use of thermal analysis coupled with differential scanning calorimetry, quadrupole mass spectrometry and infrared spectroscopy (TG-DSC-QMS-FTIR to monitor chemical properties and thermal stability of fulvic and humic acids.

    Directory of Open Access Journals (Sweden)

    Patrycja Boguta

    Full Text Available Thermogravimetry-coupled with differential scanning calorimetry, quadrupole mass spectrometry, and Fourier-transform infrared spectroscopy (TG-DSC-QMS-FTIR-was applied to monitor the thermal stability (in an N2 pyrolytic atmosphere and chemical properties of natural polymers, fulvic (FA and humic acids (HA, isolated from chemically different soils. Three temperature ranges, R1, 40-220°C; R2, 220-430°C; and R3, 430-650°C, were distinguished from the DSC data, related to the main thermal processes of different structures (including transformations without weight loss. Weight loss (ΔM estimated from TG curves at the above temperature intervals revealed distinct differences within the samples in the content of physically adsorbed water (at R1, volatile and labile functional groups (at R2 as well as recalcitrant and refractory structures (at R3. QMS and FTIR modules enabled the chemical identification (by masses and by functional groups, respectively of gaseous species evolved during thermal decomposition at R1, R2 and R3. Variability in shape, area and temperature of TG, DSC, QMS and FTIR peaks revealed differences in thermal stability and chemical structure of the samples between the FAs and HAs fractions of different origin. The statistical analysis showed that the parameters calculated from QMS (areas of m/z = 16, 17, 18, 44, DSC (MaxDSC and TG (ΔM at R1, R2 and R3 correlated with selected chemical properties of the samples, such as N, O and COOH content as well as E2/E6 and E2/E4 indexes. This indicated a high potential for the coupled method to monitor the chemical changes of humic substances. A new humification parameter, HTD, based on simple calculations of weight loss at specific temperature intervals proved to be a good alternative to indexes obtained from other methods. The above findings showed that the TG-DSC-QMS-FTIR coupled technique can represent a useful tool for the comprehensive assessment of FAs and HAs properties related to

  5. Use of thermal analysis coupled with differential scanning calorimetry, quadrupole mass spectrometry and infrared spectroscopy (TG-DSC-QMS-FTIR) to monitor chemical properties and thermal stability of fulvic and humic acids.

    Science.gov (United States)

    Boguta, Patrycja; Sokołowska, Zofia; Skic, Kamil

    2017-01-01

    Thermogravimetry-coupled with differential scanning calorimetry, quadrupole mass spectrometry, and Fourier-transform infrared spectroscopy (TG-DSC-QMS-FTIR)-was applied to monitor the thermal stability (in an N2 pyrolytic atmosphere) and chemical properties of natural polymers, fulvic (FA) and humic acids (HA), isolated from chemically different soils. Three temperature ranges, R1, 40-220°C; R2, 220-430°C; and R3, 430-650°C, were distinguished from the DSC data, related to the main thermal processes of different structures (including transformations without weight loss). Weight loss (ΔM) estimated from TG curves at the above temperature intervals revealed distinct differences within the samples in the content of physically adsorbed water (at R1), volatile and labile functional groups (at R2) as well as recalcitrant and refractory structures (at R3). QMS and FTIR modules enabled the chemical identification (by masses and by functional groups, respectively) of gaseous species evolved during thermal decomposition at R1, R2 and R3. Variability in shape, area and temperature of TG, DSC, QMS and FTIR peaks revealed differences in thermal stability and chemical structure of the samples between the FAs and HAs fractions of different origin. The statistical analysis showed that the parameters calculated from QMS (areas of m/z = 16, 17, 18, 44), DSC (MaxDSC) and TG (ΔM) at R1, R2 and R3 correlated with selected chemical properties of the samples, such as N, O and COOH content as well as E2/E6 and E2/E4 indexes. This indicated a high potential for the coupled method to monitor the chemical changes of humic substances. A new humification parameter, HTD, based on simple calculations of weight loss at specific temperature intervals proved to be a good alternative to indexes obtained from other methods. The above findings showed that the TG-DSC-QMS-FTIR coupled technique can represent a useful tool for the comprehensive assessment of FAs and HAs properties related to their

  6. Study on Differential Optical Absorption Spectroscopy : Technique and its Applications

    OpenAIRE

    Liu, Jianguo

    2002-01-01

    ln the first part of speech, with a description of the principle of DOAS (Differential Optical Absorption Spectroscopy), the design and realization of two different kinds of DOAS systems are nresented. 0ne is using a slotted disc raoid scanning device with a photomultiplier, which is suitable for ambient air quality measurement. It can measure total 16 kinds of pollutants such as SO_2, NO, N02, NH_3, O_3, C_6H_6, C_7H_8 and CH_2O etc., with detection limits of 1-2ppb. The other is using a UV ...

  7. Usefulness of Thallium Scan for Differential Diagnosis of Breast Mass

    International Nuclear Information System (INIS)

    Bae, Sang Kyun; Yum, Ha Yong; Lee, Chung Han; Choi, Kyung Hyun

    1994-01-01

    The purpose of this study is to evaluate thallium scanning as a potential test in differentiating malignant from benign lesions of breast. Thirty-one female patients underwent thallium scan of the breast. After intravenous injection of 74-111 MBq(2-3 mCi)of thallium-201, anterior and lateral images were obtained. We compared thallium scans with pathological results. Of 11 patients with breast cancers, 10 cases (90.9%) were detected using thallium scan. Thallium scan obtained in one patient who had breast cancer but received several cycles of chemotherapy did not show thallium uptake. The smallest detectable cancer was 1.5 cm in diameter. In contrast, there is no thallium accumulation in breasts of 17 of 20 patients with benign disease (85%), Three cases of 13 fibrocystic disease show thallium uptake in their breast. In conclusion, thallium scan is an effective test in differentiating benign from malignant lesion.

  8. Scanning tunneling spectroscopy on electron-boson interactions in superconductors

    CERN Document Server

    Schackert, Michael Peter

    2015-01-01

    This work describes the experimental study of electron-boson interactions in superconductors by means of inelastic electron tunneling spectroscopy performed with a scanning tunneling microscope (STM) at temperatures below 1 K. This new approach allows the direct measurement of the Eliashberg function of conventional superconductors as demonstrated on lead (Pb) and niobium (Nb). Preparative experiments on unconventional iron-pnictides are presented in the end.

  9. Quantitative fluorescence spectroscopy in turbid media using fluorescence differential path length spectroscopy

    NARCIS (Netherlands)

    Amelink, Arjen; Kruijt, Bastiaan; Robinson, Dominic J.; Sterenborg, Henricus J. C. M.

    2008-01-01

    We have developed a new technique, fluorescence differential path length spectroscopy (FDPS), that enables the quantitative investigation of fluorophores in turbid media. FDPS measurements are made with the same probe geometry as differential path length spectroscopy (DPS) measurements. Phantom

  10. Scanning, non-contact, hybrid broadband diffuse optical spectroscopy and diffuse correlation spectroscopy system

    OpenAIRE

    Johansson, Johannes D.; Mireles, Miguel; Morales-Dalmau, Jordi; Farzam, Parisa; Martínez-Lozano, Mar; Casanovas, Oriol; Durduran, Turgut

    2016-01-01

    A scanning system for small animal imaging using non-contact, hybrid broadband diffuse optical spectroscopy (ncDOS) and diffuse correlation spectroscopy (ncDCS) is presented. The ncDOS uses a two-dimensional spectrophotometer retrieving broadband (610-900 nm) spectral information from up to fifty-seven source-detector distances between 2 and 5 mm. The ncDCS data is simultaneously acquired from four source-detector pairs. The sample is scanned in two dimensions while tracking variations in hei...

  11. Design of Test Wrapper Scan Chain Based on Differential Evolution

    Directory of Open Access Journals (Sweden)

    Aijun Zhu

    2013-08-01

    Full Text Available Integrated Circuit has entered the era of design of the IP-based SoC (System on Chip, which makes the IP core reuse become a key issue. SoC test wrapper design for scan chain is a NP Hard problem, we propose an algorithm based on Differential Evolution (DE to design wrapper scan chain. Through group’s mutation, crossover and selection operations, the design of test wrapper scan chain is achieved. Experimental verification is carried out according to the international standard benchmark ITC’02. The results show that the algorithm can obtain shorter longest wrapper scan chains, compared with other algorithms.

  12. Can magnetic resonance spectroscopy differentiate endometrial cancer?

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jie; Cai, Shifeng; Han, Xue; Liu, Qingwei; Xin, Yinghui [Shandong University, Department of Radiology, Shandong Provincial Hospital, Jinan (China); Li, Changzhong; Yang, Chunrun [Shandong University, Department of Obstetrics and Gynecology, Shandong Provincial Hospital, Jinan (China); Sun, Xichao; Zong, Yuanyuan [Shandong University, Department of Pathology, Shandong Provincial Hospital, Jinan (China); Fu, Caixia [Siemens Shenzhen Magnetic Resonance Ltd., Siemens MRI Center, Shenzhen (China)

    2014-10-15

    To investigate whether the choline-containing compounds (Cho) obtained from three-dimensional {sup 1}H magnetic resonance (MR) spectroscopy can differentiate endometrial cancer (ECa) from benign lesions in endometria or in submucosa (BLs-ESm) and is associated with the aggressiveness of ECa. Fifty-seven patients (ECa, 38; BLs-ESm, 19) underwent preoperative multi-voxel MR spectroscopy at 3.0 T. The ratio of the sum of the Cho peak integral to the sum of the unsuppressed water peak integral (Cho/water) and the coefficient of variation (CV) used to describe the variability of Cho/water in one lesion were calculated. Mean Cho/water (±standard deviation [SD]) was (3.02 ± 1.43) x 10{sup -3} for ECa and (1.68 ± 0.33) x 10{sup -3} for BLs-ESm (p < 0.001). Mean Cho/water was (4.42 ± 1.53) x 10{sup -3} for type II ECa and (2.65 ± 1.17) x 10{sup -3} for type I ECa (p = 0.001). There were no significant differences among different stages of ECa (p = 0.107) or different grades of ECa (p = 0.142). The Cho/water was positively correlated with tumour stage (r = 0.386, p = 0.017) and size (r = 0.333, p = 0.041). The CV was also positively correlated with tumour stage (r = 0.537, p = 0.001) and size (r = 0.34, p = 0.037). The Cho/water can differentiate ECa from BLs-ESm and differentiate type II from type I ECa, but cannot differentiate different stages of ECa or different grades of ECa. Cho/water increased with the increase of tumour stage and size. (orig.)

  13. Scanning ion deep level transient spectroscopy: I. Theory

    International Nuclear Information System (INIS)

    Laird, J S; Jagadish, C; Jamieson, D N; Legge, G J F

    2006-01-01

    Theoretical aspects of a new technique for the MeV ion microbeam are described in detail for the first time. The basis of the technique, termed scanning ion deep level transient spectroscopy (SIDLTS), is the imaging of defect distributions within semiconductor devices. The principles of SIDLTS are similar to those behind other deep level transient spectroscopy (DLTS) techniques with the main difference stemming from the injection of carriers into traps using the localized energy-loss of a focused MeV ion beam. Energy-loss of an MeV ion generates an electron-hole pair plasma, providing the equivalent of a DLTS trap filling pulse with a duration which depends on space-charge screening of the applied electric field and ambipolar erosion of the plasma for short ranging ions. Some nanoseconds later, the detrapping current transient is monitored as a charge transient. Scanning the beam in conjunction with transient analysis allows the imaging of defect levels. As with DLTS, the temperature dependence of the transient can be used to extract trap activation levels. In this, the first of a two-part paper, we introduce the various stages of corner capture and derive a simple expression for the observed charge transient. The second paper will illustrate the technique on a MeV ion implanted Au-Si Schottky junction

  14. Differential scanning calorimetric and powder X-ray diffraction ...

    Indian Academy of Sciences (India)

    The thermotropic phase transitions and supramolecular structure of NAAEs were investigated by differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). Results obtained from DSC studies indicate that the transition temperatures (t), enthalpies ( t) and entropies ( t) exhibit odd-even alternation ...

  15. Differential scanning fluorimetry illuminates silk feedstock stability and processability

    Czech Academy of Sciences Publication Activity Database

    Dicko, C.; Kasoju, Naresh; Hawkins, N.; Vollrath, F.

    2016-01-01

    Roč. 12, č. 1 (2016), s. 255-262 ISSN 1744-683X R&D Projects: GA MŠk(CZ) EE2.3.30.0029 Institutional support: RVO:61389013 Keywords : differential scanning fluorimetry * biomaterials * silk fibroin Subject RIV: CE - Biochemistry Impact factor: 3.889, year: 2016

  16. Probing Nanoscale Electronic and Magnetic Interaction with Scanning Tunneling Spectroscopy

    DEFF Research Database (Denmark)

    Bork, Jakob

    This thesis is concerned with fundamental research into electronic and magnetic interaction on the nanoscale. From small metallic and magnetic islands and layers to single atoms. The research revolves around magnetic interaction probed through the spectroscopic capabilities of the scanning....... This is related to research in correlated electron materials such as studies of phase transitions in heavy fermion compounds and magnetic interaction in spintronic research. The capping of cobalt islands on Cu(111) with silver is investigated with STM and photoemission spectroscopy. It is shown that at low...... coverage the silver preferably nucleates on top of the bilayer high cobalt islands compared to directly on the Cu(111) substrate. Furthermore, the silver forms a combination of a reconstruction and a Moire pattern which is investigated with low-energy electron diraction and spectroscopic STM mapping at 6...

  17. Evaluation of aluminosilicate glass sintering during differential scanning calorimetry

    International Nuclear Information System (INIS)

    Souza, Juliana Pereira de

    2015-01-01

    In this work a difference in the baseline in differential scanning calorimetry analyses, observed in a work where aluminosilicate glasses microspheres containing Ho were studied for application in selective internal radiotherapy as hepatocellular carcinoma treatment, was studied. The glasses with nominal composition 53,7 SiO 2 .10,5 Al 2 O 3 . 35,8 MgO in %mol were produced from traditional melting. The first obtained were milled and sieved in the range of 45 a 63 μm. The material was used to produce glass microspheres by the gravitational fall method. The glass powder and the microspheres were characterized by X ray fluorescence spectrometry, laser diffraction, X ray diffraction, differential scanning calorimetry, differential thermal analysis, thermogravimetry, mass spectrometry, and scanning electron microscopy. After the thermal analyses, pellets were formed in the crucibles and were analyzed by scanning electron microscopy, X ray diffraction, and He pycnometry. The difference in the baseline was associated to the viscous flow sintering process and happens because of the decrease in the detected heat flow due to the sample shrinkage. Other events as concurrent crystallization with the sintering process were also studied. (author)

  18. Simultaneous reference and differential waveform acquisition in time-resolved terahertz spectroscopy

    DEFF Research Database (Denmark)

    Iwaszczuk, Krzysztof; Cooke, David; Fujiwara, Masazumi

    2009-01-01

    We present a new method for data acquisition in time-resolved terahertz spectroscopy experiments. Our approach is based on simultaneous collection of reference and differential THz scans. Both the optical THz generation beam and the pump beam are modulated at two different frequencies that are no...

  19. Laser Ultrasound Spectroscopy Scanning for 3D Printed Parts

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, Guendalyn Kendra [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-04

    One of the challenges of additive manufacturing is quality control due to the possibility of unseen flaws in the final product. The current methods of inspection are lacking in detail, too slow for practical use, or unable to validate internal structure. This report examines the use of laser ultrasound spectroscopy in layer by layer scans of 3D printed parts as they are created. The result is fast and detailed quality control. An additional advantage of this method is the ability to cancel a print as soon as a defect is detected, therefore saving materials and time. This technique, though simple in concept, has been a challenge to implement. I discuss tweaking the 3D printer configuration, and finding the optimal settings for laser scanning small parts made of ABS plastic, as well as the limits of how small of a detail the laser can detect. These settings include the frequency of the ultrasonic transducer, the speed of the laser, and the distance from the laser to the part.

  20. Fast differential scanning calorimetry of liquid samples with chips

    DEFF Research Database (Denmark)

    Splinter, R.; van Herwaarden, A. W.; van Wetten, I. A.

    2015-01-01

    Based on a modified version of standard chips for fast differential scanning calorimetry, DSC of liquid samples has been performed at temperature scan rates of up to 1000 °C/s. This paper describes experimental results with the protein lysozyme, bovine serum, and olive oil. The heating and cooling....... The bovine serum measurements show two main peaks, in good agreement with standard DSC measurements. Olive oil has been measured, with good agreement for the cooling curve and qualitative agreement for the heater curve, compared to DSC measurements....

  1. Thermally processed titanium oxides film on Si(0 0 1) surface studied with scanning tunneling microscopy/spectroscopy

    International Nuclear Information System (INIS)

    Aoki, T.; Shudo, K.; Sato, K.; Ohno, S.; Tanaka, M.

    2010-01-01

    Thermal structural changes of TiO x films built on a Si(0 0 1) surface were investigated at the nanometer scale with scanning tunneling microscopy. Electronic properties of individual clusters were classified by means of scanning tunneling spectroscopy. The differential conductance (dI/dV) near the Fermi energy showed that nano-clusters were transformed from semiconducting Ti-silicates into metallic Ti-silicides after heating to 970 K. Peaks of normalized differential conductance (dI/dV/(I/V)) of the clusters shifted after heating to about 1070 K, indicating exclusion of oxygen from the clusters.

  2. Scanning tunneling microscopy and spectroscopy of phase change alloys

    Energy Technology Data Exchange (ETDEWEB)

    Subramaniam, Dinesh; Pauly, Christian; Pratzer, Marco; Liebmann, Marcus; Morgenstern, Markus [II. Physikalisches Institut B, RWTH Aachen (Germany); Rausch, Pascal; Woda, Michael; Wuttig, Matthias [I. Physikalisches Institut A, RWTH Aachen (Germany)

    2009-07-01

    Phase change random access memory (PCRAM) is a very promising candidate for the next generation of memories. In contrast to the standard Si-based RAM, PCRAM is a non-volatile storage system which exploits the high electrical contrast between the amorphous and the crystalline phase. However, the origin of this contrast is not well understood. Scanning tunneling microscopy gives insight into the local atomic structure and the electronic properties of phase change materials. Using the topography mode of STM, we realized images of Ge{sub 1}Sb{sub 2}Te{sub 4} on the nanometer down to the atomic scale, revealing the morphology as well as the complex atomic arrangement of the sputter-deposited material. The spectroscopy mode enabled us to analyse the local density of states in the amorphous and crystalline phase. The band gap varied continuously from 0.5 eV in the amorphous phase to 0.2 eV in the crystalline phase. The Fermi level moved from the center of the gap in the amorphous phase into the valence band within the crystalline phase.

  3. Review of MEMS differential scanning calorimetry for biomolecular study

    Science.gov (United States)

    Yu, Shifeng; Wang, Shuyu; Lu, Ming; Zuo, Lei

    2017-12-01

    Differential scanning calorimetry (DSC) is one of the few techniques that allow direct determination of enthalpy values for binding reactions and conformational transitions in biomolecules. It provides the thermodynamics information of the biomolecules which consists of Gibbs free energy, enthalpy and entropy in a straightforward manner that enables deep understanding of the structure function relationship in biomolecules such as the folding/unfolding of protein and DNA, and ligand bindings. This review provides an up to date overview of the applications of DSC in biomolecular study such as the bovine serum albumin denaturation study, the relationship between the melting point of lysozyme and the scanning rate. We also introduce the recent advances of the development of micro-electro-mechanic-system (MEMS) based DSCs.

  4. Applications of modulated differential scanning calorimetry in preformulation studies.

    Science.gov (United States)

    Rabel, S R; Jona, J A; Maurin, M B

    1999-11-01

    Characterization of the thermal properties of active pharmaceutical ingredients is critical in the selection of appropriate physical forms for development and defining proper manufacturing, handling and storage conditions of those chemical entities. Modulated differential scanning calorimetry (MDSC) has proven to be an effective tool in the thorough characterization of thermal behavior of compounds in preformulation studies. Selected applications of MDSC for various preclinical compounds are presented, thereby demonstrating the utility of this analytical method in the determination of glass transitions, characterization of desolvation and degradation processes as well as in the study of polymorphic transformations and crystallizations.

  5. An autosampling differential scanning calorimeter instrument for studying molecular interactions.

    Science.gov (United States)

    Plotnikov, Valerian; Rochalski, Andrew; Brandts, Michael; Brandts, John F; Williston, Samuel; Frasca, Verna; Lin, Lung-Nan

    2002-11-01

    A new ultrasensitive differential scanning calorimeter (DSC) instrument is described, which utilizes autosampling for continuous operation. High scanning rates to 250 deg/h with rapid cooling and equilibration between scans facilitates higher sample throughput up to 50 samples during each 24 h of unattended operation. The instrument is suited for those pharmaceutical applications where higher throughput is important, such as screening drug candidates for binding constant or screening solution conditions for stability of liquid protein formulations. Results are presented on the binding of five different anionic inhibitors to ribonuclease A, which included cytidine 2'-monophosphate (2'CMP), 3'CMP, uridine 3'-monophosphate, pyrophosphate, and phosphate. Binding constants K(B) (or dissociation constants K(d)) are obtained from the shift in the transition temperature T(M) for ribonuclease thermal unfolding in the presence of ligand relative to the transition temperature in the absence of ligand. Measured binding constants ranged from 155 M(-1) (K(d) = 6.45 mM) for the weak-binding phosphate anion to 13100 M(-1) (K(d) = 76.3 microM) for the strongest binding ligand, 2'CMP. The DSC method for measuring binding constants can also be extended to ultratight interactions involving either ligand-protein or protein-protein binding.

  6. Scanning differential polarization microscope: Its use to image linear and circular differential scattering

    International Nuclear Information System (INIS)

    Mickols, W.; Maestre, M.F.

    1988-01-01

    A differential polarization microscope that couples the sensitivity of single-beam measurement of circular dichroism and circular differential scattering with the simultaneous measurement of linear dichroism and linear differential scattering has been developed. The microscope uses a scanning microscope stage and single-point illumination to give the very shallow depth of field found in confocal microscopy. This microscope can operate in the confocal mode as well as in the near confocal condition that can allow one to program the coherence and spatial resolution of the microscope. This microscope has been used to study the change in the structure of chromatin during the development of sperm in Drosophila

  7. Differential scanning calorimetry predicts the critical quality attributes of amorphous glibenclamide

    DEFF Research Database (Denmark)

    Mah, Pei T; Laaksonen, Timo; Rades, Thomas

    2015-01-01

    Selection of a crystallinity detection tool that is able to predict the critical quality attributes of amorphous formulations is imperative for the development of process control strategies. The main aim of this study was to determine the crystallinity detection tool that best predicts the critical...... quality attributes (i.e. physical stability and dissolution behaviour) of amorphous material. Glibenclamide (model drug) was milled for various durations using a planetary mill and characterised using Raman spectroscopy and differential scanning calorimetry (DSC). Physical stability studies upon storage...... and plateaus were reached after milling for certain periods of time (physical stability - 150min; dissolution - 120min). The residual crystallinity which was detectable with DSC (onset of crystallisation), but not with Raman spectroscopy, adversely affected the critical quality attributes of milled...

  8. Rapid-scan Fourier-transform coherent anti-Stokes Raman scattering spectroscopy with heterodyne detection.

    Science.gov (United States)

    Hiramatsu, Kotaro; Luo, Yizhi; Ideguchi, Takuro; Goda, Keisuke

    2017-11-01

    High-speed Raman spectroscopy has become increasingly important for analyzing chemical dynamics in real time. To address the need, rapid-scan Fourier-transform coherent anti-Stokes Raman scattering (FT-CARS) spectroscopy has been developed to realize broadband CARS measurements at a scan rate of more than 20,000 scans/s. However, the detection sensitivity of FT-CARS spectroscopy is inherently low due to the limited number of photons detected during each scan. In this Letter, we show our experimental demonstration of enhanced sensitivity in rapid-scan FT-CARS spectroscopy by heterodyne detection. Specifically, we implemented heterodyne detection by superposing the CARS electric field with an external local oscillator (LO) for their interference. The CARS signal was amplified by simply increasing the power of the LO without the need for increasing the incident power onto the sample. Consequently, we achieved enhancement in signal intensity and the signal-to-noise ratio by factors of 39 and 5, respectively, compared to FT-CARS spectroscopy with homodyne detection. The sensitivity-improved rapid-scan FT-CARS spectroscopy is expected to enable the sensitive real-time observation of chemical dynamics in a broad range of settings, such as combustion engines and live biological cells.

  9. Scanning electron microscopy and X-ray spectroscopy applied to mycelial phase of sporothrix schenckii

    Directory of Open Access Journals (Sweden)

    M. Thibaut

    1975-04-01

    Full Text Available Scanning electron microscopy applied to the mycelial phase of Sporothrix schenckii shows a matted mycelium with conidia of a regular pattern. X-Ray microanalysis applied in energy dispersive spectroscopy and also in wavelength dispersive spectroscopy reveals the presence of several elements of Mendeleef's classification.

  10. Scanning deep level transient spectroscopy using an MeV ion microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Laird, J.S.; Bardos, R.A.; Saint, A.; Moloney, G.M.; Legge, G.F.J. [Melbourne Univ., Parkville, VIC (Australia)

    1993-12-31

    Traditionally the scanning ion microprobe has given little or no information regarding the electronic structure of materials in particular semiconductors. A new imaging technique called Scanning Ion Deep Level Transient Spectroscopy (SIDLTS) is presented which is able to spatially map alterations in the band gap structure of materials by lattice defects or impurities. 3 refs., 2 figs.

  11. Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Matthew W. [Iowa State Univ., Ames, IA (United States)

    2013-01-01

    This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dispersive multichannel Raman spectroscopy to 1064 nm reduces the fluorescence interference that can mask the weaker Raman scattering. Overall, these techniques help address the major obstacles in Raman spectroscopy for chemical analysis, which include the inherently weak Raman cross section and susceptibility to fluorescence interference.

  12. Solid state physics: advanced spectroscopy, scanning probe microscopy, nanostructure fabrication

    CERN Document Server

    Aghion, Stefano

    Thin films of hybrid solar cells and metal oxide semiconductors -IGZO in particular– and homogeneous PMMA polymers have been studied at the Positron Laboratory (L-NESS centre, Politecnico di Milano, Polo Territoriale di Como). A slow energy positron beam and a positron lifetime spectrometer have been employed for these studies. The positron spectroscopy information have been correlated with electrical and optical properties of the materials. The chemical composition and the morphology of voids and porosities in hybrid solar cells and thin film metal oxide semiconductors have been studied, and a strong correlation between positronium fraction, S-parameter and the electrical properties of these materials has been found. In PMMA polymers, free volume measurements have shown that the optical properties of the material depend on the presence of monomer residual fraction and even slight changes in the dimensions and concentration of free volumes. Positrons have been also applied to the study of positron to positr...

  13. Metallocene Molecular Clusters Studied with Scanning Tunneling Microscopy and Spectroscopy

    Science.gov (United States)

    Kwon, Jeonghoon; Ham, Ungdon; Lee, Minjun; Lim, Seong Joon; Kuk, Young

    2014-03-01

    Atomic spins and molecular magnets have been actively reported using Scanning Tunneling Microscope(STM) in recent studies. One can even assemble an artificial magnet by STM manipulation. Manganocene((C5H5)2 Mn), a sandwich complex of metallocene, is composed of one manganese atom and two cyclopentadianyl ligands. This molecule is known to reveal not only high spin number S = 5/2 at room temperature but also two structural states: monomer and molecular chain. In this presentation, we report STM images and spectroscopic results of these monomers and dimers. We try to map the molecular electronic state and the spin texture. The molecule is adsorbed on an insulating layer to decouple the spin state from the metallic substrate. We will present that manganocene can become a basic element of a spin chain.

  14. Spatially-Scanned Dual Comb Spectroscopy for Atmospheric Measurements

    Science.gov (United States)

    Cossel, K.; Waxman, E.; Giorgetta, F.; Cermak, M.; Coddington, I.; Hesselius, D.; Ruben, S.; Swann, W.; Rieker, G. B.; Newbury, N.

    2017-12-01

    Measuring trace gas emissions from sources that are spatially complex and temporally variable, such as leaking natural gas infrastructure, is challenging with current measurement systems. Here, we present a new technique that provides the path-integrated concentrations of multiple gas species between a ground station and a retroreflector mounted on a small quadcopter. Such a system could provide the ability to quantify small area emissions sources as well measure vertical mixing within the boundary layer. The system is based on a near-infrared dual frequency-comb spectroscopy system (DCS) covering 1.58-1.7 microns, which enables rapid, accurate measurements of CO2, CH4, H2O, and HDO. The eye-safe laser light is launched from a telescope on a fast azimuth, elevation gimbal to a small quadcopter carrying a lightweight retroreflector as well as a high-precision real-time kinematic GPS receiver (for real-time cm-level path length measurements) and pressure, temperature and humidity sensors. Here, we show the results of test measurements from controlled releases of CH4 as well as from test vertical profiles.

  15. Scanning tunneling spectroscopy of the surface states of Dirac fermions in thermoelectrics based on bismuth telluride

    Science.gov (United States)

    Lukyanova, L. N.; Makarenko, I. V.; Usov, O. A.; Dementev, P. A.

    2018-05-01

    The morphology of the interlayer van der Waals surface and differential tunneling conductance in p-Bi2‑xSbxTe3‑ySey solid solutions were studied by scanning tunneling microscopy and spectroscopy in dependence on compositions. The topological characteristics of the Dirac fermion surface states were determined. It was shown that the thermoelectric power factor and the material parameter enhance with the shift of the Dirac point to the top of the valence band with the increasing of atomic substitution in these thermoelectrics. A correlation between topological characteristics, power factor and material parameters was found. A growth contribution of the surface states is determined by an increase of the Fermi velocity for large atomic substitutions of Bi at x > 1.5 and small substitutions in the Te sublattice (y = 0.06). In compositions with smaller substitutions at x = (1–1.3) and y = (0.06–0.09), similar effect of the surface states is determined by raising the surface concentration of charge carriers.

  16. Perfusion lung scanning: differentiation of primary from thromboembolic pulmonary hypertension

    International Nuclear Information System (INIS)

    Lisbona, R.; Kreisman, H.; Novales-Diaz, J.; Derbekyan, V.

    1985-01-01

    Of eight patients with pulmonary arterial hypertension, final diagnosis established by autopsy or angiography, four had primary hypertension and four hypertension from thromboembolism. The perfusion lung scan was distinctly different in the two groups. The lung scan in primary pulmonary hypertension was associated with nonsegmental, patchy defects of perfusion, while in thromboembolic hypertensives it was characterized by segmental and/or lobar defects of perfusion with or without subsegmental defects. The perfusion lung scan is a valuable, noninvasive study in the evaluation of the patient with pulmonary hypertension of undetermined cause and in the exclusion of occult large-vessel pulmonary thromboembolism

  17. Comparison of thallium-201 scan and Tc-99m sestamibi scan in the differential diagnosis of breast mass

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Ihn Ho; Won, Kyu Jang; Lee, Hyung Woo; Lee, Soon Jung [College of Medicine, Yonsei Univ., Seoul (Korea, Republic of)

    1999-02-01

    We performed this study to compare Tl-201 and Tc-99m MIBI scans for the differentiation of malignant from benign breast mass. Thirty-eight female patients underwent Tl-201 breast scan and thirty-two of them also underwent Tc-99m MIBI scan of the breast. After intravenous injection of 74-111 MBq of Tl-201, early (10 minutes) and delayed (3 hours) images were obtained. Then, 555-740 MBq of Tc-99m MIBI was injected and images after 30 minutes were obtained. We compared Tl-201 and Tc-99m MIBI scans with pathologic results. Twenty-three patients were confirmed to have infiltrating duct carcinoma and fifteen patients to have benign breast mass by excisonal biopsy. The sensitivity of early and delayed Tl-201 scan and Tc-99m MIBI scan in the detection of malignant breast lesion were 100% (23/23), 82% (18/22), and 90% (18/20), respectively. The sensitivity of early Tl-201 scan was significantly higher than that of delayed Tl-201 scan, (p<0.05). The specificity of early and delayed Tl-201 scan and Tc-99m MIBI scan were 73% (11/15), 73% (11/15) and 83% (10/12), respectively (p: not significant). Three patients out of nine with fibroadenoma and one patient with atypical duct hyperplasia were false positive in both early and delayed Tl-201 scans. The size of fibroadenoma with false positive in early and delayed Tl-201 scan (4 cases) was larger than that of 11 fibroadenoma with true negative scan (p<0.01). Metastatic axillary lymph node involvement was present in fifteen patients. The sensitivity to detect metastatic nodes was 38% (5/13) for early Tl-201 images, 15% (2/13) for delayed Tl-201 images, 58% (7/12) for Tc-99m MIBI planar images and 67% (4/6) for Tc-99m MIBI SPECT. The sensitivity of Tc-99m MIBI planar or SPECT was significantly higher than that of delayed Tl-201 images (p<0.05). Early Tl-201 and Tc-99m MIBI scan are useful noninvasive methods to differentiate malignant from benign mass of breast. Tc-99m MIBI scan was sensitive in detecting axillary lymph node

  18. Comparison of thallium-201 scan and Tc-99m sestamibi scan in the differential diagnosis of breast mass

    International Nuclear Information System (INIS)

    Cho, Ihn Ho; Won, Kyu Jang; Lee, Hyung Woo; Lee, Soon Jung

    1999-01-01

    We performed this study to compare Tl-201 and Tc-99m MIBI scans for the differentiation of malignant from benign breast mass. Thirty-eight female patients underwent Tl-201 breast scan and thirty-two of them also underwent Tc-99m MIBI scan of the breast. After intravenous injection of 74-111 MBq of Tl-201, early (10 minutes) and delayed (3 hours) images were obtained. Then, 555-740 MBq of Tc-99m MIBI was injected and images after 30 minutes were obtained. We compared Tl-201 and Tc-99m MIBI scans with pathologic results. Twenty-three patients were confirmed to have infiltrating duct carcinoma and fifteen patients to have benign breast mass by excisonal biopsy. The sensitivity of early and delayed Tl-201 scan and Tc-99m MIBI scan in the detection of malignant breast lesion were 100% (23/23), 82% (18/22), and 90% (18/20), respectively. The sensitivity of early Tl-201 scan was significantly higher than that of delayed Tl-201 scan, (p<0.05). The specificity of early and delayed Tl-201 scan and Tc-99m MIBI scan were 73% (11/15), 73% (11/15) and 83% (10/12), respectively (p: not significant). Three patients out of nine with fibroadenoma and one patient with atypical duct hyperplasia were false positive in both early and delayed Tl-201 scans. The size of fibroadenoma with false positive in early and delayed Tl-201 scan (4 cases) was larger than that of 11 fibroadenoma with true negative scan (p<0.01). Metastatic axillary lymph node involvement was present in fifteen patients. The sensitivity to detect metastatic nodes was 38% (5/13) for early Tl-201 images, 15% (2/13) for delayed Tl-201 images, 58% (7/12) for Tc-99m MIBI planar images and 67% (4/6) for Tc-99m MIBI SPECT. The sensitivity of Tc-99m MIBI planar or SPECT was significantly higher than that of delayed Tl-201 images (p<0.05). Early Tl-201 and Tc-99m MIBI scan are useful noninvasive methods to differentiate malignant from benign mass of breast. Tc-99m MIBI scan was sensitive in detecting axillary lymph node

  19. The study of electrical conductivity of DNA molecules by scanning tunneling spectroscopy

    Science.gov (United States)

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

    2017-10-01

    An interest to the processes of charge transport in DNA molecules is very high, due to perspective of their using in nanoelectronics. The original sample preparation for studying electrical conductivity of DNA molecules by scanning tunneling spectroscopy has been proposed and tested. The DNA molecules immobilized on gold surface have been imaged clearly and their current-voltage curves have been measured.

  20. Scanning tunneling spectroscopy on neutron irradiated MgB2 thin films

    International Nuclear Information System (INIS)

    Di Capua, Roberto; Salluzzo, Marco; Vaglio, Ruggero; Ferdeghini, Carlo; Ferrando, Valeria; Putti, Marina; Xi Xiaoxing; Aebersold, Hans U.

    2007-01-01

    Neutron irradiation was performed on MgB 2 thin films grown by hybrid physical chemical vapor deposition. Samples irradiated with different neutron fluences, having different critical temperatures, were studied by scanning tunneling spectroscopy in order to investigate the effect of the introduced disorder on the superconducting and spectroscopic properties. A monotonic increase of the π gap with increasing disorder was found

  1. Scanning tunneling spectroscopy on neutron irradiated MgB{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Di Capua, Roberto [University of Napoli and CNR-INFM/Coherentia, Via Cinthia, Naples I-80126 (Italy)], E-mail: rdicapua@na.infn.it; Salluzzo, Marco; Vaglio, Ruggero [University of Napoli and CNR-INFM/Coherentia, Via Cinthia, Naples I-80126 (Italy); Ferdeghini, Carlo [CNR-INFM/LAMIA, Via Dodecaneso 33, Genova I-16146 (Italy); Ferrando, Valeria [CNR-INFM/LAMIA, Via Dodecaneso 33, Genova I-16146 (Italy); Pennsylvania State University, University Park, PA 16802 (United States); Putti, Marina [CNR-INFM/LAMIA, Via Dodecaneso 33, Genova I-16146 (Italy); Xi Xiaoxing [Pennsylvania State University, University Park, PA 16802 (United States); Aebersold, Hans U. [Paul Scherrer Institut, Villigen CH-5232 (Switzerland)

    2007-09-01

    Neutron irradiation was performed on MgB{sub 2} thin films grown by hybrid physical chemical vapor deposition. Samples irradiated with different neutron fluences, having different critical temperatures, were studied by scanning tunneling spectroscopy in order to investigate the effect of the introduced disorder on the superconducting and spectroscopic properties. A monotonic increase of the {pi} gap with increasing disorder was found.

  2. Scanning Ultrasonic Spectroscopy System Developed for the Inspection of Composite Flywheels

    Science.gov (United States)

    Martin, Richard E.; Baaklini, George Y.

    2002-01-01

    Composite flywheels are being considered as replacements for chemical batteries aboard the International Space Station. A flywheel stores energy in a spinning mass that can turn a generator to meet power demands. Because of the high rotational speeds of the spinning mass, extensive testing of the flywheel system must be performed prior to flight certification. With this goal in mind, a new scanning system has been developed at the NASA Glenn Research Center for the nondestructive inspection of composite flywheels and flywheel subcomponents. The system uses ultrasonic waves to excite a material and examines the response to detect and locate flaws and material variations. The ultrasonic spectroscopy system uses a transducer to send swept-frequency ultrasonic waves into a test material and then receives the returning signal with a second transducer. The received signal is then analyzed in the frequency domain using a fast Fourier transform. A second fast Fourier transform is performed to examine the spacing of the peaks in the frequency domain. The spacing of the peaks is related to the standing wave resonances that are present in the material because of the constructive and destructive interferences of the waves in the full material thickness as well as in individual layers within the material. Material variations and flaws are then identified by changes in the amplitudes and positions of the peaks in both the frequency and resonance spacing domains. This work, conducted under a grant through the Cleveland State University, extends the capabilities of an existing point-by-point ultrasonic spectroscopy system, thus allowing full-field automated inspection. Results of an ultrasonic spectroscopy scan of a plastic cylinder with intentionally seeded flaws. The result of an ultrasonic spectroscopy scan of a plastic cylinder used as a proof-of-concept specimen is shown. The cylinder contains a number of flat bottomed holes of various sizes and shapes. The scanning system

  3. Scanning gate spectroscopy of a quantum Hall island near a quantum point contact

    Science.gov (United States)

    Hackens, Benoit; Martins, Frederico; Faniel, Sebastien; Bayot, Vincent; Rosenow, Bernd; Desplanque, Ludovic; Wallart, Xavier; Pala, Marco; Sellier, Hermann; Huant, Serge

    2013-03-01

    We report on low temperature (100 mK) scanning gate experiments performed at high magnetic field (around 10 T) on a mesoscopic device patterned in an InGaAs/InAlAs heterostructure. Magnetotransport measurements yield signatures of ultra-small Quantum Hall Islands (QHI) formed by closed quantum Hall edge states and connected to propagating edge channels through tunnel barriers. Scanning gate microscopy and scanning gate spectroscopy are used to locate and probe a single QHI near a quantum point contact. The presence of Coulomb diamonds in the local spectroscopy confirms that Coulomb blockade governs transport across the QHI. Varying the microscope tip bias as well as current bias across the device, we uncover the QHI discrete energy spectrum arising from electronic confinement and we extract estimates of the gradient of the confining potential and of the edge state velocity.

  4. Fourier Transform Infrared Spectroscopy (FTIR) as a Tool for the Identification and Differentiation of Pathogenic Bacteria.

    Science.gov (United States)

    Zarnowiec, Paulina; Lechowicz, Łukasz; Czerwonka, Grzegorz; Kaca, Wiesław

    2015-01-01

    Methods of human bacterial pathogen identification need to be fast, reliable, inexpensive, and time efficient. These requirements may be met by vibrational spectroscopic techniques. The method that is most often used for bacterial detection and identification is Fourier transform infrared spectroscopy (FTIR). It enables biochemical scans of whole bacterial cells or parts thereof at infrared frequencies (4,000-600 cm(-1)). The recorded spectra must be subsequently transformed in order to minimize data variability and to amplify the chemically-based spectral differences in order to facilitate spectra interpretation and analysis. In the next step, the transformed spectra are analyzed by data reduction tools, regression techniques, and classification methods. Chemometric analysis of FTIR spectra is a basic technique for discriminating between bacteria at the genus, species, and clonal levels. Examples of bacterial pathogen identification and methods of differentiation up to the clonal level, based on infrared spectroscopy, are presented below.

  5. Using differential scanning calorimetry, laser refractometry, electrical conductivity and spectrophotometry for discrimination of different types of Bulgarian honey

    International Nuclear Information System (INIS)

    Vlaeva, I; Nikolova, K; Tsankova, D; Bodurov, I; Marudova, M; Viraneva, A; Yovcheva, T; Lekova, S

    2017-01-01

    The potential of several physical methods for investigation of the botanical origin of honey has been discussed. Samples from the three most prevalent types of honey in Bulgaria (acacia, linden and honeydew) have been used. They have been examined by laser refractometry, UV, VIS and FTIR spectroscopy, electric conductivity measurement and differential scanning calorimetry. The purpose of this study was to reveal the physical characterizations of honeys from different flora produced in Bulgaria and to identify honeys with a high apitherapy potential for future studies. (paper)

  6. Diagnostic whole body scan (pre-therapy scan) in differentiated thyroid cancer: A single center community hospital experience.

    Science.gov (United States)

    Santhanam, P; Driscoll, H K; Venkatraman, P

    2016-01-01

    Diagnostic whole body scan (pre-therapy scan) with either I-123 or I-131 (radioactive isotopes of iodine) is performed to assess the extent of thyroid cancer especially distant metastasis prior to administering the therapeutic dose of I-131. Our aim of the following study was to determine the utility of the diagnostic pre-therapy scan in the management of differentiated thyroid cancer. It was a case-control study carried out by retrospective chart review, of a randomly selected 100 patients with differentiated thyroid cancer who had followed in our community hospital over the course of 1 year. We collected data on multiple variables in the subjects - including age, gender, pre-operative size of the nodules, diagnosis, stage of the malignancy, size of the tumor, multifocality, lymphovascular invasion, dose of radioiodine used for remnant ablation, recurrence rates and persistence rates. Continuous variables were compared using the independent sample Mann-Whitney U-test whereas the Chi-square test was used for nominal variables. The mean dose of radioactive iodine administered was 97.56 (±27.98) in the pre-therapy scan group and it was 97.23 (±32.40) in the control group. There was no difference between the two groups (P - 0.45). There was also no difference in the recurrence rates between the groups (P = 1.0). There was a trend toward a higher degree of persistent cancer in the group that had the pre-therapy scans (P - 0.086). Pre-therapy scan may not affect the dose of radio-iodine I-131 used for remnant ablation of differentiated thyroid cancer and does not influence the recurrence rates. This was especially true with respect to I-131 remnant ablation for low risk tumors.

  7. Scanning electron microscopy and X-ray spectroscopy applied to mycelial phase of sporothrix schenckii

    Directory of Open Access Journals (Sweden)

    M. Thibaut

    1975-04-01

    Full Text Available Scanning electron microscopy applied to the mycelial phase of Sporothrix schenckii shows a matted mycelium with conidia of a regular pattern. X-Ray microanalysis applied in energy dispersive spectroscopy and also in wavelength dispersive spectroscopy reveals the presence of several elements of Mendeleef's classification.Sporothrix schenckii foi estudado em microscopia eletrônica. Foram observados caracteres das hífas e dos esporos, vários elementos da classificação periódica foram postos em evidência graças à micro-análise a raios X.

  8. Low Temperature Scanning Tunneling Spectroscopy of isolated Mn12-Ph Single Molecule Magnets

    Science.gov (United States)

    Reaves, K.; Han, P.; Iwaya, K.; Hitosugi, T.; Packwood, D.; Katzgraber, H. G.; Zhao, H.; Dunbar, K. R.; Kim, K.; Teizer, W.

    2015-03-01

    We study Mn12O12(C6H5COO)16(H2O)4 (Mn12-Ph) single-molecule magnets on a Cu(111) surface using scanning tunneling microscopy and scanning tunneling spectroscopy at cryogenic temperatures (T a strong bias voltage dependence within the molecular interior. The qualitative features of these I vs.V curves differ by spatial location in several intriguing ways (e.g. fixed junction impedance with increasing bias voltages). We explore these normalized I vs. V curves and present a phenomenological explanation for the observed behaviors, corresponding to the physical and electronic structure within the molecule. Funding from WPI-AIMR.

  9. Scanning tunneling spectroscopy of CdSe nanocrystals covalently bound to GaAs

    DEFF Research Database (Denmark)

    Walzer, K.; Marx, E.; Greenham, N.C.

    2003-01-01

    We present scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) measurements of CdSe nanocrystals covalently attached to doped GaAs substrates using monolayers of 1,6-hexanedithiol. STM measurements showed the formation of stable, densely packed, homogeneous monolayers...... and the bands in the substrate which are bent under the influence of the strong electric field between the closely separated semiconductor substrate and STM tip. The polarity of the forward bias direction is determined by the alignment of the CdSe electronic states with the semiconductor bands. (C) 2003...

  10. Differentiation of Chronic and Aggressive Periodontitis by FTIR Spectroscopy.

    Science.gov (United States)

    Simsek Ozek, N; Zeller, I; Renaud, D E; Gümüş, P; Nizam, N; Severcan, F; Buduneli, N; Scott, D A

    2016-12-01

    Without longitudinal clinical data, it is difficult to differentiate some cases of chronic periodontitis (CP) and aggressive periodontitis (AgP). Furthermore, both forms of disease are exacerbated by tobacco use. Therefore, this cross-sectional study was planned, primarily, to determine the ability of Fourier-transform infrared (FTIR) spectroscopy to distinguish CP and AgP patients by analysis of human saliva samples and, secondarily, to assess the potential confounding influence of smoking on discriminating disease-specific spectral signatures. FTIR spectra were collected from patients with a clinical diagnosis of CP (n = 18; 7 smokers) or AgP (n = 23; 9 smokers). Self-reported smoking status, which may be unreliable, was confirmed by salivary cotinine analysis. Spectral band area analysis and hierarchical cluster analyses were performed to clarify if the 2 periodontitis groups as well as smoker and nonsmoker patients could be differentiated from each other. Significant variations in lipid, amino acid, lactic acid, and nucleic acid content were found between nonsmoker CP and AgP groups. Although significantly lower lipid, phospholipid, protein, amino acid, lactic acid, and nucleic acid content was noted in the smoker AgP group compared with the nonsmoker AgP group, in the CP group, phospholipid, protein, amino acid, and lactic acid content was significantly lower for smokers compared with the nonsmokers. Based on these variations, nonsmoker CP and AgP patients were discriminated from each other with high sensitivity and specificity. Successful differentiation was also obtained for the smoker CP and AgP groups. Thiocyanate levels successfully differentiated smokers from nonsmokers, irrespective of periodontal status, with 100% accuracy. Differentiation of AgP and CP forms, concomitant with determination of smoking status, may allow the dental health professional to tailor treatment accordingly. © International & American Associations for Dental Research 2016.

  11. Note: Electron energy spectroscopy mapping of surface with scanning tunneling microscope.

    Science.gov (United States)

    Li, Meng; Xu, Chunkai; Zhang, Panke; Li, Zhean; Chen, Xiangjun

    2016-08-01

    We report a novel scanning probe electron energy spectrometer (SPEES) which combines a double toroidal analyzer with a scanning tunneling microscope to achieve both topography imaging and electron energy spectroscopy mapping of surface in situ. The spatial resolution of spectroscopy mapping is determined to be better than 0.7 ± 0.2 μm at a tip sample distance of 7 μm. Meanwhile, the size of the field emission electron beam spot on the surface is also measured, and is about 3.6 ± 0.8 μm in diameter. This unambiguously demonstrates that the spatial resolution of SPEES technique can be much better than the size of the incident electron beam.

  12. Radio frequency scanning tunneling spectroscopy for single-molecule spin resonance.

    Science.gov (United States)

    Müllegger, Stefan; Tebi, Stefano; Das, Amal K; Schöfberger, Wolfgang; Faschinger, Felix; Koch, Reinhold

    2014-09-26

    We probe nuclear and electron spins in a single molecule even beyond the electromagnetic dipole selection rules, at readily accessible magnetic fields (few mT) and temperatures (5 K) by resonant radio-frequency current from a scanning tunneling microscope. We achieve subnanometer spatial resolution combined with single-spin sensitivity, representing a 10 orders of magnitude improvement compared to existing magnetic resonance techniques. We demonstrate the successful resonant spectroscopy of the complete manifold of nuclear and electronic magnetic transitions of up to ΔI(z)=±3 and ΔJ(z)=±12 of single quantum spins in a single molecule. Our method of resonant radio-frequency scanning tunneling spectroscopy offers, atom-by-atom, unprecedented analytical power and spin control with an impact on diverse fields of nanoscience and nanotechnology.

  13. Tetrairon(III) Single Molecule Magnet Studied by Scanning Tunneling Microscopy and Spectroscopy

    Science.gov (United States)

    Oh, Youngtek; Jeong, Hogyun; Lee, Minjun; Kwon, Jeonghoon; Yu, Jaejun; Mamun, Shariful Islam; Gupta, Gajendra; Kim, Jinkwon; Kuk, Young

    2011-03-01

    Tetrairon(III) single-molecule magnet (SMM) on a clean Au(111) has studied using scanning tunneling microscopy (STM) and spectroscopy (STS) to understand quantum mechanical tunneling of magnetization and hysteresis of pure molecular origin. Before the STM studies, elemental analysis, proton nuclear magnetic resonance (NMR) measurement and Energy Dispersive X- ray Spectroscopy (EDS) were carried out to check the robustness of the sample. The STM image of this molecule shows a hexagonal shape, with a phenyl ring at the center and surrounding six dipivaloylmethane ligands. Two peaks are observed at 0.5 eV, 1.5 eV in the STS results, agreeing well with the first principles calculations. Spin-polarized scanning tunneling microscopy (SPSTM) measurements have been performed with a magnetic tip to get the magnetization image of the SMM. We could observe the antiferromagnetic coupling and a centered- triangular topology with six alkoxo bridges inside the molecule while applying external magnetic fields.

  14. Structural integrity of Synechocystis sp. PCC 6803 phycobilisomes evaluated by means of differential scanning calorimetry.

    Science.gov (United States)

    Petrova, Nia; Todinova, Svetla; Laczko-Dobos, Hajnalka; Zakar, Tomas; Vajravel, Sindhujaa; Taneva, Stefka; Gombos, Zoltan; Krumova, Sashka

    2018-01-10

    Phycobilisomes (PBSs) are supramolecular pigment-protein complexes that serve as light-harvesting antennae in cyanobacteria. They are built up by phycobiliproteins assembled into allophycocyanin core cylinders (ensuring the physical interaction with the photosystems) and phycocyanin rods (protruding from the cores and having light-harvesting function), the whole PBSs structure being maintained by linker proteins. PBSs play major role in light-harvesting optimization in cyanobacteria; therefore, the characterization of their structural integrity in intact cells is of great importance. The present study utilizes differential scanning calorimetry and spectroscopy techniques to explore for the first time, the thermodynamic stability of PBSs in intact Synechocystis sp. PCC 6803 cells and to probe its alteration as a result of mutations or under different growth conditions. As a first step, we characterize the thermodynamic behavior of intact and dismantled PBSs isolated from wild-type cells (having fully assembled PBSs) and from CK mutant cells (that lack phycocyanin rods and contain only allophycocyanin cores), and identified the thermal transitions of phycocyanin and allophycocyanin units in vitro. Next, we demonstrate that in intact cells PBSs exhibit sharp, high amplitude thermal transition at about 63 °C that strongly depends on the structural integrity of the PBSs supercomplex. Our findings implicate that calorimetry could offer a valuable approach for the assessment of the influence of variety of factors affecting the stability and structural organization of phycobilisomes in intact cyanobacterial cells.

  15. Scanning tunneling spectroscopy on heavy-fermion systems; Rastertunnelspektroskopie an Schwere-Fermionen-Systemen

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, Stefan

    2011-06-24

    in the framework of this thesis different heavy-fermion systems were studied by means of scanning tunneling microscopy and spectroscopy. In the experiment two main topics existed. On the one hand the heavy-fermion superconductivity in the compounds CeCu{sub 2}Si{sub 2}, CeCoIn{sub 5}, and on the other hand the Kondo effect in the Kondo-lattice system YbRh{sub 2}Si{sub 2}.

  16. Measuring and imaging diffusion with multiple scan speed image correlation spectroscopy.

    Science.gov (United States)

    Gröner, Nadine; Capoulade, Jérémie; Cremer, Christoph; Wachsmuth, Malte

    2010-09-27

    The intracellular mobility of biomolecules is determined by transport and diffusion as well as molecular interactions and is crucial for many processes in living cells. Methods of fluorescence microscopy like confocal laser scanning microscopy (CLSM) can be used to characterize the intracellular distribution of fluorescently labeled biomolecules. Fluorescence correlation spectroscopy (FCS) is used to describe diffusion, transport and photo-physical processes quantitatively. As an alternative to FCS, spatially resolved measurements of mobilities can be implemented using a CLSM by utilizing the spatio-temporal information inscribed into the image by the scan process, referred to as raster image correlation spectroscopy (RICS). Here we present and discuss an extended approach, multiple scan speed image correlation spectroscopy (msICS), which benefits from the advantages of RICS, i.e. the use of widely available instrumentation and the extraction of spatially resolved mobility information, without the need of a priori knowledge of diffusion properties. In addition, msICS covers a broad dynamic range, generates correlation data comparable to FCS measurements, and allows to derive two-dimensional maps of diffusion coefficients. We show the applicability of msICS to fluorophores in solution and to free EGFP in living cells.

  17. Differentiation and quality estimation of Cordyceps with infrared spectroscopy

    Science.gov (United States)

    Yang, Ping; Song, Ping; Sun, Su-Qin; Zhou, Qun; Feng, Shu; Tao, Jia-Xun

    2009-11-01

    Heretofore, a scientific and systemic method for differentiation and quality estimation of a well-known Chinese traditional medicine, 'Cordyceps', has not been established in modern market. In this paper, Fourier-transform infrared spectroscopy (FTIR) and two-dimensional correlation infrared spectroscopy (2D-IR) are employed to propose a method for analysis of Cordyceps. It has presented that IR spectra of real Cordyceps of different origins and counterfeits have their own macroscopic fingerprints, with discriminated shapes, positions and intensities. Their secondary derivative spectra can amplify the differences and confirm the potentially characteristic IR absorption bands 1400-1700 cm -1 to be investigated in 2D-IR. Many characteristic fingerprints are discovered in 2D-IR spectra in the range of 1400-1700 cm -1 and hetero 2D spectra of 670-780 cm -1 × 1400-1700 cm -1. The different fingerprints display different chemical constitutes. Through the three steps, different Cordyceps and their counterfeits can be discriminated effectively and their qualities distinctly display. Successful analysis of eight Cordyceps capsule products has proved the practicability of the method, which can also be applied to the quality estimation of other Chinese traditional medicines.

  18. An automatic detection software for differential reflection spectroscopy

    Science.gov (United States)

    Yuksel, Seniha Esen; Dubroca, Thierry; Hummel, Rolf E.; Gader, Paul D.

    2012-06-01

    Recent terrorist attacks have sprung a need for a large scale explosive detector. Our group has developed differential reflection spectroscopy which can detect explosive residue on surfaces such as parcel, cargo and luggage. In short, broad band ultra-violet and visible light is shone onto a material (such as a parcel) moving on a conveyor belt. Upon reflection off the surface, the light intensity is recorded with a spectrograph (spectrometer in combination with a CCD camera). This reflected light intensity is then subtracted and normalized with the next data point collected, resulting in differential reflection spectra in the 200-500 nm range. Explosives show spectral finger-prints at specific wavelengths, for example, the spectrum of 2,4,6, trinitrotoluene (TNT) shows an absorption edge at 420 nm. Additionally, we have developed an automated software which detects the characteristic features of explosives. One of the biggest challenges for the algorithm is to reach a practical limit of detection. In this study, we introduce our automatic detection software which is a combination of principal component analysis and support vector machines. Finally we present the sensitivity and selectivity response of our algorithm as a function of the amount of explosive detected on a given surface.

  19. Terthiophene on Au(111: A scanning tunneling microscopy and spectroscopy study

    Directory of Open Access Journals (Sweden)

    Berndt Koslowski

    2011-09-01

    Full Text Available Terthiophene (3T molecules adsorbed on herringbone (HB reconstructed Au(111 surfaces in the low coverage regime were investigated by means of low-temperature scanning tunneling microscopy (STM and spectroscopy (STS under ultra-high vacuum conditions. The 3T molecules adsorb preferentially in fcc regions of the HB reconstruction with their longer axis oriented perpendicular to the soliton walls of the HB and at maximum mutual separation. The latter observation points to a repulsive interaction between molecules probably due to parallel electrical dipoles formed during adsorption. Constant-separation (I-V and constant-current (z-V STS clearly reveal the highest occupied (HOMO and lowest unoccupied (LUMO molecular orbitals, which are found at −1.2 eV and +2.3 eV, respectively. The HOMO–LUMO gap corresponds to that of a free molecule, indicating a rather weak interaction between 3T and Au(111. According to conductivity maps, the HOMO and LUMO are inhomogeneously distributed over the adsorbed 3T, with the HOMO being located at the ends of the linear molecule, and the LUMO symmetrically with respect to the longer axis of the molecule at the center of its flanks. Analysis of spectroscopic data reveals details of the contrast mechanism of 3T/Au(111 in STM. For that, the Shockley-like surface state of Au(111 plays an essential role and appears shifted outwards from the surface in the presence of the molecule. As a consequence, the molecule can be imaged even at a tunneling bias within its HOMO–LUMO gap. A more quantitative analysis of this detail resolves a previous discrepancy between the fairly small apparent STM height of 3T molecules (1.4–2.0 nm, depending on tunneling bias and a corresponding larger value of 3.5 nm based on X-ray standing wave analysis. An additionally observed linear decrease of the differential tunneling barrier at positive bias when determined on top of a 3T molecule is compared to the bias independent barrier obtained on

  20. Scanning tunneling microscopy and spectroscopy on GaN and InGaN surfaces

    International Nuclear Information System (INIS)

    Krueger, David

    2009-01-01

    Optelectronic devices based on gallium nitride (GaN) and indium gallium nitride (InGaN) are in the focus of research since more than 20 years and still have great potential for optical applications. In the first part of this work non-polar surfaces of GaN are investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and scanning tunneling microscopy (STM). In SEM and AFM, the (1 anti 100)- and especially the (anti 2110)-plane are quite corrugated. For the first time, the (anti 2110)-plane of GaN is atomically resolved in STM. In the second part InGaN quantum dot layers are investigated by X-ray photoelectron spectroscopy (XPS), scanning tunneling spectroscopy (STS) and STM. The STMmeasurements show the dependency of surface morphology on growth conditions in the metalorganic vapour phase epitaxy (MOVPE). Nucleation, a new MOVPE-strategy, is based on phase separations on surfaces. It is shown that locally varying density of states and bandgaps can be detected by STS, that means bandgap histograms and 2D-bandgap-mapping. (orig.)

  1. On the Frequency Correction in Temperature-Modulated Differential Scanning Calorimetry of Glass Transition

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, J.C.; Allan, D.C.

    2012-01-01

    Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Simulations of TMDSC signals were performed for Corning EAGLE XG® glass over a wide range of modulation frequencies. Our results reveal that the frequen...... correction. The resulting glass transition temperature from the frequency corrected reversing heat flow is thereby shown to be independent of frequency.......Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Simulations of TMDSC signals were performed for Corning EAGLE XG® glass over a wide range of modulation frequencies. Our results reveal that the frequency...

  2. Laser heating of scanning probe tips for thermal near-field spectroscopy and imaging

    Directory of Open Access Journals (Sweden)

    Brian T. O’Callahan

    2017-02-01

    Full Text Available Spectroscopy and microscopy of the thermal near-field yield valuable insight into the mechanisms of resonant near-field heat transfer and Casimir and Casimir-Polder forces, as well as providing nanoscale spatial resolution for infrared vibrational spectroscopy. A heated scanning probe tip brought close to a sample surface can excite and probe the thermal near-field. Typically, tip temperature control is provided by resistive heating of the tip cantilever. However, this requires specialized tips with limited temperature range and temporal response. By focusing laser radiation onto AFM cantilevers, we achieve heating up to ∼1800 K, with millisecond thermal response time. We demonstrate application to thermal infrared near-field spectroscopy (TINS by acquiring near-field spectra of the vibrational resonances of silicon carbide, hexagonal boron nitride, and polytetrafluoroethylene. We discuss the thermal response as a function of the incident excitation laser power and model the dominant cooling contributions. Our results provide a basis for laser heating as a viable approach for TINS, nanoscale thermal transport measurements, and thermal desorption nano-spectroscopy.

  3. MgB2 energy gap determination by scanning tunnelling spectroscopy

    International Nuclear Information System (INIS)

    Heitmann, T W; Bu, S D; Kim, D M; Choi, J H; Giencke, J; Eom, C B; Regan, K A; Rogado, N; Hayward, M A; He, T; Slusky, J S; Khalifah, P; Haas, M; Cava, R J; Larbalestier, D C; Rzchowski, M S

    2004-01-01

    We report scanning tunnelling spectroscopy (STS) measurements of the gap properties of both ceramic MgB 2 and c-axis oriented epitaxial MgB 2 thin films. Both show a temperature dependent zero bias conductance peak and evidence for two superconducting gaps. We report tunnelling spectroscopy of superconductor-insulator-superconductor (S-I-S) junctions formed in two ways in addition to normal metal-insulator-superconductor (N-I-S) junctions. We find a gap δ = 2.2-2.8 meV, with spectral features and temperature dependence that are consistent between S-I-S junction types. In addition, we observe evidence of a second, larger gap, δ 7.2 meV, consistent with a proposed two-band model

  4. Scanning tunneling spectroscopy of MoS2 monolayer in presence of ethanol gas

    Science.gov (United States)

    Hosseini, Seyed Ali; Iraji zad, Azam; Berahman, Masoud; Aghakhani Mahyari, Farzaneh; Shokouh, Seyed Hossein Hosseini

    2018-04-01

    Due to high surface to volume ratio and tunable band gap, two dimensional (2D) layered materials such as MoS2, is good candidate for gas sensing applications. This research mainly focuses on variation of Density of States (DOS) of MoS2 monolayes caused by ethanol adsorption. The nanosheets are synthesized by liquid exfoliation, and then using Scanning Tunneling Spectroscopy (STS) and Density Functional Theory (DFT), local electronic characteristic such as DOS and band gap in non-vacuum condition are analyzed. The results show that ethanol adsorption enhances DOS and deform orbitals near the valence and conduction bands that increase transport of carriers on the sheet.

  5. Differential phase microscope and micro-tomography with a Foucault knife-edge scanning filter

    Science.gov (United States)

    Watanabe, N.; Hashizume, J.; Goto, M.; Yamaguchi, M.; Tsujimura, T.; Aoki, S.

    2013-10-01

    An x-ray differential phase microscope with a Foucault knife-edge scanning filter was set up at the bending magnet source BL3C, Photon Factory. A reconstructed phase profile from the differential phase image of an aluminium wire at 5.36 keV was fairly good agreement with the numerical simulation. Phase tomography of a biological specimen, such as an Artemia cyst, could be successfully demonstrated.

  6. Examination of water phase transitions in Loblolly pine and cell wall components by differential scanning calorimetry

    Science.gov (United States)

    Samuel L. Zelinka; Michael J. Lambrecht; Samuel V. Glass; Alex C. Wiedenhoeft; Daniel J. Yelle

    2012-01-01

    This paper examines phase transformations of water in wood and isolated wood cell wall components using differential scanning calorimetry with the purpose of better understanding "Type II water" or "freezable bound water" that has been reported for cellulose and other hydrophilic polymers. Solid loblolly pine (Pinus taeda...

  7. Indirect measurement of the magnetocaloric effect using a novel differential scanning calorimeter with magnetic field

    DEFF Research Database (Denmark)

    Jeppesen, Stinus; Linderoth, Søren; Pryds, Nini

    2008-01-01

    A simple and high-sensitivity differential scanning calorimeter (DSC) unit operating under magnetic field has been built for indirect determination of the magnetocaloric effect. The principle of the measuring unit in the calorimeter is based on Peltier elements as heat flow sensors. The high...

  8. Insights into glass transition and relaxation behavior using temperature-modulated differential scanning calorimetry

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, J.C.; Allan, D.C.

    Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Our simulations of TMDSC signals prove that the frequency correction of non-reversing heat flow can give a master curve within a certain range of freque...... insights about the glass structural response to thermal treatments....

  9. Low-temperature transitions in cod and tuna determined by differential scanning calorimetry

    DEFF Research Database (Denmark)

    Jensen, Kristina Nedenskov; Jørgensen, Bo; Nielsen, Jette

    2003-01-01

    Differential scanning calorimetry measurements have revealed different thermal transitions in cod and tuna samples. Transition temperatures detected Lit -11degreesC, -15degreesC and -21degreesC were highly dependent on the annealing temperature. In tuna muscle an additional transition was observed...

  10. Detection of sunflower oil in extra virgin olive oil by fast differential scanning calorimetry

    NARCIS (Netherlands)

    Wetten, I.A.; Herwaarden, A.W.; Splinter, R.; Boerrigter-Eenling, R.; Ruth, van S.M.

    2015-01-01

    Extra virgin olive oil (EVOO) is an economically valuable product, due to its high quality and premium price. Therefore it is vulnerable for adulteration by means of the addition of cheaper vegetable oils. Differential scanning calorimetry (DSC) has been suggested as a fast technique for the

  11. Investigating Freezing Point Depression and Cirrus Cloud Nucleation Mechanisms Using a Differential Scanning Calorimeter

    Science.gov (United States)

    Bodzewski, Kentaro Y.; Caylor, Ryan L.; Comstock, Ashley M.; Hadley, Austin T.; Imholt, Felisha M.; Kirwan, Kory D.; Oyama, Kira S.; Wise, Matthew E.

    2016-01-01

    A differential scanning calorimeter was used to study homogeneous nucleation of ice from micron-sized aqueous ammonium sulfate aerosol particles. It is important to understand the conditions at which these particles nucleate ice because of their connection to cirrus cloud formation. Additionally, the concept of freezing point depression, a topic…

  12. Study of phase transition in hard microcrystalline waxes and wax blends by differential scanning calorimetry

    Czech Academy of Sciences Publication Activity Database

    Kumar, S.; Agrawal, K. M.; Khan, H. U.; Sikora, Antonín

    2004-01-01

    Roč. 22, 3 & 4 (2004), s. 337-345 ISSN 1091-6466 R&D Projects: GA AV ČR KSK4050111 Institutional research plan: CEZ:AV0Z4050913 Keywords : phase transition * hard microscrystalline waxes * differential scanning calorimetry Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.312, year: 2004

  13. Spin-polarized scanning tunneling microscopy and spectroscopy study of chromium on a Cr(001) surface.

    Science.gov (United States)

    Lagoute, J; Kawahara, S L; Chacon, C; Repain, V; Girard, Y; Rousset, S

    2011-02-02

    Several tens of chromium layers were deposited at 250 °C on a Cr(001) surface and investigated by spin-polarized scanning tunneling microscopy (SP-STM), Auger electron spectroscopy (AES) and scanning tunneling spectroscopy (STS). Chromium is found to grow with a mound-like morphology resulting from the stacking of several monolayers which do not uniformly cover the whole surface of the substrate. The terminal plane consists of an irregular array of Cr islands with lateral sizes smaller than 20 × 20 nm(2). Combined AES and STS measurements reveal the presence of a significant amount of segregants prior to and after deposition. A detailed investigation of the surface shows that it consists of two types of patches. Thanks to STS measurements, the two types of area have been identified as being either chromium pure or segregant rich. SP-STM experiments have evidenced that the antiferromagnetic layer coupling remains in the chromium mounds after deposition and is not significantly affected by the presence of the segregants.

  14. A proximal retarding field analyzer for scanning probe energy loss spectroscopy

    Science.gov (United States)

    Bauer, Karl; Murphy, Shane; Palmer, Richard E.

    2017-03-01

    A compact proximal retarding field analyzer for scanning probe energy loss spectroscopy measurements is described. Using the scanning tunneling microscope (STM) tip as a field emission (FE) electron source in conjunction with this analyzer, which is placed at a glancing angle to the surface plane, FE sample current and electron reflectivity imaging may be performed simultaneously. This is demonstrated in measurements of Ag nanostructures prepared on graphite by electron-beam lithography, where a material contrast of 13% is observed, with a lateral resolution of 25 nm, between the silver and graphite in electron reflectivity images. Topological contrast mechanisms such as edge enhancement and shadowing are also observed, giving rise to additional features in the electron reflectivity images. The same instrument configuration has been used to measure electron energy loss spectra on bare graphite, where the zero loss peak, π band plasmon loss peak and secondary electron peaks are observed. Using this simple and compact analyzer an STM, with sufficient open access to the tip-sample junction, may easily be augmented to provide simultaneous elemental and topographic mapping, supplementing STM image measurements with FE sample current and electron reflectivity images, as well as electron energy loss spectroscopy measurements, in the same instrument.

  15. Note: Microelectrode-shielding tip for scanning probe electron energy spectroscopy

    Science.gov (United States)

    Huang, Wei; Li, Zhean; Xu, Chunkai; Liu, Jian; Xu, Chunye; Chen, Xiangjun

    2018-04-01

    We report a novel microelectrode-shielding tip (ME tip) for scanning probe electron energy spectroscopy (SPEES). The shielding effect of this tip is studied through comparing the detection efficiency with the normal tip by both experiment and simulation. The results show that the backscattering count rate detected by the SPEES instrument using the normal tip begins to decrease as the tip approaches to the sample surface within 21 μm, while that using the ME tip only starts to drop off within 1 μm. This indicates that the electron energy spectra can be measured with the ME tip at a much closer tip-sample distance. Furthermore, it is also demonstrated that the ME tip can be used to obtain topography of the sample surface in situ simultaneously.

  16. Perspectives of cross-sectional scanning tunneling microscopy and spectroscopy for complex oxide physics

    Science.gov (United States)

    Wang, Aaron; Chien, TeYu

    2018-03-01

    Complex oxide heterostructure interfaces have shown novel physical phenomena which do not exist in bulk materials. These heterostructures can be used in the potential applications in the next generation devices and served as the playgrounds for the fundamental physics research. The direct measurements of the interfaces with excellent spatial resolution and physical property information is rather difficult to achieve with the existing tools. Recently developed cross-sectional scanning tunneling microscopy and spectroscopy (XSTM/S) for complex oxide interfaces have proven to be capable of providing local electronic density of states (LDOS) information at the interface with spatial resolution down to nanometer scale. In this perspective, we will briefly introduce the basic idea and some recent achievements in using XSTM/S to study complex oxide interfaces. We will also discuss the future of this technique and the field of the interfacial physics.

  17. Molecular electronics of a single photosystem I reaction center: Studies with scanning tunneling microscopy and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, I.; Lee, J.W.; Warmack, R.J.; Allison, D.P.; Greenbaum, E. [Oak Ridge National Lab., TN (United States)

    1995-03-14

    Thylakoids and photosystem I (PSI) reaction centers were imaged by scanning tunneling microscopy. The thylakoids were isolated from spinach chloroplasts, and PSI reaction centers were extracted from thylakoid membranes. Because thylakoids are relatively thick nonconductors, they were sputter-coated with Pd/Au before imaging. PSI photosynthetic centers and chemically platinized PSI were investigated without sputter-coating. They were mounted on flat gold substrates that had been treated with mercaptoacetic acid to help bind the proteins. With tunneling spectroscopy, the PSI centers displayed a semiconductor-like response with a band gap of 1.8 eV. Lightly platinized (platinized for 1 hr) centers displayed diode-like conduction that resulted in dramatic contrast changes between images taken with opposite bias voltages. The electronic properties of this system were stable under long-term storage. 42 refs., 7 figs.

  18. A variable-temperature scanning tunneling microscope capable of single-molecule vibrational spectroscopy

    International Nuclear Information System (INIS)

    Stipe, B.C.; Rezaei, M.A.; Ho, W.

    1999-01-01

    The design and performance of a variable-temperature scanning tunneling microscope (STM) is presented. The microscope operates from 8 to 350 K in ultrahigh vacuum. The thermally compensated STM is suspended by springs from the cold tip of a continuous flow cryostat and is completely surrounded by two radiation shields. The design allows for in situ dosing and irradiation of the sample as well as for the exchange of samples and STM tips. With the STM feedback loop off, the drift of the tip-sample spacing is approximately 0.001 Angstrom/min at 8 K. It is demonstrated that the STM is well-suited for the study of atomic-scale chemistry over a wide temperature range, for atomic-scale manipulation, and for single-molecule inelastic electron tunneling spectroscopy (IETS). copyright 1999 American Institute of Physics

  19. Scanning ion deep level transient spectroscopy: II. Ion irradiated Au-Si Schottky junctions

    International Nuclear Information System (INIS)

    Laird, J S; Jagadish, C; Jamieson, D N; Legge, G J F

    2006-01-01

    Here we introduce a new technique called scanning ion deep level transient spectroscopy (SIDLTS) for the spatial analysis of electrically active defects in devices. In the first part of this paper, a simple theory behind SIDLTS was introduced and factors determining its sensitivity and resolution were discussed. In this paper, we demonstrate the technique on MeV boron implantation induced defects in an Au-Si Schottky junction. SIDLTS measurements are compared with capacitance DLTS measurements over the temperature range, 100-300 K. SIDLTS analyses indicate the presence of two levels, one of which was positively identified as the E c - 0.23 eV divacancy level. The high sensitivity of SIDLTS is verified and the advantages and limitations of the technique are discussed in light of non-exponential components in the charge transient response. Reasons for several undetected levels are also discussed

  20. Temperature dependence of the superconducting proximity effect quantified by scanning tunneling spectroscopy

    Directory of Open Access Journals (Sweden)

    A. Stępniak

    2015-01-01

    Full Text Available Here, we present the first systematic study on the temperature dependence of the extension of the superconducting proximity effect in a 1–2 atomic layer thin metallic film, surrounding a superconducting Pb island. Scanning tunneling microscopy/spectroscopy (STM/STS measurements reveal the spatial variation of the local density of state on the film from 0.38 up to 1.8 K. In this temperature range the superconductivity of the island is almost unaffected and shows a constant gap of a 1.20 ± 0.03 meV. Using a superconducting Nb-tip a constant value of the proximity length of 17 ± 3 nm at 0.38 and 1.8 K is found. In contrast, experiments with a normal conductive W-tip indicate an apparent decrease of the proximity length with increasing temperature. This result is ascribed to the thermal broadening of the occupation of states of the tip, and it does not reflect an intrinsic temperature dependence of the proximity length. Our tunneling spectroscopy experiments shed fresh light on the fundamental issue of the temperature dependence of the proximity effect for atomic monolayers, where the intrinsic temperature dependence of the proximity effect is comparably weak.

  1. Sericeous thyroglobulin and whole body thyroid scan in patients with differentiated thyroid cancer

    International Nuclear Information System (INIS)

    Mendoza, G.; Cano, R.; Morales, R.; Huanca, M.; Postigo, J.; Farfan, J.

    1994-01-01

    Thyroid cancer is the most frequent malignant tumor among endocrine diseases. it has an incidence of 1,87 cases per hundred thousand habitants. Thyroglobulin is an iodo glycoprotein useful in the follow-up of patients with differentiated thyroid carcinoma. Total body scan is a well established method to localize distant functioning metastases. We report the concordance of this two methods in 22 patients attending to the Nuclear Medicine Center and proceeding from the Head and Neck Department of INEN, which had undergone total thyroidectomy, received a I-131 ablative dose, performed a total body scan and determined the thyroglobulin concentration fourteen were female patients and the same number were accounted as high risk patients. We conclude for the studied population, that an excellent correlation between thyroglobulin and scans was noted and that 6,5 ng/ml will be used as a cut-off point for the thyroglobulin determination. (authors). 40 refs., 5 tabs

  2. Scanning photoelectron microscope for nanoscale three-dimensional spatial-resolved electron spectroscopy for chemical analysis.

    Science.gov (United States)

    Horiba, K; Nakamura, Y; Nagamura, N; Toyoda, S; Kumigashira, H; Oshima, M; Amemiya, K; Senba, Y; Ohashi, H

    2011-11-01

    In order to achieve nondestructive observation of the three-dimensional spatially resolved electronic structure of solids, we have developed a scanning photoelectron microscope system with the capability of depth profiling in electron spectroscopy for chemical analysis (ESCA). We call this system 3D nano-ESCA. For focusing the x-ray, a Fresnel zone plate with a diameter of 200 μm and an outermost zone width of 35 nm is used. In order to obtain the angular dependence of the photoelectron spectra for the depth-profile analysis without rotating the sample, we adopted a modified VG Scienta R3000 analyzer with an acceptance angle of 60° as a high-resolution angle-resolved electron spectrometer. The system has been installed at the University-of-Tokyo Materials Science Outstation beamline, BL07LSU, at SPring-8. From the results of the line-scan profiles of the poly-Si/high-k gate patterns, we achieved a total spatial resolution better than 70 nm. The capability of our system for pinpoint depth-profile analysis and high-resolution chemical state analysis is demonstrated. © 2011 American Institute of Physics

  3. Method for calibration-free scanned-wavelength modulation spectroscopy for gas sensing

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, Ronald K.; Jeffries, Jay B.; Sun, Kai; Sur, Ritobrata; Chao, Xing

    2018-04-10

    A method of calibration-free scanned-wavelength modulation spectroscopy (WMS) absorption sensing is provided by obtaining absorption lineshape measurements of a gas sample on a sensor using 1f-normalized WMS-2f where an injection current to an injection current-tunable diode laser (TDL) is modulated at a frequency f, where a wavelength modulation and an intensity modulation of the TDL are simultaneously generated, extracting using a numerical lock-in program and a low-pass filter appropriate band-width WMS-nf (n=1, 2, . . . ) signals, where the WMS-nf signals are harmonics of the f, determining a physical property of the gas sample according to ratios of the WMS-nf signals, determining the zero-absorption background using scanned-wavelength WMS, and determining non-absorption losses using at least two of the harmonics, where a need for a non-absorption baseline measurement is removed from measurements in environments where collision broadening has blended transition linewidths, where calibration free WMS measurements without knowledge of the transition linewidth is enabled.

  4. Role of 18F-fluorodeoxyglucose Positron Emission Tomography scan in differentiating enhancing brain tumors

    International Nuclear Information System (INIS)

    Das, Kajal; Mathuriya, Suresh N.; Mittal, Bhagwant R.; Vasistha, Rakesh K.; Singh, Paramjit

    2011-01-01

    To determine whether F-18-fluorodeoxyglucose positron emission tomography (F-18-FDG PET) can be used to differentiate among common enhancing brain tumors such as gliomas, metastatic brain tumors, and lymphoma. We evaluated 20 patients with an enhancing brain tumor on magnetic resonance imaging (MRI). FDG PET scan was done in all patients pre operatively. For PET image analysis, regions of interest were placed over the tumor (T), contralateral cortex (C), and white matter (WM). Average and maximum pixel values were determined at each site. On the basis of these measurements, average and maximum standard uptake values (SUV avg and SUV max ) were calculated, and comparisons among lesions were then made. FDG PET appears to provide additional information for differentiating common enhancing malignant brain tumors, namely lymphoma versus high grade glioma and metastatic tumor, particularly when differential diagnoses are difficult to narrow using MRI alone

  5. Scale dependency of forest functional diversity assessed using imaging spectroscopy and airborne laser scanning

    Science.gov (United States)

    Schneider, F. D.; Morsdorf, F.; Schmid, B.; Petchey, O. L.; Hueni, A.; Schimel, D.; Schaepman, M. E.

    2016-12-01

    Forest functional traits offer a mechanistic link between ecological processes and community structure and assembly rules. However, measuring functional traits of forests in a continuous and consistent way is particularly difficult due to the complexity of in-situ measurements and geo-referencing. New imaging spectroscopy measurements overcome these limitations allowing to map physiological traits on broad spatial scales. We mapped leaf chlorophyll, carotenoids and leaf water content over 900 ha of temperate mixed forest (Fig. 1a). The selected traits are functionally important because they are indicating the photosynthetic potential of trees, leaf longevity and protection, as well as tree water and drought stress. Spatially continuous measurements on the scale of individual tree crowns allowed to assess functional diversity patterns on a range of ecological extents. We used indexes of functional richness, divergence and evenness to map different aspects of diversity. Fig. 1b shows an example of physiological richness at an extent of 240 m radius. We compared physiological to morphological diversity patterns, derived based on plant area index, canopy height and foliage height diversity. Our results show that patterns of physiological and morphological diversity generally agree, independently measured by airborne imaging spectroscopy and airborne laser scanning, respectively. The occurrence of disturbance areas and mixtures of broadleaf and needle trees were the main drivers of the observed diversity patterns. Spatial patterns at varying extents and richness-area relationships indicated that environmental filtering is the predominant community assembly process. Our results demonstrate the potential for mapping physiological and morphological diversity in a temperate mixed forest between and within species on scales relevant to study community assembly and structure from space and test the corresponding measurement schemes.

  6. Diagnosis of electrocution: The application of scanning electron microscope and energy-dispersive X-ray spectroscopy in five cases.

    Science.gov (United States)

    Visonà, S D; Chen, Y; Bernardi, P; Andrello, L; Osculati, A

    2018-03-01

    Deaths from electricity, generally, do not have specific findings at the autopsy. The diagnosis is commonly based on the circumstances of the death and the morphologic findings, above all the current mark. Yet, the skin injury due to an electrocution and other kinds of thermal injuries often cannot be differentiated with certainty. Therefore, there is a great interest in finding specific markers of electrocution. The search for the metallization of the skin through Scanning Electron Microscope equipped with Energy Dispersive X-Ray Spectroscopy (EDS) probe is of special importance in order to achieve a definite diagnosis in case of suspected electrocution. We selected five cases in which the electrocution was extremely likely considering the circumstances of the death. In each case a forensic autopsy was performed. Then, the skin specimens were stained with Hematoxylin Eosin and Perls. On the other hand, the skin lesions were examined with a scanning electron microscope equipped with EDS probe in order to evaluate the morphological ultrastructural features and the presence of deposits on the surface of the skin. The typical skin injury of the electrocution (current mark) were macroscopically detected in all of the cases. The microscopic examination of the skin lesions revealed the typical spherical vacuoles in the horny layer and, in the epidermis, the elongation of the cell nuclei as well as necrosis. Perls staining was negative in 4 out 6 cases. Ultrastructural morphology revealed the evident vacuolization of the horny layer, elongation of epidermic cells, coagulation of the elastic fibers. In the specimens collected from the site of contact with the conductor of case 1 and 2, the presence of the Kα peaks of iron was detected. In the corresponding specimens taken from cases 2, 4, 5 the microanalysis showed the Kα peaks of titanium. In case 3, titanium and carbon were found. In the suspicion of electrocution, the integrated use of different tools is recommended

  7. Value of inflammation scintigraphy and bone scan in differential diagnosis of painful affections of small joints

    International Nuclear Information System (INIS)

    Warchol, O.; Dworak, E.; Koenig, B.; Koehn, H.; Dunky, A.; Mostbeck, A.

    1998-01-01

    It was the aim of this study to evaluate different markers of inflammation such as 99m-Tc-labelled human immunoglobulin G and 99m-Tc-nanocolloid with respect to their ability to detect inflammatory or degenerative affections of small joints of hand and fingers. While conventional bone scanning reveals good agreement with clinical findings it is not well suited for screening of inflammatory processes due to its poor specificity. In small joints conventional three-phase bone scan with information of perfusion, blood pool and accumulation is not suitable due to the small ROI, low count rate with high statistics. Therefore we used inflammatory markers to overcome this problem. Immunoglobulin G was true positive in case of inflammatory lesions in 69%, and false positive in case of degenerative lesions in 24%, while nanocolloid was true positive in 72% and false positive in 14%, respectively. Significant differences were found between markers of inflammation and the bone scanning agent while both inflammatory markers, immunoglobulin G and nanocolloid demonstrated significant correlation. While bone scanning tracers detect all kinds of joint affections, immunoglobulin G and nanocolloid accumulate preferentially in inflammatory joints and therefore might be useful to differentiate between inflammatory and degenerative lesions. (author)

  8. Nanostructured platform for the detection of Neisseria gonorrhoeae using electrochemical impedance spectroscopy and differential pulse voltammetry

    International Nuclear Information System (INIS)

    Singh, R.; Matharu, Z.; Srivastava, A.K.; Sood, S.; Gupta, R.K.; Malhotra, B.D.

    2012-01-01

    We report on a nanocomposite based genosensor for the detection of Neisseria gonorrhoeae, a bacterium causing the sexually transmitted disease gonorrhoea. Amino-labeled probe DNA was covalently immobilized on electrochemically prepared polyaniline and iron oxide (PANI-Fe 3 O 4 ) nanocomposite film on an indium tin oxide (ITO) electrode. Scanning electron microscopy, transmission electron microscopy, electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) techniques have been employed to characterize surface of the modified electrode. The genosensor has detection limits of 1 x 10 -15 M and 1 x 10 -17 M, respectively, using the EIS and DPV techniques. This biosensor can discriminate a complementary sequence from a single-base mismatch and from non-complementary DNA, and has been utilized for detection of DNA extracted from N. gonorrhoeae culture, and from patient samples with N. gonorrhoeae. It is found to exhibit good specificity for N. gonorrhoeae species and shows no response towards non-gonorrhoeae type of Neisseria species (NgNs) and other gram-negative bacterias (GNBs). The affinity constant for hybridization calculated using the Langmuir adsorption isotherm model is found to be 3. 39 x 10 8 M -1 . (author)

  9. Differential scanning calorimetric study of HTPB based composite propellants in presence of nano ferric oxide

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Prajakta R.; Krishnamurthy, V.N.; Joshi, Satyawati S. [Department of Chemistry, University of Pune, Pune 411007 (India)

    2006-12-15

    A comparative study of the thermal decomposition of ammonium perchlorate (AP)/hydroxy terminated polybutadiene (HTPB) based composite propellants has been carried out in presence and absence of nano iron oxide at different heating rates in a dynamic nitrogen atmosphere using differential scanning calorimetry. The pronounced effect was a lowering of the high temperature decomposition by 49 C. A higher heat release up to 40% was observed in presence of nano ferric oxide (3.5 nm). The kinetic parameters were evaluated using the Kissinger method. The increase of the rate constant in the catalyzed propellant confirmed the enhancement of the catalytic activity of ammonium perchlorate. The scanning electron micrographs of nano Fe{sub 2}O{sub 3} incorporated in HTPB revealed a well-separated characteristic necklace-like structure of {alpha}-Fe{sub 2}O{sub 3} particles at high magnification. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  10. Proximity Effect between Two Superconductors Spatially Resolved by Scanning Tunneling Spectroscopy

    Directory of Open Access Journals (Sweden)

    V. Cherkez

    2014-03-01

    Full Text Available We present a combined experimental and theoretical study of the proximity effect in an atomic-scale controlled junction between two different superconductors. Elaborated on a Si(111 surface, the junction comprises a Pb nanocrystal with an energy gap Δ_{1}=1.2  meV, connected to a crystalline atomic monolayer of lead with Δ_{2}=0.23  meV. Using in situ scanning tunneling spectroscopy, we probe the local density of states of this hybrid system both in space and in energy, at temperatures below and above the critical temperature of the superconducting monolayer. Direct and inverse proximity effects are revealed with high resolution. Our observations are precisely explained with the help of a self-consistent solution of the Usadel equations. In particular, our results demonstrate that in the vicinity of the Pb islands, the Pb monolayer locally develops a finite proximity-induced superconducting order parameter, well above its own bulk critical temperature. This leads to a giant proximity effect where the superconducting correlations penetrate inside the monolayer a distance much larger than in a nonsuperconducting metal.

  11. Practical spatial resolution of electron energy loss spectroscopy in aberration corrected scanning transmission electron microscopy.

    Science.gov (United States)

    Shah, A B; Ramasse, Q M; Wen, J G; Bhattacharya, A; Zuo, J M

    2011-08-01

    The resolution of electron energy loss spectroscopy (EELS) is limited by delocalization of inelastic electron scattering rather than probe size in an aberration corrected scanning transmission electron microscope (STEM). In this study, we present an experimental quantification of EELS spatial resolution using chemically modulated 2×(LaMnO(3))/2×(SrTiO(3)) and 2×(SrVO(3))/2×(SrTiO(3)) superlattices by measuring the full width at half maxima (FWHM) of integrated Ti M(2,3), Ti L(2,3), V L(2,3), Mn L(2,3), La N(4,5), La N(2,3) La M(4,5) and Sr L(3) edges over the superlattices. The EELS signals recorded using large collection angles are peaked at atomic columns. The FWHM of the EELS profile, obtained by curve-fitting, reveals a systematic trend with the energy loss for the Ti, V, and Mn edges. However, the experimental FWHM of the Sr and La edges deviates significantly from the observed experimental tendency. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Rigorous numerical modeling of scattering-type scanning near-field optical microscopy and spectroscopy

    Science.gov (United States)

    Chen, Xinzhong; Lo, Chiu Fan Bowen; Zheng, William; Hu, Hai; Dai, Qing; Liu, Mengkun

    2017-11-01

    Over the last decade, scattering-type scanning near-field optical microscopy and spectroscopy have been widely used in nano-photonics and material research due to their fine spatial resolution and broad spectral range. A number of simplified analytical models have been proposed to quantitatively understand the tip-scattered near-field signal. However, a rigorous interpretation of the experimental results is still lacking at this stage. Numerical modelings, on the other hand, are mostly done by simulating the local electric field slightly above the sample surface, which only qualitatively represents the near-field signal rendered by the tip-sample interaction. In this work, we performed a more comprehensive numerical simulation which is based on realistic experimental parameters and signal extraction procedures. By directly comparing to the experiments as well as other simulation efforts, our methods offer a more accurate quantitative description of the near-field signal, paving the way for future studies of complex systems at the nanoscale.

  13. Raman spectroscopy and scanning electron microscopy characterizations of fission track method datable zircon grains.

    Science.gov (United States)

    Resende, Rosana Silveira; Sáenz, Carlos Alberto Tello; Curvo, Eduardo Augusto Campos; Constantino, Carlos José Leopoldo; Aroca, Ricardo F; Nakasuga, Wagner Massayuki

    2014-01-01

    Spectroscopic and morphological studies, designed to improve our understanding of the physicochemical phenomena that occur during zircon crystallization, are presented. The zircon fission track method (ZFTM) is used routinely in various laboratories around the world; however, there are some methodological difficulties needing attention. Depending on the surface fission track density observed under an optical microscope, the zircon grain surfaces are classified as homogeneous, heterogeneous, hybrid, or anomalous. In this study, zircon grain surfaces are characterized using complementary techniques such as optical microscopy (OM), micro-Raman spectroscopy, and scanning electron microscopy (SEM), both before and after chemical etching. Our results suggest that anomalous grains have subfamilies and that etching anisotropy related to heterogeneous grains is due to different crystallographic faces within the same polished surface that cannot be observed under an optical microscope. The improved methodology was used to determine the zircon fission track ages of samples collected from the Bauru Group located in the north of Paraná Basin, Brazil. A total of 514 zircon grains were analyzed, consisting of 10% homogeneous, about 10% heterogeneous, about 20% hybrid, and 60% anomalous grains. These results show that the age distributions obtained for homogeneous, heterogeneous, and hybrid grains are both statistically and geologically compatible.

  14. Scanning tunneling microscopy and spectroscopy studies of superconducting boron-doped diamond films

    Directory of Open Access Journals (Sweden)

    Terukazu Nishizaki, Yoshihiko Takano, Masanori Nagao, Tomohiro Takenouchi, Hiroshi Kawarada and Norio Kobayashi

    2006-01-01

    Full Text Available We report on scanning tunneling microscopy/spectroscopy (STM/STS experiments on (1 1 1-oriented epitaxial films of heavily boron-doped diamond grown by using the microwave plasma-assisted chemical vapor deposition method. STM/STS measurements were performed by 3He-refrigerator based STM under ultra-high vacuum. The STM topography on the film surface shows a corrugation (with a typical size of ~1 μm and grain-like microstructures (~5–20 nm. The tunneling conductance spectra do not show large spatial dependence and superconductivity is observed independent of the surface structures. The tunneling spectra are analyzed by the Dynes function and the superconducting energy gap is estimated to be Δ=0.87 meV at T=0.47 K, corresponding to 2Δ/kBTc=3.7. The relatively large value of the broadening parameter Γ=0.38 meV is discussed in terms of the inelastic electron scattering processes.

  15. Scanning tunneling microscopy/spectroscopy of picene thin films formed on Ag(111)

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Yasuo, E-mail: yyoshida@issp.u-tokyo.ac.jp; Yokosuka, Takuya; Hasegawa, Yukio, E-mail: hasegawa@issp.u-tokyo.ac.jp [The Institute of Solid State Physics, The University of Tokyo, Kashiwa 277-8581 (Japan); Yang, Hung-Hsiang [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Huang, Hsu-Sheng; Guan, Shu-You; Su, Wei-Bin; Chang, Chia-Seng [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China); Yanagisawa, Susumu [Department of Physics and Earth Science Department, University of the Ryukyus, 1 Nishihara, Okinawa 903-0213 (Japan); Lin, Minn-Tsong [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China); Hoffmann, Germar [The Institute of Solid State Physics, The University of Tokyo, Kashiwa 277-8581 (Japan); Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2014-09-21

    Using ultrahigh-vacuum low-temperature scanning tunneling microscopy and spectroscopy combined with first principles density functional theory calculations, we have investigated structural and electronic properties of pristine and potassium (K)-deposited picene thin films formed in situ on a Ag(111) substrate. At low coverages, the molecules are uniformly distributed with the long axis aligned along the [112{sup ¯}] direction of the substrate. At higher coverages, ordered structures composed of monolayer molecules are observed, one of which is a monolayer with tilted and flat-lying molecules resembling a (11{sup ¯}0) plane of the bulk crystalline picene. Between the molecules and the substrate, the van der Waals interaction is dominant with negligible hybridization between their electronic states; a conclusion that contrasts with the chemisorption exhibited by pentacene molecules on the same substrate. We also observed a monolayer picene thin film in which all molecules were standing to form an intermolecular π stacking. Two-dimensional delocalized electronic states are found on the K-deposited π stacking structure.

  16. Backscattering spectroscopy developments for the University of Oxford Scanning External Proton Milliprobe (SEPM)

    Science.gov (United States)

    Jarjis, R. A.

    1996-09-01

    An external beam facility has recently been developed at the University of Oxford with the aim of carrying out non-sampling material characterisations on objects which are kept at atmospheric pressure using magnetically focused scanning beam of protons. This publication deals with one part of the developments, which is the application of backscattering spectroscopy in both operational diagnosis and the analysis of solids and gases. Results are reported for tests using an experimental external beam nozzle incorporating a window for extracting the proton beam from the vacuum to a helium gas flushed external chamber housing a Si(Li) detector and a semi-conductor charged-particle detector. The latter is used in the backscattering analysis of objects whilst a second charged-particle detector is also incorporated under vacuum in order to monitor backscattering signals originating from the window and the gas present in the vicinity of the analysis volume. The aim of the development is to create controlled conditions for comprehensive analysis using both PIXE and RBS. Two new backscattering techniques are reported in this publication: (a) External Beam Multi-Dimensional Analysis (EBMA) and (b) Resonant Scattering Multi-Dimensional Analysis (RSMA). In addition, we report on the findings of an initial study of using EBMA to assess gold layer application in Japanese porcelain and Islamic manuscripts, and using RSMA in investigating gas dynamics.

  17. Recent advances and potential applications of modulated differential scanning calorimetry (mDSC) in drug development

    DEFF Research Database (Denmark)

    Knopp, Matthias Manne; Löbmann, Korbinian; Elder, David P.

    2016-01-01

    Differential scanning calorimetry (DSC) is frequently the thermal analysis technique of choice within preformulation and formulation sciences because of its ability to provide detailed information about both the physical and energetic properties of a substance and/or formulation. However......, conventional DSC has shortcomings with respect to weak transitions and overlapping events, which could be solved by the use of the more sophisticated modulated DSC (mDSC). mDSC has multiple potential applications within the pharmaceutical field and the present review provides an up-to-date overview...

  18. Investigation of Kinetic Hydrate Inhibition Using a High Pressure Micro Differential Scanning Calorimeter

    DEFF Research Database (Denmark)

    Daraboina, Nagu; Malmos, Christine; von Solms, Nicolas

    2013-01-01

    Methane hydrate formation and decomposition were investigated in the presence of the kinetic inhibitor (Luvicap EG) and synergist (polyethylene oxide; PEO) using a high pressure micro-differential scanning calorimeter (HP-μDSC) with both temperature ramping and isothermal temperature programs....... These investigations were performed using small samples in four different capillary tubes in the calorimeter cell. When the isothermal method was employed, it was found that Luvicap EG significantly delays the hydrate nucleation time as compared to water. The results obtained from the ramping method demonstrated...

  19. Study and characterization of ammonium diuranate and uranium trioxide by thermogravimetry and differential scanning calorimetry

    International Nuclear Information System (INIS)

    Dantas, J.M.

    1983-01-01

    Thermogravimetry (TG), Differential Thermogravimetry (DTG) and Differential Scanning Calorimetry (DSC) were used to characterize the thermal behavior of ammonium diuranate (ADU) and uranium trioxide (UO 3 ) produced at IPEN'S Chemical Enginnering Department. Compounds characterization was done using the molar ratios among the compounds and the oxides resulting from thermal decomposition. The TG and DTG curves registered for each sample were used for the determination of the following temperatures: - temperature of water evolution (free and crystallized water); - ammonia evolution and oxidation temperature; - ocluded ammonium nitrate decomposition temperature and - oxygen release temperature. The intermediate phases and their thermal stabilities were also identified by TG and DTG and confirmed by DSC curves, DSC curves showed also the exothermic and endothermic behavior of the processes involved. Finally, the great amount of data collected in this study can be handed as a guide by the professionals responsible for the operation of ADU,UO 3 and UF 4 pilot plants. (Author) [pt

  20. Determination of Gel Content (C-C Crosslink in Polybutadiene Rubber by Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Saeed Taghvaei Ganjali

    2014-08-01

    Full Text Available Due to the gel formation in polybutadiene and some of the problems raised in rubber industry such as groove cracking in products, quantification of the gel content and identification of the microstructure of butadiene elastomer is extremely important. In this paper, the gel content in polybutadiene rubber was identified by differential scanning calorimetry. The thermal decomposition of the polybutadiene rubber was studied by thermal analysis methods in 0-650°C. The thermal decomposition, in the same temperature range, of the polymer with different gel contents under the similar conditions showed that the oxidation and decomposition of the samples occur in three steps. The thermal analysis curves showed that the cis-trans isomerization occurs by increases in the gel content at lower temperatures of a wider thermal range with rising trans isomer and decreases in cis isomer contents, respectively. Also, with the increase in the gel content there is a tendency in lowering double bond density and there is higher energy release in oxidation and decomposition regions due to the breakage in crosslink density of polymer networks. According to the values resulting from enthalpy and heat flow rate, the thermal index was obtained for samples at two maximum temperatures related to two processes of cis-trans isomerization and the cyclization reaction. The gel content (C-C crosslink in polybutadiene rubber is determined by the interconnection between the ratio of heat flow index and gel content from the differential scanning calorimetry curves.

  1. Monitoring of butter and animal fat oxidation stability by differential scanning calorimetry (DSC

    Directory of Open Access Journals (Sweden)

    Jasminka Sadadinović

    2005-07-01

    Full Text Available Oxidation of fat is one of the basic reactions which causes the depletion of butter and animal fat quality as well as other products containing them. Since the most of reaction products of fat oxidation are harmful for consumers' health, inadequate and scarce monitoring of edible fats and fat containing products quality, presents increased health risk as well as financial loss for the producers. In fat oxidation stability estimation, standard chemical methods were used (iodine number, acid number, peroxide number, anisidine number etc., which require time and chemical usage. Differential scanning calorimetry (DSC analysis presents the simple and efficient way for butter and animal fats oxidation stability estimation. Laboratory investigations were performed to monitor oxidation stability of butter and animal fat in fresh state, as well as in spent phase, used in frying process. The results obtained were compared to the results of standard chemical analysis, and they confirmed the reproducibility and applicability of differential scanning calorimetry in oxidation stability of butter and animal fats monitoring.

  2. LIQUID COAL CHARACTERISTIC ANALYSIS WITH FOURIER TRANSFORM INFRA RED (FTIR AND DIFFERENTIAL SCANNING CALORIMETER (DSC

    Directory of Open Access Journals (Sweden)

    ATUS BUKU

    2017-02-01

    Full Text Available The aim of this study is to identify the value of compounds contained in liquid coal by using Fourier Transform Infra-Red (FTIR and Differential Scanning Calorimeter (DSC. FTIR was used to analyse the components contained in liquid coal, while the DSC is done to observe the heat reaction to the environment. Based on the Fourier Transform Infra-Red (FTIR test results it is shown that the compound contained in the liquid Coal consisting of alkanes, alkenes and alkyne. These compounds are similar compounds. The alkanes, alkenes and alkynes compounds undergo complete combustion reaction with oxygen and would produce CO2 and water vapour [H2O (g]. If incomplete combustion occurs, the reaction proceeds in the form of Carbon Monoxide CO gas or solid carbon andH2O. Combustion reaction that occurs in all these three compounds also produces a number of considerable energy. And if it has higher value of Carbon then the boiling point would be higher. From the Differential Scanning Calorimetric (DSC test results obtained some of the factors that affect the reaction speed, which are the temperature, the reaction mixture composition, and pressure. Temperature has a profound influence in coal liquefaction, because if liquid coal heated with high pressure, the carbon chain would break down into smaller chains consisting of aromatic chain, hydro-aromatic, or aliphatic. This then triggers a reaction between oil formation and polymerization reactions to form solids (char.

  3. Use of laser-induced breakdown spectroscopy for the differentiation of pathogens and viruses on substrates.

    Science.gov (United States)

    Multari, Rosalie A; Cremers, David A; Bostian, Melissa L

    2012-03-01

    In this work, the use of laser-induced breakdown spectroscopy (LIBS) to differentiate live pathogens and killed viruses on substrates is investigated. Live pathogens B. anthracis Sterne strain and F. tularensis live vaccine strain were interrogated as lawn and colonies on agar; dilutions on agar; and dilutions on glass slides, and it was found possible to differentiate among all samples. UV killed hantavirusstrains were studied as dilutions on slides and it was also found possible to differentiate among strains. To the best of our knowledge, this is the first study in which LIBS has been used to differentiate virus samples. © 2012 Optical Society of America

  4. Enhancing the early differential diagnosis of plateau iris and pupillary block using a-scan ultrasonography.

    Science.gov (United States)

    Chen, Yu-Yen; Chu, Dachen; Chou, Pesus

    2015-01-01

    To distinguish the frequently misdiagnosed plateau iris eyes from pupillary block group and normal group, we compared the ocular biometrical parameters of them by A-scan ultrasongraphy. In total, we retrospectively reviewed general characteristics and ocular findings including ocular biometric measurements of 71 normal, 39 plateau iris, and 83 pupillary block eyes. The normal controls, plateau iris group and pupillary block group were significantly different in age, but not in gender. The anterior chamber depth tended to decrease and the lens thickness tended to increase from normal to plateau iris to pupillary block eyes. Compared to those of plateau iris group, the pupillary block group had significantly shallower anterior chamber depth (2.90mm vs. 2.33mm; piris and normal eyes, only axial length and lens/axial length factor were significantly different (23.16 vs. 23.54; pbiometrics of plateau iris were significantly different from those of pupillary block eyes. However, our A-scan ultrasongraphy generally found no significant biometric differences between plateau iris and normal eyes. These findings suggest that while A-scan ultrasonography might be used as a practical tool for differentiating plateau iris and papillary block eyes, a more meticulous gonioscopy and other assessments may be necessary to distinguish plateau iris from normal eyes.

  5. Spin-polarized scanning tunneling spectroscopy of self-organized nanoscale Co islands on Au(111) surfaces.

    Science.gov (United States)

    Schouteden, K; Muzychenko, D A; Van Haesendonck, C

    2008-07-01

    Magnetic monolayer and bilayer Co islands of only a few nanometer in size were grown by atomic deposition on atomically flat Au(111) films. The islands were studied in situ by scanning tunneling microscopy (STM) and spectroscopy at low temperatures. Spin-resolved tunneling spectroscopy, using an STM tip with a magnetic coating, revealed that the Co islands exhibit a net magnetization perpendicular to the substrate surface due to the presence of spin-polarized d-states. A random distribution of islands with either upward or downward pointing magnetization was observed, without any specific correlation of magnetization orientation with island size or island height.

  6. Characterization and differentiation of normal and abnormal spermatozoa via micro-Raman spectroscopy

    Science.gov (United States)

    Huang, Z. F.; Chen, X. W.; Chen, G. N.; Chen, J. H.; Wang, J.; Lin, J. Q.; Zeng, H. S.; Chen, R.

    2013-03-01

    Growth in the percentage of spermatozoa with aberrant sperm head morphologies has been correlated with a rise in male infertility. In our study, micro-Raman spectroscopy using a new substrate was utilized to characterize and differentiate the morphologically normal and abnormal human sperm cells based on their different biochemical components by showing their different specific Raman spectra. A detailed classification based on the PCA-LDA method was performed showing a diagnostic sensitivity of 76% and specificity of 91%, with 80% classification accuracy. Our results suggest that micro-Raman spectroscopy can serve as a reliable and non-invasive tool for detection and differentiation of human spermatozoa.

  7. Enhancing the early differential diagnosis of plateau iris and pupillary block using a-scan ultrasonography.

    Directory of Open Access Journals (Sweden)

    Yu-Yen Chen

    Full Text Available To distinguish the frequently misdiagnosed plateau iris eyes from pupillary block group and normal group, we compared the ocular biometrical parameters of them by A-scan ultrasongraphy.In total, we retrospectively reviewed general characteristics and ocular findings including ocular biometric measurements of 71 normal, 39 plateau iris, and 83 pupillary block eyes.The normal controls, plateau iris group and pupillary block group were significantly different in age, but not in gender. The anterior chamber depth tended to decrease and the lens thickness tended to increase from normal to plateau iris to pupillary block eyes. Compared to those of plateau iris group, the pupillary block group had significantly shallower anterior chamber depth (2.90mm vs. 2.33mm; p<0.001, thicker lens (4.77mm vs. 5.11mm; p<0.001, shorter axial length (23.16mm vs. 22.63mm; p<0.001, smaller relative lens position (2.28 vs. 2.16; p<0.001 and larger lens/axial length factor (2.06 vs. 2.26; p<0.001. However, when comparing plateau iris and normal eyes, only axial length and lens/axial length factor were significantly different (23.16 vs. 23.54; p<0.05 and 2.06 vs. 1.96; p<0.05.Measured by A-scan ultrasonography, the ocular biometrics of plateau iris were significantly different from those of pupillary block eyes. However, our A-scan ultrasongraphy generally found no significant biometric differences between plateau iris and normal eyes. These findings suggest that while A-scan ultrasonography might be used as a practical tool for differentiating plateau iris and papillary block eyes, a more meticulous gonioscopy and other assessments may be necessary to distinguish plateau iris from normal eyes.

  8. Infrared Spectroscopy of the Transiting Exoplanets HD189733b and XO-1 Using Hubble WFC3 in Spatial Scan Mode

    Science.gov (United States)

    Deming, Drake; Wilkins, A.; McCullough, P.; Madhusudhan, N.; Agol, E.; Burrows, A.; Charbonneau, D.; Clampin, M.; Desert, J.; Gilliland, R.; Knutson, H.; Mandell, A.; Ranjan, S.; Seager, S.; Showman, A.

    2012-01-01

    Infrared transmission spectroscopy of the exoplanets HD189733b and XO-1 has been previously reported by Swain et al. and Tinetti et al. based on observations using the NICMOS instrument on the Hubble Space Telescope. The robustness of those results has been questioned, because derivation of the exoplanetary spectrum required decorrelating strong instrumental systematic effects in the NICMOS data. We here discuss results from HST/WFC3 grism 1.1-1.7 micron spectroscopy of these planets during transit. WFC3 instrumental signatures are smaller in both amplitude and complexity as compared to NICMOS. Moreover, we use a new spatial scan mode to trail the stars perpendicular to the dispersion direction during WFC3 exposures, and this increases the efficiency of the observations and reduces persistence effects in the detector. We derive the 1.4-micron water absorption spectrum of these planets during transit, discuss implications for these exoplanetary atmospheres, and compare our results to the NICMOS spectroscopy.

  9. Modulated Temperature Differential Scanning Calorimetry Theoretical and Practical Applications in Polymer Characterisation

    CERN Document Server

    Reading, Mike

    2006-01-01

    MTDSC provides a step-change increase in the power of calorimetry to characterize virtually all polymer systems including curing systems, blends and semicrystalline polymers. It enables hidden transitions to be revealed, miscibility to be accurately assessed, and phases and interfaces in complex blends to be quantified. It also enables crystallinity in complex systems to be measured and provides new insights into melting behaviour. All of this is achieved by a simple modification of conventional DSC. In 1992 a new calorimetric technique was introduced that superimposed a small modulation on top of the conventional linear temperature program typically used in differential scanning calorimetry. This was combined with a method of data analysis that enabled the sample’s response to the linear component of the temperature program to be separated from its response to the periodic component. In this way, for the first time, a signal equivalent to that of conventional DSC was obtained simultaneously with a measure ...

  10. Measurement and Model Validation of Nanofluid Specific Heat Capacity with Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Harry O'Hanley

    2012-01-01

    Full Text Available Nanofluids are being considered for heat transfer applications; therefore it is important to know their thermophysical properties accurately. In this paper we focused on nanofluid specific heat capacity. Currently, there exist two models to predict a nanofluid specific heat capacity as a function of nanoparticle concentration and material. Model I is a straight volume-weighted average; Model II is based on the assumption of thermal equilibrium between the particles and the surrounding fluid. These two models give significantly different predictions for a given system. Using differential scanning calorimetry (DSC, a robust experimental methodology for measuring the heat capacity of fluids, the specific heat capacities of water-based silica, alumina, and copper oxide nanofluids were measured. Nanoparticle concentrations were varied between 5 wt% and 50 wt%. Test results were found to be in excellent agreement with Model II, while the predictions of Model I deviated very significantly from the data. Therefore, Model II is recommended for nanofluids.

  11. Measurement of Fiber Saturation Point of Wood Using Differential Scanning Calorimetry: Measurement Fundamentals and Experimental Results

    Directory of Open Access Journals (Sweden)

    asghar tarmian

    2017-02-01

    Full Text Available In this research, the measurement fundamentals of fiber saturation point (FSP using differential scanning calorimetry (DSC method were explained. This method is based on the assumption that free water is frozen but bound water remains unfrozen in low temperatures. Thus, the FSP can be calculated by measuring the enthalpy of melting of frozen wet samples. This method measures the amount of energy absorbed or released by a sample when it is heated or cooled. Results showed that the DSC method may yield a higher FSP value compared to the widely accepted value of 30%, depending on the wood species. Both thermal and chemical (acetylation modification methods reduced the FSP but in the acetylation method, there was no linear correlation between the weight gain percentage (WPG and FSP.

  12. Characterization of lipid nanoparticles by differential scanning calorimetry, X-ray and neutron scattering.

    Science.gov (United States)

    Bunjes, Heike; Unruh, Tobias

    2007-07-10

    Differential scanning calorimetry and X-ray diffraction play a prominent role in the characterization of lipid nanoparticle (LNP) dispersions. This review shortly outlines the measurement principles of these two techniques and summarizes their applications in the field of nanodispersions of solid lipids. These methods are particularly useful for the characterization of the matrix state, polymorphism and phase behavior of the nanoparticles which may be affected by, for example, the small particle size and the composition of the dispersions. The basics of small angle X-ray and neutron scattering which are also very promising methods for the characterization of LNPs are explained in some more detail. Examples for their use in the area of solid LNPs regarding the evaluation of particle size effects and the formation of superstructures in the nanoparticle dispersions are given. Some technical questions concerning the use of the different characterization techniques in the field of LNP research are also addressed.

  13. Differential Phase Contrast with a Segmented Detector in a Scanning X-ray Microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Hornberger,B.; de Jonge, M.; Feser, M.; Holl, P.; Holzner, C.; Jacobsen, C.; Legnini, D.; Paterson, D.; Rehak, P.; et al

    2008-01-01

    Scanning X-ray microprobes are unique tools for the nanoscale investigation of specimens from the life, environmental, materials and other fields of sciences. Typically they utilize absorption and fluorescence as contrast mechanisms. Phase contrast is a complementary technique that can provide strong contrast with reduced radiation dose for weakly absorbing structures in the multi-keV range. In this paper the development of a segmented charge-integrating silicon detector which provides simultaneous absorption and differential phase contrast is reported. The detector can be used together with a fluorescence detector for the simultaneous acquisition of transmission and fluorescence data. It can be used over a wide range of photon energies, photon rates and exposure times at third-generation synchrotron radiation sources, and is currently operating at two beamlines at the Advanced Photon Source. Images obtained at around 2 keV and 10 keV demonstrate the superiority of phase contrast over absorption for specimens composed of light elements.

  14. Evaluation of Thermal Stability of Ausferrite in Austempered Ductile Iron Using Differential Scanning Calorimetry

    Science.gov (United States)

    Warsinski, Karl C.

    Austempered Ductile Iron (ADI) is prone to changes in microstructure and mechanical properties when exposed to elevated service temperatures. Differential Scanning Calorimetry has been used to evaluate the stabilizing effects of copper, nickel, molybdenum, and cobalt on the ausferrite structure. Previous studies have conflated the effects of various alloy additions, and little effort has been made to systematically catalog the effects of individual elements. The focus of the current research has been to identify alloying elements that more strongly stabilize the ausferrite structure in order to improve service life of ADI at elevated temperatures. Nickel has been shown to have a moderate stabilizing effect, while copper and molybdenum cause a much sharper increase in activation energy. Cobalt has a high stabilizing effect at 0.5% addition by weight, but a further increase to 2.36% results in a slight decrease in activation energy.

  15. Interaction of vasicine with calf thymus DNA: Molecular docking, spectroscopic and differential scanning calorimetric insights

    Science.gov (United States)

    R. S., Sai Murali; R. S., Sai Siddhardha; Rajesh Babu, D.; Venketesh, S.; Basavaraju, R.; Nageswara Rao, G.

    2017-06-01

    The present study brings out the interaction between vasicine, an alkaloid and Adhatoda vasica Nees with double stranded DNA. The physico-chemical interaction between small molecules and nucleic acids is a major area of focus in screening drugs against various cancers. Molecular probing in our study using Molecular Operating Environment (MOE) has revealed interaction of vasicine with DNA double helix. Here we report the interaction of vasicine with Calf thymus DNA. We present for the first time the results obtained from UV-visible, fluorescence spectroscopic and differential scanning calorimetric techniques that suggest a moderate to strong electrostatic, hydrophobic and van der Waals interactions mediating the DNA binding properties of vasicine, leading to disruption of DNA secondary structure.

  16. New methodology developed for the differential scanning calorimetry analysis of polymeric matrixes incorporating phase change materials

    International Nuclear Information System (INIS)

    Barreneche, Camila; Solé, Aran; Miró, Laia; Martorell, Ingrid; Cabeza, Luisa F; Fernández, A Inés

    2012-01-01

    Nowadays, thermal comfort needs in buildings have led to an increase in energy consumption of the residential and service sectors. For this reason, thermal energy storage is shown as an alternative to achieve reduction of this high consumption. Phase change materials (PCM) have been studied to store energy due to their high storage capacity. A polymeric material capable of macroencapsulating PCM was developed by the authors of this paper. However, difficulties were found while measuring the thermal properties of these materials by differential scanning calorimetry (DSC). The polymeric matrix interferes in the detection of PCM properties by DSC. To remove this interfering effect, a new methodology which replaces the conventional empty crucible used as a reference in the DSC analysis by crucibles composed of the polymeric matrix was developed. Thus, a clear signal from the PCM is obtained by subtracting the new full crucible signal from the sample signal. (paper)

  17. Study of phase changing characteristics of granular composites using differential scanning calorimetry

    International Nuclear Information System (INIS)

    Rady, Mohamed

    2009-01-01

    Characterization of the phase changing behavior of granular materials is an important issue for design and optimization of latent heat thermal energy storage (LHTES) systems. In the present work, differential scanning calorimetry (DSC) has been used to study the phase changing behavior of granular composites consisting of ceramic encapsulated phase change material (EPCM) with particle diameters of 1-3 mm. The obtained DSC curves characterizing melting and solidification of the composite material are shown to be dependent upon the values of heating and cooling rates. Direct utilization of the measured DSC curves could result in an inexact representation of the sample enthalpy change. A simple procedure has been advised to obtain accurate quantitative results from the DSC measurements based on the estimation of the thermal resistance between the sample and its enclosure. Analysis of the evolution of latent heat of EPCM with temperature at different values of cooling/heating rates is presented.

  18. Resolving glass transition in Te-based phase-change materials by modulated differential scanning calorimetry

    Science.gov (United States)

    Chen, Yimin; Mu, Sen; Wang, Guoxiang; Shen, Xiang; Wang, Junqiang; Dai, Shixun; Xu, Tiefeng; Nie, Qiuhua; Wang, Rongping

    2017-10-01

    Glass transitions of Te-based phase-change materials (PCMs) were studied by modulated differential scanning calorimetry. It was found that both Ge2Sb2Te5 and GeTe are marginal glass formers with ΔT (= T x - T g) less than 2.1 °C when the heating rate is below 3 °C min-1. The fragilities of Ge2Sb2Te5 and GeTe can be estimated as 46.0 and 39.7, respectively, around the glass transition temperature, implying that a fragile-to-strong transition would be presented in such Te-based PCMs. The above results provide direct experimental evidence to support the investigation of crystallization kinetics in supercooled liquid PCMs.

  19. Investigation of Thermal Behavior for Natural Fibres Reinforced Epoxy using Thermogravimetric and Differential Scanning Calorimetric Analysis

    Directory of Open Access Journals (Sweden)

    Fauzi F.A.

    2016-01-01

    Full Text Available This paper presented the research works on the investigation of the thermal behavior of the natural fibres; i.e. pineapple leaf fibre, kenaf fibre and mengkuang fibres reinforced epoxy. The thermogravimetric analysis and differential scanning calorimetric analysis were used to measure the thermal behavior of the treated and untreated pineapple, kenaf and mengkuang fibres reinforced epoxy. The samples for both analysis were subjected to maximum temperature 600°C at the heating rate of 10°C/min. The results showed that the treated fibres show higher maximum peak temperature as compared to the untreated fibres. Additionally, the glass transition temperature showed a lower value for all treated fibre. It can be concluded that investigation of thermal properties of these natural fibres could improve the utilization of natural fibre composites in various applications i.e. sports applications.

  20. Co on Pt(111) studied by spin-polarized scanning tunneling microscopy and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Meier, F.K.

    2006-07-01

    In this thesis the electronic properties of the bare Pt(111) surface, the structural, electronic, and magnetic properties of monolayer and double-layer high Co nanostructures as well as the spin-averaged electronic structure of single Co atoms on Pt(111) were studied by low-temperature scanning tunneling microscopy (STM) and spectroscopy (STS). The experiments on the bare Pt(111) surface and on single Co atoms have been performed in an STM facility operating at temperatures of down to 0.3 K and at magnetic fields of up to 14 T under ultra-high vacuum conditions. The facility has been taken into operation within the time period of this thesis and its specifications were tested by STS measurements. These characterization measurements show a very high stability of the tunneling junction and an energy resolution of about 100 {mu}eV, which is close to the thermal limit. The investigation of the electronic structure of the bare Pt(111) surface reveals the existence of an unoccupied surface state. By a comparison of the measured dispersion to first-principles electronic structure calculations the state is assigned to an sp-derived surface band at the lower boundary of the projected bulk band gap. The surface state exhibits a strong spin-orbit coupling induced spin splitting. The close vicinity to the bulk bands leads to a strong linear contribution to the dispersion and thus to a deviant appearance in the density of states in comparison to the surface states of the (111) surfaces of noble metals. A detailed study of Co monolayer and double-layer nanostructures on the Pt(111) surface shows that both kinds of nanostructures exhibit a highly inhomogeneous electronic structure which changes at the scale of only a few Aa due to a strong stacking dependence with respect to the Pt(111) substrate. With the help of first principles calculations the different spectroscopic appearance for Co atoms within the Co monolayer is assigned to a stacking dependent hybridization of Co states

  1. Hydrogen concentration determination in pressure tube samples using differential scanning calorimetry (dsc)

    International Nuclear Information System (INIS)

    Marinescu, R.; Mincu, M.

    2015-01-01

    Zirconium alloys are widely used as a structural material in nuclear reactors. It is known that zirconium based cladding alloys absorb hydrogen as a result of service in a pressurized water reactor. Hydrogen absorbed (during operation of the reactor) in the zirconium alloy, out of which the pressure tube is made, is one of the major factors determining the life time of the pressure tube. For monitoring the hydrides, samples of the pressure tube are periodically taken and analyzed. At normal reactor operating temperature, hydrogen has limited solubility in the zirconium lattice and precipitates out of solid solution as zirconium hydride when the solid solubility is exceeded. As a consequences material characterization of Zr-2.5Nb CANDU pressure tubes is required after manufacturing but also during the operation to assess its structural integrity and to predict its behavior until the next in-service inspection. Hydrogen and deuterium concentration determination is one of the most important parameters to be evaluated during the experimental tests. Hydrogen present in zirconium alloys has a strong effect of weakening. Following the zirconium-hydrogen reaction, the resulting zirconium hydride precipitates in the mass of material. Weakening of the material, due to the presence of 10 ppm of precipitated hydrogen significantly affects some of its properties. The concentration of hydrogen in a sample can be determined by several methods, one of them being the differential scanning calorimetry (DSC). The principle of the method consists in measuring the difference between the amount of heat required to raise the temperature of a sample and a reference to a certain value. The experiments were made using a TA Instruments DSC Q2000 calorimeter. This paper contains experimental work for hydrogen concentration determination by Differential Scanning Calorimetry (DSC) method. Also, the reproducibility and accuracy of the method used at INR Pitesti are presented. (authors)

  2. LASSI - A Scanning Differential Ac Interferometer For Surface Profile And Roughness Measurement

    Science.gov (United States)

    Makosch, Guenter

    1989-03-01

    LASSI (Laser Spot Scanning Interferometer) is a highly precise and versatile surface profilometer developed for various measurement applications in surface lapping, etching and polishing processes. The principle of measurement is based on a differential interferometer in which two parallel light beams split from a He-Ne laser are scanned across a sample surface. The phase difference of the reflected beams changes proportionally with the height variation between the two spots illuminated on the surface. In using a phase-locked method to determine the phase differences height variations of a surface can be measured with manometer precision. The range of applications of an instrument built on this principle encompasses step height, roughness, slope, and profile measurement of surface microtopographies. Special versions of this tool have also been developed for in situ monitoring of etch or deposition rates in sputter-etching and wet etching processes. In this paper, the principle of measurement will be described and some theoretical aspects of the measurement technique will be discussed. The various LASSI tools and their applications are reviewed.

  3. Differential effects of anxiety and autism on social scene scanning in males with fragile X syndrome.

    Science.gov (United States)

    Crawford, Hayley; Moss, Joanna; Oliver, Chris; Riby, Deborah

    2017-09-25

    Existing literature draws links between social attention and socio-behavioural profiles in neurodevelopmental disorders. Fragile X syndrome (FXS) is associated with a known socio-behavioural phenotype of social anxiety and social communication difficulties alongside high social motivation. However, studies investigating social attention in males with FXS are scarce. Using eye tracking, this study investigates social attention and its relationship with both anxiety and autism symptomatology in males with FXS. We compared dwell times to the background, body, and face regions of naturalistic social scenes in 11 males with FXS (M age  = 26.29) and 11 typically developing (TD) children who were matched on gender and receptive language ability (M age  = 6.28). Using informant-report measures, we then investigated the relationships between social scene scanning and anxiety, and social scene scanning and social communicative impairments. Males with FXS did not differ to TD children on overall dwell time to the background, body, or face regions of the naturalistic social scenes. Whilst males with FXS displayed developmentally 'typical' social attention, increased looking at faces was associated with both heightened anxiety and fewer social communication impairments in this group. These results offer novel insights into the mechanisms associated with social attention in FXS and provide evidence to suggest that anxiety and autism symptomatology, which are both heightened in FXS, have differential effects on social attention.

  4. Correlation between serum thyroglobulin levels and whole body scans in patients with differentiated thyroid carcinoma

    International Nuclear Information System (INIS)

    Hristova, N.; Piperkova, E.; Sergieva, S.; Tsingilev, D.; Fanariotov, D.; Kirilova, B.; Dimitrova, M.

    1999-01-01

    Postoperative follow-up study of patients with differentiated thyroid carcinoma (DTC) is currently based on periodic whole body scan (WBS) and serum thyroglobulin (Tg) assessment. The correlation between Tg levels measured and WB scans of 84 DTC patients is investigated. WBS are performed on a rotation gamma camera DIACAM (Siemens) at 48 and 72 hours after per os administration of 185-222 MBq 131 I. The levels of Tg are determined by IRMA method and kits of BYK, Germany. Normal Tg values are obtained at a control group of 27 patients free of thyroid disease. Increased Tg levels are found at 2 cases (4%) of the group of 50 patients with total thyroidectomy given 131 I without any evidence of recurrences or metastases. At the third group consisting of 18 patients with total thyroidectomy, following 131 I therapy and recurrences and/or metastases, increased Tg values were obtained in 8 cases or 44.4%. Also increased Tg levels were obtained at 4 from 16 patients (25%) subjected to total thyroidectomy but with a residual thyroid tissue proved by scintigraphy. In conclusion, a combination of both methods should be applied for improving the diagnostic and therapeutic results at the postoperative control of DTC patients

  5. Differential scanning calorimetry and surface morphology studies on coated pellets using aqueous dispersions.

    Science.gov (United States)

    Nisar-ur-Rahman; K H, Yuen; Jia Woei, Wong; Khan, Nurzalina A k

    2005-04-01

    The present study was conducted to examine the physicochemical changes during passage of drug through polymeric membranes and observe the surface morphology features of the coated pellets using scanning electron microscopy (SEM). Drug solution was first sprayed around inert pellets to form drug-layered pellets that were coated with two commercial aqueous dispersions namely, Eudragit NE30 and Kollicoat SR30 using bottom-spray fluidized bed technique. Differential scanning calorimetry (DSC) confirmed that no interactions existed between drug and polymers. Small peak of drug was observed in the DSC thermograms of Eudragit NE30 coated pellets indicating that small amount of drug was still present in the polymeric membrane after dissolution. Views of SEM revealed as the coating levels of two types of aqueous dispersions were increased the surface of the pellets become more uniform and compact. Therefore, the diffusion length for dissolution medium to enter the drug layer and dissolved drug to diffuse out would be increased at higher coating levels. The polymer surface of coated pellets after 12 hours dissolution testing seemed to be shrunk and size of the pellets were also reduced indicating the depletion of reservoir layer.

  6. Applications of differential scanning calorimetry to the study of thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Cantor, S.

    1977-01-01

    Differential scanning calorimetry (DSC) is a versatile tool for investigating the behavior of materials that store energy by melting or by undergoing solid-state transitions. Heating scans measure the enthalpy that can be stored and cooling scans yield the enthalpy that may be recovered from the material. Exotherms also provide information about supercooling. The automatic and rapid thermal cycling features of the instrument system can be used to greatly accelerate thermal decomposition that may arise from the daily duty cycle of the storage medium. These chemical reactions as well as those with containment or with substances added to improve performance can be detected from changes in the thermal spectra. In this study, DSC methods were applied to sodium sulfate decahydrate, paraffin wax, urea, and phthalimide. For Na/sub 2/SO/sub 4/.10H/sub 2/O, DSC measurements showed a decrease in heat of fusion with thermal cycling and, also, considerable supercooling; with added Na/sub 2/B/sub 4/O/sub 7/.10H/sub 2/O (borax), supercooling was greatly lessened but not entirely eliminated. Paraffin wax did not supercool nor were there any indications that thermal cycling or contact with aluminum degraded its thermal performance. Urea, when thermally cycled, decreased in melting point and in heat of fusion; this compound also supercooled about 50/sup 0/ in DSC experiments. Phthalimide, C/sub 6/H/sub 4/(CO)/sub 2/NH, did not decompose when thermally cycled through its melting point, but it did exhibit marked supercooling. However, lesser supercooling of urea and phthalimide in test-tube scale experiments suggests that supercooling derived from DSC should be applied with caution. For phthalimide, the enthalpy of fusion, determined in this study, equalled 48.1 cal/g.

  7. DOAS (differential optical absorption spectroscopy) urban pollution measurements

    Science.gov (United States)

    Stevens, Robert K.; Vossler, T. L.

    1991-05-01

    During July and August of 1990, a differential optical absorption spectrometer (DOAS) made by OPSIS Inc. was used to measure gaseous air pollutants over three separate open paths in Atlanta, GA. Over path 1 (1099 m) and path 2 (1824 m), ozone (03), sulfur dioxide (SO2) nitrogen dioxide (NO2), nitrous acid (HNO2) formaldehyde (HCHO), benzene, toluene, and o-xylene were measured. Nitric oxide (NO) and ammonia (NH3) were monitored over path 3 (143 m). The data quality and data capture depended on the compound being measured and the path over which it was measured. Data quality criteria for each compound were chosen such that the average relative standard deviation would be less than 25%. Data capture ranged from 43% for o-xylene for path 1 to 95% for ozone for path 2. Benzene, toluene, and o-xylene concentrations measured over path 2, which crossed over an interstate highway, were higher than concentrations measured over path 1, implicating emissions from vehicles on the highway as a significant source of these compounds. Federal Reference Method (FRN) instruments were located near the DOAS light receivers and measurements of 03, NO2, and NO were made concurrently with the DOAS. Correlation coefficients greater than 0.85 were obtained between the DOAS and FRM's; however, there was a difference between the mean values obtained by the two methods for 03 and NO. A gas chromatograph for measuring volatile organic compounds was operated next to the FRN's. Correlation coefficients of about 0.66 were obtained between the DOAS and GC measurements of benzene and o- xylene. However, the correlation coefficient between the DOAS and GC measurements of toluene averaged only 0.15 for the two DOAS measurement paths. The lack of correlation and other factors indicate the possibility of a localized source of toluene near the GC. In general, disagreements between the two measurement methods could be caused by atmospheric inhomogeneities or interferences in the DOAS and other methods.

  8. Differential Scanning Calorimetric (DSC) Analysis of Rotary Nickel-Titanium (NiTi) Endodontic File (RNEF)

    Science.gov (United States)

    Wu, Ray Chun Tung; Chung, C. Y.

    2012-12-01

    To determine the variation of A f along the axial length of rotary nickel-titanium endodontic files (RNEF). Three commercial brands of 4% taper RNEF: GTX (#20, 25 mm, Dentsply Tulsa Dental Specialties, Tulsa, OK, USA), K3 (#25, 25 mm) and TF (Twisted File #25, 27 mm) (Sybron Kerr, Orange, CA, USA) were cut into segments at 4 mm increment from the working tip. Regional specimens were measured for differential heat-flow over thermal cycling, generally with continuous heating or cooling (5 °C/min) and 5 min hold at set temperatures (start, finish temperatures): GTX: -55, 90 °C; K3: -55, 45 °C; TF: -55, 60 °C; using differential scanning calorimeter. This experiment demonstrated regional differences in A f along the axial length of GTX and K3 files. Similar variation was not obvious in the TF samples. A contributory effect of regional difference in strain-hardening due to grinding and machining during manufacturing is proposed.

  9. Characterization and Differentiation of Kaolins from selected Czech Deposites using infrared spectroscopy and differential thermal analysis

    Czech Academy of Sciences Publication Activity Database

    Vaculíková, Lenka; Plevová, Eva; Vallová, S.; Koutník, I.

    2011-01-01

    Roč. 8, č. 1 (2011), s. 59-67 ISSN 1214-9705 R&D Projects: GA ČR GA105/08/1398; GA ČR GP105/07/P416 Institutional research plan: CEZ:AV0Z30860518 Keywords : kaolins * infrared spectroscopy * thermal analysis Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.530, year: 2011 http://www.irsm.cas.cz/abstracts/AGG/01_11/5_Vaculikova.pdf

  10. A New Approach for Heparin Standardization: Combination of Scanning UV Spectroscopy, Nuclear Magnetic Resonance and Principal Component Analysis

    Science.gov (United States)

    Lima, Marcelo A.; Rudd, Timothy R.; de Farias, Eduardo H. C.; Ebner, Lyvia F.; Gesteira, Tarsis F.; de Souza, Lauro M.; Mendes, Aline; Córdula, Carolina R.; Martins, João R. M.; Hoppensteadt, Debra; Fareed, Jawed; Sassaki, Guilherme L.; Yates, Edwin A.; Tersariol, Ivarne L. S.; Nader, Helena B.

    2011-01-01

    The year 2007 was marked by widespread adverse clinical responses to heparin use, leading to a global recall of potentially affected heparin batches in 2008. Several analytical methods have since been developed to detect impurities in heparin preparations; however, many are costly and dependent on instrumentation with only limited accessibility. A method based on a simple UV-scanning assay, combined with principal component analysis (PCA), was developed to detect impurities, such as glycosaminoglycans, other complex polysaccharides and aromatic compounds, in heparin preparations. Results were confirmed by NMR spectroscopy. This approach provides an additional, sensitive tool to determine heparin purity and safety, even when NMR spectroscopy failed, requiring only standard laboratory equipment and computing facilities. PMID:21267460

  11. Scanning tunneling spectroscopy on the chalcopyrite solar cell absorber material Cu(In,Ga)Se{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Moenig, Harry; Saez-Araoz, Rodrigo; Lux-Steiner, Martha [Freie Universitaet Berlin (Germany); Sadewasser, Sascha; Ennaoui, Ahmed; Kaufmann, Christian; Kropp, Timo; Lauermann, Iver; Muenchenberg, Tim; Schock, Hans-Werner; Streicher, Ferdinand [Hahn- Meitner-Institut Berlin (Germany)

    2007-07-01

    Cu(In,Ga)Se{sub 2}-based thin film solar cells have reached efficiencies close to 20%. Nevertheless, little is known about electronic transport and carrier recombination in this material on a microscopic scale. Especially grain boundaries in these polycrystalline materials are considered to play an important role in the performance of these solar cells. We applied scanning tunneling microscopy and spectroscopy to gain more insight in the electronic microstructure of the material. Our results point to lateral electronic inhomogeneities on the absorber surface and to an enhanced density of states at grain boundaries. The influence of charging effects is discussed.

  12. Characterization of gold nanoparticle films: Rutherford backscattering spectroscopy, scanning electron microscopy with image analysis, and atomic force microscopy

    Directory of Open Access Journals (Sweden)

    Pia C. Lansåker

    2014-10-01

    Full Text Available Gold nanoparticle films are of interest in several branches of science and technology, and accurate sample characterization is needed but technically demanding. We prepared such films by DC magnetron sputtering and recorded their mass thickness by Rutherford backscattering spectroscopy. The geometric thickness dg—from the substrate to the tops of the nanoparticles—was obtained by scanning electron microscopy (SEM combined with image analysis as well as by atomic force microscopy (AFM. The various techniques yielded an internally consistent characterization of the films. In particular, very similar results for dg were obtained by SEM with image analysis and by AFM.

  13. Techniques for characterization of particulate matter: neutron activation analysis, x-ray photoelectron spectroscopy, scanning electron microscopy

    International Nuclear Information System (INIS)

    Hulett, L.D.; Dale, J.M.; Emery, J.F.; Lyon, W.S. Jr.; Fulkerson, W.

    1975-01-01

    Three techniques for particulate matter analysis are discussed: (1) neutron activation, which is a method that samples the entire specimen, both surface and bulk; (2) electron spectroscopy for chemical analysis (ESCA), which samples particle surfaces only; and (3) scanning electron microscopy (SEM), which reveals particle size and morphology, and can be used to determine composition differences in individual particles. These three techniques can be combined to construct highly detailed characterizations of particulate matter specimens. It is shown that multielement analysis can be quickly done by neutron activation and that surface analysis and individual particle analysis obtained by ESCA and SEM, are very important supplementary information

  14. Size dependent bandgap of molecular beam epitaxy grown InN quantum dots measured by scanning tunneling spectroscopy

    International Nuclear Information System (INIS)

    Kumar, Mahesh; Roul, Basanta; Rajpalke, Mohana K.; Bhat, Thirumaleshwara N.; Krupanidhi, S. B.; Kalghatgi, A. T.

    2011-01-01

    InN quantum dots (QDs) were grown on Si (111) by epitaxial Stranski-Krastanow growth mode using plasma-assisted molecular beam epitaxy. Single-crystalline wurtzite structure of InN QDs was verified by the x-ray diffraction and transmission electron microscopy. Scanning tunneling microscopy has been used to probe the structural aspects of QDs. A surface bandgap of InN QDs was estimated from scanning tunneling spectroscopy (STS) I-V curves and found that it is strongly dependent on the size of QDs. The observed size-dependent STS bandgap energy shifts with diameter and height were theoretical explained based on an effective mass approximation with finite-depth square-well potential model.

  15. Diffusion of myelin oligodendrocyte glycoprotein in living OLN-93 cells investigated by raster-scanning image correlation spectroscopy (RICS).

    Science.gov (United States)

    Gielen, Ellen; Smisdom, Nick; De Clercq, Ben; Vandeven, Martin; Gijsbers, Rik; Debyser, Zeger; Rigo, Jean-Michel; Hofkens, Johan; Engelborghs, Yves; Ameloot, Marcel

    2008-09-01

    Many membrane proteins and lipids are partially confined in substructures ranging from tens of nanometers to micrometers in size. Evidence for heterogeneities in the membrane of oligodendrocytes, i.e. the myelin-producing cells of the central nervous system, is almost exclusively based on detergent methods. However, as application of detergents can alter the membrane phase behaviour, it is important to investigate membrane heterogeneities in living cells. Here, we report on the first investigations of the diffusion behavior of the myelin-specific protein MOG (myelin oligodendrocyte glycoprotein) in OLN-93 as studied by the recently developed RICS (raster-scanning image correlation spectroscopy) technique. We implemented RICS on a standard confocal laser-scanning microscope with one-photon excitation and analog detection. Measurements on FITC-dextran were used to evaluate the performance of the system and the data analysis procedure.

  16. Differential scanning calorimetry thermal properties and oxidative stability indices of microwave heated extra virgin olive oils.

    Science.gov (United States)

    Chiavaro, Emma; Rodriguez-Estrada, Maria Teresa; Bendini, Alessandra; Rinaldi, Massimiliano; Cerretani, Lorenzo

    2011-01-30

    The use of differential scanning calorimetry (DSC) for assessing the deterioration effect of microwave heating on vegetable oils, and on olive oils in particular, has been partially explored in literature. The aim of this work was to evaluate the potential of DSC to discriminate among microwaved extra virgin olive oils (EvOo from different olive cultivar and origin), according to changes on thermal properties (upon cooling and heating) and traditional oxidative stability indices (peroxide, p-anisidine and TOTOX values). An elevated value of lipid oxidation was reached by the most unsaturated EvOo sample (9.5% of linoleic acid) at 6 min of microwave treatment. Free acidity significantly increased (0.42%) only for the oil sample with the highest water content (874 mg kg(-1) oil) at the longest time of treatment. Crystallisation enthalpies significantly decreased and the major exothermic peak shifted towards lower temperature, leading to enlargement of the transition range in all samples due to the formation of weak and mixed crystals among triacylglycerols and lipid degradation products. On the contrary, thermal properties upon heating appeared to similarly vary among samples. The analysis of DSC thermal properties upon cooling seemed to clearly discriminate among different EvOo samples after microwaving. The relation between changes of thermal properties and oxidation parameters should be further studied using additional oxidative stability indices on a larger set of oil samples, due to the complexity of EvOo composition. 2010 Society of Chemical Industry.

  17. Morphological Investigation into Starch Bio-Nanocomposites via Synchrotron Radiation and Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Huihua Liu

    2011-01-01

    Full Text Available We studied a hydrophilic, plasticized bionanocomposite system involving sorbitol plasticizer, amylose biopolymer, and montmorillonite (MMT for the presence of competitive interactions among them at different moisture content. Synchrotron analysis via small angle X-ray scattering (SAXS and thermal analysis using differential scanning calorimetry (DSC were performed to understand crystalline growth and the distribution of crystalline domains within the samples. The SAXS diffraction patterns showed reduced interhelix spacing in the amylose network indicating strong amylose-sorbitol interactions. Depending on the sorbitol and MMT concentration, these interactions also affected the free moisture content and crystalline domains. Domains of around 95 Å and 312 Å were found in the low-moisture-content samples as compared to a single domain of 95 Å in the high-moisture-content samples. DSC measurements confirmed that the MMT increased the onset and the melting temperature of nanocomposites. Moreover, the results showed that the ternary interactions among sorbitol-amylose-MMT supported the crystalline heterogeneity through secondary nucleation.

  18. Ionic liquids: differential scanning calorimetry as a new indirect method for determination of vaporization enthalpies.

    Science.gov (United States)

    Verevkin, Sergey P; Emel'yanenko, Vladimir N; Zaitsau, Dzmitry H; Ralys, Ricardas V; Schick, Christoph

    2012-04-12

    Differential scanning calorimetry (DSC) has been used to measure enthalpies of synthesis reactions of the 1-alkyl-3-methylimidazolium bromide [C(n)mim][Br] ionic liquids from 1-methylimidazole and n-alkyl bromides (with n = 4, 5, 6, 7, and 8). The optimal experimental conditions have been elaborated. Enthalpies of formation of these ionic liquids in the liquid state have been determined using the DSC results according to the Hess Law. The ideal-gas enthalpies of formation of [C(n)mim][Br] were calculated using the methods of quantum chemistry. They were used together with the DSC results to derive indirectly the enthalpies of vaporization of the ionic liquids under study. In order to validate the indirect determination, the experimental vaporization enthalpy of [C(4)mim][Br] was measured by using a quartz crystal microbalance (QCM). The combination of reaction enthalpy measurements by DSC with modern high-level first-principles calculations opens valuable indirect thermochemical options to obtain values of vaporization enthalpies of ionic liquids.

  19. Thermogravimetric and Differential Scanning Calorimetric Behavior of Ball-Milled Nuclear Graphite

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eung Seon; Kim, Min Hwan; Kim, Yong Wan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Yi Hyun; Cho, Seung Yon [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    An examination was made to characterize the oxidation behavior of ball-milled nuclear graphite powder through a TG-DSC analysis. With the ball milling time, the BET surface area increased with the reduction of particle size, but decreased with the chemisorptions of O{sub 2} on the activated surface. The enhancement of the oxidation after the ball milling is attributed to both increases in the specific surface area and atomic scale defects in the graphite structure. In a high temperature gas-cooled reactor, nuclear graphite has been widely used as fuel elements, moderator or reflector blocks, and core support structures owing to its excellent moderating power, mechanical properties and machinability. For the same reason, it will be used in a helium cooled ceramic reflector test blanket module for the ITER. Each submodule has a seven-layer breeding zone, including three neutron multiplier layers packed with beryllium pebbles, three lithium ceramic pebbles packed tritium breeder layers, and a reflector layer packed with 1 mm diameter graphite pebbles to reduce the volume of beryllium. The abrasion of graphite structures owing to relative motion or thermal cycle during operation may produce graphite dust. It is expected that graphite dust will be more oxidative than bulk graphite, and thus the oxidation behavior of graphite dust must be examined to analyze the safety of the reactors during an air ingress accident. In this study, the thermal stability of ball-milled graphite powder was investigated using a simultaneous thermogravimeter-differential scanning calorimeter.

  20. Challenges of the Usual Graphical Methods Used to Characterize Phase Change Materials by Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Stéphane Gibout

    2018-01-01

    Full Text Available Modeling the thermal behavior of a plant or devices using Phase Change Materials (PCM requires to know their thermophysical properties. The Differential Scanning Calorimetry (DSC is a technic largely used to investigate them. However, under the pretext to experiment with small samples, some authors consider the DSC curves as directly representing the properties of the materials without realizing that this interpretation is very often incompatible with the thermodynamics laws: as an example, although a pure substance melts at a fixed temperature T F , it is proposed a melting through a temperature range higher than T F and depending on the experiments (heating rates, sample masses..., for solutions the suggested characteristic temperatures are incompatible with the phase diagram, and also a hysteresis phenomenon is invented... In this paper, we demonstrate by a model coupling thermodynamics and conduction heat transfers, that the DSC curves are exactly compatible with the thermodynamics of phase changes (melting at fixed temperature for pure substances, in conformity with phase diagrams for solutions.... The cases of pure substances, saline solutions, substances with impurities or solid solutions are detailed. We indicate which information can, however, be given by the curves. We also propose a more sophisticated method by inverse calculations to determine the specific enthalpy whose all the thermodynamical properties can be deduced. Finally, we give some indications to understand and use the results indicating supercooling.

  1. A modified differential scanning calorimetry for determination of cell volumetric change during the freezing process.

    Science.gov (United States)

    Luo, Dawei; Han, Xu; He, Liqun; Cui, Xiangdong; Cheng, Shuxia; Lu, Caicheng; Liu, Jianghan; Gao, Dayong

    2002-01-01

    A modified analytical and experimental method using differential scanning calorimeter (DSC) was developed to determine the cell volume change during the freezing process. Two cell types were used in the study: human platelets and erythrocytes (red blood cells). Isotonic cell suspensions with different cytocrits were prepared and used in the DSC experiments. Low cooling rates were used to avoid intracellular ice formation. Cell suspensions were cooled from room temperature to -40 degrees C. Latent heat release from the freezing of cell suspensions was shown to be a linear function of cytocrit. From slope and intercept of the linear function, cell volume change was determined based on a developed theoretical model. From experimental data and theoretical analyses, it was revealed that (a) the final volume of a human platelet at -40 degrees C was 33.7% of its isotonic volume, and 15.2% of the original (at isotonic condition) intracellular water remained unfrozen inside platelets, and (b) the final volume of human erythrocyte at -40 degrees C was 50.0% of its isotonic volume, and 30.3% of the original intracellular water was kept inside cells as residual unfrozen water.

  2. Indirect measurement of the magnetocaloric effect using a novel differential scanning calorimeter with magnetic field.

    Science.gov (United States)

    Jeppesen, S; Linderoth, S; Pryds, N; Kuhn, L Theil; Jensen, J Buch

    2008-08-01

    A simple and high-sensitivity differential scanning calorimeter (DSC) unit operating under magnetic field has been built for indirect determination of the magnetocaloric effect. The principle of the measuring unit in the calorimeter is based on Peltier elements as heat flow sensors. The high sensitivity of the apparatus combined with a suitable calibration procedure allows very fast and accurate heat capacity measurements under magnetic field to be made. The device was validated from heat capacity measurements for the typical DSC reference material gallium (Ga) and a La(0.67)Ca(0.33)MnO(3) manganite system and the results were highly consistent with previous reported data for these materials. The DSC has a working range from 200 to 340 K and has been tested in magnetic fields reaching 1.8 T. The signal-to-noise ratio is in the range of 10(2)-10(3) for the described experiments. Finally the results have been compared to results from a Quantum Design(R) physical properties measuring system. The configuration of the system also has the advantage of being able to operate with other types of magnets, e.g., permanent magnets or superconducting coils, as well as the ability to be expanded to a wider temperature range.

  3. Application of differential scanning calorimetry to estimate quality and nutritional properties of food products.

    Science.gov (United States)

    Parniakov, Oleksii; Bals, Olivier; Barba, Francisco J; Mykhailyk, Viacheslav; Lebovka, Nikolai; Vorobiev, Eugene

    2018-02-11

    Over the past years, both food researchers and food industry have shown an increased interest in finding techniques that can estimate modifications in quality, nutritional, and thermophysical properties of food products during processing and/or storage. For instance, differential scanning calorimetry (DSC) has attracted the interest of scientific community because only a small amount of sample is needed for analysis. Moreover, it does not require any specific sample preparation, and is a repeatable and reliable method. In addition, DSC methodology needs a short time for experiments compared with other techniques used for the same purpose. At this stage of investigation, there is a need to evaluate the commonly accepted and new emerging DSC applications to establish the optimum conditions of emerging processing. This paper reviews the current and new insights of DSC technique for the estimation of quality, nutritional, and thermophysical properties of food products during conventional and emerging processing and/or subsequent storage. The estimation of different properties in several food matrices after processing and/or storage is also discussed.

  4. Race Differentiation Based on Raman Spectroscopy of Semen Traces for Forensic Purposes.

    Science.gov (United States)

    Muro, Claire K; Lednev, Igor K

    2017-04-18

    Several novel methods to determine externally visible characteristics of body fluid donors have been developed in recent years. These tests can help forensic investigators make predictions about the appearance of a suspect or victim, such as their sex, race, hair color, or age. While their potential benefit is undeniable, these methods destroy the physical evidence in the process. Raman spectroscopy has recently been used as a nondestructive technique to test for many of these characteristics. Here, we present the results from a study to determine the race of semen donors. Using Raman spectroscopy and multivariate data analysis, we were able to build a statistical model that accurately identified the race of all 18 semen donors in the calibration data set, as well as seven additional external validation donors. These results demonstrate Raman spectroscopy's potential to differentiate Caucasian and Black semen donors using chemometrics.

  5. Spectroscopy of surface adsorbed molecules (scanning tunneling microscopy). Progress report, May 1, 1985-April 30, 1986

    International Nuclear Information System (INIS)

    Coleman, R.V.

    1986-01-01

    A review of the scanning tunneling microscopy program is given. This article contains a description of the design and fabrication of the microscope in addition to description of studies which use the microscope: studies of charge-density waves and studies of tunnel junctions doped with metals and semiconductors. 48 refs., 26 figs

  6. SO2 EMISSION MEASUREMENT BY DOAS (DIFFERENTIAL OPTICAL ABSORPTION SPECTROSCOPY AND COSPEC (CORRELATION SPECTROSCOPY AT MERAPI VOLCANO (INDONESIA

    Directory of Open Access Journals (Sweden)

    Hanik Humaida

    2010-06-01

    Full Text Available The SO2 is one of the volcanic gases that can use as indicator of volcano activity. Commonly, SO2 emission is measured by COSPEC (Correlation Spectroscopy. This equipment has several disadvantages; such as heavy, big in size, difficulty in finding spare part, and expensive. DOAS (Differential Optical Absorption Spectroscopy is a new method for SO2 emission measurement that has advantages compares to the COSPEC. Recently, this method has been developed. The SO2 gas emission measurement of Gunung Merapi by DOAS has been carried out at Kaliadem, and also by COSPEC method as comparation. The differences of the measurement result of both methods are not significant. However, the differences of minimum and maximum result of DOAS method are smaller than that of the COSPEC. It has range between 51 ton/day and 87 ton/day for DOAS and 87 ton/day and 201 ton/day for COSPEC. The measurement of SO2 gas emission evaluated with the seismicity data especially the rockfall showed the presence of the positive correlation. It may cause the gas pressure in the subsurface influencing instability of 2006 eruption lava.   Keywords: SO2 gas, Merapi, DOAS, COSPEC

  7. Structural, Morphological, Differential Scanning Calorimetric and Thermogravimetric Studies of Ball Milled Fe Doped Nanoscale La0.67Sr0.33MnO3 Manganite

    Science.gov (United States)

    Astik, Nidhi; Jha, Prafulla K.; Pratap, Arun

    2018-03-01

    The ball milling route has been used to produce the La0.67Sr0.33Mn0.85Fe0.15O3 (LSMFO) nanocrystalline sample from oxide precursors. The sample was characterized using x-ray diffraction (XRD), a scanning electron microscope (SEM), energy dispersive x-ray spectroscopy (EDAX), differential scanning calorimetry (DSC) and thermogravimetric (TGA) measurements. The x-ray diffraction confirms the phase purity of sample and shows that the sample crystallizes in the rhombohedral perovskite structure with a R-3c space group. The scanning electron micrograph shows the presence of well-faceted crystallites of LSMFO. The EDAX spectrum demonstrates the molar ratio of different elements of nanocrystalline LSMFO. Furthermore, the crystallite size using the Debye-Scherrer formula and William-Hall analysis has been found as 24 nm and 29 nm, respectively. Our results support the idea that a good quality nanocrystalline LSMFO sample can be obtained using the ball milling route. We also discuss the DSC and TGA curves and analyse the results in terms of phase transition, calcination temperature and activation barrier energies.

  8. Differential scanning calorimetry study of glycerinated rabbit psoas muscle fibres in intermediate state of ATP hydrolysis

    Directory of Open Access Journals (Sweden)

    Farkas Nelli

    2007-06-01

    Full Text Available Abstract Background Thermal denaturation experiments were extended to study the thermal behaviour of the main motor proteins (actin and myosin in their native environment in striated muscle fibres. The interaction of actin with myosin in the highly organized muscle structure is affected by internal forces; therefore their altered conformation and interaction may differ from those obtained in solution. The energetics of long functioning intermediate states of ATP hydrolysis cycle was studied in muscle fibres by differential scanning calorimetry (DSC. Results SETARAM Micro DSC-II was used to monitor the thermal denaturation of the fibre system in rigor and in the presence of nucleotide and nucleotide analogues. The AM.ADP.Pi state of the ATP hydrolysis cycle has a very short lifetime therefore, we mimicked the different intermediate states with AMP.PNP and/or inorganic phosphate analogues Vi and AlF4 or BeFx. Studying glycerol-extracted muscle fibres from the rabbit psoas muscle by DSC, three characteristic thermal transitions were detected in rigor. The thermal transitions can be assigned to myosin heads, myosin rods and actin with transition temperatures (Tm of 52.9 ± 0.7°C, 57.9 ± 0.7°C, 63.7 ± 1.0°C. In different intermediate states of the ATP hydrolysis mimicked by nucleotide analogues a fourth thermal transition was also detected which is very likely connected with nucleotide binding domain of myosin and/or actin filaments. This transition temperature Tm4 depended on the mimicked intermediate states, and varied in the range of 66°C – 77°C. Conclusion According to DSC measurements, strongly and weakly binding states of myosin to actin were significantly different. In the presence of ADP only a moderate change of the DSC pattern was detected in comparison with rigor, whereas in ADP.Pi state trapped by Vi, AlF4 or BeFx a remarkable stabilization was detected on the myosin head and actin filament which is reflected in a 3.0 – 10.0

  9. Differentiation of mycobacterial species by FT-IR (Fourier transform infrared spectroscopy)

    International Nuclear Information System (INIS)

    Cuellar Gil, Jorge Andres; Coronado Rios, Sandra Milena; Arrubla, Roberto Carlos

    2011-01-01

    Spectroscopy Fourier transform infrared (FT-IR) was used to differentiate 10 species of mycobacteria. Mycobacterium intracellulare and M. fortuitum (ATCC). M. flavensces, M. smegmatis, M. chelone, M. gordonae, M. triviale, M. vaccae, M. terrae and M. nonchromogenicum (IP). For gender differentiation staphylococcus aureus, streptococcus viridans and streptococcus pyogenes, klebsiella pneumoniae y escherichia coli were included as controls, each species was run for triplicate in KBr and ATR. The spectra were analyzed with the method of principal components to make the first derivatives of first order (D1) in the transmission mode using KBR pellet and ATR base, and a spectral library of the first derivative of ATR was kept. The detection sensitivity was 100% with KBr and the level of differentiation was 100% in three of the four samples problems.

  10. Evaluation of peritoneal tissue by means of differential scanning calorimetry (DSC

    Directory of Open Access Journals (Sweden)

    Łukasz Pietrzyk

    2012-01-01

    Full Text Available Abdominal surgeries alter the integrity of the peritoneal layer and cause imbalances among immunological, inflammatory and angiogenic mechanisms within the tissue. During laparoscopic procedures a protective function of the peritoneal layer can be disturbed by the gas used to create a pneumoperitoneum. The aim of this study was to characterize peritoneal tissue by means of differential scanning calorimetry (DSC as a reference for future investigations on the influence of surgical procedures on the physicochemical state of the peritoneum. Thirty-seven patients participated in the study. Patients were divided into three groups according to the type of surgery: group H — patients who underwent hernia repair; group Ch — patients who underwent laparoscopic cholecystectomy; and group C — patients operated due to rectal cancer. It was observed that onset temperature (To, denaturation temperature (Tm and change of enthalpy (ΔH during thermal denaturation of peritoneal collagen in were significantly different for these three groups of patients. The mean values of onset temperature (To and denaturation temperature (Tm in group H were significantly lower, while DH in this group was significantly higher than in the two other groups (Ch and C. This preliminary study does not answer whether the differences in collagen denaturation found in peritoneal tissue from different groups of patients resulted from a different inherent state of the tissue, or from surgical procedures. However, the results suggest that DSC is an appropriate method to study subtle changes in the physicochemical condition of the peritoneum using small samples obtained during surgical procedures. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 4, pp. 700–705

  11. Differential scanning calorimetric study of antibiotic distamycin A binding with chromatin within isolated rat liver nuclei.

    Science.gov (United States)

    Prusov, Andrey N; Kolomijtseva, Galina Ya; Smirnova, Tatiana A

    2017-12-01

    Natural oligopeptide antibiotic distamycin A (Dst) biosynthesized by Streptomyces distallicus is traditionally used in medical practice as an anti-inflammatory and antitumour drug. Dst was investigated for its effect on the structural components of native chromatin directly within isolated rat liver nuclei in the presence of physiologically significant cations (magnesium or spermine and spermidine). Differential scanning calorimetry (DSC) was used to study the Dst action at molar ratio Dst/DNA = 0.1 and 0.15 mM Dst on the melting profile of nuclei suspension in different conditions. Results showed that the thermodynamic parameters of control nuclei in the presence of polyamines or Mg 2+  were different. The incubation of nuclei with Dst raised transition temperatures of relaxed (peak II) and topologically constrained DNA (peak III) by 6-8 °C and decreased by 2-4 °C that of core-histones (peak I). The total excess transition enthalpy (ΔH exc ) in buffer with polyamines (24.7 kJ/mol DNA nucleotides) increased by1.5 times versus control but in buffer with Mg 2+ , the value of ΔH exc (35.8 kJ/mol DNA nucleotides) remained unchanged. The association of Dst with chromatin in the nucleus weakens histone-DNA contacts and causes additional strengthening of interaction between two complementary DNA chains. Our results contribute towards validation of DSC to test drug ability to modulate chromatin structure in the physiological environment and to clarify the mechanism of these modulations.

  12. Intercomparative tests on phase change materials characterisation with differential scanning calorimeter

    International Nuclear Information System (INIS)

    Lazaro, Ana; Peñalosa, Conchita; Solé, Aran; Diarce, Gonzalo; Haussmann, Thomas; Fois, Magali; Zalba, Belén; Gshwander, Stefan; Cabeza, Luisa F.

    2013-01-01

    Highlights: ► Advances in intercomparative tests of enthalpy of phase change material (PCM). ► Enthalpy of PCM determined by DSC is influenced by certain factors. ► The influence factors were identified. ► A methodology to avoid these influences for heating measurements is proposed. ► Forthcoming steps are focused on calibration and cooling measurements. - Abstract: For the correct design of thermal storage systems using phase change materials (PCMs) in any application, as well as for their simulation, it is essential to characterise the materials from thermophysical and rheological standpoints (phase change enthalpy, thermal conductivity in solid and liquid phases, viscosity and density in function of temperature). Taking advantage of the different research groups facilities available in two international networks: within the IEA (International Energy Agency), the ECES Implementing Agreement (Energy Conservation through Energy Storage IA) and SHC Programme (Solar Heating and Cooling) Task 42/Annex 24 “Compact Thermal Energy Storage – Material Development for System Integration”, and the COST Action TU0802 “Next generation cost effective phase change materials for increased energy efficiency in renewable energy systems in buildings (NeCoE-PCM)” a set of Round Robin Tests (RRTs) was proposed. The objective was to come to comparable results for PCMs using Differential Scanning Calorimetry (DSC) to determine their melting enthalpy as well as their melting and solidification behaviour. The first RRT was without defining the procedure, the second one with a predefined procedure for the measurements, but not for calibration and the third one with a predefined procedure for calibration, for the measurements and also for the data evaluation. This paper presents the conclusions after the three RRT. The main conclusion of the paper is that enthalpy in function of temperature determined using a dynamic method for DSC can be influenced by certain reasons

  13. Development of a scanning microscopy by total internal reflection coupled with thermal lens spectroscopy.

    Science.gov (United States)

    Shimosaka, Takuya; Iwamoto, Kazutoshi; Izako, Masakazu; Suzuki, Asa; Uchiyama, Katsumi; Hobo, Toshiyuki

    2004-01-01

    Non-destructive measurement of a small region on a solid/liquid interface is of great importance in physical chemistry and biochemistry, especially in the research of thin films and cell membranes. Optical methods for surface analysis with high lateral resolution are suitable methods for monitoring them. We now report a new scanning optical microscopic method to which total internal reflection coupled with a thermal lens technique was introduced. Its lateral resolution was estimated both experimentally and theoretically. To experimentally estimate the resolution, the grid patterns of thin photoresist films with well-defined lateral structures were measured. The experimental resolution was about 45 microm, which was almost same as the diameter of the excitation beam at a glass/sample interface. From this result, it was verified that this new scanning microscopy ideally worked.

  14. Specific heat capacities of different clayey samples obtained by differential scanning calorimetry

    International Nuclear Information System (INIS)

    Fernandez, A.M.

    2012-01-01

    Document available in extended abstract form only. The thermo-physical properties allow to calculate heat flows and to determine the thermal behaviour of the materials. Temperature influences the rates of the physical, chemical and biological reactions and processes in the soil or a material. Variations in temperature and water content in thermal, hydraulic, mechanical and geochemical processes affect the thermal properties such as density, specific heat, thermal conductivity and thermal diffusivity. Therefore, mathematical models that describe the dependence of the thermal properties on temperature and concentration are of interest to be used in computational programs applied to the modelling of coupled thermo-mechanical-hydraulic and chemical (THMC) processes. In this work, the specific heat capacity of different clayey international reference materials was determined. Differential Scanning Calorimetry (DSC) was used for such purpose. DSC is the main tool for determining the specific heat capacities of materials as a function of temperature. The specific heat capacity, c p (J/Kg.K), is a measurement of the amount of heat required to raise the temperature of a unit mass of a substance by one unit of temperature. A change in temperature, caused by a gain or a loss of heat from a material, depends on the specific heat capacity of the material. Thus, the specific heat capacity is a key and characteristic property of a material and/or substance, which should be determine accurately. The specific heat capacity is an intensive property and, unlike the thermal conductivity and thermal diffusivity, is independent of the dry density of the material. C p of the solid samples was determined by using a SETSYS Evolution 16 thermal analyser coupled to a differential scanning calorimeter (TG-DSC-DTA) from SETARAM Instrumentation. The thermal analyser system can use a heating rate from 0.01 to 100 C/min under a dynamic argon atmosphere and temperatures ranging from ambient to

  15. Development of Near-Field Microwave Microscope with the Functionality of Scanning Tunneling Spectroscopy

    Science.gov (United States)

    Machida, Tadashi; Gaifullin, Marat B.; Ooi, Shuuich; Kato, Takuya; Sakata, Hideaki; Hirata, Kazuto

    2010-11-01

    We describe the details of an original near-field scanning microwave microscope, developed for simultaneous measurements of local density-of-states (LDOS) and local ohmic losses (LOL). Improving microwave detection systems, we have succeeded in distinguishing the LDOS and LOL even between two low resistance materials; gold and highly orientated pyrolitic graphite. The experimental data indicate that our microscope holds a capability to investigate both LDOS and LOL in nanoscale.

  16. Detecting protein complexes in living cells from laser scanning confocal image sequences by the cross correlation raster image spectroscopy method.

    Science.gov (United States)

    Digman, Michelle A; Wiseman, Paul W; Horwitz, Alan R; Gratton, Enrico

    2009-01-01

    We describe a general method for detecting molecular complexes based on the analysis of single molecule fluorescence fluctuations from laser scanning confocal images. The method detects and quantifies complexes of two different fluorescent proteins noninvasively in living cells. Because in a raster scanned image successive pixels are measured at different times, the spatial correlation of the image contains information about dynamic processes occurring over a large time range, from the microseconds to seconds. The correlation of intensity fluctuations measured simultaneously in two channels detects protein complexes that carry two molecules of different colors. This information is obtained from the entire image. A map of the spatial distribution of protein complexes in the cell and their diffusion and/or binding properties can be constructed. Using this cross correlation raster image spectroscopy method, specific locations in the cell can be visualized where dynamics of binding and unbinding of fluorescent protein complexes occur. This fluctuation imaging method can be applied to commercial laser scanning microscopes thereby making it accessible to a large community of scientists.

  17. Neuroimaging in Parkinsonism: a study with magnetic resonance and spectroscopy as tools in the differential diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcellos, Luiz Felipe Rocha [1Hospital dos Servidores do Estado, Rio de Janeiro RJ (Brazil)], e-mail: luizneurol@terra.com.br; Novis, Sergio A. Pereira; Rosso, Ana Lucia Z. [Hospital Universitario Clementino Fraga Filho (HUCFF), Rio de Janeiro, RJ (Brazil); Moreira, Denise Madeira [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Neurologia Deolindo Couto; Leite, Ana Claudia C.B. [Fundacao Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ (Brazil)

    2009-03-15

    The differential diagnosis of Parkinsonism based on clinical features, sometimes may be difficult. Diagnostic tests in these cases might be useful, especially magnetic resonance imaging, a noninvasive exam, not as expensive as positron emission tomography, and provides a good basis for anatomical analysis. The magnetic resonance spectroscopy analyzes cerebral metabolism, yielding inconsistent results in parkinsonian disorders. We selected 40 individuals for magnetic resonance imaging and spectroscopy analysis, 12 with Parkinson's disease, 11 with progressive supranuclear palsy, 7 with multiple system atrophy (parkinsonian type), and 10 individuals without any psychiatric or neurological disorders (controls). Clinical scales included Hoenh and Yahr, unified Parkinson's disease rating scale and mini mental status examination. The results showed that patients with Parkinson's disease and controls presented the same aspects on neuroimaging, with few or absence of abnormalities, and supranuclear progressive palsy and multiple system atrophy showed abnormalities, some of which statistically significant. Thus, magnetic resonance imaging and spectroscopy could be useful as a tool in differential diagnosis of Parkinsonism. (author)

  18. Neuroimaging in Parkinsonism: a study with magnetic resonance and spectroscopy as tools in the differential diagnosis

    International Nuclear Information System (INIS)

    Vasconcellos, Luiz Felipe Rocha; Novis, Sergio A. Pereira; Rosso, Ana Lucia Z.; Moreira, Denise Madeira

    2009-01-01

    The differential diagnosis of Parkinsonism based on clinical features, sometimes may be difficult. Diagnostic tests in these cases might be useful, especially magnetic resonance imaging, a noninvasive exam, not as expensive as positron emission tomography, and provides a good basis for anatomical analysis. The magnetic resonance spectroscopy analyzes cerebral metabolism, yielding inconsistent results in parkinsonian disorders. We selected 40 individuals for magnetic resonance imaging and spectroscopy analysis, 12 with Parkinson's disease, 11 with progressive supranuclear palsy, 7 with multiple system atrophy (parkinsonian type), and 10 individuals without any psychiatric or neurological disorders (controls). Clinical scales included Hoenh and Yahr, unified Parkinson's disease rating scale and mini mental status examination. The results showed that patients with Parkinson's disease and controls presented the same aspects on neuroimaging, with few or absence of abnormalities, and supranuclear progressive palsy and multiple system atrophy showed abnormalities, some of which statistically significant. Thus, magnetic resonance imaging and spectroscopy could be useful as a tool in differential diagnosis of Parkinsonism. (author)

  19. Fluorescence correlation spectroscopy, Raster image correlation spectroscopy and Number & Brightness on a commercial confocal laser scanning microscope with analog detectors (Nikon C1)

    Science.gov (United States)

    Moens, Pierre D.J.; Gratton, Enrico; Salvemini, Iyrri L.

    2010-01-01

    Fluorescence correlation spectroscopy (FCS) was developed in 1972 by Magde, Elson and Webb (Magde et al., 1972). Photon counting detectors and avalanche photodiodes have become standards in FCS to the point that there is a widespread belief that these detectors are essential to perform FCS experiments, despite the fact that FCS was developed using analog detectors. Spatial and temporal intensity fluctuation correlations using analog detection on a commercial Olympus Fluoview 300 microscope has been reported by Brown et al. (2008). However, each analog instrument has its own idiosyncrasies that need to be understood before using the instrument for FCS. In this work we explore the capabilities of the Nikon C1, a low cost confocal microscope, to obtain single point FCS, Raster-scan Image Correlation Spectroscopy (RICS) and Number & Brightness data both in solution and incorporated into the membrane of Giant Unilamellar Vesicles (GUVs). We show that it is possible to obtain dynamic information about fluorescent molecules from single point FCS, RICS and Number & Brightness using the Nikon C1. We highlighted the fact that care should be taken in selecting the acquisition parameters in order to avoid possible artifacts due to the detector noise. However, due to relatively large errors in determining the distribution of digital levels for a given microscope setting, the system is probably only adequate for determining relative brightness within the same image. PMID:20734406

  20. Fluorescence correlation spectroscopy, raster image correlation spectroscopy, and number and brightness on a commercial confocal laser scanning microscope with analog detectors (Nikon C1).

    Science.gov (United States)

    Moens, Pierre D J; Gratton, Enrico; Salvemini, Iyrri L

    2011-04-01

    Fluorescence correlation spectroscopy (FCS) was developed in 1972 by Magde, Elson and Webb. Photon counting detectors and avalanche photodiodes have become standards in FCS to the point that there is a widespread belief that these detectors are essential to perform FCS experiments, despite the fact that FCS was developed using analog detectors. Spatial and temporal intensity fluctuation correlations using analog detection on a commercial Olympus Fluoview 300 microscope have been reported by Brown et al. (2008). However, each analog instrument has its own idiosyncrasies that need to be understood before using the instrument for FCS. In this work, we explore the capabilities of the Nikon C1, a low-cost confocal microscope, to obtain single point FCS, Raster-scan image correlation spectroscopy (RICS), and Number and Brightness data both in solution and incorporated into the membrane of giant unilamellar vesicles. We show that it is possible to obtain dynamic information about fluorescent molecules from single point FCS, RICS, and Number and Brightness using the Nikon C1. We highlighted the fact that care should be taken in selecting the acquisition parameters to avoid possible artifacts due to the detector noise. However, due to relatively large errors in determining the distribution of digital levels for a given microscope setting, the system is probably only adequate for determining relative brightness within the same image. Copyright © 2010 Wiley-Liss, Inc.

  1. Empirical model description of photon path length for differential path length spectroscopy: combined effect of scattering and absorption

    NARCIS (Netherlands)

    Kanick, Stephen C.; Sterenborg, Henricus J. C. M.; Amelink, Arjen

    2008-01-01

    Differential path length spectroscopy (DPS) is a method of reflectance spectroscopy that utilizes a specialized fiber geometry to make the photon path length (tau) insensitive to variations in tissue optical properties over a wide range of absorption (mu(a)) and total scattering (mu(s))

  2. Investigations of the superconducting proximity effect in normal conducting and ferromagnetic materials using scanning tunneling spectroscopy

    International Nuclear Information System (INIS)

    Wolz, Michael

    2011-01-01

    The superconducting proximity effect (SPE) describes the mutual influence of a normal conductor and a superconductor in electrical contact. Due to the Anderson reflection at the interface the single electron based current in the normal conductor can be transformed into a dissipation free current due to Cooper pairs. Theoretical expectations on the local quasi particle density of states on layered systems with aluminum (BCS superconductor), gold and silver were compared with scanning tunneling microscopy measurements. Palladium was also studied using the proximity effect with respect to a strong electron-phonon coupling with simultaneous ferromagnetism. Another topic was the study of superconductor/ferromagnetic layer structures.

  3. Designing GABA-edited magnetic resonance spectroscopy studies: Considerations of scan duration, signal-to-noise ratio and sample size.

    Science.gov (United States)

    Mikkelsen, Mark; Loo, Rachelle S; Puts, Nicolaas A J; Edden, Richard A E; Harris, Ashley D

    2018-02-21

    The relationships between scan duration, signal-to-noise ratio (SNR) and sample size must be considered and understood to design optimal GABA-edited magnetic resonance spectroscopy (MRS) studies. Simulations investigated the effects of signal averaging on SNR, measurement error and group-level variance against a known ground truth. Relative root mean square errors (measurement error) and coefficients of variation (group-level variance) were calculated. GABA-edited data from 18 participants acquired from five voxels were used to examine the relationships between scan duration, SNR and quantitative outcomes in vivo. These relationships were then used to determine the sample sizes required to observe different effect sizes. In both simulated and in vivo data, SNR increased with the square root of the number of averages. Both measurement error and group-level variance were shown to follow an inverse-square-root function, indicating no significant impact of cumulative artifacts. Comparisons between the first two-thirds of the data and the full dataset showed no statistical difference in group-level variance. There was, however, some variability across the five voxels depending on SNR, which impacted the sample sizes needed to detect group differences in specific brain regions. Typical scan durations can be reduced if taking into account a statistically acceptable amount of variance and the magnitudes of predicted effects. While scan duration in GABA-edited MRS has typically been considered in terms of SNR, it is more appropriate to think in terms of the amount of measurement error and group-level variance that provides sufficient statistical power. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Fast differentiation of SIRS and sepsis from blood plasma of ICU patients using Raman spectroscopy.

    Science.gov (United States)

    Neugebauer, Ute; Trenkmann, Sabine; Bocklitz, Thomas; Schmerler, Diana; Kiehntopf, Michael; Popp, Jürgen

    2014-04-01

    Currently, there is no biomarker that can reliable distinguish between infectious and non-infectious systemic inflammatory response syndrome (SIRS). However, such a biomarker would be of utmost importance for early identification and stratification of patients at risk to initiate timely and appropriate antibiotic treatment. Within this proof of principle study, the high potential of Raman spectroscopy for the fast differentiation of non-infectious SIRS and sepsis is demonstrated. Blood plasma collected from 70 patients from the intensive care unit (31 patients with sepsis and 39 patients classified with SIRS without infection) was analyzed by means of Raman spectroscopy. A PCA-LDA based classification model was trained with Raman spectra from test samples and yielded for sepsis a sensitivity of 1.0 and specificity of 0.82. These results have been confirmed with an independent dataset (prediction accuracy 80%). Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Lattice-Assisted Spectroscopy: A Generalized Scanning Tunneling Microscope for Ultracold Atoms.

    Science.gov (United States)

    Kantian, A; Schollwöck, U; Giamarchi, T

    2015-10-16

    We propose a scheme to measure the frequency-resolved local particle and hole spectra of any optical lattice-confined system of correlated ultracold atoms that offers single-site addressing and imaging, which is now an experimental reality. Combining perturbation theory and time-dependent density matrix renormalization group simulations, we quantitatively test and validate this approach of lattice-assisted spectroscopy on several one-dimensional example systems, such as the superfluid and Mott insulator, with and without a parabolic trap, and finally on edge states of the bosonic Su-Schrieffer-Heeger model. We highlight extensions of our basic scheme to obtain an even wider variety of interesting and important frequency resolved spectra.

  6. Black carbon quantification in charcoal-enriched soils by differential scanning calorimetry

    Science.gov (United States)

    Hardy, Brieuc; Cornelis, Jean-Thomas; Leifeld, Jens

    2015-04-01

    Black carbon (BC), the solid residue of the incomplete combustion of biomass and fossil fuels, is ubiquitous in soil and sediments, fulfilling several environmental services such as long-term carbon storage. BC is a particularly important terrestrial carbon pool due to its large residence time compared to thermally unaltered organic matter, which is largely attributed to its aromatic structure. However, BC refers to a wide range of pyrogenic products from partly charred biomass to highly condensed soot, with a degree of aromaticity and aromatic condensation varying to a large extend across the BC continuum. As a result, BC quantification largely depends on operational definitions, with the extraction efficiency of each method varying across the entire BC range. In our study, we investigated the adequacy of differential scanning calorimetry (DSC) for the quantification of BC in charcoal-enriched soils collected in the topsoil of pre-industrial charcoal kilns in forest and cropland of Wallonia, Belgium, where charcoal residues are mixed to uncharred soil organic matter (SOM). We compared the results to the fraction of the total organic carbon (TOC) resisting to K2Cr2O7 oxidation, another simple method often used for BC measurement. In our soils, DSC clearly discriminates SOM from chars. SOM is less thermally stable than charcoal and shows a peak maximum around 295°C. In forest and agricultural charcoal-enriched soils, three peaks were attributed to the thermal degradation of BC at 395, 458 and 523°C and 367, 420 and 502 °C, respectively. In cropland, the amount of BC calculated from the DSC peaks is closely related (slope of the linear regression = 0.985, R²=0.914) to the extra organic carbon content measured at charcoal kiln sites relative to the charcoal-unaffected adjacent soils, which is a positive indicator of the suitability of DSC for charcoal quantification in soil. The first BC peak, which may correspond to highly degraded charcoal, contributes to a

  7. An Investigation of Thermal Characteristic of Mechanical Crimp Textured Polyester Yarn by Differential Scanning Calorimeter (DSC)

    Science.gov (United States)

    Bhattacharya, Someshwar S.; Shaikh, Tasnim N.; Pratap, Arun

    2010-06-01

    Deficiencies related to the lack of bulk in flat continuous filament yarns make them unsuitable for apparel, home textiles as well as other applications such as car seat covering. Hence, texturising is employed to impart lofty and bulky characteristics to them. The two major texturising techniques employed for polyester yarn are false-twist and air-jet texturising. Out of these earlier technique depends on the thermoplasticity of the yarn being textured whereas the later one demands subsequent amount of compressed air to carry out cold fluid texturising. A new concept of mechanical crimp texturising has been designed to overcome these limitations of commercially successful techniques. In this new technique, pre-twisted FDY (Fully Drawn Yarn) flat multifilament yarn has been subjected to the higher false-twisting (depending on yarn fineness) action under the condition of underfeed (depending on ductility of parent yarn). The torque caused due to high level of false-twisting, forces the filaments to follow helical path at a certain angle (depends on magnitude of twist and denier per filament) to the filament yarn longitudinal axis. Internal stresses arising in single filaments tend to bend the filament and take the shape of spatial helical spring. After the yarn has passed through the false twisting unit, the initial twist would reassert itself and lock the already formed crimpy convolutions in position. Mechanical crimp textured polyester yarns with different pre-twist and false-twist levels have been subjected to thermal stress analysis using differential Scanning Calorimeter (DSC) in heat-cool-heat mode. The samples were heated at a rate of 10°C/minute. Almost all samples appear to be crystalline in nature. However, the melting endotherm does not show sharp peak. Instead, the diffuse nature of the peak is a signature of a partial crystalline nature (48%) of the samples. After melting the specimens, cooling of the same leads to crystallization of the material

  8. Differential scanning calorimetry study on the binding of nucleic acids to dimyristoylphosphatidylcholine-sphingosine liposomes.

    Science.gov (United States)

    Kõiv, A; Mustonen, P; Kinnunen, P K

    1994-03-31

    Binding of DNA and RNA to sphingosine-containing dimyristoylphosphatidylcholine (DMPC) liposomes was characterized by differential scanning calorimetry. The thermal phase behaviour of neat DMPC liposomes was unaffected by the presence of the nucleic acids. However, significant alterations in the melting profiles of the DMPC/sphingosine composite membranes were produced by DNA and RNA, thus revealing their binding to the liposomes. For example, for 79:21 (molar ratio) DMPC/sphingosine liposomes a single endotherm at 29.1 degrees C with an enthalpy of 6.3 kcal/mol lipid was observed. In the presence of DNA at the nucleotide/sphingosine ratio of 0.6 this endotherm separated into three distinct peaks at 28.0, 31.4 and 35.1 degrees C, together with an approximately 22% reduction in the total enthalpy. Further increase in DNA concentration up to 1.5 nucleotides per sphingosine led to complete loss of the original heat absorption peak of the DMPC/sphingosine liposomes, while an endotherm at 34.3 degrees C with delta H of 2.7 kcal/mol developed. By visual inspection, rapid and extensive aggregation of the liposomes due to DNA was evident. Evidence for DNA-induced phase separation was also provided by compression isotherms of sphingosine containing DMPC monolayers recorded over an aqueous buffer both in the presence and absence of DNA. The effects of RNA on the thermal phase behaviour of the composite liposomes were qualitatively similar to those described above for DNA. Notably, the presence of eggPA abolished the nucleic acid induced heat capacity changes for DMPC/sphingosine liposomes probably because of neutralization of the positive charge of sphingosine. The binding of DNA to DMPC/sphingosine liposomes occurred both below and above the lipid phase transition temperature, as shown by fluorescence resonance energy transfer utilizing adriamycin-labelled DNA as a quencher and membrane incorporated pyrene-labelled phospholipid as a donor. However, the apparent binding to

  9. Energy dispersive x-ray diffractometry as a tool alternative to differential scanning calorimetry for investigating polymer phase transitions

    Science.gov (United States)

    Rossi-Albertini, V.; Isopo, A.; Caminiti, R.; Tentolini, U.

    2002-02-01

    Recently, a technique based on energy dispersive x-ray diffraction has been proposed to follow the polymer phase transitions. However, the potentialities of this method were not clear, as well as the experimental conditions in which it is more convenient than differential scanning calorimetry, generally used for the same purpose. In the present letter, the answer to this question is provided. It is shown that the two methods are complementary, rather than equivalent, the heating rate being the relevant parameter to establish which is preferable. The demonstration of this statement is given through the observation of the complex thermal properties of a reference sample studied in both ways at progressively lower heating rates. The connection between such unusual application of x-ray diffraction and the differential scanning calorimetry is discussed in terms of the two possible definitions of entropy.

  10. Monitoring early differentiation events in human embryonic stem cells by massively parallel signature sequencing and expressed sequence tag scan.

    Science.gov (United States)

    Miura, Takumi; Luo, Yongquan; Khrebtukova, Irina; Brandenberger, Ralph; Zhou, Daixing; Thies, R Scott; Vasicek, Tom; Young, Holly; Lebkowski, Jane; Carpenter, Melissa K; Rao, Mahendra S

    2004-12-01

    To identify genes that may be involved in the process of human embryonic stem cell (hESC) differentiation, we profiled gene expression by expressed sequenced tag (EST) enumeration and massively parallel signature sequencing (MPSS) using RNA samples from feeder-free cultures of undifferentiated (passages 40-50) and differentiated (day 14) H1, H7, and H9 lines. MPSS and EST scan analysis showed good concordance and identified a large number of genes that changed rapidly as cultures transition from a pluripotent to a differentiated state. These included known and unknown ES cell-specific genes as well as a large number of known genes that were altered as cells differentiate. A subset of genes that were either up- or down-regulated were selected and their differential expression confirmed by a variety of independent methods, including comparison of expression after further differentiation, publicly available databases, and direct assessments by reverse transcriptase (RT)-PCR and immunocytochemistry. The analysis identified markers unique to the hESC and embryoid bodies (hEBs) stage as well as signaling pathways that likely regulate differentiation. The data generated can be used to monitor the state of hESC isolated by different laboratories using independent methods and maintained under differing culture conditions.

  11. Composition measurement in substitutionally disordered materials by atomic resolution energy dispersive X-ray spectroscopy in scanning transmission electron microscopy.

    Science.gov (United States)

    Chen, Z; Taplin, D J; Weyland, M; Allen, L J; Findlay, S D

    2017-05-01

    The increasing use of energy dispersive X-ray spectroscopy in atomic resolution scanning transmission electron microscopy invites the question of whether its success in precision composition determination at lower magnifications can be replicated in the atomic resolution regime. In this paper, we explore, through simulation, the prospects for composition measurement via the model system of Al x Ga 1-x As, discussing the approximations used in the modelling, the variability in the signal due to changes in configuration at constant composition, and the ability to distinguish between different compositions. Results are presented in such a way that the number of X-ray counts, and thus the expected variation due to counting statistics, can be gauged for a range of operating conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. INTER-LAYER INTERACTION IN DOUBLE-WALLED CARBON NANOTUBES EVIDENCED BY SCANNING TUNNELING MICROSCOPY AND SPECTROSCOPY

    DEFF Research Database (Denmark)

    Giusca, Cristina E; Tison, Yann; Silva, S. Ravi P.

    2008-01-01

    and the overall electronic structure for double-walled carbon nanotubes, is demonstrated by our experiments, showing that the effect the inner tube has on the overall electronic structure of double-walled nanotubes cannot be neglected, and is key to the opto-electronic properties of the system. We postulate...... that previous analysis of the opto-electronic properties on multiple-walled carbon nanotubes based purely on the outer layer chirality of the tube needs significant modification based on new understanding brought forth with our analysis.......Scanning Tunneling Microscopy and Spectroscopy have been used in an attempt to elucidate the electronic structure of nanotube systems containing two constituent shells. Evidence for modified electronic structure due to the inter-layer interaction in double-walled carbon nanotubes is provided...

  13. A study of internal oxidation in carburized steels by glow discharge optical emission spectroscopy and scanning electron microscopy

    CERN Document Server

    An, X; Rainforth, W M; Chen, L

    2003-01-01

    The internal oxidation of Cr-Mn carburizing steel was studied. Internal oxidation was induced using a commercial carburizing process. Sputter erosion coupled with glow discharge optical emission spectroscopy (GDOES) was used to determine the depth profile elemental distribution within the internal oxidation layer (<10 mu m). In addition, scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) studies were carried out on selected sputter eroded surfaces. Oxide type was identified primarily by transmission electron microscopy (TEM). The carburized surface was found to consist of a continuous oxide layer, followed by a complex internal oxidation layer, where Cr and Mn oxides were found to populate grain boundaries in a globular form in the near surface region. At greater depths (5-10 mu m), Si oxides formed as a grain boundary network. The internal oxides (mainly complex oxides) grew quickly during the initial stages of the carburizing process (2 h, 800 deg. C+3 h, 930 deg. C). G...

  14. Differentiation of neotropical fish species with statistical analysis of fourier transform infrared photoacoustic spectroscopy data.

    Science.gov (United States)

    Almeida, Francylaine S; Lima, Sandro M; Andrade, Luis H C; Súarez, Yzel R

    2012-07-01

    Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was applied to nineteen fish species in Brazil's Upper Paraná River basin to identify differences in the structural composition of their scales. To differentiate the species, a canonical discriminant analysis was used to indicate the most important absorption peaks in the mid-infrared region. Significant differences were found in the chemical composition of scales among the studied fish species, with Wilk's lambda = 5.2 × 10(-6), F((13,18,394)) = 37.57, and P absorbance is related to the biological traits of each species. This procedure can also be used to complement evolutionary studies.

  15. Design and construction of a point-contact spectroscopy rig with lateral scanning capability

    Energy Technology Data Exchange (ETDEWEB)

    Tortello, M. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Torino 10129 (Italy); Park, W. K., E-mail: wkpark@illinois.edu; Ascencio, C. O.; Saraf, P.; Greene, L. H. [Department of Physics and Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

    2016-06-15

    The design and realization of a cryogenic rig for point-contact spectroscopy measurements in the needle-anvil configuration is presented. Thanks to the use of two piezoelectric nano-positioners, the tip can move along the vertical (z) and horizontal (x) direction and thus the rig is suitable to probe different regions of a sample in situ. Moreover, it can also form double point-contacts on different facets of a single crystal for achieving, e.g., an interferometer configuration for phase-sensitive measurements. For the later purpose, the sample holder can also host a Helmholtz coil for applying a small transverse magnetic field to the junction. A semi-rigid coaxial cable can be easily added for studying the behavior of Josephson junctions under microwave irradiation. The rig can be detached from the probe and thus used with different cryostats. The performance of this new probe has been tested in a Quantum Design PPMS system by conducting point-contact Andreev reflection measurements on Nb thin films over large areas as a function of temperature and magnetic field.

  16. Combined low-temperature scanning tunneling/atomic force microscope for atomic resolution imaging and site-specific force spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Udo; Albers, Boris J.; Liebmann, Marcus; Schwendemann, Todd C.; Baykara, Mehmet Z.; Heyde, Markus; Salmeron, Miquel; Altman, Eric I.; Schwarz, Udo D.

    2008-02-27

    The authors present the design and first results of a low-temperature, ultrahigh vacuum scanning probe microscope enabling atomic resolution imaging in both scanning tunneling microscopy (STM) and noncontact atomic force microscopy (NC-AFM) modes. A tuning-fork-based sensor provides flexibility in selecting probe tip materials, which can be either metallic or nonmetallic. When choosing a conducting tip and sample, simultaneous STM/NC-AFM data acquisition is possible. Noticeable characteristics that distinguish this setup from similar systems providing simultaneous STM/NC-AFM capabilities are its combination of relative compactness (on-top bath cryostat needs no pit), in situ exchange of tip and sample at low temperatures, short turnaround times, modest helium consumption, and unrestricted access from dedicated flanges. The latter permits not only the optical surveillance of the tip during approach but also the direct deposition of molecules or atoms on either tip or sample while they remain cold. Atomic corrugations as low as 1 pm could successfully be resolved. In addition, lateral drifts rates of below 15 pm/h allow long-term data acquisition series and the recording of site-specific spectroscopy maps. Results obtained on Cu(111) and graphite illustrate the microscope's performance.

  17. Development of a fountain detector for spectroscopy of secondary electrons in scanning electron microscopy

    Science.gov (United States)

    Agemura, Toshihide; Kimura, Takashi; Sekiguchi, Takashi

    2018-04-01

    The low-pass secondary electron (SE) detector, the so-called “fountain detector (FD)”, for scanning electron microscopy has high potential for application to the imaging of low-energy SEs. Low-energy SE imaging may be used for detecting the surface potential variations of a specimen. However, the detected SEs include a certain fraction of tertiary electrons (SE3s) because some of the high-energy backscattered electrons hit the grid to yield SE3s. We have overcome this difficulty by increasing the aperture ratio of the bias and ground grids and using the lock-in technique, in which the AC field with the DC offset was applied on the bias grid. The energy-filtered SE images of a 4H-SiC p–n junction show complex behavior according to the grid bias. These observations are clearly explained by the variations of Auger spectra across the p–n junction. The filtered SE images taken with the FD can be applied to observing the surface potential variation of specimens.

  18. Near-field scanning magneto-optical spectroscopy of Wigner molecules

    Energy Technology Data Exchange (ETDEWEB)

    Mintairov, A. M., E-mail: amintair@nd.edu; Rouvimov, S. [University of Notre Dame, Notre Dame, IN 46556 (United States); Ioffe Physical-Technical Institute of the Russian Academy of Sciences, Saint Petersburg, 194021 (Russian Federation); Kapaldo, J. [University of Notre Dame, Notre Dame, IN 46556 (United States); Merz, J. L.; Kalyygniy, N.; Mintairov, S. A.; Nekrasov, S.; Saly, R.; Vlasov, A. S. [Ioffe Physical-Technical Institute of the Russian Academy of Sciences, Saint Petersburg, 194021 (Russian Federation); Blundell, S. [SPSMS, UMR-E CEA/UJF-Grenoble 1, INAC, Grenoble, FR-38054 (France)

    2016-06-17

    We study the emission spectra of single self-organized InP/GaInP QDs (size 100-220 nm) using high-spatial-resolution, low-temperature (5 K) near-field scanning optical microscope (NSOM) operating at magnetic field strength B=0-10 T. The dots contain up to twenty electrons and represent natural Wigner molecules (WM). We observed vibronic-type shake-up structure in single electron QDs manifesting formation of two electron (2e) WM in photo-excited state. We found that relative intensities of the shake-up components described well by vibronic Frank-Condon factors giving for dots having parabolic confinement energy ħω{sub 0}=1.2-4 meV molecule bond lengths 40-140 nm. We used measurements of magnetic-field-induced shifts to distinguish emission of 2e-WM and singly charged exciton (trion). We also observed magnetic-field-induced molecular-droplet transition for two electron dot, emitting through doubly charge exciton (tetron) at zero magnetic field.

  19. Differential Epitope Mapping by STD NMR Spectroscopy To Reveal the Nature of Protein-Ligand Contacts.

    Science.gov (United States)

    Monaco, Serena; Tailford, Louise E; Juge, Nathalie; Angulo, Jesus

    2017-11-27

    Saturation transfer difference (STD) NMR spectroscopy is extensively used to obtain epitope maps of ligands binding to protein receptors, thereby revealing structural details of the interaction, which is key to direct lead optimization efforts in drug discovery. However, it does not give information about the nature of the amino acids surrounding the ligand in the binding pocket. Herein, we report the development of the novel method differential epitope mapping by STD NMR (DEEP-STD NMR) for identifying the type of protein residues contacting the ligand. The method produces differential epitope maps through 1) differential frequency STD NMR and/or 2) differential solvent (D 2 O/H 2 O) STD NMR experiments. The two approaches provide different complementary information on the binding pocket. We demonstrate that DEEP-STD NMR can be used to readily obtain pharmacophore information on the protein. Furthermore, if the 3D structure of the protein is known, this information also helps in orienting the ligand in the binding pocket. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  20. In situ differential reflectance spectroscopy of thin crystalline films of PTCDA on different substrates

    International Nuclear Information System (INIS)

    Proehl, Holger; Nitsche, Robert; Dienel, Thomas; Leo, Karl; Fritz, Torsten

    2005-01-01

    We report an investigation of the excitonic properties of thin crystalline films of the archetypal organic semiconductor PTCDA (3,4,9,10-perylenetetracarboxylic dianhydride) grown on poly- and single crystalline surfaces. A sensitive setup capable of measuring the optical properties of ultrathin organic molecular crystals via differential reflectance spectroscopy (DRS) is presented. This tool allows to carry out measurements in situ, i.e., during the actual film growth, and over a wide spectral range, even on single crystalline surfaces with high symmetry or metallic surfaces, where widely used techniques like reflection anisotropy spectroscopy (RAS) or fluorescence excitation spectroscopy fail. The spectra obtained by DRS resemble mainly the absorption of the films if transparent substrates are used, which simplifies the analysis. In the case of mono- to multilayer films of PTCDA on single crystalline muscovite mica(0001) and Au(111) substrates, the formation of the solid state absorption from monomer to dimer and further to crystal-like absorption spectra can be monitored

  1. The Kondo effect of an adatom in graphene and its scanning tunneling spectroscopy

    International Nuclear Information System (INIS)

    Li Lin; Ni Yangyang; Zhong Yin; Fang Tiefeng; Luo Honggang

    2013-01-01

    We study the Kondo effect of a single magnetic adatom on the surface of graphene. The unique linear dispersion relation near the Dirac points in graphene makes it easier for the magnetic atom to form a local magnetic moment, which simply means that the Kondo resonance can be observed in a wider parameter region than in the metallic host. Our study indicates that the Kondo resonance, whenever the chemical potential is tuned away from the Dirac points, can indeed occur ranging from the Kondo regime, to the mixed valence, even to the empty orbital regime defined in the conventional metal host. While the Kondo resonance appears as a sharp peak in the Kondo regime, it has a peak-dip structure and/or an anti-resonance in the mixed valence and empty orbital regimes, which result from the Fano resonance due to the significant background due to dramatic broadening of the impurity level in graphene. We also study the scanning tunneling microscopy (STM) spectra of the adatom and they show obvious particle–hole asymmetry when the chemical potential is tuned by the gate voltages applied to the graphene. Finally, we explore the influence of the direct tunneling channel between the STM tip and the graphene on the Kondo resonance and find that the lineshape of the Kondo resonance is unaffected, which can be attributed to an unusually large asymmetry factor in graphene. Our study indicates that graphene is an ideal platform to systematically study Kondo physics and these results are useful to further stimulate relevant experimental studies on the system. (paper)

  2. Role of CT scan in differentiating the type of colorectal cancer

    Directory of Open Access Journals (Sweden)

    Li ZH

    2017-04-01

    Full Text Available Zhen-Hui Li,1,* Ding-Yun You,2,* De-Pei Gao,1 Guang-Jun Yang,1 Xing-Xiang Dong,1 Da-Fu Zhang,1 Ying-Ying Ding1 1Department of Radiology, The Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province, Kunming, 2Department of Science and Technology, Kunming Medical University, Kunming, Yunnan, People’s Republic of China *These authors contributed equally to this work Objectives: Most colorectal cancers are classical adenocarcinomas (AC, and less frequent subtypes include mucinous adenocarcinomas (MAC and signet-ring cell carcinomas (SC. The purpose of this study was to evaluate the computed tomography (CT findings that can help to differentiate MAC and SC from AC.Methods: CT scans of 168 patients with pathologically proven MAC and 67 patients with pathologically proven SC were analyzed, and 220 patients with classical AC were also included as a control group. CT findings of the three groups were compared and contrasted in terms of the bowel involvement patterns, contrast enhancement patterns, and presence or absence of bowel obstruction, intratumoral calcification, pericolic fat infiltration, and local tumor extension to adjacent organs. Statistical analyses were made by using the one-way analysis of variance, least significant difference test, and Pearson’s chi-square test.Results: Compared with classical AC, the MAC showed more severe (6.29±2.69 cm vs 4.57±1.74 cm, P<0.001 and higher percentage of occurrence of eccentric bowel-wall thickening (37.2% vs 11.5%, P<0.001. Heterogeneous contrast enhancement was most common in MAC (P<0.01, and MAC showed more areas with hypoattenuation (P<0.001. The presence of intratumoral calcification was most frequent in MAC (17.9% vs 2% vs 6.8% (P<0.001; the SC also were more severe (5.75±2.28 cm vs 4.57±1.74 cm. P=0.001 than AC, but SC tend to show more cases of concentric even bowel-wall thickening (67.2%; homogeneous contrast enhancement was most common in SC (P<0

  3. Development and Testing of a Scanning Differential Absorption Lidar For Carbon Sequestration Site Monitoring

    Science.gov (United States)

    Soukup, B.; Johnson, W.; Repasky, K. S.; Carlsten, J. L.

    2013-12-01

    A scanning differential absorption lidar (DIAL) instrument for carbon sequestration site monitoring is under development and testing at Montana State University. The laser transmitter uses two tunable discrete mode laser diodes (DMLD) operating in the continuous wave (cw) mode with one locked to the on-line absorption wavelength at 1571.4067 nm and the second operating at the off-line wavelength at 1571.2585 nm. Two in-line fiber optic switches are used to switch between on-line and off-line operation. After the fiber optic switches, an acousto-optic modulator (AOM) is used to generate a pulse train used to injection seed an erbium doped fiber amplifier (EDFA) to produce eye-safe laser pulses with maximum pulse energies of 66 J and a pulse repetition frequency of 15 kHz. The DIAL receiver uses a 28 cm diameter Schmidt-Cassegrain telescope to collect that backscattered light, which is then monitored using a fiber coupled photo-multiplier tube (PMT) module operating in the photon counting mode. The PMT has a 3% quantum efficiency, a dark count rate of 90 kHz, and a maximum count rate of 1 MHz. Recently, a fiber coupled avalanche photodiode (APD) operating in the geiger mode has been incorporated into the DIAL receiver. The APD has a quantum efficiency of 10%, a dark count rate of 10 kHz, and a maximum count rate of 1 MHz and provides a much larger dynamic range than the PMT. Both the PMT and APD provide TTL logic pulses that are monitored using a multichannel scaler card used to count the return photons as a function of time of flight and are thus interchangeable. The DIAL instrument was developed at the 1.571 m wavelength to take advantage of commercial-off-the-shelf components. The instrument is operated using a custom Labview program that switches to the DMLD operating at the on-line wavelength, locks this laser to a user defined wavelength setting, and collects return signals for a user defined time. The control program switches to the DMLD operating at the off

  4. Spectral studies of ocean water with space-borne sensor SCIAMACHY using Differential Optical Absorption Spectroscopy (DOAS

    Directory of Open Access Journals (Sweden)

    M. Vountas

    2007-09-01

    Full Text Available Methods enabling the retrieval of oceanic parameter from the space borne instrumentation Scanning Imaging Absorption Spectrometer for Atmospheric ChartographY (SCIAMACHY using Differential Optical Absorption Spectroscopy (DOAS are presented. SCIAMACHY onboard ENVISAT measures back scattered solar radiation at a spectral resolution (0.2 to 1.5 nm. The DOAS method was used for the first time to fit modelled Vibrational Raman Scattering (VRS in liquid water and in situ measured phytoplankton absorption reference spectra to optical depths measured by SCIAMACHY. Spectral structures of VRS and phytoplankton absorption were clearly found in these optical depths. Both fitting approaches lead to consistent results. DOAS fits correlate with estimates of chlorophyll concentrations: low fit factors for VRS retrievals correspond to large chlorophyll concentrations and vice versa; large fit factors for phytoplankton absorption correspond with high chlorophyll concentrations and vice versa. From these results a simple retrieval technique taking advantage of both measurements is shown. First maps of global chlorophyll concentrations were compared to the corresponding MODIS measurements with very promising results. In addition, results from this study will be used to improve atmospheric trace gas DOAS-retrievals from visible wavelengths by including these oceanographic signatures.

  5. Immunohistochemical Analysis of Neuroendocrine (NE) Differentiation in Testicular Germ Cell Tumors (GCTs): Use of Confocal Laser Scanning Microscopy (CLSM) to Demonstrate Direct NE Differentiation from GCTs

    International Nuclear Information System (INIS)

    Kumaki, Nobue; Umemura, Shinobu; Kajiwara, Hiroshi; Itoh, Johbu; Itoh, Yoshiko; Osamura, R.Yoshiyuki

    2007-01-01

    Neuroendocrine (NE) differentiation is infrequent in testicular tumors and its histogenesis is not well understood. The present study is aimed at elucidating the pathway of neuroendocrine differentiation in germ cell tumors (GCTs) of the testis. In the analysis of 46 germ cell tumor components from 23 testicular tumors, we focused on GCTs with neuroendocrine differentiation, 7 teratoma, 1 embryonal carcinoma and 1 neuroendocrine carcinoma by immunohistochemical study and confocal laser scanning microscopy (CLSM) analysis. NE marker positive cells were noted in the tumor with collision of teratoma and embryonal carcinoma (E&T tumor), in the immature columnar cells of transitional form of embryonal carcinoma to teratoma (E-T cells) and neuroendocrine carcinoma cells, in addition to the well known mature intestinal mucosa in teratoma. Double staining for a NE marker (CGA) and a germ cell marker (PLAP) demonstrated the localization of both proteins in the same E-T cells confirmed by CLSM. Another finding, indicating the intimate relation between embryonal carcinoma and neuroendcrine differentiation, is that neuroendocrine carcinoma expressed a marker of embryonal carcinoma, CD30. The present results indicated that the NE cells might be differentiated from embryonal carcinoma, a view that has not been proposed before, but that is made in the present study using CLSM

  6. Gradient temperature Raman spectroscopy identifies flexible sites in proline and alanine peptides

    Science.gov (United States)

    Continuous thermo dynamic Raman spectroscopy (TDRS) applies the temperature gradients utilized in differential scanning calorimetry (DSC) to Raman spectroscopy, providing a straightforward technique to identify molecular rearrangements that occur just prior to phase transitions. Herein we apply TDRS...

  7. Aqueous solutions of proline and NaCl studied by differential scanning calorimetry at subzero temperatures

    DEFF Research Database (Denmark)

    Rasmussen, Peter Have; Jørgensen, Bo; Nielsen, Jette

    1997-01-01

    was not observed during freezing or melting which shows that proline has the ability to stay in solution at subzero temperatures. Samples containing proline-NaCl-water were also investigated by DSC and it was shown that the solubility of proline is maintained in aqueous salt solutions at temperatures as low as -60....../w) indicating a high water solubility of proline at subzero temperatures. No glass transition was observed within the concentration range 0.9-40.1 wt% (w/w), neither at a low scanning rate of 2.5 degrees C/min nor at a higher scanning rate of 10 degrees C/min. Eutectic crystallization of proline...

  8. Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1968-01-01

    This booklet discusses spectroscopy, the study of absorption of radiation by matter, including X-ray, gamma-ray, microwave, mass spectroscopy, as well as others. Spectroscopy has produced more fundamental information to the study of the detailed structure of matter than any other tools.

  9. Differentiating Oriental Fruit Moth and Codling Moth (Lepidoptera: Tortricidae) Larvae Using Near-Infrared Spectroscopy.

    Science.gov (United States)

    Siegwart, Myriam; Bouvier, Floriane; Maugin, Sandrine; Lecomte, Alain; Lavigne, Claire

    2015-02-01

    Cydia pomonella (L.) and Cydia molesta (Busck) (Lepidoptera: Tortricidae) are two important lepidopteran pests that may co-occur in apple orchards and are difficult to differentiate in the larval stage. We investigate the possibility of using near-infrared spectroscopy (NIRS) coupled with partial least squares analysis to distinguish the larvae of the two species. We further assess whether wild individuals can be differentiated using laboratory strains of the two species for model calibration. The NIRS spectra of C. molesta and C. pomonella differed most in the wavelengths between 1,142 and 1,338 nm. Using these wavelengths, partial least squares analysis allowed the differentiation of C. molesta and C. pomonella at the larval stage with very low error, but only as long as both the calibration and prediction sets for individuals had the same origin (either both from the laboratory or both from the field). Errors that appeared when using laboratory individuals for calibration were owing to the divergence of the C. pomonella laboratory strain, most likely following evolution during rearing. Thus, NIRS appears to be a promising tool for the easy and rapid identification of individuals in the field, provided that it is calibrated based on a subset of field individuals. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Spectroscopy

    CERN Document Server

    Walker, S

    1976-01-01

    The three volumes of Spectroscopy constitute the one comprehensive text available on the principles, practice and applications of spectroscopy. By giving full accounts of those spectroscopic techniques only recently introduced into student courses - such as Mössbauer spectroscopy and photoelectron spectroscopy - in addition to those techniques long recognised as being essential in chemistry teaching - sucha as e.s.r. and infrared spectroscopy - the book caters for the complete requirements of undergraduate students and at the same time provides a sound introduction to special topics for graduate students.

  11. A real time analysis of the self-assembly process using thermal analysis inside the differential scanning calorimeter instrument.

    Science.gov (United States)

    Roy, Debmalya; Shastri, Babita; Mukhopadhyay, K

    2012-07-12

    The supramolecular assembly of the regioregular poly-3-hexylthiophene (rr-P3HT) in solution has been investigated thoroughly in the past. In the current study, our focus is on the enthalpy of nanofiber formation using thermal analysis techniques by performing the self-assembly process inside the differential scanning calorimetry (DSC) instrument. Thermogravimetric analysis (TGA) was carried out to check the concentration of the solvent during the self-assembly process of P3HT in p-xylene. Ultraviolet visible (UV-vis) spectophotometric technique, small-angle X-ray scattering (SAXS) experiment, atomic force microscopic (AFM), and scanning electron microscopic (SEM) images were used to characterize the different experimental yields generated by cooling the reaction mixture at desired temperatures. Comparison of the morphologies of self-assembled products at different fiber formation temperatures gives us an idea about the possible crystallization parameters which could affect the P3HT nanofiber morphology.

  12. Change in physical structure of a phenol-spiked sapric histosol observed by Differential Scanning Calorimetry

    Science.gov (United States)

    Ondruch, Pavel; Kucerik, Jiri; Schaumann, Gabriele E.

    2014-05-01

    Interactions of pollutants with soil organic matter (SOM), their fate and transformation are crucial for understanding of soil functions and properties. In past, many papers dealing with sorption of organic and inorganic compounds have been published. However, their aim was almost exceptionally fo-cused on the pollutants themselves, determination of sorption isotherms and influence of external factors, while the change in SOM supramolecular structure was usually ignored. The SOM structure is, however, very important, since the adsorbed pollutant might have a significant influence on soil stability and functions. Differential scanning calorimetry (DSC) represents a technique, which has been successfully used to analyze the physical structure and physico-chemical aging of SOM. It has been found out that water molecules progressively stabilize SOM (water molecule bridge (WaMB)) (Schaumann & Bertmer 2008). Those bridges connect and stabilize SOM and can be disrupted at higher temperature (WaMB transition; (Kunhi Mouvenchery et al. 2013; Schaumann et al. 2013). In the same temperature region melting of aliphatic moieties can be observed (Hu et al. 2000; Chilom & Rice 2005; Kucerik et al. submitted 2013). In this work, we studied the effect of phenol on the physical structure of sapric histosol. Phenol was dissolved in various solvents (water, acetone, hexane, methanol) and added to soils. After the evaporation of solvents by air drying, the sample was equilibrated at 76% relative humidity for 3 weeks. Using DSC, we investigated the influence of phenol on histosol structure and time dependence of melting temperature of aliphatic moieties and WaMB transition. While addition of pure organic solvent only resulted in slightly increased transition temperatures, both melting temperature and WaMB transition temperature were significantly reduced in most cases if phenol was dissolved in these solvents. Water treatment caused a decrease in WaMB transition temperature but

  13. Interactions in interesterified palm and palm kernel oils mixtures. II – Microscopy and Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Grimaldi, Renato

    2001-12-01

    Full Text Available Palm oil (PO and palm kernel oil (PKO compositions (100/0, 80/20, 60/40, 50/50, 40/60, 20/80 and 0/100 were interesterified in laboratory scale under predetermined conditions (0.4% sodium metoxide, 20 minutes, 100ºC. The fourteen samples, before and after interesterification, were characterized by Polarized Light Microscopy and Differential Scanning Calorimetry (DSC. Results showed the effect of various factors on the form and width of crystals. The mean area of crystals revealed the increase of crystals when PKO was added, with values varying from 2.7 x 10E3 µm2 to PO and 1.8 x 10E6 µm2 to PKO. After interesterification, the crystal widths were lower at PO/PKO 100/0, 80/20, 60/40, 20/80 fractions and were higher to anothers. The beta-prime polimorphic form was observed in the pure palm oil sample. The results showed in melting curves, onset values from –19.6ºC to more unsaturated peaks until 20.7ºC to more saturated ones. The higher values to more saturated peak in a melting curve to palm oil, 38.7 J.g-1 before and 48.4 J.g-1 after interesterification, showed a mores table saturated group. I n a genera l way, t h e interesterification promoted an increase of crystallization rate and a better compatibility between PO/PKO fractions.Fueron interesterificados en el laboratorio mezclas de aceite de palma (PO y aceite de palmiste (PKO en diferentes proporciones (100/0, 80/20, 60/40, 50/50, 40/60, 20/80 y 0/100 bajo condiciones predeterminadas (0.4% metoxido de sodio, 20 minutos, 100ºC. Las catorce muestras fueron caracterizadas antes y después de la interesterificación por Microscopía de Luz Polarizada y por Calorimetría Diferencial de Barrido (DSC. Los resultados mostraron el efecto de varios factores sobre la forma y anchura de los cristales. El área media de los cristales revela el aumento de tamaño de los mismos cuando aumenta la proporción de PKO, con valores que varían entre 2.7 x 10E3 µm2 para PO y 1.8 x 10E

  14. Gallium scanning in differentiating malignant from benign asbestos-related pleural disease

    International Nuclear Information System (INIS)

    Teirstein, A.S.; Chahinian, P.; Goldsmith, S.J.; Sorek, M.

    1986-01-01

    In order to assess the utility of 67gallium citrate in delineating malignant pleural mesothelioma from benign asbestos-related pleural disease, 49 patients with malignant mesothelioma and 16 with benign asbestos-related pleural disease were studied. Seven patients with malignant mesothelioma had no history of asbestos exposure, while the remaining 58 patients were exposed. Forty-three of the 49 patients (88%) with malignant mesothelioma had a positive 67gallium scan including 36 of the 42 (86%) patients with asbestos exposure and all 7 patients without a history of asbestos exposure. Three of 16 patients (19%) with benign asbestos-related pleural disease had a positive scan. 67Gallium radionuclide imaging is nonspecific but may be valuable in noninvasive monitoring of asbestos-exposed populations, which have a high risk for the late development of benign and/or malignant pleural disease

  15. Detection of a new 'nematic-like' phase in liquid crystal-amphiphile mixture by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Dan, Kaustabh, E-mail: kaustabhdan@gmail.com; Roy, Madhusudan, E-mail: kaustabhdan@gmail.com; Datta, Alokmay, E-mail: kaustabhdan@gmail.com [Surface Physics and Materials Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar Block, Sector 1, Kolkata-700064 (India)

    2014-04-24

    Differential Scanning Calorimetry (DSC) studies on phase transitions of the pure liquid crystalline material N-4-methoxybenzylidene-4-butylaniline (MBBA) and mixtures of MBBA and the amphiphile Stearic Acid (StA) show significant changes in the behavior of mixture from pure MBBA, as regards the nematic-isotropic (N-I) transition temperature (T{sub c}) and other thermodynamic parameters like enthalpy, specific heat and activation energy with concentration of StA. In particular, the convexity of the Arrhenius plot in pure MBBA vanishes with StA concentration pointing to the formation of a new, perhaps 'nematic-like', phase in the mixtures.

  16. Differentiation between eclampsia and cerebrovascular disorders by brain CT scan in pregnant patients with convulsive seizures

    International Nuclear Information System (INIS)

    Eguchi, Katsuto; Lin, Yaw-Tyng; Noda, Kiyofumi; Saeki, Kazuhiko; Yonezawa, Masaru; Sekiba, Kaoru; Ochiai, Youji

    1987-01-01

    Six pregnant women with convulsions between 25 to 40 weeks of gestation were experienced. Among them, 4 patients were diagnosed as having intracranial hemorrhage and two as simple eclampsia. With the aid of brain CT scan, one case of arteriovenous malformation was detected and treated surgically with good prognosis for both the mother and the fetus. Two patients were diagnosed to have cerebral hemorrhage with subsequent penetration into the lateral ventricles and were treated conservatively. Their fetuses were delivered alive by cesarean section, but the mothers expired. The other patient with cerebral hemorrhage was treated surgically, and both the mother and the fetus survived. One of the simple eclampsia patients was noted to have a growth retarded fetus at 32 weeks of pregnancy with subsequent intra-uterine death, but the mother recovered after conservative treatment. Another patient at 40 weeks of pregnancy was also treated conservatively and both the fetus and the mother survived. Brain CT scan findings differed between these two eclampsia patients; local brain edema for the second patient and generalized brain edema for the first patient. Thus more active application of brain CT scan is recommended in managing pregnant patients with convulsions. (author)

  17. Differentiation between eclampsia and cerebrovascular disorders by brain CT scan in pregnant patients with convulsive seizures

    Energy Technology Data Exchange (ETDEWEB)

    Eguchi, Katsuto; Lin, Yaw-Tyng; Noda, Kiyofumi; Saeki, Kazuhiko; Yonezawa, Masaru; Sekiba, Kaoru; Ochiai, Youji

    1987-06-01

    Six pregnant women with convulsions between 25 to 40 weeks of gestation were experienced. Among them, 4 patients were diagnosed as having intracranial hemorrhage and two as simple eclampsia. With the aid of brain CT scan, one case of arteriovenous malformation was detected and treated surgically with good prognosis for both the mother and the fetus. Two patients were diagnosed to have cerebral hemorrhage with subsequent penetration into the lateral ventricles and were treated conservatively. Their fetuses were delivered alive by cesarean section, but the mothers expired. The other patient with cerebral hemorrhage was treated surgically, and both the mother and the fetus survived. One of the simple eclampsia patients was noted to have a growth retarded fetus at 32 weeks of pregnancy with subsequent intra-uterine death, but the mother recovered after conservative treatment. Another patient at 40 weeks of pregnancy was also treated conservatively and both the fetus and the mother survived. Brain CT scan findings differed between these two eclampsia patients; local brain edema for the second patient and generalized brain edema for the first patient. Thus more active application of brain CT scan is recommended in managing pregnant patients with convulsions.

  18. Comparison of nanoparticle diffusion using fluorescence correlation spectroscopy and differential dynamic microscopy within concentrated polymer solutions

    Science.gov (United States)

    Shokeen, Namita; Issa, Christopher; Mukhopadhyay, Ashis

    2017-12-01

    We studied the diffusion of nanoparticles (NPs) within aqueous entangled solutions of polyethylene oxide (PEO) by using two different optical techniques. Fluorescence correlation spectroscopy, a method widely used to investigate nanoparticle dynamics in polymer solution, was used to measure the long-time diffusion coefficient (D) of 25 nm radius particles within high molecular weight, Mw = 600 kg/mol PEO in water solutions. Differential dynamic microscopy (DDM) was used to determine the wave-vector dependent dynamics of NPs within the same polymer solutions. Our results showed good agreement between the two methods, including demonstration of normal diffusion and almost identical diffusion coefficients obtained by both techniques. The research extends the scope of DDM to study the dynamics and rheological properties of soft matter at a nanoscale. The measured diffusion coefficients followed a scaling theory, which can be explained by the coupling between polymer dynamics and NP motion.

  19. Raster image correlation spectroscopy (RICS) for measuring fast protein dynamics and concentrations with a commercial laser scanning confocal microscope.

    Science.gov (United States)

    Brown, C M; Dalal, R B; Hebert, B; Digman, M A; Horwitz, A R; Gratton, E

    2008-01-01

    Raster image correlation spectroscopy (RICS) is a new and novel technique for measuring molecular dynamics and concentrations from fluorescence confocal images. The RICS technique extracts information about molecular dynamics and concentrations from images of living cells taken on commercial confocal systems. Here we develop guidelines for performing the RICS analysis on an analogue commercial laser scanning confocal microscope. Guidelines for typical instrument settings, image acquisition settings and analogue detector characterization are presented. Using appropriate instrument/acquisition parameters, diffusion coefficients and concentrations can be determined, even for highly dynamic dye molecules in solution. Standard curves presented herein demonstrate the ability to detect protein concentrations as low as approximately 2 nM. Additionally, cellular measurements give accurate values for the diffusion of paxillin-enhanced-green fluorescent protein (EGFP), an adhesion adaptor molecule, in the cytosol of the cell and also show slower paxillin dynamics near adhesions where paxillin interacts with immobile adhesion components. Methods are presented to account for bright immobile structures within the cell that dominate spatial correlation functions; allowing the extraction of fast protein dynamics within and near these structures. A running average algorithm is also presented to address slow cellular movement or movement of cellular features such as adhesions. Finally, methods to determine protein concentration in the presence of immobile structures within the cell are presented. A table is presented giving guidelines for instrument and imaging setting when performing RICS on the Olympus FV300 confocal and these guidelines are a starting point for performing the analysis on other commercial confocal systems.

  20. A study of internal oxidation in carburized steels by glow discharge optical emission spectroscopy and scanning electron microscopy

    International Nuclear Information System (INIS)

    An, X; Cawley, J.; Rainforth, W.M.; Chen, L.

    2003-01-01

    The internal oxidation of Cr-Mn carburizing steel was studied. Internal oxidation was induced using a commercial carburizing process. Sputter erosion coupled with glow discharge optical emission spectroscopy (GDOES) was used to determine the depth profile elemental distribution within the internal oxidation layer (<10 μm). In addition, scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) studies were carried out on selected sputter eroded surfaces. Oxide type was identified primarily by transmission electron microscopy (TEM). The carburized surface was found to consist of a continuous oxide layer, followed by a complex internal oxidation layer, where Cr and Mn oxides were found to populate grain boundaries in a globular form in the near surface region. At greater depths (5-10 μm), Si oxides formed as a grain boundary network. The internal oxides (mainly complex oxides) grew quickly during the initial stages of the carburizing process (2 h, 800 deg. C+3 h, 930 deg. C). GDOES proved to be an excellent tool for the quantification of oxidation and element distribution as a function of depth, particularly when combined with SEM and TEM to identify oxide type and morphology

  1. Scanning electron microscopy and X-ray energy dispersive spectroscopy - useful tools in the analysis of pharmaceutical products

    Science.gov (United States)

    Sarecka-Hujar, Beata; Balwierz, Radoslaw; Ostrozka-Cieslik, Aneta; Dyja, Renata; Lukowiec, Dariusz; Jankowski, Andrzej

    2017-11-01

    The quality of the drug, its purity and identification of degradation products provide the highest quality of pharmaceutical products. The energy dispersive spectroscopy (EDS) method analyses the percentage of each element form as well as their distribution, and morphological characteristics of the drug form. We analysed the usefulness of EDS method in testing orally disintegrating tablets (ODT) with trimetazidine hydrochloride with high resolution scanning electron microscopy (SEM, SUPRA25 Carl Zeiss company) with spectrophotometer equipped with an X-ray energy dispersion (EDAX Company). The samples of the analysed tablets were imaged after applying conductive layers of gold on their surface. In the EDS analysis the compositions of each sample of the obtained tablets were observed to be virtually identical. The differences in the content of carbon and oxygen came from differences in the composition of particular tablets. The presence of gold in the composition resulted from the sputtering the surface of tablets with gold during the analysis. Knowing the composition of the tablet, SEM-EDS method helps to locate and identify the impurities and degradation products of the compounds, leading to a better understanding of the mechanisms of their formation.

  2. Application of two-dimensional J-resolved nuclear magnetic resonance spectroscopy to differentiation of beer

    International Nuclear Information System (INIS)

    Khatib, Alfi; Wilson, Erica G.; Kim, Hye Kyong; Lefeber, Alfons W.M.; Erkelens, Cornelis; Choi, Young Hae; Verpoorte, Robert

    2006-01-01

    A number of ingredients in beer that directly or indirectly affect its quality require an unbiased wide-spectrum analytical method that allows for the determination of a wide array of compounds for its efficient control. 1 H nuclear magnetic resonance (NMR) spectroscopy is a method that clearly meets this description as the broad range of compounds in beer is detectable. However, the resulting congestion of signals added to the low resolution of 1 H NMR spectra makes the identification of individual components very difficult. Among two-dimensional (2D) NMR techniques that increase the resolution, J-resolved NMR spectra were successfully applied to the analysis of 2-butanol extracts of beer as overlapping signals in 1 H NMR spectra were fully resolved by the additional axis of the coupling constant. Principal component analysis based on the projected J-resolved NMR spectra showed a clear separation between all of the six brands of pilsner beer evaluated in this study. The compounds responsible for the differentiation were identified by 2D NMR spectra including correlated spectroscopy and heteronuclear multiple bond correlation spectra together with J-resolved spectra. They were identified as nucleic acid derivatives (adenine, uridine and xanthine), amino acids (tyrosine and proline), organic acid (succinic and lactic acid), alcohol (tyrosol and isopropanol), cholines and carbohydrates

  3. Application of two-dimensional J-resolved nuclear magnetic resonance spectroscopy to differentiation of beer

    Energy Technology Data Exchange (ETDEWEB)

    Khatib, Alfi [Division of Pharmacognosy, Section Metabolomics, Institute of Biology, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Wilson, Erica G. [Division of Pharmacognosy, Section Metabolomics, Institute of Biology, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Kim, Hye Kyong [Division of Pharmacognosy, Section Metabolomics, Institute of Biology, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Lefeber, Alfons W.M. [Division of NMR, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Erkelens, Cornelis [Division of NMR, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Choi, Young Hae [Division of Pharmacognosy, Section Metabolomics, Institute of Biology, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands)]. E-mail: y.choi@chem.leidenuniv.nl; Verpoorte, Robert [Division of Pharmacognosy, Section Metabolomics, Institute of Biology, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands)

    2006-02-16

    A number of ingredients in beer that directly or indirectly affect its quality require an unbiased wide-spectrum analytical method that allows for the determination of a wide array of compounds for its efficient control. {sup 1}H nuclear magnetic resonance (NMR) spectroscopy is a method that clearly meets this description as the broad range of compounds in beer is detectable. However, the resulting congestion of signals added to the low resolution of {sup 1}H NMR spectra makes the identification of individual components very difficult. Among two-dimensional (2D) NMR techniques that increase the resolution, J-resolved NMR spectra were successfully applied to the analysis of 2-butanol extracts of beer as overlapping signals in {sup 1}H NMR spectra were fully resolved by the additional axis of the coupling constant. Principal component analysis based on the projected J-resolved NMR spectra showed a clear separation between all of the six brands of pilsner beer evaluated in this study. The compounds responsible for the differentiation were identified by 2D NMR spectra including correlated spectroscopy and heteronuclear multiple bond correlation spectra together with J-resolved spectra. They were identified as nucleic acid derivatives (adenine, uridine and xanthine), amino acids (tyrosine and proline), organic acid (succinic and lactic acid), alcohol (tyrosol and isopropanol), cholines and carbohydrates.

  4. Rapid differentiation of Ghana cocoa beans by FT-NIR spectroscopy coupled with multivariate classification

    Science.gov (United States)

    Teye, Ernest; Huang, Xingyi; Dai, Huang; Chen, Quansheng

    2013-10-01

    Quick, accurate and reliable technique for discrimination of cocoa beans according to geographical origin is essential for quality control and traceability management. This current study presents the application of Near Infrared Spectroscopy technique and multivariate classification for the differentiation of Ghana cocoa beans. A total of 194 cocoa bean samples from seven cocoa growing regions were used. Principal component analysis (PCA) was used to extract relevant information from the spectral data and this gave visible cluster trends. The performance of four multivariate classification methods: Linear discriminant analysis (LDA), K-nearest neighbors (KNN), Back propagation artificial neural network (BPANN) and Support vector machine (SVM) were compared. The performances of the models were optimized by cross validation. The results revealed that; SVM model was superior to all the mathematical methods with a discrimination rate of 100% in both the training and prediction set after preprocessing with Mean centering (MC). BPANN had a discrimination rate of 99.23% for the training set and 96.88% for prediction set. While LDA model had 96.15% and 90.63% for the training and prediction sets respectively. KNN model had 75.01% for the training set and 72.31% for prediction set. The non-linear classification methods used were superior to the linear ones. Generally, the results revealed that NIR Spectroscopy coupled with SVM model could be used successfully to discriminate cocoa beans according to their geographical origins for effective quality assurance.

  5. Differentiation of different mixed Listeria strains and also acid-injured, heat-injured, and repaired cells of Listeria monocytogenes using fourier transform infrared spectroscopy.

    Science.gov (United States)

    Nyarko, Esmond; Donnelly, Catherine

    2015-03-01

    Fourier transform infrared (FT-IR) spectroscopy was used to differentiate mixed strains of Listeria monocytogenes and mixed strains of L. monocytogenes and Listeria innocua. FT-IR spectroscopy was also applied to investigate the hypothesis that heat-injured and acid-injured cells would return to their original physiological integrity following repair. Thin smears of cells on infrared slides were prepared from cultures for mixed strains of L. monocytogenes, mixed strains of L. monocytogenes and L. innocua, and each individual strain. Heat-injured and acid-injured cells were prepared by exposing harvested cells of L. monocytogenes strain R2-764 to a temperature of 56 ± 0.2°C for 10 min or lactic acid at pH 3 for 60 min, respectively. Cellular repair involved incubating aliquots of acid-injured and heat-injured cells separately in Trypticase soy broth supplemented with 0.6% yeast extract for 22 to 24 h; bacterial thin smears on infrared slides were prepared for each treatment. Spectral collection was done using 250 scans at a resolution of 4 cm(-1) in the mid-infrared wavelength region. Application of multivariate discriminant analysis to the wavelength region from 1,800 to 900 cm(-1) separated the individual L. monocytogenes strains. Mixed strains of L. monocytogenes and L. monocytogenes cocultured with L. innocua were successfully differentiated from the individual strains when the discriminant analysis was applied. Different mixed strains of L. monocytogenes were also successfully separated when the discriminant analysis was applied. A data set for injury and repair analysis resulted in the separation of acid-injured, heat-injured, and intact cells; repaired cells clustered closer to intact cells when the discriminant analysis (1,800 to 600 cm(-1)) was applied. FT-IR spectroscopy can be used for the rapid source tracking of L. monocytogenes strains because it can differentiate between different mixed strains and individual strains of the pathogen.

  6. Pulmonary aspergilloma: A rare differential diagnosis to lung cancer after positive FDG PET scan

    Directory of Open Access Journals (Sweden)

    Franziska Spycher

    2014-01-01

    Full Text Available Early diagnosis and treatment of lung cancer, one of the leading causes of cancer-related death, is important to improve morbidity and mortality. Therefore any suspect solitary pulmonary nodule should prompt the pursuit for a definitive histological diagnosis. We describe the case of a 55-years-old male ex-smoker, who was admitted to our hospital due to recurrent hemoptysis and dry cough. A CT scan showed an irregular nodule of increasing size (28 mm in diameter in the left lower lobe (LLL. A whole body PET-CT scan (643 MBq F-18 FDG i.v. was performed and confirmed an avid FDG uptake of the nodule in the LLL, highly suspicious of lung cancer, without any evidence of lymphogenic or hematogenic metastasis. Bronchoscopy was not diagnostic and due to severe adhesions after prior chest trauma and the central location of the nodule, a lobectomy of the LLL was performed. Surprisingly, histology showed a simple aspergilloma located in a circumscribed bronchiectasis with no evidence of malignancy. This is a report of an informative example of an aspergilloma, which presented with symptoms and radiological features of malignant lung cancer.

  7. Differential scanning calorimetry as a screening technique in compatibility studies of acyclovir extended release formulations

    Energy Technology Data Exchange (ETDEWEB)

    Barboza, Fernanda M.; Vecchia, Debora D. [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil). Dept. de Ciencias Farmaceuticas. Lab. de Controle de Qualidade; Tagliari, Monika P.; Ferreira, Andrea Granada; Silva, Marcos A.S.; Stulzer, Hellen K., E-mail: hellen.stulzer@gmail.co [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Ciencias Farmaceuticas. Lab. de Controle de Qualidade

    2009-07-01

    Acyclovir (ACV) has been investigated during the past years, mainly due to its antiviral activity. Assessment of possible incompatibility between an active component and different excipients along with the evaluation of thermal stability are crucial parts of a normal study prior to the final formulation setting of a medicine. Thermal analysis studies were used as important and complementary tools during pre-formulation to determine the compatibility of drug excipients with the purpose of developing an acyclovir extended release formulation. Fourier transform infrared spectroscopy and X-ray powder diffraction analyses were also realized. The results showed that ACV only exhibited interaction which could influence the stability of the product in the binary mixtures of ACV/magnesium stearate. (author)

  8. Differential scanning calorimetry as a screening technique in compatibility studies of acyclovir extended release formulations

    International Nuclear Information System (INIS)

    Barboza, Fernanda M.; Vecchia, Debora D.; Tagliari, Monika P.; Ferreira, Andrea Granada; Silva, Marcos A.S.; Stulzer, Hellen K.

    2009-01-01

    Acyclovir (ACV) has been investigated during the past years, mainly due to its antiviral activity. Assessment of possible incompatibility between an active component and different excipients along with the evaluation of thermal stability are crucial parts of a normal study prior to the final formulation setting of a medicine. Thermal analysis studies were used as important and complementary tools during pre-formulation to determine the compatibility of drug excipients with the purpose of developing an acyclovir extended release formulation. Fourier transform infrared spectroscopy and X-ray powder diffraction analyses were also realized. The results showed that ACV only exhibited interaction which could influence the stability of the product in the binary mixtures of ACV/magnesium stearate. (author)

  9. Controlling the optical path length in turbid media using differential path-length spectroscopy: fiber diameter dependence

    NARCIS (Netherlands)

    Kaspers, O. P.; Sterenborg, H. J. C. M.; Amelink, A.

    2008-01-01

    We have characterized the path length for the differential path-length spectroscopy (DPS) fiber optic geometry for a wide range of optical properties and for fiber diameters ranging from 200 mu m to 1000 mu m. Phantom measurements show that the path length is nearly constant for scattering

  10. In vivo quantification of photosensitizer concentration using fluorescence differential path-length spectroscopy : influence of photosensitizer formulation and tissue location

    NARCIS (Netherlands)

    de Visscher, Sebastiaan A. H. J.; Witjes, Max J. H.; Kascakova, Slavka; Sterenborg, Henricus J. C. M.; Robinson, Dominic J.; Roodenburg, Jan L. N.; Amelink, Arjen

    In vivo measurement of photosensitizer concentrations may optimize clinical photodynamic therapy (PDT). Fluorescence differential path-length spectroscopy (FDPS) is a non-invasive optical technique that has been shown to accurately quantify the concentration of Foscan (R) in rat liver. As a next

  11. Mapping Land Cover in the Taita Hills, se Kenya, Using Airborne Laser Scanning and Imaging Spectroscopy Data Fusion

    Science.gov (United States)

    Piiroinen, R.; Heiskanen, J.; Maeda, E.; Hurskainen, P.; Hietanen, J.; Pellikka, P.

    2015-04-01

    The Taita Hills, located in south-eastern Kenya, is one of the world's biodiversity hotspots. Despite the recognized ecological importance of this region, the landscape has been heavily fragmented due to hundreds of years of human activity. Most of the natural vegetation has been converted for agroforestry, croplands and exotic forest plantations, resulting in a very heterogeneous landscape. Given this complex agro-ecological context, characterizing land cover using traditional remote sensing methods is extremely challenging. The objective of this study was to map land cover in a selected area of the Taita Hills using data fusion of airborne laser scanning (ALS) and imaging spectroscopy (IS) data. Land Cover Classification System (LCCS) was used to derive land cover nomenclature, while the height and percentage cover classifiers were used to create objective definitions for the classes. Simultaneous ALS and IS data were acquired over a 10 km x 10 km area in February 2013 of which 1 km x 8 km test site was selected. The ALS data had mean pulse density of 9.6 pulses/m2, while the IS data had spatial resolution of 1 m and spectral resolution of 4.5-5 nm in the 400-1000 nm spectral range. Both IS and ALS data were geometrically co-registered and IS data processed to at-surface reflectance. While IS data is suitable for determining land cover types based on their spectral properties, the advantage of ALS data is the derivation of vegetation structural parameters, such as tree height and crown cover, which are crucial in the LCCS nomenclature. Geographic object-based image analysis (GEOBIA) was used for segmentation and classification at two scales. The benefits of GEOBIA and ALS/IS data fusion for characterizing heterogeneous landscape were assessed, and ALS and IS data were considered complementary. GEOBIA was found useful in implementing the LCCS based classification, which would be difficult to map using pixel-based methods.

  12. Accurate and Rapid Differentiation of Acinetobacter baumannii Strains by Raman Spectroscopy: a Comparative Study.

    Science.gov (United States)

    Ghebremedhin, Meron; Heitkamp, Rae; Yesupriya, Shubha; Clay, Bradford; Crane, Nicole J

    2017-08-01

    In recent years, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has become the standard for routine bacterial species identification due to its rapidity and low costs for consumables compared to those of traditional DNA-based methods. However, it has been observed that strains of some bacterial species, such as Acinetobacter baumannii strains, cannot be reliably identified using mass spectrometry (MS). Raman spectroscopy is a rapid technique, as fast as MALDI-TOF, and has been shown to accurately identify bacterial strains and species. In this study, we compared hierarchical clustering results for MS, genomic, and antimicrobial susceptibility test data to hierarchical clustering results from Raman spectroscopic data for 31 A. baumannii clinical isolates labeled according to their pulsed-field gel electrophoresis data for strain differentiation. In addition to performing hierarchical cluster analysis (HCA), multiple chemometric methods of analysis, including principal-component analysis (PCA) and partial least-squares discriminant analysis (PLSDA), were performed on the MS and Raman spectral data, along with a variety of spectral preprocessing techniques for best discriminative results. Finally, simple HCA algorithms were performed on all of the data sets to explore the relationships between, and natural groupings of, the strains and to compare results for the four data sets. To obtain numerical comparison values of the clustering results, the external cluster evaluation criteria of the Rand index of the HCA dendrograms were calculated. With a Rand index value of 0.88, Raman spectroscopy outperformed the other techniques, including MS (with a Rand index value of 0.58). Copyright © 2017 Ghebremedhin et al.

  13. Spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules.......This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules....

  14. Detection of cervical cancer biomarker patterns in blood plasma and urine by differential scanning calorimetry and mass spectrometry.

    Science.gov (United States)

    Garbett, Nichola C; Merchant, Michael L; Helm, C William; Jenson, Alfred B; Klein, Jon B; Chaires, Jonathan B

    2014-01-01

    Improved methods for the accurate identification of both the presence and severity of cervical intraepithelial neoplasia (CIN) and extent of spread of invasive carcinomas of the cervix (IC) are needed. Differential scanning calorimetry (DSC) has recently been shown to detect specific changes in the thermal behavior of blood plasma proteins in several diseases. This methodology is being explored to provide a complementary approach for screening of cervical disease. The present study evaluated the utility of DSC in differentiating between healthy controls, increasing severity of CIN and early and advanced IC. Significant discrimination was apparent relative to the extent of disease with no clear effect of demographic factors such as age, ethnicity, smoking status and parity. Of most clinical relevance, there was strong differentiation of CIN from healthy controls and IC, and amongst patients with IC between FIGO Stage I and advanced cancer. The observed disease-specific changes in DSC profiles (thermograms) were hypothesized to reflect differential expression of disease biomarkers that subsequently bound to and affected the thermal behavior of the most abundant plasma proteins. The effect of interacting biomarkers can be inferred from the modulation of thermograms but cannot be directly identified by DSC. To investigate the nature of the proposed interactions, mass spectrometry (MS) analyses were employed. Quantitative assessment of the low molecular weight protein fragments of plasma and urine samples revealed a small list of peptides whose abundance was correlated with the extent of cervical disease, with the most striking plasma peptidome data supporting the interactome theory of peptide portioning to abundant plasma proteins. The combined DSC and MS approach in this study was successful in identifying unique biomarker signatures for cervical cancer and demonstrated the utility of DSC plasma profiles as a complementary diagnostic tool to evaluate cervical cancer

  15. Detection of cervical cancer biomarker patterns in blood plasma and urine by differential scanning calorimetry and mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Nichola C Garbett

    Full Text Available Improved methods for the accurate identification of both the presence and severity of cervical intraepithelial neoplasia (CIN and extent of spread of invasive carcinomas of the cervix (IC are needed. Differential scanning calorimetry (DSC has recently been shown to detect specific changes in the thermal behavior of blood plasma proteins in several diseases. This methodology is being explored to provide a complementary approach for screening of cervical disease. The present study evaluated the utility of DSC in differentiating between healthy controls, increasing severity of CIN and early and advanced IC. Significant discrimination was apparent relative to the extent of disease with no clear effect of demographic factors such as age, ethnicity, smoking status and parity. Of most clinical relevance, there was strong differentiation of CIN from healthy controls and IC, and amongst patients with IC between FIGO Stage I and advanced cancer. The observed disease-specific changes in DSC profiles (thermograms were hypothesized to reflect differential expression of disease biomarkers that subsequently bound to and affected the thermal behavior of the most abundant plasma proteins. The effect of interacting biomarkers can be inferred from the modulation of thermograms but cannot be directly identified by DSC. To investigate the nature of the proposed interactions, mass spectrometry (MS analyses were employed. Quantitative assessment of the low molecular weight protein fragments of plasma and urine samples revealed a small list of peptides whose abundance was correlated with the extent of cervical disease, with the most striking plasma peptidome data supporting the interactome theory of peptide portioning to abundant plasma proteins. The combined DSC and MS approach in this study was successful in identifying unique biomarker signatures for cervical cancer and demonstrated the utility of DSC plasma profiles as a complementary diagnostic tool to evaluate

  16. Intensity-Stabilized Fast-Scanned Direct Absorption Spectroscopy Instrumentation Based on a Distributed Feedback Laser with Detection Sensitivity down to 4 × 10−6

    Directory of Open Access Journals (Sweden)

    Gang Zhao

    2016-09-01

    Full Text Available A novel, intensity-stabilized, fast-scanned, direct absorption spectroscopy (IS-FS-DAS instrumentation, based on a distributed feedback (DFB diode laser, is developed. A fiber-coupled polarization rotator and a fiber-coupled polarizer are used to stabilize the intensity of the laser, which significantly reduces its relative intensity noise (RIN. The influence of white noise is reduced by fast scanning over the spectral feature (at 1 kHz, followed by averaging. By combining these two noise-reducing techniques, it is demonstrated that direct absorption spectroscopy (DAS can be swiftly performed down to a limit of detection (LOD (1σ of 4 × 10−6, which opens up a number of new applications.

  17. Differentiation of intracranial tuberculomas and high grade gliomas using proton MR spectroscopy and diffusion MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Juan, E-mail: pengjuan1209@126.com [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China); Ouyang, Yu, E-mail: 1957ouyangyu@sina.com [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China); Fang, Wei-Dong, E-mail: fwd9707@yahoo.com.cn [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China); Luo, Tian-You, E-mail: ltychy@sina.com [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China); Li, Yong-Mei, E-mail: lymzhang70@yahoo.com.cn [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China); Lv, Fa-Jin, E-mail: fajinlv@hotmail.com [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China); Zhang, Zhi-Wei, E-mail: jintianzzw@163.com [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China); Li, Xin-You, E-mail: lixinyou666@163.com [Department of Radiology, the First Affiliated Hospital, Chongqing Medical University, No. 1 Youyi Road, Yuzhong District, Chongqing 400016 (China)

    2012-12-15

    Objective: The purpose of this study was to determine whether proton MR spectroscopy ({sup 1}H MRS) and diffusion-weighted (DW) imaging can be used to differentiate intracranial tuberculomas from high grade gliomas (HGGs). Materials and methods: A total of 41 patients (19 with intracranial tuberculomas and 22 with HGGs) were examined in our study. {sup 1}H MRS and DW imaging were performed at a 1.5T MR scanner before operation or treatment. Concentrations of N-acetylaspartate (NAA), creatine (Cr), choline (Cho), and lipid and lactate (LL) in the contrast-enhancing rim of each lesion were expressed as metabolite ratios and were normalized to the contralateral hemisphere. The apparent diffusion coefficient (ADC) was also calculated. The metabolite ratios and ADC values in the enhancing rim of intracranial tuberculomas and HGGs were compared using the Wilcoxon rank sum test. Diagnostic accuracy was compared using receiver operating characteristic (ROC) analysis. Results: Significant differences were found in the maximum Cho/Cr (P = 0.015), Cho/NAA (P = 0.001) and Cho/Cho-n ratios (P = 0.002), and minimum ADC value (P < 0.001) between the intracranial tuberculomas and HGGs. Diagnostic accuracy was higher by minimum ADC value than maximum Cho/Cr, Cho/NAA and Cho/Cho-n ratios (93.8% versus 75.7%, 80.8% and 78.1%). Conclusion: These results suggest a promising role for {sup 1}H MRS and DW imaging in the differentiation between the intracranial tuberculomas and HGGs.

  18. Optimization of glibenclamide tablet composition through the combined use of differential scanning calorimetry and D-optimal mixture experimental design.

    Science.gov (United States)

    Mura, P; Furlanetto, S; Cirri, M; Maestrelli, F; Marras, A M; Pinzauti, S

    2005-02-07

    A systematic analysis of the influence of different proportions of excipients on the stability of a solid dosage form was carried out. In particular, a d-optimal mixture experimental design was applied for the evaluation of glibenclamide compatibility in tablet formulations, consisting of four classic excipients (natrosol as binding agent, stearic acid as lubricant, sorbitol as diluent and cross-linked polyvinylpyrrolidone as disintegrant). The goal was to find the mixture component proportions which correspond to the optimal drug melting parameters, i.e. its maximum stability, using differential scanning calorimetry (DSC) to quickly obtain information about possible interactions among the formulation components. The absolute value of the difference between the melting peak temperature of pure drug endotherm and that in each analysed mixture and the absolute value of the difference between the enthalpy of the pure glibenclamide melting peak and that of its melting peak in the different analyzed mixtures, were chosen as indexes of the drug-excipient interaction degree.

  19. Characterization of phase change materials for thermal control of photovoltaics using Differential Scanning Calorimetry and Temperature History Method

    International Nuclear Information System (INIS)

    Hasan, A.; McCormack, S.J.; Huang, M.J.; Norton, B.

    2014-01-01

    Highlights: • Five PCM are characterized using tow techniques for PV temperature regulation. • Thermophysical properties of interest are determined and compared with literature. • Determined PCM properties are discussed as criteria for PV temperature regulation. • One PCM identified as potential candidate for PV temperature regulation. - Abstract: Five solid–liquid phase change materials comprising three basic classes, paraffin waxes, salt hydrates and mixtures of fatty acids were thermophysically characterized for thermal regulation applications in photovoltaics. The PCM were investigated using Differential Scanning Calorimetry and Temperature History Method to find their thermophysical properties of interest. The relationship between thermophysical properties of the PCM and their choice as temperature regulators in photovoltaics is discussed in relation to the ambient conditions under which PV systems operate

  20. Adiabatic differential scanning calorimetric study of divalent cation induced DNA - DPPC liposome formulation compacted for gene delivery

    Directory of Open Access Journals (Sweden)

    Erhan Süleymanoglu

    2004-11-01

    Full Text Available Complexes between nucleic acids and phospholipid vesicles have been developed as stable non-viral gene delivery vehicles. Currently employed approach uses positively charged lipid species and a helper zwitterionic lipid, the latter being applied for the stabilization of the whole complex. However, besides problematic steps during their preparation, cationic lipids are toxic for cells. The present work describes some energetic issues pertinent to preparation and use of neutral lipid-DNA self-assemblies, thus avoiding toxicity of lipoplexes. Differential scanning calorimetry data showed stabilization of polynucleotide helix upon its interaction with liposomes in the presence of divalent metal cations. It is thus possible to suggest this self-assembly as an improved formulation for use in gene delivery.

  1. Pengaruh pengawetan kulit ikan buntal (Arothon reticularis terhadap suhu kerut ditinjau melalui analisis differential scanning calorimeter (DSC

    Directory of Open Access Journals (Sweden)

    RLM. Satrio Ari Wibowo

    2015-12-01

    Full Text Available The aim of this study was to determine the effect of the skin preservation type against shrinkage temperature of leather. The material used in this study was the skin of pufferfish (Arothon reticularis that have been preserved by salting, formaldehyde and pickling and also raw skin as a reference. The method used to measure the shrinkage temperature was thermal analysis using Differential Scanning Calorimeter (DSC that operated from 4°C up to 440°C with nitrogen stream. DSC measurement results showed that shrinkage temperature of puffer fish preserved with formaldehyde was higher than salting and pickling, which is 63.64°C; 47.95°C; 57.37oC respectively. The advantage of using formaldehyde compared to others preservation technique was not only can protect the skin from damage by microorganisms, but also can create a bond with the collagen .

  2. NO2 measurements in Hong Kong using LED based long path differential optical absorption spectroscopy

    Directory of Open Access Journals (Sweden)

    M. O. Wenig

    2012-05-01

    Full Text Available In this study we present the first long term measurements of atmospheric nitrogen dioxide (NO2 using a LED based Long Path Differential Optical Absorption Spectroscopy (LP-DOAS instrument. This instrument is measuring continuously in Hong Kong since December 2009, first in a setup with a 550 m absorption path and then with a 3820 m path at about 30 m to 50 m above street level. The instrument is using a high power blue light LED with peak intensity at 450 nm coupled into the telescope using a Y-fibre bundle. The LP-DOAS instrument measures NO2 levels in the Kowloon Tong and Mongkok district of Hong Kong and we compare the measurement results to mixing ratios reported by monitoring stations operated by the Hong Kong Environmental Protection Department in that area. Hourly averages of coinciding measurements are in reasonable agreement (R = 0.74. Furthermore, we used the long-term data set to validate the Ozone Monitoring Instrument (OMI NO2 data product. Monthly averaged LP-DOAS and OMI measurements correlate well (R = 0.84 when comparing the data for the OMI overpass time. We analyzed weekly patterns in both data sets and found that the LP-DOAS detects a clear weekly cycle with a reduction on weekends during rush hour peaks, whereas OMI is not able to observe this weekly cycle due to its fix overpass time (13:30–14:30 LT – local time.

  3. Continuous correction of differential path length factor in near-infrared spectroscopy

    Science.gov (United States)

    Talukdar, Tanveer; Moore, Jason H.; Diamond, Solomon G.

    2013-05-01

    In continuous-wave near-infrared spectroscopy (CW-NIRS), changes in the concentration of oxyhemoglobin and deoxyhemoglobin can be calculated by solving a set of linear equations from the modified Beer-Lambert Law. Cross-talk error in the calculated hemodynamics can arise from inaccurate knowledge of the wavelength-dependent differential path length factor (DPF). We apply the extended Kalman filter (EKF) with a dynamical systems model to calculate relative concentration changes in oxy- and deoxyhemoglobin while simultaneously estimating relative changes in DPF. Results from simulated and experimental CW-NIRS data are compared with results from a weighted least squares (WLSQ) method. The EKF method was found to effectively correct for artificially introduced errors in DPF and to reduce the cross-talk error in simulation. With experimental CW-NIRS data, the hemodynamic estimates from EKF differ significantly from the WLSQ (p<0.001). The cross-correlations among residuals at different wavelengths were found to be significantly reduced by the EKF method compared to WLSQ in three physiologically relevant spectral bands 0.04 to 0.15 Hz, 0.15 to 0.4 Hz and 0.4 to 2.0 Hz (p<0.001). This observed reduction in residual cross-correlation is consistent with reduced cross-talk error in the hemodynamic estimates from the proposed EKF method.

  4. Design of differential optical absorption spectroscopy long-path telescopes based on fiber optics.

    Science.gov (United States)

    Merten, André; Tschritter, Jens; Platt, Ulrich

    2011-02-10

    We present a new design principle of telescopes for use in the spectral investigation of the atmosphere and the detection of atmospheric trace gases with the long-path differential optical absorption spectroscopy (DOAS) technique. A combination of emitting and receiving fibers in a single bundle replaces the commonly used coaxial-Newton-type combination of receiving and transmitting telescope. This very simplified setup offers a higher light throughput and simpler adjustment and allows smaller instruments, which are easier to handle and more portable. The higher transmittance was verified by ray-tracing calculations, which result in a theoretical factor threefold improvement in signal intensity compared with the old setup. In practice, due to the easier alignment and higher stability, up to factor of 10 higher signal intensities were found. In addition, the use of a fiber optic light source provides a better spectral characterization of the light source, which results in a lower detection limit for trace gases studied with this instrument. This new design will greatly enhance the usability and the range of applications of active DOAS instruments.

  5. Evaluation of accidental coincidences for time-differential Moessbauer-spectroscopy

    International Nuclear Information System (INIS)

    Alflen, M.; Meyer, W.

    1995-01-01

    The accidental coincidences of a measuring system based on time-to-amplitude conversion are considered in some detail for the case of low starting and high stopping rates. Two types of accidental coincidences are distinguished, those carrying time information and those without time information. Neglecting any deadtime effects of the detectors, analytical expressions for the calculation of the time distribution of the random coincidences are evaluated. The analytical expressions have been confirmed by Monte Carlo simulations. The procedure is applied to time-differential Moessbauer spectroscopy in order to extract the time spectra of true coincidences. The measured spectrum in a time channel turns out to be a superposition of the true spectrum (true coincidences), a time integral spectrum (random coincidences), and a weighted superposition of true spectra of other time channels (random but time carrying information). A measurement with a single line 57 Co/Rh-source and single line K[Fe(CN) 6 ].3H 2 O-absorber with stopping rates of 1 MBq shows agreement between the theoretical time-filtered spectra and the corrected measured spectra of true coincidences. ((orig.))

  6. Forensic Hair Differentiation Using Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopy.

    Science.gov (United States)

    Manheim, Jeremy; Doty, Kyle C; McLaughlin, Gregory; Lednev, Igor K

    2016-07-01

    Hair and fibers are common forms of trace evidence found at crime scenes. The current methodology of microscopic examination of potential hair evidence is absent of statistical measures of performance, and examiner results for identification can be subjective. Here, attenuated total reflection (ATR) Fourier transform-infrared (FT-IR) spectroscopy was used to analyze synthetic fibers and natural hairs of human, cat, and dog origin. Chemometric analysis was used to differentiate hair spectra from the three different species, and to predict unknown hairs to their proper species class, with a high degree of certainty. A species-specific partial least squares discriminant analysis (PLSDA) model was constructed to discriminate human hair from cat and dog hairs. This model was successful in distinguishing between the three classes and, more importantly, all human samples were correctly predicted as human. An external validation resulted in zero false positive and false negative assignments for the human class. From a forensic perspective, this technique would be complementary to microscopic hair examination, and in no way replace it. As such, this methodology is able to provide a statistical measure of confidence to the identification of a sample of human, cat, and dog hair, which was called for in the 2009 National Academy of Sciences report. More importantly, this approach is non-destructive, rapid, can provide reliable results, and requires no sample preparation, making it of ample importance to the field of forensic science. © The Author(s) 2016.

  7. Monosodium glutamate in its anhydrous and monohydrate form: Differentiation by Raman spectroscopies and density functional calculations

    Science.gov (United States)

    Peica, N.; Lehene, C.; Leopold, N.; Schlücker, S.; Kiefer, W.

    2007-03-01

    Monosodium glutamate (MSG), a common flavor enhancer, is detected in aqueous solutions by Raman and surface-enhanced Raman (SERS) spectroscopies at the micromolar level. The presence of different species, such as protonated and unprotonated MSG, is demonstrated by concentration and pH dependent Raman and SERS experiments. In particular, the symmetric bending modes of the amino group and the stretching modes of the carboxy moiety are employed as marker bands. The protonation of the NH 2 group at acidic pH values, for example, is detected in the Raman spectra. From the measured SERS spectra, a strong chemical interaction of MSG with the colloidal particles is deduced and a geometry of MSG adsorbed on the silver surface is proposed. In order to assign the observed Raman bands, calculations employing density functional theory (DFT) were performed. The calculated geometries, harmonic vibrational wavenumbers and Raman scattering activities for both MSG forms are in good agreement with experimental data. The set of theoretical data enables a complete vibrational assignment of the experimentally detected Raman spectra and the differentiation between the anhydrous and monohydrate forms of MSG.

  8. Noninvasive monitoring of glucose concentration using differential absorption low-coherence interferometry based on rapid scanning optical delay line

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Yong; Zeng Nan; He Yonghong, E-mail: heyh@sz.tsinghua.edu.cn [Laboratory of Optical Imaging and Sensing, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055 (China)

    2011-01-01

    A non-invasive method of detecting glucose concentration using differential absorption low-coherence interferometry (DALCI) based on rapid scanning optical delay line is presented. Two light sources, one centered within (1625 nm) a glucose absorption band, while the other outside (1310 nm) the glucose absorption band, are used in the experiment. The low-coherence interferometry (LCI) is employed to obtain the signals back-reflecting from the iris which carries the messages of material concentration in anterior chamber. Using rapid scanning optical delay line (RSOD) as the reference arm, we can detect the signals in a very short time. Therefore the glucose concentration can be monitored in real-time, which is very important for the detection in vivo. In our experiments, the cornea and aqueous humor can be treated as nearly non-scattering substance. The difference in the absorption coefficient is much larger than the difference in the scattering coefficient, so the influence of scattering can be neglected. By subtracting the algorithmic low-coherence interference signals of the two wavelengths, the absorption coefficient can be calculated which is proportional to glucose concentration. To reduce the speckle noise, a 30 variation of signals were used before the final calculation of the glucose concentration. The improvements of our experiment are also discussed in the article. The method has a potential application for noninvasive detection of glucose concentration in vivo and in real-time.

  9. Structural studies of agar-gelatin complex coacervates by small angle neutron scattering, rheology and differential scanning calorimetry.

    Science.gov (United States)

    Singh, S Santinath; Aswal, V K; Bohidar, H B

    2007-08-01

    Agar-gelatin complex coacervates are studied by small angle neutron scattering (SANS), rheology (in both flow and temperature scan modes) and differential scanning calorimetry (DSC) in order to probe the microscopic structure of this dense protein-polysaccharide-rich phase. DSC and isochronal temperature sweep (rheology) experiments yielded a characteristic temperature at approximately 35+/-2 degrees C. Rheology data revealed a second characteristic temperature at approximately 75+/-5 degrees C which was absent in DSC thermograms. In the flow mode, shear viscosity (eta) was found to scale with (Carreau model) applied shear rate (gamma ) as: eta(gamma ) approximately (gamma )(-k) with k=1.2+/-0.2 indicating non-Newtonian and shear-thinning features independent of ionic strength. The static structure factor S(q) deduced from SANS data in the low wave vector (0.018 A(-1)high-q region, called the Ornstein-Zernike regime, S(q) approximately 1/(1+xi(2)q(2)) gave correlation length xi approximately 12+/-2A. The results taken together imply the existence of a weakly interconnected and heterogeneous network structure inside the coacervate phase. Structural features of this material are compared with those of agar and gelatin gel, and gelatin coacervate.

  10. Value of 201Tl imaging in predicting therapeutic 131I uptake in patients with thyroglobulin-positive but 131I scan-negative differentiated thyroid carcinoma

    International Nuclear Information System (INIS)

    Conlu, R.A.O.; Obaldo, J.M.

    2004-01-01

    Background: Serum thyroglobulin assay and 131Iodine (1311) whole body scan are considered complementary in detecting malignant thyroid tissue or metastases. A large number of patients, however, are encountered presenting with scan-negative, thyroglobulin-positive differentiated thyroid carcinoma posing a dilemma in therapeutic management. One of the first alternative scanning agents to be employed is 201Thallium (201Tl). Recent studies have demonstrated its usefulness in identifying lesions that are not visualized with traditional 131I whole body scan. It is not clear, however, whether 201Tl scan helps in the decision-making for subsequent 131I therapy. This study was conducted to determine if 201Tl scan can predict therapeutic 131I uptake and to define the clinical role of 201Tl scanning in these patients. Methods and results: A total of 12 patients (20-63 y/o), 5 males and 7 females, underwent surgery for differentiated thyroid cancer and all had serum thyroglobulin values above 10 ng/ml and normal TPO autoantibodies. Pre-therapy 131I scan using 111 MBq (3mCi) of 131I were obtained. As required for inclusion, all patients had negative pre-therapy scan and negative TPO autoantibody results and underwent 20lTl scanning within 3 weeks. All patients were given 131I therapy (3.7-5.5 GBq or 100-150 mCi) between one to two months after 201Tl scanning. Within a week after therapy, all patients underwent whole body 1311 scanning. 201Tl imaging demonstrated thyroid remnants in 9 out of 12 patients having positive 201Tl scan but negative pre-therapy 1311 scan. However, only 2 of the positive 201Tl scans showed 131I uptake post-therapy (positive predictive value of 20%). None of the subjects presented with a negative 201Tl scan and a positive post-therapy 131I scan. Conclusion: Our study suggests that evidence of remnants or metastases on 201Tl scanning may be an inappropriate basis for the decision to proceed with 131I therapy. The role of 20lTl imaging in this subset of

  11. Differential laser-induced perturbation Raman spectroscopy: a comparison with Raman spectroscopy for analysis and classification of amino acids and dipeptides.

    Science.gov (United States)

    Oztekin, Erman K; Smith, Sarah E; Hahn, David W

    2015-04-01

    Differential-laser induced perturbation spectroscopy (DLIPS) is a new spectral analysis technique for classification and identification, with key potential applications for analysis of complex biomolecular systems. DLIPS takes advantage of the complex ultraviolet (UV) laser–material interactions based on difference spectroscopy by coupling low intensity UV laser perturbation with a traditional spectroscopy probe. Here, we quantify the DLIPS performance using a Raman scattering probe in classification of basic constituents of collagenous tissues, namely, the amino acids glycine, L-proline, and L-alanine, and the dipeptides glycine–glycine, glycine–alanine and glycine–proline and compare the performance to a traditional Raman spectroscopy probe via several multivariate analyses. We find that the DLIPS approach yields an ~40% improvement in discrimination among these tissue building blocks. The effects of the 193-nm perturbation laser are further examined by assessing the photodestruction of targeted material molecular bonds. The DLIPS method with a Raman probe holds promise for future tissue diagnosis, either as a stand-alone technique or as part of an orthogonal biosensing scheme.

  12. spectroscopy

    African Journals Online (AJOL)

    Aghomotsegin

    2015-10-14

    Oct 14, 2015 ... Full Length Research Paper. Determination of lactic acid bacteria in Kaşar cheese and identification by Fourier transform infrared (FTIR) spectroscopy. İlkay Turhan1* and Zübeyde Öner2. 1Department of Nutrition and Dietetic, School of Health Sciences, T.C.Istanbul Arel University, 34537 Buyukcekmece /.

  13. Cavity ring-down spectroscopy (CRDS) system for measuring atmospheric mercury using differential absorption

    Science.gov (United States)

    Pierce, A.; Obrist, D.; Moosmuller, H.; Moore, C.

    2012-04-01

    Atmospheric elemental mercury (Hg0) is a globally pervasive element that can be transported and deposited to remote ecosystems where it poses — particularly in its methylated form — harm to many organisms including humans. Current techniques for measurement of atmospheric Hg0 require several liters of sample air and several minutes for each analysis. Fast-response (i.e., 1 second or faster) measurements would improve our ability to understand and track chemical cycling of mercury in the atmosphere, including high frequency Hg0 fluctuations, sources and sinks, and chemical transformation processes. We present theory, design, challenges, and current results of our new prototype sensor based on cavity ring-down spectroscopy (CRDS) for fast-response measurement of Hg0 mass concentrations. CRDS is a direct absorption technique that implements path-lengths of multiple kilometers in a compact absorption cell using high-reflectivity mirrors, thereby improving sensitivity and reducing sample volume compared to conventional absorption spectroscopy. Our sensor includes a frequency-doubled, dye-laser emitting laser pulses tunable from 215 to 280 nm, pumped by a Q-switched, frequency tripled Nd:YAG laser with a pulse repetition rate of 50 Hz. We present how we successfully perform automated wavelength locking and stabilization of the laser to the peak Hg0 absorption line at 253.65 nm using an external isotopically-enriched mercury (202Hg0) cell. An emphasis of this presentation will be on the implementation of differential absorption measurement whereby measurements are alternated between the peak Hg0 absorption wavelength and a nearby wavelength "off" the absorption line. This can be achieved using a piezo electric tuning element that allows for pulse-by-pulse tuning and detuning of the laser "online" and "offline" of the Hg absorption line, and thereby allows for continuous correction of baseline extinction losses. Unexpected challenges with this approach included

  14. Ochre-differentiation through micro-Raman and micro-FTIR spectroscopies: application on wall paintings at Meteora and Mount Athos, Greece

    Science.gov (United States)

    Bikiaris, D.; Daniilia, Sister; Sotiropoulou, S.; Katsimbiri, O.; Pavlidou, E.; Moutsatsou, A. P.; Chryssoulakis, Y.

    2000-01-01

    The most widely-used inorganic pigments of Byzantine and post-Byzantine hagiography are earth pigments called ochres such as, red and yellow ochres, limonite, goethite, raw and burnt sienna, caput mortuum and hematite. The present experimental work proposes a technique of differentiation that allows one to distinguish among all the different kinds of iron oxides, thereby providing a better understanding of the painting technique used on portable icons and wall paintings. The ratios between the main spectroscopic peaks, attributable to the major components usually present in ochres, were calculated and compared, one against the another, from the spectra obtained through micro-Raman spectroscopy. Elementary composition is also revealed through a scanning electron microscopy (SEM) analysis. The possibility for detailed study on a particular Byzantine ochre palette can thus be performed based on the small differences in its nature and composition. These differences can first be observed and then measured among all of the natural earth pigments, through μRaman and μFTIR spectroscopies.

  15. Usefulness of 99mTc-Sestamibi whole body scan in the follow-up of differentiated thyroid cancer

    International Nuclear Information System (INIS)

    Pastore, Francisco A.; Fernandez, C.; Rios, V.; Funes Lorea, A; Volpe, B.; Lopez, S.

    2006-01-01

    Although radioiodine is and had been the more common used radioisotope in the follow-up of differentiated thyroid cancer (DTC), other radioisotopes, such as 99m Tc sestamibi (MIBI), had been incorporated as auxiliary methods. Our objective was to assess the diagnostic usefulness of MIBI in the long term follow-up of DTC. Thirty-two patients (26 (81%) female), mean age 45 ± 12.6 years, 2 with follicular carcinoma, and 30 with papillary carcinoma, were prospectively studied with MIBI. Mean time of follow-up from thyroidectomy to MIBI was 4.6 ± 4.9 years. (range, 7 months to 22 years). Sensitivity (Sens), specificity (Spec), positive predictive value (PPV), negative predictive value (NPV), and accuracy (A) was evaluated. We assessed agreement for MIBI and 131 I, by means of percent agreement and Cohen's kappa (k) statistic. The gold standard method to indicate persistent disease was serum thyroglobulin (Tg) measurement by ICMA, with cut-off level of = 2 ng/ml 'off T4', and > 0.2 ng/ml 'on T4'. In 3 patients with positive anti-Tg antibodies, 131 I scan and other auxiliary methods (Ultrasound, CT scan) were considered as gold standard. For MIBI the values of Sens, Spec, PPV, NPP, and A were 29% (26-32), 93% (89-96), 83% (74-91), 53% (51-55), and 59% (57-61), respectively. For 131 I were 31% (27-34), 100% (96-100), 100% (90-100), 56% (53-58), and 63% (61-65), respectively. The percent agreement between both radiopharmaceuticals was 76.6%, and k was 0.2 (-0.19 -0.63). Similar statistical indicators for MIBI and 131 I warrant the use of the former as alternative method. At the same time, a fair agreement between both radiopharmaceuticals demonstrates the additive information offered by MIBI in the follow-up of DTC. (author) [es

  16. Functional imaging in differentiating bronchial masses: an initial experience with a combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan.

    Science.gov (United States)

    Kumar, Arvind; Jindal, Tarun; Dutta, Roman; Kumar, Rakesh

    2009-10-01

    To evaluate the role of combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan in differentiating bronchial tumors observed in contrast enhanced computed tomography scan of chest. Prospective observational study. Place of study: All India Institute of Medical Sciences, New Delhi, India. 7 patients with bronchial mass detected in computed tomography scan of the chest were included in this study. All patients underwent (18)F-FDG PET-CT scan, (68)Ga DOTA-TOC PET-CT scan and fiberoptic bronchoscope guided biopsy followed by definitive surgical excision. The results of functional imaging studies were analyzed and the results are correlated with the final histopathology of the tumor. Histopathological examination of 7 bronchial masses revealed carcinoid tumors (2 typical, 1 atypical), inflammatory myofibroblastic tumor (1), mucoepidermoid carcinoma (1), hamartoma (1), and synovial cell sarcoma (1). The typical carcinoids had mild (18)F-FDG uptake and high (68)Ga DOTA-TOC uptake. Atypical carcinoid had moderate uptake of (18)F-FDG and high (68)Ga DOTA-TOC uptake. Inflammatory myofibroblastic tumor showed high uptake of (18)F-FDG and no uptake of (68)Ga DOTA-TOC. Mucoepidermoid carcinoma showed mild (18)F-FDG uptake and no (68)Ga DOTA-TOC uptake. Hamartoma showed no uptake on either scans. Synovial cell sarcoma showed moderate (18)F-FDG uptake and mild focal (68)Ga DOTA-TOC uptake. This initial experience with the combined use of (18)F-FDG and (68)Ga DOTA-TOC PET-CT scan reveals different uptake patterns in various bronchial tumors. Bronchoscopic biopsy will continue to be the gold standard; however, the interesting observations made in this study merits further evaluation of the utility of the combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan in larger number of patients with bronchial masses.

  17. Scanning tunneling microscopy and spectroscopy on GaN and InGaN surfaces; Rastertunnelmikroskopie und -spektroskopie an GaN- und InGaN-Oberflaechen

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, David

    2009-12-02

    Optelectronic devices based on gallium nitride (GaN) and indium gallium nitride (InGaN) are in the focus of research since more than 20 years and still have great potential for optical applications. In the first part of this work non-polar surfaces of GaN are investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and scanning tunneling microscopy (STM). In SEM and AFM, the (1 anti 100)- and especially the (anti 2110)-plane are quite corrugated. For the first time, the (anti 2110)-plane of GaN is atomically resolved in STM. In the second part InGaN quantum dot layers are investigated by X-ray photoelectron spectroscopy (XPS), scanning tunneling spectroscopy (STS) and STM. The STMmeasurements show the dependency of surface morphology on growth conditions in the metalorganic vapour phase epitaxy (MOVPE). Nucleation, a new MOVPE-strategy, is based on phase separations on surfaces. It is shown that locally varying density of states and bandgaps can be detected by STS, that means bandgap histograms and 2D-bandgap-mapping. (orig.)

  18. Comments on the interpretation of differential scanning calorimetry results for thermoelastic martensitic transformations: Athermal versus thermally activated kinetics

    International Nuclear Information System (INIS)

    Morris, A.; Lipe, T.

    1996-01-01

    In a previous article Van Humbeeck and Planes have made a number of criticisms of the authors' recent paper concerning the interpretation of the results obtained by Differential Scanning Calorimetry (DSC) from the Martensitic Transformation of Cu-Al-Ni-Mn-B alloys. Although the martensitic transformation of these shape memory alloys is generally classified as athermal, it has been confirmed that the capacity of the alloys to undergo a more complete thermoelastic transformation (i.e. better reversibility of the transformation) increased with the Mn content. This behavior has been explained by interpreting the DSC results obtained during thermal cycling in terms of a thermally activated mechanism controlling the direct and reverse transformations. When the heating rate increases during the reverse transformation the DSC curves shift towards higher temperatures while they shift towards the lower temperatures when the cooling rate was increased during the direct transformation. Since the starting transformation temperatures (As, Ms) do not shift, Van Humbeeck and Planes state that there is no real peak shift and assume that the DCS experiments were carried out without taking into account the thermal lag effect between sample and cell. On the following line they deduce a time constant, τ, of 60 seconds because the peak maximum shifts. In fact the assumption made by Van Humbeeck and Planes is false

  19. Thermal decomposition study of monovarietal extra virgin olive oil by simultaneous thermogravimetry/differential scanning calorimetry: relation with chemical composition.

    Science.gov (United States)

    Vecchio, Stefano; Cerretani, Lorenzo; Bendini, Alessandra; Chiavaro, Emma

    2009-06-10

    Thermal decomposition of 12 monovarietal extra virgin olive oils from different geographical origins (eight from Italy, two from Spain, and the others from Tunisia) was evaluated by simultaneous thermogravimetry (TG) and differential scanning calorimetry (DSC) analyses. All extra virgin olive oils showed a complex multistep decomposition pattern with the first step that exhibited a quite different profile among samples. Thermal properties of the two peaks obtained by the deconvolution of the first step of decomposition by DSC were related to the chemical composition of the samples (triacylglycerols, fatty acids, total phenols and antioxidant activity). Onset temperatures of the thermal decomposition transition and T(p) values of both deconvoluted peaks as well as the sum of enthalpy were found to exhibit statistically significant correlations with chemical components of the samples, in particular palmitic and oleic acids and related triacylglycerols. Activation energy values of the second deconvoluted peak obtained by the application of kinetic procedure to the first step of decomposition were also found to be highly statistically correlated to the chemical composition, and a stability scale among samples was proposed on the basis of its values.

  20. Weak interactions in clobazam–lactose mixtures examined by differential scanning calorimetry: Comparison with the captopril–lactose system

    International Nuclear Information System (INIS)

    Toscani, S.; Cornevin, L.; Burgot, G.

    2012-01-01

    Highlights: ► Thermodynamic and kinetic parameters of weak interactions in binary systems by DSC. ► Energy-barrier decrease for lactose dehydration induced by clobazam. ► Recrystallisation of metastable liquid clobazam induced by anhydrous alpha lactose. ► Decrease of lactose dehydration temperature in binary mixtures with captopril. ► Increase of lactose dehydration enthalpy in binary mixtures with captopril. - Abstract: The thermal behaviour of binary mixtures of two drugs (clobazam and captopril, respectively) and a pharmaceutical excipient (lactose monohydrate) was measured with differential scanning calorimetry to determine thermodynamic and kinetic parameters (dehydration and melting enthalpies and dehydration and glass-transition activation energies) which might be affected by intermolecular interactions. A kinetic study showed that lactose dehydration is not a single-step conversion and that clobazam contributed to reduce the energy barrier for the bulk dehydration of the excipient. On the other hand, the physical interactions between metastable liquid clobazam and crystalline anhydrous α-lactose obtained from monohydrate dehydration gave rise to the recrystallisation of clobazam. In the captopril–lactose system, the liquid captopril influenced the lactose dehydration: a sharp increase of the dehydration enthalpy and a concurrent reduction of the dehydration temperature were observed. Finally, it turned out that solid-phase transitions were enhanced by the contact with a liquid phase.

  1. Weak interactions in clobazam-lactose mixtures examined by differential scanning calorimetry: Comparison with the captopril-lactose system

    Energy Technology Data Exchange (ETDEWEB)

    Toscani, S. [Departement de Chimie - UMR 6226, Faculte des Sciences, Universite de Rennes 1, Batiment 10B, 263 avenue du General Leclerc, F-35042 Rennes Cedex (France); Cornevin, L. [Universite de Rennes 1, Faculte de Pharmacie, 2 Avenue Leon Bernard, F-35043 Rennes Cedex (France); Burgot, G., E-mail: Gwenola.burgot@univ-rennes1.fr [Universite de Rennes 1, Faculte de Pharmacie, Laboratoire de Chimie Analytique, EA 1274 ' Mouvement, sports, sante' , 2 Avenue Leon Bernard, F-35043 Rennes Cedex (France); CHGR Rennes, Pole Medico-Technique Pharmacie, F-35703 Rennes Cedex (France)

    2012-09-10

    Highlights: Black-Right-Pointing-Pointer Thermodynamic and kinetic parameters of weak interactions in binary systems by DSC. Black-Right-Pointing-Pointer Energy-barrier decrease for lactose dehydration induced by clobazam. Black-Right-Pointing-Pointer Recrystallisation of metastable liquid clobazam induced by anhydrous alpha lactose. Black-Right-Pointing-Pointer Decrease of lactose dehydration temperature in binary mixtures with captopril. Black-Right-Pointing-Pointer Increase of lactose dehydration enthalpy in binary mixtures with captopril. - Abstract: The thermal behaviour of binary mixtures of two drugs (clobazam and captopril, respectively) and a pharmaceutical excipient (lactose monohydrate) was measured with differential scanning calorimetry to determine thermodynamic and kinetic parameters (dehydration and melting enthalpies and dehydration and glass-transition activation energies) which might be affected by intermolecular interactions. A kinetic study showed that lactose dehydration is not a single-step conversion and that clobazam contributed to reduce the energy barrier for the bulk dehydration of the excipient. On the other hand, the physical interactions between metastable liquid clobazam and crystalline anhydrous {alpha}-lactose obtained from monohydrate dehydration gave rise to the recrystallisation of clobazam. In the captopril-lactose system, the liquid captopril influenced the lactose dehydration: a sharp increase of the dehydration enthalpy and a concurrent reduction of the dehydration temperature were observed. Finally, it turned out that solid-phase transitions were enhanced by the contact with a liquid phase.

  2. Effect of polyglycerol esters additive on palm oil crystallization using focused beam reflectance measurement and differential scanning calorimetry.

    Science.gov (United States)

    Saw, M H; Hishamuddin, E; Chong, C L; Yeoh, C B; Lim, W H

    2017-01-01

    The effect of 0.1-0.7% (w/w) of polyglycerol esters (PGEmix-8) on palm oil crystallization was studied using focused beam reflectance measurement (FBRM) to analyze the in-line changes of crystal size distribution during the crystallization. FBRM results show that 0.1-0.5% (w/w) of PGEmix-8 did not significantly affect nucleation but slightly retarded crystal growth. The use of 0.7% (w/w) additive showed greater heterogeneous nucleation compared to those with lower dosages of additive. Crystal growth was also greatly reduced when using 0.7% (w/w) dosage. The morphological study indicated that the palm oil crystals were smaller and more even in size than when more additive was added. Isothermal crystallization studies using differential scanning calorimetry (DSC) showed increased inhibitory effects on palm oil crystal growth with increasing concentration of PGEmix-8. These results imply that PGEmix-8 is a nucleation enhancing and crystal growth retarding additive in palm oil crystallization at 0.7% (w/w) dosage. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  3. Cholesterol affects the interaction between an ionic liquid and phospholipid vesicles. A study by differential scanning calorimetry and nanoplasmonic sensing.

    Science.gov (United States)

    Russo, Giacomo; Witos, Joanna; Rantamäki, Antti H; Wiedmer, Susanne K

    2017-12-01

    The present work aims at studying the interactions between cholesterol-rich phosphatidylcholine-based lipid vesicles and trioctylmethylphosphonium acetate ([P 8881 ][OAc]), a biomass dissolving ionic liquid (IL). The effect of cholesterol was assayed by using differential scanning calorimetry (DSC) and nanoplasmonic sensing (NPS) measurement techniques. Cholesterol-enriched dipalmitoyl-phosphatidylcholine vesicles were exposed to different concentrations of the IL, and the derived membrane perturbation was monitored by DSC. The calorimetric data could suggest that the binding and infiltration of the IL are delayed in the vesicles containing cholesterol. To clarify our findings, NPS was applied to quantitatively follow the resistance of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine incorporating 0, 10, and 50mol% of cholesterol toward the IL exposure over time. The membrane perturbation induced by different concentrations of IL was found to be a concentration dependent process on cholesterol-free lipid vesicles. Moreover, our results showed that lipid depletion in cholesterol-enriched lipid vesicles is inversely proportional to the increasing amount of cholesterol in the vesicles. These findings support that cholesterol-rich lipid bilayers are less susceptible toward membrane disrupting agents as compared to membranes that do not incorporate any sterols. This probably occurs because cholesterol tightens the phospholipid acyl chain packing of the plasma membranes, increasing their resistance and reducing their permeability. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Raman scattering boson peak and differential scanning calorimetry studies of the glass transition in tellurium-zinc oxide glasses

    International Nuclear Information System (INIS)

    Stavrou, E; Tsiantos, C; Tsopouridou, R D; Kripotou, S; Kontos, A G; Raptis, C; Capoen, B; Bouazaoui, M; Turrell, S; Khatir, S

    2010-01-01

    Raman scattering and differential scanning calorimetry (DSC) measurements have been carried out on four mixed tellurium-zinc oxide (TeO 2 ) 1-x (ZnO) x (x = 0.1, 0.2, 0.3, 0.4) glasses under variable temperature, with particular attention being given to the respective glass transition region. From the DSC measurements, the glass transition temperature T g has been determined for each glass, showing a monotonous decrease of T g with increasing ZnO content. The Raman study is focused on the low-frequency band of the glasses, the so-called boson peak (BP), whose frequency undergoes an abrupt decrease at a temperature T d very close to the respective T g values obtained by DSC. These results show that the BP is highly sensitive to dynamical effects over the glass transition and provides a means for an equally reliable (to DSC) determination of T g in tellurite glasses and other network glasses. The discontinuous temperature dependence of the BP frequency at the glass transition, along with the absence of such a behaviour by the high-frequency Raman bands (due to local atomic vibrations), indicates that marked changes of the medium range order (MRO) occur at T g and confirms the correlation between the BP and the MRO of glasses.

  5. Raman scattering boson peak and differential scanning calorimetry studies of the glass transition in tellurium-zinc oxide glasses.

    Science.gov (United States)

    Stavrou, E; Tsiantos, C; Tsopouridou, R D; Kripotou, S; Kontos, A G; Raptis, C; Capoen, B; Bouazaoui, M; Turrell, S; Khatir, S

    2010-05-19

    Raman scattering and differential scanning calorimetry (DSC) measurements have been carried out on four mixed tellurium-zinc oxide (TeO(2))(1 - x)(ZnO)(x) (x = 0.1, 0.2, 0.3, 0.4) glasses under variable temperature, with particular attention being given to the respective glass transition region. From the DSC measurements, the glass transition temperature T(g) has been determined for each glass, showing a monotonous decrease of T(g) with increasing ZnO content. The Raman study is focused on the low-frequency band of the glasses, the so-called boson peak (BP), whose frequency undergoes an abrupt decrease at a temperature T(d) very close to the respective T(g) values obtained by DSC. These results show that the BP is highly sensitive to dynamical effects over the glass transition and provides a means for an equally reliable (to DSC) determination of T(g) in tellurite glasses and other network glasses. The discontinuous temperature dependence of the BP frequency at the glass transition, along with the absence of such a behaviour by the high-frequency Raman bands (due to local atomic vibrations), indicates that marked changes of the medium range order (MRO) occur at T(g) and confirms the correlation between the BP and the MRO of glasses.

  6. Microstructure characterization of a food-grade U-type microemulsion system by differential scanning calorimetry and electrical conductivity techniques.

    Science.gov (United States)

    Zhang, Hui; Taxipalati, Maierhaba; Que, Fei; Feng, Fengqin

    2013-12-01

    The microstructure transitions of a food-grade U-type microemulsion system containing glycerol monolaurate and propionic acid at a 1:1 mass ratio as oil phase and Tween 80 as surfactant were investigated along a water dilution line at a ratio of 80:20 mass% surfactant/oil phase, based on a previously studied phase diagram. From the water thermal behaviours detected by differential scanning calorimetry, three structural regions are identified along the dilution line. In the first region, all water molecules are confined to the water core of the reverse micelles, leading to the formation of w/o microemulsion. As the water content increases, the water gains mobility, transforms into bicontinuous in the second region, and finally the microemulsion become o/w in the third region. The thermal transition points coincide with the structural phase transitions by electrical conductivity measurements, indicating that the structural transitions occur at 35 and 65 mass% of water along the dilution line. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Effects of particle size on the desorption kinetics of water from Beulah-Zap lignite coal: Differential scanning calorimetry results

    Energy Technology Data Exchange (ETDEWEB)

    Dang, Yuhong; Malhotra, V.M. [Southern Illinois Univ., Carbondale, IL (United States); Vorres, K.S. [Argonne National Lab., IL (United States). Chemistry Div.

    1996-03-01

    The drying kinetics of water from three particle-sized Beulah-Zap lignite coal samples were probed using the differential scanning calorimetry technique at 295 < T < 480 K. The measurements undertaken under flowing N{sub 2} gas environment indicate that water is lost from this coal by two independent but simultaneously operative kinetic mechanisms. Our results suggest that the unimolecular decay kinetics are obeyed by those water molecules which are near the mouths of large pores and/or surround the coal particles. Most of the water, about 80% of the water lost in our experiments, was removed via a 2nd-order diffusion mechanism. As expected, the desorption activation energies of the 2nd-order diffusion kinetics were much larger than the decay mechanism`s activation energies. Our results also suggest, at least for particle sizes < 841 {mu}m, < 106 {mu}m, and < 37 {mu}m, that the coal particle size has little effect on the desorption activation barriers.

  8. Study on the characterization and thermal decomposition of uranium compounds by thermogravimetry (TG) and differential scanning calorimetry (DSC)

    International Nuclear Information System (INIS)

    Dantas, J.M.; Abrao, A.

    1981-04-01

    A contribution to the characterization of several uranium compounds obtained at the IPEN' Uranium Pilot Plant is given. Particularly, samples of ammonium diuranate (ADU) and uranium oxides were studied. The main objective was to know the stoichiometry of the ADU and the oxides resulting from its thermal transformation. ADU samples were prepared by batchwise precipitation, stationary dewatering into stove and batchwise thermal decomposition, or, alternatively, continuous precipitation, continuous filtration, continuous drying and continuous thermal decomposition inside a temperature gradient electrical furnace. All ADU were precipitated using NH 3 gas from uranul sulfate or uranyl nitrate solutions. The thermal decomposition of ADU and uranium oxides were studied in an air atmosphere by thermogravimetry (TG) and differential scanning calorimetry (DSC). Any correlation between the parameters of precipitation, drying, calcination and the hystory of the obtaintion of the several uraniumm compounds and their initial and final composition was looked for. Heating program was established to have the U 3 O 8 oxide as the final product. Intermediary phases were tentatively identified. Temperatures at which occurred the absorption water elimination, crystallization water elimination, evolution or oxidation of NH 3 , decomposition of NO -3 ion and oxygen evolution and the exo- and endothermic process for each sample were identified. (Author) [pt

  9. Extending differential optical absorption spectroscopy for limb measurements in the UV

    Directory of Open Access Journals (Sweden)

    J. Puķīte

    2010-05-01

    Full Text Available Methods of UV/VIS absorption spectroscopy to determine the constituents in the Earth's atmosphere from measurements of scattered light are often based on the Beer-Lambert law, like e.g. Differential Optical Absorption Spectroscopy (DOAS. While the Beer-Lambert law is strictly valid for a single light path only, the relation between the optical depth and the concentration of any absorber can be approximated as linear also for scattered light observations at a single wavelength if the absorption is weak. If the light path distribution is approximated not to vary with wavelength, also linearity between the optical depth and the product of the cross-section and the concentration of an absorber can be assumed. These assumptions are widely made for DOAS applications for scattered light observations.

    For medium and strong absorption of scattered light (e.g. along very long light-paths like in limb geometry the relation between the optical depth and the concentration of an absorber is no longer linear. In addition, for broad wavelength intervals the differences in the travelled light-paths at different wavelengths become important, especially in the UV, where the probability for scattering increases strongly with decreasing wavelength.

    However, the DOAS method can be extended to cases with medium to strong absorptions and for broader wavelength intervals by the so called air mass factor modified (or extended DOAS and the weighting function modified DOAS. These approaches take into account the wavelength dependency of the slant column densities (SCDs, but also require a priori knowledge for the air mass factor or the weighting function from radiative transfer modelling.

    We describe an approach that considers the fitting results obtained from DOAS, the SCDs, as a function of wavelength and vertical optical depth and expands this function into a Taylor series of both quantities. The Taylor coefficients are then applied as

  10. Tissue differentiation by diffuse reflectance spectroscopy for automated oral and maxillofacial laser surgery: ex vivo pilot study

    Science.gov (United States)

    Zam, Azhar; Stelzle, Florian; Tangermann-Gerk, Katja; Adler, Werner; Nkenke, Emeka; Schmidt, Michael; Douplik, Alexandre

    2010-02-01

    Remote laser surgery lacks of haptic feedback during the laser ablation of tissue. Hence, there is a risk of iatrogenic damage or destruction of anatomical structures like nerves or salivary glands. Diffuse reflectance spectroscopy provides a straightforward and simple approach for optical tissue differentiation. We measured diffuse reflectance from seven various tissue types ex vivo. We applied Linear Discriminant Analysis (LDA) to differentiate the seven tissue types and computed the area under the ROC curve (AUC). Special emphasis was taken on the identification of nerves and salivary glands as the most crucial tissue for maxillofacial surgery. The results show a promise for differentiating tissues as guidance for oral and maxillofacial laser surgery by means of diffuse reflectance.

  11. Rapid differentiation of Listeria monocytogenes epidemic clones III and IV and their intact compared with heat-killed populations using Fourier transform infrared spectroscopy and chemometrics.

    Science.gov (United States)

    Nyarko, Esmond B; Puzey, Kenneth A; Donnelly, Catherine W

    2014-06-01

    The objectives of this study were to determine if Fourier transform infrared (FT-IR) spectroscopy and multivariate statistical analysis (chemometrics) could be used to rapidly differentiate epidemic clones (ECs) of Listeria monocytogenes, as well as their intact compared with heat-killed populations. FT-IR spectra were collected from dried thin smears on infrared slides prepared from aliquots of 10 μL of each L. monocytogenes ECs (ECIII: J1-101 and R2-499; ECIV: J1-129 and J1-220), and also from intact and heat-killed cell populations of each EC strain using 250 scans at a resolution of 4 cm(-1) in the mid-infrared region in a reflectance mode. Chemometric analysis of spectra involved the application of the multivariate discriminant method for canonical variate analysis (CVA) and linear discriminant analysis (LDA). CVA of the spectra in the wavelength region 4000 to 600 cm(-1) separated the EC strains while LDA resulted in a 100% accurate classification of all spectra in the data set. Further, CVA separated intact and heat-killed cells of each EC strain and there was 100% accuracy in the classification of all spectra when LDA was applied. FT-IR spectral wavenumbers 1650 to 1390 cm(-1) were used to separate heat-killed and intact populations of L. monocytogenes. The FT-IR spectroscopy method allowed discrimination between strains that belong to the same EC. FT-IR is a highly discriminatory and reproducible method that can be used for the rapid subtyping of L. monocytogenes, as well as for the detection of live compared with dead populations of the organism. Fourier transform infrared (FT-IR) spectroscopy and multivariate statistical analysis can be used for L. monocytogenes source tracking and for clinical case isolate comparison during epidemiological investigations since the method is capable of differentiating epidemic clones and it uses a library of well-characterized strains. The FT-IR method is potentially less expensive and more rapid compared to genetic

  12. Characterization of toners and inkjets by laser ablation spectrochemical methods and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy

    International Nuclear Information System (INIS)

    Trejos, Tatiana; Corzo, Ruthmara; Subedi, Kiran; Almirall, José

    2014-01-01

    Detection and sourcing of counterfeit currency, examination of counterfeit security documents and determination of authenticity of medical records are examples of common forensic document investigations. In these cases, the physical and chemical composition of the ink entries can provide important information for the assessment of the authenticity of the document or for making inferences about common source. Previous results reported by our group have demonstrated that elemental analysis, using either Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) or Laser Ablation Induced Breakdown Spectroscopy (LIBS), provides an effective, practical and robust technique for the discrimination of document substrates and writing inks with minimal damage to the document. In this study, laser-based methods and Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) methods were developed, optimized and validated for the forensic analysis of more complex inks such as toners and inkjets, to determine if their elemental composition can differentiate documents printed from different sources and to associate documents that originated from the same printing source. Comparison of the performance of each of these methods is presented, including the analytical figures of merit, discrimination capability and error rates. Different calibration strategies resulting in semi-quantitative and qualitative analysis, comparison methods (match criteria) and data analysis and interpretation tools were also developed. A total of 27 black laser toners originating from different manufacturing sources and/or batches were examined to evaluate the discrimination capability of each method. The results suggest that SEM-EDS offers relatively poor discrimination capability for this set (∼ 70.7% discrimination of all the possible comparison pairs or a 29.3% type II error rate). Nonetheless, SEM-EDS can still be used as a complementary method of analysis since it has

  13. Characterization of toners and inkjets by laser ablation spectrochemical methods and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy

    Science.gov (United States)

    Trejos, Tatiana; Corzo, Ruthmara; Subedi, Kiran; Almirall, José

    2014-02-01

    Detection and sourcing of counterfeit currency, examination of counterfeit security documents and determination of authenticity of medical records are examples of common forensic document investigations. In these cases, the physical and chemical composition of the ink entries can provide important information for the assessment of the authenticity of the document or for making inferences about common source. Previous results reported by our group have demonstrated that elemental analysis, using either Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) or Laser Ablation Induced Breakdown Spectroscopy (LIBS), provides an effective, practical and robust technique for the discrimination of document substrates and writing inks with minimal damage to the document. In this study, laser-based methods and Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) methods were developed, optimized and validated for the forensic analysis of more complex inks such as toners and inkjets, to determine if their elemental composition can differentiate documents printed from different sources and to associate documents that originated from the same printing source. Comparison of the performance of each of these methods is presented, including the analytical figures of merit, discrimination capability and error rates. Different calibration strategies resulting in semi-quantitative and qualitative analysis, comparison methods (match criteria) and data analysis and interpretation tools were also developed. A total of 27 black laser toners originating from different manufacturing sources and/or batches were examined to evaluate the discrimination capability of each method. The results suggest that SEM-EDS offers relatively poor discrimination capability for this set (~ 70.7% discrimination of all the possible comparison pairs or a 29.3% type II error rate). Nonetheless, SEM-EDS can still be used as a complementary method of analysis since it has

  14. Study of non stoichiometric pure and Zr-Doped yttria surfaces by X-Ray photoelectron spectroscopy and scanning electron microscopy

    International Nuclear Information System (INIS)

    Gautier, M.; Duraud, J.P.; Jollet, F.; Thromat, N.; Maire, P.; Le Gressus, C.

    1988-01-01

    Surfaces of oxygen-deficient yttrium oxide, pure or Zr-doped, have been studied by means of X-ray photoelectron spectroscopy and scanning electron microscopy. The bulk local geometric structure of these non-stoichiometric compounds was previously determined around the Y atom by an EXAFS (Extended X-ray absorption fine structure) study. The local electronic structure around both Y and O, at the surface, was investigated by X-ray photoelectron spectroscopy. The partial transfer of the electronic distribution between the anion and the cation was probed using the Auger parameter. Coupling of these experiments with microscopic observations show that: - In the pure oxygen-deficient sample, the concentration of oxygen vacancies appears to be increased at the grain boundaries. - The Auger parameter shows upon reduction an evolution of the Y-O bond towards a more covalent one, this evolution being modulated with the presence of Zr0 2

  15. Testing antifreeze protein from the longhorn beetle Rhagium mordax as a kinetic gas hydrate inhibitor using a high-pressure micro differential scanning calorimeter

    DEFF Research Database (Denmark)

    Daraboina, Nagu; Perfeldt, Christine Malmos; von Solms, Nicolas

    2015-01-01

    pressure micro differential scanning calorimeter HP-mu DSC VII (Setaram Inc.) containing two 50 cc high pressure cells (maximum operating pressure 40 MPa; temperature range -40 to 120 degrees C) was employed to observe methane hydrate formation and decomposition in the presence of hyperactive antifreeze...

  16. Excess heat capacity of the (Li1?xCax)F1+x liquid solution determined by differential scanning calorimetry and drop calorimetry

    NARCIS (Netherlands)

    Capelli, E.; Benes, O.; Konings, R.J.M.

    2014-01-01

    The work presents the measured heat capacity of the (Li1?xCax)F1+x liquid solution. Four samples with different compositions have been prepared and measured using a Differential Scanning Calorimeter. Since this technique was newly adopted for measuring encapsulated fluoride samples, some

  17. Characterization of the molecular distribution of drugs in glassy solid dispersions at the nano-meter scale, using differential scanning calorimetry and gravimetric water vapour sorption techniques

    NARCIS (Netherlands)

    van Drooge, D J; Hinrichs, W L J; Visser, M R; Frijlink, H W

    2006-01-01

    The molecular distribution in fully amorphous solid dispersions consisting of poly(vinylpyrrolidone) (PVP)-diazepam and inulin-diazepam was studied. One glass transition temperature (T-g), as determined by temperature modulated differential scanning calorimetry (TMDSC), was observed in PVP-diazepam

  18. Reversible amorphous-crystalline phase changes in a wide range of Se1-xTex alloys studied using ultrafast differential scanning calorimetry

    NARCIS (Netherlands)

    Vermeulen, Paul. A.; Momand, Jamo; Kooi, Bart J.

    The reversible amorphous-crystalline phase change in a chalcogenide material, specifically the Se1-xTex alloy, has been investigated for the first time using ultrafast differential scanning calorimetry. Heating rates and cooling rates up to 5000 K/s were used. Repeated reversible

  19. Autonomous long-term trace gas measurements using Long-Path Differential Optical Absorption Spectroscopy

    Science.gov (United States)

    Nasse, Jan-Marcus; Pöhler, Denis; Eger, Philipp; Schmitt, Stefan; Friess, Udo; Platt, Ulrich

    2017-04-01

    Long-Path DOAS (Differential Optical Absorption Spectroscopy) is a well-established, very specific and reliable remote sensing technique for the observation of a large variety of trace gases. So far DOAS has been mostly applied in the UV-Vis spectral region; detectable species are for example ClO, OClO, BrO, OBrO, IO, OIO, I2, OIO, O3, formaldehyde, glyoxal, NO2, H2O, O4, or SO2. In the Long Path DOAS setup, a dedicated light source and a measurement path of up to 10 km between a telescope and a reflector yield continuous path averaged concentrations independent of solar radiation and still on scales below the ground pixel sizes of satellite instruments. Here we present an advanced LP-DOAS instrument incorporating several technical improvements to a setup that allows for the first time autonomous and continuous long term measurements with very high measurement accuracy necessary for the measurement of low trace gas concentrations. The setup uses an optical fiber bundle in the telescope for transmission and reception of the measurement signal. The traditional Xe-arc lamp has been replaced by a Laser Driven Light Source with a long life time and very good optical stability. Using this light source also allows an improved wavelength selective coupling from light source into the fiber which reduces stray light. The coupling and configuration of the optical fiber was optimised compared to previous designs to maximise light throughput and reduce stray light. Additionally, the fibers were treated in order to reduce noise caused by irregular grating illumination. These changes drastically lower detection limits (e.g. to 1 pptv for BrO or 8 pptv for ClO) and improve the long-term reliability. To facilitate an autonomous operation, the measurement software incorporates features such as an automatic reflector search and intensity optimisation as well as a selection from the available measurement paths based on atmospheric visibility. Since January 2016, we are successfully

  20. Retrieval interval mapping, a tool to optimize the spectral retrieval range in differential optical absorption spectroscopy

    Science.gov (United States)

    Vogel, L.; Sihler, H.; Lampel, J.; Wagner, T.; Platt, U.

    2012-06-01

    Remote sensing via differential optical absorption spectroscopy (DOAS) has become a standard technique to identify and quantify trace gases in the atmosphere. The technique is applied in a variety of configurations, commonly classified into active and passive instruments using artificial and natural light sources, respectively. Platforms range from ground based to satellite instruments and trace-gases are studied in all kinds of different environments. Due to the wide range of measurement conditions, atmospheric compositions and instruments used, a specific challenge of a DOAS retrieval is to optimize the parameters for each specific case and particular trace gas of interest. This becomes especially important when measuring close to the detection limit. A well chosen evaluation wavelength range is crucial to the DOAS technique. It should encompass strong absorption bands of the trace gas of interest in order to maximize the sensitivity of the retrieval, while at the same time minimizing absorption structures of other trace gases and thus potential interferences. Also, instrumental limitations and wavelength depending sources of errors (e.g. insufficient corrections for the Ring effect and cross correlations between trace gas cross sections) need to be taken into account. Most often, not all of these requirements can be fulfilled simultaneously and a compromise needs to be found depending on the conditions at hand. Although for many trace gases the overall dependence of common DOAS retrieval on the evaluation wavelength interval is known, a systematic approach to find the optimal retrieval wavelength range and qualitative assessment is missing. Here we present a novel tool to determine the optimal evaluation wavelength range. It is based on mapping retrieved values in the retrieval wavelength space and thus visualize the consequence of different choices of retrieval spectral ranges, e.g. caused by slightly erroneous absorption cross sections, cross correlations and

  1. a 530-590 GHZ Schottky Heterodyne Receiver for High-Resolution Molecular Spectroscopy with Lille's Fast-Scan Fully Solid-State DDS Spectrometer

    Science.gov (United States)

    Pienkina, A.; Margulès, L.; Motiyenko, R. A.; Wiedner, Martina C.; Maestrini, Alain; Defrance, Fabien

    2017-06-01

    Laboratory spectroscopy, especially at THz and mm-wave ranges require the advances in instrumentation techniques to provide high resolution of the recorded spectra with precise frequency measurement that facilitates the mathematical treatment. We report the first implementation of a Schottky heterodyne receiver, operating at room temperature and covering the range between 530 and 590 GHz, for molecular laboratory spectroscopy. A 530-590 GHz non-cryogenic Schottky solid-state receiver was designed at LERMA, Observatoire de Paris and fabricated in partnership with LPN- CNRS (Laboratoire de Photonique et de Nanostructures), and was initially developed for ESA Jupiter Icy Moons Explorer (JUICE), intended to observe Jupiter and its icy moon atmospheres. It is based on a sub-harmonic Schottky diode mixer, designed and fabricated at LERMA-LPN, pumped by a Local Oscillator (LO), consisting of a frequency Amplifier/Multiplier chains (AMCs) from RPG (Radiometer Physics GmBh). The performance of the receiver was demonstrated by absorption spectroscopy of CH_3CH_2CN with Lille's fast-scan DDS spectrometer. A series of test measurements showed the receiver's good sensitivity, stability and frequency accuracy comparable to those of 4K QMC bolometers, thus making room-temperature Schottky receiver a competitive alternative to 4K QMC bolometers to laboratory spectroscopy applications. We will present the first results with such a combination of a compact room temperature Schottky heterodyne receiver and a fast-scan DDS spectrometer. J. Treuttel, L. Gatilova, A. Maestrini et al., 2016, IEEE Trans. Terahertz Science and Tech., 6, 148-155. This work was funded by the French ANR under the Contract No. ANR-13-BS05-0008-02 IMOLABS.

  2. Evidence of a spin resonance mode in the iron-based superconductor Ba(0.6)K(0.4)Fe2As2 from scanning tunneling spectroscopy.

    Science.gov (United States)

    Shan, Lei; Gong, Jing; Wang, Yong-Lei; Shen, Bing; Hou, Xingyuan; Ren, Cong; Li, Chunhong; Yang, Huan; Wen, Hai-Hu; Li, Shiliang; Dai, Pengcheng

    2012-06-01

    We used high-resolution scanning tunneling spectroscopy to study the hole-doped iron pnictide superconductor Ba(0.6)K(0.4)Fe(2)As(2) (T(c)=38 K). Features of a bosonic excitation (mode) are observed in the measured quasiparticle density of states. The bosonic features are intimately associated with the superconducting order parameter and have a mode energy of ~14 meV, similar to the spin resonance measured by inelastic neutron scattering. These results indicate a strong electron-spin excitation coupling in iron pnictide superconductors, similar to that in high-T(c) copper oxide superconductors.

  3. Analytical electron microscope based on scanning transmission electron microscope with wavelength dispersive x-ray spectroscopy to realize highly sensitive elemental imaging especially for light elements

    International Nuclear Information System (INIS)

    Koguchi, Masanari; Tsuneta, Ruriko; Anan, Yoshihiro; Nakamae, Koji

    2017-01-01

    An analytical electron microscope based on the scanning transmission electron microscope with wavelength dispersive x-ray spectroscopy (STEM-WDX) to realize highly sensitive elemental imaging especially for light elements has been developed. In this study, a large-solid-angle multi-capillary x-rays lens with a focal length of 5 mm, long-time data acquisition (e.g. longer than 26 h), and a drift-free system made it possible to visualize boron-dopant images in a Si substrate at a detection limit of 0.2 atomic percent. (paper)

  4. Surface modification of Sylgard 184 polydimethylsiloxane by 254 nm excimer radiation and characterization by contact angle goniometry, infrared spectroscopy, atomic force and scanning electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Waddell, Emanuel A. [University of Alabama in Huntsville, Huntsville, AL (United States)], E-mail: ewaddell@chemistry.uah.edu; Shreeves, Stephen [University of Alabama in Huntsville, Huntsville, AL (United States); Carrell, Holly; Perry, Christopher [Oakwood College, Huntsville, AL (United States); Reid, Branden A. [Morgan State University, Baltimore, MD (United States); McKee, James [University of Alabama in Birmingham, Birmingham, AL (United States)

    2008-06-30

    The modification of polydimethylsiloxane (PDMS) by narrow band 254 nm excimer radiation under a nitrogen atmosphere was characterized by contact angle goniometry, attenuated total reflectance infrared spectroscopy, atomic force and scanning electron microscopy. UV irradiation results in the formation of the carboxylic acids that influences the wettability of the surface. Continued exposure results in the formation of an inorganic surface (SiO{sub x} (1 < x < 2)) which hinders the ability to continually increase the wettability. The continuity of this inorganic layer is disrupted by the formation of surface cracks. These results have implications in the fabrication and chemical modification of microfluidic or micro-electro-mechanical systems.

  5. Surface modification of Sylgard 184 polydimethylsiloxane by 254 nm excimer radiation and characterization by contact angle goniometry, infrared spectroscopy, atomic force and scanning electron microscopy

    Science.gov (United States)

    Waddell, Emanuel A.; Shreeves, Stephen; Carrell, Holly; Perry, Christopher; Reid, Branden A.; McKee, James

    2008-06-01

    The modification of polydimethylsiloxane (PDMS) by narrow band 254 nm excimer radiation under a nitrogen atmosphere was characterized by contact angle goniometry, attenuated total reflectance infrared spectroscopy, atomic force and scanning electron microscopy. UV irradiation results in the formation of the carboxylic acids that influences the wettability of the surface. Continued exposure results in the formation of an inorganic surface (SiO x (1 < x < 2)) which hinders the ability to continually increase the wettability. The continuity of this inorganic layer is disrupted by the formation of surface cracks. These results have implications in the fabrication and chemical modification of microfluidic or micro-electro-mechanical systems.

  6. Differentiation of hemangioblastomas from pilocytic astrocytomas using 3-T magnetic resonance perfusion-weighted imaging and MR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    She, D.J.; Xing, Z.; Zeng, Z.; Cao, D.R. [First Affiliated Hospital of Fujian Medical University, Department of Radiology, Fuzhou, Fujian (China); Shang, X.Y. [University of California, San Diego, Department of Medicine and the Moores UCSD Cancer Center, La Jolla, CA (United States)

    2015-03-01

    Hemangioblastomas and pilocytic astrocytomas (PAs) present similar imaging features on conventional MR imaging, making differential diagnosis a challenge. The purpose of this study was to evaluate the usefulness of dynamic susceptibility-weighted contrast-enhanced perfusion-weighted imaging (DSC-PWI) and proton MR spectroscopic imaging in the differentiation of hemangioblastomas and PAs. A 3.0-T MR imaging unit was used to perform DSC-PWI and conventional MR imaging on 14 patients with hemangioblastomas and 22 patients with PAs. Four patients with hemangioblastomas and 10 PA patients also underwent proton MR spectroscopy. Parameters of relative peak height (rPH) and relative percentage of signal intensity recovery (rPSR) were acquired by DSC-PWI and variables of N-acetylaspasrtate (NAA)/creatine (Cr), choline (Cho)/Cr, and lactate-lipid (Lac-Lip)/Cr by MR spectroscopy. The sensitivity, specificity, and the area under the receiver operating characteristic curve of all analyzed parameters at respective cutoff values were determined. Higher rPH but lower rPSR values were detected in hemangioblastomas compared to PAs. The NAA/Cr ratio was significantly lower in hemangioblastomas compared with PAs. The threshold values ≥3.2 for rPH provide sensitivity, specificity, positive predictive values, and negative predictive values of 85.7, 95.5, 92.3, and 91.3 %, respectively, for differentiating hemangioblastomas from PAs. The optimal threshold values were ≤0.9 for rPSR and ≤1.5 for NAA/Cr ratios in tumor. Significantly higher rPH and lower NAA/Cr were seen in patients with hemangioblastomas when compared with PA patients, suggesting that DSC-PWI and proton MR spectroscopy are helpful in the characterization and differentiation of these two types of tumors. (orig.)

  7. Differentiating intraparenchymal hemorrhage from contrast extravasation on post-procedural noncontrast CT scan in acute ischemic stroke patients undergoing endovascular treatment

    International Nuclear Information System (INIS)

    Payabvash, Seyedmehdi; Qureshi, Mushtaq H.; Khan, Shayaan M.; Khan, Mahnoor; Majidi, Shahram; Pawar, Swaroop; Qureshi, Adnan I.

    2014-01-01

    This study aimed to identify the imaging characteristics that can help differentiate intraparenchymal hemorrhage from benign contrast extravasation on post-procedural noncontrast CT scan in acute ischemic stroke patients after endovascular treatment. We reviewed the clinical and imaging records of all acute ischemic stroke patients who underwent endovascular treatment in two hospitals over a 3.5-year period. The immediate post-procedural CT scan was evaluated for the presence of hyperdense lesion(s). The average attenuation of the lesion(s) was measured. Intraparenchymal hemorrhage was defined as a persistent hyperdensity visualized on follow-up CT scan, 24 h or greater after the procedure. Of the 135 patients studied, 74 (55 %) patients had hyperdense lesion(s) on immediate post-procedural CT scan. Follow-up scans confirmed the diagnosis of intraparenchymal hemorrhage in 20 of these 74 patients. A receiver operating characteristic analysis showed that the average attenuation of the most hyperdense lesion can differentiate intraparenchymal hemorrhage from contrast extravasation with an area under the curve of 0.78 (p = 0.001). An average attenuation of <50 Hounsfield units (HU) in the most visually hyperattenuating hyperdense lesion had 100 % specificity and 56 % sensitivity for identification of contrast extravasations. Petechial hyperdensity was seen in 46/54 (85 %) patients with contrast extravasation versus 9/20 (45 %) patients with intraparenchymal hemorrhage on the immediate post-procedural CT scan (p < 0.001). An average attenuation <50 HU of the most hyperattenuating hyperdense parenchymal lesion on immediate post-procedural CT scan was very specific for differentiating contrast extravasation from intraparenchymal hemorrhage in acute ischemic stroke patients after endovascular treatment. (orig.)

  8. Differentiating intraparenchymal hemorrhage from contrast extravasation on post-procedural noncontrast CT scan in acute ischemic stroke patients undergoing endovascular treatment

    Energy Technology Data Exchange (ETDEWEB)

    Payabvash, Seyedmehdi [Zeenat Qureshi Stroke Institute, Minneapolis, MN (United States); University of Minnesota, Department of Radiology, Minneapolis, MN (United States); Qureshi, Mushtaq H.; Khan, Shayaan M.; Khan, Mahnoor; Majidi, Shahram; Pawar, Swaroop; Qureshi, Adnan I. [Zeenat Qureshi Stroke Institute, Minneapolis, MN (United States)

    2014-09-15

    This study aimed to identify the imaging characteristics that can help differentiate intraparenchymal hemorrhage from benign contrast extravasation on post-procedural noncontrast CT scan in acute ischemic stroke patients after endovascular treatment. We reviewed the clinical and imaging records of all acute ischemic stroke patients who underwent endovascular treatment in two hospitals over a 3.5-year period. The immediate post-procedural CT scan was evaluated for the presence of hyperdense lesion(s). The average attenuation of the lesion(s) was measured. Intraparenchymal hemorrhage was defined as a persistent hyperdensity visualized on follow-up CT scan, 24 h or greater after the procedure. Of the 135 patients studied, 74 (55 %) patients had hyperdense lesion(s) on immediate post-procedural CT scan. Follow-up scans confirmed the diagnosis of intraparenchymal hemorrhage in 20 of these 74 patients. A receiver operating characteristic analysis showed that the average attenuation of the most hyperdense lesion can differentiate intraparenchymal hemorrhage from contrast extravasation with an area under the curve of 0.78 (p = 0.001). An average attenuation of <50 Hounsfield units (HU) in the most visually hyperattenuating hyperdense lesion had 100 % specificity and 56 % sensitivity for identification of contrast extravasations. Petechial hyperdensity was seen in 46/54 (85 %) patients with contrast extravasation versus 9/20 (45 %) patients with intraparenchymal hemorrhage on the immediate post-procedural CT scan (p < 0.001). An average attenuation <50 HU of the most hyperattenuating hyperdense parenchymal lesion on immediate post-procedural CT scan was very specific for differentiating contrast extravasation from intraparenchymal hemorrhage in acute ischemic stroke patients after endovascular treatment. (orig.)

  9. Diffuse reflectance spectroscopy for optical soft tissue differentiation as remote feedback control for tissue-specific laser surgery.

    Science.gov (United States)

    Stelzle, Florian; Tangermann-Gerk, Katja; Adler, Werner; Zam, Azhar; Schmidt, Michael; Douplik, Alexandre; Nkenke, Emeka

    2010-04-01

    Laser surgery does not provide haptic feedback for operating layer-by-layer and thereby preserving vulnerable anatomical structures like nerve tissue or blood vessels. Diffuse reflectance spectra can facilitate remote optical tissue differentiation. It is the aim of the study to use this technique on soft tissue samples, to set a technological basis for a remote optical feedback system for tissue-specific laser surgery. Diffuse reflectance spectra (wavelength range: 350-650 nm) of ex vivo types of soft tissue (a total of 10,800 spectra) of the midfacial region of domestic pigs were remotely measured under reduced environmental light conditions and analyzed in order to differentiate between skin, mucosa, muscle, subcutaneous fat, and nerve tissue. We performed a principal components (PC) analysis (PCA) to reduce the number of variables. Linear discriminant analysis (LDA) was utilized for classification. For the tissue differentiation, we calculated the specificity and sensitivity by receiver operating characteristic (ROC) analysis and the area under curve (AUC). Six PCs were found to be adequate for tissue differentiation with diffuse reflectance spectra using LDA. All of the types of soft tissue could be differentiated with high specificity and sensitivity. Only the tissue pairs nervous tissue/fatty tissue and nervous tissue/mucosa showed a decline of differentiation due to bio-structural similarity. However, both of these tissue pairs could still be differentiated with a specificity and sensitivity of more than 90%. Analyzing diffuse reflectance spectroscopy with PCA and LDA allows for remote differentiation of biological tissue. Considering the limitations of the ex vivo conditions, the obtained results are promising and set a basis for the further development of a feedback system for tissue-specific laser surgery. (c) 2010 Wiley-Liss, Inc.

  10. Experimental determination of the (vapor + liquid) equilibrium data of binary mixtures of fatty acids by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Matricarde Falleiro, Rafael M. [LPT, Department of Chemical Processes (DPQ), School of Chemical Engineering, University of Campinas (UNICAMP), P.O. Box 6066, 13083-970 Campinas, SP (Brazil); Meirelles, Antonio J.A. [EXTRAE, Department of Food Engineering (DEA), School of Food Engineering, University of Campinas (UNICAMP), P.O. Box 6121, 13083-862 Campinas, SP (Brazil); Kraehenbuehl, Maria A., E-mail: mak@feq.unicamp.b [LPT, Department of Chemical Processes (DPQ), School of Chemical Engineering, University of Campinas (UNICAMP), P.O. Box 6066, 13083-970 Campinas, SP (Brazil)

    2010-01-15

    (Vapor + liquid) equilibrium (VLE) data for three binary mixtures of saturated fatty acids were obtained by differential scanning calorimetry (DSC). However, changes in the calorimeter pressure cell and the use of hermetic pans with holes (phi = 250 mm) in the lids were necessary to make it possible to apply this analytical technique, obtaining accurate results with smaller samples and shorter operational times. The systems evaluated in this study were: myristic acid (C{sub 14:0}) + palmitic acid (C{sub 16:0}), myristic acid (C{sub 14:0}) + stearic acid (C{sub 18:0}), and palmitic acid (C{sub 16:0}) + stearic acid (C{sub 18:0}), all measured at 50 mm Hg and with mole fractions between 0.0 and 1.0 in relation to the most volatile component of each diagram. The fugacity coefficients for the components in the vapor phase were calculated using the Hayden and O'Connell method [J.G. Hayden, J.P. O'Connell, Ind. Eng. Chem. Process Design Develop. 14 (3) (1975) 209-216] and the activity coefficients for the liquid phase were correlated with the traditional g{sup E} models (NRTL [H. Renon, J.M. Prausnitz, Aiche J. 14 (1968) 135-144], UNIQUAC [D.S. Abrams, J.M. Prausnitz, Aiche J. 21 (1975) 116-128], and Wilson [J.M. Prausnitz, N.L. Linchtenthaler, E.G. Azevedo, Molecular Thermodynamics of Fluid-phase Equilibria, River-Prentice Hall, Upper Saddle, 1999]). The sets of parameters were then compared in order to determine which adjustments best represented the VLE.

  11. An evaluation of the transition temperature range of super-elastic orthodontic NiTi springs using differential scanning calorimetry.

    Science.gov (United States)

    Barwart, O; Rollinger, J M; Burger, A

    1999-10-01

    Differential scanning calorimetry (DSC) was used to determine the transition temperature ranges (TTR) of four types of super-elastic orthodontic nickel-titanium coil springs (Sentalloy). A knowledge of the TTR provides information on the temperature at which a NiTi wire or spring can assume superelastic properties and when this quality disappears. The spring types in this study can be distinguished from each other by their characteristic TTR during cooling and heating. For each tested spring type a characteristic TTR during heating (austenite transformation) and cooling (martensite transformation) was evaluated. The hysteresis of the transition temperature, found between cooling and heating, was 3.4-5.2 K. Depending on the spring type the austenite transformation started (As) at 9.7-17.1 degrees C and finished (Af) at 29.2-37 degrees C. The martensite transformation starting temperature (Ms) was evaluated at 32.6-25.4 degrees C, while Mf (martensite transformation finishing temperature) was 12.7-6.5 degrees C. The results show that the springs become super-elastic when the temperature increases and As is reached. They undergo a loss of super-elastic properties and a rapid decrease in force delivery when they are cooled to Mf. For the tested springs, Mf and As were found to be below room temperature. Thus, at room temperature and some degrees lower, all the tested springs exert super-elastic properties. For orthodontic treatment this means the maintenance of super-elastic behaviour, even when mouth temperature decreases to about room temperature as can occur, for example, during meals.

  12. State of the water in crosslinked sulfonated poly(ether ether ketone). Two-dimensional differential scanning calorimetry correlation mapping

    Energy Technology Data Exchange (ETDEWEB)

    Al Lafi, Abdul G. [Department of Chemistry, Atomic Energy Commission, Damascus, P.O. Box 6091 (Syrian Arab Republic); Hay, James N., E-mail: cscientific9@aec.org.sy [The School of Metallurgy and Materials, College of Physical Sciences and Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2015-07-20

    Highlights: • 2D-DSC mapping was applied to analyze the heat flow responses of hydrated crosslinked sPEEK. • Two types of loosely bond water were observed. • The first was bond to the sulfonic acid groups and increased with ion exchange capacity. • The second was attributed to the polar groups introduced by ions irradiation and increased with crosslinking degree. • DSC combined with 2D mapping provides a powerful tool for polymer structural determination. - Abstract: This paper reports the first application of two-dimensional differential scanning calorimetry correlation mapping, 2D-DSC-CM to analyze the heat flow responses of sulphonated poly(ether ether ketone), sPEEK, films having different ion exchange capacity and degrees of crosslinks. With the help of high resolution and high sensitivity of 2D-DSC-CM, it was possible to locate two types of loosely bound water within the structure of crosslinked sPEEK. The first was bound to the sulfonic acid groups and dependent on the ion exchange capacity of the sPEEK. The second was bound to other polar groups, either introduced by irradiation with ions and dependent on the crosslinking degree or present in the polymer such as the carbonyl groups or terminal units. The results suggest that the ability of the sulfonic acid groups in the crosslinked sPEEK membranes to adsorb water molecules is increased by crosslinking, probably due to the better close packing efficiency of the crosslinked samples. DSC combined with 2D correlation mapping provides a fast and powerful tool for polymer structural determination.

  13. Differentiation of Asian ginseng, American ginseng and Notoginseng by Fourier transform infrared spectroscopy combined with two-dimensional correlation infrared spectroscopy

    Science.gov (United States)

    Lu, Guang-hua; Zhou, Qun; Sun, Su-qin; Leung, Kelvin Sze-yin; Zhang, Hao; Zhao, Zhong-zhen

    2008-07-01

    The herbal materials of Asian ginseng (the root of Panax ginseng), American ginseng (the root of Panax quinquefolius) and Notoginseng (the root of Panax notoginseng) were differentiated by conventional Fourier transform infrared spectroscopy (1D-FTIR) and two-dimensional (2D) correlation FTIR applying a thermal perturbation. Altogether 30 samples were collected and analyzed. Their entire 1D-FTIR spectra in the range of 4000-400 cm -1 and 2D-FTIR spectra in the region of 850-1530 cm -1 were generally similar based on the peaks position and intensities. This indicated the chemical constituents in these species of herbs were not distinctively different. However, variation in peak intensity were observed at about 1640 cm -1, 1416 cm -1, 1372 cm -1 and 1048 cm -1 in the 1D-FTIR spectra among these species for their ease differentiation. Clustering analysis of 1D-FTIR showed that these species located in different clusters. Much difference in their second derivative FTIR pattern among the three species also provided information for easy differentiation. These species of herbs were further identified based on the positions and intensities of relatively strong auto-peaks, positive or negative cross-peaks in their 2D-FTIR spectra. The findings provide a rapid and new operational procedure for the differentiation of these notable herbs. The visual and colorful 2D-FTIR spectra can provide dynamic structural information of chemical components in analyte and demonstrated as a powerful and useful approach for herbs identification.

  14. In Situ Industrial Bimetallic Catalyst Characterization using Scanning Transmission Electron Microscopy and X-ray Absorption Spectroscopy at One Atmosphere and Elevated Temperature.

    Science.gov (United States)

    Prestat, Eric; Kulzick, Matthew A; Dietrich, Paul J; Smith, Mr Matthew; Tien, Mr Eu-Pin; Burke, M Grace; Haigh, Sarah J; Zaluzec, Nestor J

    2017-08-18

    We have developed a new experimental platform for in situ scanning transmission electron microscope (STEM) energy dispersive X-ray spectroscopy (EDS) which allows real time, nanoscale, elemental and structural changes to be studied at elevated temperature (up to 1000 °C) and pressure (up to 1 atm). Here we demonstrate the first application of this approach to understand complex structural changes occurring during reduction of a bimetallic catalyst, PdCu supported on TiO 2 , synthesized by wet impregnation. We reveal a heterogeneous evolution of nanoparticle size, distribution, and composition with large differences in reduction behavior for the two metals. We show that the data obtained is complementary to in situ STEM electron energy loss spectroscopy (EELS) and when combined with in situ X-ray absorption spectroscopy (XAS) allows correlation of bulk chemical state with nanoscale changes in elemental distribution during reduction, facilitating new understanding of the catalytic behavior for this important class of materials. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  15. Investigation of gene expressions in differentiated cell derived bone marrow stem cells during bone morphogenetic protein-4 treatments with Fourier transform infrared spectroscopy

    Science.gov (United States)

    Zafari, Jaber; Jouni, Fatemeh Javani; Ahmadvand, Ali; Abdolmaleki, Parviz; Soodi, Malihe; Zendehdel, Rezvan

    2017-02-01

    A model was set up to predict the differentiation patterns based on the data extracted from FTIR spectroscopy. For this reason, bone marrow stem cells (BMSCs) were differentiated to primordial germ cells (PGCs). Changes in cellular macromolecules in the time of 0, 24, 48, 72, and 96 h of differentiation, as different steps of the differentiation procedure were investigated by using FTIR spectroscopy. Also, the expression of pluripotency (Oct-4, Nanog and c-Myc) and specific genes (Mvh, Stella and Fragilis) were investigated by real-time PCR. However, the expression of genes in five steps of differentiation was predicted by FTIR spectroscopy. FTIR spectra showed changes in the template of band intensities at different differentiation steps. There are increasing changes in the stepwise differentiation procedure for the ratio area of CH2, which is symmetric to CH2 asymmetric stretching. An ensemble of expert methods, including regression tree (RT), boosting algorithm (BA), and generalized regression neural network (GRNN), was the best method to predict the gene expression by FTIR spectroscopy. In conclusion, the model was able to distinguish the pattern of different steps from cell differentiation by using some useful features extracted from FTIR spectra.

  16. In vivo soft tissue differentiation by diffuse reflectance spectroscopy: preliminary results

    Science.gov (United States)

    Zam, Azhar; Stelzle, Florian; Tangermann-Gerk, Katja; Adler, Werner; Nkenke, Emeka; Neukam, Friedrich Wilhelm; Schmidt, Michael; Douplik, Alexandre

    Remote laser surgery does not provide haptic feedback to operate layer by layer and preserve vulnerable anatomical structures like nerve tissue or blood vessels. The aim of this study is identification of soft tissue in vivo by diffuse reflectance spectroscopy to set the base for a feedback control system to enhance nerve preservation in oral and maxillofacial laser surgery. Various soft tissues can be identified by diffuse reflectance spectroscopy in vivo. The results may set the base for a feedback system to prevent nerve damage during oral and maxillofacial laser surgery.

  17. Differentiation between healthy thyroid remnants and tumor tissue after radioiodine therapy in patients with differentiated thyroid carcinoma using in-vitro phosphorus-31 magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Moka, D.; Dietlein, M.; Schicha, H.; Raffelt, K.; Hahn, J.

    2002-01-01

    Full text: In many tumors, tumor growth and spread is triggered by changes in cell membrane metabolism, which can lead to systemic alterations in levels of phospholipids. The aim of this study was to differentiate between healthy remnants of thyroid tissue and residual/recurrent tumor tissue or metastases in patients with thyroid carcinoma by measurement of plasma levels of various phospholipids. Phospholipid concentrations was measured by in-vitro phosphorus-31-magnetic resonance spectroscopy ( 31 P-MRS) in blood samples from 30 patients with thyroid cancer, who had been rendered hypothyroid in preparation for diagnostic/therapeutic administration of iodine-131. All patients were already thyroidectomized. 131 I-whole-body scintigraphy and measurements of thyroglobulin values in a 2-year-follow-up were used to distinguish between patients in remission, patients with only healthy thyroid remnants and patients with cancerous thyroid tissue and/or metastases. Significantly lower blood plasma levels of systemic sphingomyelin (0.33±0.06 vs. 0.46±0.03 (controls) mmol/l; p 31 P-MRS can be used to differentiate between the presence of tumor tissue, healthy remnants of thyroid tissue not requiring further treatment and remission in patients with thyroid cancer. In future, therefore, plasma 31 P-MRS could be developed as an additional diagnostic tool for the follow-up of differentiated thyroid cancer. (author)

  18. Mechanistic insights into the reduction of carbon dioxide on tin and bismuth electrodes using in situ infrared spectroscopy and differential electrochemical mass spectrometry

    Science.gov (United States)

    Baruch, Maor F.

    The factors that govern the electrochemical reduction of CO2 on Sn and Bi electrodes were studied. Chapter 1 discusses the relevant literature, the merits of reducing CO2 electrochemically, the ways in which CO2 reduction systems are characterized, and the outstanding challenges. Chapter 2 describes the design and construction of a differential electrochemical mass spectrometry (DEMS) system that can be used to probe the products of electrochemical reactions in situ and in real time. In Chapter 3, the role of surface oxides and hydroxides in the reduction of CO2 on Sn electrodes is discussed. in situ attenuated total reflectance infrared (ATR-IR) spectroscopy is the main analytical technique by which the system was studied. Peaks that are attributed to a surface-bound Sn carbonate are present under conditions that are suitable for CO2 reduction. A strong correlation between the presence of these peaks and catalytic activity exists with respect to the applied potential, the pH of the electrolyte, and the surface condition of the electrode. X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and electrochemical analysis were also used characterize the catalysts. Based on these data, a mechanism for the reduction of CO2 on Sn cathodes is proposed. The roles of morphology and surface oxide presence in the reduction of CO2 on Bi cathodes are discussed in Chapter 4. ATR-IR spectroscopy, XPS, EDX, SEM, cyclic voltammetry, and preparative electrolysis are used to demonstrate that, unlike Sn, Bi electrodes do not possess oxide-dependent catalytic behavior. Instead, it is shown that Bi electrodes are highly sensitive to morphological changes in surface structure, and that surface roughness is detrimental to HCOO-- production from CO2. Finally, it is shown that oxide-derived Bi, formed by the in situ reduction of Bi2O3 nanoparticles at cathodic potentials, can reduce CO2 to HCOO-- at near unit efficiencies at

  19. Characterization and differentiation of kaolins from selected Czech deposits using infrared spectroscopy and thermal analysis

    Czech Academy of Sciences Publication Activity Database

    Vaculíková, Lenka; Plevová, Eva

    2007-01-01

    Roč. 3, č. 1 (2007), s. 181-181 ISSN 1336-7242. [Zjazd chemikov /59./. 02.09.2007-06.09.2007, Tatranské Matliare] Institutional research plan: CEZ:AV0Z30860518 Keywords : kaolinite * infrared spectroscopy * thermal analysis (TG/DTA) Subject RIV: CB - Analytical Chemistry, Separation

  20. Chemically-specific dual/differential CARS micro-spectroscopy of saturated and unsaturated lipid droplets

    NARCIS (Netherlands)

    Di Napoli, C.; Masia, F; Pope, I.; Otto, Cornelis; Langbein, W.; Borri, P.

    2014-01-01

    We have investigated the ability of dual-frequency Coherent Antistokes Raman Scattering (D-CARS) micro-spectroscopy, based on femtosecond pulses (100 fs or 5 fs) spectrally focussed by glass dispersion, to distinguish the chemical composition of micron-sized lipid droplets consisting of different

  1. Resolving powers of >7900 using linked scans: how well does resolving power describe the separation capability of differential ion mobility spectrometry.

    Science.gov (United States)

    Santiago, Brandon G; Harris, Rachel A; Isenberg, Samantha L; Glish, Gary L

    2015-10-21

    Differential ion mobility spectrometry (DIMS) separations are described using similar terminology to liquid chromatography, capillary electrophoresis, and drift tube ion mobility spectrometry. The characterization and comparison of all these separations are typically explained in terms of resolving power, resolution, and/or peak capacity. A major difference between these separations is that DIMS separations are in space whereas the others are separations in time. However, whereas separations in time can, in theory, be extended infinitely, separations in space, such as DIMS separations, are constrained by the physical dimensions of the device. One method to increase resolving power of DIMS separations is to use helium in the DIMS carrier gas. However, ions have a greater mobility in helium which causes more ions to be neutralized due to collisions with the DIMS electrodes or electrode housing, i.e. the space constraints. This neutralization of ions can lead to the loss of an entire peak, or peaks, from a DIMS scan. To take advantage of the benefits of helium use while reducing ion losses, linked scans were developed. During a linked scan the amount of helium present in the DIMS carrier gas is decreased as the compensation field is increased. A comparison of linked scans to compensation field scans with constant helium is presented herein. Resolving powers >7900 are obtained with linked scans. However, this result highlights the limitation of using resolving power as a metric to describe DIMS separations.

  2. Malignant pleural mesothelioma with heterologous osteoblastic differentiation: case report of the characteristic CT and bone scan findings

    International Nuclear Information System (INIS)

    Cho, Young Jun; Kim, Joung Sook; Kim, Ji Young; Choi, Soo Jeon; Choi, Sang Bong

    2008-01-01

    Malignant pleural mesothelioma is an uncommon neoplasm which is accompanied extremely rarely by osteoblastic heterologous elements. The CT manifestations of this tumor have been reported in several references. And, to our knowledge, only one case report provides a description of the bone scan findings. Here, we report the case of a rapidly progressing malignant pleural mesothelioma with heterologous osteoblastic elements. A CT scan reveals diffuse irregular pleural thickening and very coarse nodular calcifications along the right pleura and major fissure. A bone scan revealed an area of extensive increased radioactivity consistent with the pleural calcifications on the CT scan in the right hemithorax. A follow-up CT scan performed 40 days later suggests the presence of rapidly progressing nodular coarse calcifications

  3. Malignant pleural mesothelioma with heterologous osteoblastic differentiation: case report of the characteristic CT and bone scan findings

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Jun; Kim, Joung Sook; Kim, Ji Young; Choi, Soo Jeon; Choi, Sang Bong [Sanggye Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of)

    2008-06-15

    Malignant pleural mesothelioma is an uncommon neoplasm which is accompanied extremely rarely by osteoblastic heterologous elements. The CT manifestations of this tumor have been reported in several references. And, to our knowledge, only one case report provides a description of the bone scan findings. Here, we report the case of a rapidly progressing malignant pleural mesothelioma with heterologous osteoblastic elements. A CT scan reveals diffuse irregular pleural thickening and very coarse nodular calcifications along the right pleura and major fissure. A bone scan revealed an area of extensive increased radioactivity consistent with the pleural calcifications on the CT scan in the right hemithorax. A follow-up CT scan performed 40 days later suggests the presence of rapidly progressing nodular coarse calcifications.

  4. Correlation between Temperature-dependent Fatigue Resistance and Differential Scanning Calorimetry Analysis for 2 Contemporary Rotary Instruments.

    Science.gov (United States)

    Arias, Ana; Macorra, José C; Govindjee, Sanjay; Peters, Ove A

    2018-04-01

    The aim of this study was to assess differences in cyclic fatigue (CF) life of contemporary heat-treated nickel-titanium rotary instruments at room and body temperatures and to document corresponding phase transformations. Forty Hyflex EDM (H-EDM) files (Coltene, Cuyahoga Falls, OH [#25/.08, manufactured by electrical discharge machining]) and 40 TRUShape (TS) files (Dentsply Tulsa Dental Specialties, Tulsa, OK [#25/.06v, manufactured by grinding and shape setting]) were divided into 2 groups (n = 20) for CF resistance tests in a water bath either at room (22°C ± 0.5°C) or body temperature (37°C ± 0.5°C). Instruments were rotated in a simulated canal (angle = 60°, radius = 3 mm, and center of the curvature 5 mm from the tip) until fracture occurred. The motor was controlled by an electric circuit that was interrupted after instrument fracture. The mean half-life and beta and eta Weibull parameters were determined and compared. Two instruments of each brand were subjected to differential scanning calorimetry (DSC). While TS instruments lasted significantly longer at room temperature (mean life = 234.7 seconds; 95% confidence interval [CI], 209-263.6) than at body temperature (mean life = 83.2 seconds; 95% CI, 76-91.1), temperature did not affect H-EDM behavior (room temperature mean life = 725.4 seconds; 95% CI, 658.8-798.8 and body temperature mean life = 717.9 seconds; 95% CI, 636.8-809.3). H-EDM instruments significantly outlasted TS instruments at both temperatures. At body temperature, TS was predominantly austenitic, whereas H-EDM was martensitic or in R-phase. TS was in a mixed austenitic/martensitic phase at 22°C, whereas H-EDM was in the same state as at 37°C. H-EDM had a longer fatigue life than TS, which showed a marked decrease in fatigue life at body temperature; neither the life span nor the state of the microstructure in the DSC differed for H-EDM between room or body temperature. Copyright © 2017 American Association of

  5. Evaluation of Hydrate Inhibition Performance of Water-soluble Polymers using Torque Measurement and Differential Scanning Calorimeter

    International Nuclear Information System (INIS)

    Shin, Kyuchul; Park, Juwoon; Kim, Jakyung; Kim, Hyunho; Seo, Yutaek; Lee, Yohan; Seo, Yongwon

    2014-01-01

    In this work, hydrate inhibition performance of water-soluble polymers including pyrrolidone, caprolactam, acrylamide types were evaluated using torque measurement and high pressure differential scanning calorimeter (HP µ-DSC). The obtained experimental results suggest that the studied polymers represent the kinetic hydrate inhibition (KHI) performance. 0.5 wt% polyvinylcaprolactam (PVCap) solution shows the hydrate onset time of 34.4 min and subcooling temperature of 15.9 K, which is better KHI performance than that of pure water - hydrate onset time of 12.3 min and subcooling temperature of 6.0 K. 0.5 wt% polyvinylpyrrolidone (PVP) solution shows the hydrate onset time of 27.6 min and the subcooling temperature of 13.2 K while polyacrylamide-co-acrylic acid partial sodium salt (PAM-co-AA) solution shows less KHI performance than PVP solution at both 0.5 and 5.0 wt%. However, PAM-co-AA solution shows slow growth rate and low hydrate amount than PVCap. In addition to hydrate onset and growth condition, torque change with time was investigated as one of KHI evaluation methods. 0.5 wt% PVCap solution shows the lowest average torque of 6.4 N cm and 0.5 wt% PAM-co-AA solution shows the average torque of 7.2 N cm. For 0.5 wt% PVP solution, it increases 11.5 N cm and 5.0 wt% PAM-co-AA solution shows the maximum average torque of 13.4 N cm, which is similar to the average torque of pure water, 15.2 N cm. Judging from the experimental results obtained by both an autoclave and a HP µ-DSC, the PVCap solution shows the best performance among the KHIs in terms of delaying hydrate nucleation. From these results, it can be concluded that the torque change with time is useful to identify the flow ability of tested solution, and the further research on the inhibition of hydrate formation can be approached in various aspects using a HP µ-DSC

  6. Evaluation of Hydrate Inhibition Performance of Water-soluble Polymers using Torque Measurement and Differential Scanning Calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Kyuchul; Park, Juwoon; Kim, Jakyung; Kim, Hyunho; Seo, Yutaek [KAIST, Daejeon (Korea, Republic of); Lee, Yohan; Seo, Yongwon [UNIST, Ulsan (Korea, Republic of)

    2014-12-15

    In this work, hydrate inhibition performance of water-soluble polymers including pyrrolidone, caprolactam, acrylamide types were evaluated using torque measurement and high pressure differential scanning calorimeter (HP µ-DSC). The obtained experimental results suggest that the studied polymers represent the kinetic hydrate inhibition (KHI) performance. 0.5 wt% polyvinylcaprolactam (PVCap) solution shows the hydrate onset time of 34.4 min and subcooling temperature of 15.9 K, which is better KHI performance than that of pure water - hydrate onset time of 12.3 min and subcooling temperature of 6.0 K. 0.5 wt% polyvinylpyrrolidone (PVP) solution shows the hydrate onset time of 27.6 min and the subcooling temperature of 13.2 K while polyacrylamide-co-acrylic acid partial sodium salt (PAM-co-AA) solution shows less KHI performance than PVP solution at both 0.5 and 5.0 wt%. However, PAM-co-AA solution shows slow growth rate and low hydrate amount than PVCap. In addition to hydrate onset and growth condition, torque change with time was investigated as one of KHI evaluation methods. 0.5 wt% PVCap solution shows the lowest average torque of 6.4 N cm and 0.5 wt% PAM-co-AA solution shows the average torque of 7.2 N cm. For 0.5 wt% PVP solution, it increases 11.5 N cm and 5.0 wt% PAM-co-AA solution shows the maximum average torque of 13.4 N cm, which is similar to the average torque of pure water, 15.2 N cm. Judging from the experimental results obtained by both an autoclave and a HP µ-DSC, the PVCap solution shows the best performance among the KHIs in terms of delaying hydrate nucleation. From these results, it can be concluded that the torque change with time is useful to identify the flow ability of tested solution, and the further research on the inhibition of hydrate formation can be approached in various aspects using a HP µ-DSC.

  7. [Velvet worm taxonomy from Santander, Colombia and thermogravimetry, differential scanning calorimetry and infrared spectroscopy of the adhesive secretion (Onychophora: Peripatidae)].

    Science.gov (United States)

    Jerez-Jaimes, Javier H; Bernal-Pérez, M Catalina

    2009-09-01

    Onychophoran worms are terrestrial organisms that have changed relatively little since the mid-Cambrian. We collected Macroperipatus geagy in coffee plantations at "Hacienda El Roble", Santander, Colombia, and here redescribe the species based on 15 individuals. A digital three-dimensional reconstruction of the ventral side of the body indicates that the primary and accessory papillae lack a defined distribution pattern. Diagnostic characters: one main tooth and one accessory tooth in the outer jaw, and one main tooth, one accessory tooth and seven denticles in the internal jaw. length (X=45.66 mm; SD=26.10), weight (X=0.95 g; SD=2.21) and number of lobopods (X=28.13 pairs; SD=1.30). We present a taxonomic key for six species of Macroperipatus. The liquid adhesive secretion lost 60% of the initial weight at 70 degrees C (solid: 13% close to 90 degrees C). The stability phase of the liquid secretion was within 90-280 degrees C (100 degrees C - 205 degrees C in the solid secretion). The starting degradation temperature of the sample was 355 degrees C. Heat flow changes in the solid and liquid secretions were confirmed by the sample behavior during thermogravimetric analysis. The percentage of beta sheets calculated by infrared spectrum was 59%. In comparison with Nephila spiders, the onychophoran secretion lost more weight and entered the phase of degradation at lower temperatures. This secondary structure of proteins gives the onychophoran adhesive secretion a tensile strength and extensibility similar to those of the silk produced by spiders for prey-capture.

  8. Lateral homogeneity of the electronic properties in pristine and ion-irradiated graphene probed by scanning capacitance spectroscopy

    Directory of Open Access Journals (Sweden)

    Giannazzo Filippo

    2011-01-01

    Full Text Available Abstract In this article, a scanning probe method based on nanoscale capacitance measurements was used to investigate the lateral homogeneity of the electron mean free path both in pristine and ion-irradiated graphene. The local variations in the electronic transport properties were explained taking into account the scattering of electrons by charged impurities and point defects (vacancies. Electron mean free path is mainly limited by charged impurities in unirradiated graphene, whereas an important role is played by lattice vacancies after irradiation. The local density of the charged impurities and vacancies were determined for different irradiated ion fluences.

  9. Inductively coupled plasma-atomic emission spectroscopy: a computer controlled, scanning monochromator system for the rapid determination of the elements

    Energy Technology Data Exchange (ETDEWEB)

    Floyd, M.A.

    1980-03-01

    A computer controlled, scanning monochromator system specifically designed for the rapid, sequential determination of the elements is described. The monochromator is combined with an inductively coupled plasma excitation source so that elements at major, minor, trace, and ultratrace levels may be determined, in sequence, without changing experimental parameters other than the spectral line observed. A number of distinctive features not found in previously described versions are incorporated into the system here described. Performance characteristics of the entire system and several analytical applications are discussed.

  10. Formation of chlorination by-products in waters with low SUVA--correlations with SUVA and differential UV spectroscopy.

    Science.gov (United States)

    Ates, Nuray; Kitis, Mehmet; Yetis, Ulku

    2007-10-01

    The formation of THMs and HAAs after chlorination of bulk water fractions of low-SUVA (specific UV absorbance) surface waters was investigated, and the applicability of SUVA and differential UV spectroscopy for monitoring THMs and HAAs in such waters was evaluated. Samples from two reservoirs were fractionated employing XAD-8, XAD-4, MIEX resin and granular activated carbon adsorption. A total of 83 bulk water NOM fractions (i.e., the remaining solutions after contact with the adsorbent or resin at various doses) were obtained and chlorinated. The majority of NOM in both waters was found to have average molecular weights <2000 Da and SUVA values <2L/mg Cm, indicating that NOM in the tested waters contained dominantly lower molecular weight fractions and low aromaticity. SUVA did not correlate well with the formation and speciation of THMs and HAAs, suggesting that SUVA does not capture the reactive sites on NOM moieties responsible for DBP formation in low-SUVA waters. Similarly, no correlations were found among THMs/HAAs formations and differential UV spectroscopy, indicating the formation of DBPs independent of destruction in UV-absorbing sites. In all fractions, concentrations of THMs were higher than those of HAAs. Chlorinated DBP species were dominant over brominated ones due to low bromide concentrations. The results overall suggested that low- or non-UV-absorbing NOM moieties play important roles in the formation of DBPs in waters with low SUVA, low DOC and low bromide levels.

  11. Elemental analysis of sunflower cataract in Wilson's disease: a study using scanning transmission electron microscopy and energy dispersive spectroscopy.

    Science.gov (United States)

    Jang, Hyo Ju; Kim, Joon Mo; Choi, Chul Young

    2014-04-01

    Signature ophthalmic characteristics of Wilson's disease (WD) are regarded as diagnostically important manifestations of the disease. Previous studies have proved the common occurrence of copper accumulation in the liver of patients with WD. However, in the case of sunflower cataracts, one of the rare diagnostic signs of WD, no study has demonstrated copper accumulation in the lens capsules of sunflower cataracts in WD patients. To investigate the nanostructure and elemental composition of sunflower cataracts in WD, transmission electron microscopy (TEM) was done on the capsulorhexised anterior lens capsule of sunflower cataracts in WD in order to evaluate anatomical variation and elemental changes. We utilized energy dispersive X-ray spectroscopy (EDS) to investigate the elemental composition of the lens capsule using both point and mapping spectroscopy. Quantitative analysis was performed for relative comparison of the elements. TEM showed the presence of granular deposits of varying size (20-350 nm), appearing mainly in the posterior one third of the anterior capsule. The deposits appeared in linear patterns with scattered dots. There were no electron-dense particles in the epithelial cell layer of the lens. Copper and sulfur peaks were consistently revealed in electron-dense granular deposits. In contrast, copper and sulfur peaks were absent in other tissues, including granule-free lens capsules and epithelial tissue. Most copper was exclusively located in clusters of electron-dense particles, and the copper distribution overlapped with sulfur on mapping spectroscopy. Quantitative analysis presented inconsistent ratios of copper to sulfur in each electron-dense granule. The mean ratio of copper to sulfur was about 3.25 (with a range of 2.39-3.78). This is the first elemental analysis of single electron particles in sunflower cataracts using EDS in the ophthalmic area. Sunflower cataracts with WD are assumed to be the result of accumulation of heterogeneous

  12. Utility of FDG-PETCT and magnetic resonance spectroscopy in differentiating between cerebral lymphoma and non-malignant CNS lesions in HIV-infected patients

    Energy Technology Data Exchange (ETDEWEB)

    Westwood, Thomas D., E-mail: tdwestwood@googlemail.com [Department of Radiology, The Christie NHS Foundation Trust, Wilmslow Road, Manchester (United Kingdom); Hogan, Celia, E-mail: celiahogan@hotmail.com [Monsall Unit, Department of Infectious Diseases and Tropical Medicine, North Manchester General Hospital, Pennine Acute Hospitals NHS Trust (United Kingdom); Julyan, Peter J., E-mail: Peter.Julyan@christie.nhs.uk [Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Wilmslow Road, Manchester (United Kingdom); Coutts, Glyn, E-mail: Glyn.Coutts@christie.nhs.uk [Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Wilmslow Road, Manchester (United Kingdom); Bonington, Suzie, E-mail: suzi.bonington@christie.nhs.uk [Department of Radiology, The Christie NHS Foundation Trust, Wilmslow Road, Manchester (United Kingdom); Carrington, Bernadette, E-mail: Bernadette.Carrington@christie.nhs.uk [Department of Radiology, The Christie NHS Foundation Trust, Wilmslow Road, Manchester (United Kingdom); Taylor, Ben, E-mail: Ben.taylor@christie.nhs.uk [Department of Radiology, The Christie NHS Foundation Trust, Wilmslow Road, Manchester (United Kingdom); Khoo, Saye, E-mail: S.H.Khoo@liverpool.ac.uk [Department of Infectious Diseases and Tropical Medicine, Royal Liverpool Hospital, Liverpool (United Kingdom); Bonington, Alec, E-mail: Alec.Bonington@pat.nhs.uk [Monsall Unit, Department of Infectious Diseases and Tropical Medicine, North Manchester General Hospital, Pennine Acute Hospitals NHS Trust (United Kingdom)

    2013-08-15

    Background and purpose: In HIV infected patients, MRI cannot reliably differentiate between central nervous system (CNS) lymphoma and non-malignant CNS lesions, particularly cerebral toxoplasmosis (CTOX). This study prospectively investigates the utility of FDG PET-CT and magnetic resonance spectroscopy (MRS) in discriminating CNS lymphoma from non-malignant CNS lesions in HIV infected patients, and assesses the ability of FDG PET-CT to guide the use of early brain biopsy. Methods: 10 HIV patients with neurological symptoms and contrast enhancing lesions on MRI were commenced on anti-toxoplasmosis therapy before undergoing FDG PET-CT and MRS. Brain biopsies were sought in those with FDG PET-CT suggestive of CNS lymphoma, and in those with a negative FDG PET-CT scan who failed to respond to therapy. Final diagnosis was based on histology or treatment response. Results: Two patients were confirmed to have CNS lymphoma and FDG PET-CT was consistent with this diagnosis in both. Six patients had cerebral toxoplasmosis in all of whom FDG PET-CT was consistent with non-malignant disease. One patient had progressive multifocal leukoencephalopathy (PML), FDG PET-CT was equivocal. One patient had a haemorrhagic brain metastasis and FDG PET-CT wrongly suggested non-malignant disease. MRS was performed successfully in eight subjects: three results were suggestive of CNS lymphoma (one true positive, two false positive), four suggested CTOX (two false negative, two true negative), one scan was equivocal. Conclusion: FDG PET-CT correctly identified all cases of CNS lymphoma and CTOX, supporting its use in this situation. MRS was unhelpful in our cohort.

  13. Utility of FDG-PETCT and magnetic resonance spectroscopy in differentiating between cerebral lymphoma and non-malignant CNS lesions in HIV-infected patients

    International Nuclear Information System (INIS)

    Westwood, Thomas D.; Hogan, Celia; Julyan, Peter J.; Coutts, Glyn; Bonington, Suzie; Carrington, Bernadette; Taylor, Ben; Khoo, Saye; Bonington, Alec

    2013-01-01

    Background and purpose: In HIV infected patients, MRI cannot reliably differentiate between central nervous system (CNS) lymphoma and non-malignant CNS lesions, particularly cerebral toxoplasmosis (CTOX). This study prospectively investigates the utility of FDG PET-CT and magnetic resonance spectroscopy (MRS) in discriminating CNS lymphoma from non-malignant CNS lesions in HIV infected patients, and assesses the ability of FDG PET-CT to guide the use of early brain biopsy. Methods: 10 HIV patients with neurological symptoms and contrast enhancing lesions on MRI were commenced on anti-toxoplasmosis therapy before undergoing FDG PET-CT and MRS. Brain biopsies were sought in those with FDG PET-CT suggestive of CNS lymphoma, and in those with a negative FDG PET-CT scan who failed to respond to therapy. Final diagnosis was based on histology or treatment response. Results: Two patients were confirmed to have CNS lymphoma and FDG PET-CT was consistent with this diagnosis in both. Six patients had cerebral toxoplasmosis in all of whom FDG PET-CT was consistent with non-malignant disease. One patient had progressive multifocal leukoencephalopathy (PML), FDG PET-CT was equivocal. One patient had a haemorrhagic brain metastasis and FDG PET-CT wrongly suggested non-malignant disease. MRS was performed successfully in eight subjects: three results were suggestive of CNS lymphoma (one true positive, two false positive), four suggested CTOX (two false negative, two true negative), one scan was equivocal. Conclusion: FDG PET-CT correctly identified all cases of CNS lymphoma and CTOX, supporting its use in this situation. MRS was unhelpful in our cohort

  14. Differentiation of bacterial versus viral otitis media using a combined Raman scattering spectroscopy and low coherence interferometry probe (Conference Presentation)

    Science.gov (United States)

    Zhao, Youbo; Shelton, Ryan L.; Tu, Haohua; Nolan, Ryan M.; Monroy, Guillermo L.; Chaney, Eric J.; Boppart, Stephen A.

    2016-02-01

    Otitis media (OM) is a highly prevalent disease that can be caused by either a bacterial or viral infection. Because antibiotics are only effective against bacterial infections, blind use of antibiotics without definitive knowledge of the infectious agent, though commonly practiced, can lead to the problems of potential harmful side effects, wasteful misuse of medical resources, and the development of antimicrobial resistance. In this work, we investigate the feasibility of using a combined Raman scattering spectroscopy and low coherence interferometry (LCI) device to differentiate OM infections caused by viruses and bacteria and improve our diagnostic ability of OM. Raman spectroscopy, an established tool for molecular analysis of biological tissue, has been shown capable of identifying different bacterial species, although mostly based on fixed or dried sample cultures. LCI has been demonstrated recently as a promising tool for determining tympanic membrane (TM) thickness and the presence and thickness of middle-ear biofilm located behind the TM. We have developed a fiber-based ear insert that incorporates spatially-aligned Raman and LCI probes for point-of-care diagnosis of OM. As shown in human studies, the Raman probe provides molecular signatures of bacterial- and viral-infected OM and normal middle-ear cavities, and LCI helps to identify depth-resolved structural information as well as guide and monitor positioning of the Raman spectroscopy beam for relatively longer signal acquisition time. Differentiation of OM infections is determined by correlating in vivo Raman data collected from human subjects with the Raman features of different bacterial and viral species obtained from cultured samples.

  15. Differentiation between Staphylococcus aureus and Staphylococcus epidermidis strains using Raman spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Rebrošová, K.; Šiler, Martin; Samek, Ota; Růžička, F.; Bernatová, Silvie; Ježek, Jan; Zemánek, Pavel; Holá, V.

    2017-01-01

    Roč. 12, č. 10 (2017), s. 881-890 ISSN 1746-0913 R&D Projects: GA ČR(CZ) GA15-20645S; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : Raman spectroscopy * rapid diagnostics * Staphylococcus epidermidis * Staphyococcus aureus Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 3.374, year: 2016

  16. Raman spectroscopy differentiates between sensitive and resistant multiple myeloma cell lines

    Science.gov (United States)

    Franco, Domenico; Trusso, Sebastiano; Fazio, Enza; Allegra, Alessandro; Musolino, Caterina; Speciale, Antonio; Cimino, Francesco; Saija, Antonella; Neri, Fortunato; Nicolò, Marco S.; Guglielmino, Salvatore P. P.

    2017-12-01

    Current methods for identifying neoplastic cells and discerning them from their normal counterparts are often nonspecific and biologically perturbing. Here, we show that single-cell micro-Raman spectroscopy can be used to discriminate between resistant and sensitive multiple myeloma cell lines based on their highly reproducible biomolecular spectral signatures. In order to demonstrate robustness of the proposed approach, we used two different cell lines of multiple myeloma, namely MM.1S and U266B1, and their counterparts MM.1R and U266/BTZ-R subtypes, resistant to dexamethasone and bortezomib, respectively. Then, micro-Raman spectroscopy provides an easily accurate and noninvasive method for cancer detection for both research and clinical environments. Characteristic peaks, mostly due to different DNA/RNA ratio, nucleic acids, lipids and protein concentrations, allow for discerning the sensitive and resistant subtypes. We also explored principal component analysis (PCA) for resistant cell identification and classification. Sensitive and resistant cells form distinct clusters that can be defined using just two principal components. The identification of drug-resistant cells by confocal micro-Raman spectroscopy is thus proposed as a clinical tool to assess the development of resistance to glucocorticoids and proteasome inhibitors in myeloma cells.

  17. Synchrotron radiation based cross-sectional scanning photoelectron microscopy and spectroscopy of n-ZnO:Al/p-GaN:Mg heterojunction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kai-Hsuan; Chen, Chia-Hao [Nano Science Group, National Synchrotron Radiation Research Center, Hsin-Ann Rd. 101, 30076 Hsinchu, Taiwan (China); Chang, Ping-Chuan [Department of Electro-Optical Engineering, Kun Shan University, Dawan Rd. 949, 71003 Tainan, Taiwan (China); Chen, Tse-Pu; Chang, Sheng-Po; Chang, Shoou-Jinn [Institute of Microelectronics and Department of Electrical Engineering, Center for Micro/Nano Science and Technology, Advanced Optoelectronic Technology Center, National Cheng Kung University, University Rd. 1, 70101 Tainan, Taiwan (China); Shiu, Hung-Wei; Chang, Lo-Yueh [Nano Science Group, National Synchrotron Radiation Research Center, Hsin-Ann Rd. 101, 30076 Hsinchu, Taiwan (China); Department of Physics, National Tsing Hua University, Kuang-Fu Rd. 101, 30013 Hsinchu, Taiwan (China)

    2013-02-18

    Al-doped ZnO (AZO) deposited by radio frequency co-sputtering is formed on epitaxial Mg-doped GaN template at room temperature to achieve n-AZO/p-GaN heterojunction. Alignment of AZO and GaN bands is investigated using synchrotron radiation based cross-sectional scanning photoelectron microscopy and spectroscopy on the nonpolar side-facet of a vertically c-axis aligned heterostructure. It shows type-II band configuration with valence band offset of 1.63 {+-} 0.1 eV and conduction band offset of 1.61 {+-} 0.1 eV, respectively. Rectification behavior is clearly observed, with a ratio of forward-to-reverse current up to six orders of magnitude when the bias is applied across the p-n junction.

  18. Supervised Mineral Classification with Semi-automatic Training and Validation Set Generation in Scanning Electron Microscope Energy Dispersive Spectroscopy Images of Thin Sections

    DEFF Research Database (Denmark)

    Flesche, Harald; Nielsen, Allan Aasbjerg; Larsen, Rasmus

    2000-01-01

    This paper addresses the problem of classifying minerals common in siliciclastic and carbonate rocks. Twelve chemical elements are mapped from thin sections by energy dispersive spectroscopy in a scanning electron microscope (SEM). Extensions to traditional multivariate statistical methods...... are applied to perform the classification. First, training and validation sets are grown from one or a few seed points by a method that ensures spatial and spectral closeness of observations. Spectral closeness is obtained by excluding observations that have high Mahalanobis distances to the training class......–Matusita distance and the posterior probability of a class mean being classified as another class. Fourth, the actual classification is carried out based on four supervised classifiers all assuming multinormal distributions: simple quadratic, a contextual quadratic, and two hierarchical quadratic classifiers...

  19. Investigation of the SiO2/Si(1 0 0) interface structure by means of angle-scanned photoelectron spectroscopy and diffraction

    International Nuclear Information System (INIS)

    Dreiner, S.; Schuermann, M.; Westphal, C.

    2004-01-01

    The local environment of Si at the interface between a thermally grown SiO 2 film and Si(1 0 0) was studied by angle-scanned photoelectron spectroscopy and diffraction. Si 2p core-level spectra containing chemically shifted components were recorded. These components were deconvoluted by least squares fitting and assigned to different Si oxidation states. The angular dependence of the photoelectron intensity was obtained from the least squares fit results. A simple statistical model was developed to describe the population and depth distribution of the different suboxide species. Using a simple electron attenuation scheme we can simulate the photoemission polar angle dependence of the various Si oxidation states within the model. The fitting of these model curves to the experimental data results in parameters which indicate a Si-O-Si bridge-bonded interface structure

  20. Observation of Supermodulation in LaO0.5F0.5BiSe2 by Scanning Tunneling Microscopy and Spectroscopy

    Science.gov (United States)

    Demura, Satoshi; Ishida, Naoki; Fujisawa, Yuita; Sakata, Hideaki

    2017-11-01

    We observed the surface and electronic structure of single-crystal LaO0.5F0.5BiSe2 by scanning tunneling microscopy/spectroscopy at 4.2 K. A square lattice composed of Bi atoms was observed at a positive sample bias voltage for the surface prepared by cleavage. At a negative sample bias voltage, a stripe structure along the Bi-Bi directions was observed as in a previous report on NdO0.7F0.3BiS2. Furthermore, we observed a supermodulation along the diagonal directions with a period of about five times the lattice constant. This seems to be indicative of the structural instability of this system rather than the electronic instability attributed to a nesting picture.

  1. Analysis of molecular interaction using a pulse-induced ring-down compression ATR-DIRLD step-scan time resolved spectroscopy/2D-IR

    Science.gov (United States)

    Nishikawa, Yuji; Ito, Hiroto; Noda, Isao

    2018-03-01

    A rheo-optical method, based on pulsed compression ATR dynamic infrared linear dichroism (DIRLD) step scan time-resolved-FT-IR/2D-IR spectroscopy, is further improved. By inserting a tungsten carbide block with massive weight between a film sample and a piezo electric actuator, a ring-down response was successfully generated according to the inertial effect. The improved method is used to analyze molecular interactions in cellulose acetate propionate (CAP) films including tricresyl-phosphate (TCP), as compared with cellulose triacetate (CTA) films with the TCP case. The result suggests that the existence of molecular interaction among propionyl groups in the CAP, the TCP's Methyl, and phenyl rings, which is not observed in the CTA-TCP system.

  2. The influence of C{sub s}/C{sub c} correction in analytical imaging and spectroscopy in scanning and transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zaluzec, Nestor J., E-mail: zaluzec@microscopy.com

    2015-04-15

    Aberration correction in scanning/transmission electron microscopy (S/TEM) owes much to the efforts of a small dedicated group of innovators. Leading that frontier has been Prof. Harald Rose. To date his leadership and dynamic personality has spearheaded our ability to leave behind many of the limitations imposed by spherical aberration (C{sub s}) in high resolution phase contrast imaging. Following shortly behind, has been the development of chromatic aberration correction (C{sub c}) which augments those accomplishments. In this paper we will review and summarize how the combination of C{sub s}/C{sub c} technology enhances our ability to conduct hyperspectral imaging and spectroscopy in today's and future computationally mediated experiments in both thin as well as realistic specimens in vacuo and during in-situ/environmental experiments.

  3. DESORPTION OF Te CAPPING LAYER FROM ZnTe (100: AUGER SPECTROSCOPY, LOW-ENERGY ELECTRON DIFFRACTION AND SCANNING TUNNELING MICROSCOPY

    Directory of Open Access Journals (Sweden)

    K. K. Sossoe

    2016-01-01

    Full Text Available The influence of the annealing temperature to desorb a protective Te capping layer of the zinc telluride (ZnTe (100 surface was investigated. The surface reconstruction of the ZnTe (100 upon the removal of a Te capping layer grown by the molecular beam epitaxy was characterized by different methods. Auger spectroscopy brought out the chemical composition of the surface before and after annealing; the Low-energy electron diffraction (LEED gave information about the crystallographic structure. The surface crystallographic configurations of tellurium Te (c (2x2 and Te (c (2x1 are confirmed by scanning tunneling microscopy (STM. Such a study reveals a phase transition from a rich-Te to a poor-Te surface as the annealing temperature increases. 

  4. Structure, Mobility, and Composition of Transition Metal Catalyst Surfaces. High-Pressure Scanning Tunneling Microscopy and Ambient-Pressure X-ray Photoelectron Spectroscopy Studies

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Zhongwei [Univ. of California, Berkeley, CA (United States)

    2013-12-06

    Surface structure, mobility, and composition of transition metal catalysts were studied by high-pressure scanning tunneling microscopy (HP-STM) and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) at high gas pressures. HP-STM makes it possible to determine the atomic or molecular rearrangement at catalyst surfaces, particularly at the low-coordinated active surface sites. AP-XPS monitors changes in elemental composition and chemical states of catalysts in response to variations in gas environments. Stepped Pt and Cu single crystals, the hexagonally reconstructed Pt(100) single crystal, and Pt-based bimetallic nanoparticles with controlled size, shape and composition, were employed as the model catalysts for experiments in this thesis.

  5. Nanoscale coupling of photons to vibrational excitation of Ag nanoparticle 2D array studied by scanning tunneling microscope light emission spectroscopy.

    Science.gov (United States)

    Katano, Satoshi; Toma, Koji; Toma, Mana; Tamada, Kaoru; Uehara, Yoichi

    2010-11-28

    Scanning tunneling microscope light emission (STM-LE) spectroscopy has been utilized to elucidate the luminescence phenomena of Ag nanoparticles capped with myristate (myristate-capped AgNP) and 2-methyl-1-propanethiolate (C(4)S-capped AgNP) on the dodecanethiol-precovered Au substrate. The STM imaging revealed that myristate-capped AgNPs form an ordered hexagonal array whereas C(4)S-capped AgNPs show imperfect ordering, indicating that a shorter alkyl chain of C(4)S-capped AgNP is not sufficient to form rigid interdigitation. It should be noted that such a nanoparticle ordering affects the luminescence properties of the Ag nanoparticle. We found that the STM-LE is only detected from the Ag nanoparticles forming the two-dimensional superlattice. This indicates that the STM-LE of the Ag nanoparticle is radiated via the collective excitation of the local surface plasmon resonance (LSPR) spread over the Ag nanoparticles. Note that the STM-LE spectra of the Ag nanoparticles exhibit spike-like peaks superimposed on the broad light emission peak. Using Raman spectroscopy, we concluded that the spike-like structure appearing in the STM-LE spectra is associated with the vibrational excitation of the molecule embedded between Ag nanoparticles.

  6. Conjugating precision and acquisition time in a Doppler broadening regime by interleaved frequency-agile rapid-scanning cavity ring-down spectroscopy

    Science.gov (United States)

    Gotti, Riccardo; Gatti, Davide; Masłowski, Piotr; Lamperti, Marco; Belmonte, Michele; Laporta, Paolo; Marangoni, Marco

    2017-10-01

    We propose a novel approach to cavity-ring-down-spectroscopy (CRDS) in which spectra acquired with a frequency-agile rapid-scanning (FARS) scheme, i.e., with a laser sideband stepped across the modes of a high-finesse cavity, are interleaved with one another by a sub-millisecond readjustment of the cavity length. This brings to time acquisitions below 20 s for few-GHz-wide spectra composed of a very high number of spectral points, typically 3200. Thanks to the signal-to-noise ratio easily in excess of 10 000, each FARS-CRDS spectrum is shown to be sufficient to determine the line-centre frequency of a Doppler broadened line with a precision of 2 parts over 1011, thus very close to that of sub-Doppler regimes and in a few-seconds time scale. The referencing of the probe laser to a frequency comb provides absolute accuracy and long-term reproducibility to the spectrometer and makes it a powerful tool for precision spectroscopy and line-shape analysis. The experimental approach is discussed in detail together with experimental precision and accuracy tests on the (30 012) ← (00 001) P12e line of CO2 at ˜1.57 μm.

  7. High-speed assembly language (80386/80387) programming for laser spectra scan control and data acquisition providing improved resolution water vapor spectroscopy

    Science.gov (United States)

    Allen, Robert J.

    1988-01-01

    An assembly language program using the Intel 80386 CPU and 80387 math co-processor chips was written to increase the speed of data gathering and processing, and provide control of a scanning CW ring dye laser system. This laser system is used in high resolution (better than 0.001 cm-1) water vapor spectroscopy experiments. Laser beam power is sensed at the input and output of white cells and the output of a Fabry-Perot. The assembly language subroutine is called from Basic, acquires the data and performs various calculations at rates greater than 150 faster than could be performed by the higher level language. The width of output control pulses generated in assembly language are 3 to 4 microsecs as compared to 2 to 3.7 millisecs for those generated in Basic (about 500 to 1000 times faster). Included are a block diagram and brief description of the spectroscopy experiment, a flow diagram of the Basic and assembly language programs, listing of the programs, scope photographs of the computer generated 5-volt pulses used for control and timing analysis, and representative water spectrum curves obtained using these programs.

  8. Static magnetic Faraday rotation spectroscopy combined with a differential scheme for OH detection

    Science.gov (United States)

    Zhao, Weixiong; Deng, Lunhua; Qian, Xiaodong; Fang, Bo; Gai, Yanbo; Chen, Weidong; Gao, Xiaoming; Zhang, Weijun

    2015-04-01

    The hydroxyl (OH) radical plays a critical role in atmospheric chemistry due to its high reactivity with volatile organic compounds (VOCs) and other trace gaseous species. Because of its very short life time and very low concentration in the atmosphere, interference-free high sensitivity in-situ OH monitoring by laser spectroscopy represents a real challenge. Faraday rotation spectroscopy (FRS) relies on the particular magneto-optic effect observed for paramagnetic species, which makes it capable of enhancing the detection sensitivity and mitigation of spectral interferences from diamagnetic species in the atmosphere. When an AC magnetic field is used, the Zeeman splitting of the molecular absorption line (and thus the magnetic circular birefringence) is modulated. This provides an 'internal modulation' of the sample, which permits to suppress the external noise like interference fringes. An alternative FRS detection scheme is to use a static magnetic field (DC-field) associated with laser wavelength modulation to effectively modulate the Zeeman splitting of the absorption lines. In the DC field case, wavelength modulation of the laser frequency can provide excellent performance compared to most of the sensing systems based on direct absorption and wavelength modulation spectroscopy. The dimension of the DC solenoid is not limited by the resonant frequency of the RLC circuit, which makes large dimension solenoid coil achievable and the absorption base length could be further increased. By employing a combination of the environmental photochemical reactor or smog chamber with multipass absorption cell, one can lower the minimum detection limit for high accuracy atmospheric chemistry studies. In this paper, we report on the development of a DC field based FRS in conjunction with a balanced detection scheme for OH radical detection at 2.8 μm and the construction of OH chemistry research platform which combined a large dimension superconducting magnetic coil with the

  9. Raman spectroscopy differentiates squamous cell carcinoma (SCC) from normal skin following treatment with a high-powered CO2 laser.

    Science.gov (United States)

    Fox, Sara A; Shanblatt, Ashley A; Beckman, Hugh; Strasswimmer, John; Terentis, Andrew C

    2014-12-01

    The number of cases of non-melanoma skin cancer (NMSC), which include squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), continues to rise as the aging population grows. Mohs micrographic surgery has become the treatment of choice in many cases but is not always necessary or feasible. Ablation with a high-powered CO2 laser offers the advantage of highly precise, hemostatic tissue removal. However, confirmation of complete cancer removal following ablation is difficult. In this study we tested for the first time the feasibility of using Raman spectroscopy as an in situ diagnostic method to differentiate NMSC from normal tissue following partial ablation with a high-powered CO2 laser. Twenty-five tissue samples were obtained from eleven patients undergoing Mohs micrographic surgery to remove NMSC tumors. Laser treatment was performed with a SmartXide DOT Fractional CO2 Laser (DEKA Laser Technologies, Inc.) emitting a wavelength of 10.6 μm. Treatment levels ranged from 20 mJ to 1200 mJ total energy delivered per laser treatment spot (350 μm spot size). Raman spectra were collected from both untreated and CO2 laser-treated samples using a 785 nm diode laser. Principal Component Analysis (PCA) and Binary Logistic Regression (LR) were used to classify spectra as originating from either normal or NMSC tissue, and from treated or untreated tissue. Partial laser ablation did not adversely affect the ability of Raman spectroscopy to differentiate normal from cancerous residual tissue, with the spectral classification model correctly identifying SCC tissue with 95% sensitivity and 100% specificity following partial laser ablation, compared with 92% sensitivity and 60% selectivity for untreated NMSC tissue. The main biochemical difference identified between normal and NMSC tissue was high levels of collagen in the normal tissue, which was lacking in the NMSC tissue. The feasibility of a combined high-powered CO2 laser ablation, Raman diagnostic procedure for the

  10. Dual channel detection of ultra low concentration of bacteria in real time by scanning fluorescence correlation spectroscopy

    Science.gov (United States)

    Altamore, Ilaria; Lanzano, Luca; Gratton, Enrico

    2013-06-01

    We describe a novel method to detect very low concentrations of bacteria in water. Our device consists of a portable horizontal geometry small confocal microscope with large pinhole and a holder for cylindrical cuvettes containing the sample. Two motors provide fast rotational and slow vertical motion of the cuvette so the device looks like a simplified flow cytometer without flow. To achieve high sensitivity, the design has two detection channels. Bacteria are stained by two different nucleic acid dyes and excited with two different lasers. Data are analyzed with a correlation filter based on particle passage pattern recognition. The passage of a particle through the illumination volume is compared with a Gaussian pattern in both channels. The width of the Gaussian correlates with the time of passage of the particle so one particle is counted when the algorithm finds a match with a Gaussian in both channels. The concentration of particles in the sample is deduced from the total number of coincident hits and the total volume scanned. This portable setup provides higher sensitivity, low-cost advantage, and it can have a wide use ranging from clinical applications to pollution monitors and water and air quality control.

  11. Dual channel detection of ultra low concentration of bacteria in real time by scanning fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    Altamore, Ilaria; Lanzano, Luca; Gratton, Enrico

    2013-01-01

    We describe a novel method to detect very low concentrations of bacteria in water. Our device consists of a portable horizontal geometry small confocal microscope with large pinhole and a holder for cylindrical cuvettes containing the sample. Two motors provide fast rotational and slow vertical motion of the cuvette so the device looks like a simplified flow cytometer without flow. To achieve high sensitivity, the design has two detection channels. Bacteria are stained by two different nucleic acid dyes and excited with two different lasers. Data are analyzed with a correlation filter based on particle passage pattern recognition. The passage of a particle through the illumination volume is compared with a Gaussian pattern in both channels. The width of the Gaussian correlates with the time of passage of the particle so one particle is counted when the algorithm finds a match with a Gaussian in both channels. The concentration of particles in the sample is deduced from the total number of coincident hits and the total volume scanned. This portable setup provides higher sensitivity, low-cost advantage, and it can have a wide use ranging from clinical applications to pollution monitors and water and air quality control. (paper)

  12. Gadolinium released from MR contrast agents is deposited in brain tumors: in situ demonstration using scanning electron microscopy with energy dispersive X-ray spectroscopy

    International Nuclear Information System (INIS)

    Xia, Daniel; Davis, Richard L.; Crawford, Judith A.; Abraham, Jerrold L.

    2010-01-01

    Background: Gadolinium (Gd)-containing MRI contrast agents (GdCA) are widely used in studies of brain tumors, and a number of reports suggest that under certain conditions, such as renal failure, Gd may be released from GdCA into patient's tissues. Whether this may happen in abnormal tissues in the absence of renal failure has not been studied. Purpose: To test the hypothesis that the local retention of GdCA resulting from brain tumor-associated alterations in the blood-brain barrier (BBB) may result in the deposition of Gd released from the GdCA, depending on stability. Material and Methods: In this retrospective study, 30 selected brain tumor biopsies from 28 patients (taken before and after an institutional switch from a less stable to an intermediate stable GdCA) were searched for Gd-containing deposits using scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Relevant histories and laboratory results were obtained through institutional electronic records. Associations between the presence of deposits and other variables were tested for statistical significance using the two-tailed Fisher's exact test. Results: Insoluble deposits containing Gd associated with phosphorus and calcium were found in seven biopsies from five patients. These deposits were found in patients with estimated GFRs above 53 ml/min, and were detected more often in those receiving GdCA before the switch from a less stable to an intermediate stable GdCA (P = 0.04), and may be more frequent in patients receiving more than one contrast-enhanced MR scan (P = 0.15). Conclusion: Gd-containing deposits are present in brain tumors following contrast-enhanced MR scans in patients without severe renal disease. Further studies are needed to assess the clinical importance of the deposits we observed and to determine whether they are also found in other conditions that alter the integrity of the BBB

  13. Differentiation of Anatolian honey samples from different botanical origins by ATR-FTIR spectroscopy using multivariate analysis.

    Science.gov (United States)

    Gok, Seher; Severcan, Mete; Goormaghtigh, Erik; Kandemir, Irfan; Severcan, Feride

    2015-03-01

    Botanical origin of the nectar predominantly affects the chemical composition of honey. Analytical techniques used for reliable honey authentication are mostly time consuming and expensive. Additionally, they cannot provide 100% efficiency in accurate authentication. Therefore, alternatives for the determination of floral origin of honey need to be developed. This study aims to discriminate characteristic Anatolian honey samples from different botanical origins based on the differences in their molecular content, rather than giving numerical information about the constituents of samples. Another scope of the study is to differentiate inauthentic honey samples from the natural ones precisely. All samples were tested via unsupervised pattern recognition procedures like hierarchical clustering and Principal Component Analysis (PCA). Discrimination of sample groups was achieved successfully with hierarchical clustering over the spectral range of 1800-750 cm(-1) which suggests a good predictive capability of Fourier Transform Infrared (FTIR) spectroscopy and chemometry for the determination of honey floral source. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Wavelength Selection Method Based on Differential Evolution for Precise Quantitative Analysis Using Terahertz Time-Domain Spectroscopy.

    Science.gov (United States)

    Li, Zhi; Chen, Weidong; Lian, Feiyu; Ge, Hongyi; Guan, Aihong

    2017-12-01

    Quantitative analysis of component mixtures is an important application of terahertz time-domain spectroscopy (THz-TDS) and has attracted broad interest in recent research. Although the accuracy of quantitative analysis using THz-TDS is affected by a host of factors, wavelength selection from the sample's THz absorption spectrum is the most crucial component. The raw spectrum consists of signals from the sample and scattering and other random disturbances that can critically influence the quantitative accuracy. For precise quantitative analysis using THz-TDS, the signal from the sample needs to be retained while the scattering and other noise sources are eliminated. In this paper, a novel wavelength selection method based on differential evolution (DE) is investigated. By performing quantitative experiments on a series of binary amino acid mixtures using THz-TDS, we demonstrate the efficacy of the DE-based wavelength selection method, which yields an error rate below 5%.

  15. Diagnostic potential of near-infrared Raman spectroscopy in the stomach: differentiating dysplasia from normal tissue

    Science.gov (United States)

    Teh, S K; Zheng, W; Ho, K Y; Teh, M; Yeoh, K G; Huang, Z

    2008-01-01

    Raman spectroscopy is a molecular vibrational spectroscopic technique that is capable of optically probing the biomolecular changes associated with diseased transformation. The purpose of this study was to explore near-infrared (NIR) Raman spectroscopy for identifying dysplasia from normal gastric mucosa tissue. A rapid-acquisition dispersive-type NIR Raman system was utilised for tissue Raman spectroscopic measurements at 785 nm laser excitation. A total of 76 gastric tissue samples obtained from 44 patients who underwent endoscopy investigation or gastrectomy operation were used in this study. The histopathological examinations showed that 55 tissue specimens were normal and 21 were dysplasia. Both the empirical approach and multivariate statistical techniques, including principal components analysis (PCA), and linear discriminant analysis (LDA), together with the leave-one-sample-out cross-validation method, were employed to develop effective diagnostic algorithms for classification of Raman spectra between normal and dysplastic gastric tissues. High-quality Raman spectra in the range of 800–1800 cm−1 can be acquired from gastric tissue within 5 s. There are specific spectral differences in Raman spectra between normal and dysplasia tissue, particularly in the spectral ranges of 1200–1500 cm−1 and 1600–1800 cm−1, which contained signals related to amide III and amide I of proteins, CH3CH2 twisting of proteins/nucleic acids, and the C=C stretching mode of phospholipids, respectively. The empirical diagnostic algorithm based on the ratio of the Raman peak intensity at 875 cm−1 to the peak intensity at 1450 cm−1 gave the diagnostic sensitivity of 85.7% and specificity of 80.0%, whereas the diagnostic algorithms based on PCA-LDA yielded the diagnostic sensitivity of 95.2% and specificity 90.9% for separating dysplasia from normal gastric tissue. Receiver operating characteristic (ROC) curves further confirmed that the most effective

  16. Biochemical differentiation of mycelium and yeast forms of Paracoccidioides brasiliensis by Fourier transform infrared spectroscopy

    Science.gov (United States)

    Castilho, Maiara L.; Campos, Claudia B. L.; Matos, Tatiana G. F.; de Abreu, Geraldo M. A.; Martin, Airton A.; Raniero, Leandro

    2012-01-01

    Paracoccidioides brasiliensis the etiological agent of paracoccidioidomycosis, is a dimorphic fungus existing as mycelia in the environment (or at 25 °C in vitro) and as yeast cells in the human host (or at 37°C in vitro). The most prominent difference between both forms is probably the cell wall polysaccharide, being 1,3-β-glucan usually found in mycelia and 1,3-α-glucan found in yeasts, but a plethora of other differences have already been described. In this work, we performed a Fourier Transform Infrared Spectroscopy analysis to compare the yeast and mycelia forms of P. brasiliensis and found additional biochemical differences. The analysis of the spectra showed that differences were distributed in chemical bonds of proteins, lipids and carbohydrates.

  17. Can AFLP genome scans detect small islands of differentiation? The case of shell sculpture variation in the periwinkle Echinolittorina hawaiiensis.

    Science.gov (United States)

    Tice, K A; Carlon, D B

    2011-08-01

    Genome scans have identified candidate regions of the genome undergoing selection in a wide variety of organisms, yet have rarely been applied to broadly dispersing marine organisms experiencing divergent selection pressures, where high recombination rates can reduce the extent of linkage disequilibrium (LD) and the ability to detect genomic regions under selection. The broadly dispersing periwinkle Echinolittorina hawaiiensis exhibits a heritable shell sculpture polymorphism that is correlated with environmental variation. To elucidate the genetic basis of phenotypic variation, a genome scan using over 1000 AFLP loci was conducted on smooth and sculptured snails from divergent habitats at four replicate sites. Approximately 5% of loci were identified as outliers with Dfdist, whereas no outliers were identified by BayeScan. Closer examination of the Dfdist outliers supported the conclusion that these loci were false positives. These results highlight the importance of controlling for Type I error using multiple outlier detection approaches, multitest corrections and replicate population comparisons. Assuming shell phenotypes have a genetic basis, our failure to detect outliers suggests that the life history of the target species needs to be considered when designing a genome scan. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

  18. The orbits of the triple-star system 1 geminorum from phases differential astrometry and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Benjamin F. [The Charles Stark Draper Laboratory, Inc., 555 Technology Square, Cambridge, MA 02139 (United States); Muterspaugh, Matthew W. [Department of Mathematical Sciences, College of Engineering, Tennessee State University, Boswell Science Hall, Nashville, TN 37209 (United States); Griffin, R. F. [The Observatories, Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Scarfe, C. D. [Department of Physics and Astronomy, University of Victoria, BC V8W 3P6 (Canada); Fekel, Francis C.; Williamson, Michael H. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Boulevard, Box 9501, Nashville, TN 37209 (United States); Eaton, Joel A. [7050 Bakerville Road, Waverly, TN 37185 (United States); Shao, M.; Colavita, M. M. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Konacki, Maciej [Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Rabianska 8, 87-100 Torun (Poland)

    2014-03-01

    We have used precise differential astrometry from the Palomar High-precision Astrometric Search for Exoplanet Systems project and radial-velocity measurements covering a time span of 40 yr to determine the orbital parameters of the 1 Geminorum triple system. We present the first detection of the spectral lines of the third component of the system, together with precise mass (0.5%) and distance (0.15%) determinations for this system. In addition, our astrometry allows us to make the first determination of the mutual inclination of the orbits.

  19. Differentiation of osteomyelitis and infarction in sickle-cell hemoglobinopathies using combined bone-marrow and gallium scanning

    International Nuclear Information System (INIS)

    Hatfield, M.K.; Kahn, C.E.; Ryan, J.W.; Martin, W.B.

    1986-01-01

    The clinical records and scintigrams of patients with sickle cell hemoglobinopathies in whom acute symptoms developed suggestive of possible osteomyelitis and who had undergone sequential Tc-99m bone marrow scans and gallium scintigraphy of the affected sites were reviewed. Osteomyelitis was correctly diagnosed in six of 18 cases when gallium was focally increased relative to a site of decreased or absent bone marrow activity. Of 12 episodes of infarction, both studies showed focally decreased activity in a concordant manner in 11. The remaining, false-positive study indicated slightly increased gallium in 11. The remaining, false-positive indicated slightly increased gallium concentration at a site of decreased bone marrow activity. Overall, a protocol of sequential Tc-99m bone marrow scans and gallium scintigraphy is an effective means of distinguishing osteomyelitis from infarction in patients with sickle cell hemoglobinopathies

  20. Caffeine differentially alters cortical hemodynamic activity during working memory: a near infrared spectroscopy study.

    Science.gov (United States)

    Heilbronner, Urs; Hinrichs, Hermann; Heinze, Hans-Jochen; Zaehle, Tino

    2015-10-01

    Caffeine is a widely used stimulant with potentially beneficial effects on cognition as well as vasoconstrictive properties. In functional magnetic imaging research, caffeine has gained attention as a potential enhancer of the blood oxygenation level-dependent (BOLD) response. In order to clarify changes of oxy- and deoxyhemoglobin (HbO and HbR) induced by caffeine during a cognitive task, we investigated a working memory (WM) paradigm (visual 2-back) using near-infrared spectroscopy (NIRS). Behaviorally, caffeine had no effect on the WM performance but influenced reaction times in the 0-back condition. NIRS data demonstrate caffeine-dependent alterations of the course of the hemodynamic response. The intake of 200 mg caffeine caused a significant decrease of the HbO response between 20 and 40 s after the onset of a 2-back task in the bilateral inferior frontal cortex (IFC). In parallel, the HbR response of the left IFC was significantly increased due to caffeine intake. In line with previous results, we did not detect an effect of caffeine on most aspects of behavior. Effects of caffeine on brain vasculature were detected as general reduction of HbO. Neuronal effects of caffeine are reflected in an increased concentration of HbR in the left hemisphere when performing a verbal memory task and suggest influences on metabolism.

  1. Localized proton magnetic resonance spectroscopy of the brain differentiates the inborn metabolic encephalopathies in children

    Energy Technology Data Exchange (ETDEWEB)

    Chabrol, B.; Salvan, A.M.; Confort-Gouny, S.; Vion-Dury, J.; Cozzone, P.J. [Hopital de la Timone, 13 - Marseille (France)

    1995-09-01

    Localized brain proton magnetic resonance spectroscopy (MRS) has been performed using a STEAM (Stimulated echo-acquisition mode) method with a short-echo time (20ms) in 10 children suffering from different lysosomal diseases, 6 boys with X-linked adrenoleukodystrophy (X-ALD) and 5 healthy children. Metabolic data from localized spectra were processed by principal component analysis (PCA) of 7 metabolic variables recorded on the MR spectra. PCA allows to delineate different clusters corresponding to the 2 pathological groups which are separated from each other and from the control group. The position of each spectrum on the patient map correlates with the clinical data and to the evolution of the patients subjected to a follow-up. These results also confirm the metabolic features characterizing the pathologies of the lysosome (increase in inositol) and the peroxisome (increase in choline and free lipids). PCA constitutes an alternative to the classical statistical methods to analyze and compare metabolic modifications in small populations of patients and allows to identify the most critical parameters defining the organization of the pathological populations. This analysis clearly increases the discrimination among pathologies based on the metabolic profiles obtained by MRS. (author). 17 refs., 2 figs., 2 tabs.

  2. Ozone monitoring using differential optical absorption spectroscopy (DOAS) and UV photometry instruments in Sohar, Oman.

    Science.gov (United States)

    Nawahda, Amin

    2015-08-01

    Ground level ozone (O3) concentrations were measured across Sohar highway in Oman during a four-month period from September to December 2014 by using an open-path deferential optical absorption spectroscopy (DOAS) instrument. The monthly average concentrations of O3 varied from 19.6 to 29.4 ppb. The measurements of O3 are compared with the measurements of a non-open-path UV photometry analyzer (UVP). The percent difference (PD) concept and linear regression methods were used to compare the readings of the two instruments. The findings show high correlation coefficients between the measurements of the DOAS and UVP instruments. The DOAS measurements of O3 are found to be less than those measured by the UVP instrument; the correlation coefficients between absolute PD values and meteorological parameters and PM2.5 were very low indicating a minor effect; therefore, titrations of O3 by traffic emissions and difference in elevation could be the reason for the difference in the measurements of the two instruments.

  3. Evaluation of thermal stability of paraffin wax by differential scanning calorimetry; Avaliacao da estabilidade termica de parafina por calorimetria diferencial de varredura

    Energy Technology Data Exchange (ETDEWEB)

    Godinho, K.O.; Silva, A.G.P.; Holanda, J.N.F. [Universidade Estadual do Norte Fluminense (LAMAV/UENF), Campos dos Goytacazes, RJ (Brazil). Grupo de Materiais Ceramicos], Email: holanda@uenf.br

    2010-07-01

    Phase change materials for heat storage are used as passive solar energy storage materials, which can be impregnated into construction materials. In this work the thermal stability (heating/cooling cycle) of the paraffin wax was investigated using differential scanning calorimetry. The latent heat and fusion temperature were determined for the following thermal cycles: 0, 30, 180 and 360. The thermal stability for paraffin wax infiltrated in support of gypsum was also determined. The experimental results showed that the paraffin wax showed good thermal stability in the states pure and infiltrated for up to 360 thermal cycles. (author)

  4. Differentiating Pancreatic Ductal Adenocarcinoma from Pancreatic Serous Cystadenoma, Mucinous Cystadenoma, and a Pseudocyst with Detailed Analysis of Cystic Features on CT Scans: a Preliminary Study

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Peijie; Mahyoub, Radfan; Lin, Xiaozhu; Chen, Kemin; Chai, Weimin; Xie, Jing [Rui Jin Hospital Shanghai Jiao Tong University School of Medicine, Shanghai (China)

    2011-04-15

    To determine whether or not detailed cystic feature analysis on CT scans can assist in the differential diagnosis of pancreatic ductal adenocarcinoma (PDAC) from serous cystadenoma (SCN), mucinous cystadenoma (MCN), and a pseudocyst. This study received Institutional Review Board approval and informed patient consent was waived. Electronic radiology and pathology databases were searched to identify patients with PDAC (n = 19), SCN (n = 26), MCN (n = 20) and a pseudocyst (n = 23) who underwent pancreatic CT imaging. The number, size, location, and contents of cysts, and the contour of the lesions were reviewed, in addition to the wall thickness, enhancement patterns, and other signs of pancreatic and peripancreatic involvement. Diagnosis was based on lesion resection (n = 82) or on a combination of cytological findings, biochemical markers, and tumor markers (n = 6). Fisher's exact test was used to analyze the results. A combination of the CT findings including irregular contour, multiple cysts, mural nodes, and localized thickening, had a relatively high sensitivity (74%) and specificity (75%) for differentiating PDAC from SCN, MCN, and pseudocysts (p < 0.05). Other CT findings such as location, greatest dimension, or the presence of calcification were not significantly different. The CT findings for PDAC are non-specific, but perhaps helpful for differentiation. PDAC should be included in the general differential diagnosis of pancreatic cystic neoplasms

  5. Magnetic resonance spectroscopy detects differential lipid composition in mammary glands on low fat, high animal fat versus high fructose diets.

    Directory of Open Access Journals (Sweden)

    Dianning He

    Full Text Available The effects of consumption of different diets on the fatty acid composition in the mammary glands of SV40 T-antigen (Tag transgenic mice, a well-established model of human triple-negative breast cancer, were investigated with magnetic resonance spectroscopy and spectroscopic imaging. Female C3(1 SV40 Tag transgenic mice (n = 12 were divided into three groups at 4 weeks of age: low fat diet (LFD, high animal fat diet (HAFD, and high fructose diet (HFruD. MRI scans of mammary glands were acquired with a 9.4 T scanner after 8 weeks on the diet. 1H spectra were acquired using point resolved spectroscopy (PRESS from two 1 mm3 boxes on each side of inguinal mammary gland with no cancers, lymph nodes, or lymph ducts. High spectral and spatial resolution (HiSS images were also acquired from nine 1-mm slices. A combination of Gaussian and Lorentzian functions was used to fit the spectra. The percentages of poly-unsaturated fatty acids (PUFA, mono-unsaturated fatty acids (MUFA, and saturated fatty acids (SFA were calculated from each fitted spectrum. Water and fat peak height images (maps were generated from HiSS data. The results showed that HAFD mice had significantly lower PUFA than both LFD (p < 0.001 and HFruD (p < 0.01 mice. The mammary lipid quantity calculated from 1H spectra was much larger in HAFD mice than in LFD (p = 0.03 but similar to HFruD mice (p = 0.10. The average fat signal intensity over the mammary glands calculated from HiSS fat maps was ~60% higher in HAFD mice than in LFD (p = 0.04 mice. The mean or median of calculated parameters for the HFruD mice were between those for LFD and HAFD mice. Therefore, PRESS spectroscopy and HiSS MRI demonstrated water and fat composition changes in mammary glands due to a Western diet, which was low in potassium, high in sodium, animal fat, and simple carbohydrates. Measurements of PUFA with MRI could be used to evaluate cancer risk, improve cancer detection and diagnosis, and guide preventative

  6. FTIR spectroscopy in medical mycology: applications to the differentiation and typing of Candida.

    Science.gov (United States)

    Toubas, Dominique; Essendoubi, Mohammed; Adt, Isabelle; Pinon, Jean-Michel; Manfait, Michel; Sockalingum, Ganesh D

    2007-03-01

    The incidence of fungal infections, in particular candidiasis and aspergillosis, has considerably increased during the last three decades. This is mainly due to advances in medical treatments and technologies. In high risk patients (e.g. in haematology or intensive care), the prognosis of invasive candidiasis is relatively poor. Therefore, a rapid and correct identification of the infectious agent is important for an efficient and prompt therapy. Most clinical laboratories rely on conventional identification methods that are based on morphological, physiological and nutritional characteristics. However, these have their limitations because they are time-consuming and not always very accurate. Moreover, molecular methods may be required to determine the genetic relationship between the infectious strains, for instance in Candida outbreaks. In addition, the latter methods require time, expensive consumables and highly trained staff to be performed adequately. In this study, we have applied the FTIR spectroscopic approach to different situations encountered in routine mycological diagnosis. We show the potentials of this phenotypic approach, used in parallel with routine identification methods, for the differentiation of 3 frequently encountered Candida species (C. albicans, C. glabrata and C. krusei) by using both suspensions and microcolonies. This approach, developed for an early discrimination, may help in the initial choice of antifungal treatment. Furthermore, we demonstrate the feasibility of the method for intraspecies comparison (typing) of 3 Candida species (C. albicans, C. glabrata and C. parapsilosis), particularly when an outbreak is suspected.

  7. Water vapor spectroscopy in the 815-nm wavelength region for Differential Absorption Lidar measurements

    Science.gov (United States)

    Ponsardin, Patrick; Browell, Edward V.

    1995-01-01

    The differential absorption lidar (DIAL) technique was first applied to the remote measurement of atmospheric water vapor profiles from airborne platforms in 1981. The successful interpretation of the lidar profiles relies strongly on an accurate knowledge of specific water vapor absorption line parameters: line strength, pressure broadening coefficient, pressure-induced shift coefficient and the respective temperature-dependence factors. NASA Langley Research Center has developed and is currently testing an autonomous airborne water vapor lidar system: LASE (Lidar Atmospheric Sensing Experiment). This DIAL system uses a Nd:YAG-pumped Ti:Sapphire laser seeded by a diode laser as a lidar transmitter. The tunable diode has been selected to operate in the 813-818 nm wavelength region. This 5-nm spectral interval offers a large distribution of strengths for temperature-insensitive water vapor absorption lines. In support of the LASE project, a series of spectroscopic measurements were conducted for the 16 absorption lines that have been identified for use in the LASE measurements. Prior to this work, the experimental data for this water vapor absorption band were limited - to our knowledge - to the line strengths and to the line positions.

  8. Genome-wide scan for signatures of human population differentiation and their relationship with natural selection, functional pathways and diseases.

    Directory of Open Access Journals (Sweden)

    Roberto Amato

    2009-11-01

    Full Text Available Genetic differences both between individuals and populations are studied for their evolutionary relevance and for their potential medical applications. Most of the genetic differentiation among populations are caused by random drift that should affect all loci across the genome in a similar manner. When a locus shows extraordinary high or low levels of population differentiation, this may be interpreted as evidence for natural selection. The most used measure of population differentiation was devised by Wright and is known as fixation index, or F(ST. We performed a genome-wide estimation of F(ST on about 4 millions of SNPs from HapMap project data. We demonstrated a heterogeneous distribution of F(ST values between autosomes and heterochromosomes. When we compared the F(ST values obtained in this study with another evolutionary measure obtained by comparative interspecific approach, we found that genes under positive selection appeared to show low levels of population differentiation. We applied a gene set approach, widely used for microarray data analysis, to detect functional pathways under selection. We found that one pathway related to antigen processing and presentation showed low levels of F(ST, while several pathways related to cell signalling, growth and morphogenesis showed high F(ST values. Finally, we detected a signature of selection within genes associated with human complex diseases. These results can help to identify which process occurred during human evolution and adaptation to different environments. They also support the hypothesis that common diseases could have a genetic background shaped by human evolution.

  9. Surface characterization of 7S and 11S globulin powders from soy protein examined by X-ray photoelectron spectroscopy and scanning electron microscopy.

    Science.gov (United States)

    Zhao, Xiaoyan; Chen, Jun; Zhu, Qingjun; Du, Fangling; Ao, Qiang; Liu, Jie

    2011-09-01

    In this study the surface composition of 7S and 11S globulin powders from soybean proteins by aqueous buffer and reverse micelle extractions had been examined using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Analysis by XPS revealed that the O and N atomic percentage of 7S and 11S globulin surfaces from bis(2-ethylhexyl) sodium sulfosuccinate (AOT) reverse micelle was higher than from aqueous buffer, but the C atomic percentage was lower. The O/C ratio of the 7S globulin powder from aqueous buffer and reverse micelle was similar while significant differences were obtained in the O/C ratio of the 11S globulin powder, N/C atom ratios of the 7S and 11S globulin powders and high-resolution XPS C 1s, N 1s, O 1s spectra. Powder microstructure after reverse micelle treatment showed the presence of small pores, indicating the effect of reverse micelle on the 7S and 11S globulin structure. The obtained results indicated that the reverse micelle could affect the C, O and N components on the surface of soybean proteins. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Scanning tunneling spectroscopy to probe site-selection in heterovalent doping: Zn(II)-doped Cu(I)In(III)S2 as a case study

    Science.gov (United States)

    Kundu, Biswajit; Pal, Amlan J.

    2017-08-01

    We report scanning tunneling spectroscopy (STS) of a heterovalent-doped ternary compound semiconductors and their binary counterparts. The effect of dopants in the semiconductors that yielded a shift in Fermi energy has been found to be manifested in the density of states (DOS) spectrum. The shift infers the nature of doping, which the heterovalent dopants induce, and hence the site of the ternary system that the dopants occupy. For example, in the present case with Zn(II)-doped Cu(I)In(III)S2, the DOS spectra showed a shift in Fermi energy towards the conduction band and hence a n-type doping due to the introduction of electrons. Such a shift inferred that the bivalent dopants occupied the cuprous site. The results have been substantiated by STS studies of doped binary components, namely, Cu2S and In2S3 and shift in Fermi energy thereof. With the tuning in the Fermi energy, the homojunctions between undoped and doped semiconductors have a type-II band-alignment at the interface resulting in current rectification through the junctions. The band-diagram of the homojunctions formed through STS substantiated the direction of current-rectification in the junctions.

  11. Morphological and chemical changes in dentin after using endodontic agents: Fourier transform Raman spectroscopy, energy-dispersive x-ray fluorescence spectrometry, and scanning electron microscopy study

    Science.gov (United States)

    Pascon, Fernanda Miori; Kantovitz, Kamila Rosamilia; Soares, Luís Eduardo Silva; Santo, Ana Maria do Espírito; Martin, Airton Abraha~o.; Puppin-Rontani, Regina Maria

    2012-07-01

    We examine the morphological and chemical changes in the pulp chamber dentin after using endodontic agents by scanning electron microscopy (SEM), Fourier transform Raman spectroscopy (FT-Raman), and micro energy-dispersive x-ray fluorescence spectrometry (μEDXRF). Thirty teeth were sectioned exposing the pulp chamber and divided by six groups (n=5): NT-no treatment; CHX-2% chlorhexidine; CHXE-2% chlorhexidine+17% EDTA E-17% EDTA; SH5-5.25% NaOCl; SH5E-5.25% NaOCl+17% EDTA. The inorganic and organic content was analyzed by FT-Raman. μEDXRF examined calcium (Ca) and phosphorus (P) content as well as Ca/P ratio. Impressions of specimens were evaluated by SEM. Data were submitted to Kruskal-Wallis and Dunn tests (pNT=SH5E>CHX>E>CHXE). CHXE and E presented the highest Ca/P ratio values compared to the other groups (p<0.05). The SEM images in the EDTA-treated groups had the highest number of open tubules. Erosion in the tubules was observed in CHX and SH5E groups. Endodontic agents change the inorganic and organic content of pulp chamber dentin. NaOCl used alone, or in association with EDTA, was the most effective agent considering chemical and morphological approaches.

  12. Characterization of the ashes from the 2014-2015 Turrialba Volcano eruptions by means of scanning electron microscopy and energy dispersive X-Ray spectroscopy

    International Nuclear Information System (INIS)

    Lucke, Oscar H.; Calderon, Ariadna

    2016-01-01

    The Turrialba Volcano is a stratovolcano located approximately 35 km northwest from San Jose, Costa Rica's capital city. A series of eruptions since October 29, 2014 until at least late 2015, has represented the most significant activity of this volcano since the 1860s. A significant volume of ash was dispersed with this eruptions that reached the most populous areas of the country. The characteristics of the ash particles are analyzed in order to establish the nature of the eruptive events that occurred on 2014 and 2015, and to monitor the evolution of the eruptive processes. The analysis was carried out utilizing optical microscopy and stereomicroscopy techniques, as well as novel scanning electron microscopy (SEM) methods that involve imaging and element composition analysis by means of Energy Dispersive X-Ray Spectroscopy (EDX). The evolution of the Turrialba eruptions is showed from phreatic events in 2014, with ashes composed entirely of non-juvenile fragments, to phreatomagmatic events starting on March 12, 2015 with the appearance of a significant fraction of juvenile components in the ash. (author)

  13. Measurement Error in Atomic-Scale Scanning Transmission Electron Microscopy—Energy-Dispersive X-Ray Spectroscopy (STEM-EDS) Mapping of a Model Oxide Interface

    Energy Technology Data Exchange (ETDEWEB)

    Spurgeon, Steven R.; Du, Yingge; Chambers, Scott A.

    2017-04-05

    Abstract

    With the development of affordable aberration correctors, analytical scanning transmission electron microscopy (STEM) studies of complex interfaces can now be conducted at high spatial resolution at laboratories worldwide. Energy-dispersive X-ray spectroscopy (EDS) in particular has grown in popularity, as it enables elemental mapping over a wide range of ionization energies. However, the interpretation of atomically resolved data is greatly complicated by beam–sample interactions that are often overlooked by novice users. Here we describe the practical factors—namely, sample thickness and the choice of ionization edge—that affect the quantification of a model perovskite oxide interface. Our measurements of the same sample, in regions of different thickness, indicate that interface profiles can vary by as much as 2–5 unit cells, depending on the spectral feature. This finding is supported by multislice simulations, which reveal that on-axis maps of even perfectly abrupt interfaces exhibit significant delocalization. Quantification of thicker samples is further complicated by channeling to heavier sites across the interface, as well as an increased signal background. We show that extreme care must be taken to prepare samples to minimize channeling effects and argue that it may not be possible to extract atomically resolved information from many chemical maps.

  14. Evaluation of the Forensic Utility of Scanning Electron Microscopy-Energy Dispersive Spectroscopy and Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry for Printing Ink Examinations.

    Science.gov (United States)

    Corzo, Ruthmara; Subedi, Kiran; Trejos, Tatiana; Almirall, José R

    2016-05-01

    Improvements in printing technology have exacerbated the problem of document counterfeiting, prompting the need for analytical techniques that better characterize inks for forensic analysis and comparisons. In this study, 319 printing inks (toner, inkjet, offset, and Intaglio) were analyzed directly on the paper substrate using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS). As anticipated, the high sensitivity of LA-ICP-MS pairwise comparisons resulted in excellent discrimination (average of ~ 99.6%) between different ink samples from each of the four ink types and almost 100% correct associations between ink samples known to originate from the same source. SEM-EDS analysis also resulted in very good discrimination for different toner and intaglio inks (>97%) and 100% correct association for samples from the same source. SEM-EDS provided complementary information to LA-ICP-MS for certain ink types but showed limited utility for the discrimination of inkjet and offset inks. © 2016 American Academy of Forensic Sciences.

  15. Si(111)-sq root 21 x sq root 21 -(Ag+Cs) surface studied by scanning tunneling microscopy and angle-resolved photoemission spectroscopy

    CERN Document Server

    Liu, C; Morikawa, H; Okino, H; Hasegawa, S; Okuda, T; Kinoshita, T

    2003-01-01

    Scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES) were used to study the atomic and electronic structures of the Si(111)-sq root 21 x sq root 21-(Ag + Cs) surface (sq root 21-Cs in short), which was induced by depositing caesium atoms on the Si(111)-sq root 3 x sq root 3-Ag surface at room temperature (RT). Compared with previously reported STM images of noble-metal induced sq root 21 x sq root 21 phases including the Si(111)-sq root 21 x sq root 21-(Ag+Ag) and Si(111)-sq root 21 x sq root 21-(Ag+Au) surfaces (sq root 21-Ag and sq root 21-Au, respectively), the sq root 21-Cs surface displayed quite different features in STM images. The ARPES data of the sq root 21-Cs surface revealed an intrinsic dispersive surface-state band, together with a non-dispersive one near the Fermi level, which was also different from those of the sq root 21-Ag and sq root 21-Au surfaces. These results strongly suggest different atomic arrangements between Cs- and noble-metal induced sq root ...

  16. Application of Scanning Electron Microscopy/Energy-Dispersive X-Ray Spectroscopy for Characterization of Detrital Minerals in Karst Cave Speleothems.

    Science.gov (United States)

    Zupančič, Nina; Miler, Miloš; Šebela, Stanka; Jarc, Simona

    2016-02-01

    Micro-scale observations in karst caves help to identify different processes that shaped local morphology. Scanning electron microscopy/energy-dispersive X-ray spectroscopy inspection of speleothems from two karst caves in Slovenia, Predjama and Črna Jama, confirmed the presence of sub-angular to sub-rounded detrital fragments of clay minerals, feldspars, quartz, Fe-oxides/hydroxides, rutile and Nb-rutile, xenotime, kassite, allanite, fluorapatite, epidote, ilmenite, monazite, sphene, and zircon, between 2 and 50 μm across. These occur in porous layers separating calcite laminae in the clayey coating on the layer below the surface of the speleothems, and are also incorporated within actual crystals. It is likely that they are derived from the weathered rocks of the Eocene flysch. Probably they were first transported into the caves by floodwaters forming cave sediments. Later, depending upon the climate conditions, they were moved by air currents or by water to the surface of active speleothems. They might also be redeposited from overlying soils enriched with wind-transported minerals from the flysch, or from higher passages filled with weathered flysch sediment, by drip water percolating through the fissured limestone. As some of the identified minerals are carriers of rare earth elements, Ti and Zr, their presence could affect any palaeoclimatic interpretations that are based upon the geochemical composition of the speleothems.

  17. Measurement Error in Atomic-Scale Scanning Transmission Electron Microscopy-Energy-Dispersive X-Ray Spectroscopy (STEM-EDS) Mapping of a Model Oxide Interface.

    Science.gov (United States)

    Spurgeon, Steven R; Du, Yingge; Chambers, Scott A

    2017-06-01

    With the development of affordable aberration correctors, analytical scanning transmission electron microscopy (STEM) studies of complex interfaces can now be conducted at high spatial resolution at laboratories worldwide. Energy-dispersive X-ray spectroscopy (EDS) in particular has grown in popularity, as it enables elemental mapping over a wide range of ionization energies. However, the interpretation of atomically resolved data is greatly complicated by beam-sample interactions that are often overlooked by novice users. Here we describe the practical factors-namely, sample thickness and the choice of ionization edge-that affect the quantification of a model perovskite oxide interface. Our measurements of the same sample, in regions of different thickness, indicate that interface profiles can vary by as much as 2-5 unit cells, depending on the spectral feature. This finding is supported by multislice simulations, which reveal that on-axis maps of even perfectly abrupt interfaces exhibit significant delocalization. Quantification of thicker samples is further complicated by channeling to heavier sites across the interface, as well as an increased signal background. We show that extreme care must be taken to prepare samples to minimize channeling effects and argue that it may not be possible to extract atomically resolved information from many chemical maps.

  18. Evaluation of LED therapy at 945nm on bone repair by micro x-ray fluorescence spectroscopy and scanning electron microscopy

    Science.gov (United States)

    Diamantino, Alexandre G.; Nicolau, Renata A.; de Oliveira, Marco A.; Santo, Ana Maria E.

    2011-07-01

    Phototherapy is able to modulate cellular metabolism of bone tissue and consequently accelerate the repair. The aim of this study was to evaluate the effect of this therapy in repair of bone monocortical defects in femurs of thirty male Wistar rats. The animals were divided into six groups (five animals for group), including three controls and three irradiated groups with different experimental times (14, 21, and 28 days after surgery). LED was used for the irradiation, emitting non-coherent light in the spectral range of 945+/-20 nm and output power of 48 mW, on one point of irradiation for four minutes. Seven treatment sessions were performed with 48 hours between sessions. For analysis on the bone repair, qualitative and quantitative assessments of Ca and P contents were done by micro x-ray fluorescence spectroscopy (μXRF) and the morphological structure was carried out using Scanning Electron Microscopy (SEM). The results showed the efficiency of infrared LED therapy, because the amount of mineral components analyzed by μXRF and the morphological features of cortical and trabecular bones, demonstrated by the SEM images, showed enhanced bone repair in the irradiated groups when compared to their corresponding control groups at all stages.

  19. Preformulation studies of Zidovudine derivatives: Acid dissociation constants, differential scanning calorimetry, thermogravimetry, x-ray powder diffractometry and aqueous stability studies.

    Science.gov (United States)

    Raviolo, Mónica A; Briñón, Margarita C

    2011-01-01

    As part as of the preformulation studies of new 5'-OH derivatives of zidovudine, compounds 2-6, their acid dissociation constants, Differential Scanning Calorimetry (DSC) and Thermogravimetry (TG) curves, X-Ray Powder diffractograms and aqueous stability are reported. A sensitive technique such as differential scanning potentiometry was used to determine the pKa constants of the above mentioned compounds. In addition, pKa values were calculated from theoretical methods, and no significant differences with those of experimental ones were observed. X-Ray Powder Diffractometry data demonstrated that compounds 2-4 were crystalline while 5 and 6 were amorphous. DSC analysis indicated that all of them presented an exothermic decomposition peak above 150 °C which is accompanied by a weight loss in the respective TG curves. The stability of these compounds in aqueous medium at different pH values was investigated, using a validated High Performance Liquid Chromatography (HPLC) method, which demonstrated to be rapid, selective, sensitive, accurate and stability-indicating. Good recovery, linearity and precision were also achieved. For all compounds the aqueous hydrolysis followed a pseudo-first-order kinetics, depending on pH and the union existing between AZT and the associate moiety. The hydrolysis was catalyzed by hydroxide ion in the 7.4-13.2 pH range, while all compounds exhibited pH-independent stability from acidic to neutral media (pHs 1.0-7.4).

  20. Detection and differentiation of bacterial spores in a mineral matrix by Fourier transform infrared spectroscopy (FTIR and chemometrical data treatment

    Directory of Open Access Journals (Sweden)

    Brandes Ammann Andrea

    2011-07-01

    Full Text Available Abstract Background Fourier transform infrared spectroscopy (FTIR has been used as analytical tool in chemistry for many years. In addition, FTIR can also be applied as a rapid and non-invasive method to detect and identify microorganisms. The specific and fingerprint-like spectra allow - under optimal conditions - discrimination down to the species level. The aim of this study was to develop a fast and reproducible non-molecular method to differentiate pure samples of Bacillus spores originating from different species as well as to identify spores in a simple matrix, such as the clay mineral, bentonite. Results We investigated spores from pure cultures of seven different Bacillus species by FTIR in reflection or transmission mode followed by chemometrical data treatment. All species investigated (B. atrophaeus, B. brevis, B. circulans, B. lentus, B. megaterium, B. subtilis, B. thuringiensis are typical aerobic soil-borne spore formers. Additionally, a solid matrix (bentonite and mixtures of benonite with spores of B. megaterium at various wt/wt ratios were included in the study. Both hierarchical cluster analysis and principal component analysis of the spectra along with multidimensional scaling allowed the discrimination of different species and spore-matrix-mixtures. Conclusions Our results show that FTIR spectroscopy is a fast method for species-level discrimination of Bacillus spores. Spores were still detectable in the presence of the clay mineral bentonite. Even a tenfold excess of bentonite (corresponding to 2.1 × 1010 colony forming units per gram of mineral matrix still resulted in an unambiguous identification of B. megaterium spores.

  1. Differential scanning calorimetry of whole Escherichia coli treated with the antimicrobial peptide MSI-78 indicate a multi-hit mechanism with ribosomes as a novel target

    Directory of Open Access Journals (Sweden)

    Alexander M. Brannan

    2015-12-01

    Full Text Available Differential Scanning Calorimetry (DSC of intact Escherichia coli (E. coli was used to identify non-lipidic targets of the antimicrobial peptide (AMP MSI-78. The DSC thermograms revealed that, in addition to its known lytic properties, MSI-78 also has a striking effect on ribosomes. MSI-78’s effect on DSC scans of bacteria was similar to that of kanamycin, an antibiotic drug known to target the 30S small ribosomal subunit. An in vitro transcription/translation assay helped confirm MSI-78’s targeting of ribosomes. The scrambled version of MSI-78 also affected the ribosome peak of the DSC scans, but required greater amounts of peptide to cause a similar effect to the unscrambled peptide. Furthermore, the effect of the scrambled peptide was not specific to the ribosomes; other regions of the DSC thermogram were also affected. These results suggest that MSI-78’s effects on E. coli are at least somewhat dependent on its particular structural features, rather than a sole function of its overall charge and hydrophobicity. When considered along with earlier work detailing MSI-78’s membrane lytic properties, it appears that MSI-78 operates via a multi-hit mechanism with multiple targets.

  2. [Particle Size and Number Density Online Analysis for Particle Suspension with Polarization-Differentiation Elastic Light Scattering Spectroscopy].

    Science.gov (United States)

    Chen, Wei-kang; Fang, Hui

    2016-03-01

    The basic principle of polarization-differentiation elastic light scattering spectroscopy based techniques is that under the linear polarized light incidence, the singlely scattered light from the superficial biological tissue and diffusively scattered light from the deep tissue can be separated according to the difference of polarization characteristics. The novel point of the paper is to apply this method to the detection of particle suspension and, to realize the simultaneous measurement of its particle size and number density in its natural status. We design and build a coaxial cage optical system, and measure the backscatter signal at a specified angle from a polystyrene microsphere suspension. By controlling the polarization direction of incident light with a linear polarizer and adjusting the polarization direction of collected light with another linear polarizer, we obtain the parallel polarized elastic light scattering spectrum and cross polarized elastic light scattering spectrum. The difference between the two is the differential polarized elastic light scattering spectrum which include only the single scattering information of the particles. We thus compare this spectrum to the Mie scattering calculation and extract the particle size. We then also analyze the cross polarized elastic light scattering spectrum by applying the particle size already extracted. The analysis is based on the approximate expressions taking account of light diffusing, from which we are able to obtain the number density of the particle suspension. We compare our experimental outcomes with the manufacturer-provided values and further analyze the influence of the particle diameter standard deviation on the number density extraction, by which we finally verify the experimental method. The potential applications of the method include the on-line particle quality monitoring for particle manufacture as well as the fat and protein density detection of milk products.

  3. Fourier-transform-infrared-spectroscopy based spectral-biomarker selection towards optimum diagnostic differentiation of oral leukoplakia and cancer.

    Science.gov (United States)

    Banerjee, Satarupa; Pal, Mousumi; Chakrabarty, Jitamanyu; Petibois, Cyril; Paul, Ranjan Rashmi; Giri, Amita; Chatterjee, Jyotirmoy

    2015-10-01

    In search of specific label-free biomarkers for differentiation of two oral lesions, namely oral leukoplakia (OLK) and oral squamous-cell carcinoma (OSCC), Fourier-transform infrared (FTIR) spectroscopy was performed on paraffin-embedded tissue sections from 47 human subjects (eight normal (NOM), 16 OLK, and 23 OSCC). Difference between mean spectra (DBMS), Mann-Whitney's U test, and forward feature selection (FFS) techniques were used for optimising spectral-marker selection. Classification of diseases was performed with linear and quadratic support vector machine (SVM) at 10-fold cross-validation, using different combinations of spectral features. It was observed that six features obtained through FFS enabled differentiation of NOM and OSCC tissue (1782, 1713, 1665, 1545, 1409, and 1161 cm(-1)) and were most significant, able to classify OLK and OSCC with 81.3 % sensitivity, 95.7 % specificity, and 89.7 % overall accuracy. The 43 spectral markers extracted through Mann-Whitney's U Test were the least significant when quadratic SVM was used. Considering the high sensitivity and specificity of the FFS technique, extracting only six spectral biomarkers was thus most useful for diagnosis of OLK and OSCC, and to overcome inter and intra-observer variability experienced in diagnostic best-practice histopathological procedure. By considering the biochemical assignment of these six spectral signatures, this work also revealed altered glycogen and keratin content in histological sections which could able to discriminate OLK and OSCC. The method was validated through spectral selection by the DBMS technique. Thus this method has potential for diagnostic cost minimisation for oral lesions by label-free biomarker identification.

  4. Differentiation between sarcoidosis and Hodgkin’s lymphoma based on mediastinal lymph node involvement pattern: Evaluation using spiral CT scan

    International Nuclear Information System (INIS)

    Mehrian, Payam; Ebrahimzadeh, Seyed Amir

    2013-01-01

    The purpose of this study was to determine the specific and detailed anatomic sites and morphologic characteristics of mediastinal lymph nodes on spiral computed tomography for the purpose of differentiation between sarcoidosis and Hodgkin’s lymphoma. Anatomical distribution of mediastinal lymph nodes on spiral CT was reviewed in 39 patients with sarcoidosis and 37 patients with Hodgkin’s lymphoma using the International Association for the Study of Lung Cancer (IASLC) lymph node map. Other morphologic features such as lymph node calcification or coalescence of adjacent lymph nodes were also compared. Zone 10 was involved more often in sarcoidosis than in Hodgkin’s lymphoma. On the other hand, there was a higher tendency for presence of zone 1 and 3 as well as retrocrural and internal mammary lymphadenopathy in Hodgkin’s lymphoma than in sarcoidosis. Sarcoidosis presented with intranodal calcifications more often than Hodgkin’s lymphoma. Coalescence, pressure effect on adjacent structures and central cavitations were significantly more common in Hodgkin’s lymphoma. Findings of the present study indicate that specific anatomical distribution and morphological patterns of mediastinal lymph nodes, as demonstrated on spiral CT, can be useful in differentiating sarcoidosis from Hodgkin’s lymphoma

  5. On the geometry dependence of differential pathlength factor for near-infrared spectroscopy. I. Steady-state with homogeneous medium

    Science.gov (United States)

    Piao, Daqing; Barbour, Randall L.; Graber, Harry L.; Lee, Daniel C.

    2015-01-01

    Abstract. This work analytically examines some dependences of the differential pathlength factor (DPF) for steady-state photon diffusion in a homogeneous medium on the shape, dimension, and absorption and reduced scattering coefficients of the medium. The medium geometries considered include a semi-infinite geometry, an infinite-length cylinder evaluated along the azimuthal direction, and a sphere. Steady-state photon fluence rate in the cylinder and sphere geometries is represented by a form involving the physical source, its image with respect to the associated extrapolated half-plane, and a radius-dependent term, leading to simplified formula for estimating the DPFs. With the source-detector distance and medium optical properties held fixed across all three geometries, and equal radii for the cylinder and sphere, the DPF is the greatest in the semi-infinite and the smallest in the sphere geometry. When compared to the results from finite-element method, the DPFs analytically estimated for 10 to 25 mm source–detector separations on a sphere of 50 mm radius with μa=0.01  mm−1 and μs′=1.0  mm−1 are on average less than 5% different. The approximation for sphere, generally valid for a diameter ≥20 times of the effective attenuation pathlength, may be useful for rapid estimation of DPFs in near-infrared spectroscopy of an infant head and for short source–detector separation. PMID:26465613

  6. Satellite monitoring of different vegetation types by differential optical absorption spectroscopy (DOAS in the red spectral range

    Directory of Open Access Journals (Sweden)

    T. Wagner

    2007-01-01

    Full Text Available A new method for the satellite remote sensing of different types of vegetation and ocean colour is presented. In contrast to existing algorithms relying on the strong change of the reflectivity in the red and near infrared spectral region, our method analyses weak narrow-band (few nm reflectance structures (i.e. "fingerprint" structures of vegetation in the red spectral range. It is based on differential optical absorption spectroscopy (DOAS, which is usually applied for the analysis of atmospheric trace gas absorptions. Since the spectra of atmospheric absorption and vegetation reflectance are simultaneously included in the analysis, the effects of atmospheric absorptions are automatically corrected (in contrast to other algorithms. The inclusion of the vegetation spectra also significantly improves the results of the trace gas retrieval. The global maps of the results illustrate the seasonal cycles of different vegetation types. In addition to the vegetation distribution on land, they also show patterns of biological activity in the oceans. Our results indicate that improved sets of vegetation spectra might lead to more accurate and more specific identification of vegetation type in the future.

  7. Application of magnetic resonance spectroscopy in the differentiation of high-grade brain neoplasm and inflammatory brain lesions

    Energy Technology Data Exchange (ETDEWEB)

    Ferraz-Filho, Jose Roberto Lopes; Santana-Netto, Pedro Vieira; Sgnolf, Aline [FAMERP Medical School, Sao Jose do Rio Preto SP (Brazil). Image Dept.], e-mail: jrl.ferraz@terra.com.br; Rocha-Filho, Jose Alves; Mauad, Fernando [FAMERP Medical School, Sao Jose do Rio Preto SP (Brazil). Radiology Dept.; Sanches, Rafael Angelo [FAMERP Medical School, Sao Jose do Rio Preto SP (Brazil). Imaging Dept.

    2009-06-15

    This study aims at evaluating the application of magnetic resonance spectroscopy (MRS) in the differential diagnosis of brain tumors and inflammatory brain lesions. The examinations of 81 individuals, who performed brain MRS and were retrospectively analyzed. The patients with ages between 10 and 80 years old, were divided into two groups. Group A consisted of 42 individuals with diagnoses of cerebral toxoplasmosis and Group B was formed of 39 individuals with diagnosis of glial neoplasms. On analyzing the ROC curve, the discriminatory boundary for the Cho/Cr ratio between inflammatory lesions and tumors was 1.97 and for the NAA/Cr ratio it was 1.12. RMS is an important method useful in the distinction of inflammatory brain lesions and high-degree tumors when the Cho/Cr ratio is greater than 1.97 and the NAA/Cr ratio is less than 1.12. And so this method is important in the planning of treatment and monitoring of the therapeutic efficiency. (author)

  8. Application of magnetic resonance spectroscopy in the differentiation of high-grade brain neoplasm and inflammatory brain lesions

    International Nuclear Information System (INIS)

    Ferraz-Filho, Jose Roberto Lopes; Santana-Netto, Pedro Vieira; Sgnolf, Aline; Rocha-Filho, Jose Alves; Mauad, Fernando; Sanches, Rafael Angelo

    2009-01-01

    This study aims at evaluating the application of magnetic resonance spectroscopy (MRS) in the differential diagnosis of brain tumors and inflammatory brain lesions. The examinations of 81 individuals, who performed brain MRS and were retrospectively analyzed. The patients with ages between 10 and 80 years old, were divided into two groups. Group A consisted of 42 individuals with diagnoses of cerebral toxoplasmosis and Group B was formed of 39 individuals with diagnosis of glial neoplasms. On analyzing the ROC curve, the discriminatory boundary for the Cho/Cr ratio between inflammatory lesions and tumors was 1.97 and for the NAA/Cr ratio it was 1.12. RMS is an important method useful in the distinction of inflammatory brain lesions and high-degree tumors when the Cho/Cr ratio is greater than 1.97 and the NAA/Cr ratio is less than 1.12. And so this method is important in the planning of treatment and monitoring of the therapeutic efficiency. (author)

  9. Radio-isotope scanning using labelled bleomycin in positive and differential diagnosis of primary and secondary malignant pulmonary lesions

    International Nuclear Information System (INIS)

    Robert, J.; Bertrand, A.; Nouel, J.P.; Witz, H.

    1975-01-01

    A lung scan using bleomycin labelled with cobalt 57 was carried out in 308 patients representing 191 primary malignant tumours, 48 pulmonary metastases and 69 benign lesions. The primary and secondary malignant lesions always gave rise to a hyperactive focus except in 8 cases of primary lung tumour. The negative examination may be explained, either by the small size of the lesion or by radiotherapy in progress. Among the benign lesions, only advanced tuberculosis and very inflammatory lung diseases frequently took up labelled bleomycin (15 hyperactive foci out of 69 benign lesions). Quantitative measurements, i.e. ratio of the lesional activity/activity of healthy lung tissue, were carried out in all patients. The malignant lesions were usually more active than the benign lesions. There was no definite correlation between the uptake of labelled bleomycin and the histological nature of the lesion. However, undifferentiated and anaplastic carcinomas were often more active. One should emphasize that these results show that a hyperactive focus has a 94% chance of being a carcinoma. The absence of bleomycin uptake means that there is a 92% chance of a benign lesion [fr

  10. Multilayered cuprate superconductor Ba2Ca5Cu6O12(O1-x,Fx) 2 studied by temperature-dependent scanning tunneling microscopy and spectroscopy

    Science.gov (United States)

    Sugimoto, Akira; Ekino, Toshikazu; Gabovich, Alexander M.; Sekine, Ryotaro; Tanabe, Kenji; Tokiwa, Kazuyasu

    2017-05-01

    Scanning tunneling microscopy/spectroscopy (STM/STS) measurements were carried out on a multilayered cuprate superconductor Ba2Ca5Cu6O12 (O1 -x,Fx )2. STM topography revealed random spot structures with the characteristic length ≤0.5 nm. The conductance spectra d I /d V (V ) show the coexistence of smaller gaps ΔS and large gaps (pseudogaps) ΔL. The pseudogap-related features in the superconducting state were traced with the spatial resolution of ˜0.07 nm. Here, I and V are the tunnel current and bias voltage, respectively. The temperature, T , dependence of ΔS follows the reduced Bardeen-Cooper-Schrieffer (BCS) dependence. The hallmark ratio 2 ΔS(T =0 ) /kBTc equals to 4.9, which is smaller than those of other cuprate superconductors. Here, Tc is the superconducting critical temperature and kB is the Boltzmann constant. The larger gap ΔL survives in the normal state and even increases with T above Tc. The T dependencies of the spatial distributions for both relevant gaps (Δ map), as well as for each gap separately (ΔS and ΔL), were obtained. From the histogram of Δ map, the averaged gap values were found to be Δ¯S=˜24 meV and Δ¯L=˜79 meV. The smaller gap ΔS shows a spatially homogeneous distribution while the larger gap ΔL is quite inhomogeneous, indicating that rather homogeneous superconductivity coexists with the patchy distributed pseudogap. The spatial variation length ξΔ L of ΔL correlates with the scale of the topography spot structures, being approximately 0.4 nm. This value is considerably smaller than the coherence length of this class of superconductors, suggesting that ΔL is strongly affected by the disorder of the apical O/F.

  11. Investigation of the cutaneous penetration behavior of dexamethasone loaded to nano-sized lipid particles by EPR spectroscopy, and confocal Raman and laser scanning microscopy.

    Science.gov (United States)

    Lohan, Silke B; Saeidpour, Siavash; Solik, Agnieszka; Schanzer, Sabine; Richter, Heike; Dong, Pin; Darvin, Maxim E; Bodmeier, Roland; Patzelt, Alexa; Zoubari, Gaith; Unbehauen, Michael; Haag, Rainer; Lademann, Jürgen; Teutloff, Christian; Bittl, Robert; Meinke, Martina C

    2017-07-01

    An improvement of the penetration efficiency combined with the controlled release of actives in the skin can facilitate the medical treatment of skin diseases immensely. Dexamethasone (Dx), a synthetic glucocorticoid, is frequently used for the treatment of inflammatory skin diseases. To investigate the penetration of nano-sized lipid particles (NLP) loaded with Dx in comparison to a commercially available base cream, different techniques were applied. Electron paramagnetic resonance (EPR) spectroscopy was used to monitor the penetration of Dx, which was covalently labeled with the spin probe 3-(Carboxy)-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (PCA). The penetration into hair follicles was studied using confocal laser scanning microscopy (CLSM) with curcumin-loaded NLP. The penetration of the vehicle was followed by confocal Raman microscopy (CRM). Penetration studies using excised porcine skin revealed a more than twofold higher penetration efficiency for DxPCA into the stratum corneum (SC) after 24h incubation compared to 4h incubation when loaded to the NLP, whereas when applied in the base cream, almost no further penetration was observed beyond 4h. The distribution of DxPCA within the SC was investigated by consecutive tape stripping. The release of DxPCA from the base cream after 24h in deeper SC layers and the viable epidermis was shown by EPR. For NLP, no release from the carrier was observed, although DxPCA was detectable in the skin after the complete SC was removed. This phenomenon can be explained by the penetration of the NLP into the hair follicles. However, penetration profiles measured by CRM indicate that NLP did not penetrate as deeply into the SC as the base cream formulation. In conclusion, NLP can improve the accumulation of Dx in the skin and provide a reservoir within the SC and in the follicular infundibula. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Weathering properties of treated southern yellow pine wood examined by X-ray photoelectron spectroscopy, scanning electron microscopy and physical characterization

    International Nuclear Information System (INIS)

    Salaita, Ghaleb N.; Ma, Frank M.S.; Parker, Trudy C.; Hoflund, Gar B.

    2008-01-01

    In this study the weathering behavior of southern yellow pine (SYP) wood samples pretreated in different solutions has been examined using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and various types of physical characterization regarding material loss and discoloration. The treatment solutions include water as a control, a commercially available water repellent (WR) wood treating additive and polyethylene glycol (PEG) products including PEG PLUS TM , PEG 8000 solutions and Compound 20M in varying concentrations. All contained the wood preservative chromated copper arsenate (CCA). One sample was treated with a CCA solution only. The treatments were carried out at 20 deg. C and 150 psig for 1/2 h after exposure to vacuum (28 mmHg) for 15 min. Simulated weathering was achieved in an Atlas 65-W Weather-Ometer for 2000 h with both light and dark periods and rain. The temperature ranged from 23 deg. C during the dark cycle to 35 deg. C during the light cycle. With weathering the XPS O/C ratios increase due to oxidation of the surface. Exposure to UV light results in bond breakage and reaction with oxygen in the presence of air to form organic functional groups such as , , C=O and/or O-C-O. These oxidized products can protect the underlying wood from deterioration if they are insoluble in water and remain on the surface as a protective coating. If soluble, rain washes the compounds away and assists in the degradation. Correlated changes are observed in the XPS O/C ratios, the high-resolution XPS C 1s spectra, the SEM micrographs and physical measurements including thickness alteration, weight loss, and discoloration by yellowing or whitening of the weathered wood. The PEG treatments are effective in protecting wood with the 2% PEG PLUS treatment providing the best weathering behavior similar to that of the CCA treatment. The WR and water treatments yield the poorest weathering properties

  13. Shape Memory Alloys for Monitoring Minor Over-Heating/Cooling Based on the Temperature Memory Effect via Differential Scanning Calorimetry: A Review of Recent Progress

    Science.gov (United States)

    Wang, T. X.; Huang, W. M.

    2017-12-01

    The recent development in the temperature memory effect (TME) via differential scanning calorimetry in shape memory alloys is briefly discussed. This phenomenon was also called the thermal arrest memory effect in the literature. However, these names do not explicitly reveal the potential application of this phenomenon in temperature monitoring. On the other hand, the standard testing process of the TME has great limitation. Hence, it cannot be directly applied for temperature monitoring in most of the real engineering applications in which temperature fluctuation occurs mostly in a random manner within a certain range. However, as shown here, after proper modification, we are able to monitor the maximum or minimum temperature in either over-heating or over-cooling with reasonable accuracy.

  14. Evaluation of shrinkage temperature of bovine pericardium tissue for bioprosthetic heart valve application by differential scanning calorimetry and freeze-drying microscopy

    Directory of Open Access Journals (Sweden)

    Virgilio Tattini Jr

    2007-03-01

    Full Text Available Bovine pericardium bioprosthesis has become a commonly accepted device for heart valve replacement. Present practice relies on the measurement of shrinkage temperature, observed as a dramatic shortening of tissue length. Several reports in the last decade have utilized differential scanning calorimetry (DSC as an alternative method to determine the shrinkage temperature, which is accompanied by the absorption of heat, giving rise to an endothermic peak over the shrinkage temperature range of biological tissues. Usually, freeze-drying microscope is used to determine collapse temperature during the lyophilization of solutions. On this experiment we used this technique to study the shrinkage event. The aim of this work was to compare the results of shrinkage temperature obtained by DSC with the results obtained by freeze-drying microscopy. The results showed that both techniques provided excellent sensitivity and reproducibility, and gave information on the thermal shrinkage transition via the thermodynamical parameters inherent of each method.

  15. One-step simultaneous differential scanning calorimetry-FTIR microspectroscopy to quickly detect continuous pathways in the solid-state glucose/asparagine Maillard reaction.

    Science.gov (United States)

    Hwang, Deng-Fwu; Hsieh, Tzu-Feng; Lin, Shan-Yang

    2013-01-01

    The stepwise reaction pathway of the solid-state Maillard reaction between glucose (Glc) and asparagine (Asn) was investigated using simultaneous differential scanning calorimetry (DSC)-FTIR microspectroscopy. The color change and FTIR spectra of Glc-Asn physical mixtures (molar ratio = 1:1) preheated to different temperatures followed by cooling were also examined. The successive reaction products such as Schiff base intermediate, Amadori product, and decarboxylated Amadori product in the solid-state Glc-Asn Maillard reaction were first simultaneously evidenced by this unique DSC-FTIR microspectroscopy. The color changed from white to yellow-brown to dark brown, and appearance of new IR peaks confirmed the formation of Maillard reaction products. The present study clearly indicates that this unique DSC-FTIR technique not only accelerates but also detects precursors and products of the Maillard reaction in real time.

  16. F-18 FDG-PET/CT evaluation of patients with differentiated thyroid cancer with negative I-131 total body scan and high thyroglobulin level.

    Science.gov (United States)

    Bertagna, Francesco; Bosio, Giovanni; Biasiotto, Giorgio; Rodella, Carlo; Puta, Erinda; Gabanelli, Sara; Lucchini, Silvia; Merli, Giuseppe; Savelli, Giordano; Giubbini, Raffaele; Rosenbaum, Joshua; Alavi, Abass

    2009-11-01

    The aim was to evaluate the incremental diagnostic rate of F-18 fluoro-fluorodeoxygulose positron emission tomography/computed tomography (F-18 FDG-PET/CT) in patients with negative I-131 whole body scans and high Tg levels. The secondary end points were correlations between F-18 FDG-PET/CT positive results and Tg levels and comparison between F-18 FDG-PET/CT accuracy in patients "on-therapy" with suppressed thyroid stimulating hormone (TSH) and those with high TSH levels. We studied 52 patients who had undergone total thyroidectomy and remnant ablation; they had high Tg levels (average = 156 ng/mL; SD +/- 274) after 3 weeks of levothyroxine withdrawal and negative I-131 total body scans after therapeutic doses. We noted a statistically significant positive correlation between F-18 FDG-PET/CT positive results and Tg levels, irrespective of levothyroxine therapy regimen. Tg levels between F-18 FDG-PET/CT positive/negative groups were significantly different and we did not note any statistically significant correlation between F-18 FDG-PET/CT results and TSH levels, tumor size, and combination of Tg/TSH levels. Our results indicate that F-18 FDG-PET/CT is a useful diagnostic tool in patients with differentiated thyroid carcinoma and with negative I-131 total body scans and high Tg levels. The levothyroxine therapy regimen does not influence F-18 FDG-PET/CT results and the rate of F-18 FDG-PET/CT positive results appears to correlate with the Tg levels. The highest accuracy is reached when the study is performed for patients with Tg levels higher than 21 ng/mL.

  17. Timing of post 131I ablation diagnostic whole body scan in differentiated thyroid cancer patients. Less than four months post ablation may be too early.

    Science.gov (United States)

    Winter, M; Winter, J; Heinzel, A; Behrendt, F F; Krohn, T; Mottaghy, F M; Verburg, F A

    2015-01-01

    to determine whether the first three months after 131I ablation is too early to perform radioiodine diagnostic whole body scintigraphy (dxWBS) in differentiated thyroid carcinoma patients. The files of 462 patients who were treated for DTC in our hospital were reviewed. All patients underwent surgical thyroidectomy. 146 patients had data available on a. a dxWBS which was performed less than four months (max 120 days) after 131I ablation with concurrent stimulated TSH stimulated thyroglobulin (Tg) measurement without further therapeutic measures between ablation and dxWBS and b. a second dxWBS or 131I therapy (rxWBS) within 1.5 years after ablation. A discordance between the initial and follow-up scan was found in 25/129 (19%) patients: of 54 patients with a positive initial dxWBS, scan results of a second dxWBS or rxWBS obtained with a suitable distance to the initial scan contradicted the initial one in 15 patients (27%). New lesions were discovered in 10/74 negative first dxWBS cases (14%). A discordance between the initial and follow-up stimulated Tg was found in 5/129 (4%) patients: 2/90 (2%) of patients with a negative stimulated Tg at initial dxWBS subsequently showed a positive results whereas 3/29 (10%) patients with an initially positive Tg showed a negative Tg level at the second procedure. Less than four months after 131I ablation is too early to perform radioiodine diagnostic whole body scintigraphy with concurrent TSH stimulated Tg measurement. The identification of the right, later, timepoint however requires further research.

  18. Altered nitrogen metabolism associated with de-differentiated suspension cultures derived from root cultures of Datura stramonium studied by heteronuclear multiple bond coherence (HMBC) NMR spectroscopy.

    Science.gov (United States)

    Fliniaux, Ophélie; Mesnard, François; Raynaud-Le Grandic, Sophie; Baltora-Rosset, Sylvie; Bienaimé, Christophe; Robins, Richard J; Fliniaux, Marc-André

    2004-05-01

    De-differentiation of transformed root cultures of Datura stramonium has previously been shown to cause a loss of tropane alkaloid synthetic capacity. This indicates a marked shift in physiological status, notably in the flux of primary metabolites into tropane alkaloids. Nitrogen metabolism in transformed root cultures of D. stramonium (an alkaloid-producing system) and de-differentiated suspension cultures derived therefrom (a non-producing system) has been compared using Nuclear Magnetic Resonance (NMR) spectroscopy. (15)N-Labelled precursors [((15)NH(4))(2)SO(4) and K(15)NO(3)] were fed and their incorporation into nitrogenous metabolites studied using Heteronuclear Multiple Bond Coherence (HMBC) NMR spectroscopy. In both cultures, the same amino acids were resolved in the HMBC spectra. However, marked differences were found in the intensity of labelling of a range of nitrogenous compounds. In differentiated root cultures, cross-peaks corresponding to secondary metabolites, such as tropine, were observed, whereas these were absent in the de-differentiated cultures. By contrast, N- acetylputrescine and gamma-aminobutyric acid (GABA) accumulated in the de-differentiated cultures to a much larger extent than in the root cultures. It can therefore be suggested that the loss of alkaloid biosynthesis was compensated by the diversion of putrescine metabolism away from the tropane pathway and toward the synthesis of GABA via N-acetylputrescine.

  19. An instrument for measurements of BrO with LED-based Cavity-Enhanced Differential Optical Absorption Spectroscopy

    Science.gov (United States)

    Hoch, D. J.; Buxmann, J.; Sihler, H.; Pöhler, D.; Zetzsch, C.; Platt, U.

    2014-01-01

    The chemistry of the troposphere and specifically the global tropospheric ozone budget is affected by reactive halogen species such as bromine monoxide (BrO) or chlorine monoxide (ClO). Especially BrO plays an important role in the processes of ozone destruction, disturbance of NOx and HOx chemistry, oxidation of dimethyl sulfide (DMS), and the deposition of elementary mercury. In the troposphere BrO has been detected in polar regions, at salt lakes, in volcanic plumes, and in the marine boundary layer. For a better understanding of these processes, field measurements as well as reaction chamber studies are performed. In both cases instruments with high spatial resolution and high sensitivity are necessary. A Cavity-Enhanced Differential Optical Absorption Spectroscopy (CE-DOAS) instrument with an open path measurement cell was designed and applied. For the first time, a CE-DOAS instrument is presented using an UV LED in the 325-365 nm wavelength range. In laboratory studies, BrO as well as HONO, HCHO, O3, and O4 could be reliably determined at detection limits of 20 ppt for BrO, 9.1 ppb for HCHO, 970 ppt for HONO, and 91 ppb for O3, for five minutes integration time. The best detection limits were achieved for BrO (11 ppt), HCHO (5.1 ppb), HONO (490 ppt), and O3 (59 ppb) for integration times of 81 minutes or less. Comparison with established White system (WS) DOAS and O3 monitor measurements demonstrate the reliability of the instrument.

  20. Remote measurement of high preeruptive water vapor emissions at Sabancaya volcano by passive differential optical absorption spectroscopy

    Science.gov (United States)

    Kern, Christoph; Masias, Pablo; Apaza, Fredy; Reath, Kevin; Platt, Ulrich

    2017-01-01

    Water (H2O) is by far the most abundant volcanic volatile species and plays a predominant role in driving volcanic eruptions. However, numerous difficulties associated with making accurate measurements of water vapor in volcanic plumes have limited their use as a diagnostic tool. Here we present the first detection of water vapor in a volcanic plume using passive visible-light differential optical absorption spectroscopy (DOAS). Ultraviolet and visible-light DOAS measurements were made on 21 May 2016 at Sabancaya Volcano, Peru. We find that Sabancaya's plume contained an exceptionally high relative water vapor abundance 6 months prior to its November 2016 eruption. Our measurements yielded average sulfur dioxide (SO2) emission rates of 800–900 t/d, H2O emission rates of around 250,000 t/d, and an H2O/SO2 molecular ratio of 1000 which is about an order of magnitude larger than typically found in high-temperature volcanic gases. We attribute the high water vapor emissions to a boiling-off of Sabancaya's hydrothermal system caused by intrusion of magma to shallow depths. This hypothesis is supported by a significant increase in the thermal output of the volcanic edifice detected in infrared satellite imagery leading up to and after our measurements. Though the measurement conditions encountered at Sabancaya were very favorable for our experiment, we show that visible-light DOAS systems could be used to measure water vapor emissions at numerous other high-elevation volcanoes. Such measurements would provide observatories with additional information particularly useful for forecasting eruptions at volcanoes harboring significant hydrothermal systems.

  1. Measurement of atmospheric ammonia at a dairy using differential optical absorption spectroscopy in the mid-ultraviolet

    Science.gov (United States)

    Mount, George H.; Rumburg, Brian; Havig, Jeff; Lamb, Brian; Westberg, Hal; Yonge, David; Johnson, Kristen; Kincaid, Ronald

    Ammonia is the most abundant basic gas in the atmosphere, and after N 2 and N 2O is the most abundant nitrogen-containing specie (Seinfeld and Pandis, 1998. Atmospheric Chemistry and Physics: from air pollution to climate changes. Wiley, New York). Typical concentrations of ammonia in the boundary layer range from environmental concern. In the US, ≈85% of ammonia emissions come from livestock operations (EPA Trends, 1998. www.epa.gov/ttn/chief/trends98/chapter2.pdf). Dairy farms constitute a large fraction of the livestock inventory. Current estimates of ammonia emissions to the atmosphere are characterized by a high degree of uncertainty, and so it is very important to obtain better estimates of ammonia emissions. We are working at the Washington State University research dairy to quantify ammonia emissions and investigate the effects of various mitigation strategies on those emissions. We describe here a new instrument utilizing the differential optical absorption spectroscopy (DOAS) technique to measure ammonia in the mid-ultraviolet with a detectability limit of about 1 ppb. DOAS avoids many of the problems that have thwarted past ammonia concentration measurements. Initial results show concentrations in the barn/concrete yard areas in the tens of parts per million range, over the slurry lagoons of hundreds of parts per billion to low parts per million, and low parts per million levels after initial slurry applications onto pastureland. Future papers will report on emission fluxes from the various parts of the dairy and the results of mitigation strategies; we show here initial data results. For a recent review of ammonia volatilization from dairy farms, see Bussink and Oenema (Nutrient Cycling in Agroecosystems 51(1998) 19).

  2. Remote measurement of high preeruptive water vapor emissions at Sabancaya volcano by passive differential optical absorption spectroscopy

    Science.gov (United States)

    Kern, Christoph; Masias, Pablo; Apaza, Fredy; Reath, Kevin A.; Platt, Ulrich

    2017-05-01

    Water (H2O) is by far the most abundant volcanic volatile species and plays a predominant role in driving volcanic eruptions. However, numerous difficulties associated with making accurate measurements of water vapor in volcanic plumes have limited their use as a diagnostic tool. Here we present the first detection of water vapor in a volcanic plume using passive visible-light differential optical absorption spectroscopy (DOAS). Ultraviolet and visible-light DOAS measurements were made on 21 May 2016 at Sabancaya Volcano, Peru. We find that Sabancaya's plume contained an exceptionally high relative water vapor abundance 6 months prior to its November 2016 eruption. Our measurements yielded average sulfur dioxide (SO2) emission rates of 800-900 t/d, H2O emission rates of around 250,000 t/d, and an H2O/SO2 molecular ratio of 1000 which is about an order of magnitude larger than typically found in high-temperature volcanic gases. We attribute the high water vapor emissions to a boiling-off of Sabancaya's hydrothermal system caused by intrusion of magma to shallow depths. This hypothesis is supported by a significant increase in the thermal output of the volcanic edifice detected in infrared satellite imagery leading up to and after our measurements. Though the measurement conditions encountered at Sabancaya were very favorable for our experiment, we show that visible-light DOAS systems could be used to measure water vapor emissions at numerous other high-elevation volcanoes. Such measurements would provide observatories with additional information particularly useful for forecasting eruptions at volcanoes harboring significant hydrothermal systems.

  3. Development of a portable active long-path differential optical absorption spectroscopy system for volcanic gas measurements

    Science.gov (United States)

    Vita, Fabio; Kern, Christoph; Inguaggiato, Salvatore

    2014-01-01

    Active long-path differential optical absorption spectroscopy (LP-DOAS) has been an effective tool for measuring atmospheric trace gases for several decades. However, instruments were large, heavy and power-inefficient, making their application to remote environments extremely challenging. Recent developments in fibre-coupling telescope technology and the availability of ultraviolet light emitting diodes (UV-LEDS) have now allowed us to design and construct a lightweight, portable, low-power LP-DOAS instrument for use at remote locations and specifically for measuring degassing from active volcanic systems. The LP-DOAS was used to measure sulfur dioxide (SO2) emissions from La Fossa crater, Vulcano, Italy, where column densities of up to 1.2 × 1018 molec cm−2 (~ 500 ppmm) were detected along open paths of up to 400 m in total length. The instrument's SO2 detection limit was determined to be 2 × 1016 molec cm−2 (~ 8 ppmm), thereby making quantitative detection of even trace amounts of SO2 possible. The instrument is capable of measuring other volcanic volatile species as well. Though the spectral evaluation of the recorded data showed that chlorine monoxide (ClO) and carbon disulfide (CS2) were both below the instrument's detection limits during the experiment, the upper limits for the X / SO2 ratio (X = ClO, CS2) could be derived, and yielded 2 × 10−3 and 0.1, respectively. The robust design and versatility of the instrument make it a promising tool for monitoring of volcanic degassing and understanding processes in a range of volcanic systems.

  4. High Pressure Scanning Tunneling Microscopy and High PressureX-ray Photoemission Spectroscopy Studies of Adsorbate Structure,Composition and Mobility during Catalytic Reactions on A Model SingleCrystal

    Energy Technology Data Exchange (ETDEWEB)

    Montano, Max O. [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    Our research focuses on taking advantage of the ability of scanning tunneling microscopy (STM) to operate at high-temperatures and high-pressures while still providing real-time atomic resolution images. We also utilize high-pressure x-ray photoelectron spectroscopy (HPXPS) to monitor systems under identical conditions thus giving us chemical information to compare and contrast with the structural and dynamic data provided by STM.

  5. Structural and functional differentiation of the embryonic chick pineal organ in vivo and in vitro. A scanning electron-microscopic and radioimmunoassay study.

    Science.gov (United States)

    Möller, W; Möller, G

    1990-05-01

    The development of sensory structures in the pineal organ of the chick was examined by means of scanning electron microscopy from embryonic day 10 through day 12 post-hatching. At embryonic day 10, the wall of the tubules within the pineal primordium is composed of cells with unspecialized luminal surface. Differentiation of sensory structures starts at embryonic day 12 when pinealocytes and supporting cells can be distinguished. Pinealocytes are recognized by virtue of an inner segment only rarely endowed with a cilium, whereas supporting cells exhibit numerous short microvilli. Further differentiation of the sensory apparatus is achieved by development of an oval-shaped, biconcave swelling at the tip of the cilium, 1 x 2 microns in size, and a collar of long microvilli at the base of the inner segment. Membrane specializations of sensory cilia, however, were not detected. Since during embryonic life new tubules and follicles are continuously formed, all stages of differentiation of sensory structures are found in the chick pineal organ during the second half of the incubation period and the first two weeks after hatching. In 200-microns-thick Vibratome sections of chick-embryo pineal organs cultured in medium BM 86 Wissler for periods up to 13 days the cytodifferentiation parallels the development in vivo. Using an organ-culture system the 24-h release of melatonin into the culture medium was measured by means of radioimmunoassay after solid-phase extraction. At embryonic day 10, the 24-h secretion of melatonin was at the lower range of detection of the RIA (5 pg). The rapid increase in 24-h secretion in melatonin until hatching (approximately 50 micrograms) is approximated by an exponential curve.

  6. Probing the structure and nano-scale mechanical properties of polymer surfaces with scanning force microscopy and sum frequency vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gracias, David Hugo [Univ. of California, Berkeley, CA (United States)

    1999-05-01

    Scanning Force Microscopy (SFM) has been used to quantitatively measure the elastic modulus, friction and hardness of polymer surfaces with special emphasis on polyethylene and polypropylene. In the experiments, tips of different radii of curvature ranging from 20 nm to 1000 nm have been used and the high pressure applied by the SFM have been observed to affect the values obtained in the measurements. The contact of the SFM tip with the polymer surface is explained by fitting the experimental curves to theoretical predictions of contact mechanics. Sum Frequency Generation (SFG) Vibrational Spectroscopy has been used to measure vibrational spectra of polymer surfaces in the vibrational range of 2700 to 3100 cm-1. Strong correlations are established between surface chemistry and surface structure as probed by SFG and mechanical properties measured by SFM on the surfaces. In these studies segregation of low surface energy moieties, from the bulk of the polymer to the surface have been studied. It was found that surface segregation occurs in miscible polymer blends and a small concentration of surface active polymer can be used to totally modify the surface properties of the blend. A novel high vacuum SFM was built to do temperature dependent measurements of mechanical changes occurring at the surface of polypropylene during the glass transition of the polymer. Using this instrument the modulus and friction of polypropylene was measured in the range of room temperature to ˜-60°C. An increase in the ordering of the backbone of the polymer chains below the glass transition measured by SFG correlates well with the increase in modulus measured on the same surface with SFM. Friction measurements have been done on polyethylene with three different instruments by applying loads ranging from nN to sub newton i.e. over eight orders of magnitude. Pressure and contact area effects were observed to play a significant role in determining the frictional response of the polymer

  7. Detecting Carbon in Carbon: Exploiting Differential Charging to Obtain Information on the Chemical Identity and Spatial Location of Carbon Nanotube Aggregates in Composites by Imaging X-ray Photoelectron Spectroscopy

    Science.gov (United States)

    Gorham, Justin M.; Osborn, William A.; Woodcock, Jeremiah W.; Scott, Keana C. K.; Heddleston, John M.; Walker, Angela R. Hight; Gilman, Jeffrey W

    2016-01-01

    To better assess risks associated with nano-enabled products including multiwalled carbon nanotubes (MWCNT) within polymer matrices, it is important to understand how MWCNT are dispersed throughout the composite. The current study presents a method which employs imaging X-ray photoelectron spectroscopy (XPS) to chemically detect spatially segregated MWCNT rich regions at an epoxy composites surface by exploiting differential charging. MWCNT do not charge due to high conductivity and have previously been shown to energetically separate from their insulating surroundings when characterized by XPS. XPS in imaging mode revealed that these conductive regions were spatially separated due to micrometer-scale MWCNT aggregation and poor dispersion during the formation of the composite. Three MWCNT concentrations were studied; (1, 4 and 5) % by mass MWCNT within an epoxy matrix. Images acquired in periodic energy intervals were processed using custom algorithms designed to efficiently extract spectra from regions of interest. As a result, chemical and electrical information on aggregate and non-aggregate portions of the composite was extracted. Raman imaging and scanning electron microscopy were employed as orthogonal techniques for validating this XPS-based methodology. Results demonstrate that XPS imaging of differentially charging MWCNT composite samples is an effective means for assessing dispersion quality. PMID:27765956

  8. In vivo single-voxel proton MR spectroscopy in the differentiation of high-grade gliomas and solitary metastases

    International Nuclear Information System (INIS)

    Fan, G.; Sun, B.; Wu, Z.; Guo, Q.; Guo, Y.

    2004-01-01

    AIM: To determine whether single-voxel proton magnetic resonance spectroscopy (1HMRS) could be used to differentiate gliomas from metastases on the basis of differences in metabolite levels in the different involved regions. MATERIALS AND METHODS: Twenty-two patients (age range from 32 to 62 years, with a median age of 46.7 years) with a solitary brain tumour (14 gliomas, eight metastases) underwent conventional, gadolinium-DTPA enhanced T1-weighted images, and 1HMRS before surgical resection. Spectra from the enhancing tumour, the peritumoural region, and normal brain were obtained from 1HMRS. A point resolved spectroscopy sequence was required for 1HMRS. The metabolites in the spectra include: N-acetylaspartate (NAA), choline (CHO), creatine compounds (CR), myo-inositol (MI), lactate (LAC), glutamate and glutamine (Glu-n). Relative concentrations of metabolites were related to the peak area, and expressed with reference to CR. Student's t-test was used to determine whether there was a statistically significant difference in relative metabolic ratios between high-grade gliomas and metastases. Meanwhile, 16 of all 22 patients were re-examined using magnetic resonance imaging (MRI) within 6 months of surgical resection. Recurrence was present in three patients (two gliomas, one metastasis). RESULTS: Of the 14 patients with gliomas, the peaks of NAA were reduced in three cases; the peaks of LAC, which were elevated, appeared as typical double-peaks in the peritumoural region in nine cases; the peaks of Glu-n, which were also elevated, had a zigzag appearance in seven cases. The peaks of MI were increased in the tumoural region in eight cases, and CHO levels were elevated in all 14 cases. Of the eight patients with metastases, Glu-n peaks in the tumoural region in three cases and CHO peaks in the tumoural region in four cases were elevated, respectively, while the peaks of CR were reduced in three cases, and the peaks of NAA were markedly reduced in four cases within

  9. Compatibilidad química del piracetam determinada por calorimetría diferencial de barrido Chemical compatibility of piracetam determined by differential scanning calorimetry

    Directory of Open Access Journals (Sweden)

    Luis Octavio Martínez Álvarez

    2013-03-01

    Full Text Available Introducción: en la primera etapa de preformulación de un medicamento se seleccionan los excipientes y es importante la realización de los estudios de compatibilidad química entre el ingrediente activo farmacéutico (IFA y excipientes. Una de las técnicas más rápidas para realizar dichos estudios es la Calorimetría diferencial de barrido (DSC, y como técnica complementaria la Termogravimetría (TG. Objetivo: empleando DSC y TG, se realiza un estudio de compatibilidad química entre IFA y excipientes preseleccionados, para comprobar la existencia o no de interacción química. Métodos: el equipo empleado fue el TA3000Mettler, aco­plado a la celda DSC20 y al horno TG50. El IFA utilizado fue Piracetam, y los excipientes: Kollidon VA 64, Estearato de magnesio, Celulosa microcristalina, Polietilenglicol 20 000 y Aerosil. Dichos excipientes se caracterizaron por DSC al igual que el IFA, al cual se le detectó la transición física de fusión. Para el estudio de compatibilidad se prepararon mezclas físicas binarias en una relación de concentración 1:1 Resultados: la figura 1 muestra la detección del punto de fusión por DSC del IFA. Se obtuvieron dos transiciones endotérmicas, comprobándose por TG cuál era la de fusión. La figura 2 muestra los termogramas de las mezclas formadas entre IFA y excipientes. Conclusiones: no se detectó aparición de nuevos picos, por lo que se infiere que no hay incompatibilidad química entre las sustancias estudiadas y se recomienda el uso de los excipientes para el desarrollo de la formulación farmacéutica.Introduction: the first phase of the drug preformulation comprises the selection of excipients and the conduction of studies on chemical compatibility between pharmacologically active ingredient and the excipients. One of the quickest techniques is the differential scanning calorimetry and the supplementary technique called thermogravimetic analysis. Objective: to conduct a chemical compatibility

  10. Influence of the thyroid remnant in the elevation of the serum thyroglobulin after thyroidectomy in differentiated thyroid carcinoma. Importance of the diagnostic iodine total-body scanning

    International Nuclear Information System (INIS)

    Caballero-Calabuig, Elisa; Cano-Terol, Carmen; Sopena-Monforte, Ramon; Reyes-Ojeda, Dolores; Abreu-Sanchez, Pedro; Ferrer-Rebolleda, Jose; Sopena-Novales, Pablo; Plancha-Mansanet, Carmen; Felix-Fontestad, Jesus

    2008-01-01

    Stimulated thyroglobulin (Tg) and 131 I total-body scan (TBS) have been the mainstays of differentiated thyroid carcinoma (DTC), but now diagnostic TBS has been eliminated from some follow-up protocols. Nevertheless, Tg can be negative in the presence of thyroid tissue, and moderately elevated Tg poses management problems. The purpose of this study was to check how many patients have Tg negative but visible thyroid tissue and if diagnostic TBS could be clinically useful. Retrospective review of 317 exams (stimulated Tg and TBS) of 128 patients with DTC. Patients with high-grade criteria and/or positive autoantibodies are excluded. Tg is considered positive if higher than the sensitivity level of the technique. TBS is positive if thyroid remnant, lymphatic node or metastases are detected. Results are classified in Tg and TBS concordant or discordant. Discordant 131 I TBS and Tg were found in 74/317 studies (23.3%), 48 (65%) being TBS positive and Tg negative. None of 128 patients had a first post-surgery negative scan, but 13 (10%) were Tg negative, even two patients with lymph node uptake. One year after radioiodine treatment, 26 out of 115 patients (initially Tg and TBS concordant positive) showed Tg negative and TBS still positive due to cervical remnants (20 patients), lymph node uptake (one) and metastasis (five); 20 patients remained Tg and TBS positive, but 14 of them only showed thyroid remnants. We propose to perform periodic diagnostic TBS to improve Tg specificity, at least while neck thyroid activity is detected, even if Tg is negative. (orig.)

  11. Clinical significance of the serum IL-2R level and Ga-67 scan findings in making a differential diagnosis between sarcoidosis and non-Hodgkin's lymphoma

    International Nuclear Information System (INIS)

    Kita, Tamotsu; Watanabe, Sadahiro; Yano, Fuzuki; Hayashi, Katsumi; Yamamoto, Masayoshi; Iwasaki, Yoshie; Kosuda, Shigeru

    2007-01-01

    The objective of this study was to compare the serum-soluble interleukin-2 receptor (sIL-2R) levels of non-Hodgkin's lymphoma patients and active sarcoidosis patients in relation to the 67 Ga scan findings. A total of 29 adenopathy patients suspected of having non-Hodgkin's lymphoma or sarcoidosis were enrolled in the study. All patients underwent a whole-body 67 Ga scan and single-photon emission computed tomography studies 48 h after intravenous injection of 67 Ga citrate. The sIL-2R levels were compared between the sarcoidosis patients and non-Hodgkin's lymphoma patients, the patients with and without the panda and/or lambda sign, the lymphoma patients with stage I/II disease and with stage III/IV disease, and the sarcoidosis patients and non-Hodgkin's lymphoma patients with stage III/IV disease. The range of the sIL-2R levels was 195-3750 U/ml in sarcoidosis and 240-62300 U/ml in non-Hodgkin's lymphoma. The sIL-2R levels of the six non-Hodgkin's lymphoma patients with stage III/IV disease were significantly higher than those of the 15 sarcoidosis patients (P<0.001). The sIL-2R levels of the sarcoidosis patients with the panda and/or lambda sign were significantly higher than those with neither sign (P<0.005). The sIL-2R levels of the non-Hodgkin's lymphoma patients with stage III/IV disease were significantly higher than those of the patients with stage I/II disease (P<0.005). Measurement of sIL-2R levels was sometimes useful in differentiating between sarcoidosis and stage III/IV non-Hodgkin's lymphoma, staging non-Hodgkin's lymphoma, and predicting the presence of the panda and/or lambda sign in sarcoidosis patients. (author)

  12. Characterization of Pegylated Liposomal Mitomycin C Lipid-Based Prodrug (Promitil) by High Sensitivity Differential Scanning Calorimetry and Cryogenic Transmission Electron Microscopy.

    Science.gov (United States)

    Wei, Xiaohui; Patil, Yogita; Ohana, Patricia; Amitay, Yasmine; Shmeeda, Hilary; Gabizon, Alberto; Barenholz, Yechezkel

    2017-12-04

    The effect of a lipidated prodrug of mitomycin C (MLP) on the membrane of a pegylated liposome formulation (PL-MLP), also known as Promitil, was characterized through high-sensitivity differential scanning calorimetry (DSC) and cryo-TEM. The thermodynamic analysis demonstrated that MLP led to the formation of heterogeneous domains in the membrane plane of PL-MLP. MLP concentrated in prodrug-rich domains, arranged in high-ordered crystal-like structures, as suggested by the sharp and high enthalpy endotherm in the first heating scanning. After thiolytic cleavage of mitomycin C from MLP by dithiothreitol (DTT) treatment, the crystal-like prodrug domain disappears and a homogeneous membrane with stronger lipid interactions and higher phase transition temperature compared with the blank (MLP-free) liposomes is observed by DSC. In parallel, the rod-like discoid liposomes and the "kissing liposomes" seen by cryo-TEM in the PL-MLP formulation disappear, and liposome mean size and polydispersity increase after DTT treatment. Both MLP and the residual postcleavage lipophilic moiety of the prodrug increased the rigidity of the liposome membrane as indicated by DSC. These results confirm that MLP is inserted in the PL-MLP liposome membrane via its lipophilic anchor, and its mitomycin C moiety located mainly at the region of the phospholipid glycerol backbone and polar headgroup. We hypothesize that π-π stacking between the planar aromatic rings of the mitomycin C moieties leads to the formation of prodrug-rich domains with highly ordered structure on the PL-MLP liposome membrane. This thermodynamically stable conformation may explain the high stability of the PL-MLP formulation. These results also provide us with an interesting example of the application of high sensitivity DSC in understanding the composition-structure-behavior dynamics of liposomal nanocarriers having a lipid-based drug as pharmaceutical ingredient.

  13. Two instruments based on differential optical absorption spectroscopy (DOAS) to measure accurate ammonia concentrations in the atmosphere

    Science.gov (United States)

    Volten, H.; Bergwerff, J. B.; Haaima, M.; Lolkema, D. E.; Berkhout, A. J. C.; van der Hoff, G. R.; Potma, C. J. M.; Wichink Kruit, R. J.; van Pul, W. A. J.; Swart, D. P. J.

    2012-02-01

    We present two Differential Optical Absorption Spectroscopy (DOAS) instruments built at RIVM: the RIVM DOAS and the miniDOAS. Both instruments provide virtually interference-free measurements of NH3 concentrations in the atmosphere, since they measure over an open path, without suffering from inlet problems or interference problems by ammonium aerosols dissociating on tubes or filters. They measure concentrations up to at least 200 μg m-3, have a fast response, low maintenance demands, and a high up-time. The RIVM DOAS has a high accuracy of typically 0.15 μg m-3 for ammonia for 5-min averages and over a total light path of 100 m. The miniDOAS has been developed for application in measurement networks such as the Dutch National Air Quality Monitoring Network (LML). Compared to the RIVM DOAS it has a similar accuracy, but is significantly reduced in size, costs, and handling complexity. The RIVM DOAS and miniDOAS results showed excellent agreement (R2 = 0.996) during a field measurement campaign in Vredepeel, the Netherlands. This measurement site is located in an agricultural area and is characterized by highly variable, but on average high ammonia concentrations in the air. The RIVM-DOAS and miniDOAS results were compared to the results of the AMOR instrument, a continuous-flow wet denuder system, which is currently used in the LML. Averaged over longer time spans of typically a day, the (mini)DOAS and AMOR results agree reasonably well, although an offset of the AMOR values compared to the (mini)DOAS results exists. On short time scales, the (mini)DOAS shows a faster response and does not show the memory effects due to inlet tubing and transport of absorption fluids encountered by the AMOR. Due to its high accuracy, high uptime, low maintenance and its open path, the (mini)DOAS shows a good potential for flux measurements by using two (or more) systems in a gradient set-up and applying the aerodynamic gradient technique.

  14. Differential optical absorption spectroscopy (DOAS and air mass factor concept for a multiply scattering vertically inhomogeneous medium: theoretical consideration

    Directory of Open Access Journals (Sweden)

    V. V. Rozanov

    2010-06-01

    Full Text Available The Differential Optical Absorption Spectroscopy (DOAS technique is widely used to retrieve amounts of atmospheric species from measurements of the direct solar light transmitted through the Earth's atmosphere as well as of the solar light scattered in the atmosphere or reflected from the Earth's surface. For the transmitted direct solar light the theoretical basis of the DOAS technique represented by the Beer-Lambert law is well studied. In contrast, scarcely investigated is the theoretical basis and validity range of the DOAS method for those cases where the contribution of the multiple scattering processes is not negligible. Our study is intended to fill this gap by means of a theoretical investigation of the applicability of the DOAS technique for the retrieval of amounts of atmospheric species from observations of the scattered solar light with a non-negligible contribution of the multiple scattering.

    Starting from the expansion of the intensity logarithm in the functional Taylor series we formulate the general form of the DOAS equation. The thereby introduced variational derivative of the intensity logarithm with respect to the variation of the gaseous absorption coefficient, which is often referred to as the weighting function, is demonstrated to be closely related to the air mass factor. Employing some approximations we show that the general DOAS equation can be rewritten in the form of the weighting function (WFDOAS, the modified (MDOAS, and the standard DOAS equations. For each of these forms a specific equation for the air mass factor follows which, in general, is not suitable for other forms of the DOAS equation. Furthermore, the validity range of the standard DOAS equation is quantitatively investigated using a suggested criterion of a weak absorption.

    The results presented in this study are intended to provide a basis for a better understanding of the applicability range of different forms of the DOAS equation as

  15. Two instruments based on differential optical absorption spectroscopy (DOAS to measure accurate ammonia concentrations in the atmosphere

    Directory of Open Access Journals (Sweden)

    H. Volten

    2012-02-01

    Full Text Available We present two Differential Optical Absorption Spectroscopy (DOAS instruments built at RIVM: the RIVM DOAS and the miniDOAS. Both instruments provide virtually interference-free measurements of NH3 concentrations in the atmosphere, since they measure over an open path, without suffering from inlet problems or interference problems by ammonium aerosols dissociating on tubes or filters. They measure concentrations up to at least 200 μg m−3, have a fast response, low maintenance demands, and a high up-time. The RIVM DOAS has a high accuracy of typically 0.15 μg m−3 for ammonia for 5-min averages and over a total light path of 100 m. The miniDOAS has been developed for application in measurement networks such as the Dutch National Air Quality Monitoring Network (LML. Compared to the RIVM DOAS it has a similar accuracy, but is significantly reduced in size, costs, and handling complexity. The RIVM DOAS and miniDOAS results showed excellent agreement (R2 = 0.996 during a field measurement campaign in Vredepeel, the Netherlands. This measurement site is located in an agricultural area and is characterized by highly variable, but on average high ammonia concentrations in the air. The RIVM-DOAS and miniDOAS results were compared to the results of the AMOR instrument, a continuous-flow wet denuder system, which is currently used in the LML. Averaged over longer time spans of typically a day, the (miniDOAS and AMOR results agree reasonably well, although an offset of the AMOR values compared to the (miniDOAS results exists. On short time scales, the (miniDOAS shows a faster response and does not show the memory effects due to inlet tubing and transport of absorption fluids encountered by the AMOR. Due to its high accuracy, high uptime, low maintenance and its open path, the (miniDOAS shows a good potential for flux measurements by using two (or more systems in a gradient set-up and applying the

  16. ceramics by differential scanning calorimetry

    Indian Academy of Sciences (India)

    Administrator

    tilled water. These solutions were mixed, stirred, filtered and slowly added into a dilute ammonium hydrate solu- tion to obtain gel-like precipitates. These gels were washed with distilled water until pH = 7 and then washed several times in analytically ... chromate, barium carbonate and strontium carbonate sup- plied by the ...

  17. Differential Multiphoton Laser Scanning Microscopy.

    Science.gov (United States)

    Field, Jeffrey J; Sheetz, Kraig E; Chandler, Eric V; Hoover, Erich E; Young, Michael D; Ding, Shi-You; Sylvester, Anne W; Kleinfeld, David; Squier, Jeff A

    2012-01-01

    Multifocal multiphoton microscopy (MMM) in the biological and medical sciences has become an important tool for obtaining high resolution images at video rates. While current implementations of MMM achieve very high frame rates, they are limited in their applicability to essentially those biological samples that exhibit little or no scattering. In this paper, we report on a method for MMM in which imaging detection is not necessary (single element point detection is implemented), and is therefore fully compatible for use in imaging through scattering media. Further, we demonstrate that this method leads to a new type of MMM wherein it is possible to simultaneously obtain multiple images and view differences in excitation parameters in a single shot.

  18. Raman Spectroscopy Differentiates Each Tissue From the Skin to the Spinal Cord: A Novel Method for Epidural Needle Placement?

    Science.gov (United States)

    Anderson, T. Anthony; Kang, Jeon Woong; Gubin, Tatyana; Dasari, Ramachandra R.; So, Peter T. C.

    2016-01-01

    BACKGROUND Neuraxial anesthesia and epidural steroid injection techniques require precise anatomical targeting to ensure successful and safe analgesia. Previous studies suggest that only some of the tissues encountered during these procedures can be identified by spectroscopic methods, and no previous study has investigated the use of Raman, diffuse reflectance, and fluorescence spectroscopies. The authors hypothesized that real-time needle-tip spectroscopy may aid epidural needle placement and tested the ability of spectroscopy to distinguish each of the tissues in the path of neuraxial needles. METHODS For comparison of detection methods, the spectra of individual, dissected ex vivo paravertebral and neuraxial porcine tissues were collected using Raman spectroscopy (RS), diffuse reflectance spectroscopy (DRS), and fluorescence spectroscopy (FS). Real-time spectral guidance was tested using a 2 mm inner diameter fiber optic probe-in-needle device. Raman spectra were collected during the needle’s passage through intact paravertebral and neuraxial porcine tissue and analyzed afterward. The RS tissue signatures were verified as mapping to individual tissue layers using histochemical staining and widefield microscopy. RESULTS Raman spectroscopy revealed a unique spectrum for all ex vivo paravertebral and neuraxial tissue layers; DRS and FS spectra were not distinct for all tissues. Moreover, when accounting for the expected order of tissues, real-time Raman spectra recorded during needle insertion also permitted identification of each paravertebral and neuraxial porcine tissue. CONCLUSIONS This study demonstrates Raman spectroscopy can distinguish the tissues encountered during epidural needle insertion. This technology may prove useful during needle placement by providing evidence of its anatomical localization. PMID:27466032

  19. Dissecting the salt dependence of the Tus-Ter protein-DNA complexes by high-throughput differential scanning fluorimetry of a GFP-tagged Tus.

    Science.gov (United States)

    Moreau, Morgane J J; Schaeffer, Patrick M

    2013-12-01

    The analysis of the salt dependence of protein-DNA complexes provides useful information about the non-specific electrostatic and sequence-specific parameters driving complex formation and stability. The differential scanning fluorimetry of GFP-tagged protein (DSF-GTP) assay has been geared with an automatic Tm peak recognition system and was applied for the high-throughput (HT) determination of salt-induced effects on the GFP-tagged DNA replication protein Tus in complex with various Ter and Ter-lock sequences. The system was designed to generate two-dimensional heat map profiles of Tus-GFP protein stability allowing for a comparative study of the effect of eight increasing salt concentrations on ten different Ter DNA species at once. The data obtained with the new HT DSF-GTP allowed precise dissection of the non-specific electrostatic and sequence-specific parameters driving Tus-Ter and Tus-Ter-lock complex formation and stability. The major factor increasing the thermal resistance of Tus-Ter-lock complexes in high-salt is the formation of the TT-lock, e.g. a 10-fold higher Kspe was obtained for Tus-GFP:Ter-lockB than for Tus-GFP:TerB. It is anticipated that the system can be easily adapted for the study of other protein-DNA complexes.

  20. The use of Rheology Combined with Differential Scanning Calorimetry to Elucidate the Granulation Mechanism of an Immiscible Formulation During Continuous Twin-Screw Melt Granulation.

    Science.gov (United States)

    Monteyne, Tinne; Heeze, Liza; Mortier, Severine Therese F C; Oldörp, Klaus; Cardinaels, Ruth; Nopens, Ingmar; Vervaet, Chris; Remon, Jean-Paul; De Beer, Thomas

    2016-10-01

    Twin screw hot melt granulation (TS HMG) is a valuable, but still unexplored alternative to continuous granulation of moisture sensitive drugs. However, knowledge of the material behavior during TS HMG is crucial to optimize the formulation, process and resulting granule properties. The aim of this study was to evaluate the agglomeration mechanism during TS HMG using a rheometer in combination with differential scanning calorimetry (DSC). An immiscible drug-binder formulation (caffeine-Soluplus(®)) was granulated via TS HMG in combination with thermal and rheological analysis (conventional and Rheoscope), granule characterization and Near Infrared chemical imaging (NIR-CI). A thin binder layer with restricted mobility was formed on the surface of the drug particles during granulation and is covered by a second layer with improved mobility when the Soluplus(®) concentration exceeded 15% (w/w). The formation of this second layer was facilitated at elevated granulation temperatures and resulted in smaller and more spherical granules. The combination of thermal and rheological analysis and NIR-CI images was advantageous to develop in-depth understanding of the agglomeration mechanism during continuous TS HMG and provided insight in the granule properties as function of process temperature and binder concentration.

  1. Structure, activity and thermostability investigations of OXA-163, OXA-181 and OXA-245 using biochemical analysis, crystal structures and differential scanning calorimetry analysis.

    Science.gov (United States)

    Lund, Bjarte Aarmo; Thomassen, Ane Molden; Carlsen, Trine Josefine Olsen; Leiros, Hanna Kirsti S

    2017-10-01

    The first crystal structures of the class D β-lactamases OXA-181 and OXA-245 were determined to 2.05 and 2.20 Å resolution, respectively; in addition, the structure of a new crystal form of OXA-163 was resolved to 2.07 Å resolution. All of these enzymes are OXA-48-like and have been isolated from different clinical Klebsiella pneumoniae strains and also from other human pathogens such as Pseudomonas aeruginosa and Escherichia coli. Here, enzyme kinetics and thermostability studies are presented, and the new crystal structures are used to explain the observed variations. OXA-245 had the highest melting point (T m = 55.8°C), as determined by differential scanning calorimetry, compared with OXA-163 (T m = 49.4°C) and OXA-181 (T m = 52.6°C). The differences could be explained by the loss of two salt bridges in OXA-163, and an overall decrease in the polarity of the surface of OXA-181 compared with OXA-245.

  2. Kinetics of Cold-Cap Reactions for Vitrification of Nuclear Waste Glass Based on Simultaneous Differential Scanning Calorimetry - Thermogravimetry (DSC-TGA) and Evolved Gas Analysis (EGA)

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Carmen P.; Pierce, David A.; Schweiger, Michael J.; Kruger, Albert A.; Chun, Jaehun; Hrma, Pavel R.

    2013-12-03

    For vitrifying nuclear waste glass, the feed, a mixture of waste with glass-forming and modifying additives, is charged onto the cold cap that covers 90-100% of the melt surface. The cold cap consists of a layer of reacting molten glass floating on the surface of the melt in an all-electric, continuous glass melter. As the feed moves through the cold cap, it undergoes chemical reactions and phase transitions through which it is converted to molten glass that moves from the cold cap into the melt pool. The process involves a series of reactions that generate multiple gases and subsequent mass loss and foaming significantly influence the mass and heat transfers. The rate of glass melting, which is greatly influenced by mass and heat transfers, affects the vitrification process and the efficiency of the immobilization of nuclear waste. We studied the cold-cap reactions of a representative waste glass feed using both the simultaneous differential scanning calorimetry thermogravimetry (DSC-TGA) and the thermogravimetry coupled with gas chromatography-mass spectrometer (TGA-GC-MS) as complementary tools to perform evolved gas analysis (EGA). Analyses from DSC-TGA and EGA on the cold-cap reactions provide a key element for the development of an advanced cold-cap model. It also helps to formulate melter feeds for higher production rate.

  3. Characterization of thermal reaction of aluminum/copper (II) oxide/poly(tetrafluoroethene) nanocomposite by thermogravimetric analysis, differential scanning calorimetry, mass spectrometry and X-ray diffraction

    International Nuclear Information System (INIS)

    Li, Xiangyu; Yang, Hongtao; Li, Yan-chun

    2015-01-01

    Highlights: • The thermal reaction properties of the Al/CuO/PTFE nanocomposite were investigated. • The Al/PTFE and CuO/PTFE nanocomposites were prepared and tested for comparison. • TG/DSC–MS and XRD analysis were performed. • PTFE is oxidizing Al and reducing CuO during the thermal decomposition. - Abstract: The application of fluoropolymers as reactive agent in energetic materials have attracted significant interest recently. In this study, the thermal reaction properties of the aluminum nanoparticles/copper (II) oxide nanoparticles/poly(tetrafluoroethene) (Al-NPs/CuO-NPs/PTFE) nanocomposite (mass ratio of Al-NPs/CuO-NPs/PTFE = 20/60/20) were investigated by means of thermogravimetry/differential scanning calorimetry–mass spectrometry (TG/DSC–MS) and X-ray diffraction (XRD) analyses. The Al-NPs/PTFE (mass ratio of Al-NPs/PTFE = 50/50) and CuO-NPs/PTFE (mass ratio of CuO-NPs/PTFE = 75/25) nanocomposites were also prepared and tested for comparison. It is observed that PTFE is acting as both oxidizer and reducer during the thermal decomposition process of Al-NPs/CuO-NPs/PTFE nanocomposites. Before 615 °C, PTFE is oxidized by CuO-NPs and oxidizing Al-NPs, resulting mass reduction. After 615 °C, the excessive aluminum and copper (I)/copper (II) oxide will proceed the exothermic condensed phase reaction.

  4. Kinetics of Cold-Cap Reactions for Vitrification of Nuclear Waste Glass Based on Simultaneous Differential Scanning Calorimetry - Thermogravimetry (DSC-TGA) and Evolved Gas Analysis (EGA)

    International Nuclear Information System (INIS)

    Rodriguez, Carmen P.; Pierce, David A.; Schweiger, Michael J.; Kruger, Albert A.; Chun, Jaehun; Hrma, Pavel R.

    2013-01-01

    For vitrifying nuclear waste glass, the feed, a mixture of waste with glass-forming and modifying additives, is charged onto the cold cap that covers 90-100% of the melt surface. The cold cap consists of a layer of reacting molten glass floating on the surface of the melt in an all-electric, continuous glass melter. As the feed moves through the cold cap, it undergoes chemical reactions and phase transitions through which it is converted to molten glass that moves from the cold cap into the melt pool. The process involves a series of reactions that generate multiple gases and subsequent mass loss and foaming significantly influence the mass and heat transfers. The rate of glass melting, which is greatly influenced by mass and heat transfers, affects the vitrification process and the efficiency of the immobilization of nuclear waste. We studied the cold-cap reactions of a representative waste glass feed using both the simultaneous differential scanning calorimetry thermogravimetry (DSC-TGA) and the thermogravimetry coupled with gas chromatography-mass spectrometer (TGA-GC-MS) as complementary tools to perform evolved gas analysis (EGA). Analyses from DSC-TGA and EGA on the cold-cap reactions provide a key element for the development of an advanced cold-cap model. It also helps to formulate melter feeds for higher production rate

  5. Characteristics of rose hip (Rosa canina L.) cold-pressed oil and its oxidative stability studied by the differential scanning calorimetry method.

    Science.gov (United States)

    Grajzer, Magdalena; Prescha, Anna; Korzonek, Katarzyna; Wojakowska, Anna; Dziadas, Mariusz; Kulma, Anna; Grajeta, Halina

    2015-12-01

    Two new commercially available high linolenic oils, pressed at low temperature from rose hip seeds, were characterised for their composition, quality and DPPH radical scavenging activity. The oxidative stability of oils was assessed using differential scanning calorimetry (DSC). Phytosterols, tocopherols and carotenoids contents were up to 6485.4; 1124.7; and 107.7 mg/kg, respectively. Phenolic compounds determined for the first time in rose hip oil totalled up to 783.55 μg/kg, with a predominant presence of p-coumaric acid methyl ester. Antiradical activity of the oils reached up to 3.00 mM/kg TEAC. The acid, peroxide and p-anisidine values as well as iron and copper contents indicated good quality of the oils. Relatively high protection against oxidative stress in the oils seemed to be a result of their high antioxidant capacity and the level of unsaturation of fatty acids. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Optical methods and differential scanning calorimetry as a potential tool for discrimination of olive oils (extra virgin and mix with vegetable oils)

    Science.gov (United States)

    Nikolova, Kr.; Yovcheva, T.; Marudova, M.; Eftimov, T.; Bodurov, I.; Viraneva, A.; Vlaeva, I.

    2016-03-01

    Eleven samples from olive oil have been investigated using four physical methods - refractive index measurement, fluorescence spectra, color parameters and differential scanning colorimetry. In pomace olive oil (POO) and extra virgin olive oil (EVOO) the oleic acid (65.24 %-78.40 %) predominates over palmitic (10.47 %-15.07 %) and linoleic (5.26 %-13.92 %) acids. The fluorescence spectra contain three peaks related to oxidation products at about λ = (500-540) nm, chlorophyll content at about λ = (675-680) nm and non determined pigments at λ = (700-750) nm. The melting point for EVOO and POO is between -1 °C and -6 °C. In contrast, the salad olive oils melt between -24 °C and -30 °C. The refractive index for EVOO is lower than that for mixed olive oils. The proposed physical methods could be used for fast and simple detection of vegetable oils in EVOO without use of chemical substances. The experimental results are in accordance with those obtained by chemical analysis.

  7. Preparation and phase behaviour of surface-active pharmaceuticals: self-assembly of DNA and surfactants with membranes. Differential adiabatic scanning microcalorimetric study.

    Science.gov (United States)

    Süleymanoğlu, Erhan

    2005-08-01

    Some energetics issues relevant to preparation and surface characterization of zwitterionic phospholipid-DNA self-assemblies, as alternative models of the currently used problematic lipoplexes are presented. Nucleic acid compaction capacities of Mg(2+) and N-alkyl-N,N,N-trimetylammonium ions (C(n)TMA, n=12) were compared, with regard to surface interaction with unilamellar vesicles. Differential adiabatic scanning microcalorimetric measurements of synthetic phosphatidylcholine liposomes and calf thymus DNA and their ternary complexes with Mg(2+) and C(12)TMA, were employed for deduction of the thermodynamic model describing their structural transitions. Small monodisperce and highly stable complexes are established after precompaction of DNA with detergent, followed by addition of liposomes. In contrast, divalent metal cation-mediated aggregation of vesicles either leads to heterogeneous multilamellar DNA-lipid arrangements, or to DNA-induced bilayer destabilization and lipid fusion. Possible dependence of the cellular internalization and gene transfection efficiency on the structure and physicochemical properties of DNA-Mg(2+)-liposomes or DNA-cationic surfactant-liposome systems is emphasized by proposing the structure of their molecular self-organizations with further implications in gene transfer research.

  8. Are All-Solid-State Lithium-Ion Batteries Really Safe?-Verification by Differential Scanning Calorimetry with an All-Inclusive Microcell.

    Science.gov (United States)

    Inoue, Takao; Mukai, Kazuhiko

    2017-01-18

    Although all-solid-state lithium-ion batteries (ALIBs) have been believed as the ultimate safe battery, their true character has been an enigma so far. In this paper, we developed an all-inclusive-microcell (AIM) for differential scanning calorimetry (DSC) analysis to clarify the degree of safety (DOS) of ALIBs. Here AIM possesses all the battery components to work as a battery by itself, and DOS is determined by the total heat generation ratio (ΔH) of ALIB compared with the conventional LIB. When DOS = 100%, the safety of ALIB is exactly the same as that of LIB; when DOS = 0%, ALIB reaches the ultimate safety. We investigated two types of LIB-AIM and three types of ALIB-AIM. Surprisingly, all the ALIBs exhibit one or two exothermic peaks above 250 °C with 20-30% of DOS. The exothermic peak is attributed to the reaction between the released oxygen from the positive electrode and the Li metal in the negative electrode. Hence, ALIBs are found to be flammable as in the case of LIBs. We also attempted to improve the safety of ALIBs and succeeded in decreasing the DOS down to ∼16% by incorporating Ketjenblack into the positive electrode as an oxygen scavenger. Based on ΔH as a function of voltage window, a safety map for LIBs and ALIBs is proposed.

  9. Preliminary Clinical Validation of a Differential Correction Method for Improving Measurement Accuracy in Noninvasive Measurement of Blood Glucose Using Near-Infrared Spectroscopy.

    Science.gov (United States)

    Han, Guang; Yu, Xuyao; Xia, Dandan; Liu, Rong; Liu, Jin; Xu, Kexin

    2017-09-01

    One of the main challenges in the noninvasive sensing of blood glucose by near-infrared (NIR) spectroscopy is the background variations from light source drift, sweating, and temperature change at the human-machine interface. In this paper, a differential correction method based on the spectra from the floating-reference position and measuring position is proposed to eliminate these spectral variations from background interferences. Its effectiveness was validated by in vitro and in vivo experiments in which the diffuse reflectance of intralipid solutions and human skin was collected at the source distances of 0.6 mm and 2 mm by the custom-built system with six super-luminescent emitting diodes (SLEDs) light source. The results showed that, for the in vitro experiments of intralipid solutions, the coefficients of variations of diffuse reflectance decreased by 20.5% under all the six wavelengths after differential correction. For the in vivo experiments of oral glucose tolerance tests (OGTTs), partial least squares (PLS) regression models between glucose concentrations and the diffuse reflectance from palm skin were built, and the root mean square error of cross validation (RMSECV) decreased by 38.0% on average after the differential correction. Further, the spectra of the oral water tolerance tests (OWTTs) were collected for correlation with glucose concentration in OGTTs, and their correlation coefficients (R) decreased by 35.0% on average after the differential correction. Therefore, this differential correction method based on the spectra from the floating-reference position and measuring position can weaken the influence of background variations on the NIR spectroscopy and has promising potential in in vivo detection, especially for noninvasive blood glucose measurement.

  10. Influência de alguns parâmetros experimentais nos resultados de análises calorimétricas diferenciais - DSC Influence of some experimental parameters on the results of differential scanning calorimetry - DSC.

    OpenAIRE

    Cláudia Bernal; Andréa Boldarini Couto; Susete Trazzi Breviglieri; Éder Tadeu Gomes Cavalheiro

    2002-01-01

    A series of experiments were performed in order to demonstrate to undergraduate students or users of the differential scanning calorimetry (DSC), that several factors can influence the qualitative and quantitative aspects of DSC results. Saccharin, an artificial sweetner, was used as a probe and its thermal behavior is also discussed on the basis of thermogravimetric (TG) and DSC curves.

  11. AquaScan: A miniaturized UV/VIS/IR hyperspectral imager for autonomous airborne and underwater imaging spectroscopy of coastal & oceanic environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The AquaScan, a miniaturized UV/VIS/NIR hyperspectral imager will be built for deployment on a UAV or small manned aircraft for ocean coastal remote sensing...

  12. Differentiation and classification of bacteria using vancomycin functionalized silver nanorods array based surface-enhanced raman spectroscopy an chemometric analysis

    Science.gov (United States)

    The intrinsic surface-enhanced Raman scattering (SERS) was used for differentiating and classifying bacterial species with chemometric data analysis. Such differentiation has often been conducted with an insufficient sample population and strong interference from the food matrices. To address these ...

  13. Nuclear Scans

    Science.gov (United States)

    Nuclear scans use radioactive substances to see structures and functions inside your body. They use a special ... images. Most scans take 20 to 45 minutes. Nuclear scans can help doctors diagnose many conditions, including ...

  14. Synthesis and characterization of Ni0.4Co2.6O4 spinel mixed oxides powder: study of its surface properties by voltammetry, x-ray, ftir, UV-VIS-NIR spectroscopy and scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Makhtar Guene

    2005-12-01

    Full Text Available Electrochemical studies were carried out on Ni0.4Co2.6O4 powders prepared by sol-gel via propionic acid method using cyclic and steady state voltammetries. The oxide surface was characterized by scanning electron microscopy (SEM, X-ray diffraction, UV-vis-NIR and FTIR spectroscopies. The results showed that the formation of homogeneous oxide with a single spinel phase occurred at 350°C. The surface redox couple NiOOH/Ni(OH2 is confined on the surface material l.

  15. Time dependence of the natural passivation process on AISI 304 in an alkaline medium: Atomic force microscopy and scanning Kelvin probe force microscopy as additional tools to electrochemical impedance spectroscopy

    Science.gov (United States)

    Benaioun, N. E.; Maafa, I.; Florentin, A.; Denys, E.; Hakiki, N. E.; Moulayat, N.; Bubendorff, J. L.

    2018-04-01

    Thin surface films formed on AISI 304 samples in an alkaline solution of pH = 13 are studied by atomic force microscopy (AFM), scanning Kelvin probe force microscopy (SKPFM) and electrochemical impedance spectroscopy (EIS) as a function of immersion time. The results reveal that changes on EIS diagrams correspond to topographical modifications on the sample surface as shown by AFM. Both techniques are therefore complementary. The oxide layer is chemically homogenous as shown by SKPFM imaging and our ultra-thin passive layer is an efficient barrier against corrosion.

  16. Grain boundary engineering of La{sub 0.7} Sr{sub 0.3} MnO{sub 3} films on silicon substrate: Scanning Tunneling Microscopy-Spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Anupama [Department of Applied Physics, Defence Institute of Advanced Technology (DU), Girinagar, Pune 411025 (India); Nori, Rajashree [Centre of Excellence in Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology (IIT Bombay), Mumbai 400076 (India); Dhobale, Sandip [Department of Applied Physics, Defence Institute of Advanced Technology (DU), Girinagar, Pune 411025 (India); Ramgopal Rao, V. [Centre of Excellence in Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology (IIT Bombay), Mumbai 400076 (India); Kale, S.N., E-mail: sangeetakale2004@gmail.com [Department of Applied Physics, Defence Institute of Advanced Technology (DU), Girinagar, Pune 411025 (India); Datar, Suwarna, E-mail: suwarna.datar@gmail.com [Department of Applied Physics, Defence Institute of Advanced Technology (DU), Girinagar, Pune 411025 (India)

    2014-09-01

    We employed a Scanning Tunnelling Microscope (STM) to study the surface topography and spatially resolved local electronic properties like local density of states (LDOS) of nanostructured films of La{sub 0.7} Sr{sub 0.3} MnO{sub 3} (LSMO). The nanostructured thin films of LSMO on silicon substrate were prepared using Pulsed Laser Deposition (PLD) technique. The deposition conditions were tuned to yield two different morphologies; one with uniform columnar closely packed islands and other with larger grain distribution in random fashion. The Scanning Tunnelling Spectroscopy (STS) revealed the extent of variation of density of states (DOS) near the Fermi level. From the spectroscopic features obtained we found the occurrence of phase separation between conducting and semiconducting domains and its possible correlation with the properties of the system. Semiconducting nature was observed at the grain boundaries, which could be extremely promising in futuristic nano-devices.

  17. Prefrontal activation during inhibitory control measured by near-infrared spectroscopy for differentiating between autism spectrum disorders and attention deficit hyperactivity disorder in adults.

    Science.gov (United States)

    Ishii-Takahashi, Ayaka; Takizawa, Ryu; Nishimura, Yukika; Kawakubo, Yuki; Kuwabara, Hitoshi; Matsubayashi, Junko; Hamada, Kasumi; Okuhata, Shiho; Yahata, Noriaki; Igarashi, Takashi; Kawasaki, Shingo; Yamasue, Hidenori; Kato, Nobumasa; Kasai, Kiyoto; Kano, Yukiko

    2014-01-01

    The differential diagnosis of autism spectrum disorders (ASDs) and attention deficit hyperactivity disorder (ADHD) based solely on symptomatic and behavioral assessments can be difficult, even for experts. Thus, the development of a neuroimaging marker that differentiates ASDs from ADHD would be an important contribution to this field. We assessed the differences in prefrontal activation between adults with ASDs and ADHD using an entirely non-invasive and portable neuroimaging tool, near-infrared spectroscopy. This study included 21 drug-naïve adults with ASDs, 19 drug-naïve adults with ADHD, and 21 healthy subjects matched for age, sex, and IQ. Oxygenated hemoglobin concentration changes in the prefrontal cortex were assessed during a stop signal task and a verbal fluency task. During the stop signal task, compared to the control group, the ASDs group exhibited lower activation in a broad prefrontal area, whereas the ADHD group showed underactivation of the right premotor area, right presupplementary motor area, and bilateral dorsolateral prefrontal cortices. Significant differences were observed in the left ventrolateral prefrontal cortex between the ASDs and ADHD groups during the stop signal task. The leave-one-out cross-validation method using mean oxygenated hemoglobin changes yielded a classification accuracy of 81.4% during inhibitory control. These results were task specific, as the brain activation pattern observed during the verbal fluency task did not differentiate the ASDs and ADHD groups significantly. This study therefore provides evidence of a difference in left ventrolateral prefrontal activation during inhibitory control between adults with ASDs and ADHD. Thus, near-infrared spectroscopy may be useful as an auxiliary tool for the differential diagnosis of such developmental disorders.

  18. Prefrontal activation during inhibitory control measured by near-infrared spectroscopy for differentiating between autism spectrum disorders and attention deficit hyperactivity disorder in adults

    Directory of Open Access Journals (Sweden)

    Ayaka Ishii-Takahashi

    2014-01-01

    Full Text Available The differential diagnosis of autism spectrum disorders (ASDs and attention deficit hyperactivity disorder (ADHD based solely on symptomatic and behavioral assessments can be difficult, even for experts. Thus, the development of a neuroimaging marker that differentiates ASDs from ADHD would be an important contribution to this field. We assessed the differences in prefrontal activation between adults with ASDs and ADHD using an entirely non-invasive and portable neuroimaging tool, near-infrared spectroscopy. This study included 21 drug-naïve adults with ASDs, 19 drug-naïve adults with ADHD, and 21 healthy subjects matched for age, sex, and IQ. Oxygenated hemoglobin concentration changes in the prefrontal cortex were assessed during a stop signal task and a verbal fluency task. During the stop signal task, compared to the control group, the ASDs group exhibited lower activation in a broad prefrontal area, whereas the ADHD group showed underactivation of the right premotor area, right presupplementary motor area, and bilateral dorsolateral prefrontal cortices. Significant differences were observed in the left ventrolateral prefrontal cortex between the ASDs and ADHD groups during the stop signal task. The leave-one-out cross-validation method using mean oxygenated hemoglobin changes yielded a classification accuracy of 81.4% during inhibitory control. These results were task specific, as the brain activation pattern observed during the verbal fluency task did not differentiate the ASDs and ADHD groups significantly. This study therefore provides evidence of a difference in left ventrolateral prefrontal activation during inhibitory control between adults with ASDs and ADHD. Thus, near-infrared spectroscopy may be useful as an auxiliary tool for the differential diagnosis of such developmental disorders.

  19. Gain-compensation Methodology for a Sinusoidal Scan of a Galvanometer Mirror in Proportional-Integral-Differential Control Using Pre-emphasis Techniques.

    Science.gov (United States)

    Hayakawa, Tomohiko; Watanabe, Takanoshin; Senoo, Taku; Ishikawa, Masatoshi

    2017-04-04

    Galvanometer mirrors are used for optical applications such as target tracking, drawing, and scanning control because of their high speed and accuracy. However, the responsiveness of a galvanometer mirror is limited by its inertia; hence, the gain of a galvanometer mirror is reduced when the control path is steep. In this research, we propose a method to extend the corresponding frequency using a pre-emphasis technique to compensate for the gain reduction of galvanometer mirrors in sine-wave path tracking using proportional-integral-differential (PID) control. The pre-emphasis technique obtains an input value for a desired output value in advance. Applying this method to control the galvanometer mirror, the raw gain of a galvanometer mirror in each frequency and amplitude for sine-wave path tracking using a PID controller was calculated. Where PID control is not effective, maintaining a gain of 0 dB to improve the trajectory tracking accuracy, it is possible to expand the speed range in which a gain of 0 dB can be obtained without tuning the PID control parameters. However, if there is only one frequency, amplification is possible with a single pre-emphasis coefficient. Therefore, a sine wave is suitable for this technique, unlike triangular and sawtooth waves. Hence, we can adopt a pre-emphasis technique to configure the parameters in advance, and we need not prepare additional active control models and hardware. The parameters are updated immediately within the next cycle because of the open loop after the pre-emphasis coefficients are set. In other words, to regard the controller as a black box, we need to know only the input-to-output ratio, and detailed modeling is not required. This simplicity allows our system to be easily embedded in applications. Our method using the pre-emphasis technique for a motion-blur compensation system and the experiment conducted to evaluate the method are explained.

  20. Synergistic use of Knudsen effusion quadrupole mass spectrometry, solid-state galvanic cell and differential scanning calorimetry for thermodynamic studies on lithium aluminates

    Science.gov (United States)

    Rakshit, S. K.; Naik, Y. P.; Parida, S. C.; Dash, Smruti; Singh, Ziley; Sen, B. K.; Venugopal, V.

    2008-06-01

    Three ternary oxides LiAl 5O 8(s), LiAlO 2(s) and Li 5AlO 4(s) in the system Li-Al-O were prepared by solid-state reaction route and characterized by X-ray powder diffraction method. Equilibrium partial pressure of CO 2(g) over the three-phase mixtures {LiAl 5O 8(s)+Li 2CO 3(s)+5Al 2O 3(s)}, {LiAl 5O 8(s)+5LiAlO 2(s)+2Li 2CO 3(s)} and {LiAlO 2(s)+Li 5AlO 4(s)+2Li 2CO 3(s)} were measured using Knudsen effusion quadrupole mass spectrometry (KEQMS). Solid-state galvanic cell technique based on calcium fluoride electrolyte was used to determine the standard molar Gibbs energies of formations of these aluminates. The standard molar Gibbs energies of formation of these three aluminates calculated from KEQMS and galvanic cell measurements were in good agreement. Heat capacities of individual ternary oxides were measured from 127 to 868 K using differential scanning calorimetry. Thermodynamic tables representing the values of Δ fH0(298.15 K), S0(298.15 K) S0( T), Cp0( T), H0( T), { H0( T)- H0(298.15 K)}, G0( T), Δ fH0( T), Δ fG 0( T) and free energy function (fef) were constructed using second law analysis and FACTSAGE thermo-chemical database software.

  1. Crystallization kinetics of Fe-B based amorphous alloys studied in-situ using X-rays diffraction and differential scanning calorimetry

    Directory of Open Access Journals (Sweden)

    Santos D.R. dos

    2001-01-01

    Full Text Available The crystallization processes for the amorphous metallic alloys Fe74B17Si2Ni4Mo3 and Fe86B6Zr7Cu1 (at. % were investigated using X-rays diffraction measurements performed in-situ during Joule-heating, with simultaneous monitoring of the electrical resistance. We determined the main structural transitions and crystalline phases formed during heating, and correlated these results to the observed resistance variations. As the annealing current is increased, the resistance shows an initial decrease due to stress relaxation, followed by a drop to a minimum value due to massive nucleation and growth of alpha-Fe nanocrystals. Further annealing causes the formation of small fractions of Fe-B, B2Zr or ZrO2, while the resistance increases due to temperature enhancement. In situ XRD measurements allowed the identification of metastable phases, as the gamma-Fe phase which occurs at high temperatures. The exothermal peaks observed in the differential scanning calorimetry (DSC for each alloy corroborate the results. We also have performed DSC measurements with several heating rates, which allowed the determination of the Avrami exponent and crystallization activation energy for each alloy. The obtained activation energies (362 and 301 kJ/mol for Fe-B-Zr-Cu; 323 kJ/mol for Fe-B-Si-Ni-Mo are comparable to reported values for amorphous iron alloys, while the Avrami exponent values (n = 1.0 or n = 1.2 are consistent with diffusion controlled crystallization processes with nucleation rates close to zero.

  2. Non-isothermal crystallization kinetics and fragility of (Cu46Zr47Al7)97Ti3 bulk metallic glass investigated by differential scanning calorimetry

    International Nuclear Information System (INIS)

    Zhu, Man; Li, Junjie; Yao, Lijuan; Jian, Zengyun; Chang, Fang’e; Yang, Gencang

    2013-01-01

    Highlights: • Non-isothermal crystallization kinetics of (Cu 46 Zr 47 Al 7 ) 97 Ti 3 BMGs was studied. • Two-stage of crystallization process is confirmed by DSC. • The nucleation process is difficult than growth process during crystallization. • The second crystallization process is the most sensitive to heating rate. • Kinetic fragility index is evaluated suggesting it is an intermediate glass. - Abstract: In this paper, bulk metallic glasses with the composition of (Cu 46 Zr 47 Al 7 ) 97 Ti 3 were prepared by copper mold casting technique. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to investigate its structure and non-isothermal crystallization kinetics. DSC traces revealed that it undergoes two-stage crystallization. The activation energies corresponding to the characteristic temperatures have been calculated, and the results reveal that the as-cast alloys have a good thermal stability in thermodynamics. Based on Kissinger equation, the activation energies for glass transition, the first and second crystallization processes were obtained as 485 ± 16 kJ/mol, 331 ± 7 kJ/mol and 210 ± 3 kJ/mol, respectively, suggesting that the nucleation process is more difficult than the grain growth process. The fitting curves using Lasocka's empirical relation show that the influence of the heating rate for crystallization is larger than glass transition. Furthermore, the kinetic fragility for (Cu 46 Zr 47 Al 7 ) 97 Ti 3 bulk metallic glasses is evaluated. Depending on the fragility index, (Cu 46 Zr 47 Al 7 ) 97 Ti 3 bulk metallic glasses should be considered as “intermediate glasses”

  3. Rapid diagnosis and differentiation of microbial pathogens in otitis media with a combined Raman spectroscopy and low-coherence interferometry probe: toward in vivo implementation

    Science.gov (United States)

    Zhao, Youbo; Monroy, Guillermo L.; You, Sixian; Shelton, Ryan L.; Nolan, Ryan M.; Tu, Haohua; Chaney, Eric J.; Boppart, Stephen A.

    2016-10-01

    We investigate and demonstrate the feasibility of using a combined Raman scattering (RS) spectroscopy and low-coherence interferometry (LCI) probe to differentiate microbial pathogens and improve our diagnostic ability of ear infections [otitis media (OM)]. While the RS probe provides noninvasive molecular information to identify and differentiate infectious microorganisms, the LCI probe helps to identify depth-resolved structural information as well as to guide and monitor positioning of the Raman spectroscopy beam for relatively longer signal acquisition times. A series of phantom studies, including the use of human middle ear effusion samples, were performed to mimic the conditions of in vivo investigations. These were also conducted to validate the feasibility of using this combined RS/LCI probe for point-of-care diagnosis of the infectious pathogen(s) in OM patients. This work establishes important parameters for future in vivo investigations of fast and accurate determination and diagnosis of infectious microorganisms in OM patients, potentially improving the efficacy and outcome of OM treatments, and importantly reducing the misuse of antibiotics in the presence of viral infections.

  4. [Differentiation of Amanita hemibapha (Berk. & Broome) Sacc. subsp. hemibapha and Amanita hemibapha var. ochracea Zhu L. Yang by Fourier transform infrared spectroscopy].

    Science.gov (United States)

    Shi, You-Ming; Liu, Gang; Zhou, Xiang-Ping; Zhou, Ji-Guo; Liu, Jian-Hong; Song, Ding-Shan

    2009-02-01

    In order to demonstrate the ability of Fourier transform infrared (FTIR) spectroscopy for the differentiation of macro-fungi at variety level, FTIR spectroscopy was used to obtain vibrational spectra of Amanita hemibapha (Berk. & Broome) Sacc. subsp. hemibapha and Amanita hemibapha var. ochracea Zhu L. Yang. The results show that their spectra are very similar to each other, with a small difference in the relative intensity of absorbance. For the purpose of enhancing the spectral resolution and amplifying the differences, the first-derivative spectra and second-derivative spectra were selected for evaluating the correlation coefficients respectively. The results show that the second-derivative spectra of two fruit bodies of Amanita hemibapha (Berk. & Broome) Sacc. subsp. hemibapha and one fruit body of Amanita hemibapha var. ochracea Zhu L. Yang have obvious differences, the correlation coefficients are only 0.245 and 0.356 respectively, the second-derivative spectra of two fruit bodies of Amanita hemibapha (Berk. &Broome) Sacc. subsp. hemibapha are very similar, and the correlation coefficient is 0.865. The authors' results show that Fourier transform infrared spectroscopy in combination with correlation analysis method can be used to identify Amanita hemibapha (Berk. & Broome) Sacc. subsp. hemibapha and Amanita hemibapha var. ochracea Zhu L. Yang rapidly and accurately.

  5. On-line determination of nanometric and sub-micrometric particle physicochemical characteristics using spectral imaging-aided Laser-Induced Breakdown Spectroscopy coupled with a Scanning Mobility Particle Sizer

    Science.gov (United States)

    Amodeo, Tanguy; Dutouquet, Christophe; Le Bihan, Olivier; Attoui, Michel; Frejafon, Emeric

    2009-10-01

    Laser-Induced Breakdown Spectroscopy has been employed to detect sodium chloride and metallic particles with sizes ranging from 40 nm up to 1 µm produced by two different particle generators. The Laser-Induced Breakdown Spectroscopy technique combined with a Scanning Mobility Particle Sizer was evaluated as a potential candidate for workplace surveillance in industries producing nanoparticle-based materials. Though research is still currently under way to secure nanoparticle production processes, the risk of accidental release is not to be neglected. Consequently, there is an urgent need for the manufacturers to have at their command a tool enabling leak detection in-situ and in real time so as to protect workers from potential exposure. In this context, experiments dedicated to laser-induced plasma particle interaction were performed. To begin with, spectral images of the laser-induced plasma vaporizing particles were recorded to visualize the spatio-temporal evolution of the atomized matter and to infer the best recording parameters for Laser-Induced Breakdown Spectroscopy analytical purposes, taking into account our experimental set-up specificity. Then, on this basis, time-resolved spectroscopic measurements were performed to make a first assumption of the Laser-Induced Breakdown Spectroscopy potentialities. Particle size dependency on the LIBS signal was examined. Repeatability and limits of detection were assessed and discussed. All the experiments carried out with low particle concentrations point out the high time delays corresponding to the Laser-Induced Breakdown Spectroscopy signal emergence. Plasma temperature temporal evolution was found to be a key parameter to explain this peculiarity inherent to laser/plasma/particle interaction.

  6. Negative differential resistance of TEMPO molecules on Si(111)

    NARCIS (Netherlands)

    Hallbäck, A.S.V.M.; Poelsema, Bene; Zandvliet, Henricus J.W.

    2007-01-01

    Negative differential resistance (NDR) has been observed for individual 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) molecules on Si(1 1 1) in ultra high vacuum (UHV) scanning tunneling microscopy (STM) and spectroscopy (STS) measurements at room temperature. NDR effects were observed exclusively at

  7. Functional biocompatible magnetite-cellulose nanocomposite fibrous networks: Characterization by fourier transformed infrared spectroscopy, X-ray powder diffraction and field emission scanning electron microscopy analysis

    Science.gov (United States)

    Habibi, Neda

    2015-02-01

    The preparation and characterization of functional biocompatible magnetite-cellulose nano-composite fibrous material is described. Magnetite-cellulose nano-composite was prepared by a combination of the solution-based formation of magnetic nano-particles and subsequent coating with amino celluloses. Characterization was accomplished using X-ray powder diffraction (XRD), fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. The peaks of Fe3O4 in the XRD pattern of nanocomposite confirm existence of the nanoparticles in the amino cellulose matrix. Magnetite-cellulose particles exhibit an average diameter of roughly 33 nm as demonstrated by field emission scanning electron microscopy. Magnetite nanoparticles were irregular spheres dispersed in the cellulose matrix. The vibration corresponding to the Nsbnd CH3 functional group about 2850 cm-1 is assigned in the FTIR spectra. Functionalized magnetite-cellulose nano-composite polymers have a potential range of application as targeted drug delivery system in biomedical field.

  8. Comparison of Blue Wavelengths and Scan Velocity Effects on the Detection of Enamel Surface Caries Using Steady-State Laser-Induced Autofluorescence Spectroscopy

    Science.gov (United States)

    Khosroshahi, M. E.; Khoi, N. Taghizadeh

    2014-05-01

    The results of sound and carious enamel fl uorescence emission study using (i) different blue wavelengths, (ii) different scan velocity, and (iii) spectral ratio are reported. The samples were irradiated using a tunable argon laser emitting at 459 and 488 nm and a 405 nm laser at two different scan velocities of 0.23 and 0.5 mm/s. The results showed a spectral band of 443-492 nm for 405 nm, 493-522 nm for 459 nm, and 526-625 nm for 488 nm lasers for sound teeth. It was found from the emission spectra that with increase in the excitation wavelength, the corresponding primary peaks of the carious samples showed Stokes shifts of 4, 6, and 2 nm, respectively. No signifi cant change was observed for the secondary peaks. Also, in all cases, the intensity of fl uorescence signals of sound teeth was higher than those of carious teeth. The highest shape factor of 1.82 and integrated intensity ratio of 1.20 were achieved at 405 nm, which provides relatively better tissue discrimination. Also, increasing the scan velocity reduced the signal amplitudes in both sound and carious samples.

  9. Investigation of Laser Induced Breakdown Spectroscopy (LIBS) for the Differentiation of Nerve and Gland Tissue—A Possible Application for a Laser Surgery Feedback Control Mechanism

    Science.gov (United States)

    Mehari, F.; Rohde, M.; Knipfer, C.; Kanawade, R.; Klämpfl, F.; W., Adler; Oetter, N.; Stelzle, F.; Schmidt, M.

    2016-06-01

    Laser surgery provides clean, fast and accurate modeling of tissue. However, the inability to determine what kind of tissue is being ablated at the bottom of the cut may lead to the iatrogenic damage of structures that were meant to be preserved. In this context, nerve preservation is one of the key challenges in any surgical procedure. One example is the treatment of parotid gland pathologies, where the facial nerve (N. VII) and its main branches run through and fan out inside the glands parenchyma. A feedback system that automatically stops the ablation to prevent nerve-tissue damage could greatly increase the applicability and safety of surgical laser systems. In the present study, Laser Induced Breakdown Spectroscopy (LIBS) is used to differentiate between nerve and gland tissue of an ex-vivo pig animal model. The LIBS results obtained in this preliminary experiment suggest that the measured spectra, containing atomic and molecular emissions, can be used to differentiate between the two tissue types. The measurements and differentiation were performed in open air and under normal stray light conditions.

  10. Pilot study of laser induced breakdown spectroscopy for tissue differentiation by monitoring the plume created during laser surgery — An approach on a feedback Laser control mechanism

    Science.gov (United States)

    Kanawade, Rajesh; Mehari, Fanuel; Knipfer, Christian; Rohde, Maximilian; Tangermann-Gerk, Katja; Schmidt, Michael; Stelzle, Florian

    2013-09-01

    This study focuses on tissue differentiation using 'Laser Induced Breakdown Spectroscopy' (LIBS) by monitoring the plasma plume created during laser surgery processes. This technique is aimed at controlling a laser surgery feedback system in real time. An Excimer laser (Ar-F 193 nm) was used for the ablation of tissue samples. Fat, muscle, nerve and skin tissue samples of bisected ex-vivo pig heads were prepared as test objects for the ablation procedure. A single fiber was used to collect emissions and deliver them to a spectrometer. The obtained LIBS spectra in the measured emissions were analyzed to determine each tissue type according to their chemical composition. The elements found in the samples and their emission spectra were in agreement with those described in literature. The collected LIBS spectra were analyzed to differentiate the tissues using statistical data analysis: Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) and Receiver Operating Characteristics (ROC). The obtained preliminary results suggest a successful differentiation of the target tissues with high sensitivity and specificity. The main goal of this study was to qualitatively identify tissue types during laser ablation, which will provide a real time feedback mechanism for clinical Laser surgery applications to significantly improve the accuracy and safety of laser surgery procedures.

  11. Role of magnetic resonance spectroscopy for the differentiation of recurrent glioma from radiation necrosis: A systematic review and meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hui [Department of Neurosurgery, Air Force General Hospital of the Chinese PLA, 30 Fucheng Road, Haidian District, Beijing 100142 (China); Department of Neurosurgery, Chinese PLA General Hospital, 28 Fuxing Road,Haidian District, Beijing 100853 (China); Ma, Li [Department of Anesthesiology, Beijing Military General Hospital, Beijing 100700 (China); Wang, Qun; Zheng, Xuan; Wu, Chen [Department of Neurosurgery, Chinese PLA General Hospital, 28 Fuxing Road,Haidian District, Beijing 100853 (China); Xu, Bai-nan, E-mail: bn_xu@yahoo.com [Department of Neurosurgery, Chinese PLA General Hospital, 28 Fuxing Road,Haidian District, Beijing 100853 (China)

    2014-12-15

    Purpose: Differentiating glioma recurrence from radiation necrosis remains a great challenge. We conducted a meta-analysis to evaluate the diagnostic quality of magnetic resonance spectroscopy (MRS) in differentiating glioma recurrence from radiation necrosis. Methods: Studies about evaluation of MRS for the differential diagnosis of glioma recurrence from radiation necrosis were systematically searched in PubMed, Embase and Chinese Biomedical databases up to May 4, 2014. The data were extracted to perform heterogeneity test, threshold effect test and to calculate sensitivity (SEN), specificity (SPE) and areas under summary receiver operating characteristic curve (SROC). Results: Eighteen articles comprising a total sample size of 455 patients (447 lesions) with suspected glioma recurrence after radiotherapy, met all inclusion and exclusion criteria, and were included in our meta-analysis. Quantitative synthesis of studies showed that the pooled SEN and SPE for Cho/Cr ratio were 0.83 (95% CI: 0.77, 0.89) and 0.83 (95% CI: 0.74, 0.90). The area under the curve (AUC) under the SROC was 0.9001. The pooled SEN and SPE for Cho/NAA ratio were 0.88 (95% CI: 0.81, 0.93) and 0.86 (95% CI: 0.76, 0.93). The AUC under the SROC was 0.9185. Conclusion: This meta-analysis shows that MRS alone has moderate diagnostic performance in differentiating glioma recurrence from radiation necrosis using metabolite ratios like Cho/Cr and Cho/NAA ratio. It is strongly recommended that MRS should combine other advanced imaging technologies to improve diagnostic accuracy. This article underlines the importance of implementing multimodal imaging trials and multicentre trials in the future.

  12. A catheter-based near-infrared scanning spectroscopy system for imaging lipid-rich plaques in human coronary arteries in vivo

    Science.gov (United States)

    Gardner, Craig M.; Lisauskas, Jennifer; Hull, Edward L.; Tan, Huwei; Sum, Stephen; Meese, Thomas; Jiang, Chunsheng; Madden, Sean; Caplan, Jay; Muller, James E.

    2007-09-01

    Although heart disease remains the leading cause of death in the industrialized world, there is still no method, even under cardiac catheterization, to reliably identify those atherosclerotic lesions most likely to lead to heart attack and death. These lesions, which are often non-stenotic, are frequently comprised of a necrotic, lipid-rich core overlaid with a thin fibrous cap infiltrated with inflammatory cells. InfraReDx has developed a scanning, near-infrared, optical-fiber-based, spectroscopic cardiac catheter system capable of acquiring NIR reflectance spectra from coronary arteries through flowing blood under automated pullback and rotation in order to identify lipid-rich plaques (LRP). The scanning laser source and associated detection electronics produce a spectrum in 5 ms at a collection rate of 40 Hz, yielding thousands of spectra in a single pullback. The system console analyzes the spectral data with a chemometric model, producing a hyperspectral image (a Chemogram, see figure below) that identifies LRP encountered in the region interrogated by the system. We describe the system architecture and components, explain the experimental procedure by which the chemometric model was constructed from spectral data and histology-based reference information collected from autopsy hearts, and provide representative data from ongoing ex vivo and clinical studies.

  13. Functional biocompatible magnetite-cellulose nanocomposite fibrous networks: Characterization by fourier transformed infrared spectroscopy, X-ray powder diffraction and field emission scanning electron microscopy analysis.

    Science.gov (United States)

    Habibi, Neda

    2015-02-05

    The preparation and characterization of functional biocompatible magnetite-cellulose nano-composite fibrous material is described. Magnetite-cellulose nano-composite was prepared by a combination of the solution-based formation of magnetic nano-particles and subsequent coating with amino celluloses. Characterization was accomplished using X-ray powder diffraction (XRD), fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. The peaks of Fe3O4 in the XRD pattern of nanocomposite confirm existence of the nanoparticles in the amino cellulose matrix. Magnetite-cellulose particles exhibit an average diameter of roughly 33nm as demonstrated by field emission scanning electron microscopy. Magnetite nanoparticles were irregular spheres dispersed in the cellulose matrix. The vibration corresponding to the NCH3 functional group about 2850cm(-1) is assigned in the FTIR spectra. Functionalized magnetite-cellulose nano-composite polymers have a potential range of application as targeted drug delivery system in biomedical field. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Time-resolved spectral characterization of ring cavity surface emitting and ridge-type distributed feedback quantum cascade lasers by step-scan FT-IR spectroscopy.

    Science.gov (United States)

    Brandstetter, Markus; Genner, Andreas; Schwarzer, Clemens; Mujagic, Elvis; Strasser, Gottfried; Lendl, Bernhard

    2014-02-10

    We present the time-resolved comparison of pulsed 2nd order ring cavity surface emitting (RCSE) quantum cascade lasers (QCLs) and pulsed 1st order ridge-type distributed feedback (DFB) QCLs using a step-scan Fourier transform infrared (FT-IR) spectrometer. Laser devices were part of QCL arrays and fabricated from the same laser material. Required grating periods were adjusted to account for the grating order. The step-scan technique provided a spectral resolution of 0.1 cm(-1) and a time resolution of 2 ns. As a result, it was possible to gain information about the tuning behavior and potential mode-hops of the investigated lasers. Different cavity-lengths were compared, including 0.9 mm and 3.2 mm long ridge-type and 0.97 mm (circumference) ring-type cavities. RCSE QCLs were found to have improved emission properties in terms of line-stability, tuning rate and maximum emission time compared to ridge-type lasers.

  15. Qualitative tissue differentiation by analysing the intensity ratios of atomic emission lines using laser induced breakdown spectroscopy (LIBS): prospects for a feedback mechanism for surgical laser systems.

    Science.gov (United States)

    Kanawade, Rajesh; Mahari, Fanuel; Klämpfl, Florian; Rohde, Maximilian; Knipfer, Christian; Tangermann-Gerk, Katja; Adler, Werner; Schmidt, Michael; Stelzle, Florian

    2015-01-01

    The research work presented in this paper focuses on qualitative tissue differentiation by monitoring the intensity ratios of atomic emissions using 'Laser Induced Breakdown Spectroscopy' (LIBS) on the plasma plume created during laser tissue ablation. The background of this study is to establish a real time feedback control mechanism for clinical laser surgery systems during the laser ablation process. Ex-vivo domestic pig tissue samples (muscle, fat, nerve and skin) were used in this experiment. Atomic emission intensity ratios were analyzed to find a characteristic spectral line for each tissue. The results showed characteristic elemental emission intensity ratios for the respective tissues. The spectral lines and intensity ratios of these specific elements varied among the different tissue types. The main goal of this study is to qualitatively and precisely identify different tissue types for tissue specific laser surgery. © 2015 The Authors. Journal of Biophotonics published by WILEY-VCH Verlag.

  16. Evaluation and differentiation of the Betulaceae birch bark species and their bioactive triterpene content using analytical FT-vibrational spectroscopy and GC-MS.

    Science.gov (United States)

    Cîntă-Pînzaru, Simona; Dehelean, Cristina A; Soica, Codruta; Culea, Monica; Borcan, Florin

    2012-07-18

    Aiming to obtain the highest triterpene content in the extraction products, nine bark samples from the forest abundant flora of Apuseni Mountains, Romania were Raman spectroscopically evaluated. Three different natural extracts from Betula pendula Roth birch bark have been obtained and characterized using Fourier transform vibrational spectra. This study shows that principal components of the birch tree extract can be rapidly recognized and differentiated based on their vibrational fingerprint band shape and intensity. The vibrational spectroscopy results are supported by the GC-MS data. Based on IR and Raman analysis, one can conclude that all the extracts, independent on the solvent(s) used, revealed dominant betulin species, followed by lupeol. Since Raman measurements could also be performed on fresh plant material, we demonstrated the possibility to apply the present results for the prediction of the highest triterpene content in bark species, for the selection of harvesting time or individual genotypes directly in the field, with appropriate portable Raman equipment.

  17. Characterization of sintered samples of La/Sr/Cu/O by X-ray diffraction, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS)

    International Nuclear Information System (INIS)

    Gonzalez, C.O. de; Polla, Griselda; Manghi, Estela

    1987-01-01

    Samples of La/Sr/Cu/O were sinterized by solid state reaction starting from a nominal composition of La 1 .8, Sr 0 .2, CuO 4 . They presented superconductive properties with T c = 40.9 K (onset) and δ T c = 17 K. Two phases were observed by X-ray diffraction and the more abundant was the tetragonal phase. The mean grain size was 1-5 μm. The X-ray photoelectron spectroscopy measurements were carried out using Mg kα (1486.6 eV) as incident radiation. Sample temperature was varied between -180 deg C and 420 deg C, approximately. The temperature variation produces a change in the atomic concentration of the surface components. Deconvolutions of the O 1s peaks show three components with binding energies (B.E.). The decomposition of Cu 2p 3 /2 peaks presents two components corresponding to Cu + and Cu 2+ . (Author) [es

  18. Exploring Geographical Differentiation of the Hoelen Medicinal Mushroom, Wolfiporia extensa (Agaricomycetes), Using Fourier-Transform Infrared Spectroscopy Combined with Multivariate Analysis.

    Science.gov (United States)

    Li, Yan; Zhang, Ji; Zhao, Yanli; Liu, Honggao; Wang, Yuanzhong; Jin, Hang

    2016-01-01

    In this study the geographical differentiation of dried sclerotia of the medicinal mushroom Wolfiporia extensa, obtained from different regions in Yunnan Province, China, was explored using Fourier-transform infrared (FT-IR) spectroscopy coupled with multivariate data analysis. The FT-IR spectra of 97 samples were obtained for wave numbers ranging from 4000 to 400 cm-1. Then, the fingerprint region of 1800-600 cm-1 of the FT-IR spectrum, rather than the full spectrum, was analyzed. Different pretreatments were applied on the spectra, and a discriminant analysis model based on the Mahalanobis distance was developed to select an optimal pretreatment combination. Two unsupervised pattern recognition procedures- principal component analysis and hierarchical cluster analysis-were applied to enhance the authenticity of discrimination of the specimens. The results showed that excellent classification could be obtained after optimizing spectral pretreatment. The tested samples were successfully discriminated according to their geographical locations. The chemical properties of dried sclerotia of W. extensa were clearly dependent on the mushroom's geographical origins. Furthermore, an interesting finding implied that the elevations of collection areas may have effects on the chemical components of wild W. extensa sclerotia. Overall, this study highlights the feasibility of FT-IR spectroscopy combined with multivariate data analysis in particular for exploring the distinction of different regional W. extensa sclerotia samples. This research could also serve as a basis for the exploitation and utilization of medicinal mushrooms.

  19. Evaluation of Efficacy of Bone Scan With SPECT/CT in the Management of Low Back Pain: A Study Supported by Differential Diagnostic Local Anesthetic Blocks.

    Science.gov (United States)

    Jain, Anuj; Jain, Suruchi; Agarwal, Anil; Gambhir, Sanjay; Shamshery, Chetna; Agarwal, Amita

    2015-12-01

    Conventional radiologic modalities provide details only about the anatomic aspect of the various structures of the spine. Frequently the structures that show abnormal morphology may not be the cause of low back pain (LBP). Functional imaging in the form of bone scan along with single photon emission computerized tomography (SPECT/CT) may be helpful in identifying structures causing pain, whether morphologically normal or not. The objective of this study is to evaluate the role of bone scan with SPECT/CT in management of patients with LBP. This is randomized double-blinded controlled study performed on 80 patients with LBP aged 20 to 80 years, ASA physical status I to III. Patients were randomized into bone scan and control groups consisting of 40 patients each. On the basis of the clinical features and radiologic findings a clinical diagnosis was made. After making a clinical diagnosis, the patients in bone scan group were subjected to bone scan with SPECT/CT. On the basis of the finding of the bone scan and SPECT/CT, a new working diagnosis was made and intervention was performed according to the new working diagnosis. Diagnostic blocks in the control group were given based on clinical diagnosis. Controlled comparative diagnostic blocks were performed with local anesthetic. The pain score just after the diagnostic block and at the time of discharge (approximately 4 h later) was recorded; the pain relief was recorded in percentage. In both the groups, sacroilitis was the most common diagnosis followed by facet joint arthropathy. The number of patients obtaining pain relief of >50% was significantly higher in the bone scan-positive group as compared with the control group. Three new clinical conditions were identified in the bone scan group. These conditions were multiple myeloma, avascular necrosis of the femoral head, and ankylosing spondylitis. Bone scan with SPECT/CT was found to complement the clinical workup of patients with LBP. Inclusion of bone scan with

  20. Study of single voxel {sup 1}H MR spectroscopy of bone tumors: Differentiation of benign from malignant tumors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jing; Cheng, Kebin [Department of Radiology, Beijing Jishuitan Hospital, Beijing (China); Ding, Yi [Department of Orthopaedic Oncology, Beijing Jishuitan Hospital, Beijing (China); Liang, Wei [Department of Radiology, Beijing Jishuitan Hospital, Beijing (China); Ding, Yi [Department of Pathology, Beijing Jishuitan Hospital, Beijing (China); Vanel, Daniel [Rizzoli Institute, Bologna (Italy); Cheng, Xiaoguang, E-mail: xiao65@263.net [Department of Radiology, Beijing Jishuitan Hospital, Beijing (China)

    2013-12-01

    Objective: To evaluate the clinical application of single voxel {sup 1}H MRS in the discrimination of benign and malignant bone tumors. Materials and methods: Eighty-three patients (64 male, 19 female), presenting with a bone tumor, were examined on a 1.5 T MRI scanner. Using pathological results as a gold standard, there were 34 benign and 49 malignant tumors. After plain MRI scans, a 3D fast SPGR sequence was used for dynamic contrast-enhanced scanning. Dynamic images were transferred to the workstation, where the region of maximal enhancement was identified for prescription of the {sup 1}H MRS sequence. Single-voxel {sup 1}H MRS was then performed with the probe-p sequence, TR/TE = 1500/110 ms, VOI ranging from 14.4 mm × 7.3 mm × 20.2 mm to 27.9 mm × 25.5 mm × 20.1 mm, automatic shimming and water suppression, 15 min post-contrast. For control purposes, the 3rd lumbar spine vertebral body of six patients having lumbar disc herniation (LDH) without systemic disease was examined with {sup 1}H MRS of normal bone marrow. The static contrast enhancement scan was used for these LDH patients. Conversion of raw MR signal to an MR spectrum was performed using SAGE 7. Cho/Lip (choline/lipids) peak height ratios were calculated. ROC curve analysis was used to determine the cut-off of Cho/Lip ratio for discrimination. Results: For malignant tumors, one resonance at 3.30–3.19 ppm attributed to choline and another at 1.14–1.55 ppm attributed to lipid were detected. With normal bone marrow and most benign tumors, no choline signal was detected. Choline was only found in six benign lesions. With a threshold for Cho/Lip peak height ratio of 0.2, the area under ROC curve was 0.819. The corresponding sensitivity and specificity of {sup 1}H MRS were 76% and 88%. Conclusions: Single voxel {sup 1}H MRS can help in discriminating benign and malignant bone tumors.

  1. Electronic characterization of LaAlO{sub 3}-SrTiO{sub 3} interfaces by scanning tunneling spectroscopy; Elektronische Charakterisierung von LaAlO{sub 3}-SrTiO{sub 3}-Grenzflaechen mittels Rastertunnelspektroskopie

    Energy Technology Data Exchange (ETDEWEB)

    Breitschaft, Martin

    2010-10-22

    When LaAlO{sub 3} is epitaxially grown on TiO{sub 2}-terminated SrTiO{sub 3}, an electrically conducting interface is generated. In this respect, the physical properties of the interface differ substantially from those of both LaAlO{sub 3} and SrTiO{sub 3}, which are electrically insulating in bulk form. This dissertation looks into the question of the microscopic structure of the conducting two-dimensional interface electron system. Comparing the electronic density of states of LaAlO{sub 3}-SrTiO{sub 3} interfaces measured by scanning tunneling spectroscopy with results of density functional theory, the interface electron system is found to be substantially coined by the hosting transition metal lattices. The comparison yields a detailed picture of the microscopic structure of the interface electron system. (orig.)

  2. Measuring diffusion of lipid-like probes in artificial and natural membranes by raster image correlation spectroscopy (RICS): use of a commercial laser-scanning microscope with analog detection.

    Science.gov (United States)

    Gielen, Ellen; Smisdom, Nick; vandeVen, Martin; De Clercq, Ben; Gratton, Enrico; Digman, Michelle; Rigo, Jean-Michel; Hofkens, Johan; Engelborghs, Yves; Ameloot, Marcel

    2009-05-05

    The heterogeneity in composition and interaction within the cellular membrane translates into a wide range of diffusion coefficients of its constituents. Therefore, several complementary microfluorimetric techniques such as fluorescence correlation spectroscopy (FCS), fluorescence recovery after photobleaching (FRAP) and single-particle tracking (SPT) have to be applied to explore the dynamics of membrane components. The recently introduced raster image correlation spectroscopy (RICS) offers a much wider dynamic range than each of these methods separately and allows for spatial mapping of the dynamic properties. RICS is implemented on a confocal laser-scanning microscope (CLSM), and the wide dynamic range is achieved by exploiting the inherent time information carried by the scanning laser beam in the generation of the confocal images. The original introduction of RICS used two-photon excitation and photon counting detection. However, most CLSM systems are based on one-photon excitation with analog detection. Here we report on the performance of such a commercial CLSM (Zeiss LSM 510 META) in the study of the diffusion of the fluorescent lipid analog 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indodicarbocyanine perchlorate (DiI-C(18)(5)) both in giant unilamellar vesicles and in the plasma membrane of living oligodendrocytes, i.e., the myelin-producing cells of the central nervous system. It is shown that RICS on a commercial CLSM with analog detection allows for reliable results in the study of membrane diffusion by removal of unwanted correlations introduced by the analog detection system. The results obtained compare well with those collected by FRAP and FCS.

  3. [Positron emission tomography-computed tomography with (18)F-fluorodeoxyglucose in patients with recurrent differentiated thyroid carcinoma and negative radioiodine scan. Diagnostic performance and relation with tyroglobulin levels].

    Science.gov (United States)

    Mariscal Labrador, E; García Burillo, A; Castell-Conesa, J; Obiols Alfonso, G; Kisiel González, N; Barios Profitós, M; Aguadé-Bruix, S; Mesa Manteca, J

    2013-01-01

    To assess the diagnostic performance of (18)F-FDG PET-CT scan and its relation to serum thyroglobulin (Tg) levels in patients with differentiated thyroid carcinoma with suspicion of persistence or recurrence of the disease and negative radioiodine scans. This is a retrospective analysis of 35 PET-CT studies in 25 patients (17 women, average age 48.8±15.2 years). The results were confirmed by histology or by ultrasonography and clinical follow-up. We analyzed the relationship between the diagnostic performance of the PET-CT scans and three levels of Tg: ≤2ng/ml; between 2 and 10 ng/ml, and >10ng/ml. We obtained 26 true-positives (TP), one false-positive (FP), 3 true-negatives (TN) and 5 false-negatives (FN). Of the 18 patients with PET-CTs classified as TP, 3 showed lesions at the post-thyroidectomy bed, 15 showed lymph node metastases and 5 were distant metastases. Sensitivity was 83.9% (95%CI: 69.3%-98.4%) and specificity was 75% (95%CI: 20%-100%). Regarding the three intervals of Tg, PET-CT scan showed TP rates of 37.5%, 83% and 100% in patients with Tg levels 10ng/ml, respectively. (18)F-FDG PET-CT demonstrates high diagnostic yield in local disease and distant lesions for the population of patients with differentiated thyroid carcinoma and persistence of the disease with negative radioiodine scans at Tg levels above 2ng/ml. Copyright © 2011 Elsevier España, S.L. y SEMNIM. All rights reserved.

  4. Dual-wavelength photo-Hall effect spectroscopy of deep levels in high resistive CdZnTe with negative differential photoconductivity

    Science.gov (United States)

    Musiienko, A.; Grill, R.; Moravec, P.; Korcsmáros, G.; Rejhon, M.; Pekárek, J.; Elhadidy, H.; Šedivý, L.; Vasylchenko, I.

    2018-04-01

    Photo-Hall effect spectroscopy was used in the study of deep levels in high resistive CdZnTe. The monochromator excitation in the photon energy range 0.65-1.77 eV was complemented by a laser diode high-intensity excitation at selected photon energies. A single sample characterized by multiple unusual features like negative differential photoconductivity and anomalous depression of electron mobility was chosen for the detailed study involving measurements at both the steady and dynamic regimes. We revealed that the Hall mobility and photoconductivity can be both enhanced and suppressed by an additional illumination at certain photon energies. The anomalous mobility decrease was explained by an excitation of the inhomogeneously distributed deep level at the energy Ev + 1.0 eV, thus enhancing potential non-uniformities. The appearance of negative differential photoconductivity was interpreted by an intensified electron occupancy of that level by a direct valence band-to-level excitation. Modified Shockley-Read-Hall theory was used for fitting experimental results by a model comprising five deep levels. Properties of the deep levels and their impact on the device performance were deduced.

  5. Laser induced breakdown spectroscopy for bone and cartilage differentiation - ex vivo study as a prospect for a laser surgery feedback mechanism.

    Science.gov (United States)

    Mehari, Fanuel; Rohde, Maximilian; Knipfer, Christian; Kanawade, Rajesh; Klämpfl, Florian; Adler, Werner; Stelzle, Florian; Schmidt, Michael

    2014-11-01

    Laser surgery enables for very accurate, fast and clean modeling of tissue. The specific and controlled cutting and ablation of tissue, however, remains a central challenge in the field of clinical laser applications. The lack of information on what kind of tissue is being ablated at the bottom of the cut may lead to iatrogenic damage of structures that were meant to be preserved. One such example is the shaping or removal of diseased cartilaginous and bone tissue in the temporomandibular joint (TMJ). Diseases of the TMJ can induce deformation and perforation of the cartilaginous discus articularis, as well as alterations to the cartilaginous surface of the condyle or even the bone itself. This may result in restrictions of movement and pain. The aim of a surgical intervention ranges from specific ablation and shaping of diseased cartilage, bone or synovial tissues to extensive removal of TMJ structures. One approach to differentiate between these tissues is to use Laser Induced Breakdown Spectroscopy (LIBS). The ultimate goal is a LIBS guided feedback control system for surgical laser systems that enables real-time tissue identification for tissue specific ablation. In the presented study, the authors focused on the LIBS based differentiation between cartilage tissue and cortical bone tissue using an ex-vivo pig model.

  6. Correlated Raman micro-spectroscopy and scanning electron microscopy analyses of flame retardants in environmental samples: a micro-analytical tool for probing chemical composition, origin and spatial distribution.

    Science.gov (United States)

    Ghosal, Sutapa; Wagner, Jeff

    2013-07-07

    We present correlated application of two micro-analytical techniques: scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and Raman micro-spectroscopy (RMS) for the non-invasive characterization and molecular identification of flame retardants (FRs) in environmental dusts and consumer products. The SEM/EDS-RMS technique offers correlated, morphological, molecular, spatial distribution and semi-quantitative elemental concentration information at the individual particle level with micrometer spatial resolution and minimal sample preparation. The presented methodology uses SEM/EDS analyses for rapid detection of particles containing FR specific elements as potential indicators of FR presence in a sample followed by correlated RMS analyses of the same particles for characterization of the FR sub-regions and surrounding matrices. The spatially resolved characterization enabled by this approach provides insights into the distributional heterogeneity as well as potential transfer and exposure mechanisms for FRs in the environment that is typically not available through traditional FR analysis. We have used this methodology to reveal a heterogeneous distribution of highly concentrated deca-BDE particles in environmental dust, sometimes in association with identifiable consumer materials. The observed coexistence of deca-BDE with consumer material in dust is strongly indicative of its release into the environment via weathering/abrasion of consumer products. Ingestion of such enriched FR particles in dust represents a potential for instantaneous exposure to high FR concentrations. Therefore, correlated SEM/RMS analysis offers a novel investigative tool for addressing an area of important environmental concern.

  7. Surface-enhanced Raman spectroscopy of saliva proteins for the noninvasive differentiation of benign and malignant breast tumors.

    Science.gov (United States)

    Feng, Shangyuan; Huang, Shaohua; Lin, Duo; Chen, Guannan; Xu, Yuanji; Li, Yongzeng; Huang, Zufang; Pan, Jianji; Chen, Rong; Zeng, Haishan

    2015-01-01

    The capability of saliva protein analysis, based on membrane protein purification and surface-enhanced Raman spectroscopy (SERS), for detecting benign and malignant breast tumors is presented in this paper. A total of 97 SERS spectra from purified saliva proteins were acquired from samples obtained from three groups: 33 healthy subjects; 33 patients with benign breast tumors; and 31 patients with malignant breast tumors. Subtle but discernible changes in the mean SERS spectra of the three groups were observed. Tentative assignments of the saliva protein SERS spectra demonstrated that benign and malignant breast tumors led to several specific biomolecular changes of the saliva proteins. Multiclass partial least squares-discriminant analysis was utilized to analyze and classify the saliva protein SERS spectra from healthy subjects, benign breast tumor patients, and malignant breast tumor patients, yielding diagnostic sensitivities of 75.75%, 72.73%, and 74.19%, as well as specificities of 93.75%, 81.25%, and 86.36%, respectively. The results from this exploratory work demonstrate that saliva protein SERS analysis combined with partial least squares-discriminant analysis diagnostic algorithms has great potential for the noninvasive and label-free detection of breast cancer.

  8. Differentiation of frog fats from vegetable and marine oils by Fourier Transform Infrared Spectroscopy and chemometric analysis

    Directory of Open Access Journals (Sweden)

    A. N. Nina Naquiah

    2015-01-01

    Full Text Available The agro-based production and consumption of frogs coupled with world-wide trading have been increased in the recent years giving rise to the risk of frog fat adulteration in expensive vegetable and marine oils. For the first time, we profiled here frog fats using Fourier Transform Infrared (FTIR Spectroscopy coupled with multivariate principal component analysis (PCA. The comparison of the FTIR spectral absorbance intensities demonstrated linkage of frog fats to other edible fats and oils. Three commercially available marine oils and three vegetables oils were studied with frog fats and clear pattern of clusters with distinctive identifiable features were obtained through PCA modeling. PCA analysis identified 2922.21 cm-1, 2852.88 cm-1, 1745.45 cm-1, 1158.29 cm-1 and 721.51 cm-1 FTIR-frequencies as the most discriminating variables influencing the group separation into different clusters. This fundamental study has clear implications in the identification of frog fat from its marine and vegetable counterparts for the potential detection of frog fat adulteration in various fat and oils.

  9. Application of gamma-ray spectroscopy to the differentiation between mobile and deposited fission products in pipes

    International Nuclear Information System (INIS)

    Packer, T.W.; Armitage, B.H.

    1990-08-01

    A method has been developed to differentiate between material flowing in pipes and deposited on the pipe walls. This has been applied to a study of fission product release from irradiated fuel under severe accident conditions. A collimation arrangement has been examined which provides good discrimination between gamma- radiation arising from flowing gases/aerosols and from stationary deposits. A systematic examination has been made of gamma- radiation obtained from gases and deposits in pipes of different diameter for a number of collimator configurations. A system of calibration has been developed based on Monte-Carlo modelling which has been found to be in broad agreement with measured values. This knowledge has been applied to the data obtained in a real-time measurement undertaken on the FALCON reactor safety facility at AEA Technology, Winfrith

  10. Studies of x-ray localization and thickness dependence in atomic-scale elemental mapping by STEM energy-dispersive x-ray spectroscopy using single-frame scanning method.

    Science.gov (United States)

    Lu, Ping; Moya, Jaime M; Yuan, Renliang; Zuo, Jian Min

    2018-03-01

    The delocalization of x-ray signals limits the spatial resolution in atomic-scale elemental mapping by scanning transmission electron microscopy (STEM) using energy-dispersive x-ray spectroscopy (EDS). In this study, using a SrTiO 3 [001] single crystal, we show that the x-ray localization to atomic columns is strongly dependent on crystal thickness, and a thin crystal is critical for improving the spatial resolution in atomic-scale EDS mapping. A single-frame scanning technique is used in this study instead of the multiple-frame technique to avoid peak broadening due to tracking error. The strong thickness dependence is realized by measuring the full width at half maxima (FWHM) as well as the peak-to-valley (P/V) ratio of the EDS profiles for Ti K and Sr K + L, obtained at several crystal thicknesses. A FWHM of about 0.16 nm and a P/V ratio of greater than 7.0 are obtained for Ti K for a crystal thickness of less than 20 nm. With increasing crystal thickness, the FWHM and P/V ratio increases and decreases, respectively, indicating the advantage of using a thin crystal for high-resolution EDS mapping. Published by Elsevier B.V.

  11. Scanning tunneling spectroscopy studies of Bi2Sr2CaCu2O8+x from the strongly underdoped to strongly overdoped regime

    Science.gov (United States)

    Slezak, James

    2006-03-01

    Using atomically resolved scanning tunneling microscopy (STS), we investigate the electronic structure Bi2Sr2CaCu2O8+x across a range of doping levels from x ˜ 0.1 up to as high as ˜0.23, with significant changes in electronic structure observed above p˜0.21. New sample preparation processes [1] were used to produce heavily overdoped crystals suitable for the imaging of various forms of electronic heterogeneity. The evolution of the gap map δ(r), coherence peak height map A(r), the inelastic tunneling signatures φ(r), and the quasiparticle interference LDOS modulations, as well as their interrelations across this range of doping levels, will be presented. Additional authors: J. Lee, M. Wang, Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, U.S.A; K. Fujita, Department of Advanced Materials Science, University of Tokyo, Tokyo 113-0033, Japan; H. Eisaki, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Central 2, Umezono, Tsukuba, Ibaraki 305-8568; S. Uchida, Department of Physics, University of Tokyo, Tokyo 113-0033; and J. C. Davis, Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University. [1] J. Slezak, K. Fujita, J. C. Davis, in preparation (2005)

  12. Cooperative scans

    NARCIS (Netherlands)

    M. Zukowski (Marcin); P.A. Boncz (Peter); M.L. Kersten (Martin)

    2004-01-01

    textabstractData mining, information retrieval and other application areas exhibit a query load with multiple concurrent queries touching a large fraction of a relation. This leads to individual query plans based on a table scan or large index scan. The implementation of this access path in most

  13. [Ru(bpy)(3)](2+) as a reference in transient absorption spectroscopy: differential absorption coefficients for formation of the long-lived (3)MLCT excited state.

    Science.gov (United States)

    Müller, Pavel; Brettel, Klaus

    2012-04-01

    Transient absorption spectroscopy and other time-resolved methods are commonly used to study chemical reactions and biological processes induced by absorption of light. In order to scale the signal amplitude or to compare results obtained under different conditions, it is advisable to use a reference system, a standard of convenient and well-defined properties. Finding Tris(bipyridine)ruthenium(ii), [Ru(bpy)(3)](2+), a suitable candidate for a transient-absorption spectroscopy reference due to its favourable photochemical properties, we have determined accurate relative values of differential molar absorption coefficients (Δε) for light-induced formation of the metal-to-ligand charge transfer (MLCT) excited triplet state at several relevant wavelengths (wavelengths of commercially available lasers) in the UV and visible regions. We have also attempted to determine the absolute value of Δε close to the wavelength of maximum bleaching (∼450 nm) and we propose to narrow down the interval of conceivable values for Δε(450) from the broad range of published values (-0.88 × 10(4) M(-1)cm(-1) to -1.36 × 10(4) M(-1)cm(-1)) to -1.1 × 10(4) M(-1)cm(-1)± 15%. Having ourselves successfully applied [Ru(bpy)(3)](2+) as a standard in a recent time-resolved study of enzymatic DNA repair, we would like to encourage other scientists to use this convenient tool as a reference in their future spectroscopic studies on time scales from picoseconds to hundreds of nanoseconds.

  14. Correction of fluorescence for depth-specific optical and vascular properties using reflectance and differential path-length spectroscopy during PDT

    Science.gov (United States)

    van Zaane, F.; Middelburg, T. A.; de Bruijn, H. S.; van der Ploeg-van den Heuvel, A.; de Haas, E. R. M.; Sterenborg, H. J. C. M.; Neumann, H. A. M.; Robinson, D. J.

    2009-06-01

    Introduction: The rate of PpIX fluorescence photobleaching is routinely used as a dose metric for ALA-PDT. Diffuse reflection spectroscopy is often used to account for variations in tissue optical properties at the photosensitizer excitation and emission bands. It can be used to quantify changes in vascular parameters, such as blood volume fraction and saturation, and can aid understanding of tissue response to PDT. The volume and(/or) depth over which these signals are acquired are critical. The aim of this study is to use quantitative reflectance spectroscopy (DPS) to correct fluorescence for changes in tissue optical properties and monitor PDT. Materials & Methods: ALA was topically applied to hairless mice skin and the incubated spot was treated with PDT according to fractionated illumination schemes. DPS measurements of vascular parameters and optical properties were performed directly before and after illumination. Both the differential signal, delivery-and-collection-fiber signal and the collection fiber signal, which all probe different measurement volumes, are analyzed. Results & Conclusions: Analysis of DPS measurements shows that at the depth where most fluorescence originates, there is almost no blood present. During PDT vascular parameters at this depth stay constant. In more oxygenated layers of the tissue, the optical properties do change during PDT, suggesting that only a small part of PpIX fluorescence originates from the interesting depths where vascular response occurs. Correcting fluorescence emission spectra for optical changes at specific depths and not for the total of changes in a larger volume, as is usually done now, can improve PpIX photobleaching based treatment monitoring.

  15. Integration of Fluorescence Differential Path-Length Spectroscopy to Photodynamic Therapy of the Head and Neck Tumors is Useful in Monitoring Clinical Outcome

    Science.gov (United States)

    Karakullukcu, Baris; Kanick, Stephen; Aans, Jan Bonne; Sterenborg, Henricus; Tan, Bing; Amelink, Arjen; Robinson, Dominic

    2015-04-01

    The use of fluorescence differential pathlength spectroscopy (FDPS) has the potential to provide real-time information on photosensitiser pharmacokinetics, vascular physiology and photosensitizer photobleaching based dosimetry of tumors in the oral cavity receiving m-tetrahydroxyphenylchlorin (mTHPC) photodynamic therapy (PDT). Reflectance spectra can be used provide quantitative values of oxygen saturation, blood volume fraction, blood vessel diameter, and to determine the local optical properties that can be used to correct raw fluorescence for tissue absorption. Patients and methods: Twenty-seven lesions in the oral cavity, either dysplasias or cancer were interrogated using FDPS, before and immediately after the therapeutic illumination. The average tumor center to normal mucosa ratio of fluorescence was 1.50 ± 0.66. mTHPC photobleaching was observed in 24 of the lesions treated. The average extent of photobleaching was 81% ± 17%. Information from FDPS spectroscopy coupled with the clinical results of the treatment identified 3 types of correctable errors in the application of mTHPC-PDT: Two patients exhibited very low concentrations of photosensitizer in tumour center, indicating an ineffective i.v. injection of photosensitiser or an erroneous systemic distribution of mTHPC. In one in tumor we observed no photobleaching accompanied by a high blood volume fraction in the illuminated tissue, suggesting that the presence of blood prevented therapeutic light reaching the target tissue. All 3 of the these lesions had no clinical response to PDT. In four patients we observed less than 50% photobleaching at the tumor margins , suggesting a possible geographic miss. One patient in this group had a recurrence within 2 months after PDT even though the initial response was good. The integration of FDPS to clinical PDT yields data on tissue physiology, photosensitiser content and photobleaching that can help identify treatment errors that can potentially be corrected.

  16. Optimal differentiation of high- and low-grade glioma and metastasis: a meta-analysis of perfusion, diffusion, and spectroscopy metrics

    Energy Technology Data Exchange (ETDEWEB)

    Usinskiene, Jurgita; Venius, Jonas; Rynkeviciene, Ryte; Norkus, Darius; Suziedelis, Kestutis [National Cancer Institute, Radiology Center, Vilnius (Lithuania); Ulyte, Agne [Vilnius University, Faculty of Medicine, Vilnius (Lithuania); Bjoernerud, Atle [Oslo University Hospital, Department of Physics, Oslo (Norway); Oslo University Hospital, The Intervention Centre, Oslo (Norway); Katsaros, Vasileios K. [General Anti-Cancer and Oncological Hospital ' ' St. Savvas' ' , Athens (Greece); Letautiene, Simona; Aleknavicius, Eduardas [National Cancer Institute, Radiology Center, Vilnius (Lithuania); Vilnius University, Faculty of Medicine, Vilnius (Lithuania); Rocka, Saulius [Vilnius University, Faculty of Medicine, Vilnius (Lithuania); Faculty of Medicine Vilnius University, Neuroangiosurgery Center, Vilnius (Lithuania); Usinskas, Andrius [Vilnius Gedimino Technical University, Department of Electronic Systems, Vilnius (Lithuania)

    2016-04-15

    To perform a meta-analysis of advanced magnetic resonance imaging (MRI) metrics, including relative cerebral blood volume (rCBV), normalized apparent diffusion coefficient (nADC), and spectroscopy ratios choline/creatine (Cho/Cr) and choline/N-acetyl aspartate (Cho/NAA), for the differentiation of high- and low-grade gliomas (HGG, LGG) and metastases (MTS). For systematic review, 83 articles (dated 2000-2013) were selected from the NCBI database. Twenty-four, twenty-two, and eight articles were included respectively for spectroscopy, rCBV, and nADC meta-analysis. In the meta-analysis, we calculated overall means for rCBV, nADC, Cho/Cr (short TE - from 20 to 35 ms, medium - from 135 to 144 ms), and Cho/NAA for the HGG, LGG, and MTS groups. We used random effects model to obtain weighted averages and select thresholds. Overall means (with 95 % CI) for rCBV, nADC, Cho/Cr (short and medium echo time, TE), and Cho/NAA were: for HGG 5.47 (4.78-6.15), 1.38 (1.16-1.60), 2.40 (1.67-3.13), 3.27 (2.78-3.77), and 4.71 (3.24-6.19); for LGG 2.00 (1.71-2.28), 1.61 (1.36-1.87), 1.46 (1.20-1.72), 1.71 (1.49-1.93), and 2.36 (1.50-3.23); for MTS 5.06 (3.85-6.27), 1.35 (1.06-1.64), 1.89 (1.72-2.06), 3.14 (1.57-4.72), (Cho/NAA was not available). LGG had significantly lower rCBV, Cho/Cr, and Cho/NAA values than HGG or MTS. No significant differences were found for nADC. Best differentiation between HGG and LGG is obtained from rCBV, Cho/Cr, and Cho/NAA metrics. MTS could not be reliably distinguished from HGG by the methods investigated. (orig.)

  17. Heterodyned holographic spectroscopy

    NARCIS (Netherlands)

    Douglas, NG

    In holographic spectroscopy an image of an interference pattern is projected onto a detector and transformed back to the input spectrum. The general characteristics are similar to those of Fourier transform spectroscopy, but the spectrum is obtained without scanning. In the heterodyned arrangement

  18. Preliminary study for differential diagnosis of intracranial tumors using in vivo quantitative proton MR spectroscopy with correction for T2 relaxation time

    International Nuclear Information System (INIS)

    Isobe, Tomonori; Yamamoto, Tetsuya; Akutsu, Hiroyoshi; Shiigai, Masanari; Shibata, Yasushi; Takada, Kenta; Masumoto, Tomohiko; Anno, Izumi; Matsumura, Akira

    2015-01-01

    Introduction: The intent of this study was to differentiate intracranial tumors using the metabolite concentrations obtained by quantification with correction for T2 relaxation time, and to analyze whether the spectrum peak was generated by the existence of metabolites in proton magnetic resonance spectroscopy (MRS). Methods: All proton MRS studies were performed on a clinical 1.5T MR system. 7 normal volunteers and 57 patients (gliomas, metastases, meningiomas, acoustic neuromas, and pituitary adenomas) underwent single voxel proton MRS with different echo times (TE: 68, 136, 272 ms) for T2 correction of signal derived from metabolites and tissue water. With tissue water employed as an internal reference, the concentrations of metabolite (i.e. N-acetylaspartate (NAA), total creatine (t-Cr) and choline-containing compounds (Cho)) were calculated. Moreover, proton MRS data of previously published typical literatures were critically reviewed and compared with our data. Results: Extramedullary tumors were characterized by absence of NAA compared with intramedullary tumors. High-grade glioma differed from low-grade glioma by lower t-Cr concentrations. Metastasis differed from cystic glioblastoma by higher Cho concentrations, lower t-Cr concentrations, an absence of NAA, and a prominent Lipids peak. Based on these results and review of previous reports, we suggest a clinical pathway for the differentiation of intracranial tumors. Conclusion: The metabolite concentrations obtained by quantification with correction for T2 relaxation time, and to analyze whether the spectrum peak was generated by the existence of metabolites in proton MRS is useful for the diagnosis of the intracranial tumors

  19. Bone Scan

    Science.gov (United States)

    ... posts Join Mayo Clinic Connect Bone scan About Advertisement Mayo Clinic does not endorse companies or products. ... a Job Site Map About This Site Twitter Facebook Google YouTube Pinterest Mayo Clinic is a not- ...

  20. MRI Scans

    Science.gov (United States)

    Magnetic resonance imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body. Health care professionals use MRI scans to diagnose a variety of conditions, from ...

  1. Conservation of Moroccan manuscript papers aged 150, 200 and 800 years. Analysis by infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), and scanning electron microscopy energy dispersive spectrometry (SEM-EDS).

    Science.gov (United States)

    Hajji, Latifa; Boukir, Abdellatif; Assouik, Jamal; Lakhiari, Hamid; Kerbal, Abdelali; Doumenq, Pierre; Mille, Gilbert; De Carvalho, Maria Luisa

    2015-02-05

    The preservation of manuscripts and archive materials is a serious problem for librarians and restorers. Paper manuscript is subjected to numerous degradation factors affecting their conservation state. This research represents an attempt to evaluate the conservation restoration process applied in Moroccan libraries, especially the alkaline treatment for strengthening weakened paper. In this study, we focused on six samples of degraded and restored paper taken from three different Moroccan manuscripts aged 150, 200 and 800 years. In addition, the Japanese paper used in restoration has been characterized. A modern paper was also analyzed as reference. A three-step analytical methodology based on infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD) and scanning electron microscopy coupled to energy dispersive spectrometry (SEM-EDS) analysis was developed before and after restoration in order to determine the effect of the consolidation treatment on the paper structure. The results obtained by XRD and ATR-FTIR disclosed the presence of barium sulfate (BaSO4) in all restored paper manuscripts. The presence of calcium carbonate (CaCO3) in all considered samples was confirmed by FTIR spectroscopy. The application of de-acidification treatment causes significant changes connected with the increase of intensity mostly in the region 1426 cm(-1), assigned to the asymmetric and symmetric CO stretching mode of calcite, indicating the effectiveness of de-acidification procedure proved by the rise of the alkaline reserve content allowing the long term preservation of paper. Observations performed by SEM magnify the typical paper morphology and the structure of fibbers, highlighting the effect of the restoration process, manifested by the reduction of impurities. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Effects of Root Debridement With Hand Curettes and Er:YAG Laser on Chemical Properties and Ultrastructure of Periodontally-Diseased Root Surfaces Using Spectroscopy and Scanning Electron Microscopy.

    Science.gov (United States)

    Amid, Reza; Gholami, Gholam Ali; Mojahedi, Masoud; Aghalou, Maryam; Gholami, Mohsen; Mirakhori, Mahdieh

    2017-01-01

    Introduction: The efficacy of erbium-doped yttrium aluminum garnet (Er:YAG) laser for root debridement in comparison with curettes has been the subject of many recent investigations. Considering the possibility of chemical and ultra-structural changes in root surfaces following laser irradiation, this study sought to assess the effects of scaling and root planing (SRP) with curettes and Er:YAG laser on chemical properties and ultrastructure of root surfaces using spectroscopy and scanning electron microscopy (SEM). Methods: In this in vitro experimental study, extracted sound human single-rooted teeth (n = 50) were randomly scaled using manual curettes alone or in conjunction with Er:YAG laser at 100 and 150 mJ/pulse output energies. The weight percentages of carbon, oxygen, phosphorous and calcium remaining on the root surfaces were calculated using spectroscopy and the surface morphology of specimens was assessed under SEM. Data were analyzed using one-way analysis of variance (ANOVA). Results: No significant differences ( P > 0.05) were noted in the mean carbon, oxygen, phosphorous and calcium weight percentages on root surfaces following SRP using manual curettes with and without laser irradiation at both output energies. Laser irradiation after SRP with curettes yielded rougher surfaces compared to the use of curettes alone. Conclusion: Although laser irradiation yielded rougher surfaces, root surfaces were not significantly different in terms of chemical composition following SRP using manual curettes with and without Er:YAG laser irradiation. Er:YAG laser can be safely used as an adjunct to curettes for SRP.

  3. Real-time monitoring of benzene, toluene, and p-xylene in a photoreaction chamber with a tunable mid-infrared laser and ultraviolet differential optical absorption spectroscopy.

    Science.gov (United States)

    Parsons, Matthew T; Sydoryk, Ihor; Lim, Alan; McIntyre, Thomas J; Tulip, John; Jäger, Wolfgang; McDonald, Karen

    2011-02-01

    We describe the implementation of a mid-infrared laser-based trace gas sensor with a photoreaction chamber, used for reproducing chemical transformations of benzene, toluene, and p-xylene (BTX) gases that may occur in the atmosphere. The system performance was assessed in the presence of photoreaction products including aerosol particles. A mid-infrared external cavity quantum cascade laser (EC-QCL)-tunable from 9.41-9.88 μm (1012-1063 cm(-1))-was used to monitor gas phase concentrations of BTX simultaneously and in real time during chemical processing of these compounds with hydroxyl radicals in a photoreaction chamber. Results are compared to concurrent measurements using ultraviolet differential optical absorption spectroscopy (UV DOAS). The EC-QCL based system provides quantitation limits of approximately 200, 200, and 600 parts in 10(9) (ppb) for benzene, toluene, and p-xylene, respectively, which represents a significant improvement over our previous work with this laser system. Correspondingly, we observe the best agreement between the EC-QCL measurements and the UV DOAS measurements with benzene, followed by toluene, then p-xylene. Although BTX gas-detection limits are not as low for the EC-QCL system as for UV DOAS, an unidentified by-product of the photoreactions was observed with the EC-QCL, but not with the UV DOAS system.

  4. Differentiation of chronic and aggressive forms of periodontitis and of smokers and non-smokers by Fourier-transform infrared spectroscopy

    Directory of Open Access Journals (Sweden)

    Nihal Simsek Ozek

    2016-03-01

    Full Text Available Aim: To determine if Fourier-transform infrared spectroscopy (FTIR could distinguish chronic periodontitis (CP and aggressive periodontitis (AgP patients by cross-sectional salivary spectral analyses and to assess the potential confounding influence of smoking on discriminating spectral signatures. Methods: FTIR analysis of saliva collected from patients with CP (n = 18, 7 smokers, AgP (n = 23, 9 smokers was performed. Smoking status was confirmed by salivary cotinine analysis. Spectral band area analysis, hierarchical cluster analysis was performed. Results: Spectral analyses indicated significantly lower lipid, phospholipid, protein, amino acid, lactic acid, nucleic acid contents in smoker than non-smoker AgP group. Amino acid, phospholipid, lactic acid contents were significantly lower in smoker than non-smoker CP group. Thiocyanate levels successfully differentiated smokers from non-smokers, irrespective of periodontal status. Cluster analysis to discriminate smokers from non-smokers and CP from AgP was highly promising. Conclusions: FTIR can be employed to discriminate smokers from non-smokers and CP from AgP.

  5. Evaluation and differentiation of the Betulaceae birch bark species and their bioactive triterpene content using analytical FT-vibrational spectroscopy and GC-MS

    Directory of Open Access Journals (Sweden)

    Cîntă-Pînzaru Simona

    2012-07-01

    Full Text Available Abstract Background Aiming to obtain the highest triterpene content in the extraction products, nine bark samples from the forest abundant flora of Apuseni Mountains, Romania were Raman spectroscopically evaluated. Three different natural extracts from Betula pendula Roth birch bark have been obtained and characterized using Fourier transform vibrational spectra. Results This study shows that principal components of the birch tree extract can be rapidly recognized and differentiated based on their vibrational fingerprint band shape and intensity. The vibrational spectroscopy results are supported by the GC-MS data. Based on IR and Raman analysis, one can conclude that all the extracts, independent on the solvent(s used, revealed dominant betulin species, followed by lupeol. Conclusions Since Raman measurements could also be performed on fresh plant material, we demonstrated the possibility to apply the present results for the prediction of the highest triterpene content in bark species, for the selection of harvesting time or individual genotypes directly in the field, with appropriate portable Raman equipment.

  6. A differential optical absorption spectroscopy method for retrieval from ground-based Fourier transform spectrometers measurements of the direct solar beam

    Science.gov (United States)

    Huo, Yanfeng; Duan, Minzheng; Tian, Wenshou; Min, Qilong

    2015-08-01

    A differential optical absorption spectroscopy (DOAS)-like algorithm is developed to retrieve the column-averaged dryair mole fraction of carbon dioxide from ground-based hyper-spectral measurements of the direct solar beam. Different to the spectral fitting method, which minimizes the difference between the observed and simulated spectra, the ratios of multiple channel-pairs—one weak and one strong absorption channel—are used to retrieve from measurements of the shortwave infrared (SWIR) band. Based on sensitivity tests, a super channel-pair is carefully selected to reduce the effects of solar lines, water vapor, air temperature, pressure, instrument noise, and frequency shift on retrieval errors. The new algorithm reduces computational cost and the retrievals are less sensitive to temperature and H2O uncertainty than the spectral fitting method. Multi-day Total Carbon Column Observing Network (TCCON) measurements under clear-sky conditions at two sites (Tsukuba and Bremen) are used to derive xxxx for the algorithm evaluation and validation. The DOAS-like results agree very well with those of the TCCON algorithm after correction of an airmass-dependent bias.

  7. Investigation of laser-induced breakdown spectroscopy and multivariate analysis for differentiating inorganic and organic C in a variety of soils

    International Nuclear Information System (INIS)

    Martin, Madhavi Z.; Mayes, Melanie A.; Heal, Katherine R.; Brice, Deanne J.; Wullschleger, Stan D.

    2013-01-01

    Laser-induced breakdown spectroscopy (LIBS) along with multivariate analysis was used to differentiate between the total carbon (C), inorganic C, and organic C in a set of 58 different soils from 5 soil orders. A 532 nm laser with 45 mJ of laser power was used to excite the 58 samples of soil and the emission of all the elements present in the soil samples was recorded in a single spectrum with a wide wavelength range of 200–800 nm. The results were compared to the laboratory standard technique, e.g., combustion on a LECO-CN analyzer, to determine the true values for total C, inorganic C, and organic C concentrations. Our objectives were: 1) to determine the characteristic spectra of soils containing different amounts of organic and inorganic C, and 2) to examine the viability of this technique for differentiating between soils that contain predominantly organic and/or inorganic C content for a range of diverse soils. Previous work has shown that LIBS is an accurate and reliable approach to measuring total carbon content of soils, but it remains uncertain whether inorganic and organic forms of carbon can be separated using this approach. Total C and inorganic C exhibited correlation with rock-forming elements such as Al, Si, Fe, Ti, Ca, and Sr, while organic C exhibited minor correlation with these elements and a major correlation with Mg. We calculated a figure of merit (Mg/Ca) based on our results to enable differentiation between inorganic versus organic C. We obtained the LIBS validation prediction for total, inorganic, and organic C to have a coefficient of regression, r 2 = 0.91, 0.87, and 0.91 respectively. These examples demonstrate an advance in LIBS-based techniques to distinguish between organic and inorganic C using the full wavelength spectra. - Highlights: • This research has successfully identified the organic and inorganic carbon in soil. • Multivariate analysis was used to show success in building a statistical model. • Can be used to

  8. Dimyristoylphosphatidylcholine/C16 : 0-ceramide binary liposomes studied by differential scanning calorimetry and wide- and small-angle X-ray scattering

    DEFF Research Database (Denmark)

    Holopainen, J. M.; Lemmich, Jesper; Richter, F.

    2000-01-01

    hysteresis in the thermal phase behavior of ceramide-containing membranes. A partial phase diagram was constructed based on results from a combination of these two methods. DSC heating scans show that with increased X-cer the pretransition temperature T-P first increases, whereafter at X-cer > 0.06 it can...... of the studied compositions there is an endotherm in the region close to the T-m for DMPC. At X-cer greater than or equal to 0.03 a second endotherm is evident at higher temperatures, starting at 32.1 degrees C and reaching 54.6 degrees C at X-cer = 0.30. X-ray small-angle reflection heating scans reveal...... a lamellar phase within the temperature range of 15-60 degrees C, regardless of composition. The pretransition is observed up to X-cer repeat distance d increases from similar to 61 Angstrom at X-cer = 0.03, to 67 Angstrom at X-cer = 0...

  9. Ordered vortex lattice and intrinsic vortex core states in Bi sub 2 Sr sub 2 CaCu sub 2 O sub x studied by scanning tunneling microscopy and spectroscopy

    CERN Document Server

    Matsuba, K; Kosugi, N; Nishimori, H; Nishida, N

    2003-01-01

    The ordered vortex lattice in Bi sub 2 Sr sub 2 CaCu sub 2 O sub x (overdoped, T sub c = 83 K) has been observed for the first time at 4.2 K in 8 T by scanning tunneling spectroscopy (STS). The vortex lattice is short-range ordered in the length scale of 100 nm. The vortices form an almost square lattice with the sides parallel to the diagonal direction of the CuO sub 2 square lattice, that is, the nodal direction of the d sub x sub sup 2 sub - sub y sub sup 2 superconductor. In all of the vortex cores of the ordered lattice, the localized states are observed at +- 9 meV symmetrically in the superconducting gap and are clearly determined to be intrinsic to the vortex in Bi sub 2 Sr sub 2 CaCu sub 2 O sub x. The intensity is found to be electron-hole asymmetric.

  10. Xenon contrast CT-CBF scanning of the brain differentiates normal age-related changes from multi-infarct dementia and senile dementia of Alzheimer type

    International Nuclear Information System (INIS)

    Tachibana, H.; Meyer, J.S.; Okayasu, H.; Shaw, T.G.; Kandula, P.; Rogers, R.L.

    1984-01-01

    Local cerebral blood flow (LCBF) and partition coefficients (L lambda) were measured during inhalation of stable xenon gas with serial CT scanning among normal volunteers (N . 15), individuals with multi-infarct dementia (MID, N . 10), and persons with senile dementia of Alzheimer type (SDAT, N . 8). Mean gray matter flow values were reduced in both MID and SDAT. Age-related declines in LCBF values in normals were marked in frontal cortex and basal ganglia. LCBF values were decreased beyond normals in frontal and temporal cortices and thalamus in MID and SDAT, in basal ganglia only in MID. Unlike SDAT and age-matched normals, L lambda values were reduced in fronto-temporal cortex and thalamus in MID. Multifocal nature of lesions in MID was apparent. Coefficients of variation for LCBFs were greater in MID compared with SDAT and/or age-matched normals

  11. Estimation of hydrogen bondings in coal utilizing FTir and differential scanning calorimetry (DSC); FTir to DSC wo mochiita sekitannai suiso ketsugo no teiryoteki hyoka no kokoromi

    Energy Technology Data Exchange (ETDEWEB)

    Mae, K.; Miura, K. [Kyoto University, Kyoto (Japan). Faculty of Engineering

    1996-10-28

    With an objective to know coal condensation structure which has influence on coal conversion reaction, an attempt was made on quantitative evaluation of hydrogen bonding in coal. Using as test samples the VDC made from Taiheiyo coal swollen by tetralin and vacuum-dried, and its pyrolyzed char, DSC measurement and Fourier transform infrared spectroscopy (FT) were performed. An FT spectrum comparison revealed that the VDC swollen at 220{degree}C has the hydrogen bonding relaxed partly from the original coal. However, since the change is in a huge coal molecular structure restraining space, it has stopped at relaxation of the bonding energy without causing separation as far as free radicals. On the other hand, the DSC curve shows that the VDC has slower endothermic velocity than the original coal. In other words, the difference in heat absorption amounts in both materials is equivalent to the difference of enthalpy ({Delta} H) of both materials, which corresponds to the relaxation of the hydrogen bonding. Therefore, the {Delta} H was related to wavenumber shift of the FT spectra (which corresponds to change in the hydrogen bonding condition). By using this relationship, a method for evaluating hydrogen bonding distribution was proposed from an O-H contracting vibration change that can be measured by using the FT spectra and a thermal change that can be measured by using the DSC. 3 refs., 7 figs.

  12. The use of Differential Scanning Calorimetry (DSC) to characterize phase diagrams of ionic mixtures of 1-n-butyl-3-methylimidazolium chloride and niobium chloride or zinc chloride

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Melquizedeque B.; Umpierre, Alexandre P.; Santos Jr, Vianney O.; Soares, Valerio C.D. [Laboratorio de Materiais e Combustiveis - Instituto de Quimica da Universidade de Brasilia, C.P. 04478, CEP 70904-970, Brasilia, DF (Brazil); Dupont, Jairton [Laboratorio de Catalise Molecular - Instituto de Quimica da Universidade Federal do Rio Grande do Sul, C.P. 15003, CEP 91501-970, Porto Alegre, RS (Brazil); Rubim, Joel C. [Laboratorio de Materiais e Combustiveis - Instituto de Quimica da Universidade de Brasilia, C.P. 04478, CEP 70904-970, Brasilia, DF (Brazil); Suarez, Paulo A.Z., E-mail: psuarez@unb.br [Laboratorio de Materiais e Combustiveis - Instituto de Quimica da Universidade de Brasilia, C.P. 04478, CEP 70904-970, Brasilia, DF (Brazil)

    2010-04-20

    The thermal behavior of the BMICl/NbCl{sub 5} and BMICl/ZnCl{sub 2} mixtures was investigated by DSC and correlated with previous studies using Raman spectroscopy. Combining both results, it was possible to built the phase diagram for these mixtures and suggest the formation of different compounds and the equilibria in the euthetic mixtures. The phase diagram of BMICl and NbCl{sub 5} mixture showed that probably only one compound is formed at X{sub NbCl5} = 0.50 (BMINbCl{sub 6}) and euthetic mixtures are present in the 0 {<=} X{sub NbCl5} {<=} 0.50 composition range. For the BMICl and ZnCl{sub 2}, four different compounds were detected: (BMI){sub 2}(ZnCl{sub 4}) for X{sub ZnCl2} = 0.35; (BMI){sub 2}(Zn{sub 2}Cl{sub 6}); (BMI){sub 2}(Zn{sub 3}Cl{sub 8}) and (BMI){sub 2}(Zn{sub 4}Cl{sub 10}) for X{sub ZnCl2} = 0.70, and between these isoplets euthetic mixtures are formed.

  13. Scanning table

    CERN Multimedia

    1960-01-01

    Before the invention of wire chambers, particles tracks were analysed on scanning tables like this one. Today, the process is electronic and much faster. Bubble chamber film - currently available - (links can be found below) was used for this analysis of the particle tracks.

  14. TU-C-12A-12: Differentiating Bone Lesions and Degenerative Joint Disease in NaF PET/CT Scans Using Machine Learning

    International Nuclear Information System (INIS)

    Perk, T; Bradshaw, T; Muzahir, S; Jeraj, R; Meyer, E

    2014-01-01

    Purpose: [F-18]NaF PET can be used to image bone metastases; however, tracer uptake in degenerative joint disease (DJD) often appears similar to metastases. This study aims to develop and compare different machine learning algorithms to automatically identify regions of [F-18]NaF scans that correspond to DJD. Methods: 10 metastatic prostate cancer patients received whole body [F-18]NaF PET/CT scans prior to treatment. Image segmentation resulted in 852 ROIs, 69 of which were identified by a nuclear medicine physician as DJD. For all ROIs, various PET and CT textural features were computed. ROIs were divided into training and testing sets used to train eight different machine learning classifiers. Classifiers were evaluated based on receiver operating characteristics area under the curve (AUC), sensitivity, specificity, and positive predictive value (PPV). We also assessed the added value of including CT features in addition to PET features for training classifiers. Results: The training set consisted of 37 DJD ROIs with 475 non-DJD ROIs, and the testing set consisted of 32 DJD ROIs with 308 non-DJD ROIs. Of all classifiers, generalized linear models (GLM), decision forests (DF), and support vector machines (SVM) had the best performance. AUCs of GLM (0.929), DF (0.921), and SVM (0.889) were significantly higher than the other models (p<0.001). GLM and DF, overall, had the best sensitivity, specificity, and PPV, and gave a significantly better performance (p<0.01) than all other models. PET/CT GLM classifiers had higher AUC than just PET or just CT. GLMs built using PET/CT information had superior or comparable sensitivities, specificities and PPVs to just PET or just CT. Conclusion: Machine learning algorithms trained with PET/CT features were able to identify some cases of DJD. GLM outperformed the other classification algorithms. Using PET and CT information together was shown to be superior to using PET or CT features alone. Research supported by the Prostate

  15. MR spectroscopy of intracranial tuberculomas: A singlet peak at 3.8 ppm as potential marker to differentiate them from malignant tumors.

    Science.gov (United States)

    Morales, Humberto; Alfaro, David; Martinot, Carlos; Fayed, Nicolas; Gaskill-Shipley, Mary

    2015-06-01

    The diagnosis of intracranial tuberculomas is often challenging. Our purpose is to describe the most common metabolic patterns of tuberculomas by MR spectroscopy (MRS) with emphasis on potential specific markers. Single-voxel MRS short echo time was performed in 13 cases of tuberculomas proven by histology and/or response to anti-mycobacterial therapy. For comparison MRS was also performed in 19 biopsy-proven malignant tumors (13 high-grade gliomas and six metastasis). Presence of metabolic peaks was assessed visually and categorical variables between groups were compared using chi-square. Metabolite ratios were compared using Mann-Whitney test and diagnostic accuracy of the metabolite ratios was compared using receiver-operating characteristic (ROC) curves analysis. Spectroscopic peaks representing lipids and glutamate/glutamine (Glx) as well as a peak at ∼3.8 ppm were well defined in 77% (10/13), 77% (10/13) and 69% (nine of 13) of tuberculomas, respectively. Lipid and Glx peaks were also present in most of the malignant lesions, 79% (15/19) and 74% (14/19) respectively. However, a peak at ∼3.8 ppm was present in only 10% (two of 19) of the tumor cases (p values between 1.7-1.9 for Cho/Cr and 0.8-0.9 for mI/Cr provided high specificity (91% for both metabolites) and adequate sensitivity (75% and 80%, respectively) for discrimination of malignant lesions. A singlet peak at ∼3.8 ppm is present in the majority of tuberculomas and absent in most malignant tumors, potentially a marker to differentiate these lesions. The assignment of the peak is difficult from our analysis; however, guanidinoacetate (Gua) is a possibility. Higher Cho/Cr and mI/Cr ratios should favor malignant lesions over tuberculomas. The presence of lipids and Glx is non-specific. © The Author(s) 2015.

  16. Differential Associations of Socioeconomic Status With Global Brain Volumes and White Matter Lesions in African American and White Adults: the HANDLS SCAN Study.

    Science.gov (United States)

    Waldstein, Shari R; Dore, Gregory A; Davatzikos, Christos; Katzel, Leslie I; Gullapalli, Rao; Seliger, Stephen L; Kouo, Theresa; Rosenberger, William F; Erus, Guray; Evans, Michele K; Zonderman, Alan B

    2017-04-01

    The aim of the study was to examine interactive relations of race and socioeconomic status (SES) to magnetic resonance imaging (MRI)-assessed global brain outcomes with previously demonstrated prognostic significance for stroke, dementia, and mortality. Participants were 147 African Americans (AAs) and whites (ages 33-71 years; 43% AA; 56% female; 26% below poverty) in the Healthy Aging in Neighborhoods of Diversity across the Life Span SCAN substudy. Cranial MRI was conducted using a 3.0 T unit. White matter (WM) lesion volumes and total brain, gray matter, and WM volumes were computed. An SES composite was derived from education and poverty status. Significant interactions of race and SES were observed for WM lesion volume (b = 1.38; η = 0.036; p = .028), total brain (b = 86.72; η = 0.042; p brain volumes than all other groups (albeit within normal range). Low SES was associated with greater WM pathology-a marker for increased stroke risk-in AAs. Higher SES was associated with greater total brain volume-a putative global indicator of brain health and predictor of mortality-in whites. Findings may reflect environmental and interpersonal stressors encountered by AAs and those of lower SES and could relate to disproportionate rates of stroke, dementia, and mortality.

  17. Local study of the Mg{sub 1-x}Al{sub x}B{sub 2} single crystals by scanning tunneling spectroscopy in magnetic field up to 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Giubileo, F. [CNR-INFM Laboratorio Regionale SUPERMAT, Dipartimento di Fisica ' E.R. Caianiello' , Universita degli Studi di Salerno, via Salvador Allende, 84081 Baronissi, SA (Italy)], E-mail: giubileo@sa.infn.it; Bobba, F.; Scarfato, A.; Cucolo, A.M. [CNR-INFM Laboratorio Regionale SUPERMAT, Dipartimento di Fisica ' E.R. Caianiello' , Universita degli Studi di Salerno, via Salvador Allende, 84081 Baronissi, SA (Italy); Kohen, A.; Roditchev, D. [Institut des Nanosciences de Paris, INSP, Universite P. et M. Curie Paris 6, CNRS, UMR 75-88, Paris (France); Zhigadlo, N.D.; Karpinski, J. [Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich (Switzerland)

    2008-04-01

    We have performed local tunneling spectroscopy on high quality Mg{sub 1-x}Al{sub x}B{sub 2} single crystals by means of variable temperature scanning tunneling spectroscopy in magnetic field up to 3 Tesla. Single gap conductance spectra due to c-axis tunneling were extensively measured, probing different amplitudes of the three-dimensional {delta}{sub {pi}} as a function of Al content (i.e. as a function of the critical temperature T{sub C}). Temperature and magnetic field dependences of the conductance spectra were studied in S-I-N configuration: the effect of the doping resulted in a monotonous reduction of the locally measured T{sub C} down to 24 K for x = 0.2. The magnetic field dependence was studied in a local way: An estimation for upper critical field H{sub c2} was inferred from the evolution of the tunneling spectra with the field perpendicular to the sample surface, for different doping levels. The high spatial resolution of the STS technique allowed us to evidence possible non-homogeneities of the superconducting properties on the sample surface with variation of in the same sample depending on different local levels of doping. The locally measured upper critical field resulted to vary for different dopings, and the maximum value H{sub c2}{approx_equal}3T was found for samples with T{sub C}=33 K. The evolution of the density of states (DOS) was found to be characterized by two distinct regimes separated by a crossover region. Our results indicate a rapid suppression of the intrinsic term in {pi}-band superconductivity for 0 T < B < 0.5 T. At high fields (0.8 T < B < 3 T) the superconductivity in the {pi}-band survives uniquely due to the coupling to the {sigma}-band. The shape of tunneling spectra suggests an important role played by the quasiparticle inter-band scattering.

  18. Scanning holograms

    International Nuclear Information System (INIS)

    Natali, S.

    1984-01-01

    This chapter reports on the scanning of 1000 holograms taken in HOBC at CERN. Each hologram is triggered by an interaction in the chamber, the primary particles being pions at 340 GeV/c. The aim of the experiment is the study of charm production. The holograms, recorded on 50 mm film with the ''in line'' technique, can be analyzed by shining a parallel expanded laser beam through the film, obtaining immediately above it the real image of the chamber which can then be scanned and measured with a technique half way between emulsions and bubble chambers. The results indicate that holograms can be analyzed as quickly and reliably as in other visual techniques and that to them is open the same order of magnitude of large scale experiments

  19. Study of the stability of 5,10,15,20-tetraphenylporphine (TPP) and metalloporphyrins NiTPP, CoTPP, CuTPP, and ZnTPP by differential scanning calorimetry and thermogravimetry

    International Nuclear Information System (INIS)

    Gamboa, Minerva; Campos, Myriam; Torres, Luis Alfonso

    2010-01-01

    In this work, the stability of 5,10,15,20-tetraphenylporphine (TPP) and its metallic derivatives, NiTPP, CoTPP, CuTPP, and ZnTPP has been studied through differential scanning calorimetry and thermogravimetry. The decomposition temperatures are (712, 710, 708, 702, and 671) K for NiTPP, CoTPP, CuTPP, ZnTPP, and TPP, respectively. These values are in correspondence with the N-M bond length d M-N , of the metalloporphyrins. The corresponding molar enthalpies of melting Δ fus H m , were determined as (58, 57, 55, 52, and 44) kJ . mol -1 for the same series. These values are discussed in terms of the crystallographic features in the solid state.

  20. Early in-flight detection of SO2 via Differential Optical Absorption Spectroscopy: a feasible aviation safety measure to prevent potential encounters with volcanic plumes

    Directory of Open Access Journals (Sweden)

    U. Platt

    2011-09-01

    Full Text Available Volcanic ash constitutes a risk to aviation, mainly due to its ability to cause jet engines to fail. Other risks include the possibility of abrasion of windshields and potentially serious damage to avionic systems. These hazards have been widely recognized since the early 1980s, when volcanic ash provoked several incidents of engine failure in commercial aircraft. In addition to volcanic ash, volcanic gases also pose a threat. Prolonged and/or cumulative exposure to sulphur dioxide (SO2 or sulphuric acid (H2SO4 aerosols potentially affects e.g. windows, air frame and may cause permanent damage to engines. SO2 receives most attention among the gas species commonly found in volcanic plumes because its presence above the lower troposphere is a clear proxy for a volcanic cloud and indicates that fine ash could also be present. Up to now, remote sensing of SO2 via Differential Optical Absorption Spectroscopy (DOAS in the ultraviolet spectral region has been used to measure volcanic clouds from ground based, airborne and satellite platforms. Attention has been given to volcanic emission strength, chemistry inside volcanic clouds and measurement procedures were adapted accordingly. Here we present a set of experimental and model results, highlighting the feasibility of DOAS to be used as an airborne early detection system of SO2 in two spatial dimensions. In order to prove our new concept, simultaneous airborne and ground-based measurements of the plume of Popocatépetl volcano, Mexico, were conducted in April 2010. The plume extended at an altitude around 5250 m above sea level and was approached and traversed at the same altitude with several forward looking DOAS systems aboard an airplane. These DOAS systems measured SO2 in the flight direction and at ±40 mrad (2.3° angles relative to it in both, horizontal and vertical directions. The approaches started at up to 25 km distance to the plume and SO2 was measured at all times well above the

  1. MR spectroscopy of intracranial tuberculomas: A singlet peak at 3.8 ppm as potential marker to differentiate them from malignant tumors

    Science.gov (United States)

    Alfaro, David; Martinot, Carlos; Fayed, Nicolas; Gaskill-Shipley, Mary

    2015-01-01

    Purpose The diagnosis of intracranial tuberculomas is often challenging. Our purpose is to describe the most common metabolic patterns of tuberculomas by MR spectroscopy (MRS) with emphasis on potential specific markers. Methods Single-voxel MRS short echo time was performed in 13 cases of tuberculomas proven by histology and/or response to anti-mycobacterial therapy. For comparison MRS was also performed in 19 biopsy-proven malignant tumors (13 high-grade gliomas and six metastasis). Presence of metabolic peaks was assessed visually and categorical variables between groups were compared using chi-square. Metabolite ratios were compared using Mann-Whitney test and diagnostic accuracy of the metabolite ratios was compared using receiver-operating characteristic (ROC) curves analysis. Results Spectroscopic peaks representing lipids and glutamate/glutamine (Glx) as well as a peak at ∼3.8 ppm were well defined in 77% (10/13), 77% (10/13) and 69% (nine of 13) of tuberculomas, respectively. Lipid and Glx peaks were also present in most of the malignant lesions, 79% (15/19) and 74% (14/19) respectively. However, a peak at ∼3.8 ppm was present in only 10% (two of 19) of the tumor cases (p < 0.001). Higher Cho/Cr and mI/Cr ratios helped discriminate malignant lesions with an area under the ROC curve of 0.86 (SE: 0.078, p < 0.002, CI: 0.7–1) and 0.8 (SE: 0.1, p < 0.009, CI: 0.6–1), respectively. Threshold values between 1.7–1.9 for Cho/Cr and 0.8–0.9 for mI/Cr provided high specificity (91% for both metabolites) and adequate sensitivity (75% and 80%, respectively) for discrimination of malignant lesions. Conclusion A singlet peak at ∼3.8 ppm is present in the majority of tuberculomas and absent in most malignant tumors, potentially a marker to differentiate these lesions. The assignment of the peak is difficult from our analysis; however, guanidinoacetate (Gua) is a possibility. Higher Cho/Cr and mI/Cr ratios should favor malignant lesions

  2. The role of FDG-PET/CT in differentiated thyroid cancer patients with negative iodine-131 whole-body scan and elevated anti-Tg level.

    Science.gov (United States)

    Asa, Sertac; Aksoy, Sabire Yılmaz; Vatankulu, Betül; Aliyev, Anar; Uslu, Lebriz; Ozhan, Meftune; Sager, Sait; Halac, Metin; Sonmezoglu, Kerim

    2014-12-01

    In the follow-up of differentiated thyroid cancer (DTC) after a successful total-near total thyroidectomy and I-131 ablation therapy, anti-thyroglobulin antibodies (anti-Tg) may be persistently or progressively increased in the patients with an undetectable serum thyroglobulin (Tg) level. In these cases, further investigation was performed to search for recurrence/metastases. The aim of our study was clarifying the role of FDG-PET/CT in detecting recurrence/metastasis in patients with DTC with negative serum Tg and elevated anti-Tg level. A total of 40 patients (32 female, 8 male; mean age: 43.15 years (22-65); mean age at diagnosis: 39.08 (16-64)) with DTC who had undetectable serum Tg and elevated anti-Tg level after a successful initial therapy were included in the study. All of the patients had serum anti-Tg of >40 IU/ml and underwent FDG-PET/CT to search for recurrence/metastasis. Twenty patients (50 %) had recurrence/metastasis on FDG-PET/CT while the other 20 had no pathologic findings. Of the 20 patients who had positive FDG-PET/CT, 12 had a histopathological final diagnosis of which 11 were true positive (TP) and 1 was false positive (FP). On the other hand, 16 of the 40 patients had a histopathological final diagnosis of which 11/16 had TP, 1/16 FP, 3/16 false negative (FN) and 1/16 true negative (TN) findings by PET/CT. The final diagnosis was made by clinical follow-up in the remaining 24 patients. Of these, 8 patients were PET positive, and in 1 (12.5 %) of 8 patients a decrease in serum anti-Tg level, in 2 (25 %) patients a saw-toothed pattern and in 5 (62.5 %) a progressive increase in the serum anti-Tg level were noted during the follow-up. Of the 16 of 24 patients who were diagnosed by clinical follow-up, in 8 a (50 %) decrease in serum anti-Tg level, in 6 (37.5 %) a saw-toothed pattern, and in 2 (12.5 %) a progressively increased anti-Tg level was seen. Of the 40 patients, 14 (35 %) had a diagnosis of recurrence/metastasis finally, with

  3. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Thyroid Scan and Uptake Thyroid scan and uptake uses ... the Thyroid Scan and Uptake? What is a Thyroid Scan and Uptake? A thyroid scan is a ...

  4. Compatibilidad química por calorimetría diferencial de barrido y termogravimetría del auranofin tabletas 3 mg Chemical compatibility of 3 mg Auranofin tablets demonstrated by differential scanning calorimetry and thermogravimetry

    Directory of Open Access Journals (Sweden)

    Luis Octavio Martínez Álvarez

    2011-03-01

    Full Text Available Como parte de la pre-estabilidad de la preformulación de auranofin tabletas, se realizó un estudio de compatibilidad química, para lo cual se emplearon técnicas de análisis térmico como la calorimetría diferencial de barrido y la termogravimetría. Previo a dichos estudios se caracterizó térmicamente por calorimetría diferencial de barrido el principio activo y cada uno de los excipientes. Posteriormente se procedió a la realización del estudio de compatibilidad química, mediante la preparación de mezclas físicas binarias entre el principio activo y cada uno de los excipientes. Se detectó por ambos métodos que el principio activo tuvo una transición física de fusión, no reportada en la literatura, lo que permitió poder calcular su pureza por calorimetría diferencial de barrido. Mediante la técnica calorimétrica fue posible inferir la ausencia de incompatibilidad química entre el principio activo y los excipientes estudiados. Además, mediante el cálculo de la energía de activación se estableció el siguiente orden de estabilidad térmica: auranofin:PVP> auranofin:lactosa> auranofin:explotab> auranofin:estearato> auranofin:aerosil> auranofin:celulosa, por lo que se recomienda el uso de estos excipientes en la elaboración de la formulación farmacéutica.As part of the pre-stability study of the Auranofin tablet pre-formulation, a chemical compatibility study was conducted using thermal analysis techniques such as the differential scanning calorimetry and the thermogravimetry. Prior to these studies, the active principle and each of the excipients were thermally characterized with the aid of the differential scanning calorimetry. Then, there proceeded to carry out the chemical compatibility study by preparing binary physical mixtures between the active principle and each of the excipients. Both methods showed that the active principle had a melting physical transition, not reported in the literature, which allowed

  5. Electron spectroscopy

    International Nuclear Information System (INIS)

    Hegde, M.S.

    1979-01-01

    An introduction to the various techniques in electron spectroscopy is presented. These techniques include: (1) UV Photoelectron spectroscopy, (2) X-ray Photoelectron spectroscopy, (3) Auger electron spectroscopy, (4) Electron energy loss spectroscopy, (5) Penning ionization spectroscopy and (6) Ion neutralization spectroscopy. The radiations used in each technique, the basis of the technique and the special information obtained in structure determination in atoms and molecules by each technique are summarised. (A.K.)

  6. Development and Deployment of a Compact Eye-Safe Scanning Differential absorption Lidar (DIAL) for Spatial Mapping of Carbon Dioxide for Monitoring/Verification/Accounting at Geologic Sequestration Sites

    Energy Technology Data Exchange (ETDEWEB)

    Repasky, Kevin

    2014-03-31

    A scanning differential absorption lidar (DIAL) instrument for monitoring carbon dioxide has been developed. The laser transmitter uses two tunable discrete mode laser diodes (DMLD) operating in the continuous wave (cw) mode with one locked to the online absorption wavelength and the other operating at the offline wavelength. Two in-line fiber optic switches are used to switch between online and offline operation. After the fiber optic switch, an acousto- optic modulator (AOM) is used to generate a pulse train used to injection seed an erbium doped fiber amplifier (EDFA) to produce eye-safe laser pulses with maximum pulse energies of 66 {micro}J, a pulse repetition frequency of 15 kHz, and an operating wavelength of 1.571 {micro}m. The DIAL receiver uses a 28 cm diameter Schmidt-Cassegrain telescope to collect that backscattered light, which is then monitored using a photo-multiplier tube (PMT) module operating in the photon counting mode. The DIAL instrument has been operated from a laboratory environment on the campus of Montana State University, at the Zero Emission Research Technology (ZERT) field site located in the agricultural research area on the western end of the Montana State University campus, and at the Big Sky Carbon Sequestration Partnership site located in north-central Montana. DIAL data has been collected and profiles have been validated using a co-located Licor LI-820 Gas Analyzer point sensor.

  7. Forensic Scanning Electron Microscope

    Science.gov (United States)

    Keeley, R. H.

    1983-03-01

    The scanning electron microscope equipped with an x-ray spectrometer is a versatile instrument which has many uses in the investigation of crime and preparation of scientific evidence for the courts. Major applications include microscopy and analysis of very small fragments of paint, glass and other materials which may link an individual with a scene of crime, identification of firearms residues and examination of questioned documents. Although simultaneous observation and chemical analysis of the sample is the most important feature of the instrument, other modes of operation such as cathodoluminescence spectrometry, backscattered electron imaging and direct x-ray excitation are also exploited. Marks on two bullets or cartridge cases can be compared directly by sequential scanning with a single beam or electronic linkage of two instruments. Particles of primer residue deposited on the skin and clothing when a gun is fired can be collected on adhesive tape and identified by their morphology and elemental composition. It is also possible to differentiate between the primer residues of different types of ammunition. Bullets may be identified from the small fragments left behind as they pass through the body tissues. In the examination of questioned documents the scanning electron microscope is used to establish the order in which two intersecting ink lines were written and to detect traces of chemical markers added to the security inks on official documents.

  8. Head CT scan

    Science.gov (United States)

    ... CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - ... Head CT is done in the hospital or radiology center. You lie on a narrow table that ...

  9. Pelvic CT scan

    Science.gov (United States)

    CAT