Science.gov

Sample records for quantitative uv-visible spectroscopy

  1. Using multiwavelength UV-visible spectroscopy for the characterization of red blood cells: An investigation of hypochromism

    NASA Astrophysics Data System (ADS)

    Nonoyama, Akihisa

    Particle analysis using multiwavelength UV-visible spectroscopy provides the potential for extracting quantitative red blood cell information, such as hemoglobin concentration, cell size, and cell count. However, if there is a significant presence of hypochromism as a result of the concentrated hemoglobin (physiological value of 33%), successful quantification of red cell values would require a correction. Hypochromism has been traditionally defined as a decrease in absorption relative to the values expected from the Beer-Lambert Law due to electronic interactions of chromophores residing in close proximity of one another. This phenomenon has been suggested to be present in macroscopic systems composed of strong chromophores such as nucleic acids, chlorophyll, and hemoglobin. The study presented in this dissertation examines the presence of hypochromism in red blood cells as a part of a larger goal to qualitatively and quantatively characterize red blood cells using multiwavelength UV-visible spectroscopy. The strategy of the study was three-fold: (1) to determine the instrumental configuration that would provide the most complete information in the acquired spectra, (2) to develop an experimental model system in which the hemoglobin content in red blood cells could be modified to various concentrations, and (3) to implement an interpretation model based on light scattering theory (which accounts for both the scattering and absorption components of the optical density spectrum) to provide quantitative information for the experimental system. By this process, hypochromicity was redefined into two categories with molecular hypochromicity representing the traditional definition and macroscopic hypochromicity being an attenuation of the absorption component due to a scattering-related effect. Successful simulations of experimental red cell spectra containing various amounts of hemoglobin were obtained using the theoretical model. Furthermore, successful quantitative interpretation of the red blood cell spectra was achieved in the context of corpuscular hemoglobin concentration, corpuscular volume, and cell count solely by accounting for the scattering and absorption effects of the particle, indicating that molecular hypochromicity was insignificant in this macroscopic system.

  2. Simple and Precise Quantification of Iron Catalyst Content in Carbon Nanotubes Using UV/Visible Spectroscopy

    PubMed Central

    Agustina, Elsye; Goak, Jeungchoon; Lee, Suntae; Seo, Youngho; Park, Jun-Young; Lee, Naesung

    2015-01-01

    Iron catalysts have been used widely for the mass production of carbon nanotubes (CNTs) with high yield. In this study, UV/visible spectroscopy was used to determine the Fe catalyst content in CNTs using a colorimetric technique. Fe ions in solution form red–orange complexes with 1,10-phenanthroline, producing an absorption peak at ?=510?nm, the intensity of which is proportional to the solution Fe concentration. A series of standard Fe solutions were formulated to establish the relationship between optical absorbance and Fe concentration. Many Fe catalysts were microscopically observed to be encased by graphitic layers, thus preventing their extraction. Fe catalyst dissolution from CNTs was investigated with various single and mixed acids, and Fe concentration was found to be highest with CNTs being held at reflux in HClO4/HNO3 and H2SO4/HNO3 mixtures. This novel colorimetric method to measure Fe concentrations by UV/Vis spectroscopy was validated by inductively coupled plasma optical emission spectroscopy, indicating its reliability and applicability to asses Fe content in CNTs. PMID:26491641

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

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

    NASA Astrophysics Data System (ADS)

    Tang, Shihua; Wang, Baiyang; Li, Youqun

    2015-04-01

    The chemical kinetics on gelatin-CdS direct conjugates has been systematically investigated as a function of different temperature and reactant concentration (i.e. Cd2+, S2- and gelatin) by UV-visible spectroscopy, for the first time. The nonlinear fitting and the differential method were used to calculate the initial rate based on the absorbance-time data. A double logarithmic linear equation for calculating the rate constant (k) and the reaction order (n) was introduced. The reaction kinetic parameters (n, k, Ea, and Z) and activation thermodynamic parameters (?G?, ?H?, and ?S?) were obtained from variable temperature kinetic studies. The overall rate equation allowing evaluation of conditions that provide required reaction rate could be expressed as:

  5. In situ UV-visible reflection absorption wavelength modulation spectroscopy of species irreversibly adsorbed on electrode surfaces

    SciTech Connect

    Kim, Sunghyun; Scherson, D.A. )

    1992-12-15

    A method is herein described for the in situ detection of species adsorbed on electrode surfaces which employs a vibrating grating to modulate the wavelength of the incident light. This technique denoted as reflection absorption wavelength modulation spectroscopy (RAWMS) has made it possible to obtain at a fixed electrode potential normalized, differential UV-visible spectra of a single, irreversibly adsorbed monolayer of cobalt tetrasulfonated phthalocyanine (Co[sup II]TsPc) on the basal plane of highly oriented pyrolytic graphite (HOPG(bp)) and of methylene blue (MB) on graphite. The (wavelength) integrated difference RAWMS spectra for these adsorbed species were remarkably similar to those observed for the same compounds in aqueous solutions when present in the monomeric form. Complementary wavelength modulation experiments involving a conventional transmission geometry have shown that the instrument involved in the in situ RAWMS measurements is capable of resolving absorbance changes on the order of 0.002 units. 20 refs.

  6. Quantitation of cutaneous inflammation induced by reactive species generated by UV-visible irradiation of rose bengal

    SciTech Connect

    Ranadive, N.S.; Menon, I.A.; Shirwadkar, S.; Persad, S.D. )

    1989-10-01

    The present studies were undertaken to quantitate the initial inflammatory response produced by the photo-generated reactive species in rabbit skin. Rose bengal (RB), a photosensitizer dye, was injected into the skin sites at various concentrations and exposed to UV-visible light for 30-120 min. The increase in vascular permeability and the accumulation of PMNs were investigated using 125I-labeled albumin and 51Cr-labeled PMNs. RB at a concentration of 1 nmol with 120-min exposure to light enhanced vascular permeability by 3.7 times and accumulation of PMNs by 3.3 times. As low as 0.01 nmol of RB produced discernible effects. beta-Carotene (0.1 nmole) inhibited the inflammatory response by 75-100%, suggesting that the reactive species involved in this response was predominantly singlet oxygen. The increase in vascular permeability was inhibited by 48-70% by 25 micrograms of chlorpheniramine maleate. It is therefore suggested that histamine plays a major role in the initial vascular response. The studies demonstrate that this rabbit model is suitable for the quantitation of photoinduced inflammatory response which is not observable by gross anatomic procedures.

  7. Artificial nose, NIR and UV-visible spectroscopy for the characterisation of the PDO Chianti Classico olive oil.

    PubMed

    Forina, M; Oliveri, P; Bagnasco, L; Simonetti, R; Casolino, M C; Nizzi Grifi, F; Casale, M

    2015-11-01

    An authentication study of the Italian PDO (Protected Designation of Origin) olive oil Chianti Classico, based on artificial nose, near-infrared and UV-visible spectroscopy, with a set of samples representative of the whole Chianti Classico production area and a considerable number of samples from other Italian PDO regions was performed. The signals provided by the three analytical techniques were used both individually and jointly, after fusion of the respective variables, in order to build a model for the Chianti Classico PDO olive oil. Different signal pre-treatments were performed in order to investigate their importance and their effects in enhancing and extracting information from experimental data, correcting backgrounds or removing baseline variations. Stepwise-Linear Discriminant Analysis (STEP-LDA) was used as a feature selection technique and, afterward, Linear Discriminant Analysis (LDA) and the class-modelling technique Quadratic Discriminant Analysis-UNEQual dispersed classes (QDA-UNEQ) were applied to sub-sets of selected variables, in order to obtain efficient models capable of characterising the extra virgin olive oils produced in the Chianti Classico PDO area. PMID:26452929

  8. Sensitive determination of trace mercury by UV-visible diffuse reflectance spectroscopy after complexation and membrane filtration-enrichment.

    PubMed

    Yin, Changhai; Iqbal, Jibran; Hu, Huilian; Liu, Bingxiang; Zhang, Lei; Zhu, Bilin; Du, Yiping

    2012-09-30

    A simple, sensitive and selective solid phase reflectometry method is proposed for the determination of trace mercury in aqueous samples. The complexation reagent dithizone was firstly injected into the properly buffered solution with vigorous stirring, which started a simultaneous formation of nanoparticles suspension of dithizone and its complexation reaction with the mercury(II) ions to make Hg-dithizone nanoparticles. After a definite time, the mixture was filtered with membrane, and then quantified directly on the surface of the membrane by using integrating sphere accessory of the UV-visible spectrophotometer. The quantitative analysis was carried out at a wavelength of 485 nm since it yielded the largest difference in diffuse reflectance spectra before and after reaction with mercury(II).A good linear correlation in the range of 0.2-4.0 ?g/L with a squared correlation coefficient (R(2)) of 0.9944 and a detection limit of 0.12 ?g/L were obtained. The accuracy of the method was evaluated by the analysis of spiked mercury(II) concentrations determined using this method along with those determined by the atomic fluorescence mercury vapourmeter and the results obtained were in good agreement. The proposed method was applied to the determination of mercury in tap water and river water samples with the recovery in an acceptable range (95.7-105.3%). PMID:22831998

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

    SciTech Connect

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

    2001-01-01

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

  10. Photophysics of Genistein isoflavone: Solvent and concentration effects studied by UV-visible spectroscopy and theoretical simulation

    NASA Astrophysics Data System (ADS)

    Benthami, K.; Lyazidi, S. Ait; Haddad, M.; Choukrad, M.; Bennetau, B.; Shinkaruk, S.

    2009-10-01

    Genistein isoflavone is shown to exist in two different conformations which are the 90° completely twisted geometry and the 50° less twisted one. Specific interactions with the solvent cage as well as self-association processes seem shifting the isoflavone from the perpendicular conformation towards the less twisted one. The theoretical simulation, using analytical atom-atom pair potential, predicts a self-dimer in a slipped non-sandwich, face to river, perpendicular structure. From the UV-visible photophysics investigations it is revealed that monomeric species cannot exist alone even at very low solute concentration (˜10 -6 M), the self-association process occurs already in this concentration range.

  11. Pressure induced structural change in PbPc studied by infrared and UV visible spectroscopy and theoretical calculation

    NASA Astrophysics Data System (ADS)

    Sakata, Masafumi; Sumimoto, Michinori; Gushima, Mika; Fujimoto, Hitoshi; Matsuzaki, Susumu

    2002-02-01

    Lead phthalocyanine (PbPc) has a non-planar 'shuttle-cock' structure with a C4 v molecular symmetry and forms a one-dimensional column in the crystal. We measured infrared and UV-visible spectra for the PbPc crystal under high hydrostatic pressure by using a diamond anvil cell. The IR spectrum of PbPc shows three strong peaks in the 1000-1200 cm -1 region. With increasing pressure, the intensity ratio of the middle peak to the other two peaks increased. This result suggests a structural transformation of the PbPc molecule from the shuttle-cock structure toward the planar structure with increasing pressure. In the UV-visible spectra, two remarkable changes were observed under high pressure: the peak intensity of the band at 2.7 eV was decreased, and the band at 1.5 eV was shifted to lower energy and broadened. The former feature suggests that the highest occupied molecular orbital (HOMO) band is not filled perfectly in the solid-state of PbPc under ambient pressure, and that the filling of the HOMO band occurs with increasing pressure. The change on the low energy band at 1.5 eV due to increasing pressure can be attributed to an increase in the intermolecular interaction.

  12. An experimental study of the structural and vibrational properties of sesquiterpene lactone cnicin using FT-IR, FT-Raman, UV-visible and NMR spectroscopies

    NASA Astrophysics Data System (ADS)

    Chain, Fernando; Romano, Elida; Leyton, Patricio; Paipa, Carolina; Catalán, César Atilio Nazareno; Fortuna, Mario Antonio; Brandán, Silvia Antonia

    2014-05-01

    An experimental and theoretical investigation of cnicin is presented, combining the use of infrared, Raman, NMR and UV-visible spectroscopies with density functional theory (DFT) that employs hybrid B3LYP exchange correlation functional and a 6-31G? basis set. The molecular electrostatic potentials, atomic charges, bond orders, stabilization energies, topological properties and energy gap are presented by performing NBO, AIM and HOMO-LUMO calculations at the same level of theory as cnicin. A complete vibrational compound assignment was performed by employing internal coordinate analysis and a scaled quantum mechanical force field (SQMFF) methodology. Comparisons between the theoretical and experimental vibrational and ultraviolet-visible spectra show a strong concordance. The geometrical parameters and NBO studies suggest a probable negative Cotton effect for cnicin, which can be attributed to the ? ? ?? transition for an ?,?-unsaturated ?-lactone, as reported in the literature.

  13. Analytical Characterization of Fermentation Inhibitors in Biomass Pretreatment Samples Using Liquid Chromatography, UV-Visible Spectroscopy, and Tandem Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Sharma, Lekh N.; Becker, Christopher; Chambliss, C. Kevin

    A variety of chemicals are produced upon pretreatment of lignocellulosic biomass. Aliphatic acids, aromatic acids, aldehydes, and phenolic compounds are of particular interest due to their presumed inhibitory influence on downstream enzymatic or microbial steps in biomass-to-ethanol conversion. Herein, we describe a series of analytical protocols that collectively enable quantitative monitoring of 40 potential fermentation inhibitors in biomass pretreatment samples. Solid samples are accommodated by first employing pressurized fluid extraction to generate an aqueous “wash stream.” Sample preparation for liquids involves an initial precipitation-filtration step, followed by liquid-liquid extraction and reconstitution of extracts in water. Samples are analyzed using high-performance liquid chromatography (HPLC) in combination with ultraviolet (UV) absorbance and tandem mass spectrometry (MS/MS) detection. A standard addition approach is utilized for quantitation to alleviate complications arising from co-extracted sample matrix.

  14. [Raman spectroscopy applied to analytical quality control of injectable drugs: analytical evaluation and comparative economic versus HPLC and UV / visible-FTIR].

    PubMed

    Bourget, P; Amin, A; Vidal, F; Merlette, C; Troude, P; Corriol, O

    2013-09-01

    In France, central IV admixture of chemotherapy (CT) treatments at the hospital is now required by law. We have previously shown that the shaping of Therapeutic Objects (TOs) could profit from an Analytical Quality Assurance (AQA), closely linked to the batch release, for the three key parameters: identity, purity, and initial concentration of the compound of interest. In the course of recent and diversified works, we showed the technical superiority of non-intrusive Raman Spectroscopy (RS) vs. any other analytical option and, especially for both HPLC and vibrational method using a UV/visible-FTIR coupling. An interconnected qualitative and economic assessment strongly helps to enrich these relevant works. The study compares in operational situation, the performance of three analytical methods used for the AQC of TOs. We used: a) a set of evaluation criteria, b) the depreciation tables of the machinery, c) the cost of disposables, d) the weight of equipment and technical installations, e) the basic accounting unit (unit of work) and its composite costs (Euros), which vary according to the technical options, the weight of both human resources and disposables; finally, different combinations are described. So, the unit of work can take 12 different values between 1 and 5.5 Euros, and we provide various recommendations. A qualitative evaluation grid constantly places the SR technology as superior or equal to the 2 other techniques currently available. Our results demonstrated: a) the major interest of the non-intrusive AQC performed by RS, especially when it is not possible to analyze a TO with existing methods e.g. elastomeric portable pumps, and b) the high potential for this technique to be a strong contributor to the security of the medication circuit, and to fight the iatrogenic effects of drugs especially in the hospital. It also contributes to the protection of all actors in healthcare and of their working environment. PMID:24804411

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

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

    PubMed

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

    2015-03-01

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

  17. Optical constants and band gap determination of Pb0.95La0.05Zr0.54Ti0.46O3 thin films using spectroscopic ellipsometry and UV-visible spectroscopy

    NASA Astrophysics Data System (ADS)

    Batra, Vaishali; Kotru, Sushma; Varagas, M.; Ramana, C. V.

    2015-11-01

    We report the structural evolution and optical properties of lanthanum doped lead zirconate titanate (PLZT) thin films prepared on Pt/TiO2/SiO2/Si substrates by chemical solution deposition. X-ray diffraction demonstrates the post-deposition annealing induced crystallization for PLZT films annealed in a temperature (Ta) range of 550-750 °C. PLZT films annealed at higher temperature exhibit polycrystalline structure along with larger grain size. Optical band gap (Eg) values determined from UV-visible spectroscopy and spectroscopic ellipsometry (SE) for PLZT films were found to be in the range of 3.5-3.8 eV. Eg decreases with increasing Ta. The optical constants and their dispersion profiles for PLZT films were also determined from SE analyses. PLZT films show an index of refraction in the range of 2.46-2.50 (? = 632.8 nm) with increase in Ta. The increase in refractive index at higher Ta is attributed to the improved packing density and crystallinity with the temperature.

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

    PubMed Central

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

    2014-01-01

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

  19. UV/Visible Telescope with Hubble Disposal

    NASA Technical Reports Server (NTRS)

    Benford, Dominic J.

    2013-01-01

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

  20. Quantitative enantioselective Raman spectroscopy.

    PubMed

    Kiefer, J

    2015-08-01

    Analytical methods for quantitative enantioselective measurements are highly desirable in the life sciences. Existing technologies have disadvantages such as limited temporal resolution, the need for molecular labeling, or high experimental complexity. To overcome these limitations, this work presents a method based on conventional Raman spectroscopy. A systematic investigation of the key parameters is carried out. It is demonstrated that their careful choice provides an opportunity for enantioselective and quantitative analysis of enantiopure systems as well as enantiomer mixtures. PMID:26066374

  1. Quantitative spectroscopy of Deneb

    E-print Network

    Schiller, Florian

    2006-01-01

    Quantitative spectroscopy of luminous BA-type supergiants offers a high potential for modern astrophysics. The degree to which we can rely on quantitative studies of this class of stars as a whole depends on the quality of the analyses for benchmark objects. We constrain the basic atmospheric parameters and fundamental stellar parameters as well as chemical abundances of the prototype A-type supergiant Deneb to unprecedented accuracy (Teff = 8525 +/- 75 K, log(g) = 1.10 +/- 0.05 dex, M_spec = 19 +/- 3 M_sun, L = 1.96 +/- 0.32 *10^5 L_sun, R = 203 +/- 17 R_sun, enrichment with CN-processed matter) by applying a sophisticated hybrid NLTE spectrum synthesis technique which has recently been developed and tested. The study is based on a high-resolution and high-S/N spectrum obtained with the Echelle spectrograph FOCES on the Calar Alto 2.2m telescope. Practically all inconsistencies reported in earlier studies are resolved. Multiple metal ionization equilibria and numerous hydrogen lines from the Balmer, Paschen,...

  2. Quantitative spectroscopy of Deneb

    E-print Network

    Florian Schiller; Norbert Przybilla

    2007-12-01

    Quantitative spectroscopy of luminous BA-type supergiants offers a high potential for modern astrophysics. The degree to which we can rely on quantitative studies of this class of stars as a whole depends on the quality of the analyses for benchmark objects. We constrain the basic atmospheric parameters and fundamental stellar parameters as well as chemical abundances of the prototype A-type supergiant Deneb to unprecedented accuracy (Teff = 8525 +/- 75 K, log(g) = 1.10 +/- 0.05 dex, M_spec = 19 +/- 3 M_sun, L = 1.96 +/- 0.32 *10^5 L_sun, R = 203 +/- 17 R_sun, enrichment with CN-processed matter) by applying a sophisticated hybrid NLTE spectrum synthesis technique which has recently been developed and tested. The study is based on a high-resolution and high-S/N spectrum obtained with the Echelle spectrograph FOCES on the Calar Alto 2.2m telescope. Practically all inconsistencies reported in earlier studies are resolved. Multiple metal ionization equilibria and numerous hydrogen lines from the Balmer, Paschen, Brackett and Pfund series are brought into match simultaneously for the stellar parameter determination. Stellar wind properties are derived from H_alpha line-profile fitting using line-blanketed hydrodynamic non-LTE models. A self-consistent view of Deneb is thus obtained, allowing us to discuss its evolutionary state in detail by comparison with the most recent generation of evolution models for massive stars. (abridged)

  3. Simultaneous infrared and UV-visible absorption spectra of matrix-isolated carbon vapor

    NASA Technical Reports Server (NTRS)

    Kurtz, Joe; Huffman, Donald R.

    1989-01-01

    Carbon molecules were suggested as possible carriers of the diffuse interstellar bands. In particular, it was proposed that the 443 nm diffuse interstellar band is due to the same molecule which gives rise to the 447 nm absorption feature in argon matrix-isolated carbon vapor. If so, then an associated C-C stretching mode should be seen in the IR. By doing spectroscopy in both the IR and UV-visible regions on the same sample, the present work provides evidence for correlating UV-visible absorption features with those found in the IR. Early data indicates no correlation between the strongest IR feature (1997/cm) and the 447 nm band. Correlation with weaker IR features is being investigated.

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

    SciTech Connect

    Czerwinski, Kenneth

    2013-09-13

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

  5. Quantitative spectroscopy of Deneb

    NASA Astrophysics Data System (ADS)

    Schiller, F.; Przybilla, N.

    2008-03-01

    Context: Quantitative spectroscopy of luminous BA-type supergiants offers a high potential for modern astrophysics. Detailed studies allow the evolution of massive stars, galactochemical evolution, and the cosmic distance scale to be constrained observationally. Aims: A detailed and comprehensive understanding of the atmospheres of BA-type supergiants is required in order to use this potential properly. The degree to which we can rely on quantitative studies of this class of stars as a whole depends on the quality of the analyses for benchmark objects. We constrain the basic atmospheric parameters and fundamental stellar parameters, as well as chemical abundances of the prototype A-type supergiant Deneb to unprecedented accuracy by applying a sophisticated analysis methodology, which has recently been developed and tested. Methods: The analysis is based on high-S/N and high-resolution spectra in the visual and near-IR. Stellar parameters and abundances for numerous astrophysically interesting elements are derived from synthesis of the photospheric spectrum using a hybrid non-LTE technique, i.e. line-blanketed LTE model atmospheres and non-LTE line formation. Multiple metal ionisation equilibria and numerous hydrogen lines from the Balmer, Paschen, Brackett, and Pfund series are utilised simultaneously for the stellar parameter determination. The stellar wind properties are derived from H? line-profile fitting using line-blanketed hydrodynamic non-LTE models. Further constraints come from matching the photospheric spectral energy distribution from the UV to the near-IR L band. Results: The atmospheric parameters of Deneb are tightly constrained: effective temperature T_eff = 8525±75 K, surface gravity log g = 1.10±0.05, microturbulence ? = 8±1 km s-1, macroturbulence, and projected rotational velocity v sin i are both 20 ± 2 km s-1. The abundance analysis gives helium enrichment by 0.10 dex relative to solar and an N/C ratio of 4.44 ± 0.84 (mass fraction), implying strong mixing with CN-processed matter. The heavier elements are consistently underabundant by 0.20 dex compared to solar. Peculiar abundance patterns, which were suggested in previous analyses cannot be confirmed. Accounting for non-LTE effects is essential for removing systematic trends in the abundance determination, for minimising statistical 1?-uncertainties to ?10-20% and for establishing all ionisation equilibria at the same time. Conclusions: A luminosity of (1.96 ± 0.32)×105 L?, a radius of 203 ± 17 R_?, and a current mass of 19 ± 4 M? are derived. Comparison with stellar evolution predictions suggests that Deneb started as a fast-rotating late O-type star with M^ZAMS? 23 M_? on the main sequence and is currently evolving to the red supergiant stage. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofisica de Andalucia (CSIC). Appendix A is only available in electronic form at http://www.aanda.org

  6. A Quantitative Infrared Spectroscopy Experiment.

    ERIC Educational Resources Information Center

    Krahling, Mark D.; Eliason, Robert

    1985-01-01

    Although infrared spectroscopy is used primarily for qualitative identifications, it is possible to use it as a quantitative tool as well. The use of a standard curve to determine percent methanol in a 2,2,2-trifluoroethanol sample is described. Background information, experimental procedures, and results obtained are provided. (JN)

  7. Quantitative Spectroscopy of Deneb

    NASA Astrophysics Data System (ADS)

    Schiller, Florian; Przybilla, N.

    We use the visually brightest A-type supergiant Deneb (A2 Ia) as benchmark for testing a spectro- scopic analysis technique developed for quantitative studies of BA-type supergiants. Our NLTE spectrum synthesis technique allows us to derive stellar parameters and elemental abundances with unprecedented accuracy. The study is based on a high-resolution and high-S/N spectrum obtained with the Echelle spectrograph FOCES on the Calar Alto 2.2 m telescope. Practically all inconsistencies reported in earlier studies are resolved. A self-consistent view of Deneb is thus obtained, allowing us to discuss its evolutionary state in detail by comparison with the most recent generation of evolution models for massive stars. The basic atmospheric parameters Teff = 8525 ± 75 K and log g = 1.10 ± 0.05 dex (cgs) and the distance imply the following fundamental parameters for Deneb: M spec = 17 ± 3 M? , L = 1.77 ± 0.29 · 105 L? and R = 192 ± 16 R? . The derived He and CNO abundances indicate mixing with nuclear processed matter. The high N/C ratio of 4.64 ± 1.39 and a N/O ratio of 0.88 ± 0.07 (mass fractions) could in principle be explained by evolutionary models with initially very rapid rotation. A mass of ˜ 22 M? is implied for the progenitor on the zero-age main se- quence, i.e. it was a late O-type star. Significant mass-loss has occurred, probably enhanced by pronounced centrifugal forces. The observational constraints favour a scenario for the evolu- tion of Deneb where the effects of rotational mixing may be amplified by an interaction with a magnetic field. Analogous analyses of such highly luminous BA-type supergiants will allow for precision studies of different galaxies in the Local Group and beyond.

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

    SciTech Connect

    Ken Czerwinski; Phil Weck; Frederic Poineau

    2010-12-29

    Ultraviolet-Visible Spectroscopy (UV-Visible) and Time Resolved Laser Fluorescence Spectroscopy (TRLFS) optical techniques can permit on-line, real-time analysis of the actinide elements in a solvent extraction process. UV-Visible and TRLFS techniques have been used for measuring the speciation and concentration of the actinides under laboratory conditions. These methods are easily adaptable to multiple sampling geometries, such as dip probes, fiber-optic sample cells, and flow-through cell geometries. To fully exploit these techniques for GNEP applications, the fundamental speciation of the target actinides and the resulting influence on 3 spectroscopic properties must be determined. Through this effort detection limits, process conditions, and speciation of key actinide components can be establish and utilized in a range of areas of interest to GNEP, especially in areas related to materials accountability and process control.

  9. UV/visible camera for the Clementine mission

    SciTech Connect

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

    1995-04-01

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

  10. UV / Visible / Near-Infrared Reflectance Models for the Rapid and Non-Destructive Prediction and Classification of Cotton Color and Physical Indices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High volume instrumentation (HVI), utilized in the cotton industry to determine the qualities and classifications of cotton fibers, is time consuming, and prone to day-to-day and location-to-location variations. UV / visible / NIR spectroscopy, a rapid and easy sampling technique, was investigated a...

  11. QUANTITATIVE 15N NMR SPECTROSCOPY

    EPA Science Inventory

    Line intensities in 15N NMR spectra are strongly influenced by spin-lattice and spin-spin relaxation times, relaxation mechanisms and experimental conditions. Special care has to be taken in using 15N spectra for quantitative purposes. Quantitative aspects are discussed for the 1...

  12. Quantitative tunneling spectroscopy of nanocrystals

    SciTech Connect

    First, Phillip N; Whetten, Robert L; Schaaff, T Gregory

    2007-05-25

    The proposed goals of this collaborative work were to systematically characterize the electronic structure and dynamics of 3-dimensional metal and semiconducting nanocrystals using scanning tunneling microscopy/spectroscopy (STM/STS) and ballistic electron emission spectroscopy (BEES). This report describes progress in the spectroscopic work and in the development of methods for creating and characterizing gold nanocrystals. During the grant period, substantial effort also was devoted to the development of epitaxial graphene (EG), a very promising materials system with outstanding potential for nanometer-scale ballistic and coherent devices ("graphene" refers to one atomic layer of graphitic, sp2 -bonded carbon atoms [or more loosely, few layers]). Funding from this DOE grant was critical for the initial development of epitaxial graphene for nanoelectronics

  13. Non-contact quantitative diffuse reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Sorgato, Veronica; Berger, Michel; Emain, Charlotte; Koenig, Anne; Roig, Blandine; Vever-Bizet, Christine; Dinten, Jean-Marc; Bourg-Heckly, Geneviève; Planat-Chrétien, Anne

    2015-07-01

    We validate a non-contact Diffuse Reflectance Spectroscopy (DRS) system as a first stage to approach quantitative multi-spectral imaging technique. The non-contact DRS system with separated illumination and detection paths was developed with different progressive set-ups which were all compared to a well-founded contact DRS system. While quantitation of the absorption coefficient is well achieved with the existing method, the calculation of the scattering coefficient is deteriorated by the non-contact architecture measurements. We have therefore developed an adaptive reference-based algorithm to compensate for this effect.

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

    NASA Technical Reports Server (NTRS)

    Roscoe, Howard K.; Freshwater, Ray A.; Jones, Rod L.; Fish, Debbie J.; Harries, John E.; Wolfenden, Roger; Stone, Phillip

    1994-01-01

    We have constructed a novel instrument for ground-based remote sensing, by mounting a UV-visible spectrometer on a telescope and observing the absorption by atmospheric constituents of light from stars. Potentially, the instrument can observe stratospheric O3, NO3, NO2, and OClO.

  15. Differentiating sources of soil water soluble organic matter by UV-visible spectral models

    Technology Transfer Automated Retrieval System (TEKTRAN)

    UV-visible spectral models have been used to differentiate sources of dissolved organic matter in sea/fresh waters. Little information is available on using these models to characterize soil soluble organic matter. The objective of this study was to determine sources of soil soluble organic matter b...

  16. OPTICAL DESIGN AND PERFORMANCE OF THE ODIN UV/VISIBLE SPECTROGRAPH AND INFRARED IMAGER INSTRUMENT

    E-print Network

    Saskatchewan, University of

    OPTICAL DESIGN AND PERFORMANCE OF THE ODIN UV/VISIBLE SPECTROGRAPH AND INFRARED IMAGER INSTRUMENT is a high performance, lightweight (12 kilograms) ultraviolet/visible imaging spectrograph and infrared and Infra-Red Imaging System. Routes Incorporated is building this space science instrument for the Canadian

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  18. Theoretical investigation on bridged triarylamine helicenes: UV/visible and circular dichroism spectra

    NASA Astrophysics Data System (ADS)

    Spassova, Milena; Asselberghs, Inge; Verbiest, Thierry; Clays, Koen; Botek, Edith; Champagne, Benoît

    2007-05-01

    The UV/visible and CD spectra of bridged triarylamine helicenes have been simulated using the TDDFT/B3LYP/6-31+G(d) method. They reproduce well the experimental spectra. For M-helicenes, the Cotton effect associated with the lowest-energy transition is negative for the smallest helicenes and becomes positive for the largest one, as a result of the variations of the angle between the electric and magnetic transition dipole moments. Since these species are stable upon oxidation, the UV/visible and CD spectra of their radical cations have been simulated. They show low-energy absorption and CD bands, figuring out enhancement of the first hyperpolarizability.

  19. UV-visible light-activated Ag-decorated, monodisperse TiO2 aggregates for treatment of the pharmaceutical oxytetracycline.

    PubMed

    Han, Changseok; Likodimos, Vlassis; Khan, Javed Ali; Nadagouda, Mallikarjuna N; Andersen, Joel; Falaras, Polycarpos; Rosales-Lombardi, Pablo; Dionysiou, Dionysios D

    2014-10-01

    Noble metal Ag-decorated, monodisperse TiO2 aggregates were successfully synthesized by an ionic strength-assisted, simple sol-gel method and were used for the photocatalytic degradation of the antibiotic oxytetracycline (OTC) under both UV and visible light (UV-visible light) irradiation. The synthesized samples were characterized by X-ray diffraction analysis (XRD); UV-vis diffuse reflectance spectroscopy; environmental scanning electron microscopy (ESEM); transmission electron microscopy (TEM); high-resolution TEM (HR-TEM); micro-Raman, energy-dispersive X-ray spectroscopy (EDS); and inductively coupled plasma optical emission spectrometry (ICP-OES). The results showed that the uniformity of TiO2 aggregates was finely tuned by the sol-gel method, and Ag was well decorated on the monodisperse TiO2 aggregates. The absorption of the samples in the visible light region increased with increasing Ag loading that was proportional to the amount of Ag precursor added in the solution over the tested concentration range. The Brunauer, Emmett, and Teller (The BET) surface area slightly decreased with increasing Ag loading on the TiO2 aggregates. Ag-decorated TiO2 samples demonstrated enhanced photocatalytic activity for the degradation of OTC under UV-visible light illumination compared to that of pure TiO2. The sample containing 1.9 wt% Ag showed the highest photocatalytic activity for the degradation of OTC under both UV-visible light and visible light illumination. During the experiments, the detected Ag leaching for the best TiO2-Ag photocatalyst was much lower than the National Secondary Drinking Water Regulation for Ag limit (0.1 mg L(-1)) issued by the US Environmental Protection Agency. PMID:24217967

  20. Modeling the Effect of Polychromatic Light in Quantitative Absorbance Spectroscopy

    ERIC Educational Resources Information Center

    Smith, Rachel; Cantrell, Kevin

    2007-01-01

    Laboratory experiment is conducted to give the students practical experience with the principles of electronic absorbance spectroscopy. This straightforward approach creates a powerful tool for exploring many of the aspects of quantitative absorbance spectroscopy.

  1. The stability of aqueous nickel(II) chloride complexes in hydrothermal solutions: Results of UV-Visible spectroscopic experiments

    NASA Astrophysics Data System (ADS)

    Liu, Weihua; Migdisov, Artas; Williams-Jones, Anthony

    2012-10-01

    Knowledge of the thermodynamic properties of aqueous nickel chloride complexes is important for understanding and quantitatively evaluating nickel transport in hydrothermal systems. In this paper, UV-Visible spectroscopic measurements are reported for dissolved nickel in perchlorate, triflic acid and sodium chloride solutions at temperatures up to 250 °C and 100 bar. The observed molar absorbance of Ni2+ in both perchlorate and triflic acid solutions is similar, and the absorbance peak migrates toward lower energy (red-shift) with increasing temperature. The spectra of nickel chloride solutions show a systematic red-shift with increasing temperature and/or chloride concentration. This allowed identification of the nickel chloride species as NiCl+, NiCl2(aq) and NiCl3-, and determination of their formation constants. Based on the experimental data reported in this paper and those of previous experimental studies, formation constants for these nickel chloride complexes have been calculated for temperatures up to 700 °C and pressures up to 2000 bar. The solubility of millerite (NiS) and pentlandite (Ni4.5Fe4.5S8) calculated using these constants shows that nickel dissolves in significantly higher concentrations in hydrothermal solutions than previously estimated. However, the solubility is considerably lower than for corresponding cobalt sulphide minerals. This may explain why hydrothermal nickel deposits are encountered so much less frequently than hydrothermal deposits of cobalt.

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

    PubMed

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

    2014-10-15

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

  3. UV-visible transmittance of silicone-hydrogel contact lenses measured with a fiber optic spectrometer

    NASA Astrophysics Data System (ADS)

    Fuentes, R.; Fernández, E.; Pascual, I.; García, C.

    2013-11-01

    Protein deposition is one of the most frequent contaminants occurring on hydrophilic contact lenses and may modify the lens optical properties. The silicone-hydrogel contact lenses usually adsorb a lower amount of proteins than the conventional hydrogel ones. However it is important to study the influence of protein deposits on some silicone-hydrogel contact lenses properties, such as UV-Visible transmittance. In this study it is measured de UV-Visible properties of new and worn silicone-hydrogel contact lenses and the transmittance changes that can occur with wear are quantified. An optical fiber spectrometer has been used for measuring the transmittance of contact lenses. This spectrometer has the advantage that the lens can be positioned horizontally and the light beam passes through it perpendicularly. For the measurements, it was necessary to make a special cuvette to put inside the lens and keep it submerged in sterile saline solution. The contact lenses used were Biofinity®. They are manufactured by CooperVision with a material whose technical name is Comfilcon A. This material has not yet been analyzed for this purpose. Moreover, in this type of studies are commonly taken lenses of power -3.00D, however we have not limited to a single power value but we have extended the range to lower and higher values regarding to the standard power in order to see how this parameter affects.

  4. Quantitative atomic spectroscopy for primary thermometry

    SciTech Connect

    Truong, Gar-Wing; Luiten, Andre N.; May, Eric F.; Stace, Thomas M.

    2011-03-15

    Quantitative spectroscopy has been used to measure accurately the Doppler broadening of atomic transitions in {sup 85}Rb vapor. By using a conventional platinum resistance thermometer and the Doppler thermometry technique, we were able to determine k{sub B} with a relative uncertainty of 4.1x10{sup -4} and with a deviation of 2.7x10{sup -4} from the expected value. Our experiment, using an effusive vapor, departs significantly from other Doppler-broadened thermometry (DBT) techniques, which rely on weakly absorbing molecules in a diffusive regime. In these circumstances, very different systematic effects such as magnetic sensitivity and optical pumping are dominant. Using the model developed recently by Stace and Luiten, we estimate the perturbation due to optical pumping of the measured k{sub B} value was less than 4x10{sup -6}. The effects of optical pumping on atomic and molecular DBT experiments is mapped over a wide range of beam size and saturation intensity, indicating possible avenues for improvement. We also compare the line-broadening mechanisms, windows of operation and detection limits of some recent DBT experiments.

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

    NASA Astrophysics Data System (ADS)

    Sension, Roseanne

    2015-03-01

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

  6. Validation of GOMOS vertical profiles using the stratospheric balloon-borne AMON and SALOMON UV-visible spetrometers

    NASA Astrophysics Data System (ADS)

    Renard, J.-B.; Chartier, M.; Berthet, G.; Robert, C.; Lemaire, T.; Pepe, F.; George, M.; Pirre, M.

    2003-08-01

    The stratospheric balloon-borne UV-visible spectrometers AMON and SALOMON, which use stars and Moon as light source, respectively, are involved in the validation of the UV-visible spectrometer GOMOS onboard ENVISAT, which uses also stars as light source. A low spectral resolution UV-visible spectrometer, AMON-RA, is also implanted in the AMON gondola, for the analysis of the chromatic scintillation effect. A flight of SALOMON occurred in September 19, 2002, at mid latitude from Aire sur l'Adour, France. An AMON (and AMON-RA) flight occurred at high latitude from Kiruna (northern Sweden) on March 1, 2003. The vertical profiles are compared to those obtained by GOMOS. Taking into account the effect of the chromatic scintillation on the transmission spectra, recommendations will be proposed in order to improve the GOMOS retrievals.

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

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  8. INTERACTIONS OF METHYL ORANGE WITH CYCLODEXTRIN/SODIUM-MONTMORILLONITE SYSTEMS PROBED BY UV-VISIBLE SPECTROSCOPY

    EPA Science Inventory

    Clay mineral colloids play important roles in the adsorption of polar organic contaminants in the environment. Similarly, cyclodextrins (CD) can entrap poorly water-soluble organic compounds. A combination of CDs and clay minerals affords great opportunities to investigate simult...

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

    ERIC Educational Resources Information Center

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

    2014-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  12. PSC and volcanic aerosol routine observations in Antarctica by UV-visible ground-based spectrometry

    NASA Technical Reports Server (NTRS)

    Sarkissian, A.; Pommereau, J. P.; Goutail, F.

    1994-01-01

    Polar statospheric clouds (PSC) and stratospheric aerosol can be observed by ground-based UV-visible spectrometry by looking at the variation of the color of the sky during twilight. A radiative transfer model shows that reddenings are caused by high altitude (22-28 km) thin layers of scatterers, while low altitude (12-20 km) thick ones result in blueings. The color index method applied on 4 years of observations at Dumont d'Urville (67 deg S), from 1988 to 1991, shows that probably because the station is located at the edge of the vortex, dense PSC are uncommon. More unexpected is the existence of a systematic seasonal variation of the color of the twilight sky - bluer at spring - which reveals the formation of a dense scattering layer at or just above the tropopause at the end of the winter. Large scattering layers are reported above the station in 1991, first in August around 12-14 km, later in September at 22-24 km. They are attributed to volcanic aerosol from Mt Hudson and Mt Pinatubo respectively, which erupted in 1991. Inspection of the data shows that the lowest entered rapidly into the polar vortex but not the highest which remained outside, demonstrating that the vortex was isolated at 22-26 km.

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

    NASA Technical Reports Server (NTRS)

    Mitchell, B. Greg

    2000-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  15. Compressed Cu[sup 2+] ions in a Bi[sub 4]V[sub 2]O[sub 11] oxide matrix. 1. EPR and UV-visible study

    SciTech Connect

    Aboukais, A.; Delmaire, F.; Rigole, M.; Hubaut, R.; Mairesse, G.

    1993-12-01

    BICUVOX.x (Bi[sub 2]V[sub 1-x]Cu[sub x]O[sub 5.5-1.5x]) prepared with different atomic ratios Cu/V and calcined under a dry air at 1093 K have been characterized by electron paramagnetic resonance (EPR). The inverted g anisotropy values of the copper(II) ions EPR signal (g[sub perpendicular] > g[sub parallel]) can be interpreted by an octahedral symmetry strongly distorted with a compression of oxygen atoms along the apical direction. These results have been confirmed by UV-visible spectroscopy. 29 refs., 4 figs., 1 tab.

  16. Intercomparison of total ozone data from nimbus 7 TOMS, the Brewer UV spectrophotometer and SOAZ uv-visible spectrophotometer at high latitudes observatory, Sodankylae

    SciTech Connect

    Kyroe, E.

    1993-04-09

    The use of visible spectroscopy makes it possible to measure stratospheric constituents when Solar Zenith Angle (SZA) is as large as 93[degree]. This fact allows the daily measurements of ozone and other species throughout the year at and beyond the latitudes of the polar circle. Because the visible spectroscopy is a new technique in ozone monitoring, it is useful to compare it with the classical uv spectroscopy. At Sodankylae the widely-used SAOZ uv/visible spectrophotometer (Systeme d'Analyse et d'Observations Zenithales) and the modern uv spectrophotometer Brewer have been measuring side by side since early 1990. This paper reports the first long-term intercomparison between the daily total ozone values measured by the SAOZ and the Brewer covering the period from February 1990 to June 1991. As a reference the intercomparison between the Brewer and TOMS (Total Ozone Mapping Spectrometer) instruments from May 1988 to December 1991 is also reported. 13 refs., 4 figs., 2 tabs.

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

    EPA Science Inventory

    Confocal Microscopy System Performance: QA tests, Quantitation and Spectroscopy.

    Robert M. Zucker 1 and Jeremy M. Lerner 2,
    1Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research Development, U.S. Environmen...

  18. PoS(NIC-IX)174 Quantitative Spectroscopy of Deneb

    E-print Network

    Przybilla, Norbert

    PoS(NIC-IX)174 Quantitative Spectroscopy of Deneb F. Schiller and N. Przybilla Dr. Remeis@sternwarte.uni-erlangen.de We use the visually brightest A-type supergiant Deneb (A2 Ia) as benchmark for testing a spectro studies are resolved. A self-consistent view of Deneb is thus obtained, allowing us to discuss its

  19. Quaternary Ammonium Oxidative Demethylation: X-ray Crystallographic, Resonance Raman and UV-visible Spectroscopic Analysis of a Rieske-type Demethylase

    SciTech Connect

    Daughtry K. D.; Orville A.; Xiao, Y.; Stoner-Ma, D.; Cho, E.; Liu, P.; Allen, K. N.

    2012-02-01

    Herein, the structure resulting from in situ turnover in a chemically challenging quaternary ammonium oxidative demethylation reaction was captured via crystallographic analysis and analyzed via single-crystal spectroscopy. Crystal structures were determined for the Rieske-type monooxygenase, stachydrine demethylase, in the unliganded state (at 1.6 {angstrom} resolution) and in the product complex (at 2.2 {angstrom} resolution). The ligand complex was obtained from enzyme aerobically cocrystallized with the substrate stachydrine (N,N-dimethylproline). The ligand electron density in the complex was interpreted as proline, generated within the active site at 100 K by the absorption of X-ray photon energy and two consecutive demethylation cycles. The oxidation state of the Rieske iron-sulfur cluster was characterized by UV-visible spectroscopy throughout X-ray data collection in conjunction with resonance Raman spectra collected before and after diffraction data. Shifts in the absorption band wavelength and intensity as a function of absorbed X-ray dose demonstrated that the Rieske center was reduced by solvated electrons generated by X-ray photons; the kinetics of the reduction process differed dramatically for the liganded complex compared to unliganded demethylase, which may correspond to the observed turnover in the crystal.

  20. Basic Principles of Spectroscopy

    NASA Astrophysics Data System (ADS)

    Penner, Michael H.

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

  1. Quantitative transmission Raman spectroscopy of pharmaceutical tablets and capsules.

    PubMed

    Johansson, Jonas; Sparén, Anders; Svensson, Olof; Folestad, Staffan; Claybourn, Mike

    2007-11-01

    Quantitative analysis of pharmaceutical formulations using the new approach of transmission Raman spectroscopy has been investigated. For comparison, measurements were also made in conventional backscatter mode. The experimental setup consisted of a Raman probe-based spectrometer with 785 nm excitation for measurements in backscatter mode. In transmission mode the same system was used to detect the Raman scattered light, while an external diode laser of the same type was used as excitation source. Quantitative partial least squares models were developed for both measurement modes. The results for tablets show that the prediction error for an independent test set was lower for the transmission measurements with a relative root mean square error of about 2.2% as compared with 2.9% for the backscatter mode. Furthermore, the models were simpler in the transmission case, for which only a single partial least squares (PLS) component was required to explain the variation. The main reason for the improvement using the transmission mode is a more representative sampling of the tablets compared with the backscatter mode. Capsules containing mixtures of pharmaceutical powders were also assessed by transmission only. The quantitative results for the capsules' contents were good, with a prediction error of 3.6% w/w for an independent test set. The advantage of transmission Raman over backscatter Raman spectroscopy has been demonstrated for quantitative analysis of pharmaceutical formulations, and the prospects for reliable, lean calibrations for pharmaceutical analysis is discussed. PMID:18028700

  2. Validation of GOMOS vertical profiles using the stratospheric balloon-borne AMON and SALOMON UV-Visible spectrometers

    NASA Astrophysics Data System (ADS)

    Renard, J. B.; Chartier, M.; Berthet, G.; Robert, C.; Lemaire, T.; Pepe, F.; George, M.; Pirre, M.

    2003-04-01

    The stratospheric balloon-borne UV-visible spectrometers AMON and SALOMON, which uses stars and Moon as light source, respectively, were involved in the validation of the UV-visible spectrometer GOMOS onboard ENVISAT, which uses also stars as light source. A low spectral resolution UV-visible spectrometer, AMON-RA, is also implanted in the AMON gondola, for the validation of the GOMOS algorithm dedicated to the correction of the chromatic scintillation effect. A flight of SALOMON occurred in September 19, 2002, at mid latitude from Aire sur l’Adour, France. The night-time SALOMON and GOMOS measurements were conducted at the same time (around 21h30 TU) and with a spatial coincidence less than 250 km. Comparison of vertical profiles was done for an altitude in the 15-40 km range. While the global shape of the GOMOS and SALOMON ozone profiles are quite in agreement, the GOMOS NO2 and NO3 profiles are unrealistic when compared to SALOMON profiles. A reanalysis of the GOMOS transmission using algorithms already developed for SALOMON shows that accurate NO2 and NO3 profiles can be retrieved if DOAS technique and dedicated spectral windows are used. An AMON (and AMON-RA) flight and a new SALOMON flight should occurred at high latitude from Kiruna (northern Sweden) in January and March 2003, respectively. The same analyses as for the September 2002 flight will be conducted, including this time the OClO and aerosols extinction coefficient retrievals. Taking into account the effect of the chromatic scintillation on the transmission spectra, recommendations will be proposed in order to improve the GOMOS retrievals.

  3. A nearly on-axis spectroscopic system for simultaneously measuring UV-visible absorption and X-ray diffraction in the SPring-8 structural genomics beamline.

    PubMed

    Sakaguchi, Miyuki; Kimura, Tetsunari; Nishida, Takuma; Tosha, Takehiko; Sugimoto, Hiroshi; Yamaguchi, Yoshihiro; Yanagisawa, Sachiko; Ueno, Go; Murakami, Hironori; Ago, Hideo; Yamamoto, Masaki; Ogura, Takashi; Shiro, Yoshitsugu; Kubo, Minoru

    2016-01-01

    UV-visible absorption spectroscopy is useful for probing the electronic and structural changes of protein active sites, and thus the on-line combination of X-ray diffraction and spectroscopic analysis is increasingly being applied. Herein, a novel absorption spectrometer was developed at SPring-8 BL26B2 with a nearly on-axis geometry between the X-ray and optical axes. A small prism mirror was placed near the X-ray beamstop to pass the light only 2° off the X-ray beam, enabling spectroscopic analysis of the X-ray-exposed volume of a crystal during X-ray diffraction data collection. The spectrometer was applied to NO reductase, a heme enzyme that catalyzes NO reduction to N2O. Radiation damage to the heme was monitored in real time during X-ray irradiation by evaluating the absorption spectral changes. Moreover, NO binding to the heme was probed via caged NO photolysis with UV light, demonstrating the extended capability of the spectrometer for intermediate analysis. PMID:26698082

  4. Quantitative polarized Raman spectroscopy in highly turbid bone tissue

    PubMed Central

    Raghavan, Mekhala; Sahar, Nadder D.; Wilson, Robert H.; Mycek, Mary-Ann; Pleshko, Nancy; Kohn, David H.; Morris, Michael D.

    2010-01-01

    Polarized Raman spectroscopy allows measurement of molecular orientation and composition and is widely used in the study of polymer systems. Here, we extend the technique to the extraction of quantitative orientation information from bone tissue, which is optically thick and highly turbid. We discuss multiple scattering effects in tissue and show that repeated measurements using a series of objectives of differing numerical apertures can be employed to assess the contributions of sample turbidity and depth of field on polarized Raman measurements. A high numerical aperture objective minimizes the systematic errors introduced by multiple scattering. We test and validate the use of polarized Raman spectroscopy using wild-type and genetically modified (oim?oim model of osteogenesis imperfecta) murine bones. Mineral orientation distribution functions show that mineral crystallites are not as well aligned (p<0.05) in oim?oim bones (28±3 deg) compared to wild-type bones (22±3 deg), in agreement with small-angle X-ray scattering results. In wild-type mice, backbone carbonyl orientation is 76±2 deg and in oim?oim mice, it is 72±4 deg (p>0.05). We provide evidence that simultaneous quantitative measurements of mineral and collagen orientations on intact bone specimens are possible using polarized Raman spectroscopy. PMID:20615030

  5. Optical spectroscopy for quantitative sensing in human pancreatic tissues

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

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

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

    SciTech Connect

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

    2008-11-01

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

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

    SciTech Connect

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

    1994-06-22

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

  8. Quantitative histochemical analysis of human artery using Raman spectroscopy.

    PubMed

    Manoharan, R; Baraga, J J; Feld, M S; Rava, R P

    1992-10-30

    We have developed a method for using near infrared Raman spectroscopy to quantitatively analyze the histochemical composition of human artery. The main contributors to bands observed in the Raman spectra of normal and atherosclerotic aorta are the proteins collagen and elastin, cholesterol lipids, and calcium hydroxyapatite. The Raman scattering cross-sections of different bands for these components have been determined in order to understand their relative contributions to the Raman spectra of biological tissue. The Raman signal is observed to behave linearly with the concentration of the components, even in a highly scattering medium such as a powder. Using these data, we have developed a linear model that can be used to extract the quantitative contribution of an individual component to the spectrum of a mixture. The model has been applied to several mixtures of known composition of tissue constituents in order to evaluate its precision and accuracy. The calculated fit coefficients from the spectra are in agreement with the measured values within experimental uncertainties. The spectra of different types of atherosclerotic aorta have also been modeled, and we have extracted quantitative information regarding the relative concentration of biological constituents in atherosclerotic aorta. PMID:1474427

  9. The Infrared and UV-Visible Spectra of Polycyclic Aromatic Hydrocarbons Containing (5, 7)-Member Ring Defects: A Theoretical Study

    NASA Astrophysics Data System (ADS)

    Yu, Hua-Gen; Nyman, Gunnar

    2012-05-01

    We report a theoretical investigation of the infrared (IR) spectra of polycyclic aromatic hydrocarbons (PAHs) containing (5, 7)-member ring defects based on a C48H18 model. Calculations are mostly performed using the hybrid B3LYP density functional theory (DFT) with a 6-31G(d) or 4-31G basis set. The results show that the Stone-Wales defect in PAHs can yield a strong IR band at 1448 cm-1 and a weak band at 611 cm-1, which may contribute to the UIR (unidentified infrared) bands at 6.9 ?m and 16.4 ?m observed in the interstellar medium. The charge effect on the IR spectra is discussed. The stability of the ring defected PAHs is also addressed by exploring the minimum energy pathway on the potential energy surface and through their UV-visible spectra, which are computed using a TDDFT method.

  10. SALOMON: A New, Light Balloonborne UV visible spectrometer for Nighttime Observations of Stratospheric Trace-Gas Species

    NASA Astrophysics Data System (ADS)

    Renard, Jean-Baptiste; Chartier, Michel; Robert, Claude; Chalumeau, Gilles; Berthet, Gwenaël; Pirre, Michel; Pommereau, Jean-Pierre; Goutail, Florence

    2000-01-01

    A new, light balloonborne UV visible spectrometer, called SALOMON, is designed to perform nighttime measurements of stratospheric trace-gas species by using the Moon as a light source. The first flight, performed on 31 October 1998 at mid-latitude with a float altitude of 26.7 km, allowed the performance of the pointing system to be checked and vertical profiles of ozone, NO 2 , NO 3 , and possibly OBrO to be obtained. First the instrument and then the performance of the pointing system and the detector are described. Finally the vertical profiles are compared with other profiles obtained at the same location five years before with the heavier balloonborne spectrometer AMON, which uses a star as the light source.

  11. UV-Visible and Plasmonic Nanospectroscopy of the CO2 Adsorption Energetics in a Microporous Polymer.

    PubMed

    Nugroho, Ferry A A; Xu, Chao; Hedin, Niklas; Langhammer, Christoph

    2015-10-20

    In the context of carbon capture and storage (CCS), micro- and mesoporous polymers have received significant attention due to their ability to selectively adsorb and separate CO2 from gas streams. The performance of such materials is critically dependent on the isosteric heat of adsorption (Qst) of CO2 directly related to the interaction strength between CO2 and the adsorbent. Here, we show using the microporous polymer PIM-1 as a model system that its Qst can be conveniently determined by in situ UV-vis optical transmission spectroscopy directly applied on the adsorbent or, with higher resolution, by indirect nanoplasmonic sensing based on localized surface plasmon resonance in metal nanoparticles. Taken all together, this study provides a general blueprint for efficient optical screening of micro- and mesoporous polymeric materials for CCS in terms of their CO2 adsorption energetics and kinetics. PMID:26413906

  12. Quantitative investigation of two metallohydrolases by X-ray absorption spectroscopy near-edge spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhao, W.; Chu, W. S.; Yang, F. F.; Yu, M. J.; Chen, D. L.; Guo, X. Y.; Zhou, D. W.; Shi, N.; Marcelli, A.; Niu, L. W.; Teng, M. K.; Gong, W. M.; Benfatto, M.; Wu, Z. Y.

    2007-09-01

    The last several years have witnessed a tremendous increase in biological applications using X-ray absorption spectroscopy (BioXAS), thanks to continuous advancements in synchrotron radiation (SR) sources and detector technology. However, XAS applications in many biological systems have been limited by the intrinsic limitations of the Extended X-ray Absorption Fine Structure (EXAFS) technique e.g., the lack of sensitivity to bond angles. As a consequence, the application of the X-ray absorption near-edge structure (XANES) spectroscopy changed this scenario that is now continuously changing with the introduction of the first quantitative XANES packages such as Minut XANES (MXAN). Here we present and discuss the XANES code MXAN, a novel XANES-fitting package that allows a quantitative analysis of experimental data applied to Zn K-edge spectra of two metalloproteins: Leptospira interrogans Peptide deformylase ( LiPDF) and acutolysin-C, a representative of snake venom metalloproteinases (SVMPs) from Agkistrodon acutus venom. The analysis on these two metallohydrolases reveals that proteolytic activities are correlated to subtle conformation changes around the zinc ion. In particular, this quantitative study clarifies the occurrence of the LiPDF catalytic mechanism via a two-water-molecules model, whereas in the acutolysin-C we have observed a different proteolytic activity correlated to structural changes around the zinc ion induced by pH variations.

  13. A Method for Quantitative Mapping of Thick Oil Spills Using Imaging Spectroscopy

    E-print Network

    A Method for Quantitative Mapping of Thick Oil Spills Using Imaging Spectroscopy By Roger N. Clark (AVIRIS) Team, 2010, A method for quantitative mapping of thick oil spills using imaging spectroscopy: U ....................................................................................................................................................14 Figures 1. Image of oil emulsion from the Deepwater Horizon oil spill in the Gulf of Mexico off

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

    NASA Astrophysics Data System (ADS)

    Purcell, Dale Kevin

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

  15. UV-visible scanning spectrophotometry and chemometric analysis as tools for carotenoids analysis in cassava genotypes (Manihot esculenta Crantz).

    PubMed

    Moresco, Rodolfo; Uarrota, Virgílio Gavicho; Pereira, Aline; Tomazzoli, Maíra Maciel; Nunes, Eduardo da C; Peruch, Luiz Augusto Martins; Gazzola, Jussara; Costa, Christopher; Rocha, Miguel; Maraschin, Marcelo

    2015-01-01

    In this study, the metabolomics characterization focusing on the carotenoid composition of ten cassava (Manihot esculenta) genotypes cultivated in southern Brazil by UV-visible scanning spectrophotometry and reverse phase-high performance liquid chromatography was performed. Cassava roots rich in ?-carotene are an important staple food for populations with risk of vitamin A deficiency. Cassava genotypes with high pro-vitamin A activity have been identified as a strategy to reduce the prevalence of deficiency of this vitamin. The data set was used for the construction of a descriptive model by chemometric analysis. The genotypes of yellow-fleshed roots were clustered by the higher concentrations of cis-?-carotene and lutein. Inversely, cream-fleshed roots genotypes were grouped precisely due to their lower concentrations of these pigments, as samples rich in lycopene (redfleshed) differed among the studied genotypes. The analytical approach (UV-Vis, HPLC, and chemometrics) used showed to be efficient for understanding the chemodiversity of cassava genotypes, allowing to classify them according to important features for human health and nutrition. PMID:26673931

  16. THE INFRARED AND UV-VISIBLE SPECTRA OF POLYCYCLIC AROMATIC HYDROCARBONS CONTAINING (5, 7)-MEMBER RING DEFECTS: A THEORETICAL STUDY

    SciTech Connect

    Yu Huagen; Nyman, Gunnar E-mail: nyman@chem.gu.se

    2012-05-20

    We report a theoretical investigation of the infrared (IR) spectra of polycyclic aromatic hydrocarbons (PAHs) containing (5, 7)-member ring defects based on a C{sub 48}H{sub 18} model. Calculations are mostly performed using the hybrid B3LYP density functional theory (DFT) with a 6-31G(d) or 4-31G basis set. The results show that the Stone-Wales defect in PAHs can yield a strong IR band at 1448 cm{sup -1} and a weak band at 611 cm{sup -1}, which may contribute to the UIR (unidentified infrared) bands at 6.9 {mu}m and 16.4 {mu}m observed in the interstellar medium. The charge effect on the IR spectra is discussed. The stability of the ring defected PAHs is also addressed by exploring the minimum energy pathway on the potential energy surface and through their UV-visible spectra, which are computed using a TDDFT method.

  17. Silver nanoparticles coated with natural polysaccharides as models to study AgNP aggregation kinetics using UV-Visible spectrophotometry upon discharge in complex environments.

    PubMed

    Lodeiro, Pablo; Achterberg, Eric P; Pampín, Joaquín; Affatati, Alice; El-Shahawi, Mohammed S

    2016-01-01

    This study provides quantitative information on the aggregation and dissolution behaviour of silver nanoparticles (AgNPs) upon discharge in fresh and sea waters, represented here as NaCl solutions of increasing ionic strength (up to 1M) and natural fjord waters. Natural polysaccharides, sodium alginate (ALG) and gum Arabic (GA), were used as coatings to stabilize the AgNPs and the compounds acted as models to study AgNP aggregation kinetics. The DLVO theory was used to quantitatively describe the interactions between the AgNPs. The stability of AgNPs was established using UV-Visible spectrophotometry, including unique information collected during the first seconds of the aggregaton process. Alginate coating resulted in a moderate stabilization of AgNPs in terms of critical coagulation concentration (~82mM NaCl) and a low dissolution of <10% total Ag in NaCl solutions up to 1M. Gum Arabic coated AgNPs were more strongly stabilized, with ~7-30% size increase up to 77mM NaCl, but only when the silver ion content initially present in solution was low (<10% total Ag). The ALG and GA coated AgNPs showed a strongly enhanced stability in natural fjord waters (ca. 5h required to reduce the area of the surface plasmon resonance band (SPRB) by two fold) compared with NaCl at an equivalent ionic strength (1-2min period for a two fold SPRB reduction). This is ascribed to a stabilizing effect from dissolved organic matter present in natural fjord waters. Interestingly, for AgNP-GA solutions with 40% of total silver present as unreacted silver ions in the NP stock solution, fast aggregation kinetics were observed in NaCl solutions (SPRB area was reduced by ca. 50% within 40-150min), with even more rapid removal in fjord waters, attributed to the high amount of silver-chloride charged species, that interact with the NP coating and/or organic matter and reduce the NPs stabilization. PMID:26363390

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    Organic-inorganic hybrid photo-detectors with a self-sufficient mode of operation represent a research area of great current interest. In most efficient photodetectors and optoelectronic devices compound semiconductors containing toxic elements such as Cd, As, Te, S, Se etc. are used and these are also expensive. Hence there is also a rapidly growing interest in replacing these with environmentally friendly and earth-abundant materials. Herein, we report a facile solution-processed fabrication of a self-powered organic-inorganic hybrid photodetector using n-type oriented ZnO nanorods and p-type Spiro-MeOTAD semiconductor. ZnO is eco-friendly and earth-abundant, and Spiro-MeOTAD is non-hazardous. We show that the latter has far less toxicity than the toxic elements stated above. This visible blind UV photodetector shows high sensitivity (102) and a UV/visible rejection ratio of 300. It also exhibits fast response times of ?rise ~ 200 ?s and ?fall ~ 950 ?s. Importantly, with a small modification of nitrogen incorporation in ZnO one can also realize a highly-sensitive self-powered visible light photodetector with at least 1000% (or higher) improvements in quality factors (photocurrent/sensitivity/response time) as compared to previously reported organic-inorganic hybrid photo-detectors based on metal-chalcogenides (CdS-PANI or CuInSe2-P3HT). Interestingly, the broadband sensitivity of such N:ZnO-Spiro-MeOTAD photodiode enables sensing of low intensity (~28 ?W cm-2) ambient white light with a high photocurrent density of 120 nA cm-2 making it an efficient ambient white light detector.Organic-inorganic hybrid photo-detectors with a self-sufficient mode of operation represent a research area of great current interest. In most efficient photodetectors and optoelectronic devices compound semiconductors containing toxic elements such as Cd, As, Te, S, Se etc. are used and these are also expensive. Hence there is also a rapidly growing interest in replacing these with environmentally friendly and earth-abundant materials. Herein, we report a facile solution-processed fabrication of a self-powered organic-inorganic hybrid photodetector using n-type oriented ZnO nanorods and p-type Spiro-MeOTAD semiconductor. ZnO is eco-friendly and earth-abundant, and Spiro-MeOTAD is non-hazardous. We show that the latter has far less toxicity than the toxic elements stated above. This visible blind UV photodetector shows high sensitivity (102) and a UV/visible rejection ratio of 300. It also exhibits fast response times of ?rise ~ 200 ?s and ?fall ~ 950 ?s. Importantly, with a small modification of nitrogen incorporation in ZnO one can also realize a highly-sensitive self-powered visible light photodetector with at least 1000% (or higher) improvements in quality factors (photocurrent/sensitivity/response time) as compared to previously reported organic-inorganic hybrid photo-detectors based on metal-chalcogenides (CdS-PANI or CuInSe2-P3HT). Interestingly, the broadband sensitivity of such N:ZnO-Spiro-MeOTAD photodiode enables sensing of low intensity (~28 ?W cm-2) ambient white light with a high photocurrent density of 120 nA cm-2 making it an efficient ambient white light detector. Electronic supplementary information (ESI) available: SI-1: response time measurements of self powered hybrid ZnO-SPD under nanosecond pulsed UV laser, SI-2: Raman analysis of N:ZnO and ZnO SI-3: cytotoxicity study on Spiro-MeOTAD SI-4: electrochemical Mott-Schottky plots of ZnO and N:ZnO. See DOI: 10.1039/c3nr04727j

  19. Quantitative Analysis by Isotopic Dilution Using Mass Spectroscopy: The Determination of Caffeine by GC-MS.

    ERIC Educational Resources Information Center

    Hill, Devon W.; And Others

    1988-01-01

    Describes a laboratory technique for quantitative analysis of caffeine by an isotopic dilution method for coupled gas chromatography-mass spectroscopy. Discusses caffeine analysis and experimental methodology. Lists sample caffeine concentrations found in common products. (MVL)

  20. Coherent two-dimensional infrared spectroscopy: Quantitative analysis of protein secondary structure in solution

    E-print Network

    Baiz, Carlos R.

    We present a method to quantitatively determine the secondary structure composition of globular proteins using coherent two-dimensional infrared (2DIR) spectroscopy of backbone amide I vibrations (1550–1720 cm?1). Sixteen ...

  1. Quantitative analysis of sulfur functional groups in natural organic matter by XANES spectroscopy

    E-print Network

    Quantitative analysis of sulfur functional groups in natural organic matter by XANES spectroscopy sulfur functionalities in natural organic matter from S K-edge XANES spectroscopy are presented-induced errors, inherent to the choice of a particular curve, are typically lower than 5% of total sulfur

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

    ERIC Educational Resources Information Center

    Healy, Eamonn F.

    2007-01-01

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

  3. Quantitative biological Raman spectroscopy for non-invasive blood analysis

    E-print Network

    Shih, Wei-Chuan

    2007-01-01

    The long term goal of this project is the measurement of clinically-relevant analytes in the blood tissue matrix of human subjects using near-infrared Raman spectroscopy, with the shorter term research directed towards ...

  4. Quantitative Measurement of Trans-Fats by Infrared Spectroscopy

    ERIC Educational Resources Information Center

    Walker, Edward B.; Davies, Don R.; Campbell, Mike

    2007-01-01

    Trans-fat is a general term, which is mainly used to describe the various trans geometric isomers present in unsaturated fatty acids. Various techniques are now used for a quantitative measurement of the amount of trans-fats present in foods and cooking oil.

  5. Direct and quantitative photothermal absorption spectroscopy of individual particulates

    SciTech Connect

    Tong, Jonathan K.; Hsu, Wei-Chun; Eon Han, Sang; Burg, Brian R.; Chen, Gang; Zheng, Ruiting; Shen, Sheng

    2013-12-23

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

  6. Machine learning methods for quantitative analysis of Raman spectroscopy data

    NASA Astrophysics Data System (ADS)

    Madden, Michael G.; Ryder, Alan G.

    2003-03-01

    The automated identification and quantification of illicit materials using Raman spectroscopy is of significant importance for law enforcement agencies. This paper explores the use of Machine Learning (ML) methods in comparison with standard statistical regression techniques for developing automated identification methods. In this work, the ML task is broken into two sub-tasks, data reduction and prediction. In well-conditioned data, the number of samples should be much larger than the number of attributes per sample, to limit the degrees of freedom in predictive models. In this spectroscopy data, the opposite is normally true. Predictive models based on such data have a high number of degrees of freedom, which increases the risk of models over-fitting to the sample data and having poor predictive power. In the work described here, an approach to data reduction based on Genetic Algorithms is described. For the prediction sub-task, the objective is to estimate the concentration of a component in a mixture, based on its Raman spectrum and the known concentrations of previously seen mixtures. Here, Neural Networks and k-Nearest Neighbours are used for prediction. Preliminary results are presented for the problem of estimating the concentration of cocaine in solid mixtures, and compared with previously published results in which statistical analysis of the same dataset was performed. Finally, this paper demonstrates how more accurate results may be achieved by using an ensemble of prediction techniques.

  7. Quantitative monitoring of yeast fermentation using Raman spectroscopy.

    PubMed

    Iversen, Jens A; Berg, Rolf W; Ahring, Birgitte K

    2014-08-01

    Compared to traditional IR methods, Raman spectroscopy has the advantage of only minimal interference from water when measuring aqueous samples, which makes this method potentially useful for in situ monitoring of important industrial bioprocesses. This study demonstrates real-time monitoring of a Saccharomyces cerevisiae fermentation process using a Raman spectroscopy instrument equipped with a robust sapphire ball probe. A method was developed to correct the Raman signal for the attenuation caused by light scattering cell particulate, hence enabling quantification of reaction components and possibly measurement of yeast cell concentrations. Extinction of Raman intensities to more than 50 % during fermentation was normalized with approximated extinction expressions using Raman signal of water around 1,627 cm(-1) as internal standard to correct for the effect of scattering. Complicated standard multi-variant chemometric techniques, such as PLS, were avoided in the quantification model, as an attempt to keep the monitoring method as simple as possible and still get satisfactory estimations. Instead, estimations were made with a two-step approach, where initial scattering correction of attenuated signals was followed by linear regression. In situ quantification measurements of the fermentation resulted in root mean square errors of prediction (RMSEP) of 2.357, 1.611, and 0.633 g/L for glucose, ethanol, and yeast concentrations, respectively. PMID:24996999

  8. Quantitative multiplex CARS spectroscopy in congested spectral regions

    NASA Astrophysics Data System (ADS)

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

    2007-02-01

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

  9. Enhanced resolution and quantitation from `ultrahigh' eld NMR spectroscopy of glasses

    E-print Network

    Puglisi, Joseph

    Enhanced resolution and quantitation from `ultrahigh' ®eld NMR spectroscopy of glasses Scott for nuclear magnetic resonance (NMR) (e.g., 14.1 and 18.8 T) can enhance both resolution and sensitivity-®eld NMR can yield structural information not always available from NMR experiments of glasses at lower

  10. Quantitative Multiple-Quantum Magic-Angle-Spinning NMR Spectroscopy of Quadrupolar Nuclei in Solids

    E-print Network

    Griffin, Robert G.

    Quantitative Multiple-Quantum Magic-Angle-Spinning NMR Spectroscopy of Quadrupolar Nuclei in Solids, 1996X Abstract: We describe a new approach for observation of multiple-quantum (MQ) NMR spectra populations from isotropic MQ NMR spectra. We illustrate the utility of the approach with 23Na (S ) 3/2) MQ

  11. Quantitative Analysis of Nail Polish Remover Using Nuclear Magnetic Resonance Spectroscopy Revisited

    ERIC Educational Resources Information Center

    Hoffmann, Markus M.; Caccamis, Joshua T.; Heitz, Mark P.; Schlecht, Kenneth D.

    2008-01-01

    Substantial modifications are presented for a previously described experiment using nuclear magnetic resonance (NMR) spectroscopy to quantitatively determine analytes in commercial nail polish remover. The revised experiment is intended for a second- or third-year laboratory course in analytical chemistry and can be conducted for larger laboratory…

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

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

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

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

    PubMed Central

    Xu, Xin-fang; Nie, Li-xing; Pan, Li-li; Hao, Bian; Yuan, Shao-xiong; Lin, Rui-chao; Bu, Hai-bo; Wang, Dan; Dong, Ling; Li, Xiang-ri

    2014-01-01

    Near-infrared spectroscopy (NIRS), a rapid and efficient tool, was used to determine the total amount of nine ginsenosides in Panax ginseng. In the study, the regression models were established using multivariate regression methods with the results from conventional chemical analytical methods as reference values. The multivariate regression methods, partial least squares regression (PLSR) and principal component regression (PCR), were discussed and the PLSR was more suitable. Multiplicative scatter correction (MSC), second derivative, and Savitzky-Golay smoothing were utilized together for the spectral preprocessing. When evaluating the final model, factors such as correlation coefficient (R2) and the root mean square error of prediction (RMSEP) were considered. The final optimal results of PLSR model showed that root mean square error of prediction (RMSEP) and correlation coefficients (R2) in the calibration set were 0.159 and 0.963, respectively. The results demonstrated that the NIRS as a new method can be applied to the quality control of Ginseng Radix et Rhizoma. PMID:24883224

  14. Phosphorene: Synthesis, Scale-Up, and Quantitative Optical Spectroscopy.

    PubMed

    Woomer, Adam H; Farnsworth, Tyler W; Hu, Jun; Wells, Rebekah A; Donley, Carrie L; Warren, Scott C

    2015-09-22

    Phosphorene, a two-dimensional (2D) monolayer of black phosphorus, has attracted considerable theoretical interest, although the experimental realization of monolayer, bilayer, and few-layer flakes has been a significant challenge. Here, we systematically survey conditions for liquid exfoliation to achieve the first large-scale production of monolayer, bilayer, and few-layer phosphorus, with exfoliation demonstrated at the 10 g scale. We describe a rapid approach for quantifying the thickness of 2D phosphorus and show that monolayer and few-layer flakes produced by our approach are crystalline and unoxidized, while air exposure leads to rapid oxidation and the production of acid. With large quantities of 2D phosphorus now available, we perform the first quantitative measurements of the material's absorption edge-which is nearly identical to the material's band gap under our experimental conditions-as a function of flake thickness. Our interpretation of the absorbance spectrum relies on an analytical method introduced in this work, allowing the accurate determination of the absorption edge in polydisperse samples of quantum-confined semiconductors. Using this method, we found that the band gap of black phosphorus increased from 0.33 ± 0.02 eV in bulk to 1.88 ± 0.24 eV in bilayers, a range that is larger than that of any other 2D material. In addition, we quantified a higher-energy optical transition (VB-1 to CB), which changes from 2.0 eV in bulk to 3.23 eV in bilayers. This work describes several methods for producing and analyzing 2D phosphorus while also yielding a class of 2D materials with unprecedented optoelectronic properties. PMID:26256770

  15. Power-scalable tunable UV, visible, and NIR generation from an ultrafast fiber OPA based on four wave mixing in PCF

    NASA Astrophysics Data System (ADS)

    Yarrow, Michael J.; Wadsworth, William J.; Lavoute, Laure; Clowes, John R.; Grudinin, Anatoly B.

    2012-02-01

    An ultrafast fiber MOPA was developed which delivered high average power and rapid and continuous tunability over the range 1035 - 1070 nm. Through FWM in a single PCF, this source generated greater than 30% conversion efficiency to a narrow linewidth signal with tunability from 720 to 880 nm and a corresponding idler tunable from 1370 to 1880 nm. Generation of tunable signal SHG, signal-pump SFG, pump SHG and pump-idler SFG were demonstrated in a single angle tuned BBO crystal. The combined system enabled tunability over large portions of the UV, visible and NIR spectral range from 370 - 1900 nm with a very simple setup. There is scope for power scaling of the source and extending the wavelength coverage.

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

    SciTech Connect

    Felzer, B.; Hauff, P.; Goetz, A.F.H.

    1994-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  18. Application of image processing for terahertz time domain spectroscopy imaging quantitative detection

    NASA Astrophysics Data System (ADS)

    Li, Li-juan; Wang, Sheng; Ren, Jiao-jiao; Zhou, Ming-xing; Zhao, Duo

    2015-03-01

    According to nondestructive testing principle for the terahertz time domain spectroscopy Imaging, using digital image processing techniques, through Terahertz time-domain spectroscopy system collected images and two-dimensional datas and using a range of processing methods, including selecting regions of interest, contrast enhancement, edge detection, and defects being detected. In the paper, Matlab programming is been use to defect recognition of Terahertz, by figuring out the pixels to determine defects defect area and border length, roundness, diameter size. Through the experiment of the qualitative analysis and quantitative calculation of Matlab image processing, this method of detection of defects of geometric dimension of the sample to get a better result.

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

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

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

  20. Screening hypochromism (sieve effect) in red blood cells: a quantitative analysis.

    PubMed

    Razi Naqvi, K

    2014-04-01

    Multiwavelength UV-visible spectroscopy, Kramers-Kronig analysis, and several other experimental and theoretical tools have been applied over the last several decades to fathom absorption and scattering of light by suspensions of micron-sized pigmented particles, including red blood cells, but a satisfactory quantitative analysis of the difference between the absorption spectra of suspension of intact and lysed red blood cells is still lacking. It is stressed that such a comparison is meaningful only if the pertinent spectra are free from, or have been corrected for, scattering losses, and it is shown that Duysens' theory can, whereas that of Vekshin cannot, account satisfactorily for the observed hypochromism of suspensions of red blood cells. PMID:24761307

  1. Screening hypochromism (sieve effect) in red blood cells: a quantitative analysis

    PubMed Central

    Razi Naqvi, K.

    2014-01-01

    Multiwavelength UV-visible spectroscopy, Kramers-Kronig analysis, and several other experimental and theoretical tools have been applied over the last several decades to fathom absorption and scattering of light by suspensions of micron-sized pigmented particles, including red blood cells, but a satisfactory quantitative analysis of the difference between the absorption spectra of suspension of intact and lysed red blood cells is still lacking. It is stressed that such a comparison is meaningful only if the pertinent spectra are free from, or have been corrected for, scattering losses, and it is shown that Duysens’ theory can, whereas that of Vekshin cannot, account satisfactorily for the observed hypochromism of suspensions of red blood cells. PMID:24761307

  2. Quantitative analysis of the mixtures of illicit drugs using terahertz time-domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Jiang, Dejun; Zhao, Shusen; Shen, Jingling

    2008-03-01

    A method was proposed to quantitatively inspect the mixtures of illicit drugs with terahertz time-domain spectroscopy technique. The mass percentages of all components in a mixture can be obtained by linear regression analysis, on the assumption that all components in the mixture and their absorption features be known. For illicit drugs were scarce and expensive, firstly we used common chemicals, Benzophenone, Anthraquinone, Pyridoxine hydrochloride and L-Ascorbic acid in the experiment. Then illicit drugs and a common adulterant, methamphetamine and flour, were selected for our experiment. Experimental results were in significant agreement with actual content, which suggested that it could be an effective method for quantitative identification of illicit drugs.

  3. GUEST EDITORIAL Coherent Multidimensional Optical Spectroscopy

    E-print Network

    Mukamel, Shaul

    ). The signal is double Fourier transformed with respect to the two desired time variables to generate frequency methods of theoretical chem- istry, and stimulate future developments. The most notable dif- ference from, Raman, and UV-visible spectroscopies, provide a one dimensional (1D) projection of the available

  4. Fourier transform infrared spectroscopy quantitative analysis of SF6 partial discharge decomposition components

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoxing; Liu, Heng; Ren, Jiangbo; Li, Jian; Li, Xin

    2015-02-01

    Gas-insulated switchgear (GIS) internal SF6 gas produces specific decomposition components under partial discharge (PD). By detecting these characteristic decomposition components, such information as the type and level of GIS internal insulation deterioration can be obtained effectively, and the status of GIS internal insulation can be evaluated. SF6 was selected as the background gas for Fourier transform infrared spectroscopy (FTIR) detection in this study. SOF2, SO2F2, SO2, and CO were selected as the characteristic decomposition components for system analysis. The standard infrared absorption spectroscopy of the four characteristic components was measured, the optimal absorption peaks were recorded and the corresponding absorption coefficient was calculated. Quantitative detection experiments on the four characteristic components were conducted. The volume fraction variation trend of four characteristic components at different PD time were analyzed. And under five different PD quantity, the quantitative relationships among gas production rate, PD time, and PD quantity were studied.

  5. Fourier transform infrared spectroscopy quantitative analysis of SF6 partial discharge decomposition components.

    PubMed

    Zhang, Xiaoxing; Liu, Heng; Ren, Jiangbo; Li, Jian; Li, Xin

    2015-02-01

    Gas-insulated switchgear (GIS) internal SF6 gas produces specific decomposition components under partial discharge (PD). By detecting these characteristic decomposition components, such information as the type and level of GIS internal insulation deterioration can be obtained effectively, and the status of GIS internal insulation can be evaluated. SF6 was selected as the background gas for Fourier transform infrared spectroscopy (FTIR) detection in this study. SOF2, SO2F2, SO2, and CO were selected as the characteristic decomposition components for system analysis. The standard infrared absorption spectroscopy of the four characteristic components was measured, the optimal absorption peaks were recorded and the corresponding absorption coefficient was calculated. Quantitative detection experiments on the four characteristic components were conducted. The volume fraction variation trend of four characteristic components at different PD time were analyzed. And under five different PD quantity, the quantitative relationships among gas production rate, PD time, and PD quantity were studied. PMID:25459612

  6. Quantitative analysis of essential oils of Thymus daenensis using laser-induced fluorescence and Raman spectroscopy.

    PubMed

    Khoshroo, H; Khadem, H; Bahreini, M; Tavassoli, S H; Hadian, J

    2015-11-10

    Laser-induced fluorescence and Raman spectroscopy are used for the investigation of different genotypes of Thymus daenensis native to the Ilam province of Iran. Different genotypes of T. daenensis essential oils, labeled T1 through T7, possess slight differences with regard to the composition of the thymol. The gas chromatography-mass spectrometry (GC-MS) method is performed to determine the concentration of each constituent as a reference method. The Raman spectra of different concentrations of pure thymol dissolved in hexane as standard samples are obtained via a laboratory prototype Raman spectroscopy setup for the calculation of the calibration curve. The regression coefficient and limit of detection are calculated. The possibility of the differentiation of different genotypes of T. daenensis is also examined by laser-induced fluorescence spectroscopy, although we do not know the exact amounts of their components. All the fluorescence spectral information is used jointly by cluster analysis to differentiate between 7 genotypes. Our results demonstrate the acceptable precision of Raman spectroscopy with GC-MS and corroborate the capacity of Raman spectroscopy in applications in the quantitative analysis field. Furthermore, the cluster analysis results show that laser-induced fluorescence spectroscopy is an acceptable technique for the rapid classification of different genotypes of T. daenensis without having any previous information of their exact amount of constituents. So, the ability to rapidly and nondestructively differentiate between genotypes makes it possible to efficiently select high-quality herbs from many samples. PMID:26560783

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

    PubMed Central

    Craig, Derek; Mazilu, Michael; Dholakia, Kishan

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  9. [A multivariate nonlinear model for quantitative analysis in laser-induced breakdown spectroscopy].

    PubMed

    Chen, Xing-Long; Fu, Hong-Bo; Wang, Jing-Ge; Ni, Zhi-Bo; He, Wen-Gan; Xu, Jun; Rao Rui-zhong; Dong, Rui-Zhong

    2014-11-01

    Most quantitative models used in laser-induced breakdown spectroscopy (LIBS) are based on the hypothesis that laser-induced plasma approaches the state of local thermal equilibrium (LTE). However, the local equilibrium is possible only at a specific time segment during the evolution. As the populations of each energy level does not follow Boltzmann distribution in non-LTE condition, those quantitative models using single spectral line would be inaccurate. A multivariate nonlinear model, in which the LTE is not required, was proposed in this article to reduce the signal fluctuation and improve the accuracy of quantitative analysis. This multivariate nonlinear model was compared with the internal calibration model which is based on the LTE condition. The content of Mn in steel samples was determined by using the two models, respectively. A minor error and a minor relative standard deviation (RSD) were observed in multivariate nonlinear model. This result demonstrates that multivariate nonlinear model can improve measurement accuracy and repeatability. PMID:25752066

  10. Quantitative frequency-domain fluorescence spectroscopy in tissues and tissue-like media

    NASA Astrophysics Data System (ADS)

    Cerussi, Albert Edward

    1999-09-01

    In the never-ending quest for improved medical technology at lower cost, modern near-infrared optical spectroscopy offers the possibility of inexpensive technology for quantitative and non-invasive diagnoses. Hemoglobin is the dominant chromophore in the 700-900 nm spectral region and as such it allows for the optical assessment of hemoglobin concentration and tissue oxygenation by absorption spectroscopy. However, there are many other important physiologically relevant compounds or physiological states that cannot be effectively sensed via optical methods because of poor optical contrast. In such cases, contrast enhancements are required. Fluorescence spectroscopy is an attractive component of optical tissue spectroscopy. Exogenous fluorophores, as well as some endogenous ones, may furnish the desperately needed sensitivity and specificity that is lacking in near-infrared optical tissue spectroscopy. The main focus of this thesis was to investigate the generation and propagation of fluorescence photons inside tissues and tissue-like media (i.e., scattering dominated media). The standard concepts of fluorescence spectroscopy have been incorporated into a diffusion-based picture that is sometimes referred to as photon migration. The novelty of this work lies in the successful quantitative recovery of fluorescence lifetimes, absolute fluorescence quantum yields, fluorophore concentrations, emission spectra, and both scattering and absorption coefficients at the emission wavelength from a tissue-like medium. All of these parameters are sensitive to the fluorophore local environment and hence are indicators of the tissue's physiological state. One application demonstrating the capabilities of frequency-domain lifetime spectroscopy in tissue-like media is a study of the binding of ethidium bromide to bovine leukocytes in fresh milk. Ethidium bromide is a fluorescent dye that is commonly used to label DNA, and hence visualize chromosomes in cells. The lifetime of ethidium bromide increases by an order of magnitude upon binding to DNA. In this thesis, I demonstrated that the fluorescence photon migration model is capable of accurately determining the somatic cell count (SCC) in a milk sample. Although meant as a demonstration of fluorescence tissue spectroscopy, this specific problem has important implications for the dairy industry's warfare against subclinical mastitis (i.e., mammary gland inflammation), since the SCC is often used as an indication of bovine infection.

  11. Determination of Calcium in Cereal with Flame Atomic Absorption Spectroscopy: An Experiment for a Quantitative Methods of Analysis Course

    ERIC Educational Resources Information Center

    Bazzi, Ali; Kreuz, Bette; Fischer, Jeffrey

    2004-01-01

    An experiment for determination of calcium in cereal using two-increment standard addition method in conjunction with flame atomic absorption spectroscopy (FAAS) is demonstrated. The experiment is intended to introduce students to the principles of atomic absorption spectroscopy giving them hands on experience using quantitative methods of…

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

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

    PubMed Central

    Philippe, Allan; Schaumann, Gabriele E.

    2014-01-01

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

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

    PubMed

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

    2014-01-24

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

  16. Quantitative and qualitative analysis of urine component in the toilet set using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Chung, So Hyun; Park, Kwang Suk; Choi, Jong Min; Lee, Won Jin

    2004-07-01

    As a part of non-invasive and unaware measurement of physiological signal in the house of live-alone person, Raman spectroscopy was applied for urine component analysis in the toilet set. 785nm, 250-300mW output solid state diode laser and 2048 element linear silicon TE cooled CCD array were incorporated for this system. Several tests were performed for setting up Raman spectroscopy in non-constrained situation: toilet set in the house. The effect of dark current, integration time, warming up time of laser, property of probe and interference of water in the toilet were tested and controlled for appropriate measurement in this environment. The spectra were obtained immediately when the subject uses the toilet set, and they can be transmitted to the server though Bluetooth. Those spectra were pre-processed for removing or correcting the effect of undesired light scattering, sample path-length difference and baseline-effect. The preprocessed data were enhanced for more exact result of multivariate analysis. The training data was prepared for predicting unknown component and its concentration by using multivariate methods. Several kinds of multivariate methods: PCA, PCR, PLS were performed to validate what is the fittest method in this environment. Through quantitative and qualitative analysis of Raman spectroscopy"s spectra obtained in the house's toilet set, we could know the component and its concentration of urine which can be index of disease.

  17. 13C NMR Spectroscopy for the Quantitative Determination of Compound Ratios and Polymer End Groups

    PubMed Central

    2015-01-01

    13C NMR spectroscopic integration employing short relaxation delays was evaluated as a quantitative tool to obtain ratios of diastereomers, regioisomers, constitutional isomers, mixtures of unrelated compounds, peptoids, and sugars. The results were compared to established quantitative methods such as 1H NMR spectroscopic integration, gas chromatography, and high-performance liquid chromatography and were found to be within <3.4% of 1H NMR spectroscopic values (most examples give results within <2%). Acquisition of the spectra took 2–30 min on as little as 10 mg of sample, proving the general utility of the technique. The simple protocol was extended to include end group analysis of low molecular weight polymers, which afforded results in accordance with 1H NMR spectroscopy and matrix-assisted laser desorption-ionization time-of-flight spectrometry. PMID:24601654

  18. Quantitative Analysis for Monitoring Formulation of Lubricating Oil Using Terahertz Time-Domain Transmission Spectroscopy

    NASA Astrophysics Data System (ADS)

    Tian, Lu; Zhao, Kun; Zhou, Qing-Li; Shi, Yu-Lei; Zhang, Cun-Lin

    2012-04-01

    The quantitative analysis of zinc isopropyl-isooctyl-dithiophosphate (T204) mixed with lube base oil from Korea with viscosity index 70 (T204-Korea70) is presented by using terahertz time-domain spectroscopy (THz-TDS). Compared with the middle-infrared spectra of zinc n-butyl-isooctyl-dithiophosphate (T202) and T204, THz spectra of T202 and T204 show the weak broad absorption bands. Then, the absorption coefficients of the T204-Korea70 system follow Beer's law at the concentration from 0.124 to 4.024%. The experimental absorption spectra of T204-Korea70 agree with the calculated ones based on the standard absorption coefficients of T204 and Korea70. The quantitative analysis enables a strategy to monitor the formulation of lubricating oil in real time.

  19. [Study on the multicomponent quantitative analysis using near infrared spectroscopy based on building elman model].

    PubMed

    Liu, Bo-ping; Qin, Hua-jun; Luo, Xiang; Cao, Shu-wen; Wang, Jun-de

    2007-12-01

    The present paper introduces an application of near infrared spectroscopy (NIRS) multi-component quantitative analysis by building a kind of recurrent network (Elman) model. Elman prediction model for phenylalanine (Phe), lysine (Lys), tyrosine (Tyr) and cystine (Cys) in 45 feedstuff samples was established with good veracity. Twelve peak value data from 3 principal components straight forward compressed from the original data by PLS were taken as inputs of Elman, while 4 predictive targets as outputs. Forty seven nerve cells were taken as hidden nodes with the lowest error compared with taking 43 and 45 nerve cells. Its training iteration times was supposed to be 1000. Predictive correlation coefficients by the model are 0.960, 0.981, 0.979 and 0.952. The results show that Elman using in NIRS is a rapid, effective means for measuring Phe, Lys, Tyr and Cys in feedstuff powder, and can also be used in quantitative analysis of other samples. PMID:18330284

  20. Quantitative determination of uranium and europium in glass matrix by laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Jung, E. C.; Lee, D. H.; Yun, J.-I.; Kim, J. G.; Yeon, J. W.; Song, K.

    2011-09-01

    Laser-induced breakdown spectroscopy was applied to the quantitative determination of the elemental composition of glass samples containing U and Eu as a surrogate for highly radioactive glass waste. The emission intensities of both major and minor elements in the samples were measured simultaneously in the wavelength range from 200 to 780 nm by using an echelle spectrometer. Calibration curves for the concentration determination were obtained from the emission intensities at 358.488 nm for U I, and 459.403 nm for Eu I. Limits of detection for U and Eu were ~ 150 and ~ 4.2 parts per million, respectively.

  1. Quantitative analysis of urinary stone composition with micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Huang, Yi-Yu; Chiu, Yi-Chun; Chiang, Huihua Kenny; Chou, Y. H. Jet; Lu, Shing-Hwa; Chiu, Allen W.

    2010-02-01

    Urolithiasis is a common, disturbing disease with high recurrent rate (60% in five years). Accurate identification of urinary stone composition is important for treatment and prevention purpose. Our previous studies have demonstrated that micro-Raman spectroscopy (MRS)-based approach successfully detects the composition of tiny stone powders after minimal invasive urological surgery. But quantitative analysis of urinary stones was not established yet. In this study, human urinary stone mixed with two compositions of COM, HAP, COD, and uric acid, were analyzed quantitatively by using a 632.98 nm Raman spectrometric system. This quantitative analysis was based on the construction of calibration curves of known mixtures of synthetically prepared pure COM, HAP, COD and uric acid. First, the various concentration (mole fraction) ratio of binary mixtures including COM and HAP, COM and COD, or COM and uric acid, were produced. Second, the intensities of the characteristic bands at 1462cm -1(IRCOM), 1477cm-1(IRCOD), 961cm-1(IRHAP) and 1402cm-1(IRuric acid), for COD, COM, HAP and uric acid were used respectively for intensity calculation. Various binary mixtures of known concentration ratio were recorded as the basis for the quantitative analysis. The ratios of the relative intensities of the Raman bands corresponding to binary mixtures of known composition on the inverse of the COM concentration yielded a linear dependence. Third, urinary stone fragments collected from patients after management were analyzed with the use of the calibration curve and the quantitative analysis of unknown samples was made by the interpolation analysis. We successfully developed a MRS-based quantitative analytical method for measuring two composition.

  2. Comparison between ultraviolet-visible and near-infrared elastic scattering spectroscopy of chemically

    E-print Network

    Bigio, Irving J.

    Comparison between ultraviolet-visible and near- infrared elastic scattering spectroscopy, Massachusetts 02215 Abstract. The work reported compares elastic scattering spectroscopy (ESS) for diagnosis of pigmented skin lesions in two spectral regions: UV-visible and near infrared (NIR). Given the known strong

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    PubMed

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

    2015-10-01

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

  5. Quantitative laser-induced breakdown spectroscopy analysis of calcified tissue samples

    NASA Astrophysics Data System (ADS)

    Samek, O.; Beddows, D. C. S.; Telle, H. H.; Kaiser, J.; Liška, M.; Cáceres, J. O.; Gonzáles Ureña, A.

    2001-06-01

    We report on the application of laser-induced breakdown spectroscopy (LIBS) to the analysis of important minerals and the accumulation of potentially toxic elements in calcified tissue, to trace e.g. the influence of environmental exposure, and other medical or biological factors. This theme was exemplified for quantitative detection and mapping of Al, Pb and Sr in representative samples, including teeth (first teeth of infants, second teeth of children and teeth of adults) and bones (tibia and femur). In addition to identifying and quantifying major and trace elements in the tissues, one- and two-dimensional profiles and maps were generated. Such maps (a) provide time/concentration relations, (b) allow to follow mineralisation of the hydroxyapatite matrix and the migration of the elements within it and (c) enable to identify disease states, such as caries in teeth. In order to obtain quantitative calibration, reference samples in the form of pressed pellets with calcified tissue-equivalent material (majority compound of pellets is CaCO 3) were used whose physical properties closely resembled hydroxyapatite. Compounds of Al, Sr and Pb were added to the pellets, containing atomic concentrations in the range 100-10 000 ppm relative to the Ca content of the matrix. Analytical results based on this calibration against artificial samples for the trace elements under investigation agree with literature values, and with our atomic absorption spectroscopy (AAS) cross-validation measurements.

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

    NASA Astrophysics Data System (ADS)

    Cao, Binghua; Fan, Mengbao

    2010-10-01

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

  7. Monitoring lactic acid production during milk fermentation by in situ quantitative proton nuclear magnetic resonance spectroscopy.

    PubMed

    Bouteille, R; Gaudet, M; Lecanu, B; This, H

    2013-04-01

    When fermenting milk, lactic bacteria convert part of ?- and ?-lactoses into d- and l- lactic acids, causing a pH decrease responsible for casein coagulation. Lactic acid monitoring during fermentation is essential for the control of dairy gel textural and organoleptic properties, and is a way to evaluate strain efficiency. Currently, titrations are used to follow the quantity of acids formed during jellification of milk but they are not specific to lactic acid. An analytical method without the use of any reagent was investigated to quantify lactic acid during milk fermentation: in situ quantitative proton nuclear magnetic resonance spectroscopy. Two methods using in situ quantitative proton nuclear magnetic resonance spectroscopy were compared: (1) d- and l-lactic acids content determination, using the resonance of their methyl protons, showing an increase from 2.06 ± 0.02 to 8.16 ± 0.74 g/L during 240 min of fermentation; and (2) the determination of the ?- and ?-lactoses content, decreasing from 42.68 ± 0.02 to 30.76 ± 1.75 g/L for the same fermentation duration. The ratio between the molar concentrations of produced lactic acids and consumed lactoses enabled cross-validation, as the value (2.02 ± 0.18) is consistent with lactic acid bacteria metabolism. PMID:23403188

  8. Structural Properties and UV-Visible Absorption Spectroscopy of Retinal-pyridyl-CN Re(I) Carbonyl Bipyridine Complex: A Theoretical Study.

    PubMed

    Eng, Julien; Daniel, Chantal

    2015-10-29

    The structural, electronic, and optical properties of the all-trans and five cis conformers of [Re(CO)3(bpy)(ret-pyr-CN)](+) (bpy = 2,2'-bipyridine; ret-pyr-CN = pyridyl-CN-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-2-n)-none-(2,4,6,8-tetraen) were studied in solvent by means of density functional theory (DFT) and time-dependent DFT. The isolated retinal-like chromophore ret-pyr-CN was investigated as well for comparison. By coordination to the complex the two lowest intraligand (IL) states localized on the retinal group are slightly red-shifted from 627 to 690 nm and from 415 to 450 nm, respectively. Several isomerization pathways are open upon irradiation of the Re(I) complex by visible light (400-450 nm), especially to two cis conformers corresponding to the isomerization of the two double bonds of the retinal-like ligand close to the pyridyl group linked to the Re(I) fragment. The metal-to-ligand charge transfer states localized either on the retinal group or on the bpy ligand should play a minor role in the isomerization process itself but could improve its efficiency via ultra-fast intersystem crossing. PMID:26436344

  9. Synthesis, crystal structure, and vibrational spectroscopic and UV-visible studies of Cs{sub 2}MnP{sub 2}O{sub 7}

    SciTech Connect

    Kaoua, Saida; Krimi, Saida; Pechev, Stanislav; Gravereau, Pierre; Chaminade, Jean-Pierre; Couzi, Michel; El Jazouli, Abdelaziz

    2013-02-15

    A new member of the A{sub 2}MP{sub 2}O{sub 7} diphosphate family, Cs{sub 2}MnP{sub 2}O{sub 7}, has been synthesized and structurally characterized. The crystal structure was determined by single crystal X-Ray diffraction. Cs{sub 2}MnP{sub 2}O{sub 7} crystallizes in the orthorhombic system, space group Pnma ( Music-Sharp-Sign 62), with the unit cell parameters a=16.3398(3), b=5.3872(1), c=9.8872(2) A, Z=4 and V=870.33(3) A{sup 3}. The structure parameters were refined to a final R{sub 1}/wR{sub 2}=0.0194/0.0441 for 1650 observed reflections. The 2D framework of Cs{sub 2}MnP{sub 2}O{sub 7} structure consists of P{sub 2}O{sub 7} and MnO{sub 5} units. The corner-shared MnO{sub 5} and P{sub 2}O{sub 7} units are alternately arranged along the b axis to form [(MnO)P{sub 2}O{sub 7}]{sub {infinity}} chains. These chains are interconnected by an oxygen atom to form sheets parallel to the (b, c) plane. The cesium atoms are located between the sheets in 9- and 10-fold coordinated sites. The infrared and Raman vibrational spectra have been investigated. A factor group analysis leads to the determination of internal modes of (P{sub 2}O{sub 7}) groups. UV-visible spectrum consists of weak bands, between 340 and 700 nm, assigned to the forbidden d-d transitions of Mn{sup 2+} ion, and of a strong band around 250 nm, attributed to the O--Mn charge transfer. - Graphical abstract: Structure of Cs{sub 2}MnP{sub 2}O{sub 7}: The 2D structure of Cs{sub 2}MnP{sub 2}O{sub 7} is built from P{sub 2}O{sub 7} diphosphate groups and MnO{sub 5} square pyramids which share corners and form [(MnO)P{sub 2}O{sub 7}]{sub {infinity}} chains along b axis. These chains are interconnected by an oxygen atom to form wavy (MnP{sub 2}O{sub 7}){sup 2-} sheets parallel to the (b, c) plane. The cesium ions are located between these sheets in the inter-layers space, in zigzag positions. Highlights: Black-Right-Pointing-Pointer A new diphosphate, Cs{sub 2}MnP{sub 2}O{sub 7}, has been synthesized and structurally characterized. Black-Right-Pointing-Pointer The structure consists of a 2D framework built up from (MnP{sub 2}O{sub 7}) sheets. Black-Right-Pointing-Pointer The sheets consist of [(MnO)P{sub 2}O{sub 7}]{sub {infinity}} chains formed by P{sub 2}O{sub 7} units and MnO{sub 5} square pyramids. Black-Right-Pointing-Pointer A factor group analysis leads to the determination of internal modes of (P{sub 2}O{sub 7}) groups. Black-Right-Pointing-Pointer UV-visible spectrum consists bands assigned to d-d transitions of Mn{sup 2+} ion and to O--Mn CT.

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

    PubMed

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

    2015-08-01

    In this original work, the Indium oxide (In2O3) thin film is deposited cleanly on microscope glass substrate at different temperatures by spray pyrolysis technique. The physical properties of the films are characterized by XRD, SEM, AFM and AFM measurements. The spectroscopic investigation has been carried out on the results of FT-IR, FT-Raman and UV-Visible. XRD analysis exposed that the structural transformation of films from stoichiometric to non-stoichiometric orientation of the plane vice versa and also found that, the film is polycrystalline in nature having cubic crystal structure with a preferred grain orientation along (222) plane. SEM and AFM studies revealed that, the film with 0.1M at 500°C has spherical grains with uniform dimension. The complete vibrational analysis has been carried out and the optimized parameters are calculated using HF and DFT (CAM-B3LYP, B3LYP and B3PW91) methods with 3-21G(d,p) basis set. Furthermore, NMR chemical shifts are calculated by using the gauge independent atomic orbital (GIAO) technique. The molecular electronic properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, molecular electrostatic potential energy (MEP) analysis and Polarizability first order hyperpolarizability calculations are performed by time dependent DFT (TD-DFT) approach. The energy excitation on electronic structure is investigated and the assignment of the absorption bands in the electronic spectra of steady compound is discussed. The calculated HOMO and LUMO energies showed the enhancement of energy gap by the addition of substitutions with the base molecule. The thermodynamic properties (heat capacity, entropy, and enthalpy) at different temperatures are calculated and interpreted in gas phase. PMID:25827760

  11. Photocatalytic degradation of C.I. Reactive Blue 19 with nitrogen-doped TiO 2 catalysts thin films under UV/visible light

    NASA Astrophysics Data System (ADS)

    Marques, S. M.; Tavares, C. J.; Oliveira, L. F.; Oliveira-Campos, A. M. F.

    2010-11-01

    Nitrogen-doped titania semiconductor thin films, with photocatalytic properties and a high transmittance in the visible range, have been deposited by unbalanced reactive magnetron sputtering on glass substrates, using d.c. pulsed power supplies. In order to increase the photocatalytic efficiency of the titania coatings the authors optimized the sputtering process, namely by using d.c. pulsed currents for better optimization of reactive gas consumption, and doped the coatings with nitrogen. With this combined and synergistic effect it was possible to enhance the catalysts absorption of visible light, by reducing its semiconductor indirect band-gap. By slightly doping the titania films with 0.7-0.9 at.% nitrogen the photocatalytic performance is ameliorated with almost one order of magnitude. This has been achieved by using nitrogen as a co-reactive gas, together with oxygen, when sputtering from a pure titanium target. The as-deposited thin films on glass are mostly amorphous; however, upon a thermal annealing in vacuum at 500 °C, the crystalline phases of anatase and rutile are developed, being anatase the most prominent polymorph. The photocatalytic performance of the N-doped titania films was evaluated by the decomposition of an organic dye (C.I. Reactive Blue 19) with combined UV/visible light irradiation. Furthermore, a mechanism for the degradation of this dye is proposed. The hydrophilic properties of these films have also been studied by means of water contact angle measurements after varied illumination periods; a minimum contact angle of ˜10° was achieved for optimized wettability conditions.

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  13. Feasibility of quantitative diffuse reflectance spectroscopy for targeted measurement of renal ischemia during laparoscopic partial nephrectomy

    NASA Astrophysics Data System (ADS)

    Goel, Utsav O.; Maddox, Michael M.; Elfer, Katherine N.; Dorsey, Philip J.; Wang, Mei; McCaslin, Ian Ross; Brown, J. Quincy; Lee, Benjamin R.

    2014-10-01

    Reduction of warm ischemia time during partial nephrectomy (PN) is critical to minimizing ischemic damage and improving postoperative kidney function, while maintaining tumor resection efficacy. Recently, methods for localizing the effects of warm ischemia to the region of the tumor via selective clamping of higher-order segmental artery branches have been shown to have superior outcomes compared with clamping the main renal artery. However, artery identification can prolong operative time and increase the blood loss and reduce the positive effects of selective ischemia. Quantitative diffuse reflectance spectroscopy (DRS) can provide a convenient, real-time means to aid in artery identification during laparoscopic PN. The feasibility of quantitative DRS for real-time longitudinal measurement of tissue perfusion and vascular oxygenation in laparoscopic nephrectomy was investigated in vivo in six Yorkshire swine kidneys (n=three animals). DRS allowed for rapid identification of ischemic areas after selective vessel occlusion. In addition, the rates of ischemia induction and recovery were compared for main renal artery versus tertiary segmental artery occlusion, and it was found that the tertiary segmental artery occlusion trends toward faster recovery after ischemia, which suggests a potential benefit of selective ischemia. Quantitative DRS could provide a convenient and fast tool for artery identification and evaluation of the depth, spatial extent, and duration of selective tissue ischemia in laparoscopic PN.

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

    NASA Astrophysics Data System (ADS)

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

    2006-02-01

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

  15. Quantitative confocal fluorescence microscopy of dynamic processes by multifocal fluorescence correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Krmpot, Aleksandar J.; Nikoli?, Stanko N.; Vitali, Marco; Papadopoulos, Dimitrios K.; Oasa, Sho; Thyberg, Per; Tisa, Simone; Kinjo, Masataka; Nilsson, Lennart; Gehring, Walter J.; Terenius, Lars; Rigler, Rudolf; Vukojevic, Vladana

    2015-07-01

    Quantitative confocal fluorescence microscopy imaging without scanning is developed for the study of fast dynamical processes. The method relies on the use of massively parallel Fluorescence Correlation Spectroscopy (mpFCS). Simultaneous excitation of fluorescent molecules across the specimen is achieved by passing a single laser beam through a Diffractive Optical Element (DOE) to generate a quadratic illumination matrix of 32×32 light sources. Fluorescence from 1024 illuminated spots is detected in a confocal arrangement by a matching matrix detector consisting of the same number of single-photon avalanche photodiodes (SPADs). Software was developed for data acquisition and fast autoand cross-correlation analysis by parallel signal processing using a Graphic Processing Unit (GPU). Instrumental performance was assessed using a conventional single-beam FCS instrument as a reference. Versatility of the approach for application in biomedical research was evaluated using ex vivo salivary glands from Drosophila third instar larvae expressing a fluorescently-tagged transcription factor Sex Combs Reduced (Scr) and live PC12 cells stably expressing the fluorescently tagged mu-opioid receptor (MOPeGFP). We show that quantitative mapping of local concentration and mobility of transcription factor molecules across the specimen can be achieved using this approach, which paves the way for future quantitative characterization of dynamical reaction-diffusion landscapes across live cells/tissue with a submillisecond temporal resolution (presently 21 ?s/frame) and single-molecule sensitivity.

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

    PubMed

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

    2011-01-01

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

  17. Quantitative characterization of traumatic bruises by combined pulsed photothermal radiometry and diffuse reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Vidovi?, Luka; Milani?, Matija; Randeberg, Lise L.; Majaron, Boris

    2015-02-01

    We apply diffuse reflectance spectroscopy (DRS) and pulsed photothermal radiometry (PPTR) for characterization of the bruise evolution process. While DRS provides information in a wide range of visible wavelengths, the PPTR enables extraction of detailed depth distribution and concentration profiles of selected absorbers (e.g. melanin, hemoglobin). In this study, we simulate experimental DRS spectra and PPTR signals using the Monte Carlo technique and focus on characterization of a suitable fitting approach for their analysis. We find inverse Monte Carlo to be superior to the diffusion approximation approach for the inverse analysis of DRS spectra. The analysis is then augmented with information obtainable by the fitting of the PPTR signal. We show that both techniques can be coupled in a combined fitting approach. The combining of two complementary techniques improves the robustness and accuracy of the inverse analysis, enabling a comprehensive quantitative characterization of the bruise evolution dynamics.

  18. Quantitative laser-induced breakdown spectroscopy of standard reference materials of various categories

    NASA Astrophysics Data System (ADS)

    Choi, Soo-Jin; Lee, Kang-Jae; Yoh, Jack J.

    2013-12-01

    The quantitative laser-induced breakdown spectroscopy analysis was carried out with standard reference materials (SRM). In order to minimize errors due to the matrix effect, we used 21 SRM samples that belong to different categories of food, clay, sludge, steelmaking alloy, and geochemical and agricultural materials. The principal component analysis was used for rapid identification and discrimination of the samples. Nine elements (Al, Ca, Mg, Ti, Si, Fe, K, Na, and Mn) in each sample were analyzed. While each category of samples shows a specific tendency in the calibration curves of Na, Ti, Si, Al, Fe, and Mn, other elements (K, Ca, and Mg) do not pose any noticeable similarity. The present results establish benchmark calibration curves for characterizing various SRMs.

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

    SciTech Connect

    Mann, C.K.; Vickers, T.J.

    1994-10-11

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

  20. Terahertz time-domain spectroscopy and quantitative analysis of metal gluconates.

    PubMed

    Li, Shaoxian; Yang, Jingqi; Zhao, Hongwei; Yang, Na; Jing, Dandan; Zhang, Jianbing; Li, Qingnuan; Han, Jiaguang

    2015-01-01

    A series of metal gluconates (Na(+), K(+), Mg(2+), Ca(2+), Fe(2+), Cu(2+), and Zn(2+)) were investigated by terahertz (THz) time-domain spectroscopy. The absorption coefficients and refractive indices of the samples were obtained in the frequency range of 0.5-2.6 THz. The gluconates showed distinct THz characteristic fingerprints, and the dissimilarities reflect their different structures, hydrogen-bond networks, and molecular interactions. In addition, some common features were observed among these gluconates, and the similarities probably come from the similar carbohydrate anion group. The X-ray powder diffraction measurements of these metal gluconates were performed, and the copper(II) gluconate was found to be amorphous, corresponding to the monotonic increase feature in the THz absorption spectrum. The results suggest that THz spectroscopy is sensitive to molecular structure and physical form. Binary and ternary mixtures of different gluconates were quantitatively analyzed based on the Beer-Lambert law. A chemical map of a tablet containing calcium D-gluconate monohydrate and ?-lactose in the polyethylene host was obtained by THz imaging. The study shows that THz technology is a useful tool in pharmaceutical research and quality control applications. PMID:25506686

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

    SciTech Connect

    Martinez, Eugenie; Herrera-Gomez, Alberto; Allain, Mickael; Renault, Olivier; Faure, Alain; Chabli, Amal; Bertin, Francois

    2012-07-15

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

  2. Quantitative depth profiling of layered samples using phase-modulation FT-IR photoacoustic spectroscopy

    SciTech Connect

    Jones, R.W.; McClelland, J.F. |

    1996-10-01

    In phase-modulation FT-IR spectroscopy, all wavelengths in a spectrum are modulated at the same frequency and in phase. This factor makes the use of photoacoustic phase data for depth profiling samples much easier in phase modulation than in rapid scan. A method to quantitatively measure layer thickness by using the phase of a substrate spectrum peak is demonstrated with a series of samples consisting of thin polymer films on substrates. Additions to the basic method are demonstrated that extend its application to cases where the substrate peak is overlapped by a spectrum peak of the surface film. A linear relationship between phase angle and layer thickness extending to thicknesses greater than twice the thermal diffusion length is demonstrated. Representations of phase modulation data as a family of angle-specific spectra, as magnitude vs. phase curves, and as a power spectrum and phase spectrum pair, each of which is useful for different aspects of depth profiling, are discussed. Calculating these representations from a single pair of orthogonal interferograms is described. {copyright} {ital 1996} {ital Society for Applied Spectroscopy}

  3. Raman spectroscopy of human skin: looking for a quantitative algorithm to reliably estimate human age

    NASA Astrophysics Data System (ADS)

    Pezzotti, Giuseppe; Boffelli, Marco; Miyamori, Daisuke; Uemura, Takeshi; Marunaka, Yoshinori; Zhu, Wenliang; Ikegaya, Hiroshi

    2015-06-01

    The possibility of examining soft tissues by Raman spectroscopy is challenged in an attempt to probe human age for the changes in biochemical composition of skin that accompany aging. We present a proof-of-concept report for explicating the biophysical links between vibrational characteristics and the specific compositional and chemical changes associated with aging. The actual existence of such links is then phenomenologically proved. In an attempt to foster the basics for a quantitative use of Raman spectroscopy in assessing aging from human skin samples, a precise spectral deconvolution is performed as a function of donors' ages on five cadaveric samples, which emphasizes the physical significance and the morphological modifications of the Raman bands. The outputs suggest the presence of spectral markers for age identification from skin samples. Some of them appeared as authentic "biological clocks" for the apparent exactness with which they are related to age. Our spectroscopic approach yields clear compositional information of protein folding and crystallization of lipid structures, which can lead to a precise identification of age from infants to adults. Once statistically validated, these parameters might be used to link vibrational aspects at the molecular scale for practical forensic purposes.

  4. Quantitative Analysis of Mg in Pipeline Dirt Based on Laser-Induced Breakdown Spectroscopy

    NASA Astrophysics Data System (ADS)

    Wang, Shaolong; Wang, Yangen; Chen, Shanjun; Chen, Qi

    2015-08-01

    In order to maintain the pipeline better and remove the dirt more effectively, it was necessary to analyze the contents of elements in dirt. Mg in soil outside of the pipe and the dirt inside of the pipe was quantitatively analyzed and compared by using the laser-induced breakdown spectroscopy (LIBS). Firstly, Mg was quantitatively analyzed on the basis of Mg I 285.213 nm by calibration curve for integrated intensity and peak intensity of the spectrum before and after subtracting noise, respectively. Then calibration curves on the basis of Mg II 279.553 nm and Mg II 280.270 nm were analyzed. The results indicated that it is better to use integrated intensity after subtracting noise of the spectrum line with high relative intensity to make the calibration curve. supported partly by the Natural Science Foundation of Hubei Province, China (No. 2012FFB00105) and partly by the Science Research Program of Education Department of Hubei Province, China (No. B2013288)

  5. Quantitative analysis of paracetamol polymorphs in powder mixtures by FT-Raman spectroscopy and PLS regression.

    PubMed

    Kachrimanis, Kyriakos; Braun, Doris E; Griesser, Ulrich J

    2007-01-17

    A fast and simple method for the quantitative analysis of monoclinic (form I) and orthorhombic (form II) paracetamol was developed, based on FT-Raman spectroscopy and PLS regression. Three different preprocessing algorithms, namely orthogonal signal correction (OSC), standard normal variate transformation (SNV) and multiplicative scatter correction (MSC), were applied in order to eliminate effects caused by sample preparation and sample inhomogeneities. Subsequently, PLS regression models were fitted and their predictive performance was evaluated on the basis of the root mean squared error of cross-validation (RMSECV) over the complete data set. Furthermore, the data were split into two equal-sized training and test subsets by the Kennard-Stone design and the errors of calibration (RMSEC) and prediction (RMSEP) were calculated. It was found that the OSC preprocessing contributes to a significant increase in the predictive performance of the PLS regression model (RMSECV=0.500%, RMSEC=0.842% and RMSEP=0.538%) in the overall concentration range of form I, compared to the SNV (RMSECV=2.398%, RMSEC=0.911% and RMSEP=7.177%) and MSC (RMSECV=2.7648%, RMSEC=1.572% and RMSEP=4.838%). In addition, the model developed on OSC preprocessed data is more parsimonious, requiring a single latent variable, compared to three latent variables required by the models fitted to the SNV and MSC preprocessed data. The proposed multivariate calibration presents a significant improvement over existing methods for the quantitation of paracetamol polymorphs. PMID:16935450

  6. [Multicomponent quantitative analysis using near infrared spectroscopy by building PLS-GRNN model].

    PubMed

    Liu, Bo-Ping; Qin, Hua-Jun; Luo, Xiang; Cao, Shu-Wen; Wang, Jun-De

    2007-11-01

    The present paper introduces an application of near infrared spectroscopy(NIRS) multi-component quantitative analysis by building partial least squares (PLS)-generalized regression neural networks (GRNN) model. The PLS-GRNN prediction model for chlorine, fibre and fat in 45 feedstuff samples was established with good veracity and recurrence. Eight peak values in principal components compressed from original data by PLS and four in original spectra were taken as inputs of GRNN while 4 predictive targets as outputs. 0.1 was chosen as smoothing factor for its good approximation and prediction with the lowest error compared with 0.2, 0.3, 0.4 and 0.5. Predictive correlation coefficient and Standard error of the estimate of three components by the model are 0.984 0, 0.987 0 and 0.983 0, and 0.015 89, 0.154 1 and 0.115 1, while the Standard deviations of an unknown sample scanned 8 times are 0.003 26, 0.065 5 and 0.031 4. The results show that PLS-GRNN used in NIRS is a rapid, effective means for measuring chlorine, fibre in the fat in feedstuff powder, and can also be used in quantitative analysis of other samples. A settlement in the high error of prediction of other samples with lower contents was also shown. PMID:18260398

  7. [Qualitative-Quantitative Analysis of Rice Bran Oil Adulteration Based on Laser Near Infrared Spectroscopy].

    PubMed

    Tu, Bin; Song, Zhi-qiang; Zheng, Xiao; Zeng, Lu-lu; Yin, Cheng; He, Dong-ping; Qi, Pei-shi

    2015-06-01

    The purpose of this study is mainly to have qualitative-quantitative analysis on the adulteration in rice bran oil by near-infrared spectroscopy analytical technology combined with chemo metrics methods. The author configured 189 adulterated oil samples according to the different mass ratios by selecting rice bran oil as base oil and choosing soybean oil, corn oil, colza oil, and waste oil of catering industry as adulterated oil. Then, the spectral data of samples was collected by using near-infrared spectrometer, and it was pre-processed through the following methods, including without processing, Multiplicative Scatter Correction(MSC), Orthogonal Signal Correction(OSC), Standard Normal Variate and Standard Normal Variate transformation DeTrending(SNV_DT). Furthermore, this article extracted characteristic wavelengths of the spectral datum from the pre-processed date by Successive Projections Algorithm(SPA), established qualitatively classified calibration methods of adulterated oil through classification method of Support Vector Machine(SVM), optimized model parameters(C, g) by Mesh Search Algorithm and determined the optimal process condition. In extracting characteristic wavelengths of the spectral datum from pretreatment by Backward interval Partial Least Squares(BiPLS) and SPA, quantitatively classified calibration models of adulterated oil through Partial Least Squares(PLS) and Support Vector Machine Regression(SVR) was established respectively. In the end, the author optimized the combination of model parameters(C, g) by Mesh Search Algorithm and determined the optimal parameter model. According to the analysis, the accuracy of prediction set and calibration set for SVC model reached 95% and 100% respectively. Compared with the prediction of the adulteration oil content of rice bran oil which was established by the PLS model, the SVR model is the better one, although both of them could implement the content prediction. Furthermore, the correlation coefficient R is above 0.99 and the Root Mean Square Error (MSE) is below 5.55 x 10(-4). The results show that the near-infrared spectroscopy technology is effective in qualitative-quantitative analysis on the adulteration of rice bran oil. And the method is applicable to analyze adulteration in other oils. PMID:26601363

  8. Quantitative characterization of the ,,D2O...3 torsional manifold by terahertz laser spectroscopy and theoretical analysis

    E-print Network

    Cohen, Ronald C.

    of the trimer torsional and hydrogen bond stretch/bend vibrational modes which underlies the torsional model,16 All of these spectra have been observed in the ``torsional band'' or ``bending band'' region of liquidQuantitative characterization of the ,,D2O...3 torsional manifold by terahertz laser spectroscopy

  9. A Quantitative Near-Infrared Spectroscopy Study: A Decrease in Cerebral Hemoglobin Oxygenation in Alzheimer's Disease and Mild Cognitive Impairment

    ERIC Educational Resources Information Center

    Arai, Heii; Takano, Maki; Miyakawa, Koichi; Ota, Tsuneyoshi; Takahashi, Tadashi; Asaka, Hirokazu; Kawaguchi, Tsuneaki

    2006-01-01

    A newly developed quantitative near-infrared spectroscopy (NIRS) system was used to measure changes in cortical hemoglobin oxygenation during the Verbal Fluency Task in 32 healthy controls, 15 subjects with mild cognitive impairment (MCI), and 15 patients with Alzheimer's disease (AD). The amplitude of changes in the waveform, which was…

  10. The Lightning Rod Model: Quantitative Near-Field Spectroscopy for Extraction of Nano-Resolved Optical Constants

    E-print Network

    McLeod, Alexander S; Goldflam, M D; Gainsforth, Zack; Dominguez, Gerardo; Thiemens, Mark; Fogler, Michael M; Basov, D N

    2013-01-01

    Near-field infrared spectroscopy by elastic scattering of light from a probe tip resolves optical contrasts in materials at dramatically sub-wavelength scales across a broad energy range, with the potential for chemical identification at the nanoscale. However, current models of the probe-sample near-field interaction still cannot provide a sufficiently quantitatively interpretation of measured near-field contrasts, especially in the case of materials supporting strong surface phonons. We present a model of near-field spectroscopy derived from basic principles and verified by finite-element simulations, which demonstrates superb predictive agreement with newly presented infrared near-field measurements of both SiO2 thin films and SiC, measured by tunable quantum cascade laser and nanoscale Fourier transform infrared (nanoFTIR) spectroscopy. We discuss the role of probe geometry, field retardation, and surface mode dispersion in shaping the measured near-field response. This treatment offers a route to quantit...

  11. [Quantitative analysis of thiram by surface-enhanced raman spectroscopy combined with feature extraction Algorithms].

    PubMed

    Zhang, Bao-hua; Jiang, Yong-cheng; Sha, Wen; Zhang, Xian-yi; Cui, Zhi-feng

    2015-02-01

    Three feature extraction algorithms, such as the principal component analysis (PCA), the discrete cosine transform (DCT) and the non-negative factorization (NMF), were used to extract the main information of the spectral data in order to weaken the influence of the spectral fluctuation on the subsequent quantitative analysis results based on the SERS spectra of the pesticide thiram. Then the extracted components were respectively combined with the linear regression algorithm--the partial least square regression (PLSR) and the non-linear regression algorithm--the support vector machine regression (SVR) to develop the quantitative analysis models. Finally, the effect of the different feature extraction algorithms on the different kinds of the regression algorithms was evaluated by using 5-fold cross-validation method. The experiments demonstrate that the analysis results of SVR are better than PLSR for the non-linear relationship between the intensity of the SERS spectrum and the concentration of the analyte. Further, the feature extraction algorithms can significantly improve the analysis results regardless of the regression algorithms which mainly due to extracting the main information of the source spectral data and eliminating the fluctuation. Additionally, PCA performs best on the linear regression model and NMF is best on the non-linear model, and the predictive error can be reduced nearly three times in the best case. The root mean square error of cross-validation of the best regression model (NMF+SVR) is 0.0455 micormol x L(-1) (10(-6) mol x L(-1)), and it attains the national detection limit of thiram, so the method in this study provides a novel method for the fast detection of thiram. In conclusion, the study provides the experimental references the selecting the feature extraction algorithms on the analysis of the SERS spectrum, and some common findings of feature extraction can also help processing of other kinds of spectroscopy. PMID:25970898

  12. Quantitative elemental detection of size-segregated particles using laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Wang, Zhen Zhen; Deguchi, Yoshihiro; Kuwahara, Masakazu; Taira, Takuya; Zhang, Xiao Bo; Yan, Jun Jie; Liu, Ji Ping; Watanabe, Hiroaki; Kurose, Ryoichi

    2013-09-01

    In order to simulate coal combustion and develop optimal and stable boiler control systems in real power plants, it is imperative to obtain the detailed information in coal combustion processes as well as to measure species contents in fly ash, which should be controlled and analyzed for enhancing boiler efficiency and reducing environmental pollution. The fly ash consists of oxides (SiO2, Al2O3, Fe2O3, CaO, and so on), unburned carbon, and other minor elements. Recently laser-induced breakdown spectroscopy (LIBS) technique has been applied to coal combustion and other industrial fields because of the fast response, high sensitivity, real-time and non-contact features. In these applications it is important to measure controlling factors without any sample preparation to maintain the real-time measurement feature. The relation between particle content and particle diameter is also one of the vital researches, because compositions of particles are dependent on their diameter. In this study, we have detected the contents of size-segregated particles using LIBS. Particles were classified by an Anderson cascade impactor and their contents were measured using the output of 1064 nm YAG laser, a spectrograph and an ICCD camera. The plasma conditions such as plasma temperature are dependent on the size of particles and these effects must be corrected to obtain quantitative information. The plasma temperature was corrected by the emission intensity ratio from the same atom. Using this correction method, the contents of particles can be measured quantitatively in fixed experimental parameters. This method was applied to coal and fly ash from a coal-fired burner to measure unburned carbon and other contents according to the particle diameter. The acquired results demonstrate that the LIBS technique is applicable to measure size-segregated particle contents in real time and this method is useful for the analysis of coal combustion and its control because of its sensitive and fast analysis features.

  13. Quantitative orientation measurements in thin lipid films by attenuated total reflection infrared spectroscopy.

    PubMed Central

    Picard, F; Buffeteau, T; Desbat, B; Auger, M; Pézolet, M

    1999-01-01

    Quantitative orientation measurements by attenuated total reflectance (ATR) infrared spectroscopy require the accurate knowledge of the dichroic ratio and of the mean-square electric fields along the three axes of the ATR crystal. In this paper, polarized ATR spectra of single supported bilayers of the phospholipid dimyristoylphosphatidic acid covered by either air or water have been recorded and the dichroic ratio of the bands due to the methylene stretching vibrations has been calculated. The mean-square electric field amplitudes were calculated using three formalisms, namely the Harrick thin film approximation, the two-phase approximation, and the thickness- and absorption-dependent one. The results show that for dry bilayers, the acyl chain tilt angle varies with the formalism used, while no significant variations are observed for the hydrated bilayers. To test the validity of the different formalisms, s- and p-polarized ATR spectra of a 40-A lipid layer were simulated for different acyl chain tilt angles. The results show that the thickness- and absorption-dependent formalism using the mean values of the electric fields over the film thickness gives the most accurate values of acyl chain tilt angle in dry lipid films. However, for lipid monolayers or bilayers, the tilt angle can be determined with an acceptable accuracy using the Harrick thin film approximation. Finally, this study shows clearly that the uncertainty on the determination of the tilt angle comes mostly from the experimental error on the dichroic ratio and from the knowledge of the refractive index. PMID:9876167

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

    PubMed

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

    2012-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  16. Quantitative identification of metastable magnesium carbonate minerals by solid-state 13C NMR spectroscopy.

    PubMed

    Moore, Jeremy K; Surface, J Andrew; Brenner, Allison; Wang, Louis S; Skemer, Philip; Conradi, Mark S; Hayes, Sophia E

    2015-01-01

    In the conversion of CO2 to mineral carbonates for the permanent geosequestration of CO2, there are multiple magnesium carbonate phases that are potential reaction products. Solid-state (13)C NMR is demonstrated as an effective tool for distinguishing magnesium carbonate phases and quantitatively characterizing magnesium carbonate mixtures. Several of these mineral phases include magnesite, hydromagnesite, dypingite, and nesquehonite, which differ in composition by the number of waters of hydration or the number of crystallographic hydroxyl groups. These carbonates often form in mixtures with nearly overlapping (13)C NMR resonances which makes their identification and analysis difficult. In this study, these phases have been investigated with solid-state (13)C NMR spectroscopy, including both static and magic-angle spinning (MAS) experiments. Static spectra yield chemical shift anisotropy (CSA) lineshapes that are indicative of the site-symmetry variations of the carbon environments. MAS spectra yield isotropic chemical shifts for each crystallographically inequivalent carbon and spin-lattice relaxation times, T1, yield characteristic information that assist in species discrimination. These detailed parameters, and the combination of static and MAS analyses, can aid investigations of mixed carbonates by (13)C NMR. PMID:25437754

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

    NASA Astrophysics Data System (ADS)

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

    2009-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    SciTech Connect

    Ding, Z. J.; Tan, W. S.; Li, Y. G.

    2006-04-15

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

  20. A calculation of backscattering factor database for quantitative analysis by Auger electron spectroscopy

    SciTech Connect

    Zeng, R. G.; Ding, Z. J.; Li, Y. G.; Mao, S. F.

    2008-12-01

    A systematic calculation of the backscattering factor in quantitative analysis by Auger electron spectroscopy has been performed for the primary electron beam of energy from the threshold energy of inner-shell ionization to 30 keV at the incident angle of 0 deg. - 89 deg. and for principal Auger transition and Auger electrons emitted from over 28 pure elements at an emission angle of 0 deg. - 89 deg. by using a Monte Carlo simulation method. The calculation employs a general definition of backscattering factor, Casnati's ionization cross section, up-to-date Monte Carlo model of electron scattering, and a large number of electron trajectories to ensure less statistical error. Both the configuration geometry of concentric hemispherical analyzer and the cylindrical mirror analyzer for Auger electron detection are considered in the calculation. The calculated backscattering factors are found to describe very well an experimental dependence of Auger electron intensity on primary energy and on incident angle for Si, Cu, Ag, and W in literature. The calculated numerical values of backscattering factor are stored in an open and online database at http://micro.ustc.edu.cn/BSFDataBase/BFAES.htm.

  1. Quantitative analysis of metformin in antidiabetic tablets by laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Contreras, U.; Ornelas-Soto, N.; Meneses-Nava, M. A.; Barbosa-García, O.; López-de-Alba, P. L.; López-Martínez, L.

    2011-09-01

    Nowadays the production of counterfeit and low quality drugs affects human health and generates losses to pharmaceutical industries and tax revenue losses to government. Currently there are several methods for pharmaceutical product analysis; nevertheless, most of them depend on complex and time consuming steps such as sample preparation. In contrast to conventional methods, Laser-induced breakdown spectroscopy (LIBS) is evaluated as a potential analytical technique for the rapid screening and quality control of anti-diabetic solid formulations. In this paper authors propose a simple method to analyze qualitatively and quantitatively Active Pharmaceutical Ingredients (APIs) such as Metformin hydrochloride. The authors used ten nanosecond duration pulses (FWHM) from a Nd:YAG laser produces the induced breakdown for the analysis. Light is collected and focused into a Cerny-Turner spectrograph and dispersed into an ICCD camera for its detection. We used atomic emissions from Chlorine atoms present only in APIs as analyte signal. The analysis was improved using Bromine as internal standard. Linear calibration curves from synthetic samples were prepared achieving linearity higher than 99%. Our results were compared with HPLC results and validation was performed by statistical methods. The validation analysis suggests that both methods have no significant differences i.e., the proposed method can be implemented for monitoring the pharmaceutical production process in-situ in real time or for inspection and recognition of authenticity.

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

    NASA Astrophysics Data System (ADS)

    Fan, Yuxia; Cheng, Fang; Xie, Lijuan

    2010-04-01

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

  3. Quantitative Analysis of Naturally Colored Cotton and White Cotton Blends by UV-VIS Diffuse Reflectance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Hu, X.; Zhang, Q.; Yu, H.; Zhao, D.; Dong, S.; Zhou, W.; Tang, Z.

    2015-01-01

    A new method was discussed to quantitatively analyze the blend ratio of naturally colored cotton (NCC) and white cotton (WC) by UV-vis diffuse reflectance spectroscopy (UV-vis DRS). Three kinds of spectroscopy parameters, diffuse reflectance, reflection absorbance, and the K-M function, were used to correlate them with the blend ratio of NCC/ WC fibers. The results showed that diffuse reflectance and blending ratio had the highest correlation coefficients. Therefore this method can be widely used to quantify the blending ratio of NCC/WC fibers as a result of its greater accuracy and simplicity compared to traditional detection methods.

  4. First quantitative measurements by IR spectroscopy of dioxins and furans by means of broadly tunable quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Siciliani de Cumis, M.; D'Amato, F.; Viciani, S.; Patrizi, B.; Foggi, P.; Galea, C. L.

    2013-02-01

    We demonstrate the possibility of a quantitative analysis of the concentration of several dioxins and furans, among the most toxic ones, by only using infrared absorption laser spectroscopy. Two broadly tunable quantum cascade lasers, emitting in the mid-infrared, have been used to measure the absorption spectra of dioxins and furans, dissolved in CCl4, in direct absorption mode. The minimum detectable concentrations are inferred by analyzing diluted samples. A comparison between this technique and standard Fourier transform spectroscopy has been carried out and an analysis of future perspectives is reported.

  5. Quantitative assessment of hydrocarbon contamination in soil using reflectance spectroscopy: a "multipath" approach.

    PubMed

    Schwartz, Guy; Ben-Dor, Eyal; Eshel, Gil

    2013-11-01

    Petroleum hydrocarbons are contaminants of great significance. The commonly used analytic method for assessing total petroleum hydrocarbons (TPH) in soil samples is based on extraction with 1,1,2-Trichlorotrifluoroethane (Freon 113), a substance prohibited to use by the Environmental Protection Agency. During the past 20 years, a new quantitative methodology that uses the reflected radiation of solids has been widely adopted. By using this approach, the reflectance radiation across the visible, near infrared-shortwave infrared region (400-2500 nm) is modeled against constituents determined using traditional analytic chemistry methods and then used to predict unknown samples. This technology is environmentally friendly and permits rapid and cost-effective measurements of large numbers of samples. Thus, this method dramatically reduces chemical analytical costs and secondary pollution, enabling a new dimension of environmental monitoring. In this study we adapted this approach and developed effective steps in which hydrocarbon contamination in soils can be determined rapidly, accurately, and cost effectively solely from reflectance spectroscopy. Artificial contaminated samples were analyzed chemically and spectrally to form a database of five soils contaminated with three types of petroleum hydrocarbons (PHCs), creating 15 datasets of 48 samples each at contamination levels of 50-5000 wt% ppm (parts per million). A brute force preprocessing approach was used by combining eight different preprocessing techniques with all possible datasets, resulting in 120 different mutations for each dataset. The brute force was done based on an innovative computing system developed for this study. A new parameter for evaluating model performance scoring (MPS) is proposed based on a combination of several common statistical parameters. The effect of dividing the data into training validation and test sets on modeling accuracy is also discussed. The results of this study clearly show that predicting TPH levels at low concentrations in selected soils at high precision levels is viable. Dividing a dataset into training, validation, and test groups affects the modeling process, and different preprocessing methods, alone or in combination, need to be selected based on soil type and PHC type. MPS was found to be a better parameter for selecting the best performing model than ratio of prediction to deviation, yielding models with the same performance but less complicated and more stable. The use of the "all possibilities" system proved to be mandatory for efficient optimal modeling of reflectance spectroscopy data. PMID:24160885

  6. Assessment of breast tumor margins via quantitative diffuse reflectance imaging

    NASA Astrophysics Data System (ADS)

    Brown, J. Quincy; Bydlon, Torre M.; Kennedy, Stephanie A.; Geradts, Joseph; Wilke, Lee G.; Barry, William; Richards, Lisa M.; Junker, Marlee K.; Gallagher, Jennifer; Ramanujam, Nimmi

    2010-02-01

    A particular application of interest for tissue reflectance spectroscopy in the UV-Visible is intraoperative detection of residual cancer at the margins of excised breast tumors, which could prevent costly and unnecessary repeat surgeries. Our multi-disciplinary group has developed an optical imaging device, which is capable of surveying the entire specimen surface down to a depth of 1-2mm, all within a short time as required for intraoperative use. In an IRB-approved study, reflectance spectral images were acquired from 54 margins in 48 patients. Conversion of the spectral images to quantitative tissue parameter maps was facilitated by a fast scalable inverse Monte-Carlo model. Data from margin parameter images were reduced to image-descriptive scalar values and compared to gold-standard margin pathology. The utility of the device for classification of margins was determined via the use of a conditional inference tree modeling approach, and was assessed both as a function of type of disease present at the margin, as well as a function of distance of disease from the issue surface. Additionally, the influence of breast density on the diagnostic parameters, as well as the accuracy of the device, was evaluated.

  7. Ni speciation in a New Caledonian lateritic regolith: A quantitative X-ray absorption spectroscopy investigation

    NASA Astrophysics Data System (ADS)

    Dublet, Gabrielle; Juillot, Farid; Morin, Guillaume; Fritsch, Emmanuel; Fandeur, Dik; Ona-Nguema, Georges; Brown, Gordon E.

    2012-10-01

    Changes in Ni speciation in a 64 m vertical profile of a New Caledonian saprolitic-lateritic regolith developed over ultramafic rocks under tropical weathering conditions were investigated by EXAFS spectroscopy. Quantitative analysis of the EXAFS spectra by linear combination-least squares fitting (LC-LSF) using a large set of model compound spectra showed that Ni hosted in primary silicate minerals (olivine and serpentine) in the bedrock is incorporated in secondary phyllosilicates (serpentine) and Fe-oxides (goethite) in the saprolite unit and mainly in goethite in the laterite unit. A significant concentration of Ni (up to 30% of total Ni) is also hosted by Mn-oxides in the transition laterite (i.e. the lowest part of the laterite unit which contains large amounts of Mn-oxides). However, the amount of Ni associated with Mn-oxides does not exceed 20% of the total Ni in the overlying laterite unit. This sequence of Ni species from bedrock to laterite yields information about the behavior of Ni during tropical weathering of ultramafic rocks. The different Ni distributions in phyllosilicates in the bedrock (randomly distributed) and in the saprolite unit (clustered) indicate two generations of Ni-bearing phyllosilicates. The first, which formed at higher temperature, is related to serpentinization of oceanic crust, whereas the second one, which formed at lower temperature, is associated with post-obduction weathering of ultramafic rocks. In addition, the observed decrease in the proportion of Ni hosted by Mn-oxides from the transition laterite to the upper lateritic horizons indicates dissolution of Mn-oxides during the last stages of differentiation of the lateritic regolith (i.e. lateritization). Finally, the ubiquitous occurrence of Ni-bearing goethite emphasizes the major role of this phase in Ni speciation at the different weathering stages and suggests that goethite represents the major host for Ni in the final tropical weathering stages of New Caledonian ultramafic rocks.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  9. Application of terahertz time-domain spectroscopy combined with chemometrics to quantitative analysis of imidacloprid in rice samples

    NASA Astrophysics Data System (ADS)

    Chen, Zewei; Zhang, Zhuoyong; Zhu, Ruohua; Xiang, Yuhong; Yang, Yuping; Harrington, Peter B.

    2015-12-01

    Terahertz time-domain spectroscopy (THz-TDS) has been utilized as an effective tool for quantitative analysis of imidacloprid in rice powder samples. Unlike previous studies, our method for sample preparation was mixing imidacloprid with rice powder instead of polyethylene. Then, terahertz time domain transmission spectra of these mixed samples were measured and the absorption coefficient spectra of the samples with frequency range extending from 0.3 to 1.7 THz were obtained. Asymmetric least square (AsLS) method was utilized to correct the slope baselines that are presented in THz absorption coefficient spectra and improve signal-to-noise ratio of THz spectra. Chemometrics methods, including partial least squares (PLS), support vector regression (SVR), interval partial least squares (iPLS), and backward interval partial least squares (biPLS), were used for quantitative model building and prediction. To achieve a reliable and unbiased estimation, bootstrapped Latin partition was chosen as an approach for statistical cross-validation. Results showed that the mean value of root mean square error of prediction (RMSEP) for PLS (0.5%) is smaller than SVR (0.7%), these two methods were based on the whole absorption coefficient spectra. In addition, PLS performed a better performance with a lower RMSEP (0.3%) based on the THz absorption coefficient spectra after AsLS baseline correction. Alternatively, two methods for variable selection, namely iPLS and biPLS, yielded models with improved predictions. Comparing with conventional PLS and SVR, the mean values of RMSEP were 0.4% (iPLS) and 0.3% (biPLS) by selecting the informative frequency ranges. The results demonstrated that an accurate quantitative analysis of imidacloprid in rice powder samples could be achieved by terahertz time-domain transmission spectroscopy combined with chemometrics. Furthermore, these results demonstrate that THz time-domain spectroscopy can be used for quantitative determinations of other pesticides in other agricultural products.

  10. Light Scattering and Absorption Spectroscopy in Three Dimensions Using Quantitative Low Coherence Interferometry for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Robles, Francisco E.

    The behavior of light after interacting with a biological medium reveals a wealth of information that may be used to distinguish between normal and disease states. This may be achieved by simply imaging the morphology of tissues or individual cells, and/or by more sophisticated methods that quantify specific surrogate biomarkers of disease. To this end, the work presented in this dissertation demonstrates novel tools derived from low coherence interferometry (LCI) that quantitatively measure wavelength-dependent scattering and absorption properties of biological samples, with high spectral resolution and micrometer spatial resolution, to provide insight into disease states. The presented work first describes a dual window (DW) method, which decomposes a signal sampled in a single domain (in this case the frequency domain) to a distribution that simultaneously contains information from both the original domain and the conjugate domain (here, the temporal or spatial domain). As the name suggests, the DW method utilizes two independently adjustable windows, each with different spatial and spectral properties to overcome limitations found in other processing methods that seek to obtain the same information. A theoretical treatment is provided, and the method is validated through simulations and experiments. With this tool, the spatially dependent spectral behavior of light after interacting with a biological medium may be analyzed to extract parameters of interest, such as the scattering and absorption properties. The DW method is employed to investigate scattering properties of samples using Fourier domain LCI (fLCI). In this method, induced temporal coherence effects provide insight into structural changes in dominant scatterers, such as cell nuclei within tissue, which can reveal the early stages of cancerous development. fLCI is demonstrated in complex, three-dimensional samples using a scattering phantom and an ex-vivo animal model. The results from the latter study show that fLCI is able to detect changes in the morphology of tissues undergoing precancerous development. The DW method is also employed to enable a novel form of optical coherence tomography (OCT), an imaging modality that uses coherence gating to obtain micrometer-scale, cross-sectional information of tissues. The novel method, named molecular imaging true color spectroscopic OCT (METRiCS OCT), analyses the depth dependent absorption of light to ascertain quantitative information of chromophore concentration, such as hemoglobin. The molecular information is also processed to yield a true color representation of the sample, a unique capability of this approach. A number of experiments, including hemoglobin absorbing phantoms and in-vivo imaging of a chick embryo model and dorsal skinfold window chamber model, demonstrate the power of the method. The final method presented in this dissertation, consists of a spectroscopic approach that interrogates the dispersive biochemical properties of samples to independently probe the scattering and absorption coefficients. To demonstrate this method, named non-linear phase dispersion spectroscopy (NLDS), a careful analysis of LCI signals is presented. The method is verified using measurements from samples that scatter and absorb light. Lastly, NLDS is combined with phase microscopy to achieve molecular imaging with sub-micron spatial resolution. Imaging of red blood cells (RBCs) shows that the method enables highly sensitive measurements that can quantify hemoglobin content from single RBCs.

  11. [Near infrared spectroscopy quantitative analysis model based on incremental neural network with partial least squares].

    PubMed

    Cao, Hui; Li, Da-Hang; Liu, Ling; Zhou, Yan

    2014-10-01

    This paper proposes an near infrared spectroscopy quantitative analysis model based on incremental neural network with partial least squares. The proposed model adopts the typical three-layer back-propagation neural network (BPNN), and the absorbance of different wavelengths and the component concentration are the inputs and the outputs, respectively. Partial least square (PLS) regression is performed on the history training samples firstly, and the obtained history loading matrices of the in- dependent variables and the dependent variables are used for determining the initial weights of the input layer and the output lay- er, respectively. The number of the hidden layer nodes is set as the number of the principal components of the independent varia- bles. After a set of new training samples is collected, PLS regression is performed on the combination dataset consisting of the new samples and the history loading matrices to calculate the new loading matrices. The history loading matrices and the new loading matrices are fused to obtain the new initial weights of the input layer and the output layer of the proposed model. Then the new samples are used for training the proposed mode to realize the incremental update. The proposed model is compared with PLS, BPNN, the BPNN based on PLS (PLS-BPNN) and the recursive PLS (RPLS) by using the spectra data of flue gas of nat- ural gas combustion. For the concentration prediction of the carbon dioxide in the flue gas, the root mean square error of predic- tion (RMSEP) of the proposed model are reduced by 27.27%, 58.12%, 19.24% and 14.26% than those of PLS, BPNN, PLS- BPNN and RPLS, respectively. For the concentration prediction of the carbon monoxide in the flue gas, the RMSEP of the pro- posed model are reduced by 20.65%, 24.69%, 18.54% and 19.42% than those of PLS, BPNN, PLS-BPNN and RPLS, re- spectively. For the concentration prediction of the methane in the flue gas, the RMSEP of the proposed model are reduced by 27.56%, 37.76%, 8.63% and 3.20% than those of PLS, BPNN, PLS-BPNN and RPLS, respectively. Experiments results show that the proposed model could optimize the construction and the initial weights of BPNN by PLS and has higher prediction effectiveness. Moreover, based on the information of the built model, the proposed model uses the new samples for incremental update without accessing the history samples. Hence, the proposed model has better robustness and generalization. PMID:25739228

  12. A quantitative study for determination of sugar concentration using attenuated total reflectance terahertz (ATR-THz) spectroscopy

    NASA Astrophysics Data System (ADS)

    Suhandy, Diding; Suzuki, Tetsuhito; Ogawa, Yuichi; Kondo, Naoshi; Ishihara, Takeshi; Takemoto, Yuichiro

    2011-06-01

    The objective of our research was to use ATR-THz spectroscopy together with chemometric for quantitative study in food analysis. Glucose, fructose and sucrose are main component of sugar both in fresh and processed fruits. The use of spectroscopic-based method for sugar determination is well reported especially using visible, near infrared (NIR) and middle infrared (MIR) spectroscopy. However, the use of terahertz spectroscopy for sugar determination in fruits has not yet been reported. In this work, a quantitative study for sugars determination using attenuated total reflectance terahertz (ATR-THz) spectroscopy was conducted. Each samples of glucose, fructose and sucrose solution with different concentrations were prepared respectively and their absorbance spectra between wavenumber 20 and 450 cm-1 (between 0.6 THz and 13.5 THz) were acquired using a terahertz-based Fourier Transform spectrometer (FARIS-1S, JASCO Co., Japan). This spectrometer was equipped with a high pressure of mercury lamp as light source and a pyroelectric sensor made from deuterated L-alanine triglycine sulfate (DLTGS) as detector. Each spectrum was acquired using 16 cm-1 of resolution and 200 scans for averaging. The spectra of water and sugar solutions were compared and discussed. The results showed that increasing sugar concentration caused decreasing absorbance. The correlation between sugar concentration and its spectra was investigated using multivariate analysis. Calibration models for glucose, fructose and sucrose determination were developed using partial least squares (PLS) regression. The calibration model was evaluated using some parameters such as coefficient of determination (R2), standard error of calibration (SEC), standard error of prediction (SEP), bias between actual and predicted sugar concentration value and ratio prediction to deviation (RPD) parameter. The cross validation method was used to validate each calibration model. It is showed that the use of ATR-THz spectroscopy combined with appropriate chemometric can be a potential for a rapid determination of sugar concentrations.

  13. Near- and Mid-Infrared Reflectance Spectroscopy for the Quantitative and Qualitative Analysis of Agricultural Products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For several decades near-infrared diffuse reflectance spectroscopy (NIRS) has been used to determine the composition of a variety of agricultural products. More recently, diffuse reflectance Fourier transform mid-infrared spectroscopy (DRIFTS) has similarly been shown to be able to determine the co...

  14. Advanced calibration strategy for in situ quantitative monitoring of phase transition processes in suspensions using FT-Raman spectroscopy.

    PubMed

    Chen, Zeng-Ping; Fevotte, Gilles; Caillet, Alexandre; Littlejohn, David; Morris, Julian

    2008-09-01

    There is an increasing interest in using Raman spectroscopy to identify polymorphic forms and monitor phase changes in pharmaceutical products for quality control. Compared with other analytical techniques for the identification of polymorphs such as X-ray powder diffractometry and infrared spectroscopy, FT-Raman spectroscopy has the advantages of enabling fast, in situ, and nondestructive measurements of complex systems such as suspension samples. However, for suspension samples, Raman intensities depend on the analyte concentrations as well as the particle size, overall solid content, and homogeneity of the solid phase in the mixtures, which makes quantitative Raman analysis rather difficult. In this contribution, an advanced model has been derived to explicitly account for the confounding effects of a sample's physical properties on Raman intensities. On the basis of this model, a unique calibration strategy called multiplicative effects correction (MEC) was proposed to separate the Raman contributions due to changes in analyte concentration from those caused by the multiplicative confounding effects of the sample's physical properties. MEC has been applied to predict the anhydrate concentrations from in situ FT-Raman measurements made during the crystallization and phase transition processes of citric acid in water. The experimental results show that MEC can effectively correct for the confounding effects of the particle size and overall solid content of the solid phase on Raman intensities and, therefore, provide much more accurate in situ quantitative predictions of anhydrate concentration during crystallization and phase transition processes than traditional PLS calibration methods. PMID:18665607

  15. Ultrasound-assisted ionic liquid-based dispersive liquid-liquid microextraction for preconcentration of patent blue V and its determination in food samples by UV-visible spectrophotometry.

    PubMed

    Unsal, Yunus Emre; Soylak, Mustafa; Tuzen, Mustafa

    2015-04-01

    Ultrasound-assisted ionic liquid-based dispersive liquid-liquid microextraction procedure (UA-IL-DLLME) was developed for determination of trace levels of patent blue V prior to its determination by UV-visible spectrophotometry. Patent blue V was extracted from 25-mL sample into a 100-?L volume of ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), with the aid of sonication in an ultrasonic bath. Several variables affecting microextraction efficiency were optimized. Under the optimum experimental conditions, the detection limit (3 s) was 0.68 ?g L(-1), and the preconcentration factor was 100. The relative standard deviation for six replicate determinations of patent blue V was 4.5%. The method was applied to the determination of patent blue V in food samples. The proposed procedure is effective, very simple, and fast. PMID:25800367

  16. Quantitative spectroscopy of hot stars: accurate atomic data applied on a large scale as driver of recent breakthroughs

    NASA Astrophysics Data System (ADS)

    Przybilla, Norbert; Schaffenroth, Veronika; Nieva, Maria-Fernanda

    2015-08-01

    OB-type stars present hotbeds for non-LTE physics because of their strong radiation fields that drive the atmospheric plasma out of local thermodynamic equilibrium. We report on recent breakthroughs in the quantitative analysis of the optical and UV-spectra of OB-type stars that were facilitated by application of accurate and precise atomic data on a large scale. An astophysicist's dream has come true, by bringing observed and model spectra into close match over wide parts of the observed wavelength ranges. This facilitates tight observational constraints to be derived from OB-type stars for wide applications in astrophysics. However, despite the progress made, many details of the modelling may be improved further. We discuss atomic data needs in terms of laboratory measurements and also ab-initio calculations. Particular emphasis is given to quantitative spectroscopy in the near-IR, which will be in focus in the era of the upcoming extremely large telescopes.

  17. Semi-quantitative surface analysis of Mt. St. Helens Ash by X-ray photoelectron spectroscopy (XPS)

    NASA Astrophysics Data System (ADS)

    Brown, J. R.; Fyfe, W. S.; Bancroft, G. M.

    A sample of Mt. St. Helens tephra and USGS andesite rock standard (AGV-1) were analyzed by X-ray photoelectron spectroscopy (XPS). The results indicate major element surface analysis on powdered multicomponent samples (such as geological specimens) can be performed semi-quantitatively using an equation that relates XPS peak intensity with atomic surface density. The surface compositions found by XPS are in good agreement with bulk X-ray fluorescence analysis (XRF). It is interesting to note that XPS analysis of this volcanic ash did not reveal a surface enrichment of chlorine or sulphur and only trace fluorine although these volatile elements are normally abundant in volcanic gases.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  19. Quantitative analysis of routine chemical constituents in tobacco by near-infrared spectroscopy and support vector machine

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Cong, Qian; Xie, Yunfei; Yang, Jingxiu; Zhao, Bing

    2008-12-01

    It is important to monitor quality of tobacco during the production of cigarette. Therefore, in order to scientifically control the tobacco raw material and guarantee the cigarette quality, fast and accurate determination routine chemical of constituents of tobacco, including the total sugar, reducing sugar, Nicotine, the total nitrogen and so on, is needed. In this study, 50 samples of tobacco from different cultivation areas were surveyed by near-infrared (NIR) spectroscopy, and the spectral differences provided enough quantitative analysis information for the tobacco. Partial least squares regression (PLSR), artificial neural network (ANN), and support vector machine (SVM), were applied. The quantitative analysis models of 50 tobacco samples were studied comparatively in this experiment using PLSR, ANN, radial basis function (RBF) SVM regression, and the parameters of the models were also discussed. The spectrum variables of 50 samples had been compressed through the wavelet transformation technology before the models were established. The best experimental results were obtained using the (RBF) SVM regression with ? = 1.5, 1.3, 0.9, and 0.1, separately corresponds to total sugar, reducing sugar, Nicotine, and total nitrogen, respectively. Finally, compared with the back propagation (BP-ANN) and PLSR approach, SVM algorithm showed its excellent generalization for quantitative analysis results, while the number of samples for establishing the model is smaller. The overall results show that NIR spectroscopy combined with SVM can be efficiently utilized for rapid and accurate analysis of routine chemical compositions in tobacco. Simultaneously, the research can serve as the technical support and the foundation of quantitative analysis of other NIR applications.

  20. Quantitative Raman Spectroscopy to monitor microbial metabolism in situ under pressure

    NASA Astrophysics Data System (ADS)

    Picard, A.; Daniel, I.; Oger, P.

    2006-12-01

    Although high hydrostatic pressure (HHP) biotopes are ubiquitous on Earth, little is known about the metabolism of piezophile organisms. Cell culture under HHP can be technically challenging, and equipment- dependent. In addition, the depressurization step required for analysis can lead to erroneous data. Therefore, to understand how piezophile organisms react to pressure, it is crucial to be able to monitor their activity in situ under HHP. We developed the use of Quantitative Raman Spectroscopy (QRS, 1) to monitor in situ the metabolism of organic molecules. This technique is based on the specific spectral signature of an analyte from which its concentration can be deduced. An application of this technique to the monitoring of alcoholic fermentation by the piezotolerant micro-eucaryote Saccharomyces cerevisiae is presented. Ethanol fermentation from glucose was monitored during 24h from ambient P up to 100 MPa in the low- pressure Diamond Anvil Cell (lpDAC, 2). The experimental compression chamber consisted in a 300 ?m-thick Ni gasket in which a 500 ?m-diameter hole was drilled. Early-stationnary yeast cells were inoculated into fresh low-fluorescence medium containing 0.15 M of glucose. Ethanol concentration was determined in situ by QRS using the symmetric C-C stretching mode of ethanol at 878 cm-1 normalizing the data to the intensity of the sulfate S-O stretching mode at 980 cm-1. In our setup, the detection limit of ethanol is lower than 0.05 mM with a precision below 1%. At ambient P, ethanol production in the lpDAC and in control experiments proceeds with the same kinetics. Thus, yeast is not affected by its confinement. This is further confirmed by its ability to bud with a generation time similar to control experiments performed in glass tubes at ambient pressure inside the lpDAC. Ethanol production by yeast occurs to at least 65 MPa (3). At 10 MPa, fermentation proceeds 3 times faster than at ambient P. Fermentation rates decrease linearly from 20 to at least 65 MPa. No ethanol was detected at 100 MPa. From these data, the pressure at which ethanol fermentation stops in yeast was calculated to be 87±7 MPa. These results indicate that the activity of one or several enzymes of the glycolytic pathway is enhanced at low pressure. At higher pressure, they become progressively repressed, and are completely inhibited above 87 MPa. Our in situ monitoring constitutes a direct demonstration of yeast metabolism in situ under pressure up to 100 MPa. Our data agree with previous ex-situ data by Abe and Horikoshi (4). However, we observed that ethanol production is not completely inhibited around 50 MPa as predicted, but could be detected at significantly higher pressures (up to 87 MPa). QSR is a powerful method to monitor microbial activities, since almost any organic molecule with a carbon chain ranging from 1 to 6 carbon can be detected and quantified. The only limitation of QSR is that the Raman spectrum of the molecule exhibits at least one peak not masked by the spectrum of the growth medium. 1 Pelletier M J Appl Spectr 57:20A-42A, 2003 2 Daniel I, Oger P, Picard A, Cardon H and Chervin J-C (submitted to Rev Sci Instr) 3 Picard A, Daniel I, Montagnac G and Oger P (submitted to Extremophiles) 4 Abe F and Horikoshi K Extremophiles 1: 89-93, 1997

  1. Separation and Preconcentration of Sudan Blue II Using Membrane Filtration and UV-Visible Spectrophotometric Determination in River Water and Industrial Wastewater Samples.

    PubMed

    Unsal, Yunus Emre; Tuzen, Mustafa; Soylak, Mustafa

    2015-01-01

    A new separation and preconcentration method based on adsorption on a cellulose acetate membrane filter and elution with ethanol was established for the UV-Vis spectrophotometric determination of Sudan blue II. Various analytical parameters such as pH of working media, flow rates of solutions, and sample volumes were optimized. Matrix effects of concomitants were investigated for the quantitative recovery values of Sudan blue II. The preconcentration factor was 200. LOD was calculated as 0.96 ?g/L. RSD was 5.1%. The optimized procedure was applied to the spectrophotometric determination of Sudan blue II in river and industrial wastewater samples from oil and dye products. PMID:25857900

  2. Real time quantitative Raman spectroscopy of supported metal oxide catalysts without the need of an internal standard.

    PubMed

    Tinnemans, S J; Kox, M H F; Nijhuis, T A; Visser, T; Weckhuysen, B M

    2005-01-01

    In continuation to the possibility of using a combined operando Raman/UV-Vis-NIR set-up for conducting qualitative Raman spectroscopy, the possibilities for quantitative Raman spectroscopic measurements of supported metal oxide catalysts under working conditions without the need of an internal standard have been explored. The dehydrogenation of propane over an industrial-like 13 wt% Cr/Al203 catalyst was used as a model system. During reaction, the catalytic solid was continuously monitored by both UV-Vis-NIR and Raman spectroscopy. As the dehydrogenation proceeds, the catalyst gradually darkens due to coke formation and consequently the UV-Vis-NIR diffuse reflectance and Raman scattered signal progressively decrease in intensity. The formation of coke was confirmed with TEOM, TGA and Raman. The measured Raman spectra can be used as a quantitative measure of the amount of carbonaceous deposits at the catalyst surface provided that a correction factor G(R(infinity)) is applied. This factor can be directly calculated from the corresponding UV-Vis-NIR diffuse reflectance spectra. The validity of the approach is compared with one, in which an internal boron nitride standard is added to the catalytic solid. It will be shown that the proposed methodology allows measurement of the amount of carbonaceous deposits on a catalyst material inside a reactor as a function of reaction time and catalyst bed height. As a consequence, an elegant technique for on-line process control of e.g. an industrial propane dehydrogenation reactor emerges. PMID:19785192

  3. Quantitative Raman spectroscopy as a tool to study the kinetics and formation mechanism of carbonates.

    PubMed

    Bonales, L J; Muñoz-Iglesias, V; Santamaría-Pérez, D; Caceres, M; Fernandez-Remolar, D; Prieto-Ballesteros, O

    2013-12-01

    We have carried out a systematic study of abiotic precipitation at different temperatures of several Mg and Ca carbonates (calcite, nesquehonite, hydrocalcite) present in carbonaceous chondrites. This study highlights the capability of Raman spectroscopy as a primary tool for performing full mineralogical analysis. The precipitation reaction and the structure of the resulting carbonates were monitored and identified with Raman spectroscopy. Raman spectroscopy enabled us to confirm that the precipitation reaction is very fast (minutes) when Ca(II) is present in the solution, whereas for Mg(II) such reactions developed at rather slow rates (weeks). We also observed that both the composition and the reaction mechanisms depended on temperature, which might help to clarify several issues in the fields of planetology and geology, because of the environmental implications of these carbonates on both terrestrial and extraterrestrial objects. PMID:23896294

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

    PubMed

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

    2010-05-01

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

  5. QUANTITATIVE ULTRAVIOLET SPECTROSCOPY IN WEATHERING OF A MODEL POLYESTER-URETHANE COATING. (R828081E01)

    EPA Science Inventory

    Spectroscopy was used to quantify the effects of ultraviolet light on a model polyester–urethane coating as it degraded in an accelerated exposure chamber. An explorative calculation of the effective dosage absorbed by the coatings was made and, depending on the quantum...

  6. Quantitative Orientation Measurements in Thin Lipid Films by Attenuated Total Reflection Infrared Spectroscopy

    E-print Network

    Pezolet, Michel

    Spectroscopy Fre´ de´ ric Picard,* Thierry Buffeteau,# Bernard Desbat,# Miche` le Auger,* and Michel Pe´ zolet technique has been used extensively to study proteins (Goormaghtigh et al., 1990), phospholipid multilayers., 1988), lipid-protein complexes (Okamura et al., 1986; Brauner et al., 1987; Cornell et al., 1989; Frey

  7. Rapid Quantitative Determination of Squalene in Shark Liver Oils by Raman and IR Spectroscopy.

    PubMed

    Hall, David W; Marshall, Susan N; Gordon, Keith C; Killeen, Daniel P

    2016-01-01

    Squalene is sourced predominantly from shark liver oils and to a lesser extent from plants such as olives. It is used for the production of surfactants, dyes, sunscreen, and cosmetics. The economic value of shark liver oil is directly related to the squalene content, which in turn is highly variable and species-dependent. Presented here is a validated gas chromatography-mass spectrometry analysis method for the quantitation of squalene in shark liver oils, with an accuracy of 99.0 %, precision of 0.23 % (standard deviation), and linearity of >0.999. The method has been used to measure the squalene concentration of 16 commercial shark liver oils. These reference squalene concentrations were related to infrared (IR) and Raman spectra of the same oils using partial least squares regression. The resultant models were suitable for the rapid quantitation of squalene in shark liver oils, with cross-validation r (2) values of >0.98 and root mean square errors of validation of ?4.3 % w/w. Independent test set validation of these models found mean absolute deviations of the 4.9 and 1.0 % w/w for the IR and Raman models, respectively. Both techniques were more accurate than results obtained by an industrial refractive index analysis method, which is used for rapid, cheap quantitation of squalene in shark liver oils. In particular, the Raman partial least squares regression was suited to quantitative squalene analysis. The intense and highly characteristic Raman bands of squalene made quantitative analysis possible irrespective of the lipid matrix. PMID:26620374

  8. Experimental and theoretical studies of (FT-IR, FT-Raman, UV-Visible and DFT) 4-(6-methoxynaphthalen-2-yl) butan-2-one.

    PubMed

    Govindasamy, P; Gunasekaran, S

    2015-10-01

    In this work, the vibrational spectral analysis was carried out by using FT-Raman and FT-IR spectroscopy in the range 4000-50 cm(-1) and 4000-450 cm(-1) respectively for 4-(6-methoxynaphthalen-2-yl) butan-2-one (abbreviated as 4MNBO) molecule. Theoretical calculations were performed by density functional theory (DFT/B3LYP) method using 6-311G(d,p) and 6-311++G(d,p) basis sets. The difference between the observed and calculated wavenumber value of most of the fundamentals were very small. The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution (PED). The UV-Vis spectrum was recorded in the methanol solution. The energy, wavelength and oscillator's strength were calculated by Time Dependent Density Functional Theory (TD-DFT) and matched to the experimental findings. The intramolecular contacts have been interpreted using natural bond orbital (NBO) and natural localized molecular orbital (NLMO) analysis. Thermodynamic properties of 4MNBO at different temperature have been calculated. The molecular electrostatic potential surface (MESP) and Frontier molecular orbital's (FMO's) analysis were investigated using theoretical calculations. PMID:25997177

  9. Spectral simulation methods for enhancing qualitative and quantitative analyses based on infrared spectroscopy and quantitative calibration methods for passive infrared remote sensing of volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Sulub, Yusuf Ismail

    Infrared spectroscopy (IR) has over the years found a myriad of applications including passive environmental remote sensing of toxic pollutants and the development of a blood glucose sensor. In this dissertation, capabilities of both these applications are further enhanced with data analysis strategies employing digital signal processing and novel simulation approaches. Both quantitative and qualitative determinations of volatile organic compounds are investigated in the passive IR remote sensing research described in this dissertation. In the quantitative work, partial least-squares (PLS) regression analysis is used to generate multivariate calibration models for passive Fourier transform IR remote sensing measurements of open-air generated vapors of ethanol in the presence methanol as an interfering species. A step-wise co-addition scheme coupled with a digital filtering approach is used to attenuate the effects of variation in optical path length or plume width. For the qualitative study, an IR imaging line scanner is used to acquire remote sensing data in both spatial and spectral domains. This technology is capable of not only identifying but also specifying the location of the sample under investigation. Successful implementation of this methodology is hampered by the huge costs incurred to conduct these experiments and the impracticality of acquiring large amounts of representative training data. To address this problem, a novel simulation approach is developed that generates training data based on synthetic analyte-active and measured analyte-inactive data. Subsequently, automated pattern classifiers are generated using piecewise linear discriminant analysis to predict the presence of the analyte signature in measured imaging data acquired in remote sensing applications. Near infrared glucose determinations based on the region of 5000--4000 cm-1 is the focus of the research in the latter part of this dissertation. A six-component aqueous matrix of glucose in the presence of five other interferent species, all spanning physiological levels, is analyzed quantitatively. Multivariate PLS regression analysis in conjunction with samples designated into a calibration set is used to formulate models for predicting glucose concentrations. Variations in the instrumental response caused by drift and environmental factors are observed to degrade the performance of these models. As a remedy, a model updating approach based on spectral simulation is developed that is highly successful in eliminating the adverse effects of non-chemical variations.

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

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

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

  11. An improved method for quantitative determination of urinary porphyrins by use of second-derivative spectroscopy.

    PubMed

    van de Giessen, A W; van Wijk, E M

    1990-09-01

    An improved assay for quantification of urinary porphyrins by use of second-derivative spectroscopy is described. A new method for calculation of the porphyrin concentration is developed and the whole procedure is computerized. Acidified urine samples can be assayed within a few minutes by using this method. Precision and recoveries for both uro- and coproporphyrin are good. The method is presented as a very fast and accurate assay for the screening and quantification of urinary porphyrins. PMID:2290079

  12. Analysis of OBrO, IO, and OIO absorption signature in UV-visible spectra measured at night and at sunrise by stratospheric balloon-borne instruments

    NASA Astrophysics Data System (ADS)

    Berthet, GwenaëL.; Renard, Jean-Baptiste; Chartier, Michel; Pirre, Michel; Robert, Claude

    2003-03-01

    Absorption bands of OBrO, IO, and OIO in the visible region have been investigated in the data of the AMON ("Absorption par les Minoritaires Ozone et Nox") and SALOMON ("Spectroscopie d'Absorption Lunaire pour l'Observation des Minoritaires Ozone et Nox") balloon-borne spectrometers used to obtain measurements in the nighttime stratosphere, since 1992 and 1998 respectively. The absorption features initially detected in AMON residual spectra and attributed to OBrO are also observable in SALOMON data with better accuracy. New estimates of OBrO cross-section amplitudes taking into account recent laboratory measurements are used for the OBrO retrieval. A consequence is that previously published OBrO concentration and mixing ratio values are revised downwards of around 40%. Further tests are performed to assess the consistency of the OBrO detection. No correlation exists between OBrO and NO2 vertical profiles which practically rules out the possibility for the structures ascribed to OBrO absorption to be due to remaining NO2 contributions. It is shown that variability of OBrO quantities at high latitudes obtained from various AMON and SALOMON flights is possibly linked to the chemical processes involving the production of OClO. At midlatitudes, the exceptional and unexpected conditions of the April 28, 1999 SALOMON flight allow us to observe the drop in OBrO concentrations just after sunrise. As expected, if previous studies of stratospheric iodine species are considered, IO and OIO absorption lines are never detected in the residual spectra. The presence of unknown structures in the residual spectra in the IO and OIO absorption regions is obvious and tends to distort the retrievals. The possibility that these remaining features result from a temperature dependence effect or uncertainties of O3 and/or NO2 cross-sections is suggested. Thus, more accurate laboratory measurements and sets of cross-sections for low temperature are needed.

  13. Infrared spectroscopy reveals both qualitative and quantitative differences in equine subchondral bone during maturation

    NASA Astrophysics Data System (ADS)

    Kobrina, Yevgeniya; Isaksson, Hanna; Sinisaari, Miikka; Rieppo, Lassi; Brama, Pieter A.; van Weeren, René; Helminen, Heikki J.; Jurvelin, Jukka S.; Saarakkala, Simo

    2010-11-01

    The collagen phase in bone is known to undergo major changes during growth and maturation. The objective of this study is to clarify whether Fourier transform infrared (FTIR) microspectroscopy, coupled with cluster analysis, can detect quantitative and qualitative changes in the collagen matrix of subchondral bone in horses during maturation and growth. Equine subchondral bone samples (n = 29) from the proximal joint surface of the first phalanx are prepared from two sites subjected to different loading conditions. Three age groups are studied: newborn (0 days old), immature (5 to 11 months old), and adult (6 to 10 years old) horses. Spatial collagen content and collagen cross-link ratio are quantified from the spectra. Additionally, normalized second derivative spectra of samples are clustered using the k-means clustering algorithm. In quantitative analysis, collagen content in the subchondral bone increases rapidly between the newborn and immature horses. The collagen cross-link ratio increases significantly with age. In qualitative analysis, clustering is able to separate newborn and adult samples into two different groups. The immature samples display some nonhomogeneity. In conclusion, this is the first study showing that FTIR spectral imaging combined with clustering techniques can detect quantitative and qualitative changes in the collagen matrix of subchondral bone during growth and maturation.

  14. Accurate determination of reference materials and natural isolates by means of quantitative (1)h NMR spectroscopy.

    PubMed

    Frank, Oliver; Kreissl, Johanna Karoline; Daschner, Andreas; Hofmann, Thomas

    2014-03-26

    A fast and precise proton nuclear magnetic resonance (qHNMR) method for the quantitative determination of low molecular weight target molecules in reference materials and natural isolates has been validated using ERETIC 2 (Electronic REference To access In vivo Concentrations) based on the PULCON (PULse length based CONcentration determination) methodology and compared to the gravimetric results. Using an Avance III NMR spectrometer (400 MHz) equipped with a broad band observe (BBO) probe, the qHNMR method was validated by determining its linearity, range, precision, and accuracy as well as robustness and limit of quantitation. The linearity of the method was assessed by measuring samples of l-tyrosine, caffeine, or benzoic acid in a concentration range between 0.3 and 16.5 mmol/L (r(2) ? 0.99), whereas the interday and intraday precisions were found to be ?2%. The recovery of a range of reference compounds was ?98.5%, thus demonstrating the qHNMR method as a precise tool for the rapid quantitation (~15 min) of food-related target compounds in reference materials and natural isolates such as nucleotides, polyphenols, or cyclic peptides. PMID:24559241

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

    PubMed

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

    2015-05-01

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

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

    SciTech Connect

    Shao Yongni; He Yong; Mao Jingyuan

    2007-09-01

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

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

    PubMed Central

    Lau, Peter C.Y.; Dutcher, John R.; Beveridge, Terry J.; Lam, Joseph S.

    2009-01-01

    Bacterial biofilms are the most prevalent mode of bacterial growth in nature. Adhesive and viscoelastic properties of bacteria play important roles at different stages of biofilm development. Following irreversible attachment of bacterial cells onto a surface, a biofilm can grow in which its matrix viscoelasticity helps to maintain structural integrity, determine stress resistance, and control ease of dispersion. In this study, a novel application of force spectroscopy was developed to characterize the surface adhesion and viscoelasticity of bacterial cells in biofilms. By performing microbead force spectroscopy with a closed-loop atomic force microscope, we accurately quantified these properties over a defined contact area. Using the model gram-negative bacterium Pseudomonas aeruginosa, we observed that the adhesive and viscoelastic properties of an isogenic lipopolysaccharide mutant wapR biofilm were significantly different from those measured for the wild-type strain PAO1 biofilm. Moreover, biofilm maturation in either strain also led to prominent changes in adhesion and viscoelasticity. To minimize variability in force measurements resulting from experimental parameter changes, we developed standardized conditions for microbead force spectroscopy to enable meaningful comparison of data obtained in different experiments. Force plots measured under standard conditions showed that the adhesive pressures of PAO1 and wapR early biofilms were 34 ± 15 Pa and 332 ± 47 Pa, respectively, whereas those of PAO1 and wapR mature biofilms were 19 ± 7 Pa and 80 ± 22 Pa, respectively. Fitting of creep data to a Voigt Standard Linear Solid viscoelasticity model revealed that the instantaneous and delayed elastic moduli in P. aeruginosa were drastically reduced by lipopolysaccharide deficiency and biofilm maturation, whereas viscosity was decreased only for biofilm maturation. In conclusion, we have introduced a direct biophysical method for simultaneously quantifying adhesion and viscoelasticity in bacterial biofilms under native conditions. This method could prove valuable for elucidating the contribution of genetic backgrounds, growth conditions, and environmental stresses to microbial community physiology. PMID:19348775

  18. Domain Dynamics in Piezoresponse Force Spectroscopy: Quantitative Deconvolution and Hysteresis Loop Fine Structure

    SciTech Connect

    Bdikin, Igor; Kholkin, Andrei; Morozovska, A. N.; Svechnikov, S. V.; Kim, S.-H.; Kalinin, Sergei V

    2008-01-01

    Domain dynamics in the Piezoresponse Force Spectroscopy (PFS) experiment is studied using the combination of local hysteresis loop acquisition with simultaneous domain imaging. The analytical theory for PFS signal from domain of arbitrary cross-section and length is developed for the analysis of experimental data on Pb(Zr,Ti)O3 polycrystalline films. The results suggest formation of oblate domain at early stage of the nucleation and growth, consistent with efficient screening of depolarization field. The fine structure of the hysteresis loop is shown to be related to the observed jumps in the domain geometry during domain wall propagation (nanoscale Barkhausen jumps), indicative of strong domain-defect interactions.

  19. Qualitative and Quantitative Control of Carbonated Cola Beverages Using 1H NMR Spectroscopy

    PubMed Central

    2012-01-01

    1H Nuclear magnetic resonance (NMR) spectroscopy (400 MHz) was used in the context of food surveillance to develop a reliable analytical tool to differentiate brands of cola beverages and to quantify selected constituents of the soft drinks. The preparation of the samples required only degassing and addition of 0.1% of TSP in D2O for locking and referencing followed by adjustment of pH to 4.5. The NMR spectra obtained can be considered as “fingerprints” and were analyzed by principal component analysis (PCA). Clusters from colas of the same brand were observed, and significant differences between premium and discount brands were found. The quantification of caffeine, acesulfame-K, aspartame, cyclamate, benzoate, hydroxymethylfurfural (HMF), sulfite ammonia caramel (E 150D), and vanillin was simultaneously possible using external calibration curves and applying TSP as internal standard. Limits of detection for caffeine, aspartame, acesulfame-K, and benzoate were 1.7, 3.5, 0.8, and 1.0 mg/L, respectively. Hence, NMR spectroscopy combined with chemometrics is an efficient tool for simultaneous identification of soft drinks and quantification of selected constituents. PMID:22356160

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

    NASA Astrophysics Data System (ADS)

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

    2003-12-01

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

  1. Quantitative analysis of sulfathiazole polymorphs in ternary mixtures by attenuated total reflectance infrared, near-infrared and Raman spectroscopy.

    PubMed

    Hu, Yun; Erxleben, Andrea; Ryder, Alan G; McArdle, Patrick

    2010-11-01

    The simultaneous quantitative analysis of sulfathiazole polymorphs (forms I, III and V) in ternary mixtures by attenuated total reflectance-infrared (ATR-IR), near-infrared (NIR) and Raman spectroscopy combined with multivariate analysis is reported. To reduce the effect of systematic variations, four different data pre-processing methods; multiplicative scatter correction (MSC), standard normal variate (SNV), first and second derivatives, were applied and their performance was evaluated using their prediction errors. It was possible to derive a reliable calibration model for the three polymorphic forms, in powder ternary mixtures, using a partial least squares (PLS) algorithm with SNV pre-processing, which predicted the concentration of polymorphs I, III and V. Root mean square errors of prediction (RMSEP) for ATR-IR spectra were 5.0%, 5.1% and 4.5% for polymorphs I, III and V, respectively, while NIR spectra had a RMSEP of 2.0%, 2.9%, and 2.8% and Raman spectra had a RMSEP of 3.5%, 4.1%, and 3.6% for polymorphs I, III and V, respectively. NIR spectroscopy exhibits the smallest analytical error, higher accuracy and robustness. When these advantages are combined with the greater convenience of NIR's "in glass bottle" sampling method both ATR-IR and Raman methods appear less attractive. PMID:20605386

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  3. Quantitative analysis of D-(+)-glucose in fruit juices using diffusion ordered-1H nuclear magnetic resonance spectroscopy.

    PubMed

    Cao, Ruge; Komura, Fusae; Nonaka, Airi; Kato, Takeshi; Fukumashi, Junji; Matsui, Toshiro

    2014-01-01

    This study works on D-(+)-glucose quantitative analysis using diffusion ordered-quantitative (1)H nuclear magnetic resonance spectroscopy (DOSY-qNMR), by which an analyte could be distinguished from interferences based upon a characteristic diffusion coefficient (D) in gradient magnetic fields. The D value of D-(+)-glucose in deuterium oxide at 30°C was 5.6 × 10(-10) m(2)/s at a field gradient pulse of between 5.0 × 10(-2) and 3.0 × 10(-1) T/m, distinguished from fructose, sucrose and starch. Good linearity (r(2) = 0.9998) was obtained between D-(+)-glucose (0.5-20.0 g/L) and the ratio of the resonance area of ?-C1 proton (5.21 ppm) in D-(+)-glucose to that of the ?-C1 proton (5.25 ppm) in D-glucuronic acid (50.0 g/L) as an internal standard. The DOSY-qNMR method was successfully applied to quantify D-(+)-glucose in orange juice (18.3 ± 1.0 g/L), apple juice (26.3 ± 0.4 g/L) and grape juice (45.6 ± 0.6 g/L); the values agreed well with a conventional F-kit glucose method. PMID:24614734

  4. Partial Least Squares and Neural Networks for Quantitative Calibration of Laser-induced Breakdown Spectroscopy (LIBs) of Geologic Samples

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    The ChemCam instrument [1] on the Mars Science Laboratory (MSL) rover will be used to obtain the chemical composition of surface targets within 7 m of the rover using Laser Induced Breakdown Spectroscopy (LIBS). ChemCam analyzes atomic emission spectra (240-800 nm) from a plasma created by a pulsed Nd:KGW 1067 nm laser. The LIBS spectra can be used in a semiquantitative way to rapidly classify targets (e.g., basalt, andesite, carbonate, sulfate, etc.) and in a quantitative way to estimate their major and minor element chemical compositions. Quantitative chemical analysis from LIBS spectra is complicated by a number of factors, including chemical matrix effects [2]. Recent work has shown promising results using multivariate techniques such as partial least squares (PLS) regression and artificial neural networks (ANN) to predict elemental abundances in samples [e.g. 2-6]. To develop, refine, and evaluate analysis schemes for LIBS spectra of geologic materials, we collected spectra of a diverse set of well-characterized natural geologic samples and are comparing the predictive abilities of PLS, cascade correlation ANN (CC-ANN) and multilayer perceptron ANN (MLP-ANN) analysis procedures.

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

    SciTech Connect

    Mukherjee, Dibyendu; Cheng, Mengdawn

    2008-01-01

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

  6. Quantitative analysis of mebendazole polymorphs in pharmaceutical raw materials using near-infrared spectroscopy.

    PubMed

    da Silva, Vitor H; Gonçalves, Jacqueline L; Vasconcelos, Fernanda V C; Pimentel, M Fernanda; Pereira, Claudete F

    2015-11-10

    This work evaluates the feasibility of using NIR spectroscopy for quantification of three polymorphs of mebendazole (MBZ) in pharmaceutical raw materials. Thirty ternary mixtures of polymorphic forms of MBZ were prepared, varying the content of forms A and C from 0 to 100% (w/w), and for form B from 0 to 30% (w/w). Reflectance NIR spectra were used to develop partial least square (PLS) regression models using all spectral variables and the variables with significant regression coefficients selected by the Jack-Knife algorithm (PLS/JK). MBZ polymorphs were quantified with RMSEP values of 2.37% w/w, 1.23% w/w and 1.48% w/w for polymorphs A, B and C, respectively. This is an easy, fast and feasible method for monitoring the quality of raw pharmaceutical materials of MBZ according to polymorph purity. PMID:26320077

  7. Quantitative Analysis of Microbicide Concentrations in Fluids, Gels and Tissues Using Confocal Raman Spectroscopy

    PubMed Central

    Chuchuen, Oranat; Henderson, Marcus H.; Sykes, Craig; Kim, Min Sung; Kashuba, Angela D. M.; Katz, David F.

    2013-01-01

    Topical vaginal anti-HIV microbicides are an important focus in female-based strategies to prevent the sexual transmission of HIV. Understanding microbicide pharmacokinetics is essential to development, characterization and implementation of efficacious microbicide drug delivery formulations. Current methods to measure drug concentrations in tissue (e.g., LC-MS/MS, liquid chromatography coupled with tandem mass spectrometry) are highly sensitive, but destructive and complex. This project explored the use of confocal Raman spectroscopy to detect microbicide drugs and to measure their local concentrations in fluids, drug delivery gels, and tissues. We evaluated three candidate microbicide drugs: tenofovir, Dapivirine and IQP-0528. Measurements were performed in freshly excised porcine buccal tissue specimens, gel vehicles and fluids using two Horiba Raman microscopes, one of which is confocal. Characteristic spectral peak calibrations for each drug were obtained using serial dilutions in the three matrices. These specific Raman bands demonstrated strong linear concentration dependences in the matrices and were characterized with respect to their unique vibrational signatures. At least one specific Raman feature was identified for each drug as a marker band for detection in tissue. Sensitivity of detection was evaluated in the three matrices. A specific peak was also identified for tenofovir diphosphate, the anti-HIV bioactive product of tenofovir after phosphorylation in host cells. Z-scans of drug concentrations vs. depth in excised tissue specimens, incubated under layers of tenofovir solution in a Transwell assay, showed decreasing concentration with depth from the surface into the tissue. Time-dependent concentration profiles were obtained from tissue samples incubated in the Transwell assay, for times ranging 30 minutes - 6 hours. Calibrations and measurements from tissue permeation studies for tenofovir showed good correlation with gold standard LC-MS/MS data. These results demonstrate that confocal Raman spectroscopy holds promise as a tool for practical, minimally invasive, label-free measurement of microbicide drug concentrations in fluids, gels and tissues. PMID:24386455

  8. Detection and quantitative determination of diethylene glycol in ethyl alcohol using gamma- ray spectroscopy.

    PubMed

    Udagani, Chikkappa; Ramesh, Thimmasandra Narayan

    2015-08-01

    Determination of the toxic diethylene glycol contamination in ethyl alcohol demands a rapid, accurate and reliable method. Diethylene glycol (DEG) ingestion, accidental or intentional, can lead to death. Clinical and analytical methods used to detect diethylene glycol in alcohol require several hours to days due to tedious instrument handling and measurements. Enzymatic assays face difficulty due to analytic problems. As an alternative method of data analysis, we have used ?-ray spectroscopic method to estimate the diethylene glycol contamination in alcohol by monitoring the variation in the linear and mass attenuation coefficients. This method is simple, robust, portable and can provide reliable and quantitative information about the ethyl alcohol adulterated with diethylene glycol which is of broader interest to society. PMID:26243958

  9. Quantitative degenerate four-wave mixing spectroscopy: Probes for molecular species

    SciTech Connect

    Farrow, R.; Rakestraw, D.; Paul, P.; Lucht, R.; Danehy, P.; Friedman-Hill, E.; Germann, G.

    1993-12-01

    Resonant degenerate four-wave mixing (DFWM) is currently the subject of intensive investigation as a sensitive diagnostic tool for molecular species. DFWM has the advantage of generating a coherent (beam-like) signal which results in null-background detection and provides excellent immunity to background-light interference. Since multiple one-photon resonances are involved in the signal generation process, the DFWM technique can allow sensitive detection of molecules via electronic, vibrational or rotational transitions. These properties combine to make DFWM a widely applicable diagnostic technique for the probing of molecular species. The authors are conducting fundamental and applied investigations of DFWM for quantitative measurements of trace species in reacting gases. During the past year, efforts have been focussed in two areas: (1) understanding the effects of collisional processes on the DFWM signal generation process, and (2) exploring the applicability of infrared DFWM to detect polyatomic molecules via rovibrational transitions.

  10. Quantitative analysis of cyclic dimer fatty acid content in the dimerization product by proton NMR spectroscopy.

    PubMed

    Park, Kyun Joo; Kim, Minyoung; Seok, Seunghwan; Kim, Young-Wun; Kim, Do Hyun

    2015-10-01

    In this work, (1)H NMR is utilized for the quantitative analysis of a specific cyclic dimer fatty acid in a dimer acid mixture using the pseudo-standard material of mesitylene on the basis of its structural similarity. Mesitylene and cyclic dimer acid levels were determined using the signal of the proton on the cyclic ring (?=6.8) referenced to the signal of maleic acid (?=6.2). The content of the cyclic dimer fatty acid was successfully determined through the standard curve of mesitylene and the reported equation. Using the linearity of the mesitylene curve, the cyclic dimer fatty acid in the oil mixture was quantified. The results suggest that the proposed method can be used to quantify cyclic compounds in mixtures to optimize the dimerization process. PMID:25974673

  11. Quantitative Analysis of Metabolic Mixtures by 2D 13C-Constant-Time TOCSY NMR Spectroscopy

    PubMed Central

    Bingol, Kerem; Zhang, Fengli; Bruschweiler-Li, Lei; Brüschweiler, Rafael

    2013-01-01

    An increasing number of organisms can be fully 13C-labeled, which has the advantage that their metabolomes can be studied by high-resolution 2D NMR 13C–13C constant-time (CT) TOCSY experiments. Individual metabolites can be identified via database searching or, in the case of novel compounds, through the reconstruction of their backbone-carbon topology. Determination of quantitative metabolite concentrations is another key task. Because significant peak overlaps in 1D NMR spectra prevents straightforward quantification through 1D peak integrals, we demonstrate here the direct use of 13C–13C CT-TOCSY spectra for metabolite quantification. This is accomplished through the quantum-mechanical treatment of the TOCSY magnetization transfer at short and long mixing times or by the use of analytical approximations, which are solely based on the knowledge of the carbon-backbone topologies. The methods are demonstrated for carbohydrate and amino-acid mixtures. PMID:23773204

  12. Quantitative H and K band spectroscopy of Galactic OB-stars at medium resolution

    E-print Network

    T. Repolust; J. Puls; M. M. Hanson; R. -P. Kudritzki; M. R. Mokiem

    2005-06-07

    In this paper we have analyzed 25 Galactic O and early B-stars by means of H and K band spectroscopy, with the primary goal to investigate to what extent a lone near-IR spectroscopy is able to recover stellar and wind parameters derived in the optical. Most of the spectra have been taken with SUBARU IRCS, at a resolution of 12,000, and with a very high S/N (200 or better). In order to synthesize the strategic H/He lines, we have used our recent, line-blanketed version of FASTWIND. First we investigated the predicted behaviour of the strategic lines. In contradiction to what one expects from the optical in the O-star regime, almost all photospheric H/HeI/HeII H/K band lines become stronger if the gravity decreases. Concerning H and HeII, this finding is related to the behaviour of Stark broadening as a function of electron density, which in the line cores is different for members of lower (optical) and higher (IR) series. Regarding HeI, the predicted behaviour is due to some subtle NLTE effects resulting in a stronger overpopulation of the lower level when the gravity decreases. For most of our objects, we obtained good fits, except for the line cores of Br_gamma in early O-stars with significant mass-loss, where this discrepancy might be an indirect effect of clumping. After having derived the stellar and wind parameters from the IR, we have compared them to results from previous optical analyses. Overall, the IR results coincide in most cases with the optical ones within the typical errors usually quoted for the corresponding parameters, i.e, an uncertainty in Teff of 5%, in log g of 0.1 dex and in Mdot of 0.2 dex, with lower errors at higher wind densities. Outliers above the 1-sigma level where found in four cases with respect to log g and in two cases for Mdot.

  13. Quantitative analysis of mixed hydrofluoric and nitric acids using Raman spectroscopy with partial least squares regression.

    PubMed

    Kang, Gumin; Lee, Kwangchil; Park, Haesung; Lee, Jinho; Jung, Youngjean; Kim, Kyoungsik; Son, Boongho; Park, Hyoungkuk

    2010-06-15

    Mixed hydrofluoric and nitric acids are widely used as a good etchant for the pickling process of stainless steels. The cost reduction and the procedure optimization in the manufacturing process can be facilitated by optically detecting the concentration of the mixed acids. In this work, we developed a novel method which allows us to obtain the concentrations of hydrofluoric acid (HF) and nitric acid (HNO(3)) mixture samples with high accuracy. The experiments were carried out for the mixed acids which consist of the HF (0.5-3wt%) and the HNO(3) (2-12wt%) at room temperature. Fourier Transform Raman spectroscopy has been utilized to measure the concentration of the mixed acids HF and HNO(3), because the mixture sample has several strong Raman bands caused by the vibrational mode of each acid in this spectrum. The calibration of spectral data has been performed using the partial least squares regression method which is ideal for local range data treatment. Several figures of merit (FOM) were calculated using the concept of net analyte signal (NAS) to evaluate performance of our methodology. PMID:20441916

  14. Quantitative measurement of intracellular transport of nanocarriers by spatio-temporal image correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Coppola, S.; Pozzi, D.; Candeloro De Sanctis, S.; Digman, M. A.; Gratton, E.; Caracciolo, G.

    2013-03-01

    Spatio-temporal image correlation spectroscopy (STICS) is a powerful technique for assessing the nature of particle motion in complex systems although it has been rarely used to investigate the intracellular dynamics of nanocarriers so far. Here we introduce a method for characterizing the mode of motion of nanocarriers and for quantifying their transport parameters on different length scales from single-cell to subcellular level. Using this strategy we were able to study the mechanisms responsible for the intracellular transport of DOTAP-DOPC/DNA (DOTAP: 1,2-dioleoyl-3-trimethylammonium-propane; DOPC: dioleoylphosphocholine) and DC-Chol-DOPE/DNA (DC-Chol: 3?-[N-(N,N-dimethylaminoethane)-carbamoyl] cholesterol; DOPE: dioleoylphosphatidylethanolamine) lipoplexes in CHO-K1 (CHO: Chinese hamster ovary) live cells. Measurement of both diffusion coefficients and velocity vectors (magnitude and direction) averaged over regions of the cell revealed the presence of distinct modes of motion. Lipoplexes diffused slowly on the cell surface (diffusion coefficient: D ? 0.003 ?m2 s-1). In the cytosol, the lipoplexes’ motion was characterized by active transport with average velocity v ? 0.03 ?m2 s-1 and random motion. The method permitted us to generate an intracellular transport map showing several regions of concerted motion of lipoplexes.

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

    PubMed Central

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

    2012-01-01

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

  16. Quantitative analysis of WC stars Constraints on neon abundances from ISO/SWS spectroscopy

    E-print Network

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

    2000-01-01

    Neon abundances are derived in four Galactic WC stars -- gamma Vel (WR11, WC8+O7.5III), HD156385 (WR90, WC7), HD192103 (WR135, WC8), and WR146 (WC5+O8) - using mid-infrared fine structure lines obtained with ISO/SWS. Stellar parameters for each star are derived using a non-LTE model atmospheric code (Hillier & Miller 1998) together with ultraviolet (IUE), optical (INT, AAT) and infrared (UKIRT, ISO) spectroscopy. In the case of gamma Vel, we adopt results from De Marco et al. (2000), who followed an identical approach. ISO/SWS datasets reveal the [NeIII] 15.5um line in each of our targets, while [NeII] 12.8um, [SIV] 10.5um and [SIII] 18.7um are observed solely in gamma Vel. Using a method updated from Barlow et al. (1988) to account for clumped winds, we derive Ne/He=3-4x10^-3 by number, plus S/He=6x10^-5 for gamma Vel. Neon is highly enriched, such that Ne/S in gamma Vel is eight times higher than cosmic values. However, observed Ne/He ratios are a factor of two times lower than predictions of current ev...

  17. Vibrational spectroscopy and microspectroscopy analyzing qualitatively and quantitatively pharmaceutical hot melt extrudates.

    PubMed

    Netchacovitch, L; Thiry, J; De Bleye, C; Chavez, P-F; Krier, F; Sacré, P-Y; Evrard, B; Hubert, Ph; Ziemons, E

    2015-09-10

    Since the last decade, more and more Active Pharmaceutical Ingredient (API) candidates have poor water solubility inducing low bioavailability. These molecules belong to the Biopharmaceutical Classification System (BCS) classes II and IV. Thanks to Hot-Melt Extrusion (HME), it is possible to incorporate these candidates in pharmaceutical solid forms. Indeed, HME increases the solubility and the bioavailability of these drugs by encompassing them in a polymeric carrier and by forming solid dispersions. Moreover, in 2004, the FDA's guidance initiative promoted the usefulness of Process Analytical Technology (PAT) tools when developing a manufacturing process. Indeed, the main objective when developing a new pharmaceutical process is the product quality throughout the production chain. The trend is to follow this parameter in real-time in order to react immediately when there is a bias. Vibrational spectroscopic techniques, NIR and Raman, are useful to analyze processes in-line. Moreover, off-line Raman microspectroscopy is more and more used when developing new pharmaceutical processes or when analyzing optimized ones by combining the advantages of Raman spectroscopy and imaging. It is an interesting tool for homogeneity and spatial distribution studies. This review treats about spectroscopic techniques analyzing a HME process, as well off-line as in-line, presenting their advantages and their complementarities. PMID:25704954

  18. Quantitative analysis of single-molecule force spectroscopy on folded chromatin fibers

    PubMed Central

    Meng, He; Andresen, Kurt; van Noort, John

    2015-01-01

    Single-molecule techniques allow for picoNewton manipulation and nanometer accuracy measurements of single chromatin fibers. However, the complexity of the data, the heterogeneity of the composition of individual fibers and the relatively large fluctuations in extension of the fibers complicate a structural interpretation of such force-extension curves. Here we introduce a statistical mechanics model that quantitatively describes the extension of individual fibers in response to force on a per nucleosome basis. Four nucleosome conformations can be distinguished when pulling a chromatin fiber apart. A novel, transient conformation is introduced that coexists with single wrapped nucleosomes between 3 and 7 pN. Comparison of force-extension curves between single nucleosomes and chromatin fibers shows that embedding nucleosomes in a fiber stabilizes the nucleosome by 10 kBT. Chromatin fibers with 20- and 50-bp linker DNA follow a different unfolding pathway. These results have implications for accessibility of DNA in fully folded and partially unwrapped chromatin fibers and are vital for understanding force unfolding experiments on nucleosome arrays. PMID:25779043

  19. Vibrational spectroscopy and chemometrics for rapid, quantitative analysis of bitter acids in hops (Humulus lupulus).

    PubMed

    Killeen, Daniel P; Andersen, David H; Beatson, Ron A; Gordon, Keith C; Perry, Nigel B

    2014-12-31

    Hops, Humulus lupulus, are grown worldwide for use in the brewing industry to impart characteristic flavor and aroma to finished beer. Breeders produce many varietal crosses with the aim of improving and diversifying commercial hops varieties. The large number of crosses critical to a successful breeding program imposes high demands on the supporting chemical analytical laboratories. With the aim of reducing the analysis time associated with hops breeding, quantitative partial least-squares regression (PLS-R) models have been produced, relating reference data acquired by the industrial standard HPLC and UV methods, to vibrational spectra of the same, chemically diverse hops sample set. These models, produced from rapidly acquired infrared (IR), near-infrared (NIR), and Raman spectra, were appraised using standard statistical metrics. Results demonstrated that all three spectroscopic methods could be used for screening hops for ?-acid, total bitter acids, and cohumulone concentrations in powdered hops. Models generated from Raman and IR spectra also showed potential for use in screening hops varieties for xanthohumol concentrations. NIR analysis was performed using both a standard benchtop spectrometer and a portable NIR spectrometer, with comparable results obtained by both instruments. Finally, some important vibrational features of cohumulone, colupulone, and xanthohumol were assigned using DFT calculations, which allow more insightful interpretation of PLS-R latent variable plots. PMID:25485767

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

    NASA Astrophysics Data System (ADS)

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

    2006-02-01

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

  1. Near Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Jha, Shyam N.

    The discovery of near-infrared energy is ascribed to Herschel in the nineteenth century; the first industrial application however began in the 1950s. Initially near infrared spectroscopy (NIRS) was used only as an add-on unit to other optical devices, that used other wavelengths such as ultraviolet (UV), visible (Vis), or mid-infrared (MIR) spectrometers. In the 1980s, a single unit, stand-alone NIRS system was made available, but the application of NIRS was focused more on chemical analysis. With the introduction of light-fibre optics in the mid 1980s and the monochromator-detector developments in early 1990s, NIRS became a more powerful tool for scientific research. This optical method can be used in a number of fields of science including physics, physiology, medicine and food.

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

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

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

  3. Electrically Injected UV-Visible Nanowire Lasers

    SciTech Connect

    Wang, George T.; Li, Changyi; Li, Qiming; Liu, Sheng; Wright, Jeremy Benjamin; Brener, Igal; Luk, Ting -Shan; Chow, Weng W.; Leung, Benjamin; Figiel, Jeffrey J.; Koleske, Daniel D.; Lu, Tzu-Ming

    2015-09-01

    There is strong interest in minimizing the volume of lasers to enable ultracompact, low-power, coherent light sources. Nanowires represent an ideal candidate for such nanolasers as stand-alone optical cavities and gain media, and optically pumped nanowire lasing has been demonstrated in several semiconductor systems. Electrically injected nanowire lasers are needed to realize actual working devices but have been elusive due to limitations of current methods to address the requirement for nanowire device heterostructures with high material quality, controlled doping and geometry, low optical loss, and efficient carrier injection. In this project we proposed to demonstrate electrically injected single nanowire lasers emitting in the important UV to visible wavelengths. Our approach to simultaneously address these challenges is based on high quality III-nitride nanowire device heterostructures with precisely controlled geometries and strong gain and mode confinement to minimize lasing thresholds, enabled by a unique top-down nanowire fabrication technique.

  4. Quantitative spectroscopy of blue supergiants in metal-poor dwarf galaxy NGC 3109

    SciTech Connect

    Hosek, Matthew W. Jr.; Kudritzki, Rolf-Peter; Bresolin, Fabio; Urbaneja, Miguel A.; Przybilla, Norbert; Evans, Christopher J.; Pietrzy?ski, Grzegorz; Gieren, Wolfgang; Carraro, Giovanni E-mail: kud@ifa.hawaii.edu E-mail: Miguel.Urbaneja-Perez@uibk.ac.at E-mail: chris.evans@stfc.ac.uk E-mail: wgieren@astro-udec.cl

    2014-04-20

    We present a quantitative analysis of the low-resolution (?4.5 Å) spectra of 12 late-B and early-A blue supergiants (BSGs) in the metal-poor dwarf galaxy NGC 3109. A modified method of analysis is presented which does not require use of the Balmer jump as an independent T {sub eff} indicator, as used in previous studies. We determine stellar effective temperatures, gravities, metallicities, reddening, and luminosities, and combine our sample with the early-B-type BSGs analyzed by Evans et al. to derive the distance to NGC 3109 using the flux-weighted gravity-luminosity relation (FGLR). Using primarily Fe-group elements, we find an average metallicity of [ Z-bar ] = –0.67 ± 0.13, and no evidence of a metallicity gradient in the galaxy. Our metallicities are higher than those found by Evans et al. based on the oxygen abundances of early-B supergiants ([ Z-bar ] = –0.93 ± 0.07), suggesting a low ?/Fe ratio for the galaxy. We adjust the position of NGC 3109 on the BSG-determined galaxy mass-metallicity relation accordingly and compare it to metallicity studies of H II regions in star-forming galaxies. We derive an FGLR distance modulus of 25.55 ± 0.09 (1.27 Mpc) that compares well with Cepheid and tip of the red giant branch distances. The FGLR itself is consistent with those found in other galaxies, demonstrating the reliability of this method as a measure of extragalactic distances.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  6. [Research on the Quantitative Analysis for In-Situ Detection of Acid Radical Ions Using Laser Raman Spectroscopy].

    PubMed

    Chen, Jing; Li, Ying; Du, Zeng-feng; Gu, Yan-hong; Guo, Jin-jia

    2015-09-01

    Laser Raman spectroscopy as an in situ analytical technology can enable detailed investigation of the ocean environment. It is necessary to set up a quantitative analysis method based on laser Raman spectroscopy to understand the marine status in situ. In the laboratory investigations, varied concentration of HCO3(-), SO4(2-) and coastal waters of Qingdao are taken as the samples, operating 532 nm of laser, using fiber optic probes to simulate detection mode in situ. Raman spectra are analyzed using the method of internal standard normalization, multiple linear regression (MLR), general Partial Least Squares (PLS) and PLS based on dominant factor respectively in data processing. It was found that correlation coefficients of calibration curves are not high in internal standard normalization method and predicted relative errors on the prepared samples are much high, so internal standard normalization method cannot be effectively used in the quantitative analysis of HCO3(-), SO4(2-) in the water. And with the multiple linear regression, the analysis accuracy was improved effectively. The calibration curve of PLS based on dominant factor showed that the SO4(2-) and HCO3(-) of pre-made solution with correlation coefficient R2 of 0.990 and 0.916 respectively. The 30 mmol · L(-1) of SO4(2-) and 20 mmol · L(-1) of HCO3(-) in two target samples were determined with the relative errors lower than 3.262% and 5.267% respectively. SO4(2-) in the coastal waters as the research object was analyzed by above-mentioned methods, comparing with 28.01 mmol · L(-1) by ion chromatography. It was demonstrated that PLS based on dominant factor method is superior to the rest of the three analysis methods, which can be used in situ calibration, with the mean relative error about 1.128%. All the results show that analysis accuracy would be improved by the PLS based on dominant factor method to predict concentration of acid radical ions. PMID:26669165

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  8. Quantitative analysis of chromium in potatoes by laser-induced breakdown spectroscopy coupled with linear multivariate calibration.

    PubMed

    Chen, Tianbing; Huang, Lin; Yao, Mingyin; Hu, Huiqin; Wang, Caihong; Liu, Muhua

    2015-09-01

    Laser-induced breakdown spectroscopy (LIBS) coupled with the linear multivariate regression method was utilized to analyze chromium (Cr) quantitatively in potatoes. The plasma was generated using a Nd:YAG laser, and the spectra were acquired by an Andor spectrometer integrated with an ICCD detector. The models between intensity of LIBS characteristic line(s) and concentration of Cr were constructed to predict quantitatively the content of target. The unary, binary, ternary, and quaternary variables were chosen for verifying the accuracy of linear regression calibration curves. The intensity of characteristic lines Cr (CrI: 425.43, 427.48, 428.97 nm) and Ca (CaI: 422.67, 428.30, 430.25, 430.77, 431.86 nm) were used as input data for the multivariate calculations. According to the results of linear regression, the model of quaternary linear regression was established better in comparing with the other three models. A good agreement was observed between the actual content provided by atomic absorption spectrometry and the predicted value obtained by the quaternary linear regression model. And the relative error was below 5.5% for validation samples S1 and S2. The result showed that the multivariate approach can obtain better predicted accuracy than the univariate ones. The result also suggested that the LIBS technique coupled with the linear multivariate calibration method could be a great tool to predict heavy metals in farm products in a rapid manner even though samples have similar elemental compositions. PMID:26368908

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

    PubMed

    Saravanan, S; Balachandran, V

    2014-09-15

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

  10. Disulfide-Linked Dinitroxides for Monitoring Cellular Thiol Redox Status through Electron Paramagnetic Resonance Spectroscopy.

    PubMed

    Legenzov, Eric A; Sims, Stephen J; Dirda, Nathaniel D A; Rosen, Gerald M; Kao, Joseph P Y

    2015-12-01

    Intracellular thiol-disulfide redox balance is crucial to cell health, and may be a key determinant of a cancer's response to chemotherapy and radiation therapy. The ability to assess intracellular thiol-disulfide balance may thus be useful not only in predicting responsiveness of cancers to therapy, but in assessing predisposition to disease. Assays of thiols in biology have relied on colorimetry or fluorimetry, both of which require UV-visible photons, which do not penetrate the body. Low-frequency electron paramagnetic resonance imaging (EPRI) is an emerging magnetic imaging technique that uses radio waves, which penetrate the body well. Therefore, in combination with tailored imaging agents, EPRI affords the opportunity to image physiology within the body. In this study, we have prepared water-soluble and membrane-permeant disulfide-linked dinitroxides, at natural isotopic abundance, and with D,(15)N-substitution. Thiols such as glutathione cleave the disulfides, with simple bimolecular kinetics, to yield the monomeric nitroxide species, with distinctive changes in the EPR spectrum. Using the D,(15)N-substituted disulfide-dinitroxide and EPR spectroscopy, we have obtained quantitative estimates of accessible intracellular thiol in cultured human lymphocytes. Our estimates are in good agreement with published measurements. This suggests that in vivo EPRI of thiol-disulfide balance is feasible. Finally, we discuss the constraints on the design of probe molecules that would be useful for in vivo EPRI of thiol redox status. PMID:26523485

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

    USGS Publications Warehouse

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

    2010-01-01

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

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

    PubMed

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

    2011-06-01

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

  13. [Application of interval selection methods in quantitative analysis of multicomponent mixtures by terahertz time-domain spectroscopy].

    PubMed

    Chen, Tao; Li, Zhi; Mo, Wei; Hu, Fang-rong

    2014-12-01

    Interval selection methods combined with terahertz time-domain spectroscopy (THz-TDS) technique were used to perform quantitative analysis of component concentrations in multicomponent mixtures. The THz spectra of 100 quaternary pharmaceutical mixtures composed of lactose monohydrate, acetaminophen, microcrystalline cellulose and soluble starch were measured using THz-TDS system. Four spectral interval selection methods, including iPLS, mwPLS, siPLS and biPLS, were employed to select spectral intervals of THz absorbance spectra of multicomponent mixtures and correlate THz absorbance spectra with the concentrations of lactose monohydrate. The mwPLS method yielded the most accurate result as compared with the other three interval selection methods and full-spectrum PLS. The optimal mwPLS model was obtained with lower root mean square error of cross-validation (RMSECV) of 0.9803, lower root mean square error of prediction (RMSEP) of 1.1141, higher correlation coefficient for calibration (Rc) of 0.9960, and higher correlation coefficient for prediction (Rp) of 0.9951. Experimental results demonstrate that spectral interval selection combined with THz-TDS could be successfully applied as an accurate and rapid method to determine component concentrations in multicomponent mixtures. PMID:25881416

  14. Optical micro-spectroscopy of single metallic nanoparticles: quantitative extinction and transient resonant four-wave mixing.

    PubMed

    Payne, Lukas; Zoriniants, George; Masia, Francesco; Arkill, Kenton P; Verkade, Paul; Rowles, Darren; Langbein, Wolfgang; Borri, Paola

    2015-12-12

    We report a wide-field imaging method to rapidly and quantitatively measure the optical extinction cross-section ?ext (also polarisation resolved) of a large number of individual gold nanoparticles, for statistically-relevant single particle analysis. We demonstrate a sensitivity of 5 nm(2) in ?ext, enabling detection of single 5 nm gold nanoparticles with total acquisition times in the 1 min range. Moreover, we have developed an analytical model of the polarisation resolved ?ext, which enabled us to extract geometrical particle aspect ratios from the measured ?ext. Using this method, we have characterized a large number of nominally-spherical gold nanoparticles in the 10-100 nm size range. Furthermore, the method provided measurements of in-house fabricated nanoparticle conjugates, allowing distinction of individual dimers from single particles and larger aggregates. The same particle conjugates were investigated correlatively by phase-resolved transient resonant four-wave mixing micro-spectroscopy. A direct comparison of the phase-resolved response between single gold nanoparticles and dimers highlighted the promise of the four-wave mixing technique for sensing applications with dimers as plasmon rulers. PMID:26416674

  15. Quantitative measurement of cerebral blood flow in a juvenile porcine model by depth-resolved near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Elliott, Jonathan T.; Diop, Mamadou; Tichauer, Kenneth M.; Lee, Ting-Yim; Lawrence, Keith St.

    2010-05-01

    Nearly half a million children and young adults are affected by traumatic brain injury each year in the United States. Although adequate cerebral blood flow (CBF) is essential to recovery, complications that disrupt blood flow to the brain and exacerbate neurological injury often go undetected because no adequate bedside measure of CBF exists. In this study we validate a depth-resolved, near-infrared spectroscopy (NIRS) technique that provides quantitative CBF measurement despite significant signal contamination from skull and scalp tissue. The respiration rates of eight anesthetized pigs (weight: 16.2+/-0.5 kg, age: 1 to 2 months old) are modulated to achieve a range of CBF levels. Concomitant CBF measurements are performed with NIRS and CT perfusion. A significant correlation between CBF measurements from the two techniques is demonstrated (r2=0.714, slope=0.92, p<0.001), and the bias between the two techniques is -2.83 mL.min-1.100 g-1 (CI0.95: -19.63 mL.min-1.100 g-1-13.9 mL.min-1.100 g-1). This study demonstrates that accurate measurements of CBF can be achieved with depth-resolved NIRS despite significant signal contamination from scalp and skull. The ability to measure CBF at the bedside provides a means of detecting, and thereby preventing, secondary ischemia during neurointensive care.

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

    PubMed

    2014-10-01

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

  17. Towards a non-invasive quantitative analysis of the organic components in museum objects varnishes by vibrational spectroscopies: methodological approach.

    PubMed

    Daher, Céline; Pimenta, Vanessa; Bellot-Gurlet, Ludovic

    2014-11-01

    The compositions of ancient varnishes are mainly determined destructively by separation methods coupled to mass spectrometry. In this study, a methodology for non-invasive quantitative analyses of varnishes by vibrational spectroscopies is proposed. For that, experimental simplified varnishes of colophony and linseed oil were prepared according to 18th century traditional recipes with an increasing mass concentration ratio of colophony/linseed oil. FT-Raman and IR analyses using ATR and non-invasive reflectance modes were done on the "pure" materials and on the different mixtures. Then, a new approach involving spectral decomposition calculation was developed considering the mixture spectra as a linear combination of the pure materials ones, and giving a relative amount of each component. Specific spectral regions were treated and the obtained results show a good accuracy between the prepared and calculated amounts of the two compounds. We were thus able to detect and quantify from 10% to 50% of colophony in linseed oil using non-invasive techniques that can also be conducted in situ with portable instruments when it comes to museum varnished objects and artifacts. PMID:25127604

  18. Quantitative Applications of Deep-Sea Raman Spectroscopy: Geochemistry of 1,4- thioxane in sea water

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Hester, K. C.; Walz, P. M.; Peltzer, E. T.; Brewer, P. G.

    2008-12-01

    We have developed quantitative Raman spectroscopic techniques for the novel detection of dissolved species in sea water to determine their fundamental properties. In this example we use a field-deployable Raman system to determine the solubility of 1,4-thioxane (TO) in sea water as 0.65 to 0.63 mol/kg H2O between 4.5°C and 25.0°C (which varies greatly from an earlier report of 2.75 mol/kg H2O), and to assess the conditions under which it may form a hydrate. TO is of unusual environmental interest as a breakdown product of the chemical weapon mustard gas, and thus development of non-contact field- deployable sensing techniques is highly desirable. Raman spectroscopy has typically been considered as only a qualitative technique due to the complexity of the optical path and the substantial changes in components between different instruments. We show here that by self-referencing to the ubiquitous water peaks (the water ?2 mode from 1500 to 1800 cm-1) we can derive quantitative information with a precision of ± 4%, and provide essential new information. The long-term fate of large quantities of chemical weapons disposed of in the ocean some 50 years ago is poorly known. Part of this lacking knowledge can be attributed to the hazards associated with the direct study of these materials leaving ocean scientists vulnerable when sampling in inadequately marked sites. Mustard gas (1,1'-thiobis[2-chloroethane]) represents the largest tonnage of material disposed of until the 1972 London Convention banned such activities. Thus there is strong interest in determining the fate and lifetime of these materials, their decomposition products, and the extent of the affected zones. We have earlier shown that TO forms a hydrate with a help-gas, such as methane or hydrogen sulfide, and that the temperature, pressure and reducing conditions required for hydrate formation commonly occur at known disposal sites. In fact, a mixed TO hydrate is more stable than methane hydrate by almost 10°C. Here we show that in the presence of hydrate formation, as with other hydrate guest molecules, the TO solubility trend was reversed and solubility decreased in response to lower temperatures. The relatively low solubility in water coupled with the ability to form a hydrate within marine sediments can greatly decrease molecular mobility and increase chemical lifetime. Mixing will reduce concentrations of TO in the ocean water column below the detection limits established here. But the solubility data reveals the concentrations that will characterize marine pore waters at such sites, and these are readily detectable. Development of pore water Raman sensing techniques are underway.

  19. Quantitative determination of competitive molecular adsorption on gold nanoparticles using attenuated total reflectance-Fourier transform infrared spectroscopy.

    PubMed

    Tsai, De-Hao; Davila-Morris, Melissa; DelRio, Frank W; Guha, Suvajyoti; Zachariah, Michael R; Hackley, Vincent A

    2011-08-01

    Surface-sensitive quantitative studies of competitive molecular adsorption on nanoparticles were conducted using a modified attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy method. Adsorption isotherms for thiolated poly(ethylene glycol) (SH-PEG) on gold nanoparticles (AuNPs) as a function of molecular mass (1, 5, and 20 kDa) were characterized. We find that surface density of SH-PEG on AuNPs is inversely proportional to the molecular mass (M(m)). Equilibrium binding constants for SH-PEG, obtained using the Langmuir adsorption model, show the binding affinity for SH-PEG is proportional to M(m). Simultaneous competitive adsorption between mercaptopropionic acid (MPA) and 5 kDa SH-PEG (SH-PEG5K) was investigated, and we find that MPA concentration is the dominant factor influencing the surface density of both SH-PEG5K and MPA, whereas the concentration of SH-PEG5K affects only SH-PEG5K surface density. Electrospray differential mobility analysis (ES-DMA) was employed as an orthogonal characterization technique. ES-DMA results are consistent with the results obtained by ATR-FTIR, confirming our conclusions about the adsorption process in this system. Ligand displacement competitive adsorption, where the displacing molecular species is added after completion of the ligand surface binding, was also interrogated by ATR-FTIR. Results indicate that for SH-PEG increasing M(m) yields greater stability on AuNPs when measured against displacement by bovine serum albumin (BSA) as a model serum protein. In addition, the binding affinity of BSA to AuNPs is inhibited for SH-PEG conjugated AuNPs, an effect that is enhanced at higher SH-PEG M(m) values. PMID:21726083

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

    NASA Astrophysics Data System (ADS)

    Heard, Dwayne

    2015-04-01

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

  1. Spectroscopy characterization of anthracene in SDS/BA/H 2O system

    NASA Astrophysics Data System (ADS)

    Xu, Hui; Liu, Quanwen

    2008-07-01

    Spectroscopy characterization of anthracene in sodium dodecyl sulfate (SDS)/benzyl alcohol (BA)/water (H 2O) microemulsion was studied by UV-visible absorption and fluorescence emission spectroscopy. The impact of the composition and structure of the microemulsion on spectroscopy characterization of anthracene were discussed. At the same time, we indicated the location of anthracene in microemulsion. The results indicated that in O/W microemulsion in SDS/BA/H 2O system, anthracene exists both in the membrane phase and oil core, while in W/O microemulsion, anthracene exists in the oil continuous phase.

  2. Spectroscopy characterization of anthracene in SDS/BA/H2O system.

    PubMed

    Xu, Hui; Liu, Quanwen

    2008-07-01

    Spectroscopy characterization of anthracene in sodium dodecyl sulfate (SDS)/benzyl alcohol (BA)/water (H(2)O) microemulsion was studied by UV-visible absorption and fluorescence emission spectroscopy. The impact of the composition and structure of the microemulsion on spectroscopy characterization of anthracene were discussed. At the same time, we indicated the location of anthracene in microemulsion. The results indicated that in O/W microemulsion in SDS/BA/H(2)O system, anthracene exists both in the membrane phase and oil core, while in W/O microemulsion, anthracene exists in the oil continuous phase. PMID:17804283

  3. Top-hat cw-laser-induced time-resolved mode-mismatched thermal lens spectroscopy for quantitative analysis of low-absorption materials.

    PubMed

    Astrath, Nelson G C; Astrath, Francine B G; Shen, Jun; Zhou, Jianqin; Pedreira, Paulo R B; Malacarne, Luis C; Bento, Antonio C; Baesso, Mauro L

    2008-07-01

    Thermal lens spectroscopy is a highly sensitive and versatile photothermal technique for material analysis, providing optical and thermal properties. To use less expensive multimode non-Gaussian lasers for quantitative analysis of low-absorption materials, this Letter presents a theoretical model for time-resolved mode-mismatched thermal lens spectroscopy induced by a cw laser with a top-hat profile. The temperature profile in a sample was calculated, and the intensity of the probe beam center at the detector plane was also derived using the Fresnel diffraction theory. Experimental validation was performed with glass samples, and the results were found well consistent with literature values of the thermo-optical properties of the samples. PMID:18594666

  4. Application of the quantitative detection of a change in concentration of magnesium stearate in a feeder tube of tableting manufacture by real-time near-infrared spectroscopy.

    PubMed

    Sasakura, D; Nakayama, K; Chikuma, T

    2015-10-01

    Process analytical technology is important for the analysis and control of manufacturing processes. Near-infrared spectroscopy is widely used in various process analytical technologies for the analysis of the chemical componentsof solid dosage forms. Lubrication is an important process carried out before a tablet is produced. In this process, the concentration of lubricant, such as magnesium stearate (StMg), might change for one of many reasons during powder transport, which would be a critical problem such as variation in tablet compressibility and dissolution failure of compressed tablets. Our group investigated the feasibility of the quantitative monitoring of a change in the concentration of StMg in the feeder tube of tableting equipment employing real-time near-infrared spectroscopy. PMID:26601418

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

    EPA Science Inventory

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

  6. A Rapid and High-Throughput Quantitation Assay of the Nuclear Factor ?B Activity Using Fluorescence Correlation Spectroscopy in the Setting of Clinical Laboratories

    PubMed Central

    Harada, Kenu; Mikuni, Shintaro; Beppu, Hideyuki; Niimi, Hideki; Abe, Shigeki; Hano, Nobuko; Yamagata, Koichi; Kinjo, Masataka; Kitajima, Isao

    2013-01-01

    Background Transcription factor nuclear factor-?B (NF-?B) plays a key role in the regulation of immune responses to inflammation. However, convenient assay systems to quantitate the NF-?B activity level in a timely manner are not available in the setting of clinical laboratories. Therefore, we developed a novel and high-throughput quantitative assay based on fluorescence correlation spectroscopy (FCS) to detect the NF-?B activity level in cellular nuclear extracts and evaluated the performance of this method. The basic principle of this assay is to calculate the binding fraction of NF-?B to fluorescent-labeled DNA probes, which contain NF-?B binding sites. Methods Non-fluorescent competitive probes are employed to normalize the influence of the viscosity of the nuclear extracts between samples and to eliminate the influence of nonspecific binding of the fluorescent probes. To confirm accurate quantitation, human recombinant NF-?B p50 was mixed into U937 cell nuclear extracts, and the binding fraction of the fluorescent probes to NF-?B in the mixture was calculated for quantitation. To evaluate whether this method can be applied to measure the NF-?B activity in human lymphocytes, the NF-?B activity levels of systemic inflammatory response syndrome patients during perioperative periods were measured. Results The percentage recovery was 88.9%. The coefficients of variation of the intra-assay were approximately 10%. NF-?B activity levels during the perioperative period can were successfully measured. The assay time for the FCS measurement was within 20 minutes. Conclusions This assay system can be used to quantitate NF-?B activity levels in a timely manner in the setting of hospital laboratories. PMID:24124497

  7. Homogeneity testing and quantitative analysis of manganese (Mn) in vitrified Mn-doped glasses by laser-induced breakdown spectroscopy (LIBS)

    SciTech Connect

    Unnikrishnan, V. K.; Nayak, Rajesh; Kartha, V. B.; Santhosh, C. E-mail: unnikrishnan.vk@manipal.edu; Sonavane, M. S.; Yeotikar, R. G.; Shah, M. L.; Gupta, G. P.; Suri, B. M.

    2014-09-15

    Laser-induced breakdown spectroscopy (LIBS), an atomic emission spectroscopy method, has rapidly grown as one of the best elemental analysis techniques over the past two decades. Homogeneity testing and quantitative analysis of manganese (Mn) in manganese-doped glasses have been carried out using an optimized LIBS system employing a nanosecond ultraviolet Nd:YAG laser as the source of excitation. The glass samples have been prepared using conventional vitrification methods. The laser pulse irradiance on the surface of the glass samples placed in air at atmospheric pressure was about 1.7×10{sup 9} W/cm{sup 2}. The spatially integrated plasma emission was collected and imaged on to the spectrograph slit using an optical-fiber-based collection system. Homogeneity was checked by recording LIBS spectra from different sites on the sample surface and analyzing the elemental emission intensities for concentration determination. Validation of the observed LIBS results was done by comparison with scanning electron microscope- energy dispersive X-ray spectroscopy (SEM-EDX) surface elemental mapping. The analytical performance of the LIBS system has been evaluated through the correlation of the LIBS determined concentrations of Mn with its certified values. The results are found to be in very good agreement with the certified concentrations.

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

    SciTech Connect

    Reich, F.R.

    1997-08-11

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

  9. Near infrared spectroscopy in combination with chemometrics as a process analytical technology (PAT) tool for on-line quantitative monitoring of alcohol precipitation.

    PubMed

    Jin, Ye; Wu, Zengzeng; Liu, Xuesong; Wu, Yongjiang

    2013-04-15

    The application of near infrared (NIR) spectroscopy for on-line quantitative monitoring of alcohol precipitation of the Danhong injection was investigated. For the NIR measurements, two fiber optic probes designed to transmit NIR radiation through a 2mm path length flow cell were applied to collect spectra in real-time. Particle swarm optimization- (PSO-) based least square support vector machines (LS-SVM) and partial least squares (PLS) models were developed for quantitative analysis of the critical intermediate quality attributes: the soluble solid content (SSC) and concentrations of danshensu (DSS), protocatechuic aldehyde (PA), hydroxysafflor yellow A (HSYA) and salvianolic acid B (SAB). The optimal models were then used for on-line quantitative monitoring of alcohol precipitation. The results showed that the PSO-based LS-SVM with a radial basis function (RBF) kernel was slightly better than the conventional PLS method, even though both methods exhibited satisfactory fitting results and predictive abilities. In this study, successful models were built and applied on-line; these models proffer real-time data and instant feedback about alcohol precipitation. PMID:23357639

  10. Salicylate Detection by Complexation with Iron(III) and Optical Absorbance Spectroscopy: An Undergraduate Quantitative Analysis Experiment

    ERIC Educational Resources Information Center

    Mitchell-Koch, Jeremy T.; Reid, Kendra R.; Meyerhoff, Mark E.

    2008-01-01

    An experiment for the undergraduate quantitative analysis laboratory involving applications of visible spectrophotometry is described. Salicylate, a component found in several medications, as well as the active by-product of aspirin decomposition, is quantified. The addition of excess iron(III) to a solution of salicylate generates a deeply…

  11. Passive Fourier-transform infrared spectroscopy of chemical plumes: an algorithm for quantitative interpretation and real-time background removal

    NASA Astrophysics Data System (ADS)

    Polak, Mark L.; Hall, Jeffrey L.; Herr, Kenneth C.

    1995-08-01

    We present a ratioing algorithm for quantitative analysis of the passive Fourier-transform infrared spectrum of a chemical plume. We show that the transmission of a near-field plume is given by tau plume = (Lobsd - Lbb-plume)/(Lbkgd - Lbb-plume), where tau plume is the frequency-dependent transmission of the plume, L obsd is the spectral radiance of the scene that contains the plume, Lbkgd is the spectral radiance of the same scene without the plume, and Lbb-plume is the spectral radiance of a blackbody at the plume temperature. The algorithm simultaneously achieves background removal, elimination of the spectrometer internal signature, and quantification of the plume spectral transmission. It has applications to both real-time processing for plume visualization and quantitative measurements of plume column densities. The plume temperature (Lbb-plume ), which is not always precisely known, can have a profound effect on the quantitative interpretation of the algorithm and is discussed in detail. Finally, we provide an illustrative example of the use of the algorithm on a trichloroethylene and acetone plume.

  12. Laser-induced Breakdown spectroscopy quantitative analysis method via adaptive analytical line selection and relevance vector machine regression model

    NASA Astrophysics Data System (ADS)

    Yang, Jianhong; Yi, Cancan; Xu, Jinwu; Ma, Xianghong

    2015-05-01

    A new LIBS quantitative analysis method based on analytical line adaptive selection and Relevance Vector Machine (RVM) regression model is proposed. First, a scheme of adaptively selecting analytical line is put forward in order to overcome the drawback of high dependency on a priori knowledge. The candidate analytical lines are automatically selected based on the built-in characteristics of spectral lines, such as spectral intensity, wavelength and width at half height. The analytical lines which will be used as input variables of regression model are determined adaptively according to the samples for both training and testing. Second, an LIBS quantitative analysis method based on RVM is presented. The intensities of analytical lines and the elemental concentrations of certified standard samples are used to train the RVM regression model. The predicted elemental concentration analysis results will be given with a form of confidence interval of probabilistic distribution, which is helpful for evaluating the uncertainness contained in the measured spectra. Chromium concentration analysis experiments of 23 certified standard high-alloy steel samples have been carried out. The multiple correlation coefficient of the prediction was up to 98.85%, and the average relative error of the prediction was 4.01%. The experiment results showed that the proposed LIBS quantitative analysis method achieved better prediction accuracy and better modeling robustness compared with the methods based on partial least squares regression, artificial neural network and standard support vector machine.

  13. Raman spectroscopy provides a rapid, non-invasive method for quantitation of starch in live, unicellular microalgae.

    PubMed

    Ji, Yuetong; He, Yuehui; Cui, Yanbin; Wang, Tingting; Wang, Yun; Li, Yuanguang; Huang, Wei E; Xu, Jian

    2014-12-01

    Conventional methods for quantitation of starch content in cells generally involve starch extraction steps and are usually labor intensive, thus a rapid and non-invasive method will be valuable. Using the starch-producing unicellular microalga Chlamydomonas reinhardtii as a model, we employed a customized Raman spectrometer to capture the Raman spectra of individual single cells under distinct culture conditions and along various growth stages. The results revealed a nearly linear correlation (R(2) = 0.9893) between the signal intensity at 478 cm(-1) and the starch content of the cells. We validated the specific correlation by showing that the starch-associated Raman peaks were eliminated in a mutant strain where the AGPase (ADP-glucose pyrophosphorylase) gene was disrupted and consequentially the biosynthesis of starch blocked. Furthermore, the method was validated in an industrial algal strain of Chlorella pyrenoidosa. This is the first demonstration of starch quantitation in individual live cells. Compared to existing cellular starch quantitation methods, this single-cell Raman spectra-based approach is rapid, label-free, non-invasive, culture-independent, low-cost, and potentially able to simultaneously track multiple metabolites in individual live cells, therefore should enable many new applications. PMID:24906189

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

    NASA Astrophysics Data System (ADS)

    Nawar, Said; Buddenbaum, Henning; Hill, Joachim

    2014-05-01

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

  15. Biogenic unmodified gold nanoparticles for selective and quantitative detection of cerium using UV-vis spectroscopy and photon correlation spectroscopy (DLS).

    PubMed

    Priyadarshini, E; Pradhan, N; Panda, P K; Mishra, B K

    2015-06-15

    The ability of self-functionalized biogenic GNPs towards highly selective colorimetric detection of rare earth element cerium is being reported for the first time. GNPs underwent rapid aggregation on addition of cerium indicated by red shift of SPR peak followed by complete precipitation. Hereby, this concept of co-ordination of cerium ions onto the GNP surface has been utilized for detection of cerium. The remarkable capacity of GNPs to sensitively detect Ce without proves beneficial compared to previous reports of colorimetric sensing. MDL was 15 and 35 ppm by DLS and UV-vis spectroscopy respectively, suggesting DLS to be highly sensitive and a practical alternative in ultrasensitive detection studies. The sensing system showed a good linear fit favouring feasible detection of cerium in range of 2-50 ppm. Similar studies further showed the superior selectivity of biogenic GNPs compared to chemically synthesized counterparts. The sensing system favours on-site analysis as it overcomes need of complex instrumentation, lengthy protocols and surface modification of GNP. PMID:25643600

  16. Combined fiber probe for fluorescence lifetime and Raman spectroscopy.

    PubMed

    Dochow, Sebastian; Ma, Dinglong; Latka, Ines; Bocklitz, Thomas; Hartl, Brad; Bec, Julien; Fatakdawala, Hussain; Marple, Eric; Urmey, Kirk; Wachsmann-Hogiu, Sebastian; Schmitt, Michael; Marcu, Laura; Popp, Jürgen

    2015-11-01

    In this contribution we present a dual modality fiber optic probe combining fluorescence lifetime imaging (FLIm) and Raman spectroscopy for in vivo endoscopic applications. The presented multi-spectroscopy probe enables efficient excitation and collection of fluorescence lifetime signals for FLIm in the UV/visible wavelength region, as well as of Raman spectra in the near-IR for simultaneous Raman/FLIm imaging. The probe was characterized in terms of its lateral resolution and distance dependency of the Raman and FLIm signals. In addition, the feasibility of the probe for in vivo FLIm and Raman spectral characterization of tissue was demonstrated. Graphical Abstract An image comparison between FLIm and Raman spectroscopy acquired with the bimodal probe onseveral tissue samples. PMID:26093843

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

    SciTech Connect

    Raeburn, S.P.; Ilton, E.S.; Veblen, D.R.

    1997-11-01

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

  18. Quantitative compositional profiling of conjugated quantum dots with single atomic layer depth resolution via time-of-flight medium-energy ion scattering spectroscopy.

    PubMed

    Jung, Kang-Won; Yu, Hyunung; Min, Won Ja; Yu, Kyu-Sang; Sortica, M A; Grande, Pedro L; Moon, DaeWon

    2014-01-21

    We report the quantitative compositional profiling of 3-5 nm CdSe/ZnS quantum dots (QDs) conjugated with a perfluorooctanethiol (PFOT) layer using the newly developed time-of-flight (TOF) medium-energy ion scattering (MEIS) spectroscopy with single atomic layer resolution. The collection efficiency of TOF-MEIS is 3 orders of magnitude higher than that of conventional MEIS, enabling the analysis of nanostructured materials with minimized ion beam damage and without ion neutralization problems. The spectra were analyzed using PowerMEIS ion scattering simulation software to allow a wide acceptance angle. Thus, the composition and core-shell structure of the CdSe cores and ZnS shells were determined with a 3% composition uncertainty and a 0.2-nm depth resolution. The number of conjugated PFOT molecules per QD was also quantified. The size and composition of the QDs were consistent with those obtained from high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy, respectively. We suggest TOF-MEIS as a nanoanalysis technique to successfully elucidate the core-shell and conjugated layer structures of QDs, which is critical for the practical application of QDs in various nano- and biotechnologies. PMID:24350771

  19. A rapid qualitative and quantitative evaluation of grape berries at various stages of development using Fourier-transform infrared spectroscopy and multivariate data analysis.

    PubMed

    Musingarabwi, Davirai M; Nieuwoudt, Hélène H; Young, Philip R; Eyéghè-Bickong, Hans A; Vivier, Melané A

    2016-01-01

    Fourier transform (FT) near-infrared (NIR) and attenuated total reflection (ATR) FT mid-infrared (MIR) spectroscopy were used to qualitatively and quantitatively analyse Vitis vinifera L. cv Sauvignon blanc grape berries. FT-NIR and ATR FT-MIR spectroscopy, coupled with spectral preprocessing and multivariate data analysis (MVDA), provided reliable methods to qualitatively assess berry samples at five distinct developmental stages: green, pre-véraison, véraison, post-véraison and ripe (harvest), without any prior metabolite extraction. Compared to NIR spectra, MIR spectra provided more reliable discrimination between the berry samples from the different developmental stages. Interestingly, ATR FT-MIR spectra from fresh homogenized berry samples proved more discriminatory than spectra from frozen homogenized berry samples. Different developmental stages were discriminated by principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). In order to generate partial least squares (PLS) models from the MIR/NIR spectral datasets; the major sugars (glucose and fructose) and organic acids (malic acid, succinic acid and tartaric acid) were separated and quantified by high performance liquid chromatography (HPLC) and the data used as a reference dataset. PLS regression was used to develop calibration models to predict the concentration of the major sugars and organic acids in the berry samples from different developmental stages. Our data show that infrared (IR) spectroscopy could provide a rapid, reproducible and cost-effective alternative to the chromatographic analysis of the sugar and organic acid composition of grape berries at various developmental stages, using small sample volumes and requiring limited sample preparation. This provides scope and support for the possible development of hand-held devices to assess quality parameters in field-settings in real-time and non-destructively using IR technologies. PMID:26212968

  20. Quantitative Analysis of Adulterations in Oat Flour by FT-NIR Spectroscopy, Incomplete Unbalanced Randomized Block Design, and Partial Least Squares

    PubMed Central

    Wang, Ning; Zhang, Xingxiang; Yu, Zhuo; Li, Guodong; Zhou, Bin

    2014-01-01

    This paper developed a rapid and nondestructive method for quantitative analysis of a cheaper adulterant (wheat flour) in oat flour by NIR spectroscopy and chemometrics. Reflectance FT-NIR spectra in the range of 4000 to 12000?cm?1 of 300 oat flour objects adulterated with wheat flour were measured. The doping levels of wheat flour ranged from 5% to 50% (w/w). To ensure the generalization performance of the method, both the oat and the wheat flour samples were collected from different producing areas and an incomplete unbalanced randomized block (IURB) design was performed to include the significant variations that may be encountered in future samples. Partial least squares regression (PLSR) was used to develop calibration models for predicting the levels of wheat flour. Different preprocessing methods including smoothing, taking second-order derivative (D2), and standard normal variate (SNV) transformation were investigated to improve the model accuracy of PLS. The root mean squared error of Monte Carlo cross-validation (RMSEMCCV) and root mean squared error of prediction (RMSEP) were 1.921 and 1.975 (%, w/w) by D2-PLS, respectively. The results indicate that NIR and chemometrics can provide a rapid method for quantitative analysis of wheat flour in oat flour. PMID:25143857

  1. Quantitative Metabolomic Profiling of Serum, Plasma, and Urine by 1H NMR Spectroscopy Discriminates between Patients with Inflammatory Bowel Disease and Healthy Individuals

    PubMed Central

    2012-01-01

    Serologic biomarkers for inflammatory bowel disease (IBD) have yielded variable differentiating ability. Quantitative analysis of a large number of metabolites is a promising method to detect IBD biomarkers. Human subjects with active Crohn’s disease (CD) and active ulcerative colitis (UC) were identified, and serum, plasma, and urine specimens were obtained. We characterized 44 serum, 37 plasma, and 71 urine metabolites by use of 1H NMR spectroscopy and “targeted analysis” to differentiate between diseased and non-diseased individuals, as well as between the CD and UC cohorts. We used multiblock principal component analysis and hierarchical OPLS-DA for comparing several blocks derived from the same “objects” (e.g., subject) to examine differences in metabolites. In serum and plasma of IBD patients, methanol, mannose, formate, 3-methyl-2-oxovalerate, and amino acids such as isoleucine were the metabolites most prominently increased, whereas in urine, maximal increases were observed for mannitol, allantoin, xylose, and carnitine. Both serum and plasma of UC and CD patients showed significant decreases in urea and citrate, whereas in urine, decreases were observed, among others, for betaine and hippurate. Quantitative metabolomic profiling of serum, plasma, and urine discriminates between healthy and IBD subjects. However, our results show that the metabolic differences between the CD and UC cohorts are less pronounced. PMID:22574726

  2. Quantitative NMR spectroscopy of complex technical mixtures using a virtual reference: chemical equilibria and reaction kinetics of formaldehyde-water-1,3,5-trioxane.

    PubMed

    Maiwald, Michael; Grützner, Thomas; Ströfer, Eckhard; Hasse, Hans

    2006-07-01

    Quantitative 1H NMR spectroscopy was used to study chemical equilibria and reaction kinetics of both the formation and decomposition of 1,3,5-trioxane in aqueous formaldehyde solutions. The reaction was homogeneously catalyzed with up to 0.10 g g(-1) sulfuric acid at temperatures between 360 and 383 K so that most of the experiments had to be carried out pressurized. The studied mixtures were complex due to the formation of methylene glycol and poly(oxymethylene) glycols in aqueous formaldehyde and the presence of considerable amounts of ionized species. Most common internal standards are decomposed by the hot sulfuric acid and external standards were not applicable using the flow NMR probe or pressurizable NMR sample tubes. Therefore, for the quantification of the small trioxane signals, a novel procedure was applied, in which electronically generated NMR signals were used as highly stable Virtual References (VR). The NMR decoupler channel with wave-form generator was used as the source of the reference signal, which was irradiated into the probe using the lock coil. Details on the experimental procedure are presented. It is shown that the presented method yields reliable quantitative reaction data for the complex studied mixtures. PMID:16773212

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

    SciTech Connect

    Prieto, P.; Morant, C.; Climent-Font, A.; Munoz, A.; Elizalde, E.; Sanz, J.M.

    2006-03-15

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

  4. Quantitative Study of Liver Magnetic Resonance Spectroscopy Quality at 3T Using Body and Phased Array Coils with Physical Analysis and Clinical Evaluation

    PubMed Central

    Xu, Li; Gu, Shiyong; Feng, Qianjin; Liang, Changhong; Xin, Sherman Xuegang

    2015-01-01

    This study aims to investigate the quality difference of short echo time (TE) breathhold 1H magnetic resonance spectroscopy (MRS) of the liver at 3.0T using the body and phased array coils, respectively. In total, 20 pairs of single-voxel proton spectra of the liver were acquired at 3.0T using the phased array and body coils as receivers. Consecutive stacks of breathhold spectra were acquired using the point resolved spectroscopy (PRESS) technique at a short TE of 30 ms and a repetition time (TR) of 1500 ms. The first spectroscopy sequence was “copied” for the second acquisition to ensure identical voxel positioning. The MRS prescan adjustments of shimming and water suppression, signal-to noise ratio (SNR), and major liver quantitative information were compared between paired spectra. Theoretical calculation of the SNR and homogeneity of the region of interest (ROI, 2 cm×2 cm×2 cm) using different coils loaded with 3D liver electromagnetic model of real human body was implemented in the theoretical analysis. The theoretical analysis showed that, inside the ROI, the SNR of the phase array coil was 2.8387 times larger than that of body coil and the homogeneity of the phase array coil and body coil was 80.10% and 93.86%, respectively. The experimental results showed excellent correlations between the paired data (all r > 0.86). Compared with the body coil group, the phased array group had slightly worse shimming effect and better SNR (all P values < .01). The discrepancy of the line width because of the different coils was approximately 0.8 Hz (0.00625 ppm). No significant differences of the major liver quantitative information of Cho/Lip2 height, Cho/Lip2 area, and lipid content were observed (all P values >0.05). The theoretical analysis and clinical experiment showed that the phased array coil was superior to the body coil with respect to 3.0T breathhold hepatic proton MRS. PMID:25881016

  5. Quantitative PVP mapping in PVDF hollow fiber membranes by using Raman spectroscopy coupled with spectral chemiometrics analysis

    NASA Astrophysics Data System (ADS)

    Dufour, E.; Gassara, S.; Petit, E.; Pochat-Bohatier, C.; Deratani, A.

    2015-07-01

    Fabrication of fouling resistant UF membranes requires the use of hydrophilic polymer additives that must be trapped in the polymer matrix during the phase separation processing. The knowledge of the polymeric additive distribution across the whole thickness should help to the design of more efficient membranes. This paper aims at developing a new methodology based on Raman microscopy spectroscopy owing to its high spatial resolution. A UF hollow fiber made from a blend of PVDF as polymer matrix and PVP as additive was chosen as a model membrane for this study. The PVP concentration profile along the cross-section radial axis was determined by using two ways of spectrum treatment including the analytical method by the peak intensity ratio calculation and a multivariate analysis with a partial least-squares regression model. The feasibility of the two approaches was discussed.

  6. Quantitative evaluation of multiple adulterants in roasted coffee by Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and chemometrics.

    PubMed

    Reis, Nádia; Franca, Adriana S; Oliveira, Leandro S

    2013-10-15

    The current study presents an application of Diffuse Reflectance Infrared Fourier Transform Spectroscopy for detection and quantification of fraudulent addition of commonly employed adulterants (spent coffee grounds, coffee husks, roasted corn and roasted barley) to roasted and ground coffee. Roasted coffee samples were intentionally blended with the adulterants (pure and mixed), with total adulteration levels ranging from 1% to 66% w/w. Partial Least Squares Regression (PLS) was used to relate the processed spectra to the mass fraction of adulterants and the model obtained provided reliable predictions of adulterations at levels as low as 1% w/w. A robust methodology was implemented that included the detection of outliers. High correlation coefficients (0.99 for calibration; 0.98 for validation) coupled with low degrees of error (1.23% for calibration; 2.67% for validation) confirmed that DRIFTS can be a valuable analytical tool for detection and quantification of adulteration in ground, roasted coffee. PMID:24054633

  7. Rapid evaluation and quantitative analysis of thyme, origano and chamomile essential oils by ATR-IR and NIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Schulz, Hartwig; Quilitzsch, Rolf; Krüger, Hans

    2003-12-01

    The essential oils obtained from various chemotypes of thyme, origano and chamomile species were studied by ATR/FT-IR as well as NIR spectroscopy. Application of multivariate statistics (PCA, PLS) in conjunction with analytical reference data leads to very good IR and NIR calibration results. For the main essential oil components (e.g. carvacrol, thymol, ?-terpinene, ?-bisabolol and ?-farnesene) standard errors are in the range of the applied GC reference method. In most cases the multiple coefficients of determination ( R2) are >0.97. Using the IR fingerprint region (900-1400 cm -1) a qualitative discrimination of the individual chemotypes is possible already by visual judgement without to apply any chemometric algorithms.The described rapid and non-destructive methods can be applied in industry to control very easily purifying, blending and redistillation processes of the mentioned essential oils.

  8. Quantitative Prediction of Beef Quality Using Visible and NIR Spectroscopy with Large Data Samples Under Industry Conditions

    NASA Astrophysics Data System (ADS)

    Qiao, T.; Ren, J.; Craigie, C.; Zabalza, J.; Maltin, Ch.; Marshall, S.

    2015-03-01

    It is well known that the eating quality of beef has a significant influence on the repurchase behavior of consumers. There are several key factors that affect the perception of quality, including color, tenderness, juiciness, and flavor. To support consumer repurchase choices, there is a need for an objective measurement of quality that could be applied to meat prior to its sale. Objective approaches such as offered by spectral technologies may be useful, but the analytical algorithms used remain to be optimized. For visible and near infrared (VISNIR) spectroscopy, Partial Least Squares Regression (PLSR) is a widely used technique for meat related quality modeling and prediction. In this paper, a Support Vector Machine (SVM) based machine learning approach is presented to predict beef eating quality traits. Although SVM has been successfully used in various disciplines, it has not been applied extensively to the analysis of meat quality parameters. To this end, the performance of PLSR and SVM as tools for the analysis of meat tenderness is evaluated, using a large dataset acquired under industrial conditions. The spectral dataset was collected using VISNIR spectroscopy with the wavelength ranging from 350 to 1800 nm on 234 beef M. longissimus thoracis steaks from heifers, steers, and young bulls. As the dimensionality with the VISNIR data is very high (over 1600 spectral bands), the Principal Component Analysis (PCA) technique was applied for feature extraction and data reduction. The extracted principal components (less than 100) were then used for data modeling and prediction. The prediction results showed that SVM has a greater potential to predict beef eating quality than PLSR, especially for the prediction of tenderness. The infl uence of animal gender on beef quality prediction was also investigated, and it was found that beef quality traits were predicted most accurately in beef from young bulls.

  9. Combining 1H NMR spectroscopy and multivariate regression techniques to quantitatively determine falsification of porcine heparin with bovine species.

    PubMed

    Monakhova, Yulia B; Diehl, Bernd W K

    2015-11-10

    (1)H NMR spectroscopy was used to distinguish pure porcine heparin and porcine heparin blended with bovine species and to quantify the degree of such adulteration. For multivariate modelling several statistical methods such as partial least squares regression (PLS), ridge regression (RR), stepwise regression with variable selection (SR), stepwise principal component regression (SPCR) were utilized for modeling NMR data of in-house prepared blends (n=80). The models were exhaustively validated using independent test and prediction sets. PLS and RR showed the best performance for estimating heparin falsification regarding its animal origin with the limit of detection (LOD) and root mean square error of validation (RMSEV) below 2% w/w and 1% w/w, respectively. Reproducibility expressed in coefficients of variation was estimated to be below 10% starting from approximately 5% w/w of bovine adulteration. Acceptable calibration model was obtained by SPCR, by its application range was limited, whereas SR is least recommended for heparin matrix. The developed method was found to be applicable also to heparinoid matrix (not purified heparin). In this case root mean square of prediction (RMSEP) and LOD were approximately 7% w/w and 8% w/w, respectively. The simple and cheap NMR method is recommended for screening of heparin animal origin in parallel with official NMR test of heparin authenticity and purity. PMID:26319747

  10. Quantitative Analysis of Carbon Content in Bituminous Coal by Laser-Induced Breakdown Spectroscopy Using UV Laser Radiation

    NASA Astrophysics Data System (ADS)

    Li, Xiongwei; Mao, Xianglei; Wang, Zhe; Richard, E. Russo

    2015-11-01

    The carbon content of bituminous coal samples was analyzed by laser-induced breakdown spectroscopy. The 266 nm laser radiation was utilized for laser ablation and plasma generation in air. The partial least square method and the dominant factor based PLS method were used to improve the measurement accuracy of the carbon content of coal. The results showed that the PLS model could achieve good measurement accuracy, and the dominant factor based PLS model could further improve the measurement accuracy. The coefficient of determination and the root-mean-square error of prediction of the PLS model were 0.97 and 2.19%, respectively; and those values for the dominant factor based PLS model were 0.99 and 1.51%, respectively. The results demonstrated that the 266 nm wavelength could accurately measure the carbon content of bituminous coal. supported by National Natural Science Foundation of China (No. 51276100) and the National Basic Research Program of China (973 Program) (No. 2013CB228501). The authors also thank the financial funding from the U. S. Department of Energy, Office of Basic Energy Sciences, Chemical Science Division at Lawrence Berkeley National Laboratory (No. 2013CB228501)

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

    SciTech Connect

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

    2011-03-20

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

  12. Quantitative determination of the oxidation state of iron in biotite using x-ray photoelectron spectroscopy: I. Calibration

    SciTech Connect

    Raeburn, S.P.; Ilton, E.S.; Veblen, D.R.

    1997-11-01

    X-ray photoelectron spectroscopy (XPS) analyses of Fe(III)/{Sigma}Fe were calibrated with nine single crystals of biotite of known Fe(III)/{Sigma}Fe content. Peak shape parameters for the component Fe{sup 2+} and Fe{sup 3+} Fe 3p peaks were obtained by a constrained lease squares fitting method that minimized the difference between Fe(III)/{Sigma}Fe determined by XPS and wet chemistry/electron microprobe (WCEM) analyses. Fe{sup 2+} and Fe{sup 3+} peak separation was estimated from the separation of minima in the second derivative of Fe 3p spectra. The single set of derived peak parameters yielded a good linear correlation (r = 0.87) between XPS and WCEM values over the sample displaying progressive oxidation during XPS analysis resulted in Fe{sup 2} and Fe{sup 3+} component peak shapes largely consistent with the constrained least squares fitting methods. Beam damage, which appeared to be restricted to three single crystals with low {Sigma}Fe, low Fe/Mg, and high Fe(II)/{Sigma}Fe, caused increases in Fe(III)/{Sigma}Fe that were proportional to the duration of sample exposure. 60 refs., 6 figs., 7 tabs.

  13. 2D IR Spectroscopy using Four-Wave Mixing, Pulse Shaping, and IR Upconversion: A Quantitative Comparison

    PubMed Central

    Rock, William; Li, Yun-Liang; Pagano, Philip; Cheatum, Christopher M.

    2013-01-01

    Recent technological advances have led to major changes in the apparatuses used to collect 2D IR spectra. Pulse shaping offers several advantages including rapid data collection, inherent phase stability, and phase cycling capabilities. Visible array detection via upconversion allows the use of visible detectors that are cheaper, faster, more sensitive, and less noisy than IR detectors. However, despite these advantages, many researchers are reluctant to implement these technologies. Here we present a quantitative study of the S/N of 2D IR spectra collected with a traditional four-wave mixing (FWM) apparatus, with a pulse shaping apparatus, and with visible detection via upconversion to address the question of whether or not weak chromophores at low concentrations are still accessible with such an apparatus. We find that the enhanced averaging capability of the pulse shaping apparatus enables the detection of small signals that would be challenging to measure even with the traditional FWM apparatus, and we demonstrate this ability on a sample of cyanylated dihydrofolate reductase (DHFR). PMID:23687988

  14. Gannet: A Batch-Processing Tool for the Quantitative Analysis of Gamma-Aminobutyric Acid–Edited MR Spectroscopy Spectra

    PubMed Central

    Edden, Richard A.E.; Puts, Nicolaas A.J.; Harris, Ashley D.; Barker, Peter B.; Evans, C. John

    2014-01-01

    Purpose The purpose of this study is to describe the Gannet toolkit for the quantitative batch analysis of gamma-aminobutyric acid (GABA) -edited MRS data. Materials and Methods Using MEGA-PRESS editing and standard acquisition parameters, four MEGA-PRESS spectra were acquired in three brain regions in 10 healthy volunteers. These 120 datasets were processed without user intervention with Gannet, a Matlab-based tool that takes raw time-domain data input, processes it to generate the frequency-domain edited spectrum, and applies a simple modeling procedure to estimate GABA concentration relative to the creatine or, if provided, the unsuppressed water signal. A comparison of four modeling approaches is also presented. Results All data were successfully processed by Gannet. Coefficients of variation across subjects ranged from 11% for the occipital region to 17% for the dorsolateral prefrontal region. There was no clear difference in fitting performance between the simple Gaussian model used by Gannet and the other more complex models presented. Conclusion Gannet, the GABA Analysis Toolkit, can be used to process and quantify GABA-edited MRS spectra without user intervention. PMID:25548816

  15. 2D IR spectroscopy using four-wave mixing, pulse shaping, and IR upconversion: a quantitative comparison.

    PubMed

    Rock, William; Li, Yun-Liang; Pagano, Philip; Cheatum, Christopher M

    2013-07-25

    Recent technological advances have led to major changes in the apparatuses used to collect 2D IR spectra. Pulse shaping offers several advantages including rapid data collection, inherent phase stability, and phase-cycling capabilities. Visible array detection via upconversion allows the use of visible detectors that are cheaper, faster, more sensitive, and less noisy than IR detectors. However, despite these advantages, many researchers are reluctant to implement these technologies. Here we present a quantitative study of the S/N of 2D IR spectra collected with a traditional four-wave mixing (FWM) apparatus, with a pulse shaping apparatus, and with visible detection via upconversion to address the question of whether weak chromophores at low concentrations are still accessible with such an apparatus. We find that the enhanced averaging capability of the pulse shaping apparatus enables the detection of small signals that would be challenging to measure even with the traditional FWM apparatus, and we demonstrate this ability on a sample of cyanylated dihydrofolate reductase. PMID:23687988

  16. QUANTITATIVE SPECTROSCOPY OF BLUE SUPERGIANT STARS IN THE DISK OF M81: METALLICITY, METALLICITY GRADIENT, AND DISTANCE

    SciTech Connect

    Kudritzki, Rolf-Peter; Urbaneja, Miguel A.; Gazak, Zachary; Bresolin, Fabio; Przybilla, Norbert; Gieren, Wolfgang; Pietrzynski, Grzegorz E-mail: urbaneja@ifa.hawaii.edu E-mail: bresolin@ifa.hawaii.edu E-mail: wgieren@astro-udec.cl

    2012-03-01

    The quantitative spectral analysis of low-resolution ({approx}5 A) Keck LRIS spectra of blue supergiants in the disk of the giant spiral galaxy M81 is used to determine stellar effective temperatures, gravities, metallicities, luminosities, interstellar reddening, and a new distance using the flux-weighted gravity-luminosity relationship. Substantial reddening and extinction are found with E(B - V) ranging between 0.13 and 0.38 mag and an average value of 0.26 mag. The distance modulus obtained after individual reddening corrections is 27.7 {+-} 0.1 mag. The result is discussed with regard to recently measured tip of the red giant branch and Cepheid distances. The metallicities (based on elements such as iron, titanium, magnesium) are supersolar ( Almost-Equal-To 0.2 dex) in the inner disk (R {approx}< 5 kpc) and slightly subsolar ( Almost-Equal-To - 0.05 dex) in the outer disk (R {approx}> 10 kpc) with a shallow metallicity gradient of 0.034 dex kpc{sup -1}. The comparison with published oxygen abundances of planetary nebulae and metallicities determined through fits of Hubble Space Telescope color-magnitude diagrams indicates a late metal enrichment and a flattening of the abundance gradient over the last 5 Gyr. This might be the result of gas infall from metal-rich satellite galaxies. Combining these M81 metallicities with published blue supergiant abundance studies in the Local Group and the Sculptor Group, a galaxy mass-metallicity relationship based solely on stellar spectroscopic studies is presented and compared with recent studies of Sloan Digital Sky Survey star-forming galaxies.

  17. On-line quantitative monitoring of liquid-liquid extraction of Lonicera japonica and Artemisia annua using near-infrared spectroscopy and chemometrics

    PubMed Central

    Wu, Sha; Jin, Ye; Liu, Qian; Liu, Qi-an; Wu, Jianxiong; Bi, Yu-an; Wang, Zhengzhong; Xiao, Wei

    2015-01-01

    Background: Liquid-liquid extraction of Lonicera japonica and Artemisia annua (JQ) plays a significant role in manufacturing Reduning injection. Many process parameters may influence liquid-liquid extraction and cause fluctuations in product quality. Objective: To develop a near-infrared (NIR) spectroscopy method for on-line monitoring of liquid-liquid extraction of JQ. Materials and Methods: Eleven batches of JQ extraction solution were obtained, ten for building quantitative models and one for assessing the predictive accuracy of established models. Neochlorogenic acid (NCA), chlorogenic acid (CA), cryptochlorogenic acid (CCA), isochlorogenic acid B (ICAB), isochlorogenic acid A (ICAA), isochlorogenic acid C (ICAC) and soluble solid content (SSC) were selected as quality control indicators, and measured by reference methods. NIR spectra were collected in transmittance mode. After selecting the spectral sub-ranges, optimizing the spectral pretreatment and neglecting outliers, partial least squares regression models were built to predict the content of indicators. The model performance was evaluated by the coefficients of determination (R2), the root mean square errors of prediction (RMSEP) and the relative standard error of prediction (RSEP). Results: For NCA, CA, CCA, ICAB, ICAA, ICAC and SSC, R2 was 0.9674, 0.9704, 0.9641, 0.9514, 0.9436, 0.9640, 0.9809, RMSEP was 0.0280, 0.2913, 0.0710, 0.0590, 0.0815, 0.1506, 1.167, and RSEP was 2.32%, 4.14%, 3.86%, 5.65%, 7.29%, 6.95% and 4.18%, respectively. Conclusion: This study demonstrated that NIR spectroscopy could provide good predictive ability in monitoring of the content of quality control indicators in liquid-liquid extraction of JQ. PMID:26246744

  18. Direct Analysis of Free and Sulfite-Bound Carbonyl Compounds in Wine by Two-Dimensional Quantitative Proton and Carbon Nuclear Magnetic Resonance Spectroscopy.

    PubMed

    Nikolantonaki, Maria; Magiatis, Prokopios; Waterhouse, Andrew L

    2015-11-01

    Recent developments that have accelerated 2D NMR methods and improved quantitation have made these methods accessible analytical procedures, and the large signal dispersion allows for the analysis of complex samples. Few natural samples are as complex as wine, so the application to challenges in wine analysis look promising. The analysis of carbonyl compounds in wine, key oxidation products, is complicated by a multitude of kinetically reversible adducts, such as acetals and sulfonates, so that sample preparation steps can generate complex interferences. These challenges could be overcome if the compounds could be quantified in situ. Here, two-dimensional ((1)H-(1)H) homonuclear and heteronuclear ((13)C-(1)H) single quantum correlations (correlation spectroscopy, COSY, and heteronuclear single quantum coherence, HSQC) nuclear magnetic resonance spectra of undiluted wine samples were observed at natural abundance. These techniques achieve simultaneous direct identification and quantitation of acetaldehyde, pyruvic acid, acetoin, methylglyoxal, and ?-ketoglutaric acid in wine with only a small addition of D2O. It was also possible to observe and sometimes quantify the sulfite, hydrate, and acetal forms of the carbonyl compounds. The accuracy of the method was tested in wine samples by spiking with a mixture of all analytes at different concentrations. The method was applied to 15 wine samples of various vintages and grape varieties. The application of this method could provide a powerful tool to better understand the development, evolution, and perception of wine oxidation and insight into the impact of these sulfite bound carbonyls on antimicrobial and antioxidant action by SO2. PMID:26348554

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

    PubMed

    Edwards, C S; Christensen, P R

    2013-04-10

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

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

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

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

  1. Time-Resolved Quantitative Measurement of OH HO2 and CH2O in Fuel Oxidation Reactions by High Resolution IR Absorption Spectroscopy.

    SciTech Connect

    Huang, Haifeng; Rotavera, Brandon; Taatjes, Craig A.

    2014-08-01

    Combined with a Herriott-type multi-pass slow flow reactor, high-resolution differential direct absorption spectroscopy has been used to probe, in situ and quantitatively, hydroxyl (OH), hydroperoxy (HO 2 ) and formaldehyde (CH 2 O) molecules in fuel oxidation reactions in the reactor, with a time resolution of about 1 micro-second. While OH and CH 2 O are probed in the mid-infrared (MIR) region near 2870nm and 3574nm respectively, HO 2 can be probed in both regions: near-infrared (NIR) at 1509nm and MIR at 2870nm. Typical sensitivities are on the order of 10 10 - 10 11 molecule cm -3 for OH at 2870nm, 10 11 molecule cm -3 for HO 2 at 1509nm, and 10 11 molecule cm -3 for CH 2 O at 3574nm. Measurements of multiple important intermediates (OH and HO 2 ) and product (CH 2 O) facilitate to understand and further validate chemical mechanisms of fuel oxidation chemistry.

  2. Reduced cortical microvascular oxygenation in multiple sclerosis: a blinded, case-controlled study using a novel quantitative near-infrared spectroscopy method

    NASA Astrophysics Data System (ADS)

    Yang, Runze; Dunn, Jeff F.

    2015-11-01

    Hypoxia (low oxygen) is associated with many brain disorders as well as inflammation, but the lack of widely available technology has limited our ability to study hypoxia in human brain. Multiple sclerosis (MS) is a poorly understood neurological disease with a significant inflammatory component which may cause hypoxia. We hypothesized that if hypoxia were to occur, there should be reduced microvascular hemoglobin saturation (StO2). In this study, we aimed to determine if reduced StO2 can be detected in MS using frequency domain near-infrared spectroscopy (fdNIRS). We measured fdNIRS data in cortex and assessed disability of 3 clinical isolated syndrome (CIS), 72 MS patients and 12 controls. Control StO2 was 63.5?±?3% (mean?±?SD). In MS patients, 42% of StO2 values were more than 2?×?SD lower than the control mean. There was a significant relationship between StO2 and clinical disability. A reduced microvascular StO2 is supportive (although not conclusive) that there may be hypoxic regions in MS brain. This is the first study showing how quantitative NIRS can be used to detect reduced StO2 in patients with MS, opening the door to understanding how microvascular oxygenation impacts neurological conditions.

  3. Reduced cortical microvascular oxygenation in multiple sclerosis: a blinded, case-controlled study using a novel quantitative near-infrared spectroscopy method

    PubMed Central

    Yang, Runze; Dunn, Jeff F.

    2015-01-01

    Hypoxia (low oxygen) is associated with many brain disorders as well as inflammation, but the lack of widely available technology has limited our ability to study hypoxia in human brain. Multiple sclerosis (MS) is a poorly understood neurological disease with a significant inflammatory component which may cause hypoxia. We hypothesized that if hypoxia were to occur, there should be reduced microvascular hemoglobin saturation (StO2). In this study, we aimed to determine if reduced StO2 can be detected in MS using frequency domain near-infrared spectroscopy (fdNIRS). We measured fdNIRS data in cortex and assessed disability of 3 clinical isolated syndrome (CIS), 72 MS patients and 12 controls. Control StO2 was 63.5?±?3% (mean?±?SD). In MS patients, 42% of StO2 values were more than 2?×?SD lower than the control mean. There was a significant relationship between StO2 and clinical disability. A reduced microvascular StO2 is supportive (although not conclusive) that there may be hypoxic regions in MS brain. This is the first study showing how quantitative NIRS can be used to detect reduced StO2 in patients with MS, opening the door to understanding how microvascular oxygenation impacts neurological conditions. PMID:26563581

  4. Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Wehling, Randy L.

    Infrared (IR) spectroscopy refers to measurement of the absorption of different frequencies of IR radiation by foods or other solids, liquids, or gases. IR spectroscopy began in 1800 with an experiment by Herschel. When he used a prism to create a spectrum from white light and placed a thermometer at a point just beyond the red region of the spectrum, he noted an increase in temperature. This was the first observation of the effects of IR radiation. By the 1940s, IR spectroscopy had become an important tool used by chemists to identify functional groups in organic compounds. In the 1970s, commercial near-IR reflectance instruments were introduced that provided rapid quantitative determinations of moisture, protein, and fat in cereal grains and other foods. Today, IR spectroscopy is used widely in the food industry for both qualitative and quantitative analysis of ingredients and finished foods.

  5. Evaluation of Early Osteochondral Defect Repair in a Rabbit Model Utilizing Fourier Transform–Infrared Imaging Spectroscopy, Magnetic Resonance Imaging, and Quantitative T2 Mapping

    PubMed Central

    Kim, Minwook; Foo, Li F.; Uggen, Christopher; Lyman, Steven; Ryaby, James T.; Moynihan, Daniel P.; Grande, Daniel Anthony; Potter, Hollis G.

    2010-01-01

    Context Evaluation of the morphology and matrix composition of repair cartilage is a critical step toward understanding the natural history of cartilage repair and efficacy of potential therapeutics. In the current study, short-term articular cartilage repair (3 and 6 weeks) was evaluated in a rabbit osteochondral defect model treated with thrombin peptide (TP-508) using magnetic resonance imaging (MRI), quantitative T2 mapping, and Fourier transform–infrared imaging spectroscopy (FT-IRIS). Methods Three-mm-diameter osteochondral defects were made in the rabbit trochlear groove and filled with either TP-508 plus poly-lactoglycolidic acid microspheres or poly-lactoglycolidic acid microspheres alone (placebo). Repair tissue and adjacent normal cartilage were evaluated at 3 and 6 weeks postdefect creation. Intact knees were evaluated by magnetic resonance imaging for repair morphology, and with quantitative T2 mapping to assess collagen orientation. Histological sections were evaluated by FT-IRIS for parameters that reflect collagen quantity and quality, as well as proteoglycan (PG) content. Results and Conclusion There was no significant difference in volume of repair tissue at either time point. At 6 weeks, placebo repair tissue demonstrated longer T2 values (p?

  6. UV-Vis Reflection-Absorption Spectroscopy at air-liquid interfaces.

    PubMed

    Rubia-Payá, Carlos; de Miguel, Gustavo; Martín-Romero, María T; Giner-Casares, Juan J; Camacho, Luis

    2015-11-01

    UV-Visible Reflection-Absorption Spectroscopy (UVRAS) technique is reviewed with a general perspective on fundamental and applications. UVRAS is formally identical to IR Reflection-Absorption Spectroscopy (IRRAS), and therefore, the methodology developed for this IR technique can be applied in the UV-visible region. UVRAS can be applied to air-solid, air-liquid or liquid-liquid interfaces. This review focuses on the use of UVRAS for studying Langmuir monolayers. We introduce the theoretical framework for a successful understanding of the UVRAS data, and we illustrate the usage of this data treatment to a previous study from our group comprising an amphiphilic porphyrin. For ultrathin films with a thickness of few nm, UVRAS produces positive or negative bands when p-polarized radiation is used, depending on the incidence angle and the orientation of dipole absorption. UVRAS technique provides highly valuable information on tilt of chromophores at the air-liquid interface, and moreover allows the determination of optical parameters. We propose UVRAS as a powerful technique to investigate the in situ optical properties of Langmuir monolayers. PMID:26385430

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

    PubMed

    Peerapattana, Jomjai; Otsuka, Kuniko; Otsuka, Makoto

    2013-07-01

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

  8. Chiroptical Spectroscopy

    NASA Astrophysics Data System (ADS)

    Gurst, Jerome E.

    1995-09-01

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

  9. Evolution of Instrumentation for UV-Visible Spectrophotometry. Part I.

    ERIC Educational Resources Information Center

    Altemose, Ines R.

    1986-01-01

    Traces the development of instruments used in spectrophotometry. Discusses how spectrophotometric measurements are made. Describes the color comparator, the filter photometer, and the spectrophotometer. Outlines the evolution of optical systems, including light sources, the monochromator, the photodetector, double-beam optics, and split-beam…

  10. Honeywell's Compact, Wide-angle Uv-visible Imaging Sensor

    NASA Technical Reports Server (NTRS)

    Pledger, D.; Billing-Ross, J.

    1993-01-01

    Honeywell is currently developing the Earth Reference Attitude Determination System (ERADS). ERADS determines attitude by imaging the entire Earth's limb and a ring of the adjacent star field in the 2800-3000 A band of the ultraviolet. This is achieved through the use of a highly nonconventional optical system, an intensifier tube, and a mega-element CCD array. The optics image a 30 degree region in the center of the field, and an outer region typically from 128 to 148 degrees, which can be adjusted up to 180 degrees. Because of the design employed, the illumination at the outer edge of the field is only some 15 percent below that at the center, in contrast to the drastic rolloffs encountered in conventional wide-angle sensors. The outer diameter of the sensor is only 3 in; the volume and weight of the entire system, including processor, are 1000 cc and 6 kg, respectively.

  11. Comparison of photoacoustic spectroscopy, conventional absorption spectroscopy, and potentiometry as probes of lanthanide speciation

    SciTech Connect

    Torres, R.A.; Palmer, C.E.A.; Baisden, P.A.; Russo, R.E.; Silva, R.J. )

    1990-02-01

    The authors measured the stability constants of praseodymium acetate and oxydiacetate complexes by laser-induced photoacoustic spectroscopy, conventional UV-visible absorption spectroscopy, and pH titration. For the spectroscopic studies, changes in the free Pr absorption peaks at 468 and 481 nm were monitored at varying ligand concentrations. The total Pr concentration was 1 {times} 10{sup {minus}4} M in solutions used for the photoacoustic studies and 0.02 M for conventional spectroscopy. For the pH titrations, we used solutions whose Pr concentrations varied from 5 {times} 10{sup {minus}3} to 5 {times} 10{sup {minus}2} M, with total ligand-to-metal ratios ranging from 1 to 10. A comparison of the results obtained by the three techniques demonstrates that photoacoustic spectroscopy can give the same information about metal-ligand speciation as more conventional methods. It is particularly suited to those situations where the other techniques are insensitive because of limited metal concentrations.

  12. Phthalocyanine identification in paintings by reflectance spectroscopy. A laboratory and in situ study

    NASA Astrophysics Data System (ADS)

    Poldi, G.; Caglio, S.

    2013-06-01

    The importance of identifying pigments using non invasive (n.i.) analyses has gained increasing importance in the field of spectroscopy applied to art conservation and art studies. Among the large set of pigments synthesized and marketed during 20th century, surely phthalocyanine blue and green pigments occupy an important role in the field of painting (including restoration) and printing, thanks to their characteristics like brightness and fastness. This research focused on the most used phthalocyanine blue (PB15:1 and PB15:3) and green pigments (PG7), and on the possibility to identify these organic compounds using a methodology like reflectance spectroscopy in the UV, visible and near IR range (UV-vis-NIR RS), performed easily through portable instruments. Laboratory tests and three examples carried out on real paintings are discussed.

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

    SciTech Connect

    Lehnert, N.; Sage, J. T.; Silvernail, N.; Scheidt, W. R.; Alp, E. E.; Sturhahn, W.; Zhao, J.

    2010-01-01

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

  14. Oriented Single-Crystal Nuclear Resonance Vibrational Spectroscopy of [Fe(TPP)(MI)(NO)]: Quantitative Assessment of the trans Effect of NO

    PubMed Central

    Silvernail, Nathan; Alp, E. Ercan; Sturhahn, Wolfgang; Zhao, Jiyong

    2010-01-01

    This paper presents oriented single-crystal Nuclear Resonance Vibrational Spectroscopy (NRVS) data for the six-coordinate (6C) ferrous heme-nitrosyl model complex [57Fe(TPP)(MI)(NO)] (1; TPP2? = tetraphenylporphyrin dianion; MI = 1-methylimidazole). The availability of these data enables for the first time the detailed simulation of the complete NRVS data, including the porphyrin-based vibrations, of a 6C ferrous heme-nitrosyl, using our quantum chemistry centered normal coordinate analysis (QCC-NCA). Importantly, the Fe-NO stretch is split by interaction with a porphyrin-based vibration into two features, observed at 437 and 472 cm?1. The 437 cm?1 feature is strongly out-of-plane (oop) polarized and shows an 15N18O isotope shift of 8 cm?1, and is therefore assigned to ?(Fe-NO). The admixture of Fe-N-O bending character is small. Main contributions to the Fe-N-O bend are observed in the 520 – 580 cm?1 region, distributed over a number of in-plane (ip) polarized porphyrin-based vibrations. The main component, assigned to ?ip(Fe-N-O), is identified with the feature at 563 cm?1. The Fe-N-O bend also shows strong mixing with the Fe-NO stretching internal coordinate, as evidenced by the oop NRVS intensity in the 520 – 580 cm?1 region. Very accurate normal mode descriptions of ?(Fe-NO) and ?ip(Fe-N-O) have been obtained in this study. These results contradict previous interpretations of the vibrational spectra of 6C ferrous heme-nitrosyls where the higher energy feature at ~550 cm?1 had usually been associated with ?(Fe-NO). Furthermore, these results provide key insight into NO binding to ferrous heme active sites in globins and other heme proteins, in particular with respect to (a) the effect of hydrogen bonding to the coordinated NO, and (b) changes in heme dynamics upon NO coordination. [Fe(TPP)(MI)(NO)] constitutes an excellent model system for ferrous NO adducts of myoglobin (Mb) mutants where the distal histidine (His64) has been removed. Comparison to the reported vibrational data for wild-type (wt) Mb-NO then shows that the effect of H-bonding to coordinated NO is weak, and mostly leads to a polarization of the ?/?* orbitals of bound NO. In addition, the observation that ?ip(Fe-N-O) does not correlate well with ?(N-O) can be traced back to the very mixed nature of this mode. The Fe-N(imidazole) stretching frequency is observed at 149 cm?1 in [Fe(TPP)(MI)(NO)], and spectral changes upon NO binding to five-coordinate ferrous heme active sites are discussed. The obtained high-quality force constants for the Fe-NO and N-O bonds of 2.57 and 11.55 mdyn/Å can further be compared to those of corresponding 5C species, which allows for a quantitative analysis of the ? trans interaction between the proximal imidazole (His) ligand and NO. This is key for the activation of the NO sensor soluble guanylate cyclase. Finally, DFT methods are calibrated against the experimentally determined vibrational properties of the Fe-N-O subunit in 1. DFT is in fact incapable of reproducing the vibrational energies and normal mode descriptions of the Fe-N-O unit well, and thus, DFT-based predictions of changes in vibrational properties upon heme-modification or other perturbations of these 6C complexes have to be treated with caution. PMID:20586416

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

    PubMed

    Lehnert, Nicolai; Sage, J Timothy; Silvernail, Nathan; Scheidt, W Robert; Alp, E Ercan; Sturhahn, Wolfgang; Zhao, Jiyong

    2010-08-01

    This paper presents oriented single-crystal Nuclear Resonance Vibrational Spectroscopy (NRVS) data for the six-coordinate (6C) ferrous heme-nitrosyl model complex [(57)Fe(TPP)(MI)(NO)] (1; TPP(2-) = tetraphenylporphyrin dianion; MI = 1-methylimidazole). The availability of these data enables for the first time the detailed simulation of the complete NRVS data, including the porphyrin-based vibrations, of a 6C ferrous heme-nitrosyl, using our quantum chemistry centered normal coordinate analysis (QCC-NCA). Importantly, the Fe-NO stretch is split by interaction with a porphyrin-based vibration into two features, observed at 437 and 472 cm(-1). The 437 cm(-1) feature is strongly out-of-plane (oop) polarized and shows a (15)N(18)O isotope shift of 8 cm(-1) and is therefore assigned to nu(Fe-NO). The admixture of Fe-N-O bending character is small. Main contributions to the Fe-N-O bend are observed in the 520-580 cm(-1) region, distributed over a number of in-plane (ip) polarized porphyrin-based vibrations. The main component, assigned to delta(ip)(Fe-N-O), is identified with the feature at 563 cm(-1). The Fe-N-O bend also shows strong mixing with the Fe-NO stretching internal coordinate, as evidenced by the oop NRVS intensity in the 520-580 cm(-1) region. Very accurate normal mode descriptions of nu(Fe-NO) and delta(ip)(Fe-N-O) have been obtained in this study. These results contradict previous interpretations of the vibrational spectra of 6C ferrous heme-nitrosyls where the higher energy feature at approximately 550 cm(-1) had usually been associated with nu(Fe-NO). Furthermore, these results provide key insight into NO binding to ferrous heme active sites in globins and other heme proteins, in particular with respect to (a) the effect of hydrogen bonding to the coordinated NO and (b) changes in heme dynamics upon NO coordination. [Fe(TPP)(MI)(NO)] constitutes an excellent model system for ferrous NO adducts of myoglobin (Mb) mutants where the distal histidine (His64) has been removed. Comparison to the reported vibrational data for wild-type (wt) Mb-NO then shows that the effect of H bonding to the coordinated NO is weak and mostly leads to a polarization of the pi/pi* orbitals of bound NO. In addition, the observation that delta(ip)(Fe-N-O) does not correlate well with nu(N-O) can be traced back to the very mixed nature of this mode. The Fe-N(imidazole) stretching frequency is observed at 149 cm(-1) in [Fe(TPP)(MI)(NO)], and spectral changes upon NO binding to five-coordinate ferrous heme active sites are discussed. The obtained high-quality force constants for the Fe-NO and N-O bonds of 2.57 and 11.55 mdyn/A can further be compared to those of corresponding 5C species, which allows for a quantitative analysis of the sigma trans interaction between the proximal imidazole (His) ligand and NO. This is key for the activation of the NO sensor soluble guanylate cyclase. Finally, DFT methods are calibrated against the experimentally determined vibrational properties of the Fe-N-O subunit in 1. DFT is in fact incapable of reproducing the vibrational energies and normal mode descriptions of the Fe-N-O unit well, and thus, DFT-based predictions of changes in vibrational properties upon heme modification or other perturbations of these 6C complexes have to be treated with caution. PMID:20586416

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

    PubMed

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

    2014-09-01

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

  17. In-situ Optical Spectroscopy Investigation of Water and Its influence on Forsterite Transformation in Supercritical CO2

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Thompson, C. J.; Joly, A. G.; Sklarew, D. S.; Poindexter, L.; Rosso, K. M.

    2009-12-01

    Carbon capture and sequestration (CCS) from coal/gas-burning power plants is currently viewed as one of the most promising technologies for mitigating green house gas emissions. This strategy involves injection of supercritical CO2 (scCO2) into deep geological formations such as depleted oil and gas reservoirs and deep saline aquifers. The feasibility of this approach and the ultimate fate of the stored CO2 are determined by the interactions between scCO2, various minerals in the rock formations, and the host fluids. Currently, there is only limited knowledge about both the thermodynamic and kinetic aspects of the physical and chemical processes that occur between scCO2 and relevant minerals, such as metal silicates and metal aluminosilicates, and the role of water activity for catalyzing mineral transformation reactions. In this work, we have developed a modular in situ optical spectroscopic platform that integrates a scCO2 generation and manipulation system with an array of optical and laser spectroscopies including UV-visible, IR, Raman and laser fluorescence spectroscopy. We have used the system to study i) the dissolution and quantification of H2O/D2O in scCO2 and ii) interaction between scCO2 and a model metal silicate, forsterite (Mg2SiO4), and the effects of the presence of water under variable pressure, temperature and water content. Our results showed that H2O and D2O have unique IR spectral features over a broad spectral range from 700 cm-1 to ~ 2900 cm-1 in scCO2 and their concentrations are directly proportional to the characteristic IR bands that correspond to their stretching (D2O) and bending frequencies (both D2O and H2O). These bands offer a unique spectroscopic signature useful for qualitative and quantitative analysis of the properties and reactivity of small amounts of H2O in scCO2.

  18. Quantitative solid-state analysis of three solid forms of ranitidine hydrochloride in ternary mixtures using Raman spectroscopy and X-ray powder diffraction.

    PubMed

    Chieng, Norman; Rehder, Sönke; Saville, Dorothy; Rades, Thomas; Aaltonen, Jaakko

    2009-01-15

    The aim of the study was to develop a reliable quantification procedure for mixtures of three solid forms of ranitidine hydrochloride using X-ray powder diffraction (XRPD) and Raman spectroscopy combined with multivariate analysis. The effect of mixing methods of the calibration samples on the calibration model quality was also investigated. Thirteen ternary samples of form 1, form 2 and the amorphous form of ranitidine hydrochloride were prepared in triplicate to build a calibration model. The ternary samples were prepared by three mixing methods (a) manual mixing (MM) and ball mill mixing (BM) using two (b) 5 mm (BM5) or (c) 12 mm (BM12) balls for 1 min. The samples were analyzed with XRPD and Raman spectroscopy. Principal component analysis (PCA) was used to study the effect of mixing method, while partial least squares (PLS) regression was used to build the quantification models. PCA score plots showed that, in general, BM12 resulted in the narrowest sample clustering indicating better sample homogeneity. In the quantification models, the number of PLS factors was determined using cross-validation and the models were validated using independent test samples with known concentrations. Multiplicative scattering correction (MSC) without scaling gave the best PLS regression model for XPRD, and standard normal variate (SNV) transformation with centering gave the best model for Raman spectroscopy. Using PLS regression, the root mean square error of prediction (RMSEP) values of the best models were 5.0-6.9% for XRPD and 2.5-4.5% for Raman spectroscopy. XRPD and Raman spectroscopy in combination with PLS regression can be used to quantify the amount of single components in ternary mixtures of ranitidine hydrochloride solid forms. Raman spectroscopy gave better PLS regression models than XRPD, allowing a more accurate quantification. PMID:19081220

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

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  20. Multi-wavelength spectroscopy of oriented erythrocytes

    NASA Astrophysics Data System (ADS)

    Serebrennikova, Yulia M.; Garcia-Rubio, Luis H.; Smith, Jennifer M.; Huffman, Debra E.

    2010-02-01

    Accurate characterization of the optical properties of erythrocytes is essential for the applications in optical biomedicine, in particular, for diagnosis of blood related diseases. The observed optical properties strongly depend on the erythrocyte's size, hemoglobin composition and orientation relative to the incident light. We explored the effect of orientation on the absorption and scattering properties of erythrocytes suspended in saline using UV-visible spectroscopy and theoretical predictive modeling based on anomalous diffraction approximation. We demonstrate that the orientation of erythrocytes in dilute saline suspensions is not random and produces consistent spectral pattern. Numerical analysis showed that the multi-wavelength absorption and scattering properties of erythrocytes in dilute suspensions can be accurately described with two orientation populations. These orientation populations with respect to the incident light are face-on incidence and edge-on incidence. The variances of the orientation angles for each population are less than 15 degrees and the relative proportions of the two populations strongly depend on the number density of the erythrocytes in suspensions. Further, the identified orientation populations exhibit different sensitivities to the changes in the compositional and morphological properties of erythrocytes. The anomalous diffraction model based on these orientation populations predicts the absorption and scattering properties of erythrocytes with accuracy greater than 99%. Establishment of the optical properties of normal erythrocytes allows for detection of the disease induced changes in the erythrocyte spectral signatures.

  1. Near-infrared Raman spectroscopy to detect anti-Toxoplasma gondii antibody in blood sera of domestic cats: quantitative analysis based on partial least-squares multivariate statistics

    NASA Astrophysics Data System (ADS)

    Duarte, Janaína; Pacheco, Marcos T. T.; Villaverde, Antonio Balbin; Machado, Rosangela Z.; Zângaro, Renato A.; Silveira, Landulfo

    2010-07-01

    Toxoplasmosis is an important zoonosis in public health because domestic cats are the main agents responsible for the transmission of this disease in Brazil. We investigate a method for diagnosing toxoplasmosis based on Raman spectroscopy. Dispersive near-infrared Raman spectra are used to quantify anti-Toxoplasma gondii (IgG) antibodies in blood sera from domestic cats. An 830-nm laser is used for sample excitation, and a dispersive spectrometer is used to detect the Raman scattering. A serological test is performed in all serum samples by the enzyme-linked immunosorbent assay (ELISA) for validation. Raman spectra are taken from 59 blood serum samples and a quantification model is implemented based on partial least squares (PLS) to quantify the sample's serology by Raman spectra compared to the results provided by the ELISA test. Based on the serological values provided by the Raman/PLS model, diagnostic parameters such as sensitivity, specificity, accuracy, positive prediction values, and negative prediction values are calculated to discriminate negative from positive samples, obtaining 100, 80, 90, 83.3, and 100%, respectively. Raman spectroscopy, associated with the PLS, is promising as a serological assay for toxoplasmosis, enabling fast and sensitive diagnosis.

  2. Corrole-ferrocene and corrole-anthraquinone dyads: synthesis, spectroscopy and photochemistry.

    PubMed

    Kandhadi, Jaipal; Yeduru, Venkatesh; Bangal, Prakriti R; Giribabu, Lingamallu

    2015-10-01

    Two different donor-acceptor systems based on corrole-ferrocene and corrole-anthraquinone having the 'Olefin Bridge' at the ?-pyrrole position have been designed and synthesized. Both the dyads corrole-ferrocene () and corrole-anthraquinone () are characterized by elemental analysis, ESI-MS, (1)H NMR, UV-Visible, fluorescence spectroscopies (steady-state, femtosecond time-resolved), femtosecond transient absorption spectroscopy (fs-TA) and electrochemical methods. (1)H-NMR shows that two doublets at 6.50 and 7.25(?) ppm belong to vinylic protons, which are characteristic of the formation of dyads. UV-Visible absorption spectra showed that dyads are merely superpositions of their respective constituent monomers and dominated by corrole S1 ? S0 (Q-band) and S2 ? S0 (Soret band) transitions with a systematic red-shift of both Soret and Q-bands along with the broadening of the bands. A prominent splitting of the Soret band for both the dyads is observed due to bulky substitutions at the peripheral position, which deviate from the planarity of the corrole macrocycle. Both the dyads exhibit significant fluorescence emission quenching (95-97%) of corrole emission compared to the free-base corrole monomer. Emission quenching is attributed to the excited-state intramolecular photoinduced electron transfer (PET) from corrole to anthraquinone in the dyad, whereas in the dyad it is reversed. The electron-transfer rates (kET) for and were found to be 3.33 × 10(11) and 2.78 × 10(10) s(-1), respectively. Despite their very different driving forces, charge separation (CS) and charge recombination (CR) are found to be in identical timescales. PMID:26247198

  3. Self-consistent absorption correction for quantitative energy- dispersive X-ray spectroscopy of InGaN layers in analytical transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Walther, T.; Wang, X.

    2015-10-01

    A new method of absorption correction for energy-dispersive X-ray spectroscopy in a transmission electron microscope is tested on InGaN samples. We simulate the effective k-factor for the In L line with respect to Ga L or Ga K and plot this as a function of the Ga K/L intensity ratio, which can be directly measured from experimental spectra. This basically performs an internal self-consistency check in the quantification using differently absorbed X-ray lines, which is in principle equivalent to an absorption correction as a function of specimen thickness but has the practical advantage that neither specimen thickness nor density or mass-thickness of the specimens need actually be measured.

  4. High-resolution ¹H magic angle spinning NMR spectroscopy of intact Arctic char (Salvelinus Alpinus) muscle. Quantitative analysis of n-3 fatty acids, EPA and DHA.

    PubMed

    Nestor, Gustav; Bankefors, Johan; Schlechtriem, Christian; Brännäs, Eva; Pickova, Jana; Sandström, Corine

    2010-10-27

    The lipid and small metabolite profiles from intact muscles of Arctic char were investigated using (1)H high-resolution magic angle spinning ((1)H HR-MAS) NMR spectroscopy. Not only the total n-3 fatty acid content but also the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) contents of the muscle were obtained from the (1)H HR-MAS NMR spectra without pretreatment of the tissue or lipophilic extraction. A number of small metabolites could also be observed, where creatine/phosphocreatine, anserine and taurine were the most abundant. Thus, the use of (1)H HR-MAS NMR led to simplified analysis techniques that can give direct information on the nutritional value of the fish. PMID:20873863

  5. Laser-induced breakdown spectroscopy technique for quantitative analysis of aqueous solution using matrix conversion based on plant fiber spunlaced nonwovens.

    PubMed

    Chen, Chenghan; Niu, Guanghui; Shi, Qi; Lin, Qingyu; Duan, Yixiang

    2015-10-01

    In the present work, laser-induced breakdown spectroscopy (LIBS) was applied to detect concentrations of chromium and nickel in aqueous solution in the form of matrix conversion using plant fiber spunlaced nonwovens as a solid-phase support, which can effectively avoid the inherent difficulties such as splashing, a quenching effect, and a shorter plasma lifetime during the liquid LIBS analysis. Drops of the sample solution were transferred to the plant fiber spunlaced nonwovens surface and uniformly diffused from the center to the whole area of the substrate. Owing to good hydrophilicity, the plant fiber spunlaced nonwovens can hold more of the liquid sample, and the surface of this material never wrinkles after being dried in a drying oven, which can effectively reduce the deviation during the LIBS analysis. In addition, the plant fiber spunlaced nonwovens used in the present work are relatively convenient and low cost. Also, the procedure of analysis was simple and fast, which are the unique features of LIBS technology. Therefore, this method has potential applications for practical and in situ analyses. To achieve sensitive elemental detection, the optimal delay time in this experiment was investigated. Under the optimized condition, the limits of detection for Cr and Ni are 0.7 and 5.7???g·mL-1, respectively. The results obtained in the present study show that the matrix conversion method is a feasible option for analyzing heavy metals in aqueous solutions by LIBS technology. PMID:26479603

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  7. Quantitative evaluation of molecular orientation in thin Langmuir-Blodgett films by FT-IR transmission and reflection-absorption spectroscopy

    SciTech Connect

    Umemura, Junzo; Kamata, Toshihide; Kawai, Takeshi; Takenaka, Tohru )

    1990-01-11

    By a comparison of infrared reflection-absorption (RA) and transmission intensities, a method for the quantitative evaluation of molecular orientation in thin Langmuir-Blodgett (LB) films has been developed. The enhancement factors for the RA to transmission absorption intensities of hypothetical isotropic films were theoretically calculated by using Hansen's optical formulas for thin multilayer films. By combination of these values with the experimentally determined intensity ratios of the RA to transmission spectra for uniaxially oriented LB films, the orientation angles of the transition moments of major infrared bands were evaluated. Application of this method to the 7-monolayer LB film of cadmium stearate deposited on AG (for RA measurements) and on ZnSe (for transmission measurements) substrates gave reasonable tilt angles for the molecular chain as compared to those reported by other investigators and to the data from the X-ray analysis. This method will be discussed in detail and the various factors which influence the accuracy of the orientation analysis will also be covered.

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

    NASA Astrophysics Data System (ADS)

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

    1988-06-01

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

  9. Quantitative analysis of the near-wall mixture formation process in a passenger car direct-injection Diesel engine by using linear Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Taschek, Marco; Egermann, Jan; Schwarz, Sabrina; Leipertz, Alfred

    2005-11-01

    Optimum fuel preparation and mixture formation are core issues in the development of modern direct-injection (DI) Diesel engines, as these are crucial for defining the border conditions for the subsequent combustion and pollutant formation process. The local fuel/air ratio can be seen as one of the key parameters for this optimization process, as it allows the characterization and comparison of the mixture formation quality. For what is the first time to the best of our knowledge, linear Raman spectroscopy is used to detect the fuel/air ratio and its change along a line of a few millimeters directly and nonintrusively inside the combustion bowl of a DI Diesel engine. By a careful optimization of the measurement setup, the weak Raman signals could be separated successfully from disturbing interferences. A simultaneous measurement of the densities of air and fuel was possible along a line of about 10 mm length, allowing a time- and space-resolved measurement of the local fuel/air ratio. This could be performed in a nonreacting atmosphere as well as during fired operating conditions. The positioning of the measurement volume next to the interaction point of one of the spray jets with the wall of the combustion bowl allowed a near-wall analysis of the mixture formation process for a six-hole nozzle under varying injection and engine conditions. The results clearly show the influence of the nozzle geometry and preinjection on the mixing process. In contrast, modulation of the intake air temperature merely led to minor changes of the fuel concentration in the measurement volume.

  10. In situ infrared emission spectroscopy for quantitative gas-phase measurement under high temperature reaction conditions: an analytical method for methane by means of an innovative small-volume flowing cell.

    PubMed

    Usseglio, Sandro; Thorshaug, Knut; Karlsson, Arne; Dahl, Ivar M; Nielsen, Claus J; Jens, Klaus-J; Tangstad, Elisabeth

    2010-02-01

    We have used infrared emission spectroscopy (IRES) in order to perform in situ studies under flowing gas-phase conditions. When the small-volume cell developed herein is used, we can (1) observe emission spectra from a hot gas-phase sample having an effective volume much less than one milliliter, (2) observe spectra of typical molecular species present, and (3) observe spectra of the more important molecular species down to below 10% and in some cases even as low as 1%. In addition, an analytical method has been derived in order to conduct quantitative studies under typical reaction conditions. We show that simplifications can be made in the data acquisition and handling for a direct linear correlation between band intensity and concentration with only simple background correction. The practical lower limit for methane in the present setup is approximately 0.5-1% v/v depending on the selected temperature. Our data were collected at 500, 600, and 700 degrees C, respectively. The major features of the present cell design are fairly simple and basically formed by a quartz tube (outer diameter=6 mm, inner diameter=4 mm) inside a metal pipe and two tubular ceramic heaters. This simple setup has advantages and attractive features that have extended the application of IRES to new fields and, in particular, for in situ studies of hydrocarbon reactions at different residence times at high temperature. PMID:20149274

  11. Influence of the colloidal structure of dairy gels on milk fat fusion behavior: quantification of the liquid fat content by in situ quantitative proton nuclear magnetic resonance spectroscopy (isq (1) H NMR).

    PubMed

    Bouteille, Romain; Perez, Jeanne; Khifer, Farid; Jouan-Rimbaud-Bouveresse, Delphine; Lecanu, Bruno; This, Hervé

    2013-04-01

    Dairy gels (DG), such as yoghurts, contain both solid and liquid fats at the time of consumption, as their temperature rises to anything between 10 and 24 °C after being introduced into the mouth at 4 °C. The mass ratio between solid and liquid fats, which depends on the temperature, impacts the organoleptic properties of DG. As the ordinary methods for determining this ratio can only be applied to samples consisting mainly in fat materials, a fat extraction step needs to be added into the analytical process when applied to DG, which prevents the study of the potential impact of their colloidal structure on milk fat fusion behavior. In situ quantitative proton nuclear magnetic resonance spectroscopy (isq (1) H NMR) was investigated as a method for direct measurements in DG: at temperatures between 20.0 and 70.0 °C, the liquid fat content and the composition of triacylglycerols of the liquid phase (in terms of alkyl chains length) were determined. Spectra of isolated milk fat also enable the quantification of the double bonds of triacylglycerols. Statistical tests showed no significant difference between isolated milk fat and milk fat inside a DG in terms of melting behavior: the fat globule membrane does not seem to have a significant influence on the fat melting behavior. PMID:23464867

  12. Relationship between the v2PO4/amide III ratio assessed by Raman spectroscopy and the calcium content measured by quantitative backscattered electron microscopy in healthy human osteonal bone

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  13. QUANTITATIVE SPECTROSCOPIC DETERMINATION OF HEMOGLOBIN CONCENTRATION AND

    E-print Network

    Fantini, Sergio

    QUANTITATIVE SPECTROSCOPIC DETERMINATION OF HEMOGLOBIN CONCENTRATION AND SATURATION IN A TURBID to the quantitative determination of hemoglobin concentration and saturation by near-infrared spectroscopy in turbid in the near-infrared, and the hemoglobin concentration was about 23 M. It was possible to reversibly saturate

  14. Characterisation of dissolved organic matter (DOM) in the Seine River catchment (France) by excitation-emission matrix (EEM) fluorescence spectroscopy combined with PARAFAC and PCA analyses

    NASA Astrophysics Data System (ADS)

    Thanh Nguyen, Phuong; Guo, Yuzhe; Bonnot, Caroline; Varrault, Gilles; Benedetti, Marc; Parlanti, Edith

    2014-05-01

    Dissolved organic matter (DOM) is a heterogeneous, complex mixture of compounds with wide ranging chemical properties and diverse origins. It is well known to interact with pollutants and to affect their transport and their fate in aquatic environment, and plays a vital role in the global cycling of carbon. In this study, UV/visible absorbance and excitation emission matrix (EEM) fluorescence spectroscopy combined with PARAFAC and PCA analyses have been used to characterize colloidal DOM in the Seine River watershed. Surface water samples were collected in November 2011, September 2012 (low-water) and February 2013 (flood) from 23, 39 and 45 sites respectively from different areas including the Oise basin, the Marne basin, the Grand Morin basin and the downstream of the Seine River. A Jasco V-560 spectrophotometer was used for UV/visible absorbance measurement. Fluorescence spectra were recorded using a Fluorolog FL3-22 SPEX - JOBIN YVON fluorometer. The samples, at natural pH, were placed in 1 cm quartz cuvette, thermostated at 20°C. All sample spectra were obtained by subtracting a blank spectrum (ultrapure water Milli-Q, Millipore) and were instrumentally corrected. When necessary, samples were diluted to avoid inner filter effects. The fluorescence data set was analyzed using PARAFAC DOMFluor toolbox in Matlab which decomposes the complex data matrix into its main components. The application of UV/visible absorbance and EEM fluorescence spectroscopy in combination with PARAFAC and PCA analyses allowed us to identify different sources of dissolved organic matter in the catchment of the Seine River and highlighted spatial and temporal variations of DOM properties. We observed significant different and specific typologies of organic matter for the four studied zones. The Seine basin is characterized by the strongest biological activity (in connection with the presence of the "Seine-Aval" WWTP). DOM from the Oise basin seems to have more "humic" characteristics (a forest sample presenting the strongest "humic-type" material). Samples collected from the Marne basin are characterized by a third specific type of organic matter. For samples collected in November 2011 and September 2012 the distributions observed for the 7 components determined by PARAFAC treatment were different for each studied basins, highlighting different organic materials in each zone. A homogeneous distribution of the components was obtained for the samples collected during the flood in February 2013.

  15. Journal of Quantitative Spectroscopy & Radiative Transfer ] (

    E-print Network

    , ammonium nitrate, sulfuric acid and nitric acid over a range of compositions and temperatures; Ammonium sulfate; Ammonium nitrate; Sulfuric acid; Nitric acid; Infrared remote sensing 1. Introduction

  16. Journal of Quantitative Spectroscopy & Radiative Transfer ] (

    E-print Network

    Gamache, Robert R.

    a Harvard-Smithsonian Center for Astrophysics, Atomic and Molecular Physics Division, Cambridge, MA 02138 enhancement in almost two decades. It now lists the Einstein A-coefficients, statistical weights of the upper

  17. Direct and quantitative absorptive spectroscopy of nanowires

    E-print Network

    Tong, Jonathan Kien-Kwok

    2012-01-01

    Photonic nanostructures exhibit unique optical properties that are attractive in many different applications. However, measuring the optical properties of individual nanostructures, in particular the absorptive properties, ...

  18. Quantitative spectroscopy for detection of cervical dysplasia

    E-print Network

    Mirkovi?, Jelena, Ph. D. Massachusetts Institute of Technology

    2009-01-01

    The current clinical standard for cervical cancer diagnosis is colposcopy, a procedure that involves visual inspection and biopsy of at-risk tissue, followed by histopathology. The major objective of colposcopy is detection ...

  19. * Corresponding author. Journal of Quantitative Spectroscopy &

    E-print Network

    Pardo-Carrión, Juan R.

    }433 Submillimeter atmospheric transmission measurements on Mauna Kea during extremely dry El Nin o conditions broadband atmospheric transmission spectra obtained on Mauna Kea, Hawaii (4100 m. above sea level) on UT humidity of +2%. As a result of its dryness the Mauna Kea site allows access to a partially transparent

  20. Ultraviolet Spectroscopy of Asteroid(4) Vesta

    NASA Technical Reports Server (NTRS)

    Li, Jian-Yang; Bodewits, Dennis; Feaga, Lori M.; Landsman, Wayne; A'Hearn, Michael F.; Mutchler, Max J.; Russell, Christopher T.; McFadden, Lucy A.; Raymond, Carol A.

    2011-01-01

    We report a comprehensive review of the UV-visible spectrum and rotational lightcurve of Vesta combining new observations by Hubble Space Telescope and Swift with archival International Ultraviolet Explorer observations. The geometric albedos of Vesta from 220 nm to 953 nm arc derived by carefully comparing these observations from various instruments at different times and observing geometries. Vesta has a rotationally averaged geometric albedo of 0.09 at 250 nm, 0.14 at 300 nm, 0.26 at 373 nm, 0.38 at 673 nm, and 0.30 at 950 nm. The linear spectral slope in the ultraviolet displays a sharp minimum ncar sub-Earth longitude of 20deg, and maximum in the eastern hemisphere. This is completely consistent with the distribution of the spectral slope in the visible wavelength. The uncertainty of the measurement in the ultraviolet is approx.20%, and in the visible wavelengths better than 10%. The amplitude of Vesta's rotational lightcurves is approx.10% throughout the range of wavelengths we observed, but is smaller at 950 nm (approx.6%) ncar the 1-micron mafic band center. Contrary to earlier reports, we found no evidence for any difference between the phasing of the ultraviolet and visible/ncar-infrared lightcurves with respect to sub-Earth longitude. Vesta's average spectrum between 220 and 950 nm can well be described by measured reflectance spectra of fine particle howardite-like materials of basaltic achondrite meteorites. Combining this with the in-phase behavior of the ultraviolet, visible. and ncar-infrared lightcurves, and the spectral slopes with respect to the rotational phase, we conclude that there is no global ultraviolet/visible reversal on Vesta. Consequently, this implies lack of global space weathering on Vesta. Keyword,: Asteroid Vesta; Spectrophotometry; Spectroscopy; Ultraviolet observations; Hubble Space Telescope observations

  1. On Quantitizing

    ERIC Educational Resources Information Center

    Sandelowski, Margarete; Voils, Corrine I.; Knafl, George

    2009-01-01

    "Quantitizing", commonly understood to refer to the numerical translation, transformation, or conversion of qualitative data, has become a staple of mixed methods research. Typically glossed are the foundational assumptions, judgments, and compromises involved in converting disparate data sets into each other and whether such conversions advance…

  2. Spectroscopy and chemistry of the atmosphere of Uranus

    NASA Technical Reports Server (NTRS)

    Fegley, Bruce, Jr.; Gautier, Daniel; Owen, Tobias; Prinn, Ronald G.

    1991-01-01

    A comprehensive review of the chemistry and spectroscopy of the Uranian atmosphere is presented by means of earth-based, earth-orbital, and Voyager 2 observations covering the UV, visible, infrared, and radio wavelength regions. It is inferred from these observations, in concert with the average density of about 1.3 g/cu cm, that the Uranian atmosphere is enriched in heavy elements relative to solar composition. Pre-Voyager earth-based observations of CH4 bands in the visible region and Voyager radio occultation data imply a CH4/H2 volume mixing ratio of about 2 percent corresponding to an enrichment of approximately 24 times the solar value of 0.000835. In contrast to CH4, microwave observations indicate an apparent depletion of NH3 in the 155-to-200-K region of the atmosphere by 100 to 200 times relative to the solar NH3/H2 mixing ratio of -0.000174. It is suggested that the temporal and latitudinal variations deduced for the NH3/H2 mixing ratio in this region of the Uranian atmosphere are due to atmospheric circulation effects.

  3. Development of a novel combined fluorescence and reflectance spectroscopy system for guiding high-grade glioma resections: confirmation of capability in lab experiments

    NASA Astrophysics Data System (ADS)

    Mousavi, Monirehalsadat; Xie, Haiyan; Xie, Zhiyuan; Brydegaard, Mikkel; Axelsson, Johan; Andersson-Engels, Stefan

    2013-11-01

    Total resection of glioblastoma multiform (GBM), the most common and aggressive malignant brain tumor, is challenging among other things due to difficulty in intraoperative discrimination between normal and residual tumor cells. This project demonstrates the potential of a system based on a combination of autofluorescence and diffuse reflectance spectroscopy to be useful as an intraoperative guiding tool. In this context, a system based on 5 LEDs coupled to optical fibers was employed to deliver UV/visible light to the sample sequentially. Remitted light from the tissue; including diffuse reflected and fluorescence of endogenous and exogenous fluorophores, as well as its photobleaching product, is transmitted to one photodiode and four avalanche photodiodes. This instrument has been evaluated with very promising results by performing various tissue-equivalent phantom laboratory and clinical studies on skin lesions.

  4. Quantitative radiography

    SciTech Connect

    Logan, C.M.; Hernandez, J.M.; Devine, G.J.

    1991-02-01

    We have developed a system of quantitative radiography in order to produce quantitative images displaying homogeneity of parts. The materials that we characterize are synthetic composites and may contain important subtle density variations not discernable by examining a raw film x-radiograph. In order to quantitatively interpret film radiographs, it is necessary to digitize, interpret, and display the images. Our integrated system of quantitative radiography displays accurate, high-resolution pseudocolor images in units of density. We characterize approximately 10,000 parts per year in hundreds of different configurations and compositions with this system. Images are captured using DuPont NDT55 industrial x-ray film in Daypack{trademark} packages. X-ray cabinets are of custom design, with helium flight path and a filter wheel for positioning filters if desired. The cabinets contain baffles to reduce scattered radiation and are equipped with drawer for rapid load/unload of parts. Separate units with tungsten-anode or copper-anode tubes are available. The usual operating voltage is 15 to 35 kVp. Fixturing provides for rough part positioning and precise alignment with respect to the x-ray source. Areal density standards are placed at several locations on each film. In interpreting the image, we use the standards nearest the image of the part being quantified. Because of this, small variations in x-ray flux uniformity (heel effects) are unimportant. The usual standard is a step wedge of aluminum containing 13 steps. Films are permanently labeled by imaging a perforated metal numbering strip. Data such as part number, step wedge identification, etc. are read from barcode labels and transferred to a data base for later retrieval and use in quantifying the image.

  5. Using one-dimensional (1D) and two-dimensional (2D) quantitative proton (1H) nuclear magnetic resonance spectroscopy (q NMR) for the identification and quantification of taste compounds in raw onion (Allium cepa L.) bulbs and in aqueous solutions where onion tissues are soaked.

    PubMed

    Tardieu, Audrey; De Man, Walter; This, Hervé

    2010-12-01

    Solutions obtained by soaking onion (Allium cepa L.) bulbs samples in water are frequently consumed, either directly or as part of dishes, both at home or in the food industry. However, little information is available regarding the extracted metabolites and the extraction mechanisms. In this article, the composition of raw onion extracts and of aqueous solutions where raw onion tissues were soaked was investigated directly by quantitative proton nuclear magnetic resonance spectroscopy (q (1)H NMR). The assignment of NMR signals was performed, with less than 3% (in area) of unidentified peaks. Analyses of one-dimensional (1)H NMR spectra with additional two-dimensional NMR studies showed 20 regions of interest where 3 saccharides, 17 amino acids, and 5 organic acids were detected and quantified. Resonance assignment with chemical shift was done for each saccharide, as well as for each amino acid and organic acid, with additional work on spin-spin coupling pattern and on observed and not observed correlations from correlation spectroscopy studies. Quantification of saccharides was performed and qualified by works on peak decomposition algorithms. Complementary studies by high-performance liquid chromatography, mass spectroscopy and tandem mass spectroscopy, and thin layer chromatography and preparative layer chromatography were carried out in order to validate the NMR results on identification. PMID:20972556

  6. Raman spectroscopy and microstructure of the pulsed laser-treated silver-anatase thick film

    NASA Astrophysics Data System (ADS)

    Joya, Yasir F.; Joya, K. S.; Bashir, S.; Anwar, A. W.; Rafique, M. S.; Ahmed, Riaz

    2015-09-01

    The present research describes the effect of laser pulses on crystalline titanium dioxide thick film with self-adsorbed silver ions. Anatase film of up to 4 µm thickness was deposited on ITO glass by doctor-blading technique. The film was heated at 450 °C for 60 min and cooled before immersion in silver nitrate aqueous solution. After drying, films were subjected to nanosecond pulses of the excimer laser, and their structural, microstructural and optical properties were investigated. Scanning electron microscopy and EDX analysis revealed the formation of silver nanoparticles (SNPs) dispersed in the anatase matrix. There was no significant change in the anatase structure as revealed by Raman spectroscopy. The intensity of Raman signals from pristine anatase film was increased after the laser treatment of silver ions on the film. This observation is associated with the phenomenon of localized surface plasmon resonance conferred by the crystalline SNPs. The results obtained by the UV-visible spectroscopy also support the role of SNPs to enhance the photoabsorption of the anatase film in the visible region.

  7. Analysis of organic pollutant degradation in pulsed plasma by coherent anti-Stokes Raman spectroscopy

    SciTech Connect

    Bratescu, Maria Antoneta; Hieda, Junko; Umemura, Tomonari; Saito, Nagahiro; Takai, Osamu

    2011-05-15

    The degradation of p-benzoquinone (p-BQ) in water was investigated by the coherent anti-Stokes Raman spectroscopy (CARS) method, in which the change of the anti-Stokes signal intensity corresponding to the vibrational transitions of the molecule is monitored during and after solution plasma processing (SPP). In the beginning of SPP treatment, the CARS signal intensity of the ring vibrational molecular transitions at 1233 and 1660 cm{sup -1} increases under the influence of the electric field of the plasma, depending on the delay time between the plasma pulse and the laser firing pulse. At the same time, the plasma contributes to the degradation of p-BQ molecules by generating hydrogen and hydroxyl radicals, which decompose p-BQ into different carboxylic acids. After SPP, the CARS signal intensity of the vibrational bands of p-BQ ceased and the degradation of p-BQ was confirmed by UV-visible absorption spectroscopy and liquid chromatography analysis.

  8. Multilayer approach to the quantitative analysis of x-ray photoelectron spectroscopy results: Applications to ultrathin SiO2 on Si and to self-assembled monolayers on gold

    NASA Astrophysics Data System (ADS)

    van der Marel, C.; Yildirim, M.; Stapert, H. R.

    2005-09-01

    X-ray photoelectron spectroscopy (XPS) is widely applied for the chemical characterization of surfaces and multilayers of thin films. In order to obtain quantitative results, XPS peak areas generally are divided by sensitivity factors and normalized to 100 at. % to obtain so-called raw concentrations. For homogeneous materials, materials with randomly distributed atoms within the analyzed surface layer, these concentrations may be a useful quantity. Yet, for a material consisting of a substrate on top of which a number of chemically different layers are present, the raw concentrations depend on measuring details like the takeoff angle during the XPS analyses and clearly are not a satisfactory way to describe the sample. The main purpose of this article is to present a calculation method that converts raw concentrations into more meaningful quantities. The method is applicable to a restricted but technologically relevant class of samples: substrates on top of which one or more homogeneous layers are present. Examples are: gate dielectrics on Si or GaAs, self-assembling monolayers on a metallic substrate, thin oxide films on metals with an organic contamination on top. The method is based upon standard exponential attenuation of the photoelectron intensity as a function of traveled distance. For each element or chemical state in the system it has to be known to which layer(s) it belongs. Sensitivity factors are corrected for matrix effects and for intrinsic excitations. Starting from the raw concentrations, the method calculates in a self-consistent way the composition of all layers in the system and the thickness of each layer. Only one measurement at one measuring angle is required to obtain these results. To obtain insight into the accuracy of the calculation method, XPS results obtained on ultrathin SiO2 layers on Si that were slightly contaminated with hydrocarbons have been analyzed with the method. The obtained thicknesses were in good agreement with values for the thickness of the SiO2 layer and the organic surface contamination as obtained by other methods. Consistent values were also obtained for the concentration ratio O/Si in the SiO2 layers. The calculation method has also been verified for three types of self-assembled monolayers (SAM layers) on gold. Layers of C18 (octadecane-thiol) and of EG4 (a mercaptoalkyloligo-ethyleneglycol) deposited from solutions with different concentrations were examined. Also, SAM layers deposited from mixtures with molecules with different chain lengths, mercapto-undecanol (MUO), and a biotinylated oligo-ethyleneglycol-alkyl thiol (BAT), were investigated. The model analysis provided the thickness of the organic layers, the concentrations of the components in the layers, and the coverage of the gold with sulphur (in atoms/cm2). Rutherford backscattering spectrometry (RBS) was applied to determine (in an independent way) the amount of sulphur at the gold surface. The RBS results correlated well with the XPS data. The obtained values for the concentration ratios of the SAM layers were in agreement with the theoretically expected values. It is shown in the article that it is essential to model the mixtures of MUO and BAT as a three-layer system (gold substrate, aliphatic interlayer, and top layer containing the ethylene oxide groups) in order to obtain agreement.

  9. High-pressure-low-temperature cryostat designed for use with fourier transform infrared spectrometers and time-resolved infrared spectroscopy.

    PubMed

    Calladine, James A; Love, Ashley; Fields, Peter A; Wilson, Richard G M; George, Michael W

    2014-01-01

    The design for a new high-pressure-low-temperature infrared (IR) cell for performing experiments using conventional Fourier transform infrared or fast laser-based time-resolved infrared spectroscopy, in a range of solvents, is described. The design builds upon a commercially available compressor and cold end (Polycold PCC(®) and CryoTiger(®)), which enables almost vibration-free operation, ideal for use with sensitive instrumentation. The design of our cell and cryostat allows for the study of systems at temperatures from 77 to 310 K and at pressures up to 250 bar. The CaF2 windows pass light from the mid-IR to the ultraviolet (UV), enabling a number of experiments to be performed, such as Raman, UV-visible absorption spectroscopy, and time-resolved techniques where sample excitation/probing using continuous wave or pulsed lasers is required. We demonstrate the capabilities of this cell by detailing two different applications: (i) the reactivity of a range of Group V-VII organometallic alkane complexes using time-resolved spectroscopy on the millisecond timescale and (ii) the gas-to-liquid phase transition of CO2 at low temperature, which is applicable to measurements associated with transportation issues related to carbon capture and storage. PMID:24666949

  10. Raman spectroscopy for noninvasive glucose measurements

    E-print Network

    Enejder, Annika M. K.

    We report the first successful study of the use of Raman spectroscopy for quantitative, noninvasive (“transcutaneous”) measurement of blood analytes, using glucose as an example. As an initial evaluation of the ability of ...

  11. Quarkonium spectroscopy

    SciTech Connect

    Scharre, D.L.

    1981-06-01

    Recent experimental investigations of heavy quark-antiquark bound state systems are reviewed. Results from SPEAR on charmonium spectroscopy and from DORIS and CESR on bottomonium spectroscopy are presented. The current status of the search for top is also discussed.

  12. Spectroscopies -- Theory

    NASA Astrophysics Data System (ADS)

    Törmä, Päivi

    2015-09-01

    This chapter explains how various spectroscopies can be used for probing the many-body quantum state of ultracold gas systems. It starts with a brief reminder of the basic theory of field-matter interactions. The general theory of linear response in the context of many-body quantum physics is then presented. A detailed theoretical description of RF spectroscopy, both the usual one and the momentum-resolved version, is given. This description applies to Raman spectroscopy as well. The basic theory behind Bragg spectroscopy and lattice modulation spectroscopy is also discussed. I explain how RF spectroscopy relates to the spectral function and how Bragg spectroscopy relates to the dynamical/static structure factor. The derivations are detailed and Green's functions are not used, so it is possible to follow this chapter based on simply knowing the basics of second quantization. Finally, self-consistent linear response theory and the use of sum rules is discussed in an overall manner.

  13. Role of trimer-trimer interaction of bacteriorhodopsin studied by optical spectroscopy and high-speed atomic force microscopy.

    PubMed

    Yamashita, Hayato; Inoue, Keiichi; Shibata, Mikihiro; Uchihashi, Takayuki; Sasaki, Jun; Kandori, Hideki; Ando, Toshio

    2013-10-01

    Bacteriorhodopsin (bR) trimers form a two-dimensional hexagonal lattice in the purple membrane of Halobacterium salinarum. However, the physiological significance of forming the lattice has long been elusive. Here, we study this issue by comparing properties of assembled and non-assembled bR trimers using directed mutagenesis, high-speed atomic force microscopy (HS-AFM), optical spectroscopy, and a proton pumping assay. First, we show that the bonds formed between W12 and F135 amino acid residues are responsible for trimer-trimer association that leads to lattice assembly; the lattice is completely disrupted in both W12I and F135I mutants. HS-AFM imaging reveals that both crystallized D96N and non-crystallized D96N/W12I mutants undergo a large conformational change (i.e., outward E-F loop displacement) upon light-activation. However, lattice disruption significantly reduces the rate of conformational change under continuous light illumination. Nevertheless, the quantum yield of M-state formation, measured by low-temperature UV-visible spectroscopy, and proton pumping efficiency are unaffected by lattice disruption. From these results, we conclude that trimer-trimer association plays essential roles in providing bound retinal with an appropriate environment to maintain its full photo-reactivity and in maintaining the natural photo-reaction pathway. PMID:23462099

  14. Time-resolved magnetic circular dichroism spectroscopy of photolyzed carbonmonoxy cytochrome c oxidase (cytochrome aa3).

    PubMed Central

    Goldbeck, R A; Dawes, T D; Einarsdóttir, O; Woodruff, W H; Kliger, D S

    1991-01-01

    Nanosecond time-resolved magnetic circular dichroism (TRMCD) and time-resolved natural circular dichroism (TRCD) measurements of photolysis products of the CO complex of eukaryotic cytochrome c oxidase (CcO-CO) are presented. TRMCD spectra obtained at 100 ns and 10 microseconds after photolysis are diagnostic of pentacoordinate cytochrome a3Fe2+, as would be expected for simple photodissociation. Other time-resolved spectroscopies (UV-visible and resonance Raman), however, show evidence for unusual Fea3(2+) coordination after CO photolysis (Woodruff, W. H., O. Einarsdóttir, R. B. Dyer, K. A. Bagley, G. Palmer, S. J. Atherton, R. A. Goldbeck, T. D. Dawes, and D. S. Kliger. 1991. Proc. Nat. Acad. Sci. U.S.A. 88:2588-2592). Furthermore, time-resolved IR experiments have shown that photodissociated CO binds to CuB+ prior to recombining with Fea3(2+) (Dyer, R. B., O. Einarsdóttir, P. M. Killough, J. J. López-Garriga, and W. H. Woodruff. 1989. J. Am. Chem. Soc. 111:7657-7659). A model of the CcO-CO photolysis cycle which is consistent with all of the spectroscopic results is presented. A novel feature of this model is the coordination of a ligand endogenous to the protein to the Fe axial site vacated by the photolyzed CO and the simultaneous breaking of the Fe-imidazole(histidine) bond. PMID:1653049

  15. The Future of UV-Visible Astronomy from Space - the NASA COPAG SIG

    NASA Astrophysics Data System (ADS)

    Scowen, Paul

    2015-08-01

    The ultraviolet (92-320nm) and visible (320-1000nm) (UVV) regions of the spectrum contain a vital suite of diagnostic lines that can be used to study diverse astronomical objects and phenomena that shape and energize the interstellar medium. It is a critical spectral range for tracing the physics of interstellar and intergalactic gas, the ionization of nebulae, the properties of shocks, the atmospheres and winds of hot stars, energy transfer between galaxies and their surrounding environments, and the engines of active galactic nuclei. This spectral range contains diagnostics that measure gas density, electron temperature, and energy balance between various modes of cooling. It is an unfortunate truth that many, if not most, of these diagnostics can only be observed outside the Earth’s atmosphere, requiring facilities in space. Space-based observations also provide access to diffraction-limited optical performance to achieve high spatial resolution. Such spatial resolutions cannot currently be achieved from the ground over wide fields, a capability that many science programs need for sampling and survey work.In order to provide continuing access in the future, new space-based missions will be needed to provide the core imaging and spectroscopic information in this important part of the electromagnetic spectrum. The technology that enables such access has been a high priority in technology development plans that have been developed by both the Cosmic Origins Program Office and Astrophysics Division at NASA, but a holistic approach to considering what is needed for a long-term technology roadmap has not yet been discussed widely within the community. This UVV Science Interest Group [SIG #2] has been established to collect community input and define long-term Cosmic Origins science objectives of the UVV astronomy community that can be addressed by space-based observations. The SIG facilitates communication to merge the needs and desires of the science community with the achievements and plans of the technology community. The SIG is open to any interested members of the community and we welcome any and all input. SIG website: http://sig2.asu.edu.

  16. Improved Algorithms for Accurate Retrieval of UV - Visible Diffuse Attenuation Coefficients in Optically Complex, Inshore Waters

    NASA Technical Reports Server (NTRS)

    Cao, Fang; Fichot, Cedric G.; Hooker, Stanford B.; Miller, William L.

    2014-01-01

    Photochemical processes driven by high-energy ultraviolet radiation (UVR) in inshore, estuarine, and coastal waters play an important role in global bio geochemical cycles and biological systems. A key to modeling photochemical processes in these optically complex waters is an accurate description of the vertical distribution of UVR in the water column which can be obtained using the diffuse attenuation coefficients of down welling irradiance (Kd()). The Sea UV Sea UVc algorithms (Fichot et al., 2008) can accurately retrieve Kd ( 320, 340, 380,412, 443 and 490 nm) in oceanic and coastal waters using multispectral remote sensing reflectances (Rrs(), Sea WiFS bands). However, SeaUVSeaUVc algorithms are currently not optimized for use in optically complex, inshore waters, where they tend to severely underestimate Kd(). Here, a new training data set of optical properties collected in optically complex, inshore waters was used to re-parameterize the published SeaUVSeaUVc algorithms, resulting in improved Kd() retrievals for turbid, estuarine waters. Although the updated SeaUVSeaUVc algorithms perform best in optically complex waters, the published SeaUVSeaUVc models still perform well in most coastal and oceanic waters. Therefore, we propose a composite set of SeaUVSeaUVc algorithms, optimized for Kd() retrieval in almost all marine systems, ranging from oceanic to inshore waters. The composite algorithm set can retrieve Kd from ocean color with good accuracy across this wide range of water types (e.g., within 13 mean relative error for Kd(340)). A validation step using three independent, in situ data sets indicates that the composite SeaUVSeaUVc can generate accurate Kd values from 320 490 nm using satellite imagery on a global scale. Taking advantage of the inherent benefits of our statistical methods, we pooled the validation data with the training set, obtaining an optimized composite model for estimating Kd() in UV wavelengths for almost all marine waters. This optimized composite set of SeaUVSeaUVc algorithms will provide the optical community with improved ability to quantify the role of solar UV radiation in photochemical and photobiological processes in the ocean.

  17. HVI color and UV/visible spectral response of cotton fibers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Classification of cotton color is assessed by both human classers and HVI measurements. However, there are demonstrated inconsistencies between them, partly due to the human classer’s subjective perception and partly due to HVI’s 2-filter limitation. To improve the agreement, a number of attempts ha...

  18. Thermal decomposition and flammability of fire-resistant, UV/visible-sensitive polyarylates, copolymers and blends

    E-print Network

    Research, University of Massachusetts, Amherst, MA 01003, USA b Department of Chemical Engineering Thermal decomposition behavior and flammability of three polyarylates based on bisphenol A (BPA), 1- resistant polymers has attracted considerable research activity during the last 30 years [1­5]. Polyarylates

  19. An Improved Flame Test for Qualitative Analysis Using a Multichannel UV-Visible Spectrophotometer

    ERIC Educational Resources Information Center

    Blitz, Jonathan P.; Sheeran, Daniel J.; Becker, Thomas L.

    2006-01-01

    Qualitative analysis schemes are used in undergraduate laboratory settings as a way to introduce equilibrium concepts and logical thinking. The main component of all qualitative analysis schemes is a flame test, as the color of light emitted from certain elements is distinctive and a flame photometer or spectrophotometer in each laboratory is…

  20. The Hubble Space Telescope: UV, Visible, and Near-Infrared Pursuits

    NASA Technical Reports Server (NTRS)

    Wiseman, Jennifer

    2010-01-01

    The Hubble Space Telescope continues to push the limits on world-class astrophysics. Cameras including the Advanced Camera for Surveys and the new panchromatic Wide Field Camera 3 which was installed nu last year's successful servicing mission S2N4,o{fer imaging from near-infrared through ultraviolet wavelengths. Spectroscopic studies of sources from black holes to exoplanet atmospheres are making great advances through the versatile use of STIS, the Space Telescope Imaging Spectrograph. The new Cosmic Origins Spectrograph, also installed last year, is the most sensitive UV spectrograph to fly io space and is uniquely suited to address particular scientific questions on galaxy halos, the intergalactic medium, and the cosmic web. With these outstanding capabilities on HST come complex needs for laboratory astrophysics support including atomic and line identification data. I will provide an overview of Hubble's current capabilities and the scientific programs and goals that particularly benefit from the studies of laboratory astrophysics.

  1. PSC and volcanic aerosol observations during EASOE by UV-visible ground-based spectrometry

    SciTech Connect

    Sarkissian, A.; Pommereau, J.P.; Goutail, F. ); Kyro, E. )

    1994-06-22

    This paper presents results from ground-based spectrometry of twilight sky color in the UV and visible region, taken at four stations on the arctic circle. These stations observed the appearance of aerosol layers from the volcanic eruption of Mt. Pinatubo in mid 1991. The aerosol density increased steadily at lower stratospheric levels, and spread inside the polar vortex. These stations only observed one high altitude PSC during this winter campaign.

  2. UV, VISIBLE AND NIR SPECTRAL ANALYSIS OF EGGSHELLS IN THE CHARADRIIDAE FAMILY OF BIRDS

    EPA Science Inventory

    We employed reflectance spectrophotometry to quantify color and mineral composition of eggshells from several species of the bird family Charadriidae to characterize species physiology and to distinguish nesting habitat preferences. We used a Shimadzu spectrophotometer to measur...

  3. Teledyne Imaging Sensors: Silicon CMOS imaging technologies for x-ray, UV, visible, and near infrared

    NASA Astrophysics Data System (ADS)

    Bai, Yibin; Bajaj, Jagmohan; Beletic, James W.; Farris, Mark C.; Joshi, Atul; Lauxtermann, Stefan; Petersen, Anders; Williams, George

    2008-07-01

    Teledyne Imaging Sensors develops and produces high performance silicon-based CMOS image sensors, with associated electronics and packaging for astronomy and civil space. Teledyne's silicon detector sensors use two technologies: monolithic CMOS, and silicon PIN hybrid CMOS. Teledyne's monolithic CMOS sensors are large (up to 59 million pixels), low noise (2.8 e- readout noise demonstrated, 1-2 e- noise in development), low dark current (<10 pA/cm2 at 295K) and can provide in-pixel snapshot shuttering with >103 extinction and microsecond time resolution. The QE limitation of frontside-illuminated CMOS is being addressed with specialized microlenses and backside illumination. A monolithic CMOS imager is under development for laser guide star wavefront sensing. Teledyne's hybrid silicon PIN CMOS sensors, called HyViSITM, provide high QE for the x-ray through near IR spectral range and large arrays (2K×2K, 4K×4K) are being produced with >99.9% operability. HyViSI dark current is 5-10 nA/cm2 (298K), and further reduction is expected from ongoing development. HyViSI presently achieves <10 e- readout noise, and new high speed HyViSI arrays being produced in 2008 should achieve <4 e- readout noise at 900 Hz frame rate. A Teledyne 640×480 pixel HyViSI array is operating in the Mars Reconnaissance Orbiter, a 1K×1K HyViSI array will be launched in 2008 in the Orbiting Carbon Observatory, and HyViSI arrays are under test at several astronomical observatories. The advantages of CMOS in comparison to CCD include programmable readout modes, faster readout, lower power, radiation hardness, and the ability to put specialized processing within each pixel. We present one example of in-pixel processing: event driven readout that is optimal for lightning detection and x-ray imaging.

  4. Characterization of tannin-metal complexes by UV-visible spectrophotometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tannins enter soils by plant decay and rain throughfall, but little is known of their effects on soils. Tannins may influence bioavailability and toxicity of metals by forming complexes and by mediating redox reactions. We evaluated the affinity and stoichiometry of Al(III) for a gallotannin, pent...

  5. Quantitative Electron Nanodiffraction.

    SciTech Connect

    Spence, John

    2015-01-30

    This Final report summarizes progress under this award for the final reporting period 2002 - 2013 in our development of quantitive electron nanodiffraction to materials problems, especially devoted to atomistic processes in semiconductors and electronic oxides such as the new artificial oxide multilayers, where our microdiffraction is complemented with energy-loss spectroscopy (ELNES) and aberration-corrected STEM imaging (9). The method has also been used to map out the chemical bonds in the important GaN semiconductor (1) used for solid state lighting, and to understand the effects of stacking sequence variations and interfaces in digital oxide superlattices (8). Other projects include the development of a laser-beam Zernike phase plate for cryo-electron microscopy (5) (based on the Kapitza-Dirac effect), work on reconstruction of molecular images using the scattering from many identical molecules lying in random orientations (4), a review article on space-group determination for the International Tables on Crystallography (10), the observation of energy-loss spectra with millivolt energy resolution and sub-nanometer spatial resolution from individual point defects in an alkali halide, a review article for the Centenary of X-ray Diffration (17) and the development of a new method of electron-beam lithography (12). We briefly summarize here the work on GaN, on oxide superlattice ELNES, and on lithography by STEM.

  6. The contribution of Raman spectroscopy to the analytical quality control of cytotoxic drugs in a hospital environment: eliminating the exposure risks for staff members and their work environment.

    PubMed

    Bourget, Philippe; Amin, Alexandre; Vidal, Fabrice; Merlette, Christophe; Troude, Pénélope; Baillet-Guffroy, Arlette

    2014-08-15

    The purpose of the study was to perform a comparative analysis of the technical performance, respective costs and environmental effect of two invasive analytical methods (HPLC and UV/visible-FTIR) as compared to a new non-invasive analytical technique (Raman spectroscopy). Three pharmacotherapeutic models were used to compare the analytical performances of the three analytical techniques. Statistical inter-method correlation analysis was performed using non-parametric correlation rank tests. The study's economic component combined calculations relative to the depreciation of the equipment and the estimated cost of an AQC unit of work. In any case, analytical validation parameters of the three techniques were satisfactory, and strong correlations between the two spectroscopic techniques vs. HPLC were found. In addition, Raman spectroscopy was found to be superior as compared to the other techniques for numerous key criteria including a complete safety for operators and their occupational environment, a non-invasive procedure, no need for consumables, and a low operating cost. Finally, Raman spectroscopy appears superior for technical, economic and environmental objectives, as compared with the other invasive analytical methods. PMID:24792972

  7. XPS, UV-vis spectroscopy and AFM studies on removal mechanisms of Si-face SiC wafer chemical mechanical polishing (CMP)

    NASA Astrophysics Data System (ADS)

    Zhou, Yan; Pan, Guoshun; Shi, Xiaolei; Xu, Li; Zou, Chunli; Gong, Hua; Luo, Guihai

    2014-10-01

    Chemical mechanical polishing (CMP) removal mechanisms of on-axis Si-face SiC wafer have been investigated through X-ray photoelectron spectroscopy (XPS), UV-visible (UV-vis) spectroscopy and atomic force microscopy (AFM). XPS results indicate that silicon oxide is formed on Si-face surface polished by the slurry including oxidant H2O2, but not that after immersing in H2O2 solution. UV-vis spectroscopy curves prove that •OH hydroxyl radical could be generated only under CMP polishing by the slurry including H2O2 and abrasive, so as to promote oxidation of Si-face to realize the effective removal; meanwhile, alkali KOH during CMP could induce the production of more radicals to improve the removal. On the other side, ultra-smooth polished surface with atomic step structure morphology and extremely low Ra of about 0.06 nm (through AFM) is obtained using the developed slurry with silica nanoparticle abrasive. Through investigating the variations of the atomic step morphology on the surface polished by different slurries, it's reveals that CMP removal mechanism involves a simultaneous process of surface chemical reaction and nanoparticle atomic scale abrasion.

  8. Synthesis, crystal structure, vibrational spectroscopy, optical properties and theoretical studies of a new organic-inorganic hybrid material: [((CH3)2NH2)+]6·[(BiBr6)3-]2

    NASA Astrophysics Data System (ADS)

    Ben Ahmed, A.; Feki, H.; Abid, Y.

    2014-12-01

    A new organic-inorganic hybrid material, [((CH3)2NH2)+]6·[(BiBr6)3-]2, has been synthesized and characterized by X-ray diffraction, FT-IR, Raman spectroscopy and UV-Visible absorption. The studied compound crystallizes in the triclinic system, space group P1bar with the following parameters: a=8.4749(6)(Å), b=17.1392(12)(Å), c=17.1392(12)(Å), ? = 117.339(0)°, ? = 99.487(0)°, ? = 99.487(0)° and Z = 2. The crystal lattice is composed of a two discrete (BiBr6)3- anions surrounded by six ((CH3)2NH2)+ cations. Complex hydrogen bonding interactions between (BiBr6)3- and organic cations from a three-dimensional network. Theoretical calculations were performed using density functional theory (DFT) for studying the molecular structure, vibrational spectra and optical properties of the investigated molecule in the ground state. The full geometry optimization of designed system is performed using DFT method at B3LYP/LanL2DZ level of theory using the Gaussian03. The optimized geometrical parameters obtained by DFT calculations are in good agreement with single crystal XRD data. The vibrational spectral data obtained from FT-IR and Raman spectra are assigned based on the results of the theoretical calculations. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) results complements with the experimental findings. The simulated spectra satisfactorily coincide with the experimental UV-Visible spectrum. The results show good consistent with the experiment and confirm the contribution of metal orbital to the HOMO-LUMO boundary.

  9. Quantitation of carcinogen bound protein adducts by fluorescence measurements

    NASA Astrophysics Data System (ADS)

    Gan, Liang-Shang; Otteson, Michael S.; Doxtader, Mark M.; Skipper, Paul L.; Dasari, Ramachandra R.; Tannenbaum, Steven R.

    1989-01-01

    A highly significant correlation of aflatoxin B 1 serum albumin adduct level with daily aflatoxin B 1 intake was observed in a molecular epidemiological study of aflatoxin carcinogenesis which used conventional fluorescence spectroscopy methods for adduct quantitation. Synchronous fluorescence spectroscopy and laser induced fluorescence techniques have been employed to quantitate antibenzo[ a]pyrene diol epoxide derived globin peptide adducts. Fast and efficient methods to isolate the peptide adducts as well as eliminate protein fluorescence background are described. A detection limit of several femtomoles has been achieved. Experimental and technical considerations of low temperature synchronous fluorescence spectroscopy and fluorescence line narrowing to improve the detection sensitivities are also presented.

  10. Raman Spectroscopy.

    ERIC Educational Resources Information Center

    Gerrard, Donald L.

    1984-01-01

    Reviews literature on Raman spectroscopy from late 1981 to late 1983. Topic areas include: instrumentation and sampling; liquids and solutions; gases and matrix isolation; biological molecules; polymers; high-temperature and high-pressure studies; Raman microscopy; thin films and surfaces; resonance-enhanced and surface-enhanced spectroscopy; and…

  11. The trouble with spectroscopy papers.

    PubMed

    Bottomley, P A

    1991-11-01

    Writing a critique and guide for authors of clinical spectroscopy research papers is a likely way of ensuring that one never sees another of one's own papers published in this field. Nevertheless, it is disappointing, though perhaps predictable, that despite its historical foundations in quantitative spectroscopy, the field has its fair share of findings that are not so obviously reconciled. Here is the view of one author, one referee, and one spectroscopy protagonist about what might be expected of a clinical spectroscopy paper. In addition to novelty, the fundamental criteria for acceptance should be that the conclusions are supported by properly and objectively quantified results, and that sufficient experimental detail is provided so that one skilled in the art could reproduce the study and its findings. PMID:1924769

  12. The trouble with spectroscopy papers.

    PubMed

    Bottomley, P A

    1992-01-01

    Writing a critique and guide for authors of clinical spectroscopy research papers is a likely way of ensuring that one never sees another of one's own papers published in this field. Nevertheless, it is disappointing, though perhaps predictable, that despite its historical foundations in quantitative spectroscopy, the field has its fair share of findings that are not so obviously reconciled. Here is the view of one author, one referee, and one spectroscopy protagonist about what might be expected of a clinical spectroscopy paper. In addition to novelty, the fundamental criteria for acceptance should be that the conclusions are supported by properly and objectively quantified results, and that sufficient experimental detail is provided so that one skilled in the art could reproduce the study and its findings. PMID:1623275

  13. Quantitative Mineralogical Characterization of Oregon Erionite

    NASA Astrophysics Data System (ADS)

    Dogan, A.; Dogan, M.; Ballirano, P.

    2006-12-01

    Erionite has been classified as Group-I Human Carcinogen by the IARC Working Group. Fibrogenetic potential of erionite varies from low to high yield of mesothelioma. This may require quantitative characterization of physicochemical properties of erionite before any experimental design. The toxicity of the mineral is such that quantitative characterization of erionite is extremely important. Yet, often the erionite specimens were incompletely or incorrectly characterized throwing doubt on the results of the work. For example, none of the Turkish erionite published until recently had balance error (E%) less than 10%, and Mg cation of the type specimen of erionite-Ca from Maze, Niigita Prefecture, Japan is more than 0.8. In the present study, erionite sample near Rome, Oregon have been quantitatively characterized using powder x-ray diffraction, Reitveld refinement, scanning electron microscopy, energy dispersive spectroscopy, inductively coupled plasma - mass spectroscopy, and Massbauer spectroscopy. The cell parameters of the erionite-K from Oregon is computed as a=13.2217(2) Å and c=15.0671 Å; chemical composition of the erionite as major oxides, rare earth elements and other trace elements, are characterized quantitatively. Crystal chemistries of the erionite are computed based upon the quidelines of the IMAA zeolite report of 1997.

  14. Anatomy-Based Algorithms for Detecting Oral Cancer Using Reflectance and Fluorescence Spectroscopy

    E-print Network

    McGee, Sasha

    OBJECTIVES: We used reflectance and fluorescence spectroscopy to noninvasively and quantitatively distinguish benign from dysplastic/malignant oral lesions. We designed diagnostic algorithms to account for differences in ...

  15. Preparation of gold nanoparticles by microwave heating and application of spectroscopy to study conjugate of gold nanoparticles with antibody E. coli O157:H7

    NASA Astrophysics Data System (ADS)

    Thanh Ngo, Vo Ke; Phuong Uyen Nguyen, Hoang; Phat Huynh, Trong; Nguyen Pham Tran, Nguyen; Lam, Quang Vinh; Dat Huynh, Thanh

    2015-09-01

    Gold nanoparticles (AuNPs) of 15-20 nm size range have attracted attention for producing smart sensing devices as diagnostic tools in biomedical sciences. Citrate capped AuNPs are negatively charged, which can be exploited for electrostatic interactions with some positively charged biomolecules like antibodies. In this paper we describe a method for the low cost synthesis of gold nanoparticles using sodium citrate (Na3Ct) reduction in chloroauric acid (HAuCl4.3H2O) by microwave heating (diameter about 13-15 nm). Gold nanoparticles were functionalized with surface activation by 3-mercaptopropionic acid for attaching antibody. These nanoparticles were then reacted with anti-E. coli O157:H7, using N-hydroxy succinimide (NHS) and carbondimide hydrochloride (EDC) coupling chemistry. The product was characterized with UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy and zeta potential. In addition, the binding of antibody-gold nanoparticles conjugates to E. coli O157:H7 was demonstrated using transmission electron microscopy (TEM).

  16. Identification of different species of Bacillus isolated from Nisargruna Biogas Plant by FTIR, UV-Vis and NIR spectroscopy.

    PubMed

    Ghosh, S B; Bhattacharya, K; Nayak, S; Mukherjee, P; Salaskar, D; Kale, S P

    2015-09-01

    Definitive identification of microorganisms, including pathogenic and non-pathogenic bacteria, is extremely important for a wide variety of applications including food safety, environmental studies, bio-terrorism threats, microbial forensics, criminal investigations and above all disease diagnosis. Although extremely powerful techniques such as those based on PCR and microarrays exist, they require sophisticated laboratory facilities along with elaborate sample preparation by trained researchers. Among different spectroscopic techniques, FTIR was used in the 1980s and 90s for bacterial identification. In the present study five species of Bacillus were isolated from the aerobic predigester chamber of Nisargruna Biogas Plant (NBP) and were identified to the species level by biochemical and molecular biological (16S ribosomal DNA sequence) methods. Those organisms were further checked by solid state spectroscopic absorbance measurements using a wide range of electromagnetic radiation (wavelength 200 nm to 25,000 nm) encompassing UV, visible, near Infrared and Infrared regions. UV-Vis and NIR spectroscopy was performed on dried bacterial cell suspension on silicon wafer in specular mode while FTIR was performed on KBr pellets containing the bacterial cells. Consistent and reproducible species specific spectra were obtained and sensitivity up to a level of 1000 cells was observed in FTIR with a DTGS detector. This clearly shows the potential of solid state spectroscopic techniques for simple, easy to implement, reliable and sensitive detection of bacteria from environmental samples. PMID:25930088

  17. Synthesis, spectroscopy, X-ray crystallography, DFT calculations, DNA binding and molecular docking of a propargyl arms containing Schiff base.

    PubMed

    Balakrishnan, C; Subha, L; Neelakantan, M A; Mariappan, S S

    2015-11-01

    A propargyl arms containing Schiff base (L) was synthesized by the condensation of 1-[2-hydroxy-4-(prop-2-yn-1-yloxy)phenyl]ethanone with trans-1,2-diaminocyclohexane. The structure of L was characterized by IR, (1)H NMR, (13)C NMR and UV-Vis spectroscopy and by single crystal X-ray diffraction analysis. The UV-Visible spectral behavior of L in different solvents exhibits positive solvatochromism. Density functional calculation of the L in gas phase was performed by using DFT (B3LYP) method with 6-31G basis set. The computed vibrational frequencies and NMR signals of L were compared with the experimental data. Tautomeric stability study inferred that the enolimine is more stable than the ketoamine form. The charge delocalization has been analyzed using natural bond orbital (NBO) analysis. Electronic absorption and emission spectral studies were used to study the binding of L with CT-DNA. The molecular docking was done to identify the interaction of L with A-DNA and B-DNA. PMID:26093117

  18. Identification of different species of Bacillus isolated from Nisargruna Biogas Plant by FTIR, UV-Vis and NIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Ghosh, S. B.; Bhattacharya, K.; Nayak, S.; Mukherjee, P.; Salaskar, D.; Kale, S. P.

    2015-09-01

    Definitive identification of microorganisms, including pathogenic and non-pathogenic bacteria, is extremely important for a wide variety of applications including food safety, environmental studies, bio-terrorism threats, microbial forensics, criminal investigations and above all disease diagnosis. Although extremely powerful techniques such as those based on PCR and microarrays exist, they require sophisticated laboratory facilities along with elaborate sample preparation by trained researchers. Among different spectroscopic techniques, FTIR was used in the 1980s and 90s for bacterial identification. In the present study five species of Bacillus were isolated from the aerobic predigester chamber of Nisargruna Biogas Plant (NBP) and were identified to the species level by biochemical and molecular biological (16S ribosomal DNA sequence) methods. Those organisms were further checked by solid state spectroscopic absorbance measurements using a wide range of electromagnetic radiation (wavelength 200 nm to 25,000 nm) encompassing UV, visible, near Infrared and Infrared regions. UV-Vis and NIR spectroscopy was performed on dried bacterial cell suspension on silicon wafer in specular mode while FTIR was performed on KBr pellets containing the bacterial cells. Consistent and reproducible species specific spectra were obtained and sensitivity up to a level of 1000 cells was observed in FTIR with a DTGS detector. This clearly shows the potential of solid state spectroscopic techniques for simple, easy to implement, reliable and sensitive detection of bacteria from environmental samples.

  19. Cultural heritage and archaeology materials studied by synchrotron spectroscopy and imaging

    NASA Astrophysics Data System (ADS)

    Bertrand, Loïc; Robinet, Laurianne; Thoury, Mathieu; Janssens, Koen; Cohen, Serge X.; Schöder, Sebastian

    2012-02-01

    The use of synchrotron radiation techniques to study cultural heritage and archaeological materials has undergone a steep increase over the past 10-15 years. The range of materials studied is very broad and encompasses painting materials, stone, glass, ceramics, metals, cellulosic and wooden materials, and a cluster of organic-based materials, in phase with the diversity observed at archaeological sites, museums, historical buildings, etc. Main areas of investigation are: (1) the study of the alteration and corrosion processes, for which the unique non-destructive speciation capabilities of X-ray absorption have proved very beneficial, (2) the understanding of the technologies and identification of the raw materials used to produce archaeological artefacts and art objects and, to a lesser extent, (3) the investigation of current or novel stabilisation, conservation and restoration practices. In terms of the synchrotron methods used, the main focus so far has been on X-ray techniques, primarily X-ray fluorescence, absorption and diffraction, and Fourier-transform infrared spectroscopy. We review here the use of these techniques from recent works published in the field demonstrating the breadth of applications and future potential offered by third generation synchrotron techniques. New developments in imaging and advanced spectroscopy, included in the UV/visible and IR ranges, could even broaden the variety of materials studied, in particular by fostering more studies on organic and complex organic-inorganic mixtures, while new support activities at synchrotron facilities might facilitate transfer of knowledge between synchrotron specialists and users from archaeology and cultural heritage sciences.

  20. 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.

    PubMed

    Bellur Atici, Esen; Karl??a, 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 ? and ? forms. Molecules in ? and ? 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 ? and ? polymorphs were characterized and used throughout the method development and validation studies. Mixtures with different ratios of ? and ? forms were scanned using X-ray diffractometer with a scan rate of 0.250°/min over an angular range of 19.5-21.0° 2? and the peak heights for characteristic peak of ? form at 20.5 ± 0.2° 2? diffraction angle were used to generate a calibration curve. The detection limit of ? polymorph in ? form imatinib mesylate tablets was found as 4% and the linear regression analysis data for the calibration plots showed good linear relationship with correlation coefficient of 0.992 with respect to relative peak height in the concentration range of 12-75 wt% ? form containing tablet mixtures. The obtained results at each stage of the validation study proved that the method is specific, repeatable, precise and accurate, and could be used for determination of ? polymorph content in tablets produced by using ? polymorph of imatinib mesylate. The developed PXRD quantification method was used to monitor the polymorphic purity of ? form drug substance and corresponding drug products during the quality control analyses and stability studies, and the results indicated that ? form was stable and not converted to ? form during the manufacturing process and stability period. PMID:26099262

  1. Early diagnosis of cancer using light scattering spectroscopy

    E-print Network

    Backman, Vadim, 1973-

    2001-01-01

    This thesis presents a novel optical technique, light scattering spectroscopy (LSS), developed for quantitative characterization of tissue morphology as well as in vivo detection and diagnosis of the diseases associated ...

  2. Modern Spectroscopy

    ERIC Educational Resources Information Center

    Barrow, Gordon M.

    1970-01-01

    Presents the basic ideas of modern spectroscopy. Both the angular momenta and wave-nature approaches to the determination of energy level patterns for atomic and molecular systems are discussed. The interpretation of spectra, based on atomic and molecular models, is considered. (LC)

  3. Quantitative Measurements of HO2 and other products of n-butane oxidation (H2O2, H2O, CH2O, and C2H4) at elevated temperatures by direct coupling of a jet-stirred reactor with sampling nozzle and cavity ring-down spectroscopy (cw-CRDS).

    PubMed

    Djehiche, Mokhtar; Le Tan, Ngoc Linh; Jain, Chaithanya D; Dayma, Guillaume; Dagaut, Philippe; Chauveau, Christian; Pillier, Laure; Tomas, Alexandre

    2014-11-26

    For the first time quantitative measurements of the hydroperoxyl radical (HO2) in a jet-stirred reactor were performed thanks to a new experimental setup involving fast sampling and near-infrared cavity ring-down spectroscopy at low pressure. The experiments were performed at atmospheric pressure and over a range of temperatures (550-900 K) with n-butane, the simplest hydrocarbon fuel exhibiting cool flame oxidation chemistry which represents a key process for the auto-ignition in internal combustion engines. The same technique was also used to measure H2O2, H2O, CH2O, and C2H4 under the same conditions. This new setup brings new scientific horizons for characterizing complex reactive systems at elevated temperatures. Measuring HO2 formation from hydrocarbon oxidation is extremely important in determining the propensity of a fuel to follow chain-termination pathways from R + O2 compared to chain branching (leading to OH), helping to constrain and better validate detailed chemical kinetics models. PMID:25381864

  4. Grain Spectroscopy

    NASA Technical Reports Server (NTRS)

    Allamandola, L. J.

    1992-01-01

    Our fundamental knowledge of interstellar grain composition has grown substantially during the past two decades thanks to significant advances in two areas: astronomical infrared spectroscopy and laboratory astrophysics. The opening of the mid-infrared, the spectral range from 4000-400 cm(sup -1) (2.5-25 microns), to spectroscopic study has been critical to this progress because spectroscopy in this region reveals more about a materials molecular composition and structure than any other physical property. Infrared spectra which are diagnostic of interstellar grain composition fall into two categories: absorption spectra of the dense and diffuse interstellar media, and emission spectra from UV-Vis rich dusty regions. The former will be presented in some detail, with the latter only very briefly mentioned. This paper summarized what we have learned from these spectra and presents 'doorway' references into the literature. Detailed reviews of many aspects of interstellar dust are given.

  5. Quantitative Finance CONTACT INFORMATION

    E-print Network

    Arnold, Elizabeth A.

    Quantitative Finance CONTACT INFORMATION Pamela Peterson Drake, PhD Department Head, Finance of Finance College of Business ZSH 325 (540) 568-8107 finkjd@jmu.edu Michelle Duncan, Advisor Academic Services Center College of Business ZSH 205 (540) 568-3078 duncanml@jmu.edu What is a quantitative finance

  6. Laser Spectroscopy

    NASA Astrophysics Data System (ADS)

    Katori, H.; Yoneda, H.; Nakagawa, K.; Shimizu, F.

    2010-02-01

    Anderson localization of matter-waves in a controlled disorder: a quantum simulator? / A. Aspect ... [et al.] -- Squeezing and entanglement in a Bose-Einstein condensate / C. Gross ... [et al.] -- New physics in dipolar Bose-Einstein condensates / Y. Kawaguchi, H. Saito, and M. Ueda -- Observation of vacuum fluctuations in a spinor Bose-Einstein condensate / C. Klempt ... [et al.] -- Negative-index media for matter waves / F. Perales ... [et al.] -- Entanglement of two individual atoms using the Rydberg blockade / A. Browaeys ... [et al.] -- Array of mesoscopic ensembles on a magnetic atom chip / A. F. Tauschinsky ... [et al.] -- Stability of the proton-to-electron mass ratio tested with molecules using an optical link to primary clock / A. Amy-Klein ... [et al.] -- Metastable helium: lifetime measurements using cold atoms as a test of QED / K. G. H. Baldwin ... [et al.] -- Optical lattice clocks with single occupancy bosons and spin-polarized fermions toward 10[symbol] accuracy / M. Takamoto ... [et al.] -- Frequency measurements of Al[symbol] and Hg[symbol] optical standards / W. M. Itano ... [et al.] -- Switching of light with light using cold atoms inside a hollow optical fiber / M. Bajcsy ... [et al.] -- Room-temperature atomic ensembles for quantum memory and magnetometry / K. Jensen ... [et al.] -- Components for multi-photon non-classical state preparation and measurement / G. Puentes ... [et al.] -- Quantum field state measurement and reconstruction in a cavity by quantum nondemolition photon counting / M. Brune ... [et al.] -- XUV frequency comb spectroscopy / C. Gohle ... [et al.] -- Ultrahigh-repetition-rate pulse train with absolute-phase control produced by an adiabatic raman process / M. Katsuragawa ... [et al.] -- Strongly correlated bosons and fermions in optical lattices / S. Will ... [et al.] -- Bragg spectroscopy of ultracold bose gases in optical lattices / L. Fallani ... [et al.] -- Synthetic quantum many-body systems / C. Guerlin ... [et al.] -- Ultracold Ytterbium atoms in optical lattices / S. Sugawa ... [et al.] -- Ultracold polar molecules in the rovibrational ground state / J. Deiglmayr ... [et al.] -- Polar molecules near quantum degeneracy / J. Ye and D. S. Jin -- Production of a quantum gas of rovibronic ground-state molecules in an optical lattice / J. G. Danzl ... [et al.] -- Recent progress in x-ray nonlinear optics / K. Tamasaku, K. Sawada, and T. Ishikawa -- Gas in scattering media absorption spectroscopy - laser spectroscopy in unconventional environments / S. Svanberg -- Laser spectroscopy on relativistic ion beams / S. Reinhardt ... [et al.] -- Single frequency microcavity lasers and applications / L. Xu ... [et al.].

  7. Combined infrared and ultraviolet-visible spectroscopy matrix-isolated carbon vapor

    NASA Technical Reports Server (NTRS)

    Kurtz, Joe; Huffman, Donald R.

    1990-01-01

    Infrared and UV-visible absorption spectra have been measured on the same sample of matrix-isolated carbon vapor in order to establish correlations between absorption intensities of vibrational and electronic transitions as a function of sample annealing. A high degree of correlation has been found between the IR feature at 1998/cm recently assigned to C8 and a UV absorption feature at about 3100 A. Thus, for the first time, direct evidence is given for the assignment of one of the unknown UV-visible features of the long-studied matrix-isolated carbon vapor spectrum.

  8. SPECTROSCOPY WITH TRAPPED FRANCIUM LUIS A. OROZCO

    E-print Network

    Orozco, Luis A.

    SPECTROSCOPY WITH TRAPPED FRANCIUM LUIS A. OROZCO Department of Physics and Astronomy State of the francium experiments at Stony Brook. The measurements show that the level of quantitative un- derstanding the weak force, in particular about the anapole moment. 2. Francium production and trapping Francium

  9. Diffuse reflectance spectroscopy of fibrous proteins.

    PubMed

    Millington, Keith R

    2012-09-01

    UV-visible diffuse reflectance (DR) spectra of the fibrous proteins wool and feather keratin, silk fibroin and bovine skin collagen are presented. Natural wool contains much higher levels of visible chromophores across the whole visible range (700-400 nm) than the other proteins and only those above 450 nm are effectively removed by bleaching. Both oxidative and reductive bleaching are inefficient for removing yellow chromophores (450-400 nm absorbers) from wool. The DR spectra of the four UV-absorbing amino acids tryptophan, tyrosine, cystine and phenylalanine were recorded as finely ground powders. In contrast to their UV-visible spectra in aqueous solution where tryptophan and tyrosine are the major UV absorbing species, surprisingly the disulphide chromophore of solid cystine has the strongest UV absorbance measured using the DR remission function F(R)(?). The DR spectra of unpigmented feather and wool keratin appear to be dominated by cystine absorption near 290 nm, whereas silk fibroin appears similar to tyrosine. Because cystine has a flat reflectance spectrum in the visible region from 700 to 400 nm and the powder therefore appears white, cystine absorption does not contribute to the cream colour of wool despite the high concentration of cystine residues near the cuticle surface. The disulphide absorption of solid L: -cystine in the DR spectrum at 290 nm is significantly red shifted by ~40 nm relative to its wavelength in solution, whereas homocystine and lipoic acid showed smaller red shifts of 20 nm. The large red shift observed for cystine and the large difference in intensity of absorption in its UV-visible and DR spectra may be due to differences in the dihedral angle between the crystalline solid and the solvated molecules in solution. PMID:22218994

  10. The Quantitative Methods Boot Camp: Teaching Quantitative Thinking and

    E-print Network

    Born, Richard

    biological systems. The boot camp teaches basic programming using biological examples from statistics, image processing, and data analysis. This integrative approach to teaching programming and quantitative reasoningEDUCATION The Quantitative Methods Boot Camp: Teaching Quantitative Thinking and Computing Skills

  11. Matrix photochemistry, photoelectron spectroscopy, solid-phase structure, and ring strain energy of beta-propiothiolactone.

    PubMed

    Dugarte, Nahir Y; Erben, Mauricio F; Romano, Rosana M; Boese, Roland; Ge, Mao-Fa; Li, Yao; Della Védova, Carlos O

    2009-04-16

    The four-membered heterocyclic beta-propiothiolactone compound was isolated in a low-temperature inert Ar matrix, and the UV-visible (200 < or = lambda < or = 800 nm) induced photochemistry was studied. On the basis of the IR spectra, the formation of methylketene (CH(3)CHCO) was identified as the main channel of photodecomposition. The formation of ethene and thiirane, with the concomitant elimination of OCS and CO, respectively, was also observed as minor decomposition channels. The valence electronic structure was investigated by HeI photoelectron spectroscopy assisted by quantum chemical calculations at the OVGF/6-311++G(d,p) level of theory. The first three bands at 9.73, 9.87, and 12.06 eV are ascribed to the n''(S), n'(O), and pi''(CO) orbitals, respectively, denoting the importance of the -SC(O)- group in the outermost electronic properties. Additionally, the structure of a single crystal, grown in situ, was determined by X-ray diffraction analysis at low temperature. The crystalline solid [monoclinic system, P21/c, a = 8.1062(1) A, b = 10.3069(2) A, c = 10.2734(1) A, beta = 107.628(1) degrees, and Z = 8] consists of planar molecules arranged in layers. The skeletal parameters, especially the valence angles [angleC2-C1-S = 94.55(7) degrees, angleOC-C = 134.20(11) degrees, angleC-S-C = 77.27(5) degrees], differ from those typically found in acyclic thioester compounds, suggesting the presence of strong strain effects. The conventional ring strain energy was determined to be 16.4 kcal/mol at the G2MP2 level of calculation within the hyperhomodesmotic model. PMID:19301891

  12. Key Dynamics of Conserved Asparagine in a Cryptochrome/Photolyase Family Protein by FTIR Spectroscopy†

    PubMed Central

    Iwata, Tatsuya; Zhang, Yu; Hitomi, Kenichi; Getzoff, Elizabeth D.; Kandori, Hideki

    2012-01-01

    Cryptochromes (Crys) and photolyases (Phrs) are flavoproteins that contain an identical cofactor (flavin adenine dinucleotide, FAD) within the same protein architecture, but whose physiological functions are entirely different. In this study, we investigated light-induced conformational changes of a cyanobacterium Cry/Phr-like protein (SCry-DASH) with UV–visible and Fourier transform infrared (FTIR) spectroscopy. We developed a system to measure light-induced difference spectra under the concentrated conditions. In the presence of reducing agent, SCry-DASH showed photoreduction to the reduced form, and we identified a signal unique for an anionic form in the process. Difference FTIR spectra enabled us to assign characteristic FTIR bands to the respective redox forms of FAD. An asparagine residue, which anchors the FAD embedded within the protein is conserved in not only the cyanobaterial protein, but also in Phrs and other Crys including the mammalian clock-related Crys. By characterizing an asparagine-to-cysteine (N392C) mutant of SCry-DASH, which mimics an insect specific Cry, we identified structural changes of the carbonyl group of this conserved asparagine upon light-irradiation. We also found that the N392C mutant is stabilized in the anionic form. We did not observe a signal from protonated carboxylic acid residues during the reduction process, suggesting that the carboxylic acid moiety would not be directly involved as a proton donor to FAD in the system. These results are in contrast to plant specific Crys represented by Arabidopsis thaliana Cry1 which carry Asp at the position. We discuss potential roles for this conserved asparagine position and functional diversity in the Cry/Phr frame. PMID:20828134

  13. Femtosecond polarization resolved spectroscopy: A tool for determination of the three-dimensional orientation of electronic transition dipole moments and identification of configurational isomers

    NASA Astrophysics Data System (ADS)

    Theisen, Moritz; Linke, Martin; Kerbs, Max; Fidder, Henk; Madjet, Mohamed El-Amine; Zacarias, Angelica; Heyne, Karsten

    2009-09-01

    A method is presented that combines femtosecond polarization resolved UV/visible pump-IR probe spectroscopy and density functional theory calculations in determining the three-dimensional orientation of an electronic transition dipole moment (tdm) within the molecular structure. The method is demonstrated on the approximately planar molecule coumarin 314 (C314) dissolved in acetonitrile, which can exist in two ground state configurations: the E- and the Z-isomer. Based on an exhaustive search analysis on polarization resolved measurement data for four different vibrational modes, it is concluded that C314 in acetonitrile is the E-isomer. The electronic tdm vector for the electronic S0?S1 transition is determined and the analysis shows that performing the procedure for four vibrational modes instead of the minimally required three reduces the 1? probability area from 2.34% to 2.24% of the solution space. Moreover, the fastest rotational correlation time ?c for the C314 E-isomer is determined to be 26±2 ps.

  14. Synthesis, X-ray crystal structure and spectroscopy of a Werner-type host Co(II) complex, trans-bisisothiocyanatotetrakis( trans-4-styrylpyridine)cobalt(II)

    NASA Astrophysics Data System (ADS)

    Karunakaran, C.; Thomas, K. R. J.; Shunmugasundaram, A.; Murugesan, R.

    2000-05-01

    Single crystals of the title Co(II) complex, [Co(stpy) 4(NCS) 2] [stpy= trans-4-styrylpyridine] are prepared and characterized by elemental analysis, IR, and UV-visible spectroscopy and X-ray crystal structure determination. The complex crystallizes in the orthorhombic space group Pna2 1 with unit-cell parameters, a=32.058(3), b=15.362(5), c=9.818(5) Å, and Z=4. The structure consists of discrete monomeric units of [Co(stpy) 4(NCS) 2]. The equatorial positions of the Co(II) polyhedron are occupied by nitrogen atoms of the four stpy ligands and the axial positions are occupied by the nitrogen atoms of the two thiocyanate ions. The unit cell packing reveals interpenetration of styryl groups owing to conformational flexibility of phenyl and pyridyl rings in stpy ligands. Thus, it leads to efficient packing of the crystal lattice leaving no space available for guest inclusion. IR spectra reveal nitrogen coordination from stpy and terminal -NCS coordination of the thiocyanate group. The optical reflectance bands 475, 540 (shoulder) and 1022 nm suggest octahedral geometry in accordance with the X-ray data. However, the optical spectrum of acetonitrile solution shows an intense band at 615 nm and a weak shoulder at 570 nm suggesting participation of the solvent molecules in the coordination sphere. These bands indicate the presence of both tetrahedral and octahedral species in solution.

  15. Molecular Spectroscopy and Remote-Sensing of the Earth's Atmosphere: Progress from Laboratory Studies

    SciTech Connect

    Orphal, Johannes

    2009-03-11

    In this paper we present some recent developments in the field of molecular spectroscopy applied to the measurement of trace gases in the Earth's atmosphere, in particular concerning the spectroscopy of unstable species or radicals and of isotopic species, but also in the field of quantitative spectroscopy, in the context of more and more challenging requirements arising from modern remote-sensing experiments.

  16. On Quantitative Rorschach Scales.

    ERIC Educational Resources Information Center

    Haggard, Ernest A.

    1978-01-01

    Two types of quantitative Rorschach scales are discussed: first, those based on the response categories of content, location, and the determinants, and second, global scales based on the subject's responses to all ten stimulus cards. (Author/JKS)

  17. Quantitative film radiography

    SciTech Connect

    Devine, G.; Dobie, D.; Fugina, J.; Hernandez, J.; Logan, C.; Mohr, P.; Moss, R.; Schumacher, B.; Updike, E.; Weirup, D.

    1991-02-26

    We have developed a system of quantitative radiography in order to produce quantitative images displaying homogeneity of parts. The materials that we characterize are synthetic composites and may contain important subtle density variations not discernible by examining a raw film x-radiograph. In order to quantitatively interpret film radiographs, it is necessary to digitize, interpret, and display the images. Our integrated system of quantitative radiography displays accurate, high-resolution pseudo-color images in units of density. We characterize approximately 10,000 parts per year in hundreds of different configurations and compositions with this system. This report discusses: the method; film processor monitoring and control; verifying film and processor performance; and correction of scatter effects.

  18. Quantitative Imaging Network

    Cancer.gov

    The QIN Imaging Network is designed to promote research and development of quantitative imaging methods for the measurement of tumor response to therapies in clinical trial settings, with the overall goal of facilitating clinical decision-making. The

  19. Quantitative receptor autoradiography

    SciTech Connect

    Boast, C.A.; Snowhill, E.W.; Altar, C.A.

    1986-01-01

    Quantitative receptor autoradiography addresses the topic of technical and scientific advances in the sphere of quantitative autoradiography. The volume opens with a overview of the field from a historical and critical perspective. Following is a detailed discussion of in vitro data obtained from a variety of neurotransmitter systems. The next section explores applications of autoradiography, and the final two chapters consider experimental models. Methodological considerations are emphasized, including the use of computers for image analysis.

  20. Journal of Quantitative Spectroscopy & Radiative Transfer 105 (2007) 356

    E-print Network

    2007-01-01

    by the incident wave but also by the partial wavelets coming from all the other particles, the partial wavelets that the total scattered field at the observation point can be expressed as a superposition of waves traveling. Chapters 2 and 3 introduce the relevant addition theorems in two and three dimensions while Appendices A

  1. Journal of Quantitative Spectroscopy & Radiative Transfer 109 (2008) 22912302

    E-print Network

    2008-01-01

    -vibrational structure from the spectrum. The spectra obtained were used to retrieve averaged and smoothed binary affects the Earth's outgoing radiation and therefore is of great importance for radiative budget. This continuous absorption is proportional to the square of the water-vapor density and can be considered

  2. Journal of Quantitative Spectroscopy & Radiative Transfer 85 (2004) 367383

    E-print Network

    Kirk-Davidoff, Daniel

    2004-01-01

    of the outgoing thermal radiation to space have, for the past 30 years, occupied an important place the standpoint of climate modeling the requirement is for accurate and reliable averages over signiÿcant regions of the Earth's surface. These averages must be of su cient accuracy to resolve questions that arise in climate

  3. Quantitative Analysis of Cotton Lint Trash by Fluorescence Spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The presence of cotton plant botanical components, or trash, embedded in lint subsequent to harvesting and ginning is an important criterion in the classification of baled cotton by the USDA-Agricultural Marketing Service. The trash particles may be reduced in size to the point that specific trash ...

  4. CONFOCAL MICROSCOPY SYSTEM PERFORMANCE: FOUNDATIONS FOR CALIBRATION, QUANTITATION AND SPECTROSCOPY

    EPA Science Inventory

    The confocal laser-scanning microscope (CLSM) has enormous potential in many biological fields. The goal of a CLSM is to acquire and quantify fluorescence and in some instruments acquire spectral characterization of emitted signals. The accuracy of these measurements demands that...

  5. Clinical feasibility of Raman spectroscopy for quantitative blood glucose measurement

    E-print Network

    Kong, Chae-Ryon

    2011-01-01

    Diabetes mellitus is a leading cause of morbidity and mortality worldwide, and close monitoring of blood glucose levels is crucial for its diagnosis and management. Currently, blood glucose monitoring is done by blood ...

  6. Quantitative spectroscopy for the analysis of GOME data

    NASA Technical Reports Server (NTRS)

    Chance, K.

    1997-01-01

    Accurate analysis of the global ozone monitoring experiment (GOME) data to obtain atmospheric constituents requires reliable, traceable spectroscopic parameters for atmospheric absorption and scattering. Results are summarized for research that includes: the re-determination of Rayleigh scattering cross sections and phase functions for the 200 nm to 1000 nm range; the analysis of solar spectra to obtain a high-resolution reference spectrum with excellent absolute vacuum wavelength calibration; Ring effect cross sections and phase functions determined directly from accurate molecular parameters of N2 and O2; O2 A band line intensities and pressure broadening coefficients; and the analysis of absolute accuracies for ultraviolet and visible absorption cross sections of O3 and other trace species measurable by GOME.

  7. Quantitative analysis of ice films by near-infrared spectroscopy

    NASA Technical Reports Server (NTRS)

    Keiser, Joseph T.

    1990-01-01

    One of the outstanding problems in the Space Transportation System is the possibility of the ice buildup on the external fuel tank surface while it is mounted on the launch pad. During the T-2 hours (and holding) period, the frost/ice thickness on the external tank is monitored/measured. However, after the resumption of the countdown time, the tank surface can only be monitored remotely. Currently, remote sensing is done with a TV camera coupled to a thermal imaging device. This device is capable of identifying the presence of ice, especially if it is covered with a layer of frost. However, it has difficulty identifying transparent ice, and, it is not capable of determining the thickness of ice in any case. Thus, there is a need for developing a technique for measuring the thickness of frost/ice on the tank surface during this two hour period before launch. The external tank surface is flooded with sunlight (natural or simulated) before launch. It may be possible, therefore, to analyze the diffuse reflection of sunlight from the external tank to determine the presence and thickness of ice. The purpose was to investigate the feasibility of this approach. A near-infrared spectrophotometer was used to record spectra of ice. It was determined that the optimum frequencies for monitoring the ice films were 1.03 and 1.255 microns.

  8. CONFOCAL MICROSCOPY SYSTEM PERFORMANCE: FOUNDATIONS FOR MEASUREMENTS, QUANTITATION AND SPECTROSCOPY

    EPA Science Inventory

    The confocal laser-scanning microscopy (CLSM) has enormous potential in many biological fields. The goal of a CLSM is to acquire and quantify fluorescence and in some instruments acquire spectral characterization of the emitted signal. The accuracy of these measurements demands t...

  9. Journal of Quantitative Spectroscopy & Radiative Transfer 99 (2006) 341348

    E-print Network

    2006-01-01

    by 100 ns implosions of wire arrays or gas puffs produce substantial soft X-ray power. One class of z 1. Introduction Pulsed-power-driven fast z-pinches are efficient generators of soft X-rays, with $15 Research Laboratory, Washington, DC 20375, USA d Faculty of Physics, Weizmann Institute of Science, 76100

  10. Journal of Quantitative Spectroscopy & Radiative Transfer 108 (2007) 389402

    E-print Network

    Gamache, Robert R.

    2007-01-01

    for Astrophysics, Atomic and Molecular Physics Division, Cambridge, MA 02138-1516, USA b University of Mass. Lowell, the line intensity, the Einstein A-coefficient and statistical weights, the air- broadened half-width (gair

  11. Direct and quantitative broadband absorptance spectroscopy with multilayer cantilever probes

    DOEpatents

    Hsu, Wei-Chun; Tong, Jonathan Kien-Kwok; Liao, Bolin; Chen, Gang

    2015-04-21

    A system for measuring the absorption spectrum of a sample is provided that includes a broadband light source that produces broadband light defined within a range of an absorptance spectrum. An interferometer modulates the intensity of the broadband light source for a range of modulation frequencies. A bi-layer cantilever probe arm is thermally connected to a sample arm having at most two layers of materials. The broadband light modulated by the interferometer is directed towards the sample and absorbed by the sample and converted into heat, which causes a temperature rise and bending of the bi-layer cantilever probe arm. A detector mechanism measures and records the deflection of the probe arm so as to obtain the absorptance spectrum of the sample.

  12. Journal of Quantitative Spectroscopy & Radiative Transfer 99 (2006) 165174

    E-print Network

    Rocca, Jorge J.

    2006-01-01

    Lawrence Livermore National Laboratory, Livermore, CA 94550, USA c Department of Applied Science, University of California Davis-Livermore, Livermore, CA 94451, USA Accepted 26 April 2005 Abstract We report

  13. Reflectance spectroscopy: quantitative analysis techniques for remote sensing applications.

    USGS Publications Warehouse

    Clark, R.N.; Roush, T.L.

    1984-01-01

    Several methods for the analysis of remotely sensed reflectance data are compared, including empirical methods and scattering theories, both of which are important for solving remote sensing problems. The concept of the photon mean path length and the implications for use in modeling reflectance spectra are presented.-from Authors

  14. Journal of Quantitative Spectroscopy & Radiative Transfer 71 (2001) 157168

    E-print Network

    Cohen, David

    2001-01-01

    .elsevier.com/locate/jqsrt Neon photoionization experiments driven by Z-pinch radiation J.E. Baileya; , D. Cohenb;e , G Computational Science, Madison, WI 53703, USA Abstract Present-day Z-pinch experiments generate 2 × 1021 erg galactic nuclei. Moreover, this information is needed for X-ray laser research. Our experiments use a 1-cm

  15. CONFOCAL MICROSCOPY SYSTEM PERFORMANCE: SPECTROSCOPY AND FOUNDATIONS FOR QUANTITATION

    EPA Science Inventory

    The confocal laser-scanning microscope (CLSM) has enormous potential in many biological fields. The reliability of the CLSM to obtain specific measurements and quantify fluorescence data is dependent on using a correctly aligned machine that contains a stable laser power. For man...

  16. Journal of Quantitative Spectroscopy & Radiative Transfer 106 (2007) 417436

    E-print Network

    Draine, Bruce T.

    2007-01-01

    either Mie, T-matrix or cluster T-Matrix codes with suitable geometries. It is found that the relative scattering studies is very large because at its best all the 16 Mueller matrix ARTICLE IN PRESS www categories: those which use the ray optics (RO) or geometric optics (GO) approaches and those which use

  17. Current status of quantitative rotational spectroscopy for atmospheric research

    NASA Technical Reports Server (NTRS)

    Drouin, Brian J.; Wlodarczak, Georges; Colmont, Jean-Marcel; Rohart, Francois

    2004-01-01

    Remote sensing of rotational transitions in the Earth's atmosphere has become an important method for the retrieval of geophysical temperatures, pressures and chemical composition profiles that requires accurate spectral information. This paper highlights the current status of rotational data that are useful for atmospheric measurements, with a discussion of the types the rotational lineshape measurements that are not generally available in either online repository.

  18. Journal of Quantitative Spectroscopy & Radiative Transfer 104 (2007) 384399

    E-print Network

    Pilon, Laurent

    2007-01-01

    : Transient radiative transfer; Method of characteristics; Scattering; Turbid media; Biological tissues-resolved hemispherical reflectance of absorbing and isotropically scattering media Kyle D. Smith, Kamal M. Katika, absorbing, and isotropically scattering medium exposed to a collimated Gaussian pulse. The front surface

  19. Journal of Quantitative Spectroscopy & Radiative Transfer 101 (2006) 488497

    E-print Network

    2006-01-01

    crystals can be negligible. r 2006 Elsevier Ltd. All rights reserved. Keywords: Cirrus clouds; Scattering; Remote sensing; Atmospheric radiation 1. Introduction Cirrus clouds play an important role in the earth and by reflecting and absorbing incoming short-wave solar radiation. However, cirrus clouds remain a significant

  20. Quantitative WDS analysis using electron probe microanalyzer

    SciTech Connect

    Ul-Hamid, Anwar . E-mail: anwar@kfupm.edu.sa; Tawancy, Hani M.; Mohammed, Abdul-Rashid I.; Al-Jaroudi, Said S.; Abbas, Nureddin M.

    2006-04-15

    In this paper, the procedure for conducting quantitative elemental analysis by ZAF correction method using wavelength dispersive X-ray spectroscopy (WDS) in an electron probe microanalyzer (EPMA) is elaborated. Analysis of a thermal barrier coating (TBC) system formed on a Ni-based single crystal superalloy is presented as an example to illustrate the analysis of samples consisting of a large number of major and minor elements. The analysis was performed by known standards and measured peak-to-background intensity ratios. The procedure for using separate set of acquisition conditions for major and minor element analysis is explained and its importance is stressed.

  1. Qualitative and quantitative analysis of mixtures of compounds containing both hydrogen and deuterium

    NASA Technical Reports Server (NTRS)

    Crespi, H. L.; Harkness, L.; Katz, J. J.; Norman, G.; Saur, W.

    1969-01-01

    Method allows qualitative and quantitative analysis of mixtures of partially deuterated compounds. Nuclear magnetic resonance spectroscopy determines location and amount of deuterium in organic compounds but not fully deuterated compounds. Mass spectroscopy can detect fully deuterated species but not the location.

  2. Spectroscopy for Detection of Cancer

    NASA Astrophysics Data System (ADS)

    Georgakoudi, Irene

    2001-03-01

    Our work focuses on the development and application of three techniques -intrinsic fluorescence, diffuse reflectance and light scattering spectroscopy- as tools for the biophysical characterization of tissues. Our aim is to use these three spectroscopic techniques in combination (Tri-Modal Spectroscopy) for extracting information related to the biochemical, structural and morphological state of the uppermost layers of tissue, where almost 90cancers start. Fluorescence spectroscopy bears the signatures of native tissue chromophores such as NADH, porphyrins and collagen. However, tissue is a turbid medium with significant levels of scattering and absorption, which can distort the native (intrinsic) fluorescence signal. To remove these distortions we combine information in measured fluorescence and diffuse reflectance spectra using a photon migration based picture. The extracted intrinsic fluorescence spectra can be decomposed to provide quantitative information on the biochemical tissue composition and the changes that take place during the development of dysplasia, a pre-cancerous condition. Diffuse reflectance spectra can be analyzed using a model based on light diffusion theory to determine the values of the absorption and reduced scattering coefficients of tissue, which can be also modified during dysplastic progression. Finally, light scattering spectroscopy provides information on the size and number density of the nuclei of the epithelial cell layer, two important diagnostic parameters employed by pathologists for tissue classification. Since each one of these techniques provides complementary information on tissue biochemistry and morphology, their combined use serves as an excellent tool for biophysical tissue characterization and the detection of pre-cancerous lesions.

  3. Mössbauer Spectroscopy on Compounds of Biomedical Interests

    NASA Astrophysics Data System (ADS)

    Oliver, F.; Ewing, N.; Hoffman, E.; Kinyua, A.; Oladeinde, F.; Murdock, A.

    2006-03-01

    Mössbauer spectroscopy (nuclear gamma resonance spectroscopy)^1 has been used in our laboratory for many biomedical applications. This presentation will demonstrate uses of Mössbauer spectroscopy to obtain qualitative and quantitative information about the electronic and magnetic properties of various systems. Information is obtained related to the electronic spin, electric quadrupole interaction, and magnetic hyperfine interactions. This technique has a very broad spectrum of applications, most of them in solid state physics and chemistry. Experiments may be done using transmission or backscattering geometry. For the past fifteen years we have successfully applied this technique to investigate materials of biomedical interest. Materials investigated include porphyrins containing europium^2, plants, over the counter medicines, hemoglobin, and ion implanted implant materials. Results of these experiments and other possible applications will be reported. 1. Leopold May, An Introduction to Mössbauer Spectroscopy, Plenum Press Z(1971). 2. Oliver, et al., Inorganica Chimica Acta, Vol. 186, 119 (1991). * Partially supported by NIH, ** Partially supported by NSF-SEM program.

  4. Quantitative photoacoustic tomography

    PubMed Central

    Yuan, Zhen; Jiang, Huabei

    2009-01-01

    In this paper, several algorithms that allow for quantitative photoacoustic reconstruction of tissue optical, acoustic and physiological properties are described in a finite-element method based framework. These quantitative reconstruction algorithms are compared, and the merits and limitations associated with these methods are discussed. In addition, a multispectral approach is presented for concurrent reconstructions of multiple parameters including deoxyhaemoglobin, oxyhaemoglobin and water concentrations as well as acoustic speed. Simulation and in vivo experiments are used to demonstrate the effectiveness of the reconstruction algorithms presented. PMID:19581254

  5. Critical Quantitative Inquiry in Context

    ERIC Educational Resources Information Center

    Stage, Frances K.; Wells, Ryan S.

    2014-01-01

    This chapter briefly traces the development of the concept of critical quantitative inquiry, provides an expanded conceptualization of the tasks of critical quantitative research, offers theoretical explanation and justification for critical research using quantitative methods, and previews the work of quantitative criticalists presented in this…

  6. Amateur spectroscopy

    NASA Astrophysics Data System (ADS)

    Gavin, M. V.

    1998-06-01

    (The 1997 Presidential Address to the British Astronomical Association.) Auguste Comte is remembered for an unfortunate remark. In 1825 he said the chemical composition of stars would never be revealed. Within a decade or so the heart of the atom was being explored in remote stars through the science of spectroscopy. In simplistic terms one can regard the atom as a miniature solar system, but with the novel option that electrons (representing planets) having the ability to 'jump' from one orbit to another. In 'falling' to a lower orbit a photon of light of precise wavelength is released to travel outwards. When the electron 'jumps' to a higher orbit a photon of light is absorbed. This is taking place on a vast scale which we observe as lines in the spectrum - their position and prominence relates to the particular atomic element, temperature and pressure within the stellar atmosphere. It is beyond the scope of this Address to discuss the various processes that affect spectra, or to provide a mathematical explanation which can be found elsewhere. In any case the lack of a deep understanding does not preclude enjoyable or useful observations. Methods and results from amateurs conducting such observations are discussed in this paper.

  7. Planetary spectroscopy

    NASA Astrophysics Data System (ADS)

    Fink, Uwe

    1988-08-01

    The main goal of the research is charge coupled device (CCD) spectroscopic and imaging studies of the solar system in support of spacecraft investigations. Studies include the physical behavior of comets, the atmosphere of the gaseous planets, and the solid surfaces of satellites and asteroids. The major observing program consisted of approximately 50 nights of photometry of Comet Halley in order to resolve the controversy over this comet's rotation period. This data is presently being analyzed. Additional observing projects included the spectroscopic occultation of Charon by Pluto, reflection spectroscopy of Mercury, and a spectrum of the satellite Oberon. Mercury data does not corroborate the Fe(++) absorption feature reported by McCord and Clark at 8800 A but instead potentially shows a weaker feature at longer wavelengths. This position is in much closer accord with expectations for Mercury since a band center near 8800 A implies too little Fe(++) on Mercury, especially if band shifts with temperature are considered. The Pluto project proved that the deep methane absorptions visible in their combined specta are due soley to Pluto with Charon showing a flat and featureless spectrum. It appears that if Charon ever contained a substantial methane component, the satellite's low surface gravity could not hold it and the methane evaporated and escaped.

  8. Planetary spectroscopy

    NASA Technical Reports Server (NTRS)

    Fink, Uwe

    1988-01-01

    The main goal of the research is charge coupled device (CCD) spectroscopic and imaging studies of the solar system in support of spacecraft investigations. Studies include the physical behavior of comets, the atmosphere of the gaseous planets, and the solid surfaces of satellites and asteroids. The major observing program consisted of approximately 50 nights of photometry of Comet Halley in order to resolve the controversy over this comet's rotation period. This data is presently being analyzed. Additional observing projects included the spectroscopic occultation of Charon by Pluto, reflection spectroscopy of Mercury, and a spectrum of the satellite Oberon. Mercury data does not corroborate the Fe(++) absorption feature reported by McCord and Clark at 8800 A but instead potentially shows a weaker feature at longer wavelengths. This position is in much closer accord with expectations for Mercury since a band center near 8800 A implies too little Fe(++) on Mercury, especially if band shifts with temperature are considered. The Pluto project proved that the deep methane absorptions visible in their combined specta are due soley to Pluto with Charon showing a flat and featureless spectrum. It appears that if Charon ever contained a substantial methane component, the satellite's low surface gravity could not hold it and the methane evaporated and escaped.

  9. SIMP Spectroscopy

    E-print Network

    Yonit Hochberg; Eric Kuflik; Hitoshi Murayama

    2015-12-24

    We study the interactions between strongly interacting massive particle dark matter and the Standard Model via a massive vector boson that is kinetically mixed with the hypercharge gauge boson. The relic abundance is set by 3-to-2 self-interactions of the dark matter, while the interactions with the vector mediator enable kinetic equilibrium between the dark and visible sectors. We show that a wide range of parameters is phenomenologically viable and can be probed in various ways. Astrophysical and cosmological constraints are evaded due to the p-wave nature of dark matter annihilation into visible particles, while direct detection methods using electron recoils can be sensitive to parts of the parameter space. In addition, we propose performing spectroscopy of the strongly coupled dark sector at e+e- colliders, where the energy of a mono-photon can track the resonance structure of the dark sector. Alternatively, some resonances may decay back into Standard Model leptons or jets, realizing `hidden valley' phenomenology at the LHC and ILC in a concrete fashion.

  10. Quantitative Decision Making.

    ERIC Educational Resources Information Center

    Baldwin, Grover H.

    The use of quantitative decision making tools provides the decision maker with a range of alternatives among which to decide, permits acceptance and use of the optimal solution, and decreases risk. Training line administrators in the use of these tools can help school business officials obtain reliable information upon which to base district…

  11. Leadership In Quantitative Excellence

    E-print Network

    Frey, Robert J.

    Darnell, Managing Director, GMO Eric Wepsic, Managing Director, DE Shaw #12;Presents Leadership for the development, trading, risk management, and marketing of quantitative long-short, long-only, and overlay focus is the process by which capital markets incorporate information about future cash flows and risks

  12. Quantitative Simulation Games

    NASA Astrophysics Data System (ADS)

    ?erný, Pavol; Henzinger, Thomas A.; Radhakrishna, Arjun

    While a boolean notion of correctness is given by a preorder on systems and properties, a quantitative notion of correctness is defined by a distance function on systems and properties, where the distance between a system and a property provides a measure of "fit" or "desirability." In this article, we explore several ways how the simulation preorder can be generalized to a distance function. This is done by equipping the classical simulation game between a system and a property with quantitative objectives. In particular, for systems that satisfy a property, a quantitative simulation game can measure the "robustness" of the satisfaction, that is, how much the system can deviate from its nominal behavior while still satisfying the property. For systems that violate a property, a quantitative simulation game can measure the "seriousness" of the violation, that is, how much the property has to be modified so that it is satisfied by the system. These distances can be computed in polynomial time, since the computation reduces to the value problem in limit average games with constant weights. Finally, we demonstrate how the robustness distance can be used to measure how many transmission errors are tolerated by error correcting codes.

  13. Insights into the mechanism of X-ray-induced disulfide-bond cleavage in lysozyme crystals based on EPR, optical absorption and X-ray diffraction studies

    SciTech Connect

    Sutton, Kristin A.; Black, Paul J.; Mercer, Kermit R.; Garman, Elspeth F.; Owen, Robin L.; Snell, Edward H.; Bernhard, William A.

    2013-12-01

    Electron paramagnetic resonance (EPR) and online UV–visible absorption microspectrophotometry with X-ray crystallography have been used in a complementary manner to follow X-ray-induced disulfide-bond cleavage, to confirm a multi-track radiation-damage process and to develop a model of that process. Electron paramagnetic resonance (EPR) and online UV–visible absorption microspectrophotometry with X-ray crystallography have been used in a complementary manner to follow X-ray-induced disulfide-bond cleavage. Online UV–visible spectroscopy showed that upon X-irradiation, disulfide radicalization appeared to saturate at an absorbed dose of approximately 0.5–0.8 MGy, in contrast to the saturating dose of ?0.2 MGy observed using EPR at much lower dose rates. The observations suggest that a multi-track model involving product formation owing to the interaction of two separate tracks is a valid model for radiation damage in protein crystals. The saturation levels are remarkably consistent given the widely different experimental parameters and the range of total absorbed doses studied. The results indicate that even at the lowest doses used for structural investigations disulfide bonds are already radicalized. Multi-track considerations offer the first step in a comprehensive model of radiation damage that could potentially lead to a combined computational and experimental approach to identifying when damage is likely to be present, to quantitate it and to provide the ability to recover the native unperturbed structure.

  14. Quantitative sensory testing.

    PubMed

    Soomekh, David

    2006-07-01

    The diagnosis and treatment of peripheral neuropathy from any cause has come to the forefront of the research community in the past few years. Both past and new diagnostic and treatment options have been and are being studied to better understand and properly treat this debilitating and sometimes devastating disease. One such advancement is the clinical use of quantitative sensory testing. To identify etiology of the neuropathy early, the testing instrument would need to identify changes throughout the course of the disease, have a normative database, and show a clear distinction between the absence or presence of disease. The pressure specified sensory device (PSSD) was developed in 1992 to painlessly investigate the cutaneous pressure thresholds quantitatively and accurately. PMID:16958387

  15. Berkeley Quantitative Genome Browser

    Energy Science and Technology Software Center (ESTSC)

    2008-02-29

    The Berkeley Quantitative Genome Browser provides graphical browsing functionality for genomic data organized, at a minimum, by sequence and position. While supporting the annotation browsing features typical of many other genomic browsers, additional emphasis is placed on viewing and utilizing quantitative data. Data may be read from GFF, SGR, FASTA or any column delimited format. Once the data has been read into the browser's buffer, it may be searched. filtered or subjected to mathematical transformation.more »The browser also supplies some graphical design manipulation functionality geared towards preparing figures for presentations or publication. A plug-in mechanism enables development outside the core functionality that adds more advanced or esoteric analysis capabilities. BBrowse's development and distribution is open-source and has been built to run on Linux, OSX and MS Windows operating systems.« less

  16. Quantitative criteria for insomnia.

    PubMed

    Lichstein, K L; Durrence, H H; Taylor, D J; Bush, A J; Riedel, B W

    2003-04-01

    Formal diagnostic systems (DSM-IV, ICSD, and ICD-10) do not provide adequate quantitative criteria to diagnose insomnia. This may not present a serious problem in clinical settings where extensive interviews determine the need for clinical management. However, lack of standard criteria introduce disruptive variability into the insomnia research domain. The present study reviewed two decades of psychology clinical trials for insomnia to determine common practice with regard to frequency, severity, and duration criteria for insomnia. Modal patterns established frequency (> or =3 nights a week) and duration (> or =6 months) standard criteria. We then applied four versions of severity criteria to a random sample and used sensitivity-specificity analyses to identify the most valid criterion. We found that severity of sleep onset latency or wake time after sleep onset of: (a) > or =31 min; (b) occurring > or =3 nights a week; (c) for > or =6 months are the most defensible quantitative criteria for insomnia. PMID:12643966

  17. Energy & Climate: Getting Quantitative

    NASA Astrophysics Data System (ADS)

    Wolfson, Richard

    2011-11-01

    A noted environmentalist claims that buying an SUV instead of a regular car is energetically equivalent to leaving your refrigerator door open for seven years. A fossil-fuel apologist argues that solar energy is a pie-in-the-sky dream promulgated by na"ive environmentalists, because there's nowhere near enough solar energy to meet humankind's energy demand. A group advocating shutdown of the Vermont Yankee nuclear plant claims that 70% of its electrical energy is lost in transmission lines. Around the world, thousands agitate for climate action, under the numerical banner ``350.'' Neither the environmentalist, the fossil-fuel apologist, the antinuclear activists, nor most of those marching under the ``350'' banner can back up their assertions with quantitative arguments. Yet questions about energy and its environmental impacts almost always require quantitative answers. Physics can help! This poster gives some cogent examples, based on the newly published 2^nd edition of the author's textbook Energy, Environment, and Climate.

  18. Quantitatively Probing the Al Distribution in Zeolites

    SciTech Connect

    Vjunov, Aleksei; Fulton, John L.; Huthwelker, Thomas; Pin, Sonia; Mei, Donghai; Schenter, Gregory K.; Govind, Niranjan; Camaioni, Donald M.; Hu, Jian Z.; Lercher, Johannes A.

    2014-06-11

    The degree of substitution of Si4+ by Al3+ in the oxygen-terminated tetrahedra (Al T-sites) of zeolites determines the concentration of ion-exchange and Brønsted acid sites. As the location of the tetrahedra and the associated subtle variations in bond angles influence the acid strength, quantitative information about Al T-sites in the framework is critical to rationalize catalytic properties and to design new catalysts. A quantitative analysis is reported that uses a combination of extended X-ray absorption fine structure (EXAFS) analysis and 27Al MAS NMR spectroscopy supported by DFT-based molecular dynamics simulations. To discriminate individual Al atoms, sets of ab initio EXAFS spectra for various T-sites are generated from DFT-based molecular dynamics simulations allowing quantitative treatment of the EXAFS single- and multiple-photoelectron scattering processes out to 3-4 atom shells surrounding the Al absorption center. It is observed that identical zeolite types show dramatically different Al-distributions. A preference of Al for T-sites that are part of one or more 4-member rings in the framework over those T-sites that are part of only 5- and 6-member rings in the HBEA150 sample has been determined from a combination of these methods. This work was supported by the U. S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences.

  19. Primary enzyme quantitation

    DOEpatents

    Saunders, G.C.

    1982-03-04

    The disclosure relates to the quantitation of a primary enzyme concentration by utilizing a substrate for the primary enzyme labeled with a second enzyme which is an indicator enzyme. Enzyme catalysis of the substrate occurs and results in release of the indicator enzyme in an amount directly proportional to the amount of primary enzyme present. By quantifying the free indicator enzyme one determines the amount of primary enzyme present.

  20. Characterization of UV-visible filters for the Wide Field Camera 3 of the Hubble Space Telescope

    NASA Astrophysics Data System (ADS)

    Raouf, Nasrat A.; Trauger, John T.

    2003-02-01

    A set of 48 ultraviolet-visible filters in the Wide Field Camera 3 will be deployed on the Hubble Space Telescope in 2004. We summarize the specifications for the filters, derived through interaction with the Science Oversight Committee. A detailed characterization of the 48 filters is presented.

  1. FTIR, FT-Raman, UV-Visible spectra and quantum chemical calculations of allantoin molecule and its hydrogen bonded dimers

    NASA Astrophysics Data System (ADS)

    Alam, Mohammad Jane; Ahmad, Shabbir

    2015-02-01

    FTIR, FT-Raman and electronic spectra of allantoin molecule are recorded and investigated using DFT and MP2 methods with 6-311++G(d,p) basis set. The molecular structure, anharmonic vibrational spectra, natural atomic charges, non-linear optical properties, etc. have been computed for the ground state of allantoin. The anharmonic vibrational frequencies are calculated using PT2 algorithm (Barone method) as well as VSCF and CC-VSCF methods. These methods yield results that are in remarkable agreement with the experiment. The coupling strengths between pairs of modes are also calculated using coupling integral based on 2MR-QFF approximation. The simulations on allantoin dimers have been also performed at B3LYP/6-311++G(d,p) level of theory to investigate the effect of the intermolecular interactions on the molecular structure and vibrational frequencies of the monomer. Vibrational assignments are made with the great accuracy using PED calculations and animated modes. The combination and overtone bands have been also identified in the FTIR spectrum with the help of anharmonic computations. The electronic spectra are simulated in gas and solution at TD-B3LYP/6-311++G(d,p) level of theory. The important global quantities such as electro-negativity, electronic chemical potential, electrophilicity index, chemical hardness and softness based on HOMO, LUMO energy eigenvalues are also computed. NBO analysis has been performed for monomer and dimers of allantoin at B3LYP/6-311++G(d,p) level of theory.

  2. New performances of the UV-visible spectrometer "SALOMON" dedicated to measurements of night-time stratospheric trace gas species

    NASA Astrophysics Data System (ADS)

    Berthet, Gwenael; Renard, Jean-Baptiste; Chartier, Michel; Robert, Claude; Pirre, Michel; Pommereau, Jean-Pierre; Goutail, Florence; François, Pierre

    2001-08-01

    The light balloon-borne spectrometer SALOMON performs night-time observations of O3, NO2, NO3, OClO and aerosols using the Moon as light source. Four flights have occurred since the first one on October 1998 and have allowed to obtain vertical profiles of the species at mid and high latitude. Since the first flight, the performances concerning the pointing system, the spectral domain (340-700 nm) and the transmission of the instrument have been significantly improved. In particular, the increase of the optical system transmission has allowed to perform measurements during low flux Moon phases and to obtain a better retrieval of OClO contribution. The sensitivity of SALOMON allows to measure species absorption lines corresponding to mixing ratios of a few pptv. It appears that this sensitivity is better than the accuracy of the absorption cross-sections of the species measured in laboratories. Therefore, new laboratory measurements of these cross-sections especially at low temperatures are necessary.

  3. Instrument Design of the Large Aperture Solar UV Visible and IR Observing Telescope (SUVIT) for the SOLAR-C Mission

    NASA Astrophysics Data System (ADS)

    Suematsu, Y.; Katsukawa, Y.; Shimizu, T.; Ichimoto, K.; Takeyama, N.

    2012-12-01

    We present an instrumental design of one major solar observation payload planned for the SOLAR-C mission: the Solar Ultra-violet Visible and near IR observing Telescope (SUVIT). The SUVIT is designed to provide high-angular-resolution investigation of the lower solar atmosphere, from the photosphere to the uppermost chromosphere, with enhanced spectroscopic and spectro-polarimetric capability in wide wavelength regions from 280 nm (Mg II h&k lines) to 1100 nm (He I 1083 nm line) with 1.5 m class aperture and filtergraphic and spectrographic instruments.

  4. A rapid method to estimate the concentration of citrate capped silver nanoparticles from UV-visible light spectra.

    PubMed

    Paramelle, D; Sadovoy, A; Gorelik, S; Free, P; Hobley, J; Fernig, D G

    2014-10-01

    We present a generalized table of extinction coefficient data for silver nanoparticles from 8 to 100 nm. This table allows for easy and quick estimation of the concentration and size of modified and mono-dispersed silver nanoparticles from their optical spectra. We obtained data by determining the silver content of citrate-stabilised silver nanoparticles using sodium cyanide to dissolve the nanoparticles, and measuring solution conductivity with a pH meter and a cyanide-ion selective electrode. The quantification of the silver ion concentration enabled the calculation of extinction coefficients. Experimentally calculated extinction coefficients, in the current work, are in good agreement with collated literature values measured by different authors with non-standardized methodology and each for a limited range of particle size. They are also in good agreement with our theoretical calculations using Mie theory. Thus, we provide a highly standardized and comprehensive tabulated reference data-set. PMID:25096538

  5. Polar twilight UV-visible radiation field: Perturbations due to multiple scattering, ozone depletion, stratospheric clouds, and surface albedo

    SciTech Connect

    Anderson, D.E., Jr. ); Lloyd, S.A. )

    1990-05-20

    The polar twilight atmosphere is different from that at mid-latitude in several ways which lead to significant changes in the wavelength-dependent radiation field. Ozone depletion in the stratosphere leads to increased scattering below 340 nm. Polar stratospheric clouds produce changes in the radiation field which depend on cloud height and thickness. A surface albedo near unity produces a large increase in scattering. Multiple scattering becomes a larger percentage of the radiation field as solar zenith angle increases. These perturbations on the radiation field lead to enhanced ozone destruction in the stratosphere, increased surface irradiance, and a significant wavelength-dependent increase in nadir radiance.

  6. Stabilization of diketo tautomer of curcumin by premicellar anionic surfactants: UV-Visible, fluorescence, tensiometric and TD-DFT evidences

    NASA Astrophysics Data System (ADS)

    Dutta, Anisha; Boruah, Bornali; Manna, Arun K.; Gohain, Biren; Saikia, Palash M.; Dutta, Robin K.

    2013-03-01

    A newly observed UV band of aqueous curcumin, a biologically important molecule, in presence of anionic surfactants, viz., sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), and sodium dodecylsulfonate (SDSN) in buffered aqueous solutions has been studied experimentally and theoretically. The 425 nm absorption band of curcumin disappears and a new UV-band is observed at 355 nm on addition of the surfactants in the submicellar concentration range which is reversed as the surfactant concentration approaches the critical micelle concentration (CMC). The observed spectral absorption, fluorescence intensity and surface tension behavior, under optimal experimental conditions of submicellar concentration ranges of the surfactants in the pH range of 2.00-7.00, indicate that the new band is due to the ?-diketo tautomer of curcumin stabilized by interactions between curcumin and the anionic surfactants. The stabilization of the diketo tautomer by submicellar anionic surfactants described here as well as by submicellar cationic surfactant, reported recently, is unique as this is the only such behavior observed in presence of submicellar surfactants of both charge types. The experimental results are in good agreement with the theoretical calculations using ab initio density functional theory combined with time dependent density functional theory (TD-DFT) calculations.

  7. Computational vaccinology: quantitative approaches.

    PubMed

    Flower, Darren R; McSparron, Helen; Blythe, Martin J; Zygouri, Christianna; Taylor, Debra; Guan, Pingping; Wan, Shouzhan; Coveney, Peter V; Walshe, Valerie; Borrow, Persephone; Doytchinova, Irini A

    2003-01-01

    The immune system is hierarchical and has many levels, exhibiting much emergent behaviour. However, at its heart are molecular recognition events that are indistinguishable from other types of biomacromolecular interaction. These can be addressed well by quantitative experimental and theoretical biophysical techniques, and particularly by methods from drug design. We review here our approach to computational immunovaccinology. In particular, we describe the JenPep database and two new techniques for T cell epitope prediction. One is based on quantitative structure-activity relationships (a 3D-QSAR method based on CoMSIA and another 2D method based on the Free-Wilson approach) and the other on atomistic molecular dynamic simulations using high performance computing. JenPep (http://www.jenner.ar.uk/ JenPep) is a relational database system supporting quantitative data on peptide binding to major histocompatibility complexes, TAP transporters, TCR-pMHC complexes, and an annotated list of B cell and T cell epitopes. Our 2D-QSAR method factors the contribution to peptide binding from individual amino acids as well as 1-2 and 1-3 residue interactions. In the 3D-QSAR approach, the influence of five physicochemical properties (volume, electrostatic potential, hydrophobicity, hydrogen-bond donor and acceptor abilities) on peptide affinity were considered. Both methods are exemplified through their application to the well-studied problem of peptide binding to the human class I MHC molecule HLA-A*0201. PMID:14712934

  8. Surface enhanced vibrational spectroscopy and first-principles study of L-cysteine adsorption on noble trimetallic Au/Pt@Rh clusters.

    PubMed

    Loganathan, B; Chandraboss, V L; Senthilvelan, S; Karthikeyan, B

    2015-09-01

    The Rh shell of the Au/Pt/Rh trimetallic nanoparticles induces a wide variety of interesting surface reactions by allowing the adsorption of amino acids like L-cysteine (L-Cys). We present a snapshot of theoretical and experimental investigation of L-Cys adsorption on the surface of noble trimetallic Au/Pt@Rh colloidal nanocomposites. Density functional theoretical (DFT) investigations of L-Cys interaction with the Rhodium (Rh) shell of a trimetallic Au/Pt@Rh cluster in terms of geometry, binding energy (E(B)), binding site, energy gap (E(g)), electronic and spectral properties have been performed. L-Cys establishes a strong interaction with the Rh shell. It binds to Rh by the S1-site, which makes a stable L-Cys-Rh surface complex. DFT can be taken as a valuable tool to assign the vibrational spectra of the adsorption of L-Cys on trimetallic Au/Pt@Rh colloidal nanocomposites and mono-metallic Rh nanoparticles. Surface-enhanced infrared spectroscopy (SEIRS) with L-Cys on a Rh6 cluster surface has been simulated for the first time. Experimental information on the L-Cys-Rh surface complex is included to examine the interaction. The experimental spectral observations are in good agreement with the simulated DFT results. Characterization of the synthesized trimetallic Au/Pt@Rh colloidal nanocomposites has been done by high-resolution transmission electron microscopy (HR-TEM) with selected area electron diffraction (SAED) pattern, energy dispersive X-ray (EDX) spectroscopy, dynamic light scattering (DLS) measurements, zeta potential, zeta deviation analysis and UV-visible (UV-Vis) spectroscopic studies. PMID:25650352

  9. Long open path Fourier transform spectroscopy measurements of greenhouse gases in the near infrared

    NASA Astrophysics Data System (ADS)

    Griffith, David; Pöhler, Denis; Schmidt, Stefan; Hammer, Samuel; Vardag, Sanam; Levin, Ingeborg; Platt, Ulrich

    2015-04-01

    Atmospheric composition measurements are an important tool to quantify local and regional emissions and sinks of greenhouse gases. But how representative are in situ measurements at one point in an inhomogeneous environment? Open path Fourier Transform Spectroscopy (FTS) measurements potentially offer spatial averaging and continuous measurements of several trace gases (including CO2, CH4, CO and N2O) simultaneously in the same airmass. Spatial averaging over kilometre scales is a better fit to the finest scale atmospheric models becoming available, and helps bridge the gap between models and in situ measurements. With what precision, accuracy and reliability can such measurements be made? Building on our pooled experience in ground-level open path Fourier transform spectroscopy and TCCON solar FTS in the infrared (Wollongong) and long path DOAS techniques in the UV-visible (Heidelberg), we set up a new type of open path measurement system across a 1.5 km one-way path in urban Heidelberg, Germany, using FTS in the near infrared. Direct open-atmosphere measurements of trace gases CO2, CH4, CO and N2O as well as O2 were retrieved from several absorption bands between 4000 and 8000 cm-1 (2.5 - 1.25 micron). At one end of the path an in situ FTIR analyser simultaneously collected well calibrated measurements of the same species for comparison with the open path-integrated measurements. The measurements ran continuously from June - November 2014. We introduce the open path FTS measurement system and present an analysis of the results, including assessment of precision, accuracy relative to co-incident in situ measurements, reliability, and avenues for further improvements and extensions. Short term precision of the open path measurement of CO2 was better than 1 ppm for 5 minute averages and thus sufficient for studies in urban and other non-background environments. Measurement bias relative to calibrated in situ measurements was stable across the measurement period. The system operated reliably with data losses mainly due only to weather events such as rain and fog preventing transmission of the IR beam. In principle the system can be improved to provide longer pathlengths and higher precision.

  10. Investigation of the photochemistry of the poly{l_brace}p-phenylenevinylene{r_brace} precursor system: Implications for nanolithography

    SciTech Connect

    Cotton, D. V.; Fell, C. J.; Belcher, W. J.; Dastoor, P. C.

    2007-05-07

    The photochemistry of poly{l_brace}p-phenylene[1-(tetrahydrothiophen-1-io)ethylene chloride]{r_brace} (PPTEC), a water soluble precursor of the semiconducting polymer, poly{l_brace}p-phenylenevinylene{r_brace} (PPV), has been studied both under atmospheric conditions and in environments devoid of oxygen. UV-visible spectroscopy and photoluminescence data has been used to provide a picture of the mechanistic pathways involved in UV irradiation of the PPTEC material. A new quantitative model for the effect of UV irradiation upon film morphology is presented, which leads to insights for the improved control of the characteristics of PPV nanostructures produced via near-field scanning optical lithography.

  11. Quantitative ultrasound molecular imaging.

    PubMed

    Yeh, James Shue-Min; Sennoga, Charles A; McConnell, Ellen; Eckersley, Robert; Tang, Meng-Xing; Nourshargh, Sussan; Seddon, John M; Haskard, Dorian O; Nihoyannopoulos, Petros

    2015-09-01

    Ultrasound molecular imaging using targeting microbubbles is predominantly a semi-quantitative tool, thus limiting its potential diagnostic power and clinical applications. In the work described here, we developed a novel method for acoustic quantification of molecular expression. E-Selectin expression in the mouse heart was induced by lipopolysaccharide. Real-time ultrasound imaging of E-selectin expression in the heart was performed using E-selectin-targeting microbubbles and a clinical ultrasound scanner in contrast pulse sequencing mode at 14 MHz, with a mechanical index of 0.22-0.26. The level of E-selectin expression was quantified using a novel time-signal intensity curve analytical method based on bubble elimination, which consisted of curve-fitting the bi-exponential equation [Formula: see text] to the elimination phase of the myocardial time-signal intensity curve. Ar and Af represent the maximum signal intensities of the retained and freely circulating bubbles in the myocardium, respectively; ?r and ?f represent the elimination rate constants of the retained and freely circulating bubbles in the myocardium, respectively. Ar correlated strongly with the level of E-selectin expression (|r|>0.8), determined using reverse transcriptase real-time quantitative polymerase chain reaction, and the duration of post-lipopolysaccharide treatment-both linearly related to cell surface E-selectin protein (actual bubble target) concentration in the expression range imaged. Compared with a conventional acoustic quantification method (which used retained bubble signal intensity at 20 min post-bubble injection), this new approach exhibited greater dynamic range and sensitivity and was able to simultaneously quantify other useful characteristics (e.g., the microbubble half-life). In conclusion, quantitative determination of the level of molecular expression is feasible acoustically using a time-signal intensity curve analytical method based on bubble elimination. PMID:26044707

  12. Quantitative evaluation of defect-models in superconducting phase qubits

    E-print Network

    J. H. Cole; C. Müller; P. Bushev; G. J. Grabovskij; J. Lisenfeld; A. Lukashenko; A. V. Ustinov; A. Shnirman

    2010-10-28

    We use high-precision spectroscopy and detailed theoretical modelling to determine the form of the coupling between a superconducting phase qubit and a two-level defect. Fitting the experimental data with our theoretical model allows us to determine all relevant system parameters. A strong qubit-defect coupling is observed, with a nearly vanishing longitudinal component. Using these estimates, we quantitatively compare several existing theoretical models for the microscopic origin of two-level defects.

  13. Quantitative evaluation of defect-models in superconducting phase qubits

    E-print Network

    Cole, J H; Bushev, P; Grabovskij, G J; Lisenfeld, J; Lukashenko, A; Ustinov, A V; Shnirman, A

    2010-01-01

    We use high-precision spectroscopy and detailed theoretical modelling to determine the form of the coupling between a superconducting phase qubit and a two-level defect. Fitting the experimental data with our theoretical model allows us to determine all relevant system parameters. A strong qubit-defect coupling is observed, with a nearly vanishing longitudinal component. Using these estimates, we quantitatively compare several existing theoretical models for the microscopic origin of two-level defects.

  14. Fourier Transform Infrared Spectroscopy

    E-print Network

    Nizkorodov, Sergey

    FTIR - 1 Fourier Transform Infrared Spectroscopy FTIR DETERMINATION OF MTBE IN GASOLINE AND ETHANOL IN VODKA AND MOUTHWASH Last updated: June 17, 2014 #12;FTIR - 2 Fourier Transform Infrared Spectroscopy

  15. Heterodyne laser spectroscopy system

    DOEpatents

    Wyeth, Richard W. (Livermore, CA); Paisner, Jeffrey A. (San Ramon, CA); Story, Thomas (Antioch, CA)

    1989-01-01

    A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency and the like, and provides spectral analysis of a laser beam.

  16. Heterodyne laser spectroscopy system

    DOEpatents

    Wyeth, Richard W. (Livermore, CA); Paisner, Jeffrey A. (San Ramon, CA); Story, Thomas (Antioch, CA)

    1990-01-01

    A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency, and provides spectral analysis of a laser beam.

  17. Drug analysis by Raman and micro-Raman spectroscopy.

    PubMed

    Huong, P V

    1986-01-01

    The technique of Raman spectroscopy, resonance Raman spectroscopy and micro-Raman spectroscopy is described for application to drug analysis and investigation. Possibilities and limits are mentioned for qualitative and quantitative analyses as well as for studies of structure and interactions. Some principal interaction modes, such as hydrogen bonding, proton transfer, charge transfer and ion-molecule attraction, are shown to explain drug reactivity. Illustrations are given based on several drug families, in particular vitamins, anti-depressants, cardio-active and anticancer drugs. PMID:16867562

  18. Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions

    SciTech Connect

    Bradforth, S.E.

    1992-11-01

    The transition state region of a neutral bimolecular reaction may be experimentally investigated by photoelectron spectroscopy of an appropriate negative ion. The photoelectron spectrum provides information on the spectroscopy and dynamics of the short lived transition state and may be used to develop model potential energy surfaces that are semi-quantitative in this important region. The principles of bound [yields] bound negative ion photoelectron spectroscopy are illustrated by way of an example: a full analysis of the photoelectron bands of CN[sup [minus

  19. Quantitative chemical imaging with multiplex stimulated Raman scattering microscopy.

    PubMed

    Fu, Dan; Lu, Fa-Ke; Zhang, Xu; Freudiger, Christian; Pernik, Douglas R; Holtom, Gary; Xie, Xiaoliang Sunney

    2012-02-29

    Stimulated Raman scattering (SRS) microscopy is a newly developed label-free chemical imaging technique that overcomes the speed limitation of confocal Raman microscopy while avoiding the nonresonant background problem of coherent anti-Stokes Raman scattering (CARS) microscopy. Previous demonstrations have been limited to single Raman band measurements. We present a novel modulation multiplexing approach that allows real-time detection of multiple species using the fast Fourier transform. We demonstrate the quantitative determination of chemical concentrations in a ternary mixture. Furthermore, two imaging applications are pursued: (1) quantitative determination of oil content as well as pigment and protein concentration in microalgae cultures; and (2) 3D high-resolution imaging of blood, lipids, and protein distribution in ex vivo mouse skin tissue. We believe that quantitative multiplex SRS uniquely combines the advantage of fast label-free imaging with the fingerprinting capability of Raman spectroscopy and enables numerous applications in lipid biology as well as biomedical imaging. PMID:22316340

  20. Quantitative metamaterial property extraction

    E-print Network

    Schurig, David

    2015-01-01

    We examine an extraction model for metamaterials, not previously reported, that gives precise, quantitative and causal representation of S parameter data over a broad frequency range, up to frequencies where the free space wavelength is only a modest factor larger than the unit cell dimension. The model is comprised of superposed, slab shaped response regions of finite thickness, one for each observed resonance. The resonance dispersion is Lorentzian and thus strictly causal. This new model is compared with previous models for correctness likelihood, including an appropriate Occam's factor for each fit parameter. We find that this new model is by far the most likely to be correct in a Bayesian analysis of model fits to S parameter simulation data for several classic metamaterial unit cells.

  1. Surface inspection using FTIR spectroscopy

    NASA Technical Reports Server (NTRS)

    Powell, G. L.; Smyrl, N. R.; Williams, D. M.; Meyers, H. M., III; Barber, T. E.; Marrero-Rivera, M.

    1995-01-01

    The use of reflectance Fourier transform infrared (FTIR) spectroscopy as a tool for surface inspection is described. Laboratory instruments and portable instruments can support remote sensing probes that can map chemical contaminants on surfaces with detection limits under the best of conditions in the sub-nanometer range, i.e.. near absolute cleanliness, excellent performance in the sub-micrometer range, and useful performance for films tens of microns thick. Examples of discovering and quantifying contamination such as mineral oils and greases, vegetable oils, and silicone oils on aluminum foil, galvanized sheet steel, smooth aluminum tubing, and sandblasted 7075 aluminum alloy and D6AC steel. The ability to map in time and space the distribution of oil stains on metals is demonstrated. Techniques associated with quantitatively applying oils to metals, subsequently verifying the application, and non-linear relationships between reflectance and the quantity oil are described.

  2. Probing zeolites by vibrational spectroscopies.

    PubMed

    Bordiga, Silvia; Lamberti, Carlo; Bonino, Francesca; Travert, Arnaud; Thibault-Starzyk, Frédéric

    2015-10-21

    This review addresses the most relevant aspects of vibrational spectroscopies (IR, Raman and INS) applied to zeolites and zeotype materials. Surface Brønsted and Lewis acidity and surface basicity are treated in detail. The role of probe molecules and the relevance of tuning both the proton affinity and the steric hindrance of the probe to fully understand and map the complex site population present inside microporous materials are critically discussed. A detailed description of the methods needed to precisely determine the IR absorption coefficients is given, making IR a quantitative technique. The thermodynamic parameters of the adsorption process that can be extracted from a variable-temperature IR study are described. Finally, cutting-edge space- and time-resolved experiments are reviewed. All aspects are discussed by reporting relevant examples. When available, the theoretical literature related to the reviewed experimental results is reported to support the interpretation of the vibrational spectra on an atomic level. PMID:26435467

  3. Field spectroscopy of agricultural crops

    NASA Technical Reports Server (NTRS)

    Bauer, M. E.; Daughtry, C. S. T.; Biehl, L. L.; Kanemasu, E. T.; Hall, F. G.

    1986-01-01

    The development of the full potential of multispectral data acquired from satellites, requires quantitative knowledge, and physical models of the spectral properties of specific earth surface features. Knowledge of the relationships between spectral-radiometric characteristics and important biophysical parameters of agricultural crops and soils can best be obtained by carefully controlled studies of fields or plots. It is important to select plots where data describing the agronomic-biophysical properties of the crop canopies and soil background are attainable, taking into account also the feasibility of frequent timely calibrated spectral measurements. The term 'field spectroscopy' is employed for this research. The present paper is concerned with field research which was sponsored by NASA as part of the AgRISTARS Supporting Research Project. Attention is given to field research objectives, field research instrumentation, measurement procedures, spectral-temporal profile modeling, and the effects of cultural and environmental factors on crop reflectance.

  4. Quantitative fMRI and oxidative neuroenergetics.

    PubMed

    Hyder, Fahmeed; Rothman, Douglas L

    2012-08-15

    The discovery of functional magnetic resonance imaging (fMRI) has greatly impacted neuroscience. The blood oxygenation level-dependent (BOLD) signal, using deoxyhemoglobin as an endogenous paramagnetic contrast agent, exposes regions of interest in task-based and resting-state paradigms. However the BOLD contrast is at best a partial measure of neuronal activity, because the functional maps obtained by differencing or correlations ignore the total neuronal activity in the baseline state. Here we describe how studies of brain energy metabolism at Yale, especially with (13)C magnetic resonance spectroscopy and related techniques, contributed to development of quantitative functional brain imaging with fMRI by providing a reliable measurement of baseline energy. This narrative takes us on a journey, from molecules to mind, with illuminating insights about neuronal-glial activities in relation to energy demand of synaptic activity. These results, along with key contributions from laboratories worldwide, comprise the energetic basis for quantitative interpretation of fMRI data. PMID:22542993

  5. Quantitative Species Measurements In Microgravity Combustion Flames

    NASA Technical Reports Server (NTRS)

    Chen, Shin-Juh; Pilgrim, Jeffrey S.; Silver, Joel A.; Piltch, Nancy D.

    2003-01-01

    The capability of models and theories to accurately predict and describe the behavior of low gravity flames can only be verified by quantitative measurements. Although video imaging, simple temperature measurements, and velocimetry methods have provided useful information in many cases, there is still a need for quantitative species measurements. Over the past decade, we have been developing high sensitivity optical absorption techniques to permit in situ, non-intrusive, absolute concentration measurements for both major and minor flames species using diode lasers. This work has helped to establish wavelength modulation spectroscopy (WMS) as an important method for species detection within the restrictions of microgravity-based measurements. More recently, in collaboration with Prof. Dahm at the University of Michigan, a new methodology combining computed flame libraries with a single experimental measurement has allowed us to determine the concentration profiles for all species in a flame. This method, termed ITAC (Iterative Temperature with Assumed Chemistry) was demonstrated for a simple laminar nonpremixed methane-air flame at both 1-g and at 0-g in a vortex ring flame. In this paper, we report additional normal and microgravity experiments which further confirm the usefulness of this approach. We also present the development of a new type of laser. This is an external cavity diode laser (ECDL) which has the unique capability of high frequency modulation as well as a very wide tuning range. This will permit the detection of multiple species with one laser while using WMS detection.

  6. Quantitative imaging of turbulent and reacting flows

    SciTech Connect

    Paul, P.H.

    1993-12-01

    Quantitative digital imaging, using planar laser light scattering techniques is being developed for the analysis of turbulent and reacting flows. Quantitative image data, implying both a direct relation to flowfield variables as well as sufficient signal and spatial dynamic range, can be readily processed to yield two-dimensional distributions of flowfield scalars and in turn two-dimensional images of gradients and turbulence scales. Much of the development of imaging techniques to date has concentrated on understanding the requisite molecular spectroscopy and collision dynamics to be able to determine how flowfield variable information is encoded into the measured signal. From this standpoint the image is seen as a collection of single point measurements. The present effort aims at realizing necessary improvements in signal and spatial dynamic range, signal-to-noise ratio and spatial resolution in the imaging system as well as developing excitation/detection strategies which provide for a quantitative measure of particular flowfield scalars. The standard camera used for the study is an intensified CCD array operated in a conventional video format. The design of the system was based on detailed modeling of signal and image transfer properties of fast UV imaging lenses, image intensifiers and CCD detector arrays. While this system is suitable for direct scalar imaging, derived quantities (e.g. temperature or velocity images) require an exceptionally wide dynamic range imaging detector. To apply these diagnostics to reacting flows also requires a very fast shuttered camera. The authors have developed and successfully tested a new type of gated low-light level detector. This system relies on fast switching of proximity focused image-diode which is direct fiber-optic coupled to a cooled CCD array. Tests on this new detector show significant improvements in detection limit, dynamic range and spatial resolution as compared to microchannel plate intensified arrays.

  7. Quantitative environmental risk analysis

    SciTech Connect

    Klovning, J.; Nilsen, E.F.

    1995-12-31

    According to regulations relating to implementation and rise of risk analysis in the petroleum activities issued by the Norwegian Petroleum Directorate, it is mandatory for an operator on the Norwegian Continental Shelf to establish acceptance criteria for environmental risk in the activities and carry out environmental risk analysis. This paper presents a {open_quotes}new{close_quotes} method for environmental risk analysis developed by the company. The objective has been to assist the company to meet rules and regulations and to assess and describe the environmental risk in a systematic manner. In the environmental risk analysis the most sensitive biological resource in the affected area is used to assess the environmental damage. The analytical method is based on the methodology for quantitative risk analysis related to loss of life. In addition it incorporates the effect of seasonal fluctuations in the environmental risk evaluations. The paper is describing the function of the main analytical sequences exemplified through an analysis of environmental risk related to exploration drilling in an environmental sensitive area on the Norwegian Continental Shelf.

  8. Quantitive DNA Fiber Mapping

    SciTech Connect

    Lu, Chun-Mei; Wang, Mei; Greulich-Bode, Karin M.; Weier, Jingly F.; Weier, Heinz-Ulli G.

    2008-01-28

    Several hybridization-based methods used to delineate single copy or repeated DNA sequences in larger genomic intervals take advantage of the increased resolution and sensitivity of free chromatin, i.e., chromatin released from interphase cell nuclei. Quantitative DNA fiber mapping (QDFM) differs from the majority of these methods in that it applies FISH to purified, clonal DNA molecules which have been bound with at least one end to a solid substrate. The DNA molecules are then stretched by the action of a receding meniscus at the water-air interface resulting in DNA molecules stretched homogeneously to about 2.3 kb/{micro}m. When non-isotopically, multicolor-labeled probes are hybridized to these stretched DNA fibers, their respective binding sites are visualized in the fluorescence microscope, their relative distance can be measured and converted into kilobase pairs (kb). The QDFM technique has found useful applications ranging from the detection and delineation of deletions or overlap between linked clones to the construction of high-resolution physical maps to studies of stalled DNA replication and transcription.

  9. Synthesis, Structure and Spectroscopy Study of a 1D Copper Coordination Polymer Based on a Carboxybenzyl Viologen Ligand and SCN-Anion.

    PubMed

    Qiu, Li-xia; Wan, Fang; Zhu, Bin-bin; Sun, Yan-qiong; You, Yi; Chen, Yi-ping

    2015-05-01

    A zwitterionic viologen derivative ligand, 1,1'-bis(4-carboxybenzyl)-4 4'-bipyridinium dichloride (H2BpybcCl2) as a multifunctional ligand, has been synthesized incorporating a 4,4'-bipyridine core with two carboxylate groups as a. building block, specifically designed for the rational construction of metal-organic frameworks. H2BpybcCl2 ligand is a multifunctional ligand that contains viologen's specific functions and carboxylate coordination groups. The coordination polymers of viologen carboxylate with copper thiocyanate are not reported to date. A novel copper coordination polymer, [Cu(SCN)2 (Bpybc)] (I) was by solution diffusion method and characterized by single-crystal X-ray diffraction, XRD, elemental analyses, IR spectroscopy, UV-Vis DRS, TG analysis and liquid-state luminescent properties. Compound I crystallized in the monoclinic system with C2/c space group. Crystal data for complex I is as follow: a=19. 508(4) A, b=9. 474(2) Å, c =16. 963(3) Å, ?=90°, ?=124. 92(3)°, ?=90°. Two SCN-anions were coordinated to the Cu2+ cation forming a [Cu(SCN)2] unit. Complex I was built up by [Cu(SCN)2] units bridged sequentially by ladder-shaped Bpybc ligands to form one-dimensional zigzag chains running along the [203] direction. The chains were held together by ?-? interaction between the pyridine rings and phenyl rings, thus yielding a 3-D extended supramolecular network. The UV-Visible absorption spectra show the absorption bands of ?-?* transitions of Bpybc ligands and d-->d transition of Cu2+. The liquid-state luminescent property of compound I was investigated at room temperature. Attractively, the complex exhibits strong blue emission peak at 533 nm (?Ex=360 nn) that can be assigned to intraligand transition of Bpybc ligand when it was excited at 360 nm. PMID:26415457

  10. Synthesis and properties of novel fullerene derivatives

    SciTech Connect

    Da Ros, T.; Prato, M.; Guldi, D.; Alessio, E.; Valli, L.; Carano, M.; Paolucci, F.; Ceroni, P.; Roffia, S.

    1998-08-01

    Synthesis and chemical properties of a novel fullerene-porphyrin dyad is reported. Energy/electron transfer is studied based on cyclic voltametry and UV-visible spectroscopy. {copyright} {ital 1998 American Institute of Physics.}

  11. Characterising nutrient-induced fluorescence transients (NIFTs) in nitrogen-stressed Chlorella emersonii (Chlorophyta)

    E-print Network

    McCarthy, T.K.

    of techniques including NIFTs, conventional pigment analysis using UV/Visible spectrophotometry and Fourier transform infrared (FT-IR) and Raman spectroscopy. Results showed that the addition of NH4 + and NO3 2

  12. Proton magnetic resonance spectroscopy in multiple sclerosis

    SciTech Connect

    Wolinsky, J.S.; Narayana, P.A.; Fenstermacher, M.J. )

    1990-11-01

    Regional in vivo proton magnetic resonance spectroscopy provides quantitative data on selected chemical constituents of brain. We imaged 16 volunteers with clinically definite multiple sclerosis on a 1.5 tesla magnetic resonance scanner to define plaque-containing volumes of interest, and obtained localized water-suppressed proton spectra using a stimulated echo sequence. Twenty-five of 40 plaque-containing regions provided spectra of adequate quality. Of these, 8 spectra from 6 subjects were consistent with the presence of cholesterol or fatty acids; the remainder were similar to those obtained from white matter of normal volunteers. This early experience with regional proton spectroscopy suggests that individual plaques are distinct. These differences likely reflect dynamic stages of the evolution of the demyelinative process not previously accessible to in vivo investigation.

  13. BATSE spectroscopy analysis system

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.; Bansal, Sandhia; Basu, Anju; Brisco, Phil; Cline, Thomas L.; Friend, Elliott; Laubenthal, Nancy; Panduranga, E. S.; Parkar, Nuru; Rust, Brad

    1992-01-01

    The Burst and Transient Source Experiment (BATSE) Spectroscopy Analysis System (BSAS) is the software system which is the primary tool for the analysis of spectral data from BATSE. As such, Guest Investigators and the community as a whole need to know its basic properties and characteristics. Described here are the characteristics of the BATSE spectroscopy detectors and the BSAS.

  14. FEATURE ARTICLE Terahertz Spectroscopy

    E-print Network

    -resolved THz spectroscopy", are that it implies generation and detection of THz pulses in a synchronous could be generated, propagated through free space, and subsequently detected in the time-domain. Since spectroscopy grew out of efforts to generate and detect ultrashort electrical transients as they propagated

  15. A Signature of Roaming Dynamics in the Thermal Decomposition of Ethyl Nitrite: Chirped-Pulse Rotational Spectroscopy and Kinetic Modeling

    E-print Network

    Prozument, Kirill

    Chirped-pulse (CP) Fourier transform rotational spectroscopy is uniquely suited for near-universal quantitative detection and structural characterization of mixtures that contain multiple molecular and radical species. In ...

  16. Quantitative Genetics, House Sparrows and a Multivariate

    E-print Network

    Steinsland, Ingelin

    NTNU Quantitative Genetics, House Sparrows and a Multivariate Gaussian Markov Random Field Model Quantitative Genetics, House Sparrows and a Multivariate Gaussian Markov Random Field Model ­ p.1/25 #12;NTNU Quantitative Genetics Quantitative genetics is the study of quantitative characters. It is based

  17. Quantitative Portraits of Lexical Elements Kyo Kageura

    E-print Network

    Quantitative Portraits of Lexical Elements Kyo Kageura Human and Social Information Research quantitative "weighting" of lexical elements are defined, and then draws, quantitative portraits of a few by drawing quantitative portraits of some lexical items using the quantitative measures. 2 Texts and lexica

  18. News Note: Quantitative Imaging Program

    Cancer.gov

    NCI is launching a new program to qualify existing NCI designated Cancer Centers with an added attribute -- as Centers of Quantitative Imaging Excellence. This program will significantly decrease potential variability in image procedures done while a pati

  19. Quantitative analysis of masculinity perceptions 

    E-print Network

    Cima, Brian Norman

    2002-01-01

    This study was conducted using a modified version of the Brannon's Masculinity index, designed to measure quantitatively the ideologies of American masculinity. Included is an extensive literature review and an explanation ...

  20. Quantitative linear and nonlinear resonant inspection techniques for characterizing thermal damage in

    E-print Network

    the resonant frequency one can evaluate the elastic properties (E). Based on this simple principle, but adapted]. Resonant Ultrasound Spectroscopy (RUS) allows the material elastic properties to be determined accurately period of time. This paper aims at providing some quantitative information related to the degree of micro

  1. Quantitative photoacoustic imaging in radiative transport regime

    E-print Network

    Ren, Kui

    Quantitative photoacoustic imaging in radiative transport regime Alexander V. Mamonov Kui Ren July 6, 2012 Abstract The objective of quantitative photoacoustic tomography (QPAT) is to reconstruct. Key words. Quantitative photoacoustic tomography (QPAT), sectional photoacoustic tomogra- phy

  2. Detection of propofol concentrations in blood by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Wróbel, M. S.; Gnyba, M.; Urnia?, R.; Myllylä, T. S.; Jedrzejewska-Szczerska, M.

    2015-07-01

    In this paper we present a proof-of-concept of a Raman spectroscopy-based approach for measuring the content of propofol, a common anesthesia drug, in whole human blood, and plasma, which is intended for use during clinical procedures. This method utilizes the Raman spectroscopy as a chemically-sensitive method for qualitative detection of the presence of a drug and a quantitative determination of its concentration. A number of samples from different patients with added various concentrations of propofol IV solution were measured. This is most equivalent to a real in-vivo situation. Subsequent analysis of a set of spectra was carried out to extract qualitative and quantitative information. We conclude, that the changes in the spectra of blood with propofol, overlap with the most prominent lines of the propofol solution, especially at spectral regions: 1450 cm-1, 1250- 1260 cm-1, 1050 cm-1, 875-910 cm-1, 640 cm-1. Later, we have introduced a quantitative analysis program based on correlation matrix closest fit, and a LOO cross-validation. We have achieved 36.67% and 60% model precision when considering full spectra, or specified bands, respectively. These results prove the possibility of using Raman spectroscopy for quantitative detection of propofol concentrations in whole human blood.

  3. Developing Geoscience Students' Quantitative Skills

    NASA Astrophysics Data System (ADS)

    Manduca, C. A.; Hancock, G. S.

    2005-12-01

    Sophisticated quantitative skills are an essential tool for the professional geoscientist. While students learn many of these sophisticated skills in graduate school, it is increasingly important that they have a strong grounding in quantitative geoscience as undergraduates. Faculty have developed many strong approaches to teaching these skills in a wide variety of geoscience courses. A workshop in June 2005 brought together eight faculty teaching surface processes and climate change to discuss and refine activities they use and to publish them on the Teaching Quantitative Skills in the Geosciences website (serc.Carleton.edu/quantskills) for broader use. Workshop participants in consultation with two mathematics faculty who have expertise in math education developed six review criteria to guide discussion: 1) Are the quantitative and geologic goals central and important? (e.g. problem solving, mastery of important skill, modeling, relating theory to observation); 2) Does the activity lead to better problem solving? 3) Are the quantitative skills integrated with geoscience concepts in a way that makes sense for the learning environment and supports learning both quantitative skills and geoscience? 4) Does the methodology support learning? (e.g. motivate and engage students; use multiple representations, incorporate reflection, discussion and synthesis) 5) Are the materials complete and helpful to students? 6) How well has the activity worked when used? Workshop participants found that reviewing each others activities was very productive because they thought about new ways to teach and the experience of reviewing helped them think about their own activity from a different point of view. The review criteria focused their thinking about the activity and would be equally helpful in the design of a new activity. We invite a broad international discussion of the criteria(serc.Carleton.edu/quantskills/workshop05/review.html).The Teaching activities can be found on the Teaching Quantitative Skills in the Geosciences website (serc.Carleton.edu/quantskills/). In addition to the teaching activity collection (85 activites), this site contains a variety of resources to assist faculty with the methods they use to teach quantitative skills at both the introductory and advanced levels; information about broader efforts in quantitative literacy involving other science disciplines, and a special section of resources for students who are struggling with their quantitative skills. The site is part of the Digital Library for Earth Science Education and has been developed by geoscience faculty in collaboration with mathematicians and mathematics educators with funding from the National Science Foundation.

  4. Quantitative multiplexing with nano-self-assemblies in SERS.

    PubMed

    Kasera, Setu; Herrmann, Lars O; del Barrio, Jesús; Baumberg, Jeremy J; Scherman, Oren A

    2014-01-01

    Multiplexed or simultaneous detection of multiple analytes is a valuable tool in many analytical applications. However, complications caused by the presence of interfering compounds in a sample form a major drawback in existing molecular sensor technologies, particularly in multi-analyte systems. Although separating analytes through extraction or chromatography can partially address the problem of interferents, there remains a need for developing direct observational tools capable of multiplexing that can be applied in situ. Surface-enhanced Raman Spectroscopy (SERS) is an optical molecular finger-printing technique that has the ability to resolve analytes from within mixtures. SERS has attracted much attention for its potential in multiplexed sensing but it has been limited in its quantitative abilities. Here, we report a facile supramolecular SERS-based method for quantitative multiplex analysis of small organic molecules in aqueous environments such as human urine. PMID:25354650

  5. Quantitative multiplexing with nano-self-assemblies in SERS

    PubMed Central

    Kasera, Setu; Herrmann, Lars O.; Barrio, Jesús del; Baumberg, Jeremy J.; Scherman, Oren A.

    2014-01-01

    Multiplexed or simultaneous detection of multiple analytes is a valuable tool in many analytical applications. However, complications caused by the presence of interfering compounds in a sample form a major drawback in existing molecular sensor technologies, particularly in multi-analyte systems. Although separating analytes through extraction or chromatography can partially address the problem of interferents, there remains a need for developing direct observational tools capable of multiplexing that can be applied in situ. Surface-enhanced Raman Spectroscopy (SERS) is an optical molecular finger-printing technique that has the ability to resolve analytes from within mixtures. SERS has attracted much attention for its potential in multiplexed sensing but it has been limited in its quantitative abilities. Here, we report a facile supramolecular SERS-based method for quantitative multiplex analysis of small organic molecules in aqueous environments such as human urine. PMID:25354650

  6. Quantitative methods for analyzing cell-cell adhesion in development.

    PubMed

    Kashef, Jubin; Franz, Clemens M

    2015-05-01

    During development cell-cell adhesion is not only crucial to maintain tissue morphogenesis and homeostasis, it also activates signalling pathways important for the regulation of different cellular processes including cell survival, gene expression, collective cell migration and differentiation. Importantly, gene mutations of adhesion receptors can cause developmental disorders and different diseases. Quantitative methods to measure cell adhesion are therefore necessary to understand how cells regulate cell-cell adhesion during development and how aberrations in cell-cell adhesion contribute to disease. Different in vitro adhesion assays have been developed in the past, but not all of them are suitable to study developmentally-related cell-cell adhesion processes, which usually requires working with low numbers of primary cells. In this review, we provide an overview of different in vitro techniques to study cell-cell adhesion during development, including a semi-quantitative cell flipping assay, and quantitative single-cell methods based on atomic force microscopy (AFM)-based single-cell force spectroscopy (SCFS) or dual micropipette aspiration (DPA). Furthermore, we review applications of Förster resonance energy transfer (FRET)-based molecular tension sensors to visualize intracellular mechanical forces acting on cell adhesion sites. Finally, we describe a recently introduced method to quantitate cell-generated forces directly in living tissues based on the deformation of oil microdroplets functionalized with adhesion receptor ligands. Together, these techniques provide a comprehensive toolbox to characterize different cell-cell adhesion phenomena during development. PMID:25448695

  7. Multidimensional high harmonic spectroscopy

    NASA Astrophysics Data System (ADS)

    Bruner, Barry D.; Soifer, Hadas; Shafir, Dror; Serbinenko, Valeria; Smirnova, Olga; Dudovich, Nirit

    2015-09-01

    High harmonic generation (HHG) has opened up a new frontier in ultrafast science where attosecond time resolution and Angstrom spatial resolution are accessible in a single measurement. However, reconstructing the dynamics under study is limited by the multiple degrees of freedom involved in strong field interactions. In this paper we describe a new class of measurement schemes for resolving attosecond dynamics, integrating perturbative nonlinear optics with strong-field physics. These approaches serve as a basis for multidimensional high harmonic spectroscopy. Specifically, we show that multidimensional high harmonic spectroscopy can measure tunnel ionization dynamics with high precision, and resolves the interference between multiple ionization channels. In addition, we show how multidimensional HHG can function as a type of lock-in amplifier measurement. Similar to multi-dimensional approaches in nonlinear optical spectroscopy that have resolved correlated femtosecond dynamics, multi-dimensional high harmonic spectroscopy reveals the underlying complex dynamics behind attosecond scale phenomena.

  8. Charmonium spectroscopy, 1987

    SciTech Connect

    Cahn, R.N.

    1987-07-30

    The state of charmonium spectroscopy is reviewed. All analyses proceed from a spin-dependent, non-relativistic Schroedinger equation. Many of the possible branching ratios for charm like states are investigated. 17 refs.

  9. Spectroscopy - so what?

    NASA Astrophysics Data System (ADS)

    Stanley, Matthew

    2010-07-01

    The development of astronomical spectroscopy allowed amazing achievements in investigating the composition and motion of celestial bodies. But even beyond specific measurements and results, the fruitfulness and practice of spectroscopy had important ramifications on a more abstract level. This paper will discuss ways in which spectroscopy inspired or boosted new theories of the atom, life, and the Universe; redrew the boundaries among scientific disciplines; demonstrated the unity of terrestrial and celestial physical laws; changed what counted as scientific knowledge; and even revealed divine mysteries. Scientists and science writers from the first half-century of astronomical spectroscopy will be discussed, including James Clerk Maxwell, William Crookes, John Tyndall, Agnes Clerke, William Huggins and Norman Lockyer.

  10. Spectroscopy - so what?

    NASA Astrophysics Data System (ADS)

    Stanley, Matthew

    2010-01-01

    The development of astronomical spectroscopy allowed amazing achievements in investigating the composition and motion of celestial bodies. But even beyond specific measurements and results, the fruitfulness and practice of spectroscopy had important ramifications on a more abstract level. This paper will discuss ways in which spectroscopy inspired or boosted new theories of the atom, life, and the universe; redrew the boundaries among scientific disciplines; demonstrated the unity of terrestrial and celestial physical laws; changed what counted as scientific knowledge; and even revealed divine mysteries. Scientists and science writers from the first half-century of astronomical spectroscopy will be discussed, including James Clerk Maxwell, William Thomson (Lord Kelvin), John Tyndall, Agnes Clerke, William Huggins, and Norman Lockyer.

  11. Toward pure electronic spectroscopy

    E-print Network

    Petrovi?, Vladimir, 1978-

    2009-01-01

    In this thesis is summarized the progress toward completing our understanding of the Rydberg system of CaF and developing Pure Electronic Spectroscopy. The Rydberg system of CaF possesses a paradigmatic character due to ...

  12. Overtone spectroscopy in N{sub 2}O

    SciTech Connect

    Campargue, A.; Permogorov, D.; Bach, M.

    1995-12-31

    The near infrared and visible absorption spectrum of nitrous oxide {sup 14}N{sub 2}{sup 16}O has been recorded by Fourier Transform Absorption Spectroscopy, between 6500 and 11000 cm{sup -1}, and by Intracavity Laser Absorption Spectroscopy, between 11700 and 15000 cm{sup -1}. Fifteen new bands are observed and, altogether, thirty four cold and nine hot bands are rotationally analyzed. The related upper term values, vibrational assignments and principal rotational constants, as well as the relative band intensities will be quantitatively discussed in terms of the formation of vibrational clusters, on the basis of the effective Hamiltonian developed by Teffo and coworkers.

  13. Application of Fourier transform spectroscopy to air pollution problems

    NASA Astrophysics Data System (ADS)

    Shaw, J. H.; Calvert, J. G.

    1980-11-01

    The nature of information that can be retrieved from spectra obtained with Fourier transform spectroscopy is discussed. Nonlinear, least squares analysis of spectra is capable of retrieving information that is beyond the reach of conventional methods and has improved precision and accuracy. Fourier transform infrared spectroscopy was used to study quantitatively the kinetics and mechanisms of several chemical reactions that are of interest to atmospheric chemists and are important in the development of air pollution control strategies. The systems studied include the metastable, reactive, gaseous species, peroxynitric acid, hypochlorous acid, and dimethylnitrosamine.

  14. Electronic Spectroscopy & Dynamics

    SciTech Connect

    Mark Maroncelli, Nancy Ryan Gray

    2010-06-08

    The Gordon Research Conference (GRC) on Electronic Spectroscopy and Dynamics was held at Colby College, Waterville, NH from 07/19/2009 thru 07/24/2009. The Conference was well-attended with participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. The GRC on Electronic Spectroscopy & Dynamics showcases some of the most recent experimental and theoretical developments in electronic spectroscopy that probes the structure and dynamics of isolated molecules, molecules embedded in clusters and condensed phases, and bulk materials. Electronic spectroscopy is an important tool in many fields of research, and this GRC brings together experts having diverse backgrounds in physics, chemistry, biophysics, and materials science, making the meeting an excellent opportunity for the interdisciplinary exchange of ideas and techniques. Topics covered in this GRC include high-resolution spectroscopy, biological molecules in the gas phase, electronic structure theory for excited states, multi-chromophore and single-molecule spectroscopies, and excited state dynamics in chemical and biological systems.

  15. High fidelity nanohole enhanced Raman spectroscopy.

    SciTech Connect

    Bahns, J. T.; Guo, Q.; Gray, S. K.; Jaeger, H. M.; Chen, L.; Montgomery, J. M.; Univ. of Chicago

    2009-01-01

    Surface enhanced Raman spectroscopy (SERS) is a sensitive technique that can even detect single molecules. However, in many SERS applications, the strongly inhomogeneous distribution of intense local fields makes it very difficult for a quantitive assessment of the fidelity, or reproducibility of the signal, which limits the application of SERS. Herein, we report the development of exceptionally high-fidelity hole-enhanced Raman spectroscopy (HERS) from ordered, 2D hexagonal nanohole arrays. We take the fidelity f to be a measure of the percent deviation of the Raman peaks from measurement to measurement. Overall, area averaged fidelities for 12 gold array samples ranged from f {approx} 2-15% for HERS using aqueous R6G molecules. Furthermore, intensity modulations of the enhanced Raman spectra were measured for the first time as a function of polarization angle. The best of these measurements, which focus on static laser spots on the sample, could be consistent with even higher fidelities than the area-averaged results. Nanohole arrays in silver provided supporting polarization measurements and a more complete enhanced Raman fingerprint for phenylalanine molecules. We also carried out finite-difference time-domain calculations to assist in the interpretation of the experiments, identifying the polarization dependence as possibly arising from hole-hole interactions. Our results represent a step toward making quantitative and reproducible enhanced Raman measurements possible and also open new avenues for a large-scale source of highly uniform hot spots.

  16. Quantitative measurement of oxygen in microgravity combustion

    NASA Technical Reports Server (NTRS)

    Silver, Joel A.

    1995-01-01

    This research combines two innovations in an experimental system which should result in a new capability for quantitative, nonintrusive measurement of major combustion species. Using a newly available vertical cavity surface-emitting diode laser (VCSEL) and an improved spatial scanning method, we plan to measure the temporal and spatial profiles of the concentrations and temperatures of molecular oxygen in a candle flame and in a solid fuel (cellulose sheet) system. The required sensitivity for detecting oxygen is achieved by the use of high frequency wavelength modulation spectroscopy (WMS). Measurements will be performed in the NASA Lewis 2.2-second Drop Tower Facility. The objective of this research is twofold. First, we want to develop a better understanding of the relative roles of diffusion and reaction of oxygen in microgravity combustion. As the primary oxidizer species, oxygen plays a major role in controlling the observed properties of flames, including flame front speed (in solid or liquid flames), extinguishment characteristics, flame size, and flame temperature. The second objective is to develop better diagnostics based on diode laser absorption which can be of real value in microgravity combustion research. We will also demonstrate diode lasers' potential usefulness for compact, intrinsically-safe monitoring sensors aboard spacecraft. Such sensors could be used to monitor any of the major cabin gases as well as important pollutants.

  17. EDITORIAL: Nano Meets Spectroscopy Nano Meets Spectroscopy

    NASA Astrophysics Data System (ADS)

    Birch, David J. S.

    2012-08-01

    The multidisciplinary two-day Nano Meets Spectroscopy (NMS) event was held at the National Physical Laboratory (NPL), Teddington, UK, in September 2011. The event was planned from the outset to be at the interface of several areas—in particular, spectroscopy and nanoscience, and to bring together topics and people with different approaches to achieving common goals in biomolecular science. Hence the meeting cut across traditional boundaries and brought together researchers using diverse techniques, particularly fluorescence and Raman spectroscopy. Despite engaging common problems, these techniques are frequently seen as mutually exclusive with the two communities rarely interacting at conferences. The meeting was widely seen to have lived up to its billing in good measure. It attracted the maximum capacity of ~120 participants, including 22 distinguished speakers (9 from outside the UK), over 50 posters and a vibrant corporate exhibition comprising 10 leading instrument companies and IOP Publishing. The organizers were Professor David Birch (Chair), Dr Karen Faulds and Professor Duncan Graham of the University of Strathclyde, Professor Cait MacPhee of the University of Edinburgh and Dr Alex Knight of NPL. The event was sponsored by the European Science Foundation, the Institute of Physics, the Royal Society of Chemistry, NPL and the Scottish Universities Physics Alliance. The full programme and abstracts are available at http://sensor.phys.strath.ac.uk/nms/program.php. The programme was quite ambitious in terms of the breadth and depth of scope. The interdisciplinary and synergistic concept of 'X meets Y' played well, cross-fertilization between different fields often being a source of inspiration and progress. Fluorescence and Raman spectroscopy provided the core, but the meeting had little repetition and also attracted contributions on more specialist techniques such as CARS, super-resolution, single molecule and chiral methods. In terms of application the event bridged as far as medical application of nanotechnologies. It could have turned out that such a hotchpotch produced an incoherent event that lacked direction and focus, but in truth, as the feedback showed, the delegates revelled in the diversity and depth of quality. Excellent speakers, the common application to biomolecules and common language of spectroscopy were probably the reasons why things worked out so well. I am delighted to bring together in this special feature in Measurement Science and Technology a selection of contributions from the meeting and I thank all the authors for their excellent contributions. Included are papers on nanoparticles, plasmonics, sensing and imaging. This special feature, and indeed similar meetings in the future, will undoubtedly help sustain the 'nanomeeters' message of NMS.

  18. Rapid monitoring of benzylpenicillin sodium using Raman and surface enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Jiang, Xin; Qin, Xiaoyu; Yin, Di; Gong, Mengdi; Yang, Libin; Zhao, Bing; Ruan, Weidong

    2015-04-01

    At present, fluorescence spectroscopy, ultraviolet spectroscopy and infrared spectroscopy are usually used to detect drug molecules, however the information about using Raman spectroscopy to detect drug molecules is very few. In this work normal Raman spectroscopy and surface-enhanced Raman spectroscopy were utilized to study benzylpenicillin sodium (NaBP). The results show that NaBP is close to the surface of silver substrate through the carboxyl group, and the detection limit of NaBP is reduced to 1 × 10-7 mol/L. Accordingly, the quantitative analysis of NaBP can be carried out in the range of 1 × 10-4-1 × 10-7 mol/L concentration. And it is proved that NaBP is not stable in acid and alkali conditions and the decomposition reaction is very complex.

  19. Rapid analysis of wood using transient infrared spectroscopy and photoacoustic spectroscopy with PLS regression

    SciTech Connect

    Bajic, Stanley J.; Jones, Roger W.; McClelland, John F.; Meglen, Robert R.

    1998-06-01

    In the forest products industry, improved methods are needed for rapid analysis of wood and paper products. Currently, the best methods for determining chemical and physical properties of wood-based materials require considerable sample preparation and analysis time. Consequently, quantitative information is often not obtained on a time scale suitable for process monitoring, control, and quality assurance. The primary barriers to practical utilization of conventional infrared methods are the opaqueness and poor reflection properties of the wood-based materials. This paper demonstrates how photoacoustic and transient infrared spectroscopies have been combined with chemometric techniques to overcome the limitations of conventional infrared spectroscopies and to permit rapid chemical and physical characterization of wood chips. Both photoacoustic and transient infrared spectroscopic methods are examined as rapid at- and on-line techniques for feedstock identification and chemical composition analysis prior to processing. {copyright} {ital 1998 American Institute of Physics.}

  20. Towards quantitative assessment of calciphylaxis

    NASA Astrophysics Data System (ADS)

    Deserno, Thomas M.; Sárándi, István.; Jose, Abin; Haak, Daniel; Jonas, Stephan; Specht, Paula; Brandenburg, Vincent

    2014-03-01

    Calciphylaxis is a rare disease that has devastating conditions associated with high morbidity and mortality. Calciphylaxis is characterized by systemic medial calcification of the arteries yielding necrotic skin ulcerations. In this paper, we aim at supporting the installation of multi-center registries for calciphylaxis, which includes a photographic documentation of skin necrosis. However, photographs acquired in different centers under different conditions using different equipment and photographers cannot be compared quantitatively. For normalization, we use a simple color pad that is placed into the field of view, segmented from the image, and its color fields are analyzed. In total, 24 colors are printed on that scale. A least-squares approach is used to determine the affine color transform. Furthermore, the card allows scale normalization. We provide a case study for qualitative assessment. In addition, the method is evaluated quantitatively using 10 images of two sets of different captures of the same necrosis. The variability of quantitative measurements based on free hand photography is assessed regarding geometric and color distortions before and after our simple calibration procedure. Using automated image processing, the standard deviation of measurements is significantly reduced. The coefficients of variations yield 5-20% and 2-10% for geometry and color, respectively. Hence, quantitative assessment of calciphylaxis becomes practicable and will impact a better understanding of this rare but fatal disease.

  1. Book Reviews Quantitative Syntax Analysis

    E-print Network

    between QL and computational linguistics. Quantitative Syntax Analysis is a recent work on QL by Reinhard linguistics in general. © 2012 Association for Computational Linguistics In the first chapter, K¨ohler points when it comes to processing real texts. And that is why in computational linguistics, "devout executors

  2. Quantitative Research in Written Composition.

    ERIC Educational Resources Information Center

    Gebhard, Ann O.

    Offered as an introductory guide to teachers interested in approaching written English as a "second dialect" that students must master, this review covers quantitative investigations of written language. The first section deals with developmental studies, describing how a variety of researchers have related written structure to writer maturity.…

  3. Quantitative Risk Management Rudiger Frey

    E-print Network

    Frey, Rüdiger

    of specific challenges in credit risk management which are less relevant in market risk. · ScarcityLecture Quantitative Risk Management R¨udiger Frey Universit¨at Leipzig Wintersemester 2010 risk management C. Introduction to Portfolio Credit Derivatives c 2010 (Frey) 1 #12;A. Introduction

  4. Dielectric spectroscopy in agrophysics

    NASA Astrophysics Data System (ADS)

    Skierucha, W.; Wilczek, A.; Szyp?owska, A.

    2012-04-01

    The paper presents scientific foundation and some examples of agrophysical applications of dielectric spectroscopy techniques. The aim of agrophysics is to apply physical methods and techniques for studies of materials and processes which occur in agriculture. Dielectric spectroscopy, which describes the dielectric properties of a sample as a function of frequency, may be successfully used for examinations of properties of various materials. Possible test materials may include agrophysical objects such as soil, fruit, vegetables, intermediate and final products of the food industry, grain, oils, etc. Dielectric spectroscopy techniques enable non-destructive and non-invasive measurements of the agricultural materials, therefore providing tools for rapid evaluation of their water content and quality. There is a limited number of research in the field of dielectric spectroscopy of agricultural objects, which is caused by the relatively high cost of the respective measurement equipment. With the fast development of modern technology, especially in high frequency applications, dielectric spectroscopy has great potential of expansion in agrophysics, both in cognitive and utilitarian aspects.

  5. Characterization and Application of a Grazing Angle Objective for Quantitative Infrared Reflection Microspectroscopy

    NASA Technical Reports Server (NTRS)

    Pepper, Stephen V.

    1995-01-01

    A grazing angle objective on an infrared microspectrometer is studied for quantitative spectroscopy by considering the angular dependence of the incident intensity within the objective's angular aperture. The assumption that there is no angular dependence is tested by comparing the experimental reflectance of Si and KBr surfaces with the reflectance calculated by integrating the Fresnel reflection coefficient over the angular aperture under this assumption. Good agreement was found, indicating that the specular reflectance of surfaces can straight-forwardly be quantitatively integrated over the angular aperture without considering non-uniform incident intensity. This quantitative approach is applied to the thickness determination of dipcoated Krytox on gold. The infrared optical constants of both materials are known, allowing the integration to be carried out. The thickness obtained is in fair agreement with the value determined by ellipsometry in the visible. Therefore, this paper illustrates a method for more quantitative use of a grazing angle objective for infrared reflectance microspectroscopy.

  6. Rotational Spectroscopy Meets Theory

    NASA Astrophysics Data System (ADS)

    Puzzarini, Cristina

    2013-06-01

    Rotational spectroscopy is known to be a technique widely used to infer information on molecular structure and dynamics. In the last decades, its role in the field of atmospheric and astrophysical investigations has rapidly grown up. However, several are the challenging aspects in rotational spectroscopy, since the detection and analysis of spectra as well as interpretation of obtained results are not at all straightforward. Quantum chemistry has reached such an accuracy that can be used to disentangle these challenging situations by guiding the experimental investigation, assisting in the determination of the spectroscopic parameters, and extracting information of chemical interest. This presentation provides an overview of the theoretical background and computational requirements needed for the accurate evaluation of the spectroscopic parameters of relevance to rotational spectroscopy. The role of theory in guiding and supporting experiment is detailed through a few examples and the interplay of experiment and theory is discussed in terms of the information of physical and chemical interest that can be derived.

  7. Spectroscopy for the Masses

    NASA Astrophysics Data System (ADS)

    Le Roy, Robert J.; Hopkins, Scott; Power, William P.; Leung, Tong; Hepburn, John

    2015-06-01

    Undergraduate students in all areas of science encounter one or more types of spectroscopy as an essential tool in their discipline, but most never take the advanced physics or chemistry courses in which the subject is normally taught. To address this problem, for over 20 years our department has been teaching a popular Introductory Spectroscopy course that assumes as background only a one-term introductory chemistry course containing a unit on atomic theory, and a familiarity with rudimentary calculus. This survey course provides an introduction to microwave, infrared, Raman, electronic, photoelectron and NMR spectroscopy in a manner that allows students to understand many of these phenomena as intuitive generalizations of the problem of a particle in a 1-D box or a particle-on-a-ring, and does not require any high level mathematics.

  8. Application of External-Cavity Quantum Cascade Infrared Lasers to Nanosecond Time-Resolved Infrared Spectroscopy of Condensed-Phase Samples Following Pulse Radiolysis

    SciTech Connect

    Grills, D.C.; Cook, A.R.; Fujita, E.; George, M.W.; Miller, J.R.; Preses, J.M.; Wishart, J.F.

    2010-06-01

    Pulse radiolysis, utilizing short pulses of high-energy electrons from accelerators, is a powerful method for rapidly generating reduced or oxidized species and other free radicals in solution. Combined with fast time-resolved spectroscopic detection (typically in the ultraviolet/visible/near-infrared), it is invaluable for monitoring the reactivity of species subjected to radiolysis on timescales ranging from picoseconds to seconds. However, it is often difficult to identify the transient intermediates definitively due to a lack of structural information in the spectral bands. Time-resolved vibrational spectroscopy offers the structural specificity necessary for mechanistic investigations but has received only limited application in pulse radiolysis experiments. For example, time-resolved infrared (TRIR) spectroscopy has only been applied to a handful of gas-phase studies, limited mainly by several technical challenges. We have exploited recent developments in commercial external-cavity quantum cascade laser (EC-QCL) technology to construct a nanosecond TRIR apparatus that has allowed, for the first time, TRIR spectra to be recorded following pulse radiolysis of condensed-phase samples. Near single-shot sensitivity of DeltaOD <1 x 10(-3) has been achieved, with a response time of <20 ns. Using two continuous-wave EC-QCLs, the current apparatus covers a probe region from 1890-2084 cm(-1), and TRIR spectra are acquired on a point-by-point basis by recording transient absorption decay traces at specific IR wavelengths and combining these to generate spectral time slices. The utility of the apparatus has been demonstrated by monitoring the formation and decay of the one-electron reduced form of the CO(2) reduction catalyst, [Re(I)(bpy)(CO)(3)(CH(3)CN)](+), in acetonitrile with nanosecond time resolution following pulse radiolysis. Characteristic red-shifting of the nu(CO) IR bands confirmed that one-electron reduction of the complex took place. The availability of TRIR detection with high sensitivity opens up a wide range of mechanistic pulse radiolysis investigations that were previously difficult or impossible to perform with transient UV/visible detection.

  9. Advanced Spectroscopy Technique for Biomedicine

    NASA Astrophysics Data System (ADS)

    Zhao, Jianhua; Zeng, Haishan

    This chapter presents an overview of the applications of optical spectroscopy in biomedicine. We focus on the optical design aspects of advanced biomedical spectroscopy systems, Raman spectroscopy system in particular. Detailed components and system integration are provided. As examples, two real-time in vivo Raman spectroscopy systems, one for skin cancer detection and the other for endoscopic lung cancer detection, and an in vivo confocal Raman spectroscopy system for skin assessment are presented. The applications of Raman spectroscopy in cancer diagnosis of the skin, lung, colon, oral cavity, gastrointestinal tract, breast, and cervix are summarized.

  10. Advances in laser spectroscopy

    SciTech Connect

    Arecchi, F.T.; Strumia, F.; Walther, H.

    1983-01-01

    This book presents the lectures and seminars given at the NATO Study Institute on ''Advances in Laser Spectroscopy'' held in Italy in 1981. Topics include experimental and theoretical techniques (e.g., Rydberg atoms in magnetic and electric fields; progress in tunable lasers; UV-generation in CW dye lasers); applications of laser spectroscopy (e.g., new phenomena in coherent optical transients); and recent results and trends (e.g., the search for parity non-conservation in atoms; a possible new approach to free-electron lasers). Recommended for young researchers and advanced students engaged in the area of quantum electronics.

  11. Optical Modulation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kudrawiec, Robert; Misiewicz, Jan

    This chapter describes the principles of optical modulation spectroscopy. Special attention is focused on photo- and contactless electro-reflectance techniques, which are nondestructive for samples, and are widely applied to study the band structure of various semiconductor materials and low-dimensional heterostructures. For these methods, experimental setups are described and theoretical approaches to analyze the experimental data are discussed. In addition, examples of the application of photo- and contactless electro-reflectance spectroscopies to study optical transitions in III-V(-N) bulk-like epilayers, quantum wells, quantum dots, and device structures are presented.

  12. Spectroscopy of francium

    SciTech Connect

    Simsarian, J. E.; Grossman, J. S.; Orozco, L. A.; Pearson, M.; Sprouse, G. D.; Zhao, W. Z.

    1999-01-15

    Francium is the least studied of the alkali atoms because it has no stable isotopes. We have performed precision spectroscopy on cold Fr atoms in a magneto optical trap. We have determined the location of the first two excited states of the S series by two-photon spectroscopy. We have measured the lifetimes of the 7p levels with a precision better than 0.5%. Our measurements test the many-body perturbation theory ab initio calculations of the dipole matrix element to very high accuracy in this relativistic alkali.

  13. Quantifying low levels of polymorphic impurity in clopidogrel bisulphate by vibrational spectroscopy and chemometrics.

    PubMed

    Német, Zoltán; Demeter, Adám; Pokol, György

    2009-01-15

    Vibrational spectroscopic methods were developed for quantitative analysis of Form II of clopidogrel bisulphate in Form I and Form II polymorphic mixtures. Results show that both IR and Raman spectroscopy combined with chemometrics are suitable to quantify low levels of Form II in Form I, down to 2 and 3%, respectively, with less than 1% limit of detection. Different preprocessing and multivariate methods were applied for spectral processing and were compared to find the best chemometric model. Common problems of quantitative vibrational spectroscopy in the solid phase are discussed; and procedures appropriate to eliminate them are proposed. PMID:19019611

  14. Molecular dispersion spectroscopy – new capabilities in laser chemical sensing

    PubMed Central

    Nikodem, Michal; Wysocki, Gerard

    2012-01-01

    Laser spectroscopic techniques suitable for molecular dispersion sensing enable new applications and strategies in chemical detection. This paper discusses the current state-of-the art and provides an overview of recently developed chirped laser dispersion spectroscopy (CLaDS) based techniques. CLaDS and its derivatives allow for quantitative spectroscopy of trace-gases and enable new capabilities such as extended dynamic range of concentration measurements, high immunity to photodetected intensity fluctuations, or capability of direct processing of spectroscopic signals in optical domain. Several experimental configurations based on quantum cascade lasers and examples of molecular spectroscopic data are presented to demonstrate capabilities of molecular dispersion spectroscopy in the mid-infrared spectral region. PMID:22809459

  15. Identification of transgenic foods using NIR spectroscopy: A review

    NASA Astrophysics Data System (ADS)

    Alishahi, A.; Farahmand, H.; Prieto, N.; Cozzolino, D.

    2010-01-01

    The utilization of chemometric methods in the quantitative and qualitative analysis of feeds, foods, medicine and so on has been accompanied with the great evolution in the progress and in the near infrared spectroscopy (NIRS). Hence, recently the application of NIR spectroscopy has extended on the context of genetics and transgenic products. The aim of this review was to investigate the application of NIR spectroscopy to identificate transgenic products and to compare it with the traditional methods. The results of copious researches showed that the application of NIRS technology was successful to distinguish transgenic foods and it has advantages such as fast, avoiding time-consuming, non-destructive and low cost in relation to the antecedent methods such as PCR and ELISA.

  16. Clinical NIR spectroscopy and optical tomography of the testis

    NASA Astrophysics Data System (ADS)

    Hampel, Uwe; Schleicher, Eckhard; Zepnick, H.; Freyer, Richard

    2001-10-01

    Optical tomography and NIR spectroscopy are potential methods to improve the diagnosis of testicular pathologies. To evaluate the methods clinically we developed a special measurement device with the capability of spatially resolved laser spectroscopy and optical tomography of the testis. Simple spectroscopy is primarily used to obtain global tissue optical properties of the testis and to find correlations of optical parameters with type and stage of certain pathologies. Optical tomography is applied to visualize spectral contrasts in limited tissue volumes, such as tumors. In the course of the study we will determine whether NIR techniques posses the required specifity and sensitivity to give additional quantitative information about tissue perfusion parameters and to serve for a tumor differentiation.

  17. Photoacoustic spectroscopy of photoactive matter — Applications to photographic emulsions

    NASA Astrophysics Data System (ADS)

    Bohá?, L.; Fiala, J.; Pelant, I.; Sladký, P.; Vacek, K.

    1982-01-01

    A new technique — the photoacoustic spectroscopy with microphone detection has been successfully applied to the studies of spectral sensitivity of silver halide emulsions. Regardless of the fact that the sensitivity of photographic emulsions is greater or comparable with the detectivity of real photoacoustic transducers (i.e. the photoacoustic cell with microphone or piezoelectric transducer), absorption-like spectra of strongly diffusive and nontransparent silver halide emulsions can be readily recorded. Applications of this new technique for the studies of silver halide emulsions bears full potential advantages of photoacoustic spectroscopy. Particularly we demonstrate priority of the new technique over the conventional photographic sensitometry or reflectance spectroscopy both in qualitative and quantitative manner. Photoacoustic measurements of photochemical decomposition rates are shown and suggestions for the measurements of excitation energy transfer efficiencies are given. The results clearly show a unique applicability of the technique in fundamental as well as industrial research and process control of the photographic emulsion production.

  18. Quantitative Vibrational Dynamics of Iron in Carbonyl Porphyrins

    PubMed Central

    Leu, Bogdan M.; Silvernail, Nathan J.; Zgierski, Marek Z.; Wyllie, Graeme R. A.; Ellison, Mary K.; Scheidt, W. Robert; Zhao, Jiyong; Sturhahn, Wolfgang; Alp, E. Ercan; Sage, J. Timothy

    2007-01-01

    We use nuclear resonance vibrational spectroscopy and computational predictions based on density functional theory (DFT) to explore the vibrational dynamics of 57Fe in porphyrins that mimic the active sites of histidine-ligated heme proteins complexed with carbon monoxide. Nuclear resonance vibrational spectroscopy yields the complete vibrational spectrum of a Mössbauer isotope, and provides a valuable probe that is not only selective for protein active sites but quantifies the mean-squared amplitude and direction of the motion of the probe nucleus, in addition to vibrational frequencies. Quantitative comparison of the experimental results with DFT calculations provides a detailed, rigorous test of the vibrational predictions, which in turn provide a reliable description of the observed vibrational features. In addition to the well-studied stretching vibration of the Fe-CO bond, vibrations involving the Fe-imidazole bond, and the Fe-Npyr bonds to the pyrrole nitrogens of the porphyrin contribute prominently to the observed experimental signal. All of these frequencies show structural sensitivity to the corresponding bond lengths, but previous studies have failed to identify the latter vibrations, presumably because the coupling to the electronic excitation is too small in resonance Raman measurements. We also observe the FeCO bending vibrations, which are not Raman active for these unhindered model compounds. The observed Fe amplitude is strongly inconsistent with three-body oscillator descriptions of the FeCO fragment, but agrees quantitatively with DFT predictions. Over the past decade, quantum chemical calculations have suggested revised estimates of the importance of steric distortion of the bound CO in preventing poisoning of heme proteins by carbon monoxide. Quantitative agreement with the predicted frequency, amplitude, and direction of Fe motion for the FeCO bending vibrations provides direct experimental support for the quantum chemical description of the energetics of the FeCO unit. PMID:17350996

  19. Practical Analysis of materials with depth varying compositions using FT-IR photoacoustic spectroscopy (PAS)

    SciTech Connect

    J.F. McClelland; R.W. Jones; Siquan Luo

    2004-09-30

    FT-IR photoacoustic spectroscopy (PAS) is discussed as a nondestructive method to probe the molecular composition of materials versus depth on the basis of the analysis of layers of experimentally controllable thickness, which are measured from the sample surface to depths of some tens of micrometers, depending on optical and thermal properties. Computational methods are described to process photoacoustic amplitude and phase spectra for both semi-quantitative and quantitative depth analyses. These methods are demonstrated on layered and gradient samples.

  20. Quantitative phase imaging of arthropods.

    PubMed

    Sridharan, Shamira; Katz, Aron; Soto-Adames, Felipe; Popescu, Gabriel

    2015-11-01

    Classification of arthropods is performed by characterization of fine features such as setae and cuticles. An unstained whole arthropod specimen mounted on a slide can be preserved for many decades, but is difficult to study since current methods require sample manipulation or tedious image processing. Spatial light interference microscopy (SLIM) is a quantitative phase imaging (QPI) technique that is an add-on module to a commercial phase contrast microscope. We use SLIM to image a whole organism springtail Ceratophysella denticulata mounted on a slide. This is the first time, to our knowledge, that an entire organism has been imaged using QPI. We also demonstrate the ability of SLIM to image fine structures in addition to providing quantitative data that cannot be obtained by traditional bright field microscopy. PMID:26334858