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Sample records for matrix isolation ftir

  1. Structure of isothiocyanic acid dimers. Theoretical and FTIR matrix isolation studies

    NASA Astrophysics Data System (ADS)

    Krupa, Justyna; Wierzejewska, Maria

    2016-05-01

    A quantum mechanical study of the potential energy surface for the HNCS dimer is reported. The calculations were performed using DFT and ab initio MP2 methods. The most stable is a cyclic form with a double N-H⋯S interaction and the interaction energy in the range of 16.91-18.92 kJ mol-1. An open HNCS dimer bound by the N-H⋯N hydrogen bond is by ca 3.3-5.1 kJ mol-1 less stable. Experimental FTIR matrix isolation studies of HNCS/N2 system show that exclusively less stable open dimer is formed in solid nitrogen. Possible reasons for the observed discrepancy between theory and experiment are discussed.

  2. Conformational Analysis of 1-ALKENE Secondary Ozonides by Means of Matrix Isolation FTIR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sablinskas, Valdas; Strazdaite, Simona; Ceponkus, Justinas

    2009-06-01

    An ability of ozone to break double C=C bond in olefins is known for more than five decades. Understanding of those reactions is very important in atmospheric chemistry. During different steps of the reaction the primary ozonide (POZ), carbonyl oxide (COX) and the secondary ozonide (SOZ) are formed. Fate of the reaction depends on many parameters such as type of radical, conformation of alkene, temperature of the reaction and environmental effects. Despite of numerous studies of the reaction by different spectroscopic techniques the precise mechanism of the reaction is still unknown. It is experimentally observed that the SOZ is more stable than POZ. Stability of the SOZ depends on the size and configuration of the radical. Unfortunately, it is not much known about the spatial structures of the SOZ'es. The aim of this study is to define the geometrical structures and stability of the different conformers of the 1-butene and 1-heptene secondary ozonides by combined analysis of the matrix isolation FTIR spectral data with the results of Density Functional Theory (DFT) calculations.

  3. Theoretical DFT and matrix isolation FTIR studies of 2-(1,2,4-triazolyl)phenol isomers

    NASA Astrophysics Data System (ADS)

    Pagacz-Kostrzewa, Magdalena; Sałdyka, Magdalena; Wierzejewska, Maria; Khomenko, Dmytro M.; Doroschuk, Roman O.

    2016-07-01

    The structure, isomerization pathways and vibrational spectra of the important heterocyclic 2-(1,2,4-triazolyl)phenol molecule were investigated by DFT calculations and matrix isolation FTIR spectroscopy. Among forty-five minima located on PES three isomers with intramolecular hydrogen bond Osbnd H⋯N, 2-TRP1, 1-TRP1 and 1-TRP2, are the most stable forms with the calculated abundance of 83.4%, 10.3% and 6.0%, respectively. The presented FTIR results allow identification and characterization of these species. Several hydrogen bond parameters such as OH bond distance, νOH wavenumber shift and occupancy of the antibonding σ∗(OH) orbital were found to be linearly related with the estimated interaction energy.

  4. Crystal structure, matrix-isolation FTIR, and UV-induced conformational isomerization of 3-quinolinecarboxaldehyde.

    PubMed

    Kuş, Nihal; Henriques, Marta Sofia; Paixão, José António; Lapinski, Leszek; Fausto, Rui

    2014-09-25

    The crystal structure of 3-quinolinecarboxaldehyde (3QC) has been solved, and the compound has been shown to crystallize in the space group P21/c (monoclinic) with a = 6.306(4), b = 18.551(11), c = 6.999(4) Å, β = 106.111(13)°, and Z = 4. The crystals were found to exhibit pseudomerohedral twinning with a twin law corresponding to a two-fold rotation around the monoclinic (100) reciprocal lattice axis (or [4 0 1] in direct space). Individual molecules adopt the syn conformation in the crystal, with the oxygen atom of the aldehyde substituent directed toward the same side of the ring nitrogen atom. In the gas phase, the compound exists in two nearly isoenergetic conformers (syn and anti), which could be successfully trapped in solid argon at 10 K, and their infrared spectra are registered and interpreted. Upon in situ irradiation of matrix-isolated 3QC with UV light (λ > 315 nm), significant reduction of the population of the less stable anti conformer was observed, while that of the conformational ground state (syn conformer) increased, indicating occurrence of the anti → syn isomerization. Upon irradiation at higher energy (λ > 235 nm), the syn → anti reverse photoreaction was observed. Interpretation of the structural, spectroscopic, and photochemical experimental data received support from quantum chemical theoretical results obtained at both DFT/B3LYP (including TD-DFT investigation of excited states) and MP2 levels, using the 6-311++G(d,p) basis set. PMID:25144919

  5. The OH-Initiated Oxidation of CS2 in the Presence of NO: FTIR Matrix-Isolation and Theoretical Studies.

    PubMed

    Bil, A; Grzechnik, K; Sałdyka, M; Mielke, Z

    2016-09-01

    We studied the photochemistry of the carbon disulfide-nitrous acid system with the help of Fourier transform infrared (FTIR) matrix isolation spectroscopy and theoretical methods. The irradiation of the CS2···HONO complexes, isolated in solid argon, with the filtered output of the mercury lamp (λ > 345 nm) was found to produce OCS, SO2, and HNCS; HSCN was also tentatively identified. The (13)C, (15)N, and (2)H isotopic shifts as well as literature data were used for product identifications. The evolution of the measured FTIR spectra with irradiation time and the changes in the spectra after matrix annealing indicated that the identified molecules are the products of different reaction channels: OCS being a product of another reaction path than SO2 and HNCS or HSCN. The possible reaction channels between SC(OH)S/SCS(OH) radicals and NO were studied using DFT/B3LYP/aug-cc-pVTZ method. The SC(OH)S and/or SCS(OH) intermediates are formed when HONO attached to CS2 photodissociates into OH and NO. The calculations indicated that SC(OH)S radical can form with NO two stable adducts. The more stable SC(OH)S···NO structure is a reactant for a simple one-step process leading to OCS and HONS molecules. An alternative, less-stable complex formed between SC(OH)S and NO leads to formation of OCS and HSNO. The calculations predict only one stable complex between SCS(OH) radical and NO, which can dissociate along two channels leading to HNCS and SO2 or HSCN and SO2 as the end products. The identified photoproducts indicate that both SC(OH)S and SCS(OH) adducts are intermediates in the CS2 + OH + NO reaction leading to different reaction products. PMID:27491274

  6. A theoretical and matrix-isolation FT-IR investigation of the conformational landscape of N-acetylcysteine

    NASA Astrophysics Data System (ADS)

    Boeckx, Bram; Ramaekers, Riet; Maes, Guido

    2010-06-01

    The conformational landscape of N-acetylcysteine (NAC) has been investigated by a combined experimental matrix-isolation FT-IR and theoretical methodology. This combination is a powerful tool to study the conformational behavior of relatively small molecules. Geometry optimizations at the HF/3-21 level resulted in 438 different geometries with an energy difference smaller than 22 kJ mol -1. Among these, six conformations were detected with a relative energy difference smaller than 10 kJ mol -1 at the DFT(B3LYP)/6-31++G∗∗ level of theory. These were finally subjected to MP2/6-31++G∗∗ optimizations which resulted in five minima. The vibrational and thermodynamical properties of these conformations were calculated at both the DFT and MP2 methodologies. Experimentally NAC was isolated in an argon matrix at 16 K after being sublimated at 323 K. The most stable MP2 form appeared to be dominant in the experimental spectra but the presence of three other conformations with Δ EMP2 < 10 kJ mol -1 was also demonstrated. The experimentally observed abundance of the H-bond containing conformations appeared to be in good accordance with the predicted MP2 value.

  7. C dbnd N sbnd N dbnd C conformational isomers of 2'-hydroxyacetophenone azine: FTIR matrix isolation and DFT study

    NASA Astrophysics Data System (ADS)

    Grzegorzek, Joanna; Mielke, Zofia; Filarowski, Aleksander

    2010-07-01

    2'-hydroxyacetophenone azine (APA) has been studied by matrix isolation infrared spectroscopy and quantum chemical calculations. The DFT/B3LYP/6-311++G(2d,2p) calculations demonstrated the existence of two conformers for the lowest energy E/ E configuration of APA, a s- trans and a gauche ones. The conformers are characterized by similar energies and differ in the value of a C dbnd N sbnd N dbnd C angle, that was calculated to be 180° for a planar s-trans conformer and 155° for a non-planar gauche one . The calculated barrier for conformational interconversion is also very low, ca. 1 kJ mol -1 for the conversion from a gauche conformer to a trans one. The FTIR spectra of an argon matrix doped with APA from a vapour above solid sample evidence the presence of both conformers that exhibit reversible interconversion at matrix temperatures. The comparison of the theoretical spectra with the experimental ones and reversible temperature dependence of the experimental spectra allowed for unambiguous spectroscopic characterization of the trans and gauche conformers. The experiment also demonstrated that a gauche conformer is more stable than a trans one. The spectra analysis indicates that transformation from a trans conformer to a gauche one weakens the intramolecular O sbnd H⋯N bonds in the molecule.

  8. Matrix-isolation FT-IR and theoretical investigation of the vibrational properties of the sterically hindered ortho-hydroxy acylaromatic Schiff bases

    NASA Astrophysics Data System (ADS)

    Pajak, J.; Maes, G.; De Borggraeve, W. M.; Boens, N.; Filarowski, A.

    2007-11-01

    FT-IR and FT-Raman spectra of the ortho-hydroxy acylaromatic Schiff bases (2-(α-( N-methylimino)ethyl)-4-chloro-6-nitrophenol - I, 2-(α-( N-methylimino)ethyl)-4,6-dichlorophenol - II), and their isotoposubstitutions have been recorded in the range of 4000-50 cm -1. The spectra were interpreted by a normal coordinate analysis based on B3LYP/6-31++G(d,p) density functional calculations and experimental deuterosubstitution. Proton transfer equilibrium between the enolic and keto tautomers of two sterically hindered Schiff bases has been studied combined experimental (FT-IR matrix-isolation and FT-Raman) and theoretical (DFT/B3LYP/6-31++G(d,p)) methods.

  9. Matrix Isolation FTIR and AB Initio Studies on the Conformations of Dimethyl and Diethyl Carbonate and Their Complexes with Water

    NASA Astrophysics Data System (ADS)

    Kar, Bishnu Prasad; Ramanathan, N.; Sundararajan, K.; Viswanathan, K. S.

    2011-06-01

    Dimethyl carbonate (DMC) and diethyl carbonate (DEC) have been studied for their conformations using matrix isolation infrared spectroscopy and ab initio computations. In addition to the above studies, the complexes of the two compounds with water have also been studied. The experiments were corroborated with ab initio calculations at the B3LYP/6-31++G** level. The organic carbonates were trapped in argon and nitrogen matrixes using an effusive source maintained at two different temperatures; i.e. room temperature and 170°C. In addition the matrix was also deposited using a supersonic jet source. These experiments were performed to alter the relative population of the various conformations, to aid us in the assignments of the vibrational features. The conformation of DMC corresponding to the global minimum of DMC was found to be a cis-cis conformer where the two methyl groups are found to be at cis position with respect to the carbonyl oxygen. The next higher energy conformer corresponded to a cis-trans structure with a near trans-near trans structure being the highest energy conformer. In our experimental matrix isolation spectra of DMC, we were able to assign features due to the cis-cis and cis-trans conformers. The features of the higher energy cis-trans conformer was confirmed with our experiments using the elevated temperature effusive source and the supersonic source. DEC displays a richer conformational landscape due to the presence of a longer carbon chain. The computational and experimental indicate that the ground state conformer for this compound is one in which carbon attached to oxygen adopts a cis configuration with respect to the carbonyl oxygen, while the terminal carbon adopts an anti conformation. A detailed study of the conformational picture of DEC will be presented. In addition to the above conformational studies, 1:1 hydrogen bonded complexes of DMC and DEC with water were also observed in the matrix, which was corroborated by our

  10. Gas chromatographic/matrix isolation/FTIR studies of decomposition products of Irganox 1010 in an aqueous ethanol system

    NASA Astrophysics Data System (ADS)

    Chen, Jo-Yun T.; Mossoba, Madgi M.; Varner, S. L.; Roach, J. A.; Sphon, J. A.; Page, Samuel W.

    1989-12-01

    Irganox 1010 is an antioxidant used in food packaging. The degradation products of Irganox 1010 in a 50% aqueous ethanol system at 90C were examined by GC/MS and GC/MI/FTIR. The data suggest Irganox 10101 is hydrolyzed to form (3) benzenepropanoic acid, 3,5-bis (1,1-dimethylethyl)4-hydroxy-which reacts with solvent ethanol to form (f) its ethyl ester. The 4 other decomposition products (a) 2.5 cyclohexadiene-I,4-dione, 2,6-bis(1.1-dimethylethyl)-; (B) 3.5-bis-(1,1,-dimethylethyl)-2.5 cyclohexadiene-4-one spiro (5'-tetrahydrofuran-2'-one); (C) benzofuran, 2,3-dihydro-3.3-dimethyl-5 ethenyl-7-(1,1-dimethylethyl)-and (D) benzaldehyede, 3.5-bis-(1,1-dimethylethyl)-4-hydroxy-, can result from osidation, dehydration and decarboxylation processes of (E).

  11. Cryogenic neon matrix-isolation FTIR spectroscopy of evaporated ionic liquids: geometrical structure of cation-anion 1:1 pair in the gas phase.

    PubMed

    Akai, Nobuyuki; Parazs, David; Kawai, Akio; Shibuya, Kazuhiko

    2009-04-01

    Low-temperature infrared spectra of thermally evaporated ionic liquids, 1-ethyl- and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and bis(trifluoromethanesulfonyl)amide have been measured in a cryogenic Ne matrix. The experimental IR spectrum of bis(trifluoromethanesulfonyl)amide can be reproduced theoretically by not B3LYP/6-31G* but MP2/6-31G* calculation, which suggests that the vibrational analysis for ionic liquids composed of bis(trifluoromethanesulfonyl)imide anion would be more successfully performed using the MP2 calculation. By comparison of the matrix-isolation spectra of the ionic liquids with the MP2 calculation, their geometrical structures in the gas phase are determined to be of C(2-position)-H(+)...N(-) interaction structure, which corresponds to the geometry of the energetically second-lowest ion-pair structure. The present study may provide a valuable clue to understand a vaporization mechanism of ionic liquid. PMID:19281187

  12. Conformational isomerism of pyridoxal. Infrared matrix isolation and theoretical studies

    NASA Astrophysics Data System (ADS)

    Kwiatek, Anna; Mielke, Zofia

    2015-01-01

    A combined matrix isolation FTIR and theoretical DFT/B3LYP/6-311++G(2p,2d) study of pyridoxal was performed. The calculations resulted in five stable PLHB conformers stabilized by intramolecular Osbnd H⋯O bonding between phenolic OH and carbonyl Cdbnd O groups and another thirteen conformers in which OH or/and aldehyde groups are rotated by 180° around CO or/and CC bonds leading, respectively, to formation of PLO, PLA and PLOA conformers. The analysis of the spectra of the as-deposited matrix indicated that two most stable PLHB1 and PLHB2 conformers with intramolecular hydrogen bond are present in the matrix. The exposure of the PL/Ar matrix to mercury lamp radiation (λ > 345 nm) induced conformational change of PLHB isomers to PLOA ones.

  13. Conformational isomerism of pyridoxal. Infrared matrix isolation and theoretical studies.

    PubMed

    Kwiatek, Anna; Mielke, Zofia

    2015-01-25

    A combined matrix isolation FTIR and theoretical DFT/B3LYP/6-311++G(2p,2d) study of pyridoxal was performed. The calculations resulted in five stable PLHB conformers stabilized by intramolecular O-H⋯O bonding between phenolic OH and carbonyl C=O groups and another thirteen conformers in which OH or/and aldehyde groups are rotated by 180° around CO or/and CC bonds leading, respectively, to formation of PLO, PLA and PLOA conformers. The analysis of the spectra of the as-deposited matrix indicated that two most stable PLHB1 and PLHB2 conformers with intramolecular hydrogen bond are present in the matrix. The exposure of the PL/Ar matrix to mercury lamp radiation (λ>345 nm) induced conformational change of PLHB isomers to PLOA ones. PMID:25173527

  14. FTIR spectra and conformational structure of deutero-β-alanine isolated in argon matrices

    NASA Astrophysics Data System (ADS)

    Stepanian, Stepan G.; Ivanov, Alexander Yu; Adamowicz, Ludwik

    2016-02-01

    Low temperature FTIR spectra of β-alanine-d3 isolated in argon matrices are used to determine the conformational composition of this compound. UV irradiation of the matrix samples is found to change the relative populations of the β-alanine-d3 conformers. The populations of conformers I and II with an Nsbnd D⋯O intramolecular H-bond decrease after the UV irradiation while the populations of conformer V with an N⋯Dsbnd O H-bond and conformer IV which has no intramolecular H-bonds increase. This behavior of the β-alanine-d3 conformers are used to separate the bands of the different conformers. The analysis of the experimental FTIR spectra is based on the calculated harmonic B3LYP/6-311++G(df,pd) frequencies and on the MP2/aug-cc-pVDZ frequencies calculated with a method that includes anharmonic effects. Polynomial scaling of the calculated frequencies is used to achieve better agreement with the experimental data. The observation of the wide band of the OD stretching vibration at 2201 cm-1 is a direct evidence of the presence of the β-alanine-d3 conformer V in the Ar matrix. In total ten bands of conformer V are detected. The influence of the matrix environment on the structures and the IR spectra of the β-alanine and β-alanine-d3 conformers is investigated. This involves performing calculations of the β-alanine conformers embedded in argon clusters containing from 163 to 166 argon atoms using the M06-2X and B3LYP(GD3BJ) density-functional methods. Good agreement between the calculated and the experimental matrix splitting is demonstrated.

  15. Matrix isolation as a tool for studying interstellar chemical reactions

    NASA Technical Reports Server (NTRS)

    Ball, David W.; Ortman, Bryan J.; Hauge, Robert H.; Margrave, John L.

    1989-01-01

    Since the identification of the OH radical as an interstellar species, over 50 molecular species were identified as interstellar denizens. While identification of new species appears straightforward, an explanation for their mechanisms of formation is not. Most astronomers concede that large bodies like interstellar dust grains are necessary for adsorption of molecules and their energies of reactions, but many of the mechanistic steps are unknown and speculative. It is proposed that data from matrix isolation experiments involving the reactions of refractory materials (especially C, Si, and Fe atoms and clusters) with small molecules (mainly H2, H2O, CO, CO2) are particularly applicable to explaining mechanistic details of likely interstellar chemical reactions. In many cases, matrix isolation techniques are the sole method of studying such reactions; also in many cases, complexations and bond rearrangements yield molecules never before observed. The study of these reactions thus provides a logical basis for the mechanisms of interstellar reactions. A list of reactions is presented that would simulate interstellar chemical reactions. These reactions were studied using FTIR-matrix isolation techniques.

  16. Gas chromatography/matrix-isolation apparatus

    DOEpatents

    Reedy, Gerald T.

    1986-01-01

    A gas-sample collection device provides matrix isolation of individual gas bands from a gas chromatographic separation and for the spectroscopic analysis of the individual sample bands. The device includes a vacuum chamber containing a rotatably supported, specular carousel having at least one reflecting surface for holding a sample deposited thereon. A gas inlet is provided for depositing a mixture of sample and matrix material on the reflecting surface which is maintained at a sufficiently low temperature to cause solidification. A first parabolic mirror directs an incident beam of electromagnetic radiation, such as in the infrared (IR) spectrum, from a source onto the sample/matrix mixture while a second parabolic mirror directs a second beam of electromagnetic radiation reflected by the specular surface to an IR spectrometer for determining the absorption spectra of the sample material deposited on the reflecting surface. The pair of off-axis parabolic mirrors having a common focal point are positioned outside of the vacuum chamber and may be displaced in combination for improved beam positioning and alignment. The carousel is provided with an aperture for each reflecting surface to facilitate accurate positioning of the incident beam relative to the gas-samples under analysis. Improved gas-sample deposition is insured by the use of a long focal length stereomicroscope positioned outside of the vacuum chamber for monitoring sample formation through a window, while the sample collector is positioned outside of the zone bounded by the incident and reflected electromagnetic beams for improved sample access and monitoring.

  17. Gas chromatography/matrix-isolation apparatus

    DOEpatents

    Reedy, G.T.

    1986-06-10

    A gas-sample collection device provides matrix isolation of individual gas bands from a gas chromatographic separation and for the spectroscopic analysis of the individual sample bands. The device includes a vacuum chamber containing a rotatably supported, specular carousel having at least one reflecting surface for holding a sample deposited thereon. A gas inlet is provided for depositing a mixture of sample and matrix material on the reflecting surface which is maintained at a sufficiently low temperature to cause solidification. A first parabolic mirror directs an incident beam of electromagnetic radiation, such as in the infrared (IR) spectrum, from a source onto the sample/matrix mixture while a second parabolic mirror directs a second beam of electromagnetic radiation reflected by the specular surface to an IR spectrometer for determining the absorption spectra of the sample material deposited on the reflecting surface. The pair of off-axis parabolic mirrors having a common focal point are positioned outside of the vacuum chamber and may be displaced in combination for improved beam positioning and alignment. The carousel is provided with an aperture for each reflecting surface to facilitate accurate positioning of the incident beam relative to the gas-samples under analysis. Improved gas-sample deposition is insured by the use of a long focal length stereomicroscope positioned outside of the vacuum chamber for monitoring sample formation through a window, while the sample collector is positioned outside of the zone bounded by the incident and reflected electromagnetic beams for improved sample access and monitoring. 10 figs.

  18. Detection and differentiation of bacterial spores in a mineral matrix by Fourier transform infrared spectroscopy (FTIR) and chemometrical data treatment

    PubMed Central

    2011-01-01

    Background Fourier transform infrared spectroscopy (FTIR) has been used as analytical tool in chemistry for many years. In addition, FTIR can also be applied as a rapid and non-invasive method to detect and identify microorganisms. The specific and fingerprint-like spectra allow - under optimal conditions - discrimination down to the species level. The aim of this study was to develop a fast and reproducible non-molecular method to differentiate pure samples of Bacillus spores originating from different species as well as to identify spores in a simple matrix, such as the clay mineral, bentonite. Results We investigated spores from pure cultures of seven different Bacillus species by FTIR in reflection or transmission mode followed by chemometrical data treatment. All species investigated (B. atrophaeus, B. brevis, B. circulans, B. lentus, B. megaterium, B. subtilis, B. thuringiensis) are typical aerobic soil-borne spore formers. Additionally, a solid matrix (bentonite) and mixtures of benonite with spores of B. megaterium at various wt/wt ratios were included in the study. Both hierarchical cluster analysis and principal component analysis of the spectra along with multidimensional scaling allowed the discrimination of different species and spore-matrix-mixtures. Conclusions Our results show that FTIR spectroscopy is a fast method for species-level discrimination of Bacillus spores. Spores were still detectable in the presence of the clay mineral bentonite. Even a tenfold excess of bentonite (corresponding to 2.1 × 1010 colony forming units per gram of mineral matrix) still resulted in an unambiguous identification of B. megaterium spores. PMID:21756333

  19. Rapid Isolation of Phenol Degrading Bacteria by Fourier Transform Infrared (FTIR) Spectroscopy.

    PubMed

    Li, Fei; Song, Wen-jun; Wei, Ji-ping; Wang, Su-ying; Liu, Chong-ji

    2015-05-01

    Phenol is an important chemical engineering material and ubiquitous in industry wastewater, its existence has become a thorny issue in many developed and developing country. More and more stringent standards for effluent all over the world with human realizing the toxicity of phenol have been announced. Many advanced biological methods are applied to industrial wastewater treatment with low cost, high efficiency and no secondary pollution, but the screening of function microorganisms is certain cumbersome process. In our study a rapid procedure devised for screening bacteria on solid medium can degrade phenol coupled with attenuated total reflection fourier transform infrared (ATR-FTIR) which is a detection method has the characteristics of efficient, fast, high fingerprint were used. Principal component analysis (PCA) is a method in common use to extract fingerprint peaks effectively, it couples with partial least squares (PLS) statistical method could establish a credible model. The model we created using PCA-PLS can reach 99. 5% of coefficient determination and validation data get 99. 4%, which shows the promising fitness and forecasting of the model. The high fitting model is used for predicting the concentration of phenol at solid medium where the bacteria were grown. The highly consistent result of two screening methods, solid cultural with ATR-FTIR detected and traditional liquid cultural detected by GC methods, suggests the former can rapid isolate the bacteria which can degrade substrates as well as traditional cumbersome liquid cultural method. Many hazardous substrates widely existed in industry wastewater, most of them has specialize fingerprint peaks detected by ATR-FTIR, thereby this detected method could be used as a rapid detection for isolation of functional microorganisms those can degrade many other toxic substrates. PMID:26415432

  20. Rapid characterisation of Klebsiella oxytoca isolates from contaminated liquid hand soap using mass spectrometry, FTIR and Raman spectroscopy.

    PubMed

    Dieckmann, Ralf; Hammerl, Jens Andre; Hahmann, Hartmut; Wicke, Amal; Kleta, Sylvia; Dabrowski, Piotr Wojciech; Nitsche, Andreas; Stämmler, Maren; Al Dahouk, Sascha; Lasch, Peter

    2016-06-23

    Microbiological monitoring of consumer products and the efficiency of early warning systems and outbreak investigations depend on the rapid identification and strain characterisation of pathogens posing risks to the health and safety of consumers. This study evaluates the potential of three rapid analytical techniques for identification and subtyping of bacterial isolates obtained from a liquid hand soap product, which has been recalled and reported through the EU RAPEX system due to its severe bacterial contamination. Ten isolates recovered from two bottles of the product were identified as Klebsiella oxytoca and subtyped using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI TOF MS), near-infrared Fourier transform (NIR FT) Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. Comparison of the classification results obtained by these phenotype-based techniques with outcomes of the DNA-based methods pulsed-field gel electrophoresis (PFGE), multi-locus sequence typing (MLST) and single nucleotide polymorphism (SNP) analysis of whole-genome sequencing (WGS) data revealed a high level of concordance. In conclusion, a set of analytical techniques might be useful for rapid, reliable and cost-effective microbial typing to ensure safe consumer products and allow source tracking. PMID:27053001

  1. Bone matrix calcification during embryonic and postembryonic rat calvarial development assessed by SEM-EDX spectroscopy, XRD, and FTIR spectroscopy.

    PubMed

    Henmi, Akiko; Okata, Hiroshi; Anada, Takahisa; Yoshinari, Mariko; Mikami, Yasuto; Suzuki, Osamu; Sasano, Yasuyuki

    2016-01-01

    Bone mineral is constituted of biological hydroxyapatite crystals. In developing bone, the mineral crystal matures and the Ca/P ratio increases. However, how an increase in the Ca/P ratio is involved in maturation of the crystal is not known. The relationships among organic components and mineral changes are also unclear. The study was designed to investigate the process of calcification during rat calvarial bone development. Calcification was evaluated by analyzing the atomic distribution and concentration of Ca, P, and C with scanning electron microscopy (SEM)-energy-dispersive X-ray (EDX) spectroscopy and changes in the crystal structure with X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Histological analysis showed that rat calvarial bone formation started around embryonic day 16. The areas of Ca and P expanded, matching the region of the developing bone matrix, whereas the area of C became localized around bone. X-ray diffraction and FTIR analysis showed that the amorphous-like structure of the minerals at embryonic day 16 gradually transformed into poorly crystalline hydroxyapatite, whereas the proportion of mineral to protein increased until postnatal week 6. FTIR analysis also showed that crystallization of hydroxyapatite started around embryonic day 20, by which time SEM-EDX spectroscopy showed that the Ca/P ratio had increased and the C/Ca and C/P ratios had decreased significantly. The study suggests that the Ca/P molar ratio increases and the proportion of organic components such as proteins of the bone matrix decreases during the early stage of calcification, whereas crystal maturation continues throughout embryonic and postembryonic bone development. PMID:25773047

  2. Graphite matrix materials for nuclear waste isolation

    SciTech Connect

    Morgan, W.C.

    1981-06-01

    At low temperatures, graphites are chemically inert to all but the strongest oxidizing agents. The raw materials from which artificial graphites are produced are plentiful and inexpensive. Morover, the physical properties of artificial graphites can be varied over a very wide range by the choice of raw materials and manufacturing processes. Manufacturing processes are reviewed herein, with primary emphasis on those processes which might be used to produce a graphite matrix for the waste forms. The approach, recommended herein, involves the low-temperature compaction of a finely ground powder produced from graphitized petroleum coke. The resultant compacts should have fairly good strength, low permeability to both liquids and gases, and anisotropic physical properties. In particular, the anisotropy of the thermal expansion coefficients and the thermal conductivity should be advantageous for this application. With two possible exceptions, the graphite matrix appears to be superior to the metal alloy matrices which have been recommended in prior studies. The two possible exceptions are the requirements on strength and permeability; both requirements will be strongly influenced by the containment design, including the choice of materials and the waste form, of the multibarrier package. Various methods for increasing the strength, and for decreasing the permeability of the matrix, are reviewed and discussed in the sections in Incorporation of Other Materials and Elimination of Porosity. However, it would be premature to recommend a particular process until the overall multi-barrier design is better defined. It is recommended that increased emphasis be placed on further development of the low-temperature compacted graphite matrix concept.

  3. Iron pentacarbonyl detection limits in the cigarette smoke matrix using FT-IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Parrish, Milton E.; Plunkett, Susan E.; Harward, Charles N.

    2005-11-01

    Endogenous metals present in tobacco from agricultural practices have been purported to generate metal carbonyls in cigarette smoke. Transition metal catalysts, such as iron oxide, have been investigated for the reduction of carbon monoxide (CO) in cigarette smoke. These studies motivated the development of an analytical method to determine if iron pentacarbonyl [Fe(CO) 5] is present in mainstream smoke from cigarette models having cigarette paper made with iron oxide. An FT-IR puff-by-puff method was developed and the detection limit was determined using two primary reference spectra from different sources to estimate the amount of Fe(CO) 5 present in a high-pressure steel cylinder of CO. We do not detect Fe(CO) 5 in a single 35 mL puff from reference cigarettes or from those cigarette models having cigarette paper made with iron oxide, with a 30-ppbV limit of detection (LOD). Also, it was shown that a filter containing activated carbon would remove Fe(CO) 5.

  4. FTIR Studies of the Photochemistry of Deuterated Formic Acid in a Parahydrogen Matrix

    NASA Astrophysics Data System (ADS)

    Anderson, David T.

    2014-06-01

    We report new FTIR studies of the 193 nm photochemistry of deuterated formic acid (DCOOD) trapped in parahydrogen matrices. In our 2011 preliminary report, we showed the 193 nm in situ photolysis of formic acid (HCOOH) produces small amounts of HCO and HOCO and that after the laser is turned off, we observe continued slow growth in the HOCO radical for up to 10 hours after photolysis. At that time we were unsure of the detailed chemical mechanism by which the HOCO continues to grow after photolysis, but we suspected it had to do with reactions of mobile H-atoms with the HCOOH precursor that remains at significant concentrations after photolysis under these conditions. The present deuterated formic acid photolysis studies provide strong circumstantial evidence that H-atom reactions with formic acid are the source of the continued HOCO growth. Further, variable-temperature kinetic studies conducted with the deuterated formic acid sample show a strong inverse temperature dependence to the reaction kinetics. Essentially, the reaction that leads to HOCO growth only occurs at temperatures below 2.4 K. We are currently trying to model the kinetics using standard methods and the most recent analysis will be presented at the meeting. David T. Anderson, Leif O. Paulson, 66th Ohio State University International Symposium on Molecular Spectroscopy, talk FE02 (2011).

  5. EPR, FTIR, and FAB mass spectrometric investigation of reaction of H atoms with C 60 in a cyclohexane matrix

    NASA Astrophysics Data System (ADS)

    Howard, J. A.

    1993-03-01

    Hydrogen atoms have been reacted with C 60 in a cyclohexane matrix at 77 K in a rotating cryostat. Species HC 60, H 2 n + 1 C 60, and H 2 nC 60 have been identified by EPR, FTIR and FAB mass spectrometry. HC 60 has the magnetic parameters aH(1) = 92.9 ± 0.5 MHz and g = 2.00218 ± 0.00004. These values are compared to the deuterium and muonium analogs. Reasons for the isotope effect in the hydrogen and muon hyperfine interactions of HC 60 and MuC 60 are discussed. The narrow line widths of the EPR transitions of H 2 n + 1C 60 may be associated with globe-trotting hydrogen atoms. C 60 acts as a H atom sponge at high atom fluxes and H 2 nC 60s with n as large as 17 have been identified.

  6. Matrix Resin Characterization in Cured Graphite Composites Using Diffuse Reflectance-Ftir

    NASA Technical Reports Server (NTRS)

    Young, P. R.; Chang, A. C.

    1984-01-01

    The chemical characterization of cured graphite fiber reinforced polymer matrix composites is complicated by the fact that the resins are insoluble and the composites are apaque. Standard analyses which depend either on the ability to dissolve the sample or to detect transmitted radiation are impossible. As a result, data reported on environmentally exposed composites primarily concern macroscopic information such as weight loss or changes in selected mechanical properties. Diffuse reflectance in combination with fourier transform infrared spectroscopy was developed to gain a basic chemical understanding of composite and adhesive behavior. Several composite and adhesive materials were characterized before and after environmental exposure. In each case significant changes in resin molecular structure were observed and correlated with changes in mechanical properties, providing new insights into material performance.

  7. Degeneracy Lifting Effect in the FTIR Spectrum of Fluoroform Trapped in a Nitrogen Matrix. An Experimental and Car-Parrinello Molecular Dynamics Study.

    PubMed

    Asfin, Ruslan E; Melikova, Sona M; Domanskaya, Alexandra V; Rodziewicz, Paweł; Rutkowski, Konstantin S

    2016-05-26

    The FTIR spectra of fluoroform trapped in argon and nitrogen matrixes are studied at T ∼ 10-30 K. The bands of E symmetry show the splitting effect in a nitrogen matrix, which is absent in an argon matrix. The effect is the most prominent in the case of the ν4 CH bending vibration. It decreases slightly with increasing temperature. Both static and Car-Parrinello molecular dynamic simulations suggest that the degeneracy lifting is due to C3v symmetry lowering caused by interactions between fluoroform and all neighbor N2 matrix molecules. PMID:27149085

  8. Examinations Of The Matrix Isolation Fourier Transform Infrared Spectra Of Organic Compounds.

    NASA Astrophysics Data System (ADS)

    Coleman, W. M.

    1989-12-01

    Matrix isolation Fourier transform infrared spectra (MI/FT-IR), mass spectra (MS), carbon-13 Nuclear Magnetic Resonance (13C-NMR) spectra, condensed phase infrared spectra and vapor phase infrared (IR) spectra are presented for a series of terpene compounds. Subtle differences in positional and configurational isomers commonly found with terpenes could be easily detected by the. MI/FT-IR spqctra. The results are comparable in some aspects to those obtainable from IJC-NMR and thin film IR, however, most importantly, they are acquired at the low nanogram level for MI/FTIR as compared to the milligram level for the other techniques. These results represent an advance in the technology available for the analysis of complex mixtures such as essential oils containing terpene-like molecules.

  9. 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.

  10. Photoinduced ethane formation from reaction of ethene with matrix-isolated Ti, V, or Nb atoms.

    PubMed

    Thompson, Matthew G K; Parnis, J Mark

    2005-10-27

    The reactions of matrix-isolated Ti, V, or Nb atoms with ethene (C(2)H(4)) have been studied by FTIR absorption spectroscopy. Under conditions where the ethene dimer forms, metal atoms react with the ethene dimer to yield matrix-isolated ethane (C(2)H(6)) and methane. Under lower ethene concentration conditions ( approximately 1:70 ethene/Ar), hydridic intermediates of the types HMC(2)H(3) and H(2)MC(2)H(2) are also observed, and the relative yield of hydrocarbons is diminished. Reactions of these metals with perdeuterioethene, and equimolar mixtures of C(2)H(4) and C(2)D(4), yield products that are consistent with the production of ethane via a metal atom reaction involving at least two C(2)H(4) molecules. The absence of any other observed products suggests the mechanism also involves production of small, highly symmetric species such as molecular hydrogen and metal carbides. Evidence is presented suggesting that ethane production from the ethene dimer is a general photochemical process for the reaction of excited-state transition-metal atoms with ethene at high concentrations of ethene. PMID:16866395

  11. Matrix Isolation Studies of Carbonic Acid—The Vapor Phase above the β-Polymorph

    PubMed Central

    2013-01-01

    Twenty years ago two different polymorphs of carbonic acid, α- and β-H2CO3, were isolated as thin, crystalline films. They were characterized by infrared and, of late, by Raman spectroscopy. Determination of the crystal structure of these two polymorphs, using cryopowder and thin film X-ray diffraction techniques, has failed so far. Recently, we succeeded in sublimating α-H2CO3 and trapping the vapor phase in a noble gas matrix, which was analyzed by infrared spectroscopy. In the same way we have now investigated the β-polymorph. Unlike α-H2CO3, β-H2CO3 was regarded to decompose upon sublimation. Still, we have succeeded in isolation of undecomposed carbonic acid in the matrix and recondensation after removal of the matrix here. This possibility of sublimation and recondensation cycles of β-H2CO3 adds a new aspect to the chemistry of carbonic acid in astrophysical environments, especially because there is a direct way of β-H2CO3 formation in space, but none for α-H2CO3. Assignments of the FTIR spectra of the isolated molecules unambiguously reveal two different carbonic acid monomer conformers (C2v and Cs). In contrast to the earlier study on α-H2CO3, we do not find evidence for centrosymmetric (C2h) carbonic acid dimers here. This suggests that two monomers are entropically favored at the sublimation temperature of 250 K for β-H2CO3, whereas they are not at the sublimation temperature of 210 K for α-H2CO3. PMID:23631554

  12. Long wavelength photochemistry of ozone and n-butylferrocene: A matrix isolation study

    NASA Astrophysics Data System (ADS)

    Pinelo, Laura F.; Ault, Bruce S.

    2016-07-01

    The photochemical reaction of ozone and n-butylferrocene has been studied using a combination of argon-matrix isolation, infrared spectroscopy, and theoretical calculations. The dark deposition produced a vivid green matrix that, when irradiated with red light, turned a brownish-red color. This green matrix as well as slightly red-shifted O3 infrared absorptions are indicative of the formation an initial charge transfer complex between ozone and n-butylferrocene. The spectral results support the photodissociation of the complexed ozone with red light (λ ≥ 600 nm) producing an oxygen atom, O(3P), and a dioxygen molecule, O2(3Σ). The O(3P) then reacts with n-butylferrocene to form products consisting of an iron atom with a coordinated n-butylcyclopentadienyl or cyclopentadienyl ring and either: (1) a pyran, (2) an aldehyde, or (3) a bidentate cyclic aldehyde with a seven-membered ring including the iron atom. The photochemical products were characterized with FT-IR spectroscopy, 18O-labeled O3 experiments, and DFT calculations using the B3LYP functional with the 6-311++G(d, 2p) basis set. A possible mechanism for the photochemical reaction is discussed.

  13. Long wavelength photochemistry of ozone and n-butylferrocene: A matrix isolation study

    NASA Astrophysics Data System (ADS)

    Pinelo, Laura F.; Ault, Bruce S.

    2016-07-01

    The photochemical reaction of ozone and n-butylferrocene has been studied using a combination of argon-matrix isolation, infrared spectroscopy, and theoretical calculations. The dark deposition produced a vivid green matrix that, when irradiated with red light, turned a brownish-red color. This green matrix as well as slightly red-shifted O3 infrared absorptions are indicative of the formation an initial charge transfer complex between ozone and n-butylferrocene. The spectral results support the photodissociation of the complexed ozone with red light (λ ≥ 600 nm) producing an oxygen atom, O(3P), and a dioxygen molecule, O2(3Σ). The O(3P) then reacts with n-butylferrocene to form products consisting of an iron atom with a coordinated n-butylcyclopentadienyl or cyclopentadienyl ring and either: (1) a pyran, (2) an aldehyde, or (3) a bidentate cyclic aldehyde with a seven-membered ring including the iron atom. The photochemical products were characterized with FT-IR spectroscopy, 18O-labeled O3 experiments, and DFT calculations using the B3LYP functional with the 6-311++G(d, 2p) basis set. A possible mechanism for the photochemical reaction is discussed.

  14. Direct FTIR analysis of isolated trans fatty acids in edible oils using disposable polyethylene film.

    PubMed

    Xu, Lirong; Zhu, Xufei; Chen, Xiumei; Sun, Daijun; Yu, Xiuzhu

    2015-10-15

    A new transmission-based Fourier transform infrared (FTIR) spectroscopy method has been developed to determine trans fatty acids (TFA) content in edible oils using disposable polyethylene (PE) film as a spectral acquisition accessory. Calibration standards were devised by gravimetrically adding TFA to TFA-free oil. The response was measured at 990-945 cm(-1) against the baseline. A linear relationship between the areas in the spectral regions 1670-1625 cm(-1) and 990-945 cm(-1) in TFA-free oil samples was established to compensate for interference due to underlying triacylglycerol absorptions in the trans measurement region (990-945 cm(-1)). Subsequently, the area measured at 990-945 cm(-1) was corrected for interference, using the linear equation obtained, to determine TFA content. Results indicated that the PE film-based FTIR method for analyzing TFA content in edible oils was simple and rapid, and could be used effectively as an alternative to gas chromatography and mass spectrometry methods. PMID:25952899

  15. Synchronized flash photolysis and pulse deposition in matrix isolation experiments

    NASA Technical Reports Server (NTRS)

    Allamandola, Louis J.; Lucas, Donald; Pimentel, George C.

    1978-01-01

    An apparatus is described which permits flash photolysis of a pulse-deposited gas mixture in a matrix isolation experiment. This technique obviates the limitations of in situ photolysis imposed by the cage effect and by secondary photolysis. The matrix is deposited in pulses at 30-s intervals and photolyzed sequentially by four synchronized flashlamps approximately 1 ms before the pulse strikes the cold surface. Pulsed deposition maintains adequate isolation and causes line narrowing, which enhances spectral sensitivity. The efficacy of flash photolysis combined with pulsed deposition for producing and trapping transient species was demonstrated by infrated detection of CF3 (from photolysis of CF3I/Ar mixtures) and of ClCO (from photolysis of Cl2/CO/Ar mixtures). The apparatus was used to study the photolytic decomposition of gaseous tricarbonylironcyclobutadiene, C4H4Fe(CO)3. The results indicate that the primary photolytic step is not elimination of C4H4, as suggested earlier, but rather of CO.

  16. Matrix isolation spectroscopy and the stability of polycyclic aromatics in coal ash: Final report

    SciTech Connect

    Mamantov, G.; Wehry, R.L.

    1987-06-01

    Matrix Isolation Spectroscopy (MIS) overcomes some limitations of conventional molecular fluorescence and infrared (IR) spectroscopies by producing spectra having perhaps 10 times narrower spectral peaks. Analyte molecules are prevented from interacting with each other (or any other foreign molecules) because they are surrounded by an inert solid matrix (e.g., N/sub 2/, Ar, Ne, or Kr) at temperatures <20 K. For IR applications, such matrices exhibit no spectral interferences (phonon peaks occur at <85 cm/sup -1/). When interfaced with conventional gas chromatography (GC), MIS can usually resolve coeluting compounds in complex organic mixtures and is particularly effective for analysis of polycyclic aromatic compounds (PAC). Often, pretreatment is not necessary if there are <10 different compounds in the sample. Owing to the low energy throughput of MIS, combining with dispersive IR is not an effective technique, whereas combining with Fourier-transform infrared (FTIR) and ultraviolet (uv)-visible fluorescence is. Also, matrix-isolation (MI) combinations with other methods, such as electron paramagnetic resonance (EPR), Raman spectroscopy, secondary ion mass spectrometry (SIMS), and photoacoustic spectroscopy (PAS), may be useful. Laser excitation provides a sensitivity of <1 mg/kg. Resolution can be improved using a monochromatic laser, a polarized excitation source and polarized emitted fluorescence, and measuring fluorescence decay time. A separate study showed that PAC are photochemically stabilized in coal ash because of its carbonaceous matter (pie-pie bonding and porosity effect). Nonphotochemical degradation (generally oxidation) occurs for specific PAC (especially those containing a benzylic C-atom, e.g., fluorene).

  17. The optical spectra of matrix-isolated Znn (n <= 6)

    NASA Astrophysics Data System (ADS)

    Schroeder, W.; Wiggenhauser, H.; Schrittenlacher, W.; Kolb, D. M.

    1987-02-01

    The optical properties of small Zn clusters, especially of Zn2 and Zn3, isolated in neon have been studied over a wide photon energy range by absorption, emission, and photoelectron spectroscopy. By employing emission yield spectroscopy the optical transitions of the dimer and the trimer could be unequivocally distinguished from those of higher clusters in the matrix. For Zn2, the experimental data compare reasonably well with calculations found in the literature. However, the ground state, which is usually calculated to be nonbinding, is found to be bound. The main absorption bands of at least three more Zn clusters, tentatively assigned to Zn4-Zn6, have been derived from the concomitant growth of bands in a systematic concentration study.

  18. Matrix isolation investigation of the ozonolysis of propene

    NASA Astrophysics Data System (ADS)

    Coleman, Bridgett E.; Ault, Bruce S.

    2010-07-01

    The matrix isolation technique, combined with infrared spectroscopy and merged jet deposition of ozone with propene led to the observation of "later", more stable products of this ozonolysis reaction. The observed products, specifically formaldehyde and acetaldehyde, are precisely the products predicted by the Criegee mechanism, formed by the two fragmentation pathways from the initial primary ozonide. Hence, the merged jet results strongly support the Criegee mechanism. In contrast, twin jet codeposition experiments followed by annealing led to no visible changes in the spectra. Subsequent irradiation of these twin jet matrices involving ozone with light of λ ⩾ 220 nm led to O atom production and subsequent reaction with propene. Multiple products were observed in these photochemical experiments. Extensive 18O isotopic labeling experiments, comparisons with literature spectra, and detailed theoretical calculations at the B3LYP/6-311++G(d,2p) level provided important supporting data.

  19. Matrix isolation apparatus with extended sample collection capability

    DOEpatents

    Reedy, Gerald T.

    1987-01-01

    A gas-sample collection device provides for the matrix isolation of increased amounts of a sample material for spectrographic analysis from a gas chromatographic separation. The device includes an evacuated sample collection chamber containing a disc-like specular carousel having a generally circular lateral surface upon which the sample is deposited in an inert gas matrix for infrared (IR) spectral analysis. The evacuated sample chamber is mounted in a fixed manner and is coupled to and supports a rotating cryostatic coupler which, in turn, supports the specular carousel within the collection chamber. A rotational drive system connected to the cryostatic coupler provides for its rotational displacement as well as that of the sample collecting carousel. In addition, rotation of the cryostatic coupler effects vertical displacement of the carousel to permit the collection of an extended sample band in a helical configuration on the entire lateral surface of the carousel. The various components of the carousel's angular/linear displacement drive system are located exterior to the cryostatic coupler for easy access and improved operation. The cryostatic coupler includes a 360.degree. rotary union assembly for permitting the delivery of a high pressure working fluid to the cryostatic coupler in a continuous flow manner for maintaining the specular carousel at a low temperature, e.g., 10.degree.-20.degree. K., for improved uninterrupted gas sample collection and analysis.

  20. Device for collecting and analyzing matrix-isolated samples

    DOEpatents

    Reedy, Gerald T.

    1979-01-01

    A gas-sample collection device is disclosed for matrix isolation of individual gas bands from a gas chromatographic separation and for presenting these distinct samples for spectrometric examination. The device includes a vacuum chamber containing a rotatably supported, specular carrousel having a number of external, reflecting surfaces around its axis of rotation for holding samples. A gas inlet is provided for depositing sample and matrix material on the individual reflecting surfaces maintained at a sufficiently low temperature to cause solidification. Two optical windows or lenses are installed in the vacuum chamber walls for transmitting a beam of electromagnetic radiation, for instance infrared light, through a selected sample. Positioned within the chamber are two concave mirrors, the first aligned to receive the light beam from one of the lenses and focus it to the sample on one of the reflecting surfaces of the carrousel. The second mirror is aligned to receive reflected light from that carrousel surface and to focus it outwardly through the second lens. The light beam transmitted from the sample is received by a spectrometer for determining absorption spectra.

  1. Aqueous hydrogen bonding probed with polarization and matrix isolation spectroscopy

    NASA Astrophysics Data System (ADS)

    Shultz, Mary Jane; Bisson, Patrick; Buch, Victoria; Groenzin, Henning; Li, Irene

    2010-05-01

    A major challenge in hydrogen-bond research is interpreting the vibrational spectrum of water, arguably the most fundamental hydrogen bonding system. This challenge remains despite over a half century of progress in vibrational spectroscopy, largely due to a combination of the huge oscillator strength and the enormous width of the hydrogen-bond region. Lack of assignment of the resonances in the hydrogen-bond region hinders investigation of interactions between water and solutes. This lack-of-interpretation issue is an even more significant problem for studies of the aqueous interface. Numerous solutes are known to have an effect, some very dramatic, on the shape of the surface spectrum. These effects, however, are but tantalizing teasers because lack of interpretation means that the changes cannot be used to diagnose the effect of solutes or impinging gas-phase molecules on the surface. In the reported work two techniques are used to probe the origin of vibrational resonances in the H-bonded region: the surface sensitive technique sum frequency generation (SFG) and room-temperature matrix isolation spectroscopy (RT-MIS). A polarization technique called polarization angle null (PAN) has been developed that extends SFG and enables identification of resonances. The result of applying PAN-SFG to single crystal, I h ice is identification of at least nine underlying resonances and assignment of two of these. One resonance is correlated with the crystal temperature and is a sensitive probe for interactions that disrupt long range order on the surface - it is a morphology reporter. The second is associated with weakly bonded, double-donor water molecules. This resonance is sensitive to interaction of hydrogen bond donors, i.e. acids, with the surface. Both modes are more correctly pictured as collective modes. These two assignments are the first definitive assignments in the hydrogen-bond region for the aqueous surface. The effect of salts on the vibrational spectrum of

  2. A combined matrix isolation spectroscopy and cryosolid positron moderation apparatus

    SciTech Connect

    Molek, Christopher D.; Michael Lindsay, C.; Fajardo, Mario E.

    2013-03-15

    We describe the design, construction, and operation of a novel apparatus for investigating efficiency improvements in thin-film cryogenic solid positron moderators. We report results from solid neon, argon, krypton, and xenon positron moderators which illustrate the capabilities and limitations of our apparatus. We integrate a matrix isolation spectroscopy diagnostic within a reflection-geometry positron moderation system. We report the optical thickness, impurity content, and impurity trapping site structures within our moderators determined from infrared absorption spectra. We use a retarding potential analyzer to modulate the flow of slow positrons, and report positron currents vs. retarding potential for the different moderators. We identify vacuum ultraviolet emissions from irradiated Ne moderators as the source of spurious signals in our channel electron multiplier slow positron detection channel. Our design is also unusual in that it employs a sealed radioactive Na-22 positron source which can be translated relative to, and isolated from, the cryogenic moderator deposition substrate. This allows us to separate the influences on moderator efficiency of surface contamination by residual gases from those of accumulated radiation damage.

  3. Force degradation behavior of glucocorticoid deflazacort by UPLC: isolation, identification and characterization of degradant by FTIR, NMR and mass analysis

    PubMed Central

    Deshmukh, Rajesh; Sharma, Lata; Tekade, Muktika; Kesharwani, Prashant; Trivedi, Piyush; Tekade, Rakesh K.

    2016-01-01

    Abstract In this investigation, sensitive and reproducible methods are described for quantitative determination of deflazacort in the presence of its degradation product. The method was based on high performance liquid chromatography of the drug from its degradation product on reverse phase using Acquity UPLC BEH C18 columns (1.7 µm, 2.1 mm × 150 mm) using acetonitrile and water (40:60 V/V) at a flow rate of 0.2 mL/minute in UPLC. UV detection was performed at 240.1 nm. Deflazacort was subjected to oxidative, acid, base, hydrolytic, thermal and photolytic degradation. The drug was found to be stable in water and thermal stress, as well as under neutral stress conditions. However, forced-degradation study performed on deflazacort showed that the drug degraded under alkaline, acid and photolytic stress. The degradation products were well resolved from the main peak, which proved the stability-indicating power of the method. The developed method was validated as per ICH guidelines with respect to accuracy, linearity, limit of detection, limit of quantification, accuracy, precision and robustness, selectivity and specificity. Apart from the aforementioned, the results of the present study also emphasize the importance of isolation characterization and identification of degradant. Hence, an attempt was made to identify the degradants in deflazacort. One of the degradation products of deflazacort was isolated and identified by the FTIR, NMR and LC-MS study.

  4. UV-tunable laser induced phototransformations of matrix isolated anethole

    SciTech Connect

    Krupa, Justyna; Wierzejewska, Maria E-mail: rfausto@ci.uc.pt; Nunes, Cláudio M.; Fausto, Rui E-mail: rfausto@ci.uc.pt

    2014-03-14

    A matrix isolation study of the infrared spectra and structure of anethole (1-methoxy-4-(1-propenyl)benzene) has been carried out, showing the presence of two E conformers (AE1, AE2) of the molecule in the as-deposited matrices. Irradiation using ultraviolet-tunable laser light at 308–307 nm induced conformationally selective phototransformations of these forms into two less stable Z conformers (AZ1, AZ2). The back reactions were also detected upon irradiation at 301 nm. On the whole, the obtained results allow for full assignment of the infrared spectra of all the four experimentally observed anethole isomers and showed that the narrowband UV-induced E-Z photoisomerization is an efficient and selective way to interconvert the two isomers of anethole into each other, with conformational discrimination. Photolysis of anethole was observed as well, with initial methoxyl O–C bond cleavage and formation of CH{sub 3} and p-propenylphenoxy (AR) radicals, followed by radical recombination to form 2-methyl-4-propenyl-2,4-cyclohexadienone, which subsequently undergoes ring-opening generating several conformers of long-chain conjugated ketenes. Interpretation of the experimental observations was supported by density functional theory (B3LYP and B2PLYD) calculations.

  5. The novel acid degradation products of losartan: Isolation and characterization using Q-TOF, 2D-NMR and FTIR.

    PubMed

    Kumar Pandey, Avadhesh; Rapolu, Ravi; Raju, Ch Krishnam; Sasalamari, Gururaj; Kumar Goud, Sanath; Awasthi, Atul; Navalgund, Sameer G; Surendranath, Koduru V

    2016-02-20

    Forced degradation of losartan potassium in acidic condition resulted into three potential unknown impurities. These unknown degradation products marked as LD-I, LD-II and LD-III were analyzed using a new reverse-phase high performance liquid chromatography (HPLC), eluting at 3.63, 3.73 and 3.91 relative retention times with respect to losartan potassium (LOS) peak. All three were isolated from reaction mass using preparative HPLC and their structures were elucidated using LC-MS/MS, multidimensional NMR and FTIR spectroscopic techniques, as 5(2),11(2)-dibutyl-5(4),11(4)-dichloro-1(1)H,5(1)H,7(1)H,11(1)H-1(5,1),7(1,5)-ditetrazola-5,11(1,5)-diimidazola-2,8(1,2),3,9(1,4)-tetrabenzenacyclododecaphane,(Z)-5(2),11(2)-dibutyl-5(4),11(4)-dichloro-1(1)H,5(1)H,7(2)H,11(1)H-1(5,1),7(2,5)-ditetrazola-5,11(1,5)-diimidazola-2,8(1,2),3,9(1,4)-tetrabenzenacyclododecaphane, and 5(2),11(2)-dibutyl-5(4),11(4)-dichloro-1(2)H,5(1)H,7(2)H,11(1)H-1(5,2),7(2,5)-ditetrazola-5,11(1,5)-diimidazola-2,8(1,2),3,9(1,4)-tetrabenzenacyclododecaphane, respectively. To best of our knowledge, all three degradation products are novel impurities which are not discussed at any form of publication yet. PMID:26704631

  6. Isolation and characterization of chicken bile matrix metalloproteinase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian bile is rich in matrix metalloproteinases (MMP), the enzymes that cleave extracellular matrix (ECM) proteins such as collagens and proteoglycans. Changes in bile MMP expression have been correlated with hepatic and gall bladder pathologies but the significance of their expression in normal, he...

  7. Radiation-induced transformations of matrix-isolated formic acid: evidence for the HCOOH → HOCO + H channel.

    PubMed

    Ryazantsev, Sergey V; Feldman, Vladimir I

    2015-11-11

    The effect of X-ray irradiation on the isolated formic acid molecules (HCOOH) in solid noble gas matrices (Xe, Kr, Ar, and Ne) at very low temperatures (6 K) was first studied by FTIR spectroscopy. Carbon oxides (CO and CO2) and hydrocarboxyl radicals (HOCO) have been detected as the principal degradation products. The formation of HOCO radicals represents a primary dissociation channel for formic acid, which was not reported previously under UV photolysis in solids. This reaction can be explained by the involvement of the recombination-induced excited states, which are not populated in photolysis. The effects of the matrix and the absorbed dose on the product formation were studied in detail and possible mechanisms are discussed with particular attention to the difference between radiolysis and UV-photolysis of the matrix-isolated formic acid. The results obtained provide a new insight into the effects of high-energy impact on the simplest carboxylic acid with possible implications to the astrochemical problems, in particular, the prebiotic evolution in the interstellar medium. PMID:26524429

  8. Mössbauer spectroscopy of trimethyl tin halide molecules matrix-isolated in solid rare gas

    NASA Astrophysics Data System (ADS)

    Bukshpan, S.

    1991-02-01

    The study of matrix-isolated (CH 3) 3SnCl, (CH 3) 3SnBr and (CH 3) 3SnI reveals a tetrahedral molecular structure similar to the corresponding phenyl molecules. The results confirm that in the crystalline state of these compounds the tin atom is five-coordinated while in the matrix-isolated state the coordination number is four.

  9. Matrix isolation spectra of metal atoms and ions: Ti, Zr, and Mo in Ar and Kr

    NASA Astrophysics Data System (ADS)

    Steinbrüchel, Christoph; Gruen, Dieter M.

    1981-01-01

    UV-absorption spectra are reported of neutral atoms and ions of Ti, Zr, and Mo in Ar and Kr matrices. The matrix-isolated species are produced by ion bombardment of a bulk metal target. Thermal and photoannealing experiments indicate that sputtered neutral atoms may occupy one or two distinct matrix sites, depending on the system. Sputtered ions, after being neutralized in the matrix, either go preferentially into the higher energy site, i.e., the site whose absorption bands are shifted farther to the blue, when atoms already populate two sites, or they create a new site at higher energy when there is only one site for atoms. Deconvolution of matrix isolation spectra into contributions from individual sites shows that spectra due to atoms in a particular site correspond much better to gas phase spectra than do total matrix isolation spectra. Matrix shifts of atomic absorption bands for both sites can be rationalized using a model by McCarty and Robinson if allowance is made for matrix distortion around solute atoms. The blue, or close-packed, site is found to correspond to a solute atom replacing a single matrix atom without inducing appreciable matrix distortion, whereas the red, or expanded, site requires the cage around a solute atom to be enlarged by a few percent.

  10. Isolation and characterization of chicken bile matrix metalloproteinase

    PubMed Central

    Packialakshmi, B.; Liyanage, R.; Rasaputra, K. S.; Lay, Jackson O.; Rath, N. C.

    2014-01-01

    Avian bile is rich in matrix metalloproteinases (MMP), the enzymes that cleave extracellular matrix proteins such as collagens and proteoglycans. Changes in bile MMP expression have been correlated with hepatic and gall bladder pathologies, but the significance of their expression in normal, healthy bile is not understood. We hypothesized that the MMP in bile may aid the digestion of native collagens that are resistant to conventional gastric proteases. Hence, the objective of this study was to characterize the bile MMP and check its regulation in association with dietary factors. We used substrate zymography, azocoll protease assay, and gelatin affinity chromatography to identify and purify the MMP from chicken bile. Using zymography and SDS PAGE, 5 bands at 70, 64, 58, 50, and 42 kDa were detected. The bands corresponding to 64, 50, and 42 kDa were identified as MMP2 using trypsin in-gel digestion and matrix-assisted laser desorption time-of-flight mass spectrometry and peptide mass fingerprinting. Chickens fed diets containing gelatin supplements showed higher levels of MMP expression in the bile by both azocoll assay and zymography. We conclude that the bile MMP may be associated with the digestion of collagens and other extracellular matrix proteins in avian diets. PMID:24879699

  11. Matrix isolation sublimation: An apparatus for producing cryogenic beams of atoms and molecules

    SciTech Connect

    Sacramento, R. L.; Alves, B. X.; Silva, B. A.; Wolff, W.; Cesar, C. L.; Oliveira, A. N.; Li, M. S.

    2015-07-15

    We describe the apparatus to generate cryogenic beams of atoms and molecules based on matrix isolation sublimation. Isolation matrices of Ne and H{sub 2} are hosts for atomic and molecular species which are sublimated into vacuum at cryogenic temperatures. The resulting cryogenic beams are used for high-resolution laser spectroscopy. The technique also aims at loading atomic and molecular traps.

  12. Photochemistry of matrix-isolated and thin film acid chlorides: Quantum yields and product structures

    SciTech Connect

    Rowland, B.; Hess, W.P.; Winter, P.R.; Ellison, G.B.; Radziszewski, J.G.

    1999-02-18

    Ultraviolet photoexcitation of matrix-isolated CH{sub 3}COCl, CH{sub 3}CH{sub 2}COCl, and CH{sub 3}CH{sub 2}CH{sub 2}CH{sub 2}COCl produces HCl{center_dot}CH{sub 2}{double_bond}C{double_bond}O, HCl{center_dot}CH{sub 3}CHC{double_bond}C{double_bond}O, and HCl{center_dot}CH{sub 3}CH{sub 2}CH{sub 2}CHC{double_bond}C{double_bond}O complexes. The authors report precursor and matrix dependent reaction quantum yields. Quantum yield values decrease with increasing alkyl chain length due to a reduced number of {alpha} H-atoms available for the elimination reaction and steric considerations. The authors found quantum yields in neat matrixes to be roughly half that in argon or xenon matrixes and assign structures for HCL and ketene complexes in argon and xenon matrixes by comparing IR spectra ab initio electronic structure calculations. In argon matrixes, the product complex HCl frequently is strongly shifted whereas the ketene remains unshifted with respect to matrix-isolated ketene. In xenon matrixes, HCl{center_dot}ketene complexes display absorption bands indicative of two distinct structures. Differences between HCl{center_dot}ketene structures in argon and xenon matrixes are attributed to size differences of the matrix lattice.

  13. Isolation, Characterization, and Aggregation of a Structured Bacterial Matrix Precursor*

    PubMed Central

    Chai, Liraz; Romero, Diego; Kayatekin, Can; Akabayov, Barak; Vlamakis, Hera; Losick, Richard; Kolter, Roberto

    2013-01-01

    Biofilms are surface-associated groups of microbial cells that are embedded in an extracellular matrix (ECM). The ECM is a network of biopolymers, mainly polysaccharides, proteins, and nucleic acids. ECM proteins serve a variety of structural roles and often form amyloid-like fibers. Despite the extensive study of the formation of amyloid fibers from their constituent subunits in humans, much less is known about the assembly of bacterial functional amyloid-like precursors into fibers. Using dynamic light scattering, atomic force microscopy, circular dichroism, and infrared spectroscopy, we show that our unique purification method of a Bacillus subtilis major matrix protein component results in stable oligomers that retain their native α-helical structure. The stability of these oligomers enabled us to control the external conditions that triggered their aggregation. In particular, we show that stretched fibers are formed on a hydrophobic surface, whereas plaque-like aggregates are formed in solution under acidic pH conditions. TasA is also shown to change conformation upon aggregation and gain some β-sheet structure. Our studies of the aggregation of a bacterial matrix protein from its subunits shed new light on assembly processes of the ECM within bacterial biofilms. PMID:23632024

  14. The Vibrational Structure of OH Radical and OH-H_2O Complex: a Matrix Isolation Study

    NASA Astrophysics Data System (ADS)

    Joshi, Prasad R.; Krim, Lahouari

    2010-06-01

    Hydroxyl radical, 'the detergent of atmosphere', the title is acquired due to capability of transformation of trace component present in atmosphere mainly troposphere into water soluble forms and also plays vital role in chemistry of the interstellar medium. The infrared spectra of OH radical isolated in solid neon have been investigated by Fourier Transform infrared spectroscopy (FTIR). OH monomer was prepared by microwave discharge of a mixture of water and neon gas at different concentrations prior to deposition on the cold mirror at 5 K. The microwave discharge of H_2O/Ne system is remarkable due to its propensity to form OH radical and other species like H_2, HO_2, OH-HO_2, OH-H_2O and (OH)_n-H_2O and IR spectroscopy reveals a variety of phenomena far from being fully understood. OH concentration studies, D/H isotopic substitution, and subsequent annealing leads to the characterization of the different species trapped in the neon matrix. All vibrationnal mode of OH-H_2O complex have been detected. The presence of species such as H_2 and HO_2 after matrix deposition led us to carry subsequent UV photolysis of our samples where the complex OH-H_2O may also be formed by following reaction: HO_2-H_2 + hν → OH-H_2O

  15. FT-IR and FT-Raman characterization of non-cellulosic polysaccharides fractions isolated from plant cell wall.

    PubMed

    Chylińska, Monika; Szymańska-Chargot, Monika; Zdunek, Artur

    2016-12-10

    The purpose of this work was to reveal the structural changes of cell wall polysaccharides' fractions during tomato fruit development by analysis of spectral data. Mature green and red ripe tomato fruit were taken into consideration. The FT-IR spectra of water soluble pectin (WSP), imidazole soluble pectin (ISP) and diluted alkali soluble pectin (DASP) contained bands typical for pectins. Whereas for KOH fraction spectra bands typical for hemicelluloses were present. The FT-IR spectra showed the drop down of esterification degree of WSP and ISP polysaccharides during maturation. The changes in polysaccharides structure revealed by spectra were the most visible in the case of pectic polysaccharides. The WSP and DASP fraction pectins molecules length were shortened during tomato maturation and ripening. Whereas the ISP fraction spectra analysis showed that this fraction contained rhamnogalacturonan I, but also for red ripe was rich in pectic galactan comparing with ISP fraction from mature green. PMID:27577895

  16. Matrix Production, Pigment Synthesis, and Sporulation in a Marine Isolated Strain of Bacillus pumilus

    PubMed Central

    Di Luccia, Blanda; Riccio, Antonio; Vanacore, Adele; Baccigalupi, Loredana; Molinaro, Antonio; Ricca, Ezio

    2015-01-01

    The ability to produce an extracellular matrix and form multicellular communities is an adaptive behavior shared by many bacteria. In Bacillus subtilis, the model system for spore-forming bacteria, matrix production is one of the possible differentiation pathways that a cell can follow when vegetative growth is no longer feasible. While in B. subtilis the genetic system controlling matrix production has been studied in detail, it is still unclear whether other spore formers utilize similar mechanisms. We report that SF214, a pigmented strain of Bacillus pumilus isolated from the marine environment, can produce an extracellular matrix relying on orthologs of many of the genes known to be important for matrix synthesis in B. subtilis. We also report a characterization of the carbohydrates forming the extracellular matrix of strain SF214. The isolation and characterization of mutants altered in matrix synthesis, pigmentation, and spore formation suggest that in strain SF214 the three processes are strictly interconnected and regulated by a common molecular mechanism. PMID:26506360

  17. APPLICATION OF MATRIX ISOLATION INFRARED SPECTROSCOPY TO ANALYSIS FOR POLYNUCLEAR AROMATIC HYDROCARBONS IN ENVIRONMENTAL SAMPLES

    EPA Science Inventory

    Gas chromatography combined with matrix isolation infrared spectroscopy (GC/MI-IR) enables identification and quantification of components of complex mixtures by infrared spectroscopy at levels of a few nanograms. These levels are several orders of magnitude lower than those achi...

  18. Fluorescence spectroscopy in the nanosecond range for matrix-isolated Cu atoms and dimers

    NASA Astrophysics Data System (ADS)

    Wiggenhauser, H.; Kolb, D. M.; Rotermund, H. H.; Schrittenlacher, W.; Schroeder, W.

    1985-11-01

    Synchrotron radiation in the single-bunch mode was employed to study time-resolved emission from Cu atoms and dimers isolated in a Ne matrix. The decay time of the matrix-related emission at 3.5 eV for Cu in Ne after excitation of the 4s → 4p resonance transition was determined as 6.9±0.3 ns, while excitation into higher-lying 3d → 4p transitions resulted in a much slower decay of the 3.5 eV emission. From analysis of rise and decay times, a detailed diagram for energy dissipation in matrix-isolated Cu atoms has been derived. The B → X (Σ u → Σ g) emission of Cu 2 in Ne has a first-order decay time of about 10 ns.

  19. Production and characterization of para-hydrogen gas for matrix isolation infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Sundararajan, K.; Sankaran, K.; Ramanathan, N.; Gopi, R.

    2016-08-01

    Normal hydrogen (n-H2) has 3:1 ortho/para ratio and the production of enriched para-hydrogen (p-H2) from normal hydrogen is useful for many applications including matrix isolation experiments. In this paper, we describe the design, development and fabrication of the ortho-para converter that is capable of producing enriched p-H2. The p-H2 thus produced was probed using infrared and Raman techniques. Using infrared measurement, the thickness and the purity of the p-H2 matrix were determined. The purity of p-H2 was determined to be >99%. Matrix isolation infrared spectra of trimethylphosphate (TMP) and acetylene (C2H2) were studied in p-H2 and n-H2 matrices and the results were compared with the conventional inert matrices.

  20. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analyses of mineral and organic matrix during heating of mother of pearl (nacre) from the shell of the mollusc Pinctada maxima.

    PubMed

    Balmain, J; Hannoyer, B; Lopez, E

    1999-01-01

    Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction patterns were used to analyze the mineral structure and organic matrix composition and thermal behavior of the internal nacreous layer (mother of pearl or nacre) of the shell of the giant oyster Pinctada maxima. Nacre is a natural biomaterial with osteogenic properties. The mineral of nacre is calcium carbonate crystallized as aragonite and it is highly crystallized. The FT-IR spectra showed amide, amine, and carboxylic acid groups in the organic matrix of the whole (organic and mineral) nacreous layer, with the HCO(-)(3) groups possibly at the organic-mineral interface. The insoluble organic matrix remaining after decalcification contained amide, amine, and carboxylic groups. The heated aragonite mineral structure of nacre underwent two transformations (X-ray diffraction), aragonite to calcite at 300-400 degrees C, and calcite to calcium oxide (CaO) at 500-600 degrees C. The organic matrix of nacre was destroyed around 550-600 degrees C, the same temperature as the calcite to CaO transformation, revealing the great thermal stability of the organic matrix and the organic-mineral bonding. This could be an useful feature for the in vivo use of this natural biomaterial as an implant. PMID:10490692

  1. Incorporation of Mn into the vacant T-atom sites of a BEA zeolite as isolated, mononuclear Mn: FTIR, XPS, EPR and DR UV-Vis studies.

    PubMed

    Baran, R; Valentin, L; Dzwigaj, S

    2016-04-28

    A MnSiBEA zeolite has been prepared via a two-step postsynthesis procedure which consisted, in the first step, of the treatment of a tetraethylammonium BEA zeolite with nitric acid for the formation of vacant T-atom sites and then, in the second step, of the incorporation of Mn ions into the framework, resulting in a SiBEA zeolite, through their reaction with the silanol group of the vacant T-atom sites. The incorporation of Mn ions into the framework of the SiBEA zeolite has been evidenced using XRD. The formation of isolated mononuclear Mn(ii) and Mn(iii) in a MnSiBEA zeolite has been shown using FTIR, diffuse reflectance UV-Vis, EPR and XPS. The acidic properties of the mononuclear manganese species have been investigated via FTIR spectroscopy using pyridine as the probe molecule. The changes in the oxidation state of the Mn species under various treatments have been proven using EPR. PMID:27067795

  2. Monitoring UVR induced damage in single cells and isolated nuclei using SR-FTIR microspectroscopy and 3D confocal Raman imaging.

    PubMed

    Lipiec, Ewelina; Bambery, Keith R; Heraud, Philip; Kwiatek, Wojciech M; McNaughton, Don; Tobin, Mark J; Vogel, Christian; Wood, Bayden R

    2014-09-01

    SR-FTIR in combination with Principal Component Analysis (PCA) was applied to investigate macromolecular changes in a population of melanocytes and their extracted nuclei induced by environmentally relevant fluxes of UVR (Ultraviolet Radiation). Living cells and isolated cellular nuclei were investigated post-irradiation for three different irradiation dosages (130, 1505, 15,052 Jm(-2) UVR, weighted) after either 24 or 48 hours of incubation. DNA conformational changes were observed in cells exposed to an artificial UVR solar-simulator source as evidenced by a shift in the DNA asymmetric phosphodiester vibration from 1236 cm(-1) to 1242 cm(-1) in the case of the exposed cells and from 1225 cm(-1) to 1242 cm(-1) for irradiated nuclei. PCA Scores plots revealed distinct clustering of spectra from irradiated cells and nuclei from non-irradiated controls in response to the range of applied UVR radiation doses. 3D Raman confocal imaging in combination with k-means cluster analysis was applied to study the effect of the UVR radiation exposure on cellular nuclei. Chemical changes associated with apoptosis were detected and included intra-nuclear lipid deposition along with chromatin condensation. The results reported here demonstrate the utility of SR-FTIR and Raman spectroscopy to probe in situ DNA damage in cell nuclei resulting from UVR exposure. These results are in agreement with the increasing body of evidence that lipid accumulation is a characteristic of aggressive cancer cells, and are involved in the production of membranes for rapid cell proliferation. PMID:24995477

  3. Isolation and culture of human trabecular meshwork cells by extracellular matrix digestion.

    PubMed

    Stamer, W D; Seftor, R E; Williams, S K; Samaha, H A; Snyder, R W

    1995-07-01

    Like corneal endothelial cells, human trabecular meshwork cells are believed to be of neural crest origin, but demonstrate physiological properties and an antithrombogenic surface similar to vascular endothelial cells. One current method for isolating trabecular meshwork cells utilizes the motile nature of these cells to migrate away from a trabecular meshwork explant in culture to more distal regions of the culture dish. This 'outgrowth' technique is limited in practice by the relatively small number of cells that migrate per explant per unit time, thus hindering the ability to gather sufficient numbers of cells for comprehensive experimentation. For this reason, we have modified an extracellular matrix digestion technique in current use for the isolation of microvascular endothelial cells to isolate human trabecular meshwork cells. This procedure is both efficient and rapid for isolating large numbers of trabecular meshwork cells and results in the availability of trabecular meshwork cells in sufficient quantities for subsequent experimentation. PMID:7587308

  4. Isolation of a crystal matrix protein associated with calcium oxalate precipitation in vacuoles of specialized cells.

    PubMed

    Li, Xingxiang; Zhang, Dianzhong; Lynch-Holm, Valerie J; Okita, Thomas W; Franceschi, Vincent R

    2003-10-01

    The formation of calcium (Ca) oxalate crystals is considered to be a high-capacity mechanism for regulating Ca in many plants. Ca oxalate precipitation is not a stochastic process, suggesting the involvement of specific biochemical and cellular mechanisms. Microautoradiography of water lettuce (Pistia stratiotes) tissue exposed to 3H-glutamate showed incorporation into developing crystals, indicating potential acidic proteins associated with the crystals. Dissolution of crystals leaves behind a crystal-shaped matrix "ghost" that is capable of precipitation of Ca oxalate in the original crystal morphology. To assess whether this matrix has a protein component, purified crystals were isolated and analyzed for internal protein. Polyacrylamide gel electrophoresis revealed the presence of one major polypeptide of about 55 kD and two minor species of 60 and 63 kD. Amino acid analysis indicates the matrix protein is relatively high in acidic amino acids, a feature consistent with its solubility in formic acid but not at neutral pH. 45Ca-binding assays demonstrated the matrix protein has a strong affinity for Ca. Immunocytochemical localization using antibody raised to the isolated protein showed that the matrix protein is specific to crystal-forming cells. Within the vacuole, the surface and internal structures of two morphologically distinct Ca oxalate crystals, raphide and druse, were labeled by the antimatrix protein serum, as were the surfaces of isolated crystals. These results demonstrate that a specific Ca-binding protein exists as an integral component of Ca oxalate crystals, which holds important implications with respect to regulation of crystal formation. PMID:14555781

  5. Isolation of Human Mesenchymal Stem Cells and their Cultivation on the Porous Bone Matrix

    PubMed Central

    Rodríguez-Fuentes, Nayeli; Reynoso-Ducoing, Olivia; Rodríguez-Hernández, Ana; Ambrosio-Hernández, Javier R.; Piña-Barba, Maria C.; Zepeda-Rodríguez, Armando; Cerbón-Cervantes, Marco A.; Tapia-Ramírez, José; Alcantara-Quintana, Luz E.

    2015-01-01

    Mesenchymal stem cells (MSCs) have a differentiation potential towards osteoblastic lineage when they are stimulated with soluble factors or specific biomaterials. This work presents a novel option for the delivery of MSCs from human amniotic membrane (AM-hMSCs) that employs bovine bone matrix Nukbone (NKB) as a scaffold. Thus, the application of MSCs in repair and tissue regeneration processes depends principally on the efficient implementation of the techniques for placing these cells in a host tissue. For this reason, the design of biomaterials and cellular scaffolds has gained importance in recent years because the topographical characteristics of the selected scaffold must ensure adhesion, proliferation and differentiation into the desired cell lineage in the microenvironment of the injured tissue. This option for the delivery of MSCs from human amniotic membrane (AM-hMSCs) employs bovine bone matrix as a cellular scaffold and is an efficient culture technique because the cells respond to the topographic characteristics of the bovine bone matrix Nukbone (NKB), i.e., spreading on the surface, macroporous covering and colonizing the depth of the biomaterial, after the cell isolation process. We present the procedure for isolating and culturing MSCs on a bovine matrix. PMID:25742362

  6. The isolation of cell derived extracellular matrix constructs using sacrificial open-cell foams.

    PubMed

    Wolchok, Jeffrey C; Tresco, Patrick A

    2010-12-01

    Extracellular matrix derived from human and animal tissues is being used to repair and reconstruct a variety of tissues clinically. The utility of such constructs is limited by the geometry, composition and constitutive properties of the tissue or organ from which the ECM is harvested. To address this limitation, we have developed an approach to isolate extracellular matrix in bulk from populations of living cells grown in culture on three-dimensional substrates. Human biopsy derived fibroblasts were seeded within open-cell foams and cultured in-vitro for periods up to three weeks, after which the synthetic component was removed by incubation in a water miscible solvent. After several wash steps and lyophilization, a white, lacy, multi-molecular construct was isolated. Tandem mass spectroscopy showed that it contained 22 extracellular matrix constituents, including such proteins and proteoglycans as collagen type I and type III, fibronectin, transforming growth factor beta, decorin and biglycan among others. On average 47 mg of construct was isolated for each gram of synthetic substrate initially seeded with cells. The biomaterial harvested from human tracheal fibroblasts had an elastic modulus (250 kPa) and a composition similar to that of human vocal fold tissue, and supported reseeding with human tracheal derived fibroblasts. An important finding was that the approach was useful in isolating ECM from a variety of cell lineages and developmental stages including skin fibroblasts, brain derived astrocytes and mesenchymal stem cells. The results, together with the archival literature, suggest that the approach can be used to produce a range of cell derived constructs with unique physical and chemical attributes for a variety of research and medical applications. PMID:20950855

  7. Carbonate measurements in PM10 near the marble quarries of Carrara (Italy) by infrared spectroscopy (FT-IR) and source apportionment by positive matrix factorization (PMF)

    NASA Astrophysics Data System (ADS)

    Cuccia, E.; Piazzalunga, A.; Bernardoni, V.; Brambilla, L.; Fermo, P.; Massabò, D.; Molteni, U.; Prati, P.; Valli, G.; Vecchi, R.

    2011-11-01

    The concentration of carbonates in atmospheric Particulate Matter (PM) is usually quite low. The surroundings of marble quarries are peculiar sites where the impact of carbonates in PM levels can be significant. We present here the results of a PM10 sampling campaign performed in Carrara (Italy). The town lies between the famous marble quarries and the harbour: about 1000 trucks per day transport marble blocks and debris from the quarries to the harbour passing through the town centre. PM10 was collected on daily basis on PTFE filters analyzed by Energy-Dispersive X-Ray Fluorescence (ED-XRF) and Ion-Chromatography (IC). Carbonate concentration was measured by a non-destructive Infrared Spectroscopy analysis (FT-IR). Time series of elemental (Na-Pb by ED-XRF), ionic (SO 42-, NH 4+ by ion-chromatography) and carbonate (by FT-IR) concentration values were merged in a unique data set and a PMF analysis singled out the major PM10 sources in the area. Marble transportation turned out to be the major pollution source in the town accounting to PM10 for about 36%; this corresponded to a CaCO 3 average level of about 8 μg m -3 during working days. The FT-IR analysis was a crucial part of the work and an ad-hoc analytical procedure was specifically set up, calibrated, and tested as described in the text.

  8. Patch Size, Functional Isolation, Visibility and Matrix Permeability Influences Neotropical Primate Occurrence within Highly Fragmented Landscapes

    PubMed Central

    da Silva, Lucas Goulart; Ribeiro, Milton Cezar; Hasui, Érica; da Costa, Carla Aparecida; da Cunha, Rogério Grassetto Teixeira

    2015-01-01

    Forest fragmentation and habitat loss are among the major current extinction causes. Remaining fragments are mostly small, isolated and showing poor quality. Being primarily arboreal, Neotropical primates are generally sensitive to fragmentation effects. Furthermore, primates are involved in complex ecological process. Thus, landscape changes that negatively interfere with primate population dynamic affect the structure, composition, and ultimately the viability of the whole community. We evaluated if fragment size, isolation and visibility and matrix permeability are important for explaining the occurrence of three Neotropical primate species. Employing playback, we verified the presence of Callicebus nigrifrons, Callithrix aurita and Sapajus nigritus at 45 forest fragments around the municipality of Alfenas, Brazil. We classified the landscape and evaluated the metrics through predictive models of occurrence. We selected the best models through Akaike Selection Criterion. Aiming at validating our results, we applied the plausible models to another region (20 fragments at the neighboring municipality of Poço Fundo, Brazil). Twelve models were plausible, and three were validated, two for Sapajus nigritus (Area and Area+Visibility) and one for Callicebus nigrifrons (Area+Matrix). Our results reinforce the contribution of fragment size to maintain biodiversity within highly degraded habitats. At the same time, they stress the importance of including novel, biologically relevant metrics in landscape studies, such as visibility and matrix permeability, which can provide invaluable help for similar studies in the future and on conservation practices in the long run. PMID:25658108

  9. Intense, hyperthermal source of organic radicals for matrix-isolation spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Xu; Friderichsen, Anders V.; Nandi, Sreela; Ellison, G. Barney; David, Donald E.; McKinnon, J. Thomas; Lindeman, Theodore G.; Dayton, David C.; Nimlos, Mark R.

    2003-06-01

    We have incorporated a pulsed, hyperthermal nozzle with a cryostat to study the matrix-isolated infrared spectroscopy of organic radicals. The radicals are produced by pyrolysis in a heated, narrow-bore (1-mm-diam) SiC tube and then expanded into the cryostat vacuum chamber. The combination of high nozzle temperature (up to 1800 K) and near-sonic flow velocities (on the order of 104cm s-1) through the length of the 2 cm tube allows for high yield of radicals (approximately 1013 radicals pulse-1) and low residence time (on the order of 10 μs) in the nozzle. We have used this hyperthermal nozzle/matrix isolation experiment to observe the IR spectra of complex radicals such as allyl radical (CH2CHCH2), phenyl radical (C6H5), and methylperoxyl radical (CH3OO). IR spectra of samples produced with a hyperthermal nozzle are remarkably clean and relatively free of interfering radical chemistry. By monitoring the unimolecular thermal decomposition of allyl ethyl ether in the nozzle using matrix IR spectroscopy, we have derived the residence time (τnozzle) of the gas pulse in the nozzle to be around 30 μs.

  10. Structural and spectroscopic study of a pectin isolated from citrus peel by using FTIR and FT-Raman spectra and DFT calculations

    NASA Astrophysics Data System (ADS)

    Bichara, Laura C.; Alvarez, Patricia E.; Fiori Bimbi, María V.; Vaca, Hugo; Gervasi, Claudio; Brandán, Silvia Antonia

    2016-05-01

    In this work, pectin isolated from citrus peel with a degree of esterification of 76% was characterized by Fourier Transform Infrared (FTIR) and Fourier Transform Raman (FT-Raman) spectroscopies. Structural studies were carried out taking into account their partial degree of esterification and considering the polygalacturonic acid chain as formed by two different subunits, one with both COOH and COOsbnd CH3 groups (Ac) and the other one as constituted by two subunits with two COOsbnd CH3 groups (Es). Their structural properties, harmonic frequencies, force fields and force constants in gas and aqueous solution phases were calculated by using the hybrid B3LYP/6-31G∗ method. Then, their complete vibrational analyses were performed by using the IR and Raman spectra accomplished with the scaled quantum mechanical (SQM) methodology. Reactivities and behaviors in both media were predicted for Ac and Es by using natural bond orbital (NBO), atoms in molecules (AIM), and frontier orbitals calculations. We report for first time the complete assignments of those two different units of polygalacturonic acid chain which are the 132 normal vibration modes of Ac and the 141 normal vibration modes of Es, combining the normal internal coordinates with the SQM methodology. In addition, three subunits were also studied. Reasonable correlations between the experimental and theoretical spectra were obtained. Thus, this work would allow the quick identification of pectin by using infrared and Raman spectroscopies and also provides new insight into the interactions that exist between subunits of a large pectin chain.

  11. Polyfluorides and Neat Fluorine as Host Material in Matrix-Isolation Experiments.

    PubMed

    Brosi, Felix; Vent-Schmidt, Thomas; Kieninger, Stefanie; Schlöder, Tobias; Beckers, Helmut; Riedel, Sebastian

    2015-11-01

    The use of neat fluorine in matrix isolation is reported, as well as the formation of polyfluoride monoanions under cryogenic conditions. Purification procedures and spectroscopic data of fluorine are described, and matrix shifts of selected molecules and impurities in solid fluorine are compared to those of common matrix gases (Ar, Kr, N2 , Ne). The reaction of neat fluorine and IR-laser ablated metal atoms to yield fluorides of chromium (CrF5 ), palladium (PdF2 ), gold (AuF5 ), and praseodymium (PrF4 ) has been investigated. The fluorides have been characterized in solid fluorine by IR spectroscopy at 5 K. Also the fluorination of Kr and the photo-dismutation of XeO4 have been studied by using IR spectroscopy in neat fluorine. Formation of the [F5 ](-) ion was obtained by IR-laser ablation of platinum in the presence of fluorine and proven in a Ne matrix at 5 K by two characteristic vibrational bands of [F5 ](-) at $\\tilde \

  12. Characterization of a 1:1 Methanol-Benzene Complex Using Matrix Isolation Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Amicangelo, Jay C.; Romano, Natalie C.; Demay, Geoffrey R.

    2013-06-01

    Matrix isolation infrared spectroscopy was used to characterize a 1:1 complex of methanol (CH_{3}OH) with benzene (C_{6}H_{6}). Co-deposition experiments with CH_{3}OH and C_{6}H_{6} were performed at 17 - 20 K using nitrogen and argon as the matrix gases. New infrared bands attributable to the CH_{3}OH-C_{6}H_{6} complex were observed near the O-H and C-O stretching vibrations of CH_{3}OH and near the hydrogen out-of-plane bending vibration of C_{6}H_{6}. The initial identification of the new infrared bands observed was established by performing a conentration study (1:200 to 1:2000 S:M ratios), by comparing the co-deposition spectra with the spectra of the individual monomers, by matrix annealing experiments, and by performing experiments using isotopically labeled methanol (CD_{3}OD) and benzene (C_{6}D_{6}). Quantum chemical calculations were also performed for the CH_{3}OH-C_{6}H_{6} complex using density functional theory and ab initio methods. Two stable minima were found for the complex: one in which the CH_{3}OH is above the C_{6}H_{6} ring with the hydroxyl hydrogen interacting with the π cloud of the ring (H-π complex) and the other in which the CH_{3}OH is in the plane of the C_{6}H_{6} ring with the hydroxyl oxygen interacting with one of the C-H bonds of the ring (CH-O complex). Comparing the calculated shifts of the vibrational frequencies for both complexes to the observed experimental frequency shifts, it is found that the H-π complex is in best agreement with the experimental shifts in both magnitude and direction. Therefore, it is concluded that the geometry of the CH_{3}OH-C_{6}H_{6} complex observed in the matrix isolation experiments is the H-π complex.

  13. Assignment of IR bands of isolated and protein-bound Peridinin in its fundamental and triplet state by static FTIR, time-resolved step-scan FTIR and DFT calculations

    NASA Astrophysics Data System (ADS)

    Mezzetti, Alberto; Kish, Elizabeth; Robert, Bruno; Spezia, Riccardo

    2015-06-01

    The vibrational properties of Peridinin in its fundamental state and in the excited triplet state have been investigated by DFT calculations and static and time-resolved FTIR spectroscopy. The infrared spectrum of Peridinin in its fundamental state has been explored in the whole 2000-600 cm-1 range, and interpreted in term of molecular vibrations. In particular, new infrared bands have been identified and assigned to specific molecular vibrations. 3Peridinin molecular vibrations have also been investigated by DFT calculations. In addition, putative IR bands belonging to Peridinin and 3Peridinin have been identified in the step-scan FTIR difference spectrum of the Peridinin-Chlorophyll a-Protein from Amphidinium carterae, where light induce formation of a triplet state localized on one or more Peridinins. The exact nature of the triplet state formed in Peridinin-Chlorophyll a-Protein from dinoflagellates, in particular the possible involvement in this triplet state of 3Chlorophyll a, has been largely debated in the last few years (see Carbonera et al., 2014 [3]); time-resolved differential FTIR experiments have played a key role in this debate. Identification of IR marker bands for the main molecule (Peridinin) implicated in this photophysical process is therefore particularly important and makes this study a significant step towards the full understanding of Peridinin-Chlorophyll-a-Proteins photophysics.

  14. On the FCNS ⇆ FC(NS) reaction: A matrix isolation and theoretical study

    NASA Astrophysics Data System (ADS)

    Tajti, Attila; Mück, Leonie Anna; Farkas, Ádám László; Krebsz, Melinda; Pasinszki, Tibor; Tarczay, György; Szalay, Péter G.

    2015-04-01

    The FCNS ⇆ FC(NS) photoisomerization process is a simple model system for molecular switches. Here, we examined the switching processes by experimental and theoretical methods. Prior matrix-isolation IR spectroscopic studies were complemented by matrix-isolation UV spectroscopic measurements to assist the interpretation of the mechanism of the ring closure and opening processes and to verify the accuracy of the computations on the vertical excitation energies. Vertical excitation energies were computed by the EOMEE-CCSD, MCSCF, and MR-CISD methods. Conical intersections were also searched for and three conical intersections along the reaction path FCNS → FC(NS) were located, one conical intersection between the 2A‧ and 1A″ state, one between the 1A″ and 1A‧ state and one where all three states intersect. The ring opening and closing processes were simulated by non-adiabatic dynamics propagation with the trajectory surface hopping method. The combined computational and experimental results suggest that upon 365 nm irradiation the ring closure FCNS → FC(NS) occurs under participation of all three conical intersections, while 254 nm irradiation causes ring opening FC(NS) → FCNS. Both processes, especially the ring opening, are accompanied by fragmentation into FCN+S.

  15. Conformations of 1,1-diethoxyethane: A matrix isolation infrared and ab initio study

    NASA Astrophysics Data System (ADS)

    Venkatesan, V.; Viswanathan, K. S.

    2011-03-01

    Conformations of 1,1-diethoxyethane (DEE) were studied using matrix isolation infrared spectroscopy. Infrared features of the lowest energy, G∓G±(tt) conformer and the first higher energy, TG-(tt) conformer of matrix-isolated DEE were observed for the first time. The experiments were supported by ab initio computations performed at the HF and B3LYP levels, using a 6-31++G** basis set. The computed vibrational wavenumbers at the B3LYP/6-31++G** level for the G∓G±(tt) and TG-(tt) conformers, were found to agree well with the experimentally observed features, leading to a definitive assignment of the infrared features of these conformers of DEE. At the B3LYP/6-31++G** level, the energy of TG-(tt) conformer was found to be 0.42 kcal/mol above the ground state G∓G±(tt) conformer. AIM calculations were also performed to understand the role of intramolecular Csbnd H⋯O interaction in the conformational preferences in DEE.

  16. Infrared Spectrum and UV-Induced Photochemistry of Matrix-Isolated 5-Hydroxyquinoline.

    PubMed

    Kuş, Nihal; Sagdinc, Seda; Fausto, Rui

    2015-06-18

    The structure, infrared spectrum, and photochemistry of 5-hydroxyquinoline (5HQ) were studied by matrix isolation infrared spectroscopy, complemented by theoretical calculations performed at the DFT(B3LYP)/6-311++G(d,p) level of approximation. According to the calculations, the trans conformer of 5HQ (with the OH group pointing to the opposite direction of the pyridine ring of the molecule) is more stable than the cis form (by ∼8.8 kJ mol(-1)). The main factors determining the relative stability of the two conformers were rationalized through natural bond orbital (NBO) and charge density analyses. The compound was trapped in solid nitrogen at 10 K, and its infrared spectra registered and interpreted, showing the sole presence in the matrix of the more stable trans conformer. Broadband in situ UV irradiations (λ ≥ 288 nm and λ ≥ 235 nm) allowed for the observation of different chemical transformations, which started by excitation to the S1 state of 5HQ, followed by homolytic cleavage of the O-H bond, and subsequent reattachment of the H atom to the 5HQ radical to form quinolin-5(6H)-one and quinolin-5(8H)-one. The first of these two quinolinones was found to convert to open-ring isomeric ketenes, especially when irradiation was performed at higher energy, whereas the second is rather stable under the used experimental conditions. As a whole, the observed photochemistry of matrix-isolated 5HQ closely matches those previously reported for phenol and thiophenol. A detailed mechanistic interpretation for the observed photochemical processes is here proposed, which received support from time-dependent DFT calculations. PMID:26024730

  17. Conformational cooling dynamics in matrix-isolated 1,3-butanediol.

    PubMed

    Rosado, Mário T S; Jesus, António J Lopes; Reva, Igor D; Fausto, Rui; Redinha, José S

    2009-07-01

    The complete conformational space of monomeric 1,3-butanediol has been characterized theoretically, and 73 unique stable conformers were found at the MP2/6-311++G(d,p) level. These were classified into nine families whose members share the same heavy atom backbone configurations and differ in the hydrogen atom orientations. The first and third most populated backbone families are governed by the formation of an intramolecular hydrogen bond; however, the second precludes this type of interaction and was frequently overlooked in previous studies. Its stability is determined by the relatively high entropy of its main conformers. The hydrogen bonding of four of the most important conformers was characterized by means of atoms in molecules (AIM, also known as QTAIM) and natural bond orbital (NBO) analyses. Using appropriate isodesmic reactions, hydrogen bonding energy stabilizations of 12-14 kJ mol(-1) have been found. Experimentally, monomeric molecules of 1,3-butanediol were isolated in low-temperature inert matrixes, and their infrared spectra were analyzed from the viewpoint of the conformational distribution. All the relevant transition states for the conformational interconversion reaction paths were characterized at the same level of theory to interpret the conformational cooling dynamics observed in the low-temperature matrixes. The energy barriers for rotation of the OH groups were calculated to be very low (<3 kJ mol(-1)). These barriers were overcome in the experiments at 10 K (Ar matrix), in the process of matrix deposition, and population within each family was reduced to the most stable conformers. Further increase in the substrate temperature (up to 40 K, Xe matrix) resulted in conformational cooling where the medium-height barriers (approximately 13 kJ mol(-1)) could be surmounted and all conformational population converted to the ground conformational state. Remarkably, this state turned to consist of two forms of the most stable hydrogen bonded family

  18. Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Nitrogen Heterocycles (PANHs)

    NASA Technical Reports Server (NTRS)

    Mattioda, A. L.; Hudgins, D. M.; Bauschlicher, C. W.; Allamandola, L. J.; Biemesderfer, C. D.; Rosi, M.

    2002-01-01

    The mid-infrared spectra of the nitrogen-containing heterocyclic polycyclic aromatic compounds 1-azabenz[a]-anthracene; 2-azabenz[a]anthracene; 1-azachrysene; 2-azachrysene; 4-azachrysene; 2-azapyrene, and 7,8 benzoquinoline in their neutral and cation forms were investigated. The spectra of these species isolated in an argon matrix have been measured. Band frequencies and intensities were tabulated and these data compared with spectra computed using density functional theory at the B3LYP level. The overall agreement between experiment and theory is quite good, in keeping with earlier results on homonuclear polycyclic aromatic hydrocarbons. The differences between the spectral properties of nitrogen bearing aromatics and non-substituted, neutral polycyclic aromatic hydrocarbons will be discussed.

  19. 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.

  20. Genetic analysis of phosphoprotein and matrix protein of rabies viruses isolated in Brazil.

    PubMed

    Kobayashi, Yuki; Okuda, Hiromi; Nakamura, Kana; Sato, Go; Itou, Takuya; Carvalho, Adolorata A B; Silva, Marlon V; Mota, Carla S; Ito, Fumio H; Sakai, Takeo

    2007-11-01

    To investigate the genetic characteristics of phosphoprotein (P) and matrix protein (M) genes of variable rabies virus (RV) prevalent in Brazil, the authors genetically characterized the P and M genes from 30 Brazilian RV field isolates. Phylogenetic analysis based on the P and M genes revealed the presence of six RV variants that consisted primarily of three insectivorous bats, the vampire bat, dog and fox in Brazil. Specific amino acid substitutions corresponding to these phylogenetic lineages were observed, with Asp(42) and Glu(62) in the P protein found to be characteristic of Brazilian chiroptera- and carnivora-related RVs, respectively. Amino acid sequence motifs predicted to associate with a viral function in the P and M proteins were conserved among Brazilian RV variants. PMID:18057829

  1. Investigation of Praseodymium Fluorides: A Combined Matrix-Isolation and Quantum-Chemical Study.

    PubMed

    Vent-Schmidt, Thomas; Riedel, Sebastian

    2015-12-01

    The chemistry of the lanthanides is mostly dominated by compounds in the oxidation state +III. Only few compounds of Ce, Pr, and Tb are known with the metal in the +IV oxidation state. Removal of the last f-electron on praseodymium +IV would lead to a closed-shell system with formal oxidation state V. In this work we investigated the stability of the PrF5 molecule by theory and matrix-isolation techniques through the reaction of laser-ablated praseodymium atoms with fluorine in excess of neon, argon, krypton, or neat fluorine. Besides the known PrF3 molecule, unreported IR bands for PrF4 could be observed, and there is evidence for the formation of PrF and PrF2 but not for the formation of PrF5. PMID:26544761

  2. Examinations of the matrix isolation fourier transform infrared spectra of organic compounds: Part XII

    SciTech Connect

    Coleman, W. M., III; Gordon, B. M.; Lawrence, B. M.

    1989-02-01

    Matrix isolation Fourier transform infrared spectra (MI/FT-IR), massspectra (MS), carbon-13 Nuclear Magnetic Resonance (/sup 13/C-NMR) spectra,condensed-phase infrared spectra, and vapor-phase infrared (IR)spectra are presented for a series of terpene compounds. Subtle differencesin positional and configurational isomers commonly found withterpenes could be easily detected by the MI/FT-IR spectra. The resultsare comparable in some aspects to those obtainable from /sup 13/C-NMR andthin-film IR; however, most importantly, they are acquired at the lownanogram level for MI/FT-IR, as compared to the milligram level forthe other techniques. These results represent an advance in the technologyavailable for the analysis of complex mixtures such as essential oilscontaining terpene-like molecules.

  3. Reaction of trimethylsilylacetylenes with antimony pentafluoride under matrix isolation conditions: experimental and computational study.

    PubMed

    Cicak, Helena; Vancik, Hrvoj; Mihalić, Zlatko

    2010-10-15

    Reaction of trimethylsilylacetylenes Me(3)SiC≡CR with SbF(5) in the solid state was investigated using matrix isolation infrared spectroscopy and quantum-mechanical calculations. Two reaction pathways were detected. Replacement of the trimethylsilyl group with SbF(4) produces neutral antimony acetylides F(4)SbC≡CR. Acetylenic bond protonation produces silyl cation 6-R, fully bridged for R = H and SiMe(3). High total charges on the bridging SiMe(3) group and low Me(3)Si-C bond orders to acetylenic moiety, both calculated at the MP4(SDQ)/6-311G(d,p) level of theory, indicate high silyl cation character of these species. PMID:20857942

  4. The Infrared Spectrum of Matrix Isolated Aminoacetonitrile: A Precursor to the Amino Acid Glycine

    NASA Technical Reports Server (NTRS)

    Bernstein, Max P.; Bauschlicher, Charles W., Jr.; Sandford, Scott A.

    2003-01-01

    We present infrared (IR) spectral data from matrix isolation experiments and density functional theory calculations on the pre-biologically interesting molecule aminoacetonitrile, a precursor to glycine. We find that this nitrile has an unusually weak nitrile (C=N) stretch in the infrared, in contrast to expectations based on measurements and models of other nitriles under astrophysical conditions. The absence of an observable nitrile absorption feature in the infrared will make the IR search for this molecule considerably more difficult, and will raise estimates of upper limits on nitriles in interstellar and outer Solar System ices. This is also of relevance to assessing the formation routes of the amino acid glycine, since aminoacetonitrile is the putative precursor to glycine via the Strecker synthesis, the mechanism postulated to have produced the amino acids in meteorites.

  5. Low-energy excited states of divanadium: a matrix isolation and MRCI study.

    PubMed

    Hübner, Olaf; Himmel, Hans-Jörg

    2016-06-01

    The ground and excited electronic states of the vanadium dimer (V2) have been studied using Ne matrix isolation experiments and quantum chemical calculations (multireference configuration interaction based on complete active space self-consistent orbitals). In the near infrared absorption spectrum, two vibrational progressions of a new electronic term with a large number of members have been observed with the origin at 1.08 eV and a fundamental vibrational quantum of 475 cm(-1). With the aid of calculations, it has been assigned to a (3)Πu electronic term. The calculations yield potential energy curves for a large number of singlet, triplet, and quintet electronic terms. PMID:27182729

  6. Matrix-isolation study and ab initio calculations of the structure and spectra of hydroxyacetone.

    PubMed

    Sharma, Archna; Reva, Igor; Fausto, Rui

    2008-07-01

    The structure of hydroxyacetone (HA) isolated in an argon matrix (at 12 K) and in a neat solid phase (at 12-175 K) was characterized by using infrared (IR) spectroscopy. The interpretation of the experimental results was supported by high-level quantum chemical calculations, undertaken by using both ab initio (MP2) and density functional theory methods. A potential-energy surface scan, carried out at the MP2/6-311++G(d,p) level of theory, predicted four nonequivalent minima, Cc, Tt, Tg, and Ct, all of them doubly degenerate by symmetry. The energy barriers for conversion between most of the symmetrically related structures and also between some of the nonequivalent minima (e.g., Tg --> Tt and Ct --> Tt) are very small and stay below the zero-point vibrational level associated with the isomerization coordinate in the higher-energy form in each pair. Therefore, only Cc and Tt conformers have physical significance, with populations of 99 and 1%, respectively, in gas phase at room temperature. For the matrix-isolated compound, only the most stable Cc conformer was observed. On the other hand, the polarizable continuum model calculations indicated that in water solution, the population of Tt and Ct conformers might be high enough (ca. 6 and 11%, respectively) to enable their experimental detection, thus supporting the conclusions of a previous IR spectroscopy study [ Spectrochim. Acta A 2005, 61, 477] in which the presence of more than one HA conformer in aqueous solution was postulated. The signatures of these minor conformers, however, do not appear in the spectra of the neat HA crystal, and the crystal structure was rationalized in terms of centrosymmetric hydrogen-bonded dimers consisting of two Cc-like units. Finally, we calculated (1)H, (13)C, and (17)O NMR chemical shifts at different levels of theory and found them to agree with available experimental data. PMID:18537231

  7. Matrix isolation infrared spectroscopic study of the vapor species over heated ReO{sub 3}

    SciTech Connect

    Almond, M.J.; Orrin, R.H.; Ogden, J.S.

    1996-02-01

    The vapor phase species over ReO{sub 3} heated in vacuo to approx 400C have been trapped in argon or nitrogen matrices at approx 12 K. The only species within such matrices detected by infrared spectroscopy is Re{sub 2}O{sub 7}. The bands of matrix-isolated Re{sub 2}O{sub 7} have been assigned by comparison with the spectrum of the gaseous compound. Most of the isolated Re{sub 2}O{sub 7} is shown to be in the monomeric form; thus, an infrared absorption at 916.5 cm{sup {minus}1} (N{sub 2} matrix), which had previously been assigned to an aggregate of Re{sub 2}O{sub 7} may, on the basis of annealing experiments, be attributed to the monomer. The solid remaining in the sample tube following heating of the ReO{sub 3} sample consists of ReO{sub 2} in both the monoclinic and orthorhombic crystal forms alongside some unreacted cubic ReO{sub 3} and a small amount of orthorhombic Re{sub 2}O{sub 7}. Thus, it is found that thermal decomposition of ReO{sub 3} in vacuo at 400 C follows the expected disproportionation route. The authors find no spectroscopic evidence for the existence of other species, such as ReO{sub 3} or HReO{sub 4}, in the vapor above heated ReO{sub 3}. This finding is in contrast to the results of earlier mass spectrometric studies that suggested that molecular ReO{sub 3} was present in the vapor together with Re{sub 2}O{sub 7}.

  8. Isolation and identification of oxidation products of syringol from brines and heated meat matrix.

    PubMed

    Bölicke, Sarah-Maria; Ternes, Waldemar

    2016-08-01

    In this study we developed new extraction and detection methods (using HPLC-UV and LC-MS), making it possible to analyze the smoke phenol syringol and its oxidation products nitrososyringol, nitrosyringol, and the syringol dimer 3,3',5,5'-tetramethoxy-1,1'-biphenyl-4,4'-diol, which were identified in heated meat for the first time. Preliminary brine experiments performed with different concentrations of ascorbic acid showed that high amounts of this antioxidant also resulted in almost complete degradation of syringol and to formation of the oxidation products when the brines were heated at low pH values. Heat treatment (80°C) and subsequent simulated digestion applied to meat samples containing syringol, ascorbic acid and different concentrations of sodium nitrite produced 3,3',5,5'-tetramethoxy-1,1'-biphenyl-4,4'-diol even at a low nitrite level in the meat matrix, while nitroso- and nitrosyringol were isolated only after the digestion experiments. Increasing amounts of oxygen in the meat matrix decreased the syringol concentration and enhanced the formation of the reaction products in comparison to the samples without added oxygen. PMID:27085115

  9. Design and performance of a throughput-matched, zero-geometric-loss, modified three objective multipass matrix system for FTIR spectrometry.

    PubMed

    Glowacki, David R; Goddard, Andrew; Seakins, Paul W

    2007-11-10

    The design of and initial results obtained from a multipass matrix system (MMS) for mid-infrared spectroscopy that operates in the Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC) recently constructed in the School of Chemistry at the University of Leeds, is described. HIRAC is an evacuable, temperature variable, photochemical atmospheric reaction chamber. The MMS design is a modified Chernin cell, utilizing three objective mirrors and two field mirrors. In addition to providing the paraxial equations required for design of a throughput matched multipass cell and throughput matched transfer optics, advanced ray tracing simulations have been performed for the Chernin design described herein. The simulations indicate that, for this MMS, which features small off-axis angles and preserves perfectly the focal properties of the original White design, the paraxial equations are nearly exact, throughput losses due to astigmatism are insignificant, and the system has zero theoretical geometric loss. Measurements of the signal incident on the detector at different matrix arrangements confirm the ray trace results, suggesting that geometric loss in this system is insignificant. The MMS described herein provides adequate stability to permit measurements while the chamber mixing fans are on, gives very good detection limits for some representative species, and is easy to align. PMID:17994138

  10. Evaluation of fourier transform infrared (FT-IR) spectroscopy and chemometrics as a rapid approach for subtyping E. coli O157:H7 isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The importance of tracking outbreaks of foodborne illness and the emergence of new virulent subtypes of foodborne pathogens have created the need for rapid and reliable subtyping methods for Escherichia coli O157:H7. Fourier transform infrared (FT-IR) spectroscopy coupled with multivariate statistic...

  11. Isolation and quantification of botulinum neurotoxin from complex matrices using the BoTest matrix assays.

    PubMed

    Dunning, F Mark; Piazza, Timothy M; Zeytin, Füsûn N; Tucker, Ward C

    2014-01-01

    Accurate detection and quantification of botulinum neurotoxin (BoNT) in complex matrices is required for pharmaceutical, environmental, and food sample testing. Rapid BoNT testing of foodstuffs is needed during outbreak forensics, patient diagnosis, and food safety testing while accurate potency testing is required for BoNT-based drug product manufacturing and patient safety. The widely used mouse bioassay for BoNT testing is highly sensitive but lacks the precision and throughput needed for rapid and routine BoNT testing. Furthermore, the bioassay's use of animals has resulted in calls by drug product regulatory authorities and animal-rights proponents in the US and abroad to replace the mouse bioassay for BoNT testing. Several in vitro replacement assays have been developed that work well with purified BoNT in simple buffers, but most have not been shown to be applicable to testing in highly complex matrices. Here, a protocol for the detection of BoNT in complex matrices using the BoTest Matrix assays is presented. The assay consists of three parts: The first part involves preparation of the samples for testing, the second part is an immunoprecipitation step using anti-BoNT antibody-coated paramagnetic beads to purify BoNT from the matrix, and the third part quantifies the isolated BoNT's proteolytic activity using a fluorogenic reporter. The protocol is written for high throughput testing in 96-well plates using both liquid and solid matrices and requires about 2 hr of manual preparation with total assay times of 4-26 hr depending on the sample type, toxin load, and desired sensitivity. Data are presented for BoNT/A testing with phosphate-buffered saline, a drug product, culture supernatant, 2% milk, and fresh tomatoes and includes discussion of critical parameters for assay success. PMID:24638074

  12. EVALUATION OF GAS CHROMATOGRAPHY/MATRIX ISOLATION INFRARED SPECTROMETRY FOR THE DETERMINATION OF SEMIVOLATILE ORGANIC COMPOUNDS IN AIR SAMPLE EXTRACTS

    EPA Science Inventory

    The capabilities of gas chromatography/matrix isolation-infrared (GC/MI-IR) spectrometry for determination of semivolatile organic compounds (SVOCs) in air sample extracts were evaluated. ystematic experiment, using xylene isomers as test compounds, were conducted to determine th...

  13. Analytic Confusion Matrix Bounds for Fault Detection and Isolation Using a Sum-of-Squared- Residuals Approach

    NASA Technical Reports Server (NTRS)

    Simon, Dan; Simon, Donald L.

    2009-01-01

    Given a system which can fail in 1 or n different ways, a fault detection and isolation (FDI) algorithm uses sensor data in order to determine which fault is the most likely to have occurred. The effectiveness of an FDI algorithm can be quantified by a confusion matrix, which i ndicates the probability that each fault is isolated given that each fault has occurred. Confusion matrices are often generated with simulation data, particularly for complex systems. In this paper we perform FDI using sums of squares of sensor residuals (SSRs). We assume that the sensor residuals are Gaussian, which gives the SSRs a chi-squared distribution. We then generate analytic lower and upper bounds on the confusion matrix elements. This allows for the generation of optimal sensor sets without numerical simulations. The confusion matrix bound s are verified with simulated aircraft engine data.

  14. Matrix isolation infrared spectra of hydrogen halide and halogen complexes with nitrosyl halides

    NASA Technical Reports Server (NTRS)

    Allamandola, Louis J.; Lucas, Donald; Pimentel, George C.

    1982-01-01

    Matrix isolation infrared spectra of nitrosyl halide (XNO) complexes with HX and X2 (X = Cl, Br) are presented. The relative frequency shifts of the HX mode are modest (ClNO H-Cl, delta-nu/nu = -0.045; BrNO H-Br, delta-nu/nu = -0.026), indicating weak hydrogen bonds 1-3 kcal/mol. These shifts are accompanied by significant shifts to higher frequencies in the XN-O stretching mode (CIN-O HCl, delta-nu/nu = +0.016; BrN-O HBr, delta-nu/nu = +0.011). Similar shifts were observed for the XN-O X2 complexes (ClN-O Cl2, delta-nu/nu = +0.009; BrN-O-Br2, delta-nu/nu = +0.013). In all four complexes, the X-NO stretching mode relative shift is opposite in sign and about 1.6 times that of the NO stretching mode. These four complexes are considered to be similar in structure and charge distribution. The XN-O frequency shift suggests that complex formation is accompanied by charge withdrawal from the NO bond ranging from about .04 to .07 electron charges. The HX and X2 molecules act as electron acceptors, drawing electrons out of the antibonding orbital of NO and strengthening the XN-O bond. The implications of the pattern of vibrational shifts concerning the structure of the complexes are discussed.

  15. Isolation and identification of oxidation products of guaiacol from brines and heated meat matrix.

    PubMed

    Bölicke, Sarah-Maria; Ternes, Waldemar

    2016-07-01

    In this study we investigated the formation of the oxidation products of guaiacol in brines and heated meat matrix: 6-nitrosoguaiacol, 4-nitroguaiacol and 6-nitroguaiacol. For this purpose we applied a newly developed HPLC-UV and LC-MS method. For the first time, 6-nitrosoguaiacol was determined in brine and meat (containing guaiacol and sodium nitrite), which had been heated to 80°C and subsequently subjected to simulated digestion. Application of 500mg/L ascorbic acid to the brines reduced guaiacol degradation at pH3 and simultaneously inhibited the formation of 6-nitrosoguaiacol compared to brines containing only 100mg/L of ASC. The oxidation products were isolated with a new extraction method from meat samples containing 400mg/kg sodium nitrite at pH3.6 following simulated digestion. When oxygen was added, 6-nitrosoguaiacol was determined even at legally allowed levels (150mg/kg) of the curing agent. Finally, we developed a new LC-MS method for the separation and qualitative determination of the four main smoke methoxyphenols. PMID:26937586

  16. The UV/Vis absorption spectrum of matrix-isolated dichlorine peroxide, ClOOCl.

    PubMed

    von Hobe, Marc; Stroh, Fred; Beckers, Helmut; Benter, Thorsten; Willner, Helge

    2009-03-14

    UV/Vis absorption spectra of ClOOCl isolated in neon matrices were measured in the wavelength range 220-400 nm. The purity of the trapped samples was checked by infrared and UV/Vis matrix spectroscopy as well as low-temperature Raman spectroscopy. At wavelengths below 290 nm, the results agree with the UV spectrum recently published by Pope et al. [J. Phys. Chem. A, 2007, 111, 4322-4332]. However, the observed absorption in the long wavelength tail of the spectrum-relevant for polar stratospheric ozone loss-is substantially higher than reported by Pope et al. Our results suggest the existence of a ClOOCl electronic state manifold leading to an absorption band similar to those of the near UV spectrum of Cl(2). The differences to previous studies can be accounted for quantitatively by contributions to the reported absorption spectra caused by impurities. The observed band in the long wavelength tail is supported by several high-level ab initio calculations. However, questions arise concerning absolute values of the ClOOCl cross sections, an issue that needs to be revisited in future studies. With calculated photolysis rates based on our spectrum scaled to previous cross sections at the peak absorption, the known polar catalytic ozone-destruction cycles to a large extent account for the observed ozone depletion in the spring polar stratosphere. PMID:19240934

  17. Matrix isolation infrared and ab initio study of the hydrogen bonding between formic acid and water

    NASA Astrophysics Data System (ADS)

    George, Lisa; Sander, Wolfram

    2004-11-01

    The infrared spectra of the formic acid-water complexes isolated in argon matrices are reported. Both supersonic jet expansion and a conventional effusive source followed by trapping in solid argon at 10 K are used to obtain the matrices. The experimental IR spectra are compared to the data obtained from high level ab initio (MP2) and DFT (B3LYP) calculations with 6-311++G(d,p) and aug-cc-pVTZ basis sets. The complex formation results in red shifts in the CO and OH stretching vibrations and a blue shift in the CO stretching vibration of formic acid. The OH stretching modes of water also exhibit pronounced red shifts. Both the MP2 and B3LYP calculations located three minima corresponding to cyclic HCOOH⋯H 2O complexes with two hydrogen bond interactions. The binding energies are -10.3, -5.1, and -3.5 kcal mol -1, respectively, for the three complexes at the MP2/ aug-cc-pVTZ level, corrected for the basis set superposition error (BSSE) using the Boys-Bernardi counterpoise scheme. Comparison of the calculated frequencies of the three complexes with the matrix IR spectrum reveals that the lowest energy complex is formed. In addition, a complex of formic acid with two water molecules is observed.

  18. Time-resolved fluorescence spectroscopy of matrix-isolated silver atoms after pulsed excitation of inner-shell transitions

    NASA Astrophysics Data System (ADS)

    Hebert, T.; Wiggenhauser, H.; Schriever, U.; Kolb, D. M.

    1990-02-01

    The energy dissipation in matrix-isolated silver atoms after pulsed vacuum ultraviolet (VUV) excitation of 4d-5p transitions has been studied by time-resolved fluorescence spectroscopy. The decay behavior of the various fluorescence bands has been analyzed and a model for the relaxation process proposed within the framework of a two-dimensional configuration-coordinate diagram. If minute quantities of Ag2 are present in the matrix, the analysis requires consideration of energy transfer between silver atoms and dimers.

  19. Infrared spectroscopy of polycyclic aromatic hydrocarbon cations. 1: Matrix-isolated naphthalene and perdeuterated naphthalene

    NASA Technical Reports Server (NTRS)

    Hudgins, D. M.; Sandford, S. A.; Allamandola, Louis J.

    1994-01-01

    Ionized polycyclic aromatic hydrocarbons (PAHs) are thought to constitute an important component of the interstellar medium. Despite this fact, the infrared spectroscopic properties of ionized PAHs are almost unknown. The results we present here derive from our ongoing spectroscopic study of matrix isolated PAH ions and include the spectra of the naphthalene cation, C10H8(+), and its fully deuterated analog, C10D8(+), between 4000 and 200/cm. Ions are generated by in situ Lyman-alpha photoionization of the neutral precursor. Bands of the C10H8(+) ion are observed at 1525.7, 1518.8, 1400.9, 1218.0, 1216.9, 1214.9, 1023.2, and 758.7/cm. Positions and relative intensities of these bands agree well with those in the available literature. The 758.7/cm band has not previously been reported. C10D8(+) ion bands appear at 1466.2, 1463.8, 1379.4, 1373.8, 1077.3, 1075.4, and 1063.1/cm. Compared to the analogous modes in the neutral molecule, the intensities of the cation's CC modes are enhanced by an order of magnitude, while CH modes are depressed by this same factor. Integrated absorption intensities are calculated for the strongest bands of C10H8 and for the observed bands of C10H8(+). Absolute intensities derived for the naphthalene cation differ from earlier experimental results by a factor of approximately 50, and from theoretical predictions by a factor of approximately 300. Reasons for these discrepancies and from the astronomical implications of PAH cation spectra are discussed.

  20. Luminescence spectroscopy of matrix-isolated z 6P state atomic manganese.

    PubMed

    Collier, Martin A; McCaffrey, John G

    2005-05-01

    The relaxation of electronically excited atomic manganese isolated in solid rare gas matrices is observed from recorded emission spectra, to be strongly site specific. z 6P state excitation of Mn atoms isolated in the red absorption site in Ar and Kr produces narrow a 4D and a 6D state emissions while blue-site excitation produces z 6P state fluorescence and broadened a 4D and a 6D emissions. MnXe exhibits only a single thermally stable site whose emission at 620 nm is similar to the broad a 6D bands produced with blue-site excitation in Ar and Kr. Thus in Ar(Kr), excitation of the red site at 393 (400) nm produces narrow line emissions at 427.5 (427.8) and 590 (585.7) nm. From their spectral positions, linewidths, and long decay times, these emission bands are assigned to the a 4D72 and a 6D92 states, respectively. Excitation of the blue site at 380 (385.5) nm produces broad emission at 413 (416) nm which, because of its nanosecond radiative lifetime, is assigned to resonance z 6P --> a 6S fluorescence. Emission bands at 438 (440) and 625 (626.8) nm, also produced with blue-site excitation, are broader than their red-site equivalents at 427.5 and 590 nm (427.8 and 585.7 nm in Kr) but from their millisecond and microsecond decay times are assigned to the a 4D and a 6D states. The line features observed in high resolution scans of the red-site emission at 427.5 and 427.8 nm in MnAr and MnKr, respectively, have been analyzed with the W(p) optical line shape function and identified as resolved phonon structure originating from very weak (S=0.4) electron-phonon coupling. The presence of considerable hot-phonon emission (even in 12 K spectra) and the existence of crystal field splittings of 35 and 45 cm(-1) on the excited a 4D72 level in Ar and Kr matrices have been identified in W(p) line shape fits. The measured matrix lifetimes for the narrow red-site a 6D state emissions (0.29 and 0.65 ms) in Ar and Kr are much shorter than the calculated (3 s) gas phase value. With

  1. Differentiation of Aeromonas isolated from drinking water distribution systems using matrix-assisted laser desorption/ionization-mass spectrometry.

    PubMed

    Donohue, Maura J; Best, Jennifer M; Smallwood, Anthony W; Kostich, Mitchell; Rodgers, Mark; Shoemaker, Jody A

    2007-03-01

    The genus Aeromonas is one of several medically significant genera that have gained prominence due to their evolving taxonomy and controversial role in human diseases. In this study, matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) was used to analyze the whole cells of both reference strains and unknown Aeromonas isolates obtained from water distribution systems. A library of over 45 unique m/z signatures was created from 40 strains that are representative of the 17 recognized species of Aeromonas, as well as 3 reference strains from genus Vibrio and 2 reference strains from Plesiomonas shigelloides. The library was used to help speciate 52 isolates of Aeromonas. The environmental isolates were broken up into 2 blind studies. Group 1 contained isolates that had a recognizable phenotypic profile and group 2 contained isolates that had an atypical phenotypic profile. MALDI-MS analysis of the water isolates in group 1 matched the phenotypic identification in all cases. In group 2, the MALDI-MS-based determination confirmed the identity of 18 of the 27 isolates. These results demonstrate that MALDI-MS analysis can rapidly and accurately classify species of the genus Aeromonas, making it a powerful tool especially suited for environmental monitoring and detection of microbial hazards in drinking water. PMID:17269751

  2. Conformations of dimethyl carbonate and its complexes with water: A matrix isolation infrared and ab initio study

    NASA Astrophysics Data System (ADS)

    Kar, Bishnu Prasad; Ramanathan, N.; Sundararajan, K.; Viswanathan, K. S.

    2012-09-01

    Conformations of dimethyl carbonate (DMC) were studied using matrix isolation infrared spectroscopy. Infrared spectra of DMC trapped in inert gas matrixes, using an effusive source at 298 and 423 K, showed evidence of both the ground state (cis-cis), and higher energy (cis-trans) conformers. Experiments were also performed using a supersonic jet source to deposit the matrix, to look for conformational cooling in the expansion process. The structures and vibrational frequencies of these conformers were computed at the B3LYP/6-31++G** level of theory. Natural bond orbital analyses were performed to understand the role of the delocalization interactions in conformational preferences. Complexes of DMC with H2O were also studied. A 1:1 DMC-H2O complex was identified in the matrix isolation experiments, where the carbonyl oxygen of DMC served as the proton acceptor for the hydrogen bonded complex. This observation was corroborated by computations performed on the complex at the B3LYP/6-31++G** level. Our computations also indicated another minimum, corresponding to an alkoxy bonded DMC-H2O complex, which was less exothermic; however, this complex was not identified in our experiments. Atoms-in-molecules theory was also performed to understand the nature of the intermolecular interaction in the DMC-H2O complex.

  3. Evaluation of the Bruker Biotyper Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System for Identification of Blood Isolates of Acinetobacter Species

    PubMed Central

    Hsueh, Po-Ren; Kuo, Lu-Cheng; Chang, Tsung-Chain; Lee, Tai-Fen; Teng, Shih-Hua; Chuang, Yu-Chung; Teng, Lee-Jene

    2014-01-01

    Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) (Bruker Biotyper) was able to accurately identify 98.6% (142/144) of Acinetobacter baumannii isolates, 72.4% (63/87) of A. nosocomialis isolates, and 97.6% (41/42) of A. pittii isolates. All Acinetobacter junii, A. ursingii, A. johnsonii, and A. radioresistens isolates (n = 28) could also be identified correctly by Bruker Biotyper. PMID:24899038

  4. A spectroscopic study of intermediates in the condensation of refractory smokes: Matrix isolation experiments SiO

    NASA Technical Reports Server (NTRS)

    Khanna, R. K.; Stranz, D. D.; Donn, D.

    1980-01-01

    The infrared and Raman spectra of N2 matrix isolated silicon oxides are investigated. The vibrational frequencies of SiO, Si2O2, and Si3O3 were identified and assigned on the basis of normal coordinate analyses. Heating the solid to 50 K (evaporating the matrix) leaves a residue whose infrared spectrum is identical to that of a smoke condensed at ambient temperatures. Further heating of the sample to 500 K leads to significant changes in the band shapes. Investigations of the infrared spectra at several stages of the diffusion process result in the proposal of a mechanism for the transition from molecular properties to those of the residue (bulk) material, which is characterized as Si2O3.

  5. FTIR gas chromatographic analysis of perfumes

    NASA Astrophysics Data System (ADS)

    Diederich, H.; Stout, Phillip J.; Hill, Stephen L.; Krishnan, K.

    1992-03-01

    Perfumes, natural or synthetic, are complex mixtures consisting of numerous components. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) techniques have been extensively utilized for the analysis of perfumes and essential oils. A limited number of perfume samples have also been analyzed by FT-IR gas chromatographic (GC-FTIR) techniques. Most of the latter studies have been performed using the conventional light pipe (LP) based GC-FTIR systems. In recent years, cold-trapping (in a matrix or neat) GC-FTIR systems have become available. The cold-trapping systems are capable of sub-nanogram sensitivities. In this paper, comparison data between the LP and the neat cold-trapping GC- FTIR systems is presented. The neat cold-trapping interface is known as Tracer. The results of GC-FTIR analysis of some commercial perfumes is also presented. For comparison of LP and Tracer GC-FTIR systems, a reference (synthetic) mixture containing 16 major and numerous minor constituents was used. The components of the mixture are the compounds commonly encountered in commercial perfumes. The GC-FTIR spectra of the reference mixture was obtained under identical chromatographic conditions from an LP and a Tracer system. A comparison of the two sets of data thus generated do indeed show the enhanced sensitivity level of the Tracer system. The comparison also shows that some of the major components detected by the Tracer system were absent from the LP data. Closer examination reveals that these compounds undergo thermal decomposition on contact with the hot gold surface that is part of the LP system. GC-FTIR data were obtained for three commercial perfume samples. The major components of these samples could easily be identified by spectra search against a digitized spectral library created using the Tracer data from the reference mixture.

  6. An atomic beam of 6Li — 7Li for high resolution spectroscopy from matrix isolation sublimation

    NASA Astrophysics Data System (ADS)

    Oliveira, A. N.; Sacramento, R. L.; Silva, B. A.; Uhlmann, F. O.; Wolff, W.; Cesar, C. L.

    2016-07-01

    We propose the Matrix Isolation Sublimation (MlSu) technique for generating cold lithium atoms for the measurement of the 6Li - 7Li isotope shift in D1 and D2 transitions. The technique is capable of generating cold 6Li and 7Li beams at 4 K with forward velocity of 125 m/s. Using this beam we offer a distinguished source of lithium atoms for transitions measurements, adding a new possibility to make high resolution spectroscopy towards improving the experimental checks of the theory.

  7. GAS CHROMATOGRAPHY/MATRIX ISOLATION - INFRARED SPECTROMETRY FOR AIR SAMPLE ANALYSIS

    EPA Science Inventory

    This report describes the application of gas chromatography/matrix- solation infrared (GC/MI-IR) spectrometry to the analysIs of environmental air sample extracts. Samples that were analyzed include extracts from woodsmoke-impacted air, XAD-2 blanks, indoor air, and carpet sample...

  8. Matrix-isolation infrared investigation of the flash vacuum thermolysis of norbornadienone azine

    NASA Astrophysics Data System (ADS)

    Stroh, F.; Winnewisser, B. P.; Winnewisser, M.; Reisenauer, H. P.; Maier, G.; Goede, S. J.; Bickelhaupt, F.

    1989-08-01

    The flash vacuum thermolysis of norbornadienone azine over the temperature range 300 to 800°C was investigated by matrixisolation IR methods. The following thermolysis products could be identified: isocyanogen, cyanogen, benzene, benzonitrile and hydrogen cyanide. A tentative assignment of the infrared-active ν 2 stretching vibration of diisocyanogen, CNNC, in an argon matrix is made. The peak positions of four fundamentals (ν 1 to ν 4) of isocyanogen, CNCN, and of two stretching fundamentals (ν 1 and ν 2) of 13CNCN, CN 13CN, C 15NCN and CNC 15N in an argon matrix were measured. Combination bands yielded a value for ν 5 of CNCN. A molecular force field for CNCN was determined.

  9. On-line electrodialytic matrix isolation for chromatographic determination of organic acids in wine.

    PubMed

    Ohira, Shin-Ichi; Kuhara, Kenta; Shigetomi, Aki; Yamasaki, Takayuki; Kodama, Yuko; Dasgupta, Purnendu K; Toda, Kei

    2014-10-31

    Chromatographic determination of organic acids is widely performed, but the matrix often calls for lengthy and elaborate sample preparation prior to actual analysis. Matrix components, e.g., proteins, non-ionics, lipids etc. are typically removed by a combination of centrifugation/filtration and solid phase extraction (SPE) that may include the use of ion-exchange media. Here we report the quantitative electrodialytic transfer of organic acids from complex samples to ultrapure water in seconds using cellulose membranes modified with N,N-dimethylaminoethyl methacrylate, which essentially eliminates the negative ζ-potential of a regenerated cellulose membrane surface. The transfer characteristics of the ion transfer device (ITD) were evaluated with linear carboxylic acids. While the ion transfer efficiencies may be affected by the acid dissociation constants, in most cases it is possible to achieve quantitative transfer under optimized device residence time (solution flow rate) and the applied voltage. In addition, the transfer efficiency was unaffected by the wide natural variation of pH represented in real samples. The approach was applied to organic acids in various samples, including red wine, considered to represent an especially difficult matrix. While quantitative transfer of the organic acids (as judged by agreement with standard pretreatment procedures involving SPE) was achieved, transfer of other matrix components was <5%. The processed samples could then be chromatographically analyzed in a straightforward manner. We used ion exclusion chromatography with direct UV detection; in treated samples; there was a dramatic reduction of the large early peaks observed compared to only 0.45μm membrane filtered samples. PMID:25465003

  10. Infrared matrix-isolation spectroscopy using pulsed deposition of p-H2

    NASA Astrophysics Data System (ADS)

    Wu, Yu-Jong; Yang, Xueming; Lee, Yuan-Pern

    2004-01-01

    We employed pulsed deposition of p-H2 onto a cold target to form a matrix sample suitable for measurements of infrared absorption. Unlike the method of rapid vapor deposition at ˜2.5 K, developed by Fajardo et al., this method can be performed at a temperature as high as 5.5 K, achievable with a closed-cycle refrigerator; pumping on liquid helium in a cryostat is eliminated. Compared with the enclosed-cell method developed by Oka, Shida, Momose, and co-workers, this method is more versatile in sample preparation, especially for samples at a greater concentration or with high reactivity. Two experiments were tested: the pulse-deposited sample of CH4/p-H2 yields an infrared absorption spectrum nearly identical to that recorded with rapid vapor deposition, and a sample of vinyl chloride (C2H3Cl) in solid p-H2 irradiated with laser emission at 193 nm yields C2H5, in contrast to formation of HCl, C2H2, and a complex of HClṡC2H2 observed upon photolysis of C2H3Cl in an Ar matrix. These experiments are also compared with those with n-H2 or Ne as the matrix host.

  11. Matrix-Isolated Infrared Absorption Spectrum of CH2IOO Radical.

    PubMed

    Zhang, Xu; Sander, Stanley P; Cheng, Lan; Thimmakondu, Venkatesan S; Stanton, John F

    2016-01-21

    The peroxyiodomethyl radical, CH2IOO, was generated in cryogenic matrices using tandem supersonic nozzles. One hyperthermal nozzle decomposes diiodomethane (CH2I2) to generate intense beams of CH2I radicals, while the second nozzle continuously deposits O2/argon (Ar) on the matrix at 10 K. The CH2I and O2 in the Ar matrix react to produce the target peroxy radical (CH2IOO). The absorption spectra of the products are monitored with a Fourier transform infrared spectrometer. Eight of the 12 fundamental infrared bands for CH2IOO were observed in an argon matrix at 5 K. The experimental frequencies (cm(-1)) are ν3 = 1407.3, ν4 = 1230.4, ν5 = 1223.2, ν6 = 1085.3, ν7 = 919.9, ν8 = 839.9, ν9 = 567.5, and ν10 = 496.2. Additional confirmation for the vibrational assignment comes from a study of the CH2I(18)O(18)O isotopic species. The six observed frequencies (cm(-1)) for CH2I(18)O(18)O are ν3 = 1407.8, ν4 = 1228.0, ν6 = 1030.8, ν7 = 899.6, ν8 = 836.0, and ν10 = 494.6. Unlike CH2I(16)O(16)O, the ν5 and ν9 bands were not observed for CH2I(18)O(18)O. To guide the experimental analysis, ab initio calculations of the infrared spectrum based on second-order vibrational perturbation theory were performed using force fields computed with relativistic coupled-cluster methods. The experimental frequencies are shown to be in good agreement with the computed fundamental frequencies except for ν9 (for CH2IOO) and ν10 (for CH2I(18)O(18)O). Our findings were compared with the study by Lee and Lee conducted in a para-H2 matrix. The fundamental frequencies are in good agreement (within 6 cm(-1)) except for the two low-frequency modes, ν9 (for CH2IOO) and ν10 (for CH2I(18)O(18)O) likely due to different matrix shifts for para-H2 and Ar matrices. In addition, our calculations are in somewhat better agreement with the experiment values than the calculations by Lee and Lee. Our study also shows that reaction CH2I + O2 produces the peroxy radical CH2IOO in cold matrices (10

  12. Biomechanics of isolated tomato (Solanum lycopersicum L.) fruit cuticles: the role of the cutin matrix and polysaccharides.

    PubMed

    López-Casado, Gloria; Matas, Antonio J; Domínguez, Eva; Cuartero, Jesús; Heredia, Antonio

    2007-01-01

    The mechanical characteristics of the cuticular membrane (CM), a complex composite biopolymer basically composed of a cutin matrix, waxes, and hydrolysable polysaccharides, have been described previously. The biomechanical behaviour and quantitative contribution of cutin and polysaccharides have been investigated here using as experimental material mature green and red ripe tomato fruits. Treatment of isolated CM with anhydrous hydrogen fluoride in pyridine allowed the selective elimination of polysaccharides attached to or incrusted into the cutin matrix. Cutin samples showed a drastic decrease in elastic modulus and stiffness (up to 92%) compared with CM, which clearly indicates that polysaccharides incorporated into the cutin matrix are responsible for the elastic modulus, stiffness, and the linear elastic behaviour of the whole cuticle. Reciprocally, the viscoelastic behaviour of CM (low elastic modulus and high strain values) can be assigned to the cutin. These results applied both to mature green and red ripe CM. Cutin elastic modulus, independently of the degree of temperature and hydration, was always significantly higher for the ripe than for the green samples while strain was lower; the amount of phenolics in the cutin network are the main candidates to explain the increased rigidity from mature green to red ripe cutin. The polysaccharide families isolated from CM were pectin, hemicellulose, and cellulose, the main polymers associated with the plant cell wall. The three types of polysaccharides were present in similar amounts in CM from mature green and red ripe tomatoes. Physical techniques such as X-ray diffraction and Raman spectroscopy indicated that the polysaccharide fibres were mainly randomly oriented. A tomato fruit CM scenario at the supramolecular level that could explain the observed CM biomechanical properties is presented and discussed. PMID:17975209

  13. FTIR Monitoring Of Curing Of Composites

    NASA Technical Reports Server (NTRS)

    Druy, Mark A.; Stevenson, William A.; Young, Philip R.

    1990-01-01

    Infrared-sensing optical fiber system developed to monitor principal infrared absorption bands resulting from vibrations of atoms and molecules as chemical bonds form when resin cured. System monitors resin chemistry more directly. Used to obtain Fourier transform infrared (FTIR) spectrum from graphite fiber/polyimide matrix resin prepreg. Embedded fiber optic FTIR sensor used to indicate state of cure of thermosetting composite material. Developed primarily to improve quality of advanced composites, many additional potential applications exist because principal of operation applicable to all organic materials and most inorganic gases. Includes monitoring integrities of composite materials in service, remote sensing of hazardous materials, and examination of processes in industrial reactors and furnaces.

  14. Tunable diode lasers as a tool for conformational control: the case of matrix-isolated oxamic acid.

    PubMed

    Halasa, Anna; Lapinski, Leszek; Rostkowska, Hanna; Reva, Igor; Nowak, Maciej J

    2015-03-19

    A tunable diode laser was applied as a source of narrowband near-infrared light used to manipulate the structure of the molecule of oxamic acid. Monomers of the most stable conformer I of the molecule, with the trans orientation of the O═COH group and the trans orientation of the O═CC═O fragment, were trapped from the gas phase in low-temperature argon, neon, and nitrogen matrixes. Monomers of oxamic acid, isolated in argon or neon matrixes, were then irradiated with narrowband near-IR light from the diode laser tuned at 6833 (Ar) or 6840 cm(-1) (Ne). Upon such irradiation another conformer, II, of oxamic acid was generated, with cis orientation of the O═COH group and trans orientation of the O═CC═O fragment. Both forms were identified by comparison of their experimental mid-IR spectra with the spectra theoretically calculated for I and II. Subsequent irradiation of the matrix at 6940 (Ar) or 6991 cm(-1) (Ne), where absorption appeared in the near-IR spectrum of the photoproduct, led to photoconversion of conformer II into form I. In a series of subsequent irradiations at 6833(Ar)/6840(Ne) cm(-1) and at 6940(Ar)/6991(Ne) cm(-1), the population of oxamic acid molecules was selectively shifted several times from I to II and vice versa. As far as we know, this is the first reported study where a tunable diode laser source of narrowband near-IR light was used to manipulate the structure of a molecule. Spontaneous II → I transformation was observed for Ne and Ar matrixes kept in the dark and at cryogenic temperature. PMID:24611466

  15. H-Bonding of Sulfuric Acid with Its Decomposition Products: An Infrared Matrix Isolation and Computational Study of the H2SO4·H2O·SO3 Complex.

    PubMed

    Rozenberg, Mark; Loewenschuss, Aharon; Nielsen, Claus J

    2016-05-26

    The FTIR matrix isolation spectra of H2SO4 vapors show a group of bands with synchronous growth of their relative intensities which is independent of the water species content of the matrix layer. Their frequency positions indicate that the species they represent is H-bonded and composed of all three components (H2SO4, H2O, and SO3) involved in the vapor decomposition equilibrium of the acid molecule. Structure, stabilization energies, and vibrational frequencies of several H-bonded complexes between these components were considered in B3LYP calculations employing Dunning's correlation-consistent aug-cc-pVTZ basis sets. Correlations between spectral shifts, bond lengths, and H-bond energies were also considered. The best fitting complex is a ring structured 1:1:1 H2SO4·H2O·SO3. The indications are that the complex is formed in the vapor phase and not after deposition. The atmospheric significance may be in its ability to serve as a H-bonding nucleation center even without the presence of additional contaminants. PMID:27135379

  16. Adhesion to hyphal matrix and antifungal activity of Pseudomonas strains isolated from Tuber borchii ascocarps.

    PubMed

    Sbrana, C; Bagnoli, G; Bedini, S; Filippi, C; Giovannetti, M; Nuti, M P

    2000-03-01

    Pseudomonas spp. isolates from Tuber borchii ascocarps, known to be able to produce phytoregulatory and biocontrol substances in pure culture, were used to perform studies on their possible physiological role in nature. Antimycotic activity was confirmed against fungal contaminants isolated from the ascocarps, suggesting that populations associated with Tuber borchii fruit bodies may play a role in the maintenance of ascocarp health. Fifty-five percent of strains tested were also able to release metabolites which affected T. borchii mycelial growth and morphogenesis in culture. On the contrary, growth of the arbuscular mycorrhizal fungus Glomus mosseae and the ectomycorrhizal fungus Laccaria bicolor, putative competitors of Tuber for mycorrhizal infection sites on roots, was not influenced by the presence of any bacterial strain. The possibility that these bacteria, which show antifungal activity and fungal growth modulation activities, might be incorporated in the developing ascocarp by means of their preferential adhesion to Tuber mycelium is discussed. PMID:10749539

  17. Matrix-isolation and ab initio study of HKrCCCl and HXeCCCl

    SciTech Connect

    Zhu, Cheng; Räsänen, Markku; Khriachtchev, Leonid

    2015-12-28

    We report on two new noble-gas molecules, HKrCCCl and HXeCCCl, prepared in low-temperature Kr and Xe matrices. These molecules are made by UV photolysis of HCCCl in the matrices and subsequent thermal annealing. The HCCCl precursor is produced by microwave discharge of a mixture of a matrix gas with trichloroethylene (HClC=CCl{sub 2}). The assignments of the new noble-gas molecules are supported by deuteration experiments and quantum chemical calculations at the MP2(full) and CCSD(T) levels of theory with the def2-TZVPPD basis set. No evidence of ClXeCCH, which is computationally reliably stable, is found in the experiments. ClKrCCH as well as the Ar compounds HArCCCl and ClArCCH are not observed either, which is in agreement with the calculations.

  18. Infrared spectra, photochemistry, and ab initio calculations of matrix isolated methanethiol/sulfur dioxide complex

    NASA Astrophysics Data System (ADS)

    Li, S.; Kurtz, H.; Korambath, P.; Li, Y.-S.

    2000-09-01

    Intermolecular complexes of methanethiol with sulfur dioxide have been prepared by condensing the reagents diluted in argon and in nitrogen at 12-14 K. The 1:1 CH 3SH/SO 2 complexes were identified from the infrared spectra of the mixtures of methanethiol with sulfur dioxide in argon and nitrogen matrices. Perturbations to the vibrational energy spaces of some vibrational modes were identified and assigned. Ab initio calculations with the 6-311G ∗∗ basis set have been performed to get some information about the structure, binding energy, dipole moment, and potential function governing the internal rotation of SO 2 for the complex. The calculated results have suggested that the dipole/dipole interaction held the constituent species together to form the complex. Photochemical reactions were performed by exposing the matrix mixtures to UV irradiation. The appearance of new bands indicated the presence of more than one photochemical reaction product.

  19. Matrix-isolated infrared absorption spectrum of CH2BrOO radical

    NASA Astrophysics Data System (ADS)

    Zhang, Xu; Sander, Stanley P.; Cheng, Lan; Thimmakondu, Venkatesan S.; Stanton, John F.

    2016-07-01

    The bromomethylperoxy radical, CH2BrOO, has been generated in cryogenic matrices. Six fundamental bands for CH2BrOO have been observed in an argon matrix at 5 K. The experimental frequencies (cm-1) are: ν4 = 1274.3, ν5 = 1229.4, ν6 = 1086.7, ν7 = 961.8, ν8 = 879.9, and ν10 = 515.4, two of which are detected for the first time. Ab initio calculations have been performed employing coupled-cluster methods. The experimental frequencies are shown to be in good agreement with the computation as well as the four bands (ν4, ν6, ν7 and ν8) observed by Huang and Lee in the gas phase.

  20. Investigation of the mechanism of ozonolysis of (Z)-3-methyl-2-pentene using matrix isolation infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Coleman, Bridgett E.; Ault, Bruce S.

    2013-01-01

    The matrix isolation technique, combined with infrared spectroscopy and twin jet codeposition, has been used to characterize intermediates and stable "late" products formed during the ozonolysis of (Z)-3-methyl-2-pentene (MP). While twin jet deposition led to minimal product formation, annealing to 35 K produced a number of product bands. Based on isotopic labeling and theoretical calculations, product bands have been assigned to the primary ozonide and also tentatively to the secondary ozonide of MP. Indirect evidence for formation of one or both possible Criegee intermediates in this system is presented. While neither possible Criegee intermediate for this system was observed, the evidence overall clearly supports the mechanism first proposed by Criegee for the ozonolysis of alkenes. UV irradiation led to product arising from O atom addition to MP, while merged jet codeposition led to a number of stable products for this system.

  1. Combined matrix isolation IR spectroscopic and ab initio quantum chemical study of the molecular structure of aminomethylphosphinic acid

    NASA Astrophysics Data System (ADS)

    Stepanian, S. G.; Reva, I. D.; Radchenko, E. D.; Latajka, Z.; Wierzejewska, M.; Ratajczak, H.

    1999-06-01

    The molecular structure of 1-methylaminophosphinic acid (AMPA) was investigated with the matrix isolation IR spectroscopy and ab initio calculations performed with RHF, MP2, MP3, MP4(DQ), MP4(SDQ) and MP4(SDTQ) methods. Three pseudopotential basis sets designed as CEP-31G were used in the calculations: Basis Set I-CEP-31G with the d-functions on phosphorus; Basis Set II-CEP-31G with the d-functions on all heavy atoms; Basis Set III-CEP-31G with the d-functions on all heavy atoms and p-functions on hydrogens. Four stable molecular and four stable zwitterion conformers of aminophosphinic acid were found via ab initio calculations. According to the calculations, molecular conformers are always more stable than the zwitterion conformers, irrespective of the basis set size and level of theory. This result is in good agreement with matrix IR spectrum of the AMPA. The presence of the bands of OH stretching and NH 2 bending vibrations and the absence of the bands of POO - and NH 3+ vibrations are the evidence of molecular structure of AMPA in the isolated state. An increased number of vibrational bands is found in the IR spectrum. It is explained by the high conformation lability of AMPA molecules which is related to very low barrier of rotation about C-P bond. The IR spectrum is actually determined by multiple sites of AMPA molecule packed in the Ar crystal, which considerably increases the number of bands in the IR spectrum.

  2. Further characterization of ATP-initiated calcification by matrix vesicles isolated from rachitic rat cartilage. Membrane perturbation by detergents and deposition of calcium pyrophosphate by rachitic matrix vesicles.

    PubMed

    Hsu, H H; Camacho, N P; Anderson, H C

    1999-01-12

    Although membrane associated enzymes such as ATPase, alkaline phosphatase, and NTP pyrophosphohydrolase in matrix vesicles (MVs) may underlie the mechanisms of ATP-promoted calcification, prior to the current investigation, the role of the MV membrane in calcification had not been addressed. In this study, various perturbations were introduced to the MV membrane in in vitro calcification systems to determine ideal conditions for ATP-initiated calcification by MVs isolated from rachitic rat epiphyseal cartilage. Membrane integrity appears to be required, since the rupture of the vesicular membrane by vigorously mixing with 10% butanol abolished calcification. In contrast, a mild treatment of MVs with low concentrations (e.g., 0.01%, which is much below the critical concentration for micelle formation) of either neutral Triton X-100 or anionic deoxycholate stimulated calcification by >2-fold, without inducing obvious changes in vesicular appearance. Fourier transform infrared spectroscopic studies were done to identify the mineral phase formed in these experiments. For the first time, rachitic MVs were shown to induce the formation of a calcium pyrophosphate dihydrate-like phase after their exposure to calcifying medium with 1 mM ATP. The integration of spectral areas indicated that calcification was enhanced by Triton X-100. The detergent effect was reversible and appeared to be not mediated through activation of ATPase, alkaline phosphatase, or ATP pyrophosphohydrolase. In contrast to neutral Triton X-100 and anionic deoxycholate, cationic cetyltrimethylammonium bromide inhibited both ATPase activity (I50=10 microM) and ATP-initiated calcification. These observations suggest that membrane perturbations can affect calcification and that the presence of NTP-pyrophosphohydrolase in MVs may play a role in the deposition of CaPPi in rachitic cartilage. PMID:9889389

  3. Matrix isolation study of the ozonolysis of 1,3- and 1,4-cyclohexadiene: identification of novel reaction pathways.

    PubMed

    Pinelo, Laura; Gudmundsdottir, Anna D; Ault, Bruce S

    2013-05-23

    The ozonolysis reactions of 1,3- and 1,4-cyclohexadiene have been studied using a combination of matrix isolation, infrared spectroscopy, and theoretical calculations. Experimental and theoretical results demonstrate that these reactions predominantly do not follow the long-accepted Criegee mechanism. Rather, the reaction of O3 with 1,4-cyclohexadiene leads to the essentially barrierless formation of benzene, C6H6, and H2O3. These two species are then trapped in the same argon matrix cage and weakly interact to form a molecular complex. There is also evidence for the formation of a small amount of the primary ozonide as a minor product, formed through a transition state that is slightly higher in energy. The reaction of O3 with 1,3-cyclohexadiene follows two pathways, one of which is the Criegee mechanism through a low energy transition state leading to formation of the primary ozonide. In addition, with a similar barrier, ozone abstracts a single hydrogen from C5 while adding to C1, forming a hydroperoxy intermediate. This study presents two of the rare cases in which the Criegee mechanism is not the dominant pathway for the ozonolysis of an alkene as well as the first evidence for dehydrogenation of an alkene by ozone. PMID:23638640

  4. Infrared matrix isolation and theoretical study of the initial intermediates in the reaction of ozone with cycloheptene

    NASA Astrophysics Data System (ADS)

    Pinelo, Laura; Ault, Bruce S.

    2012-10-01

    Matrix isolation combined with infrared spectroscopy resulted in the observation of early intermediates in the reaction of two conformers of cycloheptene and ozone, marking the first observation of these intermediates for a cyclic alkene with conformational isomerism. Spectral evidence supports the presence of the primary ozonide of the chair and boat conformers of cis-cycloheptene, which represents the first time two primary ozonide isomers have been observed for any alkene. In addition, at least one conformer of the Criegee intermediate formed through ring-opening of the cyclic primary ozonide, as well as stable end products. Both the Criegee intermediate and primary ozonide were observed in the spectra of the initial deposition in twin jet experiments. After the matrix was annealed to 36 K, peaks of the primary ozonide increased by ˜250% while the peak of the Criegee intermediate increased by ˜150%. Supporting data was obtained from 18O-labeled ozone experiments. In addition to experimental evidence, further justification was provided by theoretical calculations at the B3LYP/6-311++G(d,2p) level. The photochemical reactions of the trapped species were also studied. After irradiation of the secondary ozonide and stable products of the ozonolysis reaction, 1-hexanal and carbon dioxide were observed. Late, stable oxidation products of cycloheptene were observed in merged jet experiments.

  5. Infrared study of matrix-isolated ethyl cyanide: simulation of the photochemistry in the atmosphere of Titan.

    PubMed

    Toumi, A; Piétri, N; Couturier-Tamburelli, I

    2015-11-11

    Low-temperature Ar matrix isolation has been carried out to investigate the infrared spectrum of ethyl cyanide (CH3CH2CN), a molecule present in the atmosphere of Titan. The λ > 120 nm and λ > 230 nm photolysis reactions of ethyl cyanide in an Ar matrix were also performed in order to compare the behaviour of this compound when it is submitted to high and low energetic radiations. These different wavelengths have been used with the aim to reproduce the radiation reaching the various parts of the atmosphere. Several photoproducts have been identified during photolysis such as vinyl cyanide (CH2[double bond, length as m-dash]CHCN), cyanoacetylene (HC3N), and ethylene/hydrogen cyanide (C2H4/HCN), ethylene/hydrogen isocyanide (C2H4/HNC), acetylene/hydrogen cyanide (C2H2/HCN), acetylene/hydrogen isocyanide (C2H2/HNC), and acetylene:methylenimine (C2H2:HNCH2) complexes. Ethyl isocyanide (CH3CH2NC) and a ketenimine form (CH3CH[double bond, length as m-dash]C[double bond, length as m-dash]NH) have been identified as well. Photoproduct identification and spectral assignments were done using previous studies and density functional theory (DFT) calculations with the B3LYP/cc-pVTZ basis set. PMID:26507585

  6. A Fibrin Matrix Promotes the Differentiation of EMSCs Isolated from Nasal Respiratory Mucosa to Myelinating Phenotypical Schwann-Like Cells

    PubMed Central

    Chen, Qian; Zhang, Zhijian; Liu, Jinbo; He, Qinghua; Zhou, Yuepeng; Shao, Genbao; Sun, Xianglan; Cao, Xudong; Gong, Aihua; Jiang, Ping

    2015-01-01

    Because Schwann cells perform the triple tasks of myelination, axon guidance and neurotrophin synthesis, they are candidates for cell transplantation that might cure some types of nervous-system degenerative diseases or injuries. However, Schwann cells are difficult to obtain. As another option, ectomesenchymal stem cells (EMSCs) can be easily harvested from the nasal respiratory mucosa. Whether fibrin, an important transplantation vehicle, can improve the differentiation of EMSCs into Schwann-like cells (SLCs) deserves further research. EMSCs were isolated from rat nasal respiratory mucosa and were purified using anti-CD133 magnetic cell sorting. The purified cells strongly expressed HNK-1, nestin, p75NTR, S-100, and vimentin. Using nuclear staining, the MTT assay and Western blotting analysis of the expression of cell-cycle markers, the proliferation rate of EMSCs on a fibrin matrix was found to be significantly higher than that of cells grown on a plastic surface but insignificantly lower than that of cells grown on fibronectin. Additionally, the EMSCs grown on the fibrin matrix expressed myelination-related molecules, including myelin basic protein (MBP), 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) and galactocerebrosides (GalCer), more strongly than did those grown on fibronectin or a plastic surface. Furthermore, the EMSCs grown on the fibrin matrix synthesized more neurotrophins compared with those grown on fibronectin or a plastic surface. The expression level of integrin in EMSCs grown on fibrin was similar to that of cells grown on fibronectin but was higher than that of cells grown on a plastic surface. These results demonstrated that fibrin not only promoted EMSC proliferation but also the differentiation of EMSCs into the SLCs. Our findings suggested that fibrin has great promise as a cell transplantation vehicle for the treatment of some types of nervous system diseases or injuries. PMID:25666351

  7. Conformational distortion of α-phenylethyl amine in cryogenic matrices - a matrix isolation VCD study.

    PubMed

    Pollok, Corina H; Merten, Christian

    2016-05-21

    The chiral amine α-phenylethyl amine (PEA) was isolated in cryogenic matrices and investigated using vibrational circular dichroism (VCD) and infrared spectroscopy. The potential energy surface (PES) of PEA features five different conformers connected by relatively low conformational transition states. Based on the IR spectra, it could be confirmed that all conformational energy barriers are passed at a deposition temperature of 20 K, and that only the global minimum conformation of PEA is populated in both argon and nitrogen matrices. However, differences in the calculated and experimental VCD spectra indicate deviations from the minimum structure by perturbation of the phenyl ring as well as of the amine orientation. The degree of the perturbation is found to also depend on the choice of the host gas, which shows the subtle influence of the environment on the conformational distortion of PEA. PMID:27125494

  8. Matrix isolation infrared spectroscopic and theoretical study of 1,1,1-trifluoro-2-chloroethane (HCFC-133a)

    SciTech Connect

    Rodrigues, Gessenildo Pereira; Ventura, Elizete E-mail: rfausto@ci.uc.pt; Andrade do Monte, Silmar; Lucena, Juracy Régis; Reva, Igor; Fausto, Rui E-mail: rfausto@ci.uc.pt

    2013-11-28

    The molecular structure and infrared spectrum of the atmospheric pollutant 1,1,1-trifluoro-2-chloroethane (HCFC-133a; CF{sub 3}CH{sub 2}Cl) in the ground electronic state were characterized experimentally and theoretically. Excited state calculations (at the CASSCF, MR-CISD, and MR-CISD+Q levels) have also been performed in the range up to ∼9.8 eV. The theoretical calculations show the existence of one (staggered) conformer, which has been identified spectroscopically for the monomeric compound isolated in cryogenic (∼10 K) argon and xenon matrices. The observed infrared spectra of the matrix-isolated HCFC-133a were interpreted with the aid of MP2/aug-cc-pVTZ calculations and normal coordinate analysis, which allowed a detailed assignment of the observed spectra to be carried out, including identification of bands due to different isotopologues ({sup 35}Cl and {sup 37}Cl containing molecules). The calculated energies of the several excited states along with the values of oscillator strengths and previous results obtained for CFCs and HCFCs suggest that the previously reported photolyses of the title compound at 147 and 123.6 nm [T. Ichimura, A. W. Kirk, and E. Tschuikow-Roux, J. Phys. Chem. 81, 1153 (1977)] are likely to be initiated in the n-4s and n-4p Rydberg states, respectively.

  9. A Novel Compound Rasatiol Isolated from Raphanus sativus Has a Potential to Enhance Extracellular Matrix Synthesis in Dermal Fibroblasts

    PubMed Central

    Roh, Seok-Seon; Park, Seung-Bae; Park, Seong-Mo; Choi, Byoung Wook; Lee, Min-Ho; Hwang, Yul-Lye; Kim, Chang Hun; Jeong, Hyun-Ah; Kim, Chang Deok

    2013-01-01

    Background The fibrous proteins of extracellular matrix (ECM) produced by dermal fibroblast contributes to the maintenance of connective tissue integrity. Objective This study is carried out to identify the bioactive ingredient from natural products that enhances ECM production in dermal fibroblasts. Methods Bioassay-directed fractionation was used to isolate the active ingredient from natural extracts. The effects of rasatiol (isolated from Raphanus sativus) on ECM production in primary cultured human dermal fibroblasts was investigated by enzyme linked immunosorbent assay and western blot analysis. Results Rasatiol accelerated fibroblast growth in a dose-dependent manner and increased the production of type 1 collagen, fibronectin and elastin. Phosphorylation of p42/44 extracellular signal-regulated kinase, p38 mitogen-activated protein kinase, and Akt was remarkably increased by rasatiol, indicating that enhanced ECM production is linked to the activation of intracellular signaling cascades. Conclusion These results indicate that rasatiol stimulates the fibrous components of ECM production, and may be applied to the maintenance of skin texture. PMID:24003274

  10. Matrix solid-phase dispersion (MSPD) isolation and liquid chromatographic determination of oxytetracycline, tetracycline, and chlortetracycline in milk.

    PubMed

    Long, A R; Hsieh, L C; Malbrough, M S; Short, C R; Barker, S A

    1990-01-01

    A multiresidue method for the isolation and liquid chromatographic determination of oxytetracycline (OTC), tetracycline (TC), and chlortetracycline (CTC) antibiotics in milk is presented. Blank and tetracycline (OTC, TC, and CTC) fortified milk samples (0.5 mL) were blended with octadecylsilyl (C18, 40 microns, 18% load, endcapped, 2 g) derivatized silica packing material containing 0.05 g each of oxalic acid and disodium ethylenediaminetetraacetic. A column made from the C18/milk matrix was first washed with hexane (8 mL), following which the tetracyclines were eluted with ethyl acetate-acetonitrile (1 + 3; v/v). The eluate contained tetracycline analytes that were free from interfering compounds when analyzed by liquid chromatography with UV detection (photodiode array, 365 nm). Correlation coefficients of standards curves for individual tetracycline isolated from fortified samples were linear (from 0.982 +/- 0.009 to 0.996 +/- 0.004) with average percentage recoveries from 63.5 to 93.3 for the concentration range (100, 200, 400, 800, 1600, and 3200 ng/mL) examined. The inter-assay variability ranged from 8.5 +/- 2.4% to 20.7 +/- 13.0% with an intra-assay variability of 1.0-9.3%. PMID:2115861

  11. Heavy atom effect on magnetic anisotropy of matrix-isolated monobromine substituted septet trinitrene.

    PubMed

    Misochko, Eugenii Ya; Masitov, Artem A; Akimov, Alexander V; Korchagin, Denis V; Chapyshev, Sergei V

    2015-03-19

    The heavy atom effect on the magnetic anisotropy of septet trinitrenes is reported. Septet 1-bromo-3,5-dichloro-2,4,6-trinitrenobenzene (S-1) was generated in a solid argon matrix by ultraviolet irradiation of 1,3,5-triazido-2-bromo-4,6-dichlorobenzene. This trinitrene displays an electron spin resonance (ESR) spectrum that drastically differs from ESR spectra of all previously studied septet trinitrenes. The zero-field splitting (ZFS) parameters, derived from the experimental spectrum, show the parameter |D| = 0.1237 cm(-1) and the unprecedentedly large ratio of E/D = 0.262 that is close to the rhombic limit E/D = 1/3 for high-spin molecules. The CASCI (based on state-averaged CASSCF) and DFT methods were applied to calculate the ZFS tensor focusing on the heavy (bromine) atom effects on the spin-orbit term. These calculations show that the multiconfigurational ab initio formalism and the CASCI method are the most successful for accurate predictions of the spin-orbit term in the ZFS tensor of high-spin nitrenes containing heavy bromine atoms. Due to the presence of the bromine atom in S-1, the contribution of the spin-orbit term to the total parameter D is dominant and responsible for the unusual orientation of the easy Z-axis lying in the molecular plane perpendicular to the C-Br bond. As a result, the principal values D(XX), D(YY), and D(ZZ) of the total tensor D̂(Tot) have such magnitudes and signs for which the ratio E/D is close to the rhombic limit, and the total parameter D is large in magnitude and positive in sign. PMID:25350487

  12. Vibrational relaxation of matrix-isolated CH/sub 3/F and HCl

    SciTech Connect

    Young, L.

    1981-08-01

    Kinetic and spectroscopic studies have been performed on CH/sub 3/F and HCl as a function of host matrix and temperature. Temporally and spectrally resolved infrared fluorescence was used to monitor the populations of both the initially excited state and the lower lying levels which participate in the relaxation process. For CH/sub 3/F, relaxation from any of the levels near 3.5 ..mu.., i.e. the CH stretching fundamentals or bend overtones, occurs via rapid (< 5 ns) V ..-->.. V transfer to 2..nu../sub 3/ with subsequent relaxation of the ..nu../sub 3/ (CF stretch) manifold. Lifetimes of 2..nu../sub 3/ and ..nu../sub 3/ were determined through overtone, ..delta..V = 2, and fundamental fluorescence. These lifetimes show a dramatic dependence on host lattice, an increase of two orders of magnitude in going from Xe and Ar matrices. Lifetimes depend only weakly on temperature. The relaxation of 2..nu../sub 3/ and ..nu../sub 3/ is consistent with a model in which production of a highly rotationally excited guest via collisions with the repulsive wall of the host is the rate limiting step. For HCl, lifetimes of v = 1,2,3 have been determined. In all hosts, the relaxation is non-radiative. For a given vibrational state, v, the relaxation rate increases in the series k(Ar) < k(Kr) < k(Xe). The dependence of the relaxation rate; on v is superlinear in all matrices, the deviation from linearity increasng in the order Ar < Kr < Xe. The relaxation rates become more strongly temperature dependent with increasing vibrational excitation. The results are consistent with a mechanism in which complex formation introduces the anisotropy necessary to induce a near resonant V ..-->.. R transition in the rate limiting step.

  13. Quantitative mineralogical applications of FTIR

    SciTech Connect

    Malatesta, A.S.; Dohmann, C.Y.; Ferrell, R.E. Jr.; Leblanc, W.S. . Dept. of Geology and Geophysics); Wood, M.L. . Dept. of Geosciences); Williams, L.B. . Dept. of Geology)

    1993-03-01

    FTIR (Fourier Transform Infrared) spectroscopy techniques can be applied to the quantitative estimation of mineral abundances. The method is particularly useful for minerals with unique absorption bands such as those due to OH-stretching in the clay minerals. Overlapping bands, scarcity of standards, and difficulties of sample preparation are the most serious drawbacks of the method. More than 20 clay-mineral separates (< 2[mu]m) from the Wilcox Fm. of central La. were analyzed by XRD procedures and used as the basis for assessing an FTIR method employing the areas of absorbance bands after decomposition and background subtraction. Samples were ground in alcohol, dried and analyzed (in triplicate) as pellets containing 2 mg of clay per 200mg of KBr. Peaks considered in the quantitative analysis included those at wavenumbers 3,697, 3,668, 3,653, 3,637, 3,622, 3,603, 3,447, and 1,635 cm[sup [minus]1]. Kaolinite is the most abundant clay mineral ranging from 30-83 wt.% by XRD with a mean of 75 wt.% and a stand. dev. of 13 wt.%. The remainder of the clay fraction is composed of illite, an I/S, and a chlorite. The initial quantitative approach was to calculate the correlation coefficient for the matrix of absorbances and XRD estimates of mineral abundances. Kaolinite and the band at 3,697 cm[sup [minus]1] produced a correlation coefficient of 0.797. A curve relating wt.% kaolinite (y) to absorbance (x) had the form: y = [minus]64 + 190x [minus] 63x[sup 2]. The difference between the measured and predicted values was < 10 wt.% within the abundance range investigated.

  14. Comparison of Colony Hybridization to Phenotype Screening on Washed Sheep's Blood Agar for the Isolation of Shiga toxin Producing Escherichia coli from Complex Matrixes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Purpose of study: Isolating Shiga toxin-producing Escherichia coli (STEC) from complex matrixes such as ground beef is a lengthy and laborious process. In our previous studies of STEC present in beef production, colony hybridization was used to identify suspect stx containing colonies for further c...

  15. Antimicrobial activities and matrix-assisted laser desorption/ionization mass spectrometry of Bacillus isolates from the marine sponge Aplysina aerophoba.

    PubMed

    Pabel, Christian T; Vater, Joachim; Wilde, Christopher; Franke, Peter; Hofemeister, Jürgen; Adler, Barbara; Bringmann, Gerhard; Hacker, Jörg; Hentschel, Ute

    2003-01-01

    The aim of this study was to isolate bacteria that are resistant to the strong antimicrobial metabolites characteristic of Aplysina aerophoba. For this purpose, bacterial isolation was performed on agar plates to which sponge tissue extract had been added. Following screening for antifungal and antimicrobial activities, 5 strains were chosen for more detailed analyses. 16S ribosomal DNA sequencing revealed that all isolates belonged to the genus Bacillus, specifically B. subtilis and B. pumilus. Using a combination of matrix-assisted laser desorption/ ionization mass spectrometry typing of whole cells and antimicrobial bioassays against selected reference strains, the bioactive metabolites were identified as lipopeptides. PMID:14730425

  16. Matrix solid phase dispersion assisted enzymatic hydrolysis as a novel approach for cocaine and opiates isolation from human hair.

    PubMed

    Míguez-Framil, Martha; Cabarcos, Pamela; Tabernero, María Jesús; Bermejo, Ana María; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

    2013-11-01

    The possibility of assisting enzymatic hydrolysis (EH) procedures by sample disruption mechanisms inherent to matrix solid phase dispersion (MSPD) has been explored in the current study. EH of hair specimens from poly-drug abusers was assisted by dispersing/blending the sample (0.05 g) with alumina (2.25 g) before loading the dissolved enzyme (6 mL of 1 mg mL(-1) Pronase E in 1.4 M/1.4 M Tris/HCl, pH 7.3) through the hair-alumina solid phase packaged inside a disposable MSPD syringe. The MSPD-EH method was developed, and it proved to offer quantitative results when isolating cocaine, benzoylecgonine (BZE), codeine, morphine and 6-monoacethylmorphine (6-MAM) from human hair samples. The procedure allows an on column clean-up/pre-concentration procedure of the isolated targets by attaching a previously conditioned Oasis HLB cartridge to the end of the MSPD syringe. The EH procedure of human hair with Pronase E can therefore be shortened to approximately 30 min. Within this time, sample blending/dispersion, MSPD syringe package, elution (EH when dissolved Pronase E is passing through the sample-dispersant bed), and extract clean-up and target pre-concentration stages are achieved. Gas chromatography-mass spectrometry (GC-MS) was used for determining each target after elution from the Oasis HLB cartridges with 2 mL of 2% (v/v) acetic acid in methanol, concentration by N2 stream evaporation, and dried extract derivatization with N-methyl-tert-butylsilyltrifluoroacetamide (BSTFA) and chlorotrimethylsilane (TMCS). The method was validated according to the guidance for bioanalytical method validation of the US Department of Health and Human Services, Food and Drug Administration. The simplicity of the proposed approach makes it a useful procedure for screening/quantifying drugs of abuse in hair specimens from poly-drug abusers. PMID:24112826

  17. ATR-FTIR Spectroscopy Highlights the Problem of Distinguishing Between Exophiala dermatitidis and E. phaeomuriformis Using MALDI-TOF MS.

    PubMed

    Ergin, Çağrı; Gök, Yaşar; Bayğu, Yasemin; Gümral, Ramazan; Özhak-Baysan, Betil; Döğen, Aylin; Öğünç, Dilara; Ilkit, Macit; Seyedmousavi, Seyedmojtaba

    2016-02-01

    The present study compared two chemical-based methods, namely, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, to understand the misidentification of Exophiala dermatitidis and Exophiala phaeomuriformis. The study utilized 44 E. dermatitidis and 26 E. phaeomuriformis strains, which were partially treated with strong acids and bases for further evaluation. MALDI-TOF MS and ATR-FTIR spectroscopy data of the two Exophiala species were compared. Data groupings were observed for the chromic acid- and nitric acid-treated species when the black yeast sources were categorized as creosoted-oak sleepers, concrete sleepers, or dishwasher isolates. The MALDI-TOF MS data for the metalloenzyme-containing regions were consistent with the ATR-FTIR spectroscopy data. These results indicated that environmental isolates might contain metals not found in human isolates and might interfere with chemical-based identification methods. Therefore, MALDI-TOF MS reference libraries should be created for clinical strains and should exclude petroleum-associated environmental isolates. PMID:26373644

  18. UV and VUV spectrum of matrix-isolated In: an investigation by absorption, magnetic circular dichroism and emission yield spectroscopy

    NASA Astrophysics Data System (ADS)

    Schroeder, W.; Rotermund, H.-H.; Wiggenhauser, H.; Schrittenlacher, W.; Hormes, J.; Krebs, W.; Laaser, W.

    1986-05-01

    The electronic absorption spectra of In atoms isolated in neon, argon, krypton and xenon matrices have been measured in the energy range between 2.5 and 9.0 eV. This region includes the 5s 25p → 5s 26s and 5s 25p → 5s 25d resonance transitions, higher members of the corresponding s- and d-Rydberg series and the inner shell 5s 25p → 5s5p 2 transitions. A correlation of the absorption spectra with results obtained from magnetic circular dichroism and fluorescence measurements has made it possible to provide a detailed assignment of most of the features in the spectra in spite of the complexities associated with their behavior. For example, the transition to 5s 26s could not be detected in any of the matrices and the 5s 25d configuration was found to be strongly quenched in intensity as compared to the other transitions. In contrast, several Rydberg transitions could be observed for In in Ne. These were satisfactorily interpreted within the Frenkel formalism. Some of these observations have been rationalized by assuming that the average radius of the wavefunction for the excited state is the dominant parameter for the matrix interaction.

  19. Matrix Isolation IR Spectroscopy of 1:1 Complexes of Acetic Acid and Trihaloacetic Acids with Water and Benzene

    NASA Astrophysics Data System (ADS)

    Banerjee, Pujarini; Chakraborty, Tapas

    2015-06-01

    A comparative study of infrared spectral effects for 1:1 complex formation of acetic acid (AA), trifluoroacetic acid (TFAA) and trichloroacetic acid (TFAA) with water and benzene has been carried out under a matrix isolation environment. Despite the large difference in aqueous phase acidities of the three acids, the measured νb{OH}stretching frequencies of the monomers of the three molecules are found to be almost same, and in agreement with gas phase electronic structure calculations. Intrinsic acidities are expressed only in the presence of the proton acceptors, water or benzene. Although electronic structure calculations predict distinct νb{OH} red-shifts for all three acids, the measured spectral features for TCAA and TFAA in this range do not allow unambiguous assignments for the 1:1 complex. On the other hand, the spectral changes in the νb{C=O} region are more systematic, and the observed changes are consistent with predictions of theory. Components of overall binding energy of each complex have been obtained from energy decomposition analysis, which allows determination of the relative contributions of various physical forces towards overall stability of the complexes, and the details will be discussed in the talk.

  20. Inbreeding avoidance, patch isolation and matrix permeability influence dispersal and settlement choices by male agile antechinus in a fragmented landscape.

    PubMed

    Banks, Sam C; Lindenmayer, David B

    2014-03-01

    Animal dispersal is highly non-random and has important implications for the dynamics of populations in fragmented habitat. We identified interpatch dispersal events from genetic tagging, parentage analyses and assignment tests and modelled the factors associated with apparent emigration and post-dispersal settlement choices by individual male agile antechinus (Antechinus agilis, a marsupial carnivore of south-east Australian forests). Emigration decisions were best modelled with on data patch isolation and inbreeding risk. The choice of dispersal destination by males was influenced by inbreeding risk, female abundance, patch size, patch quality and matrix permeability (variation in land cover). Males were less likely to settle in patches without highly unrelated females. Our findings highlight the importance of individual-level dispersal data for understanding how multiple processes drive non-randomness in dispersal in modified landscapes. Fragmented landscapes present novel environmental, demographic and genetic contexts in which dispersal decisions are made, so the major factors affecting dispersal decisions in fragmented habitat may differ considerably from unfragmented landscapes. We show that the spatial scale of genetic neighbourhoods can be large in fragmented habitat, such that dispersing males can potentially settle in the presence of genetically similar females after moving considerable distances, thereby necessitating both a choice to emigrate and a choice of where to settle to avoid inbreeding. PMID:23991826

  1. Experimental cell for molecular beam deposition and magnetic resonance studies of matrix isolated radicals at temperatures below 1 K

    SciTech Connect

    Sheludiakov, S. Ahokas, J.; Vainio, O.; Järvinen, J.; Zvezdov, D.; Vasiliev, S.; Khmelenko, V. V.; Mao, S.; Lee, D. M.

    2014-05-15

    We present the design and performance of an experimental cell constructed for matrix isolation studies of H and D atoms in solid H{sub 2}/D{sub 2} films, which are created by molecular beam deposition at temperatures below 1 K. The sample cell allows sensitive weighing of the films by a quartz microbalance (QM) and their studies by magnetic resonance techniques in a strong magnetic field of 4.6 T. We are able to regulate the deposition rate in the range from 0.01 to 10 molecular layers/s, and measure the thickness with ≈0.2 monolayer resolution. The upper QM electrode serves as a mirror for a 128 GHz Fabry-Perot resonator connected to an electron spin resonance (ESR) spectrometer. H and D atoms were created by RF discharge in situ in the sample cell, and characterized by ESR and electron-nuclear double resonance. From the magnetic resonance measurements we conclude that the films are smooth and provide homogeneous trapping conditions for embedded atoms. The current sample cell design also makes it possible to calibrate the ESR signal and estimate the average and local concentrations of H and D radicals in the film.

  2. UV irradiation study of a tripeptide isolated in an argon matrix: a tautomerism process evidenced by infrared and X-ray photoemission spectroscopies.

    PubMed

    Mateo-Marti, E; Pradier, C M

    2013-05-15

    Matrix isolation is a powerful tool for studying photochemical processes occurring in isolated molecules. In this way, we characterized the chemical modifications occurring within a tri peptide molecule, IGF, when exposed to the influence of Ultraviolet (UV) irradiation. This paper first describes the successful formation of the tripeptide (IGF) argon matrix under vacuum conditions, followed by the in situ UV irradiation and characterization of the molecular matrix reactivity after UV-irradiation. These studies have been performed by combining two complementary spectroscopic techniques, Fourier-Transform Reflexion Absorption Spectroscopy (FT-IRRAS) and X-ray Photoelectron Spectroscopy (XPS). The IR spectra of the isolated peptide-matrix, before and after UV irradiation, revealed significant differences that could be associated either to a partial deprotonation of the molecule or to a tautomeric conversion of some amide bonds to imide ones on some peptide molecules. XPS analyses undoubtedly confirmed the second hypothesis; the combination of IRRAS and XPS results provide evidence that UV irradiation of peptides induces a chemical reaction, namely a shift of the double bond, meaning partial conversion from amide tautomer into an imidic acid tautomer. PMID:23542515

  3. Molecular and phylogenetic analysis of matrix gene of avian influenza viruses isolated from wild birds and live bird markets in the USA

    PubMed Central

    Chander, Yogesh; Jindal, Naresh; Sreevatsan, Srinand; Stallknecht, David E.; Goyal, Sagar M.

    2012-01-01

    Please cite this paper as: Chander et al. (2012) Molecular and phylogenetic analysis of matrix gene of avian influenza viruses isolated from wild birds and live bird markets in the USA. Influenza and Other Respiratory Viruses 7(4), 513–520. Background  Wild birds are the natural hosts for influenza A viruses (IAVs) and provide a niche for the maintenance of this virus. Objectives  This study was undertaken to analyze nucleotide sequences of the matrix (M) gene of AIVs isolated from wild birds and live bird markets (LBMs) to index the changes occurring in this gene. Methods  M‐gene of 229 avian influenza virus (AIV) isolates obtained from wild birds and LBMs was amplified and sequenced. Full‐length sequences (∼900 nt.) thus obtained were analyzed to identify changes that may be associated with resistance to adamantanes. Phylogenetic analysis of all sequences was performed using clustalw, and evolutionary distances were calculated by maximum composite likelihood method using mega (ver. 5.0) software. Results  Twenty‐seven different viral subtypes were represented with H3N8 being the most dominant subtype in wild birds and H7N2 being the predominant subtype among isolates from LBMs. Phylogenetic analysis of the M‐gene showed a high degree of nucleotide sequence identity with US isolates of AIVs but not with those of Asian or European lineages. While none of the isolates from wild birds had any antiviral resistance–associated mutations, 17 LBM isolates carried polymorphisms known to cause reduced susceptibility to antiviral drugs (adamantanes). Of these 17 isolates, 16 had S31N change and one isolate had V27A mutation. Conclusions  These results indicate independent evolution of M‐gene in the absence of any antiviral drugs leading to mutations causing resistance indicating the need for continued active surveillance of AIVs. PMID:22958470

  4. Response of isolated rat liver mitochondria to variation of external osmolarity in KCl medium: regulation of matrix volume and oxidative phosphorylation.

    PubMed

    Devin, A; Guérin, B; Rigoulet, M

    1997-12-01

    When isolated rat liver mitochondria are incubated in KCI medium, matrix volume, flux, and forces in both hypo- and hyperosmolarity are time-dependent. In hypoosmotic KCl medium, matrix volume is regulated via the K+/H+ exchanger. In hyperosmotic medium, the volume is regulated in such a manner that at steady state, which is reached within 4 min, it is maintained whatever the hyperosmolarity. This regulation is Pi- and deltamuH+-dependent, indicating Pi-K salt entry into the matrix. Under steady state, hyperosmolarity has no effect on isolated rat liver mitochondria energetic parameters such as respiratory rate, proton electrochemical potential difference, and oxidative phosphorylation yield. Hypoosmolarity decreases the NADH/NAD+ ratio, state 3 respiratory rate, and deltamuH+, while oxidative phosphorylation yield is not significantly modified. This indicates kinetic control upstream the respiratory chain. This study points out the key role of potassium on the regulation of matrix volume, flux, and forces. Indeed, while matrix volume is regulated in NaCl hyperosmotic medium, flux and force restoration in hyperosmotic medium occurs only in the presence of external potassium. PMID:9559859

  5. Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Compounds and their Ions. 6; Polycyclic Aromatic Nitrogen Heterocycles

    NASA Technical Reports Server (NTRS)

    Mattioda, A. L.; Hudgins, Douglas M.; Bauschlicher, C. W., Jr.; Rosi, M.; Allamandola, L. J.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    The matrix-isolation technique has been employed to measure the mid-infrared spectra of several polycyclic aromatic nitrogen heterocycles in both neutral and cationic forms. The species studied include: 7,8 benzoquinoline (C13H9N); 2-azapyrene (C15H9N); 1- and 2-azabenz(a)anthracene (C17H11N); and 1-, 2-, and 4-azachrysene (also C17H11N). The experimentally measured band frequencies and intensities for each molecule are tabulated and compared with their theoretically calculated values computed using density functional theory at the B3LYP/4-31G level. The overall agreement between experiment and theory is quite good, in keeping with previous investigations involving the parent aromatic hydrocarbons. Several interesting spectroscopic trends are found to accompany nitrogen substitution into the aromatic framework of these compounds. First, for the neutral species, the nitrogen atom produces a significant increase in the total integrated infrared intensity across the 1600 - 1100/cm region and plays an essential role in the molecular vibration that underlies an uncharacteristically intense, discrete feature that is observed near 1400/cm in the spectra of 7,8 benzoquinoline, 1-azabenz(a)anthracene, and 4-azachrysene. The origin of this enhanced infrared activity and the nature of the new 1400/cm vibrational mode are explored. Finally, in contrast to the parent hydrocarbon species, these aromatic nitrogen heterocycles possess a significant permanent dipole moment. Consequently, these dipole moments and the rotational constants are reported for these species in their neutral and ionized forms.

  6. Does borazine-water behave like benzene-water? A matrix isolation infrared and ab initio study

    NASA Astrophysics Data System (ADS)

    Mishra, P.; Verma, K.; Bawari, D.; Viswanathan, K. S.

    2016-06-01

    Borazine is isoelectronic with benzene and is popularly referred to as inorganic benzene. The study of non-covalent interactions with borazine and comparison with its organic counterpart promises to show interesting similarities and differences. The motivation of the present study of the borazine-water interaction, for the first time, stems from such interesting possibilities. Hydrogen-bonded complexes of borazine and water were studied using matrix isolation infrared spectroscopy and quantum chemical calculations. Computations were performed at M06-2X and MP2 levels of theory using 6-311++G(d,p) and aug-cc-pVDZ basis sets. At both the levels of theory, the complex involving an N-H⋯O interaction, where the N-H of borazine serves as the proton donor to the oxygen of water was found to be the global minimum, in contrast to the benzene-water system, which showed an H-π interaction. The experimentally observed infrared spectra of the complexes corroborated well with our computations for the complex corresponding to the global minimum. In addition to the global minimum, our computations also located two local minima on the borazine-water potential energy surface. Of the two local minima, one corresponded to a structure where the water was the proton donor to the nitrogen of borazine, approaching the borazine ring from above the plane of the ring; a structure that resembled the global minimum in the benzene-water H-π complex. The second local minimum corresponded to an interaction of the oxygen of water with the boron of borazine, which can be termed as the boron bond. Clearly the borazine-water system presents a richer landscape than the benzene-water system.

  7. Does borazine-water behave like benzene-water? A matrix isolation infrared and ab initio study.

    PubMed

    Mishra, P; Verma, K; Bawari, D; Viswanathan, K S

    2016-06-21

    Borazine is isoelectronic with benzene and is popularly referred to as inorganic benzene. The study of non-covalent interactions with borazine and comparison with its organic counterpart promises to show interesting similarities and differences. The motivation of the present study of the borazine-water interaction, for the first time, stems from such interesting possibilities. Hydrogen-bonded complexes of borazine and water were studied using matrix isolation infrared spectroscopy and quantum chemical calculations. Computations were performed at M06-2X and MP2 levels of theory using 6-311++G(d,p) and aug-cc-pVDZ basis sets. At both the levels of theory, the complex involving an N-H⋯O interaction, where the N-H of borazine serves as the proton donor to the oxygen of water was found to be the global minimum, in contrast to the benzene-water system, which showed an H-π interaction. The experimentally observed infrared spectra of the complexes corroborated well with our computations for the complex corresponding to the global minimum. In addition to the global minimum, our computations also located two local minima on the borazine-water potential energy surface. Of the two local minima, one corresponded to a structure where the water was the proton donor to the nitrogen of borazine, approaching the borazine ring from above the plane of the ring; a structure that resembled the global minimum in the benzene-water H-π complex. The second local minimum corresponded to an interaction of the oxygen of water with the boron of borazine, which can be termed as the boron bond. Clearly the borazine-water system presents a richer landscape than the benzene-water system. PMID:27334162

  8. Matrix-isolated Al2OF6(2-) ion in molten and solid LiF/NaF/KF.

    PubMed

    Brooker, M H; Berg, R W; von Barner, J H; Bjerrum, N J

    2000-10-16

    A Raman spectrum consistent with that expected from an Al2OF6(2-) ion was observed when Na2O was dissolved in a eutectic LiF/NaF/KF (FLINAK) melt at 500 degrees C, which contained a low concentration of either AlF3 or Na3AlF6. Furthermore, it was possible to trap the Al2OF6(2-) ion in the frozen solid and to measure its Raman and IR spectra at 25 degrees C. A number of bands have been detected; among those, the two most characteristic bands of the Al2OF6(2-) ion at 494 (polarized) and 265 cm-1 in the FLINAK melt at 500 degrees C, and those at 509 and 268 (Raman) and approximately 780 to approximately 900 (IR) cm-1 for the compound matrix isolated in solid FLINAK at 25 degrees C. In the absence of added oxide, the dissolved aluminum fluoride was in the form of the octahedral AlF6(3-) ion, which has characteristic Raman bands at 542 and 325 cm-1 in the FLINAK melt at 500 degrees C. Whereas alumina, Al2O3, was found to be essentially insoluble in FLINAK melts, it was possible to dissolve sufficient amounts of Na2O to convert most of the AlF6(3-) to the oxyfluoroaluminate, Al2OF6(2-). These solutions appeared to be metastable with respect to formation of insoluble alumina at higher temperatures. The present results can be compared to previous measurements on alumina dissolved in pure molten cryolite at much higher temperatures, where alumina solubility is low and broad bands due to oxide species are difficult to detect due to overlap with bands from AlF6(3-) and AlF4-. PMID:11196946

  9. FTIR characterization of advanced materials

    NASA Technical Reports Server (NTRS)

    Young, P. R.; Chang, A. C.

    1986-01-01

    This paper surveys the application of Fourier transform infrared spectroscopy to the characterization of advanced materials. FTIR sampling techniques including internal and external reflectance and photoacoustic spectroscopy are discussed. Representative examples from the literature of the analysis of resins, fibers, prepregs and composites are reviewed. A discussion of several promising specialized FTIR techniques is also presented.

  10. Effects of Solid-Medium Type on Routine Identification of Bacterial Isolates by Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

    PubMed Central

    Anderson, Neil W.; Buchan, Blake W.; Riebe, Katherine M.; Parsons, Lauren N.; Gnacinski, Stacy

    2012-01-01

    Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) is a rapid method for the identification of bacteria. Factors that may alter protein profiles, including growth conditions and presence of exogenous substances, could hinder identification. Bacterial isolates identified by conventional methods were grown on various media and identified using the MALDI Biotyper (Bruker Daltonics, Billerica, MA) using a direct smear method and an acid extraction method. Specimens included 23 Pseudomonas isolates grown on blood agar, Pseudocel (CET), and MacConkey agar (MAC); 20 Staphylococcus isolates grown on blood agar, colistin-nalidixic acid agar (CNA), and mannitol salt agar (MSA); and 25 enteric isolates grown on blood agar, xylose lysine deoxycholate agar (XLD), Hektoen enteric agar (HE), salmonella-shigella agar (SS), and MAC. For Pseudomonas spp., the identification rate to genus using the direct method was 83% from blood, 78% from MAC, and 94% from CET. For Staphylococcus isolates, the identification rate to genus using the direct method was 95% from blood, 75% from CNA, and 95% from MSA. For enteric isolates, the identification rate to genus using the direct method was 100% from blood, 100% from MAC, 100% from XLD, 92% from HE, and 87% from SS. Extraction enhanced identification rates. The direct method of MALDI-TOF analysis of bacteria from selective and differential media yields identifications of varied confidence. Notably, Staphylococci spp. from CNA exhibit low identification rates. Extraction enhances identification rates and is recommended for colonies from this medium. PMID:22162546

  11. The matrix-isolated molecular complexes CO/XF (X=Cl,Br,I) and the molecular structure of FC(O)Br

    SciTech Connect

    Garcia, Placido; Willner, Helge; Oberhammer, Heinz; Francisco, Joseph S.

    2004-12-15

    FC(O)Br has been synthesized, and its IR spectrum in the gas phase and isolated in an Ar matrix, as well as, its Raman spectrum in the solid state at -196 deg. C has been analyzed. Its molecular structure has been determined and its UV has been measured. FC(O)Br and FC(O)Cl has been photodissociated in an argon matrix at 17 K with a 193 nm laser. The photolysis produces CO and XF which recombine to form CO/XF complexes. The formation of complexes are followed by the shift of the normal vibration modes with respect to CO and XF isolated in argon matrix. In the case of FC(O)Br, three isomers are identified, OC{center_dot}{center_dot}{center_dot}BrF, OC{center_dot}{center_dot}{center_dot}FBr, and CO{center_dot}{center_dot}{center_dot}BrF, whereas for FC(O)Cl only one isomer is observed, OC{center_dot}{center_dot}{center_dot}ClF. High level quantum chemical calculations are used to help the assignment of the different isomers.

  12. Advances in handheld FT-IR instrumentation

    NASA Astrophysics Data System (ADS)

    Arnó, Josep; Cardillo, Len; Judge, Kevin; Frayer, Maxim; Frunzi, Michael; Hetherington, Paul; Levy, Dustin; Oberndorfer, Kyle; Perec, Walter; Sauer, Terry; Stein, John; Zuidema, Eric

    2012-06-01

    FT-IR spectroscopy is the technology of choice to identify solid and liquid phase unknown samples. The challenges of ConOps (Concepts of Operation) in emergency response and military field applications require a significant redesign of the stationary FT-IR bench-top instruments typically used in laboratories. Specifically, field portable units require high levels of resistance against mechanical shock and chemical attack, ease of use in restrictive gear, quick and easy interpretation of results, and reduced size. In the last 20 years, FT-IR instruments have been re-engineered to fit in small suitcases for field portable use and recently further miniaturized for handheld operation. This article introduces the advances resulting from a project designed to overcome the challenges associated with miniaturizing FT-IR instruments. The project team developed a disturbance-corrected permanently aligned cube corner interferometer for improved robustness and optimized opto-mechanical design to maximize optical throughput and signal-to-noise ratios. Thermal management and heat flow were thoroughly modeled and studied to isolate sensitive components from heat sources and provide the widest temperature operation range. Similarly, extensive research on mechanical designs and compensation techniques to protect against shock and vibration will be discussed. A user interface was carefully created for military and emergency response applications to provide actionable information in a visual, intuitive format. Similar to the HazMatID family of products, state-of-the-art algorithms were used to quickly identify the chemical composition of complex samples based on the spectral information. This article includes an overview of the design considerations, tests results, and performance validation of the mechanical ruggedness, spectral, and thermal performance.

  13. Photochemistry of the ozone-water complex in cryogenic neon, argon, and krypton matrixes.

    PubMed

    Tsuge, Masashi; Tsuji, Kazuhide; Kawai, Akio; Shibuya, Kazuhiko

    2013-12-12

    The photochemistry of ozone-water complexes and the wavelength dependence of the reactions were studied by matrix isolation FTIR spectrometry in neon, argon, and krypton matrixes. Hydrogen peroxide was formed upon the irradiation of UV light below 355 nm. Quantitative analyses of the reactant and product were performed to evaluate the matrix cage effect of the photoreaction. In argon and krypton matrixes, a bimolecular O((1)D) + H2O → H2O2 reaction was found to occur to form hydrogen peroxide, where the O((1)D) atom generated by the photolysis of ozone diffused in the cryogenic solids to encounter water. In a neon matrix, hydrogen peroxide was generated through intracage photoreaction of the ozone-water complex, indicating that a neon matrix medium is most appropriate to study the photochemistry of the ozone-water complex. PMID:24252115

  14. Non-covalent C-Cl…π interaction in acetylene-carbon tetrachloride adducts: Matrix isolation infrared and ab initio computational studies.

    PubMed

    Ramanathan, N; Sundararajan, K; Vidya, K; Jemmis, Eluvathingal D

    2016-03-15

    Non-covalent halogen-bonding interactions between π cloud of acetylene (C2H2) and chlorine atom of carbon tetrachloride (CCl4) have been investigated using matrix isolation infrared spectroscopy and quantum chemical computations. The structure and the energies of the 1:1 C2H2-CCl4 adducts were computed at the B3LYP, MP2 and M05-2X levels of theory using 6-311++G(d,p) basis set. The computations indicated two minima for the 1:1 C2H2-CCl4 adducts; with the C-Cl…π adduct being the global minimum, where π cloud of C2H2 is the electron donor. The second minimum corresponded to a C-H…Cl adduct, in which C2H2 is the proton donor. The interaction energies for the adducts A and B were found to be nearly identical. Experimentally, both C-Cl…π and C-H…Cl adducts were generated in Ar and N2 matrixes and characterized using infrared spectroscopy. This is the first report on halogen bonded adduct, stabilized through C-Cl…π interaction being identified at low temperatures using matrix isolation infrared spectroscopy. Atoms in Molecules (AIM) and Natural Bond Orbital (NBO) analyses were performed to support the experimental results. The structures of 2:1 ((C2H2)2-CCl4) and 1:2 (C2H2-(CCl4)2) multimers and their identification in the low temperature matrixes were also discussed. PMID:26722673

  15. Non-covalent C-Cl…π interaction in acetylene-carbon tetrachloride adducts: Matrix isolation infrared and ab initio computational studies

    NASA Astrophysics Data System (ADS)

    Ramanathan, N.; Sundararajan, K.; Vidya, K.; Jemmis, Eluvathingal D.

    2016-03-01

    Non-covalent halogen-bonding interactions between π cloud of acetylene (C2H2) and chlorine atom of carbon tetrachloride (CCl4) have been investigated using matrix isolation infrared spectroscopy and quantum chemical computations. The structure and the energies of the 1:1 C2H2-CCl4 adducts were computed at the B3LYP, MP2 and M05-2X levels of theory using 6-311 ++G(d,p) basis set. The computations indicated two minima for the 1:1 C2H2-CCl4 adducts; with the C-Cl…π adduct being the global minimum, where π cloud of C2H2 is the electron donor. The second minimum corresponded to a C-H…Cl adduct, in which C2H2 is the proton donor. The interaction energies for the adducts A and B were found to be nearly identical. Experimentally, both C-Cl…π and C-H…Cl adducts were generated in Ar and N2 matrixes and characterized using infrared spectroscopy. This is the first report on halogen bonded adduct, stabilized through C-Cl…π interaction being identified at low temperatures using matrix isolation infrared spectroscopy. Atoms in Molecules (AIM) and Natural Bond Orbital (NBO) analyses were performed to support the experimental results. The structures of 2:1 ((C2H2)2-CCl4) and 1:2 (C2H2-(CCl4)2) multimers and their identification in the low temperature matrixes were also discussed.

  16. Evaluation of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Nontuberculous Mycobacteria from Clinical Isolates

    PubMed Central

    Ruiz-Serrano, María Jesús; Marín, Mercedes; López Roa, Paula; Rodríguez-Créixems, Marta; Bouza, Emilio

    2015-01-01

    Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) for the identification of nontuberculous mycobacterial (NTM) isolates was evaluated in this study. Overall, 125 NTM isolates were analyzed by MALDI-TOF and GenoType CM/AS. Identification by 16S rRNA/hsp65 sequencing was considered the gold standard. Agreements between MALDI-TOF and GenoType CM/AS with the reference method were, respectively, 94.4% and 84.0%. In 17 cases (13.6%), results provided by GenoType and MALDI-TOF were discordant; however, the reference method agreed with MALDI-TOF in 16/17 cases (94.1%; P = 0.002). PMID:26063855

  17. Casein kinase II protein kinase is bound to lamina-matrix and phosphorylates lamin-like protein in isolated pea nuclei

    NASA Technical Reports Server (NTRS)

    Li, H.; Roux, S. J.

    1992-01-01

    A casein kinase II (CK II)-like protein kinase was identified and partially isolated from a purified envelope-matrix fraction of pea (Pisum sativum L.) nuclei. When [gamma-32P]ATP was directly added to the envelope-matrix preparation, the three most heavily labeled protein bands had molecular masses near 71, 48, and 46 kDa. Protein kinases were removed from the preparation by sequential extraction with Triton X-100, EGTA, 0.3 M NaCl, and a pH 10.5 buffer, but an active kinase still remained bound to the remaining lamina-matrix fraction after these treatments. This kinase had properties resembling CK II kinases previously characterized from animal and plant sources: it preferred casein as an artificial substrate, could use GTP as efficiently as ATP as the phosphoryl donor, was stimulated by spermine, was calcium independent, and had a catalytic subunit of 36 kDa. Some animal and plant CK II kinases have regulatory subunits near 29 kDa, and a lamina-matrix-bound protein of this molecular mass was recognized on immunoblot by anti-Drosophila CK II polyclonal antibodies. Also found associated with the envelope-matrix fraction of pea nuclei were p34cdc2-like and Ca(2+)-dependent protein kinases, but their properties could not account for the protein kinase activity bound to the lamina. The 71-kDa substrate of the CK II-like kinase was lamin A-like, both in its molecular mass and in its cross-reactivity with anti-intermediate filament antibodies. Lamin phosphorylation is considered a crucial early step in the entry of cells into mitosis, so lamina-bound CK II kinases may be important control points for cellular proliferation.

  18. Matrix-assisted laser desorption/ionisation-time of flight mass spectrometry: rapid identification of bacteria isolated from patients with cystic fibrosis.

    PubMed

    Baillie, S; Ireland, K; Warwick, S; Wareham, D; Wilks, M

    2013-01-01

    Despite extensive research into the diagnosis and management of cystic fibrosis (CF) over the past decades, sufferers still have a median life expectancy of less than 37 years. Respiratory tract infections have a significant role in increasing the morbidity and mortality of patients with CF via a progressive decline in lung function. Rapid identification of organisms recovered from CF sputum is necessary for effective management of respiratory tract infections; however, standard techniques of identification are slow, technically demanding and expensive. The aim of this study is to asses the suitability of matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF MS) in identifying bacteria isolated from the respiratory tract of patients with CF, and is assessed by testing the accuracy of MALDI-TOF MS in identifying samples from a reference collection of rare CF strains in conjunction with comparing MALDI-TOF MS and standard techniques in identifying clinical isolates from sputum samples of CF patients. MALDI-TOF MS accurately identified 100% of isolates from the reference collection of rare CF pathogens (EuroCare CF collection). The isolate identification given by MALDI-TOF MS agreed with that given by standard techniques for 479/481 (99.6%) clinical isolates obtained from respiratory samples provided by patients with CE In two (0.4%) of 481 samples there was a discrepancy in identification between MALDI-TOF MS and standard techniques. One organism was identified as Pseudomonas aeruginosa by MALDI-TOF but could only be identified by the laboratory's standard methods as of the Pseudomonas genus. The second organism was identified as P. beteli by MALDI-TOF MS and Stenotrophomonas maltophilia by standard methods. This study shows that MALDI-TOF MS is superior to standard techniques in providing cheap, rapid and accurate identification of CF sputum isolates. PMID:24400425

  19. Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry for identification of Clostridium species isolated from Saudi Arabia.

    PubMed

    AlMogbel, Mohammed Suliman

    2016-01-01

    The aim of this study was to identify different Clostridium spp. isolated from currency notes from the Ha'il region of Saudi Arabia in September 2014 using MALDI-TOF-MS. Clostridium spp. were identified by Bruker MALDI-TOF-MS and compared with VITEK 2. The confirmation of the presence of different Clostridium spp. was performed by determining the sequence of the 16S ribosomal RNA gene. In this study, 144 Clostridium spp. were isolated. Among these specimens, MALDI-TOF-MS could identify 88.8% (128/144) of the isolates to the species level and 92.3% (133/144) to the genus level, whereas, VITEK 2 identified 77.7% of the (112/144) isolates. The correct identification of the 144 isolates was performed by sequence analysis of the 500bp 16S rRNA gene. The most common Clostridium spp. identified were Clostridium perfringens (67.36%), Clostridium subterminale (14.58%), Clostridium sordellii (9%) and Clostridium sporogenes (9%). The results of this study demonstrate that MALDI-TOF-MS is a rapid, accurate and user friendly technique for the identification of Clostridium spp. Additionally, MALDI-TOF-MS has advantages over VITEK 2 in the identification of fastidious micro-organisms, such as Clostridium spp. Incorporating this technique into routine microbiology would lead to more successful and rapid identification of pathogenic and difficult to identify micro-organisms. PMID:26991272

  20. Photochemical and thermal isomerizations of C 2h and C 2v forms of para-benzoquinone dioxime: A matrix-isolation study

    NASA Astrophysics Data System (ADS)

    Lapinski, Leszek; Stepanenko, Tetyana; Rode, Michal F.; Nowak, Maciej J.

    2010-07-01

    The C 2h and C 2v isomers of para-benzoquinone dioxime were studied using matrix isolation technique combined with infrared spectroscopy. The energies of these two forms were theoretically estimated (at the MP2 and CASSCF) to be nearly equal, with the C 2h isomer slightly more stable (by 1-2 kJ mol -1). Both C 2h and C 2v forms were observed in low-temperature Ar matrices. It was experimentally found that the population ratio of the two isomers depends on the conditions of preparation of the solid para-benzoquinone dioxime sample used for deposition of the matrix. UV irradiation of the matrix-isolated para-benzoquinone dioxime led to a photochemical transformation of the C 2v isomer into the C 2h form. These findings allowed separation of the infrared spectra of the two isomers. The assignment of the C 2v structure to the substrate of the phototransformation as well as identification of the C 2h photoproduct structure was achieved by comparison of the experimental IR spectra with the spectra theoretically predicted at the DFT(B3LYP)/6-31++G(d,p) level. Complementarily to the experimental observation of the C 2v → C 2h photoisomerization, the methods of computational photochemistry were employed to calculate potential energy surfaces of the ground (S 0) and the first excited singlet (S 1) electronic states of para-benzoquinone. These calculations, carried out at the CASSCF level, resulted in localization of a conical intersection between the S 0 and S 1 states. At the optimized geometry of the conical intersection point, one of the hydroxylimino groups was found to adopt a perpendicular orientation with respect to the six-membered ring, whereas the other hydroxylimino group remained coplanar with the ring.

  1. HOSO/sub 2/ and HOSO/sub 4/ radicals studied by ab initio calculation and matrix isolation technique

    SciTech Connect

    Nagase, S.; Hashimoto, S.; Akimoto, H.

    1988-02-11

    Sulfo (HOSO/sub 2/) and sulfodioxy (HOSO/sub 4/) radicals have been characterized by use of ab initio calculations at the HF/3-21G(*) level, and the results were compared with the infrared spectral data from low-temperature-matrix experiments. The calculated vibrational frequencies and the isotope shift as well as a supplemental experimental result supported the assignment of the observed infrared absorption bands in the Ar matrix at 3539.9 (3528.6), 1309.2 (1308.7), 1097.3 (1096.0), and 759.5 (735.1) cm/sup -1/ to the O--H st, S(=O)/sub 2/ asym st, S(=O)/sub 2/ sym st, and S-OH st modes of the H/sup 16/OS/sup 16/O/sub 2/ (H/sup 18/OS/sup 16/O/sub 2/) radical, respectively. The HOSO/sub 4/ radical was found to be located as a minimum on the potential surface, and the fully optimized geometry and vibrational frequencies were obtained, although the detection of the radical in the O/sub 2/ matrix was unsuccessful. Enthalpy changes for the reactions HOSO/sub 2/ + O/sub 2/ ..-->.. HO/sub 2/ + SO/sub 3/ (2) and HOSO/sub 2/ + O/sub 2/ ..-->.. HOSO/sub 4/ (3) were calculated at the MP4(SDTQ)/6031G**//3-21G(*) and MP3/6-31G**//3-21G(*) levels, respectively, and the results were discussed in comparison with the experimental evidence

  2. Fourier transform infrared (FTIR) spectroscopy.

    PubMed

    Berthomieu, Catherine; Hienerwadel, Rainer

    2009-01-01

    Fourier transform infrared (FTIR) spectroscopy probes the vibrational properties of amino acids and cofactors, which are sensitive to minute structural changes. The lack of specificity of this technique, on the one hand, permits us to probe directly the vibrational properties of almost all the cofactors, amino acid side chains, and of water molecules. On the other hand, we can use reaction-induced FTIR difference spectroscopy to select vibrations corresponding to single chemical groups involved in a specific reaction. Various strategies are used to identify the IR signatures of each residue of interest in the resulting reaction-induced FTIR difference spectra. (Specific) Isotope labeling, site-directed mutagenesis, hydrogen/deuterium exchange are often used to identify the chemical groups. Studies on model compounds and the increasing use of theoretical chemistry for normal modes calculations allow us to interpret the IR frequencies in terms of specific structural characteristics of the chemical group or molecule of interest. This review presents basics of FTIR spectroscopy technique and provides specific important structural and functional information obtained from the analysis of the data from the photosystems, using this method. PMID:19513810

  3. Morphology and structure features of ZnAl{sub 2}O{sub 4} spinel nanoparticles prepared by matrix-isolation-assisted calcination

    SciTech Connect

    Du, Xuelian; Li, Liqiang; Zhang, Wenxing; Chen, Wencong; Cui, Yuting

    2015-01-15

    Graphical abstract: The substrate ZnO as the isolation medium is effective in preventing the sintering and agglomeration of ZnAl{sub 2}O{sub 4} nanoparticles, and it also prevents their contamination. High purity, well-dispersed, and single-crystal ZnAl{sub 2}O{sub 4} nanoparticles with 3.72 eV band gap were obtained. - Abstract: Well-dispersed ZnAl{sub 2}O{sub 4} spinel nanoparticles with an average crystalline size of 25.7 nm were synthesized successfully and easily by polymer-network and matrix-isolation-assisted calcination. The product microstructure and features were investigated by X-ray diffractometry, thermogravimetric and differential thermal analysis, Fourier transform-infrared spectroscopy, N{sub 2} adsorption–desorption isotherms, and energy dispersive X-ray spectra. The morphology and optical performance of the as-prepared ZnAl{sub 2}O{sub 4} nanoparticles were characterized by scanning electron microscope, transmission electron microscopy, and photoluminescence spectrometer. Experimental results indicate that excess ZnO acted as the isolation medium is effective in preventing the sintering and agglomeration of ZnAl{sub 2}O{sub 4} nanoparticles, and it also prevents their contamination. Then, high purity and well-dispersed ZnAl{sub 2}O{sub 4} nanoparticles with single-crystal structure were obtained.

  4. Photoacoustic FTIR spectroscopic study of undisturbed human cortical bone

    NASA Astrophysics Data System (ADS)

    Gu, Chunju; Katti, Dinesh R.; Katti, Kalpana S.

    2013-02-01

    Chemical pretreatment has been the prevailing sample preparation procedure for infrared (IR) spectroscopic studies on bone. However, experiments have indicated that chemical pretreatment can potentially affect the interactions between the components. Typically the IR techniques have involved transmission experiments. Here we report experimental studies using photoacoustic Fourier transform infrared spectroscopy (PA-FTIR). As a nondestructive technique, PA-FTIR can detect absorbance spectrum from a sample at controllable sampling depth and with little or no sample preparation. Additionally, the coupling inert gas, helium, which is utilized in the PA-FTIR system, can inhibit bacteria growth of bone by displacing oxygen. Therefore, we used this technique to study the undisturbed human cortical bone. It is found that photoacoustic mode (linear-scan, LS-PA-FTIR) can obtain basically similar spectra of bone as compared to the traditional transmission mode, but it seems more sensitive to amide III and ν2 carbonate bands. The ν3 phosphate band is indicative of detailed mineral structure and symmetry of native bone. The PA-FTIR depth profiling experiments on human cortical bone also indicate the influence of water on OH band and the cutting effects on amide I and mineral bands. Our results indicate that phosphate ion geometry appears less symmetric in its undisturbed state as detected by the PA-FTIR as compared to higher symmetry observed using transmission techniques on disturbed samples. Moreover, the PA-FTIR spectra indicate a band at 1747 cm-1 possibly resulting from Cdbnd O stretching of lipids, cholesterol esters, and triglycerides from the arteries. Comparison of the spectra in transverse and longitudinal cross-sections demonstrates that, the surface area of the longitudinal section bone appears to have more organic matrix exposed and with higher mineral stoichiometry.

  5. Matrix-isolation and computational study of the HXeY⋯H2O complexes (Y = Cl, Br, and I).

    PubMed

    Tsuge, Masashi; Berski, Sławomir; Räsänen, Markku; Latajka, Zdzisław; Khriachtchev, Leonid

    2014-01-28

    The HXeY⋯H2O complexes (Y = Cl, Br, and I) are studied theoretically and experimentally. The calculations at the CCSD(T)/def2-TZVPPD level of theory predict two stable structures for Y = Cl and Br and one structure for Y = I, with interaction energies up to about -7 kcal mol(-1). In the experiments, we have identified several infrared absorption bands originating from the H-Xe stretching mode of these complexes in a xenon matrix. The monomer-to-complex frequency shifts of this mode are up to +82 cm(-1) (Y = Cl), +101 cm(-1) (Y = Br), and +138 cm(-1) (Y = I), i.e., the shift is smaller for more strongly bound molecules. Based on the agreement of the experimental and theoretical results, the observed bands are assigned to the most stable planar structure with an O-H⋯Y-Xe hydrogen bond. PMID:25669539

  6. The influence of landscape matrix on isolated patch use by wide-ranging animals: conservation lessons for woodland caribou.

    PubMed

    Lesmerises, Rémi; Ouellet, Jean-Pierre; Dussault, Claude; St-Laurent, Martin-Hugues

    2013-09-01

    For conservation purposes, it is important to design studies that explicitly quantify responses of focal species to different land management scenarios. Here, we propose an approach that combines the influence of landscape matrices with the intrinsic attributes of remaining habitat patches on the space use behavior of woodland caribou (Rangifer tarandus caribou), a threatened subspecies of Rangifer. We sought to link characteristics of forest remnants and their surrounding environment to caribou use (i.e., occurrence and intensity). We tracked 51 females using GPS telemetry north of the Saguenay River (Québec, Canada) between 2004 and 2010 and documented their use of mature forest remnants ranging between 30 and ∼170 000 ha in a highly managed landscape. Habitat proportion and anthropogenic feature density within incremental buffer zones (from 100 to 7500 m), together with intrinsic residual forest patch characteristics, were linked to caribou GPS location occurrence and density to establish the range of influence of the surrounding matrix. We found that patch size and composition influence caribou occurrence and intensity of use within a patch. Patch size had to reach approximately 270 km(2) to attain 75% probability of use by caribou. We found that small patches (<100 km(2)) induced concentration of caribou activities that were shown to make them more vulnerable to predation and to act as ecological traps. Woodland caribou clearly need large residual forest patches, embedded in a relatively undisturbed matrix, to achieve low densities as an antipredator strategy. Our patch-based methodological approach, using GPS telemetry data, offers a new perspective of space use behavior of wide-ranging species inhabiting fragmented landscapes and allows us to highlight the impacts of large scale management. Furthermore, our study provides insights that might have important implications for effective caribou conservation and forest management. PMID:24101980

  7. Matrix isolation model studies on the radiation-induced transformations of small molecules of astrochemical and atmospheric interest

    NASA Astrophysics Data System (ADS)

    Feldman, Vladimir I.; Ryazantsev, Sergey V.; Saenko, Elizaveta V.; Kameneva, Svetlana V.; Shiryaeva, Ekaterina S.

    2016-07-01

    The radiation-induced transformations of small molecules at low temperatures play an important role in the interstellar, planetary and atmospheric chemistry. This work presents a review of our recent model studies on the radiation chemistry of relevant molecules in solid noble gas (Ng) matrices, including some preliminary new results. Among the triatomic molecules, water and carbon dioxide were studied in detail. The radiation-induced degradation of isolated H2O yields hydrogen atoms and OH radicals, while oxygen atoms are produced at higher doses. Isolated CO2 molecules are decomposed to yield CO and trapped oxygen atoms. Upon annealing the trapped O and H atoms are mobilized selectively at different temperatures and react with other trapped species. The formation of HCO and HOCO radicals was observed in the mixed H2O/CO2/Ng systems. Other studies were concerned with the radiation-induced degradation of simple organic molecules (methanol, formic acid) and chlorofluorocarbons (CFCl3, CF2Cl2). Preliminary results for methanol revealed deep dehydrogenation yielding HCO and CO, whereas CO2, CO and HOCO were detected as primary products for formic acid. In the case of chlorofluorocarbons, significance of ionic channels was demonstrated. The implications of the results for modeling the processes in astrochemical ices and atmosphere are discussed.

  8. Matrix Isolation IR Spectroscopy and Quantum Chemistry Study of 1:1 Π-HYDROGEN Bonded Complexes of Benzene with a Series of Fluorophenols

    NASA Astrophysics Data System (ADS)

    Banerjee, Pujarini; Chakraborty, Tapas

    2015-06-01

    O-H stretching infrared fundamentals (νb{OH}) of phenol and a series of fluorophenol monomers and their 1:1 complexes with benzene have been measured under a matrix isolation condition (8K). For the phenol-benzene complex the measured shift of νb{OH} is 78 wn and for 3, 4, 5-trifluorophenol it is 98 wn. Although the cold matrix isolation environment is very different from an aqueous medium, the measured spectral shifts display an interesting linear correlation with the aqueous phase acid dissociation constants (pKa) of the phenols. The spectral shifts predicted by quantum chemistry calculations at several levels of theory are consistent with the observed values. Correlations of the shifts are also found with respect to energetic, geometric and several other electronic structure parameters of the complexes. Partitioning of binding energies of the complexes into components following the Morokuma-Kitaura scheme shows that dispersion is the predominant component of attractive interaction, and electrostatics, polarization and charge-transfer terms also have contributions to overall binding stability. NBO analysis reveals that hyperconjugative charge-transfers from the filled π-orbitals of the hydrogen bond acceptor (benzene) to the anti-bonding σ*(O-H) orbital of the donors (phenols) display correlations which are fully consistent with the observed variations of spectral shifts. The analysis also shows that the O-H bond dipole moments of all the phenolic species are nearly the same, implying that local electrostatics has only a little effect at the site of hydrogen bonding.

  9. Experimental evidence for blue-shifted hydrogen bonding in the fluoroform-hydrogen chloride complex: a matrix-isolation infrared and ab initio study.

    PubMed

    Gopi, R; Ramanathan, N; Sundararajan, K

    2014-07-24

    The 1:1 hydrogen-bonded complex of fluoroform and hydrogen chloride was studied using matrix-isolation infrared spectroscopy and ab initio computations. Using B3LYP and MP2 levels of theory with 6-311++G(d,p) and aug-cc-pVDZ basis sets, the structures of the complexes and their energies were computed. For the 1:1 CHF3-HCl complexes, ab initio computations showed two minima, one cyclic and the other acyclic. The cyclic complex was found to have C-H · · · Cl and C-F · · · H interactions, where CHF3 and HCl sub-molecules act as proton donor and proton acceptor, respectively. The second minimum corresponded to an acyclic complex stabilized only by the C-F · · · H interaction, in which CHF3 is the proton acceptor. Experimentally, we could trap the 1:1 CHF3-HCl cyclic complex in an argon matrix, where a blue-shift in the C-H stretching mode of the CHF3 sub-molecule was observed. To understand the nature of the interactions, Atoms in Molecules and Natural Bond Orbital analyses were carried out to unravel the reasons for blue-shifting of the C-H stretching frequency in these complexes. PMID:24979667

  10. Infrared spectra and ultraviolet-tunable laser induced photochemistry of matrix-isolated phenol and phenol-d5

    NASA Astrophysics Data System (ADS)

    Giuliano, Barbara Michela; Reva, Igor; Lapinski, Leszek; Fausto, Rui

    2012-01-01

    Monomers of phenol and its ring-perdeuterated isotopologue phenol-d5 were isolated in argon matrices at 15 K. The infrared (IR) spectra of these species were recorded and analyzed. In situ photochemical transformations of phenol and phenol-d5 were induced by tunable UV laser light. The photoproducts have been characterized by IR spectroscopy supported by theoretical calculations of the infrared spectra. The primary product photogenerated from phenol was shown to be the phenoxyl radical. The analysis of the progress of the observed phototransformations led to identification of 2,5-cyclohexadienone as one of the secondary photoproducts. Spectral indications of other secondary products, such as the Dewar isomer and the open-ring ketene, were also detected. Identification of the photoproducts provided a guide for the interpretation of the mechanisms of the observed photoreactions.

  11. Infrared spectra and ultraviolet-tunable laser induced photochemistry of matrix-isolated phenol and phenol-d{sub 5}

    SciTech Connect

    Giuliano, Barbara Michela; Reva, Igor; Fausto, Rui; Lapinski, Leszek

    2012-01-14

    Monomers of phenol and its ring-perdeuterated isotopologue phenol-d{sub 5} were isolated in argon matrices at 15 K. The infrared (IR) spectra of these species were recorded and analyzed. In situ photochemical transformations of phenol and phenol-d{sub 5} were induced by tunable UV laser light. The photoproducts have been characterized by IR spectroscopy supported by theoretical calculations of the infrared spectra. The primary product photogenerated from phenol was shown to be the phenoxyl radical. The analysis of the progress of the observed phototransformations led to identification of 2,5-cyclohexadienone as one of the secondary photoproducts. Spectral indications of other secondary products, such as the Dewar isomer and the open-ring ketene, were also detected. Identification of the photoproducts provided a guide for the interpretation of the mechanisms of the observed photoreactions.

  12. [Isolation and in vitro translation of polysomes and the RNA matrix from gibberellic acid-treated etiolated dwarf pea shoots].

    PubMed

    Kilev, S N; Evtushenko, E V; Chekurov, V M; Mertvetsov, N P

    1983-08-01

    The effect of gibberellic acid (GA) on the size of polysomes (PS) and on the specific translation activity of epicotyl PS of two dwarf pea varieties was studied. It was shown that GA does not significantly alter the specific translation activity of PS and of mRNA isolated from dwarf pea epicotyl PS. Electrophoretic separation of the polypeptides synthesized in a cell-free protein-synthesizing system in PS of control and GA-treated shoots revealed no differences between them. Some minor qualitative and quantitative differences in the protein composition of the cytoplasm of control and hormone-treated shoots were found. Possible influence of GA on the composition of a definite class of mRNA and on posttranslational processing of plant proteins is discussed. PMID:6194827

  13. Fast characterization of industrial soy protein isolates by direct analysis with matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

    PubMed

    Horneffer, Verena; Foster, Tim J; Velikov, Krassimir P

    2007-12-26

    Industrial soy protein isolates (SPIs) due to differences in their processing conditions may differ both in composition and in degree of hydrolysis. As a result, they display different performance in food production and final food properties like consistency and taste. To address this issue, a fast, cheap, and simple method for screening and characterization is required. In this article, the successful analysis of soy protein isolates, a complex mixture of proteins with glycinin and beta-conglycinin as major components, by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is demonstrated. The preparation implements a fast extraction of the proteins from the raw SPI either under neutral or reducing conditions. The extracts are analyzed subsequently by MALDI-TOF-MS without further purification. Results of the two conditions are compared. Finally, different SPIs from different suppliers are analyzed and compared concerning their consistency. The method could be applied to other plant proteins and mixtures thereof. Since the composition and intactness of different subunits play important roles in functional properties of soy proteins, rapid methods for fingerprinting of different industrial soy protein sources will be valuable tools for successful product formulation. PMID:18052236

  14. Photoactivation of the Ni-SIr state to the Ni-SIa state in [NiFe] hydrogenase: FT-IR study on the light reactivity of the ready Ni-SIr state and as-isolated enzyme revisited.

    PubMed

    Tai, Hulin; Xu, Liyang; Inoue, Seiya; Nishikawa, Koji; Higuchi, Yoshiki; Hirota, Shun

    2016-08-10

    The Ni-SIr state of [NiFe] hydrogenase from Desulfovibrio vulgaris Miyazaki F was photoactivated to its Ni-SIa state by Ar(+) laser irradiation at 514.5 nm, whereas the Ni-SL state was light induced from a newly identified state, which was less active than any other identified state and existed in the "as-isolated" enzyme. PMID:27456760

  15. Human mesenchymal stem cells from the umbilical cord matrix: successful isolation and ex vivo expansion using serum-/xeno-free culture media.

    PubMed

    Simões, Irina N; Boura, Joana S; dos Santos, Francisco; Andrade, Pedro Z; Cardoso, Carla M P; Gimble, Jeffrey M; da Silva, Cláudia L; Cabral, Joaquim M S

    2013-04-01

    Mesenchymal stem cells (MSC) could potentially be applied in therapeutic settings due to their multilineage differentiation ability, immunomodulatory properties, as well as their trophic activity. The umbilical cord matrix (UCM) represents a promising source of MSC for biomedical applications. The number of cells isloated per umbilical cord (UC) unit is limited and ex vivo expansion is imperative in order to reach clinically meaningful cell numbers. The limitations of poorly defined reagents (e.g. fetal bovine serum, which is commonly used as a supplement for human MSC expansion) make the use of serum-/xeno-free conditions mandatory. We demonstrated the feasibility of isolating UCM-MSC by plastic adherence using serum-/xeno-free culture medium following enzymatic digestion of UCs, with a 100% success rate. 2.6 ± 0.21 × 10(5) cells were isolated per UC unit, of which 1.9 ± 0.21 × 10(5) were MSC-like cells expressing CD73, CD90, and CD105. When compared to adult sources (bone marrow-derived MSC and adipose-derived stem/stromal cells), UCM-MSC displayed a similar immunophenotype and similar multilineage differentiation ability, while demonstrating a higher expansion potential (average fold increase of 7.4 for serum-containing culture medium and 11.0 for xeno-free culture medium (P3-P6)). The isolation and expansion of UCM-MSC under defined serum-/xeno-free conditions contributes to safer and more effective MSC cellular products, boosting the usefulness of MSC in cellular therapy and tissue engineering. PMID:23420807

  16. Identification of Haemophilus influenzae Type b Isolates by Use of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry.

    PubMed

    Månsson, Viktor; Resman, Fredrik; Kostrzewa, Markus; Nilson, Bo; Riesbeck, Kristian

    2015-07-01

    Haemophilus influenzae type b (Hib) is, in contrast to non-type b H. influenzae, associated with severe invasive disease, such as meningitis and epiglottitis, in small children. To date, accurate H. influenzae capsule typing requires PCR, a time-consuming and cumbersome method. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) provides rapid bacterial diagnostics and is increasingly used in clinical microbiology laboratories. Here, MALDI-TOF MS was evaluated as a novel approach to separate Hib from other H. influenzae. PCR-verified Hib and non-Hib reference isolates were selected based on genetic and spectral characteristics. Mass spectra of reference isolates were acquired and used to generate different classification algorithms for Hib/non-Hib differentiation using both ClinProTools and the MALDI Biotyper software. A test series of mass spectra from 33 Hib and 77 non-Hib isolates, all characterized by PCR, was used to evaluate the algorithms. Several algorithms yielded good results, but the two best were a ClinProTools model based on 22 separating peaks and subtyping main spectra (MSPs) using MALDI Biotyper. The ClinProTools model had a sensitivity of 100% and a specificity of 99%, and the results were 98% reproducible using a different MALDI-TOF MS instrument. The Biotyper subtyping MSPs had a sensitivity of 97%, a specificity of 100%, and 93% reproducibility. Our results suggest that it is possible to use MALDI-TOF MS to differentiate Hib from other H. influenzae. This is a promising method for rapidly identifying Hib in unvaccinated populations and for the screening and surveillance of Hib carriage in vaccinated populations. PMID:25926500

  17. The optical spectra of matrix-isolated palladium-nitrogen complexes: An investigation by absorption, emission, and photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Schrittenlacher, W.; Schroeder, W.; Rotermund, H. H.; Wiggenhauser, H.; Grinter, R.; Kolb, D. M.

    1986-08-01

    The optical spectra of palladium in neon and argon matrices containing up to 100% dinitrogen have been studied. Beside the known bands of isolated Pd atoms new strong bands assigned to weakly bonded Pd(N2)m (m=1, 2) complexes appear. The bands are attributed to three different types of transition. The dominant lines are essentially due to transitions localized at the Pd atom but strongly perturbed by a ``crystal field'' due to the weakly bonded N2 molecules. Secondly, a vibrational progression at lower energies is assigned to a Pd to N2 charge transfer transition and thirdly, at high energies, a vibrational progression assigned to a locally excited state of an N2 molecule perturbed by weak bonding to Pd is observed. No evidence has been found for the presence of Pd(N2)3. Photoelectron spectra of the Pd(N2)m complexes in neon have been observed. The Pd 4d photoemission peak is shifted with respect to the Pd atom in Ne by ˜1.1 eV to higher binding energies.

  18. Chemical characterization of torbanites by transmission micro-FTIR spectroscopy: Origin and extent of compositional heterogeneities

    NASA Astrophysics Data System (ADS)

    Landais, Patrick; Rochdi, Aïcha; Largeau, Claude; Derenne, Sylvie

    1993-06-01

    Four Permian to Carboniferous torbanites of various geographical origins were examined by transmission micro-FTIR spectroscopy on doubly polished thin sections (10-25 μm). Several types of heterogeneities (different types of organic matrix; yellow and orange Botryococcus braunii colonies) were identified and chemically characterized. Important differences were noted between the organic constituents of the matrix and the algal bodies, regarding the intensity of OH, CO, and aromatic CC absorptions. The previous IR studies of torbanites on bulk samples therefore afforded substantially biased information on the composition of B. braunii fossil colonies, on their oil potential, and on the maturity of such kerogens. Micro-FTIR spectra indicate that the organic matrix corresponds neither to an extensive breaking up of colonies nor to humic substances. This matrix is highly heterogeneous; two types were identified in the Autun sample (chiefly corresponding to degraded algal and bacterial constituents, respectively). A precise characterization of the organic matrix was made difficult, however, in Pumpherston torbanite, due to intimate mixing with minerals. The co-occurrence of yellow and orange colonies, with contrasted micro-FTIR features, in Autun torbanite neither reflects radiolysis processes nor differences in maturation and/or source algae. A specific spatial relation was observed between these two types of algal bodies and the organo-mineral matrix, thus revealing differences in colony microenvironment after deposition. The orange colonies are likely derived, in agreement with their micro-FTIR spectra and their spatial correlation with the matrix, from sedimentological and/or matrix-catalysed diagenetic transformations of some yellow colonies. This first application of micro-FTIR to kerogens confirmed the utility of this nondestructive, in situ pin-point method. Although torbanites have been extensively studied, all the analytical methods so far used only

  19. Conformers, infrared spectrum, UV-induced photochemistry, and near-IR-induced generation of two rare conformers of matrix-isolated phenylglycine

    SciTech Connect

    Borba, Ana Fausto, Rui; Gómez-Zavaglia, Andrea

    2014-10-21

    The conformational space of α-phenylglycine (PG) have been investigated theoretically at both the DFT/B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) levels of approximation. Seventeen different minima were found on the investigated potential energy surfaces, which are characterized by different dominant intramolecular interactions: type I conformers are stabilized by hydrogen bonds of the type N–H···O=C, type II by a strong O–H···N hydrogen bond, type III by weak N–H···O–H hydrogen bonds, and type IV by a C=O···H–C contact. The calculations indicate also that entropic effects are relevant in determining the equilibrium populations of the conformers of PG in the gas phase, in particular in the case of conformers of type II, where the strong intramolecular O–H···N hydrogen bond considerably diminishes entropy by reducing the conformational mobility of the molecule. In consonance with the relative energies of the conformers and barriers for conformational interconversion, only 3 conformers of PG were observed for the compound isolated in cryogenic Ar, Xe, and N{sub 2} matrices: the conformational ground state (ICa), and forms ICc and IITa. All other significantly populated conformers existing in the gas phase prior to deposition convert either to conformer ICa or to conformer ICc during matrix deposition. The experimental observation of ICc had never been achieved hitherto. Narrowband near-IR irradiation of the first overtone of νOH vibrational mode of ICa and ICc in nitrogen matrices (at 6910 and 6930 cm{sup −1}, respectively) led to selective generation of two additional conformers of high-energy, ITc and ITa, respectively, which were also observed experimentally for the first time. In addition, these experiments also provided the key information for the detailed vibrational characterization of the 3 conformers initially present in the matrices. On the other hand, UV irradiation (λ = 255 nm) of PG isolated in a xenon matrix revealed that

  20. Matrix-isolation studies on the radiation-induced chemistry in H₂O/CO₂ systems: reactions of oxygen atoms and formation of HOCO radical.

    PubMed

    Ryazantsev, Sergey V; Feldman, Vladimir I

    2015-03-19

    The radiation-induced transformations occurring upon X-ray irradiation of solid CO2/H2O/Ng systems (Ng = Ar, Kr, Xe) at 8-10 K and subsequent annealing up to 45 K were studied by Fourier transform infrared spectroscopy. The infrared (IR) spectra of deposited matrices revealed the presence of isolated monomers, dimers, and intermolecular H2O···CO2 complexes. Irradiation resulted in effective decomposition of matrix-isolated carbon dioxide and water yielding CO molecules and OH radicals, respectively. Annealing of the irradiated samples led to formation of O3, HO2, and a number of xenon hydrides of HXeY type (in the case of xenon matrices). The formation of these species was used for monitoring of the postirradiation thermally induced chemical reactions involving O and H atoms generated by radiolysis. It was shown that the radiolysis of CO2 in noble-gas matrices produced high yields of stabilized oxygen atoms. In all cases, the temperatures at which O atoms become mobile and react are lower than those of H atoms. Dynamics and reactivity of oxygen atoms was found to be independent of the precursor nature. In addition, the formation of HOCO radicals was observed in all the noble-gas matrices at remarkably low temperatures. The IR spectra of HOCO and DOCO were first characterized in krypton and xenon matrices. It was concluded that the formation of HOCO was mainly due to the radiation-induced evolution of the weakly bound H2O···CO2 complexes. This result indicates the significance of weak intermolecular interactions in the radiation-induced chemical processes in inert low-temperature media. PMID:25469518

  1. Spectroscopic and computational studies of matrix-isolated iso-CHBr{sub 3}: Structure, properties, and photochemistry of iso-bromoform

    SciTech Connect

    George, Lisa; Kalume, Aimable; Wagner, James; Reid, Scott A.; Esselman, Brian J.; McMahon, Robert J.

    2011-09-28

    Iso-polyhalomethanes are known reactive intermediates that play a pivotal role in the photochemistry of halomethanes in condensed phases. In this work, iso-bromoform (iso-CHBr{sub 3}) and its deuterated isotopomer were characterized by matrix isolation infrared and UV/visible spectroscopy, supported by ab initio and density functional theory calculations, to further probe the structure, spectroscopy, and photochemistry of this important intermediate. Selected wavelength laser irradiation of CHBr{sub 3} isolated in Ar or Ne matrices at {approx}5 K yielded iso-CHBr{sub 3}; the observed infrared and UV/visible absorptions are in excellent agreement with computational predictions, and the energies of various stationary points on the CHBr{sub 3} potential energy surface were characterized computationally using high-level methods in combination with correlation consistent basis sets. These calculations show that, while the corresponding minima lie {approx}200 kJ/mol above the global CHBr{sub 3} minimum, the isomer is bound by some 60 kJ/mol in the gas phase with respect to the CHBr{sub 2}+ Br asymptote. The photochemistry of iso-CHBr{sub 3} was investigated by selected wavelength laser irradiation into the intense S{sub 0}{yields} S{sub 3} transition, which resulted in back photoisomerization to CHBr{sub 3}. Intrinsic reaction coordinate calculations confirmed the existence of a first-order saddle point connecting the two isomers, which lies energetically below the threshold of the radical channel. Subsequently, natural bond orbital analysis and natural resonance theory were used to characterize the important resonance structures of the isomer and related stationary points, which demonstrate that the isomerization transition state represents a crossover from dominantly covalent to dominantly ionic bonding. In condensed phases, the ion-pair dominated isomerization transition state structure is preferentially stabilized, so that the barrier to isomerization is lowered.

  2. Microarray Identifies Extensive Downregulation of Noncollagen Extracellular Matrix and Profibrotic Growth Factor Genes in Chronic Isolated Mitral Regurgitation in the Dog

    PubMed Central

    Zheng, Junying; Chen, Yuanwen; Pat, Betty; Dell’Italia, Louis A; Tillson, Michael; Dillon, A Ray; Powell, Pamela; Shi, Ke; Shah, Neil; Denney, Thomas; Husain, Ahsan; Dell’Italia, Louis J

    2011-01-01

    Background The volume overload of isolated mitral regurgitation (MR) in the dog results in left ventricular (LV) dilatation and interstitial collagen loss. To better understand the mechanism of collagen loss we performed a gene array and overlaid regulated genes into Ingenuity Pathway Analysis (IPA). Methods and Results Gene arrays from LV tissue were compared in 4 dogs prior to and 4 months after MR. Cine-magnetic resonance-derived LV end-diastolic volume increased 2-fold (p=0.005) and LV ejection fraction increased from 41 to 53% (p < 0.001). LV interstitial collagen decreased 40% (p<0.05) compared to controls and replacement collagen was in short strands and in disarray. IPA identified Marfan’s syndrome, aneurysm formation, LV dilatation, and myocardial infarction, all of which have extracellular matrix (ECM) protein defects and/or degradation. MMP-1 and -9 mRNA increased 5- (p=0.01) and 10-fold (0.003), while collagen I did not change and collagen III mRNA increased 1.5-fold (p=0.02). However, noncollagen genes important in ECM structure were significantly downregulated, including decorin, fibulin 1, and fibrillin 1. Decorin mRNA downregulation correlated with LV dilatation (r= 0.83 p<0.05). In addition, connective tissue growth factor and plasminogen activator inhibitor were downregulated, along with multiple genes in TGF-β signaling pathway, resulting decreased LV TGF-β1 activity (p=0.03). Conclusions LV collagen loss in isolated, compensated MR is chiefly due to post-translational processing and degradation. The downregulation of multiple noncollagen genes important in global ECM structure, coupled with decreased expression of multiple profibrotic factors, explain the failure to replace interstitial collagen in the MR heart. PMID:19349319

  3. Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Compounds and Their Ions. 7; Phenazine, a Dual Substituted Polycyclic Aromatic Nitrogen Heterocycle

    NASA Technical Reports Server (NTRS)

    Mattioda, A. L.; Hudgins, D. M.; Bauschlicher, C. W., Jr.; Allamandola, L. J.

    2004-01-01

    The matrix-isolation technique has been employed to measure the mid-infrared spectra of phenazine (C12H8N2), a dual substituted Polycyclic Aromatic Nitrogen Heterocycle (PANH), in the neutral, cationic and anionic forms. The experimentally measured band frequencies and intensities are tabulated and compared with their calculated values as well as those of the non-substituted parent molecule, anthracene. The theoretical band positions and intensities were calculated using both the 3-31 G as well as the larger 6-3lG* Basis Sets. A comparison of the results can be found in the tables. The spectroscopic properties of phenazine and its cation are similar to those observed in mono-substituted PANHs, with one exception. The presence of a second nitrogen atom results in an additional enhancement of the cation's total integrated intensity, for the 1500-1000 cm(sup -1) (6.7 to 10 micron) region, over that observed for a mono-substituted PANH cation. The significance of this enhancement and the astrobiological implications of these results are discussed.

  4. The Identification of Complex Organic Molecules in the Interstellar Medium: Using Lasers and Matrix Isolation Spectroscopy to Simulate the Interstellar Environment

    NASA Technical Reports Server (NTRS)

    Stone, Bradley M.

    1998-01-01

    The Astrochemistry Group at NASA Ames Research Center is interested in the identification of large organic molecules in the interstellar medium Many smaller organic species (e.g. hydrocarbons, alcohols, etc.) have been previously identified by their radiofrequency signature due to molecular rotations. However, this becomes increasingly difficult to observe as the size of the molecule increases. Our group in interested in the identification of the carriers of the Diffuse Interstellar Bands (absorption features observed throughout the visible and near-infrared in the spectra of stars, due to species in the interstellar medium). Polycyclic Aromatic Hydrocarbons (PAHs) and related molecules are thought to be good candidates for these carriers. Laboratory experiments am performed at Ames to simulate the interstellar environment, and to compare spectra obtained from molecules in the laboratory to those derived astronomically. We are also interested in PAHs with respect to their possible connection to the UIR (Unidentified infrared) and ERE (Extended Red Emission) bands - emission features found to emanate from particular regions of our galaxy (e.g. Orion nebula, Red Rectangle, etc.). An old, "tried and proven spectroscopic technique, matrix isolation spectroscopy creates molecular conditions ideal for performing laboratory astrophysics.

  5. Donor-Acceptor Complexes between Ammonia and Sulfur Trioxide: An FTIR and Computational Study.

    PubMed

    Haupa, Karolina; Bil, Andrzej; Mielke, Zofia

    2015-10-29

    The complexes of ammonia with sulfur trioxide have been studied using FTIR matrix isolation spectroscopy and DFT/B3LYP calculations with the aug-cc-pVTZ basis set. The NH3/SO3/Ar matrixes were prepared in two different ways. In one set of experiments the matrix was prepared by the simultaneous deposition of the NH3/Ar mixture and SO3 vapor from the thermal decomposition of K2S2O7. In the second set of experiments thermolysis products of sulfamic acid were trapped in an argon matrix. Both methods of matrix preparation led to the formation of the H3N·SO3 electron donor-acceptor complex that was characterized earlier. In the matrixes comprising thermolysis products of sulfamic acid, in addition to H3N·SO3, the H3N-SO3···NH3 complex (II(D)) was also identified. The identity of the complex was confirmed by comparison of the experimental and theoretical spectra of H3N-SO3···NH3 and D3N-SO3···ND3. The performed calculations show that in H3N-SO3···NH3 the two N atoms and the S atom are collinear; the two S-N bonds are nonequivalent, one is much shorter (2.230 Å) than the other one (2.852 Å). In the AIM topological analysis, the interaction energy decomposition and topological properties of the electron localizability indicator (ELI-D) allowed us to categorize the stronger N-S bond in the II(D) complex as a dative bond and to assume that the fragile N-S bond is a consequence of a weak electron-donor-acceptor interaction. The calculations indicate that the identified II(D) complex corresponds to a local minimum on the PES of the NH3/SO3 system of 2:1 stoichiometry. The (NH3)2SO3 complex, II(HB), corresponding to a global minimum is 7.95 kcal mol(-1) more stable than the II(D) complex. The reason that the II(D) complex is present in the matrix but not the II(HB) complex is discussed. PMID:26447490

  6. 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.

  7. Chemical characterization of torbanites by transmission micro-FTIR spectroscopy: Origin and extent of compositional heterogeneities

    SciTech Connect

    Landais, P.; Rochdi, A. ); Largeau, C.; Derenne, S. )

    1993-06-01

    Four Permian to Carboniferous torbanites of various geographical origins were examined by transmission micro-FTIR spectroscopy on doubly polished thin sections (10--25 [mu]m). Several types of heterogeneities (different types of organic matrix; yellow and orange Botryococcus braunii colonies) were identified and chemically characterized. Important differences were noted between the organic constituents of the matrix and the algal bodies, regarding the intensity of OH, C[double bond]O, and aromatic C[double bond]C absorptions. The previous IR studies of torbanites on bulk samples therefore afforded substantially biased information on the composition of B. braunii fossil colonies, on their oil potential, and on the maturity of such kerogens. Micro-FTIR spectra indicate that the organic matrix corresponds neither to an extensive breaking up of colonies nor to humic substances. This matrix is highly heterogeneous; two types were identified in the Autun sample (chiefly corresponding to degraded algal and bacterial constituents, respectively). A precise characterization of the organic matrix was made difficult, however, in Pumpherston torbanite, due to intimate mixing with minerals. The co-occurrence of yellow and orange colonies, with contrasted micro-FTIR features, in Autun torbanite neither reflects radiolysis processes nor differences in maturation and/or source algae. A specific spatial relation was observed between these two types of algal bodies and the organo-mineral matrix, thus revealing differences in colony microenvironment after deposition. The orange colonies are likely derived, in agreement with their micro-FTIR spectra and their spatial correlation with the matrix, from sedimentological and/or matrix-catalyzed diagenetic transformations of some yellow colonies. This first application of micro-FTIR to kerogens confirmed the utility of this nondestructive, in situ pin-point method. 69 refs., 9 figs., 4 tabs.

  8. Inferences of Present and Past Changes at Isolated Enclaves and Matrix of Savannas by Carbon Isotopes in a Transitional Forest-Savanna Area in Northern Amazonia

    NASA Astrophysics Data System (ADS)

    Couto-Santos, F. R.; Luizao, F. J.; Camargo, P. B.

    2013-12-01

    The evolutionary history of savannas influenced by short term climate cycles, during the Quaternary Period, could prompt variations in forest cover often related to movements of the forest-savanna boundary. In this study we investigated current and past changes in the structure of vegetation and the origins of savannas of different natures in a biogeographically and climatic transitional forest-savanna area in northern Amazonia. Variations in the isotopic composition of soil organic matter (δ13C) from surface soils (0-10 cm) along forest-savanna boundaries, detected by a sigmoidal non-linear function, were used to identify current changes in vegetation, while past changes were inferred by discontinuities in the evolution of δ13C with soil depth using piecewise regression associated with radiocarbon dating (14C). By comparing small isolated savanna enclaves inside a strictly protected nature reserve (ESEC Maracá) with its outskirts unprotected continuous savanna matrix, we found that origins and the patterns of dynamics were distinct between these areas and did not respond in the same way to climate change and fire events, either in the last decades or during the Holocene. The stability of the present boundaries of the surrounding savanna matrix reflects the resilience of the transitional forests under a recent intensified fire regime and favorable climate, while the deep forest soil isotopic signal indicated a forest shrinkage of at least 70 m occurring since its origin in early Holocene until 780 years BP associated with a climate drier than the current one. Contrarily, the protected enclaves inside ESEC Maracá, remained stable since the middle Holocene, suggesting a non-anthropogenic origin related to soil edaphic conditions, but with recent dynamics of advancing forest by 8 m century-1 favored by current climate and lacking fire events. A detailed understanding of the origins of savannas of distinct natures and the way they are affected by climate and fire

  9. Effect of jitter on an imaging FTIR spectrometer

    SciTech Connect

    Bennett, C. L., LLNL

    1997-04-01

    Line of sight (LOS) jitter produces temporal modulations of the signals which are detected in the focal plane of a temporally modulated imaging Fourier Transform Spectrometer. A theoretical treatment of LOS jitter effects is given, and is compared with the results of measurements with LIFTIRS1 (the Livermore Imaging Fourier Transform InfraRed Spectrometer). The identification, isolation, quantification and removal of jitter artifacts in hyperspectral imaging data by means of principal components analysis is discussed. The theoretical distribution of eigenvalues expected from principal components analysis is used to determine the level of significance of spatially coherent instrumental artifacts in general, including jitter as a representative example. It is concluded that an imaging FTIR spectrometer is much less seriously impacted by a given LOS jitter level than a non imaging FTIR spectrometer.

  10. Brain mapping by FTIR microspectroscopy

    NASA Astrophysics Data System (ADS)

    Wetzel, David L.; Le Vine, Steven M.

    1992-03-01

    Spatial resolution achieved with a state-of-the-art scanning molecular FT-IR microspectrometer allows excellent spectra to be obtained from relatively small areas of 8 micrometers thick section of brain tissue. Concentration mapping is achieved by picking absorbances or baseline-corrected absorbances of select peaks for each scan obtained at a particular x,y coordinate of the tissue section. Scanning was done in the transmission mode and a programmable microscope stage was used to position the specimen in the beam between scans. The chemical selectivity of the microspectroscopic technique allowed us to superimpose chemical data onto the spatially-defined structures, particularly myelin, in the brain. Since the chemical information is both qualitative and semiquantitative the heterogeneous distribution is revealed. Previously spectroscopic analysis was performed on myelin fractions obtained from brain homogenates. This did not allows observation of localized concentration differences, as is now the case. In addition to spectra, maps of selected key wavelength responses presented from frozen sections of normal brains, result in chemically selective distribution profiles in the gray matter, white matter and basal ganglia.

  11. Isolation and characterization of a proteinaceous subnuclear fraction composed of nuclear matrix, peripheral lamina, and nuclear pore complexes from embryos of Drosophila melanogaster.

    PubMed

    Fisher, P A; Berrios, M; Blobel, G

    1982-03-01

    Morphologically intact nuclei have been prepared from embryos of Drosophila melanogaster by a simple and rapid procedure. These nuclei have been further treated with high concentrations of DNase I and RNase A followed by sequential extraction with 2% Triton X-100 and 1 M NaCl to produce a structurally and biochemically distinct preparation designated Drosophila subnuclear fraction I (DSNF-I). As seen by phase-contrast microscopy, DSNF-I is composed of material which closely resembles unfractionated nuclei; residual internal nuclear structures including nucleolar remnants are clearly visible. By transmission electron microscopy, nuclear lamina, pore complexes, and a nuclear matrix are similarly identified. Biochemically, DSNF-I is composed almost entirely of protein (greater than 93%). SDS PAGE analysis reveals several major polypeptides; species at 174,000, 74,000, and 42,000 predominate. A polypeptide coincident with the Coomassie Blue-stainable 174-kdalton band has been shown by a novel technique of lectin affinity labeling to be a glycoprotein; a glycoprotein of similar or identical molecular weight has been found to be a component of nuclear envelope fractions isolated from the livers of rats, guinea pigs, opossums, and chickens. Antisera against several of the polypeptides in DSNF-I have been obtained from rabbits, and all of them show only little or no cross-reactivity with Drosophila cytoplasmic fractions. Initial results of immunocytochemical studies, while failing to positively localize either the 174- or 16-kdalton polypeptides, demonstrate a nuclear localization of the 74-kdalton antigen in all of several interphase cell types obtained from both Drosophila embryos and third-instar larvae. PMID:6177701

  12. Matrix Isolation and Computational Study of iso-CF2Br2: a Route to Molecular Products in CF2Br2 Photolysis

    NASA Astrophysics Data System (ADS)

    George, Lisa; Kalume, Aimable; Reid, Scott A.; El-Khoury, Patrick Z.; Tarnovsky, Alexander

    2010-06-01

    The photolysis products of dibromodifluoromethane following selected wavelength laser irradiation were characterized by matrix isolation infrared and UV/Visible spectroscopy, supported by ab initio calculations. Photolysis at wavelengths of 240 and 266 nm of CF2Br2:Ar samples (1:5000) held at 5 K yielded iso-CF2Br2 (F2CBrBr), a weakly bound isomer of CF2Br2, which is characterized here for the first time. The observed infrared and UV/Visible absorptions of iso-CF2Br2 are in excellent agreement with computational predictions at the B3LYP/aug-cc-pVTZ level. Single point energy calculations at the CCSD(T)/aug-cc-pVDZ level on the B3LYP optimized geometries show that the iso-form is a minimum on the CF2Br2 potential energy surface, lying some 55 kcal/mol above the CF2Br2 ground state. The energies of various stationary points on the CF2Br2 PES were characterized computationally; taken with our experimental results, these show that iso-CF2Br2 is an intermediate in the Br + CF2Br reaction leading to molecular products (CF2 + Br2). The photochemistry of the iso-form was also investigated; excitation into the intense 359 nm absorption band resulted in isomerization to CF2Br2. Our results are discussed in view of the rich literature on the gas-phase photochemistry of CF2Br2, particularly with respect to the existence of a roaming atom pathway leading to molecular products.

  13. Matrix isolation and computational study of isodifluorodibromomethane (F2CBr-Br): A route to Br2 formation in CF2Br2 photolysis

    NASA Astrophysics Data System (ADS)

    George, Lisa; Kalume, Aimable; El-Khoury, Patrick Z.; Tarnovsky, Alexander; Reid, Scott A.

    2010-02-01

    The photolysis products of dibromodifluoromethane (CF2Br2) were characterized by matrix isolation infrared and UV/Visible spectroscopy, supported by ab initio calculations. Photolysis at wavelengths of 240 and 266 nm of CF2Br2:Ar samples (˜1:5000) held at ˜5 K yielded iso-CF2Br2 (F2CBrBr), a weakly bound isomer of CF2Br2, which is characterized here for the first time. The observed infrared and UV/Visible absorptions of iso-CF2Br2 are in excellent agreement with computational predictions at the B3LYP/aug-cc-pVTZ level. Single point energy calculations at the CCSD(T)/aug-cc-pVDZ level on the B3LYP optimized geometries suggest that the isoform is a minimum on the CF2Br2 potential energy surface, lying some 55 kcal/mol above the CF2Br2 ground state. The energies of various stationary points on the CF2Br2 potential energy surface were characterized computationally; taken with our experimental results, these show that iso-CF2Br2 is an intermediate in the Br+CF2Br→CF2+Br2 reaction. The photochemistry of the isoform was also investigated; excitation into the intense 359 nm absorption band resulted in isomerization to CF2Br2. Our results are discussed in view of the rich literature on the gas-phase photochemistry of CF2Br2, particularly with respect to the existence of a roaming atom pathway leading to molecular products.

  14. Matrix Isolation Infrared Spectroscopy of an O-H···π Hydrogen-Bonded Complex between Formic Acid and Benzene.

    PubMed

    Banerjee, Pujarini; Bhattacharya, Indrani; Chakraborty, Tapas

    2016-05-26

    Mid-infrared spectra of an O-H···π hydrogen-bonded 1:1 complex between formic acid and benzene were measured by isolating the complex in an argon matrix at a temperature of 8 K. The O-H stretching fundamental of formic acid (νO-H) undergoes a red shift of 120 cm(-1), which is the largest among the known π-hydrogen bonded complexes of an O-H donor with respect to benzene as acceptor. Electronic structure theory methods were used extensively to suggest a suitable geometry of the complex that is consistent with a recent study performed at CCSD(T)/CBS level by Zhao et al. (J. Chem. Theory Comput. 2009, 5, 2726-2733), as well as with the measured IR spectral shifts of the present study. It has been determined that density functional theory (DFT) D functionals as well as parametrized DFT functionals like M06-2X, in conjunction with modestly sized basis sets like 6-31G (d, p), are sufficient for correct predictions of the spectral shifts observed in our measurement and also for reproducing the value of the binding energy reported by Zhao et al. We also verified that these low-cost methods are sufficient in predicting the νO-H spectral shifts of an analogous O-H···π hydrogen-bonded complex between phenol and benzene. However, some inconsistencies with respect to shifts of νO-H arise when diffuse functions are included in the basis sets, and the origin of this anomaly is shown to lie in the predicted geometry of the complex. Natural bond orbital (NBO) and atoms-in-molecule (AIM) analyses were performed to correlate the spectral behavior of the complex with its geometric parameters. PMID:27163753

  15. Does a hydrogen bonded complex with dual contacts show synergism? A matrix isolation infrared and ab-initio study of propargyl alcohol-water complex

    NASA Astrophysics Data System (ADS)

    Saini, Jyoti; Viswanathan, K. S.

    2016-08-01

    When hydrogen bonded complexes are formed with more than one contact, the question arises if these multiple contacts operate synergistically. Propargyl alcohol-H2O complex presents a good case study to address this question, which is discussed in this work. Complexes of propargyl alcohol (PA) and H2O were studied experimentally using matrix isolation infrared spectroscopy, which was supported by quantum chemical computations performed at the M06-2X and MP2 level of theories, using 6-311++G (d,p) and aug-cc-pVDZ basis sets. A 1:1 PA-H2O complex was identified in the experiments and corroborated by our computations, where the PA was in the gauche conformation. This complex, which was a global minimum, showed dual interactions, one of which was an n-σ interaction between the O-H group of PA and the O of H2O, while the second was a H···​π contact between the O-H group of H2O and the π system of PA. We explored if the two interactions in the 1:1 complex exhibited synergism. We finally argue that the two interactions showed antagonism rather than synergism. Our computations indicated three other local minima for the 1:1 complexes; though these local minima were not identified in our experiments. Atoms-in-molecules and energy decomposition analysis executed through LMO-EDA were also performed to understand the nature of intermolecular interactions in the PA-H2O complexes. We have also revisited the problem of conformations of PA, with a view to understanding the reasons for gauche conformational preferences in PA.

  16. HPLC separation and FT-IR isomer differentiation of the 1,2,4,7/1,2,4,8-tetrachlorodibenzodioxin isomer pair: A theoretical/empirical approach to dibenzodioxin isomer assignmentt

    SciTech Connect

    Grainger, J.; Barnhart, E.; Patterson D.G. Jr.; Presser, D.

    1988-02-01

    The 1,2,4,7-and 1,2,4,8-tetrachlorodibenzodioxin (TCDD) isomers were separated by reversed-phase high-performance liquid chromatography (HPLC) with the use of a pyrene column. Fourier transform infrared (FT-IR) matrix isolation and vapor-phase spectra of the individual isomers were recorded. The spectra of the HPLC-seprated isomers correlate well with spectral subtraction results and were found to be distinct in three spectral regions: one of which allows for isomer structural assignment. Ambiguities and differences in published TCDD isomer FT-IR assignments are discussed in terms of a qualitative valence-bond approach and empirically derived estimates of ether linkage asymmetric stretching frequencies.

  17. Application of FTIR spectroscopy to the characterization of archeological wood

    NASA Astrophysics Data System (ADS)

    Traoré, Mohamed; Kaal, Joeri; Martínez Cortizas, Antonio

    2016-01-01

    Two archeological wood samples were studied by attenuated total reflectance Fourier transform infrared (FTIR-ATR) spectroscopy. They originate from a shipwreck in Ribadeo Bay in the northwest of Spain and from a beam wood of an old nave of the Cathedral of Segovia in the central Spain. Principal component analysis was applied to the transposed data matrix (samples as columns and spectral bands as rows) of 43 recorded spectra (18 in the shipwreck and 25 in the beam wood). The results showed differences between the two samples, with a larger proportion of carbohydrates and smaller proportion of lignin in the beam than in the shipwreck wood. Within the beam wood, lignin content was significantly lower in the recent than the old tree rings (P = 0.005). These variations can be attributed to species differences between the two woods (oak and pine respectively), with a mixture of guaiacyl and syringyl in hardwood lignin, whereas softwood lignin consists almost exclusively of guaiacyl moieties. The influence of environmental conditions on the FTIR fingerprint was probably reflected by enhanced oxidation of lignin in aerated conditions (beam wood) and hydrolysis of carbohydrates in submerged-anoxic conditions (shipwreck wood). Molecular characterization by analytical pyrolysis of selected samples from each wood type confirmed the interpretation of the mechanisms behind the variability in wood composition obtained by the FTIR-ATR.

  18. Identification of Serine Conformers by Matrix-Isolation IR Spectroscopy Aided by Near-Infrared Laser-Induced Conformational Change, 2D Correlation Analysis, and Quantum Mechanical Anharmonic Computations.

    PubMed

    Najbauer, Eszter E; Bazsó, Gábor; Apóstolo, Rui; Fausto, Rui; Biczysko, Malgorzata; Barone, Vincenzo; Tarczay, György

    2015-08-20

    The conformers of α-serine were investigated by matrix-isolation IR spectroscopy combined with NIR laser irradiation. This method, aided by 2D correlation analysis, enabled unambiguously grouping the spectral lines to individual conformers. On the basis of comparison of at least nine experimentally observed vibrational transitions of each conformer with empirically scaled (SQM) and anharmonic (GVPT2) computed IR spectra, six conformers were identified. In addition, the presence of at least one more conformer in Ar matrix was proved, and a short-lived conformer with a half-life of (3.7 ± 0.5) × 10(3) s in N2 matrix was generated by NIR irradiation. The analysis of the NIR laser-induced conversions revealed that the excitation of the stretching overtone of both the side chain and the carboxylic OH groups can effectively promote conformational changes, but remarkably different paths were observed for the two kinds of excitations. PMID:26201050

  19. FT-IR Microspectroscopy of Rat Ear Cartilage

    PubMed Central

    Vidal, Benedicto de Campos; Mello, Maria Luiza S.

    2016-01-01

    Rat ear cartilage was studied using Fourier transform-infrared (FT-IR) microspectroscopy to expand the current knowledge which has been established for relatively more complex cartilage types. Comparison of the FT-IR spectra of the ear cartilage extracellular matrix (ECM) with published data on articular cartilage, collagen II and 4-chondroitin-sulfate standards, as well as of collagen type I-containing dermal collagen bundles (CBs) with collagen type II, was performed. Ear cartilage ECM glycosaminoglycans (GAGs) were revealed histochemically and as a reduction in ECM FT-IR spectral band heights (1140–820 cm-1) after testicular hyaluronidase digestion. Although ear cartilage is less complex than articular cartilage, it contains ECM components with a macromolecular orientation as revealed using polarization microscopy. Collagen type II and GAGs, which play a structural role in the stereo-arrangement of the ear cartilage, contribute to its FT-IR spectrum. Similar to articular cartilage, ear cartilage showed that proteoglycans add a contribution to the collagen amide I spectral region, a finding that does not recommend this region for collagen type II quantification purposes. In contrast to articular cartilage, the symmetric stretching vibration of –SO3- groups at 1064 cm-1 appeared under-represented in the FT-IR spectral profile of ear cartilage. Because the band corresponding to the asymmetric stretching vibration of –SO3- groups (1236–1225 cm-1) overlapped with that of amide III bands, it is not recommended for evaluation of the –SO3- contribution to the FT-IR spectrum of the ear cartilage ECM. Instead, a peak (or shoulder) at 1027–1016 cm-1 could be better considered for this intent. Amide I/amide II ratios as calculated here and data from the literature suggest that protein complexes of the ear cartilage ECM are arranged with a lower helical conformation compared to pure collagen II. The present results could motivate further studies on this tissue

  20. FT-IR Microspectroscopy of Rat Ear Cartilage.

    PubMed

    Vidal, Benedicto de Campos; Mello, Maria Luiza S

    2016-01-01

    Rat ear cartilage was studied using Fourier transform-infrared (FT-IR) microspectroscopy to expand the current knowledge which has been established for relatively more complex cartilage types. Comparison of the FT-IR spectra of the ear cartilage extracellular matrix (ECM) with published data on articular cartilage, collagen II and 4-chondroitin-sulfate standards, as well as of collagen type I-containing dermal collagen bundles (CBs) with collagen type II, was performed. Ear cartilage ECM glycosaminoglycans (GAGs) were revealed histochemically and as a reduction in ECM FT-IR spectral band heights (1140-820 cm-1) after testicular hyaluronidase digestion. Although ear cartilage is less complex than articular cartilage, it contains ECM components with a macromolecular orientation as revealed using polarization microscopy. Collagen type II and GAGs, which play a structural role in the stereo-arrangement of the ear cartilage, contribute to its FT-IR spectrum. Similar to articular cartilage, ear cartilage showed that proteoglycans add a contribution to the collagen amide I spectral region, a finding that does not recommend this region for collagen type II quantification purposes. In contrast to articular cartilage, the symmetric stretching vibration of -SO3- groups at 1064 cm-1 appeared under-represented in the FT-IR spectral profile of ear cartilage. Because the band corresponding to the asymmetric stretching vibration of -SO3- groups (1236-1225 cm-1) overlapped with that of amide III bands, it is not recommended for evaluation of the -SO3- contribution to the FT-IR spectrum of the ear cartilage ECM. Instead, a peak (or shoulder) at 1027-1016 cm-1 could be better considered for this intent. Amide I/amide II ratios as calculated here and data from the literature suggest that protein complexes of the ear cartilage ECM are arranged with a lower helical conformation compared to pure collagen II. The present results could motivate further studies on this tissue under

  1. Understanding Why Researchers Should Use Synchrotron-Enhanced FTIR Instead of Traditional FTIR

    NASA Astrophysics Data System (ADS)

    Stem, Michelle R.

    2008-07-01

    A synchrotron-enhanced Fourier transform infrared (SR-FTIR) specializes in combining the tremendous power, brightness, intensity, focusability, and tunability of the photons radiated by a synchrotron with FTIR ability to research the vibrational properties of the lighter elements (i.e., C, N, O, etc.). Infrared (IR) wavelengths correspond to the sizes of molecular bonds having these lighter elements, and only species for which IR photons alter the molecule's dipole moment are detectable and considered to be IR responsive. SR-FTIR excels over traditional FTIR at examining the detailed properties of IR-responsive molecules. Further, SR-FTIR has superior signal-to-noise ratios, brightness, and ability to conduct long-duration scans without altering sample properties. A SR-FTIR scan can reveal exacting molecular details, unrivaled by traditional FTIR. IR-responsive species best analyzed by SR-FTIR can include trace elements, chemical structures, biological specimens, chemical reactions (pump-probe), small or dilute specimens, and molecular matrices. A SR-FTIR is especially likely to give results that have greater precision than traditional FTIR for submonolayers, polymers, semiconductors, superconductors, and environmental samples. Increasingly, the SR-FTIR is used by forensics researchers to examine potential evidentiary materials, such as drugs, paints, fibers, explosives, polymers, inks, documents, blood, and soil.

  2. Anomalous EPR intensity distribution of the methyl radical quartet adsorbed on the surface of porous materials. Comparison with solid gas matrix isolation.

    PubMed

    Benetis, Nikolas P; Dmitriev, Yurij

    2013-05-23

    The two inner lines of the EPR quartet of methyl radicals trapped in cryogenic gas matrices are superpositions of the inner transitions of an A-proton-spin quartet and an E-proton-spin doublet. Their intensity relative to the outer lines provides information on the population of the methyl-rotation quantum states. The above intensity ratio for the CH3 in solids is a challenging problem of the quantum dynamics and statistical thermodynamics. The influence of the quantum-mechanical/inertial rotation on the intensity distribution of the hf components of methyl radical on the surface of porous materials, e.g., silica gel, is investigated by EPR line shape simulations and compared with spectra of the radical isolated in the bulk of solid gas samples. The experimental part of this study includes the first in literature EPR observation of methyl radical in the bulk of N2O solid and provides new essential information on CH3 in CO2 and Ar matrices, thus, covering both strongly hindered and almost free rotation of the radical. We verify the observation of nonrotating methyl radicals in a N2O matrix, discovered earlier in cold CO2, give a thorough account of their EPR characteristics, and explore their formation at the inner surface of porous materials. Combination of a classical spin-Hamiltonian with employment of quantum effects due to nuclear spin-rotation coupling and the radical symmetry were used to interpret the experimental spectral observations. The cause of experimentally found unexpected contribution of the excited degenerate E-doublets to the EPR spectrum down to 4.2 K and A/E transition amplitude ratios sometimes as high as ca. 1:8 at liquid-N2 temperature is sought. The validity of Bose-Einstein quantum (BEq-) statistics of the spin rotation states in addition to the classical Maxwell-Boltzmann (Boltzmann) statistics was also assessed against experimental population A/E-ratio data. The BEq-statistics were not previously applied to similar systems. Furthermore

  3. Evaluation of the Bruker Biotyper Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry System for Identification of Clinical and Environmental Isolates of Burkholderia pseudomallei

    PubMed Central

    Wang, He; Chen, Ya-Lei; Teng, Shih-Hua; Xu, Zhi-Peng; Xu, Ying-Chun; Hsueh, Po-Ren

    2016-01-01

    Burkholderia pseudomallei is not represented in the current version of Bruker Biotyper matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) system. A total of 66 isolates of B. pseudomallei, including 30 clinical isolates collected from National Taiwan University Hospital (NTUH, n = 27) and Peking Union Medical College Hospital (PUMCH, n = 3), and 36 isolates of genetically confirmed strains, including 13 from clinical samples and 23 from environmental samples, collected from southern Taiwan were included in this study. All these isolates were identified by partial 16S rDNA gene sequencing analysis and the Bruker Biotyper MALDI-TOF MS system. Among the 30 isolates initially identified as B. pseudomallei by conventional identification methods, one was identified as B. cepacia complex (NTUH) and three were identified as B. putida (PUMCH) by partial 16S rDNA gene sequencing analysis and Bruker Biotyper MALDI-TOF MS system. The Bruker Biotyper MALDI-TOF MS system misidentified 62 genetically confirmed B. pseudomallei isolates as B. thailandensis or Burkholderia species (score values, 1.803–2.063) when the currently available database (DB 5627) was used. However, using a newly created MALDI-TOF MS database (including B. pseudomallei NTUH-3 strain), all isolates were correctly identified as B. pseudomallei (score values >2.000, 100%). An additional 60 isolates of genetically confirmed B. cepacia complex and B. putida were also evaluated by the Bruker Biotyper MALDI-TOF MS system using the newly created database and none of these isolates were identified as B. pseudomallei. MALDI-TOF MS is a versatile and robust tool for the rapid identification of B. pseudomallei using the enhanced database. PMID:27092108

  4. A neon-matrix isolation study of the reaction of non-energetic H-atoms with CO molecules at 3 K.

    PubMed

    Pirim, C; Krim, L

    2011-11-21

    The efficiency of HCO formation stemming from non-energetic H-atoms and CO molecules is highlighted both in the condensed phase and within a neon matrix environment, which is half-way between the condensed-phase and gas-phase. Our experiments demonstrated that HCO production within the neon-matrix needed very little or no activation energy. The efficiency of HCO formation depended only on the capability of H-atoms to diffuse in the solid and to subsequently encounter CO molecules. The novelty of the presented matrix experiment sheds light on the debated question of whether activation energy is required in order to produce HCO, because of the use of non-energetic ground state H-atoms within the neon-matrix. PMID:21960252

  5. Analyses of black fungi by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS): species-level identification of clinical isolates of Exophiala dermatitidis.

    PubMed

    Kondori, Nahid; Erhard, Marcel; Welinder-Olsson, Christina; Groenewald, Marizeth; Verkley, Gerard; Moore, Edward R B

    2015-01-01

    Conventional mycological identifications based on the recognition of morphological characteristics can be problematic. A relatively new methodology applicable for the identification of microorganisms is based on the exploitation of taxon- specific mass patterns recorded from abundant cell proteins directly from whole-cell preparations, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). This study reports the application of MALDI-TOF MS for the differentiation and identifications of black yeasts, isolated from the respiratory tracts of patients with cystic fibrosis (CF). Initial phenotypic and DNA sequence-based analyses identified these isolates to be Exophiala dermatitidis. The type strains of E. dermatitidis (CBS 207.35(T)) and other species of Exophiala were included in the MALDI-TOF MS analyses to establish the references for comparing the mass spectra of the clinical isolates of Exophiala. MALDI-TOF MS analyses exhibited extremely close relationships among the clinical isolates and with the spectra generated from the type strain of E. dermatitidis. The relationships observed between the E. dermatitidis strains from the MALDI-TOF MS profiling analyses were supported by DNA sequence-based analyses of the rRNA ITS1 and ITS2 regions. These data demonstrated the applicability of MALDI-TOF MS as a reliable, rapid and cost-effective method for the identification of isolates of E. dermatitidis and other clinically relevant fungi and yeasts that typically are difficult to identify by conventional methods. PMID:25790495

  6. Electronic Absorption Spectra of Neutral Perylene (C20H12), Terrylene (C30H16), and Quaterrylene (C40H20) and their Positive and Negative Ions: Ne Matrix-Isolation Spectroscopy and Time Dependent Density Functional Theory Calculations

    NASA Technical Reports Server (NTRS)

    Halasinski, Thomas M.; Weisman, Jennifer L.; Lee, Timothy J.; Salama, Farid; Head-Gordon, Martin; Kwak, Dochan (Technical Monitor)

    2002-01-01

    We present a full experimental and theoretical study of an interesting series of polycyclic aromatic hydrocarbons, the oligorylenes. The absorption spectra of perylene, terrylene and quaterrylene in neutral, cationic and anionic charge states are obtained by matrix-isolation spectroscopy in Ne. The experimental spectra are dominated by a bright state that red shifts with growing molecular size. Excitation energies and state symmetry assignments are supported by calculations using time dependent density functional theory methods. These calculations also provide new insight into the observed trends in oscillator strength and excitation energy for the bright states: the oscillator strength per unit mass of carbon increases along the series.

  7. Understanding Why Researchers Should Use Synchrotron-Enhanced FTIR Instead of Traditional FTIR

    ERIC Educational Resources Information Center

    Stem, Michelle R.

    2008-01-01

    A synchrotron-enhanced Fourier transform infrared (SR-FTIR) specializes in combining the tremendous power, brightness, intensity, focusability, and tunability of the photons radiated by a synchrotron with FTIR ability to research the vibrational properties of the lighter elements (i.e., C, N, O, etc.). Infrared (IR) wavelengths correspond to the…

  8. FTIR monitoring of industrial scale CVD processes

    NASA Astrophysics Data System (ADS)

    Hopfe, V.; Mosebach, H.; Meyer, M.; Sheel, D.; Grählert, W.; Throl, O.; Dresler, B.

    1998-06-01

    The goal is to improve chemical vapour deposition (CVD) and infiltration (CVI) process control by a multipurpose, knowledge based feedback system. For monitoring the CVD/CVI process in-situ FTIR spectroscopic data has been identified as input information. In the presentation, three commonly used, and distinctly different, types of industrial CVD/CVI processes are taken as test cases: (i) a thermal high capacity CVI batch process for manufacturing carbon fibre reinforced SiC composites for high temperature applications, (ii) a continuously driven CVD thermal process for coating float glass for energy protection, and (iii) a laser stimulated CVD process for continuously coating bundles of thin ceramic fibers. The feasibility of the concept with FTIR in-situ monitoring as a core technology has been demonstrated. FTIR monitoring sensibly reflects process conditions.

  9. DIFFERENTIATION OF AEROMONAS ISOLATES OBTAINED FROM DRINKING WATER DISTRIBUTION SYSTEM USING MATRIX-ASSISTED LASER DESCRIPTION/IONIZATION-MASS SPECTROMETRY (MALDI-MS)

    EPA Science Inventory

    The genus Aeromonas is one of several medically significant genera that have gained prominence due to their evolving taxonomy and controversial role in human diseases. In this study, matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) was used to analyze the...

  10. THE USE OF MATRIX-ASSISTED LASER DESORPTION/IONIZATION-MASS SPECTROMETRY FOR THE IDENTIFICATION OF AEROMONAS ISOLATES OBTAINED FROM WATER DISTRIBUTION SYSTEMS

    EPA Science Inventory

    Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) has long been established as a tool by which microorganisms can be characterized and identified. EPA is investigating the potential of using this technology as a way to rapidly identify Aeromonas species fo...

  11. Evidence of genotypic diversity among Candida auris isolates by multilocus sequence typing, matrix-assisted laser desorption ionization time-of-flight mass spectrometry and amplified fragment length polymorphism.

    PubMed

    Prakash, A; Sharma, C; Singh, A; Kumar Singh, P; Kumar, A; Hagen, F; Govender, N P; Colombo, A L; Meis, J F; Chowdhary, A

    2016-03-01

    Candida auris is a multidrug-resistant nosocomial bloodstream pathogen that has been reported from Asian countries and South Africa. Herein, we studied the population structure and genetic relatedness among 104 global C. auris isolates from India, South Africa and Brazil using multilocus sequence typing (MLST), amplified fragment length polymorphism (AFLP) fingerprinting and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). RPB1, RPB2 and internal transcribed spacer (ITS) and D1/D2 regions of the ribosomal DNA were sequenced for MLST. Further, genetic variation and proteomic assessment was carried out using AFLP and MALDI-TOF MS, respectively. Both MLST and AFLP typing clearly demarcated two major clusters comprising Indian and Brazilian isolates. However, the South African isolates were randomly distributed, suggesting different genotypes. MALDI-TOF MS spectral profiling also revealed evidence of geographical clustering but did not correlate fully with the genotyping methods. Notably, overall the population structure of C. auris showed evidence of geographical clustering by all the three techniques analysed. Antifungal susceptibility testing by the CLSI microbroth dilution method revealed that fluconazole had limited activity against 87% of isolates (MIC90, 64 mg/L). Also, MIC90 of AMB was 4 mg/L. Candida auris is emerging as an important yeast pathogen globally and requires reproducible laboratory methods for identification and typing. Evaluation of MALDI-TOF MS as a typing method for this yeast is warranted. PMID:26548511

  12. Delineation of Stenotrophomonas maltophilia isolates from cystic fibrosis patients by fatty acid methyl ester profiles and matrix-assisted laser desorption/ionization time-of-flight mass spectra using hierarchical cluster analysis and principal component analysis.

    PubMed

    Vidigal, Pedrina Gonçalves; Mosel, Frank; Koehling, Hedda Luise; Mueller, Karl Dieter; Buer, Jan; Rath, Peter Michael; Steinmann, Joerg

    2014-12-01

    Stenotrophomonas maltophilia is an opportunist multidrug-resistant pathogen that causes a wide range of nosocomial infections. Various cystic fibrosis (CF) centres have reported an increasing prevalence of S. maltophilia colonization/infection among patients with this disease. The purpose of this study was to assess specific fingerprints of S. maltophilia isolates from CF patients (n = 71) by investigating fatty acid methyl esters (FAMEs) through gas chromatography (GC) and highly abundant proteins by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and to compare them with isolates obtained from intensive care unit (ICU) patients (n = 20) and the environment (n = 11). Principal component analysis (PCA) of GC-FAME patterns did not reveal a clustering corresponding to distinct CF, ICU or environmental types. Based on the peak area index, it was observed that S. maltophilia isolates from CF patients produced significantly higher amounts of fatty acids in comparison with ICU patients and the environmental isolates. Hierarchical cluster analysis (HCA) based on the MALDI-TOF MS peak profiles of S. maltophilia revealed the presence of five large clusters, suggesting a high phenotypic diversity. Although HCA of MALDI-TOF mass spectra did not result in distinct clusters predominantly composed of CF isolates, PCA revealed the presence of a distinct cluster composed of S. maltophilia isolates from CF patients. Our data suggest that S. maltophilia colonizing CF patients tend to modify not only their fatty acid patterns but also their protein patterns as a response to adaptation in the unfavourable environment of the CF lung. PMID:25266870

  13. Swine Influenza Matrix 2 (M2) Protein Contributes to Protection Against Infection with Different H1 Swine Influenza Virus (SIV) Isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A swine influenza virus (SIV) vaccine-challenge pig model was used to study the potential of the conserved matrix 2 (M2) protein vaccine alone or in combination with an inactivated H1N1 vaccine to protect against H1N1 and H1N2 viruses. The H1N1-vaccine and heterologous H1N2-challenge virus had prev...

  14. Analyzing FTIR spectra using high sensitivity compare function of FTIR software for 2-pack epoxy paints

    NASA Astrophysics Data System (ADS)

    Saaid, Farish Irfal; Chan, Chin Han; Ong, Max Chong Hup; Winie, Tan; Harun, Mohamad Kamal

    2015-08-01

    The existing problem of oil and gas companies faced for on-site jobs of polymeric coatings on steel pipelines is that the quality of polymeric coatings varies from job to job for the same product brand from the same supplier or paint manufacturer. This can be due to the inherent problem of the reformulation of polymeric coatings or in other words adulterated polymeric coatings are supplied, where the quality of the coatings deviates from the submitted specifications for prequalification and tender purpose. Major oil and gas companies in Malaysia are calling for Coating Fingerprinting Certificate for the supply of polymeric coatings from local paint manufactures as quality assurance requirement of the coatings supplied. This will reduce the possibility of failures of the polymeric coatings, which lead to the corrosion of steel pipelines resulting in leakage of crude oil and gas to the environment. In this case, Fourier-transform infrared (FTIR) is a simple and reliable tool for coating fingerprinting. In this study, we conclude that, revelation of possible components of the 2-pack epoxy paints by carrying out extensive FTIR libraries search on FTIR spectra seems to be extremely challenging. Estimation of correlation of the sample spectrum to that of the reference spectrum using Compare function from one FTIR manufacturer, even the FTIR spectra are collected by different FTIR spectrometers from different FTIR manufacturers, can be made. The results of the correlation are reproducible.

  15. Hydration induced material transfer in membranes of osmotic pump tablets measured by synchrotron radiation based FTIR.

    PubMed

    Wu, Li; Yin, Xianzhen; Guo, Zhen; Tong, Yajun; Feng, Jing; York, Peter; Xiao, Tiqiao; Chen, Min; Gu, Jingkai; Zhang, Jiwen

    2016-03-10

    Osmotic pump tablets are reliable oral controlled drug delivery systems based on their semipermeable membrane coating. This research used synchrotron radiation-based Fourier transform infrared (SR-FTIR) microspectroscopy and imaging to investigate the hydration induced material transfer in the membranes of osmotic pump tablets. SR-FTIR was applied to record and map the chemical information of a micro-region of the membranes, composed of cellulose acetate (CA, as the water insoluble matrix) and polyethylene glycol (PEG, as the soluble pore forming agent and plasticizing agent). The microstructure and chemical change of membranes hydrated for 0, 5, 10 and 30min were measured using SR-FTIR, combined with scanning electronic microscopy and atom force microscopy. The SR-FTIR microspectroscopy results indicated that there was a major change at the absorption range of 2700-3100cm(-1) in the membranes after different periods of hydration time. The absorption bands at 2870-2880cm(-1) and 2950-2960cm(-1) were assigned to represent CA and PEG, respectively. The chemical group signal distribution illustrated by the ratio of PEG to CA demonstrated that the trigger of drug release in the preliminary stage was due to the rapid transfer of PEG into liquid medium with a sharp decrease of PEG in the membranes. The SR-FTIR mapping results have demonstrated the hydration induced material transfer in the membranes of osmotic pump tablets and enabled reassessment of the drug release mechanism of membrane controlled osmotic pump systems. PMID:26802550

  16. The effect of cooperative hydrogen bonding on the OH stretching-band shift for water clusters studied by matrix-isolation infrared spectroscopy and density functional theory.

    PubMed

    Ohno, Keiichi; Okimura, Mari; Akai, Nobuyuki; Katsumoto, Yukiteru

    2005-08-21

    Infrared spectra of the water clusters have been measured in the N2 + O2 matrix. The aggregation process of water in the matrix has been monitored by annealing the deposited samples up to 40 K and UV irradiation. The monomer, dimer, cyclic trimer and cyclic pentamer are found as water clusters in the matrix. For the hexamer, several structures such as chair, cage, prism, bag 1 and/or book 1 are likely to exist. By UV irradiation, the cyclic pentamer is predominantly formed from the monomer and dimer. On the other hand, by annealing the deposited sample, several hexamers are formed. The theoretical calculation for water clusters has revealed that the formation of one hydrogen bonding in a hydrogen-bonded chain cooperatively enhances or diminishes the strength of another hydrogen bond. Both proton donor (D) and acceptor (A) participating in a hydrogen-bonding pair DA are capable of forming hydrogen bonding with the other water molecules; D can additionally accept two protons and donate one proton, and A can additionally donate two protons and accept one proton. We have proposed the classification of hydrogen-bonding patterns considering the cooperativity, denoting as d'a'DAd''a'', where d and a are integers indicating the number of proton donors and acceptors to D (the single prime) and A (the double prime), respectively. Then, a magnitude given by MOH = -d' + a' + d'' - a'' has been introduced, which is very useful for connecting the hydrogen-bonding patterns to their OH wavenumbers. As a result, it is revealed that the OH stretching bands of water clusters are characterized by eight indicators (free and MOH = -2, -1, 0, 1, 2, 3 and 4). The classification proposed here is applicable to the OH band analysis for the hydrogen-bonded water and alcohols in a condensed phase. PMID:16186903

  17. C-Cl activation by group IV metal oxides in solid argon matrixes: matrix isolation infrared spectroscopy and theoretical investigations of the reactions of MOx (M = Ti, Zr; x = 1, 2) with CH3Cl.

    PubMed

    Zhao, Yanying

    2013-07-11

    Reactions of the ground-state titanium and zirconium monoxide and dioxide molecules with monochloromethane in excess argon matrixes have been investigated in solid argon by infrared absorption spectroscopy and density functional theoretical calculations. The results show that the ground-state MOx (M = Ti, Zr; x = 1, 2) molecules react with CH3Cl to first form the weakly bound MO(CH3Cl) and MO2(CH3Cl) complexes. The MO(CH3Cl) complexes can rearrange to the CH3M(O)Cl isomers with the Cl atom of CH3Cl coordination to the metal center of MO upon UV light irradiation (λ < 300 nm). Theoretical calculations indicate that the electronic state crossings exist from the MO + CH3Cl reaction to the more stable CH3M(O)Cl molecules via the MO(CH3Cl) complexes traversing their corresponding transition states. The MO2(CH3Cl) complexes can isomerize to the more stable CH3OM(O)Cl molecules with the addition of the C-Cl bond of CH3Cl to one of the O═M bonds of MO2 upon annealing after broad-band light irradiation. The C-Cl activation by the MOx mechanism was interpreted by the calculated potential energy profiles. PMID:23763350

  18. GHB: Forensic examination of a dangerous recreational drug by FTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Kindig, J. P.; Ellis, L. E.; Brueggemeyer, T. W.; Satzger, R. D.

    1998-06-01

    Gamma-hydroxybutyric acid (GHB) is an illegal drug that has been abused for its intoxicating effects. However, GHB can also produce harmful physiological effects ranging from mild (nausea, drowsiness) to severe (coma, death). Because GHB is often produced by clandestine manufacture, its concentration, purity, and final form can be variable. Therefore, the analysis of suspected GHB samples using FTIR spectroscopy requires a variety of sample preparations and accessories, based on the sample matrix.

  19. Isolation and characterization of a novel acidic matrix protein hic22 from the nacreous layer of the freshwater mussel, Hyriopsis cumingii.

    PubMed

    Liu, X J; Jin, C; Wu, L M; Dong, S J; Zeng, S M; Li, J L

    2016-01-01

    Matrix proteins that either weakly acidic or unusually highly acidic have important roles in shell biomineralization. In this study, we have identified and characterized hic22, a weakly acidic matrix protein, from the nacreous layer of Hyriopsis cumingii. Total protein was extracted from the nacre using 5 M EDTA and hic22 was purified using a DEAE-sepharose column. The N-terminal amino acid sequence of hic22 was determined and the complete cDNA encoding hic22 was cloned and sequenced by rapid amplification of cDNA ends-polymerase chain reaction. Finally, the localization and distribution of hic22 was determined by in situ hybridization. Our results revealed that hic22 encodes a 22-kDa protein composed of 185 amino acids. Tissue expression analysis and in situ hybridization indicated that hic22 is expressed in the dorsal epithelial cells of the mantle pallial; moreover, significant expression levels of hic22 were observed after the early formation of the pearl sac (days 19-77), implying that hic22 may play an important role in biomineralization of the nacreous layer. PMID:27525898

  20. Surface characterization of Kevlar fibers by FT-IR spectroscopy

    SciTech Connect

    Chatzi, E.G.

    1987-01-01

    The Kevlar-49 aramid fiber offers considerable potential for utilization in high-performance composite materials. However, it has poor adhesion to the polymer matrix resin. In order to improve the adhesion the surface of the fiber was characterized by using two nondestructive Fourier transform infrared (FT-IR) techniques. It was shown that the polymer chains in the skin are oriented parallel to the surface, while in the core they are almost radially oriented. This orientation as well as the fact that the functional groups are intermolecularly hydrogen-bonded might limit their availability for reacting with the polymer matrix. The author also characterized the water absorbed in both the skin and the core of the fiber and found the existence of three types of water: (a) weakly hydrogen-bonded between one NH and one carbonyl group, (b) between two carbonyl groups and (c) liquid-like water clustered in microvoids and other sites inside the fibers. It was also found that 30% of the NH groups of the Kevlar-49 fiber are accessible for deuterium exchange. These groups on one hand are available for reactions that would improve the adhesion, but on the other hand can hydrogen-bond with water, which would be detrimental for the mechanical properties of the composite.

  1. Highly automated optical characterization with FTIR spectrometry

    NASA Technical Reports Server (NTRS)

    Perry, G. L. E.; Szofran, F. R.

    1989-01-01

    The procedure for evaluating the characteristics of II-VI semiconducting infrared sensor materials with a Fourier Transform Infrared (FTIR) spectrometer system will be discussed. While the method of mapping optical characteristics with a spectrometer has been employed previously, this system is highly automated compared to other systems where the optical transmission data are obtained using a FTIR system with a small stationary aperture in the optical path and moving the specimen behind the aperture. The hardware and software, including an algorithm developed for extracting cut-on wavelengths of spectra, as well as several example results, are described to illustrate the advanced level of the system. Additionally, data from transverse slices and longitudinal wafers of the aforementioned semiconductors will be used to show the accuracy of the system in predicting trends in materials such as shapes of growth interfaces and compositional uniformity.

  2. LIFTIRS, the Livermore imaging FTIR spectrometer

    SciTech Connect

    Bennett, C.L.

    1998-06-01

    The imaging FTIR spectrometer was invented 25 years ago. Only recently, however, with the development of infrared focal plane array technology and high speed microprocessors, has the imaging FTIR spectrometer become a practical instrument. Among the class of imaging spectrometer instruments, the imaging Fourier transform spectrometer enjoys a great advantage in terms of calibratibility, sensitivity, broad band coverage and resolution flexibility. Recent experience with the LIFTIRS instrument is summarized. As a concrete example of the acquisition, calibration, and comprehension of the data from an imaging Fourier transform spectrometer, the case history of a geological sample is discussed in great detail. In particular, the importance of principle component analysis to imaging spectroscopy is especially emphasized. It is shown how the various spatial/spectral constituents within a sample can be detected, located, identified and quantified. {copyright} {ital 1998 American Institute of Physics.}

  3. ATR FTIR Mapping of Leather Fiber Panels

    NASA Astrophysics Data System (ADS)

    Tondi, G.; Grünewald, T.; Petutschnigg, A.; Schnabel, T.

    2015-01-01

    Leather fiber panels are very promising materials for many applications, not only for the easy availability of the constituents but also for their outstanding fi re-retardant properties. These innovative composite panels can be an excellent material for building insulation, and in recent times, the interest of industries in this composite board has considerably arisen. For this reason the discrimination of the components in the leather fiber panels is becoming fundamental in order to ensure their homogeneous properties. A method to characterize the surface of these materials is then required. An ATR FTIR mapping system for the leather fiber panels has been performed with a Perkin-Elmer microscope coupled with a Frontier FTIR spectrometer. The system has successfully allowed transforming the optical image to a chemical one. This technique can be considered as a right tool for routine controls of the surface quality, especially when the leather shavings cannot be optically distinguished.

  4. FT-IR : Today And Tomorrow

    NASA Astrophysics Data System (ADS)

    Grasselli, J. G.; Mehicic, M.; Mooney, J. R.

    1985-12-01

    The last decade has been a period of astonishing growth and vigor for FT-IR spectroscopy. The first International Conference on Fourier Transform Spectroscopy held in Aspen, Colorado, in 1970, described new instrumentation using Michelson interferometers that had been developed in response to problems in astro-physics, where faster acquisition of data and better ways of handling the large quantity of data generated were needed. The problems had driven the development of new instrumentation. With this impetus, instrument manufacturers introduced reliable, computerized FT-IR instruments for use by industry. These new instru-ments, with their speed and advanced data processing capabilities, led to an explosion of new examples of practical problem solving, as well as new sophistication in analyzing structures of materials or composition mixtures. Today the field of industrial infrared spectroscopy which was literally "transformed" just 15 years ago is vigorous, healthy, and still expanding. Perhaps we have now come full circle, for today industry is again articulating ever more challenging problems that need solving via novel instrumentation and/or accessories. This will lead to a tomorrow in areas that have been elegantly described in the invited lectures and poster contributions of this conference. In this paper, we will describe some typical uses of FT-IR today and from them predict where FT-IR will "walk tomorrow". We will concentrate on industrial applications because that is the community we represent. It is also relevant to point out that the growth and success of new analytical tools or techniques are dependent on the extent of use by industry. Industrial practical problem solving - and just because it's practical or solving a problem does not preclude good science and basic work - drives the development of newer and better ways to get answers to problems or to understand properties of materials.

  5. Pulsed and high-speed FTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Heussler, Sascha P.; Moser, Herbert O.; Kalaiselvi, S. M. P.; Quan, Chenggen; Tay, Cho Jui; Turaga, Shuvan P.; Breese, Mark

    2012-06-01

    Fourier transform interferometry is commonly performed by means of mechanically scanning interferometers such as a Michelson and characterized by one scanning mirror. This results in severe limitations of the capability of measuring fast signals. To overcome this drawback, we present a multi-channel FTIR spectrometer (MC-FTIR) that is capable of single-shot operation no matter how short the single pulse is, provided it delivers sufficient photons for the signal to exceed the noise. It can capture fast transient signals, limited by the signal-to-noise ratio and data transfer rate of the detector. Our device is based on a micro/nanomanufactured 3D multimirror array (MMA) which allows collecting a whole interferogram simultaneously. MMAs are manufactured by means of a patented multiple moving mask grey-level deep X-ray lithography process. Up to 640 mirror cells, generating optical path differences from 0 to about 1 mm, were achieved so far at optical quality. We have demonstrated sub-millisecond pulses and a theoretical spectral resolution of 10 cm-1 in the mid-IR. The optical system is similar to a Czerny-Turner mount with the MMA replacing the grating and an MCT focal plane array (FPA) capturing the interferogram. Our MC-FTIR enables extension of FTIR-based IR spectroscopy to arbitrarily short pulses and to fast transient signals. As the optical system is small and rugged, the instrument lends itself readily to field applications. Ongoing work is aimed at emerging applications including biomedical, laser-induced breakdown spectroscopy, and spectroscopy of synchrotron radiation.

  6. The electronic structure of VO in its ground and electronically excited states: A combined matrix isolation and quantum chemical (MRCI) study

    SciTech Connect

    Hübner, Olaf; Hornung, Julius; Himmel, Hans-Jörg

    2015-07-14

    The electronic ground and excited states of the vanadium monoxide (VO) molecule were studied in detail. Electronic absorption spectra for the molecule isolated in Ne matrices complement the previous gas-phase spectra. A thorough quantum chemical (multi-reference configuration interaction) study essentially confirms the assignment and characterization of the electronic excitations observed for VO in the gas-phase and in Ne matrices and allows the clarification of open issues. It provides a complete overview over the electronically excited states up to about 3 eV of this archetypical compound.

  7. Matrix isolation study of the mechanism of the reaction of diborane with ammonia: pyrolysis of the H 3B·NH 3 adduct

    NASA Astrophysics Data System (ADS)

    Carpenter, John D.; Ault, Bruce S.

    1992-09-01

    Gas-phase pyrolysis of the H 3B·NH 3 adduct followed by trapping of the reaction product(s) in an argon matrix at 14 K was conducted to provide support for an earlier proposed mechanism for the reaction of B 2H 6 with NH 3. As the pyrolysis temperature increased from 65 to 300°C, a decrease in yield of adduct was noted, along with a concomitant growth in H 2BNH 2. The results obtained here support a mechanism for the reaction of B 2H 6 with NH 3 in which the 1:1 adduct H 3B·NH 3 is formed in an initial slow step, and is followed by rapid elimination of H 2 to form H 2BNH 2.

  8. Isolation, proliferation, cytogenetic, and molecular characterization and in vitro differentiation potency of canine stem cells from foetal adnexa: a comparative study of amniotic fluid, amnion, and umbilical cord matrix.

    PubMed

    Filioli Uranio, M; Valentini, L; Lange-Consiglio, A; Caira, M; Guaricci, A C; L'Abbate, A; Catacchio, C R; Ventura, M; Cremonesi, F; Dell'Aquila, M E

    2011-05-01

    The possibility to isolate canine mesenchymal stem cells (MSCs) from foetal adnexa is interesting since several canine genetic disorders are reported to resemble similar dysfunctions in humans. In this study, we successfully isolated, cytogenetically and molecularly characterized, and followed the differentiation potency of canine MSCs from foetal adnexa, such as amniotic fluid (AF), amniotic membrane (AM), and umbilical cord matrix (UCM). In the three types of cell lines, the morphology of proliferating cells typically appeared fibroblast-like, and the population doubling time (DT) significantly increased with passage number. For AF- and AM-MSCs, cell viability did not change with passages. In UCM-MSCs, cell viability remained at approximately constant levels up to P6 and significantly decreased from P7 (P < 0.05). Amnion and UCM-MSCs expressed embryonic and MSC markers, such as Oct-4 CD44, CD184, and CD29, whereas AF-MSCs expressed Oct-4, CD44. Expression of the hematopoietic markers CD34 and CD45 was not found. Dog leucocyte antigens (DLA-DRA1 and DLA-79) were expressed only in AF-MSCs at P1. Isolated cells of the three cell lines at P3 showed multipotent capacity, and differentiated in vitro into neurocyte, adipocyte, osteocyte, and chondrocyte, as demonstrated by specific stains and expression of molecular markers. Cells at P4 showed normal chromosomal number, structure, and telomerase activity. These results demonstrate that, in dog, MSCs can be successfully isolated from foetal adnexa and grown in vitro. Their proven stemness and chromosomal stability indicated that MSCs could be used as a model to study stem cell biology and have an application in therapeutic programs. PMID:21491540

  9. Deciphering Host Genotype-Specific Impacts on the Metabolic Fingerprint of Listeria monocytogenes by FTIR Spectroscopy

    PubMed Central

    Grunert, Tom; Monahan, Avril; Lassnig, Caroline; Vogl, Claus; Müller, Mathias; Ehling-Schulz, Monika

    2014-01-01

    Bacterial pathogens are known for their wide range of strategies to specifically adapt to host environments and infection sites. An in-depth understanding of these adaptation mechanisms is crucial for the development of effective therapeutics and new prevention measures. In this study, we assessed the suitability of Fourier Transform Infrared (FTIR) spectroscopy for monitoring metabolic adaptations of the bacterial pathogen Listeria monocytogenes to specific host genotypes and for exploring the potential of FTIR spectroscopy to gain novel insights into the host-pathogen interaction. Three different mouse genotypes, showing different susceptibility to L. monocytogenes infections, were challenged with L. monocytogenes and re-isolated bacteria were subjected to FTIR spectroscopy. The bacteria from mice with different survival characteristics showed distinct IR spectral patterns, reflecting specific changes in the backbone conformation and the hydrogen-bonding pattern of the protein secondary structure in the bacterial cell. Coupling FTIR spectroscopy with chemometrics allowed us to link bacterial metabolic fingerprints with host infection susceptibility and to decipher longtime memory effects of the host on the bacteria. After prolonged cultivation of host-passaged bacteria under standard laboratory conditions, the host's imprint on bacterial metabolism vanished, which suggests a revertible metabolic adaptation of bacteria to host environment and loss of host environment triggered memory effects over time. In summary, our work demonstrates the potential and power of FTIR spectroscopy to be used as a fast, simple and highly discriminatory tool to investigate the mechanism of bacterial host adaptation on a macromolar and metabolic level. PMID:25541972

  10. The effect of hydrogen bonding on torsional dynamics: a combined far-infrared jet and matrix isolation study of methanol dimer.

    PubMed

    Kollipost, F; Andersen, J; Mahler, D W; Heimdal, J; Heger, M; Suhm, M A; Wugt Larsen, R

    2014-11-01

    The effect of strong intermolecular hydrogen bonding on torsional degrees of freedom is investigated by far-infrared absorption spectroscopy for different methanol dimer isotopologues isolated in supersonic jet expansions or embedded in inert neon matrices at low temperatures. For the vacuum-isolated and Ne-embedded methanol dimer, the hydrogen bond OH librational mode of the donor subunit is finally observed at ~560 cm(-1), blue-shifted by more than 300 cm(-1) relative to the OH torsional fundamental of the free methanol monomer. The OH torsional mode of the acceptor embedded in neon is observed at ~286 cm(-1). The experimental findings are held against harmonic predictions from local coupled-cluster methods with single and double excitations and a perturbative treatment of triple excitations [LCCSD(T)] and anharmonic. VPT2 corrections at canonical MP2 and density functional theory (DFT) levels in order to quantify the contribution of vibrational anharmonicity for this important class of intermolecular hydrogen bond vibrational motion. PMID:25381521

  11. The effect of hydrogen bonding on torsional dynamics: A combined far-infrared jet and matrix isolation study of methanol dimer

    SciTech Connect

    Kollipost, F.; Heger, M.; Suhm, M. A.; Andersen, J.; Mahler, D. W.; Wugt Larsen, R.; Heimdal, J.

    2014-11-07

    The effect of strong intermolecular hydrogen bonding on torsional degrees of freedom is investigated by far-infrared absorption spectroscopy for different methanol dimer isotopologues isolated in supersonic jet expansions or embedded in inert neon matrices at low temperatures. For the vacuum-isolated and Ne-embedded methanol dimer, the hydrogen bond OH librational mode of the donor subunit is finally observed at ∼560 cm{sup −1}, blue-shifted by more than 300 cm{sup −1} relative to the OH torsional fundamental of the free methanol monomer. The OH torsional mode of the acceptor embedded in neon is observed at ∼286 cm{sup −1}. The experimental findings are held against harmonic predictions from local coupled-cluster methods with single and double excitations and a perturbative treatment of triple excitations [LCCSD(T)] and anharmonic. VPT2 corrections at canonical MP2 and density functional theory (DFT) levels in order to quantify the contribution of vibrational anharmonicity for this important class of intermolecular hydrogen bond vibrational motion.

  12. Ease-of-use protocol for the rapid detection of third-generation cephalosporin resistance in Enterobacteriaceae isolated from blood cultures using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry.

    PubMed

    Foschi, C; Compri, M; Smirnova, V; Denicolò, A; Nardini, P; Tamburini, M V; Lombardo, D; Landini, M P; Ambretti, S

    2016-06-01

    An ease-of-use protocol for the identification of resistance against third-generation cephalosporins in Enterobacteriaceae isolated from blood culture bottles was evaluated using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. A cefotaxime hydrolysis assay from chocolate agar subcultures using antibiotic discs and without inoculum standardization was developed for routine work flow, with minimal hands-on time. This assay showed good performance in distinguishing between cefotaxime-susceptible and cefotaxime-resistant strains, with excellent results for Escherichia coli (sensitivity 94.7%, specificity 100%). However, cefotaxime resistance was not detected reliably in Enterobacteriaceae expressing AmpC genes or carbapenemase-producing Klebsiella pneumoniae. PMID:27105753

  13. FTIR MONITORING OF THE VENTILATION AIR OF CRITICAL BUILDINGS

    EPA Science Inventory

    Fourier transform infrared (FTIR) spectroscopy has been used for detailed analysis of environmental and industrial process samples for many years. FTIR spectrometers have the capability of measuring multiple compounds simultaneously, thus providing an advantage over most other me...

  14. Investigation of intervertebral disc degeneration using multivariate FTIR spectroscopic imaging.

    PubMed

    Mader, Kerstin T; Peeters, Mirte; Detiger, Suzanne E L; Helder, Marco N; Smit, Theo H; Le Maitre, Christine L; Sammon, Chris

    2016-06-23

    Traditionally tissue samples are analysed using protein or enzyme specific stains on serial sections to build up a picture of the distribution of components contained within them. In this study we investigated the potential of multivariate curve resolution-alternating least squares (MCR-ALS) to deconvolute 2nd derivative spectra of Fourier transform infrared (FTIR) microscopic images measured in transflectance mode of goat and human paraffin embedded intervertebral disc (IVD) tissue sections, to see if this methodology can provide analogous information to that provided by immunohistochemical stains and bioassays but from a single section. MCR-ALS analysis of non-degenerate and enzymatically in vivo degenerated goat IVDs reveals five matrix components displaying distribution maps matching histological stains for collagen, elastin and proteoglycan (PG), as well as immunohistochemical stains for collagen type I and II. Interestingly, two components exhibiting characteristic spectral and distribution profiles of proteoglycans were found, and relative component/tissue maps of these components (labelled PG1 and PG2) showed distinct distributions in non-degenerate versus mildly degenerate goat samples. MCR-ALS analysis of human IVD sections resulted in comparable spectral profiles to those observed in the goat samples, highlighting the inter species transferability of the presented methodology. Multivariate FTIR image analysis of a set of 43 goat IVD sections allowed the extraction of semi-quantitative information from component/tissue gradients taken across the IVD width of collagen type I, collagen type II, PG1 and PG2. Regional component/tissue parameters were calculated and significant correlations were found between histological grades of degeneration and PG parameters (PG1: p = 0.0003, PG2: p < 0.0001); glycosaminoglycan (GAG) content and PGs (PG1: p = 0.0055, PG2: p = 0.0001); and MRI T2* measurements and PGs (PG1: p = 0.0021, PG2: p < 0.0001). Additionally

  15. An improved method of measuring tropospheric NO2, NO3, HO2, and RO2 by Matrix Isolation and Electronic Spin Resonance (MIESR)

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The MIESR method consists of two steps (1) collection of the radicals present in the ambient air at 77K in a polycrystalline D2O matrix and (2) identification and quantification of the different radicals in the laboratory by Electron Spin Resonance spectroscopy. In step (1), the sampling efficiency for sampling NO2 and RO2 was determined to be greater than or equal to 95 percent, with a measured accuracy of plus or minus 5 percent. In step (2), after collection, the samples are maintained at 77 K and spectra are recorded in the laboratory using a standard 9.5 GHz ESR system (Varian E-line). About 50 individual scans of each spectrum are recorded and digitally averaged in order to improve the signal-to-noise ratio. The ESR-spectra are analyzed with a recently developed numerical procedure which was demonstrated to allow speciation of NO2, NO3, HO2, CH3C(O)O2, and the sum of the alkylperoxy radicals. The detection limit is 5ppt for HO2, RO2, and NO2 and 3ppt for NO3 due to its narrower ESR-linewidth.

  16. Matrix superpotentials

    NASA Astrophysics Data System (ADS)

    Nikitin, Anatoly G.; Karadzhov, Yuri

    2011-07-01

    We present a collection of matrix-valued shape invariant potentials which give rise to new exactly solvable problems of SUSY quantum mechanics. It includes all irreducible matrix superpotentials of the generic form W=kQ+\\frac{1}{k} R+P, where k is a variable parameter, Q is the unit matrix multiplied by a real-valued function of independent variable x, and P and R are the Hermitian matrices depending on x. In particular, we recover the Pron'ko-Stroganov 'matrix Coulomb potential' and all known scalar shape invariant potentials of SUSY quantum mechanics. In addition, five new shape invariant potentials are presented. Three of them admit a dual shape invariance, i.e. the related Hamiltonians can be factorized using two non-equivalent superpotentials. We find discrete spectrum and eigenvectors for the corresponding Schrödinger equations and prove that these eigenvectors are normalizable.

  17. Characterization of mannitol in Curvularia protuberata hyphae by FTIR and Raman spectromicroscopy

    USGS Publications Warehouse

    Rodriguez, Russell J.; Isenor, Merrill; Kaminsky, Susan G.W.; Redman, S.; Gough, Kathleen M.

    2010-01-01

    FTIR and Raman spectromicroscopy were used to characterize the composition of Curvularia protuberata hyphae, and to compare a strain isolated from plants inhabiting geothermal soils with a non-geothermal isolate. Thermal IR source images of hyphae have been acquired with a 64 × 64 element focal plane array detector; single point IR spectra have been obtained with synchrotron source light. In some C. protuberata hyphae, we have discovered the spectral signature of crystalline mannitol, a fungal polyol with complex protective roles. With FTIR-FPA imaging, we have determined that the protein content in cells remains fairly constant throughout the length of a hypha, whereas the mannitol is found at discrete, irregular locations. This is the first direct observation of mannitol in intact fungal hyphae. Since the concentration of mannitol in cells varies with respect to position and is not present in all hyphae, this discovery may be related to habitat adaptation, fungal structure and growth stages.

  18. Characterization of mannitol in Curvularia protuberata hyphae by FTIR and Raman spectromicroscopy

    USGS Publications Warehouse

    Isenor, M.; Kaminskyj, S.G.W.; Rodriguez, R.J.; Redman, R.S.; Gough, K.M.

    2010-01-01

    FTIR and Raman spectromicroscopy were used to characterize the composition of Curvularia protuberata hyphae, and to compare a strain isolated from plants inhabiting geothermal soils with a non-geothermal isolate. Thermal IR source images of hyphae have been acquired with a 64 ?? 64 element focal plane array detector; single point IR spectra have been obtained with synchrotron source light. In some C. protuberata hyphae, we have discovered the spectral signature of crystalline mannitol, a fungal polyol with complex protective roles. With FTIR-FPA imaging, we have determined that the protein content in cells remains fairly constant throughout the length of a hypha, whereas the mannitol is found at discrete, irregular locations. This is the first direct observation of mannitol in intact fungal hyphae. Since the concentration of mannitol in cells varies with respect to position and is not present in all hyphae, this discovery may be related to habitat adaptation, fungal structure and growth stages. ?? 2010 The Royal Society of Chemistry.

  19. Micro FT-IR Characterization Of Human Lung Tumor Cells

    NASA Astrophysics Data System (ADS)

    Benedetti, Enzo; Teodori, L.; Vergamini, Piergiorgio; Trinca, M. L.; Mauro, F.; Salvati, F.; Spremolla, Giuliano

    1989-12-01

    FT-IR spectroscopy has opened up a new approach to the analytical study of cell transformation. Investigations carried out in normal and leukemic lymphocytes have evidenced an increase in DNA with respect to proteic components in neoplastic cells.(1) The evaluation of the ratio of the integrated areas(A) of the bands at 1080 cm-1 (mainly DNA) and at 1540 cm-1 (proteic components) has allowed us to establish a parameter which indicates, for values above 1.5, the neoplastic nature of cells. Recently, this approach has been applied to the study of human lung tumor cells. Several monocellular suspension procedures of the tissue fragment (mechanical and/or chemical) were tested to obtain reproducible and reliable spectra able to differentiate clearly between normal and patological cells. Chemical treatment (EDTA, Pepsin, Collagenase, etc.) produced additional bands in the spectra of the cells causing distortion of the profiles of some absorptions, and as a result, mechanical treatment was preferred. The normal and neoplastic cells homogeneously distributed by cytospin preparation on BaF2 windows were examined by means of FT-IR microscopy. An examination of several microareas of each sample yielded reproducible spectra, with values of the A 1080 cm-1 / A 1540 cm-1 parameter within a very narrow range for each sample, even if certain differences still remained among the different cases, in good agreement with the results obtained for leukemic cells.(1) The value of this parameter was found to be lower for cells isolated from the normal area of lung, than in the case of those corresponding to the tumoral area, meaning that an increase occurs in DNA with respect to the proteic components. These insights, which provide a basis to obtain indications at the molecular level, can open up new possibilities in clinical practice, in order to obtain diagnosis confirmation, to detect early stages of disease and to offer additional indications in cases of dubious interpretation.

  20. FTIR study of primate color visual pigments

    PubMed Central

    Katayama, Kota; Kandori, Hideki

    2015-01-01

    How do we distinguish colors? Humans possess three color pigments; red-, green-, and blue-sensitive proteins, which have maximum absorbance (λmax) at 560, 530, and 420 nm, respectively, and contribute to normal human trichromatic vision (RGB). Each color pigments consists of a different opsin protein bound to a common chromophore molecule, 11-cis-retinal, whereas different chromophore-protein interactions allow preferential absorption of different colors. However, detailed experimental structural data to explain the molecular basis of spectral tuning of color pigments are lacking, mainly because of the difficulty in sample preparation. We thus started structural studies of primate color visual pigments using low-temperature Fourier-transform infrared (FTIR) spectroscopy, which needs only 0.3 mg protein for a single measurement. Here we report the first structural data of monkey red- (MR) and green- (MG) sensitive pigments, in which the information about the protein, retinal chromophore, and internal water molecules is contained. Molecular mechanism of color discrimination between red and green pigments will be discussed based on the structural data by FTIR spectroscopy. PMID:27493516

  1. FTIR analysis of Smoky Mountain aerosol

    SciTech Connect

    Blando, J.D.; Porcja, R.J.; Li, T.H.; Lioy, P.; Turpin, B.J.

    1996-12-31

    As part of the Southeastern Aerosol and Visibility Study in the Smoky Mountains (July 15-August 25, 1995), we collected samples on ZnSe discs in a Hering Low Pressure Impactor (LPI) from 7am-7pm daily. Impactor size cuts were 2.0, 1.0, 0.50, 0.26, 0.12, 0.05 um. Samples, blanks, and polystyrene standards were analyzed in a Mattson Research Series 100 FTIR Spectroscope. After initial, non-destructive analysis, a subset of samples were gently rinsed with hexane, acetone, and water in succession and analyzed by FTIR after each rinse. Sulfate and carbonyl were consistently observed in sub-micron particles, and commonly detected with soil dust in the 1-2 um size fraction. Carbonyl is associated with secondary organic aerosol formation. Aliphatics in the Smoky Mountain aerosol were most prevalent in the 1-2 um size fraction, suggesting a primary biogenic origin (e.g., plant waxes and organic acids). This contrasts with aliphatic size distributions in Los Angeles aerosols, which peaked below 0.12 um, and were attributed to automotive emissions.

  2. Sync Matrix

    Energy Science and Technology Software Center (ESTSC)

    2004-12-31

    Sync Matrix provides a graphic display of the relationships among all of the response activities of each jurisdiction. This is accomplished through software that organizes and displays the activities by jurisdiction, function, and time for easy review and analysis. The software can also integrate the displays of multiple jurisdictions to allow examination of the total response.

  3. Nano-FTIR for Geochemical Sample Analysis

    NASA Astrophysics Data System (ADS)

    Dominguez, G.; McCleod, A.; Gainsforth, Z.; Keilmann, F.; Westphal, A.; Thiemens, M. H.; Basov, D.

    2014-12-01

    Infrared (IR) spectroscopy is considered by many to be the "gold standard" for chemical identification, providing a direct connection between chemical compounds found in the laboratory and those found in natural samples including remote astrophysical environments. However, a well known limitation of using conventional IR spectroscopy is its spatial resolution determined by the wavelength of IR photons. Thus, while other techniques such as XANES and micro-Raman are capable of limited functional group mapping at tens to hundreds of nanometers, their use is limited by accessibility (the need for synchrotron beamlines) or the need for intense irradiation conditions (Raman) that can lead to sample alteration. These limitations and the wealth of information that can be extracted from detailed studies of unique micron-sized samples brought back by recent sample return missions such as NASA's Stardust mission, have motivated the development of a novel infrared mapping technique that is capable of mapping the chemical functional properties of geochemical samples with submicron resolutions. Here we describe our nano-FTIR imaging and analysis technique that allows us to bypass diffraction limited sample imaging in the infrared. Here we show, for the first time, that 1) the combination of an atomic-force microscope (AFM) and laser can be used to obtain the FTIR-equivalent spectra on spatial scales that are much smaller than the wavelength of IR radiation used 2) this technique responds to subtle shifts in cation concentrations as evidenced by changes in the frequencies of phonons at sub-micron scales 3) this technique can be used to identify regions of crystalline and semi-crystalline materials as demonstrated in our analysis of a cometary dust grain Iris. This work has clear implications for interpretations of astronomical observations and adds a new technique for the non-destructive characterization of terrestrial and extraterrestrial samples.

  4. Creation of an In-House Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Corynebacterineae Database Overcomes Difficulties in Identification of Nocardia farcinica Clinical Isolates

    PubMed Central

    Dacko, Władysław; Sikora, Joanna; Gurlaga, Danuta; Pawlik, Krzysztof; Miękisiak, Grzegorz; Gamian, Andrzej

    2015-01-01

    Nocardiosis is a rare disease that is caused by Gram-positive actinobacteria of the Nocardia genus and affects predominantly immunocompromised patients. In its disseminated form, it has a predilection for the central nervous system and is associated with high mortality rates. Therefore, prompt identification of the pathogen is critical. Matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry is a relatively novel technique used for identification of microorganisms. In this work, an upgraded MALDI-TOF Biotyper database containing Corynebacterineae representatives of strains deposited in the Polish Collection of Microorganisms was created and used for identification of the strain isolated from a nocardial brain abscess, mimicking a brain tumor, in an immunocompetent patient. Testing with the API Coryne system initially incorrectly identified Rhodococcus sp., while chemotaxonomic tests, especially mycolic acid analysis, enabled correct Nocardia identification only at the genus level. Subsequent sequence analysis of 16S rRNA and secA1 genes confirmed the identification. To improve the accuracy of the results, an in-house database was constructed using optimized parameters; with the use of the database, the strain was eventually identified as Nocardia farcinica. Clinical laboratories processing various clinical strains can upgrade a commercial database to improve and to accelerate the results obtained. This is especially important in the case of Nocardia, for which valid microbial diagnosis remains challenging; reference laboratories are often required to identify and to survey these rare actinobacteria. PMID:26041903

  5. Creation of an In-House Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Corynebacterineae Database Overcomes Difficulties in Identification of Nocardia farcinica Clinical Isolates.

    PubMed

    Paściak, Mariola; Dacko, Władysław; Sikora, Joanna; Gurlaga, Danuta; Pawlik, Krzysztof; Miękisiak, Grzegorz; Gamian, Andrzej

    2015-08-01

    Nocardiosis is a rare disease that is caused by Gram-positive actinobacteria of the Nocardia genus and affects predominantly immunocompromised patients. In its disseminated form, it has a predilection for the central nervous system and is associated with high mortality rates. Therefore, prompt identification of the pathogen is critical. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry is a relatively novel technique used for identification of microorganisms. In this work, an upgraded MALDI-TOF Biotyper database containing Corynebacterineae representatives of strains deposited in the Polish Collection of Microorganisms was created and used for identification of the strain isolated from a nocardial brain abscess, mimicking a brain tumor, in an immunocompetent patient. Testing with the API Coryne system initially incorrectly identified Rhodococcus sp., while chemotaxonomic tests, especially mycolic acid analysis, enabled correct Nocardia identification only at the genus level. Subsequent sequence analysis of 16S rRNA and secA1 genes confirmed the identification. To improve the accuracy of the results, an in-house database was constructed using optimized parameters; with the use of the database, the strain was eventually identified as Nocardia farcinica. Clinical laboratories processing various clinical strains can upgrade a commercial database to improve and to accelerate the results obtained. This is especially important in the case of Nocardia, for which valid microbial diagnosis remains challenging; reference laboratories are often required to identify and to survey these rare actinobacteria. PMID:26041903

  6. Modification of natural matrix lac-bagasse for matrix composite films

    NASA Astrophysics Data System (ADS)

    Nurhayati, Nanik Dwi; Widjaya, Karna; Triyono

    2016-02-01

    Material technology continues to be developed in order to a material that is more efficient with composite technology is a combination of two or more materials to obtain the desired material properties. The objective of this research was to modification and characterize the natural matrix lac-bagasse as composite films. The first step, natural matrix lac was changed from solid to liquid using an ethanol as a solvent so the matrix homogenly. Natural matrix lac was modified by adding citric acid with concentration variation. Secondly, the bagasse delignification using acid hydrolysis method. The composite films natural matrix lac-bagasse were prepared with optimum modified the addition citric acid 5% (v/v) and delignification bagasse optimum at 1,5% (v/v) in hot press at 80°C 6 Kg/cm-1. Thirdly, composite films without and with modification were characterized functional group analysis using FTIR spectrophotometer and mechanical properties using Universal Testing Machine. The result of research showed natural matrix lac can be modified by reaction with citric acid. FTIR spectra showed without and with modification had functional groups wide absorption 3448 cm-1 group -OH, C=O ester strong on 1712 cm-1 and the methylene group -CH2 on absorption 1465 cm-1. The mechanical properties showed tensile strength 0,55 MPa and elongation at break of 0,95 %. So that composite films natural matrix lac can be made with reinforcement bagasse for material application.

  7. FTIR microspectroscopic characterization of Spitz nevi

    NASA Astrophysics Data System (ADS)

    Giorgini, Elisabetta; Tosi, Giorgio; Conti, Carla; Staibano, Stefania; Ilardi, Gennaro; Sabbatini, Simona

    2015-04-01

    In the last 10 years, few efforts have been carried out to apply vibrational spectroscopy in the study of dermal pathologies in order to characterize the most relevant spectral markers for distinguishing benign from cancerous lesions. Spitz nevi are a special group of benign melanocytic lesions, characterized by spindled and/or epithelioid nevomelanocytes, with peculiar clinical, dermoscopic and histopathological features. The "atypical forms" of Spitz nevi are among the commonest problems of differential diagnosis with the so-called "spitzoid melanomas". The clinical and histological criteria for discriminating these two entities are very subtle and often still quite subjective, and, in a significant percentage of cases, can lead to diagnostic pitfalls and inadequate therapies. Therefore, it is noteworthy to outline that the diagnosis of melanocytic lesions still represents a challenging problem and a continue matter of discussion. We exploited FTIR microspectroscopy to study the different kinds of spitzoid melanocytes, in order to define the most relevant spectral markers of each specimen and to achieve objective information on "borderline" histologically atypical lesions. In particular, the spectroscopic investigation was carried out on melanocytes deriving from normal skin (as a normal control), malignant melanoma and Spitz nevi. The presence of the characteristic bands of melanin was investigated, too.

  8. FTIR investigation into Degradation of Natural Rubber

    NASA Astrophysics Data System (ADS)

    Rich, Ryan; Waldek Zerda, T.

    2006-10-01

    The aging of tires is of the highest concerns to the automotive industry, due to its implications in fuel economy and automobile safety. Previously, the high absorption rate of carbon black filled polymers has hindered the use of Fourier Transform Infrared Spectroscopy (FTIR) in studying this occurrence. However, recent developments in attenuated total reflection (ATR) techniques have provided a means for spectroscopically monitoring the composition changes induced in rubber blends by heat, exposure to ultra-violet radiation, and mechanical strain. The ATR apparatus, employing a germanium crystal, collected high quality infrared spectra at a reduced penetration depth of less than one micron. This research analyzed natural polymer blends with varied aggregate size and concentration of carbon black. The samples were analyzed as a function of exposure time to 70 C heat and UV radiation, as well elongation by mechanical strain. In these spectra, growth of the 1740cm-1 peak is assigned to increase populations of the C=O band. Carbon black filler rubber is shown to slow the rate of oxidation in pure natural rubber. Crystallization of rubber composites under strain is characterized by changes in the shapes of the CH stretch bands.

  9. FTIR microspectroscopic characterization of Spitz nevi.

    PubMed

    Giorgini, Elisabetta; Tosi, Giorgio; Conti, Carla; Staibano, Stefania; Ilardi, Gennaro; Sabbatini, Simona

    2015-04-15

    In the last 10 years, few efforts have been carried out to apply vibrational spectroscopy in the study of dermal pathologies in order to characterize the most relevant spectral markers for distinguishing benign from cancerous lesions. Spitz nevi are a special group of benign melanocytic lesions, characterized by spindled and/or epithelioid nevomelanocytes, with peculiar clinical, dermoscopic and histopathological features. The "atypical forms" of Spitz nevi are among the commonest problems of differential diagnosis with the so-called "spitzoid melanomas". The clinical and histological criteria for discriminating these two entities are very subtle and often still quite subjective, and, in a significant percentage of cases, can lead to diagnostic pitfalls and inadequate therapies. Therefore, it is noteworthy to outline that the diagnosis of melanocytic lesions still represents a challenging problem and a continue matter of discussion. We exploited FTIR microspectroscopy to study the different kinds of spitzoid melanocytes, in order to define the most relevant spectral markers of each specimen and to achieve objective information on "borderline" histologically atypical lesions. In particular, the spectroscopic investigation was carried out on melanocytes deriving from normal skin (as a normal control), malignant melanoma and Spitz nevi. The presence of the characteristic bands of melanin was investigated, too. PMID:25666330

  10. ADAPTING FTIR MEASUREMENT TECHNOLOGY TO HOMELAND SECURITY APPLICATIONS

    EPA Science Inventory

    Open-path Fourier transform infrared (OP-FTIR) sensors have numerous advantages for measuring chemical plumes over wide areas compared to point detection sensors. Extractive FTIR sensors have been used for industrial stack monitoring and are attractive for building ventilation sy...

  11. FTIR spectroscopy as a tool for nano-material characterization

    NASA Astrophysics Data System (ADS)

    Baudot, Charles; Tan, Cher Ming; Kong, Jeng Chien

    2010-11-01

    Covalently grafting functional molecules to carbon nanotubes (CNTs) is an important step to leverage the excellent properties of that nano-fiber in order to exploit its potential in improving the mechanical and thermal properties of a composite material. While Fourier Transform Infra Red (FTIR) spectroscopy can display the various chemical bonding in a material, we found that the existing database in FTIR library does not cover all the bonding information present in functionalized CNTs because the bond between the grafted molecule and the CNT is new in the FTIR study. In order to extend the applicability of FTIR to nano-material, we present a theoretical method to derive FTIR spectroscopy and compare it with our experimental results. In particular, we illustrate a method for the identification of functional molecules grafted on CNTs, and we are able to confirm that the functional molecules are indeed covalently grafted on the CNTs without any alterations to its functional groups.

  12. Determination of the interaction using FTIR within the composite gel polymer electrolyte

    NASA Astrophysics Data System (ADS)

    Huang, Yun; Ma, Xiaoyan; Wang, Xu; Liang, Xiao

    2013-01-01

    In the previous research, the gel polymer electrolyte (GPE) which consisted of poly(methyl methacrylate) (PMMA) matrix, propylene carbonate (PC), LiClO4 and OREC (Rectorite modified with dodecyl benzyl dimethyl ammonium chloride), achieved satisfactory properties. In the paper, the interaction between components was quantitatively determined. Characterization of interaction of Cdbnd O in PC and PMMA with Li+ and OH group on OREC surface has been thoroughly examined using FTIR, respectively. The quantitative analysis of FTIR shows that the absorptivity coefficient a of PMMA/LiClO4, PC/LiClO4, PC/OREC and PMMA/OREC is 0.902, 0.113, 0.430 and 0.753, respectively, which means that the Li+ or OH bonded Cdbnd O is more sensitive than the free Cdbnd O in FTIR spectra. The limit value of bonded Cdbnd O equivalent fraction of PMMA/LiClO4, PC/LiClO4, PC/OREC and PMMA/OREC is 17%, 94%, 57% and 20%, respectively, which implies that all the interaction within the components is reversible and the intensity of interaction is ordered as PC/LiClO4, PC/OREC, PMMA/OREC and PMMA/LiClO4.

  13. ATR-FTIR microscopy in mapping mode for the study of verdigris and its secondary products

    NASA Astrophysics Data System (ADS)

    Prati, S.; Bonacini, I.; Sciutto, G.; Genty-Vincent, A.; Cotte, M.; Eveno, M.; Menu, M.; Mazzeo, R.

    2016-01-01

    To study degradation processes occurring on painting materials, the use of high-resolution micro-analytical techniques is highly requested since it provides a detailed identification and localisation of both the original and deteriorated ingredients. Among the various pigments recently studied, the characterisation of verdigris has received a major interest. This pigment has not a unique chemical formula, but its composition depends on the recipe employed for its manufacturing. Moreover, verdigris paints are not stable and are subject to a colour change from blue-green to green, which occurs in the first few months after the application. In this paper, we focused our attention on the use of ATR-FTIR mapping as a useful method to identify verdigris secondary products and pathways. Several mock-ups and real samples have been analysed, and the correlation among the detected compounds and their spatial location, obtained by the application of ATR-FTIR microscopy in mapping mode, allowed formulating some hypotheses on the degradation pattern of verdigris, which may feed the discussion on the transformation and stability of this pigment. From an analytical point of view, we showed how FTIR mapping approaches may be extremely useful both for the identification of compounds in complex matrix in which single spectra may limit the exhaustive characterisations due to bands overlapping and for the study of degradation pathways by taking into consideration the relative distribution of degradation products.

  14. Analysis of Allergenic Pollen by FTIR Microspectroscopy.

    PubMed

    Zimmerman, B; Tafintseva, V; Bağcıoğlu, M; Høegh Berdahl, M; Kohler, A

    2016-01-01

    Fourier transform infrared (FTIR) spectroscopy is a powerful tool for the identification and characterization of pollen and spores. However, interpretation and multivariate analysis of infrared microscopy spectra of single pollen grains are hampered by Mie-type scattering. In this paper, we introduce a novel sampling setup for infrared microspectroscopy of pollens preventing strong Mie-type scattering. Pollen samples were embedded in a soft paraffin layer between two sheets of polyethylene foils without any further sample pretreatment. Single-grain infrared spectra of 13 different pollen samples, belonging to 11 species, were obtained and analyzed by the new approach and classified by sparse partial least-squares regression (PLSR). For the classification, chemical and physical information were separated by extended multiplicative signal correction and used together to build a classification model. A training set of 260 spectra and an independent test set of 130 spectra were used. Robust sparse classification models allowing the biochemical interpretation of the classification were obtained by the sparse PLSR, because only a subset of variables was retained for the analysis. With accuracy values of 95% and 98%, for the independent test set and full cross-validation respectively, the method is outperforming the previously published studies on development of an automated pollen analysis. Since the method is compatible with standard air-samplers, it can be employed with minimal modification in regular aerobiology studies. When compared with optical microscopy, which is the benchmark method in pollen analysis, the infrared microspectroscopy method offers better taxonomic resolution, as well as faster, more economical, and bias-free measurement. PMID:26599685

  15. Prepreg cure monitoring using diffuse reflectance-FTIR. [Fourier Transform Infrared Technique

    NASA Technical Reports Server (NTRS)

    Young, P. R.; Chang, A. C.

    1984-01-01

    An in situ diffuse reflectance-Fourier transform infrared technique was developed to determine infrared spectra of graphite fiber prepregs as they were being cured. A bismaleimide, an epoxy, and addition polyimide matrix resin prepregs were studied. An experimental polyimide adhesive was also examined. Samples were positioned on a small heater at the focal point of diffuse reflectance optics and programmed at 15 F/min while FTIR spectra were being scanned, averaged, and stored. An analysis of the resulting spectra provided basic insights into changes in matrix resin molecular structure which accompanied reactions such as imidization and crosslinking. An endo-exothermal isomerization involving reactive end-caps was confirmed for the addition polyimide prepregs. The results of this study contribute to a fundamental understanding of the processing of composites and adhesives. Such understanding will promote the development of more efficient cure cycles.

  16. Recent applications of ATR FTIR spectroscopy and imaging to proteins.

    PubMed

    Glassford, Stefanie E; Byrne, Bernadette; Kazarian, Sergei G

    2013-12-01

    Attenuated Total Reflection (ATR) Fourier Transform Infrared (FTIR) spectroscopy is a label-free, non-destructive analytical technique that can be used extensively to study a wide variety of different molecules in a range of different conditions. The aim of this review is to discuss and highlight the recent advances in the applications of ATR FTIR spectroscopic imaging to proteins. It briefly covers the basic principles of ATR FTIR spectroscopy and ATR FTIR spectroscopic imaging as well as their advantages to the study of proteins compared to other techniques and other forms of FTIR spectroscopy. It will then go on to examine the advances that have been made within the field over the last several years, particularly the use of ATR FTIR spectroscopy for the understanding and development of protein interaction with surfaces. Additionally, the growing potential of Surface Enhanced Infrared Spectroscopy (SEIRAS) within this area of applications will be discussed. The review includes the applications of ATR FTIR imaging to protein crystallisation and for high-throughput studies, highlighting the future potential of the technology within the field of protein structural studies and beyond. PMID:23928299

  17. Comparing FTIR and RAPD techniques in the typing of C. albicans in a clinical set-up

    NASA Astrophysics Data System (ADS)

    Sandt, Christophe L.; Sockalingum, Ganesh D.; Toubas, Dominique; Aubert, Dominique; Lepan, Herve; Lepouse, Claire; Jaussaud, Maryse; Leon, Alain; Pinon, Jean-Michel; Manfait, Michel

    2002-03-01

    Candida albicans is an opportunistic pathogen, generally though to be of endogenous origin, with however reported outbreaks. Epidemilogy of C. albicans has been studied so far by genotypic methods mainly, including the classical RAPD analysis. Albeit powerful, genotypic techniques are expensive, time consuming and complex to implement. FTIR spectroscopy is simple, rapid, inexpensive and an increasingly used technique for the identification of microorganisms. As a phenotypic method, it provides rapid whole cells 'fingerprinting' using few consumables and can detect very subtle differences between strains of the same species. In this study, C. albicans strains isolated from 50 patients from six hospital units were collected and studied by FTIR spectroscopy and RAPD-PCR. Discrimination of strains was computed using classification algorithms on selected features of the spectral data. Results from 10 patients, for whom iterative sampling was possible, are presented and discussed. Emphasis was laid on the reproducibility of dat for strain-level identification. FTIR analysis shows that (a) the C. albicans spectra were different from one patient to another, (b) seven patients exhibit each a homogeneous group while three patients display each two groups of strains. RAPD-PCR and FTIR analyses correlate quite well showing that FTIR spectroscopy could be a potential epidemiological tool in the control of nosocomial fungal infections.

  18. Rapid habitability assessment of Mars samples by pyrolysis-FTIR

    NASA Astrophysics Data System (ADS)

    Gordon, Peter R.; Sephton, Mark A.

    2016-02-01

    Pyrolysis Fourier transform infrared spectroscopy (pyrolysis FTIR) is a potential sample selection method for Mars Sample Return missions. FTIR spectroscopy can be performed on solid and liquid samples but also on gases following preliminary thermal extraction, pyrolysis or gasification steps. The detection of hydrocarbon and non-hydrocarbon gases can reveal information on sample mineralogy and past habitability of the environment in which the sample was created. The absorption of IR radiation at specific wavenumbers by organic functional groups can indicate the presence and type of any organic matter present. Here we assess the utility of pyrolysis-FTIR to release water, carbon dioxide, sulfur dioxide and organic matter from Mars relevant materials to enable a rapid habitability assessment of target rocks for sample return. For our assessment a range of minerals were analyzed by attenuated total reflectance FTIR. Subsequently, the mineral samples were subjected to single step pyrolysis and multi step pyrolysis and the products characterised by gas phase FTIR. Data from both single step and multi step pyrolysis-FTIR provide the ability to identify minerals that reflect habitable environments through their water and carbon dioxide responses. Multi step pyrolysis-FTIR can be used to gain more detailed information on the sources of the liberated water and carbon dioxide owing to the characteristic decomposition temperatures of different mineral phases. Habitation can be suggested when pyrolysis-FTIR indicates the presence of organic matter within the sample. Pyrolysis-FTIR, therefore, represents an effective method to assess whether Mars Sample Return target rocks represent habitable conditions and potential records of habitation and can play an important role in sample triage operations.

  19. Step-Scan FTIR spectroscopy and quantum chemical calculations of xanthone in the triplet state

    NASA Astrophysics Data System (ADS)

    Buschhaus, L.; Kleinermanns, K.

    2014-10-01

    Step-Scan-FTIR spectroscopy has been used to measure the infrared spectrum of xanthone in the triplet state using chloroform as solvent. Xanthone is an important triplet sensitizer and therefore suitable as model system. Xanthone was excited at 266 nm and its IR triplet spectrum measured in the range 1000-1750 cm-1. The spectrum was analyzed by comparison with DFT/B3LYP/TZVP/COSMO calculations. Further on the results were compared to gas phase IR measurements of triplet xanthone and calculations of isolated xanthone. Mainly based on the calculations we tried to identify the geometry changes from the electronic ground state to the first triplet state.

  20. Identification and differentiation of food-related bacteria: A comparison of FTIR spectroscopy and MALDI-TOF mass spectrometry.

    PubMed

    Wenning, Mareike; Breitenwieser, Franziska; Konrad, Regina; Huber, Ingrid; Busch, Ulrich; Scherer, Siegfried

    2014-08-01

    The food industry requires easy, accurate, and cost-effective techniques for microbial identification to ensure safe products and identify microbial contaminations. In this work, FTIR spectroscopy and MALDI-TOF mass spectrometry were assessed for their suitability and applicability for routine microbial diagnostics of food-related microorganisms by analyzing their robustness according to changes in incubation time and medium, identification accuracy and their ability to differentiate isolates down to the strain level. Changes in the protocol lead to a significantly impaired performance of FTIR spectroscopy, whereas they had only little effects on MALDI-TOF MS. Identification accuracy was tested using 174 food-related bacteria (93 species) from an in-house strain collection and 40 fresh isolates from routine food analyses. For MALDI-TOF MS, weaknesses in the identification of bacilli and pseudomonads were observed; FTIR spectroscopy had most difficulties in identifying pseudomonads and enterobacteria. In general, MALDI-TOF MS obtained better results (52-85% correct at species level), since the analysis of mainly ribosomal proteins is more robust and seems to be more reliable. FTIR spectroscopy suffers from the fact that it generates a whole-cell fingerprint and intraspecies diversity may lead to overlapping species borders which complicates identification. In the present study values between 56% and 67% correct species identification were obtained. On the opposite, this high sensitivity offers the opportunity of typing below the species level which was not possible using MALDI-TOF MS. Using fresh isolates from routine diagnostics, both techniques performed well with 88% (MALDI-TOF) and 75% (FTIR) correct identifications at species level, respectively. PMID:24878140

  1. Identification of Trueperella pyogenes isolated from bovine mastitis by Fourier transform infrared spectroscopy.

    PubMed

    Nagib, Samy; Rau, Jörg; Sammra, Osama; Lämmler, Christoph; Schlez, Karen; Zschöck, Michael; Prenger-Berninghoff, Ellen; Klein, Guenter; Abdulmawjood, Amir

    2014-01-01

    The present study was designed to investigate the potential of Fourier transform infrared (FT-IR) spectroscopy to identify Trueperella (T.) pyogenes isolated from bovine clinical mastitis. FT-IR spectroscopy was applied to 57 isolates obtained from 55 cows in a period from 2009 to 2012. Prior to FT-IR spectroscopy these isolates were identified by phenotypic and genotypic properties, also including the determination of seven potential virulence factor encoding genes. The FT-IR analysis revealed a reliable identification of all 57 isolates as T. pyogenes and a clear separation of this species from the other species of genus Trueperella and from species of genus Arcanobacterium and Actinomyces. The results showed that all 57 isolates were assigned to the correct species indicating that FT-IR spectroscopy could also be efficiently used for identification of this bacterial pathogen. PMID:25133407

  2. Identification of Trueperella pyogenes Isolated from Bovine Mastitis by Fourier Transform Infrared Spectroscopy

    PubMed Central

    Nagib, Samy; Rau, Jörg; Sammra, Osama; Lämmler, Christoph; Schlez, Karen; Zschöck, Michael; Prenger-Berninghoff, Ellen; Klein, Guenter; Abdulmawjood, Amir

    2014-01-01

    The present study was designed to investigate the potential of Fourier transform infrared (FT-IR) spectroscopy to identify Trueperella (T.) pyogenes isolated from bovine clinical mastitis. FT-IR spectroscopy was applied to 57 isolates obtained from 55 cows in a period from 2009 to 2012. Prior to FT-IR spectroscopy these isolates were identified by phenotypic and genotypic properties, also including the determination of seven potential virulence factor encoding genes. The FT-IR analysis revealed a reliable identification of all 57 isolates as T. pyogenes and a clear separation of this species from the other species of genus Trueperella and from species of genus Arcanobacterium and Actinomyces. The results showed that all 57 isolates were assigned to the correct species indicating that FT-IR spectroscopy could also be efficiently used for identification of this bacterial pathogen. PMID:25133407

  3. FT-IR microscopic mappings of early mineralization in chick limb bud mesenchymal cell cultures

    NASA Technical Reports Server (NTRS)

    Boskey, A. L.; Camacho, N. P.; Mendelsohn, R.; Doty, S. B.; Binderman, I.

    1992-01-01

    Chick limb bud mesenchymal cells differentiate into chondrocytes and form a cartilaginous matrix in culture. In this study, the mineral formed in different areas within cultures supplemented with 4 mM inorganic phosphate, or 2.5, 5.0, and 10 mM beta-glycerophosphate (beta GP), was characterized by Fourier-transform infrared (FT-IR) microscopy. The relative mineral-to-matrix ratios, and distribution of crystal sizes at specific locations throughout the matrix were measured from day 14 to day 30. The only mineral phase detected was a poorly crystalline apatite. Cultures receiving 4 mM inorganic phosphate had smaller crystals which were less randomly distributed around the cartilage nodules than those in the beta GP-treated cultures. beta GP-induced mineral consisted of larger, more perfect apatite crystals. In cultures receiving 5 or 10 mM beta GP, the relative mineral-to-matrix ratios (calculated from the integrated intensities of the phosphate and amide I bands, respectively) were higher than in the cultures with 4 mM inorganic phosphate or in the in vivo calcified chick cartilage.

  4. A study of Ganoderma lucidum spores by FTIR microspectroscopy

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Chen, Xianliang; Qi, Zeming; Liu, Xingcun; Li, Weizu; Wang, Shengyi

    2012-06-01

    In order to obtain unique information of Ganoderma lucidum spores, FTIR microspectroscopy was used to study G. lucidum spores from Anhui Province (A), Liaoning Province (B) and Shangdong Province (C) of China. IR micro-spectra were acquired with high-resolution and well-reproducibility. The IR spectra of G. lucidum spores from different areas were similar and mainly made up of the absorption bands of polysaccharide, sterols, proteins, fatty acids, etc. The results of curve fitting indicated the protein secondary structures were dissimilar among the above G. lucidum spores. To identify G. lucidum spores from different areas, the H1078/H1640 value might be a potentially useful factor, furthermore FTIR microspectroscopy could realize this identification efficiently with the help of hierarchical cluster analysis. The result indicates FTIR microspectroscopy is an efficient tool for identification of G. lucidum spores from different areas. The result also suggests FTIR microspectroscopy is a potentially useful tool for the study of TCM.

  5. Standardization of open-path FTIR measurements in Germany

    NASA Astrophysics Data System (ADS)

    Weber, Konradin; Eickel, Karl-Heinz

    1997-05-01

    The 'Commission of Air Pollution Prevention in VDI and DIN', which is officially responsible for the setting of written standards in the field of air pollution in Germany, has established a working group for standardization of open-path FTIR measurements in Germany. This group has presently worked out has worked out a draft for a VDI-guideline, in which it is laid down, how to perform measurements with the open-path FTIR to get reliable results.

  6. Correlating Flammability of Materials with FTIR Analysis Test Results

    NASA Technical Reports Server (NTRS)

    Moore, Robin; Whitfield, Steve

    2003-01-01

    The purpose of this experiment was to correlate flammability data with FTIR test results. Kydex 100 is a blend of chlorinated polyvinyl chloride and polymethylmethacrylate, with some filler materials. Samples supplied were 0.125 in. thick. 10 samples were taken from a sheet of Kydex and analyzed for flammability and by FTIR spectroscopy. This material was utilized as a round robin sample for flammability testing. The flammability test results were found to vary across the same sheet.

  7. FTIR and XRD study of PMMA/PCTFE blend films

    SciTech Connect

    Tripathi, S. Shripathi, T.; Tripathi, J.; Agrawal, A.; Sharma, A.

    2014-04-24

    The results are reported on solution cast PMMA-PCTFE blend films characterized using x-ray diffraction and FTIR. The nanocrystalline nature of PMMA is still seen in the blends, however, the bond modifications are clearly observed. The addition of PCTFE results in the modification in structural properties, as reflected in the XRD and FTIR spectra showing modifications in bonding as a function of PCTFE percentage.

  8. [Remote passive sensing of aeroengine exhausts using FTIR system].

    PubMed

    Xia, Qing; Zuo, Hong-Fu; Li, Shao-Cheng; Wen, Zhen-Hua; Li, Yao-Hua

    2009-03-01

    The traditional method of measuring the aeroengine exhausts is intrusive gas sampling analysis techniques. The disadvantages of the techniques include complex system, difficult operation, high costs and potential danger because of back-pressure effects. The non-intrusive methods have the potential to overcome these problems. So the remote FTIR passive sensing is applied to monitor aeroengine exhausts and determine the concentration of the exhausts gases of aeroengines. The principle of FTIR remote passive sensing is discussed. The model algorithm for the calibration of FTIR system, the radiance power distribution and gas concentration are introduced. TENSOR27 FTIR-system was used to measure the spectra of infrared radiation emitted by the hot gases of exhausts in a test rig. The emission spectra of exhausts were obtained under different thrusts. By analyzing the spectra, the concentrations of CO2, CO and NO concentration were calculated under 4 thrusts. Researches on the determination of concentration of the exhausts gases of aeroengines by using the remote FTIR sensing are still in early stage in the domestic aeronautics field. The results of the spectra and concentration in the aeroengine test are published for the first time. It is shown that the remote FTIR passive sensing techniques have a great future in monitoring the hot gas of the aeroengines exhausts. PMID:19455785

  9. [Quantitative Detection of Chinese Cabbage Clubroot Based on FTIR Spectroscopy].

    PubMed

    Wang, Wei-ping; Chai, A-li; Shi, Yan-xia; Xie, Xue-wen; Li, Bao-ju

    2015-05-01

    Clubroot, caused by Plasmodiophora brassicae, is considered the most devastating soilborne disease in Brassica crops. It has emerged as a serious disease threatening the cruciferous crop production industry in China. Nowadays, the detection techniques for P. brassicae are laborious, time-consuming and low sensitivity. Rapid and effective detection methods are needed. The objective of this study is to develop a Fourier transform infrared spectrometer (FTIR) technique for detection of P. brassicae effectively and accurately. FTIR and Real-time PCR techniques were applied in quantitative detection of P. brassicae. Chinese cabbages were inoculated with P. brassicae. By analyzing the FTIR spectra of P. brassicae, infected clubroots and healthy roots, three specific bands 1 105, 1 145 and 1 228 cm-1 were selected. According to the correlation between the peak areas at these sensitive bands and Real-time PCR Ct value, quantitative evaluation model of P. brassicae was established based on FTIR y=34. 17 +12. 24x - 9. 81x2 - 6. 05x3, r=0. 98 (p<0. 05). To validate accuracy of the model, 10 clubroot samples were selected randomly from field, and detected by FTIR spectrum model, the results showed that the average error is 1. 60%. This demonstrated that the FTIR technology is an available one for the quantitative detection of P. brassicae in clubroot, and it provides a new method for quantitative and quickly detection of Chinese cabbage clubroot. PMID:26415436

  10. [FT-IR spectroscopic analysis in monitoring of hydroxyl stretching vibrations in plant hydrogels].

    PubMed

    Pielesz, Anna; Biniaś, Dorota; Wieczorek, Joanna

    2011-01-01

    In recent years, some bioactive hydrogels isolated from natural sources have attracted much attention in the field of biochemistry and pharmacology. This article attempts to review the current structural and conformational characterization of some importantly bioactive hydrogels isolated from following plant: Symphytum officinale, Thymus pulegioides, Trigonella foenum-graecum L., Tussilago farfara L., Hyssopus officinalis, Althaea officinalis L., Equisetum arvense L. Linum usitatissimum L. and Fucus vesiculosus L. Hydrogels are cross-linked three-dimensional polysaccharide macromolecular networks that contain a large fraction of water within their structure. FT-IR spectroscopic analysis showed a strong band at 3500-3100 cm(-1) attributed to hydroxyl (the intermolecular and the intramolecular hydrogen bonds) stretching vibrations changes. PMID:22332324

  11. A rapid Fourier-transform infrared (FTIR) spectroscopic method for direct quantification of paracetamol content in solid pharmaceutical formulations

    NASA Astrophysics Data System (ADS)

    Mallah, Muhammad Ali; Sherazi, Syed Tufail Hussain; Bhanger, Muhammad Iqbal; Mahesar, Sarfaraz Ahmed; Bajeer, Muhammad Ashraf

    2015-04-01

    A transmission FTIR spectroscopic method was developed for direct, inexpensive and fast quantification of paracetamol content in solid pharmaceutical formulations. In this method paracetamol content is directly analyzed without solvent extraction. KBr pellets were formulated for the acquisition of FTIR spectra in transmission mode. Two chemometric models: simple Beer's law and partial least squares employed over the spectral region of 1800-1000 cm-1 for quantification of paracetamol content had a regression coefficient of (R2) of 0.999. The limits of detection and quantification using FTIR spectroscopy were 0.005 mg g-1 and 0.018 mg g-1, respectively. Study for interference was also done to check effect of the excipients. There was no significant interference from the sample matrix. The results obviously showed the sensitivity of transmission FTIR spectroscopic method for pharmaceutical analysis. This method is green in the sense that it does not require large volumes of hazardous solvents or long run times and avoids prior sample preparation.

  12. Are isolated wetlands isolated?

    USGS Publications Warehouse

    Smith, Loren M.; Euliss, Ned H.; Haukos, David A.

    2011-01-01

    While federal regulations during the past 10 years have treated isolated wetlands as unconnected to aquatic resources protected by the Clean Water Act, they provide critical ecosystem services to society that extend well beyond their wetland boundaries. The authors offer well-documented examples from the scientific literature on some of the ecosystem services provided by isolated wetlands to society and other ecosystems.

  13. Hybrid matrix fiber composites

    DOEpatents

    Deteresa, Steven J.; Lyon, Richard E.; Groves, Scott E.

    2003-07-15

    Hybrid matrix fiber composites having enhanced compressive performance as well as enhanced stiffness, toughness and durability suitable for compression-critical applications. The methods for producing the fiber composites using matrix hybridization. The hybrid matrix fiber composites include two chemically or physically bonded matrix materials, whereas the first matrix materials are used to impregnate multi-filament fibers formed into ribbons and the second matrix material is placed around and between the fiber ribbons that are impregnated with the first matrix material and both matrix materials are cured and solidified.

  14. FTIR spectro-imaging of collagen scaffold formation during glioma tumor development.

    PubMed

    Noreen, Razia; Chien, Chia-Chi; Chen, Hsiang-Hsin; Bobroff, Vladimir; Moenner, Michel; Javerzat, Sophie; Hwu, Yeukuang; Petibois, Cyril

    2013-11-01

    Evidence has recently emerged that solid and diffuse tumors produce a specific extracellular matrix (ECM) for division and diffusion, also developing a specific interface with microvasculature. This ECM is mainly composed of collagens and their scaffolding appears to drive tumor growth. Although collagens are not easily analyzable by UV-fluorescence means, FTIR imaging has appeared as a valuable tool to characterize collagen contents in tissues, specially the brain, where ECM is normally devoid of collagen proteins. Here, we used FTIR imaging to characterize collagen content changes in growing glioma tumors. We could determine that C6-derived solid tumors presented high content of triple helix after 8-11 days of growth (typical of collagen fibrils formation; 8/8 tumor samples; 91 % of total variance), and further turned to larger α-helix (days 12-15; 9/10 of tumors; 94 % of variance) and β-turns (day 18-21; 7/8 tumors; 97 % of variance) contents, which suggest the incorporation of non-fibrillar collagen types in ECM, a sign of more and more organized collagen scaffold along tumor progression. The growth of tumors was also associated to the level of collagen produced (P < 0.05). This study thus confirms that collagen scaffolding is a major event accompanying the angiogenic shift and faster tumor growth in solid glioma phenotypes. PMID:24068168

  15. Thermal decomposition behaviors of lignite by pyrolysis-FTIR

    SciTech Connect

    Feng, J.; Li, W.Y.; Xie, K.C.

    2006-01-21

    An in situ pyrolysis reactor combined with the Fourier transformation infrared spectrometer (PFTIR) technique is employed to study the coal structure and its thermal decomposition behaviors. The interface of pyroprobe with FTIR was designed delicately to ensure the path of the laser beam in FTIR was just 3 {mu}m above the coal sample, so any detection information of products from coal pyrolysis would be acquired previous to the secondary reaction. The PFTIR technique can be adopted to determine the activation energy of coal pyrolysis. Lignite coal has been used to evaluate this new method. The thermal decomposition behaviors of functional groups from lignite pyrolysis coincide with the first-order reaction.

  16. The quantitative analysis of OH in vesuvianite: a polarized FTIR and SIMS study

    NASA Astrophysics Data System (ADS)

    Bellatreccia, Fabio; della Ventura, Giancarlo; Ottolini, Luisa; Libowitzky, Eugen; Beran, Anton

    2005-05-01

    A well-characterized suite of vesuvianite samples from the volcanic ejecta (skarn or syenites) from Latium (Italy) was studied by single-crystal, polarized radiation, Fourier-transform infrared (FTIR) spectroscopy and secondary-ion mass-spectrometry (SIMS). OH-stretching FTIR spectra consist of a rather well-defined triplet of broad bands at higher-frequency (3,700 3,300 cm-1) and a very broad composite absorption below 3,300 cm-1. Measurements with E//c or E⊥c show that all bands are strongly polarized with maximum absorption for E//c. They are in agreement with previous band assignments (Groat et al. Can Mineral 33:609, 1995) to the two O(11) H(1) and O(10) H(2) groups in the structure. Pleochroic measurements with changing direction of the E vector of the incident radiation show that the orientation of the O(11) H(1) dipole is OH∧c~35°, in excellent agreement with the neutron data of Lager et al. (Can Mineral 37:763, 1999). A SIMS-based calibration curve at ~10% rel. accuracy has been worked out and used as reference for the quantitative analysis of H2O in vesuvianite by FTIR. Based on previous SIMS results for silicate minerals (Ottolini and Hawthorne in J Anal At Spectrom 16:1266, 2001; Ottolini et al. in Am Mineral 87:1477, 2002) the SiO2 and FeO content of the matrix were assumed as the major factors to be considered at a first approximation in the selection of the standards for H. The lack of vesuvianite standards for quantitative SIMS analysis of H2O has been here overcome by selecting low-silica elbaite crystals (Ottolini et al. in Am Mineral 87:1477, 2002). The resulting integrated molar absorption FTIR coefficient for vesuvianite is ɛi=100.000±2.000 l mol-1 cm-2. SIMS data for Li, B, F, Sr, Y, Be, Ba REE, U and Th are also provided in the paper.

  17. FTIR Laboratory in Support of the PV Program

    SciTech Connect

    Keyes, B. M.; Gedvilas, L. M.; Bhattacharya, R.; Xu, Y.; Li, X.; Wang, Q.

    2005-01-01

    The Fourier Transform Infrared Spectroscopy (FTIR) Laboratory supports the Solar Energy Technologies Program through the measurement and characterization of solar energy-related materials and devices. The FTIR technique is a fast, accurate, and reliable method for studying molecular structure and composition. This ability to identify atomic species and their bonding environment is a powerful combination that finds use in many research and development efforts. A brief overview of the technical approach used is contained in Section 2 of this report. Because of its versatility and accessibility, the FTIR Laboratory is a valuable contributor to the Solar Energy Technologies Program. The laboratory provides support for, and collaborates with, several in-house programs as well as our industry and university partners. By the end of FY 2004, the FTIR Laboratory performed over 1100 measurements on PV-related materials. These contributions resulted in conference and workshop presentations and several peer-reviewed publications. A brief summary of a few of these efforts is contained in Section 3 of this report.

  18. Raman and FTIR microspectroscopy for detection of brain metastasis

    NASA Astrophysics Data System (ADS)

    Bergner, Norbert; Romeike, Bernd F. M.; Reichart, Rupert; Kalff, Rolf; Krafft, Christoph; Popp, Jürgen

    2011-07-01

    Vibrational spectroscopic imaging methods are novel tools to visualise chemical component in tissue without staining. Fourier transform infrared (FTIR) imaging is more frequently applied than Raman imaging so far. FTIR images recorded with a FPA detector have been demonstrated to identify the primary tumours of brain metastases. However, the strong absorption of water makes it difficult to transfer the results to non-dried tissues. Raman spectroscopy with near infrared excitation can be used instead and allows collecting the chemical fingerprint of native specimens. Therefore, Raman spectroscopy is a promising tool for tumour diagnosis in neurosurgery. Scope of the study is to compare FTIR and Raman images to visualize the tumour border and identify spectral features for classification. Brain metastases were obtained from patients undergoing surgery at the university hospital. Brain tissue sections were shock frozen, cryosectioned, dried and the same areas were imaged with both spectroscopic method. To visualise the chemical components, multivariate statistical algorithms were applied for data analysis. Furthermore classification models were trained using supervised algorithms to predict the primary tumor of brain metastases. Principal component regression (PCR) was used for prediction based on FTIR images. Support vector machines (SVM) were used for prediction based on Raman images. The principles are shown for two specimens. In the future, the study will be extended to larger data sets.

  19. FT-IR spectroscopy characterization of schwannoma: a case study

    NASA Astrophysics Data System (ADS)

    Ferreira, Isabelle; Neto, Lazaro P. M.; das Chagas, Maurilio José; Carvalho, Luís. Felipe C. S.; dos Santos, Laurita; Ribas, Marcelo; Loddi, Vinicius; Martin, Airton A.

    2016-03-01

    Schwannoma are rare benign neural neoplasia. The clinical diagnosis could be improved if novel optical techniques are performed. Among these techniques, FT-IR is one of the currently techniques which has been applied for samples discrimination using biochemical information with minimum sample preparation. In this work, we report a case of a schwannoma in the cervical region. A histological examination described a benign process. An immunohistochemically examination demonstrated positivity to anti-S100 protein antibody, indicating a diagnosis of schwannoma. The aim of this analysis was to characterize FT-IR spectrum of the neoplastic and normal tissue in the fingerprint (1000-1800 cm-1) and high wavenumber region (2800-3600 cm-1). The IR spectra were collect from tumor tissue and normal nerve samples by a FT-IR spectrophotometer (Spotlight Perkin Elmer 400, USA) with 64 scans, and resolution of 4 cm-1. A total of twenty spectra were recorded (10 from schwannoma and 10 from nerve). Multivariate Analysis was used to classify the data. Through average and standard deviation analysis we observed that the main spectral change occurs at ≍1600 cm-1 (amide I) and ≍1400 cm-1 (amide III) in the fingerprint region, and in CH2/CH3 protein-lipids and OH-water vibrations for the high wavenumber region. In conclusion, FT-IR could be used as a technique for schwannoma analysis helping to establish specific diagnostic.

  20. Nano-FTIR chemical mapping of minerals in biological materials

    PubMed Central

    Amarie, Sergiu; Zaslansky, Paul; Kajihara, Yusuke; Griesshaber, Erika; Schmahl, Wolfgang W

    2012-01-01

    Summary Methods for imaging of nanocomposites based on X-ray, electron, tunneling or force microscopy provide information about the shapes of nanoparticles; however, all of these methods fail on chemical recognition. Neither do they allow local identification of mineral type. We demonstrate that infrared near-field microscopy solves these requirements at 20 nm spatial resolution, highlighting, in its first application to natural nanostructures, the mineral particles in shell and bone. "Nano-FTIR" spectral images result from Fourier-transform infrared (FTIR) spectroscopy combined with scattering scanning near-field optical microscopy (s-SNOM). On polished sections of Mytilus edulis shells we observe a reproducible vibrational (phonon) resonance within all biocalcite microcrystals, and distinctly different spectra on bioaragonite. Surprisingly, we discover sparse, previously unknown, 20 nm thin nanoparticles with distinctly different spectra that are characteristic of crystalline phosphate. Multicomponent phosphate bands are observed on human tooth sections. These spectra vary characteristically near tubuli in dentin, proving a chemical or structural variation of the apatite nanocrystals. The infrared band strength correlates with the mineral density determined by electron microscopy. Since nano-FTIR sensitively responds to structural disorder it is well suited for the study of biomineral formation and aging. Generally, nano-FTIR is suitable for the analysis and identification of composite materials in any discipline, from testing during nanofabrication to even the clinical investigation of osteopathies. PMID:22563528

  1. Nano-FTIR chemical mapping of minerals in biological materials.

    PubMed

    Amarie, Sergiu; Zaslansky, Paul; Kajihara, Yusuke; Griesshaber, Erika; Schmahl, Wolfgang W; Keilmann, Fritz

    2012-01-01

    Methods for imaging of nanocomposites based on X-ray, electron, tunneling or force microscopy provide information about the shapes of nanoparticles; however, all of these methods fail on chemical recognition. Neither do they allow local identification of mineral type. We demonstrate that infrared near-field microscopy solves these requirements at 20 nm spatial resolution, highlighting, in its first application to natural nanostructures, the mineral particles in shell and bone. "Nano-FTIR" spectral images result from Fourier-transform infrared (FTIR) spectroscopy combined with scattering scanning near-field optical microscopy (s-SNOM). On polished sections of Mytilus edulis shells we observe a reproducible vibrational (phonon) resonance within all biocalcite microcrystals, and distinctly different spectra on bioaragonite. Surprisingly, we discover sparse, previously unknown, 20 nm thin nanoparticles with distinctly different spectra that are characteristic of crystalline phosphate. Multicomponent phosphate bands are observed on human tooth sections. These spectra vary characteristically near tubuli in dentin, proving a chemical or structural variation of the apatite nanocrystals. The infrared band strength correlates with the mineral density determined by electron microscopy. Since nano-FTIR sensitively responds to structural disorder it is well suited for the study of biomineral formation and aging. Generally, nano-FTIR is suitable for the analysis and identification of composite materials in any discipline, from testing during nanofabrication to even the clinical investigation of osteopathies. PMID:22563528

  2. NARSTO EPA SS HOUSTON TEXAQS2000 PM FTIR

    Atmospheric Science Data Center

    2014-04-25

    NARSTO EPA SS HOUSTON TEXAQS2000 PM FTIR Project Title:  NARSTO ... Transform Infrared Spectrometer) Location:  Houston, Texas Spatial Resolution:  Point Measurements ...   Order Data Guide Documents:  Houston TexAQS2000 PM Guide Houston Project Plan  (PDF) ...

  3. Low-cost OP-FTIR spectrometer for workplace monitoring

    NASA Astrophysics Data System (ADS)

    Rentz, Julia H.; Engel, James R.; Carlson, David L.; Mansur, David J.; Vaillancourt, Robert M.; Genetti, George J.; Griffiths, Peter R.; Yang, Husheng

    2004-03-01

    OPTRA has developed a low-cost, extremely compact, rugged open-path Fourier transform infrared (OP-FTIR) spectrometer for workplace air quality monitoring. This research was funded under a United States Air Force ABIR Phase II contract. The goal of the program has been to identify and alleviate all aspects of currently available OP-FTIR systems which result in high-cost and complex user requirements. This low-resolution ssytem (Δσ = 8 cm-1) employs an uncooled DLATGS detector and a novel encoder-based reference metrology. Other design economies include a plastic injection-molded retroreflector array to return the open-path beam. This effort has included the development of a set of algorithms based on artificial neural networks (ANNs) and partial least squares (PLS) by the University of Idaho; these algorithms are specifically tailored to low-resolution systems applied to multi-component analysis of large, organic molecules characterized by broad infrared resonance bands. The algorithms, coupled with our OP-FTIR, are designed to autonomously identify and quantify a list of 105 common industrial organic molecules in the presence of varying humidity levels. Our system includes two PCI boards which host all OP-FTIR processing and servo electronics; the boards reside in a small suit-case PC along with a user-friendly Graphical User Interface.

  4. Miniaturized FTIR-spectrometer based on optical MEMS translatory actuator

    NASA Astrophysics Data System (ADS)

    Sandner, Thilo; Kenda, Andreas; Drabe, Christian; Schenk, Harald; Scherf, Werner

    2007-01-01

    In this paper we present a MOEMS based miniaturized Fourier-transform infrared (FTIR) spectrometer capable to perform time resolved measurements from NIR to MIR. The FTIR-spectrometer is based on a MOEMS translatory actuator which replaces the macroscopic mirror drive enabling a miniaturized, robust and low cost FTIR system. The MOEMS device is manufactured in a CMOS compatible process using SOI technology. Due to the electrostatic driving principle based on in-plane electrode combs, 200 μm stroke can be achieved with comparatively low voltages (<40 V) at an ambient pressure below 500 Pa. The actuator plate, acting as mirror with an area of 1.65 mm2, operates at a resonant frequency of 5 kHz. Consequently this yields a maximum spectral resolution of 25 cm -1 and an acquisition time of 200 μs per spectrum. Based on a Michelson setup the infrared optical bench of the presented FTIR system is designed to account for the mirror aperture and the desired spectral bandwidth of 2 μm to 5 μm. The integrated signal processing electronics has to cope with a bandwidth of 8 MHz as a result of the mirror motion. A digital signal processor manages system control and data processing. The high acquisition rate and integration level of the system makes it appropriate for applications like process control and surveillance of fast reactions. First results of transmission and absorbance measurements are shown. In addition we present a novel MOEMS device with increased mirror aperture and stroke which will be used for further optimization of the spectral FTIR-resolution.

  5. Prion structure investigated in situ, ex vivo, and in vitro by FTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Kneipp, Janina; Miller, Lisa M.; Spassov, Sashko; Sokolowski, Fabian; Lasch, Peter; Beekes, Michael; Naumann, Dieter

    2004-07-01

    Syrian hamster nervous tissue was investigated by FTIR microspectroscopy with conventional and synchrotron infrared light sources. Various tissue structures from the cerebellum and medulla oblongata of scrapie-infected and control hamsters were investigated at a spatial resolution of 50 μm. Single neurons in dorsal root ganglia of scrapie-infected hamsters were analyzed by raster scan mapping at 6 μm spatial resolution. These measurements enabled us to (i) scrutinize structural differences between infected and non-infected tissue and (ii) analyze for the first time the distribution of different protein structures in situ within single nerve cells. Single nerve cells exhibited areas of increased β-sheet content, which co-localized consistently with accumulations of the pathological prion protein (PrPSc). Spectral data were also obtained from purified, partly proteinase K digested PrPSc isolated from scrapie-infected nervous tissue of hamsters to elucidate similarities/dissimilarities between prion structure in situ and ex vivo. A further comparison is drawn to the recombinant Syrian hamster prion protein SHaPrP90-232, whose in vitro transition from the predominantly a-helical isoform to β-sheet rich oligomeric structures was also investigated by FTIR spectroscopy.

  6. Application of Fourier Transform Infrared (FTIR) Spectroscopy for Rapid Detection of Fumonisin B2 in Raisins.

    PubMed

    Heperkan, Dilek; Gökmen, Ece

    2016-07-01

    The aim of this study was to investigate the potential use of FTIR spectroscopy as a rapid screening method to detect fumonisin produced by Aspergillus niger. A. niger spore suspensions isolated from raisins were inoculated in Petri dishes prepared with sultana raisin or black raisin extracts containing agar and malt extract agar (MEA). After 9 days of incubation at 25°C, fumonisin B2 (FB2) production on each agar plate was determined by subjecting the agar plugs to IR spectroscopy. The presence of amino group (at 1636-1639 cm(-1)) was especially indicative of fumonisin production in MEA and the raisin extracts containing agar. The results were confirmed by HPLC analysis of the agar sample extracts after immunoaffinity column cleanup. It was determined that A. niger produced more FB2 in sultana raisins than in MEA, with no FB2 being produced in black raisin extract agar. This study demonstrated that proper sample preparation procedure followed by FTIR analysis is a useful technique for identifying toxigenic molds and their mycotoxin production in agricultural commodities. PMID:27455931

  7. Study of Kerogen Maturity using Transmission Fourier Transform Infrared Spectroscopy (FTIR)

    NASA Astrophysics Data System (ADS)

    Dang, S. T.

    2014-12-01

    Maturity of kerogen in shale governs the productivity and generation hydrocarbon type. There are generally two accepted methods to measure kerogen maturity; one is the measurement of vitrinite reflectance, %Ro, and another is the measurement of Tmax through pyrolysis. However, each of these techniques has its own limits; vitrinite reflectance measurement cannot be applied to marine shale and pre-Silurian shales, which lack plant materials. Furthermore, %Ro, requires the isolation and identification of vitrinite macerals and statistical measurements of at least 50 macerals. Tmax measurement is questionable for mature and post-mature samples. In addition, there are questions involving the effects of solvents on Tmax determinations. Fourier Transmission Infrared Spectroscopy, FTIR, can be applied for both qualitative and quantitative assessment on organics maturity in shale. The technique does not require separating organic matter or identifying macerals. A CH2/CH3 index, RCH, calculated from FTIR spectra is more objective than other measurements. The index increases with maturity (both natural maturation and synthetic maturation through hydrous and dry pyrolysis). The new maturity index RCH can be calibrated to vitrinite reflectance which allows the definition of the following values for levels of maturity: 1) immature—RCH > 1.6±0.2; 2) oil window-- 1.6±0.2 < RCH > 1.3±0.3; 3) wet gas window--1.3±0.3 < RCH> 1.13±0.05; and 4) dry gas window RCH < 1.13±0.05.

  8. Insufficient Discriminatory Power of Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry Dendrograms to Determine the Clonality of Multi-Drug-Resistant Acinetobacter baumannii Isolates from an Intensive Care Unit

    PubMed Central

    Rim, John Hoon; Hong, Sung Kuk; Park, Yongjung; Kim, MyungSook; D'Souza, Roshan; Park, Eun Suk; Yong, Dongeun; Lee, Kyungwon

    2015-01-01

    While pulsed-field gel electrophoresis (PFGE) is recognized as the gold standard method for clonality analysis, MALDI-TOF MS has recently been spotlighted as an alternative tool for species identification. Herein, we compared the dendrograms of multi-drug-resistant (MDR) Acinetobacter baumannii isolates by using MALDI-TOF MS with those by using PFGE. We used direct colony and protein extraction methods for MALDI-TOF MS dendrograms. The isolates with identical PFGE patterns were grouped into different branches in MALDI-TOF MS dendrograms. Among the isolates that were classified as very close isolates in MALDI-TOF MS dendrogram, PFGE band patterns visually showed complete differences. We numeralized similarity among isolates by measuring distance levels. The Spearman rank correlation coefficient values were 0.449 and 0.297 between MALDI-TOF MS dendrogram using direct colony and protein extraction method versus PFGE, respectively. This study is the first paper focusing solely on the dendrogram function of MALDI-TOF MS compared with PFGE. Although MALDI-TOF MS is a promising tool to identify species in a rapid manner, our results showed that MALDI-TOF MS dendrograms could not substitute PFGE for MDR Acinetobacter baumannii clonality analysis. PMID:26101775

  9. A matrix lower bound

    SciTech Connect

    Grcar, Joseph F.

    2002-02-04

    A matrix lower bound is defined that generalizes ideas apparently due to S. Banach and J. von Neumann. The matrix lower bound has a natural interpretation in functional analysis, and it satisfies many of the properties that von Neumann stated for it in a restricted case. Applications for the matrix lower bound are demonstrated in several areas. In linear algebra, the matrix lower bound of a full rank matrix equals the distance to the set of rank-deficient matrices. In numerical analysis, the ratio of the matrix norm to the matrix lower bound is a condition number for all consistent systems of linear equations. In optimization theory, the matrix lower bound suggests an identity for a class of min-max problems. In real analysis, a recursive construction that depends on the matrix lower bound shows that the level sets of continuously differential functions lie asymptotically near those of their tangents.

  10. Preparation of on-plate immobilized metal ion affinity chromatography platform via dopamine chemistry for highly selective isolation of phosphopeptides with matrix assisted laser desorption/ionization mass spectrometry analysis.

    PubMed

    Shi, Chenyi; Lin, Qinrui; Deng, Chunhui

    2015-04-01

    In this study, a novel on-plate IMAC technique was developed for highly selective enrichment and isolation of phosphopeptides with high-throughput MALDI-TOF-MS analysis. At first, a MALDI plate was coated with polydopamine (PDA), and then Ti(4+) was immobilized on the PDA-coated plate. The obtained IMAC plate was successfully applied to the highly selective enrichment and isolation of phosphopeptides in protein digests and human serum. Because of no loss of samples, the on-plate IMAC platform exhibits excellent selectivity and sensitivity in the selective enrichment and isolation of phosphopeptides, which provides a potential technique for high selectivity in the detection of low-abundance phosphopeptides in biological samples. PMID:25640129

  11. FT-IR spectroscopy of lipoproteins—A comparative study

    NASA Astrophysics Data System (ADS)

    Krilov, Dubravka; Balarin, Maja; Kosović, Marin; Gamulin, Ozren; Brnjas-Kraljević, Jasminka

    2009-08-01

    FT-IR spectra, in the frequency region 4000-600 cm -1, of four major lipoprotein classes: very low density lipoprotein (VLDL), low density lipoprotein (LDL) and two subclasses of high density lipoproteins (HDL 2 and HDL 3) were analyzed to obtain their detailed spectral characterization. Information about the protein domain of particle was obtained from the analysis of amide I band. The procedure of decomposition and curve fitting of this band confirms the data already known about the secondary structure of two different apolipoproteins: apo A-I in HDL 2 and HDL 3 and apo B-100 in LDL and VLDL. For information about the lipid composition and packing of the particular lipoprotein the well expressed lipid bands in the spectra were analyzed. Characterization of spectral details in the FT-IR spectrum of natural lipoprotein is necessary to study the influence of external compounds on its structure.

  12. Environment Polarity in Proteins Mapped Noninvasively by FTIR Spectroscopy

    PubMed Central

    Manor, Joshua; Feldblum, Esther S.; Zanni, Martin T.; Arkin, Isaiah T.

    2012-01-01

    The polarity pattern of a macromolecule is of utmost importance to its structure and function. For example, one of the main driving forces for protein folding is the burial of hydrophobic residues. Yet polarity remains a difficult property to measure experimentally, due in part to its non-uniformity in the protein interior. Herein, we show that FTIR linewidth analysis of noninvasive 1-13C=18O labels can be used to obtain a reliable measure of the local polarity, even in a highly multi-phasic system, such as a membrane protein. We show that in the Influenza M2 H+ channel, residues that line the pore are located in an environment that is as polar as fully solvated residues, while residues that face the lipid acyl chains are located in an apolar environment. Taken together, FTIR linewidth analysis is a powerful, yet chemically non-perturbing approach to examine one of the most important properties in proteins - polarity. PMID:22563521

  13. Characterization of Combinatorial Polymer Blend Composition Gradients by FTIR Microspectroscopy

    PubMed Central

    Eidelman, Naomi; Simon, Carl G.

    2004-01-01

    A new FTIR technique was developed for characterizing thin polymer films used in combinatorial materials science. Fourier transform infrared microspectroscopy mapping technique was used to determine the composition of polymer blend gradients. Composition gradients were made from poly(L-lactic acid) (PLLA) and poly(D,L-lactic acid) (PDLLA) in the form of thin films (6 cm × 2 cm) deposited on IR reflective substrates. Three composition gradient films were prepared and characterized. The results demonstrate the reproducibility and feasibility of a new, high-throughput approach for preparing and characterizing polymer composition gradients. The combination of composition gradient film technology and automated nondestructive FTIR microspectroscopy makes it possible to rapidly and quantitatively characterize polymer composition gradients for use in combinatorial materials science. PMID:27366606

  14. Image reconstruction of FT-IR microspectrometric data

    NASA Astrophysics Data System (ADS)

    Lasch, Peter; Lewis, E. Neil; Kidder, Linda H.; Naumann, Dieter

    2000-03-01

    FT-IR microspectrometry, particularly in combination with digital imaging techniques shows great promise for in-vivo and ex-vivo medical diagnosis. The statement is based on the knowledge that this method delivers information of the chemical structure and composition of a sample and the fact that any disease is linked to changes in the molecular and structural composition of cells and tissues. Typically, these changes are highly specific for a given tissue structure and are therefore potentially detectable by FT-IR microspectrometry. In this paper we present several approaches for the representation of mid-infrared microspectroscopic data acquired with high spatial resolution by the use of a MCT focal plane array detector. The applicability of image reassembling methodologies like functional group analysis, image reconstruction based on factor analysis and artificial neural network analysis to the IR data is discussed.

  15. Classification of FTIR cancer data using wavelets and BPNN

    NASA Astrophysics Data System (ADS)

    Cheng, Cungui; Tian, Yumei; Zhang, Changjiang

    2007-11-01

    In this paper, a feature extracting method based on wavelets for horizontal attenuated total reflectance Fourier transform infrared spectroscopy (HATR-FTIR) cancer data analysis and classification using artificial neural network trained with back-propagation algorithm is presented. 168 Spectra were collected from 84 pairs of fresh normal and abnormal lung tissue's samples. After preprocessing, 12 features were extracted with continuous wavelet analysis. Based on BPNN classification, all spectra were classified into two categories : normal or abnormal. The accuracy of identifying normal, early carcinoma, and advanced carcinoma were 100%, 90% and 100% respectively. This result indicated that FTIR with continuous wavelet transform (CWT) and the back-propagation neural network (BPNN) could effectively and easily diagnose lung cancer in its early stages.

  16. Synchrotron-based FTIR spectromicroscopy: Cytotoxicity and heating considerations

    SciTech Connect

    Holman, Hoi-Ying N.; Martin, Michael C.; McKinney, Wayne R.

    2002-12-13

    Synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectromicroscopy is a newly emerging bioanalytical and imaging tool. This unique technique provides mid-infrared (IR) spectra, hence chemical information, with high signal-to-noise at spatial resolutions as fine as 3 to 10 microns. Thus it enables researchers to locate, identify, and track specific chemical events within an individual living mammalian cell. Mid-IR photons are too low in energy (0.05 - 0.5 eV) to either break bonds or to cause ionization. In this review, we show that the synchrotron IR beam has no detectable effects on the short- and long-term viability, reproductive integrity, cell-cycle progression, and mitochondrial metabolism in living human cells, and produces only minimal sample heating (< 0.5 degrees C). These studies have established an important foundation for SR-FTIR spectromicroscopy in biological and biomedical research.

  17. Site-directed isotope labelling and FTIR spectroscopy of bacteriorhodopsin.

    PubMed

    Sonar, S; Lee, C P; Coleman, M; Patel, N; Liu, X; Marti, T; Khorana, H G; RajBhandary, U L; Rothschild, K J

    1994-08-01

    Insight into integral membrane proteins function is presently limited by the difficulty of producing three-dimensional crystals. In addition, X-ray structures of proteins normally do not provide information about the protonation state and structural changes of individual residues. We report here the first use of site-directed isotope labelling and Fourier transform infrared (FTIR) difference spectroscopy to detect structural changes at the level of single residues in an integral membrane protein. Two site-directed isotope labeled (SDIL) tyrosine analogues of bacteriorhodopsin were produced which exhibit normal activity. FTIR spectroscopy shows that out of 11 tyrosines, only Tyr 185 is structurally active during the early photocycle and may be part of a proton wire. PMID:7664078

  18. FT-IR microscopy imaging on oral cavity tumours, II

    NASA Astrophysics Data System (ADS)

    Conti, C.; Giorgini, E.; Pieramici, T.; Rubini, C.; Tosi, G.

    2005-06-01

    Changes in the biochemistry of oral cavity tissues have been studied by FT-IR microscopy. Various aspects of squamous cell carcinomas of cheek mucosa, of tongue, of gingiva, and of the floor of the mouth have been analyzed through FT-IR imaging with the aim to relate spectral patterns with histopathological results. In particular, changes in frequency and intensity of proteins, connective and nucleic acids vibrational modes as well as the visualization of biochemical single wavenumber or band ratio images allowed a quali- and quantitative evaluation of the changes in the proliferating activity from displastic to neoplastic states. 'Supervised' and 'unsupervised' procedures of data handling afforded a satisfactory degree of accordance between spectroscopic and histological findings.

  19. TATP stand-off detection with open path: FTIR techniques

    NASA Astrophysics Data System (ADS)

    Fischer, C.; Pohl, T.; Weber, K.; Vogel, A.; van Haren, G.; Schweikert, W.

    2012-10-01

    TATP is a very easy to synthesize [9], sensitive, high explosive [10] and high volatile explosive [1, 3, 7] with great absorption in the IR Spectra [4, 5, 6]. In this project we detect TATP gas traces with open path FTIR - techniques. The first project phase was to construct and build a heatable multi-reflection cell with adjustable optical path length and a heatable intake to evaporate solid TATP samples. In this cell reference TATP - spectra were collected under controlled conditions with a Bruker FTIR system (Typ OPAG 33). The next step was to find out how the TATP gas will be diluted in the ambient air and validate some physical properties which are described inconsistently in literature e.g. evaporation rates. We constructed a special double - T shaped chamber with stabile air conditions. In this chamber the dispersion kinetics of the TATP vapour could be tested. It turned out that the TATP vapours has the tendency to drop down. Therefore the highest TATP - concentrations were measured below the TATP sample. During the investigation for this study it turned out, that some materials scrub the TATP- vapour out of the air, e.g. Metals, fabric, leather. In the second phase of the project successful open path FTIR- measurements were taken in ambient air and will be continued with different system configurations of the OPAG 33 to lower the detection limits. Also successful measurements were taken in indoor ambient air with a Hyper spectral camera (passive FTIR with array sensor) to detect TATP in solid and gaseous phase. This technique allows detecting TATP and identifying the TATP source. The poster shows some selected results of the continued research.

  20. Carbonate fuel cell matrix

    DOEpatents

    Farooque, M.; Yuh, C.Y.

    1996-12-03

    A carbonate fuel cell matrix is described comprising support particles and crack attenuator particles which are made platelet in shape to increase the resistance of the matrix to through cracking. Also disclosed is a matrix having porous crack attenuator particles and a matrix whose crack attenuator particles have a thermal coefficient of expansion which is significantly different from that of the support particles, and a method of making platelet-shaped crack attenuator particles. 8 figs.

  1. Carbonate fuel cell matrix

    DOEpatents

    Farooque, Mohammad; Yuh, Chao-Yi

    1996-01-01

    A carbonate fuel cell matrix comprising support particles and crack attenuator particles which are made platelet in shape to increase the resistance of the matrix to through cracking. Also disclosed is a matrix having porous crack attenuator particles and a matrix whose crack attenuator particles have a thermal coefficient of expansion which is significantly different from that of the support particles, and a method of making platelet-shaped crack attenuator particles.

  2. Monitoring leaking gases by OP-FTIR remote sensing.

    PubMed

    Li, Yan; Wang, Jun-De; Huang, Zhong-Hua; Xu, Hou-Qian; Zhou, Xue-Tie

    2002-09-01

    Measurement of leaking gases using Open Path Fourier Transform Infrared (OP-FTIR) spectroscopy was carried out in this study to acquire Path Integrated Concentration (PIC) data. Three hazardous Volatile Organic Compounds (VOCs) namely methylene chloride, chloroform and acetone were analyzed. For the two-component leaking source, the PIC data were easily obtained through ordinary calculation and compared to those obtained from Artificial Neural Network (ANN). When the leaking source was composed of three VOCs whose characteristic peaks interfere with each other, it was necessary to do spectral correction for multicomponent analysis with ANN. The Absorbance-Wavenumber-Time 3D spectra of the leaking sources and concentration variations with the leaking time were plotted. The results showed that OP-FTIR is a good quantitative analytical method for indoor or field air pollution. Further more, the remote sensing OP-FTIR system could be utilized to continuously monitor many more toxic gases and work as an alert system for the real time monitoring of hazardous gases beyond normal working conditions of various kinds of areas, such as living or industrial areas. PMID:12369638

  3. Phenotypic Expression in Wheat Revealed Using FT-IR Microspectroscopy

    SciTech Connect

    Brewer, L.; Wetzel, D

    2009-01-01

    Wheat selected for cultivation through the centuries has a glume that is 'soft' instead of 'tough' as naturally occurring. In production, this is desirable because it enables mechanical threshing with efficient separation of kernel from the head of each stalk without damaging the kernel. FT-IR microspectroscopy provides chemically based, objective assessment of genetic expression by measuring the extent of genetic expression. In the Microbeam Molecular Spectroscopy Laboratory, Manhattan, KS, an imaging FT-IR microspectrometer with a detector array focused on the image plane was used to obtain spectral data from dissected glume specimens of nine tough and eleven soft wheat cultivars in a rectangular mapping pattern. With cellulose as the substrate, the extent of lignification is measurable from the ratio of the lignin (1508 cm{sup -1}) baseline adjusted band area to the representative cellulosic (1370 cm{sup -1}) band area. A distinction between soft and tough glumes is obtained in numerical terms. Using a band ratio minimizes variation due to thickness differences. While analyzing mapped sections of glume, care is taken to avoid tabulation of spectral data from vascular bundles. Inclusion of these data would to avoid tabulation of spectral data from vascular bundles. Inclusion of these data would bias the analysis toward the composition of highly lignified vascular bundles. Spatially resolved focal plane array FT-IR microspectroscopy reveals the extent of glume lignification that is coincident with the toughness trait. This enables breeders to rank the degree of lignin expression and discriminate between soft and tough breeding results.

  4. Characterization and identification of microorganisms by FT-IR microspectrometry

    NASA Astrophysics Data System (ADS)

    Ngo-Thi, N. A.; Kirschner, C.; Naumann, D.

    2003-12-01

    We report on a novel FT-IR approach for microbial characterization/identification based on a light microscope coupled to an infrared spectrometer which offers the possibility to acquire IR-spectra of microcolonies containing only few hundred cells. Microcolony samples suitable for FT-IR microspectroscopic measurements were obtained by a replica technique with a stamping device that transfers spatially accurate cells of microcolonies growing on solid culture plates to a special, IR-transparent or reflecting stamping plate. High quality spectra could be recorded either by applying the transmission/absorbance or the reflectance/absorbance mode of the infrared microscope. Signal to noise ratios higher than 1000 were obtained for microcolonies as small as 40 μm in diameter. Reproducibility levels were established that allowed species and strain identification. The differentiation and classification capacity of the FT-IR microscopic technique was tested for different selected microorganisms. Cluster and factor analysis methods were used to evaluate the complex spectral data. Excellent discrimination between bacteria and yeasts, and at the same time Gram-negative and Gram-positive bacterial strains was obtained. Twenty-two selected strains of different species within the genus Staphylococcus were repetitively measured and could be grouped into correct species cluster. Moreover, the results indicated that the method allows also identifications at the subspecies level. Additionally, the new approach allowed spectral mapping analysis of single colonies which provided spatially resolved characterization of growth heterogeneity within complex microbial populations such as colonies.

  5. Photoacoustic FTIR spectroscopic study of undisturbed nacre from red abalone

    NASA Astrophysics Data System (ADS)

    Verma, Devendra; Katti, Kalpana; Katti, Dinesh

    2006-07-01

    In this work, photoacoustic Fourier transform infrared (PA-FTIR) spectroscopy has been utilized to study interfacial interactions of undisturbed nacre and nacre powder from red abalone shell. The spectra of both undisturbed nacre and nacre powder showed characteristic bands of aragonite and proteins. Although nacre powder and undisturbed nacre are chemically identical, PA-FTIR spectrum of undisturbed nacre is found to be significantly different from that of nacre powder. A broad and strong band is observed at around 1485 cm -1 in nacre powder. The intensity of this band is notably reduced in undisturbed nacre. This result is explained on the basis of interfacial interactions between aragonite platelets and acidic proteins. It is also observed that band at around 1788 cm -1 originates from three overlapping bands 1797, 1787 and 1778 cm -1. The band at around 1787 cm -1 is assigned to C dbnd O stretching of carboxylate groups of acidic proteins. The other two bands at 1797 and 1778 cm -1, originate from aragonite and have been assigned to combination bands, ν 3 + ν 4a and ν 3 + ν 4b, respectively. For the study of stratification in undisturbed nacre, PA-FTIR spectra have been collected in step scan mode. The variation in spectra with depth can be attributed to changes in conformation of proteins as well as interfacial interactions.

  6. Matrix differentiation formulas

    NASA Technical Reports Server (NTRS)

    Usikov, D. A.; Tkhabisimov, D. K.

    1983-01-01

    A compact differentiation technique (without using indexes) is developed for scalar functions that depend on complex matrix arguments which are combined by operations of complex conjugation, transposition, addition, multiplication, matrix inversion and taking the direct product. The differentiation apparatus is developed in order to simplify the solution of extremum problems of scalar functions of matrix arguments.

  7. Matrix with Prescribed Eigenvectors

    ERIC Educational Resources Information Center

    Ahmad, Faiz

    2011-01-01

    It is a routine matter for undergraduates to find eigenvalues and eigenvectors of a given matrix. But the converse problem of finding a matrix with prescribed eigenvalues and eigenvectors is rarely discussed in elementary texts on linear algebra. This problem is related to the "spectral" decomposition of a matrix and has important technical…

  8. Ubiquitination of specific mitochondrial matrix proteins.

    PubMed

    Lehmann, Gilad; Ziv, Tamar; Braten, Ori; Admon, Arie; Udasin, Ronald G; Ciechanover, Aaron

    2016-06-17

    Several protein quality control systems in bacteria and/or mitochondrial matrix from lower eukaryotes are absent in higher eukaryotes. These are transfer-messenger RNA (tmRNA), The N-end rule ATP-dependent protease ClpAP, and two more ATP-dependent proteases, HslUV and ClpXP (in yeast). The lost proteases resemble the 26S proteasome and the role of tmRNA and the N-end rule in eukaryotic cytosol is performed by the ubiquitin proteasome system (UPS). Therefore, we hypothesized that the UPS might have substituted these systems - at least partially - in the mitochondrial matrix of higher eukaryotes. Using three independent experimental approaches, we demonstrated the presence of ubiquitinated proteins in the matrix of isolated yeast mitochondria. First, we show that isolated mitochondria contain ubiquitin (Ub) conjugates, which remained intact after trypsin digestion. Second, we demonstrate that the mitochondrial soluble fraction contains Ub-conjugates, several of which were identified by mass spectrometry and are localized to the matrix. Third, using immunoaffinity enrichment by specific antibodies recognizing digested ubiquitinated peptides, we identified a group of Ub-modified matrix proteins. The modification was further substantiated by separation on SDS-PAGE and immunoblots. Last, we attempted to identify the ubiquitin ligase(s) involved, and identified Dma1p as a trypsin-resistant protein in our mitochondrial preparations. Taken together, these data suggest a yet undefined role for the UPS in regulation of the mitochondrial matrix proteins. PMID:27157140

  9. Fourier Transform Infrared Spectroscopy: Part II. Advantages of FT-IR.

    ERIC Educational Resources Information Center

    Perkins, W. D.

    1987-01-01

    This is Part II in a series on Fourier transform infrared spectroscopy (FT-IR). Described are various advantages of FT-IR spectroscopy including energy advantages, wavenumber accuracy, constant resolution, polarization effects, and stepping at grating changes. (RH)

  10. Nanocrystal doped matrixes

    DOEpatents

    Parce, J. Wallace; Bernatis, Paul; Dubrow, Robert; Freeman, William P.; Gamoras, Joel; Kan, Shihai; Meisel, Andreas; Qian, Baixin; Whiteford, Jeffery A.; Ziebarth, Jonathan

    2010-01-12

    Matrixes doped with semiconductor nanocrystals are provided. In certain embodiments, the semiconductor nanocrystals have a size and composition such that they absorb or emit light at particular wavelengths. The nanocrystals can comprise ligands that allow for mixing with various matrix materials, including polymers, such that a minimal portion of light is scattered by the matrixes. The matrixes of the present invention can also be utilized in refractive index matching applications. In other embodiments, semiconductor nanocrystals are embedded within matrixes to form a nanocrystal density gradient, thereby creating an effective refractive index gradient. The matrixes of the present invention can also be used as filters and antireflective coatings on optical devices and as down-converting layers. Processes for producing matrixes comprising semiconductor nanocrystals are also provided. Nanostructures having high quantum efficiency, small size, and/or a narrow size distribution are also described, as are methods of producing indium phosphide nanostructures and core-shell nanostructures with Group II-VI shells.

  11. [The effect of Tween-80 on the differentiation of Trichophyton mentagrophytes and Trichophyton rubrum strains with FT-IR spectroscopy].

    PubMed

    Ergın, Çagri; İlkit, Macit; Gök, Yaşar; Çon, Ahmet Hilmi; Özel, Mustafa Zafer; Kabay, Nilgün; Döğen, Aylin; Baygu, Yasemin

    2014-07-01

    was sufficient to enable differentiation of T.mentagrophytes complex from T.rubrum complex by FT-IR spectroscopy. This effect might be attributed to the possible transfer of lipid compounds from culture to cell structure during growth. Further studies with the use of large number of reference strains and clinical isolates exposed to different environmental factors, such as antifungal agents and inorganic ions, are needed to support these data indicating favorable effect of Tween-80 on the differentiation of T.mentagrophytes and T.rubrum complexes by FT-IR spectroscopy. PMID:25052111

  12. Matrix-isolation infrared studies of 1:1 molecular complexes containing chloroform (CHCl3) and Lewis bases: Seamless transition from blue-shifted to red-shifted hydrogen bonds

    NASA Astrophysics Data System (ADS)

    Ito, Fumiyuki

    2012-07-01

    The infrared spectra of molecular complexes containing chloroform (CHCl3) and Lewis bases (N2, CO, H2O, and CH3CN) have been observed in an Ar matrix, and vibrational peaks for the 1:1 complexes have been assigned. The C-H stretching band of chloroform in the complexes showed a seamless transition from a blue shift (for N2 and CO) to a red shift (H2O and CH3CN), in accord with the proton affinity of the base molecules. Density functional calculations predicted that the C-H. .(σ-type lone pair) isomer is the most stable, which is consistent with the observed vibrational peak shift upon complex formation. The underlying mechanisms of the C-H hydrogen bond were explored using the topological properties of the electronic charge density and natural orbital analyses.

  13. FTIR instrumentation to monitor vapors from Shuttle tile waterproofing materials

    NASA Astrophysics Data System (ADS)

    Mattson, C. B.; Schwindt, C. J.

    1995-11-01

    The Space Shuttle Thermal Protection System (TPS) tiles and blankets are waterproofed using DimethylEthoxySilane (DMEX) in the Orbiter Processing Facilities (OPF). DMES has a Threshold Limit Value (TLV) for exposure of personnel to vapor concentration in air of 0.5 ppm. The OPF high bay cannot be opened for normal work after a waterproofing operation until the DMES concentration is verified by measurement to be below the TLV. On several occasions the high bay has been kept closed for up to 8 hours following waterproofing operations due to high DMES measurements. In addition, the Miran 203 and Miran 1 BX infrared analyzers calibrated at different wavelengths gave different readings under the same conditions. There was reason to believe that some of the high DMES concentration readings were caused by interference form water and ethanol vapors. The Toxic Vapor Detection Laboratory (TVDL) was asked to test the existing DMES instruments and identify the best qualified instrument. In addition the TVDL was requested to develop instrumentation to ensure the OPF high bay could be opened safely as soon as possible after a waterproofing operation. A Fourier Transform Infrared (FTIR) spectrophotometer instrument developed for an earlier project was reprogrammed to measure DMES vapor along with ethanol, water, and several common solvent vapors. The FTIR was then used to perform a series of laboratory and field tests to evaluate the performance of the single wavelength IR instruments in use. The results demonstrated that the single wavelength IR instruments did respond to ethanol and water vapors, more or less depending on the analytical IR wavelength selected. The FTIR was able to separate the responses to DMES, water and ethanol, and give consistent readings for the DMES vapor concentration. The FTIR was then deployed to the OPF to monitor real waterproofing operations. The FTIR was also used to measure the time for DMES to evaporate from TPS tile under a range of humidity

  14. FTIR instrumentation to monitor vapors from Shuttle tile waterproofing materials

    NASA Technical Reports Server (NTRS)

    Mattson, C. B.; Schwindt, C. J.

    1995-01-01

    The Space Shuttle Thermal Protection System (TPS) tiles and blankets are waterproofed using DimethylEthoxySilane (DMEX) in the Orbiter Processing Facilities (OPF). DMES has a Threshold Limit Value (TLV) for exposure of personnel to vapor concentration in air of 0.5 ppm. The OPF high bay cannot be opened for normal work after a waterproofing operation until the DMES concentration is verified by measurement to be below the TLV. On several occasions the high bay has been kept closed for up to 8 hours following waterproofing operations due to high DMES measurements. In addition, the Miran 203 and Miran 1 BX infrared analyzers calibrated at different wavelengths gave different readings under the same conditions. There was reason to believe that some of the high DMES concentration readings were caused by interference form water and ethanol vapors. The Toxic Vapor Detection Laboratory (TVDL) was asked to test the existing DMES instruments and identify the best qualified instrument. In addition the TVDL was requested to develop instrumentation to ensure the OPF high bay could be opened safely as soon as possible after a waterproofing operation. A Fourier Transform Infrared (FTIR) spectrophotometer instrument developed for an earlier project was reprogrammed to measure DMES vapor along with ethanol, water, and several common solvent vapors. The FTIR was then used to perform a series of laboratory and field tests to evaluate the performance of the single wavelength IR instruments in use. The results demonstrated that the single wavelength IR instruments did respond to ethanol and water vapors, more or less depending on the analytical IR wavelength selected. The FTIR was able to separate the responses to DMES, water and ethanol, and give consistent readings for the DMES vapor concentration. The FTIR was then deployed to the OPF to monitor real waterproofing operations. The FTIR was also used to measure the time for DMES to evaporate from TPS tile under a range of humidity

  15. An in situ FTIR step-scan photoacoustic investigation of kerogen and minerals in oil shale

    NASA Astrophysics Data System (ADS)

    Alstadt, Kristin N.; Katti, Dinesh R.; Katti, Kalpana S.

    2012-04-01

    Step-scan photoacoustic infrared spectroscopy experiments were performed on Green River oil shale samples obtained from the Piceance Basin located in Colorado, USA. We have investigated the molecular nature of light and dark colored areas of the oil shale core using FTIR photoacoustic step-scan spectroscopy. This technique provided us with the means to analyze the oil shale in its original in situ form with the kerogen-mineral interactions intact. All vibrational bands characteristic of kerogen were found in the dark and light colored oil shale samples confirming that kerogen is present throughout the depth of the core. Depth profiling experiments indicated that there are changes between layers in the oil shale molecular structure at a length scale of micron. Comparisons of spectra from the light and dark colored oil shale core samples suggest that the light colored regions have high kerogen content, with spectra similar to that from isolated kerogen, whereas, the dark colored areas contain more mineral components which include clay minerals, dolomite, calcite, and pyrite. The mineral components of the oil shale are important in understanding how the kerogen is "trapped" in the oil shale. Comparing in situ kerogen spectra with spectra from isolated kerogen indicate significant band shifts suggesting important nonbonded molecular interactions between the kerogen and minerals.

  16. Differentiation of Leishmania species by FT-IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Aguiar, Josafá C.; Mittmann, Josane; Ferreira, Isabelle; Ferreira-Strixino, Juliana; Raniero, Leandro

    2015-05-01

    Leishmaniasis is a parasitic infectious disease caused by protozoa that belong to the genus Leishmania. It is transmitted by the bite of an infected female Sand fly. The disease is endemic in 88 countries Desjeux (2001) [1] (16 developed countries and 72 developing countries) on four continents. In Brazil, epidemiological data show the disease is present in all Brazilian regions, with the highest incidences in the North and Northeast. There are several methods used to diagnose leishmaniasis, but these procedures have many limitations, are time consuming, have low sensitivity, and are expensive. In this context, Fourier Transform Infrared Spectroscopy (FT-IR) analysis has the potential to provide rapid results and may be adapted for a clinical test with high sensitivity and specificity. In this work, FT-IR was used as a tool to investigate the promastigotes of Leishmaniaamazonensis, Leishmaniachagasi, and Leishmaniamajor species. The spectra were analyzed by cluster analysis and deconvolution procedure base on spectra second derivatives. Results: cluster analysis found four specific regions that are able to identify the Leishmania species. The dendrogram representation clearly indicates the heterogeneity among Leishmania species. The band deconvolution done by the curve fitting in these regions quantitatively differentiated the polysaccharides, amide III, phospholipids, proteins, and nucleic acids. L. chagasi and L. major showed a greater biochemistry similarity and have three bands that were not registered in L. amazonensis. The L. amazonensis presented three specific bands that were not recorded in the other two species. It is evident that the FT-IR method is an indispensable tool to discriminate these parasites. The high sensitivity and specificity of this technique opens up the possibilities for further studies about characterization of other microorganisms.

  17. Discrepancies in degree of conversion measurements by FTIR.

    PubMed

    Collares, Fabrício Mezzomo; Portella, Fernando Freitas; Leitune, Vicente Castelo Branco; Samuel, Susana Maria Werner

    2014-01-01

    The purpose of this study was to evaluate the influence of the internal standard peak on the measured degree of conversion (DC) for methacrylate-based resins analyzed by Fourier-transform infrared spectroscopy (FTIR). The influence of different baseline measurement methods was also determined. Different blends were prepared, mixing BisGMA/BisEMA and BisGMA/TEGDMA at proportions of 0% to 100%, in weight. Camphoroquinone and ethyl-4-dimethylamino-benzoate were used to permit the light activation of blends. Degree of conversion was evaluated using FTIR equipped with an attenuated total reflectance (ATR) device. Samples were dispensed onto ATR crystal and light activated for 40 s. The DC was calculated by relating the height of the peak 1637 cm-1 to the intensity of different internal standard peaks (1715, 1608, or 1582 cm-1), measured using two different baseline methods, before and after polymerization. Data were compared by ANOVA at 5% significance. The relationship between DC and monomer ratio was obtained by regression analysis. Double-bond conversion ranged from 32.75% to 78.50% for BisGMA/BisEMA blends, and from 32.75% to 76.22% for BisGMA/TEGDMA blends. For the BisGMA/BisEMA blends, the DC showed a linear association with the composition of the comonomer blends, independent of the internal standard peak and baseline method used. In contrast, the trends in DC for BisGMA/TEGDMA blends were different for each method of measurement. The internal standard peaks and measurement baseline should be taken into account when using FTIR to calculate the DC of methacrylate-based resins, especially comonomer blends containing a high degree of monomers that lack aromatic rings. PMID:24402058

  18. Retrieval of ammonia from ground-based FTIR solar spectra

    NASA Astrophysics Data System (ADS)

    Dammers, E.; Vigouroux, C.; Palm, M.; Mahieu, E.; Warneke, T.; Smale, D.; Langerock, B.; Franco, B.; Van Damme, M.; Schaap, M.; Notholt, J.; Erisman, J. W.

    2015-11-01

    We present a retrieval method for ammonia (NH3) total columns from ground-based Fourier transform infrared (FTIR) observations. Observations from Bremen (53.10° N, 8.85° E), Lauder (45.04° S, 169.68° E), Réunion (20.9° S, 55.50° E) and Jungfraujoch (46.55° N, 7.98° E) were used to illustrate the capabilities of the method. NH3 mean total columns ranging 3 orders of magnitude were obtained, with higher values at Bremen (mean of 13.47 × 1015 molecules cm-2) and lower values at Jungfraujoch (mean of 0.18 × 1015 molecules cm-2). In conditions with high surface concentrations of ammonia, as in Bremen, it is possible to retrieve information on the vertical gradient, as two layers can be distinguished. The retrieval there is most sensitive to ammonia in the planetary boundary layer, where the trace gas concentration is highest. For conditions with low concentrations, only the total column can be retrieved. Combining the systematic and random errors we have a mean total error of 26 % for all spectra measured at Bremen (number of spectra (N) = 554), 30 % for all spectra from Lauder (N = 2412), 25 % for spectra from Réunion (N = 1262) and 34 % for spectra measured at Jungfraujoch (N = 2702). The error is dominated by the systematic uncertainties in the spectroscopy parameters. Station-specific seasonal cycles were found to be consistent with known seasonal cycles of the dominant ammonia sources in the station surroundings. The developed retrieval methodology from FTIR instruments provides a new way of obtaining highly time-resolved measurements of ammonia burdens. FTIR-NH3 observations will be useful for understanding the dynamics of ammonia concentrations in the atmosphere and for satellite and model validation. It will also provide additional information to constrain the global ammonia budget.

  19. Experimental simulation of organic matter alteration in carbonaceous chondrites under an in situ micro FTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Kebukawa, Y.; Nakashima, S.; Saiki, K.; Zolensky, M. E.

    2007-12-01

    Carbonaceous chondrites contain organic matter up to a few weight percents, most of which consists of kerogen- like macromolecular material. Chondritic organic matter preserves signatures of various evolutional steps from presolar materials, through aqueous alteration and thermal metamorphism in the parent asteroid up to delivery to the Earth. The organic-mineral interactions during these processes are little known. We report here on the experimental simulation of organic matter alteration on carbonaceous chondrite parent body under micro FTIR spectroscopy with a heating stage. Leonardite humic acid (IHSS standard humic acid) and synthetic saponite or natural antigorite were used as the macromolecular organic matter and the matrix mineral. These powdered samples were dispersed by MilliQ water then dropped on a CaF2 plate and dried. They were heated in the heating stage from room temperature to 600 °C with a heating rate of 10 °C/min in air, Ar gas, and H2+CO2 gas mixture (mixing ratio 1:1). H2+CO2 gas mixture enables controls of not only oxygen fugacity but also water vapor fugacity, and aqueous processing on chondrite parent bodies can be partly simulated. IR spectra were collected at every 20 °C under the micro FTIR spectroscopy. Aliphatic C-H increased from room temperature to approximately 250 °C then decreased. Aromatic C-H increased from room temperature to around 400-450 °C then decreased. These aliphatic C-H decrease and aromatic C-H increase are faster in air than in Ar or H2+CO2. These CH changes of leonardite humic acid are slower with the presence of saponite. These results indicate that organic matter transformation might be prevented by the clay mineral (saponite). Some carbonaceous chondrite samples mixed with the organic material (leonardite humic acid) will also be investigated by the same way. These results will elucidate interactions of chondritic macromolecular organic matter with matrix minerals during parent body processes.

  20. FTIR spectrometer with solid-state drive system

    DOEpatents

    Rajic, Slobodan; Seals, Roland D.; Egert, Charles M.

    1999-01-01

    An FTIR spectrometer (10) and method using a solid-state drive system with thermally responsive members (27) that are subject to expansion upon heating and to contraction upon cooling. Such members (27) are assembled in the device (10) so as to move an angled, reflective surface (22) a small distance. The sample light beam (13) is received at a detector (24) along with a reference light beam (13) and there it is combined into a resulting signal. This allows the "interference" between the two beams to occur for spectral analysis by a processor (29).

  1. Control of separation and quantitative analysis by GC-FTIR

    NASA Astrophysics Data System (ADS)

    Semmoud, A.; Huvenne, Jean P.; Legrand, P.

    1992-03-01

    Software for 3-D representations of the 'Absorbance-Wavenumber-Retention time' is used to control the quality of the GC separation. Spectral information given by the FTIR detection allows the user to be sure that a chromatographic peak is 'pure.' The analysis of peppermint essential oil is presented as an example. This assurance is absolutely required for quantitative applications. In these conditions, we have worked out a quantitative analysis of caffeine. Correlation coefficients between integrated absorbance measurements and concentration of caffeine are discussed at two steps of the data treatment.

  2. Spaceborne Hybrid-FPGA System for Processing FTIR Data

    NASA Technical Reports Server (NTRS)

    Bekker, Dmitriy; Blavier, Jean-Francois L.; Pingree, Paula J.; Lukowiak, Marcin; Shaaban, Muhammad

    2008-01-01

    Progress has been made in a continuing effort to develop a spaceborne computer system for processing readout data from a Fourier-transform infrared (FTIR) spectrometer to reduce the volume of data transmitted to Earth. The approach followed in this effort, oriented toward reducing design time and reducing the size and weight of the spectrometer electronics, has been to exploit the versatility of recently developed hybrid field-programmable gate arrays (FPGAs) to run diverse software on embedded processors while also taking advantage of the reconfigurable hardware resources of the FPGAs.

  3. TG-FTIR characterization of flame retardant polyurethane foams materials

    NASA Astrophysics Data System (ADS)

    Liu, W.; Tang, Y.; Li, F.; Ge, X. G.; Zhang, Z. J.

    2016-07-01

    Dimethyl methylphosphonate (DMMP) and trichloroethyl phosphtate (TCEP) have been used to enhance the flame retardancy of polyurethane foams materials (PUF). Flame retardancy and thermal degradation of PUF samples have been investigated by the LOI tests and thermal analysis. The results indicate that the excellent flame retardancy can be achieved due to the presence of the flame retardant system containing DMMP and TCEP. TG-FTIR reveals that the addition of DMMP/TCEP can not only improve the thermal stability of PUF samples but can also affect the gaseous phase at high temperature.

  4. FTIR study of horseradish peroxidase in reverse micelles.

    PubMed

    Chen, J; Xia, C; Niu, J; Li, S

    2001-04-20

    Fourier transform infrared (FTIR) method was used to study the secondary structures of horseradish peroxidase (HRP) in aqueous solution and in reverse micelles for the first time. Results indicated that the structure of HRP in sodium bis(2-ethylhexy)sulfosuccinate (AOT) reverse micelles was close to that in aqueous solution. In cetyltrimethylammonium bromide (CTAB) and sodium dodecylfate (SDS) reverse micelles the position of some bands changed. Results indicated that the secondary structure had a close relationship with the surfactant species of the reverse micelles. Among the three types of reverse micelles, the system of AOT reverse micelles was probably the most beneficial reaction media to HRP. PMID:11302746

  5. An investigation into the photochemistry of, and the electrochemically induced CO-loss from, [(CO)5MC(OMe)Me](M = Cr or W) using low-temperature matrix isolation, picosecond infrared spectroscopy, cyclic voltammetry, and time-dependent density functional theory.

    PubMed

    McMahon, Suzanne; Amirjalayer, Saeed; Buma, Wybren J; Halpin, Yvonne; Long, Conor; Rooney, A Denise; Woutersen, Sander; Pryce, Mary T

    2015-09-21

    The photophysics and photochemistry of [(CO)5MC(OMe)Me] (M = Cr or W) were investigated using picosecond time-resolved infrared spectroscopy (M = Cr or W), low-temperature matrix isolation techniques (M = Cr), and time-dependent density functional calculations (M = Cr or W). These studies provide unambiguous evidence for the photochemical formation of a long-lived, 18-electron metallaketene species capable of acting as a synthetically useful intermediate. For the Cr complex, an intermediate metallacyclopropanone singlet excited state was detected on the reaction path to the metallaketene species. This metallacyclopropanone excited state species has a lifetime of less than 100 ps and a characteristic bridging carbonyl band at 1770 cm(-1). The tungsten ketene species was also detected but in contrast to the chromium system, this forms directly from a low-lying triplet excited state. The electrochemical release of CO showed a greater efficiency for the chromium complex when compared to the tungsten. PMID:26089130

  6. D1(2B2g)→D0(2Au) fluorescence from the matrix-isolated perylene cation following laser excitation into the D5(2B3g) and D2(2B3g) electronic states

    NASA Astrophysics Data System (ADS)

    Chillier, Xavier D. F.; Stone, Bradley M.; Joblin, Christine; Salama, Farid; Allamandola, Louis J.

    2002-04-01

    Fluorescence spectra of the perylene cation, isolated in an argon matrix and pumped by direct laser excitation via the D2(2B3g)←D0(2Au) and D5(2B3g)←D0(2Au) transitions, are presented. Direct excitation into the D5 or D2 states is followed by rapid nonradiative relaxation to D1 that, in turn, relaxes radiatively. Excitation spectroscopy across the D2(2B3g)←D0(2Au) transition near 731 nm shows that site splitting plays little or no role in determining the spectral substructure in the ion spectra. Tentative assignments for ground state vibrational frequencies are made by a comparison of spectral intervals with calculated normal mode frequencies, with the strongest IR bands leading to the most intense vibronic bands.

  7. Elastase Deficiency Phenotype of Pseudomonas aeruginosa Canine Otitis Externa Isolates

    PubMed Central

    Petermann, Shana R.; Doetkott, Curt; Rust, Lynn

    2001-01-01

    Pseudomonas aeruginosa veterinary isolates were assayed for elastase and total matrix protease activity. The elastase activity of canine ear isolates was much less than that of strain PAO1 and that of all other veterinary isolates (P < 0.0001). The results indicate that canine ear isolates have a distinct elastase phenotype. PMID:11329471

  8. Biofilm Matrix Proteins

    PubMed Central

    Fong, Jiunn N. C.; Yildiz, Fitnat H.

    2015-01-01

    Proteinaceous components of the biofilm matrix include secreted extracellular proteins, cell surface adhesins and protein subunits of cell appendages such as flagella and pili. Biofilm matrix proteins play diverse roles in biofilm formation and dissolution. They are involved in attaching cells to surfaces, stabilizing the biofilm matrix via interactions with exopolysaccharide and nucleic acid components, developing three-dimensional biofilm architectures, and dissolving biofilm matrix via enzymatic degradation of polysaccharides, proteins, and nucleic acids. In this chapter, we will review functions of matrix proteins in a selected set of microorganisms, studies of the matrix proteomes of Vibrio cholerae and Pseudomonas aeruginosa, and roles of outer membrane vesicles and of nucleoid-binding proteins in biofilm formation. PMID:26104709

  9. Automatic switching matrix

    DOEpatents

    Schlecht, Martin F.; Kassakian, John G.; Caloggero, Anthony J.; Rhodes, Bruce; Otten, David; Rasmussen, Neil

    1982-01-01

    An automatic switching matrix that includes an apertured matrix board containing a matrix of wires that can be interconnected at each aperture. Each aperture has associated therewith a conductive pin which, when fully inserted into the associated aperture, effects electrical connection between the wires within that particular aperture. Means is provided for automatically inserting the pins in a determined pattern and for removing all the pins to permit other interconnecting patterns.

  10. FT-IR method to determine Dill's C parameter for DNQ/novolac resists with e-beam and i-line exposure

    NASA Astrophysics Data System (ADS)

    Fedynyshyn, Theodore H.; Doran, Scott P.; Mack, Chris A.

    1999-06-01

    Typically, the Dill ABC parameters for optical resist are determined by coating a resist on a nonreflecting substrate and then measuring the change in the intensity of transmitted light at the wavelength of interest as a function of incident energy. Resists absorbance may not be selective in isolating and measuring only the photoactive species, and in some cases changes in absorbance can not be directly correlated to changes in the concentration of the photoactive species. FTIR spectroscopy can directly measure changes in the photoactive species by isolating and measuring absorbance peaks unique to the photoactive species by isolating and measuring absorbance peaks unique to the photoactive species. FTIR, employed in reflectance mode, is not constrained to transparent substrates, but can instead be used with silicon wafers or chrome coated quartz plates. The ability to use these substrates, but can instead be used with silicon wafers or chrome coated quartz plates. The ability to use these substrates is important when determining Dill's C parameter under e-beam exposure where the degree of back-scattered electrons is dependent on the underlying substrate, and the use of quartz is prohibited due to charging considerations. Dill's C parameter is determined for a variety of commercial i-line resist under both e-beam and i-line exposure. The ProABC software, a lithography simulator that extracts ABC parameters through a best fit of model to data, is employed to extract Dill's C parameter. This software has been specially modified to allow FTIR absorbance input.

  11. Assessment of nonenzymatic glycation in protein by FTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Otero de Joshi, Virginia; Joshi, Narahari V.; Gil, Herminia; Velasquez, William; Contreras, Silvia; Marquez, Glevis

    1999-04-01

    Detection of nonenzymatic glycated proteins is a very significant feature in diabetes, aging and related diseases, therefore we have carried out an FTIR spectroscopic study for glycated and native proteins such as (gamma) -globulin, human serum albumin. For this purpose, commercially available proteins were glycated by a usual procedure and their FTIR spectra were recorded together with that of the native ones. In order to follow the changes in time, (gamma) -globulin was glycated during 1, 2, 3, 5 and 8 weeks and their spectra were recorded. Direct verification was obtained by examining a model unit where the -NH2 group was attached to glucose. The spectrum shows a strong peak at 3500 cm-1 confirming the observed variation in time dependent spectra. The general features of the spectra are very similar and there was no additional structure or change in the peaks. This is understandable as not all the lysine residues are glycated, only a small fraction. Glucose is attached to the (epsilon) -amino group of lysine to form Amadori products, and therefore, the vibrational modes corresponding to the (epsilon) -NH2 unit of lysine are expected to be altered. This region exactly lies in the Amide I region of protein structure. Careful investigation of this part, indeed, shows a complex structure originated from alternations of -NH2 group. Thus, the present investigation indicates that an optical approach could be a rapid and effective method to identify the nonenzymatic glycation process.

  12. [DSC and FTIR study of adsorbed lysozyme on hydrophobic surface].

    PubMed

    Lei, Zu-meng; Geng, Xin-peng; Dai, Li; Geng, Xin-du

    2008-09-01

    During a process of hen egg white lysozyme adsorption and folding on a moderately hydrophobic surface (PEG-600), the effects of salt((NH4)2SO4) concentrations, surface coverage and denaturant (guanidine hydrochloride, GuHCl) concentrations on thermal stability and the changes in the molecular conformation of adsorbed native and denatured lysozyme without aqueous solution were studied with a combination of differential scanning calorimetry (DSC) with FTIR spectroscopy. The results showed that temperature due to endothermic peaks was reduced and the disturbance increased at higher temperature with the increase in salt concentration and surface coverage of adsorbed protein. beta-Sheet and beta-Turn stucture increased while alpha-Helix structure decreased after the adsorption. The peaks corresponding to both C-C stretching frequency in 1400-1425 cm(-1) and amide I band frequency in 1650-1670 cm(-1) of adsorbed denatured lysozyme can be detected in FTIR spectra while that due to amide I band frequency of adsorbed native lysozyme almost can't be observed. Adsorption resulted in structural loss of adsorbed native lysozyme, whose performance was less stable. PMID:19093560

  13. XRD, LPF and FTIR investigation of Mn-Bi alloy

    NASA Astrophysics Data System (ADS)

    Mishra, Ashutosh; Patil, Harsha; Jain, Garima

    2014-09-01

    High purity MnBi low temperature phase has been prepared and analyzed using X- ray diffraction, Lorentz-Polarization Factor and Fourier transforms infrared measurement. After synthesis of samples structural characterization has done on samples by X-ray diffraction, which shows that after making the bulk sample is in no single phase MnBi has been prepared by sintering Mn and Bi powder. The X-ray diffraction measurements were carried out using Bruker D8 Advance X-ray diffractometer. The X-rays were produced using a sealed tube and the wavelength of x-ray was 0.154nm (Cu K-alpha).and x-rays were detected using a fast counting detector based on Silicon strip technology (Bruker LynxEye detector). By Lorentz- Polarization Factor is affecting the relative intensity of diffraction lines on a powder form. The infrared absorption spectra of the alloys and intermetallic compound were measured at room temperature, in the wave number range 4000 to 400 cm-1 by a computerized spectrometer type Jasco FTIR-300 (JAPAN) using the KBr pellet technique. And by FTIR which shows absorption peaks of MnBi alloys.

  14. FTIR studies of low temperature sulfuric acid aerosols

    SciTech Connect

    Anthony, S.E.; Tisdale, R.T.; Disselkamp, R.S.

    1995-05-01

    Fourier transform infrared (FTIR) spectroscopy was used to study low temperature sulfuric acid aerosols representative of global stratospheric sulfate aerosols (SSAs). Sub-micrometer sized sulfuric acid (H{sub 2}SO{sub 4}) particles were generated using a constant output atomizer source. The particles were then exposed to water vapor before being injected into a low temperature cell. Multipass transmission FTIR spectroscopy was used to determine the phase and composition of the aerosols as a function of time for periods of up to 5 hours. Binary H{sub 2}SO{sub 4}/H{sub 2}O aerosols with compositions from 35 to 95 wt % H{sub 2}SO{sub 4} remained liquid for over 3 hours at temperatures ranging from 189-240 K. These results suggest that it is very difficult to freeze SSAs via homogeneous nucleation. Attempts to form aerosols more dilute than 35 wt % H{sub 2}SO{sub 4} resulted in ice formation. 18 refs., 7 figs.

  15. [Discrimination of bamboo using FTIR spectroscopy and statistical analysis].

    PubMed

    Li, Lun; Liu, Gang; Zhang, Chuan-Yun; Ou, Quan-Hong; Zhang, Li; Zhao, Xing-Xiang

    2013-12-01

    Fourier transform infrared (FTIR) spectroscopy combined with principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to identify and classify bamboo leaves. FTIR spectra of fifty-four bamboo leaf samples belonging to six species were obtained. The results showed that the infrared spectra of bamboo leaves were similar, and mainly composed of the bands of polysaccharides, protein and lipids. The original spectra exhibit minor differences in the region of 1800-700cm-1. The second derivative spectra show apparent differences in the same region. Principal component analysis and hierarchical cluster analysis were performed on the second derivative infrared spectra in the range from 1800 to 700 cm-1. The leaf samples were separated into 6 groups with accuracy of 98% with the first three principal components, and with 100% accuracy according to the third and fourth principal components. Hierarchical cluster analysis can correctly cluster the bamboo leaf samples. It is proved that Fourier transform infrared spectroscopy combined with PCA and HCA could be used to discriminate bamboo at species level with only a tiny leaf sample. PMID:24611374

  16. Analysis of breast tissue calcifications using FTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Baker, Rebecca N.; Rogers, Keith D.; Shepherd, Neil; Stone, Nicholas

    2007-07-01

    Microalcifications can be found in both benign and malignant breast lesions and their composition can indicate the disease state. Type I microcalcifications are composed of calcium oxalate dihydrate (COD) and are associated mainly with benign tissue, whereas hydroxyapatite (HAP) can be present in both tissue types. As current practices such as mammography and histopathology examine the morphology of the specimen, they can not reliably distinguish between the two types of calcification, which frequently are the only mammographic features that indicate the presence of a cancerous lesion. Analysis of tissue by Fourier transform infrared microspectroscopy (FTIR) allows biochemical information to be achieved from the sample. Spectral maps have been carried out on paraffinized sections of breast tissue from 9 patients of different pathology types containing calcification. The chemical composition of the calcifications and surrounding tissue has been analysed and correlated with tissue pathology. This preliminary study has demonstrated the ability to conduct FTIR in paraffinized sections of breast tissue, and initial observations show a correlation between HAP carbonate substitution and tissue pathology. It is hoped that this and further studies will give insight into how the calcifications are linked to the disease process and will give an increased understanding of the significance of calcifications in breast tissue. If type II microcalcifications can be differentiated in benign and malignant tissue by spectroscopic techniques, this may have positive implications in early diagnosis if the techniques can be applied in vivo and spectroscopy of paraffin sections enables biochemical information to accompany histopathology of the sample.

  17. FTIR analysis of printed-circuit board residue

    SciTech Connect

    Myers, S.A.; Cognata, T.D.; Gotts, H.

    1996-12-31

    Logic boards were failing at Enhanced Mac Minus One (EMMO) test or Integrated Circuit Test (ICT) after printed circuit board (PCB) rework. A resistor in the microcontroller circuit was identified on the flip side of the PCB. Several areas on the board, including the resistor R161, were seen to have a slight white haze/low gloss appearance on the surface of the PCB. To test if the residue was electrically conductive, five boards were selected whose sole failure was R161. The resistance of the individual resistors was measured with a digital multimeter (DMM). The resistor was then cleaned with isopropyl alcohol and a cotton swab. Each board was retested at ICT and the individual resistors measured again with a DMM. Cleaning the area surrounding the resistor with isopropyl alcohol, corrected the failure four of the times. Material was removed from the resistor and board surfaces by physically abrading the organic coating and transferring the abraded material to an infrared transparent substrate (single crystal silicon). FTIR spectra were collected in the transmittance mode using a Bio-Rad UMA 500 FTIR microscope using a circular aperture (40 micron diameter).

  18. FTIR and EDXRF investigations of salt tolerant soybean mutants

    NASA Astrophysics Data System (ADS)

    Akyuz, Sevim; Akyuz, Tanil; Celik, Ozge; Atak, Cimen

    2013-07-01

    Molecular structure and elemental composition of soybean (Glycine max L. Merr.) seeds of S04-05 (Ustun-1) variety together with its salt tolerant mutants were investigated by Fourier transform infrared (FTIR) and energy dispersive X-ray fluorescence (EDXRF) spectrometry. Salt tolerant soybean mutants were in vivo and in vitro selected from the M2 generation of gamma irradiated S04-05 soybean variety. Examination of the secondary structure of proteins revealed the presence of some alterations in soybean mutants in comparison to those of the control groups. The difference IR spectra indicated that salt tolerant mutants (M2) have less protein but more lipid contents. Chemometric treatment of the FTIR data was performed and principle component analysis (PCA) revealed clear difference between control group of seeds and mutants. EDXRF analysis showed that salt tolerant mutants considerably contained more chlorine, copper and zinc elements when compared to the control group, although most of the trace elements concentrations were not significantly altered.

  19. FTIR Spectroscopy Applied in Remazol Blue Dye Oxidation by Laccases

    NASA Astrophysics Data System (ADS)

    Juárez-Hernández, J.; Zavala-Soto, M. E.; Bibbins-Martínez, M.; Delgado-Macuil, R.; Díaz-Godinez, G.; Rojas-López, M.

    2008-04-01

    We have used FTIR with attenuated total reflectance (ATR) technique to analyze the decolourization process of Remazol Blue dye (RB19) caused by the oxidative activity of laccase enzyme. It is known that laccases catalyze the oxidation of a large range of phenolic compounds and aromatic amines carrying out one-electron oxidations, although also radicals could be formed which undergo subsequent nonenzymatic reactions. The enzyme laccase is a copper-containing polyphenol oxidase (EC 1.10.3.2) which has been tested as a potential alternative in detoxification of environmental pollutants such as dyes present in wastewaters generated for the textile industry. In order to ensure degradation or avoid formation of toxic compounds it is important to establish the mechanism by which laccase oxidizes dyes. In this research individual ATR-FTIR spectra have been recorded for several reaction times between 0 to 236 hours, and the temporal dependence of the reaction was analyzed through the relative diminution of the intensity of the infrared band at 1127 cm-1 (associated to C-N vibration), with respect to the intensity of the band at 1104 cm-1 (associated to S = O) from sulphoxide group. Decolourization process of this dye by laccase could be attributed to its accessibility on the secondary amino group, which is a potential point of attack of laccases, abstracting the hydrogen atom. This decolourization process of remazol blue dye by laccase enzyme might in a future replace the traditionally high chemical, energy and water consuming textile operations.

  20. Ultrasound stimulated release of mimosa medicine from cellulose hydrogel matrix.

    PubMed

    Jiang, Huixin; Tovar-Carrillo, Karla; Kobayashi, Takaomi

    2016-09-01

    Ultrasound (US) drug release system using cellulose based hydrogel films was developed as triggered to mimosa. Here, the mimosa, a fascinating drug to cure injured skin, was employed as the loading drug in cellulose hydrogel films prepared with phase inversion method. The mimosa hydrogels were fabricated from dimethylacetamide (DMAc)/LiCl solution in the presence of mimosa, when the solution was exposed to ethanol vapor. The US triggered release of the mimosa from the hydrogel matrix was carried out under following conditions of US powers (0-30W) and frequencies (23, 43 and 96kHz) for different mimosa hydrogel matrix from 0.5wt% to 2wt% cellulose solution. To release the drug by US trigger from the matrix, the better medicine release was observed in the matrix prepared from the 0.5wt% cellulose solution when the 43kHz US was exposed to the aqueous solution with the hydrogel matrix. The release efficiency increased with the increase of the US power from 5 to 30W at 43kHz. Viscoelasticity of the hydrogel matrix showed that the hydrogel became somewhat rigid after the US exposure. FT-IR analysis of the mimosa hydrogel matrixes showed that during the US exposure, hydrogen bonds in the structure of mimosa-water and mimosa-cellulose were broken. This suggested that the enhancement of the mimosa release was caused by the US exposure. PMID:27150786

  1. In situ Carica papaya stem matrix and Fusarium oxysporum (NCBT-156) mediated bioremediation of chromium.

    PubMed

    Amatussalam, A; Abubacker, M N; Rajendran, R Babu

    2011-12-01

    Removal of heavy metal chromium was carried out using the fungus Fusarium oxysporum NCBT-156 strain isolated from soil of leather tanning effluent in in situ condition using potassium dichromate solution with 10 per cent Czapek-dox liquid medium. Biosorbent matrix was developed using Carica papaya plant dry stem to colonize the fungal strain to facilitate bioabsorption process. Bioabsorption of chromium was by metabolically mediated intracellular accumulation process. Maximum efficiency of chromium removal by biosorption upto 90 per cent was achieved at the end of 5th day of incubation (120 h of contact time) for 100 and 200 ppm concentration, upto 80 per cent for 300 and 400 ppm, and upto 65 per cent for 500 ppm to 1000 ppm concentrations with pH ranging from 5.8, 5.6, 5.5, 5.4 and 5.2, respectively for 100, 200, 300, 400, 500-1000 ppm concentration. SDS-PAGE protein profile showed significant difference in 34 kDa protein band after chromium absorption by the fungus. FTIR spectroscopic analysis revealed that the main functional groups involved in the uptake of chromium by F. oxysporium strain were carbonyl, carboxyl, amino and hydroxyl groups. PMID:22403866

  2. Abalone water-soluble matrix for self-healing biomineralization of tooth defects.

    PubMed

    Wen, Zhenliang; Chen, Jingdi; Wang, Hailiang; Zhong, Shengnan; Hu, Yimin; Wang, Zhili; Zhang, Qiqing

    2016-10-01

    Enamel cannot heal by itself if damaged. Hydroxyapatite (HAP) is main component of human enamel. Formation of enamel-like materials for healing enamel defects remains a challenge. In this paper, we successfully isolated the abalone water-soluble matrix (AWSM) with 1.53wt% the abalone water-soluble protein (AWSPro) and 2.04wt% the abalone water-soluble polysaccharide (AWSPs) from abandoned abalone shell, and self-healing biomineralization of tooth defects was successfully achieved in vitro. Based on X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), hot field emission scanning electron microscopy (HFESEM) and energy dispersive spectrometer (EDS) analysis, the results showed that the AWSM can efficiently induce remineralization of HAP. The enamel-like HAP was successfully achieved onto etched enamel's surface due to the presence of the AWSM. Moreover, the remineralized effect of eroded enamel was growing with the increase of the AWSM. This study provides a solution to the resource waste and environmental pollution caused by abandoned abalone shell, and we provides a new method for self-healing remineralization of enamel defects by AWSM and develops a novel dental material for potential clinical dentistry application. PMID:27287112

  3. Landscape matrix mediates occupancy dynamics of Neotropical avian insectivores

    USGS Publications Warehouse

    Kennedy, Christina M.; Campbell Grant, Evan H.; Neel, Maile C.; Fagan, William F.; Marpa, Peter P.

    2011-01-01

    In addition to patch-level attributes (i.e., area and isolation), the nature of land cover between habitat patches (the matrix) may drive colonization and extinction dynamics in fragmented landscapes. Despite a long-standing recognition of matrix effects in fragmented systems, an understanding of the relative impacts of different types of land cover on patterns and dynamics of species occurrence remains limited. We employed multi-season occupancy models to determine the relative influence of patch area, patch isolation, within-patch vegetation structure, and landscape matrix on occupancy dynamics of nine Neotropical nsectivorous birds in 99 forest patches embedded in four matrix types (agriculture, suburban evelopment, bauxite mining, and forest) in central Jamaica. We found that within-patch vegetation structure and the matrix type between patches were more important than patch area and patch isolation in determining local colonization and local extinction probabilities, and that the effects of patch area, isolation, and vegetation structure on occupancy dynamics tended to be matrix and species dependent. Across the avian community, the landscape matrix influenced local extinction more than local colonization, indicating that extinction processes, rather than movement, likely drive interspecific differences in occupancy dynamics. These findings lend crucial empirical support to the hypothesis that species occupancy dynamics in fragmented systems may depend greatly upon the landscape context.

  4. Vibration isolation

    NASA Technical Reports Server (NTRS)

    Bastin, Paul

    1990-01-01

    Viewgraphs on vibration isolation are presented. Techniques to control and isolate centrifuge disturbances were identified. Topics covered include: disturbance sources in the microgravity environment; microgravity assessment criteria; life sciences centrifuge; flight support equipment for launch; active vibration isolation system; active balancing system; and fuzzy logic control.

  5. Matrix cracking in ceramic-matrix composites

    SciTech Connect

    Danchaivijit, S.; Shetty, D.K. . Dept. of Materials Science and Engineering)

    1993-10-01

    Matrix cracking in ceramic-matrix composites with unbonded frictional interface has been studied using fracture mechanics theory. The critical stress for extension of a fiber-bridged crack has been analyzed using the stress-intensity approach. The analysis uses a new shear-lag formulation of the crack-closure traction applied by the bridging fibers based on the assumption of a constant sliding friction stress over the sliding length of the fiber-matrix interface. The new formulation satisfies two required limiting conditions: (a) when the stress in the bridging fiber approaches the far-field applied stress, the crack-opening displacement approaches a steady-state upper limit that is in agreement with the previous formulations; and (b) in the limit of zero crack opening, the stress in the bridging fiber approaches the far-field fiber stress. This lower limit of the bridging stress is distinctly different from the previous formulations. For all other conditions, the closure traction is a function of the far-field applied stress in addition to the local crack-opening displacement, the interfacial sliding friction stress, and the material properties. Numerical calculations using the stress-intensity approach indicate that the critical stress for crack extension decreases with increasing crack length and approaches a constant steady-state value for large cracks. The steady-state matrix-cracking stress agrees with a steady-state energy balance analysis applied to the continuum model, but it is slightly less than the matrix-cracking stress predicted by such theories of steady-state cracking as that of Aveston, Cooper, and Kelly. The origin of this difference and a method for reconciliation of the two theoretical approaches are discussed.

  6. MATRIX AND VECTOR SERVICES

    Energy Science and Technology Software Center (ESTSC)

    2001-10-18

    PETRA V2 provides matrix and vector services and the ability construct, query, and use matrix and vector objects that are used and computed by TRILINOS solvers. It provides all basic matr5ix and vector operations for solvers in TRILINOS.

  7. Matrix metalloproteinases and epileptogenesis.

    PubMed

    Ikonomidou, Chrysanthy

    2014-12-01

    Matrix metalloproteinases are vital drivers of synaptic remodeling in health and disease. It is suggested that at early stages of epileptogenesis, inhibition of matrix metalloproteinases may help ameliorate cell death, aberrant network rewiring, and neuroinflammation and prevent development of epilepsy. PMID:26567100

  8. Transfer function matrix

    NASA Technical Reports Server (NTRS)

    Seraji, H.

    1987-01-01

    Given a multivariable system, it is proved that the numerator matrix N(s) of the transfer function evaluated at any system pole either has unity rank or is a null matrix. It is also shown that N(s) evaluated at any transmission zero of the system has rank deficiency. Examples are given for illustration.

  9. Time rate collision matrix

    SciTech Connect

    Stoenescu, M.L.; Smith, T.M.

    1980-02-01

    The collision integral terms in Boltzmann equation are reformulated numerically leading to the substitution of the multiple integrals with a multiplicative matrix of the two colliding species velocity distribution functions which varies with the differential collision cross section. A matrix of lower rank may be constructed when one of the distribution functions is specified, in which case the matrix elements represent kinetic transition probabilities in the velocity space and the multiplication of the time rate collision matrix with the unknown velocity distribution function expresses the time rate of change of the distribution. The collision matrix may be used to describe the time evolution of systems in nonequilibrium conditions, to evaluate the rate of momentum and energy transfer between given species, or to generate validity criteria for linearized kinetic equations.

  10. Grassmann matrix quantum mechanics

    NASA Astrophysics Data System (ADS)

    Anninos, Dionysios; Denef, Frederik; Monten, Ruben

    2016-04-01

    We explore quantum mechanical theories whose fundamental degrees of freedom are rectangular matrices with Grassmann valued matrix elements. We study particular models where the low energy sector can be described in terms of a bosonic Hermitian matrix quantum mechanics. We describe the classical curved phase space that emerges in the low energy sector. The phase space lives on a compact Kähler manifold parameterized by a complex matrix, of the type discovered some time ago by Berezin. The emergence of a semiclassical bosonic matrix quantum mechanics at low energies requires that the original Grassmann matrices be in the long rectangular limit. We discuss possible holographic interpretations of such matrix models which, by construction, are endowed with a finite dimensional Hilbert space.

  11. Matrix isolation studies of the interactions of BF3 with water and substituted diethyl ethers. Chemical ionization mass spectrometric determination of the proton affinity of (CF3CH2)2O

    NASA Technical Reports Server (NTRS)

    Ball, David W.; Zehe, Michael J.

    1993-01-01

    BF3 was co-condensed with H2O, D2O, (C2H5)2O, (CF3CH2)2O, and (C2F5)2O in excess argon at 15 K. Infrared spectra of BF3/water isolated in solid argon provided a more complete analysis of the BF3--H2O complex than previously published. Infrared spectra of the matrices showed a definite Lewis acid-base interaction between BF3 and diethyl ether; a weak but definite interaction with bis (2,2,2-trifluorodiethyl) ether, and no observable interaction with perfluorodiethyl ether. Thus, the ether data indicate a clear trend between strength of interaction with BF3 and the degree of F substitution. To support and explain the emerging relationship between interaction strength and the basicity of the oxygen-containing molecule, the proton affinity of (CF3CH2)2O was measured using chemical ionization mass spectrometry. The implications of the results for lubricant/metal oxide surface interactions are discussed.

  12. Precision FT-IR laboratory measurements of atmospheric molecule

    NASA Astrophysics Data System (ADS)

    Sung, K.; Brown, L. R.; Crawford, T. J.

    2014-12-01

    Spectroscopic information is crucial a priori input to interpret atmospheric spectroscopic observations through radiative transfer modeling. The spectroscopic observations lead us to determine the physical and chemical conditions (e.g., atmospheric pressure, temperatures, composition, abundances …). In order to avoid false interpretations of the observed spectra, the molecular spectroscopic information (either line parameters or cross sections) must be sufficiently accurate and complete. To achieve this goal, we employ a broad-band Fourier transform spectrometer, Bruker IFS-125HR equipped with multiple detectors (He-cooled bolometers, N2-cooled MCT and InSb, warm InGaAs, Boron-doped silicates, photodiode) and beamsplitters (Mylars, KBr, CaF2, Quartz) sufficient to cover entire infrared spectra region from 20 to 15000 cm-1. We vacuum-couple up to 15 different absorption cells to the FT-IR, including five coolable cells with optical path lengths ranging from 0.02 m to 52 m; three of them are capable of reaching temperatures down to 50 K. We also have one heatable cell reaching 400 K. Finally, an extra vacuum chamber newly implemented to the Bruker 125HR enables both emission and absorption spectroscopy utilizing the emission port of the FT-IR. Recently, several studies of atmospheric molecules have been completed using the FT-IR at JPL in support of the Earth, terrestrial and planetary atmospheric remote sensing. These include analyses of C3H8 (propane) and 16O12C17O mid- and near-infrared regions, 13C12CH6 and 12C2H6 at longer wavelengths. In addition, we are studying the O2(A) line mixing and collision-induced absorption in the O2 A-band at 0.76 μm, as well as temperature-dependent cross sections of C6H6 (benzene) and C3H6 (propene) in the mid-infrared region. We will present an overview of results and work in progress. [Research described in this paper was performed at the Jet Propulsion Laboratory, California Institute of Technology, Connecticut College, and

  13. FTIR-Microspectroscopy of Prion-Infected Nervous Tissue

    SciTech Connect

    Kretlow,A.; Wang, Q.; Kneipp, J.; Lasch, P.; Beekes, M.; Miller, L.; Naumann, D.

    2006-01-01

    The family of transmissible spongiform encephalopathies (TSE), also termed prion diseases, is a group of fatal, neurodegenerative diseases characterized by the accumulation of a misfolded protein, the disease-associated prion protein PrPSc. This glycoprotein differs in secondary structure from its normal, cellular isoform PrPC, which is physiologically expressed mostly by neurons. Scrapie is a prion disease first described in the 18th century in sheep and goats, and has been established as a model in rodents to study the pathogenesis and pathology of prion diseases. Assuming a multitude of molecular parameters change in the tissue in the course of the disease, FTIR microspectroscopy has been proposed as a valuable new method to study and identify prion-affected tissues due to its ability to detect a variety of changes in molecular structure and composition simultaneously. This paper reviews and discusses results from previous FTIR microspectroscopic studies on nervous tissue of scrapie-infected hamsters in the context of histological and molecular alterations known from conventional pathogenesis studies. In particular, data from studies reporting on disease-specific changes of protein structure characteristics, and also results of a recent study on hamster dorsal root ganglia (DRG) are discussed. These data include an illustration on how the application of a brilliant IR synchrotron light source enables the in situ investigation of localized changes in protein structure and composition in nervous cells or tissue due to PrPSc deposition, and a demonstration on how the IR spectral information can be correlated with results of complementary studies using immunohistochemistry and x-ray fluorescence techniques. Using IR microspectroscopy, some neurons exhibited a high accumulation of disease-associated prion protein evidenced by an increased amount of beta-sheet at narrow regions in or around the infected nervous cells. However, not all neurons from terminally diseased

  14. Effect of carboxymethylation on rheological and drug release characteristics of locust bean gum matrix tablets.

    PubMed

    Chakravorty, Amrita; Barman, Gouranga; Mukherjee, Sudipta; Sa, Biswanath

    2016-06-25

    This study was undertaken to investigate correlation between the carboxymethylation-induced rheological changes and drug release characteristics of locust bean gum (LBG) matrix tablets. LBG was derivatized to carboxymethyl LBG (CMLBG) and characterized by (13)C NMR, FTIR and elemental analyses. Rheological studies revealed that LBG, in contact with water, produced a strong elastic gel which swelled less due to lower penetration of water resulting in slower drug release. On the other hand, CMLBG formed a viscous polymer solution through which higher influx of water resulted in rapid swelling of the matrix and faster drug release. Although the release from a particular matrix was dependent on drugs' solubilities, CMLBG matrix tablet produced faster release of all the drugs than LBG matrix tablets. In conclusion, rheological study appeared to be an useful tool to predict release of drugs from polysaccharide matrix tablets. PMID:27083792

  15. [Raman, FTIR spectra and normal mode analysis of acetanilide].

    PubMed

    Liang, Hui-Qin; Tao, Ya-Ping; Han, Li-Gang; Han, Yun-Xia; Mo, Yu-Jun

    2012-10-01

    The Raman and FTIR spectra of acetanilide (ACN) were measured experimentally in the regions of 3 500-50 and 3 500-600 cm(-1) respectively. The equilibrium geometry and vibration frequencies of ACN were calculated based on density functional theory (DFT) method (B3LYP/6-311G(d, p)). The results showed that the theoretical calculation of molecular structure parameters are in good agreement with previous report and better than the ones calculated based on 6-31G(d), and the calculated frequencies agree well with the experimental ones. Potential energy distribution of each frequency was worked out by normal mode analysis, and based on this, a detailed and accurate vibration frequency assignment of ACN was obtained. PMID:23285870

  16. Diffusion of water in diopside from Kunlun Mts. by FTIR

    NASA Astrophysics Data System (ADS)

    Ferriss, E.; Plank, T.; Walker, D.

    2012-12-01

    Diffusion of hydrogen and other water-related species in clinopyroxenes has potential for use quantifying the ascent rate of magma near the surface of the Earth and has implications for our understanding of water in the mantle. Previous work on diopside has yielded diffusivities that range over four orders of magnitude (e.g., very fast diffusion in Woods et al. 2000 versus slow diffusion in Sundvall et al. 2011), and the relationship between diffusivity and mineral chemistry is still poorly understood. The diffusivity of water has been investigated in natural low-Fe (Mg number: 98.3) diopside from the Kunlun Mts., China supplied by the curator of the American Museum of Natural History (AMNH) mineral collection. Polished, small (typically 1.5-2 mm × 1.5-2 mm × 1.5-2 mm) blocks were oriented and heated at 1 atm in a vertical gas-mixing furnace. The samples were held in gold wire, and the oxygen fugacity was buffered at the quartz-fayalite-magnetite buffer (QFM) using a mixture of CO and CO2. Fourier transform infrared spectroscopy (FTIR, at AMNH) was used to measure the water content based on absorption peaks between wavenumbers 3000 and 4000 cm-1. The initial water content (33 ppm) was estimated using polarized spectra obtained in three orthogonal directions and the calibration of Bell et al. (1995). Integrated peak areas were obtained from FTIR spectra through the edges of the uncut, heated block using a linear baseline from wavenumbers 3500-3700 cm-1 and 3200-3700 cm-1 for spectra taken with the polarized infrared beam traveling parallel to [001] and [010], respectively. Diffusion profiles were obtained in each direction by normalizing these peak areas to the initial peak area measured prior to heating in each direction. The interpretation of these profiles and determination of diffusivities is complicated by the interdependence of the profiles and the fact that each FTIR measurement represents an average value of the water contents through the sample

  17. Photoacoustic Fourier Transform Infrared (FTIR) Spectroscopy Of Solids

    NASA Astrophysics Data System (ADS)

    Vidrine, D. Warren

    1981-10-01

    After discovering the photoacoustic effect, Alexander Graham Bell predicted its use in spectrometers, and that it would find its greatest utility "in the ultra-red." More than ninety years were required to fulfil his first prediction, and the second is still a prophecy. There is no record whether he ever imagined that an invention being developed that same winter by a young protege of his named Albert Michelson would ever be combined with his photoacoustic effect. A century later, the combination was made by Farrow Burnham, and Eyring, using a visible-range interferometer spectrometer of their own design. Soon afterwards, Rockley and myself, working independently, applied the technique to infrared measurements of solid samples. Photoacoustic cells are now commercially available as FT-IR accessories, and the technique is in use in the field.

  18. Corrosion inhibitor film formation studied by ATR-FTIR

    SciTech Connect

    Campbell, S.; Jovancicevic, V.

    1999-11-01

    The development of an inhibitor film is essential for the effective performance of a corrosion inhibitor. The use of attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR) allows the development of inhibitor films on iron oxides to be monitored. For two distinct corrosion inhibitor chemistries, oleic imidazoline and phosphate ester, the film formation and corrosion processes are monitored on Fe{sub 3}O{sub 4} in a powdered form (a model surface). Additional data following on the physical and chemical properties are obtained using XPS and SEM techniques, which allows for a more complete characterization of the model inhibitor/oxide system. By the proper choice of system and measurement techniques, the complex phenomenon of corrosion inhibition may be analyzed directly.

  19. FTIR studies of low temperature sulfuric acid aerosols

    NASA Technical Reports Server (NTRS)

    Anthony, S. E.; Tisdale, R. T.; Disselkamp, R. S.; Tolbert, M. A.; Wilson, J. C.

    1995-01-01

    Sub-micrometer sized sulfuric acid H2SO4 particles were generated using a constant output atomizer source. The particles were then exposed to water vapor before being injected into a low temperature cell. Multipass transmission Fourier Transformation Infrared (FTIR) spectroscopy was used to determine the phase and composition of the aerosols as a function of time for periods of up to five hours. Binary H2SO4H2O aerosols with compositions from 35 to 95 wt % H2SO4 remained liquid for over 3 hours at room temperatures ranging from 189-240 K. These results suggest that it is very difficut to freeze SSAs via homogeneous nucleation. Attempts to form aerosols more dilute than 35 wt % H2SO4 resulted in ice formation.

  20. FTIR Spectroscopic Characterization Of II-VI Semiconductors

    NASA Technical Reports Server (NTRS)

    Perry, G. L. E.; Szofran, F. R.

    1991-01-01

    Combination of commercial Fourier-transform infrared (FTIR) spectrometer with computer and special-purpose software constitutes highly automated facility for acquisition and processing of infrared transmission or reflection spectral image data. Intended principally to acquire transmission spectra of some compounds of elements in groups II and VI of periodic table. System used to characterize specimens of II/VI alloy semiconductors grown by directional solidification and quenching. Transmission-edge maps helpful in studies of flows, gradients of temperature, and coefficients of diffusion in solidifying melts. Data acquired by system include optical characteristics, and they both verify and complement data obtained by such other techniques as measurements of density and x-ray-dispersion analysis.

  1. Increasing FTIR spectromicroscopy speed and resolution through compressive imaging

    SciTech Connect

    Gallet, Julien; Riley, Michael; Hao, Zhao; Martin, Michael C

    2007-10-15

    At the Advanced Light Source at Lawrence Berkeley National Laboratory, we are investigating how to increase both the speed and resolution of synchrotron infrared imaging. Synchrotron infrared beamlines have diffraction-limited spot sizes and high signal to noise, however spectral images must be obtained one point at a time and the spatial resolution is limited by the effects of diffraction. One technique to assist in speeding up spectral image acquisition is described here and uses compressive imaging algorithms. Compressive imaging can potentially attain resolutions higher than allowed by diffraction and/or can acquire spectral images without having to measure every spatial point individually thus increasing the speed of such maps. Here we present and discuss initial tests of compressive imaging techniques performed with ALS Beamline 1.4.3?s Nic-Plan infrared microscope, Beamline 1.4.4 Continuum XL IR microscope, and also with a stand-alone Nicolet Nexus 470 FTIR spectrometer.

  2. Synchrotron-based highest resolution FTIR spectroscopy of chlorobenzene

    NASA Astrophysics Data System (ADS)

    Albert, Sieghard; Keppler, Karen; Lerch, Philippe; Quack, Martin; Wokaun, Alexander

    2015-09-01

    We report the Fourier Transform Infrared (FTIR) spectrum of chlorobenzene (C6H5Cl) measured using synchrotron radiation and the ETH-SLS 2009 prototype spectrometer at the Swiss Light Source (SLS). The maximum optical path difference of these measurements was 11.8 m leading to a resolution of better than 0.0008 cm-1. The spectra were taken at room temperature in the range 600-900 cm-1. It was possible to analyze the in-plane mode ν12 of A1 symmetry (ν˜0 = 706.6686 cm-1) and the out-of-plane mode ν10b of B1 symmetry (ν˜0 = 741.2240 cm-1) of C6H535Cl. In addition, the ground state constant ΔK of C6H535Cl has been readjusted using combination differences (CD).

  3. [Quantitative analysis of transformer oil dissolved gases using FTIR].

    PubMed

    Zhao, An-xin; Tang, Xiao-jun; Wang, Er-zhen; Zhang, Zhong-hua; Liu, Jun-hua

    2013-09-01

    For the defects of requiring carrier gas and regular calibration, and low safety using chromatography to on line monitor transformer dissolved gases, it was attempted to establish a dissolved gas analysis system based on Fourier transform infrared spectroscopy. Taking into account the small amount of characteristic gases, many components, detection limit and safety requirements and the difficulty of degasser to put an end to the presence of interference gas, the quantitative analysis model was established based on sparse partial least squares, piecewise section correction and feature variable extraction algorithm using improvement TR regularization. With the characteristic gas of CH4, C2H6, C2H6, and CO2, the results show that using FTIR meets DGA requirements with the spectrum wave number resolution of 1 cm(-1) and optical path of 10 cm. PMID:24369641

  4. Tamoxifen-model membrane interactions: an FT-IR study

    NASA Astrophysics Data System (ADS)

    Boyar, Handan; Severcan, Feride

    1997-06-01

    The temperature- and concentration-induced effects of tamoxifen (TAM) on dipalmitoyl phosphatidylcholine (DPPC) model membranes were investigated by the Fourier transform-infrared (FT-IR) spectroscopic technique. An investigation of the C-H stretching region and the CO mode reveals that the inclusion of TAM changes the physical properties of the DPPC multibilayers by (i) shifting the main phase transition to lower temperatures; (ii) broadening the transition profile slightly; (iii) disordering the system in the gel and in the liquid crystalline phases; (iv) increasing the dynamics in the gel phase and decreasing the dynamics of the acyl chains in the liquid crystalline phase; (v) increasing the mobility of the terminal methyl group region of the bilayer in the gel phase and decreasing it in the liquid crystalline phase; (vi) increasing the frequency of the CO stretching mode both in the gel and in the liquid crystalline phases, i.e. non-bonding with carbonyl groups.

  5. Raman/FTIR spectroscopy of oil shale retort gases

    SciTech Connect

    Richardson, J H; Monaco, S B; Sanborn, R H; Hirschfeld, T B; Taylor, J R

    1982-08-01

    A Raman facility was assembled in order to aid in the evaluation of the feasibility of using Raman or FTIR spectroscopy for analyzing gas mixtures of interest in oil shale. Applications considered in oil shale research included both retort monitoring and laboratory kinetic studies. Both techniques gave limits of detection between 10 and 1000 ppM for ten representative pertinent gases. Both techniques are inferior as a general analytical technique for oil shale gas analysis in comparison with mass spectroscopy, which had detection limits between 1 and 50 ppM for the same gases. The conclusion of the feasibility study was to recommend that mass spectroscopic techniques be used for analyzing gases of interest to oil shale.

  6. Ground-based passive FT-IR spectrometry

    NASA Astrophysics Data System (ADS)

    Knapp, Robert B.; Combs, Roger J.; Kroutil, Robert T.

    2002-02-01

    Absorbance and transmittance spectra were acquired with ground-based passive FT-IR spectrometry for industrial stack evaluations and open-air controlled vapor generation experiments. The industrial stack effluents of sulfur dioxide and nitrous oxide were detected from a coal-burning power plant and an acid plant, respectively, with both MWIR and LWIR passive sensors. The controlled open-air experiments relied on only a LWIR sensor. These experiments produced plumes of methanol and ethanol at three and four elevated plume temperatures, respectively. Various vapor concentration pathlength produces of both ethanol and methanol were generated and gravimetrically monitored in the range from 0 to 300 ppm-m. The associated absorbance values for these concentration pathlength products were found to obey Beer's Law for each elevate stack temperature of 125, 150, 175, and 200 degrees C.

  7. Hot exhaust gases with passive FTIR emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Heland, Joerg; Schaefer, Klaus; Haus, Rainer

    1998-12-01

    Passive FTIR emission spectroscopy using a commercial medium resolution instrument with a telescope has been applied to analyze the hot exhaust gases of various combustion sources, such as industrial and building smoke stacks, aircraft engines, flares, and forest fires. To interpret the remotely measured spectra a multi-layer, line-by-line spectra retrieval software using the molecular spectral databases HITRAN and HITEMP has been developed, validated and successfully used to determine the exhaust gas temperatures and the concentrations of CO2, H2O, CO, N2O, CH4, NO, NO2, SO2, and HCl for different combustion conditions of the sources. In this paper the feasibility and the setup of passive IR measurements, the basic theory of radiative transfer and special features of the commercially available spectra analysis code are described. In addition, the results of the different measurement applications are summarized.

  8. In situ-ATR-FTIR analysis on the uptake and release of streptomycin from polyelectrolyte complex layers

    NASA Astrophysics Data System (ADS)

    Torger, B.; Müller, M.

    2013-03-01

    In-situ ATR-FTIR spectroscopy and line shape analysis of the diagnostic spectral region was used to quantify the bound amount and release of the antibiotic streptomycin (STRP) at polyelectrolyte (PEL) multilayers (PEM) of poly(ethyleneimine) (PEI) and poly(acrylic acid) (PAA) or PEI and sodium alginate (ALG). Unlike common concepts based on the drug enrichment of the release medium, this analytical concept allowed to measure quantitatively the drug depletion in the delivery matrix. The measured kinetic in situ ATR-FTIR data were analysed by a modified Korsmeyer-Peppas equation based on two characteristic release parameters k and n. As main experimental parameters the number of PEL layers (adsorption steps) z and the STRP/PEL ratio were varied. For z = 8 the STRP/PEL ratio showed the most significant influence on release kinetics, whereby for STRP/PEL = 1:25 slowest (n = 0.77) and lowest (k = 21.4%) and for STRP/PEL = 1:5 most rapid (n = 0.30) and highest (k = 58.6%) drug releases were found. PEM-PEI/ALG-8 (STRP/PEL = 1:5) revealed slower release rates (n = 0.58) and lower released STRP amounts (k = 17.1%) compared to PEI/PAA. UV-VIS data on time dependent STRP enrichment of the release medium showed a similar trend compared to respective ATR-FTIR data on STRP depletion in PEM. Released amounts of around 1-2 mg from the herein introduced PEM films could be determined. The introduced analytical concept will be used as screening tool for other drugs, drug eluting films and bone substituting materials.

  9. Analyzing the impact of different excipients on drug release behavior in hot-melt extrusion formulations using FTIR spectroscopic imaging.

    PubMed

    Pudlas, Marieke; Kyeremateng, Samuel O; Williams, Leonardo A M; Kimber, James A; van Lishaut, Holger; Kazarian, Sergei G; Woehrle, Gerd H

    2015-01-25

    The drug release performance of hot-melt extrudate formulations is mainly affected by its composition and interactions between excipients, drug and the dissolution media. For targeted formulation development, it is crucial to understand the role of these interactions on the drug release performance of extrudate formulations. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic imaging was used with an in-situ flow-cell device to analyze the impact of different excipients on drug release from extrudates. The compositions differed in the type of polymer (copovidone and Soluplus®), the salt or acid form of ibuprofen and the addition of sodium carbonate. For comparison, conventional USP (United States Pharmacopeia) Apparatus 2 dissolution studies were performed. FTIR imaging revealed that differences in the drug release rate were mainly due to drug-polymer interactions. Ibuprofen acid showed interactions with the matrix polymer and exhibited a slower drug release compared to non-interacting ibuprofen salt. Addition of sodium carbonate to the ibuprofen acid containing formulations enhanced the drug release rate of these systems by interfering with the drug-polymer interactions. In addition, drug release rates also depended on the polymer type, showing faster drug release rates for extrudate formulations containing copovidone compared to Soluplus®. FTIR imaging revealed that the stronger the drug-polymer interaction in the formulations, the slower the drug release. The addition of sodium carbonate improved release as it reduces drug-polymer interactions and allows for the formation of the more water-soluble ibuprofen salt. PMID:25445833

  10. Assessing dysplasia of a bronchial biopsy with FTIR spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Foreman, Liberty; Kimber, James A.; Oliver, Katherine V.; Brown, James M.; Janes, Samuel M.; Fearn, Tom; Kazarian, Sergei G.; Rich, Peter

    2015-03-01

    An FTIR image of an 8 µm section of de-paraffinised bronchial biopsy that shows a histological transition from normal to severe dysplasia/squamous cell carcinoma (SCC) in situ was obtained in transmission by stitching together images of 256 x 256 µm recorded using a 96 x 96 element FPA detector. Each pixel spectrum was calculated from 128 co-added interferograms at 4 cm-1 resolution. In order to improve the signal to noise ratio, blocks of 4x4 adjacent pixels were subsequently averaged. Analyses of this spectral image, after conversion of the spectra to their second derivatives, show that the epithelium and the lamina propria tissue types can be distinguished using the area of troughs at either 1591, 1334, 1275 or 1215 cm-1 or, more effectively, by separation into two groups by hierarchical clustering (HCA) of the 1614-1465 region. Due to an insufficient signal to noise ratio, disease stages within the image could not be distinguished with this extent of pixel averaging. However, after separation of the cell types, disease stages within either the epithelium or the lamina propria could be distinguished if spectra were averaged from larger, manually selected areas of the tissue. Both cell types reveal spectral differences that follow a transition from normal to cancerous histology. For example, spectral changes that occurred in the epithelium over the transition from normal to carcinoma in situ could be seen in the 1200-1000 cm-1 region, particularly as a decrease in the second derivative troughs at 1074 and 1036 cm-1 , consistent with changes in some form of carbohydrate. Spectral differences that indicate a disease transition from normal to carcinoma in the lamina propria could be seen in the 1350-1175 cm-1 and 1125-1030 cm-1 regions. Thus demonstrating that a progression from healthy to severe dysplasia/squamous cell carcinoma (SCC) in situ can be seen using FTIR spectroscopic imaging and multivariate analysis.

  11. FTIR measurements of biomass burning species in the Arctic

    NASA Astrophysics Data System (ADS)

    Lutsch, E.; Viatte, C.; Strong, K.; Nussbaumer, E.; Hannigan, J. W.; Kasai, Y.

    2014-12-01

    We present time series of the total column amounts of carbon monoxide (CO), hydrogen cyanide(HCN), acetylene (C2H2), ethane (C2H6), formaldehyde (H2CO), formic acid (HCOOH) and methanol(CH3OH) obtained by Fourier Transform Infrared (FTIR) spectrometer measurements at three Arcticsites. Two are located in the high Arctic at Eureka, Nunavut (80.02°N, 86.42°W) and Thule, Greenland(76.53°N , 68.74°W), and the third is at Poker Flat, Alaska (65.11°N, 147.42°W). Total column amounts of each target species are obtained using the SFIT4 retrieval algorithm based onthe optimal estimation method, along with spectral line parameters from the HITRAN 2008spectroscopic database. The total column time series allow for biomass burning events to be identified at all three sites byenhancements of the total columns above ambient levels. HYSPLIT back-trajectories and MODIS firehot spot data are used to determine the burning source regions and the travel time durations of theplumes. The seasonal variabilities of the longer-lived species of CO, HCN, C2H2 and C2H6 are primarilydetermined by reactions with OH and long-range transport, while those of the shorter-lived species ofH2CO, HCOOH, CH3OH are most influenced by biogenic emissions and short-range transport. Thevarying lifetimes of these species and the independent measurements at the three sites allow for thetransport pathways to be investigated. By accounting for the effect of the aging of the smoke plumes,the measured FTIR enhancement ratios are corrected to obtain emission ratios and emission factors,which are needed to improve the simulation of fire emissions in chemical transport models.

  12. Raman and FTIR imaging of dynamic polymer systems

    NASA Astrophysics Data System (ADS)

    Bobiak, John Peter

    This work aims to expand the applications of Raman and infrared imaging in materials science and engineering. Recent developments in spectroscopic imaging technology have led to relatively fast image acquisition rates, enabling the in situ analysis of various engineering processes. A brief review of spectroscopic imaging principles and existing applications is provided as background before three novel applications are set forth. First, the effectiveness of FTIR imaging for modeling polymer dissolution behavior was examined in a series of binary poly (methyl methacrylate) (PMMA) systems. The dissolution behavior was influenced by polymer conformation as well as the solvent characteristics. The results indicate that chemistry alone is a poor predictor of dissolution rate. Rather, the diffusion coefficients of both the polymer and solvent have a foremost impact on the dissolution process. One major complication in modeling diffusion-related process by FTIR imaging is the precise determination of component locations in a series of images. This issue is addressed through the introduction of a new position-reporting technique based on hypothesis testing. A rudimentary drug release system, consisting of a poly (ethylene-co-vinyl acetate) film and a nicotine solution, was used to illustrate the importance of precisely reporting the nicotine diffusion front position. The new reporting method provided an inherent level of certainty to the position report. This method was applied to qualitatively assess the uptake of nicotine from solutions containing different solubilizing agents, which were capable of either promoting or inhibiting nicotine uptake. Finally, Raman mapping and Raman line imaging were used to classify individual carbon nanotubes that were dispersed on a substrate. Individual nanotubes displayed a range of spectral characteristics, indicating that the bulk sample was a mixture of materials with different graphitic domain sizes. The results from images acquired

  13. Mechanisms balancing skeletal matrix synthesis and degradation.

    PubMed Central

    Blair, Harry C; Zaidi, Mone; Schlesinger, Paul H

    2002-01-01

    Bone is regulated by evolutionarily conserved signals that balance continuous differentiation of bone matrix-producing cells against apoptosis and matrix removal. This is continued from embryogenesis, where the skeleton differentiates as a solid mass and is shaped into separate bones by cell death and proteolysis. The two major tissues of the skeleton are avascular cartilage, with an extracellular matrix based on type II collagen and hydrophilic proteoglycans, and bone, a stronger and lighter material based on oriented type I collagen and hydroxyapatite. Both differentiate from the same mesenchymal stem cells. This differentiation is regulated by a family of related signals centred on bone morphogenic proteins. Fibroblast growth factors, Indian hedgehog and parathyroid hormone-related protein are important in determining the type of matrix and the relation of skeletal and non-skeletal structures. Removal of mineralized matrix involves apoptosis of matrix cells and differentiation of acid-secreting cells (osteoclasts) from macrophage precursors. Key regulators of matrix removal are signals in the tumour-necrosis-factor family. Osteoclasts dissolve bone by isolating a region of the matrix and secreting HCl and proteinases at that site. Successive cycles of removal and replacement allow growth, repair and remodelling. The signals for bone turnover are predominantly cell-membrane-associated, allowing very specific spatial regulation. In addition to its support function, bone is a reservoir of Ca2+, PO3-(4) and OH-. Secondary modulation of mineral secretion and bone degradation are mediated by humoral signals, including parathyroid hormone and vitamin D, as well as the cytokines that also regulate the underlying cell differentiation. PMID:12023876

  14. Hybrid matrix amplifier

    DOEpatents

    Martens, J.S.; Hietala, V.M.; Plut, T.A.

    1995-01-03

    The present invention comprises a novel matrix amplifier. The matrix amplifier includes an active superconducting power divider (ASPD) having N output ports; N distributed amplifiers each operatively connected to one of the N output ports of the ASPD; and a power combiner having N input ports each operatively connected to one of the N distributed amplifiers. The distributed amplifier can included M stages of amplification by cascading superconducting active devices. The power combiner can include N active elements. The resulting (N[times]M) matrix amplifier can produce signals of high output power, large bandwidth, and low noise. 6 figures.

  15. Hybrid matrix amplifier

    DOEpatents

    Martens, Jon S.; Hietala, Vincent M.; Plut, Thomas A.

    1995-01-01

    The present invention comprises a novel matrix amplifier. The matrix amplifier includes an active superconducting power divider (ASPD) having N output ports; N distributed amplifiers each operatively connected to one of the N output ports of the ASPD; and a power combiner having N input ports each operatively connected to one of the N distributed amplifiers. The distributed amplifier can included M stages of amplification by cascading superconducting active devices. The power combiner can include N active elements. The resulting (N.times.M) matrix amplifier can produce signals of high output power, large bandwidth, and low noise.

  16. Measurement matrix optimization method based on matrix orthogonal similarity transformation

    NASA Astrophysics Data System (ADS)

    Pan, Jinfeng

    2016-05-01

    Optimization of the measurement matrix is one of the important research aspects of compressive sensing theory. A measurement matrix optimization method is presented based on the orthogonal similarity transformation of the information operator's Gram matrix. In terms of the fact that the information operator's Gram matrix is a singular symmetric matrix, a simplified orthogonal similarity transformation is deduced, and thus the simplified diagonal matrix that is orthogonally similar to it is obtained. Then an approximation of the Gram matrix is obtained by letting all the nonzero diagonal entries of the simplified diagonal matrix equal their average value. Thus an optimized measurement matrix can be acquired according to its relationship with the information operator. Results of experiments show that the optimized measurement matrix compared to the random measurement matrix is less coherent with dictionaries. The relative signal recovery error also declines when the proposed measurement matrix is utilized.

  17. Formulation and drug-content assay of microencapsulated antisense oligonucleotide to NF-κB using ATR-FTIR

    NASA Astrophysics Data System (ADS)

    Siwale, Rodney; Meadows, Fred; Mody, Vicky V.; Shah, Samit

    2013-09-01

    Antisense oligonucleotide to NF-κB sequence: 5‧-GGA AAC ACA TCC TCC ATG-3‧, was microencapsulated in an albumin matrix by the method of spray dryingTM. Spectral analysis was performed on varying drug loading formulations of both drugs by mid-IR attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). An out of plane O-H bending vibration at 948 cm-1, unique to both the native and microencapsulated drugs was identified. The calculated peak areas corresponded to the drug loadings in the microsphere formulations. A standard curve could then be used to determine the drug content of an unknown microsphere formulation. Accuracy and precision were determined to be comparable to other analytical techniques such as HPLC.

  18. Two-dimensional ATR-FTIR Spectroscopic Study on the Water Diffusion Behavior in Polyimide/Silica Nanocomposite

    NASA Astrophysics Data System (ADS)

    Shen, Yi; Wang, Hai-tao; Zhong, Wei; Wu, Pei-yi

    2006-12-01

    To consider the reliability and performance of electronic devices based on polyimide derivatives, dynamic water sorption and diffusion behavior in a polyimide derivative: poly(4'4-oxydiphenylene pyromellitimide) (PMDA-ODA)/silica nanocomposite was investigated by two-dimensional ATR-FTIR spectroscopy, by which three states of water molecules owning different H-bonding strength were distinguished. The amounts and strength of H-bonding also played a significant role in determining the diffusion rate of the different states of water molecules. The type of aggregated water molecules which also formed H-bonding with silicic acid (residues) or polyimide system was the last one diffusing to the polymer side in contact with the ATR crystal element because the polymeric matrix blocked their diffusion to a great extent. The diffusion coefficient was also estimated to gain the information of the dynamic diffusion behavior.

  19. Metal Matrix Composites

    SciTech Connect

    Hunt, Warren; Herling, Darrell R.

    2004-02-01

    Metal matrix composites have found selected application in areas that can cost-effectively capitalize on improvements in specific stiffness, specific strength, fatigue resistance, wear resistance, and coefficient of thermal expansion. Metal matrix composites comprise a relatively wide range of materials defined by the metal matrix, reinforcement type, and reinforcement geometry. In the area of the matrix, most metallic systems have been explored, including aluminum, beryllium, magnesium, titanium, iron, nickel, cobalt, and silver. However, aluminum is by far the most preferred. For reinforcements, the materials are typically ceramics, which provide a very beneficial combination of stiffness, strength, and relatively low density. Candidate reinforcement materials include SiC, Al2O3, B4C, TiC, TiB2, graphite, and a number of other ceramics. In addition, metallic materials such as tungsten and steel fibers have been considered.

  20. Pesticide-Exposure Matrix

    Cancer.gov

    The "Pesticide-exposure Matrix" was developed to help epidemiologists and other researchers identify the active ingredients to which people were likely exposed when their homes and gardens were treated for pests in past years.

  1. The Hill Interaction Matrix

    ERIC Educational Resources Information Center

    Hill, William Fawcett

    1971-01-01

    Leadership style, group composition, and group development are simultaneously quantified through the use of the matrix. It represents an attempt to objectify the art of group therapy. Comment by Richard C. Rank follows. (Author)

  2. Matrix computations in MACSYMA

    NASA Technical Reports Server (NTRS)

    Wang, P. S.

    1977-01-01

    Facilities built into MACSYMA for manipulating matrices with numeric or symbolic entries are described. Computations will be done exactly, keeping symbols as symbols. Topics discussed include how to form a matrix and create other matrices by transforming existing matrices within MACSYMA; arithmetic and other computation with matrices; and user control of computational processes through the use of optional variables. Two algorithms designed for sparse matrices are given. The computing times of several different ways to compute the determinant of a matrix are compared.

  3. A strategy to quantitate global phosphorylation of bone matrix proteins.

    PubMed

    Sroga, Grażyna E; Vashishth, Deepak

    2016-04-15

    Current studies of protein phosphorylation focus primarily on the importance of specific phosphoproteins and their landscapes of phosphorylation in the regulation of different cellular functions. However, global changes in phosphorylation of extracellular matrix phosphoproteins measured "in bulk" are equally important. For example, correct global phosphorylation of different bone matrix proteins is critical to healthy tissue biomineralization. To study changes of bone matrix global phosphorylation, we developed a strategy that combines a procedure for in vitro phosphorylation/dephosphorylation of fully mineralized bone in addition to quantitation of the global phosphorylation levels of bone matrix proteins. For the first time, we show that it is possible to enzymatically phosphorylate/dephosphorylate fully mineralized bone originating from either cadaveric human donors or laboratory animals (mice). Using our strategy, we detected the difference in the global phosphorylation levels of matrix proteins isolated from wild-type and osteopontin knockout mice. We also observed that the global phosphorylation levels of matrix proteins isolated from human cortical bone were lower than those isolated from trabecular bone. The developed strategy has the potential to open new avenues for studies on the global phosphorylation of bone matrix proteins and their role in biomineralization as well for other tissues/cells and protein-based materials. PMID:26851341

  4. Optical coherency matrix tomography

    PubMed Central

    Kagalwala, Kumel H.; Kondakci, H. Esat; Abouraddy, Ayman F.; Saleh, Bahaa E. A.

    2015-01-01

    The coherence of an optical beam having multiple degrees of freedom (DoFs) is described by a coherency matrix G spanning these DoFs. This optical coherency matrix has not been measured in its entirety to date—even in the simplest case of two binary DoFs where G is a 4 × 4 matrix. We establish a methodical yet versatile approach—optical coherency matrix tomography—for reconstructing G that exploits the analogy between this problem in classical optics and that of tomographically reconstructing the density matrix associated with multipartite quantum states in quantum information science. Here G is reconstructed from a minimal set of linearly independent measurements, each a cascade of projective measurements for each DoF. We report the first experimental measurements of the 4 × 4 coherency matrix G associated with an electromagnetic beam in which polarization and a spatial DoF are relevant, ranging from the traditional two-point Young’s double slit to spatial parity and orbital angular momentum modes. PMID:26478452

  5. Field evaluation of Fourier transform infrared continuous emissions monitoring (FTIR CEM) systems

    NASA Astrophysics Data System (ADS)

    Dunder, Thomas A.; Geyer, Thomas J.; Kinner, Laura L.; Plummer, Grant M.

    1995-02-01

    Recent environmental regulations, including the Clean Air Act and the Enhanced Monitoring Regulations, may require continuous emissions monitoring (CEM) of hazardous air pollutants (HAPs). A promising technique for this application is Fourier transform infrared spectroscopy (FTIR). FTIR spectroscopy can, in principle, be used to monitor virtually any gas phase species. Two evaluations of FTIR CEM systems are discussed. The first study, performed in 1993 - 94, compared two FTIR CEM systems on a side-by-side basis in an extended field test at two coal-fired electric power plants. The FTIR CEM systems monitored the legally mandated criteria pollutants and diluents (CO, CO2, NO, NO2, and SO2) as well as H2O. In addition, one system monitored two HAPs (HCl and HF) and NH3. The FTIR CEM measurements were compared with those from the compliance CEM systems at the facilities. Several relative accuracy test audits were also performed to verify the FTIR CEM accuracy. The second evaluation was recently commenced on behalf of the Environmental Protection Agency. In this study, FTIR CEM systems are evaluated specifically for the monitoring of HAP species by conducting laboratory and field tests. The evaluation culminates in the development of proposed performance specifications and protocols for FTIR CEM systems.

  6. Open-path and extractive FT-IR environmental monitoring above and below the ground

    SciTech Connect

    Fateley, W.G.; Hammaker, R.M.; Chaffin, C.T.; Marshall, T.L.

    1995-12-31

    To demonstrate the versatility of Fourier transform infrared (FT-IR) spectrometry, two site investigations are discussed. The first is the monitoring of emissions from active volcanoes. The second is the analysis of soil gases from a site that is currently under remediation for ground water and soil contamination. The monitoring performed at the volcanoes used open-path FT-IR methods and the monitoring at the remediation site used extractive FT-IR methods. Descriptions of the sampling systems employed and the missions monitored at these sites will be used to demonstrate the advantages and limitations of environmental monitoring using FT-IR spectrometry.

  7. Nickel nanoparticle decorated graphene for highly selective isolation of polyhistidine-tagged proteins

    NASA Astrophysics Data System (ADS)

    Liu, Jia-Wei; Yang, Ting; Ma, Lin-Yu; Chen, Xu-Wei; Wang, Jian-Hua

    2013-12-01

    Nickel nanoparticle decorated graphene (GP-Ni) is prepared by one-pot hydrothermal reduction of graphene oxide and nickel cations by hydrazine hydrate in the presence of poly(sodium-p-styrenesulfonate) (PSS). The GP-Ni hybrid is characterized by XRD, TEM, SEM, XPS, Raman and FT-IR spectra, demonstrating the formation of poly-dispersed nickel nanoparticles with an average size of 83 nm attached on the surface of graphene sheets. The GP-Ni hybrid exhibits ferromagnetic behavior with a magnetization saturation of 31.1 emu g-1 at 10 000 Oersted (Oe). The GP-Ni also possesses favorable stability in aqueous medium and rapid magnetic response to an external magnetic field. These make it a novel magnetic adsorbent for the separation/isolation of His6-tagged recombinant proteins from a complex sample matrix (cell lysate). The targeted protein species is captured onto the surface of the GP-Ni hybrid via specific metal affinity force between polyhistidine groups and nickel nanoparticles. The SDS-PAGE assay indicates highly selective separation of His6-tagged Smt A from cell lysate. The GP-Ni hybrid displays favorable performance on the separation/isolation of His6-tagged recombinant proteins with respect to the commercial NTA-Ni2+ column.

  8. Conformations of 1-heptene secondary ozonide as studied by low temperature FT-IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Bariseviciute, R.; Ceponkus, J.; Sablinskas, V.; Kimtys, L.

    2007-11-01

    Conformational diversity of the 1-heptene secondary ozonides (SOZ) in solid neat films as well as isolated in Ar or CO 2 matrices was studied by the means of FT-IR absorption spectroscopy. The ozonization reaction was performed at 77 K in the neat films of the reactants. The spectra of the ozonide were analyzed by combining the experimental data with the results of theoretical calculations performed at B3LYP 6-311++G (3df, 3pd) level. It was found that the samples of 1-heptene secondary ozonide exist as a mixture of three dominating conformers. The most stable conformer is the one with O-O half-chair configuration of the five membered ring, the aliphatic radical attached to the ring in equatorial position and the aliphatic chain being in gauche (∠OCCC ≈ -60°) position. The other two stable conformers are equatorial with aliphatic chain in anti (∠OCCC ≈ 180°) and gauche (∠OCCC ≈ 60°) positions. It was found from Van't Hoff plots that Δ H of the equatorial anti conformer is equal to 0.24 ± 0.03 kJ/mol. The experimental value of Δ H is in reasonable accordance to the calculated one - 0.5 kJ/mol.

  9. Ceramic Matrix Composites Performances Under High Gamma Radiation Doses

    NASA Astrophysics Data System (ADS)

    Cemmi, A.; Baccaro, S.; Fiore, S.; Gislon, P.; Serra, E.; Fassina, S.; Ferrari, E.; Ghisolfi, E.

    2014-06-01

    Ceramic matrix composites reinforced by continuous ceramic fibers (CMCs) represent a class of advanced materials developed for applications in automotive, aerospace, nuclear fusion reactors and in other specific systems for harsh environments. In the present work, the silicon carbide/silicon carbide (SiCf/SiC) composites, manufactured by Chemical Vapour Infiltration process at FN S.p.A. plant, have been evaluated in term of gamma radiation hardness at three different absorbed doses (up to around 3MGy). Samples behavior has been investigated before and after irradiation by means of mechanical tests (flexural strength) and by surface and structural analyses (X-ray diffraction, SEM, FTIR-ATR, EPR).

  10. Chiral fiber optical isolator

    NASA Astrophysics Data System (ADS)

    Kopp, Victor I.; Zhang, Guoyin; Zhang, Sheng; Genack, Azriel Z.; Neugroschl, Dan

    2009-02-01

    We propose an in-fiber chiral optical isolator based on chiral fiber polarizer technology and calculate its performance by incorporating the magnetic field into the scattering matrix. The design will be implemented in a special preform, which is passed through a miniature heat zone as it is drawn and twisted. The birefringence of the fiber is controlled by adjusted the diameter of a dual-core optical fiber. By adjusting the twist, the fiber can convert linear to circular polarization and reject one component of circular polarization. In the novel central portion of the isolator, the fiber diameter is large. The effective birefringence of the circular central core with high Verdet constant embedded in an outer core of slightly smaller index of refraction is small. The central potion is a non-reciprocal polarization converter which passes forward traveling left circularly polarized (LCP) light as LCP, while converting backward propagating LCP to right circularly polarized (RCP) light. Both polarizations of light traveling backwards are scattered out of the isolator. Since it is an all-glass structure, we anticipate that the isolator will be able to handle several watts of power and will be environmentally robust.

  11. Combined SIMS, NanoSIMS, FTIR, and SEM Studies of OH in Nominally Anhydrous Minerals (NAMs)

    NASA Astrophysics Data System (ADS)

    Mosenfelder, J. L.; Le Voyer, M.; Rossman, G. R.; Guan, Y.; Bell, D. R.; Asimow, P. D.; Eiler, J.

    2010-12-01

    The accurate analysis of trace concentrations of hydrogen in NAMs is a long-standing problem, with wide-ranging implications in geology and planetology. SIMS and FTIR are two powerful and complementary analytical tools capable of measuring concentrations down to levels of less than 1 ppm H2O. Both methods, however, are subject to matrix effects and rely on other techniques such as manometry or nuclear reaction analysis (NRA) for quantitative calibration. We compared FTIR and SIMS data for a wide variety of NAMs: olivine, orthopyroxene, clinopyroxene, pyrope and grossular garnet, rutile, zircon, kyanite, andalusite, and sillimanite. Some samples were also characterized using high-resolution FE-SEM to assess the potential contribution of submicrocopic inclusions to the analyses. For SIMS, we use high mass resolution (≥5000 MRP) to measure 16O1H, using 30Si and/or 18O as reference isotopes. We use both primary standards, measured independently using manometry or NRA (e.g., [1]), and secondary standards, measured using polarized FTIR referenced back to calibrations developed on primary standards. Our major focus was on on olivine, for which we collected repeated calibration data with both SIMS and NanoSIMS, bracketing measurements of H diffusion profiles in both natural and experimentally annealed crystals at levels of 5-100 ppm H2O. With both instruments we establish low blanks (≤5 ppm) and high precision (typically less than 5% 2-σ errors in 16O1H/30Si), critical requirements for the low concentration levels being measured. Assessment of over 300 analyses on 11 olivines allows us to evaluate the suitability of different standards, several of which are in use in other laboratories [2,3,4]. Seven olivines, with 0-125 ppm H2O, give highly reproducible results and allow us to establish well-constrained calibration slopes with high correlation coefficients (r2 = 0.98-99), in contrast to previous studies [2,3,4]. However, four kimberlitic megacrysts with 140-243 ppm H

  12. Model study by FT-IR of the interaction of select cholate dissolution inhibitors with poly(norbornene-alt-maleic anhydride) and its derivatives

    NASA Astrophysics Data System (ADS)

    Dabbagh, Gary; Houlihan, Francis M.; Rushkin, Ilya; Hutton, Richard S.; Nalamasu, Omkaram; Reichmanis, Elsa; Gabor, Allen H.; Medina, Arturo N.

    1999-06-01

    The fundamental nature of the interaction between the polymer matrix and the cholate based dissolution inhibitors are being studied by Fourier Transform-IR (FTIR) spectroscopy. It was found that the simple cholate derivatives undergo, in a blend with poly(norbornene-alt- maleic anhydride) and in a blend with the terpolymers poly(norbornene-alt-maleic anhydride-co-t-butylacrylate) and poly(norbornene-alt-maleic anhydride-co-acrylic acid), stronger interaction as seen by shifts in the OH region of the spectra than do blends with dimeric or oligomeric cholates.

  13. Diffuse reflectance FTIR of stains on grit blasted metals

    SciTech Connect

    Powell, G.L.; Hallman, R.L. Jr.; Cox, R.L.

    1997-08-09

    Diffuse reflectance mid-infrared Fourier transform (DRIFT) spectroscopy has been applied to the detection of oil contamination on grit-blasted metals. The object of this application is to detect and discriminate between silicone and hydrocarbon oil contamination at levels approaching 10 mg/m{sup 2}. A portable FTIR spectrometer with dedicated diffuse reflectance optics was developed for this purpose. Using translation devices positioned by instructions from the spectrometer operating system, images of macroscopic substrates were produced with millimeter spatial resolution. The pixels that comprise an image are each a full mid-infrared spectrum with excellent signal-to-noise, each determined as individual files and uniquely saved to disc. Reduced spectra amplitudes, based on peak height, area, or other chemometric techniques, mapped as a function of the spatial coordinates of the pixel are used to display the image. This paper demonstrates the application of the technique to the analysis of stains on grit-blasted metals, including the calibration of the method, the inspection of substrates, and the migration of oil contamination.

  14. 3-Iodobenzaldehyde: XRD, FT-IR, Raman and DFT studies.

    PubMed

    Kumar, Chandraju Sadolalu Chidan; Parlak, Cemal; Tursun, Mahir; Fun, Hoong-Kun; Rhyman, Lydia; Ramasami, Ponnadurai; Alswaidan, Ibrahim A; Keşan, Gürkan; Chandraju, Siddegowda; Quah, Ching Kheng

    2015-06-15

    The structure of 3-iodobenzaldehyde (3IB) was characterized by FT-IR, Raman and single-crystal X-ray diffraction techniques. The conformational isomers, optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of 3IB were examined using density functional theory (DFT) method, with the Becke-3-Lee-Yang-Parr (B3LYP) functional and the 6-311+G(3df,p) basis set for all atoms except for iodine. The LANL2DZ effective core basis set was used for iodine. Potential energy distribution (PED) analysis of normal modes was performed to identify characteristic frequencies. 3IB crystallizes in monoclinic space group P21/c with the O-trans form. There is a good agreement between the theoretically predicted structural parameters, and vibrational frequencies and those obtained experimentally. In order to understand halogen effect, 3-halogenobenzaldehyde [XC6H4CHO; X=F, Cl and Br] was also studied theoretically. The free energy difference between the isomers is small but the rotational barrier is about 8kcal/mol. An atypical behavior of fluorine affecting conformational preference is observed. PMID:25767992

  15. 3-Iodobenzaldehyde: XRD, FT-IR, Raman and DFT studies

    NASA Astrophysics Data System (ADS)

    Kumar, Chandraju Sadolalu Chidan; Parlak, Cemal; Tursun, Mahir; Fun, Hoong-Kun; Rhyman, Lydia; Ramasami, Ponnadurai; Alswaidan, Ibrahim A.; Keşan, Gürkan; Chandraju, Siddegowda; Quah, Ching Kheng

    2015-06-01

    The structure of 3-iodobenzaldehyde (3IB) was characterized by FT-IR, Raman and single-crystal X-ray diffraction techniques. The conformational isomers, optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of 3IB were examined using density functional theory (DFT) method, with the Becke-3-Lee-Yang-Parr (B3LYP) functional and the 6-311+G(3df,p) basis set for all atoms except for iodine. The LANL2DZ effective core basis set was used for iodine. Potential energy distribution (PED) analysis of normal modes was performed to identify characteristic frequencies. 3IB crystallizes in monoclinic space group P21/c with the O-trans form. There is a good agreement between the theoretically predicted structural parameters, and vibrational frequencies and those obtained experimentally. In order to understand halogen effect, 3-halogenobenzaldehyde [XC6H4CHO; X = F, Cl and Br] was also studied theoretically. The free energy difference between the isomers is small but the rotational barrier is about 8 kcal/mol. An atypical behavior of fluorine affecting conformational preference is observed.

  16. FTIR measurements of thermal infrared sky radiance and transmission

    SciTech Connect

    Bennett, C.L.

    1994-07-01

    Precise relative measurements of sky continuum and line emission and absorption have been made using FTIR spectroscopy. During conditions of horizontally uniform air composition, measurements of the variation of the spectral radiance with elevation angle sample an air column that varies simply as the cosecant of the elevation angle. In spectral regions that are optically thin, an extrapolation to zero air mass can be used to accurately determine instrumental background. An ambient temperature black body reference furnishes an accurate measurement of the instrumental spectral response. The excess sky emission above instrumental background relative to the local black body reference spectrum thus provides a calibrated sky radiance spectrum. This spectrum can be used to calculate the atmospheric transmission. As a test, transmission spectra have been directly obtained with the full moon as a backlighting source, and are in excellent agreement with the sky radiance derived transmission spectra. For spectral regions dominated by water, the continuum emission has been measured for paths involving the entire atmospheric column. Reasonable agreement with previous laboratory measurement of the continuum strength is obtained.

  17. FTIR spectroscopy of the M photointermediate in pharaonis rhoborhodopsin.

    PubMed Central

    Furutani, Yuji; Iwamoto, Masayuki; Shimono, Kazumi; Kamo, Naoki; Kandori, Hideki

    2002-01-01

    pharaonis phoborhodopsin (ppR; also called pharaonis sensory rhodopsin II, psR-II) is a photoreceptor for negative phototaxis in Natronobacterium pharaonis. During the photocycle of ppR, the Schiff base of the retinal chromophore is deprotonated upon formation of the M intermediate (ppR(M)). The present FTIR spectroscopy of ppR(M) revealed that the Schiff base proton is transferred to Asp-75, which corresponds to Asp-85 in a light-driven proton-pump bacteriorhodopsin (BR). In addition, the C==O stretching vibrations of Asn-105 were assigned for ppR and ppR(M). The common hydrogen-bonding alterations in Asn-105 of ppR and Asp-115 of BR were found in the process from photoisomerization (K intermediate) to the primary proton transfer (M intermediate). These results implicate similar protein structural changes between ppR and BR. However, BR(M) decays to BR(N) accompanying a proton transfer from Asp-96 to the Schiff base and largely changed protein structure. In the D96N mutant protein of BR that lacks a proton donor to the Schiff base, the N-like protein structure was observed with the deprotonated Schiff base (called M(N)) at alkaline pH. In ppR, such an N-like (M(N)-like) structure was not observed at alkaline pH, suggesting that the protein structure of the M state activates its transducer protein. PMID:12496114

  18. Analyzing peat pyrolysis by in-situ FTIR

    SciTech Connect

    Fen, J.; Li, W.Y.; Li, F.; Xie, K.C.

    1997-12-31

    Coal pyrolysis is complex process that includes many small reactions. Being complicated, it is difficult to study the pyrolysis mechanism with high rank coal directly. Peat is a rudimentary coal which has the most simple structure with lower polymerization. Some researchers think that the key to understanding coal structure is in an appreciation of the molecular components of the original peat swamp and how these might be modified. It is generally agreed that the chemical diversity of various coals will affect rate of coal combustion through the devolatilization process. Upon heating, some of the chemical bonds in coal undergo cracking and result in the release of light gases and the production of tar. Through analysis of peat which is best model compound of coal, some basic step reactions of coal can be understood. The objective of this study is to analyze peat pyrolysis using a in-situ pyrolysis-FTIR and to establish the pyrolysis model. The results show that during rapid peat pyrolysis, all the functional groups produced have almost the same activity energy; the difference among them is the degree of reaction.

  19. Fourier transform infrared spectroscopy (FTIR) of laser-irradiated cementum

    NASA Astrophysics Data System (ADS)

    Rechmann, Peter; White, Joel M.; Cecchini, Silvia C. M.; Hennig, Thomas

    2003-06-01

    Utilizing Fourier Transform Infrared Spectroscopy (FTIR) in specular reflectance mode chemical changes of root cement surfaces due to laser radiation were investigated. A total of 18 samples of root cement were analyzed, six served as controls. In this study laser energies were set to those known for removal of calculus or for disinfection of periodontal pockets. Major changes in organic as well as inorganic components of the cementum were observed following Nd:YAG laser irradiation (wavelength 1064 nm, pulse duration 250 μs, free running, pulse repetition rate 20 Hz, fiber diameter 320 μm, contact mode; Iskra Twinlight, Fontona, Slovenia). Er:YAG laser irradiation (wavelength 2.94 μm, pulse duration 250 μs, free running, pulse repetition rate 6 Hz, focus diameter 620 μm, air water cooling 30 ml/min; Iskra Twinlight, Fontona, Slovenia) significantly reduced the Amid bands due to changes in the organic components. After irradiation with a frequency doubled Alexandrite laser (wavelength 377 nm, pulse duration 200 ns, q-switched, pulse repetition rate 20 Hz, beam diameter 800 μm, contact mode, water cooling 30 ml/min; laboratory prototype) only minimal reductions in the peak intensity of the Amide-II band were detected.

  20. FTIR Analysis of Functional Groups in Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Shokri, S. M.; McKenzie, G.; Dransfield, T. J.

    2012-12-01

    Secondary organic aerosols (SOA) are suspensions of particulate matter composed of compounds formed from chemical reactions of organic species in the atmosphere. Atmospheric particulate matter can have impacts on climate, the environment and human health. Standardized techniques to analyze the characteristics and composition of complex secondary organic aerosols are necessary to further investigate the formation of SOA and provide a better understanding of the reaction pathways of organic species in the atmosphere. While Aerosol Mass Spectrometry (AMS) can provide detailed information about the elemental composition of a sample, it reveals little about the chemical moieties which make up the particles. This work probes aerosol particles deposited on Teflon filters using FTIR, based on the protocols of Russell, et al. (Journal of Geophysical Research - Atmospheres, 114, 2009) and the spectral fitting algorithm of Takahama, et al (submitted, 2012). To validate the necessary calibration curves for the analysis of complex samples, primary aerosols of key compounds (e.g., citric acid, ammonium sulfate, sodium benzoate) were generated, and the accumulated masses of the aerosol samples were related to their IR absorption intensity. These validated calibration curves were then used to classify and quantify functional groups in SOA samples generated in chamber studies by MIT's Kroll group. The fitting algorithm currently quantifies the following functionalities: alcohols, alkanes, alkenes, amines, aromatics, carbonyls and carboxylic acids.

  1. Hydrogen-Deuterium exchange monitored by ATR-FTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Poe, Brent; Del Vecchio, Alessandro; Cestelli Guidi, Mariangela

    2016-04-01

    Measuring the extent of isotopic exchange is a common means for the determination of self-diffusion coefficients in any type of medium (gas, liquid, amorphous solid, crystalline solid). For rapidly diffusing species such as hydrogen in condensed phases, real time methods involving vibrational spectroscopy can be used by taking advantage of the large relative mass difference between 1H and 2H, resulting in large differences in the band positions of their vibrational modes. We demonstrate rapid isotopic exchange between D2O liquid and H2O vapor using ATR (attenuated total reflectance) in a FTIR spectrometer. Over the course of a few minutes several spectra were acquired of a D2O droplet mounted on a diamond crystal. The progressive exchange reaction between the liquid phase and H2O from the atmosphere was monitored by measuring the decreasing absorbance of the D-O-D bending and O-D stretching bands and the increasing absorbance of the D-O-H and H-O-H bending and O-H stretching bands as functions of time. Our results offer some intriguing insights into the structural characteristics of water as inferred by this exchange process.

  2. FTIR, Raman spectra and ab initio calculations of 2-mercaptobenzothiazole.

    PubMed

    Rai, Amareshwar K; Singh, Rachana; Singh, K N; Singh, V B

    2006-02-01

    FTIR and Raman spectra of a rubber vulcanization accelerator, 2-mercaptobenzothiazole (MBT), were recorded in the solid phase. The harmonic vibrational wavenumbers, for both the toutomeric forms of MBT, as well as for its dimeric complex, have been calculated, using ab initio RHF and density functional B3LYP methods invoking different basis sets upto RHF/6-31G** and B3LYP/6-31G** and the results were compared with the experimental values. Conformational studies have been also carried out regarding its toutomeric monomer forms and its dimer form. With all the basis sets the thione form of MBT (II) is predicted to be more stable than thiol form (I) and dimeric conformation (III) is predicted to be more stable with monomeric conformations (I) and (II). Vibrational assignments have been made, and it has been found that the calculated normal mode frequencies of dimeric conformation (III) are required for the analysis of IR and Raman bands of the MBT. The predicted shift in NH- stretching vibration towards the lower wave number side with the B3LYP/6-31G** calculations for the most stable dimer form (III), is in better agreement with experimental results. The intermolecular sulfur-nitrogen distance in N-H...S hydrogen bond was found to be 3.35 angstroms from these calculations, is also in agreement to the experimental value. PMID:16098806

  3. FT-IR Microspectroscopy on molecular building of Zebrafish oocytes

    NASA Astrophysics Data System (ADS)

    Carnevali, Oliana; Conti, Carla; Ferraris, Paolo; Garavaglia, Maria Grazia; Gioacchini, Giorgia; Giorgini, Elisabetta; Rubini, Corrado; Sabbatini, Simona; Tosi, Giorgio

    2009-12-01

    Zebrafish oocytes growth causes relevant modifications in protein components; in fact, the proteolytic cleavage of vitellogenin, a large sex-specific phospholipoglycoprotein synthesized in the female liver, leads to three main yolk protein components (phosphovitin and lipovitellins 1, 2), present as a complex in the oocyte. FT-IR Microspectroscopy could have the potentiality of monitoring these biochemical changes during the maturation process. Representative spectra for I-II, IIIA, IIIB and IV classes oocytes (Hierarchical Clustering Analysis and Principal Component Analysis) were investigated to find specific vibrational patterns corresponding to different maturation degrees. On going from I-II to IV class oocytes, relevant spectral differences were found with III class exhibiting an intermediate spectroscopic behaviour. In particular, the increase of the convoluted band at 2925 cm -1 (CH 2 and CH 3 stretching modes), as well as of intensity band ratios at 2926/2954 cm -1 ( νasym CH 2/CH 3), 2854/2873 cm -1 ( νsym CH 2/CH 3) and 1452/1392 cm -1 ( δCH/νCOO), suggest longer lipidic chains; broadening of Amide I and II bands and absorptions at 1737 ( νC dbnd O, phospholipids) and 1157 cm -1 ( νC sbnd O and νC sbnd OH carbohydrates) in lipovitellin and vitellogenin spectra, are present in III and IV classes.

  4. Synchrotron-FTIR microspectroscopy enables the distinction of lipid accumulation in thraustochytrid strains through analysis of individual live cells.

    PubMed

    Vongsvivut, Jitraporn; Heraud, Philip; Gupta, Adarsha; Thyagarajan, Tamilselvi; Puri, Munish; McNaughton, Don; Barrow, Colin J

    2015-02-01

    The superior characteristics of high photon flux and diffraction-limited spatial resolution achieved by synchrotron-FTIR microspectroscopy allowed molecular characterization of individual live thraustochytrids. Principal component analysis revealed distinct separation of the single live cell spectra into their corresponding strains, comprised of new Australasian thraustochytrids (AMCQS5-5 and S7) and standard cultures (AH-2 and S31). Unsupervised hierarchical cluster analysis (UHCA) indicated close similarities between S7 and AH-7 strains, with AMCQS5-5 being distinctly different. UHCA correlation conformed well to the fatty acid profiles, indicating the type of fatty acids as a critical factor in chemotaxonomic discrimination of these thraustochytrids and also revealing the distinctively high polyunsaturated fatty acid content as key identity of AMCQS5-5. Partial least squares discriminant analysis using cross-validation approach between two replicate datasets was demonstrated to be a powerful classification method leading to models of high robustness and 100% predictive accuracy for strain identification. The results emphasized the exceptional S-FTIR capability to perform real-time in vivo measurement of single live cells directly within their original medium, providing unique information on cell variability among the population of each isolate and evidence of spontaneous lipid peroxidation that could lead to deeper understanding of lipid production and oxidation in thraustochytrids for single-cell oil development. PMID:25594491

  5. Tendon Functional Extracellular Matrix

    PubMed Central

    Screen, H.R.C.; Birk, D.E.; Kadler, K.E.; Ramirez, F; Young, M.F.

    2015-01-01

    This article is one of a series, summarising views expressed at the Orthopaedic Research Society New Frontiers in Tendon Research Conference. This particular article reviews the three workshops held under the “Functional Extracellular Matrix” stream. The workshops focused on the roles of the tendon extracellular matrix, such as performing the mechanical functions of tendon, creating the local cell environment and providing cellular cues. Tendon is a complex network of matrix and cells, and its biological functions are influenced by widely-varying extrinsic and intrinsic factors such as age, nutrition, exercise levels and biomechanics. Consequently, tendon adapts dynamically during development, ageing and injury. The workshop discussions identified research directions associated with understanding cell-matrix interactions to be of prime importance for developing novel strategies to target tendon healing or repair. PMID:25640030

  6. Matrix interdiction problem

    SciTech Connect

    Pan, Feng; Kasiviswanathan, Shiva

    2010-01-01

    In the matrix interdiction problem, a real-valued matrix and an integer k is given. The objective is to remove k columns such that the sum over all rows of the maximum entry in each row is minimized. This combinatorial problem is closely related to bipartite network interdiction problem which can be applied to prioritize the border checkpoints in order to minimize the probability that an adversary can successfully cross the border. After introducing the matrix interdiction problem, we will prove the problem is NP-hard, and even NP-hard to approximate with an additive n{gamma} factor for a fixed constant {gamma}. We also present an algorithm for this problem that achieves a factor of (n-k) mUltiplicative approximation ratio.

  7. Albizia procera gum as an excipient for oral controlled release matrix tablet.

    PubMed

    Pachuau, Lalduhsanga; Mazumder, Bhaskar

    2012-09-01

    The purpose of this research was to develop and evaluate controlled release matrix tablets of paracetamol based on natural gum exudates of Albizia procera. Procera gum was characterized of its properties like compressibility index, angle of repose, viscosity and moisture content. The interaction between the gum and paracetamol was also studied through differential scanning calorimetry (DSC) and FTIR spectroscopy. Matrix tablets were then prepared by wet granulation method with different concentrations of procera gum and hydroxypropyl methylcellulose (HPMC) and evaluated for their physical properties like weight variation, hardness, friability and content uniformity. Dissolution study was conducted to characterize release mechanism from the matrix system and data were fitted to various kinetic models. The mechanism of drug release from both types of matrix tablets was found to be anomalous type. Results from various evaluations suggested that A. procera gum could be used as drug release retardant in controlled release matrix systems. PMID:24751043

  8. Semi-quantitative analysis of FT-IR spectra of humic fractions of nine US soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fourier Transform Infrared Spectroscopy (FT-IR) is a simple and fast tool for characterizing soil organic matter. However, most FT-IR spectra are only analyzed qualitatively. In this work, we prepared mobile humic acid (MHA) and recalcitrant calcium humate (CaHA) from nine soils collected from six ...

  9. 34 GHz EPR FTIR spectra of chromatographically separated Boscan asphaltene fractions

    SciTech Connect

    Malhotra, V.M. ); Buckmaster, H.A. )

    1989-03-01

    The authors report on their re-examination of the 34 GHz and Fourier transform infrared (FTIR) measurements on three fractions of Boxcan asphaltene separated by the gel permeation chromatography (GPC) technique. The authors attempted to determine various types of vanadium coordination in GPC fractions by their partial combustion and subsequent EPR AND FTIR measurements.

  10. ATR-FTIR Spectroscopy in the Undergraduate Chemistry Laboratory: Part I--Fundamentals and Examples

    ERIC Educational Resources Information Center

    Schuttlefield, Jennifer D.; Grassian, Vicki H.

    2008-01-01

    Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy is a useful technique for measuring the infrared spectra of solids and liquids as well as probing adsorption on particle surfaces. Several examples of the use of FTIR-ATR spectroscopy in different undergraduate chemistry laboratory courses are presented here. These…

  11. Comparison of biochar formation from various agricultural by-products using FTIR spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar is charred material produced by the pyrolysis of organic biomass. In this work, Fourier transform infrared (FTIR) spectra of different agricultural by-products feedstock and their derived biochars were collected to explore the potential of FTIR technique as a simple and rapid method for char...

  12. Phosphorus Features in FT-IR Spectra of Natural Organic Matter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fourier-Transform Infrared (FT-IR) spectroscopy has been used extensively to characterize natural organic matter (NOM). Absorption bands at 1100-1000 cm-1 in FT-IR spectra of NOM have been frequently assigned to alcoholic and polysaccharide C-O stretching or to vibrations of SiO2-related impurities...

  13. FTIR SOLUTION SPECTRA OF PROPYL SULFIDE, PROPYL SULFOXIDE, AND PROPYL SULFONE

    EPA Science Inventory

    FTIR spectra were obtained of 0.5% volumetric solutions of propyl sulfide, propyl sulfoxide and propyl sulfone in hexane, CC14, CS2, and CHCl3 to assist in the assignment of FTIR-PAS spectra of propyl sulfoxide sorbed within the structure of several peats and onto cellulose. he C...

  14. A chemometric method for correcting FTIR spectra of biomaterials for interference from water in KBr discs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    FTIR analysis of solid biomaterials by the familiar KBr disc technique is very often frustrated by water interference in the important protein (amide I) and carbohydrate (hydroxyl) regions of their spectra. A method was therefore devised that overcomes the difficulty and measures FTIR spectra of so...

  15. Complex matrix model duality

    SciTech Connect

    Brown, T. W.

    2011-04-15

    The same complex matrix model calculates both tachyon scattering for the c=1 noncritical string at the self-dual radius and certain correlation functions of operators which preserve half the supersymmetry in N=4 super-Yang-Mills theory. It is dual to another complex matrix model where the couplings of the first model are encoded in the Kontsevich-like variables of the second. The duality between the theories is mirrored by the duality of their Feynman diagrams. Analogously to the Hermitian Kontsevich-Penner model, the correlation functions of the second model can be written as sums over discrete points in subspaces of the moduli space of punctured Riemann surfaces.

  16. FTIR spectroscopy and scanning electron microscopic analysis of pretreated biosorbent to observe the effect on Cr (VI) remediation.

    PubMed

    Kiran, Bala; Rani, Nisha; Kaushik, Anubha

    2016-11-01

    Various chemical and physical treatments have been applied to indigenously isolated cyanobacterial strain, Lyngbya putealis HH-15, to observe the effect on chromium removal capacity. Pretreatment with hydrochloric acid (99.1%) and nitric acid (98.5%) resulted in enhanced chromium removal as compared to untreated control biosorbent (98.1%). Pretreatment with acetic acid (97.9%), methanol (97.0%), calcium chloride (96.0%), hot water (95.2%), and sodium hydroxide (93.9%) did not improve the chromium removal capacity of biosorbent. Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM) analysis identified changes in biomass functionality and availability after physical and chemical modification-the results of which were in agreement with metal removal studies. In conclusion, this acid-treated biosorbent represents a suitable candidate to replace conventional removal technologies for metal-bearing wastewaters. PMID:27185214

  17. Study of the formation of carbonyl compounds in edible oils and fats by 1H-NMR and FTIR

    NASA Astrophysics Data System (ADS)

    Moya Moreno, M. C. M.; Mendoza Olivares, D.; Amézquita López, F. J.; Peris Martínez, V.; Bosch Reig, F.

    1999-05-01

    Oils and fats start decomposing from the moment they are isolated from their natural environment. Heating accelerates oxidative rancidity and frying at high temperatures produces thermal degradation with the formation of decomposition products, such as aldehydes, ketones, free acids and hydroxilic compounds that in high levels can be harmful to human health. The decomposition products formed up to 300°C were determined by means of 1H-NMR spectroscopy and an FTIR spectroscopic method was developed for the quantification of carbonyl compounds generated during heating. The results show that there is a formation of carbonyl compounds starting at 150°C and when the sample was heated at 300°C for 40 min, the following contents (expressed as butyraldehyde mass fraction) were found: olive oil 10.5%, sunflower oil 11.3%, corn oil 3.0%, seeds oil (sunflower, safflower and canola seed) 6.6% and lard 3.5%.

  18. Matrixed business support comparison study.

    SciTech Connect

    Parsons, Josh D.

    2004-11-01

    The Matrixed Business Support Comparison Study reviewed the current matrixed Chief Financial Officer (CFO) division staff models at Sandia National Laboratories. There were two primary drivers of this analysis: (1) the increasing number of financial staff matrixed to mission customers and (2) the desire to further understand the matrix process and the opportunities and challenges it creates.

  19. FTIR characterization of thermally cycled PMR-15 composites

    NASA Technical Reports Server (NTRS)

    Young, Philip R.; Chang, A. C.

    1988-01-01

    Chemical characterization results are presented for a variety of PMR-15/graphite composites, differentiated according to prepreg types and cure cycles, which were subjected to 1000 thermal cycles between 0 and 450 F. Fourier transform IR spectroscopy was used in conjunction with diffuse reflectance sampling to examine whether changes in the matrix resin chemistry due to environmental exposure may have contributed to microcracking. Analysis based on compound spectra revealed behavior associated with the oxidation of methylene groups to carbonyl groups on the composite surface; evidence of crosslinking also emerged, although the two phenomena do not appear to be related.

  20. New insight into chemical changes of dissolved organic matter during anaerobic digestion of dewatered sewage sludge using EEM-PARAFAC and two-dimensional FTIR correlation spectroscopy.

    PubMed

    Li, Xiaowei; Dai, Xiaohu; Takahashi, Junichi; Li, Ning; Jin, Jingwei; Dai, Lingling; Dong, Bin

    2014-05-01

    Dissolved organic matter (DOM) is a key component in reaction network of anaerobic digestion. In this study, fluorescent excitation-emission matrix-parallel factor (EEM-PARAFAC) analysis and two-dimensional (2D) FTIR correlation spectroscopy were firstly used to explore chemical changes of soluble intermediates in high-solid biogas reactor. EEM-PARAFAC showed that fluorescent components (tyrosine-like, tryptophan-like and humic-like groups) in DOM over time increased gradually, implying that these groups were reluctant to biodegrade (acidogenesis). The resistance to biodegradation presented the following order: humic-like group>tyrosine-like group>tryptophan-like group. 2D FTIR correlation spectroscopy indicated that the DOM change sequence with time followed the order: protein-like groups>structural carbohydrates and carboxylic acids>polysaccharides-like groups. Fluorescence intensities from EEM-PARAFAC and main bands of FTIR spectra correlated significantly with other chemical parameters, e.g. biogas production and dissolved organic carbon content. These findings supply novel realization for degradation degree and order of individual DOMs during anaerobic digestion for dewatered sewage sludge. PMID:24681632

  1. Infrared spectroscopic observation of the stabilized intermediate complex FO{sub 3} formed by reaction of mobile fluorine atoms with ozone molecules trapped in an argon matrix

    SciTech Connect

    Misochko, E.Y.; Akimov, A.V.; Wight, C.A.

    1999-10-07

    Chemical reaction of F atoms with O{sub 3} molecules in a solid argon matrix was studied with FTIR spectroscopy. Fluorine atoms were generated by UV photolysis of F{sub 2} molecules in dilute solutions of F{sub 2} and O{sub 3} in solid argon. The FO-O{sub 2} complex is observed for the first time as an intermediate product by reaction of mobile F atoms with isolated ozone molecules. The observed complex is characterized by two intense absorption bands at 1522 and 968 cm{sup {minus}1}. Use of isotopic mixtures {sup 16}O/{sup 18}O provides strong evidence for assignment of these bands to the O-O stretch and F-O stretch fundamentals of the complex, which are red-shifted by 34 and 61 cm{sup {minus}1}, respectively, from the corresponding values for O{sub 2} and FO. Photolysis at 532 nm leads to decay of the FO-O{sub 2} complexes and to the appearance of isolated free FO radicals.

  2. Water in Tektites and Impact Glasses by FTIR Spectrometry

    NASA Astrophysics Data System (ADS)

    Beran, Anton; Koeberl, Christian

    1997-03-01

    To improve the scarce data base of water content in tektites and impact glasses, we analyzed 26 tektites from all four strewn fields and 25 impact glass samples for their water content. We used the fourier transformed IR (FTIR) spectrometry method, which permits measurement of areas of about 40 mm in diameter. Our results show that the tektites have water contents ranging from 0.002 to 0.030 wt% (average 0.014+/-0.008 wt%). Ivory Coast tektites have the lowest water abundances (0.002-0.003 wt%), and Muong Nong-type indochinites and some North American tektites having the highest contents (up to about 0.03 wt%). Impact glass samples (from the Zhamanshin, Aouelloul, and Rio Cuarto craters) yielded water contents of 0.008 to 0.13 wt% H2O. Typical impact glasses from the Aouelloul and Zhamanshin craters have low water contents (0.008 to 0.063 wt%). Libyan Desert Glasses and Rio Cuarto glasses have higher water contents (about 0.11 wt%). We also analyzed glasses of unknown origin (e.g., urengoites; glass fragments from Tikal), which showed very low water contents, in agreement with an origin by impact. Our data confirm that all tektites found on land have very low water contents (<0.03 wt% water), while impact glasses have slightly higher water contents. Both glass types are very dry compared to volcanic glasses. This study confirms that the low water contents (<0.05 wt%) of such glasses can be considered good evidence for an origin by impact.

  3. Investigating the microstructure of keratin extracted from wool: Peptide sequence (MALDI-TOF/TOF) and protein conformation (FTIR)

    NASA Astrophysics Data System (ADS)

    Cardamone, Jeanette M.

    2010-04-01

    Investigations of keratins extracted from wool by reduction hydrolysis and by alkaline hydrolysis showed that their chemical compositions and secondary structures were similar to original wool. The keratin isolates were similar in amino acid, Amides I and II, and secondary structure to each other and to original wool. From SDS-PAGE electrophoresis, keratin isolated by reduction contained protein homologs of molecular weight, ˜40-60 kDa and keratin isolate from alkaline hydrolysis contained peptide fragments of ˜6-8 kDa. MALDI-TOF/TOF spectrometry confirmed that the reduction isolate contained Type II microfibrillar component 7C, hair Type II intermediate filament, Type I microfibrillar 48 kDa component 8C-1, and Type I microfibrillar 47.6 kDa protein homologs which contained alanine, glutamine, glutamic acid, leucine, serine, leucine, and cystine with highest amounts glutamic acid and leucine amino acids. FTIR spectroscopy was applied to examine secondary structure to confirm the content of α-helix/β-sheet/disordered regions for original wool (58.2%/37.9%/3.9%); keratin from reduction (36.7%/50.2%/13.1%); and keratin from alkaline hydrolysis (25.7%/51.8%/22.5%). The higher content of β-sheet secondary structure and intact α-helical conformation characterized these isolates as viable starting materials for chemical modification to form novel bio-based materials useful in industrial formulations and compositions. In particular keratin extracted by reduction with the molecular weight of original wool and the probability of useful mechanical properties can be transformed into stand-alone products of various shapes and forms such as porous foams, sponges, mats, and films for bio-based, adaptable structures.

  4. FTIR-I Compositional Mapping of the Cartilage-to-Bone Interface as a Function of Tissue Region and Age

    PubMed Central

    Khanarian, Nora T; Boushell, Margaret K; Spalazzi, Jeffrey P; Pleshko, Nancy; Boskey, Adele L; Lu, Helen H

    2016-01-01

    Soft tissue-to-bone transitions, such as the osteochondral interface, are complex junctions that connect multiple tissue types and are critical for musculoskeletal function. The osteochondral interface enables pressurization of articular cartilage, facilitates load transfer between cartilage and bone, and serves as a barrier between these two distinct tissues. Presently, there is a lack of quantitative understanding of the matrix and mineral distribution across this multitissue transition. Moreover, age-related changes at the interface with the onset of skeletal maturity are also not well understood. Therefore, the objective of this study is to characterize the cartilage-to-bone transition as a function of age, using Fourier transform infrared spectroscopic imaging (FTIR-I) analysis to map region-dependent changes in collagen, proteoglycan, and mineral distribution, as well as collagen organization. Both tissue-dependent and age-related changes were observed, underscoring the role of postnatal physiological loading in matrix remodeling. It was observed that the relative collagen content increased continuously from cartilage to bone, whereas proteoglycan peaked within the deep zone of cartilage. With age, collagen content across the interface increased, accompanied by a higher degree of collagen alignment in both the surface and deep zone cartilage. Interestingly, regardless of age, mineral content increased exponentially across the calcified cartilage interface. These observations reveal new insights into both region- and age-dependent changes across the cartilage-to-bone junction and will serve as critical benchmark parameters for current efforts in integrative cartilage repair. PMID:24839262

  5. Matrix Synthesis and Characterization

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The role of NASA in the area of composite material synthesis; evaluation techniques; prediction analysis techniques; solvent-resistant tough composite matrix; resistance to paint strippers; acceptable processing temperature and pressure for thermoplastics; and the role of computer modeling and fiber interface improvement were discussed.

  6. The Acrosomal Matrix.

    PubMed

    Foster, James A; Gerton, George L

    2016-01-01

    The acrosome, a single exocytotic vesicle on the head of sperm, has an essential role in fertilization, but the exact mechanisms by which it facilitates sperm-egg interactions remain unresolved. The acrosome contains dozens of secretory proteins that are packaged into the forming structure during spermatogenesis; many of these proteins are localized into specific topographical areas of the acrosome, while others are more diffusely distributed. Acrosomal proteins can also be biochemically classified as components of the acrosomal matrix, a large, relatively insoluble complex, or as soluble proteins. This review focuses on recent findings using genetically modified mice (gene knockouts and transgenic "green acrosome" mice) to study the effects of eliminating acrosomal matrix-associated proteins on sperm structure and function. Some gene knockouts produce infertile phenotypes with obviously missing, specific activities that affect acrosome biogenesis during spermatogenesis or interfere with acrosome function in mature sperm. Mutations that delete some components produce fertile phenotypes with subtler effects that provide useful insights into acrosomal matrix function in fertilization. In general, these studies enable the reassessment of paradigms to explain acrosome formation and function and provide novel, objective insights into the roles of acrosomal matrix proteins in fertilization. The use of genetically engineered mouse models has yielded new mechanistic information that complements recent, important in vivo imaging studies. PMID:27194348

  7. Matrix Embedded Organic Synthesis

    NASA Astrophysics Data System (ADS)

    Kamakolanu, U. G.; Freund, F. T.

    2016-05-01

    In the matrix of minerals such as olivine, a redox reaction of the low-z elements occurs. Oxygen is oxidized to the peroxy state while the low-Z-elements become chemically reduced. We assign them a formula [CxHyOzNiSj]n– and call them proto-organics.

  8. Constructing the matrix

    NASA Astrophysics Data System (ADS)

    Elliott, John

    2012-09-01

    As part of our 'toolkit' for analysing an extraterrestrial signal, the facility for calculating structural affinity to known phenomena must be part of our core capabilities. Without such a resource, we risk compromising our potential for detection and decipherment or at least causing significant delay in the process. To create such a repository for assessing structural affinity, all known systems (language parameters) need to be structurally analysed to 'place' their 'system' within a relational communication matrix. This will need to include all known variants of language structure, whether 'living' (in current use) or ancient; this must also include endeavours to incorporate yet undeciphered scripts and non-human communication, to provide as complete a picture as possible. In creating such a relational matrix, post-detection decipherment will be assisted by a structural 'map' that will have the potential for 'placing' an alien communication with its nearest known 'neighbour', to assist subsequent categorisation of basic parameters as a precursor to decipherment. 'Universal' attributes and behavioural characteristics of known communication structure will form a range of templates (Elliott, 2001 [1] and Elliott et al., 2002 [2]), to support and optimise our attempt at categorising and deciphering the content of an extraterrestrial signal. Detection of the hierarchical layers, which comprise intelligent, complex communication, will then form a matrix of calculations that will ultimately score affinity through a relational matrix of structural comparison. In this paper we develop the rationales and demonstrate functionality with initial test results.

  9. An Innovative Carbonate Fuel Cell Matrix, Abstract #188

    SciTech Connect

    Hilmi, Abdelkader; Surendranath, Arun; Yuh, Chao-Yi

    2015-05-28

    The electrolyte matrix in direct carbonate fuel cell (DFC) is a microporous ceramic structure sandwiched between the electrodes to isolate the fuel from the oxidant, store electrolyte and facilitate ionic transport. FCE has advanced DFC electrolyte matrix over the years and demonstrated that the matrix meets the requirements for greater than 5 year life based on accelerated tests and field stack operations. However, development of advanced designs and materials that can further increase the performance and extend cell life will enable accelerated MCFC deployment. This paper will report the progress on the development of an unique and innovative matrix design that offers numerous benefits to the carbonate fuel cell performance and durability. In addition, this paper will also review parameters that affect matrix material stability and approaches to extend cell life.

  10. Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbon Cations

    NASA Technical Reports Server (NTRS)

    Hudgins, D. M.; Allamandola, L. J.

    1995-01-01

    Gaseous, ionized polycyclic aromatic hydrocarbons (PAHs) are thought to be responsible for a very common family of interstellar infrared emission bands. Here the near- and mid-infrared spectra of the cations of the five most thermodynamically favored PAHs up to coronene: phenanthrene, pyrene, benzo(e)pyrene, benzo-(ghi)perylene, and coronene, are presented to test this hypothesis. For those molecules that have been studied previously (pyrene, pyrene-d(sub 10), and coronene), band positions and relative intensities are in agreement. In all of these cases we report additional features. Absolute integrated absorbance values are given for the phenanthrene, perdeuteriophenanthrene, pyrene, benzo(ghi]perylene, and coronene cations. With the exception of coronene, the cation bands corresponding to the CC modes are typically 2-5 times more intense than those of the CH out-of-plane bending vibrations. For the cations, the CC stretching and CH in-plane bending modes give rise to bands that are an order of magnitude stronger than those of the neutral species, and the CH out-of-plane bends produce bands that are 5-20 times weaker than those of the neutral species. This behavior is similar to that found in most other PAH cations studied to date. The astronomical implications of these PAH cation spectra are also discussed.

  11. Ultraviolet absorption and luminescence of matrix-isolated adenine

    SciTech Connect

    Polewski, K.; Sutherland, J.; Zinger, D.; Trunk, J.

    2011-10-01

    We have investigated the absorption, the fluorescence and phosphorescence emission and the fluorescence lifetimes of adenine in low-temperature argon and nitrogen matrices at 15 K. Compared to other environments the absorption spectrum shows higher intensity at the shortest wavelengths, and a weak apparent absorption peak is observed at 280 nm. The resolved fluorescence excitation spectrum has five peaks at positions corresponding to those observed in the absorption spectrum. The position of the fluorescence maximum depends on the excitation wavelength. Excitation below 220 nm displays a fluorescence maximum at 305 nm, while for excitations at higher wavelengths the maximum occurs at 335 nm. The results suggest that multiple-emission excited electronic states are populated in low-temperature gas matrices. Excitation at 265 nm produces a phosphorescence spectrum with a well-resolved vibrational structure and a maximum at 415 nm. The fluorescence decays corresponding to excitation at increasing energy of each resolved band could be fit with a double exponential, with the shorter and longer lifetimes ranging from 1.7 to 3.3 ns and from 12 to 23 ns, respectively. Only for the excitation at 180 nm one exponential is required, with the calculated lifetimes of 3.3 ns. The presented results provide an experimental evidence of the existence of multiple site-selected excited electronic states, and may help elucidate the possible deexcitation pathways of adenine. The additional application of synchrotron radiation proved to result in a significant enhancement of the resolution and spectral range of the phenomena under investigation.

  12. Characterization of PAH matrix with monazite stream containing uranium, gadolinium and iron

    NASA Astrophysics Data System (ADS)

    Pal, Sangita; Meena, Sher Singh; Goswami, D.

    2016-05-01

    Uranium (U) gadolinium(Gd) and iron (Fe) containing alkaline waste simulated effluent (relevant to alkaline effluent of monazite ore) has been treated with a novel amphoteric resin viz, Polyamidehydroxamate (PAH) containing amide and hydroxamic acid groups. The resin has been synthesized in an eco-friendly manner by polymerization nad conversion to functional groups characterized by FT-IR spectra and architectural overview by SEM. Coloration of the loaded matrix and de-coloration after extraction of uranium is the special characteristic of the matrix. Effluent streams have been analyzed by ICP-AES, U loaded PAH has been characterized by FT-IR, EXAFS, Gd and Fe by X-ray energy values of EDXRF at 6.053 Kev and 6.405 Kev respectively. The remarkable change has been observed in Mössbauer spectrum of Fe-loaded PAH samples.

  13. Ground-based FTIR measurements of Antarctic trace gases

    NASA Astrophysics Data System (ADS)

    Dybdahl, Arthur W.

    2001-06-01

    Ground-based long path FTIR hyper-resolution spectroscopy was employed to measure solar absorption spectra at Arrival Heights, Antarctica during nearly the entire 1998-1999 daylight season. The spectra were analyzed to retrieve vertical total column amounts and volume mixing ratio (VMR)profiles for each of five atmospheric trace gases: HCl, HF, CH4, N 2O and O3. HCl is a major reservoir for free atomic chlorine that directly destroys ozone within the Antarctic stratosphere. This was the first time that these gases were measured over such a long period of time in Antarctica, from just after seasonal sunrise to the approach of sunset. Two analytical tools were used to analyze the absorption microwindows cut from the spectra measured with the University of Denver instrument called SORTI: SFIT-1 that retrieved the vertical column amounts for each of the five trace gases, and SFIT-1-plus-PROFIT that in addition to retrieving the total column amounts for each gas, also retrieved vertical VMR profiles extending from the surface up to an altitude of 80 km. The column amounts and VMR's for each tract gas were assessed for temporal behavior throughout the daylight season. The seasonal losses of HCl due to heterogeneous chemistry were measured. The springtime depletion of ozone within the stratosphere was measured along with its subsequent recovery during the summer and autumn seasons. An extensive error analysis was conducted for each trace gas employing the measured random errors and systematic errors to obtain the relative uncertainty associated with each total column amount calculated. A correlation analysis was performed to determine the inter- relationships among eleven physical and dynamic parameters that included total column amounts for each trace gas, the temperature and height of the Antarctic tropopause, and the potential vorticity obtained for each of four stratospheric altitudes. Historical comparisons of the total column abundances measured during this study

  14. Photoluminescence, FTIR, and laser-Raman spectroscopic studies of PMN-PT containing iron

    NASA Astrophysics Data System (ADS)

    Bairavarasu, Sundar R.; Edwards, Matthew E.; Kukhtareva, Titania; Sastry, Medury D.; Lianos, Dimitrios; Kommidi, Praveena; Reddy, B. Rami; Janeisch, Holger M.; Aggarwal, Monmohan D.

    2007-09-01

    Lead magnesium niobate-lead titanate, Pb(Mg, Nb)O 3-PbTiO 3 is a piezoelectric, ferroelectric crystal at room temperature with large electromechanical coefficient. The crystals were grown by PbO-B IIO 3 flux method. Typically the crystals were colorless and transparent, but a small fraction of them were Brown/reddish colored and show interesting photoluminescence (PL) properties. The PL studies were conducted under XeCl (308nm) excitation and under Argon Ion (Ar +) laser excitation. The excitation with 308nm gave broad PL centered at 500nm and intense emission at 710nm. The emission at 710nm in colorless crystals is very weak. The excitation with Ar + laser coinciding with electronic absorption in brown samples gave rich and sharp PL particularly with 514.5 nm excitation. The PL with 514.5nm-Ar + laserexcitation, consisted of intense anti stokes emission in addition to intense red and near infrared emission, is a result of photo-transfer optically stimulated luminescence (PT-OSL). This involved electron-hole recombination at photoinduced magnetic polaron site. The PL emissions and the centers identified are the followings: 718nm emission due to magnetic polaron and 360nm emission due to cooperative emission from two polarons, Fe-R line at 660nm due to Fe 3+ coupled to a cation; 380nm and 399nm due to Pb 2+ clusters and Nb 5+ center; 630 and 860 nm due to 6p-->6s transition of Pb 3+ and 760nm due to isolated Fe 3+ ions. Raman spectrum of brown samples revealed the presence of nano particles/wires of orthorhombic β PbO. The FTIR spectrum gives evidence of significant amount of hydroxyl impurity.

  15. Paths correlation matrix.

    PubMed

    Qian, Weixian; Zhou, Xiaojun; Lu, Yingcheng; Xu, Jiang

    2015-09-15

    Both the Jones and Mueller matrices encounter difficulties when physically modeling mixed materials or rough surfaces due to the complexity of light-matter interactions. To address these issues, we derived a matrix called the paths correlation matrix (PCM), which is a probabilistic mixture of Jones matrices of every light propagation path. Because PCM is related to actual light propagation paths, it is well suited for physical modeling. Experiments were performed, and the reflection PCM of a mixture of polypropylene and graphite was measured. The PCM of the mixed sample was accurately decomposed into pure polypropylene's single reflection, pure graphite's single reflection, and depolarization caused by multiple reflections, which is consistent with the theoretical derivation. Reflection parameters of rough surface can be calculated from PCM decomposition, and the results fit well with the theoretical calculations provided by the Fresnel equations. These theoretical and experimental analyses verify that PCM is an efficient way to physically model light-matter interactions. PMID:26371930

  16. The Evolution of Extracellular Matrix

    PubMed Central

    Özbek, Suat; Balasubramanian, Prakash G.; Chiquet-Ehrismann, Ruth; Tucker, Richard P.

    2010-01-01

    We present a perspective on the molecular evolution of the extracellular matrix (ECM) in metazoa that draws on research publications and data from sequenced genomes and expressed sequence tag libraries. ECM components do not function in isolation, and the biological ECM system or “adhesome” also depends on posttranslational processing enzymes, cell surface receptors, and extracellular proteases. We focus principally on the adhesome of internal tissues and discuss its origins at the dawn of the metazoa and the expansion of complexity that occurred in the chordate lineage. The analyses demonstrate very high conservation of a core adhesome that apparently evolved in a major wave of innovation in conjunction with the origin of metazoa. Integrin, CD36, and certain domains predate the metazoa, and some ECM-related proteins are identified in choanoflagellates as predicted sequences. Modern deuterostomes and vertebrates have many novelties and elaborations of ECM as a result of domain shuffling, domain innovations and gene family expansions. Knowledge of the evolution of metazoan ECM is important for understanding how it is built as a system, its roles in normal tissues and disease processes, and has relevance for tissue engineering, the development of artificial organs, and the goals of synthetic biology. PMID:21160071

  17. Synchrotron FTIR Imaging For The Identification Of Cell Types Within Human Tissues

    SciTech Connect

    Walsh, Michael J.; Pounder, F. Nell; Nasse, Michael J.; Macias, Virgilia; Kajdacsy-Balla, Andre; Hirschmugl, Carol; Bhargava, Rohit

    2010-02-03

    The use of synchrotron Fourier Transform Infrared spectroscopy (S-FTIR) has been shown to be a very promising tool for biomedical research. S-FTIR spectroscopy allows for the fast acquisition of infrared (IR) spectra at a spatial resolution approaching the IR diffraction limit. The development of the Infrared Environmental Imaging (IRENI) beamline at the Synchrotron Radiation Center (SRC) at the University of Wisconsin-Madison has allowed for diffraction limited imaging measurements of cells in human prostate and breast tissues. This has allowed for the identification of cell types within tissues that would otherwise not have been resolvable using conventional FTIR sources.

  18. IR manifestation of water intermediates formation with sodium hydroxide and sodium salts in KBr matrix

    NASA Astrophysics Data System (ADS)

    Grinvald, I. I.; Vorotyntsev, V. M.; Vorotyntsev, I. V.; Kalagaev, I. Yu.; Vorotyntsev, A. V.; Salkina, S. V.; Petukhov, A. N.; Spirin, I. A.; Grushevskaya, A. I.

    2015-12-01

    The association of water with sodium hydroxide, sodium carbonate and sodium nitrate in a KBr matrix at room temperature, exhibited by FTIR data, was established. It was found that water intermediates form due to the intermolecular hydrogen bond and can be stabilized in the solid phase. The revealed clusters can exist in several shape of hydrates shell with different geometry and number of involved water molecules.

  19. Hypercube matrix computation task

    NASA Technical Reports Server (NTRS)

    Calalo, Ruel H.; Imbriale, William A.; Jacobi, Nathan; Liewer, Paulett C.; Lockhart, Thomas G.; Lyzenga, Gregory A.; Lyons, James R.; Manshadi, Farzin; Patterson, Jean E.

    1988-01-01

    A major objective of the Hypercube Matrix Computation effort at the Jet Propulsion Laboratory (JPL) is to investigate the applicability of a parallel computing architecture to the solution of large-scale electromagnetic scattering problems. Three scattering analysis codes are being implemented and assessed on a JPL/California Institute of Technology (Caltech) Mark 3 Hypercube. The codes, which utilize different underlying algorithms, give a means of evaluating the general applicability of this parallel architecture. The three analysis codes being implemented are a frequency domain method of moments code, a time domain finite difference code, and a frequency domain finite elements code. These analysis capabilities are being integrated into an electromagnetics interactive analysis workstation which can serve as a design tool for the construction of antennas and other radiating or scattering structures. The first two years of work on the Hypercube Matrix Computation effort is summarized. It includes both new developments and results as well as work previously reported in the Hypercube Matrix Computation Task: Final Report for 1986 to 1987 (JPL Publication 87-18).

  20. EPR and FTIR Spectroscopy of CARBON(4), CARBON(3) Hydrogen and Oxygen CARBON(3) Hydrogen in Solid Neon and Argon

    NASA Astrophysics Data System (ADS)

    Jiang, Qian

    The electron-paramagnetic-resonance spectrum of C_4 in a neon matrix at {~}4 K formed by the vacuum-ultraviolet photolysis of 1,3-butadiene has been investigated to seek evidence for the bending of the molecule, which had previously been indicated by the results of EPR and FTIR measurements made on C_4 trapped in argon at 10 K. The observed spectra, which include ^ {13}C hyperfine splitting and zero-field splitting data, confirm the splitting of the perpendicular xy_1 and xy_2 lines of triplet C_4 into separate x and y components, which is indicative of the unequivalent axes of a bent molecule. A Fourier transform infrared isotopic study has been made of the deuterium and carbon-13 substituted C _3H radical produced by trapping in solid Ar the products of the vacuum ultraviolet photolysis of CH_3CHCH_2 (propylene) or a mixture of methane and acetylene. The 1824.7 and 1159.8 cm^{-1} absorptions, which in earlier work using only deuterium isotosopic data could be assigned to either the cyclic or linear isomer, can now be definitely identified on the basis of extensive ^{13}C isotopic measurements as the nu_2(sigma^+) and nu_3(sigma^+) fundamentals of linear C_3H. The frequencies of the fundamentals and D and ^ {13}C isotopic shifts are in good agreement with the predictions of preliminary ab initio calculations for the linear isomer. The identification of a fundamental vibration of the HCCCO radical has been made, for the first time, in a FTIR study involving extensive isotopic measurements. An absorption at 2308.6 cm^{-1} has been assigned to the nu_2, antisymmetric CCCO stretching mode of HCCCO which was produced by trapping in Ar the products of the vacuum ultraviolet (VUV) photolysis of a mixture of acetylene and carbon monoxide. The assignment is confirmed by measurements for a variety of D, ^{18}O, and ^{13}C substituted isotopomers.

  1. Determination of drug content in semisolid formulations by non-invasive spectroscopic methods: FTIR - ATR, - PAS, - Raman and PDS

    NASA Astrophysics Data System (ADS)

    Gotter, B.; Faubel, W.; Heißler, St.; Hein, J.; Neubert, R. H. H.

    2010-03-01

    This study elucidates the potential use of photothermal deflection spectroscopy (PDS), FTIR photoacoustic (FTIR-PAS), FT Raman, and FTIR-attenuated total reflection (FTIR-ATR) spectroscopy as analytical tools for investigating the drug content in semisolid formulations. Regarding the analytical parameters, this study demonstrates the photothermal beam deflection to be definitely comparable to well established spectroscopic methods for this purpose. The correlation coefficients range from 0.990 to 0.999. Likewise, repeatability and limit of detection are comparable.

  2. Standard Errors for Matrix Correlations.

    ERIC Educational Resources Information Center

    Ogasawara, Haruhiko

    1999-01-01

    Derives the asymptotic standard errors and intercorrelations for several matrix correlations assuming multivariate normality for manifest variables and derives the asymptotic standard errors of the matrix correlations for two factor-loading matrices. (SLD)

  3. Network for the Detection of Stratospheric Change (NDSC) FTIR Intercomparison at Table Mountain Facility, November 1996

    NASA Technical Reports Server (NTRS)

    Toon, G.; Goldman, A.; Walsh, C.; Bell, W.; Blavier, J. -F.; Sen, B.; Coffey, M.; Hannigan, J.; Mankin, W.

    2000-01-01

    An intercomparison of four Fourier Transform Infrared (FTIR) spectrometers, operated side by side by JPL, NCAR, and NPL groups, using two different spectral fitting algorithms, was conducted at JPL's Table Mountain Facility (TMF) during November 1996.

  4. Evaluation of FTIR spectroscopy as diagnostic tool for colorectal cancer using spectral analysis

    NASA Astrophysics Data System (ADS)

    Dong, Liu; Sun, Xuejun; Chao, Zhang; Zhang, Shiyun; Zheng, Jianbao; Gurung, Rajendra; Du, Junkai; Shi, Jingsen; Xu, Yizhuang; Zhang, Yuanfu; Wu, Jinguang

    2014-03-01

    The aim of this study is to confirm FTIR spectroscopy as a diagnostic tool for colorectal cancer. 180 freshly removed colorectal samples were collected from 90 patients for spectrum analysis. The ratios of spectral intensity and relative intensity (/I1460) were calculated. Principal component analysis (PCA) and Fisher's discriminant analysis (FDA) were applied to distinguish the malignant from normal. The FTIR parameters of colorectal cancer and normal tissues were distinguished due to the contents or configurations of nucleic acids, proteins, lipids and carbohydrates. Related to nitrogen containing, water, protein and nucleic acid were increased significantly in the malignant group. Six parameters were selected as independent factors to perform discriminant functions. The sensitivity for FTIR in diagnosing colorectal cancer was 96.6% by discriminant analysis. Our study demonstrates that FTIR can be a useful technique for detection of colorectal cancer and may be applied in clinical colorectal cancer diagnosis.

  5. Identification of Cortex Eucommiae from different producing areas by FTIR microspectroscopy

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Sheng, Daping; Zhu, Zhengjie; Xu, Fangcheng; Huang, Dake; Yu, Changjun

    2015-04-01

    In this paper, FTIR microspectroscopy was used to compare Cortex Eucommiae from Anhui Province (A), Henan Province (B) and Sichuan Province (C) of China. High-resolution spectra were obtained with good reproducibility. From IR spectra, some obvious differences in band frequency could be observed among Cortex Eucommiae A-C. Curve fitting result indicated that polysaccharides' structures and contents were different among Cortex Eucommiae A-C. To distinguish Cortex Eucommiae from different producing areas, the A1245/A1328 ratio might be an exceptionally practical factor. Additionally, FTIR microspectroscopy could identify Cortex Eucommiae A-C with 89.5% accuracy in combination with hierarchical cluster analysis. The results suggest FTIR microspectroscopy is very easy and efficient for distinguishing Cortex Eucommiae from different areas, and also indicate FTIR microspectroscopy may be practical for TCM research.

  6. Effect of two hydrophobic polymers on the release of gliclazide from their matrix tablets.

    PubMed

    Hussain, Talib; Saeed, Tariq; Mumtaz, Ahmad M; Javaid, Zeeshan; Abbas, Khizar; Awais, Azeema; Idrees, Hafiz Arfat

    2013-01-01

    Gliclazide is an oral hypoglycemic agent, indicated in non insulin dependent diabetes mellitus and in patients with diabetic retinopathy. It has good tolerability and is a short acting sulfonyl urea that requires large dose to maintain the blood glucose level. So development of a sustained release formulation of gliclazide (GLZ) is required for better patient compliance. This study was conducted to assess the effects of different drug polymer ratios on the release profile of gliclazide from the matrix. Oral matrix tablets of gliclazide were prepared by hot melt method, using pure and blended mixture of glyceryl monostearate (GMS) and stearic acid (SA) in different ratios. In vitro release pattern was studied for 8 h in phosphate buffer media (pH 7.4). Different kinetic models including zero order, first order, Higuchi and Peppas were applied to evaluate drug release behavior. Drug excipient compatibility was evaluated by scanning with DSC and FTIR. Higuchi model was found the most appropriate model for describing the release profile of GLZ and non-Fickian release was found predominant mechanism of drug release. The release of drug from the matrix was greatly controlled by GMS while SA appeared to facilitate the release of drug from matrix tablets. FTIR results showed no chemical interaction between drug and the polymers, and DSC results indicated amorphous state of GLZ and polymers without significant complex formation. The results indicate that matrix tablets of gliclazide using glyceryl monostearate and stearic acid showed marked sustained release properties. PMID:23923399

  7. On the Matrix Exponential Function

    ERIC Educational Resources Information Center

    Hou, Shui-Hung; Hou, Edwin; Pang, Wan-Kai

    2006-01-01

    A novel and simple formula for computing the matrix exponential function is presented. Specifically, it can be used to derive explicit formulas for the matrix exponential of a general matrix A satisfying p(A) = 0 for a polynomial p(s). It is ready for use in a classroom and suitable for both hand as well as symbolic computation.

  8. Structural distinction between black and grey human hair: A FTIR investigation

    NASA Astrophysics Data System (ADS)

    Dutta, Arup; Sarkar, A.

    2013-06-01

    Hair is an important biomaterial primarily composed of structural protein, notably keratin. In this present work Fourier transformed infrared absorption (FTIR) spectrum of black and grey human hair is analyzed and compared from measured data of FTIR spectra. The change in characteristics bond vibration detected clearly. The obtained shift of the characteristics frequency caused due to change in molecular structure in the two types of human hair.

  9. The cellulose resource matrix.

    PubMed

    Keijsers, Edwin R P; Yılmaz, Gülden; van Dam, Jan E G

    2013-03-01

    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where large scale competition can be expected and already is observed for the traditional industries such as the paper industry. Cellulose and lignocellulosic raw materials (like wood and non-wood fibre crops) are being utilised in many industrial sectors. Due to the initiated transition towards biobased economy, these raw materials are intensively investigated also for new applications such as 2nd generation biofuels and 'green' chemicals and materials production (Clark, 2007; Lange, 2007; Petrus & Noordermeer, 2006; Ragauskas et al., 2006; Regalbuto, 2009). As lignocellulosic raw materials are available in variable quantities and qualities, unnecessary competition can be avoided via the choice of suitable raw materials for a target application. For example, utilisation of cellulose as carbohydrate source for ethanol production (Kabir Kazi et al., 2010) avoids the discussed competition with easier digestible carbohydrates (sugars, starch) deprived from the food supply chain. Also for cellulose use as a biopolymer several different competing markets can be distinguished. It is clear that these applications and markets will be influenced by large volume shifts. The world will have to reckon with the increase of competition and feedstock shortage (land use/biodiversity) (van Dam, de Klerk-Engels, Struik, & Rabbinge, 2005). It is of interest - in the context of sustainable development of the bioeconomy - to categorize the already available and emerging lignocellulosic resources in a matrix structure. When composing such "cellulose resource matrix" attention should be given to the quality aspects as well as to the available quantities and practical possibilities of processing the

  10. Sensitive detection of chemical agents and toxic industrial chemicals using active open-path FTIRs

    NASA Astrophysics Data System (ADS)

    Walter, William T.

    2004-03-01

    Active open-path FTIR sensors provide more sensitive detection of chemical agents than passive FTIRs, such as the M21 RSCAAL and JSLSCAD, and at the same time identify and quantify toxic industrial chemicals (TIC). Passive FTIRs are bistatic sensors relying on infrared sources of opportunity. Utilization of earth-based sources of opportunity limits the source temperatures available for passive chemical-agent FTIR sensors to 300° K. Active FTIR chemical-agent sensors utilize silicon carbide sources, which can be operated at 1500° K. The higher source temperature provides more than an 80-times increase in the infrared radiant flux emitted per unit area in the 7 to 14 micron spectral fingerprint region. Minimum detection limits are better than 5 μgm/m3 for GA, GB, GD, GF and VX. Active FTIR sensors can (1) assist first responders and emergency response teams in their assessment of and reaction to a terrorist threat, (2) provide information on the identification of the TIC present and their concentrations and (3) contribute to the understanding and prevention of debilitating disorders analogous to the Gulf War Syndrome for military and civilian personnel.

  11. FTIR, Raman, and CARS microscopic imaging for histopathologic assessment of brain tumors

    NASA Astrophysics Data System (ADS)

    Krafft, Christoph; Bergner, Norbert; Matthäus, Christian; Romeike, Bernd; Reichart, Rupert; Kalff, Rolf; Dietzek, B.,; Popp, Jürgen

    2010-02-01

    The contribution demonstrates how the molecular contrast of Fourier transform infrared (FTIR), Raman and coherent anti-Stokes Raman scattering (CARS) microscopic imaging can be applied for the histopathological assessment of brain tumors. Human brain tissue specimens were obtained from patients undergoing neurosurgery. Thin sections of control brain tissue from an epilepsy patient and tumor tissue from a meningioma patient were prepared on calciumfluoride slides which were appropriate substrates for data acquisition in transmission and reflection mode. All CARS images correlate well with the FTIR and Raman images. Whereas CARS images were collected within seconds, exposure times were minutes for FTIR imaging and hours for Raman imaging. CARS images in the interval 2750-3000 cm-1 mainly probed spectral contributions of lipids which are important diagnostic markers of brain tumors. It was demonstrated that the CARS profile in the interval 2750-3000 cm-1 differed between the control sample and meningioma. Full spectral information could be extracted from Raman and FTIR images that enabled to distinguish different tissue types in brain tumors. Based on the current results we suggest a complementary application of FTIR, Raman and CARS imaging. FTIR and Raman imaging defines spectral regions and spectral markers that are essential for tissue classification. CARS images at different Stokes shifts or in the multiplex mode probe these spectral descriptors at video-time frame rates.

  12. Toxigenic Corynebacterium ulcerans isolated from a free-roaming red fox (Vulpes vulpes).

    PubMed

    Sting, Reinhard; Ketterer-Pintur, Sandra; Contzen, Matthias; Mauder, Norman; Süss-Dombrowski, Christine

    2015-01-01

    Corynebacterium (C.) ulcerans could be isolated from the spleen of a red fox (Vulpes vulpes) that had been found dead in the state of Baden-Württemberg, Germany. Pathohistological examination suggested that the fox had died of distemper, as was confirmed by PCR. The isolate was identified biochemically, by MALDI-TOF MS, FT-IR and by partial 16S rRNA, rpoB and tox gene sequencing. Using the Elek test the C. ulcerans isolate demonstrated diphtheria toxin production. FT-IR and sequencing data obtained from the C. ulcerans isolate from the red fox showed higher similarity to isolates from humans than to those from wild game. PMID:26054226

  13. X-ray, FT-IR, NMR and PM5 structural studies and antibacterial activity of unexpectedly stable salinomycin-benzotriazole intermediate ester

    NASA Astrophysics Data System (ADS)

    Huczyński, Adam; Janczak, Jan; Antoszczak, Michał; Stefańska, Joanna; Brzezinski, Bogumil

    2012-08-01

    The unexpectedly stable benzotriazole ester of salinomycin (SAL-HOBt) - an intermediate product of the amidation reaction of salinomycin has been isolated and structurally characterised (using a single crystal) by X-ray, FT-IR, NMR and semiempirical methods. The results of the X-ray and spectroscopic studies demonstrated that this intermediate ester exist in the solid state and in solution exclusively as the stable O-acyl form. The molecular structure of SAL-HOBt is stabilised by relatively weak intramolecular hydrogen bonds. The PM5 calculation of possible structures of SAL-HOBt has shown that the O-acyl form is more energetically favourable than its N-oxide-N-acyl isomers. The antimicrobial tests show that SAL-HOBt is active against Gram-positive bacteria and clinical isolates methicillin-resistant Staphylococcus aureus (MIC = 1-2 μg/ml).

  14. Design of RF MEMS based switch matrix for space applications

    NASA Astrophysics Data System (ADS)

    Di Nardo, S.; Farinelli, P.; Kim, T.; Marcelli, R.; Margesin, B.; Paola, E.; Pochesci, D.; Vietzorreck, L.; Vitulli, F.

    2013-07-01

    RF MEMS based switch matrices have several advantages compared to the mechanical or solid-state switch based ones for space applications. They are compact, light and less lossy with a high linearity up to high frequency. In this work, a 12 × 12 switch matrix with RF MEMS and LTCC technologies is presented based on the planar Beneš network. The simulated performance of the 12 × 12 switch matrix is below -12 dB IL (Insertion Loss) up to C band and -15 dB RL (Return Loss) up to Ku band. Moreover, it has a good isolation better than -50 dB. A 4 × 4 switch matrix with the same design process and technologies is fabricated and measured to verify the 12 × 12 switch matrix design process. The measured performance agrees very well to the simulations.

  15. Detection of PLGA-based nanoparticles at a single-cell level by synchrotron radiation FTIR spectromicroscopy and correlation with X-ray fluorescence microscopy

    PubMed Central

    Pascolo, Lorella; Bortot, Barbara; Benseny-Cases, Nuria; Gianoncelli, Alessandra; Tosi, Giovanni; Ruozi, Barbara; Rizzardi, Clara; De Martino, Eleonora; Vandelli, Maria Angela; Severini, Giovanni Maria

    2014-01-01

    Poly-lactide-co-glycolide (PLGA) is one of the few polymers approved by the US Food and Drug Administration as a carrier for drug administration in humans; therefore, it is one of the most used materials in the formulation of polymeric nanoparticles (NPs) for therapeutic purposes. Because the cellular uptake of polymeric NPs is a hot topic in the nanomedicine field, the development of techniques able to ensure incontrovertible evidence of the presence of NPs in the cells plays a key role in gaining understanding of their therapeutic potential. On the strength of this premise, this article aims to evaluate the application of synchrotron radiation-based Fourier transform infrared spectroscopy (SR-FTIR) spectromicroscopy and SR X-ray fluorescence (SR-XRF) microscopy in the study of the in vitro interaction of PLGA NPs with cells. To reach this goal, we used PLGA NPs, sized around 200 nm and loaded with superparamagnetic iron oxide NPs (PLGA-IO-NPs; Fe3O4; size, 10–15 nm). After exposing human mesothelial (MeT5A) cells to PLGA-IO-NPs (0.1 mg/mL), the cells were analyzed after fixation both by SR-FTIR spectromicroscopy and SR-XRF microscopy setups. SR-FTIR-SM enabled the detection of PLGA NPs at single-cell level, allowing polymer detection inside the biological matrix by the characteristic band in the 1,700–2,000 cm−1 region. The precise PLGA IR-signature (1,750 cm−1 centered pick) also was clearly evident within an area of high amide density. SR-XRF microscopy performed on the same cells investigated under SR-FTIR microscopy allowed us to put in evidence the Fe presence in the cells and to emphasize the intracellular localization of the PLGA-IO-NPs. These findings suggest that SR-FTIR and SR-XRF techniques could be two valuable tools to follow the PLGA NPs’ fate in in vitro studies on cell cultures. PMID:24944512

  16. Ceramic matrix and resin matrix composites: A comparison

    NASA Technical Reports Server (NTRS)

    Hurwitz, Frances I.

    1987-01-01

    The underlying theory of continuous fiber reinforcement of ceramic matrix and resin matrix composites, their fabrication, microstructure, physical and mechanical properties are contrasted. The growing use of organometallic polymers as precursors to ceramic matrices is discussed as a means of providing low temperature processing capability without the fiber degradation encountered with more conventional ceramic processing techniques. Examples of ceramic matrix composites derived from particulate-filled, high char yield polymers and silsesquioxane precursors are provided.

  17. Ceramic matrix and resin matrix composites - A comparison

    NASA Technical Reports Server (NTRS)

    Hurwitz, Frances I.

    1987-01-01

    The underlying theory of continuous fiber reinforcement of ceramic matrix and resin matrix composites, their fabrication, microstructure, physical and mechanical properties are contrasted. The growing use of organometallic polymers as precursors to ceramic matrices is discussed as a means of providing low temperature processing capability without the fiber degradation encountered with more conventional ceramic processing techniques. Examples of ceramic matrix composites derived from particulate-filled, high char yield polymers and silsesquioxane precursors are provided.

  18. Light cone matrix product

    SciTech Connect

    Hastings, Matthew B

    2009-01-01

    We show how to combine the light-cone and matrix product algorithms to simulate quantum systems far from equilibrium for long times. For the case of the XXZ spin chain at {Delta} = 0.5, we simulate to a time of {approx} 22.5. While part of the long simulation time is due to the use of the light-cone method, we also describe a modification of the infinite time-evolving bond decimation algorithm with improved numerical stability, and we describe how to incorporate symmetry into this algorithm. While statistical sampling error means that we are not yet able to make a definite statement, the behavior of the simulation at long times indicates the appearance of either 'revivals' in the order parameter as predicted by Hastings and Levitov (e-print arXiv:0806.4283) or of a distinct shoulder in the decay of the order parameter.

  19. Google matrix of Twitter

    NASA Astrophysics Data System (ADS)

    Frahm, K. M.; Shepelyansky, D. L.

    2012-10-01

    We construct the Google matrix of the entire Twitter network, dated by July 2009, and analyze its spectrum and eigenstate properties including the PageRank and CheiRank vectors and 2DRanking of all nodes. Our studies show much stronger inter-connectivity between top PageRank nodes for the Twitter network compared to the networks of Wikipedia and British Universities studied previously. Our analysis allows to locate the top Twitter users which control the information flow on the network. We argue that this small fraction of the whole number of users, which can be viewed as the social network elite, plays the dominant role in the process of opinion formation on the network.

  20. Hyaluronan: A Matrix Component

    NASA Astrophysics Data System (ADS)

    Rügheimer, Louise

    2008-09-01

    The glucosaminoglycan hyaluronan is a key component of the extracellular matrix. It is a large, negatively charged molecule that can act as an ion exchange reservoir for positive ions. Hyaluronan is involved in renomedullary water handling through its water-binding capacity. In the renal medulla, the main source for hyaluronan production is the renomedullary interstitial cells. Hyaluronan synthases are found in the inner part of the plasma membrane and polymerize hyaluronan chains which are extruded into the extracellular space. Hyaluronidases are a family of enzymes involved in the degradation of hyaluronan. They have a wide range of properties, including differences in size, inhibitor sensitivities, catalytic mechanisms, substrate specificities and pH optima.

  1. Mixed Mode Matrix Multiplication

    SciTech Connect

    Meng-Shiou Wu; Srinivas Aluru; Ricky A. Kendall

    2004-09-30

    In modern clustering environments where the memory hierarchy has many layers (distributed memory, shared memory layer, cache,...), an important question is how to fully utilize all available resources and identify the most dominant layer in certain computations. When combining algorithms on all layers together, what would be the best method to get the best performance out of all the resources we have? Mixed mode programming model that uses thread programming on the shared memory layer and message passing programming on the distributed memory layer is a method that many researchers are using to utilize the memory resources. In this paper, they take an algorithmic approach that uses matrix multiplication as a tool to show how cache algorithms affect the performance of both shared memory and distributed memory algorithms. They show that with good underlying cache algorithm, overall performance is stable. When underlying cache algorithm is bad, superlinear speedup may occur, and an increasing number of threads may also improve performance.

  2. Matrix membranes and integrability

    SciTech Connect

    Zachos, C.; Fairlie, D.; Curtright, T.

    1997-06-01

    This is a pedagogical digest of results reported in Curtright, Fairlie, {ampersand} Zachos 1997, and an explicit implementation of Euler`s construction for the solution of the Poisson Bracket dual Nahm equation. But it does not cover 9 and 10-dimensional systems, and subsequent progress on them Fairlie 1997. Cubic interactions are considered in 3 and 7 space dimensions, respectively, for bosonic membranes in Poisson Bracket form. Their symmetries and vacuum configurations are explored. Their associated first order equations are transformed to Nahm`s equations, and are hence seen to be integrable, for the 3-dimensional case, by virtue of the explicit Lax pair provided. Most constructions introduced also apply to matrix commutator or Moyal Bracket analogs.

  3. The studies of FT-IR and CD spectroscopy on catechol oxidase I from tobacco

    NASA Astrophysics Data System (ADS)

    Xiao, Hourong; Xie, Yongshu; Liu, Qingliang; Xu, Xiaolong; Shi, Chunhua

    2005-10-01

    A novel copper-containing enzyme named COI (catechol oxidase I) has been isolated and purified from tobacco by extracting acetone-emerged powder with phosphate buffer, centrifugation at low temperature, ammonium sulfate fractional precipitation, and column chromatography on DEAE-sephadex (A-50), sephadex (G-75), and DEAE-celluse (DE-52). PAGE, SDS-PAGE were used to detect the enzyme purity, and to determine its molecular weight. Then the secondary structures of COI at different pH, different temperatures and different concentrations of guanidine hydrochloride (GdnHCl) were studied by the FT-IR, Fourier self-deconvolution spectra, and circular dichroism (CD). At pH 2.0, the contents of both α-helix and anti-parallel β-sheet decrease, and that of random coil increases, while β-turn is unchanged compared with the neutral condition (pH 7.0). At pH 11.0, the results indicate that the contents of α-helix, anti-parallel β-sheet and β-turn decrease, while random coil structure increases. According to the CD measurements, the relative average fractions of α-helix, anti-parallel β-sheet, β-turn/parallel β-sheet, aromatic residues and disulfide bond, and random coil/γ-turn are 41.7%, 16.7%, 23.5%, 11.3%, and 6.8% at pH 7.0, respectively, while 7.2%, 7.7%, 15.2%, 10.7%, 59.2% at pH 2.0, and 20.6%, 9.5%, 15.2%, 10.5%, 44.2% at pH 11.0. Both α-helix and random coil decrease with temperature increasing, and anti-parallel β-sheet increases at the same time. After incubated in 6 mol/L guanidine hydrochloride for 30 min, the fraction of α-helix almost disappears (only 1.1% left), while random coil/γ-turn increases to 81.8%, which coincides well with the results obtained through enzymatic activity experiment.

  4. Extracellular matrix mineralization in murine MC3T3-E1 osteoblast cultures: an ultrastructural, compositional and comparative analysis with mouse bone.

    PubMed

    Addison, W N; Nelea, V; Chicatun, F; Chien, Y-C; Tran-Khanh, N; Buschmann, M D; Nazhat, S N; Kaartinen, M T; Vali, H; Tecklenburg, M M; Franceschi, R T; McKee, M D

    2015-02-01

    Bone cell culture systems are essential tools for the study of the molecular mechanisms regulating extracellular matrix mineralization. MC3T3-E1 osteoblast cell cultures are the most commonly used in vitro model of bone matrix mineralization. Despite the widespread use of this cell line to study biomineralization, there is as yet no systematic characterization of the mineral phase produced in these cultures. Here we provide a comprehensive, multi-technique biophysical characterization of this cell culture mineral and extracellular matrix, and compare it to mouse bone and synthetic apatite mineral standards, to determine the suitability of MC3T3-E1 cultures for biomineralization studies. Elemental compositional analysis by energy-dispersive X-ray spectroscopy (EDS) showed calcium and phosphorus, and trace amounts of sodium and magnesium, in both biological samples. X-ray diffraction (XRD) on resin-embedded intact cultures demonstrated that similar to 1-month-old mouse bone, apatite crystals grew with preferential orientations along the (100), (101) and (111) mineral planes indicative of guided biogenic growth as opposed to dystrophic calcification. XRD of crystals isolated from the cultures revealed that the mineral phase was poorly crystalline hydroxyapatite with 10 to 20nm-sized nanocrystallites. Consistent with the XRD observations, electron diffraction patterns indicated that culture mineral had low crystallinity typical of biological apatites. Fourier-transform infrared spectroscopy (FTIR) confirmed apatitic carbonate and phosphate within the biological samples. With all techniques utilized, cell culture mineral and mouse bone mineral were remarkably similar. Scanning (SEM) and transmission (TEM) electron microscopy showed that the cultures had a dense fibrillar collagen matrix with small, 100nm-sized, collagen fibril-associated mineralization foci which coalesced to form larger mineral aggregates, and where mineralized sites showed the accumulation of the

  5. Evaluation of shooting distance by AFM and FTIR/ATR analysis of GSR.

    PubMed

    Mou, Yongyan; Lakadwar, Jyoti; Rabalais, J Wayne

    2008-11-01

    The techniques of atomic force microscopy (AFM) and Fourier transform infrared attenuated total reflectance (FTIR/ATR) spectroscopy are applied to the analysis of gun-shot residue (GSR) to test their ability to determine shooting distance and discrimination of the powder manufacturers. AFM is a nondestructive technique that is capable of characterizing the shapes and size distributions of GSR particles with resolution down to less than a nanometer. This may be useful for estimation of the shooting distance. Our AFM images of GSR show that the size distribution of the particles is inversely proportional to the shooting distance. Discrimination of powder manufacturers is tested by FTIR/ATR investigation of GSR. Identifying the specific compounds in the GSR by FTIR/ATR was not possible because it is a mixture of the debris of several compounds that compose the residue. However, it is shown that the GSR from different cartridges has characteristic FTIR/ATR bands that may be useful in differentiating the powder manufacturers. It appears promising that the development of AFM and FTIR/ATR databases for various powder manufacturers may be useful in analysis and identification of GSR. PMID:18761553

  6. Ectomycorrhizal identification in environmental samples of tree roots by Fourier-transform infrared (FTIR) spectroscopy

    PubMed Central

    Pena, Rodica; Lang, Christa; Naumann, Annette; Polle, Andrea

    2014-01-01

    Roots of forest trees are associated with various ectomycorrhizal (ECM) fungal species that are involved in nutrient exchange between host plant and the soil compartment. The identification of ECM fungi in small environmental samples is difficult. The present study tested the feasibility of attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy followed by hierarchical cluster analysis (HCA) to discriminate in situ collected ECM fungal species. Root tips colonized by distinct ECM fungal species, i.e., Amanita rubescens, Cenococcum geophilum, Lactarius subdulcis, Russula ochroleuca, and Xerocomus pruinatus were collected in mono-specific beech (Fagus sylvatica) and mixed deciduous forests in different geographic areas to investigate the environmental variability of the ECM FTIR signatures. A clear HCA discrimination was obtained for ECM fungal species independent of individual provenance. Environmental variability neither limited the discrimination between fungal species nor provided sufficient resolution to discern species sub-clusters for different sites. However, the de-convoluted FTIR spectra contained site-related spectral information for fungi with wide nutrient ranges, but not for Lactarius subdulcis, a fungus residing only in the litter layer. Specific markers for distinct ECM were identified in spectral regions associated with carbohydrates (i.e., mannans), lipids, and secondary protein structures. The present results support that FTIR spectroscopy coupled with multivariate analysis is a reliable and fast method to identify ECM fungal species in minute environmental samples. Moreover, our data suggest that the FTIR spectral signatures contain information on physiological and functional traits of ECM fungi. PMID:24904624

  7. Methodology for fiber-optic Raman mapping and FTIR imaging of metastases in mouse brains.

    PubMed

    Krafft, Christoph; Kirsch, Matthias; Beleites, Claudia; Schackert, Gabriele; Salzer, Reiner

    2007-10-01

    The objectives of this study were to optimize the preparation of pristine brain tissue to obtain reference information, to optimize the conditions for introducing a fiber-optic probe to acquire Raman maps, and to transfer previous results obtained from human brain tumors to an animal model. Brain metastases of malignant melanomas were induced by injecting tumor cells into the carotid artery of mice. The procedure mimicked hematogenous tumor spread in one brain hemisphere while the other hemisphere remained tumor free. Three series of sections were prepared consecutively from whole mouse brains: dried, thin sections for FTIR imaging, hematoxylin and eosin-stained thin sections for histopathological assessment, and pristine, 2-mm thick sections for Raman mapping. FTIR images were recorded using a spectrometer with a multi-channel detector. Raman maps were collected serially using a spectrometer coupled to a fiber-optic probe. The FTIR images and the Raman maps were segmented by cluster analysis. The color-coded cluster memberships coincided well with the morphology of mouse brains in stained tissue sections. More details in less time were resolved in FTIR images with a nominal resolution of 25 microm than in Raman maps collected with a laser focus 60 microm in diameter. The spectral contributions of melanin in tumor cells were resonance enhanced in Raman spectra on excitation at 785 nm which enabled their sensitive detection in Raman maps. Possible reasons why metastatic cells of malignant melanomas were not identified in FTIR images are discussed. PMID:17639353

  8. Influence of gas packing and orientation on FTIR activity for CO chemisorption to the Cu paddlewheel.

    PubMed

    Wang, Cheng-Yu; Ray, Paramita; Gong, Qihan; Zhao, Yonggang; Li, Jing; Lueking, Angela D

    2015-10-28

    In situ Fourier-transform infrared (FTIR) spectroscopy is able to probe structural defects via site-specific adsorption of CO to the Cu-BTC (BTC = 1,3,5-benzenetricarboxylate) metal-organic framework (MOF). The temperature-programmed desorption (TPD) of CO chemisorbed to Cu-TDPAT (TDPAT = 2,4,6-tris(3,5-dicarboxylphenylamino)-1,3,5-triazine) is virtually identical to Cu-BTC, suggesting CO chemisorbs to the open metal site at the axial position of the copper paddlewheel that is the building unit of both MOFs. Yet, despite an increased gravimetric CO : Cu ratio, CO chemisorbed to Cu-TDPAT is FTIR inactive. We rule out the presence of residual solvent, thermal degradation, adsorption temperature, and ligand-induced electronic effects at the adsorption site. TPD at increased pressure suggests the multiple CO per Cu site rearrange in Cu-TDPAT as a dynamic function of temperature and pressure. Thus, the FTIR inactivity of CO chemisorbed to Cu-TDPAT is attributed to orientation and/or packing of the CO relative to the Cu binding site. The results suggest dynamic chemisorption complicate extension of a site-specific in situ FTIR probe of gas adsorption. For both Cu-BTC and Cu-TDPAT, the in situ FTIR probe is a less sensitive probe of defects than X-ray photoelectron spectroscopy and nitrogen adsorption. PMID:26395358

  9. Chemical mapping of tumor progression by FT-IR imaging: towards molecular histopathology.

    PubMed

    Petibois, Cyril; Déléris, Gérard

    2006-10-01

    Fourier-transform infrared (FT-IR) spectro-imaging enables global analysis of samples, with resolution close to the cellular level. Recent studies have shown that FT-IR imaging enables determination of the biodistribution of several molecules of interest (carbohydrates, lipids, proteins) for tissue analysis without pre-analytical modification of the sample such as staining. Molecular structure information is also available from the same analysis, notably for protein secondary structure and fatty acyl chain peroxidation level. Thus, several cancer markers can be identified from FT-IR tissue images, enabling accurate discrimination between healthy and tumor areas. FT-IR imaging applications are now able to provide unique chemical and morphological information about tissue status. With the fast image acquisition provided by modern mid-infrared imaging systems, it is now envisaged to analyze cerebral tumor exereses in delays compatible with neurosurgery. Accordingly, we propose to take FT-IR imaging into consideration for the development of new molecular histopathology tools. PMID:16935373

  10. [Determination of the carboxyl content of oxidized starch by fourier transform infrared (FTIR) spectroscopy].

    PubMed

    Ding, Long-Long; Zhang, Yan-Hua; Gu, Ji-You; Tan, Hai-Yan; Zhu, Li-Bin

    2014-02-01

    In the present study, the carboxyl content of oxidized starch was determined by FTIR spectroscopy. Standard curve was drawn in which the ordinate was carboxyl content determined by national standard method with the ratio of carbonyl absorbance to the key of C-H absorbance in FTIR spectroscopy as the abscissa. The ratio of absorbance of unknown oxidized starch tested by FTIR spectroscopy was obtained, The carboxyl content was calculated by standard curve, and then compared with the carboxyl content determined by national standard method, and the deviation is between 2% and 4%. In order to improve the accuracy of the experiment, standard sample was selected to draw standard curve to better ensure that the carboxyl content of the unknown oxidized starch is in the range of standard curve calculation limit, and deviates from the limit of standard curve. Compared with the carboxyl content determined by national standard method, testing with FTIR spectroscopy is simple, easy to operate, and of high efficiency and better accuracy. So, it is significant to forecast the carboxyl content of oxidized starch by FTIR spectroscopy. PMID:24822409

  11. Tailoring the Matrix in Ultra-Nanocrystalline Diamond Films

    NASA Astrophysics Data System (ADS)

    Buck, Volker; Woehrl, Nicolas

    2008-10-01

    By depositing films in argon-rich plasmas it is possible to produce ultra-nanocrystalline diamond (UNCD) films with grain sizes of 5-100 nm. By reducing the grain size, these films feature rather distinctive combinations of properties making them potential materials for emerging technological developments such as nano/micro-electro-mechanical systems (N/MEMS), optical coatings, bioelectronics, surface acoustic wave (SAW) filters, and tribological applications. The majority of works dealing with nanocrystalline diamond (NCD) up to now have concentrated on diamond grains (e.g., grain size, texture). In doing so the surrounding crystal matrix has been neglected and its effect on the substrate properties has been dismissed as a grain boundary effect. This view does not accord with its relevance to film properties. Because the matrix consists of amorphous carbon structures, approved methods for the characterization of this appropriate special class of materials were used here such as Raman and Fourier transform infrared spectroscopy (FTIR). The use of an amorphous matrix for nanocrystalline diamond grains has lead to an enormous field of new materials, because a whole class of carbon-based materials (diamondlike carbon, DLC) can be used as a matrix that may contain only carbon (a-C) or carbon and hydrogen (a-C:H) as well as other components such as metals (Me-C:H); additionally, other dopants such as silicon, oxygen, halogens, or nitrogen may be included. As an example, it is shown how the mechanical stress in films can be adjusted by tailoring the matrix.

  12. A matrix model for WZW

    NASA Astrophysics Data System (ADS)

    Dorey, Nick; Tong, David; Turner, Carl

    2016-08-01

    We study a U( N) gauged matrix quantum mechanics which, in the large N limit, is closely related to the chiral WZW conformal field theory. This manifests itself in two ways. First, we construct the left-moving Kac-Moody algebra from matrix degrees of freedom. Secondly, we compute the partition function of the matrix model in terms of Schur and Kostka polynomials and show that, in the large N limit, it coincides with the partition function of the WZW model. This same matrix model was recently shown to describe non-Abelian quantum Hall states and the relationship to the WZW model can be understood in this framework.

  13. FTIR, FT-Raman, ab initio and density functional studies on 4-methyl-1,3-dioxolan-2-one and 4,5-dichloro-1,3-dioxolan-2-one

    NASA Astrophysics Data System (ADS)

    Arjunan, V.; Saravanan, I.; Ravindran, P.; Mohan, S.

    2010-09-01

    The Fourier transform infrared (FTIR) and FT-Raman spectra of 4-methyl-1,3-dioxolan-2-one and 4,5-dichloro-1,3-dioxolan-2-one have been recorded in the range 3700-400 and 3700-100 cm -1, respectively. The complete vibrational assignment and analysis of the fundamental modes of the compounds were carried out using the observed FTIR and FT-Raman data. The vibrational frequencies determined experimentally were compared with those obtained theoretically from ab initio HF and DFT-B3LYP gradient calculations employing 6-311++G** and cc-pVTZ basis sets for the optimised geometries of the compounds. The geometries and normal modes of vibration obtained from the HF and DFT methods are in good agreement with the experimental data. The normal coordinate analysis was also carried out with ab initio force fields utilising Wilson's FG matrix method. The interactions of the skeletal vibrational modes were investigated.

  14. Classification of the biological material with use of FTIR spectroscopy and statistical analysis.

    PubMed

    Bombalska, Aneta; Mularczyk-Oliwa, Monika; Kwaśny, Mirosław; Włodarski, Maksymilian; Kaliszewski, Miron; Kopczyński, Krzysztof; Szpakowska, Małgorzata; Trafny, Elżbieta A

    2011-04-01

    Rapid detection and discrimination of dangerous biological materials such as bacteria and their spores has become a security aim of considerable importance. Various analytical methods, including FTIR spectroscopy combined with statistical analysis have been used to identify vegetative bacteria, bacterial spores and background interferants. The present work discusses the application of FTIR technique performed in reflectance mode using Horizontal Attenuated Total Reflectance accessory (HATR) to the discrimination of biological materials. In comparison with transmission technique the HATR is more rapid and do not require the sample destruction, simultaneously giving similar absorbance bands. HATR-FTIR results combined with statistical analysis PCA and HCA demonstrate that this combination provides novel and accurate microbial identification technique. PMID:21257340

  15. Classification of the biological material with use of FTIR spectroscopy and statistical analysis

    NASA Astrophysics Data System (ADS)

    Bombalska, Aneta; Mularczyk-Oliwa, Monika; Kwaśny, Mirosław; Włodarski, Maksymilian; Kaliszewski, Miron; Kopczyński, Krzysztof; Szpakowska, Małgorzata; Trafny, Elżbieta A.

    2011-04-01

    Rapid detection and discrimination of dangerous biological materials such as bacteria and their spores has become a security aim of considerable importance. Various analytical methods, including FTIR spectroscopy combined with statistical analysis have been used to identify vegetative bacteria, bacterial spores and background interferants. The present work discusses the application of FTIR technique performed in reflectance mode using Horizontal Attenuated Total Reflectance accessory (HATR) to the discrimination of biological materials. In comparison with transmission technique the HATR is more rapid and do not require the sample destruction, simultaneously giving similar absorbance bands. HATR-FTIR results combined with statistical analysis PCA and HCA demonstrate that this combination provides novel and accurate microbial identification technique.

  16. [Passive remote measurement of flame infrared image by a FTIR scanning imaging system].

    PubMed

    Liu, Zhi-Ming; Gao, Min-Guang; Liu, Wen-Qing; Lu, Yi-Huai; Zhang, Tian-Shu; Xu, Liang; Wei, Xiu-Li

    2008-11-01

    The present paper introduced a FTIR scanning imaging system. This system is based on the combination of a FTIR spectrometer and a scanning mirror. So it has the advantage of FTIR spectrometer: non-contact, real-time, celerity, nicety and high sensitivity. Through scanning mirror, the authors can obtain the space information of targets. The authors used this system to measure the flames infrared emission spectra of three alcohol burners at a flat roof in our laboratory. According to Planck's law, the authors calculated the relative temperature of from each spectrum. These temperature data formed an array. The authors used matlab software to plot the infrared images of target and contrasted them with video image. They were consistent with each other very well. This experiment allowed us to obtain the temperature distribution of three alcohol burners' flames, and provide identification, visualization, and quantification of pollutant clouds. PMID:19271480

  17. Raman and FTIR microscopic imaging of colon tissue: a comparative study.

    PubMed

    Krafft, Christoph; Codrich, Daniela; Pelizzo, Gloria; Sergo, Valter

    2008-05-01

    Colon tissue constitutes a valid model for the comparative analysis of soft tissue by Raman and Fourier transform infrared (FTIR) imaging because it contains four major tissue types such as muscle tissue, connective tissue, epithelium and nerve cells. Raman microscopic images were recorded in the mapping mode using 785 nm laser excitation and a step size of 10 microm from three regions within a thin section that encompassed mucus, mucosa, submucosa, and longitudinal and circular muscle layers. FTIR microscopic images that were composed of 4, 8 and 9 individual images of 4096 spectra each were recorded from the same regions using a FTIR spectrometer coupled to a microscope with a focal plane array detector. Furthermore, Raman microscopic images were recorded at a step size of 2.5 microm from three ganglia that belong to the myenteric plexus. The results are discussed with respect to lateral resolution, spectral resolution, acquisition time and sensitivity of both modalities. PMID:19343646

  18. FTIR characterization of Mexican honey and its adulteration with sugar syrups by using chemometric methods

    NASA Astrophysics Data System (ADS)

    Rios-Corripio, M. A.; Rios-Leal, E.; Rojas-López, M.; Delgado-Macuil, R.

    2011-01-01

    A chemometric analysis of adulteration of Mexican honey by sugar syrups such as corn syrup and cane sugar syrup was realized. Fourier transform infrared spectroscopy (FTIR) was used to measure the absorption of a group of bee honey samples from central region of Mexico. Principal component analysis (PCA) was used to process FTIR spectra to determine the adulteration of bee honey. In addition to that, the content of individual sugars from honey samples: glucose, fructose, sucrose and monosaccharides was determined by using PLS-FTIR analysis validated by HPLC measurements. This analytical methodology which is based in infrared spectroscopy and chemometry can be an alternative technique to characterize and also to determine the purity and authenticity of nutritional products as bee honey and other natural products.

  19. Attenuated total reflection Fourier-transform infrared (ATR-FTIR) imaging of tissues and live cells.

    PubMed

    Andrew Chan, K L; Kazarian, Sergei G

    2016-03-29

    FTIR spectroscopic imaging is a label-free, non-destructive and chemically specific technique that can be utilised to study a wide range of biomedical applications such as imaging of biopsy tissues, fixed cells and live cells, including cancer cells. In particular, the use of FTIR imaging in attenuated total reflection (ATR) mode has attracted much attention because of the small, but well controlled, depth of penetration and corresponding path length of infrared light into the sample. This has enabled the study of samples containing large amounts of water, as well as achieving an increased spatial resolution provided by the high refractive index of the micro-ATR element. This review is focused on discussing the recent developments in FTIR spectroscopic imaging, particularly in ATR sampling mode, and its applications in the biomedical science field as well as discussing the future opportunities possible as the imaging technology continues to advance. PMID:26488803

  20. Rapid Contamination During Storage of Carbonaceous Chondrites Prepared for Micro FTIR Measurements

    NASA Technical Reports Server (NTRS)

    Kebukawa, Yoko; Nakashima, Satoru; Otsuka, Takahiro; Nakamura-Messenger, Keiko; Zolensky, ichael E.

    2008-01-01

    The carbonaceous chondrites Tagish Lake and Murchison, which contain abundant hydrous minerals, when pressed on aluminum plates and analyzed by micro FTIR, were found to have been contaminated during brief (24 hours) storage. This contamination occurred when the samples were stored within containers which included silicone rubber, silicone grease or adhesive tape. Long-path gas cell FTIR measurements for silicone rubber revealed the presence of contaminant volatile molecules having 2970 cm(sup -1) (CH3) and 1265 cm(sup -1) (Si-CH3) peaks. These organic contaminants are found to be desorbed by in-situ heating infrared measurements from room temperature to 200-300 C. Careful preparation and storage are therefore needed for precious astronomical samples such as meteorites, IDPs and mission returned samples from comets, asteroids and Mars, if useful for FTIR measurements are to be made.

  1. Detection and grading of human gliomas by FTIR spectroscopy and a genetic classification algorithm

    NASA Astrophysics Data System (ADS)

    Steiner, Gerald; Shaw, R. A.; Choo-Smith, Lin-P'ing; Steller, Wolfram; Shapoval, Laryssa; Schackert, Gabriele; Sobottka, Stephan; Salzer, Reiner; Mantsch, Henry H.

    2002-03-01

    A new approach is presented to distinguish cancerous from normal brain tissue via linear discriminant analysis of Fourier transform infrared (FTIR) spectra. FTIR microspectroscopy was used to map various thin-section tumor samples with different malignancy grades (grades II-VI) and non-tumor samples obtained from various patients by surgical removal. Spectral analysis revealed features characteristic of tumors with increasing malignancy. A genetic region selection algorithm combined with linear discriminant analysis was used to derive classifiers distinguishing among spectra of control tissue, astrocytoma grade II, astrocytoma grade III and glioblastoma grade IV. Employing the World Health Organization histopathological diagnostic scheme as the gold standard, the spectra were classified with a success rate of approximately 85 percent. These results demonstrate the potential of the combination of FTIR spectroscopy and pattern recognition routines in providing a more objective method for brain tumour grading and diagnosis.

  2. Matrix market: a web resource for test matrix collection

    SciTech Connect

    Boisvert, R.F.; Pozo, R.; Remington, K.; Barrett, R.F.; Dongarra, J.J. /

    1996-05-30

    We describe a repository of data for the testing of numerical algorithms and mathematical software for matrix computations. The repository is designed to accommodate both dense and sparse matrices, as well as software to generate matrices. It has been seeded with the well known Harwell-Boeing sparse matrix collection. The raw data files have been augmented with an integrated World Wide Web interface which describes the matrices in the collection quantitatively and visually, For example, each matrix has a Web page which details its attributes, graphically depicts its sparsity pattern, and provides access to the matrix itself in several formats. In addition, a search mechanism is included which allows retrieval of matrices based on a variety of attributes, such as type and size, as well as through free-text search in abstracts. The URL is http://math.nist.gov/MatrixMarket.

  3. Glass matrix armor

    DOEpatents

    Calkins, Noel C.

    1991-01-01

    An armor system which utilizes glass. A plurality of constraint cells are mounted on a surface of a substrate, which is metal armor plate or a similar tough material, such that the cells almost completely cover the surface of the substrate. Each constraint cell has a projectile-receiving wall parallel to the substrate surface and has sides which are perpendicular to and surround the perimeter of the receiving wall. The cells are mounted such that, in one embodiment, the substrate surface serves as a sixth side or closure for each cell. Each cell has inside of it a plate, termed the front plate, which is parallel to and in contact with substantially all of the inside surface of the receiving wall. The balance of each cell is completely filled with a projectile-abrading material consisting of glass and a ceramic material and, in certain embodiments, a polymeric material. The glass may be in monolithic form or particles of ceramic may be dispersed in a glass matrix. The ceramic material may be in monolithic form or may be in the form of particles dispersed in glass or dispersed in said polymer.

  4. Hypercube matrix computation task

    NASA Technical Reports Server (NTRS)

    Calalo, R.; Imbriale, W.; Liewer, P.; Lyons, J.; Manshadi, F.; Patterson, J.

    1987-01-01

    The Hypercube Matrix Computation (Year 1986-1987) task investigated the applicability of a parallel computing architecture to the solution of large scale electromagnetic scattering problems. Two existing electromagnetic scattering codes were selected for conversion to the Mark III Hypercube concurrent computing environment. They were selected so that the underlying numerical algorithms utilized would be different thereby providing a more thorough evaluation of the appropriateness of the parallel environment for these types of problems. The first code was a frequency domain method of moments solution, NEC-2, developed at Lawrence Livermore National Laboratory. The second code was a time domain finite difference solution of Maxwell's equations to solve for the scattered fields. Once the codes were implemented on the hypercube and verified to obtain correct solutions by comparing the results with those from sequential runs, several measures were used to evaluate the performance of the two codes. First, a comparison was provided of the problem size possible on the hypercube with 128 megabytes of memory for a 32-node configuration with that available in a typical sequential user environment of 4 to 8 megabytes. Then, the performance of the codes was anlyzed for the computational speedup attained by the parallel architecture.

  5. Hybridized polymer matrix composites

    NASA Technical Reports Server (NTRS)

    House, E. E.; Hoggatt, J. T.; Symonds, W. A.

    1980-01-01

    The extent to which graphite fibers are released from resin matrix composites that are exposed to fire and impact conditions was determined. Laboratory simulations of those conditions that could exist in the event of an aircraft crash and burn situation were evaluated. The effectiveness of various hybridizing concepts in preventing this release of graphite fibers were also evaluated. The baseline (i.e., unhybridized) laminates examined were prepared from commercially available graphite/epoxy, graphite/polyimide, and graphite/phenolic materials. Hybridizing concepts investigated included resin fillers, laminate coatings, resin blending, and mechanical interlocking of the graphite reinforcement. The baseline and hybridized laminates' mechanical properties, before and after isothermal and humidity aging, were also compared. It was found that a small amount of graphite fiber was released from the graphite/epoxy laminates during the burn and impact conditions used in this program. However, the extent to which the fibers were released is not considered a severe enough problem to preclude the use of graphite reinforced composites in civil aircraft structure. It also was found that several hybrid concepts eliminated this fiber release. Isothermal and humidity aging did not appear to alter the fiber release tendencies.

  6. Emergency Response Synchronization Matrix

    Energy Science and Technology Software Center (ESTSC)

    1999-06-01

    An emergency response to a disaster is complex, requiring the rapid integration, coordination, and synchronization of multiple levels of governmental and non-governmental organizations from numerous jurisdictions into a unified community response. For example, a community’s response actions to a fixed site hazardous materials incident could occur in an area extending from an on-site storage location to points 25 or more miles away. Response actions are directed and controlled by local governments and agencies situated withinmore » the response area, as well as by state and federal operaticns centers quite removed from the area of impact. Time is critical and the protective action decision-making process is greatly compressed. The response community must carefully plan and coordinate response operations in order to have confidence that they will be effectively implemented when faced with the potentially catastrophic nature of such releases. A graphical depiction of the entire response process via an emergency response synchronization matrix is an effective tool in optimizing the planning, exercising, and implementation of emergency plans. This system—based approach to emergency planning depicts how a community organizes its response tasks across space and time in relation to hazard actions. It provides the opportunity to make real—time adjustments as necessary for maximizing the often limited resources in protecting area residents. A response must involve the entire community and must not be limited by individual jurisdictions and organizations acting on their own without coordination, integration, and synchronization.« less

  7. Characterization of Protein Structural Changes in Living Cells Using Time-Lapsed FTIR Imaging

    PubMed Central

    Gelfand, Paul; Smith, Randy J.; Stavitski, Eli; Borchelt, David R.; Miller, Lisa M.

    2015-01-01

    Fourier-transform infrared (FTIR) spectroscopic imaging is a widely used method for studying the chemistry of proteins, lipids, and DNA in biological systems without the need for additional tagging or labeling. This technique can be especially powerful for spatially resolved, temporal studies of dynamic changes such as in vivo protein folding in cell culture models. However, FTIR imaging experiments have typically been limited to dry samples as a result of the significant spectral overlap between water and the protein Amide I band centered at 1650 cm−1. Here, we demonstrate a method to rapidly obtain high quality FTIR spectral images at submicron pixel resolution in vivo over a duration of 18 h and longer through the development and use of a custom-built, demountable, microfluidic-incubator and a FTIR microscope coupled to a focal plane array (FPA) detector and a synchrotron light source. The combined system maximizes ease of use by allowing a user to perform standard cell culture techniques and experimental manipulation outside of the microfluidic-incubator, where assembly can be done just before the start of experimentation. The microfluidic-incubator provides an optimal path length of 6–8 μm and a submillimeter working distance in order to obtain FTIR images with 0.54–0.77 μm pixel resolution. In addition, we demonstrate a novel method for the correction of spectral distortions caused by varying concentrations of water over a subconfluent field of cells. Lastly, we use the microfluidic-incubator and time-lapsed FTIR imaging to determine the misfolding pathway of mutant copper–zinc superoxide dismutase (SOD1), the protein known to be a cause of familial amyotrophic lateral sclerosis (FALS). PMID:25965274

  8. Altitude troposphere ozone profiles over Kyiv-Goloseyev station by simultaneous Umkehr and FTIR observations

    NASA Astrophysics Data System (ADS)

    Milinevsky, Gennadi; Shavrina, Angelina; Udodov, Evgeny; Liptuga, Anatoly; Kyslyi, Volodymyr; Danylevsky, Vassyl; Kravchenko, Volodymyr; Ivanov, Yuri; Synyavski, Ivan; Romanyuk, Yaroslav; Pavlenko, Yakov; Veles, Oleksandr

    2016-04-01

    Total ozone column and ozone profile data have been obtained from both: (1) standard Dobson measurements and Umkehr method, and (2) using modeling of the ozone absorption spectral band profile near 9.6 microns with the MODTRAN4.3 Atmospheric Radiation Transfer Model based on the HITRAN molecular absorption database from Fourier transform infrared spectroscopy (FTIR) observations. The simultaneous ground-based Dobson/Umkehr and FTIR ozone observations have been performed in 2014-2015 at the mid-latitude Kyiv-Goloseyev KGV GAW station for joint altitude troposphere ozone profiles analysis. To retrieve ozone column estimates and ozone profiles from FTIR observations, we used the satellite Aqua-AIRS water vapor, temperature and ozone profiles, and the simultaneous with FTIR observations the Umkehr ozone profiles and surface ozone measurements as input a priori information for the MODTRAN4.3 model. The altitude ozone profiles retrieved from Umkehr method and satellite measurements are in good correspondence in stratosphere layer. However the troposphere part of ozone profiles is uncertain and reproduced with large errors. Therefore we use the MODTRAN4.3 model for interpretation of observed FTIR absorption spectrum to retrieve and improve the troposphere part of ozone altitude distribution. The synergy of Umkehr, satellite and FTIR simultaneous observations including surface ozone measurements allows rendering the ozone profile features in troposphere that indicate the stratosphere-troposphere exchange processes. Season ozone profile variations observed from Umkehr measurements are discussed as well. This work was partly supported by the Polar FORCeS project no. 4012 of the Australian Antarctic Science Program.

  9. Automated species and strain identification of bacteria in complex matrices using FTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Puzey, K. A.; Gardner, P. J.; Petrova, V. K.; Donnelly, C. W.; Petrucci, G. A.

    2008-04-01

    Fourier Transform Infrared (FTIR) spectroscopy provides a highly selective and reproducible means for the chemically-based discrimination of intact microbial cells which make the method valuable for large-scale screening of foods. The goals of the present study were to assess the effect of chemical interferents, such as food matrices, different sanitizing compounds and growth media, on the ability of the method to accurately identify and classify L. innocua, L. welshimeri, E. coli, S. cholerasuis, S. subterranea, E. sakazakii, and E. aerogenes. Moreover, the potential of FTIR spectroscopy for discrimination of L. innocua and L. welshimeri of different genotypes and the effect of growth phase on identification accuracy of L. innocua and L. welshimeri were tested. FTIR spectra were collected using two different sample presentation techniques - transmission and attenuated total reflection (ATR), and then analyzed using multivariate discriminant analysis based on the first derivative of the FTIR spectra with the unknown spectra assigned to the species group with the shortest Mahalanobis distance. The results of the study demonstrated 100% correct identification and differentiation of all bacterial strains used in this study in the presence of chemical interferents or food matrices, better than 99% identification rate in presence of media matrices, and 100% correct detection for specific bacteria in mixed flora species. Additionally, FTIR spectroscopy proved to be 100% accurate when differentiating between genotypes of L. innocua and L. welshimeri, with the classification accuracy unaffected by the growth stage. These results suggest that FTIR spectroscopy can be used as a valuable tool for identifying pathogenic bacteria in food and environmental samples.

  10. The large-scale influence of the Great Barrier Reef matrix on wave attenuation

    NASA Astrophysics Data System (ADS)

    Gallop, Shari L.; Young, Ian R.; Ranasinghe, Roshanka; Durrant, Tom H.; Haigh, Ivan D.

    2014-12-01

    Offshore reef systems consist of individual reefs, with spaces in between, which together constitute the reef matrix. This is the first comprehensive, large-scale study, of the influence of an offshore reef system on wave climate and wave transmission. The focus was on the Great Barrier Reef (GBR), Australia, utilizing a 16-yr record of wave height from seven satellite altimeters. Within the GBR matrix, the wave climate is not strongly dependent on reef matrix submergence. This suggests that after initial wave breaking at the seaward edge of the reef matrix, wave energy that penetrates the matrix has little depth modulation. There is no clear evidence to suggest that as reef matrix porosity (ratio of spaces between individual reefs to reef area) decreases, wave attenuation increases. This is because individual reefs cast a wave shadow much larger than the reef itself; thus, a matrix of isolated reefs is remarkably effective at attenuating wave energy. This weak dependence of transmitted wave energy on depth of reef submergence, and reef matrix porosity, is also evident in the lee of the GBR matrix. Here, wave conditions appear to be dependent largely on local wind speed, rather than wave conditions either seaward, or within the reef matrix. This is because the GBR matrix is a very effective wave absorber, irrespective of water depth and reef matrix porosity.

  11. Fourier Transform Infrared Spectroscopy to Quantify Collagen and Elastin in an In Vitro Model of Extracellular Matrix Degradation in Aorta

    PubMed Central

    Cheheltani, Rabee; McGoverin, Cushla M.; Rao, Jayashree; Vorp, David A.; Kiani, Mohammad F.; Pleshko, N.

    2014-01-01

    Extracellular matrix (ECM) is a key component and regulator of many biological tissues including aorta. Several aortic pathologies are associated with significant changes in the composition of the matrix, especially in the content, quality and type of aortic structural proteins, collagen and elastin. The purpose of this study was to develop an infrared spectroscopic methodology that is comparable to biochemical assays to quantify collagen and elastin in aorta. Enzymatically degraded porcine aorta samples were used as a model of ECM degradation in abdominal aortic aneurysm (AAA). After enzymatic treatment, Fourier transform infrared (FTIR) spectra of the aortic tissue were acquired by an infrared fiber optic probe (IFOP) and FTIR imaging spectroscopy (FT-IRIS). Collagen and elastin content were quantified biochemically and partial least squares (PLS) models were developed to predict collagen and elastin content in aorta based on FTIR spectra. PLS models developed from FT-IRIS spectra were able to predict elastin and collagen content of the samples with strong correlations (RMSE of validation = 8.4% and 11.1% of the range respectively), and IFOP spectra were successfully used to predict elastin content (RMSE = 11.3% of the range). The PLS regression coefficients from the FT-IRIS models were used to map collagen and elastin in tissue sections of degraded porcine aortic tissue as well as a human AAA biopsy tissue, creating a similar map of each component compared to histology. These results support further application of FTIR spectroscopic techniques for evaluation of AAA tissues. PMID:24761431

  12. Water Structure Studied by Far Infrared Spectroscopy in FTIR Beam Line of MIRRORCLE 20

    SciTech Connect

    Miura, Nobuhiro; Moon, Ahsa; Kitagawa, Toshimichi; Yamada, Hironari

    2007-03-30

    Far infrared vibrational Spectroscopy for distilled water was performed by Fourier Transform Infrared Spectroscopy (FT-IR) in the FTIR beam line of MIRRORCLE 20. Synchrotron radiation was utilized as a light source for the absorption Spectroscopy in the frequency range from 100cm-1 to 20cm-1. Off-line measurements by black body radiation of ceramic heater were also examined in the range from 400cm-1 to 50cm-1. Wide range spectrum was obtained after the SR data merged the off-line data. We report the recent development in the beam line and the examples of spectra related to the water structure.

  13. Characterisation Of Polysacharides And Lipids From Selected Green Algae Species By FTIR-ATR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Bartošová, Alica; Blinová, Lenka; Gerulová, Kristína

    2015-06-01

    Fourier transform infrared (FTIR) spectroscopy was used in this study to identify and determine spectral features of Chromochloris zofingiensis (Dönz) Fucíková et L.A. Lewis (SAG 211-14, Gottingen, Germany), Acutodesmus obliguus (Turpin) Hegewald (SAG 276-1, Gottingen, Germany) and Chlorella sorokiniana (K. Brandt) Pröschold et Darienko (SAG 211-40c, Gottingen, Germany). Polysaccharides and lipids from these three algae species were determined using Fourier Transformed Infrared Spectroscopy (FTIR) with ATR accessory with diamante crystal in spectral range from 400 - 4000 cm-1 and resolution 4.

  14. [Using barium fluoride fine particles as stationary phase for TLC/FTIR analysis].

    PubMed

    Liu, Xi; Pan, Qing-hua; Ding, Jie; Zhu, Qing; He, An-qi; Yue, Shi-juan; Li, Xiao-pei; Hu, Li-ping; Xia, Jin-ming; Liu, Cui-ge; Wei, Yong-ju; Yu, Jiang; Yang, Zhan-lan; Zhu, Xi; Xu, Yi-zhuang; Wu, Jin-guang

    2011-07-01

    In situ TLC/FTIR technique has tremendous potential in the analysis of complex mixtures. However, the progress in this technique was quite slow. The reason is that conventional stationary phase such as silica gel etc. has strong absorption in FTIR spectrum and thus brings about severe interference in the detection of samples. To solve the problem, the authors propose to use barium fluoride fine particles as stationary phase of TLC plate. The reasons are as follows: Barium fluoride wafer has been extensively used as infrared window in FTIR experiments and it has no absorbance in an IR region between 4 000 and 800 cm'. As a matter of fact, the atomic mass of barium and fluoride is quite large, thus the normal vibration of BaF2 lattice is limited in far-IR region and low frequency part of mid-IR region. Therefore, the interference caused by IR absorption of stationary phase can be resolved if BaF2 is used as stationary phase of TLC plate. Moreover, BaF2 is quite stable and insolvable in water and most organic solvents and it will not be dissolved by mobile phase or react with samples in TLC separation. Additionally, decreasing the particle size of BaF2 is very important in TLC/FTIR analysis technique. The reason is two-fold: First, decreasing the particle size of stationary phase is helpful to improving the efficiency of separation by TLC plate; second, decreasing the size of BaFz particle can improve the quality of FTIR spectra by alleviating the problem of light scattering. By optimizing the synthetic conditions, fine particles of barium fluoride were obtained. SEM results indicate that the size of the BaF2 particles is around 500 nm. FTIR spectrum of the BaF2 particles shows that no absorption of impurity was observed. Moreover, the elevation of baseline caused by light scattering is insignificant. The authors have developed a new technique named "settlement volatilization method" to prepare TLC plate without polymeric adhesive that may bring about significant

  15. Water Structure Studied by Far Infrared Spectroscopy in FTIR Beam Line of MIRRORCLE 20

    NASA Astrophysics Data System (ADS)

    Miura, Nobuhiro; Moon, Ahsa; Yamada, Hironari; Kitagawa, Toshimichi

    2007-03-01

    Far infrared vibrational Spectroscopy for distilled water was performed by Fourier Transform Infrared Spectroscopy (FT-IR) in the FTIR beam line of MIRRORCLE 20. Synchrotron radiation was utilized as a light source for the absorption Spectroscopy in the frequency range from 100cm-1 to 20cm-1. Off-line measurements by black body radiation of ceramic heater were also examined in the range from 400cm-1 to 50cm-1. Wide range spectrum was obtained after the SR data merged the off-line data. We report the recent development in the beam line and the examples of spectra related to the water structure.

  16. IRIS: A database application system for diseases identification using FTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Arshad, Ahmad Zulhilmi; Munajat, Yusof; Ibrahim, Raja Kamarulzaman Raja; Mahmood, Nasrul Humaimi

    2015-05-01

    Infrared information on diseases identification system (IRIS) is an application for diseases identification and analysis by using Fourier transform infrared (FTIR) spectroscopy. This is the preliminary step to gather information from the secondary data which was extracted from recognized various research and scientific paper, which are combined into a single database as in IRIS for our purpose of study. The importance of this database is to examine the fingerprint differences between normal and diseases cell or tissue. With the implementation of this application is it hopes that the diseases identification using FTIR spectroscopy would be more reliable and may assist either physicians, pathologists, or researchers to diagnose the certain type of disease efficiently.

  17. Ceramic matrix composite article and process of fabricating a ceramic matrix composite article

    DOEpatents

    Cairo, Ronald Robert; DiMascio, Paul Stephen; Parolini, Jason Robert

    2016-01-12

    A ceramic matrix composite article and a process of fabricating a ceramic matrix composite are disclosed. The ceramic matrix composite article includes a matrix distribution pattern formed by a manifold and ceramic matrix composite plies laid up on the matrix distribution pattern, includes the manifold, or a combination thereof. The manifold includes one or more matrix distribution channels operably connected to a delivery interface, the delivery interface configured for providing matrix material to one or more of the ceramic matrix composite plies. The process includes providing the manifold, forming the matrix distribution pattern by transporting the matrix material through the manifold, and contacting the ceramic matrix composite plies with the matrix material.

  18. Synthetic Division and Matrix Factorization

    ERIC Educational Resources Information Center

    Barabe, Samuel; Dubeau, Franc

    2007-01-01

    Synthetic division is viewed as a change of basis for polynomials written under the Newton form. Then, the transition matrices obtained from a sequence of changes of basis are used to factorize the inverse of a bidiagonal matrix or a block bidiagonal matrix.

  19. How to Study a Matrix

    ERIC Educational Resources Information Center

    Jairam, Dharmananda; Kiewra, Kenneth A.; Kauffman, Douglas F.; Zhao, Ruomeng

    2012-01-01

    This study investigated how best to study a matrix. Fifty-three participants studied a matrix topically (1 column at a time), categorically (1 row at a time), or in a unified way (all at once). Results revealed that categorical and unified study produced higher: (a) performance on relationship and fact tests, (b) study material satisfaction, and…

  20. Formulation and evaluation of olanzapine matrix pellets for controlled release

    PubMed Central

    Vishal Gupta, N.; Balamuralidhara, V.; Mohammed Khan, S.

    2011-01-01

    Background and the purpose of the study Olanzapine is an antipsychotic used in treatment of schizophrenia. This research was carried out to design oral controlled release matrix pellets of water insoluble drug Olanzapine (OZ), using blend of Sodium Alginate (SA) and Glyceryl Palmito-Stearate (GPS) as matrix polymers, micro crystalline cellulose (MCC) as spheronizer enhancer and Sodium Lauryl Sulphate (SLS) as pore forming agent. Methods OZ formulations were developed by the pelletization technique by drug loaded pellets and characterized with regard to the drug content, size distribution, Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction study (XRD). Stability studies were carried out on the optimized formulation for a period of 90 days at 40±2 °C and 75±5% relative humidity. Results and major conclusion The drug content was in the range of 93.34–98.12%. The mean particle size of the drug loaded pellets was in the range 1024 to 1087µm. SEM photographs and calculated sphericity factor confirmed that the prepared formulations were spherical in nature. The compatibility between drug and polymers in the drug loaded pellets was confirmed by DSC and FTIR studies. Stability studies indicated that pellets are stable. XRD patterns revealed the crystalline nature of the pure OZ. Loose surface crystal study indicated that crystalline OZ is present in all formulations and more clear in formulation F5. Drug release was controlled for more than 24 hrs and mechanism of the drug release followed by Fickian diffusion. It may be concluded that F5 is an ideal formulation for once a day administration. PMID:22615665