Sample records for reaction ir 1h

  1. Competing reaction channels in IR-laser-induced unimolecular reactions

    SciTech Connect

    Berman, M.R.

    1981-01-01

    The competing reaction channels in the unimolecular decomposition of two molecules, formaldehyde and tetralin were studied. A TEA CO/sub 2/ laser was used as the excitation source in all experiments. The dissociation of D/sub 2/CO was studied by infrared multiphoton dissociation (MPD) and the small-molecule nature of formaldehyde with regard to MPD was explored. The effect of collisions in MPD were probed by the pressure dependence of the MPD yield and ir fluorescence from multiphoton excited D/sub 2/CO. MPD yield shows a near cubic dependence in pure D/sub 2/CO which is reduced to a 1.7 power dependence when 15 torr of NO is added. The peak amplitude of 5 ..mu..m ir fluorescence from D/sub 2/CO is proportional to the square of the D/sub 2/CO pressure in pure D/sub 2/CO or in the presence of 50 torr of Ar. Results are explained in terms of bottlenecks to excitation at the v = 1 level which are overcome by a combination of vibrational energy transfer and rotational relaxation. The radical/molecule branching ratio in D/sub 2/CO MPD was 0.10 +- 0.02 at a fluence of 125 J/cm/sup 2/ at 946.0 cm/sup -1/. The barrier height to molecular dissociation was calculated to be 3.6 +- 2.0 kcal/mole below the radical threshold or 85.0 +- 3.0 kcal/mole above the ground state of D/sub 2/CO. In H/sub 2/CO, this corresponds to 2.5 +- 2.0 kcal/mole below the radical threshold or 83.8 +- 3.0 kcal/mole above the ground state. Comparison with uv data indicate that RRKM theory is an acceptable description of formaldehyde dissociation in the 5 to 10 torr pressure range. The unimolecular decomposition of tetralin was studied by MPD and SiF/sub 4/ - sensitized pyrolysis. Both techniques induce decomposition without the interference of catalytic surfaces. Ethylene loss is identified as the lowest energy reaction channel. Dehydrogenation is found to result from step-wise H atom loss. Isomerization via disproportionation is also identified as a primary reaction channel.

  2. A classical approach in simple nuclear fusion reaction {sub 1}H{sup 2}+{sub 1}H{sup 3} using two-dimension granular molecular dynamics model

    SciTech Connect

    Viridi, S.; Kurniadi, R.; Waris, A.; Perkasa, Y. S. [Nuclear Physics and Biophysics Research Division, Institut Teknologi Bandung, Bandung 40132 (Indonesia); Doctoral Program in Physics, Institut Teknologi Bandung, Bandung 40132 Physics Department, Universitas Islam Negeri Sunan Gunung Djati, Bandung 40614 (Indonesia)

    2012-06-06

    Molecular dynamics in 2-D accompanied by granular model provides an opportunity to investigate binding between nuclei particles and its properties that arises during collision in a fusion reaction. A fully classical approach is used to observe the influence of initial angle of nucleus orientation to the product yielded by the reaction. As an example, a simplest fusion reaction between {sub 1}H{sup 2} and {sub 1}H{sup 3} is observed. Several products of the fusion reaction have been obtained, even the unreported ones, including temporary {sub 2}He{sup 4} nucleus.

  3. FT-IR and {sup 1}H NMR characterization of the products of an ethylene inverse diffusion flame

    SciTech Connect

    Santamaria, Alexander; Mondragon, Fanor [Institute of Chemistry, University of Antioquia, A.A. 1226, Medellin (Colombia); Molina, Alejandro [Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551 (United States); Marsh, Nathan D.; Eddings, Eric G.; Sarofim, Adel F. [Department of Chemical Engineering, University of Utah, Salt Lake City, UT 84112 (United States)

    2006-07-15

    Knowledge of the chemical structure of young soot and its precursors is very useful in the understanding of the paths leading to soot particle inception. This paper presents analyses of the chemical functional groups, based on FT-IR and {sup 1}H NMR spectroscopy of the products obtained in an ethylene inverse diffusion flame. The trends in the data indicate that the soluble fraction of the soot becomes progressively more aromatic and less aliphatic as the height above the burner increases. Results from {sup 1}H NMR spectra of the chloroform-soluble soot samples taken at different heights above the burner corroborate the infrared results based on proton chemical shifts (Ha, H{alpha}, H{beta}, and H{gamma}). The results indicate that the aliphatic {beta} and {gamma} hydrogens suffered the most drastic reduction, while the aromatic character increased considerably with height, particularly in the first half of the flame. (author)

  4. Synthesis, IR, UV\\/vis-, 1H NMR and DFT study of chelatophore functionalized 1,3-benzoxazinone spiropyrans

    Microsoft Academic Search

    Antony O. Bulanov; Leonid D. Popov; Igor N. Shcherbakov; Victor A. Kogan; Valerii A. Barachevsky; Vladimir V. Lukov; S. N. Borisenko; Yu. N. Tkachenko

    2008-01-01

    Six novel functionalized spiropyran's derivatives of 2H-1,3-benzoxazinone series were synthesized by introducing the substituents with chelating ability into 2H-chromene part of the 8?-formyl-7?-hydroxy-3-methyl-4-oxo-3,4-dihydro-2H-1,3-benzoxazine-2-spiro-2?-[2H]-chromene (I) by condensation with 2-aminophenol, 2-amino-4-methylphenol, 2-amino-4-nitrophenol, 2-amino-1-methylbenzimidazole, 4-amino-4H-1,2,4-triazole, N-(4-aminophenyl)acetamide. 1H NMR, UV\\/vis, IR spectroscopy combined with quantum-chemical calculations employing density functional theory (DFT) were used to study their structure. All substances, except 2-amino-4-nitrophenol derivative exist in

  5. Organocatalyzed enantioselective aldol reaction of 1H-pyrrole-2,3-diones

    PubMed Central

    Bhanushali, Mayur

    2011-01-01

    The enantioselective cross aldol reaction of 1-benzyl 4,5-dioxo-2-aryl-4,5-dihydro-1H-pyrrole-3-carboxylates and ketones was studied with proline derivatives or cinchona alkaloid-derived primary amines as the catalysts for the first time. trans-4-Benzoyloxy-L-proline (15) was found to be the best catalyst for acyclic ketones. For cyclohexanone, the best results were achieved with 9-deoxy-9-epi-aminoquinine (18) as the catalyst in the presence of racemic 1,1'-binaphthyl-2,2'-diyl hydrogen phosphate (19) as the cocatalyst. Using these protocols, 3-alkyl-3-hydroxy-1H-pyrrol-2(3H)-one derivatives were obtained in excellent yields and good to high ee values (up to 94% ee). PMID:22544980

  6. Reversed-phase HPLC of polymer additives with multiple on-line spectroscopic analysis (UV, IR, (1)H NMR and MS).

    PubMed

    Louden, Dave; Handley, Alan; Lenz, Eva; Sinclair, Ian; Taylor, Steve; Wilson, Ian D

    2002-07-01

    The reversed-phase chromatography of a number of polymer additives has been undertaken with on-line characterisation via a combination of diode array UV, (1)H NMR, IR spectroscopy and mass spectrometry. This combination of spectrometers enabled the on-flow collection of full UV, (1)H NMR, IR and mass spectra for a range of common polymer additives in amounts ranging from ca. 230 to 900 micro g on-column. The practical difficulties associated with multiple hyphenation and potential future developments are discussed. PMID:12172686

  7. Simultaneous 19F-1H medium resolution NMR spectroscopy for online reaction monitoring

    NASA Astrophysics Data System (ADS)

    Zientek, Nicolai; Laurain, Clément; Meyer, Klas; Kraume, Matthias; Guthausen, Gisela; Maiwald, Michael

    2014-12-01

    Medium resolution nuclear magnetic resonance (MR-NMR) spectroscopy is currently a fast developing field, which has an enormous potential to become an important analytical tool for reaction monitoring, in hyphenated techniques, and for systematic investigations of complex mixtures. The recent developments of innovative MR-NMR spectrometers are therefore remarkable due to their possible applications in quality control, education, and process monitoring. MR-NMR spectroscopy can beneficially be applied for fast, non-invasive, and volume integrating analyses under rough environmental conditions. Within this study, a simple 1/16? fluorinated ethylene propylene (FEP) tube with an ID of 0.04? (1.02 mm) was used as a flow cell in combination with a 5 mm glass Dewar tube inserted into a benchtop MR-NMR spectrometer with a 1H Larmor frequency of 43.32 MHz and 40.68 MHz for 19F. For the first time, quasi-simultaneous proton and fluorine NMR spectra were recorded with a series of alternating 19F and 1H single scan spectra along the reaction time coordinate of a homogeneously catalysed esterification model reaction containing fluorinated compounds. The results were compared to quantitative NMR spectra from a hyphenated 500 MHz online NMR instrument for validation. Automation of handling, pre-processing, and analysis of NMR data becomes increasingly important for process monitoring applications of online NMR spectroscopy and for its technical and practical acceptance. Thus, NMR spectra were automatically baseline corrected and phased using the minimum entropy method. Data analysis schemes were designed such that they are based on simple direct integration or first principle line fitting, with the aim that the analysis directly revealed molar concentrations from the spectra. Finally, the performance of 1/16? FEP tube set-up with an ID of 1.02 mm was characterised regarding the limit of detection (LOQ (1H) = 0.335 mol L-1 and LOQ (19F) = 0.130 mol L-1 for trifluoroethanol in D2O (single scan)) and maximum quantitative flow rates up to 0.3 mL min-1. Thus, a series of single scan 19F and 1H NMR spectra acquired with this simple set-up already presents a valuable basis for quantitative reaction monitoring.

  8. Simultaneous (19)F-(1)H medium resolution NMR spectroscopy for online reaction monitoring.

    PubMed

    Zientek, Nicolai; Laurain, Clément; Meyer, Klas; Kraume, Matthias; Guthausen, Gisela; Maiwald, Michael

    2014-10-18

    Medium resolution nuclear magnetic resonance (MR-NMR) spectroscopy is currently a fast developing field, which has an enormous potential to become an important analytical tool for reaction monitoring, in hyphenated techniques, and for systematic investigations of complex mixtures. The recent developments of innovative MR-NMR spectrometers are therefore remarkable due to their possible applications in quality control, education, and process monitoring. MR-NMR spectroscopy can beneficially be applied for fast, non-invasive, and volume integrating analyses under rough environmental conditions. Within this study, a simple 1/16? fluorinated ethylene propylene (FEP) tube with an ID of 0.04? (1.02mm) was used as a flow cell in combination with a 5mm glass Dewar tube inserted into a benchtop MR-NMR spectrometer with a (1)H Larmor frequency of 43.32MHz and 40.68MHz for (19)F. For the first time, quasi-simultaneous proton and fluorine NMR spectra were recorded with a series of alternating (19)F and (1)H single scan spectra along the reaction time coordinate of a homogeneously catalysed esterification model reaction containing fluorinated compounds. The results were compared to quantitative NMR spectra from a hyphenated 500MHz online NMR instrument for validation. Automation of handling, pre-processing, and analysis of NMR data becomes increasingly important for process monitoring applications of online NMR spectroscopy and for its technical and practical acceptance. Thus, NMR spectra were automatically baseline corrected and phased using the minimum entropy method. Data analysis schemes were designed such that they are based on simple direct integration or first principle line fitting, with the aim that the analysis directly revealed molar concentrations from the spectra. Finally, the performance of 1/16? FEP tube set-up with an ID of 1.02mm was characterised regarding the limit of detection (LOQ ((1)H)=0.335molL(-1) and LOQ ((19)F)=0.130molL(-1) for trifluoroethanol in D2O (single scan)) and maximum quantitative flow rates up to 0.3mLmin(-1). Thus, a series of single scan (19)F and (1)H NMR spectra acquired with this simple set-up already presents a valuable basis for quantitative reaction monitoring. PMID:25462947

  9. Discovering [superscript 13]C NMR, [superscript 1]H NMR, and IR Spectroscopy in the General Chemistry Laboratory through a Sequence of Guided-Inquiry Exercises

    ERIC Educational Resources Information Center

    Iler, H. Darrell; Justice, David; Brauer, Shari; Landis, Amanda

    2012-01-01

    This sequence of three guided-inquiry labs is designed for a second-semester general chemistry course and challenges students to discover basic theoretical principles associated with [superscript 13]C NMR, [superscript 1]H NMR, and IR spectroscopy. Students learn to identify and explain basic concepts of magnetic resonance and vibrational…

  10. Experimental and quantum chemical study on the IR, UV and electrode potential of 6-(2,3-dihydro-1,3-dioxo-2-phenyl-1 H-inden-2-yl)-2,3-dihydroxybenzaldehyde

    NASA Astrophysics Data System (ADS)

    Riahi, Siavash; Ganjali, Mohammad Reza; Bayandori Moghaddam, Abdolmajid; Norouzi, Parviz

    2008-12-01

    Electrode potential of 6-(2,3-dihydro-1,3-dioxo-2-phenyl-1 H-inden-2-yl)-2,3-dihydroxybenzaldehyde (DPDB) in methanol have been calculated theoretically. For the achievement of this task, the density functional theory (B3LYP/6-31G(d)) was employed with the inclusion of the entropic and thermochemical corrections to yield the free energies of the redox reactions. The electrode potential was also obtained experimentally by means of an electrochemical technique (cyclic voltammetry). The geometric parameters, the vibrational frequency values and the UV spectrum of DPDB and 2-(2,3-dihydro-1,3-dioxo-2-phenyl-1 H-inden-2-yl)-5,6-dioxocyclohexa-1,3-dienecarbaldehyde (DPDD is the oxidized form of DPDB), were computed using the same methods. The calculated IR spectrum of DPDB, used for the assignment of the IR frequencies, was observed in the experimental FT-IR spectrum. The correlation between the theoretical and experimental DPDB vibrational frequencies was 0.996. This agreement mutually verified the accuracy of the experimental method and the validity of the applied mathematical model.

  11. Molecular structures of 3,6-di(hexylthioureido)acridine conformers, their protonation, 1H NMR and IR analyses: Theoretical and experimental studies

    NASA Astrophysics Data System (ADS)

    Keawwangchai, Somchai; Tuntulani, Thawatchai; Ruangpornvisuti, Vithaya

    2007-04-01

    The optimized structures of the 3,6-di(hexylthioureido)acridine conformers were obtained using density functional theory (DFT) and ONIOM methods. Three conformers of 3,6-di(hexylthioureido)acridine and their corresponding protonated forms were found. Single-point energies calculations were obtained using second-order Møller-Plesset at the MP2(fc)/6-31G(d) level. The computed 1H NMR chemical shifts referenced to TMS in DMSO for all conformers were obtained. The presence of symmetrical conformers of the neutral and protonated structures were confirmed by the 1H NMR measurement. The measured and computed IR spectra of the neutral and protonated species of 3,6-di(hexylthioureido)acridine were obtained and compared.

  12. Extremely strong temperature-dependent Davydow-splitting effects in the polarized IR spectra of the hydrogen bond: Pyrazole and quinolin-2(1H)-one crystals

    NASA Astrophysics Data System (ADS)

    Hachu?a, Barbara; Flakus, Henryk T.; Tyl, Aleksandra; Polasz, Anna

    2014-04-01

    Polarized IR spectra were recorded in the spectral range of the ?N-H and ?N-D proton stretching vibration bands for the isotopically neat and isotopically diluted crystals of pyrazole (Pzl) and quinolin-2(1H)-one (2HQ). The spectra measured in the temperature range of 77-293 K have shown that temperature extremely strongly influenced the magnitude of the Davydow-splitting effects in the crystalline spectra. Two different competing vibrational Davydow-coupling mechanisms involving hydrogen bonds, i.e., the ‘tail-to-head' and the ‘side-to-side', were responsible for the generation of the temperature effects in the polarized spectra.

  13. 1H NMR of albumin in human blood plasma: drug binding and redox reactions at Cys 34

    Microsoft Academic Search

    John Christodoulou; Peter J. Sadler; Alan Tucker

    1995-01-01

    1H NMR methods are described which allow direct studies of the Cys34 binding site of albumin in intact human blood plasma in vitro. Antiarthritic gold drugs and the alcohol-aversive drug disulfiram induce a structural transition detectable via H?1 and H?2 resonances of His3 of albumin, and reactions of cystine, glutathione and captopril in plasma have also been investigated. Contrary to

  14. FT-IR, FT-Raman, dispersive Raman, NMR spectroscopic studies and NBO analysis of 2-Bromo-1H-Benzimidazol by density functional method

    NASA Astrophysics Data System (ADS)

    Sas, E. B.; Kurt, M.; Karabacak, M.; Poiyamozhi, A.; Sundaraganesan, N.

    2015-02-01

    In this study, geometrical optimization, FT-IR (4000-400 cm-1), FT-Raman (4000-40 cm-1), dispersive Raman (4000-40 cm-1) spectroscopic analysis, electronic structure and 1H and 13C nuclear magnetic resonance (NMR) studies of 2-Bromo-1H-Benzimidazol (abbreviated as 2Br1HB) were undertaken by utilizing DFT/B3LYP with 6-311+G(d,p) basis set. The results of the calculations were applied to simulate spectra of the title compound, which show good agreement with observed spectra. Complete vibrational assignments, analysis and correlations of the fundamental modes for 2Br1HB compound were carried out. Stability of the molecule arising from hyperconjugative interactions, charge delocalization was analyzed using natural bond orbital (NBO) analysis. The molecule orbital contributions were studied by using the total density of states (TDOS), partial density of states (PDOS), and overlap population density of states (OPDOS). The electronic properties like HOMO-LUMO energies and molecular electrostatic potential (MEP) analysis were reported. The calculated HOMO and LUMO energies shows that charge transfer interactions take place within the molecule. Mulliken population analysis on atomic charges was also calculated. Good correlation between the experimental 1H and 13C NMR chemical shifts in DMSO solution and calculated gauge-including atomic orbital (GIAO) shielding tensors were found.

  15. Structural study of 2-(1-oxo-1 H-inden-3-yl)-2 H-indene-1,3-dione by DFT calculations, NMR and IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Riahi, Siavash; Ganjali, Mohammad Reza; Moghaddam, Abdolmajid Bayandori; Norouzi, Parviz; Hosseiny Davarani, Saied Saeed

    2008-06-01

    Computational studies have been carried out at the DFT-B3LYP/6-31G(d) level of theory on the structural and spectroscopic properties of 2-(1-oxo-1 H-inden-3-yl)-2 H-indene-1,3-dione (OID). Experimental studies were conducted on these parameters, including X-ray, FT-IR and 13C NMR spectroscopy. The optimized geometries of OID and its bonding characteristics as well as IR and NMR spectra have been calculated and analyzed. It was observed that the bond lengths and angles in the molecule, obtained by X-ray, IR and NMR at the level of theory, were in a good agreement with those of the experiment. The correlation between the theoretical and the experimental vibrational frequencies and the chemical shifts of the OID molecule were 0.994 and 0.991, respectively. The agreement mutually verified the accuracy of the experimental method and the validity of the applied mathematical model.

  16. Iridium porphyrins in CD3OD: reduction of Ir(III), CD3-OD bond cleavage, Ir-D acid dissociation and alkene reactions.

    PubMed

    Bhagan, Salome; Imler, Gregory H; Wayland, Bradford B

    2013-04-15

    Methanol solutions of iridium(III) tetra(p-sulfonatophenyl)porphyrin [(TSPP)Ir(III)] form an equilibrium distribution of methanol and methoxide complexes ([(TSPP)Ir(III)(CD3OD)(2-n)(OCD3)n]((3+n)-)). Reaction of [(TSPP)Ir(III) with dihydrogen (D2) in methanol produces an iridium hydride [(TSPP)Ir(III)-D(CD3OD)](4-) in equilibrium with an iridium(I) complex ([(TSPP)Ir(I)(CD3OD)](5-)). The acid dissociation constant of the iridium hydride (Ir-D) in methanol at 298 K is 3.5 × 10(-12). The iridium(I) complex ([(TSPP)Ir(I)(CD3OD)](5-)) catalyzes reaction of [(TSPP)Ir(III)-D(CD3OD)](4-) with CD3-OD to produce an iridium methyl complex [(TSPP)Ir(III)-CD3(CD3OD)](4-) and D2O. Reactions of the iridium hydride with ethene and propene produce iridium alkyl complexes, but the Ir-D complex fails to give observable addition with acetaldehyde and carbon monoxide in methanol. Reaction of the iridium hydride with propene forms both the isopropyl and propyl complexes with free energy changes (?G° 298 K) of -1.3 and -0.4 kcal mol(-1) respectively. Equilibrium thermodynamics and reactivity studies are used in discussing relative Ir-D, Ir-OCD3 and Ir-CD2- bond energetics in methanol. PMID:23540797

  17. Chapter 3 An Important Well Studied Atmospheric Reaction, O ( D 1 ) + H 2

    Microsoft Academic Search

    João Brandão; Carolina M. A. Rio; Wenli Wang

    2008-01-01

    Among the chemical reactions in atmosphere, the reaction of an excited oxygen atom, O (D1), with ground state molecular hydrogen, H2 (X?g+1), has been one of the most studied both experimentally and theoretically. To describe this reaction, various potential energy surfaces have been calibrated and their dynamics has been studied using quantum mechanical and quasiclassical trajectory methods. The theoretical results

  18. Adducts of organotin(IV), tin(IV) and tin(II) halides with 1-methyl-imidazoline-2(3 H)-thione (Hmimt) and imidazoline-2(1,3 H)-thione (Himt). Synthesis, spectroscopic (IR, Mössbauer and 1H, 13C, 119Sn NMR) studies and in vitro antitumour activity

    Microsoft Academic Search

    Dimitra Kovala-Demertzi; Polymnia Tauridou; Umberto Russo; Marcel Gielen

    1995-01-01

    The reactions of 1-methyl-imidazoline-2(3H)-thione (Hmimt) and imidazoline-2(1,3H)-thione (Himt) with organotin(IV), tin(IV) and tin(II) halides were studied. Ten novel adducts were prepared and characterised by elemental analysis, conductivity measurements, IR, far-IR, 1H NMR, 13C NMR, 119Sn NMR and Mössbauer spectroscopy. The ligands behave as monodentate and exhibit sulfur coordination. The structure of the complexes, in the solid state, is discussed in

  19. FT-IR, FT-Raman and computational study of 1H-2,2-dimethyl-3H-phenothiazin-4[10H]-one

    NASA Astrophysics Data System (ADS)

    Minitha, R.; Sheena Mary, Y.; Varghese, Hema Tresa; Panicker, C. Yohannan; Ravindran, Reena; Raju, K.; Manikantan Nair, V.

    2011-01-01

    FT-IR and FT-Raman spectra of 1H-2,2-dimethyl-3H-phenothiazin-4[10H]-one were recorded and analyzed. The vibrational wavenumbers were computed using HF/6-31G(d) and B3LYP/6-31G(d) basis. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands obtained in infrared and Raman spectroscopies of the studied molecule. The first hyperpolarizability, infrared intensities and Raman activities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of non-linear optics. The geometrical parameters of the title compound are in agreement with XRD crystal structure data. The red shift of the N sbnd H stretching wavenumber in the infrared spectrum from the computed wavenumber indicates the weakening of the N sbnd H bond.

  20. Investigation of the Exclusive {sup 3}He(e,e{sup '}pn){sup 1}H Reaction

    SciTech Connect

    Middleton, D. G.; Grabmayr, P.; Hehl, T.; Heim, J.; Martin, I.; Moschini, F. [Kepler Centre for Astro and Particle Physics, Physikalisches Institut, Universitaet Tuebingen, D-72076 Tuebingen (Germany); Annand, J. R. M.; Glazier, D. I.; MacGregor, I. J. D.; McGeorge, J. C.; Monstad, K.; Rosner, G.; Watts, D. P. [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland (United Kingdom); Antelo, M. Ases; Ayerbe, C.; Baumann, D.; Bermuth, J.; Bernauer, J.; Boehm, R.; Ding, M. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz, D-55099 Mainz (Germany)

    2009-10-09

    Cross sections for the {sup 3}He(e,e{sup '}pn){sup 1}H reaction were measured for the first time at energy transfers of 220 and 270 MeV for several momentum transfers ranging from 300 to 450 MeV/c. Cross sections are presented as a function of the momentum of the recoil proton and the momentum transfer. Continuum Faddeev calculations using the Argonne V18 and Bonn-B nucleon-nucleon potentials overestimate the measured cross sections by a factor 5 at low recoil proton momentum with the discrepancy becoming smaller at higher recoil proton momentum.

  1. IR Spectroscopy Method for Determining The Reactivity of Isocyanate Groups in Isophorone Diisocyanate Reactions

    NASA Astrophysics Data System (ADS)

    Dzalmukhanova, A. S.; Lodygina, V. P.; Komratova, V. V.; Karpov, S. V.; Malkov, G. V.; Badamshina, E. R.

    2015-03-01

    We have developed a fast IR spectroscopy method for determining the concentrations of cycloaliphatic and aliphatic isocyanate groups in isophorone diisocyanate that react to form urethanes. It is based on the experimentally established fact that there is a difference between the frequencies of the stretching vibrations for the N-H bond in urethanes formed by cycloaliphatic and aliphatic isocyanate groups in isophorone diisocyanate, when the IR spectra are recorded for dilute solutions of the reaction mixture in carbon tetrachloride. The method can be used to determine the reactivity of isocyanate groups in different reactions involving isophorone diisocyanate.

  2. Proposed model for in vitro interaction between fenitrothion and DNA, by using competitive fluorescence, (31)P NMR, (1)H NMR, FT-IR, CD and molecular modeling.

    PubMed

    Ahmadi, Farhad; Jafari, Batool; Rahimi-Nasrabadi, Mehdi; Ghasemi, Sahar; Ghanbari, Kumars

    2013-03-01

    In this work we proposed a model for in vitro interaction of fenitrothion (FEN) with calf thymus-DNA by combination of multispectroscopic and two dimensional molecular modeling (ONIOM) methods. The circular dichroism results showed that FEN changes the conformation of B-DNA and caused some changes to C-DNA form. The FT-IR results confirmed a partial intercalation between FEN and edges of all base pairs. The competitive fluorescence, using methylene blue as fluorescence probe, in the presence of increasing amounts of FEN, revealed that FEN is able to release the non-intercalated methylene blue from the DNA. The weak chemical shift and peak broadening of (1)H NMR spectrum of FEN in the presence of DNA confirmed a non-intercalation mode. The (31)P NMR showed that FEN interacts more with DNA via its -NO2 moiety. The ONIOM, based on the hybridization of QM/MM (DFT, 6.31++G (d,p)/UFF) methodology, was also performed by Gaussian 2003 package. The results revealed that the interaction is base sequence dependent, and FEN interacts more with AT base sequences. PMID:23153512

  3. Synthesis of 3,4-dihydro-1,8-naphthyridin-2(1H)-ones via microwave-activated inverse electron-demand Diels–Alder reactions

    PubMed Central

    Fadel, Salah; Hajbi, Youssef; Khouili, Mostafa; Lazar, Said

    2014-01-01

    Summary Substituted 3,4-dihydro-1,8-naphthyridin-2(1H)-ones have been synthesized with the inverse electron-demand Diels–Alder reaction from 1,2,4-triazines bearing an acylamino group with a terminal alkyne side chain. Alkynes were first subjected to the Sonogashira cross-coupling reaction with aryl halides, the product of which then underwent an intramolecular inverse electron-demand Diels–Alder reaction to yield 5-aryl-3,4-dihydro-1,8-naphthyridin-2(1H)-ones by an efficient synthetic route. PMID:24605148

  4. Synthesis of 3,4-dihydro-1,8-naphthyridin-2(1H)-ones via microwave-activated inverse electron-demand Diels-Alder reactions.

    PubMed

    Fadel, Salah; Hajbi, Youssef; Khouili, Mostafa; Lazar, Said; Suzenet, Franck; Guillaumet, Gérald

    2014-01-01

    Substituted 3,4-dihydro-1,8-naphthyridin-2(1H)-ones have been synthesized with the inverse electron-demand Diels-Alder reaction from 1,2,4-triazines bearing an acylamino group with a terminal alkyne side chain. Alkynes were first subjected to the Sonogashira cross-coupling reaction with aryl halides, the product of which then underwent an intramolecular inverse electron-demand Diels-Alder reaction to yield 5-aryl-3,4-dihydro-1,8-naphthyridin-2(1H)-ones by an efficient synthetic route. PMID:24605148

  5. The CIELO Collaboration:Neutron Reactions on 1H, 16O, 56Fe, 235,238U, and 239Pu

    SciTech Connect

    Giuseppe Palmiotti; M. B. Chadwick

    2014-04-01

    CIELO (Collaborative International Evaluated Library Organization) provides a new working paradigm to facilitate evaluated nuclear reaction data advances. It brings together experts from across the international nuclear reaction data community to identify and document discrepancies among existing evaluated data libraries, measured data, and model calculation interpretations, and aims to make progress in reconciling these discrepancies to create more accurate ENDF-formatted files. The focus will initially be on a small number of the highest-priority isotopes, namely 1H, 16O, 56Fe, 235,238U, and 239Pu. This paper identifies discrepancies between various evaluations of the highest priority isotopes, and was commissioned by the OECD's Nuclear Energy Agency WPEC (Working Party on International Nuclear Data Evaluation Co-operation) during a meeting held in May 2012. The evaluated data for these materials in the existing nuclear data libraries — ENDF/B-VII.1, JEFF-3.1, JENDL-4.0, CENDL-3.1, ROSFOND, IRDFF 1.0 — are reviewed, discrepancies are identified, and some integral properties are given. The paper summarizes a program of nuclear science and computational work needed to create the new CIELO nuclear data evaluations.

  6. In situ X-ray Diffraction Study of Thin Film Ir/Si Solid State Reactions

    SciTech Connect

    Knaepen, W.; Demeulemeester, J; Deduytsche, D; Jordan-Sweet, J; Vantomme, A; Van Meirhaeghe, R; Detavernier, C; Lavoie, C

    2010-01-01

    The solid state reaction between a thin (30 nm) Ir film and different Si substrates (p-type Si(1 0 0), n- and p-type Si(1 1 1), silicon on insulator (SOI) and polycrystalline Si) was studied using a combination of in situ X-ray diffraction (XRD), in situ sheet resistance and laser light scattering measurements. No significant influence of either the dopants or the substrate orientation was detected as a phase formation sequence of IrSi, Ir{sub 3}Si{sub 4},Ir{sub 3}Si{sub 5} and IrSi{sub 3} was found for all samples. The presence of a thin (<4 nm) amorphous IrSi film at room temperature and its subsequent crystallization could be deduced from the appearance of a broad semi-amorphous diffraction peak in the XRD spectrum around 400 C. The results were verified using ex situ Rutherford Backscattering Spectroscopy, Scanning Electron Microscopy and 4-point probe measurements on quenched samples. The activation energy of the crystallization process and the silicide growth was determined using a Kissinger analysis on ramp anneals with different ramp rates. In addition, the influence of up to 25 volumetric % (20.5 atomic %) of Ir to the silicide formation in the Ni/Si system was studied on SOI and polycrystalline Si substrates. In the presence of Ir, the temperature range over which the low resistivity NiSi exists, is reduced both through an increase in formation temperature and an earlier consumption by the formation of NiSi{sub 2}. After the heat treatment, a continuous distribution of Ir throughout the NiSi{sub 2} phase was detected using X-ray photoelectron spectroscopy depth profiling. A low sheet resistance of < 20 {Omega}/{open_square} was maintained on both substrates up to 900 C.

  7. Conformational analysis, spectroscopic study (FT-IR, FT-Raman, UV, 1H and 13C NMR), molecular orbital energy and NLO properties of 5-iodosalicylic acid.

    PubMed

    Karaca, Caglar; Atac, Ahmet; Karabacak, Mehmet

    2015-02-01

    In this study, 5-iodosalicylic acid (5-ISA, C7H5IO3) is structurally characterized by FT-IR, FT-Raman, NMR and UV spectroscopies. There are eight conformers, Cn, n=1-8 for this molecule therefore the molecular geometry for these eight conformers in the ground state are calculated by using the ab-initio density functional theory (DFT) B3LYP method approach with the aug-cc-pVDZ-PP basis set for iodine and the aug-cc-pVDZ basis set for the other elements. The computational results identified that the most stable conformer of 5-ISA is the C1 form. The vibrational spectra are calculated DFT method invoking the same basis sets and fundamental vibrations are assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method with PQS program. Total density of state (TDOS) and partial density of state (PDOS) and also overlap population density of state (COOP or OPDOS) diagrams analysis for C1 conformer were calculated using the same method. The energy and oscillator strength are calculated by time-dependent density functional theory (TD-DFT) results complement with the experimental findings. Besides, charge transfer occurring in the molecule between HOMO and LUMO energies, frontier energy gap, molecular electrostatic potential (MEP) are calculated and presented. The NMR chemical shifts ((1)H and (13)C) spectra are recorded and calculated using the gauge independent atomic orbital (GIAO) method. Mulliken atomic charges of the title molecule are also calculated, interpreted and compared with salicylic acid. The optimized bond lengths, bond angles and calculated NMR and UV, vibrational wavenumbers showed the best agreement with the experimental results. PMID:25448933

  8. Study of 194Ir via thermal neutron capture and (d,p) reactions .

    NASA Astrophysics Data System (ADS)

    Balodis, M.; Prokofjevs, P.; Kramere, N.; Simonova, L.; Berzins, J.; Krasta, T.; Georgii, R.; von Egidy, T.; Klora, J.; Lindner, H.; Mayerhofer, U.; Walter, A.; Cizewski, J. A.; Colvin, G. G.; Boerner, H. G.; Geltenbort, P.; Hoyler, F.; Kerr, S. A.; Schreckenbach, K.; Raemy, A.; Dousse, J. C.; Kern, J.; Schwitz, W.; Kondurov, I. A.; Loginov, Yu. E.; Sushkov, P. A.; Brant, S.; Paar, V.; Lopac, V.

    Levels of 194Ir were studied using thermal neutron capture reaction. A pair spectrometer was used to measure the high-energy g-ray spectrum from thermal-neutron capture in enriched 193Ir target over the energy range 4640 - 6100 keV. The low-energy g-radiation from the reaction was studied with crystal diffraction spectrometers, and conversion electrons were observed with magnetic spectrometers. The high-sensitivity measurements at the Grenoble reactor, evaluated for transition energies up to 500 keV, are compared with lower-sensitivity measurements at the Wuerenlingen and Salaspils reactors. The comparison helped to obtain reliable isotopic identification for a number of 194Ir lines. The multipolarity admixtures for 29 g-transitions were determined on the basis of conversion lines from different electron subshells. Prompt and delayed g-g coincidences were measured using semiconductor and scintillation detectors. The 193Ir(d,p) high-resolution spectra, observed with a magnetic spectrometer, are given. All these data contributed to establishing a detailed level scheme of 194Ir. Additional data and the interpretation of the results in terms of current models will be presented in a forthcoming paper.

  9. Structural and Electrocatalytic Properties of PtIrCo/C Catalysts for Oxygen Reduction Reaction

    SciTech Connect

    Loukrakpam, Rameshwori; Wanjala, Bridgid N.; Yin, Jun; Fang, Bin; Luo, Jin; Shao, Minhua; Protsailo, Lesia; Kawamura, Tetsuo; Chen, Yongsheng; Petkov, Valeri; Zhong, Chuan-Jian (CMU); (SUNY-Binghamton); (UTC Power); (Toyota); (Penn)

    2011-08-29

    This paper describes the results of an investigation of the synthesis of PtIrCo nanoparticles (2-3 nm) for electrocatalytic oxygen reduction reaction. The carbon-supported PtIrCo catalysts (PtIrCo/C) were thermally treated at temperatures ranging from 400 to 900 C. The size, composition, and atomic-scale structures of the PtIrCo/C catalysts were characterized for establishing their correlation with the electrocatalytic activity toward oxygen reduction reaction. The specific activity was found to increase by a factor of 3-5 for the PtIrCo/C catalysts in comparison with Pt/C catalysts. A correlation was identified between the specific activity and the nanoparticle's fcc-type lattice parameter. The specific activity increases whereas the fcc-type lattice parameter decreases with the thermal treatment temperature. This correlation was further substantiated by analyzing the interatomic spatial parameters in the trimetallic nanoparticles based on X-ray absorption fine structure spectroscopic and high-energy XRD experiments. Implications of these findings, along with the durability of the catalysts, to the design of active electrocatalysts were also discussed.

  10. A regioselective three-component reaction for synthesis of novel 1? H-spiro[isoindoline-1,2?-quinazoline]-3,4?(3? H)-dione derivatives

    Microsoft Academic Search

    Ali A. Mohammadi; M. Dabiri; H. Qaraat

    2009-01-01

    A ring opening and regioselective three-component reaction of isatoic anhydride, isatins, and aromatic or aliphatic primary amines in the presence of catalytic amount of KAl(SO4)2·12H2O (alum) to yield a novel series of 1?H-spiro[isoindoline-1,2?-quinazoline]-3,4?(3?H)-dione is described.

  11. Unexpected Synthesis of 5,6-Dihydropyridin-2(1H)-ones by a Domino Ugi/Aldol/Hydrolysis Reaction Starting from Baylis-Hillman Phosphonium Salts.

    PubMed

    Zeng, Xiao-Hua; Wang, Hong-Mei; Ding, Ming-Wu

    2015-05-01

    A one-pot synthetic approach to 5,6-dihydropyridin-2(1H)-ones has been developed using a domino process involving Ugi, aldol, and hydrolysis reactions, starting with Baylis-Hillman phosphonium salts, primary amines, isocyanides, and arylglyoxals. PMID:25875533

  12. Ohmic Heating-Assisted Synthesis of 3-Arylquinolin-4(1H)-ones by a Reusable and Ligand-Free Suzuki-Miyaura Reaction in Water.

    PubMed

    Pinto, Joana; Silva, Vera L M; Silva, Ana M G; Santos, Luís M N B F; Silva, Artur M S

    2015-07-01

    Potential bioactive 3-arylquinolin-4(1H)-ones were synthesized under ohmic heating using an efficient, reusable, and ligand-free protocol developed for the Suzuki-Miyaura coupling of 1-substituted-3-iodoquinolin-4(1H)-ones with several boronic acids in water using Pd(OAc)2 as a catalyst and tetrabutylammonium bromide (TBAB) as the phase transfer catalyst. Good substrate generality, ease of execution, short reaction time, and practicability make this method exploitable for the generation of libraries of B ring-substituted 3-arylquinolin-4(1H)-ones. After a simple workup, the Pd/catalyst-H2O-TBAB system could be reused for at least seven cycles without significant loss of activity. PMID:26035736

  13. Experimental (FT-IR, FT-Raman and UV-Vis spectra) and density functional theory calculations of diethyl 1H-pyrazole-3,5-dicarboxylate

    NASA Astrophysics Data System (ADS)

    Udaya Sri, N.; Chaitanya, Kadali; Prasad, M. V. S.; Veeraiah, V.; Veeraiah, A.

    2012-07-01

    The vibrational and electronic spectra of diethyl 1H-pyrazole-3,5-dicarboxylate (DE1H35DC) are reported and discussed. In this work the structural properties and vibrational frequencies of diethyl 1H-pyrazole-3,5-dicarboxylate have been investigated extensively using density functional theory (DFT) employing B3LYP exchange correlation with the normal basis level 6-31G(d,p). The first hyperpolarizabilities and electric dipole moments of the said molecule have been computed using quantum mechanical calculations. NBO and HOMO, LUMO analysis has been carried out. The geometries and normal modes of vibrations obtained from B3LYP calculations are in good agreement with the experimentally observed data.

  14. The spectroscopic (FT-IR, FT-Raman, l3C, 1H NMR and UV) and NBO analyses of 4-bromo-1-(ethoxycarbonyl)piperidine-4-carboxylic acid

    NASA Astrophysics Data System (ADS)

    Vitnik, Vesna D.; Vitnik, Željko J.

    2015-03-01

    In this work, we will report a combined experimental and theoretical study on molecular and vibrational structure of 4-bromo-1-(ethoxycarbonyl)piperidine-4-carboxylic acid (BEPA). BEPA has been characterized by FT-IR, FT-Raman, 1H NMR, 13C NMR and UV spectroscopy. The FT-IR and FT-Raman spectra of BEPA were recorded in the solid phase. The optimized geometry was calculated by B3LYP and M06-2X methods using 6-311G(d,p) basis set. The FT-IR and FT-Raman spectra of BEPA were calculated at the same level and were interpreted in terms of Potential Energy Distribution (PED) analysis. The scaled theoretical wavenumber showed very good agreement with the experimental values. The 1H and l3C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by the Gauge-Independent Atomic Orbital (GIAO) method. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using Natural Bond Orbital (NBO) analysis. Density plots over the highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) energy surface directly identifies the donor and acceptor atoms in the molecule. It also provides information about the charge transfer within the molecule. To obtain chemical reactivity of the molecule, the molecular electrostatic potential (MEP) surface map is plotted over the optimized geometry of the molecule.

  15. The spectroscopic (FT-IR, FT-Raman, (l3)C, (1)H NMR and UV) and NBO analyses of 4-bromo-1-(ethoxycarbonyl)piperidine-4-carboxylic acid.

    PubMed

    Vitnik, Vesna D; Vitnik, Željko J

    2015-03-01

    In this work, we will report a combined experimental and theoretical study on molecular and vibrational structure of 4-bromo-1-(ethoxycarbonyl)piperidine-4-carboxylic acid (BEPA). BEPA has been characterized by FT-IR, FT-Raman, (1)H NMR, (13)C NMR and UV spectroscopy. The FT-IR and FT-Raman spectra of BEPA were recorded in the solid phase. The optimized geometry was calculated by B3LYP and M06-2X methods using 6-311G(d,p) basis set. The FT-IR and FT-Raman spectra of BEPA were calculated at the same level and were interpreted in terms of Potential Energy Distribution (PED) analysis. The scaled theoretical wavenumber showed very good agreement with the experimental values. The (1)H and (l3)C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by the Gauge-Independent Atomic Orbital (GIAO) method. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using Natural Bond Orbital (NBO) analysis. Density plots over the highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) energy surface directly identifies the donor and acceptor atoms in the molecule. It also provides information about the charge transfer within the molecule. To obtain chemical reactivity of the molecule, the molecular electrostatic potential (MEP) surface map is plotted over the optimized geometry of the molecule. PMID:25434858

  16. Time-resolved IR observation of a photocatalytic reaction of pivalic acid on platinized titanium dioxide

    NASA Astrophysics Data System (ADS)

    Maeda, Akihiro; Ishibashi, Taka-aki

    2013-06-01

    Photodegradation of pivalic acid [(CH3)3CCOOH] on a Pt/TiO2 photocatalyst was studied by time-resolved IR spectroscopy in the microsecond-to-millisecond time region. A vibrational band due to t-butyl radical species, as a reaction intermediate, was observed at 1456 cm-1 along with decrease of reactant, bridge-adsorbed pivalate, and product formation. The product did not have vibrational bands in the CC double bond stretch region, suggesting that the main product was isobutane instead of isobutene, which was the main product in the photoreaction of pivalate on the rutile TiO2 (1 1 0) single crystal.

  17. Mass of {sup 11}Li from the {sup 1}H({sup 11}Li,{sup 9}Li){sup 3}H reaction

    SciTech Connect

    Roger, T.; Savajols, H.; Mittig, W.; Caamano, M.; Roussel-Chomaz, P. [GANIL, Boulevard Henri Becquerel, Boite Postale 55027, F-14076 Caen Cedex 05 (France); Tanihata, I.; Alcorta, M.; Bandyopadhyay, D.; Bieri, R.; Buchmann, L.; Davids, B.; Galinski, N.; Howell, D.; Mills, W.; Mythili, S.; Openshaw, R.; Padilla-Rodal, E.; Ruprecht, G.; Sheffer, G.; Shotter, A. C. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada)] (and others)

    2009-03-15

    The mass of {sup 11}Li has been determined from Q-value measurements of the {sup 1}H({sup 11}Li,{sup 9}Li){sup 3}H reaction. The experiment was performed at TRIUMF laboratory with the GANIL active target MAYA. Energy-energy and angle-angle kinematics reconstruction give a Q value of 8.119(22) MeV for the reaction. The derived {sup 11}Li two-neutron separation energy is S{sub 2n}=363(22) keV.

  18. Three Component Reaction: An Efficient Synthesis and Reactions of 3,4-Dihydropyrimidin-2(1H)-Ones and Thiones Using New Natural Catalyst

    PubMed Central

    Elmaghraby, A. M.; Mousa, I. A.; Harb, A. A.; Mahgoub, M. Y.

    2013-01-01

    Synthesis of 3,4-dihydropyrimidin-2(1H)-one and 3,4-dihydropyrimidin-2(1H)-thione derivatives from aldehydes, 1,3-dicarbonyl derivatives and urea or thiourea using granite and quartz as new, natural and reusable catalysts. Some of the 3,4-dihydropyrimidin-2(1H)-thione derivatives were used to prepare new heterocyclic compounds. The antimicrobial activity of selected examples of the synthesized compounds was tested and showed moderate activity. PMID:24052868

  19. 2-Carbaborane-3-phenyl-1H-indoles--synthesis via McMurry reaction and cyclooxygenase (COX) inhibition activity.

    PubMed

    Laube, Markus; Neumann, Wilma; Scholz, Matthias; Lönnecke, Peter; Crews, Brenda; Marnett, Lawrence J; Pietzsch, Jens; Kniess, Torsten; Hey-Hawkins, Evamarie

    2013-02-01

    Cyclooxygenase-2 (COX-2) inhibitors have been the focus of medicinal chemistry efforts for years, and many compounds that exhibit high selectivity and affinity have been developed. As carbaboranes represent interesting pharmacophores as phenyl mimetics in drug development, this paper presents the synthesis of carbaboranyl derivatives of COX-2-selective 2,3-disubstituted indoles. Despite the lability of carbaboranes under reducing conditions, 2-carbaborane-3-phenyl-1H-indoles could be synthesized by McMurry cyclization of the corresponding amides. Whereas the meta-carbaboranyl-substituted derivatives lacked COX inhibitory activity, an ortho-carbaboranyl analogue was active, but showed a selectivity shift toward COX-1. PMID:23303738

  20. Assembly of N,N-disubstituted hydrazines and 1-aryl-1H-indazoles via copper-catalyzed coupling reactions.

    PubMed

    Xiong, Xiaodong; Jiang, Yongwen; Ma, Dawei

    2012-05-18

    CuI-catalyzed coupling of N-acyl-N'-substituted hydrazines with aryl iodides takes place at 60-90 °C to afford N-acyl-N',N'-disubstituted hydrazines regioselectively and thereby gives a facile method for assembling N,N-diaryl hydrazines. N-Acyl-N'-substituted hydrazines can also react with 2-bromoarylcarbonylic compounds at 60-125 °C under the catalysis of CuI/4-hydroxy-l-proline to provide 1-aryl-1H-indazoles. PMID:22545771

  1. Analyzing powers for the three-nucleon breakup reaction /sup 1/H(d vector,p)pn at 16 MeV

    SciTech Connect

    Brown, R.E.; Ohlsen, G.G.; Correll, F.D.; Hardekopf, R.A.; Jarmie, N.

    1980-01-01

    Analyzing powers for the /sup 1/H(d,p)pn reaction were measured at 16.0 MeV and beam polarization of approximately 0.82. Similar data for the elastic scattering /sup 1/H(d,p)/sup 2/H were also taken. The breakup analyzing power A/sub xz/, which attains the largest magnitude, is shown as a function of excitation energy. Angular distributions of elastic and breakup analyzing powers are compared; large differences are noted for A/sub xx/ and A/sub xz/. It is found that 1-MeV energy bins are too large to use in the study of singlet-state effects. 2 figures. (RWR)

  2. Activation cross section and isomeric cross-section ratio for the (n,2n) reaction on Ir191

    Microsoft Academic Search

    N. Patronis; C. T. Papadopoulos; S. Galanopoulos; M. Kokkoris; G. Perdikakis; R. Vlastou; A. Lagoyannis; S. Harissopulos

    2007-01-01

    The Ir191(n,2n)Ir190 cross section was measured by means of the activation technique at four neutron energies in the range 10.0 11.3 MeV. The quasimonoenergetic neutron beam was produced via the H2(d,n)He3 reaction at the 5.5 MV Tandem Van de Graaff accelerator of NCSR ``Demokritos.'' The cross section for the population of the second high spin (11-) isomeric state was measured

  3. Activation cross section and isomeric cross-section ratio for the (n,2n) reaction on ¹¹Ir

    Microsoft Academic Search

    N. Patronis; C. T. Papadopoulos; S. Galanopoulos; M. Kokkoris; G. Perdikakis; R. Vlastou; A. Lagoyannis; S. Harissopulos

    2007-01-01

    The ¹¹Ir(n,2n)¹°Ir cross section was measured by means of the activation technique at four neutron energies in the range 10.0-11.3 MeV. The quasimonoenergetic neutron beam was produced via the ²H(d,n)³He reaction at the 5.5 MV Tandem Van de Graaff accelerator of NCSR 'Demokritos'. The cross section for the population of the second high spin (11) isomeric state was measured along

  4. Vibrational (FT-IR and FT-Raman), electronic (UV-Vis), NMR (1H and 13C) spectra and reactivity analyses of 4,5-dimethyl-o-phenylenediamine

    NASA Astrophysics Data System (ADS)

    Atac, Ahmet; Karaca, Caglar; Gunnaz, Salih; Karabacak, Mehmet

    2014-09-01

    The structure of 4,5-dimethyl-o-phenylenediamine (C8H12N2, DMPDA) was investigated on the basis of spectroscopic data and theoretical calculations. The sterochemical structure was determined by FT-IR, FT-Raman, UV, 1H and 13C NMR spectra. An experimental study and a theoretical analysis were associated by using the B3LYP method with Gaussian09 package program. FT-IR and FT-Raman spectra were recorded in the region of 4000-400 cm-1 and 4000-10 cm-1, respectively. The vibrational spectra were calculated by DFT method and the fundamental vibrations were assigned on the basis of the total energy distribution (TED), calculated with scaled quantum mechanics (SQM) method with Parallel Quantum Solutions (PQS) program. The UV absorption spectrum of the compound that dissolved in ethanol solution were recorded in the range of 190-400 nm. Total density of state (TDOS) and partial density of state (PDOS) of the DMPDA in terms of HOMOs and LUMOs were calculated and analyzed. Chemical shifts were reported in ppm relative to tetramethylsilane (TMS) for 1H and 13C NMR spectra. The compound was dissolved in dimethyl sulfoxide (DMSO). Also, 1H and 13C chemical shifts calculated using the gauge independent atomic orbital (GIAO) method. Mullikan atomic charges and other thermo-dynamical parameters were investigated with the help of B3LYP (DFT) method using 6-311++G** basis set. On the basis of the thermodynamic properties of the title compound at different temperatures have been carried out, revealing the correlations between heat capacity (C), entropy (S), enthalpy changes (H) and temperatures. The optimized bond lengths, bond angles, chemical shifts and vibrational wavenumbers showed the best agreement with the experimental results.

  5. Vibrational (FT-IR and FT-Raman), electronic (UV-Vis), NMR (1H and 13C) spectra and reactivity analyses of 4,5-dimethyl-o-phenylenediamine.

    PubMed

    Atac, Ahmet; Karaca, Caglar; Gunnaz, Salih; Karabacak, Mehmet

    2014-09-15

    The structure of 4,5-dimethyl-o-phenylenediamine (C8H12N2, DMPDA) was investigated on the basis of spectroscopic data and theoretical calculations. The sterochemical structure was determined by FT-IR, FT-Raman, UV, 1H and 13C NMR spectra. An experimental study and a theoretical analysis were associated by using the B3LYP method with Gaussian09 package program. FT-IR and FT-Raman spectra were recorded in the region of 4000-400 cm(-1) and 4000-10 cm(-1), respectively. The vibrational spectra were calculated by DFT method and the fundamental vibrations were assigned on the basis of the total energy distribution (TED), calculated with scaled quantum mechanics (SQM) method with Parallel Quantum Solutions (PQS) program. The UV absorption spectrum of the compound that dissolved in ethanol solution were recorded in the range of 190-400 nm. Total density of state (TDOS) and partial density of state (PDOS) of the DMPDA in terms of HOMOs and LUMOs were calculated and analyzed. Chemical shifts were reported in ppm relative to tetramethylsilane (TMS) for 1H and 13C NMR spectra. The compound was dissolved in dimethyl sulfoxide (DMSO). Also, 1H and 13C chemical shifts calculated using the gauge independent atomic orbital (GIAO) method. Mullikan atomic charges and other thermo-dynamical parameters were investigated with the help of B3LYP (DFT) method using 6-311++G** basis set. On the basis of the thermodynamic properties of the title compound at different temperatures have been carried out, revealing the correlations between heat capacity (C), entropy (S), enthalpy changes (H) and temperatures. The optimized bond lengths, bond angles, chemical shifts and vibrational wavenumbers showed the best agreement with the experimental results. PMID:24813280

  6. Quantum mechanical and spectroscopic (FT-IR, FT-Raman, 1H NMR and UV) investigations of 2-(phenoxymethyl)benzimidazole

    NASA Astrophysics Data System (ADS)

    Mary, Y. Shyma; Jojo, P. J.; Panicker, C. Yohannan; Van Alsenoy, Christian; Ataei, Sanaz; Yildiz, Ilkay

    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 2-(phenoxymethyl)benzimidazole have been investigated experimentally and theoretically using Gaussian09 software package. The energy and oscillator strength calculated by time dependent density functional theory results almost compliments with experimental findings. Gauge-including atomic orbital 1H NMR chemical shifts calculations were carried out and compared with experimental data. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. Molecular Electrostatic Potential was performed by the DFT method and the infrared intensities and Raman activities have also been reported. Mulliken’s net charges have been calculated and compared with the atomic natural charges. First hyperpolarizability is calculated in order to find its role in non-linear optics.

  7. FTIR and 1H NMR studies of proton transfer reactions from `C-acids' to N-bases in acetonitrile

    NASA Astrophysics Data System (ADS)

    Brzezinski, Bogumil; Schroeder, Grzegorz; Olejnik, Jerzy; Jarczewski, Arnold; Grech, Eugeniusz; Milart, Piotr

    1997-04-01

    Deprotonation of `C-acids': benzoylmalononitrile ( 1), and 4-nitrophenylmalononitrile ( 2), triethoxycarbonylmethane ( 3), diethyl cyanomalonate ( 4) and ethyl 1,3-indandione-2-carboxylate ( 5), by 7-methyl-1,5,7-triaza-bicyclo[4.4.O]dec-5-ene (MTBD) and 1,8-bis(dimethylamino)naphthalene (DMAN) in acetonitrile was studied by FTIR and 1H NMR methods. The results demonstrate that the proton transfer mechanism from `C-acids' to N-bases in acetonitrile is determined by different distributions of charge in the carbanion and the protonated N-base as well as by the structures of the C-acid and N-base molecules.

  8. 2-Carbaborane-3-phenyl-1H-indoles – Synthesis via McMurry Reaction and COX Inhibition Activity

    PubMed Central

    Neumann, Wilma; Scholz, Matthias; Lönnecke, Peter; Crews, Brenda; Marnett, Lawrence J.; Pietzsch, Jens; Kniess, Torsten

    2013-01-01

    Cyclooxygenase-2 (COX-2) inhibitors have been in the focus of medicinal chemistry for years and many compounds exhibiting high selectivity and affinity were developed. As carbaboranes represent interesting pharmacophores as phenyl mimetics in drug development, this paper presents the synthesis of carbaboranyl derivatives of COX-2-selective 2,3-disubstituted indoles. Despite the lability of carbaboranes under reducing conditions, 2-carbaborane-3-phenyl-1H-indoles could be synthesized by McMurry cyclization of the corresponding amides. While the meta-carbaboranyl-substituted derivatives (3a-c) lacked COX inhibition activity, the ortho-carbaboranyl analog (3d) was active but showed a selectivity shift towards COX-1. PMID:23303738

  9. New Convenient Strategy for Annulation of Pyrimidines to Thiophenes or Furans via the One-pot Multistep Cascade Reaction of 1H-Tetrazoles with Aliphatic Amines.

    PubMed

    Pokhodylo, Nazariy T; Shyyka, Olga Ya; Matiychuk, Vasyl S; Obushak, Mykola D

    2015-07-13

    A versatile, convenient, efficient and high-yield synthetic method for 2-R(3),R(4)-amino-5-R(1)-6-R(2)-thieno[2,3-d]pyrimidin-4(3H)-ones, 2-R(3),R(4)-amino-5-R(1)-6-R(2)-thieno[3,2-d]pyrimidin-4(3H)-ones, and benzofuro[3,2-d]pyrimidin-4(3H)-ones preparation has been developed. The reaction proceeded without using solvents and included several steps. A variety of thieno[2,3-d]pyrimidine and thieno[3,2-d]pyrimidine derivatives with substituents of different nature were obtained in high yields from substituted alkyl 2-(1H-tetrazol-1-yl)thiophene-3-carboxylates, 3-(1H-tetrazol-1-yl)thiophene-2-carboxylates, and 3-(1H-tetrazol-1-yl)benzofuran-2-carboxylate after their treatment with aliphatic amines. PMID:26091557

  10. Experimental study and nuclear model calculations on the 192Os(p,n)192Ir reaction: Comparison of reactor and cyclotron production of the therapeutic radionuclide 192Ir.

    PubMed

    Hilgers, K; Sudár, S; Qaim, S M

    2005-07-01

    In a search for an alternative route of production of the important therapeutic radionuclide (192)Ir (T(1/2)=78.83 d), the excitation function of the reaction (192)Os(p,n)(192)Ir was investigated from its threshold up to 20 MeV. Thin samples of enriched (192)Os were obtained by electrodeposition on Ni, and the conventional stacked-foil technique was used for cross section measurements. The experimental data were compared with the results of theoretical calculations using the codes EMPIRE-II and ALICE-IPPE. Good agreement was found with EMPIRE-II, but slightly less with the ALICE-IPPE calculations. The theoretical thick target yield of (192)Ir over the energy range E(p)=16-->8 MeV amounts to only 0.16MBq/muA.h. A comparison of the reactor and cyclotron production methods is given. In terms of yield and radionuclidic purity of (192)Ir the reactor method appears to be superior; the only advantage of the cyclotron method could be the higher specific activity of the product. PMID:15866453

  11. Molecular structure, spectroscopic (FT-IR, FT-Raman, 13C and 1H NMR, UV), polarizability and first-order hyperpolarizability, HOMO and LUMO analysis of 4'-methylbiphenyl-2-carbonitrile.

    PubMed

    Karabacak, Mehmet; Yilan, Erkan

    2012-02-15

    In the present study, the molecular structure, vibrational and electronic transition, isotropic chemical shifts analysis of 4'-methylbiphenyl-2-carbonitrile were presented using experimental techniques (FT-IR, FT-Raman, NMR and UV) and quantum chemical calculations. FT-IR and FT-Raman spectra in solid state were observed in the region 4000-400cm(-1) and 3500-50cm(-1), respectively. The ultraviolet absorption spectrum of studied compound that dissolved in ethanol was examined in the range of 200-400nm. The (1)H and (13)C NMR spectra were recorded in DMSO solution. To determine lowest-energy molecular conformation of the title molecule, the selected torsion angle is varied every 10° and molecular energy profile is calculated from 0° to 360°. The molecular structure and spectroscopic data of the molecule in the ground state were computed by density functional theory (DFT) using 6-31++G(d,p) basis set. The complete assignments of all vibrational modes were performed on the basis of the total energy distributions (TED) of the vibrational modes, computed with scaled quantum mechanics (SQM) method. (13)C and (1)H isotropic chemical shifts were computed using the gauge-invariant atomic orbital (GIAO) method. Moreover, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies, absorption wavelength were performed by time-dependent DFT approach. The dipole moment, linear polarizability and first hyperpolarizability values were also computed. The linear polarizabilities and first hyper polarizabilities of the studied molecule indicate that the compound is a good candidate of nonlinear optical materials. Comparison of the calculated frequencies, NMR chemical shifts, absorption wavelengths with the experimental values revealed that DFT method produces good results. PMID:22185952

  12. Spectroscopic investigation (FT-IR and FT-Raman), vibrational assignments, HOMO-LUMO, NBO, MEP analysis and molecular docking study of 2-(4-hydroxyphenyl)-4,5-dimethyl-1H-imidazole 3-oxide

    NASA Astrophysics Data System (ADS)

    Benzon, K. B.; Varghese, Hema Tresa; Panicker, C. Yohannan; Pradhan, Kiran; Tiwary, Bipransh Kumar; Nanda, Ashis Kumar; Alsenoy, C. Van

    2015-07-01

    In this work, the vibrational spectral analysis was carried out using FT-IR and FT-Raman spectroscopy of 2-(4-hydroxyphenyl)-4,5-dimethyl-1H-imidazole 3-oxide. The computations were performed at DFT levels of theory to get the optimized geometry and vibrational frequencies of the normal modes of the title compound using Gaussian09 software. The complete vibrational assignments of frequencies were made on the basis of potential energy distribution. The calculated HOMO and LUMO energies show the chemical activity of the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The hyperpolarizability values are reported and the first hyperpolarizability of the title compound is 19.61 times that of standard NLO material urea. From the MEP plot, the negative charge covers the nitro group and the positive region is over the hydroxyl group and N-H part of the imidazole ring. The calculated 1H NMR results are in good agreement with experimental data. Molecular docking study is also reported.

  13. Spectroscopic investigation (FT-IR and FT-Raman), vibrational assignments, HOMO-LUMO, NBO, MEP analysis and molecular docking study of 2-(4-hydroxyphenyl)-4,5-dimethyl-1H-imidazole 3-oxide.

    PubMed

    Benzon, K B; Varghese, Hema Tresa; Panicker, C Yohannan; Pradhan, Kiran; Tiwary, Bipransh Kumar; Nanda, Ashis Kumar; Van Alsenoy, C

    2015-07-01

    In this work, the vibrational spectral analysis was carried out using FT-IR and FT-Raman spectroscopy of 2-(4-hydroxyphenyl)-4,5-dimethyl-1H-imidazole 3-oxide. The computations were performed at DFT levels of theory to get the optimized geometry and vibrational frequencies of the normal modes of the title compound using Gaussian09 software. The complete vibrational assignments of frequencies were made on the basis of potential energy distribution. The calculated HOMO and LUMO energies show the chemical activity of the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The hyperpolarizability values are reported and the first hyperpolarizability of the title compound is 19.61 times that of standard NLO material urea. From the MEP plot, the negative charge covers the nitro group and the positive region is over the hydroxyl group and N-H part of the imidazole ring. The calculated (1)H NMR results are in good agreement with experimental data. Molecular docking study is also reported. PMID:25819320

  14. Quantum mechanical calculations and spectroscopic (FT-IR, FT-Raman and UV) investigations, molecular orbital, NLO, NBO, NLMO and MESP analysis of 4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl] benzene-1-sulfonamide

    NASA Astrophysics Data System (ADS)

    Govindasamy, P.; Gunasekaran, S.

    2015-02-01

    The molecular structural parameters and vibrational frequencies of the fundamental modes of 4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl] benzene-1-sulfonamide(abbreviated as 4MPTFM1HPB1SA) have been obtained using Density functional theory (DFT) technique in the B3LYP approximation with 6-311G(d,p) and 6-311++G(d,p) basis sets. Detailed vibrational assignments of the observed FT-IR and FT-Raman bands have been proposed on the basis of potential energy distribution (PED). The difference between the observed and the calculated wavenumbers values are very small. The theoretically predicted FT-IR and FT-Raman spectra of the title molecule have been constructed. The molecular electrostatic potential has been mapped primarily for predicting sites and relative reactivities toward electrophilic and nucleophilic attack. The intramolecular contacts have been interpreted using Natural Bond Orbital (NBO) and Natural Localized Molecular Orbital (NLMO) analysis. Important non-linear properties such as electric dipolemoment and first hyperpolarizability of 4MPTFM1HPB1SA have been computed using B3LYP quantum chemical calculation. The absorption wavelength, energy and oscillator's strength are calculated by TD-DFT and 4MPTFM1HPB1SA is approach complement with the experimental findings. The temperature dependence of thermodynamic properties has been analyzed. The Natural charges, Frontier molecular orbitals (FMOs), chemical hardness (?), chemical potential (?), Electro negativity (?) and electrophilicity values (?) are calculated and reported.

  15. Monomeric and dimeric structures analysis and spectroscopic characterization of 3,5-difluorophenylboronic acid with experimental (FT-IR, FT-Raman, 1H and 13C NMR, UV) techniques and quantum chemical calculations

    NASA Astrophysics Data System (ADS)

    Karabacak, Mehmet; Kose, Etem; Atac, Ahmet; Asiri, Abdullah M.; Kurt, Mustafa

    2014-01-01

    The spectroscopic properties of 3,5-difluorophenylboronic acid (3,5-DFPBA, C6H3F2B(OH)2) were investigated by FT-IR, FT-Raman UV-Vis, 1H and 13C NMR spectroscopic techniques. FT-IR (4000-400 cm-1) and FT-Raman spectra (3500-10 cm-1) in the solid phase and 1H and 13C NMR spectra in DMSO solution were recorded. The UV spectra that dissolved in ethanol and water were recorded in the range of 200-400 nm for each solution. The structural and spectroscopic data of the molecule have been obtained for possible three conformers from DFT (B3LYP) with 6-311++G(d,p) basis set calculations. The geometry of the molecule was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. Hydrogen-bonded dimer of title molecule, optimized by counterpoise correction, was also studied B3LYP at the 6-311++G(d,p) level and the effects of molecular association through O-H⋯O hydrogen bonding have been discussed. 1H and 13C NMR chemical shifts were calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, oscillator strength, wavelengths, HOMO and LUMO energies, were performed by time-dependent density functional theory (TD-DFT) results complements with the experimental findings. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (OPDOS) diagrams analysis were presented. The effects due to the substitutions of boric acid group and halogen were investigated. The results of the calculations were applied to simulate spectra of the title compound, which show excellent agreement with observed spectra. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP), nonlinear optical properties (NLO) and thermodynamic features were performed.

  16. Kinetic study of the reaction CH (X 2Pi) + H2 yields CH2 (X 3B1) + H in the temperature range 372 to 675 K

    NASA Technical Reports Server (NTRS)

    Zabarnick, S.; Fleming, J. W.; Lin, M. C.

    1986-01-01

    The kinetics of the reversible reaction CH (X 2Pi) + H2 yields CH2 (X 3B1) + H at 372-675 K and total pressure 100 torr (mainly Ar) is investigated experimentally. The ground-state CH radicals are produced by photolysis of CHBr3 using 10-mJ 266-nm laser pulses (repetition rate 10 Hz) and monitored by measuring the fluorescence induced by a 429.8-nm dye laser, in the apparatus described by Berman et al. (1982) and Berman and Lin (1984). The results are presented in tables and graphs and characterized. The absolute rate constants for the forward and reverse reactions are determined, and their temperature dependence is given by Arrhenius expressions and formulas obtained in transition-state-theory calculations. The heat of formation of CH2 at 0 K is estimated (assuming that the recombination reaction CH2 + H has zero activation energy) as 92.6 + or - 0.5 kcal/mol.

  17. Measurements of the Electric Form Factor of the Neutron from the ^2H( e,e' n)^1H Reaction at Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Madey, Richard

    2001-10-01

    The JLab E93-038 collaboration measured the electric form factor of the neutron, G^n_E, via quasi-elastic scattering from the ^2H( e,e' n)^1H reaction at three values of the squared four-momentum transfer Q^2 [viz., 0.45, 1.15, and 1.47 (GeV/c)^2]. By measuring the ratio of two scattering asymmetries associated with two different precession angles of the neutron polarization vector, systematic uncertainties are minimal because the polarimeter analyzing power and the beam polarization do not enter in the ratio. Preliminary results for G^nE will be discussed. Projected uncertainties are ~ 0.005 for the lowest Q^2 and ~ 0.004 for the other two Q^2 points.

  18. Longitudinal and Transverse Cross Sections in the {sup 1}H ({ital e},thinspthinsp {ital e}{sup {prime}}{ital K}{sup +}){Lambda} Reaction

    SciTech Connect

    Niculescu, G.; Gueye, P.; Ahmidouch, A.; Assamagan, K.; Avery, S.; Baker, O.K.; Beard, K.; Cha, J.; Eden, T.; Harvey, M.; Hinton, W.; Keppel, C.; Madey, R.; Niculescu, I.; Savage, G.; Tang, L.; Williams, R. [Hampton University, Hampton, Virginia 23668 (United States)] [Hampton University, Hampton, Virginia 23668 (United States); Mohring, R.M.; Beise, E.; Breuer, H.; Chang, C.C.; Chant, N.; Collins, G.; Duncan, F.; Ewell, L.; Gustafsson, K.K.; Lung, A.; Roos, P. [University of Maryland, College Park, Maryland 20742 (United States)] [University of Maryland, College Park, Maryland 20742 (United States); Abbott, D.; Baker, O.K.; Carlini, R.; Dunne, J.; Ent, R.; Keppel, C.; Mack, D.; Majewski, S.; Mitchell, J.; Tang, L.; Vulcan, W.; Wood, S.; Yan, C. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)] [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Ahmidouch, A.; Madey, R. [Kent State University, Kent, Ohio 44242 (United States)] [Kent State University, Kent, Ohio 44242 (United States); Amatuni, T.A.; Mkrtchyan, H.; Stepanyan, S.; Tadevosian, V. [Yerevan Physics Institute, Yerevan, (Armenia) 375306] [Yerevan Physics Institute, Yerevan, (Armenia) 375306; Ambrozewicz, P.; Martoff, C.J. [Temple University, Philadelphia, Pennsylvania 19122 (United States)] [Temple University, Philadelphia, Pennsylvania 19122 (United States); Angelescu, T.; Mihul, A.; Teodorescu, L. [Bucharest University, Bucharest, (Romania) R76900] [Bucharest University, Bucharest, (Romania) R76900; Armstrong, C.S.; Finn, M.; Meekins, D. [College of William and Mary, Williamsburg, Virginia 23187 (United States)] [College of William and Mary, Williamsburg, Virginia 23187 (United States); Bailey, K.; Cummings, W.; Geesaman, D.F.; Hansen, J.; Potterveld, D.; Reinhold, J.; Zeidman, B. [Argonne National Laboratory, Argonne, Illinois 60439 (United States)] [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Beedoe, S.; Danagoulian, S.; Jackson, C.; Mtingwa, S.; Sawafta, R. [North Carolina A T State University, Greensboro, North Carolina 27411 (United States)] [North Carolina A T State University, Greensboro, North Carolina 27411 (United States); Volmer, J. [Free University, Amsterdam, (The Netherlands) 1081] [Free University, Amsterdam, (The Netherlands) 1081; Cisbani, E.; De Leo, R.; Frullani, S.; Garibaldi, F.; Iodice, M.; Leone, T.; Lolos, G.; Perrino, R.; Urciuoli, G.M. [Physics Laboratory, Istituto Superiore di Sanita and INFN-Sezione Sanita, Rome, (Italy) I-00161] [Physics Laboratory, Istituto Superiore di Sanita and INFN-Sezione Sanita, Rome, (Italy) I-00161; Dutta, D.; Segel, R. [Northwestern University, Evanston, Illinois 60201 (United States)] [Northwestern University, Evanston, Illinois 60201 (United States); Eyraud, L.; Furget, C.; Kox, S.; Real, J. [ISN, Grenoble, (France)] [ISN, Grenoble, (France)

    1998-08-01

    The {sup 1}H( e,thinspe{sup {prime}}K{sup +}){Lambda} reaction was studied as a function of the squared four-momentum transfer, Q{sup 2} , and the virtual photon polarization, {var_epsilon} . For each of four Q{sup 2} settings, 0.52, 0.75, 1.00, and 2.00 (GeV/c){sup 2} , the longitudinal and transverse virtual photon cross sections were extracted in measurements at three virtual photon polarizations. The Q{sup 2} dependence of the {sigma}{sub L}/{sigma}{sub T} ratio differs significantly from current theoretical predictions. This, combined with the precision of the measurement, implies a need for revision of existing calculations. {copyright} {ital 1998} {ital The American Physical Society }

  19. FT-IR Study On The Kinetics Of The Reaction Of 4,4'-Diisocyanatediphenylmethane With 1,4-Butanediol

    NASA Astrophysics Data System (ADS)

    Xu, Zhen-Hua; Huang, Zu X.; Xu, Hong J.

    1989-12-01

    The polyurethanes which have emerged as important industrial and biomedical engineering materials were synthesised by reaction of isocyanates with alcohols. Their reaction kinetics in the apolar solvents have been widely studied[1-3]. In the polar solvents which are really used in the practice synthesis, their reaction velocities are much higher than in the apolar solvents. Since the FT-IR spectroscopy has rapid and sensitive advantages, It has been applied to study the reaction of isocyanates in the formation of plastic foams [4], here we tried to study the reaction kinetics of 4,4'-diisocyanatediphenylmethane ( MDI ) with 1,4-butanediol (1,4-BD) in N,N-dimethylformamide(DMF) or dimethyl sulfoxide (DMS0) solvents utilizing this technique.

  20. Impact of IrRu Oxygen Evolution Reaction Catalysts on Pt Nanostructured Thin Films under Start-Up/Shutdown Cycling

    SciTech Connect

    Cullen, David A [ORNL; More, Karren Leslie [ORNL; Atanasoska, Liliana [3M, Industrial Mineral Products Division; Atanasoski, Radoslav [3M, Industrial Mineral Products Division

    2014-01-01

    Electron microscopy and X-ray photoelectron spectroscopy (XPS) methods have been utilized to study the role of oxygen evolution reaction (OER) catalysts in mitigating degradation arising from start-up/shutdown events. Pt nanostructured thin films (NSTF) were coated with a Ru0.1Ir0.9 OER catalyst at loadings ranging from 1 to 10 g/cm2 and submitted to 5,000 potential cycles within a membrane electrode assembly. Analysis of the as-deposited catalyst showed that Ir and Ru coating is primarily metallic, and further evidence is provided to support the previously reported interaction between Ru and the perylene-red support. Aberration-corrected scanning transmission electron microscopy and energy dispersive X-ray spectroscopy were used to observe the impact of the OER catalysts on Pt dissolution and migration through the membrane. Elemental mapping showed a high percentage of the Ir catalyst was maintained on the NSTF whisker surfaces following testing. The presence of the OER catalysts greatly reduced the smoothing of the Pt NSTF whiskers, which has been correlated with Pt dissolution and losses in electrochemically active surface area. The dissolution of both Ir and Pt led to the formation of IrPt nanoparticle clusters in the membrane close to the cathode, as well as the formation of a Pt band deeper in the membrane.

  1. Reaction Kinetics and Intermediate Determination of Solid Acid Catalysed Liquid-phase Hydrolysis Reactions: A Real-time in situ ATR FT-IR Study

    Microsoft Academic Search

    Gerben M. Hamminga; Guido Mul; Jacob A. Moulijn

    2006-01-01

    The appearance of catalyst–reactant interactions observed in on-line ATR FT-IR spectra of Nafion\\/silica catalysed esterification\\u000a and etherification reactions of 1-octanol was investigated. It was assessed by variation of catalyst and solvent that the\\u000a catalyst–reactant band is a result of the reaction of silica with 1-octanol, yields Si–O–R functionalities. Based on off-line\\u000a TPD-MS and TGA characterisation of the used solid catalyst

  2. Spectroscopic (IR, Raman, UV, 1H and 13C NMR) and microbiological studies of Fe(III), Ni(II), Cu(II), Zn(II) and Ag(I) picolinates

    NASA Astrophysics Data System (ADS)

    Kalinowska, M.; Borawska, M.; ?wis?ocka, R.; Piekut, J.; Lewandowski, W.

    2007-05-01

    The FT-IR, Raman spectra of picolinic acid as well as Fe(III), Zn(II), Cu(II), Ni(II) and Ag(I) picolinates were registered, assigned and compared. Some regularities in the spectra of studied picolinates within the regions: 1650-1340 cm -1 [ ?(CC) ar, ?as(COO -), ?s(COO -)]; 1300-1020 cm -1 [ ?(CH)]; 780-620 cm -1 [ ?(CH), ?(CCC)] were found. 1H and 13C NMR spectra for picolinic acid, Zn(II) and Ag(I) picolinates were recorded and studied as well. Moreover the UV spectra of picolinic and picolinates were registered and compared. The influence of Ag(I), Zn(II), Ni(II), Cu(II) and Fe(III) on the electronic system of picolinic acid was investigated. The microbiological activity of picolinates against two species of bacteria: Escherichia coli, Bacillus subtilis as well as two species of yeasts: Saccharomyces cerevisiae and Hansenula anomala was also studied.

  3. Molecular structures, FT-IR and FT-Raman spectra, NBO analysis, NLO properties, reactive sites and quantum chemical calculations of keto-enol tautomerism (2-amino-4-pyrimidinol and 2-amino-pyrimidine-4(1H)-one)

    NASA Astrophysics Data System (ADS)

    Balachandran, V.; Parimala, K.

    2013-02-01

    The keto-enol tautomerism of 2-amino-4-pyrimidinol (APN) and 2-amino-pyrimidine-4(1H)-one (APO) are investigated by vibrational spectroscopy and quantum chemical method. FT-IR and FT-Raman spectra are recorded in the regions of 4000-400 cm-1 and 3500-100 cm-1, respectively for APN. Geometrical parameters, vibrational wavenumbers of APN and APO are predicted by density functional theory (DFT) employing B3LYP level with 6-311++G(d,p) and 6-311++G(2d,p) basis sets. The non-linear optical (NLO) properties of the title molecules are computed. The molecular electrostatic potential (MEP) surface maps are plotted and explained in detail. Natural bond orbital (NBO) analyses have been performed on APN molecule. The significant changes in occupancies and the energies of bonding and antibonding orbital have been explained in detail. Thermodynamic properties (heat capacities, entropies, and enthalpy) and their correlations with temperatures are also obtained from the calculated frequencies of the optimized structures. Reactivity descriptors, Fukui functions and electrophilic sites are found and discussed.

  4. Quantum mechanical study and spectroscopic (FT-IR, FT-Raman, (13)C, (1)H) study, first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis of 2-acetoxybenzoic acid by density functional methods.

    PubMed

    Bhavani, K; Renuga, S; Muthu, S; Sankara Narayanan, K

    2014-10-15

    In this work, colorless crystals of 2-acetoxybenzoic acid were grown by slow evaporation method and the FT-IR and FT-Raman spectra of the sample were recorded in the region 4000-500cm(-1) and 4000-100cm(-1) respectively. Molecular structure is optimized with the help of density functional theory method (B3LYP) with 6-31+G(d,p), 6-311++G(d,p) basis sets. Stability of the molecule arising from hyperconjugation and charge delocalization is confirmed by the natural bond orbital analysis (NBO). The results show that electron density (ED) in the ?(?) antibonding orbitals and E(2) energies confirms the occurrence of intramolecular charge transfer (ICT) within the molecule. The assignments of the vibrational spectra have been carried out with the help of normal coordinate analysis following the scaled quantum mechanical force field (SQMFF) methodology. The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by GIAO method. Mulliken population analysis on atomic charges is also calculated. The calculated HOMO and LUMO energy gap shows that charge transfer occurs within the molecule. PMID:25456668

  5. Quantum mechanical study and spectroscopic (FT-IR, FT-Raman, 13C, 1H) study, first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis of 2-acetoxybenzoic acid by density functional methods

    NASA Astrophysics Data System (ADS)

    Bhavani, K.; Renuga, S.; Muthu, S.; Sankara narayanan, K.

    2015-02-01

    In this work, colorless crystals of 2-acetoxybenzoic acid were grown by slow evaporation method and the FT-IR and FT-Raman spectra of the sample were recorded in the region 4000-500 cm-1 and 4000-100 cm-1 respectively. Molecular structure is optimized with the help of density functional theory method (B3LYP) with 6-31+G(d,p), 6-311++G(d,p) basis sets. Stability of the molecule arising from hyperconjugation and charge delocalization is confirmed by the natural bond orbital analysis (NBO). The results show that electron density (ED) in the ?? antibonding orbitals and E(2) energies confirms the occurrence of intramolecular charge transfer (ICT) within the molecule. The assignments of the vibrational spectra have been carried out with the help of normal coordinate analysis following the scaled quantum mechanical force field (SQMFF) methodology. The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by GIAO method. Mulliken population analysis on atomic charges is also calculated. The calculated HOMO and LUMO energy gap shows that charge transfer occurs within the molecule.

  6. Synthesis of 2,3-Dihydro-1H-2-benzazepin-1-ones and 3H-2-Benzoxepin-1-ones by Isocyanide-Based Multicomponent Reaction/Wittig Sequence Starting from Phosphonium Salt Precursors.

    PubMed

    Wang, Long; Ren, Zhi-Lin; Ding, Ming-Wu

    2015-01-01

    A one-pot synthesis of multisubstituted 2,3-dihydro-1H-2-benzazepin-1-ones and 3H-2-benzoxepin-1-ones by an I-MCR/Wittig sequence was developed. The reaction of phosphonium salt 3, arylglyoxals 4, amine 5 (or without), and isocyanide 6 produced the 2,3-dihydro-1H-2-benzazepin-1-ones 8 or 3H-2-benzoxepin-1-ones 10 in good yields via a sequential Ugi or Passerini condensation and intramolecular Wittig reaction in the presence of NEt3. PMID:25469708

  7. Mechanisms and reaction pathways for simultaneous oxidation of NOx and SO? by ozone determined by in situ IR measurements.

    PubMed

    Sun, Chenglang; Zhao, Nan; Zhuang, Zhuokai; Wang, Haiqiang; Liu, Yue; Weng, Xiaole; Wu, Zhongbiao

    2014-06-15

    Ozone (O3) oxidation combined with wet scrubbing is a promising method for the simultaneous removal of SO2 and NOx in flue gas. In this study, the O3 oxidation processes of NO and SO2, as well as their coexistence, were investigated using an in situ IR spectrometer. Experimental results showed that the O3 concentration and the reaction temperature played critical roles in the O3 oxidation process of NO. Around 80°C, when inlet molar ratio of O3/NO was less than 1, NO was mainly oxidized to NO2, while when the ratio was greater than 1, NO would be further oxidized to NO3, N2O5, and HNO3. NO3 was the key intermediate product for the formation of N2O5 and HNO3. However, the subsequent reactions of NO3 were temperature dependence. With the increase of reaction temperature above 100°C, the concentration of NO2 increased whereas the concentrations of N2O5 and HNO3 decreased. The oxidation of SO2 by O3 was negligible and SO2 had little influence on the oxidation of NO in the simultaneous oxidation of NO and SO2. Finally, based on the in situ IR results, the oxidation mechanism is discussed and the reaction pathways are proposed. PMID:24801895

  8. One-pot three component condensation reaction in water: an efficient and improved procedure for the synthesis of furo[2,3- d]pyrimidine-2,4(1 H,3 H)-diones

    Microsoft Academic Search

    Ahmad Shaabani; Mohammad Bagher Teimouri; Hamid Reza Bijanzadeh

    2002-01-01

    The environment-friendly three component condensation reactions of N,N?-dimethylbarbituric acid, 4-nitrobenzaldehyde and alkyl or aryl isocyanides to afford the corresponding furo[2,3-d]pyrimidine-2,4(1H,3H)-diones, in water, in high yields after several minutes are reported.

  9. Preignition reactions of AP-HTPB propellants studied by IR spectrometry. [Ammonium Perchlorate-Hydroxyl Terminated PolyButadiene

    NASA Technical Reports Server (NTRS)

    Law, R. J.; Baer, A. D.; Ryan, N. W.

    1977-01-01

    IR absorption spectrometry was used to follow the disappearance of NH and CH bonds during the pyrolysis of a polymer film containing 30 weight percent ammonium perchlorate (AP). The remaining 70 weight percent consisted of a mixture of 92.5 weight percent hydroxyl-terminated polybutadiene (HTPB) and 7.5 weight percent isophrone diisocyanate (IPDI). The results indicate that polymer decomposition is induced by products of AP decomposition, and that about 2.5 CH bonds disappear for each NH bond that disappears. The diffusion process occurring in the later stages of the reaction is analyzed in an attempt to account for the unexpectedly low activation energy.

  10. Simultaneous IR and time-resolved X-ray diffraction measurements for studying self-sustained reactions.

    PubMed

    Bernard, F; Gaffet, E; Gramond, M; Gailhanou, M; Gachon, J C

    2000-01-01

    Self-propagating high-temperature synthesis provides an attractive practical method for producing advanced materials such as ceramics, composites and intermetallics. This kind of reaction has been investigated in situ using time-resolved X-ray diffraction, with an X-ray synchrotron beam (D43 beamline, LURE, Orsay) coupled to simultaneous IR thermography to study structural transformations and thermal evolution. With short acquisition times (30 ms per pattern) it has been possible to observe several steps before obtaining compounds. Two different compound formations have been described: (i) the different steps of reaction, aluminium melting, subsequent temperature increase and fast reaction between Al and Ni at such temperatures that only Ni and AlNi are solid and all other compositions are liquid and well identified; (ii) the formation of FeAl. Here, a portion of the iron seems to transform into its allotropic phase and this transition stabilizes the reaction temperature at approximately 1173 K. In addition, the aluminium melting during the reaction explains why the nanostructure induced by the mechanical activation is maintained in the end product. PMID:16609169

  11. Adsorption and oxidation of formaldehyde on a polycrystalline Pt film electrode: An in situ IR spectroscopy search for adsorbed reaction intermediates

    PubMed Central

    Behm, R Jürgen

    2014-01-01

    Summary As part of a mechanistic study of the electrooxidation of C1 molecules we have systematically investigated the dissociative adsorption/oxidation of formaldehyde on a polycrystalline Pt film electrode under experimental conditions optimizing the chance for detecting weakly adsorbed reaction intermediates. Employing in situ IR spectroscopy in an attenuated total reflection configuration (ATR-FTIRS) with p-polarized IR radiation to further improve the signal-to-noise ratio, and using low reaction temperatures (3 °C) and deuterium substitution to slow down the reaction kinetics and to stabilize weakly adsorbed reaction intermediates, we could detect an IR absorption band at 1660 cm?1 characteristic for adsorbed formyl intermediates. This assignment is supported by an isotope shift in wave number. Effects of temperature, potential and deuterium substitution on the formation and disappearance of different adsorbed species (COad, adsorbed formate, adsorbed formyl), are monitored and quantified. Consequences on the mechanism for dissociative adsorption and oxidation of formaldehyde are discussed. PMID:24991512

  12. A Study of the Reactions of Ethanol on CeO 2 and Pd\\/CeO 2 by Steady State Reactions, Temperature Programmed Desorption, and In Situ FT-IR

    Microsoft Academic Search

    A. Yee; S. J. Morrison; H. Idriss

    1999-01-01

    The reaction of ethanol on unreduced and H2-reduced CeO2 and 1 wt% Pd\\/CeO2 has been investigated by steady state reactions, temperature programmed desorption (TPD), and in situ Fourier transform infrared (FT-IR) spectroscopy. Steady state reactions have shown a zero reaction order dependency for diatomic oxygen at and above 20%, whilst the addition of Pd to CeO2 decreases the apparent activation

  13. Kinetics study of heterogeneous reactions of ozone with erucic acid using an ATR-IR flow reactor.

    PubMed

    Leng, Chunbo; Hiltner, Joseph; Pham, Hai; Kelley, Judas; Mach, Mindy; Zhang, Yunhong; Liu, Yong

    2014-03-01

    The ozone initiated heterogeneous oxidation of erucic acid (EA) thin film was investigated using a flow system combined with attenuated total reflection infrared spectroscopy (ATR-IR) over wide ranges of ozone concentrations (0.25-60 ppm), thin film thickness (0.1-1.0 ?m), temperatures (263-298 K), and relative humidities (0-80% RH) for the first time. Pseudo-first-order rate constants, kapp, and overall reactive uptake coefficients, ?, were obtained through changes in the absorbance of C[double bond, length as m-dash]O stretching bands at 1695 cm(-1), which is assigned to the carbonyl group in carboxylic acid. Results showed that the reaction followed the Langmuir-Hinshelwood mechanism and kapp was largely dominated by surface reaction over bulk phase reaction. In addition, both the kapp and the ? values showed very strong temperature dependences (?two orders of magnitude) over the temperature range; in contrast, they only slightly increased with increasing RH values from 0-80%. According to the kapp values as a function of temperature, the activation energy for the heterogeneous reaction was estimated to be 80.6 kJ mol(-1). Our results have suggested that heterogeneous reactions between ozone and unsaturated solid surfaces likely have a substantially greater temperature dependence than liquid ones. Moreover, the hygroscopic properties of EA thin films before and after exposure to ozone were also studied by measurement of water uptake. Based on the hygroscopicity data, the insignificant RH effect on reaction kinetics was probably due to the relatively weak water uptake by the unreacted and reacted EA thin films. PMID:24457621

  14. Catalytic properties in n-heptane reforming of Pt–Sn and Pt–Ir–Sn\\/Al 2O 3 catalysts prepared by surface redox reaction

    Microsoft Academic Search

    Florence Epron; Christelle Carnevillier; Patrice Marécot

    2005-01-01

    Multimetallic Pt–Ir–Sn\\/Al2O3 catalysts, prepared by surface redox reaction, were tested in the conversion of n-heptane, used as model reaction of paraffin dehydrocyclization, under industrial-type conditions. Their catalytic performances were measured after 5 and 65h of reaction in order to evaluate the stability of the catalysts, and compared to those of a well-known Pt–Sn bimetallic catalyst as a function of the

  15. Preparation of trimetallic Pt–Re–Ge\\/Al 2O 3 and Pt–Ir–Ge\\/Al 2O 3 naphtha reforming catalysts by surface redox reaction

    Microsoft Academic Search

    Viviana Benitez; Marieme Boutzeloit; Vanina A. Mazzieri; Catherine Especel; Florence Epron; Carlos R. Vera; Patrice Marécot; Carlos L. Pieck

    2007-01-01

    Preparation of trimetallic Pt–Re–Ge\\/Al2O3 and Pt–Ir–Ge\\/Al2O3 naphtha reforming catalysts by means of a surface redox reaction (namely the catalytic reduction method), was studied by varying the concentration of Ge. The catalytic reduction method was chosen in order to favor the interaction of Ge with the active Pt–Re and Pt–Ir phases.The results shows that the deposition of Ge on the bimetallic

  16. Experimental study of the A(e,e{sup '}pi{sup +}) reaction on {sup 1}H, {sup 2}H, {sup 12}C, {sup 27}Al, {sup 63}Cu, and {sup 197}Au

    SciTech Connect

    Qian, X.; Gao, H.; Kramer, K. [Triangle Universities Nuclear Laboratory, Duke University, Durham, North Carolina (United States); Horn, T. [University of Maryland, College Park, Maryland (United States); Physics Division, TJNAF, Newport News, Virginia (United States); Clasie, B.; Seely, J. [Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, Massachusetts (United States); Arrington, J.; El Fassi, L.; Zheng, X. [Argonne National Laboratory, Argonne, Illinois (United States); Asaturyan, R.; Mkrtchyan, H.; Navasardyan, T.; Tadevosyan, V. [Yerevan Physics Institute, Yerevan (Armenia); Benmokhtar, F. [University of Maryland, College Park, Maryland (United States); Boeglin, W.; Markowitz, P. [Florida International University, Miami, Florida (United States); Bosted, P.; Bruell, A.; Chudakov, E.; Ent, R. [Physics Division, TJNAF, Newport News, Virginia (United States)

    2010-05-15

    Cross sections for the {sup 1}H(e,e{sup '}pi{sup +})n process on {sup 1}H, {sup 2}H, {sup 12}C, {sup 27}Al, {sup 63}Cu, and {sup 197}Au targets were measured at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) to extract nuclear transparencies. Data were taken from Q{sup 2}=1.1-4.7 GeV{sup 2} for a fixed center-of-mass energy of W=2.14 GeV. The ratio of sigma{sub L} and sigma{sub T} was extracted from the measured cross sections for {sup 1}H, {sup 2}H, {sup 12}C, and {sup 63}Cu targets at Q{sup 2}=2.15 and 4.0 GeV{sup 2}, allowing for additional studies of the reaction mechanism. In this article, we present the experimental setup and the analysis of the data in detail, including systematic uncertainty studies. Differential cross sections and nuclear transparencies as a function of the pion momentum at different values of Q{sup 2} are presented. Our results are consistent with the predicted early onset of color transparency in mesons. Global features of the data are discussed and the data are compared with model calculations for the {sup 1}H(e,e{sup '}pi{sup +})n reaction from nuclear targets.

  17. Kinetic study of the reaction CH(X 2&Pgr;)+H2&rlarr2;CH2(X 3B1)+H in the temperature range 372 to 675 K

    Microsoft Academic Search

    S. Zabarnick; J. W. Fleming; M. C. Lin

    1986-01-01

    The reaction CH(X 2&Pgr;)+H2&rlarr2;CH2(X 3B1)+H was studied over the temperature range 372 to 675 K. Laser-induced fluorescence detection of CH radicals allowed direct determination of absolute rate constants for the forward reaction k1. The data are well fit by the Arrhenius expression k1=(2.38±0.31)×10?10 exp[?(1760±60)\\/T] cm3\\/s over the temperature range studied. A transition state theory (RRKM) calculation yields the following form

  18. Effect of collision energy on the reaction mechanism of C((3)P)?+?OH(X(2) ?)???CO(X(1) ?(+))?+?H((2)S).

    PubMed

    Huang, Yanru

    2015-04-01

    Quasiclassical trajectory calculations based on a fully global ab initio potential energy surface of the rotational angular momentum polarisation of the product CO in the title reaction are reported. The alignment and orientation of the rotational angular momentum of the CO fragment in the scattering frame were found to be sensitive to the initial collision energy chosen. Differences in the angular momentum polarization at different collision energies were traced to differences in the microscopic reaction mechanism. The results of this study suggest that the title reaction is mainly dominated by an abstraction reaction mechanism (involving the short-lived and metastable intermediate complex COH) at low collision energies; however, at relatively high energies, an insertion reaction mechanism (involving the long-lived and stable intermediate complex HCO) plays a role. PMID:25832797

  19. Selective Access to 3-Cyano-1H-indoles, 9H-Pyrimido[4,5-b]indoles, or 9H-Pyrido[2,3-b]indoles through Copper-Catalyzed One-Pot Multicomponent Cascade Reactions.

    PubMed

    Li, Bin; Guo, Shenghai; Zhang, Ju; Zhang, Xinying; Fan, Xuesen

    2015-06-01

    Novel and selective synthetic approaches toward indole derivatives via copper-catalyzed one-pot multicomponent cascade reactions of 1-bromo-2-(2,2-dibromovinyl)benzenes with aldehydes and aqueous ammonia are presented. Intriguingly, the concentration of ammonia, the molar ratio of reagents, and the structural features of the aldehyde substrate serve as key factors in controlling the selective formation of 3-cyano-1H-indoles, 9H-pyrimido[4,5-b]indoles, or 9H-pyrido[2,3-b]indoles. Compared with literature procedures, the synthetic approaches reported herein have advantages such as readily available starting materials, mild reaction conditions, and divergent reaction patterns toward different products with easily tunable selectivity. PMID:25984799

  20. FT-IR and theoretical study of 3,5-dimethyl-1H-pyrazole-1-carboxamidine (L) and the complexes CoL2(H2O)2(NO3)2, NiL2(H2O)2(NO3)2.

    PubMed

    Pogány, Peter; Kovács, Attila; Szécsényi, Katalin Mészáros; Leovac, Vukadin M

    2008-12-15

    In the paper a joint experimental and theoretical study of 3,5-dimethyl-1H-pyrazole-1-carboxamidine (L) as well as its complexes CoL2(H2O)2(NO3)2 and NiL2(H2O)2(NO3)2 is reported. On the basis of FT-IR experiments and a DFT-derived scaled quantum mechanical force field the normal coordinate analysis of L was carried out. The FT-IR spectra of the two complexes were interpreted using the present assignment of L and computed vibrational data of the complexes. The ionic and charge transfer interactions in the complexes were assessed by means of natural bond orbital (NBO) analysis. PMID:18562246

  1. Charged pion form factor between Q{sup 2} = 0.60 and 2.45 GeV{sup 2}. I. measurements of the cross section for the {sup 1}H(e,e'{pi}{sup +}n reaction.

    SciTech Connect

    Blok, H. P.; Horn, T.; Huber, G. M.; Beise, E. J.; Gaskell, D.; Arrington, J.; Holt, R. J.; Jackson, H.; Mueller, B.; Potterveld, D.; Reimer, P.; Zheng, X.; Jefferson Lab. Fx Collaboration; Physics; VU Univ.; NIKHEF; Univ. of Maryland; Jefferson Lab.; Univ. of Regina

    2008-01-01

    Cross sections for the reaction {sup 1}H(e,e'{Pi}{sup +})n were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using the high-intensity Continuous Electron Beam Accelerator Facility (CEBAF) to determine the charged pion form factor. Data were taken for central four-momentum transfers ranging from Q{sup 2} = 0.60 to 2.45 GeV{sup 2} at an invariant mass of the virtual photon-nucleon system of W = 1.95 and 2.22 GeV. The measured cross sections were separated into the four structure functions {sigma}{sub L},{sigma}{sub T}, {sigma}{sub LT}, and {sigma}{sub TT}. The various parts of the experimental setup and the analysis steps are described in detail, including the calibrations and systematic studies, which were needed to obtain high-precision results. The different types of systematic uncertainties are also discussed. The results for the separated cross sections as a function of the Mandelstam variable t at the different values of Q{sup 2} are presented. Some global features of the data are discussed, and the data are compared with the results of some model calculations for the reaction {sup 1}H(e,e'{Pi}{sup +})n.

  2. Charged pion form factor between Q2=0.60 and 2.45 GeV2. I. Measurements of the cross section for the 1H(e,e'?+)n reaction

    NASA Astrophysics Data System (ADS)

    Blok, H. P.; Horn, T.; Huber, G. M.; Beise, E. J.; Gaskell, D.; Mack, D. J.; Tadevosyan, V.; Volmer, J.; Abbott, D.; Aniol, K.; Anklin, H.; Armstrong, C.; Arrington, J.; Assamagan, K.; Avery, S.; Baker, O. K.; Barrett, B.; Bochna, C.; Boeglin, W.; Brash, E. J.; Breuer, H.; Chang, C. C.; Chant, N.; Christy, M. E.; Dunne, J.; Eden, T.; Ent, R.; Fenker, H.; Gibson, E.; Gilman, R.; Gustafsson, K.; Hinton, W.; Holt, R. J.; Jackson, H.; Jin, S.; Jones, M. K.; Keppel, C. E.; Kim, P. H.; Kim, W.; King, P. M.; Klein, A.; Koltenuk, D.; Kovaltchouk, V.; Liang, M.; Liu, J.; Lolos, G. J.; Lung, A.; Margaziotis, D. J.; Markowitz, P.; Matsumura, A.; McKee, D.; Meekins, D.; Mitchell, J.; Miyoshi, T.; Mkrtchyan, H.; Mueller, B.; Niculescu, G.; Niculescu, I.; Okayasu, Y.; Pentchev, L.; Perdrisat, C.; Pitz, D.; Potterveld, D.; Punjabi, V.; Qin, L. M.; Reimer, P.; Reinhold, J.; Roche, J.; Roos, P. G.; Sarty, A.; Shin, I. K.; Smith, G. R.; Stepanyan, S.; Tang, L. G.; Tvaskis, V.; van der Meer, R. L. J.; Vansyoc, K.; Westrum, D. Van; Vidakovic, S.; Vulcan, W.; Warren, G.; Wood, S. A.; Xu, C.; Yan, C.; Zhao, W.-X.; Zheng, X.; Zihlmann, B.

    2008-10-01

    Cross sections for the reaction 1H(e,e'?+)n were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using the high-intensity Continuous Electron Beam Accelerator Facility (CEBAF) to determine the charged pion form factor. Data were taken for central four-momentum transfers ranging from Q2=0.60 to 2.45 GeV2 at an invariant mass of the virtual photon-nucleon system of W=1.95 and 2.22 GeV. The measured cross sections were separated into the four structure functions ?L,?T,?LT, and ?TT. The various parts of the experimental setup and the analysis steps are described in detail, including the calibrations and systematic studies, which were needed to obtain high-precision results. The different types of systematic uncertainties are also discussed. The results for the separated cross sections as a function of the Mandelstam variable t at the different values of Q2 are presented. Some global features of the data are discussed, and the data are compared with the results of some model calculations for the reaction 1H(e,e'?+)n.

  3. Quantum mechanical study of the structure and spectroscopic (FT-IR, FT-Raman, 13C, 1H and UV), NBO and HOMO-LUMO analysis of 2-quinoxaline carboxylic acid.

    PubMed

    Prabavathi, N; Nilufer, A; Krishnakumar, V

    2012-06-15

    The FTIR and FT-Raman spectra of 2-quinoxaline carboxylic acid (2-QCA) has been recorded in the region 4000-450 and 4000-100 cm(-1), respectively. The conformational analysis, optimized geometry, frequency and intensity of the vibrational bands of 2-QCA were obtained by the density functional theory (DFT) with complete relaxation in the potential energy surface using 6-31G(d) basis set. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FTIR and FT-Raman spectra. The observed and the calculated frequencies are found to be in good agreement. The (1)H and(13)C NMR spectra have been recorded and (1)H and (13)C nuclear magnetic resonance chemical shifts of the molecule were also calculated using the gauge independent atomic orbital (GIAO) method and their respective linear correlations were obtained. The theoretical UV-visible spectrum of the compound using CIS method and the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule. The Mulliken charges, the values of electric dipole moment (?) of the molecule were computed using DFT calculations. The change in electron density (ED) in the ?* antibonding orbitals and stabilization energies E(2) have been calculated by natural bond (NBO) analysis to give clear evidence of stabilization originating in the hyper conjugation of hydrogen-bonded interactions. PMID:22446782

  4. Synthesis, NMR, FT-IR, X-ray structural characterization, DFT analysis and isomerism aspects of 5-(2,6-dichlorobenzylidene)pyrimidine-2,4,6(1H,3H,5H)-trione

    NASA Astrophysics Data System (ADS)

    Barakat, Assem; Al-Najjar, Hany J.; Al-Majid, Abdullah Mohammed; Soliman, Saied M.; Mabkhot, Yahia Nasser; Shaik, Mohammed Rafi; Ghabbour, Hazem A.; Fun, Hoong-Kun

    2015-08-01

    The synthesis and spectral characterization of the 5-(2,6-dichlorobenzylidene)pyrimidine-2,4,6(1H,3H,5H)-trione;3 was reported. The solid state molecular structure of 3 was studied using X-ray crystallography. The relative stabilities of the seven possible isomers of 3 were calculated by DFT/B3LYP method using 6-311G(d,p) basis set. The calculated total energies and thermodynamic parameters were used to predict the relative stabilities of these isomers. The effect of solvent polarity on the relative stability of these isomers was studied at the same level of theory using PCM. It was found that the keto form, (T0), is the most stable isomer both in the gaseous state and solution. In solution, the calculated total energies of all isomers are decreased indicating that all isomers are stabilized by the solvent effect. The vibrational spectra of the most stable isomer, 3(T0) are calculated using the same level of theory and the results are compared with the experimentally measured FTIR spectra. Good correlation was obtained between the experimental and calculated vibrational frequencies (R2 = 0.9992). The electronic spectra of 3(T0) in gas phase as well as in solutions were calculated using the TD-DFT method. All the predicted electronic transitions showed very little spectral shifts and increase in the intensity of absorption due to solvent effect. Also the 1H- and 13C-NMR chemical shifts of the stable isomer were calculated and the results were correlated with the experimental data. Good correlations between the experimental and calculated chemical shifts were obtained.

  5. Comparative study for separation of atmospheric humic-like substance (HULIS) by ENVI-18, HLB, XAD-8 and DEAE sorbents: elemental composition, FT-IR, 1H NMR and off-line thermochemolysis with tetramethylammonium hydroxide (TMAH).

    PubMed

    Fan, Xingjun; Song, Jianzhong; Peng, Ping'an

    2013-11-01

    Humic-like substances (HULIS) are significant constituents of aerosols, and the isolation and characterization of HULIS by solid-phase extraction methods are dependent on the sorbents used. In this study, we used the following five methods: ENVI-18, HLB-M, HLB-N, XAD-8 and DEAE, to isolate atmospheric HULIS at an urban site. Then we conducted a comparative investigation of the HULIS chemical characteristics by means of elemental analysis, Fourier transform infrared spectroscopy, (1)H nuclear magnetic resonance spectroscopy and off-line thermochemolysis with tetramethylammonium hydroxide. The results indicate that HULIS isolated using different methods show many similarities in chemical composition and structure. Some differences were however also observed between the five isolated HULIS: HULISHLB-M contains a relatively high content of OCH group, compared to HULISENVI-18 and HULISXAD-8; HULISXAD-8 contains a relatively high content of hydrophobic and aromatic components, compared to HULISENVI-18 and HULISHLB-M; HULISDEAE contains the highest content of aromatic functional groups, as inferred by (1)H NMR spectra, but a great amount of salts generally present in the HULISDEAE and thereby limited the choices for characterizing the materials (i.e., elemental analysis and TMAH thermochemolysis); HULISHLB-N has relatively high levels of H and N, a high N/C atomic ratio, and includes N-containing functional groups, which suggests that it has been altered by 2% ammonia introduced in the eluents. In summary, we found that ENVI-18, HLB-M, and XAD-8 are preferable methods for isolation and characterization of HULIS in atmospheric aerosols. These results also suggest that caution is required when applying DEAE and HLB-N isolating methods for characterizing atmospheric HULIS. PMID:23773442

  6. Synthesis, NMR, FT-IR, X-ray structural characterization, DFT analysis and isomerism aspects of 5-(2,6-dichlorobenzylidene)pyrimidine-2,4,6(1H,3H,5H)-trione.

    PubMed

    Barakat, Assem; Al-Najjar, Hany J; Al-Majid, Abdullah Mohammed; Soliman, Saied M; Mabkhot, Yahia Nasser; Shaik, Mohammed Rafi; Ghabbour, Hazem A; Fun, Hoong-Kun

    2015-08-01

    The synthesis and spectral characterization of the 5-(2,6-dichlorobenzylidene)pyrimidine-2,4,6(1H,3H,5H)-trione;3 was reported. The solid state molecular structure of 3 was studied using X-ray crystallography. The relative stabilities of the seven possible isomers of 3 were calculated by DFT/B3LYP method using 6-311G(d,p) basis set. The calculated total energies and thermodynamic parameters were used to predict the relative stabilities of these isomers. The effect of solvent polarity on the relative stability of these isomers was studied at the same level of theory using PCM. It was found that the keto form, (T0), is the most stable isomer both in the gaseous state and solution. In solution, the calculated total energies of all isomers are decreased indicating that all isomers are stabilized by the solvent effect. The vibrational spectra of the most stable isomer, 3(T0) are calculated using the same level of theory and the results are compared with the experimentally measured FTIR spectra. Good correlation was obtained between the experimental and calculated vibrational frequencies (R(2)=0.9992). The electronic spectra of 3(T0) in gas phase as well as in solutions were calculated using the TD-DFT method. All the predicted electronic transitions showed very little spectral shifts and increase in the intensity of absorption due to solvent effect. Also the (1)H- and (13)C-NMR chemical shifts of the stable isomer were calculated and the results were correlated with the experimental data. Good correlations between the experimental and calculated chemical shifts were obtained. PMID:25827772

  7. Measurements of the neutron electric to magnetic form factor ratio GEn/GMn via the ^2H(\\vec{e},e'\\vec{n})^1H reaction to Q^2 = 1.45 (GeV/c)^2

    E-print Network

    Jefferson Laboratory E93-038 Collaboration; :; B. Plaster; A. Yu. Semenov

    2005-11-13

    We report values for the neutron electric to magnetic form factor ratio, GEn/GMn, deduced from measurements of the neutron's recoil polarization in the quasielastic 2H(\\vec{e},e'\\vec{n})1H reaction, at three Q^2 values of 0.45, 1.13, and 1.45 (GeV/c)^2. The data at Q^2 = 1.13 and 1.45 (GeV/c)^2 are the first direct experimental measurements of GEn employing polarization degrees of freedom in the Q^2 > 1 (GeV/c)^2 region and stand as the most precise determinations of GEn for all values of Q^2.

  8. Molecular structure, FT-IR, vibrational assignments, HOMO-LUMO analysis and molecular docking study of 1-[5-(4-Bromophenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl]ethanone.

    PubMed

    Mary, Y Sheena; Panicker, C Yohannan; Sapnakumari, M; Narayana, B; Sarojini, B K; Al-Saadi, Abdulaziz A; Van Alsenoy, Christian; War, Javeed Ahmad; Fun, H K

    2015-02-01

    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 1-[5-(4-bromophenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl]ethanone have been investigated experimentally and theoretically using Gaussian09 software package. The title compound was optimized using the HF/6-31G(d) (6D, 7F), B3LYP/6-31G (6D, 7F) and B3LYP/6-311++G(d,p) (5D, 7F) calculations. The B3LYP/6-311++G(d,p) (5D, 7F) results and in agreement with experimental infrared bands. The geometrical parameters are in agreement with XRD data. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. Molecular electrostatic potential was also performed. From the MEP it is evident that the negative charge covers the C=O group and the positive region is over the rings. First hyperpolarizability is calculated in order to find its role in nonlinear optics. Molecular docking studies suggest that the compound might exhibit inhibitory activity against TPII and may act as anti-neoplastic agent. PMID:25448948

  9. Spatially resolved in situ determination of reaction progress using microfluidic systems and FT-IR spectroscopy as a tool for biocatalytic process development.

    PubMed

    Fagaschewski, Janosch; Sellin, Daniel; Wiedenhöfer, Charles; Bohne, Sven; Trieu, Hoc K; Hilterhaus, Lutz

    2015-07-01

    A concept for the determination of concentrations in microchannels using FT-IR spectroscopy in transmission is presented. The fundamental idea of spatially resolved measurements along several measuring points was implemented in a single-channel microreactor. Compared to existing microreactor setups for the analysis of fast chemical reactions or mixing processes, the presented concept enables longer residence times at appropriate resolution. Once steady-state conditions were reached in the reactor, mid-infrared spectra were collected at different locations. Information throughout the considered conversion range is available, which is of great importance to analyze inhibitory effects, next to the kinetic constants (v max and K M). Therefore, this technology enables a rapid screening of (bio-)catalysts, substrate specificity and process conditions. In particular, the analysis of real substrates instead of model substrates and the possibility to follow side reactions and follow-up reactions during enzymatic catalysis open a broad field of application. PMID:25732540

  10. Glycyl-histidyl-lysine (GHK) is a quencher of alpha,beta-4-hydroxy-trans-2-nonenal: a comparison with carnosine. insights into the mechanism of reaction by electrospray ionization mass spectrometry, 1H NMR, and computational techniques.

    PubMed

    Beretta, Giangiacomo; Artali, Roberto; Regazzoni, Luca; Panigati, Monica; Facino, Roberto Maffei

    2007-09-01

    Histidine-containing oligopeptides are currently studied as detoxifying agents against cytotoxic alpha,beta-unsaturated aldehydes (prototype: 4-hydroxy-2-nonenal, HNE), electrophilic end products formed by decomposition of omega-6 polyunsaturated fatty acids, associated with severe pathologies such as diabetes, nephropathy, retinopathy, and neurodegenerative diseases. This study evaluated the quenching reaction against HNE of the endogenous tripeptide l-glycyl- l-histidyl- l-lysine (GHK), an oligopeptide discovered to be a growth-modulating factor and also a strong activator of wound healing. We first evaluated the HNE consumption (50 microM, HPLC-UVDAD method) in the presence of GHK (1 mM) in physiomimetic conditions (phosphate buffer, pH 7.4) and confirmed GHK/HNE adduct formation by mass spectrometric analysis (ESI-MS/MS) and (1)H NMR analyses. These results indicated that GHK was an effective quencher of HNE, although significantly less potent than the reference compound carnosine, and that HNE modulation by GHK can contribute to the satisfactory outcome of the wound-healing process. In the second part of the study, we investigated the quenching reaction between GHK and HNE, in parallel to carnosine, using (1)H NMR and computational analyses. At a mechanistic level, this explained the different reactivity of the two peptides: (i) The greater stability of the macrocyclic intermediate HNE/carnosine was compared to HNE/GHK. (ii) GHK in solution has a quasi-folded conformation due to the interaction of four intramolecular hydrogen bonds, three of which need to be broken for the transition state to form (energy barrier, approximately 20 kcal/mol). By contrast, carnosine, with an extended conformation and only one hydrogen bond, requires less energy to reach the transition state ( approximately 7 kcal/mol). (iii) The different stereoelectronic features of the transition state lead to the intramolecular Michael reaction, that is, the favorable superimposition of carnosine highest occupied molecular orbital and the HNE lowest unoccupied molecular orbital, in relation to the unfavorable orbital configuration of GHK. The overall findings provide interesting and useful insights into the mechanisms of interaction of both GHK and carnosine with HNE and illustrate the utility of computational studies for defining the (optimal) chemical and structural parameters for an optimal quenching of alpha,beta-unsaturated aldehydes. PMID:17672515

  11. Measurement of the 187Re({\\alpha},n)190Ir reaction cross section at sub-Coulomb energies using the Cologne Clover Counting Setup

    E-print Network

    Scholz, P; Hennig, A; Netterdon, L; Becker, H W; Endres, J; Mayer, J; Giesen, U; Rogalla, D; Schlüter, F; Pickstone, S G; Zell, K O; Zilges, A

    2015-01-01

    Uncertainties in adopted models of particle+nucleus optical-model potentials directly influence the accuracy in the theoretical predictions of reaction rates as they are needed for reaction-network calculations in, for instance, {\\gamma}-process nucleosynthesis. The improvement of the {\\alpha}+nucleus optical-model potential is hampered by the lack of experimental data at astrophysically relevant energies especially for heavier nuclei. Measuring the Re187({\\alpha},n)Ir190 reaction cross section at sub-Coulomb energies extends the scarce experimental data available in this mass region and helps understanding the energy dependence of the imaginary part of the {\\alpha}+nucleus optical-model potential at low energies. Applying the activation method, after the irradiation of natural rhenium targets with {\\alpha}-particle energies of 12.4 to 14.1 MeV, the reaction yield and thus the reaction cross section were determined via {\\gamma}-ray spectroscopy by using the Cologne Clover Counting Setup and the method of {\\ga...

  12. Charged pion form factor between $Q^2$=0.60 and 2.45 GeV$^2$. I. Measurements of the cross section for the ${^1}$H($e,e'\\pi^+$)$n$ reaction.

    SciTech Connect

    Blok, Henk; Horn, Tanja; Huber, Garth; Beise, Elizabeth; Gaskell, David; Mack, David; Tadevosyan, Vardan; Volmer, Jochen; Abbott, David; Aniol, Konrad; Anklin, Heinz; Armstrong, Christopher; Arrington, John; Assamagan, Ketevi; Avery, Steven; Baker, O.; Barrett, Robert; Bochna, Christopher; Boeglin, Werner; Brash, Edward; Breuer, Herbert; Chang, C.; Chang, C.C.; Chant, Nicholas; Christy, Michael; Dunne, James; Eden, Thomas; Ent, Rolf; Fenker, Howard; Gibson, Edward; Gilman, Ronald; Gustafsson, Kenneth; Hinton, Wendy; Holt, Roy; Jackson, Harold; uk Jin, Seong; Jones, Mark; Keppel, Cynthia; Kim, pyunghun; Kim, Wooyoung; King, Paul; Klein, Andreas; Koltenuk, Douglas; Kovaltchouk, Vitali; Liang, Meihua; Liu, Jinghua; Lolos, George; Lung, Allison; Margaziotis, Demetrius; Markowitz, Pete; Matsumura, Akihiko; McKee, David; Meekins, David; Mitchell, Joseph; Miyoshi, Toshinobu; Mkrtchyan, Hamlet; Mueller, Robert; Niculescu, Gabriel; Niculescu, Maria-Ioana; Okayasu, Yuichi; Pentchev, Lubomir; Perdrisat, Charles; Pitz, David; Potterveld, David; Punjabi, Vina; Qin, Liming; Reimer, Paul; Reinhold, Joerg; Roche, Julie; Roos, Philip; Sarty, Adam; Shin, Ilkyoung; Smith, Gregory; Stepanyan, Stepan; Tang, Liguang; Tvaskis, Vladas; van der Meer, Rob; Vansyoc, Kelley; Van Westrum, Derek; Vidakovic, Sandra; Vulcan, William; Warren, Glen; Wood, Stephen; Xu, C.; Yan, Chen; Zhao, Wenxia; Zheng, Xiaochao; Zihlmann, Benedikt

    2008-10-01

    DOI: http://dx.doi.org/10.1103/PhysRevC.78.045202
    Cross sections for the reaction 1H(e,e'pi+)n were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using the high-intensity Continuous Electron Beam Accelerator Facility (CEBAF) to determine the charged pion form factor. Data were taken for central four-momentum transfers ranging from Q2=0.60 to 2.45 GeV2 at an invariant mass of the virtual photon-nucleon system of W=1.95 and 2.22 GeV. The measured cross sections were separated into the four structure functions sigmaL,sigmaT,sigmaLT, and sigmaTT. The various parts of the experimental setup and the analysis steps are described in detail, including the calibrations and systematic studies, which were needed to obtain high-precision results. The different types of systematic uncertainties are also discussed. The results for the separated cross sections as a function of the Mandelstam variable t at the different values of Q2 are presented. Some global featu

  13. Synthesis, crystal structure and biological activity of 1-(1 H-benzoimidazol-2-yl)-ethanone thiosemicarbazone and its cobalt complex

    Microsoft Academic Search

    Mehmet Poyraz; Musa Sari; Fatih Demirci; Muberra Kosar; Seref Demirayak; Orhan Büyükgüngör

    2008-01-01

    1-(1H-Benzoimidazol-2-yl)-ethanone thiosemicarbazone (H2L) (1) was obtained by the condensation reaction of 2-acetylbenzimidazole, thiosemicarbazide and acetic acid in ethanol. The novel cobalt(III) complex [Co(L)(HL)] 2 was prepared by the direct reaction of CoCl2·6H2O with the ligand H2L. The reaction products were characterized by elemental analysis, thermogravimetric analysis (TGA), FT-IR and mass spectrometry for H2L, and magnetic measurement for the Co(III) complex.

  14. In-situ characterization of the cure reaction of HTPB and IPDI by simultaneous NMR and IR measurements

    Microsoft Academic Search

    K. Hailu; G. Guthausen; W. Becker; A. König; A. Bendfeld; E. Geissler

    2010-01-01

    The progress of the cure reaction of hydroxyl-terminated (poly)butadiene (HTPB) and isophorone diisocyanate (IPDI) to a polyurethane is of major importance for the adjustment of process parameters as well as final product properties. Simultaneous low field nuclear magnetic resonance relaxometry and near infrared spectroscopy are applied in-situ to study the progress of the cure reaction with respect to time. The

  15. Acknowledgement Determination of the authenticity of commercial coffees using 1H

    E-print Network

    Ferreira, Márcia M. C.

    Acknowledgement ! " Determination of the authenticity of commercial coffees using 1H NMR, FT-IR spectra and chemometrics Determination of the authenticity of commercial coffees usingDetermination of the authenticity of commercial coffees using 11 HH NMR, FT-IR spectra andNMR, FT-IR spectra

  16. The first structural determination of a Copper (II) complex containing the ligand [1-(4-((1H-benzo[d][1,2,3]triazol-2(3H)-yl)methyl)benzyl)-1H-benzo[d][1,2,3]triazole

    Microsoft Academic Search

    George E. Kostakis; Pantelis Xydias; Ebbe Nordlander; John C. Plakatouras

    The reaction of the ligand [1-(4-((1H-benzo[d][1,2,3]triazol-2(3H)-yl)methyl)benzyl)-1H-benzo[d][1,2,3]triazole] (L) with CuCl2 in acetonitrile yields a dinuclear copper (II) complex [Cu2Cl4L2] · 2CH3CN (1 ·2CH3CN), which has been characterized by elemental analysis, powder and single crystal X-ray diffraction, thermal gravimetric analysis as well as IR, UV-Vis and EPR spectroscopy The crystal structure reveals that the metal coordination geometry is best described as square

  17. Probing Mobility-Selected Saccharide Isomers: Selective Ion-Molecule Reactions and Wavelength-Specific IR Activation.

    PubMed

    Hernandez, Oscar; Isenberg, Samantha; Steinmetz, Vincent; Glish, Gary L; Maitre, Philippe

    2015-06-11

    Differential Ion Mobility Spectrometry (DIMS) provides orthogonal separation to mass spectrometry, and DIMS combined with the high sensitivity of a quadrupole ion-trap is shown to be useful for the separation and identification of saccharides. A comprehensive analysis of the separation of anomers (?- and ?-methylated glucose) and epimers (?-methylated glucose and mannose) ionized with Li(+), Na(+), and K(+) is performed. DIMS separation is found to be better for saccharides cationized with the two latter species. The corresponding resolving power for the two glucose anomers with Na(+) is found to be very close to the corresponding drift-tube IMS value. The lithiated complexes are investigated further using a combination of infrared spectroscopy integrated to ion-trap mass spectrometry and quantum chemical calculations. Together with DIMS, consistent results are obtained. It is found that two competing structural motifs might be at play, depending on the subtle balance between the maximization of the coordination of the metal cation and the intrinsic conformational energetics of the saccharide, which is for a large part driven by hydrogen bonding. The comparison of simulated and observed spectra clearly shows that a band at ?3400 cm(-1) is specific to a structural motif found in the lithiated glucose complexes, which could explain the trends observed in the DIMS spectra of the saccharide complexes. It is shown that DIMS-MS/MS using wavelength specific IR activation would provide a new orthogonal dimension to mass spectrometry. PMID:25827317

  18. Coordination chemistry of the soft chiral Lewis acid [Cp*Ir(TsDPEN)]+.

    PubMed

    Letko, Christopher S; Heiden, Zachariah M; Rauchfuss, Thomas B; Wilson, Scott R

    2011-06-20

    The paper surveys the binding of anions to the unsaturated 16e Lewis acid [Cp*Ir(TsDPEN)](+) ([1H](+)), where TsDPEN is racemic H(2)NCHPhCHPhNTs(-). The derivatives Cp*IrX(TsDPEN) were characterized crystallographically for X(-) = CN(-), Me(C?NH)S(-), NO(2)(-), 2-pyridonate, and 0.5 MoS(4)(2-). [(1H)(2)(?-CN)](+) forms from [1H](+) and 1H(CN). Aside from 2-pyridone, amides generally add reversibly and bind to Ir through N. Thioacetamide binds irreversibly through sulfur. Compounds of the type Cp*IrX(TsDPEN) generally form diastereoselectively, although diastereomeric products were observed for the strong ligands (X = CN(-), H(-) (introduced via BH(4)(-)), or Me(C?NH)S(-)). Related experiments on the reaction (p-cymene)Ru(TsDPEN-H) + BH(4)(-) gave two diastereomers of (p-cymene)RuH(TsDPEN), the known hydrogenation catalyst and a second isomer that hydrogenated acetophenone more slowly. These experiment provide new insights into the enantioselectivity of these catalysts. Diastereomerization in all cases was first order in metal with modest solvent effects. The diphenyl groups are generally diequatorial for the stable diastereomers. For the 2-pyridonate adduct, axial phenyl groups are stabilized in the solid state by puckering of the IrN(2)C(2) ring induced by intramolecular hydrogen-bonding. Crystallographic analysis of [Cp*Ir(TsDPEN)](2)(MoS(4)) revealed a unique example of a ?(1),?(1)-tetrathiometallate ligand. Cp*Ir(SC(NH)Me)TsDPEN) is the first example of a ?(1)-S-thioamidato complex. PMID:21574553

  19. Esterification of cellulose with acyl-1 H -benzotriazole

    Microsoft Academic Search

    Matilde C. V. Nagel; Thomas Heinze

    2010-01-01

    For the first time, the acylation of cellulose was realized by activation of carboxylic acid with 1H-benzotriazole. The reaction could be carried out under mild conditions. The acyl-1H-benzotriazole reacts with cellulose leading to cellulose acetate, butyrate, caproate, benzoate, myristate, and stearate with\\u000a DS values between 1.07 and 1.89. The reaction proceeds completely homogeneously in dimethyl sulfoxide (DMSO)\\/TBAF × 3H2O (tetrabutylammonium fluoride trihydrate)

  20. Density functional theory (DFT) and natural bond orbital (NBO) investigation of intramolecular hydrogen bond interaction and excited-state intramolecular proton transfer (ESIPT) reaction in a five-membered hydrogen-bonding system 2-(1 H-pyrazol-5-yl)pyridine: On the possibility of solvent (water)-assisted ESPT

    Microsoft Academic Search

    Bijan Kumar Paul; Nikhil Guchhait

    2011-01-01

    The present work aims at exploring the excited-state intramolecular proton transfer (ESIPT) reaction in a five-member hydrogen bonding ring system, viz., 2-(1H-pyrazol-5-yl)pyridine (2Pz–5Py), in which the ESIPT process is found to be associated with an appreciably large barrier, on the lexicon of a Density Functional Theory (DFT)-based computational approach. Nevertheless the feasibility of ESIPT has been argued from the changeover

  1. Two different products from the reaction of 1-aryl-5-chloro-3-methyl-1H-pyrazole-4-carbaldehyde with cyclohexylamine when the aryl substituent is phenyl or pyridin-2-yl: hydrogen-bonded sheets versus dimers.

    PubMed

    Orrego Hernandez, Jessica; Portilla, Jaime; Cobo, Justo; Glidewell, Christopher

    2015-05-01

    Cyclohexylamine reacts with 5-chloro-3-methyl-1-(pyridin-2-yl)-1H-pyrazole-4-carbaldehyde to give 5-cyclohexylamino-3-methyl-1-(pyridin-2-yl)-1H-pyrazole-4-carbaldehyde, C16H20N4O, (I), formed by nucleophilic substitution, but with 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde the product is (Z)-4-[(cyclohexylamino)methylidene]-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one, C17H21N3O, (II), formed by condensation followed by hydrolysis. Compound (II) crystallizes with Z' = 2, and in one of the two independent molecular types the cyclohexylamine unit is disordered over two sets of atomic sites having occupancies of 0.65?(3) and 0.35?(3). The vinylogous amide portion in each compound shows evidence of electronic polarization, such that in each the O atom carries a partial negative charge and the N atom of the cyclohexylamine portion carries a partial positive charge. The molecules of (I) contain an intramolecular N-H...N hydrogen bond, and they are linked by C-H...O hydrogen bonds to form sheets. Each of the two independent molecules of (II) contains an intramolecular N-H...O hydrogen bond and each molecular type forms a centrosymmetric dimer containing one R2(2)(4) ring and two inversion-related S(6) rings. PMID:25940891

  2. Bis(3-pyridyl)methylvinylsilane ( L1) and 1,2-di(3-quinolyl) dimethyl disilane ( L2): Synthesis and complexation reactions. Anion controlled solid state structures of cationic Ag(I)– L1 complex

    Microsoft Academic Search

    Neetu Rani; G. K. Rao; Ajai K. Singh

    2009-01-01

    3-Bromopyridine and 3-bromoquinoline on reaction with n-butyllithium give lithiated products which on reaction with dichloromethylvinylsilane and 1,2-dichlorodimethyldisilane at ?78°C result in the ligands bis(3-pyridyl)methylvinylsilane (L1) and 1,2-di(3-quinolyl)dimethyl disilane (L2). The complexation reactions of both these ligands with Ag(I), Pd(II) and Cu(II) have been explored. The 1H, 13C{1H} and 29Si{1H}NMR and IR spectra of both the ligands and their metal complexes

  3. IR SensorsIR Sensors IR Sensor ApplicationsIR Sensor Applications

    E-print Network

    La Rosa, Andres H.

    light off ofIR light off of target to Detectortarget to Detector #12;QRB1134: Reflective IR SensorQRB1134: Reflective IR Sensor Diode Emits IR lightDiode Emits IR light IR light reflects off of surfaceIR SensorsIR Sensors #12;IR Sensor ApplicationsIR Sensor Applications Security/Motion Detector

  4. Coal gasification reactions with on-line in-situ FT-IR analysis. Twelfth quarterly report, June 3September 3, 1984

    Microsoft Academic Search

    P. R. Solomon; M. A. Serio; D. G. Hamblen; P. E. Best; J. R. Markham

    1984-01-01

    During the twelfth quarter, the main thrust was determination of coal pyrolysis kinetics in the heated tube reactor. This involved measurement of particle temperature using FT-IR transmission and emission spectroscopy, residence time determinations with photodiodes, material balances, and FT-IR analysis of chars. The particle temperatures determined by FT-IR were generally close to those estimated from a knowledge of the gas

  5. Ir/IrSi3/Si Schottky-Barrier Infrared Detector

    NASA Technical Reports Server (NTRS)

    Lin, True-Lon

    1991-01-01

    Quantum efficiency increased. Proposed Schottky-barrier infrared detector has double metallic layer of Ir and IrSi3 instead of single metallic layer of Ir, IrSi, or IrSi3. Offers advantages of both relatively high infrared absorption in thin film of Ir and stability and reproducibility of layer of IrSi3 in contact with Si. Also serves as barrier to chemical reactions between Ir overlayer and Si substrate. Detectors used to form focal-plane array integrated with charge-coupled-device-addressing and image-processing circuitry.

  6. OH reaction rate constant, IR absorption spectrum, ozone depletion potentials and global warming potentials of 2-bromo-3,3,3-trifluoropropene

    NASA Astrophysics Data System (ADS)

    Patten, Kenneth O.; Khamaganov, Victor G.; Orkin, Vladimir L.; Baughcum, Steven L.; Wuebbles, Donald J.

    2011-12-01

    The rate constant for the gas phase reaction of OH radicals with BTP (2-bromo-3,3,3-trifluoropropene, CH2 = CBrCF3) was measured using a flash photolysis resonance-fluorescence technique over the temperature range 220 K to 370 K. The Arrhenius plot was found to exhibit noticeable curvature. The temperature dependence of the rate constant can be represented askBTP(220 - 370 K) = 4.85 × 10-13 × (T/298)0.92 × exp{+613/T} cm3 molecule-1 s-1. For atmospheric modeling purposes, kBTP(T) can be equally well represented by the standard Arrhenius expression kBTP(220 - 298 K) = 1.05 × 10-12 × exp{+381/T} cm3 molecule-1 s-1. The IR absorption cross-sections of BTP were also measured between 450 cm-1 and 1900 cm-1. BTP atmospheric lifetime, Ozone Depletion Potential (ODP), and Global Warming Potential (GWP) were evaluated in the Whole Atmosphere Community Climate Model for land emissions from 30 to 60°N and from 60°S to 60°N. The global, annual average atmospheric lifetime of BTP in the former scenario was 7.0 days, its ODP was 0.0028, and its GWP (100-yr time horizon) was 0.0050; in the latter scenario, the global, annual average BTP lifetime was 4.3 days, ODP was 0.0052, and 100-yr GWP was 0.0028. The short lifetime, low ODP, and low GWP indicate that BTP should have minimal effects on ozone and climate. Little BTP reaches the stratosphere in either emission scenario, but 27% of the ozone loss in the 30 to 60°N scenario and 46% of the ozone loss in the 60°S to 60°N scenario occurs above the tropopause due to Bry from BTP.

  7. Multinuclear Solid-State NMR Studies of Polymers and Immobilized Sonogashira Catalysts for Cross-Coupling Reactions

    E-print Network

    Pope, Jacqueline Christine

    2014-08-28

    °C (ca. 600 °F). Interactions and reactions of H2O with the functional groups of the polymers are studied using D2O in combination with IR, 2H MAS, and 1H wideline solid-state NMR. Three different processes taking place during high-temperature steam...

  8. Organo-niobate Ionic Liquids: Synthesis, Characterization and Application as Acid Catalyst in Pechmann Reactions

    PubMed Central

    Soares, Valerio C. D.; Alves, Melquizedeque B.; Souza, Ernesto R.; Pinto, Ivana O.; Rubim, Joel C.; Andrade, Carlos Kleber Z.; Suarez, Paulo A. Z.

    2007-01-01

    The combinations of 1-butyl-3-methylimidazolium chloride with NbCl5 yielded ionic mixtures with different melting point temperatures and acidity depending on the niobium molar fraction. The mixtures were characterized by thermal (DSC) and spectroscopic (FT-IR and 1H NMR) analysis. The Pechmann reactions of different phenols with ethylacetoacetate, producing coumarins, was used as model to evaluate the catalytic behavior of these mixtures as acid Lewis catalyst. These reactions were carried out using acidic mixtures of 60 mol%.

  9. Synthesis of highly active superacids of SO 4 \\/ZrO 2 with Ir, Pt, Rh, Ru, Os, and Pd substances for reaction of butane

    Microsoft Academic Search

    Makoto Hino; Kazushi Arata

    1994-01-01

    Highly acidic catalysts stronger than the SO4\\/ZrO2 superacid with an acid strength of Ho ? -16.04 were obtained by kneading Zr(OH)4 with ammonium sulfate together with chlorides of Ir, Pt, Rh, Ru, Os, and Pd followed by calcining in air at 600°C, the metal concentration being equivalent to Pt of 7.5 wt% based on the hydroxide. The catalysts with Ir

  10. Human Resource (HR) Implications of IV Monoclonal Antibody (MoAb) Infusion Reactions (IR): Data from a Time and Motion Study

    Microsoft Academic Search

    B. V. F ORTNER; E. J. S TEP; M. S. W ALKER; R ESEARCH N ETWORK

    2007-01-01

    expanding area of oncology therapeutics. ? MoAbs have generally fewer side effects and different toxicity profiles than cytotoxic chemotherapy. ? However, IRs may occur with IV administration of MoAb therapy. • Although most patients receive pre-medications as prophylaxis, the rate of IRs for cetuximab is 15% in head and neck cancer, 19-21% in metatstatic colorectal cancer, and for rituximab 77%

  11. U1h shaft project

    SciTech Connect

    Brian Briggs; R. G. Musick

    2000-06-30

    The U1h shaft project is a design/build subcontract to construct one 20 foot (ft) finished diameter shaft to a depth of 1,045 ft at the Nevada Test Site. Atkinson Construction was subcontracted by Bechtel Nevada to construct the U1h Shaft for the Department of Energy. The project consists of furnishing and installing the sinking plant, construction of the 1,045 ft of concrete lined shaft, development of a shaft station at a depth of 976 ft, and construction of a loading pocket at the station. The outfitting of the shaft and installation of a new hoist may be incorporated into the project at a later date. This paper should be of interest to those involved with the construction of relatively deep shafts and underground excavations.

  12. Charged pion form factor between Q{sup 2}=0.60 and 2.45 GeV{sup 2}. I. Measurements of the cross section for the {sup 1}H(e,e{sup '}{pi}{sup +})n reaction

    SciTech Connect

    Blok, H. P. [Dept. of Physics, VU university, NL-1081 HV Amsterdam (Netherlands); NIKHEF, Postbus 41882, NL-1009 DB Amsterdam (Netherlands); Horn, T. [University of Maryland, College Park, Maryland 20742 (United States); Physics Division, TJNAF, Newport News, Virginia 23606 (United States); Huber, G. M.; Brash, E. J.; Kovaltchouk, V.; Lolos, G. J.; Meer, R. L. J. van der; Vidakovic, S.; Xu, C. [University of Regina, Regina, Saskatchewan S4S 0A2 (Canada); Beise, E. J.; Breuer, H.; Chang, C. C.; Chant, N.; Gustafsson, K.; King, P. M.; Liu, J.; Roos, P. G. [University of Maryland, College Park, Maryland 20742 (United States); Gaskell, D.; Mack, D. J.; Abbott, D. [Physics Division, TJNAF, Newport News, Virginia 23606 (United States)] (and others)

    2008-10-15

    Cross sections for the reaction {sup 1}H(e,e{sup '}{pi}{sup +})n were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using the high-intensity Continuous Electron Beam Accelerator Facility (CEBAF) to determine the charged pion form factor. Data were taken for central four-momentum transfers ranging from Q{sup 2}=0.60 to 2.45 GeV{sup 2} at an invariant mass of the virtual photon-nucleon system of W=1.95 and 2.22 GeV. The measured cross sections were separated into the four structure functions {sigma}{sub L},{sigma}{sub T},{sigma}{sub LT}, and {sigma}{sub TT}. The various parts of the experimental setup and the analysis steps are described in detail, including the calibrations and systematic studies, which were needed to obtain high-precision results. The different types of systematic uncertainties are also discussed. The results for the separated cross sections as a function of the Mandelstam variable t at the different values of Q{sup 2} are presented. Some global features of the data are discussed, and the data are compared with the results of some model calculations for the reaction {sup 1}H(e,e{sup '}{pi}{sup +})n.

  13. Structural studies of 1-phenyl-2,3-dimethyl-5-oxo-1,2-dihydro-1H-pyrazol-4-ammonium 2[(2-carboxyphenyl) disulfanyl]benzoate

    NASA Astrophysics Data System (ADS)

    Fazil, Shiji; Ravindran, Reena; Sarau Devi, A.; Bijili, B. K.

    2012-08-01

    Reaction of 4-aminoantipyrine with 2-mercaptobenzoic acid afforded a proton transfer derivative, 1-phenyl-2,3-dimethyl-5-oxo-1,2-dihydro-1H-pyrazol-4-ammonium 2[(2-carboxyphenyl) disulfanyl]benzoate, (HAAP+?HTBA-), via the oxidation of 2-mercaptobenzoic acid into 2,2'-dithiobis(benzoic acid). The compound has been characterized on the basis of elemental analysis, IR, 1H and 13C NMR and mass spectral data. The infrared spectrum suggests the existence of an ion-pair compound, which is further established by the single crystal X-ray analysis to be an extended 1D supramolecular chain network extending along 'b' cell direction. The compound shows good thermal stability.

  14. Measurement of the Two-Halo Neutron Transfer Reaction {sup 1}H({sup 11}Li,{sup 9}Li){sup 3}H at 3A MeV

    SciTech Connect

    Tanihata, I.; Alcorta, M.; Bandyopadhyay, D.; Bieri, R.; Buchmann, L.; Davids, B.; Galinski, N.; Howell, D.; Mills, W.; Mythili, S.; Openshaw, R.; Padilla-Rodal, E.; Ruprecht, G.; Sheffer, G.; Shotter, A. C.; Trinczek, M.; Walden, P.; Savajols, H.; Roger, T.; Caamano, M. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); GANIL, Bd Henri Becquerel, BP 55027, 14076 Caen Cedex 05 (France); Saint Mary's University, 923 Robie St., Halifax, Nova Scotia B3H 3C3 (Canada); ANL, 9700 S. Cass Ave., Argonne, Illinois 60439 (United States); LLNL, L-414, P.O. Box 808, Livermore, California 94551 (United States)] (and others)

    2008-05-16

    The p({sup 11}Li,{sup 9}Li)t reaction has been studied for the first time at an incident energy of 3A MeV at the new ISAC-2 facility at TRIUMF. An active target detector MAYA, built at GANIL, was used for the measurement. The differential cross sections have been determined for transitions to the {sup 9}Li ground and first excited states in a wide range of scattering angles. Multistep transfer calculations using different {sup 11}Li model wave functions show that wave functions with strong correlations between the halo neutrons are the most successful in reproducing the observation.

  15. Towards high-level theoretical studies of large biodiesel molecules: an ONIOM [QCISD(T)/CBS:DFT] study of hydrogen abstraction reactions of C(n)H(2n+1)COOC(m)H(2m+1) + H.

    PubMed

    Zhang, Lidong; Zhang, Peng

    2015-01-01

    Recent interest in biodiesel combustion urges the need for the theoretical chemical kinetics of large alkyl ester molecules. This is, however, computationally challenging for prevalent high-level electronic structure theory based methods. The hydrogen abstraction reactions of alky esters CnH2n+1COOCmH2m+1 (n = 1-5, 9, 15; m = 1, 2) by a hydrogen radical were investigated by a computational technique based on a two-layer ONIOM method, employing a QCISD(T)/CBS method for the high layer and a DFT method for the low layer. The calculated energy barriers and heats of reaction, using the ONIOM method with a minimum of the required chemically active portion, are in very good agreement with those obtained using the widely accepted high-level QCISD(T)/CBS theory because the computational errors were less than 0.1 kcal mol(-1) for all the tested cases. The ONIOM[QCISD(T)/CBS:DFT] method provides a computationally accurate and affordable approach to the high-level theoretical chemical kinetics of large biodiesel molecules. PMID:25382675

  16. IRS organigram

    NASA Technical Reports Server (NTRS)

    Messerschmid, Ernst

    1991-01-01

    Charts and graphs relative to magnetoplasmadynamic (MPD) thruster technology are given. The research activities at the Institute of Space Transportation, University of Stuttgart, are summarized. Information is given on the Institute's Electric Propulsion and Plasma Wind Tunnel; thermal arcjet research; the nozzle-type thruster, DT-IRS; nozzle-type MPD thrusters; a hot anode thruster; the DT6 thruster; the ZT-1 thruster; the cylindrical MPD thruster; and a comparison of continuous and quasi-steady MPD.

  17. Determination of the Rate Constants for the NH2(X(2)B1) + NH2(X(2)B1) and NH2(X(2)B1) + H Recombination Reactions in N2 as a Function of Temperature and Pressure.

    PubMed

    Altinay, Gokhan; Macdonald, R Glen

    2015-07-16

    The recombination rate constants for the reactions NH2 + NH2 ? N2H4 (reaction k1b) and NH2 + H ? NH3 (reaction k2b) with N2 as a third-body have been measured as a function of temperature and pressure. The temperature range was from 292 to 533 K and the pressure range from a few Torr up to 300-400 Torr, well within the pressure falloff region. The NH2 radical was produced by 193 nm pulsed-laser photolysis of NH3 in a temperature controlled flow chamber. High-resolution time-resolved laser absorption spectroscopy was used to follow the temporal concentration profiles of both NH2 and NH3, simultaneously. The NH2 radical was monitored at 14800.65 cm(-1) using the (1)231 (0,7,0)Ã(2)A1 ? (1)331 (0,0,0)X?(2)B1 ro-vibronic transition, and NH3 monitored at 3336.39 cm(-1) on the (q)Q3(3)s (1,0,0,0) ? (0,0,0,0) ro-vibrational transition. The necessary collisional broadening parameters for each molecule were measured in separate experiments. The pressure and temperature dependence of k1b can be represented by the Troe parameters: k0, the low-pressure three-body recombination rate constant, k0(T) = (1.14 ± 0.59) × 10(-19)T(-(3.41±0.28)) cm(6) molecule(-2) s(-1), and Fcent, the pressure broadening parameter, Fcent = 0.15 ± 0.12, independent of temperature. The data could not be fit by three-independent parameters, and the high-pressure limiting rate constant k?(T) = 9.33 × 10(-10)T(-0.414) e(33/T) cm(3) molecule(-1) s(-1) was taken from the high-quality theoretical calculations of Klippenstein et al. (J. Phys. Chem A 2009, 113, 10241). The pressure and temperature dependence of k2b, can be represented by the Troe parameters: k0(T) = (9.95 ± 0.58) × 10(-26)T((-1.76±0.092)) cm(6) molecule(-2) s(-1), Fcent = 0.5 ± 0.2, k? = 2.6 × 10(-10) cm(3) molecule(-1) s(-1). Again, the data could not be fit with three independent parameters, and k2b? was chosen to be 2.6 × 10(-10) cm(3) molecule(-1) s(-1) and fixed in the analysis. PMID:25871301

  18. Synthesis, characterization and theoretical studies of 5-(benzylthio)-1-cylopentyl-1H-tetrazole

    NASA Astrophysics Data System (ADS)

    Saglam, S.; Disli, A.; Erdogdu, Y.; Marchewka, M. K.; Kanagathara, N.; Bay, B.; Güllüo?lu, M. T.

    2015-01-01

    In this study, 5-(benzylthio)-1-cylopentyl-1H-tetrazole (5B1C1HT) have been synthesized. Boiling points of the obtained compound have been determined and it has been characterized by FT-IR, 1H NMR, 13C-APT and LC-MS spectroscopy techniques. The FT-IR, 1H NMR and 13C-APT spectral measurements of the 5B1C1HT compound and complete assignment of the vibrational bands observed in spectra has been discussed. The spectra were interpreted with the aid of normal coordinate analysis following full structure optimization and force field calculations based on Density Functional Theory (DFT) at 6-311++G**, cc-pVDZ and cc-pVTZ basis sets. The optimized geometry with 6-311++G** basis sets were used to determine the total energy distribution, harmonic vibrational frequencies, IR intensities.

  19. CP-MAS 13C NMR and FT-IR investigation of the degradation reactions of polymer constituents in wood welding

    Microsoft Academic Search

    L. Delmotte; C. Ganne-Chedeville; J. M. Leban; A. Pizzi; F. Pichelin

    2008-01-01

    The essential chemical modifications involving the polymeric constituents of wood in friction welding occur in the first 5–6s slowing down or even stopping afterwards. FT-IR and CP-MAS 13C NMR of the welded area of wood have shown dehydration and an apparent increase in the crystallinity of cellulose. A certain level of hemicelluloses degradation occurs, accompanied by the generation of some

  20. Improved homopolymer separation to enable the application of 1H NMR and HPLC for the determination of the reaction parameters of the graft copolymerization of acrylic acid onto starch.

    PubMed

    Witono, Judy R; Marsman, Jan Henk; Noordergraaf, Inge-Willem; Heeres, Hero J; Janssen, Leon P B M

    2013-04-01

    Graft copolymers of starch with acrylic acid are a promising green, bio based material with many potential applications. The grafting of acrylic acid onto cassava starch in an aqueous medium initiated by Fenton's reagent has been studied. Common grafting result parameters are add-on (yield) and graft efficiency (selectivity). However, the analysis of the reaction products and an accurate determination of these parameters stand or fall with a complete separation of the entangled but ungrafted homopolymer from the grafted product. Therefore, this separation is the core of the newly developed analytical procedure. An appropriate solvent has been selected with dedicated testing from the range methanol, ethanol, acetone, dioxane, 2-propanol, and 1-propanol. Acetone showed the best performance in many respects. It has a high dissolving power for the homopolymer, as well as the highest yield of precipitation for the starch derivatives and it is the most economical in use. After the successful separation, the precipitated graft copolymers could be analyzed quantitatively by nuclear magnetic resonance. The liquid with homopolymer and unreacted monomer was analyzed by high pressure liquid chromatography. Proof of grafting has been found by FTIR and TGA analyses. The mass balance calculation shows a systematic error which appears fairly consistent: 18.0±2.5 wt%. This was used as a correction factor in the calculation of the grafting parameters but more importantly, it means that the method we developed has a high level of repeatability, in the order of 97%. PMID:23435285

  1. Measurements of the neutron electric to magnetic form factor ratio G{sub En}/G{sub Mn} via the {sup 2}H(e{yields},e{sup '}n{yields}){sup 1}H reaction to Q{sup 2}=1.45 (GeV/c){sup 2}

    SciTech Connect

    Plaster, B. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); California Institute of Technology, Pasadena, California 91125 (United States); Semenov, A.Yu.; Semenova, I.A. [Kent State University, Kent, Ohio 44242 (United States); Joint Institute for Nuclear Research, Dubna RU-141980 (Russian Federation); Aghalaryan, A.; Asaturyan, R.; Mkrtchyan, H.; Stepanyan, S.; Tadevosyan, V. [Yerevan Physics Institute, Yerevan 375036 (Armenia); Crouse, E.; Finn, J.M.; Perdrisat, C.; Roche, J. [College of William and Mary, Williamsburg, Virginia 23187 (United States); MacLachlan, G.; Opper, A.K. [Ohio University, Athens, Ohio 45701 (United States); Tajima, S.; Churchwell, S.; Howell, C.R. [Duke University and TUNL, Durham, North Carolina 27708 (United States); Tireman, W. [Kent State University, Kent, Ohio 44242 (United States); Northern Michigan University, Marquette, Michigan 49855 (United States); Ahmidouch, A. [North Carolina A and T State University, Greensboro, North Carolina 27411 (United States); Anderson, B. D. [Kent State University, Kent, Ohio 44242 (United States)] (and others)

    2006-02-15

    We report values for the neutron electric to magnetic form factor ratio, G{sub En}/G{sub Mn}, deduced from measurements of the neutron's recoil polarization in the quasielastic {sup 2}H(e{yields},e{sup '}n{yields}){sup 1}H reaction, at three Q{sup 2} values of 0.45, 1.13, and 1.45 (GeV/c){sup 2}. The data at Q{sup 2}=1.13 and 1.45 (GeV/c){sup 2} are the first direct experimental measurements of G{sub En} employing polarization degrees of freedom in the Q{sup 2}>1 (GeV/c){sup 2} region and stand as the most precise determinations of G{sub En} for all values of Q{sup 2}.

  2. Formation of complex defects involving molecular oxygen by electron-hole reactions in x-irradiated KClO4 and KBrO4, studied by ESR and IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Bjerre, Nis; Byberg, J. R.

    1985-03-01

    Complex defects of composition [XO-2, O2], X=Cl, Br, produced by UV or x-irradiation of solid KClO4 and KBrO4 at 26 K are characterized by ESR and IR spectroscopy. [XO-2, O2] is shown to arise during x-irradiation in a reaction between self-trapped electrons in the form of XO2-4 defects, and self-trapped holes in the form of (XO4)-2 defects. The previously described hole defect [XO2, O2] is shown to arise from oxidation of [XO-2, O2] by reaction with (XO4)-2. Thus all the abundant defects observed in x-irradiated KClO4 and KBrO4 stem from self-trapping of electrons and holes and from simple reactions of the self-trapped electrons and holes. The observed equivalence of optical excitation of the anions with electron-hole recombination may be a general property of polyatomic solids.

  3. FT-IR, FT-Raman, molecular structure, first order hyperpolarizability, HOMO and LUMO analysis, MEP and NBO analysis of 3-(adamantan-1-yl)-4-(prop-2-en-1-yl)-1H-1,2,4-triazole-5(4H)-thione, a potential bioactive agent.

    PubMed

    Rosline Sebastian, S H; Attia, Mohamed I; Almutairi, Maha S; El-Emam, Ali A; Panicker, C Yohannan; Van Alsenoy, Christian

    2014-11-11

    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 3-(adamantan-1-yl)-4-(prop-2-en-1-yl)-1H-1,2,4-triazole-5(4H)-thione have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of normal modes vibrations was done using GAR2PED program. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. The stability of the molecule arising from hyperconjugative interaction and charge delocalization has been analyzed using NBO analysis. The calculated geometrical parameters are in agreement with the XRD data. The calculated first hyperpolarizability is high and the title compound is an attractive candidate for further studies in nonlinear optical applications. To estimate the chemical reactivity of the molecule, the molecular electrostatic potential is calculated for the optimized geometry of the molecule. PMID:24878436

  4. In situ time-resolved diffraction coupled with a thermal I.R. camera to study mechanically activated SHS reaction: Case of Fe-Al binary system

    SciTech Connect

    Charlot, F. [CNRS, Dijon (France). Lab. de Recherches sur la Reactivite des Solides] [CNRS, Dijon (France). Lab. de Recherches sur la Reactivite des Solides; [UPR CNRS, Belfort (France); Bernard, F.; Niepce, J.C. [CNRS, Dijon (France). Lab. de Recherches sur la Reactivite des Solides] [CNRS, Dijon (France). Lab. de Recherches sur la Reactivite des Solides; Gaffet, E. [UPR CNRS, Belfort (France)] [UPR CNRS, Belfort (France); Klein, D. [LMIT Pole Univ. Belfort-Montbeliard, Montbeliard (France)] [LMIT Pole Univ. Belfort-Montbeliard, Montbeliard (France)

    1999-01-15

    Mechanically activated self-propagating high-temperature synthesis (MASHS) provides an attractive practical alternative to the conventional methods of producing intermetallic compounds, such as iron aluminides. This process involves mainly the combination of two steps; the first step, a mechanical activation, where pure elemental (Fe + Al) powders were co-milled inside a planetary mill, for a short time at given frequency and energy shocks and, the second step, a self-propagating high-temperature synthesis (SHS) reaction, which uses the exothermicity of the Fe + Al reaction. Once ignited with an external source, these reactions become self-sustained and propagate to completion within seconds. The combustion front directly leads to the formation of a nanometric Fe-Al intermetallic with a relative density of 70--80%. To understand this self-sustained reaction, an in situ study in real time was investigated on samples which differ by the shock power during milling and the compaction pressure (porosity). When the combustion front goes through the sample, the time-resolved X-ray diffraction experiment (TRXRD) using synchrotron radiation coupled with an infrared thermography allows the in situ study of the phase formation and the temperature evolution during the MASHs process.

  5. IR Spectra of Isocyanic Acid (HNCO) and its Reaction Product with Ammonia: Possible Identification of the 4.6 and 6.8 Micron Absorption Features of Several Protostellar Objects

    NASA Astrophysics Data System (ADS)

    Lowenthal, M. S.; Khanna, R. K.; Moore, M. H.

    2000-10-01

    Strong absorption features are found at 4.6 microns (2170 cm-1) and 6.8 microns (1470 cm-1) in the spectra of several protostellar objects (e.g. W33A, NGC 7538 IRS9, RAFGL 7009S). Ices with similar features may have been present in the early solar system. Realistic candidates responsible for the 6.8 micron band include CH3OH, and/or ions such as CO3=, HCO3-, and NH4+. The 4.6 micron feature is due to the absorption of the cyanate ion (OCN-). We have synthesized and obtained the infrared spectrum of pure, solid HNCO and measured its intrinsic band strength. We have also investigated the IR spectrum of HNCO covered with a layer of H2O and NH3 at low temperatures ( 10K). During warm-up to 100K, an acid-base reaction occurs and new peaks develop around 1470 cm-1 and 2170 cm-1 which are due to NH4+ and OCN- ions, respectively. Irradiation of solid HNCO shows evidence of OCN- formation at low temperatures. The conditions under which NH4OCN converts into urea ((NH2)2CO) will be discussed. Ammonium cyanate is a good candidate for the source of the 4.6 and 6.8 micron interstellar features and may also exist in cometary ices.

  6. A validated 1H NMR method for the determination of the degree of deacetylation of chitosan

    Microsoft Academic Search

    M. Lavertu; Z. Xia; A. N. Serreqi; M. Berrada; A. Rodrigues; D. Wang; M. D. Buschmann; Ajay Gupta

    2003-01-01

    A method for the determination of the degree of deacetylation (DDA) of chitosan by 1H NMR spectroscopy has been formally validated. Chitosans with DDA ranging from 48 to 100% have been used for the validation. The method is found to be simple, rapid and more precise than other known techniques like IR or titration for %DDA measurements. The precision, ruggedness,

  7. Global sampling of the photochemical reaction paths of bromoform by ultrafast deep-UV through near-IR transient absorption and ab initio multiconfigurational calculations.

    PubMed

    Pal, S K; Mereshchenko, A S; Butaeva, E V; El-Khoury, P Z; Tarnovsky, A N

    2013-03-28

    Ultrafast deep-ultraviolet through near infrared (210-950 nm) transient absorption spectroscopy complemented by ab initio multiconfigurational calculations offers a global description of the photochemical reaction pathways of bromoform following 255-nm excitation in methylcyclohexane and acetonitrile solutions. Photoexcitation of CHBr3 leads to the ground-state iso-CHBr3 product in a large quantum yield (?35%), formed through two different mechanisms: concerted excited-state isomerization and cage-induced isomerization through the recombination of the nascent radical pair. These two processes take place on different time scales of tens of femtoseconds and several picoseconds, respectively. The novel ultrafast direct isomerization pathway proposed herein is consistent with the occurrence of a conical intersection between the first excited singlet state of CHBr3 and the ground electronic state of iso-CHBr3. Complete active space self-consistent field calculations characterize this singularity in the vicinity of a second order saddle point on the ground state which connects the two isomer forms. For cage-induced isomerization, both the formation of the nascent radical pair and its subsequent collapse into ground-state iso-CHBr3 are directly monitored through the deep-ultraviolet absorption signatures of the radical species. In both mechanisms, the optically active (i.e., those with largest Franck-Condon factors) C-Br-Br bending and Br-Br stretching modes of ground-state iso-CHBr3 have the largest projection on the reaction coordinate, enabling us to trace the structural changes accompanying vibrational relaxation of the non-equilibrated isomers through transient absorption dynamics. The iso-CHBr3 photoproduct is stable in methylcyclohexane, but undergoes either facile thermal isomerization to the parent CHBr3 structure through a cyclic transition state stabilized by the polar acetonitrile medium (?300-ps lifetime), and hydrolysis in the presence of water. PMID:23556730

  8. 1H-detected 1H- 1H correlation spectroscopy of a stereo-array isotope labeled amino acid under fast magic-angle spinning

    NASA Astrophysics Data System (ADS)

    Takahashi, Hiroki; Kainosho, Masatsune; Akutsu, Hideo; Fujiwara, Toshimichi

    2010-04-01

    The combined use of selective deuteration, stereo-array isotope labeling (SAIL), and fast magic-angle spinning effectively suppresses the 1H- 1H dipolar couplings in organic solids. This method provided the high-field 1H NMR linewidths comparable to those achieved by combined rotation and multiple-pulse spectroscopy. This technique was applied to two-dimensional 1H-detected 1H- 1H polarization transfer CHH experiments of valine. The signal sensitivity for the 1H-detected CHH experiments was greater than that for the 13C-detected 1H- 1H polarization transfer experiments by a factor of 2-4. We obtained the 1H- 1H distances in SAIL valine by CHH experiments with an accuracy of about 0.2 Å by using a theory developed for 1H- 1H polarization transfer in 13C-labeled organic compounds.

  9. Level scheme of 194Ir

    NASA Astrophysics Data System (ADS)

    Balodis, M.; Prokofjevs, P.; Kr? Mere, N.; Simonova, L.; B? Rzinš , J.; Krasta, T.; Kern, J.; Raemy, A.; Dousse, J. C.; Schwitz, W.; Cizewski, J. A.; Colvin, G. G.; Boerner, H. G.; Geltenbort, P.; Hoyler, F.; Kerr, S. A.; Schreckenbach, K.; Georgii, R.; von Egidy, T.; Klora, J.; Lindner, H.; Mayerhofer, U.; Walter, A.; Murzin, A. V.; Libman, V. A.; Kondurov, I. A.; Loginov, Yu. E.; Sushkov, P. A.; Brant, S.; Paar, V.; Lopac, V.

    1998-10-01

    Levels of 194Ir were studied using neutron capture and ( d, p) reaction spectroscopy. A pair spectrometer was used to measure the high-energy ?-ray spectrum from thermal-neutron capture in an enriched 193Ir target over the energy range 4640-6100 keV. From the same reaction, low-energy ?-radiation was studied using curved-crystal spectrometers, and conversion electrons were observed with magnetic spectrometers. Prompt and delayed ??-coincidences were measured using semiconductor and scintillation detectors. Averaged resonance capture measurements were performed with 2 keV and 24 keV neutrons for primary transitions leading to excitation energies from 0 to 580 keV. Using 22 MeV deuterons, the 193Ir( d, p) high resolution spectra were observed with a magnetic spectrograph. The deduced nuclear level scheme of 194Ir includes 38 levels connected by 184 transitions. Unambiguous spins and parities were determined for 25 levels. The rotor-plus-particle model was used for the interpretation of the level scheme assuming a strong mixing for Nilsson configurations having identical parities and K quantum numbers. IBFFM model calculations were performed and the obtained results were compared with the experimental level scheme.

  10. Synthesis, spectroscopic and theoretical studies of ethyl (2E)-3-amino-2-({[(4-benzoyl-1,5-diphenyl-1H-pyrazol-3-yl)carbonyl]amino}carbonothioyl)but-2-enoate butanol solvate

    NASA Astrophysics Data System (ADS)

    Koca, ?rfan; Sert, Yusuf; Gümü?, Mehmet; Kani, ?brahim; Ç?rak, Ça?r?

    2014-01-01

    We have synthesized ethyl (2E)-3-amino-2-({[(4-benzoyl-1,5-diphenyl-1H-pyrazol-3-yl)carbonyl]amino}carbonothioyl)but-2-enoate (2) by the reaction of 4-benzoyl-1,5-diphenyl-1H-pyrazole-3-carbonyl chloride (1), ammonium thiocyanate and ethyl 3-aminobut-2-enoate and then characterized by elemental analyses, IR, Raman, 1H NMR, 13C NMR and X-ray diffraction methods. The experimental and theoretical vibrational spectra of 2 were investigated. The experimental FT-IR (4000-400 cm-1) and Laser-Raman spectra (4000-100 cm-1) of the molecule in the solid phase were recorded. Theoretical vibrational frequencies and geometric parameters (bond lengths, bond angles) were calculated using Ab Initio Hartree Fock (HF), Density Functional Theory (B3LYP) methods with 6-311++G(d,p) basis set by Gaussian 09W program. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. The assignments of the vibrational frequencies were performed by potential energy distribution (PED) analysis by using VEDA 4 program. The theoretical optimized geometric parameters and vibrational frequencies were compared with the corresponding experimental X-ray diffraction data, and they were seen to be in a good agreement with each other. Also, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies were calculated.

  11. Catalytic Activity of Platinum Monolayer on Iridium and Rhenium Alloy Nanoparticles for the Oxygen Reduction Reaction

    SciTech Connect

    Karan, Hiroko I.; Sasaki, Kotaro; Kuttiyiel, Kurian; Farberow, Carrie A.; Mavrikakis, Manos; Adzic, Radoslav R.

    2012-05-04

    A new type of electrocatalyst with a core?shell structure that consists of a platinum monolayer shell placed on an iridium? rhenium nanoparticle core or platinum and palladium bilayer shell deposited on that core has been prepared and tested for electrocatalytic activity for the oxygen reduction reaction. Carbon-supported iridium? rhenium alloy nanoparticles with several different molar ratios of Ir to Re were prepared by reducing metal chlorides dispersed on Vulcan carbon with hydrogen gas at 400 °C for 1 h. These catalysts showed specific electrocatalytic activity for oxygen reduction reaction comparable to that of platinum. The activities of PtML/PdML/Ir2Re1, PtML/Pd2layers/Ir2Re1, and PtML/Pd2layers/Ir7Re3 catalysts were, in fact, better than that of conventional platinum electrocatalysts, and their mass activities exceeded the 2015 DOE target. Our density functional theory calculations revealed that the molar ratio of Ir to Re affects the binding strength of adsorbed OH and, thereby, the O2 reduction activity of the catalysts. The maximum specific activity was found for an intermediate OH binding energy with the corresponding catalyst on the top of the volcano plot. The monolayer concept facilitates the use of much less platinum than in other approaches. The results with the PtML/PdML/Ir2Re electrocatalyst indicate that it is a promising alternative to conventional Pt electrocatalysts in low-temperature fuel cells.

  12. Synthesis and structural characterization of 1,2-bis((1 H-pyrrol-2-yl)methylene)hydrazine and its Cu(II) complex

    NASA Astrophysics Data System (ADS)

    Zhang, Guoqi; Yang, Lanying; Ma, Jinshi; Yang, Guoqiang

    2011-12-01

    The hydrogen-bonding potential and complexation behavior with copper(II) of a multidentate Schiff-base ligand, 1,2-bis((1 H-pyrrol-2-yl)methylene)hydrazine (H 2L) was studied. Crystallization of H 2L from an aqueous methanol solution resulted in the formation of an adduct H 2L·H 2O, which features a two-dimensional (2D) supramolecular hydrogen-bonded network, as evidenced by X-ray structural analysis. The reaction of H 2L with copper(II) salt in a CH 2Cl 2sbnd MeOH solution formed a dinuclear double-stranded helicate, Cu 2( L) 2 ( 1) in high yield, which was characterized by microanalysis, IR spectra, and single-crystal X-ray crystallographic analysis. UV-vis titration experiments confirmed the spontaneous formation of a 1:1 metal-ligand complex in solution.

  13. Characterisation of the 1H and 13C NMR spectra of methylcitric acid

    NASA Astrophysics Data System (ADS)

    Krawczyk, Hanna; Martyniuk, Tomasz

    2007-06-01

    Methylcitric acid (MCA) was synthesised in Reformatsky reaction (2 RS, 3 RS stereoisomers) and in the nucleophilic addition (2 RS, 3 SR stereoisomers). The stereoselectivity of these reactions was analysed. 1H and 13C NMR spectra of diastereoisomers of methylcitric acid were recorded and interpreted. The values of 1H chemical shifts and 1H- 1H coupling constants were analysed. Proton-decoupled high-resolution 13C NMR spectra of MCA diastereoisomers were measured in a series of dilute water solutions of various acidities. These data may provide a basis for unequivocal determination of the presence of MCA in the urine samples of patients' suffering from propionic acidemia, methylmalonic aciduria, or holocarboxylase synthetase deficiency. NMR spectroscopy enables determination of MCA diastereoisomers in body fluids and can be a complementary and useful diagnostic tool.

  14. Conversion factors for carbohydrate analysis by hydrolysis and 1 H-NMR spectroscopy

    Microsoft Academic Search

    Soo-Jeong Shin; Nam-Seok Cho

    2008-01-01

    Conversion factor to calibrate the lower xylan content in carbohydrate compositional analysis in wood by 1H-NMR spectroscopy was investigated. During acid hydrolysis, xylan monomer was dehydrated as furfural, and that furfural was\\u000a further degraded or condensed in acidic reaction condition. Anomeric hydrogen peaks integration in 1H-NMR spectroscopic method excluded xylose reacted products (such as furfural and their condensed or degraded

  15. ALBERMARLE PAMLICO IR 2002

    EPA Science Inventory

    The 2002 Albermarle Pamlico Implementation Review (IR) highlights recent successes and challenges with the estuary program. Various components within the IR include: CCMP implementation, outlining priority management actions, public involvement, stakeholder contribution, and limi...

  16. Enhanced Y1H Assays for Arabidopis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transcription regulation plays a key role in development and response to environment. To understand this mechanism, we need to know which transcription factor (TFs) would bind to which promoter, thus regulate their target gene expression. Yeast one-hybrid (Y1H) technique can be used to map this kind...

  17. 1H Cramps Based on Trev

    NASA Astrophysics Data System (ADS)

    Buszko, M. L.; Bronnimann, C. E.; Maciel, G. E.

    Line-narrowing effects of the 1H TREV-8 pulse sequence applied to solids rotating at the magic angle have been examined. Polycrystalline samples of adipic, malonic, and fumaric acids, adamantane, a barley seed, and a pyridine-saturated coal sample were examined. The TREV-based 1H CRAMPS technique is seen to provide reasonably effective line narrowing for both "soft" solids (adamantane) and rigid solids (carboxylic acids), enabling 1H chemical-shift fine structure to be observed. For adamantane, the 1H linewidth is reduced from about 13 kHz (static) to 40 Hz (CRAMPS) at a 840 Hz MAS rate and a pulse spacing (?) of 7.8 ?s. The line-narrowing efficiency increases for larger ? values, but does not approach the efficiency of BR-24. However, unlike the case for BR-24 or other multiple-pulse line-narrowing sequences based on the formation of solid echoes, the line-narrowing efficiency of TREV-8 is sustained for large offsets; this feature, along with a relatively large bandwidth, may be an important factor when the sequence is implemented in 19F CRAMPS and in solid-sample imaging studies. TREV-CRAMPS may also be useful for samples in which the somewhat inferior line-narrowing behavior may be masked by line-broadening effects not based on homonuclear dipolar interactions.

  18. Intrinsic excitations in 192Ir

    NASA Astrophysics Data System (ADS)

    Kern, Jean; Balodis, M. K.; Beer, W.; Brandt, S.; Casten, R. F.; Chalupka, A.; Coveca, C.; Dousse, J.-Cl.; Eder, R.; von Egidy, T.; Gardner, D. G.; Gardner, M. A.; Giaacobbe, P.; Gill, R. L.; Hagn, E.; Hoff, R. W.; Hungerford, M. A.; Kondurov, I. A.; Kononenko, I. V.; Kramer, N. D.; Libman, V. A.; Loginov, Yu. E.; Murzin, A. V.; Paar, V.; Prokofjev, P. T.; Raemy, A.; Scheerer, H. J.; Schmidt, H. H.; Schwitz, W.; Simonova, L. I.; Sushkov, P. A.; Zech, E.

    1991-10-01

    The structure of the odd-odd 192Ir nucleus presents an interesting and challenging problem for both experimentalists and theorists. As a result of the common efforts of nine laboratories, it is possible, for the first time, to propose an extended scheme with 34 levels. The experiments included observation of ?-ray transitions and of conversion electrons emitted after thermal and resonance neutron capture, of direct (d,p) and (d,t) neutron transfer reactions and of the angular distribution of ?-rays from aligned 192Ir nuclei. The results are interpreted in the framework of the rotor-plus-particle and IBFFM models. The nuclear states appear to be strongly mixed. The complex and interesting ground-state configuration is discussed.

  19. 1H–NMR Metabolomic Biomarkers of Poor Outcome after Hemorrhagic Shock are Absent in Hibernators

    PubMed Central

    Bogren, Lori K.; Murphy, Carl J.; Johnston, Erin L.; Sinha, Neeraj; Serkova, Natalie J.; Drew, Kelly L.

    2014-01-01

    Background Hemorrhagic shock (HS) following trauma is a leading cause of death among persons under the age of 40. During HS the body undergoes systemic warm ischemia followed by reperfusion during medical intervention. Ischemia/reperfusion (I/R) results in a disruption of cellular metabolic processes that ultimately lead to tissue and organ dysfunction or failure. Resistance to I/R injury is a characteristic of hibernating mammals. The present study sought to identify circulating metabolites in the rat as biomarkers for metabolic alterations associated with poor outcome after HS. Arctic ground squirrels (AGS), a hibernating species that resists I/R injury independent of decreased body temperature (warm I/R), was used as a negative control. Methodology/principal findings Male Sprague-Dawley rats and AGS were subject to HS by withdrawing blood to a mean arterial pressure (MAP) of 35 mmHg and maintaining the low MAP for 20 min before reperfusing with Ringers. The animals’ temperature was maintained at 37±0.5°C for the duration of the experiment. Plasma samples were taken immediately before hemorrhage and three hours after reperfusion. Hydrophilic and lipid metabolites from plasma were then analyzed via 1H–NMR from unprocessed plasma and lipid extracts, respectively. Rats, susceptible to I/R injury, had a qualitative shift in their hydrophilic metabolic fingerprint including differential activation of glucose and anaerobic metabolism and had alterations in several metabolites during I/R indicative of metabolic adjustments and organ damage. In contrast, I/R injury resistant AGS, regardless of season or body temperature, maintained a stable metabolic homeostasis revealed by a qualitative 1H–NMR metabolic profile with few changes in quantified metabolites during HS-induced global I/R. Conclusions/significance An increase in circulating metabolites indicative of anaerobic metabolism and activation of glycolytic pathways is associated with poor prognosis after HS in rats. These same biomarkers are absent in AGS after HS with warm I/R. PMID:25211248

  20. Microcavity array IR photodetector

    Microsoft Academic Search

    A K Esman; V K Kuleshov; G L Zykov

    2009-01-01

    An original microcavity array IR photodetector is proposed and the sensitivity and response time of its pixels are calculated. A photosensitive element represents a composite silicon microcavity made of two optically coupled closed waveguides on a dielectric substrate whose resonance wave depends on its temperature. This dependence is used to detect IR radiation which heats an absorbing element and the

  1. IrO2-deposited Pt electrocatalysts for unitized regenerative polymer electrolyte fuel cells

    Microsoft Academic Search

    T. Ioroi; N. Kitazawa; K. Yasuda; Y. Yamamoto; H. Takenaka

    2001-01-01

    An IrO2\\/Pt electrocatalyst for the polymer electrolyte-type unitized regenerative fuel cell (URFC) was prepared by deposition of iridium oxide (IrO2) particles on Pt black via a colloidal iridium hydroxide hydrate precursor, and URFC performance was examined. After the iridium hydroxide hydrate deposited Pt was calcined at 400 °C in air for 1 h, rutile-structure IrO2 particles (20–50 nm dia.) were

  2. IR Hot Wave

    SciTech Connect

    Graham, T. B.

    2010-04-01

    The IR Hot Wave{trademark} furnace is a breakthrough heat treatment system for manufacturing metal components. Near-infrared (IR) radiant energy combines with IR convective heating for heat treating. Heat treatment is an essential process in the manufacture of most components. The controlled heating and cooling of a metal or metal alloy alters its physical, mechanical, and sometimes chemical properties without changing the object's shape. The IR Hot Wave{trademark} furnace offers the simplest, quickest, most efficient, and cost-effective heat treatment option for metals and metal alloys. Compared with other heat treatment alternatives, the IR Hot Wave{trademark} system: (1) is 3 to 15 times faster; (2) is 2 to 3 times more energy efficient; (3) is 20% to 50% more cost-effective; (4) has a {+-}1 C thermal profile compared to a {+-}10 C thermal profile for conventional gas furnaces; and (5) has a 25% to 50% smaller footprint.

  3. Reaction of the biheteroaromatic ligand 2-(2?-pyridyl)quinoxaline (L) were zinc(II) and cadmium(II) halides: Preparation and characterization of the 1 : 1 complexes

    Microsoft Academic Search

    Nick Hadjiliadis

    1995-01-01

    The reactions of ZnX2 and CdX2 (X = Cl, Br, I) with the biheteroaromatic ligand 2-(2?-pyridyl)quinoxaline (L) were studied in ethanolic solutions. The new complexes [ZnX2L] (X = Cl, Br, I), [CdI2L] and [Cd2X4L2] were isolated and characterized by elemental analyses, conductivity measurements, X-ray powder patterns, thermal methods (TG\\/DTG, DTA) and spectroscopic (IR, far-IR, Raman, 1H NMR) studies. The X-ray

  4. Observation of 1H-13C and 1H-1H proximities in a paramagnetic solid by NMR at high magnetic field under ultra-fast MAS.

    PubMed

    Li, Shenhui; Trébosc, Julien; Lafon, Olivier; Zhou, Lei; Shen, Ming; Pourpoint, Frédérique; Amoureux, Jean-Paul; Deng, Feng

    2015-02-01

    The assignment of NMR signals in paramagnetic solids is often challenging since: (i) the large paramagnetic shifts often mask the diamagnetic shifts specific to the local chemical environment, and (ii) the hyperfine interactions with unpaired electrons broaden the NMR spectra and decrease the coherence lifetime, thus reducing the efficiency of usual homo- and hetero-nuclear NMR correlation experiments. Here we show that the assignment of (1)H and (13)C signals in isotopically unmodified paramagnetic compounds with moderate hyperfine interactions can be facilitated by the use of two two-dimensional (2D) experiments: (i) (1)H-(13)C correlations with (1)H detection and (ii) (1)H-(1)H double-quantum?single-quantum correlations. These methods are experimentally demonstrated on isotopically unmodified copper (II) complex of l-alanine at high magnetic field (18.8 T) and ultra-fast Magic Angle Spinning (MAS) frequency of 62.5 kHz. Compared to (13)C detection, we show that (1)H detection leads to a 3-fold enhancement in sensitivity for (1)H-(13)C 2D correlation experiments. By combining (1)H-(13)C and (1)H-(1)H 2D correlation experiments with the analysis of (13)C longitudinal relaxation times, we have been able to assign the (1)H and (13)C signals of each l-alanine ligand. PMID:25557861

  5. Synthesis and Supramolecular Structure of a (5-(3-(1H-tetrazol-5-yl)phenyl)-1H-tetrazole) Cobalt Complex

    PubMed Central

    Kostakis, George E.; Anson, Christopher E.; Powell, Annie K.

    2010-01-01

    The reaction of CoCl2·6H2O with m-BDTH2 (1,3-benzeneditetrazol-5-yl) leads to [Co(C8H6N8)2(H2O)2(CH3CN)2]Cl2 (1). Both tetrazolic groups remain protonated existing in a 1H tautomeric form. A trifurcated chlorine atom and stacking interactions assemble compound 1 into a three-dimensional network. PMID:20631832

  6. 1H MR SPECTROSCOPY IN COMMON DEMENTIAS

    PubMed Central

    Kantarci, Kejal; Petersen, Ronald C.; Boeve, Bradley F.; Knopman, David S.; Tang-Wai, David F.; O'Brien, Peter C.; Weigand, Stephen D.; Edland, Steven D.; Smith, Glenn E.; Ivnik, Robert J.; Ferman, Tanis J.; Tangalos, Eric G.; Jack, Clifford R.

    2009-01-01

    Objective To determine the 1H MR spectroscopic (MRS) findings and inter-group differences among common dementias: Alzheimer's disease (AD), vascular dementia (VaD), dementia with Lewy bodies (DLB), and frontotemporal lobar degeneration (FTLD). Methods We consecutively recruited 206 normal elderly, 121 patients with AD, 41 with FTLD, 20 with DLB, and 8 with VaD. We evaluated the 1H MRS metabolite ratio changes in common dementias with respect to normal, and also differences among the common dementias. Results N-acetylaspartate/Creatine (NAA/Cr) was lower than normal in patients with AD, FTLD, and VaD. Myo-inositol (mI)/Cr was higher than normal in patients with AD and FTLD. Choline (Cho)/Cr was higher than normal in patients with, AD, FTLD, and DLB. There were no metabolite differences between patients with AD and FTLD, nor between patients with DLB and VaD. NAA /Cr was lower in patients with AD and FTLD than DLB. MI /Cr was higher in patients with AD and FTLD than VaD. MI /Cr was also higher in patients with FTLD than DLB. Conclusions NAA/Cr levels are decreased in dementias that are characterized by neuron loss such as AD, FTLD, and VaD. MI/Cr levels are elevated in dementias that are pathologically characterized by gliosis such as AD and FTLD. Cho/Cr levels are elevated in dementias that are characterized by a profound cholinergic deficit such as AD and DLB. PMID:15505154

  7. IR in Norway

    NASA Astrophysics Data System (ADS)

    Haakenaasen, Randi; Lovold, Stian

    2003-01-01

    Infrared technology in Norway started at the Norwegian Defense Research Establishment (FFI) in the 1960s, and has since then spread to universities, other research institutes and industry. FFI has a large, integrated IR activity that includes research and development in IR detectors, optics design, optical coatings, advanced dewar design, modelling/simulation of IR scenes, and image analysis. Part of the integrated activity is a laboratory for more basic research in materials science and semiconductor physics, in which thin films of CdHgTe are grown by molecular beam epitaxy and processed into IR detectors by various techniques. FFI also has a lot of experience in research and development of tunable infrared lasers for various applications. Norwegian industrial activities include production of infrared homing anti-ship missiles, laser rangefinders, various infrared gas sensors, hyperspectral cameras, and fiberoptic sensor systems for structural health monitoring and offshore oil well diagnostics.

  8. Synthesis of 1H-indole-2,3-dione-3-thiosemicarbazone ribonucleosides as antibacterial agents.

    PubMed

    Kassab, Shaymaa E; Hegazy, Gehan H; Eid, Nahed M; Amin, Kamelia M; El-Gendy, Adel A

    2010-01-01

    A new isatin ribonucleoside (3) was synthesized in a good yield by trimethylsilyl trifluoromethanesulfonate (TMSOTf) catalyzed coupling reaction between the silylated nitrogenated base of 1H-Indole-2,3-dione (1) and 1,2,3,5-tetra-O-acetyl-beta-D-ribfuranose (2). Thiosemicarbazides 4a-e were utilized by the prepared ribonucleoside (3) to give new series of 1H-indole-2,3-dione-3-thiosemicarbazone ribonucleosides 5a-e. All compounds tested as antibacterial agents showed slight inhibitory activity against the selected bacterial strains. PMID:20391194

  9. CCD and IR array controllers

    Microsoft Academic Search

    Robert W. Leach; Frank J. Low

    2000-01-01

    A family of controllers has bene developed that is powerful and flexible enough to operate a wide range of CCD and IR focal plane arrays in a variety of ground-based applications. These include fast readout of small CCD and IR arrays for adaptive optics applications, slow readout of large CCD and IR mosaics, and single CCD and IR array operation

  10. A study on the thermal decomposition behavior of derivatives of 1,5-diamino-1 H-tetrazole (DAT): A new family of energetic heterocyclic-based salts

    Microsoft Academic Search

    Gerd Fischer; Gerhard Holl; Thomas M. Klapötke; Jan J. Weigand

    2005-01-01

    The thermal decomposition of the highly energetic 1,5-diamino-4-methyl-1H-tetrazolium nitrate (2b), 1,5-diamino-4-methyl-1H-tetrazolium dinitramide (2c) and 1,5-diamino-4-methyl-1H-tetrazolium azide (2d) were investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Mass spectrometry and IR spectroscopy were used to identify the gaseous products. Decomposition appears in the cases of 2c and 2d to be initiated by a proton transfer to form the corresponding

  11. Microcavity array IR photodetector

    SciTech Connect

    Esman, A K; Kuleshov, V K; Zykov, G L [B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk (Belarus)

    2009-12-31

    An original microcavity array IR photodetector is proposed and the sensitivity and response time of its pixels are calculated. A photosensitive element represents a composite silicon microcavity made of two optically coupled closed waveguides on a dielectric substrate whose resonance wave depends on its temperature. This dependence is used to detect IR radiation which heats an absorbing element and the composite microcavity thermally coupled with this element. It is shown that for a spatial resolution of 45 {mu}m, the time response is 30 ms and the sensitivity is 10{sup -3} K at the IR radiation power of {approx} 4.7 x 10{sup -8} W element{sup -1}. (photodetectors)

  12. Practical choice of 1H- 1H decoupling schemes in through-bond 1H-{X} HMQC experiments at ultra-fast MAS

    NASA Astrophysics Data System (ADS)

    Nishiyama, Yusuke; Lu, Xingyu; Trébosc, Julien; Lafon, Olivier; Gan, Zhehong; Madhu, P. K.; Amoureux, Jean-Paul

    2012-01-01

    Three 1H- 1H homonuclear dipolar decoupling schemes for 1H indirect detection measurements at very fast MAS are compared. The sequences require the following conditions: (i) being operable at very fast MAS, (ii) a long T2' value, (iii) a large scaling factor, (iv) a small number of adjustable parameters, (v) an acquisition window, (vi) a low rf-power requirement, and (vii) a z-rotation feature. To satisfy these conditions a modified sequence named TIlted Magic-Echo Sandwich with zero degree sandwich pulse (TIMES 0) is introduced. The basic elements of TIMES 0 consist of one sampling window and two phase-ramped irradiations, which realize alternating positive and negative 360° rotations of 1H magnetization around an effective field tilted with an angle ? from the B0 axis. The TIMES 0 sequence benefits from very large chemical shift scaling factors at ultra-fast MAS that reach ?cs = 0.90 for ? = 25° at ?r = 80 kHz MAS and only four adjustable parameters, resulting in easy setup. Long ?T2' values, where T2' is a irreversible proton transverse relaxation time, greatly enhance the sensitivity in 1H-{ 13C} through-bond J-HMQC (Heteronuclear Multiple-Quantum Coherence) measurements with 1H- 1H decoupling during magnetization transfer periods. Although similar sensitivity can be obtained with through-space D-HMQC sequences, in which 13C- 1H dipolar interactions are recoupled, J-HMQC experiments incorporating 1H- 1H decoupling benefit from lower t1-noise, more uniform excitation of both CH, CH 2 and CH 3 moieties, and easier identification of through-bond connectivities.

  13. Characterization of sacha inchi ( Plukenetia volubilis L.) oil by FTIR spectroscopy and 1 H NMR. Comparison with linseed oil

    Microsoft Academic Search

    María D. Guillén; Ainhoa Ruiz; Nerea Cabo; Rosana Chirinos; Gloria Pascual

    2003-01-01

    Three oil samples obtained from sacha inchi (Plukenetia volubilis L.) seeds were studied by means of FTIR and 1H NMR. Frequency data of the most significant bands of the IR spectrum of this oil are given. These data show that sacha inchi\\u000a oil has a high degree of unsaturation. The same fact is deduced from the ratio between the absorbance

  14. Polymer monitoring with mid-IR fibers

    NASA Astrophysics Data System (ADS)

    de Haseth, James A.

    1993-12-01

    Polymeric materials, specifically polyurethanes, have been investigated with the use of mid- infrared transmitting fibers. The fibers are used as internal reflection elements for attenuated total reflectance (ATR) spectrometry. Fourier transform infrared (FT-IR) spectrometers were used to collect the data. Spectra were collected at rates of three spectra per second to 5 seconds per spectrum. The spectral bandpass of the systems was from approximately 5500 cm-1 to 850 cm-1. Not only was the reaction chemistry monitored, but chemical morphological changes were recorded as well. Water slabstock polyurethane foams were studied as were reaction injection molded (RIM) polyurethanes.

  15. Synthesis, spectroscopic characterization, calculational studies and in vitro antitumoral activity of 4-(3-(1H-imidazol-1-yl)propyl)-(thiophen-2-ylmethyl)-1H-1,2,4-triazol-5(4H)-one

    NASA Astrophysics Data System (ADS)

    Süleymano?lu, Nevin; Ustaba?, Re?at; Alpaslan, Yelda Bingöl; Ünver, Yasemin; Turan, Mustafa; Sancak, Kemal

    2011-03-01

    4-(3-(1H-imidazol-1-yl)propyl)-(thiophen-2-ylmethyl)-1H-1,2,4-triazol-5(4H)-one (IPTT), C 13H 15N 5OS, was synthesized and characterized by 13C NMR, 1H NMR, IR and single-crystal X-ray diffraction. The structure of IPTT is stabilized by three intermolecular hydrogen bonds and by intermolecular C sbnd H⋯ ? interaction. The compound IPTT was modelled by using DFT method. Calculations of vibrational frequencies, gauge including atomic orbital (GIAO), 1H and 13C NMR chemical shifts of IPTT in the ground state, total electronic charge density map and frontier molecular orbitals were performed at B3LYP/6-31 G(d) level of theory were carried out by using DFT method with 6-31 G(d) basis set. The structural parameters obtained by geometry optimization, the theoretical vibrational frequencies and chemical shift values are in good agreement with experimental ones. FT-IR, NMR and X-ray analytical results of IPTT show that the compound exists as keto form, that was supported by DFT calculations. In addition, in vitro studies showed hopeful antitumoral activity of the title IPTT compound.

  16. IRS1/A0484

    NSDL National Science Digital Library

    2009-04-14

    The insulin receptor substrate 1 (IRS1, also known as A0484) is a docking and adaptor protein that is multiply phosphorylated by a variety of protein kinases and is the major substrate of the insulin and insulin-like growth factor receptors (IGFRs).

  17. Airborne IR surveys

    Microsoft Academic Search

    Link; L. E. Jr

    1978-01-01

    Energy conservation has become an important consideration in facilities management at military installations. Implementing effective conservation measures is complicated by the geographic extent and diversity of facilities. One problem is identifying sources of excessive energy consumption so that corrective measures can be taken. Recent studies at the Army Engineer Waterways Experiment Station have shown that thermal infrared (IR) imaging systems

  18. IR gain monitor

    NASA Astrophysics Data System (ADS)

    Hilbert, Bryan

    2013-10-01

    The gain of the IR channel of WFC3 will be measured using a series of internal flat fields. Using knowledge gained from ground testing and previous cycles, we propose to collect flat field ramps which will be used to create photon transfer curves and give a measure of the gain. This continues the strategy of last cycle's gain monitor, in proposal 13080.

  19. ?-Oxido-bis­[hydridotris(tri­methyl­phosphane-?P)iridium(III)](Ir—Ir) bis­(tetra­fluorido­borate) dihydrate

    PubMed Central

    Merola, Joseph; Husebo, Trang Le

    2014-01-01

    The title compound, [Ir2H2O(C3H9P)6](BF4)2·2H2O, was isolated from the reaction between [Ir(COD)(PMe3)3]BF4 and H2 in water (COD is cyclo­octa-1,5-diene). The asymmetric unit consists of one IrIII atom bonded to three PMe3 groups, one hydride ligand and half an oxide ligand, in addition to a BF4 ? counter-ion and one water molecule of hydration. The single oxide ligand bridging two IrIII atoms is disordered across an inversion center with each O atom having a 50% site occupancy. Each IrIII atom has three PMe3 groups occupying facial positions, with the half-occupancy O atoms, a hydride ligand and an Ir—Ir bond completing the coordination sphere. The Ir—Ir distance is 2.8614?(12)?Å, comparable to other iridium(III) metal–metal bonds. Two water mol­ecules hydrogen bond to two BF4 ? anions in the unit cell. PMID:24826089

  20. Synthesis of 3-(1-Methyl-1H-imidazol-2-ylthio)propanoic Acid and (E)-3-(1-Methyl-1H-imidazol-2-ylthio)acrylic Acid.

    PubMed

    Hattan, Christopher M; Shojaie, Jalil; Lau, Serrine S; Anders, M W

    2013-01-01

    The syntheses of 3-(1-methyl-1H-imidazol-2-ylthio)acrylic acid and 3-(1-methyl-1H-imidazol-2-ylthio)propanoic acid, mitochondria-targeted prodrugs of the antioxidant methimazole, are described. The method of Fan et al. (Fan et al., Synthesis 2006, 2286) for the reaction of phenols with propiolic acid and propiolate esters was modified to synthesize (E)-3-(1-methyl-1H-imidazol-2-ylthio)acrylic acid. The intermediate tert-butyl (E)-3-(1-methyl-1H-imidazol-2-ylthio)acrylate was prepared by the reaction of tert-butyl propiolate with methimazole; the use of tert-butyl propiolate rather than methyl propiolate gave tert-butyl (E)-3-(1-methyl-1H-imidazol-2-ylthio)acrylate as the predominant isomer. Acid hydrolysis of the intermediate ester afforded the target compound. 3-(1-Methyl-1H-imidazol-2-ylthio)propanoic acid was synthesized from 3-bromopropanoic acid and methimazole under conditions that gave preferential substitution on sulfur and minimized substitution on nitrogen. PMID:24882887

  1. 17O, 1H coupling constants in intramolecular hydrogen bonds

    NASA Astrophysics Data System (ADS)

    Bolkunov, I. A.; Sergeyev, N. M.; Shapet'ko, N. N.

    1990-11-01

    17O, 1H spin-spin coupling constants in systems with intramolecular hydrogen bonds are reported. The 17O NMR spectra, proton decoupling and the special DECOMPOSITION program were used. In asymmetrical systems, 17O, 1H coupling constants of about 80 Hz were found for one of the oxygen nuclei while for symmetrical systems 17O, 1H coupling constants of about 30 Hz were observed for both equivalent oxygen nuclei. The data on 17O, 1H coupling constants can be used to estimate the state of the proton in the hydrogen bond.

  2. Chlorination of (Phebox)Ir(mesityl)(OAc) by Thionyl Chloride.

    PubMed

    Zhou, Meng; Goldman, Alan S

    2015-01-01

    Pincer (Phebox)Ir(mesityl)(OAc) (2) (Phebox = 3,5-dimethylphenyl-2,6-bis(oxazolinyl)) complex, formed by benzylic C-H activation of mesitylene (1,3,5-trimethylbenzene) using (Phebox)Ir(OAc)2OH2 (1), was treated with thionyl chloride to rapidly form 1-(chloromethyl)-3,5-dimethylbenzene in 50% yield at 23 °C. A green species was obtained at the end of reaction, which decomposed during flash column chromatography to form (Phebox)IrCl2OH2 in 87% yield. PMID:26039335

  3. Cryostat attachment for IR spectrometers

    Microsoft Academic Search

    A. N. Ternovoi; B. Z. Belashev

    1989-01-01

    UDC 535.853 Devices for controlling the temperature are employed in IR spectroscopy in order to obtain spectra of materials at low and medium temperatures. The geometry of the optical system of such devices is traditional and corresponds to recording IR transmission spectra. In many cases the information obtained from IR transmission spectra is inadequate. For example, for strongly absorbing materials

  4. Measurement of 1H-15N and 1H-13C residual dipolar couplings in nucleic acids from TROSY intensities

    PubMed Central

    Ying, Jinfa; Wang, Jinbu; Grishaev, Alex; Yu, Ping; Wang, Yun-Xing; Bax, Ad

    2011-01-01

    Analogous to the recently introduced ARTSY method for measurement of one-bond 1H-15N residual dipolar couplings (RDCs) in large perdeuterated proteins, we introduce methods for measurement of base 13C-1H and 15N-1H RDCs in protonated nucleic acids. Measurements are based on quantitative analysis of intensities in 1H-15N and 13C-1H TROSY-HSQC spectra, and are illustrated for a 71-nucleotide adenine riboswitch. Results compare favorably with those of conventional frequency-based measurements in terms of completeness and convenience of use. The ARTSY method derives the size of the coupling from the ratio of intensities observed in two TROSY-HSQC spectra recorded with different dephasing delays, thereby minimizing potential resonance overlap problems. Precision of the RDC measurements is limited by the signal-to-noise ratio, S/N, achievable in the 2D TROSY-HSQC reference spectrum, and is approximately given by 30/(S/N) Hz for 15N-1H and 65/(S/N) Hz for 13C-1H. The signal-to-noise ratio of both 1H-15N and 1H-13C spectra greatly benefits when water magnetization during the experiments is not perturbed, such that rapid magnetization transfer from bulk water to the nucleic acid, mediated by rapid amino and hydroxyl hydrogen exchange coupled with 1H-1H NOE transfer, allows for fast repetition of the experiment. RDCs in the mutated helix 1 of the riboswitch are compatible with nucleotide-specifically modeled, idealized A-form geometry and a static orientation relative to the helix 2/3 pair, which differs by ca 6° relative to the X-ray structure of the native riboswitch. PMID:21947918

  5. Template-free synthesis of AlPO 4-H1, -H2, and -H3 by microwave heating

    Microsoft Academic Search

    Katsuyuki Kunii; Kazuhiro Narahara; Shoji Yamanaka

    2002-01-01

    Aluminophosphate molecular sieves (AlPO4's) were prepared by microwave heating without using organic template reagents. The microwave heating enhanced the crystallization of aluminophosphate gels, and AlPO4-H1, -H2(AHT), and -H3(APC) were successfully obtained as single phases in a relatively short reaction time. The reaction conditions used for the crystallization of the three kinds of AlPO4's were very similar to each other, but

  6. One-pot synthesis of 3,4-dihydropyrimidin-2(1 H)-ones using boric acid as catalyst

    Microsoft Academic Search

    Shujang Tu; Fang Fang; Chunbao Miao; Hong Jiang; Youjian Feng; Daqing Shi; Xiangshan Wang

    2003-01-01

    A simple effective synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives, using boric acid as catalyst, from aromatic aldehydes, 1,3-dicarbonyl compounds and urea in glacial acetic acid is described. Compared with the classical Biginelli reaction conditions, this new method has the advantage of excellent yields (86–97%) and short reaction time (0.5–2 h).

  7. Novel 1H low field nuclear magnetic resonance applications for the field of biodiesel

    PubMed Central

    2013-01-01

    Background Biodiesel production has increased dramatically over the last decade, raising the need for new rapid and non-destructive analytical tools and technologies. 1H Low Field Nuclear Magnetic Resonance (LF-NMR) applications, which offer great potential to the field of biodiesel, have been developed by the Phyto Lipid Biotechnology Lab research team in the last few years. Results Supervised and un-supervised chemometric tools are suggested for screening new alternative biodiesel feedstocks according to oil content and viscosity. The tools allowed assignment into viscosity groups of biodiesel-petrodiesel samples whose viscosity is unknown, and uncovered biodiesel samples that have residues of unreacted acylglycerol and/or methanol, and poorly separated and cleaned glycerol and water. In the case of composite materials, relaxation time distribution, and cross-correlation methods were successfully applied to differentiate components. Continuous distributed methods were also applied to calculate the yield of the transesterification reaction, and thus monitor the progress of the common and in-situ transesterification reactions, offering a tool for optimization of reaction parameters. Conclusions Comprehensive applied tools are detailed for the characterization of new alternative biodiesel resources in their whole conformation, monitoring of the biodiesel transesterification reaction, and quality evaluation of the final product, using a non-invasive and non-destructive technology that is new to the biodiesel research area. A new integrated computational-experimental approach for analysis of 1H LF-NMR relaxometry data is also presented, suggesting improved solution stability and peak resolution. PMID:23590829

  8. Theoretical Investigation of Iridium (II) Sulfides Ir2(?-S)2(PH3)4 AND Ir2(?-S)2(PPh3)4 

    E-print Network

    Kritikou, Stella

    2014-02-27

    Density functional theory results of the electronic structure of an iridium sulfide, Ir_(2)S_(2)(PPh_(3))_(4) (2), are presented here, along with a discussion of the reaction mechanism of dihydrogen activation on this sulfide. This Ir (II...

  9. Theoretical Investigation of Iridium (II) Sulfides Ir2(?-S)2(PH3)4 AND Ir2(?-S)2(PPh3)4

    E-print Network

    Kritikou, Stella

    2014-02-27

    Density functional theory results of the electronic structure of an iridium sulfide, Ir_(2)S_(2)(PPh_(3))_(4) (2), are presented here, along with a discussion of the reaction mechanism of dihydrogen activation on this sulfide. This Ir (II...

  10. A one-pot reaction to synthesize two types of fluorescent materials containing benzothiazolyl moiety

    NASA Astrophysics Data System (ADS)

    Yu, Tianzhi; Zhang, Chengcheng; Zhao, Yuling; Chai, Haifang; Fan, Duowang; Ma, Ying; Yao, Shanglei; Li, Wentao

    2013-05-01

    Two different types of fluorescent materials containing benzothiazolyl moiety, 2-(benzothiazol-2-yl)phenol derivatives and 3-(benzothiazol-2-yl)coumarin derivatives, were synthesized synchronously using ethyl cyanoacetate, appropriate aromatic aldehyde and 2-aminothiophenol as the starting materials under the catalysis of benzoic acid by one-pot reaction. This method has the advantages of mild reaction conditions, easy processing and low waste. All synthesized compounds were characterized by elemental analysis, IR, 1H NMR spectra. The structures of 2-(benzothiazol-2-yl)phenol derivatives, 2-(benzothiazol-2-yl)phenol (BTP) and 2-(benzothiazol-2-yl)naphthol (BTN), were determined by X-ray single crystal analysis. The UV-vis absorption and photoluminescence spectra of all synthesized compounds were investigated. The 2-(benzothiazol-2-yl)phenol derivatives exhibit bright green emissions and 3-(benzothiazol-2-yl)coumarin derivatives emit bright blue light in solutions.

  11. Towards the automatic analysis of NMR spectra: part 7. Assignment of 1H by employing both 1H and 1H/13C correlation spectra.

    PubMed

    Griffiths, Lee; Beeley, Howard H; Horton, Rob

    2008-09-01

    A reliable method of automatically assigning one-dimensional proton spectra is described. The method relies on the alignment of the proton spectrum with an associated heteronuclear single-quantum coherence (HSQC) spectrum, transferring the stoichiometry and couplings to the HSQC. The HSQC spectrum is then assigned using a linear assignment procedure in which a fitness function incorporating (1)H chemical shifts, (1)H couplings and (13)C shifts are employed. The method uniquely employs a sequential procedure in which only correlations of like stoichiometry are assigned at the same time. PMID:18561211

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

    PubMed

    Vignali, Carlo; Caligiani, Augusta; Palla, Gerardo

    2007-07-01

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

  13. 1 H NMR metabolic fingerprinting of saffron extracts

    Microsoft Academic Search

    Ali Yilmaz; Nils T. Nyberg; Per Mølgaard; Javad Asili; Jerzy W. Jaroszewski

    2010-01-01

    The aim of this study was to explore feasibility of 1H NMR metabolic fingerprinting for discrimination of authenticity of saffron using principal component analysis (PCA) modeling.\\u000a Authentic reference Iranian saffron (n = 31) and commercial samples (n = 32) were used. Cross-validated PCA models based on 1H NMR spectra of solutions prepared by direct extraction of grinded saffron with methanol-d\\u000a 4 distinguished reference Iranian

  14. Vibrational analyses of 1,3-dibenzoyl-4,5-dihydro-1H-imidazole-2-thione and 1,3-dibenzoyl tetrahydropyrimidine-2(1H)-thione by normal coordinate treatment

    NASA Astrophysics Data System (ADS)

    Gumus, Sedat; Sundius, Tom; Yilmaz, Veysel Turan

    2012-12-01

    Vibrational analyses of 1,3-dibenzoyl-4,5-dihydro-1H-imidazole-2-thione and 1,3-dibenzoyl tetrahydropyrimidine-2(1H)-thione were carried out using normal coordinate analysis. FT-IR spectra were recorded in the region 4000-400 cm-1. The harmonic vibrational frequencies, molecular geometry and atomic charges have been computed, and NBO analysis has been carried out with the help of B3LYP density functional theory (DFT). The computed geometrical bond lengths and bond angles agree well with the crystallographic data. Atomic charges based on Mulliken population analysis, natural population analysis, Hirshfeld-I analysis and CHelpG analysis were calculated using the basis sets of 6-31G? and 6-31G??. Stabilities of the two molecules were analyzed by means of natural bond orbital (NBO) analysis and delocalized ?-?? interactions.

  15. Vibrational analyses of 1,3-dibenzoyl-4,5-dihydro-1H-imidazole-2-thione and 1,3-dibenzoyl tetrahydropyrimidine-2(1H)-thione by normal coordinate treatment.

    PubMed

    Gumus, Sedat; Sundius, Tom; Yilmaz, Veysel Turan

    2012-12-01

    Vibrational analyses of 1,3-dibenzoyl-4,5-dihydro-1H-imidazole-2-thione and 1,3-dibenzoyl tetrahydropyrimidine-2(1H)-thione were carried out using normal coordinate analysis. FT-IR spectra were recorded in the region 4000-400 cm(-1). The harmonic vibrational frequencies, molecular geometry and atomic charges have been computed, and NBO analysis has been carried out with the help of B3LYP density functional theory (DFT). The computed geometrical bond lengths and bond angles agree well with the crystallographic data. Atomic charges based on Mulliken population analysis, natural population analysis, Hirshfeld-I analysis and CHelpG analysis were calculated using the basis sets of 6-31G(*) and 6-31G(**). Stabilities of the two molecules were analyzed by means of natural bond orbital (NBO) analysis and delocalized ?-?(*) interactions. PMID:22995469

  16. Integrated IR sensors

    NASA Astrophysics Data System (ADS)

    Tom, Michael; Trujillo, Edward

    1994-06-01

    Integrated infrared (IR) sensors which exploit modular avionics concepts can provide features such as operational flexibility, enhanced stealthiness, and ease of maintenance to meet the demands of tactical, airborne sensor systems. On-board, tactical airborne sensor systems perform target acquisition, tracking, identification, threat warning, missile launch detection, and ground mapping in support of situation awareness, self-defense, navigation, target attack, weapon support, and reconnaissance activities. The use of sensor suites for future tactical aircraft such as US Air Force's multirole fighter require a blend of sensor inputs and outputs that may vary over time. It is expected that special-role units of these tactical aircraft will be formed to conduct tasks and missions such as anti-shipping, reconnaissance, or suppression of enemy air defenses.

  17. IR Dark Monitor

    NASA Astrophysics Data System (ADS)

    Dulude, Michael

    2013-10-01

    Analysis of ground and on-orbit observations has shown that dark current is most effectively removed from external science images when using a composite dark calibration image created from a number of individual dark calibration images taken with the same sample sequence, exposure time, and aperture. Collection of dark calibration frames for all sample-sequence/aperture size combinations used by Cycle 21 IR-channel external observations is essential. They will be used to monitor variations in the dark current signal and will provide the input images necessary to generate timely, high-quality composite dark calibration frames which will be delivered to the calibration database system {CDBS} on an as-needed basis. In addition, some darks will also be used to monitor bad pixels and the long-term stability of the dark current, as well as trends in the zeroth read level, and bad pixels {hot, unstable, or dead}.

  18. Radicals and Hydroxy Radical Reactions in Troposphere

    E-print Network

    Schofield, Jeremy

    Radicals and Hydroxy Radical Reactions in Troposphere Examples of ground state radicals: 1. H atom: 1 electron 2. O and O 2 : unpaired electrons in orbitals: QM reason 3. OH: hydroxy radical: 7 valence electrons 4. OOH: peroxyl radical #15; Very reactive: 1 H#1; away from H 2 O, one electron away

  19. New insights into the solvent-assisted excited-state double proton transfer of 2-(1H-pyrazol-5-yl)pyridine with alcoholic partners: A TDDFT investigation

    NASA Astrophysics Data System (ADS)

    Li, Hui; Shi, Ying; Yin, Hang; Wang, Ye; Cong, Lin; Jin, Mingxing; Ding, Dajun

    2015-04-01

    Excited-state double proton transfer (ESDPT) in the hydrogen-bonded 2-(1H-pyrazol-5-yl)pyridine with propyl alcoholic partner (PPP) was theoretically investigated by time-dependent density functional theory (TDDFT) method. Great changes have taken place for the calculated geometric structures, the electron density features and vibrational spectrum of PPP system in S0 and S1 state. Our results have demonstrated that ESDPT reaction happens within the system upon photoexcitation. We also found that the ESDPT process is facilitated by the electronically excited state intermolecular hydrogen bond strengthening. Particularly, after the photoexcitation from HOMO(?) to the LUMO(??), the rearrangement of electronic density distribution of frontier molecular orbitals (MOs) on pyridine and the pyrazol moieties exhibits a very important positive factor for the ESDPT. Furthermore, by the investigation of the stretching vibrations of Nsbnd H and Osbnd H groups, the infrared (IR) spectroscopic results provide us not only a theoretical evidence of ESDPT, but also a considerable clue to characterize the nature of intermolecular reaction. In addition, efforts have also been devoted towards calculating the absorption peak, which shows good consistency with the experimental result of the studied system.

  20. Facile synthesis of 1-alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications.

    PubMed

    Lakshman, Mahesh K; Singh, Manish K; Kumar, Mukesh; Chamala, Raghu Ram; Yedulla, Vijayender R; Wagner, Domenick; Leung, Evan; Yang, Lijia; Matin, Asha; Ahmad, Sadia

    2014-01-01

    (1H-Benzo[d][1,2,3]triazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP), 1H-benzo[d][1,2,3]triazol-1-yl 4-methylbenzenesulfonate (Bt-OTs), and 3H-[1,2,3]triazolo[4,5-b]pyridine-3-yl 4-methylbenzenesulfonate (At-OTs) are classically utilized in peptide synthesis for amide-bond formation. However, a previously undescribed reaction of these compounds with alcohols in the presence of a base, leads to 1-alkoxy-1H-benzo- (Bt-OR) and 7-azabenzotriazoles (At-OR). Although BOP undergoes reactions with alcohols to furnish 1-alkoxy-1H-benzotriazoles, Bt-OTs proved to be superior. Both, primary and secondary alcohols undergo reaction under generally mild reaction conditions. Correspondingly, 1-alkoxy-1H-7-azabenzotriazoles were synthesized from At-OTs. Mechanistically, there are three pathways by which these peptide-coupling agents can react with alcohols. From (31)P{(1)H}, [(18)O]-labeling, and other chemical experiments, phosphonium and tosylate derivatives of alcohols seem to be intermediates. These then react with BtO(-) and AtO(-) produced in situ. In order to demonstrate broader utility, this novel reaction has been used to prepare a series of acyclic nucleoside-like compounds. Because BtO(-) is a nucleofuge, several Bt-OCH2Ar substrates have been evaluated in nucleophilic substitution reactions. Finally, the possible formation of Pd ?-allyl complexes by departure of BtO(-) has been queried. Thus, alpha-allylation of three cyclic ketones was evaluated with 1-(cinnamyloxy)-1H-benzo[d][1,2,3]triazole, via in situ formation of pyrrolidine enamines and Pd catalysis. PMID:25246951

  1. Facile synthesis of 1-alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications

    PubMed Central

    Singh, Manish K; Kumar, Mukesh; Chamala, Raghu Ram; Yedulla, Vijayender R; Wagner, Domenick; Leung, Evan; Yang, Lijia; Matin, Asha; Ahmad, Sadia

    2014-01-01

    Summary (1H-Benzo[d][1,2,3]triazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP), 1H-benzo[d][1,2,3]triazol-1-yl 4-methylbenzenesulfonate (Bt-OTs), and 3H-[1,2,3]triazolo[4,5-b]pyridine-3-yl 4-methylbenzenesulfonate (At-OTs) are classically utilized in peptide synthesis for amide-bond formation. However, a previously undescribed reaction of these compounds with alcohols in the presence of a base, leads to 1-alkoxy-1H-benzo- (Bt-OR) and 7-azabenzotriazoles (At-OR). Although BOP undergoes reactions with alcohols to furnish 1-alkoxy-1H-benzotriazoles, Bt-OTs proved to be superior. Both, primary and secondary alcohols undergo reaction under generally mild reaction conditions. Correspondingly, 1-alkoxy-1H-7-azabenzotriazoles were synthesized from At-OTs. Mechanistically, there are three pathways by which these peptide-coupling agents can react with alcohols. From 31P{1H}, [18O]-labeling, and other chemical experiments, phosphonium and tosylate derivatives of alcohols seem to be intermediates. These then react with BtO? and AtO? produced in situ. In order to demonstrate broader utility, this novel reaction has been used to prepare a series of acyclic nucleoside-like compounds. Because BtO? is a nucleofuge, several Bt-OCH2Ar substrates have been evaluated in nucleophilic substitution reactions. Finally, the possible formation of Pd ?–allyl complexes by departure of BtO? has been queried. Thus, alpha-allylation of three cyclic ketones was evaluated with 1-(cinnamyloxy)-1H-benzo[d][1,2,3]triazole, via in situ formation of pyrrolidine enamines and Pd catalysis. PMID:25246951

  2. Metabotyping of Long-Lived Mice using 1H NMR Spectroscopy

    PubMed Central

    2012-01-01

    Significant advances in understanding aging have been achieved through studying model organisms with extended healthy lifespans. Employing 1H NMR spectroscopy, we characterized the plasma metabolic phenotype (metabotype) of three long-lived murine models: 30% dietary restricted (DR), insulin receptor substrate 1 null (Irs1–/–), and Ames dwarf (Prop1df/df). A panel of metabolic differences were generated for each model relative to their controls, and subsequently, the three long-lived models were compared to one another. Concentrations of mobile very low density lipoproteins, trimethylamine, and choline were significantly decreased in the plasma of all three models. Metabolites including glucose, choline, glycerophosphocholine, and various lipids were significantly reduced, while acetoacetate, d-3-hydroxybutyrate and trimethylamine-N-oxide levels were increased in DR compared to ad libitum fed controls. Plasma lipids and glycerophosphocholine were also decreased in Irs1–/– mice compared to controls, as were methionine and citrate. In contrast, high density lipoproteins and glycerophosphocholine were increased in Ames dwarf mice, as were methionine and citrate. Pairwise comparisons indicated that differences existed between the metabotypes of the different long-lived mice models. Irs1–/– mice, for example, had elevated glucose, acetate, acetone, and creatine but lower methionine relative to DR mice and Ames dwarfs. Our study identified several potential candidate biomarkers directionally altered across all three models that may be predictive of longevity but also identified differences in the metabolic signatures. This comparative approach suggests that the metabolic networks underlying lifespan extension may not be exactly the same for each model of longevity and is consistent with multifactorial control of the aging process. PMID:22225495

  3. PHOTODETECTORS: Microcavity array IR photodetector

    Microsoft Academic Search

    A. K. Esman; V. K. Kuleshov; G. L. Zykov

    2009-01-01

    An original microcavity array IR photodetector is proposed and the sensitivity and response time of its pixels are calculated. A photosensitive element represents a composite silicon microcavity made of two optically coupled closed waveguides on a dielectric substrate whose resonance wave depends on its temperature. This dependence is used to detect IR radiation which heats an absorbing element and the

  4. Why current IR engines fail

    Microsoft Academic Search

    Chris Buckley

    2004-01-01

    Observations from a unique investigation of failure analysis of Information Retrieval (IR) research engines are presented. The Reliable Information Access (RIA) Workshop invited seven leading IR research groups to supply both their systems and their experts to an effort to analyze why their systems fail on some topics and whether the failures are due to system flaws, approach flaws, or

  5. Heteroepitaxial Ir layers on diamond

    NASA Astrophysics Data System (ADS)

    Martovitsky, V. P.; Evlashin, S. A.; Suetin, N. V.; Khmelnitsky, R. A.

    2011-06-01

    Ir layers were deposited on single-crystal diamond using magnetron sputtering at substrate temperatures ranging from 830 to 1150 °C. The grown films have high adhesion to diamond and a low surface roughness Rq = 4-6 nm according to the AFM measurements. Crystalline perfection of Ir layers was investigated using x-ray diffraction and heteroepitaxial growth of Ir on diamond was confirmed. Because the lattice parameters of Ir and diamond are significantly different (7.65%) and because the deposition temperature of Ir is low in comparison with its melting point (2443 °C), diffraction reflections of the films are similar to analogous reflections of diamond, but wider. The films consist of elongated crystallites of length 10-100 nm. By broadening the reciprocal lattice points, we conclude that the level of microstresses in the Ir films increases as the substrate temperature during deposition of Ir films on the (0 0 1) diamond substrate increases, and that the level of microstresses decreases for the films on the (0 1 1) substrate. Simultaneously, the misorientation of Ir crystallites on the (0 1 1) substrate also decreases with increasing temperature.

  6. The IR Theory Discussion List

    NSDL National Science Digital Library

    The Theory of International Relations List is a moderated, manually distributed list for the scholarly discussion of ideas and issues directly related to International Relations (IR) theory and its research, as well as communicating with others involved or interested in IR theory and its research.

  7. An in situ FT-IR study of CO hydrogenation over cerium oxide

    Microsoft Academic Search

    Kenichi Maruya; Takaharu Onishi; Kazunari Domen

    1993-01-01

    The CO hydrogenation over cerium oxide was studied by using a closed circulating reaction system and in situ Fourier transform infrared spectroscopy (FT-IR) at 300-673 K. The major products of the CO-H[sub 2] reaction over cerium oxide were found to be olefins (C[sub 2][sup =]-C[sub 4][sup =]), CH[sub 4], CO[sub 2], and H[sub 2]O. IR bands due to surface oxygen-containing

  8. FT-IR and Raman spectroscopic analysis of hydrated cesium borates and their saturated aqueous solution

    Microsoft Academic Search

    Liu Zhihong; Gao Bo; Hu Mancheng; Li Shuni; Xia Shuping

    2003-01-01

    Hydrated cesium borates have been synthesized by the reaction of Cs2CO3 with H3BO3 aqueous solution. After reaction equilibria were reached, liquid and solid phases were separated and the FT-IR difference and Raman spectra of each phase were recorded, respectively. The assignments of the recorded FT-IR absorption frequencies and Raman shift are given. The main polyborate anions and their interaction in

  9. Probing degradation in complex engineering silicones by 1H multiple quantum NMR

    SciTech Connect

    Maxwell, R S; Chinn, S C; Giuliani, J; Herberg, J L

    2007-09-05

    Static {sup 1}H Multiple Quantum Nuclear Magnetic Resonance (MQ NMR) has recently been shown to provide detailed insight into the network structure of pristine silicon based polymer systems. The MQ NMR method characterizes the residual dipolar couplings of the silicon chains that depend on the average molecular weight between physical or chemical constraints. Recently, we have employed MQ NMR methods to characterize the changes in network structure in a series of complex silicone materials subject to numerous degradation mechanisms, including thermal, radiative, and desiccative. For thermal degradation, MQ NMR shows that a combination of crosslinking due to post-curing reactions as well as random chain scissioning reactions occurs. For radiative degradation, the primary mechanisms are via crosslinking both in the network and at the interface between the polymer and the inorganic filler. For samples stored in highly desiccating environments, MQ NMR shows that the average segmental dynamics are slowed due to increased interactions between the filler and the network polymer chains.

  10. Ralf Siebenmorgen IR instrument from Antarctica (thermal) IR instruments from Antarctica

    E-print Network

    Siebenmorgen, Ralf

    Ralf Siebenmorgen IR instrument from Antarctica (thermal) IR instruments from Antarctica: what can Antarctica Atmospheric optical thickness spectrum #12;Ralf Siebenmorgen IR instrument from Antarctica Siebenmorgen IR instrument from Antarctica Paranal Dome C (30m) Atmospheric transmission #12;Ralf Siebenmorgen

  11. Metabolite Characterization in Peritoneal Dialysis Effluent Using High-resolution 1H and 1H-13C NMR Spectroscopy

    E-print Network

    Guleria, Anupam; Rawat, Atul; Khetrapal, C L; Prasad, Narayan; Kumar, Dinesh

    2014-01-01

    Metabolite analysis of peritoneal dialysis (PD) effluent may provide information regarding onset and progression of complications associated with prolonged PD therapy. In this context, the NMR detectable small metabolites of PD effluent samples were characterized using high resolution 1H and 1H-13C NMR spectroscopy. The various spectra were recorded (at 800 MHz proton frequency) on PD effluent samples obtained after 4 hour (intraperitoneal) dwell time from patients with end stage renal failure (ESRF) and continuing normally on PD therapy. Inspite of devastating spectral feature of PD effluent due to the presence of intense resonances from glucose and lactate, we were able to identify about 53 small endogenous metabolites (including many complex coupled spin systems) and more than 90 % of the total CH cross peaks of 1H-13C HSQC spectrum were identified specific to various metabolites of PD effluent. We foresee that the characteristic fingerprints of various metabolites of control PD effluent samples will be us...

  12. Le IR, c'est mort. Vive le IR

    E-print Network

    Salo, Dorothea

    2008-07-31

    The institutional repository is dead -- long live the institutional repository! Despite their rocky beginnings, IRs are finally finding their niche and surging forward. What were their initial mistakes, and how can further missteps be avoided? How...

  13. Diagnostic Performance 1 H after Simulation Training Predicts Learning

    ERIC Educational Resources Information Center

    Consoli, Anna; Fraser, Kristin; Ma, Irene; Sobczak, Matthew; Wright, Bruce; McLaughlin, Kevin

    2013-01-01

    Although simulation training improves post-training performance, it is unclear how well performance soon after simulation training predicts longer term outcomes (i.e., learning). Here our objective was to assess the predictive value of performance 1 h post-training of performance 6 weeks later. We trained 84 first year medical students a simulated…

  14. 1H NMR analysis of sporopollenin from Typha Angustifolia

    Microsoft Academic Search

    Friedhelm Ahlers; Ina Thom; Jörg Lambert; Rüdiger Kuckuk; Rolf Wiermann

    1999-01-01

    The first analysis of sporopollenin using 1H NMR-techniques revealed the presence of four phenolic compounds in different amounts. The phenolic compounds are tri- or tetrasubstituted. The sporopollenin was isolated and purified from Typha angustifolia by an enzymatic procedure, followed by extraction with organic solvents.

  15. Complete 1H and 13C spectral assignment of floridoside.

    PubMed

    Simon-Colin, Christelle; Kervarec, Nelly; Pichon, Roger; Deslandes, Eric

    2002-02-11

    Floridoside (2-O-alpha-D-galactopyranosylglycerol) was extracted from the red marine alga Rhodymenia palmata, and purified by ion-exchange chromatography: 1D and 2D NMR spectroscopy experiments were used to unambiguously assign the complete 1H and 13C spectra. PMID:11844498

  16. 2,2-Bis(hy­droxy­meth­yl)-2,3-dihydro-1H-pyrrolizin-1-one

    PubMed Central

    Ali, Yousuf; Peng, Yu; Hua, Erbing; Afza, Nighat; Khan, Rashid Ali

    2010-01-01

    The title compound, C9H11NO3, was prepared by an Aldol reaction of 2,3-dihydro-1H-pyrrolizin-1-one with formaldehyde. The asymmetric unit contains six mol­ecules. The pyrrolizine ring system in each mol­ecule is planar, the maximum atomic deviation being 0.066?(2)?Å. In the crystal structure, mol­ecules are liked together by an extensive O—H?O hydrogen-bonding network. PMID:21587820

  17. Formation of octahedral iridium(III) dihydrides from the reaction of ortho-chelated aryliridium(I) compounds with dihydrogen

    SciTech Connect

    van der Zeijden, A.A.H.; van Koten, G.; Lujik, R.; Grove, D.M.

    1988-07-01

    The reaction of Ir/sup I/(CH/sub 2/NMe/sub 2/)-2-R/sup 1/-4-R/sup 2/-6)(COD) (COD = cyclooacta-1,5-diene) with dihydrogen in CD/sub 2/Cl/sub 2/ was monitored by /sup 1/H NMR. At -20/sup 0/C quantitative formation of the novel dihydride complexes Ir/sup III/H/sub 2/(C/sub 6/H/sub 2/(CH/sub 2/NMe/sub 2/)-2-R/sup 1/-4-R/sup 2/-6)(COD) (R/sup 1/ = H, R/sup 2/ = CH/sub 2/NMe/sub 2/ (10), Me (11); R/sup 2/ = H, R/sup 1/ = H (12), Me (13), CH/sub 2/NMe/sub 2/ (14); R/sup 1/ = R/sup 2/ = CH/sub 2/NMe/sub 2/ (15)) occurs. Further reactions, the type of which depends on the bulkiness of the R/sup 1/ and R/sup 2/ groups, occur when these solutions are warmed to 0/sup 0/C. Complexes 12-14 (R/sup 2/ = H) lose H/sub 2/ to re-form Ir/sup I/(C/sub 6/H/sub 3/(CH/sub 2/NMe/sub 2/)-2-R/sup 1/-4)(COD). In contrast, complexes 10, 11, and 15 (R/sup 2/ = alkyl) react further by means of C(aryl)-H reductive elimination. For complex 15 (R/sup 1/ = CH/sub 2/NMe/sub 2/) this results in quantitative formation of 1,3,5-(Me/sub 2/NCH/sub 2/)/sub 3/C/sub 6/H/sub 3/ and IrH(COD). In Ir/sup III/H/sub 2/(C/sub 6/H/sub 3/(CH/sub 2/NMe/sub 2/)-2-R-6)(COD) (R = alkyl (10 and 11)), C(aryl)-H reductive elimination is followed by re-addition of another C(aryl)-H bond, which upon subsequent reductive elimination of H/sub 2/, yields the rearranged iridium(I) complexes Ir/sup I/(C/sub 6/H/sub 3/(CH/sub 2/NMe/sub 2/)-2-R-4)(COD). Since the rearrangement of Ir/sup I/(C/sub 6/H/sub 3/-(CH/sub 2/NMe/sub 2/)-2-R-6)(COD) to Ir/sup I/(C/sub 6/H/sub 3/(CH/sub 2/NMe/sub 2/)-2-R-4)(COD) can also be induced thermally at 60/sup 0/C, it is therefore being catalyzed by dihydrogen at 0/sup 0/C. None of these reactions with dihydrogen is attended by hydrogenation of the COD ligand.

  18. CCD and IR array controllers

    NASA Astrophysics Data System (ADS)

    Leach, Robert W.; Low, Frank J.

    2000-08-01

    A family of controllers has bene developed that is powerful and flexible enough to operate a wide range of CCD and IR focal plane arrays in a variety of ground-based applications. These include fast readout of small CCD and IR arrays for adaptive optics applications, slow readout of large CCD and IR mosaics, and single CCD and IR array operation at low background/low noise regimes as well as high background/high speed regimes. The CCD and IR controllers have a common digital core based on user- programmable digital signal processors that are used to generate the array clocking and signal processing signals customized for each application. A fiber optic link passes image data and commands to VME or PCI interface boards resident in a host computer to the controller. CCD signal processing is done with a dual slope integrator operating at speeds of up to one Megapixel per second per channel. Signal processing of IR arrays is done either with a dual channel video processor or a four channel video processor that has built-in image memory and a coadder to 32-bit precision for operating high background arrays. Recent developments underway include the implementation of a fast fiber optic data link operating at a speed of 12.5 Megapixels per second for fast image transfer from the controller to the host computer, and supporting image acquisition software and device drivers for the PCI interface board for the Sun Solaris, Linux and Windows 2000 operating systems.

  19. Elevated 1?h postload plasma glucose levels identify adults with normal glucose tolerance but increased risk of non-alcoholic fatty liver disease

    PubMed Central

    Sesti, Giorgio; Hribal, Marta Letizia; Fiorentino, Teresa Vanessa; Sciacqua, Angela; Perticone, Francesco

    2014-01-01

    Objective To determine the ability of the proposed diagnostic value of a 1-h OGTT glucose ?155mg/dL to identify individuals with non-alcoholic fatty liver disease (NAFLD) diagnosed by ultrasonography in a cohort of adult white individuals. Design The study group comprised 710 white individuals participating to the CATAnzaro MEtabolic RIsk factors (CATAMERI) Study, a cross-sectional study assessing cardio-metabolic risk factors in individuals carrying at least one risk factor including dysglycemia, overweight/obesity, hypertension, dyslipidemia. a 75 g oral Oral Glucose Tolerance Test (OGTT) was performed with 0, 30, 60, 90 and 120 min sampling for plasma glucose and insulin measurements. Cardio-metabolic risk factors including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyltransferase (GGT) were assessed in the whole cohort. Results Of the 710 participants examined, 295 had normal glucose tolerance (NGT) with 1-hour post-load plasma glucose <155 mg/dL (NGT 1h-low), 109 individuals had NGT 1h-high, 104 had isolated impaired fasting glucose (IFG), and 202 had impaired glucose tolerance (IGT). As compared with NGT 1h-low, NGT 1h-high and IGT subjects exhibited significantly higher body mass index (BMI), triglycerides, high sensitivity C reactive protein, ALT, GGT, and hepatic insulin resistance (IR), assessed by the liver IR index, as well as lower high density lipoprotein, and insulin-like growth factor-1 (IGF-1) levels. In a logistic regression analysis adjusted for age, gender, and BMI, NGT 1h-high participants had a 1.5-fold increased risk of having NAFLD and an even increased risk was observed in subjects with IGT (1.8-fold), but not in the isolated IFG group (1.01-fold). Conclusions These data suggest that the value of a 1-hour OGTT glucose ?155 mg/dL may be helpful to identify a subset of NGT individuals at risk for NAFLD. PMID:25452862

  20. Synthesis and biological evaluation of 3-hydroxymethyl-5-(1H-1,2,3-triazol) isoxazolidines.

    PubMed

    Romeo, Roberto; Giofrè, Salvatore V; Carnovale, Caterina; Campisi, Agata; Parenti, Rosalba; Bandini, Lorenzo; Chiacchio, Maria A

    2013-12-15

    A synthetic approach towards a series of 3-hydroxymethyl-5-(1H-1,2,3-triazol)isoxazolidines has been reported, according to a procedure based on the cycloaddition reaction, under microwave irradiation, of a nitrone with 1-vinyl triazoles, prepared by a click reaction of azides with alkynes. Biological tests show that the synthesized compounds are able to inhibit proliferation of follicular and anaplastic human thyroid cancer cell lines, with IC50 values ranging from 3.87 to 8.76 lM. The obtained compounds induce caspase-3 activation and DNA fragmentation prevalently in follicular human thyroid cancer cell lines. PMID:24436994

  1. Nd(III) and Dy(III) coordination compounds based on 1H-tetrazolate-5-acetic acid ligands: Synthesis, crystal structures and catalytic properties

    SciTech Connect

    Li Qiaoyun; Chen Dianyu; He Minghua [Jiangsu Laboratory of Advanced Functional Materials, Department of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu 215500, Jiangsu (China); Yang Gaowen, E-mail: ygwsx@126.com [Jiangsu Laboratory of Advanced Functional Materials, Department of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu 215500, Jiangsu (China); Shen Lei; Zhai Chun; Shen Wei; Gu Kun; Zhao Jingjing [Jiangsu Laboratory of Advanced Functional Materials, Department of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu 215500, Jiangsu (China)

    2012-06-15

    Reactions of 1H-tetrazolate-5-acetic acid(H{sub 2}tza) with Nd(NO{sub 3}){sub 3}{center_dot}6H{sub 2}O or Dy(NO{sub 3}){sub 3}{center_dot}6H{sub 2}O with the presence of KOH under solvothermal conditions, produced two new coordination compounds, [M{sub 2}(tza){sub 3}(H{sub 2}O){sub 6}]{center_dot}2H{sub 2}O [M=Nd(1), Dy(2)]. Both compounds were structurally characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Compounds 1 and 2 reveal 1D structures via bridging tza as linker. Furthermore, the compounds 1 and 2 showed a specific and good catalytic behavior for the polymerization of styrene, and the polymerization showed controlled characteristics. - Graphical Abstract: Two new coordination compounds, [M{sub 2}(tza){sub 3}(H{sub 2}O){sub 6}]{center_dot}2H{sub 2}O [M=Nd(1), Dy(2)] have been synthesis. 1 and 2 reveal 1D structures via bridging tza as linker, and showed a specific and good catalytic behavior for the polymerization of styrene. Highlights: Black-Right-Pointing-Pointer we have reported two novel compounds formed by H{sub 2}tza and Nd(III) or Dy(III). Black-Right-Pointing-Pointer Compounds 1 and 2 were found to have catalysis property for the photo-polymerization of styrene. Black-Right-Pointing-Pointer The high molecular weight polymers with narrow molecular weight distributions were obtained.

  2. Synthesis and Characterization of nido-[1,1,2,2-(CO)(4)-1,2-(PPh(3))(2)-1,2-FeIrB(2)H(5)]: A Heterobimetallaborane Analogue of nido-[B(4)H(7)](-).

    PubMed

    Bould, Jonathan; Rath, Nigam P.; Barton, Lawrence

    1996-01-01

    The synthesis and characterization of nido-[1,1,2,2-(CO)(4)-1,2-(PPh(3))(2)-1,2-FeIrB(2)H(5)] (1) is reported. 1 is formed in low yield as a degradation product from the reaction between [{&mgr;-Fe(CO)(4)}B(6)H(9)](-) and trans-Ir(CO)Cl(PPh(3))(2) in THF and is characterized from NMR, IR, and analytical data and by a single-crystal X-ray diffraction study. 1 crystallizes in the monoclinic space group P2(1)/n with a = 12.8622(12), b = 14.3313(12), c = 23.579(3) Å, beta = 97.12(2) degrees, Z = 4, V = 4257.0(8) Å(3), R(1) = 4.83%, and wR(2)()(F(2)) = 12.43%. The heterobimetallaborane structure may be viewed as a derivative of the binary boron hydride nido-[B(4)H(7)](-) and is related to the known homobimetallatetraborane analogues [Fe(2)(CO)(6)B(2)H(6)] and [Co(2)(CO)(6)B(2)H(4)]. 1 exhibits proton fluxionality in its (1)H NMR spectrum, which is related to that found in the latter two compounds. PMID:11666160

  3. Synthesis, properties, and multinuclear NMR (/sup 125/Te//sup 1/H/, /sup 13/C//sup 1/H/, /sup 1/H Studies of Di- and polytelluroether ligands

    SciTech Connect

    Hope, E.G.; Kemmitt, T.; Levason, W.

    1988-01-01

    Convenient syntheses for RTeLi (R = Me or Ph) from RLi and tellurium in tetrahydrofuran at low temperatures are described. The RTeLi react readily with organic dihalides X(CH/sub 2/)/sub n/X (X = Cl or Br), the products depending upon the temperature and the carbon chain length (n). Thus at low temperatures CH/sub 2/Cl/sub 2/ and Cl(CH/sub 2/) produce high yields of RTe(CH/sub 2/)/sub n/TeR (n = 1 or 3), but at room temperature Cl(CH/sub 2/)/sub n/ Cl (n = 2 or 3) affords R/sub 2/Te/sub 2/ olefin. 1,4-Dihalobutanes give R/sub 2/Te and Te(CH/sub 2/)/sub 3/Ch/sub 2/, while Cl(CH/sub 2/)/sub 5/Cl produced mixtures of R/sub 2/Te,RTe(CH/sub 2/)/sub 5/TeR, and Te(CH/sub 2/)/sub 4/CH/sub 2/. Preparations for RTe(CH/sub 2/)/sub 6/TeR, MeTe(CH/sub 2/)/sub 10/TeMe, and MeC(CH/sub 2/TeMe)/sub 3/ are described. PHTeLi and C(CH/sub 2/Br)/sub 4/ gave C(CH/sub 2/TePh)/sub 4/, but MeTeLi unexpectedly gave CH/sub 2/CH/sub 2/C(CH/sub 2/Te1/H, /sup 13/C//sup 1/H/, and /sup 125/Te//sup 1/H/ NMR and mass spectrometry and by the preparation of derivatives. Trends in the /sup 125/Te chemical shifts and /sup 1/J/sub Te-C/, /sup 2/J/sub Te-C/, and /sup 2/J/sub Te-H/ coupling constants are discussed and compared with the corresponding /sup 77/Se data of selenium analogues.

  4. 1H NMR study of dodecanuclear polyoxovanadate cluster {V12}

    NASA Astrophysics Data System (ADS)

    Suh, B. J.; Procissi, D.; Kögerler, P.; Micotti, E.; Lascialfari, A.; Borsa, F.

    2004-05-01

    We report 1H nuclear spin-lattice relaxation rates T1-1 in the magnetic cluster {V12}. While no critical enhancement in 1H T1-1 was found at T~|J| contrary to other antiferromagnetic molecules, the T1?-1 was observed to exhibit a peak at 19K. The different behavior is discussed in terms of critical effects in classical spins (s=5/2) vs. quantum spins (s=1/2). From the exponential drop of the proton T1-1 at low T, we obtained the gap values between the ST=0 ground state to the excited states: ?1?17K, ?2?35K, and ?3?52K.

  5. Infrared spectroelectrochemistry of bacteriochlorophylls and bacteriopheophytins: Implications for the binding of the pigments in the reaction center from photosynthetic bacteria

    PubMed Central

    Mäntele, W. G.; Wollenweber, A. M.; Nabedryk, E.; Breton, J.

    1988-01-01

    The IR spectra of the bacteriochlorophyll a and b cations and the bacteriopheophytin a and b anions were obtained by using an IR and optically transparent electrochemical cell. Prominent effects of radical formation on the vibrational spectra were found for bands assigned to the ester, keto, and acetyl C=O groups and for vibrations from macrocycle bonds. The (radical-minus-neutral) difference spectra are compared to the light-induced difference spectra of the primary donor photooxidation and the intermediary acceptor photoreduction in the reaction center of photosynthetic bacteria. Light-induced absorbance changes from bacteriochlorophyll a-containing reaction centers bear striking similarities to the electrochemically induced absorbance changes observed upon formation of bacteriochlorophyll a+in vitro. Comparison of the radical formation in vitro in a hydrogen-bonding or a nonhydrogen-bonding solvent suggests an ester C=O group hydrogen bonded in the neutral state but free in the cation state. For the keto C=O group, the same comparison indicates one free carbonyl group. The (anion-minus-neutral) difference spectra of bacteriopheophytin a and b exhibit a single band in the ester C=O frequency range. In contrast, two bands are observed in the difference spectra of the intermediary acceptor reduction in the reaction center of Rhodopseudomonas viridis. The higher frequency band exhibits a sensitivity to 1H-2H exchange, which suggests a contribution from a protonated carboxyl group of an amino acid side chain. PMID:16593991

  6. Beispiel und Übungen zur 1H-NMR Spektroskopie

    Microsoft Academic Search

    Reinhard Meusinger

    \\u000a In diesem Kapitel wird an Hand von vier Beispielen und sechs Übungen die Herangehensweise zur Auswertung von 1H-NMR Spektren demonstriert. Die Beispiele beinhalten den vollständigen und ausführlich erklärten Lösungsweg, währen es sich\\u000a bei den Übungen um Aufgabenblätter handelt, die zur selbständigen Arbeit dienen. Die vollständige Lösung wird aber direkt\\u000a im Anschluss gegeben, so dass man die eigenen Ergebnisse schnell überprüfen

  7. Reactions of nitric oxide and nitrogen dioxide with coenzyme Q: involvement of the isoprenic chain.

    PubMed

    Astolfi, Paola; Charles, Laurence; Gigmes, Didier; Greci, Lucedio; Rizzoli, Corrado; Sorana, Federico; Stipa, Pierluigi

    2013-02-28

    The formation of a di-tert-alkyl nitroxide has been observed by Electron Spin Resonance during the exposure of coenzyme CoQ(10), in both the oxidized and reduced forms, to nitrogen dioxide (?NO(2)) or to nitric oxide (?NO) in the presence of oxygen. The same kind of nitroxide has been observed also with CoQ(1), CoQ(3) or with 1-phenyl-3-methyl-2-butene, chosen as model compounds. In all cases, the formation of the nitroxide may be justified only by admitting the involvement of the isoprenic chain of the coenzymes and in particular the addition of ?NO(2) to the double bond. A mechanism which accounts for the formation of the nitroxide as well as the other compounds observed in the reactions is proposed and confirmed by a spectroscopic investigation (FT-IR, (1)H NMR, X-ray analysis) and by ESI-MS. PMID:23334659

  8. CHHC and [superscript 1]H–[superscript 1]H magnetization exchange: Analysis by experimental solid-state NMR and 11-spin density-matrix simulations

    E-print Network

    Aluas, Mihaela

    A protocol is presented for correcting the effect of non-specific cross-polarization in CHHC solid-state MAS NMR experiments, thus allowing the recovery of the [superscript 1]H–[superscript 1]H magnetization exchange ...

  9. Synthesis and x-ray structural characterization of binuclear iridium(I) and rhodium(I) hydroxypyridinate complexes. 1. Complete assignment of the /sup 1/H NMR spectra by two-dimensional and NOE techniques. The nature of inside and outside /sup 1/H chemical shift differences

    SciTech Connect

    Rodman, G.S.; Mann, K.R.

    1988-09-21

    Six new d/sup 8/-d/sup 8/ complexes, (Ir(COD)(..mu..-hp))/sub 2/, (Ir(COD)(..mu..-mhp))/sub 2/, (Ir(COD)(..mu..-chp))/sub 2/, (Ir(COD)(..mu..-2hq))/sub 2/, (Rh(COD)(..mu..-hp))/sub 2/, and (Rh(COD)(..mu..-mhp))/sub 2/ (hp = 2-hydroxyphridinate, mhp = 6-methyl-2-hydroxypyridinate, chp = 6-chloro-2-hydroxypyridinate, 2hq = 2-hydroxyquinolate, COD = 1,5-cyclooctadiene), were synthesized and characterized by /sup 1/H NMR, /sup 13/C NMR, and IR spectroscopy and FAB mass spectrometry. X-ray crystallographic analyses of the isostructural (M(COD)(..mu..-mhp))/sub 2/ (M = Ir and Rh) complexes confirmed the binuclear nature of the complexes. The complete assignment of the /sup 1/H NMR spectrum of (Ir(COD)(..mu..-hp))/sub 2/ (and by analogy, the spectra of the other five complexes) was carried out with selective decoupling, nuclear Overhauser effect (NOE), and two-dimensional NMR techniques. The NOE observed between hp proton H5 and COD proton H15 allowed the precise assignment of all 12 COD resonances. Olefinic proton H12 (trans to N and outside) resonates downfield of olefinic proton H11 (trans to N and inside). Olefininc proton H15 (trans to O and outside) resonates upfield of olefinic proton H16 (trans to O and inside). The endo methylene protons resonate upfield of the exo methylene protons. The inside/outside chemical shift differences observed for these compounds are ascribed to steric and magnetic anisotropy effects. The crystallographic data are presented. The molecular structure of the complexes is discussed in detail. 39 references, 5 figures, 9 tables.

  10. Ultrafast 2D-IR spectroelectrochemistry of flavin mononucleotide

    NASA Astrophysics Data System (ADS)

    El Khoury, Youssef; Van Wilderen, Luuk J. G. W.; Bredenbeck, Jens

    2015-06-01

    We demonstrate the coupling of ultrafast two-dimensional infrared (2D-IR) spectroscopy to electrochemistry in solution and apply it to flavin mononucleotide, an important cofactor of redox proteins. For this purpose, we designed a spectroelectrochemical cell optimized for 2D-IR measurements in reflection and measured the time-dependent 2D-IR spectra of the oxidized and reduced forms of flavin mononucleotide. The data show anharmonic coupling and vibrational energy transfer between different vibrational modes in the two redox species. Such information is inaccessible with redox-controlled steady-state FTIR spectroscopy. The wide range of applications offered by 2D-IR spectroscopy, such as sub-picosecond structure determination, IR band assignment via energy transfer, disentangling reaction mixtures through band connectivity in the 2D spectra, and the measurement of solvation dynamics and chemical exchange can now be explored under controlled redox potential. The development of this technique furthermore opens new horizons for studying the dynamics of redox proteins.

  11. Ultrafast 2D-IR spectroelectrochemistry of flavin mononucleotide.

    PubMed

    El Khoury, Youssef; Van Wilderen, Luuk J G W; Bredenbeck, Jens

    2015-06-01

    We demonstrate the coupling of ultrafast two-dimensional infrared (2D-IR) spectroscopy to electrochemistry in solution and apply it to flavin mononucleotide, an important cofactor of redox proteins. For this purpose, we designed a spectroelectrochemical cell optimized for 2D-IR measurements in reflection and measured the time-dependent 2D-IR spectra of the oxidized and reduced forms of flavin mononucleotide. The data show anharmonic coupling and vibrational energy transfer between different vibrational modes in the two redox species. Such information is inaccessible with redox-controlled steady-state FTIR spectroscopy. The wide range of applications offered by 2D-IR spectroscopy, such as sub-picosecond structure determination, IR band assignment via energy transfer, disentangling reaction mixtures through band connectivity in the 2D spectra, and the measurement of solvation dynamics and chemical exchange can now be explored under controlled redox potential. The development of this technique furthermore opens new horizons for studying the dynamics of redox proteins. PMID:26049436

  12. Effect of Exercise on the Creatine Resonances in 1H MR Spectra of Human Skeletal Muscle

    NASA Astrophysics Data System (ADS)

    Kreis, R.; Jung, B.; Slotboom, J.; Felblinger, J.; Boesch, C.

    1999-04-01

    1H MR spectra of human muscles were recorded before, during, and after fatiguing exercise. In contrast to expectations, it was found that the spectral contributions of creatine/phosphocreatine (Cr/PCr) were subject to change as a function of exercise. In particular, the dipolar-coupled methylene protons of Cr/PCr were found to be reduced in intensity in proportion to the co-registered PCr levels. Recovery after exercise and behavior under ischemic conditions provide further evidence to suggest that the contributions of the CH2protons of Cr/PCr to1H MR spectra of human musclein vivoreflect PCr rather than Cr levels. Variation of experimental parameters showed that this effect is not due to a trivial change in relaxation times. At present it can only be speculated about why the Cr resonances have reduced NMR visibility. If temporary binding to macromolecules should be involved, the free Cr concentration-important for equilibrium calculations of the creatine kinase reaction-might be different from what was previously assumed.

  13. Dynamics in the Isotropic Phase of Nematogens Using 2D IR Vibrational Echo Measurements on Natural Abundance 13

    E-print Network

    Fayer, Michael D.

    Dynamics in the Isotropic Phase of Nematogens Using 2D IR Vibrational Echo Measurements on Natural at 2161 cm-1 , indicative of a thiocyanate as opposed to isothiocyanate (generally broader).2-6 1 H NMR ionization (solvent: acetonitrile) showed the molecular ion peak at 281 m/z in agreement with calculated mass

  14. Facile solvothermal synthesis of abnormal growth of one-dimensional ZnO nanostructures by ring-opening reaction of polyvinylpyrrolidone

    NASA Astrophysics Data System (ADS)

    Xu, G.; Wang, X. L.; Liu, G. Z.

    2015-02-01

    Abnormal growth of one-dimensional (1-D) ZnO nanostructures (NSs) have been accomplished with the assistance of polyvinylpyrrolidone (PVP) under a super high alkaline alcoholic solvothermal condition. The products were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. The effect of synthetic conditions, such as reaction temperature and the addition of PVP, on the morphologies of ZnO products were investigated. The results show that PVP molecules had the significant role in the transformation of morphologies of ZnO NSs ranging from nanorods, nanoparticles to pyramids, as well as flower-like assembly features. The possible growth mechanism of ZnO pyramids was proposed based on ring-opening reaction of PVP.

  15. New IR detectors pig-tailed with IR fibers

    NASA Astrophysics Data System (ADS)

    Artiouchenko, Viatcheslav G.; Chekanova, Galina V.; Lartsev, Ivan Y.; Lobachev, Vladimir A.; Nikitine, Mikhail S.

    2003-09-01

    New generation of Mercury-Cadmium-Telluride (MCT) high performance infrared radiation (IR) detectors with IR-fiber input has been developed and fabricated. This new product is originated from 25 years experience in MCT detectors and IR fiber optics technologies. Range of products includes single- and multi-element detectors designed for registration of optical signals in spectral range from 2 to 18 ?m. Detectors design is integrated or modular and includes package, sensitive element, cooling system, operating temperature sensor, optical components such as narrow band-pass filter and/or lens and/or different kind of optical window, optical connection unit and fiber pig-tail or fiber cable. Cooling system options include thermoelectric cooler, long-holding time dewar filled with liquid nitrogen, Joule-Thomson micro-liquidizer and Stirling-cycle cooler. Registered infrared radiation is delivered to sensitive area of detector through either Polycrystalline InfraRed (PIR-) Fiber (4 - 18 ?m) or Chalcogenide IR-glass (CIR-) Fiber (2 - 6 ?m). Unique feature intrinsic to Hg1-xCdxTe (MCT) alloys to form continuous series of alloy compositions "x" with proportionally changed energy gap Eg(x,T) allows to tune spectral responsivity of detector sensitive element with ordered spectral range and hence to use every time the highest sensitive detector.

  16. Reduction of 2- and 3-Acylpyrroles. A New Synthesis of the Pyrrolo[1,2- b]cinnolin-10-one Ring System from 1-(4-Methylphenyl)sulfonyl-1 H-pyrrole

    Microsoft Academic Search

    Athanasios Kimbaris; George Varvounis

    2000-01-01

    Reduction of (2-nitrophenyl)(1H-pyrrol-2-yl)methanone 4 with zinc and ammonium chloride gave 5,10-dihydro-pyrrolo[1,2-b]cinnolin-10-one 5 and (2-hydroxylaminophenyl)(1H-pyrrol-2-yl)methanone 6 whereas reduction of 4 with zinc and sodium hydroxide gave only 5. Reaction of (2-nitrophenyl)(1H-pyrrol-3-yl)methanone 10 with zinc and ammonium chloride or zinc and sodium hydroxide afforded (2-nitrosophenyl)(1H-pyrrol-3-yl)methanone 11 and 2-aminophenyl)(1H-pyrrol-3-yl)methanone 12 or 12 as a single product, respectively. Sodium borohydride reduction of (2-nitrophenyl)(1-methyl-1H-pyrrol-2-yl)methanone 13

  17. Selective formation of glycosidic linkages of N-unsubstituted 4-hydroxyquinolin-2-(1H)-ones.

    PubMed

    Kimmel, Roman; Kafka, Stanislav; Kosmrlj, Janez

    2010-04-19

    A comparative study for selective glucosylation of N-unsubstituted 4-hydroxyquinolin-2(1H)-ones into 4-(tetra-O-acetyl-beta-D-glucopyranosyloxy)quinolin-2(1H)-ones is reported. Four glycosyl donors including tetra-O-acetyl-alpha-D-glucopyranosyl bromide, beta-D-glucose pentaacetate, glucose tetraacetate and tetra-O-acetyl-alpha-D-glucopyranosyl trichloroacetimidate were tested, along with different promoters and reaction conditions. The best results were obtained with tetra-O-acetyl-alpha-D-glucopyranosyl bromide with Cs(2)CO(3) in CH(3)CN. In some cases the 4-O-glucosylation of the quinolinone ring was accompanied by 2-O-glucosylation yielding the corresponding 2,4-bis(tetra-O-acetyl-beta-D-glucopyranosyloxy)quinoline. Next, 4-(tetra-O-acetyl-beta-D-glucopyranosyloxy)quinolin-2(1H)-ones were deacetylated into 4-(beta-D-glucopyranosyloxy)quinolin-2(1H)-ones with Et(3)N in MeOH. In some instances the deacetylation was accompanied by the sugar-aglycone bond cleavage. Structure elucidation, complete assignment of proton and carbon resonances as well as assignment of anomeric configuration for all the products under investigation were performed by 1D and 2D NMR spectroscopy. PMID:20206337

  18. Inhibition of myeloperoxidase: evaluation of 2H-indazoles and 1H-indazolones.

    PubMed

    Roth, Aaron; Ott, Sean; Farber, Kelli M; Palazzo, Teresa A; Conrad, Wayne E; Haddadin, Makhluf J; Tantillo, Dean J; Cross, Carroll E; Eiserich, Jason P; Kurth, Mark J

    2014-11-15

    Myeloperoxidase (MPO) produces hypohalous acids as a key component of the innate immune response; however, release of these acids extracellularly results in inflammatory cell and tissue damage. The two-step, one-pot Davis-Beirut reaction was used to synthesize a library of 2H-indazoles and 1H-indazolones as putative inhibitors of MPO. A structure-activity relationship study was undertaken wherein compounds were evaluated utilizing taurine-chloramine and MPO-mediated H2O2 consumption assays. Docking studies as well as toxicophore and Lipinski analyses were performed. Fourteen compounds were found to be potent inhibitors with IC50 values <1?M, suggesting these compounds could be considered as potential modulators of pro-oxidative tissue injury pertubated by the inflammatory MPO/H2O2/HOCl/HOBr system. PMID:25438766

  19. 60 MHz (1)H NMR spectroscopy for the analysis of edible oils.

    PubMed

    Parker, T; Limer, E; Watson, A D; Defernez, M; Williamson, D; Kemsley, E Kate

    2014-05-01

    We report the first results from a new 60 MHz (1)H nuclear magnetic resonance (NMR) bench-top spectrometer, Pulsar, in a study simulating the adulteration of olive oil with hazelnut oil. There were qualitative differences between spectra from the two oil types. A single internal ratio of two isolated groups of peaks could detect hazelnut oil in olive oil at the level of ?13%w/w, whereas a whole-spectrum chemometric approach brought the limit of detection down to 11.2%w/w for a set of independent test samples. The Pulsar's performance was compared to that of Fourier transform infrared (FTIR) spectroscopy. The Pulsar delivered comparable sensitivity and improved specificity, making it a superior screening tool. We also mapped NMR onto FTIR spectra using a correlation-matrix approach. Interpretation of this heat-map combined with the established annotations of the NMR spectra suggested a hitherto undocumented feature in the IR spectrum at ?1130 cm(-1), attributable to a double-bond vibration. PMID:24850979

  20. Synthesis, crystal structures and DFT studies of 1-[2-(5-methyl-2-benzoxazolinone-3-yl)acetyl]-3-phenyl-5-(3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazole and 1-[2-(5-chloro-2-benzoxazolinone-3-yl)acetyl]-3-phenyl-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazole

    NASA Astrophysics Data System (ADS)

    ?ahin, Zarife Sibel; Salg?n-Gök?en, Umut; Gökhan-Kelekçi, Nesrin; I??k, ?amil

    2011-12-01

    The title compounds, 1-[2-(5-methyl-2-benzoxazolinone-3-yl)acetyl]-3-phenyl-5-(3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazole ( 5a) and 1-[2-(5-chloro-2-benzoxazolinone-3-yl)acetyl]-3-phenyl-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazole ( 5b), were synthesized. The crystal and molecular structures of 5a and 5b have been determined by elemental analyses, IR, 1H NMR, ESI-MS and single-crystal X-ray diffraction. Molecular geometries of 5a and 5b in the ground state have been calculated using the density functional method (DFT) with B3LYP/6-31G(d,p) basis set and compared with the experimental data. In addition, the molecular electrostatic potential maps and frontier molecular orbitals of 5a and 5b were performed.

  1. Ruthenium-catalyzed oxidative coupling of 2-aryl-4-quinazolinones with olefins: synthesis of pyrrolo[2,1-b]quinazolin-9(1H)-one motifs.

    PubMed

    Zheng, Yong; Song, Wei-Bin; Zhang, Shu-Wei; Xuan, Li-Jiang

    2015-06-21

    A ruthenium-catalyzed oxidative coupling of 2-aryl-quinazolinones with olefins via C-H bond activation followed by an intramolecular aza-Michael reaction is described. This strategy allows the direct and efficient construction of pyrrolo[2,1-b]quinazolin-9(1H)-one scaffolds. PMID:25996242

  2. Efficient solid-phase synthesis of 4,5-dihydro-1,2,4-triazin-6(1 H)-ones

    Microsoft Academic Search

    Damien Boeglin; Sonia Cantel; Jean Martinez; Jean-Alain Fehrentz

    2003-01-01

    A new and easy protocol for the formation of substituted 4,5-dihydro-1,2,4-triazin-6(1H)-ones was developed on solid support. The heterocyclic compounds were formed by nucleophilic reaction of hydrazine on thioamide esters. As cyclization was concomitant with cleavage from the support, substituted 4,5-dihydrotriazinones were obtained in high purity.

  3. Theoretical studies of Ir5Th and Ir5Ce nanoscale precipitates in Ir

    SciTech Connect

    Morris, James R [ORNL] [ORNL; Averill, Frank [ORNL] [ORNL; Cooper, Valentino R [ORNL] [ORNL

    2014-01-01

    Experimentally, it is known that very small amounts of thorium and/or cerium added to iridium metal form a precipitate, Ir5Th / Ir5Ce, which improves the high temperature mechanical properties of the resulting alloys. We demonstrate that there are low-energy configurations for nano-scale precipitates of these phases in Ir, and that these coherent arrangements may assist in producing improved mechanical properties. One precipitate/matrix orientation gives a particularly low interfacial energy, and a low lattice misfit. Nanolayer precipitates with this orientation are found to be likely to form, with little driving force to coarsen. The predicted morphology of the precipitates and their orientation with the matrix phase provide a potential experiment that could be used to test these predictions.

  4. IR super-resolution microspectroscopy and its application to single cells.

    PubMed

    Sakai, Makoto; Inoue, Keiichi; Fujii, Masaaki

    2013-01-01

    For many years, spatial resolution is the most critical problem in IR microspectroscopy. This is because the spatial resolution of a conventional infrared microscope is restricted by the diffraction limit, which is almost the same as the wavelength of IR light, ranging from 2.5 to 25 ?m. In the recent years, we have developed two novel types of far-field IR super-resolution microscopes using 2-color laser spectroscopies, those are transient fluorescence detected IR (TFD-IR) spectroscopy and vibrational sum-frequency generation (VSFG) spectroscopy. In these ways, because both transient fluorescence and VSFG signal have a wavelength in the visible region, the image is observed at the resolution of visible light, which is about 10 times smaller than that of IR light (that is, IR super-resolution). By using these techniques, we can map the specific IR absorption band with sub-micrometer spatial resolution, visualization of the molecular structure and reaction dynamics in a non-uniform environment such as a cell becomes a possibility. In the present reviews, we introduce our novel IR super-resolution microspectroscopy and its application to single cells in detail. PMID:22356113

  5. Facile synthesis of [(NHC)MX(cod)] and [(NHC)MCl(CO)2] (M = Rh, Ir; X = Cl, I) complexes.

    PubMed

    Savka, R; Plenio, H

    2015-01-21

    The reactions of [MCl(cod)]2 (M = Rh, Ir) with different NHC·HX (X = Cl, I), K2CO3 in technical grade acetone under air provide simple access to various [(NHC)MX(cod)] complexes; a facile one-pot synthesis of [(NHC)MCl(CO)2] (M = Rh, Ir) is also reported. PMID:25437103

  6. Fingerprinting zein by IR analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zein, the dominant protein in corn, is a coproduct of the ethanol production industry. The protein content and purity of commercially available zein can vary widely depending on the source and production method. Infrared Spectroscopy Analysis (IR) was used to differentiate between zein samples of ...

  7. IR interferometers using modern cameras

    NASA Astrophysics Data System (ADS)

    Ai, Chiayu

    1997-11-01

    Laser interferometers have been used widely in the optics and disk drive industries. Often the surface of the sample is either too curved to resolve the fringes or too rough to reflect the incident beam back into the interferometer. Illuminating at a graze incident angle effectively increases the equivalent wavelength, and hence the reflectivity, but the image of a circular aperture becomes elliptical. Lasers with a long IR wavelength seem to be the solution. However,the spatial resolution of the vidicon cameras is usually poor, and the image lag is often too long. These limit the accuracy of an IR phase-shifting interferometer. Recently, we have designed tow types of interferometers for 3.39 micrometers and 10.6 micrometers using an InSb array and a micro- bolometer array, respectively. These modern cameras have a high resolution and hence greatly extend the range of measurable material from a blank to a finished optics. Because the refractive index of the optical material at the IR wavelength is usually very high, the anti-reflection coating of the optics at IR is more critical than that at a visible wavelength. The interferometer's design, the resolution, the dependence of the fringe contrast on the sample roughness, and the measurement results of various samples are presented.

  8. MARYLAND COASTAL BAYS IR 2002

    EPA Science Inventory

    The Maryland Coastal Bays Program Implementation Review (IR) summarizes the progress and challenges ahead for the Program through examination of its activities in relation to the CCMP. During the CCMP planning phase the stakeholders prioritized the actions and determined the impl...

  9. Preparation of Pt/Irx(IrO2)10 - x bifunctional oxygen catalyst for unitized regenerative fuel cell

    NASA Astrophysics Data System (ADS)

    Kong, Fan-Dong; Zhang, Sheng; Yin, Ge-Ping; Zhang, Na; Wang, Zhen-Bo; Du, Chun-Yu

    2012-07-01

    Bifunctional Pt/Irx(IrO2)10 - x (x < 10) catalyst for unitized regenerative fuel cell (URFC) has been prepared by depositing Pt on Irx(IrO2)10 - x support which is obtained initially from Adams fusion method. X-ray diffraction and transmission electron microscopy show that ultrafine and narrow distributed Pt/Ir3(IrO2)7 nanocomposites are formed. Electrochemical measurements demonstrate that among the series of catalysts studied, Pt/Ir3(IrO2)7 catalyst possesses the highest electrochemical surface area (24.74 m2 g-1) and the highest activity towards oxygen reduction reaction (ORR) (21.71 mA mg-1 at 0.85 V). Meanwhile, considerably high activity towards oxygen evolution reaction (OER) (42.35 mA mg-1 at 1.55 V) is also observed for Pt/Ir3(IrO2)7 catalyst. Kinetic analyses indicate that ORR on Pt/Ir3(IrO2)7 catalyst follows four-electron mechanism. This work opens a new way to fabricate efficient bifunctional oxygen catalyst for URFC.

  10. The 1H NMR Profile of Healthy Dog Cerebrospinal Fluid

    PubMed Central

    Musteata, Mihai; Nicolescu, Alina; Solcan, Gheorghe; Deleanu, Calin

    2013-01-01

    The availability of data for reference values in cerebrospinal fluid for healthy humans is limited due to obvious practical and ethical issues. The variability of reported values for metabolites in human cerebrospinal fluid is quite large. Dogs present great similarities with humans, including in cases of central nervous system pathologies. The paper presents the first study on healthy dog cerebrospinal fluid metabolomic profile using 1H NMR spectroscopy. A number of 13 metabolites have been identified and quantified from cerebrospinal fluid collected from a group of 10 mix breed healthy dogs. The biological variability as resulting from the relative standard deviation of the physiological concentrations of the identified metabolites had a mean of 18.20% (range between 9.3% and 44.8%). The reported concentrations for metabolites may be used as normal reference values. The homogeneity of the obtained results and the low biologic variability show that the 1H NMR analysis of the dog’s cerebrospinal fluid is reliable in designing and interpreting clinical and therapeutic trials in dogs with central nervous system pathologies. PMID:24376499

  11. Dynamics-based selective 2D (1)H/(1)H chemical shift correlation spectroscopy under ultrafast MAS conditions.

    PubMed

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-05-28

    Dynamics plays important roles in determining the physical, chemical, and functional properties of a variety of chemical and biological materials. However, a material (such as a polymer) generally has mobile and rigid regions in order to have high strength and toughness at the same time. Therefore, it is difficult to measure the role of mobile phase without being affected by the rigid components. Herein, we propose a highly sensitive solid-state NMR approach that utilizes a dipolar-coupling based filter (composed of 12 equally spaced 90° RF pulses) to selectively measure the correlation of (1)H chemical shifts from the mobile regions of a material. It is interesting to find that the rotor-synchronized dipolar filter strength decreases with increasing inter-pulse delay between the 90° pulses, whereas the dipolar filter strength increases with increasing inter-pulse delay under static conditions. In this study, we also demonstrate the unique advantages of proton-detection under ultrafast magic-angle-spinning conditions to enhance the spectral resolution and sensitivity for studies on small molecules as well as multi-phase polymers. Our results further demonstrate the use of finite-pulse radio-frequency driven recoupling pulse sequence to efficiently recouple weak proton-proton dipolar couplings in the dynamic regions of a molecule and to facilitate the fast acquisition of (1)H/(1)H correlation spectrum compared to the traditional 2D NOESY (Nuclear Overhauser effect spectroscopy) experiment. We believe that the proposed approach is beneficial to study mobile components in multi-phase systems, such as block copolymers, polymer blends, nanocomposites, heterogeneous amyloid mixture of oligomers and fibers, and other materials. PMID:26026440

  12. Dynamics-based selective 2D 1H/1H chemical shift correlation spectroscopy under ultrafast MAS conditions

    NASA Astrophysics Data System (ADS)

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-05-01

    Dynamics plays important roles in determining the physical, chemical, and functional properties of a variety of chemical and biological materials. However, a material (such as a polymer) generally has mobile and rigid regions in order to have high strength and toughness at the same time. Therefore, it is difficult to measure the role of mobile phase without being affected by the rigid components. Herein, we propose a highly sensitive solid-state NMR approach that utilizes a dipolar-coupling based filter (composed of 12 equally spaced 90° RF pulses) to selectively measure the correlation of 1H chemical shifts from the mobile regions of a material. It is interesting to find that the rotor-synchronized dipolar filter strength decreases with increasing inter-pulse delay between the 90° pulses, whereas the dipolar filter strength increases with increasing inter-pulse delay under static conditions. In this study, we also demonstrate the unique advantages of proton-detection under ultrafast magic-angle-spinning conditions to enhance the spectral resolution and sensitivity for studies on small molecules as well as multi-phase polymers. Our results further demonstrate the use of finite-pulse radio-frequency driven recoupling pulse sequence to efficiently recouple weak proton-proton dipolar couplings in the dynamic regions of a molecule and to facilitate the fast acquisition of 1H/1H correlation spectrum compared to the traditional 2D NOESY (Nuclear Overhauser effect spectroscopy) experiment. We believe that the proposed approach is beneficial to study mobile components in multi-phase systems, such as block copolymers, polymer blends, nanocomposites, heterogeneous amyloid mixture of oligomers and fibers, and other materials.

  13. In vitro interaction of selected phospholipid species with mercuric chloride using Fourier transform sup 1 H-NMR

    SciTech Connect

    Shinada, Masayuki; Muto, Hajime; Takizawa, Yukio (Akita Univ. (Japan))

    1991-09-01

    Many studies on the mercury toxicities have been accumulated since the outbreak of Minamata Disease.' There have been few reports on the reaction mechanisms of mercurials with phospholipids which substantially locate in biological membranes, although the interactions of nucleotides or nucleosides with mercurials have been reported. Recently, the study on the interaction of mercuric chloride (HgCl{sub 2}) with amino polar heads of model membranes containing phosphatidylserine (PS) and phosphatidylethanolamine (PE) has been reported, as the results from the fluorescence polarization analysis using 1,6-diphenyl-1,3,5-hexatriene. The authors demonstrate here the interactions of dioleoylphosphatidylethanolamine (DOPE) and dioleoylphosphatidylcholine (DOPC) with HgCl{sub 2}, using Fourier transform {sup 1}H-NMR ({sup 1}H-FT-NMR).

  14. Synthesis, crystal structure, HF and DFT calculations of 1-(2-chlorobenzyl)-N-(1-(2-chlorobenzyl)-4,5-dihydro-1H-imidazol-2-yl) -1H-benzimidazol-2-amine

    SciTech Connect

    Yueksektepe, Cigdem, E-mail: yuksekc@yahoo.com [Cankiri Karatekin University, Department of Physics, Faculty of Science (Turkey); Caliskan, Nezihe [Ondokuz Mayis University, Department of Physics, Faculty of Arts and Sciences (Turkey); Genc, Murat [Adiyaman University, Department of Chemistry, Faculty of Arts and Sciences (Turkey); Servi, Sueleyman [Firat University, Department of Chemistry, Faculty of Science (Turkey)

    2010-12-15

    The titled compound (1), has been synthesized and characterized by IR and {sup 1}H-NMR spectroscopy, and single crystal X-ray diffraction. The compound crystallizes in the triclinic space group P-1. The crystal structure is stabilized by C-H-{pi} and aromatic {pi}-{pi} interactions. There are also intramolecular N-H-N and C-H-N hydrogen bonds in the molecule. The use of quantum chemical calculations to characterise and optimise the choice of material is illustrated by ab initio treatments. Vibrational frequencies and LUMO-HOMO energy difference of 1 have also been investigated by Density functional theory (DFT) and Hartree-Fock (HF) calculations. Calculated frequencies are in good agreement with the corresponding experimental data.

  15. In-beam {gamma}-ray and {alpha}-decay spectroscopy of {sup 170}Ir

    SciTech Connect

    Hadinia, B.; Cederwall, B.; Wyss, R.; Johnson, A.; Lagergren, K.; Andgren, K.; Baeck, T.; Liotta, R. J.; Sandzelius, M. [Department of Physics, Royal Institute of Technology, SE-10691 Stockholm (Sweden); Joss, D. T.; Appelbe, D. E.; Barton, C. J.; Warner, D. D. [CCLRC, Daresbury Laboratory, Daresbury, Warrington, WA4 4AD (United Kingdom); Page, R. D.; Simpson, J.; Wiseman, D. R. [Oliver Lodge Laboratory, Department of Physics, University of Liverpool, Liverpool, L69 7ZE (United Kingdom); Scholey, C.; Eeckhaudt, S.; Grahn, T.; Greenlees, P. [Department of Physics, University of Jyvaeskylae, Post Office Box 35, University of Jyvaeskylae, FIN-40014 Jyvaeskylae (Finland)] (and others)

    2007-10-15

    Excited states in the highly neutron deficient odd-odd nucleus {sup 170}Ir have been investigated. The experiment was performed using the {sup 112}Sn({sup 60}Ni, pn){sup 170}Ir reaction and employing the recoil-decay tagging technique. Gamma rays were detected using the JUROGAM {gamma}-ray spectrometer and those belonging to {sup 170}Ir were selected based on recoil identification provided by the RITU gas-filled recoil separator and the GREAT spectrometer at the RITU focal plane. A partial level scheme of {sup 170}Ir is presented for the first time. New {alpha}-decay branches are assigned to {sup 170}Ir and a tentative level structure for {sup 166}Re is deduced from a study of the {alpha}-decay fine structure and the associated {alpha}-{gamma} correlations.

  16. Mechanism of efficient anti-Markovnikov olefin hydroarylation catalyzed by homogeneous Ir(III) complexes†

    Microsoft Academic Search

    Gaurav Bhalla; Steven M. Bischof; Somesh K. Ganesh; Xiang Yang Liu; C. J. Jones; Andrey Borzenko; William J. Tenn; Daniel H. Ess; Brian G. Hashiguchi; Kapil S. Lokare; Chin Hin Leung; Jonas Oxgaard; William A. Goddard; Roy A. Periana

    2011-01-01

    3 )-(acac-O,O)2)2 and (R-Ir(acac-O,O)2(L)) (R = acetylacetonato, CH3 ,C H 2CH3, Ph, or CH2CH2Ph, and L = H2 Oo r pyridine) Ir(III) complexes was studied by experimental methods. The system is selective for generating the anti-Markovnikov product of linear alkylarenes (61 : 39 for benzene + propylene and 98 : 2 for benzene + styrene). The reaction mechanism was found

  17. Reaction of cyanamides with N,N -binucleophiles

    Microsoft Academic Search

    A. S. Shestakov; N. V. Gusakova; Kh. S. Shikhaliev; A. V. Zagoruiko

    2006-01-01

    Reactions of 4,6-dimethylpyrimidin-2-yl-and aroylcyanamides with benzene-1,2-diamine, ethylenediamine, cyclohexane-1,2-diamine,\\u000a and naphthalene-1,8-diamine leads to 1H-benzimidazol-2-amine, imidazolidin-2-imine, perhydrobenzimidazol-2-imine, and 1H-perimidin-2-amine derivatives, respectively.

  18. (1)H NMR brain metabonomics of scrapie exposed sheep.

    PubMed

    Scano, Paola; Rosa, Antonella; Incani, Alessandra; Maestrale, Caterina; Santucciu, Cinzia; Perra, Daniela; Vascellari, Sarah; Pani, Alessandra; Ligios, Ciriaco

    2015-06-16

    While neurochemical metabolite modifications, determined by different techniques, have been diffusely reported in human and mice brains affected by transmissible spongiform encephalopathies (TSEs), this aspect has been little studied in the natural animal hosts with the same pathological conditions so far. Herein, we investigated, by high resolution (1)H NMR spectroscopy and multivariate statistical data analysis, the brain metabolite profile of sheep exposed to a scrapie agent in a naturally affected flock. On the basis of clinical examinations and western blotting analysis for the pathological prion protein (PrP(Sc)) in brain tissues, sheep were catalogued as not infected (H), infected with clinical signs (S), and infected without clinical signs (A). By discriminant analysis of spectral data, comparing S vs. H, we found a different metabolite distribution, with inosine, cytosine, creatine, and lactate being higher in S than in H brains, while the branched chain amino acids (leucine, isoleucine, and valine), phenylalanine, uracil, tyrosine, gamma-amino butyric acid, total aspartate (aspartate + N-acetyl aspartate) being lower in S. By a soft independent modelling of class analogy approach, 1 out of 3 A samples was assigned to class H. Furthermore, A brains were found to be higher in choline and choline-containing compounds. By means of partial least squares regression, an excellent correlation was found between the PrP(Sc) amount and the (1)H NMR metabolite profile of infected (S and A) sheep, and the metabolite mostly correlated with PrP(Sc) was alanine. The overall results, obtained using different chemometric tools, were able to describe a brain metabolite profile of infected sheep with and without clinical signs, compared to healthy ones, and indicated alanine as a biomarker for PrP(Sc) amounts in scrapie brains. PMID:25959287

  19. LATE REACTION, PERSISTENT REACTION AND DOUBTFUL ALLERGIC REACTION: THE PROBLEMS OF INTERPRETATION

    PubMed Central

    Sarma, Nilendu

    2009-01-01

    The standard method of patch test reading is to read the test site for any positive allergy at 48 hr and then again at 72/96 hr. A late reading on the seventh day is also advised to exclude the irritant reaction (IR) and to notice some delayed development of allergic reaction. However, multiple visits are often difficult for the patient; therefore, this late reading is sometimes omitted. Here a case of plantar hyperkeratosis, due to allergic contact dermatitis, is reported with some insight into interpretation of the patch test. The patient showed delayed patch test reaction to formaldehyde and colophony, which has never been reported before. PMID:20049272

  20. Ultrafast 2D IR Vibrational Echo Spectroscopy

    E-print Network

    Fayer, Michael D.

    Ultrafast 2D IR Vibrational Echo Spectroscopy JUNRONG ZHENG, KYUNGWON KWAK, AND M. D. FAYER The experimental technique and applications of ultrafast two- dimensional infrared (2D IR) vibrational echo systems. The form and time evolution of the 2D IR spectrum permits examination of processes that cannot

  1. Using graded relevance assessments in IR evaluation

    Microsoft Academic Search

    Jaana Kekäläinen; Kalervo Järvelin

    2002-01-01

    This paper proposes evaluation methods based on the use of non-dichotomous relevance judgements in IR experi- ments. It is argued that evaluation methods should credit IR methods for their ability to retrieve highly relevant documents. This is desirable from the user point of view in modern large IR environments. The proposed methods are (1) a novel application of P-R curves

  2. Dynamic metabolites profile of cerebral ischemia/reperfusion revealed by 1H NMR-based metabolomics contributes to potential biomarkers

    PubMed Central

    Wang, Yun; Wang, Yi-Gang; Ma, Teng-Fei; Li, Mei; Gu, Shu-Ling

    2014-01-01

    Current metabolomic studies of ischemic brain mainly attach importance on a certain ischemic period, are lack of data about dynamic metabolites in ischemic stroke process, especially early period. Thus, in this study, 1H NMR spectroscopy was used to investigate biochemical changes in the early stages of rats’ focal cerebral ischemia reperfusion (I/R) injury. Serum samples of 0, 0.5, 1, 3, 6, 12, 24 h of reperfusion, based on multivariate data analyses, were tested to analyze the changing of metabolites during the early disease process. Partial least squares-discriminant analysis scores plots of the 1H NMR data revealed clear differences among the experiment groups. Combination the results of loading plot and t-test, we found that 13 metabolites were changed significantly. Among that, malonic acid and glycine are the most noticeable variable metabolites. Dramatic changed malonic acid and glycine most probably served as biomarkers in this study. These findings help us understand the biochemical metabolite changes in early ischemic stroke stages, especially different periods. That may be conducive to distinguish at-risk individuals, benefit early diagnosis and understand the dynamic pathogenesis of early cerebral ischemia. PMID:25120785

  3. Isomeric luminescent Zn(II) coordination polymers based on pyridinecarboxylate and 5-methyl-1H-tetrazole ligands

    NASA Astrophysics Data System (ADS)

    An, Zhe; Gao, Jing; Zhu, Ling

    2013-12-01

    Two new metal-organic frameworks, namely [Zn(nic)(mtz)]n (1) and [Zn(isonic)(mtz)]n (2) (Hnic = nicotinic acid, Hisonic = isonicotinic acid, Hmtz = 5-methyl-1H-tetrazole), have been obtained through the solvothermal reactions of Zn(NO3)2, Htmz and Hnic or Hisonic. Single crystal X-ray diffraction analysis reveals that compound 1 features a 2D layered structure with sql topology, which is further extended into a 3D supramolecular framework via weak CH…? interactions, and compound 2 is 2-fold interpenetrated 3D framework with dia topology. Luminescent investigation shows that both of them emit blue luminescence at room temperature.

  4. 40 CFR 721.10587 - 1H-Pyrazole, 3,4-dimethyl-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false 1H-Pyrazole, 3,4-dimethyl-. 721.10587...Chemical Substances § 721.10587 1H-Pyrazole, 3,4-dimethyl-. (a) Chemical...chemical substance identified as 1H-pyrazole, 3,4-dimethyl- (PMN...

  5. 40 CFR 721.10587 - 1H-Pyrazole, 3,4-dimethyl-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false 1H-Pyrazole, 3,4-dimethyl-. 721.10587...Chemical Substances § 721.10587 1H-Pyrazole, 3,4-dimethyl-. (a) Chemical...chemical substance identified as 1H-pyrazole, 3,4-dimethyl- (PMN...

  6. 1H and 13C Solid-state NMR of Gossypium barbadense (Pima) Cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The interaction of water with cellulose and its influence on the nuclear spin dynamics in G. barbadense (Pima) cotton were investigated by 1H and 13C solid-state NMR techniques. 1H spin diffusion results from a Goldman-Shen experiment indicate that the water is multilayered. 1H MAS experiments pro...

  7. Infrared and 1H NMR structural study of 3-tropane, 3-granatane and 3-bicyclo(3.2.1)octane epimeric amino acids

    NASA Astrophysics Data System (ADS)

    Bellanato, J.; Avendaño, C.; Ballesteros, P.; de la Cuesta, E.; Santos, E.; Trigo, G. G.

    Five amino acids with known configuration: ?- and ?-3-amino-tropane- and 3-amino-bicyclo(3.2.1)octane-3-carboxylic acids and ? -3-amino-granatane-3-carboxylic acid have been studied by i.r. and 1H NMR spectroscopy. Both ?- and ?-zwitterion structures have been found for tropane and granatane amino acids. Equatorial and axial ammonium groups in ?-zwitterions can be distinguished by the number and frequencies of the ammonium deformation modes. A chair—boat conformation has been deduced for ?-3-amino-granatane-3-carboxylic acid.

  8. Novel Asymmetric Tetradentate Schiff Base Ligands Derived from 6-Metwia-Formyl4Hydroxy2-(1H)-Quinolone and Their Metal Complexes

    Microsoft Academic Search

    Adel A. A. Emara

    1999-01-01

    Novel asymmetric, tetradentate, dibasic Schiff base ligands were synthesized by the condensation of the half-unit Schiff base ligand 3-[o-aminophenyliminomethyl]-4-hydroxy-6-methyl-2-(1H)-quinolone with acetylacetone and salicylaldehyde. Cu(II), Ni(II), UO2 (VI) and Fe(III) complexes of both ligands were prepared using different salts in the case of Cu(II) and Ni(II) cations The structures of the ligands and the complexes were elucidated by chemical analyses, IR,

  9. Effect of IR laser on myoblasts: a proteomic study.

    PubMed

    Monici, Monica; Cialdai, Francesca; Ranaldi, Francesco; Paoli, Paolo; Boscaro, Francesca; Moneti, Gloriano; Caselli, Anna

    2013-06-01

    Laser therapy is used in physical medicine and rehabilitation to accelerate muscle recovery and in sports medicine to prevent damages produced by metabolic disturbances and inflammatory reactions after heavy exercise. The aim of this research was to get insight into possible benefits deriving from the application of an advanced IR laser system to counteract deficits of muscle energy metabolism and stimulate the recovery of hypotrophic tissue. We studied the effect of IR laser treatment on proliferation, differentiation, cytoskeleton organization and global protein expression in C2C12 myoblasts. We found that laser treatment induced a decrease in the cell proliferation rate without affecting cell viability, while leading to cytoskeletal rearrangement and expression of the early differentiation marker MyoD. The differential proteome analysis revealed the up-regulation and/or modulation of many proteins known to be involved in cell cycle regulation, cytoskeleton organization and differentiation. PMID:23364335

  10. 3-hydroxy-2(1H)-pyridinone chelating agents

    DOEpatents

    Raymond, K.N.; Xu, J.

    1997-04-29

    Disclosed is a series of improved metal chelating agents, which are highly effective upon both injection and oral administration; several of the most effective are of low toxicity. These chelating agents incorporate within their structure 1-hydroxy-2-pyridinone (1,2-HOPO) and 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy or oxo groups of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with its adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provides a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity. Also disclosed is a method of making the chelating agents and a method of producing a known compound, 3-hydroxy-1-alkyl-2(1H)pyridinone, used as a precursor to the chelating agent, safely and in large quantities. 2 figs.

  11. 3-hydroxy-2(1H)-pyridinone chelating agents

    DOEpatents

    Raymond, Kenneth N. (Berkeley, CA); Xu, Jide (Berkeley, CA)

    1997-01-01

    Disclosed is a series of improved metal chelating agents, which are highly effective upon both injection and oral administration; several of the most effective are of low toxicity. These chelating agents incorporate within their structure 1-hydroxy-2-pyridinone (1,2-HOPO) and 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy or oxo groups of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity of the hydroxypyridinones. In the metal complexes of said chelating agents, the amide protons form very strong hydrogen bonds with its adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provides a certain degree of lipophilicity to said 3,2-HOPO, increasing oral activity. Also disclosed is a method of making the chelating agents and a method of producing a known compound, 3-hydroxy-1-alkyl-2(1H)pyridinone, used as a precursor to the chelating agent, safely and in large quantities.

  12. 1H NMR Study of Water Adsorbed on Carbon Powders

    NASA Astrophysics Data System (ADS)

    Yu, I.; Lee, M.

    1H NMR relaxation measurements are performed for H 2O molecules adsorbed on the surface of carbon powders. Spin-lattice relaxation time T1 shows a minimum at T ˜ 185 K, where fast decrease in spin-spin relaxation time T2 occurs, and this corresponds to the slowing of intramolecular rotational motions. The T2 shows a maximum at a higher temperature, T ? 250 K. At the temperature where the T2 maximum occurs, the spin-lattice relaxation time in the rotating frame, T1?, also shows a maximum. The Carr-Purcell-Meiboom-Gill and stimulated echo measurements indicate the presence of nonconventional diffusion effects. These anomalies are interpreted as originating from the restricted diffusion of H 2O on the surface of carbon particles with the size of restriction about 20 Å, the diffusion constant equal to (6 ± 2) × 10 -12 cm 2/s, and a field gradient of (4 ± 1.5) × 10 5 Oe/cm, measured at room temperature.

  13. 7 CFR 792.20 - Reporting discharged debts to IRS.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Reporting discharged debts to IRS. 792.20 Section 792.20 Agriculture ...PROCEDURES § 792.20 Reporting discharged debts to IRS. (a) In accordance with IRS regulations, FSA may report to IRS as...

  14. 7 CFR 792.20 - Reporting discharged debts to IRS.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Reporting discharged debts to IRS. 792.20 Section 792.20 Agriculture ...PROCEDURES § 792.20 Reporting discharged debts to IRS. (a) In accordance with IRS regulations, FSA may report to IRS as...

  15. 7 CFR 1403.19 - Reporting discharged debts to IRS.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Reporting discharged debts to IRS. 1403.19 Section 1403.19 Agriculture...PROCEDURES § 1403.19 Reporting discharged debts to IRS. (a) In accordance with IRS regulations, CCC may report to IRS as...

  16. 7 CFR 1403.19 - Reporting discharged debts to IRS.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Reporting discharged debts to IRS. 1403.19 Section 1403.19 Agriculture...PROCEDURES § 1403.19 Reporting discharged debts to IRS. (a) In accordance with IRS regulations, CCC may report to IRS as...

  17. 7 CFR 792.20 - Reporting discharged debts to IRS.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Reporting discharged debts to IRS. 792.20 Section 792.20 Agriculture ...PROCEDURES § 792.20 Reporting discharged debts to IRS. (a) In accordance with IRS regulations, FSA may report to IRS as...

  18. 7 CFR 792.20 - Reporting discharged debts to IRS.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Reporting discharged debts to IRS. 792.20 Section 792.20 Agriculture ...PROCEDURES § 792.20 Reporting discharged debts to IRS. (a) In accordance with IRS regulations, FSA may report to IRS as...

  19. 7 CFR 1403.19 - Reporting discharged debts to IRS.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Reporting discharged debts to IRS. 1403.19 Section 1403.19 Agriculture...PROCEDURES § 1403.19 Reporting discharged debts to IRS. (a) In accordance with IRS regulations, CCC may report to IRS as...

  20. 7 CFR 1403.19 - Reporting discharged debts to IRS.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Reporting discharged debts to IRS. 1403.19 Section 1403.19 Agriculture...PROCEDURES § 1403.19 Reporting discharged debts to IRS. (a) In accordance with IRS regulations, CCC may report to IRS as...

  1. 7 CFR 792.20 - Reporting discharged debts to IRS.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Reporting discharged debts to IRS. 792.20 Section 792.20 Agriculture ...PROCEDURES § 792.20 Reporting discharged debts to IRS. (a) In accordance with IRS regulations, FSA may report to IRS as...

  2. 7 CFR 1403.19 - Reporting discharged debts to IRS.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Reporting discharged debts to IRS. 1403.19 Section 1403.19 Agriculture...PROCEDURES § 1403.19 Reporting discharged debts to IRS. (a) In accordance with IRS regulations, CCC may report to IRS as...

  3. Strong-Field Physics with Mid-IR Fields

    NASA Astrophysics Data System (ADS)

    Wolter, Benjamin; Pullen, Michael G.; Baudisch, Matthias; Sclafani, Michele; Hemmer, Michaël; Senftleben, Arne; Schröter, Claus Dieter; Ullrich, Joachim; Moshammer, Robert; Biegert, Jens

    2015-04-01

    Strong-field physics is currently experiencing a shift towards the use of mid-IR driving wavelengths. This is because they permit conducting experiments unambiguously in the quasistatic regime and enable exploiting the effects related to ponderomotive scaling of electron recollisions. Initial measurements taken in the mid-IR immediately led to a deeper understanding of photoionization and allowed a discrimination among different theoretical models. Ponderomotive scaling of rescattering has enabled new avenues towards time-resolved probing of molecular structure. Essential for this paradigm shift was the convergence of two experimental tools: (1) intense mid-IR sources that can create high-energy photons and electrons while operating within the quasistatic regime and (2) detection systems that can detect the generated high-energy particles and image the entire momentum space of the interaction in full coincidence. Here, we present a unique combination of these two essential ingredients, namely, a 160-kHz mid-IR source and a reaction microscope detection system, to present an experimental methodology that provides an unprecedented three-dimensional view of strong-field interactions. The system is capable of generating and detecting electron energies that span a 6 order of magnitude dynamic range. We demonstrate the versatility of the system by investigating electron recollisions, the core process that drives strong-field phenomena, at both low (meV) and high (hundreds of eV) energies. The low-energy region is used to investigate recently discovered low-energy structures, while the high-energy electrons are used to probe atomic structure via laser-induced electron diffraction. Moreover, we present, for the first time, the correlated momentum distribution of electrons from nonsequential double ionization driven by mid-IR pulses.

  4. The dual role of borohydride depending on reaction temperature: synthesis of iridium and iridium oxide.

    PubMed

    Chakrapani, Kalapu; Sampath, S

    2015-05-28

    Temperature dependent reaction products are observed when borohydride is present in aqueous solutions containing Ir(3+). At temperatures of 40 °C and above, metallic iridium is formed while under ambient conditions of 25 °C, borohydride results in an alkaline environment that helps in hydrolyzing the precursor to form IrO2. The Ir foams and IrO2 are subsequently used to study their catalytic properties. PMID:25978128

  5. Polynorbornene as a low loss matrix material for IR metamaterial applications.

    SciTech Connect

    Arrington, Christian Lew; Sinclair, Michael B.; Ginn, James Cleveland, III; Lee, Yun-Ju; Sanchez, Andrea E.; Clem, Paul Gilbert; Hines, Paul; Dirk, Shawn M.; Rasberry, Roger D.

    2010-11-01

    Novel low loss photopatternable matrix materials for IR metamaterial applications were synthesized using the ring opening metathesis polymerization reaction (ROMP) of norbornene followed by a partial hydrogenation to remove most of the IR absorbing olefin groups which absorb in the 8-12 {micro}m range. Photopatterning was achieved via crosslinking of the remaining olefin groups with alpha, omega-dithiols via the thiol-ene coupling reaction. Since ROMP is a living polymerization the molecular weight of the polymer can be controlled simply by varying the ratio of catalyst to monomer. In order to determine the optimum photopattenable IR matrix material we varied the amount of olefin remaining after the partial hydrogenation. Hydrogenation was accomplished using tosyl hydrazide. The degree of hydrogenation can be controlled by altering the reaction time or reaction stoichiometry and the by-products can be easily removed during workup by precipitation into ethanol. Several polymers have been prepared using this reduction scheme including two polymers which had 54% and 68% olefin remaining. Free standing films (approx. 12 {micro}m) were prepared from the 68% olefin material using draw-down technique and subsequently irradiated with a UV lamp (365 nm) for thirty minutes to induce crosslinking via thiol-ene reaction. After crosslinking, the olefin IR-absorption band disappeared and the Tg of the matrix material increased; both desirable properties for IR metamaterial applications. The polymer system has inherent photopatternable behavior primarily because of solubility differences between the pre-polymer and cross-linked matrix. Photopatterned structures using the 54% as well as the 68% olefin material were easily obtained. The synthesis, processing, and IR absorption data and the ramifications to dielectric metamaterials will be discussed.

  6. A study of the physico-chemical properties of 1,3,5-trihydroxy-1,3,5-triazin-2,4,6[1 H,3 H,5 H]-trione

    NASA Astrophysics Data System (ADS)

    Taka?, M. Jadrijevi?-Mladar; Kos, I.; Biruš, M.; Butula, I.; Gabri?evi?, M.

    2006-01-01

    Acetyl ( Ia) and pivaloyl ( Ib) triesters of the 1 N,3 N,5 N-trihydroxy-1,3,5-triazin-2,4,6[1 H,3 H,5 H]-trione ( I) were synthesised. The spectrophotometric and potentiometric investigation of I revealed a weak acidic properties of triprotonic acid (p Ka1=5.23, p Ka2=6.32, and p Ka3=7.93). The MS and TGA analyses of I indicated on hydroxyisocyanate as possible degradation product. The chelating ability of I with Fe(III)-ion was preliminary explored. IR measurements of aqueous solutions of I in the presence of Fe(III) ion showed the possible chelating ability of all hydroxamic moieties. The chemical structures and properties of investigated compounds were derived from the results of IR, 1H and 13C NMR, UV and MS spectrometric data, as well as thermogravimetric and potentiometric analysis.

  7. IR-IR-UV hole-burning: conformation specific IR spectra in the face of UV spectral overlap.

    PubMed

    Shubert, V Alvin; Zwier, Timothy S

    2007-12-27

    A new technique, IR-IR-UV hole-burning, is reported for obtaining conformation specific IR spectra when the electronic spectra are too closely overlapped to obtain clean spectra free from interference from other conformations via standard ion dip or fluorescence dip methods. The 4'-aminobenzo-15-crown-5 ether-(HDO) complex is used as an example, on which the method was applied to prove the presence of two conformations having overlapped electronic spectra and to assign IR transitions belonging to the same conformation. PMID:18047306

  8. [Charge control and IR analysis of amine on diarylide yellow pigment PY14].

    PubMed

    Li, Lu-hai; Zhang, Shu-fen; Yang, Jin-zong; Zou, Jing; Zhao, Qiang

    2005-10-01

    To study the reaction of amine with dairylide yellow pigment (PY14) used in electrophoretic display, especially the reaction mechanism between polyisobutylene imide (PIBI) and PY14, some amines were selected to react with PY14. At the same time, tetraethylene pentamine was treated with HCl. The zeta potential and IR of the above products were tested. Based on the zeta potential and IR frequency, the charge control intensities of different amines on PY14 were compared, and it is confirmed that the reaction of PY14 with amines is Lewis reaction, the charge control of secondary and primary amines with less steric obstacle is stronger. The PY14 zeta potential value reverse is due to the adsorption of bigger reverse ion. PMID:16395888

  9. DFT, FT-Raman, FT-IR, liquid and solid state NMR studies of 2,6-dimethoxyphenylboronic acid

    Microsoft Academic Search

    Özgür Alver; Cemal Parlak

    2010-01-01

    Possible stable forms and molecular structures of 2,6-dimethoxyphenylboronic acid (2,6-dmpba) were studied experimentally and theoretically using FT-IR, Raman, liquid–solid state NMR and XRD spectroscopic methods. FT-IR and Raman spectra were recorded in the region of 4000–200cm?1. 13C cross-polarization magic-angle spinning NMR and liquid phase 1H, 13C and HETCOR NMR spectra of 2,6-dmpba ((CH3O)2C6H3B(OH)2) were reported. The optimized geometric structures concerning

  10. Kinetics, stoichiometry, morphology, and current drive capabilities of Ir-based silicides

    SciTech Connect

    Larrieu, G.; Dubois, E.; Wallart, X.; Katcki, J. [Institut d'Electronique de Microelectronique et de Nanotechnologie, IEMN/ISEN UMR CNRS 8520, Avenue Poincare, Cite Scientifique, 59652 Villeneuve d'Ascq Cedex (France); Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw (Poland)

    2007-11-01

    A detailed study of the formation of iridium silicide obtained by ultrahigh vacuum annealing and atmospheric rapid thermal processing is proposed using x-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and electrical characterizations. Using XPS analysis, the stoichiometry of each silicide phase (IrSi, IrSi{sub 1.6}) is identified. A model based on the variation of the measured intensity of the Ir 4f spectra is used to obtain the kinetic coefficients of reaction of Ir silicidation (E{sub A}=2.48 eV, D{sub 0}=9 cm{sup 2}/s). TEM cross sections indicate that the roughness of the silicide/silicon interface increases with temperature. Lastly, electrical characteristics are used to identify the optimum annealing temperature to obtain an iridium silicide contact with the lowest Schottky barrier height to holes.

  11. Multimetallic compounds containing cyclometalated Ir(III) units: Synthesis, structure, electrochemistry and photophysical properties

    Microsoft Academic Search

    Tanima Hajra; Jitendra K. Bera; Vadapalli Chandrasekhar

    2011-01-01

    The reaction of the cyclometalated IrIII dimer [{(ppy)2Ir}2(?-Cl)2] (ppyH=2-phenylpyridine) with silver triflate followed by a multidentate ligand [1,4-bis[3-(2-pyridyl)pyrazolylmethyl]benzene (bppb), 1,3,5-tri[3-(2-pyridyl)pyrazolylmethyl]-2,4,6-trimethylbenzene (tppb), 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz), 2-chloro-4,6-bis(dipyridin-2-ylamino)-1,3,5-triazine (cddt) or 2,4,6-tris(dipyridin-2-ylamino)-1,3,5-triazine (tdat)] afforded di- or trinuclear compounds: [{Ir(ppy)2}2(?-bppb)](OTf)2 (1), [{Ir(ppy)2}3(?-tppb)](OTf)3 (2), [{Ir(ppy)2}2(?-tptz-OH)](OTf) (3), [{Ir(ppy)2}2(?-cddt)](OTf)2 (4) and [{Ir(ppy)2}2(?-tdat)](OTf)2 (5). All of these compounds contain cationic metal cores with corresponding triflate counter anions. The molecular structures

  12. DIGITAL ORTHOPHOTOS FROM IRS - PRODUCTION AND UTILIZATION

    Microsoft Academic Search

    Dan Rosenholm; Daniel Åkerman

    The Sweden based GAF subsidiary Observation, Mapping and Monitoring AB (OM&M) has produced ortho-images based on IRS data on a routine basis since May 1997. The Indian IRS-1C and 1D satellites are the first real multi-resolution optical satellites available on the market. The most well known sensor on IRS-1C\\/1D is the PAN sensor, with 5.8 meter resolution and a scene

  13. Sensitivity-Enhanced Static 15N NMR of Solids by 1H Indirect Detection

    NASA Astrophysics Data System (ADS)

    Hong, Mei; Yamaguchi, Satoru

    2001-05-01

    A method for enhancing the sensitivity of 15N spectra of nonspinning solids through 1H indirect detection is introduced. By sampling the 1H signals in the windows of a pulsed spin-lock sequence, high-sensitivity 1H spectra can be obtained in two-dimensional (2D) spectra whose indirect dimension yields the 15N chemical shift pattern. By sacrificing the 1H chemical shift information, sensitivity gains of 1.8 to 2.5 for the 15N spectra were achieved experimentally. A similar sensitivity enhancement was also obtained for 2D 15N- 1H dipolar and 15N chemical shift correlation spectroscopy, by means of a 3D 1H/ 15N- 1H/ 15N correlation experiment. We demonstrate this technique, termed PRINS for proton indirectly detected nitrogen static NMR, on a crystalline model compound with long 1H T1? and on a 25-kDa protein with short 1H T1?. This 1H indirect detection approach should be useful for enhancing the sensitivity of 15N NMR of oriented membrane peptides. It can also be used to facilitate the empirical optimization of 15N-detected experiments where the inherent sensitivity of the sample is low.

  14. Regional neonatal brain absolute thermometry by 1H MRS.

    PubMed

    Bainbridge, Alan; Kendall, Giles S; De Vita, Enrico; Hagmann, Cornelia; Kapetanakis, Andrew; Cady, Ernest B; Robertson, Nicola J

    2013-04-01

    Therapeutic hypothermia is standard care for infants with moderate to severe encephalopathy. (1) H MRS thermometry (MRSt) measures regional brain absolute temperature using the temperature-dependent water chemical shift. This study evaluates the clinical feasibility of MRSt in human neonates, and correlates white matter (WM) and thalamus (Thal) MRSt with conventional rectal temperature (Trectal ) measurement. Fifty-six infants born at term underwent perinatal MRSt for suspected hypoxic-ischaemic brain injury and 33 infants born preterm had MRSt at a term-equivalent age; 56 of the 89 had Trectal measured after MRSt of either a Thal or posterior WM voxel, or both. MRSt used point-resolved spectroscopy (no water suppression; TR = 1370 ms; TE = 288 ms; 1.5 × 1.5 × 1.5 cm(3) Thal and 1.1 × 1.3 × 1.4 cm(3) WM voxels). Time domain data were phase and frequency corrected before summation and motion-corrupted data were excluded from further analysis using simple criteria [preprocessing + quality assurance (QA)]. Two published water temperature-dependence calibrations [both using cerebral creatine (Cr), choline (Cho) and N-acetylaspartate (Naa) as independent reference peaks] were compared. The temperature measurements derived from Cr, Cho and Naa were combined to give a single amplitude-weighted combination temperature (TAWC ). WM and Thal TAWC correlated linearly with Trectal (Thal slope, 0.82 ± 0.04, R(2) = 0.85, p < 0.05; WM slope, 0.95 ± 0.04, R(2) = 0.78, p < 0.05). Preprocessing + QA improved the correlation between WM TAWC and Trectal (R(2) increased from 0.27 to 0.78, p < 0.001). Both calibration datasets showed specific inconsistencies between the temperatures calculated using Cr, Cho and Naa reference peaks when applied to this neonatal dataset. Neonatal MRSt is clinically feasible. Preprocessing +?QA improved MRSt reliability in WM. The consideration of MRSt calibration internal biases is necessary before combining MRSt temperatures from multiple reference peaks to obtain TAWC. PMID:23074155

  15. Decreased Insulin Clearance in Individuals with Elevated 1-h Post-Load Plasma Glucose Levels

    PubMed Central

    Marini, Maria Adelaide; Frontoni, Simona; Succurro, Elena; Arturi, Franco; Fiorentino, Teresa Vanessa; Sciacqua, Angela; Hribal, Marta Letizia; Perticone, Francesco; Sesti, Giorgio

    2013-01-01

    Reduced insulin clearance has been shown to predict the development of type 2 diabetes. Recently, it has been suggested that plasma glucose concentrations ?8.6 mmol/l (155 mg/dl) at 1 h during an oral glucose tolerance test (OGTT) can identify individuals at high risk for type 2 diabetes among those who have normal glucose tolerance (NGT 1 h-high). The aim of this study was to examine whether NGT 1 h-high have a decrease in insulin clearance, as compared with NGT individuals with 1-h post-load glucose <8.6 mmol/l (l (155 mg/dl, NGT 1 h-low). To this end, 438 non-diabetic White individuals were subjected to OGTT and euglycemic-hyperinsulinemic clamp to evaluate insulin clearance and insulin sensitivity. As compared with NGT 1 h-low individuals, NGT 1 h-high had significantly higher 1-h and 2-h post-load plasma glucose and 2-h insulin levels as well as higher fasting glucose and insulin levels. NGT 1 h-high exhibited also a significant decrease in both insulin sensitivity (P<0.0001) and insulin clearance (P?=?0.006) after adjusting for age, gender, adiposity measures, and insulin sensitivity. The differences in insulin clearance remained significant after adjustment for fasting glucose (P?=?0.02) in addition to gender, age, and BMI. In univariate analyses adjusted for gender and age, insulin clearance was inversely correlated with body weight, body mass index, waist, fat mass, 1-h and 2-h post-load glucose levels, fasting, 1-h and 2-h post-load insulin levels, and insulin-stimulated glucose disposal. In conclusion, our data show that NGT 1 h-high have a reduction in insulin clearance as compared with NGT 1 h-low individuals; this suggests that impaired insulin clearance may contribute to sustained fasting and post-meal hyperinsulinemia. PMID:24194886

  16. Magnetorheological finishing of IR materials

    NASA Astrophysics Data System (ADS)

    Jacobs, Stephen D.; Yang, Fuqian; Fess, Edward M.; Feingold, J. B.; Gillman, Birgit E.; Kordonski, William I.; Edwards, Harold; Golini, Donald

    1997-11-01

    Magnetorheological finishing (MRF) is a subaperture lap, deterministic process developed at the Center for Optics Manufacturing. MRF can remove subsurface damage from an optical component while correcting figure errors and smoothing small scale microroughness. The 'standard' magnetorheological fluid for finishing of optical glasses consists of magnetic carbonyl iron and nonmagnetic cerium oxide particles in water. This composition works well for a variety of soft and hard glass types, but it does not perform adequately for certain single crystal materials and polycrystalline compounds used in IR applications. In this paper, we describe modifications to MRF and finishing experiments for LiF, ZnSe, CaF2, AMTIR-1, ZnS, MgF2, sapphire, and CVD diamond.

  17. Towards hydrogen evolution initiated by LED light: 2-(1H-1,2,3-Triazol-4-yl)pyridine-containing polymers as photocatalyst.

    PubMed

    Happ, Bobby; Kübel, Joachim; Pfeffer, Michael G; Winter, Andreas; Hager, Martin D; Dietzek, Benjamin; Rau, Sven; Schubert, Ulrich S

    2015-04-01

    Two- and three-component polymethacrylates, featuring a 2-(1-substituted-1H-1,2,3-triazol-4-yl)pyridine-based metal complex as photosensitizer, a viologen-type electron mediator, and a triethylene glycol methyl ether as solubilizing part are synthesized by statistical reversible addition-fragmentation chain transfer (RAFT) radical polymerization allowing the construction of well-defined copolymers. Thereby, heteroleptic ruthenium(II) and iridium(III) complexes serve as charged photosensitizers. In hydrogen evolution experiments, as proof-of-concept, triethylamine is utilized as a sacrificial donor and colloidal platinum as hydrogen evolving catalyst. The macromolecules bearing heteroleptic iridium(III) complexes of the general formula [Ir(ppy)2 (trzpy)]PF6 (ppy: 2-phenylpyridine; trzpy: 2-(1-substituted-1H-1,2,3-triazol-4-yl)pyridine) and [Ir(btac)2 (trzpy)]PF6 (btac: 3-(2-benzothiazolyl)-7-(diethylamino)coumarin) are photocatalytically active producing molecular hydrogen in water upon illumination at 470 nm. By changing the cyclometalating ligand from ppy to btac, the photocatalytic performance of the copolymer as reflected in the turnover number increases by two orders of magnitude. PMID:25656046

  18. Theoretical and experimental IR, Raman and NMR spectra in studying the electronic structure of 2-nitrobenzoates

    NASA Astrophysics Data System (ADS)

    ?wis?ocka, R.; Samsonowicz, M.; Regulska, E.; Lewandowski, W.

    2007-05-01

    The influence of lithium, sodium, potassium, rubidium and cesium on the electronic system of the 2-nitrobenzoic acid (2-NBA) was studied. Optimized geometrical structures of studied compounds were calculated by HF, B3PW91, B3LYP methods using 6-311++G ?? basis set. The theoretical IR and NMR spectra were obtained. The vibrational (FT-IR, FT-Raman) and NMR ( 1H and 13C) spectra for 2-nitrobenzoic acid salts of alkali metals were also recorded. The assignment of vibrational spectra was done. Characteristic shifts of band wavenumbers and changes in band intensities along the metal series were observed. Good correlation between the wavenumbers of the vibrational bands in the IR and Raman spectra for 2-nitrobenzoates (2-NB) and ionic potential, electronegativity, atomic mass and affinity of metals were found. The chemical shifts of protons and carbons ( 1H, 13C NMR) in the series of studied alkali metal 2-nitrobenzoates were observed too. The calculated parameters were compared to experimental characteristic of studied compounds.

  19. 3D 15N/15N/1H chemical shift correlation experiment utilizing an RFDR-based 1H/1H mixing period at 100 kHz MAS

    NASA Astrophysics Data System (ADS)

    Nishiyama, Yusuke; Malon, Michal; Ishii, Yuji; Ramamoorthy, Ayyalusamy

    2014-07-01

    Homonuclear correlation NMR experiments are commonly used in the high-resolution structural studies of proteins. While 13C/13C chemical shift correlation experiments utilizing dipolar recoupling techniques are fully utilized under MAS, correlation of the chemical shifts of 15N nuclei in proteins has been a challenge. Previous studies have shown that the negligible 15N-15N dipolar coupling in peptides or proteins necessitates the use of a very long mixing time (typically several seconds) for effective spin diffusion to occur and considerably slows down a 15N/15N correlation experiment. In this study, we show that the use of mixing proton magnetization, instead of 15N, via the recoupled 1H-1H dipolar couplings enable faster 15N/15N correlation. In addition, the use of proton-detection under ultrafast MAS overcomes the sensitivity loss due to multiple magnetization transfer (between 1H and 15N nuclei) steps. In fact, less than 300 nL (?1.1 micromole quantity) sample is sufficient to acquire the 3D spectrum within 5 h. Our results also demonstrate that a 3D 15N/15N/1H experiment can render higher resolution spectra that will be useful in the structural studies of proteins at ultrafast MAS frequencies. 3D 15N/15N/1H and 2D radio frequency-driven dipolar recoupling (RFDR)-based 1H/1H experimental results obtained from a powder sample of N-acetyla-L-15N-valyl-L-15N-leucine at 70 and 100 kHz MAS frequencies are presented.

  20. Nucleophilic Substitution of Oxazino-/Oxazolino-/Benzoxazin- [3,2-b]indazoles: An Effective Route to 1 H-Indazolones

    PubMed Central

    Donald, Michael B.; Conrad, Wayne E.; Oakdale, James S.; Butler, Jeffrey D.; Haddadin, Makhluf J.; Kurth, Mark J.

    2011-01-01

    A variety of nucleophiles – thiolates, alkoxides, amines, iodide, and cyanide – react with oxazino-, oxazolino-, and benzoxazin[3,2-b]indazoles under microwave conditions to yield a diverse set of 2-substituted 1 H-indazolones. The synthetic utility of these indazoles is further demonstrated by ANRORC (Addition of the Nucleophile, Ring Opening, and Ring Closure) reactions to yield isomeric pyrazoloindazolones by a process wherein iodide acts first as a nucleophile and subsequently as a leaving group. PMID:20438102

  1. Reaction mechanisms of Li(0.30)La(0.57)TiO3 powder with ambient air: H+/Li+ exchange with water and Li2CO3 formation.

    PubMed

    Boulant, Anthony; Bardeau, Jean Francois; Jouanneaux, Alain; Emery, Joël; Buzare, Jean-Yves; Bohnke, Odile

    2010-04-28

    The proton/lithium exchange property of the lithium lanthanum titanate Li(0.30)La(0.57)TiO(3) (named LLTO) is shown to occur at room temperature under ambient air. The (1)H and (7)Li MAS NMR, TGA analysis and IR spectroscopy techniques are used to probe reaction mechanisms. XRPD analysis gives evidence of the topotactic character of this exchange reaction. As for exchange in aqueous solution, it is shown that Li(0.30)La(0.57)TiO(3) is able to dissociate water on the grain surface and then to exchange H(+) for Li(+) into the perovskite structure. Lithium hydroxide is then formed on the grain surface and afterwards reacts with CO(2) contained in air to form Li(2)CO(3). It is shown that this mechanism is reversible. When the aged sample (aging in air for 5 months at room temperature) is annealed at 400 degrees C for two hours, the initial LLTO sample is totally recovered, a mass loss is observed and the carbonate signal in IR spectra disappears, demonstrating the reversibility of the carbonation reaction process. PMID:20372722

  2. Monitoring bound HA1(H1N1) and HA1(H5N1) on freely suspended graphene over plasmonic platforms with infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Banerjee, Amrita; Chakraborty, Sumit; Altan-Bonnet, Nihal; Grebel, Haim

    2013-09-01

    Infrared (IR) spectroscopy provides fingerprinting of the energy and orientation of molecular bonds. The IR signals are generally weak and require amplification. Here we present a new plasmonic platform, made of freely suspended graphene, which was coating periodic metal structures. Only monolayer thick films were needed for a fast signal recording. We demonstrated unique IR absorption signals of bound proteins: these were the hemagglutinin area (HA1) of swine influenza (H1N1) and the avian influenza (H5N1) viruses bound to their respective tri-saccharides ligand receptors. The simplicity and sensitivity of such approach may find applications in fast monitoring of binding events.

  3. Chemical Reactions

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2009-05-01

    We don't often stop to think about it, but underlying many of our everyday activities are chemical reactions. From the cooking of an egg to the growth of a child, chemical reactions make things happen. Although many of the reactions that support our lives

  4. 1H-NMR, dielectric and calorimetric studies of molecular motions in m-nitroaniline crystal

    NASA Astrophysics Data System (ADS)

    Szostak, M. Magdalena; Wójcik, Gra?yna; Gallier, Jean; Bertault, Marcel; Freundlich, Piotr; Ko?odziej, Hubert A.

    1998-04-01

    Spin-lattice relaxation time, T1, spin-lattice relaxation time in the rotating frame, T1 ?, and the second moment of the resonance line measurements at 80 MHz and over the 190-380 K temperature range are reported for protons in the optically nonlinear material m-nitroaniline ( m-NA). T1 has also been measured for samples irradiated by low energy and low intensity radiation. The real and imaginary parts of electric permittivity as well as tan? ? have been recorded in the 80-380 K temperature range at frequencies ranging from 100 Hz to 1.0 MHz. DSC measurements have been performed in the 110-387 K temperature range. Two phase transitions have been found: A glassy to rotative transition at 160 K and a plastic to plastic transformation at 365 K. The main feature of the m-NA crystal is that its plasticity continues to grow as the temperature increases. The reorientations of phenyl rings, the -NH 2 group proton 180° jumps, the lattice distortions caused by anisotropic thermal expansion and the cooperative reorientations of big molecular aggregates are thought to be the reasons for phase transitions and for the subsequent intermolecular charge transfer. The results are discussed with respect to optical second harmonic generation and near-IR photochemical reaction found in the m-NA crystal.

  5. The slowdown of fast proton exchanges and the 1 h and 1 h- 14 n NMR spectra of hydrazine and its methyl derivatives

    Microsoft Academic Search

    N. G. Yunda; G. V. Lagodzinskaya; G. B. Manelis

    1975-01-01

    1.A method was proposed for slowing down rapid proton exchanges in hydrazine and its derivatives.2.The parameters of the1H and1H-14N NMR spectra of hydrazine, monomethylhydrazine, and nonsymmetrical dimethylhydrazine, thoroughly freed of ions that catalyze proton exchanges, were determined.3.Proton exchanges in nonsymmetrical dimethylhydrazine, hydrazine, and monomethylhydrazine become slow in the NMR time scale at a hydrozonium ion concentration of ~10-5, 10-8, and

  6. Unique Backbone-Water Interaction Detected in Sphingomyelin Bilayers with 1H/31P and 1H/13C HETCOR MAS NMR Spectroscopy

    PubMed Central

    Holland, Gregory P.; Alam, Todd M.

    2008-01-01

    Two-dimensional 1H/31P dipolar heteronuclear correlation (HETCOR) magic-angle spinning nuclear magnetic resonance (NMR) is used to investigate the correlation of the lipid headgroup with various intra- and intermolecular proton environments. Cross-polarization NMR techniques involving 31P have not been previously pursued to a great extent in lipid bilayers due to the long 1H-31P distances and high degree of headgroup mobility that averages the dipolar coupling in the liquid crystalline phase. The results presented herein show that this approach is very promising and yields information not readily available with other experimental methods. Of particular interest is the detection of a unique lipid backbone-water intermolecular interaction in egg sphingomyelin (SM) that is not observed in lipids with glycerol backbones like phosphatidylcholines. This backbone-water interaction in SM is probed when a mixing period allowing magnetization exchange between different 1H environments via the nuclear Overhauser effect (NOE) is included in the NMR pulse sequence. The molecular information provided by these 1H/31P dipolar HETCOR experiments with NOE mixing differ from those previously obtained by conventional NOE spectroscopy and heteronuclear NOE spectroscopy NMR experiments. In addition, two-dimensional 1H/13C INEPT HETCOR experiments with NOE mixing support the 1H/31P dipolar HETCOR results and confirm the presence of a H2O environment that has nonvanishing dipolar interactions with the SM backbone. PMID:18390621

  7. 1H, 13C and 31P MAS NMR studies of lyophilized brain tumors

    Microsoft Academic Search

    R. Marsza?ek; M. Pisklak; D. Horszty?ski; I. Wawer

    2010-01-01

    1H, 13C and 31P magic angle spinning magnetic resonance spectra (MAS NMR) of lyophilized brain tissue specimens were recorded. Among the 35 cases of brain tumors there were 24 glioblastomas, seven meningiomas and a few other types. 1H NMR measurements were performed with a MAS speed of 33kHz. The intense CH3, CH2 and CH? peaks in the 1H spectrum result

  8. Your FAFSA and the IRS Data Retrieval Tool What is the IRS Data Retrieval Tool?

    E-print Network

    Moore, Paul A.

    Your FAFSA and the IRS Data Retrieval Tool What is the IRS Data Retrieval Tool? The U.S. Department the completion of the FAFSA application. The IRS Data Retrieval tool allows FAFSA applicants and parents, it can be transferred to the FAFSA application. What are the benefits of using the DRT? Eligible

  9. Electronic [UV-Visible] and vibrational [FT-IR, FT-Raman] investigation and NMR-mass spectroscopic analysis of terephthalic acid using quantum Gaussian calculations

    NASA Astrophysics Data System (ADS)

    Karthikeyan, N.; Joseph Prince, J.; Ramalingam, S.; Periandy, S.

    2015-03-01

    In this research work, the vibrational IR, polarization Raman, NMR and mass spectra of terephthalic acid (TA) were recorded. The observed fundamental peaks (IR, Raman) were assigned according to their distinctiveness region. The hybrid computational calculations were carried out for calculating geometrical and vibrational parameters by DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The molecular mass spectral data related to base molecule and substitutional group of the compound was analyzed. The modification of the chemical property by the reaction mechanism of the injection of dicarboxylic group in the base molecule was investigated. The 13C and 1H NMR spectra were simulated by using the gauge independent atomic orbital (GIAO) method and the absolute chemical shifts related to TMS were compared with experimental spectra. The study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by hybrid Gaussian calculation methods. The orbital energies of different levels of HOMO and LUMO were calculated and the molecular orbital lobe overlapping showed the inter charge transformation between the base molecule and ligand group. From the frontier molecular orbitals (FMO), the possibility of electrophilic and nucleophilic hit also analyzed. The NLO activity of the title compound related to Polarizability and hyperpolarizability were also discussed. The present molecule was fragmented with respect to atomic mass and the mass variation depends on the substitutions have also been studied.

  10. Biradicals from benzoenyne-allenes. Application in the synthesis of 11H-benzo[b]fluoren-11-ols, 1H-cyclobut[a]indenes, and related compounds.

    PubMed

    Li, H; Zhang, H R; Petersen, J L; Wang, K K

    2001-10-01

    New synthetic pathways to 11H-benzo[b]fluoren-11-ols, 1H-cyclobut[a]indenes, and related compounds via biradicals generated from benzoenyne-allenes were developed. Treatment of the diacetylenic propargylic alcohols 13, derived from condensation between benzophenones and the lithium acetylide of 1-(2-ethynylphenyl)-2-phenylethyne, with thionyl chloride produced the 11-chloro-11H-benzo[b]fluorene 14 and, after hydrolysis, the corresponding 11H-benzo[b]fluoren-11-ols 15. The transformation involved a sequence of reactions, including a biradical-forming C2-C6 cyclization (Schmittel cyclization) reaction of the chlorinated benzoenyne-allene intermediates followed by an intramolecular radical-radical coupling to form the formal Diels-Alder adducts. Interestingly, in the case of the diacetylenic propargylic alcohol 26, obtained from dibenzosuberenone (25), an intramolecular [2 + 2] cycloaddition reaction of the chlorinated benzoenyne-allene intermediate occurred, furnishing the 1H-cyclobut[a]indene 27 exclusively. The dramatic change of the reaction pathway could be attributed to the emergence of a steric strain due to the nonbonded interactions with the chloro substituent along the pathway toward the formal Diels-Alder adduct 31. On the other hand, the non-chlorinated benzoenyne-allene, derived from prototropic isomerization of the diacetylenic hydrocarbon 60, underwent a formal Diels-Alder reaction to furnish the 11H-benzo[b]fluorene-type hydrocarbon 61 exclusively. PMID:11578218

  11. Synthesis, conformational, spectroscopic and chemical reactivity analysis of 2-cyano-3-(1H-pyrrol-2-yl)acrylohydrazide using experimental and quantum chemical approaches

    NASA Astrophysics Data System (ADS)

    Rawat, Poonam; Singh, R. N.

    2015-02-01

    This paper describes the synthesis, spectroscopic (1H and 13C NMR, UV-Visible, FT-IR and ESI Mass), conformational analysis, chemical reactivity and non-linear optical (NLO) properties of newly synthesized pyrrole derivative 2-cyano-3-(1H-pyrrol-2-yl)acrylohydrazide (2CPA) C8H8N4O using experimental and quantum chemical techniques. The presence of signal at ? 8.010 ppm due to vinyl proton as well as NH and NH2 protons signals at 11.054 and 2.499 ppm in experimental 1H NMR spectrum indicate that 2CPA contain sbnd CHdbnd CCNsbnd and sbnd NHsbnd NH2 frame. The combined experimental and theoretical symmetric (3194 cm-1) and asymmetric (3221 cm-1) stretching wavenumber analysis confirms free NH2 group in the solid phase FT-IR spectrum of the synthesized compound. The interaction energies of dimer formation using density functional theory (DFT) and Quantum theory of Atoms in Molecules (QTAIM) calculations are found to be 20.210, 19.683 kcal/mol, respectively. The maximum values of the electrophilic reactivity descriptors at C6 indicate that this site is more prone to nucleophilic attack and favoring the formation of heterocyclic derivatives. A natural bond orbital (NBOs) analysis has been carried out to investigate intramolecular charge transfer, conjugative and hyperconjugative interactions within molecule. The calculated first hyperpolarizability (?0) of 2CPA, indicates that investigated molecule will show non-linear optical response and might be used as non-linear optical (NLO) material.

  12. Concept based retrieval in classical IR systems

    Microsoft Academic Search

    H. P. Giger

    1988-01-01

    This paper describes some aspects of a project with the aim of developing a user-friendly interface to a classical Information Retrieval (IR) System in order to improve the effectiveness of retrieval. The character by character approach to IR has been abandoned in favor of an approach based on the meaning of both the queries and the texts containing the information

  13. IR-4 Ornamental Horticulture Program Trial Report

    E-print Network

    Lieth, J. Heinrich

    (s): 25901 (Cyclanilide), 25902 (Fascination), 25905 (MaxCel) and 25907 (ProVide) 1 Project Title: Efficacy and Phytotoxicity of Cyclanilide, Fascination, MaxCel and Provide for Increased Branching of Rose (Rosa `Kardinal') IR4 PR#: 25901 (Cyclanilide), 25902 (Fascination), 25905 (MaxCel) and 25907 (ProVide) IR4 Protocol

  14. A belief network model for IR

    Microsoft Academic Search

    Berthier A. Ribeiro-Neto; Richard R. Muntz

    1996-01-01

    We introduce a belief network model for IR which is derived from probabilistic considerations over a clearly defined sam- ple space. This model subsumes the classical models in IR and generalizes the inference network model of Turtle and Croft. Further, we show how to extend the model with infor- mation from other queries (which we call contexts) to yield improved

  15. A practical guide to IR windows

    Microsoft Academic Search

    Martin G. Robinson

    2003-01-01

    The Principal of using infrared (IR) viewing ports has been well established for many years. IR thermography is a proven, well tested, safe and efficient method of checking the serviceability of electrical components, and because it is a non-contact measurement it allows the test to be completed live, that is of course if the risk assessment score allows us to.

  16. Magnetic properties of Pt Ir nanowires

    NASA Astrophysics Data System (ADS)

    Sondón, Tristana; Saúl, Andrés; Guevara, Javier

    2007-09-01

    We study the magnetic properties of Pt 1- xIr x nanowires by using the ab-initiowien2k code, being 0 ? x ? 1. It has been established in the literature that Pt and Ir nanowires show very different behaviors if spin-orbit coupling (SOC) is considered or not in the calculation of their electronic structure. Pt nanowires have magnetic order only if SOC is considered, but Ir ones show the opposite behavior. In the case of Pt 1- xIr x nanowires and without considering SOC, the spin magnetic moment as a function of the Ir concentration ( ? vs. x) shows an almost linear behavior between the spin magnetic moments of pure wires. While ? Ir is relatively high, the ? Pt presents very low values. On the contrary, if SOC is taken into account, a very interesting behavior is found. While the pure wires have low average magnetic moment values, being zero for Ir one and 0.15 ? B for the Pt one, the curve ? vs. x shows a maximum at x = 1/2 of about 0.75 ? B. We discuss the influence of equilibrium bond length and hybridization effects on the electronic properties of Pt 1- xIr x nanowires.

  17. Synthesis, multiple interactions and spectroscopy analysis of ethyl-4-[(benzoyl)-hydrazonomethyl]-3,5-dimethyl-1H-pyrrole-2-carboxylate: Through experimental and quantum chemical approaches

    NASA Astrophysics Data System (ADS)

    Singh, R. N.; Kumar, Amit; Tiwari, R. K.; Rawat, Poonam

    2013-03-01

    The carboxaldehydes of pyrrole form important class of precursors for synthesis of acid hydrazide-hydrazones and their derivatives which show the various applications. A novel hydrazide-hydrazone of pyrrole: Ethyl-4-[(benzoyl)-hydrazonomethyl]-3,5-dimethyl-1H-pyrrole-2-carboxylate (3) has been synthesized by condensation of ethyl-4-formyl-3,5-dimetyl-1H-pyrrole-2-carboxylate and benzohydrazide. The product was characterized by spectroscopy methods (FT-IR, 1H NMR, UV-Vis and DART Mass) and quantum chemical calculations. The calculated thermodynamic parameters show that the formation of (3) is exothermic and spontaneous at room temperature. The local electronic descriptors analysis and molecular electrostatic potential surface were used to predict the sites and nature of interactions which indicate the dimer formation through multiple interaction through Nsbnd H⋯O and C-H⋯O. The vibrational analysis shows red shifts in vNsbnd H and vCdbnd O as result of dimer formation. Topological and energetic parameters generated by AIM show the nature of interactions in dimer. The interaction energies of dimer formation using DFT and AIM calculations are found to be 14.19 and 15.19 kcal/mol respectively. Ellipticity analysis confirms the presence of resonance assisted heteronuclear H-bonding in dimer.

  18. Synthesis and oxidation of CpIrIII compounds: functionalization of a Cp methyl group.

    PubMed

    Park-Gehrke, Lisa S; Freudenthal, John; Kaminsky, Werner; Dipasquale, Antonio G; Mayer, James M

    2009-03-21

    [CpIrCl(2)](2) () and new CpIr(III)(L-L)X complexes (L-L = N-O or C-N chelating ligands; X = Cl, I, Me) have been prepared and their reactivity with two-electron chemical oxidants explored. Reaction of with PhI(OAc)(2) in wet solvents yields a new chloro-bridged dimer in which each of the Cp ligands has been singly acetoxylated to form [Cp(OAc)Ir(III)Cl(2)](2) () (Cp(OAc) = eta(5)-C(5)Me(4)CH(2)OAc). Complex and related carboxy- and alkoxy-functionalized Cp(OR) complexes can also be prepared from plus (PhIO)(n) and ROH. [Cp(OAc)Ir(III)Cl(2)](2) () and the methoxy analogue [Cp(OMe)Ir(III)Cl(2)](2) () have been structurally characterized. Treatment of [CpIrCl(2)](2) () with 2-phenylpyridine yields CpIr(III)(ppy)Cl () (ppy = cyclometallated 2-phenylpyridyl) which is readily converted to its iodide and methyl analogues CpIr(III)(ppy)I and CpIr(III)(ppy)Me (). CpIr(III) complexes were also prepared with N-O chelating ligands derived from anthranilic acid (2-aminobenzoic acid) and alpha-aminoisobutyric acid (H(2)NCMe(2)COOH), ligands chosen to be relatively oxidation resistant. These complexes and were reacted with potential two-electron oxidants including PhI(OAc)(2), hexachlorocyclohexadienone (C(6)Cl(6)O), N-fluoro-2,4,6-trimethylpyridinium (Me(3)pyF(+)), [Me(3)O]BF(4) and MeOTf (OTf = triflate, CF(3)SO(3)). Iridium(V) complexes were not observed or implicated in these reactions, despite the similarity of the potential products to known CpIr(V) species. The carbon electrophiles [Me(3)O]BF(4) and MeOTf appear to react preferentially at the N-O ligands, to give methyl esters in some cases. Overall, the results indicate that Cp is not inert under oxidizing conditions and is therefore not a good supporting ligand for oxidizing organometallic complexes. PMID:19259567

  19. Influence of the metal (Al, Cr, and Co) and substituents of the porphyrin in controlling reactions involved in copolymerization of propylene oxide and carbon dioxide by porphyrin metal(III) complexes. 3. Cobalt chemistry.

    PubMed

    Chatterjee, Chandrani; Chisholm, Malcolm H; El-Khaldy, Adnan; McIntosh, Ruaraidh D; Miller, Jeffrey T; Wu, Tianpin

    2013-04-15

    A series of cobalt(III) complexes LCoX, where L = 5,10,15,20-tetraphenylporphyrin (TPP), 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (TFPP), and 2,3,7,8,12,13,17,18-octaethylporphyirn (OEP) and X = Cl or acetate, has been investigated for homopolymerization of propylene oxide (PO) and copolymerization of PO and CO2 to yield polypropylene oxide (PPO) and polypropylene carbonate (PPC) or propylene carbonate (PC), respectively. These reactions were carried out both with and without the presence of a cocatalyst, namely, 4-dimethylaminopyridine (DMAP) or PPN(+)Cl(-) (bis(triphenylphosphine)iminium chloride). The PO/CO2 copolymerization process is notably faster than PO homopolymerization. With ionic PPN(+)Cl(-) cocatalyst the TPPCoOAc catalyst system grows two chains per Co center and the presence of excess [Cl(-)] facilitates formation of PC by two different backbiting mechanisms during copolymerization. Formation of PPC is dependent on both [Cl(-)] and the CO2 pressure employed (1-50 bar). TPPCoCl and PO react to form TPPCo(II) and ClCH2CH(Me)OH, while with DMAP, TPPCoCl yields TPPCo(DMAP)2(+)Cl(-). The reactions and their polymers and other products have been monitored by various methods including react-IR, FT-IR, GPC, ESI, MALDI TOF, EXAFS, and NMR ((1)H, (13)C{(1)H}) spectroscopy. Notable differences are seen in these reactions with previous studies of (porphyrin)M(III) complexes (M = Al, Cr) and of the (salen)M(III) complexes where M = Cr, Co. PMID:23556475

  20. Insulin receptor substrate (IRS)-2, not IRS-1, protects human neuroblastoma cells against apoptosis

    Microsoft Academic Search

    Bhumsoo Kim; Eva L. Feldman

    2009-01-01

    Insulin receptor substrates (IRS)-1 and -2 are major substrates of insulin and type I insulin-like growth factor (IGF-I) receptor\\u000a (IGF-IR) signaling. In this study, SH-EP human neuroblastoma cells are used as a model system to examine the differential\\u000a roles of IRS-1 and IRS-2 on glucose-mediated apoptosis. In the presence of high glucose, IRS-1 underwent caspase-mediated\\u000a degradation, followed by focal adhesion

  1. Organometallic 3-(1H-Benzimidazol-2-yl)-1H-pyrazolo[3,4-b]pyridines as Potential Anticancer Agents

    PubMed Central

    2011-01-01

    Six organometallic complexes of the general formula [MIICl(?6-p-cymene)(L)]Cl, where M = Ru (11a, 12a, 13a) or Os (11b, 12b, 13b) and L = 3-(1H-benzimidazol-2-yl)-1H-pyrazolo[3,4-b]pyridines (L1–L3) have been synthesized. The latter are known as potential cyclin-dependent kinase (Cdk) inhibitors. All compounds have been comprehensively characterized by elemental analysis, one- and two-dimensional NMR spectroscopy, UV–vis spectroscopy, ESI mass spectrometry, and X-ray crystallography (11b and 12b). The multistep synthesis of 3-(1H-benzimidazol-2-yl)-1H-pyrazolo[3,4-b]pyridines (L1–L3), which was reported by other researchers, has been modified by us essentially (e.g., the synthesis of 5-bromo-1H-pyrazolo[3,4-b]pyridine-3-carboxylic acid (3) via 5-bromo-3-methyl-1H-pyrazolo[3,4-b]pyridine (2); the synthesis of 1-methoxymethyl-2,3-diaminobenzene (5) by avoiding the use of unstable 2,3-diaminobenzyl alcohol; and the activation of 1H-pyrazolo[3,4-b]pyridine-3-carboxylic acids (1, 3) through the use of an inexpensive coupling reagent, N,N?-carbonyldiimidazole (CDI)). Stabilization of the 7b tautomer of methoxymethyl-substituted L3 by coordination to a metal(II) center, as well as the NMR spectroscopic characterization of two tautomers 7b-L3 and 4b?-L3 in a metal-free state are described. Structure–activity relationships with regard to cytotoxicity and cell cycle effects in human cancer cells, as well as Cdk inhibitory activity, are also reported. PMID:22032295

  2. Use of 1H/23Na and 1H/31P double frequency tuned birdcage coils to study in vivo carbon tetrachloride-induced hepatotoxicity in rats.

    PubMed

    Towner, R A; Janzen, E G; Chu, S C; Rath, A

    1992-01-01

    In vivo 1H and 23Na magnetic resonance imaging (MRI) and 31P magnetic resonance spectroscopy (MRS) techniques were used to study CCl4-induced acute hepatotoxicity in rats in situ. One or two hours following exposure to CCl4, a localized edematous region was detected in the liver by 1H MRI. The CCl4-induced edema was localized in a region surrounding the hepatic portal vein. With the use of a 23Na/1H double frequency tuned bird-cage imaging coil an increase in Na+ ion flux was also observed in the same region as the edematous region detected by 1H-MRI. Pretreatment with alpha-phenyl-tert-butyl nitrone (PBN), a free radical spin trap, 30 min prior to CCl4 exposure, was found to reduce the CCl4-induced edematous response in the liver observed in either 1H or 23Na-NMR images. Inhibition of the CCl4-induced edematous response in rat liver by PBN demonstrates that free radical intermediates, arising from the metabolism of CCl4, are possibly the key causal agents in the initiation of the edematous response. In addition, with the use of a 31P/1H double frequency tuned bird-cage imaging/spectroscopy coil, localized 31P spectra (ISIS) were obtained from the regions of CCl4-induced "tissue damage" observed in the 1H-MRI images. The most notable changes observed from the 31P spectra were an increase in inorganic phosphate (Pi) and a decrease in hepatocytosolic pH in the CCl4-treated rat livers in comparison to saline-treated control livers. PMID:1501538

  3. Predicted NO/sub 2/ ir chemiluminescence in the natural atmosphere. Technical report, February-May 1986

    SciTech Connect

    Adler-Golden, S.

    1986-05-13

    Results from the author's recent theoretical study of NO/sub 2/ ir chemiluminescence from the NO + 0 and NO + O/sub 3/ reactions are employed in a new upper atmospheric NO/sub 2/ ir radiance model. Predictions are made for altitude-dependent and column-integrated NO/sub 2/ chemiluminescent radiance in four vibrational bands, and comparison is made with previous model predictions.

  4. An in situ FT-IR study of CO hydrogenation over cerium oxide

    SciTech Connect

    Li, Can (Dalian Institute of Chemical Physics (China)); Maruya, Kenichi (Tokyo Institute of Technology (Japan)); Onishi, Takaharu (Tokyo Polytechnic College (Japan)); Domen, Kazunari

    1993-06-01

    The CO hydrogenation over cerium oxide was studied by using a closed circulating reaction system and in situ Fourier transform infrared spectroscopy (FT-IR) at 300-673 K. The major products of the CO-H[sub 2] reaction over cerium oxide were found to be olefins (C[sub 2][sup =]-C[sub 4][sup =]), CH[sub 4], CO[sub 2], and H[sub 2]O. IR bands due to surface oxygen-containing species such as formate, dioxymethylene, methoxy, and formyl were always detected during the CO-H[sub 2] reaction at 300-573 K over cerium oxide. No direct relationship between the surface oxygen-containing species and the production of hydrocarbons were found. The mechanism of CO hydrogenation on cerium oxide involving the surface redox was discussed. 14 refs., 8 figs.

  5. Sensory activity, chemical structure, and synthesis of Maillard generated bitter-tasting 1-oxo-2,3-dihydro-1H-indolizinium-6-olates.

    PubMed

    Frank, Oliver; Jezussek, Magnus; Hofmann, Thomas

    2003-04-23

    Thermal treatment of aqueous solutions of xylose, rhamnose, and l-alanine led to a rapid development of a bitter taste of the reaction mixture. To characterize the key compounds causing this bitter taste, the recently developed taste dilution analysis (TDA), which is based on the determination of the taste threshold of reaction products in serial dilutions of HPLC fractions, was performed to locate the most intense taste compounds in the complex mixture of Maillard reaction products. By application of this TDA, 26 fractions were obtained, among which seven fractions were evaluated with a high taste impact. LC/MS and NMR spectroscopy as well as synthetic experiments revealed the 1-oxo-2,3-dihydro-1H-indolizinium-6-olates 1-5 as the key compounds contributing the most to the intense bitter taste of the Maillard mixture. Calculation of the taste impact of these compounds based on a dose/activity relationship indicated that these five compounds already accounted for 56.8% of the overall bitterness of the Maillard mixture, thus demonstrating this class of 1-oxo-2,3-dihydro-1H-indolizinium-6-olates as the key bitter compounds. First synthetic studies on the relationship between the chemical structure and the human psychobiological activity of 1-oxo-2,3-dihydro-1H-indolizinium-6-olates revealed that substitution of the furan rings of 1 by 5-methylfuryl moieties (compounds 3-5) or by 5-(hydroxymethyl)furyl groups (compound 6) led to a significant increase of the bitter threshold. In contrast, the substitution of the oxygen atoms in the furan rings of 1 by sulfur atoms induced a significant decrease of the detection threshold of the 1-oxo-2,3-dihydro-1H-indolizinium-6-olate; for example, the thiophene derivative 7 showed the extraordinarily low bitter detection threshold of 6.3 x 10(-5) mmol/kg (water). PMID:12696959

  6. Identification of components of Brazilian honey by 1 H NMR and classification

    E-print Network

    Ferreira, Márcia M. C.

    Identification of components of Brazilian honey by 1 H NMR and classification of its botanical: Received 30 August 2011 Received in revised form 21 April 2012 Accepted 24 April 2012 Keywords: Honey 1 H squares e discriminant analysis a b s t r a c t The potential of NMR spectroscopy to differentiate honeys

  7. Practical aspects of 1H transverse paramagnetic relaxation enhancement measurements on macromolecules

    Microsoft Academic Search

    Junji Iwahara; Chun Tang; G. Marius Clore

    2007-01-01

    The use of 1H transverse paramagnetic relaxation enhancement (PRE) has seen a resurgence in recent years as method for providing long-range distance information for structural studies and as a probe of large amplitude motions and lowly populated transient intermediates in macromolecular association. In this paper we discuss various practical aspects pertaining to accurate measurement of PRE 1H transverse relaxation rates

  8. New proton radioactivities {sup 165,166,167}Ir and {sup 171}Au

    SciTech Connect

    Davids, C.N.; Blumenthal, D.J.; Brown, L.T.; Henderson, D.J.; Penttilae, H.T.; Seweryniak, D. [Argonne National Laboratory, Argonne, Illinois 60439 (United States)] [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Woods, P.J.; Davinson, T.; Irvine, R.J.; Page, R.D. [University of Edinburgh, Edinburgh (United Kingdom)] [University of Edinburgh, Edinburgh (United Kingdom); Batchelder, J.C. [Louisiana State University, Baton Rouge, Louisiana 70803 (United States)] [Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Bingham, C.R.; Zimmerman, B.E. [University of Tennessee, Knoxville, Tennessee 37996 (United States)] [University of Tennessee, Knoxville, Tennessee 37996 (United States); Bingham, C.R.; Toth, K.S. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Brown, L.T. [Vanderbilt University, Nashville, Tennessee 37235 (United States)] [Vanderbilt University, Nashville, Tennessee 37235 (United States); Busse, B.C. [Oregon State University, Corvallis, Oregon 97331 (United States)] [Oregon State University, Corvallis, Oregon 97331 (United States); Conticchio, L.F.; Penttilae, H.T.; Seweryniak, D.; Walters, W.B. [University of Maryland, College Park, Maryland 20742 (United States)] [University of Maryland, College Park, Maryland 20742 (United States); Freeman, S.J. [University of Manchester, Manchester (United Kingdom)] [University of Manchester, Manchester (United Kingdom)

    1997-05-01

    The new proton radioactivities {sup 165,166,167}Ir and {sup 171}Au have been observed. The Ir isotopes were produced {ital via} the {sup 92}Mo({sup 78}Kr,pxn){sup 165,166,167}Ir reactions at 357 and 384 MeV. {sup 171}Au was produced {ital via} the {sup 96}Ru({sup 78}Kr,p2n){sup 171}Au reaction at 389 MeV. The proton emitters were each identified by position, time, and energy correlations between the implantation of a residual nucleus into a double-sided silicon strip detector, the observation of a decay proton, and the subsequent observation of a decay alpha particle from the daughter nucleus ({sup 164,165,166}Os and {sup 170}Pt, respectively). Both {sup 166}Ir and {sup 167}Ir have proton-emitting ground and isomeric states, which also decay by alpha emission. The proton-decay rates have been reproduced by calculations using the WKB barrier penetration approximation and a low-seniority shell-model calculation of the spectroscopic factors. The alpha decays of the four nuclei are followed by chains of alpha decays, allowing the determination of single-particle orbital orderings. Mass information has also been obtained from the alpha-decay chains because a connection to a known mass can be obtained for one of the nuclei. Ground-state mass excesses are reported for {sup 151}Tm, {sup 154}Yb, {sup 155}Lu, {sup 158}Hf, {sup 159}Ta, {sup 162}W, {sup 163}Re, {sup 166}Os, {sup 167}Ir, and {sup 170}Pt. The mass excess for {sup 171m}Au is also given. Proton separation energies are also deduced for the odd-Z alpha daughter nuclei of the Ir proton emitters. {copyright} {ital 1997} {ital The American Physical Society}

  9. 4(1H)-pyridone and 4(1H)-quinolone derivatives as antimalarials with erythrocytic, exoerythrocytic, and transmission blocking activities.

    PubMed

    Monastyrskyi, Andrii; Kyle, Dennis E; Manetsch, Roman

    2014-01-01

    Infectious diseases are the second leading cause of deaths in the world with malaria being responsible for approximately the same amount of deaths as cancer in 2012. Despite the success in malaria prevention and control measures decreasing the disease mortality rate by 45% since 2000, the development of single-dose therapeutics with radical cure potential is required to completely eradicate this deadly condition. Targeting multiple stages of the malaria parasite is becoming a primary requirement for new candidates in antimalarial drug discovery and development. Recently, 4(1H)- pyridone, 4(1H)-quinolone, 1,2,3,4-tetrahydroacridone, and phenoxyethoxy-4(1H)-quinolone chemotypes have been shown to be antimalarials with blood stage activity, liver stage activity, and transmission blocking activity. Advancements in structure-activity relationship and structure-property relationship studies, biological evaluation in vitro and in vivo, as well as pharmacokinetics of the 4(1H)-pyridone and 4(1H)-quinolone chemotypes are discussed. PMID:25116582

  10. 4(1H)-Pyridone and 4(1H)-Quinolone Derivatives as Antimalarials with Erythrocytic, Exoerythrocytic, and Transmission Blocking Activities

    PubMed Central

    Monastyrskyi, Andrii; Kyle, Dennis E.; Manetsch, Roman

    2015-01-01

    Infectious diseases are the second leading cause of deaths in the world with malaria being responsible for approximately the same amount of deaths as cancer in 2012. Despite the success in malaria prevention and control measures decreasing the disease mortality rate by 45% since 2000, the development of single-dose therapeutics with radical cure potential is required to completely eradicate this deadly condition. Targeting multiple stages of the malaria parasite is becoming a primary requirement for new candidates in antimalarial drug discovery and development. Recently, 4(1H)-pyridone, 4(1H)-quinolone, 1,2,3,4-tetrahydroacridone, and phenoxyethoxy-4(1H)-quinolone chemotypes have been shown to be antimalarials with blood stage activity, liver stage activity, and transmission blocking activity. Advancements in structure-activity relationship and structure-property relationship studies, biological evaluation in vitro and in vivo, as well as pharmacokinetics of the 4(1H)-pyridone and 4(1H)-quinolone chemotypes will be discussed. PMID:25116582

  11. Irs2 and Irs4 synergize in non-LepRb neurons to control energy balance and glucose homeostasis.

    PubMed

    Sadagurski, Marianna; Dong, X Charlie; Myers, Martin G; White, Morris F

    2014-02-01

    Insulin receptor substrates (Irs1, 2, 3 and Irs4) mediate the actions of insulin/IGF1 signaling. They have similar structure, but distinctly regulate development, growth, and metabolic homeostasis. Irs2 contributes to central metabolic sensing, partially by acting in leptin receptor (LepRb)-expressing neurons. Although Irs4 is largely restricted to the hypothalamus, its contribution to metabolic regulation is unclear because Irs4-null mice barely distinguishable from controls. We postulated that Irs2 and Irs4 synergize and complement each other in the brain. To examine this possibility, we investigated the metabolism of whole body Irs4(-/y) mice that lacked Irs2 in the CNS (bIrs2(-/-)·Irs4(-/y)) or only in LepRb-neurons (Lepr (?Irs2) ·Irs4 (-/y) ). bIrs2(-/-)·Irs4(-/y) mice developed severe obesity and decreased energy expenditure, along with hyperglycemia and insulin resistance. Unexpectedly, the body weight and fed blood glucose levels of Lepr (?Irs2) ·Irs4 (-/y) mice were not different from Lepr (?Irs2) mice, suggesting that the functions of Irs2 and Irs4 converge upon neurons that are distinct from those expressing LepRb. PMID:24567904

  12. Flux growth of Yb(6.6)Ir(6)Sn(16) having mixed-valent ytterbium.

    PubMed

    Peter, Sebastian C; Subbarao, Udumula; Rayaprol, Sudhindra; Martin, Joshua B; Balasubramanian, Mahalingam; Malliakas, Christos D; Kanatzidis, Mercouri G

    2014-07-01

    The compound Yb6.6Ir6Sn16 was obtained as single crystals in high yield from the reaction of Yb with Ir and Sn run in excess indium. Single-crystal X-ray diffraction analysis shows that Yb6.6Ir6Sn16 crystallizes in the tetragonal space group P42/nmc with a = b = 9.7105(7) Å and c = 13.7183(11) Å. The crystal structure is composed of a [Ir6Sn16] polyanionic network with cages in which the Yb atoms are embedded. The Yb sublattice features extensive vacancies on one crystallographic site. Magnetic susceptibility measurements on single crystals indicate Curie-Weiss law behavior <100 K with no magnetic ordering down to 2 K. The magnetic moment within the linear region (<100 K) is 3.21 ?B/Yb, which is ?70% of the expected value for a free Yb(3+) ion suggesting the presence of mixed-valent ytterbium atoms. X-ray absorption near edge spectroscopy confirms that Yb6.6Ir6Sn16 exhibits mixed valence. Resistivity and heat capacity measurements for Yb6.6Ir6Sn16 indicate non-Fermi liquid metallic behavior. PMID:24921221

  13. Gallium nitride micromechanical resonators for IR detection

    NASA Astrophysics Data System (ADS)

    Rais-Zadeh, Mina

    2012-06-01

    This paper reports on a novel technology for low-noise un-cooled detection of infrared (IR) radiation using a combination of piezoelectric, pyroelectric, electrostrictive, and resonant effects. The architecture consists of a parallel array of high-Q gallium nitride (GaN) micro-mechanical resonators coated with an IR absorbing nanocomposite. The nanocomposite absorber converts the IR energy into heat with high efficiency. The generated heat causes a shift in frequency characteristics of the GaN resonators because of pyroelectric effect. IR detection is achieved by sensing the shift in the resonance frequency and amplitude of the exposed GaN resonator as compared to a reference resonator that is included in the array. This architecture offers improved signal to noise ratio compared with conventional pyroelectric detectors as the resonant effect reduces the background noise and improves sensitivity, enabling IR detection with NEDTs below 5 mK at room temperature. GaN is chosen as the resonant material as it possesses high pyroelectric, electrostrictive, and piezoelectric coefficients and can be grown on silicon substrates for low-cost batch fabrication. Measured results of a GaN IR detector prototype and a thin-film nanocomposite IR absorber are presented in this paper.

  14. Triglyceride-coated nanoparticles: skin toxicity and effect of UV/IR irradiation on them.

    PubMed

    Jebali, Ali; Kazemi, Bahram

    2013-09-01

    Triglyceride (TG) is an important compound on the skin, produced by sebaceous glands, and may change cytotoxicity of different nanoparticles. To date, there is no report about toxicity of nanoparticles coated with TG. On the other hand, the use of ultraviolet (UV) and infrared (IR) with nanoparticles changes nanoparticle cytotoxicity. The combination of nanoparticles with UV or IR is applicable, because it may be used for treatment or detection of local cancers, surface microbial infections and other skin diseases. In this study, different nanoparticles including titanium dioxide, zinc oxide, magnesium oxide, silver, gold, and TG-coated form of these nanoparticles, were added to suspensions of Balb/c skin cells, and then incubated for 24h at 37°C. Additionally, TG-coated nanoparticles were treated with UV and IR irradiation for 1h. Different methods were applied for evaluation of cytotoxicity, including 5-diphenyl-tetrazolium bromide assay, lactate dehydrogenase (LDH) assay, cell metabolic assay, ATP assay, and reactive oxygen species (ROS) generation assay. This research showed that TG-coated nanoparticles had less LDH release and ROS generation with higher cell viability, cell metabolic activity, and ATP level, compared with pristine nanoparticles. In contrast, the combination of UV and IR with TG-coated nanoparticles led to higher LDH release and ROS generation with less cell viability, cell metabolic activity, and ATP level, in comparison with pristine nanoparticles. Overall, pristine metal nanoparticles without irradiation had higher cytotoxicity than metal oxide nanoparticles. PMID:23743185

  15. Low-energy proton capture reactions

    NASA Astrophysics Data System (ADS)

    Lipoglavsek, M.; Cvetinovic, A.; Gajevic, J.; Likar, A.; Petrovic, T.; Vavpetic, P.

    2014-05-01

    An overview of experimental problems in measuring the cross sections for (p,?) and (p,n) reactions at low energies is given with a specific emphasis on electron screening in metallic targets. Thick target ?-ray and neutron yields are compared for Ni and NiO targets, V and VO2 targets and Mn and MnO targets. The 1H(7Li,?)4He reaction was studied in inverse kinematics with hydrogen loaded into Pd and PdAg alloy foils from gas phase. Based on these results, a new approach to electron screening in nuclear reactions is suggested.

  16. Low-energy proton capture reactions

    SciTech Connect

    Lipoglavsek, M.; Cvetinovic, A.; Gajevic, J.; Likar, A.; Vavpetic, P. [Jozef Stefan Institute, Jamova ulica 39, Ljubljana (Slovenia); Petrovic, T. [Jozef Stefan Institute, Jamova ulica 39, Ljubljana, Slovenia and Cosylab d.d., Teslova ulica 30, Ljubljana (Slovenia)

    2014-05-09

    An overview of experimental problems in measuring the cross sections for (p,?) and (p,n) reactions at low energies is given with a specific emphasis on electron screening in metallic targets. Thick target ?-ray and neutron yields are compared for Ni and NiO targets, V and VO{sub 2} targets and Mn and MnO targets. The {sup 1}H({sup 7}Li,?){sup 4}He reaction was studied in inverse kinematics with hydrogen loaded into Pd and PdAg alloy foils from gas phase. Based on these results, a new approach to electron screening in nuclear reactions is suggested.

  17. Understanding the Effect of Monomeric Iridium(III/IV) Aquo Complexes on the Photoelectrochemistry of IrOx·nH2O-Catalyzed Water-Splitting Systems.

    PubMed

    Zhao, Yixin; Vargas-Barbosa, Nella M; Strayer, Megan E; McCool, Nicholas S; Pandelia, Maria-Erini; Saunders, Timothy P; Swierk, John R; Callejas, Juan F; Jensen, Lasse; Mallouk, Thomas E

    2015-07-15

    Soluble, monomeric Ir(III/IV) complexes strongly affect the photoelectrochemical performance of IrOx·nH2O-catalyzed photoanodes for the oxygen evolution reaction (OER). The synthesis of IrOx·nH2O colloids by alkaline hydrolysis of Ir(III) or Ir(IV) salts proceeds through monomeric intermediates that were characterized using electrochemical and spectroscopic methods and modeled in TDDFT calculations. In air-saturated solutions, the monomers exist in a mixture of Ir(III) and Ir(IV) oxidation states, where the most likely formulations at pH 13 are [Ir(OH)5(H2O)](2-) and [Ir(OH)6](2-), respectively. These monomeric anions strongly adsorb onto IrOx·nH2O colloids but can be removed by precipitation of the colloids with isopropanol. The monomeric anions strongly adsorb onto TiO2, and they promote the adsorption of ligand-free IrOx·nH2O colloids onto mesoporous titania photoanodes. However, the reversible adsorption/desorption of electroactive monomers effectively short-circuits the photoanode redox cycle and thus dramatically degrades the photoelectrochemical performance of the cell. The growth of a dense TiO2 barrier layer prevents access of soluble monomeric anions to the interface between the oxide semiconductor and the electrode back contact (a fluorinated tin oxide transparent conductor) and leads to improved photoanode performance. Purified IrOx·nH2O colloids, which contain no adsorbed monomer, give improved performance at the same electrodes. These results explain earlier observations that IrOx·nH2O catalysts can dramatically degrade the performance of metal oxide photoanodes for the OER reaction. PMID:26106904

  18. Cerebral glutamine metabolism under hyperammonemia determined in vivo by localized 1H and 15N NMR spectroscopy

    PubMed Central

    Cudalbu, Cristina; Lanz, Bernard; Duarte, João MN; Morgenthaler, Florence D; Pilloud, Yves; Mlynárik, Vladimir; Gruetter, Rolf

    2012-01-01

    Brain glutamine synthetase (GS) is an integral part of the glutamate–glutamine cycle and occurs in the glial compartment. In vivo Magnetic Resonance Spectroscopy (MRS) allows noninvasive measurements of the concentrations and synthesis rates of metabolites. 15N MRS is an alternative approach to 13C MRS. Incorporation of labeled 15N from ammonia in cerebral glutamine allows to measure several metabolic reactions related to nitrogen metabolism, including the glutamate–glutamine cycle. To measure 15N incorporation into the position 5N of glutamine and position 2N of glutamate and glutamine, we developed a novel 15N pulse sequence to simultaneously detect, for the first time, [5-15N]Gln and [2-15N]Gln+Glu in vivo in the rat brain. In addition, we also measured for the first time in the same experiment localized 1H spectra for a direct measurement of the net glutamine accumulation. Mathematical modeling of 1H and 15N MRS data allowed to reduce the number of assumptions and provided reliable determination of GS (0.30±0.050??mol/g per minute), apparent neurotransmission (0.26±0.030??mol/g per minute), glutamate dehydrogenase (0.029±0.002??mol/g per minute), and net glutamine accumulation (0.033±0.001??mol/g per minute). These results showed an increase of GS and net glutamine accumulation under hyperammonemia, supporting the concept of their implication in cerebral ammonia detoxification. PMID:22167234

  19. 78 FR 6273 - IRS Truncated Taxpayer Identification Numbers; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-30

    ...301 [REG-148873-09] RIN 1545-BJ16 IRS Truncated Taxpayer Identification Numbers...Correction AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Correction to notice...taxpayer identifying number known as an IRS truncated taxpayer identification...

  20. 78 FR 15337 - IRS Truncated Taxpayer Identification Numbers; Hearing Cancellation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-11

    ...301 [REG-148873-09] RIN 1545-BJ16 IRS Truncated Taxpayer Identification Numbers...Cancellation AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Cancellation of...taxpayer identifying number known as an IRS truncated taxpayer identification...

  1. Matrix laser IR-visible image converter

    SciTech Connect

    Lipatov, N I; Biryukov, A S [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

    2006-04-30

    A new type of a focal matrix IR-visible image converter is proposed. The pixel IR detectors of the matrix are tunable microcavities of VCSEL (vertical-cavity surface emitting laser) semiconductor microstructures. The image conversion is performed due to the displacements of highly reflecting cavity mirrors caused by thermoelastic stresses in their microsuspensions appearing upon absorption of IR radiation. Analysis of the possibilities of the converter shows that its sensitivity is 10{sup -3}-10{sup -2} K and the time response is 10{sup -4}-10{sup -3} s. These characteristics determine the practical application of the converter. (laser applications and other topics in quantum electronics)

  2. Holographic RG flows with nematic IR phases

    E-print Network

    Cremonini, Sera; Rong, Junchen; Sun, Kai

    2014-01-01

    We construct zero-temperature geometries that interpolate between a Lifshitz fixed point in the UV and an IR phase that breaks spatial rotations but preserves translations. We work with a simple holographic model describing two massive gauge fields coupled to gravity and a neutral scalar. Our construction can be used to describe RG flows in non-relativistic, strongly coupled quantum systems with nematic order in the IR. In particular, when the dynamical critical exponent of the UV fixed point is z=2 and the IR scaling exponents are chosen appropriately, our model realizes holographically the scaling properties of the bosonic modes of the quadratic band crossing model.

  3. Synthesis and anti-inflammatory evaluation of new substituted 1-(3-chlorophenyl)-3-(4-methoxyphenyl)-1H-pyrazole derivatives.

    PubMed

    Fahmy, Hoda H; Khalifa, Nagy M; Nossier, Eman S; Abdalla, Mohamed M; Ismai, Magda M F

    2012-01-01

    A series of heterocyclic derivatives including 1,2,4-triazole-3(4H)-one (3a,b), 1H-pyrazol-5(4H)-one (4,5), 1H-pyrazol-4-carbonitrile (7), pyridine-3-carbonitrile (8, 9a,b), pyrimidine-5-carbonitrile (10a,b), methylpyrimidin-2(1H)-one or thione (11a,b), pyrimidine-5-carboxylate (12a,b), quinazolin-5(6H)-one (13a,b) and indeno [1,2-d] pyrimidin-5-one (14a,b) moieties conjugated with 1,3-disubstituted pyrazole moiety were synthesized on reaction with semicarbazide, thiosemicarbazide, 3-amino-5-oxo-2-pyrazoline, cyanoacetohydrazide, 2-acetyl thiophene, p-chloroacetophenone, urea, thiourea and 1,3-dicarbonyl compounds, respectively, by using 1-(3-chlorophenyl)-3-(4-methoxyphenyl)-1H-pyrazole-4-carboxaldehyde (2) as starting material. The structures of all the newly synthesized products have been established on the basis of analytical and spectral data. The anti-inflammatory screening showed that most of the obtained compounds were found to have significant anti-inflammatory activities with prostaglandin inhibition at a dose level of 2.5 and 5 mg/kg comparable to celecoxib as a reference control. The ulcer indices of all compounds are mainly in the safe level (UI = 2.10-4.27) except for compounds 9a and 14a, which were highly ulcerogenic. PMID:22594255

  4. Preliminary L/T-separated cross sections for forward pion production on ^1H at intermediate Q^2

    NASA Astrophysics Data System (ADS)

    Volmer, Jochen

    1998-10-01

    for the Charged Pion Form Factor (F_?) Collaboration at the Thomas Jefferson National Accelerator Facility (TJNAF). The pion, as the lightest meson, is an ideal laboratory for testing theoretical predictions at the border of non perturbative and perturbative QCD (pQCD) regimes. At intermediate and high Q^2 reliable experimental data for the charged pion form factor (F_?) are scarce. Experiment E93021 (the charged pion form factor) took data for the ^1H(e,e^'?^+)n reaction in end station C late 1997 for Q^2 values of 0.6 - 1.6 (GeV/c)^2. The forward longitudinal response in this process is dominated by knockout of (virtual) pions. Preliminary L/T-separated cross sections will be presented, and plans to extract F_? from these data will be discussed.

  5. Concise route to a series of novel 3-(tetrazol-5-yl)quinoxalin-2(1H)-ones.

    PubMed

    Gunawan, Steven; Nichol, Gary; Hulme, Christopher

    2012-03-28

    This report presents a novel three step solution phase protocol to synthesize 3-(tetrazol-5-yl)quinoxalin-2(1H)-ones. The strategy utilizes ethyl glyoxalate and mono-N-Boc-protected-o-phenylenediamine derivatives in the Ugi-Azide multi-component reaction (MCR) to generate a unique 1,5-disubstituted tetrazole. Subsequent acid treatment stimulates a simultaneous Boc deprotection and intramolecular cyclization leading to bis-3,4-dihydroquinoxalinone tetrazoles. Direct oxidation using a stable solid-phase radical catalyst (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) with ceric ammonium nitrate (CAN) in catalytic fashion initiating aerobic oxidation, completes the entire procedure to generate a series of original unique bis-quinoxalinone tetrazoles. The method was also expanded to produce a bis-benzodiazepine tetrazole. PMID:22707799

  6. Concise route to a series of novel 3-(tetrazol-5-yl)quinoxalin-2(1H)-ones

    PubMed Central

    Gunawan, Steven; Nichol, Gary; Hulme, Christopher

    2012-01-01

    This report presents a novel three step solution phase protocol to synthesize 3-(tetrazol-5-yl)quinoxalin-2(1H)-ones. The strategy utilizes ethyl glyoxalate and mono-N-Boc-protected-o-phenylenediamine derivatives in the Ugi-Azide multi-component reaction (MCR) to generate a unique 1,5-disubstituted tetrazole. Subsequent acid treatment stimulates a simultaneous Boc deprotection and intramolecular cyclization leading to bis-3,4-dihydroquinoxalinone tetrazoles. Direct oxidation using a stable solid-phase radical catalyst (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) with ceric ammonium nitrate (CAN) in catalytic fashion initiating aerobic oxidation, completes the entire procedure to generate a series of original unique bis-quinoxalinone tetrazoles. The method was also expanded to produce a bis-benzodiazepine tetrazole. PMID:22707799

  7. Real-Time Monitoring of New Delhi Metallo-?-Lactamase Activity in Living Bacterial Cells by 1H NMR Spectroscopy**

    PubMed Central

    Ma, Junhe; McLeod, Sarah; MacCormack, Kathleen; Sriram, Shubha; Gao, Ning; Breeze, Alexander L; Hu, Jun

    2014-01-01

    Disconnections between in vitro responses and those observed in whole cells confound many attempts to design drugs in areas of serious medical need. A method based on 1D 1H NMR spectroscopy is reported that affords the ability to monitor the hydrolytic decomposition of the carbapenem antibiotic meropenem inside Escherichia coli cells expressing New Delhi metallo-?-lactamase subclass 1 (NDM-1), an emerging antibiotic-resistance threat. Cell-based NMR studies demonstrated that two known NDM-1 inhibitors, L-captopril and ethylenediaminetetraacetic acid (EDTA), inhibit the hydrolysis of meropenem in vivo. NDM-1 activity in cells was also shown to be inhibited by spermine, a porin inhibitor, although in an in vitro assay, the influence of spermine on the activity of isolated NDM-1 protein is minimal. This new approach may have generic utility for monitoring reactions involving diffusible metabolites in other complex biological matrices and whole-cell settings, including mammalian cells. PMID:24458501

  8. Crystal structure and luminescent properties of [1-(biphenyl-4-yl)-1H-imidazole-?N 3]di­chloridozinc

    PubMed Central

    Liu, Xiao-Xiao; Wang, Yuan

    2015-01-01

    The mononuclear title compound, [ZnCl2(C15H12N2)2], was synthesized by reaction of zinc chloride and 1-(biphenyl-4-yl)-1H-imidazole (bpi) under hydro­thermal conditions. The ZnII atom is tetra­hedrally coordinated by the free imidazole N atoms of two bpi ligands and by two Cl atoms. The bpi ligands are not planar, with dihedral angles of 37.52?(14) and 42.45?(14)° between the phenyl rings and 37.13?(14) and 40.05?(14)° between the phenyl rings and the attached imidazole rings, respectively. Mutual ?–? inter­actions, with a centroid-to-centroid distance of 3.751?(2)?Å between the phenyl and imidazole rings of neighbouring ligands, are present, leading to dimers that are arranged in rows parallel to [-211]. PMID:25844185

  9. PKC{delta}-mediated IRS-1 Ser24 phosphorylation negatively regulates IRS-1 function

    SciTech Connect

    Greene, Michael W. [Bassett Research Institute, Mary Imogene Bassett Hospital, Cooperstown, NY 13326 (United States)]. E-mail: michael.greene@bassett.org; Ruhoff, Mary S. [Bassett Research Institute, Mary Imogene Bassett Hospital, Cooperstown, NY 13326 (United States); Roth, Richard A. [Department of Molecular Pharmacology, Stanford University School of Medicine, Stanford, CA 94305 (United States); Kim, Jeong-a [Diabetes Unit, National Center for Complementary and Alternative Medicine, National Institutes of Health, Bethesda, MD 20892 (United States); Quon, Michael J. [Diabetes Unit, National Center for Complementary and Alternative Medicine, National Institutes of Health, Bethesda, MD 20892 (United States); Krause, Jean A. [Bassett Research Institute, Mary Imogene Bassett Hospital, Cooperstown, NY 13326 (United States)

    2006-10-27

    The IRS-1 PH and PTB domains are essential for insulin-stimulated IRS-1 Tyr phosphorylation and insulin signaling, while Ser/Thr phosphorylation of IRS-1 disrupts these signaling events. To investigate consensus PKC phosphorylation sites in the PH-PTB domains of human IRS-1, we changed Ser24, Ser58, and Thr191 to Ala (3A) or Glu (3E), to block or mimic phosphorylation, respectively. The 3A mutant abrogated the inhibitory effect of PKC{delta} on insulin-stimulated IRS-1 Tyr phosphorylation, while reductions in insulin-stimulated IRS-1 Tyr phosphorylation, cellular proliferation, and Akt activation were observed with the 3E mutant. When single Glu mutants were tested, the Ser24 to Glu mutant had the greatest inhibitory effect on insulin-stimulated IRS-1 Tyr phosphorylation. PKC{delta}-mediated IRS-1 Ser24 phosphorylation was confirmed in cells with PKC{delta} catalytic domain mutants and by an RNAi method. Mechanistic studies revealed that IRS-1 with Ala and Glu point mutations at Ser24 impaired phosphatidylinositol-4,5-bisphosphate binding. In summary, our data are consistent with the hypothesis that Ser24 is a negative regulatory phosphorylation site in IRS-1.

  10. Complexes with hybrid phosphorus-NHC ligands: pincer-type Ir hydrides, dinuclear Ag and Ir and tetranuclear Cu and Ag complexes.

    PubMed

    Liu, Xianghao; Braunstein, Pierre

    2013-07-01

    Three types of hybrid phosphorus-imidazolium salts, 1-methyl-3-(3-((diphenylphosphino)methyl)benzyl)-1H-imidazol-3-ium hexafluorophosphate (2·PF6), 1-methyl-3-(3-(di-tert-butylphosphinooxy)phenyl)imidazolium iodide (8a), and 3-(3-((diphenylphosphoryl)methyl)phenyl)-1-methyl-1H-imidazol-3-ium iodide (11) have been prepared and used as precursors to phosphine-NHC, phosphinite-NHC, and phosphoryl-NHC metal complexes, respectively. The structure of 11 has been determined by X-ray diffraction. The Ag(I) and Ir(I) complexes of the phosphine-NHC ligand, [Ag(?-P-NHC,?C,?P)]2(PF6)2 (3) and [Ir(cod)(?-P-NHC,?C,?P)]2(PF6)2 (4), were obtained and characterized by NMR, ESI-MS, elemental analysis, and X-ray diffraction. Both complexes are dinuclear and dicationic, with two P-NHC ligands bridging the two metal centers. The presence of the P donor led for 3 to an unprecedented structure compared to that of related Ag(I) complexes with trans spanning bis-NHC ligands. Complex 4 is the first example of a dinuclear iridium complex with a hybrid P-NHC ligand. The new hydrido, Ir(III) pincer-type complex [IrH(CNHCCCNHC)(MeCN)]PF6 (7) is suggested to have a square-pyramidal structure. The tetranuclear Ag(I) complex with the phosphinite-NHC ligand, [Ag2(?3-I)(?-PO-NHC,?P,?CNHC)]2 (9a) has a cubane-type structure, with alternating silver and iodine apexes and two PO-NHC ligands bridging opposite edges of the Ag4 tetrahedron. The Ir(III) pincer complexes [IrH(I)(PO-NHC,?P,?C,?CNHC)(Me)] (10a) and [IrH(I)(PO-NHC,?P,?C,?CNHC)(n-Bu)] (10b), with Me or n-Bu substituents on the nitrogen atom, respectively, have been prepared and characterized. Ag(I) and Cu(I) complexes with the phosphoryl-NHC ligand are reported and the centrosymmetric structure of the latter, [Cu(OP-NHC,?CNHC)2(?-I){Cu(?-I)}]2 (13), was established by X-ray diffraction and consists of a central Cu2(?-I)2 rhombus connected by single iodide bridges to two Cu(OP-NHC,?CNHC)2 moieties. The Ir(III) hydride pincer complexes 10a,b were tested as catalyst precursors for the C-H bond activation of alkanes. Although their efficiency was significantly lower for transfer dehydrogenation from cyclooctane (coa) to t-butylethylene (tbe) than that of known PCP-Ir systems, these results represent the first attempts to study the catalytic properties of hybrid P-NHC iridium pincer complexes. PMID:23750783

  11. K6irs1, K6irs2, K6irs3, and K6irs4 Represent the Inner-Root-Sheath-Specific Type II Epithelial Keratins of the Human Hair Follicle1

    Microsoft Academic Search

    Lutz Langbein; Michael A Rogers; Silke Praetzel; Hermelita Winter; Jürgen Schweizer

    2003-01-01

    In this study we report on the cloning of two novel human type II keratin cDNAs, K6irs3 and K6irs4, which were specifically expressed in the inner root sheath of the hair follicle. Together with the genes of two previously described type II inner root sheath keratins, K6irs1 and K6irs2, the K6irs3 and K6irs4 genes were subclustered in the type II

  12. Vibrational and electronic absorption spectral studies of 5-amino-1-(4-bromophenyl)-3-phenyl-1-H-pyrazole

    NASA Astrophysics Data System (ADS)

    Prasad, M. V. S.; Chaitanya, Kadali; Udaya Sri, N.; Veeraiah, V.

    2012-12-01

    The FT-IR and FT-Raman spectra of 5-amino-1-(4-bromophenyl)-3-phenyl-1-H-pyrazole have been measured in the regions 4000-400 cm-1 and 3500-100 cm-1, respectively. The equilibrium geometry, bonding features and harmonic vibrational frequencies have been carried out with the help of DFT method. The assignments of the vibrational spectra have been carried out with the normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMFF). The first-order hyperpolarizability (?0) and related properties (?, ?0, and ??) of 5A4BP3PP are calculated by using HF/6-31G(d,p) method on the finite field approach. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bonding orbital (NBO) analysis. The results show that electron density (ED) in the ?* and ?* antibonding orbitals and second order delocalization energies E(2) confirms the occurrence of the intramolecular charge transfer (ICT) within the molecule. UV-vis spectrum of the compound was recorded and the electronic properties, such as HOMO and LUMO energies, were performed by TDDFT using 6-31G(d,p). The HOMO-LUMO calculations indicating the charge transfer takes place within the molecule.

  13. Named Reactions

    NSDL National Science Digital Library

    This Web site lists 95 of the most important named reactions in organic chemistry. Each is linked to a Web page that gives the primary reference and equations for one or more recent literature examples that illustrate the use of the reaction.

  14. Reaction Time

    NSDL National Science Digital Library

    New York Hall of Science

    1999-01-01

    In this activity, learners explore reaction time and challenge themselves to improve their coordination. Do you want to move faster? Catch that ball that you never seem to see in time? Use a simple test to help you improve your reaction (or response) time.

  15. Iridium(III) emitters based on 1,4-disubstituted-1H-1,2,3-triazoles as cyclometalating ligand: synthesis, characterization, and electroluminescent devices.

    PubMed

    Fernández-Hernández, Jesús M; Beltrán, Juan I; Lemaur, Vincent; Gálvez-López, Maria-Dolores; Chien, Chen-Han; Polo, Federico; Orselli, Enrico; Fröhlich, Roland; Cornil, Jérôme; De Cola, Luisa

    2013-02-18

    A series of blue and blue-green emitters based on neutral bis- and tris-cyclometalated Ir(III) complexes with 1-benzyl-4-(2,6-difluorophenyl)-1H-1,2,3-triazole (dfptrBn) as cyclometalating ligand is reported. The bis-cyclometalated complexes of the type [Ir(dfptrBn)(2)(L(^)X)] with different ancillary ligands, L(^)X = picolinate (pic) (2) or 2-(5-(perfluorophenyl)-2H-1,2,4-triazol-3-yl)pyridine (pytrF(5)) (3), are described and their photophysical properties compared with the analogous complexes containing the archetypal 2-(2,4-difluorophenyl)pyridinato (dfppy) as cyclometaled ligand (C(^)N). Complex 2 exhibits a marked solvatochromic behavior, from 475 nm in toluene to 534 nm in formamide, due to the strong MLCT character of its emissive excited state. Complex 3 displays a true-blue emission, narrower in the visible part than FIrpic. In addition, the homoleptic complex [Ir(dfprBn)(3)] (4) and the heteroleptic compounds with mixed arylpyridine/aryltriazole ligands, [Ir(dfptrBn)(2)(C(^)N)] (C(^)N = 2-phenylpyridinato (ppy) (5) or dfppy (6)), have been synthesized and fully characterized. The facial (fac) complex fac-4 is emissive at 77 K showing a deep-blue emission, but it is not luminescent in solution at room temperature similarly to their phenylpyrazole counterparts. However, the fac isomers, fac-5 and fac-6, are highly emissive in solution and thin films, reaching emission quantum yields of 76%, with emission colors in the blue to blue-green region. The photophysical properties for all complexes have been rationalized by means of quantum-chemical calculations. In addition, we constructed electroluminescent devices, organic light-emitting diodes (OLEDs) by sublimation of fac-6, and by solution processed polymer-based devices (PLEDs) using complexes fac-5 or fac-6 as dopants. PMID:23383706

  16. Chemical Reactions

    NSDL National Science Digital Library

    Mrs. Hicken

    2009-05-04

    We are going go over a general view of reactions to prepare us for our unit on Chemical Reactions! Have fun learning! WARNING: If you are caught looking at ANY other site, without permission, you will be sent to the ALC, and you will not participate in any other computer activities for the rest of the year. Get your worksheet and begin! Overview Take this quiz and have me come over and sign off on your worksheet when you have completed the quiz! Overview Quiz Next let's take a look at what effect the rate of a chemical reaction. Rates of Reactions Another quiz, another check off by me! Rates of Reactions Quiz Now how do we measure how fast a ...

  17. Synthesis, crystal structures and theoretical calculations of new 1-[2-(5-chloro-2-benzoxazolinone-3-yl)acetyl]-3,5-diphenyl-4,5-dihydro-(1H)-pyrazoles

    NASA Astrophysics Data System (ADS)

    Gök?en, Umut Salg?n; Alpaslan, Yelda Bingöl; Kelekçi, Nesrin Gökhan; I??k, ?amil; Ekizo?lu, Melike

    2013-05-01

    1-[2-(5-Chloro-2-benzoxazolinone-3-yl)acetyl]-3-phenyl-5-(3-methoxyphenyl)-4,5-dihydro-(1H)-pyrazole (5a), 1-[2-(5-chloro-2-benzoxazolinone-3-yl)acetyl]-3-phenyl-5-(3,4-dimethoxyphenyl)-4,5-dihydro-(1H)-pyrazole (5b) and 1-[2-(5-chloro-2-benzoxazolinone-3-yl)acetyl]-3-(4-methylphenyl)-5-(2,3-dimethoxyphenyl)-4,5-dihydro-(1H)-pyrazole (5c) were synthesized. The crystal and molecular structures of the compounds 5a, 5b and 5c were determined by elemental analyses, IR, 1H NMR, ESI-MS and single-crystal X-ray diffraction. DFT method with 6-31G(d,p) basis set was used to calculate the optimized geometrical parameters, vibrational frequencies and chemical shift values. The calculated vibrational frequencies and chemical shift values were compared with experimental IR and 1H NMR values. The results represented that there was a good agreement between experimental and calculated values of the compounds 5a-5c. In addition, DFT calculations of the compounds, molecular electrostatic potentials (MEPs) and frontier molecular orbitals were performed at B3LYP/6-31G(d,p) level of theory. Furthermore, compounds were tested against three Gram-positive bacteria: Staphylococcus aureus ATCC 29213 (American Type Culture Collection), methicillin resistant S. aureus (MRSA) ATCC 43300 and Enterococcus faecalis ATCC 29212; two Gram negative bacteria: Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853; and three fungi: Candida albicans ATCC 90028, Candida krusei ATCC 6258 and Candida parapsilosis ATCC 90018. In general, all of the compounds were found to be slightly active against tested microorganisms.

  18. Atmospheric Effects in IR Color

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released August 3, 2004 This image shows two representations of the same infra-red image covering parts of Ius Chasma and Oudemans Crater. On the left is a grayscale image showing surface temperature, and on the right is a false-color composite made from 3 individual THEMIS bands. The false-color image is colorized using a technique called decorrelation stretch (DCS), which emphasizes the spectral differences between the bands to highlight compositional variations.

    This image is dominated by atmospheric effects. The pink/magenta colors inside the canyon show areas with a large amount of atmospheric dust. In the bottom half of the image, the patchy blue/cyan colors indicate the presence of water ice clouds out on the plains. Water ice clouds and high amounts of dust do not generally occur at the same place and time on Mars because the dust absorbs sunlight and heats the atmosphere. The more dust that is present, the warmer the atmosphere becomes, sublimating the water ice into water vapor and dissipating any clouds.

    Image information: IR instrument. Latitude -8.2, Longitude 267.9 East (92.1.West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  19. Melas Chasma in IR Color

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released August 11, 2004 This image shows two representations of the same infra-red image over Melas Chasma. On the left is a grayscale image showing surface temperature, and on the right is a false-color composite made from 3 individual THEMIS bands. The false-color image is colorized using a technique called decorrelation stretch (DCS), which emphasizes the spectral differences between the bands to highlight compositional variations.

    There is a distinct purple/blue layer present in the northern wall of the Chasma. Although this layer likely has a composition different than the surrounding areas, it is difficult to interpret its specific composition due to the high variability of sunlit and shaded surfaces in this area, which cause a wide range of temperatures to be present within each pixel of the image. It is possible that this layer has a unique composition due to differences in the volcanic or sedimentary environment at the time that the rock formed, or it could be a layer of magma injected between two previously existing rock layers. Another possibility is that the wall is mostly covered by dust and debris, and this portion contains the only exposed bedrock. The light blue colors present in many other areas of the Chasma are due to water ice clouds.

    Image information: IR instrument. Latitude -8.9, Longitude 282 East (78 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  20. Gale Crater in IR Color

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released August 4, 2004 This image shows two representations of the same infra-red image of Gale Crater. On the left is a grayscale image showing surface temperature, and on the right is a false-color composite made from 3 individual THEMIS bands. The false-color image is colorized using a technique called decorrelation stretch (DCS), which emphasizes the spectral differences between the bands to highlight compositional variations.

    In the bottom of the crater, surrounding the central mound, there are extensive basaltic sand deposits. The basaltic sand spectral signature combined with the warm surface (due to the low albedo of basaltic sand) produces a very strong pink/magenta color. This color signature contrasts with the green/yellow color of soil and dust in the top of the image, and the cyan color due to the presence of water ice clouds at the bottom of the image. This migrating sand may be producing the erosional features seen on the central mound.

    Image information: IR instrument. Latitude -4.4, Longitude 137.4 East (222.6 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  1. Ice Clouds in Color IR

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released August 9, 2004 This image shows two representations of the same infra-red image in the Elysium region of Mars. On the left is a grayscale image showing surface temperature, and on the right is a false-color composite made from 3 individual THEMIS bands. The false-color image is colorized using a technique called decorrelation stretch (DCS), which emphasizes the spectral differences between the bands to highlight compositional variations.

    The light blue area in the center of this image is a very nice example of a water ice cloud. Water ice is frequently present in the Martian atmosphere as a thin haze. Clouds such as this one can be difficult to identify in a temperature image, but are easy to spot in the DCS images. In this case, the water ice is relatively confined and concentrated which may be due to the topography of the Elysium volcanic construct.

    Image information: IR instrument. Latitude 23.2, Longitude 150.1 East (209.9 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  2. Lava Flows in IR Color

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released August 5, 2004 This image shows two representations of the same infra-red image covering a portion of the Solis Planum region, southeast of the Tharsis volcanoes. On the left is a grayscale image showing surface temperature, and on the right is a false-color composite made from 3 individual THEMIS bands. The false-color image is colorized using a technique called decorrelation stretch (DCS), which emphasizes the spectral differences between the bands to highlight compositional variations.

    Multiple layers of lava flows in this region show temperature differences, as well as some potential compositional differences. The temperature variations between these flows are likely caused by differences in their surface texture. The compositional variation could be due to differences in the make-up of the lava when it erupted onto the surface or might only reflect differences in the amount of dust covering these flows.

    Image information: IR instrument. Latitude -30.1, Longitude 275.9 East (84.1 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  3. Translational and rotational diffusion of glycerol by means of field cycling 1H NMR relaxometry.

    PubMed

    Kruk, D; Meier, R; Rössler, E A

    2011-02-10

    Field cycling (FC) (1)H NMR relaxometry has been applied to study translational and rotational dynamics of nondeuterated (-h(8)) and partially deuterated (-h(3) and -h(5)) glycerol in a broad temperature range. We demonstrate that a low-frequency excess intensity observed in the relaxation dispersion stems from intermolecular dipole-dipole interactions mediated by translational dynamics, whereas the main relaxation is attributed to rotational dynamics. A theoretical description of the relaxation processes is formulated accounting for (1)H-(1)H as well as (1)H-(2)H relaxation channels for the partially deuterated systems. While the intermolecular spectral density is derived from the force-free-hard-sphere model (Fick diffusion with appropriate boundary conditions) of translational motion, the intramolecular relaxation contribution is described by a Cole-Davidson spectral density. This ansatz reproduces very well the dispersion profiles obtained from FC (1)H NMR. Moreover, the approach allows extracting the diffusion coefficient D, which is in good agreement with results from gradient (1)H NMR. Thus, (1)H NMR relaxometry has the potential to become an alternative method for measuring the diffusion coefficient in viscous liquids. PMID:21244060

  4. IR Optimization, DID and anti-DID

    SciTech Connect

    Seryi, Andrei; Maruyama, Takashi; /SLAC; Parker, Brett; /Brookhaven

    2006-02-03

    In this paper, we discuss optimization of the larger crossing angle Interaction Region of the Linear Collider, where specially shaped transverse field of the Detector Integrated Dipole can be reversed and adjusted to optimize trajectories of the low energy pairs, so that their majority would be directed into the extraction exit hole. This decreases the backscattering and makes background in 14mrad IR to be similar to background in 2mrad IR.

  5. Tissue-specific insulin resistance in mice with mutations in the insulin receptor, IRS-1, and IRS-2

    Microsoft Academic Search

    Yoshiaki Kido; Deborah J. Burks; Dominic Withers; Jens C. Bruning; C. Ronald Kahn; Morris F. White; Domenico Accili

    2000-01-01

    Type 2 diabetes is characterized by abnormalities of insulin action in muscle, adipose tissue, and liver and by altered ?-cell function. To analyze the role of the insulin signaling pathway in these processes, we have generated mice with combined heterozygous null mutations in insulin receptor (ir), insulin receptor substrate (irs-1), and\\/or irs-2. Diabetes developed in 40% of ir\\/irs-1\\/irs-2 +\\/- ,

  6. Development of an IR stimulator concept for testing IR missile warning systems

    NASA Astrophysics Data System (ADS)

    Robinson, William G.; Farrier, David A.

    1999-07-01

    Missile warning systems (MWS) present unique problems for hardware-in-the-loop testing compared to other sensors found on modern day military aircraft and ground vehicles. End-to- end testing of an IR MWS like the AN/AAR-44 and other IR MWS requires a scene projector or stimulator capable of large intensity dynamic range, moderate temporal response, and a very large field of regard. These requirements dictate a different type of stimulator than is normally used with more conventional IR imaging systems using IR focal plane arrays and relatively narrow fields of view on the order of 10 - 30 degrees. This paper describes an initial design approach for development of an IR stimulator that satisfies the requirements for hardware and software testing of the AN/AAR-44 and other IR MWS equipment.

  7. IR diver vision for turbidity mitigation

    NASA Astrophysics Data System (ADS)

    Milam, Jerry A.

    2010-04-01

    Commercial, forensic, and military divers often encounter turbid conditions which reduce visibility to zero. Under such conditions, work must be performed completely blind. The darkness resulting from high levels of turbidity is complete, and can be dangerous as well as disorienting. Such darkness can even occur near the surface on a bright and sunny day. Artificial underwater lighting is of no use in such situations, as it only makes matters worse (similar to the use of high beam headlights in dense fog). Certain wavelengths of infrared (IR) light have the ability to penetrate this underwater "fog," and thus form the basis of the current development. Turbidity results from clay, silt, finely divided organic and inorganic matter, soluble colored organic compounds, plankton and microscopic organisms suspended in water. The IR Diver Vision system described herein consists of a standard commercial diving mask of any of several configurations whereby an IR light source, IR video camera, video display, and power source may be integrated within or attached to the mask. The IR light source wavelength is compatible with the spectral bandwidth of the video camera. The camera field-of-view (FOV) is matched to the video display in order to provide a unity magnification and hence prevent diver ocular fatigue. The IR video camera, video display, power source and controls are compatible with extended use in a submarine environment. Some such masks will incorporate tilt/heading sensors and video indicators. 3-D Imaging, Inc. has developed prototypes and has patents pending on such devices.

  8. Intermolecular Interactions between Eosin Y and Caffeine Using (1)H-NMR Spectroscopy.

    PubMed

    Okuom, Macduff O; Wilson, Mark V; Jackson, Abby; Holmes, Andrea E

    2013-12-31

    DETECHIP has been used in testing analytes including caffeine, cocaine, and tetrahydrocannabinol (THC) from marijuana, as well as date rape and club drugs such as flunitrazepam, gamma-hydroxybutyric acid (GHB), and methamphetamine. This study investigates the intermolecular interaction between DETECHIP sensor eosin Y (DC1) and the analyte (caffeine) that is responsible for the fluorescence and color changes observed in the actual array. Using (1)H-NMR, (1)H-COSY, and (1)H-DOSY NMR methods, a proton exchange from C-8 of caffeine to eosin Y is proposed. PMID:25018772

  9. High Resolution 1H Detected 1H,13C Correlation Spectra in MAS Solid-State NMR using Deuterated Proteins with Selective 1

    E-print Network

    Skrynnikov, Nikolai

    Proteins with Selective 1 H,2 H Isotopic Labeling of Methyl Groups Vipin Agarwal, Anne Diehl, Nikolai which is presented in this pilot study avoids this pitfall by labeling of methyl groups as originally proposed by Kay and co-workers.10 The labeling protocol involves growing cells in 90% D2O, using 3-[66%-2H

  10. Xanthan Gum Removal for 1H-NMR Analysis of the Intracellular Metabolome of the Bacteria Xanthomonas axonopodis pv. citri 306

    PubMed Central

    Pegos, Vanessa R.; Canevarolo, Rafael R.; Sampaio, Aline P.; Balan, Andrea; Zeri, Ana C. M.

    2014-01-01

    Xanthomonas is a genus of phytopathogenic bacteria, which produces a slimy, polysaccharide matrix known as xanthan gum, which involves, protects and helps the bacteria during host colonization. Although broadly used as a stabilizer and thickener in the cosmetic and food industries, xanthan gum can be a troubling artifact in molecular investigations due to its rheological properties. In particular, a cross-reaction between reference compounds and the xanthan gum could compromise metabolic quantification by NMR spectroscopy. Aiming at an efficient gum extraction protocol, for a 1H-NMR-based metabolic profiling study of Xanthomonas, we tested four different interventions on the broadly used methanol-chloroform extraction protocol for the intracellular metabolic contents observation. Lower limits for bacterial pellet volumes for extraction were also probed, and a strategy is illustrated with an initial analysis of X. citri’s metabolism by 1H-NMR spectroscopy. PMID:24957023

  11. Antimycobacterial evaluation of novel [4,5-dihydro-1H-pyrazole-1-carbonyl]pyridine derivatives synthesized by microwave-mediated Michael addition.

    PubMed

    Sedighi, Vida; Azerang, Parisa; Sardari, Soroush

    2015-06-01

    The focus of this study is the synthesis and biological activity evaluation of a series of dibenzalaceton derivatives (3a-3n) and novel [4,5-dihydro-1H-pyrazole-1-carbonyl]pyridine derivatives (5a-5g) against Mycobacterium bovis, Bacillus Calmette-Guerin (BCG). Dibenzalacetone derivatives were synthesized by benzaldehyde derivatives. The [4,5-dihydro-1H-pyrazole-1-carbonyl]pyridine derivatives were synthesized by Michael addition reaction and using green chemistry microwave-mediated method. All compounds were evaluated against BCG and the activity expressed as minimum inhibitory concentration (MIC) in ?M. The result showed good activity for all the compounds especially compounds (3a), (3n), and (5a) illustrated high activity (7.03, 8.10 and 5.37??M, respectively). Copyright © 2014 John Wiley & Sons, Ltd. PMID:25219796

  12. 5-( [aryl or aryloxy (or thio)]methyl)-3-(1H-imidazol-1-ylmethyl)-3- (2-thienyl)-2-methylisoxazolidine derivatives as novel antifungal agents.

    PubMed

    Mullen, G B; Mitchell, J T; Allen, S D; St Georgiev, V

    1988-12-01

    The in vitro antifungal activity of a novel series of cis- and trans-5-([aryl or aryloxy (or thio)]methyl)-3-(1H-imidazol-1-ylmethyl)-3- (2-thienyl)-2-methylisoxazolidines (13-24) was evaluated and compared with ketoconazole. The title series of compounds was prepared via a 1,3-dipolar cycloaddition reaction of 1-(2-thienyl)-2-(1H-imidazol-1-yl)-N-methylethanimine N-oxides with appropriate styrenes, allyl phenyl ethers, or allyl phenyl thioether precursors. The resulting products were mixtures of the corresponding cis- and trans-diastereomers which were readily separated by flash chromatography on neutral silica gel. The majority of compounds 13-24, when tested in solid agar cultures, exhibited moderate to potent activity against Trichophyton rubrum, Aspergillus fumigatus, and Candida albicans at concentrations ranging between less than or equal to 2.0 and 70.0 micrograms/mL. PMID:3244110

  13. Time-resolved IR spectroscopy of a trinuclear palladium complex in solution.

    PubMed

    Zimmer, M; Rupp, F; Singer, P; Walz, F; Breher, F; Klopper, W; Diller, R; Gerhards, M

    2015-06-01

    This paper presents a combined spectroscopic and theoretical analysis of a trinuclear [Pd3{Si(mt(Me))3}2] complex (mt(Me) = methimazole) which has been demonstrated to be a potential catalyst for coupling reactions. It is a highly symmetric model system (D3 in the electronic ground state) for the investigation of electronic states and the structure of polynuclear transition metal complexes. Different time-resolved IR spectroscopic methods covering the femtosecond up to the microsecond range as well as density functional computations are performed to unravel the structure and character of this complex in the electronically excited state. These are the first time-resolved IR studies on a trinuclear Pd complex. Based on the interplay between the computational results and those from the IR studies a (3)A state is identified as the lowest lying triplet state which has C2 symmetry. PMID:25959720

  14. Combined 1H-NMR and 1H-13C HSQC-NMR to improve urinary screening in autism spectrum disorders.

    PubMed

    Nadal-Desbarats, Lydie; Aïdoud, Nacima; Emond, Patrick; Blasco, Hélène; Filipiak, Isabelle; Sarda, Pierre; Bonnet-Brilhault, Frédérique; Mavel, Sylvie; Andres, Christian R

    2014-07-01

    Autism spectrum disorders (ASD) are neurodevelopmental diseases with complex genetic and environmental etiological factors. Although genetic causes play a significant part in the etiology of ASD, metabolic disturbances may also play a causal role or modulate the clinical features of ASD. The number of ASD studies involving metabolomics is increasing, and sometime with conflicting findings. We assessed the metabolomics profiling of urine samples to determine a comprehensive biochemical signature of ASD. Furthermore, to date no study has combined metabolic profiles obtained from different analytical techniques to distinguish patient with ASD from healthy individuals. We obtained (1)H-NMR spectra and 2D (1)H-(13)C HSQC NMR spectra from urine samples of patients with ASD or healthy controls. We analyzed these spectra by multivariate statistical data analysis. The OPLS-DA model obtained from (1)H NMR spectra showed a good discrimination between ASD samples and non-ASD samples (R(2)Y(cum) = 0.70 and Q(2) = 0.51). Combining the (1)H NMR spectra and the 2D (1)H-(13)C HSQC NMR spectra increased the overall quality and predictive value of the OPLS-DA model (R(2)Y(cum) = 0.84 and Q(2) = 0.71), leading to a better sensitivity and specificity. Urinary excretion of succinate, glutamate and 3-methyl-histidine differed significantly between ASD and non-ASD samples. Urinary screening of children with neurodevelopmental disorders by combining NMR spectroscopies (1D and 2D) in multivariate analysis is a better sensitive and a straightforward method that could help the diagnosis ASD. PMID:24841505

  15. Enhanced blocking temperature in (Pt/Co)3/IrMn/Co and (Pd/Co)3/IrMn/Co trilayers with ultrathin IrMn layer

    NASA Astrophysics Data System (ADS)

    Vinai, G.; Moritz, J.; Bandiera, S.; Prejbeanu, I. L.; Dieny, B.

    2013-08-01

    IrMn blocking temperature (TB) is compared between IrMn/Co bilayers and (Pt/Co)3/IrMn/Co and (Pd/Co)3/IrMn/Co trilayers for different IrMn thicknesses. Exchange bias field (Hex) is measured from 5 to 400 K. Trilayers show a more concave thermal decrease of Hex(T) compared to bilayers and, for thin IrMn layers, larger TB and sharper peak of coercive field Hc around TB. This Hex(T) behaviour presents improved characteristics for thermally assisted-MRAM (TA-MRAM) applications, with large Hex/Hc ratio. Two physical explanations are proposed: an indirect IrMn intergrain coupling through the (Pt(Pd)/Co)3 layer and a reduction of IrMn/Co interfacial coupling due to out-of-plane canting of the IrMn spins.

  16. Fourier Transform Infrared (FT-IR) Spectroscopy of Atmospheric Trace Gases HCl, NO and SO2

    NASA Technical Reports Server (NTRS)

    Haridass, C.; Aw-Musse, A.; Dowdye, E.; Bandyopadhyay, C.; Misra, P.; Okabe, H.

    1998-01-01

    Fourier Transform Infrared (FT-IR) spectral data have been recorded in the spectral region 400-4000/cm of hydrogen chloride and sulfur dioxide with I/cm resolution and of nitric oxide with 0.25 cm-i resolution, under quasi-static conditions, when the sample gas was passed through tubings of aluminum, copper, stainless steel and teflon. The absorbance was measured for the rotational lines of the fundamental bands of (1)H(35)Cl and (1)H(37)Cl for pressures in the range 100-1000 Torr and for the (14)N(16)O molecule in the range 100-300 Torr. The absorbance was also measured for individual rotational lines corresponding to the three modes of vibrations (upsilon(sub 1) - symmetric stretch, upsilon(sub 2) - symmetric bend, upsilon(sub 3) - anti-symmetric stretch) of the SO2 molecule in the pressure range 25-150 Torr. A graph of absorbance versus pressure was plotted for the observed rotational transitions of the three atmospherically significant molecules, and it was found that the absorbance was linearly proportional to the pressure range chosen, thereby validating Beer's law. The absorption cross-sections were determined from the graphical slopes for each rotational transition recorded for the HCl, NO and SO2 species. Qualitative and quantitative spectral changes in the FT-IR data will be discussed to identify and characterize various tubing materials with respect to their absorption features.

  17. Analyzing powers for 1 H,, , p... at T 165 and 240 MeV

    E-print Network

    Maryland at College Park, University of

    for elastic scat- tering of from polarized 1 H for pion beam energies of T 165 and 240 MeV at several.5 T magnetic field. The target was dynamically polarized yielding a positive polarization normal to the scat

  18. 32 CFR 1630.15 - Class 1-H: Registrant not subject to processing for induction.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Registrant not subject to processing for induction. 1630.15 Section 1630.15...Registrant not subject to processing for induction. In Class 1-H shall be placed...currently subject to processing for...

  19. 32 CFR 1630.15 - Class 1-H: Registrant not subject to processing for induction.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Registrant not subject to processing for induction. 1630.15 Section 1630.15...Registrant not subject to processing for induction. In Class 1-H shall be placed...currently subject to processing for...

  20. Enzyme Reactions

    NSDL National Science Digital Library

    Maryland Virtual High School

    The enzyme reaction rate activity allows students to simulate the effects of variables such as temperature and pH on the reaction rate of the enzyme catalase. This computer simulation is best used after the students have done a wet lab experiment. The value of the simulation is that it requires the students to interpret and analyze the graphical representation of data and it enables the running of mutiple experiments in a short amount of time.

  1. Non-classical transformation of benzendiazonium hydrogen sulfates. Access to 1,3-dimethylisochromeno[4,3-c]pyrazol-5(1H)-one, a potential benzodiazepine receptor ligand.

    PubMed

    Maggio, Benedetta; Raffa, Demetrio; Raimondi, Maria Valeria; Daidone, Giuseppe

    2013-01-01

    The compound 2-((1,3-dimethyl-1H-pyrazol-5-yl)(methyl)carbamoyl)benzene-diazonium hydrogen sulfate (10) was reacted with copper sulfate and sodium chloride, in the presence of ascorbic acid as reducing agent, to afford a mixture of the chlorinated epimers 4'-chloro-2,2',5'-trimethyl-2',4'-dihydrospiro[isoindoline-1,3'-pyrazol]-3-one (18) and (19), the epimers 4'-hydroxy-2,2',5'-trimethyl-2',4'-dihydrospiro[isoindoline-1,3'-pyrazol]-3-one (20) and (21), and N-(1,3-dimethyl-1H-pyrazol-5-yl)benzamide (22). Under the foregoing conditions, diazonium salt 10 affords neither the 2-chloro-N-(1,3-dimethyl-1H-pyrazol-5-yl)-N-methylbenzamide (23) nor the tricyclic derivative 24, the classical products of the Sandmeyer and Pschorr reactions, respectively. Finally, by heating 20 at 210 °C the compound 1,3-dimethylisochromeno[4,3-c]pyrazol-5(1H)-one (24) was obtained. The transformation under the above conditions of 2-((4-chloro-3-methyl-1-phenyl- 1H-pyrazol-5-yl)(methyl)carbamoyl)benzendiazonium hydrogen sulphate (11) afforded 4',4'-dichloro-2,5'-dimethyl-2'-phenyl-2',4'-dihydrospiro[isoindoline-1,3'-pyrazol]-3-one (29) as the sole reaction product. PMID:24152597

  2. Stereo vision for small targets in IR image sequences

    NASA Astrophysics Data System (ADS)

    Jutzi, Boris; Gabler, Richard; Jaeger, Klaus

    2001-11-01

    Surveillance systems against missile attacks require the automatic detection of targets with low false alarm rate (FAR). Infrared Search and Track (IRST) systems offer a passive detection of threats at long ranges. For maximum reaction time and the arrangement of counter measurements, it is necessary to declare the objects as early as possible. For this purpose the detection and tracking algorithms have to deal with point objects. Conventional object features like shape, size and texture are usually unreliable for small objects. More reliable features of point objects are three-dimensional spatial position and velocity. At least two sensors observing the same scene are required for multi-ocular stereo vision. Mainly three steps are relevant for successful stereo image processing. First of all the precise camera calibration (estimating the intrinsic and extrinsic parameters) is necessary to satisfy the demand of high degree of accuracy, especially for long range targets. Secondly the correspondence problem for the detected objects must be solved. Thirdly the three-dimensional location of the potential target has to be determined by projective transformation. For an evaluation a measurement campaign to capture image data was carried out with real targets using two identical IR cameras and additionally synthetic IR image sequences have been generated and processed. In this paper a straightforward solution for stereo analysis based on stationary bin-ocular sensors is presented, the current results are shown suggestions for future work are given.

  3. Enhancing the photoluminescence of 1-(naphthalene-1-yl)-2,4,5-triphenyl-1H-imidazole anchored to superparamagnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Jayabharathi, J.; Karunakaran, C.; Kalaiarasi, V.; Ramanathan, P.; Prabhakaran, A.

    2015-01-01

    Synthesis and characterization of 1-(naphthalene-1-yl)-2,4,5-triphenyl-1H-imidazole has been carried out by spectral studies. The synthesized phosphated imidazole and phosphated imidazole bound magnetic nanoparticles were characterized using fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and powder X-ray diffraction (XRD). The photophysical characteristics of the synthesized phosphated imidazole and phosphated imidazole bound magnetic nanoparticles were investigated by steady-state absorption and emission spectra as well as time resolved fluorometry. The intensities of absorption and emission maxima increase in the following order, phosphated imidazole bound Fe2O3 > phosphated imidazole > imidazole.

  4. Experimental and DFT studies on the vibrational and electronic spectra of 2-(4,5-phenyl-1H-imidazole-2-yl)-phenol

    NASA Astrophysics Data System (ADS)

    Ye, Yunfeng; Tang, Guodong; Tang, Tingting; Culnane, Lance F.; Zhao, Jianyin; Zhang, Yu

    2015-02-01

    The compound 2-(4,5-phenyl-1H-imidazole-2-yl-phenol (PIP) was synthesized, followed by structure determination by X-ray diffraction, the results of which agree well with the calculated optimized, lowest energy geometrical structure. Vibrational information was obtained by FT-IR and Raman spectroscopy which also agree well with calculations (of harmonic vibration frequencies). The calculations were carried out with density functional theory B3LYP methods using 6-311++G** and LANL2DZ basis sets. Absorption UV-Vis experiments of PIP in CH3CH2OH solution reveal three maximum peaks at 245, 292 and 317 nm, which are in agreement with calculated electronic transitions using TD-B3LYP/6-311++G** in CH3CH2OH solution, and agree to the gas-phase calculations.

  5. 1H-14N cross-relaxation in trinitrotoluene - a step toward improved landmine detection

    Microsoft Academic Search

    Markus Nolte; Alexei Privalov; Jürgen Altmann; Vladimir Anferov; Franz Fujara

    2002-01-01

    Motivated by the lack of efficient detection techniques for metal-free trinitrotoluene (TNT) containing landmines, 1H-14N cross-relaxation experiments on TNT have been performed using field-cycling spectroscopy in an electronically switchable volume coil. Using 1H NMR detection (indirect method), the 14N quadrupole spectra in several small (about 0.5 g) TNT samples of different producers are determined. The experiment is considered as a

  6. Evaluation of 1H NMR relaxometry for the assessment of pore size distribution in soil samples

    Microsoft Academic Search

    F. Jaeger; S. Bowe; H. Van As; G. E. Schaumann

    2009-01-01

    1H NMR relaxometry is used in earth science as a non-destructive and time-saving method to determine pore size distributions (PSD) in porous media with pore sizes ranging from nm to mm. This is a broader range than generally reported for results from X-ray computed tomography (X-ray CT) scanning, which is a slower method. For successful application of 1H NMR relaxometry

  7. Tadross, Gilmore, Bugga, Virgil, and Stoltz Supporting Information Regioselective Reactions of Highly Substituted Arynes

    E-print Network

    Stoltz, Brian M.

    Flash P60 Academic Silica gel (particle size 0.040-0.063 mm) was used for flash chromatography. 1 H and 13.54; IR (NaCl/film) 3482, 2942, 1592, 1466, 1350, 1312, 1212, 1155, 1099, 1025, 813 cm­1 ; HRMS (MM: ESI

  8. Longitudinal 1H MRS changes in mild cognitive impairment and Alzheimer’s disease

    PubMed Central

    Kantarci, Kejal; Weigand, Stephen D.; Petersen, Ronald C.; Boeve, Bradley F.; Knopman, David S.; Gunter, Jeffrey; Reyes, Denise; Shiung, Maria; O’Brien, Peter C; Smith, Glenn E.; Ivnik, Robert J.; Tangalos, Eric G.; Jack, Clifford R.

    2009-01-01

    Magnetic Resonance (MR)- based volume measurements of atrophy are potential markers of disease progression in patients with amnestic mild cognitive impairment (aMCI) and Alzheimer’s disease (AD). Longitudinal changes in 1H MR spectroscopy (1H MRS) metabolite markers have not been characterized in aMCI subjects. Our objective was to determine the longitudinal 1H MRS metabolite changes in patients with aMCI, and AD, and to compare 1H MRS metabolite ratios and ventricular volumes in tracking clinical disease progression in AD. The neuronal integrity marker N-acetylaspartate/Creatine ratio declined in aMCI and AD patients compared to cognitively normal elderly. The changein 1H MRS metabolite ratios correlated with clinical progression about as strongly as the rate of ventricular expansion, suggesting that 1H MRS metabolite ratios may be useful markers for the progression of AD. Choline/Creatine ratio declined in stable aMCI, compared to converter aMCI patients and cognitively normal elderly, which may be related to a compensatory mechanism in aMCI patients who did not to progress to AD. PMID:16860440

  9. IGF-IR Targeted Therapy: Past, Present and Future

    PubMed Central

    Janssen, Joseph A. M. J. L.; Varewijck, Aimee J.

    2014-01-01

    The IGF-I receptor (IGF-IR) has been studied as an anti-cancer target. However, monotherapy trials with IGF-IR targeted antibodies or with IGF-IR specific tyrosine kinase inhibitors have, overall, been very disappointing in the clinical setting. This review discusses potential reasons why IGF-I R targeted therapy fails to inhibit growth of human cancers. It has become clear that intracellular signaling pathways are highly interconnected and complex instead of being linear and simple. One of the most potent candidates for failure of IGF-IR targeted therapy is the insulin receptor isoform A (IR-A). Activation of the IR-A by insulin-like growth factor-II (IGF-II) bypasses the IGF-IR and its inhibition. Another factor may be that anti-cancer treatment may reduce IGF-IR expression. IGF-IR blocking drugs may also induce hyperglycemia and hyperinsulinemia, which may further stimulate cell growth. In addition, circulating IGF-IRs may reduce therapeutic effects of IGF-IR targeted therapy. Nevertheless, it is still possible that the IGF-IR may be a useful adjuvant or secondary target for the treatment of human cancers. Development of functional inhibitors that affect the IGF-IR and IR-A may be necessary to overcome resistance and to make IGF-IR targeted therapy successful. Drugs that modify alternative downstream effects of the IGF-IR, so called “biasing agonists,” should also be considered. PMID:25566194

  10. IRS Data Retrieval Tool 2012-2013 FAFSA

    E-print Network

    Russell, Lynn

    1 IRS Data Retrieval Tool 2012-2013 FAFSA Financial Aid Office University of California, San Diego #12;2 What is the IRS Data Retrieval Tool? · The IRS Retrieval Tool gives FAFSA applicants and parents the ability to transfer their data from the IRS to the FAFSA · The Retrieval Tool saves time and increases

  11. Synthesis of cellulose triacetate from cotton cellulose by using NIS as a catalyst under mild reaction conditions.

    PubMed

    El Nemr, Ahmed; Ragab, Safaa; El Sikaily, Amany; Khaled, Azza

    2015-10-01

    This research discusses the acetylation of cotton cellulose with acetic anhydride without solvents. The acetylation was done in the presence of different amounts of N-Iodosuccinimide (NIS) as a catalyst; this took place under mild reaction conditions. The extent of acetylation was measured by the weight percent gain (WPG) that varied from 24.71 to 71.83%. Cotton cellulose acetates, with the degree of substitution (DS) that ranged from 0.89 to 2.84, were prepared in one step. The cellulose triacetate, with a degree of substitution (DS) 2.84, was obtained. The WPG and DS were easily controlled by changing the reaction duration (1-5h), and the concentration of the catalyst (0.05g, 0.075g and 0.10g for 1g of cellulose) in 25ml of acetic anhydride. NIS was recognized as a novel and more successful catalyst for the acetylation of hydroxyl groups in cotton cellulose. Formation of the acetates and the calculation of the degree of substitution were performed by FT-IR, Raman, and (1)H NMR. PMID:26076599

  12. Optimization of PtIr electrocatalyst for PEM URFC

    Microsoft Academic Search

    Sung-Dae Yim; Gu-Gon Park; Young-Jun Sohn; Won-Yong Lee; Young-Gi Yoon; Tae-Hyun Yang; Sukkee Um; Sang-Phil Yu; Chang-Soo Kim

    2005-01-01

    For the fabrication of high-efficient bifunctional electrocatalyst of oxygen electrode, several electrocatalysts were prepared and tested on the URFC performance including both fuel cell and water electrolysis in a single cell URFC system. The catalysts revealed fuel cell performance in the order of Pt black>PtIr>PtRuOx>PtRu?PtRuIr>PtIrOx and water electrolysis performance in the order of PtIr?PtIrOx>PtRu>PtRuIr>PtRuOx?Pt black. Considering both results PtIr showed

  13. Narcissus analysis for cooled staring IR system

    NASA Astrophysics Data System (ADS)

    He, Feng-Yun; Cui, Ji-Cheng; Feng, Shu-Long; Zhang, Xin

    2007-12-01

    Narcissus can have a deleterious effect on image quality for cooled infrared imaging systems. Therefore, analysis of narcissus is important for designing both scanning and staring optics. Narcissus is generally assumed to be negligible in staring IR optical designs because the shading effects can be removed by calibration of the detector array data. However, the calibration usually decreases sensitiveness of the system and Narcissus variation may be noticeable for sensors when the conditions changes as follows: 1. warming and cooling the optical housing, 2. zooming optical elements, 3. movement of lenses for focus. In that case, it will result in shading and other image defects even after calibration. To minimize these effects, narcissus should be assessed and controlled during the design of staring array IR system. We provided a direct and fast method for analyzing the narcissus variation in the presence of software such as LightTools, TracePro and ASAP, and proposed the principles in optical design of staring IR systems to reduce narcissus. A cooled staring IR system with serious narcissus was estimated and reoptimized. Narcissus analysis of this IR system confirmed the efficiency of the analysis method.

  14. Cross Sections of Proton Induced Nuclear Reactions on Iridium

    SciTech Connect

    Tarkanyi, F.; Ditroi, F.; Takacs, S.; Kiraly, B. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), 4026 Debrecen (Hungary); Hermanne, A. [Cyclotron Laboratory, Vrije Universiteit Brussel, 1090 Brussels (Belgium); Uddin, M.S.; Hagiwara, M.; Baba, M. [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Shubin, Yu.N.; Dityuk, A.I. [Institute of Physics and Power Engineering, Obninsk 249020 (Russian Federation)

    2005-05-24

    Excitation functions of the reactions natIr(p,xn)188,189,191Pt and natIr(p,x)186,187,188,189,190,192Ir were measured up to 70 MeV for practical applications. The measured experimental data were compared with the earlier results and analyzed using theoretical calculations based on the model code Alice-IPPE, The new experimental data show significant deviations from the earlier experimental results. Good agreement was found on average with the model calculation. Applications are also discussed.

  15. Automatic NMR-Based Identification of Chemical Reaction Types in Mixtures of Co-Occurring Reactions

    PubMed Central

    Latino, Diogo A. R. S.; Aires-de-Sousa, João

    2014-01-01

    The combination of chemoinformatics approaches with NMR techniques and the increasing availability of data allow the resolution of problems far beyond the original application of NMR in structure elucidation/verification. The diversity of applications can range from process monitoring, metabolic profiling, authentication of products, to quality control. An application related to the automatic analysis of complex mixtures concerns mixtures of chemical reactions. We encoded mixtures of chemical reactions with the difference between the 1H NMR spectra of the products and the reactants. All the signals arising from all the reactants of the co-occurring reactions were taken together (a simulated spectrum of the mixture of reactants) and the same was done for products. The difference spectrum is taken as the representation of the mixture of chemical reactions. A data set of 181 chemical reactions was used, each reaction manually assigned to one of 6 types. From this dataset, we simulated mixtures where two reactions of different types would occur simultaneously. Automatic learning methods were trained to classify the reactions occurring in a mixture from the 1H NMR-based descriptor of the mixture. Unsupervised learning methods (self-organizing maps) produced a reasonable clustering of the mixtures by reaction type, and allowed the correct classification of 80% and 63% of the mixtures in two independent test sets of different similarity to the training set. With random forests (RF), the percentage of correct classifications was increased to 99% and 80% for the same test sets. The RF probability associated to the predictions yielded a robust indication of their reliability. This study demonstrates the possibility of applying machine learning methods to automatically identify types of co-occurring chemical reactions from NMR data. Using no explicit structural information about the reactions participants, reaction elucidation is performed without structure elucidation of the molecules in the mixtures. PMID:24551112

  16. Automatic NMR-based identification of chemical reaction types in mixtures of co-occurring reactions.

    PubMed

    Latino, Diogo A R S; Aires-de-Sousa, João

    2014-01-01

    The combination of chemoinformatics approaches with NMR techniques and the increasing availability of data allow the resolution of problems far beyond the original application of NMR in structure elucidation/verification. The diversity of applications can range from process monitoring, metabolic profiling, authentication of products, to quality control. An application related to the automatic analysis of complex mixtures concerns mixtures of chemical reactions. We encoded mixtures of chemical reactions with the difference between the (1)H NMR spectra of the products and the reactants. All the signals arising from all the reactants of the co-occurring reactions were taken together (a simulated spectrum of the mixture of reactants) and the same was done for products. The difference spectrum is taken as the representation of the mixture of chemical reactions. A data set of 181 chemical reactions was used, each reaction manually assigned to one of 6 types. From this dataset, we simulated mixtures where two reactions of different types would occur simultaneously. Automatic learning methods were trained to classify the reactions occurring in a mixture from the (1)H NMR-based descriptor of the mixture. Unsupervised learning methods (self-organizing maps) produced a reasonable clustering of the mixtures by reaction type, and allowed the correct classification of 80% and 63% of the mixtures in two independent test sets of different similarity to the training set. With random forests (RF), the percentage of correct classifications was increased to 99% and 80% for the same test sets. The RF probability associated to the predictions yielded a robust indication of their reliability. This study demonstrates the possibility of applying machine learning methods to automatically identify types of co-occurring chemical reactions from NMR data. Using no explicit structural information about the reactions participants, reaction elucidation is performed without structure elucidation of the molecules in the mixtures. PMID:24551112

  17. Properties of the {pi}h{sub 11/2} band in the stable nucleus {sup 193}Ir

    SciTech Connect

    Fang, Y. D.; Zhang, Y. H.; Zhou, X. H.; Liu, M. L.; Wang, J. G.; Ma, F.; Guo, Y. X.; Fang, F. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Shi, Y.; Xu, F. R. [Department of Technical Physics and MOE Key Laboratory, Peking University, Beijing 100871 (China); Gao, B. S.; Wang, S. C.; Li, S. C.; Yan, X. L.; He, L.; Wang, Z. G. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 000049 (China); Wu, X. G.; He, C. Y.; Zheng, Y.; Wang, Z. M. [China Institute of Atomic Energy, Beijing 102413 (China)

    2011-05-15

    Excited states in the stable nucleus {sup 193}Ir have been investigated through an in-beam {gamma}-ray spectroscopic technique following the {sup 192}Os({sup 7}Li, {alpha}2n) reaction at a beam energy of 44 MeV. A level scheme built on the {pi}h{sub 11/2} isomer has been extended to high-spin states using eleven newly observed {gamma} transitions. The {pi}h{sub 11/2} band is proposed to be formed by coupling an h{sub 11/2} proton to a core with large triaxial deformation. Three-quasiparticle states are suggested in {sup 193}Ir on referring to the similar states in {sup 187}Ir. The features of signature splitting in the {pi}h{sub 11/2} bands of {sup 187-193}Ir are discussed with the help of total Routhian surface calculations.

  18. ALTAIR: automatic location tracking system using active IR-tag

    Microsoft Academic Search

    Muneyuki Sakata; Yoshihiro Yasumuro; Masataka Imura; Yoshitsugu Manabe; Kunihiro Chihara

    2003-01-01

    This paper proposes a new location-awareness system ALTAIR (automatic location tracking system using active IR-tag) that automatically detects and tracks the location of the mobile PC (personal computer) users. IR-tag (infrared) is a small electrical device to indicate its location by emitting IR light and reliable detected by a camera with IR-pass filter. IR-tag is installed on a mobile PC,

  19. An eco-friendly procedure for the efficient synthesis of arylidinemalononitriles and 4,4?-(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ols) in aqueous media

    Microsoft Academic Search

    Moustafa A. Gouda; Ameen A. Abu-Hashem

    2012-01-01

    Commercially available lithium hydroxide monohydrate (LiOH·H2O) was found to be a novel “dual activation” catalyst for Knoevenagel condensation between malononitrile (1) or 3-methyl 1-phenyl-1H-pyrazol-5-(4H)-one (6) with aromatic aldehydes 2a–e leading to an efficient and easy synthesis of arylidenemalononitriles 3a–d and 4,4?-(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ols) 7a–c in short times. The reaction of aryl aldehydes with malononitrile afforded excellent yields after 1–6 min in aqueous

  20. Ultrasound-assisted one-pot, three-component synthesis of spiro[indoline-3,4?-pyrazolo[3,4- b]pyridine]-2,6?(1? H)-diones in water

    Microsoft Academic Search

    Ayoob Bazgir; Somayeh Ahadi; Ramin Ghahremanzadeh; Hamid Reza Khavasi; Peiman Mirzaei

    2010-01-01

    A simple, facile, efficient and three-component procedure for the synthesis of spiro[indoline-3,4?-pyrazolo[3,4-b]pyridine]-2,6?(1?H)-diones by the reaction of 4-hydroxycumarin, isatins and 1H-pyrazol-5-amines in water under ultrasonic irradiation is reported. The advantages of this method are the use of an inexpensive and readily available catalyst, easy work-up, good yields, and the use of water as a solvent that is considered to be relatively

  1. Ultrasound-assisted one-pot, three-component synthesis of spiro[indoline-3,4'-pyrazolo[3,4-b]pyridine]-2,6'(1'H)-diones in water.

    PubMed

    Bazgir, Ayoob; Ahadi, Somayeh; Ghahremanzadeh, Ramin; Khavasi, Hamid Reza; Mirzaei, Peiman

    2010-02-01

    A simple, facile, efficient and three-component procedure for the synthesis of spiro[indoline-3,4'-pyrazolo[3,4-b]pyridine]-2,6'(1'H)-diones by the reaction of 4-hydroxycumarin, isatins and 1H-pyrazol-5-amines in water under ultrasonic irradiation is reported. The advantages of this method are the use of an inexpensive and readily available catalyst, easy work-up, good yields, and the use of water as a solvent that is considered to be relatively environmentally benign. PMID:19836289

  2. Magnesium Silicate Dissolution Investigated by 29Si MAS, 1H-29Si CP MAS, 25Mg QCPMG, and 1H-25Mg CP QCPMG NMR

    SciTech Connect

    Davis, Michael C.; Brouwer, William J.; Wesolowski, David J.; Anovitz, Lawrence M.; Lipton, Andrew S.; Mueller, Karl T.

    2009-08-01

    Olivine has been the subject of frequent investigation in the earth sciences because of its simple structure and rapid dissolution kinetics. Several studies have observed a preferential release of magnesium with respect to silica during weathering under acidic conditions, which has been correlated to the formation of a silicon rich leached layer. While leached layer formation has been inferred through the changing solution chemistry, a thorough spectroscopic investigation of olivine reacted under acidic conditions has not been conducted. In particular, the fate of magnesium in the system is not understood and spectroscopic interrogations through nuclear magnetic resonance can elucidate the changing magnesium coordination and bonding environment. In this study, we combine analysis of the changing solution chemistry with advanced spectroscopic techniques (29Si MAS, 1H-29Si CP MAS, 25Mg QCPMG, and 1H-25Mg 2 CP QCPMG NMR) to probe leached layer formation and possible secondary phase precipitation during the dissolution of forsterite at 150 oC.

  3. IR signature management for the modern navy

    NASA Astrophysics Data System (ADS)

    Vaitekunas, David A.; Kim, Yoonsik

    2013-06-01

    A methodology for analysing the infrared (IR) signature and susceptibility of naval platforms using ShipIR/NTCS was presented by Vaitekunas (2010). This paper provides three key improvements: use of a larger climatic data set (N=100), a new target sub-image algorithm eliminating false detections from pixel-aliasing at the horizon, and a new seeker model interfacing with a line-by-line background clutter model. Existing commercial stealth technologies (exhaust stack suppression, low solar absorptive paints, extended hull film-cooling) are re-analysed using the new models and methods to produce a more rigorous and comprehensive analysis of their effectiveness based on the statistics of reduction in IR susceptibility. These methods and results combined with the cost of each stealth option should allow platform managers to select an appropriate level of infrared suppression and establish the design criteria for a new ship.

  4. Developments in IRS Multi-Mode Waveforms

    NASA Astrophysics Data System (ADS)

    Kelly, Bernard; Baker, John

    2013-04-01

    The IRS picture [Baker et al. PRD 78:044046 (2008); Kelly et al. 84:084009 (2011)] visualises black-hole-binary late-inspiral/merger/ringdown gravitational waveforms as being generated by a single rotating source, with most important waveform angular modes being locked in phase through merger into ringdown. This led to the development of late-merger/ringdown waveform templates for the dominant modes of the binary for nonspinning black holes, and for holes with aligned (non-precessing) spins. During development of the IRS model, it was noticed that certain subdominant modes --- most notably the (3,2) mode --- suffered from non-monotonic bumps in both frequency and amplitude, indicative of some kind of mode-mixing behavior. We report on the resolution of this ``bumpy'' behavior, and of consequent developments to the IRS waveforms across multiple significant angular modes.

  5. Tunable mid IR plasmon in GZO nanocrystals.

    PubMed

    Hamza, M K; Bluet, J-M; Masenelli-Varlot, K; Canut, B; Boisron, O; Melinon, P; Masenelli, B

    2015-07-28

    Degenerate metal oxide nanoparticles are promising systems to expand the significant achievements of plasmonics into the infrared (IR) range. Among the possible candidates, Ga-doped ZnO nanocrystals are particularly suited for mid IR, considering their wide range of possible doping levels and thus of plasmon tuning. In the present work, we report on the tunable mid IR plasmon induced in degenerate Ga-doped ZnO nanocrystals. The nanocrystals are produced by a plasma expansion and exhibit unprotected surfaces. Tuning the Ga concentration allows tuning the localized surface plasmon resonance. Moreover, the plasmon resonance is characterized by a large damping. By comparing the plasmon of nanocrystal assemblies to that of nanoparticles dispersed in an alumina matrix, we investigate the possible origins of such damping. We demonstrate that it partially results from the self-organization of the naked particles and also from intrinsic inhomogeneity of dopants. PMID:26111776

  6. Recent Developments in Sonic IR Imaging

    NASA Astrophysics Data System (ADS)

    Han, Xiaoyan; Favro, L. D.; Thomas, R. L.

    2003-03-01

    We describe recent developments in sonic infrared (IR) imaging. The sonic IR imaging NDE technique uses a single short pulse of sound to cause cracks to heat up and become visible in the infrared. Results of recent experiments on metal aircraft structures and composite test samples with natural and simulated defects are presented in this paper. Examples of defects in metals include cracks originating under fasteners and cracks in mechanical parts. Examples of defects in composites include fatigue cracks, pillow inserts, pull-tab disbonds, skin-to-core disbonds, etc. Both 20kHz and 40kHz ultrasonic excitation sources were used for studying the frequency effect. Vibrational behavior of surfaces near the defects was monitored and correlated with the IR signals.

  7. Fiber Delivery of mid-IR lasers

    SciTech Connect

    Kriesel, J.M.; Gat, N.; Bernacki, Bruce E.; Myers, Tanya L.; Bledt, Carlos M.; Harrington, James P.

    2011-08-24

    Fiber optics for the visible to near infrared (NIR) wavelength regimes (i.e. = 0.42 {mu}m) have proven to be extremely useful for a myriad of applications such as telecommunications, illumination, and sensors because they enable convenient, compact, and remote delivery of laser beams. Similarly, there is a need for fiber optics operating at longer wavelengths. For example, systems operating in the mid-IR regime (i.e., = 314 {mu}m) are being developed to detect trace molecular species with far-reaching applications, such as detecting explosives on surfaces, pollutants in the environment, and biomarkers in the breath of a patient. Furthermore, with the increasing availability of quantum cascade lasers (QCLs) which are semiconductor lasers that operate in the mid-IR regime additional uses are rapidly being developed. Here, we describe the development of hollow-core fibers for delivery of high-quality mid-IR laser beams across a broad spectral range.

  8. Analysis of illegally manufactured formulations of tadalafil (Cialis ®) by 1H NMR, 2D DOSY 1H NMR and Raman spectroscopy

    Microsoft Academic Search

    Saleh Trefi; Corinne Routaboul; Saleh Hamieh; Véronique Gilard; Myriam Malet-Martino; Robert Martino

    2008-01-01

    Counterfeit and\\/or imitation medicines are becoming a major health problem not only in developing countries but also in wealthier countries. The need of new and easy analytical methods for quality control of drugs is essential. We describe the use of Raman spectroscopy, 1H nuclear magnetic resonance (NMR) and 2D diffusion-ordered spectroscopy (DOSY) NMR to analyse genuine Cialis® and seven illegally

  9. A practical method for stereospecific assignments of gamma- and delta-methylene hydrogens via estimation of vicinal 1H-1H coupling constants.

    PubMed

    Cai, M; Liu, J; Gong, Y; Krishnamoorthi, R

    1995-05-01

    Stereospecific assignments are made for gamma- and delta-methylene hydrogens in a protein by means of estimation of vicinal 1H-1H spin-spin coupling constants from a short-mixing-time TOCSY experiment. 3J alpha beta coupling constants, as measured from a P.E. COSY map, are shown to be well correlated with alpha-beta cross-peak intensities of a short-mixing-time (10 ms) TOCSY map. The procedure is illustrated by application to a trypsin-inhibitor protein (M(r) approximately 7 Kd). Thus, gamma-methylene hydrogens of isoleucine residues have been stereospecifically assigned on the basis of 3J beta gamma 1H-1H coupling patterns and intraresidue cross-peak intensities in a NOESY map; gamma-hydrogens of other residues, such as lysine and arginine, have been stereospecifically assigned solely on the basis of cross-peak intensity patterns resulting from coupling of two beta-hydrogens to two gamma-hydrogens, and in conjunction with stereospecific assignments of beta-methylene hydrogens. However, intraresidue NOE intensities are needed if one or two pairs of coupling constants cannot be estimated because of cross peaks either overlapping or occurring proximal to the diagonal. The delta-methylene hydrogens have been stereospecifically assigned on the basis of coupling between two gamma-hydrogens and two delta-hydrogens, in combination with stereospecific assignments of gamma-hydrogens. Stereospecific assignments of side chains should contribute to the overall precision and accuracy of NMR-determined three-dimensional solution structures of proteins. PMID:7599951

  10. Synthesis, spectroscopic and structural characterization of 5-benzoyl-4-phenyl-2-methylthio-1H-pyrimidine with theoretical calculations using density functional theory

    NASA Astrophysics Data System (ADS)

    ?nkaya, Ersin; Dinçer, Muharrem; ?ahan, Emine; Y?ld?r?m, ?smail

    2013-10-01

    In this paper, we will report a combined experimental and theoretical investigation of the molecular structure and spectroscopic parameters (FT-IR, 1H NMR, 13C NMR) of 5-benzoyl-4-phenyl-2-methylthio-1H-pyrimidine. The compound crystallizes in the triclinic space group P-1 with Z = 2. The molecular geometry was also optimized using density functional theory (DFT/B3LYP) method with the 6-311G(d,p) and 6-311++G(d,p) basis sets in ground state and compared with the experimental data. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential (ESP). Also, non-linear optical properties of the title compound were performed at B3LYP/6-311++G(d,p) level. The theoretical results showed an excellent agreement with the experimental values.

  11. Molecular structure of 4-benzoyl-3-ethylcarboxylate 1-(4-methoxyphenyl)-5-phenyl-1H-pyrazole: A combined experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    ?nkaya, Ersin; Dinçer, Muharrem; Korkusuz, Elif; Y?ld?r?m, ?smail

    2012-04-01

    The title molecule, 4-benzoyl-3-ethylcarboxylate 1-(4-methoxyphenyl)-5-phenyl-1H-pyrazole, (C26H22N2O4), was synthesized and characterized by IR-NMR spectroscopy and single-crystal X-ray diffraction. In addition to the molecular geometry from X-ray experiment, the molecular geometry, vibrational frequencies and gauge-independent atomic orbital (GIAO) 1H and 13C NMR chemical shift values of the title compound in the ground state have been calculated using the spin-restricted Hartree-Fock (HF) and density functional theory (DFT/B3LYP) method with the 6-31G (d, p) basis set, and compared with the experimental data. To determine conformational flexibility, molecular energy profile of the tittle compound was obtained by semi-empirical (AM1) with respect to selected degree of torsional freedom, which was varied from -180° to +180° in steps 10°. Besides, molecular electrostatic potential (MEP) distribution, frontier molecular orbitals (FMOs) and thermodynamic properties of the title molecule were investigated by theoretical calculations at the B3LYP/6-31G (d, p) level.

  12. Crystal structure and DFT calculations of 5-(4-Chlorophenyl)-1-(6-methoxypyridazin-3-yl)-1H-pyrazole-3-carboxylic acid

    NASA Astrophysics Data System (ADS)

    Ala?alvar, Can; Soylu, Mustafa Serkan; Ünver, Hüseyin; Ocak ?skeleli, Nazan; Yildiz, Mustafa; Çiftçi, Murat; Bano?lu, Erden

    2014-11-01

    The title compound, 5-(4-Chlorophenyl)-1-(6-methoxypyridazin-3-yl)-1H-pyrazole-3-carboxylic acid, has been characterized by using elemental analysis, MS, FT-IR, 1H NMR and 13C NMR spectroscopic, and crystallographic techniques. The title compound crystallizes in the triclinic space group P-1 with a = 9.612(1), b = 9.894(1), c = 17.380(1) Å, ? = 90.213(5)°, ? = 104.99(1)°, ? = 111.072(5)°, V = 1481.3(2) Å3 and Dx = 1.483 g cm-3 respectively. The structure of the compound has also been examined by using quantum chemical methods. The molecular geometry and vibrational frequencies of monomeric and dimeric form of the title compound in the ground state have been calculated by using the B3LYP/6-31G(d,p) level of the theory. The calculated results show that the optimized geometry and the theoretical vibration frequencies of the dimeric form are good agreement with experimental data. In addition, HOMO-LUMO energy gap, molecular electrostatic potential map, thermodynamic properties of the title compound were performed at B3LYP/6-31G(d,p) level of theory.

  13. Synthesis, spectroscopic characterization and quantum chemical computational studies on 1-acetyl-3,5-di(4-methylphenyl)-1H-pyrazole

    NASA Astrophysics Data System (ADS)

    ?nkaya, Ersin; Dinçer, Muharrem; Korkusuz, Elif; Y?ld?r?m, ?smail; Büyükgüngör, Orhan

    2012-11-01

    The pyrazole compound 1-acetyl-3,5-di(4-methylphenyl)-1H-pyrazole, (C19H18N2O), was characterized by X-ray single crystal diffraction technique, IR-NMR spectroscopy and quantum chemical computational methods as both experimental and theoretically. The compound crystallizes in the monoclinic space group C 2/c with a = 32.5334 (1) Å, b = 5.8060 (1) Å, c = 23.6519 (8) Å, ? = 134.572 (2)°, and Z = 8. The molecular geometry was also optimized using the Hartree-Fock (HF) and density functional theory (DFT/B3LYP) methods with the 6-311G(d,p) basis set and compared with the experimental data. To determine conformational flexibility, molecular energy profile of the tittle compound was obtained by semi-empirical (AM1) with respect to selected degree of torsional freedom, which was varied from -180° to +180° in steps 10°. From the optimized geometry of the molecule, vibrational frequencies, gauge-independent atomic orbital (GIAO) 1H and 13C NMR chemical shift values, molecular electrostatic potential (MEP) distribution, non-linear optical properties, frontier molecular orbitals (FMOs) of the title compound have been calculated in the ground state theoretically. The theoretical result showed good agreement with the experimental values.

  14. Synthesis, DFT calculations and cytotoxic investigation of platinum complexes with 3-thiolanespiro-5?-hydantoin and 4-thio-1H-tetrahydropyranespiro-5?-hydantoin

    NASA Astrophysics Data System (ADS)

    Bakalova, Adriana; Buyukliev, Rossen; Momekov, Georgi

    2015-07-01

    Two organic compounds - 3-thiolanespiro-5?-hydantoin, 4-thio-1H-tetrahydropyranespiro-5?-hydantoin and four new Pt(II) and Pt(IV) complexes with general formulas cis-[Pt(L)2Cl2] and cis-[Pt(L)2Cl4] were synthesized. The obtained compounds were characterized by elemental analysis, IR, 1H, 13C NMR spectroscopy. The hybrid DFT calculations were used for optimization of the structure geometries of the ligand (L1) and its Pt(II) complex (1). The calculated structural parameters such as bond lengths and angles are in good agreement with the experimental data for similar hydantoins and their platinum complexes. The obtained results showed that the geometry of the complex (1) is plane square and the bounding of the L1 with platinum ion is realized by sulfur atom from thiolane ring. The complexes were tested for cytotoxicity in vitro on four human tumor cell lines. The tested compounds exerted concentration-dependent cytotoxic effects against some of the tumor cell lines.

  15. Vibrational spectra and electronic structure of 3-((1H-pyrrol-1-yl) methyl) naphthalen-2-ol - A computational insight on antioxidant active Mannich base

    NASA Astrophysics Data System (ADS)

    Boobalan, Maria susai; Tamilvendan, D.; Amaladasan, M.; Ramalingam, S.; Venkatesa Prabhu, G.; Bououdina, M.

    2015-02-01

    The 3-((1H-pyrrol-1-yl) methyl) naphthalen-2-ol (IFTN) is a class of synthesized organic Mannich base compound having antioxidant property of biological importance. A meticulous normal mode vibrational analysis has been carried out by comparing and contrasting the experimentally recorded FT-IR and FT-Raman spectra with simulated spectra of IFTN. Similarly the calculated 1H and 13C NMR of IFTN were correlated with experimental findings to understand the shielding and deshielding nature hold in it. The following other electronic structure properties were calculated such as equilibrium geometrical parameters, natural bond orbital analysis (NBO), frontier molecular orbital (FMO) characterization, statistical thermochemical properties against a range of temperatures and molecular electrostatic potential (MEP) imprint was carried out along with various charges such as APT, ESP, Hirshfeld, natural and Mulliken. All these predicted properties unlock the nature of total behavior of IFTN in various dimensions. These could be Lewis, non-Lewis interaction along with their respective energies, contribution of fragmented moieties for various orders of HOMO and LUMO, temperature consequences on enthalpy, entropy, and heat capacity. In addition, the MEP leads to find electrophilic, nucleophilic reactive sites on IFTN molecular surface. The entire computational calculations has been made on HF/6-31+G/6-311++G(d,p) and B3LYP/6-31+G/6-311++G(d,p) model chemistries. A complete electronic structure observation has been achieved by this theoretical analysis.

  16. Experimental and DFT study on a newly synthesized ethyl 2-cyano-3-[5-(phenyl-hydrazonomethyl)-1H-pyrrol-2-yl]-acrylate

    NASA Astrophysics Data System (ADS)

    Rawat, Poonam; Singh, R. N.

    2015-02-01

    A newly synthesized ethyl 2-cyano-3-[5-(phenyl-hydrazonomethyl)-1H-pyrrol-2-yl]-acrylate (ECPHPA) has been characterized by experimental measurements. The theoretically calculated results are in accordance with the experimental studies. All calculations have been performed using B3LY/6-31G(d,p) basis set. The oscillatory strength (f) and wavelength of various electronic excitations show ? ? ?? nature of transitions. Natural bond orbital (NBO) analysis shows intramolecular conjugative/hyperconjugative interactions within the studied molecule. The result of hydrogen bonding is obvious in 1H NMR, FT-IR and NBO analyses as down field chemical shift, vibrational red shift and ?1(C8sbnd N9) ? ??(N1sbnd H24) interaction, respectively. Global electrophilicity index (? = 4.80 eV) shows that ECPHPA is a strong electrophile and local reactivity descriptors indicate have reactive sites within molecule and undergo for the formation of various heterocyclic compounds. The first hyperpolarizability (?0) computed found to be 35.76 × 10-30 esu, evaluate the suitability of compound for non-linear optical (NLO) response.

  17. Advanced ROICs design for cooled IR detectors

    NASA Astrophysics Data System (ADS)

    Zécri, Michel; Maillart, Patrick; Sanson, Eric; Decaens, Gilbert; Lefoul, Xavier; Baud, Laurent

    2008-04-01

    The CMOS silicon focal plan array technologies hybridized with infrared detectors materials allow to cover a wide range of applications in the field of space, airborne and grounded-based imaging. Regarding other industries which are also using embedded systems, the requirements of such sensor assembly can be seen as very similar; high reliability, low weight, low power, radiation hardness for space applications and cost reduction. Comparing to CCDs technology, excepted the fact that CMOS fabrication uses standard commercial semiconductor foundry, the interest of this technology used in cooled IR sensors is its capability to operate in a wide range of temperature from 300K to cryogenic with a high density of integration and keeping at the same time good performances in term of frequency, noise and power consumption. The CMOS technology roadmap predict aggressive scaling down of device size, transistor threshold voltage, oxide and metal thicknesses to meet the growing demands for higher levels of integration and performance. At the same time infrared detectors manufacturing process is developing IR materials with a tunable cut-off wavelength capable to cover bandwidths from visible to 20?m. The requirements of third generation IR detectors are driving to scaling down the pixel pitch, to develop IR materials with high uniformity on larger formats, to develop Avalanche Photo Diodes (APD) and dual band technologies. These needs in IR detectors technologies developments associated to CMOS technology, used as a readout element, are offering new capabilities and new opportunities for cooled infrared FPAs. The exponential increase of new functionalities on chip, like the active 2D and 3D imaging, the on chip analog to digital conversion, the signal processing on chip, the bicolor, the dual band and DTI (Double Time Integration) mode ...is aiming to enlarge the field of application for cooled IR FPAs challenging by the way the design activity.

  18. Asymmetric synthesis of novel (1H-benzo[d]imidazol -2-ylthio)- and (di-n-butylamino-2-ylthio)acetamides.

    PubMed

    ?aczkowski, Krzysztof Z

    2013-01-01

    Asymmetric synthesis of novel (1H-benzo[d]imidazol-2-ylthio)- and (di-n-butylamino)acetamides is described. The o-nitrobenzyl oxime ethers were reduced with borane in the presence of oxazaborolidenes derived from norephedrine or diphenylvalinol and diphenylphosphinic amide was reduced with modified sodium tetrahydroborate catalyzed with beta-ketoiminato cobalt(II) complex to the corresponding amines with high yields and moderate enantiomeric excess. Reaction of amines with 2-chloroacetyl chloride and next with thiobenzimidazole or n-dibutylamine gave corresponding products with high yields. PMID:23614279

  19. Synthesis and antiviral activity of 4,4?-(arylmethylene)bis(1 H-pyrazol-5-ols) against peste des petits ruminant virus (PPRV)

    Microsoft Academic Search

    Kuppusamy Sujatha; Gnanamani Shanthi; Nagarajan Panneer Selvam; Seeralan Manoharan; Paramasivan T. Perumal; Melani Rajendran

    2009-01-01

    An efficient and eco-friendly method for the synthesis of 4,4?-(arylmethylene)bis(1H-pyrazol-5-ols) has been accomplished by tandem Knoevenagel–Michael reaction of two equivalents of 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one with various aromatic aldehydes catalyzed by ceric ammonium nitrate (CAN) in water. All the synthesized compounds 3a–j were evaluated for in vitro antiviral activity against peste des petits ruminant virus (PPRV). Compound 3i emerged as the most interesting

  20. 1,3-Bis(4-meth­oxy­benz­yl)-6-methyl­pyrimidine-2,4(1H,3H)-dione

    PubMed Central

    Li, Gong-Chun; Zhang, Li-Ke; Ju, Zhi-Yu; Yang, Feng-Ling

    2010-01-01

    The title compound, C21H22N2O4, was prepared by reaction of 6-methyl­pyrimidine-2,4(1H,3H)-dione and 1-chloro­methyl-4-meth­oxy­benzene. In the title mol­ecule, the central pyrimidine ring forms dihedral angles of 62.16?(4) and 69.77?(3)° with the two benzene rings. In the crystal, weak inter­molecular C—H?O hydrogen bonds link the mol­ecules into chains. PMID:21588055

  1. Gold-catalyzed cycloisomerization of 1,6-diyne carbonates and esters to 2,4a-dihydro-1H-fluorenes.

    PubMed

    Rao, Weidong; Koh, Ming Joo; Li, Dan; Hirao, Hajime; Chan, Philip Wai Hong

    2013-05-29

    A synthetic method to prepare 2,4a-dihydro-1H-fluorenes efficiently from gold(I)-catalyzed 1,2-acyloxy migration/cyclopropenation/Nazarov cyclization of 1,6-diyne carbonates and esters is described. The suggested reaction pathway provides rare examples of [2,3]-sigmatropic rearrangement in this class of compounds as well as the involvement of an in situ formed cyclopropene intermediate in gold catalysis. Experimental and ONIOM(QM:QM') [our own n-layered integrated molecular orbital and molecular mechanics(quantum mechanics:quantum mechanics')] computational studies based on the proposed Au carbenoid species provide insight into this unique selectivity. PMID:23627597

  2. Higgs phenomenology in Type-I 2HDM with U(1) H Higgs gauge symmetry

    NASA Astrophysics Data System (ADS)

    Ko, P.; Omura, Yuji; Yu, Chaehyun

    2014-01-01

    It is well known that generic two-Higgs-doublet models (2HDMs) suffer from potentially large Higgs-mediated flavor-changing neutral current (FCNC) problem, unless additional symmetries are imposed on the Higgs fields thereby respecting the Natural Flavor Conservation Criterion (NFC) by Glashow and Weinberg. A common way to respect the NFC is to impose Z 2 symmetry which is softly broken by a dim-2 operator. Another new way is to introduce local U(1) H Higgs flavor symmetry that distinguishes one Higgs doublet from the other. In this paper, we consider the Higgs phenomenology in Type-I 2HDMs with the U(1) H symmetry with the simplest U(1) H assignments that the SM fermions are all neutral under U(1) H , and we make detailed comparison with the ordinary Type-I 2HDM. After imposing various constraints such as vacuum stability and perturbativity as well as the electroweak precision observables and collider search bounds on charged Higgs boson, we find that the allowed Higgs signal strengths in our model are much broader than those in the ordinary Type-I 2HDM, because of newly introduced U(1) H -charged singlet scalar and U(1) H gauge boson. Still the ATLAS data on gg ? h ? ?? cannot be accommodated. Our model could be distinguished from the ordinary 2HDM with the Z 2 symmetry in a certain parameter region and some channels. If the couplings of the new boson turn out to be close to those in the SM, it would be essential to search for extra U(1) H gauge boson and/or one more neutral scalar boson to distinguish two models.

  3. Kinetics of elementary atom and radical reactions. Progress report, December 1, 1981-November 30, 1982

    SciTech Connect

    Gordon, R J

    1982-08-02

    Research projects discussed include: the branching ratio for abstraction vs. exchange in the reaction D + HCl; kinetics of O + H/sub 2/; energy storage in polyatomic molecules; and optoacoustic measurements of ir absorption and relaxation in large molecules. (GHT)

  4. Platinum Monolayer Electrocatalysts for O2 Reduction: Pt Monolayer on Carbon-Supported PdIr Nanoparticles

    SciTech Connect

    Vukmirovic, M.B.; Knupp, S.L. Haldar, P.; Herron, J.A.: Mavrikakis, M.; Adzic, R.R.

    2010-11-01

    The kinetics of oxygen reduction was investigated in acid solutions on Pt monolayers deposited on modified carbon-supported PdIr nanoparticles using the rotating disk-electrode technique. Iridium is introduced into the Pd substrate in order to fine-tune the Pt-Pd interactions and to improve Pd stability under operating conditions of the fuel cell. The kinetics of the oxygen reduction reaction shows enhancement with the Pt monolayer on the PdIr nanoparticle surfaces in comparison with the reaction on Pt/C and Pt monolayer on Pd/C nanoparticles. The electrochemical measurements suggest that reduced oxidation of Pt monolayer on PdIr/C compared to Pt/C and Pt monolayer on Pd/C is the cause of enhanced activity. Besides a ligand effect induced to the Pt surface by the presence of PdIr in the second sublayer of the nanoparticle, as suggested by our density functional theory analysis, Ir also leads to a Pd skin contraction, so the Pt monolayer on PdIr/C is compressed more than on Pd/C. Both effects lead to further weakening of the Pt-OH interaction, thus increasing the ORR activity. The Pt-specific activity for Pt{sub ML}PdIr/C is three times and 25% higher than that of Pt/C and Pt{sub ML}Pd/C respectively; the Pt-mass activity of Pt{sub ML}PdIr/C is more than 20 times and 25% higher than that of Pt/C and Pt{sub ML}Pd/C, respectively.

  5. Chiral allenes: theoretical VCD and IR spectra

    Microsoft Academic Search

    Joanna E Rode; Jan Cz Dobrowolski

    2003-01-01

    The theoretical geometries, rotational constants, VCD, and IR spectra for the chiral (S)-HXC?C?CFH (X=F, Cl, Br) allene molecules were calculated at the B3PW91\\/aug-cc-pVTZ level. We have shown that there is plausible adequacy between IR spectrum of (S)-1,3-difluoroallene molecule calculated at B3PW91\\/aug-cc-pVTZ level and experimental spectra of the racemate system. For the other molecules studied, the experimental spectra were not published,

  6. Synthesis, crystal structure, computational study of 1-(6-chloro-pyridin-2-yl)-5-hydroxy-1H-pyrazole-3-carboxylic acid methyl ester and its 5-acetoxy analogs

    NASA Astrophysics Data System (ADS)

    Shen, Li-Qun; Huang, Su-Yu; Diao, Kai-Sheng; Lei, Fu-Hou

    2012-08-01

    Two new pyrazole derivatives of 1-(6-chloro-pyridin-2-yl)-5-hydroxy-1H-pyrazole-3-carboxylic acid methyl ester 1a and 5-acetoxy-1-(6-chloro-pyridin-2-yl)-1H-pyrazole-3-carboxylic acid methyl ester 2 were synthesized and characterized by 1H, 13C NMR, IR spectroscopies and HRMS analyses. The molecular structure of 1a and 2 were studied by X-ray diffraction and compared to density-functional-theory (DFT) calculations. The gauge-including atomic orbital (GIAO) method for calculating 1H and 13C NMR nuclear magnetic shielding tensors at the DFT method with 6-31+G* basis set were applied to the compounds 1a and 2. Additionally, thermodynamic properties of the cyclization of the compound 3 to these compounds (1a, 1b, 1c, 4) were investigated by theoretical calculations. These theoretical calculations was shown that the compound 1a was readily formed and was the most stable one. Tautomeric forms of the compound 1a were optimized at the same methods and basis set. The calculated relative Gibbs free energies of the tautomeric forms of 1a were used to estimate the equilibrium constants. It was shown that the 1a was the most stable than tautomer of 1b and 1c in the gas phase.

  7. Infrared, Raman and NMR spectra, conformational stability, normal coordinate analysis and B3LYP calculations of 5-Amino-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde

    NASA Astrophysics Data System (ADS)

    Bahgat, Khaled; EL-Emary, Talaat

    2013-02-01

    FT Raman and IR spectra of the crystallized biologically active molecule, 5-Amino-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde (5-APHC, C11H11N3O) have been recorded and analyzed. The equilibrium geometry, bonding features and harmonic vibrational frequencies of 5-APHC have been investigated with the help of B3LYP density functional theory (DFT) method with 6-31G(d) and 6-311+G(d,p) as basis set. The calculated molecular geometry has been compared with the experimental data. The assignments of the vibrational spectra have been carried out with the help of normal coordinate analysis (NCA) following the scaled quantum mechanical force field (SQM) technique. The optimized geometry shows the co-planarity of the aldehyde group with pyrazole ring. Potential energy surface (PES) scan studies has also been carried out by ab initio calculations with B3LYP/6-311+G(d,p) basis set. The red shifting of NH2 stretching wavenumber indicates the formation of N-H⋯O hydrogen bonding. 1H and 13C NMR spectra were recorded and 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were calculated using the gauge independent atomic orbital (GIAO) method. UV-Vis spectrum of the compound was recorded in the region 200-400 nm and the electronic properties HOMO and LUMO energies were calculated by time-dependent TD-DFT approach. Mulliken charges of the 5-APHC molecule was also calculated and interpreted.

  8. Quantitative 1H nuclear magnetic resonance metabolite profiling as a functional genomics platform to investigate alkaloid biosynthesis in opium poppy.

    PubMed

    Hagel, Jillian M; Weljie, Aalim M; Vogel, Hans J; Facchini, Peter J

    2008-08-01

    Opium poppy (Papaver somniferum) produces a diverse array of bioactive benzylisoquinoline alkaloids and has emerged as a versatile model system to study plant alkaloid metabolism. The plant is widely cultivated as the only commercial source of the narcotic analgesics morphine and codeine. Variations in plant secondary metabolism as a result of genetic diversity are often associated with perturbations in other metabolic pathways. As part of a functional genomics platform, we used (1)H nuclear magnetic resonance (NMR) metabolite profiling for the analysis of primary and secondary metabolism in opium poppy. Aqueous and chloroform extracts of six different opium poppy cultivars were subjected to chemometric analysis. Principle component analysis of the (1)H NMR spectra for latex extracts clearly distinguished two varieties, including a low-alkaloid variety and a high-thebaine, low-morphine cultivar. Distinction was also made between pharmaceutical-grade opium poppy cultivars and a condiment variety. Such phenotypic differences were not observed in root extracts. Loading plots confirmed that morphinan alkaloids contributed predominantly to the variance in latex extracts. Quantification of 34 root and 21 latex metabolites, performed using Chenomx NMR Suite version 4.6, showed major differences in the accumulation of specific alkaloids in the latex of the low-alkaloid and high-thebaine, low-morphine varieties. Relatively few differences were found in the levels of other metabolites, indicating that the variation was specific for alkaloid metabolism. Exceptions in the low-alkaloid cultivar included an increased accumulation of the alkaloid precursor tyramine and reduced levels of sucrose, some amino acids, and malate. Real-time polymerase chain reaction analysis of 42 genes involved in primary and secondary metabolism showed differential gene expression mainly associated with alkaloid biosynthesis. Reduced alkaloid levels in the condiment variety were associated with the reduced abundance of transcripts encoding several alkaloid biosynthetic enzymes. PMID:18550684

  9. Model for simulation of IR countermeasure effect on IR-seeker/missile

    NASA Astrophysics Data System (ADS)

    Berggren, Jan; Kihlen, Ralf G.

    2004-12-01

    TACSI (TACtical SImulation) is an existing simulator used as a tactical environment for manned simulators at Saab Aerosystems. TACSI can also be used as a stand-alone desktop development and simulation tool. TACSI simulates a large number of entities and functions such as platforms, sensors, weapons, signatures, communication, multisensor fusion, decision support etc. TACSI has a rule based pilot model and uses High Level Architecture (HLA) for interfacing with other simulation models. This model, a development of TACSI, simulates the flight dynamics, IR-signature and IR-seeker operation. The dynamic behaviour of the aircraft, the IRCM, the missile and the IR-seeker are modelled. The IR-contrast seen by the seeker through the atmosphere in front of the aircraft and the IRCM are spectrally and dynamically modelled. The seeker operation behaviour and function are also modelled. To implement this in a real-time simulation system simplifications are necessary. This paper describes the simplifications to model the IR-contrast and the seeker function. This model is used to analyse the effect of IR countermeasures (IRCM) on a missile IR-seeker.

  10. Specific control of BMP signaling and mesenchymal differentiation by cytoplasmic phosphatase PPM1H

    PubMed Central

    Shen, Tao; Sun, Chuang; Zhang, Zhengmao; Xu, Ningyi; Duan, Xueyan; Feng, Xin-Hua; Lin, Xia

    2014-01-01

    Bone morphogenetic proteins (BMPs) belong to the TGF-? superfamily of structurally related signaling proteins that regulate a wide array of cellular functions. The key step in BMP signal transduction is the BMP receptor-mediated phosphorylation of transcription factors Smad1, 5, and 8 (collectively Smad1/5/8), which leads to the subsequent activation of BMP-induced gene transcription in the nucleus. In this study, we describe the identification and characterization of PPM1H as a novel cytoplasm-localized Smad1/5/8-specific phosphatase. PPM1H directly interacts with Smad1/5/8 through its Smad-binding domain, and dephosphorylates phospho-Smad1/5/8 (P-Smad1/5/8) in the cytoplasm. Ectopic expression of PPM1H attenuates BMP signaling, whereas loss of PPM1H activity or expression greatly enhances BMP-dependent gene regulation and mesenchymal differentiation. In conclusion, this study suggests that PPM1H acts as a gatekeeper to prevent excessive BMP signaling through dephosphorylation and subsequent nuclear exclusion of P-Smad1/5/8 proteins. PMID:24732009

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

    PubMed

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

    2013-01-01

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

  12. 1H relaxation dispersion in solutions of nitroxide radicals: influence of electron spin relaxation.

    PubMed

    Kruk, D; Korpa?a, A; Kubica, A; Kowalewski, J; Rössler, E A; Moscicki, J

    2013-03-28

    The work presents a theory of nuclear ((1)H) spin-lattice relaxation dispersion for solutions of (15)N and (14)N radicals, including electron spin relaxation effects. The theory is a generalization of the approach presented by Kruk et al. [J. Chem. Phys. 137, 044512 (2012)]. The electron spin relaxation is attributed to the anisotropic part of the electron spin-nitrogen spin hyperfine interaction modulated by rotational dynamics of the paramagnetic molecule, and described by means of Redfield relaxation theory. The (1)H relaxation is caused by electron spin-proton spin dipole-dipole interactions which are modulated by relative translational motion of the solvent and solute molecules. The spectral density characterizing the translational dynamics is described by the force-free-hard-sphere model. The electronic relaxation influences the (1)H relaxation by contributing to the fluctuations of the inter-molecular dipolar interactions. The developed theory is tested against (1)H spin-lattice relaxation dispersion data for glycerol solutions of 4-oxo-TEMPO-d16-(15)N and 4-oxo-TEMPO-d16-(14)N covering the frequency range of 10 kHz-20 MHz. The studies are carried out as a function of temperature starting at 328 K and going down to 290 K. The theory gives a consistent overall interpretation of the experimental data for both (14)N and (15)N systems and explains the features of (1)H relaxation dispersion resulting from the electron spin relaxation. PMID:23556735

  13. 1H relaxation dispersion in solutions of nitroxide radicals: Influence of electron spin relaxation

    NASA Astrophysics Data System (ADS)

    Kruk, D.; Korpa?a, A.; Kubica, A.; Kowalewski, J.; Rössler, E. A.; Moscicki, J.

    2013-03-01

    The work presents a theory of nuclear (1H) spin-lattice relaxation dispersion for solutions of 15N and 14N radicals, including electron spin relaxation effects. The theory is a generalization of the approach presented by Kruk et al. [J. Chem. Phys. 137, 044512 (2012)], 10.1063/1.4736854. The electron spin relaxation is attributed to the anisotropic part of the electron spin-nitrogen spin hyperfine interaction modulated by rotational dynamics of the paramagnetic molecule, and described by means of Redfield relaxation theory. The 1H relaxation is caused by electron spin-proton spin dipole-dipole interactions which are modulated by relative translational motion of the solvent and solute molecules. The spectral density characterizing the translational dynamics is described by the force-free-hard-sphere model. The electronic relaxation influences the 1H relaxation by contributing to the fluctuations of the inter-molecular dipolar interactions. The developed theory is tested against 1H spin-lattice relaxation dispersion data for glycerol solutions of 4-oxo-TEMPO-d16-15N and 4-oxo-TEMPO-d16-14N covering the frequency range of 10 kHz-20 MHz. The studies are carried out as a function of temperature starting at 328 K and going down to 290 K. The theory gives a consistent overall interpretation of the experimental data for both 14N and 15N systems and explains the features of 1H relaxation dispersion resulting from the electron spin relaxation.

  14. Hematocrit and Oxygenation Dependence of Blood 1H2O T1 At 7 Tesla

    PubMed Central

    Grgac, Ksenija; van Zijl, Peter C.M.; Qin, Qin

    2012-01-01

    Knowledge of blood 1H2O T1 is critical for perfusion-based quantification experiments such as arterial spin labeling (ASL) and CBV-weighted MRI using vascular space occupancy (VASO). The dependence of blood 1H2O T1 on hematocrit fraction (Hct) and oxygen saturation fraction (Y) was determined at 7 Tesla using in vitro bovine blood in a circulating system under physiological conditions. Blood 1H2O R1 values for different conditions could be readily fitted using a two-compartment (erythrocyte and plasma) model which are described by a monoexponential longitudinal relaxation rate constant dependence. It was found that T1 = 2171±39 ms for Y = 1 (arterial blood) and 2010±41 ms for Y = 0.6 (venous blood), for a typical Hct of 0.42. The blood 1H2O T1 values in the normal physiological range (Hct from 0.35 to 0.45, and Y from 0.6 to 1.0) were determined to range from 1900 ms to 2300 ms. The influence of oxygen partial pressure (pO2) and the effect of plasma osmolality for different anticoagulants were also investigated. It is discussed why blood 1H2O T1 values measured in vivo for human blood may be about 10-20% larger than found in vitro for bovine blood at the same field strength. PMID:23169066

  15. Possible role of single-voxel (1)H-MRS in differential diagnosis of suprasellar tumors.

    PubMed

    Chernov, Mikhail F; Kawamata, Takakazu; Amano, Kosaku; Ono, Yuko; Suzuki, Takashi; Nakamura, Ryoichi; Muragaki, Yoshihiro; Iseki, Hiroshi; Kubo, Osami; Hori, Tomokatsu; Takakura, Kintomo

    2009-01-01

    The objective of the present study was investigation of the possible role of proton magnetic resonance spectroscopy ((1)H-MRS) for differential diagnosis of suprasellar tumors. Forty patients (23 men and 17 women; median age, 45 years) with suprasellar, hypothalamic, and third ventricle neoplasms underwent long-echo (TR: 2000 ms, TE: 136 ms, 128-256 acquisitions) single-voxel (1)H-MRS before surgical treatment. The volume of the voxel was either 3.4 cc or 8 cc. Spectroscopic data were analyzed by calculation of the various metabolite ratios as well as by determination of the type of the pathological (1)H-MR spectra. There were 19 pituitary adenomas, 7 gliomas, 5 craniopharyngiomas, 3 chordomas, meningioma, hemangiopericytoma, malignant lymphoma, germinoma, Rathke cleft cyst, and hypothalamic hamartoma (one of each). Six tumors were recurrent after initial surgical resection with or without irradiation. Comparison of the individual metabolite ratios revealed only few subtle differences among neoplasms. In the same time, pattern analysis with determination of the type of the pathological (1)H-MR spectra disclosed certain specific characteristics, which seemingly can be used for tumor typing. Meanwhile, metabolic imaging was less effective for characterization of recurrent neoplasms. In conclusion, in cases of initially diagnosed suprasellar tumors with involvement of the hypothalamus and extension into the third ventricle pattern analysis of the single-voxel (1)H-MRS can provide valuable information, which, in addition to structural MRI, can be effectively used for diagnostic purposes. PMID:18825316

  16. Hematocrit and oxygenation dependence of blood (1)H(2)O T(1) at 7 Tesla.

    PubMed

    Grgac, Ksenija; van Zijl, Peter C M; Qin, Qin

    2013-10-01

    Knowledge of blood (1)H2O T1 is critical for perfusion-based quantification experiments such as arterial spin labeling and cerebral blood volume-weighted MRI using vascular space occupancy. The dependence of blood (1)H2O T1 on hematocrit fraction (Hct) and oxygen saturation fraction (Y) was determined at 7 T using in vitro bovine blood in a circulating system under physiological conditions. Blood (1)H2O R1 values for different conditions could be readily fitted using a two-compartment (erythrocyte and plasma) model, which are described by a monoexponential longitudinal relaxation rate constant dependence. It was found that T1 = 2171 ± 39 ms for Y = 1 (arterial blood) and 2010 ± 41 ms for Y = 0.6 (venous blood), for a typical Hct of 0.42. The blood (1)H2O T1 values in the normal physiological range (Hct from 0.35 to 0.45, and Y from 0.6 to 1.0) were determined to range from 1900 to 2300 ms. The influence of oxygen partial pressure (pO2) and the effect of plasma osmolality for different anticoagulants were also investigated. It is discussed why blood (1)H2O T1 values measured in vivo for human blood may be about 10-20% larger than found in vitro for bovine blood at the same field strength. PMID:23169066

  17. Kinetic Isotope Effects for the Reactions of Muonic Helium and Muonium with H2

    SciTech Connect

    Fleming, Donald G.; Arseneau, Donald J.; Sukhorukov, Oleksandr; Brewer, Jess H.; Mielke, Steven L.; Schatz, George C.; Garrett, Bruce C.; Peterson, Kirk A.; Truhlar, Donald G.

    2011-01-28

    The neutral muonic helium atom may be regarded as the heaviest isotope of the hydrogen atom, with a mass of ~4.1 amu (4.1H), because the negative muon screens one proton charge. We report the reaction rate of 4.1H with 1H2 to produce 4.1H1H + 1H at 295 to 500 K. The experimental rate constants are compared with the predictions of accurate quantum mechanical dynamics calculations carried out on an accurate Born-Huang potential energy surface and with previously measured rate constants of 0.11H (where 0.11H is shorthand for muonium). Kinetic isotope effects can be compared for the unprecedentedly large mass ratio of 36. The agreement with accurate quantum dynamics is quantitative at 500 K, and variational transition state theory is used to interpret the extremely low (large inverse) kinetic isotope effects in the 10-4 to 10-2 range.

  18. Two 18? Ti(IV) eta5-Cp-tris(sec-amido)-type complexes derived from 1H-imidazol-2-yl side-chain functionalized cyclopentadienes.

    PubMed

    Wang, Xiaowu; Nie, Wanli; Ge, Fang; Borzov, Maxim V

    2009-07-01

    Achiral {2-[2-(eta(5)-cyclopentadienyl)-2-methylpropyl]-1H-imidazolyl-kappaN(1)}bis(N,N-diethylamido-kappaN)titanium(IV), [Ti(C(4)H(10)N)(2)(C(12)H(14)N(2))], (I), and closely related racemic (SR)-{2-[(eta(5)-cyclopentadienyl)(phenyl)methyl]-1H-imidazolyl-kappaN(1)}bis(N,N-diethylamido-kappaN)titanium(IV), [Ti(C(4)H(10)N)(2)(C(15)H(12)N(2))], (II), have been prepared by direct reactions of Ti(NEt(2))(4) and the corresponding 1H-imidazol-2-yl side-chain functionalized cyclopentadienes. In compound (II), there are two crystallographically independent molecules of very similar geometries connected by a noncrystallographic pseudosymmetry operation akin to a 2(1) screw axis. All Ti-ligating N atoms in both (I) and (II) are in planar environments, which is indicative of an additional N-->Ti ppi-dpi donation. This fact and the 18? nature of both (I) and (II) are additionally supported by quantum chemical single-point density functional theory (DFT) computations. PMID:19578257

  19. IR temperature measurements in microwave heating

    Microsoft Academic Search

    G. Cuccurullo; P. G. Berardi; R. Carfagna; V. Pierro

    2002-01-01

    In this paper a technique for the evaluation of the dielectric constant of a sample placed inside a microwave oven and confined in a cylindrical box is proposed. The box acts as a waveguide so that a simple model for the propagating wave can be assumed. Since traditional techniques for temperature measurements cannot be applied in microwave heating, the IR

  20. Temporal method for IR minefield feature detection

    NASA Astrophysics Data System (ADS)

    Sjokvist, Stefan; Linderhed, Anna; Nyberg, Sten; Uppsall, Magnus S.

    2004-09-01

    The overall objective of this work is to investigate the possibilities of using airborne IR sensors for the purpose of detecting minefield features, such as land mines. A method is proposed for temporal analysis by extracting relevant information from diurnal IR images utilizing a combination of thermodynamic modelling, signal and image processing. This paper presents results from a field test of level 2 survey in May 2003 of suspected mine-polluted areas in Croatia. Airborne data was acquired using an IR sensor mounted on a rotary wing UAV. A weather station was used to collect weather data, and pt-100 temperature sensors recorded the temperature gradient in the soil and in reference markers that were used for calibrating the IR camera. The proposed method compares simulated temporal temperature with image data collected at several times during a diurnal cycle from the same area, pixel by pixel. The images are co-registered and calibrated with respect to reference values. The numerical model is based on physical laws and is set with relevant properties, geometries, materials, surface coefficients and the influence of the actual weather sets the boundary conditions. This paper shows some results from using temporal features for detection of different relevant objects in a real minefield.

  1. IR-4 Ornamental Horticulture Program Trial Report

    E-print Network

    Lieth, J. Heinrich

    (s): 25887 (Cyclanilide), 25888 (Fascination), 25891 (MaxCel) and 25893 (ProVide) 1 Project Title: Efficacy and Phytotoxicity of Cyclanilide, Fascination, MaxCel and Provide for Increased Branching of Hydrangea (Hydrangea macrophylla `Angel Robe') IR4 PR#: 25887 (Cyclanilide), 25888 (Fascination), 25891 (MaxCel) and 25893 (Pro

  2. Microbiological characterizations by FT-IR spectroscopy

    Microsoft Academic Search

    Dieter Naumann; Dieter Helm; Harald Labischinski

    1991-01-01

    Infrared signals of microorganisms are highly specific fingerprint-like patterns that can be used for probing the identity of microorganisms. The simplicity and versatility of Fourier-transform infrared spectroscopy (FT-IR) makes it a versatile technique for rapid differentiation, classification, identification and large-scale screening at the subspecies level.

  3. Adaptive IR for exploratory search support

    Microsoft Academic Search

    Daniel T. J. Backhausen

    2012-01-01

    Most Information Retrieval (IR) software is designed to fit a general user where users are submitting queries and the retrieval system returns a ranked list of results. Regardless of the user, the query always returns the same list of results. Individual aspects like age, gender, profession or experience are often not taken into account, for example the difference in searching

  4. Sensitive IR narrow band optimized microspectrometer

    Microsoft Academic Search

    David L Wetzel

    2002-01-01

    Customization of a standard model confocally masked FT-IR microspectrometer to maximize the signal for a particular narrow band of the spectrum and minimize noise is described. In this case the motivation was to detect minor concentrations of deuterated species in a matrix of tissue. However, the instrumental modifications used for this particular task are applicable to narrow band sensitization in

  5. IR circuit board and IC failure detection

    Microsoft Academic Search

    Ernest Keenan; R. Glenn Wright; Marek Zgol; Robert Mulligan; Victor Tagliavia; Larry V. Kirkland

    2004-01-01

    This paper describes research and development efforts in the use of infrared (IR) laser beams for detecting failures in integrated circuits resident on printed circuit boards. This work involves taking advantage of the transparency of the silicon substrate of ICs to radiation in the near infrared (NIR) spectrum to devise a non-invasive method for imaging the component circuitry of the

  6. Integrated circuit failure detection using IR laser

    Microsoft Academic Search

    Ernest Keenan; Larry V. Kirkland; R. G. Wright; M. Zgol; D. Adebimpe

    2002-01-01

    This paper presents unique research efforts related to the use of infrared (IR) laser beams for detecting failures in integrated circuits. The transparency of the silicon substrate of ICs to radiation in the near infrared (NIR) spectrum permits a noninvasive method for imaging the component circuitry of the IC. A laser test fixture consisting of a 1064 nm continuous wave

  7. Crack growth induced by sonic IR inspection

    Microsoft Academic Search

    John C. Chen; Jacob Kephart; Kyle Lick; William T. Riddell

    2007-01-01

    We have developed an experiment to study the propagation of laboratory-synthesized fatigue cracks under various controlled conditions during Sonic IR inspection. The experiment provides for good repeatability in testing. The parameters of interest include the initial crack length, load history (stress intensity and load ratio) during crack generation, geometry of the crack, material and also the various conditions involving the

  8. atomic response IR = |ER(nr) + Eat |

    E-print Network

    Paris-Sud XI, Université de

    ER(nr) non- resonant reflection (resonant) atomic response windo w dilute vapou r IR = |ER 6 8 9 @ A B 8 8 9 @ A B 8 (qualitative approach) Irefl = |ER(nr)1 + ER(nr)2 + Eat|² windo w dilute n1 =1 n3 = n1 windo w Continuity equations at the two boundaries between the three media: - air, n1

  9. Espectroscopía Espacial en el IR-Lejano

    Microsoft Academic Search

    Javier R. Goicoechea; J. Cernicharo

    2003-01-01

    Debido a la opacidad atmosférica, el dominio IR--lejano del espectro electromagnético ha sido la última ventana en ser utilizada por la Astrofísica Molecular. El potencial que supone abrir este nuevo rango de frecuencias a través de la espectroscopía molecular ha comenzado a ser explotado con el Infrared Space Observatory (ISO). La sensibilidad de la instrumentación embarcada en dicho satélite no

  10. Laser reflexotherapy in UV and IR wavelengths

    NASA Astrophysics Data System (ADS)

    Mokretsov, V. V.; Utz, Sergei R.; Vinichenko, N. V.; Barabanov, Alexander Y.; Tuchin, Valery V.

    1993-06-01

    The purpose of this work was the investigation of the effects of UV and IR laser irradiation on the central and regional hemodynamics of agricultural mechanization workers with border limited arterial hypertension, whose arterial pressure was within the limits from 140 to 90 mm of mercury column up to 159 and 94 mm mercury column.

  11. Irreversible laser damage in ir detector materials.

    PubMed

    Bartoli, F; Esterowitz, L; Kruer, M; Allen, R

    1977-11-01

    Irreversible laser damage phenomena are investigated in pyroelectric and semiconductor ir detector materials. Thermal damage phenomena in these materials are reviewed, and new results are presented. Theoretical models, which successfully describe thermal damage in detector materials, are reviewed, and criteria for the application of these models are discussed. PMID:20174269

  12. The Ultra-Luminous IR Galaxy Population

    E-print Network

    K. D. Borne; H. Bushouse; L. Colina; R. A. Lucas; S. Arribas

    2000-09-04

    We summarize results from an on-going Hubble Space Telescope (HST) survey of a large sample of ULIRGs (Ultra-Luminous IR Galaxies). New ground-based multi-fiber spectroscopic observations are now being obtained to complement the HST data and to assist in the interpretation of these complex objects.

  13. Revisiting IR Techniques for Collaborative Search Strategies

    Microsoft Academic Search

    Hideo Joho; David Hannah; Joemon M. Jose

    2009-01-01

    This paper revisits some of the established Information Re- trieval (IR) techniques to investigate eective collaborative search strate- gies. We devised eight search strategies that divided labour and shared knowledge in teams using relevance feedback and clustering. We evalu- ated the performance of strategies with a user simulation enhanced by a query-pooling method. Our results show that relevance feedback is

  14. Introduction Mid-Infrared (IR) spectroscopy

    E-print Network

    Wells, Mathew G. - Department of Physical and Environmental Sciences, University of Toronto

    in order to obtain a good quality spectrum. Traditionally IR spectrometers have been used to analyze solids variation Higher quality spectral databases for more precise material verification and identification Key in a liquid to form a mull. The most commonly used liquid is mineral oil (nujol). Typically no more than 20 mg

  15. IR sensors and imagers in networked operations

    NASA Astrophysics Data System (ADS)

    Breiter, Rainer; Cabanski, Wolfgang

    2005-05-01

    "Network-centric Warfare" is a common slogan describing an overall concept of networked operation of sensors, information and weapons to gain command and control superiority. Referring to IR sensors, integration and fusion of different channels like day/night or SAR images or the ability to spread image data among various users are typical requirements. Looking for concrete implementations the German Army future infantryman IdZ is an example where a group of ten soldiers build a unit with every soldier equipped with a personal digital assistant (PDA) for information display, day photo camera and a high performance thermal imager for every unit. The challenge to allow networked operation among such a unit is bringing information together and distribution over a capable network. So also AIM's thermal reconnaissance and targeting sight HuntIR which was selected for the IdZ program provides this capabilities by an optional wireless interface. Besides the global approach of Network-centric Warfare network technology can also be an interesting solution for digital image data distribution and signal processing behind the FPA replacing analog video networks or specific point to point interfaces. The resulting architecture can provide capabilities of data fusion from e.g. IR dual-band or IR multicolor sensors. AIM has participated in a German/UK collaboration program to produce a demonstrator for day/IR video distribution via Gigabit Ethernet for vehicle applications. In this study Ethernet technology was chosen for network implementation and a set of electronics was developed for capturing video data of IR and day imagers and Gigabit Ethernet video distribution. The demonstrator setup follows the requirements of current and future vehicles having a set of day and night imager cameras and a crew station with several members. Replacing the analog video path by a digital video network also makes it easy to implement embedded training by simply feeding the network with simulation data. The paper addresses the special capabilities, requirements and design considerations of IR sensors and imagers in applications like thermal weapon sights and UAVs for networked operating infantry forces.

  16. Metabolomic differentiation of Cannabis sativa cultivars using 1H NMR spectroscopy and principal component analysis.

    PubMed

    Choi, Young Hae; Kim, Hye Kyong; Hazekamp, Arno; Erkelens, Cornelis; Lefeber, Alfons W M; Verpoorte, Robert

    2004-06-01

    The metabolomic analysis of 12 Cannabis sativa cultivars was carried out by 1H NMR spectroscopy and multivariate analysis techniques. Principal component analysis (PCA) of the 1H NMR spectra showed a clear discrimination between those samples by principal component 1 (PC1) and principal component 3 (PC3) in cannabinoid fraction. The loading plot of PC value obtained from all 1)H NMR signals shows that Delta9-tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA) are important metabolites to differentiate the cultivars from each other. The discrimination of the cultivars could also be obtained from a water extract containing carbohydrates and amino acids. The level of sucrose, glucose, asparagine, and glutamic acid are found to be major discriminating metabolites of these cultivars. This method allows an efficient differentiation between cannabis cultivars without any prepurification steps. PMID:15217272

  17. Effect of fertilizers on galanthamine and metabolite profiles in Narcissus bulbs by 1H NMR.

    PubMed

    Lubbe, Andrea; Choi, Young Hae; Vreeburg, Peter; Verpoorte, Robert

    2011-04-13

    Narcissus bulbs contain the biologically active alkaloid galanthamine, and Narcissus is being developed as a natural source of the molecule for the pharmaceutical industry. The effect of fertilizer on galanthamine production was investigated in a field study using a (1)H nuclear magnetic resonance (NMR) metabolite profiling approach. Galanthamine was quantitated and major metabolites in the bulbs were identified. The application of standard fertilization levels of nitrogen and potassium caused a significant increase in galanthamine as compared to a control. Multivariate data analysis of the (1)H NMR data revealed that applying double the standard level of nitrogen fertilizer resulted in production of more amino acids and citric acid cycle intermediates, but not more galanthamine. The results indicated that standard levels of fertilizer currently applied in The Netherlands are sufficient for optimal galanthamine accumulation in the bulbs. This study shows how (1)H NMR-based metabolic profiling can provide insight into the response of plant metabolism to agricultural practices. PMID:21375239

  18. Preclinical 1H-MRS neurochemical profiling in neurological and psychiatric disorders

    PubMed Central

    Lee, Moonnoh R; Denic, Aleksandar; Hinton, David J; Mishra, Prasanna K; Choi, Doo-Sup; Pirko, Istvan; Rodriguez, Moses; Macura, Slobodan I

    2014-01-01

    The ongoing development of animal models of neurological and psychiatric disorders in combination with the development of advanced nuclear magnetic resonance (NMR) techniques and instrumentation has led to increased use of in vivo proton NMR spectroscopy (1H-MRS) for neurochemical analyses. 1H-MRS is one of only a few analytical methods that can assay in vivo and longitudinal neurochemical changes associated with neurological and psychiatric diseases, with the added advantage of being a technique that can be utilized in both preclinical and clinical studies. In this review, recent progress in the use of 1H-MRS to investigate animal models of neurological and psychiatric disorders is summarized with examples from the literature and our own work. PMID:22877223

  19. Knoevenagel Reaction of Unprotected Sugars

    NASA Astrophysics Data System (ADS)

    Scherrmann, Marie-Christine

    The Knoevenagel reaction of unprotected sugars was investigated in the 1950s using zinc chloride as promoter. The so-called Garcia Gonzalez reaction had been almost forgotten for 50 years, until the emergence of new water tolerant catalysts having Lewis acid behavior. The reaction was thus reinvestigated and optimal conditions have been found to prepare trihydroxylated furan derivatives from pentose or ?-tetrahydrofuranylfuran from hexoses with non-cyclic ?-keto ester or ?-diketones. Other valuable compounds such as ?-linked tetrahydrobenzofuranyl glycosides or hydroxyalkyl-3,3,6,6,-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione can be obtained using cyclic ?-dicarbonylic derivatives. Apart from one report in the 1950s, the Knoevenagel reaction of unprotected carbohydrate in basic condition has been studied only in the mid-1980s to prepare C-glycosyl barbiturates from barbituric acids and, later on, from non-cyclic ?-diketones, ?-C-glycosidic ketones. The efficient method exploited to prepare such compounds has found an industrial development in cosmetics.

  20. Novel palladium(II) and platinum(II) complexes of biocidal benzisothiazolinone (Bit); X-ray crystal structures of co-crystallised Bit\\/BitO and cis-Pd(en)(Bit ?1H) 2·H 2O

    Microsoft Academic Search

    Darren M. Griffith; Aisleen Haughey; Sunisha Chahal; Helge Müller-Bunz; Celine J. Marmion

    2010-01-01

    Reaction of benzisothiazolinone (Bit), a well-known biocide, with the Pd(II) and Pt(II) am(m)ine precursors cis-[Pd(en)(H2O)2](NO3)2 and cis-[Pt(NH3)2(H2O)2](NO3)2 yielded cis-Pd(en)(Bit?1H)2 and cis-Pt(NH3)2(Bit?1H)2, respectively. Bit is bound to the metal centres in both cases through the deprotonated isothiazolinone N. The crystal structures of a Bit\\/BitO co-crystal and cis-Pd(en)(Bit?1H)2·H2O are also described.

  1. Characterization of wet aggregate stability of soils by (1) H-NMR relaxometry.

    PubMed

    Buchmann, C; Meyer, M; Schaumann, G E

    2014-10-10

    For the assessment of soil structural stability against hydraulic stress, wet sieving or constant head permeability tests are typically used but rather limited in their intrinsic information value. The multiple applications of several tests is the only possibility to assess important processes and mechanisms during soil aggregate breakdown, e.g. the influences of soil fragment release or differential swelling on the porous systems of soils or soil aggregate columns. Consequently, the development of new techniques for a faster and more detailed wet aggregate stability assessment is required. (1) H nuclear magnetic resonance relaxometry ((1) H-NMR relaxometry) might provide these requirements because it has already been successfully applied on soils. We evaluated the potential of (1) H-NMR relaxometry for the assessment of wet aggregate stability of soils, with more detailed information on occurring mechanisms at the same time. Therefore, we conducted single wet sieving and constant head permeability tests on untreated and 1% polyacrylic acid-treated soil aggregates of different textures and organic matter contents, subsequently measured by (1) H-NMR relaxometry after percolation. The stability of the soil aggregates were mainly depending on their organic matter contents and the type of aggregate stabilization, whereby additional effects of clay swelling on the measured wet aggregate stability were identified by the transverse relaxation time (T2 ) distributions. Regression analyses showed that only the percentage of water stable aggregates could be determined accurately from percolated soil aggregate columns by (1) H-NMR relaxometry measurements. (1) H-NMR relaxometry seems a promising technique for wet aggregate stability measurements but should be further developed for nonpercolated aggregate columns and real soil samples. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25303035

  2. Accelerator production of 122Xe(20.1 h) as a source of 122I(3.6 m) labeled radiopharmaceuticals for applications in positron emission tomography

    NASA Astrophysics Data System (ADS)

    Lagunas-Solar, M. C.; Zeng, N. X.; Castaneda, C. M.; Carvacho, O. F.; VanBrocklin, H. F.; O'Neil, J. P.; Padgett, H. C.; Budinger, T. F.

    1999-06-01

    Iodine-122 (3.6 m) radiopharmaceuticals have a proven potential for accelerator-free PET studies, including brain and heart perfusion, using a 122Xe?122I transportable generator. Nuclear reactions with up to 70 MeV proton beams were studied to produce the parent 122Xe(20.1 h) radionuclide. Theoretical and experimental measurements indicated that 122Xe can be produced in high yields allowing for an extensive use of a 122Xe?122I generator capable of producing multiple doses of 122I radiopharmaceuticals. Other lower energy reactions were studied and the results indicated the possibility of developing new methods that could be available to a larger number of commercial and research accelerators operating worldwide.

  3. Crystal structure of 3-methyl-5-tri­methyl­silyl-1H-pyrazole

    PubMed Central

    Ferrence, Gregory M.; Kocher, Joshua L.

    2015-01-01

    The title compound, C7H14N2Si, crystallizes in a tetra­gonal space group and exists as an N—H?N hydrogen-bonded tetra­mer, formed around the crystallographic fourfold rotoinversion axis. The mol­ecular identity is clearly the 5-tri­methyl­silyl-3-methyl-1H-pyrazole tautomer and the structure is isomorphous with that of 5-tert-butyl-3-methyl-1H-pyrazole [Foces-Foces & Trofimenko (2001 ?). Acta Cryst. E57, o32–o34].

  4. 1 H MAS NMR spectra of hydroxyl species on diatomite surface

    Microsoft Academic Search

    Yuan Peng; Wu Daqing; Chen Zhong; Chen Zhiwei; Lin Zhongyu; Diao Guiyi; Peng Jinlian

    2001-01-01

    High spinning speed1H magic-angle spinning nuclear magnetic resonance (1H MAS NMR) was used to detect surface hydroxyl groups of diatomite, which include isolated hydroxyl groups and hydrogen-bonded\\u000a hydroxyl groups, and water adsorbed on diatomite surface that include pore water and hydrogen-bonded water. The corresponding\\u000a proton chemical shifts of above species are ca. 2.0, 6.0–7.1, 4.9 and 3.0 respectively. Accompanied by

  5. 1H NMR study of inclusion compounds of phenylurea derivatives in ?-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Dupuy, N.; Barbry, D.; Bria, M.; Marquis, S.; Vrielynck, L.; Kister, J.

    2005-04-01

    Proton nuclear magnetic resonance spectroscopy ( 1H NMR), which has become an important tool for the study "in situ" of ?-cyclodextrin (?-CD) complexes, was used to study and structurally characterize the inclusion complexes formed between ?-CD and isoproturon, fenuron, monuron and diuron. The high variation of the chemical shifts from the proton located inside the cavity (H-3, H-5 and H-6) coupled with the non variation of the one located outer sphere of the ?-CD (H-1, H-2 and H-4) provided clear evidence of the inclusion phenomena. Two-dimensional rotating frame Overhauser effect spectroscopy (ROESY) experiments were carried out to further support the proposed inclusion mode.

  6. Simultaneous localized 1H STEAM/31P ISIS spectroscopy in vivo.

    PubMed

    van Sluis, R; Yongbi, N M; Payne, G S; Leach, M O

    1996-04-01

    A sequence for simultaneous acquisition of 1H STEAM and 31P ISIS spectra is described, and 1H and 31P spectra obtained simultaneously from the same volume of interest in both a phantom and a volunteer are presented. The STEAM and ISIS parts of the sequence use a common gradient scheme that is also used during the localized shimming process, partially compensating for eddy current effects. It is demonstrated that this method of simultaneous multinuclear spectroscopy does not compromise the localization performance of the sequence. PMID:8992195

  7. Inclusion complex of benzocaine and ?-cyclodextrin: 1H NMR and isothermal titration calorimetry studies

    NASA Astrophysics Data System (ADS)

    Mic, Mihaela; P?rn?u, Adrian; Bogdan, Mircea; Turcu, Ioan

    2013-11-01

    The supramolecular structure of the inclusion complex of ?-cyclodextrin with benzocaine in aqueous solution has been investigated by 1H NMR spectroscopy and isothermal titration nanocalorimetry (ITC). Analysis of 1H NMR data by continuous variation method indicates that the benzocaine: ?-cyclodextrin inclusion complex occurs and has a 1:1 stoichiometry. Rotating frame NOE spectroscopy (ROESY) was used to ascertain the solution geometry of the host-guest complex which indicates that the benzocaine molecule was included with the aromatic ring into the cyclodextrin cavity. Although the affinity of benzocaine for cyclodextrin is relatively high, the association constant cannot be measured using ITC due to the low solubility of benzocaine in water.

  8. Solid-state variable-temperature 1H MAS NMR studies on deuterated polyethylene.

    PubMed

    Chen, Q; Hurosu, H; Ando, I; Wu, X

    1997-02-01

    Solid-state variable-temperature/magic angle spinning (VT/MAS) 1H NMR measurements were carried out on deuterated polyethylene. From these experimental results it was found that the 1H chemical shift induced by conformational and morphological changes of the polyethylene sample is within the linewidth of approximately 0.5 ppm. Furthermore, from MAS/dipolar decoupling experiments it was found that the resonance frequency of the proton varies linearly with the inverse square of the deuterium decoupling power. This experimental finding is discussed theoretically. PMID:9176937

  9. Structure and elementary properties of the new Ir hollandite Rb{sub 0.17}IrO{sub 2}

    SciTech Connect

    Schoop, Leslie M., E-mail: lschoop@princeton.edu [Department of Chemistry, Princeton University, Princeton, NJ 08544 (United States); Max-Planck-Institut für Chemische Physik fester Stoffe, 01187 Dresden (Germany); Krizan, Jason W.; Gibson, Quinn D.; Cava, R.J. [Department of Chemistry, Princeton University, Princeton, NJ 08544 (United States)

    2014-01-15

    We report the synthesis and structural characterization of the new Ir holladite, Rb{sub 0.17}IrO{sub 2}. Rb{sub 0.17}IrO{sub 2} crystallizes in the tetragonal hollandite structure. In contrast to the previously reported monoclinic Ir hollandite K{sub 0.25}IrO{sub 2}, we do not observe a difference in Ir–O bond lengths in Rb{sub 0.17}IrO{sub 2} and thus find Ir in an average oxidation state of + 3.83. We also report and compare the electronic and magnetic properties of Rb{sub 0.17}IrO{sub 2} and K{sub 0.25}IrO{sub 2}, finding that they are both metallic and Pauli paramagnets further supporting that the electrons are delocalized in the Ir 5d states. - Graphical abstract: Crystal structure of Rb{sub 0.17}IrO{sub 2} (right), and the SEM image of Rb{sub 0.17}IrO{sub 2}, showing the growth of thin needles (left). Display Omitted - Highlights: • New iridium hollandite. • Naturally grows in very thin wires. • Elementary physical properties of Ir holladites reported for the first time metallic conductor and paramagnetic.

  10. Power scaling of cw and pulsed IR and mid-IR OPSLs

    NASA Astrophysics Data System (ADS)

    Moloney, J. V.; Hader, J.; Wang, T.-L.; Ying, Yi.; Kaneda, Y.; Yarborough, J. M.; Rotter, T. J.; Balakrishnan, G.; Hains, C.; Koch, S. W.; Stolz, W.; Kunert, B.; Bedford, R.

    2011-03-01

    We present an overview of the quantum design, growth and lasing operation of both IR and mid-IR OPSL structures aimed at extracting multi-Watt powers CW and multi-kW peak power pulsed. Issues related to power scaling are identified and discussed. The IR OPSLs based on InGaAs QW bottom emitters targeted at wavelengths between 1015nm and 1040nm are operated in CW mode (yielding a maximum power of 64W) and pulsed (peak power of 245W). The mid-IR top emitter OPSLs designed to lase at 2?m are based on a novel lattice mismatched growth using InGaSb QWs and yield a maximum peak power of 350W pulsed.

  11. The NASA Ames PAH IR Spectroscopic Database and the far-IR

    NASA Astrophysics Data System (ADS)

    Boersma, C.; Allamandola, L. J.; Bauschlicher, C. W.; Ricca, A.; Cami, J.; Peeters, E.; Sánchez de Armas, F.; Puerta Saborido, G.; Mattioda, A. L.; Hudgins, D. M.

    2011-03-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are widespread across the Universe and influence many stages of the Galactic lifecycle. The presence of PAHs has been well established and the rich mid-IR PAH spectrum is now commonly used as a probe into (inter)stellar environments. The NASA Ames PAH IR Spectroscopic Database has been key to test and refine the "PAH hypothesis". This database is a large coherent set (>600 spectra) of laboratory measured and DFT computed infrared spectra of PAHs from C10H8 to C130H28 and has been made available on the web at ( http://www.astrochem.org/pahdb). With a new spectral window opening up; the far-IR, the study of PAH far-IR spectra and the quest for identifying a unique member of the interstellar PAH family has begun. To guide this research, the far-IR (>20 ?m) spectra of different sets of PAHs are investigated using the NASA Ames PAH IR Spectroscopic Database. These sets explore the influence of size, shape, charge and composition on the far-IR PAH spectrum. The far-IR is also the domain of the so-called "drumhead" modes and other molecular vibrations involving low order bending vibrations of the carbon skeleton as a whole. As with drums, these are molecule and shape specific and promise to be a key diagnostic for specific PAHs. Here, the sensitivity of these "drumhead" modes to size and shape is assessed by comparing the frequencies of the lowest drumhead modes of a family of circular shaped (the coronene "family") and rhombus shaped (the pyrene "family") PAH molecules. From this study, some consequences for an observing strategy are drawn.

  12. Structural and computational features of four highly polar quinolin-2(1H)-ylidene derivatives: Equilibrium preference for enaminothione, enamine, and enaminone tautomeric structures

    NASA Astrophysics Data System (ADS)

    Nesterov, Volodymyr V.; Yang, Li; Nesterov, Vladimir N.; Richmond, Michael G.

    2013-12-01

    The coupling of the active methylene compounds 2-cyanothioacetamide, malononitrile, and ethyl cyanoacetate with quinoline-N-oxide and 6-methoxyquinoline-N-oxide has been investigated, and the compounds (2Z)-2-cyano-2-quinolin-2(1H)-ylidene-ethanethioamide (1a), 6-methoxyquinolin-2(1H)-ylidene-propanedinitrile (1b), ethyl (2Z)-cyano-6-methoxyquinolin-2(1H)-ylidene-ethanoate (1c), and (2Z)-2-cyano-2-(6-methoxyquinolin)-2(1H)-ylidene-ethanethioamide (1d) have been isolated. Compounds 1a-d have been characterized by a combination of IR and NMR spectroscopies, combustion and X-ray diffraction analyses. The solid-state structure of each molecule is found to be almost planar and contains a hydrogen atom attached to the quinoline nitrogen. The observed pattern of exocyclic bond lengths signifies the existence of strong conjugation between quinoline fragment and the electron-withdrawing substituent situated at C-1. The CS bond distance of 1.708(1) and 1.704(1) Å in 1a and 1d, respectively, is intermediate in length between CS and CS bond distances. The CO bond distance in 1c displays a similar elongation [1.237(2) Å] relative to the CO bond distance in non-conjugated organic carbonyl compounds. All four structures exhibit an exocyclic CC bond between the heterocycle and the electron-withdrawing substituent that is elongated to 1.400 Å, a feature consistent with significant CC bond contribution. Strong intramolecular H-bonds in 1a, 1c, and 1d help promote molecular conjugation of the heterocycle and exocyclic appendage defined by the atoms HNCCCS/O into flat six-membered rings. In the crystals of 1a and 1b, the molecules are aligned in head-to-head stacks, while in the crystalline lattice of 1c and 1d the molecules exhibit a motif involving head-to-tail stacks. Intermolecular H-bonds link molecules 1a, 1b, and 1d into centrosymmetric dimers, while in the crystal of 1c weak intermolecular CH⋯N H-bonds orient molecules into zigzag chains. The bonding in 1a-d has been examined by electronic structure calculations, and these data are discussed with respect to the X-ray diffraction structures and the equilibrium preference for the enaminothione (1a and 1d), enamine (1b), and enaminone (1c) tautomers.

  13. STATUS OF FAST IR ORBIT FEEDBACK AT RHIC.

    SciTech Connect

    MONTAG, C.; CUPOLO, J.; GLENN, J.; LITVINENKO, V.; MARUSIC, A.; MENG, W.; MICHNOFF, R.; ROSER, T.; SCHULTHEISS, C.; TUOZZOLO, J.

    2006-06-26

    To compensate modulated beam-beam offsets caused by mechanical vibrations of IR triplet quadrupoles at frequencies around 10 Hz, a fast IR orbit feedback system has been developed. We report design considerations and recent status of the system.

  14. Lithographie laser Calmon Pierre Franois IR2 15 %

    E-print Network

    Ingrand, François

    17 % Pinaud Sébastien AI 24 % Mazas Mathieu1 AI 22 % Electrochimie - Gravure anisotrope du Si Christophe AI 25 % Gravure plasma Dubreuil Pascal IR2 31 % Belharet Djaffar1 IR2 17 % Jets d'encre Conédéra

  15. 1H, 13C and 31P MAS NMR studies of lyophilized brain tumors.

    PubMed

    Marsza?ek, R; Pisklak, M; Horszty?ski, D; Wawer, I

    2010-01-01

    (1)H, (13)C and (31)P magic angle spinning magnetic resonance spectra (MAS NMR) of lyophilized brain tissue specimens were recorded. Among the 35 cases of brain tumors there were 24 glioblastomas, seven meningiomas and a few other types. (1)H NMR measurements were performed with a MAS speed of 33 kHz. The intense CH(3), CH(2) and CH peaks in the (1)H spectrum result from fatty acid residues of phospholipids, which are "mobile enough" besides the anhydrous environment. (13)C CPMAS spectra revealed the resonances of creatine and guanidine carbons; the high intensity signals arise from carbonyl groups and methylene carbons of lipids. In particular we found a fraction of mobile lipids, characterized by narrow resonances and long T(1rho)(H) Overlapped resonances of phospholipids head groups contributed to the peak at 4-7 ppm in the (31)P MAS NMR spectra. Our results indicate that (1)H and (13)C MAS NMR are able to characterize tumor types: differentiate glioblastomas from meningiomas and shed light on tumor biochemical characteristics. However, water soluble metabolites are not observed and macromolecules yield broad overlapped resonances. Generally, lyophilization significantly decreases discriminative potential of NMR analysis. PMID:20133109

  16. Delocalization in random polymer models S. Jitomirskaya 1 , H. SchulzBaldes 2 , G. Stolz 3

    E-print Network

    building blocks modeling two di#erent polymers. The associated polymer transfer matrices are supposedDelocalization in random polymer models S. Jitomirskaya 1 , H. Schulz­Baldes 2 , G. Stolz 3 1 at Birmingham, Al, 35294 USA Abstract A random polymer model is a one­dimensional Jacobi matrix randomly

  17. CALCIUM TRANSLOCATION IN THE AVIAN SHELL GLAND (1) H. SCHRAER Rosemary SCHRAER

    E-print Network

    Boyer, Edmond

    CALCIUM TRANSLOCATION IN THE AVIAN SHELL GLAND (1) H. SCHRAER Rosemary SCHRAER Department because of the large changes in calcium metabolism that occurred during the reproductive cycle on the movement of calcium across the shell gland of the domestic hen and some of the steps which led to this area

  18. Ammonium Trifluoroacetate-Mediated Synthesis of 3,4-dihydropyrimidin-2(1H)-ones

    PubMed Central

    Raju, Chandran; Uma, R.; Madhaiyan, Kalaipriya; Sridhar, Radhakrishnan; Ramakrishna, Seeram

    2011-01-01

    A simple and economic synthesis of 3,4-dihydropyrimidin-2(1H)-ones using ammonium trifluoroacetate as catalyst and as solid support is accomplished. Easy workup procedure for the synthesis of title compounds is well arrived at and is well documented. PMID:24052820

  19. 1H NMR study of inclusion compounds of phenylurea derivatives in ?-cyclodextrin

    Microsoft Academic Search

    N. Dupuy; D. Barbry; M. Bria; S. Marquis; L. Vrielynck; J. Kister

    2005-01-01

    Proton nuclear magnetic resonance spectroscopy (1H NMR), which has become an important tool for the study “in situ” of ?-cyclodextrin (?-CD) complexes, was used to study and structurally characterize the inclusion complexes formed between ?-CD and isoproturon, fenuron, monuron and diuron. The high variation of the chemical shifts from the proton located inside the cavity (H-3, H-5 and H-6) coupled

  20. Quantitative analysis of sugars in wood hydrolyzates with 1H NMR during the autohydrolysis of hardwoods

    Microsoft Academic Search

    Ashutosh Mittal; Gary M. Scott; Thomas E. Amidon; David J. Kiemle; Arthur J. Stipanovic

    2009-01-01

    The focus of this work was to determine the utility of 1H NMR spectroscopy in the quantification of sugars resulting from the solubilization of hemicelluloses during the autohydrolysis of hardwoods and the use of this technique to evaluate the kinetics of this process over a range of temperatures and times. Yields of residual xylan, xylooligomers, xylose, glucose, and the degraded

  1. On the measurement of 15N-{1H} nuclear Overhauser effects.

    PubMed

    Ferrage, Fabien; Piserchio, Andrea; Cowburn, David; Ghose, Ranajeet

    2008-06-01

    Accurate quantification of the 15N-{1H} steady-state NOE is central to current methods for the elucidation of protein backbone dynamics on the fast, sub-nanosecond time scale. This experiment is highly susceptible to systematic errors arising from multiple sources. The nature of these errors and their effects on the determined NOE ratio is evaluated by a detailed analysis of the spin dynamics during the pair of experiments used to measure this ratio and possible improvements suggested. The experiment that includes 1H irradiation, is analyzed in the framework of Average Liouvillian Theory and a modified saturation scheme that generates a stable steady-state and eliminates the need to completely saturate 1H nuclei is presented. The largest source of error, however, in 1H-dilute systems at ultra-high fields is found to be an overestimation of the steady-state NOE value as a consequence of the incomplete equilibration of the magnetization in the so-called "reference experiment". The use of very long relaxation delays is usually an effective, but time consuming, solution. Here, we introduce an alternative reference experiment, designed for larger, deuterated systems, that uses the fastest relaxing component of the longitudinal magnetization as a closer approximation to the equilibrium state for shorter relaxation delays. The utility of the modified approach is illustrated through simulations on realistic spin systems over a wide range of time scales and experimentally verified using a perdeuterated sample of human ubiquitin. PMID:18417394

  2. On the Measurement of 15N-{1H} Nuclear Overhauser Effects

    PubMed Central

    Ferrage, Fabien; Piserchio, Andrea; Cowburn, David; Ghose, Ranajeet

    2009-01-01

    Accurate quantification of the 15N-{1H} steady-state NOE is central to current methods for the elucidation of protein backbone dynamics on the fast, sub-nanosecond timescale. This experiment is highly susceptible to systematic errors arising from multiple sources. The nature of these errors and their effects on the determined NOE ratio is evaluated by a detailed analysis of the spin dynamics during the pair of experiments used to measure this ratio and possible improvements suggested. The experiment that includes 1H irradiation, is analyzed in the framework of Average Liouvillian Theory and a modified saturation scheme that generates a stable steady state and eliminates the need to completely saturate 1H nuclei, is presented. The largest source of error, however, in 1H-dilute systems at ultra-high fields is found to be an overestimation of the steady-state NOE value as a consequence of the incomplete equilibration of the magnetization in the so-called “reference experiment”. The use of very long relaxation delays is usually an effective, but time consuming, solution. Here, we introduce an alternative reference experiment, designed for larger, deuterated systems, that uses the fastest relaxing component of the longitudinal magnetization a closer approximation to the equilibrium state for shorter relaxation delays. The utility of the modified approach is illustrated through simulations on realistic spin-systems over a wide range of timescales and experimentally verified using a perdeuterated sample of human ubiquitin. PMID:18417394

  3. GPS Time Synchronization System for K2K 1 H. G. Berns and R. J. Wilkes

    E-print Network

    Berns, Hans-Gerd

    GPS Time Synchronization System for K2K 1 H. G. Berns and R. J. Wilkes Department of Physics System (GPS) provides a means for satisfying this requirement at very low cost. In addition to low­resolution time data (day of year, hour, minute, second), commercial GPS receivers output a 1 pulse per sec (1PPS

  4. GPS Time Synchronization System for K2K1 H. G. Berns and R. J. Wilkes

    E-print Network

    Berns, Hans-Gerd

    GPS Time Synchronization System for K2K1 H. G. Berns and R. J. Wilkes Department of Physics System (GPS) provides a means for satisfying this requirement at very low cost. In addition to low- resolution time data (day of year, hour, minute, second), commercial GPS receivers output a 1 pulse per sec

  5. Application of chemometrics to the 1H NMR spectra of apple juices: discrimination between apple varieties

    Microsoft Academic Search

    Peter S Belton; Ian J Colquhoun; E. Katherine Kemsley; Ivonne Delgadillo; Paula Roma; M. John Dennis; Matthew Sharman; Elaine Holmes; Jeremy K Nicholson; Manfred Spraul

    1998-01-01

    Discrimination between apple juices produced from different varieties (Spartan, Bramley, Russet) has been achieved by applying principal components analysis (PCA) and linear discriminant analysis to 1H NMR spectra of the juices. The use of covariance and correlation matrix PCA methods was investigated and different regions of the spectrum were analysed in view of the large range of signal intensities. All

  6. Synthesis of stereospecifically deuterated desoxypodophyllotoxins and 1H-nmr assignment of desoxypodophyllotoxin

    NASA Technical Reports Server (NTRS)

    Pullockaran, A. J.; Kingston, D. G.; Lewis, N. G.

    1989-01-01

    [4 beta- 2H1]Desoxypodophyllotoxin [3], [4 alpha- 2H1]desoxypodophyllotoxin [4], and [4, 4- 2 H2]desoxypodophyllotoxin [9] were prepared from podophyllotoxin [1] via its chloride [5]. A complete assignment of the 1H-nmr spectrum of desoxypodophyllotoxin [2] was made on the basis of the spectra of the deuterated compounds [3] and [4].

  7. Characterisation of crosslinked elastomeric materials by 1H NMR relaxation time distributions

    Microsoft Academic Search

    G. C Borgia; P Fantazzini; A Ferrando; G Maddinelli

    2001-01-01

    One of the most critical structural parameters in elastomeric materials is the density of cross-linking between the polymeric chains. This chemical feature greatly affects chain motions and is determinant in controlling mechanical properties of the final product. NMR techniques are widely and efficiently applied to investigation of such materials. In this study we have measured both transverse and longitudinal 1H

  8. Polarization quantum beat spectroscopy of HCF,,A~ 1 H hyperfine structure and Zeeman effect

    E-print Network

    Reid, Scott A.

    and Zeeman effect Haiyan Fan, Ionela Ionescu, Ju Xin,a) and Scott A. Reidb) Department of Chemistry investigate the 19 F and 1 H nuclear hyperfine structure and Zeeman effect in the simplest singlet carbene or Zeeman effect in this system, which are detailed probes of the elec- tronic structure and important

  9. NMR resonance splitting of urea in stretched hydrogels: Proton exchange and 1H/2H isotopologues

    NASA Astrophysics Data System (ADS)

    Kuchel, Philip W.; Naumann, Christoph; Chapman, Bogdan E.; Shishmarev, Dmitry; Håkansson, Pär; Bacskay, George; Hush, Noel S.

    2014-10-01

    Urea at ?12 M in concentrated gelatin gel, that was stretched, gave 1H and 2H NMR spectral splitting patterns that varied in a predictable way with changes in the relative proportions of 1H2O and 2H2O in the medium. This required consideration of the combinatorics of the two amide groups in urea that have a total of four protonation/deuteration sites giving rise to 16 different isotopologues, if all the atoms were separately identifiable. The rate constant that characterized the exchange of the protons with water was estimated by back-transformation analysis of 2D-EXSY spectra. There was no 1H NMR spectral evidence that the chiral gelatin medium had caused in-equivalence in the protons bonded to each amide nitrogen atom. The spectral splitting patterns in 1H and 2H NMR spectra were accounted for by intra-molecular scalar and dipolar interactions, and quadrupolar interactions with the electric field gradients of the gelatin matrix, respectively.

  10. Refereed Journal Publications (1) H. Winkler: Integral representations for stochastic processes with n-th sta-

    E-print Network

    Knobloch,Jürgen

    Refereed Journal Publications (1) H. Winkler: Integral representations for stochastic processes with n-th sta- tionary increments. Math. Nachr. 163 (1993), 35 - 44. (2) H. Winkler: The inverse spectral problem for canonical systems. Integral Equations Oper. Theory 22 (1995), 360 - 374. (3) H. Winkler

  11. Process Semantics of General Inhibitor Nets1 H. C. M. Kleijn

    E-print Network

    Newcastle upon Tyne, University of

    Process Semantics of General Inhibitor Nets1 H. C. M. Kleijn LIACS, Leiden University P.O.Box 9512 a causality semantics of Place/Transition nets with weighted inhibitor arcs (PTI-nets). We extend the standard approach to defining the partial order semantics of Place/Transition nets (PT-nets) based on the process

  12. Magnesium silicate dissolution investigated by 29Si MAS, 1H-29Si CPMAS, 25Mg QCPMG, and 1H-25Mg CP QCPMG NMR.

    PubMed

    Davis, Michael C; Brouwer, William J; Wesolowski, David J; Anovitz, Lawrence M; Lipton, Andrew S; Mueller, Karl T

    2009-08-28

    Olivine-(Mg,Fe)(2)SiO(4)-has been the subject of frequent investigation in the earth sciences because of its simple structure and rapid dissolution kinetics. Several studies have observed a preferential release of the divalent cation with respect to silicon during weathering under acidic conditions, which has been correlated to the formation of a silicon-rich leached layer. While leached layer formation has been inferred through the changing solution chemistry, a thorough spectroscopic investigation of olivine reacted under acidic conditions has not been conducted. The pure magnesium end member of the olivine series (forsterite-Mg(2)SiO(4)) was chosen for detailed investigations in this study because paramagnetic iron hinders NMR investigations by providing an extra mode of relaxation for neighboring nuclei, causing lineshapes to become significantly broadened and unobservable in the NMR spectrum. For reacting forsterite, spectroscopic interrogations using nuclear magnetic resonance (NMR) can elucidate the changing magnesium coordination and bonding environment. In this study, we combine analysis of the changing solution chemistry with advanced NMR techniques ((29)Si MAS, (1)H-(29)Si CP MAS, (25)Mg QCPMG, and (1)H-(25)Mg CP QCPMG NMR) to probe leached layer formation and secondary phase precipitation during the dissolution of forsterite at 150 degrees C. PMID:19652836

  13. The structure of alloys and the phase equilibrium diagram of the Zr-Ru-Ir system. V. Plan of crystallization of alloys of the Zr-ZrRu-ZrIr partial system

    SciTech Connect

    Eremenko, V.N.; Khorvzhaya, V.G.; Shtepa, T.D.

    1986-06-01

    This paper presents a plan of the reactions occurring in crystallization of alloys of the Zr-ZrRu-ZrIR partial system and the phase composition and structural constituents of as-cast alloys of the system. A correct and full confirmation of the certainty of the phase equilibria established in the Zr-ZrRu-ZrIR system was the result of differential thermal analysis made on specimens selected from the most complex areas of crystallization of the alloys and annealed at 1000 C after preliminary homogenization of them at higher temperatures.

  14. High resolution 1H nuclear magnetic resonance of a transmembrane peptide.

    PubMed Central

    Davis, J. H.; Auger, M.; Hodges, R. S.

    1995-01-01

    Although the strong 1H-1H dipolar interaction is known to result in severe homogeneous broadening of the 1H nuclear magnetic resonance (NMR) spectra of ordered systems, in the fluid phase of biological and model membranes the rapid, axially symmetric reorientation of the molecules about the local bilayer normal projects the dipolar interaction onto the motional symmetry axis. Because the linewidth then scales as (3 cos2 theta-1)/2, where theta is the angle between the local bilayer normal and the magnetic field, the dipolar broadening has been reduced to an "inhomogeneous" broadening by the rapid axial reorientation. It is then possible to obtain high resolution 1H-NMR spectra of membrane components by using magic angle spinning (MAS). Although the rapid axial reorientation effectively eliminates the homogeneous dipolar broadening, including that due to n = 0 rotational resonances, the linewidths observed in both lipids and peptides are dominated by low frequency motions. For small peptides the most likely slow motions are either a "wobble" or reorientation of the molecular diffusion axis relative to the local bilayer normal, or the reorientation of the local bilayer normal itself through surface undulations or lateral diffusion over the curved surface. These motions render the peptide 1H-NMR lines too broad to be observed at low spinning speeds. However, the linewidths due to these slow motions are very sensitive to spinning rate, so that at higher speeds the lines become readily visible. The synthetic amphiphilic peptide K2GL20K2A-amide (peptide-20) has been incorporated into bilayers of 1,2-di-d 27-myristoyl-sn-glycero-3-phosphocholine (DMPC-d54) and studied by high speed 1H-MAS-NMR. The linewidths observed for this transbilayer peptide, although too broad to be observable at spinning rates below -5 kHz, are reduced to 68 Hz at a spinning speed of 14 kHz (at 500C). Further improvements in spinning speed and modifications in sample composition designed to reduce the effectiveness of the slow motions responsible for the linewidth should result in significant further reduction in peptide linewidths. With this technique, there is now the potential for the use of 1H-MAS-NMR for the study of conformation, folding, and dynamics of small membrane peptides and protein fragments. PMID:8580335

  15. Crystallographic and magnetic properties of Pb2?xBixIr2O7?? (0 ? x ? 2)

    NASA Astrophysics Data System (ADS)

    Retuerto, M.; Sarkar, T.; Li, M.-R.; Ignatov, A.; Croft, M.; Hodges, J. P.; Thao Tran, T.; Shiv Halasyamani, P.; Greenblatt, M.

    2014-12-01

    The title series of compounds have been synthesized by solid state reaction and characterized by x-ray diffraction (PXD), neutron powder diffraction (PND), second harmonic generation (SHG), x-ray absorption spectroscopy (XAS) and magnetization measurements. The crystal structures have been refined from PND data in the centrosymmetric space group Fd\\bar{3}m with pyrochlore structure. No sign of a break of the centrosymmetry has been observed by SHG and no change of the structure to a polar space group in any component of the series, as it was previously reported for Pb2Ir2O7?? with non-centrosymmetric F\\bar{4}3m space group. We have determined by PND that the oxidation state of Ir is slightly decreasing from 5+-to-4+ in the Pb-rich to almost 4+ in the Bi-rich samples. This evolution is confirmed by XAS and also it explains the progression of the crystallographic parameters. All the samples are paramagnetic in the temperature range measured and the magnitude of the effective magnetic moment is enhanced with Bi content, correlated with the enhancement of Ir4+ compared to Ir5+; suggesting Ir5+ to be present in a trigonal antiprism crystal field splitting and therefore Ir4+ as the only magnetic cation.

  16. Design and build of the Brillant Pebbles Passive IR sensor

    Microsoft Academic Search

    John Hoschette; Bob Murphy; Art Leary; Walt Watson; Tim White

    1993-01-01

    This paper describes the design, construction, and preflight certification testing of the Brilliant Pebbles Passive IR sensor. The passive IR sensor is comprised of a 64 x 64 HgCdTe hybrid focal plane array, cassegrain telescope, switchable filter and compensating electronics. The switchable filter allows the passive IR sensor to image in the Midwave or Long-wave IR bands. The sensor performance

  17. ALTAIR: Automatic Location Tracking system with Active IR-tag

    Microsoft Academic Search

    Muneyuki Sakata; Yoshihiro Yasumuro; Masataka Imura; Yoshitsugu Manabe; Osamu Oshiro; Kunihiro Chihara

    2003-01-01

    This paper proposes a new location-awareness system, ALTAIR (Automatic Location Tracking system with Active IR-tag) that automatically detects and tracks the locations of the mobile PC (Personal Computer) users. IR(InfraRed)-tag is stably detected and distinguished from the scenery by IR filtering camera. Combination of the IR-tag and wireless LAN (Local Area Network) enables ALTAIR to control the timing and the

  18. The insulin signalling system and the IRS proteins

    Microsoft Academic Search

    M. F. White

    1997-01-01

    Summary   During the past few years, the insulin signalling system has emerged as a flexible network of interacting proteins. By utilizing\\u000a the insulin receptor substrate (IRS)-proteins (IRS-1 and IRS-2), the insulin signal can be amplified or attenuated independently\\u000a of insulin binding and tyrosine kinase activity, providing an extensible mechanism for signal transmission in multiple cellular\\u000a backgrounds. By employing IRS-proteins to

  19. Reactions of N-alkylazinium cations. 3. Quaternary pteridinium salts. Synthesis, structure, and reactions with simple nucleophiles

    SciTech Connect

    Kazantseva, I.V.; Charushin, V.N.; Chuapkhin, O.N.; Chernyshev, A.I.; Esipov, S.E.

    1986-03-01

    4-Morpholinopteridine reacts with triethyloxonium tetra-fluoroborate to give two types of isomeric quaternary salts, viz., 1-ethyl- and 8-ethyl-4-morpholinopteridinium tetrafluoroborates. The structures of the pteridinium cations were provided by the /sup 1/H and /sup 13/C NMR spectra and also by chemical transformations in reactions with simple nucleophiles.

  20. IR filters for TPV converter modules

    NASA Astrophysics Data System (ADS)

    Horne, W. E.; Morgan, M. D.; Sundaram, V. S.

    1996-03-01

    This paper presents a TPV converter module for use with radioisotope heat sources such as the Department of Energy's General Purpose Heat Source (GPHS). The converter module utilizes an IR bandpass filter which transmits a band of energy at the optimum frequency for GaSb photovoltaic conversion and rejects long wavelength out of band energy with a broadband reflectance of greater than 98%. Recent progress in optimizing IR bandpass filters and photovoltaic cells for use in the TPV module is summarized. Measured data on the transmittance and reflectance of the filters, quantum efficiency of the PV cells both with and without the filters are presented. The results of using these measured results in an experimentally confirmed analytical model of the TPV converter module to calculate the performance of the optimized components are discussed. An economical pilot process for filter production is also described.

  1. Translational diffusion in paramagnetic liquids by 1H NMR relaxometry: Nitroxide radicals in solution

    NASA Astrophysics Data System (ADS)

    Kruk, D.; Korpa?a, A.; Kubica, A.; Meier, R.; Rössler, E. A.; Moscicki, J.

    2013-01-01

    For nitroxide radicals in solution one can identify three frequency regimes in which 1H spin-lattice relaxation rate of solvent molecules depend linearly on square root of the 1H resonance frequency. Combining a recently developed theory of nuclear (proton) spin-lattice relaxation in solutions of nitroxide radicals [D. Kruk et al., J. Chem. Phys. 137, 044512 (2012)], 10.1063/1.4736854 with properties of the spectral density function associated with translational dynamics, relationships between the corresponding linear changes of the relaxation rate (for 14N spin probes) and relative translational diffusion coefficient of the solvent and solute molecules have been derived (in analogy to 15N spin probes [E. Belorizky et al., J. Phys. Chem. A 102, 3674 (1998)], 10.1021/jp980397h). This method allows a simple and straightforward determination of diffusion coefficients in spin-labeled systems, by means of 1H nuclear magnetic resonance (NMR) relaxometry. The approach has thoroughly been tested by applying to a large set of experimental data—1H spin-lattice relaxation dispersion results for solutions of different viscosity (decalin, glycerol, propylene glycol) of 14N and 15N spin probes. The experiments have been performed versus temperature (to cover a broad range of translational diffusion coefficients) using field cycling spectrometer which covers three decades in 1H resonance frequency, 10 kHz-20 MHz. The limitations of NMR relaxometry caused by the time scale of the translational dynamics as well as electron spin relaxation have been discussed. It has been shown that for spin-labeled systems NMR relaxometry gives access to considerably faster diffusion processes than for diamagnetic systems.

  2. Growth of graphene on Ir(111)

    Microsoft Academic Search

    Johann Coraux; Alpha T. N'Diaye; Martin Engler; Carsten Busse; Dirk Wall; Niemma Buckanie; Frank-J. Meyer zu Heringdorf; Raoul van Gastel; Bene Poelsema; Thomas Michely

    2009-01-01

    Catalytic decomposition of hydrocarbons on transition metals attracts a renewed interest as a route toward high-quality graphene prepared in a reproducible manner. Here we employ two growth methods for graphene on Ir(111), namely room temperature adsorption and thermal decomposition at 870-1470 K (temperature programmed growth (TPG)) as well as direct exposure of the hot substrate at 870-1320 K (chemical vapor

  3. Spitzer IRS Observations of FU Orionis Objects

    Microsoft Academic Search

    J. D. Green; L. Hartmann; N. Calvet; D. M. Watson; M. Ibrahimov; E. Furlan; B. Sargent; W. J. Forrest

    2006-01-01

    We present 5-35 mum spectra, taken with the Infrared Spectrograph (IRS) on the Spitzer Space Telescope, of five FU Orionis objects: FU Ori, V1515 Cyg, V1057 Cyg, BBW 76, and V346 Nor. All but V346 Nor reveal amorphous silicate grains in emission at 10 and 20 mum, and show water-vapor absorption bands at 5.8 and 6.8 mum and SiO or

  4. WFC3 SS IR Fine Alignment

    NASA Astrophysics Data System (ADS)

    MacKenty, John

    2012-10-01

    Part of side switch activities.The corrector mechanism will be used to bring the IR channel of WFC3 into optimal alignment with the OTA using analysis of star images over the field. Two visits are required; corrector offsets will be uplinked after each visit via realtime command.The execution of this proposal is contingent upon the need for internal alignment and cannot be executed with out permission from the PI, Dr. John MacKenty.ID: WF22

  5. Methane Line Intensities: Near and Far IR

    NASA Astrophysics Data System (ADS)

    Brown, Linda R.; Devi, V. Malathy; Wishnow, Edward H.; Sung, Keeyoon; Crawford, Timothy J.; Mantz, Arlan W.; Smith, Mary Ann H.; Predoi-Cross, Adriana; Benner, D. Chris

    2014-11-01

    Accurate knowledge of line intensities is crucial input for radiance calculations to interpret atmospheric observations of planets and moons. We have therefore undertaken extensive laboratory studies to measure the methane spectrum line-by-line in order to improve theoretical quantum mechanical modeling for molecular spectroscopy databases (e. g. HITRAN and GEISA) used by planetary astronomers. Preliminary results will be presented for selected ro-vibrational transitions in both the near-IR (1.66 and 2.2 - 2.4 microns) and the far-IR (80 - 120 microns) regions. For this, we have recorded high-resolution spectra (instrumental resolving power: 1,300,000 (NIR) and 10,000 (FIR)) with the Bruker 125HR Fourier transform spectrometer at JPL using isotopically-enriched 12CH4 and 13CH4, as well as normal methane samples. For the NIR wavelengths, three different absorption cells have been employed to achieve sample temperatures ranging from 78 K to 299 K: 1) a White cell set to a path length of 13.09 m for room temperature data, 2) a single-pass 0.2038 m cold cell and 3) a new coolable Herriott cell with a fixed 20.941 m optical path and configured for the first time to a FT-IR spectrometer. For the Far-IR, another coolable absorption chamber set to a 52 m optical path has been used. These new experiments and intensity measurements will be presented and discussed.Part of the research described in this paper was performed at the Jet Propulsion Laboratory, California Institute of Technology, the University of California, Berkeley, Connecticut College, and NASA Langley under contracts and grants with the National Aeronautics and Space Administration. A. Predoi-Cross and her research group have been supported by the National Science and Engineering Research Council of Canada.

  6. Kinetics of in vitro digestion of starches monitored by time-resolved (1)H Nuclear Magnetic Resonance.

    PubMed

    Dona, Anthony C; Pages, Guilhem; Gilbert, Robert G; Gaborieau, Marianne; Kuchel, Philip W

    2009-03-01

    A (1)H NMR method is presented that monitors the initial and later stages of in vitro enzymatic digestion of starch suspensions. It allows, for the first time to our knowledge, the accurate analysis of the initial 5% of the extent of hydrolysis. This is significant because rapidly digested starch produces glucose that determines the blood glucose concentration immediately after ingestion of food. The two key hydrolytic enzymes, alpha-amylase and amyloglucosidase, showed clear systematic deviation from Michaelis-Menten kinetics as the starch or wheat flour substrate that was used changed its character during the reaction. Estimates of Michaelis-Menten parameters for amyloglucosidase and alpha-amylase were successfully found by analyzing two stages of digestion separately. The Michaelis-Menten constants for purified starch were (6.4 +/- 0.8) and (1.1 +/- 0.3) g dL(-1) (% w/v), respectively; and the maximum velocities of glucose release by amyloglucosidase, and short oligoglucosides and glucose by alpha-amylase were (1.9 +/- 0.4) x 10(-2) and (1.6 +/- 0.2) x 10(-2) mmol L(-1) s(-1) for the first stage of digestion, and (9.0 +/- 1.0) x 10(-3) and (4.7 +/- 1.4) x 10(-3) mmol L(-1) s(-1) for the second stage, giving a ratio of the two V(max) values of 2.1 and 3.4, respectively. PMID:19209867

  7. Demonstration of KHILS two-color IR projection capability

    Microsoft Academic Search

    Lawrence E. Jones; Jason S. Coker; Dennis L. Garbo; Eric M. Olson; Robert Lee Murrer; Thomas P. Bergin; George C. Goldsmith; Dennis R. Crow; Andrew W. Guertin; Michael Dougherty; Thomas M. Marler; Virgil G. Timms

    1998-01-01

    For more than a decade, there has been considerable discussion about using different IR bands for the detection of low contrast military targets. Theory predicts that a target can have little to no contrast against the background in one IR band while having a discernible signature in another IR band. A significant amount of effort has been invested towards establishing

  8. IR Cards: Inquiry-Based Introduction to Infrared Spectroscopy

    ERIC Educational Resources Information Center

    Bennett, Jacqueline; Forster, Tabetha

    2010-01-01

    As infrared spectroscopy (IR) is frequently used in undergraduate organic chemistry courses, an inductive introduction to IR spectroscopy that uses index cards printed with spectra, structures, and chemical names is described. Groups of students are given an alphabetized deck of these "IR cards" to sort into functional groups. The students then…

  9. 22 CFR 213.36 - Reporting to IRS.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 false Reporting to IRS. 213.36 Section 213.36 Foreign...Requirements § 213.36 Reporting to IRS. Upon discharge of an indebtedness, USAID will report the discharge to the IRS in accordance with the requirements...

  10. 22 CFR 213.36 - Reporting to IRS.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 false Reporting to IRS. 213.36 Section 213.36 Foreign...Requirements § 213.36 Reporting to IRS. Upon discharge of an indebtedness, USAID will report the discharge to the IRS in accordance with the requirements...

  11. 22 CFR 213.36 - Reporting to IRS.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 2014-04-01 false Reporting to IRS. 213.36 Section 213.36 Foreign...Requirements § 213.36 Reporting to IRS. Upon discharge of an indebtedness, USAID will report the discharge to the IRS in accordance with the requirements...

  12. 22 CFR 213.36 - Reporting to IRS.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 false Reporting to IRS. 213.36 Section 213.36 Foreign...Requirements § 213.36 Reporting to IRS. Upon discharge of an indebtedness, USAID will report the discharge to the IRS in accordance with the requirements...

  13. 22 CFR 213.36 - Reporting to IRS.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Reporting to IRS. 213.36 Section 213.36 Foreign...Requirements § 213.36 Reporting to IRS. Upon discharge of an indebtedness, USAID will report the discharge to the IRS in accordance with the requirements...

  14. Operating temperature: a challenge for cooled IR technologies

    Microsoft Academic Search

    Michel Vuillermet; Philippe Tribolet

    2010-01-01

    Cooled IR technologies are challenged for answering new system needs like the reduction of energy. This reduction is requested in new IR system design in particular for cooled IR detection. The goal is to reduce system sizes, to increase system autonomies and reliabilities and globally to reduce system costs! One of the key drivers for cooled systems is the cooler

  15. IR evaluation methods for retrieving highly relevant documents

    Microsoft Academic Search

    Kalervo Järvelin; Jaana Kekäläinen

    2000-01-01

    This paper proposes evaluation methods based on the use of non-dichotomous relevance judgements in IR experiments. It is argued that evaluation methods should credit IR methods for their ability to retrieve highly relevant documents. This is desirable from the user point of view in modern large IR environments. The proposed methods are (1) a novel application of P-R curves and

  16. Formamidine Reactions

    E-print Network

    Griffin, E. L.

    1913-05-15

    of Hantzsch. (1), and the method of Uhlenhuth (2) was found to be not very much more satisfactory owing to the fact that the methyl lsoxazolon broKe down too much on heating Better results were obtained when the oxime of acetoacetic ester was obtained...,C ~ CH RNrOM-SHR = CH.C - C::CHHKR * li , II I H-0- CO U-0- CO * E2sTHx since methyl lsoxazolon is made by the reaction of hydroxylamine hydrochlorid on acetoacetic ester, it was thought that it might be possible to maKe the amldo methylene...

  17. Recent developments in uncooled IR technology

    NASA Astrophysics Data System (ADS)

    Murphy, Robert; Kohin, Margaret; Backer, Brian S.; Butler, Neal R.; Blackwell, Richard; Allen, Tom

    2000-07-01

    Sanders IR Imaging Systems (IRIS), a Lockheed Martin Company, has made recent improvements in high performance uncooled IR focal plane arrays and systems. This paper provides performance results for three of these new FPAs and systems. First we discuss a new 320 X 240, 46 micrometer pitch FPA, which when put into a system with a transmission of 74%, will provide a system NETD of < 26 mK (F/0.8, 60 Hz). This FPA has a power of < 250 mW (which includes on-chip 14 bit analog to digital conversion), and virtually no crosstalk from saturation. Second, we discuss the first ever 640 X 480 element uncooled IR camera. This camera, which is based on a 28 micrometer pitch microbolometer staring FPA, produces a system sensitivity of < 150 mK, (F/1, 30 Hz) and has a Minimum Resolvable Temperature Difference of < 0.4 degrees Celsius at the Nyquist frequency. Finally, we have developed a new lightweight thermal weapons sight (TWS). Our TWS, which weighs < 3 lbs. (with battery) and operates over the -37 degrees Celsius to +49 degrees Celsius temperature range, has demonstrated a boresight retention of < 0.2 mrad after 1000's of rounds were fired.

  18. SXGA resolution IR sensor: STAIRS C

    NASA Astrophysics Data System (ADS)

    Crawford, Stewart; Mcdonald, John P.; Glass, Adrian W.; Dennis, Peter N. J.

    2002-07-01

    In engagement scenarios increasing battlefield emphasis on the trade-off between long stand-off ranges, adverse weather capability and high probability target identification has resulted in the need for an SXGA resolution IR Sensor. Leading on from previous collaborative work with QinetiQ (formerly the UK Defence Evaluation and Research Agency) the UK MoD has awarded a contract, the STAIRS C programme, to Thales Optronics to develop to production such an IR Sensor thus ensuring this leading technology is available to meet the needs of advanced weapon systems and platforms of the future. A UK industry team has been formed to implement an optimisation programme for the productionisation and future applications of STAIRS C modules and the first of a number of UK MoD programmes has selected STAIRS C for a major Air Defence role. The STAIRS C programme has set the demanding requirement of doubling the target identification range of current in-service IR sensors whilst maintaining or improving the situational awareness (Field of View). The programme, technical specification and imaging capability achieved are reviewed in the paper.

  19. Controlled preparation and characterization of plurimetallic Pt–Sn and Pt–Ir–Sn\\/Al 2O 3 reforming catalysts

    Microsoft Academic Search

    C. Carnevillier; F. Epron; P. Marecot

    2004-01-01

    The preparation of bimetallic 0.6wt.% Pt–xwt.% Sn\\/Al2O3 and trimetallic 0.5wt.% Pt–0.1wt.% Ir–xwt.% Sn\\/Al2O3 and 0.3wt.% Pt–0.3wt.% Ir–xwt.% Sn\\/Al2O3 catalysts (0 reaction between hydrogen activated on a parent platinum or platinum–iridium catalyst and tin chloride (SnCl4) dissolved in hydrochloric medium (“catalytic reduction” method) was investigated. Elemental analysis of catalysts indicated that tin can be deposited

  20. Sequential Au(I)-catalyzed reaction of water with o-acetylenyl-substituted phenyldiazoacetates

    PubMed Central

    Zhou, Lei; Liu, Yizhou; Zhang, Yan

    2011-01-01

    Summary The gold(I)-catalyzed reaction of water with o-acetylenyl-substituted phenyldiazoacetates provides 1H-isochromene derivatives in good yields. The reaction follows a catalytic sequence of gold carbene formation/water O–H insertion/alcohol-alkyne cyclization. The gold(I) complex is the only catalyst in each of these steps. PMID:21647254