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Sample records for 1h-1h cosy hmqc

  1. Systematic Evaluation of Non-Uniform Sampling Parameters in the Targeted Analysis of Urine Metabolites by 1H,1H 2D NMR Spectroscopy.

    PubMed

    Schlippenbach, Trixi von; Oefner, Peter J; Gronwald, Wolfram

    2018-03-09

    Non-uniform sampling (NUS) allows the accelerated acquisition of multidimensional NMR spectra. The aim of this contribution was the systematic evaluation of the impact of various quantitative NUS parameters on the accuracy and precision of 2D NMR measurements of urinary metabolites. Urine aliquots spiked with varying concentrations (15.6-500.0 µM) of tryptophan, tyrosine, glutamine, glutamic acid, lactic acid, and threonine, which can only be resolved fully by 2D NMR, were used to assess the influence of the sampling scheme, reconstruction algorithm, amount of omitted data points, and seed value on the quantitative performance of NUS in 1 H, 1 H-TOCSY and 1 H, 1 H-COSY45 NMR spectroscopy. Sinusoidal Poisson-gap sampling and a compressed sensing approach employing the iterative re-weighted least squares method for spectral reconstruction allowed a 50% reduction in measurement time while maintaining sufficient quantitative accuracy and precision for both types of homonuclear 2D NMR spectroscopy. Together with other advances in instrument design, such as state-of-the-art cryogenic probes, use of 2D NMR spectroscopy in large biomedical cohort studies seems feasible.

  2. Long-range 1H-1H NMR correlation: extending connectivities to remote bonds via an intermediate heterospin.

    PubMed

    Parella, Teodor; Espinosa, Juan Félix

    2008-05-01

    An out-and-stay 2D proton-proton NMR correlation experiment is proposed to detect long-range proton-proton connectivities up to six and seven bonds away. The magnetization flow pathway is based on a consecutive, dual-step J(CH)-transfer mechanism and it allows one to trace out (1)H-(1)H connectivities between protons belonging to different spin systems. This novel experimental scheme will be particularly useful in cases when carbon resonances overlap, providing connectivity information that could not be obtained in a HMBC experiment. The success of the experiment is demonstrated in the structural studies of a wide variety of chemical compounds. 2008 John Wiley & Sons, Ltd.

  3. Hydrophobization of epoxy nanocomposite surface with 1H,1H,2H,2H-perfluorooctyltrichlorosilane for superhydrophobic properties

    NASA Astrophysics Data System (ADS)

    Psarski, Maciej; Marczak, Jacek; Celichowski, Grzegorz; Sobieraj, Grzegorz B.; Gumowski, Konrad; Zhou, Feng; Liu, Weimin

    2012-10-01

    Nature inspires the design of synthetic materials with superhydrophobic properties, which can be used for applications ranging from self-cleaning surfaces to microfluidic devices. Their water repellent properties are due to hierarchical (micrometer- and nanometre-scale) surface morphological structures, either made of hydrophobic substances or hydrophobized by appropriate surface treatment. In this work, the efficiency of two surface treatment procedures, with a hydrophobic fluoropolymer, synthesized and deposited from 1H,1H,2H,2H-perfluorooctyltrichlorosilane (PFOTS) is investigated. The procedures involved reactions from the gas and liquid phases of the PFOTS/hexane solutions. The hierarchical structure is created in an epoxy nanocomposite surface, by filling the resin with alumina nanoparticles and micron-sized glass beads and subsequent sandblasting with corundum microparticles. The chemical structure of the deposited fluoropolymer was examined using XPS spectroscopy. The topography of the modified surfaces was characterized using scanning electron microscopy (SEM), and atomic force microscopy (AFM). The hydrophobic properties of the modified surfaces were investigated by water contact and sliding angles measurements. The surfaces exhibited water contact angles of above 150° for both modification procedures, however only the gas phase modification provided the non-sticking behaviour of water droplets (sliding angle of 3°). The discrepancy is attributed to extra surface roughness provided by the latter procedure.

  4. 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.

  5. Fast and simultaneous determination of 1 H-1 H and 1 H-19 F scalar couplings in complex spin systems: Application of PSYCHE homonuclear broadband decoupling.

    PubMed

    Kakita, Veera Mohana Rao; Rachineni, Kavitha; Hosur, Ramakrishna V

    2017-07-21

    The present manuscript focuses on fast and simultaneous determination of 1 H- 1 H and 1 H- 19 F scalar couplings in fluorinated complex steroid molecules. Incorporation of broadband PSYCHE homonuclear decoupling in the indirect dimension of zero-quantum filtered diagonal experiments (F1-PSYCHE-DIAG) suppresses 1 H- 1 H scalar couplings; however, it retains 1 H- 19 F scalar couplings (along F1 dimension) for the 19 F coupled protons while preserving the pure-shift nature for 1 H resonances uncoupled to 19 F. In such cases, along the direct dimensions, 1 H- 1 H scalar coupling multiplets deconvolute and they appear as duplicated multiplets for the 19 F coupled protons, which facilitates unambiguous discrimination of 19 F coupled 1 H chemical sites from the others. Further, as an added advantage, data acquisition has been accelerated by invoking the known ideas of spectral aliasing in the F1-PSYCHE-DIAG scheme and experiments demand only ~10 min of spectrometer times. Copyright © 2017 John Wiley & Sons, Ltd.

  6. Bioinspired, cysteamine-catalyzed co-silicification of (1H, 1H, 2H, 2HPerfluorooctyl) triethoxysilane and tetraethyl orthosilicate: formation of superhydrophobic surfaces.

    PubMed

    Park, Ji Hun; Kim, Ji Yup; Cho, Woo Kyung; Choi, Insung S

    2014-03-01

    Bioinspired silicification attracts a great deal of interest because of its physiologically relevant, mild conditions for hydrolysis and condensation of silica precursors, which makes the bioinspired approach superior to the conventional sol–gel process, particularly when dealing with biological entities. However, the morphological control of silica structures with incorporation of functional groups in the bioinspired silicilication has been unexplored. In this work, we co-silicificated (1H, 1H, 2H, 2H-perfluorooctyl)triethoxysilane and tetraethyl orthosilicate to investigate the morphological evolution of fluorinated silica structures in the cetyltrimethylammonium bromide-mediated, cysteamine-catalyzed silicification. The generated micrometer-long wormlike and spherical silica structures display superhydrophobicity after film formation. Interestingly, the measurement of dynamic water contact angles shows that the morphological difference leads to a different wetting state, either the self-cleaning or the pinning state of the superhydrophobic surface.

  7. Vicinal 1H-1H NMR coupling constants from density functional theory as reliable tools for stereochemical analysis of highly flexible multichiral center molecules.

    PubMed

    López-Vallejo, Fabian; Fragoso-Serrano, Mabel; Suárez-Ortiz, Gloria Alejandra; Hernández-Rojas, Adriana C; Cerda-García-Rojas, Carlos M; Pereda-Miranda, Rogelio

    2011-08-05

    A protocol for stereochemical analysis, based on the systematic comparison between theoretical and experimental vicinal (1)H-(1)H NMR coupling constants, was developed and applied to a series of flexible compounds (1-8) derived from the 6-heptenyl-5,6-dihydro-2H-pyran-2-one framework. The method included a broad conformational search, followed by geometry optimization at the DFT B3LYP/DGDZVP level, calculation of the vibrational frequencies, thermochemical parameters, magnetic shielding tensors, and the total NMR spin-spin coupling constants. Three scaling factors, depending on the carbon atom hybridizations, were found for the (1)H-C-C-(1)H vicinal coupling constants: f((sp3)-(sp3)) = 0.910, f((sp3)-(sp2)) = 0.929, and f((sp2)-(sp2))= 0.977. A remarkable correlation between the theoretical (J(pre)) and experimental (1)H-(1)H NMR (J(exp)) coupling constants for spicigerolide (1), a cytotoxic natural product, and some of its synthetic stereoisomers (2-4) demonstrated the predictive value of this approach for the stereochemical assignment of highly flexible compounds containing multiple chiral centers. The stereochemistry of two natural 6-heptenyl-5,6-dihydro-2H-pyran-2-ones (14 and 15) containing diverse functional groups in the heptenyl side chain was also analyzed by application of this combined theoretical and experimental approach, confirming its reliability. Additionally, a geometrical analysis for the conformations of 1-8 revealed that weak hydrogen bonds substantially guide the conformational behavior of the tetraacyloxy-6-heptenyl-2H-pyran-2-ones.

  8. Synthesis, characterization, and thermal analysis of a new energetic salt based on 1'-hydroxy-1H,1'H-5,5'-bitetrazol-1-olate

    NASA Astrophysics Data System (ADS)

    Niu, Chunhuan; Jin, Bo; Shang, Yu; Liu, Qiangqiang; Peng, Rufang

    2018-04-01

    4-Amino-1,2,4-triazolium 1'-hydroxy-1H,1'H-5,5'-bitetrazol-1-olate (ATHBTO) was synthesized by reacting 4-amino-1,2,4-triazole (AT) and 1H,1‧H-5,5‧-bistetrazole-1,1‧-diolate dihydrate (H2BTO.2H2O). Its crystal structure was characterized through single-crystal X-ray diffraction. Meanwhile, FTIR, 1H NMR, 13C NMR, and elemental analysis were also introduced to analyze its composition. The thermal stability was investigated by differential scanning calorimetry, thermogravimetric analysis, and thermogravimetric tandem infrared spectrum. Results indicated that ATHBTO exhibited excellent resistance to thermal decompositions reaching 511.4 K and had a 64.6% mass loss between 475.7 and 552.3 K. The kinetics parameters were calculated by Kissinger's method and Ozawa-Doyle's method. Moreover, according to the Kamlet-Jacobs formula, the calculated detonation velocity and detonation pressure of ATHBTO attained 8218 m/s and 28.69 GPa, respectively.

  9. Selective excitation enables assignment of proton resonances and (1)H-(1)H distance measurement in ultrafast magic angle spinning solid state NMR spectroscopy.

    PubMed

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-07-21

    Remarkable developments in ultrafast magic angle spinning (MAS) solid-state NMR spectroscopy enabled proton-based high-resolution multidimensional experiments on solids. To fully utilize the benefits rendered by proton-based ultrafast MAS experiments, assignment of (1)H resonances becomes absolutely necessary. Herein, we propose an approach to identify different proton peaks by using dipolar-coupled heteronuclei such as (13)C or (15)N. In this method, after the initial preparation of proton magnetization and cross-polarization to (13)C nuclei, transverse magnetization of desired (13)C nuclei is selectively prepared by using DANTE (Delays Alternating with Nutations for Tailored Excitation) sequence and then, it is transferred to bonded protons with a short-contact-time cross polarization. Our experimental results demonstrate that protons bonded to specific (13)C atoms can be identified and overlapping proton peaks can also be assigned. In contrast to the regular 2D HETCOR experiment, only a few 1D experiments are required for the complete assignment of peaks in the proton spectrum. Furthermore, the finite-pulse radio frequency driven recoupling sequence could be incorporated right after the selection of specific proton signals to monitor the intensity buildup for other proton signals. This enables the extraction of (1)H-(1)H distances between different pairs of protons. Therefore, we believe that the proposed method will greatly aid in fast assignment of peaks in proton spectra and will be useful in the development of proton-based multi-dimensional solid-state NMR experiments to study atomic-level resolution structure and dynamics of solids.

  10. High-resolution four-dimensional carbon-correlated 1H- 1H ROESY experiments employing isotags and the filter diagonalization method for effective assignment of glycosidic linkages in oligosaccharides

    NASA Astrophysics Data System (ADS)

    Armstrong, Geoffrey S.; Bendiak, Brad

    2006-07-01

    Four-dimensional nuclear magnetic resonance spectroscopy of oligosaccharides that correlates 1H-1H ROESY cross peaks to two additional 13C frequency dimensions is reported. The 13C frequencies were introduced by derivatization of all free hydroxyl groups with doubly 13C-labeled acetyl isotags. Pulse sequences were optimized for processing with the filter diagonalization method. The extensive overlap typically observed in 2D ROESY 1H-1H planes was alleviated by resolution of ROESY cross peaks in the two added dimensions associated with the carbon frequencies of the isotags. This enabled the interresidue 1H-1H ROESY cross peaks to be unambiguously assigned hence spatially proximate sugar spin systems across glycosidic bonds could be effectively ascertained. An experiment that selectively amplifies interresidue ROESY 1H-1H cross peaks is also reported. It moves the magnetization of an intraresidue proton normally correlated to a sugar H-1 signal orthogonally along the z axis prior to a Tr-ROESY mixing sequence. This virtually eliminates the incoherent intraresidue ROESY transfer, suppresses coherent TOCSY transfer, and markedly enhances the intensity of interresidue ROESY cross peaks.

  11. High-resolution four-dimensional carbon-correlated 1H-1H ROESY experiments employing isotags and the filter diagonalization method for effective assignment of glycosidic linkages in oligosaccharides.

    PubMed

    Armstrong, Geoffrey S; Bendiak, Brad

    2006-07-01

    Four-dimensional nuclear magnetic resonance spectroscopy of oligosaccharides that correlates 1H-1H ROESY cross peaks to two additional 13C frequency dimensions is reported. The 13C frequencies were introduced by derivatization of all free hydroxyl groups with doubly 13C-labeled acetyl isotags. Pulse sequences were optimized for processing with the filter diagonalization method. The extensive overlap typically observed in 2D ROESY 1H-1H planes was alleviated by resolution of ROESY cross peaks in the two added dimensions associated with the carbon frequencies of the isotags. This enabled the interresidue 1H-1H ROESY cross peaks to be unambiguously assigned hence spatially proximate sugar spin systems across glycosidic bonds could be effectively ascertained. An experiment that selectively amplifies interresidue ROESY 1H-1H cross peaks is also reported. It moves the magnetization of an intraresidue proton normally correlated to a sugar H-1 signal orthogonally along the z axis prior to a Tr-ROESY mixing sequence. This virtually eliminates the incoherent intraresidue ROESY transfer, suppresses coherent TOCSY transfer, and markedly enhances the intensity of interresidue ROESY cross peaks.

  12. Dehalogenation of vicinal dihalo compounds by 1,1'-bis(trimethylsilyl)-1H,1'H-4,4'-bipyridinylidene for giving alkenes and alkynes in a salt-free manner.

    PubMed

    Rej, Supriya; Pramanik, Suman; Tsurugi, Hayato; Mashima, Kazushi

    2017-12-07

    We report a transition metal-free dehalogenation of vicinal dihalo compounds by 1,1'-bis(trimethylsilyl)-1H,1'H-4,4'-bipyridinylidene (1) under mild conditions, in which trimethylsilyl halide and 4,4'-bipyridine were generated as byproducts. The synthetic protocol for this dehalogenation reaction was effective for a wide scope of dibromo compounds as substrates while keeping the various functional groups intact. Furthermore, the reduction of vicinal dichloro alkanes and vicinal dibromo alkenes also proceeded in a salt-free manner to afford the corresponding alkenes and alkynes.

  13. Polarization Facilities at COSY

    SciTech Connect

    Eversheim, Dieter

    2008-02-06

    The cooler synchrotron COSY at the Forschungszentrum Juelich, Germany has been equipped with all necessary tools to accelerate polarized protons and deuterons to their maximum energy. For the EDDA and ANKE experiments two atomic beam targets for polarized protons and deuterons have been installed in the COSY-ring. Tests of the RF Spin-Flipper have been very successful. Externally polarization experiments are carried out by the TOF spectrometer. The performance of the relevant components and experiments is discussed.

  14. Polarization Facilities at COSY

    NASA Astrophysics Data System (ADS)

    Eversheim, Dieter

    2008-02-01

    The cooler synchrotron COSY at the Forschungszentrum Jülich, Germany has been equipped with all necessary tools to accelerate polarized protons and deuterons to their maximum energy. For the EDDA and ANKE experiments two atomic beam targets for polarized protons and deuterons have been installed in the COSY-ring. Tests of the RF Spin-Flipper have been very successful. Externally polarization experiments are carried out by the TOF spectrometer. The performance of the relevant components and experiments is discussed.

  15. Strangeness Production at COSY

    SciTech Connect

    Hinterberger, Frank; Machner, Hartmut; Siudak, Regina

    2011-10-24

    The paper gives an overview of strangeness-production experiments at the Cooler Synchrotron COSY. Results on kaon-pair and {phi} meson production in pp, pd and dd collisions, hyperon-production experiments and {Lambda}p final-state interaction studies are presented.

  16. High efficiency ZnO-based dye-sensitized solar cells with a 1H,1H,2H,2H-perfluorodecyltriethoxysilane chain barrier for cutting on interfacial recombination

    NASA Astrophysics Data System (ADS)

    Xie, Yahong; Zhou, Xiaofeng; Mi, Hongyu; Ma, Junhong; Yang, Jianya; Cheng, Jian

    2018-03-01

    Charge recombination at the ZnO photoanode/electrolyte interface is one of the major limitations for high performance dye-sensitized solar cells (DSSCs) toward their theoretical power conversion efficiency (PCE). Here, we proposed an efficient approach for reducing this interfacial losses and consequently facilitating charge transfer by decorating a hydrophobic thin-film on the surface of the dye-coated zinc oxide photoanode via 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) hexane solution immersing. As a result, a high PCE of 8.22% was obtained, which far exceeded the efficiency of 5.40% in a conventional DSSC without PFDTES treatment. Furthermore, PFDTES treatment also largely elongated the lifetime of photogenerated electrons, and maintained a good photo-response at the photoelectrode. This work provides a comprehensive explanation of electron injection, transfer and recombination at the ZnO photoanode/electrolyte interface, and a promising strategy to explore high efficiency ZnO-based DSSCs.

  17. Deuteron polarimetry at COSY

    SciTech Connect

    Chiladze, D.; High Energy Physics Institute, Tbilisi State University, 0186 Tbilisi; Grigoriev, K.

    2007-06-13

    The vector Pz and tensor Pzz polarizations of a deuteron beam have been measured using elastic deuteron-carbon scattering at 75.6 MeV and deuteron-proton scattering at 270 MeV. After acceleration to 1170 MeV inside the COSY storage ring, the polarizations of the deuterons were remeasured by studying the analyzing powers of a variety of nuclear reactions at the ANKE magnetic spetrometer. The overall precisions obtained were about 4% for both Pz and Pzz. One of the motivation for the experimental programme is the direct reconstruction of the spin-dependent amplitudes, including relative phases, of large angle neutron-proton elastic scattering, through the studymore » of the p(d,2p)n charge-exchange reaction up to the highest available deuteron energy at COSY (2.3 GeV)« less

  18. 1H,1H,5H-Perfluoropentyl-1,1,2,2-tetrafluoroethylether as a co-solvent for high voltage LiNi1/3Co1/3Mn1/3O2/graphite cells

    NASA Astrophysics Data System (ADS)

    Wang, Chengyun; Zuo, Xiaoxi; Zhao, Minkai; Xiao, Xin; Yu, Le; Nan, Junmin

    2016-03-01

    1H,1H,5H-Perfluoropentyl-1,1,2,2-tetrafluoroethylether (F-EAE) mixed with ethylene carbonate (EC), diethyl carbonate (DEC), and lithium hexafluorophosphate (LiPF6) is evaluated as a co-solvent high-potential electrolyte of LiNi1/3Co1/3Mn1/3O2/graphite batteries. Linear sweep voltammetry (LSV) and cyclic voltammetry (CV) indicate that the EC/DEC-based electrolyte with F-EAE possesses a high oxidation potential (>5.2 V vs. Li/Li+) and excellent film-forming characteristics. With 40 wt% F-EAE in the electrolyte, the capacity retention of the LiNi1/3Co1/3Mn1/3O2/graphite pouch cells that are cycled between 3.0 and 4.5 V is significantly improved from 28.8% to 86.8% after 100 cycles. In addition, electrochemical impedance spectroscopy (EIS) of three-electrode pouch cells, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) are used to characterize the effects of F-EAE on the enhanced capacity retention. It is demonstrated that F-EAE facilitates the formation of a stable surface electrolyte interface (SEI) layer with low impedance on the anode and effectively suppresses an increase in the charge-transfer resistance on the cathode. These results suggest that F-EAE can serve as an alternative electrolyte solvent for 4.5 V high voltage rechargeable lithium-ion batteries.

  19. A Three-Dimensional DOSY HMQC Experiment for the High-Resolution Analysis of Complex Mixtures

    NASA Astrophysics Data System (ADS)

    Barjat, Hervé; Morris, Gareth A.; Swanson, Alistair G.

    1998-03-01

    A three-dimensional experiment is described in which NMR signals are separated according to their proton chemical shift,13C chemical shift, and diffusion coefficient. The sequence is built up from a stimulated echo sequence with bipolar field gradient pulses and a conventional decoupled HMQC sequence. Results are presented for a model mixture of quinine, camphene, and geraniol in deuteriomethanol.

  20. Recording 13C-15N HMQC 2D sparse spectra in solids in 30 s

    NASA Astrophysics Data System (ADS)

    Kupče, Ēriks; Trébosc, Julien; Perrone, Barbara; Lafon, Olivier; Amoureux, Jean-Paul

    2018-03-01

    We propose a dipolar HMQC Hadamard-encoded (D-HMQC-Hn) experiment for fast 2D correlations of abundant nuclei in solids. The main limitation of the Hadamard methods resides in the length of the encoding pulses, which results from a compromise between the selectivity and the sensitivity due to losses. For this reason, these methods should mainly be used with sparse spectra, and they profit from the increased separation of the resonances at high magnetic fields. In the case of the D-HMQC-Hn experiments, we give a simple rule that allows directly setting the optimum length of the selective pulses, versus the minimum separation of the resonances in the indirect dimension. The demonstration has been performed on a fully 13C,15N labelled f-MLF sample, and it allowed recording the build-up curves of the 13C-15N cross-peaks within 10 min. However, the method could also be used in the case of less sensitive samples, but with more accumulations.

  1. The EDDA experiment at COSY

    NASA Astrophysics Data System (ADS)

    Rohdjess, H.

    1998-01-01

    Polarized and unpolarized proton-proton elastic scattering is investigated with the EDDA-experiment at the Cooler Synchrotron COSY at Jülich to significantly improve the world data base in the beam energy range 500-2500 MeV. Measurements during beam acceleration with thin internal targets and a large acceptance detector produce excitation functions over a broad angular and energy range with unprecedented internal consistency. Data taking with an unpolarized CH2 fiber target and an unpolarized beam have been completed and the derived differential cross sections demonstrate the benefit of this technique. With a polarized atomic beam target recently installed in COSY and a polarized COSY beam—currently under development—the measurements will be extended to analyzing powers and spin correlation parameters.

  2. Studies on the chemical constituents of the fruits of Cordia latifolia.

    PubMed

    Siddiqui, Bina S; Perwaiz, Sobiya; Begum, Sabira

    2006-02-01

    Four new aromatic compounds have been isolated from the fruits of Cordia latifolia (Boreginaceae) bearing a common basic skeleton but differing in the side chain. Their structures were elucidated using spectrometric methods including 1D- (1H and 13C) and 2D-NMR experiments, (1H, 1H-COSY, NOESY, HMQC and HMBC) and chemical transformations.

  3. Physics at COSY-Juelich

    SciTech Connect

    Stroeher, Hans

    2011-10-21

    COSY, a storage and cooler synchrotron, which is fed by an injector cyclotron, is operated at Forschungszentrum Juelich (Germany). It provides phase space cooled polarized or unpolarized beams of protons and deuterons with momenta between 0.3 and 3.7 GeV/c for internal experiments and to external target stations. The major experimental facilities, used for the ongoing physics program, are ANKE and WASA (internal) and TOF (external). A new internal target station to investigate polarization build-up by spin-filtering (PAX) has recently been commissioned. COSY is the machine for hadron spin physics on a world-wide scale, which is also used for tests inmore » conjunction with plans to build a dedicated storage ring for electric dipole moment (EDM) measurements of proton, deuteron and {sup 3}He. In this contribution recent results as well as future plans are summarized.« less

  4. Spin-filtering at COSY

    NASA Astrophysics Data System (ADS)

    Weidemann, Christian; PAX Collaboration

    2011-05-01

    The Spin Filtering experiments at COSY and AD at CERN within the framework of the Polarized Antiproton EXperiments (PAX) are proposed to determine the spin-dependent cross sections in bar pp scattering by observation of the buildup of polarization of an initially unpolarized stored antiproton beam after multiple passage through an internal polarized gas target. In order to commission the experimental setup for the AD and to understand the relevant machine parameters spin-filtering will first be done with protons at COSY. A first major step toward this goal has been achieved with the installation of the required mini-β section in summer 2009 and it's commissioning in January 2010. The target chamber together with the atomic beam source and the so-called Breit-Rabi polarimeter have been installed and commissioned in summer 2010. In addition an openable storage cell has been used. It provides a target thickness of 5·1013 atoms/cm2. We report on the status of spin-filtering experiments at COSY and the outcome of a recent beam time including studies on beam lifetime limitations like intra-beam scattering and the electron-cooling performance as well as machine acceptance studies.

  5. Recent Results from Experiments at COSY

    SciTech Connect

    Goldenbaum, Frank

    2010-08-05

    In hadron physics, experiments using hadronic probes may shed light on open questions on the structure of hadrons, their interactions that are subject to the strong force and on the symmetries of nature. Therefore a major focus of the physics program studied at the COoler SYnchrotron COSY of the Forschungszentrum Juelich is the production of mesons and hyperons in hadron- hadron scattering with the aim to investigate relevant production processes, interactions of the participating particles as well as symmetries and symmetry breaking. The COoler SYnchrotron COSY at Juelich accelerates protons and deuterons with momenta up to 3.7 GeV/c covering hadronmore » physics in the light quark sector. The availability of the beam cooling systems allow precision measurements, using polarized proton and deuteron beams in combination with polarized Hydrogen or Deuterium targets. Due to the excellent experimental conditions at COSY single- and double-polarization measurements can be performed with high reaction rates. With the operation of the recently installed WASA-at-COSY apparatus, high-statistics studies aiming at rare decays of {eta} and {eta}{sup '} are effectively turning COSY into a meson factory. This contribution summarizes the ongoing physics program at the COSY facility, using the detector systems ANKE, WASA and COSY-TOF highlighting a few selective recent results and outlining future developments. The research at COSY also provides a step towards the realization of FAIR with studies on spin manipulation and polarization build-up of protons in polarized targets.« less

  6. Complete (1)H resonance assignment of beta-maltose from (1)H-(1)H DQ-SQ CRAMPS and (1)H (DQ-DUMBO)-(13)C SQ refocused INEPT 2D solid-state NMR spectra and first principles GIPAW calculations.

    PubMed

    Webber, Amy L; Elena, Bénédicte; Griffin, John M; Yates, Jonathan R; Pham, Tran N; Mauri, Francesco; Pickard, Chris J; Gil, Ana M; Stein, Robin; Lesage, Anne; Emsley, Lyndon; Brown, Steven P

    2010-07-14

    A disaccharide is a challenging case for high-resolution (1)H solid-state NMR because of the 24 distinct protons (14 aliphatic and 10 OH) having (1)H chemical shifts that all fall within a narrow range of approximately 3 to 7 ppm. High-resolution (1)H (500 MHz) double-quantum (DQ) combined rotation and multiple pulse sequence (CRAMPS) solid-state NMR spectra of beta-maltose monohydrate are presented. (1)H-(1)H DQ-SQ CRAMPS spectra are presented together with (1)H (DQ)-(13)C correlation spectra obtained with a new pulse sequence that correlates a high-resolution (1)H DQ dimension with a (13)C single quantum (SQ) dimension using the refocused INEPT pulse-sequence element to transfer magnetization via one-bond (13)C-(1)H J couplings. Compared to the observation of only a single broad peak in a (1)H DQ spectrum recorded at 30 kHz magic-angle spinning (MAS), the use of DUMBO (1)H homonuclear decoupling in the (1)H DQ CRAMPS experiment allows the resolution of distinct DQ correlation peaks which, in combination with first-principles chemical shift calculations based on the GIPAW (Gauge Including Projector Augmented Waves) plane-wave pseudopotential approach, enables the assignment of the (1)H resonances to the 24 distinct protons. We believe this to be the first experimental solid-state NMR determination of the hydroxyl OH (1)H chemical shifts for a simple sugar. Variable-temperature (1)H-(1)H DQ CRAMPS spectra reveal small increases in the (1)H chemical shifts of the OH resonances upon decreasing the temperature from 348 K to 248 K.

  7. Physics with WASA-at-COSY

    SciTech Connect

    Schadmand, Susan

    2010-12-28

    The WASA detector facility is an internal experiment at the COoler SYnchrotron COSY in Juelich, Germany. The COSY accelerator provides proton and deuteron beams with momenta up to 3.7 GeV/c giving access to hadron physics including the strange quark sector. The WASA-at-COSY physics program focuses on light meson decays where rare decays are used to scrutinize symmetries and symmetry breaking. The structure of hadrons is probed with transition form factors and hadron spectroscopy while hadron dynamics is studied via reaction dynamics and few body reactions. Goals and status are reported with special emphasis on the meson Dalitz decays.

  8. Probing hydrogen bonding in cocrystals and amorphous dispersions using (14)N-(1)H HMQC solid-state NMR.

    PubMed

    Tatton, Andrew S; Pham, Tran N; Vogt, Frederick G; Iuga, Dinu; Edwards, Andrew J; Brown, Steven P

    2013-03-04

    Cocrystals and amorphous solid dispersions have generated interest in the pharmaceutical industry as an alternative to more established solid delivery forms. The identification of intermolecular hydrogen bonding interactions in a nicotinamide palmitic acid cocrystal and a 50% w/w acetaminophen-polyvinylpyrrolidone solid dispersion are reported using advanced solid-state magic-angle spinning (MAS) NMR methods. The application of a novel (14)N-(1)H HMQC experiment, where coherence transfer is achieved via through-space couplings, is shown to identify specific hydrogen bonding motifs. Additionally, (1)H isotropic chemical shifts and (14)N electric field gradient (EFG) parameters, both accessible from (14)N-(1)H HMQC experiments, are shown to be sensitive to changes in hydrogen bonding geometry. Numerous indicators of molecular association are accessible from this experiment, including NH cross-peaks occurring from intermolecular hydrogen bonds and changes in proton chemical shifts or electric field gradient parameters. First-principles calculations using the GIPAW approach that yield accurate estimates of isotropic chemical shifts, and EFG parameters were used to assist in assignment. It is envisaged that (14)N-(1)H HMQC solid state NMR experiments could become a valuable screening technique of solid delivery forms in the pharmaceutical industry.

  9. Recent results from WASA-at-COSY

    SciTech Connect

    Hejny, V.

    2010-12-28

    WASA--a 4{pi} spectrometer for detection of charged and neutral particles--started operation at the cooler synchrotron COSY-Juelich in 2007. A number of experiments on meson production and decays have been carried out since then. The status of the analysis and preliminary results of some selected topics from the physics program are discussed.

  10. Electrostatic potential map modelling with COSY Infinity

    NASA Astrophysics Data System (ADS)

    Maloney, J. A.; Baartman, R.; Planche, T.; Saminathan, S.

    2016-06-01

    COSY Infinity (Makino and Berz, 2005) is a differential-algebra based simulation code which allows accurate calculation of transfer maps to arbitrary order. COSY's existing internal procedures were modified to allow electrostatic elements to be specified using an array of field potential data from the midplane. Additionally, a new procedure was created allowing electrostatic elements and their fringe fields to be specified by an analytic function. This allows greater flexibility in accurately modelling electrostatic elements and their fringe fields. Applied examples of these new procedures are presented including the modelling of a shunted electrostatic multipole designed with OPERA, a spherical electrostatic bender, and the effects of different shaped apertures in an electrostatic beam line.

  11. Status of the EDDA experiment at COSY

    NASA Astrophysics Data System (ADS)

    Scobel, W.; EDDA Collaboration; Bisplinghoff, J.; Bollmann, R.; Cloth, P.; Dohrmann, F.; Dorner, G.; Drüke, V.; Ernst, J.; Eversheim, P. D.; Filges, D.; Gasthuber, M.; Gebel, R.; Groß, A.; Groß-Hardt, R.; Hinterberger, F.; Jahn, R.; Lahr, U.; Langkau, R.; Lippert, G.; Mayer-Kuckuk, T.; Maschuw, R.; Mertler, G.; Metsch, B.; Mosel, F.; Paetz gen Schieck, H.; Petry, H. R.; Prasuhn, D.; von Przewoski, B.; Rohdjeß, H.; Rosendaal, D.; von Rossen, P.; Scheid, H.; Schirm, N.; Schwandt, F.; Stein, H.; Theis, D.; Weber, J.; Wiedmann, W.; Woller, K.; Ziegler, R.

    1993-07-01

    The EDDA experiment is designed to study p + p excitation functions with high energy resolution and narrow step size in the kinetic energy range from 250 MeV to 2500 MeV at the Cooler Synchrotron COSY. Measurements during the accelertion phase in conjunction with internal targets will allow to achieve a fast and precise energy variation. Prototypes of the detector elements and the fiber target have been extensively tested with proton and electron beams; the detector performance and trigger efficiency have been studied in Monte Carlo simulations. In this contribution, results concerning detector design, prototype studies, Monte Carlo simulations and the anticipated detector resolutions will be reported.

  12. Spin Filtering Studies at COSY and AD

    SciTech Connect

    Nass, Alexander

    2009-08-04

    The high physics potential of experiments with stored high-energy polarized antiprotons led to the proposal of PAX (Polarized Antiproton eXperiment) for the High Energy Storage Ring (HESR) of the FAIR at GSI (Darmstadt/Germany). It is proposed to polarize a stored antiproton beam by means of spin filtering with a polarized H (D) gas target. The feasibility of spin filtering has been demonstrated in the FILTEX experiment. The current interpretation foresees a self-cancellation of the electron contribution to the filtering process and only the hadronic contribution is effective. Several experimental studies with protons (at COSY/Juelich) as well as antiprotons (at AD/CERN)more » will be carried out to test the principle and measure p-barp-vector and p-bard-vector cross sections. A polarized internal gas target (PIT) with surrounding Silicon detectors immersed into a low-beta section has to be set up.« less

  13. Spin Filtering Studies at COSY and AD

    NASA Astrophysics Data System (ADS)

    Nass, Alexander

    2009-08-01

    The high physics potential of experiments with stored high-energy polarized antiprotons led to the proposal of PAX (Polarized Antiproton eXperiment) [1] for the High Energy Storage Ring (HESR) of the FAIR at GSI (Darmstadt/Germany). It is proposed to polarize a stored antiproton beam by means of spin filtering with a polarized H (D) gas target. The feasibility of spin filtering has been demonstrated in the FILTEX experiment. The current interpretation foresees a self-cancellation of the electron contribution to the filtering process and only the hadronic contribution is effective. Several experimental studies with protons (at COSY/Jülich) as well as antiprotons (at AD/CERN) will be carried out to test the principle and measure p¯p⃗ and p¯d⃗ cross sections. A polarized internal gas target (PIT) with surrounding Silicon detectors immersed into a low-β section has to be set up.

  14. The Polarized Deuteron Breakup Experiment at COSY

    NASA Astrophysics Data System (ADS)

    Rathmann, F.; Barsov, S.; Dymov, S.; Kacharava, A.; Khoukaz, A.; Komarov, V.; Kulikov, A.; Kurbatov, A.; Lang, N.; Lehmann, I.; Lorentz, B.; Macharashvili, G.; Mussgiller, A.; Paetz gen. Schieck, H.; Schleichert, R.; Seyfarth, H.; Steffens, E.; Ströher, H.; Uzikov, Yu.; Yaschenko, S.; Zalikhanov, B.

    2003-07-01

    A study of the deuteron breakup reaction pd → (pp)n with forward emission of a fast proton pair with small excitation energy Epp < 3 MeV has been performed using the ANKE spectrometer at COSY Jülich. The differential cross section of the breakup reaction, averaged up to 8° over the cm polar angle of the total momentum of the pp pairs, has been obtained at six proton beam energies Tp = 0.6, 0.7, 0.8, 0.95, 1.35, and 1.9 GeV. A first measurement of the vector analyzing power Ayp has been carried out, using a polarization normalization obtained with the EDDA detector. In addition, for the first time asymmetries of p⃗d elastic scattering at Tp = 500 MeV have been recorded with the spectator setup at ANKE.

  15. Spin-Flipping Polarized Deuterons At COSY

    NASA Astrophysics Data System (ADS)

    Yonehara, K.; Krisch, A. D.; Morozov, V. S.; Raymond, R. S.; Wong, V. K.; Bechstedt, U.; Gebel, R.; Lehrach, A.; Lorenz, B.; Maier, R.; Prasuhn, D.; Schnase, A.; Stockhorst, H.; Eversheim, D.; Hinterberger, F.; Rohdjess, H.; Ulbrich, K.; Scobel, W.

    2004-02-01

    We recently stored a 1.85 GeV/c vertically polarized deuteron beam in the COSY Ring in Jülich; we then spin-flipped it by ramping a new air-core rf dipole's frequency through an rf-induced spin resonance to manipulate the polarization direction of the deuteron beam. We first experimentally determined the resonance's frequency and set the dipole's rf voltage to its maximum; then we varied its frequency ramp time and frequency range. We used the EDDA detector to measure the vector and tensor polarization asymmetries. We have not yet extracted the deuteron's tensor polarization spin-flip parameters from the measured data, since our short run did not provide adequate tensor analyzing-power data at 1.85 GeV/c. However, with a 100 Hz frequency ramp and our longest ramp time of 400 s, the deuterons' vector polarization spin-flip efficiency was 48±1%.

  16. CLIP-COSY: A Clean In-Phase Experiment for the Rapid Acquisition of COSY-type Correlations.

    PubMed

    Koos, Martin R M; Kummerlöwe, Grit; Kaltschnee, Lukas; Thiele, Christina M; Luy, Burkhard

    2016-06-27

    The COSY experiment is an essential homonuclear 2D NMR experiment for the assignment of resonances. Its multiplet line shape, however, is often overly complicated, potentially leads to signal intensity losses, and is responsible for long minimum overall acquisition times. Herein, we present CLIP-COSY, a COSY-type experiment yielding clean in-phase peaks. It can be recorded within a few minutes and benefits from enhanced signal intensities for most cross-peaks. In combination with non-uniform sampling, the experiment times can be further reduced, and the in-phase multiplets enable the application of modern homonuclear decoupling techniques in both dimensions. As antiphase cancelations are avoided, CLIP-COSY can also be applied to macromolecules and other samples with broadened lines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. The Proposed 2 MeV Electron Cooler for COSY

    SciTech Connect

    Dietrich, Juergen; Parkhomchuk, Vasily V.; Reva, Vladimir B.

    2006-03-20

    The design, construction and installation of a 2 MeV electron cooling system for COSY is proposed to further boost the luminosity even with strong heating effects of high-density internal targets. In addition the design of the 2 MeV electron cooler for COSY is intended to test some new features of the high energy electron cooler for HESR at GSI. The design of the 2 MeV electron cooler will be accomplished in cooperation with the Budker Institute of Nuclear Physics in Novosibirsk, Russia. Starting with the boundary conditions of the existing electron cooler at COSY the requirements and a first generalmore » scheme of the 2 MeV electron cooler are described.« less

  18. Band structure and unconventional electronic topology of CoSi

    NASA Astrophysics Data System (ADS)

    Pshenay-Severin, D. A.; Ivanov, Y. V.; Burkov, A. A.; Burkov, A. T.

    2018-04-01

    Semimetals with certain crystal symmetries may possess unusual electronic structure topology, distinct from that of the conventional Weyl and Dirac semimetals. Characteristic property of these materials is the existence of band-touching points with multiple (higher than two-fold) degeneracy and nonzero Chern number. CoSi is a representative of this group of materials exhibiting the so-called ‘new fermions’. We report on an ab initio calculation of the electronic structure of CoSi using density functional methods, taking into account the spin-orbit interactions. The linearized \

  19. EPIC Muon Cooling Simulations using COSY INFINITY

    SciTech Connect

    J.A. Maloney, B. Erdelyi, A. Afanasev, R.P. Johnson, S.A. Bogacz, Y.S. Derbenev, V.S. Morozov

    2011-03-01

    Next gen­er­a­tion mag­net sys­tems need­ed for cool­ing chan­nels in both neu­tri­no fac­to­ries and muon col­lid­ers will be in­no­va­tive and com­pli­cat­ed. De­sign­ing, sim­u­lat­ing and op­ti­miz­ing these sys­tems is a chal­lenge. Using COSY IN­FIN­I­TY, a dif­fer­en­tial al­ge­bra-based code, to sim­u­late com­pli­cat­ed el­e­ments can allow the com­pu­ta­tion and cor­rec­tion of a va­ri­ety of high­er order ef­fects, such as spher­i­cal and chro­mat­ic aber­ra­tions, that are dif­fi­cult to ad­dress with other sim­u­la­tion tools. As an ex­am­ple, a he­li­cal dipole mag­net has been im­ple­ment­ed and sim­u­lat­ed, and the per­for­mance of an epicyclic para­met­ric ion­iza­tion cool­ing sys­tem for muons is stud­ied and com­pared to sim­u­la­tions made usingmore » G4Beam­line, a GEAN­T4 toolk­it.« less

  20. Meson Production and Decays with WASA at COSY

    SciTech Connect

    Schadmand, Susan

    2011-10-21

    The WASA-at-COSY physics program focuses on light meson decays where rare decays are used to scrutinize symmetries and symmetry breaking. The structure of hadrons is probed with transition form factors and hadron spectroscopy while hadron dynamics is studied via reaction dynamics and few body reactions.

  1. COSIE: The Coronal Spectrographic Imager in the EUV

    NASA Technical Reports Server (NTRS)

    Savage, Sabrina; Golub, Leon; Deluca, Ed

    2017-01-01

    COSIE is a solar-observing instrument (currently proposed for mounting onto the ISS) which obtains wide field images of the corona and full Sun spectral images with high sensitivity and rapid cadence. The primary purpose of the instrument is to constrain the global field topology and to track coronal mass ejections from the disk through the inner heliosphere.

  2. Teucrium polium phenylethanol and iridoid glycoside characterization and flavonoid inhibition of biofilm-forming Staphylococcus aureus.

    PubMed

    Elmasri, Wael A; Yang, Tianjiao; Tran, Phat; Hegazy, Mohamed-Elamir F; Hamood, Abdul N; Mechref, Yehia; Paré, Paul W

    2015-01-23

    The chemical composition and biofilm regulation of 15 metabolites from Teucrium polium are reported. Compounds were isolated from a CH2Cl2-MeOH extract of the aerial parts of the plant and included iridoid and phenylethanol glycosides and a monoterpenoid, together with nine known compounds. The structures were elucidated based on standard spectroscopic (UV, (1)H and (13)C NMR), 2D NMR ((1)H-(1)H COSY, HMQC, HMBC, and NOESY), and/or LC-ESIMS/MS data analyses. Inhibition of the biofilm-forming strain Staphylococcus aureus was observed with exposure to compounds 7 and 8.

  3. Physics Program at COSY-Juelich with Polarized Hadronic Probes

    SciTech Connect

    Kacharava, Andro

    2009-08-04

    Hadron physics aims at a fundamental understanding of all particles and their interactions that are subject to the strong force. Experiments using hadronic probes could contribute to shed light on open questions on the structure of hadrons and their interaction as well as the symmetries of nature. The COoler SYnchrotron COSY at the Forschungszentrum Juelich accelerates protons and deuterons with momenta up to 3.7 GeV/c. The availability of both an electron cooler as well as a stochastic beam cooling system allows for precision measurements, using polarized proton and deuteron beams in combination with polarized Hydrogen or Deuterium targets.This contribution summarizesmore » the ongoing physics program at the COSY facility using ANKE, WASA and TOF detector systems with polarized hadronic probes, highlighting recent results and outlining the new developments.« less

  4. Recent Results from the WASA-at-COSY Experiment

    SciTech Connect

    Kupsc, Andrzej

    2011-10-24

    Studies of light meson decays are the key experiments for the WASA detector at COSY-Juelich. One of the world largest data samples of the {eta} meson decays have been recently collected in the pd {yields}{sup 3}He{eta} and in the pp {yields} pp{eta} reactions. The status of the analysis of various decay channels and the further plans for the light meson decay program are presented.

  5. Status and future plans of polarized beams at COSY

    NASA Astrophysics Data System (ADS)

    Lorentz, B.; Gebel, R.; Lehrach, A.; Maier, R.; Prasuhn, D.; Stockhorst, H.

    2011-05-01

    In this paper we report on the present status and future plans of polarized beams in the COSY synchrotron ring. COSY is a synchrotron ring in the momentum range from 295 to 3700 MeV/c. Polarized deuterons and protons are routinely delivered to experiments over the whole momentum range. No depolarization occurs during the acceleration of deuterons in COSY. For polarized protons many depolarizing resonances are crossed without polarization loss. At imperfection resonances, vertical steerer magnets are used to increase the resonance strength, leading to a complete polarization reversal. At intrinsic resonances a fast tune jump quadrupole is used to quickly cross the resonances without loss of polarization. Typical proton polarizations are close to 0.8 below 2.1 GeV/c and about 0.6 for higher momenta. During recent operation an induced depolarizing resonance was used for accurate determination of the relative momentum spread dp/p of the stored beam yielding an accuracy of better than 10-4. For spin filter studies of the PAX collaboration a low beta target section was installed in 2009 and was successfully put into operation early 2010. An upgrade of the EDDA polarimeter electronics and data acquisition system is underway to ensure continued availability of the polarimeter, which is essential for the polarized proton operation of COSY. In the near future it is planned to install a Siberian snake solenoid of 4.5 Tm to be able to provide in addition to vertically polarized protons, longitudinal polarization as well. This solenoid will allow the preparation of a longitudinally polarized beam up to a kinetic energy of 500 MeV.

  6. First internal and external experiments at COSY Juelich

    NASA Astrophysics Data System (ADS)

    Prasuhn, D.; Maier, R.; Bechstedt, U.; Dietrich, J.; Hacker, U.; Martin, S.; Stockhorst, H.; Tölle, R.; Grzonka, D.; Nake, C.; Mosel, F.

    1995-02-01

    The inauguration of the cooler synchrotron COSY Jülich was celebrated on April 1st, 1993. After the first successful acceleration to proton momenta above 800 GeV/ c, beamtimes for experiments were scheduled in parallel to further machine development. The first experiment was the internal target experiment EDDA, which investigated the energy dependence of the p-p interaction. It makes use of a 3 × 4 μm 2 thin CH 2 fiber as an internal target. The thickness of the fiber is more than adequate to achieve high luminosities, so the intensity of the stored beam has to be reduced to 10 7 p. On the other hand, it is thin enough to achieve beam lifetimes of 3 s at 1.4 GeV/ c. Details of the target fabrication and the first experimental results will be discussed. Both external experimental facilities at COSY, the time-of-flight spectrometer, and the magnetic spectrometer BIG KARL use a liquid hydrogen (deuterium) target. The first experiments were carried out at proton energies between 300 MeV and 500 MeV. Also, these experimental data will be presented. Two further internal experiments are prepared for the installation into the COSY ring. The target for the first experiment is a gas-jet target, the second experiment uses ribbon targets for the interaction. The status of both experimental setups will be shown.

  7. Earth Surface Monitoring with COSI-Corr, Techniques and Applications

    NASA Astrophysics Data System (ADS)

    Leprince, S.; Ayoub, F.; Avouac, J.

    2009-12-01

    Co-registration of Optically Sensed Images and Correlation (COSI-Corr) is a software package developed at the California Institute of Technology (USA) for accurate geometrical processing of optical satellite and aerial imagery. Initially developed for the measurement of co-seismic ground deformation using optical imagery, COSI-Corr is now used for a wide range of applications in Earth Sciences, which take advantage of the software capability to co-register, with very high accuracy, images taken from different sensors and acquired at different times. As long as a sensor is supported in COSI-Corr, all images between the supported sensors can be accurately orthorectified and co-registered. For example, it is possible to co-register a series of SPOT images, a series of aerial photographs, as well as to register a series of aerial photographs with a series of SPOT images, etc... Currently supported sensors include the SPOT 1-5, Quickbird, Worldview 1 and Formosat 2 satellites, the ASTER instrument, and frame camera acquisitions from e.g., aerial survey or declassified satellite imagery. Potential applications include accurate change detection between multi-temporal and multi-spectral images, and the calibration of pushbroom cameras. In particular, COSI-Corr provides a powerful correlation tool, which allows for accurate estimation of surface displacement. The accuracy depends on many factors (e.g., cloud, snow, and vegetation cover, shadows, temporal changes in general, steadiness of the imaging platform, defects of the imaging system, etc...) but in practice, the standard deviation of the measurements obtained from the correlation of mutli-temporal images is typically around 1/20 to 1/10 of the pixel size. The software package also includes post-processing tools such as denoising, destriping, and stacking tools to facilitate data interpretation. Examples drawn from current research in, e.g., seismotectonics, glaciology, and geomorphology will be presented. COSI-Corr is

  8. New cycloartane-type triterpenes from Marcetia latifolia (Melastomataceae) and in silico studies on Candida parapsilosis protease.

    PubMed

    Leite, Tonny C C; Leite, Franco H A; Vieira, Ivo J C; Braz Filho, Raimundo; Branco, Alexsandro

    2013-08-01

    We have previously reported the antimicrobial activity of the ethyl acetate extract of Marcetia latifolia, particularly against Candida parapsilosis. In this work we describe the isolation of two new cycloartane-type triterpenes, 28,29-bis-norcycloartan-3beta,4alpha-diol (1) and 28,29-bis-norcycloart-24-en-3beta,4alpha-diol (2) from the same extract. These compounds were mainly characterized by one- (1H, 13C and APT) and two-dimensional (1H-1H-COSY, 1H-1H-NOESY, HMQC and HMBC) NMR spectroscopy, mass spectrometry and comparison with published structural data. In addition, the activity of triterpenes 1 and 2 on the Candida protease target was investigated by in silico methods using molecular docking.

  9. Fabrication of nanometer single crystal metallic CoSi2 structures on Si

    NASA Technical Reports Server (NTRS)

    Nieh, Kai-Wei (Inventor); Lin, True-Lon (Inventor); Fathauer, Robert W. (Inventor)

    1991-01-01

    Amorphous Co:Si (1:2 ratio) films are electron gun-evaporated on clean Si(111), such as in a molecular beam epitaxy system. These layers are then crystallized selectively with a focused electron beam to form very small crystalline Co/Si2 regions in an amorphous matrix. Finally, the amorphous regions are etched away selectively using plasma or chemical techniques.

  10. Neutral decays of {eta}{sup '} at WASA-at-COSY

    SciTech Connect

    Duniec, David; Jany, Benedykt R.; IKP-2 Forschungszentrum Juelich, 52428 Juelich

    2007-11-07

    The status and some of the goals of the {eta}{sup '} physics program at WASA-at-COSY with regards to neutral hadronic decays are presented. Very preliminary results of a test run from WASA-at-COSY in May 2007 are presented.

  11. pp Elastic Scattering: New results from EDDA (COSY)

    NASA Astrophysics Data System (ADS)

    Scobel, W.

    2000-06-01

    In the EDDA experiment excitation functions of proton-proton elastic scattering are studied with narrow steps in the projectile momentum range from 0.8 to 3.4 GeV/c and the angular range 35°⩽Θcm⩽90° with a detector providing ΔΘcm≈1.4° resolution and 85% solid angle coverage. Measurements are performed continuously during projectile acceleration in the Cooler Synchrotron COSY. In phase 1 of the experiment spin-averaged differential cross sections dσ/dΩ have been measured with an internal CH2 fiber target; background corrections were derived from measurements with a carbon fiber target and from Monte Carlo simulations of inelastic pp contributions. The results provide excitation functions and angular distributions of high precision and internal consistency. In phase 2 of the experiment excitation functions of the analyzing power AN have been measured using a polarized (P⩾75%) atomic beam target, and those of the polarization correlation parameters ANN, ASS and ASL will be measured lateron with the polarized COSY beam. The measured excitation functions are compared to recent phase shift analyses, and their impact on them is discussed. So far evidence for narrow structures was neither found in the spin averaged cross sections nor in the analyzing powers.

  12. Test of Time-Reversal Invariance at COSY (TRIC)

    NASA Astrophysics Data System (ADS)

    Eversheim, D.; Valdau, Yu.; Lorentz, B.

    2016-02-01

    At the Cooler Synchrotron COSY a novel (P-even, T-odd) null test of time-reversal invariance to an accuracy of 10-6 is planned as an internal target transmission experiment. The parity conserving time-reversal violating observable is the total cross-section asymmetry Ay,xz. This quantity is measured using a polarized proton beam with an energy of 135 MeV and an internal tensor polarized deuteron target from the PAX atomic beam source. The reaction rate will be determined by the lifetime of the beam. Consequently, the accuracy of the current measurement of the circulating proton beam is crucial for this experiment. Thus, the cooler synchroton ring serves as an ideal forward spectrometer, as a detector, and an accelerator.

  13. Test of time-reversal invariance at COSY (TRIC)

    NASA Astrophysics Data System (ADS)

    Eversheim, D.; Valdau, Yu.; Lorentz, B.

    2013-03-01

    At the Cooler Synchrotron COSY a novel (P-even, T-odd) null test of time-reversal invariance to an accuracy of 10 - 6 is planned as an internal target transmission experiment. The parity conserving time-reversal violating observable is the total cross-section asymmetry Ay,xz. This quantity is measured using a polarized proton beam with an energy of 135 MeV and an internal tensor polarized deuteron target from the PAX atomic beam source. The reaction rate will be measured by means of an integrating beam current transformer. Thus, in this experiment the cooler synchroton ring serves as ideal forward spectrometer, as a detector, and an accelerator.

  14. Spin Manipulating Vector and Tensor Polarized Deuterons Stored in COSY

    NASA Astrophysics Data System (ADS)

    Morozov, Vassili; Krisch, Alan; Leonova, Maria; Raymond, Richard; Sivers, Dennis; Wong, Victor; Yonehara, Katsuya; Bechstedt, Ulf; Gebel, Ralf; Lehrach, Andreas; Lorentz, Bernd; Maier, Rudolf; Schnase, Alexander; Stockhorst, Hans; Eversheim, Dieter; Hinterberger, Frank; Rohdjess, Heiko; Ulbrich, Kay

    2004-05-01

    We recently studied spin flipping and spin manipulation of a simultaneously vector and tensor polarized deuteron beam stored in the COSY Cooler Synchrotron at 1.85 GeV/c. Using the EDDA detector we calibrated vector and tensor analyzing powers, which were earlier unknown at this energy; thus, we were able to obtain the absolute values for both the vector and tensor polarizations. We manipulated the deuteron's polarization using a new water-cooled ferrite rf dipole, by adiabatically sweeping its frequency through an rf-induced spin resonance. We first experimentally determined the resonance's frequency and then varied the dipole's frequency range and frequency ramp time. This allowed us to maximize the vector polarization spin-flip efficiency to about 97 ± 1%. We also studied the interesting tensor polarization manipulation in considerable detail.

  15. Study of light mesons with WASA-at-COSY

    NASA Astrophysics Data System (ADS)

    Prencipe, Elisabetta

    2014-06-01

    The WASA detector, operating at the COSY facility in Jülich (Germany) has been collecting data since 2007. The experiment allows to perform studies of light mesons, such as π0, η and ω rare decay processes, in order to perform precise measurements of branching ratios, determine Dalitz plot parameters, test symmetry and symmetry breaking, and evaluate transition form factors. In the experiments a proton or deuteron beam impinged on a pellet target of hydrogen or deuterium, which allows the reactions proton-proton (pp) or proton-deuteron (pd). A high-statistics sample of η mesons has been collected: in the reaction pd →3He η, 3×107η mesons were tagged at a beam energy of 1.0 GeV, while 5×108η mesons were produced in the reaction pp → ppη at 1.4 GeV. This corresponds to the production of 10 η/s and 100 η/s, respectively, for the two reaction processes. In the pp dataset a higher background level is found compared to the pd data set. In both cases, we identify the η mesons by means of the missing mass derived from the recoil particles. A kinematic fit largely rejects the background in our analysis. The advantage in using the pp dataset is that the production of η mesons is almost a factor of 10 higher than in the pd fusion to 3He. As we plan to measure the branching ratios of very rare processes, high statistics is needed. A summary of the recent activity on the study of light mesons with WASA-at-COSY here is given.

  16. Subsurface Growth of CoSi2 by Deposition of Co on Si-Capped CoSi2 Seed Regions

    NASA Technical Reports Server (NTRS)

    Fathauer, R. W.; George, T.; Pike, W. T.

    1991-01-01

    At a growth temperature of 800 C, Co deposited on Si(111) diffuses through a Si cap and exhibits oriented growth on buried CoSi2 grains, a process referred to as endotaxy. This occurs preferentially to surface nucleation of CoSi2 provided the thickness of the Si cap is less than a critical value between 100 and 200 nm for a deposition rate of 0.01 nm/s. Steady-state endotaxy is modeled under the assumption that the process is controlled by Co diffusion.

  17. Interfacial stability of CoSi2/Si structures grown by molecular beam epitaxy

    NASA Technical Reports Server (NTRS)

    George, T.; Fathauer, R. W.

    1992-01-01

    The stability of CoSi2/Si interfaces was examined in this study using columnar silicide structures grown on (111) Si substrates. In the first set of experiments, Co and Si were codeposited using MBE at 800 C and the resulting columnar silicide layer was capped by epitaxial Si. Deposition of Co on the surface of the Si capping layer at 800 C results in the growth of the buried silicide columns. The buried columns grow by subsurface diffusion of the deposited Co, suppressing the formation of surface islands of CoSi2. The column sidewalls appear to be less stable than the top and bottom interfaces, resulting in preferential lateral growth and ultimately in the coalescence of the columns to form a continuous buried CoSi2 layer. In the second set of experiments, annealing of a 250 nm-thick buried columnar layer at 1000 C under a 100 nm-thick Si capping layer results in the formation of a surface layer of CoSi2 with a reduction in the sizes of the CoSi2 columns. For a sample having a thicker Si capping layer the annealing leads to Ostwald ripening producing buried equiaxed columns. The high CoSi2/Si interfacial strain could provide the driving force for the observed behavior of the buried columns under high-temperature annealing.

  18. Determination of long-range scalar (1)H-(1)H coupling constants responsible for polarization transfer in SABRE.

    PubMed

    Eshuis, Nan; Aspers, Ruud L E G; van Weerdenburg, Bram J A; Feiters, Martin C; Rutjes, Floris P J T; Wijmenga, Sybren S; Tessari, Marco

    2016-04-01

    SABRE (Signal Amplification By Reversible Exchange) nuclear spin hyperpolarization method can provide strongly enhanced NMR signals as a result of the reversible association of small molecules with para-hydrogen (p-H2) at an iridium metal complex. The conversion of p-H2 singlet order to enhanced substrate proton magnetization within such complex is driven by the scalar coupling interactions between the p-H2 derived hydrides and substrate nuclear spins. In the present study these long-range homonuclear couplings are experimentally determined for several SABRE substrates using an NMR pulse sequence for coherent hyperpolarization transfer at high magnetic field. Pyridine and pyrazine derivatives appear to have a similar ∼1.2 Hz (4)J coupling to p-H2 derived hydrides for their ortho protons, and a much lower (5)J coupling for their meta protons. Interestingly, the (4)J hydride-substrate coupling for five-membered N-heterocyclic substrates is well below 1 Hz. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Determination of long-range scalar 1H-1H coupling constants responsible for polarization transfer in SABRE

    NASA Astrophysics Data System (ADS)

    Eshuis, Nan; Aspers, Ruud L. E. G.; van Weerdenburg, Bram J. A.; Feiters, Martin C.; Rutjes, Floris P. J. T.; Wijmenga, Sybren S.; Tessari, Marco

    2016-04-01

    SABRE (Signal Amplification By Reversible Exchange) nuclear spin hyperpolarization method can provide strongly enhanced NMR signals as a result of the reversible association of small molecules with para-hydrogen (p-H2) at an iridium metal complex. The conversion of p-H2 singlet order to enhanced substrate proton magnetization within such complex is driven by the scalar coupling interactions between the p-H2 derived hydrides and substrate nuclear spins. In the present study these long-range homonuclear couplings are experimentally determined for several SABRE substrates using an NMR pulse sequence for coherent hyperpolarization transfer at high magnetic field. Pyridine and pyrazine derivatives appear to have a similar ∼1.2 Hz 4J coupling to p-H2 derived hydrides for their ortho protons, and a much lower 5J coupling for their meta protons. Interestingly, the 4J hydride-substrate coupling for five-membered N-heterocyclic substrates is well below 1 Hz.

  20. SPIN-COSY: Spin-Manipulating Polarized Deuterons and Protons

    SciTech Connect

    Leonova, M. A.; Chao, A. W.; Krisch, A. D.

    2009-08-04

    We studied spin manipulation of 1.85 GeV/c polarized deuteron beam stored in COSY obtaining a spin-flip efficiency of 97{+-}1%. We first discovered experimentally and then explained theoretically interesting behavior of the deuteron tensor polarization. We, for the first time, studied systematically spin resonance strengths induced by rf dipoles and solenoids. We found huge disagreements between the strengths measured in controlled Froissart-Stora sweeps and the theoretical values calculated using the well-known formulae. These data instigated re-examination of these formulae. We tested Chao's proposed new matrix formalism for describing the spin dynamics due to a single spin resonance, which may be themore » first fundamental improvement of the Froissart-Stora equation in that it allows analytic calculation of the beam polarization's behavior inside a resonance. Our measurements of the deuteron's polarization near and inside the resonance agreed precisely with the Chao formalism's predicted oscillations. We tested Kondratenko's proposal to overcome depolarizing resonances by ramping through them with a crossing pattern, which should force the depolarizing contributions to cancel themselves. Our first test of this idea with 2.1 GeV/c protons was not conclusive but a later test with 1.85 GeV/c deuterons demonstrated a rather substantial reduction in the depolarization compared to the tune jump at the same rate.« less

  1. Neutron-Proton Scattering Experiments at ANKE-COSY

    NASA Astrophysics Data System (ADS)

    Kacharava, A.; Chiladze, D.; Chiladze, B.; Keshelashvili, I.; Lomidze, N.; Macharashvili, G.; McHedlishvili, D.; Nioradze, M.; Rathmann, F.; Ströher, H.; Wilkin, C.

    2010-04-01

    The nucleon-nucleon interaction (NN) is fundamental for the whole of nuclear physics and hence to the composition of matter as we know it. It has been demonstrated that stored, polarised beams and polarised internal targets are experimental tools of choice to probe spin effects in NN-scattering experiments. While the EDDA experiment has dramatically improved the proton-proton date base, information on spin observables in neutron-proton scattering is very incomplete above 800 MeV, resulting in large uncertainties in isoscalar n p phase shifts. Experiments at COSY, using a polarised deuteron beam or target, can lead to significant improvements in the situation through the study of quasi-free reactions on the neutron in the deuteron. Such a measurements has already been started at ANKE by using polarised deuterons on an unpolarised target to study the dp → ppn deuteron charge-exchange reaction and the full program with a polarised storage cell target just has been conducted. At low excitation energies of the final pp system, the spin observables are directly related to the spin- dependent parts of the neutron-proton charge-exchange amplitudes. Our measurement of the deuteron-proton spin correlations will allow us to determine the relative phases of these amplitudes in addition to their overall magnitudes.

  2. Spin manipulating vector & tensor polarized deuterons stored in COSY

    NASA Astrophysics Data System (ADS)

    Morozov, V. S.; Krisch, A. D.; Leonova, M. A.; Raymond, R. S.; Sivers, D. W.; Wong, V. K.; Yonehara, K.; Gebel, R.; Lehrach, A.; Lorentz, B.; Maier, R.; Prasuhn, D.; Schnase, A.; Stockhorst, H.; Eversheim, D.; Hinterberger, F.; Rohdjess, H.; Ulbrich, K.

    2006-04-01

    We recently studied the spin manipulation of a simultaneously vector and tensor polarized deuteron beam stored at 1.85 GeV/c in the COSY Cooler Synchrotron. Using the EDDA detector, we first calibrated the vector and tensor analyzing powers, which were earlier unmeasured at 1.85 GeV/c; this allowed us to measure the absolute values of both the vector and tensor polarizations. Then we manipulated the deuteron's polarization by sweeping the frequency of a ferrite rf dipole through an rf-induced spin resonance. We first experimentally determined the resonance's frequency and then varied the rf dipole's frequency sweep range δf and frequency ramp time δt to maximize the spin-flip efficiency. We then obtained a measured vector spin-flip efficiency of 98.5 ± 0.3% [1]. We also studied, in detail, the behavior of the tensor polarization during spin manipulation; these new data may allow a better understanding of the interesting quantum behavior of spin-1 bosons. This research was supported by the German BMBF Science Ministry. [1] V.S. Morozov et al., Phys. Rev. ST Accel. Beams 8, 061001 (2005).

  3. New developments and prospects on COSI, the simulation software for fuel cycle analysis

    SciTech Connect

    Eschbach, R.; Meyer, M.; Coquelet-Pascal, C.

    2013-07-01

    COSI, software developed by the Nuclear Energy Direction of the CEA, is a code simulating a pool of nuclear power plants with its associated fuel cycle facilities. This code has been designed to study various short, medium and long term options for the introduction of various types of nuclear reactors and for the use of associated nuclear materials. In the frame of the French Act for waste management, scenario studies are carried out with COSI, to compare different options of evolution of the French reactor fleet and options of partitioning and transmutation of plutonium and minor actinides. Those studies aimmore » in particular at evaluating the sustainability of Sodium cooled Fast Reactors (SFR) deployment and the possibility to transmute minor actinides. The COSI6 version is a completely renewed software released in 2006. COSI6 is now coupled with the last version of CESAR (CESAR5.3 based on JEFF3.1.1 nuclear data) allowing the calculations on irradiated fuel with 200 fission products and 100 heavy nuclides. A new release is planned in 2013, including in particular the coupling with a recommended database of reactors. An exercise of validation of COSI6, carried out on the French PWR historic nuclear fleet, has been performed. During this exercise quantities like cumulative natural uranium consumption, or cumulative depleted uranium, or UOX/MOX spent fuel storage, or stocks of reprocessed uranium, or plutonium content in fresh MOX fuel, or the annual production of high level waste, have been computed by COSI6 and compared to industrial data. The results have allowed us to validate the essential phases of the fuel cycle computation, and reinforces the credibility of the results provided by the code.« less

  4. Spin Resonances for Stored Deuteron Beams in COSY. Vector Polarization. Tracking with Spink

    SciTech Connect

    Luccio,A.; Lehrach, A.

    2008-04-01

    Results of measurements of vector and tensor polarization of a deuteron beam in the storage ring COSY have been published by the SPIN{at}COSY collaboration. In this experiment a RF Dipole was used that produced spin flip. The strength of the RFD-induced depolarizing resonance was calculated from the amount of spin flipping and the results shown in the figures of the cited paper. In this note we present the simulation of the experimental data (vector polarization) with the spin tracking code Spink.

  5. Evaluation of mechanical and transport properties of Zr2CoSi Heusler alloy

    NASA Astrophysics Data System (ADS)

    Yousuf, Saleem; Khandy, S. A.; Bhat, T. M.; Gupta, D. C.

    2017-05-01

    Systematic investigation of mechanical and transport properties of Zr2CoSi within the density functional theory have been analysed. From the elastic constants, the shear modulus, Young's modulus, Poisson's ratio, we conclude the ductile nature of alloy. Thermoelectric properties show that Zr2CoSi as an n-type thermoelectric material with a higher increase in Seebeck coefficient with temperature. Further the power factor analysis confirms the heavily doping of the alloy fruitful for increase in thermoelectric performance and its use for the future thermoelectric spin generators.

  6. Measurement of the transition form factor of {eta} meson with WASA-at-COSY

    SciTech Connect

    Bhatt, H.

    2011-10-24

    Reaction {eta}{yields}e{sup +}e{sup -}{gamma} is used to investigate the transition form factor of {eta} meson with WASA detector at COSY. Where the {eta} meson is produced in pp collision at 1.4 GeV. We present the analysis techniques and preliminary results of {eta} Dalitz decays.

  7. Computer Conferencing in Health Sciences: CoSy at McMaster

    PubMed Central

    Ahmed, K.; Ridley, M.

    1988-01-01

    Computer conferencing systems provide a novel and economical way to exchange ideas and maintain fruitful collaboration across wide distances. There is considerable potential value in using conferencing system in research, education, case discussion and administration. The early experience is encouraging. We discuss a number of ways in which CoSy is being used in Health Sciences.

  8. Cytotoxic withanolides from Physalis angulata L.

    PubMed

    He, Qing-Ping; Ma, Lei; Luo, Jie-Ying; He, Fu-Yuan; Lou, Li-Guang; Hu, Li-Hong

    2007-03-01

    Four new withanolides, physagulins L-O (1-4), were isolated from the MeOH extract of the aerial parts of Physalis angulata L. (Solanaceae), together with seven known withanolides, compounds 5-11. Their structures were determined by spectroscopic techniques, including 1H-, 13C-NMR (DEPT), and 2D-NMR (HMBC, HMQC, 1H,1H-COSY, NOESY) experiments, as well as by HR-MS. All eleven compounds were tested for their antiproliferative activities towards human colorectal-carcinoma (HCT-116) and human non-small-cell lung-cancer (NCI-H460) cells. Compound 5 exhibited the highest anticancer activity against the HCT-116 cell line, with an IC50 value of 1.64+/-0.06 microM. Compound 9 exhibited the highest cytotoxicity towards the NCI-H460 cell line, with an IC50 value of 0.43+/-0.02 microM.

  9. Structure elucidation of organic compounds from natural sources using 1D and 2D NMR techniques

    NASA Astrophysics Data System (ADS)

    Topcu, Gulacti; Ulubelen, Ayhan

    2007-05-01

    In our continuing studies on Lamiaceae family plants including Salvia, Teucrium, Ajuga, Sideritis, Nepeta and Lavandula growing in Anatolia, many terpenoids, consisting of over 50 distinct triterpenoids and steroids, and over 200 diterpenoids, several sesterterpenoids and sesquiterpenoids along with many flavonoids and other phenolic compounds have been isolated. For Salvia species abietanes, for Teucrium and Ajuga species neo-clerodanes for Sideritis species ent-kaurane diterpenes are characteristic while nepetalactones are specific for Nepeta species. In this review article, only some interesting and different type of skeleton having constituents, namely rearranged, nor- or rare diterpenes, isolated from these species will be presented. For structure elucidation of these natural diterpenoids intensive one- and two-dimensional NMR techniques ( 1H, 13C, APT, DEPT, NOE/NOESY, 1H- 1H COSY, HETCOR, COLOC, HMQC/HSQC, HMBC, SINEPT) were used besides mass and some other spectroscopic methods.

  10. Steroidal Saponins from the Rhizomes of Aspidistra typica

    PubMed Central

    Zhao, Yang; Zhao, Jian-Yuan; Zhang, Jie; Pang, Xu; Yu, He-Shui; Jia, De-Xian; Liu, Chao; Yu, Li-Yan; Ma, Bai-Ping

    2016-01-01

    Eleven new furostanol saponins, typaspidosides B-L (1–11), one new spirostanol saponin, typaspidoside M (12), and five known spirostanol saponins, 25S-atropuroside (13), neoaspidistrin (14), (25S)-pratioside D1 (15), 25S-aspidistrin (16) and 25S-neosibiricoside (17) were isolated from the rhizomes of Aspidistra typica Baill. The structures of the new compounds were established using 1D and 2D NMR (1H-1H COSY, HMQC, HMBC and ROESY) spectroscopy, high resolution mass spectrometry, and chemical methods. The aglycones of 1–3 (unusual furostanol saponins with opened E ring type), 9 and 10 (the methoxyl substituent at C-23 position) were found, identified from natural products for the first time. Moreover, the anti-HIV activities of the isolated steroidal glycosides were assessed, and compounds 13, 14, 16 and 17 exhibited high active against HIV-1. PMID:26937954

  11. Isolation of an alpha-methylene-gamma-butyrolactone derivative, a toxin from the plant pathogen Lasiodiplodia theobromae.

    PubMed

    He, Guochun; Matsuura, Hideyuki; Yoshihara, Teruhiko

    2004-10-01

    Lasiodiplodia theobromae is known as a multi-infectious microorganism that causes considerable crop damage, particularly to tropical fruits. When the fruits are infected by L. theobromae, the typical symptom is the appearance of black spots on the surface of the infected fruit. When injected in to the peel of banana, the culture filtrate of L. theobromae induced formation of black spots. The structure of the isolated compound responsible for this effect was determined to be (3S,4R)-3-carboxy-2-methylene-heptan-4-olide on the basis of analysis of MS, IR, and 1H and 13C NMR spectroscopic data, including HMQC, HMBC, and 1H-1H COSY experiments. The active compound was not only isolated from the culture filtrate derived from potato dextrose medium, but also from the extract of infected peels of bananas.

  12. Characterization of two minor saponins from Cordia piauhiensis by 1H and 13C NMR spectroscopy.

    PubMed

    Santos, Renata P; Silveira, Edilberto R; Lemos, Telma Leda G; Viana, Francisco Arnaldo; Braz-Filho, Raimundo; Pessoa, Otília Deusdênia L

    2005-06-01

    A careful NMR analysis with full assignment of the 1H and 13C spectral data for two minor saponins isolated from stems of Cordia piauhiensis is reported. These saponins were isolated by high-performance liquid chromatography and characterized as 3beta-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl]pomolic acid 28-O-[beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranosyl] ester (1) and 3beta-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl]oleanolic acid 28-O-[beta-D-xylopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranosyl] ester (2). Their structures were established using a combination of 1D and 2D (1H, 1H-COSY, TOCSY, NOESY, gs-HMQC and gs-HMBC) NMR techniques, electrospray ionization mass spectrometry and chemical evidence. Copyright 2005 John Wiley & Sons, Ltd.

  13. Experimental studies of the near threshold production of K{sup +}K{sup -} pairs at COSY-11

    SciTech Connect

    Gil, Damian; Smyrski, Jerzy

    2007-11-07

    This paper sums up experimental studies of the near threshold production of K{sup +}K{sup -} pairs at COSY-11. The total cross section of the reaction pp{yields}ppK{sup +}K{sup -} has been measured at five excess energies below the {phi} production threshold with the magnetic spectrometer COSY-11. The new data show a significant enhancement of the total cross section compared to pure phase space expectations.

  14. A polarized atomic-beam target for COSY-Jülich

    NASA Astrophysics Data System (ADS)

    Eversheim, P. D.; Altmeier, M.; Felden, O.; Glende, M.; Walker, M.; Hiemer, A.; Gebel, R.

    1998-01-01

    An atomic-beam target (ABT) for the EDDA experiment has been built in Bonn and was tested for the very first time at the cooler synchrotron COSY. The ABT differs from the polarized colliding-beams ion source for COSY in the DC-operation of the dissociator and the use of permanent 6-pole magnets. At present the beam optics of the ABT is set-up for maximum density in the interaction zone, but for target-cell operation it can be modified to give maximum intensity. The modular concept of this atomic ground-state target allows to provide all vector- (and tensor) polarizations for protons and deuterons, respectively. Up to now the polarization of the atomic-beam could be verified by the EDDA experiment to be ≳80% with a density in the interaction zone of ≳1011atoms/cm2.

  15. Polarized Negative Light Ions at the Cooler Synchrotron COSY/Juelich

    SciTech Connect

    Gebel, R.; Felden, O.; Rossen, P. von

    2005-04-06

    The polarized ion source at the cooler synchrotron facility COSY of the research centre Juelich in Germany delivers negative polarized protons or deuterons for medium energy experiments. The polarized ion source, originally built by the universities of Bonn, Erlangen and Cologne, is based on the colliding beams principle, using after an upgrade procedure an intense pulsed neutralized caesium beam for charge exchange with a pulsed highly polarized hydrogen beam. The source is operated at 0.5 Hz repetition rate with 20 ms pulse length, which is the maximum useful length for the injection into the synchrotron. Routinely intensities of 20 {mu}Amore » are delivered for injection into the cyclotron of the COSY facility. For internal targets the intensity of 2 mA and a polarization up to 90% have been reached. Reliable long-term operation for experiments at COSY for up to 9 weeks has been achieved. Since 2003 polarized deuterons with different combinations of vector and tensor polarization were delivered to experiments.« less

  16. The Scalar Resonances a0/f0(980) at COSY

    SciTech Connect

    Buescher, M.

    2006-02-11

    Fundamental properties of the scalar resonances a0/f0(980), like their masses, widths and couplings to KK-bar, are poorly known. In particular, precise knowledge of the latter quantity would be of great importance since it can be related to the KK-bar content of these resonances.An experimental program is under way at COSY-Juelich aiming at the extraction of the isospin violating a0/f0 mixing amplitude {lambda} which is in leading order proportional to the product of the coupling constants of the a0 and f0 to kaons. a0/f0 production is studied in pp, pn and dd interactions, both for the KK-bar and the {pi}{eta}/{pi}{pi} decays,more » using the ANKE and WASA spectrometers. The latter will be available for measurements at COSY in 2007.As a first step, isovector KK-bar production has been measured in the reaction pp {yields} dK+K-bar0. The data reveal dominance of the a{sub 0}{sup +} channel, thus demonstrating the feasibility of scalar meson studies at COSY. Analyses of KK-bar- and K-bard-FSI effects yield the corresponding scattering lengths, a(KK-bar)I=1 = -(0.02 {+-} 0.03) - i(0.61 {+-} 0.05) fm and vertical bar Re a(K-bard) vertical bar {<=}1.3 fm, Im a(K-bard){<=}1.3 fm.« less

  17. Xenon-ion-induced and thermal mixing of Co/Si bilayers and their interplay

    NASA Astrophysics Data System (ADS)

    Novaković, M.; Zhang, K.; Popović, M.; Bibić, N.; Hofsäss, H.; Lieb, K. P.

    2011-05-01

    Studies on ion-irradiated transition-metal/silicon bilayers demonstrate that interface mixing and silicide phase formation depend sensitively on the ion and film parameters, including the structure of the metal/Si interface. Thin Co layers e-gun evaporated to a thickness of 50 nm on Si(1 0 0) wafers were bombarded at room temperature with 400-keV Xe + ions at fluences of up to 3 × 10 16 cm -2. We used either crystalline or pre-amorphized Si wafers the latter ones prepared by 1.0-keV Ar-ion implantation. The as-deposited or Xe-ion-irradiated samples were then isochronally annealed at temperatures up to 700 °C. Changes of the bilayer structures induced by ion irradiation and/or annealing were investigated with RBS, XRD and HRTEM. The mixing rate for the Co/c-Si couples, Δ σ2/ Φ = 3.0(4) nm 4, is higher than the value expected for ballistic mixing and about half the value typical for spike mixing. Mixing of pre-amorphized Si is much weaker relative to crystalline Si wafers, contrary to previous results obtained for Fe/Si bilayers. Annealing of irradiated samples produces very similar interdiffusion and phase formation patterns above 400 °C as in the non-irradiated Co/Si bilayers: the phase evolution follows the sequence Co 2Si → CoSiCoSi 2.

  18. Negative ion source development at the cooler synchrotron COSY/Jülich

    NASA Astrophysics Data System (ADS)

    Felden, O.; Gebel, R.; Maier, R.; Prasuhn, D.

    2013-02-01

    The Nuclear Physics Institute at the Forschungszentrum Jülich, a member of the Helmholtz Association, conducts experimental and theoretical basic research in the field of hadron, particle, and nuclear physics. It operates the cooler synchrotron COSY, an accelerator and storage ring, which provides unpolarized and polarized proton and deuteron beams with beam momenta of up to 3.7 GeV/c. Main activities of the accelerator division are the design and construction of the high energy storage ring HESR, a synchrotron and part of the international FAIR project, and the operation and development of COSY with injector cyclotron and ion sources. Filament driven volume sources and a charge exchange colliding beams source, based on a nuclear polarized atomic beam source, provide unpolarized and polarized H- or D- routinely for more than 6500 hours/year. Within the Helmholtz Association's initiative Accelerator Research and Development, ARD, the existing sources at COSY, as well as new sources for future programs, are investigated and developed. The paper reports about these plans, improved pulsed beams from the volume sources and the preparation of a source for the ELENA project at CERN.

  19. The Storage Cell for the Tri-Experiment at COSY-JÜLICH

    NASA Astrophysics Data System (ADS)

    Felden, O.; Gebel, R.; Glende, M.; Lehrach, A.; Maier, R.; Prasuhn, D.; von Rossen, P.; Bisplinghoff, J.; Eversheim, P. D.; Hinterberger, F.

    2002-04-01

    At the EDDA experiment in the cooler synchrotron COSY in Jülich an atomic beam target is used which provides the designed polarization and density distribution. To increase the target density significantly a storage cell has been developed and implemented. This will contribute to a higher accuracy for the test of Time Reversal Invariance (TRI) which will be performed at the EDDA target place. To obtain the higher luminosity the target density and the transmission of the COSY beam through the cell were determined in their dependence on the cell aperture. Low storage cell apertures increase the target density in the cell but reduce the transmission of the circulating proton beam. To find the optimal cell design the transmission of the COSY beam was measured with movable scrapers and tested with an aperture at EDDA simulating the storage cell. The target density was calculated by Monte Carlo simulations for several cell geometries. An additional gain in target density is achieved by cooling the cell. A Teflon coating of the cell reduces depolarization of the target gas. First measurements with the EDDA detector have shown that the target density as well as the polarization are within the range of the expected values.

  20. Magnetic structure of the ferromagnetic new ternary silicide Nd5CoSi2.

    PubMed

    Mayer, C; Gaudin, E; Gorsse, S; Porcher, F; André, G; Chevalier, B

    2012-04-04

    Nd(5)CoSi(2) was obtained from the elements by arc-melting followed by annealing at 883 K. Its investigation by single-crystal x-ray and neutron powder diffraction shows that this ternary silicide crystallizes as Nd(5)Si(3) in a tetragonal structure deriving from the Cr(5)B(3)-type (I4/mcm space group; a = 7.7472(2) and c = 13.5981(5) Å as unit cell parameters). The structural refinements confirm the mixed occupancy on the 8h site between Si and Co atoms, as already observed for Gd(5)CoSi(2). Magnetization and specific heat measurements reveal a ferromagnetic behavior below T(C) = 55 K for Nd(5)CoSi(2). This magnetic ordering is further evidenced by neutron powder diffraction investigation revealing between 1.8 K and T(C) a canted ferromagnetic structure in the direction of the c-axis described by a propagation vector k = (0 0 0). At 1.8 K, the two Nd(3+) ions carry ordered magnetic moments equal respectively to 1.67(7) and 2.37(7) μ(B) for Nd1 and Nd2; these two moments exhibit a canting angle of θ = 4.3(6)°. This magnetic structure presents some similarities with that reported for Nd(5)Si(3). © 2012 IOP Publishing Ltd

  1. Transmission electron microscopy study of the formation of epitaxial CoSi2/Si (111) by a room-temperature codeposition technique

    NASA Technical Reports Server (NTRS)

    D'Anterroches, Cecile; Yakupoglu, H. Nejat; Lin, T. L.; Fathauer, R. W.; Grunthaner, P. J.

    1988-01-01

    Co and Si have been codeposited on Si (111) substrates near room temperature in a stoichiometric 1:2 ratio in a molecular beam epitaxy system. Annealing of these deposits yields high-quality single-crystal CoSi2 layers. Transmission electron microscopy has been used to examine as-deposited layers and layers annealed at 300, 500, and 600 C. Single-crystal epitaxial grains of CoSi2 embedded in a matrix of amorphous Co/Si are observed in as-deposited samples, while the layer is predominantly single-crystal, inhomogeneously strained CoSi2 at 300 C. At 600 C, a homogeneously strained single-crystal layer with a high density of pinholes is observed. In contrast to other solid phase epitaxy techniques used to grow CoSi2 on Si (111), no intermediate silicide phases are observed prior to the formation of CoSi2.

  2. A new COmpact hyperSpectral Imaging system (COSI) for UAS

    NASA Astrophysics Data System (ADS)

    Sima, Aleksandra; Baeck, Pieter-Jan; Delalieux, Stephanie; Livens, Stefan; Blommaert, Joris; Delauré, Bavo; Boonen, Miet

    2016-04-01

    This presentation gives an overview of the new COmpact hyperSpectral Imaging (COSI) system recently developed at the Flemish Institute for Technological Research (VITO, Belgium) and suitable for multirotor Remotely Piloted Aircraft Systems (RPAS) platforms. The camera is compact and lightweight, with a total mass of less than 500g including: an embedded computer, storage and power distribution unit. Such device miniaturization was possible thanks to the application of linear variable filters technology, in which image lines in the across flight direction correspond to different spectral bands as well as a different location on the ground (frame camera). The scanning motion is required to retrieve the complete spectrum for every point on the ground. The COSI camera captures data in 72 narrow (FWHM: 5nm to 10 nm) bands in the spectral range of 600-900 nm. Such spectral information is highly favourable for vegetation studies, since the main chlorophyll absorption feature centred around 680 nm is measured, as well as, the red-edge region (680 nm to 730 nm) which is often linked to plant stress. The NIR region furthermore reflects the internal plant structure, and is often linked to leaf area index and plant biomass. Next to the high spectral resolution, the COSI imager also provides a very high spatial data resolution i.e. images captured with a 9mm lens at 40m altitude cover a swath of ~40m with a ~2cm ground sampling distance. A dedicated data processing chain transforms the raw images into various information and action maps representing the status of the vegetation health and thus allowing for optimization of the management decisions within agricultural fields. In a number of test flights, hyperspectral COSI imager data were acquired covering diverse environments, e.g.: strawberry fields, natural grassland or pear orchards. Next to the COSI system overview, examples of collected data will be presented together with the results of the spectral data analysis. Lessons

  3. Study on Dendrobium officinale O-acetyl-glucomannan (Dendronan®): part II. Fine structures of O-acetylated residues.

    PubMed

    Xing, Xiaohui; Cui, Steve W; Nie, Shaoping; Phillips, Glyn O; Goff, H Douglas; Wang, Qi

    2015-03-06

    Main objective of this study was to investigate the detailed structural information about O-acetylated sugar residues in Dendronan(®). A water solution (2%, w/w) of Dendronan(®) was treated with endo-β-mannanase to produce oligosaccharides rich in O-acetylated sugar residues. The oligosaccharides were partly recovered by ethanol precipitation (70%, w/w). The recovered sample (designated Hydrolyzed Dendrobium officinale Polysaccharide, HDOP) had a yield of 24.7% based on the dry weight of Dendronan(®) and was highly O-acetylated. A D2O solution of HDOP (6%, w/w) generated strong signals in (1)H, (13)C, 2D (1)H-(1)H COSY, 2D (1)H-(1)H TOCSY, 2D (1)H-(1)H NOESY, 2D (1)H-(13)C HMQC, and 2D (1)H-(13)C HMBC NMR spectra. Results of NMR analyses showed that the majority of O-acetylated mannoses were mono-substituted with acetyl groups at O-2 or O-3 position. There were small amounts of mannose residues with di-O-acetyl substitution at both O-2 and O-3 positions. Minor levels of mannoses with 6-O-acetyl, 2,6-di-O-acetyl, and 3,6-di-O-acetyl substitutions were also identified. Much information about sugar residue sequence was extracted from 2D (1)H-(13)C HMBC and 2D (1)H-(1)H NOESY spectra. (1)J(C-H) coupling constants of major sugar residues were obtained. Evidences for the existence of branches or O-acetylated glucoses in HDOP were not found. The major structure of Dendronan(®) is shown as follows: [Formula: see text] M: β-D-mannopyranose; G: β-D-glucopyranose; a: O-acetyl group. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  4. First Experiments with the Polarized Internal Gas Target (PIT) at ANKE/COSY

    SciTech Connect

    Engels, R.; Lorentz, B.; Prasuhn, D.

    2008-02-06

    For future few-nucleon interaction studies with polarized beams and targets at COSY-Juelich, a polarized internal storage-cell gas target was implemented at the magnet spectrometer ANKE in summer 2005. First commissioning of the polarized Atomic Beam Source (ABS) at ANKE was carried out and some improvements of the system have been done. Storage-cell tests to determine the COSY beam dimensions have been performed. Electron cooling combined with stacking and stochastic cooling have been studied. Experiments with N{sub 2} gas in the storage cell to simulate the background produced by beam interaction with the aluminum cell walls were performed to investigate themore » beam heating by the target gas. The analysis of the d-vector p-vector {yields}dp and d-vector p-vector{yields}(dp{sub sp}){pi}{sup 0} reactions showed that events from the extended target can be clearly identified in the ANKE detector system.The polarization of the atomic beam of the ABS, positioned close to the strong dipole magnet D2 of ANKE, was tuned with a Lamb-shift polarimeter (LSP) beneath the target chamber. With use of the known analyzing powers of the quasi-free np{yields}d{pi}{sup 0} reaction, the polarization in the storage cell was measured to be Q{sub y} = 0.79{+-}0.07 in the vertical stray field of the D2 magnet acting as a holding field. The achieved target thickness was 2x10{sup 13} atoms/cm{sup 2} for one hyperfine state populated in the ABS beam only. With a COSY beam intensity of 6x10{sup 9} stored polarized deuterons in the ring, the luminosity for double polarized experiments was 1x10{sup 29} cm{sup -2} s{sup -1}.« less

  5. First Experiments with the Polarized Internal Gas Target (PIT) at ANKE/COSY

    SciTech Connect

    Engels, R.; Lorentz, B.; Prasuhn, D.

    2009-08-04

    For future few-nucleon interaction studies with polarized beams and targets at COSY-Juelich, a polarized internal storage-cell gas target was implemented at the magnet spectrometer ANKE. First commissioning of the polarized Atomic Beam Source (ABS) at ANKE was carried out and some improvements of the system have been done. Storage-cell tests to determine the COSY beam dimensions have been performed. Electron cooling combined with stacking and stochastic cooling have been studied. Experiments with N{sub 2} gas in the storage cell to simulate the background produced by beam interaction with the aluminum cell walls were performed to investigate the beam heating bymore » the target gas. The analysis of the d-vectorp-vector->dp and d-vectorp-vector->(dp{sub sp})pi{sup 0} reactions showed that events from different positions of the extended target can be clearly identified in the ANKE detector system. The polarization of the atomic beam of the ABS, positioned close to the strong dipole magnet D2 of ANKE, was tuned with a Lamb-shift polarimeter (LSP) beneath the target chamber. With use of the known analyzing powers of the quasi-free np->dpi{sup 0} reaction, the polarization in the storage cell was measured to be Q{sub y} = 0.79+-0.07 in the vertical stray field of the D2 magnet acting as a holding field. The target thickness achieved was 2x10{sup 13} atoms/cm{sup 2} for one hyperfine state populated in the ABS beam only. With a COSY beam intensity of 6x10{sup 9} stored polarized deuterons in the ring, the luminosity for double polarized experiments was 1x10{sup 29} cm{sup -2} s{sup -1}.« less

  6. Search for {eta}-mesic helium using WASA-at-COSY

    SciTech Connect

    Moskal, P.; Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, Juelich

    2010-08-05

    The installation of the WASA detector at the cooler synchrotron COSY opened the possibility to search for {eta}-mesic helium with high statistics and high acceptance. A search for the {sup 4}He--{eta} bound state is conducted via an exclusive measurement of the excitation function for the dd{yields}{sup 3}Hep{pi}{sup -} reaction varying continuously the beam momentum around the threshold for the dd{yields}{sup 4}He{eta} reaction. Ramping of the beam momentum and taking advantage of the large acceptance of the WASA detector allows to minimize systematical uncertainities.

  7. Synthesis of Amorphous Powders of Ni-Si and Co-Si Alloys by Mechanical Alloying

    NASA Astrophysics Data System (ADS)

    Omuro, Keisuke; Miura, Harumatsu

    1991-05-01

    Amorphous powders of the Ni-Si and Co-Si alloys are synthesized by mechanical alloying (MA) from crystalline elemental powders using a high energy ball mill. The alloying and amorphization process is examined by X-ray diffraction, differential scanning calorimetry (DSC), and scanning electron microscopy. For the Ni-Si alloy, it is confirmed that the crystallization temperature of the MA powder, measured by DSC, is in good agreement with that of the powder sample prepared by mechanical grinding from the cast alloy ingot products of the same composition.

  8. Spacer layer thickness dependent structural and magnetic properties of Co/Si multilayers

    NASA Astrophysics Data System (ADS)

    Roy, Ranjan; Singh, Dushyant; Kumar, M. Senthil

    2018-05-01

    In this article, the study of high resolution x-ray diffraction and magnetization of sputter deposited Co/Si multilayer is reported. Multilayers are prepared at ambient temperature by dc magnetron sputtering. Structural properties are studied by high resolution x-ray diffraction. Magnetic properties are studied at room temperature by vibrating sample magnetometer. Structural properties show that the Co layer is polycrystalline and the Si layer is amorphous. The magnetization study indicates that the samples are soft ferromagnetic in nature. The study of magnetization also shows that the easy axis of magnetization lies in the plane of the film.

  9. COSY-11: an Experimental Facility for Studying Meson Production in Free and Quasi-free Nucleon-Nucleon Collisions

    SciTech Connect

    Klaja, P.; Janusz, M.; Jarczyk, L.

    2005-10-26

    The COSY-11 experimental setup is an internal facility installed at the COoler SYnchrotron COSY in Juelich. It allows to investigate meson production in free and quasi-free nucleon-nucleon collisions, eg. pp {yields} pp meson and pd {yields} pspnp meson reactions. Drift chambers and scintillators permit to measure outgoing protons, separated in the magnetic field of the COSY-11 dipole. Neutrons are registered in the neutron modular detector installed downstream from the target. Recently, the experimental setup has been extended with spectator detector, deuteron drift chamber and polarization monitoring system, and since then meson production can be investigated also as a function ofmore » spin and isospin of colliding nucleons.« less

  10. Kaon pair production in pp, pd and dd collisions at COSY

    SciTech Connect

    Hartmann, M.; Dzyuba, A.; Keshelashvili, I.

    2010-08-05

    The near-threshold production of kaon-pairs has been investigated in proton-proton, proton-deuteron and deuteron-deuteron collisions at the Cooler Synchrotron COSY. The excitation function for the pp{yields}ppK{sup +}K{sup -} reaction and the invariant K{sup -}p, K{sup -}pp, and K{sup +}K{sup -} mass distributions indicate the presence of both K{sup -}p and K{sup +}K{sup -} final state interactions. Analogous final-state interactions of antikaons with deuterons has been found in the pp{yields}dK{sup +}K{sup 0}-bar reaction as well as in the pn{yields}dK{sup +}K{sup -} reaction, measured in the quasi-free pd{yields}p{sub sp}dK{sup +}K{sup -} process with a 'spectator' proton (p{sub sp}). The existing COSY data onmore » the pd{yields}{sup 3}HeK{sup +}K{sup -} reaction are not yet sufficient to study the K{sup -3}He and K{sup +}K{sup -} final state interactions. A very small total cross section was found for the dd{yields}{sup 4}HeK{sup +}K{sup -} reaction.« less

  11. From CELSIUS to COSY: on the observation of a dibaryon resonance

    NASA Astrophysics Data System (ADS)

    Clement, H.; Bashkanov, M.; Skorodko, T.

    2015-11-01

    Using a high-quality beam of storage rings in combination with a pellet target and a hermetic WASA detector covering practically the full solid angle, two-pion production in nucleon-nucleon collisions has been systematically studied by exclusive and kinematically complete measurements—first at CELSIUS and subsequently at COSY. These measurements resulted in a detailed understanding of the two-pion production mechanism by t-channel meson exchange. The investigation of the ABC effect, which denotes an unusual low-mass enhancement in the ππ-invariant mass spectrum, in double-pionic fusion reactions led the trace to the observation of a narrow dibaryon resonance with I({J}P)=0({3}+) about 80 MeV below the nominal mass of the conventional Δ Δ system. New neutron-proton scattering data, taken with a polarized beam at COSY, produced a pole in the coupled {}3{D}3-3{G}3 partial waves at (2380+/- 10\\-\\i\\40+/- 5) MeV, establishing thus the first observation of a genuine s-channel dibaryon resonance.

  12. Results from EDDAatCOSY: Spin Observables in Proton-Proton Elastic Scattering

    NASA Astrophysics Data System (ADS)

    Rohdjeß, Heiko

    2003-07-01

    Elastic proton-proton scattering as one of the fundamental hadronic reactions has been studied with the internal target experiment EDDA at the Cooler-Synchrotron COSY/Jülich. A precise measurement of differential cross section, analyzing power and three spin-correlation parameters over a large angular (θc.m. ≈ 35° - 90°) and energy (Tp ≈ 0.5 - 2.5 GeV) range has been carried out in the past years. By taking scattering data during the acceleration of the COSY beam, excitation functions were measured in small energy steps and consistent normalization with respect to luminosity and polarization. The experiment uses internal fiber targets and a polarized hydrogen atomic-beam target in conjunction with a double-layered, cylindrical scintillator hodoscope for particle detection. The results on differential cross sections and analyzing powers have been published and helped to improve phase shift solutions. Recently data taking with polarized beam and target has been completed. Preliminary results for the spin-correlation parameters A NN, ASS, and ASL are presented. The observable ASS has been measured the first time above 800 MeV and our results are in sharp contrast to phase-shift predictions at higher energies. Our analysis shows that some of the ambiguities in the direct reconstruction of scattering amplitudes which also show up as differences between available phase-shift solutions, will be reduced by these new measurements.

  13. Antimalarial (+)-trans-hexahydrodibenzopyran derivatives from Machaerium multiflorum.

    PubMed

    Muhammad, I; Li, X C; Dunbar, D C; ElSohly, M A; Khan, I A

    2001-10-01

    Bioassay-guided fractionation of Machaerium multiflorum yielded the hitherto unreported (+)-trans-hexahydrodibenzopyrans machaeriol A (1) and machaeriol B (2), as well as the known guaiane sesquiterpene (-)-kessane. Structure elucidation was based on (1)H and (13)C NMR data, mainly 2D NMR (1)H-(1)H COSY, (1)H-(13)C HMQC, (1)H-(13)C HMBC, and (1)H-(1)H NOESY experiments. This is the first report of the hexahydrodibenzopyrans from a higher plant other than the genus Cannabis. The cannabimimetic activity was thus evaluated by radioligand binding assay for cannabinoid receptor CB1, which indicated, notably, that both 1 and 2 were inactive. In addition, the cross reactivity of 1 and 2 toward antibodies designed for urinary metabolites of cannabinoids was evaluated with the EMIT and On Line cannabinoids assays. Both compounds showed no response at 100 000 ng/mL in both assays. Machaeriol B (2) demonstrated in vitro antimalarial activity (IC(50) = 120 ng/mL) against Plasmodium falciparum W-2 clone.

  14. The Composite Strain Index (COSI) and Cumulative Strain Index (CUSI): methodologies for quantifying biomechanical stressors for complex tasks and job rotation using the Revised Strain Index.

    PubMed

    Garg, Arun; Moore, J Steven; Kapellusch, Jay M

    2017-08-01

    The Composite Strain Index (COSI) quantifies biomechanical stressors for complex tasks consisting of exertions at different force levels and/or with different exertion times. The Cumulative Strain Index (CUSI) further integrates biomechanical stressors from different tasks to quantify exposure for the entire work shift. The paper provides methodologies to compute COSI and CUSI along with examples. Complex task simulation produced 169,214 distinct tasks. Use of average, time-weighted average (TWA) and peak force and COSI classified 66.9, 28.2, 100 and 38.9% of tasks as hazardous, respectively. For job rotation the simulation produced 10,920 distinct jobs. TWA COSI, peak task COSI and CUSI classified 36.5, 78.1 and 66.6% jobs as hazardous, respectively. The results suggest that the TWA approach systematically underestimates the biomechanical stressors and peak approach overestimates biomechanical stressors, both at the task and job level. It is believed that the COSI and CUSI partially address these underestimations and overestimations of biomechanical stressors. Practitioner Summary: COSI quantifies exposure when applied hand force and/or duration of that force changes during a task cycle. CUSI integrates physical exposures from job rotation. These should be valuable tools for designing and analysing tasks and job rotation to determine risk of musculoskeletal injuries.

  15. Operation of Negative Ion Sources at the Cooler Synchrotron COSY/Juelich

    SciTech Connect

    Gebel, R.; Felden, O.; Maier, R.

    2011-09-26

    The Institute for Nuclear Physics at the Forschungszentrum Juelich is dedicated to fundamental research in the field of hadron, particle and nuclear physics. Main activities are the development of the High Energy Storage Ring for the Facility for Antiproton and Ion Research at Darmstadt and the operation and improvement of the cooler synchrotron COSY at Juelich. The injector, a cyclotron with polarized and unpolarized H{sup -} and D{sup -} sources, has exceeded 7000 hours availability per year, averaged over the last decade. Work in progress is the investigation of production, extraction and transport of the low energy 4.5 keV/u ionmore » beams. A brief overview of the activities is presented.« less

  16. Study of charge symmetry breaking in dd collisions with WASA-at-COSY

    SciTech Connect

    Wronska, Aleksandra

    2011-10-24

    Charge symmetry is an approximate symmetry of the strong interaction. Studies of its breaking can yield information on the u and d quark mass difference. A theoretical collaboration is currently working on the description of charge symmetry breaking mechanisms for dd{yields}{alpha}{pi}{sup 0} and np{yields}d{pi}{sup 0} within Chiral Perturbation Theory, using the data from TRI-UMF and IUCF. One of the items in the program of the WASA-at-COSY collaboration is to extend the data base for the dd{yields}{alpha}{pi}{sup 0} reaction to higher energies, which would allow the extraction of the information on the p-wave. Status of the analysis of experimental data alongmore » with the preliminary results from the pilot run will be presented here.« less

  17. A thin gold coated hydrogen heat pipe-cryogenic target for external experiments at COSY

    NASA Astrophysics Data System (ADS)

    Abdel-Bary, M.; Abdel-Samad, S.; Elawadi, G. A.; Kilian, K.; Ritman, J.

    2009-05-01

    A gravity assisted Gold coated heat pipe (GCHP) with 5-mm diameter has been developed and tested to cool a liquid hydrogen target for external beam experiments at COSY. The need for a narrow target diameter leads us to study the effect of reducing the heat pipe diameter to 5 mm instead of 7 mm, to study the effect of coating the external surface of the heat pipe by a shiny gold layer (to decrease the radiation heat load), and to study the effect of using the heat pipe without using 20 layers of' super-insulation around it (aluminized Mylar foil) to keep the target diameter as small as possible. The developed gold coated heat pipe was tested with 20 layers of super-insulation (WI) and without super-insulation (WOI). The operating characteristics for both conditions were compared to show the advantages and disadvantages.

  18. Early stages of epitaxial CoSi 2 formation on Si(111) surface as investigated by ARUPS, XPS, LEED and work function variation

    NASA Astrophysics Data System (ADS)

    Pirri, C.; Peruchetti, J. C.; Gewinner, G.; Derrien, J.

    1985-04-01

    We performed the CoSi 2 formation on a clean (7 × 7) Si(111) surface under UHV conditions. The used techniques were angle resolved UV photoemission, X-ray photoemission, work function change and low energy electron diffraction in order to study the electronic and structural properties of the interface during its formation. At room temperature, a small amount of Co reacts strongly with Si to form an interfacial and very thin cobalt suicide. The ultraviolet photoelectron spectrum displays already two features corresponding respectively to the Co 3d and Si 3p electron bonding states and the Co 3d non-bonding states. With increasing coverage ( θ ≳ 4 ML) it seems that the interfacial suicide prevents further Co-Si interdiffusion to achieve the suicide reaction and a metal rich film is found. At high temperature (˜ 600°C) and in the first monolayer range, several superstructures are found (√7 × √7, and 2 × 2). They are induced by a Co-Si bidimensional compound where the Co atoms are not yet completely surrounded by Si atoms as in their bulk CoSi 2 structure. With increasing coverage, a CoSi 2-like photoemission spectrum is observed reflecting the formation of the disilicide. The LEED pattern testifies an epitaxial growth displaying a (1 × 1) CoSi 2 diagram. The work function change technique also reflects faithfully this growth.

  19. Room-temperature codeposition growth technique for pinhole reduction in epitaxial CoSi2 on Si (111)

    NASA Technical Reports Server (NTRS)

    Lin, T. L.; Fathauer, R. W.; Grunthaner, P. J.; D'Anterroches, C.

    1988-01-01

    A solid-phase epitaxy has been developed for the growth of CoSi2 films on Si (111) with no observable pinholes (1000/sq cm detection limit). The technique utilizes room-temperature codeposition of Co and Si in stoichiometric ratio, followed by the deposition of an amorphous Si capping layer and subsequent in situ annealing at 550-600 C. CoSi2 films grown without the Si cap are found to have pinhole densities of (1-10) x 10 to the 7th/sq cm when annealed at similar temperatures. A CF4 plasma-etching technique was used to increase the visibility of the pinholes in the silicide layer.

  20. Compact Hyperspectral Imaging System (cosi) for Small Remotely Piloted Aircraft Systems (rpas) - System Overview and First Performance Evaluation Results

    NASA Astrophysics Data System (ADS)

    Sima, A. A.; Baeck, P.; Nuyts, D.; Delalieux, S.; Livens, S.; Blommaert, J.; Delauré, B.; Boonen, M.

    2016-06-01

    This paper gives an overview of the new COmpact hyperSpectral Imaging (COSI) system recently developed at the Flemish Institute for Technological Research (VITO, Belgium) and suitable for remotely piloted aircraft systems. A hyperspectral dataset captured from a multirotor platform over a strawberry field is presented and explored in order to assess spectral bands co-registration quality. Thanks to application of line based interference filters deposited directly on the detector wafer the COSI camera is compact and lightweight (total mass of 500g), and captures 72 narrow (FWHM: 5nm to 10 nm) bands in the spectral range of 600-900 nm. Covering the region of red edge (680 nm to 730 nm) allows for deriving plant chlorophyll content, biomass and hydric status indicators, making the camera suitable for agriculture purposes. Additionally to the orthorectified hypercube digital terrain model can be derived enabling various analyses requiring object height, e.g. plant height in vegetation growth monitoring. Geometric data quality assessment proves that the COSI camera and the dedicated data processing chain are capable to deliver very high resolution data (centimetre level) where spectral information can be correctly derived. Obtained results are comparable or better than results reported in similar studies for an alternative system based on the Fabry-Pérot interferometer.

  1. Experimental study of pp{eta} dynamics with WASA-at-COSY

    SciTech Connect

    Shah, Neha

    2011-10-24

    To investigate the interaction of {eta}-meson with the nucleons, its production, near the kinematical threshold, in proton-proton collisions has been studied with the WASA detector at COSY storage ring in Juelich, Germany. The data has been taken at beam energy 1400 MeV (corresponding to excess energy (Q = 57 MeV). The {eta}-meson was detected via its 3{pi}{sup 0} decay in nearly 4{pi} detector and two protons were measured in forward direction. The determination of four vectors of both protons and the {eta}-meson in the final state allowed to derive complete kinematical information of the pp{eta}-system. The analysis resulted in 9x10{supmore » 6} events of {eta}{yields}3{pi}{sup 0} giving total production cross-section (8.87{+-}0.03{sub stat}{+-}2.57{sub sys}){mu}b. The angular distribution of {eta}-meson in the center of mass frame is anisotropic and squared invariant mass distributions for proton-proton and proton-{eta} shows deviation from pure phase space.« less

  2. Magnetic switching, relaxation, and domain structure of a Co/Si(111) film

    NASA Astrophysics Data System (ADS)

    Baird, M. J.; Bland, J. A. C.; Gu, E.; Ives, A. J. R.; Schumann, F. O.; Hughes, H. P.

    1993-11-01

    We have used scanning magneto-optic Kerr effect (MOKE) microscopy to investigate the magnetic relaxation of a polycrystalline hcp 125 Å Co/Si(111) film with planar uniaxial anisotropy, on time scales between 10 and 2400 s and with a spatial resolution of 15 μm. In a static magnetic field slightly less than the coercive field and applied along the easy axis direction, domains develop and the magnetization reversal proceeds via displacements of 180° domain walls. Microscopic images of this metastable state allow the 180° domains to be identified by calibration of the MOKE signal with respect to that for the saturated magnetization states. The 180° reversed domains are observed to grow in the direction of the field in the form of narrow fingers, extending via short Barkhausen jumps, randomly spaced in time over the entire time-scale range investigated, with typical distances between pinning sites of the order of microns. This reversal behavior is qualitatively similar to that reported for Au/Co perpendicular anisotropy films a few monolayers thick.

  3. The control system of the polarized internal target of ANKE at COSY

    NASA Astrophysics Data System (ADS)

    Kleines, H.; Sarkadi, J.; Zwoll, K.; Engels, R.; Grigoryev, K.; Mikirtychyants, M.; Nekipelov, M.; Rathmann, F.; Seyfarth, H.; Kravtsov, P.; Vasilyev, A.

    2006-05-01

    The polarized internal target for the ANKE experiment at the Cooler Synchrotron COSY of the Forschungszentrum Jülich utilizes a polarized atomic beam source to feed a storage cell with polarized hydrogen or deuterium atoms. The nuclear polarization is measured with a Lamb-shift polarimeter. For common control of the two systems, industrial equipment was selected providing reliable, long-term support and remote control of the target as well as measurement and optimization of its operating parameters. The interlock system has been implemented on the basis of SIEMENS SIMATIC S7-300 family of programmable logic controllers. In order to unify the interfacing to the control computer, all front-end equipment is connected via the PROFIBUS DP fieldbus. The process control software was implemented using the Windows-based WinCC toolkit from SIEMENS. The variety of components, to be controlled, and the logical structure of the control and interlock system are described. Finally, a number of applications derived from the present development to other, new installations are briefly mentioned.

  4. Electromagnetic Transition Form Factor of the η meson with WASA-at-COSY

    NASA Astrophysics Data System (ADS)

    Goswami, A.

    2016-11-01

    In this work we present a study of the Dalitz decay η → γe+e-. The aim of this work is to measure the transition form factor of the η meson. The transition form factor of the η meson describes the electromagnetic structure of the meson. The study of the Dalitz decay helps to calculate the transition form factor of the η meson. When a particle is point-like it's decay rate can be calculated within QED. However, the complex structure of the meson modifies its decay rate. The transition form factor is determined by comparing the lepton-antilepton invariant mass distribution with QED. For this study data on proton-proton reaction at a beam energy of 1.4 GeV has been collected with WASA-at-COSY detector at Forschungszentrum Juelich, Germany. In the higher invariant mass region recent theoretical calculations slightly deviate from the fit to the data. We expect better results in the higher invariant mass region than previous measurements. The preliminary results of the analysis will be presented.

  5. Effect of local atomic and electronic structures on thermoelectric properties of chemically substituted CoSi

    NASA Astrophysics Data System (ADS)

    Hsu, C. C.; Pao, C. W.; Chen, J. L.; Chen, C. L.; Dong, C. L.; Liu, Y. S.; Lee, J. F.; Chan, T. S.; Chang, C. L.; Kuo, Y. K.; Lue, C. S.

    2014-05-01

    We report the effects of Ge partial substitution for Si on local atomic and electronic structures of thermoelectric materials in binary compound cobalt monosilicides (\\text{CoSi}_{1-x}\\text{Ge}_{x}\\text{:}\\ 0 \\le x \\le 0.15 ). Correlations between local atomic/electronic structure and thermoelectric properties are investigated by means of X-ray absorption spectroscopy. The spectroscopic results indicate that as Ge is partially substituted onto Si sites at x \\le 0.05 , Co in CoSi1-xGex gains a certain amount of charge in its 3d orbitals. Contrarily, upon further replacing Si with Ge at x \\ge 0.05 , the Co 3d orbitals start to lose some of their charge. Notably, thermopower is strongly correlated with charge redistribution in the Co 3d orbital, and the observed charge transfer between Ge and Co is responsible for the variation of Co 3d occupancy number. In addition to Seebeck coefficient, which can be modified by tailoring the Co 3d states, local lattice disorder may also be beneficial in enhancing the thermoelectric properties. Extended X-ray absorption fine structure spectrum results further demonstrate that the lattice phonons can be enhanced by Ge doping, which results in the formation of the disordered Co-Co pair. Improvements in the thermoelectric properties are interpreted based on the variation of local atomic and electronic structure induced by lattice distortion through chemical substitution.

  6. Studies of the Twin Helix Parametric-resonance Ionization Cooling Channel with COSY INFINITY

    SciTech Connect

    J.A. Maloney, K.B. Beard, R.P. Johnson, A. Afanasev, S.A. Bogacz, Y.S. Derbenev, V.S. Morozov, B. Erdelyi

    2012-07-01

    A primary technical challenge to the design of a high luminosity muon collider is an effective beam cooling system. An epicyclic twin-helix channel utilizing parametric-resonance ionization cooling has been proposed for the final 6D cooling stage. A proposed design of this twin-helix channel is presented that utilizes correlated optics between the horizontal and vertical betatron periods to simultaneously focus transverse motion of the beam in both planes. Parametric resonance is induced in both planes via a system of helical quadrupole harmonics. Ionization cooling is achieved via periodically placed wedges of absorbing material, with intermittent rf cavities restoring longitudinal momentum necessarymore » to maintain stable orbit of the beam. COSY INFINITY is utilized to simulate the theory at first order. The motion of particles around a hyperbolic fixed point is tracked. Comparison is made between the EPIC cooling channel and standard ionization cooling effects. Cooling effects are measured, after including stochastic effects, for both a single particle and a distribution of particles.« less

  7. Ion-beam mixed ultra-thin cobalt suicide (CoSi2) films by cobalt sputtering and rapid thermal annealing

    NASA Astrophysics Data System (ADS)

    Kal, S.; Kasko, I.; Ryssel, H.

    1995-10-01

    The influence of ion-beam mixing on ultra-thin cobalt silicide (CoSi2) formation was investigated by characterizing the ion-beam mixed and unmixed CoSi2 films. A Ge+ ion-implantation through the Co film prior to silicidation causes an interface mixing of the cobalt film with the silicon substrate and results in improved silicide-to-silicon interface roughness. Rapid thermal annealing was used to form Ge+ ion mixed and unmixed thin CoSi2 layer from 10 nm sputter deposited Co film. The silicide films were characterized by secondary neutral mass spectroscopy, x-ray diffraction, tunneling electron microscopy (TEM), Rutherford backscattering, and sheet resistance measurements. The experi-mental results indicate that the final rapid thermal annealing temperature should not exceed 800°C for thin (<50 nm) CoSi2 preparation. A comparison of the plan-view and cross-section TEM micrographs of the ion-beam mixed and unmixed CoSi2 films reveals that Ge+ ion mixing (45 keV, 1 × 1015 cm-2) produces homogeneous silicide with smooth silicide-to-silicon interface.

  8. Recent results from the NN-interaction studies with polarized beams and targets at ANKE-COSY

    NASA Astrophysics Data System (ADS)

    Dymov, Sergey

    2016-02-01

    Adding to the nucleon-nucleon scattering database is one of the major priorities of the ANKE collaboration. Such data are necessary ingredients, not only for the understanding of nuclear forces, but also for the description of meson production and other nuclear reactions at intermediate energies. By measuring the cross section, deuteron analysing powers, and spin-correlation parameters in the dp → {pp}sn reaction, where {pp}s represents the 1S0 state, information has been obtained on small-angle neutron-proton spin-flip charge-exchange amplitudes. The measurements of pp elastic scattering by the COSY-EDDA have had a major impact on the partial wave analysis of this reaction above 1 GeV. However, these experiments only extended over the central region of c.m. angles, 300 < θcm < 1500, that has left major ambiguities in the phase shift analysis by the SAID group. In contrast, the small angle region is accessible at ANKE-COSY, that allowed measurement of the differential cross section and the analysing power at 50 < θcm < 300 in the 0.8 — 2.8 GeV energy range. The data on the pn elastic scattering are much more scarce than those of pp, especially in the region above 1.15 GeV. The study of the dp → {pp}s n reaction provides the information about the pn elastic scattering at large angles. The small angle scattering was studied with the polarized proton COSY beam and an unpolarised deuterium gas target. The detection the spectator proton in the ANKE vertex silicon detector allowed to use the deuterium target as an effective neutron one. The analysing powers of the process were obtained at six beam energies from 0.8 to 2.4 GeV.

  9. Electronic and magnetic properties of magnetoelectric compound Ca2CoSi2O7: An ab initio study

    NASA Astrophysics Data System (ADS)

    Chakraborty, Jayita

    2018-05-01

    The detailed first principle density functional theory calculations are carried out to investigate the electronic and magnetic properties of magnetoelectric compound Ca2CoSi2O7. The magnetic properties of this system are analyzed by calculating various hopping integrals as well as exchange interactions and deriving the relevant spin Hamiltonian. The dominant exchange path is visualized with Wannier functions plotting. Only intra planer nearest neighbor exchange interaction is strong in this system. The magnetocrystalline anisotropy is calculated for this system, and the results of the calculation reveal that the spin quantization axis lies in the ab plane.

  10. The polarized atomic-beam target for the EDDA experiment and the time-reversal invariance test at COSY

    NASA Astrophysics Data System (ADS)

    Eversheim, P. D.; Altmeier, M.; Felden, O.

    1997-02-01

    For the the EDDA experiment, which was set up to measure the p¯-p¯ excitation function during the acceleration ramp of the cooler synchrotron COSY at Jülich, a polarized atomic-beam target was designed regarding the restrictions imposed by the geometry of the EDDA detector. Later, when the time-reversal invariance experiment is to be performed, the EDDA detector will serve as efficient internal polarimeter and the source has to deliver tensor polarized deuterons. The modular design of this polarized atomic-beam target that allows to meet these conditions will be discussed in comparison to other existing polarized atomic-beam targets.

  11. In situ transmission electron microscopy study on the epitaxial growth of CoSi2 on Si(111) at temperatures below 150 C

    NASA Technical Reports Server (NTRS)

    Nieh, C. W.; Lin, T. L.

    1989-01-01

    This paper reports an in situ transmission electron microscopy study on the epitaxial growth of CoSi2 on Si(111) from a 10-nm-thick amorphous mixture of Co and Si in the ratio 1:2, which was formed by codeposition of Co and Si near room temperature. Nuclei of CoSi2 are observed in the as-deposited film. These nuclei are epitaxial and extend through the whole film thickness. Upon annealing, these columnar epitaxial CoSi2 grains grow laterally at temperatures as low as 50 C. The kinetics of this lateral epitaxial growth was studied at temperatures between 50 and 150 C. The activation energy of the growth process is 0.8 + or - 0.1 eV.

  12. Structural and magnetic studies of half-metallic Heusler alloy Cr2CoSi nanoparticle synthesized by mechanical-alloying method

    NASA Astrophysics Data System (ADS)

    Saravanan, G.; Asvini, V.; Kalaiezhily, R. K.; Ravichandran, K.

    2018-05-01

    Heusler Alloy based Cr2CoSi nanoparticles were synthesized by using ball milling. X-ray diffractions studies were used to characterize the crystal structure of Cr2CoSi nanoparticles and magnetic properties were studied using VSM. XRD data analysis confirms the Heusler alloy phase showing the L21 structure. Magnetic properties are measured for synthesized samples having coercivity Hc = 389 Oe, with high saturation magnetization value Ms = 8.64 emu/g and remenance value Mr = 2.93 emu/g. Synthesized Heusler alloy Cr2CoSi nanoparticles can be potential materials for use in Spin polarized based spin sensors, spin devices, magnetic sensors and transducer applications.

  13. Resveratrol tetramer of hopeaphenol isolated from Shorea johorensis (Dipterocarpaceae)

    NASA Astrophysics Data System (ADS)

    Aisha, Farra; Din, Laily B.; Yaacob, W. A.

    2014-09-01

    Hopeaphenol (1) as a resveratrol tetramer was isolated from the bark of Shorea johorensis collected from Imbak Canyon, Sabah, Malaysia. The structure of this compound was determined by the spectroscopic evidences using 1H- and 13C-NMR assigned with HSQC, HMBC, 1H-1H COSY and 1H-1H NOESY spectra, mass spectrum, and by comparison with reported data.

  14. Gigantic magnetoelectric effect caused by magnetic-field-induced canted antiferromagnetic-paramagnetic transition in quasi-two-dimensional Ca2CoSi2O7 crystal

    NASA Astrophysics Data System (ADS)

    Akaki, M.; Tozawa, J.; Akahoshi, D.; Kuwahara, H.

    2009-05-01

    We have investigated the magnetic and dielectric properties of Ca2CoSi2O7 crystal. The dielectricity and magnetism of Ca2CoSi2O7 are strongly coupled below a canted antiferromagnetic transition temperature (TN). Magnetic fields induce electric polarization below TN. Interestingly, the magnetic-field-induced electric polarization is detected even without poling electric fields. Below TN, a canted antiferromagnetic-paramagnetic transition is induced by magnetic fields. The large magnetocapacitance is observed around TN. The origin of the large magnetocapacitance is due to the magnetic-field-induced the canted antiferromagnetic-paramagnetic transition.

  15. Analysis of closed orbit deviations for a first direct deuteron electric dipole moment measurement at the cooler synchrotron COSY

    NASA Astrophysics Data System (ADS)

    Schmidt, V.; Lehrach, A.

    2017-07-01

    The Jülich Electric Dipole moment Investigations (JEDI) collaboration in Julich is preparing a direct EDM measurement of protons and deuterons first at the storage ring COSY (COoler SYnchrotron) and later at a dedicated storage ring. Ensuring a precise measurement, various beam and spin manipulating effects have to be considered and investigated. A distortion of the closed orbit is one of the major sources for systematic uncertainties. Therefore misalignments of magnets and residual power supply oscillations are simulated using the MAD-X code in order to analyse their effect on the orbit. The underlying model for all simulations includes the dipoles, quadrupoles and sextupoles at COSY as well as the corrector magnets and BPMs (Beam Position Monitors). Since most sextupoles are only used during beam extraction, the sextupole strengths are set to zero resulting in a linear machine. The optics is adjusted in a way that the dispersion is zero in the straight sections. The closed orbit studies are performed for deuterons with a momentum of 970 MeV/c.

  16. Recrystallization in Si upon ion irradiation at room temperature in Co/Si(111) thin film systems

    NASA Astrophysics Data System (ADS)

    Banu, Nasrin; Satpati, B.; Dev, B. N.

    2018-04-01

    After several decades of research it was concluded that for a constant flux recrystallization in Si upon ion irradiation is possible only at high temperature. At low temperature or at room temperature only amorphization can take place. However we have observed recrystallization in Si upon ion irradiation at room temperature in a Co/Si thin film system. The Co/Si sample was prepared by deposition of 25 nm Co on clean Si(111) substrate. An oxide layer (˜ 2nm) of cobalt at the top of the film due to air exposure. The ion irradiation was done at room temperature under high vacuum with 1MeV Si+ ion with low beam current < 400 nA. Earlier we have shown similar ion induced recrystallization in Si(100) substrate which had a sandwich Si/Ni/Si structure. This system had an epitaxial buffer Si layer on Si substrate. This study also shows that the phenomenon is independent of substrate orientation and buffer layer. We have used transmission electron microscopy (TEM) to study the recrystallization behavior.

  17. The (2×2) reconstructions on the surface of cobalt silicides: Atomic configuration at the annealed Co/Si(111) interface

    NASA Astrophysics Data System (ADS)

    Kotlyar, V. G.; Alekseev, A. A.; Olyanich, D. A.; Utas, T. V.; Zotov, A. V.; Saranin, A. A.

    2017-08-01

    We have used scanning tunneling microscopy (STM) and ab initio total-energy calculations to characterize surface and interfacial structure of Co-Si(111) system. It has been found experimentally that two different types of the (2×2) surface structures occur. The coexistence of two phases is demonstrated by the example of STM image of the surface formed at the early stages of cobalt silicide formation under moderate annealing temperatures (500 °C). The measured height difference between the adjacent (2×2) reconstructed patches equal to about 1.0 Å (as determined from the filled-state STM images). In addition, the shift of the atomic rows by half of the row spacing is observed. Two adatom models of the (2×2) surface structures are developed. According to our data, these structures are assigned to CaF2-type CoSi2 and CsCl-type CoSi with a (2×2) array of Si adatoms on their surfaces. If the latter is the case, it has а coherent double interface CoSi/CoSi2/Si(111) with a two-layer CoSi2. Both of these interfaces are characterized by the eightfold cobalt coordination and incorporate a grown-in stacking fault.

  18. Development of a core set of quality indicators for paediatric primary care practices in Europe, COSI-PPC-EU.

    PubMed

    Ewald, Dominik A; Huss, Gottfried; Auras, Silke; Caceres, Juan Ruiz-Canela; Hadjipanayis, Adamos; Geraedts, Max

    2018-06-01

    Paediatric ambulatory healthcare systems in Europe are, because of historical reasons, diverse and show strikingly different outcomes. All across Europe, the benchmarking of structures, processes and outcomes could reveal opportunities for improving Paediatric Primary Care (PPC). The aim of this study was to develop a set of Quality Indicators (QIs) to assess and monitor PPC in Europe. In a three-step process, we used the available external evidence and European expert consensus in a modified RAND/UCLA Appropriateness Method (RAM) to develop an indicator set. (1) A broad literature and online research of published QI and guidelines yielded an inventory of 1516 QI. (2) A collaborative panel of paediatric senior experts from the European Academy of Paediatrics (EAP) and the European Confederation of Primary Care Paediatricians (ECPCP) from 15 European countries participated in a first consensus process to reduce the initial indicator inventory by eliminating not PPC-focused indicators and duplicates. (3) In a second consensus process, the panel rated the QI regarding validity and feasibility. The final QI set "COSI-PPC-EU" consists of 42 indicators in five categories of PPC: (A) health promotion/prevention/screening (13 QI), (B) acute care (9 QI), (C) chronic care (8 QI), (D) practice management (3 QI) and (E) patient safety (9 QI). COSI-PPC-EU represents a consented set of a limited number of valid quality indicators for the application in paediatric primary care in different healthcare systems throughout Europe. What is Known: • Paediatric ambulatory healthcare systems in Europe are diverse and show strikingly different outcomes. • There are known gaps in quality performance measures of paediatric primary care in Europe. Pre-existing sets of quality indicators are predominantly limited to national populations, specific diseases and hospital care. What is New: • A set of 42 quality indicators for primary paediatric care in Europe was developed in a multi

  19. Measurement of the branching ratio of a rare decay {eta}{yields}{pi}{sup 0}{gamma}{gamma} with WASA-at-COSY

    SciTech Connect

    Lalwani, Kavita

    2011-10-24

    In this paper we present the preliminary results on the measurement of the branching ratio of a rare decay {eta}{yields}{pi}{sup 0}{gamma}{gamma} with the WASA Detector at COSY. We have used a sample of 10{sup 7}{eta} mesons produced at the COSY ring using the pd{yields}{sup 3}He{eta} reaction close to threshold. We detail the intricate extraction of the signal, which has about 360{+-}70(stat){eta}{yields}{pi}{sup 0}{gamma}{gamma} events, from the overwhelming background channels for example {eta}{yields}3{pi}{sup 0}, pd{yields}{sup 3}He 3{pi}{sup 0} and pd{yields}{sup 3}He 2{pi}{sup 0}.

  20. Isovalent substitutes play in different ways: Effects of isovalent substitution on the thermoelectric properties of CoSi0.98B0.02

    DOE PAGES

    Sun, Hui; Lu, Xu; Morelli, Donald T.

    2016-07-21

    Boron-added CoSi, CoSi 0.98B 0.02, possesses a very high thermoelectric power factor of 60 μW cm -1 K -2 at room temperature, which is among the highest power factors that have ever been reported for near-room-temperature thermoelectric applications. Since the electrical properties of this material have been tuned properly, isovalent substitution for its host atoms are intentionally employed to reduce the lattice thermal conductivity while maintaining the electronic properties unchanged. In our previous work, the effect of Rh substitution for Co atoms on the thermoelectric properties of CoSi 0.98B 0.02 has been studied. Here we present a study of themore » substitution of Ge for Si atoms in this compound. Even though Ge and Rh are isovalent with their corresponding host atoms, they play different roles in determining the electrical and thermal transport properties. Through the evaluation of the lattice thermal conductivity by the Debye approximation and the comparison between the high-temperature Seebeck coefficients, we propose that Rh substitution leads to a further overlapping of the conduction and the valence bands while Ge substitution only shifts the Fermi level upward into the conduction band. Lastly, our results show that the influence of isovalent substitution on the electronic structure cannot be ignored when the alloying method is used to improve thermoelectric properties.« less

  1. Isovalent substitutes play in different ways: Effects of isovalent substitution on the thermoelectric properties of CoSi0.98B0.02

    SciTech Connect

    Sun, Hui; Lu, Xu; Morelli, Donald T.

    Boron-added CoSi, CoSi 0.98B 0.02, possesses a very high thermoelectric power factor of 60 μW cm -1 K -2 at room temperature, which is among the highest power factors that have ever been reported for near-room-temperature thermoelectric applications. Since the electrical properties of this material have been tuned properly, isovalent substitution for its host atoms are intentionally employed to reduce the lattice thermal conductivity while maintaining the electronic properties unchanged. In our previous work, the effect of Rh substitution for Co atoms on the thermoelectric properties of CoSi 0.98B 0.02 has been studied. Here we present a study of themore » substitution of Ge for Si atoms in this compound. Even though Ge and Rh are isovalent with their corresponding host atoms, they play different roles in determining the electrical and thermal transport properties. Through the evaluation of the lattice thermal conductivity by the Debye approximation and the comparison between the high-temperature Seebeck coefficients, we propose that Rh substitution leads to a further overlapping of the conduction and the valence bands while Ge substitution only shifts the Fermi level upward into the conduction band. Lastly, our results show that the influence of isovalent substitution on the electronic structure cannot be ignored when the alloying method is used to improve thermoelectric properties.« less

  2. Effect of CoSi2 buffer layer on structure and magnetic properties of Co films grown on Si (001) substrate

    NASA Astrophysics Data System (ADS)

    Hu, Bo; He, Wei; Ye, Jun; Tang, Jin; Syed Sheraz, Ahmad; Zhang, Xiang-Qun; Cheng, Zhao-Hua

    2015-01-01

    Buffer layer provides an opportunity to enhance the quality of ultrathin magnetic films. In this paper, Co films with different thickness of CoSi2 buffer layers were grown on Si (001) substrates. In order to investigate morphology, structure, and magnetic properties of films, scanning tunneling microscope (STM), low energy electron diffraction (LEED), high resolution transmission electron microscopy (HRTEM), and surface magneto-optical Kerr effect (SMOKE) were used. The results show that the crystal quality and magnetic anisotropies of the Co films are strongly affected by the thickness of CoSi2 buffer layers. Few CoSi2 monolayers can prevent the interdiffusion of Si substrate and Co film and enhance the Co film quality. Furthermore, the in-plane magnetic anisotropy of Co film with optimal buffer layer shows four-fold symmetry and exhibits the two-jumps of magnetization reversal process, which is the typical phenomenon in cubic (001) films. Project supported by the National Basic Research Program of China (Grant Nos. 2011CB921801 and 2012CB933102), the National Natural Science Foundation of China (Grant Nos. 11374350, 11034004, 11274361, and 11274033), and the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20131102130005).

  3. Effect of film thickness on soft magnetic behavior of Fe2CoSi Heusler alloy for spin transfer torque device applications

    NASA Astrophysics Data System (ADS)

    Asvini, V.; Saravanan, G.; Kalaiezhily, R. K.; Raja, M. Manivel; Ravichandran, K.

    2018-04-01

    Fe2CoSi based Heusler alloy thin films were deposited on Si (111) wafer (substrate) of varying thickness using ultra high vacuum DC magnetron sputtering. The structural behavior was observed and found to be hold the L21 structure. The deposited thin films were characterized magnetic properties using vibrating sample magnetometer; the result shows a very high saturated magnetization (Ms), lowest coercivity (Hc), high curie transition temperature (Tc) and low hysteresis loss. Thin film thickness of 75 nm Fe2CoSi sample maintained at substrate temperature 450°C shows the lowest coercivity (Hc=7 Oe). In general, Fe2CoSi Heusler alloys curie transition temperature is very high, due to strong exchange interaction between the Fe and Co atoms. The substrate temperature was kept constant at 450°C for varying thickness (e.g. 5, 20, 50, 75 and 100 nm) of thin film sample. The 75 nm thickness thin film sample shows well crystallanity and good magnetic properties, further squareness ratio in B-H loop increases with the increase in film thickness.

  4. Sulfated and pyruvylated disaccharide alditols obtained from a red seaweed galactan: ESIMS and NMR approaches.

    PubMed

    Gonçalves, Alan G; Ducatti, Diogo R B; Duarte, M Eugênia R; Noseda, Miguel D

    2002-11-29

    The water-soluble acid agaran isolated from Acanthophora spicifera (Rhodophyta) was submitted to alkaline treatment for the complete cyclization of alpha-L-Galp 6-sulfate to 3,6-An-alpha-L-Galp units. The modified agaran was then partially depolymerized using partial reductive hydrolysis. The resulting oligosaccharide mixture was fractionated by adsorption and ion-exchange chromatography. Fractions were purified by gel-filtration chromatography and studied by ESIMS and NMR spectroscopy, including 1D 1H, 13C, DEPT and 2D 1H, 1H COSY, TOCSY and 1H, 13C HMQC procedures. The following neutral, pyruvylated, sulfated and sulfated/pyruvylated disaccharide alditols were obtained: beta-D-Galp-(1-->4)-3,6-An-L-GalOH; 4,6-O-(1-carboxyethylidene)-beta-D-Galp-(1-->4)-3,6-An-L-GalOH; beta-D-Galp 2-sulfate-(1-->4)-3,6-An-L-GalOH and 4,6-O-(1-carboxyethylidene)-beta-D-Galp 2-sulfate-(1-->4)-3,6-An-L-GalOH.

  5. Chaetopyranin, a benzaldehyde derivative, and other related metabolites from Chaetomium globosum, an endophytic fungus derived from the marine red alga Polysiphonia urceolata.

    PubMed

    Wang, Song; Li, Xiao-Ming; Teuscher, Franka; Li, Dong-Li; Diesel, Arnulf; Ebel, Rainer; Proksch, Peter; Wang, Bin-Gui

    2006-11-01

    Cultivation of the endophytic fungus Chaetomium globosum, which was isolated from the inner tissue of the marine red alga Polysiphonia urceolata, resulted in the isolation of chaetopyranin (1), a new benzaldehyde secondary metabolite. Ten known compounds were also isolated, including two benzaldehyde congeners, 2-(2',3-epoxy-1',3'-heptadienyl)-6-hydroxy-5-(3-methyl-2-butenyl)benzaldehyde (2) and isotetrahydroauroglaucin (3), two anthraquinone derivatives, erythroglaucin (4) and parietin (5), five asperentin derivatives including asperentin (6, also known as cladosporin), 5'-hydroxy-asperentin-8-methylether (7), asperentin-8-methyl ether (8), 4'-hydroxyasperentin (9), and 5'-hydroxyasperentin (10), and the prenylated diketopiperazine congener neoechinulin A (11). The structures of these compounds were determined on the basis of their spectroscopic data analysis (1H, 13C, 1H-1H COSY, HMQC, and HMBC NMR, as well as low- and high-resolution mass experiments). To our knowledge, compound 1 represents the first example of a 2H-benzopyran derivative of marine algal-derived fungi as well as of the fungal genus Chaetomium. Each isolate was tested for its DPPH (1,1-diphenyl-2-picrylhydrazyl) radical-scavenging property. Compounds 1-4 were found to have moderate activity. Chaetopyranin (1) also exhibited moderate to weak cytotoxic activity toward several tumor cell lines.

  6. Induction of quinone reductase (QR) by withanolides isolated from Physalis angulata L. var. villosa Bonati (Solanaceae).

    PubMed

    Ding, Hui; Hu, Zhijuan; Yu, Liyan; Ma, Zhongjun; Ma, Xiaoqiong; Chen, Zhe; Wang, Dan; Zhao, Xiaofeng

    2014-08-01

    In the present study, the EtOAc extract of the persistent calyx of Physalis angulata L. var. villosa Bonati (PA) was tested for its potential quinone reductase (QR) inducing activity with glutathione (GSH) as the substrate using an UPLC-ESI-MS method. The result revealed that the PA had electrophiles that could induce quinone reductase (QR) activity, which might be attributed to the modification of the highly reactive cysteine residues in Keap1. Herein, three new withanolides, compounds 3, 6 and 7, together with four known withanolides, compounds 1, 2, 4 and 5 were isolated from PA extract. Their structures were determined by spectroscopic techniques, including (1)H-, (13)C NMR (DEPT), and 2D-NMR (HMBC, HMQC, (1)H, (1)H-COSY, NOESY) experiments, as well as by HR-MS. All the seven compounds were tested for their QR induction activities towards mouse hepa 1c1c7 cells. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Unraveling the active hypoglycemic agent trigonelline in Balanites aegyptiaca date fruit using metabolite fingerprinting by NMR.

    PubMed

    Farag, Mohamed A; Porzel, Andrea; Wessjohann, Ludger A

    2015-11-10

    Trigonelline (3-carboxy-1-methyl pyridinium) was identified as a relevant bioactivity and taste imparting component in Balanites aegyptiaca fruit, using (1)H NMR of crude extracts without any fractionation or isolation step. The structural integrity of trigonelline was established within the extract matrix via(1)H NMR, (1)H-(1)H COSY, HMQC and HMBC and by comparison with authentic standard. A quantitative (1)H NMR method (qHNMR) was used to determine trigonelline concentrations in the peel and pulp of B. aegyptiaca fruit of 8 and 13mgg(-1), respectively. Trigonelline so far has not been reported from B. aegyptiaca or its genus as it easily escapes LC-MS based detection. Its discovery provides novel insight into the balanite fruits antidiabetic properties as the compound is known for a pronounced hypoglycemic effect. In addition, it is likely to impart the perceptible bitter taste portion to balanites sweet bitter taste. UPLC-MS of the crude extract additionally revealed the fruit flavonoid pattern showing quercetin/isorhamnetin flavonol conjugates in addition to epicatechin, the latter being present at much lower levels. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Structure elucidation of a bioactive polysaccharide from fruiting bodies of Hericium erinaceus in different maturation stages.

    PubMed

    Li, Qiao-Zhen; Wu, Di; Zhou, Shuai; Liu, Yan-Fang; Li, Zheng-Peng; Feng, Jie; Yang, Yan

    2016-06-25

    HPB-3, a heteropolysaccharide, with a mean molecular weight of 1.5×10(4)Da, was obtained from the maturating-stage IV, V and VI fruiting body of Hericium erinaceus, exhibited higher macrophages stimulation activities, was able to upregulate the functional events mediated by activated macrophages, such as production of nitric oxide (NO). Monosaccharide composition analysis showed that HPB-3 comprised l-fucose, d-galactose and d-glucose in the ratio of 5.2:23.9:1. Its chemical structure was characterized by sugar and methylation analysis, along with (1)H and (13)C NMR spectroscopy, including (1)H-(1)H COSY, TOCSY, NOESY, HMQC and HMBC experiments. The results indicated that HPB-3 contained a-(1/6)-linked galactopyranosyl backbone, partially with a side chain composed of α-l-fucopyranose at the O-2 position. The predicted primary structure of the polysaccharide was established as below. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. BIG KARL and COSY: Examples for high performance magnet design taught by {open_quotes}Papa Klaus{close_quotes}

    SciTech Connect

    Bechtstedt, U.; Hacker, U.; Maier, R.

    1995-02-01

    The past decades have seen a tremendous development in nuclear, middle, and high energy physics. This advance was in a great part promoted by the availability of newer and more powerful instruments. Over time, these instruments grew in size as well as in sophistication and precision. Nearly all these devices had one fundamental thing in common - magnetic fields produced with currents and iron. The precision demanded by the new experiments and machines did bring the magnet technology to new frontiers requiring the utmost in the accuracy of magnetic fields. The complex properties of the iron challenged innumerable physicists inmore » the attempt to force the magnetic fields into the desired shape. Experience and analytical insight were the pillars for coping with those problems and only few mastered the skills and were in addition able to communicate their intricate knowledge. It was a fortuitous situation that the authors got to know Klaus Halbach who belonged to those few and who shared his knowledge contributing thus largely to the successful completion of two large instruments that were built at the Forschungszentrum Juelich, KFA, for nuclear and middle energy physics. In one case the efforts went to the large spectrometer named BIG KARL whose design phase started in the early 70`s. In the second case the work started in the early 80`s with the task to build a high precision 2.5 GeV proton accelerator for cooled stored and extracted beams known as COSY-Juelich.« less

  10. Resistance Switching Memory Characteristics of Si/CaF2/CdF2 Quantum-Well Structures Grown on Metal (CoSi2) Layer

    NASA Astrophysics Data System (ADS)

    Denda, Junya; Uryu, Kazuya; Watanabe, Masahiro

    2013-04-01

    A novel scheme of resistance switching random access memory (ReRAM) devices fabricated using Si/CaF2/CdF2/CaF2/Si quantum-well structures grown on metal CoSi2 layer formed on a Si substrate has been proposed, and embryonic write/erase memory operation has been demonstrated at room temperature. It has been found that the oxide-mediated epitaxy (OME) technique for forming the CoSi2 layer on Si dramatically improves the stability and reproducibility of the current-voltage (I-V) curve. This technology involves 10-nm-thick Co layer deposition on a protective oxide prepared by boiling in a peroxide-based solution followed by annealing at 550 °C for 30 min for silicidation in ultrahigh vacuum. A switching voltage of lower than 1 V, a peak current density of 32 kA/cm2, and an ON/OFF ratio of 10 have been observed for the sample with the thickness sequence of 0.9/0.9/2.5/0.9/5.0 nm for the respective layers in the Si/CaF2/CdF2/CaF2/Si structure. Results of surface morphology analysis suggest that the grain size of crystal islands with flat surfaces strongly affects the quality of device characteristics.

  11. Image cross-correlation using COSI-Corr: A versatile technique to monitor and quantity surface deformation in space and time

    NASA Astrophysics Data System (ADS)

    Leprince, S.; Ayoub, F.; Avouac, J.

    2011-12-01

    We have developed a suite of algorithms for precise Co-registration of Optically Sensed Images and Correlation (COSI-Corr) which were implemented in a software package first released to the academic community in 2007. Its capability for accurate surface deformation measurement has proved useful for a wide variety of applications. We present the fundamental principles of COSI-Corr, which are the key ingredients to achieve sub-pixel registration and sub-pixel measurement accuracy, and we show how they can be applied to various types of images to extract 2D, 3D, or even 4D deformation fields of a given surface. Examples are drawn from recent collaborative studies and include: (1) The study of the Icelandic Krafla rifting crisis that occurred from 1975 to 1984 where we used a combination of archived airborne photographs, declassified spy satellite imagery, and modern satellite acquisitions to propose a detailed 2D displacement field of the ground; (2) The estimation of glacial velocities from fast New Zealand glaciers using successive ASTER acquisitions; (3) The derivation of sand dunes migration rates; (4) The estimation of ocean swell velocity taking advantage of the short time delay between the acquisition of different spectral bands on the SPOT 5 satellite; (5) The derivation of the full 3D ground displacement field induced by the 2010 Mw 7.2 El Mayor-Cucapah Earthquake, as recorded from pre- and post-event lidar acquisitions; (6) And, the estimation of 2D in plane deformation of mechanical samples under stress in the lab. Finally, we conclude by highlighting the potential future and implication of applying such correlation techniques on a large scale to provide global monitoring of our environment.

  12. Structural stability and electronic behaviors of Co1-xOsxSi and macroscopic magnetic susceptibilities of CoSi and OsSi: GGA-PBEsol, GW-approximation and QTAIM investigations

    NASA Astrophysics Data System (ADS)

    Bouafia, H.; Sahli, B.; Timaoui, M. A.; Djebour, B.; Hiadsi, S.; Abidri, B.

    2018-02-01

    The present work represents a theoretical investigation based on FP-(L)APW + lo method of structural properties, mechanical stability and electronic properties of Co1-xOsxSi as well as the macroscopic magnetic susceptibilities of CoSi and OsSi. The structural properties such as cell parameter, bulk modulus, internal parameters and total energy of non-magnetic NM, ferromagnetic FM and antiferromagnetic AFM phases were predicted by GGA-PBEsol semilocal functional. The obtained results for CoSi and OsSi are in good agreement with those found previously. The spin, orbital and total macroscopic magnetic susceptibilities of CoSi and OsSi have been estimated and confirmed that these compounds are diamagnetic. The total energy of the ferromagnetic phase of Co1-xOsxSi (with x = 0.25, 0.5 and 0.75) is the lowest indicating that they are ferromagnetic materials. The generalized stability criteria indicate that Co1-xOsxSi maintain their mechanical stabilities under a hydrostatic pressure less than 10 GPa. The electronic properties calculated by GW-approximation indicate that CoSi and Co1-xOsxSi (with x = 0.25, 0.50 and 0.75) are semimetals whereas OsSi is a semiconductor with a pseudo-direct band-gap. The topological analysis by QTAIM and the charge density plots indicate that the strong covalent character is predominant for Cosbnd Si, Ossbnd Si and Cosbnd Os bonds.

  13. Stereoselective synthesis, spectral and antimicrobial studies of some cyanoacetyl hydrazones of 3-alkyl-2,6-diarylpiperidin-4-ones

    NASA Astrophysics Data System (ADS)

    Velayutham Pillai, M.; Rajeswari, K.; Vidhyasagar, T.

    2014-11-01

    A series of novel cyanoacetyl hydrazones of 3-alkyl-2,6-diarylpiperidin-4-ones were synthesized stereoselectively and characterized by IR, Mass, 1H NMR, 13C NMR, 1H-1H COSY and 1H-13C COSY spectra. The stereochemistry of the synthesized compounds was established using NMR spectra. Antimicrobial screening of the synthesized compounds revealed their antibacterial and antifungal potencies. Growth inhibition of Enterobacter Aerogenes by compound 15 was found to be superior to the standard drug.

  14. A dimeric ArC2 compound from Peperomia pellucida.

    PubMed

    Bayma, J D; Arruda, M S; Müller, A H; Arruda, A C; Canto, W C

    2000-12-01

    Pellucidin A, a novel dimeric ArC2 compound, together with dill-apiol have been isolated from the aerial parts of Peperomia pellucida. The structure of pellucidin A was established by 1D and 2D NMR spectroscopy (1H-1H COSY; 1H-13C COSY; DEPT; NOESY and double irradiation) and other spectroscopic techniques. The biogenesis of pellucidin A is also briefly discussed.

  15. Development of a Standardized Methodology for the Use of COSI-Corr Sub-Pixel Image Correlation to Determine Surface Deformation Patterns in Large Magnitude Earthquakes.

    NASA Astrophysics Data System (ADS)

    Milliner, C. W. D.; Dolan, J. F.; Hollingsworth, J.; Leprince, S.; Ayoub, F.

    2014-12-01

    Coseismic surface deformation is typically measured in the field by geologists and with a range of geophysical methods such as InSAR, LiDAR and GPS. Current methods, however, either fail to capture the near-field coseismic surface deformation pattern where vital information is needed, or lack pre-event data. We develop a standardized and reproducible methodology to fully constrain the surface, near-field, coseismic deformation pattern in high resolution using aerial photography. We apply our methodology using the program COSI-corr to successfully cross-correlate pairs of aerial, optical imagery before and after the 1992, Mw 7.3 Landers and 1999, Mw 7.1 Hector Mine earthquakes. This technique allows measurement of the coseismic slip distribution and magnitude and width of off-fault deformation with sub-pixel precision. This technique can be applied in a cost effective manner for recent and historic earthquakes using archive aerial imagery. We also use synthetic tests to constrain and correct for the bias imposed on the result due to use of a sliding window during correlation. Correcting for artificial smearing of the tectonic signal allows us to robustly measure the fault zone width along a surface rupture. Furthermore, the synthetic tests have constrained for the first time the measurement precision and accuracy of estimated fault displacements and fault-zone width. Our methodology provides the unique ability to robustly understand the kinematics of surface faulting while at the same time accounting for both off-fault deformation and measurement biases that typically complicates such data. For both earthquakes we find that our displacement measurements derived from cross-correlation are systematically larger than the field displacement measurements, indicating the presence of off-fault deformation. We show that the Landers and Hector Mine earthquake accommodated 46% and 38% of displacement away from the main primary rupture as off-fault deformation, over a mean

  16. Surface rupture and slip variation induced by the 2010 El Mayor-Cucapah earthquake, Baja California, quantified using COSI-Corr analysis on pre- and post-earthquake LiDAR acquisitions

    NASA Astrophysics Data System (ADS)

    Leprince, S.; Hudnut, K. W.; Akciz, S. O.; Hinojosa-Corona, A.; Fletcher, J. M.

    2011-12-01

    One-hundred and three years after the publication of the Lawson report on the Great 1906 earthquake, accurate documentation of surface deformation along the entire length of an earthquake is still challenging. Analysis of pre- and post-earthquake topographic data provides an opportunity to deliver the full 3D displacement field of the ground's surface. However, direct differencing of a pre- and post-earthquake digital topography model (DEM) generally leads to biased estimation of the vertical component of the deformation. Indeed, if the earthquake also produced significant horizontal motion, or if the pre- and post-earthquake DEM acquisitions exhibit non-negligible horizontal mis-registration, then the vertical offset measured by direct differencing will be biased by the local topography gradient. To overcome this limitation, we use the COSI-Corr sub-pixel correlation algorithm to estimate the relative horizontal offset between the pre- and post- 2010 El Mayor - Cucapah earthquake high resolution LiDAR acquisitions. Compensating for the horizontal offset between the two LiDAR acquisitions allows us to estimate unbiased measurements of the vertical component of the surface fault rupture induced by the El Mayor-Cucapah earthquake. We will also show the limitations of the available data set, such as aircraft jitter artifacts, which impaired accurate measurements of the horizontal component of the surface deformation. This analysis shows an unprecedented view of the complete vertical slip component of the rupture induced by the Mw 7.2 2010 El Mayor-Cucapah earthquake, sampled at every 5 m, over a length of about 100 km, and with a vertical accuracy of a few centimeters. Using sampling bins as narrow as 150 m and 1.5 km long, variations in the vertical component of an oblique slip earthquake are presented, with breaks along multiple fault-strands showing opposite dip directions and diffuse boundaries. With the availability of high precision pre- and post-earthquake data

  17. Improving the resolution in proton-detected through-space heteronuclear multiple quantum correlation NMR spectroscopy.

    PubMed

    Shen, Ming; Trébosc, J; Lafon, O; Pourpoint, F; Hu, Bingwen; Chen, Qun; Amoureux, J-P

    2014-08-01

    Connectivities and proximities between protons and low-gamma nuclei can be probed in solid-state NMR spectroscopy using two-dimensional (2D) proton-detected heteronuclear correlation, through Heteronuclear Multiple Quantum Correlation (HMQC) pulse sequence. The indirect detection via protons dramatically enhances the sensitivity. However, the spectra are often broadened along the indirect F1 dimension by the decay of heteronuclear multiple-quantum coherences under the strong (1)H-(1)H dipolar couplings. This work presents a systematic comparison of the performances of various decoupling schemes during the indirect t1 evolution period of dipolar-mediated HMQC (D-HMQC) experiment. We demonstrate that (1)H-(1)H dipolar decoupling sequences during t1, such as symmetry-based schemes, phase-modulated Lee-Goldburg (PMLG) and Decoupling Using Mind-Boggling Optimization (DUMBO), provide better resolution than continuous wave (1)H irradiation. We also report that high resolution requires the preservation of (1)H isotropic chemical shifts during the decoupling sequences. When observing indirectly broad spectra presenting numerous spinning sidebands, the D-HMQC sequence must be fully rotor-synchronized owing to the rotor-synchronized indirect sampling and dipolar recoupling sequence employed. In this case, we propose a solution to reduce artefact sidebands caused by the modulation of window delays before and after the decoupling application during the t1 period. Moreover, we show that (1)H-(1)H dipolar decoupling sequence using Smooth Amplitude Modulation (SAM) minimizes the t1-noise. The performances of the various decoupling schemes are assessed via numerical simulations and compared to 2D (1)H-{(13)C} D-HMQC experiments on [U-(13)C]-L-histidine⋅HCl⋅H2O at various magnetic fields and Magic Angle spinning (MAS) frequencies. Great resolution and sensitivity enhancements resulting from decoupling during t1 period enable the detection of heteronuclear correlation between

  18. Cordioxime: a new dioxime gamma-lactam from Cordia platythyrsa.

    PubMed

    Christelle, Tsague Dongmo; Hussainb, Hidayat; Dongo, Etienne; Julius, Oben Enyong; Hussain, Javid

    2011-08-01

    Cordia platythyrsa Baker is known for its medicinal value. This paper deals with a phytochemical investigation of this species, from which cordioxime (1), a new dioxime y-lactam has been isolated. Its structure was determined by comprehensive analyses of its 1H and 13C NMR, COSY, HMQC, and HMBC spectroscopic, and HREIMS data. The remaining two known compounds were identified as beta-sitosterol, and beta-sitosterol glucopyranoside.

  19. REGIOSELECTIVE GLYCOSYLATION: SYNTHESIS OF α-INDOLINE NUCLEOSIDES

    PubMed Central

    Brown, Kenneth L.; Chandra, Tilak; Zou, Shawn; Valente, Edward J.

    2005-01-01

    Novel indoline ribonucleosides with the α-N-glycoside configuration are synthesized with very high regioselectivity in 90–96% yield, using TMS protected indolines and 2,3-O-(1-methylethylidene)-5-O-(triphenylmethyl)-α/β-d-ribofuranose. The structures of these ribonucleosides were elucidated with X-ray crystallography as well as 2D (NOESY, COSY, and HMQC) NMR spectroscopy. PMID:16270659

  20. NMR study on (1alpha, 2beta, 4beta, 5alpha, 7beta)-7-[(hydroxydi-2-thienylacetyl) oxy]-9,9-dimethyl-3-oxa-9-azoniatricyclo [3.3.1.0(2,4)] nonane bromide monohydrate.

    PubMed

    Lin, Zhenguang; Mu, Yingdi; Liu, Yihui; Ren, Yeming; Lin, Jimao

    2010-03-01

    The structure of (1alpha, 2beta, 4beta, 5alpha, 7beta)-7-[(hydroxydi-2-thienylacetyl) oxy]-9,9-dimethyl-3-oxa-9-azoniatricyclo [3.3.1.0(2,4)] nonane bromide monohydrate was studied using 1D and 2D NMR techniques. Complete NMR assignments of the compound were obtained using DEPT, H-H COSY, as well as HMQC and HMBC heteronuclear correlation techniques. Copyright 2010 Elsevier B.V. All rights reserved.

  1. A New Sucrase Enzyme Inhibitor from Azadirachta indica.

    PubMed

    Abdelhady, Mohamed I S; Shaheen, Usama; Bader, Ammar; Youns, Mahmoud A

    2016-05-01

    Sucrase enzyme inhibitor considered as an oral anti-diabetic therapy that delays the absorption of eaten carbohydrates, reducing the postprandial glucose and insulin peaks to reach normoglycemia. Chromatographic fractionation of the hydroalcoholic extract of leaves of Azadirachta indica growing in KSA, followed by in-vitro assay of sucrase enzyme inhibition activity. This investigation led to the isolation of a new remarkable sucrase enzyme inhibitor; 4'-methyl Quercetin-7-O-β-D-glucuronopyranoside (1) alongside with four known compounds; 2,3-hexahydroxydiphenoyl-(α/β)-D-(4)C1-glucopyranose (2), Avicularin (3), Castalagin (4) and Quercetin-3-O-glucoside (5). The structure of the new compound (1) was elucidated on the basis of its spectral data, including ESI-MS, UV, (1)H NMR, (13)C NMR, (1)H-(1)H COSY, HSQC, NOESY and HMBC. Under the assay conditions, hydroalcoholic extract of A. indica and compounds 1-5 exhibited significant sucrase enzyme inhibitory activity. Chromatographic fractionation of the hydroalcoholic extract of leaves of Azadirachta indica, led to the Isolation of a new flavonoid glycoside named 4'-methyl Quercetin-7-O-β-D-glucuronopyranoside, alongside to other 4 known polyphenols. The hydroalcoholic extract as well as the isolated compounds exhibited significant sucrase enzyme inhibitory activity. Abbreviations used: ESI-MS; electrospray ionization-mass spectrometry, UV; ultraviolet, NMR; nuclear magnetic resonance, 1H-1H COSY; 1H-1H correlation spectroscopy, NOESY; nuclear overhauser effect spectroscopy, and HSQC; heteronuclear multiple bond correlation. A. indica; Azadirachta indica.

  2. Owariensisone: a new iridolactone from the whole plant of Brillantaisia owariensis P. Beauv.

    PubMed

    Foning Tebou, Perrin Lanversin; Mabou, Florence Déclaire; Ngnokam, David; Harakat, Dominique; Voutquenne-Nazabadioko, Laurence

    2016-07-01

    From the whole plant of Brillantaisia owariensis P. Beauv, a new iridolactone, owariensisone (1) together with six known compounds (nepetin-7-O-glucoside, choline, sucrose, mannitol, xylitol, 1-O-palmitoyl-2-eicosanoyl-3-O-(6-amino-6-deoxy)-β-d-glucopyranosyl-glycerol) were isolated. Structures of these compounds were established by direct interpretation of their spectral data, mainly HR-TOFESIMS, 1-D NMR ((1)H and (13)C) and 2-D NMR ((1)H-(1)H COSY, HSQC, HMBC, NOESY, TOCSY and DOCSY) and by comparison with the literature.

  3. Two new chalcone glycosides from the stems of Entada phaseoloides.

    PubMed

    Zhao, Zhong-xiang; Jin, Jing; Lin, Chao-zhan; Zhu, Chen-chen; Liu, Yi-ming; Lin, Ai-hua; Liu, Ying-xiang; Zhang, Li; Luo, Hua-feng

    2011-10-01

    Two new chalcone glycosides 4'-O-(6″-O-galloyl-β-d-glucopyranosyl)-2',4-dihydroxychalcone (1) and 4'-O-(6″-O-galloyl-β-d-glucopyranosyl)-2'-hydroxy-4-methoxychalcone (2) together with one known chalcone glycoside 4'-O-β-d-glucopyranosyl-2'-hydroxy-4-methoxychalcone (3) were isolated from the stems of Entada phaseoloides. The structures of the new compounds were elucidated on the basis of extensive spectroscopic analysis, including HSQC, HMBC, (1)H-(1)H COSY, and chemical evidences. This is the first report of chalcone-type compounds isolated from the genus Entada. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Cytotoxic benzil and coumestan derivatives from Tephrosia calophylla.

    PubMed

    Ganapaty, Seru; Srilakshmi, Guttula Veera Kantha; Pannakal, Steve Thomas; Rahman, Hafizur; Laatsch, Hartmut; Brun, Reto

    2009-01-01

    A benzil, calophione A, 1-(6'-Hydroxy-1',3'-benzodioxol-5'-yl)-2-(6''-hydroxy-2''-isopropenyl-2'',3''-dihydro-benzofuran-5''-yl)-ethane-1,2-dione and three coumestan derivatives, tephcalostan B, C and D were isolated from the roots of Tephrosia calophylla. Their structures were deduced from spectroscopic data, including 2D NMR (1)H-(1)H COSY and (13)C-(1)H COSY experiments. Compounds were evaluated for cytotoxicity against RAW (mouse macrophage cells) and HT-29 (colon cancer cells) cancer cell lines and antiprotozoal activity against various parasitic protozoa. Calophione A exhibited significant cytotoxicity with IC(50) of 5.00 (RAW) and 2.90microM (HT-29), respectively.

  5. Vibrational spectroscopic study, structural analysis, photophysical properties and theoretical calculations of cis-(±)-2,4,5-tris(pyridin-2-yl)imidazoline

    NASA Astrophysics Data System (ADS)

    Baldenebro-López, Jesús; Báez-Castro, Alberto; Glossman-Mitnik, Daniel; Höpfl, Herbert; Cruz-Enríquez, Adriana; Miranda-Soto, Valentín; Parra-Hake, Miguel; Campos-Gaxiola, José J.

    2017-02-01

    cis-(±)-2,4,5-tris(pyridin-2-yl)imidazoline has been fully characterized by FT-IR, FT-Raman, UV-Vis and fluorescence spectroscopy, one- and two-dimensional NMR spectroscopy (1H, 1H-1H gCOSY, 1H-1H gNOESY,13C{1H} ATP, 1H-13C and 1H-15N gHSQC and 1H-13C gHMBC), high-resolution mass spectrometry (HR-FAB+), TG-DSC analysis and low-temperature single-crystal X-ray diffraction analysis. Additionally, the molecular geometry and the vibrational infrared and Raman frequencies were calculated by density functional theory using the M06/6-31G(d) level of theory, showing good agreement with the experimental results. The title compound showed interesting photophysical properties, which were studied experimentally in solution and in the solid state by UV-Vis and fluorescence spectroscopy and compared to the theoretically obtained parameters using TD-DFT calculations. Natural and Mulliken atomic charges and the molecular electrostatic potential (MEP) have been mapped.

  6. 5-Acetamido-3,5-dideoxy-L-glycero-L-manno-non-2-ulosonic acid-containing O-polysaccharide from marine bacterium Pseudomonas glareae KMM 9500T.

    PubMed

    Kokoulin, Maxim S; Kalinovsky, Anatoly I; Romanenko, Lyudmila A; Mikhailov, Valery V

    2018-05-22

    The O-polysaccharide was isolated from the lipopolysaccharide of a marine bacterium Pseudomonas glareae KMM 9500 T and studied by chemical methods along with 1D and 2D 1 H and 13 C NMR spectroscopy including 1 H, 1 H-TOCSY, 1 H, 1 H-COSY, 1 H, 1 H-ROESY, 1 H, 13 C-HSQC and 1 H, 13 C-HMBC experiments. The O-polysaccharide was found to consist of linear tetrasaccharide repeating units constituted by D-glucuronic acid (D-GlcA), L-rhamnose (L-Rha), D-glucose (D-Glc) and 5-acetamido-7,9-O-[(S)-1-carboxyethylidene]-3,5-dideoxy-L-glycero-L-manno-non-2-ulosonic acid (Sug7,9(S-Pyr)), partially O-acetylated at position 8 (∼70%): →4)-α-D-GlcpA-(1→3)-β-L-Rhap-(1→4)-β-D-Glcp-(1→4)-β-Sugp8Ac(∼70%)7,9(S-Pyr)-(2→. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Combining multinuclear high-resolution solid-state MAS NMR and computational methods for resonance assignment of glutathione tripeptide.

    PubMed

    Sardo, Mariana; Siegel, Renée; Santos, Sérgio M; Rocha, João; Gomes, José R B; Mafra, Luis

    2012-06-28

    We present a complete set of experimental approaches for the NMR assignment of powdered tripeptide glutathione at natural isotopic abundance, based on J-coupling and dipolar NMR techniques combined with (1)H CRAMPS decoupling. To fully assign the spectra, two-dimensional (2D) high-resolution methods, such as (1)H-(13)C INEPT-HSQC/PRESTO heteronuclear correlations (HETCOR), (1)H-(1)H double-quantum (DQ), and (1)H-(14)N D-HMQC correlation experiments, have been used. To support the interpretation of the experimental data, periodic density functional theory calculations together with the GIPAW approach have been used to calculate the (1)H and (13)C chemical shifts. It is found that the shifts calculated with two popular plane wave codes (CASTEP and Quantum ESPRESSO) are in excellent agreement with the experimental results.

  8. Oxidative degradation of silica-supported polyethylenimine for CO2 adsorption: insights into the nature of deactivated species.

    PubMed

    Ahmadalinezhad, Asieh; Sayari, Abdelhamid

    2014-01-28

    The oxidative degradation of polyethylenimine-impregnated mesoporous SBA-15 silica for CO2 capture was investigated at the molecular level. The adsorbents were exposed to flowing air at different temperatures, and their degree of deactivation was evaluated through the measurement of CO2 adsorption capacity prior and subsequent to air exposure. A solvent-extraction method was employed to isolate the deactivated species from the silica support. The extracted species were investigated by a variety of 1D and 2D NMR techniques such as (13)C, (1)H, (1)H-(15)N HMBC, (1)H-(13)C HMQC, and (1)H-(13)C HMBC. This in-depth investigation showed that they contain predominantly fragments involving imine and carbonyl groups. Several structural units were conclusively established.

  9. Total NMR assignments of new [C7-O-C7'']-biflavones from leaves of the limonene-carvone chemotype of Lippia alba (Mill) N. E. Brown.

    PubMed

    Barbosa, Francisco Geraldo; Lima, Mary Anne Sousa; Silveira, Edilberto Rocha

    2005-04-01

    Phytochemical analysis of leaves of the limonene-carvone chemotype of Lippia alba led to the isolation of two biflavonoids with a new structural pattern with an ether linkage: 5,5''-dihydroxy-6,4',6'',3''',4'''-pentamethoxy-[C(7)--O--C(7'')]-biflavone (1) and 4',4,5,5''-tetrahydroxy-6,6'',3'''-trimethoxy-[C(7)--O--C(7'')]-biflavone (2). Structural elucidation of the new compounds was established on the basis of spectral data, through the use of 1D NMR and several 2D shift correlated NMR pulse sequences (COSY, HMQC, HMBC and NOESY). Copyright (c) 2005 John Wiley & Sons, Ltd

  10. Chemical analysis of a polysaccharide of unripe (green) tomato (Lycopersicon esculentum).

    PubMed

    Chandra, Krishnendu; Ghosh, Kaushik; Ojha, Arnab K; Islam, Syed S

    2009-11-02

    A polysaccharide (PS-I) isolated from the aqueous extract of the unripe (green) tomatoes (Lycopersicon esculentum) consists of D-galactose, D-methyl galacturonate, D-arabinose, L-arabinose, and L-rhamnose. Structural investigation of the polysaccharide was carried out using total acid hydrolysis, methylation analysis, periodate oxidation study, and NMR studies ((1)H, (13)C, DQF-COSY, TOCSY, NOESY, ROESY, HMQC, and HMBC). On the basis of above-mentioned experiments the structure of the repeating unit of the polysaccharide (PS-I) was established as: [structure: see text].

  11. Forazoline A: Marine-derived polyketide with antifungal in vivo efficacy

    DOE PAGES

    Wyche, Thomas P.; Piotrowski, Jeff S.; Hou, Yanpeng; ...

    2014-09-04

    Forazoline A, a novel antifungal polyketide with in vivo efficacy against Candida albicans, was discovered using LCMS-based metabolomics to investigate marine-invertebrate-associated bacteria. Forazoline A had a highly unusual and unprecedented skeleton. Acquisition of 13C– 13C gCOSY and 13C– 15N HMQC NMR data provided the direct carbon–carbon and carbon–nitrogen connectivity, respectively. This approach represents the first example of determining direct 13C– 15N connectivity for a natural product. In this paper, using yeast chemical genomics, we propose that forazoline A operated through a new mechanism of action with a phenotypic outcome of disrupting membrane integrity.

  12. A new furostanol glycoside from Tribulus terrestris.

    PubMed

    Xu, Yajuan; Liu, Yonghong; Xu, Tunhai; Xie, Shengxu; Si, Yunshan; Liu, Yue; Zhou, Haiou; Liu, Tonghua; Xu, Dongming

    2010-01-27

    Besides two known glycosides, a new furostanol glycoside was isolated from the Fruits of Tribulus terrestris L. The structure of the new furostanol glycoside was established as 26-O-beta-D-glucopyranosyl-(25S)-5alpha-furostane-20(22)-en-12-one-3beta, 26-diol-3-O-alpha-L-rhamnopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->4)]-beta-D-galactopyranoside (1) on the basis of 1D and 2D-NMR techniques, including COSY, HMBC, and HMQC correlations.

  13. A new triterpenoid saponin from Gymnema sylvestre.

    PubMed

    Zhang, Man-Qi; Liu, Yue; Xie, Sheng-Xu; Xu, Tun-Hai; Liu, Tong-Hua; Xu, Ya-Juan; Xu, Dong-Ming

    2012-01-01

    Besides four known compounds, a new triterpenoid saponin was isolated from the stems of Gymnema sylvestre. The structure of the new triterpenoid saponin was established as 3β,16β,22α-trihydroxy-olean-12-ene 3-O-β-D-xylopyranosyl-(1 → 6)-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranoside (1) on the basis of 1D and 2D NMR techniques, including COSY, HMBC, HMQC, and NOESY correlations. Four known compounds 2, 3, 4, and 5 were identified on the basis of spectroscopic data.

  14. Cucurbitane-type triterpenoids from the fruit pulp of Momordica charantia.

    PubMed

    Liao, Yun-Wen; Chen, Chiy-Rong; Kuo, Yueh-Hsiung; Hsu, Jue-Liang; Shih, Wen-Ling; Cheng, Hsueh-Ling; Huang, Tzou-Chi; Chang, Chi-I

    2012-12-01

    Three new cucurbitane-type triterpenoids, 5beta,19-epoxy-23(R)-methoxycucurbita-6,24-dien-3beta-ol (1), 5beta,19-epoxy-23(S)-methoxycucurbita-6,24-dien-3beta-ol (2), and 3beta-hydroxy-23(R)-methoxycucurbita-6,24-dien-5beta,19-olide (3), were isolated from the fruit pulp of Momordica charantia. Their structures were established on the basis of extensive NMR (1H, 13C, COSY, HMQC, HMBC, and NOESY) and EI-MS studies. Compound 1 exhibited cytotoxic activity against the SK-Hep 1 cell line.

  15. Two new 24-isopropenyl-lanostanoids from Tillandsia brachycaulos.

    PubMed

    Cantillo-Ciau, Zulema; Mena-Rejón, Gonzalo J; Quintero-Mármol, Esther; Jiménez-Díaz, Antonio; Quijano, Leovigildo

    2003-01-01

    The leaves of Tillandsia brachycaulos afforded two novel tetracyclic triterpenoids identified as (24S)-24-isopropenyl-29-nor-5alpha-lanosta-7-en-3beta-ol (1) and (24S)-24-isopropenyl-29-nor-5alpha-lanosta-7-en-3-one (2), in addition to the known isopimaric acid (3) and chlorogenic acid (4). Their structures were elucidated on the basis of spectral analysis, including homo- and heteronuclear correlation NMR experiments (COSY, ROESY, HMQC and HMBC) and by comparison with data in the literature. The antimicrobial and antifungal activities were studied. The compounds did not show significant activity.

  16. A new isocoumarin from Cajanus cajan (Fabaceae).

    PubMed

    Rodrigues, Virginia F; Oliveira, Rodrigo R; Vega, Maria Raquel G

    2014-04-01

    A new isocoumarin, 3-phenyl-8-hydroxy-6-methoxy-5-gamma,gamma-dimethylallyl-isocoumarin, named cajavilmina (1) and eight known compounds: a-amirenone (2), beta-amirenone (3), lupenone (4), 5-hydroxy-7-methoxydihydroflavone (5), longistilin C (6), 3-hydroxy-5-methoxystilbene (7), beta-sitosterol (8) and stigmasterol (9) were identified in a dichloromethane fraction from Cajanus cajan leaves. Structures were elucidated by analysis of spectral data, mainly those afforded by 1H, NOEDIFF and 13C NMR (1D and 2D NMR HMQC, HMBC and COSY) and mass spectra.

  17. New phenethyl alcohol glycosides from Stachys parviflora.

    PubMed

    Ahmad, Viqar Uddin; Arshad, Saima; Bader, Sadia; Ahmed, Amir; Iqbal, Shazia; Tareen, Rasool Buksh

    2006-01-01

    Phytochemical investigations of the whole plant of Stachys parviflora (Lamiaceae) resulted in the isolation of two new phenethyl alcohol glycosides. The structures of the new compounds named parviflorosides A and B were established as 2-(3,4-dihydroxyphenyl)-ethyl-O-alpha-L-rhamnopyranosyl-(1 --> 2)-4-O-E-caffeoyl-beta-D-glucopyranoside (1) and 2-(3,4-dihydroxyphenyl)-ethyl-O-alpha-L-rhamnopyranosyl-(1 --> 2)-6-O-E-caffeoyl-beta-D-glucopyranoside (2), respectively. The structure elucidation of the new compounds was based primarily on 1D and 2D NMR analysis, including COSY, HMBC and HMQC correlations.

  18. A New Sucrase Enzyme Inhibitor from Azadirachta indica

    PubMed Central

    Abdelhady, Mohamed I. S.; Shaheen, Usama; Bader, Ammar; Youns, Mahmoud A.

    2016-01-01

    Background: Sucrase enzyme inhibitor considered as an oral anti-diabetic therapy that delays the absorption of eaten carbohydrates, reducing the postprandial glucose and insulin peaks to reach normoglycemia. Materials and Methods: Chromatographic fractionation of the hydroalcoholic extract of leaves of Azadirachta indica growing in KSA, followed by in-vitro assay of sucrase enzyme inhibition activity. Results: This investigation led to the isolation of a new remarkable sucrase enzyme inhibitor; 4’-methyl Quercetin-7-O-β-D-glucuronopyranoside (1) alongside with four known compounds; 2,3-hexahydroxydiphenoyl-(α/β)-D-4C1-glucopyranose (2), Avicularin (3), Castalagin (4) and Quercetin-3-O-glucoside (5). The structure of the new compound (1) was elucidated on the basis of its spectral data, including ESI-MS, UV, 1H NMR, 13C NMR, 1H-1H COSY, HSQC, NOESY and HMBC. Conclusion: Under the assay conditions, hydroalcoholic extract of A. indica and compounds 1-5 exhibited significant sucrase enzyme inhibitory activity. SUMMARY Chromatographic fractionation of the hydroalcoholic extract of leaves of Azadirachta indica, led to the Isolation of a new flavonoid glycoside named 4’-methyl Quercetin-7-O-β-D-glucuronopyranoside, alongside to other 4 known polyphenols. The hydroalcoholic extract as well as the isolated compounds exhibited significant sucrase enzyme inhibitory activity. Abbreviations used: ESI-MS; electrospray ionization-mass spectrometry, UV; ultraviolet, NMR; nuclear magnetic resonance, 1H-1H COSY; 1H-1H correlation spectroscopy, NOESY; nuclear overhauser effect spectroscopy, and HSQC; heteronuclear multiple bond correlation. A. indica; Azadirachta indica. PMID:27563214

  19. Isolation and anti-hepatitis B virus activity of dibenzocyclooctadiene lignans from the fruits of Schisandra chinensis.

    PubMed

    Xue, Yongbo; Li, Xifeng; Du, Xue; Li, Xiaonian; Wang, Weiguang; Yang, Jianhong; Chen, Jijun; Pu, Jianxin; Sun, Handong

    2015-08-01

    Seven lignans with a dibenzocyclooctadiene skeleton, termed schinlignans A-G, and a 6,7-seco-homolignan, schischinone, together with seven known lignans, were isolated from the fruits of Schisandra chinensis (Turcz.) Baill. Their structures were elucidated by extensive spectroscopic methods, including HRESIMS, IR, UV, and 2D NMR (COSY, HMQC, COSY, and HMBC experiments). The stereochemistry at the chiral centers and the biphenyl moiety, were determined using ROESY, as well as via interpretation of their ECD spectra. Schinlignan G and methylgomisin O exhibited potent anti-hepatitis B virus activity against HBV DNA replication with IC50 values of 5.13 and 5.49μgmL(-1), respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Epitaxial CoSi2 on MOS devices

    DOEpatents

    Lim, Chong Wee; Shin, Chan Soo; Petrov, Ivan Georgiev; Greene, Joseph E.

    2005-01-25

    An Si.sub.x N.sub.y or SiO.sub.x N.sub.y liner is formed on a MOS device. Cobalt is then deposited and reacts to form an epitaxial CoSi.sub.2 layer underneath the liner. The CoSi.sub.2 layer may be formed through a solid phase epitaxy or reactive deposition epitaxy salicide process. In addition to high quality epitaxial CoSi.sub.2 layers, the liner formed during the invention can protect device portions during etching processes used to form device contacts. The liner can act as an etch stop layer to prevent excessive removal of the shallow trench isolation, and protect against excessive loss of the CoSi.sub.2 layer.

  1. Identification of rare 6-deoxy-D-altrose from an edible mushroom (Lactarius lividatus).

    PubMed

    Tako, Masakuni; Dobashi, Yahiko; Tamaki, Yukihiro; Konishi, Teruko; Yamada, Masashi; Ishida, Hideharu; Kiso, Makoto

    2012-03-01

    6-Deoxy-L-altrose is well known as a constituent sugar moiety of lipopolysaccharides in Gram-negative bacteria. However, its isomer, 6-deoxy-D-altrose, is little known. Identification of 6-deoxy-D-altrose isolated from a polysaccharide extracted from an edible mushroom (Lactarius lividatus), its comparison with chemically synthesized 6-deoxy-D-altrose using (1)H and (13)C NMR including COSY, HMQC spectroscopy, and investigation of its specific optical rotation were all conducted in this study. The 6-deoxy-hexose isolated from acid hydrolysate of the polysaccharide extracted from L. lividatus was involved in four anomeric isomers (α-pyranose and β-pyranose, and α-furanose and β-furanose), as was chemically synthesized 6-deoxy-d-altrose in an aqueous solution because of mutarotation. Almost all signals of 1D ((1)H NMR and (13)C NMR) and 2D (COSY and HMQC)-NMR spectra agreed with those of the authentic 6-deoxy-D-altrose. The specific optical rotation [α](589) of 6-deoxy-sugar showed a value of +18.2°, which was in agreement with that of authentic 6-deoxy-D-altrose. Consequently, 6-deoxy-hexose was identified as the 6-deoxy-D-altrose. This work is the first complete identification of 6-deoxy-D-altrose in a natural environment. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. A new ent-clerodane diterpenoid from Crassocephalum bauchiense Huch. (Asteraceae).

    PubMed

    Tchinda, Alembert T; Mouokeu, Simplice R; Ngono, Rosalie A N; Ebelle, Madeleine R E; Mokale, Aristide L K; Nono, Diane K; Frédérich, Michel

    2015-01-01

    A phytochemical investigation of the whole plant of Crassocephalum bauchiense Huch. resulted in the isolation of a new clerodane diterpenoid, ent-2β,18,19-trihydroxycleroda-3,13-dien-16,15-olide (1), together with two known flavonoids 3',5-dihydroxy-4',5',6,7,8-pentamethoxyflavone (2) and 4',5-dihydroxy-3',5',6,7,8-pentamethoxyflavone (3). The compounds were tested against the chloroquine-sensitive 3D7 strain of Plasmodium falciparum. Compound 2 showed weak activity (IC50 = 10.1 g/mL) whilst compounds 1 and 3 were inactive. The structures of the compounds were elucidated by using detailed spectral analyses, especially (1)H and (13)C NMR, (1)H-(1)H COSY, NOESY, HMBC and HR-ESI-MS.

  3. Antimycobacterial physalins from Physalis angulata L. (Solanaceae).

    PubMed

    Januário, A H; Filho, E Rodrigues; Pietro, R C L R; Kashima, S; Sato, D N; França, S C

    2002-08-01

    Crude extracts and fractions from aerial parts of Physalis angulata have been bioassayed for antimycobacterial activity. Fraction A1-29-12 containing physalins B, F and D exhibited a minimum inhibitory concentration value (MIC) against Mycobacterium tuberculosis H(37)Rv strain of 32 microg/mL. Purified physalin B and physalin D were also tested showing MIC values against Mycobacterium tuberculosis H(37)Rv strain of > 128 microg/mL and 32 microg/mL respectively, suggesting that physalin D plays a relevant role in the antimycobacterial activity displayed. Structural elucidation of both physalins D and B was based on detailed (13)C and (1)H NMR spectral analysis with the aid of 2D-correlation spectroscopy ((1)H-(1)H, COSY, HSQC and HMBC). The assignment of the (13)C chemical shift for physalin D is reported here for the first time. Copyright 2002 John Wiley & Sons, Ltd.

  4. Identification of new diterpene esters from green Arabica coffee beans, and their platelet aggregation accelerating activities.

    PubMed

    Wang, Xia; Meng, QianQian; Peng, XingRong; Hu, GuiLin; Qiu, MingHua

    2018-10-15

    Eight new ent-kaurane diterpene fatty acid esters, namely caffarolides A-H (1-8), were isolated from green beans of Coffea arabica. Their chemical structures were confirmed by extensive spectroscopic analysis including 1D, 2D NMR (HSQC, HMBC, 1 H- 1 H COSY, and ROESY), HRMS, IR and CD spectra and by GC-FID analysis. Interestingly, the diterpene moiety of these new compounds first occurred in genus Coffea. All the isolates were evaluated for platelet aggregation activity in vitro. As the results, caffarolides C, D and F (3, 4 and 6) showed induction effect for platelet aggregation and the possible structure-activity relationships have been discussed briefly. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Trifasciatosides A-J, Steroidal Saponins from Sansevieria trifasciata.

    PubMed

    Teponno, Rémy Bertrand; Tanaka, Chiaki; Jie, Bai; Tapondjou, Léon Azefack; Miyamoto, Tomofumi

    2016-01-01

    Four previously unreported steroidal saponins, trifasciatosides A-D (1-4), three pairs of previously undescribed steroidal saponins, trifasciatosides E-J (5a, b-7a, b) including acetylated ones, together with twelve known compounds were isolated from the n-butanol soluble fraction of the methanol extract of Sansevieria trifasciata. Their structures were elucidated on the basis of detailed spectroscopic analysis, including (1)H-NMR, (13)C-NMR, (1)H-(1)H correlated spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond connectivity (HMBC), total correlated spectroscopy (TOCSY), nuclear Overhauser enhancement and exchange spectroscopy (NOESY), electrospray ionization-time of flight (ESI-TOF)-MS and chemical methods. Compounds 2, 4, and 7a, b exhibited moderate antiproliferative activity against HeLa cells.

  6. New furostanol saponins with anti-inflammatory and cytotoxic activities from the rhizomes of Smilax davidiana.

    PubMed

    Zhou, Meng; Huang, Liping; Li, Linyu; Wei, Yifei; Shu, Jicheng; Liu, Xing; Huang, Huilian

    2017-11-01

    Seven new furostanol saponins have been isolated from the rhizomes of Smilax davidiana. Their structures were established by 2D NMR spectroscopic techniques ( 1 H, 1 H-COSY, NOESY, HSQC and HMBC), mass spectrometry and comparison with the literature. The isolated compounds were subjected to evaluate anti-inflammatory and cytotoxic activities in vitro. Compounds 3, 5 and 7 were found to have modest anti-inflammatory effects through suppression of IL-1β production and promote the expression of IL-10 in LPS-stimulated RAW 264.7 cells. Davidianoside F (6) showed activity against MCF-7 and HELA cell lines at the concentration of 10.2µM and 4.3µM, respectively. Copyright © 2017. Published by Elsevier Inc.

  7. Antiproliferative Cardenolide Glycosides of Elaeodendron alluaudianum from the Madagascar Rainforest1

    PubMed Central

    Hou, Yanpeng; Cao, Shugeng; Brodie, Peggy; Callmander, Martin; Ratovoson, Fidisoa; Randrianaivo, Richard; Rakotobe, Etienne; Rasamison, Vincent E.; Rakotonandrasana, Stephan; TenDyke, Karen; Suh, Edward M.; Kingston, David G. I.

    2010-01-01

    Bioassay-guided fractionation of an ethanol extract of a Madagascar collection of Elaeodendron alluaudianum led to the isolation of two new cardenolide glycosides (1 and 2). The 1H and 13C NMR spectra of both compounds were fully assigned using a combination of 2D NMR experiments, including 1H-1H COSY, HSQC, HMBC, and ROESY sequences. Both compounds 1 and 2 were tested against the A2780 human ovarian cancer cell line and the U937 human histiocytic lymphoma cell line assays, and showed significant antiproliferative activity with IC50 values of 0.12 and 0.07 μM against the A2780 human ovarian cancer cell line, and 0.15 and 0.08 μM against the U937 human histiocytic lymphoma cell line, respectively. PMID:19058971

  8. Three new fatty acids from the roots of Boehmeria nivea (L.) Gaudich and their antifungal activities.

    PubMed

    Xu, Qiong-Ming; Liu, Yan-Li; Li, Xiao-Ran; Li, Xia; Yang, Shi-Lin

    2011-03-01

    Three new unsaturated fatty acids, (Z)-9,10,11-trihydroxy-12-octadecenoic acid (1), (Z)-7,8,9-trihydroxy-10-hexadecenoic acid (2) and (Z)-12-keto-7,8,9-trihydroxy-10-hexadecenoic acid (3) were isolated from the roots of Boehmeria nivea (L.) Gaudich, along with a known unsaturated fatty acid, (E)-8,11,12-trihydroxy-9-octadecenoic acid (4). The structures of the new compounds were established by HR ESI-MS, (1)H, (13)C, 2D ((1)H-(1)H COSY, HSQC, HMBC) NMR experiments. The known compound was identified by a comparison of its spectral data with published references. The three new compounds showed some antifungal activities by agar assay.

  9. Structural and immunochemical studies of neutral exopolysaccharide produced by Lactobacillus johnsonii 142.

    PubMed

    Górska, Sabina; Jachymek, Wojciech; Rybka, Jacek; Strus, Magdalena; Heczko, Piotr B; Gamian, Andrzej

    2010-01-11

    This paper describes the structure of neutral exopolysaccharide (EPS) produced by Lactobacillus johnsonii 142, strain of the lactic acid bacteria isolated from the intestine of mice with experimentally induced inflammatory bowel disease (IBD). Sugar and methylation analyses along with (1)H and (13)C NMR spectroscopy, including two-dimensional (1)H,(1)H COSY, TOCSY, NOESY, and (1)H,(13)C HSQC experiments revealed that the repeating unit of the EPS is a pentasaccharide: -->3)-alpha-D-Galp-(1-->3)-beta-d-Glcp-(1-->5)-beta-D-Galf-(1-->3)-alpha-D-Galp-(1-->3)-alpha-D-Galp-(1--> The rabbit antiserum raised against whole cells of L. johnsonii 142 reacted with homologous EPS, and cross-reacted with exopolysaccharide from Lactobacillus animalis/murinus 148 isolated also from mice with IBD, but not reacted with EPS of L. johnsonii 151 from healthy mice. Copyright 2009 Elsevier Ltd. All rights reserved.

  10. Photochemical route to actinide-transition metal bonds: synthesis, characterization and reactivity of a series of thorium and uranium heterobimetallic complexes.

    PubMed

    Ward, Ashleigh L; Lukens, Wayne W; Lu, Connie C; Arnold, John

    2014-03-05

    A series of actinide-transition metal heterobimetallics has been prepared, featuring thorium, uranium, and cobalt. Complexes incorporating the binucleating ligand N[ο-(NHCH2P(i)Pr2)C6H4]3 with either Th(IV) (4) or U(IV) (5) and a carbonyl bridged [Co(CO)4](-) unit were synthesized from the corresponding actinide chlorides (Th: 2; U: 3) and Na[Co(CO)4]. Irradiation of the resulting isocarbonyls with ultraviolet light resulted in the formation of new species containing actinide-metal bonds in good yields (Th: 6; U: 7); this photolysis method provides a new approach to a relatively unusual class of complexes. Characterization by single-crystal X-ray diffraction revealed that elimination of the bridging carbonyl and formation of the metal-metal bond is accompanied by coordination of a phosphine arm from the N4P3 ligand to the cobalt center. Additionally, actinide-cobalt bonds of 3.0771(5) Å and 3.0319(7) Å for the thorium and uranium complexes, respectively, were observed. The solution-state behavior of the thorium complexes was evaluated using (1)H, (1)H-(1)H COSY, (31)P, and variable-temperature NMR spectroscopy. IR, UV-vis/NIR, and variable-temperature magnetic susceptibility measurements are also reported.

  11. Photochemical route to actinide-transition metal bonds: synthesis, characterization and reactivity of a series of thorium and uranium heterobimetallic complexes

    SciTech Connect

    Ward, Ashleigh; Lukens, Wayne; Lu, Connie

    2014-04-01

    A series of actinide-transition metal heterobimetallics has been prepared, featuring thorium, uranium and cobalt. Complexes incorporating the binucleating ligand N[-(NHCH2PiPr2)C6H4]3 and Th(IV) (4) or U(IV) (5) with a carbonyl bridged [Co(CO)4]- unit were synthesized from the corresponding actinide chlorides (Th: 2; U: 3) and Na[Co(CO)4]. Irradiation of the isocarbonyls with ultraviolet light resulted in the formation of new species containing actinide-metal bonds in good yields (Th: 6; U: 7); this photolysis method provides a new approach to a relatively rare class of complexes. Characterization by single-crystal X-ray diffraction revealed that elimination of the bridging carbonyl is accompanied by coordination ofmore » a phosphine arm from the N4P3 ligand to the cobalt center. Additionally, actinide-cobalt bonds of 3.0771(5) and 3.0319(7) for the thorium and uranium complexes, respectively, were observed. The solution state behavior of the thorium complexes was evaluated using 1H, 1H-1H COSY, 31P and variable-temperature NMR spectroscopy. IR, UV-Vis/NIR, and variable-temperature magnetic susceptibility measurements are also reported.« less

  12. Developing SABRE as an analytical tool in NMR

    NASA Astrophysics Data System (ADS)

    Lloyd, Lyrelle Stacey

    Work presented in this thesis centres around the application of the new hyperpolarisation technique, SABRE, within nuclear magnetic resonance spectroscopy, focusing on optimisation of the technique to characterise small organic molecules. While pyridine was employed as a model substrate, studies on a range of molecules are investigated including substituted pyridines, quinolines, thiazoles and indoles are detailed. Initial investigations explored how the properties of the SABRE catalyst effect the extent of polarisation transfer exhibited. The most important of these properties proved to be the rate constants for loss of pyridine and hydrides as these define the contact time of pyridine with the parahydrogen derived hydride ligands in the metal template. The effect of changing the temperature, solvent or concentration of substrate or catalyst are rationalised. For instance, the catalyst ICy(a) exhibits relatively slow ligand exchange rates and increasing the temperature during hyperpolarisation increases the observed signal enhancements. These studies have revealed a second polarisation transfer template can be used with SABRE in which two substrate molecules are bound. This allows the possibility of investigation of larger substrates which might otherwise be too sterically encumbered to bind. Another significant advance relates to the first demonstration that SABRE can be used in conjunction with an automated system designed with Bruker allowing the acquisition of scan averaged, phase cycled and traditional 2D spectra. The system also allowed investigations into the effect of the polarisation transfer field and application of that knowledge to collect single-scan 13C data for characterisation. The successful acquisition of 1H NOESY, 1H-1H COSY, 1H-13C 2D and ultrafast 1H-1H COSY NMR sequences is detailed for a 10 mM concentration sample, with 1H data collected for a 1 mM sample. A range of studies which aim to demonstrate the applicability of SABRE to the

  13. A discrete three-layer stack aggregate of a linear porphyrin tetramer: solution-phase structure elucidation by NMR and X-ray scattering.

    PubMed

    Hutin, Marie; Sprafke, Johannes K; Odell, Barbara; Anderson, Harry L; Claridge, Tim D W

    2013-08-28

    Formation of stacked aggregates can dramatically alter the properties of aromatic π-systems, yet the solution-phase structure elucidation of these aggregates is often impossible because broad distributions of species are formed, giving uninformative spectroscopic data. Here, we show that a butadiyne-linked zinc porphyrin tetramer forms a remarkably well-defined aggregate, consisting of exactly three molecules, in a parallel stacked arrangement (in chloroform at room temperature; concentration 1 mM-0.1 μM). The aggregate has a mass of 14.7 kDa. Unlike most previously reported aggregates, it gives sharp NMR resonances and aggregation is in slow exchange on the NMR time scale. The structure was elucidated using a range of NMR techniques, including diffusion-editing, (1)H-(29)Si HMBC, (1)H-(1)H COSY, TOCSY and NOESY, and (1)H-(13)C edited HSQC spectroscopy. Surprisingly, the (1)H-(1)H COSY spectrum revealed many long-range residual dipolar couplings (RDCs), and detailed analysis of magnetic field-induced (1)H-(13)C RDCs provided further evidence for the structural model. The size and shape of the aggregate is supported by small-angle X-ray scattering (SAXS) data. It adopts a geometry that maximizes van der Waals contact between the porphyrins, while avoiding clashes between side chains. The need for interdigitation of the side chains prevents formation of stacks consisting of more than three layers. Although a detailed analysis has only been carried out for one compound (the tetramer), comparison with the NMR spectra of other oligomers indicates that they form similar three-layer stacks. In all cases, aggregation can be prevented by addition of pyridine, although at low pyridine concentrations, disaggregation takes many hours to reach equilibrium.

  14. Antidepressent Effect of Two New Benzyl Derivatives from Wild Strawberry Fragaria vesca var. nubicola Lindl. ex Hook.f.

    PubMed

    Naz, Sadia; Farooq, Umar; Khan, Ajmal; Khan, Haroon; Karim, Nasiara; Sarwar, Rizwana; Hussain, Javid; Rauf, Abdur

    2017-01-01

    Two new benzyl derivatives were isolated from ethyl acetate fraction of wild strawberry, Fragaria vesca var. nubicola Lindl. ex Hook.f. The structures of these compounds were elucidated to be 5-(4-hydroxy-3-methoxyphenethyl)-7-methoxy-2H-chromen-3-ol ( 1 ) and 5-(4-hydroxy-3-methoxyphenethyl)-4,7-dimethoxy-2H-chromen-3-ol ( 2 ) based on spectroscopic data through IR, UV, 1 H-NMR, 13 C-NMR along with two dimensional (2D) techniques HMBC, HMQC, and COSY. Both compounds 1 and 2 were studied in tail suspension and forced swim tests for antidepressant like effects. A significant dose dependent antidepressant like effect was observed by causing spontaneous anti-immobility at various test doses upon intraperitoneal administration.

  15. Structure of a novel α-glucan substitute with the rare 6-deoxy-D-altrose from Lactarius lividatus (mushroom).

    PubMed

    Tako, Masakuni; Dobashi, Yahiko; Shimabukuro, Junpei; Yogi, Takuya; Uechi, Keiko; Tamaki, Yukihiro; Konishi, Teruko

    2013-02-15

    A novel α-glucan substituted rare 6-deoxy-D-altropyranose was isolated from edible fruiting bodies of a mushroom (Lactarius lividatus) grown in Okinawa, Japan. The polysaccharide consists of D-glucose, D-galactose and 6-deoxy-D-altrose in a molar ratio of 3.0:1.0:1.0. The specific rotation [α](589) was estimated as +64.3° (0.2% in water) at 25 °C. Based on results of IR, NMR ((1)H, (13)C, 2D-COSY, 2D-HMQC, 2D-ROESY and 2D-HMBC), and methylation analyses, the structure of the polysaccharide was determined as [formula, see text] This work is the first demonstration of rare 6-deoxy-D-altropyranose moiety on polysaccharides. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Antibacterial colorants: characterization of prodiginines and their applications on textile materials.

    PubMed

    Alihosseini, Farzaneh; Ju, Kou-San; Lango, Jozsef; Hammock, Bruce D; Sun, Gang

    2008-01-01

    A strain of Vibrio sp. isolated from marine sediments produced large quantities of bright red pigments that could be used to dye many fibers including wool, nylon, acrylics, and silk. Characterization of the pigments by electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) revealed three prodiginine-like structures with nonpolar characteristics and low molecular mass. UV-visible spectra of the major constituent in methanol solution showed absorbance at lambda max 530 nm wavelength. The accurate mass result showed that the main isolated product has a molecular mass of m/z 323.1997. Further analysis using mass fragmentation (MS/MS), 1H NMR, COSY, HMQC NMR and DEPT confirmed the detailed structure of the pigment with an elementary composition of C20H25N3O. Fabrics dyed with the microbial prodiginines demonstrated antibacterial activity.

  17. A novel daucosterol derivative and antibacterial activity of compounds from Arctotis arctotoides.

    PubMed

    Sultana, Nasim; Afolayan, A J

    2007-08-01

    Arctotis arctotoides is a perennial herb used medicinally for the treatment of various ailments in the Eastern Cape, South Africa. Different extracts of the plant were investigated for their antimicrobial constituents. This led to the isolation and identification of a new daucosterol derivative 3-O-[beta-D-(6'-nonadeanoate)glucopyranosyl]-beta-sitosterol and seven known compounds namely: serratagenic acid, stigmasterol, daucosterol, zaluzanin D, dehydrocostuslactone, nepetin, and pedalitin. The structures of the compounds were elucidated on the basis of spectral analysis, including homo and hetero nuclear correlation NMR experiments (COSY, NOESY, HMQC, HMBC) and mass spectra as well as by comparison with available data in the literature. The compounds exhibited antibacterial activity except stigmasterol, daucosterol and dehydrocostuslactone. Nepetin was the most active against Bacillus subtilis and Staphylococcus aureus with the minimum inhibitory concentrations of 4 microg mL( - 1) and 31 microg mL( - 1), respectively, while others exhibited moderate activity.

  18. Diprenylated chalcones and other constituents from the twigs of Dorstenia barteri var. subtriangularis.

    PubMed

    Ngameni, Barthelemy; Ngadjui, Bonaventure T; Folefoc, Gabriel N; Watchueng, Jean; Abegaz, Berhanu M

    2004-02-01

    The twigs of Dorstenia barteri var. subtriangularis yielded three diprenylated chalcones: (-)-3-(3,3-dimethylallyl)-5'-(2-hydroxy-3-methylbut-3-enyl)-4,2',4'-trihydroxychalcone, (+)-3-(3,3-dimethylallyl)-4',5'-[2'''-(1-hydroxy-1-methylethyl)-dihydrofurano]-4,2'-dihydroxychalcone and 3,4-(6",6"-dimethyldihydropyrano)-4',5'-[2''',-(1-hydroxy-1-methylethyl)-dihydrofurano]-2'-hydroxychalcone for which the names bartericins A, B and C, respectively, are proposed. Stipulin, beta-sitosterol and its 3-beta-D-glucopyranosyl derivative were also isolated. The structures of these secondary metabolites were determined on the basis of spectroscopic analysis, especially, NMR spectra in conjunction with 2D experiments, COSY, HMQC and HMBC. The structural relationship of bartericins B and C was further established by the chemical cyclization of one to the other.

  19. Prenylated chalcones, flavone and other constituents of the twigs of Dorstenia angusticornis and Dorstenia barteri var. subtriangularis.

    PubMed

    Ngadjui, Bonaventure T; Watchueng, Jean; Keumedjio, Felix; Ngameni, Bathélémy; Simo, Ingrid K; Abegaz, Berhanu M

    2005-03-01

    The twigs of Dorstenia angusticornis and Dorstenia barteri var. subtriangularis yielded 16 compounds. Two novel diprenylated chalcones: 3,5'-di-(2-hydroxy-3-methylbut-3-enyl)-4,2',4'-trihydroxychalcone, 3, 4-(2,2-dimethylpyrano)-3'-(2-hydroxy-3-methylbut-3-enyl)-2',4'-dihydroxychalcone and the known stipulin were isolated from both species. 3-(2-Hydroxy-3-methylbut-3-enyl)-5'-(3,3-dimethylallyl)-4,2',4'-trihydroxychalcone and the known compounds: 4-hydroxylonchocarpin, kanzonol B, bartericins A, B, C and 3'-(2-hydroxy -3-methylbut-3-enyl)-4,2',4'-trihydroxychalcone were isolated from D. barteri while the known compounds: gancaonin Q, paratocarpins C, F, and lupeol were obtained from Dorstenia angusticornis. beta-Sitosterol and its beta-d-glucopyranoside were isolated from both species. Structures of these secondary metabolites were established using spectroscopic analysis, especially, NMR spectra in conjunction with 2D experiments, COSY, HMQC and HMBC.

  20. Structural elucidation of polysaccharide containing 3-O-methyl galactose from fruiting bodies of Pleurotus citrinopileatus.

    PubMed

    He, Pengfei; Zhang, Anqiang; Zhou, Saijing; Zhang, Fuming; Linhardt, Robert J; Sun, Peilong

    2016-11-03

    A water-soluble polysaccharide containing 3-O-methyl galactose (PCP60W) was isolated from fruiting bodies of Pleurotus citrinopileatus and purified by anion-exchange and gel column chromatography. This polysaccharide has an average molecular weight of 2.74 × 10 4  Da and its structure was elucidated using monosaccharide composition and methylation analysis combined with one- and two-dimensional (COSY, TOCSY, NOESY, HMQC and HMBC) NMR spectroscopy. PCP60W was shown to be a linear partially 3-O-methylated α-galactopyranan comprised of 6-linked galactose, 6-linked 3-O-methyl galactose and 4-linked glucose in a ratio of 3.0:1.0:0.6. This work provides additional evidence for the view that 3-O-methyl galactose is common to the genus Pleurotus. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Chemical of Vitex trifolia.

    PubMed

    Liu, Quan-Yu; Chen, Yong-Sheng; Wang, Fei; Chen, Shi-Wu; Zhang, Yong-Hong

    2014-06-01

    A new steroidal ester, beta-rosaterol palmitate (1) along with ten known compounds, uvaol(2), 3-epi-ursolic acid (3), 2alpha, 3beta, 24-trihydroxyolean-12-en-28-oic acid (4), 2alpha, 3alpha, 24-trihydroxyurs-12-en-28-oic acid (5), 2alpha, 3alpha, 24-trihydroxyolean-12-en-28-oic acid (6), 2alpha, 3alpha, 24-trihydroxyolean-12-en-28-oic acid-28-O-beta-D-glucopyranosyl ester (7), (Z)-9-hexadecenoic acid (8), octacosyl alcohol (9), beta-sitosterol (10) and beta-daucosterol (11), has been isolated from the stems and leaves of Vitex trifolia. Their structures were elucidated using a combination of 1D and 2D NMR techniques (COSY, HMQC, and HMBC)and HR-ESI-MS analyses. Compounds 2-7 were isolated from this plant for the first time.

  2. Synthesis, spectral and structural characterization of isobutyl 4-(2-chlorophenyl)-5-cyano-6-(((dimethylamino)methylene)amino)-2-methyl-4H-pyran-3-carboxylate

    NASA Astrophysics Data System (ADS)

    Udhaya Kumar, C.; Velayutham Pillai, M.; Gokula Krishnan, K.; Ramalingan, C.

    2017-09-01

    A fascinating selectivity in the direction of the formation of the formamidine was observed upon the reaction of isobutyl 6-amino-4-(2-chlorophenyl)-5-cyano-2-methyl-4H-pyran-3-carboxylate with N,N-dimethyl formamide. A development in selectivity is explored and a probable mechanism for the reaction is also proposed. The formamidine has been analyzed by FT-IR, FT-Raman, LC-MS and NMR (1D and 2D (1H-1H COSY, 1H-13C COSY and HMBC)) spectra. The experimental findings are compared with the theoretical data calculated by using DFT-B3LYP with 6-311++G(d,p) basis set. A good agreement has been observed between experimental and theoretical data. Single crystal X-ray structural analysis of isobutyl 4-(2-chlorophenyl)-5-cyano-6-(((dimethylamino)methylene)amino)-2-methyl-4H-pyran-3-carboxylate (PDMF), evidences the conformation of pyran ring as "flattened-boat".

  3. Constant-time 2D and 3D through-bond correlation NMR spectroscopy of solids under 60 kHz MAS

    PubMed Central

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2016-01-01

    Establishing connectivity and proximity of nuclei is an important step in elucidating the structure and dynamics of molecules in solids using magic angle spinning (MAS) NMR spectroscopy. Although recent studies have successfully demonstrated the feasibility of proton-detected multidimensional solid-state NMR experiments under ultrafast-MAS frequencies and obtaining high-resolution spectral lines of protons, assignment of proton resonances is a major challenge. In this study, we first re-visit and demonstrate the feasibility of 2D constant-time uniform-sign cross-peak correlation (CTUC-COSY) NMR experiment on rigid solids under ultrafast-MAS conditions, where the sensitivity of the experiment is enhanced by the reduced spin-spin relaxation rate and the use of low radio-frequency power for heteronuclear decoupling during the evolution intervals of the pulse sequence. In addition, we experimentally demonstrate the performance of a proton-detected pulse sequence to obtain a 3D 1H/13C/1H chemical shift correlation spectrum by incorporating an additional cross-polarization period in the CTUC-COSY pulse sequence to enable proton chemical shift evolution and proton detection in the incrementable t1 and t3 periods, respectively. In addition to through-space and through-bond 13C/1H and 13C/13C chemical shift correlations, the 3D 1H/13C/1H experiment also provides a COSY-type 1H/1H chemical shift correlation spectrum, where only the chemical shifts of those protons, which are bonded to two neighboring carbons, are correlated. By extracting 2D F1/F3 slices (1H/1H chemical shift correlation spectrum) at different 13C chemical shift frequencies from the 3D 1H/13C/1H spectrum, resonances of proton atoms located close to a specific carbon atom can be identified. Overall, the through-bond and through-space homonuclear/heteronuclear proximities determined from the 3D 1H/13C/1H experiment would be useful to study the structure and dynamics of a variety of chemical and biological

  4. The use of a selective saturation pulse to suppress t1 noise in two-dimensional (1)H fast magic angle spinning solid-state NMR spectroscopy.

    PubMed

    Robertson, Aiden J; Pandey, Manoj Kumar; Marsh, Andrew; Nishiyama, Yusuke; Brown, Steven P

    2015-11-01

    A selective saturation pulse at fast magic angle spinning (MAS) frequencies (60+kHz) suppresses t1 noise in the indirect dimension of two-dimensional (1)H MAS NMR spectra. The method is applied to a synthetic nucleoside with an intense methyl (1)H signal due to triisopropylsilyl (TIPS) protecting groups. Enhanced performance in terms of suppressing the methyl signal while minimising the loss of signal intensity of nearby resonances of interest relies on reducing spin diffusion--this is quantified by comparing two-dimensional (1)H NOESY-like spin diffusion spectra recorded at 30-70 kHz MAS. For a saturation pulse centred at the methyl resonance, the effect of changing the nutation frequency at different MAS frequencies as well as the effect of changing the pulse duration is investigated. By applying a pulse of duration 30 ms and nutation frequency 725 Hz at 70 kHz MAS, a good compromise of significant suppression of the methyl resonance combined with the signal intensity of resonances greater than 5 ppm away from the methyl resonance being largely unaffected is achieved. The effectiveness of using a selective saturation pulse is demonstrated for both homonuclear (1)H-(1)H double quantum (DQ)/single quantum (SQ) MAS and (14)N-(1)H heteronuclear multiple quantum coherence (HMQC) two-dimensional solid-state NMR experiments. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  5. Hplc-nmr identification of the human urinary metabolites of (-)-cis-5-fluoro-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl] cytosine, a nucleoside analogue active against human immunodeficiency virus (HIV).

    PubMed

    Shockcor, J P; Wurm, R M; Frick, L W; Sanderson, P N; Farrant, R D; Sweatman, B C; Lindon, J C

    1996-02-01

    1. Human urine samples from a clinical trial of the anti-HIV compound (-)-cis-5-fluoro-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl]-cyto sin e (BW524W91) have been analysed using 19F-nmr and 1H-hplc-nmr spectroscopy. 2. The identities and relative levels of the xenobiotic species in the urine have been determined by 470-MHz 19F-nmr spectroscopy and by directly coupled 600-MHz 1H-hplc-nmr in the stop-flow mode with confirmation of the metabolite identities being made by comparison with nmr spectra of synthetic standard compounds. 3. The principal urinary xenobiotic was the unchanged drug, but the glucuronide ether conjugate at the 5' position of BW524W91, one of the two diastereomeric sulphoxides and the deaminated metabolite were also characterized. 4. The detection limit of directly coupled hplc-600-MHz 1H-nmr spectroscopy was evaluated by measuring two-dimensional nmr spectra of the glucuronide conjugate of BW524W91 and shown to be approximately 1 microgram material for 1H-1H-TOCSY and 20 micrograms metabolite for 1H-13C-HMQC spectra for overnight (16 h) acquisition.

  6. The use of a selective saturation pulse to suppress t1 noise in two-dimensional 1H fast magic angle spinning solid-state NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Robertson, Aiden J.; Pandey, Manoj Kumar; Marsh, Andrew; Nishiyama, Yusuke; Brown, Steven P.

    2015-11-01

    A selective saturation pulse at fast magic angle spinning (MAS) frequencies (60+ kHz) suppresses t1 noise in the indirect dimension of two-dimensional 1H MAS NMR spectra. The method is applied to a synthetic nucleoside with an intense methyl 1H signal due to triisopropylsilyl (TIPS) protecting groups. Enhanced performance in terms of suppressing the methyl signal while minimising the loss of signal intensity of nearby resonances of interest relies on reducing spin diffusion - this is quantified by comparing two-dimensional 1H NOESY-like spin diffusion spectra recorded at 30-70 kHz MAS. For a saturation pulse centred at the methyl resonance, the effect of changing the nutation frequency at different MAS frequencies as well as the effect of changing the pulse duration is investigated. By applying a pulse of duration 30 ms and nutation frequency 725 Hz at 70 kHz MAS, a good compromise of significant suppression of the methyl resonance combined with the signal intensity of resonances greater than 5 ppm away from the methyl resonance being largely unaffected is achieved. The effectiveness of using a selective saturation pulse is demonstrated for both homonuclear 1H-1H double quantum (DQ)/single quantum (SQ) MAS and 14N-1H heteronuclear multiple quantum coherence (HMQC) two-dimensional solid-state NMR experiments.

  7. Identification of a novel structure in heparin generated by potassium permanganate oxidation

    PubMed Central

    Beccati, Daniela; Roy, Sucharita; Yu, Fei; Gunay, Nur Sibel; Capila, Ishan; Lech, Miroslaw; Linhardt, Robert J.; Venkataraman, Ganesh

    2012-01-01

    The worldwide heparin contamination crisis in 2008 led health authorities to take fundamental steps to better control heparin manufacture, including implementing appropriate analytical and bio-analytical methods to ensure production and release of high quality heparin sodium product. Consequently, there is an increased interest in the identification and structural elucidation of unusually modified structures that may be present in heparin. Our study focuses on the structural elucidation of species that give rise to a signal observed at 2.10 ppm in the N-acetyl region of the 1H NMR spectrum of some pharmaceutical grade heparin preparations. Structural elucidation experiments were carried out using homonuclear (COSY, TOSCY and NOESY) and heteronuclear (HSQC, HSQC-DEPT, HMQC-COSY, HSQC-TOCSY, and HMBC) 2D NMR spectroscopy on both heparin as well as heparin-like model compounds. Our results identify a novel type of oxidative modification of the heparin chain that results from a specific step in the manufacturing process used to prepare heparin. PMID:25147414

  8. Xenon-ion irradiation of Co/Si bilayers: Magnetic and structural properties

    NASA Astrophysics Data System (ADS)

    Novaković, M.; Popović, M.; Zhang, K.; Čubrović, V.; Bibić, N.; Rakočević, Z.

    2018-07-01

    Evolution of the structure of cobalt-silicon films during Xe ions irradiation has been studied and the same is correlated with magnetic properties. The polycrystalline cobalt films were deposited by electron beam evaporation method to a thickness of 50 nm on crystalline silicon (c-Si) and silicon with pre-amorphized surface (a-Si). After deposition the layers were irradiated with 400 keV Xe ions to the fluences in the range of 2-30 × 1015 ions/cm2. Structural analysis was done by means of transmission electron microscopy, atomic force microscopy (AFM) and X-ray diffraction (XRD), while the magnetic properties were analyzed by using magneto-optical Kerr effect (MOKE) technique. For the both types of substrate the AFM and XRD results show that after Xe ions irradiation the layers become more rough and the grain size of the crystallites increases; the effects being more evidenced for all fluences for the layers deposited on pre-amorphized Si. The MOKE measurements provided the in-plane azimuthal angular dependence of the hysteresis loops and the change of magnetization with the structural parameters. Although the coercive field is influenced by the surface roughness, in the case of c-Si substrate we found it is much more determined by the size of the crystallites. Additionally, independently on the substrate used the magnetic anisotropy in the Co films disappeared as the Xe ion fluence increased, indicating that the changes of magnetization in both systems occur for similar reasons.

  9. Localized 2D COSY sequences: Method and experimental evaluation for a whole metabolite quantification approach

    NASA Astrophysics Data System (ADS)

    Martel, Dimitri; Tse Ve Koon, K.; Le Fur, Yann; Ratiney, Hélène

    2015-11-01

    Two-dimensional spectroscopy offers the possibility to unambiguously distinguish metabolites by spreading out the multiplet structure of J-coupled spin systems into a second dimension. Quantification methods that perform parametric fitting of the 2D MRS signal have recently been proposed for resolved PRESS (JPRESS) but not explicitly for Localized Correlation Spectroscopy (LCOSY). Here, through a whole metabolite quantification approach, correlation spectroscopy quantification performances are studied. The ability to quantify metabolite relaxation constant times is studied for three localized 2D MRS sequences (LCOSY, LCTCOSY and the JPRESS) in vitro on preclinical MR systems. The issues encountered during implementation and quantification strategies are discussed with the help of the Fisher matrix formalism. The described parameterized models enable the computation of the lower bound for error variance - generally known as the Cramér Rao bounds (CRBs), a standard of precision - on the parameters estimated from these 2D MRS signal fittings. LCOSY has a theoretical net signal loss of two per unit of acquisition time compared to JPRESS. A rapid analysis could point that the relative CRBs of LCOSY compared to JPRESS (expressed as a percentage of the concentration values) should be doubled but we show that this is not necessarily true. Finally, the LCOSY quantification procedure has been applied on data acquired in vivo on a mouse brain.

  10. Elemental and Microscopic Analysis of Naturally Occurring C-O-Si Hetero-Fullerene-Like Structures.

    PubMed

    Hullavarad, Nilima V; Hullavarad, Shiva S; Fochesatto, Javier

    2015-03-01

    Carbon exhibits an ability to form a wide range of structures in nature. Under favorable conditions, carbon condenses to form hollow, spheroid fullerenes in an inert atmosphere. Using high resolution FESEM, we have concealed the existence of giant hetero-fullerene like structures in the natural form. Clear, distinct features of connected hexagons and pentagons were observed. Energy dispersive X-ray analysis depth-profile of natural fullerene structures indicates that Russian-doll-like configurations composed of C, 0, and Si rings exist in nature. The analysis is based on an outstanding molecular feature found in the size fraction of aerosols having diameters 150 nm to 1.0 µm. The fullerene like structures, which are ~ 150 nm in diameter, are observed in large numbers. To the best of our knowledge, this is the first direct detailed observation of natural fullerene-like structures. This article reports inadvertent observation of naturally occurring hetero-fullerene-like structures in the Arctic.

  11. Complete structure of the cell surface polysaccharide of Streptococcus oralis ATCC 10557: A receptor for lectin-mediated interbacterial adherence

    SciTech Connect

    Abeygunawardana, C.; Bush, C.A.; Cisar, J.O.

    1991-07-02

    Lectin-carbohydrate binding is known to play an important role in a number of different cell-cell interactions including those between certain species of oral streptococci and actinomyces that colonize teeth. The cell wall polysaccharides of Streptococcus oralis ATCC 10557, S. oralis 34, and Streptococcus mitis J22, although not identical antigenically, each function as a receptor molecule for the galactose and N-acetylgalactosamine reactive fimbrial lectins of Actinomyces viscosus and Actinomyces naeslundii. Carbohydrate analysis of the receptor polysaccharide isolated from S. oralis ATCC 10557 shows galactose (3 mol), glucose (1 mol), GalNAc (1 mol), and rhamnose (1 mol). {sup 1}H NMR spectra ofmore » the polysaccharide show that is partially O-acetylated. Analysis of the {sup 1}H NMR spectrum of the de-O-acetylated polysaccharide shows that it is composed of repeating subunits containing six monosaccharides and that the subunits are joined by a phosphodiester linkage. The {sup 1}H and {sup 13}C NMR spectra were completely assigned by two-dimensional homonuclear correlation methods and by {sup 1}H-detected heteronuclear multiple-quantum correlation ({sup 1}H({sup 13}C)HMQC). The complete {sup 1}H and {sup 13}C assignment of the native polysaccharide was carried out by the same techniques augmented by a {sup 13}C-coupled hybrid HMQC-COSY method, which is shown to be especially useful for carbohydrates in which strong coupling and overlapping peaks in the {sup 1}H spectrum pose difficulties.« less

  12. Ruthenium(II) bipyridine complexes bearing new keto-enol azoimine ligands: synthesis, structure, electrochemistry and DFT calculations.

    PubMed

    Al-Noaimi, Mousa; Awwadi, Firas F; Mansi, Ahmad; Abdel-Rahman, Obadah S; Hammoudeh, Ayman; Warad, Ismail

    2015-01-25

    The novel azoimine ligand, Ph-NH-N=C(COCH3)-NHPh(C≡CH) (H2L), was synthesized and its molecular structure was determined by X-ray crystallography. Catalytic hydration of the terminal acetylene of H2L in the presence of RuCl3·3H2O in ethanol at reflux temperature yielded a ketone (L1=Ph-N=N-C(COCH3)=N-Ph(COCH3) and an enol (L2=Ph-N=N-C(COCH3)=N-PhC(OH)=CH2) by Markovnikov addition of water. Two mixed-ligand ruthenium complexes having general formula, trans-[Ru(bpy)(Y)Cl2] (1-2) (where Y=L1 (1) and Y=L2 (2), bpy is 2.2'-bipyrdine) were achieved by the stepwise addition of equimolar amounts of (H2L) and bpy ligands to RuCl3·3H2O in absolute ethanol. Theses complexes were characterized by elemental analyses and spectroscopic (IR, UV-Vis, and NMR (1D (1)H NMR, (13)C NMR, (DEPT-135), (DEPT-90), 2D (1)H-(1)H and (13)C-(1)H correlation (HMQC) spectroscopy)). The two complexes exhibit a quasi-reversible one electron Ru(II)/Ru(III) oxidation couple at 604 mV vs. ferrocene/ferrocenium (Cp2Fe(0/+)) couple along with one electron ligand reduction at -1010 mV. The crystal structure of complex 1 showed that the bidentate ligand L1 coordinates to Ru(II) by the azo- and imine-nitrogen donor atoms. The complex adopts a distorted trans octahedral coordination geometry of chloride ligands. The electronic spectra of 1 and 1+ in dichloromethane have been modeled by time-dependent density functional theory (TD-DFT). Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Synthesis and characterization of chitosan alkyl urea.

    PubMed

    Wang, Jing; Jiang, Ji-Zhou; Chen, Wei; Bai, Zheng-Wu

    2016-07-10

    Chitosan is a versatile material employed for various purposes in many fields including the development of chiral stationary phases for enantioseparation. Chitosan alkyl urea is a kind of intermediate used to prepare enantioseparation materials. In order to synthesize the intermediates, in the present work, a new way to prepare chitosan alkyl urea has been established: chitosan was first reacted with methyl chloroformate yielding N-methoxyformylated chitosan, which was then converted to chitosan alkyl urea through amine-ester exchange reaction. With a large excess of methyl chloroformate and primary amine of low stereohindrance, the amino group in chitosan could be almost completely converted to ureido group. The as-prepared chitosan alkyl urea derivatives were characterized by IR, (1)H NMR, (13)C NMR,(1)H-(1)H COSY and (1)H-(13)C HSQC NMR spectra. The chemical shifts of hydrogen and carbon atoms of glucose unit were assigned. It was found that the degree of substitution was obviously lower if cyclopropyl amine, aniline, tert-butyl amine and diethyl amine were used as reactants for the amine-ester exchange reaction. The reason was explained with the aid of theoretical calculations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Liquid- and solid-state high-resolution NMR methods for the investigation of aging processes of silicone breast implants.

    PubMed

    Birkefeld, Anja Britta; Bertermann, Rüdiger; Eckert, Hellmut; Pfleiderer, Bettina

    2003-01-01

    To investigate aging processes of silicone gel breast implants, which may include migration of free unreacted material from the gel and rubber to local (e.g. connective tissue capsule) or distant sites in the body, chemical alteration of the polymer and infiltration of body compounds, various approaches of multinuclear nuclear magnetic resonance (NMR) experiments (29Si, 13C, 1H) were evaluated. While 29Si, 13C, and 1H solid-state magic angle spinning (MAS) NMR techniques performed on virgin and explanted envelopes of silicone prostheses provided only limited information, high-resolution liquid-state NMR techniques of CDCl(3) extracts were highly sensitive analytical tools for the detection of aging related changes in the materials. Using 2D 1H, 1H correlation spectroscopy (COSY) and 29Si, 1H heteronuclear multiple bond coherence (HMBC) experiments with gradient selection, it was possible to detect lipids (mainly phospholipids) as well as silicone oligomer species in explanted envelopes and gels. Silicone oligomers were also found in connective tissue capsules, indicating that cyclic polysiloxanes can migrate from intact implants to adjacent and distant sites. Furthermore, lipids can permeate the implant and modify its chemical composition. Copyright 2002 Elsevier Science Ltd.

  15. Determination of astaxanthin and astaxanthin esters in the microalgae Haematococcus pluvialis by LC-(APCI)MS and characterization of predominant carotenoid isomers by NMR spectroscopy.

    PubMed

    Holtin, Karsten; Kuehnle, Maximilian; Rehbein, Jens; Schuler, Paul; Nicholson, Graeme; Albert, Klaus

    2009-11-01

    The oily product ZANTHIN consists of natural astaxanthin, which is manufactured from the microalgae Haematococcus pluvialis by supercritical CO(2) extraction. An HPLC method was developed to separate all of the components of the complex astaxanthin extract using a C(30) column. The separation resulted in different isomers of astaxanthin accompanied by two other carotenoids. The main component consisted of astaxanthin singly esterified with several different fatty acids. C18:3, C18:2, C18:1 and C16:0 were identified as the most commonly occurring fatty acids. Doubly esterified astaxanthin was also found, although in lower concentrations compared to singly esterified astaxanthin. After performing a detailed fatty acid analysis by GC-MS, the peaks from the extract were assigned via HPLC-MS. A trans to cis transmutation of the all-trans compound was performed by thermal treatment in order to obtain an enrichment of cis isomers as the basis for unambiguous identification via NMR experiments. The all-trans as well as the 9- and 13-cis isomers of astaxanthin were characterized in detail by UV/Vis, (1)H, and (1)H,(1)H COSY NMR spectroscopy.

  16. A definitive analytical spectroscopic study of Indian yellow, an ancient pigment used for dating purposes.

    PubMed

    de Faria, Dalva L A; Edwards, Howell G M; Careaga, Valeria; Walt, Nicholas; Maier, Marta S

    2017-02-01

    The Raman spectrum of tartrazine has been mistakenly reported as being that of Indian yellow in the literature, which has serious consequences for the identification of this pigment in art works regarding their authentication. Unlike tartrazine, Indian yellow (a natural mixture of the magnesium and calcium salts of euxanthic acid) exhibits in its Raman spectrum a strong fluorescent background when visible excitation is used, however, excitation in the near infrared (1064nm) permitted the observation of the Raman bands from the raw pigment with the main features placed at 1346, 1368, 1425, 1441 and 1626cm -1 . Indian yellow identification was assured by 1 H and 13 C Nuclear Magnetic Resonance characterization and the complete assignment of the proton and carbon resonances was accomplished using heteronuclear single quantum correlation (HSQC), heteronuclear multiple bond correlation (HMBC), nuclear overhauser effect spectroscopy (NOESY) and 1 H- 1 H correlation spectroscopy (COSY). Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and X-ray fluorescence (XRF) analyzes were also conducted on a genuine sample of this historical pigment. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. One pot synthesis of Curcumin-NSAIDs prodrug, spectroscopic characterization, conformational analysis, chemical reactivity, intramolecular interactions and first order hyperpolarizability by DFT method

    NASA Astrophysics Data System (ADS)

    Srivastava, Sangeeta; Gupta, Preeti; Sethi, Arun; Singh, Ranvijay Pratap

    2016-08-01

    A novel Curcumin-NSAIDs prodrug 4-((1E, 3Z, 6E)-3-hydroxy-(4-hydroxy-3-methoxyphenyl)-5-oxohepta-1,3,3-trienyl)-2-methoxyphenyl-2-(4-isobutylphenyl) propanoate (2) derivative was synthesized by Steglich esterification in high yield and characterized with the help of 1H, 13C NMR, 1H-1H COSY, UV, FT-IR spectroscopy and mass spectrometry. The molecular geometry of synthesized compound was calculated in ground state by Density functional theory (DFT/B3LYP) using two different basis set 6-31G (d, p) and 6-311G (d, p). Conformational analysis of 2 was carried out to determine the most stable conformation. Stability of the molecule as a result of hyperconjugative interactions and electron delocalization were analysed using Natural bond orbital (NBO) analysis. Intramolecular interactions were analysed by AIM (Atom in molecule) approach. Global and local reactivity descriptors were calculated to study the reactive site within molecule. The electronic properties such as HOMO and LUMO energies were calculated using time dependent Density Functional Theory (TD-DFT). The vibrational wavenumbers were calculated using DFT method and assigned with the help of potential energy distribution (PED). First hyperpolarizability value has been calculated to describe the nonlinear optical (NLO) property of the synthesized compound. Molecular electrostatic potential (MEP) for synthesized compounds have also been determined to check their electrophilic or nucleophilic reactivity.

  18. Odisolane, a Novel Oxolane Derivative, and Antiangiogenic Constituents from the Fruits of Mulberry (Morus alba L.).

    PubMed

    Lee, Seoung Rak; Park, Jun Yeon; Yu, Jae Sik; Lee, Sung Ok; Ryu, Ja-Young; Choi, Sang-Zin; Kang, Ki Sung; Yamabe, Noriko; Kim, Ki Hyun

    2016-05-18

    Mulberry, the fruit of Morus alba L., is known as an edible fruit and commonly used in Chinese medicines as a warming agent and as a sedative, tonic, laxative, odontalgic, expectorant, anthelmintic, and emetic. Systemic investigation of the chemical constituents of M. alba fruits led to the identification of a novel oxolane derivative, (R*)-2-((2S*,3R*)-tetrahydro-2-hydroxy-2-methylfuran-3-yl)propanoic acid (1), namely, odisolane, along with five known heterocyclic compounds (2-6). The structure of the new compound was elucidated on the basis of HR-MS, 1D and 2D NMR ((1)H-(1)H COSY, HSQC, HMBC, and NOESY) data analysis. Compound 1 has a novel skeleton that consists of 8 carbon units with an oxolane ring, which until now has never been identified in natural products. The isolated compounds were subjected to several activity tests to verify their biological function. Among them, compounds 1, 3, and 5 significantly inhibited cord formation in HUVECs. The action mechanism of compound 3, which had the strongest antiangiogenic activity, was mediated by decreasing VEGF, p-Akt, and p-ERK protein expression. These results suggest that compounds isolated from M. alba fruits might be beneficial in antiangiogenesis therapy for cancer treatment.

  19. A new flavonol glycoside from the medicinal halophyte Suaeda fruticosa.

    PubMed

    Oueslati, Samia; Ksouri, Riadh; Pichette, André; Lavoie, Serge; Girard-Lalancette, Karl; Mshvildadze, Vakhtang; Abdelly, Chedly; Legault, Jean

    2014-01-01

    A new flavonol glycoside, namely 3-(α-rhamnopyranosyl-(1 → 2)-[β-xylopyranosyl-(1 → 6)]-β-glucopyranosyloxy) isorhamnetin was reported from methanol extracts of aerial parts of Suaeda fruticosa for the first time. In this work, liquid chromatography coupled to atmospheric pressure chemical ionisation mass spectrometry, high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy were used to identify this new compound. Structure was elucidated on the basis of extensive spectroscopic analysis, including HSQC, HMBC and (1)H-(1)H COSY. Antioxidant potentialities of a pure compound were evaluated. The estimation of antioxidant capacities using oxygen radical absorbance capacity (ORAC method) and a cell based-assay (WS1) indicated that this new flavonol exhibited the highest antioxidant activities with an ORAC value of 5.0 ± 0.3 μmol Trolox/μmol and inhibited the tBH-induced oxidation of 2',7'-dichlorofluorescin with an IC50 value of 4.9 ± 0.6 μM.

  20. Structural studies of an arabinan from the stems of Ephedra sinica by methylation analysis and 1D and 2D NMR spectroscopy.

    PubMed

    Xia, Yong-Gang; Liang, Jun; Yang, Bing-You; Wang, Qiu-Hong; Kuang, Hai-Xue

    2015-05-05

    Plant arabinan has important biological activity. In this study, a water-soluble arabinan (Mw∼6.15kDa) isolated from the stems of Ephedra sinica was found to consist of (1→5)-Araƒ, (1→3,5)-Araƒ, T-Araƒ, (1→3)-Araƒ and (1→2,5)-Araƒ residues at proportions of 10:2:3:2:1. A tentative structure was proposed by methylation analysis, nuclear magnetic resonance (NMR) spectroscopy ((1)H NMR, (13)C NMR, DEPT-135, (1)H-(1)H COSY, HSQC, HMBC and ROESY) and literature. The structure proposed includes a branched (1→5)-α-Araf backbone where branching occurs at the O-2 and O-3 positions of the residues with 7.7% and 15.4% of the 1,5-linked α-Araf substituted at the O-2 and O-3 positions. The presence of a branched structure was further observed by atomic force microscopy. This polymer was characterized as having a much longer linear (1→5)-α-Araf backbone as a repeating unit. In particular, the presence of α-Araf→3)-α-Araf-(1→3)-α-Araf-(1→ attached at the O-2 is a new finding. This study may facilitate a deeper understanding of structure-activity relationships of biological polysaccharides from the stems of E. sinica. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Bioactive phenylpropanoid analogues from Piper betle L. var. birkoli leaves.

    PubMed

    Atiya, Akhtar; Sinha, Barij Nayan; Lal, Uma Ranjan

    2017-11-01

    Phytochemical analyses of the chloroform extract of Piper betle L. var. birkoli, Piperaceae, leaves led to the isolation of two new phenylpropanoid analogues: bis-chavicol dodecanoyl ester (2) and bis-hydroxychavicol dodecanoyl ester (3), along with one known compound: allyl-3-methoxy-4-hydroxybenzene (1) on the basis of spectroscopic data 1D ( 1 H and 13 C) and 2D ( 1 H- 1 H COSY and HMBC) NMR, as well as ESI-MS, FT-IR, HR-ESI-MS and LC-ESI-MS. Compound 2 and 3 exhibited excellent antioxidant DPPH radical scavenging activity with IC 50 values of 12.67 μg/mL and 1.08 μg/mL compared to ascorbic acid as a standard antioxidant drug with IC 50 value of 6.60 μg/mL. Evaluation of cytotoxic activity against two human oral cancer cell lines (AW13516 and AW8507) showed significant effect with GI 50 values of 19.61 and 23.01 μg/mL for compound 2 and 10.25 and 13.12 μg/mL for compound 3, compared to Doxorubicin ® as a standard cytotoxic drug with GI 50 value of < 10 μg/mL.

  2. New chemical constituents from the Piper betle Linn. (Piperaceae).

    PubMed

    Atiya, Akhtar; Sinha, Barij Nayan; Ranjan Lal, Uma

    2018-05-01

    The phytochemical investigation of chloroform extract from Piper betle var. haldia, Piperaceae, leaves has resulted in the isolation of two new chemical constituents which were identified as 1-n-dodecanyloxy resorcinol (H1) and desmethylenesqualenyl deoxy-cepharadione-A (H4), on the basis of spectroscopic data 1D NMR ( 1 H and 13 C) and 2D NMR ( 1 H- 1 H COSY and HMBC) as well as ESI-MS, FT-IR and HR-ESI-MS analyses. Compounds H1 and H4 showed excellent antioxidant DPPH free radical scavenging activity with IC 50 values of 7.14 μg/mL and 8.08 μg/mL compared to ascorbic acid as a standard antioxidant drug with IC 50 value of 2.52 μg/mL, respectively. Evaluation of cytotoxic activity against human hepatoma cell line (PLC-PRF-5) showed moderate effect with the GI 50 values of 35.12 μg/mL for H1, 31.01 μg/mL for H4, compared to Doxorubicin ® as a standard cytotoxic drug with GI 50 value of 18.80 μg/mL.

  3. A new anthraquinone and eight constituents from Hedyotis caudatifolia Merr. et Metcalf: isolation, purification and structural identification.

    PubMed

    Luo, Peng; Su, Jiale; Zhu, Yilin; Wei, Jianhua; Wei, Wanxing; Pan, Weigao

    2016-10-01

    Hedyotis caudatifolia Merr. et Metcalf. (HC), a folk medicine in Yao nationalities areas in China, was used to investigate the chemical constituents. Through silica gel and Sephadex LH-20 column chromatography, nine compounds were isolated and purified. By physical and chemical properties, IR, MS (EI-MS, high resolution EI-MS), 1D NMR ((1)H NMR, (13)C NMR) and 2D NMR (HSQC, (1)H-(1)H COSY, HMBC), their structures were identified as β-sitosterol (1), stigmasterol (2), scopolin (3), 2-hydroxy-1,7,8-trimethoxyanthracene-9,10-dione (4), oleanolic acid (5), ursolic acid (6), methyl barbinervate (7), β-daucosterol (8) and p-Hydroxybenzoic acid (9). These compounds were isolated from HC for the first time, and 4 a new anthraquinone whose biological activities are worth to be investigated in future. These compounds may contribute to the HC's pharmacological effects on treating diseases, and may be used as candidates for control index in establishing the quality control standard of HC.

  4. Cytotoxic Triterpenoids from the Stalks of Microtropis triflora.

    PubMed

    Zhang, Xiao-Wei; Wang, Kui-Wu; Zhou, Man-Qing

    2017-07-01

    Bioassay-guided phytochemical investigation of the stalks of Microtropis triflora Merr. & F.L. Freeman led to the isolation of ten triterpenes 1 - 10, including one novel compound 3,24-epoxy-2α,24-dihydroxyfriedelan-29-oic acid (1). Their chemical structures were identified on the basis of spectroscopic analysis, including HR-ESI mass spectrometry, 1D- and 2D-NMR ( 1 H, 13 C, 1 H, 1 H-COSY, HSQC, HMBC, and NOESY), and by comparison with the data reported. The cytotoxicities of compounds 1 - 10 against a panel of cultured human tumor cell lines (Bcap37, SMMC7721, HeLa, CNE) were evaluated. The new compound 1 showed moderate anti-tumor activities with IC 50 values of 39.22, 29.24, 23.28, and 68.81 μm/ml, respectively. These results might be helpful for explaining the use of M. triflora in traditional medicine. Triterpenes are characteristic of Microtropis genus and could be useful as potential chemotaxonomic markers. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

  5. Synthesis of 21,23-selenium- and tellurium-substituted 5-porphomethenes, 5,10-porphodimethenes, 5,15-porphodimethenes, and porphotrimethenes and their interactions with mercury.

    PubMed

    Ahmad, Sohail; Yadav, Kumar Karitkey; Bhattacharya, Soumee; Chauhan, Prashant; Chauhan, S M S

    2015-04-17

    The 3+1 condensation of symmetrical 16-Selena/telluratripyrranes with symmetrical selenophene-2,5-diols/tellurophene-2,5-diols in the presence of BF3-etheratre or BF3-methanol followed by oxidation with DDQ gave 5,10-porphodimethenes, whereas the process with unsymmetrical selenophene-2,5-diols/tellurophene-2,5-diols gave 5-porphomethenes. In addition, the reaction of unsymmetrical 16-Selena/telluratripyrranes with symmetrical selenophene-2,5-diols/tellurophene-2,5-diols gave the corresponding porphotrimethenes, whereas the process with unsymmetrical selenophene-2,5-diols/tellurophene-2,5-diols gave the 5,15-porphodimethenes. The structures of different products were characterized by IR, (1)H and (13)C NMR, (1)H-(1)H COSY, CHN analysis, and mass spectrometry. The binding of mercury with the calix[4]phyrins mentioned above had been observed in the decreasing order of porphodimethenes > porphomethenes > porphotrimethenes by UV-vis and (1)H NMR spectroscopy.

  6. Spectroscopic, electrochemical and photovoltaic properties of Pt(ii) and Pd(ii) complexes of a chelating 1,10-phenanthroline appended perylene diimide.

    PubMed

    Işık Büyükekşi, Sebile; Şengül, Abdurrahman; Erdönmez, Seda; Altındal, Ahmet; Orman, Efe Baturhan; Özkaya, Ali Rıza

    2018-02-20

    In this study, a bis-chelating bridging perylene diimide ditopic ligand, namely N,N'-di(1,10-phenanthroline)-1,6,7,12-tetrakis-(4-methoxyphenoxy)perylene tetracarboxylic acid diimide (1), was synthesized and characterized. Further reactions of 1 with d 8 metal ions such as Pt(ii) and Pd(ii) having preferential square-planar geometry afforded the novel triads [(Cl 2 )M(ii)-(1)-M(ii)(Cl 2 )] where M(ii) = Pt(ii) (2), and Pd(ii) (3), respectively. The isolated triads and the key precursor were fully characterized by FT-IR, 1D-NMR ( 1 H NMR and 13 C DEPT NMR), 2D-NMR ( 1 H- 1 H COSY, 1 H- 13 C HSQC, 1 H- 13 C HMBC), MALDI-TOF mass and UV/Vis spectroscopy. The electrochemical properties of 1, 2 and 3 were investigated by cyclic voltammetry as well as in situ spectroelectrochemistry and also in situ electrocolorimetric measurements. These compounds were shown to exhibit net colour changes suitable for electrochromic applications. The compounds exhibited remarkably narrow HOMO-LUMO gaps, leading to their ease of reduction at low negative potentials. More importantly, dye-sensitized solar cells (DSSCs) were also fabricated using 1-3 to clarify the potential use of these complexes as a sensitizer. Analysis of the experimental data indicated that 2 has good potential as a sensitizer material for DSSCs.

  7. Use of NMR-Based Metabolomics To Chemically Characterize the Roasting Process of Chicory Root.

    PubMed

    Wei, Feifei; Furihata, Kazuo; Zhang, Mimin; Miyakawa, Takuya; Tanokura, Masaru

    2016-08-16

    Roasted chicory root (Cichorium intybus) has been widely accepted as the most important coffee substitute. In this study, a nuclear magnetic resonance (NMR)-based comprehensive analysis was performed to monitor the substantial changes in the composition of chicory root during the roasting process. A detailed signal assignment of dried raw and roasted chicory roots was carried out using 1 H, 13 C, 1 H- 1 H DQF-COSY, 1 H- 13 C edited-HSQC, 1 H- 13 C CT-HMBC, and 1 H- 13 C HSQC-TOCSY NMR spectra. On the basis of the signal assignments, 36 NMR-visible components were monitored simultaneously during roasting. Inulins, sucrose, and most of the amino acids were largely degraded during the roasting process, whereas monosaccharides decreased at the beginning and then increased until the dark roasting stage. Acetamide, 5-hydroxymethylfurfural, di-d-fructose dianhydride, and norfuraneol were newly formed during roasting. Furthermore, a principal component analysis score plot indicated that similar chemical composition profiles could be achieved by roasting the chicory root either at a higher firepower for a shorter time or at a lower firepower for a longer time.

  8. The structure and immunoreactivity of exopolysaccharide isolated from Lactobacillus johnsonii strain 151.

    PubMed

    Górska-Frączek, Sabina; Sandström, Corine; Kenne, Lennart; Paściak, Mariola; Brzozowska, Ewa; Strus, Magdalena; Heczko, Piotr; Gamian, Andrzej

    2013-08-30

    The exopolysaccharide (EPS) structure from Lactobacillus johnsonii strain 151 isolated from the intestinal tract of mice was investigated. Sugar and methylation analyses together with (1)H and (13)C NMR spectroscopy, including two-dimensional (1)H,(1)H COSY, TOCSY, NOESY, and (1)H,(13)C HSQC, HMBC experiments, revealed that the repeating unit of the EPS is the linear pentasaccharide: →6)-α-d-Galp-(1→6)-α-d-Glcp-(1→3)-β-d-Galf-(1→3)-α-d-Glcp-(1→2)-β-d-Galf-(1→ The immunoreactivity of two structurally different exopolysaccharides isolated from L. johnsonii, 151 and 142 (Carbohydr. Res. 2010, 345, 108-114), was compared. Both EPSs differed in their reactivity with antisera. EPS from L. johnsonii 151 reacted with anti-Lactobacillus polyclonal sera against cells of five different strains, while EPS from L. johnsonii 142 was found to react only with its own antiserum. The broader specificity and higher reactivity of EPS from 151 strain than EPS from 142 strain were also observed with human sera. The physiological antibodies recognizing polysaccharide antigens were present in both adults and umbilical cord blood sera. A highly specific EPS 142 bearing strain was isolated from experimentally induced inflammatory bowel disease (IBD) mice, while a strain with EPS 151 isolated from the intestinal tract of healthy mice is characterized by a broad immune reactivity common structure. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Metal complexes of a new potentially heptadentate(N 7) tripodal Schiff base ligand. Synthesis, NMR studies and ab initio calculations

    NASA Astrophysics Data System (ADS)

    Salehzadeh, Sadegh; Javarsineh, Seyed Amrollah; Keypour, Hassan

    2006-03-01

    Tris(3-aminopropyl)amine, 2-pyridinecarboxaldehyde and a number of metal ions were used to prepare metal complexes of a new fully condensed potentially heptadentate(N 7) tripodal Schiff base ligand (L 333). The resulting complexes, [M(L 333)](ClO 4) 2 {M= Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II); L 333=[N(CH 2CH 2CH 2N dbnd6 CH(C 5H 4N)) 3]}, were characterized by microanalysis, IR and electronic spectra in all cases and by NMR spectra in the case of Zn(II) and Cd(II) complexes: these two are both seven-co-ordinate. The 1H NMR, COSY and HMQC spectra of these complexes show two kinds of protons for each methylene group. The COSY spectrum confirms the geminal coupling of the two protons of each methylene group, indicating that the protons are diastereotopic in rigid six-membered rings. In the 1H NMR spectrum of the cadmium complex the signal of the imine proton has two clear satellites peaks ( 3J=41.9 Hz) with intensities in the ratio 1:6:1 due to coupling with neighbouring 111/113Cd. This coupling constant was confirmed by 113Cd NMR spectroscopy. Ab initio studies on [Fe(L 333)] 2+, [Zn(L 333)] 2+ and [Cd(L 333)] 2+ and also on the previously known complex, [Cd(L Me333)] 2+ are also reported. The results show that the shortest bonding interaction between the metal ion and the bridging tertiary nitrogen atom of the ligand is occurs in the Cd(II) complexes.

  10. Determination of size and sign of hetero-nuclear coupling constants from 2D 19F-13C correlation spectra.

    PubMed

    Ampt, Kirsten A M; Aspers, Ruud L E G; Dvortsak, Peter; van der Werf, Ramon M; Wijmenga, Sybren S; Jaeger, Martin

    2012-02-01

    Fluorinated organic compounds have become increasingly important within the polymer and the pharmaceutical industry as well as for clinical applications. For the structural elucidation of such compounds, NMR experiments with fluorine detection are of great value due to the favorable NMR properties of the fluorine nucleus. For the investigation of three fluorinated compounds, triple resonance 2D HSQC and HMBC experiments were adopted to fluorine detection with carbon and/or proton decoupling to yield F-C, F-C{H}, F-C{C(acq)} and F-C{H,C(acq)} variants. Analysis of E.COSY type cross-peak patterns in the F-C correlation spectra led, apart from the chemical shift assignments, to determination of size and signs of the J(CH), J(CF), and J(HF) coupling constants. In addition, the fully coupled F-C HMQC spectrum of steroid 1 was interpreted in terms of E.COSY type patterns. This example shows how coupling constants due to different nuclei can be determined together with their relative signs from a single spectrum. The analysis of cross-peak patterns, as presented here, not only provides relatively straightforward routes to the determination of size and sign of hetero-nuclear J-couplings in fluorinated compounds, it also provides new and easy ways for the determination of residual dipolar couplings and thus for structure elucidation. The examples and results presented in this study may contribute to a better interpretation and understanding of various F-C correlation experiments and thereby stimulate their utilization. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Socioeconomic inequalities in childhood overweight: heterogeneity across five countries in the WHO European Childhood Obesity Surveillance Initiative (COSI-2008).

    PubMed

    Lissner, L; Wijnhoven, T M A; Mehlig, K; Sjöberg, A; Kunesova, M; Yngve, A; Petrauskiene, A; Duleva, V; Rito, A I; Breda, J

    2016-05-01

    Excess risk of childhood overweight and obesity occurring in socioeconomically disadvantaged families has been demonstrated in numerous studies from high-income regions, including Europe. It is well known that socioeconomic characteristics such as parental education, income and occupation are etiologically relevant to childhood obesity. However, in the pan-European setting, there is reason to believe that inequalities in childhood weight status may vary among countries as a function of differing degrees of socioeconomic development and equity. In this cross-sectional study, we have examined socioeconomic differences in childhood obesity in different parts of the European region using nationally representative data from Bulgaria, the Czech Republic, Lithuania, Portugal and Sweden that were collected in 2008 during the first round of the World Health Organization (WHO) European Childhood Obesity Surveillance Initiative. Heterogeneity in the association between parental socioeconomic indicators and childhood overweight or obesity was clearly observed across the five countries studied. Positive as well as negative associations were observed between parental socioeconomic indicators and childhood overweight, with statistically significant interactions between country and parental indicators. These findings have public health implications for the WHO European Region and underscore the necessity to continue documenting socioeconomic inequalities in obesity in all countries through international surveillance efforts in countries with diverse geographic, social and economic environments. This is a prerequisite for universal as well as targeted preventive actions.

  12. Materials Data on Na2Co(Si2O5)2 (SG:2) by Materials Project

    DOE Data Explorer

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  13. Constituents of Musa x paradisiaca cultivar with the potential to induce the phase II enzyme, quinone reductase.

    PubMed

    Jang, Dae Sik; Park, Eun Jung; Hawthorne, Michael E; Vigo, Jose Schunke; Graham, James G; Cabieses, Fernando; Santarsiero, Bernard D; Mesecar, Andrew D; Fong, Harry H S; Mehta, Rajendra G; Pezzuto, John M; Kinghorn, A Douglas

    2002-10-23

    A new bicyclic diarylheptanoid, rel-(3S,4aR,10bR)-8-hydroxy-3-(4-hydroxyphenyl)-9-methoxy-4a,5,6,10b-tetrahydro-3H-naphtho[2,1-b]pyran (1), as well as four known compounds, 1,2-dihydro-1,2,3-trihydroxy-9-(4-methoxyphenyl)phenalene (2), hydroxyanigorufone (3), 2-(4-hydroxyphenyl)naphthalic anhydride (4), and 1,7-bis(4-hydroxyphenyl)hepta-4(E),6(E)-dien-3-one (5), were isolated from an ethyl acetate-soluble fraction of the methanol extract of the fruits of Musa x paradisiaca cultivar, using a bioassay based on the induction of quinone reductase (QR) in cultured Hepa1c1c7 mouse hepatoma cells to monitor chromatographic fractionation. The structure and relative stereochemistry of compound 1 were elucidated unambiguously by one- and two-dimensional NMR experiments ((1)H NMR, (13)C NMR, DEPT, COSY, HMQC, HMBC, and NOESY) and single-crystal X-ray diffraction analysis. Isolates 1-5 were evaluated for their potential cancer chemopreventive properties utilizing an in vitro assay to determine quinone reductase induction and a mouse mammary organ culture assay.

  14. Chemical constituents from Tribulus terrestris and screening of their antioxidant activity.

    PubMed

    Hammoda, Hala M; Ghazy, Nabila M; Harraz, Fathalla M; Radwan, Mohamed M; ElSohly, Mahmoud A; Abdallah, Ingy I

    2013-08-01

    Two oligosaccharides (1,2) and a stereoisomer of di-p-coumaroylquinic acid (3) were isolated from the aerial parts of Tribulus terrestris along with five known compounds (4-8). The structures of the compounds were established as O-β-D-fructofuranosyl-(2→6)-α-D-glucopyranosyl-(1→6)-β-D-fructofuranosyl-(2→6)-β-D-fructofuranosyl-(2→1)-α-D-glucopyranosyl-(6→2)-β-D-fructofuranoside (1), O-α-D-glucopyranosyl-(1→4)-α-D-glucopyranosyl-(1→4)-α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside (2), 4,5-di-p-cis-coumaroylquinic acid (3) by different spectroscopic methods including 1D NMR ((1)H, (13)C and DEPT) and 2D NMR (COSY, TOCSY, HMQC and HMBC) experiments as well as ESI-MS analysis. This is the first report for the complete NMR spectral data of the known 4,5-di-p-trans-coumaroylquinic acid (4). The antioxidant activity represented as DPPH free radical scavenging activity was investigated revealing that the di-p-coumaroylquinic acid derivatives possess potent antioxidant activity so considered the major constituents contributing to the antioxidant effect of the plant. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Aspergillus fumigatus CY018, an endophytic fungus in Cynodon dactylon as a versatile producer of new and bioactive metabolites.

    PubMed

    Liu, J Y; Song, Y C; Zhang, Z; Wang, L; Guo, Z J; Zou, W X; Tan, R X

    2004-11-09

    Aspergillus fumigatus CY018 was recognized as an endophytic fungus for the first time in the leaf of Cynodon dactylon. By bioassay-guided fractionation, the EtOAc extract of a solid-matrix steady culture of this fungus afforded two new metabolites, named asperfumoid (1) and asperfumin (2), together with six known bioactive compounds including monomethylsulochrin, fumigaclavine C, fumitremorgin C, physcion, helvolic acid and 5alpha,8alpha-epidioxy-ergosta-6,22-diene-3beta-ol as well as other four known compounds ergosta-4,22-diene-3beta-ol, ergosterol, cyclo(Ala-Leu) and cyclo(Ala-Ile). Through detailed spectroscopic analyses including HRESI-MS, homo- and hetero-nuclear correlation NMR experiments (HMQC, COSY, NOESY and HMBC), the structures of asperfumoid and asperfumin were established to be spiro-(3-hydroxyl-2,6-dimethoxyl-2,5-diene-4-cyclohexone-(1,3')-5'-methoxyl-7'-methyl-(1'H, 2'H, 4'H)-quinoline-2',4'-dione) and 5-hydroxyl-2-(6-hydroxyl-2-methoxyl-4-methylbenzoyl)-3,6-dimethoxyl-benzoic methyl ester, respectively. All of the 12 isolates were subjected to in vitro bioactive assays against three human pathogenic fungi Candida albicans, Tricophyton rubrum and Aspergillus niger. As a result, asperfumoid, fumigaclavine C, fumitremorgin C, physcion and helvolic acid were shown to inhibit C. albicans with MICs of 75.0, 31.5, 62.5, 125.0 and 31.5 microg/mL, respectively.

  16. Databases of Conformations and NMR Structures of Glycan Determinants.

    PubMed

    Sarkar, Anita; Drouillard, Sophie; Rivet, Alain; Perez, Serge

    2015-12-01

    The present study reports a comprehensive nuclear magnetic resonance (NMR) characterization and a systematic conformational sampling of the conformational preferences of 170 glycan moieties of glycosphingolipids as produced in large-scale quantities by bacterial fermentation. These glycans span across a variety of families including the blood group antigens (A, B and O), core structures (Types 1, 2 and 4), fucosylated oligosaccharides (core and lacto-series), sialylated oligosaccharides (Types 1 and 2), Lewis antigens, GPI-anchors and globosides. A complementary set of about 100 glycan determinants occurring in glycoproteins and glycosaminoglycans has also been structurally characterized using molecular mechanics-based computation. The experimental and computational data generated are organized in two relational databases that can be queried by the user through a user-friendly search engine. The NMR ((1)H and (13)C, COSY, TOCSY, HMQC, HMBC correlation) spectra and 3D structures are available for visualization and download in commonly used structure formats. Emphasis has been given to the use of a common nomenclature for the structural encoding of the carbohydrates and each glycan molecule is described by four different types of representations in order to cope with the different usages in chemistry and biology. These web-based databases were developed with non-proprietary software and are open access for the scientific community available at http://glyco3d.cermav.cnrs.fr. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Potential of Pseudoshikonin I Isolated from Lithospermi Radix as Inhibitors of MMPs in IL-1β-Induced SW1353 Cells

    PubMed Central

    Lee, Dae Young; Choi, Soo-Im; Han, Se Hee; Lee, Ye-Joo; Choi, Jong-Gil; Lee, Young-Seob; Choi, Je Hun; Lee, Seung-Eun; Kim, Geum-Soog

    2016-01-01

    Pseudoshikonin I, the new bioactive constituent of Lithospermi radix, was isolated from this methanol extract by employing reverse-phase medium-pressure liquid chromatography (MPLC) using acetonitrile/water solvent system as eluents. The chemical structure was determined based on spectroscopic techniques, including 1D NMR (1H, 13C, DEPT), 2D NMR (gCOSY, gHMBC, gHMQC), and QTOF/MS data. In this study, we demonstrated the effect of pseudoshikonin I on matrix-metalloproteinase (MMPs) activation and expression in interleukin (IL)-1β-induced SW1353 chondrosarcoma cells. MMPs are considered important for the maintenance of the extracellular matrix. Following treatment with PS, active MMP-1, -2, -3, -9, -13 and TIMP-2 were quantified in the SW1353 cell culture supernatants using a commercially available ELISA kit. The mRNA expression of MMPs in SW1353 cells was measured by RT-PCR. Pseudoshikonin I treatment effectively protected the activation on all tested MMPs in a dose-dependent manner. TIMP-2 mRNA expression was significantly upregulated by pseudoshikonin I treatment. Overall, we elucidated the inhibitory effect of pseudoshikonin on MMPs, and we suggest its use as a potential novel anti-osteoarthritis agent. PMID:27548143

  18. Potential of Pseudoshikonin I Isolated from Lithospermi Radix as Inhibitors of MMPs in IL-1β-Induced SW1353 Cells.

    PubMed

    Lee, Dae Young; Choi, Soo-Im; Han, Se Hee; Lee, Ye-Joo; Choi, Jong-Gil; Lee, Young-Seob; Choi, Je Hun; Lee, Seung-Eun; Kim, Geum-Soog

    2016-08-18

    Pseudoshikonin I, the new bioactive constituent of Lithospermi radix, was isolated from this methanol extract by employing reverse-phase medium-pressure liquid chromatography (MPLC) using acetonitrile/water solvent system as eluents. The chemical structure was determined based on spectroscopic techniques, including 1D NMR (¹H, (13)C, DEPT), 2D NMR (gCOSY, gHMBC, gHMQC), and QTOF/MS data. In this study, we demonstrated the effect of pseudoshikonin I on matrix-metalloproteinase (MMPs) activation and expression in interleukin (IL)-1β-induced SW1353 chondrosarcoma cells. MMPs are considered important for the maintenance of the extracellular matrix. Following treatment with PS, active MMP-1, -2, -3, -9, -13 and TIMP-2 were quantified in the SW1353 cell culture supernatants using a commercially available ELISA kit. The mRNA expression of MMPs in SW1353 cells was measured by RT-PCR. Pseudoshikonin I treatment effectively protected the activation on all tested MMPs in a dose-dependent manner. TIMP-2 mRNA expression was significantly upregulated by pseudoshikonin I treatment. Overall, we elucidated the inhibitory effect of pseudoshikonin on MMPs, and we suggest its use as a potential novel anti-osteoarthritis agent.

  19. Anti-inflammatory and enzyme inhibitory activities of a crude extract and a pterocarpan isolated from the aerial parts of Vitex agnus-castus.

    PubMed

    Ahmad, Bashir; Azam, Sadiq; Bashir, Shumaila; Khan, Ibrar; Adhikari, Achyut; Choudhary, Muhammad Iqbal

    2010-11-01

    A new compound, 6a,11a-dihydro-6H-[1] benzofuro [3,2-c][1,3]dioxolo[4,5-g]chromen-9-ol was isolated from the ethyl acetate fraction of Vitex agnus-castus. The structure of this compound was identified with the help of spectroscopic techniques ((13)C NMR, (1)H NMR, HMBC, HMQC, NOESY and COSY). The compound showed low urease- (32.0%) and chymotrypsin- (31.4%) inhibitory activity, and moderate (41.3%) anti-inflammatory activity. The crude extract and various fractions obtained from the aerial parts of the plant were also screened for possible in vitro hemagglutination, antibacterial and phytotoxic activities. No hemagglutination activity against human erythrocytes was observed in crude extracts and fractions of V. agnus-castus. The fractions and crude methanolic extract showed moderate and low antibacterial activity. Exceptions were the CHCl(3) fraction, which showed significant antibacterial activity against Klebsiella pneumonia (81% with MIC(50)=2.19 mg/mL), the n-hexane fraction, which exhibited no activity against Salmonella typhi, and the CHCl(3) and aqueous fractions, which showed no activity against Bacillus pumalis. Moderate phytotoxic activity (62.5%) was observed by n-hexane fraction of V. agnus-castus against Lemna minor L at 1000 μg/mL.

  20. Glucosamine and Glucosamine-6-phosphate Derivatives: Catalytic Cofactor Analogs for the glmS Ribozyme

    PubMed Central

    Posakony, Jeffrey J.; Ferré-D'Amaré, Adrian R.

    2013-01-01

    Two analogues of glucosamine-6-phosphate (GlcN6P, 1) and five of glucosamine (GlcN, 2) were prepared for evaluation as catalytic cofactor of the glmS ribozyme, a bacterial gene-regulatory RNA that controls cell wall biosynthesis. Glucosamine and allosamine with 3-azido substitutions were prepared by SN2 reactions of the respective 1,2,4,6-protected sugars; final acidic hydrolysis afforded the fully deprotected compounds as their TFA salts. A 6-phospho-2-aminoglucolactam (31) was prepared from glucosamine in a 13-step synthesis, which included a late-stage POCl3-phosphorylation. A simple and widely applicable 2-step procedure with the triethylsilyl (TES) protecting group was developed to selectively expose the 6-OH group in N-protected glucosamine analogs, which provided another route to chemical phosphorylation. Mitsunobu chemistry afforded 6-cyano (35) and 6-azido (36) analogues of GlcN-(Cbz) and the selectivity for the 6-position was confirmed by NMR (COSY, HMBC, HMQC) experiments. Compound 36 was converted to the fully deprotected 6-azido-GlcN (37) and 2,6-diaminoglucose (38) analogs. A 2-hydroxylamino glucose (42) analogue was prepared via an oxaziridine (41). Enzymatic phosphorylation of 42 and chemical phosphorylation of its 6-OH precursor (43) were possible, but 42 and the 6-phospho product (44) were unstable under neutral or basic conditions. Chemical phosphorylation of the previously described 2-guanidinyl-glucose (46) afforded its 6-phospho analogue (49) after final deprotection. PMID:23578404

  1. Polyketide-Terpene Hybrid Metabolites from an Endolichenic Fungus Pestalotiopsis sp.

    PubMed Central

    Ding, Gang; Wang, Hai-Ying; Guo, Yu-Hua; Shang, Hai

    2017-01-01

    Five new polyketide-terpene hybrid metabolites (1–5) with highly functionalized groups, together with six known derivatives (6–11), were isolated from the endolichenic fungus Pestalotiopsis sp. Their structures were elucidated by extensive NMR experiments including 1H, 13C, HMQC, COSY, and HMBC. The relative configurations of the new compounds were determined by analysis of coupling constants and ROESY correlations. The absolute configurations especially the secondary alcohol at C-15 in 1 and secondary alcohol at C-14 in 5 were established via the CD experiments of the in situ formed [Rh2(OCOCF3)4] complex with the acetonide derivatives. These compounds were tested for their inhibition activity against six plant pathogens. Compounds 1 and 5 exhibited pronounced efficiency against Fusarium oxysporum, and compounds 5 and 6 potently inhibited Fusarium gramineum with MIC value of 8 µg/mL, which revealed the plausible ecological role of endolichenic fungus in providing chemical protection for its host lichen in the fungus-plant relationship. The biosynthetic pathway of compounds 1–11 was postulated for the first time, which paved the way for its further biosynthesis research. PMID:28593175

  2. Polyketide-Terpene Hybrid Metabolites from an Endolichenic Fungus Pestalotiopsis sp.

    PubMed

    Yuan, Chao; Ding, Gang; Wang, Hai-Ying; Guo, Yu-Hua; Shang, Hai; Ma, Xiao-Jun; Zou, Zhong-Mei

    2017-01-01

    Five new polyketide-terpene hybrid metabolites ( 1 - 5 ) with highly functionalized groups, together with six known derivatives ( 6 - 11 ), were isolated from the endolichenic fungus Pestalotiopsis sp. Their structures were elucidated by extensive NMR experiments including 1 H, 13 C, HMQC, COSY, and HMBC. The relative configurations of the new compounds were determined by analysis of coupling constants and ROESY correlations. The absolute configurations especially the secondary alcohol at C-15 in 1 and secondary alcohol at C-14 in 5 were established via the CD experiments of the in situ formed [Rh 2 (OCOCF 3 ) 4 ] complex with the acetonide derivatives. These compounds were tested for their inhibition activity against six plant pathogens. Compounds 1 and 5 exhibited pronounced efficiency against Fusarium oxysporum , and compounds 5 and 6 potently inhibited Fusarium gramineum with MIC value of 8  µ g/mL, which revealed the plausible ecological role of endolichenic fungus in providing chemical protection for its host lichen in the fungus-plant relationship. The biosynthetic pathway of compounds 1 - 11 was postulated for the first time, which paved the way for its further biosynthesis research.

  3. Preparation and structural characterization of poly-mannose synthesized by phosphoric acid catalyzation under microwave irradiation.

    PubMed

    Wang, Haisong; Cheng, Xiangrong; Shi, Yonghui; Le, Guowei

    2015-05-05

    Poly-mannose with molecular weight of 2.457 kDa was synthesized using d-mannose as substrate and phosphoric acid as catalyst under the condition of microwave irradiation for the first time. The optimum reaction conditions were microwave output power of 900 W, temperature 115°C, proton concentration 2.5 mol/L, and microwave irradiation time 5 min. The actual maximum yield was 91.46%. After purified by Sepherdex G-25 column chromatography, the structural features of poly-mannose were investigated by high-performance anion-exchange chromatography (HPAEC), high-performance gel-permeation chromatography (HPGPC), infrared (IR) spectroscopy, methylation analysis and NMR spectroscopy analysis ((1)H, (13)C, COSY, TOCSY, HMQC, and HMBC). HPAEC analysis showed that the composition of synthetic polysaccharides was d-mannose, its purity was demonstrated by HPGPC as a single symmetrical sharp peak, and additionally IR spectra demonstrated the polymerization of d-mannose. Methylation analysis and NMR spectroscopy revealed that the backbone of poly-mannose consisting of (1→3)-linked β-d-Manp, (1→3)-linked α-d-Manp, and (1→6)-linked α-d-Manp residues, and the main chain were branched at the O-2, O-3, O-4, O-6 position. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. New constituents from noni (Morinda citrifolia) fruit juice.

    PubMed

    Samoylenko, Volodymyr; Zhao, Jianping; Dunbar, D Chuck; Khan, Ikhlas A; Rushing, James W; Muhammad, Ilias

    2006-08-23

    Morinda citrifolia L. (Rubiaceae), known as noni, has a long history of traditional use in the Hawaiian and Tahitian islands. More recently, an array of commercial noni fruit juice products are gaining popularity as dietary supplements, with claims of anticancer and immunostimulant activities. The biologically active principles of noni are not fully known. In continuation of work on the isolation of markers from dietary supplements, this paper reports the isolation of three new markers, namely, 1-O-(3'-methylbut-3'-enyl)-beta-D-glucopyranose (1), 1-n-butyl-4-(5'-formyl-2'-furanyl)methyl succinate (2), and 4-epi-borreriagenin (3), together with the known iridoid glycosides asperulosidic acid (4) and deacetylasperulosidic acid (5) and a mixture of 1-n-butyl-4-methyl-2-hydroxysuccinate (6a) and 1-n-butyl-4-methyl-3-hydroxysuccinate (6b), as well as a mixture of alpha- and beta-glucopyranose from noni fruit juice obtained from Puerto Rico. The structures of compounds were based on 1H and 13C NMR, mainly 2D NMR COSY, HMQC, HMBC, and NOESY experiments, and HRMS. Furthermore, samples from fresh-squeezed noni fruit juice from Japan revealed the presence of scopoletin (7), in addition to compounds 1-6, indicating no significant differences in the marker constituents of noni collected from Atlantic and Pacific regions.

  5. Conformation of repaglinide: A solvent dependent structure

    NASA Astrophysics Data System (ADS)

    Chashmniam, Saeed; Tafazzoli, Mohsen

    2017-09-01

    Experimental and theoretical conformational study of repaglinide in chloroform and dimethyl sulfoxide was investigated. By applying potential energy scanning (PES) at B3LYP/6-311++g** and B3LYP-D3/6-311++g** level of theory on rotatable single bonds, four stable conformers (R1-R4) were identified. Spin-spin coupling constant values were obtained from a set of 2D NMR spectra (Hsbnd H COSY, Hsbnd C HMQC and Hsbnd C HMBC) and compared to its calculated values. Interestingly, from 1HNMR and 2D-NOESY NMR, it has been found that repaglinide structure is folded in CDCl3 and cause all single bonds to rotate at an extremely slow rate. On the other hand, in DMSO-d6, with strong solvent-solute intermolecular interactions, the single bonds rotate freely. Also, energy barrier and thermodynamic parameters for chair to chair interconversion was measured (13.04 kcal mol-1) in CDCl3 solvent by using temperature dynamic NMR.

  6. Sesquiterpene Lactones from Cynara cornigera: Acetyl Cholinesterase Inhibition and In Silico Ligand Docking.

    PubMed

    Hegazy, Mohamed-Elamir F; Ibrahim, Abeer Y; Mohamed, Tarik A; Shahat, Abdelaaty A; El Halawany, Ali M; Abdel-Azim, Nahla S; Alsaid, Mansour S; Paré, Paul W

    2016-01-01

    Wild artichoke (Cynara cornigera), a thistle-like perennial belonging to the Asteraceae family, is native to the Mediterranean region, northwestern Africa, and the Canary Islands. While the pleasant, albeit bitter, taste of the leaves and flowers is attributed to the sesquiterpene lactones cynaropicrin and cynarin, a comprehensive phytochemical investigation still needs to be reported. In this study seven sesquiterpene lactones were isolated from an aqueous methanol plant extract, including a new halogenated metabolite (1), the naturally isolated compound sibthorpine (2), and five metabolites isolated for the first time from C. cornigera. Structures were established by spectroscopic methods, including HREIMS, (1 )H, (13 )C, DEPT, (1 )H-(1 )H COSY, HMQC, and HMBC-NMR experiments as well as by X-ray analysis. The isolated bioactive nutrients were analyzed for their antioxidant and metal chelating activity. Compound 1 exhibited a potent metal chelating activity as well as a high antioxidant capacity. Moreover, select compounds were effective as acetyl cholinesterase inhibitors presenting the possibility for such compounds to be examined for anti-neurodegenerative activity. A computational pharmacophore elucidation and docking study was performed to estimate the pharmacophoric features and binding conformation of isolated compounds in the acetyl cholinesterase active site. Georg Thieme Verlag KG Stuttgart · New York.

  7. Antioxidant and Anti-Osteoporotic Activities of Aromatic Compounds and Sterols from Hericium erinaceum.

    PubMed

    Li, Wei; Lee, Sang Hyun; Jang, Hae Dong; Ma, Jin Yeul; Kim, Young Ho

    2017-01-11

    Hericium erinaceum , commonly called lion's mane mushroom, is a traditional edible mushroom widely used in culinary applications and herbal medicines in East Asian countries. In this study, a new sterol, cerevisterol 6-cinnamate ( 6 ), was isolated from the fruiting bodies of H. erinaceum together with five aromatic compounds 1 - 5 and five sterols 7 - 11 . The chemical structures of these compounds were elucidated using chemical and physical methods and comparison of HRESIMS, ¹D-NMR (¹H, 13 C, and DEPT) and 2D-NMR (COSY, HMQC, HMBC, and NOESY) spectra with previously reported data. The antioxidant and anti-osteoporotic activities of extracts and the isolated compounds 1 - 11 were investigated. All compounds exhibited peroxyl radical-scavenging capacity but only compounds 1 , 3 , and 4 showed potent reducing capacity. Moreover, compounds 1 , 2 , 4 , and 5 showed moderate effects on cellular antioxidant activity and inhibited the receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastic differentiation. These results suggested that H. erinaceum could be utilized in the development of natural antioxidant and anti-osteoporotic nutraceuticals and functional foods.

  8. Band-selective excited ultrahigh resolution PSYCHE-TOCSY: fast screening of organic molecules and complex mixtures.

    PubMed

    Kakita, Veera Mohana Rao; Vemulapalli, Sahithya Phani Babu; Bharatam, Jagadeesh

    2016-04-01

    Precise assignments of (1) H atomic sites and establishment of their through-bond COSY or TOCSY connectivity are crucial for molecular structural characterization by using (1) H NMR spectroscopy. However, this exercise is often hampered by signal overlap, primarily because of (1) H-(1) H scalar coupling multiplets, even at typical high magnetic fields. The recent developments in homodecoupling strategies for effectively suppressing the coupling multiplets into nice singlets (pure-shift), particularly, Morris's advanced broadband pure-shift yielded by chirp excitation (PSYCHE) decoupling and ultrahigh resolution PSYCHE-TOCSY schemes, have shown new possibilities for unambiguous structural elucidation of complex organic molecules. The superior broadband PSYCHE-TOCSY exhibits enhanced performance over the earlier TOCSY methods, which however warrants prolonged experimental times due to the requirement of large number of dwell increments along the indirect dimension. Herein, we present fast and band-selective analog of the broadband PSYCHE-TOCSY, which is useful for analyzing complex organic molecules that exhibit characteristic yet crowded spectral regions. The simple pulse scheme relies on band-selective excitation (BSE) followed by PSYCHE homodecoupling in the indirect dimension. The BSE-PSYCHE-TOCSY has been exemplified for Estradiol and a complex carbohydrate mixture comprised of six constituents of closely comparable molecular weights. The experimental times are greatly reduced viz., ~20 fold for Estradiol and ~10 fold for carbohydrate mixture, with respect to the broadband PSYCHE-TOCSY. Furthermore, unlike the earlier homonuclear band-selective decoupling, the BSE-PSYCHE-decoupling provides fully decoupled pure-shift spectra for all the individual chemical sites within the excited band. The BSE-PSYCHE-TOCSY is expected to have significant potential for quick screening of complex organic molecules and mixtures at ultrahigh resolution. Copyright © 2015 John Wiley

  9. Dual-component system dimethyl sulfoxide/LiCl as a solvent and catalyst for homogeneous ring-opening grafted polymerization of ε-caprolactone onto xylan.

    PubMed

    Zhang, Xue-Qin; Chen, Ming-Jie; Liu, Chuan-Fu; Sun, Run-Cang

    2014-01-22

    The preparation of xylan-graft-poly(ε-caprolactone) (xylan-g-PCL) copolymers was investigated by homogeneous ring-opening polymerization (ROP) in a dual-component system containing Lewis base LiCl and strong polar aprotic solvent dimethyl sulfoxide (DMSO). DMSO/LiCl acted as solvent, base, and catalyst for the ROP reaction. The effects of the parameters, including the reaction temperature, molar ratio of ε-caprolactone (ε-CL) to anhydroxylose units (AXU) in xylan, and reaction time, on the degree of substitution (DS) and weight percent of PCL side chain (WPCL) were investigated. The results showed that xylan-g-PCL copolymers with low DS in the range of 0.03-0.39 were obtained under the given conditions. The Fourier transform infrared spectroscopy (FTIR), (1)H nuclear magnetic resonance (NMR), (13)C NMR, (1)H-(1)H correlation spectroscopy (COSY), and (1)H-(13)C correlation two-dimensional (2D) NMR [heteronuclear single-quantum coherence (HSQC)] characterization provided more evidence of the attachment of side chains onto xylan. Only one ε-CL was confirmed to be attached onto xylan with each side chain. Integration of resonances assigned to the substituted C2 and C3 in the HSQC spectrum also indicated 69.23 and 30.77% of PCL side chains attached to AXU at C3 and C2 positions, respectively. Although the attachment of PCL onto xylan led to the decreased thermal stability of xylan, the loss of unrecovered xylan fractions with low molecular weight because of the high solubility of xylan in DMSO/LiCl resulted in the increased thermal stability of the samples. This kind of xylan derivative has potential application in environmentally friendly and biodegradable materials considering the good biodegradability of xylan and PCL.

  10. Two novel bioactive glucosinolates from Broccoli (Brassica oleracea L. var. italica) florets.

    PubMed

    Survay, Nazneen Shaik; Kumar, Brajesh; Jang, Mi; Yoon, Do-Young; Jung, Yi-Sook; Yang, Deok-Chun; Park, Se Won

    2012-09-01

    Two novel glucosinolates along with one known glucosinolate were isolated from Broccoli (Brassica oleracea L. var. italica) florets. Their structures were established mainly by 1D ((1)H and (13)C NMR), 2D NMR ((1)H-(1)H COSY, DEPT 135°, HSQC and HMBC), and Tandem MS-MS spectrometric data as 2-mercaptomethyl sulfinyl glucosinolate [(Z)-4-(methylsulfinyl)-N-(sulfooxy)-2-((2'S,3'R,4'S,5'S,6'R)-3',4',5'-trihydroxy-6'(hydroxylmethyl)-2'-mercapto tetrahydro-2H-pyran-2-yl) butane amide] 1, (Z)-1-((2S,5S)-5-hydroxytetra-hydro-2H-pyran-2-ylthio)-2-(1H-indol-3-yl) ethylidene amino sulfate 2 and a known cinnamoyl [6'-O-trans-(4″-hydroxy cinnamoyl)4-(methylsulphinyl)butyl glucosinolate] 3. Compound 1 exhibited scavenging activity against DPPH with an inhibitory concentration IC(50) of 20 mM, whereas compound 3 was a weak antioxidant when compared to the standard quercetin (5 mM) as a positive control. Both the compounds showed a significant and similar antimicrobial activity against Staphylococcus aureus with an IC(50) of <625 μg/mL when compared to antibiotic duricef. Against Salmonella typhimurium the IC(50) of 1 and 3 was determined as <625 μg/mL and <1250 μg/mL, respectively, when compared to ampicillin (IC(50) ≤ 39 μg/mL) as a positive control. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. NMR Metabolic profiling of green tea (Camellia sinensis L.) leaves grown at Kemuning, Indonesia

    NASA Astrophysics Data System (ADS)

    Wahyuni, D. S. C.; Kristanti, M. W.; Putri, R. K.; Rinanto, Y.

    2017-01-01

    Green tea (Camellia sinensis L.) has been famous as a beverage and natural medicine. It contains a broad range of primary and secondary metabolites i.e. polyphenols. Nuclear Magnetic Resonance (NMR) has been widely used for metabolic profiling in medicinal plants. It provides a very fast and detailed analysis of the biomolecular composition of crude extracts. Moreover, an NMR spectrum is a physical characteristic of a compound and thus highly reproducible. Therefore, this study aims to profile metabolites of three different varieties of green tea C. Sinensis grown in Kemuning, Middle Java. Three varieties of green tea collected on Kemuning (TR1 2025, Gambung 4/5, and Chiaruan 143) were used in this study. 1H-NMR spectra were recorded at 230C on a 400 MHz Agilent WB (Widebore). The analysis was performed on dried green tea leaves and analyzed by 1H-NMR, 2D-J-resolved and 1H-1H correlated spectroscopy (COSY). MestRenova version 11.0.0 applied to identify metabolites in samples. A 1H-NMR spectrum of tea showed amino acids and organic acids signal at the area δ 0.8-4.0. These were theanine, alanine, threonine, succinic acid, aspartic acid, lactic acid. Anomeric protons of carbohydrate were shown by the region of β-glucose, α-glucose, fructose and sucrose. The phenolic region was depicted at area δ 5.5-8.5. Epigallocatechin derivates and caffeine were detected in the tea leaves. The detail compound identification was observed and discussed in the text.

  12. Structural characterization of constituents with molecular diversity in fractions from Lysidice brevicalyx by liquid chromatography/diode-array detection/electrospray ionization tandem mass spectrometry and liquid chromatography/nuclear magnetic resonance.

    PubMed

    Qu, Jing; Hu, You-cai; Li, Jian-bei; Wang, Ying-hong; Zhang, Jin-lan; Abliz, Zeper; Yu, Shi-shan; Liu, Yun-bao

    2008-01-01

    A combination of electrospray ionization tandem mass spectrometry with high-performance liquid chromatography (HPLC/ESI-MSn), and hyphenation of liquid chromatography to nuclear magnetic resonance spectroscopy (HPLC/NMR), have been extensively utilized for on-line analysis of natural products, analyzing metabolite and drug impurity. In our last paper, we reported an on-line analytical method for structural identification of trace alkaloids in the same class. However, the structural types of the constituents in plants were various, such as flavanoids, terpenoids and steroids. It is important to establish an effective analytical method for on-line structural identification of constituents with molecular diversity in extracts of plants. So, in the present study, the fragmentation patterns of some isolated stilbenes, phloroglucinols and flavanoids from Lysidice rhodostegia were investigated by ESI-MSn. Their fragmentation rules and UV characteristics are summarized, and the relationship between the spectral characteristics, rules and the structures is described. According to the fragmentation rules, NMR and UV spectral characteristics, 24 constituents of different types in the fractions from L. brevicalyx of the same genus were structurally characterized on the basis of HPLC/HRMS, HPLC-UV/ESI-MSn, HPLC/1H NMR and HPLC/1H-1H COSY rapidly. Of these, six (10, 13, 14, 16, 17 and 23) are new compounds and all of them are reported from L. brevicalyx for the first time. The aim is to develop an effective analytical method for on-line structural identification of natural products with molecular diversity in plants, and to guide the rapid and direct isolation of novel compounds by chemical screening.

  13. The new Schiff base 4-[(4-Hydroxy-3-fluoro-5-methoxy-benzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one: Experimental, DFT calculational studies and in vitro antimicrobial activity

    NASA Astrophysics Data System (ADS)

    İskeleli, Nazan Ocak; Alpaslan, Yelda Bingöl; Direkel, Şahin; Ertürk, Aliye Gediz; Süleymanoğlu, Nevin; Ustabaş, Reşat

    2015-03-01

    The synthesized Schiff base, 4-[(4-Hydroxy-3-fluoro-5-methoxy-benzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one (I), has been characterized by 13C NMR, 1H NMR, 2D NMR (1H-1H COSY and 13C APT), FT-IR, UV-vis and X-ray single-crystal techniques. Molecular geometry of the compound I in the ground state, vibrational frequencies and chemical shift values have been calculated by using the density functional method (DFT) with 6-311++G(d,p) basis set. The obtained results indicate that optimized geometry can well reflect the crystal structural parameters. The differences between experimental and calculated results of FT-IR and NMR have supported the existence of intermolecular (O-H⋯O type) and intramolecular (C-H⋯O type) hydrogen bonds in the crystal structure. Molecular electrostatic potential (MEP), frontier molecular orbital analysis (HOMO-LUMO) and electronic absorption spectra were carried out at B3LYP/6-311G++(d,p). HOMO-LUMO electronic transition of 3.92 eV is due to contribution of the bands the n → π∗. The antimicrobial activity of the compound I was determined against the selected 11 bacteria and 8 fungi by microdilution broth assay with Alamar Blue. In vitro studies showed that the compound I has no antifungal effect for selected fungal isolates. However, the compound I shows remarkable antibacterial effect for the bacteria; Streptococcus pneumoniae, Haemophilus influenzae and Enterococcus faecalis.

  14. The Effect of Terminal Substitution on the Helical Carbon Structure of Fluoro-Alkane Chains: a Pure Rotational Study of CH2OH-Cn-1F2n-1 (n = 4, 5,& 6)

    NASA Astrophysics Data System (ADS)

    Schwartz, Aaron Z. A.; Maturo, Mark P.; Obenchain, Daniel A.; Cooke, S. A.

    2016-06-01

    Continuing a series of studies to investigate the change in structure of hydrocarbons as the amount of fluorination is increased to varying degrees of substitution, we present a survey on the change in the helical nature of the fluorinated carbon backbone when a -CH2OH group is substituted for a terminal - CF3 group. Spectra for 1H,1H-heptafluorobutan-1-ol, 1H,1H-nonafluoropentan-1-ol, and 1H,1H-undecafluorohexan-1-ol were collected separately using a chirped-pulse FTMW spectrometer in the range of 7-13 GHz. Only one conformation was observed for each molecule. Additional measurements of the 1H,1H-heptafluorobutan-1-ol were completed using a Balle-Flygare cavity instrument. Assignments of the singly-substituted 13C isotopologues of the 1H,1H-heptafluorobutan-1-ol were also measured. A comparison of both ab initio and experimental structures will be presented.

  15. New triterpenoid saponins from Leontice smirnowii.

    PubMed

    Tabatadze, Nino; Bun, Sok-Siya; Tabidze, Badri; Mshvildadze, Vakhtang; Dekanosidze, Genri; Ollivier, Evelyne; Elias, Riad

    2010-10-01

    Three new triterpene saponins, leonticins I (1), J (2) and L (3) were isolated from the tubers of Leontice smirnowii. On the basis of spectroscopic methods, including 2D NMR experiments (DEPT, gs-COSY, gs-HMQC, gs-HMBC and gs-HSQC-TOCSY), mass spectrometry (HR-ESI-MS) and chemical degradation, the structures of the new compounds were elucidated as 3-O-β-D-glucopyranosyl-(1 → 3)-[β-D-xylopyranosyl-1 → 2)]-α-L-arabinopyranosyl-28-O-[α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl]-3β-hydroxy-30-norolean-12,20(29)-dien-28-oic acid (1), 3-O-[β-D-xylopyranosyl-(1 → 3)-β-D-galactopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 3)-α-L-arabinopyranosyl]-28-O-[α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl]-3β-hydroxy-30-norolean-12,20(29)-dien-28-oic acid (2) and 3-O-[β-D-xylopyranosyl-(1 → 3)-β-D-galactopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 3)]-[β-D-xylopyranosyl-(1 → 2)]-α-L-arabinopyranosyl]-28-O-[α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl]-3β-hydroxy-30-norolean-12,20(29)-dien-28-oic acid (3), respectively. The aglycone 3β-hydroxy-30-norolean-12,20(29)-dien-28-oic acid was observed for the first time in Leontice species. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. NMR investigation and theoretical calculations of the solvent effect on the conformation of valsartan

    NASA Astrophysics Data System (ADS)

    Chashmniam, Saeed; Tafazzoli, Mohsen

    2017-11-01

    Structure and conformational properties of valsartan were studied by advanced NMR techniques and quantum calculation methods. Potential energy scanning using B3LYP/6-311++g** and B3LYP-D3/6-311++g** methods were performed and four conformers (V1-V4) at minimum points of PES diagram were observed. According to the NMR spectra in acetone-d6, there are two conformers (M and m) with m/M = 0.52 ratio simultaneously and energy barriers of the two conformers were predicted from chemical shifts and multiplicities. While, intramolecular hydrogen bond at tetrazole ring and carboxylic groups prevent the free rotation on N6sbnd C11 bond in M-conformer, this bond rotates freely in m-conformer. On the other hand, intramolecular hydrogen bond at carbonyl and carboxylic acid can be observed at m-conformer. So, different intramolecular hydrogen bond is the reason for the stability of both M and m structures. Quite interestingly, 1H NMR spectra in CDCl3 show two distinct conformers (N and n) with unequal ratio which are differ from M-m conformers. Also, intramolecular hydrogen bond seven-member ring involving five-membered tetrazole ring and carboxylic acid group observed in both N and n-conformers Solvent effect, by using a set of polar and non-polar solvents including DMSO-d6, methanol-d4, benzene-d6, THF-d8, nitromethane-d3, methylene chloride-d2 and acetonitrile-d3 were investigated. NMR parameters include chemical shifts and spin-spin coupling constants were obtained from a set of 2D NMR spectra (H-H COSY, HMQC and HMBC). For this purpose, several DFT functionals from LDA, GGA and hybrid categories were used which the hybrid method showed better agreement with experiment values.

  17. New anti-trypanosomal active tetracyclic iridoid isolated from Morinda lucida Benth.

    PubMed

    Suzuki, Mitsuko; Tung, Nguyen Huu; Kwofie, Kofi D; Adegle, Richard; Amoa-Bosompem, Michael; Sakyiamah, Maxwell; Ayertey, Frederick; Owusu, Kofi Baffour-Awuah; Tuffour, Isaac; Atchoglo, Philip; Frempong, Kwadwo Kyereme; Anyan, William K; Uto, Takuhiro; Morinaga, Osamu; Yamashita, Taizo; Aboagye, Frederic; Appiah, Alfred Ampomah; Appiah-Opong, Regina; Nyarko, Alexander K; Yamaoka, Shoji; Yamaguchi, Yasuchika; Edoh, Dominic; Koram, Kwadwo; Ohta, Nobuo; Boakye, Daniel A; Ayi, Irene; Shoyama, Yukihiro

    2015-08-01

    Human African trypanosomiasis (HAT), commonly known as sleeping sickness has remained a serious health problem in many African countries with thousands of new infected cases annually. Chemotherapy, which is the main form of control against HAT has been characterized lately by the viewpoints of toxicity and drug resistance issues. Recently, there have been a lot of emphases on the use of medicinal plants world-wide. Morinda lucida Benth. is one of the most popular medicinal plants widely distributed in Africa and several groups have reported on its anti-protozoa activities. In this study, we have isolated one novel tetracyclic iridoid, named as molucidin, from the CHCl3 fraction of the M. lucida leaves by bioassay-guided fractionation and purification. Molucidin was structurally elucidated by (1)H and (13)C NMR including HMQC, HMBC, H-H COSY and NOESY resulting in tetracyclic iridoid skeleton, and its absolute configuration was determined. We have further demonstrated that molucidin presented a strong anti-trypanosomal activity, indicating an IC50 value of 1.27 μM. The cytotoxicity study using human normal and cancer cell lines indicated that molucidin exhibited selectivity index (SI) against two normal fibroblasts greater than 4.73. Furthermore, structure-activity relationship (SAR) study was undertaken with molucidin and oregonin, which is identical to anti-trypanosomal active components of Alnus japonica. Overlapping analysis of the lowest energy conformation of molucidin with oregonin suggested a certain similarities of aromatic rings of both oregonin and molucidin. These results contribute to the future drug design studies for HAT. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. The Antimicrobial Activity of Annona emarginata (Schltdl.) H. Rainer and Most Active Isolated Compounds against Clinically Important Bacteria.

    PubMed

    Dolab, Juan G; Lima, Beatriz; Spaczynska, Ewelina; Kos, Jiri; Cano, Natividad H; Feresin, Gabriela; Tapia, Alejandro; Garibotto, Francisco; Petenatti, Elisa; Olivella, Monica; Musiol, Robert; Jampilek, Josef; Enriz, Ricardo D

    2018-05-16

    Annona emarginata (Schltdl.) H. Rainer, commonly known as "arachichú", "araticú", "aratigú", and "yerba mora", is a plant that grows in Argentina. Infusions and decoctions are used in folk medicine as a gargle against throat pain and for calming toothache; another way to use the plant for these purposes is chewing its leaves. Extracts from bark, flowers, leaves, and fruits from A. emarginata were subjected to antibacterial assays against a panel of Gram (+) and Gram (-) pathogenic bacteria according to Clinical and Laboratory Standards Institute protocols. Extracts from the stem bark and leaves showed moderate activity against the bacteria tested with values between 250⁻1000 µg/mL. Regarding flower extracts, less polar extracts (hexane, dichloromethane) showed very strong antibacterial activity against methicillin-sensitive Staphylococcus aureus ATCC 25923 and methicillin-resistant S. aureus ATCC 43300 with values between 16⁻125 µg/mL. Additionally, hexane extract showed activity against Klebsiella pneumoniae (MIC = 250 µg/mL). The global methanolic extract of the fruits (MeOHGEF) was also active against the three strains mentioned above, with MICs values 250⁻500 µg/mL. Bioassay-guided fractionation of MeOHGEF led to the isolation of a new main compound-( R )-2-(4-methylcyclohex-3-en-1-yl)propan-2-yl ( E )-3-(4-hydroxyphenyl)acrylate ( 1 ). The structure and relative configurations have been determined by means of 1D and 2D NMR techniques, including COSY, HMQC, HMBC, and NOESY correlations. Compound 1 showed strong antimicrobial activity against all Gram (+) species tested (MICs = 3.12⁻6.25 µg/mL). In addition, the synthesis and antibacterial activity of some compounds structurally related to compound 1 (including four new compounds) are reported. A SAR study for these compounds was performed based on the results obtained by using molecular calculations.

  19. Complete structure of the polysaccharide from Streptococcus sanguis J22

    SciTech Connect

    Abeygunawardana, C.; Bush, C.A.; Cisar, J.O.

    1990-01-09

    The cell wall polysaccharides of certain oral streptococci such as Streptococcus sanguis strains 34 and J22, although immunologically distinct, act as receptors for the fimbrial lectins of Actinomyces viscosus T14V. The authors report the complete covalent structure of the polysaccharide from S. sanguis J22 which is composed of a heptasaccharide subunit linked by phosphodiester bonds. The repeating subunit, which contains {alpha}-GalNAc, {alpha}-rhamnose, {beta}-rhamnose, {beta}-glucose, and {beta}-galactose all in the pyranoside form and {beta}-galactofuranose, is compared with the previously published structure of the polysaccharide from strain 34. The structure has been determined almost exclusively by high-resolution nuclear magnetic resonance methods. Themore » {sup 1}H and {sup 13}C NMR spectra of the polysaccharides from both strains 34 and J22 have been completely assigned. The stereochemistry of pyranosides was assigned from J{sub H-H} values determined from phase-sensitive COSY spectra, and acetamido sugars were assigned by correlation of the resonances of the amide {sup 1}H with the sugar ring protons. The {sup 13}C spectra were assigned by {sup 1}H-detected multiple-quantum correlation (HMQC) spectra, and the assignments were confirmed by {sup 1}H-detected multiple-bond correlation (HMBC) spectra. The positions of the glycosidic linkages were assigned by detection of three-bond {sup 1}H-{sup 13}C correlation across the glycosidic linkage in the HMBC spectra. The positions of the phosphodiester linkages were determined by splittings observed in the {sup 13}C resonances due to {sup 31}P coupling and also by {sup 1}H-detected {sup 31}P correlation spectroscopy.« less

  20. Allelochemicals and activities in a replanted Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) tree ecosystem.

    PubMed

    Kong, C H; Chen, L C; Xu, X H; Wang, P; Wang, S L

    2008-12-24

    Autotoxicity is a major reason for replant problems in managed tree ecosystems. Studies have related phenolics-based allelochemicals to autotoxicity. We selected a 20-year-old replanted Chinese fir [Cunninghamia lancealata (Lamb.) Hook] tree ecosystem to isolate, identify, determine the biological activity of, and quantify soil phytotoxins. Eight common phenolics (coumarin, vanillin, isovanillin, and p-hydroxybenzoic, vanillic, benzoic, cinnamic, and ferulic acids), friedelin, and a novel cyclic dipeptide (6-hydroxy-1,3-dimethyl-8-nonadecyl-[1,4]-diazocane-2,5-diketone) were obtained by using the bioassay-guided isolation technique from toxic soil of the replanted Chinese fir tree ecosystem. Chemical structures were determined by spectroscopic means, including 2D-NMR (COSY, HMQC, HMBC, and NOESY) experiments. High concentrations of soil phenolics and friedelin were observed in the natural evergreen broadleaf forest (CK) rather than in the Chinese fir tree ecosystem. The phenolics and friedelin were not phytotoxic to Chinese fir trees. However, the cyclic dipeptide inhibited Chinese fir growth at soil concentrations determined in the replanted Chinese fir tree ecosystem. There was a significantly higher soil concentration of cyclic dipeptide in the replanted Chinese fir tree ecosystem than in a fresh Chinese fir tree ecosystem. The results suggest that phenolics and friedelin are not key allelochemicals since they are weakly phytotoxic and are detected in low concentrations in the replanted Chinese fir tree ecosystem, while cyclic dipeptide is a highly active allelochemical with a phytotoxic effect that limits offspring growth in the replanted Chinese fir tree ecosystem. The discovery of cyclic dipeptide, as well as a further understanding of its potential action mechanism in the replanted Chinese fir tree ecosystem, may contribute to solving the replant problems in managed tree ecosystems.

  1. Activity in vitro and in vivo against Trypanosoma cruzi of a furofuran lignan isolated from Piper jericoense.

    PubMed

    García-Huertas, Paola; Olmo, Francisco; Sánchez-Moreno, Manuel; Dominguez, Jorge; Chahboun, Rachid; Triana-Chávez, Omar

    2018-06-01

    Piperaceae species are abundant in the tropics and are important components of secondary vegetation. Many of these plants have received considerable attention due to their wide range of biological activities. Here, the trypanocidal activity of extracts and fractions with different polarities obtained from Colombian Piper jericoense plant was evaluated. A furofuran lignan, (1S,3aS,4S,6aS)-1-(3',4'-dimethoxyphenyl)-4-(3″,4″-methylendioxyphenyl)hexahydrofuro[3,4-c]furan, (1), was isolated from Colombian Piper jericoense leaves ethyl acetate extract. Its relative configuration at the stereogenic centers was established on the basis of various spectroscopic analyses, including 1D- (1H, 13C, and DEPT) and 2D-NMR (COSY, NOESY, HMQC and HMBC) and a 2D INADEQUATE NMR experiment as well as by comparison of their spectral data with those of related compounds such as (+)-Kobusin (2). The activity against Trypanosoma cruzi indicated that compound 1 was active against all parasite forms (epimastigote, amastigote and trypomastigote) and presented lower toxicity than the reference drug, benznidazole (Bz), evidenced by a selective index of 18.4 compared to that of Bz, which was 6.7. Moreover, this compound inhibited the infectious process, and it was active in infected mice in the acute phase. This compound significantly inhibited the T. cruzi Fe-SOD enzyme, whereas Cu/Zn-SOD from human cells was not affected. Ultrastructural analyses, together with metabolism-excretion studies in the parasite, were also performed to identify the possible mechanism of action of the tested compound. Interestingly, the lignan affected the parasite structure, but it did not alter the energetic metabolism. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. Synthesis and Cytotoxic Activities of Difluoro-Dimethoxy Chalcones.

    PubMed

    Yamali, Cem; Gul, Halise Inci; Ozgun, Dilan Ozmen; Sakagam, Hiroshi; Umemura, Naoki; Kazaz, Cavit; Gul, Mustafa

    2017-01-01

    Although anticancer chemotherapeutics are available in markets, side effects related to the drugs in clinical use lead to researchers to investigate new drug candidates which are more safe, potent and selective than others. Chalcones are popular with their anticancer activities with the several reported mechanisms including inhibition of angiogenesis, inhibition of tubulin polymerization, and induction of apoptosis etc. This study was focused on to synthesize of 1-(2,4/2,6-difluorophenyl)-3-(2,3/2,4/2,5/3,4- dimethoxyphenyl)-2-propen-1-ones (1-8) and investigate their cytotoxic properties with possible mechanism of action. The compounds were synthesized by Claisen-Schmidt condensation. The chemical structures were confirmed by 1H NMR, 13C NMR, DEPT, COSY, HMQC, HMBC, 19F NMR and HRMS. In vitro cytotoxic effects of the compounds against human tumour cell lines [gingival carcinoma (Ca9-22), oral squamous cell carcinoma (HSC-2)] and human normal oral cells [gingival fibroblasts (HGF), periodontal ligament fibroblasts (HPLF)] were evaluated via MTT test. All compounds had higher cytotoxicity than reference compound 5-Fluorouracil (5-FU). The compounds 3-7 had higher potency selectivity expression values (PSE) than 5-FU and PSE values of the compounds were over 100. All chalcone derivatives seem good candidates for further studies according to very remarkable and high PSE values. It was clearly demonstrated that compound 7 can induce early apoptosis at a concentration of 10 µM and dose-dependent late apoptosis starting at 10 µM. Compound 7 induced cleavage of the apoptosis marker PARP. The results indicate that new chalcones reported here can promote apoptosis in human tumour cell lines. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Band selective small flip angle COSY: a simple experiment for the analyses of 1H NMR spectra of small chiral molecules.

    PubMed

    Prabhu, Uday Ramesh; Suryaprakash, N

    2008-12-01

    The NMR spectroscopic discrimination of enantiomers in the chiral liquid crystalline solvent is more often carried out using (2)H detection in its natural abundance. The employment of (1)H detection for such a purpose is severely hampered due to significant loss of resolution in addition to indistinguishable overlap of the spectra from the two enantiomers. This study demonstrates that the band selected small flip angle homonuclear correlation experiment is a simple and robust technique that provides unambiguous discrimination, very high spectral resolution, reduced multiplicity of transitions, relative signs of the couplings and enormous saving of instrument time.

  4. Structural confirmation of regioisomers of Lopinavir impurities using MS and gradient COSY (1H and 13C NMR assignment of Lopinavir impurities).

    PubMed

    Siva Lakshmi Devi, A; Srinivasa Rao, Y; Suresh, Y; Yogeswar Reddy, M; Jyothi, G; Rajababu, B; Prasad, V S R; Umamaheswar Rao, V

    2007-05-01

    We report the complete (1)H and (13)C NMR assignment of impurities of six Lopinavir (2S)-N-[(2S, 4S, 5S)-5-{[2-(2,6-dimethylphenoxy)acetyl]amino}-4-hydroxy-1,6-diphenyl hexan-2-yl]-3-methyl-2-(2-oxo-1,3-diazinan-1-yl)butan- amide. Two of the impurities are regioisomers and GCOSY used to differentiate the two structures. The spectral assignments for all six impurities were achieved by concerted application of one and two-dimensional NMR techniques ((1)H NMR, (13)C NMR, DEPT, GCOSY, GHSQC and GHMBC). Copyright (c) 2007 John Wiley & Sons, Ltd.

  5. Substantial variation across geographic regions in the obesity prevalence among 6-8 years old Hungarian children (COSI Hungary 2016).

    PubMed

    Erdei, Gergő; Bakacs, Márta; Illés, Éva; Nagy, Barbara; Kaposvári, Csilla; Mák, Erzsébet; Nagy, Eszter Sarkadi; Cserháti, Zoltán; Kovács, Viktória Anna

    2018-05-09

    There have been previous representative nutritional status surveys conducted in Hungary, but this is the first one that examines overweight and obesity prevalence according to the level of urbanization and in different geographic regions among 6-8-year-old children. We also assessed whether these variations were different by sex. This survey was part of the fourth data collection round of World Health Organization (WHO) Childhood Obesity Surveillance Initiative which took place during the academic year 2016/2017. The representative sample was determined by two-stage cluster sampling. A total of 5332 children (48.4% boys; age 7.54 ± 0.64 years) were measured from all seven geographic regions including urban (at least 500 inhabitants per square kilometer; n = 1598), semi-urban (100 to 500 inhabitants per square kilometer; n = 1932) and rural (less than 100 inhabitants per square kilometer; n = 1802) areas. Using the WHO reference, prevalence of overweight and obesity within the whole sample were 14.2, and 12.7%, respectively. According to the International Obesity Task Force (IOTF) reference, rates were 12.6 and 8.6%. Northern Hungary and Southern Transdanubia were the regions with the highest obesity prevalence of 11.0 and 12.0%, while Central Hungary was the one with the lowest obesity rate (6.1%). The prevalence of overweight and obesity tended to be higher in rural areas (13.0 and 9.8%) than in urban areas (11.9 and 7.0%). Concerning differences in sex, girls had higher obesity risk in rural areas (OR = 2.0) but boys did not. Odds ratios were 2.0-3.4 in different regions for obesity compared to Central Hungary, but only among boys. Overweight and obesity are emerging problems in Hungary. Remarkable differences were observed in the prevalence of obesity by geographic regions. These variations can only be partly explained by geographic characteristics. Study protocol was approved by the Scientific and Research Ethics Committee of the Medical Research Council ( 61158-2/2016/EKU ).

  6. Monoterpene Unknowns Identified Using IR, [to the first power]H-NMR, [to the thirteenth power]C-NMR, DEPT, COSY, and HETCOR

    ERIC Educational Resources Information Center

    Alty, Lisa T.

    2005-01-01

    A study identifies a compound from a set of monoterpenes using infrared (IR) and one-dimensional (1D) nuclear magnetic resonance (NMR) techniques. After identifying the unknown, each carbon and proton signal can be interpreted and assigned to the structure using the information in the two-dimensional (2D) NMR spectra, correlation spectroscopy…

  7. Solution structure of a lipid transfer protein extracted from rice seeds. Comparison with homologous proteins.

    PubMed

    Poznanski, J; Sodano, P; Suh, S W; Lee, J Y; Ptak, M; Vovelle, F

    1999-02-01

    Nuclear magnetic resonance (NMR) spectroscopy was used to determine the three dimensional structure of rice nonspecific lipid transfer protein (ns-LTP), a 91 amino acid residue protein belonging to the broad family of plant ns-LTP. Sequence specific assignment was obtained for all but three HN backbone 1H resonances and for more than 95% of the 1H side-chain resonances using a combination of 1H 2D NOESY; TOCSY and COSY experiments at 293 K. The structure was calculated on the basis of four disulfide bridge restraints, 1259 distance constraints derived from 1H-1H Overhauser effects, 72 phi angle restraints and 32 hydrogen-bond restraints. The final solution structure involves four helices (H1: Cys3-Arg18, H2: Ala25-Ala37, H3: Thr41-Ala54 and H4: Ala66-Cys73) followed by a long C-terminal tail (T) with no observable regular structure. N-capping residues (Thr2, Ser24, Thr40), whose side-chain oxygen atoms are involved in hydrogen bonds with i + 3 amide proton additionally stabilize the N termini of the first three helices. The fourth helix involving Pro residues display a mixture of alpha and 3(10) conformation. The rms deviation of 14 final structures with respect to the average structure is 1.14 +/- 0.16 A for all heavy atoms (C, N, O and S) and 0.72 +/- 0.01 A for the backbone atoms. The global fold of rice ns-LTP is close to the previously published structures of wheat, barley and maize ns-LTPs exhibiting nearly identical pattern of the numerous sequence specific interactions. As reported previously for different four-helix topology proteins, hydrophobic, hydrogen bonding and electrostatic mechanisms of fold stabilization were found for the rice ns-LTP. The sequential alignment of 36 ns-LTP primary structures strongly suggests that there is a uniform pattern of specific long-range interactions (in terms of sequence), which stabilize the fold of all plant ns-LTPs.

  8. Identification of antimicrobial compound, diketopiperazines, from a Bacillus sp. N strain associated with a rhabditid entomopathogenic nematode against major plant pathogenic fungi.

    PubMed

    Nishanth Kumar, S; Mohandas, C; Siji, J V; Rajasekharan, K N; Nambisan, Bala

    2012-10-01

    To purify and characterize antimicrobial compounds from Bacillus sp. strain N associated with rhabditid entomopathogenic nematode (EPN). The cell-free culture filtrate of a bacterium associated with an EPN, Rhabditis (Oscheius) sp., exhibited strong antimicrobial activity. The ethyl acetate extract of the bacterial culture filtrate was purified by silica gel column chromatography to obtain three diketopiperazines (DKPs). The structure and absolute stereochemistry of this compound were determined based on extensive spectroscopic analyses (FABMS, (1) H NMR, (13) C NMR, (1) H-(1) H COSY, (1) H-(13) C HMBC) and Marfey's method. The compounds were identified as cyclo(l-Pro-l-Leu), cyclo(d-Pro-l-Leu) and cyclo(d-Pro-l-Tyr), respectively. Three DKPs were active against all the five fungi tested (Aspergillus flavus, Candida albicans, Fusarium oxysporum, Rhizoctonia solani and Penicillium expansum) and are more effective than the standard fungicide bavistin. The highest activity of 4 μg ml(-1) by cyclo(l-Pro-l-Leu) and cyclo(d-Pro-l-Tyr) was recorded against P. expansum, a plant pathogen responsible for causing postharvest decay of stored apples and oranges. Cyclo(d-Pro-l-Leu) recorded good antibacterial activity against all the four bacteria tested (Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa), and cyclo(l-Pro-l-Leu) and cyclo(d-Pro-l-Tyr) recorded good activity only against Gram-positive bacteria. To our knowledge, this is the first report of antifungal activity of the DKPs against the plant pathogenic fungi F. oxysporum, R. solani and P. expansum. The production of cyclo(l-Pro-l-Leu), cyclo(d-Pro-l-Leu) and cyclo-(d-Pro-l-Tyr) by a bacterium associated with EPN is also reported here for the first time. Isolated DKPs demonstrated high antimicrobial activity against bacteria and fungi, especially against plant pathogenic fungi. We conclude that the bacterium associated with EPN is a promising source of natural bioactive

  9. Identification of Hepatoprotective Constituents in Limonium tetragonum and Development of Simultaneous Analysis Method using High-performance Liquid Chromatography

    PubMed Central

    Lee, Jae Sun; Kim, Yun Na; Kim, Na-Hyun; Heo, Jeong-Doo; Yang, Min Hye; Rho, Jung-Rae; Jeong, Eun Ju

    2017-01-01

    Background: Limonium tetragonum, a naturally salt-tolerant halophyte, has been studied recently and is of much interest to researchers due to its potent antioxidant and hepatoprotective activities. Objective: In the present study, we attempted to elucidate bioactive compounds from ethyl acetate (EtOAc) soluble fraction of L. tetragonum extract. Furthermore, the simultaneous analysis method of bioactive EtOAc fraction of L. tetragonum has been developed using high-performance liquid chromatography (HPLC). Materials and Methods: Thirteen compounds have been successfully isolated from EtOAc fraction of L. tetragonum, and the structures of 1–13 were elucidated by extensive one-dimensional and two-dimensional spectroscopic methods including 1H-NMR, 13C-NMR, 1H-1H COSY, heteronuclear single quantum coherence, heteronuclear multiple bond correlation, and nuclear Overhauser effect spectroscopy. Hepatoprotection of the isolated compounds against liver fibrosis was evaluated by measuring inhibition on hepatic stellate cells (HSCs) undergoing proliferation. Results: Compounds 1–13 were identified as gallincin (1), apigenin-3-O-β-D-galactopyranoside (2), quercetin (3), quercetin-3-O-β-D-galactopyranoside (4), (−)-epigallocatechin (5), (−)-epigallocatechin-3-gallate (6), (−)-epigallocatechin-3-(3″-O-methyl) gallate (7), myricetin-3-O-β-D-galactopyranoside (8), myricetin-3-O-(6″-O-galloyl)-β-D-galactopyranoside (9), myricetin-3-O-α-L-rhamnopyranoside (10), myricetin-3-O-(2″-O-galloyl)-α-L-rhamnopyranoside (11), myricetin-3-O-(3″-O-galloyl)-α-L-rhamnopyranoside (12), and myricetin-3-O-α-L-arabinopyranoside (13), respectively. All compounds except for 4, 8, and 10 are reported for the first time from this plant. Conclusion: Myricetin glycosides which possess galloyl substituent (9, 11, and 12) showed most potent inhibitory effects on the proliferation of HSCs. SUMMARY In the present study, we have successfully isolated 13 compounds from bioactive fraction

  10. Cyclic dipeptides from rhabditid entomopathogenic nematode-associated Bacillus cereus have antimicrobial activities.

    PubMed

    Nishanth Kumar, S; Nath, Vishnu Sukumari; Pratap Chandran, R; Nambisan, Bala

    2014-02-01

    The cell free culture filtrate of Bacillus cereus associated with an entomopathogenic nematode, Rhabditis (Oscheius) sp. exhibited strong antimicrobial activity. The ethyl acetate extract of the bacterial culture filtrate was purified by silica gel column chromatography to obtain four bioactive compounds. The structure and absolute stereochemistry of these compounds were determined based on extensive spectroscopic analyses (FABMS, (1)H NMR, (13)C NMR, (1)H-(1)H COSY, (1)H-(13)C HMBC) and Marfey's method. The compounds were identified as cyclic dipeptides (CDPs): cyclo(L-Pro-L-Trp), cyclo(L-Leu-L-Val), cyclo(D-Pro-D-Met), and cyclo(D-Pro-D-Phe), respectively. Compounds recorded significant antibacterial activity against all the test bacteria (Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and methicillin-resistant S. aureus) except cyclo(L-Leu-L-Val). Cyclo(L-Leu-L-Val) recorded activity only against Gram positive bacteria. Best antibacterial activity was recorded by cyclo(L-Pro-L-Trp) against S. aureus (4 μg/ml). The four compounds were active against all the five fungi tested (Trichophyton rubrum, Aspergillus flavus, Candida albicans, Candida tropicalis and Cryptococcus neoformans) and the activity was compared with amphotericin B, the standard fungicide. The highest activity of 1 μg/ml by cyclo(L-Pro-L-Trp) was recorded against T. rubrum, a human pathogen responsible for causing athlete's foot, jock itch, and ringworm. The activity of cyclo(L-Pro-L-Trp) against T. rubrum, C. neoformans and C. albicans were better than amphotericin B, the standard antifungal agent. To our knowledge, this is the first report of antifungal activity of CDPs against the human pathogenic fungi T. rubrum and C. neoformans. The four CDPs are nontoxic to healthy human cell line up to 200 μg/ml. We conclude that the bacterium associated with entomopathogenic nematode is promising sources of natural antimicrobial

  11. Reaction of dehydropyrrolizidine alkaloids with valine and hemoglobin.

    PubMed

    Zhao, Yuewei; Wang, Shuguang; Xia, Qingsu; Gamboa da Costa, Gonçalo; Doerge, Daniel R; Cai, Lining; Fu, Peter P

    2014-10-20

    Pyrrolizidine alkaloid-containing plants are probably the most common poisonous plants affecting livestock, wildlife, and humans. Pyrrolizidine alkaloids exert toxicity through metabolism to dehydropyrrolizidine alkaloids that bind to cellular protein and DNA, leading to hepatotoxicity, genotoxicity, and tumorigenicity. To date, it is not clear how dehydropyrrolizidine alkaloids bind to cellular constituents, including amino acids and proteins, resulting in toxicity. Metabolism of carcinogenic monocrotaline, riddelliine, and heliotrine produces dehydromonocrotaline, dehyroriddelliine, and dehydroheliotrine, respectively, as primary reactive metabolites. In this study, we report that reaction of dehydromonocrotaline with valine generated four highly unstable 6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (DHP)-derived valine (DHP-valine) adducts. For structural elucidation, DHP-valine adducts were derivatized with phenyl isothiocyanate (PITC) to DHP-valine-PITC products. After HPLC separation, their structures were characterized by mass spectrometry, UV-visible spectrophotometry, (1)H NMR, and (1)H-(1)H COSY NMR spectral analysis. Two DHP-valine-PITC adducts, designated as DHP-valine-PITC-1 and DHP-valine-PITC-3, had the amino group of valine linked to the C7 position of the necine base, and the other two DHP-valine-PITC products, DHP-valine-PITC-2 and DHP-valine-PITC-4, linked to the C9 position of the necine base. DHP-valine-PITC-1 was interconvertible with DHP-valine-PITC-3, and DHP-valine-PITC-2 was interconvertible with DHP-valine-PITC-4. Reaction of dehydroriddelliine and dehydroheliotrine with valine provided similar results. However, reaction of valine and dehydroretronecine (DHR) under similar experimental conditions did not produce DHP-valine adducts. Reaction of dehydromonocrotaline with rat hemoglobin followed by derivatization with PITC also generated the same four DHP-valine-PITC adducts. This represents the first full structural elucidation of

  12. Neuroprotective Properties of Compounds Extracted from Dianthus superbus L. against Glutamate-induced Cell Death in HT22 Cells

    PubMed Central

    Yun, Bo-Ra; Yang, Hye Jin; Weon, Jin Bae; Lee, Jiwoo; Eom, Min Rye; Ma, Choong Je

    2016-01-01

    -methoxy-4-hydroxyphenylethanol (8), hydroferulic acid (9), and methyl hydroferulate (10) were isolated from D. superbus extract4-hydroxy-benzeneacetic acid and 4-methoxybenzeneacetic acid showed significant protective activity against glutamate-induced toxicity in HT22 cells. Abbreviations used: CNS: Central nervous system, ROS: Reactive oxygen species, CHCl3: Chloroform, EtOAc: Ethyl acetate, BuOH: Butanol, HPLC: High performance liquid chromatography, TLC: Thin layer chromatography, MPLC: Middle performance liquid chromatography, MeOH: Methanol, OD: Optical density, COSY: Correlation spectroscopy, HMQC: Heteronuclear multiple-quantum correlation, HMBC: Heteronuclear multiple-bond correlation, HR-MS: High-resolution molecular spectroscopy, MTT: 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. PMID:27076746

  13. Neuroprotective Properties of Compounds Extracted from Dianthus superbus L. against Glutamate-induced Cell Death in HT22 Cells.

    PubMed

    Yun, Bo-Ra; Yang, Hye Jin; Weon, Jin Bae; Lee, Jiwoo; Eom, Min Rye; Ma, Choong Je

    2016-01-01

    ) were isolated from D. superbus extract4-hydroxy-benzeneacetic acid and 4-methoxybenzeneacetic acid showed significant protective activity against glutamate-induced toxicity in HT22 cells. Abbreviations used: CNS: Central nervous system, ROS: Reactive oxygen species, CHCl3: Chloroform, EtOAc: Ethyl acetate, BuOH: Butanol, HPLC: High performance liquid chromatography, TLC: Thin layer chromatography, MPLC: Middle performance liquid chromatography, MeOH: Methanol, OD: Optical density, COSY: Correlation spectroscopy, HMQC: Heteronuclear multiple-quantum correlation, HMBC: Heteronuclear multiple-bond correlation, HR-MS: High-resolution molecular spectroscopy, MTT: 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide.

  14. Variecolactol: A New Sesterterpene Lactone from the Sclerotia of Aspergillus auricomus (Guegen) Saito

    USDA-ARS?s Scientific Manuscript database

    Variecolactol (1), a new sesterterpene lactone related to variecolin (2), has been isolated from the organic extracts of Aspergillus auricomus. Structure determination of this compound was achieved primarily through HMQC, HMBC, and NOESY experiments. The known compounds dihydropenicillic acid (3) ...

  15. Durable Fluorocarbon-Based Coatings for Aircraft

    DTIC Science & Technology

    2000-11-01

    synthesized two novel monomers, 2-fluoro-2- perfluorooctyl - 1,3-propanediol and 2-fluoro-2- perfluoro (2-ethylhexyl)-1,3-propanediol, and demonstrated that...propanediols, two branched perfluoroalkyl methanols, perfluoro -1H,1H-2-ethylhexanol (pefluoro-1-ethylpentyl methanol) and perfluoro - 1H,1H-2,2...malonates. Reduction of the perfluorinated malonates gave the perfluoroalkyl -branched 1,3-propanediols. R-OH + HBr R-Br cat. O O OCH 2CH3 OCH 2CH3 + O O

  16. Scandium complexes with the tetraphenylethylene and anthracene dianions.

    PubMed

    Ellis, John E; Minyaev, Mikhail E; Nifant'ev, Ilya E; Churakov, Andrei V

    2018-06-01

    The structural study of Sc complexes containing dianions of anthracene and tetraphenylethylene should shed some light on the nature of rare-earth metal-carbon bonding. The crystal structures of (18-crown-6)bis(tetrahydrofuran-κO)sodium bis(η 6 -1,1,2,2-tetraphenylethenediyl)scandium(III) tetrahydrofuran disolvate, [Na(C 4 H 8 O) 2 (C 12 H 24 O 6 )][Sc(C 26 H 20 ) 2 ]·2C 4 H 8 O or [Na(18-crown-6)(THF) 2 ][Sc(η 6 -C 2 Ph 4 ) 2 ]·2(THF), (1b), (η 5 -1,3-diphenylcyclopentadienyl)(tetrahydrofuran-κO)(η 6 -1,1,2,2-tetraphenylethenediyl)scandium(III) toluene hemisolvate, [Sc(C 17 H 13 )(C 26 H 20 )(C 4 H 8 O)]·0.5C 7 H 8 or [(η 5 -1,3-Ph 2 C 5 H 3 )Sc(η 6 -C 2 Ph 4 )(THF)]·0.5(toluene), (5b), poly[[(μ 2 -η 3 :η 3 -anthracenediyl)bis(η 6 -anthracenediyl)bis(η 5 -1,3-diphenylcyclopentadienyl)tetrakis(tetrahydrofuran)dipotassiumdiscandium(III)] tetrahydrofuran monosolvate], {[K 2 Sc 2 (C 14 H 10 ) 3 (C 17 H 13 ) 2 (C 4 H 8 O) 4 ]·C 4 H 8 O} n or [K(THF) 2 ] 2 [(1,3-Ph 2 C 5 H 3 ) 2 Sc 2 (C 14 H 10 ) 3 ]·THF, (6), and 1,4-diphenylcyclopenta-1,3-diene, C 17 H 14 , (3a), have been established. The [Sc(η 6 -C 2 Ph 4 ) 2 ] - complex anion in (1b) contains the tetraphenylethylene dianion in a symmetrical bis-η 3 -allyl coordination mode. The complex homoleptic [Sc(η 6 -C 2 Ph 4 ) 2 ] - anion retains its structure in THF solution, displaying hindered rotation of the coordinated phenyl rings. The 1D 1 H and 13 C{ 1 H}, and 2D COSY 1 H- 1 H and 13 C- 1 H NMR data are presented for M[Sc(Ph 4 C 2 ) 2 ]·xTHF [M = Na and x = 4 for (1a); M = K and x = 3.5 for (2a)] in THF-d 8 media. Complex (5b) exhibits an unsymmetrical bis-η 3 -allyl coordination mode of the dianion, but this changes to a η 4 coordination mode for (1,3-Ph 2 C 5 H 3 )Sc(Ph 4 C 2 )(THF) 2 , (5a), in THF-d 8 solution. A 45 Sc NMR study of (2a) and UV-Vis studies of (1a), (2a) and (5a) indicate a significant covalent contribution to the Sc-Ph 4 C 2 bond character. The unique Sc ate complex, (6

  17. Isolation, NMR studies, and biological activities of onopordopicrin from Centaurea sonchifolia.

    PubMed

    Lonergan, G; Routsi, E; Georgiadis, T; Agelis, G; Hondrelis, J; Matsoukas, J; Larsen, L K; Caplan, F R

    1992-02-01

    A sesquiterpene lactone, onopordopicrin [1], has been isolated from Centaurea sonchifolia. Its structure was established by 2D nmr (1H-1H and 13C-1H correlations), and the conformation in CHCl3 was examined by nOe studies. Cytotoxic, antibacterial, and antifungal activities are reported.

  18. Proton-Detected 15N NMR-Spectroscopy and Imaging

    NASA Astrophysics Data System (ADS)

    Freeman, D.; Sailasuta, N.; Sukumar, S.; Hurd, R. E.

    1993-10-01

    Proton detection of nitrogen-15, using gradients for coherence selection, was determined to be an effective method for obtaining spectra of 15N-labeled metabolites from extracts and biopsies of tissue infused with [15N] ammonium chloride. The advantage of gradient selection of coherence was best demonstrated by the almost complete single-shot elimination of solvent water in extracts and tissue water in biopsies. As a single-acquisition editing method in which only protons attached to 15N are detected, the potential limitations of dynamic range and motion are also reduced. Gradient-enhanced heteronuclear multiple-quantum coherence (1H[15N] HMQC) was compared with conventional HMQC, and despite selection of only one of the two heteronuclear pathways, GE-HMQC was found to be more effective for resolving the desired signal for dilute solutions; and with a single scan. In addition, effective water elimination made it possible to use the resolution advantage of a frequency-encoding dimension in proton-detected 15N imaging experiments. The limit of detection of the method at 500 MHz was 0.7 mM in 16 scans from a total volume of 400 μl. Signals from tissue extracts were observable in less than one minute for kidney, heart, brain, and muscle. Proton-detected 15N GE-HMQC images with a voxel size of 39 × 78 × 625 μm were obtained at 600 MHz from a 4 mM (1.6 μmol) 15N urea sample in less than four hours. Distribution of [15N] urea in the kidney was observed in a 600 MHz GE-HMQC image of the papilla and some cortical structures.

  19. Spectral analysis of the Crab Nebula and GRB 160530A with the Compton Spectrometer and Imager

    NASA Astrophysics Data System (ADS)

    Sleator, Clio; Boggs, Steven E.; Chiu, Jeng-Lun; Kierans, Carolyn; Lowell, Alexander; Tomsick, John; Zoglauer, Andreas; Amman, Mark; Chang, Hsiang-Kuang; Tseng, Chao-Hsiung; Yang, Chien-Ying; Lin, Chih H.; Jean, Pierre; von Ballmoos, Peter

    2017-08-01

    The Compton Spectrometer and Imager (COSI) is a balloon-borne soft gamma-ray (0.2-5 MeV) telescope designed to study astrophysical sources including gamma-ray bursts and compact objects. As a compact Compton telescope, COSI has inherent sensitivity to polarization. COSI utilizes 12 germanium detectors to provide excellent spectral resolution. On May 17, 2016, COSI was launched from Wanaka, New Zealand and completed a successful 46-day flight on NASA’s new Superpressure balloon. To perform spectral analysis with COSI, we have developed an accurate instrument model as required for the response matrix. With carefully chosen background regions, we are able to fit the background-subtracted spectra in XSPEC. We have developed a model of the atmosphere above COSI based on the NRLMSISE-00 Atmosphere Model to include in our spectral fits. The Crab and GRB 160530A are among the sources detected during the 2016 flight. We present spectral analysis of these two point sources. Our GRB 160530A results are consistent with those from other instruments, confirming COSI’s spectral abilities. Furthermore, we discuss prospects for measuring the Crab polarization with COSI.

  20. Homonuclear long-range correlation spectra from HMBC experiments by covariance processing.

    PubMed

    Schoefberger, Wolfgang; Smrecki, Vilko; Vikić-Topić, Drazen; Müller, Norbert

    2007-07-01

    We present a new application of covariance nuclear magnetic resonance processing based on 1H--13C-HMBC experiments which provides an effective way for establishing indirect 1H--1H and 13C--13C nuclear spin connectivity at natural isotope abundance. The method, which identifies correlated spin networks in terms of covariance between one-dimensional traces from a single decoupled HMBC experiment, derives 13C--13C as well as 1H--1H spin connectivity maps from the two-dimensional frequency domain heteronuclear long-range correlation data matrix. The potential and limitations of this novel covariance NMR application are demonstrated on two compounds: eugenyl-beta-D-glucopyranoside and an emodin-derivative. Copyright (c) 2007 John Wiley & Sons, Ltd.

  1. Superhydrophobic cotton fabrics prepared by sol–gel coating of TiO2 and surface hydrophobization

    PubMed Central

    Xue, Chao-Hua; Jia, Shun-Tian; Chen, Hong-Zheng; Wang, Mang

    2008-01-01

    By coating fibers with titania sol to generate a dual-size surface roughness, followed by hydrophobization with stearic acid, 1H,1H,2H,2H-perfluorodecyltrichlorosilane or their combination, hydrophilic cotton fabrics were made superhydrophobic. The surface wettability and topology of cotton fabrics were studied by contact angle measurement and scanning electron microscopy. The UV-shielding property of the treated fabrics was also characterized by UV-vis spectrophotometry. PMID:27877998

  2. Application of high-resolution, two-dimensional 1H and 13C nuclear magnetic resonance techniques to the characterization of lipid oxidation products in autoxidized linoleoyl/linolenoylglycerols.

    PubMed

    Silwood, C J; Grootveld, M

    1999-07-01

    Subjection of polyunsaturated fatty acid (PUFA)-rich culinary oils to standard frying episodes generates a range of lipid oxidation products (LOP), including saturated and alpha,beta-unsaturated aldehydes which arise from the thermally induced fragmentation of conjugated hydroperoxydiene precursors. Since such LOP are damaging to human health, we have employed high-resolution, two-dimensional 1H-1H relayed coherence transfer, 1H-1H total correlation, 1H-13C heteronuclear multiple quantum correlation, and 1H-1H J-resolved nuclear magnetic resonance (NMR) spectroscopic techniques to further elucidate the molecular structures of these components present in (i) a model linoleoylglycerol compound (1,3-dilinolein) allowed to autoxidize at ambient temperature and (ii) PUFA-rich culinary oils subjected to repeated frying episodes. The above techniques readily facilitate the resolution of selected vinylic and aldehydic resonances of LOP which appear as complex overlapping patterns in conventional one-dimensional spectra, particularly when employed in combination with solvent-induced spectral shift modifications. Hence, much useful multi-component information regarding the identity and/or classification of glycerol-bound conjugated hydroperoxydiene and hydroxydiene adducts, and saturated and alpha,beta-unsaturated aldehydes, present in autoxidized PUFA matrices is provided by these NMR methods. Such molecular information is of much value to researchers investigating the deleterious health effects of LOP available in the diet.

  3. High-resolution NMR characterization of low abundance oligomers of amyloid-β without purification

    NASA Astrophysics Data System (ADS)

    Kotler, Samuel A.; Brender, Jeffrey R.; Vivekanandan, Subramanian; Suzuki, Yuta; Yamamoto, Kazutoshi; Monette, Martine; Krishnamoorthy, Janarthanan; Walsh, Patrick; Cauble, Meagan; Holl, Mark M. Banaszak; Marsh, E. Neil. G.; Ramamoorthy, Ayyalusamy

    2015-07-01

    Alzheimer’s disease is characterized by the misfolding and self-assembly of the amyloidogenic protein amyloid-β (Aβ). The aggregation of Aβ leads to diverse oligomeric states, each of which may be potential targets for intervention. Obtaining insight into Aβ oligomers at the atomic level has been a major challenge to most techniques. Here, we use magic angle spinning recoupling 1H-1H NMR experiments to overcome many of these limitations. Using 1H-1H dipolar couplings as a NMR spectral filter to remove both high and low molecular weight species, we provide atomic-level characterization of a non-fibrillar aggregation product of the Aβ1-40 peptide using non-frozen samples without isotopic labeling. Importantly, this spectral filter allows the detection of the specific oligomer signal without a separate purification procedure. In comparison to other solid-state NMR techniques, the experiment is extraordinarily selective and sensitive. A resolved 2D spectra could be acquired of a small population of oligomers (6 micrograms, 7% of the total) amongst a much larger population of monomers and fibers (93% of the total). By coupling real-time 1H-1H NMR experiments with other biophysical measurements, we show that a stable, primarily disordered Aβ1-40 oligomer 5-15 nm in diameter can form and coexist in parallel with the well-known cross-β-sheet fibrils.

  4. High-resolution NMR characterization of low abundance oligomers of amyloid-β without purification

    PubMed Central

    Kotler, Samuel A.; Brender, Jeffrey R.; Vivekanandan, Subramanian; Suzuki, Yuta; Yamamoto, Kazutoshi; Monette, Martine; Krishnamoorthy, Janarthanan; Walsh, Patrick; Cauble, Meagan; Holl, Mark M. Banaszak; Marsh, E. Neil. G.; Ramamoorthy, Ayyalusamy

    2015-01-01

    Alzheimer’s disease is characterized by the misfolding and self-assembly of the amyloidogenic protein amyloid-β (Aβ). The aggregation of Aβ leads to diverse oligomeric states, each of which may be potential targets for intervention. Obtaining insight into Aβ oligomers at the atomic level has been a major challenge to most techniques. Here, we use magic angle spinning recoupling 1H-1H NMR experiments to overcome many of these limitations. Using 1H-1H dipolar couplings as a NMR spectral filter to remove both high and low molecular weight species, we provide atomic-level characterization of a non-fibrillar aggregation product of the Aβ1-40 peptide using non-frozen samples without isotopic labeling. Importantly, this spectral filter allows the detection of the specific oligomer signal without a separate purification procedure. In comparison to other solid-state NMR techniques, the experiment is extraordinarily selective and sensitive. A resolved 2D spectra could be acquired of a small population of oligomers (6 micrograms, 7% of the total) amongst a much larger population of monomers and fibers (93% of the total). By coupling real-time 1H-1H NMR experiments with other biophysical measurements, we show that a stable, primarily disordered Aβ1-40 oligomer 5–15 nm in diameter can form and coexist in parallel with the well-known cross-β-sheet fibrils. PMID:26138908

  5. High-resolution NMR characterization of low abundance oligomers of amyloid-β without purification.

    PubMed

    Kotler, Samuel A; Brender, Jeffrey R; Vivekanandan, Subramanian; Suzuki, Yuta; Yamamoto, Kazutoshi; Monette, Martine; Krishnamoorthy, Janarthanan; Walsh, Patrick; Cauble, Meagan; Holl, Mark M Banaszak; Marsh, E Neil G; Ramamoorthy, Ayyalusamy

    2015-07-03

    Alzheimer's disease is characterized by the misfolding and self-assembly of the amyloidogenic protein amyloid-β (Aβ). The aggregation of Aβ leads to diverse oligomeric states, each of which may be potential targets for intervention. Obtaining insight into Aβ oligomers at the atomic level has been a major challenge to most techniques. Here, we use magic angle spinning recoupling (1)H-(1)H NMR experiments to overcome many of these limitations. Using (1)H-(1)H dipolar couplings as a NMR spectral filter to remove both high and low molecular weight species, we provide atomic-level characterization of a non-fibrillar aggregation product of the Aβ1-40 peptide using non-frozen samples without isotopic labeling. Importantly, this spectral filter allows the detection of the specific oligomer signal without a separate purification procedure. In comparison to other solid-state NMR techniques, the experiment is extraordinarily selective and sensitive. A resolved 2D spectra could be acquired of a small population of oligomers (6 micrograms, 7% of the total) amongst a much larger population of monomers and fibers (93% of the total). By coupling real-time (1)H-(1)H NMR experiments with other biophysical measurements, we show that a stable, primarily disordered Aβ1-40 oligomer 5-15 nm in diameter can form and coexist in parallel with the well-known cross-β-sheet fibrils.

  6. Field electron emission based on resonant tunneling in diamond/CoSi2/Si quantum well nanostructures

    PubMed Central

    Gu, Changzhi; Jiang, Xin; Lu, Wengang; Li, Junjie; Mantl, Siegfried

    2012-01-01

    Excellent field electron emission properties of a diamond/CoSi2/Si quantum well nanostructure are observed. The novel quantum well structure consists of high quality diamond emitters grown on bulk Si substrate with a nanosized epitaxial CoSi2 conducting interlayer. The results show that the main emission properties were modified by varying the CoSi2 thickness and that stable, low-field, high emission current and controlled electron emission can be obtained by using a high quality diamond film and a thicker CoSi2 interlayer. An electron resonant tunneling mechanism in this quantum well structure is suggested, and the tunneling is due to the long electron mean free path in the nanosized CoSi2 layer. This structure meets most of the requirements for development of vacuum micro/nanoelectronic devices and large-area cold cathodes for flat-panel displays. PMID:23082241

  7. Polarimetric Analysis of the Long Duration Gamma-Ray Burst GRB 160530A With the Balloon Borne Compton Spectrometer and Imager

    SciTech Connect

    Lowell, A. W.; Boggs, S. E; Chiu, C. L.

    2017-10-20

    A long duration gamma-ray burst, GRB 160530A, was detected by the Compton Spectrometer and Imager (COSI) during the 2016 COSI Super Pressure Balloon campaign. As a Compton telescope, COSI is inherently sensitive to the polarization of gamma-ray sources in the energy range 0.2–5.0 MeV. We measured the polarization of GRB 160530A using (1) a standard method (SM) based on fitting the distribution of azimuthal scattering angles with a modulation curve and (2) an unbinned, maximum likelihood method (MLM). In both cases, the measured polarization level was below the 99% confidence minimum detectable polarization levels of 72.3% ± 0.8% (SM) andmore » 57.5% ± 0.8% (MLM). Therefore, COSI did not detect polarized gamma-ray emission from this burst. Our most constraining 90% confidence upper limit on the polarization level was 46% (MLM).« less

  8. Field electron emission based on resonant tunneling in diamond/CoSi2/Si quantum well nanostructures.

    PubMed

    Gu, Changzhi; Jiang, Xin; Lu, Wengang; Li, Junjie; Mantl, Siegfried

    2012-01-01

    Excellent field electron emission properties of a diamond/CoSi(2)/Si quantum well nanostructure are observed. The novel quantum well structure consists of high quality diamond emitters grown on bulk Si substrate with a nanosized epitaxial CoSi(2) conducting interlayer. The results show that the main emission properties were modified by varying the CoSi(2) thickness and that stable, low-field, high emission current and controlled electron emission can be obtained by using a high quality diamond film and a thicker CoSi(2) interlayer. An electron resonant tunneling mechanism in this quantum well structure is suggested, and the tunneling is due to the long electron mean free path in the nanosized CoSi(2) layer. This structure meets most of the requirements for development of vacuum micro/nanoelectronic devices and large-area cold cathodes for flat-panel displays.

  9. Phase transformations in ion-irradiated silicides

    NASA Technical Reports Server (NTRS)

    Hewett, C. A.; Lau, S. S.; Suni, I.; Hung, L. S.

    1985-01-01

    The present investigation has three objectives. The first is concerned with the phase transformation of CoSi2 under ion implantation and the subsequent crystallization characteristics during annealing, taking into account epitaxial and nonepitaxial recrystallization behavior. The second objective is related to a study of the general trend of implantation-induced damage and crystallization behavior for a number of commonly used silicides. The last objective involves a comparison of the recrystallization behavior of cosputtered refractory silicides with that of the ion-implanted silicides. It was found that epitaxial regrowth of ion-irradiated CoSi2 occurred for samples with an epitaxial seed left at the Si/CoSi2 interface. A structural investigation of CoSi2 involving transmission electron microscopy (TEM) showed that after high-dose implantation CoSi2 is amorphous.

  10. Subsurface Growth Of Silicide Structures In Silicon

    NASA Technical Reports Server (NTRS)

    Fathauer, Robert W.; George, Thomas; Pike, William T.; Schowalter, Leo

    1993-01-01

    Technique shows promise for fabrication of novel electronic, optoelectronic, and electro-optical devices. Experiments demonstrated feasibility of growing microscopic single-crystal CoSi2 structures beneath surfaces of Si substrates.

  11. Polarimetric Analysis of the Long Duration Gamma-Ray Burst GRB 160530A With the Balloon Borne Compton Spectrometer and Imager

    NASA Astrophysics Data System (ADS)

    Lowell, A. W.; Boggs, S. E.; Chiu, C. L.; Kierans, C. A.; Sleator, C.; Tomsick, J. A.; Zoglauer, A. C.; Chang, H.-K.; Tseng, C.-H.; Yang, C.-Y.; Jean, P.; von Ballmoos, P.; Lin, C.-H.; Amman, M.

    2017-10-01

    A long duration gamma-ray burst, GRB 160530A, was detected by the Compton Spectrometer and Imager (COSI) during the 2016 COSI Super Pressure Balloon campaign. As a Compton telescope, COSI is inherently sensitive to the polarization of gamma-ray sources in the energy range 0.2-5.0 MeV. We measured the polarization of GRB 160530A using (1) a standard method (SM) based on fitting the distribution of azimuthal scattering angles with a modulation curve and (2) an unbinned, maximum likelihood method (MLM). In both cases, the measured polarization level was below the 99% confidence minimum detectable polarization levels of 72.3% ± 0.8% (SM) and 57.5% ± 0.8% (MLM). Therefore, COSI did not detect polarized gamma-ray emission from this burst. Our most constraining 90% confidence upper limit on the polarization level was 46% (MLM).

  12. Differences in Visual-Spatial Input May Underlie Different Compression Properties of Firing Fields for Grid Cell Modules in Medial Entorhinal Cortex

    DTIC Science & Technology

    2015-11-19

    cortex. These features can be described through the plane equation (nx, ny, nz )(Xi, Yi, Zi) T − d = 0 with the normal vector (nx, ny, nz ) the point...operator. Using Eq 2 and Eq 3 we find the following expression for the distance Di ¼ d nx sin yi cosi þ ny sini þ nz cos yi cosi : ð5Þ Plugging in

  13. Non-uniformly weighted sampling for faster localized two-dimensional correlated spectroscopy of the brain in vivo

    NASA Astrophysics Data System (ADS)

    Verma, Gaurav; Chawla, Sanjeev; Nagarajan, Rajakumar; Iqbal, Zohaib; Albert Thomas, M.; Poptani, Harish

    2017-04-01

    Two-dimensional localized correlated spectroscopy (2D L-COSY) offers greater spectral dispersion than conventional one-dimensional (1D) MRS techniques, yet long acquisition times and limited post-processing support have slowed its clinical adoption. Improving acquisition efficiency and developing versatile post-processing techniques can bolster the clinical viability of 2D MRS. The purpose of this study was to implement a non-uniformly weighted sampling (NUWS) scheme for faster acquisition of 2D-MRS. A NUWS 2D L-COSY sequence was developed for 7T whole-body MRI. A phantom containing metabolites commonly observed in the brain at physiological concentrations was scanned ten times with both the NUWS scheme of 12:48 duration and a 17:04 constant eight-average sequence using a 32-channel head coil. 2D L-COSY spectra were also acquired from the occipital lobe of four healthy volunteers using both the proposed NUWS and the conventional uniformly-averaged L-COSY sequence. The NUWS 2D L-COSY sequence facilitated 25% shorter acquisition time while maintaining comparable SNR in humans (+0.3%) and phantom studies (+6.0%) compared to uniform averaging. NUWS schemes successfully demonstrated improved efficiency of L-COSY, by facilitating a reduction in scan time without affecting signal quality.

  14. Fabrication of photovoltaic laser energy converterby MBE

    NASA Technical Reports Server (NTRS)

    Lu, Hamilton; Wang, Scott; Chan, W. S.

    1993-01-01

    A laser-energy converter, fabricated by molecular beam epitaxy (MBE), was developed. This converter is a stack of vertical p-n junctions connected in series by low-resistivity, lattice matched CoSi2 layers to achieve a high conversion efficiency. Special high-temperature electron-beam (e-beam) sources were developed especially for the MBE growth of the junctions and CoSi2 layers. Making use of the small (greater than 1.2 percent) lattice mismatch between CoSi2 and Si layers, high-quality and pinhole-free epilayers were achieved, providing a capability of fabricating all the junctions and connecting layers as a single growth process with one pumpdown. Well-defined multiple p-n junctions connected by CoSi2 layers were accomplished by employing a low growth temperature (greater than 700 C) and a low growth rate (less than 0.5 microns/hour). Producing negligible interdiffusion, the low growth temperature and rate also produced negligible pinholes in the CoSi2 layers. For the first time, a stack of three p-n junctions connected by two 10(exp -5) Ohm-cm CoSi2 layers was achieved, meeting the high conversion efficiency requirement. This process can now be optimized for high growth rate to form a practical converter with 10 p-n junctions in the stack.

  15. Large-area Co-silicide nanodot arrays produced by colloidal nanosphere lithography and thermal annealing.

    PubMed

    Cheng, S L; Wong, S L; Lu, S W; Chen, H

    2008-09-01

    We report here the successful fabrication of large-area size-tunable periodic arrays of cobalt and Co-silicide nanodots on silicon substrates by employing the colloidal nanosphere lithography (NSL) technique and heat treatments. The growth of low-resistivity epitaxial CoSi(2) was found to be more favorable for the samples with smaller Co nanodot sizes. The sizes of the epitaxial CoSi(2) nanodots can be tuned from 50 to 100 nm by varying the diameter of the colloidal spheres and annealing temperatures. The epitaxial CoSi(2) nanodots were found to grow with an epitaxial orientation with respect to the (001)Si substrates: [001]CoSi(2)//[001]Si and (200)CoSi(2)//(400)Si. From the results of planview HRTEM, XTEM, and SAED analysis, the epitaxial CoSi(2) nanodots were identified to be inverse pyramids in shape, and the average sizes of the faceted silicide nanodots were measured to decrease with annealing temperature. The observed results present the exciting prospect that with appropriate controls, the colloidal NSL technique promises to facilitate the growth of a variety of well-ordered silicide nanodots with selected shape, size, and periodicity.

  16. New pregnane glycosides from Gymnema sylvestre.

    PubMed

    Xu, Rui; Yang, Yu; Zhang, Yang; Ren, Fengxia; Xu, Jinlong; Yu, Nengjiang; Zhao, Yimin

    2015-02-12

    Four new pregnane glycosides 1-4 were isolated from the ethanol extract of the stem of Gymnema sylvestre and named gymsylvestrosides A-D. Hydrolysis of compound 1 under the catalysis of Aspergilus niger β-glucosidase afforded compound 5 (gymsylvestroside E). Their structures were determined by spectroscopic methods such as HRESIMS, 1D and 2D NMR, as well as HMQC-TOCSY experiment. Compounds 1-4 were screened for Saccharomyces cerevisiae α-glucosidase inhibitory activity.

  17. In Vivo Detection of 15N-Coupled Protons in Rat Brain by ISIS Localization and Multiple-Quantum Editing

    NASA Astrophysics Data System (ADS)

    Kanamori, Keiko; Ross, Brian D.

    1999-08-01

    Three-dimensional image-selected in vivo spectroscopy (ISIS) was combined with phase-cycled 1H-15N heteronuclear multiple-quantum coherence (HMQC) transfer NMR for localized selective observation of protons J-coupled to 15N in phantoms and in vivo. The ISIS-HMQC sequence, supplemented by jump-return water suppression, permitted localized selective observation of 2-5 μmol of [15Nindole]tryptophan, a precursor of the neurotransmitter serotonin, through the 15N-coupled proton in 20-40 min of acquisition in vitro at 4.7 T. In vivo, the amide proton of [5-15N]glutamine was selectively observed in the brain of spontaneously breathing 15NH4+-infused rats, using a volume probe with homogeneous 1H and 15N fields. Signal recovery after three-dimensional localization was 72-82% in phantoms and 59 ± 4% in vivo. The result demonstrates that localized selective observation of 15N-coupled protons, with complete cancellation of all other protons except water, can be achieved in spontaneously breathing animals by the ISIS-HMQC sequence. This sequence performs both volume selection and heteronuclear editing through an addition/subtraction scheme and predicts the highest intrinsic sensitivity for detection of 15N-coupled protons in the selected volume. The advantages and limitations of this method for in vivo application are compared to those of other localized editing techniques currently in use for non-exchanging protons.

  18. Comparison of various NMR methods for the indirect detection of nitrogen-14 nuclei via protons in solids

    NASA Astrophysics Data System (ADS)

    Shen, Ming; Trébosc, Julien; O'Dell, Luke A.; Lafon, Olivier; Pourpoint, Frédérique; Hu, Bingwen; Chen, Qun; Amoureux, Jean-Paul

    2015-09-01

    We present an experimental comparison of several through-space Hetero-nuclear Multiple-Quantum Correlation experiments, which allow the indirect observation of homo-nuclear single- (SQ) or double-quantum (DQ) 14N coherences via spy 1H nuclei. These 1H-{14N} D-HMQC sequences differ not only by the order of 14N coherences evolving during the indirect evolution, t1, but also by the radio-frequency (rf) scheme used to excite and reconvert these coherences under Magic-Angle Spinning (MAS). Here, the SQ coherences are created by the application of center-band frequency-selective pulses, i.e. long and low-power rectangular pulses at the 14N Larmor frequency, ν0(14N), whereas the DQ coherences are excited and reconverted using rf irradiation either at ν0(14N) or at the 14N overtone frequency, 2ν0(14N). The overtone excitation is achieved either by constant frequency rectangular pulses or by frequency-swept pulses, specifically Wide-band, Uniform-Rate, and Smooth-Truncation (WURST) pulse shapes. The present article compares the performances of four different 1H-{14N} D-HMQC sequences, including those with 14N rectangular pulses at ν0(14N) for the indirect detection of homo-nuclear (i) 14N SQ or (ii) DQ coherences, as well as their overtone variants using (iii) rectangular or (iv) WURST pulses. The compared properties include: (i) the sensitivity, (ii) the spectral resolution in the 14N dimension, (iii) the rf requirements (power and pulse length), as well as the robustness to (iv) rf offset and (v) MAS frequency instabilities. Such experimental comparisons are carried out for γ-glycine and L-histidine.HCl monohydrate, which contain 14N sites subject to moderate quadrupole interactions. We demonstrate that the optimum choice of the 1H-{14N} D-HMQC method depends on the experimental goal. When the sensitivity and/or the robustness to offset are the major concerns, the D-HMQC sequence allowing the indirect detection of 14N SQ coherences should be employed. Conversely

  19. Determination of fluorotelomer alcohols in selected consumer products and preliminary investigation of their fate in the indoor environment.

    PubMed

    Liu, Xiaoyu; Guo, Zhishi; Folk, Edgar E; Roache, Nancy F

    2015-06-01

    The U.S. Environmental Protection Agency (EPA) has established an ongoing effort to identify the major perfluorocarboxylic acid (PFCA) sources in nonoccupational indoor environments and characterize their transport and fate. This study determined the concentrations of fluorotelomer alcohols (FTOHs), which are the precursors to PFCAs, in fifty-four consumer products collected from the U.S. open market in the years of 2011 and 2013. The products included carpet, commercial carpet-care liquids, household carpet/fabric-care liquids, treated apparel, treated home textiles, treated non-woven medical garments, floor waxes, food-contact paper, membranes for apparel, and thread-sealant tapes. The FTOHs quantified were 1H,1H,2H,2H-perfluoro-1-octanol (6:2 FTOH), 1H,1H,2H,2H-perfluoro-1-decanol (8:2 FTOH), and 1H,1H,2H,2H-perfluoro-1-dodecanol (10:2 FTOH). The content of 6:2 FTOH ranged from non-delectable to 331μgg(-1), 8:2 FTOH from non-delectable to 92μgg(-1), and 10:2 FTOH from non-detectable to 24μgg(-1). In addition, two consumer products from the home textile category were tested in the washing-drying process. One product from the treated apparel category and one from the home textile category were tested in the micro-scale chamber under elevated temperatures. The experimental data show that the washing-drying process with one cycle did not significantly reduce the FTOH concentrations in the tested consumer products. FTOH off-gassing was observed under accelerated aging conditions. Future tests should include air sampling to allow determination of the absolute emission rates at different temperatures. The results of this study should be informative to exposure assessment and risk management. Published by Elsevier Ltd.

  20. SciTech Connect

    Singh, Mukhtiyar; Saini, Hardev S.; Thakur, Jyoti

    Heusler alloys based thin-films often exhibit a degree of atomic disorder which leads to the lowering of spin polarization in spintronic devices. We present ab-initio calculations of atomic disorder effects on spin polarization and half-metallicity of Mn{sub 2}CoSi inverse Heusler alloy. The five types of disorder in Mn{sub 2}CoSi have been proposed and investigated in detail. The A2{sub a}-type and B2-type disorders destroy the half-metallicity whereas it sustains for all disorders concentrations in DO{sub 3a}- and A2{sub b}-type disorder and for smallest disorder concentration studied in DO{sub 3b}-type disorder. Lower formation energy/atom for A2{sub b}-type disorder than other four disordersmore » in Mn{sub 2}CoSi advocates the stability of this disorder. The total magnetic moment shows a strong dependence on the disorder and the change in chemical environment. The 100% spin polarization even in the presence of disorders explicitly supports that these disorders shall not hinder the use of Mn{sub 2}CoSi inverse Heusler alloy in device applications. - Graphical abstract: Minority-spin gap (E{sub g↓}) and HM gap (E{sub sf}) as a function of concentrations of various possible disorder in Mn{sub 2}CoSi inverse Heusler alloy. The squares with solid line (black color)/dotted line (blue color)/dashed line (red color) reperesents E{sub g↓} for DO{sub 3a}-/DO{sub 3b}-/A2{sub b}-type disorder in Mn{sub 2}CoSi and the spheres with solid line (black color)/dottedline (blue color)/dashed line (red color) represents E{sub sf} for DO{sub 3a}-/DO{sub 3b}-/A2{sub b}-type disorder in Mn{sub 2}CoSi. - Highlights: • The DO{sub 3}- and A2-type disorders do not affect the half-metallicity in Mn{sub 2}CoSi. • The B2-type disorder solely destroys half-metallicity in Mn{sub 2}CoSi. • The A2-type disorder most probable to occur out of all three types. • The total spin magnetic moment strongly depends on the disorder concentrations.« less

  1. Fluoroalkylated Silicon-Containing Surfaces - Estimation of Solid Surface Energy

    DTIC Science & Technology

    2010-10-20

    surface tension liquids such as octane (γlv = 21.6 mN/m) and methanol (γlv = 22.7 mN/m), requires an appropriately chosen surface micro/nano-texture in...addition to a low solid surface energy (γsv). 1H,1H,2H,2H- Heptadecafluorodecyl polyhedral oligomeric silsesquioxane (fluorodecyl POSS) offers one of...27.5 mN/m), while Girifalco-Good analysis was performed using a set of polar and non-polar liquids with a wider range of liquid surface tension (15.5

  2. Predicting the NMR spectra of nucleotides by DFT calculations: cyclic uridine monophosphate.

    PubMed

    Bagno, Alessandro; Rastrelli, Federico; Saielli, Giacomo

    2008-06-01

    We present an experimental and quantum chemical NMR study of the mononucleotide cyclic uridine monophosphate in water. Spectral parameters ((1)H and (13)C chemical shifts and (1)H--(1)H, (13)C--(1)H, (31)P--(13)C and (31)P--(1)H spin-spin coupling constants) have been carefully obtained experimentally and calculated using DFT methods including the solvent effect and the conformational flexibility of the solute. This study confirms that the (1)H and (13)C spectra of polar, flexible molecules in aqueous solution can be predicted with a high level of accuracy, comparable to that obtained for less complex systems. Copyright (c) 2008 John Wiley & Sons, Ltd

  3. A new C-Glycosylflavone from Encyclia michuacana

    NASA Astrophysics Data System (ADS)

    Tovar-Gijón, Claudia E.; Hernández-Carlos, Beatriz; Burgueño-Tapia, Eleuterio; Cedillo-Portugal, Ernestina; Joseph-Nathan, Pedro

    2006-02-01

    The methanol extracts from Encyclia michuacana tubercles yielded the new 8- C-(6-deoxy-β- D-glucopyranosyl)apigenin ( 1) together with known 1-(3'-hydroxy-5'-methoxyphenyl)-2-(4″-hydroxy-5″-methoxyphenyl)ethane ( 2) and 2-(4-hydroxybenzyl)malic acid ( 3). The new structure was elucidated using spectroscopic methods, mainly 1D and 2D NMR. The β-anomer for 1 was supported by comparison of the experimental 1H- 1H coupling constant values with those generated employing a generalized Karplus-type relationship using dihedral angles extracted from DFT calculations.

  4. 1H and 13C NMR Chemical Shift Assignments and Conformational Analysis for the Two Diastereomers of the Vitamin K Epoxide Reductase Inhibitor Brodifacoum

    SciTech Connect

    Cort, John R.; Cho, Herman M.

    2009-10-01

    Proton and 13C NMR chemical shift assignments and 1H-1H scalar couplings for the two diastereomers of the vitamin K epoxide reductase (VKOR) inhibitor brodifacoum have been determined from acetone solutions containing both diastereomers. Data were obtained from homo- and heteronuclear correlation spectra acquired at 1H frequencies of 750 and 900 MHz over a 268-303 K temperature range. Conformations inferred from scalar coupling and 1-D NOE measurements exhibit large differences between the diastereomers. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  5. DFT molecular modeling and NMR conformational analysis of a new longipinenetriolone diester

    NASA Astrophysics Data System (ADS)

    Cerda-García-Rojas, Carlos M.; Guerra-Ramírez, Diana; Román-Marín, Luisa U.; Hernández-Hernández, Juan D.; Joseph-Nathan, Pedro

    2006-05-01

    The structure and conformational behavior of the new natural compound (4 R,5 S,7 S,8 R,9 S,10 R,11 R)-longipin-2-en-7,8,9-triol-1-one 7-angelate-9-isovalerate (1) isolated from Stevia eupatoria, were studied by molecular modeling and NMR spectroscopy. A Monte Carlo search followed by DFT calculations at the B3LYP/6-31G* level provided the theoretical conformations of the sesquiterpene framework, which were in full agreement with results derived from the 1H- 1H coupling constant analysis.

  6. Isolation and structure elucidation of the nucleoside antibiotic strepturidin from Streptomyces albus DSM 40763.

    PubMed

    Pesic, Alexander; Steinhaus, Britta; Kemper, Sebastian; Nachtigall, Jonny; Kutzner, Hans Jürgen; Höfle, Gerhard; Süssmuth, Roderich D

    2014-06-01

    The antibiotic strepturidin (1) was isolated from the microorganism Streptomyces albus DSM 40763, and its structure elucidated by spectroscopic methods and chemical degradation studies. The determination of the relative and absolute stereocenters was partially achieved using chiral GC/EI-MS analysis and microderivatization by acetal ring formation and subsequent 2D-NMR analysis of key (1)H,(1)H-NOESY NMR correlations and extraction of (1)H,(13)C coupling constants from (1)H,(13)C-HMBC NMR spectra. Based on these results, a biosynthesis model was proposed.

  7. Effects of strain on the half-metallicity and spin gapless feature of Ti2YSi (Y = Fe, Co) alloys

    NASA Astrophysics Data System (ADS)

    Fan, Xiaoguang; Li, Jincheng; Jin, Yingjiu

    2018-05-01

    Half-metals and spin gapless semiconductors (SGSs), which exhibit 100% spin polarization at the Fermi level, are considered important candidates for spintronics. Using first-principles calculations, we have investigated the effects of uniform strain and tetragonal distortion on the half-metallicity and spin gapless feature of inverse Heusler Ti2YSi (Y = Fe and Co) alloys. Results show that for uniform strains, the half-metallicity occurs in the ranges of lattice parameters from 5.938 Å to 6.535 Å for Ti2FeSi and from 5.924 Å to 6.840 Å for Ti2CoSi. Tetragonal distortions over the ranges of ‑2.0% to +2.5% and ‑2.6% to +4.1% could destroy the half-metallicity for Ti2FeSi and Ti2CoSi, respectively. On the other hand, Ti2CoSi is an SGS at lattice constants of 5.968-6.023 Å. An interesting finding is that Ti2CoSi reproduces the SGS character with increasing the lattice parameters to 6.784-6.840 Å. Small tetragonal distortions with ±0.2% will destroy the SGS character of Ti2CoSi.

  8. Work function characterization of solution-processed cobalt silicide

    DOE PAGES

    Ullah, Syed Shihab; Robinson, Matt; Hoey, Justin; ...

    2012-05-08

    Cobalt silicide thin films were prepared by spin-coating Si6H12-based inks onto various substrates followed by a thermal treatment. The work function of the solution processed Co-Si was determined by both capacitance-voltage (C-V) measurements of metal-oxide-semiconductor (MOS) structures as well as by ultraviolet photoelectron spectroscopy (UPS). The UPS-derived work function was 4.80 eV for a Co-Si film on Si (100) while C-V of MOS structures yielded a work function of 4.36 eV where the metal was solution-processed Co-Si, the oxide was SiO2 and the semiconductor was a B-doped Si wafer.

  9. Proton-proton elastic scattering excitation functions at intermediate energies

    NASA Astrophysics Data System (ADS)

    Rohdjess, H.

    1998-05-01

    Polarized and unpolarized proton-proton elastic scattering is investigated with the EDDA-experiment at the Cooler Synchrotron COSY at Jülich to significantly improve the world data base in the beam energy range 500-2500 MeV. Measurements during beam acceleration with thin internal targets and a large acceptance detector provide excitation functions over a broad angular and energy range with unprecedented internal consistency. Data taking with an unpolarized CH2 fiber target and an unpolarized beam have been completed and the derived differential cross sections are presented and compared to a recent phase shift analysis. With a polarized atomic beam target newly installed in COSY and a polarized COSY beam—currently under development—the measurements will be extended to analyzing powers and spin correlation parameters.

  10. Partial-wave analysis of nucleon-nucleon elastic scattering data

    DOE PAGES

    Workman, Ron L.; Briscoe, William J.; Strakovsky, Igor I.

    2016-12-19

    Energy-dependent and single-energy fits to the existing nucleon-nucleon database have been updated to incorporate recent measurements. The fits cover a region from threshold to 3 GeV, in the laboratory kinetic energy, for proton-proton scattering, with an upper limit of 1.3 GeV for neutron-proton scattering. Experiments carried out at the COSY-WASA and COSY-ANKE facilities have had a significant impact on the partial-wave solutions. Lastly, results are discussed in terms of both partial-wave and direct reconstruction amplitudes.

  11. SciTech Connect

    Workman, Ron L.; Briscoe, William J.; Strakovsky, Igor I.

    Energy-dependent and single-energy fits to the existing nucleon-nucleon database have been updated to incorporate recent measurements. The fits cover a region from threshold to 3 GeV, in the laboratory kinetic energy, for proton-proton scattering, with an upper limit of 1.3 GeV for neutron-proton scattering. Experiments carried out at the COSY-WASA and COSY-ANKE facilities have had a significant impact on the partial-wave solutions. Lastly, results are discussed in terms of both partial-wave and direct reconstruction amplitudes.

  12. New irradiation facilities for development of production methods of medical radionuclides at cyclotrons at Forschungszentrum Jülich

    NASA Astrophysics Data System (ADS)

    Spellerberg, S.; Scholten, B.; Spahn, I.; Felden, O.; Gebel, R.; Qaim, S. M.; Bai, M.; Neumaier, B.

    2017-05-01

    An essential basis for research and development work on radiopharmaceuticals is the efficient production of radionuclides of high quality. In this process research-oriented studies aiming for elucidation of biochemical processes require novel products. The radionuclide development at INM-5 entails basic research, e.g. the determination of nuclear reaction data, as well as technical aspects of practical production, such as high-current targetry, chemical separation, formulation and quality control. In this work developments, adaptation and optimization of irradiation facilities at the BC 1710, JULIC as Injector of COSY and COSY itself are summarized, which shall allow the extension of radionuclide production possibilities, aiming at innovations in medical applications.

  13. Polarization-independent dual-band terahertz metamaterial absorbers based on gold/parylene-C/silicide structure.

    PubMed

    Wen, Yongzheng; Ma, Wei; Bailey, Joe; Matmon, Guy; Yu, Xiaomei; Aeppli, Gabriel

    2013-07-01

    We design, fabricate, and characterize dual-band terahertz (THz) metamaterial absorbers with high absorption based on structures consisting of a cobalt silicide (Co-Si) ground plane, a parylene-C dielectric spacer, and a metal top layer. By combining two periodic metal resonators that couple separately within a single unit cell, a polarization-independent absorber with two distinct absorption peaks was obtained. By varying the thickness of the dielectric layer, we obtain absorptivity of 0.76 at 0.76 THz and 0.97 at 2.30 THz, which indicates the Co-Si ground plane absorbers present good performance.

  14. A Novel Multivoxel-Based Quantitation of Metabolites and Lipids Noninvasively Combined with Diffusion-Weighted Imaging in Breast Cancer

    DTIC Science & Technology

    2012-09-01

    scanner. Report of the Progress: Multi-slice DWI-MRI and 4D EP-COSI was tested in 2 malignant and 3 benign breast cancer patients and 6 healthy...for improving the overall specificity. • We are currently testing retrospective Maximum Entropy and Compressed Sensing of the 4D EP-COSI data so that...MRS. NMR in Biomed. 2008;22(1):77-91. 2 Kobus T, Vos PC, Hambrock T, De Rooij M, Hulsbergen-Van de Kaa CA, Barentsz JO, Heerschap A, Scheenen TW

  15. Structural Modulation from 1D Chain to 3D Framework: Improved Thermostability, Insensitivity, and Energies of Two Nitrogen-Rich Energetic Coordination Polymers.

    PubMed

    Guo, Zhaoqi; Wu, Yunlong; Deng, Chongqing; Yang, Guoping; Zhang, Jiangong; Sun, Zhihua; Ma, Haixia; Gao, Chao; An, Zhongwei

    2016-11-07

    Two new energetic coordination polymers (CPs) [Pb(BT)(H 2 O) 3 ] n (1) and [Pb 3 (DOBT) 3 (H 2 O) 2 ] n ·(4H 2 O) n (2) with 1D and 3D structures were synthesized by employing two rational designed ligands, 1H,1'H-5,5'-bitetrazole (H 2 BT) and 1H,1'H-[5,5'-bitetrazole]-1,1'-diol ligands (DHBT), respectively. Thermal analyses and sensitivity tests show that the 3D architecture reinforces the network of 2 which has higher thermal stability and lower sensitivity than that of 1. Through oxygen-bomb combustion calorimetry the molar enthalpy of formation of 2 is derived to be much higher than that of 1 as well as the reported CPs. Herein, more importantly, the heats of detonation (ΔH det ) were calculated according to the decomposition products of TG-DSC-MS-FTIR simultaneous analyses for the first time. The calculated results show that ΔH det of 2 is 23% higher than that of 1. This research demonstrates that 3D energetic CP with outstanding energetic properties can be obtained through efficient and reasonable design.

  16. Sensitizing solid state nuclear magnetic resonance of dilute nuclei by spin-diffusion assisted polarization transfers.

    PubMed

    Lupulescu, Adonis; Frydman, Lucio

    2011-10-07

    Recent years have witnessed efforts geared at increasing the sensitivity of NMR experiments, by relying on the suitable tailoring and exploitation of relaxation phenomena. These efforts have included the use of paramagnetic agents, enhanced (1)H-(1)H incoherent and coherent transfers processes in 2D liquid state spectroscopy, and homonuclear (13)C-(13)C spin diffusion effects in labeled solids. The present study examines some of the opportunities that could open when exploiting spontaneous (1)H-(1)H spin-diffusion processes, to enhance relaxation and to improve the sensitivity of dilute nuclei in solid state NMR measurements. It is shown that polarization transfer experiments executed under sufficiently fast magic-angle-spinning conditions, enable a selective polarization of the dilute low-γ spins by their immediate neighboring protons. Repolarization of the latter can then occur during the time involved in monitoring the signal emitted by the low-γ nuclei. The basic features involved in the resulting approach, and its potential to improve the effective sensitivity of solid state NMR measurements on dilute nuclei, are analyzed. Experimental tests witness the advantages that could reside from utilizing this kind of approach over conventional cross-polarization processes. These measurements also highlight a number of limitations that will have to be overcome for transforming selective polarization transfers of this kind into analytical methods of choice. © 2011 American Institute of Physics

  17. Smart, Sustainable, and Ecofriendly Chemical Design of Fully Bio-Based Thermally Stable Thermosets Based on Benzoxazine Chemistry.

    PubMed

    Froimowicz, Pablo; R Arza, Carlos; Han, Lu; Ishida, Hatsuo

    2016-08-09

    A smart synthetic chemical design incorporating furfurylamine, a natural renewable amine, into a partially bio-based coumarin-containing benzoxazine is presented. The versatility of the synthetic approach is shown to be flexible and robust enough to be successful under more ecofriendly reaction conditions by replacing toluene with ethanol as the reaction solvent and even under solventless conditions. The chemical structure of this coumarin-furfurylamine-containing benzoxazine is characterized by FTIR, (1) H NMR spectroscopy and two-dimensional (1) H-(1) H nuclear Overhauser effect spectroscopy (2D (1) H-(1) H NOESY). The thermal properties of the resin toward polymerization are characterized by differential scanning calorimetry (DSC) and the thermal stability of the resulting polymers by thermogravimetric analysis (TGA). The results reveal that the furanic moiety induces a co-operative activating effect, thus lowering the polymerization temperature and also contributes to a better thermal stability of the resulting polymers. These results, in addition to those of natural renewable benzoxazine resins reviewed herein, highlight the positive and beneficial implication of designing novel bio-based polybenzoxazine and possibly other thermosets with desirable and competitive properties. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Trace level detection of compounds related to the chemical weapons convention by 1H-detected 13C NMR spectroscopy executed with a sensitivity-enhanced, cryogenic probehead.

    PubMed

    Cullinan, David B; Hondrogiannis, George; Henderson, Terry J

    2008-04-15

    Two-dimensional 1H-13C HSQC (heteronuclear single quantum correlation) and fast-HMQC (heteronuclear multiple quantum correlation) pulse sequences were implemented using a sensitivity-enhanced, cryogenic probehead for detecting compounds relevant to the Chemical Weapons Convention present in complex mixtures. The resulting methods demonstrated exceptional sensitivity for detecting the analytes at trace level concentrations. 1H-13C correlations of target analytes at < or = 25 microg/mL were easily detected in a sample where the 1H solvent signal was approximately 58,000-fold more intense than the analyte 1H signals. The problem of overlapping signals typically observed in conventional 1H spectroscopy was essentially eliminated, while 1H and 13C chemical shift information could be derived quickly and simultaneously from the resulting spectra. The fast-HMQC pulse sequences generated magnitude mode spectra suitable for detailed analysis in approximately 4.5 h and can be used in experiments to efficiently screen a large number of samples. The HSQC pulse sequences, on the other hand, required roughly twice the data acquisition time to produce suitable spectra. These spectra, however, were phase-sensitive, contained considerably more resolution in both dimensions, and proved to be superior for detecting analyte 1H-13C correlations. Furthermore, a HSQC spectrum collected with a multiplicity-edited pulse sequence provided additional structural information valuable for identifying target analytes. The HSQC pulse sequences are ideal for collecting high-quality data sets with overnight acquisitions and logically follow the use of fast-HMQC pulse sequences to rapidly screen samples for potential target analytes. Use of the pulse sequences considerably improves the performance of NMR spectroscopy as a complimentary technique for the screening, identification, and validation of chemical warfare agents and other small-molecule analytes present in complex mixtures and environmental

  19. NMR analysis of cleaved Escherichia coli thioredoxin (1-73/74-108) and its P76A variant: cis/trans peptide isomerization.

    PubMed Central

    Yu, W. F.; Tung, C. S.; Wang, H.; Tasayco, M. L.

    2000-01-01

    Inspection of high resolution three-dimensional (3D) structures from the protein database reveals an increasing number of cis-Xaa-Pro and cis-Xaa-Yaa peptide bonds. However, we are still far from being able to predict whether these bonds will remain cis upon single-site substitution of Pro or Yaa and/or cleavage of a peptide bond close to it in the sequence. We have chosen oxidized Escherichia coli thioredoxin (Trx), a member of the Trx superfamily with a single alpha/beta domain and cis P76 to determine the effect of single-site substitution and/or cleavage on this isomer. Standard two-dimensional (2D) NMR analysis were performed on cleaved Trx (1-73/74-108) and its P76A variant. Analysis of the NOE connectivities indicates remarkable similarity between the secondary and supersecondary structure of the noncovalent complexes and Trx. Analysis of the 2D version of the HCCH-TOCSY and HMQC-NOESY-HMQC and 13C-filtered HMQC-NOESY spectra of cleaved Trx with uniformly 13C-labeled 175 and P76 shows surprising conservation of both cis P76 and packing of 175 against W31. A similar NMR analysis of its P76A variant provides no evidence for cis A76 and shows only subtle local changes in both the packing of 175 and the interstrand connectivities between its most protected hydrophobic strands (beta2 and beta4). Indeed, a molecular simulation model for the trans P76A variant of Trx shows only subtle local changes around the substitution site. In conclusion, cleavage of R73 is insufficient to provoke cis/trans isomerization of P76, but cleavage and single-site substitution (P76A) favors the trans isomer. PMID:10739243

  20. Novel dimeric metabolites from Alternaria tagetica.

    PubMed

    Gamboa-Angulo, M M; Alejos-González, F; Escalante-Erosa, F; García-Sosa, K; Delgado-Lamas, G; Peña-Rodríguez, L M

    2000-08-01

    Two novel polyketides, bis-7-O-8' '.8-O-7' '- and bis-7-O-7' '. 8-O-8' '-zinniol (2 and 3, respectively) were isolated from the organic crude extract of culture filtrates from Alternaria tagetica. Both structures were determined on the basis of their spectroscopic data (IR, MS, (1)H NMR, (13)C NMR, and 2D NMR experiments) and confirmed by chemical synthesis. Zinniol (1) was isolated as a major component, and its (13)C NMR data was correctly assigned after careful analysis of data from its 2D NMR experiments (HMQC and HMBC).

  1. Emotion Education without Ontological Commitment?

    ERIC Educational Resources Information Center

    Kristjansson, Kristjan

    2010-01-01

    Emotion education is enjoying new-found popularity. This paper explores the "cosy consensus" that seems to have developed in education circles, according to which approaches to emotion education are immune from metaethical considerations such as contrasting rationalist and sentimentalist views about the moral ontology of emotions. I spell out five…

  2. A complete 1H and 13C NMR data assignment for the diterpene methyl (-)-zanzibarate by 2D spectroscopy and NOE experiments.

    PubMed

    Imamura, P M; Miranda, P C M L; Giacomini, R A

    2004-06-01

    The 1H and 13C NMR spectra of methyl (-)-zanzibarate (1), an ent-labdanic diterpene isolated from the epicarp of Hymenaea courbaril var. altissima (Leguminosaea, Cesalpinoideae, Detariae), was fully assigned by COSY experiments, 13C/1H shift correlation diagrams and NOE experiments. Copyright 2004 John Wiley & Sons, Ltd.

  3. Translations on Telecommunications Policy, Research and Development No. 48

    DTIC Science & Technology

    1978-08-02

    BRENCI, P. F. CHECCACCI, F. COSI, R. FALCIAI, A. M. SCHEGGI: Progressi nella tecnologia delle fibre ottiche in silice plastica realizzate presso...notably for signaling-toward subscribers with digital equipment, or for common channel systems as well. It also includes 3D registers that require

  4. Unidirectional endotaxial cobalt di-silicide nanowires on Si(110) substrates

    NASA Astrophysics Data System (ADS)

    Mahato, J. C.; Das, Debolina; Banu, Nasrin; Satpati, Biswarup; Dev, B. N.

    2017-10-01

    Self-organized growth of well-ordered endotaxial silicide nanowires (NWs) on clean Si(110) surfaces has been investigated by in situ scanning tunneling microscopy (STM) and transmission electron microscopy (TEM). Co deposition on clean Si(110) reconstructed surfaces at ∼600 °C produces unidirectional CoSi2 NWs by reaction of cobalt with the hot silicon substrate. STM investigations reveal four major types of distinct NWs, all growing along the [-110] in-plane direction except one type growing along the in-plane [-113] direction. There are also some nanodots. The cross-sectional TEM measurements show that the unidirectional NWs are of two types—flat-top and ridged. The NWs grow not only on the substrate but also into the substrate. CoSi2 in flat top NWs are in the same crystallographic orientation as the substrate Si and the buried interfaces between CoSi2 and Si are A-type. In the ridged NWs CoSi2 and Si are in different crystallographic orientations and the interfaces are B-type. The ridged NWs are in general wider and grow deeper into the substrate.

  5. Computer-Mediated Communications Systems: Will They Catch On?

    ERIC Educational Resources Information Center

    Cook, Dave; Ridley, Michael

    1990-01-01

    Describes the use of CoSy, a computer conferencing system, by academic librarians at McMaster University in Ontario. Computer-mediated communications systems (CMCS) are discussed, the use of the system for electronic mail and computer conferencing is described, the perceived usefulness of CMCS is examined, and a sidebar explains details of the…

  6. Application of the Yoshida-Ruth Techniques to Implicit Integration and Multi-Map Explicit Integration

    SciTech Connect

    Forest, E.; Bengtsson, J.; Reusch, M.F.

    1991-04-01

    The full power of Yoshida's technique is exploited to produce an arbitrary order implicit symplectic integrator and multi-map explicit integrator. This implicit integrator uses a characteristic function involving the force term alone. Also we point out the usefulness of the plain Ruth algorithm in computing Taylor series map using the techniques first introduced by Berz in his 'COSY-INFINITY' code.

  7. Aligning Olympic Education with the Liberal Arts: A Curriculum Blueprint from Taiwan

    ERIC Educational Resources Information Center

    Hsu, Li-Hong Leo; Kohe, Geoffery Zain

    2015-01-01

    Background: For some time the Olympics have enjoyed a relatively cosy, and quite unsurprising, relationship with Physical Education and its practitioners. Yet, as academics continue their critiques of all matters Olympic, this seemingly symbiotic partnership is being placed under much closer scrutiny. The debates are typically orientated around…

  8. Electronic Structure and Thermoelectric Properties of Transition Metal Monosilicides

    NASA Astrophysics Data System (ADS)

    Pshenay-Severin, D. A.; Ivanov, Yu. V.; Burkov, A. T.; Novikov, S. V.; Zaitsev, V. K.; Reith, H.

    2018-06-01

    We present theoretical and experimental results on electronic structure and thermoelectric properties of cobalt monosilicide (CoSi) and of Co1- x M x Si diluted alloys (M = Fe and Ni) at temperatures from 2 K to 800 K. CoSi crystallizes into a non-centrosymmetric cubic B20 structure, which suggests the possibility of a topologically non-trivial electronic structure. We show that the electronic structure of CoSi exhibits linear band crossings in close vicinity to Fermi energy, confirming the possibility of non-trivial topology. The proximity of the linear-dispersion bands to Fermi energy implies their important contribution to the electronic transport. Calculation of thermopower of CoSi, using ab initio band structure and the constant relaxation time approximation, is carried out. It reveals that many body corrections to the electronic spectrum are important in order to obtain qualitative agreement of theoretical and experimental temperature dependences of thermopower. Phonon dispersion and lattice thermal conductivity are calculated. The phonons give a major contribution to the thermal conductivity of the compound below room temperature.

  9. A Profiling System for the Assessment of Individual Needs for Rehabilitation With Hearing Aids.

    PubMed

    Dreschler, Wouter A; de Ronde-Brons, I

    2016-11-04

    This study focuses on the development of a profiling system to specify the needs of hearing-aid candidates. As a basis for the profile of compensation needs, we used a slightly modified version of the Amsterdam Inventory of Disability and Handicap, combined with the well-known Client-Oriented Scale of Improvement (COSI). The first questionnaire results in scores for six audiological dimensions: detection, speech in quiet, speech in noise, localization, focus or discrimination, and noise tolerance. The goal of this study was to determine whether the six dimensions derived from the disability questionnaire are appropriate to also categorize individual COSI targets. The results show a good agreement between eight audiologists in the categorization of COSI goals along the six dimensions. The results per dimension show that the dimension focus or discrimination can be regarded as superfluous. Possible additional dimensions were tinnitus and listening effort. The results indicate that it is possible to translate individual user needs (administered using COSI) into more general dimensions derived from a disability questionnaire. This allows to summarize the compensation needs for individual patients in a profile of general dimensions, based on the degree of disability and the individual user needs. This profile can be used as a starting point in hearing aid selection. This approach also offers a well-structured method for the evaluation of the postfitting results. © The Author(s) 2016.

  10. Updated analysis of NN elastic scattering to 3 GeV

    NASA Astrophysics Data System (ADS)

    Arndt, R. A.; Briscoe, W. J.; Strakovsky, I. I.; Workman, R. L.

    2007-08-01

    A partial-wave analysis of NN elastic scattering data has been updated to include a number of recent measurements. Experiments carried out at the Cooler Synchrotron (COSY) by the EDDA Collaboration have had a significant impact above 1 GeV. Results are discussed in terms of the partial-wave and direct-reconstruction amplitudes.

  11. Unidirectional endotaxial cobalt di-silicide nanowires on Si(110) substrates.

    PubMed

    Mahato, J C; Das, Debolina; Banu, Nasrin; Satpati, Biswarup; Dev, B N

    2017-10-20

    Self-organized growth of well-ordered endotaxial silicide nanowires (NWs) on clean Si(110) surfaces has been investigated by in situ scanning tunneling microscopy (STM) and transmission electron microscopy (TEM). Co deposition on clean Si(110) reconstructed surfaces at ∼600 °C produces unidirectional CoSi 2 NWs by reaction of cobalt with the hot silicon substrate. STM investigations reveal four major types of distinct NWs, all growing along the [-110] in-plane direction except one type growing along the in-plane [-113] direction. There are also some nanodots. The cross-sectional TEM measurements show that the unidirectional NWs are of two types-flat-top and ridged. The NWs grow not only on the substrate but also into the substrate. CoSi 2 in flat top NWs are in the same crystallographic orientation as the substrate Si and the buried interfaces between CoSi 2 and Si are A-type. In the ridged NWs CoSi 2 and Si are in different crystallographic orientations and the interfaces are B-type. The ridged NWs are in general wider and grow deeper into the substrate.

  12. Columnar and subsurface silicide growth with novel molecular beam epitaxy techniques

    NASA Technical Reports Server (NTRS)

    Fathauer, R. W.; George, T.; Pike, W. T.

    1992-01-01

    We have found novel growth modes for epitaxial CoSi2 at high temperatures coupled with Si-rich flux ratios or low deposition rates. In the first of these modes, codeposition of metal and Si at 600-800 C with excess Si leads to the formation of epitaxial silicide columns surrounded by single-crystal Si. During the initial stages of the deposition, the excess Si grows homoepitaxially in between the silicide, which forms islands, so that the lateral growth of the islands is confined. Once a template layer is established by this process, columns of silicide form as a result of selective epitaxy of silicide on silicide and Si on Si. This growth process allows nanometer control over silicide particles in three dimensions. In the second of these modes, a columnar silicide seed layer is used as a template to nucleate subsurface growth of CoSi2. With a 100 nm Si layer covering CoSi2 seeds, Co deposited at 800C and 0.01 nm/s diffuses down to grow on the buried seeds rather than nucleating surface silicide islands. For thicker Si caps or higher deposition rates, the surface concentration of Co exceeds the critical concentration for nucleation of islands, preventing this subsurface growth mode from occurring. Using this technique, single-crystal layers of CoSi2 buried under single-crystal Si caps have been grown.

  13. The Italian Version of the Cognitive Style Indicator and Its Association with Decision-Making Preferences

    ERIC Educational Resources Information Center

    Miceli, Silvana; de Palo, Valeria; Monacis, Lucia; Cardaci, Maurizio; Sinatra, Maria

    2018-01-01

    The Cognitive Style Indicator (CoSI) includes 3 cognitive dimensions: creating (flexible, open-ended and inventive), knowing (emphasizing facts, details, objectivity, and rationality), and planning (guided by preferences for certainty and well-structured information). The first aim of this research was to validate the 3-factor structure of the…

  14. 1H and 13C NMR spectra of C-6 and C-9 substituted 3-azabicyclco[3.3.1]nonanes.

    PubMed

    Goodall, Kirsten; Brimble, Margaret; Barker, David

    2008-01-01

    The 1H and 13C NMR data for 3-azabicyclo[3.3.1]nonanes with OH and OMe substituents at C-6 and C-9 were measured using 1D (DEPT) and 2D (COSY, HSQC, HMBC, NOESY) experiments. Comparison of this NMR data illustrates the effects of stereochemistry and substitution at these positions. Copyright (c) 2007 John Wiley & Sons, Ltd.

  15. Positional calibrations of the germanium double sided strip detectors for the Compton spectrometer and imager

    NASA Astrophysics Data System (ADS)

    Lowell, A.; Boggs, S.; Chiu, J. L.; Kierans, C.; McBride, S.; Tseng, C. H.; Zoglauer, A.; Amman, M.; Chang, H. K.; Jean, P.; Lin, C. H.; Sleator, C.; Tomsick, J.; von Ballmoos, P.; Yang, C. Y.

    2016-08-01

    The Compton Spectrometer and Imager (COSI) is a medium energy gamma ray (0.2 - 10 MeV) imager designed to observe high-energy processes in the universe from a high altitude balloon platform. At its core, COSI is comprised of twelve high purity germanium double sided strip detectors which measure particle interaction energies and locations with high precision. This manuscript focuses on the positional calibrations of the COSI detectors. The interaction depth in a detector is inferred from the charge collection time difference between the two sides of the detector. We outline our previous approach to this depth calibration and also describe a new approach we have recently developed. Two dimensional localization of interactions along the faces of the detector (x and y) is straightforward, as the location of the triggering strips is simply used. However, we describe a possible technique to improve the x/y position resolution beyond the detector strip pitch of 2 mm. With the current positional calibrations, COSI achieves an angular resolution of 5.6 +/- 0.1 degrees at 662 keV, close to our expectations from simulations.

  16. Calculation of incubation period and serial interval from multiple outbreaks of Marburg virus disease.

    PubMed

    Pavlin, Boris I

    2014-12-13

    Marburg viruses have been responsible for a number of outbreaks throughout sub-Saharan Africa, as well as a number of laboratory infections. Despite many years of experience with the viruses, little is known about several important epidemiologic parameters relating to the development of Marburg virus disease. The analysis uses pooled data from all Marburg cases between 1967 and 2008 to develop estimates for the incubation period and the clinical onset serial interval (COSI). Data were obtained from original outbreak investigation forms (n=406) and from published data (n=45). Incubation periods were calculated for person-to-person exposure, for laboratory-acquired infections, and for presumed zoonotic exposures. Similar analysis was conducted for COSI, using only cases with unambiguous person-to-person transmission where both the primary and the secondary case patients had well-defined illness onsets. Seventy-six cases were retained for the incubation period analysis. Incubation periods ranged from a minimum of 2 days in the case of two laboratory workers to a maximum of at least 26 days for a person-to-person household transmission. Thirty-eight cases were retained for COSI analysis. The median COSI was 11 days, with an interquartile range of 8 to 15. This study extends the maximum known incubation period of Marburg virus disease to 26 days. The analysis was severely hampered by a lack of completeness in epidemiologic data. It is necessary to prioritize obtaining more accurate epidemiologic data in future outbreaks; greater use of COSI may facilitate an improved understanding of outbreak dynamics in Marburg and other diseases.

  17. Exploring the functional mealtime associations of older adults through consumer segmentation and a means-end chain approach.

    PubMed

    den Uijl, Louise C; Jager, Gerry; de Graaf, Cees; Kremer, Stefanie

    2016-12-01

    Senior consumers are a rapidly growing and highly heterogeneous part of the world's population. This group does not always meet its recommended protein intake, which can negatively impact on their physical functioning and quality of life. To date, little is known about their motivations to consume protein-rich meals. In the current study, we therefore aim to identify consumer segments within the group of vital community-dwelling older adults on the basis of mealtime functionality (for example 'I eat because I'm hungry', or 'I eat because it is cosy'). To this end, we first conducted an online survey to identify these functional mealtime expectations of older consumers (study I, n = 398, 158 males, mean age 65.8 (y) ± 5.9 (SD)). To obtain further insights regarding mealtime functionality and proteins/protein enrichment, laddering interviews were conducted with a subgroup of the segmentation study participants (study II, n = 40, 20 males, mean age 66.9 (y) ± 4.8 (SD)). The results of the online survey showed three consumer clusters: cosy socialisers, physical nutritioners, and thoughtless rewarders. Thoughtless rewarders tend to eat without having explicit thoughts about it, they eat for the reward, and score highest on environmental awareness. Both the segmentation and the in-depth interviews showed that, for the cosy socialisers, the cosiness and social function of a meal are important motivators, whereas for the physical nutritioners the focus is more on the health and nutrient aspects of a meal. For cosy socialisers, protein enrichment can best be achieved through addition of protein-rich ingredients, whereas, for physical nutritioners, addition of protein powder is preferred. These results provide practical guidelines for the development of protein-rich meals and communication strategies tailored to the needs of specific vital community-dwelling older subgroups. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Indirect detection of infinite-speed MAS solid-state NMR spectra

    NASA Astrophysics Data System (ADS)

    Perras, Frédéric A.; Venkatesh, Amrit; Hanrahan, Michael P.; Goh, Tian Wei; Huang, Wenyu; Rossini, Aaron J.; Pruski, Marek

    2017-03-01

    Heavy spin-1/2 nuclides are known to possess very large chemical shift anisotropies that can challenge even the most advanced magic-angle-spinning (MAS) techniques. Wide manifolds of overlapping spinning sidebands and insufficient excitation bandwidths often obfuscate meaningful spectral information and force the use of static, low-resolution solid-state (SS)NMR methods for the characterization of materials. To address these issues, we have merged fast-magic-angle-turning (MAT) and dipolar heteronuclear multiple-quantum coherence (D-HMQC) experiments to obtain D-HMQC-MAT pulse sequences which enable the rapid acquisition of 2D SSNMR spectra that correlate isotropic 1H chemical shifts to the indirectly detected isotropic "infinite-MAS" spectra of heavy spin-1/2 nuclides. For these nuclides, the combination of fast MAS and 1H detection provides a high sensitivity, which rivals the DNP-enhanced ultra-wideline SSNMR. The new pulse sequences were used to determine the Pt coordination environments in a complex mixture of decomposition products of transplatin and in a metal-organic framework with Pt ions coordinated to the linker ligands.

  19. Indirect detection of infinite-speed MAS solid-state NMR spectra

    SciTech Connect

    Perras, Frédéric A.; Venkatesh, Amrit; Hanrahan, Michael P.

    Heavy spin-1/2 nuclides are known to possess very large chemical shift anisotropies that can challenge even the most advanced magic-angle-spinning (MAS) techniques. Wide manifolds of overlapping spinning sidebands and insufficient excitation bandwidths often obfuscate meaningful spectral information and force the use of static, low-resolution solid-state (SS)NMR methods for the characterization of materials. In order to address these issues, we have merged fast-magic-angle-turning (MAT) and dipolar heteronuclear multiple-quantum coherence (D-HMQC) experiments to obtain D-HMQC-MAT pulse sequences which enable the rapid acquisition of 2D SSNMR spectra that correlate isotropic 1H chemical shifts to the indirectly detected isotropic “infinite-MAS” spectra of heavy spin-1/2more » nuclides. Furthermore, for these nuclides, the combination of fast MAS and 1H detection provides a high sensitivity, which rivals the DNP-enhanced ultra-wideline SSNMR. The new pulse sequences were used to determine the Pt coordination environments in a complex mixture of decomposition products of transplatin and in a metal-organic framework with Pt ions coordinated to the linker ligands.« less

  20. Indirect detection of infinite-speed MAS solid-state NMR spectra

    DOE PAGES

    Perras, Frédéric A.; Venkatesh, Amrit; Hanrahan, Michael P.; ...

    2017-01-18

    Heavy spin-1/2 nuclides are known to possess very large chemical shift anisotropies that can challenge even the most advanced magic-angle-spinning (MAS) techniques. Wide manifolds of overlapping spinning sidebands and insufficient excitation bandwidths often obfuscate meaningful spectral information and force the use of static, low-resolution solid-state (SS)NMR methods for the characterization of materials. In order to address these issues, we have merged fast-magic-angle-turning (MAT) and dipolar heteronuclear multiple-quantum coherence (D-HMQC) experiments to obtain D-HMQC-MAT pulse sequences which enable the rapid acquisition of 2D SSNMR spectra that correlate isotropic 1H chemical shifts to the indirectly detected isotropic “infinite-MAS” spectra of heavy spin-1/2more » nuclides. Furthermore, for these nuclides, the combination of fast MAS and 1H detection provides a high sensitivity, which rivals the DNP-enhanced ultra-wideline SSNMR. The new pulse sequences were used to determine the Pt coordination environments in a complex mixture of decomposition products of transplatin and in a metal-organic framework with Pt ions coordinated to the linker ligands.« less

  1. NMR crystallography of campho[2,3-c]pyrazole (Z' = 6): combining high-resolution 1H-13C solid-state MAS NMR spectroscopy and GIPAW chemical-shift calculations.

    PubMed

    Webber, Amy L; Emsley, Lyndon; Claramunt, Rosa M; Brown, Steven P

    2010-09-30

    (1)H-(13)C two-dimensional magic-angle spinning (MAS) solid-state NMR correlation spectra, recorded with the MAS-J-HMQC experiment, are presented for campho[2,3-c]pyrazole. For each (13)C moiety, there are six resonances associated with the six distinct molecules in the asymmetric unit cell (Z' = 6). The one-bond C-H correlations observed in the 2D (1)H-(13)C MAS-J-HMQC spectra allow the experimental determination of the (1)H and (13)C chemical shifts associated with the separate CH, CH(2), and CH(3) groups. (1)H and (13)C chemical shifts calculated by using the GIPAW (Gauge Including Projector Augmented Waves) plane-wave pseudopotential approach are presented. Calculations for the whole unit cell (12 × 29 = 348 atoms, with geometry optimization of all atoms) allow the assignment of the experimental (1)H and (13)C chemical shifts to the six distinct molecules. The calculated chemical shifts for the full crystal structure are compared with those for isolated molecules as extracted from the geometry-optimized crystal structure. In this way, the effect of intermolecular interactions on the observed chemical shifts is quantified. In particular, the calculations are sufficiently precise to differentiate the small (<1 ppm) differences between the (1)H chemical shifts of the six resonances associated with each distinct CH or CH(2) moiety.

  2. Improving reliability of chemometric models for authentication of species origin of heparin by switching from 1D to 2D NMR experiments.

    PubMed

    Monakhova, Yulia B; Fareed, Jawed; Yao, Yiming; Diehl, Bernd W K

    2018-05-10

    Nuclear magnetic resonance (NMR) spectroscopy is regarded as one of the most powerful and versatile analytical approaches to assure the quality of heparin preparations. In particular, it was recently demonstrated that by using 1 H NMR coupled with chemometrics heparin and low molecular weight heparin (LMWH) samples derived from three major animal species (porcine, ovine and bovine) can be differentiated [Y.B. Monakhova et al. J. Pharm. Anal. 149 (2018) 114-119]. In this study, significant improvement of existing chemometric models was achieved by switching to 2D NMR experiments (heteronuclear multiple-quantum correlation (HMQC) and diffusion-ordered spectroscopy (DOSY)). Two representative data sets (sixty-nine heparin and twenty-two LMWH) belonged to different batches and distributed by different commercial companies were investigated. A trend for animal species differentiation was observed in the principal component analysis (PCA) score plot built based on the DOSY data. A superior model was constructed using HMQC experiments, where individual heparin (LMWH) clusters as well as their blends were clearly differentiated. The predictive power of different classification methods as well as unsupervised techniques (independent components analysis, ICA) clearly proved applicability of the model for routine heparin and LMWH analysis. The switch from 1D to 2D NMR techniques provides a wealth of additional information, which is beneficial for multivariate modeling of NMR spectroscopic data for heparin preparations. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Selective observation of biologically important 15N-labeled metabolites in isolated rat brain and liver by 1H-detected multiple-quantum-coherence spectroscopy

    NASA Astrophysics Data System (ADS)

    Kanamori, Keiko; Ross, Brian D.; Parivar, Farhad

    Four cerebral metabolites of importance in neurotransmission, serotonin, L-tryptophan, L-glutamine, and N-acetyl- L-aspartate, and two hepatic urea-cycle intermediates, citrulline and urea, were found to be observable by 1H- 15N heteronuclear multiple-quantum-coherence (HMQC) spectroscopy in aqueous solution at physiological pH and temperature, through the protons spin-coupled to their indole, amide, or ureido nitrogen. Their 1H chemical shifts were well dispersed over a 5-10 ppm region while the 1J 15N- 1H values were 87-99 Hz. For [γ- 15N]glutamine, a 50- to 100-fold increase in sensitivity over direct 15N detection was achieved, in contrast to a 2-fold increase by the polarization-transfer method. In the isolated brain of portacaval-shunted rats, the amide protons of biologically 15N-enriched [γ- 15N]glutamine were observed in 2 min of acquisition, with suppression of proton signals from all other cerebral metabolites. In isolated liver of 15N-enriched control rats, [ 15NIurea protons were observed in 16 min. The HMQC method is likely to be effective for the in vivo study of cerebral and hepatic nitrogen metabolism.

  4. Amide proton spin-lattice relaxation in polypeptides. A field-dependence study of the proton and nitrogen dipolar interactions in alumichrome.

    PubMed

    Llinás, M; Klein, M P; Wüthrich, K

    1978-12-01

    The proton nuclear magnetic resonance (NMR) spin-lattice relaxation of all six amides of deferriferrichrome and of various alumichromes dissolved in hexadeutero-dimethylsulfoxide have been investigated at 100, 220, and 360 MHz. We find that, depending on the type of residue (glycyl or ornithyl), the amide proton relaxation rates are rather uniform in the metal-free cyclohexapeptide. In contrast, the (1)H spinlattice relaxation times (T(1)'s) are distinct in the Al(3+)-coordination derivative. Similar patterns are observed in a number of isomorphic alumichrome homologues that differ in single-site residue substitutions, indicating that the spin-lattice relaxation rate is mainly determined by dipole-dipole interactions within a rigid molecular framework rather than by the specific primary structures. Analysis of the data in terms of (1)H-(1)H distances (r) calculated from X-ray coordinates yields a satisfactory linear fit between T(1) (-1) and Sigmar(-6) at the three magnetic fields. Considering the very sensitive r-dependence of T(1), the agreement gives confidence, at a quantitative level, both on the fitness of the crystallographic model to represent the alumichromes' solution conformation and on the validity of assuming isotropic rotational motion for the globular metallopeptides. An extra contribution to the amide proton T(1) (-1) is proposed to mainly originate from the (1)H-(14)N dipolar interaction: this was supported by comparison with measurements on an (15)N-enriched peptide. The nitrogen dipolar contribution to the peptide proton relaxation is discussed in the context of {(1)H}-(1)H nuclear Overhauser enhancement (NOE) studies because, especially at high fields, it can be dominant in determining the amide proton relaxation rates and hence result in a decreased effectiveness for the (1)H-(1)H dipolar mechanism to cause NOE's. From the slope and intersect values of T(1) (-1) vs. Sigmar(-6) linear plots, a number of independent estimates of tau(r), the

  5. Front End Spectroscopy ASIC for Germanium Detectors

    NASA Astrophysics Data System (ADS)

    Wulf, Eric

    Large-area, tracking, semiconductor detectors with excellent spatial and spectral resolution enable exciting new access to soft (0.2-5 MeV) gamma-ray astrophysics. The improvements from semiconductor tracking detectors come with the burden of high density of strips and/or pixels that require high-density, low-power, spectroscopy quality readout electronics. CMOS ASIC technologies are a natural fit to this requirement and have led to high-quality readout systems for all current semiconducting tracking detectors except for germanium detectors. The Compton Spectrometer and Imager (COSI), formerly NCT, at University of California Berkeley and the Gamma-Ray Imager/Polarimeter for Solar flares (GRIPS) at Goddard Space Flight Center utilize germanium cross-strip detectors and are on the forefront of NASA's Compton telescope research with funded missions of long duration balloon flights. The development of a readout ASIC for germanium detectors would allow COSI to replace their discrete electronics readout and would enable the proposed Gamma-Ray Explorer (GRX) mission utilizing germanium strip-detectors. We propose a 3-year program to develop and test a germanium readout ASIC to TRL 5 and to integrate the ASIC readout onto a COSI detector allowing a TRL 6 demonstration for the following COSI balloon flight. Our group at NRL led a program, sponsored by another government agency, to produce and integrate a cross-strip silicon detector ASIC, designed and fabricated by Dr. De Geronimo at Brookhaven National Laboratory. The ASIC was designed to handle the large (>30 pF) capacitance of three 10 cm^2 detectors daisy-chained together. The front-end preamplifier, selectable inverter, shaping times, and gains make this ASIC compatible with a germanium cross-strip detector as well. We therefore have the opportunity and expertise to leverage the previous investment in the silicon ASIC for a new mission. A germanium strip detector ASIC will also require precise timing of the signals at

  6. Cobalt disilicide contacts to silicon-germanium alloys

    NASA Astrophysics Data System (ADS)

    Goeller, Peter Thomas

    This dissertation investigated the structure and stability of thin (18--45 nm) cobalt disilicide films, electron beam evaporated onto strained and relaxed Si1--xGex/Si(001) alloy layers. The aim of these investigations was to develop a means of growing smooth, continuous, epitaxial and thermally stable CoSi2 films suitable for use as contacts in SiGe device technology. Previous research on the reaction of Co metal with SiGe alloys has indicated a number of problems, such as film islanding, formation of polycrystalline silicide films, Ge segregation and poor thermal stability. In the present work, we studied the scientific issues underlying these phenomena with a variety of experimental techniques. Our initial studies comparing direct deposition of Co versus co-deposition of Co and Si indicated that co-deposition resulted in CoSi2 formation at much lower temperatures (500°C) than with the direct deposition method (700°C). Furthermore, the co-deposited films were epitaxial to the SiGe layer, whereas the direct deposited films were polycrystalline. Both methods resulting in increasing islanding of the films with increasing annealing temperature. The issues underlying the islanding of the co-deposited films were investigated with an in situ XAFS investigation of the Co/SiGe interface using monolayers of Co. It was determined that Co preferentially bonds with Si atoms as the annealing temperature is increased, leading to segregation of Ge at the interface and faceting of the silicide. A modified template method of silicide growth was devised, in which a sacrificial Si layer was deposited onto the SiGe surface before the CoSi2 template was grown. This growth method was shown to result in smooth, epitaxial and thermally stable films of CoSi2 on Si0.80Ge0.20 alloys. A thickness effect was observed for the direct deposition of Co on SiGe alloys, in which Co layers do not completely convert to CoSi2 until thicknesses greater than 35 nm are deposited. A thermodynamic model

  7. SciTech Connect

    Rajkumar, K.; Rajavel, K.; Cameron, D. C.

    This paper reports the electrowetting properties of liquid droplet on superhydrophobic silicon nanowires with Atomic layer deposited (ALD) Al{sub 2}O{sub 3} as dielectric layer. Silicon wafer were etched by metal assisted wet chemical etching with silver as catalyst. ALD Al{sub 2}O{sub 3} films of 10nm thickness were conformally deposited over silicon nanowires. Al{sub 2}O{sub 3} dielectric film coated silicon nanowires was chemically modified with Trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane to make it superhydrophobic(SHP). The contact angle was measured and all the samples exhibited superhydrophobic nature with maximum contact angles of 163° and a minimum contact angle hysteresis of 6°.more » Electrowetting induced a maximum reversible decrease of the contact angle of 20°at 150V in air.« less

  8. Thiol-yne click reactions on alkynyl-dopamine-modified reduced graphene oxide.

    PubMed

    Kaminska, Izabela; Qi, Wang; Barras, Alexandre; Sobczak, Janusz; Niedziolka-Jonsson, Joanna; Woisel, Patrice; Lyskawa, Joel; Laure, William; Opallo, Marcin; Li, Musen; Boukherroub, Rabah; Szunerits, Sabine

    2013-06-24

    The large-scale preparation of graphene is of great importance due to its potential applications in various fields. We report herein a simple method for the simultaneous exfoliation and reduction of graphene oxide (GO) to reduced GO (rGO) by using alkynyl-terminated dopamine as the reducing agent. The reaction was performed under mild conditions to yield rGO functionalized with the dopamine derivative. The chemical reactivity of the alkynyl function was demonstrated by post-functionalization with two thiolated precursors, namely 6-(ferrocenyl)hexanethiol and 1H,1H,2H,2H-perfluorodecanethiol. X-ray photoelectron spectroscopy, UV/Vis spectrophotometry, Raman spectroscopy, conductivity measurements, and cyclic voltammetry were used to characterize the resulting surfaces. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. A novel diarylheptanoid-bearing sesquiterpene moiety from the rhizomes of Alpinia officinarum.

    PubMed

    Wei, Na; Zhou, Zhonglin; Wei, Qing; Wang, Yong; Jiang, Jun; Zhang, Junqing; Wu, Lixiang; Dai, Shuiping; Li, Youbin

    2016-10-01

    A new diarylheptanoid analogue-bearing sesquiterpene moiety, named Alpinisin A, was isolated from the rhizomes of Alpinia officinarum Hance. The new structure was determined by various spectroscopic techniques (1)H-nuclear magnetic resonance ((1)H NMR), (13)C-attached proton test ((13)C-APT), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond correlation (HMBC), (1)H-(1)H correlation spectroscopy ((1)H-(1)HCOSY), nuclear overhauser effect spectroscopy (NOESY) and high resolution electrospray ionization mass spectrometry (HR-ESI-MS). The compound was tested for cytotoxic activity in vitro against human tumour cell lines (gastric carcinoma cell -7901 (SGC-7901), Michigan Cancer Foundation-7 (MCF-7) and Caski), which showed significant inhibitory effects with IC50 levels of 11.42, 15.14 and 14.78 μM, respectively. The novel chemical structure characterised with a diarylheptanoid linked to a chain-like sesquiterpenoid should be highlighted.

  10. Amphiphilic Fluorinated Polymer Nanoparticle Film Formation and Dissolved Oxygen Sensing Application

    NASA Astrophysics Data System (ADS)

    Gao, Yu; Zhu, Huie; Yamamoto, Shunsuke; Miyashita, Tokuji; Mitsuishi, Masaya

    2016-04-01

    Fluorinated polymer nanoparticle films were prepared by dissolving amphiphilic fluorinated polymer, poly (N-1H, 1H-pentadecafluorooctylmethacrylamide) (pC7F15MAA) in two miscible solvents (AK-225 and acetic acid). A superhydrophobic and porous film was obtained by dropcasting the solution on substrates. With higher ratios of AK-225 to acetic acid, pC7F15MAA was densified around acetic acid droplets, leading to the formation of pC7F15MAA nanoparticles. The condition of the nanoparticle film preparation was investigated by varying the mixing ratio or total concentration. A highly sensitive dissolved oxygen sensor system was successfully prepared utilizing a smart surface of superhydrophobic and porous pC7F15MAA nanoparticle film. The sensitivity showed I0/I40 = 126 in the range of dissolved oxygen concentration of 0 ~ 40 mg L-1. The oxygen sensitivity was compared with that of previous reports.

  11. Thalassospiramide G, a new γ-amino-acid-bearing peptide from the marine bacterium Thalassospira sp.

    PubMed

    Um, Soohyun; Pyee, Yuna; Kim, Eun-Hee; Lee, Sang Kook; Shin, Jongheon; Oh, Dong-Chan

    2013-02-26

    In the chemical investigation of marine unicellular bacteria, a new peptide, thalassospiramide G (1), along with thalassospiramides A and D (2-3), was discovered from a large culture of Thalassospira sp. The structure of thalassospiramide G, bearing γ-amino acids, such as 4-amino-5-hydroxy-penta-2-enoic acid (AHPEA), 4-amino-3,5-dihydroxy-pentanoic acid (ADPA), and unique 2-amino-1-(1H-indol-3-yl) ethanone (AIEN), was determined via extensive spectroscopic analysis. The absolute configuration of thalassospiramide D (3), including 4-amino-3-hydroxy-5-phenylpentanoic acid (AHPPA), was rigorously determined by 1H-1H coupling constant analysis and chemical derivatization. Thalassospiramides A and D (2-3) inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated mouse macrophage RAW 264.7 cells, with IC(50) values of 16.4 and 4.8 μM, respectively.

  12. Structures and biological activities of azaphilones produced by Penicillium sp. KCB11A109 from a ginseng field.

    PubMed

    Son, Sangkeun; Ko, Sung-Kyun; Kim, Jong Won; Lee, Jae Kyoung; Jang, Mina; Ryoo, In-Ja; Hwang, Gwi Ja; Kwon, Min Cheol; Shin, Kee-Sun; Futamura, Yushi; Hong, Young-Soo; Oh, Hyuncheol; Kim, Bo Yeon; Ueki, Masashi; Takahashi, Shunji; Osada, Hiroyuki; Jang, Jae-Hyuk; Ahn, Jong Seog

    2016-02-01

    Twelve metabolites, including five highly oxygenated azaphilones, geumsanols A-E, along with seven known analogues were isolated from Penicillium sp. KCB11A109, a fungus derived from a ginseng field. Their structures were assigned by spectroscopic means (NMR and MS), and stereochemistries were determined by extensive spectroscopic analyses ((1)H-(1)H coupling constants, NOESY, and HETLOC) and chemical derivatizations (modified Mosher's method and acetonide formation). The isolates were evaluated for their anticancer, antimicrobial, antimalarial activities, and phenotypic effects in zebrafish development. Of these compounds possessing no pyranoquinone core, only geumsanol E exhibited cytotoxic activities and toxic effects on zebrafish embryos, suggesting that a double bond at C-11 and C-12 is important for biological activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Impact of surface wettability on S-layer recrystallization: a real-time characterization by QCM-D

    PubMed Central

    Vianna, Ana C; Moreno-Cencerrado, Alberto; Pum, Dietmar; Sleytr, Uwe B

    2017-01-01

    Quartz crystal microbalance with dissipation monitoring (QCM-D) has been employed to study the assembly and recrystallization kinetics of isolated SbpA bacterial surface proteins onto silicon dioxide substrates of different surface wettability. Surface modification by UV/ozone oxidation or by vapor deposition of 1H,1H,2H,2H-perfluorododecyltrichlorosilane yielded hydrophilic or hydrophobic samples, respectively. Time evolution of frequency and dissipation factors, either individually or combined as the so-called Df plots, showed a much faster formation of crystalline coatings for hydrophobic samples, characterized by a phase-transition peak at around the 70% of the total mass adsorbed. This behavior has been proven to mimic, both in terms of kinetics and film assembly steps, the recrystallization taking place on an underlying secondary cell-wall polymer (SCWP) as found in bacteria. Complementary atomic force microscopy (AFM) experiments corroborate these findings and reveal the impact on the final structure achieved. PMID:28144568

  14. Influence of solvent on micellar morphologies of semifluorinated block copolymers.

    PubMed

    Lee, Min Young; Kim, Sang Jae; Jeong, Yeon Tae; Kim, Joo Hyun; Gal, Yeong-Soon; Lim, Kwon Taek

    2009-12-01

    The influence of solvents on micellar architectures of block copolymers composed of poly(1H,1H-dihydroperfluorooctyl methacrylate) and poly(ethylene oxide) was investigated. In this study, binary solvents with desired proportions were chosen, which had remarkable influence on the morphology of the resulting micelles. With simple adjusting the composition of the binary solvent of chloroform and trichlorofluoromethane, interesting shapes of micelle-like aggregates, such as core-shell, cylinder, worm-like and inverted micelles were formed with sizes of 15, 70, 30 and 250 nm, respectively. In the case of methanol/water system, core-shell spheres and vesicles were produced by varying the proportion of the contents. The morphologies were also tuned to honeycomb-like and bowl-shaped micelles as well as large planar lamellae with holes in DMF and water binary solvent.

  15. Characterization of an antibiotic produced by Bacillus subtilis JW-1 that suppresses Ralstonia solanacearum.

    PubMed

    Kwon, Jae Won; Kim, Shin Duk

    2014-01-01

    Bacillus subtilis JW-1 was isolated from rhizosphere soil as a potential biocontrol agent of bacterial wilt caused by Ralstonia solanacearum. Seed treatment followed by a soil drench application with this strain resulted in >80% reduction in bacterial wilt disease compared with that in the untreated control under greenhouse conditions. The antibacterial compound produced by strain JW-1 was purified by bioactivity-guided fractionation. Based on mass spectroscopy and nuclear magnetic resonance spectral data ((1)H, (13)C, (1)H-(1)H correlation spectroscopies, rotating frame nuclear Overhauser effect spectroscopy, and heteronuclear multiple-bond correlation spectroscopy), the structure of this compound was elucidated as a cyclic lipopeptide composed of a heptapeptide (Gln-Leu-Leu-Val-Asp-Leu-Leu) bonded to a β-hydroxy-iso-hexadecanoic acid arranged in a lactone ring system.

  16. The second lightest CP-even Higgs boson signals in the NMSSM at the LHC

    NASA Astrophysics Data System (ADS)

    Almarashi, M. M.

    2018-04-01

    We study the signal rates of the second lightest CP-even Higgs boson, h2, of the NMSSM produced in gluon fusion, in association with bottom quarks and in association with top quarks, which is not the SM-like Higgs boson, at the LHC. We evaluate the production rates of h2 in the SM fermionic and bosonic final states in addition to a1a1, h1h1 and Za1 final states. It is observed that the size of the signal rates in some regions of the NMSSM parameter space is quite large and that could help extracting h2 signals at the LHC through a variety of decay channels.

  17. Non-Uniform Sampling and J-UNIO Automation for Efficient Protein NMR Structure Determination.

    PubMed

    Didenko, Tatiana; Proudfoot, Andrew; Dutta, Samit Kumar; Serrano, Pedro; Wüthrich, Kurt

    2015-08-24

    High-resolution structure determination of small proteins in solution is one of the big assets of NMR spectroscopy in structural biology. Improvements in the efficiency of NMR structure determination by advances in NMR experiments and automation of data handling therefore attracts continued interest. Here, non-uniform sampling (NUS) of 3D heteronuclear-resolved [(1)H,(1)H]-NOESY data yielded two- to three-fold savings of instrument time for structure determinations of soluble proteins. With the 152-residue protein NP_372339.1 from Staphylococcus aureus and the 71-residue protein NP_346341.1 from Streptococcus pneumonia we show that high-quality structures can be obtained with NUS NMR data, which are equally well amenable to robust automated analysis as the corresponding uniformly sampled data. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. New one-pot synthesis of spiro[furo[2,3-d]pyrimidine-6,5'-pyrimidine]pentaones and their sulfur analogues.

    PubMed

    Jalilzadeh, Mohammad; Noroozi Pesyan, Nader; Rezaee, Fereshteh; Rastgar, Saeed; Hosseini, Yaser; Sahin, Ertan

    2011-08-01

    Reaction of barbituric acid (BA), 1,3-dimethyl barbituric acid (DMBA) and 2-thiobarbituric acid (TBA) with cyanogen bromide and various aldehydes in presence of triethylamine afforded a new class of heterocyclic stable 5-alkyl and/or 5-aryl-1H, 1'H-spiro[furo[2,3-d]pyrimidine-6,5'-pyrimidine]2,2',4,4',6'(3H,3'H,5H)-pentaones which are dimeric forms of barbiturate (uracil and thiouracil derivatives) at 0 °C to ambient temperatures. Structure elucidation is proved by X-ray crystallography, (1)H NMR, (13)C NMR, FT-IR, CHN and mass analyses techniques. Mechanisms of the formations are discussed.

  19. Hybrid organic-inorganic porous semiconductor transducer for multi-parameters sensing.

    PubMed

    Caliò, Alessandro; Cassinese, Antonio; Casalino, Maurizio; Rea, Ilaria; Barra, Mario; Chiarella, Fabio; De Stefano, Luca

    2015-07-06

    Porous silicon (PSi) non-symmetric multi-layers are modified by organic molecular beam deposition of an organic semiconductor, namely the N,N'-1H,1H-perfluorobutyldicyanoperylene-carboxydi-imide (PDIF-CN2). Joule evaporation of PDIF-CN2 into the PSi sponge-like matrix not only improves but also adds transducing skills, making this solid-state device a dual signal sensor for chemical monitoring. PDIF-CN2 modified PSi optical microcavities show an increase of about five orders of magnitude in electric current with respect to the same bare device. This feature can be used to sense volatile substances. PDIF-CN2 also improves chemical resistance of PSi against alkaline and acid corrosion. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  20. Metal-organic framework superhydrophobic coating on Kevlar fabric with efficient drag reduction and wear resistance

    NASA Astrophysics Data System (ADS)

    Li, Deke; Guo, Zhiguang

    2018-06-01

    Superhydrophobic layers are extremely essential for protecting material surface in various applications. In this study, a stable superhydrophobic mixed matrix surface with a 152.2° contact angle can be fabricated through the technology of layer-by-layer hot-pressing (HoP), and then modified by 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES) on the ZIF-8@Kevlar fabric surface. The morphology and chemical composition were analyzed by the means of SEM, XRD and FTIR. The obtained superhydrophobic coatings showed excellent antiwear performance and drag reduction under desired working conditions. Moreover, we successfully applied superhydrophobic F-ZIF-8@Kevlar fabric in the alcohol adsorbent with high removal capacity, and it can be reused for several times without serious efficiency loss.

  1. Buoyancy increase and drag-reduction through a simple superhydrophobic coating.

    PubMed

    Hwang, Gi Byoung; Patir, Adnan; Page, Kristopher; Lu, Yao; Allan, Elaine; Parkin, Ivan P

    2017-06-08

    A superhydrophobic paint was fabricated using 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES), TiO 2 nanoparticles and ethanol. The paint has potential for aquatic application of a superhydrophobic coating as it induces increased buoyancy and drag reduction. Buoyance testing showed that the reduction of surface energy by superhydrophobic coating made it feasible that glass, a high density material, was supported by the surface tension of water. In a miniature boat sailing test, it was shown that the low energy surface treatment decreased the adhesion of water molecules to the surface of the boat resulting in a reduction of the drag force. Additionally, a robust superhydrophobic surface was fabricated through layer-by-layer coating using adhesive double side tape and the paint, and after a 100 cm abrasion test with sand paper, the surface still retained its water repellency, enhanced buoyancy and drag reduction.

  2. Formation of grafted surface layers on silicon dioxide particles and their investigation by means of thermoprogrammed oxidation

    NASA Astrophysics Data System (ADS)

    Aleksandrova, E. O.; Novichkov, R. V.; Olenin, A. Yu.; Zuev, B. K.

    2017-03-01

    Silica nanoparticles are obtained according to the Stober-Fink-Bohn method, and their surfaces are chemically modified with 1H,1H,2H,2H-perfluorodecyltriethoxysilane. It is estimated that sols of porous silica nanoparticles (average sizes, 50-200 nm) form during primary chemical process; the average size of the particles can be increased to 400-500 nm by consecutive growth. Oxythermography (thermoprogrammed oxidation) measurements reveal a stepped dependence between the content of organic substance of nanoparticles and the duration of chemical modification reaction exists. It is concluded that this could be due to the formation of dense shell (or shells) as a result of sols aging between the cycles of growth; such shells impose diffusive restrictions when molecules penetrate into the pores of the internal volume of the particles.

  3. Extending the Lifetime of Perovskite Solar Cells using a Perfluorinated Dopant.

    PubMed

    Salado, Manuel; Ramos, F Javier; Manzanares, Valentin M; Gao, Peng; Nazeeruddin, Mohammad Khaja; Dyson, Paul J; Ahmad, Shahzada

    2016-09-22

    The principle limitation of perovskite solar cells is related to their instability and, hence, their limited lifetime. Herein, we employ an imidazolium iodide dopant, 1-methyl-3-(1H,1H,2H,2H-nonafluorohexyl)-imidazolium iodide, containing a perfluorous appendage, which leads to prolonged (unencapsulated, under Ar atmosphere) device activities exceeding 100 days without compromising the power conversion efficiency and other photovoltaic parameters. The extended lifetime of the device can be attributed, at least in part, to the hydrophobic nature of the imidazolium iodide salt. The functionalization of the perovskite material was found to have negligible influence on the perovskite crystal structure. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Preparation of superhydrophobic coatings on zinc as effective corrosion barriers.

    PubMed

    Liu, Hongqin; Szunerits, Sabine; Xu, Wenguo; Boukherroub, Rabah

    2009-06-01

    Stable superhydrophobic films with a contact angle of 151 +/- 2 degrees were prepared on zinc substrates by a simple immersion technique into a methanol solution of hydrolyzed 1H,1H,2H,2H-perfluorooctyltrichlorosilane [CF3(CF2)5(CH2)2SiCl3, PFTS] for 5 days at room temperature followed by a short annealing at 130 degrees C in air for 1 h. The superhydrophobic film provides an effective corrosion-resistant coating for the zinc interface when immersed in an aqueous solution of sodium chloride (3% NaCl) for up to 29 days. The corrosion process was investigated by following the change of the water contact angle over time and by electrochemical means. The results are compared to those of unprotected zinc interfaces.

  5. Biosynthetic studies on the botcinolide skeleton: new hydroxylated lactones from Botrytis cinerea.

    PubMed

    Reino, José L; Durán-Patrón, Rosa M; Daoubi, Mourad; Collado, Isidro G; Hernández-Galán, Rosario

    2006-01-20

    [reaction: see text] The biosynthetic origin of the botcinolide skeleton was investigated by means of feeding 13C- and 2H-labeled precursors to Botrytis cinerea. Three new compounds, two homobotcinolide derivatives, 3-O-acetylhomobotcinolide (5) and 8-methylhomobotcinolide (6), and a new 11-membered lactone (7), were isolated. Their structures were elucidated on the basis of spectroscopic data, including one-bond and long-range 1H-13C correlations. The relative stereochemistries were determined by combined analyses of NOE data and 1H-1H coupling constants. According to the results of feeding experiments with 13C- and 2H-labeled acetate and l-S-methylmethionine, 5 is an acetate-derived polyketide whose methyl groups originate from l-S-methylmethionine. This is a rare example of the incorporation of a methyl from methionine into a supposed C3 starter unit of the polyketide synthesis.

  6. High mobility n-type organic thin-film transistors deposited at room temperature by supersonic molecular beam deposition

    SciTech Connect

    Chiarella, F., E-mail: fabio.chiarella@spin.cnr.it; Barra, M.; Ciccullo, F.

    In this paper, we report on the fabrication of N,N′-1H,1H-perfluorobutil dicyanoperylenediimide (PDIF-CN{sub 2}) organic thin-film transistors by Supersonic Molecular Beam Deposition. The devices exhibit mobility up to 0.2 cm{sup 2}/V s even if the substrate is kept at room temperature during the organic film growth, exceeding by three orders of magnitude the electrical performance of those grown at the same temperature by conventional Organic Molecular Beam Deposition. The possibility to get high-mobility n-type transistors avoiding thermal treatments during or after the deposition could significantly extend the number of substrates suitable to the fabrication of flexible high-performance complementary circuits by using this compound.

  7. Impact of surface wettability on S-layer recrystallization: a real-time characterization by QCM-D.

    PubMed

    Iturri, Jagoba; Vianna, Ana C; Moreno-Cencerrado, Alberto; Pum, Dietmar; Sleytr, Uwe B; Toca-Herrera, José Luis

    2017-01-01

    Quartz crystal microbalance with dissipation monitoring (QCM-D) has been employed to study the assembly and recrystallization kinetics of isolated SbpA bacterial surface proteins onto silicon dioxide substrates of different surface wettability. Surface modification by UV/ozone oxidation or by vapor deposition of 1 H ,1 H ,2 H ,2 H -perfluorododecyltrichlorosilane yielded hydrophilic or hydrophobic samples, respectively. Time evolution of frequency and dissipation factors, either individually or combined as the so-called Df plots, showed a much faster formation of crystalline coatings for hydrophobic samples, characterized by a phase-transition peak at around the 70% of the total mass adsorbed. This behavior has been proven to mimic, both in terms of kinetics and film assembly steps, the recrystallization taking place on an underlying secondary cell-wall polymer (SCWP) as found in bacteria. Complementary atomic force microscopy (AFM) experiments corroborate these findings and reveal the impact on the final structure achieved.

  8. Hybrid organic–inorganic porous semiconductor transducer for multi-parameters sensing

    PubMed Central

    Caliò, Alessandro; Cassinese, Antonio; Casalino, Maurizio; Rea, Ilaria; Barra, Mario; Chiarella, Fabio; De Stefano, Luca

    2015-01-01

    Porous silicon (PSi) non-symmetric multi-layers are modified by organic molecular beam deposition of an organic semiconductor, namely the N,N′-1H,1H-perfluorobutyldicyanoperylene-carboxydi-imide (PDIF-CN2). Joule evaporation of PDIF-CN2 into the PSi sponge-like matrix not only improves but also adds transducing skills, making this solid-state device a dual signal sensor for chemical monitoring. PDIF-CN2 modified PSi optical microcavities show an increase of about five orders of magnitude in electric current with respect to the same bare device. This feature can be used to sense volatile substances. PDIF-CN2 also improves chemical resistance of PSi against alkaline and acid corrosion. PMID:26063814

  9. Structure of the Mesophases Formed by a Perfluoroalkyl/Biphenyl Compound. Amphiphilic and Steric Effects

    NASA Astrophysics Data System (ADS)

    Pensec, Sandrine; Tournilhac, François-Genès; Bassoul, Pierre

    1996-11-01

    We describe the synthesis and mesomorphic behaviour of 4-(1H,1H-perfluorooctyloxy)- 4'-methoxy biphenyl. Two mesophases of smectic E and smectic A types were observed. X-ray diffraction study of the smectic E phase indicates a herringbone arrangement of the biphenyl cores, the perfluoroalkyl chains being in a molten state. The {S_E to S_A} transition is related to the melting of the biphenyl sublattice. In both phases, the flexibility of perfluoroalkyl chains permits the area matching between the two segregated sublayers. Nous décrivons la synthèse et les propriétés mésomorphes du 4-(1H,1H-perfluorooctyloxy)- 4'-méthoxy biphényle. Ce composé forme deux mésophases de type smectique E et smectique A. L'analyse par diffraction des rayons X révèle, dans le cas de la phase smectique E un arrangement en chevrons des coeurs biphényles, les chaînes perfluoroalkyles se trouvant dans un état désordonné. La transition {S_E to S_A} correspond à la fusion partielle de la sous-couche biphényle. Dans les deux phases smectiques, la flexibilité des chaînes perfluoroalkyles permet l'adéquation des aires moléculaires entre les deux sous-couches ségrégées.

  10. Association between FASN gene polymorphisms ultrasound carcass traits and intramuscular fat in Qinchuan cattle.

    PubMed

    Raza, Sayed Haidar Abbas; Gui, Linsheng; Khan, Rajwali; Schreurs, Nicola M; Xiaoyu, Wang; Wu, Sen; Mei, Chugang; Wang, Li; Ma, Xueyao; Wei, Dawei; Guo, Hongfang; Zhang, Song; Wang, Xingping; Kaleri, Hubdar Ali; Zan, Linsen

    2018-03-01

    Fatty acid synthase (FASN) is an enzyme involved with fat deposition and fatty acid composition in cattle. This study was conducted to detect single nucleotide polymorphisms (SNPs) of the FASN gene and explore their relationships with ultrasound carcass traits in order to assess the potential use of the FASN gene for the breeding selection of Qinchuan cattle for desirable carcass traits. The frequencies of SNP g.12740C>T, g.13192T>C and g.13232C>T were identified in 525 individual Qinchuan cattle which were also assessed for backfat depth, eye muscle area and intramuscular fat by ultrasound. According to the PIC values, g.13192T>C possessed an intermediate polymorphism (0.25T, g.12740C>T possessed low polymorphism (PIC<0.25). Chi-square tests showed that g.13192T>C were in Hardy-Weinberg disequilibrium (c21 H 1 , H 1 H 4 and H 1 H 2 (P<0.01). The TT genotype at g.13192T>C was associated with a greater eye muscle area and the TT genotype at g.13232C>T was associated with greater intramuscular fat. When these genotypes were combined there was no difference in eye muscle area and intramuscular fat between the diplotypes. The H 2 H 2 diplotype was associated with carcass traits that are likely to provide economic advantage in Qinchuan cattle. Variations in the FASN genes and their corresponding genotypes may be considered as molecular markers for economic traits in cattle breeding. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. NMR polarization echoes in a nematic liquid crystal

    NASA Astrophysics Data System (ADS)

    Levstein, Patricia R.; Chattah, Ana K.; Pastawski, Horacio M.; Raya, Jésus; Hirschinger, Jérôme

    2004-10-01

    We have modified the polarization echo (PE) sequence through the incorporation of Lee-Goldburg cross polarization steps to quench the 1H-1H dipolar dynamics. In this way, the 13C becomes an ideal local probe to inject and detect polarization in the proton system. This improvement made possible the observation of the local polarization P00(t) and polarization echoes in the interphenyl proton of the liquid crystal N-(4-methoxybenzylidene)-4-butylaniline. The decay of P00(t) was well fitted to an exponential law with a characteristic time τC≈310 μs. The hierarchy of the intramolecular dipolar couplings determines a dynamical bottleneck that justifies the use of the Fermi Golden Rule to obtain a spectral density consistent with the structural parameters. The time evolution of P00(t) was reversed by the PE sequence generating echoes at the time expected by the scaling of the dipolar Hamiltonian. This indicates that the reversible 1H-1H dipolar interaction is the main contribution to the local polarization decrease and that the exponential decay for P00(t) does not imply irreversibility. The attenuation of the echoes follows a Gaussian law with a characteristic time τφ≈527 μs. The shape and magnitude of the characteristic time of the PE decay suggest that it is dominated by the unperturbed homonuclear dipolar Hamiltonian. This means that τφ is an intrinsic property of the dipolar coupled network and not of other degrees of freedom. In this case, one cannot unambiguously identify the mechanism that produces the decoherence of the dipolar order. This is because even weak interactions are able to break the fragile multiple coherences originated on the dipolar evolution, hindering its reversal. Other schemes to investigate these underlying mechanisms are proposed.

  12. Study of Perfluorophosphonic Acid Surface Modifications on Zinc Oxide Nanoparticles.

    PubMed

    Quiñones, Rosalynn; Shoup, Deben; Behnke, Grayce; Peck, Cynthia; Agarwal, Sushant; Gupta, Rakesh K; Fagan, Jonathan W; Mueller, Karl T; Iuliucci, Robbie J; Wang, Qiang

    2017-11-28

    In this study, perfluorinated phosphonic acid modifications were utilized to modify zinc oxide (ZnO) nanoparticles because they create a more stable surface due to the electronegativity of the perfluoro head group. Specifically, 12-pentafluorophenoxydodecylphosphonic acid, 2,3,4,5,6-pentafluorobenzylphosphonic acid, and (1H,1H,2H,2H-perfluorododecyl)phosphonic acid have been used to form thin films on the nanoparticle surfaces. The modified nanoparticles were then characterized using infrared spectroscopy, X-ray photoelectron spectroscopy, and solid-state nuclear magnetic resonance spectroscopy. Dynamic light scattering and scanning electron microscopy-energy dispersive X-ray spectroscopy were utilized to determine the particle size of the nanoparticles before and after modification, and to analyze the film coverage on the ZnO surfaces, respectively. Zeta potential measurements were obtained to determine the stability of the ZnO nanoparticles. It was shown that the surface charge increased as the alkyl chain length increases. This study shows that modifying the ZnO nanoparticles with perfluorinated groups increases the stability of the phosphonic acids adsorbed on the surfaces. Thermogravimetric analysis was used to distinguish between chemically and physically bound films on the modified nanoparticles. The higher weight loss for 12-pentafluorophenoxydodecylphosphonic acid and (1H,1H,2H,2H-perfluorododecyl)phosphonic acid modifications corresponds to a higher surface concentration of the modifications, and, ideally, higher surface coverage. While previous studies have shown how phosphonic acids interact with the surfaces of ZnO, the aim of this study was to understand how the perfluorinated groups can tune the surface properties of the nanoparticles.

  13. Fluorination of silicone rubber by plasma polymerization

    NASA Astrophysics Data System (ADS)

    Fielding, Jennifer Chase

    Plasma polymerized fluorocarbon (PPFC) films were deposited onto various silicone rubber substrates, including O-rings, to decrease oil uptake. Depositions were performed using a radio frequency (rf)-powered plasma reactor and various fluorocarbon monomers, such as C2F6, C2F 5H, C3F6, and 1H,1H,2H-perfluoro-1-dodecene. PPFC films which were most promising for inhibiting oil uptake were deposited with 1H,1H,2H-perfluoro-1-dodecene, and were composed predominantly of perfluoromethylene (CF2) species. These films displayed low critical surface energies (as low as 2.7 mJ/m2), and high contact angles with oil (84°), which were correlated with the amount of CF2 species present in the film. For the films with the highest degree of CF2 (up to 67%), CF2 chains may have been oriented slightly perpendicular to the substrate and terminated by CF3 species. Adhesion of the PPFC films directly to silicone rubber was found to be poor. However, when a plasma polymerized hydrocarbon interlayer was deposited on the silicone rubber prior to the fluorocarbon films, adhesion was excellent. O-rings coated with multilayer fluorocarbon films showed 2.6% oil uptake after soaking in oil for 100 hrs at 100°C. Due to variability in data, and the low quality of the industrial grade silicone rubber, the oil uptake mechanism was determined to be from oil flowing through flaws in the film due to defects within the substrate, not from generalized diffusion through the film. This mechanism was confirmed using higher quality silicone rubber, which showed little or no oil diffusion. Therefore, this film may perform well as an oil-repelling barrier when deposited on a high quality silicone rubber.

  14. Association between platelet P2Y12 haplotype and risk of cardiovascular events in chronic coronary disease.

    PubMed

    Schettert, Isolmar T; Pereira, Alexandre C; Lopes, Neuza H; Hueb, Whady A; Krieger, Jose E

    2006-01-01

    A positive association was recently described between P2Y12 platelet receptor H1 and H2 haplotypes and peripheral artery disease. We tested the described P2Y12 receptor haplotypes in a group of patients with coronary artery disease. The P2Y12 platelet receptor H1 and H2 haplotypes was tested in a group of 540 patients enrolled in the Medical, Angioplasty, or Surgery Study II (MASS II), a randomized trial comparing treatments for patients with coronary artery disease (CAD) and preserved left ventricular function. After a 3-year follow-up period, the incidence of the composite end point of cardiac death, myocardial infarction, and refractory angina requiring revascularization was determined in the H1/H1, H1/H2 and H2/H2 haplotype groups. We used Student's t-test and the chi-square test to analyze the differences among groups and Kaplan-Meier method to calculate survival curves. Risk was assessed with the use of a Cox proportional-hazards model. The frequency of haplotypes among studied patients were 410 (75.9%) H1/H1, 119 (22.0%) H1/H2 and 11 (2.1%) H2/H2. The baseline clinical characteristics, mean clinical follow-up time and received treatment of each genotype group were similar. We did not disclose any association between haplotype groups regarding the incidence of any of the studied cardiovascular end-points. This is the first report studying the association of P2Y12 platelet receptor H1 and H2 haplotype and cardiovascular events. Our findings do not provide evidence for a strong association between H1/H1 and H1/H2 haplotypes and a increased risk of cardiovascular events in a population with CAD. Future works should address the role of the H2/H2 haplotype as a genetic marker for cardiovascular events.

  15. Minimizing the t1-noise when using an indirect 1H high-resolution detection of unlabeled samples.

    PubMed

    Shen, M; Wegner, S; Trébosc, J; Hu, B; Lafon, O; Amoureux, J P

    2017-10-01

    The most utilized through-space correlation 1 H-{X} methods with proton indirect detection use two consecutive transfers, 1 H → X and then X →  1 H, with the evolution time t 1 in the middle. When the X isotope is not 100% naturally abundant (NA), only the signal of the protons close to these isotopes is modulated by the 1 H-X dipolar interactions. This signal is theoretically disentangled with phase-cycling from the un-modulated one. However, this separation is never perfect and it may lead to t 1 -noise in case of isotopes with very small NA, such as 13 C or even worse 15 N. One way to reduce this t 1 -noise is to minimize, 'purge', during t 1 the un-modulated 1 H magnetization before trying to suppress it with phase-cycling. We analyze experimentally several sequences following the HORROR condition, which allow purging the 1 H transverse magnetization. The comparison is made at three spinning speeds, including very fast ones for 1 H resolution: 27.75, 55.5 and 111 kHz. We show (i) that the efficiency of this purging process increases with the spinning speed, and (ii) that the best recoupling sequences are the two simplest ones: XY and S 1  = SR2 1 2 . We then compare the S/N that can be achieved with the two most used 1 H-{X} 2D methods, called D-HMQC and CP-CP. The only difference in between these two methods is that the transfers are done with either two π/2-pulses on X channel (D-HMQC), or two Cross-Polarization (CP) transfers (CP-CP). The first method, D-HMQC, is very robust and should be preferred when indirectly detecting nuclei with high NA. The second method, CP-CP, (i) requires experimental precautions to limit the t 1 -noise, and (ii) is difficult to use with quadrupolar nuclei because the two CP transfers are then not efficient nor robust. However, CP-CP is presently the best method to indirectly detect isotopes with small NA, such as 13 C and 15 N. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. A self optimizing synthetic organic reactor system using real-time in-line NMR spectroscopy.

    PubMed

    Sans, Victor; Porwol, Luzian; Dragone, Vincenza; Cronin, Leroy

    2015-02-01

    A configurable platform for synthetic chemistry incorporating an in-line benchtop NMR that is capable of monitoring and controlling organic reactions in real-time is presented. The platform is controlled via a modular LabView software control system for the hardware, NMR, data analysis and feedback optimization. Using this platform we report the real-time advanced structural characterization of reaction mixtures, including 19 F, 13 C, DEPT, 2D NMR spectroscopy (COSY, HSQC and 19 F-COSY) for the first time. Finally, the potential of this technique is demonstrated through the optimization of a catalytic organic reaction in real-time, showing its applicability to self-optimizing systems using criteria such as stereoselectivity, multi-nuclear measurements or 2D correlations.

  17. Utilization of SABRE-derived hyperpolarization to detect low-concentration analytes via 1D and 2D NMR methods.

    PubMed

    Lloyd, Lyrelle S; Adams, Ralph W; Bernstein, Michael; Coombes, Steven; Duckett, Simon B; Green, Gary G R; Lewis, Richard J; Mewis, Ryan E; Sleigh, Christopher J

    2012-08-08

    The characterization of materials by the inherently insensitive method of NMR spectroscopy plays a vital role in chemistry. Increasingly, hyperpolarization is being used to address the sensitivity limitation. Here, by reference to quinoline, we illustrate that the SABRE hyperpolarization technique, which uses para-hydrogen as the source of polarization, enables the rapid completion of a range of NMR measurements. These include the collection of (13)C, (13)C{(1)H}, and NOE data in addition to more complex 2D COSY, ultrafast 2D COSY and 2D HMBC spectra. The observations are made possible by the use of a flow probe and external sample preparation cell to re-hyperpolarize the substrate between transients, allowing repeat measurements to be made within seconds. The potential benefit of the combination of SABRE and 2D NMR methods for rapid characterization of low-concentration analytes is therefore established.

  18. Composite pulsed field gradients with refocused chemical shifts and short recovery time.

    PubMed

    Hu, H; Shaka, A J

    1999-01-01

    An improved self-compensating pulsed field gradient (PFG) technique that combines antiphase gradient pairs with broadband frequency-modulated 180 degrees pulses is proposed. The antiphase gradient pairs lead to superb system recovery. In addition, evolution under chemical shift and heteronuclear J coupling are refocused during the PFG, making it appear effectively instantaneous. This new approach makes it possible to obtain high-resolution phase-sensitive 2D spectra for the PFG version of many experiments such as COSY, DQF-COSY, and HSQC without adding extra compensating delays or pulses. While reasonable suppression of unwanted magnetization is achieved, this method also gives satisfactory retention of desired signals. As a bonus, the field-frequency lock is not perturbed during the experiments. Copyright 1999 Academic Press.

  19. Dropping In a Microgravity Environment (DIME) Contest

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Pictured are students from COSI Academy, Columbus, Ohio and their teacher. The other team was from Sycamore High School in Cincinnati, Ohio. This image is from a digital still camera; higher resolution is not available.

  20. Large reversible magnetostrictive effect of MnCoSi-based compounds prepared by high-magnetic-field solidification

    NASA Astrophysics Data System (ADS)

    Hu, Q. B.; Hu, Y.; Zhang, S.; Tang, W.; He, X. J.; Li, Z.; Cao, Q. Q.; Wang, D. H.; Du, Y. W.

    2018-01-01

    The MnCoSi compound is a potential magnetostriction material since the magnetic field can drive a metamagnetic transition from an antiferromagnetic phase to a high magnetization phase in it, which accompanies a large lattice distortion. However, a large driving magnetic field, magnetic hysteresis, and poor mechanical properties seriously hinder its application for magnetostriction. By substituting Fe for Mn and introducing vacancies of the Mn element, textured and dense Mn0.97Fe0.03CoSi and Mn0.88CoSi compounds are prepared through a high-magnetic-field solidification approach. As a result, large room-temperature and reversible magnetostriction effects are observed in these compounds at a low magnetic field. The origin of this large magnetostriction effect and potential applications are discussed.

  1. Lifetime of heavy hypernuclei and its implications on the weak ΛN interaction

    NASA Astrophysics Data System (ADS)

    Cassing, W.; Jarczyk, L.; Kamys, B.; Kulessa, P.; Ohm, H.; Pysz, K.; Rudy, Z.; Schult, O. W. B.; Ströher, H.

    The lifetime of the Λ-hyperon in heavy hypernuclei measured in proton-Au, -Bi and -U collisions by the COSY-13 Collaboration at COSY-Jülich has been analyzed to yield τΛ = (145+/-11) ps. This value for τΛ is compatible with the lifetime extracted from antiproton annihilation on Bi and U targets, albeit much more accurate. Theoretical models based on the meson exchange picture and assuming the validity of the phenomenological ΔI = 1/2 rule predict the lifetime of heavy hypernuclei to be significantly larger (2-3 standard deviations). Such large differences indicate that at least one of the assumptions in these models is not fulfilled. A much better reproduction of the lifetimes of heavy hypernuclei is achieved in the phase space model, if the ΔI = 1/2 rule is discarded in the nonmesonic Λ decay.

  2. Microgravity

    NASA Image and Video Library

    2001-04-26

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Pictured are students from COSI Academy, Columbus, Ohio and their teacher. The other team was from Sycamore High School in Cincinnati, Ohio. This image is from a digital still camera; higher resolution is not available.

  3. Microgravity

    NASA Image and Video Library

    2001-04-26

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Students from Sycamore High School in Cincinnati, Ohio (girls), and the COSI Academy, Columbus, Ohio (boys), participated. This image is from a digital still camera; higher resolution is not available.

  4. A self optimizing synthetic organic reactor system using real-time in-line NMR spectroscopy† †Electronic supplementary information (ESI) available: Details about the methodology, LabView scripts, experimental set-ups, additional spectra and self-optimization can be found in the SI. See DOI: 10.1039/c4sc03075c Click here for additional data file.

    PubMed Central

    Sans, Victor; Porwol, Luzian; Dragone, Vincenza

    2015-01-01

    A configurable platform for synthetic chemistry incorporating an in-line benchtop NMR that is capable of monitoring and controlling organic reactions in real-time is presented. The platform is controlled via a modular LabView software control system for the hardware, NMR, data analysis and feedback optimization. Using this platform we report the real-time advanced structural characterization of reaction mixtures, including 19F, 13C, DEPT, 2D NMR spectroscopy (COSY, HSQC and 19F-COSY) for the first time. Finally, the potential of this technique is demonstrated through the optimization of a catalytic organic reaction in real-time, showing its applicability to self-optimizing systems using criteria such as stereoselectivity, multi-nuclear measurements or 2D correlations. PMID:29560211

  5. A helical scintillating fiber hodoscope

    NASA Astrophysics Data System (ADS)

    Altmeier, M.; Bauer, F.; Bisplinghoff, J.; Bissel, T.; Bollmann, R.; Busch, M.; Büßer, K.; Colberg, T.; Demirörs, L.; Diehl, O.; Dohrmann, F.; Engelhardt, H. P.; Eversheim, P. D.; Felden, O.; Gebel, R.; Glende, M.; Greiff, J.; Groß, A.; Groß-Hardt, R.; Hinterberger, F.; Jahn, R.; Jeske, M.; Jonas, E.; Krause, H.; Lahr, U.; Langkau, R.; Lindemann, T.; Lindlein, J.; Maier, R.; Maschuw, R.; Mayer-Kuckuck, T.; Meinerzhagen, A.; Nähle, O.; Pfuff, M.; Prasuhn, D.; Rohdjeß, H.; Rosendaal, D.; von Rossen, P.; Sanz, B.; Schirm, N.; Schulz-Rojahn, M.; Schwarz, V.; Scobel, W.; Thomas, S.; Trelle, H. J.; Weise, E.; Wellinghausen, A.; Wiedmann, W.; Woller, K.; Ziegler, R.; EDDA Collaboration

    1999-07-01

    A novel scintillating fiber hodoscope in helically cylindric geometry has been developed for detection of low multiplicity events of fast protons and other light charged particles in the internal target experiment EDDA at the Cooler Synchrotron COSY. The hodoscope consists of 640 scintillating fibers (2.5 mm diameter), arranged in four layers surrounding the COSY beam pipe. The fibers are helically wound in opposing directions and read out individually using 16-channel photomultipliers connected to a modified commercial encoding system. The detector covers an angular range of 9°⩽ Θ⩽72° and 0°⩽ ϕ⩽360° in the lab frame. The detector length is 590 mm, the inner diameter 161 mm. Geometry and granularity of the hodoscope afford a position resolution of about 1.3 mm. The detector design took into consideration a maximum of reliability and a minimum of maintenance. An LED array may be used for monitoring purposes.

  6. Controllable surface-plasmon resonance in engineered nanometer epitaxial silicide particles embedded in silicon

    NASA Technical Reports Server (NTRS)

    Fathauer, R. W.; Ksendzov, A.; Iannelli, J. M.; George, T.

    1991-01-01

    Epitaxial CoSi2 particles in a single-crystal silicon matrix are grown by molecular-beam epitaxy using a technique that allows nanometer control over particle size in three dimensions. These composite layers exhibit resonant absorption predicted by effective-medium theory. Selection of the height and diameter of disklike particles through a choice of growth conditions allows tailoring of the depolarization factor and hence of the surface-plasmon resonance energy. Resonant absorption from 0.49 to 1.04 eV (2.5 to 1.2 micron) is demonstrated and shown to agree well with values predicted by the Garnett (1904, 1906) theory using the bulk dielectric constants for CoSi2 and Si.

  7. Growth of single-crystalline cobalt silicide nanowires and their field emission property.

    PubMed

    Lu, Chi-Ming; Hsu, Han-Fu; Lu, Kuo-Chang

    2013-07-03

    In this work, cobalt silicide nanowires were synthesized by chemical vapor deposition processes on Si (100) substrates with anhydrous cobalt chloride (CoCl2) as precursors. Processing parameters, including the temperature of Si (100) substrates, the gas flow rate, and the pressure of reactions were varied and studied; additionally, the physical properties of the cobalt silicide nanowires were measured. It was found that single-crystal CoSi nanowires were grown at 850°C ~ 880°C and at a lower gas flow rate, while single-crystal Co2Si nanowires were grown at 880°C ~ 900°C. The crystal structure and growth direction were identified, and the growth mechanism was proposed as well. This study with field emission measurements demonstrates that CoSi nanowires are attractive choices for future applications in field emitters.

  8. Growth of single-crystalline cobalt silicide nanowires and their field emission property

    PubMed Central

    2013-01-01

    In this work, cobalt silicide nanowires were synthesized by chemical vapor deposition processes on Si (100) substrates with anhydrous cobalt chloride (CoCl2) as precursors. Processing parameters, including the temperature of Si (100) substrates, the gas flow rate, and the pressure of reactions were varied and studied; additionally, the physical properties of the cobalt silicide nanowires were measured. It was found that single-crystal CoSi nanowires were grown at 850°C ~ 880°C and at a lower gas flow rate, while single-crystal Co2Si nanowires were grown at 880°C ~ 900°C. The crystal structure and growth direction were identified, and the growth mechanism was proposed as well. This study with field emission measurements demonstrates that CoSi nanowires are attractive choices for future applications in field emitters. PMID:23819795

  9. Dropping In a Microgravity Environment (DIME) Contest

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The first NASA Dropping In a Microgravity Environment (DIME) student competition pilot project came to a conclusion at the Glenn Research Center in April 2001. The competition involved high-school student teams who developed the concept for a microgravity experiment and prepared an experiment proposal. The two student teams - COSI Academy, sponsored by the Columbus Center of Science and Industry, and another team from Cincinnati, Ohio's Sycamore High School, designed a microgravity experiment, fabricated the experimental apparatus, and visited NASA Glenn to operate their experiment in the 2.2 Second Drop Tower. Students from Sycamore High School in Cincinnati, Ohio (girls), and the COSI Academy, Columbus, Ohio (boys), participated. This image is from a digital still camera; higher resolution is not available.

  10. Spin Dependence of η Meson Production in Proton-Proton Collisions Close to Threshold.

    PubMed

    Adlarson, P; Augustyniak, W; Bardan, W; Bashkanov, M; Bass, S D; Bergmann, F S; Berłowski, M; Bondar, A; Büscher, M; Calén, H; Ciepał, I; Clement, H; Czerwiński, E; Demmich, K; Engels, R; Erven, A; Erven, W; Eyrich, W; Fedorets, P; Föhl, K; Fransson, K; Goldenbaum, F; Goswami, A; Grigoryev, K; Gullström, C-O; Heijkenskjöld, L; Hejny, V; Hüsken, N; Jarczyk, L; Johansson, T; Kamys, B; Kemmerling, G; Khatri, G; Khoukaz, A; Khreptak, O; Kirillov, D A; Kistryn, S; Kleines, H; Kłos, B; Krzemień, W; Kulessa, P; Kupść, A; Kuzmin, A; Lalwani, K; Lersch, D; Lorentz, B; Magiera, A; Maier, R; Marciniewski, P; Mariański, B; Morsch, H-P; Moskal, P; Ohm, H; Parol, W; Perez Del Rio, E; Piskunov, N M; Prasuhn, D; Pszczel, D; Pysz, K; Pyszniak, A; Ritman, J; Roy, A; Rudy, Z; Rundel, O; Sawant, S; Schadmand, S; Schätti-Ozerianska, I; Sefzick, T; Serdyuk, V; Shwartz, B; Sitterberg, K; Skorodko, T; Skurzok, M; Smyrski, J; Sopov, V; Stassen, R; Stepaniak, J; Stephan, E; Sterzenbach, G; Stockhorst, H; Ströher, H; Szczurek, A; Trzciński, A; Wolke, M; Wrońska, A; Wüstner, P; Yamamoto, A; Zabierowski, J; Zieliński, M J; Złomańczuk, J; Żuprański, P; Żurek, M

    2018-01-12

    Taking advantage of the high acceptance and axial symmetry of the WASA-at-COSY detector, and the high polarization degree of the proton beam of COSY, the reaction p[over →]p→ppη has been measured close to threshold to explore the analyzing power A_{y}. The angular distribution of A_{y} is determined with the precision improved by more than 1 order of magnitude with respect to previous results, allowing a first accurate comparison with theoretical predictions. The determined analyzing power is consistent with zero for an excess energy of Q=15  MeV, signaling s-wave production with no evidence for higher partial waves. At Q=72  MeV the data reveal strong interference of Ps and Pp partial waves and cancellation of (Pp)^{2} and Ss^{*}Sd contributions. These results rule out the presently available theoretical predictions for the production mechanism of the η meson.

  11. Symposium Q: Magnetic Thin Films, Heterostructures, and Device Materials

    DTIC Science & Technology

    2007-05-22

    results in the formation of sodium carboxylate groups, that electronics, also known as magnetoelectronics or spintronics. Mn promoted the adsorption of...Q8.29 Magnetic Properties of Microcrystalline Si Thin films and Nickel Silicide Nanowires. Joondong Kim’, Seongjin Jang 2 , Bi-Ching Shih 2 , Hao...Buffalo, New York. The silicides , such as NiSi 2 and CoSi2 , have been attractive materials to crystallize Si and grow an epitaxial Si film with a small

  12. A sulphated flavone glycoside from Livistona australis and its antioxidant and cytotoxic activity.

    PubMed

    Kassem, Mona E S; Shoela, Soha; Marzouk, Mona M; Sleem, Amany A

    2012-01-01

    A new flavone glycoside tricin 7-O-β-glucopyranoside-2″-sulphate sodium salt along with 14 known flavonoid compounds were isolated and identified from the aqueous methanol extract of Livistona australis leaves. Their structures were established on the basis of extensive NMR (¹H, ¹³C, HSQC and H-H COSY) and ESIMS data. Antioxidant and cytotoxicity properties of the methanol extract of the leaves as well as the new compound were investigated.

  13. A bis-bithiophene from Tridax procumbens L. (Asteraceae).

    PubMed

    Ali, Muhammad Shaiq; Jahangir, Muhammad

    2002-08-01

    The ethyl acetate soluble part of hexane extract of Tridax procumbens yielded a new bis-bithiophene named tridbisbithiophene along with four known terpenoids: taraxasteryl acetate, beta-amyrenone, lupeol and oleanolic acid, which have never been reported so far from Tridax procumbens. The structures of all the isolated constituents were elucidated with the aid of 1D-NMR spectroscopy whereas, the structure of new constituent tridbisbithiophene was confirmed via COSY and HMBC interactions.

  14. Chromaticity calculations and code comparisons for x-ray lithography source XLS and SXLS rings

    SciTech Connect

    Parsa, Z.

    1988-06-16

    This note presents the chromaticity calculations and code comparison results for the (x-ray lithography source) XLS (Chasman Green, XUV Cosy lattice) and (2 magnet 4T) SXLS lattices, with the standard beam optic codes, including programs SYNCH88.5, MAD6, PATRICIA88.4, PATPET88.2, DIMAD, BETA, and MARYLIE. This analysis is a part of our ongoing accelerator physics code studies. 4 figs., 10 tabs.

  15. Dynamics of Hyperon Production

    NASA Astrophysics Data System (ADS)

    Sibirtsev, A.

    2007-11-01

    The progress of strangeness physics at COSY in both experimental and theoretical aspects is reviewed. It is argued that the dynamics of hyperon production involves excitation of baryons and that it is feasible to study their properties such as mass and total width. It is shown that under certain kinematical cuts the resonance signal can be isolated from the effect due to the final state interaction. Recent puzzles concerning the Σ-hyperon production are discussed.

  16. Studies of Silicon-Refractory Metal Interfaces: Photoemission Study of Interface Formation and Compound Nucleation.

    DTIC Science & Technology

    1984-10-29

    Photoelectron energy analysis was done with Si s states 10--14 eV below E,. For CoSi2 and NiSi2, a commercial double-pass electron energy analyzer . The...Collaborative studies with theorists gave rise to modeling ,f interfaces and calculation of electronic energy states for ordered silicides. (i, ,I... analyzed by a double-pass cylindrical mirror energy A. There is no evidence of Cr outdiffusion into the Au analyzer , and the overall resolution

  17. Project Work Assignment | Sustainable Stormwater Funding Project

    EPA Pesticide Factsheets

    2010-11-30

    ... J'l.wroprl 8OOljJf!'l fOI 8..... n """ Nwo I.1n DCN N. e_ e_ prog~;"':x~~ment ObI~~Cl~·· unt I ICents) SI:~~~O:t COSI~~od. Max6 Mo•• Ma:t6 ,,",7 1 ...

  18. Bioactive steroidal sulfates from the ambulakrums of the Pacific starfish Lysastrosoma anthosticta.

    PubMed

    Levina, Eleonora V; Kalinovsky, Anatoly I; Dmitrenok, Pavel S; Aminin, Dmitry L

    2009-08-01

    Lysaketotriol (1) and lysaketodiol (2), along with two previously known polyhydroxylated steroidal sulfates (3, 4), were isolated from the ethanolic extract of ambulakrums separated from the arms of the starfish Lysastrosoma anthosticta (Sea of Japan). The chemical structures have been elucidated using 1D and 2D NMR spectroscopy (1H, 13C, DEPT, COSY-45, HSQC and HMBC) and mass spectrometry. Compound 1 produced moderate stimulation of lysosomal activity in mouse splenocytes and compounds 1-2 showed immunomodulatory activity.

  19. DIME Students Waiting for Their Turn to Drop Experiment

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Students pause while waiting their turn at the 2.2-second Drop Tower during the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  20. DIME Participants Prepare Experiment Rig

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Students prepare their experiment apparatus for free-fall during the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  1. DIME Students Share Comments About Experiments

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Students discuss fine points of their final design for the drop tower experiment during the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  2. DIME Fluid Payload on Student Platform

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Colored oil flow toy was part of a student-designed apparatus used in the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  3. Student-Designed Fluid Experiment for DIME Competition

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Student-designed and -built apparatus for the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  4. DIME Participant Preparing Experiment Rig

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Students prepare to load fluids in their experiment apparatus during the Dropping In a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  5. DIME Students Discuss Final Drop Tower Experiment Design

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Students discuss fine points of their final design for the Drop Tower experiment during the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  6. DIME Students Preparing Their Experiment

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Students prepare to load fluids in their experiment apparatus during the Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  7. Resveratrol tetramer of hopeaphenol isolated from Shorea johorensis (Dipterocarpaceae)

    SciTech Connect

    Aisha, Farra; Din, Laily B.; Yaacob, W. A.

    2014-09-03

    Hopeaphenol (1) as a resveratrol tetramer was isolated from the bark of Shorea johorensis collected from Imbak Canyon, Sabah, Malaysia. The structure of this compound was determined by the spectroscopic evidences using {sup 1}H- and {sup 13}C-NMR assigned with HSQC, HMBC, {sup 1}H−{sup 1}H COSY and {sup 1}H−{sup 1}H NOESY spectra, mass spectrum, and by comparison with reported data.

  8. New sesquiterpenes from Euonymus europaeus (Celastraceae).

    PubMed

    Descoins, Charles; Bazzocchi, Isabel López; Ravelo, Angel Gutiérrez

    2002-02-01

    A new sesquiterpene evoninate alkaloid (1), and two sesquiterpenes (2, 3) with a dihydro-beta-agarofuran skeleton, along with three known sesquiterpenes (4-6), were isolated from the seeds of Euonymus europaeus. Their structures were elucidated by high resolution mass analysis, and one- and two-dimensional (1D and 2D) NMR spectroscopy, including homonuclear and heteronuclear correlation [correlation spectroscopy (COSY), rotating frame Overhauser enhancement spectroscopy (ROESY), heteronuclear single quantum coherence (HSQC), and heteronuclear multiple bond correlation (HMBC)] experiments.

  9. A new lignan glycoside from the rhizomes of Imperata cylindrica.

    PubMed

    Lee, Dae-Young; Han, Kyung-Min; Song, Myoung-Chong; Lee, Do-Gyeong; Rho, Yeong-Deok; Baek, Nam-In

    2008-01-01

    A new lignan glycoside, 6-acetyl-1-[1,3-(4,4'-dihydroxy-3,3'-dimethoxy-beta-truxinyl)-beta-d-fructofuranosyl]-alpha-d-glucopyranoside (1), named impecyloside, was isolated from the rhizomes of Imperata cylindrica. The structure of the compound was determined by spectroscopic data including FABMS, UV, IR, 1H NMR and 13C NMR (DEPT) and 2D NMR (COSY, HSQC, HMBC).

  10. A Novel Multi-voxel Based Quantitation of Metabolites and Lipids Non-invasively Combined with Diffusion Weighted Imaging in Breast Cancer

    DTIC Science & Technology

    2011-09-01

    SATURATED AND UNSATURATED LIPIDS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON... saturated fatty acid, mono- unsaturated and poly unsaturated fatty acids. 6 Figure 3. Prior-knowledge COSY spectra for the breast metabolites (top...In addition to water, presence of 2D diagonal and cross peaks from the methyl, methylene, and olefenic protons of unsaturated and saturated 8

  11. Fluid Physics

    NASA Image and Video Library

    2002-08-07

    Colored oil flow toy was part of a student-designed apparatus used in the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  12. Ultrahigh-Resolution Magnetic Resonance in Inhomogeneous Magnetic Fields: Two-Dimensional Long-Lived-Coherence Correlation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Chinthalapalli, Srinivas; Bornet, Aurélien; Segawa, Takuya F.; Sarkar, Riddhiman; Jannin, Sami; Bodenhausen, Geoffrey

    2012-07-01

    A half-century quest for improving resolution in Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) has enabled the study of molecular structures, biological interactions, and fine details of anatomy. This progress largely relied on the advent of sophisticated superconducting magnets that can provide stable and homogeneous fields with temporal and spatial variations below ΔB0/B0<0.01ppm. In many cases however, inherent properties of the objects under investigation, pulsating arteries, breathing lungs, tissue-air interfaces, surgical implants, etc., lead to fluctuations and losses of local homogeneity. A new method dubbed “long-lived-coherence correlation spectroscopy” (LLC-COSY) opens the way to overcome both inhomogeneous and homogeneous broadening, which arise from local variations in static fields and fluctuating dipole-dipole interactions, respectively. LLC-COSY makes it possible to obtain ultrahigh resolution two-dimensional spectra, with linewidths on the order of Δν=0.1 to 1 Hz, even in very inhomogeneous fields (ΔB0/B0>10ppm or 5000 Hz at 9.7 T), and can improve resolution by a factor up to 9 when the homogeneous linewidths are determined by dipole-dipole interactions. The resulting LLC-COSY spectra display chemical shift differences and scalar couplings in two orthogonal dimensions, like in “J spectroscopy.” LLC-COSY does not require any sophisticated gradient switching or frequency-modulated pulses. Applications to in-cell NMR and to magnetic resonance spectroscopy (MRS) of selected volume elements in MRI appear promising, particularly when susceptibility variations tend to preclude high resolution.

  13. How to Reach a Thousand-Second in-Plane Polarization Lifetime with 0.97 - GeV / c Deuterons in a Storage Ring

    DOE PAGES

    Guidoboni, G.; Stephenson, E.; Andrianov, S.; ...

    2016-07-28

    Here, we observe a deuteron beam polarization lifetime near 1000 s in the horizontal plane of a magnetic storage ring (COSY). This long spin coherence time is maintained through a combination of beam bunching, electron cooling, sextupole field corrections, and the suppression of collective effects through beam current limits. This record lifetime is required for a storage ring search for an intrinsic electric dipole moment on the deuteron at a statistical sensitivity level approaching 10 -29 $e$ cm.

  14. Mapping of the surface rupture induced by the M 7.3 Kumamoto Earthquake along the Eastern segment of Futagawa fault using image correlation techniques

    NASA Astrophysics Data System (ADS)

    Ekhtari, N.; Glennie, C. L.; Fielding, E. J.; Liang, C.

    2016-12-01

    Near field surface deformation is vital to understanding the shallow fault physics of earthquakes but near-field deformation measurements are often sparse or not reliable. In this study, we use the Co-seismic Image Correlation (COSI-Corr) technique to map the near-field surface deformation caused by the M 7.3 April 16, 2016 Kumamoto Earthquake, Kyushu, Japan. The surface rupture around the Eastern segment of Futagawa fault is mapped using a pair of panchromatic 1.5 meter resolution SPOT 7 images. These images were acquired on January 16 and April 29, 2016 (3 months before and 13 days after the earthquake respectively) with close to nadir (less than 1.5 degree off nadir) viewing angle. The two images are ortho-rectified using SRTM Digital Elevation Model and further co-registered using tie points far away from the rupture field. Then the COSI-Corr technique is utilized to produce an estimated surface displacement map, and a horizontal displacement vector field is calculated which supplies a seamless estimate of near field displacement measurements along the Eastern segment of the Futagawa fault. The COSI-Corr estimated displacements are then compared to other existing displacement observations from InSAR, GPS and field observations.

  15. Ultralow 1/f Noise in a Heterostructure of Superconducting Epitaxial Cobalt Disilicide Thin Film on Silicon.

    PubMed

    Chiu, Shao-Pin; Yeh, Sheng-Shiuan; Chiou, Chien-Jyun; Chou, Yi-Chia; Lin, Juhn-Jong; Tsuei, Chang-Chyi

    2017-01-24

    High-precision resistance noise measurements indicate that the epitaxial CoSi 2 /Si heterostructures at 150 and 2 K (slightly above its superconducting transition temperature T c of 1.54 K) exhibit an unusually low 1/f noise level in the frequency range of 0.008-0.2 Hz. This corresponds to an upper limit of Hooge constant γ ≤ 3 × 10 -6 , about 100 times lower than that of single-crystalline aluminum films on SiO 2 capped Si substrates. Supported by high-resolution cross-sectional transmission electron microscopy studies, our analysis reveals that the 1/f noise is dominated by excess interfacial Si atoms and their dimer reconstruction induced fluctuators. Unbonded orbitals (i.e., dangling bonds) on excess Si atoms are intrinsically rare at the epitaxial CoSi 2 /Si(100) interface, giving limited trapping-detrapping centers for localized charges. With its excellent normal-state properties, CoSi 2 has been used in silicon-based integrated circuits for decades. The intrinsically low noise properties discovered in this work could be utilized for developing quiet qubits and scalable superconducting circuits for future quantum computing.

  16. Thermoelectric properties of Si/CoSi2 sub-micrometer composites prepared by melt-spinning technique

    NASA Astrophysics Data System (ADS)

    Xie, Jun; Ohishi, Yuji; Ichikawa, Satoshi; Muta, Hiroaki; Kurosaki, Ken; Yamanaka, Shinsuke

    2017-05-01

    We here report on the influence of CoSi2 precipitates on the thermoelectric properties of heavily doped p-type Si. A simple self-assembly process using a melt-spinning technique followed by spark plasma sintering is introduced to prepare bulk Si/CoSi2 composites with a nominal composition of (Si0.99B0.01)95Co5. Scanning and transmission electron microscopy observations present clear evidence of a sub-micrometer CoSi2 phase with a size ranging from 50 to 500 nm. These sub-micrometer precipitates resulted in a retention of the high electrical performance of heavily doped Si, while simultaneously reducing thermal conductivity by over 20% compared to a coarse CoSi2 phase (1-10 μm) in a comparative sample prepared by arc melting and spark plasma sintering. As a result, a figure of merit ZT value of 0.21 at 1073 K was achieved in the sub-micrometer Si/CoSi2, an increase of 16% compared with the ZT value for homogeneous p-type Si with a similar carrier concentration. This suggests that the self-assembled sub-micrometer inclusions effectively enhanced the thermoelectric performance of Si-based thermoelectric materials.

  17. Low-power adiabatic sequences for in-vivo localized two-dimensional chemical shift correlated MR spectroscopy

    PubMed Central

    Andronesi, Ovidiu C.; Ramadan, Saadallah; Mountford, Carolyn E.; Sorensen, A. Gregory

    2011-01-01

    Novel low-power adiabatic sequences are demonstrated for in-vivo localized two-dimensional (2D) correlated MR spectroscopy, such as COSY (Correlated Spectroscopy) and TOCSY (Total Correlated Spectroscopy). The design is based on three new elements for in-vivo 2D MRS: the use of gradient modulated constant adiabaticity GOIA-W(16,4) pulses for i) localization (COSY and TOCSY) and ii) mixing (TOCSY), and iii) the use of longitudinal mixing (z-filter) for magnetization transfer during TOCSY. GOIA-W(16,4) provides accurate signal localization, and more importantly, lowers the SAR for both TOCSY mixing and localization. Longitudinal mixing improves considerably (five-folds) the efficiency of TOCSY transfer. These are markedly different from previous 1D editing TOCSY sequences using spatially non-selective pulses and transverse mixing. Fully adiabatic (adiabatic mixing with adiabatic localization) and semi-adiabatic (adiabatic mixing with non-adiabatic localization) methods for 2D TOCSY are compared. Results are presented for simulations, phantoms, and in-vivo 2D spectra from healthy volunteers and patients with brain tumors obtained on 3T clinical platforms equipped with standard hardware. To the best of our knowledge this is the first demonstration of in-vivo adiabatic 2D TOCSY and fully adiabatic 2D COSY. It is expected that these methodological developments will advance the in-vivo applicability of multi(spectrally)dimensional MRS to reliably identify metabolic biomarkers. PMID:20890988

  18. Cobalt silicide nanocables grown on Co films: synthesis and physical properties.

    PubMed

    Hsin, Cheng-Lun; Yu, Shih-Ying; Wu, Wen-Wei

    2010-12-03

    Single-crystalline cobalt silicide/SiO(x) nanocables have been grown on Co thin films on an SiO(2) layer by a self-catalysis process via vapor-liquid-solid mechanism. The nanocables consist of a core of CoSi nanowires and a silicon oxide shell with a length of several tens of micrometers. In the confined space in the oxide shell, the CoSi phase is stable and free from agglomeration in samples annealed in air ambient at 900 °C for 1 h. The nanocable structure came to a clear conclusion that the thermal stability of the silicide nanowires can be resolved by the shell encapsulation. Cobalt silicide nanowires were obtained from the nanocable structure. The electrical properties of the CoSi nanowires have been found to be compatible with their thin film counterpart and a high maximum current density of the nanowires has been measured. One way to obtain silicate nanowires has been demonstrated. The silicate compound, which is composed of cobalt, silicon and oxygen, was achieved. The Co silicide/oxide nanocables are potentially useful as a key component of silicate nanowires, interconnects and magnetic units in nanoelectronics.

  19. Optimization of homonuclear 2D NMR for fast quantitative analysis: application to tropine-nortropine mixtures.

    PubMed

    Giraudeau, Patrick; Guignard, Nadia; Hillion, Emilie; Baguet, Evelyne; Akoka, Serge

    2007-03-12

    Quantitative analysis by (1)H NMR is often hampered by heavily overlapping signals that may occur for complex mixtures, especially those containing similar compounds. Bidimensional homonuclear NMR spectroscopy can overcome this difficulty. A thorough review of acquisition and post-processing parameters was carried out to obtain accurate and precise, quantitative 2D J-resolved and DQF-COSY spectra in a much reduced time, thus limiting the spectrometer instabilities in the course of time. The number of t(1) increments was reduced as much as possible, and standard deviation was improved by optimization of spectral width, number of transients, phase cycling and apodization function. Localized polynomial baseline corrections were applied to the relevant chemical shift areas. Our method was applied to tropine-nortropine mixtures. Quantitative J-resolved spectra were obtained in less than 3 min and quantitative DQF-COSY spectra in 12 min, with an accuracy of 3% for J-spectroscopy and 2% for DQF-COSY, and a standard deviation smaller than 1%.

  20. The Compton Spectrometer and Imager: Results from the 2016 Super-Pressure Balloon Campaign

    NASA Astrophysics Data System (ADS)

    Lowell, Alexander; Boggs, Steven; Chiu, Jeng-Lun; Kierans, Carolyn; Sleator, Clio; Tomsick, John; Zoglauer, Andreas; Amman, Mark; Chang, Hsiang-Kuang; Tseng, Chao-Hsiung; Yang, Chien-Ying; Lin, Chih H.; Jean, Pierre; von Ballmoos, Peter

    2017-08-01

    The Compton Spectrometer and Imager is a 0.2-5 MeV Compton telescope capable of imaging, spectroscopy and polarimetry of astrophysical sources. Such capabilities are made possible by COSI's twelve germanium cross-strip detectors, which provide for high efficiency, high resolution spectroscopy, and precise 3D positioning of photon interactions. In May 2016, COSI took flight from Wanaka, New Zealand on a NASA super-pressure balloon. For 46 days, COSI floated at a nominal altitude of 33.5 km, continually telemetering science data in real-time. The payload made a safe landing in Peru, and the hard drives containing the full raw data set were recovered. Analysis efforts have resulted in detections of various sources such as the Crab Nebula, Cyg X-1, Cen A, Galactic Center e+e- annihilation, and the long duration gamma-ray burst GRB 160530A. In this presentation, I will provide an overview of our main results, which include measuring the polarization of GRB 160530A, and our image of the Galactic Center at 511 keV. Additionally, I will summarize results pertaining to our detections of the Crab Nebula, Cyg X-1, and Cen A.

  1. Fast experiments for structure elucidation of small molecules: Hadamard NMR with multiple receivers.

    PubMed

    Gierth, Peter; Codina, Anna; Schumann, Frank; Kovacs, Helena; Kupče, Ēriks

    2015-11-01

    We propose several significant improvements to the PANSY (Parallel NMR SpectroscopY) experiments-PANSY COSY and PANSY-TOCSY. The improved versions of these experiments provide sufficient spectral information for structure elucidation of small organic molecules from just two 2D experiments. The PANSY-TOCSY-Q experiment has been modified to allow for simultaneous acquisition of three different types of NMR spectra-1D C-13 of non-protonated carbon sites, 2D TOCSY and multiplicity edited 2D HETCOR. In addition the J-filtered 2D PANSY-gCOSY experiment records a 2D HH gCOSY spectrum in parallel with a (1) J-filtered HC long-range HETCOR spectrum as well as offers a simplified data processing. In addition to parallel acquisition, further time savings are feasible because of significantly smaller F1 spectral windows as compared to the indirect detection experiments. Use of cryoprobes and multiple receivers can significantly alleviate the sensitivity issues that are usually associated with the so called direct detection experiments. In cases where experiments are sampling limited rather than sensitivity limited further reduction of experiment time is achieved by using Hadamard encoding. In favorable cases the total recording time for the two PANSY experiments can be reduced to just 40 s. The proposed PANSY experiments provide sufficient information to allow the CMCse software package (Bruker) to solve structures of small organic molecules. Copyright © 2015 John Wiley & Sons, Ltd.

  2. BI- and tricyclic diterpenoids from Halimium viscosum.

    PubMed

    Rodilla, J M; De Mendonça, D I; Ismael, M I; Figueiredo, J A; Silva, M L; Lopes, E

    2001-01-01

    The study of the acid and neutral parts of the n-hexane extract of Halimium viscosum (S. João da Pesqueira, Portugal) has led to the isolation of various known diterpenoids with the ent-halimane skeleton. Five new compounds have now been isolated, one with the ent-halimane skeleton, and four with the valparane skeleton, two of them with the valparane skeleton degraded. The structures of these compounds, determined by spectroscopic methods using 2D experiments (1H-13C, HMQC and HMBC), were dimethyl 1(10)-halimen-15,18-dioate, dimethyl 3,19-dinor-15-valparen-2,4-dioate, methyl 16-nor-2,3-secovalpara-3,15-dioxo-2-oate, 1,3,5,1 5-valparatetraene and 3R-4alpha-methoxy-15-valparen-2-one.

  3. Application of ex situ dynamic nuclear polarization in studying small molecules.

    PubMed

    Ludwig, Christian; Marin-Montesinos, Ildefonso; Saunders, Martin G; Emwas, Abdul-Hamid; Pikramenou, Zoe; Hammond, Stephen P; Günther, Ulrich L

    2010-06-14

    Dynamic nuclear polarization (DNP) has become an attractive technique to boost the sensitivity of NMR experiments. In the case of ex situ polarizations two-dimensional (2D) spectra are limited by the short lifetime of the polarization after dissolution and sample transfer to a high field NMR magnet. This limitation can be overcome by various approaches. Here we show how the use of (13)C-labelled acetyl tags can help to obtain 2D-HMQC spectra for many small molecules, owing to a nuclear Overhauser enhancement between (13)C spins originating from the long-lived carbonyl carbon, which extends the lifetimes of other (13)C spins with shorter longitudinal relaxation times. We also show an alternative approach of using an optimized polarization matrix.

  4. Low-density lipoprotein (LDL)-antioxidant biflavonoids from Garcinia madruno.

    PubMed

    Osorio, Edison; Londoño, Julián; Bastida, Jaume

    2013-05-22

    Six biflavonoids were isolated from G. madruno, one of which, 7''-O-(6''''-acetyl)-glucoside of morelloflavone, is a new compound identified on the basis of 1D, 2D NMR (HMQC and HMBC) spectroscopic methods and chemical evidence. The antioxidant activity of the biflavonoids against low-density lipoprotein (LDL) peroxidation induced with Cu²⁺, was studied by means of a TBARS assay. The antioxidant potential of a biflavonoid fraction (BF) was also evaluated and correlated with its biflavonoid content. The flavanone-(3→8'')-flavone biflavonoids displayed antioxidant activity, particularly morelloflavone, which was significantly more potent than quercetin, with a CE₅₀ of 12.36 μg/mL. Lipid peroxidation, was also significantly reduced in the presence of the BF (EC₅₀ = 11.85 μg/mL). These results suggest that the BF is an excellent antioxidant.

  5. Flavonoids from the stems of Croton caudatus Geisel. var. tomentosus Hook.

    PubMed

    Zou, Guo-An; Su, Zhi-Heng; Zhang, Hong-Wu; Wang, Yuan; Yang, Jun-Shan; Zou, Zhong-Mei

    2010-02-26

    A new flavone, named crotoncaudatin (1), was isolated from the stems of Croton caudatus Geisel. var. tomentosus Hook., together with nine known analogues: 3,5,6,7,8,3',4'-heptamethoxyflavone (2), tangeretin (3), nobiletin (4), 5,6,7,4'-tetramethoxy-flavone (5), sinensetin (6), kaempferol (7), tiliroside (8), kaempferol-3-O-rutinoside (9) and rutin (10). The structures of the above compounds were established by a combination of spectroscopic methods, including HR-ESI-MS, 1H-NMR, 13C-NMR, HMQC and HMBC spectra. All compounds were isolated from and identified in this species for the first time and compounds 1-6 are new for the genus Croton.

  6. Dammarane-type triterpenes from the Brazilian medicinal plant Cordia multispicata.

    PubMed

    Kuroyanagi, Masanori; Kawahara, Nobuo; Sekita, Setsuko; Satake, Motoyoshi; Hayashi, Tatsuo; Takase, Yoichi; Masuda, Kazuo

    2003-10-01

    From the Brazilian medicinal plant Carucaá (Cordia multispicata), oleanane- and ursane-type triterpenoids were previously reported as anti-androgenic constituents of the plant. In this study, purification of the polar elements of the EtOAc-soluble fraction of the plant revealed nine novel dammarane-type triterpenes, named cordianols A-I (1-9) along with the known compound cordialin A (10). The structures of these new compounds were elucidated by means of spectral methods including HRFABMS, (1)H NMR, (13)C NMR, and 2D NMR (HMQC, HMBC, NOESY). Absolute configuration at C-23 of compound 7 was determined by an excitone chirality method. Some of these new compounds revealed a hemiketal structure on the A ring and a hydroxylated or epoxidated 20(22)-(E)-ene side chain and showed weak anti-androgenic activity.

  7. Chemical synthesis of beta-O-4 type artificial lignin.

    PubMed

    Kishimoto, Takao; Uraki, Yasumitsu; Ubukata, Makoto

    2006-04-07

    An artificial lignin polymer containing only the beta-O-4 substructure was synthesized. The procedure consists of two key steps: 1) polycondensation of a brominated monomer by aromatic Williamson reaction; and 2) subsequent reduction of the carbonyl polymer. 13C-NMR and HMQC spectra of the polymer were consistent with beta-O-4 substructures in milled wood lignin isolated from Japanese fir wood. The weight average degree of polymerization (DP(w)) ranged from 19.5 to 30.6, which is comparable to enzymatically synthesized artificial lignin from p-hydroxycinnamyl alcohols (dehydrogenation polymer, DHP) and some isolated lignins. Using this new lignin model polymer, it will now be possible to reinvestigate the properties and reactivity of the main lignin structure in terms of its polymeric character.

  8. Dual allosteric activation mechanisms in monomeric human glucokinase

    PubMed Central

    Whittington, A. Carl; Larion, Mioara; Bowler, Joseph M.; Ramsey, Kristen M.; Brüschweiler, Rafael; Miller, Brian G.

    2015-01-01

    Cooperativity in human glucokinase (GCK), the body’s primary glucose sensor and a major determinant of glucose homeostatic diseases, is fundamentally different from textbook models of allostery because GCK is monomeric and contains only one glucose-binding site. Prior work has demonstrated that millisecond timescale order-disorder transitions within the enzyme’s small domain govern cooperativity. Here, using limited proteolysis, we map the site of disorder in unliganded GCK to a 30-residue active-site loop that closes upon glucose binding. Positional randomization of the loop, coupled with genetic selection in a glucokinase-deficient bacterium, uncovers a hyperactive GCK variant with substantially reduced cooperativity. Biochemical and structural analysis of this loop variant and GCK variants associated with hyperinsulinemic hypoglycemia reveal two distinct mechanisms of enzyme activation. In α-type activation, glucose affinity is increased, the proteolytic susceptibility of the active site loop is suppressed and the 1H-13C heteronuclear multiple quantum coherence (HMQC) spectrum of 13C-Ile–labeled enzyme resembles the glucose-bound state. In β-type activation, glucose affinity is largely unchanged, proteolytic susceptibility of the loop is enhanced, and the 1H-13C HMQC spectrum reveals no perturbation in ensemble structure. Leveraging both activation mechanisms, we engineer a fully noncooperative GCK variant, whose functional properties are indistinguishable from other hexokinase isozymes, and which displays a 100-fold increase in catalytic efficiency over wild-type GCK. This work elucidates specific structural features responsible for generating allostery in a monomeric enzyme and suggests a general strategy for engineering cooperativity into proteins that lack the structural framework typical of traditional allosteric systems. PMID:26283387

  9. Dual allosteric activation mechanisms in monomeric human glucokinase.

    PubMed

    Whittington, A Carl; Larion, Mioara; Bowler, Joseph M; Ramsey, Kristen M; Brüschweiler, Rafael; Miller, Brian G

    2015-09-15

    Cooperativity in human glucokinase (GCK), the body's primary glucose sensor and a major determinant of glucose homeostatic diseases, is fundamentally different from textbook models of allostery because GCK is monomeric and contains only one glucose-binding site. Prior work has demonstrated that millisecond timescale order-disorder transitions within the enzyme's small domain govern cooperativity. Here, using limited proteolysis, we map the site of disorder in unliganded GCK to a 30-residue active-site loop that closes upon glucose binding. Positional randomization of the loop, coupled with genetic selection in a glucokinase-deficient bacterium, uncovers a hyperactive GCK variant with substantially reduced cooperativity. Biochemical and structural analysis of this loop variant and GCK variants associated with hyperinsulinemic hypoglycemia reveal two distinct mechanisms of enzyme activation. In α-type activation, glucose affinity is increased, the proteolytic susceptibility of the active site loop is suppressed and the (1)H-(13)C heteronuclear multiple quantum coherence (HMQC) spectrum of (13)C-Ile-labeled enzyme resembles the glucose-bound state. In β-type activation, glucose affinity is largely unchanged, proteolytic susceptibility of the loop is enhanced, and the (1)H-(13)C HMQC spectrum reveals no perturbation in ensemble structure. Leveraging both activation mechanisms, we engineer a fully noncooperative GCK variant, whose functional properties are indistinguishable from other hexokinase isozymes, and which displays a 100-fold increase in catalytic efficiency over wild-type GCK. This work elucidates specific structural features responsible for generating allostery in a monomeric enzyme and suggests a general strategy for engineering cooperativity into proteins that lack the structural framework typical of traditional allosteric systems.

  10. Fast Magic-Angle Spinning Three-Dimensional NMR Experiment for Simultaneously Probing H-H and N-H Proximities in Solids.

    PubMed

    Reddy, G N Manjunatha; Malon, Michal; Marsh, Andrew; Nishiyama, Yusuke; Brown, Steven P

    2016-12-06

    A fast magic-angle spinning (MAS, 70 kHz) solid-state NMR experiment is presented that combines 1 H Double-Quantum (DQ) and 14 N- 1 H HMQC (Heteronuclear Multiple-Quantum Coherence) pulse-sequence elements, so as to simultaneously probe H-H and N-H proximities in molecular solids. The proposed experiment can be employed in both two-dimensional (2D) and three-dimensional (3D) versions: first, a 2D 14 N HMQC-filtered 1 H-DQ experiment provides specific DQ-SQ correlation peaks for proton pairs that are in close proximities to the nitrogen sites, thereby achieving spectral filtration. Second, a proton-detected three-dimensional (3D) 1 H(DQ)- 14 N(SQ)- 1 H(SQ) experiment correlates 1 H(DQ)- 1 H(SQ) chemical shifts with 14 N shifts such that longer range N···H-H correlations are observed between protons and nitrogen atoms with internuclear NH distances exceeding 3 Å. Both 2D and 3D versions of the proposed experiment are demonstrated for an amino acid hydrochloride salt, l-histidine·HCl·H 2 O, and a DNA nucleoside, guanosine·2H 2 O. In the latter case, the achieved spectral filtration ensures that DQ cross peaks are only observed for guanine NH and CH8 1 H resonances and not ribose and water 1 H resonances, thus providing insight into the changes in the solid-state structure of this hydrate that occur over time; significant changes are observed in the NH and NH 2 1 H chemical shifts as compared to the freshly recrystallized sample previously studied by Reddy et al., Cryst. Growth Des. 2015, 15, 5945.

  11. Development of solid-state NMR techniques for the characterisation of pharmaceutical compounds

    NASA Astrophysics Data System (ADS)

    Tatton, Andrew S.

    Structural characterisation in the solid state is an important step in understanding the physical and chemical properties of a material. Solid-state NMR techniques applied to solid delivery forms are presented as an alternative to more established structural characterisation methods. The effect of homonuclear decoupling upon heteronuclear couplings is investigated using a combination of experimental and density-matrix simulation results acquired from a 13C-1H spinecho pulse sequence, modulated by scalar couplings. It is found that third-order cross terms under MAS and homonuclear decoupling contribute to strong dephasing effects in the NMR signal. Density-matrix simulations allow access to parameters currently unattainable in experiment, and demonstrate that higher homonuclear decoupling rf nutation frequencies reduce the magnitude of third-order cross terms. 15N-1H spinecho experiments were applied to pharmaceutically relevant samples to differentiate between the number of directly attached protons. Using this method, proton transfer in an acid-base reaction is proven in pharmaceutical salts. The indirect detection of 14N lineshapes via protons obtained using 2D 14N-1H HMQC experiments is presented, where coherence transfer is achieved via heteronuclear through-space dipolar couplings. The importance of fast MAS frequencies is demonstrated, and it is found that increasing the recoupling duration reveals longer range NH proximities. The 2D 14N-1H HMQC method is used to demonstrate the presence of specific hydrogen bonding interactions, and thus aid in identifying molecular association in a cocrystal and an amorphous dispersion. In addition, hydrogen bonding motifs were identified by observing the changes in the 14N quadrupolar parameters between individual molecular components relative to the respective solid delivery form. First-principles calculations of NMR chemical shifts and quadrupolar parameters using the GIPAW method were combined with 14N-1H experimental

  12. H(C)P and H(P)C triple-resonance experiments at natural abundance employing long-range couplings.

    PubMed

    Malon, Michal; Koshino, Hiroyuki

    2007-09-01

    Modified two-dimensional (2D) triple-resonance H(C)P and H(P)C experiments based on INEPT/HMQC and double-INEPT schemes are applied to the study of organophosphorus compounds at natural abundances. The implementation of effective (1)H--(13)C gradient selection, additional purging pulsed field gradients, spinlock pulses, and improved phase cycling is demonstrated to allow weak correlation signals based on long-range couplings to be readily observed. Through the combination of two heteronuclear long-range coupling constants, (n)J(CH) and (n)J(PC) in H(C)P experiments or (n)J(PH) and (n)J(PC) in H(P)C experiments, protons can be correlated to a second heteronucleus through 4-7 chemical bonds. These experiments thus overcome the inherit limitations of classical (1)H-X HMBC experiments, which require a nonzero value of the heteronuclear coupling constant (n)J(XH). Ultra-broadband inversion composite pulses are successfully employed in the H(P)C INEPT/HMQC and H(P)C double-INEPT pulse sequences to increase the utility of the experiments and the quality of obtained spectra. This work extends and completes a set of 2D phase-sensitive triple-resonance experiments applicable at natural abundances, and also offers insight into the methodology of triple-resonance experiments and the application of pulsed field gradients. A one-dimensional triple-resonance experiment employing carbon detection is suggested for accurate determination of small (n)J(PC).

  13. 3D DOSY-TROSY to determine the translational diffusion coefficient of large protein complexes.

    PubMed

    Didenko, Tatiana; Boelens, Rolf; Rüdiger, Stefan G D

    2011-01-01

    The translational diffusion coefficient is a sensitive parameter to probe conformational changes in proteins and protein-protein interactions. Pulsed-field gradient NMR spectroscopy allows one to measure the translational diffusion with high accuracy. Two-dimensional (2D) heteronuclear NMR spectroscopy combined with diffusion-ordered spectroscopy (DOSY) provides improved resolution and therefore selectivity when compared with a conventional 1D readout. Here, we show that a combination of selective isotope labelling, 2D ¹H-¹³C methyl-TROSY (transverse relaxation-optimised spectroscopy) and DOSY allows one to study diffusion properties of large protein complexes. We propose that a 3D DOSY-heteronuclear multiple quantum coherence (HMQC) pulse sequence, that uses the TROSY effect of the HMQC sequence for ¹³C methyl-labelled proteins, is highly suitable for measuring the diffusion coefficient of large proteins. We used the 20 kDa co-chaperone p23 as model system to test this 3D DOSY-TROSY technique under various conditions. We determined the diffusion coefficient of p23 in viscous solutions, mimicking large complexes of up to 200 kDa. We found the experimental data to be in excellent agreement with theoretical predictions. To demonstrate the use for complex formation, we applied this technique to record the formation of a complex of p23 with the molecular chaperone Hsp90, which is around 200 kDa. We anticipate that 3D DOSY-TROSY will be a useful tool to study conformational changes in large protein complexes.

  14. A simplified characterization of S-adenosyl-l-methionine-consuming enzymes with 1-Step EZ-MTase: a universal and straightforward coupled-assay for in vitro and in vivo setting† †Electronic supplementary information (ESI) available: Experimental materials and methods, characterization of all compounds (1H–1H COSY NMR, 1H–13C edited HSQC NMR, MS analysis), supplementary figures and tables, worksheets for the 1-Step EZ-MTase assay using both UV- and fluorescence-detection mode, a worksheet for the determination of glycine N-methyltransferase activity within biological samples. Samples of purified TM0936 will be distributed upon request. See DOI: 10.1039/c7sc02830j

    PubMed Central

    Walters, Ryan O.; Huffman, Derek M.

    2017-01-01

    Methyltransferases use S-adenosyl-l-methionine (SAM) to deposit methyl marks. Many of these epigenetic ‘writers’ are associated with gene regulation. As cancer etiology is highly correlated with misregulated methylation patterns, methyltransferases are emerging therapeutic targets. Successful assignment of methyltransferases' roles within intricate biological networks relies on (1) the access to enzyme mechanistic insights and (2) the efficient screening of chemical probes against these targets. To characterize methyltransferases in vitro and in vivo, we report a highly-sensitive one-step deaminase-linked continuous assay where the S-adenosyl-l-homocysteine (SAH) enzyme-product is rapidly and quantitatively catabolized to S-inosyl-l-homocysteine (SIH). To highlight the broad capabilities of this assay, we established enzymatic characteristics of two protein arginine methyltransferases (PRMT5 and PRMT7), a histone-lysine N-methyltransferase (DIM-5) and a sarcosine/dimethylglycine N-methyltransferase (SDMT). Since the coupling deaminase TM0936 displays robust activity over a broad pH-range we determined the pH dependence of SDMT reaction rates. TM0936 reactions are monitored at 263 nm, so a drawback may arise when methyl acceptor substrates absorb within this UV-range. To overcome this limitation, we used an isosteric fluorescent SAM-analog: S-8-aza-adenosyl-l-methionine. Most enzymes tolerated this probe and sustained methyltransfers were efficiently monitored through loss of fluorescence at 360 nm. Unlike discontinuous radioactive- and antibody-based assays, our assay provides a simple, versatile and affordable approach towards the characterization of methyltransferases. Supported by three logs of linear dynamic range, the 1-Step EZ-MTase can detect methylation rates as low as 2 μM h–1, thus making it possible to quantify low nanomolar concentrations of glycine N-methyltransferase within crude biological samples. With Z′-factors above 0.75, this assay is well suited to high-throughput screening and may promote the identification of novel therapeutics. PMID:29449933

  15. Fluorination of Boron-Doped Diamond Film Electrodes for Minimization of Perchlorate Formation.

    PubMed

    Gayen, Pralay; Chaplin, Brian P

    2017-08-23

    This research investigated the effects of surface fluorination on both rates of organic compound oxidation (phenol and terephthalic acid (TA)) and ClO 4 - formation at boron-doped diamond (BDD) film anodes at 22 °C. Different fluorination methods (i.e., electrochemical oxidation with perfluorooctanoic acid (PFOA), radio frequency plasma, and silanization) were used to incorporate fluorinated moieties on the BDD surface, which was confirmed by X-ray photoelectron spectroscopy (XPS). The silanization method was found to be the most effective fluorination method using a 1H,1H,2H,2H-perfluorodecyltrichlorosilane precursor to form a self-assembled monolayer (SAM) on the oxygenated BDD surface. The ClO 4 - formation decreased from rates of 0.45 ± 0.03 mmol m -2 min -1 during 1 mM NaClO 3 oxidation and 0.28 ± 0.01 mmol m -2 min -1 during 10 mM NaCl oxidation on the BDD electrode to below detectable levels (<0.12 μmoles m -2 min -1 ) for the BDD electrode functionalized by a 1H,1H,2H,2H-perfluorodecyltrichlorosilane SAM. These decreases in rates corresponded to 99.94 and 99.85% decreases in selectivity for ClO 4 - formation during the electrolysis of 10 mM NaCl and 1 mM NaClO 3 electrolytes, respectively. By contrast, the oxidation rates of phenol were reduced by only 16.3% in the NaCl electrolyte and 61% in a nonreactive 0.1 M KH 2 PO 4 electrolyte. Cyclic voltammetry with Fe(CN) 6 3-/4- and Fe 3+/2+ redox couples indicated that the long fluorinated chains created a blocking layer on the BDD surface that inhibited charge transfer via steric hindrance and hydrophobic effects. The surface coverages and thicknesses of the fluorinated films controlled the charge transfer rates, which was confirmed by estimates of film thicknesses using XPS and density functional theory simulations. The aliphatic silanized electrode also showed very high stability during OH • production. Perchlorate formation rates were below the detection limit (<0.12 μmoles m -2 min -1 ) for up to 10

  16. Control and characterization of textured, hydrophobic ionomer surfaces

    NASA Astrophysics Data System (ADS)

    Wang, Xueyuan

    Polymer thin films are of increasing interest in many industrial and technological applications. Superhydrophobic, self-cleaning surfaces have attracted a lot of attention for their application in self-cleaning, anti-sticking coatings, stain resistance, or anti-contamination surfaces in diverse technologies, including medical, transportation, textiles, electronics and paints. This thesis focuses on the preparation of nanometer to micrometer-size particle textured surfaces which are desirable for super water repellency. Textured surfaces consisting of nanometer to micrometer-sized lightly sulfonated polystyrene ionomer (SPS) particles were prepared by rapid evaporation of the solvent from a dilute polymer solution cast onto silica. The effect of the solvent used to spin coat the film, the molecular weight of the ionomer, and the rate of solvent evaporation were investigated. The nano-particle or micron-particle textured ionomer surfaces were prepared by either spin coating or solution casting ionomer solutions at controlled evaporation rates. The surface morphologies were consistent with a spinodal decomposition mechanism where the surface first existed as a percolated-like structure and then ripened into droplets if molecular mobility was retained for sufficient time. The SPS particles or particle aggregates were robust and resisted deformation even after annealing at 120°C for one week. The water contact angles on as-prepared surfaces were relatively low, ~ 90° since the polar groups in ionomer reduce the surface hydrophobicity. After chemical vapor deposition of 1H,1H,2H,2H-perfluorooctyltrichlorosilane, the surface contact angles increased to ~ 109° on smooth surfaces and ~140° on the textured surfaces. Water droplets stuck to these surfaces even when tilted 90 degrees. Superhydrophobic surfaces were prepared by spraying coating ionomer solutions and Chemical Vapor Deposition (CVD) of 1H,1H,2H,2H-perfluorooctyltrichlorosilane onto textured surfaces. The

  17. The effect of polar end of long-chain fluorocarbon oligomers in promoting the superamphiphobic property over multi-scale rough Al alloy surfaces

    NASA Astrophysics Data System (ADS)

    Saifaldeen, Zubayda S.; Khedir, Khedir R.; Camci, Merve T.; Ucar, Ahmet; Suzer, Sefik; Karabacak, Tansel

    2016-08-01

    Rough structures with re-entrant property and their subsequent surface energy reduction with long-chain fluorocarbon oligomers are both critical in developing superamphiphobic (SAP, i.e. both super hydrophobic and superoleophobic) surfaces. However, morphology of the low-surface energy layer on a rough re-entrant substrate can strongly depend on the fluorocarbon oligomers used. In this study, the effect of polar end of different kinds of long-chain fluorocarbon oligomers in promoting a self-assembled monolayer with close packed molecules and robust adhesion on multi-scale rough Al alloy surfaces was investigated. Hierarchical Al alloy surfaces with microgrooves and nanograss structures were developed by a simple combination of one-directional mechanical sanding and post treatment in boiling de-ionized water (DIW). Three types of long-chain fluorocarbon oligomers of 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (PFDTS), 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane (PFDCS), and perfluorooctanoic acid (PFOA) were chemically vaporized onto these rough Al alloy surfaces. The PFDCS exhibited the lowest surface free energy of less than 10 mN/m. The contact angle and sliding angle measurements for water, ethylene glycol, and peanut oil verified the SAP property of hierarchical rough Al alloy surfaces treated with alkylsilane oligomers (PFDTS, PFDCS). However, the hierarchical surfaces treated with fluorocarbon oligomer with polar acidic tail (PFOA) showed highly amphiphobic properties but could not reach the threshold for SAP. Chemical stability of the hierarchical Al alloy surfaces treated with the fluorocarbon oligomers was tested under the harsh conditions of ultra-sonication in acetone and annealing at high temperature after different treatment times. Contact angle measurements revealed the robustness of the alkylsilane oligomers and deterioration of the PFOA coating particularly for low surface tension liquids. The robust adhesion and close-packing of the alkylsilane

  18. Lack of sleep is associated with internet use for leisure.

    PubMed

    Kim, So Young; Kim, Min-Su; Park, Bumjung; Kim, Jin-Hwan; Choi, Hyo Geun

    2018-01-01

    Previous studies have suggested that excessive internet use may cause lack of sleep. However, recent studies have hypothesized that lack of sleep may instigate internet use for leisure. To elucidate the potential effects of sleep time on internet use, we explored the different associations between sleep time and internet use according to its purpose. The population-based, cross-sectional study group from the Korea Youth Risk Behavior Web-based Survey (KYRBWS) collected data from 57,425 middle school students in 2014 and 2015. Sleep time over the past 7 days was classified into the following groups: < 7 h (6 h); ≥ 7 h, < 8 h (7 h); ≥ 8 h, < 9 h (8 h); and ≥ 9 h (9+ h). Internet use time per day was separately surveyed for leisure and for study and categorized as follows: 0 h; > 0 h, ≤ 1 h (1 h); > 1 h, ≤ 2 h (2 h); and > 2 h (2+ h) per day. Information on age, sex, region of residence, body mass index (BMI), economic level, parental education level, stress level, school performance level, and sleep satisfaction were retrieved. The relationships between sleep time and internet use time for leisure/study were analyzed using multinomial logistic regression with complex sampling. In the subgroup analysis according to sleep satisfaction (good, normal, and poor), the associations of sleep time with internet use for leisure were analyzed using the same methods. Compared to 9+ h of sleep, less sleep was related to a long internet use time (2+ h) for leisure (adjusted odds ratio, AOR [95% confidence interval, CI] of sleep: 8 h = 1.23 [1.14-1.32]; 7 h = 1.42 [1.31-1.54]; and 6 h = 1.56 [1.44-1.70]; P < 0.001). Conversely, a relationship between less sleep and a long internet use time (2+ h) for study was evident only for 6 h of sleep (AOR of sleep: 8 h = 0.84 [0.84-1.04]; 7 h = 1.05 [0.94-1.17]; and 6 h = 1.32 [1.27-1.59]; P < 0.001). In the subgroup analysis according to sleep satisfaction, less sleep was associated with a long internet use time for leisure in all

  19. NMR and mass spectrometric characterization of vinblastine, vincristine and some new related impurities - part I.

    PubMed

    Dubrovay, Zsófia; Háda, Viktor; Béni, Zoltán; Szántay, Csaba

    2013-10-01

    In the course of exploring the possibilities of developing a new, improved process at Gedeon Richter for the production of the "bisindole" alkaloids vinblastine (VLB) and vincristine (VCR), some novel VLB/VCR-related trace impurities were detected by analytical HPLC. Following isolation by preparative HPLC, a combination of 1D and 2D ultra high-field NMR and high-resolution (HR) (LC-)MS/MS studies allowed the structural identification and complete spectral characterization of several hitherto unpublished VLB/VCR-analogue impurities. Since the impurities could not be isolated in entirely pure forms and were available only in minute, mass-limited quantities, accessing the spectral information needed for their ab initio structure determination was met with various practical difficulties. Successful structure determination therefore relied heavily on the availability and use of detailed and definitive spectral data for both VLB and VCR. In particular, the utilization of detailed (1)H, (13)C, and (15)N NMR assignments as well as (1)H-(1)H, (1)H-(13)C and (1)H-(15)N spin-spin connectivities pertaining to different solvents for VLB/VCR base and sulphate salt was required. Although NMR studies on VLB base and other bisindoles were reported earlier in the literature, an NMR characterization of VLB and VCR under the above-mentioned circumstances and using ultra-high field instrumentation is either scarcely available or entirely lacking, therefore the necessary data had to be obtained in-house. Likewise, a modern tandem HR-ESI-MS/MS(n) fragmentation study of VLB and VCR has not been published yet. In the present paper we therefore give a thorough NMR and MS characterization of VLB and VCR specifically with a view to filling this void and to provide sufficiently extensive and solid reference data for the structural investigation of the aforementioned VLB/VCR impurities. Besides being scientifically relevant in its own right, the disclosed data should be useful for anyone

  20. A Bivalent Heterologous DNA Virus-Like-Particle Prime-Boost Vaccine Elicits Broad Protection against both Group 1 and 2 Influenza A Viruses

    PubMed Central

    Jiang, Wenbo; Wang, Shuangshuang; Chen, Honglin; Ren, Huanhuan; Huang, Xun; Wang, Guiqin; Chen, Ling; Chen, Zhiwei

    2017-01-01

    ABSTRACT Current seasonal influenza vaccines are efficacious when vaccine strains are matched with circulating strains. However, they do not protect antigenic variants and newly emerging pandemic and outbreak strains. Thus, there is a critical need for developing so-called “universal” vaccines that protect against all influenza viruses. In the present study, we developed a bivalent heterologous DNA virus-like particle prime-boost vaccine strategy. We show that mice immunized with this vaccine were broadly protected against lethal challenge from group 1 (H1, H5, and H9) and group 2 (H3 and H7) viruses, with 94% aggregate survival. To determine the immune correlates of protection, we performed passive immunizations and in vitro assays. We show that this vaccine elicited antibody responses that bound HA from group 1 (H1, H2, H5, H6, H8, H9, H11, and H12) and group 2 (H3, H4, H7, H10, H14, and H15) and neutralized homologous and intrasubtypic H5 and H7 and heterosubtypic H1 viruses and hemagglutinin-specific CD4 and CD8 T cell responses. As a result, passive immunization with immune sera fully protected mice against H5, H7, and H1 challenge, whereas with both immune sera and T cells the mice survived heterosubtypic H3 and H9 challenge. Thus, it appears that (i) neutralizing antibodies alone fully protect against homologous and intrasubtypic H5 and H7 and (ii) neutralizing and binding antibodies are sufficient to protect against heterosubtypic H1, (iii) but against heterosubtypic H3 and H9, binding antibodies and T cells are required for complete survival. We believe that this vaccine regimen could potentially be a candidate for a “universal” influenza vaccine. IMPORTANCE Influenza virus infection is global health problem. Current seasonal influenza vaccines are efficacious only when vaccine strains are matched with circulating strains. However, these vaccines do not protect antigenic variants and newly emerging pandemic and outbreak strains. Because of this

  1. Proton chemical shift tensors determined by 3D ultrafast MAS double-quantum NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Rongchun; Mroue, Kamal H.; Ramamoorthy, Ayyalusamy

    2015-10-01

    Proton NMR spectroscopy in the solid state has recently attracted much attention owing to the significant enhancement in spectral resolution afforded by the remarkable advances in ultrafast magic angle spinning (MAS) capabilities. In particular, proton chemical shift anisotropy (CSA) has become an important tool for obtaining specific insights into inter/intra-molecular hydrogen bonding. However, even at the highest currently feasible spinning frequencies (110-120 kHz), 1H MAS NMR spectra of rigid solids still suffer from poor resolution and severe peak overlap caused by the strong 1H-1H homonuclear dipolar couplings and narrow 1H chemical shift (CS) ranges, which render it difficult to determine the CSA of specific proton sites in the standard CSA/single-quantum (SQ) chemical shift correlation experiment. Herein, we propose a three-dimensional (3D) 1H double-quantum (DQ) chemical shift/CSA/SQ chemical shift correlation experiment to extract the CS tensors of proton sites whose signals are not well resolved along the single-quantum chemical shift dimension. As extracted from the 3D spectrum, the F1/F3 (DQ/SQ) projection provides valuable information about 1H-1H proximities, which might also reveal the hydrogen-bonding connectivities. In addition, the F2/F3 (CSA/SQ) correlation spectrum, which is similar to the regular 2D CSA/SQ correlation experiment, yields chemical shift anisotropic line shapes at different isotropic chemical shifts. More importantly, since the F2/F1 (CSA/DQ) spectrum correlates the CSA with the DQ signal induced by two neighboring proton sites, the CSA spectrum sliced at a specific DQ chemical shift position contains the CSA information of two neighboring spins indicated by the DQ chemical shift. If these two spins have different CS tensors, both tensors can be extracted by numerical fitting. We believe that this robust and elegant single-channel proton-based 3D experiment provides useful atomistic-level structural and dynamical information for

  2. Defining Coastal Storm and Quantifying Storms Applying Coastal Storm Impulse Parameter

    NASA Astrophysics Data System (ADS)

    Mahmoudpour, Nader

    2014-05-01

    What defines a storm condition and what would initiate a "storm" has not been uniquely defined among scientists and engineers. Parameters that have been used to define a storm condition can be mentioned as wind speed, beach erosion and storm hydrodynamics parameters such as wave height and water levels. Some of the parameters are storm consequential such as beach erosion and some are not directly related to the storm hydrodynamics such as wind speed. For the purpose of the presentation, the different storm conditions based on wave height, water levels, wind speed and beach erosion will be discussed and assessed. However, it sounds more scientifically to have the storm definition based on the hydrodynamic parameters such as wave height, water level and storm duration. Once the storm condition is defined and storm has initiated, the severity of the storm would be a question to forecast and evaluate the hazard and analyze the risk in order to determine the appropriate responses. The correlation of storm damages to the meteorological and hydrodynamics parameters can be defined as a storm scale, storm index or storm parameter and it is needed to simplify the complexity of variation involved developing the scale for risk analysis and response management. A newly introduced Coastal Storm Impulse (COSI) parameter quantifies storms into one number for a specific location and storm event. The COSI parameter is based on the conservation of linear, horizontal momentum to combine storm surge, wave dynamics, and currents over the storm duration. The COSI parameter applies the principle of conservation of momentum to physically combine the hydrodynamic variables per unit width of shoreline. This total momentum is then integrated over the duration of the storm to determine the storm's impulse to the coast. The COSI parameter employs the mean, time-averaged nonlinear (Fourier) wave momentum flux, over the wave period added to the horizontal storm surge momentum above the Mean High

  3. IMRT vs. 3D Noncoplanar Treatment Plans for Maxillary Sinus Tumors: A New Tool for Quantitative Evaluation

    SciTech Connect

    Levin, Daphne; Menhel, Janna; Alezra, Dror

    2008-01-01

    We compared 9-field, equispaced intensity modulated radiation therapy (IMRT), 4- to 5-field, directionally optimized IMRT, and 3-dimensional (3D) noncoplanar planning approaches for tumors of the maxillary sinus. Ten patients were planned retrospectively to compare the different treatment techniques. Prescription doses were 60 to 70 Gy. Critical structures contoured included optic nerves and chiasm, lacrimal glands, lenses, and retinas. As an aid for plan assessment, we introduced a new tool: Critical Organ Scoring Index (COSI), which allows quantitative evaluation of the tradeoffs between target coverage and critical organ sparing. This index was compared with other, commonly used conformity indices. For amore » reliable assessment of both tumor coverage and dose to critical organs in the different planning techniques, we introduced a 2D, graphical representation of COSI vs. conformity index (CI). Dose-volume histograms and mean, maximum, and minimum organ doses were also compared. IMRT plans delivered lower doses to ipsilateral structures, but were unable to spare them. 3D plans delivered less dose to contralateral structures, and were more homogeneous, as well. Both IMRT approaches gave similar results. In cases where choice of optimal plan was difficult, the novel 2D COSI-CI representation gave an accurate picture of the tradeoffs between target coverage and organ sparing, even in cases where other conformity indices failed. Due to their unique anatomy, maxillary sinus tumors may benefit more from a noncoplanar approach than from IMRT. The new graphical representation proposed is a quick, visual, reliable tool, which may facilitate the physician's choice of best treatment plan for a given patient.« less

  4. WHO European Childhood Obesity Surveillance Initiative in Serbia: a prevalence of overweight and obesity among 6-9-year-old school children.

    PubMed

    Djordjic, Visnja; Radisavljevic, Snezana; Milanovic, Ivana; Bozic, Predrag; Grbic, Miljana; Jorga, Jagoda; Ostojic, Sergej M

    2016-09-01

    The World Health Organization (WHO) European Childhood Obesity Surveillance Initiative (COSI) is a public health program established in order to understand the progress of the obesity epidemic in young populations and gain inter-country comparisons within the European region, yet the data from a number of East European countries, including Serbia, were not available then. Therefore, the main aim of this cross-sectional study was to collect data about the prevalence of overweight and obesity among 6-9-year-old school children in Serbia according to the standardized protocol during the Fourth COSI Implementation Round. From September 2015 to November 2015, 5102 first- and second-grade primary-school children (age 7.7±0.6 years) were assessed for weight, height, and body mass index (BMI) in 14 Serbian school districts. The prevalence rates of obesity, as calculated using the International Obesity Task Force (IOTF) cut-off points, vary across different age groups, with the lowest obesity rates reported in 7-year-old boys (6.2%), while the highest obesity prevalence rates were observed in 6-year-old boys (9.7%). In addition, being overweight was strongly associated with poor local community development and lower level of urbanization. The overall prevalence of overweight (23.1%, including obesity) and obesity (6.9%) in Serbian primary-school children seem to be comparable to rather high rates previously reported in other countries participating in the COSI program, indicating an obesity epidemic in Serbian children. This surveillance system should be regularly implemented throughout Europe, providing comparable data on rates of overweight/obesity in primary schools that might drive prudent actions to reverse the pandemic trend of childhood obesity.

  5. WHO European Childhood Obesity Surveillance Initiative: body mass index and level of overweight among 6-9-year-old children from school year 2007/2008 to school year 2009/2010.

    PubMed

    Wijnhoven, Trudy M A; van Raaij, Joop M A; Spinelli, Angela; Starc, Gregor; Hassapidou, Maria; Spiroski, Igor; Rutter, Harry; Martos, Éva; Rito, Ana I; Hovengen, Ragnhild; Pérez-Farinós, Napoleón; Petrauskiene, Ausra; Eldin, Nazih; Braeckevelt, Lien; Pudule, Iveta; Kunešová, Marie; Breda, João

    2014-08-07

    The World Health Organization (WHO) Regional Office for Europe has established the Childhood Obesity Surveillance Initiative (COSI) to monitor changes in overweight in primary-school children. The aims of this paper are to present the anthropometric results of COSI Round 2 (2009/2010) and to explore changes in body mass index (BMI) and overweight among children within and across nine countries from school years 2007/2008 to 2009/2010. Using cross-sectional nationally representative samples of 6-9-year-olds, BMI, anthropometric Z-scores and overweight prevalence were derived from measured weight and height. Significant changes between rounds were assessed using variance and t-tests analyses. At Round 2, the prevalence of overweight (including obesity; WHO definitions) ranged from 18% to 57% among boys and from 18% to 50% among girls; 6 - 31% of boys and 5 - 21% of girls were obese. Southern European countries had the highest overweight prevalence. Between rounds, the absolute change in mean BMI (range: from -0.4 to +0.3) and BMI-for-age Z-scores (range: from -0.21 to +0.14) varied statistically significantly across countries. The highest significant decrease in BMI-for-age Z-scores was found in countries with higher absolute BMI values and the highest significant increase in countries with lower BMI values. The highest significant decrease in overweight prevalence was observed in Italy, Portugal and Slovenia and the highest significant increase in Latvia and Norway. Changes in BMI and prevalence of overweight over a two-year period varied significantly among European countries. It may be that countries with higher prevalence of overweight in COSI Round 1 have implemented interventions to try to remedy this situation.

  6. In vivo 1D and 2D correlation MR spectroscopy of the soleus muscle at 7T

    PubMed Central

    Ramadan, Saadallah; Ratai, Eva-Maria; Wald, Lawrence L.; Mountford, Carolyn E.

    2013-01-01

    Aim This study aims to (1) undertake and analyse 1D and 2D MR correlation spectroscopy from human soleus muscle in vivo at 7T, and (2) determine T1 and T2 relaxation time constants at 7T field strength due to their importance in sequence design and spectral quantitation. Method Six healthy, male volunteers were consented and scanned on a 7T whole-body scanner (Siemens AG, Erlangen, Germany). Experiments were undertaken using a 28 cm diameter detunable birdcage coil for signal excitation and an 8.5 cm diameter surface coil for signal reception. The relaxation time constants, T1 and T2 were recorded using a STEAM sequence, using the ‘progressive saturation’ method for the T1 and multiple echo times for T2. The 2D L-Correlated SpectroscopY (L-COSY) method was employed with 64 increments (0.4 ms increment size) and eight averages per scan, with a total time of 17 min. Results T1 and T2 values for the metabolites of interest were determined. The L-COSY spectra obtained from the soleus muscle provided information on lipid content and chemical structure not available, in vivo, at lower field strengths. All molecular fragments within multiple lipid compartments were chemically shifted by 0.20–0.26 ppm at this field strength. 1D and 2D L-COSY spectra were assigned and proton connectivities were confirmed with the 2D method. Conclusion In vivo 1D and 2D spectroscopic examination of muscle can be successfully recorded at 7T and is now available to assess lipid alterations as well as other metabolites present with disease. T1 and T2 values were also determined in soleus muscle of male healthy volunteers. PMID:20206561

  7. Simultaneous observation of glutamate, gamma-aminobutyric acid, and glutamine in human brain at 4.7 T using localized two-dimensional constant-time correlation spectroscopy.

    PubMed

    Watanabe, H; Takaya, N; Mitsumori, F

    2008-06-01

    Localized two-dimensional constant-time correlation spectroscopy (CT-COSY) was used to resolve glutamate (Glu), gamma-aminobutyric acid (GABA), and glutamine (Gln) in the human brain at 4.7 T. In this method, three-dimensional localization was achieved using three radio frequency pulses of the CT-COSY module for slice selection. As this sequence could decouple JHH along the F1 direction, peak resolution of metabolites was improved even on a magnitude-mode display. In experiments on a phantom containing N-acetylaspartate, creatine, Glu, Gln, and GABA with a constant time delay (Tct) of 110 ms, cross peaks of Glu, Gln, and GABA were obtained on a spectrum processed with standard sine-bell windows, which emphasize sine-dependent signals along the t2 direction. In contrast, diagonal peaks of Glu C4H at 2.35 ppm, GABA C2H at 2.28 ppm, and Gln C4H at 2.44 ppm were resolved on a spectrum processed with Gaussian windows, which emphasize cosine-dependent signals along t2. Human brain spectra were obtained from a 27 mL voxel within the parieto-occipital region using a volume transverse electromagnetic (TEM) coil for both transmission and reception. Tct was 110 ms; the total scan time was 30 min. Diagonal peaks of Glu C4H, GABA C2H, and Gln C4H were also resolved on the spectrum processed with Gaussian windows. These results show that the localized two-dimensional CT-COSY method featuring 1H decoupling along the F1 direction could resolve Glu, GABA, and Gln signals in the human brain. Copyright (c) 2008 John Wiley & Sons, Ltd.

  8. Evaluation of Existing Image Matching Methods for Deriving Glacier Surface Displacements Globally from Optical Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Heid, T.; Kääb, A.

    2011-12-01

    Automatic matching of images from two different times is a method that is often used to derive glacier surface velocity. Nearly global repeat coverage of the Earth's surface by optical satellite sensors now opens the possibility for global-scale mapping and monitoring of glacier flow with a number of applications in, for example, glacier physics, glacier-related climate change and impact assessment, and glacier hazard management. The purpose of this study is to compare and evaluate different existing image matching methods for glacier flow determination over large scales. The study compares six different matching methods: normalized cross-correlation (NCC), the phase correlation algorithm used in the COSI-Corr software, and four other Fourier methods with different normalizations. We compare the methods over five regions of the world with different representative glacier characteristics: Karakoram, the European Alps, Alaska, Pine Island (Antarctica) and southwest Greenland. Landsat images are chosen for matching because they expand back to 1972, they cover large areas, and at the same time their spatial resolution is as good as 15 m for images after 1999 (ETM+ pan). Cross-correlation on orientation images (CCF-O) outperforms the three similar Fourier methods, both in areas with high and low visual contrast. NCC experiences problems in areas with low visual contrast, areas with thin clouds or changing snow conditions between the images. CCF-O has problems on narrow outlet glaciers where small window sizes (about 16 pixels by 16 pixels or smaller) are needed, and it also obtains fewer correct matches than COSI-Corr in areas with low visual contrast. COSI-Corr has problems on narrow outlet glaciers and it obtains fewer correct matches compared to CCF-O when thin clouds cover the surface, or if one of the images contains snow dunes. In total, we consider CCF-O and COSI-Corr to be the two most robust matching methods for global-scale mapping and monitoring of glacier

  9. Structure of a polysaccharide from Urtica fissa determined by NMR spectra.

    PubMed

    Wang, Yan-Liang; Li, Li; Cheng, Xiao-Chen; Lu, Yu-Xin; Zhang, Qing-Lin

    2012-01-01

    A polysaccharide, isolated and purified from the aqueous extract of nettle plant Urtica fissa, was found to consist of D-glucose and D-arabinose. Molecular weight was determined to be Mn 4140. The NMR experiments (¹H, ¹³C, ¹H--¹H COSY, TOCSY, HSQC, NOESY, and HMBC) revealed the structure as the following repeating unit: -->6)-α-D-Glcp-(1-->6)-α-D-Glcp-(1-->6)-β-D-Glcp--(1-->5)-β-D-Araf-(1-->3)-β-D-Glcp-(1-->

  10. Synthesis, characterization, and photophysical properties of a thiophene-functionalized bis(pyrazolyl) pyridine (BPP) tricarbonyl rhenium(I) complex.

    PubMed

    Lytwak, Lauren A; Stanley, Julie M; Mejía, Michelle L; Holliday, Bradley J

    2010-09-07

    A bromo tricarbonyl rhenium(I) complex with a thiophene-functionalized bis(pyrazolyl) pyridine ligand (L), ReBr(L)(CO)(3) (1), has been synthesized and characterized by variable temperature and COSY 2-D (1)H NMR spectroscopy, single-crystal X-ray diffraction, and photophysical methods. Complex 1 is highly luminescent in both solution and solid-state, consistent with phosphorescence from an emissive (3)MLCT excited state with an additional contribution from a LC (3)(pi-->pi*) transition. The single-crystal X-ray diffraction structure of the title ligand is also reported.

  11. Antiproliferative triterpene saponins from Entada africana.

    PubMed

    Cioffi, Giuseppina; Dal Piaz, Fabrizio; De Caprariis, Paolo; Sanogo, Rokia; Marzocco, Stefania; Autore, Giuseppina; De Tommasi, Nunziatina

    2006-09-01

    Nine new ester saponins (1-9) were isolated from the roots of Entada africana. Their structures were elucidated by 1D and 2D NMR experiments including 1D and 2D TOCSY, DQF-COSY, HSQC, and HMBC spectroscopy, as well as ESIMS analysis, and chemical methods. The aglycon moieties were found to be echinocystic acid for compounds 1, 2, 4-6, 8, and 9 and acacic acid for 3 and 7. All isolated compounds were tested for their antiproliferative activity against the J774.A1, HEK-293, and WEHI-164 cell lines. Moderate to high cytotoxic potency was found for almost all compounds tested.

  12. Cytotoxic saponins from Schefflera fagueti.

    PubMed

    Cioffi, Giuseppina; Braca, Alessandra; Autore, Giuseppina; Morelli, Ivano; Pinto, Aldo; Venturella, Fabio; De Tommasi, Nunziatina

    2003-08-01

    Six new lupane (1 - 4) and oleanane saponins (5 and 6) were isolated from the aerial parts of Schefflera fagueti Baill. (Araliaceae). Their structures were determined by 2D-NMR spectroscopy (DQF-COSY, 1D-TOCSY, 2D-HOHAHA, 1D-ROESY, HSQC, HMBC). The antiproliferative activity of compounds 1 - 6 and of their prosapogenins (1a - 6a) was evaluated using three continuous murine and human culture cell lines J774, HEK-293, WEHI-164. Oleanane saponins 5 and 6 were the most active, showing significant inhibitory effects on all cell lines, while their prosapogenins 5a and 6a demonstrated minor activity.

  13. Complete NMR assignment of a bisecting hybrid-type oligosaccharide transferred by Mucor hiemalis endo-β-N-acetylglucosaminidase.

    PubMed

    Yamanoi, Takashi; Oda, Yoshiki; Katsuraya, Kaname; Inazu, Toshiyuki; Yamamoto, Kenji

    2016-06-02

    This study describes the complete nuclear magnetic resonance (NMR) spectral assignment of a bisecting hybrid-type oligosaccharide 1, transferred by Mucor hiemalis endo-β-N-acetylglucosaminidase (Endo-M). Through (1)H- and (13)C-NMR, DQF-COSY, HSQC, HMBC, TOCSY, and NOESY experiments, we determine the structure of the glycoside linkage formed by the Endo-M transglycosylation, i.e., the connection between GlcNAc and GlcNAc in oligosaccharide 1. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Towards Polarized Antiprotons at FAIR

    NASA Astrophysics Data System (ADS)

    Rathmann, Frank

    2007-06-01

    Understanding the interplay of the nuclear interaction with polarized protons and the electromagnetic interaction with polarized electrons in polarized atoms is crucial to progress towards the PAX goal to eventually produce stored polarized antiproton beams at FAIR. Presently, there exist two competing theoretical scenarios: one with substantial spin filtering of (anti)protons by atomic electrons, and a second one suggesting a self-cancellation of the electron contribution to spin filtering. After a brief review of the PAX physics case for polarized antiprotons at FAIR, a detailed discussion of future investigations, including spin-filtering experiments at COSY-Jülich and at the AD of CERN is presented.

  15. Electromagnetic Simulation and Design of a Novel Waveguide RF Wien Filter for Electric Dipole Moment Measurements of Protons and Deuterons

    NASA Astrophysics Data System (ADS)

    Slim, J.; Gebel, R.; Heberling, D.; Hinder, F.; Hölscher, D.; Lehrach, A.; Lorentz, B.; Mey, S.; Nass, A.; Rathmann, F.; Reifferscheidt, L.; Soltner, H.; Straatmann, H.; Trinkel, F.; Wolters, J.

    2016-08-01

    The conventional Wien filter is a device with orthogonal static magnetic and electric fields, often used for velocity separation of charged particles. Here we describe the electromagnetic design calculations for a novel waveguide RF Wien filter that will be employed to solely manipulate the spins of protons or deuterons at frequencies of about 0.1-2 MHz at the COoler SYnchrotron COSY at Jülich. The device will be used in a future experiment that aims at measuring the proton and deuteron electric dipole moments, which are expected to be very small. Their determination, however, would have a huge impact on our understanding of the universe.

  16. ABC effect and resonance d*(2380)

    NASA Astrophysics Data System (ADS)

    Bashkanov, M.; Clement, H.; Doroshkevich, E.; Skorodko, T.

    2017-11-01

    A new state in the two-baryon system with mass 2380 MeV and width 80 MeV has been detected in the experiments at the Juelich Cooler Synchrotron (COSY). The new particle denoted now d*(2380) has quantum numbers I( J p ) = 0(3+). The total cross sections for the d and 4He fusion reactions show similar to each other resonance-like energy dependence. The resonance-like structure is sensed in the double-pionic fusion channels and polarized np scattering.

  17. NASA Test Conductor Monitoring DIME competition

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A NASA test conductor at the top of the 2.2-second Drop Tower monitors a student lecture at a lower level. This was part of the Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  18. DIME Students Participate in SCUBA Lesson Spring 2002

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In addition to drop tower activities, students assembled a plastic pipe structure underwater in a SCUBA exercise similar to training astronauts receive at NASA Johnson Space Center. This was part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  19. Student-Designed Fluid Experiment for DIME Competition

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Test tubes to hold different types of fluids while in free-fall were among the student-designed items for the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  20. DIME Students Witness Test Drop

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Students watch a test run on their experiment before the actual drop. They designed and built their apparatus to fit within a NASA-provided drop structure. This was part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  1. Structural study of ethyl 3-methyl-9-oxo-3-azabicyclo63.3.19nonane-1-carboxylate by two-dimensional NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Arias-Pérez, M. S.; Alejo, A.; Gálvez, E.; Pérez, S. M.; Santos, M. J.

    1995-04-01

    Ethyl 3-methyl-9-oxo-3-azabicyclo[3.3.1]nonane-1-carboxylate has been studied by 1H, 13C and 2D NMR spectroscopy in order to establish its conformational behaviour. The combined use of COSY and 1H- 13C correlation spectra helped in the unambiguous and complete assignment of the bicyclic carbon and proton resonances. It is found that the piperidone ring displays a slightly fattened chair conformation with the N-methyl group in the equatorial position, while a twist-chair form seems to be favoured for the cyclohexanone one. Two preferred orientations migth be proposed for the ethoxycarbonyl moiety.

  2. Advanced wave field sensing using computational shear interferometry

    NASA Astrophysics Data System (ADS)

    Falldorf, Claas; Agour, Mostafa; Bergmann, Ralf B.

    2014-07-01

    In this publication we give a brief introduction into the field of Computational Shear Interferometry (CoSI), which allows for determining arbitrary wave fields from a set of shear interferograms. We discuss limitations of the method with respect to the coherence of the underlying wave field and present various numerical methods to recover it from its sheared representations. Finally, we show experimental results on Digital Holography of objects with rough surface using a fiber coupled light emitting diode and quantitative phase contrast imaging as well as numerical refocusing in Differential Interference Contrast (DIC) microscopy.

  3. One new 19-nor cucurbitane-type triterpenoid from the stems of Momordica charantia.

    PubMed

    Li, Yong-chao; Xu, Xin-juan; Yang, Jing; Wu, Xing-gang; Fu, Qing-yun

    2016-01-01

    One new 19-nor cucurbitane-type triterpenoid (3β,9β,25-trihydroxy-7β-methoxy-19-nor-cucurbita-5,23(E)-diene) (1), together with other six known cucurbitane-type triterpenoids (2-7), were isolated from the stems of Momordica charantia L. The chemical structure of 1 was elucidated by extensive 1D NMR and 2D NMR (HSQC, HMBC, COSY and ROESY), MS experiments. Using MTT assay, compound 1 exhibited weak cytotoxicity against HL-60, A-549, and SK-BR-3 cell lines with the IC50 values at 27.3, 32.7 and 26.6 μM, respectively.

  4. DIME Participant Builds a Potential Drop Tower Candidate

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A student assembles a Lego (TM) Challenge device designed to operate in the portable drop tower demonstrator as part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  5. DIME Participants Working on a Legos(TM) Challenge

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Members from all four teams were mixed into pairs to work on a Lego (TM) Challenge device to operate in the portable drop tower demonstrator (background). These two team members are about to try out their LEGO (TM) creation. This was part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  6. Microgravity

    NASA Image and Video Library

    2002-08-07

    A student assembles a Lego (TM) Challenge device designed to operate in the portable drop tower demonstrator as part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  7. Microgravity

    NASA Image and Video Library

    2002-08-07

    Two students show the Lego (TM) Challenge device they designed and built to operate in the portable drop tower demonstrator as part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  8. Structural studies of O-polysaccharide isolated from Cronobacter sakazakii Sequence Type 12 from a case of neonatal necrotizing enterocolitis.

    PubMed

    Marszewska, Kinga; Czerwicka, Małgorzata; Forsythe, Stephen J; Ossowska, Karolina; Dziadziuszko, Halina; Kaczyński, Zbigniew

    2015-04-30

    The O-polysaccharide (OPS) of Cronobacter sakazakii NTU 696 (Sequence Type 12) from a case of neonatal necrotizing enterocolitis was isolated from the polysaccharide fraction obtained after lipopolysaccharide (LPS) hydrolysis. Purified OPS was analyzed by NMR spectroscopy ((1)H, COSY, TOCSY, NOESY, HSQC, HSQC-TOCSY and HMBC experiments) and chemical methods. Obtained monosaccharide derivatives analyzed by gas chromatography and gas chromatography-mass spectrometry allowed the identification of six sugar components. Performed experiments enabled to establish a structure of the OPS repeating unit of C. sakazakii NTU 696, as: [structure: see text]. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. DIME Participant Prepares Experiment

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A Bay High School team member prepares the oil and water samples for their next drop operation as part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  10. Combustion Science

    NASA Image and Video Library

    2002-08-07

    Interior of a combustion experiment apparatus used in the 2.2-second drop tower at NASA's Glenn Research Center. This was shown to students participating in the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  11. Structural Characterization of the Degradation Products of a Minor Natural Sweet Diterpene Glycoside Rebaudioside M under Acidic Conditions

    PubMed Central

    Prakash, Indra; Chaturvedula, Venkata Sai Prakash; Markosyan, Avetik

    2014-01-01

    Degradation of rebaudioside M, a minor sweet component of Stevia rebaudiana Bertoni, under conditions that simulated extreme pH and temperature conditions has been studied. Thus, rebaudioside M was treated with 0.1 M phosphoric acid solution (pH 2.0) and 80 °C temperature for 24 h. Experimental results indicated that rebaudioside M under low pH and higher temperature yielded three minor degradation compounds, whose structural characterization was performed on the basis of 1D (1H-, 13C-) & 2D (COSY, HSQC, HMBC) NMR, HRMS, MS/MS spectral data as well as enzymatic and acid hydrolysis studies. PMID:24424316

  12. Design of interior-functionalized fully acetylated dendrimers for anticancer drug delivery.

    PubMed

    Hu, Jingjing; Su, Yunzhang; Zhang, Hongfeng; Xu, Tongwen; Cheng, Yiyun

    2011-12-01

    In this study, dendrimers was synthesized by introducing functional groups into the interior pockets of fully acetylated dendrimers. NMR techniques including COSY and 2D-NOESY revealed the molecular structures of the synthesized dendrimers and the encapsulation of guest molecule such as methotrexate within their interior pockets. The synthesized polymeric nanocarriers showed much lower cytotoxicity on two cell lines than cationic dendrimers, and exhibited better performance than fully acetylated dendrimers in the sustained release of methotrexate. The results provided a new strategy in the design of non-toxic dendrimers with high performance in the delivery of anti-cancer drugs for clinical applications. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. DIME Students Show Off their Lego(TM) Challenge Creation

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Two students show the Lego (TM) Challenge device they designed and built to operate in the portable drop tower demonstrator as part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  14. Microgravity

    NASA Image and Video Library

    2002-08-07

    Members from all four teams were mixed into pairs to work on a Lego (TM) Challenge device to operate in the portable drop tower demonstrator (background). These two team members are about to try out their LEGO (TM) creation. This was part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  15. Reduction of space charge effects and tests of larger samples of photomultipliers for the EDDA experiment

    NASA Astrophysics Data System (ADS)

    Ackerstaff, K.; Bisplinghoff, J.; Bollmann, R.; Cloth, P.; Dohrmann, F.; Diehl, O.; Dorner, G.; Drüke, V.; Engelhardt, H. J.; Eisenhardt, S.; Ernst, J.; Eversheim, P. D.; Filges, D.; Fritz, S.; Gasthuber, M.; Gebel, R.; Gross, A.; Gross-Hardt, R.; Hinterberger, F.; Jahn, R.; Lahr, U.; Langkau, R.; Lippert, G.; Mayer-Kuckuk, T.; Maschuw, R.; Mertler, G.; Metsch, B.; Mosel, F.; Paetz gen. Schieck, H.; Petry, H. R.; Prasuhn, D.; v. Przewoski, B.; Radtke, M.; Rohdjess, H.; Rosendaal, D.; von Rossen, P.; Scheid, H.; Schirm, N.; Schwandt, F.; Scobel, W.; Theis, D.; Weber, J.; Wiedmann, W.; Woller, K.; Ziegler, R.; EDDA Collaboration

    1993-10-01

    For the EDDA experiment at COSY, the response of the small, linear focused photomultipliers Hamamatsu R 1450 and R 1355 has been studied with fast light pulses generating yields up to 2 × 10 3 photoelectrons/cm 2 or peak currents of 24 mA. Linearity was obtained with a tapered bleeder chain at a tolerable loss of gain. The serial test of altogether 140 photomultipliers revealed the close correlation between single electron and amplitude resolution. The influence of the photoelectron statistics on this correlation is discussed.

  16. Feasibility of maintaining in-plane polarization for a storage ring EDM search

    NASA Astrophysics Data System (ADS)

    Stephenson, Edward; Storage Ring EDM Collaboration

    2014-09-01

    A search for an electric dipole moment (EDM) on charged particles using a storage ring requires beam polarization lifetimes approaching 1000 s for in-plane polarization. A feasibility study using beam bunching and sextupole field adjustment is underway with a 0.97-GeV/c vector-polarized deuteron beam at COSY. The polarimeter consists of a thick carbon target positioned at the edge of the beam and the EDDA scintillation detectors. The DAQ system assigns a clock time to each polarimeter event. Once calibrated against the RF-cavity, the clock time is used to select events associated with a maximal sideways polarization (precessing at 120 kHz). With this tool, the in-plane polarization magnitude is tracked versus time. Electron cooling reduces the depolarization from finite emittance and second-order momentum spread acting through synchrotron oscillations. Further lifetime improvement to the level of hundreds of seconds is achieved by adjusting sextupole fields located in the COSY ring arcs at places of large transverse beta functions and dispersion. The dependence of the reciprocal of the lifetime on sextupole field strength is nearly linear, permitting an easy location of the best field values. These typically occur near loci of zero chromaticity. A search for an electric dipole moment (EDM) on charged particles using a storage ring requires beam polarization lifetimes approaching 1000 s for in-plane polarization. A feasibility study using beam bunching and sextupole field adjustment is underway with a 0.97-GeV/c vector-polarized deuteron beam at COSY. The polarimeter consists of a thick carbon target positioned at the edge of the beam and the EDDA scintillation detectors. The DAQ system assigns a clock time to each polarimeter event. Once calibrated against the RF-cavity, the clock time is used to select events associated with a maximal sideways polarization (precessing at 120 kHz). With this tool, the in-plane polarization magnitude is tracked versus time. Electron

  17. Determining beam parameters in a storage ring with a cylindrical hodoscope using elastic proton proton scattering

    NASA Astrophysics Data System (ADS)

    Rohdjeß, H.; Albers, D.; Bisplinghoff, J.; Bollmann, R.; Büßer, K.; Diehl, O.; Dohrmann, F.; Engelhardt, H.-P.; Eversheim, P. D.; Gasthuber, M.; Greiff, J.; Groß, A.; Groß-Hardt, R.; Hinterberger, F.; Igelbrink, M.; Langkau, R.; Maier, R.; Mosel, F.; Müller, M.; Münstermann, M.; Prasuhn, D.; von Rossen, P.; Scheid, H.; Schirm, N.; Schwandt, F.; Scobel, W.; Trelle, H. J.; Wellinghausen, A.; Wiedmann, W.; Woller, K.; Ziegler, R.

    2006-01-01

    The EDDA-detector at the cooler-synchrotron COSY/Jülich has been operated with an internal CH2 fiber target to measure proton-proton elastic scattering differential cross-sections. For data analysis knowledge of beam parameters, like position, width and angle, are indispensable. We have developed a method to obtain these values with high precision from the azimuthal and polar angles of the ejectiles only, by exploiting the coplanarity of the two final-state protons with the beam and the kinematic correlation. The formalism is described and results for beam parameters obtained during beam acceleration are given.

  18. Direct reconstruction of p-p elastic scattering amplitudes at 1.8 and 2.1 GeV

    NASA Astrophysics Data System (ADS)

    Ghahramany, Nader; Forozani, Ghasem

    2000-06-01

    The direct reconstruction of the proton-proton elastic-scattering complex amplitudes is carried out at 1.8 and 2.1 GeV. Five independent amplitudes both in helicity and transversity frame were obtained by using an extensive set of data measured recently at SATURNE II and by the EDDA (COSY) Collaboration. The real and imaginary parts of the amplitudes are plotted versus different interpolated c.m. angles for both frames. Four distinct sets of solutions exist, one of which is chosen on the basis of minimum χ2.

  19. Growing Cobalt Silicide Columns In Silicon

    NASA Technical Reports Server (NTRS)

    Fathauer, Obert W.

    1991-01-01

    Codeposition by molecular-beam epitaxy yields variety of structures. Proposed fabrication process produces three-dimensional nanometer-sized structures on silicon wafers. Enables control of dimensions of metal and semiconductor epitaxial layers in three dimensions instead of usual single dimension (perpendicular to the plane of the substrate). Process used to make arrays of highly efficient infrared sensors, high-speed transistors, and quantum wires. For fabrication of electronic devices, both shapes and locations of columns controlled. One possible technique for doing this electron-beam lithography, see "Making Submicron CoSi2 Structures on Silicon Substrates" (NPO-17736).

  20. Microgravity

    NASA Image and Video Library

    2002-08-07

    A NASA test conductor at the top of the 2.2-second Drop Tower monitors a student lecture at a lower level. This was part of the Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  1. Microgravity

    NASA Image and Video Library

    2002-08-07

    A Bay High School team member prepares the oil and water samples for their next drop operation as part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  2. 1H and 13C NMR spectral data of new saponins from Cordia piauhiensis.

    PubMed

    Santos, Renata P; Silveira, Edilberto R; Uchôa, Daniel Esdras de A; Pessoa, Otília Deusdênia L; Viana, Francisco Arnaldo; Braz-Filho, Raimundo

    2007-08-01

    Two new bidesmoside triterpenoid saponins were isolated from stems of Cordia piauhiensis. Their structures, characterized as 3-O-alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl pomolic acid 28-O-beta-D-glucopyranosyl ester (1) and 3-O-alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranosyl ester (2), were unequivocally established after extensive NMR (1H, 13C, DEPT 135 degrees, COSY, HSQC, HMBC, TOCSY, and NOESY) studies. Copyright 2007 John Wiley & Sons, Ltd.

  3. 1H and 13C NMR assignments for two new cordiaquinones from roots of Cordia leucocephala.

    PubMed

    Diniz, Jaécio Carlos; Viana, Francisco Arnaldo; Oliveira, Odaci Fernandes; Maciel, Maria Aparecida M; Torres, Maria da Conceição de Menezes; Braz-Filho, Raimundo; Silveira, Edilberto R; Pessoa, Otília Deusdênia L

    2009-02-01

    From the roots of Cordia leucocephala (Boraginaceae), two new meroterpenoid naphthoquinones, 6-[10-(12,12-dimethyl-13alpha-hydroxy-16-methenyl-cyclohexyl)ethyl]-1,4-naphthalenedione (cordiaquinone L) and 5-methyl-6-[10-(12,12-dimethyl-13beta-hydroxy-16-methenyl-cyclohexyl)methyl-1,4-naphthalenedione (cordiaquinone M) were isolated. Their structures were elucidated after detailed 1D and 2D NMR (COSY, HSQC, HMBC and NOESY) data analyses and comparison with literature data for analogous compounds. 2008 John Wiley & Sons, Ltd.

  4. Analysis of the Shallow Slip Deficit Using Sub-Pixel Image Correlation:examples from various large continental strike-slip earthquakes

    NASA Astrophysics Data System (ADS)

    Milliner, C. W.; Hollingsworth, J.; Dolan, J. F.; Leprince, S.; Ayoub, F.; Avouac, J.

    2012-12-01

    We use the optical image correlation technique to analyze the near-field displacement field for a variety of large (Mw 7+) continental strike-slip earthquakes, to better determine the contribution of distributed deformation to coseismic surface ruptures. Various satellite datasets are correlated using the COSI-Corr software package, including WorldView, Quickbird, SPOT and Landsat7 imagery, along with de-classified KH-9 spy satellite imagery and aerial photos, allowing us to investigate earthquakes as far back as 1976. The variety of datasets used highlights the versatility of COSI-Corr for measuring displacements at the Earth's surface. The following earthquakes are investigated: 1976 Guatemala (Mw 7.5), 1990 Luzon (Mw 7.4), 1992 Landers (Mw 7.3), 1995 Sakhalin (Mw 7.0), 1997 Zirkuh (Mw 7.2), 1999 Izmit (Mw 7.6), 1999 Hector Mine (Mw 7.1), 1999 Duzce (Mw 7.1), 2001 Kokoxilli (Mw 7.1) and 2002 Denali (Mw 7.8). For each event we examine the surface displacement field produced by COSI-Corr, and compare them with published field measurements to assess the component of distributed deformation that may be routinely missed by geologists when collecting data in the field. These results also complement surface displacements determined using InSAR, which commonly de-correlates at distances of 1-2 km from the fault rupture. Fault displacements are extracted from the displacement maps using a new tool written for MATLAB, which extracts the maximum and minimum values on either side of the fault, as well as the distance between these points, thus giving a potential measure of the total width of the deforming zone. Where possible, we determine the total geological displacements for each fault through analysis of satellite data, geological maps and published results, thus allowing an assessment of the structural maturity for each fault. The difference between field measurements and COSI-Corr-derived measurements of the coseismic displacement field are compared with geological

  5. DIME 2002 Participants at Glenn Research Center

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Students from the four teams pose in front of he NASA Glenn Administration Building alongside the NASA Glenn Time Capsule. The students participated in the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  6. Towards Polarised Antiprotons: Machine Developments for Spin-Filtering Studies

    NASA Astrophysics Data System (ADS)

    Lenisa, Paolo

    2016-02-01

    We address the commissioning of the experimental equipment and the machine studies required for the first spin-filtering experiment with protons at the COSY ring in Jülich (Germany) at a beam kinetic energy of 49.3 MeV. The implementation of a low-beta insertion made it possible to achieve beam lifetimes of 8000 s in the presence of a dense polarized hydrogen storage cell target. The developed techniques can be directly applied to antiproton machines and allow for the determination of the spin-dependent pbar-p cross sections via spin-filtering.

  7. Microgravity

    NASA Image and Video Library

    2002-08-08

    In addition to drop tower activities, students assembled a plastic pipe structure underwater in a SCUBA exercise similar to training astronauts receive at NASA Johnson Space Center. This was part of the second Dropping in a Microgravity Environment (DIME) competition held April 23-25, 2002, at NASA's Glenn Research Center. Competitors included two teams from Sycamore High School, Cincinnati, OH, and one each from Bay High School, Bay Village, OH, and COSI Academy, Columbus, OH. DIME is part of NASA's education and outreach activities. Details are on line at http://microgravity.grc.nasa.gov/DIME_2002.html.

  8. Structure and backbone dynamics of a microcrystalline metalloprotein by solid-state NMR.

    PubMed

    Knight, Michael J; Pell, Andrew J; Bertini, Ivano; Felli, Isabella C; Gonnelli, Leonardo; Pierattelli, Roberta; Herrmann, Torsten; Emsley, Lyndon; Pintacuda, Guido

    2012-07-10

    We introduce a new approach to improve structural and dynamical determination of large metalloproteins using solid-state nuclear magnetic resonance (NMR) with (1)H detection under ultrafast magic angle spinning (MAS). The approach is based on the rapid and sensitive acquisition of an extensive set of (15)N and (13)C nuclear relaxation rates. The system on which we demonstrate these methods is the enzyme Cu, Zn superoxide dismutase (SOD), which coordinates a Cu ion available either in Cu(+) (diamagnetic) or Cu(2+) (paramagnetic) form. Paramagnetic relaxation enhancements are obtained from the difference in rates measured in the two forms and are employed as structural constraints for the determination of the protein structure. When added to (1)H-(1)H distance restraints, they are shown to yield a twofold improvement of the precision of the structure. Site-specific order parameters and timescales of motion are obtained by a gaussian axial fluctuation (GAF) analysis of the relaxation rates of the diamagnetic molecule, and interpreted in relation to backbone structure and metal binding. Timescales for motion are found to be in the range of the overall correlation time in solution, where internal motions characterized here would not be observable.

  9. Effect of chemical and physical heterogeneities on colloid-facilitated cesium transport

    DOE PAGES

    Rod, Kenton; Um, Wooyong; Chun, Jaehun; ...

    2018-03-31

    A set of column experiments was conducted to investigate the chemical and physical heterogeneity effect on colloid facilitated transport under slow pore velocity conditions. Pore velocities were kept below 100 cm d -1 for all experiments. Glass beads were packed into columns establishing four different conditions: 1) homogeneous, 2) mixed physical heterogeneity, 3) sequentially layered physical heterogeneity, and 4) chemical heterogeneity. The homogeneous column was packed with glass beads (diameter 500–600 μm), and physical heterogeneities were created by sequential layering or mixing two sizes of glass bead (500–600 μm and 300–400 μm). A chemical heterogeneity was created using 25% ofmore » the glass beads coated with hydrophobic molecules (1H-1H-2H-2H-perfluorooctyltrichlorosilane) mixed with 75% pristine glass beads (all 500–600 μm). Input solution with 0.5 mM CsI and 50 mg L -1 colloids (1-μm diameter SiO 2) was pulsed into columns under saturated conditions. The physical heterogeneity in the packed glass beads retarded the transport of colloids compared to homogeneous (R = 25.0), but showed only slight differences between sequentially layered (R = 60.7) and mixed heterogeneity(R = 62.4). The column with the chemical, hydrophobic/hydrophilic, heterogeneity removed most of the colloids from the input solution. All column conditions stripped Cs from colloids onto the column matrix of packed glass beads.« less

  10. Effect of chemical and physical heterogeneities on colloid-facilitated cesium transport

    SciTech Connect

    Rod, Kenton; Um, Wooyong; Chun, Jaehun

    A set of column experiments was conducted to investigate the chemical and physical heterogeneity effect on colloid facilitated transport under slow pore velocity conditions. Pore velocities were kept below 100 cm d -1 for all experiments. Glass beads were packed into columns establishing four different conditions: 1) homogeneous, 2) mixed physical heterogeneity, 3) sequentially layered physical heterogeneity, and 4) chemical heterogeneity. The homogeneous column was packed with glass beads (diameter 500–600 μm), and physical heterogeneities were created by sequential layering or mixing two sizes of glass bead (500–600 μm and 300–400 μm). A chemical heterogeneity was created using 25% ofmore » the glass beads coated with hydrophobic molecules (1H-1H-2H-2H-perfluorooctyltrichlorosilane) mixed with 75% pristine glass beads (all 500–600 μm). Input solution with 0.5 mM CsI and 50 mg L -1 colloids (1-μm diameter SiO 2) was pulsed into columns under saturated conditions. The physical heterogeneity in the packed glass beads retarded the transport of colloids compared to homogeneous (R = 25.0), but showed only slight differences between sequentially layered (R = 60.7) and mixed heterogeneity(R = 62.4). The column with the chemical, hydrophobic/hydrophilic, heterogeneity removed most of the colloids from the input solution. All column conditions stripped Cs from colloids onto the column matrix of packed glass beads.« less

  11. NMR Chemical Exchange as a Probe for Ligand-Binding Kinetics in a Theophylline-Binding RNA Aptamer

    PubMed Central

    Latham, Michael P.; Zimmermann, Grant R.; Pardi, Arthur

    2009-01-01

    The apparent on- and off-rate constants for theophylline binding to its RNA aptamer in the absence of Mg2+ were determined here by 2D 1H-1H NMR ZZ-exchange spectroscopy. Analysis of the build-up rate of the exchange cross peaks for several base-paired imino protons in the RNA yielded an apparent kon of 600 M-1 s-1. This small apparent kon results from the free RNA existing as a dynamic equilibrium of inactive states rapidly interconverting with a low population of active species. The data here indicate that the RNA aptamer employs a conformational selection mechanism for binding theophylline in the absence of Mg2+. The kinetic data here also explain a very unusual property of this RNA-theophylline system, slow exchange on the NMR chemical shift timescale for a weak-binding complex. To our knowledge, it is unprecedented to have such a weak binding complex (Kd ≈ 3.0 mM at 15 °C) show slow exchange on the NMR chemical shift timescale, but the results clearly demonstrate that slow exchange and weak binding are readily rationalized by a small kon. Comparisons with other ligand-receptor interactions are presented. PMID:19317486

  12. Unearthing a Well-Defined Highly Active Bimetallic W/Ti Precatalyst Anchored on a Single Silica Surface for Metathesis of Propane.

    PubMed

    Samantaray, Manoja K; Kavitake, Santosh; Morlanés, Natalia; Abou-Hamad, Edy; Hamieh, Ali; Dey, Raju; Basset, Jean-Marie

    2017-03-08

    Two compatible organometallic complexes, W(Me) 6 (1) and TiNp 4 (2), were successively anchored on a highly dehydroxylated single silica support (SiO 2-700 ) to synthesize the well-defined bimetallic precatalyst [(≡Si-O-)W(Me) 5 (≡Si-O-)Ti(Np) 3 ] (4). Precatalyst 4 was characterized at the molecular level using advanced surface organometallic chemistry (SOMC) characterization techniques. The strong autocorrelation observed between methyl of W and Ti in 1 H- 1 H multiple-quantum NMR spectra demonstrates that W and Ti species are in close proximity to each other. The bimetallic precatalyst 4, with a turnover number (TON) of 9784, proved to be significantly more efficient than the silica-supported monometallic catalyst [(≡Si-O-)W(Me) 5 ] (3), with a TON of 98, for propane metathesis at 150 °C in a flow reactor. The dramatic improvement in the activity signifies the cooperativity between Ti and W and indicates that the key step of alkane metathesis (C-H bond activation followed by β-H elimination) occurs on Ti, followed by olefin metathesis, which occurs on W. We have demonstrated the influence and importance of proximity of Ti to W for achieving such a significantly high activity. This is the first report demonstrating the considerably high activity (TON = 9784) in propane metathesis at moderate temperature (150 °C) using a well-defined bimetallic system prepared via the SOMC approach.

  13. (+)-Ascosalitoxin and vermelhotin, a calmodulin inhibitor, from an endophytic fungus isolated from Hintonia latiflora.

    PubMed

    Leyte-Lugo, Martha; González-Andrade, Martín; González, María del Carmen; Glenn, Anthony E; Cerda-García-Rojas, Carlos M; Mata, Rachel

    2012-09-28

    Chemical investigation of the endophytic MEXU 26343, isolated from the medicinal plant Hintonia latiflora, yielded the known polyketide vermelhotin (1) and a new salicylic aldehyde derivative, namely, 9S,11R-(+)-ascosalitoxin (2). The structure and absolute configuration of the new compound were established through extensive NMR spectroscopy and molecular modeling calculations at the DFT B3LYP/DGDZVP level, which included the comparison between theoretical and experimental optical rotation values. In addition, chemical transformations of 2 yielded suitable derivatives for NOESY and (1)H-(1)H NMR coupling constant analyses, which reinforce the stereochemical assignment. The potential affinity of 1 and 2 with (Ca(2+))(4)-hCaM in solution was measured using the fluorescent biosensor hCaM M124C-mBBr. The results showed that 1 bound to the protein with a dissociation constant (K(d)) of 0.25 ± 0.04 μM, close to that of chlorpromazine (K(d) = 0.64 ± 0.03 μM), a classical CaM inhibitor. The stoichiometry ratio of 1 to (Ca(2+))(4)-hCaM was 1:4, similar to other well-known CaM ligands.

  14. Preparation of Superhydrophobic Film on Ti Substrate and Its Anticorrosion Property.

    PubMed

    Zhu, Min; Tang, Wenchuan; Huang, Luyao; Zhang, Dawei; Du, Cuiwei; Yu, Gaohong; Chen, Ming; Chowwanonthapunya, Thee

    2017-06-08

    Superhydrophobic films were fabricated on a titanium substrate with or without anodizing by using a self-assembling method. Firstly, the pretreatments of mechanical polishing/anodizing or mechanical polishing only were conducted, respectively. Subsequently, the preparation of polydopamine film layer, deposition of nano-silver particles, and post modification of 1H,1H,2H,2H-perfluorodecanethiol were performed on the surface of the pretreated substrate. The surface morphologies, compositions, wettability, and corrosion resistance of the films were investigated with scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), water contact angle measurements, and electrochemical tests, respectively. Meanwhile, the effect of the deposition time in the silver nitrate solution on the hydrophobicity of the specimen surface was investigated. The result showed that with the increase of deposition time, the hydrophobic property enhanced gradually. The surface deposited for 7 h exhibited an optimum hydrophobic effect, which was characterized with a large water contact angle (WCA) of 154°, and the surface was rather rough and covered by a relatively uniform layer of micro-nano silver particles. The excellent hydrophobicity was attributed to a rough stratified microstructure along with the low surface energy. The electrochemical measurements showed that the existence of the superhydrophobic film can effectively enhance the corrosion resistance of Ti samples.

  15. Organic Ferroelectric-Based 1T1T Random Access Memory Cell Employing a Common Dielectric Layer Overcoming the Half-Selection Problem.

    PubMed

    Zhao, Qiang; Wang, Hanlin; Ni, Zhenjie; Liu, Jie; Zhen, Yonggang; Zhang, Xiaotao; Jiang, Lang; Li, Rongjin; Dong, Huanli; Hu, Wenping

    2017-09-01

    Organic electronics based on poly(vinylidenefluoride/trifluoroethylene) (P(VDF-TrFE)) dielectric is facing great challenges in flexible circuits. As one indispensable part of integrated circuits, there is an urgent demand for low-cost and easy-fabrication nonvolatile memory devices. A breakthrough is made on a novel ferroelectric random access memory cell (1T1T FeRAM cell) consisting of one selection transistor and one ferroelectric memory transistor in order to overcome the half-selection problem. Unlike complicated manufacturing using multiple dielectrics, this system simplifies 1T1T FeRAM cell fabrication using one common dielectric. To achieve this goal, a strategy for semiconductor/insulator (S/I) interface modulation is put forward and applied to nonhysteretic selection transistors with high performances for driving or addressing purposes. As a result, high hole mobility of 3.81 cm 2 V -1 s -1 (average) for 2,6-diphenylanthracene (DPA) and electron mobility of 0.124 cm 2 V -1 s -1 (average) for N,N'-1H,1H-perfluorobutyl dicyanoperylenecarboxydiimide (PDI-FCN 2 ) are obtained in selection transistors. In this work, we demonstrate this technology's potential for organic ferroelectric-based pixelated memory module fabrication. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Modifying Thermal Switchability of Liquid Crystalline Nanoparticles by Alkyl Ligands Variation

    PubMed Central

    Żuk, Maciej; Tupikowska, Martyna

    2018-01-01

    By coating plasmonic nanoparticles (NPs) with thermally responsive liquid crystals (LCs) it is possible to prepare reversibly reconfigurable plasmonic nanomaterials with prospective applications in optoelectronic devices. However, simple and versatile methods to precisely tailor properties of liquid-crystalline nanoparticles (LC NPs) are still required. Here, we report a new method for tuning structural properties of assemblies of nanoparticles grafted with a mixture of promesogenic and alkyl thiols, by varying design of the latter. As a model system, we used Ag and Au nanoparticles that were coated with three-ring promesogenic molecules and dodecanethiol ligand. These LC NPs self-assemble into switchable lamellar (Ag NPs) or tetragonal (Au NPs) aggregates, as determined with small angle X-ray diffraction and transmission electron microscopy. Reconfigurable assemblies of Au NPs with different unit cell symmetry (orthorombic) are formed if hexadecanethiol and 1H,1H,2H,2H-perfluorodecanethiol were used in the place of dodecanethiol; in the case of Ag NPs the use of 11-hydroxyundecanethiol promotes formation of a lamellar structure as in the reference system, although with substantially broader range of thermal stability (140 vs. 90 °C). Our results underline the importance of alkyl ligand functionalities in determining structural properties of liquid-crystalline nanoparticles, and, more generally, broaden the scope of synthetic tools available for tailoring properties of reversibly reconfigurable plasmonic nanomaterials. PMID:29518916

  17. Mechanical stability, corrosion resistance of superhydrophobic steel and repairable durability of its slippery surface.

    PubMed

    Gao, Xiaoyu; Guo, Zhiguang

    2018-02-15

    A simple way of chemical etching with H 2 SO 4 and H 2 O 2 was employed to prepare a superhydrophobic steel surface with a water contact angle of 163.5° and a sliding angle of about 0°, in addition to modification with 1H,1H,2H,2H-perfluoroalkyltriethoxysilane (FAS-13). On the basis of perfluropolyethers (PFPE) infusion, a slippery liquid-infused porous surface (SLIPS) was fabricated that had a water contact angle of 115.6° and a sliding angle of 2.27°. The prepared sample can still maintain superhydrophobicity after moving 100 cm on 1000 # sandpaper under 100 g loading via an abrasion test, while its corrosion resistance was exhibited via more positive corrosion potentials (E corr ) and lower corrosion current densities (I corr ) in electrochemical corrosion tests with various solutions. Even if superhydrophobic and slippery properties were lost in the process of long-time soaking in salt solution, the superhydrophobic steel could regain its ability and slippery surfaces also exhibited the repairable durability through retreatment. Such stable, corrosion resistant and superhydrophobic bearing steel and repairable slippery surface have potential for application in practical production and life. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Robust, heat-resistant and multifunctional superhydrophobic coating of carbon microflowers with molybdenum trioxide nanoparticles.

    PubMed

    Wu, Yang; Zhao, Meiyun; Guo, Zhiguang

    2017-11-15

    Superhydrophobic materials have triggered large interest due to their widespread applications, such as self-cleaning, corrosion resistance, anti-icing, and oil/water separation. However, suffering from weak mechanical strength, plenty of superhydrophobic materials are limited in practical application. Herein, we prepared hierarchical carbon microflowers (CMF) dispersed with molybdenum trioxide (MoO 3 ) nanoparticles (MoO 3 /CMF) via a two-step preparation method. Taking advantage of high-adhesion epoxy resin and the modification with 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PDES), the modified MoO 3 /CMF (PDES-MoO 3 /CMF) coating on various substrates shows great waterproof ability, excellent chemical stability, good mechanical durability, and self-cleaning property. More significantly, the prepared PDES-MoO 3 /CMF powder with high thermal stability (250°C) can be used for oil/water separation due to its special flower-like structure and superhydrophobicity/superoleophilicity. All of these advantages endow the superhydrophobic powders with huge potential in the practical applications. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Mussel-inspired superhydrophobic surfaces with enhanced corrosion resistance and dual-action antibacterial properties.

    PubMed

    Qian, Hongchang; Li, Minglu; Li, Zhong; Lou, Yuntian; Huang, Luyao; Zhang, Dawei; Xu, Dake; Du, Cuiwei; Lu, Lin; Gao, Jin

    2017-11-01

    In this study, a multilayer antibacterial film was assembled onto 316L stainless steel via mussel-inspired depositions of polydopamine (PDA) and silver (Ag) nanoparticles followed by post-modification with 1H, 1H, 2H, 2H-perfluorodecanethiol. The resulting surface exhibited excellent superhydrophobicity with hierarchical micro/nanostructures that were constructed by both PDA and Ag nanoparticles. The crystal structure and chemical composition of these surfaces were investigated using X-ray photoelectron spectroscopy (XPS) analysis. Potentiodynamic polarization measurements revealed that the corrosion resistance of the as-prepared surfaces were sequentially increased after each step of the fabrication process. Compared with the surface covered with only Ag nanoparticles, the superhydrophobic surfaces exhibited substantially enhanced antibacterial activity against the Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, resulting from the synergistic antibacterial actions of the superhydrophobic surface and Ag nanoparticles. The superhydrophobic surface exhibited lower cytotoxicity, compared to the surface covered with Ag nanoparticles. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Preparation of Superhydrophobic Film on Ti Substrate and Its Anticorrosion Property

    PubMed Central

    Zhu, Min; Tang, Wenchuan; Huang, Luyao; Zhang, Dawei; Du, Cuiwei; Yu, Gaohong; Chen, Ming; Chowwanonthapunya, Thee

    2017-01-01

    Superhydrophobic films were fabricated on a titanium substrate with or without anodizing by using a self-assembling method. Firstly, the pretreatments of mechanical polishing/anodizing or mechanical polishing only were conducted, respectively. Subsequently, the preparation of polydopamine film layer, deposition of nano-silver particles, and post modification of 1H,1H,2H,2H-perfluorodecanethiol were performed on the surface of the pretreated substrate. The surface morphologies, compositions, wettability, and corrosion resistance of the films were investigated with scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), water contact angle measurements, and electrochemical tests, respectively. Meanwhile, the effect of the deposition time in the silver nitrate solution on the hydrophobicity of the specimen surface was investigated. The result showed that with the increase of deposition time, the hydrophobic property enhanced gradually. The surface deposited for 7 h exhibited an optimum hydrophobic effect, which was characterized with a large water contact angle (WCA) of 154°, and the surface was rather rough and covered by a relatively uniform layer of micro-nano silver particles. The excellent hydrophobicity was attributed to a rough stratified microstructure along with the low surface energy. The electrochemical measurements showed that the existence of the superhydrophobic film can effectively enhance the corrosion resistance of Ti samples. PMID:28772987

  1. Super-Hydrophobic/Icephobic Coatings Based on Silica Nanoparticles Modified by Self-Assembled Monolayers.

    PubMed

    Liu, Junpeng; Janjua, Zaid A; Roe, Martin; Xu, Fang; Turnbull, Barbara; Choi, Kwing-So; Hou, Xianghui

    2016-12-02

    A super-hydrophobic surface has been obtained from nanocomposite materials based on silica nanoparticles and self-assembled monolayers of 1 H ,1 H ,2 H ,2 H -perfluorooctyltriethoxysilane (POTS) using spin coating and chemical vapor deposition methods. Scanning electron microscope images reveal the porous structure of the silica nanoparticles, which can trap small-scale air pockets. An average water contact angle of 163° and bouncing off of incoming water droplets suggest that a super-hydrophobic surface has been obtained based on the silica nanoparticles and POTS coating. The monitored water droplet icing test results show that icing is significantly delayed by silica-based nano-coatings compared with bare substrates and commercial icephobic products. Ice adhesion test results show that the ice adhesion strength is reduced remarkably by silica-based nano-coatings. The bouncing phenomenon of water droplets, the icing delay performance and the lower ice adhesion strength suggest that the super-hydrophobic coatings based on a combination of silica and POTS also show icephobicity. An erosion test rig based on pressurized pneumatic water impinging impact was used to evaluate the durability of the super-hydrophobic/icephobic coatings. The results show that durable coatings have been obtained, although improvement will be needed in future work aiming for applications in aerospace.

  2. Conformational analyses of 2,3-dihydroxypropanoic acid as a function of solvent and ionization state as determined by NMR spectroscopy.

    PubMed

    Drake, Michael D; Harsha, Alex K; Terterov, Sergei; Roberts, John D

    2006-03-01

    Vicinal (1)H--(1)H coupling constants were used to determine the conformational preferences of 2,3-dihydroxypropanoic acid (1) (DL-glyceric acid) in various solvents and its different carboxyl ionization states. The stereospecific assignments of J(12) and J(13) were confirmed through the point-group substitution of the C-3 hydrogen with deuterium, yielding rac-(2SR,3RS)-[3-(2)H]-1, and the observation of only J(13) in the (1)H NMR spectra. While hydrogen bonding and steric strain may be expected to drive the conformational equilibrium, their role is overshadowed by a profound gauche effect between the vicinal hydroxyl groups that mimics other substituted ethanes, such as 1,2-ethanediol and 1,2-difluoroethane. At low pH, the conformational equilibrium is heavily weighted toward the gauche-hydroxyl rotamers with a range of 81% in DMSO-d(6) to 92% in tert-butyl alcohol-d(10). At high pH, the equilibrium exhibits a larger dependence upon the polarity and solvating capability of the medium, although the gauche effect still dominates in D(2)O, 1,4-dioxane-d(8), methanol-d(4), and ethanol-d(6) (96, 89, 85, and 83% gauche-hydroxyls respectively). The observed preference for the gauche-hydroxyl rotamers is believed to stem primarily from hyperconjugative sigma(C--H) --> sigma*(C--OH) interactions.

  3. NMR spin-rotation relaxation and diffusion of methane

    NASA Astrophysics Data System (ADS)

    Singer, P. M.; Asthagiri, D.; Chapman, W. G.; Hirasaki, G. J.

    2018-05-01

    The translational diffusion-coefficient and the spin-rotation contribution to the 1H NMR relaxation rate for methane (CH4) are investigated using MD (molecular dynamics) simulations, over a wide range of densities and temperatures, spanning the liquid, supercritical, and gas phases. The simulated diffusion-coefficients agree well with measurements, without any adjustable parameters in the interpretation of the simulations. A minimization technique is developed to compute the angular velocity for non-rigid spherical molecules, which is used to simulate the autocorrelation function for spin-rotation interactions. With increasing diffusivity, the autocorrelation function shows increasing deviations from the single-exponential decay predicted by the Langevin theory for rigid spheres, and the deviations are quantified using inverse Laplace transforms. The 1H spin-rotation relaxation rate derived from the autocorrelation function using the "kinetic model" agrees well with measurements in the supercritical/gas phase, while the relaxation rate derived using the "diffusion model" agrees well with measurements in the liquid phase. 1H spin-rotation relaxation is shown to dominate over the MD-simulated 1H-1H dipole-dipole relaxation at high diffusivity, while the opposite is found at low diffusivity. At high diffusivity, the simulated spin-rotation correlation time agrees with the kinetic collision time for gases, which is used to derive a new expression for 1H spin-rotation relaxation, without any adjustable parameters.

  4. CFA-1: the first chiral metal-organic framework containing Kuratowski-type secondary building units.

    PubMed

    Schmieder, Phillip; Denysenko, Dmytro; Grzywa, Maciej; Baumgärtner, Benjamin; Senkovska, Irena; Kaskel, Stefan; Sastre, German; van Wüllen, Leo; Volkmer, Dirk

    2013-08-14

    The novel homochiral metal-organic framework CFA-1 (Coordination Framework Augsburg-1), [Zn5(OAc)4(bibta)3], containing the achiral linker {H2-bibta = 1H,1'H-5,5'-bibenzo[d][1,2,3]triazole}, has been synthesised. The reaction of H2-bibta and Zn(OAc)2·2H2O in N-methylformamide (NMF) (90 °C, 3 d) yields CFA-1 as trigonal prismatic single crystals. CFA-1 serves as a convenient precursor for the synthesis of isostructural frameworks with redox-active metal centres, which is demonstrated by the postsynthetic exchange of Zn(2+) by Co(2+) ions. The framework is robust to solvent removal and has been structurally characterized by synchrotron single-crystal X-ray diffraction and solid state NMR measurements ((13)C MAS- and (1)H MAS-NMR at 10 kHz). Results from MAS-NMR and IR spectroscopy studies are corroborated by cluster and periodic DFT calculations performed on CFA-1 cluster fragments.

  5. Effect of chemical and physical heterogeneities on colloid-facilitated cesium transport

    NASA Astrophysics Data System (ADS)

    Rod, Kenton; Um, Wooyong; Chun, Jaehun; Wu, Ning; Yin, Xialong; Wang, Guohui; Neeves, Keith

    2018-06-01

    A set of column experiments was conducted to investigate the chemical and physical heterogeneity effect on colloid facilitated transport under slow pore velocity conditions. Pore velocities were kept below 100 cm d-1 for all experiments. Glass beads were packed into columns establishing four different conditions: 1) homogeneous, 2) mixed physical heterogeneity, 3) sequentially layered physical heterogeneity, and 4) chemical heterogeneity. The homogeneous column was packed with glass beads (diameter 500-600 μm), and physical heterogeneities were created by sequential layering or mixing two sizes of glass bead (500-600 μm and 300-400 μm). A chemical heterogeneity was created using 25% of the glass beads coated with hydrophobic molecules (1H-1H-2H-2H-perfluorooctyltrichlorosilane) mixed with 75% pristine glass beads (all 500-600 μm). Input solution with 0.5 mM CsI and 50 mg L-1 colloids (1-μm diameter SiO2) was pulsed into columns under saturated conditions. The physical heterogeneity in the packed glass beads retarded the transport of colloids compared to homogeneous (R = 25.0), but showed only slight differences between sequentially layered (R = 60.7) and mixed heterogeneity(R = 62.4). The column with the chemical, hydrophobic/hydrophilic, heterogeneity removed most of the colloids from the input solution. All column conditions stripped Cs from colloids onto the column matrix of packed glass beads.

  6. Multiple-step relayed correlation spectroscopy: sequential resonance assignments in oligosaccharides.

    PubMed Central

    Homans, S W; Dwek, R A; Fernandes, D L; Rademacher, T W

    1984-01-01

    A general property of the high-resolution proton NMR spectra of oligosaccharides is the appearance of low-field well-resolved resonances corresponding to the anomeric (H1) and H2 protons. The remaining skeletal protons resonate in the region 3-4 ppm, giving rise to an envelope of poorly resolved resonances. Assignments can be made from the H1 and H2 protons to their J-coupled neighbors (H2 and H3) within this main envelope by using 1H-1H correlated spectroscopy. However, the tight coupling (J congruent to delta) between further protons results in poor spectral dispersion with consequent assignment ambiguities. We describe here three-step two-dimensional relayed correlation spectroscopy and show how it can be used to correlate the resolved anomeric (H1) and H2 protons with remote (H4, H5) protons directly through a linear network of couplings using sequential magnetization transfer around the oligosaccharide rings. Resonance assignments are then obtained by inspection of cross-peaks that appear in well-resolved regions of the two-dimensional spectrum. This offers a general solution to the assignment problem in oligosaccharides and, importantly, these assignments will subsequently allow for the three-dimensional solution conformation to be determined by using one-dimensional and two-dimensional nuclear Overhauser experiments. PMID:6593701

  7. Functionalized three-dimensional graphene sponges for highly efficient crude and diesel oil adsorption.

    PubMed

    Bagoole, Oscar; Rahman, Md Mahfuzur; Shah, Sohail; Hong, Haiping; Chen, Hang; Al Ghaferi, Amal; Younes, Hammad

    2018-06-02

    Modified Hummer's method has been used in this study to synthesize graphene oxide (GO) solution that was utilized for the fabrication of three-dimensional (3D) graphene sponges and their subsequent functionalization through a low-cost and facile vapor-based surface enhancement approach. The functionalized 3D-graphene sponge is an excellent absorbent, which can remove more than 3300 wt.% of crude oil (calculated with respect to the original sorbent mass). The functionalization of the obtained graphene sponges with trichloro (1H,1H,2H,2H-perfluorooctyl)silane enhanced their wettability properties due to the super-hydrophobic nature of the resulting materials characterized by the contact angles in water greater than 150°. Furthermore, their elastic compression modulus (estimated by conducting a series of compression tests) was about 22.3 kPa. The equilibrium modeling of the oil removal process, which was performed by plotting Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherms, confirmed the properties of the fabricated 3D graphene sponges as exceptional absorbents for crude and diesel oil, which could be attributed to the oleophilic nature of graphene. Moreover, the obtained 3D graphene sponges could be regenerated via heat treatment, which was conducted to release the adsorbed species. After five adsorption-desorption cycles, the sorption capacity of the produced 3D graphene sponges towards crude oil reached 95% of the initial value.

  8. Structural studies of a polysaccharide from Vibrio parahaemolyticus strain AN-16000.

    PubMed

    Fontana, Carolina; Zaccheus, Mona; Weintraub, Andrej; Ansaruzzaman, Mohammad; Widmalm, Göran

    2016-09-02

    The structure of a polysaccharide from Vibrio parahaemolyticus strain AN-16000 has been investigated. The sugar and absolute configuration analysis revealed d-Glc, d-GalN, d-QuiN and l-FucN as major components. The PS was subjected to dephosphorylation with aqueous 40% HF to obtain an oligosaccharide that was analyzed by (1)H and (13)C NMR spectroscopy. The HR-MS spectrum of the oligosaccharide revealed a pentasaccharide composed of two Glc residues, one QuiNAc and one GalNAc, one FucNAc, as well as a glycerol moiety. The structure of the PS was determined using (1)H, (13)C, (15)N and (31)P NMR spectroscopy; inter-residue correlations were identified by (1)H,(13)C-heteronuclear multiple-bond correlation, (1)H,(1)H-NOESY and (1)H,(31)P-hetero-TOCSY experiments. The PS backbone has the following teichoic acid-like structure: →3)-d-Gro-(1-P-6)-β-d-Glcp-(1→4)-α-l-FucpNAc-(1→3)-β-d-QuipNAc-(1→ with a side-chain consisting of α-d-Glcp-(1→6)-α-d-GalpNAc-(1→ linked to the O3 position of the FucNAc residue. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Host-guest chemistry of dendrimer-drug complexes: 7. Formation of stable inclusions between acetylated dendrimers and drugs bearing multiple charges.

    PubMed

    Fang, Min; Zhang, Jiahai; Wu, Qinglin; Xu, Tongwen; Cheng, Yiyun

    2012-03-15

    Drug molecules bearing multiple charges usually form precipitates with cationic dendrimers, which presents a challenge during the preparation of dendrimer inclusions for these drugs. In the present study, fully acetylated polyamidoamine (PAMAM) dendrimers were proposed as stable vehicles for drug molecules bearing two negative charges such as Congo red and indocyanine green. NMR techniques including (1)H NMR and (1)H-(1)H NOESY were used to characterize the host-guest chemistry of acetylated dendrimer and these guest molecules. The cationic PAMAM dendrimer was found to form a precipitate with Congo red and indocyanine green, but the acetylated one avoided the formation of cross-linking structures in aqueous solutions. NOESY studies revealed the encapsulation of Congo red and indocyanine green within the interior cavities of PAMAM dendrimers at mild acidic conditions and acetylated dendrimers show much stronger ability to encapsulate the guest molecules than cationic ones. Also, UV-vis-NIR studies suggest that acetylated dendrimers significantly improve the photostability of indocyanine green and prevent the formation of indocyanine green J-aggregates in aqueous solutions. The present study provides a new insight into dendrimer-based host-guest systems, especially for those guest molecules bearing multiple charges. © 2012 American Chemical Society

  10. Comprehensive Metabolite Identification Strategy Using Multiple Two-Dimensional NMR Spectra of a Complex Mixture Implemented in the COLMARm Web Server

    SciTech Connect

    Bingol, Kerem; Li, Da-Wei; Zhang, Bo

    Identification of metabolites in complex mixtures represents a key step in metabolomics. A new strategy is introduced, which is implemented in a new public web server, COLMARm, that permits the co-analysis of up to three 2D NMR spectra, namely 13C-1H HSQC, 1H-1H TOCSY, and 13C-1H HSQC-TOCSY for the comprehensive, accurate, and efficient performance of this task. The highly versatile and interactive nature of COLMARm permits its application to a wide range of metabolomics samples independent of the magnetic field. Database query is performed using the HSQC spectrum and the top metabolite hits are then validated against the TOCSY-type experiment(s) bymore » superimposing the expected cross-peaks on the mixture spectrum. In this way the user can directly accept or reject candidate metabolites by taking advantage of the complementary spectral information offered by these experiments and their different sensitivities. The power of COLMARm is demonstrated for a human serum sample uncovering the existence of 14 metabolites that hitherto were not identified by NMR.« less

  11. Methoxyflavones from New Lingzhi Medicinal Mushroom, Ganoderma lingzhi (Agaricomycetes).

    PubMed

    Shimizu, Kuniyoshi; Amen, Yhiya M; Kaifuchi, Satoru

    2016-01-01

    Ganoderma lingzhi is one of the most famous medicinal fungi in the world. It has been used in folk medicine, especially in East Asian countries. It is also a white-rot fungus with strong wood degradation ability, especially against lignin. Different classes of bioactive natural products have been reported in Ganoderma, including triterpenes, polysaccharides, sterols, and peptides. The triterpenes and polysaccharides are the primary bioactive compounds of Ganoderma. We report for the first time the presence of 3 methoxyflavones as minor constituents in G. linghzi. The 3 compounds were identified based on different spectroscopic techniques, including 1- and 2-dimensional nuclear magnetic resonance (1H-1H correlation spectroscopy, heteronuclear single quantum coherence, and heteronuclear multiple bond correlation) and mass spectrometry (high-resolution electrospray ionization mass spectrometry). Our report provides an approach to a possible biosynthetic pathway for biosynthetic genes in the mushrooms. Another great possibility is that these compounds may exist or be formed through degradation of the components in the woody substrate, such as lignin, and then subsequently translocate to the fruiting bodies.

  12. Superhydrophobicity of electrospray-synthesized fluorinated silica layers.

    PubMed

    Kim, Eun-Kyeong; Lee, Chul-Sung; Kim, Sang Sub

    2012-02-15

    The preparation of superhydrophobic SiO(2) layers through a combination of a nanoscale surface roughness and a fluorination treatment is reported. Electrospraying SiO(2) precursor solutions that had been prepared by a sol-gel chemical route produced very rough SiO(2) layers. Subsequent fluorination treatment with a solution containing trichloro(1H,1H,2H,2H-perfluorooctyl)silane resulted in highly rough, fluorinated SiO(2) layers. The fluorinated rough SiO(2) layers exhibited excellent repellency toward various liquid droplets. In particular, water repellency of 168° was observed. On the bases of Cassie-Baxter and Young-Dupre equations, the surface fraction and the work of adhesion of the rough, fluorinated SiO(2) layers were respectively estimated. In light of the durability in water, ultraviolet resistance, and thermal stability, the superhydrophobic SiO(2) layers prepared in this work hold promise in a range of practical applications. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. Measurements of gas hydrate formation probability distributions on a quasi-free water droplet

    NASA Astrophysics Data System (ADS)

    Maeda, Nobuo

    2014-06-01

    A High Pressure Automated Lag Time Apparatus (HP-ALTA) can measure gas hydrate formation probability distributions from water in a glass sample cell. In an HP-ALTA gas hydrate formation originates near the edges of the sample cell and gas hydrate films subsequently grow across the water-guest gas interface. It would ideally be desirable to be able to measure gas hydrate formation probability distributions of a single water droplet or mist that is freely levitating in a guest gas, but this is technically challenging. The next best option is to let a water droplet sit on top of a denser, immiscible, inert, and wall-wetting hydrophobic liquid to avoid contact of a water droplet with the solid walls. Here we report the development of a second generation HP-ALTA which can measure gas hydrate formation probability distributions of a water droplet which sits on a perfluorocarbon oil in a container that is coated with 1H,1H,2H,2H-Perfluorodecyltriethoxysilane. It was found that the gas hydrate formation probability distributions of such a quasi-free water droplet were significantly lower than those of water in a glass sample cell.

  14. ARTSY-J: Convenient and precise measurement of 3JHNHα couplings in medium-size proteins from TROSY-HSQC spectra

    NASA Astrophysics Data System (ADS)

    Roche, Julien; Ying, Jinfa; Shen, Yang; Torchia, Dennis A.; Bax, Ad

    2016-07-01

    A new and convenient method, named ARTSY-J, is introduced that permits extraction of the 3JHNHα couplings in proteins from the relative intensities in a pair of 15N-1H TROSY-HSQC spectra. The pulse scheme includes 3JHNHα dephasing of the narrower TROSY 1HN-{15N} doublet component during a delay, integrated into the regular two-dimensional TROSY-HSQC pulse scheme, and compares the obtained intensity with a reference spectrum where 3JHNHα dephasing is suppressed. The effect of passive 1Hα spin flips downscales the apparent 3JHNHα coupling by a uniform factor that depends approximately linearly on both the duration of the 3JHNHα dephasing delay and the 1H-1H cross relaxation rate. Using such a correction factor, which accounts for the effects of both inhomogeneity of the radiofrequency field and 1Hα spin flips, agreement between prior and newly measured values for the small model protein GB3 is better than 0.3 Hz. Measurement for the HIV-1 protease homodimer (22 kDa) yields 3JHNHα values that agree to better than 0.7 Hz with predictions made on the basis of a previously parameterized Karplus equation. Although for Gly residues the two individual 3JHNHα couplings cannot be extracted from a single set of ARTSY-J spectra, the measurement provides valuable ϕ angle information.

  15. Characteristics of deacetylation and depolymerization of β-chitin from jumbo squid (Dosidicus gigas) pens.

    PubMed

    Jung, Jooyeoun; Zhao, Yanyun

    2011-09-27

    This study evaluated the deacetylation characteristics of β-chitin from jumbo squid (Dosidicus gigas) pens by using strongly alkaline solutions of NaOH or KOH. Taguchi design was employed to investigate the effect of reagent concentration, temperature, time, and treatment step on molecular mass (MM) and degree of deacetylation (DDA) of the chitosan obtained. The optimal treatment conditions for achieving high MM and DDA of chitosan were identified as: 40% NaOH at 90°C for 6h with three separate steps (2h+2h+2h) or 50% NaOH at 90°C for 6h with one step, or 50% KOH at 90°C for 4h with three steps (1h+1h+2h) or 6h with one step. The most important factor affecting DDA and MM was temperature and time, respectively. The chitosan obtained was then further depolymerized by cellulase or lysozyme with cellulase giving a higher degradation ratio, lower relative viscosity, and a larger amount of reducing-end formations than that of lysozyme due to its higher susceptibility. This study demonstrated that jumbo squid pens are a good source of materials to produce β-chitosan with high DDA and a wide range of MM for various potential applications. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Desalination by Membrane Distillation using Electrospun Polyamide Fiber Membranes with Surface Fluorination by Chemical Vapor Deposition.

    PubMed

    Guo, Fei; Servi, Amelia; Liu, Andong; Gleason, Karen K; Rutledge, Gregory C

    2015-04-22

    Fibrous membranes of poly(trimethyl hexamethylene terephthalamide) (PA6(3)T) were fabricated by electrospinning and rendered hydrophobic by applying a conformal coating of poly(1H,1H,2H,2H-perfluorodecyl acrylate) (PPFDA) using initiated chemical vapor deposition (iCVD). A set of iCVD-treated electrospun PA6(3)T fiber membranes with fiber diameters ranging from 0.25 to 1.8 μm were tested for desalination using the air gap membrane distillation configuration. Permeate fluxes of 2-11 kg/m2/h were observed for temperature differentials of 20-45 °C between the feed stream and condenser plate, with rejections in excess of 99.98%. The liquid entry pressure was observed to increase dramatically, from 15 to 373 kPa with reduction in fiber diameter. Contrary to expectation, for a given feed temperature the permeate flux was observed to increase for membranes of decreasing fiber diameter. The results for permeate flux and salt rejection show that it is possible to construct membranes for membrane distillation even from intrinsically hydrophilic materials after surface modification by iCVD and that the fiber diameter is shown to play an important role on the membrane distillation performance in terms of permeate flux, salt rejection, and liquid entry pressure.

  17. Effect of fibre treatment using fluorosilane on Sansevieria Trifasciata/Polypropylene composite

    NASA Astrophysics Data System (ADS)

    Aref, Yanzur Mohd; Baharum, Azizah

    2018-04-01

    Recently, there is an increasing interest in the development of wood-plastic composites (WPC) due to their advantages such as wide availability, low cost, environment friendliness and sustainability. However, some major factors limiting the large scales production of WPC including the tendency of natural fibres to absorb water and the poor compatibility between fibre and matrix. In this study, we investigated the effectiveness of natural fibre treatment using fluorosilane in imparting hydrophobicity to the polypropylene (PP) matrix composite reinforced with Sansevieria Trifasciata (ST) fibres. ST fibres are subjected to silane treatment with 1H,1H,2H,2H-perfluorooctyltriethoxsysilane (POTS) at 1, 3 and 5% for a period of 2 hours. Influence of POTS treatment on the physical and mechanical properties of composites was studied to determine the optimum condition of silane treatment. The water contact angle (WCA) of WPC increased after POTS treatment where the highest value of 115° was shown by 3% POTS treated ST/PP composite. Based on mechanical properties results, incorporation of POTS treated ST fibre improves the mechanical properties with the enhancement of flexural and impact strength. The treatment with 3% POTS revealed statistically higher flexural strength and modulus compared to 1 and 5%. The water absorption test of ST/PP composites also gives the best result for 3% POTS treatment with 20.90% water uptake.

  18. Complement Factor H and Simian Virus 40 bind the GM1 ganglioside in distinct conformations.

    PubMed

    Blaum, Bärbel S; Frank, Martin; Walker, Ross C; Neu, Ursula; Stehle, Thilo

    2016-05-01

    Mammalian cell surfaces are decorated with a variety of glycan chains that orchestrate development and defense and are exploited by pathogens for cellular attachment and entry. While glycosidic linkages are, in principle, flexible, the conformational space that a given glycan can sample is subject to spatial and electrostatic restrictions imposed by its overall chemical structure. Here, we show how the glycan moiety of the GM1 ganglioside, a branched, monosialylated pentasaccharide that serves as a ligand for various proteins, undergoes differential conformational selection in its interactions with different lectins. Using STD NMR and X-ray crystallography, we found that the innate immune regulator complement Factor H (FH) binds a previously not reported GM1 conformation that is not compatible with the GM1-binding sites of other structurally characterized GM1-binding lectins such as the Simian Virus 40 (SV40) capsid. Molecular dynamics simulations of the free glycan in explicit solvent on the 10 μs timescale reveal that the FH-bound conformation nevertheless corresponds to a minimum in the Gibbs free energy plot. In contrast to the GM1 conformation recognized by SV40, the FH-bound GM1 conformation is associated with poor NOE restraints, explaining how it escaped(1)H-(1)H NOE-restrained modeling in the past and highlighting the necessity for ensemble representations of glycan structures. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Spatially controlled immobilisation of biomolecules: A complete approach in green chemistry

    NASA Astrophysics Data System (ADS)

    Grinenval, Eva; Nonglaton, Guillaume; Vinet, Françoise

    2014-01-01

    The development of 'green' sensors is a challenging task in the field of biomolecule sensing, for example in the detection of cardiac troponin-I (cTnI). In the present work a complete approach in green chemistry was developed to create chemically active patterns for the immobilisation of biological probes. This key technology is discussed on the basis of the twelve green chemistry principles, and is a combination of surface patterning by spotting and surface chemistries modified by molecular vapour deposition. The (1H,1H,2H,2H)-perfluorodecyltrichlorosilane (FDTS) was used as a novel anti-adsorption layer while the 3,4-epoxybutyltrimethoxysilane (EBTMOS) was used to immobilise probes. Oligonucleotides and the anti-cTnI antibody were studied. The spatially controlled immobilisation of probes was characterised by fluorescence. The demonstrated surface modification has broad applications in areas such as diagnostics and bio-chemical sensing. Moreover, the environmental impacts of surface patterning and surface chemistry were discussed from a 'greenness' point of view.

  20. Intramolecular Hydrogen Bonding in Benzoxazines: When Structural Design Becomes Functional.

    PubMed

    Froimowicz, Pablo; Zhang, Kan; Ishida, Hatsuo

    2016-02-18

    The future evolution of benzoxazines and polybenzoxazines as advanced molecular, structural, functional, engineering, and newly commercial materials depends to a great extent on a deeper and more fundamental understanding at the molecular level. In this contribution, the field of benzoxazines is briefly introduced along with a more detailed review of ortho-amide-functional benzoxazines, which are the main subjects of this article. Provided in this article are the detailed and solid scientific evidences of intramolecular five-membered-ring hydrogen bonding, which is supposed to be responsible for the unique and characteristic features exhibited by this ever-growing family of ortho-functionalized benzoxazines. One-dimensional (1D) (1)H NMR spectroscopy was used to study various concentrations of benzoxazines in various solvents with different hydrogen-bonding capability and at various temperatures to investigate in detail the nature of hydrogen bonding in both ortho-amide-functionalized benzoxazine and its para counterpart. These materials were further investigated by two-dimensional (2D) (1)H-(1)H nuclear Overhauser effect spectroscopy (NOESY) to verify and support the conclusions derived during the 1D (1)H NMR experiments. Only highly purified single-crystal benzoxazine samples have been used for this study to avoid additional interactions caused by any impurities. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.