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Sample records for 13c high-resolution solid-state

  1. High resolution 13C-detected solid-state NMR spectroscopy of a deuterated protein

    PubMed Central

    Tang, Ming; Comellas, Gemma; Mueller, Leonard J.

    2011-01-01

    High resolution 13C-detected solid-state NMR spectra of the deuterated beta-1 immunoglobulin binding domain of the protein G (GB1) have been collected to show that all 15N, 13C′, 13Cα and 13Cβ sites are resolved in 13C–13C and 15N–13C spectra, with significant improvement in T2 relaxation times and resolution at high magnetic field (750 MHz). The comparison of echo T2 values between deuterated and protonated GB1 at various spinning rates and under different decoupling schemes indicates that 13Cα T2′ times increase by almost a factor of two upon deuteration at all spinning rates and under moderate decoupling strength, and thus the deuteration enables application of scalar-based correlation experiments that are challenging from the standpoint of transverse relaxation, with moderate proton decoupling. Additionally, deuteration in large proteins is a useful strategy to selectively detect polar residues that are often important for protein function and protein–protein interactions. PMID:20803233

  2. Detection of tannins in modern and fossil barks and in plant residues by high-resolution solid-state 13C nuclear magnetic resonance

    USGS Publications Warehouse

    Wilson, M.A.; Hatcher, P.G.

    1988-01-01

    Bark samples isolated from brown coal deposits in Victoria, Australia, and buried wood from Rhizophora mangle have been studies by high-resolution solid-state nuclear magnetic resonance (NMR) techniques. Dipolar dephasing 13C NMR appears to be a useful method of detecting the presence of tannins in geochemical samples including barks, buried woods, peats and leaf litter. It is shown that tannins are selectively preserved in bark during coalification to the brown coal stage. ?? 1988.

  3. Investigation of gamma-irradiated vegetable seeds with high-resolution solid-state 13C NMR.

    PubMed

    Bardet, Michel; Maron, Sébastien; Foray, Marie Françoise; Berger, Maurice; Guillermo, Armel

    2004-04-01

    13C solid-state NMR was used to investigate the effects of gamma radiation on vegetable seeds, Pisum sativum and Latuca sativa, at absorbed doses that inhibit their germination. By combining single-pulse excitation and cross-polarization experiments under magic angle spinning, both liquid and solid domains of seeds can be characterized. We showed that the liquid domains, mostly made of triacylglycerols (TAG), of vegetable seeds are not sensitive to radiation. The main structural changes have been observed in the embryonic axes of seeds when the seeds are water-imbibed before irradiation. These results rule out a starting hypothesis concerning the potential role of TAG contained in oil bodies as a potential source of aldehydes that could further react with DNA moiety.

  4. Microscopic structure of heterogeneous lipid-based formulations revealed by 13C high-resolution solid-state and 1H PFG NMR methods.

    PubMed

    Guillermo, Armel; Gerbaud, Guillaume; Bardet, Michel

    2010-03-01

    Lipid-based formulations such as lip glosses that are very alike on the base of their components may have significant differences in their expected macroscopic properties as cosmetics. To differentiate such formulations, high-resolution (13)C NMR was performed under magic angle spinning to investigate the properties at both molecular and microscopic levels. Temperature studies were carried out and no polymorphism in the solid domains could be evidenced after the thermal treatment performed for obtaining the commercial lip glosses. (13)C NMR spectra also showed that some waxes remain partially solubilized in the oils of formulations. The microscopic structure of the wax-oil liquid domains was worked out on the basis of restricted diffusion properties obtained with proton pulsed-field gradient NMR. Changing a single wax component, in two identical formulations, yields significant morphological differences. In the first one the liquid phase appears as a continuum whereas in the second one, the liquid phase is fractionated into micrometric droplets.

  5. High-resolution solid-state 13C NMR spectroscopy of the paramagnetic metal-organic frameworks, STAM-1 and HKUST-1.

    PubMed

    Dawson, Daniel M; Jamieson, Lauren E; Mohideen, M Infas H; McKinlay, Alistair C; Smellie, Iain A; Cadou, Romain; Keddie, Neil S; Morris, Russell E; Ashbrook, Sharon E

    2013-01-21

    Solid-state (13)C magic-angle spinning (MAS) NMR spectroscopy is used to investigate the structure of the Cu(II)-based metal-organic frameworks (MOFs), HKUST-1 and STAM-1, and the structural changes occurring within these MOFs upon activation (dehydration). NMR spectroscopy is an attractive technique for the investigation of these materials, owing to its high sensitivity to local structure, without any requirement for longer-range order. However, interactions between nuclei and unpaired electrons in paramagnetic systems (e.g., Cu(II)-based MOFs) pose a considerable challenge, not only for spectral acquisition, but also in the assignment and interpretation of the spectral resonances. Here, we exploit the rapid T(1) relaxation of these materials to obtain (13)C NMR spectra using a spin-echo pulse sequence at natural abundance levels, and employ frequency-stepped acquisition to ensure uniform excitation of resonances over a wide frequency range. We then utilise selective (13)C isotopic labelling of the organic linker molecules to enable an unambiguous assignment of NMR spectra of both MOFs for the first time. We show that the monomethylated linker can be recovered from STAM-1 intact, demonstrating not only the interesting use of this MOF as a protecting group, but also the ability (for both STAM-1 and HKUST-1) to recover isotopically-enriched linkers, thereby reducing significantly the overall cost of the approach.

  6. Solid-state {sup 19}F and {sup 13}C NMR of room temperature fluorinated graphite and samples thermally treated under fluorine: Low-field and high-resolution studies

    SciTech Connect

    Giraudet, J.; Dubois, M.; Guerin, K.; Pinheiro, J.P.; Hamwi, A.; Stone, W.E.E.; Pirotte, P.; Masin, F. . E-mail: fmasin@ulb.ac.be

    2005-04-15

    Room temperature graphite fluorides consisting of raw material and samples post-treated in pure fluorine atmosphere in the temperature range 100-500 deg. C have been studied by solid-state NMR. Several NMR approaches have been used, both high and low-field {sup 19}F, {sup 19}F MAS and {sup 13}C MAS with {sup 19}F to {sup 13}C cross polarization. The modifications, in the graphitic lattice, of the catalytic iodine fluorides products have been examined. A transformation of the C-F bond character from semi-ionic to covalent has been found to occur at a post-treatment temperature close to 400 deg. C. It is shown that covalency increases with temperature.

  7. Functional groups identified by solid state 13C NMR spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Animal manure is generally high in organic matter intensity so it is well suitable for 13C nuclear magnetic resonance (NMR) analysis. Solid-state 13C NMR techniques used in characterizing organic matter and its components include, but are not limited to, cross-polarization /magic angle spinning (CP...

  8. Applications of high-resolution solid-state NMR spectroscopy in food science.

    PubMed

    Bertocchi, Fabio; Paci, Maurizio

    2008-10-22

    The principal applications of high-resolution solid-state NMR spectroscopy, in the field of food science, are reviewed, after a short general introduction, mainly focusing on the potential of these investigations, which are, today, routine tools for resolving technological problems. Selected examples of the applications in the field of food science of high-resolution solid-state NMR spectroscopy both in (13)C and in (1)H NMR particularly illustrative of the results obtainable are reported in some detail.

  9. Labeling strategies for 13C-detected aligned-sample solid-state NMR of proteins

    NASA Astrophysics Data System (ADS)

    Filipp, Fabian V.; Sinha, Neeraj; Jairam, Lena; Bradley, Joel; Opella, Stanley J.

    2009-12-01

    13C-detected solid-state NMR experiments have substantially higher sensitivity than the corresponding 15N-detected experiments on stationary, aligned samples of isotopically labeled proteins. Several methods for tailoring the isotopic labeling are described that result in spatially isolated 13C sites so that dipole-dipole couplings among the 13C are minimized, thus eliminating the need for homonuclear 13C- 13C decoupling in either indirect or direct dimensions of one- or multi-dimensional NMR experiments that employ 13C detection. The optimal percentage for random fractional 13C labeling is between 25% and 35%. Specifically labeled glycerol and glucose can be used at the carbon sources to tailor the isotopic labeling, and the choice depends on the resonances of interest for a particular study. For investigations of the protein backbone, growth of the bacteria on [2- 13C]-glucose-containing media was found to be most effective.

  10. Dipolar-coupling-mediated total correlation spectroscopy in solid-state 13C NMR: Selection of individual 13C- 13C dipolar interactions

    NASA Astrophysics Data System (ADS)

    Spano, Justin; Wi, Sungsool

    2010-06-01

    Herein is described a useful approach in solid-state NMR, for selecting homonuclear 13C- 13C spin pairs in a multiple- 13C homonuclear dipolar coupled spin system. This method builds upon the zero-quantum (ZQ) dipolar recoupling method introduced by Levitt and coworkers (Marin-Montesinos et al., 2006 [30]) by extending the originally introduced one-dimensional (1D) experiment into a two-dimensional (2D) method with selective irradiation scheme, while moving the 13C- 13C mixing scheme from the transverse to the longitudinal mode, together with a dramatic improvement in the proton decoupling efficiency. Selective spin-pair recoupling experiments incorporating Gaussian and cosine-modulated Gaussian pulses for inverting specific spins were performed, demonstrating the ability to detect informative, simplified/individualized, long-range 13C- 13C homonuclear dipolar coupling interactions more accurately by removing less informative, stronger, short-range 13C- 13C interactions from 2D correlation spectra. The capability of this new approach was demonstrated experimentally on uniformly 13C-labeled Glutamine and a tripeptide sample, GAL.

  11. Solid-state /sup 13/C NMR and X-ray diffraction of dermatan sulfate

    SciTech Connect

    Winter, W.T.; Taylor, M.G.; Stevens, E.S.; Morris, E.R.; Rees, D.A.

    1986-05-29

    Dermatan sulfate in the solid state has been studied by /sup 13/C CP/MAS nmr and X-ray diffraction in order to establish the ring conformation of the L-iduronate moiety. The solid state nmr spectrum is similar to the solution spectrum obtained previously, indicating that a ring conformation at least approximating to /sup 1/C/sub 4/ predominates in the solid state. X-ray powder diffraction data from the same sample indicate the presence of the 8-fold helix form previously observed by fiber diffraction, and interpreted in terms of a /sup 4/C/sub 1/ ring form. A likely explanation of the results is that a distorted /sup 1/C/sub 4/ L-iduronate ring conformation, not considered in the initial X-ray analysis, may emerge to provide a satisfactory interpretation of all available physical-chemical data.

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

    PubMed

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

    2015-01-01

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

  13. (13)C NMR assignments of regenerated cellulose from solid-state 2D NMR spectroscopy.

    PubMed

    Idström, Alexander; Schantz, Staffan; Sundberg, Johan; Chmelka, Bradley F; Gatenholm, Paul; Nordstierna, Lars

    2016-10-20

    From the assignment of the solid-state (13)C NMR signals in the C4 region, distinct types of crystalline cellulose, cellulose at crystalline surfaces, and disordered cellulose can be identified and quantified. For regenerated cellulose, complete (13)C assignments of the other carbon regions have not previously been attainable, due to signal overlap. In this study, two-dimensional (2D) NMR correlation methods were used to resolve and assign (13)C signals for all carbon atoms in regenerated cellulose. (13)C-enriched bacterial nanocellulose was biosynthesized, dissolved, and coagulated as highly crystalline cellulose II. Specifically, four distinct (13)C signals were observed corresponding to conformationally different anhydroglucose units: two signals assigned to crystalline moieties and two signals assigned to non-crystalline species. The C1, C4 and C6 regions for cellulose II were fully examined by global spectral deconvolution, which yielded qualitative trends of the relative populations of the different cellulose moieties, as a function of wetting and drying treatments. PMID:27474592

  14. High-Resolution Solid-State NMR Spectroscopy: Characterization of Polymorphism in Cimetidine, a Pharmaceutical Compound

    ERIC Educational Resources Information Center

    Pacilio, Julia E.; Tokarski, John T.; Quiñones, Rosalynn; Iuliucci, Robbie J.

    2014-01-01

    High-resolution solid-state NMR (SSNMR) spectroscopy has many advantages as a tool to characterize solid-phase material that finds applications in polymer chemistry, nanotechnology, materials science, biomolecular structure determination, and others, including the pharmaceutical industry. The technology associated with achieving high resolution…

  15. 13C solid-state NMR chemical shift anisotropy analysis of the anomeric carbon in carbohydrates.

    PubMed

    Chen, Ying-Ying; Luo, Shun-Yuan; Hung, Shang-Cheng; Chan, Sunney I; Tzou, Der-Lii M

    2005-03-21

    (13)C NMR solid-state structural analysis of the anomeric center in carbohydrates was performed on six monosaccharides: glucose (Glc), mannose (Man), galactose (Gal), galactosamine hydrochloride (GalN), glucosamine hydrochloride (GlcN), and N-acetyl-glucosamine (GlcNAc). In the 1D (13)C cross-polarization/magic-angle spinning (CP/MAS) spectrum, the anomeric center C-1 of these carbohydrates revealed two well resolved resonances shifted by 3-5ppm, which were readily assigned to the anomeric alpha and beta forms. From this experiment, we also extracted the (13)C chemical shift anisotropy (CSA) tensor elements of the two forms from their spinning sideband intensities, respectively. It was found out that the chemical shift tensor for the alpha anomer was more axially symmetrical than that of the beta form. A strong linear correlation was obtained when the ratio of the axial asymmetry of the (13)C chemical shift tensors of the two anomeric forms was plotted in a semilogarithmic plot against the relative population of the two anomers. Finally, we applied REDOR spectroscopy to discern whether or not there were any differences in the sugar ring conformation between the anomers. Identical two-bond distances of 2.57A (2.48A) were deduced for both the alpha and beta forms in GlcNAc (GlcN), suggesting that the two anomers have essentially identical sugar ring scaffolds in these sugars. In light of these REDOR distance measurements and the strong correlation observed between the ratio of the axial asymmetry parameters of the (13)C chemical shift tensors and the relative population between the two anomeric forms, we concluded that the anomeric effect arises principally from interaction of the electron charge clouds between the C-1-O-5 and the C-1-O-1 bonds in these monosaccharides.

  16. (13)C-(13)c homonuclear recoupling in solid-state nuclear magnetic resonance at a moderately high magic-angle-spinning frequency.

    PubMed

    Mithu, Venus Singh; Bakthavatsalam, Subha; Madhu, Perunthiruthy K

    2013-01-01

    Two-dimensional (13)C-(13)C correlation experiments are widely employed in structure determination of protein assemblies using solid-state nuclear magnetic resonance. Here, we investigate the process of (13)C-(13)C magnetisation transfer at a moderate magic-angle-spinning frequency of 30 kHz using some of the prominent second-order dipolar recoupling schemes. The effect of isotropic chemical-shift difference and spatial distance between two carbons and amplitude of radio frequency on (1)H channel on the magnetisation transfer efficiency of these schemes is discussed in detail.

  17. Study of hydrogen in coals, polymers, oxides, and muscle water by nuclear magnetic resonance; extension of solid-state high-resolution techniques. [Hydrogen molybdenum bronze

    SciTech Connect

    Ryan, L.M.

    1981-10-01

    Nuclear magnetic resonance (NMR) spectroscopy has been an important analytical and physical research tool for several decades. One area of NMR which has undergone considerable development in recent years is high resolution NMR of solids. In particular, high resolution solid state /sup 13/C NMR spectra exhibiting features similar to those observed in liquids are currently achievable using sophisticated pulse techniques. The work described in this thesis develops analogous methods for high resolution /sup 1/H NMR of rigid solids. Applications include characterization of hydrogen aromaticities in fossil fuels, and studies of hydrogen in oxides and bound water in muscle.

  18. Solid state 13C NMR investigation of impact of annealing in lyophilized glasses.

    PubMed

    Luthra, Suman A; Pikal, Michael J; Utz, Marcel

    2008-10-01

    The purpose of this study was to investigate the impact of annealing on molecular mobility in lyophilized glasses, composed of a saccharide excipient and a small concentration of aspartame as a model "drug." Changes in molecular dynamics during annealing were monitored through carbon ((13)C) T(1) and T(1 rho) nuclear magnetic resonance relaxation times of the aspartame and the saccharides. Two different saccharides were studied, sucrose and trehalose. The local mobility of the aspartame guest was found to correlate closely with the overall structural relaxation monitored through calorimetric methods in the aspartame: sucrose formulation. In general terms, annealing leads to longer NMR relaxation times, indicating a slowing of the local dynamics. By contrast, annealing had only a minimal effect on the NMR relaxation times in aspartame: trehalose. Specificity of solid state NMR in detecting molecular mobility in guest and host molecules showed that sucrose provided a homogenous matrix for the guest drug as compared to the trehalose.

  19. 13C solid-state NMR analysis of heterogeneous structure of beeswax in native state

    NASA Astrophysics Data System (ADS)

    Kameda, Tsunenori

    2005-12-01

    I investigated the molecular structure of natural wax from Japanese bees (Apis cerana japonica) in its native state (neither purified nor recrystallized) by 13C and 1H solid-state NMR. Two strong 13C peaks at 32.9 and 34.0 ppm were attributed to signals from internal-chain methylene carbons [int-(CH2)] in two types of crystal form. The peak at 32.9 ppm was assigned to an orthorhombic crystal form, and that at 34.0 ppm was assigned to a triclinic or monoclinic form. In both crystalline regions, bi-exponential decay of 13C spin-lattice relaxation [T1(C)] for the crystalline peaks due to chain diffusion was observed. 1H spin-lattice relaxation [T1(H)] values for protons of the CH3 group and for int-(CH2) in the crystalline and amorphous regions were identical; this was interpreted as being due to averaging of the T1(H) relaxation rates via spin diffusion. In contrast, although the T_{{1}_{\\rho}}(H) decay curves for protons of the CH3 group and for int-(CH2) in the amorphous and orthorhombic forms were almost identical, those of the triclinic or monoclinic forms were different. This unhomogeneous character of T_{{1}_{\\rho}}(H) was interpreted as resulting from differences in the molecular composition of each crystal form. Moreover, two components with long and short 1H spin-spin relaxation [T2(H)] values, arising from the mobile and rigid phases, respectively, were observed at above about -30 °C.

  20. Solid-state 13C NMR study of na-cellulose complexes.

    PubMed

    Porro, Fabrizio; Bédué, Olivier; Chanzy, Henri; Heux, Laurent

    2007-08-01

    The interaction of microcrystalline cellulose from cotton and aqueous sodium hydroxide was investigated by 13C NMR solid-state spectroscopy as a function of temperature and sodium hydroxide concentration. When the concentration of NaOH was increased, the initial cellulose spectrum was replaced successively by that of Na-cellulose I followed by that of Na-cellulose II. In Na-cellulose I, each carbon atom occurred as a singlet, thus implying that one glucosyl moiety was the independent magnetic residue in the structure of this allomorph. In addition, the occurrence of the C6 near 62 ppm is an indication of a gt conformation for the hydroxymethyl group of Na-cellulose I. In Na-cellulose II, the analysis of the resonances of C1 and C6 points toward a structure based on a cellotriosyl moiety as the independent magnetic residue, in agreement with the established X-ray analysis that has shown that for this allomorph, the fiber repeat was also that of a cellotriosyl residue. For Na-cellulose II, the occurrence of the C6 in the 60 ppm region indicates an overall gg conformation for the hydroxymethyl groups. A comparison of the spectra recorded at 268 K and at room temperature confirms the stronger interaction of NaOH with cellulose when the temperature is lowered. In the Q region, corresponding to NaOH concentrations of around 9% and temperatures below 277 K, most of the sample was dissolved and no specific solid-state 13C NMR spectrum could be recorded, except for that of a small fraction of undissolved cellulose I. The same experiment run on a wood pulp sample leads to a new spectrum, with spectral characteristics different from those of Na-cellulose I and Na-cellulose II. This new spectrum is assigned to the Q phase, which appears to result from topological constraints that are present in whole wood pulp fibers but not in microcrystalline cellulose. A spectrum recorded for samples in the Na-cellulose III conditions resembled that of Na-cellulose II but of lower

  1. Sparse (13)C labelling for solid-state NMR studies of P. pastoris expressed eukaryotic seven-transmembrane proteins.

    PubMed

    Liu, Jing; Liu, Chang; Fan, Ying; Munro, Rachel A; Ladizhansky, Vladimir; Brown, Leonid S; Wang, Shenlin

    2016-05-01

    We demonstrate a novel sparse (13)C labelling approach for methylotrophic yeast P. pastoris expression system, towards solid-state NMR studies of eukaryotic membrane proteins. The labelling scheme was achieved by co-utilizing natural abundance methanol and specifically (13)C labelled glycerol as carbon sources in the expression medium. This strategy improves the spectral resolution by 1.5 fold, displays site-specific labelling patterns, and has advantages for collecting long-range distance restraints for structure determination of large eukaryotic membrane proteins by solid-state NMR.

  2. 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.

  3. Structural Characterization of Humic Materials Using ^13C NMR Techniques: A Comparison of Solution- and Solid-State Methods

    NASA Astrophysics Data System (ADS)

    Clewett, Catherine; Alam, Todd; Osantowski, Eric; Pullin, Michael

    2011-10-01

    The analysis of the carbon type distribution and chemical structure of natural organic matter (NOM) by ^13C NMR spectroscopy is an important technique for understanding its origins and reactivity. While prior work has used solution-state NMR techniques, solid-state NMR has the potential to provide this information using less instrument time and sample manipulation, while providing an array of advanced filtering techniques. Analyses of four isolated humic materials with ^13C solid-state magic angle spinning (MAS) NMR techniques are described, including three commercially available samples and one fulvic acid sample isolated from the Rio Grande in New Mexico. This study demonstrates the utility of solid-state ^13C NMR for aquatic NOM structural characterization, comparing these results to the existing solution-state determinations. The solid-state ^13C MAS NMR results are used to determine % carbon distribution, estimates of elemental composition (%C, %H, %(O+N)), aromatic fraction (fa), nonprotonated aromatic fraction (faN), an estimate of aromatic cluster size, and ratio of sp^2 to sp^3 carbons. A Gaussian deconvolution method is introduced that allows for a detailed analysis of carbon type.

  4. Variable-temperature 13C solid-state NMR study of the molecular structure of honeybee wax and silk.

    PubMed

    Kameda, Tsunenori; Tamada, Yasushi

    2009-01-01

    To elucidate the native-state crystal structure of beeswax from the Japanese bee, Apis cerana japonica, we determined the relationship between temperature and the 13C solid-state nuclear magnetic resonance (NMR) chemical shift of methylene carbon of beeswax, with comparison to n-alkanes and polyethylene in the orthorhombic, monoclinic, or triclinic crystal form. Variable-temperature 13C solid-state NMR observations of n-alkanes and polyethylene revealed that the chemical shifts of methylene carbon in the orthorhombic crystal form increased linearly with increasing temperature, that of the triclinic form decreased, and that of the monoclinic form was unaltered. These relations were compared with results of variable-temperature 13C solid-state NMR observation of beeswax. Results clarified that the two crystal forms comprising the beeswax in the native state are orthorhombic and monoclinic. The variable-temperature 13C solid-state NMR observations were also applied to interpret the differential scanning calorimetry (DSC) curve of beeswax. They were used to clarify the structural changes of beeswax for widely various temperatures. For beeswax secreted by the Japanese bee, the transition from the orthorhombic form to the rotator phase occurred at 36 degrees C, that is from the crystalline to the intermediate state at 45 degrees C. Moreover, the variable-temperature 13C solid-state NMR spectrum of honeybee silk in the native state was observed. Results demonstrated that the secondary structures of honeybee silk proteins in the native state comprised coexisting alpha-helix and beta-sheet conformations and that the amount of alpha-helices was greater. The alpha-helix content of honeybee silk was compared with that of hornet silk produced by Vespa larvae.

  5. Solid-state 13C NMR and molecular modeling studies of acetyl aleuritolic acid obtained from Croton cajucara Benth

    NASA Astrophysics Data System (ADS)

    da Silva San Gil, Rosane Aguiar; Albuquerque, Magaly Girão; de Alencastro, Ricardo Bicca; da Cunha Pinto, Angelo; do Espírito Santo Gomes, Fabiano; de Castro Dantas, Tereza Neuma; Maciel, Maria Aparecida Medeiros

    2008-08-01

    Solid-state 13C nuclear magnetic resonance ( 13C NMR) with magic-angle spinning (MAS) and with cross-polarization and magic-angle spinning (CP/MAS) spectra, and differential scanning calorimetry (DSC) techniques were used to obtain structural data from a sample of acetyl aleuritolic acid (AAA) extracted from the stem bark of Croton cajucara Benth. (Euphorbiaceae) and recrystallized from acetone. Since solid-state 13C NMR results suggested the presence of more than one molecule in the unitary cell for the AAA, DSC analysis and molecular modeling calculations were used to access this possibility. The absence of phase transition peaks in the DSC spectra and the dimeric models of AAA simulated using the semi-empirical PM3 method are in agreement with that proposal.

  6. Triple resonance experiments for aligned sample solid-state NMR of 13C and 15N labeled proteins

    PubMed Central

    Sinha, Neeraj; Grant, Christopher V.; Park, Sang Ho; Brown, Jonathan Miles; Opella, Stanley J.

    2013-01-01

    Initial steps in the development of a suite of triple-resonance 1H/13C/15N solid-state NMR experiments applicable to aligned samples of 13C and 15N labeled proteins are described. The experiments take advantage of the opportunities for 13C detection without the need for homonuclear 13C/13C decoupling presented by samples with two different patterns of isotopic labeling. In one type of sample, the proteins are ~20% randomly labeled with 13C in all backbone and side chain carbon sites and ~100% uniformly 15N labeled in all nitrogen sites; in the second type of sample, the peptides and proteins are 13C labeled at only the α-carbon and 15N labeled at the amide nitrogen of a few residues. The requirement for homonuclear 13C/13C decoupling while detecting 13C signals is avoided in the first case because of the low probability of any two 13C nuclei being bonded to each other; in the second case, the labeled 13Cα sites are separated by at least three bonds in the polypeptide chain. The experiments enable the measurement of the 13C chemical shift and 1H–13C and 15N–13C heteronuclear dipolar coupling frequencies associated with the 13Cα and 13C′ backbone sites, which provide orientation constraints complementary to those derived from the 15N labeled amide backbone sites. 13C/13C spin-exchange experiments identify proximate carbon sites. The ability to measure 13C–15N dipolar coupling frequencies and correlate 13C and 15N resonances provides a mechanism for making backbone resonance assignments. Three-dimensional combinations of these experiments ensure that the resolution, assignment, and measurement of orientationally dependent frequencies can be extended to larger proteins. Moreover, measurements of the 13C chemical shift and 1H–13C heteronuclear dipolar coupling frequencies for nearly all side chain sites enable the complete three-dimensional structures of proteins to be determined with this approach. PMID:17293139

  7. (13) C-TmDOTA as versatile thermometer compound for solid-state NMR of hydrated lipid bilayer membranes.

    PubMed

    Umegawa, Yuichi; Tanaka, Yuya; Nobuaki, Matsumori; Murata, Michio

    2016-03-01

    Recent advances in solid-state nuclear magnetic resonance (NMR) techniques, such as magic angle spinning and high-power decoupling, have dramatically increased the sensitivity and resolution of NMR. However, these NMR techniques generate extra heat, causing a temperature difference between the sample in the rotor and the variable temperature gas. This extra heating is a particularly crucial problem for hydrated lipid membrane samples. Thus, to develop an NMR thermometer that is suitable for hydrated lipid samples, thulium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (TmDOTA) was synthesized and labeled with (13) C (i.e., (13) C-TmDOTA) to increase the NMR sensitivity. The complex was mixed with a hydrated lipid membrane, and the system was subjected to solid-state NMR and differential scanning calorimetric analyses. The physical properties of the lipid bilayer and the quality of the NMR spectra of the membrane were negligibly affected by the presence of (13) C-TmDOTA, and the (13) C chemical shift of the complex exhibited a large-temperature dependence. The results demonstrated that (13) C-TmDOTA could be successfully used as a thermometer to accurately monitor temperature changes induced by (1) H decoupling pulses and/or by magic angle spinning and the temperature distribution of the sample inside the rotor. Thus, (13) C-TmDOTA was shown to be a versatile thermometer for hydrated lipid assemblies. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26460094

  8. (13) C-TmDOTA as versatile thermometer compound for solid-state NMR of hydrated lipid bilayer membranes.

    PubMed

    Umegawa, Yuichi; Tanaka, Yuya; Nobuaki, Matsumori; Murata, Michio

    2016-03-01

    Recent advances in solid-state nuclear magnetic resonance (NMR) techniques, such as magic angle spinning and high-power decoupling, have dramatically increased the sensitivity and resolution of NMR. However, these NMR techniques generate extra heat, causing a temperature difference between the sample in the rotor and the variable temperature gas. This extra heating is a particularly crucial problem for hydrated lipid membrane samples. Thus, to develop an NMR thermometer that is suitable for hydrated lipid samples, thulium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (TmDOTA) was synthesized and labeled with (13) C (i.e., (13) C-TmDOTA) to increase the NMR sensitivity. The complex was mixed with a hydrated lipid membrane, and the system was subjected to solid-state NMR and differential scanning calorimetric analyses. The physical properties of the lipid bilayer and the quality of the NMR spectra of the membrane were negligibly affected by the presence of (13) C-TmDOTA, and the (13) C chemical shift of the complex exhibited a large-temperature dependence. The results demonstrated that (13) C-TmDOTA could be successfully used as a thermometer to accurately monitor temperature changes induced by (1) H decoupling pulses and/or by magic angle spinning and the temperature distribution of the sample inside the rotor. Thus, (13) C-TmDOTA was shown to be a versatile thermometer for hydrated lipid assemblies. Copyright © 2015 John Wiley & Sons, Ltd.

  9. High-resolution vector microwave magnetometry based on solid-state spins in diamond

    PubMed Central

    Wang, Pengfei; Yuan, Zhenheng; Huang, Pu; Rong, Xing; Wang, Mengqi; Xu, Xiangkun; Duan, Changkui; Ju, Chenyong; Shi, Fazhan; Du, Jiangfeng

    2015-01-01

    The measurement of the microwave field is crucial for many developments in microwave technology and related applications. However, measuring microwave fields with high sensitivity and spatial resolution under ambient conditions remains elusive. In this work, we propose and experimentally demonstrate a scheme to measure both the strength and orientation of the microwave magnetic field by utilizing the quantum coherent dynamics of nitrogen vacancy centres in diamond. An angular resolution of 5.7 mrad and a sensitivity of 1.0 μT Hz−1/2 are achieved at a microwave frequency of 2.6000 GHz, and the microwave magnetic field vectors generated by a copper wire are precisely reconstructed. The solid-state microwave magnetometry with high resolution and wide frequency range that can work under ambient conditions proposed here enables unique potential applications over other state-of-art microwave magnetometry. PMID:25799155

  10. High-resolution solid-state nuclear magnetic resonance experiments on highly radioactive ceramics

    NASA Astrophysics Data System (ADS)

    Farnan, Ian; Cho, Herman; Weber, William J.; Scheele, Randall D.; Johnson, Nigel R.; Kozelisky, Anne E.

    2004-12-01

    A triple-containment magic-angle spinning rotor insert system has been developed and a sample handling procedure formulated for safely analyzing highly radioactive solids by high-resolution solid-state NMR. The protocol and containment system have been demonstrated for magic-angle spinning (MAS) experiments on ceramic samples containing 5-10 wt % 239Pu and 238Pu at rotation speeds of 3500 Hz. The technique has been used to demonstrate that MAS NMR experiments can be used to measure amorphous atomic number fractions produced by accelerated internal radiation damage. This will allow incorporated α-emitters with short half-lives to be used to model the long-term radiation tolerance of potential ceramic radioactive waste forms. This is an example of MAS NMR spectroscopy on samples containing fissionable isotopes.

  11. High resolution heteronuclear correlation NMR spectroscopy between quadrupolar nuclei and protons in the solid state

    NASA Astrophysics Data System (ADS)

    Goldbourt, A.; Vinogradov, E.; Goobes, G.; Vega, S.

    2004-08-01

    A high resolution two-dimensional solid state NMR experiment is presented that correlates half-integer quadrupolar spins with protons. In this experiment the quadrupolar nuclei evolve during t1 under a split-t1, FAM-enhanced MQMAS pulse scheme. After each t1 period ending at the MQMAS echo position, single quantum magnetization is transferred, via a cross polarization process in the mixing time, from the quadrupolar nuclei to the protons. High-resolution proton signals are then detected in the t2 time domain during wPMLG5* homonuclear decoupling. The experiment has been demonstrated on a powder sample of sodium citrate and 23Na- 1H 2D correlation spectra have been obtained. From the HETCOR spectra and the regular MQMAS spectrum, the three crystallographically inequivalent Na + sites in the asymmetric unit were assigned. This MQMAS- wPMLG HETCOR pulse sequence can be used for spectral editing of half-integer quadrupolar nuclei coupled to protons.

  12. Solid-state fluoroscopic imager for high-resolution angiography: Parallel-cascaded linear systems analysis

    PubMed Central

    Vedantham, Srinivasan; Karellas, Andrew; Suryanarayanan, Sankararaman

    2008-01-01

    Cascaded linear systems based modeling techniques have been used in the past to predict important system parameters that have a direct impact on image quality. Such models are also useful in optimizing system parameters to improve image quality. In this work, detailed analysis of a solid-state fluoroscopic imaging system intended for high-resolution angiography is presented with the use of such a model. The imaging system analyzed through this model uses four 8×8 cm three-side buttable interlined charge-coupled devices (CCDs) specifically designed for high-resolution angiography and tiled in a seamless fashion to achieve a field of view (FOV) of 16×16 cm. Larger FOVs can be achieved by tiling more CCDs in a similar manner. The system employs a CsI:Tl scintillator coupled to the CCDs by straight (nontapering) fiberoptics and can potentially be operated in 78, 156, or 234 μm pixel pitch modes. The system parameters analyzed through this model include presampling modulation transfer function, noise power spectrum, and detective quantum efficiency (DQE). The results of the simulations performed indicate that DQE(0) in excess of 0.6 is achievable, with the imager operating at 156 μm pixel pitch, 30 frames/s, and employing a 450-μm-thick CsI:Tl scintillator, even at a low fluoroscopic exposure rate of 1 μR/frame. Further, at a nominal fluoroscopic exposure rate of 2.5 μR/frame there was no noticeable degradation of the DQE even at the 78 μm pixel pitch mode suggesting that it is feasible to perform high-resolution angiography hitherto unattainable in clinical practice. PMID:15191318

  13. Chemical structural studies of natural lignin by dipolar dephasing solid-state 13C nuclear magnetic resonance

    USGS Publications Warehouse

    Hatcher, P.G.

    1987-01-01

    Two natural lignins, one from a gymnosperm wood the other from angiosperm wood, were examined by conventional solid-state and dipolar dephasing 13C nuclear magnetic resonance (NMR) techniques. The results obtained from both techniques show that the structure of natural lignins is consistent with models of softwood and hardwood lignin. The dipolar dephasing NMR data provide a measure of the degree of substitution on aromatic rings which is consistent with the models. ?? 1987.

  14. Unraveling the complexity of protein backbone dynamics with combined (13)C and (15)N solid-state NMR relaxation measurements.

    PubMed

    Lamley, Jonathan M; Lougher, Matthew J; Sass, Hans Juergen; Rogowski, Marco; Grzesiek, Stephan; Lewandowski, Józef R

    2015-09-14

    Typically, protein dynamics involve a complex hierarchy of motions occurring on different time scales between conformations separated by a range of different energy barriers. NMR relaxation can in principle provide a site-specific picture of both the time scales and amplitudes of these motions, but independent relaxation rates sensitive to fluctuations in different time scale ranges are required to obtain a faithful representation of the underlying dynamic complexity. This is especially pertinent for relaxation measurements in the solid state, which report on dynamics in a broader window of time scales by more than 3 orders of magnitudes compared to solution NMR relaxation. To aid in unraveling the intricacies of biomolecular dynamics we introduce (13)C spin-lattice relaxation in the rotating frame (R1ρ) as a probe of backbone nanosecond-microsecond motions in proteins in the solid state. We present measurements of (13)C'R1ρ rates in fully protonated crystalline protein GB1 at 600 and 850 MHz (1)H Larmor frequencies and compare them to (13)C'R1, (15)N R1 and R1ρ measured under the same conditions. The addition of carbon relaxation data to the model free analysis of nitrogen relaxation data leads to greatly improved characterization of time scales of protein backbone motions, minimizing the occurrence of fitting artifacts that may be present when (15)N data is used alone. We also discuss how internal motions characterized by different time scales contribute to (15)N and (13)C relaxation rates in the solid state and solution state, leading to fundamental differences between them, as well as phenomena such as underestimation of picosecond-range motions in the solid state and nanosecond-range motions in solution.

  15. Solid-state (13)C NMR and synchrotron SAXS/WAXS studies of uniaxially-oriented polyethylene.

    PubMed

    Afeworki, Mobae; Brant, Pat; Lustiger, Arnold; Norman, Alexander

    2015-11-01

    We report solid-state (13)C NMR and synchrotron wide-and small-angle X-ray scattering experiments (WAXS, SAXS) on metallocene linear low density polyethylene films (e.g., Exceed™ 1018 mLLDPE; nominally 1MI, 0.918 density ethylene-hexene metallocene copolymer) as a function of uniaxial draw ratio, λ. Combined, these experiments provide an unambiguous, quantitative molecular view of the orientation of both the crystalline and amorphous phases in the samples as a function of draw. Together with previously reported differential scanning calorimetry (DSC), gas transport measurements, transmission electron microscopy (TEM), optical birefringence, small angle X-ray scattering (SAXS) as well as other characterization techniques, this study of the state of orientation in both phases provides insight concerning the development of unusually high barrier properties of the most oriented samples (λ=10). In this work, static (non-spinning) solid-state NMR measurements indicate that in the drawn Exceed(TM) films both the crystalline and amorphous regions are highly oriented. In particular, chemical shift data show the amorphous phase is comprised increasingly of so-called "taut tie chains" (or tie chains under any state of tautness) in the mLLDPE with increasing draw ratio - the resonance lines associated with the amorphous phase shift to where the crystalline peaks are observed. In the sample with highest total draw (λ=10), virtually all of the chains in the non-crystalline region have responded and aligned in the machine (draw) direction. Both monoclinic and orthorhombic crystalline peaks are observed in high-resolution, solid-state magic-angle spinning (MAS) NMR measurements of the oriented PE films. The orientation is comparable to that obtained for ultra-high molecular weight HDPE fibers described as "ultra-oriented" in the literature. Furthermore, the presence of a monoclinic peak in cold-drawn samples suggests that there is an appreciable internal stress associated

  16. Accurate measurements of {sup 13}C-{sup 13}C distances in uniformly {sup 13}C-labeled proteins using multi-dimensional four-oscillating field solid-state NMR spectroscopy

    SciTech Connect

    Straasø, Lasse Arnt; Nielsen, Jakob Toudahl; Bjerring, Morten; Nielsen, Niels Chr.; Khaneja, Navin

    2014-09-21

    Application of sets of {sup 13}C-{sup 13}C internuclear distance restraints constitutes a typical key element in determining the structure of peptides and proteins by magic-angle-spinning solid-state NMR spectroscopy. Accurate measurements of the structurally highly important {sup 13}C-{sup 13}C distances in uniformly {sup 13}C-labeled peptides and proteins, however, pose a big challenge due to the problem of dipolar truncation. Here, we present novel two-dimensional (2D) solid-state NMR experiments capable of extracting distances between carbonyl ({sup 13}C′) and aliphatic ({sup 13}C{sub aliphatic}) spins with high accuracy. The method is based on an improved version of the four-oscillating field (FOLD) technique [L. A. Straasø, M. Bjerring, N. Khaneja, and N. C. Nielsen, J. Chem. Phys. 130, 225103 (2009)] which circumvents the problem of dipolar truncation, thereby offering a base for accurate extraction of internuclear distances in many-spin systems. The ability to extract reliable accurate distances is demonstrated using one- and two-dimensional variants of the FOLD experiment on uniformly {sup 13}C,{sup 15}N-labeled-L-isoleucine. In a more challenging biological application, FOLD 2D experiments are used to determine a large number of {sup 13}C′-{sup 13}C{sub aliphatic} distances in amyloid fibrils formed by the SNNFGAILSS fibrillating core of the human islet amyloid polypeptide with uniform {sup 13}C,{sup 15}N-labeling on the FGAIL fragment.

  17. Simultaneous cross polarization to 13C and 15N with 1H detection at 60 kHz MAS solid-state NMR

    NASA Astrophysics Data System (ADS)

    Das, Bibhuti B.; Opella, Stanley J.

    2016-01-01

    We describe high resolution MAS solid-state NMR experiments that utilize 1H detection with 60 kHz magic angle spinning; simultaneous cross-polarization from 1H to 15N and 13C nuclei; bidirectional cross-polarization between 13C and 15N nuclei; detection of both amide nitrogen and aliphatic carbon 1H; and measurement of both 13C and 15N chemical shifts through multi-dimensional correlation experiments. Three-dimensional experiments correlate amide 1H and alpha 1H selectively with 13C or 15N nuclei in a polypeptide chain. Two separate three-dimensional spectra correlating 1Hα/13Cα/1HN and 1HN/15N/1Hα are recorded simultaneously in a single experiment, demonstrating that a twofold savings in experimental time is potentially achievable. Spectral editing using bidirectional coherence transfer pathways enables simultaneous magnetization transfers between 15N, 13Cα(i) and 13C‧(i-1), facilitating intra- and inter-residue correlations for sequential resonance assignment. Non-uniform sampling is integrated into the experiments, further reducing the length of experimental time.

  18. High-resolution solid-state 2H NMR spectroscopy of polymorphs of glycine.

    PubMed

    Aliev, Abil E; Mann, Sam E; Rahman, Aisha S; McMillan, Paul F; Corà, Furio; Iuga, Dinu; Hughes, Colan E; Harris, Kenneth D M

    2011-11-10

    High-resolution solid-state (2)H MAS NMR studies of the α and γ polymorphs of fully deuterated glycine (glycine-d(5)) are reported. Analysis of spinning sideband patterns is used to determine the (2)H quadrupole interaction parameters, and is shown to yield good agreement with the corresponding parameters determined from single-crystal (2)H NMR measurements (the maximum deviation in quadrupole coupling constants determined from these two approaches is only 1%). From analysis of simulated (2)H MAS NMR sideband patterns as a function of reorientational jump frequency (κ) for the -N(+)D(3) group in glycine-d(5), the experimentally observed differences in the (2)H MAS NMR spectrum for the -N(+)D(3) deutrons in the α and γ polymorphs is attributed to differences in the rate of reorientation of the -N(+)D(3) group. These simulations show severe broadening of the (2)H MAS NMR signal in the intermediate motion regime, suggesting that deuterons undergoing reorientational motions at rates in the range κ ≈ 10(4)-10(6) s(-1) are likely to be undetectable in (2)H MAS NMR measurements for materials with natural isotopic abundances. The (1)H NMR chemical shifts for the α and γ polymorphs of glycine have been determined from the (2)H MAS NMR results, taking into account the known second-order shift. Further quantum mechanical calculations of (2)H quadrupole interaction parameters and (1)H chemical shifts reveal the structural dependence of these parameters in the two polymorphs and suggest that the existence of two short intermolecular C-H···O contacts for one of the H atoms of the >CH(2) group in the α polymorph have a significant influence on the (2)H quadrupole coupling and (1)H chemical shift for this site. PMID:21939265

  19. Probing polymorphism and reactivity in the organic solid state using 13C NMR spectroscopy: Studies of p-Formyl- trans-cinnamic acid

    NASA Astrophysics Data System (ADS)

    Harris, Kenneth D. M.; Thomas, John M.

    1991-09-01

    p-Formyl- trans-cinnamic acid (p-FCA) is known to exist in two different crystal phases (denoted β and γ). When crystals of the β phase of p-FCA are exposed to UV radiation, a solid state dimerization reaction occurs to produce 4,4'-diformyl-β-truxinic acid. In contrast, crystals of the γ phase of p-FCA are photostable. It is shown in this paper that high resolution solid state 13C NMR spectroscopy is a sensitive technique for distinguishing the β and γ phases of p-FCA, and can be used to investigate, in detail, the chemical transformation that occurs upon UV irradiation of the β phase. Specifically, the 13C NMR spectra presented here were recorded using the TOSS (total suppression of sidebands) pulse sequence; this is based upon the standard 13C CPMAS (cross polarization/magic angle sample spinning/high power 1H decoupling) method, but has the additional feature that all orders of spinning sidebands are eliminated from the spectrum. The photoproduct obtained from UV irradiation of β-p-FCA contains a significant noncrystalline component (assessed via powder X-ray diffraction), and our NMR studies suggest that this noncrystalline component of the photoproduct contains some amount of the γ phase of the monomer p-FCA. A mechanism is proposed to explain the fact that UV irradiation of β-p-FCA can generate, in addition to the expected photodimer, an impurity amount of the γ phase of p-FCA.

  20. Solid state high resolution multi-spectral imager CCD test phase

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The program consisted of measuring the performance characteristics of charge coupled linear imaging devices, and a study defining a multispectral imaging system employing advanced solid state photodetection techniques.

  1. Solid-State Selective 13C Excitation and Spin Diffusion NMR to Resolve Spatial Dimensions in Plant Cell Walls

    SciTech Connect

    Foston, M.; Katahira, R.; Gjersing, E.; Davis, M. F.; Ragauskas, A. J.

    2012-02-15

    The average spatial dimensions between major biopolymers within the plant cell wall can be resolved using a solid-state NMR technique referred to as a {sup 13}C cross-polarization (CP) SELDOM (selectively by destruction of magnetization) with a mixing time delay for spin diffusion. Selective excitation of specific aromatic lignin carbons indicates that lignin is in close proximity to hemicellulose followed by amorphous and finally crystalline cellulose. {sup 13}C spin diffusion time constants (T{sub SD}) were extracted using a two-site spin diffusion theory developed for {sup 13}C nuclei under magic angle spinning (MAS) conditions. These time constants were then used to calculate an average lower-limit spin diffusion length between chemical groups within the plant cell wall. The results on untreated {sup 13}C enriched corn stover stem reveal that the lignin carbons are, on average, located at distances {approx}0.7-2.0 nm from the carbons in hemicellulose and cellulose, whereas the pretreated material had larger separations.

  2. Differentiation of histidine tautomeric states using 15N selectively filtered 13C solid-state NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Miao, Yimin; Cross, Timothy A.; Fu, Riqiang

    2014-08-01

    The histidine imidazole ring in proteins usually contains a mixture of three possible tautomeric states (two neutral - τ and π states and a charged state) at physiological pHs. Differentiating the tautomeric states is critical for understanding how the histidine residue participates in many structurally and functionally important proteins. In this work, one dimensional 15N selectively filtered 13C solid-state NMR spectroscopy is proposed to differentiate histidine tautomeric states and to identify all 13C resonances of the individual imidazole rings in a mixture of tautomeric states. When 15N selective 180° pulses are applied to the protonated or non-protonated nitrogen region, the 13C sites that are bonded to the non-protonated or protonated nitrogen sites can be identified, respectively. A sample of 13C, 15N labeled histidine powder lyophilized from a solution at pH 6.3 has been used to illustrate the usefulness of this scheme by uniquely assigning resonances of the neutral τ and charged states from the mixture.

  3. High-resolution proton NMR studies of intracellular metabolites in yeast using 13C decoupling

    NASA Astrophysics Data System (ADS)

    Sillerud, Laurel O.; Alger, Jeffry R.; Shulman, Robert G.

    The resolution and specificity of 1H NMR in studies of yeast cellular metabolism were increased by feeding a 13C-labeled substrate and observing 1H difference spectra in the presence and absence of 13C decoupling fields. [2- 13C]Acetate was utilized as a respiratory substrate in an aerobic suspension of Saccharomyces cerevisiae. The broad cellular background proton resonances are removed by the technique, leaving only signals from the protons of the substrate, or its metabolites, that are coupled to 13C. Spectra of the yeast suspension after acetate feeding show the disappearance of label from the acetate pool and the subsequent appearance of 13C in glutamate C 3 and C 4 and in aspartate C 3. These results are in accord with the known fluxes of metabolites. Selective single-frequency 13C decoupling was used to provide assignments for the difference signals. The limitations on single-frequency decoupling coming from finite decoupling fields are investigated. The technique shows a potential for application in a wide variety of systems where the resolution of the 13C spectrum may be combined with the sensitivity for proton detection to observe metabolites that have been previously unobservable.

  4. Solid-state (13)C NMR reveals effects of temperature and hydration on elastin.

    PubMed Central

    Perry, Ashlee; Stypa, Michael P; Tenn, Brandon K; Kumashiro, Kristin K

    2002-01-01

    Elastin is the principal protein component of the elastic fiber in vertebrate tissue. The waters of hydration in the elastic fiber are believed to play a critical role in the structure and function of this largely hydrophobic, amorphous protein. (13)C CPMAS NMR spectra are acquired for elastin samples with different hydration levels. The spectral intensities in the aliphatic region undergo significant changes as 70% of the water in hydrated elastin is removed. In addition, dramatic differences in the CPMAS spectra of hydrated, lyophilized, and partially dehydrated elastin samples over a relatively small temperature range (-20 degrees C to 37 degrees C) are observed. Results from other experiments, including (13)C T(1) and (1)H T(1 rho) measurements, direct polarization with magic-angle spinning, and static CP of the hydrated and lyophilized elastin preparations, also support the model that there is significant mobility in fully hydrated elastin. Our results support models in which water plays an integral role in the structure and proper function of elastin in vertebrate tissue. PMID:11806948

  5. Characterisation of black carbon-rich samples by (13)C solid-state nuclear magnetic resonance.

    PubMed

    Novotny, Etelvino H; Hayes, Michael H B; Deazevedo, Eduardo R; Bonagamba, Tito J

    2006-09-01

    There are difficulties in quantifying and characterising the organic matter (OM) in soils that contain significant amounts of partially oxidised char or charcoal materials. The anthropogenic black carbon (BC), such as that found in the Terra Preta de Indio soils of the Amazon region, is a good example of the OM that is difficult to analyse in such soils. (13)C direct polarisation/magic angle spinning (DP/MAS) at high MAS frequency, (1)H-(13)C cross polarisation (CP)/MAS with total suppression of spinning sidebands (TOSS), and chemical shift anisotropy (CSA) filter nuclear magnetic resonance techniques have been applied successfully for quantifying the different components of OM. However, because pyrogenic materials present strong local magnetic susceptibility heterogeneities, the use of CSA-filter and TOSS make the pulse sequences very sensitive to imperfections in the pi pulses. In this study, the DP/MAS pulse sequence was replaced by a CP with a radio frequency ramp--variable amplitude CP (VACP)--VACP/MAS pulse sequence, and composite pi pulses were used in the CSA-filter and TOSS pulse sequences. In that way, the component functionalities in a humic acid from a BC soil were successfully determined. The spectrometer time needed was greatly decreased by employing this VACP/MAS technique. This development provides an accurate method for characterising BC-rich samples from different origins. PMID:16688435

  6. Characterisation of black carbon-rich samples by 13C solid-state nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Novotny, Etelvino H.; Hayes, Michael H. B.; Deazevedo, Eduardo R.; Bonagamba, Tito J.

    2006-09-01

    There are difficulties in quantifying and characterising the organic matter (OM) in soils that contain significant amounts of partially oxidised char or charcoal materials. The anthropogenic black carbon (BC), such as that found in the Terra Preta de Índio soils of the Amazon region, is a good example of the OM that is difficult to analyse in such soils. 13C direct polarisation/magic angle spinning (DP/MAS) at high MAS frequency, 1H-13C cross polarisation (CP)/MAS with total suppression of spinning sidebands (TOSS), and chemical shift anisotropy (CSA) filter nuclear magnetic resonance techniques have been applied successfully for quantifying the different components of OM. However, because pyrogenic materials present strong local magnetic susceptibility heterogeneities, the use of CSA-filter and TOSS make the pulse sequences very sensitive to imperfections in the π pulses. In this study, the DP/MAS pulse sequence was replaced by a CP with a radio frequency ramp—variable amplitude CP (VACP)—VACP/MAS pulse sequence, and composite π pulses were used in the CSA-filter and TOSS pulse sequences. In that way, the component functionalities in a humic acid from a BC soil were successfully determined. The spectrometer time needed was greatly decreased by employing this VACP/MAS technique. This development provides an accurate method for characterising BC-rich samples from different origins.

  7. Solid-state 13C nuclear magnetic resonance studies of coalified gymnosperm xylem tissue from Australian brown coals

    USGS Publications Warehouse

    Hatcher, P.G.; Lerch, H. E.; Bates, A.L.; Verheyen, T.V.

    1989-01-01

    We report here on the use of solid-state 13C nuclear magnetic resonance (NMR) spectroscopy to contrast the average chemical composition of modern degraded gymnosperm woods with fossil gymnosperm woods from Australian brown coals (Miocene). We first established the quantitative nature of the NMR techniques for these samples so that the conventional solid-state 13C NMR spectra and the dipolar dephasing NMR spectra could be used with a high degree of reliability to depict average chemical compositions. The NMR results provide some valuable insights about the early coalification of xylem tissue from gymnosperms. Though the cellulosic components of wood are degraded to varying degrees during peatification and ensuing coalification, it is unlikely that they play a major role in the formation of aromatic structures in coalified woods. The NMR data show that gynmosperm lignin, the primary aromatic contribution to the coal, is altered in part by demethylation of guaiacyl-units to catechol-like structures. The dipolar dephasing NMR data indicate that the lignin also becomes more cross-linked or condensed. ?? 1989.

  8. 13C Solid State Nuclear Magnetic Resonance and µ-Raman Spectroscopic Characterization of Sicilian Amber.

    PubMed

    Barone, Germana; Capitani, Donatella; Mazzoleni, Paolo; Proietti, Noemi; Raneri, Simona; Longobardo, Ugo; Di Tullio, Valeria

    2016-08-01

    (13)C cross-polarization magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) and µ-Raman spectroscopy were applied to characterize Sicilian amber samples. The main goal of this work was to supply a complete study of simetite, highlighting discriminating criteria useful to distinguish Sicilian amber from fossil resins from other regions and laying the foundations for building a spectroscopic database of Sicilian amber. With this aim, a private collection of unrefined simetite samples and fossil resins from the Baltic region and Dominican Republic was analyzed. Overall, the obtained spectra permitted simetite to be distinguished from the other resins. In addition, principal component analysis (PCA) was applied to the spectroscopic data, allowing the clustering of simetite samples with respect to the Baltic and Dominican samples and to group the simetite samples in two sets, depending on their maturity. Finally, the analysis of loadings allowed for a better understanding of the spectral features that mainly influenced the discriminating characteristics of the investigated ambers.

  9. Multidimensional solid-state NMR studies of the structure and dynamics of pectic polysaccharides in uniformly 13C-labeled Arabidopsis primary cell walls

    SciTech Connect

    Dick-Perez, Marilu; Wang, Tuo; Salazar, Andre; Zabotina, Olga A.; Hong, Mei

    2012-07-08

    Plant cell wall (CW) polysaccharides are responsible for the mechanical strength and growth of plant cells; however, the high-resolution structure and dynamics of the CW polysaccharides are still poorly understood because of the insoluble nature of these molecules. Here, we use 2D and 3D magic-angle-spinning (MAS) solid-state NMR (SSNMR) to investigate the structural role of pectins in the plant CW. Intact and partially depectinated primary CWs of Arabidopsis thaliana were uniformly labeled with 13C and their NMR spectra were compared. Recent 13C resonance assignment of the major polysaccharides in Arabidopsis thaliana CWs allowed us to determine the effects of depectination on the intermolecular packing and dynamics of the remaining wall polysaccharides. 2D and 3D correlation spectra show the suppression of pectin signals, confirming partial pectin removal by chelating agents and sodium carbonate. Importantly, higher cross peaks are observed in 2D and 3D 13C spectra of the depectinated CW, suggesting higher rigidity and denser packing of the remaining wall polysaccharides compared with the intact CW. 13C spin–lattice relaxation times and 1H rotating-frame spin–lattice relaxation times indicate that the polysaccharides are more rigid on both the nanosecond and microsecond timescales in the depectinated CW. Taken together, these results indicate that pectic polysaccharides are highly dynamic and endow the polysaccharide network of the primary CW with mobility and flexibility, which may be important for pectin functions. This study demonstrates the capability of multidimensional SSNMR to determine the intermolecular interactions and dynamic structures of complex plant materials under near-native conditions. Copyright © 2012 John Wiley & Sons, Ltd.

  10. 13C Solid State Nuclear Magnetic Resonance and µ-Raman Spectroscopic Characterization of Sicilian Amber.

    PubMed

    Barone, Germana; Capitani, Donatella; Mazzoleni, Paolo; Proietti, Noemi; Raneri, Simona; Longobardo, Ugo; Di Tullio, Valeria

    2016-08-01

    (13)C cross-polarization magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) and µ-Raman spectroscopy were applied to characterize Sicilian amber samples. The main goal of this work was to supply a complete study of simetite, highlighting discriminating criteria useful to distinguish Sicilian amber from fossil resins from other regions and laying the foundations for building a spectroscopic database of Sicilian amber. With this aim, a private collection of unrefined simetite samples and fossil resins from the Baltic region and Dominican Republic was analyzed. Overall, the obtained spectra permitted simetite to be distinguished from the other resins. In addition, principal component analysis (PCA) was applied to the spectroscopic data, allowing the clustering of simetite samples with respect to the Baltic and Dominican samples and to group the simetite samples in two sets, depending on their maturity. Finally, the analysis of loadings allowed for a better understanding of the spectral features that mainly influenced the discriminating characteristics of the investigated ambers. PMID:27340217

  11. Uniform isotope labeling of a eukaryotic seven-transmembrane helical protein in yeast enables high-resolution solid-state NMR studies in the lipid environment.

    PubMed

    Fan, Ying; Shi, Lichi; Ladizhansky, Vladimir; Brown, Leonid S

    2011-02-01

    Overexpression of isotope-labeled multi-spanning eukaryotic membrane proteins for structural NMR studies is often challenging. On the one hand, difficulties with achieving proper folding, membrane insertion, and native-like post-translational modifications frequently disqualify bacterial expression systems. On the other hand, eukaryotic cell cultures can be prohibitively expensive. One of the viable alternatives, successfully used for producing proteins for solution NMR studies, is yeast expression systems, particularly Pichia pastoris. We report on successful implementation and optimization of isotope labeling protocols, previously used for soluble secreted proteins, to produce homogeneous samples of a eukaryotic seven-transmembrane helical protein, rhodopsin from Leptosphaeria maculans. Even in shake-flask cultures, yields exceeded 5 mg of purified uniformly (13)C,(15)N-labeled protein per liter of culture. The protein was stable (at least several weeks at 5°C) and functionally active upon reconstitution into lipid membranes at high protein-to-lipid ratio required for solid-state NMR. The samples gave high-resolution (13)C and (15)N solid-state magic angle spinning NMR spectra, amenable to a detailed structural analysis. We believe that similar protocols can be adopted for challenging mammalian targets, which often resist characterization by other structural methods.

  12. Solid-state 13C NMR studies of a large fossil gymnosperm from the Yallourn Open Cut, Latrobe Valley, Australia

    USGS Publications Warehouse

    Bates, A.L.; Hatcher, P.G.

    1989-01-01

    A series of samples taken from the cross section of a 3-m-diameter fossilized gymnospermous log (Araucariaceae) in the Yallourn Seam of the Australian brown coals was examined by solid state 13C nuclear magnetic resonance to delineate chemical changes related to the combined processes of peatification and coalification. The results show that cellulosic materials were degraded and lost on the periphery of the log, however, the degree of such degradation in the central core is substantially less. The lignin is uniformly altered by coalification reactions to a macromolecular substance displaying decreased aryl ether linkages but significantly greater amounts of carbon linkages compared to modern lignin. Changes in the methoxyl carbon contents of lignin in cross section reveal demethylation reactions, but these do not appear to be related to degree of carbon linking. Both the degredation of cellulosic materials and demethylation of lignin appear to be early diagenetic processes occurring during peatification independently of the coalification reactions. ?? 1989.

  13. Solid state 13C NMR and FT-IR spectroscopy of the cocoon silk of two common spiders

    NASA Astrophysics Data System (ADS)

    Bramanti, Emilia; Catalano, Donata; Forte, Claudia; Giovanneschi, Mario; Masetti, Massimo; Veracini, Carlo Alberto

    2005-11-01

    The structure of the silk from cocoons of two common spiders, Araneus diadematus (family Araneidae) and Achaearanea tepidariorum (family Theridiidae) was investigated by means of 13C solid state NMR and FT-IR spectroscopies. The combined use of these two techniques allowed us to highlight differences in the two samples. The cocoon silk of Achaearanea tepidariorum is essentially constituted by helical and β-sheet structures, whereas that of Araneus diadematus shows a more complex structure, containing also β-strands and β-turns. Moreover, the former silk is essentially crystalline while the latter contains more mobile domains. The structural differences of the two cocoon silks are ascribed to the different habitat of the two species.

  14. Hydrothermal carbon from biomass: structural differences between hydrothermal and pyrolyzed carbons via 13C solid state NMR.

    PubMed

    Falco, Camillo; Perez Caballero, Fernando; Babonneau, Florence; Gervais, Christel; Laurent, Guillaume; Titirici, Maria-Magdalena; Baccile, Niki

    2011-12-01

    The objective of this paper is to better describe the structure of the hydrothermal carbon (HTC) process and put it in relationship with the more classical pyrolytic carbons. Indeed, despite the low energetic impact and the number of applications described so far for HTC, very little is known about the structure, reaction mechanism, and the way these materials relate to coals. Are HTC and calcination processes equivalent? Are the structures of the processed materials related to each other in any way? Which is the extent of polyaromatic hydrocarbons (PAH) inside HTC? In this work, the effect of hydrothermal treatment and pyrolysis are compared on glucose, a good model carbohydrate; a detailed single-quantum double-quantum (SQ-DQ) solid state (13)C NMR study of the HTC and calcined HTC is used to interpret the spectral region corresponding to the signal of furanic and arene groups. These data are compared to the spectroscopic signatures of calcined glucose, starch, and xylose. A semiquantitative analysis of the (13)C NMR spectra provides an estimation of the furanic-to-arene ratio which varies from 1:1 to 4:1 according to the processing conditions and carbohydrate employed. In addition, we formulate some hypothesis, validated by DFT (density functional theory) modeling associated with (13)C NMR chemical shifts calculations, about the possible furan-rich structural intermediates that occur in the coalification process leading to condensed polyaromatic structures. In combination with a broad parallel study on the HTC processing conditions effect on glucose, cellulose, and raw biomass (Falco, C.; Baccile, N.; Titirici, M.-M. Green Chem., 2011, DOI: 10.1039/C1GC15742F), we propose a broad reaction scheme and in which we show that, through HTC, it is possible to tune the furan-to-arene ratio composing the aromatic core of the produced HTC carbons, which is not possible if calcination is used alone, in the temperature range below 350 °C. PMID:22050004

  15. High-resolution (13)C nuclear magnetic resonance spectroscopy pattern recognition of fish oil capsules.

    PubMed

    Aursand, Marit; Standal, Inger B; Axelson, David E

    2007-01-10

    13C NMR (nuclear magnetic resonance) spectroscopy, in conjunction with multivariate analysis of commercial fish oil-related health food products, have been used to provide discrimination concerning the nature, composition, refinement, and/or adulteration or authentication of the products. Supervised (probabilistic neural networks, PNN) and unsupervised (principal component analysis, PCA; Kohonen neural networks; generative topographic mapping, GTM) pattern recognition techniques were used to visualize and classify samples. Simple PCA score plots demonstrated excellent, but not totally unambiguous, class distinctions, whereas Kohonen and GTM visualization provided better results. Quantitative class predictions with accuracies >95% were achieved with PNN analysis. Trout, salmon, and cod oils were completely and correctly classified. Samples reported to be salmon oils and cod liver oils did not cluster with true salmon and cod liver oil samples, indicating mislabeling or adulteration.

  16. Structural characterization of ion-vapor deposited hydrogenated amorphous carbon coatings by solid state {sup 13}C nuclear magnetic resonance

    SciTech Connect

    Xu, Jiao; Kato, Takahisa; Watanabe, Sadayuki; Hayashi, Hideo; Kawaguchi, Masahiro

    2014-01-07

    In the present study, unique structural heterogeneity was observed in ion-vapor deposited a-C:H coatings by performing {sup 13}C MAS and {sup 1}H-{sup 13}C CPMAS experiments on solid state nuclear magnetic resonance devices. Two distinct types of sp{sup 2} C clusters were discovered: one of them denoted as sp{sup 2} C′ in content of 3–12 at. % was non-protonated specifically localized in hydrogen-absent regions, while the other dominant one denoted as sp{sup 2} C″ was hydrogenated or at least proximate to proton spins. On basis of the notably analogous variation of sp{sup 2} C′ content and Raman parameters as function of substrate bias voltage in the whole range of 0.5 kV–3.5 kV, a model of nano-clustering configuration was proposed that the sp{sup 2} C′ clusters were embedded between sp{sup 2} C″ clusters and amorphous sp{sup 3} C matrix as trapped interfaces or boundaries where the sp{sup 2} carbon bonds were highly distorted. Continuous increase of bias voltage would promote the nano-clustering and re-ordering of dominant sp{sup 2} C″ clusters, thus results in a marked decrease of interspace and a change of the content of sp{sup 2} C′ clusters. Further investigation on the {sup 13}C magnetization recovery showed typical stretched-exponential approximation due to the prominent presence of paramagnetic centers, and the stretched power α varied within 0.6–0.9 from distinct types of sp{sup 2} C clusters. Differently, the magnetization recovery of {sup 1}H showed better bi-exponential approximation with long and short T{sub 1}(H) fluctuated within 40–60 ms and 0.1–0.3 ms approximately in content of 80% ± 5% and 20% ± 5%, respectively, varying with various bias voltages. Meanwhile, the interrupted {sup 13}C saturation recovery with an interval of short T{sub 1}(H) showed that most of quick-relaxing protons were localized in sp{sup 2} C″ clusters. Such a short T{sub 1}(H) was only possibly resulted from a relaxation mechanism

  17. Identification of Li-Ion Battery SEI Compounds through (7)Li and (13)C Solid-State MAS NMR Spectroscopy and MALDI-TOF Mass Spectrometry.

    PubMed

    Huff, Laura A; Tavassol, Hadi; Esbenshade, Jennifer L; Xing, Wenting; Chiang, Yet-Ming; Gewirth, Andrew A

    2016-01-13

    Solid-state (7)Li and (13)C MAS NMR spectra of cycled graphitic Li-ion anodes demonstrate SEI compound formation upon lithiation that is followed by changes in the SEI upon delithiation. Solid-state (13)C DPMAS NMR shows changes in peaks associated with organic solvent compounds (ethylene carbonate and dimethyl carbonate, EC/DMC) upon electrochemical cycling due to the formation of and subsequent changes in the SEI compounds. Solid-state (13)C NMR spin-lattice (T1) relaxation time measurements of lithiated Li-ion anodes and reference poly(ethylene oxide) (PEO) powders, along with MALDI-TOF mass spectrometry results, indicate that large-molecular-weight polymers are formed in the SEI layers of the discharged anodes. MALDI-TOF MS and NMR spectroscopy results additionally indicate that delithiated anodes exhibit a larger number of SEI products than is found in lithiated anodes. PMID:26653886

  18. Humic acids as proxies for assessing different Mediterranean forest soils signatures using solid-state CPMAS 13C NMR spectroscopy.

    PubMed

    Duarte, Regina M B O; Fernández-Getino, Ana P; Duarte, Armando C

    2013-06-01

    Humic acids (HAs) of four representative forest soils profiles from Central Spain (two with different vegetation - pine and oak - but same parent material - granitie, and two with same vegetation - holm oak - but different parent material - granite and limestone) were investigated by solid-state cross polarization with magic angle spinning (13)C nuclear magnetic resonance (NMR) spectroscopy. The objectives included the investigation of the impact of different forest properties on HA composition, assessing how the structural characteristics of the HA vary with soil depth, and evaluating the role of HA as surrogates for mapping the different forest soils signatures using structural data derived from (13)C NMR spectroscopy. On average, alkyl C is the dominant C constituent (38-48% of the total NMR peak area) in all HA samples, followed by aromatic (12-22%) and O-alkyl C (12-19%), and finally carboxyl C (7.0-10%). The NMR data also indicated that HA composition is likely to be differently affected by the soil physico-chemical properties and type of forest vegetation. The structural characteristics of the HA from soil under oak did not differ broadly downward in the profile, whereas soil HA under pine forest exhibits a somewhat higher recalcitrant nature as a consequence of a higher degree of decomposition. The soil HA from holm oak forests differed from the other two forest soils, exhibiting a progressive decomposition of the alkyl C structures with increasing depth, while the carbohydrate-like indicator (O-alkyl C) is apparently being protected from mineralization in the horizons below the ground level. Overall, these differences in soil HA NMR signatures are an important diagnostic tool for understanding the role of different soil environmental factors on the structural composition of HA from Mediterranean forest soils. PMID:23332874

  19. Humic acids as proxies for assessing different Mediterranean forest soils signatures using solid-state CPMAS 13C NMR spectroscopy.

    PubMed

    Duarte, Regina M B O; Fernández-Getino, Ana P; Duarte, Armando C

    2013-06-01

    Humic acids (HAs) of four representative forest soils profiles from Central Spain (two with different vegetation - pine and oak - but same parent material - granitie, and two with same vegetation - holm oak - but different parent material - granite and limestone) were investigated by solid-state cross polarization with magic angle spinning (13)C nuclear magnetic resonance (NMR) spectroscopy. The objectives included the investigation of the impact of different forest properties on HA composition, assessing how the structural characteristics of the HA vary with soil depth, and evaluating the role of HA as surrogates for mapping the different forest soils signatures using structural data derived from (13)C NMR spectroscopy. On average, alkyl C is the dominant C constituent (38-48% of the total NMR peak area) in all HA samples, followed by aromatic (12-22%) and O-alkyl C (12-19%), and finally carboxyl C (7.0-10%). The NMR data also indicated that HA composition is likely to be differently affected by the soil physico-chemical properties and type of forest vegetation. The structural characteristics of the HA from soil under oak did not differ broadly downward in the profile, whereas soil HA under pine forest exhibits a somewhat higher recalcitrant nature as a consequence of a higher degree of decomposition. The soil HA from holm oak forests differed from the other two forest soils, exhibiting a progressive decomposition of the alkyl C structures with increasing depth, while the carbohydrate-like indicator (O-alkyl C) is apparently being protected from mineralization in the horizons below the ground level. Overall, these differences in soil HA NMR signatures are an important diagnostic tool for understanding the role of different soil environmental factors on the structural composition of HA from Mediterranean forest soils.

  20. Molecular composition of recycled organic wastes, as determined by solid-state {sup 13}C NMR and elemental analyses

    SciTech Connect

    Eldridge, S.M.; Chen, C.R.; Xu, Z.H.; Nelson, P.N.; Boyd, S.E.; Meszaros, I.; Chan, K.Y.

    2013-11-15

    Highlights: • Model estimated the molecular C components well for most RO wastes. • Molecular nature of organic matter in RO wastes varied widely. • Molecular composition by NMR modelling preferable to extraction techniques. • Some model shortcomings in estimating molecular composition of biochars. • Waste molecular composition important for carbon/nutrient outcomes in soil. - Abstract: Using solid state {sup 13}C NMR data and elemental composition in a molecular mixing model, we estimated the molecular components of the organic matter in 16 recycled organic (RO) wastes representative of the major materials generated in the Sydney basin area. Close correspondence was found between the measured NMR signal intensities and those predicted by the model for all RO wastes except for poultry manure char. Molecular nature of the organic matter differed widely between the RO wastes. As a proportion of organic C, carbohydrate C ranged from 0.07 to 0.63, protein C from <0.01 to 0.66, lignin C from <0.01 to 0.31, aliphatic C from 0.09 to 0.73, carbonyl C from 0.02 to 0.23, and char C from 0 to 0.45. This method is considered preferable to techniques involving imprecise extraction methods for RO wastes. Molecular composition data has great potential as a predictor of RO waste soil carbon and nutrient outcomes.

  1. Molecular composition of recycled organic wastes, as determined by solid-state 13C NMR and elemental analyses.

    PubMed

    Eldridge, S M; Chen, C R; Xu, Z H; Nelson, P N; Boyd, S E; Meszaros, I; Chan, K Y

    2013-11-01

    Using solid state (13)C NMR data and elemental composition in a molecular mixing model, we estimated the molecular components of the organic matter in 16 recycled organic (RO) wastes representative of the major materials generated in the Sydney basin area. Close correspondence was found between the measured NMR signal intensities and those predicted by the model for all RO wastes except for poultry manure char. Molecular nature of the organic matter differed widely between the RO wastes. As a proportion of organic C, carbohydrate C ranged from 0.07 to 0.63, protein C from <0.01 to 0.66, lignin C from <0.01 to 0.31, aliphatic C from 0.09 to 0.73, carbonyl C from 0.02 to 0.23, and char C from 0 to 0.45. This method is considered preferable to techniques involving imprecise extraction methods for RO wastes. Molecular composition data has great potential as a predictor of RO waste soil carbon and nutrient outcomes.

  2. Solid-state 13C NMR studies of dissolved organic matter in pore waters from different depositional environments

    USGS Publications Warehouse

    Orem, W.H.; Hatcher, P.G.

    1987-01-01

    Dissolved organic matter (DOM) in pore waters from sediments of a number of different depositional environments was isolated by ultrafiltration using membranes with a nominal molecular weight cutoff of 500. This > 500 molecular weight DOM represents 70-98% of the total DOM in these pore waters. We determined the gross chemical structure of this material using both solid-state 13C nuclear magnetic resonance spectroscopy and elemental analysis. Our results show that the DOM in these pore waters appears to exist as two major types: one type dominated by carbohydrates and paraffinic structures and the second dominated by paraffinic and aromatic structures. We suggest that the dominance of one or the other structural type of DOM in the pore water depends on the relative oxidizing/reducing nature of the sediments as well as the source of the detrital organic matter. Under dominantly anaerobic conditions carbohydrates in the sediments are degraded by bacteria and accumulate in the pore water as DOM. However, little or no degradation of lignin occurs under these conditions. In contrast, sediments thought to be predominantly aerobic in character have DOM with diminished carbohydrate and enhanced aromatic character. The aromatic structures in the DOM from these sediments are thought to arise from the degradation of lignin. The large amounts of paraffinic structures in both types of DOM may be due to the degradation of unidentified paraffinic materials in algal or bacterial remains. ?? 1987.

  3. Quantitative solid-state 13C nuclear magnetic resonance spectrometric analyses of wood xylen: effect of increasing carbohydrate content

    USGS Publications Warehouse

    Bates, A.L.; Hatcher, P.G.

    1992-01-01

    Isolated lignin with a low carbohydrate content was spiked with increasing amounts of alpha-cellulose, and then analysed by solid-state 13C nuclear magnetic resonance (NMR) using cross-polarization with magic angle spinning (CPMAS) and dipolar dephasing methods in order to assess the quantitative reliability of CPMAS measurement of carbohydrate content and to determine how increasingly intense resonances for carbohydrate carbons affect calculations of the degree of lignin's aromatic ring substitution and methoxyl carbon content. Comparisons were made of the carbohydrate content calculated by NMR with carbohydrate concentrations obtained by phenol-sulfuric acid assay and by the calculation from the known amounts of cellulose added. The NMR methods used in this study yield overestimates for carbohydrate carbons due to resonance area overlap from the aliphatic side chain carbons of lignin. When corrections are made for these overlapping resonance areas, the NMR results agree very well with results obtained by other methods. Neither the calculated methoxyl carbon content nor the degree of aromatic ring substitution in lignin, both calculated from dipolar dephasing spectra, change with cellulose content. Likewise, lignin methoxyl content does not correlate with cellulose abundance when measured by integration of CPMAS spectra. ?? 1992.

  4. Hydration properties of regioselectively etherified celluloses monitored by 2H and 13C solid-state MAS NMR spectroscopy.

    PubMed

    Larsen, Flemming H; Schöbitz, Michael; Schaller, Jens

    2012-06-20

    The hydration properties of 2,3-O-hydroxypropylcellulose (HPC) and 2,3-O-hydroxyethylcellulose (HEC) were analyzed by multi-nuclear solid-state MAS NMR spectroscopy. By 13C single-pulse (SP) MAS and cross-polarization (CP) MAS NMR, differences between the immobile regions and all parts of the polysaccharides were detected as a function of hydration. Complementary information about the water environments was observed by 2H MAS NMR. By this approach it was demonstrated that side chains in 2,3-O-HPC and 2,3-O-HEC were easier to hydrate than the cellulose backbone. Furthermore the motion of water was more restricted (slower) in 2,3-O-HPC than in 2,3-O-HEC. For both polysaccharides the hydration could be explained by a two-step process: in step one increased ordering of the immobile regions occurs after which the entire polymer is hydrated in step two.

  5. Comparison of celery (Apium graveolens L.) collenchyma and parenchyma cell wall polysaccharides enabled by solid-state (13)C NMR.

    PubMed

    Zujovic, Zoran; Chen, Da; Melton, Laurence D

    2016-02-01

    Collenchyma cells with their thickened walls are one of specific mechanical support tissues for plants, while parenchyma cells are thin walled and serve multiple functions. The parenchyma tissue is what you enjoy eating, while collenchyma, because of its fibrous nature, is not so attractive. Celery is a useful model for comparing the cell walls (CWs) of the two cell types such as collenchyma and parenchyma. However, to date, the structural characteristics of collenchyma and parenchyma cell walls from the same plant have not been compared. Monosaccharide composition suggested the collenchyma cell walls contained less pectin but more hemicellulose in comparison to parenchyma. High-resolution solid-state NMR spectra of highly mobile pectins revealed that the arabinan signals were more evident in the collenchyma spectrum, while galactan showed a much stronger resonance in the parenchyma spectrum. In addition, methyl esterified and non-esterified galacturonic acid signals were observed in parenchyma CWs, but only the latter one appeared in the collenchyma. The ratio of cellulose surface/interior obtained from CP/MAS spectra for collenchyma suggested the cellulose microfibrils were ~2.4 nm, while in the parenchyma, these were somewhat larger. X-ray diffraction indicated the size of the cellulose microfibrils were the same for both types of CWs. PMID:26717549

  6. Comparison of celery (Apium graveolens L.) collenchyma and parenchyma cell wall polysaccharides enabled by solid-state (13)C NMR.

    PubMed

    Zujovic, Zoran; Chen, Da; Melton, Laurence D

    2016-02-01

    Collenchyma cells with their thickened walls are one of specific mechanical support tissues for plants, while parenchyma cells are thin walled and serve multiple functions. The parenchyma tissue is what you enjoy eating, while collenchyma, because of its fibrous nature, is not so attractive. Celery is a useful model for comparing the cell walls (CWs) of the two cell types such as collenchyma and parenchyma. However, to date, the structural characteristics of collenchyma and parenchyma cell walls from the same plant have not been compared. Monosaccharide composition suggested the collenchyma cell walls contained less pectin but more hemicellulose in comparison to parenchyma. High-resolution solid-state NMR spectra of highly mobile pectins revealed that the arabinan signals were more evident in the collenchyma spectrum, while galactan showed a much stronger resonance in the parenchyma spectrum. In addition, methyl esterified and non-esterified galacturonic acid signals were observed in parenchyma CWs, but only the latter one appeared in the collenchyma. The ratio of cellulose surface/interior obtained from CP/MAS spectra for collenchyma suggested the cellulose microfibrils were ~2.4 nm, while in the parenchyma, these were somewhat larger. X-ray diffraction indicated the size of the cellulose microfibrils were the same for both types of CWs.

  7. Develop Solid State Laser Sources for High Resolution Video Projection Systems

    SciTech Connect

    Brickeen, B.K.

    2000-10-24

    Magic Lantern and Honeywell FM and T worked together to develop lower-cost, visible light solid-state laser sources to use in laser projector products. Work included a new family of video displays that use lasers as light sources. The displays would project electronic images up to 15 meters across and provide better resolution and clarity than movie film, up to five times the resolution of the best available computer monitors, up to 20 times the resolution of television, and up to six times the resolution of HDTV displays. The products that could be developed as a result of this CRADA could benefit the economy in many ways, such as: (1) Direct economic impact in the local manufacture and marketing of the units. (2) Direct economic impact in exports and foreign distribution. (3) Influencing the development of other elements of display technology that take advantage of the signals that these elements allow. (4) Increased productivity for engineers, FAA controllers, medical practitioners, and military operatives.

  8. Characterization of pyrogenic organic matter by 2-dimenstional HETeronucleus CORelation solid-state 13C NMR (HETCOR) spectroscopy

    NASA Astrophysics Data System (ADS)

    Knicker, Heike

    2016-04-01

    During the last years, increasing evidences are provided that the common view of charcoal as a polyaromatic network is too much simplified. Experiments with model compounds indicated that it represents a heterogeneous mixture of thermally altered biomacromolecules with N, O and likely also S substitutions as common features. If produced from a N-rich feedstock, the so called black nitrogen (BN) has to be considered as an integral part of the aromatic charcoal network. In order to study this network one-dimensional (1D) solid-state nuclear magnetic resonance (NMR) spectroscopy is often applied. However, this technique suffers from broad resonance lines and low resolution. Applying 2D techniques can help but until recently, this was unfeasible for natural organic matter (NOM) due to sensitivity problems and the high complexity of the material. On the other hand, during the last decade, the development of stronger magnetic field instruments and advanced pulse sequences has put them into reach for NOM research. Although 2D NMR spectroscopy has many different applications, all pulse sequences are based on the introduction of a preparation time during which the magnetization of a spin system is adjusted into a state appropriate to whatever properties are to be detected in the indirect dimension. Then, the spins are allowed to evolve with the given conditions and after their additional manipulation during a mixing period the modulated magnetization is detected. Assembling several 1D spectra with incrementing evolution time creates a data set which is two-dimensional in time (t1, t2). Fourier transformation of both dimensions leads to a 2D contour plot correlating the interactions detected in the indirect dimension t1 with the signals detected in the direct dimension t2. The so called solid-state heteronuclear correlation (HETCOR) NMR spectroscopy represents a 2D technique allows the determination which protons are interacting with which carbons. In the present work this

  9. High-Resolution NMR of Quadrupolar Nuclei in the Solid State

    SciTech Connect

    Gann, Sheryl Lee

    1995-11-30

    This dissertation describes recent developments in solid state nuclear magnetic resonance (NMR), for the most part involving the use of dynamic-angle spinning (DAS) NMR to study quadrupolar nuclei. Chapter 1 introduces some of the basic concepts and theory that will be referred to in later chapters, such as the density operator, product operators, rotations, coherence transfer pathways, phase cycling, and the various nuclear spin interactions, including the quadrupolar interaction. Chapter 2 describes the theory behind motional averaging experiments, including DAS, which is a technique where a sample is spun sequentially about two axis oriented at different angles with respect to the external magnetic field such that the chemical shift and quadrupolar anisotropy are averaged to zero. Work done on various rubidium-87 salts is presented as a demonstration of DAS. Chapter 3 explains how to remove sidebands from DAS and magic-angle spinning (MAS) experiments, which result from the time-dependence of the Hamiltonian under sample spinning conditions, using rotor-synchronized {pi}-pulses. Data from these experiments, known as DAH-180 and MAH-180, respectively, are presented for both rubidium and lead salts. In addition, the applicability of this technique to double rotation (DOR) experiments is discussed. Chapter 4 concerns the addition of cross-polarization to DAS (CPDAS). The theory behind spin locking and cross polarizing quadrupolar nuclei is explained and a method of avoiding the resulting problems by performing cross polarization at 0{sup o} (parallel) with respect to the magnetic field is presented. Experimental results are shown for a sodium-23 compound, sodium pyruvate, and for oxygen-17 labeled L-akmine. In Chapter 5, a method for broadening the Hartmann-Hahn matching condition under MAS, called variable effective field cross-polarization (VEFCI?), is presented, along with experimental work on adamantane and polycarbonate.

  10. Solid state 13C NMR studies of methane dehydroaromatization reaction on Mo/HZSM-5 and W/HZSM-5 catalysts.

    PubMed

    Yang, Jun; Ma, Ding; Deng, Feng; Luo, Qing; Zhang, Mingjin; Bao, Xinhe; Ye, Chaohui

    2002-12-21

    Methane dehydroaromatization on Mo/HZSM-5 and W/HZSM-5 catalysts was studied by solid state 13C NMR spectroscopy, both variation of the state of transition metal component and products such as ethane, benzene, ethene adsorbed on or in zeolite were observed after high temperature (900-1000 K) reaction.

  11. Polydisperse methyl β-cyclodextrin–epichlorohydrin polymers: variable contact time 13C CP-MAS solid-state NMR characterization

    PubMed Central

    Mallard, Isabelle; Baudelet, Davy; Castiglione, Franca; Ferro, Monica; Panzeri, Walter; Ragg, Enzio

    2015-01-01

    Summary The polymerization of partially methylated β-cyclodextrin (CRYSMEB) with epichlorohydrin was carried out in the presence of a known amount of toluene as imprinting agent. Three different preparations (D1, D2 and D3) of imprinted polymers were obtained and characterized by solid-state 13C NMR spectroscopy under cross-polarization magic angle spinning (CP-MAS) conditions. The polymers were prepared by using the same synthetic conditions but with different molar ratios of imprinting agent/monomer, leading to morphologically equivalent materials but with different absorption properties. The main purpose of the work was to find a suitable spectroscopic descriptor accounting for the different imprinting process in three homogeneous polymeric networks. The polymers were characterized by studying the kinetics of the cross-polarization process. This approach is based on variable contact time CP-MAS spectra, referred to as VCP-MAS. The analysis of the VCP-MAS spectra provided two relaxation parameters: T CH (the CP time constant) and T 1ρ (the proton spin-lattice relaxation time in the rotating frame). The results and the analysis presented in the paper pointed out that T CH is sensitive to the imprinting process, showing variations related to the toluene/cyclodextrin molar ratio used for the preparation of the materials. Conversely, the observed values of T 1ρ did not show dramatic variations with the imprinting protocol, but rather confirmed that the three polymers are morphologically similar. Thus the combined use of T CH and T 1ρ can be helpful for the characterization and fine tuning of imprinted polymeric matrices. PMID:26877800

  12. Polydisperse methyl β-cyclodextrin-epichlorohydrin polymers: variable contact time (13)C CP-MAS solid-state NMR characterization.

    PubMed

    Mallard, Isabelle; Baudelet, Davy; Castiglione, Franca; Ferro, Monica; Panzeri, Walter; Ragg, Enzio; Mele, Andrea

    2015-01-01

    The polymerization of partially methylated β-cyclodextrin (CRYSMEB) with epichlorohydrin was carried out in the presence of a known amount of toluene as imprinting agent. Three different preparations (D1, D2 and D3) of imprinted polymers were obtained and characterized by solid-state (13)C NMR spectroscopy under cross-polarization magic angle spinning (CP-MAS) conditions. The polymers were prepared by using the same synthetic conditions but with different molar ratios of imprinting agent/monomer, leading to morphologically equivalent materials but with different absorption properties. The main purpose of the work was to find a suitable spectroscopic descriptor accounting for the different imprinting process in three homogeneous polymeric networks. The polymers were characterized by studying the kinetics of the cross-polarization process. This approach is based on variable contact time CP-MAS spectra, referred to as VCP-MAS. The analysis of the VCP-MAS spectra provided two relaxation parameters: T CH (the CP time constant) and T 1ρ (the proton spin-lattice relaxation time in the rotating frame). The results and the analysis presented in the paper pointed out that T CH is sensitive to the imprinting process, showing variations related to the toluene/cyclodextrin molar ratio used for the preparation of the materials. Conversely, the observed values of T 1ρ did not show dramatic variations with the imprinting protocol, but rather confirmed that the three polymers are morphologically similar. Thus the combined use of T CH and T 1ρ can be helpful for the characterization and fine tuning of imprinted polymeric matrices. PMID:26877800

  13. New room temperature high resolution solid-state detector (CdZnTe) for hard x rays and gamma rays

    NASA Technical Reports Server (NTRS)

    Stewart, Amyelizabeth C.; Desai, Upendra D.

    1993-01-01

    The new CdZnTe high 'Z' material represents a significant improvement in detectors for high energy photons. With the thicknesses available, photons up to 100 keV can be efficiently detected. This material has a wide band gap of 1.5 - 2.2 eV which allows it to operate at room temperature while providing high spectral resolution. Results of resolution evaluations are presented. This detector can be used for high resolution spectral measurements of photons in x-ray and gamma-ray astronomy, offering a significant reduction in the weight, power, and volume of the detector system compared to more conventional detector types such as scintillation counters. In addition, the detector will have the simplicity and reliability of solid-state construction. The CdZnTe detector, as a new development, has not yet been evaluated in space. The Get Away Special program can provide this opportunity.

  14. A high resolution δ13C record in a modern Porites lobata coral: Insights into controls on skeletal δ13C

    NASA Astrophysics Data System (ADS)

    Allison, Nicola; Finch, Adrian A.; EIMF

    2012-05-01

    δ13C was determined at a high spatial resolution by secondary ion mass spectrometry (SIMS) across a 1 year section of a modern Porites lobata coral skeleton from Hawaii. Skeletal δ13C is dominated by large oscillations of 5-7‰ that typically cover skeletal distances equivalent to periods of ˜14-40 days. These variations do not reflect seawater temperature and it is unlikely that they reflect variations in the δ13C of local seawater. We observe no correlation between skeletal δ13C and the pH of the calcification fluid (estimated from previous measurements of skeletal δ11B). We conclude that either the proportion of skeletal carbon derived from metabolic CO2 is not reflected by estimated ECF pH (as the [CO2] in the overlying coral tissue varies) and/or the δ13C composition of the metabolic CO2 is highly variable. We also observe no correlation between skeletal δ13C and previous δ18O SIMS measurements. Variations in skeletal δ13C and δ18O do not have a common timing, providing no evidence that skeletal δ13C and δ18O vary in response to a single factor. This suggests that skeletal δ13C is principally driven by variations in the δ13C composition of metabolic CO2 rather than by the abundance of metabolic CO2, which would also affect skeletal δ18O. The δ13C composition of metabolic CO2 reflects the processes of photosynthesis, heterotrophic feeding and respiration in the overlying coral tissue. Corals catabolise stored lipid reserves to meet energetic demands when photosynthesis conditions are sub-optimal. Variations in the amounts and types of reserves utilised could induce changes in the δ13C composition of metabolic CO2 and the resultant skeleton which are temporally offset from skeletal δ18O records.

  15. Solid state {sup 1}H and {sup 13}C NMR structural investigation of a poly(ethylene oxide) hydrogel

    SciTech Connect

    Badiger, M.V.; Graham, N.B.; Law, R.V.; Snape, C.E.

    1993-12-31

    A cross-linked poly (ethylene oxide)/polyurethane hydrogel cross-linked with 1,2,6 hexane-triol and designated PEG4050/1HT [measured M{sup n} of 4050 for poly (ethylene oxide) glycol (PEG) and a mole ratio of 1:1 for the PEG to the 1,2,6 hexane-triol] has been characterized by high resolution {sup 1}H and {sup 13}C NMR. {sup 1}H thermal (T{sub 1}) and rotating frame (T{sub 1{rho}}) and {sup 13}CT{sub 1} relaxation times were determined for the powdered dry and swollen hydrogel with the standard variants of the cross-polarization pulse sequence which was used in conjunction with magic-angle spinning (MAS). The rotating frame relaxation measurements confirmed that crystalline and amorphous regions were present in the dry hydrogel but showed unabiguously that the crystalline regions are confined to the poly (ethylene oxide) chains, Upon hydration, there is a decrease in the cross polarization efficiency from the enhanced mobility by the poly (ethylene oxide) chains are affected to a much greater extent that the urethane and hexane segments, the characteristic time constant, T{sub CH} increasing by more than order of magnitude compared to no more than a factor of two for the latter. Clearly, the hydration involves hydrogen bonding between the water and principally the oxygens in the poly (ethylene oxide) chains. The {sup 1}H MAS spectra of the dry and hydrated samples confirmed that considerable averaging of the dipolar interactions occurs on hydration to give a well-resolved spectrum.

  16. Early to Middle Jurassic palaeoenvironmental changes: High resolution δ13C and δ18O records from the UK

    NASA Astrophysics Data System (ADS)

    Korte, C.; Hesselbo, S.; Ullmann, C. V.; Ruhl, M.; Thibault, N.

    2013-12-01

    Low-Mg-calcite fossils, such as bivalves, belemnites and brachiopods, and bulk rocks have been extensively utilized to reconstruct past seawater chemistry and paleoenviron¬mental changes. Recent work on major bioevents demonstrated that particularly higher resolution stable isotope records are necessary to reveal short-term paleoenviron¬mental fluctuations and, in addition, to discover its causes. Here we present a new high resolution carbon and oxygen isotope dataset generated from low-Mg-calcite fossils, fossil wood and bulk rocks collected from Early to Middle Jurassic marine successions of the UK. In addition to the well know carbon isotope fluctuations across the Toarcian Oceanic Anoxic Event (OAE), further δ13C perturbations have been obtained from the analyzed samples: (1) a positive trend in the earliest Sinemurian (Conybeari zone), negative excursions in the (2) Sinemurian Bucklandi zone and (3) at the Sinemurian-Pliensbachian boundary (upper raricostatum and lower jamesoni zones), and (4) a positive excursion in the Late Pliensbachian margaritatus zone. At the Sinemurian-Pliensbachian boundary a positive δ18O shift occurs during the negative δ13C excursion, suggesting most likely bottom water cooling as a result of the Early Pliensbachian transgression. Two additional cooling events, (1) in the Late Pliensbachian and (2) during the Aalenian-Bajocian, are discovered by positive oxygen isotope trends. The cool Late Pliensbachian shallow sea-floor is in agreement with previous inference of partial icehouse conditions at that time. More uncertain are potential icehouse interludes during the Aalenian-Bajocian interval. The new isotope datasets show partly a strong similarity between the positions of the global warming/cooling events within transgressive/regressive phases of second-order depositional sequences though the Early to Middle Juras¬sic supporting the idea that second-order depositional se¬quences are a result of eustatic sea-level changes at

  17. High-resolution solid-state NMR study of the occurrence and thermal transformations of silicon-containing species in biomass materials

    SciTech Connect

    Freitas, J.C.C.; Emmerich, F.G.; Bonagamba, T.J.

    2000-03-01

    The occurrence of silicon in two kinds of biomass (rice hulls and endocarp of babassu coconut) and the thermal transformations taking place in these materials under heat treatments are studied here. The authors report also the production, characterization, and study of carbonaceous materials with high SiC content through the carbothermal reduction of silica, using these natural precursors. X-ray diffraction, scanning electron microscopy, and {sup 13}C and {sup 29}Si room temperature high-resolution solid-state NMR measurements are used in the characterization and study of the materials as well as the process of SiC formation. Important conclusions about the nature of silicon in these types of biomass and the effects of heat treatments on the structure of silicon-containing species are derived from the results presented. It is shown that silicon in these materials occurs in two distinct forms: amorphous hydrated silica and organically bound silicon species. The influence of spin-lattice relaxation dynamics on the NMR spectra is discussed, evidencing the role played by the paramagnetic defects produced in the materials through pyrolysis.

  18. Aromatic spectral editing techniques for magic-angle-spinning solid-state NMR spectroscopy of uniformly (13)C-labeled proteins.

    PubMed

    Williams, Jonathan K; Schmidt-Rohr, Klaus; Hong, Mei

    2015-11-01

    The four aromatic amino acids in proteins, namely histidine, phenylalanine, tyrosine, and tryptophan, have strongly overlapping (13)C chemical shift ranges between 100 and 160ppm, and have so far been largely neglected in solid-state NMR determination of protein structures. Yet aromatic residues play important roles in biology through π-π and cation-π interactions. To better resolve and assign aromatic residues' (13)C signals in magic-angle-spinning (MAS) solid-state NMR spectra, we introduce two spectral editing techniques. The first method uses gated (1)H decoupling in a proton-driven spin-diffusion (PDSD) experiment to remove all protonated (13)C signals and retain only non-protonated carbon signals in the aromatic region of the (13)C spectra. The second technique uses chemical shift filters and (1)H-(13)C dipolar dephasing to selectively detect the Cα, Cβ and CO cross peaks of aromatic residues while suppressing the signals of all aliphatic residues. We demonstrate these two techniques on amino acids, a model peptide, and the microcrystalline protein GB1, and show that they significantly simplify the 2D NMR spectra and both reveal and permit the ready assignment of the aromatic residues' signals.

  19. Mechanism of formation of humus coatings on mineral surfaces 3. Composition of adsorbed organic acids from compost leachate on alumina by solid-state 13C NMR

    USGS Publications Warehouse

    Wershaw, R. L.; Llaguno, E.C.; Leenheer, J.A.

    1996-01-01

    The adsorption of compost leachate DOC on alumina is used as a model for elucidation of the mechanism of formation of natural organic coatings on hydrous metal oxide surfaces in soils and sediments. Compost leachate DOC is composed mainly of organic acid molecules. The solid-state 13C NMR spectra of these organic acids indicate that they are very similar in composition to aquatic humic substances. Changes in the solid-state 13C NMR spectra of compost leachate DOC fractions adsorbed on alumina indicate that the DOC molecules are most likely adsorbed on metal oxide surfaces through a combination of polar and hydrophobic interaction mechanisms. This combination of polar and hydrophobic mechanism leads to the formation of bilayer coatings of the leachate molecules on the oxide surfaces.

  20. Analysis of the Fusarium mycotoxin moniliformin in cereal samples using 13C2-moniliformin and high-resolution mass spectrometry.

    PubMed

    von Bargen, Katharina Walburga; Lohrey, Lilia; Cramer, Benedikt; Humpf, Hans-Ulrich

    2012-04-11

    Moniliformin is a mycotoxin produced by fungi of the Fusarium genus and occurs as a contaminant of different cereals worldwide. This study describes the first application of isotopically labeled (13)C(2)-moniliformin for the analysis of moniliformin in cereals. Moniliformin is a small and ionic molecule that forms only a single sensitive fragment ion in the collision cell of a tandem mass spectrometer. Therefore, the methods described in the literature for this kind of instrument observe only a single mass transition and show a relatively poor sensitivity. The use of high-resolution mass spectrometry was described to be a suitable alternative technique for the detection of this compound and was therefore applied in this study. The developed method is based on the use of strong anion exchange columns for cleanup prior to HPLC analysis and has a recovery rate of 75.3%, a limit of detection (LOD) of 0.7 μg/kg, and a limit of quantitation (LOQ) of 2.5 μg/kg. Twenty-three different cereal samples were analyzed for their moniliformin content. Twenty of them showed positive results with levels up to 126 ± 12.2 μg/kg.

  1. High-resolution δ 13C intratooth profiles in bovine enamel: Implications for mineralization pattern and isotopic attenuation

    NASA Astrophysics Data System (ADS)

    Zazzo, Antoine; Balasse, Marie; Patterson, William P.

    2005-07-01

    We present the first high-resolution carbon isotope and carbonate content profiles generated through the thickness of enamel from a steer fed C 3- then C 4-dominant food. Carbonate contents decrease by ˜2 wt% from the enamel surface to the innermost enamel layer, and each carbon isotope profile shows a mixture of enamel portions mineralized over several months. Downward and outward increasing contribution of C 4 food to the enamel δ 13C values reveal two components of the mineralization gradient: a vertical component from the tip of the tooth crown to the neck, and a horizontal component from the enamel-dentine junction to the outer enamel. We use our results to infer mineralization parameters for bovines and to calculate expected isotopic attenuations for an array of environmental inputs and microsampling strategies, using the model developed by Passey and Cerling [ Geochim. Cosmochim. Acta. 66 (2002) 3225-3234]. Although it seems unlikely that any strategy will perfectly isolate discrete time slices, sampling the innermost enamel layer might offer the advantage of significantly reducing the isotope damping that would become independent of the structure of the input signal.

  2. Revisiting spin-lattice relaxation time measurements for dilute spins in high-resolution solid-state NMR spectroscopy.

    PubMed

    Fu, Riqiang; Li, Jun; Cui, Jingyu; Peng, Xinhua

    2016-07-01

    Numerous nuclear magnetic resonance (NMR) measurements of spin-lattice relaxation times (T1S) for dilute spins such as (13)C have led to investigations of the motional dynamics of individual functional groups in solid materials. In this work, we revisit the Solomon equations and analyze how the heteronuclear cross relaxation between the dilute S (e.g. (13)C) and abundant I (e.g. (1)H) spins affects the measured T1S values in solid-state NMR in the absence of (1)H saturation during the recovery time. It is found theoretically that at the beginning of the S spin magnetization recovery, the existence of non-equilibrium I magnetization introduces the heteronuclear cross relaxation effect onto the recovery of the S spin magnetization and confirmed experimentally that such a heteronuclear cross relaxation effect results in the recovery overshoot phenomena for the dilute spins when T1S is on the same order of T1H, leading to inaccurate measurements of the T1S values. Even when T1S is ten times larger than T1H, the heteronuclear cross relaxation effect on the measured T1S values is still noticeable. Furthermore, this cross relaxation effect on recovery trajectory of the S spins can be manipulated and even suppressed by preparing the initial I and S magnetization, so as to obtain the accurate T1S values. A sample of natural abundance l-isoleucine powder has been used to demonstrate the T1S measurements and their corresponding measured T1C values under various experimental conditions. PMID:27187211

  3. Revisiting spin-lattice relaxation time measurements for dilute spins in high-resolution solid-state NMR spectroscopy.

    PubMed

    Fu, Riqiang; Li, Jun; Cui, Jingyu; Peng, Xinhua

    2016-07-01

    Numerous nuclear magnetic resonance (NMR) measurements of spin-lattice relaxation times (T1S) for dilute spins such as (13)C have led to investigations of the motional dynamics of individual functional groups in solid materials. In this work, we revisit the Solomon equations and analyze how the heteronuclear cross relaxation between the dilute S (e.g. (13)C) and abundant I (e.g. (1)H) spins affects the measured T1S values in solid-state NMR in the absence of (1)H saturation during the recovery time. It is found theoretically that at the beginning of the S spin magnetization recovery, the existence of non-equilibrium I magnetization introduces the heteronuclear cross relaxation effect onto the recovery of the S spin magnetization and confirmed experimentally that such a heteronuclear cross relaxation effect results in the recovery overshoot phenomena for the dilute spins when T1S is on the same order of T1H, leading to inaccurate measurements of the T1S values. Even when T1S is ten times larger than T1H, the heteronuclear cross relaxation effect on the measured T1S values is still noticeable. Furthermore, this cross relaxation effect on recovery trajectory of the S spins can be manipulated and even suppressed by preparing the initial I and S magnetization, so as to obtain the accurate T1S values. A sample of natural abundance l-isoleucine powder has been used to demonstrate the T1S measurements and their corresponding measured T1C values under various experimental conditions.

  4. Revisiting spin-lattice relaxation time measurements for dilute spins in high-resolution solid-state NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Fu, Riqiang; Li, Jun; Cui, Jingyu; Peng, Xinhua

    2016-07-01

    Numerous nuclear magnetic resonance (NMR) measurements of spin-lattice relaxation times (T1S) for dilute spins such as 13C have led to investigations of the motional dynamics of individual functional groups in solid materials. In this work, we revisit the Solomon equations and analyze how the heteronuclear cross relaxation between the dilute S (e.g. 13C) and abundant I (e.g. 1H) spins affects the measured T1S values in solid-state NMR in the absence of 1H saturation during the recovery time. It is found theoretically that at the beginning of the S spin magnetization recovery, the existence of non-equilibrium I magnetization introduces the heteronuclear cross relaxation effect onto the recovery of the S spin magnetization and confirmed experimentally that such a heteronuclear cross relaxation effect results in the recovery overshoot phenomena for the dilute spins when T1S is on the same order of T1H, leading to inaccurate measurements of the T1S values. Even when T1S is ten times larger than T1H, the heteronuclear cross relaxation effect on the measured T1S values is still noticeable. Furthermore, this cross relaxation effect on recovery trajectory of the S spins can be manipulated and even suppressed by preparing the initial I and S magnetization, so as to obtain the accurate T1S values. A sample of natural abundance L-isoleucine powder has been used to demonstrate the T1S measurements and their corresponding measured T1C values under various experimental conditions.

  5. The economical synthesis of [2'-(13)C, 1,3-(15)N2]uridine; preliminary conformational studies by solid state NMR.

    PubMed

    Patching, Simon G; Middleton, David A; Henderson, Peter J F; Herbert, Richard B

    2003-06-21

    The synthesis of [2'-(13)C, 1,3-(15)N2]uridine 11 was achieved as follows. An epimeric mixture of D-[1-(13)C]ribose 3 and D-[1-(13)C]arabinose 4 was obtained in excellent yield by condensation of K13CN with D-erythrose 2 using a modification of the Kiliani-Fischer synthesis. Efficient separation of the two aldose epimers was pivotally achieved by a novel ion-exchange (Sm3+) chromatography method. D-[2-(13)C]Ribose 5 was obtained from D-[1-(13)C]arabinose 4 using a Ni(II) diamine complex (nickel chloride plus TEMED). Combination of these procedures in a general cycling manner can lead to the very efficient preparation of specifically labelled 13C-monosaccharides of particular chirality. 15N-labelling was introduced in the preparation of [2'-(13)C, 1,3-(15)N2]uridine 11 via [15N2]urea. Cross polarisation magic angle spinning (CP-MAS) solid-state NMR experiments using rotational echo double resonance (REDOR) were carried out on crystals of the labelled uridine to show that the inter-atomic distance between C-2' and N-1 is closely similar to that calculated from X-ray crystallographic data. The REDOR method will be used now to determine the conformation of bound substrates in the bacterial nucleoside transporters NupC and NupG.

  6. A Boreal high-resolution d13C-carb record of the Albian-Cenomanian transition from NW Germany

    NASA Astrophysics Data System (ADS)

    Bornemann, André; Erbacher, Jochen; Heldt, Matthias; Wilmsen, Markus; Lübke, Nathalie; Heimhofer, Ulrich

    2015-04-01

    The upper Albian of the central NW German Basin is represented by a monotonous (marly) claystone succession of several hundred meters thickness, which becomes siliceous in the topmost Albian (Flammenmergel facies) and shows a gradual increase in carbonate content during the early to middle Cenomanian. Here we present a new ~160-m-thick composite record spanning the uppermost Albian to middle Cenomanian based on two cored drill sites at Anderten, east of Hannover (Germany). We successfully correlated the long-term d13C record to other European reference sections in England (Speeton; Mitchell et al., 1996) and Italy (Contessa - Stoll and Schrag, 2000) as well as to records from the NW German Basin (Wunstorf - Mitchell et al., 1996; Konrad 101 - unpublished). Based on the observed pattern we are able to identify the d13C expression of (1) the Oceanic Anoxic Event 1d, (2) the Albian-Cenomanian boundary, (3) possibly the Lower Cenomanian Event(s) (LCE) and, finally, (4) the Mid-Cenomanian Event (MCE) I close to the top of the record. Chemostratigraphic age assignments are supported by biostratigraphic results. Calcareous nannofossils indicate an extended CC9 zone up to the lowermost CC10 (UC0-UC3 according to Burnett et al., 1998) as indicated by the FAD of Microrhabdulus decoratus at the top. Moreover, previously described influxes of Rotalipora aff. reicheli and the occurrence of the ostracod Neocythere steghausi support a mid-Cenomanian age for the upper part of the studied succession. Due to both moderately well preserved microfossils and high sedimentation rates the drilled succession can be considered as a potential reference for the Albian-Cenomanian transition in the Boreal realm. References: Burnett, J. (1998). Upper Cretaceous Calcareous Nannofossil Biostratigraphy, 132-199. - in: Bown, P. (Ed.) Calcareous Nannofossil Biostratigraphy (Kluwer Academic Publishers). Mitchell, S., Paul, C., Gale, A. (1996). Carbon isotopes and sequence stratigraphy. Geol. Soc

  7. Characterization of a Mixture of CO2 Adsorption Products in Hyperbranched Aminosilica Adsorbents by (13)C Solid-State NMR.

    PubMed

    Moore, Jeremy K; Sakwa-Novak, Miles A; Chaikittisilp, Watcharop; Mehta, Anil K; Conradi, Mark S; Jones, Christopher W; Hayes, Sophia E

    2015-11-17

    Hyperbranched amine polymers (HAS) grown from the mesoporous silica SBA-15 (hereafter "SBA-15-HAS") exhibit large capacities for CO2 adsorption. We have used static in situ and magic-angle spinning (MAS) ex situ (13)C nuclear magnetic resonance (NMR) to examine the adsorption of CO2 by SBA-15-HAS. (13)C NMR distinguishes the signal of gas-phase (13)CO2 from that of the chemisorbed species. HAS polymers possess primary, secondary, and tertiary amines, leading to multiple chemisorption reaction outcomes, including carbamate (RnNCOO(-)), carbamic acid (RnNCOOH), and bicarbonate (HCO3(-)) moieties. Carbamates and bicarbonate fall within a small (13)C chemical shift range (162-166 ppm), and a mixture was observed including carbamic acid and carbamate, the former disappearing upon evacuation of the sample. By examining the (13)C-(14)N dipolar coupling through low-field (B0 = 3 T) (13)C{(1)H} cross-polarization MAS NMR, carbamate is confirmed through splitting of the (13)C resonance. A third species that is either bicarbonate or a second carbamate is evident from bimodal T2 decay times of the ∼163 ppm peak, indicating the presence of two species comprising that single resonance. The mixture of products suggests that (1) the presence of amines and water leads to bicarbonate being present and/or (2) the multiple types of amine sites in HAS permit formation of chemically distinct carbamates.

  8. Probing lipid-cholesterol interactions in DOPC/eSM/Chol and DOPC/DPPC/Chol model lipid rafts with DSC and (13)C solid-state NMR.

    PubMed

    Fritzsching, Keith J; Kim, Jihyun; Holland, Gregory P

    2013-08-01

    The interaction between cholesterol (Chol) and phospholipids in bilayers was investigated for the ternary model lipid rafts, DOPC/eSM/Chol and DOPC/DPPC/Chol, with differential scanning calorimetry (DSC) and (13)C cross polarization magic angle spinning (CP-MAS) solid-state NMR. The enthalpy and transition temperature (Tm) of the Lα liquid crystalline phase transition from DSC was used to probe the thermodynamics of the different lipids in the two systems as a function of Chol content. The main chain (13)C (CH2)n resonance is resolved in the (13)C CP-MAS NMR spectra for the unsaturated (DOPC) and saturated (eSM or DPPC) chain lipid in the ternary lipid raft mixtures. The (13)C chemical shift of this resonance can be used to detect differences in chain ordering and overall interactions with Chol for the different lipid constituents in the ternary systems. The combination of DSC and (13)C CP-MAS NMR results indicate that there is a preferential interaction between SM and Chol below Tm for the DOPC/eSM/Chol system when the Chol content is ≤20mol%. In contrast, no preferential interaction between Chol and DPPC is observed in the DOPC/DPPC/Chol system above or below Tm. Finally, (13)C CP-MAS NMR resolves two Chol environments in the DOPC/eSM/Chol system below Tm at Chol contents >20mol% while, a single Chol environment is observed for DOPC/DPPC/Chol at all compositions.

  9. Solid-state /sup 13/C nuclear magnetic resonance spectroscopy of simultaneously metabolized acetate and phenol in a soil Pseudomonas sp

    SciTech Connect

    Heiman, A.S.; Copper, W.T.

    1987-01-01

    An investigation was made of the concentration-dependent primary and secondary substrate relationships in the simultaneous metabolism of the ubiquitous pollutant phenol and the naturally occurring substrate acetate by a Pseudomonas sp. soil isolate capable of utilizing either substance as a sole source of carbon and energy. In addition to conventional analytical techniques, solid-state /sup 13/C nuclear magnetic resonance spectroscopy was used to follow the cellular distribution of (1-/sup 13/C)acetate in the presence of unlabeled phenol. These results suggest that, when phenol is present as the primary substrate, acetate is preferentially shuttled into fatty acyl chain synthesis, whereas phenol carbon is funnelled into the tricarboxylic acid cycle. Thus, simultaneous use of a xenobiotic compound and a natural substrate apparently does occur, and the relative concentrations of the two substrates do influence the rate and manner in which the compounds are utilized. These results also demonstrate the unique advantage of using solid-state nuclear magnetic resonance techniques combined with /sup 13/C labeling of specific sites in substrates when doing microbial degradation studies. In this work, the entire cellular biomass was examined directly without extensive extraction, fractionation, or isolation of subcellular units; thus, there is no uncertainty about chemical alteration of substrate metabolites as a result of these often harsh treatments.

  10. Solid-state and solution /sup 13/C NMR in the conformational analysis of methadone-hydrochloride and related narcotic analgesics

    SciTech Connect

    Sumner, S.C.J.

    1986-01-01

    Solid state and solution /sup 13/C NMR have been used to study the conformations of the racemic mixtures and single enantiomers of methadone hydrochloride, alpha and beta methadol hydrochloride, and alpha and beta acetylmethadol hydrochloride. The NMR spectra acquired for the compounds as solids, and in polar and nonpolar solvents are compared, in order to determine the conformation of the molecules in solution. To determine the reliability of assigning solution conformations by comparing solution and solid state chemical shift data, three bond coupling constants measured in solution are compared with those calculated from X-ray data. The conformations of the racemic mixture and plus enantiomer of methadone hydrochloride have been shown to be very similar in the solid state, where minor differences in conformation can be seen by comparing NMR spectra obtained for the solids. Also shown is that the molecules of methadone hydrochloride have conformations in polar and in nonpolar solvents which are very similar to the conformation of the molecules in the solid state.

  11. High-resolution FTIR analysis and rotational constants for the ν12 band of ethylene-1-13C (13C12CH4)

    NASA Astrophysics Data System (ADS)

    Gabona, M. G.; Tan, T. L.; Woo, J. Q.

    2014-11-01

    The Fourier transform infrared (FTIR) absorption spectrum of the ν12 fundamental band of ethylene-1-13C (or 13C12CH4) was recorded in the frequency range of 1350-1510 cm-1 with an unapodized resolution of 0.0063 cm-1. The upper state (ν12 = 1) and ground state rotational constants derived in the present analysis cover a wide wavenumber range and high J and Ka (J = 41 and Ka = 14). By assigning and fitting 1602 infrared transitions using Watson's A-reduced Hamiltonian in the Ir representation, upper state (ν12 = 1) constants consisting of three rotational, five quartic and two sextic constants were more accurately determined. The root-mean-square deviation of the fit was 0.00030 cm-1. Ground state rotational constants were also improved from the fit of 808 ground state combination differences (GSCDs) with a root-mean-square deviation of 0.00032 cm-1. The unperturbed A-type ν12 band is centered at 1439.34612(2) cm-1. The inertial defect Δ of 0.05381(8) μÅ2 for the ground state has been derived using the ground state rotational constants obtained from this work.

  12. High Resolution 13C MRI With Hyperpolarized Urea: In Vivo T2 Mapping and 15N Labeling Effects

    PubMed Central

    Reed, Galen D.; von Morze, Cornelius; Bok, Robert; Koelsch, Bertram L.; Van Criekinge, Mark; Smith, Kenneth J.; Shang, Hong; Larson, Peder E. Z.; Kurhanewicz, John; Vigneron, Daniel B.

    2014-01-01

    13C steady state free precession (SSFP) magnetic resonance imaging and effective spin-spin relaxation time (T2) mapping were performed using hyperpolarized [13C] urea and [13C, 15N2] urea injected intravenously in rats. 15N labeling gave large T2 increases both in solution and in vivo due to the elimination of a strong scalar relaxation pathway. The T2 increase was pronounced in the kidney, with [13C, 15N2] urea giving T2 values of 6.3±1.3 s in the cortex and medulla, and 11±2 s in the renal pelvis. The measured T2 in the aorta was 1.3±0.3 s. [13C] urea showed shortened T2 values in the kidney of 0.23±0.03 s compared to 0.28±0.03 s measured in the aorta. The enhanced T2 of [13C, 15N2] urea was utilized to generate large signal enhancement by SSFP acquisitions with flip angles approaching the fully refocused regime. Projection images at 0.94 mm in-plane resolution were acquired with both urea isotopes, with [13C, 15N2] urea giving a greater than four-fold increase in signal-to-noise ratio [13C] over urea. PMID:24235273

  13. 13C CPMAS NMR study of the structure of p- t-butylcalix[4]arene-alkylbenzene clathrates in the solid state

    NASA Astrophysics Data System (ADS)

    Yamanobe, Takeshi; Nakamura, Ichinari; Hibino, Kazunobu; Komoto, Ta-i.; Kurosu, Hiromichi; Ando, Isao; Nakamoto, Yoshiaki; Ishida, Shin-ichiro

    1995-08-01

    The NMR chemical shifts measured by the 13C CPMAS method for clathrates of p- t-butylcalix[4]arenes including mobile alkylbenzenes in the solid state revealed that the alkyl groups of the guest molecules are located in the cavity of p- t-butylcalix[4]arene, depending on the size of the alkyl group. It was found that n-alkylbenzenes are easily incorporated into p- t-butylcalix[4]arene in the order of toluene > ethylbenzene ⩾ n-propylbenzene. For isopropylbenzene, the bulky isopropyl group prevents incorporation into the cavity of the host molecule.

  14. Use of solid-state 13C NMR in structural studies of humic acids and humin from Holocene sediments

    USGS Publications Warehouse

    Hatcher, P.G.; VanderHart, D.L.; Earl, W.L.

    1980-01-01

    13C NMR spectra of solid humic substances in Holocene sediments have been obtained using cross polarization with magic-angle sample spinning techniques. The results demonstrate that this technique holds great promise for structural characterizations of complex macromolecular substances such as humin and humic acids. Quantifiable distinctions can be made between structural features of aquatic and terrestrial humic substances. The aliphatic carbons of the humic substances are dominant components suggestive of input from lipid-like materials. An interesting resemblance is also noted between terrestrial humic acid and humin spectra. ?? 1980.

  15. Solid-State (13)C NMR Delineates the Architectural Design of Biopolymers in Native and Genetically Altered Tomato Fruit Cuticles.

    PubMed

    Chatterjee, Subhasish; Matas, Antonio J; Isaacson, Tal; Kehlet, Cindie; Rose, Jocelyn K C; Stark, Ruth E

    2016-01-11

    Plant cuticles on outer fruit and leaf surfaces are natural macromolecular composites of waxes and polyesters that ensure mechanical integrity and mitigate environmental challenges. They also provide renewable raw materials for cosmetics, packaging, and coatings. To delineate the structural framework and flexibility underlying the versatile functions of cutin biopolymers associated with polysaccharide-rich cell-wall matrices, solid-state NMR spectra and spin relaxation times were measured in a tomato fruit model system, including different developmental stages and surface phenotypes. The hydrophilic-hydrophobic balance of the cutin ensures compatibility with the underlying polysaccharide cell walls; the hydroxy fatty acid structures of outer epidermal cutin also support deposition of hydrophobic waxes and aromatic moieties while promoting the formation of cell-wall cross-links that rigidify and strengthen the cuticle composite during fruit development. Fruit cutin-deficient tomato mutants with compromised microbial resistance exhibit less efficient local and collective biopolymer motions, stiffening their cuticular surfaces and increasing their susceptibility to fracture. PMID:26652188

  16. Elucidating metabolic pathways for amino acid incorporation into dragline spider silk using 13C enrichment and solid state NMR.

    PubMed

    Creager, Melinda S; Izdebski, Thomas; Brooks, Amanda E; Lewis, Randolph V

    2011-07-01

    Spider silk has been evolutionarily optimized for contextual mechanical performance over the last 400 Ma. Despite precisely balanced mechanical properties, which have yet to be reproduced, the underlying molecular architecture of major ampullate spider silk can be simplified being viewed as a versatile block copolymer. Four primary amino acid motifs: polyalanine, (GA)(n), GPGXX, and GGX (X = G,A,S,Q,L,Y) will be considered in this study. Although synthetic mimetics of many of these amino acid motifs have been produced in several biological systems, the source of spider silk's mechanical integrity remains elusive. Mechanical robustness may be a product not only of the amino acid structure but also of the tertiary structure of the silk. Historically, solid state nuclear magnetic resonance (ssNMR) has been used to reveal the crystalline structure of the polyalanine motif; however, limitations in amino acid labeling techniques have obscured the structures of the GGX and GPGXX motifs thought to be responsible for the structural mobility of spider silk. We describe the use of metabolic pathways to label tyrosine for the first time as well as to improve the labeling efficiency of proline. These improved labeling techniques will allow the previously unknown tertiary structures of major ampullate silk to be probed. PMID:21334448

  17. Solid-State (13)C NMR Delineates the Architectural Design of Biopolymers in Native and Genetically Altered Tomato Fruit Cuticles.

    PubMed

    Chatterjee, Subhasish; Matas, Antonio J; Isaacson, Tal; Kehlet, Cindie; Rose, Jocelyn K C; Stark, Ruth E

    2016-01-11

    Plant cuticles on outer fruit and leaf surfaces are natural macromolecular composites of waxes and polyesters that ensure mechanical integrity and mitigate environmental challenges. They also provide renewable raw materials for cosmetics, packaging, and coatings. To delineate the structural framework and flexibility underlying the versatile functions of cutin biopolymers associated with polysaccharide-rich cell-wall matrices, solid-state NMR spectra and spin relaxation times were measured in a tomato fruit model system, including different developmental stages and surface phenotypes. The hydrophilic-hydrophobic balance of the cutin ensures compatibility with the underlying polysaccharide cell walls; the hydroxy fatty acid structures of outer epidermal cutin also support deposition of hydrophobic waxes and aromatic moieties while promoting the formation of cell-wall cross-links that rigidify and strengthen the cuticle composite during fruit development. Fruit cutin-deficient tomato mutants with compromised microbial resistance exhibit less efficient local and collective biopolymer motions, stiffening their cuticular surfaces and increasing their susceptibility to fracture.

  18. High-Resolution Correlation Spectroscopy of 13C Spins Near a Nitrogen-Vacancy Center in Diamond

    NASA Astrophysics Data System (ADS)

    Meriles, Carlos; Laraoui, Abdelghani; Dolde, Florian; Wracthrup, Joerg; Reinhard, Friedemann; Burk, Christian

    2013-03-01

    We use a pulse protocol to monitor the time evolution of the 13C ensemble in the vicinity of a NV center. We observe time correlations in the nuclear spin dynamics that extend over several milliseconds exceeding the color center coherence lifetime by more than an order of magnitude. Upon Fourier transform, we separate 13C spins exhibiting differing coupling constants with a frequency resolution inversely proportional to the NV spin-lattice relaxation time. Further, we use the nuclear spin of the host nitrogen as a quantum register during the correlation interval and demonstrate that hyperfine-shifted resonances in this spectrum can be separated from the bare carbon peak upon proper initialization of the NV. Intriguingly, we find that the amplitude of the correlation signal exhibits a sharp dependence on the applied magnetic field, virtually disappearing below a critical field common to all centers. The value of this transition field can be `tuned' by properly adjusting the timing within our correlation scheme. We discuss these observations in the context of the `quantum-to-classical' transition proposed recently to explain the combined dynamics of the NV spin and the 13C bath at variable magnetic field. A.L. and C.A.M. acknowledge support from Research Corp., the von Humboldt Foundation, and NSF. F.D., C.B., F.R. and J.W. acknowledge support from the EU, the DFG, and the Volkswagen Foundation.

  19. Specific 13C labeling of leucine, valine and isoleucine methyl groups for unambiguous detection of long-range restraints in protein solid-state NMR studies.

    PubMed

    Fasshuber, Hannes Klaus; Demers, Jean-Philippe; Chevelkov, Veniamin; Giller, Karin; Becker, Stefan; Lange, Adam

    2015-03-01

    Here we present an isotopic labeling strategy to easily obtain unambiguous long-range distance restraints in protein solid-state NMR studies. The method is based on the inclusion of two biosynthetic precursors in the bacterial growth medium, α-ketoisovalerate and α-ketobutyrate, leading to the production of leucine, valine and isoleucine residues that are exclusively (13)C labeled on methyl groups. The resulting spectral simplification facilitates the collection of distance restraints, the verification of carbon chemical shift assignments and the measurement of methyl group dynamics. This approach is demonstrated on the type-three secretion system needle of Shigella flexneri, where 49 methyl-methyl and methyl-nitrogen distance restraints including 10 unambiguous long-range distance restraints could be collected. By combining this labeling scheme with ultra-fast MAS and proton detection, the assignment of methyl proton chemical shifts was achieved.

  20. Molecular organization in the native state of woody tissue: Studies of tertiary structure using the Raman microprobe Solid State [sup 13]C NMR and biomimetic tertiary aggregates

    SciTech Connect

    Atalla, R.H.

    1992-01-01

    A number of new approaches to the study of native wood tissue complementary to our earlier Raman spectroscopy including solid state [sup 13]C NMR and X-ray diffractometry. A wide variety of native cellulosic tissues were examined which led to the generation of biomimetic tertiary aggregates which simulate states of aggregation characteristic of cell walls. We have also explored charge transport characteristics of lignified tissue. Our Raman spectroscopic studies have advanced our understanding of key spectral features and confirmed the variability of the patterns of orientation of lignin reported earlier. A major effort was dedicated to assessing the contributions of electronic factors such as conjugation and the resonance Raman effect to enhancement of the spectra features associated with lignin. We have now established a solid foundation for spectral mapping of different regions in cell walls.

  1. Specific 13C labeling of leucine, valine and isoleucine methyl groups for unambiguous detection of long-range restraints in protein solid-state NMR studies

    NASA Astrophysics Data System (ADS)

    Fasshuber, Hannes Klaus; Demers, Jean-Philippe; Chevelkov, Veniamin; Giller, Karin; Becker, Stefan; Lange, Adam

    2015-03-01

    Here we present an isotopic labeling strategy to easily obtain unambiguous long-range distance restraints in protein solid-state NMR studies. The method is based on the inclusion of two biosynthetic precursors in the bacterial growth medium, α-ketoisovalerate and α-ketobutyrate, leading to the production of leucine, valine and isoleucine residues that are exclusively 13C labeled on methyl groups. The resulting spectral simplification facilitates the collection of distance restraints, the verification of carbon chemical shift assignments and the measurement of methyl group dynamics. This approach is demonstrated on the type-three secretion system needle of Shigella flexneri, where 49 methyl-methyl and methyl-nitrogen distance restraints including 10 unambiguous long-range distance restraints could be collected. By combining this labeling scheme with ultra-fast MAS and proton detection, the assignment of methyl proton chemical shifts was achieved.

  2. Solid state structure by X-ray and 13C CP/MAS NMR of new 5-[2-(N,N-dimethylamino)ethoxy]-4,7-dimethylcoumarins

    NASA Astrophysics Data System (ADS)

    Ostrowska, Kinga; Maciejewska, Dorota; Dobrzycki, Łukasz; Socha, Pawel

    2016-05-01

    5-[2-(N,N-dimethylamino)ethoxy]-4,7-dimethylcoumarin (1) and 6-acetyl-5-[2-(N,N-dimethylamino)ethoxy]-4,7-dimethylcoumarin (2), structurally related, were synthesized using both conventional and microwave-assisted approach. An impact of acetyl groups on the molecular structure of coumarin derivatives has been examined. Crystals of 2 were investigated using single crystal and powder X-ray diffraction techniques. Compound 2 crystallizes forming two polymorphs (denoted as 2_1 and 2_2), both belonging to P21/c space group. Both polymorphs are comparably stable and can be formed simultaneously during crystallization process. The solid state structure was also analysed using the fully resolved 13C CP/MAS NMR. The double signals with the intensity ratio of about 1:1 which were observed in the 13C CP/MAS NMR spectrum of compound 1 must arise due to the presence of two conformers of 1. In contrast, NMR spectrum recorded for powder mixture of two polymorphs of compound 2 displays no signal splitting. This is related to structural similarities of molecules in both polymorphs.

  3. Short hydrogen bonds in salts of dicarboxylic acids; structural correlations from solid-state 13C and 2H NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Kalsbeek, Nicoline; Schaumburg, Kjeld; Larsen, Sine

    1993-10-01

    Solid-state 13C and 2H NMR spectra are found to very suitable for characterizing the short Osbnd H...O hydrogen bonds observed in acid salts of dicarboxylic acids. The majority of the investigated compounds are acid salts of malonic, succinic and tartaric acid with monovalent cations derived from alkali metals and small aliphatic amines. They include systems with symmetric and asymmetric hydrogen bonds. Accurate structural information about their geometry is available from low-temperature X-ray diffraction data. The 13C chemical shifts of the C atoms in the different carboxy groups display a linear variation with the absolute difference between the two Csbnd O bond lengths. Theoretical ab initio calculations for model systems showed that the nuclear quadrupole coupling constant NQCC for 2H increases with increasing asymmetry of the hydrogen-bonded system. NQCC values for 2H in the short symmetric hydrogen-bonded systems are in the range 53-59 kHz compared with the larger values of up to 166kHz found in systems with longer asymmetric hydrogen bonds. The 2H NQCC values display a perfect linear dependence on the asymmetry of the hydrogen bond. 2H NQCC decreases with decreasing temperature in the symmetric hydrogen bonds showing that the corresponding potential has a single well.

  4. Tracing bacterial metabolism using multi-nuclear (1H, 2H, and 13C) Solid State NMR: Realizing an Idea Initiated by James Scott

    NASA Astrophysics Data System (ADS)

    Cody, G.; Fogel, M. L.; Jin, K.; Griffen, P.; Steele, A.; Wang, Y.

    2011-12-01

    Approximately 6 years ago, while at the Geophysical Laboratory, James Scott became interested in the application of Solid State Nuclear Magnetic Resonance Spectroscopy to study bacterial metabolism. As often happens, other experiments intervened and the NMR experiments were not pursued. We have revisited Jame's question and find that using a multi-nuclear approach (1H, 2H, and 13C Solid State NMR) on laboratory cell culture has some distinct advantages. Our experiments involved batch cultures of E. coli (MG1655) harvested at stationary phase. In all experiments the growth medium consisted of MOPS medium for enterobacteria, where the substrate is glucose. In one set of experiments, 10 % of the water was D2O; in another 10 % of the glucose was per-deuterated. The control experiment used both water and glucose at natural isotopic abundance. A kill control of dead E. coli immersed in pure D2O for an extended period exhibited no deuterium incorporation. In both deuterium enriched experiments, considerable incorporation of deuterium into E. coli's biomolecular constituents was detected via 2H Solid State NMR. In the case of the D2O enriched experiment, 58 % of the incorporated deuterium is observed in a sharp peak at a frequency of 0.31 ppm, consistent with D incorporation in the cell membrane lipids, the remainder is observed in a broad peak at a higher frequency (centered at 5.4 ppm, but spanning out to beyond 10 ppm) that is consistent with D incorporation into predominantly DNA and RNA. In the case of the D-glucose experiments, 61 % of the deuterium is observed in a sharp resonance peak at 0.34 ppm, also consistent with D incorporation into membrane lipids, the remainder of the D is observed at a broad resonance peak centered at 4.3 ppm, consistent with D enrichment in glycogen. Deuterium abundance in the E. coli cells grown in 10 % D2O is nearly 2X greater than that grown with 10 % D-glucose. Very subtle differences are observed in both the 1H and 13C solid-state

  5. New structural information on a humic acid from two-dimensional 1H-13C correlation solid-state nuclear magnetic resonance.

    PubMed

    Mao, J D; Xing, B; Schmidt-Rohr, K

    2001-05-15

    New information on the chemical structure of a peat humic acid has been obtained using a series of two-dimensional 1H-13C heteronuclear correlation solid-state NMR (HETCOR) experiments with different contact times and with spectral editing by dipolar dephasing and 13C transverse relaxation filtering. Carbon-bonded methyl groups (C-CH3) are found to be near both aliphatic and O-alkyl but not aromatic groups. The spectra prove that most OCH3 groups are connected directly with the aromatic rings, as is typical in lignin. As a result, about one-third of the aromatic C-O groups is not phenolic C-OH but C-OCH3. Both protonated and unprotonated anomeric O-C-O carbons are identified in the one- and two-dimensional spectra. COO groups are found predominantly in OCHn-COO environments, but some are also bonded to aromatic rings and aliphatic groups. All models of humic acids in the literature lack at least some of the features observed here. Compositional heterogeneity was studied by introducing 1H spin diffusion into the HETCOR experiment. Comparison with data for a synthetic polymer, polycarbonate, indicates that the separation between O-alkyl and aromatic groups in the humic acid is less than 1.5 nm. However, transverse 13C relaxation filtering under 1H decoupling reveals heterogeneity on a nanometer scale, with the slow-relaxing component being rich in lignin-like aromatic-C-O-CH3 moieties and poor in COO groups.

  6. The Application of High-Resolution Electron Microscopy to Problems in Solid State Chemistry: The Exploits of a Peeping TEM.

    ERIC Educational Resources Information Center

    Eyring, LeRoy

    1980-01-01

    Describes methods for using the high-resolution electron microscope in conjunction with other tools to reveal the identity and environment of atoms. Problems discussed include the ultimate structure of real crystalline solids including defect structure and the mechanisms of chemical reactions. (CS)

  7. Multidimensional High-Resolution Magic Angle Spinning and Solution-State NMR Characterization of (13)C-labeled Plant Metabolites and Lignocellulose.

    PubMed

    Mori, Tetsuya; Tsuboi, Yuuri; Ishida, Nobuhiro; Nishikubo, Nobuyuki; Demura, Taku; Kikuchi, Jun

    2015-01-01

    Lignocellulose, which includes mainly cellulose, hemicellulose, and lignin, is a potential resource for the production of chemicals and for other applications. For effective production of materials derived from biomass, it is important to characterize the metabolites and polymeric components of the biomass. Nuclear magnetic resonance (NMR) spectroscopy has been used to identify biomass components; however, the NMR spectra of metabolites and lignocellulose components are ambiguously assigned in many cases due to overlapping chemical shift peaks. Using our (13)C-labeling technique in higher plants such as poplar samples, we demonstrated that overlapping peaks could be resolved by three-dimensional NMR experiments to more accurately assign chemical shifts compared with two-dimensional NMR measurements. Metabolites of the (13)C-poplar were measured by high-resolution magic angle spinning NMR spectroscopy, which allows sample analysis without solvent extraction, while lignocellulose components of the (13)C-poplar dissolved in dimethylsulfoxide/pyridine solvent were analyzed by solution-state NMR techniques. Using these methods, we were able to unambiguously assign chemical shifts of small and macromolecular components in (13)C-poplar samples. Furthermore, using samples of less than 5 mg, we could differentiate between two kinds of genes that were overexpressed in poplar samples, which produced clearly modified plant cell wall components. PMID:26143886

  8. Multidimensional High-Resolution Magic Angle Spinning and Solution-State NMR Characterization of 13C-labeled Plant Metabolites and Lignocellulose

    PubMed Central

    Mori, Tetsuya; Tsuboi, Yuuri; Ishida, Nobuhiro; Nishikubo, Nobuyuki; Demura, Taku; Kikuchi, Jun

    2015-01-01

    Lignocellulose, which includes mainly cellulose, hemicellulose, and lignin, is a potential resource for the production of chemicals and for other applications. For effective production of materials derived from biomass, it is important to characterize the metabolites and polymeric components of the biomass. Nuclear magnetic resonance (NMR) spectroscopy has been used to identify biomass components; however, the NMR spectra of metabolites and lignocellulose components are ambiguously assigned in many cases due to overlapping chemical shift peaks. Using our 13C-labeling technique in higher plants such as poplar samples, we demonstrated that overlapping peaks could be resolved by three-dimensional NMR experiments to more accurately assign chemical shifts compared with two-dimensional NMR measurements. Metabolites of the 13C-poplar were measured by high-resolution magic angle spinning NMR spectroscopy, which allows sample analysis without solvent extraction, while lignocellulose components of the 13C-poplar dissolved in dimethylsulfoxide/pyridine solvent were analyzed by solution-state NMR techniques. Using these methods, we were able to unambiguously assign chemical shifts of small and macromolecular components in 13C-poplar samples. Furthermore, using samples of less than 5 mg, we could differentiate between two kinds of genes that were overexpressed in poplar samples, which produced clearly modified plant cell wall components. PMID:26143886

  9. High-resolution {sup 13}C nuclear magnetic resonance evidence of phase transition of Rb,Cs-intercalated single-walled nanotubes

    SciTech Connect

    Bouhrara, M.; Saih, Y.; Waagberg, T.; Goze-Bac, C.; Abou-Hamad, E.

    2011-09-01

    We present 13 C high-resolution magic-angle-turning (MAT) and magic angle spinning nuclear magnetic resonance data of Cs and Rb intercalated single walled carbon nanotubes. We find two distinct phases at different intercalation levels. A simple charge transfer is applicable at low intercalation level. The new phase at high intercalation level is accompanied by a hybridization of alkali (s) orbitals with the carbon (sp2) orbitals of the single walled nanotubes, which indicate bundle surface sites is the most probable alkali site.

  10. High resolution δ 18O and δ 13C records from an annually laminated Scottish stalagmite and relationship with last millennium climate

    NASA Astrophysics Data System (ADS)

    Baker, Andy; Wilson, Rob; Fairchild, Ian J.; Franke, Joerg; Spötl, Christoph; Mattey, Dave; Trouet, Valerie; Fuller, Lisa

    2011-12-01

    High-resolution (annual to decadal) stable isotope records of oxygen and carbon are analysed from an annually laminated stalagmite from NW Scotland. The sample, which was deposited for ~ 1000 yrs until 1996 AD, has previously provided annual resolution climate reconstructions of local rainfall and regional winter North Atlantic Oscillation (wNAO) from variations in annual growth rate. For our stalagmite, for which modern cave monitoring demonstrates that equilibrium deposition is highly likely for δ 18O but not for δ 13C, stalagmite δ 13C originally derives from soil CO 2 produced predominantly by microbial respiration, modified by degassing-related kinetic fractionation, and δ 18O from the composition of infiltrating water during periods of infiltrating water. Both the presence of fluorescent laminae and modern drip-water monitoring demonstrate a drip hydrology that comprises both event and storage components. Over the instrumental period, no correlations between stalagmite or rainfall δ 18O and precipitation amount or temperature are observed, but correlations are observed between rainfall δ 18O and 500 mb height at regional IAEA monitoring stations. However, no correlations are observed between stalagmite δ 18O and instrumental and reconstructed atmospheric circulation, preventing a simple palaeoclimate interpretation of the stalagmite δ 18O proxy. Stalagmite δ 13C has a stronger temporal autocorrelation than δ 18O, indicative of soil mixing of respired CO 2 and significant variability between drips and at different times; correlations with instrumental climate data are therefore not possible. The relative timing of changes in growth rate, δ 18O and δ 13C are discussed, and interpretations compared with other regional climate records. We conclude that, over the last millennium at this mid-latitude cave site, neither δ 18O nor δ 13C cannot be interpreted as a simple paleoclimate proxy.

  11. High resolution solid-state 29Si NMR spectroscopy of silicone gels used to fill breast prostheses.

    PubMed

    Dorne, L; Alikacem, N; Guidoin, R; Auger, M

    1995-10-01

    We have used 29Si solid-state nuclear magnetic resonance (NMR) spectroscopy to study the chemical structure of the silicone gels in virgin and explanted breast prostheses. Despite evidences of alteration in the morphological appearance of the silicone gel inside the breast prosthesis, our results do not reveal changes in the chemical nature and structure of the silicone gels after implantation. In addition to the main 29Si resonance peak at -22.26 ppm that corresponds to the resonance frequency of the D repeat unit of the polysiloxane chains, the high sensitivity of our NMR technique allows the detection of very low concentrations of silicone compounds. Within our experimental detection limit of 0.2%, no signal between -90 ppm and -150 ppm are observed. This indicates that no silica products are present inside the gel of the prostheses. Furthermore, our 29Si NMR spectra indicate differences in the chemical compositions of the silicone gels from different manufacturers.

  12. Chemical and nanometer-scale structure of kerogen and its change during thermal maturation investigated by advanced solid-state 13C NMR spectroscopy

    USGS Publications Warehouse

    Mao, J.; Fang, X.; Lan, Y.; Schimmelmann, A.; Mastalerz, Maria; Xu, L.; Schmidt-Rohr, K.

    2010-01-01

    We have used advanced and quantitative solid-state nuclear magnetic resonance (NMR) techniques to investigate structural changes in a series of type II kerogen samples from the New Albany Shale across a range of maturity (vitrinite reflectance R0 from 0.29% to 1.27%). Specific functional groups such as CH3, CH2, alkyl CH, aromatic CH, aromatic C-O, and other nonprotonated aromatics, as well as "oil prone" and "gas prone" carbons, have been quantified by 13C NMR; atomic H/C and O/C ratios calculated from the NMR data agree with elemental analysis. Relationships between NMR structural parameters and vitrinite reflectance, a proxy for thermal maturity, were evaluated. The aromatic cluster size is probed in terms of the fraction of aromatic carbons that are protonated (???30%) and the average distance of aromatic C from the nearest protons in long-range H-C dephasing, both of which do not increase much with maturation, in spite of a great increase in aromaticity. The aromatic clusters in the most mature sample consist of ???30 carbons, and of ???20 carbons in the least mature samples. Proof of many links between alkyl chains and aromatic rings is provided by short-range and long-range 1H-13C correlation NMR. The alkyl segments provide most H in the samples; even at a carbon aromaticity of 83%, the fraction of aromatic H is only 38%. While aromaticity increases with thermal maturity, most other NMR structural parameters, including the aromatic C-O fractions, decrease. Aromaticity is confirmed as an excellent NMR structural parameter for assessing thermal maturity. In this series of samples, thermal maturation mostly increases aromaticity by reducing the length of the alkyl chains attached to the aromatic cores, not by pronounced growth of the size of the fused aromatic ring clusters. ?? 2010 Elsevier Ltd. All rights reserved.

  13. Multifrequency Ultra-High Resolution Miniature Scanning Microscope Using Microchannel And Solid-State Sensor Technologies And Method For Scanning Samples

    NASA Technical Reports Server (NTRS)

    Wang, Yu (Inventor)

    2006-01-01

    A miniature, ultra-high resolution, and color scanning microscope using microchannel and solid-state technology that does not require focus adjustment. One embodiment includes a source of collimated radiant energy for illuminating a sample, a plurality of narrow angle filters comprising a microchannel structure to permit the passage of only unscattered radiant energy through the microchannels with some portion of the radiant energy entering the microchannels from the sample, a solid-state sensor array attached to the microchannel structure, the microchannels being aligned with an element of the solid-state sensor array, that portion of the radiant energy entering the microchannels parallel to the microchannel walls travels to the sensor element generating an electrical signal from which an image is reconstructed by an external device, and a moving element for movement of the microchannel structure relative to the sample. Discloses a method for scanning samples whereby the sensor array elements trace parallel paths that are arbitrarily close to the parallel paths traced by other elements of the array.

  14. New insights into the structure and chemistry of Titan's tholins via 13C and 15N solid state nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Derenne, S.; Coelho, C.; Anquetil, C.; Szopa, C.; Quirico, E.; Bonhomme, C.

    2012-09-01

    Titan, the largest moon of Saturn, is characterized by a dense atmosphere, mainly composed of N2 (ca. 97 %) and CH4 (ca. 2 %). In the upper atmosphere, methane and nitrogen molecules undergo dissociation under the influence of solar UV radiation and electron impacts, followed by recombination reactions leading to a large variety of organic molecules. Some of these compounds form a thick, orange-coloured haze composed of solid organic aerosols that subsequently fall to the surface or remain in suspension in the atmosphere. To gain insight into the chemical composition and structural nature of these complex organic compounds, analogous materials, termed Titan's tholins, are produced in the laboratory, in particular using plasma discharge in gaseous N2 - CH4 mixtures with similar proportions as in Titan's atmosphere. Titan's tholins have been analysed using a wide variety of techniques which provided a wealth of information about potential functional groups and structural building blocks present within the tholin samples. Taken together, the results converge on a structure based on a CxHyNz chemistry that can contain a variety of C-C, C-N, N-H etc single or multiple bonds. It is now necessary to build on that information to refine the chemical and structural models for the Titan's tholins. Here we used solid state NMR techniques to investigate the carbon and nitrogen bonding environments in a 13C- and 15Nenriched sample.

  15. Early diagenesis of mangrove leaves in a tropical estuary: Bulk chemical characterization using solid-state 13C NMR and elemental analyses

    NASA Astrophysics Data System (ADS)

    Benner, Ronald; Hatcher, Patrick G.; Hedges, John I.

    1990-07-01

    Changes in the chemical composition of mangrove ( Rhizophora mangle) leaves during decomposition in tropical estuarine waters were characterized using solid-state 13C nuclear magnetic resonance (NMR) and elemental (CHNO) analysis. Carbohydrates were the most abundant components of the leaves accounting for about 50 wt% of senescent tissues. Tannins were estimated to account for about 20 wt% of leaf tissues, and lipid components, cutin, and possibly other aliphatic biopolymers in leaf cuticles accounted for about 15 wt%. Carbohydrates were generally less resistant to decomposition than the other constituents and decreased in relative concentration during decomposition. Tannins were of intermediate resistance to decomposition and remained in fairly constant proportion during decomposition. Paraffinic components were very resistant to decomposition and increased in relative concentration as decomposition progressed. Lignin was a minor component of all leaf tissues. Standard methods for the colorimetric determination of tannins (Folin-Dennis reagent) and the gravimetric determination of lignin (Klason lignin) were highly inaccurate when applied to mangrove leaves. The N content of the leaves was particularly dynamic with values ranging from 1.27 wt% in green leaves to 0.65 wt% in senescent yellow leaves attached to trees. During decomposition in the water the N content initially decreased to 0.51 wt% due to leaching, but values steadily increased thereafter to 1.07 wt% in the most degraded leaf samples. The absolute mass of N in the leaves increased during decomposition indicating that N immobilization was occurring as decomposition progressed.

  16. Early diagenesis of mangrove leaves in a tropical estuary: Bulk chemical characterization using solid-state 13C NMR and elemental analyses

    USGS Publications Warehouse

    Benner, R.; Hatcher, P.G.; Hedges, J.I.

    1990-01-01

    Changes in the chemical composition of mangrove (Rhizophora mangle) leaves during decomposition in tropical estuarine waters were characterized using solid-state 13C nuclear magnetic resonance (NMR) and elemental (CHNO) analysis. Carbohydrates were the most abundant components of the leaves accounting for about 50 wt% of senescent tissues. Tannins were estimated to account for about 20 wt% of leaf tissues, and lipid components, cutin, and possibly other aliphatic biopolymers in leaf cuticles accounted for about 15 wt%. Carbohydrates were generally less resistant to decomposition than the other constituents and decreased in relative concentration during decomposition. Tannins were of intermediate resistance to decomposition and remained in fairly constant proportion during decomposition. Paraffinic components were very resistant to decomposition and increased in relative concentration as decomposition progressed. Lignin was a minor component of all leaf tissues. Standard methods for the colorimetric determination of tannins (Folin-Dennis reagent) and the gravimetric determination of lignin (Klason lignin) were highly inaccurate when applied to mangrove leaves. The N content of the leaves was particularly dynamic with values ranging from 1.27 wt% in green leaves to 0.65 wt% in senescent yellow leaves attached to trees. During decomposition in the water the N content initially decreased to 0.51 wt% due to leaching, but values steadily increased thereafter to 1.07 wt% in the most degraded leaf samples. The absolute mass of N in the leaves increased during decomposition indicating that N immobilization was occurring as decomposition progressed. ?? 1990.

  17. Effects of cooking on the cell walls (dietary fiber) of 'Scarlet Warren' winter squash ( Cucurbita maxima ) studied by polysaccharide linkage analysis and solid-state (13)C NMR.

    PubMed

    Ratnayake, R M Sunil; Sims, Ian M; Newman, Roger H; Melton, Laurence D

    2011-07-13

    Cell wall polysaccharides of 'Scarlet Warren' winter squash ( Cucurbita maxima ) were investigated before and after thermal processing. Linkage analysis of polysaccharides was done by gas chromatography coupled to mass spectrometry (GC-MS). The linkage analysis showed the cell wall polysaccharide compositions of raw and cooked squash were similar. The total pectic polysaccharides (galacturonan, rhamnogalacturonan, arabinan, and arabinogalactan) contents of the cell walls of both raw and cooked squash were 39 mol %. The amounts of pectic polysaccharides and xyloglucan in the cell walls of squash showed little alteration on heating. The cellulose content of the raw and cooked cell walls was relatively high at 47 mol %, whereas the xyloglucan content was low at 4 mol %. Solid-state (13)C nuclear magnetic resonance (NMR) spectroscopy techniques were used to examine the molecular motion of the polysaccharides in the cell walls. The mobility of highly flexible galactan depends on the water content of the sample, but no difference was seen between raw and cooked samples. Likewise, the mobility of semimobile pectic polysaccharides was apparently unaltered by cooking. No change was detected in the rigid cellulose microfibrils on cooking.

  18. Solid-state photon-counting hybrid detector array for high-resolution multi-energy X-ray imaging

    NASA Astrophysics Data System (ADS)

    Sia, R.; Kleinfelder, S.; Nagarkar, V. V.

    2011-10-01

    We present in this article the development of a photon-counting, energy-discriminating modular detector based on a pixelated CdZnTe sensor coupled pixel-by-pixel to a novel Digital Pixel Sensor (DPS) readout. The detector is designed for munitions inspection, breast X-ray CT and SPECT/MRI. The current DPS design can also be used to read out other solid-state sensors. The prototype detector is 5.5 mm×5.5 mm in size, and consists of 19×19 pixels on a 250 μm pitch. The DPS is designed in a 0.35 μm process, and every pixel includes a preamplifier, a leakage-current subtraction circuit, an auto-zeroed programmable-gain stage, five comparators, a variable-delay reset circuit and five 16 bit counters. The module is expected to operate at high X-ray fluence exceeding 80 MHz/mm 2, and to improve resolution and contrast in images, while significantly enhancing their signal-to-noise ratio, and assist in identifying material composition via dual-energy imaging. The detector design, fabrication and anticipated performance are discussed.

  19. Exploring Chromophore-Binding Pocket: High-Resolution Solid-State H-C Interfacial Correlation NMR Spectra with Windowed PMLG Scheme.

    PubMed

    Song, Chen; Lang, Christina; Mailliet, Jo; Hughes, Jon; Gärtner, Wolfgang; Matysik, Jörg

    2012-02-01

    High-resolution two-dimensional (2D) (1)H-(13)C heteronuclear correlation spectra are recorded for selective observation of interfacial 3-5.5 Å contacts of the uniformly (13)C-labeled phycocyanobilin (PCB) chromophore with its unlabeled binding pocket. The experiment is based on a medium- and long-distance heteronuclear correlation (MELODI-HETCOR) method. For improving (1)H spectral resolution, a windowed phase-modulated Lee-Goldburg (wPMLG) decoupling scheme is applied during the t(1) evolution period. Our approach allows for identification of chromophore-protein interactions, in particular for elucidation of the hydrogen-bonding networks and charge distributions within the chromophore-binding pocket. The resulting pulse sequence is tested on the cyanobacterial (Cph1) phytochrome sensory module (residues 1-514, Cph1Δ2) containing uniformly (13)C- and (15)N-labeled PCB chromophore (u-[(13)C,(15)N]-PCB-Cph1Δ2) at 17.6 T. PMID:22303079

  20. UV-laser microdissection system - A novel approach for the preparation of high-resolution stable isotope records (δ13C/δ18O) from tree rings

    NASA Astrophysics Data System (ADS)

    Schollaen, Karina; Helle, Gerhard

    2013-04-01

    Intra-annual stable isotope (δ13C and δ18O) studies of tree rings at various incremental resolutions have been attempting to extract valuable seasonal climatic and environmental information or assessing plant ecophysiological processes. For preparing high-resolution isotope samples normally wood segments or cores are mechanically divided in radial direction or cut in tangential direction. After mechanical dissection, wood samples are ground to a fine powder and either cellulose is extracted or bulk wood samples are analyzed. Here, we present a novel approach for the preparation of high-resolution stable isotope records from tree rings using an UV-laser microdissection system. Firstly, tree-ring cellulose is directly extracted from wholewood cross-sections largely leaving the wood anatomical structure intact and saving time as compared to the classical procedure. Secondly, micro-samples from cellulose cross-sections are dissected with an UV-Laser dissection microscope. Tissues of interest from cellulose cross-sections are identified and marked precisely with a screen-pen and dissected via an UV-laser beam. Dissected cellulose segments were automatically collected in capsules and are prepared for stable isotope (δ13C and δ18O) analysis. The new techniques facilitate inter- and intra-annual isotope analysis on tree-ring and open various possibilities for comparisons with wood anatomy in plant eco-physiological studies. We describe the design and the handling of this novel methodology and discuss advantages and constraints given by the example of intra-annual oxygen isotope analysis on tropical trees.

  1. Role of aromatic residues in amyloid fibril formation of human calcitonin by solid-state 13C NMR and molecular dynamics simulation.

    PubMed

    Itoh-Watanabe, Hikari; Kamihira-Ishijima, Miya; Javkhlantugs, Namsrai; Inoue, Ryozo; Itoh, Yuki; Endo, Hiroshi; Tuzi, Satoru; Saitô, Hazime; Ueda, Kazuyoshi; Naito, Akira

    2013-06-21

    Calcitonin (CT) is an amyloid fibril forming peptide. Since salmon calcitonin (sCT), having Leu residues (Leu12, Leu16 or Leu19) instead of Tyr12, Phe16 or Phe19 for human calcitonin (hCT), is known to form the fibrils much slower than hCT, hCTs mutated to Leu residues at the position of 16 (F16L-hCT), 19 (F19L-hCT), and 12, 16 and 19 (TL-hCT) were examined to reveal the role of aromatic side-chains on amyloid fibrillation using solid-state (13)C NMR. The detailed kinetics were analyzed using a two-step reaction mechanism such as nucleation and fibril elongation with the rate constants of k1 and k2, respectively. The k2 values of hCT mutants were significantly slower than that of hCT at a neutral pH, although they were almost the same at an acidic pH. The (13)C chemical shifts of the labeled sites showed that the conformations of monomeric hCT mutants take α-helices as viewed from the Gly10 moiety. The hCT mutants formed fibrils and during the fibril formation, the α-helix around Gly10-Phe22 changed to the β-sheet, and the major structures around Ala26-Ala31 were random coil in the fibrils. Molecular dynamics simulation was performed for the β-sheet system of hCT9-23 and its mutants F16L-hCT9-23, F19L-hCT9-23 and TL-hCT9-23. In one of the stable fibril structures, Phe16 of hCT interacts with Phe19 of the next strand alternatively. In the hCT mutants, lack of Phe16 and Phe19 interaction causes significant instability as compared with the hCT fibril, leading to the reduction of k2 values, as observed experimentally in the hCT mutants at a neutral pH.

  2. A novel ratiometric sensor for the fast detection of palladium species with large red-shift and high resolution both in aqueous solution and solid state.

    PubMed

    Cui, Lei; Zhu, Weiping; Xu, Yufang; Qian, Xuhong

    2013-07-01

    A highly selective fluorescent probe (OHBT) was designed and synthesized by linking the ESIPT fluorophore N-(3-(benzo[d]thiazol-2-yl)-4-(hydroxyphenyl) benzamide) (HBTBC) to the palladium specificity response group, allyl group, for the detection of palladium species in aqueous solution. The allyl group can be hydrolyzed by Pd(0) species through the Pd(0)-catalyzed Tsuji-Trost reaction and thus release the fluorophore HBTBC, which shows two emission bands. The maximum emission spectra originated from the enol and keto forms at 415 and 555 nm respectively and with no overlap, which implies the high resolution of the palladium detection. The palladium species can also be detected by paper strip because of the solid-state fluorescence of probe HOBT catalyzed by palladium. This method was successfully applied in the palladium related Suzuki-Miyaura coupling reaction and the detection limit is lower than 1 μM.

  3. Chemical structures of coal lithotypes before and after CO2 adsorption as investigated by advanced solid-state 13C nuclear magnetic resonance spectroscopy

    USGS Publications Warehouse

    Cao, X.; Mastalerz, Maria; Chappell, M.A.; Miller, L.F.; Li, Y.; Mao, J.

    2011-01-01

    Four lithotypes (vitrain, bright clarain, clarain, and fusain) of a high volatile bituminous Springfield Coal from the Illinois Basin were characterized using advanced solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. The NMR techniques included quantitative direct polarization/magic angle spinning (DP/MAS), cross polarization/total sideband suppression (CP/TOSS), dipolar dephasing, CHn selection, and recoupled C-H long-range dipolar dephasing techniques. The lithotypes that experienced high-pressure CO2 adsorption isotherm analysis were also analyzed to determine possible changes in coal structure as a result of CO2 saturation at high pressure and subsequent evacuation. The main carbon functionalities present in original vitrain, bright clarain, clarain and fusain were aromatic carbons (65.9%-86.1%), nonpolar alkyl groups (9.0%-28.9%), and aromatic C-O carbons (4.1%-9.5%). Among these lithotypes, aromaticity increased in the order of clarain, bright clarain, vitrain, and fusain, whereas the fraction of alkyl carbons decreased in the same order. Fusain was distinct from other three lithotypes in respect to its highest aromatic composition (86.1%) and remarkably small fraction of alkyl carbons (11.0%). The aromatic cluster size in fusain was larger than that in bright clarain. The lithotypes studied responded differently to high pressure CO2 saturation. After exposure to high pressure CO2, vitrain and fusain showed a decrease in aromaticity but an increase in the fraction of alkyl carbons, whereas bright clarain and clarain displayed an increase in aromaticity but a decrease in the fraction of alkyl carbons. Aromatic fused-rings were larger for bright clarain but smaller for fusain in the post-CO2 adsorption samples compared to the original lithotypes. These observations suggested chemical CO2-coal interactions at high pressure and the selectivity of lithotypes in response to CO2 adsorption. ?? 2011 Elsevier B.V.

  4. Solid state 13C NMR analysis of shales and coals from Laramide Basins. Final report, March 1, 1995--March 31, 1996

    SciTech Connect

    Miknis, F.P.; Jiao, Z.S.; Zhao, Hanqing; Surdam, R.C.

    1998-12-31

    This Western Research Institute (WRI) jointly sponsored research (JSR) project augmented and complemented research conducted by the University of Wyoming Institute For Energy Research for the Gas Research Institute. The project, {open_quotes}A New Innovative Exploitation Strategy for Gas Accumulations Within Pressure Compartments,{close_quotes} was a continuation of a project funded by the GRI Pressure Compartmentalization Program that began in 1990. That project, {open_quotes}Analysis of Pressure Chambers and Seals in the Powder River Basin, Wyoming and Montana,{close_quotes} characterized a new class of hydrocarbon traps, the discovery of which can provide an impetus to revitalize the domestic petroleum industry. In support of the UW Institute For Energy Research`s program on pressure compartmentalization, solid-state {sup 13}C NMR measurements were made on sets of shales and coals from different Laramide basins in North America. NMR measurements were made on samples taken from different formations and depths of burial in the Alberta, Bighorn, Denver, San Juan, Washakie, and Wind River basins. The carbon aromaticity determined by NMR was shown to increase with depth of burial and increased maturation. In general, the NMR data were in agreement with other maturational indicators, such as vitrinite reflectance, illite/smectite ratio, and production indices. NMR measurements were also obtained on residues from hydrous pyrolysis experiments on Almond and Lance Formation coals from the Washakie Basin. These data were used in conjunction with mass and elemental balance data to obtain information about the extent of carbon aromatization that occurs during artificial maturation. The data indicated that 41 and 50% of the original aliphatic carbon in the Almond and Lance coals, respectively, aromatized during hydrous pyrolysis.

  5. High resolution photoabsorption spectrum of hexafluoro-1,3-butadiene (1,3-C4F6) as studied by vacuum ultraviolet (VUV) synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Ferreira da Silva, F.; Almeida, D.; Vasekova, E.; Drage, E.; Mason, N. J.; Limão-Vieira, P.

    2012-10-01

    In this Letter we present a high resolution VUV photoabsorption spectrum of hexafluoro-1,3-butadiene (1,3-C4F6), over the wavelength range 113-247 nm (11.0-5.0 eV). The spectrum reveals several new features not previously reported in the literature. The assignment of the observed valence and Rydberg transitions and the associated vibronic series is presented based on our recent ab initio calculations on the vertical excitation energies of C4F6 isomers. The dominant excitation has been assigned to the υ1'(a) Cdbnd C stretching mode in the (51A ← 11A, 3pa ← πa(20a)) and (71A ← 11A, 3pb ← πb(19b)) transitions, with mean energies of 0.201 and 0.188 eV, respectively. The measured absolute photoabsorption cross section has been used to calculate the photolysis lifetime of 1,3-C4F6 in the upper stratosphere (20-50 km).

  6. High-resolution solid-state oxygen-17 NMR of actinide-bearing compounds: an insight into the 5f chemistry.

    PubMed

    Martel, Laura; Magnani, Nicola; Vigier, Jean-Francois; Boshoven, Jacobus; Selfslag, Chris; Farnan, Ian; Griveau, Jean-Christophe; Somers, Joseph; Fanghänel, Thomas

    2014-07-01

    A massive interest has been generated lately by the improvement of solid-state magic-angle spinning (MAS) NMR methods for the study of a broad range of paramagnetic organic and inorganic materials. The open-shell cations at the origin of this paramagnetism can be metals, transition metals, or rare-earth elements. Actinide-bearing compounds and their 5f unpaired electrons remain elusive in this intensive research area due to their well-known high radiotoxicity. A dedicated effort enabling the handling of these highly radioactive materials now allows their analysis using high-resolution MAS NMR (>55 kHz). Here, the study of the local structure of a series of actinide dioxides, namely, ThO2, UO2, NpO2, PuO2, and AmO2, using solid-state (17)O MAS NMR is reported. An important increase of the spectral resolution is found due to the removal of the dipolar broadening proving the efficiency of this technique for structural analysis. The NMR parameters in these systems with numerous and unpaired 5f electrons were interpreted using an empirical approach. Single-ion model calculations were performed for the first time to determine the z component of electron spin on each of the actinide atoms, which is proportional to the shifts. A similar variation thereof was observed only for the heavier actinides of this study.

  7. 17O and 29Si NMR parameters of MgSiO3 phases from high-resolution solid-state NMR spectroscopy and first-principles calculations.

    PubMed

    Ashbrook, Sharon E; Berry, Andrew J; Frost, Daniel J; Gregorovic, Alan; Pickard, Chris J; Readman, Jennifer E; Wimperis, Stephen

    2007-10-31

    The 29Si and 17O NMR parameters of six polymorphs of MgSiO3 were determined through a combination of high-resolution solid-state NMR and first-principles gauge including projector augmented wave (GIPAW) formalism calculations using periodic boundary conditions. MgSiO3 is an important component of the Earth's mantle that undergoes structural changes as a function of pressure and temperature. For the lower pressure polymorphs (ortho-, clino-, and protoenstatite), all oxygen species in the 17O high-resolution triple-quantum magic angle spinning (MAS) NMR spectra were resolved and assigned. These assignments differ from those tentatively suggested in previous work on the basis of empirical experimental correlations. The higher pressure polymorphs of MgSiO3 (majorite, akimotoite, and perovskite) are stabilized at pressures corresponding to the Earth's transition zone and lower mantle, with perovskite being the major constituent at depths >660 km. We present the first 17O NMR data for these materials and confirm previous 29Si work in the literature. The use of high-resolution multiple-quantum MAS (MQMAS) and satellite-transition MAS (STMAS) experiments allows us to resolve distinct oxygen species, and full assignments are suggested. The six polymorphs exhibit a wide variety of structure types, providing an ideal opportunity to consider the variation of NMR parameters (both shielding and quadrupolar) with local structure, including changes in coordination number, local geometry (bond distances and angles), and bonding. For example, we find that, although there is a general correlation of increasing 17O chemical shift with increasing Si-O bond length, the shift observed also depends upon the exact coordination environment.

  8. Acid-base interactions and secondary structures of poly-L-lysine probed by 15N and 13C solid state NMR and Ab initio model calculations.

    PubMed

    Dos, Alexandra; Schimming, Volkmar; Tosoni, Sergio; Limbach, Hans-Heinrich

    2008-12-11

    The interactions of the 15N-labeled amino groups of dry solid poly-L-lysine (PLL) with various halogen and oxygen acids HX and the relation to the secondary structure have been studied using solid-state 15N and 13C CPMAS NMR spectroscopy (CP = cross polarization and MAS = magic angle spinning). For comparison, 15N NMR spectra of an aqueous solution of PLL were measured as a function of pH. In order to understand the effects of protonation and hydration on the 15N chemical shifts of the amino groups, DFT and chemical shielding calculations were performed on isolated methylamine-acid complexes and on periodic halide clusters of the type (CH3NH3(+)X(-))n. The combined experimental and computational results reveal low-field shifts of the amino nitrogens upon interaction with the oxygen acids HX = HF, H2SO4, CH3COOH, (CH3)2POOH, H3PO4, HNO3, and internal carbamic acid formed by reaction of the amino groups with gaseous CO2. Evidence is obtained that only hydrogen-bonded species of the type (Lys-NH2***H-X)n are formed in the absence of water. 15N chemical shifts are maximum when H is located in the hydrogen bond center and then decrease again upon full protonation, as found for aqueous solution at low pH. By contrast, halogen acids interact in a different way. They form internal salts of the type (Lys-NH3(+)X(-))n via the interaction of many acid-base pairs. This salt formation is possible only in the beta-sheet conformation. By contrast, the formation of hydrogen-bonded complexes can occur both in beta-sheet domains as well as in alpha-helical domains. The 15N chemical shifts of the protonated ammonium groups increase when the size of the interacting halogen anions is increased from chloride to iodide and when the number of the interacting anions is increased. Thus, the observed high-field 15N shift of ammonium groups upon hydration is the consequence of replacing interacting halogen atoms by oxygen atoms.

  9. Metal Carbonation of Forsterite in Supercritical CO2 and H2O Using Solid State 29Si, 13C NMR Spectroscop

    SciTech Connect

    Kwak, Ja Hun; Hu, Jian Z.; Hoyt, David W.; Sears, Jesse A.; Wang, Chong M.; Rosso, Kevin M.; Felmy, Andrew R.

    2010-03-11

    Ex situ solid state NMR was used for the first time to study fundamental mineral carbonation processes and reaction extent relevant to geologic carbon sequestration (GCS) using a model silicate mineral forsterite (Mg2SiO4)+supercriticalCO2 with and without H2O. Run conditions were 80 C and 96 atm. 29Si NMR clearly shows that in the absence of CO2, the role of H2O is to hydrolyze surface Mg-O-Si bonds to produce dissolved Mg2+, and mono- and oligomeric hydroxylated silica species. Surface hydrolysis products contain only Q0 (Si(OH)4) and Q1(Si(OH)3OSi) species. An equilibrium between Q0, Q1 and Mg2+ with a saturated concentration equivalent to less than 3.2% of the Mg2SiO4 conversion is obtained at a reaction time of up to 7 days. Using scCO2 without H2O, no reaction is observed within 7 days. Using both scCO2 and H2O, the surface reaction products for silica are mainly Q3 (SiOH(OSi)3) species accompanied by a lesser amount of Q2 (Si(OH)2(OSi)2) and Q4 (Si(OSi)4). However, no Q0 and Q1 were detected, indicating the carbonic acid formation/deprotonation and magnesite (MgCO3) precipitation reactions are faster than the forsterite hydrolysis process. Thus it can be concluded that the Mg2SiO4 hydrolysis process is the rate limiting step of the overall mineral carbonation process. 29Si NMR combined with XRD, TEM, SAED and EDX further reveal that the reaction is a surface reaction with the Mg2SiO4 crystallite in the core and with condensed Q2-Q4 species forming amorphous surface layers. 13C MAS NMR identified a possible reaction intermediate as (MgCO3)4-Mg(OH)2-5H2O. However, at long reaction times only crystallite magnesite MgCO3 products are observed.

  10. High Resolution Laser Spectroscopy of Mg12C12CD, Mg13C13CH and Mg12C_4H

    NASA Astrophysics Data System (ADS)

    Forthomme, D.; Linton, C.; Tokaryk, D. W.; Adam, A. G.; Granger, A. D.

    2010-06-01

    Carbon and magnesium are abundant elements in the interstellar medium, so it is possible that carbon chain molecules containing a magnesium atom may exist in this environment. With this in mind, radical molecules of the form MgC2nH (n = 1,2,3) have been frequent subjects of both experimental and theoretical studies In this presentation we will discuss our high-resolution experiments of the ~A2Π-~X2Σ+ transitions in the isotopologues Mg12C12CD and Mg13C13CH, which complement our earlier investigation of this spectrum in Mg12C12CH^b. The data permit us to determine the lengths of individual bonds to high precision. In addition, we have expanded on previous studies of the ~A2Π-~X2Σ+ transition of Mg12C_4H, conducted at medium resolution. The parameters obtained from our high-resolution spectra are compared with those obtained from theoretical structure calculations. H. Ding, C. Apetrei, L. Chacaga, J. P. Maier, Astrophys. J. 677 (2008) 348-352 D. W. Tokaryk, A. G. Adam, W. S. Hopkins, J. Mol. Spectrosc. 230 (2005) 54-61 D. E. Woon, Chem. Phys. Lett. 274 (1997) 299-305 C. A. Thompson and L. Andrews, J. Am. Chem. Soc. 118 (1996) 10242-10249 X. Guo, J. Zhang, J. Li, L. Jiang, J. Zhang, Chem. Phys 360 (2009) 27-31 E. Chasovskikh, E. B. Jochnowitz, J. P. Maier, J. Phys. Chem. A. 112 (2008) 8686-8689.

  11. Determination of methyl 13C-15N dipolar couplings in peptides and proteins by three-dimensional and four-dimensional magic-angle spinning solid-state NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Helmus, Jonathan J.; Nadaud, Philippe S.; Höfer, Nicole; Jaroniec, Christopher P.

    2008-02-01

    We describe three- and four-dimensional semiconstant-time transferred echo double resonance (SCT-TEDOR) magic-angle spinning solid-state nuclear magnetic resonance (NMR) experiments for the simultaneous measurement of multiple long-range N15-Cmethyl13 dipolar couplings in uniformly C13, N15-enriched peptides and proteins with high resolution and sensitivity. The methods take advantage of C13 spin topologies characteristic of the side-chain methyl groups in amino acids alanine, isoleucine, leucine, methionine, threonine, and valine to encode up to three distinct frequencies (N15-Cmethyl13 dipolar coupling, N15 chemical shift, and Cmethyl13 chemical shift) within a single SCT evolution period of initial duration ˜1/JCC1 (where JCC1≈35Hz, is the one-bond Cmethyl13-C13 J-coupling) while concurrently suppressing the modulation of NMR coherences due to C13-C13 and N15-C13 J-couplings and transverse relaxation. The SCT-TEDOR schemes offer several important advantages over previous methods of this type. First, significant (approximately twofold to threefold) gains in experimental sensitivity can be realized for weak N15-Cmethyl13 dipolar couplings (corresponding to structurally interesting, ˜3.5Å or longer, distances) and typical Cmethyl13 transverse relaxation rates. Second, the entire SCT evolution period can be used for Cmethyl13 and/or N15 frequency encoding, leading to increased spectral resolution with minimal additional coherence decay. Third, the experiments are inherently "methyl selective," which results in simplified NMR spectra and obviates the use of frequency-selective pulses or other spectral filtering techniques. Finally, the N15-C13 cross-peak buildup trajectories are purely dipolar in nature (i.e., not influenced by J-couplings or relaxation), which enables the straightforward extraction of N15-Cmethyl13 distances using an analytical model. The SCT-TEDOR experiments are demonstrated on a uniformly C13, N15-labeled peptide, N-acetyl-valine, and a 56

  12. Cryoprotection of Lipid Membranes for High-Resolution Solid-State NMR Studies of Membrane Peptides and Proteins at Low Temperature

    PubMed Central

    Lee, Myungwoon; Hong, Mei

    2014-01-01

    Solid-state NMR spectra of membrane proteins often show significant line broadening at cryogenic temperatures. Here we investigate the effects of several cryoprotectants to preserve the spectral resolution of lipid membranes and membrane peptides at temperatures down to ~200 K. Trehalose, glycerol, dimethylsulfoxide (DMSO), dimethylformamide (DMF), and polyethylene glycol (PEG), were chosen. These compounds are commonly used in protein crystallography and cryobiology. 13C and 1H MAS spectra of several types of lipid membranes show that DMSO provides the best resolution enhancement over unprotected membranes and also best retards ice formation at low temperature. DMF and PEG-400 show slightly weaker cryoprotection, while glycerol and trehalose neither prevent membrane line broadening nor prevent ice formation under the conditions of our study. Neutral saturated-chain phospholipids are the most amenable to cryoprotection, whereas negatively charged and unsaturated lipids attenuate cryoprotection. 13C-1H dipolar couplings and 31P chemical shift anisotropies indicate that high spectral resolution at low temperature is correlated with stronger immobilization of the lipids at high temperature, indicating that line narrowing results from reduction of the conformational space sampled by the lipid molecules at high temperature. DMSO selectively narrowed the linewidths of the most disordered residues in the influenza M2 transmembrane peptide, while residues that exhibit narrow linewidths in the unprotected membrane are less impacted. A relatively rigid β-hairpin antimicrobial peptide, PG-1, showed a linewidth increase of ~0.5 ppm over a ~70 K temperature drop both with and without cryoprotection. Finally, a short-chain saturated lipid, DLPE, exhibits excellent linewidths, suggesting that it may be a good medium for membrane protein structure determination. The three best cryoprotectants found in this work – DMSO, PEG, and DMF - should be useful for low

  13. A Novel High-Resolution and Sensitivity-Enhanced Three-Dimensional Solid-State NMR Experiment Under Ultrafast Magic Angle Spinning Conditions.

    PubMed

    Zhang, Rongchun; Pandey, Manoj Kumar; Nishiyama, Yusuke; Ramamoorthy, Ayyalusamy

    2015-01-01

    Although magic angle spinning (MAS) solid-state NMR is a powerful technique to obtain atomic-resolution insights into the structure and dynamics of a variety of chemical and biological solids, poor sensitivity has severely limited its applications. In this study, we demonstrate an approach that suitably combines proton-detection, ultrafast-MAS and multiple frequency dimensions to overcome this limitation. With the utilization of proton-proton dipolar recoupling and double quantum (DQ) coherence excitation/reconversion radio-frequency pulses, very high-resolution proton-based 3D NMR spectra that correlate single-quantum (SQ), DQ and SQ coherences of biological solids have been obtained successfully for the first time. The proposed technique requires a very small amount of sample and does not need multiple radio-frequency (RF) channels. It also reveals information about the proximity between a spin and a certain other dipolar-coupled pair of spins in addition to regular SQ/DQ and SQ/SQ correlations. Although (1)H spectral resolution is still limited for densely proton-coupled systems, the 3D technique is valuable to study dilute proton systems, such as zeolites, small molecules, or deuterated samples. We also believe that this new methodology will aid in the design of a plethora of multidimensional NMR techniques and enable high-throughput investigation of an exciting class of solids at atomic-level resolution. PMID:26138791

  14. New opportunities for high-resolution solid-state NMR spectroscopy of oxide materials at 21.1- and 18.8-T fields.

    PubMed

    Stebbins, J; Du, Lin-Shu; Kroeker, S; Neuhoff, P; Rice, D; Frye, J; Jakobsen, H J

    2002-01-01

    We present here high-resolution solid state NMR spectra of several oxide and silicate materials that illustrate the improvements obtainable with very high external fields (18.8 and 21.1 T), with probes capable of tuning to a wide frequency range that allow observations of nuclides from high to low magnetogyric ratio. We discuss 27Al MAS spectra for the zeolite scolecite (CaAl2Si3O10 x 3H2O), 17O MAS data for analcime (NaAlSi2O6 x H2O), calcium monoaluminate (CaAI2O4), and titanite (CaTiSiO5), 39K spin-echo spectra for leucite (KAlSi2O6), microline (KAlSiO8), muscovite (KAl2(AlSi3O10)(OH2) and a potassium aluminosolicate glass, and preliminary 73Ge spin-echo MAS spectra for crystalline and glassy germanium dioxide (GeO2).

  15. Determination of the tautomeric equilibria of pyridoyl benzoyl β-diketones in the liquid and solid state through the use of deuterium isotope effects on (1)H and (13)C NMR chemical shifts and spin coupling constants.

    PubMed

    Hansen, Poul Erik; Borisov, Eugeny V; Lindon, John C

    2015-02-01

    The tautomeric equilibria for 2-pyridoyl-, 3-pyridoyl-, and 4-pyridoyl-benzoyl methane have been investigated using deuterium isotope effects on (1)H and (13)C chemical shifts both in the liquid and the solid state. Equilibria are established both in the liquid and the solid state. In addition, in the solution state the 2-bond and 3-bond J((1)H-(13)C) coupling constants have been used to confirm the equilibrium positions. The isotope effects due to deuteriation at the OH position are shown to be superior to chemical shift in determination of equilibrium positions of these almost symmetrical -pyridoyl-benzoyl methanes. The assignments of the NMR spectra are supported by calculations of the chemical shifts at the DFT level. The equilibrium positions are shown to be different in the liquid and the solid state. In the liquid state the 4-pyridoyl derivative is at the B-form (C-1 is OH), whereas the 2-and 3-pyridoyl derivatives are in the A-form. In the solid state all three compounds are on the B-form. The 4-pyridoyl derivative shows unusual deuterium isotope effects in the solid, which are ascribed to a change of the crystal structure of the deuteriated compound. PMID:24070650

  16. Chemometric Model Development and Comparison of Raman and (13)C Solid-State Nuclear Magnetic Resonance-Chemometric Methods for Quantification of Crystalline/Amorphous Warfarin Sodium Fraction in the Formulations.

    PubMed

    Rahman, Ziyaur; Mohammad, Adil; Akhtar, Sohail; Siddiqui, Akhtar; Korang-Yeboah, Maxwell; Khan, Mansoor A

    2015-08-01

    Warfarin sodium (WS) exists in multiple solid-state forms. The solid-state forms differ in physicochemical properties, and crystalline changes in the drug formulation may influence on the drug product quality and/or clinical performance. It is, therefore, critically important to have a good and reliable analytical method to monitor and quantitate this transformation during stability studies. The aim of the present research was to investigate Raman spectroscopy and solid-state nuclear magnetic resonance ((13)C ssNMR) methods in conjunction with chemometry to quantitate the amorphous and crystalline WS fractions in the drug products. Compositionally identical formulations of amorphous and crystalline WS were prepared, and mixed in various proportions to make 0%-100% amorphous/crystalline sample matrices. Raman and (13)C ssNMR spectra were collected and subjected to partial-least-squares and principle component regressions after mathematical treatment of the data. The model performance parameters such as root-mean-square error of prediction, standard error of prediction, and bias were low for Raman models in comparison to (13)C ssNMR models. Models predicted values of the independent sample matrices match closely with the actual values at high level of crystalline WS. Thus, the developed methods provide means to control and quantitate the WS forms fraction in the drug product.

  17. High-Resolution Solid-State NMR of Anisotropically Mobile Molecules Under Very Low Power 1H Decoupling and Moderate Magic-Angle Spinning

    PubMed Central

    Doherty, Tim; Hong, Mei

    2011-01-01

    We show that for observing high-resolution heteronuclear NMR spectra of anisotropically mobile systems with order parameters less than 0.25, moderate magic-angle spinning (MAS) rates of ∼11 kHz combined with 1H decoupling at 1-2 kHz are sufficient. Broadband decoupling at this low 1H nutation frequency is achieved by composite pulse sequences such as WALTZ-16. We demonstrate this moderate MAS low-power decoupling technique on hydrated POPC lipid membranes, and show that 1 kHz 1H decoupling yields spectra with the same resolution and sensitivity as spectra measured under 50 kHz 1H decoupling when the same acquisition times (∼ 50 ms) are used, but the low-power decoupled spectra give higher resolution and sensitivity when longer acquisition times (> 150 ms) are used, which are not possible with high-power decoupling. The limits of validity of this approach are explored for a range of spinning rates and molecular mobilities using more rigid membrane systems such as POPC/cholesterol mixed bilayers. Finally, we show 15N and 13C spectra of a uniaxially diffusing membrane peptide assembly, the influenza A M2 transmembrane domain, under 11 kHz MAS and 2 kHz 1H decoupling. The peptide 15N and 13C intensities at low power decoupling are 70-80% of the high-power decoupled intensities. Therefore, it is possible to study anisotropically mobile lipids and membrane peptides using liquid-state NMR equipment, relatively large rotors, and moderate MAS frequencies. PMID:19501003

  18. Laccase-catalyzed reactions of 17β-estradiol in the presence of humic acid: Resolved by high-resolution mass spectrometry in combination with (13)C labeling.

    PubMed

    Sun, Kai; Luo, Qi; Gao, Yanzheng; Huang, Qingguo

    2016-02-01

    The widespread presence of estrogens in natural waters poses potential threats to the aquatic organisms and human health. It is known that estrogens undergo enzyme-catalyzed oxidative coupling (ECOC) reactions, which may impact their environmental fate and can be used in wastewater treatment to remove estrogens, but little information is available on how natural organic matter (NOM) may influence 17β-estradiol (E2) transformation in ECOC processes. A series of experiments were conducted to examine the transformation of E2 in aqueous solution containing humic acid (HA) as model NOM by laccase-mediated ECOC reactions. The impact of HA on the reaction behaviors and product distribution is systematically characterized. The presence of HA inhibited the extent of E2 self-coupling in laccase-mediated systems, while promoted cross-coupling between E2 and HA. Reconfiguration of humic molecules was also observed and characterized by changes in absorbance at 275 nm and the ratios between A250 nm/A365 nm. In particular, experiments were conducted with un-labeled E2 mixed with (13)C3-labeled E2 at a set ratio, with the products probed using high-resolution mass spectrometry (HRMS). The high m/z accuracy of HRMS enabled the use of isotope ratio as a tracer to identify possible cross-coupling products between E2 and HA. Such a method combining HRMS and isotope labeling provides a novel means for identification of products in a reaction system involving NOM or other complex matrices. These findings provide a basis for optimization of ECOC reactions for estrogen removal, and also help to understand the environmental transformation of estrogens. PMID:26692517

  19. Quantitative (13)C Solid-State NMR Spectra by Multiple-Contact Cross-polarization for Drug Delivery: From Active Principles to Excipients and Drug Carriers.

    PubMed

    Saïdi, Fadila; Taulelle, Francis; Martineau, Charlotte

    2016-08-01

    In this contribution, we present an analysis of the main parameters influencing the efficiency of the (1)H → (13)C multiple-contact cross-polarization nuclear magnetic resonance (NMR) experiment in the context of solid pharmaceutical materials. Using the optimum experimental conditions, quantitative (13)C NMR spectra are then obtained for porous metal-organic frameworks (potential drug carriers) and for components present in drug formulations (active principle ingredient and excipients, amorphous or crystalline). Finally, we show that mixtures of components can also be quantified with this method and, hence, that it represents an ideal tool for quantification of pharmaceutical formulations by (13)C cross-polarization under magic-angle spinning NMR in the industry as it is robust and easy to set up, much faster than direct (13)C polarization and is efficient for samples at natural abundance. PMID:27372550

  20. Restraints on backbone conformations in solid state NMR studies of uniformly labeled proteins from quantitative amide 15N–15N and carbonyl 13C–13C dipolar recoupling data

    PubMed Central

    Hu, Kan-Nian; Qiang, Wei; Bermejo, Guillermo A.; Schwieters, Charles D.; Tycko, Robert

    2013-01-01

    Recent structural studies of uniformly 15N, 13C-labeled proteins by solid state nuclear magnetic resonance (NMR) rely principally on two sources of structural restraints: (i) restraints on backbone conformation from isotropic 15N and 13C chemical shifts, based on empirical correlations between chemical shifts and backbone torsion angles; (ii) restraints on inter-residue proximities from qualitative measurements of internuclear dipole–dipole couplings, detected as the presence or absence of inter-residue crosspeaks in multidimensional spectra. We show that site-specific dipole–dipole couplings among 15N-labeled backbone amide sites and among 13C-labeled backbone carbonyl sites can be measured quantitatively in uniformly-labeled proteins, using dipolar recoupling techniques that we call 15N-BARE and 13C-BARE (BAckbone REcoupling), and that the resulting data represent a new source of restraints on backbone conformation. 15N-BARE and 13C-BARE data can be incorporated into structural modeling calculations as potential energy surfaces, which are derived from comparisons between experimental 15N and 13C signal decay curves, extracted from crosspeak intensities in series of two-dimensional spectra, with numerical simulations of the 15N-BARE and 13C-BARE measurements. We demonstrate this approach through experiments on microcrystalline, uniformly 15N, 13C-labeled protein GB1. Results for GB1 show that 15N-BARE and 13C-BARE restraints are complementary to restraints from chemical shifts and inter-residue crosspeaks, improving both the precision and the accuracy of calculated structures. PMID:22449573

  1. Hydrogen Bonding Interactions in Amorphous Indomethacin and Its Amorphous Solid Dispersions with Poly(vinylpyrrolidone) and Poly(vinylpyrrolidone-co-vinyl acetate) Studied Using (13)C Solid-State NMR.

    PubMed

    Yuan, Xiaoda; Xiang, Tian-Xiang; Anderson, Bradley D; Munson, Eric J

    2015-12-01

    Hydrogen bonding interactions in amorphous indomethacin and amorphous solid dispersions of indomethacin with poly(vinylpyrrolidone), or PVP, and poly(vinylpyrrolidone-co-vinyl acetate), or PVP/VA, were investigated quantitatively using solid-state NMR spectroscopy. Indomethacin that was (13)C isotopically labeled at the carboxylic acid carbon was used to selectively analyze the carbonyl region of the spectrum. Deconvolution of the carboxylic acid carbon peak revealed that 59% of amorphous indomethacin molecules were hydrogen bonded through carboxylic acid cyclic dimers, 15% were in disordered carboxylic acid chains, 19% were hydrogen bonded through carboxylic acid and amide interactions, and the remaining 7% were free of hydrogen bonds. The standard dimerization enthalpy and entropy of amorphous indomethacin were estimated to be -38 kJ/mol and -91 J/(mol · K), respectively, using polystyrene as the "solvent". Polymers such as PVP and PVP/VA disrupted indomethacin self-interactions and formed hydrogen bonds with the drug. The carboxylic acid dimers were almost completely disrupted with 50% (wt) of PVP or PVP/VA. The fraction of disordered carboxylic acid chains also decreased as the polymer content increased. The solid-state NMR results were compared with molecular dynamics (MD) simulations from the literature. The present work highlights the potential of (13)C solid-state NMR to detect and quantify various hydrogen bonded species in amorphous solid dispersions as well as to serve as an experimental validation of MD simulations.

  2. A straightforward method for stereospecific assignment of val and leu prochiral methyl groups by solid-state NMR: Scrambling in the [2-13C]Glucose labeling scheme

    NASA Astrophysics Data System (ADS)

    Lv, Guohua; Faßhuber, Hannes Klaus; Loquet, Antoine; Demers, Jean-Philippe; Vijayan, Vinesh; Giller, Karin; Becker, Stefan; Lange, Adam

    2013-03-01

    The unambiguous stereospecific assignment of the prochiral methyl groups in Val and Leu plays an important role in the structural investigation of proteins by NMR. Here, we present a straightforward method for their stereospecific solid-state NMR assignment based on [2-13C]Glucose ([2-13C]Glc) as the sole carbon source during protein expression. The approach is fundamentally based on the stereo-selective biosynthetic pathway of Val and Leu, and the co-presence of [2-13C]pyruvate produced mainly by glycolysis and [3-13C]/[1,3-13C]pyruvate most probably formed through scrambling in the pentose phosphate pathway. As a consequence, the isotope spin pairs 13Cβ-13Cγ2 and 13Cα-13Cγ1 in Val, and 13Cγ-13Cδ2 and 13Cβ-13Cδ1 in Leu are obtained. The approach is successfully demonstrated with the stereospecific assignment of the methyl groups of Val and Leu of type 3 secretion system PrgI needles and microcrystalline ubiquitin.

  3. Short- and medium-range order in sodium aluminophosphate glasses: new insights from high-resolution dipolar solid-state NMR spectroscopy.

    PubMed

    Zhang, Long; Eckert, Hellmut

    2006-05-11

    The structures of sodium aluminophosphate glasses prepared by both sol-gel as well as melt-cooling routes have been extensively characterized by high-resolution solid-state 23Na, 27Al, and 31P single and double-resonance NMR techniques, including quantitative connectivity studies by 27Al <--> 31P and 23Na <--> 31P rotational echo double-resonance (REDOR) methods. Studies along four compositional lines, I: (AlPO4)x -(NaPO3)1-x, II: (Na2O)x -(AlPO4)1-x, III: (NaAlO2)x -(NaPO3)1-x, and IV: (Al2O3)x (NaPO3)1-x, reveal that the network structures of those glasses that are accessible by either preparation method are essentially identical. However, the significantly extended glass-forming ranges available by the sol-gel route facilitate exploration of the structure/composition relationships in more detail, revealing a number of interesting universal features throughout the whole glass system. Both short- and medium-range order appear to be controlled strongly by the O/P ratio of the glasses studied: Up to an O/P ratio of 3.5 (pyrophosphate composition), aluminum is predominantly six-coordinated and fully connected to phosphorus (Al(OP)6 sites). In the region 3.5 < or = O/P < or = 4.0, a dramatic structural transformation takes place, leading to the appearance of additional four- and five-coordinated aluminum species whose second coordination spheres are also entirely dominated by phosphorus. The structure of glasses with an O/P ratio of precisely 4.0 (orthophosphate) is dominated by Al(OP)4 units. As the O/P ratio increases beyond 4.0, the average extent of Al-O-P connectivity is decreased significantly. Here, new types of five- and six-coordinated aluminum units, which are only weakly connected to phosphorus, are formed, while the network modifier is attracted mainly by the phosphate units.

  4. Contradictions about Fine Structures in Meson Spectra and Proposed High-Resolution Hadron Spectrometer Using ``Interactive'' Solid-State Hydrogen Target

    NASA Astrophysics Data System (ADS)

    Maglich, Bogdan C.

    2004-08-01

    High resolution has been discouraged in meson spectrometry for 4 decades by the Doctrine of Experiments Incompatible with Theory (DEIT). DEIT a priori rejects narrow hadron resonances on the paradigm that only broad hadron peaks, Γ⩾ 100 MeV, can exist — in spite of the accumulated evidence to the contrary. The facts are: Mesons 2 orders of magnitude narrower than `allowed' for hadrons, have been confirmed; a new one was announced at this conference. Narrow meson structures have been repeatedly reported at high momentum transfer, |t| >0.2, while they are absent at the low transfer, |t| ˜0.01, where 99% of the experiments are performed. Modification of meson mass and width as a function of the density of nuclear matter in which they are produced, have been recently reported. We postulate for meson spectra: (1) Intrinsic (`true') width, Γ, is different from the observable (`apparent') width, Γ': Γ< Γ' (2) Γ of all meson states are narrow and can be observed only at or near the maximum |t| reachable in the reaction, and (3) Γ of all meson resonances are subject to broadening as |t| decreases. Since both Γ' and the production σ are inversely proportional to |t|, most of the observed spectra are produced at the lowest |t| <0.01 and thus the peaks appear broad. We have conceptually designed a novel type hadron spectrometer with an order of magnitude better resolution (0.1 MeV). It would operate at 2 orders of magnitude higher |t| (0.3< |t| <1 (GeV/c)2, than most experiments to date (|t| <0.01). Mesons in the mass region 0.5 solid state hydrogen target' consisting of an array of plastic scintillator fibers, CH; collisions with C are electronically rejected. Missing mass of P is measured in the region of the maximum recoil angle. Story of the suppression by DEIT for 17 years of the observation of a theoretically unexplained narrow peak, which turned out to be ω→2π, and the related

  5. Probing the atomic structure of basaltic melts generated by partial melting of upper mantle peridotite (KLB-1): Insights from high-resolution solid-state NMR study

    NASA Astrophysics Data System (ADS)

    Park, S. Y.; Lee, S. K.

    2015-12-01

    Probing the structural disorder in multi-component silicate glasses and melts with varying composition is essential to reveal the change of macroscopic properties in natural silicate melts. While a number of NMR studies for the structure of multi-component silicate glasses and melts including basaltic and andesitic glasses have been reported (e.g., Park and Lee, Geochim. Cosmochim. Acta, 2012, 80, 125; Park and Lee, Geochim. Cosmochim. Acta, 2014, 26, 42), many challenges still remain. The composition of multi-component basaltic melts vary with temperature, pressure, and melt fraction (Kushiro, Annu. Rev. Earth Planet. Sci., 2001, 71, 107). Especially, the eutectic point (the composition of first melt) of nepheline-forsterite-quartz (the simplest model of basaltic melts) moves with pressure from silica-saturated to highly undersaturated and alkaline melts. The composition of basaltic melts generated by partial melting of upper mantle peridotite (KLB-1, the xenolith from Kilbourne Hole) also vary with pressure. In this study we report experimental results for the effects of composition on the atomic structure of Na2O-MgO-Al2O3-SiO2 (NMAS) glasses in nepheline (NaAlSiO4)-forsterite (Mg2SiO4)-quartz (SiO2) eutectic composition and basaltic glasses generated by partial melting of upper mantle peridotite (KLB-1) using high-resolution multi-nuclear solid-state NMR. The Al-27 3QMAS (triple quantum magic angle spinning) NMR spectra of NMAS glasses in nepheline-forsterite-quartz eutectic composition show only [4]Al. The Al-27 3QMAS NMR spectra of KLB-1 basaltic glasses show mostly [4]Al and a non-negligible fraction of [5]Al. The fraction of [5]Al, the degree of configurational disorder, increases from 0 at XMgO [MgO/(MgO+Al2O3)]=0.55 to ~3% at XMgO=0.79 in KLB-1 basaltic glasses while only [4]Al are observed in nepheline-forsterite-quartz eutectic composition. The current experimental results provide that the fraction of [5]Al abruptly increases by the effect of

  6. Distinguishing tautomerism in the crystal structure of (Z)-N-(5-ethyl-2,3-di-hydro-1,3,4-thiadiazol-2-ylidene) -4-methylbenzenesulfonamide using DFT-D calculations and {sup 13}C solid-state NMR

    SciTech Connect

    Li, Xiaozhou; Bond, Andrew D.; Johansson, Kristoffer E.; Van de Streek, Jacco

    2014-08-01

    The crystal structure of (Z)-N-(5-ethyl-2,3-di-hydro-1,3,4-thiadiazol-2-ylidene) -4-methylbenzenesulfonamide contains an imine tautomer, rather than the previously reported amine tautomer. The tautomers can be distinguished using dispersion-corrected density functional theory calculations and by comparison of calculated and measured {sup 13}C solid-state NMR spectra. The crystal structure of the title compound, C{sub 11}H{sub 13}N{sub 3}O{sub 2}S{sub 2}, has been determined previously on the basis of refinement against laboratory powder X-ray diffraction (PXRD) data, supported by comparison of measured and calculated {sup 13}C solid-state NMR spectra [Hangan et al. (2010 ▶). Acta Cryst. B66, 615–621]. The mol@@ecule is tautomeric, and was reported as an amine tautomer [systematic name: N-(5-ethyl-1,3,4-thia@@diazol-2-yl)-p-toluene@@sulfonamide], rather than the correct imine tautomer. The protonation site on the mol@@ecule’s 1,3,4-thia@@diazole ring is indicated by the inter@@molecular contacts in the crystal structure: N—H⋯O hydrogen bonds are established at the correct site, while the alternative protonation site does not establish any notable inter molecular inter@@actions. The two tautomers provide essentially identical Rietveld fits to laboratory PXRD data, and therefore they cannot be directly distinguished in this way. However, the correct tautomer can be distinguished from the incorrect one by previously reported qu@@anti@@tative criteria based on the extent of structural distortion on optimization of the crystal structure using dispersion-corrected density functional theory (DFT-D) calculations. Calculation of the {sup 13}C SS-NMR spectrum based on the correct imine tautomer also provides considerably better agreement with the measured {sup 13}C SS-NMR spectrum.

  7. Probing the structural disorder of basalts and slab-driven andesite melts: Insights from high-resolution solid-state NMR study

    NASA Astrophysics Data System (ADS)

    Park, S.; Lee, S.

    2012-12-01

    Whereas the structure of multi-component silicate melts has strong implication for the properties of natural silicate melts and relevant magmatic processes in Earth's mantle and crust, little is known about their atomic structures due to lack of suitable experimental probes of multi-component amorphous oxides. Although most of the progress in melt structure has been made for relatively simple binary and ternary silicate glasses, recent advances in high-resolution solid-state NMR (nuclear magnetic resonance) unveil previously unknown structural details of multi-component silicate melts (Lee, S. K. and Sung, S., Chem. Geol., 2008, 256, 326; Lee et al., P. Natl. Acad. Sci. USA., 2011, 108, 6847; Park and Lee, Geochim. Cosmochim. Acta, 2012, 80, 125). In this study we report experimental results on the effects of composition. atomic structure of CaO-MgO-Al_{2} O_{3} -SiO_{2} (CMAS) glasses in diopside (CaMgSi_{2}O_{6}) and Ca-tschermakite (CaAl_{2}SiO_{6}) join and glass in the diopside-anorthite eutectic composition (Di_{64}An_{36})—model systems for basaltic melts—using solid-state NMR. We also report the first high-resolution experimental results on the atomic structure of CaO-MgO-Na_{2}O-Al_{2}O_{3}-SiO_{2} (CMNAS) glasses in diopside and jadeite (NaAlSi_{2}O_{6}) join, and glass in the natural phonolite composition (CaO: MgO: Na_{2}O: K_{2}O: Al_{2}O_{3}: SiO_{2}= 1.4: 8.0: 9.0: 3.8: 13: 64 mol%), a model system for slab driven andesite melts. The Al-27 3QMAS (triple quantum magic angle spinning) NMR spectra of CMAS glasses in diopside-Ca-tschermakite join show predominant ^{[4]}Al and a non-negligible fraction of ^{[5]}Al. Approximately 3.3% of ^{[5]}Al is observed for Di_{64}An_{36} glass. The Al-27 3QMAS NMR spectra of CMNAS glasses in diopside and jadeite join show mostly ^{[4]}Al and a non-negligible fraction of ^{[5]}Al (X_{Diopside}=0.75, the mole fraction of diopside content). While the C_{q} (quadrupolar coupling constant) of ^{[4]}Al for glasses in

  8. (1)H-(13)C-(29)Si triple resonance and REDOR solid-state NMR-A tool to study interactions between biosilica and organic molecules in diatom cell walls.

    PubMed

    Wisser, Dorothea; Brückner, Stephan I; Wisser, Florian M; Althoff-Ospelt, Gerhard; Getzschmann, Jürgen; Kaskel, Stefan; Brunner, Eike

    2015-01-01

    Triple resonance solid-state NMR experiments using the spin combination (1)H-(13)C-(29)Si are still rarely found in the literature. This is due to the low natural abundance of the two heteronuclei. Such experiments are, however, increasingly important to study hybrid materials such as biosilica and others. A suitable model substance, ideally labeled with both (13)C and (29)Si, is thus very useful to optimize the experiments before applying them to studies of more complex samples such as biosilica. Tetraphenoxysilane could be synthesized in an easy, two-step synthesis including double isotope labelling. Using tetraphenoxysilane, we established a (1)H-(13)C-(29)Si double CP-based HETCOR experiment and applied it to diatom biosilica from the diatom species Thalassiosira pseudonana. Furthermore, we carried out (1)H-(13)C{(29)Si} CP-REDOR experiments in order to estimate the distance between the organic matrix and the biosilica. Our experiments on diatom biosilica strongly indicate a close contact between polyamine-containing parts of the organic matrix and the silica. This corroborates the assumption that the organic matrix is essential for the control of the cell wall formation.

  9. Residue specific hydration of primary cell wall potato pectin identified by solid-state 13C single-pulse MAS and CP/MAS NMR spectroscopy.

    PubMed

    Larsen, Flemming H; Byg, Inge; Damager, Iben; Diaz, Jerome; Engelsen, Søren B; Ulvskov, Peter

    2011-05-01

    Hydration of rhamnogalacturonan-I (RG-I) derived from potato cell wall was analyzed by (13)C single-pulse (SP) magic-angle-spinning (MAS) and (13)C cross-polarization (CP) MAS nuclear magnetic resonance (NMR) and supported by (2)H SP/MAS NMR experiments. The study shows that the arabinan side chains hydrate more readily than the galactan side chains and suggests that the overall hydration properties can be controlled by modifying the ratio of these side chains. Enzymatic modification of native (NA) RG-I provided samples with reduced content of arabinan (sample DA), galactan (sample DG), or both side chains (sample DB). Results of these samples suggested that hydration properties were determined by the length and character of the side chains. NA and DA exhibited similar hydration characteristics, whereas DG and DB were difficult to hydrate because of the less hydrophilic properties of the rhamnose-galacturonic acid (Rha-GalA) backbone in RG-I. Potential food ingredient uses of RG-I by tailoring of its structure are discussed.

  10. Development of qualitative and quantitative analysis methods in pharmaceutical application with new selective signal excitation methods for 13 C solid-state nuclear magnetic resonance using 1 H T1rho relaxation time.

    PubMed

    Nasu, Mamiko; Nemoto, Takayuki; Mimura, Hisashi; Sako, Kazuhiro

    2013-01-01

    Most pharmaceutical drug substances and excipients in formulations exist in a crystalline or amorphous form, and an understanding of their state during manufacture and storage is critically important, particularly in formulated products. Carbon 13 solid-state nuclear magnetic resonance (NMR) spectroscopy is useful for studying the chemical and physical state of pharmaceutical solids in a formulated product. We developed two new selective signal excitation methods in (13) C solid-state NMR to extract the spectrum of a target component from such a mixture. These methods were based on equalization of the proton relaxation time in a single domain via rapid intraproton spin diffusion and the difference in proton spin-lattice relaxation time in the rotating frame ((1) H T1rho) of individual components in the mixture. Introduction of simple pulse sequences to one-dimensional experiments reduced data acquisition time and increased flexibility. We then demonstrated these methods in a commercially available drug and in a mixture of two saccharides, in which the (13) C signals of the target components were selectively excited, and showed them to be applicable to the quantitative analysis of individual components in solid mixtures, such as formulated products, polymorphic mixtures, or mixtures of crystalline and amorphous phases. PMID:23147444

  11. Structural Modification and Bioavailability of Starch Components As Related to the Extent of Maillard Reaction: An Enzymatic Degradation and a Solid-State (13)C CPMAS NMR Study.

    PubMed

    Pizzoferrato; Paci; Rotilio

    1998-02-16

    Starch and starch components, amylose and amylopectin, from potato, have been studied in order to understand the modifications, induced by different levels of the Maillard reaction occurring in the presence of amino acids (L-lysine in this study), in the macromolecular structure and digestibility. Structural characterization was performed by (13)C CPMAS NMR, and differences in the bioavailability of these polymers were studied by enzymatic degradation kinetics. Results obtained reveal that changes are induced by the Maillard reaction, whose occurrence has been verified and measured by the furosine (epsilon-N-2-furoylmethyl-L-lysine) evaluation, on the macromolecular structure of starchy materials and on their enzymatic susceptibility. Lysine seems to act as a disordering agent; a loss of crystallinity is evident for starch and amylopectin and, in particular, for amylose. Finally, within the same sample, as the lysine concentration increases, the polymer digestibility decreases, confirming that structural organization is not the only determinant of starch digestibility. PMID:10554259

  12. Structure and disorder in iron-bearing sodium silicate glasses and melts: High-resolution 29Si and 17O solid-state NMR study

    NASA Astrophysics Data System (ADS)

    Kim, H.; Lee, S.

    2012-12-01

    Understanding of the effect of iron content on the structure (Si coordination environment and the degree of polymerization) of iron-bearing silicate melts and glasses is essential for studying their macroscopic properties and diverse geological processes in Earth's interior. Although the recent advances in high-resolution solid-state NMR techniques provide detailed structural information of a diverse iron-free oxide glasses with varying composition (e.g., Lee, P. Natl. Acad. Sci. USA., 2011, 108, 6847; Lee and Sung, Chem. Geol., 2008, 256, 326; Park and Lee, Geochim. Cosmochim. Acta, 2012, 80, 125; Lee et al., Phys. Rev., 103, 095501, 2009), their application to iron-bearing silicate glasses has a limited usefulness in resolving atomic configurations due to the effect of paramagnetic cation (i.e., Fe) on the NMR spectra. Here, we report the first ^{29}Si and ^{17}O NMR spectra for sodium-iron silicate glasses with varying iron content (Na_{2}O-Fe_{2}O_{3}-SiO_{2} glasses, up to 34.60 wt% Fe_{2}O_{3}), revealing previously unknown details of iron-induced changes in structure and disorder. While signal intensity decreases and peak width increases exponentially with increasing iron content [=Fe_{2}O_{3}/(Na_{2}O+Fe_{2}O_{3})], ^{29}Si MAS NMR spectra for sodium-iron silicate glasses present the slight peak shift and an asymmetrical peak broadening toward higher Q^{n} species with increasing iron content. This result implies an increase in the degree of polymerization with increasing iron content. Additionally, ^{29}Si spin-relaxation time (T_{1}) for the glasses decreases with increasing of iron content by several orders of magnitude. ^{17}O 3QMAS NMR spectra for the glasses show well-resolved non-bridging oxygen (NBO, Na-O-Si) and bridging oxygen (BO, Si-O-Si) even at relatively high iron content, providing the first direct experimental estimation of the degree of polymerization. In sodium-iron silicate glasses, the fraction of NBO decreases with increasing iron

  13. Rovibrational constants of the ground state and v8 = 1 state of 13C2HD3 by high-resolution FTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Ng, L. L.; Tan, T. L.

    2016-06-01

    The Fourier transform infrared (FTIR) spectrum of the c-type ν8 band of 13C2HD3 was recorded for the first time at a unapodized resolution of 0.0063 cm-1 in the wavenumber region of 830-1000 cm-1. Through the fitting of a total of 1057 assigned infrared transitions using Watson's A-reduced Hamiltonian in the Ir representation, rovibrational constants for the upper state (v8 = 1) up to five quartic centrifugal distortion terms were derived for the first time with a root-mean-square (rms) deviation of 0.00073 cm-1. The band center of ν8 of 13C2HD3 was found to be 913.011021(55) cm-1. Ground state rovibrational constants up to five quartic terms of 13C2HD3 were also determined from a fit of 453 ground state combination-differences from the present infrared measurements with an rms deviation of 0.00072 cm-1 for the first time. The uncertainty of the measured infrared lines was estimated to be ±0.0012 cm-1. From the ground state rotational constants, the inertial defect of 13C2HD3 was calculated to be 0.06973(16) uÅ2, showing the high planarity of the molecule.

  14. Use of solid waste for chemical stabilization: Adsorption isotherms and {sup 13}C solid-state NMR study of hazardous organic compounds sorbed on coal fly ash

    SciTech Connect

    Netzel, D.A.; Lane, D.C.; Rovani, J.F.; Cox, J.D.; Clark, J.A.; Miknis, F.P.

    1993-09-01

    Adsorption of hazardous organic compounds on the Dave Johnston plant fly ash is described. Fly ash from Dave Johnston and Laramie River power plants were characterized using elemental, x-ray, and {sup 29}Si NMR; the Dave Johnston (DJ) fly ash had higher quartz contents, while the Laramie River fly ash had more monomeric silicate anions. Adsorption data for hydroaromatics and chlorobenzenes indicate that the adsorption capacity of DJ coal fly ash is much less than that of activated carbon by a factor of >3000; but it is needed to confirm that solid-gas and solid-liquid equilibrium isotherms can indeed be compared. However, for pyridine, pentachlorophenol, naphthalene, and 1,1,2,2-tetrachloroethane, the DJ fly ash appears to adsorb these compounds nearly as well as activated carbon. {sup 13}C NMR was used to study the adsorption of hazardous org. cpds on coal fly ash; the nuclear spin relaxation times often were very long, resulting in long experimental times to obtain a spectrum. Using a jumbo probe, low concentrations of some hazardous org. cpds could be detected; for pentachlorophenol adsorbed onto fly ash, the chemical shift of the phenolic carbon was changed. Use of NMR to study the adsorption needs further study.

  15. Comparisons of sorption of aquatic humic matter by DAX-8 and XAD-8 resins from solid-state (13)C NMR spectroscopy's point of view.

    PubMed

    Peuravuori, J; Ingman, P; Pihlaja, K; Koivikko, R

    2001-10-31

    Aquatic humic solutes were separated in parallel by the non-ionic macroporous DAX-8 and XAD-8 resins from four different fresh water sources. On average, the sorptive power of the DAX-8 resin does not differ systematically from that of the XAD-8 resin. The DAX-8 resin seems to have more precise column characteristics compared with the XAD-8 resin. There was no significant difference between the major elemental compositions of the parallel humic-solute bulks obtained by these two resins. According to the (13)C NMR spectroscopy the content and quality of aliphatic carbons, especially those representing terminal methyl groups or methylene carbons, were the most systematic and powerful discriminating factors between the humic extracts obtained by these two resins. Generally speaking the DAX-8 and XAD-8 resins seem to isolate humic-solute bulks almost equally, although the content of aliphatics is slightly greater for the former, producing mixtures with similar structural compositions for general purposes. The structural composition and quantity of the humic-solute mixture isolable with a weakly basic DEAE-cellulose anion exchange resin differs partially from any humic fraction obtained by non-ionic sorbing solids. The environmental impact was also visible on the quality of the structural fine-chemistry of the different humic isolates obtained both by the DAX-8 and XAD-8 resins. PMID:18968420

  16. High-Resolution Spectroscopy of the A^1Π(v'=0-10)-X^1Σ^+(v''=0) Bands in 13C18O

    NASA Astrophysics Data System (ADS)

    Lemaire, Jean Louis; Eidelsberg, Michele; Heays, Alan; Gavilan, Lisseth; Federman, Steven; Stark, Glenn; Lyons, James R.; de Oliveira, Nelson; Joyeux, Denis

    2016-06-01

    Ultraviolet spectrographs on space-borne astronomical facilities are used to study CO photochemistry primarily through observations of the A-X Fourth Positive Band System. Absorption from 12C16O, 13C16O, 12C18O, and 12C17O in diffuse interstellar clouds has been detected to date. While the necessary spectroscopic data are available to identify the isotopologues, measurements of oscillator strengths only exist for the most abundant variant, 12C16O. In our ongoing experiments on the DESIRS beam-line at the SOLEIL Synchrotron, we are acquiring the necessary data on oscillator strengths and term values for other isotopologues. Here we present our latest results involving A-X bands in 13C18O.

  17. High-resolution FTIR spectroscopic analysis of the ν11 and ν2 + ν7 bands of 13C2D4

    NASA Astrophysics Data System (ADS)

    Gabona, M. G.; Tan, T. L.

    2016-06-01

    The FTIR spectrum of the ν11 band of 13C2D4 was recorded at a resolution of 0.0063 cm-1 in the 2130-2250 cm-1 region. This band was perturbed by the unobserved ν2 + ν7 band. By fitting 862 infrared transitions for the ν11 band with a rms deviation of 0.0024 cm-1 using a Watson's A-reduced Hamiltonian in the Ir representation including a Coriolis coupling constant, the rovibrational constants for the ν11 = 1 state and three rotational constants for the ν2 = ν7 = 1 state of 13C2D4 were derived for the first time. The band centers of ν11 and ν2 + ν7 were determined to be 2193.75982(25) cm-1 and 2184.613(11) cm-1 respectively.

  18. Analysis of the Rotational Structure in the High-Resolution Infrared Spectrum of trans-Hexatriene-1-13C1; a Semiexperimental Equilibrium Structure for the C6 Backbone for trans-Hexatriene

    SciTech Connect

    Craig, Norman C.; Tian, Hengfeng; Blake, Thomas A.

    2012-03-29

    trans-Hexatriene-1-13C1 (tHTE-1-13C1) has been synthesized, and its high-resolution (0.0015 cm-1) infrared spectrum has been recorded. The rotational structure in the C-type bands for v26 at 1011 cm-1 and v30 at 894 cm-1 has been analyzed. To the 1458 ground state combination differences from these bands, ground state rotational constants were fitted to a Watson-type Hamiltonian to give A0 = 0.8728202(9), B0 = 0.0435868(4), and C0 = 0.0415314(2) cm-1. Upper state rotational constants for the v30 band were also fitted. Predictions of the ground state rotational constants for t-HTE-1-13C1 from a B3LYP/cc-pVTZ model with scale factors based on the normal species were in excellent agreement with observations. Similar good agreement was found between predicted and observed ground state rotational constants for the three 13C1 isotopologues of cis-hexatriene (cHTE), as determined from microwave spectroscopy. Equilibrium rotational constants for tHTE and its three 13C1 isotopologues, of which two were predicted, were used to find a semiexperimental equilibrium structure for the C6 backbone of tHTE. This structure shows increased structural effects of pi-electron delocalization in comparison with butadiene.

  19. Solid-state 13C NMR study of banana liquid crystals - 3: Alkyl-tail-group packing environments of an acute-angle bent-core molecule in the hexagonal columnar and cubic phases

    NASA Astrophysics Data System (ADS)

    Kurosu, Hiromichi; Endo, Yumi; Kimura, Saori; Hashimoto, Tomoko; Harada, Motoi; Lee, Eun-Woo; Sone, Masato; Watanabe, Junji; Kang, Sungmin

    2016-02-01

    Solid-state 13C nuclear magnetic resonance (NMR) measurements were performed on the hexagonal columnar and cubic phases of an acute-angle banana-shaped molecule, N(1,7)-S30. In the hexagonal columnar phase, three peaks appear at the NMR chemical shifts assigned to the internal methylene carbons of alkyl tails, indicating that the two alkyl tails have different packing structures, and one of the tails has two different conformations within a single molecule. Combined cross-polarization/magic-angle spinning and pulse saturation transfer/magic-angle spinning measurements show that one of the alkyl chains is located inside and the other is located outside the columnar structure. In the cubic phase, pulse saturation transfer/magic-angle spinning measurement shows that only one peak appears at the NMR chemical shifts assigned to the internal methylene carbons of alkyl tails, indicating that both of the alkyl chains are located outside the cubic structure.

  20. Investigation of chloromethane complexes of cryptophane‐A analogue with butoxy groups using 13C NMR in the solid state and solution along with single crystal X‐ray diffraction

    PubMed Central

    Steiner, Emilie; Mathew, Renny; Zimmermann, Iwan; Brotin, Thierry; Edén, Mattias

    2015-01-01

    Host‐guest complexes between cryptophane‐A analogue with butoxy groups (cryptophane‐But) and chloromethanes (chloroform, dichloromethane) were investigated in the solid state by means of magic‐angle spinning 13C NMR spectroscopy. The separated local fields method with 13C‐1H dipolar recoupling was used to determine the residual dipolar coupling for the guest molecules encaged in the host cavity. In the case of chloroform guest, the residual dipolar interaction was estimated to be about 19 kHz, consistent with a strongly restricted mobility of the guest in the cavity, while no residual interaction was observed for encaged dichloromethane. In order to rationalize this unexpected result, we performed single crystal X‐ray diffraction studies, which confirmed that both guest molecules indeed were present inside the cryptophane cavity, with a certain level of disorder. To improve the insight in the dynamics, we performed a 13C NMR spin‐lattice relaxation study for the dichloromethane guest in solution. The system was characterized by chemical exchange, which was slow on the chemical shift time scale but fast with respect to the relaxation rates. Despite these disadvantageous conditions, we demonstrated that the data could be analyzed and that the results were consistent with an isotropic reorientation of dichloromethane within the cryptophane cavity. Copyright © 2015 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd. PMID:26095611

  1. High resolution infrared and Raman spectra of {sup 13}C{sup 12}CD{sub 2}: The CD stretching fundamentals and associated combination and hot bands

    SciTech Connect

    Di Lonardo, G.; Fusina, L. Canè, E.; Tamassia, F.; Martínez, R. Z.; Bermejo, D.

    2015-09-07

    Infrared and Raman spectra of mono {sup 13}C fully deuterated acetylene, {sup 13}C{sup 12}CD{sub 2}, have been recorded and analysed to obtain detailed information on the C—D stretching fundamentals and associated combination, overtone, and hot bands. Infrared spectra were recorded at an instrumental resolution ranging between 0.006 and 0.01 cm{sup −1} in the region 1800–7800 cm{sup −1}. Sixty new bands involving the ν{sub 1} and ν{sub 3} C—D stretching modes also associated with the ν{sub 4} and ν{sub 5} bending vibrations have been observed and analysed. In total, 5881 transitions have been assigned in the investigated spectral region. In addition, the Q branch of the ν{sub 1} fundamental was recorded using inverse Raman spectroscopy, with an instrumental resolution of about 0.003 cm{sup −1}. The transitions relative to each stretching mode, i.e., the fundamental band, its first overtone, and associated hot and combination bands involving bending states with υ{sub 4} + υ{sub 5} up to 2 were fitted simultaneously. The usual Hamiltonian appropriate to a linear molecule, including vibration and rotation l-type and the Darling–Dennison interaction between υ{sub 4} = 2 and υ{sub 5} = 2 levels associated with the stretching states, was adopted for the analysis. The standard deviation for each global fit is ≤0.0004 cm{sup −1}, of the same order of magnitude of the measurement precision. Slightly improved parameters for the bending and the ν{sub 2} manifold have been also determined. Precise values of spectroscopic parameters deperturbed from the resonance interactions have been obtained. They provide quantitative information on the anharmonic character of the potential energy surface, which can be useful, in addition to those reported in the literature, for the determination of a general anharmonic force field for the molecule. Finally, the obtained values of the Darling–Dennison constants can be valuable for understanding energy flows

  2. Analysis of the rotational structure in the high-resolution infrared spectrum of trans-hexatriene-1-13C1: a semiexperimental equilibrium structure for the C6 backbone of trans-hexatriene.

    PubMed

    Craig, Norman C; Tian, Hengfeng; Blake, Thomas A

    2012-03-29

    trans-Hexatriene-1-(13)C(1) (tHTE-1-(13)C(1)) has been synthesized, and its high-resolution (0.0015 cm(-1)) infrared spectrum has been recorded. The rotational structure in the C-type bands for ν(26) at 1011 cm(-1) and ν(30) at 894 cm(-1) has been analyzed. To the 1458 ground state combination differences from these bands, ground state rotational constants were fitted to a Watson-type Hamiltonian to give A(0) = 0.8728202(9), B(0) = 0.0435868(4), and C(0) = 0.0415314(2) cm(-1). Upper state rotational constants for the ν(30) band were also fitted. Predictions of the ground state rotational constants for tHTE-1-(13)C(1) from a B3LYP/cc-pVTZ model with scale factors based on the normal species were in excellent agreement with observations. Similar good agreement was found between predicted and observed ground state rotational constants for the three (13)C(1) isotopologues of cis-hexatriene, as determined from microwave spectroscopy. Equilibrium rotational constants for tHTE and its three (13)C(1) isotopologues, of which two were predicted, were used to find a semiexperimental equilibrium structure for the C(6) backbone of tHTE. This structure shows increased structural effects of π-electron delocalization in comparison with butadiene and some differences from the cis isomer of HTE. Structures predicted with the MP2/cc-pVTZ model are also compared.

  3. High-Resolution Stimulated Raman Spectroscopy and Analysis of ν_2 and ν_3 Bands of of 13C_2H_4 Using the D2h Top Data System

    NASA Astrophysics Data System (ADS)

    Alkadrou, Abdulsamee; Rotger, Maud; Bermejo, Dionisio; Domenech, Jose Luis; Boudon, Vincent

    2016-06-01

    High resolution stimulated Raman spectra of 13C_2H_4 in the regions of the ν_2 and ν_3 Raman active modes have been recorded at at two temperatures (145 and 296 K) based on the quasi continuous-wave (cw) stimulated Raman spectrometer at Instituto de Estructura de la Materia (CSIC) in Madrid. A tensorial formalism adapted to X2Y4 planar asymmetric tops with D2h symmetry has been developed in Dijon and a program suite called D2hTDS (now part of the XTDS/SPVIEW spectroscopic software was proposed to calculate their high-resolution spectra. The effective Hamiltonian operator, involving a polyad structure, and transition moment (dipole moment and polarizability) operators can be systematically expanded to carry out global analyses of many rovibrational bands. A total of 103 and 51 lines corresponding to ν_2 and ν_3 Raman active modes have been assigned and fitted in frequency with a global root mean square deviation of 0.54 × 10-3 cm-1 and 0.36 × 10-3 cm-1, respectively. The figures below shows the stimulated Raman spectrum of the ν_2 and ν_3 bands of 13C_2H_4, compared to the simulation at 296 K. Raballand W, Rotger M, Boudon V, Loëte M. J Mol Spectrosc 2003;217:239-48. Wenger Ch, Boudon V, Rotger M, Champion JP, Sanzharov M. J Mol Spectrosc 2008;251:102-13.

  4. Experimental (X-ray, (13)C CP/MAS NMR, IR, RS, INS, THz) and Solid-State DFT Study on (1:1) Co-Crystal of Bromanilic Acid and 2,6-Dimethylpyrazine.

    PubMed

    Łuczyńska, Katarzyna; Drużbicki, Kacper; Lyczko, Krzysztof; Dobrowolski, Jan Cz

    2015-06-01

    A combined structural, vibrational spectroscopy, and solid-state DFT study of the hydrogen-bonded complex of bromanilic acid with 2,6-dimethylpyrazine is reported. The crystallographic structure was determined by means of low-temperature single-crystal X-ray diffraction, which reveals the molecular units in their native protonation states, forming one-dimensional infinite nets of moderate-strength O···H-N hydrogen bonds. The nature of the crystallographic forces, stabilizing the studied structure, has been drawn by employing the noncovalent interactions analysis. It was found that, in addition to the hydrogen bonding, the intermolecular forces are dominated by stacking interactions and C-H···O contacts. The thermal and calorimetric analysis was employed to probe stability of the crystal phase. The structural analysis was further supported by a computationally assisted (13)C CP/MAS NMR study, providing a complete assignment of the recorded resonances. The vibrational dynamics was explored by combining the optical (IR, Raman, TDs-THz) and inelastic neutron scattering (INS) spectroscopy techniques with the state-of-the-art solid-state density functional theory (DFT) computations. Despite the quasi-harmonic approximation assumed throughout the study, an excellent agreement between the theoretical and experimental data was achieved over the entire spectral range, allowing for a deep and possibly thorough understanding of the vibrational characteristics of the system. Particularly, the significant influence of the long-range dipole coupling on the IR spectrum has been revealed. On the basis of a wealth of information gathered, the recent implementation of a dispersion-corrected linear-response scheme has been extensively examined.

  5. Transformation of 17β-estradiol in humic acid solution by ε-MnO2 nanorods as probed by high-resolution mass spectrometry combined with (13)C labeling.

    PubMed

    Sun, Kai; Liang, Shangtao; Kang, Fuxing; Gao, Yanzheng; Huang, Qingguo

    2016-07-01

    Steroidal estrogens (SEs), widespread in aquatic systems, have a potential to disrupt the endocrine system of wildlife species and humans. In our experiments, the performance of ε-MnO2 nanorods in transforming 17β-estradiol (E2) was investigated, and the effect of humic acid (HA) on the reaction behaviors was systematically characterized. Reconfiguration of humic molecules was also investigated by high-performance size exclusion chromatography (HPSEC). Results indicated that ε-MnO2 nanomaterials ensured efficient removal of E2 from the aqueous solution. The presence of HA hindered the transformation of E2, while enhanced the cross-coupling between E2 and humic molecules. In particular, we used a mixture of un-labeled E2 and (13)C3-labeled E2 at a 1: 1 set ratio (w/w) to probe the reaction products via high-resolution mass spectrometry (HRMS). The combination of HRMS and (13)C3-labeling revealed the intermediate products including estrone (E1), and hydroxylated, quinone-like, and ring-opened species, as well as E2 dimer and trimer. More importantly, possible cross-coupling products between E2 and HA were also identified. A reaction mechanism including two-electron oxidation and single-electron oxidation was proposed. The applied analytical approach using HRMS along with (13)C3-labeling for reaction-product identification is crucial to understanding the role of HA in the transformation of SEs.

  6. Transformation of 17β-estradiol in humic acid solution by ε-MnO2 nanorods as probed by high-resolution mass spectrometry combined with (13)C labeling.

    PubMed

    Sun, Kai; Liang, Shangtao; Kang, Fuxing; Gao, Yanzheng; Huang, Qingguo

    2016-07-01

    Steroidal estrogens (SEs), widespread in aquatic systems, have a potential to disrupt the endocrine system of wildlife species and humans. In our experiments, the performance of ε-MnO2 nanorods in transforming 17β-estradiol (E2) was investigated, and the effect of humic acid (HA) on the reaction behaviors was systematically characterized. Reconfiguration of humic molecules was also investigated by high-performance size exclusion chromatography (HPSEC). Results indicated that ε-MnO2 nanomaterials ensured efficient removal of E2 from the aqueous solution. The presence of HA hindered the transformation of E2, while enhanced the cross-coupling between E2 and humic molecules. In particular, we used a mixture of un-labeled E2 and (13)C3-labeled E2 at a 1: 1 set ratio (w/w) to probe the reaction products via high-resolution mass spectrometry (HRMS). The combination of HRMS and (13)C3-labeling revealed the intermediate products including estrone (E1), and hydroxylated, quinone-like, and ring-opened species, as well as E2 dimer and trimer. More importantly, possible cross-coupling products between E2 and HA were also identified. A reaction mechanism including two-electron oxidation and single-electron oxidation was proposed. The applied analytical approach using HRMS along with (13)C3-labeling for reaction-product identification is crucial to understanding the role of HA in the transformation of SEs. PMID:27086077

  7. High-resolution structure of the Shigella type-III secretion needle by solid-state NMR and cryo-electron microscopy

    NASA Astrophysics Data System (ADS)

    Demers, Jean-Philippe; Habenstein, Birgit; Loquet, Antoine; Kumar Vasa, Suresh; Giller, Karin; Becker, Stefan; Baker, David; Lange, Adam; Sgourakis, Nikolaos G.

    2014-09-01

    We introduce a general hybrid approach for determining the structures of supramolecular assemblies. Cryo-electron microscopy (cryo-EM) data define the overall envelope of the assembly and rigid-body orientation of the subunits while solid-state nuclear magnetic resonance (ssNMR) chemical shifts and distance constraints define the local secondary structure, protein fold and inter-subunit interactions. Finally, Rosetta structure calculations provide a general framework to integrate the different sources of structural information. Combining a 7.7-Å cryo-EM density map and 996 ssNMR distance constraints, the structure of the type-III secretion system needle of Shigella flexneri is determined to a precision of 0.4 Å. The calculated structures are cross-validated using an independent data set of 691 ssNMR constraints and scanning transmission electron microscopy measurements. The hybrid model resolves the conformation of the non-conserved N terminus, which occupies a protrusion in the cryo-EM density, and reveals conserved pore residues forming a continuous pattern of electrostatic interactions, thereby suggesting a mechanism for effector protein translocation.

  8. High-resolution structure of the Shigella type-III secretion needle by solid-state NMR and cryo-electron microscopy.

    PubMed

    Demers, Jean-Philippe; Habenstein, Birgit; Loquet, Antoine; Kumar Vasa, Suresh; Giller, Karin; Becker, Stefan; Baker, David; Lange, Adam; Sgourakis, Nikolaos G

    2014-01-01

    We introduce a general hybrid approach for determining the structures of supramolecular assemblies. Cryo-electron microscopy (cryo-EM) data define the overall envelope of the assembly and rigid-body orientation of the subunits while solid-state nuclear magnetic resonance (ssNMR) chemical shifts and distance constraints define the local secondary structure, protein fold and inter-subunit interactions. Finally, Rosetta structure calculations provide a general framework to integrate the different sources of structural information. Combining a 7.7-Å cryo-EM density map and 996 ssNMR distance constraints, the structure of the type-III secretion system needle of Shigella flexneri is determined to a precision of 0.4 Å. The calculated structures are cross-validated using an independent data set of 691 ssNMR constraints and scanning transmission electron microscopy measurements. The hybrid model resolves the conformation of the non-conserved N terminus, which occupies a protrusion in the cryo-EM density, and reveals conserved pore residues forming a continuous pattern of electrostatic interactions, thereby suggesting a mechanism for effector protein translocation. PMID:25264107

  9. Powder X-ray diffraction, infrared and 13C NMR spectroscopic studies of the homologous series of some solid-state zinc(II) and sodium(I) n-alkanoates

    NASA Astrophysics Data System (ADS)

    Nelson, Peter N.; Taylor, Richard A.

    2015-03-01

    A comparative study of the room temperature molecular packing and lattice structures for the homologous series of zinc(II) and sodium(I) n-alkanoates adduced from Fourier transform infrared and solid-state 13C NMR spectroscopic data in conjunction with X-ray powder diffraction measurements is carried out. For zinc carboxylates, metal-carboxyl bonding is via asymmetric bridging bidentate coordination whilst for the sodium adducts, coordination is via asymmetric chelating bidentate bonding. All compounds are packed in a monoclinic crystal system. Furthermore, the fully extended all-trans hydrocarbon chains are arranged as lamellar bilayers. For zinc compounds, there is bilayer overlap, for long chain adducts (nc > 8) but not for sodium compounds where methyl groups from opposing layers in the lamellar are only closely packed. Additionally, the hydrocarbon chains are extended along the a-axis of the unit cell for zinc compounds whilst for sodium carboxylates they are extended along the c-axis. These packing differences are responsible for different levels of Van der Waals effects in the lattices of these two series of compounds, hence, observed odd-even alternation is different. The significant difference in lattice packing observed for these two series of compounds is proposed to be due to the difference in metal-carboxyl coordination mode, arising from the different electronic structure of the central metal ions.

  10. Examination of the structure in solid state of amino analogs of 4,4‧-[1,5-pentanediylbis(oxy)]bisbenzonitrile by means of X-ray diffraction, 13C CP/MAS NMR, and theoretical calculations

    NASA Astrophysics Data System (ADS)

    Maciejewska, Dorota; Wolska, Irena; Żabiński, Jerzy

    2008-05-01

    A single crystal of X-ray diffraction structures is presented for 4,4'-[1,5-(3-oxapentanediylbis(amino))]bisbenzonitrile 2 and 4,4'-[1,5-( N-methyl-3-azapentane-diylbis(oxy))]bisbenzonitrile 3. The molecular structures of these derivatives differ especially in conformations of the central linker: in 2 this linker adopts a trans/ gauche conformation, whereas in 3 - a fully extended conformation. The N atoms in various positions of the aliphatic linker change dramatically the molecular packing mode of both bisnitriles. But in both cases the nitrile groups take part in intermolecular hydrogen bonds: a type of N sbnd H···N in 2 and of C sbnd H···N in 3. Various conformations of both molecules were reflected in 13C CP/MAS NMR spectra in solid state as single and double resonance patterns for 2 and 3, respectively. A preliminary anticancer assay against 60 cell lines of 3 reveals strong growth inhibition of leukemia, melanoma, and renal cancer cells.

  11. Model-free estimation of the effective correlation time for C-H bond reorientation in amphiphilic bilayers: 1H-13C solid-state NMR and MD simulations

    NASA Astrophysics Data System (ADS)

    Ferreira, Tiago Mendes; Ollila, O. H. Samuli; Pigliapochi, Roberta; Dabkowska, Aleksandra P.; Topgaard, Daniel

    2015-01-01

    Molecular dynamics (MD) simulations give atomically detailed information on structure and dynamics in amphiphilic bilayer systems on timescales up to about 1 μs. The reorientational dynamics of the C-H bonds is conventionally verified by measurements of 13C or 2H nuclear magnetic resonance (NMR) longitudinal relaxation rates R1, which are more sensitive to motional processes with correlation times close to the inverse Larmor frequency, typically around 1-10 ns on standard NMR instrumentation, and are thus less sensitive to the 10-1000 ns timescale motion that can be observed in the MD simulations. We propose an experimental procedure for atomically resolved model-free estimation of the C-H bond effective reorientational correlation time τe, which includes contributions from the entire range of all-atom MD timescales and that can be calculated directly from the MD trajectories. The approach is based on measurements of 13C R1 and R1ρ relaxation rates, as well as 1H-13C dipolar couplings, and is applicable to anisotropic liquid crystalline lipid or surfactant systems using a conventional solid-state NMR spectrometer and samples with natural isotopic composition. The procedure is demonstrated on a fully hydrated lamellar phase of 1-palmitoyl-2-oleoyl-phosphatidylcholine, yielding values of τe from 0.1 ns for the methyl groups in the choline moiety and at the end of the acyl chains to 3 ns for the g1 methylene group of the glycerol backbone. MD simulations performed with a widely used united-atom force-field reproduce the τe-profile of the major part of the acyl chains but underestimate the dynamics of the glycerol backbone and adjacent molecular segments. The measurement of experimental τe-profiles can be used to study subtle effects on C-H bond reorientational motions in anisotropic liquid crystals, as well as to validate the C-H bond reorientation dynamics predicted in MD simulations of amphiphilic bilayers such as lipid membranes.

  12. 13 C solid-state NMR study of the 13 C-labeled peptide, (E)8 GGLGGQGAG(A)6 GGAGQGGYGG as a model for the local structure of Nephila clavipes dragline silk (MaSp1) before and after spinning.

    PubMed

    Yazawa, Koji; Yamaguchi, Erika; Knight, David; Asakura, Tetsuo

    2012-06-01

    We prepared the water soluble model peptide, (E)(8) GGLGGQGAG(A)(6) GGAGQGGYGG, to throw light on the local structure of spidroin 1 (MaSpl) protein in spider dragline silk of Nephila clavipes before and after spinning. Solution (13) C NMR showed that the conformation of the peptide in aqueous solution was essentially random coil. Solid-state NMR was used to follow conformation-dependent (13) C chemical shifts in (13) C selectively labeled versions of the peptide. The peptide lyophilized from an aqueous solution at neutral pH (hereafter referred to as "without acid treatment)"was used to mimic the state of the spidroin stored in the spider's silk gland while the peptide precipitated from the acidic solution ("with acid treatment") was used to simulate the role of acid treatment in inducing conformation change in the natural spinning process. In without acid treatment, the fraction of random coil conformation was lowest in the N-terminal region (residues 15-18) when compared with the C-terminus. The conformational change produced by the acid treatment occurred in the sequence, G(15) AG(A)(6) GGAG(27), interposed between pairs of Gly residues pairs, Gly(12,13), and Gly(29,30). The acid treated peptide showed a remarkable decrease in the fraction of random coil conformation from A(20) to A(23) in the poly-Ala region when compared with the peptide without acid treatment. These observations taken together suggest that the peptide can be used as a model for studying the localization of the conformation change in spider silk fibroin in the natural spinning and the role of acid treatment in this process.

  13. High Resolution δ18O and δ13C Records of AMS 14C Dated Stalagmites From Jinlun and Yilingyan Caves in Guangxi, China: Climate Variability and Controlling Factors in the Monsoonal Region During the Past 2300 Years

    NASA Astrophysics Data System (ADS)

    Li, H. C.; Lien, W. Y.; Mii, H. S.; Jiang, G. H.; Chou, C. Y.; Chou, P. J.

    2015-12-01

    Jinlun Cave in Mashan County and Yilingyan Cave in Wuming County are ~120km and ~60km north of Nanning in Guangxi Province under influence of both Indian Monsoon and North Western Pacific Monsoon. Several stalagmites have been dated by AMS 14C dating method since 230Th/U is not applicable due to very low U contents. Twenty (20) AMS 14C dates on Stalagmite JL20131005-10 (10-cm long) show "Bomb carbon curve", spanning the past 60 years. Lamination counting further confirms the chronology. Thirty nine (39) AMS 14C dates on Stalagmite JL20131005-12 (33-cm long) reveal 2300-year continuous growth. Stalagmite YLY20130727-12 (10-cm long) from Yilingyan Cave covers a continuous record of past 2300 years. All studied stalagmites in the caves contain low dead carbon fractions. The annual resolution δ18O and δ13C records obtained from the stalagmites allow us to compare the stalagmite δ18O records with the instrumental rainfall and temperature records, Pacific Decadal Oscillation (PDO), Southern Oscillation Index (SOI), and Sunspot variation, etc. The δ18O and δ13C records exhibit relatively good correlation throughout the time, indicating climatic control on vegetation change. Based on the high-resolution δ18O and δ13C records, we interpret that dry climatic conditions and poor vegetation coverage during periods of AD1880~1850, 1700~1600, 1460~1320, 1210~1280, 860~750, 540~420, 300~220, and AD100~0 shown by increased δ18O and δ13C. The δ18O and δ13C were strongly depleted during the Medieval Warm Period (MWP between AD900 and AD1100) and Current Warm Period (CWP, since AD1900), reflecting strongly increased East Asian Summer Monsoon. After AD1900, the δ13C decreased about 6‰, perhaps indicating human impact on surface vegetation. The δ18O records from the study area are comparable to the published WX42B δ18O record of Wanxiang Cave (Zhang et al., 2008) except for the period of AD1400~1850. Our study suggests that AMS 14C dating is an alternative method for

  14. High-resolution solid-state NMR in liquids. 2. sup 27 Al NMR study of AlF sub 3 ultrafine particles

    SciTech Connect

    Satoh, Naoki ); Kimura, Keisaku )

    1990-06-06

    High-resolution {sup 27}Al nuclear magnetic resonance spectra of AlF{sub 3} ultrafine particles (UFPs) were obtained by means of motional narrowing caused by Brownian motion of UFPs in a liquid phase. The NMR observed spectra can be resolved in five signals at 10, {minus}5, {minus}8, {minus}12, and {minus}16 ppm with respect to an Al{sup 3+}(H{sub 2}O){sub 6} standard. The UFPs were fractionated according to their sizes by using an ultrafiltration technique. From the NMR measurements of fractionated colloidal solutions, the five peaks were classified into three groups by their origins, viz. the peak at {minus}16 ppm is from larger UFPs (diameter D; 9 nm), those at {minus}5, {minus}8, and {minus}12 ppm from smaller UFPs (1 < D < 3 nm), while that at 10 ppm from free ions. Line widths of the larger and smaller UFPs were about 10 and 4 ppm (i.e., 1 and 0.4 kHz), respectively.

  15. Solid state parameters, structure elucidation, High Resolution X-Ray Diffraction (HRXRD), phase matching, thermal and impedance analysis on L-Proline trichloroacetate (L-PTCA) NLO single crystals.

    PubMed

    Kalaiselvi, P; Raj, S Alfred Cecil; Jagannathan, K; Vijayan, N; Bhagavannarayana, G; Kalainathan, S

    2014-11-11

    Nonlinear optical single crystal of L-Proline trichloroacetate (L-PTCA) was successfully grown by Slow Evaporation Solution Technique (SEST). The grown crystals were subjected to single crystal X-ray diffraction analysis to confirm the structure. From the single crystal XRD data, solid state parameters were determined for the grown crystal. The crystalline perfection has been evaluated using high resolution X-ray diffractometer. The frequencies of various functional groups were identified from FTIR spectral analysis. The percentage of transmittance was obtained from UV Visible spectral analysis. TGA-DSC measurements indicate the thermal stability of the crystal. The dielectric constant, dielectric loss and ac conductivity were measured by the impedance analyzer. The DC conductivity was calculated by the cole-cole plot method.

  16. Investigation of reaction mechanisms of drug degradation in the solid state: a kinetic study implementing ultrahigh-performance liquid chromatography and high-resolution mass spectrometry for thermally stressed thyroxine.

    PubMed

    Neu, Volker; Bielow, Chris; Schneider, Peter; Reinert, Knut; Stuppner, Hermann; Huber, Christian G

    2013-02-19

    A reaction scheme was derived for the thermal degradation of thyroxine in the solid state, using data obtained from ultrahigh-performance liquid chromatography and high-resolution mass spectrometry (UHPLC-HRMS). To study the reaction mechanism and kinetics of the thermal degradation of the pharmaceutical in the solid state, a workflow was developed by generating compound-specific, time-dependent degradation or formation curves of at least 13 different degradation products. Such curves allowed one to distinguish between first- and second-generation degradation products, as well as impurities resulting from chemical synthesis. The structures of the degradation products were derived from accurate molecular masses and multistage mass spectrometry. Deiodination and oxidative side chain degradation were found to be the major degradation reactions, resulting in the formation of deiodinated thyroxines, as well as acetic acid, benzoic acid, formaldehyde, acetamide, hydroxyacetic acid, oxoacetic acid, hydroxyacetamide, or oxoacetamide derivatives of thyroxine or deiodinated thyroxine. Upon additional structural verification of mass spectrometric data using nuclear magnetic resonance spectroscopy, this comprehensive body of data sheds light on an elaborate, radical-driven reaction scheme, explaining the presence or formation of impurities in thermally stressed thyroxine.

  17. Model-free estimation of the effective correlation time for C–H bond reorientation in amphiphilic bilayers: {sup 1}H–{sup 13}C solid-state NMR and MD simulations

    SciTech Connect

    Ferreira, Tiago Mendes; Ollila, O. H. Samuli; Pigliapochi, Roberta; Dabkowska, Aleksandra P.; Topgaard, Daniel

    2015-01-28

    Molecular dynamics (MD) simulations give atomically detailed information on structure and dynamics in amphiphilic bilayer systems on timescales up to about 1 μs. The reorientational dynamics of the C–H bonds is conventionally verified by measurements of {sup 13}C or {sup 2}H nuclear magnetic resonance (NMR) longitudinal relaxation rates R{sub 1}, which are more sensitive to motional processes with correlation times close to the inverse Larmor frequency, typically around 1-10 ns on standard NMR instrumentation, and are thus less sensitive to the 10-1000 ns timescale motion that can be observed in the MD simulations. We propose an experimental procedure for atomically resolved model-free estimation of the C–H bond effective reorientational correlation time τ{sub e}, which includes contributions from the entire range of all-atom MD timescales and that can be calculated directly from the MD trajectories. The approach is based on measurements of {sup 13}C R{sub 1} and R{sub 1ρ} relaxation rates, as well as {sup 1}H−{sup 13}C dipolar couplings, and is applicable to anisotropic liquid crystalline lipid or surfactant systems using a conventional solid-state NMR spectrometer and samples with natural isotopic composition. The procedure is demonstrated on a fully hydrated lamellar phase of 1-palmitoyl-2-oleoyl-phosphatidylcholine, yielding values of τ{sub e} from 0.1 ns for the methyl groups in the choline moiety and at the end of the acyl chains to 3 ns for the g{sub 1} methylene group of the glycerol backbone. MD simulations performed with a widely used united-atom force-field reproduce the τ{sub e}-profile of the major part of the acyl chains but underestimate the dynamics of the glycerol backbone and adjacent molecular segments. The measurement of experimental τ{sub e}-profiles can be used to study subtle effects on C–H bond reorientational motions in anisotropic liquid crystals, as well as to validate the C–H bond reorientation dynamics predicted in MD

  18. Continuous high-resolution measurements of dissolved CH4, CO2 and δ13C-CO2 in surface water during the SWERUS-C3 expedition in the East Siberian Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Geibel, Marc Christoph; Magnus Mörth, Carl; Humborg, Christoph; Semiletov, Igor

    2015-04-01

    The carbon budget in the Arctic is still unknown. Especially the fate of CH4 from subsea permafrost on the East Siberian Arctic Shelf (ESAS) is unclear. In July-September 2014 the joined SWERUS-C3 expedition on board the Swedish icebreaker ODEN was undertaken. Among its goals was to get a better insight into the fate of carbon in the Arctic, to document possible CH4 release from subsea permafrost and deep sea and to understand mechanisms and magnitudes of CH4 release to the atmosphere. During the first leg of the expedition the in situ concentration of dissolved CH4, CO2 as well as the δ13C signature of CO2 were determined. Measurements were made continuously with a Water Equilibration Gas Analyzer System (WEGAS) that was specifically developed at Stockholm University for the determination of gases dissolved in water. The aim of this study was to quantify the concentration of dissolved CO2 and CH4 in the surface water of the East Siberian Arctic Ocean (ESAO) as well as the contribution of terrestrial organic matter respiration to the dissolved inorganic carbon (DIC). Combined with continuous high-precision atmospheric measurements that were performed during the SWERUS-C3 expedition, the WEGAS dataset will allow to calculate accurate high-resolution CH4 fluxes and thus give a better insight into the current outgassing of CH4 to the atmosphere. Together with measurements of δ13C of inorganic carbon that was sampled during the expedition, the isotopic composition of the dissolved organic carbon pool will allow to quantify the of terrestrial carbon contribution to total respiration in the ESAO.

  19. Solid state 13C-NMR, infrared, X-ray powder diffraction and differential thermal studies of the homologous series of some mono-valent metal (Li, Na, K, Ag) n-alkanoates: A comparative study

    NASA Astrophysics Data System (ADS)

    Nelson, Peter N.; Ellis, Henry A.; White, Nicole A. S.

    2015-06-01

    A comparative study of the molecular packing, lattice structures and phase behaviors of the homologous series of some mono-valent metal carboxylates (Li, Na, K and Ag) is carried out via solid state FT-infrared and 13C-NMR spectroscopes, X-rays powder diffraction, density measurements, differential scanning calorimetry, polarizing light microscopy and variable temperature infrared spectroscopy. It is proposed that, for lithium, sodium and potassium carboxylates, metal-carboxyl coordination is via asymmetric chelating bidentate bonding with extensive intermolecular interactions to form tetrahedral metal centers, irrespective of chain length. However, for silver n-alkanoates, carboxyl moieties are bound to silver ions via syn-syn type bridging bidentate coordination to form dimeric units held together by extensive head group inter-molecular interactions. Furthermore, the fully extended hydrocarbon chains which are crystallized in the all-trans conformation are tilted at ca. 30°, 27°, 15° and 31° with respect to a normal to the metal plane, for lithium, sodium, silver and potassium carboxylates, respectively. All compounds are packed as lamellar bilayer structures, however, lithium compounds are crystallized in a triclinic crystal system whilst silver, sodium and potassium n-alkanoates are all monoclinic with possible P1 bravais lattice. Odd-even alternation observed in various physical features is associated with different inter-planar spacing between closely packed layers in the bilayer which are not in the same plane; a phenomenon controlled by lattice packing symmetry requirements. All compounds, except silver carboxylates, show partially reversibly first order pre-melting transitions; the number of which increases with increasing chain length. These transitions are associated, for the most part, with lamellar collapse followed by increased gauche-trans isomerism in the methylene group assembly, irrespective of chain length. It is proposed that the absence of

  20. 1H, 15N, and 13C backbone chemical shift assignments, secondary structure, and magnesium-binding characteristics of the Bacillus subtilis response regulator, Spo0F, determined by heteronuclear high-resolution NMR.

    PubMed Central

    Feher, V. A.; Zapf, J. W.; Hoch, J. A.; Dahlquist, F. W.; Whiteley, J. M.; Cavanagh, J.

    1995-01-01

    Spo0F, sporulation stage 0 F protein, a 124-residue protein responsible, in part, for regulating the transition of Bacillus subtilis from a vegetative state to a dormant endospore, has been studied by high-resolution NMR. The 1H, 15N, and 13C chemical shift assignments for the backbone residues have been determined from analyses of 3D spectra, 15N TOCSY-HSQC, 15N NOESY-HSQC, HNCA, and HN(CO)CA. Assignments for many sidechain proton resonances are also reported. The secondary structure, inferred from short- and medium-range NOEs, 3JHN alpha coupling constants, and hydrogen exchange patterns, define a topology consistent with a doubly wound (alpha/beta)5 fold. Interestingly, comparison of the secondary structure of Spo0F to the structure of the Escherichia coli response regulator, chemotaxis Y protein (CheY) (Volz K, Matsumura P, 1991, J Biol Chem 266:15511-15519; Bruix M et al., 1993, Eur J Biochem 215:573-585), show differences in the relative length of secondary structure elements that map onto a single face of the tertiary structure of CheY. This surface may define a region of binding specificity for response regulators. Magnesium titration of Spo0F, followed by amide chemical shift changes, gives an equilibrium dissociation constant of 20 +/- 5 mM. Amide resonances most perturbed by magnesium binding are near the putative site of phosphorylation, Asp 54. PMID:8528078

  1. Ground-fire effects on the composition of dissolved and total organic matter in forest floor and soil solutions from Scots pine forests in Germany: new insights from solid state 13C NMR analysis

    NASA Astrophysics Data System (ADS)

    Näthe, Kerstin; Michalzik, Beate; Levia, Delphis; Steffens, Markus

    2016-04-01

    Fires represent an ecosystem disturbance and are recognized to seriously pertubate the nutrient budgets of forested ecosystems. While the effects of fires on chemical, biological, and physical soil properties have been intensively studied, especially in Mediterranean areas and North America, few investigations examined the effects of fire-induced alterations in the water-bound fluxes and the chemical composition of dissolved and particulate organic carbon and nitrogen (DOC, POC, DN, PN). The exclusion of the particulate organic matter fraction (0.45 μm < POM < 500 μm) potentially results in misleading inferences and budgeting gaps when studying the effects of fires on nutrient and energy fluxes. To our best knowledge, this is the first known study to present fire-induced changes on the composition of dissolved and total organic matter (DOM, TOM) in forest floor (FF) and soil solutions (A, B horizon) from Scots pine forests in Germany. In relation to control sites, we test the effects of low-severity fires on: (1) the composition of DOM and TOM in forest floor and soil solutions; and (2) the translocated amount of particulate in relation to DOC and DN into the subsoil. The project aims to uncover the mechanisms of water-bound organic matter transport along an ecosystem profile and its compositional changes following a fire disturbance. Forest floor and soil solutions were fortnightly sampled from March to December 2014 on fire-manipulated and control plots in a Scots pine forest in Central Germany. Shortly after the experimental duff fire in April 2014 pooled solutions samples were taken for solid-state 13C NMR spectroscopy to characterize DOM (filtered solution < 0.8μm pore size) and TOM in unfiltered solutions. Independent from fire manipulation, the composition of TOM was generally less aromatic (aromaticity index [%] according to Hatcher et al., 1981) with values between 18 (FF) - 25% (B horizon) than the DOM fraction with 23 (FF) - 27% (B horizon). For DOM

  2. Effect of iron content on the structure and disorder of iron-bearing sodium silicate glasses: A high-resolution 29Si and 17O solid-state NMR study

    NASA Astrophysics Data System (ADS)

    Kim, Hyo-Im; Sur, Jung Chul; Lee, Sung Keun

    2016-01-01

    Despite its geochemical importance and implications for the properties of natural magmatic melts, understanding the detailed structure of iron-bearing silicate glasses remains among the outstanding problems in geochemistry. This is mainly because solid-state NMR techniques, one of the most versatile experimental methods to probe the structure of oxide glasses, cannot be fully utilized for exploring the structural details of iron-bearing glasses as the unpaired electrons in Fe induce strong local magnetic fields that mask the original spectroscopic features (i.e., paramagnetic effect). Here, we report high-resolution 29Si and 17O solid-state NMR spectra of iron-bearing sodium silicate glasses (Na2O-Fe2O3-SiO2, Fe3+/ΣFe = 0.89 ± 0.04, thus containing both ferric and ferrous iron) with varying XFe2O3 [=Fe2O3/(Na2O + Fe2O3)], containing up to 22.9 wt% Fe2O3. This compositional series involves Fe-Na substitution at constant SiO2 contents of 66.7 mol% in the glasses. For both nuclides, the NMR spectra exhibit a decrease in the signal intensities and an increase in the peak widths with increasing iron concentration partly because of the paramagnetic effect. Despite the intrinsic difficulties that result from the pronounced paramagnetic effect, the 29Si and 17O NMR results yield structural details regarding the effect of iron content on Q speciation, spatial distribution of iron, and the extent of polymerization in the iron-bearing silicate glasses. The 29Si NMR spectra show an apparent increase in highly polymerized Q species with increasing XFe2O3 , suggesting an increase in the degree of melt polymerization. The 17O 3QMAS NMR spectra exhibit well-resolved non-bridging oxygen (NBO, Na-O-Si) and bridging oxygen (BO, Si-O-Si) peaks with varying iron concentration. By replacing Na2O with Fe2O3 (and thus with increasing iron content), the fraction of Na-O-Si decreases. Quantitative consideration of this effect confirms that the degree of polymerization is likely to

  3. Ultrahigh-performance liquid chromatography-ultraviolet absorbance detection-high-resolution-mass spectrometry combined with automated data processing for studying the kinetics of oxidative thermal degradation of thyroxine in the solid state.

    PubMed

    Neu, Volker; Bielow, Chris; Reinert, Knut; Huber, Christian G

    2014-12-01

    Levothyroxine as active pharmaceutical ingredient of formulations used for the treatment of hypothyroidism is distributed worldwide and taken by millions of people. An important issue in terms of compound stability is its capability to react with ambient oxygen, especially in case of long term compound storage at elevated temperature. In this study we demonstrate that ultrahigh-performance liquid chromatography coupled to UV spectrometry and high-resolution mass spectrometry (UHPLC-UV-HRMS) represent very useful approaches to investigate the influence of ambient oxygen on the degradation kinetics of levothyroxine in the solid state at enhanced degradation conditions. Moreover, the impurity pattern of oxidative degradation of levothyroxine is elucidated and classified with respect to degradation kinetics at different oxygen levels. Kinetic analysis of thyroxine bulk material at 100 °C reveals bi-phasic degradation kinetics with a distinct change in degradation phases dependent on the availability of oxygen. The results clearly show that contact of the bulk material to ambient oxygen is a key factor for fast compound degradation. Furthermore, the combination of time-resolved HRMS data and automated data processing is shown to allow insights into the kinetics and mechanism of impurity formation on individual compound basis. By comparing degradation profiles, four main classes of profiles linked to reaction pathways of thyroxine degradation were identifiable. Finally, we show the capability of automated data processing for the matching of different stressing conditions, in order to extract information about mechanistic similarities. As a result, degradation kinetics is influenced by factors like availability of oxygen, stressing time, or stressing temperature, while the degradation mechanisms appear to be conserved.

  4. Solid-State NMR Study of Paramagnetic Bis(alaninato-κ(2)N,O)copper(II) and Bis(1-amino(cyclo)alkane-1-carboxylato-κ(2)N,O)copper(II) Complexes: Reflection of Stereoisomerism and Molecular Mobility in (13)C and (2)H Fast Magic Angle Spinning Spectra.

    PubMed

    Szalontai, Gábor; Csonka, Róbert; Speier, Gábor; Kaizer, József; Sabolović, Jasmina

    2015-05-18

    Solid-state stereochemistry and mobility of paramagnetic copper(II) complexes formed by aliphatic amino acids (l-alanine, d,l-alanine, 1-amino-2-methyl-alanine) and 1-amino(cyclo)alkane-1-carboxylic acids (alkane = propane, butane, pentane, hexane) as bidentate ligands has been studied by (13)C and (2)H solid-state fast magic angle spinning (MAS) NMR spectroscopy. We examined the prospective method to characterize solid-state paramagnetic compounds in a routine way. Both (13)C and (2)H MAS spectra can distinguish d,l and l,l diastereomers of natural and polydeuterated bis([Dn]alaninato)copper(II) (n = 0, 2, 8) complexes with axial and/or equatorial methyl positions (conformations) primarily due to different Fermi-contact (FC) contributions. The three-bond hyperfine couplings clearly show Karplus-like dependence on the torsional angles which turned out to be a useful assignment aid. Density functional theory calculations of the FC term and crystal structures were also used to aid the final assignments. The correlations obtained for bis(alaninato-κ(2)N,O)copper(II) complexes were successfully used to characterize other complexes. The usefulness of the (2)H MAS spectra of the deuterated complexes was underlined. Even the spectra of the easily exchangeable amine protons contained essential stereochemical information. In the case of a dimer structure of bis(1-aminohexane-1-carboxylato-κ(2)N,O)copper(II) both the (13)C and (2)H resolutions were good enough to confirm the presence of the cis and trans forms in the asymmetric unit. With regard to the internal solid-state motions in the crystal lattice, the obtained quadrupolar tensor parameters were similar for the d,l- and l,l-alaninato isomers and also for the cis-trans forms suggesting similar crystal packing effects, static amine deuterons involved in hydrogen bonding, and fast rotating methyl groups.

  5. High-resolution solid-state NMR study of the effect of composition on network connectivity and structural disorder in multi-component glasses in the diopside and jadeite join: Implications for structure of andesitic melts

    NASA Astrophysics Data System (ADS)

    Park, Sun Young; Lee, Sung Keun

    2014-12-01

    The structural evolution of andesitic melts with varying compositions remains one of the unsolved questions in high-temperature geochemistry and petrology. In this article, we report the structural details of model andesitic glasses [CaO-MgO-Na2O-Al2O3-SiO2 (CMNAS)] in the diopside (CaMgSi2O6) and jadeite (NaAlSi2O6) join using high-resolution, multi-nuclear, solid-state nuclear magnetic resonance (NMR). The 27Al NMR spectra of CMNAS glasses confirm that [4]Al is dominant. While a minor fraction of [5]Al is observed, its presence is only prevalent in the glasses with higher Ca-Mg content. Topological disorder in the glass network also tends to increase with Ca-Mg content as evidenced by the increase in the quadrupolar coupling constant (Cq) of [4]Al for glasses with increasing diopside contents (XDiopside). Despite the complex nature of the glasses studied here (with five oxide components), the 17O 3QMAS NMR spectra resolve diverse bridging oxygens (BOs) and non-bridging oxygens (NBOs), from which the degree of Al avoidance among framework cations (Si and Al) and preferential proximity among non-network cations (Ca2+, Mg2+, and Na+) and each oxygen site can be estimated: presence of Al-O-Al in jadeite glass implies a violation of the Al-avoidance rule in the glasses and the decrease in the fraction of NBOs with increasing XDiopside is consistent with a decrease in their viscosity. Analysis of the peak position of {Ca, Mg}-mixed NBOs, along with the absence of Na-NBO peak, and the peak shape of Si-O-Al reveals preferential partitioning of Ca2+ and Mg2 into NBOs and the proximity of Na+ to BOs. The fraction of highly coordinated Al has been linked to thermodynamic and transport properties of the melts. Considering all the experimental Al coordination environments available in the literature, together with the current experimental studies, we attempt to establish the relationship between the fractions of highly coordinated Al and composition, particularly average

  6. A new approach for reconstruction of the Holocene climate in the Mongolian Altai: The high-resolution δ13C records of TOC and pollen complexes in Hoton-Nur Lake sediments

    NASA Astrophysics Data System (ADS)

    Rudaya, Natalia; Li, Hong-Chun

    2013-06-01

    δ13C of total organic carbon (TOC) and pollen grain, TOC, C/N ratio, and δ15N of total organic nitrogen (TON) in a 2.57-m long core from Hoton-Nur Lake in Mongolian Altai have been measured for reconstruction of the Holocene climates. The δ13C values of TOC and pollen carbon have similar average values but different ranges. Pollen δ13C has negative correlation with %AP (arboreal taxa pollen) and positive correlation with %NAP (herbaceous pollen and spores) that are connected with conditions of humidity in the area. Taiga-biome has lighter δ13C than steppe-biome. Hence, pollen δ13C composition is more sensitive to changes of humidity in the analogous spectra than palynotaxonomical structure and δ13C of TOC. Based on our results, the Holocene climates in Mongolian Altai are: (1) dry conditions prior to 11.5 kyr BP; (2) wet conditions between 11.5 and 6.0 kyr BP; (3) a relatively dry/cool episode during 6-4 kyr BP; (4) stable cool and semiarid conditions with moderately effective moisture during the past 4000 years. Two abrupt climatic changes occurred at ˜7.45 kyr BP and ˜11.5 kyr BP might be related to glacial activities. The Holocene climatic trend in Mongolian Altai which is controlled by the Westerlies is similar to the trend of monsoonal climate shown by the Chinese speleothem records as well as the lake/sand dune evidence in the deserts of NW China. The contact of the two climatic systems and shift of the monsoonal boundary during the past need to be further studied.

  7. Characterization of organic matter in pristine and contaminated coastal marine sediments using solid-state 13C NMR, pyrolytic and thermochemolytic methods: a case study in the San Diego harbor area.

    PubMed

    Deshmukh, A P; Chefetz, B; Hatcher, P G

    2001-11-01

    Chemical composition of coastal marine sedimentary organic matter (SDOM) is a function of natural and anthropogenic inputs to the system. In this study a combination of analytical techniques: 13C nuclear magnetic resonance (NMR), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and tetramethylammonium hydroxide thermochemolysis-gas chromatography/mass spectrometry (TMAH thermochemolysis-GC/MS) were used to study the contribution of hydrophobic organic contaminants and terrestrial OM to the SDOM. Sediments were collected from two sites in the San Diego Bay: Paleta Creek, which is contaminated, and Coronado Cayes, which is relatively pristine. Concentrations of polycyclic aromatic hydrocarbons (PAHs) at both sites, as determined by ultrasonically assisted lipid extraction are found to be higher in the surface layer, to generally decrease with depth, and to be present at about two orders of magnitude higher concentration at the contaminated site as compared to the pristine site. The sediment samples were partially deashed with HF/HCI treatment before further analysis. 13C-NMR spectra of the Paleta Creek samples show a higher aromatic carbon content and a distinct phenolic carbon peak. This suggests a large input from terrestrial carbon (lignin). Data from both Py-GC/MS and TMAH thermochemolysis-GC/MS support this and indicate the presence of lignin-derived residues, primarily of the guaiacyl type at the contaminated site. In contrast, SDOM at the Coronado Cayes site exhibits less terrestrial input. In general, the SDOM resembles soil OM rather than typical marine SDOM. Chemical analyses of the lipid-extracted, partially deashed sediments, does not reveal the presence of any PAHs.

  8. Characterization of polysulfone and polysulfone/vanillin microcapsules by 1H NMR spectroscopy, solid-state 13C CP/MAS-NMR spectroscopy, and N2 adsorption-desorption analyses.

    PubMed

    Peña, Brisa; de Ménorval, Louis-Charles; Garcia-Valls, Ricard; Gumí, Tània

    2011-11-01

    Textile detergent and softener industries have incorporated perfume microencapsulation technology to improve their products. Perfume encapsulation allows perfume protection until use and provides a long-lasting fragrance release. But, certain industrial microcapsules show low encapsulation capacity and low material stability. Polysulfone capsules have been already proposed to solve these drawbacks. Among them, PSf/Vanillin capsules were considered as a desirable system. They present both good material stability and high encapsulation capacity. However, several factors such as the final location of the perfume in the polymeric matrix, the aggregation state that it has in the capsule and its interaction with the capsule components have not been studied yet. These factors can provide vast information about the capsule performance and its improvement. With the aim to characterize these parameters, the physical and chemical properties of PSf/Vanillin capsules have been investigated by nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and N(2) adsorption-desorption measurements. AFM micrograph and N(2) isotherms confirm that the presence of vanillin modify the physical structure of PSf/Vanillin microcapsules as it is trapped in the capsule porosity. NMR results show that vanillin is present in solid state in PSf/Vanillin microcapsules.

  9. Solid state optical microscope

    DOEpatents

    Young, Ian T.

    1983-01-01

    A solid state optical microscope wherein wide-field and high-resolution images of an object are produced at a rapid rate by utilizing conventional optics with a charge-coupled photodiode array. A galvanometer scanning mirror, for scanning in one of two orthogonal directions is provided, while the charge-coupled photodiode array scans in the other orthogonal direction. Illumination light from the object is incident upon the photodiodes, creating packets of electrons (signals) which are representative of the illuminated object. The signals are then processed, stored in a memory, and finally displayed as a video signal.

  10. Solid state optical microscope

    DOEpatents

    Young, I.T.

    1983-08-09

    A solid state optical microscope wherein wide-field and high-resolution images of an object are produced at a rapid rate by utilizing conventional optics with a charge-coupled photodiode array. A galvanometer scanning mirror, for scanning in one of two orthogonal directions is provided, while the charge-coupled photodiode array scans in the other orthogonal direction. Illumination light from the object is incident upon the photodiodes, creating packets of electrons (signals) which are representative of the illuminated object. The signals are then processed, stored in a memory, and finally displayed as a video signal. 2 figs.

  11. Participation of the surface structure of Pharaonis phoborhodopsin, ppR and its A149S and A149V mutants, consisting of the C-terminal alpha-helix and E-F loop, in the complex-formation with the cognate transducer pHtrII, as revealed by site-directed 13C solid-state NMR.

    PubMed

    Kawamura, Izuru; Ikeda, Yoichi; Sudo, Yuki; Iwamoto, Masayuki; Shimono, Kazumi; Yamaguchi, Satoru; Tuzi, Satoru; Saitô, Hazime; Kamo, Naoki; Naito, Akira

    2007-01-01

    We have recorded 13C solid state NMR spectra of [3-13C]Ala-labeled pharaonis phoborhodopsin (ppR) and its mutants, A149S and A149V, complexed with the cognate transducer pharaonis halobacterial transducer II protein (pHtrII) (1-159), to gain insight into a possible role of their cytoplasmic surface structure including the C-terminal alpha-helix and E-F loop for stabilization of the 2:2 complex, by both cross-polarization magic angle spinning (CP-MAS) and dipolar decoupled (DD)-MAS NMR techniques. We found that 13C CP-MAS NMR spectra of [3-13C]Ala-ppR, A149S and A149V complexed with the transducer pHtrII are very similar, reflecting their conformation and dynamics changes caused by mutual interactions through the transmembrane alpha-helical surfaces. In contrast, their DD-MAS NMR spectral features are quite different between [3-13C]Ala-A149S and A149V in the complexes with pHtrII: 13C DD-MAS NMR spectrum of [3-13C]Ala-A149S complex is rather similar to that of the uncomplexed form, while the corresponding spectral feature of A149V complex is similar to that of ppR complex in the C-terminal tip region. This is because more flexible surface structure detected by the DD-MAS NMR spectra are more directly influenced by the dynamics changes than the CP-MAS NMR. It turned out, therefore, that an altered surface structure of A149S resulted in destabilized complex as viewed from the 13C NMR spectrum of the surface areas, probably because of modified conformation at the corner of the helix E in addition to the change of hydropathy. It is, therefore, concluded that the surface structure of ppR including the C-terminal alpha-helix and the E-F loops is directly involved in the stabilization of the complex through conformational stability of the helix E.

  12. 13C and 15N CP/MAS, 1H-15N SCT CP/MAS and FTIR spectroscopy as tools for qualitative detection of the presence of zwitterionic and non-ionic forms of ansa-macrolide 3-formylrifamycin SV and its derivatives in solid state.

    PubMed

    Przybylski, Piotr; Pyta, Krystian; Klich, Katarzyna; Schilf, Wojciech; Kamieński, Bohdan

    2014-01-01

    (13)C, (15)N CP/MAS, including (1)H-(13)C and (1)H-(15)N short contact time CP/MAS experiments, and FTIR methods were applied for detailed structural characterization of ansa-macrolides as 3-formylrifamycin SV (1) and its derivatives (2-6) in crystal and in powder forms. Although HPLC chromatograms for 2/CH3 OH and 2/CH3 CCl3 were the same for rifampicin crystals dissolved in respective solvents, the UV-vis data recorded for them were different in 300-375 nm region. Detailed solid state (13)C and (15)N CP/MAS NMR and FTIR studies revealed that rifampicin (2), in contrast to 3-formylrifamycin SV (1) and its amino derivatives (3-6), can occur in pure non-ionic or zwitterionic forms in crystal and in pure these forms or a mixture of them in a powder. Multinuclear CP/MAS and FTIR studies demonstrated also that 3-6 derivatives were present exclusively in pure zwitterionic forms, both in powder and in crystal. On the basis of the solid state NMR and FTIR studies, two conformers of 3-formylrifamycin SV were detected in powder form due to the different orientations of carbonyl group of amide moiety. The PM6 molecular modeling at the semi-empirical level of theory, allowed visualization the most energetically favorable non-ionic and zwitterionic forms of 1-6 antibiotics, strongly stabilized via intramolecular H-bonds. FTIR studies indicated that the originally adopted forms of these type antibiotics in crystal or in powder are stable in standard laboratory conditions in time. The results presented point to the fact that because of a possible presence of two forms of rifampicin (compound 2), quantification of the content of this antibiotic in relevant pharmaceuticals needs caution. PMID:24347399

  13. 13C and 15N CP/MAS, 1H-15N SCT CP/MAS and FTIR spectroscopy as tools for qualitative detection of the presence of zwitterionic and non-ionic forms of ansa-macrolide 3-formylrifamycin SV and its derivatives in solid state.

    PubMed

    Przybylski, Piotr; Pyta, Krystian; Klich, Katarzyna; Schilf, Wojciech; Kamieński, Bohdan

    2014-01-01

    (13)C, (15)N CP/MAS, including (1)H-(13)C and (1)H-(15)N short contact time CP/MAS experiments, and FTIR methods were applied for detailed structural characterization of ansa-macrolides as 3-formylrifamycin SV (1) and its derivatives (2-6) in crystal and in powder forms. Although HPLC chromatograms for 2/CH3 OH and 2/CH3 CCl3 were the same for rifampicin crystals dissolved in respective solvents, the UV-vis data recorded for them were different in 300-375 nm region. Detailed solid state (13)C and (15)N CP/MAS NMR and FTIR studies revealed that rifampicin (2), in contrast to 3-formylrifamycin SV (1) and its amino derivatives (3-6), can occur in pure non-ionic or zwitterionic forms in crystal and in pure these forms or a mixture of them in a powder. Multinuclear CP/MAS and FTIR studies demonstrated also that 3-6 derivatives were present exclusively in pure zwitterionic forms, both in powder and in crystal. On the basis of the solid state NMR and FTIR studies, two conformers of 3-formylrifamycin SV were detected in powder form due to the different orientations of carbonyl group of amide moiety. The PM6 molecular modeling at the semi-empirical level of theory, allowed visualization the most energetically favorable non-ionic and zwitterionic forms of 1-6 antibiotics, strongly stabilized via intramolecular H-bonds. FTIR studies indicated that the originally adopted forms of these type antibiotics in crystal or in powder are stable in standard laboratory conditions in time. The results presented point to the fact that because of a possible presence of two forms of rifampicin (compound 2), quantification of the content of this antibiotic in relevant pharmaceuticals needs caution.

  14. Analysis of commercial proanthocyanidins. Part 4: solid state (13)C NMR as a tool for in situ analysis of proanthocyanidin tannins, in heartwood and bark of quebracho and acacia, and related species.

    PubMed

    Reid, David G; Bonnet, Susan L; Kemp, Gabre; van der Westhuizen, Jan H

    2013-10-01

    (13)C NMR is an effective method of characterizing proanthocyanidin (PAC) tannins in quebracho (Schinopsis lorentzii) heartwood and black wattle (Acacia mearnsii) bark, before and after commercial extraction. The B-rings of the constituent flavan-3-ols, catechols (quebracho) or pyrogallols (wattle), are recognized in unprocessed source materials by "marker" signals at ca. 118 or 105ppm, respectively. NMR allows the minimum extraction efficiency to be calculated; ca. 30%, and ca. 80%, for quebracho heartwood and black wattle bark, respectively. NMR can also identify PAC tannin (predominantly robinetinidin), and compare tannin content, in bark from other acacia species; tannin content decreases in the order A. mearnsii, Acacia pycnantha (87% of A. mearnsii), Acacia dealbata and Acacia decurrens (each 74%) and Acacia karroo (30%). Heartwood from an underexploited PAC tannin source, Searsia lancea, taxonomically close to quebracho, shows abundant profisetinidin and catechin PACs. NMR offers the advantage of being applicable to source materials in their native state, and has potential applications in optimizing extraction processes, identification of tannin sources, and characterization of tannin content in cultivar yield improvement programmes. PMID:23838626

  15. Analysis of commercial proanthocyanidins. Part 4: solid state (13)C NMR as a tool for in situ analysis of proanthocyanidin tannins, in heartwood and bark of quebracho and acacia, and related species.

    PubMed

    Reid, David G; Bonnet, Susan L; Kemp, Gabre; van der Westhuizen, Jan H

    2013-10-01

    (13)C NMR is an effective method of characterizing proanthocyanidin (PAC) tannins in quebracho (Schinopsis lorentzii) heartwood and black wattle (Acacia mearnsii) bark, before and after commercial extraction. The B-rings of the constituent flavan-3-ols, catechols (quebracho) or pyrogallols (wattle), are recognized in unprocessed source materials by "marker" signals at ca. 118 or 105ppm, respectively. NMR allows the minimum extraction efficiency to be calculated; ca. 30%, and ca. 80%, for quebracho heartwood and black wattle bark, respectively. NMR can also identify PAC tannin (predominantly robinetinidin), and compare tannin content, in bark from other acacia species; tannin content decreases in the order A. mearnsii, Acacia pycnantha (87% of A. mearnsii), Acacia dealbata and Acacia decurrens (each 74%) and Acacia karroo (30%). Heartwood from an underexploited PAC tannin source, Searsia lancea, taxonomically close to quebracho, shows abundant profisetinidin and catechin PACs. NMR offers the advantage of being applicable to source materials in their native state, and has potential applications in optimizing extraction processes, identification of tannin sources, and characterization of tannin content in cultivar yield improvement programmes.

  16. Multiple locations of peptides in the hydrocarbon core of gel-phase membranes revealed by peptide (13)C to lipid (2)H rotational-echo double-resonance solid-state nuclear magnetic resonance.

    PubMed

    Xie, Li; Jia, Lihui; Liang, Shuang; Weliky, David P

    2015-01-27

    Membrane locations of peptides and proteins are often critical to their functions. Solid-state rotational-echo double-resonance (REDOR) nuclear magnetic resonance is applied to probe the locations of two peptides via peptide (13)CO to lipid (2)H distance measurements. The peptides are KALP, an α-helical membrane-spanning peptide, and HFP, the β-sheet N-terminal fusion peptide of the HIV gp41 fusion protein that plays an important role in HIV-host cell membrane fusion. Both peptides are shown to have at least two distinct locations within the hydrocarbon core of gel-phase membranes. The multiple locations are attributed to snorkeling of lysine side chains for KALP and to the distribution of antiparallel β-sheet registries for HFP. The relative population of each location is also quantitated. To the best of our knowledge, this is the first clear experimental support of multiple peptide locations within the membrane hydrocarbon core. These data are for gel-phase membranes, but the approach should work for liquid-ordered membranes containing cholesterol and may be applicable to liquid-disordered membranes with appropriate additional analysis to take into account protein and lipid motion. This paper also describes the methodological development of (13)CO-(2)H REDOR using the lyophilized I4 peptide that is α-helical and (13)CO-labeled at A9 and (2)Hα-labeled at A8. The I4 spins are well-approximated as an ensemble of isolated (13)CO-(2)H spin pairs each separated by 5.0 Å with a 37 Hz dipolar coupling. A pulse sequence with rectangular 100 kHz (2)H π pulses results in rapid and extensive buildup of REDOR (ΔS/S0) with a dephasing time (τ). The buildup is well-fit by a simple exponential function with a rate of 24 Hz and an extent close to 1. These parameter values reflect nonradiative transitions between the (2)H spin states during the dephasing period. Each spin pair spends approximately two-thirds of its time in the (13)CO-(2)H (m = ±1) states and

  17. Investigating albendazole desmotropes by solid-state NMR spectroscopy.

    PubMed

    Chattah, Ana K; Zhang, Rongchun; Mroue, Kamal H; Pfund, Laura Y; Longhi, Marcela R; Ramamoorthy, Ayyalusamy; Garnero, Claudia

    2015-03-01

    Characterization of the molecular structure and physicochemical solid-state properties of the solid forms of pharmaceutical compounds is a key requirement for successful commercialization as potential active ingredients in drug products. These properties can ultimately have a critical effect on the solubility and bioavailability of the final drug product. Here, the desmotropy of Albendazole forms I and II was investigated at the atomic level. Ultrafast magic angle spinning (MAS) solid-state nuclear magnetic resonance (NMR) spectroscopy, together with powder X-ray diffraction, thermal analysis, and Fourier transform infrared spectroscopy, were performed on polycrystalline samples of the two solids in order to fully characterize and distinguish the two forms. High-resolution one-dimensional (1)H, (13)C, and (15)N together with two-dimensional (1)H/(1)H single quantum-single quantum, (1)H/(1)H single quantum-double quantum, and (1)H/(13)C chemical shift correlation solid-state NMR experiments under MAS conditions were extensively used to decipher the intramolecular and intermolecular hydrogen bonding interactions present in both solid forms. These experiments enabled the unequivocal identification of the tautomers of each desmotrope. Our results also revealed that both solid forms may be described as dimeric structures, with different intermolecular hydrogen bonds connecting the tautomers in each dimer. PMID:25584993

  18. Degradation of mangrove tissues by arboreal termites (Nasutitermes acajutlae) and their role in the mangrove C cycle (Puerto Rico): Chemical characterization and organic matter provenance using bulk δ13C, C/N, alkaline CuO oxidation-GC/MS, and solid-state 13C NMR

    NASA Astrophysics Data System (ADS)

    Vane, Christopher H.; Kim, Alexander W.; Moss-Hayes, Vicky; Snape, Colin E.; Diaz, Miguel Castro; Khan, Nicole S.; Engelhart, Simon E.; Horton, Benjamin P.

    2013-08-01

    Arboreal termites are wood decaying organisms that play an important role in the first stages of C cycling in mangrove systems. The chemical composition of Rhizophora mangle, Avicennia germinans, and Laguncularia racemosa leaf, stem, and pneumatophore tissues as well as associated sediments was compared to that of nests of the termite Nasutitermes acajutlae. Nests gave δ13C values of -26.1 to -27.2‰ (±0.1) and C/N of 43.3 (±2.0) to 98.6 (±16.2) which were similar to all stem and pneumatophores but distinct from mangrove leaves or sediments. Organic matter processed by termites yielded lignin phenol concentrations (Λ, lambda) that were 2-4 times higher than stem or pneumatophores and 10-20 times higher than that of leaves or sediments, suggesting that the nests were more resistant to biodegradation than the mangrove vegetation source. 13C NMR revealed that polysaccharide content of mangrove tissues (50-69% C) was higher than that of the nests (46-51% C). Conversely, lignin accounted for 16.2-19.6% C of nest material, a threefold increase relative to living mangrove tissues; a similar increase in aromatic methoxyl content was also observed in the nests. Lipids (aliphatic and paraffinic moieties) were also important but rather variable chemical components of all three mangrove species, representing between 13.5 and 28.3% of the C content. Termite nests contained 3.14 Mg C ha-1 which represents approximately 2% of above ground C storage in mangroves, a value that is likely to increase upon burial due to their refractory chemical composition.

  19. Molecular indicators for palaeoenvironmental change in a Messinian evaporitic sequence (Vena del Gesso, Italy). II: High-resolution variations in abundances and 13C contents of free and sulphur-bound carbon skeletons in a single marl bed.

    PubMed

    Kenig, F; Damsté, J S; Frewin, N L; Hayes, J M; De Leeuw, J W

    1995-06-01

    The extractable organic matter of 10 immature samples from a marl bed of one evaporitic cycle of the Vena del Gesso sediments (Gessoso-solfifera Fm., Messinian, Italy) was analyzed quantitatively for free hydrocarbons and organic sulphur compounds. Nickel boride was used as a desulphurizing agent to recover sulphur-bound lipids from the polar and asphaltene fractions. Carbon isotopic compositions (delta vs PDB) of free hydrocarbons and of S-bound hydrocarbons were also measured. Relationships between these carbon skeletons, precursor biolipids, and the organisms producing them could then be examined. Concentrations of S-bound lipids and free hydrocarbons and their delta values were plotted vs depth in the marl bed and the profiles were interpreted in terms of variations in source organisms, 13 C contents of the carbon source, and environmentally induced changes in isotopic fractionation. The overall range of delta values measured was 24.7%, from -11.6% for a component derived from green sulphur bacteria (Chlorobiaceae) to -36.3% for a lipid derived from purple sulphur bacteria (Chromatiaceae). Deconvolution of mixtures of components deriving from multiple sources (green and purple sulphur bacteria, coccolithophorids, microalgae and higher plants) was sometimes possible because both quantitative and isotopic data were available and because either the free or S-bound pool sometimes appeared to contain material from a single source. Several free n-alkanes and S-bound lipids appeared to be specific products of upper-water-column primary producers (i.e. algae and cyanobacteria). Others derived from anaerobic photoautotrophs and from heterotrophic protozoa (ciliates), which apparently fed partly on Chlorobiaceae. Four groups of n-alkanes produced by algae or cyanobacteria were also recognized based on systematic variations of abundance and isotopic composition with depth. For hydrocarbons probably derived from microalgae, isotopic variations are well correlated with

  20. Molecular indicators for palaeoenvironmental change in a Messinian evaporitic sequence (Vena del Gesso, Italy). II: High-resolution variations in abundances and 13C contents of free and sulphur-bound carbon skeletons in a single marl bed

    NASA Technical Reports Server (NTRS)

    Kenig, F.; Damste, J. S.; Frewin, N. L.; Hayes, J. M.; De Leeuw, J. W.

    1995-01-01

    The extractable organic matter of 10 immature samples from a marl bed of one evaporitic cycle of the Vena del Gesso sediments (Gessoso-solfifera Fm., Messinian, Italy) was analyzed quantitatively for free hydrocarbons and organic sulphur compounds. Nickel boride was used as a desulphurizing agent to recover sulphur-bound lipids from the polar and asphaltene fractions. Carbon isotopic compositions (delta vs PDB) of free hydrocarbons and of S-bound hydrocarbons were also measured. Relationships between these carbon skeletons, precursor biolipids, and the organisms producing them could then be examined. Concentrations of S-bound lipids and free hydrocarbons and their delta values were plotted vs depth in the marl bed and the profiles were interpreted in terms of variations in source organisms, 13 C contents of the carbon source, and environmentally induced changes in isotopic fractionation. The overall range of delta values measured was 24.7%, from -11.6% for a component derived from green sulphur bacteria (Chlorobiaceae) to -36.3% for a lipid derived from purple sulphur bacteria (Chromatiaceae). Deconvolution of mixtures of components deriving from multiple sources (green and purple sulphur bacteria, coccolithophorids, microalgae and higher plants) was sometimes possible because both quantitative and isotopic data were available and because either the free or S-bound pool sometimes appeared to contain material from a single source. Several free n-alkanes and S-bound lipids appeared to be specific products of upper-water-column primary producers (i.e. algae and cyanobacteria). Others derived from anaerobic photoautotrophs and from heterotrophic protozoa (ciliates), which apparently fed partly on Chlorobiaceae. Four groups of n-alkanes produced by algae or cyanobacteria were also recognized based on systematic variations of abundance and isotopic composition with depth. For hydrocarbons probably derived from microalgae, isotopic variations are well correlated with

  1. 15N chemical shift referencing in solid state NMR.

    PubMed

    Bertani, Philippe; Raya, Jésus; Bechinger, Burkhard

    2014-01-01

    Solid-state NMR spectroscopy has much advanced during the last decade and provides a multitude of data that can be used for high-resolution structure determination of biomolecules, polymers, inorganic compounds or macromolecules. In some cases the chemical shift referencing has become a limiting factor to the precision of the structure calculations and we have therefore evaluated a number of methods used in proton-decoupled (15)N solid-state NMR spectroscopy. For (13)C solid-state NMR spectroscopy adamantane is generally accepted as an external standard, but to calibrate the (15)N chemical shift scale several standards are in use. As a consequence the published chemical shift values exhibit considerable differences (up to 22 ppm). In this paper we report the (15)N chemical shift of several commonly used references compounds in order to allow for comparison and recalibration of published data and future work. We show that (15)NH4Cl in its powdered form (at 39.3 ppm with respect to liquid NH3) is a suitable external reference as it produces narrow lines when compared to other reference compounds and at the same time allows for the set-up of cross-polarization NMR experiments. The compound is suitable to calibrate magic angle spinning and static NMR experiments. Finally the temperature variation of (15)NH4Cl chemical shift is reported.

  2. Structure and disorder in basaltic glasses and melts: Insights from high-resolution solid-state NMR study of glasses in diopside-Ca-tschermakite join and diopside-anorthite eutectic composition

    NASA Astrophysics Data System (ADS)

    Park, Sun Young; Lee, Sung Keun

    2012-03-01

    Here, we report experimental results on the effects of composition on the structure of quaternary CaO-MgO-Al2O3-SiO2 (CMAS) glasses in diopside (CaMgSi2O6) and Ca-tschermakite (CaAl2SiO6) join and glass in the diopside-anorthite eutectic composition (Di64An36)—model systems for basaltic melts—using multi-nuclear solid-state NMR. The 27Al 3QMAS NMR spectra of CMAS glasses in diopside-Ca-tschermakite join show predominant [4]Al and a non-negligible fraction of [5]Al. The fraction of [5]Al species increases with increasing mole fraction of diopside (XDiopside). The structurally relevant quadrupolar coupling constant of [4]Al in the glasses decreases with increasing XDiopside, suggesting a decrease in network distortion around [4]Al. Approximately 3.3% of [5]Al is observed for Di64An36 glass, consistent with a previous study (Xue and Kanzaki, 2007). There are also non-negligible fraction of Al-O-Al and significant fractions of Si-O-Al in Di64An36 glass, indicating extensive mixing between Si and Al and violation of the Al-avoidance in basaltic glasses. The 17O 3QMAS NMR spectra of CMAS glasses show that three types of bridging oxygens (BO, Si-O-Si, Al-O-Al, and Si-O-Al) and two types of non-bridging oxygens (NBO, Ca-NBO, and mixed {Ca, Mg}-NBO) are partially resolved. The fraction of NBO in the basaltic glasses decreases with decreasing XDiopside. A presence of the prominent 3Ca-NBO peak (NBO surrounded by three Ca2+ cations) in the CMAS glass at an intermediate compositions (XDiopside = 0.5) suggests non-random distributions of Ca2+ and Mg2+ around NBOs and BOs, characterized either by preferential partitioning of Ca2+ into NBOs and/or structural arrangement toward unmixing of Ca2+ and Mg2+ around NBO. The observed structural changes in the CMAS glasses can provide an improved understanding of their structure-property relationships. The predominance of [4]Al and its extensive mixing with [4]Si is consistent with the negative enthalpy of mixing for CMAS glasses

  3. Protonation of carbon single-walled nanotubes studied using 13C and 1H-13C cross polarization nuclear magnetic resonance and Raman spectroscopies.

    PubMed

    Engtrakul, Chaiwat; Davis, Mark F; Gennett, Thomas; Dillon, Anne C; Jones, Kim M; Heben, Michael J

    2005-12-14

    The reversible protonation of carbon single-walled nanotubes (SWNTs) in sulfuric acid and Nafion was investigated using solid-state nuclear magnetic resonance (NMR) and Raman spectroscopies. Magic-angle spinning (MAS) was used to obtain high-resolution 13C and 1H-13C cross polarization (CP) NMR spectra. The 13C NMR chemical shifts are reported for bulk SWNTs, H2SO4-treated SWNTs, SWNT-Nafion polymer composites, SWNT-AQ55 polymer composites, and SWNTs in contact with water. Protonation occurs without irreversible oxidation of the nanotube substrate via a charge-transfer process. This is the first report of a chemically induced change in a SWNT 13C resonance brought about by a reversible interaction with an acidic proton, providing additional evidence that carbon nanotubes behave as weak bases. Cross polarization was found to be a powerful technique for providing an additional contrast mechanism for studying nanotubes in contact with other chemical species. The CP studies confirmed polarization transfer from nearby protons to nanotube carbon atoms. The CP technique was also applied to investigate water adsorbed on carbon nanotube surfaces. Finally, the degree of bundling of the SWNTs in Nafion films was probed with the 1H-13C CP-MAS technique. PMID:16332107

  4. Scalar operators in solid-state NMR

    SciTech Connect

    Sun, Boqin

    1991-11-01

    Selectivity and resolution of solid-state NMR spectra are determined by dispersion of local magnetic fields originating from relaxation effects and orientation-dependent resonant frequencies of spin nuclei. Theoretically, the orientation-dependent resonant frequencies can be represented by a set of irreducible tensors. Among these tensors, only zero rank tensors (scalar operators) are capable of providing high resolution NMR spectra. This thesis presents a series of new developments in high resolution solid-state NMR concerning the reconstruction of various scalar operators motion in solid C{sub 60} is analyzed.

  5. Solid-state optical microscope

    DOEpatents

    Young, I.T.

    1981-01-07

    A solid state optical microscope is described wherein wide-field and high-resolution images of an object are produced at a rapid rate by utilizing conventional optics with a charge-coupled photodiode array. Means for scanning in one of two orthogonal directions are provided, while the charge-coupled photodiode array scans in the other orthogonal direction. Illumination light from the object is incident upon the photodiodes, creating packets of electrons (signals) which are representative of the illuminated object. The signals are then processed, stored in a memory, and finally displayed as a video signal.

  6. Solid-state NMR spectra of lipid-anchored proteins under magic angle spinning.

    PubMed

    Nomura, Kaoru; Harada, Erisa; Sugase, Kenji; Shimamoto, Keiko

    2014-03-01

    Solid-state NMR is a promising tool for elucidating membrane-related biological phenomena. We achieved the measurement of high-resolution solid-state NMR spectra for a lipid-anchored protein embedded in lipid bilayers under magic angle spinning (MAS). To date, solid-state NMR measurements of lipid-anchored proteins have not been accomplished due to the difficulty in supplying sufficient amount of stable isotope labeled samples in the overexpression of lipid-anchored proteins requiring complex posttranslational modification. We designed a pseudo lipid-anchored protein in which the protein component was expressed in E. coli and attached to a chemically synthesized lipid-anchor mimic. Using two types of membranes, liposomes and bicelles, we demonstrated different types of insertion procedures for lipid-anchored protein into membranes. In the liposome sample, we were able to observe the cross-polarization and the (13)C-(13)C chemical shift correlation spectra under MAS, indicating that the liposome sample can be used to analyze molecular interactions using dipolar-based NMR experiments. In contrast, the bicelle sample showed sufficient quality of spectra through scalar-based experiments. The relaxation times and protein-membrane interaction were capable of being analyzed in the bicelle sample. These results demonstrated the applicability of two types of sample system to elucidate the roles of lipid-anchors in regulating diverse biological phenomena.

  7. Solid State Division

    SciTech Connect

    Green, P.H.; Watson, D.M.

    1989-08-01

    This report contains brief discussions on work done in the Solid State Division of Oak Ridge National Laboratory. The topics covered are: Theoretical Solid State Physics; Neutron scattering; Physical properties of materials; The synthesis and characterization of materials; Ion beam and laser processing; and Structure of solids and surfaces. (LSP)

  8. Cellular Solid-State NMR Investigation of a Membrane Protein Using Dynamic Nuclear Polarization

    PubMed Central

    Yamamoto, Kazutoshi; Caporini, Marc A.; Im, Sang-Choul; Waskell, Lucy; Ramamoorthy, Ayyalusamy

    2014-01-01

    While an increasing number of structural biology studies successfully demonstrate the power of high-resolution structures and dynamics of membrane proteins in fully understanding their function, there is considerable interest in developing NMR approaches to obtain such information in a cellular setting. As long as the proteins inside the living cell tumble rapidly in the NMR timescale, recently developed in-cell solution NMR approaches can be applied towards the determination of 3D structural information. However, there are numerous challenges that need to be overcome to study membrane proteins inside a cell. Research in our laboratory is focused on developing a combination of solid-state NMR and biological approaches to overcome these challenges with a specific emphasis on obtaining high-resolution structural insights into electron transfer biological processes mediated by membrane-bound proteins like mammalian cytochrome b5, cytochrome P450 and cytochrome P450 reductase. In this study, we demonstrate the feasibility of using the signal-enhancement rendered by dynamic nuclear polarization (DNP) magic angle spinning (MAS) NMR spectroscopy for in-cell studies on a membrane-anchored protein. Our experimental results obtained from 13C-labeled membrane-anchored cytochrome b5 in native Escherichia coli cells show a ~16-fold DNP signal enhancement (ε). Further, results obtained from a 2D 13C/13C chemical shift correlation MAS experiment demonstrates that it is highly possible to suppress the background signals from other cellular contents for high-resolution structural studies on membrane proteins. We believe that this study would pave new avenues for high-resolution 3D structural studies on a variety of membrane-associated proteins and their complexes in the cellular context to fully understand their functional roles in physiological processes. PMID:25017802

  9. Dihydroflavanonols from Cedrus deodara, A (13)C NMR study.

    PubMed

    Agrawal, P K; Agarwal, S K; Rastogi, R P; Osterdahal, B G

    1981-09-01

    High resolution (13)C NMR study of taxifolin, cedeodarin, cedrin and their methyl ethers allowed unambiguous placement of the Me in 5,7-dihydroxyflavanonol nucleus, besides providing other valuable information on the substitution pattern in the molecule.

  10. The Organic Solid State.

    ERIC Educational Resources Information Center

    Cowan, Dwaine O.; Wlygul, Frank M.

    1986-01-01

    Reviews interesting and useful electrical, magnetic, and optical properties of the organic solid state. Offers speculation as to areas of fruitful research. Discusses organic superconductors, conducting organic polymers, organic metals, and traces recent history of creation of organic metals. (JM)

  11. Solid state switch

    DOEpatents

    Merritt, Bernard T.; Dreifuerst, Gary R.

    1994-01-01

    A solid state switch, with reverse conducting thyristors, is designed to operate at 20 kV hold-off voltage, 1500 A peak, 1.0 .mu.s pulsewidth, and 4500 pps, to replace thyratrons. The solid state switch is more reliable, more economical, and more easily repaired. The switch includes a stack of circuit card assemblies, a magnetic assist and a trigger chassis. Each circuit card assembly contains a reverse conducting thyristor, a resistor capacitor network, and triggering circuitry.

  12. The effect of sample hydration on 13C CPMAS NMR spectra of fulvic acids

    USGS Publications Warehouse

    Hatcher, P.G.; Wilson, M.A.

    1991-01-01

    Three fulvic acids, two of which have been well studied by a number of other groups (Armadale and Suwannee river fulvic acids) have been examined by high resolution solid-state 13C-NMR techniques to delineate the effect of absorbed water. Two main effects of absorbed water were observed: (1) changes in spin lattice relaxation times in the rotating frame and cross polarization times and (2) total loss of signal so that some fulvic acid is effectively in solution. These results suggest that discrepancies in the literature concerning observed relative signal intensities from different structural groups are due to absorbed water and emphasize the necessity for proper precautionary drying before spectroscopic analysis. ?? 1991.

  13. Solid state switch

    DOEpatents

    Merritt, B.T.; Dreifuerst, G.R.

    1994-07-19

    A solid state switch, with reverse conducting thyristors, is designed to operate at 20 kV hold-off voltage, 1,500 A peak, 1.0 [mu]s pulsewidth, and 4,500 pps, to replace thyratrons. The solid state switch is more reliable, more economical, and more easily repaired. The switch includes a stack of circuit card assemblies, a magnetic assist and a trigger chassis. Each circuit card assembly contains a reverse conducting thyristor, a resistor capacitor network, and triggering circuitry. 6 figs.

  14. Environmentally friendly flame retardants. A detailed solid-state NMR study of melamine orthophosphate.

    PubMed

    Brinkmann, Andreas; Litvinov, Victor M; Kentgens, Arno P M

    2007-12-01

    We used solid-state NMR spectroscopy to gain detailed information about the proton positions, proximities and the hydrogen-bonding network in the environmentally friendly flame retardant melamine orthophosphate (MP). High-resolution proton one- and two-dimensional solid-state NMR spectra were obtained at high external magnetic field in combination with fast magic angle spinning of the sample. Furthermore, we recorded homo- and heteronuclear correlation spectra of types (15)N–(15)N, (1)H–(13)C, (1)H–(15)N and (1)H–(31)P. In addition, we determined the geometry of the NH and NH(2) groups in MP by (15)N–(1)H heteronuclear recoupling experiments.We were able to completely assign the different isotropic chemical shifts in MP. Furthermore, we could identify the protonation of the melamine and orthophosphate moieties. The experimental results are discussed in connection with the structural model obtained by powder X-ray diffraction together with a combined molecular modeling-Rietveld refinement approach (De Ridder et al. Helv. Chim. Acta 2004; 87: 1894). We show that the geometry of the NH2 groups can only be successfully estimated by solid-state NMR. PMID:18157843

  15. Solid-state nuclear magnetic resonance structural studies of proteins using paramagnetic probes.

    PubMed

    Jaroniec, Christopher P

    2012-01-01

    Determination of three-dimensional structures of biological macromolecules by magic-angle spinning (MAS) solid-state NMR spectroscopy is hindered by the paucity of nuclear dipolar coupling-based restraints corresponding to distances exceeding 5 Å. Recent MAS NMR studies of uniformly (13)C,(15)N-enriched proteins containing paramagnetic centers have demonstrated the measurements of site-specific nuclear pseudocontact shifts and spin relaxation enhancements, which report on electron-nucleus distances up to ~20 Å. These studies pave the way for the application of such long-distance paramagnetic restraints to protein structure elucidation and analysis of protein-protein and protein-ligand interactions in the solid phase. Paramagnetic species also facilitate the rapid acquisition of high resolution and sensitivity multidimensional solid-state NMR spectra of biomacromolecules using condensed data collection schemes, and characterization of solvent-accessible surfaces of peptides and proteins. In this review we discuss some of the latest applications of magic-angle spinning NMR spectroscopy in conjunction with paramagnetic probes to the structural studies of proteins in the solid state.

  16. Solid-State Devices.

    ERIC Educational Resources Information Center

    Sutliff, Ronald D.; And Others

    This self-study course is designed to familiarize Marine Corps enlisted personnel with the principles of solid-state devices and their functions. The course contains four study units. Each study unit begins with a general objective, which is a statement of what the student should learn from the unit. The study units are divided into numbered work…

  17. Solid State Lighting

    SciTech Connect

    Hastbacka, Mildred; Dieckmann, John; Bouza, Antonio

    2013-03-30

    The article discusses solid state lighting technologies. This topic was covered in two previous ASHRAE Journal columns (2010). This article covers advancements in technologies and the associated efficacies. The life-cycle, energy savings and market potential of these technologies are addressed as well.

  18. Preparation of uniformly isotope labeled KcsA for solid state NMR: Expression, purification, reconstitution into liposomes and functional assay

    PubMed Central

    Bhate, Manasi P.; Wylie, Benjamin J.; Thompson, Ameer; Tian, Lin; Nimigean, Crina; McDermott, Ann E.

    2013-01-01

    We report the expression, purification, liposome reconstitution and functional validation of uniformly 13C and 15N isotope labeled KcsA, a bacterial potassium channel that has high homology with mammalian channels, for solid-state NMR studies. The expression and purification is optimized for an average yield of ~ 35–40 milligrams per liter of M9 media in a time-efficient way. The protein purity is confirmed by gel electrophoresis and the protein concentration is quantified by UV-Vis absorption spectroscopy. Protocols to efficiently reconstitute KcsA into liposomes are also presented. The presence of liposomes is confirmed by cryo-electron microscopy images and the effect of magic angle spinning on liposome packing is shown. High-resolution solid-state NMR spectra of uniformly isotope labeled KcsA in these liposomes reveal that our protocol yields to a very homogenous KcsA sample with high signal to noise and several well-resolved residues in NMR spectra. Electrophysiology of our samples before and after solid-state NMR show that channel function and selectivity remain intact after the solid-state NMR. PMID:23916531

  19. Solid State Laser

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Titan-CW Ti:sapphire (titanium-doped sapphire) tunable laser is an innovation in solid-state laser technology jointly developed by the Research and Solid State Laser Divisions of Schwartz Electro-optics, Inc. (SEO). SEO is producing the laser for the commercial market, an outgrowth of a program sponsored by Langley Research Center to develop Ti:sapphire technology for space use. SEO's Titan-CW series of Ti:sapphire tunable lasers have applicability in analytical equipment designed for qualitative analysis of carbohydrates and proteins, structural analysis of water, starch/sugar analyses, and measurements of salt in meat. Further applications are expected in semiconductor manufacture, in medicine for diagnosis and therapy, and in biochemistry.

  20. Tunable solid state lasers

    SciTech Connect

    Hammerling, R.; Budgor, A.B.; Pinto, A.

    1985-01-01

    This book presents the papers given at a conference on solid state lasers. Topics considered at the conference included transition-metal-doped lasers, line-narrowed alexandrite lasers, NASA specification, meteorological lidars, laser materials spectroscopy, laser pumped single pass gain, vibronic laser materials growth, crystal growth methods, vibronic laser theory, cross-fertilization through interdisciplinary fields, and laser action of color centers in diamonds.

  1. Solid state oxygen sensor

    DOEpatents

    Garzon, Fernando H.; Chung, Brandon W.; Raistrick, Ian D.; Brosha, Eric L.

    1996-01-01

    Solid state oxygen sensors are provided with a yttria-doped zirconia as an electrolyte and use the electrochemical oxygen pumping of the zirconia electrolyte. A linear relationship between oxygen concentration and the voltage arising at a current plateau occurs when oxygen accessing the electrolyte is limited by a diffusion barrier. A diffusion barrier is formed herein with a mixed electronic and oxygen ion-conducting membrane of lanthanum-containing perovskite or zirconia-containing fluorite. A heater may be used to maintain an adequate oxygen diffusion coefficient in the mixed conducting layer.

  2. Solid state oxygen sensor

    DOEpatents

    Garzon, F.H.; Chung, B.W.; Raistrick, I.D.; Brosha, E.L.

    1996-08-06

    Solid state oxygen sensors are provided with a yttria-doped zirconia as an electrolyte and use the electrochemical oxygen pumping of the zirconia electrolyte. A linear relationship between oxygen concentration and the voltage arising at a current plateau occurs when oxygen accessing the electrolyte is limited by a diffusion barrier. A diffusion barrier is formed herein with a mixed electronic and oxygen ion-conducting membrane of lanthanum-containing perovskite or zirconia-containing fluorite. A heater may be used to maintain an adequate oxygen diffusion coefficient in the mixed conducting layer. 4 figs.

  3. Solid state devices

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Solid State Device research program is directed toward developing innovative devices for space remote and in-situ sensing, and for data processing. Innovative devices can result from the standard structures in innovative materials such as low and high temperature superconductors, strained layer superlattices, or diamond films. Innovative devices can also result from innovative structures achieved using electron tunneling or nanolithography in standard materials. A final step is to use both innovative structures and innovative materials. A new area of emphasis is the miniaturization of sensors and instruments molded by using the techniques of electronic device fabrication to micromachine silicon into micromechanical and electromechanical sensors and actuators.

  4. High resolution triple resonance micro magic angle spinning NMR spectroscopy of nanoliter sample volumes.

    PubMed

    Brauckmann, J Ole; Janssen, J W G Hans; Kentgens, Arno P M

    2016-02-14

    To be able to study mass-limited samples and small single crystals, a triple resonance micro-magic angle spinning (μMAS) probehead for the application of high-resolution solid-state NMR of nanoliter samples was developed. Due to its excellent rf performance this allows us to explore the limits of proton NMR resolution in strongly coupled solids. Using homonuclear decoupling we obtain unprecedented (1)H linewidths for a single crystal of glycine (Δν(CH2) = 0.14 ppm) at high field (20 T) in a directly detected spectrum. The triple channel design allowed the recording of high-resolution μMAS (13)C-(15)N correlations of [U-(13)C-(15)N] arginine HCl and shows that the superior (1)H resolution opens the way for high-sensitivity inverse detection of heteronuclei even at moderate spinning speeds and rf-fields. Efficient decoupling leads to long coherence times which can be exploited in many correlation experiments.

  5. Packaging of solid state devices

    DOEpatents

    Glidden, Steven C.; Sanders, Howard D.

    2006-01-03

    A package for one or more solid state devices in a single module that allows for operation at high voltage, high current, or both high voltage and high current. Low thermal resistance between the solid state devices and an exterior of the package and matched coefficient of thermal expansion between the solid state devices and the materials used in packaging enables high power operation. The solid state devices are soldered between two layers of ceramic with metal traces that interconnect the devices and external contacts. This approach provides a simple method for assembling and encapsulating high power solid state devices.

  6. sup 13 C-enriched ribonucleosides: Synthesis and application of sup 13 C- sup 1 H and sup 13 C- sup 13 C spin-coupling constants to assess furanose and N-glycoside bond conformations

    SciTech Connect

    Kline, P.C.; Serianni, A.S. )

    1990-09-26

    Adenosine (1), cytidine (2), guanosine (3), and uridine (4) have been prepared chemically with {sup 13}C enrichment (99 atom %) at C1{prime} and C2{prime} of the ribose ring. Reliable synthetic protocols have been developed to permit access to millimole quantities of labeled ribonucleosides required for structural studies of stable isotopically labeled oligonucleotides and for in vivo metabolism studies. High-resolution {sup 1}H and {sup 13}C NMR spectra of the enriched ribonucleosides have been obtained, and {sup 13}C-{sup 13}C and {sup 13}C-{sup 1}H spin-coupling constants have been measured for pathways within the {beta}-D-ribofuranose ring and across the N-glycoside bond. Related couplings were determined in methyl {alpha}- and {beta}-D-riboruanosides (5,6), and in two conformationally constrained nucleosides, 2,2{prime}-anhydro-(1-{beta}-D-arabinofuranosyl)uracil (7) and 2{prime},3{prime}-O-isopropylidene-2,5{prime}-O-cyclouridine (8). The latter data were used to construct a crude Karplus curve for the {sup 13}C-C-N-{sup 13}C coupling pathway across the N-glycoside bond in 1-4. {sup 1}H-{sup 1}H, {sup 13}C-{sup 1}H, and {sup 13}C-{sup 13}C coupling data are used to evaluate current models describing the conformational dynamics of 1-4 in aqueous solution.

  7. Solid state television camera

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The design, fabrication, and tests of a solid state television camera using a new charge-coupled imaging device are reported. An RCA charge-coupled device arranged in a 512 by 320 format and directly compatible with EIA format standards was the sensor selected. This is a three-phase, sealed surface-channel array that has 163,840 sensor elements, which employs a vertical frame transfer system for image readout. Included are test results of the complete camera system, circuit description and changes to such circuits as a result of integration and test, maintenance and operation section, recommendations to improve the camera system, and a complete set of electrical and mechanical drawing sketches.

  8. Solid state power controllers

    NASA Technical Reports Server (NTRS)

    Gibbs, R. S.

    1973-01-01

    The rationale, analysis, design, breadboarding and testing of the incremental functional requirements are reported that led to the development of prototype 1 and 5 Amp dc and 1 Amp ac solid state power controllers (SSPC's). The SSPC's are to be considered for use as a replacement of electro-mechanical relays and circuit breakers in future spacecraft and aircraft. They satisfy the combined function of both the relay and circuit breaker and can be remotely controlled by small signals, typically 10 mA, 5 to 28 Vdc. They have the advantage over conventional relay/circuit breaker systems in that they can be located near utilization equipment and the primary ac or dc bus. The low level control, trip indication and status signals can be circuited by small guage wire for control, computer interface, logic, electrical multiplexing, unboard testing, and power management and distribution purposes. This results in increased system versatility at appreciable weight saving and increased reliability.

  9. Solid state rapid thermocycling

    SciTech Connect

    Beer, Neil Reginald; Spadaccini, Christopher

    2014-05-13

    The rapid thermal cycling of a material is targeted. A solid state heat exchanger with a first well and second well is coupled to a power module. A thermoelectric element is coupled to the first well, the second well, and the power module, is configured to transfer thermal energy from the first well to the second well when current from the power module flows through the thermoelectric element in a first direction, and is configured to transfer thermal energy from the second well to the first well when current from the power module flows through the thermoelectric element in a second direction. A controller may be coupled to the thermoelectric elements, and may switch the direction of current flowing through the thermoelectric element in response to a determination by sensors coupled to the wells that the amount of thermal energy in the wells falls below or exceeds a pre-determined threshold.

  10. Position sensitive solid state detectors

    NASA Astrophysics Data System (ADS)

    Schnatterly, S. E.; Husk, D.

    1986-05-01

    Solid state detectors have been used for years as high quantum efficiency detectors for visible light. In this paper the use of PDA and CCD, solid state detectors, in the X-ray region will be discussed. In particular examples of data in the soft X-ray region are presented. Finally the use of phosphor coatings to enhance the sensitivity of solid state detectors is described.

  11. Solid state power controllers

    NASA Technical Reports Server (NTRS)

    Gibbs, R. S.

    1974-01-01

    Solid state power controllers (SSPC's) are to be considered for use as replacements of electromechanical relays and circuit breakers in future spacecraft and aircraft. They satisfy the combined function of both the relay and circuit breaker and can be remotely controlled by small signals, typically 10 mA, 5 to 28 v(dc). They have the advantage over conventional relay/circuit breaker systems in that they can be located near the utilization equipment and the primary ac or dc bus. The low level control, trip indication and status signals can be circuited by small gauge wire for control, computer interface, logic, electrical multiplexing, onboard testing, power management, and distribution purposes. This results in increased system versatility at appreciable weight saving and increased reliability. Conventional systems require the heavy gage load wiring and the control wiring to be routed from the bus to the load to other remote relay contacts, switches, sensors, etc. and to the circuit breaker located in the flight engineer's compartment for purposes of manual reset.

  12. A Solid State Pyranometer

    NASA Astrophysics Data System (ADS)

    Dumitrescu, Anca Laura; Paulescu, Marius; Ercuta, Aurel

    2015-12-01

    The construction of a solid state device-based pyranometer designated to broadband irradiance measurements is presented in this paper. The device is built on the physical basis that the temperature difference between two bodies of identical shape and external surface area, identically exposed to the incident radiation, but having different absorption and heat transfer coefficients (e.g. one body is painted white and the other is painted black), is proportional to the incident irradiance. This proportionality may be put in evidence if the two bodies consisting of identical arrays of correspondingly painted semiconductor diodes, due to the thermal behaviour of their p-n junction. It is theoretically predicted and experimentally confirmed that the voltage drop across a diode passed through a constant forward current linearly decreases with the temperature of the junction. In other words, a signal proportional to the irradiance of the light source may be obtained via conventional analog electronics. The calibration of the apparatus, as performed by means of a professional device (LP PYRA 03), indicates a good linearity.

  13. High-resolution spectroscopy of the {A}^{1}{\\rm{\\Pi }}(v^{\\prime} =0{--}10){--}{X}^{1}{{\\rm{\\Sigma }}}^{+}(v^{\\prime\\prime} =0) bands in 13C18O: term values, ro-vibrational oscillator strengths and Hönl–London corrections

    NASA Astrophysics Data System (ADS)

    Lemaire, J. L.; Eidelsberg, M.; Heays, A. N.; Gavilan, L.; Federman, S. R.; Stark, G.; Lyons, J. R.; de Oliveira, N.; Joyeux, D.

    2016-08-01

    Our knowledge of astronomical environments containing CO depends on accurate molecular data to reproduce and interpret observations. The constant improvement in UV space instrumentation, both in sensitivity and resolution, requires increasingly detailed laboratory data. Following a long-term experimental campaign at the SOLEIL Synchrotron facility, we have acquired complete datasets on the CO isotopologues in the vacuum ultraviolet. Absorption spectra were recorded using the Fourier-transform spectrometer installed on the DESIRS beamline, providing a resolving power R > 106 in the 8–12 eV range. Such resolution allows the analysis of individual line positions and strengths in electronic transitions and the location of perturbations. We continue our previous work on A–X bands of 12C16O and 13C16O, reporting here measurements for the 13C18O isotopologue. Gas column densities in the differentially-pumped system were calibrated using the B {}1{{{Σ }}}+–X {}1{{{Σ }}}+({v}\\prime =0,v\\prime\\prime =0) band. Absorption bands are analyzed by synthesizing line and band profiles and fitting them to measured spectra. New results for A {}1{{\\Pi }}({v}\\prime =0{--}10)–X {}1{{{Σ }}}+(v\\prime\\prime =0) bands include precise line assignments, term values, band-integrated oscillator strengths as well as individual ro-vibrational oscillator strengths and Hönl–London corrections. For ({v}\\prime =1) our results are compared with earlier studies. The interpretation of mixed perturbing bands, complementing an earlier study, is also presented as well as precise line assignments and term values for the B {}1{{{Σ }}}+–X {}1{{{Σ }}}+(0–0) band calibrator, and the nearby B–X (1–0) and C {}1{{{Σ }}}+–X {}1{{{Σ }}}+(0–0) bands.

  14. Distinguishing polymorphs of the semiconducting pigment copper phthalocyanine by solid-state NMR and Raman spectroscopy.

    PubMed

    Shaibat, Medhat A; Casabianca, Leah B; Siberio-Pérez, Diana Y; Matzger, Adam J; Ishii, Yoshitaka

    2010-04-01

    Cu(II)(phthalocyanine) (CuPc) is broadly utilized as an archetypal molecular semiconductor and is the most widely used blue printing pigment. CuPc crystallizes in six different forms; the chemical and physical properties are substantially modulated by its molecular packing among these polymorphs. Despite the growing importance of this system, spectroscopic identification of different polymorphs for CuPc has posed difficulties. This study presents the first example of spectroscopic distinction of alpha- and beta-forms of CuPc, the most widely used polymorphs, by solid-state NMR (SSNMR) and Raman spectroscopy. (13)C high-resolution SSNMR spectra of alpha- and beta-CuPc using very-fast magic angle spinning (VFMAS) at 20 kHz show that hyperfine shifts sensitively reflect polymorphs of CuPc. The experimental results were confirmed by ab initio chemical shift calculations. (13)C and (1)H SSNMR relaxation times of alpha- and beta-CuPc under VFMAS also showed marked differences, presumably because of the difference in electronic spin correlation times in the two forms. Raman spectroscopy also provided another reliable method of differentiation between the two polymorphs.

  15. Distinguishing Polymorphs of the Semiconducting Pigment Copper Phthalocyanine by Solid-state NMR and Raman Spectroscopy

    PubMed Central

    Shaibat, Medhat A.; Casabianca, Leah B.; Siberio-Pérez, Diana Y.; Matzger, Adam J; Ishii, Yoshitaka

    2010-01-01

    Cu(II)(phthalocyanine) (CuPc) is broadly utilized as an archetypal molecular semiconductor and is the most widely used blue printing pigment. CuPc crystallizes in six different forms; the chemical and physical properties are substantially modulated by its molecular packing among these polymorphs. Despite the growing importance of this system, spectroscopic identification of different polymorphs for CuPc has posed difficulties. This study presents the first example of spectroscopic distinction of α- and β-forms of CuPc, the most widely used polymorphs, by solid-state NMR (SSNMR) and Raman spectroscopy. 13C high-resolution SSNMR spectra of α- and β-CuPc using very-fast magic angle spinning (VFMAS) at 20 kHz show that hyperfine shifts sensitively reflect polymorphs of CuPc. The experimental results were confirmed by ab initio chemical shift calculations. 13C and 1H SSNMR relaxation times of α- and β-CuPc under VFMAS also showed marked differences, presumably because of the difference in electronic spin correlation times in the two forms. Raman spectroscopy also provided another reliable method of differentiation between the two polymorphs. PMID:20225842

  16. /sup 13/C nuclear magnetic resonance studies of cardiac metabolism

    SciTech Connect

    Seeholzer, S.H.

    1985-01-01

    The last decade has witnessed the increasing use of Nuclear Magnetic Resonance (NMR) techniques for following the metabolic fate of compounds specifically labeled with /sup 13/C. The goals of the present study are: (1) to develop reliable quantitative procedures for measuring the /sup 13/C enrichment of specific carbon sites in compounds enriched by the metabolism of /sup 13/C-labeled substrates in rat heart, and (2) to use these quantitative measurements of fractional /sup 13/C enrichment within the context of a mathematical flux model describing the carbon flow through the TCA cycle and ancillary pathways, as a means for obtaining unknown flux parameters. Rat hearts have been perfused in vitro with various combinations of glucose, acetate, pyruvate, and propionate to achieve steady state flux conditions, followed by perfusion with the same substrates labeled with /sup 13/C in specific carbon sites. The hearts were frozen at different times after addition of /sup 13/C-labeled substrates and neutralized perchloric acid extracts were used to obtain high resolution proton-decoupled /sup 13/C NMR spectra at 90.55 MHz. The fractional /sup 13/C enrichment (F.E.) of individual carbon sites in different metabolites was calculated from the area of the resolved resonances after correction for saturation and nuclear Overhauser effects. These F.E. measurements by /sup 13/C NMR were validated by the analysis of /sup 13/C-/sup 1/H scalar coupling patterns observed in /sup 1/H NMR spectra of the extracted metabolites. The results obtained from perfusion of hearts glucose plus either (2-/sup 13/C) acetate or (3-/sup 13/C) pyruvate are similar to those obtained by previous investigators using /sup 14/C-labeled substrates.

  17. A solid state NMR study of layered double hydroxides intercalated with para-amino salicylate, a tuberculosis drug.

    PubMed

    Jensen, Nicholai Daugaard; Bjerring, Morten; Nielsen, Ulla Gro

    2016-09-01

    Para-amino salicylate (PAS), a tuberculosis drug, was intercalated in three different layered double hydroxides (MgAl, ZnAl, and CaAl-LDH) and the samples were studied by multi-nuclear ((1)H, (13)C, and (27)Al) solid state NMR (SSNMR) spectroscopy in combination with powder X-ray diffraction (PXRD), elemental analysis and IR-spectroscopy to gain insight into the bulk and atomic level structure of these LDHs especially with a view to the purity of the LDH-PAS materials and the concentration of impurities. The intercalations of PAS in MgAl-, ZnAl-, and CaAl-LDH's were confirmed by (13)C SSNMR and PXRD. Moreover, (13)C MAS NMR and infrared spectroscopy show that PAS did not decompose during synthesis. Large amounts (20-41%) of amorphous aluminum impurities were detected in the structure using (27)Al single pulse and 3QMAS NMR spectra, which in combination with (1)H single and double quantum experiments also showed that the M(II):Al ratio was higher than predicted from the bulk metal composition of MgAl-PAS and ZnAl-PAS. Moreover, the first high-resolution (1)H SSNMR spectra of a CaAl LDH is reported and assigned using (1)H single and double quantum experiments in combination with (27)Al{(1)H} HETCOR.

  18. High-resolution headlamp

    NASA Astrophysics Data System (ADS)

    Gut, Carsten; Cristea, Iulia; Neumann, Cornelius

    2016-04-01

    The following article shall describe how human vision by night can be influenced. At first, front lighting systems that are already available on the market will be described, followed by their analysis with respect to the positive effects on traffic safety. Furthermore, how traffic safety by night can be increased since the introduction of high resolution headlamps shall be discussed.

  19. High-Resolution Views of Io's Emakong Patera: Latest Galileo Imaging Results

    NASA Technical Reports Server (NTRS)

    Williams, D. A.; Keszthelyi, L. P.; Davies, A. G.; Greeley, R.; Head, J. W., III

    2002-01-01

    This presentation will discuss analyses of the latest Galileo SSI (solid state imaging) high-resolution images of the Emakong lava channels and flow field on Jupiter's moon Io. Additional information is contained in the original extended abstract.

  20. High power solid state lasers

    SciTech Connect

    Weber, H.

    1988-01-01

    These proceedings discuss the following subjects: trends in materials processing with laser radiation; slabs and high power systems; glasses and new crystals; solid state lasers at HOYA Corp.; lamps, resonators and transmission; glasses as active materials for high average power solid state lasers; flashlamp pumped GGG-crystals; alexandrite lasers; designing telescope resonators; mode operation of neodymium: YAG lasers; intracavity frequency doubling with KTP crystal and thermal effects in cylinder lasers.

  1. Solid State Photovoltaic Research Branch

    SciTech Connect

    Not Available

    1990-09-01

    This report summarizes the progress of the Solid State Photovoltaic Research Branch of the Solar Energy Research Institute (SERI) from October 1, 1988, through September 30,l 1989. Six technical sections of the report cover these main areas of SERIs in-house research: Semiconductor Crystal Growth, Amorphous Silicon Research, Polycrystalline Thin Films, III-V High-Efficiency Photovoltaic Cells, Solid-State Theory, and Laser Raman and Luminescence Spectroscopy. Sections have been indexed separately for inclusion on the data base.

  2. Solid State Photovoltaic Research Branch

    NASA Astrophysics Data System (ADS)

    1990-09-01

    This report summarizes the progress of the Solid State Photovoltaic Research Branch of the Solar Energy Research Institute (SERI) from October 1, 1988, through September 30, 1989. Six technical sections of the report cover these main areas of SERIs in-house research: Semiconductor Crystal Growth, Amorphous Silicon Research, Polycrystalline Thin Films, III-V High-Efficiency Photovoltaic Cells, Solid-State Theory, and Laser Raman and Luminescence Spectroscopy. Sections have been indexed separately for inclusion on the data base.

  3. Spatially resolved solid-state MAS-NMR-spectroscopy.

    PubMed

    Scheler, U; Schauss, G; Blümich, B; Spiess, H W

    1996-07-01

    A comprehensive account of spatially resolved solid-state MAS NMR of 13C is given. A device generating field gradients rotating synchronously with the magic angle spinner is described. Spatial resolution and sensitivity are compared for phase and frequency encoding of spatial information. The suppression of spinning sidebands is demonstrated for both cases. Prior knowledge about the involved materials can be used for the reduction of data from spatially resolved spectra to map chemical structure. Indirect detection via 13C NMR gives access to the information about mobility from proton-wideline spectra. Two-dimensional solid-state spectroscopy with spatial resolution is demonstrated for a rotor synchronized MAS experiment which resolves molecular order as a function of space. By comparison of different experiments the factors affecting the spatial resolution are investigated.

  4. High resolution data acquisition

    DOEpatents

    Thornton, Glenn W.; Fuller, Kenneth R.

    1993-01-01

    A high resolution event interval timing system measures short time intervals such as occur in high energy physics or laser ranging. Timing is provided from a clock (38) pulse train (37) and analog circuitry (44) for generating a triangular wave (46) synchronously with the pulse train (37). The triangular wave (46) has an amplitude and slope functionally related to the time elapsed during each clock pulse in the train. A converter (18, 32) forms a first digital value of the amplitude and slope of the triangle wave at the start of the event interval and a second digital value of the amplitude and slope of the triangle wave at the end of the event interval. A counter (26) counts the clock pulse train (37) during the interval to form a gross event interval time. A computer (52) then combines the gross event interval time and the first and second digital values to output a high resolution value for the event interval.

  5. High resolution data acquisition

    DOEpatents

    Thornton, G.W.; Fuller, K.R.

    1993-04-06

    A high resolution event interval timing system measures short time intervals such as occur in high energy physics or laser ranging. Timing is provided from a clock, pulse train, and analog circuitry for generating a triangular wave synchronously with the pulse train (as seen in diagram on patent). The triangular wave has an amplitude and slope functionally related to the time elapsed during each clock pulse in the train. A converter forms a first digital value of the amplitude and slope of the triangle wave at the start of the event interval and a second digital value of the amplitude and slope of the triangle wave at the end of the event interval. A counter counts the clock pulse train during the interval to form a gross event interval time. A computer then combines the gross event interval time and the first and second digital values to output a high resolution value for the event interval.

  6. High-Resolution Autoradiography

    NASA Technical Reports Server (NTRS)

    Towe, George C; Gomberg, Henry J; Freemen, J W

    1955-01-01

    This investigation was made to adapt wet-process autoradiography to metallurgical samples to obtain high resolution of segregated radioactive elements in microstructures. Results are confined to development of the technique, which was perfected to a resolution of less than 10 microns. The radioactive samples included carbon-14 carburized iron and steel, nickel-63 electroplated samples, a powder product containing nickel-63, and tungsten-185 in N-155 alloy.

  7. Ultra high resolution tomography

    SciTech Connect

    Haddad, W.S.

    1994-11-15

    Recent work and results on ultra high resolution three dimensional imaging with soft x-rays will be presented. This work is aimed at determining microscopic three dimensional structure of biological and material specimens. Three dimensional reconstructed images of a microscopic test object will be presented; the reconstruction has a resolution on the order of 1000 A in all three dimensions. Preliminary work with biological samples will also be shown, and the experimental and numerical methods used will be discussed.

  8. The development of solid-state NMR of membrane proteins

    PubMed Central

    Opella, Stanley J.

    2014-01-01

    Most biological functions are carried out in supramolecular assemblies. As a result of their slow reorientation in solution, these assemblies have been resistant to the widely employed solution NMR approaches. The development of solid-state NMR to first of all overcome the correlation time problem and then obtain informative high-resolution spectra of proteins in supramolecular assemblies, such as virus particles and membranes, is described here. High resolution solid-state NMR is deeply intertwined with the history of NMR, and the seminal paper was published in 1948. Although the general principles were understood by the end of the 1950s, it has taken more than fifty years for instrumentation and experimental methods to become equal to the technical problems presented by the biological assemblies of greatest interest. It is now possible to obtain atomic resolution structures of viral coat proteins in virus particles and membrane proteins in phospholipid bilayers by oriented sample solid-state NMR methods. The development of this aspect of the field of solid-state NMR is summarized in this review article. PMID:26069880

  9. Modern solid state laser materials

    SciTech Connect

    Krupke, W.F.

    1984-06-20

    This document contains visual aids used in an invited talk entitled Modern Solid State Laser Materials, presented at the Conference on Lasers and Electro-Optics (CLEO) held in Anaheim, California, on June 20, 1984. Interest at LLNL in solid state lasers focuses on evaluating the potential of solid state laser media for high average power applications, including inertial fusion power production. This talk identifies the relevant bulk material parameters characterizing average power capacity and uses chromium and neodymium co-doped gadolinium scandium gallium garnet (Nd:Cr:GSGG) as an example of a laser material with improved laser properties relative to Nd:YAG (plausible large-scale growth, more efficient spectral coupling to xenon flashlamp radiation, reduced stimulated emission cross section, adequate thermal shock and optical damage threshold parameters, etc.). Recently measured spectroscopic, kinetic, and thermo-mechanical properties of Nd:Cr:GSGG are given.

  10. 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. PMID:26203019

  11. 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.

  12. Selective excitation enables assignment of proton resonances and {sup 1}H-{sup 1}H distance measurement in ultrafast magic angle spinning solid state NMR spectroscopy

    SciTech Connect

    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 {sup 1}H resonances becomes absolutely necessary. Herein, we propose an approach to identify different proton peaks by using dipolar-coupled heteronuclei such as {sup 13}C or {sup 15}N. In this method, after the initial preparation of proton magnetization and cross-polarization to {sup 13}C nuclei, transverse magnetization of desired {sup 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 {sup 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 {sup 1}H-{sup 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.

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

    NASA Astrophysics Data System (ADS)

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-07-01

    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 1H resonances becomes absolutely necessary. Herein, we propose an approach to identify different proton peaks by using dipolar-coupled heteronuclei such as 13C or 15N. In this method, after the initial preparation of proton magnetization and cross-polarization to 13C nuclei, transverse magnetization of desired 13C 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 13C 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 1H-1H 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.

  14. Solid-state lithium battery

    DOEpatents

    Ihlefeld, Jon; Clem, Paul G; Edney, Cynthia; Ingersoll, David; Nagasubramanian, Ganesan; Fenton, Kyle Ross

    2014-11-04

    The present invention is directed to a higher power, thin film lithium-ion electrolyte on a metallic substrate, enabling mass-produced solid-state lithium batteries. High-temperature thermodynamic equilibrium processing enables co-firing of oxides and base metals, providing a means to integrate the crystalline, lithium-stable, fast lithium-ion conductor lanthanum lithium tantalate (La.sub.1/3-xLi.sub.3xTaO.sub.3) directly with a thin metal foil current collector appropriate for a lithium-free solid-state battery.

  15. Modeling an in-register, parallel "iowa" aβ fibril structure using solid-state NMR data from labeled samples with rosetta.

    PubMed

    Sgourakis, Nikolaos G; Yau, Wai-Ming; Qiang, Wei

    2015-01-01

    Determining the structures of amyloid fibrils is an important first step toward understanding the molecular basis of neurodegenerative diseases. For β-amyloid (Aβ) fibrils, conventional solid-state NMR structure determination using uniform labeling is limited by extensive peak overlap. We describe the characterization of a distinct structural polymorph of Aβ using solid-state NMR, transmission electron microscopy (TEM), and Rosetta model building. First, the overall fibril arrangement is established using mass-per-length measurements from TEM. Then, the fibril backbone arrangement, stacking registry, and "steric zipper" core interactions are determined using a number of solid-state NMR techniques on sparsely (13)C-labeled samples. Finally, we perform Rosetta structure calculations with an explicitly symmetric representation of the system. We demonstrate the power of the hybrid Rosetta/NMR approach by modeling the in-register, parallel "Iowa" mutant (D23N) at high resolution (1.2Å backbone rmsd). The final models are validated using an independent set of NMR experiments that confirm key features.

  16. Versatile solid-state relay

    NASA Technical Reports Server (NTRS)

    Fox, D. A.

    1977-01-01

    Solid-state relay (SSR), containing multinode control logic, is operated as normally open, normally closed, or latched. Moreover several can be paralleled to form two-pole or double-throw relays. Versatile unit ends need to design custom control circuit for every relay application. Technique can be extended to incorporate selectable time delay, on operation or release, or pulsed output.

  17. Solid-state radioluminescent compositions

    DOEpatents

    Clough, Roger L.; Gill, John T.; Hawkins, Daniel B.; Renschler, Clifford L.; Shepodd, Timothy J.; Smith, Henry M.

    1991-01-01

    A solid state radioluminescent composition for light source comprises an optically clear polymer organic matrix containing tritiated organic materials and dyes capable of "red" shifting primary scintillation emissions from the polymer matrix. The tritiated organic materials are made by reducing, with tritium, an unsaturated organic compound that prior to reduction contains olefinic or alkynylic bonds.

  18. Coal structure at reactive sites by sup 1 H- sup 13 C- sup 19 F double cross polarization (DCP)/MAS sup 13 C NMR spectroscopy

    SciTech Connect

    Hagaman, E.W.; Woody, M.C. )

    1989-01-01

    The solid state NMR technique, {sup 1}H-{sup 13}C-{sup 31}P double cross polarization (DCP)/MAS {sup 13}C-NMR spectroscopy, uses the direct dipolar interaction between {sup 13}C-{sup 31}P spin pairs in organophosphorus substances to identify the subset of carbons within a spherical volume element of 0.4 nm radius centered on the {sup 31}P atom. In combination with chemical manipulation of coals designed to introduce phosphorus containing functionality into the organic matrix, the NMR experiment becomes a method to examine selectively the carbon bonding network at the reactive sites in the coal. This approach generates a statistical structure description of the coal at the reaction centers in contrast to bulk carbon characterization using conventional {sup 1}H-{sup 13}C CP/MAS {sup 13}C NMR spectroscopy. 3 refs.

  19. Solid-state NMR investigations of cellulose structure and interactions with matrix polysaccharides in plant primary cell walls.

    PubMed

    Wang, Tuo; Hong, Mei

    2016-01-01

    Until recently, the 3D architecture of plant cell walls was poorly understood due to the lack of high-resolution techniques for characterizing the molecular structure, dynamics, and intermolecular interactions of the wall polysaccharides in these insoluble biomolecular mixtures. We introduced multidimensional solid-state NMR (SSNMR) spectroscopy, coupled with (13)C labelling of whole plants, to determine the spatial arrangements of macromolecules in near-native plant cell walls. Here we review key evidence from 2D and 3D correlation NMR spectra that show relatively few cellulose-hemicellulose cross peaks but many cellulose-pectin cross peaks, indicating that cellulose microfibrils are not extensively coated by hemicellulose and all three major polysaccharides exist in a single network rather than two separate networks as previously proposed. The number of glucan chains in the primary-wall cellulose microfibrils has been under active debate recently. We show detailed analysis of quantitative (13)C SSNMR spectra of cellulose in various wild-type (WT) and mutant Arabidopsis and Brachypodium primary cell walls, which consistently indicate that primary-wall cellulose microfibrils contain at least 24 glucan chains.

  20. Sensitivity and resolution enhancement of oriented solid-state NMR: Application to membrane proteins

    PubMed Central

    Gopinath, T.; Mote, Kaustubh R.; Veglia, Gianluigi

    2013-01-01

    Oriented solid-state NMR (O-ssNMR) spectroscopy is a major technique for the high-resolution analysis of the structure and topology of transmembrane proteins in native-like environments. Unlike magic angle spinning (MAS) techniques, O-ssNMR spectroscopy requires membrane protein preparations that are uniformly oriented (mechanically or magnetically) so that anisotropic NMR parameters, such as dipolar and chemical shift interactions, can be measured to determine structure and orientation of membrane proteins in lipid bilayers. Traditional sample preparations involving mechanically aligned lipids often result in short relaxation times which broaden the 15N resonances and encumber the manipulation of nuclear spin coherences. The introduction of lipid bicelles as membrane mimicking systems has changed this scenario, and the more favorable relaxation properties of membrane protein 15N and 13C resonances make it possible to develop new, more elaborate pulse sequences for higher spectral resolution and sensitivity. Here, we describe our recent progress in the optimization of O-ssNMR pulse sequences. We explain the theory behind these experiments, demonstrate their application to small and medium size proteins, and describe the technical details for setting up these new experiments on the new generation of NMR spectrometers. PMID:24160761

  1. High Resolution Laboratory Spectroscopy

    NASA Astrophysics Data System (ADS)

    Brünken, S.; Schlemmer, S.

    2016-05-01

    In this short review we will highlight some of the recent advancements in the field of high-resolution laboratory spectroscopy that meet the needs dictated by the advent of highly sensitive and broadband telescopes like ALMA and SOFIA. Among these is the development of broadband techniques for the study of complex organic molecules, like fast scanning conventional absorption spectroscopy based on multiplier chains, chirped pulse instrumentation, or the use of synchrotron facilities. Of similar importance is the extension of the accessible frequency range to THz frequencies, where many light hydrides have their ground state rotational transitions. Another key experimental challenge is the production of sufficiently high number densities of refractory and transient species in the laboratory, where discharges have proven to be efficient sources that can also be coupled to molecular jets. For ionic molecular species sensitive action spectroscopic schemes have recently been developed to overcome some of the limitations of conventional absorption spectroscopy. Throughout this review examples demonstrating the strong interplay between laboratory and observational studies will be given.

  2. High Resolution Doppler Imager

    NASA Technical Reports Server (NTRS)

    Hays, Paul B.

    1999-01-01

    This report summarizes the accomplishments of the High Resolution Doppler Imager (HRDI) on UARS spacecraft during the period 4/l/96 - 3/31/99. During this period, HRDI operation, data processing, and data analysis continued, and there was a high level of vitality in the HRDI project. The HRDI has been collecting data from the stratosphere, mesosphere, and lower thermosphere since instrument activation on October 1, 1991. The HRDI team has stressed three areas since operations commenced: 1) operation of the instrument in a manner which maximizes the quality and versatility of the collected data; 2) algorithm development and validation to produce a high-quality data product; and 3) scientific studies, primarily of the dynamics of the middle atmosphere. There has been no significant degradation in the HRDI instrument since operations began nearly 8 years ago. HRDI operations are fairly routine, although we have continued to look for ways to improve the quality of the scientific product, either by improving existing modes, or by designing new ones. The HRDI instrument has been programmed to collect data for new scientific studies, such as measurements of fluorescence from plants, measuring cloud top heights, and lower atmosphere H2O.

  3. Solid-state membrane module

    DOEpatents

    Gordon, John Howard; Taylor, Dale M.

    2011-06-07

    Solid-state membrane modules comprising at least one membrane unit, where the membrane unit has a dense mixed conducting oxide layer, and at least one conduit or manifold wherein the conduit or manifold comprises a dense layer and at least one of a porous layer and a slotted layer contiguous with the dense layer. The solid-state membrane modules may be used to carry out a variety of processes including the separating of any ionizable component from a feedstream wherein such ionizable component is capable of being transported through a dense mixed conducting oxide layer of the membrane units making up the membrane modules. For ease of construction, the membrane units may be planar.

  4. Solid-state membrane module

    SciTech Connect

    Hinklin, Thomas Ray; Lewinsohn, Charles Arthur

    2015-06-30

    A module for separating oxygen from an oxygen-containing gaseous mixture comprising planar solid-state membrane units, each membrane unit comprising planar dense mixed conducting oxides layers, planar channel-free porous support layers, and one or more planar intermediate support layers comprising at least one channeled porous support layer. The porosity of the planar channeled porous support layers is less than the porosity of the planar channel-free porous support layers.

  5. Solid-State Nuclear Power

    NASA Technical Reports Server (NTRS)

    George, Jeffrey A.

    2012-01-01

    A strategy for "Solid-State" Nuclear Power is proposed to guide development of technologies and systems into the second 50 years of nuclear spaceflight. The strategy emphasizes a simple and highly integrated system architecture with few moving parts or fluid loops; the leverage of modern advances in materials, manufacturing, semiconductors, microelectromechanical and nanotechnology devices; and the targeted advancement of high temperature nuclear fuels, materials and static power conversion to enable high performance from simple system topologies.

  6. Solid state cell with anolyte

    SciTech Connect

    Barnette, L. H.; Liang, C. C.

    1985-06-25

    A solid state cell having a solid cathode, a solid electrolyte, and a solid anolyte comprised of at least 50% by volume of ionically conductive materials such as the electrolye and 50% or less by volume of an active metal. The anolyte is either the cell anode or alternatively the anolyte is an additional structural member within said cell positioned between an anode, comprised of the same active metal, and the solid electrolyte.

  7. Radiation sensitive solid state switch

    NASA Technical Reports Server (NTRS)

    Hutto, R. J. (Inventor)

    1973-01-01

    A mechanically operable solid state switch suited for use in achieving a variable circuit-switching function is described. This switch is characterized by an annular array of photoresponsive switching devices, disposed in communication with an included source of radiation, and a plurality of interchangeable, mechanically operable interrupter disks. Each disk has a predetermined pattern of transparent and opaque portions. Operative displacement of each disk serves to make and break selected electrical circuits through the photo responsive devices of said array.

  8. Solid state electrochemical current source

    DOEpatents

    Potanin, Alexander Arkadyevich; Vedeneev, Nikolai Ivanovich

    2002-04-30

    A cathode and a solid state electrochemical cell comprising said cathode, a solid anode and solid fluoride ion conducting electrolyte. The cathode comprises a metal oxide and a compound fluoride containing at least two metals with different valences. Representative compound fluorides include solid solutions of bismuth fluoride and potassium fluoride; and lead fluoride and potassium fluoride. Representative metal oxides include copper oxide, lead oxide, manganese oxide, vanadium oxide and silver oxide.

  9. Disentangling crystallographic inequivalence and crystallographic forms of L-arginine by one- and two-dimensional solid-state NMR spectroscopy.

    PubMed

    Herbert-Pucheta, Jose-Enrique; Colaux, Henri; Bodenhausen, Geoffrey; Tekely, Piotr

    2011-12-29

    Overlapping (13)C or (15)N solid-state NMR spectra from crystallographically different forms of L-arginine hydrochloride can be separated by exploiting differential proton T(1) relaxation in conjunction with cross-polarization. Dipolar (13)C-(13)C and (15)N-(15)N two-dimensional correlation experiments reveal resonances belonging to crystallographically and magnetically inequivalent molecules.

  10. Solid state amorphization kinetic of alpha lactose upon mechanical milling.

    PubMed

    Caron, Vincent; Willart, Jean-François; Lefort, Ronan; Derollez, Patrick; Danède, Florence; Descamps, Marc

    2011-11-29

    It has been previously reported that α-lactose could be totally amorphized by ball milling. In this paper we report a detailed investigation of the structural and microstructural changes by which this solid state amorphization takes place. The investigations have been performed by Powder X-ray Diffraction, Solid State Nuclear Magnetic Resonance ((13)C CP-MAS) and Differential Scanning Calorimetry. The results reveal the structural complexity of the material in the course of its amorphization so that it cannot be considered as a simple mixture made of a decreasing crystalline fraction and an increasing amorphous fraction. Heating this complexity can give rise to a fully nano-crystalline material. The results also show that chemical degradations upon heating are strongly connected to the melting process. PMID:21983262

  11. High Resolution Formaldehyde Photochemistry

    NASA Astrophysics Data System (ADS)

    Ernest, C. T.; Bauer, D.; Hynes, A. J.

    2010-12-01

    Formaldehyde (HCHO) is the most abundant and most important organic carbonyl compound in the atmosphere. The sources of formaldehyde are the oxidation of methane, isoprene, acetone, and other volatile organic compounds (VOCs); fossil fuel combustion; and biomass burning. The dominant loss mechanism for formaldehyde is photolysis which occurs via two pathways: (R1) HCHO + hv → HCO + H (R2) HCHO + hv → H2 + CO The first pathway (R1) is referred to as the radical channel, while the second pathway (R2) is referred to as the molecular channel. The products of both pathways play a significant role in atmospheric chemistry. The CO that is produced in the molecular channel undergoes further oxidation to produce CO2. Under atmospheric conditions, the H atom and formyl radical that are produced in the radical channel undergo rapid reactions with O2 to produce the hydroperoxyl radical (HO2) via (R3) and (R4). (R3) HCO + O2 → HO2 + CO (R4) H + O2 → HO2 Thus, for every photon absorbed, the photolysis of formaldehyde can contribute one CO2 molecule to the global greenhouse budget or two HO2 radicals to the tropospheric HOx (OH + HO2) cycle. The HO2 radicals produced during formaldehyde photolysis have also been implicated in the formation of photochemical smog. The HO2 radicals act as radical chain carriers and convert NO to NO2, which ultimately results in the catalytic production of O3. Constraining the yield of HO2 produced via HCHO photolysis is essential for improving tropospheric chemistry models. In this study, both the absorption cross section and the quantum yield of the radical channel (R1) were measured at high resolution over the tropospherically relevant wavelength range 304-330 nm. For the cross section measurements a narrow linewidth Nd:YAG pumped dye laser was used with a multi-pass cell. Partial pressures of HCHO were kept below 0.3 torr. Simultaneous measurement of OH LIF in a flame allowed absolute calibration of the wavelength scale. Pressure

  12. Solution and solid state NMR approaches to draw iron pathways in the ferritin nanocage.

    PubMed

    Lalli, Daniela; Turano, Paola

    2013-11-19

    Ferritins are intracellular proteins that can store thousands of iron(III) ions as a solid mineral. These structures autoassemble from four-helix bundle subunits to form a hollow sphere and are a prototypical example of protein nanocages. The protein acts as a reservoir, encapsulating iron as ferric oxide in its central cavity in a nontoxic and bioavailable form. Scientists have long known the structural details of the protein shell, owing to very high resolution X-ray structures of the apoform. However, the atomic level mechanism governing the multistep biomineralization process remained largely elusive. Through analysis of the chemical behavior of ferritin mutants, chemists have found the role of some residues in key reaction steps. Using Mössbauer and XAS, they have identified some di-iron intermediates of the catalytic reaction trapped by rapid freeze quench. However, structural information about the iron interaction sites remains scarce. The entire process is governed by a number of specific, but weak, interactions between the protein shell and the iron species moving across the cage. While this situation may constitute a major problem for crystallography, NMR spectroscopy represents an optimal tool to detect and characterize transient species involving soluble proteins. Regardless, NMR analysis of the 480 kDa ferritin represents a real challenge. Our interest in ferritin chemistry inspired us to use an original combination of solution and solid state approaches. While the highly symmetric structure of the homo-24-mer frog ferritin greatly simplifies the spectra, the large protein size hinders the efficient coherence transfer in solution, thus preventing the sequence specific assignments. In contrast, extensive (13)C-spin diffusion makes the solution (13)C-(13)C NOESY experiment our gold standard to monitor protein side chains both in the apoprotein alone and in its interaction with paramagnetic iron species, inducing line broadening on the resonances of

  13. Nanoparticle size and shape characterization with Solid State Nanopores

    NASA Astrophysics Data System (ADS)

    Nandivada, Santoshi; Benamara, Mourad; Li, Jiali

    2015-03-01

    Solid State Nanopores are widely used in a variety of single molecule studies including DNA and biomolecule detection based on the principle of Resistive Pulse technique. This technique is based on electrophoretically driving charged particles through 35-60 nm solid state nanopores. The translocation of these particles produces current blockage events that provide an insight to the properties of the translocation particles and the nanopore. In this work we study the current blockage events produced by ~ 30nm negatively charged PS nanoparticles through Silicon Nitride solid state nanopores. We show how the current blockage amplitudes and durations are related to the ratio of the volume of the particle to the volume of the pore, the shape of the particle, charge of the particle and the nanopore surface, salt concentration, solution pH, and applied voltage. The solid-state nanopores are fabricated by a combination of Focus Ion Beam and low energy Ion beams in silicon nitride membranes. High resolution TEM is used to measure the 3D geometry of the nanopores and a finite element analysis program (COMSOL) is used to simulate the experimental results.

  14. High resolution time interval meter

    DOEpatents

    Martin, A.D.

    1986-05-09

    Method and apparatus are provided for measuring the time interval between two events to a higher resolution than reliability available from conventional circuits and component. An internal clock pulse is provided at a frequency compatible with conventional component operating frequencies for reliable operation. Lumped constant delay circuits are provided for generating outputs at delay intervals corresponding to the desired high resolution. An initiation START pulse is input to generate first high resolution data. A termination STOP pulse is input to generate second high resolution data. Internal counters count at the low frequency internal clock pulse rate between the START and STOP pulses. The first and second high resolution data are logically combined to directly provide high resolution data to one counter and correct the count in the low resolution counter to obtain a high resolution time interval measurement.

  15. Chemical Symbolism and the Solid State

    ERIC Educational Resources Information Center

    Jensen, William B.

    1977-01-01

    Discusses the coordinated polyhedra approach to teaching the solid state. A solid is viewed as a collection of coordination complexes. Also proposes a method of extending the current chemical symbolism to include structural facts of solid state chemistry. (MLH)

  16. Neglect of Solid State Chemistry Scored

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1974

    1974-01-01

    At a recent symposium concerning the teaching of solid state chemistry in the classroom, many educators indicated that important areas of solid state chemistry were being neglected in college curricula. (RH)

  17. Solid state electrochromic light modulator

    SciTech Connect

    Cogan, S.F.; Rauh, R.D.

    1990-07-03

    An all solid-state variable transmission electrochromic device has a source of charge compensating ions. An inorganic oxide counter electrode film which on reduction with the accompanying insertion of the charge compensating ions increases its transmission of light of predetermined wavelength is separated from a primary electrochromic film which on reduction with the accompanying insertion of the charge compensating ions decreases its transmission of light of predetermined wavelength by an insulating electrolyte film that transports the charge compensating ions. First and second electrodes are contiguous with the inorganic oxide counter electrode film and the primary electrochromic film, respectively, and separated by the three films. 4 figs.

  18. Solid state nuclear track detection

    SciTech Connect

    Durrani, S.A.; Bull, R.K.

    1987-01-01

    This book is a basic work on the technique variously known as 'nuclear track analysis', 'track-etch technique', or 'solid state nuclear tract detection'. This has greatly expanded in range, scope and depth since the early 1960's, soon after its discovery, until there is hardly a field now in which it has not found an actual or potential use. Such applications range from archaeology, geology, space physics, medicine and biology to reactor physics and nuclear physics-to name but a few.

  19. Solid state electrochromic light modulator

    DOEpatents

    Cogan, Stuart F.; Rauh, R. David

    1993-01-01

    An all solid-state variable transmission electrochromic device has a source of charge compensating ions. An inorganic oxide counterelectrode film which on reduction with the accompanying insertion of the charge compensating ions increases its transmission of light of predetermined wavelength is separated from a primary electrochromic film which on reduction with the accompanying insertion of the charge compensating ions decreases its transmission of light of predetermined wavelength by an insulating electrolyte film that transports the charge compensating ions. First and second electrodes are contiguous with the inorganic oxide counter electrode film and the primary electrochromic film, respectively, and separated by the three films.

  20. Solid-State Personal Dosimetry

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Fralick, Gustave C.; Wrbanek, Susan Y.

    2005-01-01

    This document is a web site page, and a data sheet about Personal protection (i.e., space suits) presented to the Radiation and Micrometeoroid Mitigation Technology Focus Group meeting. The website describes the work of the PI to improve solid state personal radiation dosimetry. The data sheet presents work on the active personal radiation detection system that is to provide real-time local radiation exposure information during EVA. Should undue exposure occur, knowledge of the dynamic intensity conditions during the exposure will allow more precise diagnostic assessment of the potential health risk to the exposed individual.

  1. Solid state electrochromic light modulator

    DOEpatents

    Cogan, Stuart F.; Rauh, R. David

    1990-01-01

    An all solid-state variable transmission electrochromic device has a source of charge compensating ions. An inorganic oxide counterelectrode film which on reduction with the accompanying insertion of the charge compensating ions increases its transmission of light of predetermined wavelength is separated from a primary electrochromic film which on reduction with the accompanying insertion of the charge compensating ions decreases its transmission of light of predetermined wavelength by an insulating electrolyte film that transports the charge compensating ions. First and second electrodes are contiguous with the inorganic oxide counter electrode film and the primary electrochromic film, respectively, and separated by the three films.

  2. Solid state electrochromic light modulator

    DOEpatents

    Cogan, Stuart F.; Rauh, R. David

    1993-12-07

    An all solid-state variable transmission electrochromic device has a source of charge compensating ions. An inorganic oxide counterelectrode film which on reduction with the accompanying insertion of the charge compensating ions increases its transmission of light of predetermined wavelength is separated from a primary electrochromic film which on reduction with the accompanying insertion of the charge compensating ions decreases its transmission of light of predetermined wavelength by an insulating electrolyte film that transports the charge compensating ions. First and second electrodes are contiguous with the inorganic oxide counter electrode film and the primary electrochromic film, respectively, and separated by the three films.

  3. Solid-State NMR Studies of Chemically Lithiated CFx

    PubMed Central

    Leifer, N. D.; Johnson, V. S.; Ben-Ari, R.; Gan, H.; Lehnes, J. M.; Guo, R.; Lu, W.; Muffoletto, B. C.; Reddy, T.; Stallworth, P. E.; Greenbaum, S. G.

    2010-01-01

    Three types of fluorinated carbon, all in their original form and upon sequential chemical lithiations via n-butyllithium, were investigated by 13C and 19F solid-state NMR methods. The three starting CFx materials [where x = 1 (nominally)] were fiber based, graphite based, and petroleum coke based. The aim of the current study was to identify, at the atomic/molecular structural level, factors that might account for differences in electrochemical performance among the different kinds of CFx. Differences were noted in the covalent F character among the starting compounds and in the details of LiF production among the lithiated samples. PMID:20676233

  4. Solid-State NMR Studies of Chemically Lithiated CF.

    PubMed

    Leifer, N D; Johnson, V S; Ben-Ari, R; Gan, H; Lehnes, J M; Guo, R; Lu, W; Muffoletto, B C; Reddy, T; Stallworth, P E; Greenbaum, S G

    2010-01-01

    Three types of fluorinated carbon, all in their original form and upon sequential chemical lithiations via n-butyllithium, were investigated by (13)C and (19)F solid-state NMR methods. The three starting CF(x) materials [where x = 1 (nominally)] were fiber based, graphite based, and petroleum coke based. The aim of the current study was to identify, at the atomic/molecular structural level, factors that might account for differences in electrochemical performance among the different kinds of CF(x). Differences were noted in the covalent F character among the starting compounds and in the details of LiF production among the lithiated samples.

  5. Contamination and solid state welds.

    SciTech Connect

    Mills, Bernice E.

    2007-05-01

    Since sensitivity to contamination is one of the verities of solid state joining, there is a need for assessing contamination of the part(s) to be joined, preferably nondestructively while it can be remedied. As the surfaces that are joined in pinch welds are inaccessible and thus provide a greater challenge, most of the discussion is of the search for the origin and effect of contamination on pinch welding and ways to detect and mitigate it. An example of contamination and the investigation and remediation of such a system is presented. Suggestions are made for techniques for nondestructive evaluation of contamination of surfaces for other solid state welds as well as for pinch welds. Surfaces that have good visual access are amenable to inspection by diffuse reflection infrared Fourier transform (DRIFT) spectroscopy. Although other techniques are useful for specific classes of contaminants (such as hydrocarbons), DRIFT can be used most classes of contaminants. Surfaces such as the interior of open tubes or stems that are to be pinch welded can be inspected using infrared reflection spectroscopy. It must be demonstrated whether or not this tool can detect graphite based contamination, which has been seen in stems. For tubes with one closed end, the technique that should be investigated is emission infrared spectroscopy.

  6. Solid-state proton conductors

    SciTech Connect

    Jewulski, J.R.; Osif, T.L.; Remick, R.J.

    1990-12-01

    The purpose of this program was to survey the field of solid-state proton conductors (SSPC), identify conductors that could be used to develop solid-state fuel cells suitable for use with coal derived fuel gases, and begin the experimental research required for the development of these fuel cells. This document covers the following topics: the history of developments and current status of the SSPC, including a review of proton conducting electrolyte structures, the current status of the medium temperature SSPC development, electrodes for moderate temperature (SSPC) fuel cell, basic material and measurement techniques applicable for SSPC development, modeling and optimization studies. Correlation and optimization studies, to include correlation studies on proton conduction and oxide cathode optimization for the SSPC fuel cell. Experiments with the SSPC fuel cells including the fabrication of the electrolyte disks, apparatus for conducting measurements, the strontium-cerium based electrolyte, the barium-cerium based electrolyte with solid foil electrodes, the barium-cerium based electrolyte with porous electrodes, and conduction mechanisms. 164 refs., 27 figs., 13 tabs.

  7. Natural-abundance solid-state 2H NMR spectroscopy at high magnetic field.

    PubMed

    Aliev, Abil E; Mann, Sam E; Iuga, Dinu; Hughes, Colan E; Harris, Kenneth D M

    2011-06-01

    High-resolution solid-state (2)H NMR spectroscopy provides a method for measuring (1)H NMR chemical shifts in solids and is advantageous over the direct measurement of high-resolution solid-state (1)H NMR spectra, as it requires only the application of routine magic angle sample spinning (MAS) and routine (1)H decoupling methods, in contrast to the requirement for complex pulse sequences for homonuclear (1)H decoupling and ultrafast MAS in the case of high-resolution solid-state (1)H NMR. However, a significant obstacle to the routine application of high-resolution solid-state (2)H NMR is the very low natural abundance of (2)H, with the consequent problem of inherently low sensitivity. Here, we explore the feasibility of measuring (2)H MAS NMR spectra of various solids with natural isotopic abundances at high magnetic field (850 MHz), focusing on samples of amino acids, peptides, collagen, and various organic solids. The results show that high-resolution solid-state (2)H NMR can be used successfully to measure isotropic (1)H chemical shifts in favorable cases, particularly for mobile functional groups, such as methyl and -N(+)H(3) groups, and in some cases phenyl groups. Furthermore, we demonstrate that routine (2)H MAS NMR measurements can be exploited for assessing the relative dynamics of different functional groups in a molecule and for assessing whole-molecule motions in the solid state. The magnitude and field-dependence of second-order shifts due to the (2)H quadrupole interaction are also investigated, on the basis of analysis of simulated and experimental (1)H and (2)H MAS NMR spectra of fully deuterated and selectively deuterated samples of the α polymorph of glycine at two different magnetic field strengths.

  8. Solid-State Recorders Enhance Scientific Data Collection

    NASA Technical Reports Server (NTRS)

    2010-01-01

    Under Small Business Innovation Research (SBIR) contracts with Goddard Space Flight Center, SEAKR Engineering Inc., of Centennial, Colorado, crafted a solid-state recorder (SSR) to replace the tape recorder onboard a Spartan satellite carrying NASA's Inflatable Antenna Experiment. Work for that mission and others has helped SEAKR become the world leader in SSR technology for spacecraft. The company has delivered more than 100 systems, more than 85 of which have launched onboard NASA, military, and commercial spacecraft including imaging satellites that provide much of the high-resolution imagery for online mapping services like Google Earth.

  9. 6-Aminopenicillanic acid revisited: A combined solid state NMR and in silico refinement

    NASA Astrophysics Data System (ADS)

    Aguiar, Daniel Lima Marques de; San Gil, Rosane Aguiar da Silva; Alencastro, Ricardo Bicca de; Souza, Eugenio Furtado de; Borré, Leandro Bandeira; Vaiss, Viviane da Silva; Leitão, Alexandre Amaral

    2016-09-01

    13C/15N (experimental and ab initio) solid-state NMR was used to achieve an affordable way to improve hydrogen refinement of 6-aminopenicillanic acid (6-APA) structure. The lattice effect on the isotropic chemical shifts was probed by using two different magnetic shielding calculations: isolated molecules and periodic crystal structure. The electron density difference maps of optimized and non-optimized structures were calculated in order to investigate the interactions inside the 6-APA unit cell. The 13C and 15N chemical shifts assignments were unambiguously stablished. In addition, some of the literature 13C resonances ambiguities could be properly solved.

  10. Solid State Lighting Program (Falcon)

    SciTech Connect

    Meeks, Steven

    2012-06-30

    Over the past two years, KLA-Tencor and partners successfully developed and deployed software and hardware tools that increase product yield for High Brightness LED (HBLED) manufacturing and reduce product development and factory ramp times. This report summarizes our development effort and details of how the results of the Solid State Light Program (Falcon) have started to help HBLED manufacturers optimize process control by enabling them to flag and correct identified killer defect conditions at any point of origin in the process manufacturing flow. This constitutes a quantum leap in yield management over current practice. Current practice consists of die dispositioning which is just rejection of bad die at end of process based upon probe tests, loosely assisted by optical in-line monitoring for gross process deficiencies. For the first time, and as a result of our Solid State Lighting Program, our LED manufacturing partners have obtained the software and hardware tools that optimize individual process steps to control killer defects at the point in the processes where they originate. Products developed during our two year program enable optimized inspection strategies for many product lines to minimize cost and maximize yield. The Solid State Lighting Program was structured in three phases: i) the development of advanced imaging modes that achieve clear separation between LED defect types, improves signal to noise and scan rates, and minimizes nuisance defects for both front end and back end inspection tools, ii) the creation of defect source analysis (DSA) software that connect the defect maps from back-end and front-end HBLED manufacturing tools to permit the automatic overlay and traceability of defects between tools and process steps, suppress nuisance defects, and identify the origin of killer defects with process step and conditions, and iii) working with partners (Philips Lumileds) on product wafers, obtain a detailed statistical correlation of automated

  11. Study of solid state photomultiplier

    NASA Technical Reports Server (NTRS)

    Hays, K. M.; Laviolette, R. A.

    1987-01-01

    Available solid state photomultiplier (SSPM) detectors were tested under low-background, low temperature conditions to determine the conditions producing optimal sensitivity in a space-based astronomy system such as a liquid cooled helium telescope in orbit. Detector temperatures varied between 6 and 9 K, with background flux ranging from 10 to the 13th power to less than 10 to the 6th power photons/square cm-s. Measured parameters included quantum efficiency, noise, dark current, and spectral response. Experimental data were reduced, analyzed, and combined with existing data to build the SSPM data base included herein. The results were compared to analytical models of SSPM performance where appropriate models existed. Analytical models presented here were developed to be as consistent with the data base as practicable. Significant differences between the theory and data are described. Some models were developed or updated as a result of this study.

  12. Solid state sciences committee forum

    NASA Astrophysics Data System (ADS)

    Smith, Philip

    1992-05-01

    The 1991 SSSC Forum was conducted under the auspices of the Board on Physics and Astronomy's Solid State Sciences Committee (SSSC) and cosponsored with the National Materials Advisory Board (NMAB). The Forum was the culmination of a year-long dissemination effort following up the NCR study Materials Science and Engineering for the 1990s that was released in September of 1989 and successfully brought together experts and policy makers in the field of advanced materials processing to discuss issues pertinent to the field. Support for the Forum was provided by the Air Force office of Scientific Research (AFOSR), the Department of Energy (DOE), the National Science Foundation (NSF), and the office of Naval Research (ONR).

  13. Novel solid state sensor platform

    NASA Astrophysics Data System (ADS)

    Colvin, Arthur E., Jr.; Bargeron, C. Brent; Phillips, Terry E.; Miragliotta, Joseph A.; Givens, Robert B.

    1998-05-01

    A unique solid-state optical sensor configuration has been invented that can serve as a development platform for a host of chemical and biochemical sensors in either gaseous or liquid environments. We present results from measurements from the first adaptation of the device to oxygen sensing via fluorescence quenching and note the distinct advantages over existing electrochemical and more recent fiber-optic methods. The platform technology itself features greatly enhanced energy efficiency, high sensitivity, low-power consumption, ease of miniaturization, low cost, high-volume manufacturability using standard methods, very fast response/recovery profiles, and high reliability. The oxygen sensor embodiment has been demonstrated to operate well over the temperature range from -20 to 50 degrees C, not to be interfered with by other common gases including water vapor at high levels, and capable of response times less than 100 milliseconds.

  14. Spin dynamics in the modulation frame: application to homonuclear recoupling in magic angle spinning solid-state NMR.

    PubMed

    De Paëpe, Gaël; Lewandowski, Józef R; Griffin, Robert G

    2008-03-28

    We introduce a family of solid-state NMR pulse sequences that generalizes the concept of second averaging in the modulation frame and therefore provides a new approach to perform magic angle spinning dipolar recoupling experiments. Here, we focus on two particular recoupling mechanisms-cosine modulated rotary resonance (CMpRR) and cosine modulated recoupling with isotropic chemical shift reintroduction (COMICS). The first technique, CMpRR, is based on a cosine modulation of the rf phase and yields broadband double-quantum (DQ) (13)C recoupling using >70 kHz omega(1,C)/2pi rf field for the spinning frequency omega(r)/2=10-30 kHz and (1)H Larmor frequency omega(0,H)/2pi up to 900 MHz. Importantly, for p>or=5, CMpRR recouples efficiently in the absence of (1)H decoupling. Extension to lower p values (3.513)C recoupling and (1)H decoupling. The second technique, COMICS, involves low power (13)C irradiation that induces simultaneous recoupling of the (13)C DQ dipolar and isotropic chemical shift terms. In contrast to CMpRR, where the DQ bandwidth (approximately 30 kHz at omega(0,H)/2pi=750 MHz) covers the entire (13)C spectral width, COMICS recoupling, through the reintroduction of the isotropic chemical shift, is selective with respect to the carrier frequency, having a typical bandwidth of approximately 100 Hz. This approach is intended as a general frequency selective method circumventing dipolar truncation (supplementary to R(2) experiments). These new gamma-encoded sequences with attenuated rf requirements extend the applicability of homonuclear recoupling techniques to new regimes--high spinning and Larmor frequencies--and therefore should be of major

  15. 13C-1H dipolar-driven 13C-13C recoupling without 13C rf irradiation in nuclear magnetic resonance of rotating solids

    NASA Astrophysics Data System (ADS)

    Takegoshi, K.; Nakamura, Shinji; Terao, Takehiko

    2003-02-01

    Two recently proposed 13C-13C recoupling methods under magic angle spinning (MAS), resonant interference recoupling (RIR), and 13C-1H dipolar-assisted rotational resonance (DARR), are examined on a common theoretical foundation using the average Hamiltonian theory. In both methods, a rf field is applied on not 13C but 1H to recouple the 13C-1H dipolar interactions, and spectral overlap necessary to conserve energy for 13C-13C polarization transfer is achieved by the 13C-1H dipolar line broadening. While DARR employs time-independent 13C-1H interactions recoupled by suitable rf irradiation to 1H spins, RIR uses time-dependent 13C-1H interactions modulated appropriately by 1H rf irradiation. There are two distinct cases where 13C-1H line broadening realizes 13C-13C spectral overlap. For a pair of a carbonyl or aromatic carbon and an aliphatic carbon, spectral overlap can be achieved between one of the spinning sidebands of the former 13C resonance and the 13C-1H dipolar powder pattern of the latter. On the other hand for a pair of spins with a small chemical shift difference, the two center bands are overlapped with each other due to 13C-1H dipolar broadening. For the former, we show that both RIR and DARR occur in the first order, while for the latter, DARR recoupling is appreciable for time-independent 13C-1H interactions. We refer to the former DARR as the first-order DARR recoupling and the latter as the second-order DARR. Experimentally, we examined the following 13C-1H recoupling methods for DARR: 1H CW irradiation fulfilling a rotary-resonance condition or a modulatory-resonance condition, and 1H π pulses applied synchronously to MAS. For RIR, the FSLG-m2m¯m sequence is applied to 1H. Several one-dimensional DARR and RIR experiments were done for N-acetyl[1,2-13C, 15N] DL-valine, and [2,3-13C] L-alanine. It was found that the polarization transfer rate for RIR is larger than that for DARR except for fast spinning, while the rate for DARR is less sensitive to

  16. Exploration of structure and function in biomolecules through solid-state NMR and computational methods

    NASA Astrophysics Data System (ADS)

    Heider, Elizabeth M.

    Solid-State Nuclear Magnetic Resonance (SSNMR) spectroscopy and quantum mechanical calculations are powerful analysis tools. Leveraged independently, each method yields important nuclear and molecular information. Used in concert, SSNMR and computational techniques provide complementary data about the structure of solids. These methods are particularly useful in characterizing the structures of microcrystalline organic compounds and revealing mechanisms of biological activity. Such applications may possess special relevance in analysis of pharmaceutical products; 90% of all pharmaceuticals are marketed as solids and bioactivity is strongly linked with molecular conformation. Accordingly, this dissertation employs both SSNMR and quantum mechanical computation to study three bioactive molecules: citrinin, two forms of Atrasentan (Abt-627), and paclitaxel (Taxol RTM). First, a computational study is utilized to determine the mechanism for unusual antioxidant activity in citrinin. Here, molecular geometries and bond dissociation enthalpies (BDE) of the citrinin O--H groups are calculated from first principles (ab initio). The total molecular Hamiltonian is determined by approximating the individual contributors to energy including electronic energy and contributions from modes of molecular vibration. This study of citrinin clearly identifies specific reaction sites in the active form, establishing the central role of intramolecular hydrogen bonding in this activity. Notably, it is discovered that citrinin itself is not the active species. Instead, a pair of hydrated Michael addition products of citrinin act as radical scavengers via O--H bond dissociation. Next, two separate compounds of the anticancer drug Abt-627 (form I and form II) are examined via SSNMR. The three principal values of the 13C diagonalized chemical shift tensor are acquired through the high resolution 2D experiment, FIREMAT. Isotropic chemical shift assignments are made utilizing both dipolar

  17. 13C CP MAS NMR and GIAO-CHF calculations of coumarins.

    PubMed

    Zolek, Teresa; Paradowska, Katarzyna; Wawer, Iwona

    2003-01-01

    13C cross-polarization magic-angle spinning NMR spectra were recorded for a series of solid coumarins. Ab initio calculations of shielding constants were performed with the use of GIAO-CHF method. The combined CPMAS NMR and theoretical approach was successful in characterizing solid-state conformations of coumarins; a relationship sigma (ppm) = -1.032 xdelta + 205.28 (R(2) = 0.9845) can be used to obtain structural information for coumarins, for which solid-state NMR or crystal structure data are not available.

  18. Preparation of RNA samples with narrow line widths for solid state NMR investigations

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Bardaro, Michael F.; Varani, Gabriele; Drobny, Gary P.

    2012-10-01

    Solid state NMR can provide detailed structural and dynamic information on biological systems that cannot be studied under solution conditions, and can investigate motions which occur with rates that cannot be fully studied by solution NMR. This approach has successfully been used to study proteins, but the application of multidimensional solid state NMR to RNA has been limited because reported line widths have been too broad to execute most multidimensional experiments successfully. A reliable method to generate spectra with narrow line widths is necessary to apply the full range of solid state NMR spectroscopic approaches to RNA. Using the HIV-1 transactivation response (TAR) RNA as a model, we present an approach based on precipitation with polyethylene glycol that improves the line width of 13C signals in TAR from >6 ppm to about 1 ppm, making solid state 2D NMR studies of selectively enriched RNAs feasible at ambient temperature.

  19. Solid-state rechargeable magnesium battery

    DOEpatents

    Shao, Yuyan; Liu, Jun; Liu, Tianbiao; Li, Guosheng

    2016-09-06

    Embodiments of a solid-state electrolyte comprising magnesium borohydride, polyethylene oxide, and optionally a Group IIA or transition metal oxide are disclosed. The solid-state electrolyte may be a thin film comprising a dispersion of magnesium borohydride and magnesium oxide nanoparticles in polyethylene oxide. Rechargeable magnesium batteries including the disclosed solid-state electrolyte may have a coulombic efficiency .gtoreq.95% and exhibit cycling stability for at least 50 cycles.

  20. Solid state safety jumper cables

    DOEpatents

    Kronberg, James W.

    1993-01-01

    Solid state jumper cables for connecting two batteries in parallel, having two bridge rectifiers for developing a reference voltage, a four-input decoder for determining which terminals are to be connected based on a comparison of the voltage at each of the four terminals to the reference voltage, and a pair of relays for effecting the correct connection depending on the determination of the decoder. No connection will be made unless only one terminal of each battery has a higher voltage than the reference voltage, indicating "positive" terminals, and one has a lower voltage than the reference voltage, indicating "negative" terminals, and that, therefore, the two high voltage terminals may be connected and the two lower voltage terminals may be connected. Current flows once the appropriate relay device is closed. The relay device is preferably a MOSFET (metal oxide semiconductor field effect transistor) combined with a series array of photodiodes that develop MOSFET gate-closing potential when the decoder output causes an LED to light.

  1. Solid state safety jumper cables

    DOEpatents

    Kronberg, J.W.

    1993-02-23

    Solid state jumper cables for connecting two batteries in parallel, having two bridge rectifiers for developing a reference voltage, a four-input decoder for determining which terminals are to be connected based on a comparison of the voltage at each of the four terminals to the reference voltage, and a pair of relays for effecting the correct connection depending on the determination of the decoder. No connection will be made unless only one terminal of each battery has a higher voltage than the reference voltage, indicating positive'' terminals, and one has a lower voltage than the reference voltage, indicating negative'' terminals, and that, therefore, the two high voltage terminals may be connected and the two lower voltage terminals may be connected. Current flows once the appropriate relay device is closed. The relay device is preferably a MOSFET (metal oxide semiconductor field effect transistor) combined with a series array of photodiodes that develop MOSFET gate-closing potential when the decoder output causes an LED to light.

  2. Solid state radiative heat pump

    DOEpatents

    Berdahl, Paul H.

    1986-01-01

    A solid state radiative heat pump (10, 50, 70) operable at room temperature (300.degree. K.) utilizes a semiconductor having a gap energy in the range of 0.03-0.25 eV and operated reversibly to produce an excess or deficit of charge carriers as compared to thermal equilibrium. In one form of the invention (10, 70) an infrared semiconductor photodiode (21, 71) is used, with forward or reverse bias, to emit an excess or deficit of infrared radiation. In another form of the invention (50), a homogeneous semiconductor (51) is subjected to orthogonal magnetic and electric fields to emit an excess or deficit of infrared radiation. Three methods of enhancing transmission of radiation through the active surface of the semiconductor are disclosed. In one method, an anti-reflection layer (19) is coated into the active surface (13) of the semiconductor (11), the anti-reflection layer (19) having an index of refraction equal to the square root of that of the semiconductor (11). In the second method, a passive layer (75) is spaced from the active surface (73) of the semiconductor (71) by a submicron vacuum gap, the passive layer having an index of refractive equal to that of the semiconductor. In the third method, a coupler (91) with a paraboloid reflecting surface (92) is in contact with the active surface (13, 53) of the semiconductor (11, 51), the coupler having an index of refraction about the same as that of the semiconductor.

  3. Solid state radiative heat pump

    DOEpatents

    Berdahl, P.H.

    1984-09-28

    A solid state radiative heat pump operable at room temperature (300 K) utilizes a semiconductor having a gap energy in the range of 0.03-0.25 eV and operated reversibly to produce an excess or deficit of change carriers as compared equilibrium. In one form of the invention an infrared semiconductor photodiode is used, with forward or reverse bias, to emit an excess or deficit of infrared radiation. In another form of the invention, a homogenous semiconductor is subjected to orthogonal magnetic and electric fields to emit an excess or deficit of infrared radiation. Three methods of enhancing transmission of radiation the active surface of the semiconductor are disclosed. In one method, an anti-refection layer is coated into the active surface of the semiconductor, the anti-reflection layer having an index of refraction equal to the square root of that of the semiconductor. In the second method, a passive layer is speaced trom the active surface of the semiconductor by a submicron vacuum gap, the passive layer having an index of refractive equal to that of the semiconductor. In the third method, a coupler with a paraboloid reflecting surface surface is in contact with the active surface of the semiconductor, the coupler having an index of refraction about the same as that of the semiconductor.

  4. Solid state electrochromic smart windows

    NASA Astrophysics Data System (ADS)

    1991-03-01

    The structure under development at EIC Laboratories consists of a multilayer stack of thin films, incorporating the two principal electrochemically active elements, the electrochromic (EC) and counter electrode (CE) layers, respectively. The EC layer changes from colorless to a state of reduced transmission on reduction while the CE layer has the opposite (complementary) behavior (or is colorless in both oxidized and reduced states). These are separated by an ion conducting electrolyte. The stack is completed with top and bottom transparent electrodes. The major achievements are as follows: (1) Tunable thermal emittance for the EC layer over a range of 0.2 to 0.8 was demonstrated, indicating the feasibility of surfaces with adjustable heat transfer properties. (2) Thin film ion conductors based on the Li2O/B2O3 and LiNbO3 were developed using thermal and electron beam evaporation with ionic conductivities greater than 10(exp -8) S/cm, fulfilling a major requirement for this component. (3) A variety of improved vanadium oxide-based counter electrode materials were demonstrated and patented which undergo reversible electrochemical Li insertion reactions and which increase their solar transmission on reduction. (4) Devices incorporating a laminated Li+ conducting polymer electrolyte were demonstrated with bleached state visible transmittance of greater than 65 percent and colored state transmittance of less than 15 percent. These devices were tested for greater than 10(exp 4) complete cycles. (5) An all thin film solid state device was demonstrated with a visible transmission range of 65/13 percent, using the component materials developed on this program. The device was tested for greater than 3000 complete cycles without degradation. A fabrication sequence was specified which forms the basis of initial production cost estimates. (6) Window modeling studies have been used to compare the relative performance of amorphous and crystalline WO3-based electrochromic

  5. A solid state streak camera

    NASA Astrophysics Data System (ADS)

    Kleinfelder, Stuart; Kwiatkowski, Kris; Shah, Ashish

    2005-03-01

    A monolithic solid-state streak camera has been designed and fabricated in a standard 0.35 μm, 3.3V, thin-oxide digital CMOS process. It consists of a 1-D linear array of 150 integrated photodiodes, followed by fast analog buffers and on-chip, 150-deep analog frame storage. Each pixel's front-end consists of an n-diffusion / p-well photodiode, with fast complementary reset transistors, and a source-follower buffer. Each buffer drives a line of 150 sample circuits per pixel, with each sample circuit consisting of an n-channel sample switch, a 0.1 pF double-polysilicon sample capacitor, a reset switch to definitively clear the capacitor, and a multiplexed source-follower readout buffer. Fast on-chip sample clock generation was designed using a self-timed break-before-make operation that insures the maximum time for sample settling. The electrical analog bandwidth of each channels buffer and sampling circuits was designed to exceed 1 GHz. Sampling speeds of 400 M-frames/s have been achieved using electrical input signals. Operation with optical input signals has been demonstrated at 100 MHz sample rates. Sample output multiplexing allows the readout of all 22,500 samples (150 pixels times 150 samples per pixel) in about 3 ms. The chip"s output range was a maximum of 1.48 V on a 3.3V supply voltage, corresponding to a maximum 2.55 V swing at the photodiode. Time-varying output noise was measured to be 0.51 mV, rms, at 100 MHz, for a dynamic range of ~11.5 bits, rms. Circuit design details are presented, along with the results of electrical measurements and optical experiments with fast pulsed laser light sources at several wavelengths.

  6. Measuring doubly 13C-substituted ethane by mass spectrometry

    NASA Astrophysics Data System (ADS)

    Clog, M.; Ling, C.; Eiler, J. M.

    2012-12-01

    Ethane (C2H6) is present in non-negligible amounts in most natural gas reservoirs and is used to produce ethylene for petrochemical industries. It is one of the by-products of lipid metabolism and is the arguably simplest molecule that can manifest multiple 13C substitutions. There are several plausible controls on the relative abundances of 13C2H6 in natural gases: thermodynamically controlled homogeneous isotope exchange reactions analogous to those behind carbonate clumped isotope thermometry; inheritance from larger biomolecules that under thermal degradation to produce natural gas; mixing of natural gases that differ markedly in bulk isotopic composition; or combinations of these and/or other, less expected fractionations. There is little basis for predicting which of these will dominate in natural samples. Here, we focus on an analytical techniques that will provide the avenue for exploring these phenomena. The method is based on high-resolution gas source isotope ratio mass spectrometry, using the Thermo 253-Ultra (a new prototype mass spectrometer). This instrument achieves the mass resolution (M/Δ M) up to 27,000, permitting separation of the isobaric interferences of potential contaminants and isotopologues of an analtye or its fragments which share a cardinal mass. We present techniques to analyze several isotopologues of molecular and fragment ions of C2H6. The critical isobaric separations for our purposes include: discrimination of 13C2H6 from 13C12CDH5 at mass 32 and separation of the 13CH3 fragment from 12CH4 at mass 16, both requiring at least a mass resolution of 20000 to make an adequate measurement. Other obvious interferences are either cleanly separated (e.g., O2, O) or accounted for by peak-stripping (CH3OH on mass 32 and NH2 on mass 16). We focus on a set of measurements which constrain: the doubly-substituted isotopologue, 13C2H6, and the 13CH3/12CH3 ratio of the methyl fragment, which constrains the bulk δ 13C. Similar methods can be

  7. New guidelines for δ13C measurements

    USGS Publications Warehouse

    Coplen, Tyler B.; Brand, Willi A.; Gehre, Matthias; Groning, Manfred; Meijer, Harro A. J.; Toman, Blaza; Verkouteren, R. Michael

    2006-01-01

    Consistency of δ13C measurements can be improved 39−47% by anchoring the δ13C scale with two isotopic reference materials differing substantially in 13C/12C. It is recommended thatδ13C values of both organic and inorganic materials be measured and expressed relative to VPDB (Vienna Peedee belemnite) on a scale normalized by assigning consensus values of −46.6‰ to L-SVEC lithium carbonate and +1.95‰ to NBS 19 calcium carbonate. Uncertainties of other reference material values on this scale are improved by factors up to two or more, and the values of some have been notably shifted:  the δ13C of NBS 22 oil is −30.03%.

  8. Characterization of uniformly and atom-specifically 13C-labeled heparin and heparan sulfate polysaccharide precursors using 13C NMR spectroscopy and ESI mass spectrometry

    PubMed Central

    Nguyen, Thao K. N.; Tran, Vy M.; Victor, Xylophone V.; Skalicky, Jack J.; Kuberan, Balagurunathan

    2010-01-01

    The biological actions of heparin and heparan sulfate, two structurally related glycosaminoglycans, depend on the organization of the complex heparanome. Due to the structural complexity of the heparanome, the sequence of variably sulfonated uronic acid and glucosamine residues is usually characterized by the analysis of smaller oligosaccharide and disaccharide fragments. Even characterization of smaller heparin/heparan sulfate oligosaccharide or disaccharide fragments using simple 1D 1H NMR spectroscopy is often complicated by the extensive signal overlap. 13C NMR signals, on the other hand, overlap less and therefore, 13C NMR spectroscopy can greatly facilitate the structural elucidation of the complex heparanome and provide finer insights into the structural basis for biological functions. This is the first report of the preparation of anomeric carbon-specific 13C-labeled heparin/heparan sulfate precursors from the Escherichia coli K5 strain. Uniformly 13C- and 15N-labeled precursors were also produced and characterized by 13C NMR spectroscopy. Mass spectrometric analysis of enzymatically fragmented disaccharides revealed that anomeric carbon-specific labeling efforts resulted in a minor loss/scrambling of 13C in the precursor backbone, whereas uniform labeling efforts resulted in greater than 95% 13C isotope enrichment in the precursor backbone. These labeled precursors provided high-resolution NMR signals with great sensitivity and set the stage for studying the heparanome–proteome interactions. PMID:20832774

  9. Solid State Reactor Final Report

    SciTech Connect

    Mays, G.T.

    2004-03-10

    The Solid State Reactor (SSR) is an advanced reactor concept designed to take advantage of Oak Ridge National Laboratory's (ORNL's) recently developed graphite foam that has enhanced heat transfer characteristics and excellent high-temperature mechanical properties, to provide an inherently safe, self-regulated, source of heat for power and other potential applications. This work was funded by the U.S. Department of Energy's Nuclear Energy Research Initiative (NERI) program (Project No. 99-064) from August 1999 through September 30, 2002. The initial concept of utilizing the graphite foam as a basis for developing an advanced reactor concept envisioned that a suite of reactor configurations and power levels could be developed for several different applications. The initial focus was looking at the reactor as a heat source that was scalable, independent of any heat removal/power conversion process. These applications might include conventional power generation, isotope production and destruction (actinides), and hydrogen production. Having conducted the initial research on the graphite foam and having performed the scoping parametric analyses from neutronics and thermal-hydraulic perspectives, it was necessary to focus on a particular application that would (1) demonstrate the viability of the overall concept and (2) require a reasonably structured design analysis process that would synthesize those important parameters that influence the concept the most as part of a feasible, working reactor system. Thus, the application targeted for this concept was supplying power for remote/harsh environments and a design that was easily deployable, simplistic from an operational standpoint, and utilized the new graphite foam. Specifically, a 500-kW(t) reactor concept was pursued that is naturally load following, inherently safe, optimized via neutronic studies to achieve near-zero reactivity change with burnup, and proliferation resistant. These four major areas of research

  10. ANL high-resolution injector

    SciTech Connect

    Minehara, E.; Kutschera, W.; Hartog, P.D.; Billquist, P.; Liu, Z.

    1986-05-01

    The ANL (Argonne National Laboratory) high-resolution injector has been installed to obtain higher mass resolution and higher preacceleration, and to utilize effectively the full mass range of ATLAS (Argonne tandem linac accelerator system). Preliminary results of the first beam test are reported briefly. The design and performance, in particular a high-mass-resolution magnet with aberration compensation, are discussed.

  11. High resolution digital delay timer

    DOEpatents

    Martin, Albert D.

    1988-01-01

    Method and apparatus are provided for generating an output pulse following a trigger pulse at a time delay interval preset with a resolution which is high relative to a low resolution available from supplied clock pulses. A first lumped constant delay (20) provides a first output signal (24) at predetermined interpolation intervals corresponding to the desired high resolution time interval. Latching circuits (26, 28) latch the high resolution data (24) to form a first synchronizing data set (60). A selected time interval has been preset to internal counters (142, 146, 154) and corrected for circuit propagation delay times having the same order of magnitude as the desired high resolution. Internal system clock pulses (32, 34) count down the counters to generate an internal pulse delayed by an interval which is functionally related to the preset time interval. A second LCD (184) corrects the internal signal with the high resolution time delay. A second internal pulse is then applied to a third LCD (74) to generate a second set of synchronizing data (76) which is complementary with the first set of synchronizing data (60) for presentation to logic circuits (64). The logic circuits (64) further delay the internal output signal (72) to obtain a proper phase relationship of an output signal (80) with the internal pulses (32, 34). The final delayed output signal (80) thereafter enables the output pulse generator (82) to produce the desired output pulse (84) at the preset time delay interval following input of the trigger pulse (10, 12).

  12. Advanced very high resolution radiometer

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The advanced very high resolution radiometer development program is considered. The program covered the design, construction, and test of a breadboard model, engineering model, protoflight model, mechanical structural model, and a life test model. Special bench test and calibration equipment was also developed for use on the program.

  13. Dynamic nuclear polarization-enhanced 13C NMR spectroscopy of static biological solids

    NASA Astrophysics Data System (ADS)

    Potapov, Alexey; Yau, Wai-Ming; Tycko, Robert

    2013-06-01

    We explore the possibility of using dynamic nuclear polarization (DNP) to enhance signals in structural studies of biological solids by solid state NMR without sample spinning. Specifically, we use 2D 13C-13C exchange spectroscopy to probe the peptide backbone torsion angles (ϕ, ψ) in a series of selectively 13C-labeled 40-residue β-amyloid (Aβ1-40) samples, in both fibrillar and non-fibrillar states. Experiments are carried out at 9.39 T and 8 K, using a static double-resonance NMR probe and low-power microwave irradiation at 264 GHz. In frozen solutions of Aβ1-40 fibrils doped with DOTOPA-TEMPO, we observe DNP signal enhancement factors of 16-21. We show that the orientation- and frequency-dependent spin polarization exchange between sequential backbone carbonyl 13C labels can be simulated accurately using a simple expression for the exchange rate, after experimentally determined homogeneous 13C lineshapes are incorporated in the simulations. The experimental 2D 13C-13C exchange spectra place constraints on the ϕ and ψ angles between the two carbonyl labels. Although the data are not sufficient to determine ϕ and ψ uniquely, the data do provide non-trivial constraints that could be included in structure calculations. With DNP at low temperatures, 2D 13C-13C exchange spectra can be obtained from a 3.5 mg sample of Aβ1-40 fibrils in 4 h or less, despite the broad 13C chemical shift anisotropy line shapes that are observed in static samples.

  14. Dynamic nuclear polarization-enhanced 13C NMR spectroscopy of static biological solids

    PubMed Central

    Potapov, Alexey; Yau, Wai-Ming; Tycko, Robert

    2013-01-01

    We explore the possibility of using dynamic nuclear polarization (DNP) to enhance signals in structural studies of biological solids by solid state NMR without sample spinning. Specifically, we use 2D 13C-13C exchange spectroscopy to probe the peptide backbone torsion angles (ϕ,ψ) in a series of selectively 13C-labeled 40-residue β-amyloid (Aβ1–40) samples, in both fibrillar and non-fibrillar states. Experiments are carried out at 9.39 T and 8 K, using a static double-resonance NMR probe and low-power microwave irradiation at 264 GHz. In frozen solutions of Aβ1–40 fibrils doped with DOTOPA-TEMPO, we observe DNP signal enhancement factors of 16–21. We show that the orientation- and frequency-dependent spin polarization exchange between sequential backbone carbonyl 13C labels can be simulated accurately using a simple expression for the exchange rate, after experimentally determined homogeneous 13C lineshapes are incorporated in the simulations. The experimental 2D 13C-13C exchange spectra place constraints on the ϕ and ψ angles between the two carbonyl labels. Although the data are not sufficient to determine ϕ and ψ uniquely, the data do provide non-trivial constraints that could be included in structure calculations. With DNP at low temperatures, 2D 13C-13C exchange spectra can be obtained from a 3.5 mg sample of Aβ1–40 fibrils in 4 hr or less, despite the broad 13C chemical shift anisotropy line shapes that are observed in static samples. PMID:23562665

  15. Solid state recorders for airborne reconnaissance

    NASA Astrophysics Data System (ADS)

    Klang, Mark R.

    2003-08-01

    Solid state recorders have become the recorder of choice for meeting airborne ruggedized requirements for reconnaissance and flight test. The cost of solid state recorders have decreased over the past few years that they are now less expense than the traditional high speed tape recorders. CALCULEX, Inc manufactures solid state recorders called MONSSTR (Modular Non-volatile Solid State Recorder). MONSSTR is being used on many different platforms such as F/A-22, Global Hawk, F-14, F-15, F-16, U-2, RF-4, and Tornado. This paper will discuss the advantages of using solid state recorders to meet the airborne reconnaissance requirement and the ability to record instrumentation data. The CALCULEX recorder has the ability to record sensor data and flight test data in the same chassis. This is an important feature because it eliminates additional boxes on the aircraft. The major advantages to using a solid state recorder include; reliability, small size, light weight, and power. Solid state recorders also have a larger storage capacity and higher bandwidth capability than other recording devices.

  16. The Galileo Solid-State Imaging experiment

    USGS Publications Warehouse

    Belton, M.J.S.; Klaasen, K.P.; Clary, M.C.; Anderson, J.L.; Anger, C.D.; Carr, M.H.; Chapman, C.R.; Davies, M.E.; Greeley, R.; Anderson, D.; Bolef, L.K.; Townsend, T.E.; Greenberg, R.; Head, J. W.; Neukum, G.; Pilcher, C.B.; Veverka, J.; Gierasch, P.J.; Fanale, F.P.; Ingersoll, A.P.; Masursky, H.; Morrison, D.; Pollack, James B.

    1992-01-01

    The Solid State Imaging (SSI) experiment on the Galileo Orbiter spacecraft utilizes a high-resolution (1500 mm focal length) television camera with an 800 ?? 800 pixel virtual-phase, charge-coupled detector. It is designed to return images of Jupiter and its satellites that are characterized by a combination of sensitivity levels, spatial resolution, geometric fiedelity, and spectral range unmatched by imaging data obtained previously. The spectral range extends from approximately 375 to 1100 nm and only in the near ultra-violet region (??? 350 nm) is the spectral coverage reduced from previous missions. The camera is approximately 100 times more sensitive than those used in the Voyager mission, and, because of the nature of the satellite encounters, will produce images with approximately 100 times the ground resolution (i.e., ??? 50 m lp-1) on the Galilean satellites. We describe aspects of the detector including its sensitivity to energetic particle radiation and how the requirements for a large full-well capacity and long-term stability in operating voltages led to the choice of the virtual phase chip. The F/8.5 camera system can reach point sources of V(mag) ??? 11 with S/N ??? 10 and extended sources with surface brightness as low as 20 kR in its highest gain state and longest exposure mode. We describe the performance of the system as determined by ground calibration and the improvements that have been made to the telescope (same basic catadioptric design that was used in Mariner 10 and the Voyager high-resolution cameras) to reduce the scattered light reaching the detector. The images are linearly digitized 8-bits deep and, after flat-fielding, are cosmetically clean. Information 'preserving' and 'non-preserving' on-board data compression capabilities are outlined. A special "summation" mode, designed for use deep in the Jovian radiation belts, near Io, is also described. The detector is 'preflashed' before each exposure to ensure the photometric linearity

  17. Interaction of epicatechin gallate with phospholipid membranes as revealed by solid-state NMR spectroscopy.

    PubMed

    Uekusa, Yoshinori; Kamihira-Ishijima, Miya; Sugimoto, Osamu; Ishii, Takeshi; Kumazawa, Shigenori; Nakamura, Kozo; Tanji, Ken-ichi; Naito, Akira; Nakayama, Tsutomu

    2011-06-01

    Epicatechin gallate (ECg), a green tea polyphenol, has various physiological effects. Our previous nuclear Overhauser effect spectroscopy (NOESY) study using solution NMR spectroscopy demonstrated that ECg strongly interacts with the surface of phospholipid bilayers. However, the dynamic behavior of ECg in the phospholipid bilayers has not been clarified, especially the dynamics and molecular arrangement of the galloyl moiety, which supposedly has an important interactive role. In this study, we synthesized [13C]-ECg, in which the carbonyl carbon of the galloyl moiety was labeled by 13C isotope, and analyzed it by solid-state NMR spectroscopy. Solid-state 31P NMR analysis indicated that ECg changes the gel-to-liquid-crystalline phase transition temperature of DMPC bilayers as well as the dynamics and mobility of the phospholipids. In the solid-state 13C NMR analysis under static conditions, the carbonyl carbon signal of the [13C]-ECg exhibited an axially symmetric powder pattern. This indicates that the ECg molecules rotate about an axis tilting at a constant angle to the bilayer normal. The accurate intermolecular-interatomic distance between the labeled carbonyl carbon of [13C]-ECg and the phosphorus of the phospholipid was determined to be 5.3±0.1 Å by 13C-(31)P rotational echo double resonance (REDOR) measurements. These results suggest that the galloyl moiety contributes to increasing the hydrophobicity of catechin molecules, and consequently to high affinity of galloyl-type catechins for phospholipid membranes, as well as to stabilization of catechin molecules in the phospholipid membranes by cation-π interaction between the galloyl ring and quaternary amine of the phospholipid head-group. PMID:21352801

  18. In vivo13C spectroscopy in the rat brain using hyperpolarized [1- 13C]pyruvate and [2- 13C]pyruvate

    NASA Astrophysics Data System (ADS)

    Marjańska, Małgorzata; Iltis, Isabelle; Shestov, Alexander A.; Deelchand, Dinesh K.; Nelson, Christopher; Uğurbil, Kâmil; Henry, Pierre-Gilles

    2010-10-01

    The low sensitivity of 13C spectroscopy can be enhanced using dynamic nuclear polarization. Detection of hyperpolarized [1- 13C]pyruvate and its metabolic products has been reported in kidney, liver, and muscle. In this work, the feasibility of measuring 13C signals of hyperpolarized 13C metabolic products in the rat brain in vivo following the injection of hyperpolarized [1- 13C]pyruvate and [2- 13C]pyruvate is investigated. Injection of [2- 13C]pyruvate led to the detection of [2- 13C]lactate, but no other downstream metabolites such as TCA cycle intermediates were detected. Injection of [1- 13C]pyruvate enabled the detection of both [1- 13C]lactate and [ 13C]bicarbonate. A metabolic model was used to fit the hyperpolarized 13C time courses obtained during infusion of [1- 13C]pyruvate and to determine the values of VPDH and VLDH.

  19. Monitoring Cocrystal Formation via In Situ Solid-State NMR.

    PubMed

    Mandala, Venkata S; Loewus, Sarel J; Mehta, Manish A

    2014-10-01

    A detailed understanding of the mechanism of organic cocrystal formation remains elusive. Techniques that interrogate a reacting system in situ are preferred, though experimentally challenging. We report here the results of a solid-state in situ NMR study of the spontaneous formation of a cocrystal between a pharmaceutical mimic (caffeine) and a coformer (malonic acid). Using (13)C magic angle spinning NMR, we show that the formation of the cocrystal may be tracked in real time. We find no direct evidence for a short-lived, chemical shift-resolved amorphous solid intermediate. However, changes in the line width and line center of the malonic acid methylene resonance, in the course of the reaction, provide subtle clues to the mode of mass transfer that underlies cocrystal formation.

  20. High Resolution Imaging Spectrometer (HIRIS)

    NASA Technical Reports Server (NTRS)

    Conley, Joseph M.; Herring, Mark; Norris, David D.

    1988-01-01

    The High Resolution Imaging Spectrometer (HIRIS), related data system, orbit, and mission operations are described. The pushbroom instrument simultaneously images the terrestrial surface in 192 spectral bands from 0.4 to 2.5 microns. The swath width is 30 km and spatial resolution is 30 m. It is planned to be launched with the Earth Observing System aboard the Space Station Polar Platform in 1995. Array detectors allow concurrent integration of the signals at 192,000 detector elements.

  1. Solid-state NMR studies of theophylline co-crystals with dicarboxylic acids.

    PubMed

    Pindelska, Edyta; Sokal, Agnieszka; Szeleszczuk, Lukasz; Pisklak, Dariusz Maciej; Kolodziejski, Waclaw

    2014-11-01

    In this work, three polycrystalline materials containing co-crystals of theophylline with malonic, maleic, and glutaric acids were studied using (13)C, (15)N and (1)H solid-state NMR and FT-IR spectroscopy. The NMR assignments were supported by gauge including projector augmented waves (GIPAW) calculations of chemical shielding, performed using X-ray determined geometry. The experimental (13)C cross polarization/magic angle spinning (CP/MAS) NMR results and the calculated isotropic chemical shifts were in excellent agreement. A rapid and convenient method for theophylline co-crystals crystal structure analysis has been proposed for co-crystals, which are potentially new APIs.

  2. Solid-state diffusion in amorphous zirconolite

    SciTech Connect

    Yang, C.; Dove, M. T.; Trachenko, K.; Zarkadoula, E.; Todorov, I. T.; Geisler, T.; Brazhkin, V. V.

    2014-11-14

    We discuss how structural disorder and amorphization affect solid-state diffusion, and consider zirconolite as a currently important case study. By performing extensive molecular dynamics simulations, we disentangle the effects of amorphization and density, and show that a profound increase of solid-state diffusion takes place as a result of amorphization. Importantly, this can take place at the same density as in the crystal, representing an interesting general insight regarding solid-state diffusion. We find that decreasing the density in the amorphous system increases pre-factors of diffusion constants, but does not change the activation energy in the density range considered. We also find that atomic species in zirconolite are affected differently by amorphization and density change. Our microscopic insights are relevant for understanding how solid-state diffusion changes due to disorder and for building predictive models of operation of materials to be used to encapsulate nuclear waste.

  3. Solid-state diffusion in amorphous zirconolite

    NASA Astrophysics Data System (ADS)

    Yang, C.; Zarkadoula, E.; Dove, M. T.; Todorov, I. T.; Geisler, T.; Brazhkin, V. V.; Trachenko, K.

    2014-11-01

    We discuss how structural disorder and amorphization affect solid-state diffusion, and consider zirconolite as a currently important case study. By performing extensive molecular dynamics simulations, we disentangle the effects of amorphization and density, and show that a profound increase of solid-state diffusion takes place as a result of amorphization. Importantly, this can take place at the same density as in the crystal, representing an interesting general insight regarding solid-state diffusion. We find that decreasing the density in the amorphous system increases pre-factors of diffusion constants, but does not change the activation energy in the density range considered. We also find that atomic species in zirconolite are affected differently by amorphization and density change. Our microscopic insights are relevant for understanding how solid-state diffusion changes due to disorder and for building predictive models of operation of materials to be used to encapsulate nuclear waste.

  4. Standards Development for Solid-State Lighting

    SciTech Connect

    2011-12-16

    To accelerate the development and implementation of needed standards for solid-state lighting products, DOE works closely with a network of standards-setting organizations and offers technical assistance and support

  5. RNA structure determination by solid-state NMR spectroscopy

    PubMed Central

    Marchanka, Alexander; Simon, Bernd; Althoff-Ospelt, Gerhard; Carlomagno, Teresa

    2015-01-01

    Knowledge of the RNA three-dimensional structure, either in isolation or as part of RNP complexes, is fundamental to understand the mechanism of numerous cellular processes. Because of its flexibility, RNA represents a challenge for crystallization, while the large size of cellular complexes brings solution-state NMR to its limits. Here, we demonstrate an alternative approach on the basis of solid-state NMR spectroscopy. We develop a suite of experiments and RNA labeling schemes and demonstrate for the first time that ssNMR can yield a RNA structure at high-resolution. This methodology allows structural analysis of segmentally labelled RNA stretches in high-molecular weight cellular machines—independent of their ability to crystallize— and opens the way to mechanistic studies of currently difficult-to-access RNA-protein assemblies. PMID:25960310

  6. Grating enhanced solid-state laser amplifiers

    SciTech Connect

    Erlandson, Alvin C.; Britten, Jerald A.

    2010-11-09

    A novel method and apparatus for suppressing ASE and parasitic oscillation modes in a high average power laser is introduced. Such an invention, as disclosed herein, uses diffraction gratings to increase gain, stored energy density, and pumping efficiency of solid-state laser gain media, such as, but not limited to rods, disks and slabs. By coupling predetermined gratings to solid-state gain media, such as crystal or ceramic laser gain media, ASE and parasitic oscillation modes can be effectively suppressed.

  7. Transverse mode control in solid state lasers

    SciTech Connect

    Bobeck, A.H.; Harriott, L.R.; Hartman, R.L.; Kaplan, D.R.; Przybylek, G.J.; Tabor, W.J.

    1989-09-26

    This patent describes a solid state laser. It comprises a solid state body including an optical resonator, a waveguide in which laser radiation propagates in TE and TM modes. The radiation being incident on a region of a first surface of the body, characterized by a reflection filter disposed on the first surface so as to preferentially reflect either TE or TM modes and to suppress oscillation within the resonator of the non-reflected modes.

  8. Solution and Solid State Nuclear Magnetic Resonance Spectroscopic Characterization of Efavirenz.

    PubMed

    Sousa, Eduardo Gomes Rodrigues de; Carvalho, Erika Martins de; San Gil, Rosane Aguiar da Silva; Santos, Tereza Cristina Dos; Borré, Leandro Bandeira; Santos-Filho, Osvaldo Andrade; Ellena, Javier

    2016-09-01

    Samples of efavirenz (EFZ) were evaluated to investigate the influence of the micronization process on EFZ stability. A combination of X-ray diffraction, thermal analysis, FTIR, observations of isotropic chemical shifts of (1)H in distinct solvents, their temperature dependence and spin-lattice relaxation time constants (T1), solution (1D and 2D) (13)C nuclear magnetic resonance (NMR), and solid-state (13)C NMR (CPMAS NMR) provides valuable structural information and structural elucidation of micronized EFZ and heptane-recrystallized polymorphs (EFZ/HEPT). This study revealed that the micronization process did not affect the EFZ crystalline structure. It was observed that the structure of EFZ/HEPT is in the same form as that obtained from ethyl acetate/hexane, as shown in the literature. A comparison of the solid-state NMR spectra revealed discrepancies regarding the assignments of some carbons published in the literature that have been resolved.

  9. Effects of cogrinding with β-cyclodextrin on the solid state fentanyl.

    PubMed

    Ogawa, Noriko; Higashi, Kenjirou; Nagase, Hiromasa; Endo, Tomohiro; Moribe, Kunikazu; Loftsson, Thorsteinn; Yamamoto, Keiji; Ueda, Haruhisa

    2010-12-01

    Fentanyl base and β-cyclodextrin (β-CD) were coground at 1:1 and 1:2 molar ratios (fentanyl: β-CD) and the physicochemical characteristics of the mixtures were studied using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), solid state (13)C nuclear magnetic resonance (NMR) spectroscopy and powder X-ray diffraction (PXRD) measurement. Additionally, portions of the coground samples were exposed to high relative humidity to investigate fentanyl and β-CD interactions. The results of DSC and PXRD analyses indicate that the ground mixtures are in an amorphous state, and the FTIR measurements show hydrogen bonding interactions between fentanyl and β-CD. Solid state (13)C NMR indicates that a fentanyl/β-CD inclusion compound is formed in the humidified mixture. Furthermore, PXRD data from the humidified mixtures are similar to the PXRD patterns from the inclusion complex.

  10. Molecular-level secondary structure, polymorphism, and dynamics of full-length alpha-synuclein fibrils studied by solid-state NMR.

    PubMed

    Heise, Henrike; Hoyer, Wolfgang; Becker, Stefan; Andronesi, Ovidiu C; Riedel, Dietmar; Baldus, Marc

    2005-11-01

    The 140-residue protein alpha-synuclein (AS) is able to form amyloid fibrils and as such is the main component of protein inclusions involved in Parkinson's disease. We have investigated the structure and dynamics of full-length AS fibrils by high-resolution solid-state NMR spectroscopy. Homonuclear and heteronuclear 2D and 3D spectra of fibrils grown from uniformly (13)C/(15)N-labeled AS and AS reverse-labeled for two of the most abundant amino acids, K and V, were analyzed. (13)C and (15)N signals exhibited linewidths of <0.7 ppm. Sequential assignments were obtained for 48 residues in the hydrophobic core region. We identified two different types of fibrils displaying chemical-shift differences of up to 13 ppm in the (15)N dimension and up to 5 ppm for backbone and side-chain (13)C chemical shifts. EM studies suggested that molecular structure is correlated with fibril morphology. Investigation of the secondary structure revealed that most amino acids of the core region belong to beta-strands with similar torsion angles in both conformations. Selection of regions with different mobility indicated the existence of monomers in the sample and allowed the identification of mobile segments of the protein within the fibril in the presence of monomeric protein. At least 35 C-terminal residues were mobile and lacked a defined secondary structure, whereas the N terminus was rigid starting from residue 22. Our findings agree well with the overall picture obtained with other methods and provide insight into the amyloid fibril structure and dynamics with residue-specific resolution. PMID:16247008

  11. Parallel β-Sheet Structure of Alanine Tetrapeptide in the Solid State As Studied by Solid-State NMR Spectroscopy.

    PubMed

    Asakura, Tetsuo; Horiguchi, Kumiko; Aoki, Akihiro; Tasei, Yugo; Naito, Akira

    2016-09-01

    The structural analysis of alanine oligopeptides is important for understanding the crystalline region in silks from spiders and wild silkworms and also the mechanism of cellular toxicity of human diseases arising from expansion in polyalanine sequences. The atomic-level structures of alanine tripeptide and tetrapeptide with antiparallel β-sheet structures (AP-Ala3 and AP-Ala4, respectively) together with alanine tripeptide with parallel β-sheet structures (P-Ala3) have been determined, but alanine tetrapeptide with a parallel β-sheet structure (P-Ala4) has not been reported yet. In this article, first, we established the preparation protocol of P-Ala4 from more stable AP-Ala4. Second, complete assignments of the (13)C, (15)N, and (1)H solid-state NMR spectra were performed with (13)C- and (15)N-labeled Ala4 samples using several solid-state NMR techniques. Then, the structural constraints were obtained, for example, the amide proton peaks of P-Ala4 in the (1)H double-quantum magic-angle spinning NMR spectrum were heavily overlapped and observed at about 7.4 ppm, which was a much higher field than that of 8.7-9.1 ppm observed for AP-Ala4, indicating that the intermolecular hydrogen-bond lengths across strands (N-H···O═C) were considerably longer for P-Ala4, that is, 2.21-2.34 Å, than those reported for AP-Ala4, that is, 1.8-1.9 Å. The structural model was proposed for P-Ala4 by NMR results and MD calculations. PMID:27482868

  12. Precise quantum control on solid-state spins

    NASA Astrophysics Data System (ADS)

    Geng, Jianpei

    Precise quantum control is of great importance for quantum information processing, high resolution spectroscopy, and quantum metrology. One of the key obstacles to realizing precise quantum control on solid-state spins is the noises arising from both environment and control field. Here, we design a composite pulse to realize precise quantum control on a single electron spin in diamond by suppressing the effect of both noises simultaneously. The control is experimentally demonstrated to be with a low error rate of 4.8E-5. We improve quantum optimal control method to realize precise two-qubit quantum control on a system comprised by a single electron spin and 14N nuclear spin. With the improved quantum optimal control method, we design a pulse sequence for CNOT gate to suppress the noises simultaneously. The error rate of CNOT gate is measured to be 8E-3. To the best of our knowledge, the control we have realized stands for the state of art in precise quantum control on solid-state spins.

  13. High Resolution Global View of Io

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Io, the most volcanic body in the solar system is seen in the highest resolution obtained to date by NASA's Galileo spacecraft. The smallest features that can be discerned are 2.5 kilometers in size. There are rugged mountains several kilometers high, layered materials forming plateaus, and many irregular depressions called volcanic calderas. Several of the dark, flow-like features correspond to hot spots, and may be active lava flows. There are no landforms resembling impact craters, as the volcanism covers the surface with new deposits much more rapidly than the flux of comets and asteroids can create large impact craters. The picture is centered on the side of Io that always faces away from Jupiter; north is to the top.

    Color images acquired on September 7, 1996 have been merged with higher resolution images acquired on November 6, 1996 by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft. The color is composed of data taken, at a range of 487,000 kilometers, in the near-infrared, green, and violet filters and has been enhanced to emphasize the extraordinary variations in color and brightness that characterize Io's face. The high resolution images were obtained at ranges which varied from 245,719 kilometers to 403,100 kilometers.

    Launched in October 1989, Galileo entered orbit around Jupiter on December 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  14. Solid-state characterization of two polymorphs of aspartame hemihydrate.

    PubMed

    Leung, S S; Padden, B E; Munson, E J; Grant, D J

    1998-04-01

    From the known crystal structure of aspartame hemihydrate, designated form 1, the theoretical powder X-ray diffraction (PXRD) pattern was calculated. This PXRD pattern differs significantly from that of the commercially available aspartame hemihydrate, which is therefore a different polymorph, designated form II. Form II transforms to form I during ball-milling or on heating for 30 min at 160 degrees C in the presence of steam. The two polymorphs were compared by PXRD, differential scanning calorimetry, thermogravimetric analysis, Karl Fischer titrimetry, Fourier transform infrared (FTIR) absorption spectroscopy, 13C solid-state nuclear magnetic resonance (SSNMR) spectroscopy, scanning electron microscopy, particle size analysis, and measurements of true density and intrinsic dissolution rate. Comparison of the 13C SSNMR and FTIR spectra of the two polymorphs suggests that the crystal structure of form II is less symmetric, with the side chains located in multiple environments. Although both hemihydrate polymorphs on heating in the absence of moisture dehydrate to a crystalline anhydrate, form I does so at a lower temperature, suggesting weaker interactions of water with aspartame molecules. At higher temperatures the anhydrate from both hemihydrate polymorphs yields 3-(carboxymethyl)-6-benzyl-2,5-dioxopiperazine (DKP) by a cyclization reaction for which the temperature, reaction enthalpy, and activation energy are very similar. Both hemihydrate forms, when in contact with liquid water, yield the 2.5-hydrate.

  15. A new method of imaging particle tracks in solid state nuclear track detectors.

    PubMed

    Wertheim, D; Gillmore, G; Brown, L; Petford, N

    2010-01-01

    Solid state nuclear track detectors are used to determine the concentration of alpha particles in the environment. The standard method for assessing exposed detectors involves 2D image analysis. However 3D imaging has the potential to provide additional information relating to angle as well as to differentiate clustered hit sequences and possibly energy of alpha particles but this could be time consuming. Here we describe a new method for rapid high-resolution 3D imaging of solid state nuclear track detectors. A 'LEXT' OLS3100 confocal laser scanning microscope (Olympus Corporation, Tokyo, Japan) was used in confocal mode to successfully obtain 3D image data on four CR-39 plastic detectors. Three-dimensional visualization and image analysis enabled characterization of track features. This method may provide a means of rapid and detailed 3D analysis of solid state nuclear track detectors.

  16. DARPA high resolution display technologies

    NASA Astrophysics Data System (ADS)

    Slusarczuk, Marko

    1990-11-01

    Much of the information of interest to pilots in flight is display-limited, and is undergoing substantial expansion due to improved sensor output and signal processing; attention is accordingly given to digitally-based instrument display imaging in the present evaluation of high-resolution cockpit display technologies. Also noted are the advantages of digitally transmitted sensor data in cases where the airborne reconnaissance user may be able to analyze telemetered airborne data in real time and respond with requests to the pilot for more detailed information of specific battlefield sites.

  17. High-Resolution Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Dozier, Jeff; Goetz, Alexander F. H.

    1990-01-01

    Earth resources observed in greater detail. High-Resolution Imaging Spectrometer, undergoing development for use in NASA's Earth Observing System, measures reflectance of Earth's surface in visible and near-infrared wavelengths. From an orbit around Earth, instrument scans surface of Earth in 200 wavelength bands simultaneously. Produces images enabling identification of minerals in rocks and soils, important algal pigments in oceans and inland waters, changes in spectra associated with biochemistry of plant canopies, compositions of atmospheric aerosols, sizes of grains in snow, and contamination of snow by impurities that absorb visible light.

  18. High Resolution Scanning Reflectarray Antenna

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R. (Inventor); Miranda, Felix A. (Inventor)

    2000-01-01

    The present invention provides a High Resolution Scanning Reflectarray Antenna (HRSRA) for the purpose of tracking ground terminals and space craft communication applications. The present invention provides an alternative to using gimbaled parabolic dish antennas and direct radiating phased arrays. When compared to a gimbaled parabolic dish, the HRSRA offers the advantages of vibration free steering without incurring appreciable cost or prime power penalties. In addition, it offers full beam steering at a fraction of the cost of direct radiating arrays and is more efficient.

  19. Chemical structure and heterogeneity differences of two lignins from loblolly pine as investigated by advanced solid-state NMR spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Advanced solid-state NMR was employed to investigate differences in chemical structure and heterogeneity between milled wood lignin (MWL) and residual enzyme lignin (REL). Wiley and conventional milled woods were also studied. The advanced NMR techniques included 13C quantitative direct polarization...

  20. Solid-state continuous Lyman-alpha source for laser-cooling of antihydrogen

    SciTech Connect

    Walz, Jochen; Beyer, Thomas; Kolbe, Daniel; Markert, Frank; Muellers, Andreas; Scheid, Martin

    2008-08-08

    Cooling antihydrogen atoms is important for future experiments both to test the fundamental CPT symmetry by high-resolution laser spectroscopy and also to measure the gravitational acceleration of antimatter. Laser-cooling of antihydrogen can be done on the strong 1 S-2 P transition at the wavelength of Lyman-alpha (121.6 nm). Ongoing work to set up a solid-state continuous-wave laser source at Lyman-alpha is described.

  1. Structural analysis of geochemical samples by solid-state nuclear magnetic resonance spectrometry. Role of paramagnetic material

    USGS Publications Warehouse

    Vassallo, A.M.; Wilson, M.A.; Collin, P.J.; Oades, J.M.; Waters, A.G.; Malcolm, R.L.

    1987-01-01

    An examination of coals, coal tars, a fulvic acid, and soil fractions by solid-state 13C NMR spectrometry has demonstrated widely differing behavior regarding quantitative representation in the spectrum. Spin counting experiments on coal tars and the fulvic acid show that almost all the sample carbon is observed in both solution and solid-state NMR spectra. Similar experiments on two coals (a lignite and a bituminous coal) show that most (70-97%) of the carbon is observed; however, when the lignite is ion exchanged with 3% (w/w) Fe3+, the fraction of carbon observed drops to below 10%. In additional experiments signal intensity from soil samples is enhanced by a simple dithionite treatment. This is illustrated by 13C, 27Al, and 29Si solid-state NMR experiments on soil fractions. ?? 1987 American Chemical Society.

  2. Millimeter and submillimeter wave spectra of 13C-glycolaldehydes

    NASA Astrophysics Data System (ADS)

    Haykal, I.; Motiyenko, R. A.; Margulès, L.; Huet, T. R.

    2013-01-01

    Context. Glycolaldehyde (CH2OHCHO) is the simplest sugar and an important intermediate in the path toward forming more complex biologically relevant molecules. Astronomical surveys of interstellar molecules, such as those available with the very sensitive ALMA telescope, require preliminary laboratory investigations of the microwave and submillimeter-wave spectra of molecular species including new isotopologs - to identify these in the interstellar media. Aims: To achieve the detection of the 13C isotopologs of glycolaldehyde in the interstellar medium, their rotational spectra in the millimeter and submillimeter-wave regions were studied. Methods: The spectra of 13CH2OHCHO and CH2OH13CHO were recorded in the 150-945 GHz spectral range in the laboratory using a solid-state submillimeter-wave spectrometer in Lille. The observed line frequencies were measured with an accuracy of 30 kHz up to 700 GHz and of 50 kHz above 700 GHz. We analyzed the spectra with a standard Watson Hamiltonian. Results: About 10 000 new lines were identified for each isotopolog. The spectroscopic parameters were determined for the ground- and the three lowest vibrational states up to 945 and 630 GHz. Previous microwave assignments of 13CH2OHCHO were not confirmed. Conclusions: The provided line-lists and sets of molecular parameters meet the needs for a first astrophysical search of 13C-glycolaldehydes. Full Tables 3 and 4 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/549/A96

  3. Modular nonvolatile solid state recorder (MONSSTR) update

    NASA Astrophysics Data System (ADS)

    Klang, Mark R.; Small, Martin B.; Beams, Tom

    2001-12-01

    Solid state recorders have begun replacing traditional tape recorders in fulfilling the requirement to record images on airborne platforms. With the advances in electro-optical, IR, SAR, Multi and Hyper-spectral sensors and video recording requirements, solid state recorders have become the recorder of choice. Solid state recorders provide the additional storage, higher sustained bandwidth, less power, less weight and smaller footprint to meet the current and future recording requirements. CALCULEX, Inc., manufactures a non-volatile flash memory solid state recorder called the MONSSTR (Modular Non-volatile Solid State Recorder). MONSSTR is being used to record images from many different digital sensors on high performance aircraft such as the RF- 4, F-16 and the Royal Air Force Tornado. MONSSTR, with its internal multiplexer, is also used to record instrumentation data. This includes multiple streams of PCM and multiple channels of 1553 data. Instrumentation data is being recorded by MONSSTR systems in a range of platforms including F-22, F-15, F-16, Comanche Helicopter and US Navy torpedos. MONSSTR can also be used as a cockpit video recorder. This paper will provide an update of the MONSSTR.

  4. Feasibility of Multianimal Hyperpolarized 13C MRS

    PubMed Central

    Ramirez, Marc S.; Lee, Jaehyuk; Walker, Christopher M.; Chen, Yunyun; Kingsley, Charles V.; De La Cerda, Jorge; Maldonado, Kiersten L.; Lai, Stephen Y.; Bankson, James A.

    2014-01-01

    Purpose There is great potential for real-time investigation of metabolism with MRS and hyperpolarized (HP) 13C agents. Unfortunately, HP technology has high associated costs and efficiency limitations that may constrain in vivo studies involving many animals. To improve the throughput of preclinical investigations, we evaluate the feasibility of performing HP MRS on multiple animals simultaneously. Methods Simulations helped assess the viability of a dual-coil strategy for spatially-localized multivolume MRS.A dual-mouse system was assembled and characterized based on bench- and scanner-based experiments. Enzyme phantoms mixed with HP [1-13C] pyruvate emulated real-time metabolism and offered a controlled mechanism for evaluating system performance. Finally, a normal mouse and a mouse bearing a subcutaneous xenograft of colon cancer were simultaneously scanned in vivo using an agent containing HP [1-13C] pyruvate. Results Geometric separation/rotation, active decoupling, and use of low input impedance preamplifiers permitted an encode-by-channel approach for spatially-localized MRS. A pre-calibrated shim allowed straightforward metabolite differentiation in enzyme phantom and in vivo experiments at 7 T, with performance similar to conventional acquisitions. Conclusion The initial feasibility of multi-animal HP 13C MRS was established. Throughput scales with the number of simultaneously-scanned animals, demonstrating the potential for significant improvements in study efficiency. PMID:24903532

  5. Investigations of adsorption sites on oxide surfaces using solid-state NMR and TPD-IGC

    NASA Astrophysics Data System (ADS)

    Golombeck, Rebecca A.

    diameters and thermal histories. The bulk structural features in both compositions of glass fibers were identified using high-resolution 29Si, 27Al, and 11B magic-angle spinning (MAS) NMR spectroscopic measurements. In multi-component glasses, the determination of silicon, aluminum, and boron distributions becomes difficult due to the competitive nature of the network-modifying oxides among the network-forming oxides. In pure silicates, 29Si MAS NMR can often resolve resonances arising from silicate tetrahedron having varying numbers of bridging oxygens. In aluminoborosilicate glasses, aluminum is present in four-, five-, and six- coordination with oxygen as neighbors. The speciation of the aluminum can be determined using 27Al MAS NMR. The fraction of tetrahedral boron species in the glass fibers were measured using 11B MAS NMR, which is typically used to study the short-range structure of borate containing glasses such as alkali borate, borosilicate, and aluminoborosilicate glasses. While solid-state NMR is a powerful tool for elucidating bonding environments and coordination changes in the glass structure, it cannot quantitatively probe low to moderate surface area samples due to insufficient spins. Chemical probes either physisorbed or chemisorbed to the fiber's surface can increase the surface selectivity of NMR for analysis of samples with low surface areas and provide information about the local molecular structure of the reactive surface site. Common chemical probe molecules contain NMR active nuclei such as 19F or may be enriched with 13C. A silyating agent, (3,3,3-trifluoropropyl)dimethylchlorosilane (TFS), reacts with reactive surface hydroxyls, which can be quantified by utilizing the NMR active nucleus (19F) contained in the probe molecule. The observed 19F MAS NMR peak area is integrated and compared against a standard of known fluorine spins (concentration), allowing the number of reactive hydroxyl sites to be quantified. IGC is a method used to study the

  6. Driver circuit for solid state light sources

    DOEpatents

    Palmer, Fred; Denvir, Kerry; Allen, Steven

    2016-02-16

    A driver circuit for a light source including one or more solid state light sources, a luminaire including the same, and a method of so driving the solid state light sources are provided. The driver circuit includes a rectifier circuit that receives an alternating current (AC) input voltage and provides a rectified AC voltage. The driver circuit also includes a switching converter circuit coupled to the light source. The switching converter circuit provides a direct current (DC) output to the light source in response to the rectified AC voltage. The driver circuit also includes a mixing circuit, coupled to the light source, to switch current through at least one solid state light source of the light source in response to each of a plurality of consecutive half-waves of the rectified AC voltage.

  7. Solid state recording current meter conversion

    USGS Publications Warehouse

    Cheng, Ralph T.; Wang, Lichen

    1985-01-01

    The authors describe the conversion of an Endeco-174 current meter to a solid-state recording current meter. A removable solid-state module was designed to fit in the space originally occupied by an 8-track tape cartridge. The module contains a CPU and 128 kilobytes of nonvolatile CMOS memory. The solid-state module communicates with any terminal or computer using an RS-232C interface at 4800 baud rate. A primary consideration for conversion was to keep modifications of the current meter to a minimum. The communication protocol was designed to emulate the Endeco tape translation unit, thus the need for a translation unit was eliminated and the original data reduction programs can be used without any modification. After conversion, the data recording section of the current meter contains no moving parts; the storage capacity of the module is equivalent to that of the original tape cartridge.

  8. Monolayer to interdigitated partial bilayer smectic C transition in thiophene-based spacer mesogens: X-ray diffraction and (13)C nuclear magnetic resonance studies.

    PubMed

    Kesava Reddy, M; Varathan, E; Lobo, Nitin P; Roy, Arun; Narasimhaswamy, T; Ramanathan, K V

    2015-10-01

    Mesophase organization of molecules built with thiophene at the center and linked via flexible spacers to rigid side arm core units and terminal alkoxy chains has been investigated. Thirty homologues realized by varying the span of the spacers as well as the length of the terminal chains have been studied. In addition to the enantiotropic nematic phase observed for all the mesogens, the increase of the spacer as well as the terminal chain lengths resulted in the smectic C phase. The molecular organization in the smectic phase as investigated by temperature dependent X-ray diffraction measurements revealed an interesting behavior that depended on the length of the spacer vis-a-vis the length of the terminal chain. Thus, a tilted interdigitated partial bilayer organization was observed for molecules with a shorter spacer length, while a tilted monolayer arrangement was observed for those with a longer spacer length. High-resolution solid state (13)C NMR studies carried out for representative mesogens indicated a U-shape for all the molecules, indicating that intermolecular interactions and molecular dynamics rather than molecular shape are responsible for the observed behavior. Models for the mesophase organization have been considered and the results understood in terms of segregation of incompatible parts of the mesogens combined with steric frustration leading to the observed lamellar order.

  9. Solid State Lasers from an Efficiency Perspective

    NASA Technical Reports Server (NTRS)

    Barnes, Norman P.

    2007-01-01

    Solid state lasers have remained a vibrant area of research because several major innovations expanded their capability. Major innovations are presented with emphasis focused on the laser efficiency. A product of efficiencies approach is developed and applied to describe laser performance. Efficiency factors are presented in closed form where practical and energy transfer effects are included where needed. In turn, efficiency factors are used to estimate threshold and slope efficiency, allowing a facile estimate of performance. Spectroscopic, thermal, and mechanical data are provided for common solid state laser materials.

  10. Recent Results of Solid-State Spectroscopy

    NASA Astrophysics Data System (ADS)

    Jäger, Cornelia; Posch, Thomas; Mutschke, Harald; Zeidler, Simon; Tamanai, Akemi; de Vries, Bernard L.

    2011-12-01

    Solid state spectroscopy continues to be an important source of information on the mineralogical composition and physical properties of dust grains both in space and on planetary surfaces. With only a few exceptions, artificially produced or natural terrestrial analog materials, rather than `real' cosmic dust grains, are the subject of solid state astrophysics. The Jena laboratory has provided a large number of data sets characterizing the UV, optical and infrared properties of such cosmic dust analogs. The present paper highlights recent developments and results achieved in this context, focussing on `non-standard conditions' such as very low temperatures, very high temperatures and very long wavelengths.

  11. High Resolution Thermography In Medicine

    NASA Astrophysics Data System (ADS)

    Clark, R. P.; Goff, M. R.; Culley, J. E.

    1988-10-01

    A high resolution medical thermal imaging system using an 8 element SPRI1E detector is described. Image processing is by an Intellect 100 processor and is controlled by a DEC LSI 11/23 minicomputer. Image storage is with a 170 Mbyte winchester disc together with archival storage on 12 inch diameter optical discs having a capacity of 1 Gbyte per side. The system is currently being evaluated for use in physiology and medicine. Applications outlined include the potential of thermographic screening to identify genetic carriers in X-linked hypohidrotic ectodermal dysplasia (XED), detailed vas-cular perfusion studies in health and disease and the relation-ship between cutaneous blood flow, neurological peripheral function and skin surface temperature.

  12. Enhanced High Resolution RBS System

    NASA Astrophysics Data System (ADS)

    Pollock, Thomas J.; Hass, James A.; Klody, George M.

    2011-06-01

    Improvements in full spectrum resolution with the second NEC high resolution RBS system are summarized. Results for 50 Å TiN/HfO films on Si yielding energy resolution on the order of 1 keV are also presented. Detector enhancements include improved pulse processing electronics, upgraded shielding for the MCP/RAE detector, and reduced noise generated from pumping. Energy resolution measurements on spectra front edge coupled with calculations using 0.4mStr solid angle show that beam energy spread at 400 KeV from the Pelletron® accelerator is less than 100 eV. To improve user throughput, magnet control has been added to the automatic data collection. Depth profiles derived from experimental data are discussed. For the thin films profiled, depth resolutions were on the Angstrom level with the non-linear energy/channel conversions ranging from 100 to 200 eV.

  13. High Resolution Neutral Atom Microscope

    NASA Astrophysics Data System (ADS)

    Bucay, Igal; Castillo-Garza, Rodrigo; Stratis, Georgios; Raizen, Mark

    2015-03-01

    We are developing a high resolution neutral atom microscope based on metastable atom electron spectroscopy (MAES). When a metastable atom of a noble gas is near a solid, a surface electron will tunnel to an empty energy level of the metastable atom, thereby ejecting the excited electron from the atom. The emitted electrons carry information regarding the local topography and electronic, magnetic, and chemical structures of most hard materials. Furthermore, using a chromatic aberration corrected magnetic hexapole lens we expect to attain a spatial resolution below 10 nm. We will use this microscope to investigate how local phenomena can give rise to macroscopic effects in materials that cannot be probed using a scanning tunneling microscope, namely insulating transition metal oxides.

  14. High resolution spectrograph. [for LST

    NASA Technical Reports Server (NTRS)

    Peacock, K.

    1975-01-01

    The high resolution spectrograph (HRS) is designed to be used with the Large Space Telescope (LST) for the study of spectra of point and extended targets in the spectral range 110 to 410 nm. It has spectral resolutions of 1,000; 30,000; and 100,000 and has a field of view as large as 10 arc sec. The spectral range and resolution are selectable using interchangeable optical components and an echelle spectrograph is used to display a cross dispersed spectrum on the photocathode of either of 2 SEC orthicon image tubes. Provisions are included for wavelength calibration, target identification and acquisition and thermal control. The system considerations of the instrument are described.

  15. High-resolution imaging ellipsometer.

    PubMed

    Zhan, Qiwen; Leger, James R

    2002-08-01

    We report on a novel imaging ellipsometer using a high-numerical-aperture (NA) objective lens capable of measuring a two-dimensional ellipsometric signal with high resolution. Two-dimensional ellipsometric imaging is made possible by spatial filtering at the pupil plane of the objective. A Richards-Wolf vectorial diffraction model and geometrical optics model are developed to simulate the system. The thickness profile of patterned polymethyl methacrylate is measured for calibration purposes. Our instrument has a sensitivity of 5 A and provides spatial resolution of approximately 0.5 microm with 632.8-nm illumination. Its capability of measuring refractive-index variations with high spatial resolution is also demonstrated.

  16. A high resolution TDC subsystem

    SciTech Connect

    Geiges, R.; Merle, K. )

    1994-02-01

    A high resolution TDC subsystem was developed at the Institute for Nuclear Physics in Mainz. The TDC chip offers a time resolution of less than 300 ps and a programmable measurement range from 0 to 16 [mu]sec. The time measurement is done with a new, purely digital counting method. The chip can be operated in common start or common stop mode. In common start mode the chip is able to store up to 4 multiple hits per channel. The chip is used to build a transputer controlled subsystem for the measurement of the drift times of a vertical drift chamber. The design of the subsystem will be described and the first results from the tests of the prototype system will be presented.

  17. High resolution tomographic instrument development

    SciTech Connect

    Not Available

    1992-08-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  18. High resolution tomographic instrument development

    SciTech Connect

    Not Available

    1992-01-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  19. High resolution tomographic instrument development

    NASA Astrophysics Data System (ADS)

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefitted greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  20. Mars high-resolution mapping

    NASA Astrophysics Data System (ADS)

    Batson, R. M.; Thomas, P. K.

    1991-06-01

    A series of photomosaics of high-resolution Viking Orbiter images of Mars is being prepared and published to support the Mars 1:500,000 scale geologic mapping program. More than 100 of these photomosaics were made manually, but for the last several years they have all been made digitally. The digital mosaics are published on the Mars Transverse Mercator (MTM) system, and they are also available to the appropriate principal investigators as digital files in the mosaicked digital image model (MDIM) format. The mosaics contain Viking Orbiter images with the highest available resolution: in some areas as high as 10 m/pixel. This resolution, where it exists, will support a 1:100,000 map scale. The full resolution of a mosaic is preserved in a digital file, but conventional lithographic publication of such large-scale inset maps will be done only if required by the geologic map author. When high-resolution images do not fill the neat lines of an MTM quadrangle, the medium-resolution (1/256 degrees/pixel, or 231 m/pixel) MDIM is used. The mosaics are tied by image-matching to the planetwide MDIM, in which random errors as large as 5 km (10 mm at 1:500,000 scale) are common; a few much larger, worst-case errors also occur. Because of the distribution of the errors, many large discrepancies appear along the cutlines between frames with very different resolutions. Furthermore, each block of quadrangles is compiled on its own local control system, and adjacent blocks, compiled later, are unlikely to match. Selection of areas to be mapped is based on geologic mapping proposals reviewed and recommended by the Mars 1:500,000 scale geologic mapping review panel. There is no intention to map the entire planet at this scale.

  1. HRSC: High resolution stereo camera

    USGS Publications Warehouse

    Neukum, G.; Jaumann, R.; Basilevsky, A.T.; Dumke, A.; Van Gasselt, S.; Giese, B.; Hauber, E.; Head, J. W.; Heipke, C.; Hoekzema, N.; Hoffmann, H.; Greeley, R.; Gwinner, K.; Kirk, R.; Markiewicz, W.; McCord, T.B.; Michael, G.; Muller, Jan-Peter; Murray, J.B.; Oberst, J.; Pinet, P.; Pischel, R.; Roatsch, T.; Scholten, F.; Willner, K.

    2009-01-01

    The High Resolution Stereo Camera (HRSC) on Mars Express has delivered a wealth of image data, amounting to over 2.5 TB from the start of the mapping phase in January 2004 to September 2008. In that time, more than a third of Mars was covered at a resolution of 10-20 m/pixel in stereo and colour. After five years in orbit, HRSC is still in excellent shape, and it could continue to operate for many more years. HRSC has proven its ability to close the gap between the low-resolution Viking image data and the high-resolution Mars Orbiter Camera images, leading to a global picture of the geological evolution of Mars that is now much clearer than ever before. Derived highest-resolution terrain model data have closed major gaps and provided an unprecedented insight into the shape of the surface, which is paramount not only for surface analysis and geological interpretation, but also for combination with and analysis of data from other instruments, as well as in planning for future missions. This chapter presents the scientific output from data analysis and highlevel data processing, complemented by a summary of how the experiment is conducted by the HRSC team members working in geoscience, atmospheric science, photogrammetry and spectrophotometry. Many of these contributions have been or will be published in peer-reviewed journals and special issues. They form a cross-section of the scientific output, either by summarising the new geoscientific picture of Mars provided by HRSC or by detailing some of the topics of data analysis concerning photogrammetry, cartography and spectral data analysis.

  2. Synthesis Of [2h, 13c] And [2h3, 13c]Methyl Aryl Sulfides

    DOEpatents

    Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.

    2004-03-30

    The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2,.sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms. The present invention is also directed to the labeled compounds of [.sup.2 H.sub.1, .sup.13 C]methyl iodide and [.sup.2 H.sub.2, .sup.13 C]methyl iodide.

  3. Solid state NMR: The essential technology for helical membrane protein structural characterization

    NASA Astrophysics Data System (ADS)

    Cross, Timothy A.; Ekanayake, Vindana; Paulino, Joana; Wright, Anna

    2014-02-01

    NMR spectroscopy of helical membrane proteins has been very challenging on multiple fronts. The expression and purification of these proteins while maintaining functionality has consumed countless graduate student hours. Sample preparations have depended on whether solution or solid-state NMR spectroscopy was to be performed - neither have been easy. In recent years it has become increasingly apparent that membrane mimic environments influence the structural result. Indeed, in these recent years we have rediscovered that Nobel laureate, Christian Anfinsen, did not say that protein structure was exclusively dictated by the amino acid sequence, but rather by the sequence in a given environment (Anfinsen, 1973) [106]. The environment matters, molecular interactions with the membrane environment are significant and many examples of distorted, non-native membrane protein structures have recently been documented in the literature. However, solid-state NMR structures of helical membrane proteins in proteoliposomes and bilayers are proving to be native structures that permit a high resolution characterization of their functional states. Indeed, solid-state NMR is uniquely able to characterize helical membrane protein structures in lipid environments without detergents. Recent progress in expression, purification, reconstitution, sample preparation and in the solid-state NMR spectroscopy of both oriented samples and magic angle spinning samples has demonstrated that helical membrane protein structures can be achieved in a timely fashion. Indeed, this is a spectacular opportunity for the NMR community to have a major impact on biomedical research through the solid-state NMR spectroscopy of these proteins.

  4. Solid state NMR: The essential technology for helical membrane protein structural characterization.

    PubMed

    Cross, Timothy A; Ekanayake, Vindana; Paulino, Joana; Wright, Anna

    2014-02-01

    NMR spectroscopy of helical membrane proteins has been very challenging on multiple fronts. The expression and purification of these proteins while maintaining functionality has consumed countless graduate student hours. Sample preparations have depended on whether solution or solid-state NMR spectroscopy was to be performed - neither have been easy. In recent years it has become increasingly apparent that membrane mimic environments influence the structural result. Indeed, in these recent years we have rediscovered that Nobel laureate, Christian Anfinsen, did not say that protein structure was exclusively dictated by the amino acid sequence, but rather by the sequence in a given environment (Anfinsen, 1973) [106]. The environment matters, molecular interactions with the membrane environment are significant and many examples of distorted, non-native membrane protein structures have recently been documented in the literature. However, solid-state NMR structures of helical membrane proteins in proteoliposomes and bilayers are proving to be native structures that permit a high resolution characterization of their functional states. Indeed, solid-state NMR is uniquely able to characterize helical membrane protein structures in lipid environments without detergents. Recent progress in expression, purification, reconstitution, sample preparation and in the solid-state NMR spectroscopy of both oriented samples and magic angle spinning samples has demonstrated that helical membrane protein structures can be achieved in a timely fashion. Indeed, this is a spectacular opportunity for the NMR community to have a major impact on biomedical research through the solid-state NMR spectroscopy of these proteins.

  5. Conformational isomerism in solid state of AMG 853--structure studies using solid-state nuclear magnetic resonance and X-ray diffraction.

    PubMed

    Kiang, Y-H; Nagapudi, Karthik; Wu, Tian; Peterson, Matthew L; Jona, Janan; Staples, Richard J; Stephens, Peter W

    2015-07-01

    Investigation of an additional resonance peak in the (19) F solid-state nuclear magnetic resonance (NMR) spectrum of AMG 853, a dual antagonist of DP and CRTH2 previously in clinical development for asthma, has led to the identification of two conformational isomers coexisting in the crystal lattice in a continuous composition range between 89.7%:10.3% and 96.5%:3.5%. These two isomers differ in the chloro-flurorophenyl moiety orientation-the aromatic ring is flipped by 180° in these two isomers. The level of the minor isomer is directly measured through integration of the two peaks in the (19) F solid-state NMR spectrum. The values obtained from the NMR data are in excellent agreement with the degree of disorder of the fluorine atom in the crystal structure, refined using both single-crystal and high-resolution powder X-ray diffraction data.

  6. RF-controlled implantable solid state switch

    NASA Technical Reports Server (NTRS)

    Fryer, T. B.

    1971-01-01

    Miniature, totally implantable, solid state RF-controlled switching circuit for biotelemetry systems consumes zero power in off condition and turns on or off by pulse of RF energy. Switch, the size of small coin, is reducible by integrated circuit techniques.

  7. Solid-state NMR imaging system

    SciTech Connect

    Gopalsami, N.; Dieckman, S.L.; Ellingson, W.A.

    1990-01-01

    An accessory for use with a solid-state NMR spectrometer includes a special imaging probe with linear, high-field strength gradient fields and high-power broadband RF coils using a back projection method for data acquisition and image reconstruction, and a real-time pulse programmer adaptable for use by a conventional computer for complex high speed pulse sequences.

  8. Nanoscale solid-state cooling: a review.

    PubMed

    Ziabari, Amirkoushyar; Zebarjadi, Mona; Vashaee, Daryoosh; Shakouri, Ali

    2016-09-01

    The recent developments in nanoscale solid-state cooling are reviewed. This includes both theoretical and experimental studies of different physical concepts, as well as nanostructured material design and device configurations. We primarily focus on thermoelectric, thermionic and thermo-magnetic coolers. Particular emphasis is given to the concepts based on metal-semiconductor superlattices, graded materials, non-equilibrium thermoelectric devices, Thomson coolers, and photon assisted Peltier coolers as promising methods for efficient solid-state cooling. Thermomagnetic effects such as magneto-Peltier and Nernst-Ettingshausen cooling are briefly described and recent advances and future trends in these areas are reviewed. The ongoing progress in solid-state cooling concepts such as spin-calorimetrics, electrocalorics, non-equilibrium/nonlinear Peltier devices, superconducting junctions and two-dimensional materials are also elucidated and practical achievements are reviewed. We explain the thermoreflectance thermal imaging microscopy and the transient Harman method as two unique techniques developed for characterization of thermoelectric microrefrigerators. The future prospects for solid-state cooling are briefly summarized. PMID:27519021

  9. The Pythagorean Theorem and the Solid State

    ERIC Educational Resources Information Center

    Kelly, Brenda S.; Splittgerber, Allan G.

    2005-01-01

    Packing efficiency and crystal density can be calculated from basic geometric principles employing the Pythagorean theorem, if the unit-cell structure is known. The procedures illustrated have applicability in courses such as general chemistry, intermediate and advanced inorganic, materials science, and solid-state physics.

  10. Nanoscale solid-state cooling: a review.

    PubMed

    Ziabari, Amirkoushyar; Zebarjadi, Mona; Vashaee, Daryoosh; Shakouri, Ali

    2016-09-01

    The recent developments in nanoscale solid-state cooling are reviewed. This includes both theoretical and experimental studies of different physical concepts, as well as nanostructured material design and device configurations. We primarily focus on thermoelectric, thermionic and thermo-magnetic coolers. Particular emphasis is given to the concepts based on metal-semiconductor superlattices, graded materials, non-equilibrium thermoelectric devices, Thomson coolers, and photon assisted Peltier coolers as promising methods for efficient solid-state cooling. Thermomagnetic effects such as magneto-Peltier and Nernst-Ettingshausen cooling are briefly described and recent advances and future trends in these areas are reviewed. The ongoing progress in solid-state cooling concepts such as spin-calorimetrics, electrocalorics, non-equilibrium/nonlinear Peltier devices, superconducting junctions and two-dimensional materials are also elucidated and practical achievements are reviewed. We explain the thermoreflectance thermal imaging microscopy and the transient Harman method as two unique techniques developed for characterization of thermoelectric microrefrigerators. The future prospects for solid-state cooling are briefly summarized.

  11. Nanoscale solid-state cooling: a review

    NASA Astrophysics Data System (ADS)

    Ziabari, Amirkoushyar; Zebarjadi, Mona; Vashaee, Daryoosh; Shakouri, Ali

    2016-09-01

    The recent developments in nanoscale solid-state cooling are reviewed. This includes both theoretical and experimental studies of different physical concepts, as well as nanostructured material design and device configurations. We primarily focus on thermoelectric, thermionic and thermo-magnetic coolers. Particular emphasis is given to the concepts based on metal-semiconductor superlattices, graded materials, non-equilibrium thermoelectric devices, Thomson coolers, and photon assisted Peltier coolers as promising methods for efficient solid-state cooling. Thermomagnetic effects such as magneto-Peltier and Nernst-Ettingshausen cooling are briefly described and recent advances and future trends in these areas are reviewed. The ongoing progress in solid-state cooling concepts such as spin-calorimetrics, electrocalorics, non-equilibrium/nonlinear Peltier devices, superconducting junctions and two-dimensional materials are also elucidated and practical achievements are reviewed. We explain the thermoreflectance thermal imaging microscopy and the transient Harman method as two unique techniques developed for characterization of thermoelectric microrefrigerators. The future prospects for solid-state cooling are briefly summarized.

  12. Solid state lasers - The next 10 years

    NASA Astrophysics Data System (ADS)

    Byer, Robert L.

    1988-10-01

    Major advances in solid state laser technology historically have been preceded by advances in pumping technology. The helical lamp used to pump the early ruby lasers was superseded by the linear flashlamp now used to pump Nd:YAG lasers. The next advance in pumping technology is the diode laser array. The improvements in power and efficiency of the diode laser coupled with the fortuitous spectral overlap of the diode laser emission wavelength with the Nd ion absorption bands near 805 nm have led to a revolution in solid state laser capability. Progress has been rapid with new ions and wavelengths reported in the near infrared from 946 nm to 2010 nm. Frequency extension via nonlinear interactions has led to green and blue sources of coherent radiation. Linewidths of less than 10 kHz have been demonstrated. Overall electrical efficiencies of greater than 10% have been achieved. As diode laser sources decrease in cost, high average power diode laser pumped solid state laser sources will become available. Power levels exceeding 1 kW appear possible. Potential applications of these compact all solid state laser sources to spectroscopy, quantum noise limited sensors, astronomy, and materials processing will be discussed.

  13. Density functional theory in the solid state

    PubMed Central

    Hasnip, Philip J.; Refson, Keith; Probert, Matt I. J.; Yates, Jonathan R.; Clark, Stewart J.; Pickard, Chris J.

    2014-01-01

    Density functional theory (DFT) has been used in many fields of the physical sciences, but none so successfully as in the solid state. From its origins in condensed matter physics, it has expanded into materials science, high-pressure physics and mineralogy, solid-state chemistry and more, powering entire computational subdisciplines. Modern DFT simulation codes can calculate a vast range of structural, chemical, optical, spectroscopic, elastic, vibrational and thermodynamic phenomena. The ability to predict structure–property relationships has revolutionized experimental fields, such as vibrational and solid-state NMR spectroscopy, where it is the primary method to analyse and interpret experimental spectra. In semiconductor physics, great progress has been made in the electronic structure of bulk and defect states despite the severe challenges presented by the description of excited states. Studies are no longer restricted to known crystallographic structures. DFT is increasingly used as an exploratory tool for materials discovery and computational experiments, culminating in ex nihilo crystal structure prediction, which addresses the long-standing difficult problem of how to predict crystal structure polymorphs from nothing but a specified chemical composition. We present an overview of the capabilities of solid-state DFT simulations in all of these topics, illustrated with recent examples using the CASTEP computer program. PMID:24516184

  14. Density functional theory in the solid state.

    PubMed

    Hasnip, Philip J; Refson, Keith; Probert, Matt I J; Yates, Jonathan R; Clark, Stewart J; Pickard, Chris J

    2014-03-13

    Density functional theory (DFT) has been used in many fields of the physical sciences, but none so successfully as in the solid state. From its origins in condensed matter physics, it has expanded into materials science, high-pressure physics and mineralogy, solid-state chemistry and more, powering entire computational subdisciplines. Modern DFT simulation codes can calculate a vast range of structural, chemical, optical, spectroscopic, elastic, vibrational and thermodynamic phenomena. The ability to predict structure-property relationships has revolutionized experimental fields, such as vibrational and solid-state NMR spectroscopy, where it is the primary method to analyse and interpret experimental spectra. In semiconductor physics, great progress has been made in the electronic structure of bulk and defect states despite the severe challenges presented by the description of excited states. Studies are no longer restricted to known crystallographic structures. DFT is increasingly used as an exploratory tool for materials discovery and computational experiments, culminating in ex nihilo crystal structure prediction, which addresses the long-standing difficult problem of how to predict crystal structure polymorphs from nothing but a specified chemical composition. We present an overview of the capabilities of solid-state DFT simulations in all of these topics, illustrated with recent examples using the CASTEP computer program.

  15. Solar-pumped solid state Nd lasers

    NASA Technical Reports Server (NTRS)

    Williams, M. D.; Zapata, L.

    1985-01-01

    Solid state neodymium lasers are considered candidates for space-based polar-pumped laser for continuous power transmission. Laser performance for three different slab laser configurations has been computed to show the excellent power capability of such systems if heat problems can be solved. Ideas involving geometries and materials are offered as potential solutions to the heat problem.

  16. Nanoscale solid-state cooling: a review

    NASA Astrophysics Data System (ADS)

    Ziabari, Amirkoushyar; Zebarjadi, Mona; Vashaee, Daryoosh; Shakouri, Ali

    2016-09-01

    The recent developments in nanoscale solid-state cooling are reviewed. This includes both theoretical and experimental studies of different physical concepts, as well as nanostructured material design and device configurations. We primarily focus on thermoelectric, thermionic and thermo-magnetic coolers. Particular emphasis is given to the concepts based on metal–semiconductor superlattices, graded materials, non-equilibrium thermoelectric devices, Thomson coolers, and photon assisted Peltier coolers as promising methods for efficient solid-state cooling. Thermomagnetic effects such as magneto–Peltier and Nernst–Ettingshausen cooling are briefly described and recent advances and future trends in these areas are reviewed. The ongoing progress in solid-state cooling concepts such as spin-calorimetrics, electrocalorics, non-equilibrium/nonlinear Peltier devices, superconducting junctions and two-dimensional materials are also elucidated and practical achievements are reviewed. We explain the thermoreflectance thermal imaging microscopy and the transient Harman method as two unique techniques developed for characterization of thermoelectric microrefrigerators. The future prospects for solid-state cooling are briefly summarized.

  17. SPS solid state antenna power combiner

    NASA Technical Reports Server (NTRS)

    Fitzsimmons, G. W.

    1980-01-01

    Solid state dc-rf converters offer potential improvements in reliability, mass and low voltage operation, provided that anticipated efficiencies in excess of 80 percent can be realized. Field effect transistors offer the greatest potential in the SPS frequency band at 2.45 GHz. To implement this approach it is essential that means be found to sum the power of many relatively low power solid state sources in a low-loss manner, and that means be provided to properly control the phase of the outputs of the large number of solid state sources required. To avoid the power combining losses associated with circuit hybrids it was proposed that the power from multiple solid state amplifiers be combined by direct coupling of each amplifier's output to the radiating antenna structure. The selected power-combining antenna consists of a unique printed (metalized) microstrip circuit on a ceramic type dielectric substrate which is backed by a shallow lightweight aluminum cavity which sums the power of four microwave sources. The antenna behaves like two one-half wavelength slot-line antennas coupled together via their common cavity structure.

  18. {sup 13}C-{sup 1}H and {sup 13}C-{sup 13}C spin couplings in [2`-{sup 13}C]2`-deoxyribonucleosides: Correlations with molecular structure

    SciTech Connect

    Bandyopadhyay, T.; Stripe, W.A.; Carmichael, I.; Serianni, A.S.; Wu, J.

    1997-02-19

    2`-Deoxyribonucleosides (2`-deoxyadenosine (1), 2`-depoxycytidine (2), thymidine (3)) singly enriched with {sup 13}C at C2` have been prepared and used to obtain one-, two-, and three-bond {sup 13}C-{sup 1}H and {sup 13}C-{sup 13}C spin-coupling constants involving C2`. Spin couplings in 1-3 involving C1` and C2`are also compared to corresponding values in ribonucleosides in order to assess the effects of nucleoside structure and conformation on J values within the furanose ring. {sup 1}J{sub C2`,H2`R} and {sup 1}J{sub C2`,H2`S} in 1-3 and {sup 1}J{sub C2`,H2`} in ribonucleosides depend on C-H bond orientation: {sup 1}J{sub C1`,H1`} in 1-3 and in ribonucleosides exhibits a similar dependence. The latter couplings appear to be essentially unaffected by N-glycoside torsion. {sup 1}J{sub CC} values depend on the number and distribution of electronegative substituents on the C-C fragment. A modified projection curve is proposed to aid in the interpretation of {sup 2}J{sub C2`,H1`} values; the presence of N substitution at C1` caused a shift to more negative couplings relative to the O-substituted analog. In contrast, {sup 2}J{sub C1`,H2`} is essentially unaffected by the same change in the electronegative substituent at C1`. {sup 2}J{sub CC} values within the furanose ring are determined buy two coupling pathways; in one case (i.e., {sup 2}J{sub C1`,C3`}), the observed coupling is shown to be the algebraic sum of the two couplings arising from each pathway. 41 refs., 4 figs., 2 tabs.

  19. A 13C NMR study of the structure of four cinnamic acids and their methyl esters

    NASA Astrophysics Data System (ADS)

    Silva, A. M. S.; Alkorta, I.; Elguero, J.; Silva, V. L. M.

    2001-09-01

    The 13C NMR spectra, both in DMSO solution and in the solid state of four cinnamic acids ( p-methoxy, p-hydroxy, p-methyl, p-chloro) and their corresponding methyl esters have been recorded. The two main results in the solid state are: (i) the only significant difference between acids and esters chemical shifts concerns the CO group which, on average, appears at 173 ppm in the acids and 168 ppm in the esters; (ii) the signals of the ortho and meta carbons both in the acids and the esters are splitted. The two 'anomalies' disappear in DMSO solution. These observations can be rationalized using simple GIAO/B3LYP/6-31G ∗ calculations.

  20. Proton-detected 2D radio frequency driven recoupling solid-state NMR studies on micelle-associated cytochrome-b5

    NASA Astrophysics Data System (ADS)

    Pandey, Manoj Kumar; Vivekanandan, Subramanian; Yamamoto, Kazutoshi; Im, Sangchoul; Waskell, Lucy; Ramamoorthy, Ayyalusamy

    2014-05-01

    Solid-state NMR spectroscopy is increasingly used in the high-resolution structural studies of membrane-associated proteins and peptides. Most such studies necessitate isotopically labeled (13C, 15N and 2H) proteins/peptides, which is a limiting factor for some of the exciting membrane-bound proteins and aggregating peptides. In this study, we report the use of a proton-based slow magic angle spinning (MAS) solid-state NMR experiment that exploits the unaveraged 1H-1H dipolar couplings from a membrane-bound protein. We have shown that the difference in the buildup rates of cross-peak intensities against the mixing time - obtained from 2D 1H-1H radio frequency-driven recoupling (RFDR) and nuclear Overhauser effect spectroscopy (NOESY) experiments on a 16.7-kDa micelle-associated full-length rabbit cytochrome-b5 (cytb5) - can provide insights into protein dynamics and could be useful to measure 1H-1H dipolar couplings. The experimental buildup curves compare well with theoretical simulations and are used to extract relaxation parameters. Our results show that due to fast exchange of amide protons with water in the soluble heme-containing domain of cyb5, coherent 1H-1H dipolar interactions are averaged out for these protons while alpha and side chain protons show residual dipolar couplings that can be obtained from 1H-1H RFDR experiments. The appearance of resonances with distinct chemical shift values in 1H-1H RFDR spectra enabled the identification of residues (mostly from the transmembrane region) of cytb5 that interact with micelles.

  1. Coordinated garbage collection for raid array of solid state disks

    SciTech Connect

    Dillow, David A; Ki, Youngjae; Oral, Hakki S; Shipman, Galen M; Wang, Feiyi

    2014-04-29

    An optimized redundant array of solid state devices may include an array of one or more optimized solid-state devices and a controller coupled to the solid-state devices for managing the solid-state devices. The controller may be configured to globally coordinate the garbage collection activities of each of said optimized solid-state devices, for instance, to minimize the degraded performance time and increase the optimal performance time of the entire array of devices.

  2. High resolution time interval counter

    DOEpatents

    Condreva, Kenneth J.

    1994-01-01

    A high resolution counter circuit measures the time interval between the occurrence of an initial and a subsequent electrical pulse to two nanoseconds resolution using an eight megahertz clock. The circuit includes a main counter for receiving electrical pulses and generating a binary word--a measure of the number of eight megahertz clock pulses occurring between the signals. A pair of first and second pulse stretchers receive the signal and generate a pair of output signals whose widths are approximately sixty-four times the time between the receipt of the signals by the respective pulse stretchers and the receipt by the respective pulse stretchers of a second subsequent clock pulse. Output signals are thereafter supplied to a pair of start and stop counters operable to generate a pair of binary output words representative of the measure of the width of the pulses to a resolution of two nanoseconds. Errors associated with the pulse stretchers are corrected by providing calibration data to both stretcher circuits, and recording start and stop counter values. Stretched initial and subsequent signals are combined with autocalibration data and supplied to an arithmetic logic unit to determine the time interval in nanoseconds between the pair of electrical pulses being measured.

  3. High resolution time interval counter

    DOEpatents

    Condreva, K.J.

    1994-07-26

    A high resolution counter circuit measures the time interval between the occurrence of an initial and a subsequent electrical pulse to two nanoseconds resolution using an eight megahertz clock. The circuit includes a main counter for receiving electrical pulses and generating a binary word--a measure of the number of eight megahertz clock pulses occurring between the signals. A pair of first and second pulse stretchers receive the signal and generate a pair of output signals whose widths are approximately sixty-four times the time between the receipt of the signals by the respective pulse stretchers and the receipt by the respective pulse stretchers of a second subsequent clock pulse. Output signals are thereafter supplied to a pair of start and stop counters operable to generate a pair of binary output words representative of the measure of the width of the pulses to a resolution of two nanoseconds. Errors associated with the pulse stretchers are corrected by providing calibration data to both stretcher circuits, and recording start and stop counter values. Stretched initial and subsequent signals are combined with autocalibration data and supplied to an arithmetic logic unit to determine the time interval in nanoseconds between the pair of electrical pulses being measured. 3 figs.

  4. High resolution optoelectronic retinal prosthesis

    NASA Astrophysics Data System (ADS)

    Loudin, Jim; Dinyari, Rostam; Huie, Phil; Butterwick, Alex; Peumans, Peter; Palanker, Daniel

    2009-02-01

    Electronic retinal prostheses seek to restore sight in patients with retinal degeneration by delivering pulsed electric currents to retinal neurons via an array of microelectrodes. Most implants use inductive or optical transmission of information and power to an intraocular receiver, with decoded signals subsequently distributed to retinal electrodes through an intraocular cable. Surgical complexity could be minimized by an "integrated" prosthesis, in which both power and data are delivered directly to the stimulating array without any discrete components or cables. We present here an integrated retinal prosthesis system based on a photodiode array implant. Video frames are processed and imaged onto the retinal implant by a video goggle projection system operating at near-infrared wavelengths (~ 900 nm). Photodiodes convert light into pulsed electric current, with charge injection maximized by specially optimized series photodiode circuits. Prostheses of three different pixel densities (16 pix/mm2, 64 pix/mm2, and 256 pix/mm2) have been designed, simulated, and prototyped. Retinal tissue response to subretinal implants made of various materials has been investigated in RCS rats. The resulting prosthesis can provide sufficient charge injection for high resolution retinal stimulation without the need for implantation of any bulky discrete elements such as coils or tethers. In addition, since every pixel functions independently, pixel arrays may be placed separately in the subretinal space, providing visual stimulation to a larger field of view.

  5. High resolution imaging at Palomar

    NASA Technical Reports Server (NTRS)

    Kulkarni, Shrinivas R.

    1992-01-01

    For the last two years we have embarked on a program of understanding the ultimate limits of ground-based optical imaging. We have designed and fabricated a camera specifically for high resolution imaging. This camera has now been pressed into service at the prime focus of the Hale 5 m telescope. We have concentrated on two techniques: the Non-Redundant Masking (NRM) and Weigelt's Fully Filled Aperture (FFA) method. The former is the optical analog of radio interferometry and the latter is a higher order extension of the Labeyrie autocorrelation method. As in radio Very Long Baseline Interferometry (VLBI), both these techniques essentially measure the closure phase and, hence, true image construction is possible. We have successfully imaged binary stars and asteroids with angular resolution approaching the diffraction limit of the telescope and image quality approaching that of a typical radio VLBI map. In addition, we have carried out analytical and simulation studies to determine the ultimate limits of ground-based optical imaging, the limits of space-based interferometric imaging, and investigated the details of imaging tradeoffs of beam combination in optical interferometers.

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

    PubMed Central

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

    2013-01-01

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

  7. Quantification of peptide m/z distributions from 13C-labeled cultures with high resolution mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the introduction of orbital trap mass spectrometers molecular masses can be determined with great precision and accuracy. In addition, orbital trap spectrometers (Orbitraps) are sensitive and possess a linear dynamic range of multiple orders of magnitude. These qualities make the Orbitrap well-...

  8. On The Potential of Dynamic Nuclear Polarization Enhanced Diamonds in Solid-State and Dissolution (13) C NMR Spectroscopy.

    PubMed

    Bretschneider, Christian O; Akbey, Ümit; Aussenac, Fabien; Olsen, Greg L; Feintuch, Akiva; Oschkinat, Hartmut; Frydman, Lucio

    2016-09-01

    Dynamic nuclear polarization (DNP) is a versatile option to improve the sensitivity of NMR and MRI. This versatility has elicited interest for overcoming potential limitations of these techniques, including the achievement of solid-state polarization enhancement at ambient conditions, and the maximization of (13) C signal lifetimes for performing in vivo MRI scans. This study explores whether diamond's (13) C behavior in nano- and micro-particles could be used to achieve these ends. The characteristics of diamond's DNP enhancement were analyzed for different magnetic fields, grain sizes, and sample environments ranging from cryogenic to ambient temperatures, in both solution and solid-state experiments. It was found that (13) C NMR signals could be boosted by orders of magnitude in either low- or room-temperature solid-state DNP experiments by utilizing naturally occurring paramagnetic P1 substitutional nitrogen defects. We attribute this behavior to the unusually long electronic/nuclear spin-lattice relaxation times characteristic of diamond, coupled with a time-independent cross-effect-like polarization transfer mechanism facilitated by a matching of the nitrogen-related hyperfine coupling and the (13) C Zeeman splitting. The efficiency of this solid-state polarization process, however, is harder to exploit in dissolution DNP-enhanced MRI contexts. The prospects for utilizing polarized diamond approaching nanoscale dimensions for both solid and solution applications are briefly discussed. PMID:27416769

  9. On The Potential of Dynamic Nuclear Polarization Enhanced Diamonds in Solid-State and Dissolution (13) C NMR Spectroscopy.

    PubMed

    Bretschneider, Christian O; Akbey, Ümit; Aussenac, Fabien; Olsen, Greg L; Feintuch, Akiva; Oschkinat, Hartmut; Frydman, Lucio

    2016-09-01

    Dynamic nuclear polarization (DNP) is a versatile option to improve the sensitivity of NMR and MRI. This versatility has elicited interest for overcoming potential limitations of these techniques, including the achievement of solid-state polarization enhancement at ambient conditions, and the maximization of (13) C signal lifetimes for performing in vivo MRI scans. This study explores whether diamond's (13) C behavior in nano- and micro-particles could be used to achieve these ends. The characteristics of diamond's DNP enhancement were analyzed for different magnetic fields, grain sizes, and sample environments ranging from cryogenic to ambient temperatures, in both solution and solid-state experiments. It was found that (13) C NMR signals could be boosted by orders of magnitude in either low- or room-temperature solid-state DNP experiments by utilizing naturally occurring paramagnetic P1 substitutional nitrogen defects. We attribute this behavior to the unusually long electronic/nuclear spin-lattice relaxation times characteristic of diamond, coupled with a time-independent cross-effect-like polarization transfer mechanism facilitated by a matching of the nitrogen-related hyperfine coupling and the (13) C Zeeman splitting. The efficiency of this solid-state polarization process, however, is harder to exploit in dissolution DNP-enhanced MRI contexts. The prospects for utilizing polarized diamond approaching nanoscale dimensions for both solid and solution applications are briefly discussed.

  10. Atomic resolution protein structure determination by three-dimensional transferred echo double resonance solid-state nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Nieuwkoop, Andrew J.; Wylie, Benjamin J.; Franks, W. Trent; Shah, Gautam J.; Rienstra, Chad M.

    2009-09-01

    We show that quantitative internuclear N15-C13 distances can be obtained in sufficient quantity to determine a complete, high-resolution structure of a moderately sized protein by magic-angle spinning solid-state NMR spectroscopy. The three-dimensional ZF-TEDOR pulse sequence is employed in combination with sparse labeling of C13 sites in the β1 domain of the immunoglobulin binding protein G (GB1), as obtained by bacterial expression with 1,3-C13 or 2-C13-glycerol as the C13 source. Quantitative dipolar trajectories are extracted from two-dimensional N15-C13 planes, in which ˜750 cross peaks are resolved. The experimental data are fit to exact theoretical trajectories for spin clusters (consisting of one C13 and several N15 each), yielding quantitative precision as good as 0.1 Å for ˜350 sites, better than 0.3 Å for another 150, and ˜1.0 Å for 150 distances in the range of 5-8 Å. Along with isotropic chemical shift-based (TALOS) dihedral angle restraints, the distance restraints are incorporated into simulated annealing calculations to yield a highly precise structure (backbone RMSD of 0.25±0.09 Å), which also demonstrates excellent agreement with the most closely related crystal structure of GB1 (2QMT, bbRMSD 0.79±0.03 Å). Moreover, side chain heavy atoms are well restrained (0.76±0.06 Å total heavy atom RMSD). These results demonstrate for the first time that quantitative internuclear distances can be measured throughout an entire solid protein to yield an atomic-resolution structure.

  11. High resolution absorption spectrum of dianilino in the vapor phase.

    PubMed

    Bayrakçeken, Fuat

    2009-01-01

    Photophysical and photochemical properties of diradical in the first excited state is recorded for the very first time with the IR, band structure for dianilino molecule at room temperature, in the vapor phase. In this experiment high resolution absorption spectra of anilino free radical, dianilino, aniline in the vapor phase and silicon dioxide in the solid state were recorded by flash photolysis technique photographically. Silicon dioxide absorption band between 250 and 255 nm were also observed for the reaction cell, because the cell and windows of the cell material were spectrosilica grade fused quartz. And this absorption band also used as wavelength calibration for all the photoproducts formed in the reaction cell during optical pumping.

  12. III-Nitride full-scale high-resolution microdisplays

    NASA Astrophysics Data System (ADS)

    Day, Jacob; Li, J.; Lie, D. Y. C.; Bradford, Charles; Lin, J. Y.; Jiang, H. X.

    2011-07-01

    We report the realization and properties of a high-resolution solid-state self-emissive microdisplay based on III-nitride semiconductor micro-size light emitting diodes (µLEDs) capable of delivering video graphics images. The luminance level of III-nitride microdisplays is several orders of magnitude higher than those of liquid crystal and organic-LED displays. The pixel emission intensity was almost constant over an operational temperature range from 100 to -100 °C. The outstanding performance is a direct attribute of III-nitride semiconductors. An energy efficient active drive scheme is accomplished by hybrid integration between µLED arrays and Si CMOS (complementary metal-oxide-semiconductor) active matrix integrated circuits. These integrated devices could play important roles in emerging fields such as biophotonics and optogenetics, as well as ultra-portable products such as next generation pico-projectors.

  13. Evaluation of Advanced Bionics high resolution mode.

    PubMed

    Buechner, Andreas; Frohne-Buechner, Carolin; Gaertner, Lutz; Lesinski-Schiedat, Anke; Battmer, Rolf-Dieter; Lenarz, Thomas

    2006-07-01

    The objective of this paper is to evaluate the advantages of the Advanced Bionic high resolution mode for speech perception, through a retrospective analysis. Forty-five adult subjects were selected who had a minimum experience of three months' standard mode (mean of 10 months) before switching to high resolution mode. Speech perception was tested in standard mode immediately before fitting with high resolution mode, and again after a maximum of six months high resolution mode usage (mean of two months). A significant improvement was found, between 11 and 17%, depending on the test material. The standard mode preference does not give any indication about the improvement when switching to high resolution. Users who are converted within any study achieve a higher performance improvement than those converted in the clinical routine. This analysis proves the significant benefits of high resolution mode for users, and also indicates the need for guidelines for individual optimization of parameter settings in a high resolution mode program.

  14. Protein structure determination with paramagnetic solid-state NMR spectroscopy.

    PubMed

    Sengupta, Ishita; Nadaud, Philippe S; Jaroniec, Christopher P

    2013-09-17

    Many structures of the proteins and protein assemblies that play central roles in fundamental biological processes and disease pathogenesis are not readily accessible via the conventional techniques of single-crystal X-ray diffraction and solution-state nuclear magnetic resonance (NMR). On the other hand, many of these challenging biological systems are suitable targets for atomic-level structural and dynamic analysis by magic-angle spinning (MAS) solid-state NMR spectroscopy, a technique that has far less stringent limitations on the molecular size and crystalline state. Over the past decade, major advances in instrumentation and methodology have prompted rapid growth in the field of biological solid-state NMR. However, despite this progress, one challenge for the elucidation of three-dimensional (3D) protein structures via conventional MAS NMR methods is the relative lack of long-distance data. Specifically, extracting unambiguous interatomic distance restraints larger than ∼5 Å from through-space magnetic dipole-dipole couplings among the protein (1)H, (13)C, and (15)N nuclei has proven to be a considerable challenge for researchers. It is possible to circumvent this problem by extending the structural studies to include several analogs of the protein of interest, intentionally modified to contain covalently attached paramagnetic tags at selected sites. In these paramagnetic proteins, the hyperfine couplings between the nuclei and unpaired electrons can manifest themselves in NMR spectra in the form of relaxation enhancements of the nuclear spins that depend on the electron-nucleus distance. These effects can be significant for nuclei located up to ∼20 Å away from the paramagnetic center. In this Account, we discuss MAS NMR structural studies of nitroxide and EDTA-Cu(2+) labeled variants of a model 56 amino acid globular protein, B1 immunoglobulin-binding domain of protein G (GB1), in the microcrystalline solid phase. We used a set of six EDTA-Cu(2

  15. Transient states in [2 + 2] photodimerization of cinnamic acid: correlation of solid-state NMR and X-ray analysis.

    PubMed

    Khan, Mujeeb; Brunklaus, Gunther; Enkelmann, Volker; Spiess, Hans-Wolfgang

    2008-02-01

    13C-CPMAS and other solid-state NMR methods have been applied to monitor the solid-state reactions of trans-cinnamic acid derivatives, which are the pioneer and model compounds in the field of topochemistry previously studied by X-ray diffraction, AFM, and vibrational spectroscopy. Single-crystal X-ray analyses of photoirradiated alpha-trans-cinnamic acid where the monomers are arranged in a head-to-tail manner have revealed the formation of a centrosymmetric alpha-truxillic acid photodimer. For a centrosymmetric dimer, however, two cyclobutane carbon signals and one carbonyl carbon signal were expected apart from other aromatic carbon signals. Instead, four cyclobutane and two carbonyl carbon signals were observed suggesting the formation of a non-centrosymmetric photodimer. Removing hydrogen bonds from the system by esterfication of alpha-truxillic acid yield a centrosymmetric photodimer. Careful analysis of the obtained products via solid-state NMR clearly showed that the observed peak splittings in the 13C-CPMAS spectra did not originate from packing effects but rather result from asymmetric hydrogen bonds distorting the local symmetry. Further evidence of this rather dynamic hydrogen-bonding stems from high-temperature X-ray data revealing that only the joint approach of both X-ray analysis and solid-state NMR at similar temperatures allows for the successful characterization of dynamic processes occurring in topochemical reactions, thus, providing detailed insight into the reaction mechanism of organic solid-state transformations.

  16. High-resolution slug testing.

    PubMed

    Zemansky, G M; McElwee, C D

    2005-01-01

    The hydraulic conductivity (K) variation has important ramifications for ground water flow and the transport of contaminants in ground water. The delineation of the nature of that variation can be critical to complete characterization of a site and the planning of effective and efficient remedial measures. Site-specific features (such as high-conductivity zones) need to be quantified. Our alluvial field site in the Kansas River valley exhibits spatial variability, very high conductivities, and nonlinear behavior for slug tests in the sand and gravel aquifer. High-resolution, multilevel slug tests have been performed in a number of wells that are fully screened. A general nonlinear model based on the Navier-Stokes equation, nonlinear frictional loss, non-Darcian flow, acceleration effects, radius changes in the wellbore, and a Hvorslev model for the aquifer has been used to analyze the data, employing an automated processing system that runs within the Excel spreadsheet program. It is concluded that slug tests can provide the necessary data to identify the nature of both horizontal and vertical K variation in an aquifer and that improved delineation or higher resolution of K structure is possible with shorter test intervals. The gradation into zones of higher conductivity is sharper than seen previously, and the maximum conductivity observed is greater than previously measured. However, data from this project indicate that well development, the presence of fines, and the antecedent history of the well are important interrelated factors in regard to slug-test response and can prevent obtaining consistent results in some cases.

  17. Solid-State NMR Studies Reveal Native-like β-Sheet Structures in Transthyretin Amyloid.

    PubMed

    Lim, Kwang Hun; Dasari, Anvesh K R; Hung, Ivan; Gan, Zhehong; Kelly, Jeffery W; Wright, Peter E; Wemmer, David E

    2016-09-20

    Structural characterization of amyloid rich in cross-β structures is crucial for unraveling the molecular basis of protein misfolding and amyloid formation associated with a wide range of human disorders. Elucidation of the β-sheet structure in noncrystalline amyloid has, however, remained an enormous challenge. Here we report structural analyses of the β-sheet structure in a full-length transthyretin amyloid using solid-state NMR spectroscopy. Magic-angle-spinning (MAS) solid-state NMR was employed to investigate native-like β-sheet structures in the amyloid state using selective labeling schemes for more efficient solid-state NMR studies. Analyses of extensive long-range (13)C-(13)C correlation MAS spectra obtained with selectively (13)CO- and (13)Cα-labeled TTR reveal that the two main β-structures in the native state, the CBEF and DAGH β-sheets, remain intact after amyloid formation. The tertiary structural information would be of great use for examining the quaternary structure of TTR amyloid. PMID:27589034

  18. Solid-state NMR characterization of Mowry Formation shales

    SciTech Connect

    Miknis, F.P.

    1992-04-01

    Solid-state {sup 13}C and {sup 29}Si NMR measurements were carried out on a series of petroleum source rocks from the Mowry Formation of the Powder River Basin in Wyoming. The objectives of this study wereto use CP/MAS {sup 13}C NMR measurements to monitor changes in the carbon structure of the kerogen that result from depth of burial, and to examine the feasibility of {sup 29}Si NMR for studying the thermal alteration of clay minerals during diagenesis. Carbon and silicon NMR measurements were made on a suite of samples covering a present-day depth interval of 3,000 to 11,500 ft.In general, the NMR results endorsed other geochemical analyses that were performed on the source rocks as part of another study to examine pressure compartmentalization in the Mowry Formation. The carbon aromaticity of the kerogen increased with depth of burial, and at depths greater that approximately 10,000 ft the kerogen showed little capacity to generate additional oil because of the small fraction of residual aliphatic carbon. By combining NMR and Rock-Eval measurements, an estimate of the hydrogen budget was obtained. The calculations indicated that approximately 20% of the kerogen was converted to hydrocarbons, and that sufficient hydrogen was liberated from aromatization and condensation reactions to stabilize the generated products. The {sup 29}Si NMR spectra were characterized by a relatively sharp quartz resonance and a broad resonance from the clay minerals. With increasing depth of burial, the clay resonance became broader and shifted slightly downfield. These changes qualitatively support X-ray analysis that shows progressive alteration of illite to smectite with depth of burial.

  19. Solid-state NMR characterization of Mowry Formation shales

    SciTech Connect

    Miknis, F.P.

    1992-04-01

    Solid-state [sup 13]C and [sup 29]Si NMR measurements were carried out on a series of petroleum source rocks from the Mowry Formation of the Powder River Basin in Wyoming. The objectives of this study wereto use CP/MAS [sup 13]C NMR measurements to monitor changes in the carbon structure of the kerogen that result from depth of burial, and to examine the feasibility of [sup 29]Si NMR for studying the thermal alteration of clay minerals during diagenesis. Carbon and silicon NMR measurements were made on a suite of samples covering a present-day depth interval of 3,000 to 11,500 ft.In general, the NMR results endorsed other geochemical analyses that were performed on the source rocks as part of another study to examine pressure compartmentalization in the Mowry Formation. The carbon aromaticity of the kerogen increased with depth of burial, and at depths greater that approximately 10,000 ft the kerogen showed little capacity to generate additional oil because of the small fraction of residual aliphatic carbon. By combining NMR and Rock-Eval measurements, an estimate of the hydrogen budget was obtained. The calculations indicated that approximately 20% of the kerogen was converted to hydrocarbons, and that sufficient hydrogen was liberated from aromatization and condensation reactions to stabilize the generated products. The [sup 29]Si NMR spectra were characterized by a relatively sharp quartz resonance and a broad resonance from the clay minerals. With increasing depth of burial, the clay resonance became broader and shifted slightly downfield. These changes qualitatively support X-ray analysis that shows progressive alteration of illite to smectite with depth of burial.

  20. Phenyl galactopyranosides - 13C CPMAS NMR and conformational analysis using genetic algorithm

    NASA Astrophysics Data System (ADS)

    Wałejko, Piotr; Paradowska, Katarzyna; Bukowicki, Jarosław; Witkowski, Stanisław; Wawer, Iwona

    2015-08-01

    Structural analyses of four compounds (phenyl 2,3,4,6-tetra-O-acetyl-β-D-galactopyranoside (1), phenyl β-D-galactopyranoside (2), phenyl 2,3,4,6-tetra-O-acetyl-α-D-galactopyranoside (3) and phenyl α-D-galactopyranoside (4)) have been performed using solid-state 13C MAS NMR spectroscopy and theoretical methods. Conformational analysis involved grid search and genetic algorithm (GAAGS). Low-energy conformers found by GAAGS were further optimized by DFT and chemical shifts were calculated using GIAO/DFT approach. 13C CPMAS NMR chemical shift of carbon C2 is indicative of the glycoside torsional angle. Separated or merged resonances of C2 and C6 suggest free rotation of phenyl ring in the solid phase.

  1. C-H and C-C clumping in ethane by high-resolution mass spectrometry

    NASA Astrophysics Data System (ADS)

    Clog, M. D.; Eiler, J. M.

    2014-12-01

    Ethane (C2H6) is an important natural compound, and its geochemistry can be studied through 13C-13C, 13C-D and/or D-D clumping. Such measurements are potentially important both as a stepping stone towards the study of more complex organic molecules and, in its own regard, to understand processes controlling the generation, migration and destruction of natural gas. Isotopic clumping on C-C and C-H bonds could be influenced by thermodynamics, chemical kinetics, diffusion or gas mixing. Previous work showed that 13C-D clumping in methane generally reflects equilibrium and provides a measure of formation temperature (Stolper et al 2014a), whereas 13C-13C clumping in ethane is likely most controlled by chemical-kinetic processes and/or inheritance from the isotopic structure of source organic compounds (Clog et al 2014). 13C-D clumping in ethane has the potential to provide a thermometer for its synthesis, as it does for methane. However, the difference in C-H bond dissociation energy for these two compounds may suggest a lower 'blocking temperature' for this phenomenon in ethane (the blocking temperature for methane is ≥~250 C in geological conditions). We present analytical techniques to measure both 13C-13C and 13C-D clumping in ethane, using a novel two-instrument technique, including both the Thermo 253-Ultra and the Thermo DFS. In this method, the Ultra is used to measure the relative abundances of combinations nearly isobaric isotopologues: (13C12CH6 + 12C2DH5)/12C2H6 and (13C2H6 + 12C13CDH5)/12C2H6, free of other isobaric interferences like O2. The DFS, a very high resolution single-collector instrument, is then used to measure the ratios of isotopologues of ethane at a single cardinal mass: 12C2DH5/13C12CH6, and 12C13CDH5/13C2H6, with precisions of ~1 permil. Those 4 measurements allow us to calculate the bulk isotopic composition (D and 13C) as well as the abundance of 13C2H6 and 13C12CDH5. We also present progress on the development of software tools

  2. Broadband spectrally dynamic solid state illumination source

    NASA Astrophysics Data System (ADS)

    Nicol, David B.; Asghar, Ali; Gupta, Shalini; Kang, Hun; Pan, Ming; Strassburg, Martin; Summers, Chris; Ferguson, Ian T.

    2006-06-01

    Solid state lighting has done well recently in niche markets such as signage and displays, however, no available SSL technologies incorporate all the necessary attributes for general illumination. Development of a novel solid state general illumination source is discussed here. Two LEDs emitting at two distinct wavelengths can be monolithically grown and used to excite two or more phosphors with varied excitation spectra. The combined phosphorescence spectrum can then be controlled by adjusting the relative intensities of the two LED emissions. Preliminary phosphor analysis shows such a scheme to be viable for use in a spectrally dynamic broadband general illumination source. A tunnel junction is envisioned as a means of current spreading in a buried layer for three terminal operation. However, tunnel junction properties in GaN based materials are not well understood, and require further optimization to be practical devices. Preliminary results on GaN tunnel junctions are presented here as well.

  3. Site-specific φ- and ψ-torsion angle determination in a uniformly/extensively 13C- and 15N-labeled peptide

    NASA Astrophysics Data System (ADS)

    Wi, Sungsool; Spano, Justin

    2011-10-01

    A solid-state rotational-echo double resonance (REDOR) NMR method was introduced to identify the ϕ- and ψ-torsion angle from a 1H- 15N or 1H- 13C' spin system of alanine-like residues in a selectively, uniformly, or extensively 15N-/ 13C-labeled peptide. When a C α( i) or a 15N peak is site-specifically obtainable in the NMR spectrum of a uniformly 15N/ 13C-labeled sample system, the ψ- or ϕ-torsion angle specified by the conformational structure of peptide geometry involving 15N( i)- 1H αi - 15N( i + 1) or 13C'( i - 1)- 1H Ni- 13C'( i) spin system can be identified based on 13C α- or 15N-detected 1H α- 15N or 1H N- 13C REDOR experiment. This method will conveniently be utilized to identify major secondary motifs, such as α-helix, β-sheet, and β-turn, from a uniformly 15N-/ 13C-labled peptide sample system. When tested on a 13C-/ 15N-labeled model system of a three amino acid peptide Gly-[U- 13C, 15N]Ala-[U- 13C, 15N]Leu, the ψ-angle of alanine obtained experimentally, ψ = -40 ± 30°, agreed reasonably well with the X-ray determined angle, ψ = -39°.

  4. High energy efficient solid state laser sources

    NASA Technical Reports Server (NTRS)

    Byer, Robert L.

    1987-01-01

    Diode-laser-pumped solid-state laser oscillators and nonlinear processes were investigated. A new generation on nonplanar oscillator was fabricated, and it is anticipated that passive linewidths will be pushed to the kilohertz regime. A number of diode-pumped laser transitions were demonstrated in the rod configuration. Second-harmonic conversion efficiencies as high as 15% are routinely obtained in a servo-locked external resonant doubling crystal at 15 mW cw input power levels at 1064 nm.

  5. High energy efficient solid state laser sources

    NASA Technical Reports Server (NTRS)

    Byer, Robert L.

    1987-01-01

    Investigations continue of diode-laser-pumped solid-state laser oscillators and nonlinear processes using them as sources. Diode laser array pumped Nd:YAG and Nd:glass lasers have been demonstrated. Theoretical studies of non-planar oscillators have been advanced, producing new designs which should be more resistant to feedback and offer better frequency stability. A monolithic, singly resonant Optical Parametric Oscillator in MgO:LiNbO3 has been operated.

  6. Solid state synthesis of poly(dichlorophosphazene)

    DOEpatents

    Allen, Christopher W.; Hneihen, Azzam S.; Peterson, Eric S.

    2001-01-01

    A method for making poly(dichlorophosphazene) using solid state reactants is disclosed and described. The present invention improves upon previous methods by removing the need for chlorinated hydrocarbon solvents, eliminating complicated equipment and simplifying the overall process by providing a "single pot" two step reaction sequence. This may be accomplished by the condensation reaction of raw materials in the melt phase of the reactants and in the absence of an environmentally damaging solvent.

  7. Solid-state-laser-rod holder

    DOEpatents

    Gettemy, D.J.; Barnes, N.P.; Griggs, J.E.

    1981-08-11

    The disclosure relates to a solid state laser rod holder comprising Invar, copper tubing, and epoxy joints. Materials and coefficients of expansion of the components of the holder combine with the rod to produce a joint which will give before the rod itself will. The rod may be lased at about 70 to 80/sup 0/K and returned from such a temperature to room temperature repeatedly without its or the holder's destruction.

  8. Ultimate gradient in solid-state accelerators

    SciTech Connect

    Whittum, D.H.

    1999-07-01

    We recall the motivation for research in high-gradient acceleration and the problems posed by a compact collider. We summarize the phenomena known to appear in operation of a solid-state structure with large fields, and research relevant to the question of the ultimate gradient. We take note of new concepts, and examine one in detail, a miniature particle accelerator based on an active millimeter-wave circuit and parallel particle beams. {copyright} {ital 1999 American Institute of Physics.}

  9. Ultimate gradient in solid-state accelerators

    SciTech Connect

    Whittum, D.H.

    1998-08-01

    The authors recall the motivation for research in high-gradient acceleration and the problems posed by a compact collider. They summarize the phenomena known to appear in operation of a solid-state structure with large fields, and research relevant to the question of the ultimate gradient. They take note of new concepts, and examine one in detail, a miniature particle accelerator based on an active millimeter-wave circuit and parallel particle beams.

  10. Ultimate gradient in solid-state accelerators

    SciTech Connect

    Whittum, David H.

    1999-07-12

    We recall the motivation for research in high-gradient acceleration and the problems posed by a compact collider. We summarize the phenomena known to appear in operation of a solid-state structure with large fields, and research relevant to the question of the ultimate gradient. We take note of new concepts, and examine one in detail, a miniature particle accelerator based on an active millimeter-wave circuit and parallel particle beams.

  11. Pulsed solid state lasers for medicine

    NASA Astrophysics Data System (ADS)

    Kertesz, Ivan; Danileiko, A. Y.; Denker, Boris I.; Kroo, Norbert; Osiko, Vyacheslav V.; Prokhorov, Alexander M.

    1994-02-01

    The effect on living tissues of different pulsed solid state lasers: Nd:YAG ((lambda) equals 1.06 micrometers ) Er:glass (1.54 micrometers ), Ho:YAG (2.1 micrometers ) and Er:YAG (2.94 micrometers ) is compared with the continuous wave Nd:YAG- and CO2-lasers used in operating theaters. Portable Er:glass- and Er:YAG-lasers are developed for surgery/cosmetics and HIV-safe blood testing.

  12. Flexible solid-state fabric based supercapacitor

    NASA Astrophysics Data System (ADS)

    Yong, S.; Owen, J. R.; Tudor, M. J.; Beeby, S. P.

    2015-12-01

    This paper reports details of the design, fabrication and characterisation of a solid- state fabric supercapacitor device. The proposed supercapacitors were based on fabric electrodes fabricated with low cost carbon materials via a spray coating technique. The two layer supercapacitors achieved a specific capacitances of 10.6 F.g-1, area capacitance of 71.8 mF.cm-2 and maintained 99% of the initial capacitance after cycling the device for more than 15000 times

  13. SPS solid state antenna power combiner

    NASA Technical Reports Server (NTRS)

    Fitzsimmons, G. W.

    1980-01-01

    A concept for a solar power satellite antenna power combiner which utilizes solid state dc-rf converters is described. To avoid the power combining losses associated with circuit hybrids it is proposed that the power from multiple solid state amplifiers be combined by direct coupling of each amplifier's output to the radiating antenna structure. The selected power-combining antenna consists of a printed (metalized) microstrip circuit on a ceramic type dielectric substrate which is backed by a shallow lightweight aluminum cavity which sums the power of four microwave sources. The antenna behaves like two one-half wavelength slot-line antennas coupled together via their common cavity structure. A significant feature of the antenna configuration selected is that the radiated energy is summed to yield a single radiated output phase which represents the average insertion phase of the four power amplifiers. This energy may be sampled and, by comparison with the input signal, one can phase error correct to maintain the insertion phase of all solid state power combining modules at exactly the same value. This insures that the insertion phase of each SPS power combining antenna module is identical. An experiment verification program is described.

  14. Optoacoustic 13C-breath test analyzer

    NASA Astrophysics Data System (ADS)

    Harde, Hermann; Helmrich, Günther; Wolff, Marcus

    2010-02-01

    The composition and concentration of exhaled volatile gases reflects the physical ability of a patient. Therefore, a breath analysis allows to recognize an infectious disease in an organ or even to identify a tumor. One of the most prominent breath tests is the 13C-urea-breath test, applied to ascertain the presence of the bacterium helicobacter pylori in the stomach wall as an indication of a gastric ulcer. In this contribution we present a new optical analyzer that employs a compact and simple set-up based on photoacoustic spectroscopy. It consists of two identical photoacoustic cells containing two breath samples, one taken before and one after capturing an isotope-marked substrate, where the most common isotope 12C is replaced to a large extent by 13C. The analyzer measures simultaneously the relative CO2 isotopologue concentrations in both samples by exciting the molecules on specially selected absorption lines with a semiconductor laser operating at a wavelength of 2.744 μm. For a reliable diagnosis changes of the 13CO2 concentration of 1% in the exhaled breath have to be detected at a concentration level of this isotope in the breath of about 500 ppm.

  15. Polymorphs of Theophylline Characterized by DNP Enhanced Solid-State NMR.

    PubMed

    Pinon, Arthur C; Rossini, Aaron J; Widdifield, Cory M; Gajan, David; Emsley, Lyndon

    2015-11-01

    We show how dynamic nuclear polarization (DNP) enhanced solid-state NMR spectroscopy can be used to characterize polymorphs and solvates of organic solids. We applied DNP to three polymorphs and one hydrated form of the asthma drug molecule theophylline. For some forms of theophylline, sample grinding and impregnation with the radical-containing solution, which are necessary to prepare the samples for DNP, were found to induce polymorphic transitions or desolvation between some forms. We present protocols for sample preparation for solid-state magic-angle spinning (MAS) DNP experiments that avoid the polymorphic phase transitions in theophylline. These protocols include cryogrinding, grinding under inert atmosphere, and the appropriate choice of the impregnating liquid. By applying these procedures, we subsequently demonstrate that two-dimensional correlation experiments, such as (1)H-(13)C and (1)H-(15)N HETCOR or (13)C-(13)C INADEQUATE, can be obtained at natural isotopic abundance in reasonable times, thus enabling more advanced structural characterization of polymorphs.

  16. Solid-state NMR investigation of effect of fluorination and methylation on prednisolone conformation.

    PubMed

    Carillo, Kathleen D; Arco, Susan; Wang, Cheng-Chung; Tzou, Der-Lii M

    2015-12-01

    Prednisolone (Prd) is a polymorphous synthetic corticosteroid that has three crystalline forms mediated by different solvents. In this study, we have demonstrated that solid-state {(1)H}(13)C cross-polarization/magic angle spinning (CP/MAS) NMR spectroscopy is able to resolve the effects of methylation and fluorination on the conformation of the steroidal rings in Prd. Two compounds were chosen for the study, 6-α-methylprednisolone (Prd-6M) and 6-α-fluoroprednisolone (Prd-6F). The (13)C signals of Prd-6F showed primarily doublet patterns, with splittings of 40-380 Hz, indicating multiple ring conformations, whereas the (13)C signals of Prd and Prd-6M exhibited a singlet pattern, indicating a unique conformation. Using evidence from chemical shift deviation and anisotropy analysis, we have demonstrated by solid-state NMR that Prd-6F adopts two different steroidal ring conformations that are different from that of Prd-6M, and less similar to that of unsubstituted Prd.

  17. Solid-state NMR studies of collagen-based parchments and gelatin.

    PubMed

    Aliev, Abil E

    2005-03-01

    Historical collagen-based parchments have been studied by solid-state NMR. In addition, new parchment (produced according to traditional methods) and gelatin from bovine skin were also studied. Wideline 1H and MAS 13C measurements were carried out directly on intact parchments. A simple approach is proposed for evaluation of the extent of parchment degradation based on the linewidth changes in the 13C CPMAS spectra relative to new parchment and gelatin. Structural (bound) water content was estimated from wideline 1H NMR lineshape and relaxation time measurements. It was found that the relative water content in parchments correlates linearly with 13C MAS linewidths. Its decrease on parchment degradation indicates that structural water molecules are of primary importance in stabilizing higher order collagen structures. Backbone and side chain dynamics of collagen in parchments were compared to those of gelatin based on the 13C dipolar-dephased experiments. Carbonyl 13C chemical shift anisotropies were measured to deduce the geometry of the collagen backbone motion. Unlike previous studies, we found that the collagen backbone motion is similar to that found in other proteins and occurs primarily via small-angle librations about internal bond directions.

  18. Structural Analysis of Nanoscale Self-Assembled Discoidal Lipid Bilayers by Solid-State NMR Spectroscopy

    PubMed Central

    Li, Ying; Kijac, Aleksandra Z.; Sligar, Stephen G.; Rienstra, Chad M.

    2006-01-01

    Nanodiscs are an example of discoidal nanoscale self-assembled lipid/protein particles similar to nascent high-density lipoproteins, which reduce the risk of coronary artery disease. The major protein component of high-density lipoproteins is human apolipoprotein A-I, and the corresponding protein component of Nanodiscs is membrane scaffold protein 1 (MSP1), a 200-residue lipid-binding domain of human apolipoprotein A-I. Here we present magic-angle spinning (MAS) solid-state NMR studies of uniformly 13C,15N-labeled MSP1 in polyethylene glycol precipitated Nanodiscs. Two-dimensional MAS 13C-13C correlation spectra show excellent microscopic order of MSP1 in precipitated Nanodiscs. Secondary isotropic chemical shifts throughout the protein are consistent with a predominantly helical structure. Moreover, the backbone conformations of prolines derived from their 13C chemical shifts are consistent with the molecular belt model but not the picket fence model of lipid-bound MSP1. Overall comparison of experimental spectra and 13C chemical shifts predicted from several structural models also favors the belt model. Our study thus supports the belt model of Nanodisc structure and demonstrates the utility of MAS NMR to study the structure of high molecular weight lipid-protein complexes. PMID:16905610

  19. Protein structure by solid-state NMR of oriented systems

    SciTech Connect

    Stewart, P.L.

    1987-01-01

    A method for determining protein backbone structure from angular information obtainable by solid state NMR spectroscopy is presented. Various spin interactions including quadrupole, dipole, and chemical shift interactions and nuclei including /sup 14/N, /sup 15/N, /sup 13/C, and /sup 2/H may be observed. Angularly dependent measurements can be made when the sample has at least one direction of order along the externally applied magnetic field. Several NMR parameters are used to determine the orientation of each peptide plane with respect to the magnetic field vector, B/sub O/, to within a few symmetry related possibilities. The computer program Totlink can then be used to perform the necessary coordinate transformations and to evaluate the possible backbone structures and select for the most chemically reasonable. Experimental /sup 14/N NMR structural studies of the model peptides n-acetyl-d,l-valine, n-acetyl-l-valyl-l-leucine, and l-alanyl-glycyl-glycine and preliminary /sup 14/N NMR results on a large single crystal of orthorhombic lysozyme are presented.

  20. Impact of Ho(3+)-doping on (13)C dynamic nuclear polarization using trityl OX063 free radical.

    PubMed

    Kiswandhi, Andhika; Niedbalski, Peter; Parish, Christopher; Kaur, Pavanjeet; Martins, André; Fidelino, Leila; Khemtong, Chalermchai; Song, Likai; Sherry, A Dean; Lumata, Lloyd

    2016-08-21

    We have investigated the effects of Ho-DOTA doping on the dynamic nuclear polarization (DNP) of [1-(13)C] sodium acetate using trityl OX063 free radical at 3.35 T and 1.2 K. Our results indicate that addition of 2 mM Ho-DOTA on 3 M [1-(13)C] sodium acetate sample in 1 : 1 v/v glycerol : water with 15 mM trityl OX063 improves the DNP-enhanced (13)C solid-state nuclear polarization by a factor of around 2.7-fold. Similar to the Gd(3+) doping effect on (13)C DNP, the locations of the positive and negative (13)C maximum polarization peaks in the (13)C microwave DNP sweep are shifted towards each other with the addition of Ho-DOTA on the DNP sample. W-band electron spin resonance (ESR) studies have revealed that while the shape and linewidth of the trityl OX063 ESR spectrum was not affected by Ho(3+)-doping, the electron spin-lattice relaxation time T1 of trityl OX063 was prominently reduced at cryogenic temperatures. The reduction of trityl OX063 electron T1 by Ho-doping is linked to the (13)C DNP improvement in light of the thermodynamic picture of DNP. Moreover, the presence of Ho-DOTA in the dissolution liquid at room temperature has negligible reduction effect on liquid-state (13)C T1, in contrast to Gd(3+)-doping which drastically reduces the (13)C T1. The results here suggest that Ho(3+)-doping is advantageous over Gd(3+) in terms of preservation of hyperpolarized state-an important aspect to consider for in vitro and in vivo NMR or imaging (MRI) experiments where a considerable preparation time is needed to administer the hyperpolarized (13)C liquid.

  1. Impact of Ho(3+)-doping on (13)C dynamic nuclear polarization using trityl OX063 free radical.

    PubMed

    Kiswandhi, Andhika; Niedbalski, Peter; Parish, Christopher; Kaur, Pavanjeet; Martins, André; Fidelino, Leila; Khemtong, Chalermchai; Song, Likai; Sherry, A Dean; Lumata, Lloyd

    2016-08-21

    We have investigated the effects of Ho-DOTA doping on the dynamic nuclear polarization (DNP) of [1-(13)C] sodium acetate using trityl OX063 free radical at 3.35 T and 1.2 K. Our results indicate that addition of 2 mM Ho-DOTA on 3 M [1-(13)C] sodium acetate sample in 1 : 1 v/v glycerol : water with 15 mM trityl OX063 improves the DNP-enhanced (13)C solid-state nuclear polarization by a factor of around 2.7-fold. Similar to the Gd(3+) doping effect on (13)C DNP, the locations of the positive and negative (13)C maximum polarization peaks in the (13)C microwave DNP sweep are shifted towards each other with the addition of Ho-DOTA on the DNP sample. W-band electron spin resonance (ESR) studies have revealed that while the shape and linewidth of the trityl OX063 ESR spectrum was not affected by Ho(3+)-doping, the electron spin-lattice relaxation time T1 of trityl OX063 was prominently reduced at cryogenic temperatures. The reduction of trityl OX063 electron T1 by Ho-doping is linked to the (13)C DNP improvement in light of the thermodynamic picture of DNP. Moreover, the presence of Ho-DOTA in the dissolution liquid at room temperature has negligible reduction effect on liquid-state (13)C T1, in contrast to Gd(3+)-doping which drastically reduces the (13)C T1. The results here suggest that Ho(3+)-doping is advantageous over Gd(3+) in terms of preservation of hyperpolarized state-an important aspect to consider for in vitro and in vivo NMR or imaging (MRI) experiments where a considerable preparation time is needed to administer the hyperpolarized (13)C liquid. PMID:27424954

  2. Solid state structural and theoretical investigations of a biologically active chalcone

    NASA Astrophysics Data System (ADS)

    Abbas, Asghar; Gökce, Halil; Bahceli, Semiha; Bolte, Michael; Naseer, Muhammad Moazzam

    2016-05-01

    The computational methods are presently emerging as an efficient and reliable tool for predicting structural properties of biologically important compounds. In the present manuscript, the solid state structural and theoretical investigations of a biologically active chalcone i-e (E)-3-(4-(hexyloxy)phenyl)-1-phenylprop-2-en-1-one (6c) have been reported. The solid state structure of 6c was measured by X-ray crystallographic technique whereas the optimized molecular geometry, vibrational frequencies, the simulated UV-vis spectra (in gas and in methanol solvent), 1H and 13C NMR chemical shift (in gas and in chloroform solvent) values, HOMO-LUMO analysis, the molecular electrostatic potential (MEP) surface and thermodynamic parameters were calculated by using DFT/B3LYP method with 6-311++G(d,p) basis set in ground state. The results of the theoretical investigations were found to be in good agreement with experimental data.

  3. Application and Reliability of Solid-State NMR in Environmental Sciences

    NASA Astrophysics Data System (ADS)

    Knicker, Heike

    2010-05-01

    For the characterization of soil organic matter, a suite of analytical approaches are available. Chemical degradative methods involve an extraction scheme with which the soluble part of the mixture is isolated and analyzed by colorimetrical or chromatographic means. Macromolecular structures can be subjected to thermolytic or combined thermochemolytic degradation. Because secondary reactions (rearrangement, cracking, hydrogenation and polymerization) in a heterogeneous mixture cannot be excluded, it is obvious that conclusions regarding the original structure in the macromolecular phase have to be drawn with caution. A powerful alternative represents solid-state nuclear magnetic resonance (NMR) spectroscopy, allowing the examination of the bulk sample without major pre-treatment In environmental sciences, this technique mostly involves the isotope 13C to study the chemical composition of organic matter in soils, sediments or compost to study the temporal development of humic material or chemical alterations due to variation in environmental parameters. Due to its low sensibility solid-state 15N NMR studies on such samples are only found occasionally. The emphasis of solid-state NMR spectroscopy is not only to determine the gross chemical composition of the material under study via a chemical shift assignment but also a quantitative correlation between the different signal intensities and the relative contribution of the respective C or N types to the total organic C or N content. However, despite increasing popularity, this approach is still viewed as mysterious techniques, in particular with respect to quantification. Accordingly, the purpose of this review is to give a short overview on the possibilities and limitations of this technique in environmental science and in particular for the study of soil organic matter. In general, solid-state 13C NMR spectra of soil organic matter are obtained with the cross polarization magic angle spinning (CPMAS) technique. This

  4. A method for simultaneous echo planar imaging of hyperpolarized 13C pyruvate and 13C lactate

    NASA Astrophysics Data System (ADS)

    Reed, Galen D.; Larson, Peder E. Z.; von Morze, Cornelius; Bok, Robert; Lustig, Michael; Kerr, Adam B.; Pauly, John M.; Kurhanewicz, John; Vigneron, Daniel B.

    2012-04-01

    A rapid echo planar imaging sequence for dynamic imaging of [1-13C] lactate and [1-13C] pyruvate simultaneously was developed. Frequency-based separation of these metabolites was achieved by spatial shifting in the phase-encoded direction with the appropriate choice of echo spacing. Suppression of the pyruvate-hydrate and alanine resonances is achieved through an optimized spectral-spatial RF waveform. Signal sampling efficiency as a function of pyruvate and lactate excitation angle was simulated using two site exchange models. Dynamic imaging is demonstrated in a transgenic mouse model, and phantom validations of the RF pulse frequency selectivity were performed.

  5. Modification of solid state CdZnTe (CZT) radiation detectors with high sensitivity or high resolution operation

    SciTech Connect

    Washington, II, Aaron L; Duff, Martine C; Teague, Lucile C; Burger, Arnold; Groza, Michael

    2014-11-11

    An apparatus and process is provided to illustrate the manipulation of the internal electric field of CZT using multiple wavelength light illumination on the crystal surface at RT. The control of the internal electric field is shown through the polarization in the IR transmission image under illumination as a result of the Pockels effect.

  6. BOOK REVIEW: Solid State Physics: An Introduction

    NASA Astrophysics Data System (ADS)

    Jakoby, Bernhard

    2009-07-01

    There's a wealth of excellent textbooks on solid state physics. The author of the present book is well aware of this fact and does not attempt to write just another one. Rather, he has provided a very compact introduction to solid state physics for third-year students. As we are faced with the continuous appearance interdisciplinary fields and associated study curricula in natural and engineering sciences (biophysics, mechatronics, etc), a compact text in solid state physics would be appreciated by students of these disciplines as well. The book features 11 chapters where each is provided with supplementary discussion questions and problems. The first chapters deal with a review of chemical bonding mechanisms, crystal structures and mechanical properties of solids, which are brief but by no means superficial. The following, somewhat more detailed chapter on thermal properties of lattices includes a nice introduction to phonons. The foundations of solid state electronics are treated in the next three chapters. Here the author first discusses the classical treatment of electronic behaviour in metals (Drude model) and continues with a quantum-theoretical approach starting with the free-electron model and leading to the band structures in conductive solids. The next chapter is devoted to semiconductors and ends with a brief but, with respect to the topical scope, adequate discussion of semiconductor devices. The classical topics of magnetic and dielectric behaviour are treated in the sequel. The book closes with a chapter on superconductivity and a brief chapter covering the modern topics of quantum confinement and aspects of nanoscale physics. In my opinion, the author has succeeded in creating a very concise yet not superficial textbook. The account presented often probes subjects deep enough to lay the basis for a thorough understanding, preparing the reader for more specialized textbooks. For instance, I think that this book may serve as an excellent first

  7. Deformation-induced localized solid-state amorphization in nanocrystalline nickel

    PubMed Central

    Han, Shuang; Zhao, Lei; Jiang, Qing; Lian, Jianshe

    2012-01-01

    Although amorphous structures have been widely obtained in various multi-component metallic alloys, amorphization in pure metals has seldom been observed and remains a long-standing scientific curiosity and technological interest. Here we present experimental evidence of localized solid-state amorphization in bulk nanocrystalline nickel introduced by quasi-static compression at room temperature. High-resolution electron microscope observations illustrate that nano-scale amorphous structures present at the regions where severe deformation occurred, e.g. along crack paths or surrounding nano-voids. These findings have indicated that nanocrystalline structures are highly desirable for promoting solid-state amorphization, which may provide new insights for understanding the nature of the crystalline-to-amorphous transformation and suggested a potential method to produce elemental metallic glasses that have hardly been available hitherto through rapid solidification. PMID:22768383

  8. Compact solid-state laser source for 1S-2S spectroscopy in atomic hydrogen

    SciTech Connect

    Kolachevsky, N.; Alnis, J.; Bergeson, S. D.; Haensch, T. W.

    2006-02-15

    We demonstrate a compact solid-state laser source for high-resolution two-photon spectroscopy of the 1S-2S transition in atomic hydrogen. The source emits up to 20 mW at 243 nm and consists of a 972 nm diode laser, a tapered amplifier, and two doubling stages. The diode laser is actively stabilized to a high-finesse cavity. We compare the new source to the stable 486 nm dye laser used in previous experiments and record 1S-2S spectra using both systems. With the solid-state laser system, we demonstrate a resolution of the hydrogen spectrometer of 6x10{sup 11}, which is promising for a number of high-precision measurements in hydrogenlike systems.

  9. Solid-state phased array (SSPA) performance

    NASA Astrophysics Data System (ADS)

    Kley, Robert C., Jr.; Hull, W. Porter, Jr.; Lamb, Franklin D.

    The solid-state phased-array (SSPA) is an active electronically scanned array (AESA) designed and built for airborne radar applications using transmit/receive module hybrid technology. Details of its subassemblies and results of testing the array and its subassemblies are presented. The SSPA T/R (transmit/receive) modules used a hybrid construction that is labor-intensive and leads to parameter variations. The next generation of modules uses monolithic microwave integrated circuit (MMIC) devices, which will result in more uniform parameters and lower manufacturing cost.

  10. Passivation-free solid state battery

    DOEpatents

    Abraham, Kuzhikalail M.; Peramunage, Dharmasena

    1998-01-01

    This invention pertains to passivation-free solid-state rechargeable batteries composed of Li.sub.4 Ti.sub.5 O.sub.12 anode, a solid polymer electrolyte and a high voltage cathode. The solid polymer electrolyte comprises a polymer host, such as polyacrylonitrile, poly(vinyl chloride), poly(vinyl sulfone), and poly(vinylidene fluoride), plasticized by a solution of a Li salt in an organic solvent. The high voltage cathode includes LiMn.sub.2 O.sub.4, LiCoO.sub.2, LiNiO.sub.2 and LiV.sub.2 O.sub.5 and their derivatives.

  11. Passivation-free solid state battery

    DOEpatents

    Abraham, K.M.; Peramunage, D.

    1998-06-16

    This invention pertains to passivation-free solid-state rechargeable batteries composed of Li{sub 4}Ti{sub 5}O{sub 12} anode, a solid polymer electrolyte and a high voltage cathode. The solid polymer electrolyte comprises a polymer host, such as polyacrylonitrile, poly(vinyl chloride), poly(vinyl sulfone), and poly(vinylidene fluoride), plasticized by a solution of a Li salt in an organic solvent. The high voltage cathode includes LiMn{sub 2}O{sub 4}, LiCoO{sub 2}, LiNiO{sub 2} and LiV{sub 2}O{sub 5} and their derivatives. 5 figs.

  12. Fast-neutron solid-state dosimeter

    DOEpatents

    Kecker, K.H.; Haywood, F.F.; Perdue, P.T.; Thorngate, J.H.

    1975-07-22

    This patent relates to an improved fast-neutron solid-state dosimeter that does not require separation of materials before it can be read out, that utilizes materials that do not melt or otherwise degrade at about 300$sup 0$C readout temperature, that provides a more efficient dosimeter, and that can be reused. The dosimeters are fabricated by intimately mixing a TL material, such as CaSO$sub 4$:Dy, with a powdered polyphenyl, such as p-sexiphenyl, and hot- pressing the mixture to form pellets, followed by out-gassing in a vacuum furnace at 150$sup 0$C prior to first use dosimeters. (auth)

  13. Pulsed Power for Solid-State Lasers

    SciTech Connect

    Gagnon, W; Albrecht, G; Trenholme, J; Newton, M

    2007-04-19

    Beginning in the early 1970s, a number of research and development efforts were undertaken at U.S. National Laboratories with a goal of developing high power lasers whose characteristics were suitable for investigating the feasibility of laser-driven fusion. A number of different laser systems were developed and tested at ever larger scale in pursuit of the optimum driver for laser fusion experiments. Each of these systems had associated with it a unique pulsed power option. A considerable amount of original and innovative engineering was carried out in support of these options. Ultimately, the Solid-state Laser approach was selected as the optimum driver for the application. Following this, the Laser Program at the Lawrence Livermore National Laboratory and the University of Rochester undertook aggressive efforts directed at developing the technology. In particular, at Lawrence Livermore National Laboratory, a series of laser systems beginning with the Cyclops laser and culminating in the present with the National Ignition Facility were developed and tested. As a result, a large amount of design information for solid-state laser pulsed power systems has been documented. Some of it is in the form of published papers, but most of it is buried in internal memoranda, engineering reports and LLNL annual reports. One of the goals of this book is to gather this information into a single useable format, such that it is easily accessed and understood by other engineers and physicists for use with future designs. It can also serve as a primer, which when seriously studied, makes the subsequent reading of original work and follow-up references considerably easier. While this book deals only with the solid-state laser pulsed power systems, in the bibliography we have included a representative cross section of papers and references from much of the very fine work carried out at other institutions in support of different laser approaches. Finally, in recent years, there has

  14. Solid-state turn coordinator display

    NASA Technical Reports Server (NTRS)

    Meredith, B. D.; Crouch, R. K.; Kelly, W. L., IV

    1975-01-01

    A solid state turn coordinator display which employs light emitting diodes (LED's) as the display medium was developed to demonstrate the feasibility of such displays for aircraft applications. The input to the display is supplied by a fluidic inertial rate sensor used in an aircraft wing leveler system. The display is composed of the LED radial display face and the electronics necessary to address and drive the individual lines of LED's. Three levels of brightness are provided to compensate for the different amounts of ambient light present in the cockpit.

  15. Network control architecture for solid state lighting

    NASA Astrophysics Data System (ADS)

    Ducharme, Alfred D.; Morgan, Fritz

    2001-12-01

    At the current time most of the attention in the solid-state lighting field has been placed on the blue and white light emitting diodes (LEDs). It has and will continue to be extremely important to concentrate on increasing the efficiencies of these devices. However, one of the most overlooked benefits of LEDs is that they are intrinsically simple to control. In this paper, the authors will discuss a technology that is currently being developed to enable fixtures incorporating LED light engines to be connected to a digital lighting network. A description of such a network enabling device and the results from a technology demonstration of a prototype system are provided.

  16. Entanglement and Squeezing in Solid State Circuits

    SciTech Connect

    Wen Yihuo; Gui Lulong

    2008-11-07

    We investigate the dynamics of a system consisting of a Cooper-pair box and two superconducting transmission line resonators. There exist both linear and nonlinear interactions in such a system. We show that single-photon entanglement state can be generated in a simple way in the linear interaction regime. In nonlinear interaction regime, we derive the Hamiltonian of degenerate three-wave mixing and propose a scheme for generating squeezed state of microwave using the three-wave mixing in solid state circuits. In the following, we design a system for generating squeezed states of nanamechanical resonator.

  17. The solid state area scanner photometer

    NASA Astrophysics Data System (ADS)

    Rakos, K. D.

    The design and operation of a solid-state area-scanner photometer for observations of binaries are reported. Tracking and seeing errors are shown to be more significant than photoelectron statistics in determining overall accuracy; hence a system using individually recorded short scans and computer processing is adopted. A linear self-scanned photodiode array comprising 128 discrete Si photodiodes arranged on a 2.5 x 3.2-mm surface with virtually no dead space and having 80-percent quantum efficiency is used on a 1-m telescope at 1-sec integration time with thermoelectric cooling to -30 C. Good accuracy is obtained for binaries of magnitude 10 or less.

  18. The Galileo Solid-State Imaging experiment

    NASA Technical Reports Server (NTRS)

    Belton, Michael J. S.; Klaasen, Kenneth P.; Clary, Maurice C.; Anderson, James L.; Anger, Clifford D.; Carr, Michael H.; Chapman, Clark R.; Davies, Merton E.; Greeley, Ronald; Anderson, Donald

    1992-01-01

    The Galileo Orbiter's Solid-State Imaging (SSI) experiment uses a 1.5-m focal length TV camera with 800 x 800 pixel, virtual-phase CCD detector in order to obtain images of Jupiter and its satellites which possess a combination of sensitivity levels, spatial resolutions, geometric fidelity, and spectral range that are unmatched by earlier imaging data. After describing the performance of this equipment on the basis of ground calibrations, attention is given to the SSI experiment's Jupiter system observation objectives; these encompass atmospheric science, satellite surfaces, ring structure, and 'darkside' experiments.

  19. Nanoengineering for solid-state lighting.

    SciTech Connect

    Schubert, E. Fred; Koleske, Daniel David; Wetzel, Christian; Lee, Stephen Roger; Missert, Nancy A.; Lin, Shawn-Yu; Crawford, Mary Hagerott; Fischer, Arthur Joseph

    2009-09-01

    This report summarizes results from a 3-year Laboratory Directed Research and Development project performed in collaboration with researchers at Rensselaer Polytechnic Institute. Our collaborative effort was supported by Sandia's National Institute for Nanoengineering and focused on the study and application of nanoscience and nanoengineering concepts to improve the efficiency of semiconductor light-emitting diodes for solid-state lighting applications. The project explored LED efficiency advances with two primary thrusts: (1) the study of nanoscale InGaN materials properties, particularly nanoscale crystalline defects, and their impact on internal quantum efficiency, and (2) nanoscale engineering of dielectric and metal materials and integration with LED heterostructures for enhanced light extraction efficiency.

  20. Solid-state-based analog of optomechanics

    DOE PAGES

    Naumann, Nicolas L.; Droenner, Leon; Carmele, Alexander; Chow, Weng W.; Kabuss, Julia

    2016-06-21

    In this study, we investigate a semiconductor quantum dot as a microscopic analog of a basic optomechanical setup. We show that optomechanical features can be reproduced by the solid-state platform, arising from parallels of the underlying interaction processes, which in the optomechanical case is the radiation pressure coupling and in the semiconductor case the electron–phonon coupling. We discuss bistabilities, lasing, and phonon damping, and recover the same qualitative behaviors for the semiconductor and the optomechanical cases expected for low driving strengths. However, in contrast to the optomechanical case, distinct signatures of higher order processes arise in the semiconductor model.

  1. Solid state transport-based thermoelectric converter

    DOEpatents

    Hu, Zhiyu

    2010-04-13

    A solid state thermoelectric converter includes a thermally insulating separator layer, a semiconducting collector and an electron emitter. The electron emitter comprises a metal nanoparticle layer or plurality of metal nanocatalyst particles disposed on one side of said separator layer. A first electrically conductive lead is electrically coupled to the electron emitter. The collector layer is disposed on the other side of the separator layer, wherein the thickness of the separator layer is less than 1 .mu.m. A second conductive lead is electrically coupled to the collector layer.

  2. Programmable solid state atom sources for nanofabrication

    NASA Astrophysics Data System (ADS)

    Han, Han; Imboden, Matthias; Stark, Thomas; Del Corro, Pablo G.; Pardo, Flavio; Bolle, Cristian A.; Lally, Richard W.; Bishop, David J.

    2015-06-01

    In this paper we discuss the development of a MEMS-based solid state atom source that can provide controllable atom deposition ranging over eight orders of magnitude, from ten atoms per square micron up to hundreds of atomic layers, on a target ~1 mm away. Using a micron-scale silicon plate as a thermal evaporation source we demonstrate the deposition of indium, silver, gold, copper, iron, aluminum, lead and tin. Because of their small sizes and rapid thermal response times, pulse width modulation techniques are a powerful way to control the atomic flux. Pulsing the source with precise voltages and timing provides control in terms of when and how many atoms get deposited. By arranging many of these devices into an array, one has a multi-material, programmable solid state evaporation source. These micro atom sources are a complementary technology that can enhance the capability of a variety of nano-fabrication techniques.In this paper we discuss the development of a MEMS-based solid state atom source that can provide controllable atom deposition ranging over eight orders of magnitude, from ten atoms per square micron up to hundreds of atomic layers, on a target ~1 mm away. Using a micron-scale silicon plate as a thermal evaporation source we demonstrate the deposition of indium, silver, gold, copper, iron, aluminum, lead and tin. Because of their small sizes and rapid thermal response times, pulse width modulation techniques are a powerful way to control the atomic flux. Pulsing the source with precise voltages and timing provides control in terms of when and how many atoms get deposited. By arranging many of these devices into an array, one has a multi-material, programmable solid state evaporation source. These micro atom sources are a complementary technology that can enhance the capability of a variety of nano-fabrication techniques. Electronic supplementary information (ESI) available: A document containing further information about device characterization

  3. High temperature solid state storage cell

    DOEpatents

    Rea, Jesse R.; Kallianidis, Milton; Kelsey, G. Stephen

    1983-01-01

    A completely solid state high temperature storage cell comprised of a solid rechargeable cathode such as TiS.sub.2, a solid electrolyte which remains solid at the high temperature operating conditions of the cell and which exhibits high ionic conductivity at such elevated temperatures such as an electrolyte comprised of lithium iodide, and a solid lithium or other alkali metal alloy anode (such as a lithium-silicon alloy) with 5-50% by weight of said anode being comprised of said solid electrolyte.

  4. Solid State Marx Modulators for Emerging Applications

    SciTech Connect

    Kemp, M.A.; /SLAC

    2012-09-14

    Emerging linear accelerator applications increasingly push the boundaries of RF system performance and economics. The power modulator is an integral part of RF systems whose characteristics play a key role in the determining parameters such as efficiency, footprint, cost, stability, and availability. Particularly within the past decade, solid-state switch based modulators have become the standard in high-performance, high power modulators. One topology, the Marx modulator, has characteristics which make it particularly attractive for several emerging applications. This paper is an overview of the Marx topology, some recent developments, and a case study of how this architecture can be applied to a few proposed linear accelerators.

  5. High resolution magnetic spectrometer SHARAQ in RIBF

    SciTech Connect

    Shimoura, S.

    2007-05-22

    For a new spectroscopy of nuclei using intense RI beams at RIBF, we started the SHARAQ project where a high-resolution SHARAQ spectrometer is being constructed together with a high-resolution secondary beam line. Physics motivation and the specification of the spectrometer are presented.

  6. High resolution scintillation detector with semiconductor readout

    DOEpatents

    Levin, Craig S.; Hoffman, Edward J.

    2000-01-01

    A novel high resolution scintillation detector array for use in radiation imaging such as high resolution Positron Emission Tomography (PET) which comprises one or more parallelepiped crystals with at least one long surface of each crystal being in intimate contact with a semiconductor photodetector such that photons generated within each crystal by gamma radiation passing therethrough is detected by the photodetector paired therewith.

  7. High Resolution PDF Measurements on Ag Nanoparticles

    SciTech Connect

    Rocha, Tulio C. R.; Martin, Chris; Kycia, Stefan; Zanchet, Daniela

    2009-01-29

    The quantitative analysis of structural defects in Ag nanoparticles was addressed in this work. We performed atomic scale structural characterization by a combination of x-ray diffraction (XRD) using the Pair Distribution Function analysis (PDF) and High Resolution Transmission Electron Microscopy (HRTEM). The XRD measurements were performed using an innovative instrumentation setup to provide high resolution PDF patterns.

  8. Rapid and accurate determination of the lignin content of lignocellulosic biomass by solid-state NMR.

    PubMed

    Fu, Li; McCallum, Scott A; Miao, Jianjun; Hart, Courtney; Tudryn, Gregory J; Zhang, Fuming; Linhardt, Robert J

    2015-02-01

    Biofuels and biomaterials, produced from lignocellulosic feedstock, require facile access to cellulose and hemicellulose to be competitive with petroleum processing and sugar-based fermentation. Physical-chemical barriers resulting from lignin complicates the hydrolysis biomass into fermentable sugars. Thus, the amount of lignin within a substrate is critical in determining biomass processing. The application of (13)C cross-polarization, magic-angle spinning, and solid-state nuclear magnetic resonance for the direct quantification of lignin content in biomass is examined. Using a standard curve constructed from pristine lignin and cellulose, the lignin content of a biomass sample is accurately determined through direct measurement without chemical or enzymatic pre-treatment.

  9. Sobrerol enantiomers and racemates: solid-state spectroscopy, thermal behavior, and phase diagrams.

    PubMed

    Bettinetti, G; Giordano, F; Fronza, G; Italia, A; Pellegata, R; Villa, M; Ventura, P

    1990-06-01

    The characterization of the solid state of sobrerol enantiomers and racemates has been accomplished by a number of techniques on solid phase such as thermal analysis (DSC) and spectroscopy (IR, 13C NMR, and X-ray diffraction both on powders and on single crystal). Experimental and theoretical binary phase diagrams of cis- and trans-sobrerol enantiomers and their mixtures have been drawn and are discussed. Thermal analysis allowed, moreover, the detection of cis racemate polymorphism. Finally, the quantitative analysis of the cis racemate as an impurity of the trans racemate by means of microcalorimetric determinations is reported.

  10. Synthesis Of 2h- And 13c-Substituted Dithanes

    DOEpatents

    Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.

    2004-05-04

    The present invention is directed to labeled compounds, [2-.sup.13 C]dithane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to processes of preparing [2-.sup.13 C]dithane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to labeled compounds, e.g., [.sup.2 H.sub.1-2, .sup.13 C]methanol (arylthio)-, acetates wherein the .sup.13 C atom is directly bonded to exactly one or two deuterium atoms.

  11. Synthesis of 2H- and 13C-substituted dithanes

    DOEpatents

    Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.

    2003-01-01

    The present invention is directed to labeled compounds, [2-.sup.13 C]dithiane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to processes of preparing [2-.sup.13 C]dithiane wherein the .sup.13 C atom is directly bonded to one or two deuterium atoms. The present invention is also directed to labeled compounds, e.g., [.sup.2 H.sub.1-2, .sup.13 C]methanol (arylthio)-, acetates wherein the .sup.13 C atom is directly bonded to exactly one or two deuterium atoms.

  12. Calculation of total meal d13C from individual food d13C.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Variations in the isotopic signature of carbon in biological samples can be used to distinguish dietary patterns and monitor shifts in metabolism. But for these variations to have meaning, the isotopic signature of the diet must be known. We sought to determine if knowledge of the 13C isotopic abund...

  13. In vivo dynamic turnover of cerebral 13C isotopomers from [U- 13C]glucose

    NASA Astrophysics Data System (ADS)

    Xu, Su; Shen, Jun

    2006-10-01

    An INEPT-based 13C MRS method and a cost-effective and widely available 11.7 Tesla 89-mm bore vertical magnet were used to detect dynamic 13C isotopomer turnover from intravenously infused [U- 13C]glucose in a 211 μL voxel located in the adult rat brain. The INEPT-based 1H → 13C polarization transfer method is mostly adiabatic and therefore minimizes signal loss due to B 1 inhomogeneity of the surface coils used. High quality and reproducible data were acquired as a result of combined use of outer volume suppression, ISIS, and the single-shot three-dimensional localization scheme built in the INEPT pulse sequence. Isotopomer patterns of both glutamate C4 at 34.00 ppm and glutamine C4 at 31.38 ppm are dominated first by a doublet originated from labeling at C4 and C5 but not at C3 (with 1JC4C5 = 51 Hz) and then by a quartet originated from labeling at C3, C4, and C5 (with 1JC3C4 = 35 Hz). A lag in the transition of glutamine C4 pattern from doublet-dominance to quartet dominance as compared to glutamate C4 was observed, which provides an independent verification of the precursor-product relationship between neuronal glutamate and glial glutamine and a significant intercompartmental cerebral glutamate-glutamine cycle between neurons and glial cells.

  14. Dynamic Nuclear Polarization (DNP) solid-state NMR spectroscopy, a new approach to study humic material?

    NASA Astrophysics Data System (ADS)

    Knicker, Heike; Lange, Sascha; van Rossum, Barth; Oschkinat, Hartmut

    2016-04-01

    Compared to solution NMR spectroscopy, solid-state NMR spectra suffer from broad resonance lines and low resolution. This could be overcome by the use of 2-dimenstional solid-state NMR pulse sequences. Until recently, this approach has been unfeasible as a routine tool in soil chemistry, mainly because of the low NMR sensitivity of the respective samples. A possibility to circumvent those sensitivity problems represents high-field Dynamic Nuclear Polarization (DNP) solid-state NMR spectroscopy (Barnes et al., 2008), allowing considerable signal enhancements (Akbey et al., 2010). This is achieved by a microwave-driven transfer of polarization from a paramagnetic center to nuclear spins. Application of DNP to MAS spectra of biological systems (frozen solutions) showed enhancements of the factor 40 to 50 (Hall et al., 1997). Enhancements of this magnitude, thus may enable the use of at least some of the 2D solid-state NMR techniques that are presently already applied for pure proteins but are difficult to apply to soil peptides in their complex matrix. After adjusting the required acquisition parameters to the system "soil organic matter", lower but still promising enhancement factors were achieved. Additional optimization was performed and allowed the acquisition of 2D 13C and 15N solid-state NMR spectra of humified 13C and 15N enriched plant residues. Within the present contribution, the first solid-state DNP NMR spectra of humic material are presented. Those data demonstrate the great potential of this approach which certainly opens new doors for a better understanding of biochemical processes in soils, sediments and water. Akbey, Ü., Franks, W.T., Linden, A., Lange, S., Griffin, R.G., van Rossum, B.-J., Oschkinat, H., 2010. Dynamic nuclear polarization of deuterated proteins. Angewandte Chemie International Edition 49, 7803-7806. Barnes, A.B., De Paëpe, G., van der Wel, P.C.A., Hu, K.N., Joo, C.G., Bajaj, V.S., Mak-Jurkauskas, M.L., Sirigiri, J.R., Herzfeld, J

  15. Structural studies of methyl brevifolincarboxylate in solid state by means of NMR spectroscopy and DFT calculations

    NASA Astrophysics Data System (ADS)

    Wolniak, Michał; Tomczyk, Michał; Gudej, Jan; Wawer, Iwona

    2006-12-01

    Methyl brevifolincarboxylate isolated from the herb of Potentilla argentea L. (Rosaceae) is a representative of the naturally occurring polyphenols. The compound is of pharmaceutical interest mainly because of its antiviral and antioxidant properties. 13C NMR spectra were recorded for solution and solid phase. 13C CPMAS spectra were assigned by comparison with solution data, dipolar dephasing and short contact time experiments. The correctness of assignments was verified by GIAO DFT calculations of shielding constants. The differences between the solution and solid state chemical shift values were explained in terms of orientation of OH groups and intramolecular hydrogen bonds. The splitting of the C1 dbnd O resonance shows that there exists a polymorphism in the solid phase, which might be due to the formation of intramolecular hydrogen bond involving carbonyl or methoxy oxygen (i.e. C10 sbnd OH⋯O dbnd C or C10 sbnd OH⋯OCH 3).

  16. Reorientation phenomena in imidazolium methyl sulfonate as probed by advanced solid-state NMR.

    PubMed

    Goward, Gillian R; Saalwächter, Kay; Fischbach, Ingrid; Spiess, Hans Wolfgang

    2003-01-01

    Evidence for reorientation of imidazolium rings in imidazolium methylsulfonate is demonstrated using solid-state NMR. This material is a model system for exciting new proton-conducting materials based on imidazole. Two advanced NMR methods, including 1H-13C and 1H-15N recoupled polarization transfer with dipolar sideband pattern analysis and analysis of the coalescence of 13C lineshapes are used to characterize the ring reorientation. The process is found to occur at temperatures well below the melting point of the salt, between 240 and 380 K, and is described by a single activation energy, of 38+/-5 kJ/mol. This material is considered as a model system for quantifying the ring reorientation process, which is often proposed to be the rate-limiting step in proton transport in imidazole-based proton conducting materials.

  17. Solid state lighting and photobiological safety

    NASA Astrophysics Data System (ADS)

    Soskind, Y. G.; Campin, J. A.; Hopler, M. D.; Pettit, G. H.

    2007-02-01

    Recent advancements in Light-Emitting Diode (LED) technology have led to significant proliferation of solid-state lighting in our every-day life. White light and monochrome LED-based solid-state sources provide a small size, lower power consumption, and longer life alternative to several types of traditional light sources, such as incandescent lights. However, the spectral characteristics of LEDs are significantly different from the spectra of self-luminous objects that human eyes are adapted to through evolution and, therefore, may pose a real threat of photic-induced eye injury. In this paper the spectral characteristics of individual sources are considered from a photobiological safety perspective, and are used to estimate the retinal hazard potential of LEDs relative to that for daylight and blackbody radiators. The presented LED source retinal hazard exposure ranking considerations could be accounted for during illumination system design to minimize photic-induced eye injury risk. The importance of the material presented herein can not be underestimated since high power LED sources are found in a variety of high volume lighting applications and systems including automotive lamps, signal lighting, flash lights and other illumination devices.

  18. Nanocrystal-enabled solid state bonding.

    SciTech Connect

    San Diego State University, San Diego, CA; Puskar, Joseph David; Tikare, Veena; Garcia Cardona, Cristina; Reece, Mark; Brewer, Luke N.; Holm, Elizabeth Ann

    2010-10-01

    In this project, we performed a preliminary set of sintering experiments to examine nanocrystal-enabled diffusion bonding (NEDB) in Ag-on-Ag and Cu-on-Cu using Ag nanoparticles. The experimental test matrix included the effects of material system, temperature, pressure, and particle size. The nanoparticle compacts were bonded between plates using a customized hot press, tested in shear, and examined post mortem using microscopy techniques. NEDB was found to be a feasible mechanism for low-temperature, low-pressure, solid-state bonding of like materials, creating bonded interfaces that were able to support substantial loads. The maximum supported shear strength varied substantially within sample cohorts due to variation in bonded area; however, systematic variation with fabrication conditions was also observed. Mesoscale sintering simulations were performed in order to understand whether sintering models can aid in understanding the NEDB process. A pressure-assisted sintering model was incorporated into the SPPARKS kinetic Monte Carlo sintering code. Results reproduce most of the qualitative behavior observed in experiments, indicating that simulation can augment experiments during the development of the NEDB process. Because NEDB offers a promising route to low-temperature, low-pressure, solid-state bonding, we recommend further research and development with a goal of devising new NEDB bonding processes to support Sandia's customers.

  19. Characterization of Solid State Ultracold Neutron Detectors

    NASA Astrophysics Data System (ADS)

    Sallaska, Anne; Garcia, Alejandro; Sjue, Sky; Hoedl, Seth; Melconian, Dan; Young, Albert; Holley, Adam; Geltenbort, Peter

    2006-05-01

    The reflective properties of ultracold neutrons (UCN) enable easy transport and bottling but make neutron detection a technical challenge. Typically, UCN are allowed to accelerate in the Earth's gravitational field to sufficient velocity to penetrate an aluminum entrance window of a ^3He proportional counter. Here we describe the construction and characterization at the ILL of two kinds of prototype solid-state detectors which can be used to monitor the UCN density inside the UCNA spectrometer at LANL without gravitational acceleration, and perhaps more critically, without the danger of ^3He leaks. The first type consists of 300 μg/cm^2 of LiF evaporated onto 200 nm thick Ni foils. The second type consists of ˜ 10^18 ^10B ions implanted in a 200 nm thick V layer, also evaporated onto Ni foils. From monte carlo simulations, we find that LiF has a critical velocity nearly equal to that of aluminum, whereas the boron foils do indeed have a lower cutoff. Because of these cutoffs and the small size of the detectors, our solid-state detectors, thus, equal (for LiF) or outperform (for Boron) aluminum window proportional counters for in-situ density measurements.

  20. In situ solid-state NMR study of methanol-to-gasoline chemistry in zeolite HZSM-5

    SciTech Connect

    Munson, E.J.; Kheir, A.A.; Lazo, N.D.; Haw, J.F.

    1992-09-17

    This paper uses {sup 13}C solid-state NMR to study the chemistry of a variety of absorbates related to the methanol-to-gasoline process. This study has resulted in a better understanding of the chemical reaction occurring inside the zeolite HZSM-5 used in this process. It is shown that ethylene is the first olefin formed and ethyl methyl ether is also formed during this hydrocarbon synthesis on zeolite HZSM-5.

  1. Solid state amorphization of nanocrystalline nickel by cryogenic laser shock peening

    SciTech Connect

    Ye, Chang Ren, Zhencheng; Zhao, Jingyi; Hou, Xiaoning; Dong, Yalin; Liu, Yang; Sang, Xiahan

    2015-10-07

    In this study, complete solid state amorphization in nanocrystalline nickel has been achieved through cryogenic laser shock peening (CLSP). High resolution transmission electron microscopy has revealed the complete amorphous structure of the sample after CLSP processing. A molecular dynamic model has been used to investigate material behavior during the shock loading and the effects of nanoscale grain boundaries on the amorphization process. It has been found that the initial nanoscale grain boundaries increase the initial Gibbs free energy before plastic deformation and also serve as dislocation emission sources during plastic deformation to contribute to defect density increase, leading to the amorphization of pure nanocrystalline nickel.

  2. High-resolution color images of Io

    NASA Technical Reports Server (NTRS)

    Mcewen, A. S.; Soderblom, L. A.

    1984-01-01

    Color versions of the highest resolution Voyager images of Io were produced by combining the low resolution color images with the high resolution, clear filter images. High resolution versions of the orange, blue, and violet filter images are produced by: orange = high-res clear * low-res orange / low-res clear blue = high-res clear * low-res blue / low-res clear violet = high-res clear * low-res violet / low-res clear. The spectral responses of the high and low resolution clear filter images cancel, leaving the color, while the spatial frequencies of the two low resolution images cancel, leaving the high resolution.

  3. Solid state imagers and their applications; Proceedings of the Meeting, Cannes, France, November 26, 27, 1985

    NASA Technical Reports Server (NTRS)

    Declerck, Gilbert J. (Editor)

    1986-01-01

    Topics treated include the use of semiconductor imagers in high energy particle physics, an X-ray image sensor based on an optical TDI-CCD imager, and an electron-sensitive CCD readout array for a circular-scan streak tube. Papers are presented on the pan-imager, high resolution linear arrays, the reduction of reflection losses in solid-state image sensors, a high resolution CCD imager module with swing operation, large area CCD image sensors for scientific applications, and new readout techniques for frame transfer CCDs. Consideration is given to advanced optoelectronical sensors for autonomous rendezvous/docking and proximity operations in space, the testing and characterization of CCDs for the Rosat star sensors, an advanced radial camera for the Hubble Space Telescope, and scanning or staring infrared imagers.

  4. Zero-quantum stochastic dipolar recoupling in solid state nuclear magnetic resonance

    PubMed Central

    Qiang, Wei; Tycko, Robert

    2012-01-01

    We present the theoretical description and experimental demonstration of a zero-quantum stochastic dipolar recoupling (ZQ-SDR) technique for solid state nuclear magnetic resonance (NMR) studies of 13C-labeled molecules, including proteins, under magic-angle spinning (MAS). The ZQ-SDR technique combines zero-quantum recoupling pulse sequence blocks with randomly varying chemical shift precession periods to create randomly amplitude- and phase-modulated effective homonuclear magnetic dipole-dipole couplings. To a good approximation, couplings between different 13C spin pairs become uncorrelated under ZQ-SDR, leading to spin dynamics (averaged over many repetitions of the ZQ-SDR sequence) that are fully described by an orientation-dependent N × N polarization transfer rate matrix for an N-spin system, with rates that are inversely proportional to the sixth power of internuclear distances. Suppression of polarization transfers due to non-commutivity of pairwise couplings (i.e., dipolar truncation) does not occur under ZQ-SDR, as we show both analytically and numerically. Experimental demonstrations are reported for uniformly 13C-labeled L-valine powder (at 14.1 T and 28.00 kHz MAS), uniformly 13C-labeled protein GB1 in microcrystalline form (at 17.6 T and 40.00 kHz MAS), and partially labeled 13C-labeled protein GB1 (at 14.1 T and 40.00 kHz MAS). The experimental results verify that spin dynamics under ZQ-SDR are described accurately by rate matrices and suggest the utility of ZQ-SDR in structural studies of 13C-labeled solids. PMID:22979851

  5. Zero-quantum stochastic dipolar recoupling in solid state nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Qiang, Wei; Tycko, Robert

    2012-09-01

    We present the theoretical description and experimental demonstration of a zero-quantum stochastic dipolar recoupling (ZQ-SDR) technique for solid state nuclear magnetic resonance (NMR) studies of 13C-labeled molecules, including proteins, under magic-angle spinning (MAS). The ZQ-SDR technique combines zero-quantum recoupling pulse sequence blocks with randomly varying chemical shift precession periods to create randomly amplitude- and phase-modulated effective homonuclear magnetic dipole-dipole couplings. To a good approximation, couplings between different 13C spin pairs become uncorrelated under ZQ-SDR, leading to spin dynamics (averaged over many repetitions of the ZQ-SDR sequence) that are fully described by an orientation-dependent N × N polarization transfer rate matrix for an N-spin system, with rates that are inversely proportional to the sixth power of internuclear distances. Suppression of polarization transfers due to non-commutivity of pairwise couplings (i.e., dipolar truncation) does not occur under ZQ-SDR, as we show both analytically and numerically. Experimental demonstrations are reported for uniformly 13C-labeled L-valine powder (at 14.1 T and 28.00 kHz MAS), uniformly 13C-labeled protein GB1 in microcrystalline form (at 17.6 T and 40.00 kHz MAS), and partially labeled 13C-labeled protein GB1 (at 14.1 T and 40.00 kHz MAS). The experimental results verify that spin dynamics under ZQ-SDR are described accurately by rate matrices and suggest the utility of ZQ-SDR in structural studies of 13C-labeled solids.

  6. Effect of pressure on the carbon speciation in silicate glasses and melts: Insights from multi-nuclear solid-state NMR

    NASA Astrophysics Data System (ADS)

    Kim, E. J.; Fei, Y.; Lee, S. K.

    2015-12-01

    The pressure-induced structural changes in carbon-bearing silicate glasses and melts is essential to understand the changes in melt properties in the Earth interior and yield atomistic insights into the deep carbon cycle. Despite the extensive pioneering studies on carbon-bearing silicate glasses, spectroscopic and scattering studies at high pressure above ~4 GPa is limited due to the lack of suitable experimental probes. Here, we report the pressure-induced structural changes around C, Si and Al in albite and Na-trisilicate (Na2O:SiO2=1:3, NS3) glasses with varying pressure up to 8 GPa, using 27Al, 29Si and 13C solid-state high-resolution NMR. 27Al 3QMAS NMR spectra for carbon-bearing albite glasses quenched from melts at high pressure up to 6 GPa show only [4]Al environments. The FWHM of [4]Al in albite glasses increases with increasing pressure, indicating that the overall densification of albite glasses at high pressure is accompanied by an increase in the topological disorder around Al. 29Si MAS NMR spectra for NS3 glasses at high pressure up to 8 GPa show the presence of highly coordinated Si, [5,6]Si, which contributes to an increases in the total configurational disorder in the NS3 glasses with pressure. 13C MAS NMR spectra for carbon-bearing albite glasses show the presence of dominant fraction of CO2, and minor amounts of CO32-, and CO. At least three distinct carbonate species, such as [4]Si(CO3)[4]Si, [4]Si(CO3)[4]Al, and CO32- were observed. Among those species, the increase in the fraction of [4]Si(CO3)[4]Al species is most prevalent. 13C MAS NMR spectra for NS3 glasses show the presence of carbonate species. The peaks position of the carbonate species shifts to lower frequency upon compression, suggesting the pressure-induced structural distortion of CO32- in the glasses above 6 GPa. Spin-lattice (T1) relaxation time for molecular CO2 in carbon-bearing albite glasses increases with increasing pressure. T1 relaxation time for CO2 species at 6 GPa is 3

  7. Enhanced electrodes for solid state gas sensors

    DOEpatents

    Garzon, Fernando H.; Brosha, Eric L.

    2001-01-01

    A solid state gas sensor generates an electrical potential between an equilibrium electrode and a second electrode indicative of a gas to be sensed. A solid electrolyte substrate has the second electrode mounted on a first portion of the electrolyte substrate and a composite equilibrium electrode including conterminous transition metal oxide and Pt components mounted on a second portion of the electrolyte substrate. The composite equilibrium electrode and the second electrode are electrically connected to generate an electrical potential indicative of the gas that is being sensed. In a particular embodiment of the present invention, the second electrode is a reference electrode that is exposed to a reference oxygen gas mixture so that the electrical potential is indicative of the oxygen in a gas stream.

  8. An active solid state ring laser gyroscope

    SciTech Connect

    Valle, T.J.

    1992-01-01

    The properties of an active, solid state ring laser gyroscope were investigated. Two laser diode pumped monolithic nonplanar ring oscillators (NPRO), forced to lase in opposite directions, formed the NPRO-Gyro. It was unique in being an active ring laser gyroscope with a homogeneously broadened gain medium. This work examined sources of technical and fundamental noise. Associated calculations accounted for aspects of the NPRO-Gyro performance, suggested design improvements, and outlined limitations. The work brought out the need to stabilize the NPRO environment in order to achieve performance goals. Two Nd:YAG NPROs were mounted within an environment short term stabilized to microdegrees Celsius. The Allan variance of the NPRO-Gyro beat note was 500 Hz for a one second time delay. Unequal treatment of the NPROs appeared as noise on the beat frequency, therefore reducing its rotation sensitivity. The sensitivity to rotation was limited by technical noise sources.

  9. Compact high voltage solid state switch

    DOEpatents

    Glidden, Steven C.

    2003-09-23

    A compact, solid state, high voltage switch capable of high conduction current with a high rate of current risetime (high di/dt) that can be used to replace thyratrons in existing and new applications. The switch has multiple thyristors packaged in a single enclosure. Each thyristor has its own gate drive circuit that circuit obtains its energy from the energy that is being switched in the main circuit. The gate drives are triggered with a low voltage, low current pulse isolated by a small inexpensive transformer. The gate circuits can also be triggered with an optical signal, eliminating the trigger transformer altogether. This approach makes it easier to connect many thyristors in series to obtain the hold off voltages of greater than 80 kV.

  10. Supramolecular interactions in the solid state

    PubMed Central

    Resnati, Giuseppe; Boldyreva, Elena; Bombicz, Petra; Kawano, Masaki

    2015-01-01

    In the last few decades, supramolecular chemistry has been at the forefront of chemical research, with the aim of understanding chemistry beyond the covalent bond. Since the long-range periodicity in crystals is a product of the directionally specific short-range intermolecular interactions that are responsible for molecular assembly, analysis of crystalline solids provides a primary means to investigate intermolecular interactions and recognition phenomena. This article discusses some areas of contemporary research involving supramolecular interactions in the solid state. The topics covered are: (1) an overview and historical review of halogen bonding; (2) exploring non-ambient conditions to investigate intermolecular interactions in crystals; (3) the role of intermolecular interactions in morphotropy, being the link between isostructurality and polymorphism; (4) strategic realisation of kinetic coordination polymers by exploiting multi-interactive linker molecules. The discussion touches upon many of the prerequisites for controlled preparation and characterization of crystalline materials. PMID:26594375

  11. Solid state potentiometric gaseous oxide sensor

    NASA Technical Reports Server (NTRS)

    Wachsman, Eric D. (Inventor); Azad, Abdul Majeed (Inventor)

    2003-01-01

    A solid state electrochemical cell (10a) for measuring the concentration of a component of a gas mixture (12) includes first semiconductor electrode (14) and second semiconductor electrode (16) formed from first and second semiconductor materials, respectively. The materials are selected so as to undergo a change in resistivity upon contacting a gas component, such as CO or NO. An electrolyte (18) is provided in contact with the first and second semiconductor electrodes. A reference cell can be included in contact with the electrolyte. Preferably, a voltage response of the first semiconductor electrode is opposite in slope direction to that of the second semiconductor electrode to produce a voltage response equal to the sum of the absolute values of the control system uses measured pollutant concentrations to direct adjustment of engine combustion conditions.

  12. Solid-state spectral transmissometer and radiometer

    NASA Technical Reports Server (NTRS)

    Carder, K. L.; Steward, R. G.; Payne, P. R.

    1985-01-01

    An in situ instrument designed to measure the spectral attenuation coefficient of seawater and the ocean remote-sensing reflectance from 400 to 750 nm is in the test and development stage. It employs a 256 channel, charge-coupled type of linear array measuring the spectral intensities diffracted by a grating. Examples of the types of data delivered by this instrument have been simulated using a breadboard laboratory instrument and an above-water, solid-state radiometer. Algorithms developed using data from these instruments provide measures of chlorophyll a plus phaeophytin a concentrations from less than 0.1 to 77.0 mg/cu m, gelbstoff spectral absorption coefficients, and detrital spectral backscattering coefficients for waters of the west Florida shelf.

  13. Solid state neutron dosimeter for space applications

    SciTech Connect

    Nagarkar, V.; Entine, G.; Stoppel, P.; Cirignano, L. ); Swinehart, P. )

    1992-08-01

    One of the most important contributions to the radiation exposure of astronauts engaged in space flight is the significant flux of high energy neutrons arising from both primary and secondary sources of ionizing radiation. Under NASA sponsorship, the authors are developing a solid state neutron sensor capable of being incorporated into a very compact, flight instrument to provide high quality real time measurement of this important radiation flux. The dosimeter uses a special, high neutron sensitivity, PIN diode that is insensitive t the other forms of ionizing radiation. The dosimeter will have the ability to measure and record neutron dose over a range of 50 microgray to tens of milligrays (5 millirads to several rads) over a flight of up to 30 days. the performance characteristics of the PIN diode with a detailed description of the overall dosimeter is presented. in this paper.

  14. Electronically shielded solid state charged particle detector

    DOEpatents

    Balmer, D.K.; Haverty, T.W.; Nordin, C.W.; Tyree, W.H.

    1996-08-20

    An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite. 1 fig.

  15. A solid state lightning propagation speed sensor

    NASA Technical Reports Server (NTRS)

    Mach, Douglas M.; Rust, W. David

    1989-01-01

    A device to measure the propagation speeds of cloud-to-ground lightning has been developed. The lightning propagation speed (LPS) device consists of eight solid state silicon photodetectors mounted behind precision horizontal slits in the focal plane of a 50-mm lens on a 35-mm camera. Although the LPS device produces results similar to those obtained from a streaking camera, the LPS device has the advantages of smaller size, lower cost, mobile use, and easier data collection and analysis. The maximum accuracy for the LPS is 0.2 microsec, compared with about 0.8 microsecs for the streaking camera. It is found that the return stroke propagation speed for triggered lightning is different than that for natural lightning if measurements are taken over channel segments less than 500 m. It is suggested that there are no significant differences between the propagation speeds of positive and negative flashes. Also, differences between natural and triggered dart leaders are discussed.

  16. Electronically shielded solid state charged particle detector

    DOEpatents

    Balmer, David K.; Haverty, Thomas W.; Nordin, Carl W.; Tyree, William H.

    1996-08-20

    An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite.

  17. Nuclear-driven solid-state lasers

    NASA Astrophysics Data System (ADS)

    Prelas, Mark A.

    A total system efficiency of 3 percent is calculated for very high average power active mirror solid-state laser amplifiers of co-doped material, such as Nd:Cr:GSGG, pumped by visible nuclear-driven alkali metal excimer fluorescence. The fluorescence is transported around a radiation shield, separating the fluorescer and the laser, by a large diameter-to-length ratio hollow lightpipe. Parameters for a system with peak power of 6 MW for 1 ms pulse at 1 Hz for an average power output of 6 kW are presented. This type of system would require the development of a small 200-kW thermal nuclear reactor (similar in size to small university research reactors). A much larger system can be developed as well.

  18. Dual mode solid state power switch

    NASA Technical Reports Server (NTRS)

    Maus, Louis C. (Inventor); Williams, Donald E. (Inventor)

    1976-01-01

    A solid state amplifier has an output transistor stage and an input transistor stage interconnected as a Darlington circuit. An interstage transistor interconnecting the collectors of the two stages of the Darlington circuit is connected with the first stage transistor in a compound configuration. When the load current furnished by the amplifier is less than a predetermined value, the output stage operates as a simple saturated switch with its base drive current flowing through the emitter-base junction of the first stage which produces no collector current because the base-emitter junction of the interstage transistor is reverse-biased. When the load current exceeds said predetermined value, the interstage transistor begins to conduct allowing the input and output stages to operate as a Darlington amplifier and diverting a significant portion of the base drive current of the output transistor back into the load.

  19. Efficient scalable solid-state neutron detector.

    PubMed

    Moses, Daniel

    2015-06-01

    We report on scalable solid-state neutron detector system that is specifically designed to yield high thermal neutron detection sensitivity. The basic detector unit in this system is made of a (6)Li foil coupled to two crystalline silicon diodes. The theoretical intrinsic efficiency of a detector-unit is 23.8% and that of detector element comprising a stack of five detector-units is 60%. Based on the measured performance of this detector-unit, the performance of a detector system comprising a planar array of detector elements, scaled to encompass effective area of 0.43 m(2), is estimated to yield the minimum absolute efficiency required of radiological portal monitors used in homeland security. PMID:26133869

  20. Solid-state single-photon emitters

    NASA Astrophysics Data System (ADS)

    Aharonovich, Igor; Englund, Dirk; Toth, Milos

    2016-10-01

    Single-photon emitters play an important role in many leading quantum technologies. There is still no 'ideal' on-demand single-photon emitter, but a plethora of promising material systems have been developed, and several have transitioned from proof-of-concept to engineering efforts with steadily improving performance. Here, we review recent progress in the race towards true single-photon emitters required for a range of quantum information processing applications. We focus on solid-state systems including quantum dots, defects in solids, two-dimensional hosts and carbon nanotubes, as these are well positioned to benefit from recent breakthroughs in nanofabrication and materials growth techniques. We consider the main challenges and key advantages of each platform, with a focus on scalable on-chip integration and fabrication of identical sources on photonic circuits.

  1. Efficient scalable solid-state neutron detector

    SciTech Connect

    Moses, Daniel

    2015-06-15

    We report on scalable solid-state neutron detector system that is specifically designed to yield high thermal neutron detection sensitivity. The basic detector unit in this system is made of a {sup 6}Li foil coupled to two crystalline silicon diodes. The theoretical intrinsic efficiency of a detector-unit is 23.8% and that of detector element comprising a stack of five detector-units is 60%. Based on the measured performance of this detector-unit, the performance of a detector system comprising a planar array of detector elements, scaled to encompass effective area of 0.43 m{sup 2}, is estimated to yield the minimum absolute efficiency required of radiological portal monitors used in homeland security.

  2. Solid-state curved focal plane arrays

    NASA Technical Reports Server (NTRS)

    Nikzad, Shouleh (Inventor); Hoenk, Michael (Inventor); Jones, Todd (Inventor)

    2010-01-01

    The present invention relates to curved focal plane arrays. More specifically, the present invention relates to a system and method for making solid-state curved focal plane arrays from standard and high-purity devices that may be matched to a given optical system. There are two ways to make a curved focal plane arrays starting with the fully fabricated device. One way, is to thin the device and conform it to a curvature. A second way, is to back-illuminate a thick device without making a thinned membrane. The thick device is a special class of devices; for example devices fabricated with high purity silicon. One surface of the device (the non VLSI fabricated surface, also referred to as the back surface) can be polished to form a curved surface.

  3. Solid-state ring laser gyroscope

    NASA Astrophysics Data System (ADS)

    Schwartz, S.

    The ring laser gyroscope is a rotation sensor used in most kinds of inertial navigation units. It usually consists in a ring cavity filled with a mixture of helium and neon, together with high-voltage pumping electrodes. The use of a gaseous gain medium, while resulting naturally in a stable bidirectional regime enabling rotation sensing, is however the main industrially limiting factor for the ring laser gyroscopes in terms of cost, reliability and lifetime. We study in this book the possibility of substituting for the gaseous gain medium a solid-state medium (diode-pumped Nd-YAG). For this, a theoretical and experimental overview of the lasing regimes of the solid-state ring laser is reported. We show that the bidirectional emission can be obtained thanks to a feedback loop acting on the states of polarization and inducing differential losses proportional to the difference of intensity between the counterpropagating modes. This leads to the achievement of a solid-state ring laser gyroscope, whose frequency response is modified by mode coupling effects. Several configurations, either mechanically or optically based, are then successively studied, with a view to improving the quality of this frequency response. In particular, vibration of the gain crystal along the longitudinal axis appears to be a very promising technique for reaching high inertial performances with a solid-state ring laser gyroscope. Gyrolaser à état solide. Le gyrolaser est un capteur de rotation utilisé dans la plupart des centrales de navigation inertielle. Dans sa forme usuelle, il est constitué d'une cavité laser en anneau remplie d'un mélange d'hélium et de néon pompé par des électrodes à haute tension. L'utilisation d'un milieu amplificateur gazeux, si elle permet de garantir naturellement le fonctionnement bidirectionnel stable nécessaire à la mesure des rotations, constitue en revanche la principale limitation industrielle des gyrolasers actuels en termes de coût, fiabilit

  4. Efficient scalable solid-state neutron detector

    NASA Astrophysics Data System (ADS)

    Moses, Daniel

    2015-06-01

    We report on scalable solid-state neutron detector system that is specifically designed to yield high thermal neutron detection sensitivity. The basic detector unit in this system is made of a 6Li foil coupled to two crystalline silicon diodes. The theoretical intrinsic efficiency of a detector-unit is 23.8% and that of detector element comprising a stack of five detector-units is 60%. Based on the measured performance of this detector-unit, the performance of a detector system comprising a planar array of detector elements, scaled to encompass effective area of 0.43 m2, is estimated to yield the minimum absolute efficiency required of radiological portal monitors used in homeland security.

  5. Solid-state lighting technology perspective.

    SciTech Connect

    Tsao, Jeffrey Yeenien; Coltrin, Michael Elliott

    2006-08-01

    Solid-State Lighting (SSL) uses inorganic light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs) to convert electricity into light for illumination. SSL has the potential for enormous energy savings and accompanying environmental benefits if its promise of 50% (or greater) energy efficiencies can be achieved. This report provides a broad summary of the technologies that underlie SSL. The applications for SSL and potential impact on U.S. and world-wide energy consumption, and impact on the human visual experience are discussed. The properties of visible light and different technical metrics to characterize its properties are summarized. The many factors contributing to the capital and operating costs for SSL and traditional lighting sources (incandescent, fluorescent, and high-intensity discharge lamps) are discussed, with extrapolations for future SSL goals. The technologies underlying LEDs and OLEDs are also described, including current and possible alternative future technologies and some of the present limitations.

  6. Supramolecular interactions in the solid state.

    PubMed

    Resnati, Giuseppe; Boldyreva, Elena; Bombicz, Petra; Kawano, Masaki

    2015-11-01

    In the last few decades, supramolecular chemistry has been at the forefront of chemical research, with the aim of understanding chemistry beyond the covalent bond. Since the long-range periodicity in crystals is a product of the directionally specific short-range intermolecular interactions that are responsible for molecular assembly, analysis of crystalline solids provides a primary means to investigate intermolecular interactions and recognition phenomena. This article discusses some areas of contemporary research involving supramolecular interactions in the solid state. The topics covered are: (1) an overview and historical review of halogen bonding; (2) exploring non-ambient conditions to investigate intermolecular interactions in crystals; (3) the role of intermolecular interactions in morphotropy, being the link between isostructurality and polymorphism; (4) strategic realisation of kinetic coordination polymers by exploiting multi-interactive linker molecules. The discussion touches upon many of the prerequisites for controlled preparation and characterization of crystalline materials.

  7. Solid state dye laser for medical applications

    NASA Astrophysics Data System (ADS)

    Aldag, Henry R.

    1994-06-01

    The development of solid state dye lasers could lead to a major breakthrough in the cost and compactness of a medical device. Advantages include: elimination of the flow system for the gain medium; ease with which to implement wavelength agility or the replacement of a degraded rod or sheet; and toxicity and flammability become a non-issue. Dye lasers have played a role in cardiology, dermatology, and urology. Of these cardiology is of interest to Palomar. The Palomar Model 3010 flashlamp-pumped dye laser medical device was used during phase 1 FDA clinical trials to break-up blood clots that cause heart attacks, a process known as coronary laser thrombolysis. It is the objective of this research and development effort to produce solid matrix lasers that will replace liquid dye lasers in these medical specialties.

  8. High-efficiency solid state power amplifier

    NASA Technical Reports Server (NTRS)

    Wallis, Robert E. (Inventor); Cheng, Sheng (Inventor)

    2005-01-01

    A high-efficiency solid state power amplifier (SSPA) for specific use in a spacecraft is provided. The SSPA has a mass of less than 850 g and includes two different X-band power amplifier sections, i.e., a lumped power amplifier with a single 11-W output and a distributed power amplifier with eight 2.75-W outputs. These two amplifier sections provide output power that is scalable from 11 to 15 watts without major design changes. Five different hybrid microcircuits, including high-efficiency Heterostructure Field Effect Transistor (HFET) amplifiers and Monolithic Microwave Integrated Circuit (MMIC) phase shifters have been developed for use within the SSPA. A highly efficient packaging approach enables the integration of a large number of hybrid circuits into the SSPA.

  9. Solid-State Spectral Light Source System

    NASA Technical Reports Server (NTRS)

    Maffione, Robert; Dana, David

    2011-01-01

    A solid-state light source combines an array of light-emitting diodes (LEDs) with advanced electronic control and stabilization over both the spectrum and overall level of the light output. The use of LEDs provides efficient operation over a wide range of wavelengths and power levels, while electronic control permits extremely stable output and dynamic control over the output. In this innovation, LEDs are used instead of incandescent bulbs. Optical feedback and digital control are used to monitor and regulate the output of each LED. Because individual LEDs generate light within narrower ranges of wavelengths than incandescent bulbs, multiple LEDs are combined to provide a broad, continuous spectrum, or to produce light within discrete wavebands that are suitable for specific radiometric sensors.

  10. 13C isotopic fractionation during biodegradation of agricultural wastes.

    PubMed

    Chalk, Phillip M; Inácio, Caio T; Urquiaga, Segundo; Chen, Deli

    2015-01-01

    Significant differences in δ(13)C signatures occur within and between plant tissues and their constituent biochemical entities, and also within and between heterotrophic bacteria and fungi and their metabolic products. Furthermore, (13)C isotopic fractionation occurs during the biodegradation of organic molecules as seen in the substrate, respired CO(2) and the microbial biomass, which could be related to substrate composition and/or microbial metabolism. The (13)C isotopic fractionation observed during the decomposition of a single defined C substrate appears to be due to the intra-molecular heterogeneity in (13)C in the substrate and to (13)C isotopic fractionation during microbial metabolism. Very limited data suggest that the latter may be quantitatively more important than the former. Studies with defined fungi in culture media have highlighted the complexities associated with the interpretation of the observed patterns of (13)C isotopic fractionation when a single defined C source is added to the culture medium which itself contains one or more C sources. Techniques involving (13)C enrichment or paired treatments involving an equivalent C(3)- and C(4)-derived substrate have been devised to overcome the problem of background C in the culture medium and (13)C isotopic fractionation during metabolism. Studies with complex substrates have shown an initial (13)C depletion phase in respired CO(2) followed by a (13)C enrichment phase which may or may not be followed by another (13)C depletion phase. Basic studies involving an integrated approach are required to gain a new insight into (13)C isotopic fractionation during organic residue decomposition, by simultaneous measurements of δ(13)C in all C moieties. New analytical tools to measure real-time changes in δ(13)CO(2) and the intra-molecular δ(13)C distribution within plant biochemical entities offer new opportunities for unravelling the complex interactions between substrate and microbial metabolism with

  11. 13CFLUX2—high-performance software suite for 13C-metabolic flux analysis

    PubMed Central

    Weitzel, Michael; Nöh, Katharina; Dalman, Tolga; Niedenführ, Sebastian; Stute, Birgit; Wiechert, Wolfgang

    2013-01-01

    Summary: 13C-based metabolic flux analysis (13C-MFA) is the state-of-the-art method to quantitatively determine in vivo metabolic reaction rates in microorganisms. 13CFLUX2 contains all tools for composing flexible computational 13C-MFA workflows to design and evaluate carbon labeling experiments. A specially developed XML language, FluxML, highly efficient data structures and simulation algorithms achieve a maximum of performance and effectiveness. Support of multicore CPUs, as well as compute clusters, enables scalable investigations. 13CFLUX2 outperforms existing tools in terms of universality, flexibility and built-in features. Therewith, 13CFLUX2 paves the way for next-generation high-resolution 13C-MFA applications on the large scale. Availability and implementation: 13CFLUX2 is implemented in C++ (ISO/IEC 14882 standard) with Java and Python add-ons to run under Linux/Unix. A demo version and binaries are available at www.13cflux.net. Contact: info@13cflux.net or k.noeh@fz-juelich.de Supplementary information: Supplementary data are available at Bioinformatics online. PMID:23110970

  12. In vivo 13C NMR metabolite profiling: potential for understanding and assessing conifer seed quality.

    PubMed

    Terskikh, Victor V; Feurtado, J Allan; Borchardt, Shane; Giblin, Michael; Abrams, Suzanne R; Kermode, Allison R

    2005-08-01

    High-resolution 13C MAS NMR spectroscopy was used to profile a range of primary and secondary metabolites in vivo in intact whole seeds of eight different conifer species native to North America, including six of the Pinaceae family and two of the Cupressaceae family. In vivo 13C NMR provided information on the total seed oil content and fatty acid composition of the major storage lipids in a non-destructive manner. In addition, a number of monoterpenes were identified in the 13C NMR spectra of conifer seeds containing oleoresin; these compounds showed marked variability in individual seeds of Pacific silver fir within the same seed lot. In imbibed conifer seeds, the 13C NMR spectra showed the presence of considerable amounts of dissolved sucrose presumed to play a protective role in the desiccation-tolerance of seeds. The free amino acids arginine and asparagine, generated as a result of storage protein mobilization, were detected in vivo during seed germination and early seedling growth. The potential for NMR to profile metabolites in a non-destructive manner in single conifer seeds and seed populations is discussed. It is a powerful tool to evaluate seed quality because of its ability to assess reserve accumulation during seed development or at seed maturity; it can also be used to monitor reserve mobilization, which is critical for seedling emergence. PMID:15996983

  13. Solid-state NMR studies of supercapacitors.

    PubMed

    Griffin, John M; Forse, Alexander C; Grey, Clare P

    2016-01-01

    Electrochemical double-layer capacitors, or 'supercapacitors' are attracting increasing attention as high-power energy storage devices for a wide range of technological applications. These devices store charge through electrostatic interactions between liquid electrolyte ions and the surfaces of porous carbon electrodes. However, many aspects of the fundamental mechanism of supercapacitance are still not well understood, and there is a lack of experimental techniques which are capable of studying working devices. Recently, solid-state NMR has emerged as a powerful tool for studying the local environments and behaviour of electrolyte ions in supercapacitor electrodes. In this Trends article, we review these recent developments and applications. We first discuss the basic principles underlying the mechanism of supercapacitance, as well as the key NMR observables that are relevant to the study of supercapacitor electrodes. We then review some practical aspects of the study of working devices using ex situ and in situ methodologies and explain the key advances that these techniques have allowed on the study of supercapacitor charging mechanisms. NMR experiments have revealed that the pores of the carbon electrodes contain a significant number of electrolyte ions in the absence of any charging potential. This has important implications for the molecular mechanisms of supercapacitance, as charge can be stored by different ion adsorption/desorption processes. Crucially, we show how in situ NMR experiments can be used to quantitatively study and characterise the charging mechanism, with the experiments providing the most detailed picture of charge storage to date, offering the opportunity to design enhanced devices. Finally, an outlook for future directions for solid-state NMR in supercapacitor research is offered. PMID:26974032

  14. Solid-state NMR studies of supercapacitors.

    PubMed

    Griffin, John M; Forse, Alexander C; Grey, Clare P

    2016-01-01

    Electrochemical double-layer capacitors, or 'supercapacitors' are attracting increasing attention as high-power energy storage devices for a wide range of technological applications. These devices store charge through electrostatic interactions between liquid electrolyte ions and the surfaces of porous carbon electrodes. However, many aspects of the fundamental mechanism of supercapacitance are still not well understood, and there is a lack of experimental techniques which are capable of studying working devices. Recently, solid-state NMR has emerged as a powerful tool for studying the local environments and behaviour of electrolyte ions in supercapacitor electrodes. In this Trends article, we review these recent developments and applications. We first discuss the basic principles underlying the mechanism of supercapacitance, as well as the key NMR observables that are relevant to the study of supercapacitor electrodes. We then review some practical aspects of the study of working devices using ex situ and in situ methodologies and explain the key advances that these techniques have allowed on the study of supercapacitor charging mechanisms. NMR experiments have revealed that the pores of the carbon electrodes contain a significant number of electrolyte ions in the absence of any charging potential. This has important implications for the molecular mechanisms of supercapacitance, as charge can be stored by different ion adsorption/desorption processes. Crucially, we show how in situ NMR experiments can be used to quantitatively study and characterise the charging mechanism, with the experiments providing the most detailed picture of charge storage to date, offering the opportunity to design enhanced devices. Finally, an outlook for future directions for solid-state NMR in supercapacitor research is offered.

  15. NOAA's Use of High-Resolution Imagery

    NASA Technical Reports Server (NTRS)

    Hund, Erik

    2007-01-01

    NOAA's use of high-resolution imagery consists of: a) Shoreline mapping and nautical chart revision; b) Coastal land cover mapping; c) Benthic habitat mapping; d) Disaster response; and e) Imagery collection and support for coastal programs.

  16. [Characterization of biochar by X-ray photoelectron spectroscopy and 13C nuclear magnetic resonance].

    PubMed

    Xu, Dong-yu; Jin, Jie; Yan, Yu; Han, Lan-fang; Kang, Ming-jie; Wang, Zi-ying; Zhao, Ye; Sun, Ke

    2014-12-01

    The wood (willow branch) and grass (rice straw) materials were pyrolyzed at different temperatures (300, 450 and 600 °C) to obtain the biochars used in the present study. The biochars were characterized using elementary analysis, X-ray photoelectron spectroscopy (XPS) and solid state 13C cross-polarization and magic angle spinning nuclear magnetic resonance spectroscopy (13C NMR) to illuminate the structure and composition of the biochars which were derived from the different thermal temperatures and biomass. The results showed that the H/C, O/C and (O+N)/C ratios of the biochars decreased with the increase in the pyrolysis temperatures. The surface polarity and ash content of the grass-derived biochars were higher than those of the wood-derived biochars. The minerals of the wood-derived biochars were mainly covered by the organic matter; in contrast, parts of the mineral surfaces of the grass-derived biochars were not covered by organic matter? The 13C NMR of the low temperature-derived biochars revealed a large contribution of aromatic carbon, aliphatic carbon, carboxyl and carbonyl carbon, while the high temperature-derived biochars contained a large amount of aromatic carbon. Moreover, the wood-derived biochars produced at low heat treatment temperatures contained more lignin residues than grass-derived ones, probably due to the existence of high lignin content in the feedstock soures of wood-derived biochars. The results of the study would be useful for environmental application of biochars.

  17. High-resolution 2D NMR spectroscopy of bicelles to measure the membrane interaction of ligands.

    PubMed

    Dvinskikh, Sergey V; Dürr, Ulrich H N; Yamamoto, Kazutoshi; Ramamoorthy, Ayyalusamy

    2007-01-31

    Magnetically aligned bicelles are increasingly being used as model membranes in solution- and solid-state NMR studies of the structure, dynamics, topology, and interaction of membrane-associated peptides and proteins. These studies commonly utilize the PISEMA pulse sequence to measure dipolar coupling and chemical shift, the two key parameters used in subsequent structural analysis. In the present study, we demonstrate that the PISEMA and other rotating-frame pulse sequences are not suitable for the measurement of long-range heteronuclear dipolar couplings, and that they provide inaccurate values when multiple protons are coupled to a 13C nucleus. Furthermore, we demonstrate that a laboratory-frame separated-local-field experiment is capable of overcoming these difficulties in magnetically aligned bicelles. An extension of this approach to accurately measure 13C-31P and 1H-31P couplings from phospholipids, which are useful to understand the interaction of molecules with the membrane, is also described. In these 2D experiments, natural abundance 13C was observed from bicelles containing DMPC and DHPC lipid molecules. As a first application, these solid-state NMR approaches were utilized to probe the membrane interaction of an antidepressant molecule, desipramine, and its location in the membrane.

  18. Complete (1)H and (13)C signal assignment of prenol-10 with 3D NMR spectroscopy.

    PubMed

    Misiak, Maria; Koźmiński, Wiktor; Kwasiborska, Maria; Wójcik, Jacek; Ciepichal, Ewa; Swiezewska, Ewa

    2009-10-01

    The complete assignment of (1)H and (13)C chemical shifts of natural abundance prenol-10 is reported for the first time. It was achieved using 3D NMR experiments, which were based on random sampling of the evolution time space followed by multidimensional Fourier transform. This approach makes it possible to acquire 3D NMR spectra in a reasonable time and preserves high resolution in indirectly detected dimensions. It is shown that the interpretation of 3D COSY-HMBC and 3D TOCSY-HSQC spectra is crucial in the structural analysis of prenol-10.

  19. Arabidopsis thalianafrom Polarization Transfer Solid-State NMR

    SciTech Connect

    White, Paul B; Wang, Tuo; Park, Yong Bum; Cosgrove, Daniel J; Hong, Mei

    2014-07-23

    Polysaccharide-rich plant cell walls are hydrated under functional conditions, but the molecular interactions between water and polysaccharides in the wall have not been investigated. In this work, we employ polarization transfer solid-state NMR techniques to study the hydration of primary-wall polysaccharides of the model plant, Arabidopsis thaliana. By transferring water 1H polarization to polysaccharides through distance- and mobility-dependent 1H–1H dipolar couplings and detecting it through polysaccharide 13C signals, we obtain information about water proximity to cellulose, hemicellulose, and pectins as well as water mobility. Both intact and partially extracted cell wall samples are studied. Our results show that water–pectin polarization transfer is much faster than water–cellulose polarization transfer in all samples, but the extent of extraction has a profound impact on the water–polysaccharide spin diffusion. Removal of calcium ions and the consequent extraction of homogalacturonan (HG) significantly slowed down spin diffusion, while further extraction of matrix polysaccharides restored the spin diffusion rate. These trends are observed in cell walls with similar water content, thus they reflect inherent differences in the mobility and spatial distribution of water. Combined with quantitative analysis of the polysaccharide contents, our results indicate that calcium ions and HG gelation increase the amount of bound water, which facilitates spin diffusion, while calcium removal disrupts the gel and gives rise to highly dynamic water, which slows down spin diffusion. The recovery of spin diffusion rates after more extensive extraction is attributed to increased water-exposed surface areas of the polysaccharides. Water–pectin spin diffusion precedes water–cellulose spin diffusion, lending support to the single-network model of plant primary walls in which a substantial fraction of the cellulose surface is surrounded by pectins.

  20. Polymorphs of Theophylline Characterized by DNP Enhanced Solid-State NMR

    PubMed Central

    2015-01-01

    We show how dynamic nuclear polarization (DNP) enhanced solid-state NMR spectroscopy can be used to characterize polymorphs and solvates of organic solids. We applied DNP to three polymorphs and one hydrated form of the asthma drug molecule theophylline. For some forms of theophylline, sample grinding and impregnation with the radical-containing solution, which are necessary to prepare the samples for DNP, were found to induce polymorphic transitions or desolvation between some forms. We present protocols for sample preparation for solid-state magic-angle spinning (MAS) DNP experiments that avoid the polymorphic phase transitions in theophylline. These protocols include cryogrinding, grinding under inert atmosphere, and the appropriate choice of the impregnating liquid. By applying these procedures, we subsequently demonstrate that two-dimensional correlation experiments, such as 1H–13C and 1H–15N HETCOR or 13C–13C INADEQUATE, can be obtained at natural isotopic abundance in reasonable times, thus enabling more advanced structural characterization of polymorphs. PMID:26393368