WorldWideScience

Sample records for 13c nuclear magnetic

  1. (13C-(13c homonuclear recoupling in solid-state nuclear magnetic resonance at a moderately high magic-angle-spinning frequency.

    Directory of Open Access Journals (Sweden)

    Venus Singh Mithu

    Full Text Available Two-dimensional (13C-(13C correlation experiments are widely employed in structure determination of protein assemblies using solid-state nuclear magnetic resonance. Here, we investigate the process of (13C-(13C 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 (1H channel on the magnetisation transfer efficiency of these schemes is discussed in detail.

  2. 13C-13C Homonuclear Recoupling in Solid-State Nuclear Magnetic Resonance at a Moderately High Magic-Angle-Spinning Frequency

    Science.gov (United States)

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

    2013-01-01

    Two-dimensional 13C-13C correlation experiments are widely employed in structure determination of protein assemblies using solid-state nuclear magnetic resonance. Here, we investigate the process of 13C-13C 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 1H channel on the magnetisation transfer efficiency of these schemes is discussed in detail. PMID:23326308

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

    Science.gov (United States)

    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.

  4. Adult-onset hypothyroidism and the cerebral metabolism of (1,2-13C2) acetate as detected by 13C nuclear magnetic resonance.

    Science.gov (United States)

    Chapa, F; Künnecke, B; Calvo, R; Escobar del Rey, F; Morreale de Escobar, G; Cerdán, S

    1995-01-01

    The effects of adult-onset hypothyroidism on the metabolic compartmentation of the cerebral tricarboxylic acid cycle and the gamma-aminobutyric acid (GABA) shunt have been investigated by 13C nuclear magnetic resonance spectroscopy. Rats thyroidectomized as adults and age-matched controls were infused in the right jugular vein with unlabeled or (1,2-13C2) acetate solutions for 60 min. At the end of the infusion, the brains were frozen in situ and perchloric acid extracts were prepared and analyzed by 13C nuclear magnetic resonance and reverse-phase HPLC. Thyroidectomized animals showed a decrease in the incorporation of 13C from (1,2-13C2) acetate in cerebral metabolites and an increase in the concentrations of unlabeled glutamate and GABA. Computer-assisted interpretation of the 13C multiplets observed for the carbons of glutamate, glutamine, and GABA indicated that adult-onset hypothyroidism produced 1) a decrease in the contribution of infused (1,2-13C2) acetate to the glial tricarboxylic acid cycle; 2) an increase in the contribution of unlabeled acetyl-CoA to the neuronal tricarboxylic acid cycle; and 3) impairments in the exchange of glutamate, glutamine, and GABA between the neuronal and glial compartments. Despite the fact that the adult brain has often been considered metabolically unresponsive to thyroid hormone status, present results show metabolic alterations in the neuronal and glial compartments that are reversible with substitution therapy.

  5. [Characterization of biochar by X-ray photoelectron spectroscopy and 13C nuclear magnetic resonance].

    Science.gov (United States)

    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.

  6. T1 nuclear magnetic relaxation dispersion of hyperpolarized sodium and cesium hydrogencarbonate-(13) C.

    Science.gov (United States)

    Martínez-Santiesteban, Francisco M; Dang, Thien Phuoc; Lim, Heeseung; Chen, Albert P; Scholl, Timothy J

    2017-09-01

    In vivo pH mapping in tissue using hyperpolarized hydrogencarbonate-(13) C has been proposed as a method to study tumor growth and treatment and other pathological conditions related to pH changes. The finite spin-lattice relaxation times (T1 ) of hyperpolarized media are a significant limiting factor for in vivo imaging. Relaxation times can be measured at standard magnetic fields (1.5 T, 3.0 T etc.), but no such data are available at low fields, where T1 values can be significantly shorter. This information is required to determine the potential loss of polarization as the agent is dispensed and transported from the polarizer to the MRI scanner. The purpose of this study is to measure T1 dispersion from low to clinical magnetic fields (0.4 mT to 3.0 T) of different hyperpolarized hydrogencarbonate formulations previously proposed in the literature for in vivo pH measurements. (13) C-enriched cesium and sodium hydrogencarbonate preparations were hyperpolarized using dynamic nuclear polarization, and the T1 values of different samples were measured at different magnetic field strengths using a fast field-cycling relaxometer and a 3.0 T clinical MRI system. The effects of deuterium oxide as a dissolution medium for sodium hydrogencarbonate were also analyzed. This study finds that the cesium formulation has slightly shorter T1 values compared with the sodium preparation. However, the higher solubility of cesium hydrogencarbonate-(13) C means it can be polarized at greater concentration, using less trityl radical than sodium hydrogencarbonate-(13) C. This study also establishes that the preparation and handling of sodium hydrogencarbonate formulations in relation to cesium hydrogencarbonate is more difficult, due to the higher viscosity and lower achievable concentrations, and that deuterium oxide significantly increases the T1 of sodium hydrogencarbonate solutions. Finally, this work also investigates the influence of pH on the spin-lattice relaxation of cesium

  7. Methylamine metabolism in Hansenula polymorpha: an in vivo 13C and 31P nuclear magnetic resonance study.

    OpenAIRE

    Jones, J G; Bellion, E

    1991-01-01

    Methylamine uptake, oxidation, and assimilation were studied in Hansenula polymorpha, a methylotrophic yeast. The constitutive ammonia transport system was shown to be effective at accumulating methylamine within cells cultured with methylamine or ammonia as a nitrogen source. [13C]methylamine oxidation rates were measured in vivo in methylamine-adapted cells by 13C nuclear magnetic resonance and were found to be lower than its uptake rate into the cells. The 13C label of methylamine was foun...

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

    Science.gov (United States)

    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. Ethanol reassimilation and ethanol tolerance in Pitchia stipitis CBS 6054 as studied by [sup 13]C nuclear magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Skoog, K.; Hahn-Haegerdal, B. (Univ. of Lund (Sweden)); Degn, H.; Jacobsen, H.S.; Jacobsen, J.P. (Univ. of Odense (Denmark))

    1992-08-01

    Ethanol reassimilation in Pichia stipitis CBS 6054 was studied by using continuous cultures, and the oxidation of [1-[sup 13]C] ethanol was monitored by in vivo and in vitro [sup 13]C nuclear magnetic resonance spectroscopy. Acetate was formed when ethanol was reassimilated. The ATP/ADP ratio and the carbon dioxide production decreased, whereas the malate dehydrogenase activity increased, in ethanol-reassimilating cells. The results are discussed in terms of the low ethanol tolerance in P. stipitis compared with that in Saccharomyces cerevisiae.

  10. Measurement of soil carbon oxidation state and oxidative ratio by 13C nuclear magnetic resonance

    Science.gov (United States)

    Hockaday, W.C.; Masiello, C.A.; Randerson, J.T.; Smernik, R.J.; Baldock, J.A.; Chadwick, O.A.; Harden, J.W.

    2009-01-01

    The oxidative ratio (OR) of the net ecosystem carbon balance is the ratio of net O2 and CO2 fluxes resulting from photosynthesis, respiration, decomposition, and other lateral and vertical carbon flows. The OR of the terrestrial biosphere must be well characterized to accurately estimate the terrestrial CO2 sink using atmospheric measurements of changing O2 and CO2 levels. To estimate the OR of the terrestrial biosphere, measurements are needed of changes in the OR of aboveground and belowground carbon pools associated with decadal timescale disturbances (e.g., land use change and fire). The OR of aboveground pools can be measured using conventional approaches including elemental analysis. However, measuring the OR of soil carbon pools is technically challenging, and few soil OR data are available. In this paper we test three solid-state nuclear magnetic resonance (NMR) techniques for measuring soil OR, all based on measurements of the closely related parameter, organic carbon oxidation state (Cox). Two of the three techniques make use of a molecular mixing model which converts NMR spectra into concentrations of a standard suite of biological molecules of known C ox. The third technique assigns Cox values to each peak in the NMR spectrum. We assess error associated with each technique using pure chemical compounds and plant biomass standards whose Cox and OR values can be directly measured by elemental analyses. The most accurate technique, direct polarization solid-state 13C NMR with the molecular mixing model, agrees with elemental analyses to ??0.036 Cox units (??0.009 OR units). Using this technique, we show a large natural variability in soil Cox and OR values. Soil Cox values have a mean of -0.26 and a range from -0.45 to 0.30, corresponding to OR values of 1.08 ?? 0.06 and a range from 0.96 to 1.22. We also estimate the OR of the carbon flux from a boreal forest fire. Analysis of soils from nearby intact soil profiles imply that soil carbon losses associated

  11. 13C Nuclear Magnetic Resonance Study of Acetate Incorporation into Malate During Ca2+-Uptake by Isolated Leaf Tissues 1

    Science.gov (United States)

    Borchert, Rolf; Everett, Grover W.

    1987-01-01

    13C Nuclear magnetic resonance spectroscopy of leaflets of Gleditsia triacanthos and Albizia julibrisin was used to determine the fate of acetate taken up during the absorption of calcium from 13C-labeled Ca-acetate solution. Small amounts of acetate accumulated temporarily in the leaf tissues, but the bulk of acetate was incorporated into malate. The initial rate of malate synthesis was very low, but increased rapidly during acetate treatment and reached its maximum after 8 hours; the enzymes involved in malate synthesis thus appear to be substrate induced. Use of acetate-2-13C yielded malate labeled in C-3, indicating that vacuolar malate accumulating during Ca-uptake might be synthesized via malate synthase from acetate and glyoxalate. However, a source of glyoxalate condensing with acetate during malate synthesis could not be identified. Glycolate produced in photorespiration is an unlikely source, because glycolate-2-13C was absorbed and metabolized by the leaf tissues into products of the glycolate pathway, but was not a major precursor in malate synthesis. Malate synthesis via the glyoxalate cycle is also unlikely, because no evidence for the recycling of a 13C-labeled 4-carbon organic acid was found. Malate synthesis in the leaflets of Gleditsia and Albizia thus appears to involve the inducible condensation of acetate with a 2-carbon compound of unidentified nature and origin. PMID:16665548

  12. Cross polarization, magic-angle spinning /sup 13/C nuclear magnetic resonance spectroscopy of soil humic fractions

    Energy Technology Data Exchange (ETDEWEB)

    Saiz-Jimenez, C.; Hawkins, B.L.; Maciel, G.E.

    1986-01-01

    Cross polarization, magic-angle spinning /sup 13/C nuclear magnetic resonance spectroscopy was used to characterize humic fractions isolated from different soils. The humic acid fractions are more aromatic than the humin fractions, probably due to the higher polysaccharide content of humins. However, fulvic acid fractions are more aromatic than the corresponding humic acid and humin fractions. These results can be interpreted in terms of the isolation procedure, because the high affinity of Polyclar AT for phenols results in higher aromaticities as compared with other isolation methods (e.g. charcoal).

  13. Oil stability prediction by high-resolution (13)C nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Hidalgo, Francisco J; Gómez, Gemma; Navarro, José L; Zamora, Rosario

    2002-10-09

    (13)C NMR spectra of oil fractions obtained chromatographically from 66 vegetable oils were obtained and analyzed to evaluate the potential use of those fractions in predicting oil stabilities and to compare those results with oil stability prediction by using chemical determinations. The oils included the following: virgin olive oils from different cultivars and regions of Europe and north Africa; "lampante" olive, refined olive, refined olive pomace, low-erucic rapeseed, high-oleic sunflower, corn, grapeseed, soybean, and sunflower oils. Oils were analyzed for fatty acid and triacylglycerol composition, as well as for phenol and tocopherol contents. By using stepwise linear regression analysis (SLRA), the chemical determinations and the (13)C NMR data that better explained the oil stability determined by the Rancimat were selected. These selected variables were related to both the susceptibility of the oil to be oxidized and the content of minor components that most contributed to oil stability. Because (13)C NMR considered many more variables than those determined by chemical analysis, the predicted stabilities calculated by using NMR data were always better than those obtained by using chemical determinations. All these results suggest that (13)C NMR may be a powerful tool to predict oil stabilities when applied to chromatographically enriched oil fractions.

  14. Catabolism of glucose and lactose in Bifidobacterium animalis subsp. lactis, studied by 13C Nuclear Magnetic Resonance.

    Science.gov (United States)

    González-Rodríguez, Irene; Gaspar, Paula; Sánchez, Borja; Gueimonde, Miguel; Margolles, Abelardo; Neves, Ana Rute

    2013-12-01

    Bifidobacteria are widely used as probiotics in several commercial products; however, to date there is little knowledge about their carbohydrate metabolic pathways. In this work, we studied the metabolism of glucose and lactose in the widely used probiotic strain Bifidobacterium animalis subsp. lactis BB-12 by in vivo (13)C nuclear magnetic resonance (NMR) spectroscopy. The metabolism of [1-(13)C]glucose was characterized in cells grown in glucose as the sole carbon source. Moreover, the metabolism of lactose specifically labeled with (13)C on carbon 1 of the glucose or the galactose moiety was determined in suspensions of cells grown in lactose. These experiments allowed the quantification of some intermediate and end products of the metabolic pathways, as well as determination of the consumption rate of carbon sources. Additionally, the labeling patterns in metabolites derived from the metabolism of glucose specifically labeled with (13)C on carbon 1, 2, or 3 in cells grown in glucose or lactose specifically labeled in carbon 1 of the glucose moiety ([1-(13)Cglucose]lactose), lactose specifically labeled in carbon 1 of the galactose moiety ([1-(13)Cgalactose]lactose), and [1-(13)C]glucose in lactose-grown cells were determined in cell extracts by (13)C NMR. The NMR analysis showed that the recovery of carbon was fully compatible with the fructose 6-phosphate, or bifid, shunt. The activity of lactate dehydrogenase, acetate kinase, fructose 6-phosphate phosphoketolase, and pyruvate formate lyase differed significantly between glucose and lactose cultures. The transcriptional analysis of several putative glucose and lactose transporters showed a significant induction of Balat_0475 in the presence of lactose, suggesting a role for this protein as a lactose permease. This report provides the first in vivo experimental evidence of the metabolic flux distribution in the catabolic pathway of glucose and lactose in bifidobacteria and shows that the bifid shunt is the only

  15. Espectroscopia de Ressonância Magnética Nuclear de 13C no estudo de rotas biossintéticas de produtos naturais 13C Nuclear Magnetic Resonance spectroscopy in the studies of biosythetic routes of natural products

    Directory of Open Access Journals (Sweden)

    Fernando César de Macedo Júnior

    2007-02-01

    Full Text Available During the last five decades, as a result of an interaction between natural product chemistry, synthetic organic chemistry, molecular biology and spectroscopy, scientists reached an extraordinary level of comprehension about the natural processes by which living organisms build up complex molecules. In this context, 13C nuclear magnetic resonance spectroscopy, allied with isotopic labeling, played a determinant role. Nowadays, the widespread use of modern NMR techniques allows an even more detailed picture of the biochemical steps by accurate manipulation of the atomic nuclei. This article focuses on the development of such techniques and their impact on biosynthetic studies.

  16. Conditions to obtain precise and true measurements of the intramolecular {sup 13}C distribution in organic molecules by isotopic {sup 13}C nuclear magnetic resonance spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bayle, Kevin [EBSI Team, Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 Rue de la Houssinière, BP 92208, F-44322, Nantes Cedex 3 (France); Gilbert, Alexis [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Earth–Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan); Julien, Maxime [EBSI Team, Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 Rue de la Houssinière, BP 92208, F-44322, Nantes Cedex 3 (France); Yamada, Keita [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Silvestre, Virginie; Robins, Richard J.; Akoka, Serge [EBSI Team, Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 Rue de la Houssinière, BP 92208, F-44322, Nantes Cedex 3 (France); Yoshida, Naohiro [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Earth–Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan); Remaud, Gérald S., E-mail: gerald.remaud@univ-nantes.fr [EBSI Team, Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 Rue de la Houssinière, BP 92208, F-44322, Nantes Cedex 3 (France)

    2014-10-10

    Highlights: • Evaluation of the trueness and precision criteria of isotopic {sup 13}C NMR spectrometry. • Use of bi-labelled [1,2-{sup 13}C{sub 2}]acetic acid to determine the performance of the instrumental response. • Inter-calibration of the {sup 13}C intramolecular composition of acetic acid using the technique GC-Py–irm-MS. - Abstract: Intramolecular {sup 13}C composition gives access to new information on the (bio) synthetic history of a given molecule. Isotopic {sup 13}C NMR spectrometry provides a general tool for measuring the position-specific {sup 13}C content. As an emerging technique, some aspects of its performance are not yet fully delineated. This paper reports on (i) the conditions required to obtain satisfactory trueness and precision for the determination of the internal {sup 13}C distribution, and (ii) an approach to determining the “absolute” position-specific {sup 13}C content. In relation to (i), a precision of <1% can be obtained whatever the molecule on any spectrometer, once quantitative conditions are met, in particular appropriate proton decoupling efficiency. This performance is a prerequisite to the measurement of isotope fractionation either on the transformed or residual compound when a chemical reaction or process is being studied. The study of the trueness has revealed that the response of the spectrometer depends on the {sup 13}C frequency range of the studied molecule, i.e. the chemical shift range. The “absolute value” and, therefore, the trueness of the {sup 13}C NMR measurements has been assessed on acetic acid and by comparison to the results obtained on the fragments from COOH and CH{sub 3} by isotopic mass spectrometry coupled to a pyrolysis device (GC-Py–irm-MS), this technique being the reference method for acetic acid. Of the two NMR spectrometers used in this work, one gave values that corresponded to those obtained by GC-Py–irm-MS (thus, the “true” value) while the other showed a bias, which was

  17. Site-specific {sup 13}C content by quantitative isotopic {sup 13}C Nuclear Magnetic Resonance spectrometry: A pilot inter-laboratory study

    Energy Technology Data Exchange (ETDEWEB)

    Chaintreau, Alain; Fieber, Wolfgang; Sommer, Horst [Firmenich SA, Corporate R and D Division, P.O. Box 239, 1211 Geneva 8 (Switzerland); Gilbert, Alexis; Yamada, Keita [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Yoshida, Naohiro [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Earth-Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan); Pagelot, Alain [Bruker Biospin SAS, 34 rue de l‘Industrie, 67166 Wissembourg Cedex (France); Moskau, Detlef; Moreno, Aitor [Bruker Biospin AG, Industriestrasse 26, 8117 Fällanden (Switzerland); Schleucher, Jürgen [Department of Medical Biochemistry and Biophysics, Umeå University, S-90187 Umeå (Sweden); Reniero, Fabiano; Holland, Margaret; Guillou, Claude [European Commission, Joint Research Centre – Institute for Health and Consumer Protection, via E. Fermi 2749, I-21027 Ispra (Italy); Silvestre, Virginie; Akoka, Serge [EBSI team, Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes cedex 3 (France); Remaud, Gérald S., E-mail: gerald.remaud@univ-nantes.fr [EBSI team, Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes cedex 3 (France)

    2013-07-25

    Graphical abstract: -- Highlights: •First ring test on isotopic {sup 13}C NMR spectrometry. •Evaluation of the intra- and inter-variability of the NMR spectrometers used. •Definition of a protocol for qualification of the performance of the spectrometer. -- Abstract: Isotopic {sup 13}C NMR spectrometry, which is able to measure intra-molecular {sup 13}C composition, is of emerging demand because of the new information provided by the {sup 13}C site-specific content of a given molecule. A systematic evaluation of instrumental behaviour is of importance to envisage isotopic {sup 13}C NMR as a routine tool. This paper describes the first collaborative study of intra-molecular {sup 13}C composition by NMR. The main goals of the ring test were to establish intra- and inter-variability of the spectrometer response. Eight instruments with different configuration were retained for the exercise on the basis of a qualification test. Reproducibility at the natural abundance of isotopic {sup 13}C NMR was then assessed on vanillin from three different origins associated with specific δ{sup 13}C{sub i} profiles. The standard deviation was, on average, between 0.9 and 1.2‰ for intra-variability. The highest standard deviation for inter-variability was 2.1‰. This is significantly higher than the internal precision but could be considered good in respect of a first ring test on a new analytical method. The standard deviation of δ{sup 13}C{sub i} in vanillin was not homogeneous over the eight carbons, with no trend either for the carbon position or for the configuration of the spectrometer. However, since the repeatability for each instrument was satisfactory, correction factors for each carbon in vanillin could be calculated to harmonize the results.

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

    Science.gov (United States)

    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.

  19. Determination of refractory organic matter in marine sediments by chemical oxidation, analytical pyrolysis and solid-state 13C nuclear magnetic resonance spectroscopy

    OpenAIRE

    Rosa Arranz, José M. de la; González-Pérez, José Antonio; Hatcher, Patrick G.; Knicker, Heike; González-Vila, Francisco Javier

    2008-01-01

    Seeking to quantify the amount of refractory organic matter (ROM), which includes black carbon-like material (BC), in marine sediments, we have applied a two-step procedure that consists of a chemical oxidation with sodium chlorite of the demineralized sediments followed by integration of the aromatic C region in the remaining residues by solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. The efficacy for lignin removal was tested by analytical pyrolysis in the presence of tetrame...

  20. Optical hyperpolarization of 13C nuclear spins in nanodiamond ensembles

    Science.gov (United States)

    Chen, Q.; Schwarz, I.; Jelezko, F.; Retzker, A.; Plenio, M. B.

    2015-11-01

    Dynamical nuclear polarization holds the key for orders of magnitude enhancements of nuclear magnetic resonance signals which, in turn, would enable a wide range of novel applications in biomedical sciences. However, current implementations of DNP require cryogenic temperatures and long times for achieving high polarization. Here we propose and analyze in detail protocols that can achieve rapid hyperpolarization of 13C nuclear spins in randomly oriented ensembles of nanodiamonds at room temperature. Our protocols exploit a combination of optical polarization of electron spins in nitrogen-vacancy centers and the transfer of this polarization to 13C nuclei by means of microwave control to overcome the severe challenges that are posed by the random orientation of the nanodiamonds and their nitrogen-vacancy centers. Specifically, these random orientations result in exceedingly large energy variations of the electron spin levels that render the polarization and coherent control of the nitrogen-vacancy center electron spins as well as the control of their coherent interaction with the surrounding 13C nuclear spins highly inefficient. We address these challenges by a combination of an off-resonant microwave double resonance scheme in conjunction with a realization of the integrated solid effect which, together with adiabatic rotations of external magnetic fields or rotations of nanodiamonds, leads to a protocol that achieves high levels of hyperpolarization of the entire nuclear-spin bath in a randomly oriented ensemble of nanodiamonds even at room temperature. This hyperpolarization together with the long nuclear-spin polarization lifetimes in nanodiamonds and the relatively high density of 13C nuclei has the potential to result in a major signal enhancement in 13C nuclear magnetic resonance imaging and suggests functionalized and hyperpolarized nanodiamonds as a unique probe for molecular imaging both in vitro and in vivo.

  1. Dereplication of depsides from the lichen Pseudevernia furfuracea by centrifugal partition chromatography combined to {sup 13}C nuclear magnetic resonance pattern recognition

    Energy Technology Data Exchange (ETDEWEB)

    Oettl, Sarah K. [Institute of Pharmacy/Pharmacognosy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80–82, 6020 Innsbruck (Austria); Hubert, Jane, E-mail: jane.hubert@univ-reims.fr [Institut de Chimie Moléculaire de Reims (UMR CNRS 7312), SFR CAP' sANTE, UFR de Pharmacie, Université de Reims Champagne-Ardenne, BP 1039, 51687 Reims Cedex 2 (France); Nuzillard, Jean-Marc [Institut de Chimie Moléculaire de Reims (UMR CNRS 7312), SFR CAP' sANTE, UFR de Pharmacie, Université de Reims Champagne-Ardenne, BP 1039, 51687 Reims Cedex 2 (France); Stuppner, Hermann [Institute of Pharmacy/Pharmacognosy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80–82, 6020 Innsbruck (Austria); Renault, Jean-Hugues [Institut de Chimie Moléculaire de Reims (UMR CNRS 7312), SFR CAP' sANTE, UFR de Pharmacie, Université de Reims Champagne-Ardenne, BP 1039, 51687 Reims Cedex 2 (France); Rollinger, Judith M. [Institute of Pharmacy/Pharmacognosy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80–82, 6020 Innsbruck (Austria)

    2014-10-10

    Highlights: • The major depsides of a lichen extract were directly identified within mixtures. • The initial extract was rapidly fractionated by CPC in the pH-zone refining mode. • Hierarchical clustering of {sup 13}C NMR signals resulted in the identification of depside molecular skeletons. • {sup 13}C chemical shift clusters were assigned to structures using a {sup 13}C NMR database. • Six depsides were unambiguously identified by this approach. - Abstract: Lichens produce a diversity of secondary metabolites, among them depsides comprised of two or more hydroxybenzoic acid units linked by ester, ether, or C-C-bonds. During classic solid support-based purification processes, depsides are often hydrolyzed and in many cases time, consuming procedures result only in the isolation of decomposition products. In an attempt to avoid extensive purification steps while maintaining metabolite structure integrity, we propose an alternative method to identify the major depsides of a lichen crude extract (Pseudevernia furfuracea var. ceratea (Ach.) D. Hawksw., Parmeliaceae) directly within mixtures. Exploiting the acidic character of depsides and differences in polarity, the extract was fractionated by centrifugal partition chromatography in the pH-zone refining mode resulting in twelve simplified mixtures of depsides. After {sup 13}C nuclear magnetic resonance analysis of the produced fractions, the major molecular structures were directly identified within the fraction series by using a recently developed pattern recognition method, which combines spectral data alignment and hierarchical clustering analysis. The obtained clusters of {sup 13}C chemical shifts were assigned to their corresponding molecular structures with the help of an in-house {sup 13}C NMR chemical shift database, resulting in six unambiguously identified compounds, namely methyl β-orcinolcarboxylate (1), atranorin (2), 5-chloroatranorin (3), olivetol carboxylic acid (4), olivetoric acid (5

  2. Enhanced forensic discrimination of pollutants by position-specific isotope analysis using isotope ratio monitoring by (13)C nuclear magnetic resonance spectrometry.

    Science.gov (United States)

    Julien, Maxime; Nun, Pierrick; Höhener, Patrick; Parinet, Julien; Robins, Richard J; Remaud, Gérald S

    2016-01-15

    In forensic environmental investigations the main issue concerns the inference of the original source of the pollutant for determining the liable party. Isotope measurements in geochemistry, combined with complimentary techniques for contaminant identification, have contributed significantly to source determination at polluted sites. In this work we have determined the intramolecular (13)C profiles of several molecules well-known as pollutants. By giving additional analytical parameters, position-specific isotope analysis performed by isotope ratio monitoring by (13)C nuclear magnetic resonance (irm-(13)C NMR) spectrometry gives new information to help in answering the major question: what is the origin of the detected contaminant? We have shown that isotope profiling of the core of a molecule reveals both the raw materials and the process used in its manufacture. It also can reveal processes occurring between the contamination site 'source' and the sampling site. Thus, irm-(13)C NMR is shown to be a very good complement to compound-specific isotope analysis currently performed by mass spectrometry for assessing polluted sites involving substantial spills of pollutant.

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

    KAUST Repository

    Bouhrara, M.

    2011-09-06

    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.

  4. Comparison of /sup 13/C nuclear magnetic resonance and /sup 14/C tracer studies of hepatic metabolism. [Rats and mice

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, S.M. (Merck Inst. for Therapeutic Research, Rathway, NJ); Rognstad, R.; Shulman, R.G.; Katz, J.

    1981-04-10

    The gluconeogenic pathway from /sup 13/C-labeled substrates, each of which contained the /sup 14/C-labeled counterpart at a tracer level, has been followed in isolated rat liver cells and in isolated perfused mouse liver. The gluconeogenic flux from glycerol, the synthesis of glycogen, the synthesis of glycogen, the stimulation of glycogenolysis by glucagon, the recycling of triacylglycerol, and an increase in pentose cycle activity under the influence of phenazine methosulfate were all observed directly in the /sup 13/C NMR spectra of perfused liver or isolated hepatocytes. The relative concentrations of /sup 13/C label at specific carbons measured by the NMR spectra under these conditions agreed closely with /sup 14/C isotopic distributions measured in extracts of the same doubly labeled samples for specific activities of greater than or equal to 3%. The label distributions measured by both methods were the same to within the experimental errors, which ranged from +-2% to +-7% in these experiments.

  5. Two-dimensional 1H-13C nuclear magnetic resonance (NMR)-based comprehensive analysis of roasted coffee bean extract.

    Science.gov (United States)

    Wei, Feifei; Furihata, Kazuo; Hu, Fangyu; Miyakawa, Takuya; Tanokura, Masaru

    2011-09-14

    Coffee was characterized by proton and carbon nuclear magnetic resonance (NMR) spectroscopy. To identify the coffee components, a detailed and approximately 90% signal assignment was carried out using various two-dimensional NMR spectra and a spiking method, in which authentic compounds were added to the roasted coffee bean extract (RCBE) sample. A total of 24 coffee components, including 5 polysaccharide units, 3 stereoisomers of chlorogenic acids, and 2 stereoisomers of quinic acids, were identified with the NMR spectra of RCBE. On the basis of the signal assignment, state analyses were further launched for the metal ion-citrate complexes and caffeine-chlorogenate complexes. On the basis of the signal integration, the coffee components were successfully quantified. This NMR methodology yielded detailed information on RCBE using only a single observation and provides a systemic approach for the analysis of other complex mixtures.

  6. Direct proof by 13C-nuclear magnetic resonance of semi-purified extract and isolation of ent-Catechin from leaves of Eucalyptus cinerea

    Science.gov (United States)

    Silva, Sayonara Mendes; Abe, Simone Yae; Bueno, Fernanda Giacomini; Lopes, Norberto Peporine; de Mello, João Carlos Palazzo; Nakashima, Tomoe

    2014-01-01

    Background: Eucalyptus cinerea F. Muell. ex Benth. is native to Australia and acclimatized to Southern Brazil. Its aromatic leaves are used for ornamental purposes and have great potential for essential oil production, although reports of its use in folk medicine are few. Objective: This study evaluated the composition of E. cinerea leaves using the solid state 13C-nuclear magnetic resonance (NMR) and isolation of the compound from the semipurified extract (SE). Materials and Methods: The SE of E. cinerea leaves was evaluated in the solid state by 13C-NMR spectrum, and the SE was chromatographed on a Sephadex LH-20 column, followed by high-speed counter-current chromatography to isolate the compound. The SE was analyzed by 13C-NMR and matrix-assisted laser desorption/ionization-time-of-flight spectra. Results: Flavan-3-ol units were present, suggesting the presence of proanthocyanidins as well as a gallic acid unit. The uncommon ent-catechin was isolated. Conclusion: The presence of ent-catechin is reported for the first time in this genus and species. PMID:25210302

  7. Direct Characterization of Kerogen by X-ray and Solid-State [superscript 13]C Nuclear Magnetic Resonance Methods

    Energy Technology Data Exchange (ETDEWEB)

    Kelemen, S. R.; Afeworki, M.; Gorbaty, M.L.; Sansone, M.; Kwiatek, P.J.; Walters, C.C.; Freund, H.; Siskin, M.; Bence, A.E.; Curry, D.J.; Solum, M.; Pugmire, R.J.; Vandenbroucke, M.; Leblond, M.; Behar, F. (ExxonMobil); (ExxonMobil); (IFP); (Utah)

    2008-06-12

    A combination of solid-state {sup 13}C NMR, X-ray photoelectron spectroscopy (XPS) and sulfur X-ray absorption near edge structure (S-XANES) techniques are used to characterize organic oxygen, nitrogen, and sulfur species and carbon chemical/structural features in kerogens. The kerogens studied represent a wide range of organic matter types and maturities. A van Krevelen plot based on elemental H/C data and XPS derived O/C data shows the well established pattern for type I, type II, and type III kerogens. The anticipated relationship between the Rock-Eval hydrogen index and H/C is independent of organic matter type. Carbon structural and lattice parameters are derived from solid-state {sup 13}C NMR analysis. As expected, the amount of aromatic carbon, measured by both {sup 13}C NMR and XPS, increases with decreasing H/C. The correlation between aromatic carbon and Rock-Eval T{sub max}, an indicator of maturity, is linear for types II and IIIC kerogens, but each organic matter type follows a different relationship. The average aliphatic carbon chain length (Cn) decreases with an increasing amount of aromatic carbon in a similar manner across all organic matter types. The fraction of aromatic carbons with attachments (FAA) decreases, while the average number of aromatic carbons per cluster (C) increases with an increasing amount of aromatic carbon. FAA values range from 0.2 to 0.4, and C values range from 12 to 20 indicating that kerogens possess on average 2- to 5-ring aromatic carbon units that are highly substituted. There is basic agreement between XPS and {sup 13}C NMR results for the amount and speciation of organic oxygen. XPS results show that the amount of carbon oxygen single bonded species increases and carbonyl-carboxyl species decrease with an increasing amount of aromatic carbon. Patterns for the relative abundances of nitrogen and sulfur species exist regardless of the large differences in the total amount of organic nitrogen and sulfur seen in the

  8. Detection of poly(ethylene glycol) residues from nonionic surfactants in surface water by1h and13c nuclear magnetic resonance spectrometry

    Science.gov (United States)

    Leenheer, J.A.; Wershaw, R. L.; Brown, P.A.; Noyes, T.I.

    1991-01-01

    ??? Poly(ethylene glycol) (PEG) residues were detected in organic solute isolates from surface water by 1H nuclear magnetic resonance spectrometry (NMR), 13C NMR spectrometry, and colorimetric assay. PEG residues were separated from natural organic solutes in Clear Creek, CO, by a combination of methylation and chromatographic procedures. The isolated PEG residues, characterized by NMR spectrometry, were found to consist of neutral and acidic residues that also contained poly(propylene glycol) moieties. The 1H NMR and the colorimetric assays for poly(ethylene glycol) residues were done on samples collected in the lower Mississippi River and tributaries between St. Louis, MO, and New Orleans, LA, in July-August and November-December 1987. Aqueous concentrations for poly(ethylene glycol) residues based on colorimetric assay ranged from undetectable to ???28 ??g/L. Concentrations based on 1H NMR spectrometry ranged from undetectable to 145 ??g/L.

  9. Detection of a covalent intermediate in the mechanism of action of porcine pancreatic alpha-amylase by using 13C nuclear magnetic resonance.

    Science.gov (United States)

    Tao, B Y; Reilly, P J; Robyt, J F

    1989-05-01

    The catalytic mechanism of porcine pancreatic alpha-amylase (1,4-alpha-D-glucan glucanohydrolase, EC 3.2.1.1) has been examined by nuclear magnetic resonance (NMR) at subzero temperatures by using [1-13C]maltotetraose as substrate. Spectral summation and difference techniques revealed a broad resonance peak, whose chemical shift, relative signal intensity and time-course appearance corresponded to a beta-carboxyl-acetal ester covalent enzyme-glycosyl intermediate. This evidence supports a double-displacement covalent mechanism for porcine pancreatic alpha-amylase-catalyzed hydrolysis of glycosidic linkages, based on the presence of catalytic aspartic acid residues within the active site of this enzyme.

  10. Titanium carbide, nitride and carbonitrides: a 13C, 14N, 15N and 47,49Ti solid-state nuclear magnetic resonance study.

    Science.gov (United States)

    MacKenzie, K J; Meinhold, R H; McGavin, D G; Ripmeester, J A; Moudrakovski, I

    1995-05-01

    The first 47,49Ti, 13C, 14N and 15N solid-state nuclear magnetic resonance (NMR) spectra of titanium carbide, nitride and a series of cubic carbonitrides have been obtained under both static and magic-angle spinning (MAS) conditions. The 15N samples were isotopically enriched by gas-solid exchange at 1000 degrees C in a closed system. The Ti spectra of the carbide and nitride are sharp, reflecting the well defined cubic symmetry of these compounds, but become considerably broadened in the carbonitride series, with the spectra being approximately the sum of TiC and TiN together with some small electric field gradient (EFG) effects. The resonance positions and widths of all the NMR spectra change as carbon is progressively replaced by nitrogen. A relationship is observed between the 13C chemical shift and the nitrogen content of the carbonitrides, suggesting a possible NMR method for estimating the composition of these compounds. Although electron paramagnetic resonance (EPR) spectra of all these compounds show typically metallic behaviour, the NMR spectra show few effects attributable to conduction electrons, probably due to the lack of s-orbital contributions to the conduction band.

  11. Investigation of gamma radiation effect on the anion exchange resin Amberlite IRA-400 in hydroxide form by Fourier transformed infrared and 13C nuclear magnetic resonance spectroscopies.

    Science.gov (United States)

    Traboulsi, A; Dupuy, N; Rebufa, C; Sergent, M; Labed, V

    2012-03-02

    Radiation-induced decomposition of the anion exchange resin Amberlite IRA-400 in hydroxide form by gamma radiolysis has been studied under different irradiation doses and irradiation atmospheres. In this work, we focused on the degradation of the solid part of the resin by Fourier transformed infrared (FTIR) and (13)C nuclear magnetic resonance (NMR) spectroscopies associated with chemometric treatments. FTIR and (13)C NMR techniques showed that only -CH(2)N(+)(CH(3))(3) groups were detached from the resin whereas the polystyrene divinylbenzene backbone remains intact. The quaternary ammonium groups were replaced by amine or carbonyl groups according to the irradiation atmosphere (with or without water or oxygen). Principal components analysis (PCA) was used to classify the degraded resins according to their irradiation conditions by separating the effect of the dose or the environment. The PCA loadings have shown spectral regions which discriminate the irradiated resins whereas SIMPLe-to-use Interactive Self-modeling Mixture Analysis (SIMPLISMA) allows to identify families of component characterizing the chemical structure of resins and estimate their relative contributions according to the irradiation atmospheres.

  12. Ascorbic acid prolongs the viability and stability of isolated perfused lungs: A mechanistic study using 31P and hyperpolarized 13C nuclear magnetic resonance.

    Science.gov (United States)

    Shaghaghi, Hoora; Kadlecek, Stephen; Siddiqui, Sarmad; Pourfathi, Mehrdad; Hamedani, Hooman; Clapp, Justin; Profka, Harrilla; Rizi, Rahim

    2015-12-01

    Ex vivo lung perfusion (EVLP) has recently shown promise as a means of more accurately gauging the health of lung grafts and improving graft performance post-transplant. However, reperfusion of ischemic lung promotes the depletion of high-energy compounds and a progressive loss of normal mitochondrial function, and it remains unclear how and to what extent the EVLP approach contributes to this metabolic decline. Although ascorbate has been used to mitigate the effects of ischemia-reperfusion injury, the nature of its effects during EVLP are also not clear. To address these uncertainties, this study monitored the energy status of lungs during EVLP and after the administration of ascorbate using (31)P and hyperpolarized (13)C NMR (nuclear magnetic resonance). Our experiments demonstrated that the oxidative phosphorylation capacity and pyruvate dehydrogenase flux of lungs decline during ex vivo perfusion. The addition of ascorbate to the perfusate prolonged lung viability by 80% and increased the hyperpolarized (13)C bicarbonate signal by a factor of 2.7. The effect of ascorbate is apparently due not to its antioxidant quality but rather to its ability to energize cellular respiration given that it increased the lung's energy charge significantly, whereas other antioxidants (glutathione and α-lipoic acid) did not alter energy metabolism. During ascorbate administration, inhibition of mitochondrial complex I with rotenone depressed energy charge and shifted the metabolic state of the lung toward glycolysis; reenergizing the electron transport chain with TMPD (N,N,N',N'-tetramethyl-p-phenylenediamine) recovered metabolic activity. This indicates that ascorbate slows the decline of the ex vivo perfused lung's mitochondrial activity through an independent interaction with the electron transport chain complexes.

  13. Metabolic Pathway for Propionate Utilization by Phosphorus-Accumulating Organisms in Activated Sludge: 13C Labeling and In Vivo Nuclear Magnetic Resonance

    Science.gov (United States)

    Lemos, Paulo C.; Serafim, Luísa S.; Santos, Margarida M.; Reis, Maria A. M.; Santos, Helena

    2003-01-01

    In vivo 13C and 31P nuclear magnetic resonance techniques were used to study propionate metabolism by activated sludge in enhanced biological phosphorus removal systems. The fate of label supplied in [3-13C]propionate was monitored in living cells subjected to anaerobic/aerobic cycles. During the anaerobic phase, propionate was converted to polyhydroxyalkanoates (PHA) with the following monomer composition: hydroxyvalerate, 74.2%; hydroxymethylvalerate, 16.9%; hydroxymethylbutyrate, 8.6%; and hydroxybutyrate, 0.3%. The isotopic enrichment in the different carbon atoms of hydroxyvalerate (HV) produced during the first anaerobic stage was determined: HV5, 59%; HV4, 5.0%; HV3, 1.1%; HV2, 3.5%; and HV1, 2.8%. A large proportion of the supplied label ended up on carbon C-5 of HV, directly derived from the pool of propionyl-coenzyme A (CoA), which is primarily labeled on C-3; useful information on the nature of operating metabolic pathways was provided by the extent of labeling on C-1, C-2, and C-4. The labeling pattern on C-1 and C-2 was explained by the conversion of propionyl-CoA to acetyl-CoA via succinyl-CoA and the left branch of the tricarboxylic acid cycle, which involves scrambling of label between the inner carbons of succinate. This constitutes solid evidence for the operation of succinate dehydrogenase under anaerobic conditions. The labeling in HV4 is explained by backflux from succinate to propionyl-CoA. The involvement of glycogen in the metabolism of propionate was also demonstrated; moreover, it was shown that the acetyl moiety to the synthesis of PHA was derived preferentially from glycogen. According to the proposed metabolic scheme, the decarboxylation of pyruvate is coupled to the production of hydrogen, and the missing reducing equivalents should be derived from a source other than glycogen metabolism. PMID:12514001

  14. Investigating the lignocellulosic composition during delignification using confocal raman spectroscopy, cross-polarization magic angle spinning carbon 13 - nuclear magnetic resonance (CP/MAS 13C- NMR) spectroscopy and atomic force microscopy

    CSIR Research Space (South Africa)

    Chunilall, Viren

    2012-03-01

    Full Text Available spectroscopy, Cross-Polarization Magic Angle Spinning Carbon 13 - Nuclear Magnetic Resonance (CP/MAS 13C-NMR) spectroscopy and Atomic Force Microscopy (AFM) in conjunction with image analysis. The confocal Raman results showed that there were differences...

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

    Science.gov (United States)

    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.

  16. Dynamic nuclear polarization and optimal control spatial-selective 13C MRI and MRS

    DEFF Research Database (Denmark)

    Vinding, Mads Sloth; Laustsen, Christoffer; Maximov, Ivan I.

    2013-01-01

    Aimed at 13C metabolic magnetic resonance imaging (MRI) and spectroscopy (MRS) applications, we demonstrate that dynamic nuclear polarization (DNP) may be combined with optimal control 2D spatial selection to simultaneously obtain high sensitivity and well-defined spatial restriction. This is ach......Aimed at 13C metabolic magnetic resonance imaging (MRI) and spectroscopy (MRS) applications, we demonstrate that dynamic nuclear polarization (DNP) may be combined with optimal control 2D spatial selection to simultaneously obtain high sensitivity and well-defined spatial restriction....... This is achieved through the development of spatial-selective single-shot spiral-readout MRI and MRS experiments combined with dynamic nuclear polarization hyperpolarized [1-13C]pyruvate on a 4.7T pre-clinical MR scanner. The method stands out from related techniques by facilitating anatomic shaped region...

  17. Possibilities and limitations of sup 1 H and sup 13 C nuclear magnetic resonance spectroscopy for the identification and the quantitative determination of some naturally occurring carcinogenic risk factors. [Senecio vulgaris; Senecio vernalis; Senecio jacobaea; Euphorbia ingens

    Energy Technology Data Exchange (ETDEWEB)

    Pieters, L.

    1988-01-01

    The aim of this work was to develop a phytochemical screening method for some selected carcinogenic or tumor-promoting principles in higher plants. The pyrrolizidine alkaloids from some Senecio species (Compositae or Asteraceae), and the diterpene ester from Croton tiglium L. and Euphorbia ingens E. Mey (Euphorbiaceae) were chosen as representatives of both groups. The possibilities and limitations of {sup 1}H and {sup 13}C nuclear magnetic resonance spectroscopy ({sup 1}H and {sup 13}C NMR) for the analysis of mixtures of carcinogenic pyrrolizidine alkaloids were compared with high performance liquid chromatography, and gas chromatography with high performance liquid chromatography, and gas chromatography was well as gas chromatography - mass spectrometry. Senecio vulgaris L., Senecio vernalis Waldst. and Kit. and Senecio jacobaea L. were investigated.

  18. Methyl-²-D-glucopyranoside in higher plants: accumulation and intracellular localization in Geum montanum L. leaves and in model systems studied by 13C nuclear magnetic resonance

    National Research Council Canada - National Science Library

    S. Aubert; P. Choler; J. Pratt; R. Douzet; E. Gout; R. Bligny

    2004-01-01

    .... Incubating intact plant tissues, culture cells, and purified organelles with 13C-labelled substrates showed that MeG was synthesized in the cytosol of cells, directly from glucose and methanol molecules...

  19. 13C High-Resolution Nuclear Magnetic Resonance Studies of Enzyme-Substrate Reactions at Equilibrium. Substrate Strain Studies of Chymotrypsin-N-Acetyltyrosine Semicarbazide Complexes

    NARCIS (Netherlands)

    Robillard, George; Shaw, Elliott; Shulman, R.G.

    1974-01-01

    N-Acetyl-L-tyrosine semicarbazide is hydrolyzed by chymotrypsin (EC 3.4.21.1) to N-acetyl-L-tyrosine and semicarbazide. If a high concentration of semicarbazide is present, the equilibrium for the reaction can be shifted from hydrolysis to synthesis. Using N-acetyl-L-[13C]tyrosine enriched at the

  20. The effect of oxygen on methanol oxidation by an obligate metahnotrophic bacterium studied by in vivo 13C nuclear magnetic resonance spectroscopy

    NARCIS (Netherlands)

    Costa, C.; Vecherskaya, M.; Dijkema, C.; Stams, A.J.M.

    2001-01-01

    13C NMR was used to study the effect of oxygen on methanol oxidation by a type II methanotrophic bacterium isolated from a bioreactor in which methane was used as electron donor for denitrification. Under high (35-25€oxygen conditions the first step of methanol oxidation to formaldehyde was much

  1. Theoretical and experimental studies of chemically induced dynamic nuclear polarization kinetics in recombination of radical pairs by the method of switched external magnetic field. II. 13C CIDNP of micellized radical pairs

    Science.gov (United States)

    Fedin, M. V.; Bagryanskaya, E. G.; Purtov, P. A.

    1999-09-01

    The method of 13C chemically induced dynamic nuclear polarization in a switched external magnetic field (SEMF CIDNP) has been applied for the first time in an experimental investigation of micellized radical pairs (RP). Using the examples of three photochemical reactions it has been shown, that SEMF CIDNP allows the investigation of the kinetics of short-lived micellized RPs with high time-resolution in low and intermediate magnetic fields. The experimental kinetics have been analyzed and simulated on the basis of a previously developed theory [Parnachev et al., J. Chem. Phys. 107, 9942 (1997)]. It has been demonstrated that such an analysis provides information on the rates of radical escape from the micelle, on electron relaxation and on the rate of S-T- transitions. The analysis of the estimated rates of S-T- transitions showed that the exchange interaction is essentially anisotropic in the RPs studied.

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

    Science.gov (United States)

    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.

  3. Monolayer to interdigitated partial bilayer smectic C transition in thiophene-based spacer mesogens: X-ray diffraction and (13)C nuclear magnetic resonance studies.

    Science.gov (United States)

    Kesava Reddy, M; Varathan, E; Lobo, Nitin P; Roy, Arun; Narasimhaswamy, T; Ramanathan, K V

    2015-10-06

    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.

  4. Biological degradation of tannins in sericea lespedeza (Lespedeza cuneata) by the white rot fungi Ceriporiopsis subvermispora and Cyathus stercoreus analyzed by solid-state 13C nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Gamble, G R; Akin, D E; Makkar, H P; Becker, K

    1996-10-01

    Leaves of sericea lespedeza exhibit a high proportion of condensed tannin, resulting in poor forage quality. The white rot fungi Ceriporiopsis subvermispora and Cyathus sterocoreus are known to preferentially degrade lignin in a variety of plants and were evaluated for their ability to degrade condensed tannin from sericea leaves with the aim of improving digestibility. Relative levels of condensed tannin, cutin, pectin, and cellulose were monitored as a function of fungal treatment by solid-state cross-polarization and magic angle spinning 13C nuclear magnetic resonance spectroscopy. Total soluble phenolics, soluble tannins, and soluble and insoluble proanthocyanidin levels in fungus-treated and control samples were measured by established chemical techniques. Results indicate that both species of fungus preferentially degrade condensed tannin and that C. subvermispora is markedly superior to C. stercoreus in this capacity.

  5. Hyperpolarized 13C metabolic imaging using dissolution dynamic nuclear polarization

    DEFF Research Database (Denmark)

    Hurd, Ralph E.; Yen, Yi‐Fen; Chen, Albert

    2012-01-01

    This article describes the basic physics of dissolution dynamic nuclear polarization (dissolution‐DNP), and the impact of the resulting highly nonequilibrium spin states, on the physics of magnetic resonance imaging (MRI) detection. The hardware requirements for clinical translation...... of this technology are also presented. For studies that allow the use of externally administered agents, hyperpolarization offers a way to overcome normal magnetic resonance sensitivity limitations, at least for a brief T1‐dependent observation window. A 10,000–100,000‐fold signal‐to‐noise advantage provides...

  6. Electron-nuclear interaction in 13C nanotube double quantum dots

    Science.gov (United States)

    Churchill, H. O. H.; Bestwick, A. J.; Harlow, J. W.; Kuemmeth, F.; Marcos, D.; Stwertka, C. H.; Watson, S. K.; Marcus, C. M.

    2009-05-01

    For coherent electron spins, hyperfine coupling to nuclei in the host material can either be a dominant source of unwanted spin decoherence or, if controlled effectively, a resource enabling storage and retrieval of quantum information. To investigate the effect of a controllable nuclear environment on the evolution of confined electron spins, we have fabricated and measured gate-defined double quantum dots with integrated charge sensors made from single-walled carbon nanotubes with a variable concentration of 13C (nuclear spin I=1/2) among the majority zero-nuclear-spin 12C atoms. We observe strong isotope effects in spin-blockaded transport, and from the magnetic field dependence estimate the hyperfine coupling in 13C nanotubes to be of the order of 100μeV, two orders of magnitude larger than anticipated. 13C-enhanced nanotubes are an interesting system for spin-based quantum information processing and memory: the 13C nuclei differ from those in the substrate, are naturally confined to one dimension, lack quadrupolar coupling and have a readily controllable concentration from less than one to 105 per electron.

  7. High-field dissolution dynamic nuclear polarization of [1-13C]pyruvic acid

    DEFF Research Database (Denmark)

    Yoshihara, Hikari A. I.; Can, Emine; Karlsson, Magnus

    2016-01-01

    [1-13C]pyruvate is the most widely used hyperpolarized metabolic magnetic resonance imaging agent. Using a custom-built 7.0 T polarizer operating at 1.0 K and trityl radical-doped [1-13C]pyruvic acid, unextrapolated solution-state 13C polarization greater than 60% was measured after dissolution a...

  8. Size dependence of 13C nuclear spin-lattice relaxation in micro- and nanodiamonds

    Science.gov (United States)

    Panich, A. M.; Sergeev, N. A.; Shames, A. I.; Osipov, V. Yu; Boudou, J.-P.; Goren, S. D.

    2015-02-01

    Size dependence of physical properties of nanodiamond particles is of crucial importance for various applications in which defect density and location as well as relaxation processes play a significant role. In this work, the impact of defects induced by milling of micron-sized synthetic diamonds was studied by magnetic resonance techniques as a function of the particle size. EPR and 13C NMR studies of highly purified commercial synthetic micro- and nanodiamonds were done for various fractions separated by sizes. Noticeable acceleration of 13C nuclear spin-lattice relaxation with decreasing particle size was found. We showed that this effect is caused by the contribution to relaxation coming from the surface paramagnetic centers induced by sample milling. The developed theory of the spin-lattice relaxation for such a case shows good compliance with the experiment.

  9. Size dependence of 13C nuclear spin-lattice relaxation in micro- and nanodiamonds.

    Science.gov (United States)

    Panich, A M; Sergeev, N A; Shames, A I; Osipov, V Yu; Boudou, J-P; Goren, S D

    2015-02-25

    Size dependence of physical properties of nanodiamond particles is of crucial importance for various applications in which defect density and location as well as relaxation processes play a significant role. In this work, the impact of defects induced by milling of micron-sized synthetic diamonds was studied by magnetic resonance techniques as a function of the particle size. EPR and (13)C NMR studies of highly purified commercial synthetic micro- and nanodiamonds were done for various fractions separated by sizes. Noticeable acceleration of (13)C nuclear spin-lattice relaxation with decreasing particle size was found. We showed that this effect is caused by the contribution to relaxation coming from the surface paramagnetic centers induced by sample milling. The developed theory of the spin-lattice relaxation for such a case shows good compliance with the experiment.

  10. 13C magnetic resonance spectroscopy measurements with hyperpolarized [1‐13C] pyruvate can be used to detect the expression of transgenic pyruvate decarboxylase activity in vivo

    Science.gov (United States)

    Dzien, Piotr; Tee, Sui‐Seng; Kettunen, Mikko I.; Lyons, Scott K.; Larkin, Timothy J.; Timm, Kerstin N.; Hu, De‐En; Wright, Alan; Rodrigues, Tiago B.; Serrao, Eva M.; Marco‐Rius, Irene; Mannion, Elizabeth; D'Santos, Paula; Kennedy, Brett W. C.

    2015-01-01

    Purpose Dissolution dynamic nuclear polarization can increase the sensitivity of the 13C magnetic resonance spectroscopy experiment by at least four orders of magnitude and offers a novel approach to the development of MRI gene reporters based on enzymes that metabolize 13C‐labeled tracers. We describe here a gene reporter based on the enzyme pyruvate decarboxylase (EC 4.1.1.1), which catalyzes the decarboxylation of pyruvate to produce acetaldehyde and carbon dioxide. Methods Pyruvate decarboxylase from Zymomonas mobilis (zmPDC) and a mutant that lacked enzyme activity were expressed using an inducible promoter in human embryonic kidney (HEK293T) cells. Enzyme activity was measured in the cells and in xenografts derived from the cells using 13C MRS measurements of the conversion of hyperpolarized [1‐13C] pyruvate to H13 CO3–. Results Induction of zmPDC expression in the cells and in the xenografts derived from them resulted in an approximately two‐fold increase in the H13 CO3–/[1‐13C] pyruvate signal ratio following intravenous injection of hyperpolarized [1‐13C] pyruvate. Conclusion We have demonstrated the feasibility of using zmPDC as an in vivo reporter gene for use with hyperpolarized 13C MRS. Magn Reson Med 76:391–401, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. PMID:26388418

  11. Study and validity of {sup 13}C stable carbon isotopic ratio analysis by mass spectrometry and {sup 2}H site-specific natural isotopic fractionation by nuclear magnetic resonance isotopic measurements to characterize and control the authenticity of honey

    Energy Technology Data Exchange (ETDEWEB)

    Cotte, J.F. [Cooperative France Miel, BP 5, 330 Mouchard (France); Casabianca, H. [Service Central d' Analyse, USR 059-CNRS, BP 22, 69390 Vernaison (France); Lheritier, J. [Cooperative France Miel, BP 5, 330 Mouchard (France); Perrucchietti, C. [Service Central d' Analyse, USR 059-CNRS, BP 22, 69390 Vernaison (France); Sanglar, C. [Service Central d' Analyse, USR 059-CNRS, BP 22, 69390 Vernaison (France); Waton, H. [Service Central d' Analyse, USR 059-CNRS, BP 22, 69390 Vernaison (France); Grenier-Loustalot, M.F. [Service Central d' Analyse, USR 059-CNRS, BP 22, 69390 Vernaison (France)]. E-mail: mf.grenier-loustalot@sca.cnrs.fr

    2007-01-16

    Honey samples were analyzed by stable carbon isotopic ratio analysis by mass spectrometry (SCIRA-MS) and site-specific natural isotopic fractionation measured by nuclear magnetic resonance (SNIF-NMR) to first determine their potentials for characterizing the substance and then to combat adulteration. Honey samples from several geographic and botanical origins were analyzed. The {delta} {sup 13}C parameter was not significant for characterizing an origin, while the (D/H){sub I} ratio could be used to differentiate certain single-flower varieties. Application of the official control method of adding a C{sub 4} syrup (AOAC official method 998.12) to our authentic samples revealed anomalies resulting from SCIRA indices that were more negative than -1 per mille (permil). A filtration step was added to the experimental procedure and provided results that were compliant with Natural origin of our honey samples. In addition, spiking with a C{sub 4} syrup could be detected starting at 9-10%. The use of SNIF-NMR is limited by the detection of a syrup spike starting only at 20%, which is far from satisfying.

  12. The use of dynamic nuclear polarization 13C-pyruvate MRS in cancer

    DEFF Research Database (Denmark)

    Borgwardt, Henrik Gutte; Espe Hansen, Adam; Hjort Johannesen, Helle

    2015-01-01

    -pyruvate due to favoring technicalities. Intravenous injection of the hyperpolarized 13C-pyruvate results in appearance of 13C-lactate, 13C-alanine and 13C-bicarbonate resonance peaks depending on the tissue, disease and the metabolic state probed. In cancer, the lactate level is increased due to increased...... of hyperpolarized 13C-pyruvate in healthy subjects and prostate cancer patients. The study showed an elevated 13C-lactate/13C-pyruvate ratio in regions of biopsy-proven prostate cancer compared to noncancerous tissue. However, more studies are needed in order to establish use of hyperpolarized 13C MRS imaging......In recent years there has been an immense development of new targeted anti-cancer drugs. For practicing precision medicine, a sensitive method imaging for non-invasive, assessment of early treatment response and for assisting in developing new drugs is warranted. Magnetic Resonance Spectroscopy...

  13. Electron-nuclear interaction in 13C nanotube double quantum dots

    DEFF Research Database (Denmark)

    Churchill, H O H; Bestwick, A J; Harlow, J W

    2009-01-01

    environment on the evolution of confined electron spins, we have fabricated and measured gate-defined double quantum dots with integrated charge sensors made from single-walled carbon nanotubes with a variable concentration of 13C (nuclear spin I=1/2) among the majority zero-nuclear-spin 12C atoms. We observe...... strong isotope effects in spin-blockaded transport, and from the magnetic field dependence estimate the hyperfine coupling in 13C nanotubes to be of the order of 100 ¿µeV, two orders of magnitude larger than anticipated. 13C-enhanced nanotubes are an interesting system for spin-based quantum information...

  14. The use of dynamic nuclear polarization (13)C-pyruvate MRS in cancer

    DEFF Research Database (Denmark)

    Gutte Borgwardt, Henrik; Hansen, Adam Espe; Johannesen, Helle Hjorth

    2015-01-01

    -pyruvate due to favoring technicalities. Intravenous injection of the hyperpolarized (13)C-pyruvate results in appearance of (13)C-lactate, (13)C-alanine and (13)C-bicarbonate resonance peaks depending on the tissue, disease and the metabolic state probed. In cancer, the lactate level is increased due...... the safety of hyperpolarized (13)C-pyruvate in healthy subjects and prostate cancer patients. The study showed an elevated (13)C-lactate/(13)C-pyruvate ratio in regions of biopsy-proven prostate cancer compared to noncancerous tissue. However, more studies are needed in order to establish use......In recent years there has been an immense development of new targeted anti-cancer drugs. For practicing precision medicine, a sensitive method imaging for non-invasive, assessment of early treatment response and for assisting in developing new drugs is warranted. Magnetic Resonance Spectroscopy...

  15. Unambiguous assigning of the signals of the nuclear magnetic resonance spectra of {sup 1} H and {sup 13} C of monoterpenes using computational methods; Asignacion inequivoca de las senales del espectro de resonancia magnetica nuclear de {sup 1} H y {sup 13} C de monoterpenos empleando metodos computacionales

    Energy Technology Data Exchange (ETDEWEB)

    Cortes, F.; Cuevas, G.; Tenorio, J.; Rochin, A.L. [Universidad Nacional Autonoma de Mexico, Instituto de Quimica, A.P. 70213, 04510 Mexico D.F. (Mexico)

    2000-07-01

    Ab initio calculations, within the frame of Density Functional Theory were carried out on camphene and {alpha}-pinene. The {sup 1} H and {sup 13} C shifts were estimated according to the recently developed Sum-Over-States Density Functional Perturbation Theory (SOS-DFPT) as implemented in a modified deMon-KS program. The calculations not only reproduced the observed NMR chemical shifts, quantitatively in the case of {sup 1} H nuclei and qualitatively in the case of {sup 13} C nuclei, but also allow assigning unambiguously the signal on these spectra. (Author)

  16. MNDO/GIAO perturbation calculation of 13C and 19F magnetic shielding constants

    Institute of Scientific and Technical Information of China (English)

    游效曾; 吴伟雄; 方维海

    1995-01-01

    The basic approximation of the MNDO method is applied to the SCF-MO theory of nu-clear magnetic shielding constants.Gauge-invariant atomic orbitais(GIAO)and derived equations are used to cal-culate NMR chemical shifts.A more simple and effective calculation of integration for operators 1/rM,LM andLM/rM described in our previous paper is used.By proper selection of MNDO parameters together with thetwo-center approximation,a satisfactory agreement between computational and experimental 13C and 19F chemi-cal shifts is obtained for a representative set of fluorides.

  17. Construction and (13) C hyperpolarization efficiency of a 180 GHz dissolution dynamic nuclear polarization system.

    Science.gov (United States)

    Kiswandhi, Andhika; Niedbalski, Peter; Parish, Christopher; Ferguson, Sarah; Taylor, David; McDonald, George; Lumata, Lloyd

    2017-09-01

    Dynamic nuclear polarization (DNP) via the dissolution method has become one of the rapidly emerging techniques to alleviate the low signal sensitivity in nuclear magnetic resonance (NMR) spectroscopy and imaging. In this paper, we report on the development and (13) C hyperpolarization efficiency of a homebuilt DNP system operating at 6.423 T and 1.4 K. The DNP hyperpolarizer system was assembled on a wide-bore superconducting magnet, equipped with a standard continuous-flow cryostat, and a 180 GHz microwave source with 120 mW power output and wide 4 GHz frequency tuning range. At 6.423 T and 1.4 K, solid-state (13) C polarization P levels of 64% and 31% were achieved for 3 M [1-(13) C] sodium acetate samples in 1 : 1 v/v glycerol:water glassing matrix doped with 15 mM trityl OX063 and 40 mM 4-oxo-TEMPO, respectively. Upon dissolution, which takes about 15 s to complete, liquid-state (13) C NMR signal enhancements as high as 240 000-fold (P=21%) were recorded in a nearby high resolution (13) C NMR spectrometer at 1 T and 297 K. Considering the relatively lower cost of our homebuilt DNP system and the relative simplicity of its design, the dissolution DNP setup reported here could be feasibly adapted for in vitro or in vivo hyperpolarized (13) C NMR or magnetic resonance imaging at least in the pre-clinical setting. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  18. How Energy Metabolism Supports Cerebral Function: Insights from (13)C Magnetic Resonance Studies In vivo.

    Science.gov (United States)

    Sonnay, Sarah; Gruetter, Rolf; Duarte, João M N

    2017-01-01

    Cerebral function is associated with exceptionally high metabolic activity, and requires continuous supply of oxygen and nutrients from the blood stream. Since the mid-twentieth century the idea that brain energy metabolism is coupled to neuronal activity has emerged, and a number of studies supported this hypothesis. Moreover, brain energy metabolism was demonstrated to be compartmentalized in neurons and astrocytes, and astrocytic glycolysis was proposed to serve the energetic demands of glutamatergic activity. Shedding light on the role of astrocytes in brain metabolism, the earlier picture of astrocytes being restricted to a scaffold-associated function in the brain is now out of date. With the development and optimization of non-invasive techniques, such as nuclear magnetic resonance spectroscopy (MRS), several groups have worked on assessing cerebral metabolism in vivo. In this context, (1)H MRS has allowed the measurements of energy metabolism-related compounds, whose concentrations can vary under different brain activation states. (1)H-[(13)C] MRS, i.e., indirect detection of signals from (13)C-coupled (1)H, together with infusion of (13)C-enriched glucose has provided insights into the coupling between neurotransmission and glucose oxidation. Although these techniques tackle the coupling between neuronal activity and metabolism, they lack chemical specificity and fail in providing information on neuronal and glial metabolic pathways underlying those processes. Currently, the improvement of detection modalities (i.e., direct detection of (13)C isotopomers), the progress in building adequate mathematical models along with the increase in magnetic field strength now available render possible detailed compartmentalized metabolic flux characterization. In particular, direct (13)C MRS offers more detailed dataset acquisitions and provides information on metabolic interactions between neurons and astrocytes, and their role in supporting neurotransmission. Here

  19. How Energy Metabolism Supports Cerebral Function: Insights from 13C Magnetic Resonance Studies In vivo

    Directory of Open Access Journals (Sweden)

    Sarah Sonnay

    2017-05-01

    Full Text Available Cerebral function is associated with exceptionally high metabolic activity, and requires continuous supply of oxygen and nutrients from the blood stream. Since the mid-twentieth century the idea that brain energy metabolism is coupled to neuronal activity has emerged, and a number of studies supported this hypothesis. Moreover, brain energy metabolism was demonstrated to be compartmentalized in neurons and astrocytes, and astrocytic glycolysis was proposed to serve the energetic demands of glutamatergic activity. Shedding light on the role of astrocytes in brain metabolism, the earlier picture of astrocytes being restricted to a scaffold-associated function in the brain is now out of date. With the development and optimization of non-invasive techniques, such as nuclear magnetic resonance spectroscopy (MRS, several groups have worked on assessing cerebral metabolism in vivo. In this context, 1H MRS has allowed the measurements of energy metabolism-related compounds, whose concentrations can vary under different brain activation states. 1H-[13C] MRS, i.e., indirect detection of signals from 13C-coupled 1H, together with infusion of 13C-enriched glucose has provided insights into the coupling between neurotransmission and glucose oxidation. Although these techniques tackle the coupling between neuronal activity and metabolism, they lack chemical specificity and fail in providing information on neuronal and glial metabolic pathways underlying those processes. Currently, the improvement of detection modalities (i.e., direct detection of 13C isotopomers, the progress in building adequate mathematical models along with the increase in magnetic field strength now available render possible detailed compartmentalized metabolic flux characterization. In particular, direct 13C MRS offers more detailed dataset acquisitions and provides information on metabolic interactions between neurons and astrocytes, and their role in supporting neurotransmission. Here

  20. Real-time assessment of Krebs cycle metabolism using hyperpolarized 13C magnetic resonance spectroscopy.

    Science.gov (United States)

    Schroeder, Marie A; Atherton, Helen J; Ball, Daniel R; Cole, Mark A; Heather, Lisa C; Griffin, Julian L; Clarke, Kieran; Radda, George K; Tyler, Damian J

    2009-08-01

    The Krebs cycle plays a fundamental role in cardiac energy production and is often implicated in the energetic imbalance characteristic of heart disease. In this study, we measured Krebs cycle flux in real time in perfused rat hearts using hyperpolarized magnetic resonance spectroscopy (MRS). [2-(13)C]Pyruvate was hyperpolarized and infused into isolated perfused hearts in both healthy and postischemic metabolic states. We followed the enzymatic conversion of pyruvate to lactate, acetylcarnitine, citrate, and glutamate with 1 s temporal resolution. The appearance of (13)C-labeled glutamate was delayed compared with that of other metabolites, indicating that Krebs cycle flux can be measured directly. The production of (13)C-labeled citrate and glutamate was decreased postischemia, as opposed to lactate, which was significantly elevated. These results showed that the control and fluxes of the Krebs cycle in heart disease can be studied using hyperpolarized [2-(13)C]pyruvate.

  1. Sensitive {sup 13}C-{sup 13}C correlation spectra of amyloid fibrils at very high spinning frequencies and magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Weingarth, Markus [Utrecht University (Netherlands); Masuda, Yuichi; Takegoshi, K. [Kyoto University, Department of Chemistry, Graduate School of Science (Japan); Bodenhausen, Geoffrey; Tekely, Piotr, E-mail: piotr.tekely@ens.fr [Ecole Normale Superieure, Departement de Chimie (France)

    2011-06-15

    Sensitive 2D solid-state {sup 13}C-{sup 13}C correlation spectra of amyloid {beta} fibrils have been recorded at very fast spinning frequencies and very high magnetic fields. It is demonstrated that PARIS-xy recoupling using moderate rf amplitudes can provide structural information by promoting efficient magnetization transfer even under such challenging experimental conditions. Furthermore, it has been shown both experimentally and by numerical simulations that the method is not very sensitive to dipolar truncation effects and can reveal direct transfer across distances of about 3.5-4A.

  2. The truncated driven NOE and 13C NMR sensitivity enhancement in magnetically-aligned bicelles

    Science.gov (United States)

    Macdonald, Peter M.; Soong, Ronald

    2007-09-01

    The truncated driven nuclear Overhauser effect (NOE) sequence is examined as a means of sensitivity enhancement in 13C NMR spectroscopy of magnetically-aligned bicelles consisting of 4.5:1 mixtures of DMPC (1,2-dimyristoyl- sn-glycero-3-phosphocholine) plus DHPC (1,2-dihexanoyl- sn-glycero-3-phosphocholine), with 1 mole% DMPE-PEG 2000 (1,2-dimyristoyl- sn-glycero-3-phosphoethanolamine- N-methoxy(polyethylene glycol)-2000). Steady-state NOE enhancements were observed at all carbon segments except the lipid carbonyls, but full NOE enhancements were obtained only for the most mobile carbon segments, specifically the choline quaternary methyls and terminal acyl chain methyls of both DMPC and DHPC, as well as the ethylene oxide segments of the PEG head group of DMPE-PEG 2000. Other carbon segments exhibited NOE enhancements that scaled with mobility as determined by transient NOE measurements combined with spin-lattice relaxation measurements. We conclude that the truncated driven NOE provides sensitivity enhancement complimentary to that yielded by cross-polarization techniques and for mobile membrane-associated species may be preferred for its robustness and ease of setup.

  3. The truncated driven NOE and (13)C NMR sensitivity enhancement in magnetically-aligned bicelles.

    Science.gov (United States)

    Macdonald, Peter M; Soong, Ronald

    2007-09-01

    The truncated driven nuclear Overhauser effect (NOE) sequence is examined as a means of sensitivity enhancement in (13)C NMR spectroscopy of magnetically-aligned bicelles consisting of 4.5:1 mixtures of DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) plus DHPC (1,2-dihexanoyl-sn-glycero-3-phosphocholine), with 1 mole% DMPE-PEG 2000 (1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine-N-methoxy(polyethylene glycol)-2000). Steady-state NOE enhancements were observed at all carbon segments except the lipid carbonyls, but full NOE enhancements were obtained only for the most mobile carbon segments, specifically the choline quaternary methyls and terminal acyl chain methyls of both DMPC and DHPC, as well as the ethylene oxide segments of the PEG head group of DMPE-PEG 2000. Other carbon segments exhibited NOE enhancements that scaled with mobility as determined by transient NOE measurements combined with spin-lattice relaxation measurements. We conclude that the truncated driven NOE provides sensitivity enhancement complimentary to that yielded by cross-polarization techniques and for mobile membrane-associated species may be preferred for its robustness and ease of setup.

  4. HYPERPOLARIZED 13C MAGNETIC RESONANCE AND ITS USE IN METABOLIC ASSESSMENT OF CULTURED CELLS AND PERFUSED ORGANS

    Science.gov (United States)

    Lumata, Lloyd; Yang, Chendong; Ragavan, Mukundan; Carpenter, Nicholas; DeBerardinis, Ralph J.; Merritt, Matthew E.

    2016-01-01

    Diseased tissue is often characterized by abnormalities in intermediary metabolism. Observing these alterations in situ may lead to an improved understanding of pathological processes and novel ways to monitor these processes non-invasively in human patients. Although 13C is a stable isotope safe for use in animal models of disease as well as human subjects, its utility as a metabolic tracer has largely been limited to ex vivo analyses employing analytical techniques like mass spectrometry or nuclear magnetic resonance spectroscopy. Neither of these techniques is suitable for non-invasive metabolic monitoring, and the low abundance and poor gyromagnetic ratio of conventional 13C make it a poor nucleus for imaging. However, the recent advent of hyperpolarization methods, particularly dynamic nuclear polarization (DNP), make it possible to enhance the spin polarization state of 13C by many orders of magnitude, resulting in a temporary amplification of the signal sufficient for monitoring kinetics of enzyme-catalyzed reactions in living tissue through magnetic resonance spectroscopy or magnetic resonance imaging. Here we review DNP techniques to monitor metabolism in cultured cells, perfused hearts, and perfused livers, focusing on our experiences with hyperpolarized [1-13C]pyruvate. We present detailed approaches to optimize the DNP procedure, streamline biological sample preparation, and maximize detection of specific metabolic activities. We also discuss practical aspects in the choice of metabolic substrates for hyperpolarization studies, and outline some of the current technical and conceptual challenges in the field, including efforts to use hyperpolarization to quantify metabolic rates in vivo. PMID:26358902

  5. Antiferromagnetic nuclear spin helix and topological superconductivity in 13C nanotubes

    Science.gov (United States)

    Hsu, Chen-Hsuan; Stano, Peter; Klinovaja, Jelena; Loss, Daniel

    2015-12-01

    We investigate the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction arising from the hyperfine coupling between localized nuclear spins and conduction electrons in interacting 13C carbon nanotubes. Using the Luttinger liquid formalism, we show that the RKKY interaction is sublattice dependent, consistent with the spin susceptibility calculation in noninteracting carbon nanotubes, and it leads to an antiferromagnetic nuclear spin helix in finite-size systems. The transition temperature reaches up to tens of mK, due to a strong boost by a positive feedback through the Overhauser field from ordered nuclear spins. Similar to GaAs nanowires, the formation of the helical nuclear spin order gaps out half of the conduction electrons, and is therefore observable as a reduction of conductance by a factor of 2 in a transport experiment. The nuclear spin helix leads to a density wave combining spin and charge degrees of freedom in the electron subsystem, resulting in synthetic spin-orbit interaction, which induces nontrivial topological phases. As a result, topological superconductivity with Majorana fermion bound states can be realized in the system in the presence of proximity-induced superconductivity without the need of fine tuning the chemical potential. We present the phase diagram as a function of system parameters, including the pairing gaps, the gap due to the nuclear spin helix, and the Zeeman field perpendicular to the helical plane.

  6. 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.

    Science.gov (United States)

    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

  7. 13C Mrs Studies of the Control of Hepatic Glycogen Metabolism at High Magnetic Fields

    Science.gov (United States)

    Miller, Corin O.; Cao, Jin; Zhu, He; Chen, Li M.; Wilson, George; Kennan, Richard; Gore, John C.

    2017-06-01

    and induction of glycogen breakdown. In the perfused liver, inclusion of insulin was able to dose-dependently block the effect of glucagon. Conclusion: Hepatic glycogen synthesis, as well as acute hormonally-induced changes thereof, can be measured using 13C MRS at high magnetic fields both ex-vivo

  8. Relayed 13C magnetization transfer: Detection of malate dehydrogenase reaction in vivo

    Science.gov (United States)

    Yang, Jehoon; Shen, Jun

    2007-02-01

    Malate dehydrogenase catalyzes rapid interconversion between dilute metabolites oxaloacetate and malate. Both oxaloacetate and malate are below the detection threshold of in vivo MRS. Oxaloacetate is also in rapid exchange with aspartate catalyzed by aspartate aminotransferase, the latter metabolite is observable in vivo using 13C MRS. We hypothesized that the rapid turnover of oxaloacetate can effectively relay perturbation of magnetization between malate and aspartate. Here, we report indirect observation of the malate dehydrogenase reaction by saturating malate C2 resonance at 71.2 ppm and detecting a reduced aspartate C2 signal at 53.2 ppm due to relayed magnetization transfer via oxaloacetate C2 at 201.3 ppm. Using this strategy the rate of the cerebral malate dehydrogenase reaction was determined to be 9 ± 2 μmol/g wet weight/min (means ± SD, n = 5) at 11.7 Tesla in anesthetized adult rats infused with [1,6- 13C 2]glucose.

  9. Imaging cerebral 2-ketoisocaproate metabolism with hyperpolarized (13)C Magnetic Resonance Spectroscopic Imaging

    DEFF Research Database (Denmark)

    Butt, Sadia Asghar; Søgaard, Lise Vejby-Christensen; Magnusson, Peter O.

    2012-01-01

    The branched chain amino acid transaminase (BCAT) has an important role in nitrogen shuttling and glutamate metabolism in the brain. The purpose of this study was to describe the cerebral distribution and metabolism of hyperpolarized 2-keto[1-(13)C]isocaproate (KIC) in the normal rat using magnet...... & Metabolism advance online publication, 28 March 2012; doi:10.1038/jcbfm.2012.34....

  10. Real-time assessment of Krebs cycle metabolism using hyperpolarized 13C magnetic resonance spectroscopy

    OpenAIRE

    Schroeder, Marie A.; Atherton, Helen J; Ball, Daniel R.; Cole, Mark A.; Heather, Lisa C.; Griffin, Julian L; Clarke, Kieran; Radda, George K.; Tyler, Damian J

    2009-01-01

    The Krebs cycle plays a fundamental role in cardiac energy production and is often implicated in the energetic imbalance characteristic of heart disease. In this study, we measured Krebs cycle flux in real time in perfused rat hearts using hyperpolarized magnetic resonance spectroscopy (MRS). [2-13C]Pyruvate was hyperpolarized and infused into isolated perfused hearts in both healthy and postischemic metabolic states. We followed the enzymatic conversion of pyruvate to lactate, acetylcarnitin...

  11. Real-time assessment of Krebs cycle metabolism using hyperpolarized 13C magnetic resonance spectroscopy

    OpenAIRE

    Schroeder, Marie A; Atherton, Helen J.; Ball, Daniel R.; Cole, Mark A; Heather, Lisa C.; Griffin, Julian L.; Clarke, Kieran; Radda, George K; Tyler, Damian J.

    2009-01-01

    The Krebs cycle plays a fundamental role in cardiac energy production and is often implicated in the energetic imbalance characteristic of heart disease. In this study, we measured Krebs cycle flux in real time in perfused rat hearts using hyperpolarized magnetic resonance spectroscopy (MRS). [2-13C]Pyruvate was hyperpolarized and infused into isolated perfused hearts in both healthy and postischemic metabolic states. We followed the enzymatic conversion of pyruvate to lactate, acetylcarnitin...

  12. Assessing Oxidative Stress in Tumors by Measuring the Rate of Hyperpolarized [1-13C]Dehydroascorbic Acid Reduction Using 13C Magnetic Resonance Spectroscopy*

    Science.gov (United States)

    Timm, Kerstin N.; Hu, De-En; Williams, Michael; Wright, Alan J.; Kettunen, Mikko I.; Kennedy, Brett W. C.; Larkin, Timothy J.; Dzien, Piotr; Marco-Rius, Irene; Bohndiek, Sarah E.; Brindle, Kevin M.

    2017-01-01

    Rapid cancer cell proliferation promotes the production of reducing equivalents, which counteract the effects of relatively high levels of reactive oxygen species. Reactive oxygen species levels increase in response to chemotherapy and cell death, whereas an increase in antioxidant capacity can confer resistance to chemotherapy and is associated with an aggressive tumor phenotype. The pentose phosphate pathway is a major site of NADPH production in the cell, which is used to maintain the main intracellular antioxidant, glutathione, in its reduced state. Previous studies have shown that the rate of hyperpolarized [1-13C]dehydroascorbic acid (DHA) reduction, which can be measured in vivo using non-invasive 13C magnetic resonance spectroscopic imaging, is increased in tumors and that this is correlated with the levels of reduced glutathione. We show here that the rate of hyperpolarized [1-13C]DHA reduction is increased in tumors that have been oxidatively prestressed by depleting the glutathione pool by buthionine sulfoximine treatment. This increase was associated with a corresponding increase in pentose phosphate pathway flux, assessed using 13C-labeled glucose, and an increase in glutaredoxin activity, which catalyzes the glutathione-dependent reduction of DHA. These results show that the rate of DHA reduction depends not only on the level of reduced glutathione, but also on the rate of NADPH production, contradicting the conclusions of some previous studies. Hyperpolarized [1-13C]DHA can be used, therefore, to assess the capacity of tumor cells to resist oxidative stress in vivo. However, DHA administration resulted in transient respiratory arrest and cardiac depression, which may prevent translation to the clinic. PMID:27994059

  13. Determination of 13C/ 12C ratios with (d, p) nuclear reactions

    Science.gov (United States)

    Wang, Y. Q.; Zhang, J.; Tesmer, J. R.; Li, Y. H.; Greco, R.; Grim, G. P.; Obst, A. W.; Rundberg, R. S.; Wilhelmy, J. B.

    2010-06-01

    Stable isotope ratios such as 13C/ 12C play an important role in many applications including environment and energy research. Since many surface analysis techniques are plagued with unavoidable hydrocarbon contamination issues during analysis, it is highly desirable that 13C and 12C isotopes be measured simultaneously especially in specimens with a minute amount of 13C, in order to reliably determine 13C/ 12C ratios. In this paper, we report that deuterium induced proton particle reactions, 13C(d, p) 14C and 12C(d, p) 13C, provide a convenient and reliable approach for 13C/ 12C ratio determination. Optimizations on experimental considerations and potential interferences from other common light isotopes are discussed as well as results from the application of this technique to diagnose the performance of a target debris collection in an inertial confinement fusion (ICF) experiment.

  14. A polymer-based magnetic resonance tracer for visualization of solid tumors by 13C spectroscopic imaging.

    Directory of Open Access Journals (Sweden)

    Yoshikazu Suzuki

    Full Text Available Morphological imaging precedes lesion-specific visualization in magnetic resonance imaging (MRI because of the superior ability of this technique to depict tissue morphology with excellent spatial and temporal resolutions. To achieve lesion-specific visualization of tumors by MRI, we investigated the availability of a novel polymer-based tracer. Although the 13C nucleus is a candidate for a detection nucleus because of its low background signal in the body, the low magnetic resonance sensitivity of the nucleus needs to be resolved before developing a 13C-based tracer. In order to overcome this problem, we enriched polyethylene glycol (PEG, a biocompatible polymer, with 13C atoms. 13C-PEG40,000 (13C-PEG with an average molecular weight of 40 kDa emitted a single 13C signal with a high signal-to-noise ratio due to its ability to maintain signal sharpness, as was confirmed by in vivo investigation, and displayed a chemical shift sufficiently distinct from that of endogenous fat. 13C-PEG40,000 intravenously injected into mice showed long retention in circulation, leading to its effective accumulation in tumors reflecting the well-known phenomenon that macromolecules accumulate in tumors because of leaky tumor capillaries. These properties of 13C-PEG40,000 allowed visualization of tumors in mice by 13C spectroscopic imaging. These findings suggest that a technique based on 13C-PEG is a promising strategy for tumor detection.

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

    Science.gov (United States)

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

    2015-02-01

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

  16. The use of dynamic nuclear polarization 13C-pyruvate MRS in cancer

    DEFF Research Database (Denmark)

    Borgwardt, Henrik Gutte; Espe Hansen, Adam; Hjort Johannesen, Helle;

    2015-01-01

    In recent years there has been an immense development of new targeted anti-cancer drugs. For practicing precision medicine, a sensitive method imaging for non-invasive, assessment of early treatment response and for assisting in developing new drugs is warranted. Magnetic Resonance Spectroscopy...... (MRS) is a potent technique for non-invasive in vivo investigation of tissue chemistry and cellular metabolism. Hyperpolarization by Dynamic Nuclear Polarization (DNP) is capable of creating solutions of molecules with polarized nuclear spins in a range of biological molecules and has enabled the real......-time investigation of in vivo metabolism. The development of this new method has been demonstrated to enhance the nuclear polarization more than 10,000-fold, thereby significantly increasing the sensitivity of the MRS with a spatial resolution to the millimeters and a temporal resolution at the subsecond range...

  17. Determination of {sup 13}C/{sup 12}C ratios with (d, p) nuclear reactions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.Q., E-mail: yqwang@lanl.go [Materials Science and Technology Division, Los Alamos National Laboratory, NM 87544 (United States); Zhang, J. [Materials Science and Technology Division, Los Alamos National Laboratory, NM 87544 (United States); School of Nuclear Science and Technology, Lanzhou University, Gansu 730000 (China); Tesmer, J.R. [Materials Science and Technology Division, Los Alamos National Laboratory, NM 87544 (United States); Li, Y.H. [Materials Science and Technology Division, Los Alamos National Laboratory, NM 87544 (United States); School of Nuclear Science and Technology, Lanzhou University, Gansu 730000 (China); Greco, R. [Materials Science and Technology Division, Los Alamos National Laboratory, NM 87544 (United States); Grim, G.P.; Obst, A.W. [Physics Division, Los Alamos National Laboratory, NM 87544 (United States); Rundberg, R.S.; Wilhelmy, J.B. [Chemistry Division, Los Alamos National Laboratory, NM 87544 (United States)

    2010-06-15

    Stable isotope ratios such as {sup 13}C/{sup 12}C play an important role in many applications including environment and energy research. Since many surface analysis techniques are plagued with unavoidable hydrocarbon contamination issues during analysis, it is highly desirable that {sup 13}C and {sup 12}C isotopes be measured simultaneously especially in specimens with a minute amount of {sup 13}C, in order to reliably determine {sup 13}C/{sup 12}C ratios. In this paper, we report that deuterium induced proton particle reactions, {sup 13}C(d, p){sup 14}C and {sup 12}C(d, p){sup 13}C, provide a convenient and reliable approach for {sup 13}C/{sup 12}C ratio determination. Optimizations on experimental considerations and potential interferences from other common light isotopes are discussed as well as results from the application of this technique to diagnose the performance of a target debris collection in an inertial confinement fusion (ICF) experiment.

  18. Assessment of Hepatic Mitochondrial Oxidation and Pyruvate Cycling in NAFLD by (13)C Magnetic Resonance Spectroscopy

    DEFF Research Database (Denmark)

    Petersen, Kitt Mia Falck; Befroy, Douglas E; Dufour, Sylvie

    2016-01-01

    Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, and there is great interest in understanding the potential role of alterations in mitochondrial metabolism in its pathogenesis. To address this question, we assessed rates of hepatic mitochondrial oxidation...... in subjects with and without NAFLD by monitoring the rate of (13)C labeling in hepatic [5-(13)C]glutamate and [1-(13)C]glutamate by (13)C MRS during an infusion of [1-(13)C]acetate. We found that rates of hepatic mitochondrial oxidation were similar between NAFLD and control subjects. We also assessed rates...

  19. Detecting response of rat C6 glioma tumors to radiotherapy using hyperpolarized [1-13C]pyruvate and 13C magnetic resonance spectroscopic imaging

    OpenAIRE

    Day, Sam E.; Kettunen, Mikko I.; Cherkuri, Murali Krishna; James B Mitchell; Lizak, Martin J.; Morris, H. Douglas; Koretsky, Alan P.; Brindle, Kevin M.

    2010-01-01

    13C chemical shift images acquired following intravenous injection of hyperpolarized [1-13C]pyruvate into rats with implanted C6 gliomas showed significant labeling of lactate within the tumors but not in surrounding brain tissue. Signal from pyruvate was observed in blood vessels above the brain and from other major vessels elsewhere in the rat head. Pyruvate was largely undetectable within the tumor or surrounding normal brain tissue. The ratio of hyperpolarized 13C label in the injected py...

  20. Characterization of hyperfine interaction between an NV electron spin and a first-shell 13C nuclear spin in diamond

    Science.gov (United States)

    Rao, K. Rama Koteswara; Suter, Dieter

    2016-08-01

    The nitrogen-vacancy (NV) center in diamond has attractive properties for a number of quantum technologies that rely on the spin angular momentum of the electron and the nuclei adjacent to the center. The nucleus with the strongest interaction is the 13C nuclear spin of the first shell. Using this degree of freedom effectively hinges on precise data on the hyperfine interaction between the electronic and the nuclear spin. Here, we present detailed experimental data on this interaction, together with an analysis that yields all parameters of the hyperfine tensor, as well as its orientation with respect to the atomic structure of the center.

  1. Relativistic Force Field: Parametrization of (13)C-(1)H Nuclear Spin-Spin Coupling Constants.

    Science.gov (United States)

    Kutateladze, Andrei G; Mukhina, Olga A

    2015-11-01

    Previously, we reported a reliable DU8 method for natural bond orbital (NBO)-aided parametric scaling of Fermi contacts to achieve fast and accurate prediction of proton-proton spin-spin coupling constants (SSCC) in (1)H NMR. As sophisticated NMR experiments for precise measurements of carbon-proton SSCCs are becoming more user-friendly and broadly utilized by the organic chemistry community to guide and inform the process of structure determination of complex organic compounds, we have now developed a fast and accurate method for computing (13)C-(1)H SSCCs. Fermi contacts computed with the DU8 basis set are scaled using selected NBO parameters in conjunction with empirical scaling coefficients. The method is optimized for inexpensive B3LYP/6-31G(d) geometries. The parametric scaling is based on a carefully selected training set of 274 ((3)J), 193 ((2)J), and 143 ((1)J) experimental (13)C-(1)H spin-spin coupling constants reported in the literature. The DU8 basis set, optimized for computing Fermi contacts, which by design had evolved from optimization of a collection of inexpensive 3-21G*, 4-21G, and 6-31G(d) bases, offers very short computational (wall) times even for relatively large organic molecules containing 15-20 carbon atoms. The most informative SSCCs for structure determination, i.e., (3)J, were computed with an accuracy of 0.41 Hz (rmsd). The new unified approach for computing (1)H-(1)H and (13)C-(1)H SSCCs is termed "DU8c".

  2. Effect of burn injury on relative anaplerosis and gluconeogenesis in rats by 13C magnetic resonance spectrum

    Institute of Scientific and Technical Information of China (English)

    夏照帆; 田建广; 王光毅; 葛绳德; 唐洪泰

    2002-01-01

    Objective: To introduce a safe and specific approachof 13C magnetic resonance spectrum (13C MRS )spectroscopy and investigate the alterations in hepaticanabolism.Methods: Relative anaplerotic, pyruvate recyclingand gluconeogenic fluxes were measured by 13C MRSisotopomer analysis of blood glucose from rats with 40%body surface area burn injury, and from rats exposed tosham injury. A short chain fatty acid, [U-13C] propionatewhich was avidly extracted by the liver, was infusedintravenously to deliver 13C into the citric acid cycle.Proton-decoupled 13C MRS of deproteinized plasma orextracts of the freeze-clamped liver were used to determinethe distribution of 13C in blood or hepatic glucose.Results: There was no difference in the multipletsdetected in the glucose carbon-2 anomer from blood or liverafter 45 or 60 minutes of the infusion of the propionate,indicating that steady-state isotopic conditions wereachieved. Gluconeogenesis relative to citric acid cycle fluxwas not altered by burn injury; in both sham and burngroups the rate of glucose production was about equal toflux through citrate synthase. In the sham group ofanimals, the rate of entry of carbon skeletons into the citricacid cycle was about 4 times than that in the burn group.Similarly, flux through pyruvate kinase (again relative tocitrate synthase) was significantly increased after the burninjury.Conclusions: Since results from analysis of the bloodglucose are the same as that of the hepatic glucose, 13Cdistribution in the glucose and hepatic metabolism can beassessed based on the 13C MRS analysis of the bloodglucose.

  3. Model free approach to kinetic analysis of real-time hyperpolarized 13C magnetic resonance spectroscopy data.

    Directory of Open Access Journals (Sweden)

    Deborah K Hill

    Full Text Available Real-time detection of the rates of metabolic flux, or exchange rates of endogenous enzymatic reactions, is now feasible in biological systems using Dynamic Nuclear Polarization Magnetic Resonance. Derivation of reaction rate kinetics from this technique typically requires multi-compartmental modeling of dynamic data, and results are therefore model-dependent and prone to misinterpretation. We present a model-free formulism based on the ratio of total areas under the curve (AUC of the injected and product metabolite, for example pyruvate and lactate. A theoretical framework to support this novel analysis approach is described, and demonstrates that the AUC ratio is proportional to the forward rate constant k. We show that the model-free approach strongly correlates with k for whole cell in vitro experiments across a range of cancer cell lines, and detects response in cells treated with the pan-class I PI3K inhibitor GDC-0941 with comparable or greater sensitivity. The same result is seen in vivo with tumor xenograft-bearing mice, in control tumors and following drug treatment with dichloroacetate. An important finding is that the area under the curve is independent of both the input function and of any other metabolic pathways arising from the injected metabolite. This model-free approach provides a robust and clinically relevant alternative to kinetic model-based rate measurements in the clinical translation of hyperpolarized (13C metabolic imaging in humans, where measurement of the input function can be problematic.

  4. High Field In vivo13C Magnetic Resonance Spectroscopy of Brain by Random Radiofrequency Heteronuclear Decoupling and Data Undersampling

    Directory of Open Access Journals (Sweden)

    Ningzhi Li

    2017-06-01

    Full Text Available In vivo13C magnetic resonance spectroscopy (MRS is a unique and effective tool for studying dynamic human brain metabolism and the cycling of neurotransmitters. One of the major technical challenges for in vivo13C-MRS is the high radio frequency (RF power necessary for heteronuclear decoupling. In the common practice of in vivo13C-MRS, alkanyl carbons are detected in the spectra range of 10–65 ppm. The amplitude of decoupling pulses has to be significantly greater than the large one-bond 1H-13C scalar coupling (1JCH = 125–145 Hz. Two main proton decoupling methods have been developed: broadband stochastic decoupling and coherent composite or adiabatic pulse decoupling (e.g., WALTZ; the latter is widely used because of its efficiency and superb performance under inhomogeneous B1 field. Because the RF power required for proton decoupling increases quadratically with field strength, in vivo13C-MRS using coherent decoupling is often limited to low magnetic fields [<=4 Tesla (T] to keep the local and averaged specific absorption rate (SAR under the safety guidelines established by the International Electrotechnical Commission (IEC and the US Food and Drug Administration (FDA. Alternately, carboxylic/amide carbons are coupled to protons via weak long-range 1H-13C scalar couplings, which can be decoupled using low RF power broadband stochastic decoupling. Recently, the carboxylic/amide 13C-MRS technique using low power random RF heteronuclear decoupling was safely applied to human brain studies at 7T. Here, we review the two major decoupling methods and the carboxylic/amide 13C-MRS with low power decoupling strategy. Further decreases in RF power deposition by frequency-domain windowing and time-domain random under-sampling are also discussed. Low RF power decoupling opens the possibility of performing in vivo13C experiments of human brain at very high magnetic fields (such as 11.7T, where signal-to-noise ratio as well as spatial and temporal

  5. The use of dynamic nuclear polarization (13)C-pyruvate MRS in cancer

    DEFF Research Database (Denmark)

    Gutte, Henrik; Hansen, Adam Espe; Johannesen, Helle Hjorth

    2015-01-01

    (MRS) is a potent technique for non-invasive in vivo investigation of tissue chemistry and cellular metabolism. Hyperpolarization by Dynamic Nuclear Polarization (DNP) is capable of creating solutions of molecules with polarized nuclear spins in a range of biological molecules and has enabled the real......-time investigation of in vivo metabolism. The development of this new method has been demonstrated to enhance the nuclear polarization more than 10,000-fold, thereby significantly increasing the sensitivity of the MRS with a spatial resolution to the millimeters and a temporal resolution at the subsecond range...

  6. Electron-nuclear interaction in 13C nanotube double quantum dots

    DEFF Research Database (Denmark)

    Churchill, H O H; Bestwick, A J; Harlow, J W;

    2009-01-01

    For coherent electron spins, hyperfine coupling to nuclei in the host material can either be a dominant source of unwanted spin decoherence or, if controlled effectively, a resource enabling storage and retrieval of quantum information. To investigate the effect of a controllable nuclear environm...

  7. Carbon isotopic composition (δ(13)C and (14)C activity) of plant samples in the vicinity of the Slovene nuclear power plant.

    Science.gov (United States)

    Sturm, Martina; Vreča, Polona; Krajcar Bronić, Ines

    2012-08-01

    δ(13)C values of various plants (apples, wheat, and maize) collected in the vicinity of the Krško Nuclear Power Plant (Slovenia) during 2008 and 2009 were determined. By measuring dried samples and their carbonized counterparts we showed that no significant isotopic fractionation occurs during the carbonization phase of the sample preparation process in the laboratory. The measured δ(13)C values of the plants were used for δ(13)C correction of their measured (14)C activities.

  8. Characterization of Biochar by X-Ray Photoelectron Spectroscopy and 13 C Nuclear Magnetic Resonance%X射线光电子能谱与13 C核磁共振在生物质碳表征中的应用

    Institute of Scientific and Technical Information of China (English)

    徐东昱; 金洁; 颜钰; 韩兰芳; 康明洁; 王子莹; 赵烨; 孙可

    2014-01-01

    近年来,生物质碳(biochar)作为新型吸附剂被广泛研究。但由于制备biochar的生物质原料和热解温度的不同,使biochar的结构和组成存在差异,从而影响其对污染物的吸附。目前关于biochar的结构和组成的研究还不够全面。因此,结合了能谱与光谱分析的手段,对biochar的结构和组成进行了深入的分析。选取木质类(柳树枝条)和草类(水稻秸秆)作为原料,分别在不同热解温度(300,450和600℃)下制得bio-chars,并对biochars样品进行元素分析、X射线光电子能谱分析(XPS)和固态13C核磁共振(13CNMR)研究,以阐明不同热解温度和生物质来源的biochars的结构和组成。结果显示:biochar的H/C,O/C和(O+N)/C的比值随着热解温度的升高而降低;草类biochar比木质类biochar具有更高的灰分含量和表面极性;木质类biochar的矿物主要分布在样品颗粒内部,其表面被有机质覆盖,而草类biochar部分矿物暴露在样品颗粒表面;13CNMR显示低温制得的biochar主要由芳香碳、脂肪碳、羧基和羰基碳组成,高温制得的biochar主要由芳香碳组成,且低温制得biochars中,木质类biochars比草类biochars含有更高的木质素的残留碳结构,这是由于木质类biochars原材料中含有更高的木质素。%The wood (willow branch) and grass (rice straw ) materials were pyrolyzed at different temperatures (300 ,450 and 600 ℃) to obtain the biochars used in the present study .The biochars were characterized using elementary analysis ,X-ray pho-toelectron spectroscopy (XPS) and solid state 13 C cross-polarization and magic angle spinning nuclear magnetic resonance spec-troscopy (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

  9. Electron-nuclear interaction in 13C nanotube double quantum dots

    OpenAIRE

    Churchill, Hugh Olen Hill; Bestwick, Andrew J.; Harlow, Jennifer W.; Kuemmeth, Ferdinand; Marcos, David; Stwertka, Carolyn H.; Watson, Susan K.; Marcus, Charles Masamed

    2008-01-01

    For coherent electron spins, hyperfine coupling to nuclei in the host material can either be a dominant source of unwanted spin decoherence or, if controlled effectively, a resource allowing storage and retrieval of quantum information. To investigate the effect of a controllable nuclear environment on the evolution of confined electron spins, we have fabricated and measured gate-defined double quantum dots with integrated charge sensors made from single-walled carbon nanotubes with a variabl...

  10. Landmarks in the application of 13C-magnetic resonance spectroscopy to studies of neuronal/glial relationships.

    Science.gov (United States)

    Bachelard, H

    1998-01-01

    The development of the use of carbon isotopes as metabolic tracers is briefly described. 13C-labelled precursors (13CO2, 13CH4) first became available in 1940 and were studied in microorganisms, but their use was limited by very low enrichments and lack of suitable analytical equipment. More success was achieved with 11C and especially 14C, as these radioactive tracers did not need to be highly enriched. Although the stable 13C isotope can be used at a low percentage enrichment in mass spectrometry, its application to magnetic resonance spectroscopy (MRS) requires very highly enriched precursors, due to its low natural abundance and low sensitivity. Despite such limitations, however, the great advantage of 13C-MRS lies in its exquisite chemical specificity, in that labelling of different carbon atoms can be distinguished within the same molecule. Effective exploitation became feasible in the early 1970s with the advent of stable instruments, Fourier transform 13C-MRS, and the availability of highly enriched precursors. Reports of its use in brain research began to appear in the mid-1980s. The applications of 13C isotopomer analysis to research on neuronal/glial relationships are reviewed. The presence of neighbouring 13C-labelled atoms affects the appearance of the resonances (splitting due to C-C coupling), and so allows for unique quantification of rates through different and possibly competing pathways. Isotopomer patterns in resonances labelled from a combination of [1-13C]glucose and [1, 2-13C2]acetate have revealed aspects of neuronal/glial metabolic trafficking on depolarization and under hypoxic conditions in vitro. This approach has now been applied to in vivo studies on inhibition of glial metabolism using fluoroacetate. The results confirm the glial specificity of the toxin and demonstrate that it does not affect entry of acetate. When the glial TCA cycle is inhibited, the ability of the glia to participate in the glutamate/glutamine cycle remains

  11. Magnetic resonance butterfly coils: Design and application for hyperpolarized 13C studies

    DEFF Research Database (Denmark)

    Giovannetti, Giulio; Frijia, Francesca; Attanasio, Simona

    2013-01-01

    of dedicated coils capable of providing large field of view with high Signal-to-Noise Ratio (SNR) data is of fundamental importance. This work presents magnetostatic simulations and tests of two butterfly coils with different geometries, both designed for 13C hyperpolarized studies of pig heart with a clinical...... 3T scanner. In particular, the paper provides details of the design, modeling, construction and application of the butterfly style coils. While both coils could be successfully employed in single configuration (linear mode), the second prototype was used to design a quadrature surface coil...... constituted by the butterfly and a circular loop both in receive (RX) mode while using a birdcage coil as transmitter (TX). The performance of this coils configuration was compared with the single TX/RX birdcage coil, in order to verify the advantage of the proposed configuration over the volume coil...

  12. Tunable 13C/1H dual channel matching circuit for dynamic nuclear polarization system with cross-polarization

    DEFF Research Database (Denmark)

    Rybalko, Oleksandr; Bowen, Sean; Zhurbenko, Vitaliy

    2016-01-01

    In this paper we report initial results of design and practical implementation of tuning and matching circuit to estimate a performance of Dynamic Nuclear Polarization (DNP) at a magnetic field of 6.7 T. It is shown that developed circuit for signal observation is compact, easy to make and provides...

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

    Science.gov (United States)

    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...

  14. Tricarboxylic acid cycle activity measured by 13C magnetic resonance spectroscopy in rats subjected to the kaolin model of obstructed hydrocephalus

    DEFF Research Database (Denmark)

    Melø, Torun M; Håberg, Asta K; Risa, Øystein

    2011-01-01

    weeks after rats were subjected to kaolin-induced progressive hydrocephalus. In vivo and ex vivo magnetic resonance spectroscopy (MRS), combined with the infusion of [1,6-(13)C]glucose, was used to monitor the time courses of (13)C label incorporation into the different carbon positions of glutamate...

  15. Efficiency evaluation of a 13C Magnetic Resonance birdcage coil: Theory and comparison of four methods

    DEFF Research Database (Denmark)

    Giovannetti, Giulio; Frijia, Francesca; Hartwig, Valentina;

    2013-01-01

    .Coil efficiency, defined as the B1 magnetic field induced at a given point on the square root of supplied power P, is an important parameter that characterizes coil performance, since by maximizing efficiency will also maximize the signal-to-noise ratio.This work describes and compares four methods for coil...... efficiency estimation, based on different theoretical approaches. Three methods allow efficiency measurement by using “probe techniques” (perturbing loop, perturbing sphere and pick-up coil), which can be used both on the bench and inside the scanner, while an “NMR technique” has been employed for comparison...

  16. Evaluation of heterogeneous metabolic profile in an orthotopic human glioblastoma xenograft model using compressed sensing hyperpolarized 3D 13C magnetic resonance spectroscopic imaging.

    Science.gov (United States)

    Park, Ilwoo; Hu, Simon; Bok, Robert; Ozawa, Tomoko; Ito, Motokazu; Mukherjee, Joydeep; Phillips, Joanna J; James, C David; Pieper, Russell O; Ronen, Sabrina M; Vigneron, Daniel B; Nelson, Sarah J

    2013-07-01

    High resolution compressed sensing hyperpolarized (13)C magnetic resonance spectroscopic imaging was applied in orthotopic human glioblastoma xenografts for quantitative assessment of spatial variations in (13)C metabolic profiles and comparison with histopathology. A new compressed sensing sampling design with a factor of 3.72 acceleration was implemented to enable a factor of 4 increase in spatial resolution. Compressed sensing 3D (13)C magnetic resonance spectroscopic imaging data were acquired from a phantom and 10 tumor-bearing rats following injection of hyperpolarized [1-(13)C]-pyruvate using a 3T scanner. The (13)C metabolic profiles were compared with hematoxylin and eosin staining and carbonic anhydrase 9 staining. The high-resolution compressed sensing (13)C magnetic resonance spectroscopic imaging data enabled the differentiation of distinct (13)C metabolite patterns within abnormal tissues with high specificity in similar scan times compared to the fully sampled method. The results from pathology confirmed the different characteristics of (13)C metabolic profiles between viable, non-necrotic, nonhypoxic tumor, and necrotic, hypoxic tissue. Copyright © 2012 Wiley Periodicals, Inc.

  17. Simultaneous PET/MRI with (13)C magnetic resonance spectroscopic imaging (hyperPET): phantom-based evaluation of PET quantification.

    Science.gov (United States)

    Hansen, Adam E; Andersen, Flemming L; Henriksen, Sarah T; Vignaud, Alexandre; Ardenkjaer-Larsen, Jan H; Højgaard, Liselotte; Kjaer, Andreas; Klausen, Thomas L

    2016-12-01

    Integrated PET/MRI with hyperpolarized (13)C magnetic resonance spectroscopic imaging ((13)C-MRSI) offers simultaneous, dual-modality metabolic imaging. A prerequisite for the use of simultaneous imaging is the absence of interference between the two modalities. This has been documented for a clinical whole-body system using simultaneous (1)H-MRI and PET but never for (13)C-MRSI and PET. Here, the feasibility of simultaneous PET and (13)C-MRSI as well as hyperpolarized (13)C-MRSI in an integrated whole-body PET/MRI hybrid scanner is evaluated using phantom experiments. Combined PET and (13)C-MRSI phantoms including a NEMA [(18)F]-FDG phantom, (13)C-acetate and (13)C-urea sources, and hyperpolarized (13)C-pyruvate were imaged repeatedly with PET and/or (13)C-MRSI. Measurements evaluated for interference effects included PET activity values in the largest sphere and a background region; total number of PET trues; and (13)C-MRSI signal-to-noise ratio (SNR) for urea and acetate phantoms. Differences between measurement conditions were evaluated using t tests. PET and (13)C-MRSI data acquisition could be performed simultaneously without any discernible artifacts. The average difference in PET activity between acquisitions with and without simultaneous (13)C-MRSI was 0.83 (largest sphere) and -0.76 % (background). The average difference in net trues was -0.01 %. The average difference in (13)C-MRSI SNR between acquisitions with and without simultaneous PET ranged from -2.28 to 1.21 % for all phantoms and measurement conditions. No differences were significant. The system was capable of (13)C-MRSI of hyperpolarized (13)C-pyruvate. Simultaneous PET and (13)C-MRSI in an integrated whole-body PET/MRI hybrid scanner is feasible. Phantom experiments showed that possible interference effects introduced by acquiring data from the two modalities simultaneously are small and non-significant. Further experiments can now investigate the benefits of simultaneous PET and

  18. Evidence for Rapid Oxidative Phosphorylation and Lactate Fermentation in Motile Human Sperm by Hyperpolarized (13)C Magnetic Resonance Spectroscopy.

    Science.gov (United States)

    Reynolds, Steven; Ismail, Nurul Fadhlina Bt; Calvert, Sarah J; Pacey, Allan A; Paley, Martyn N J

    2017-06-28

    Poor sperm motility is a common cause of male infertility for which there are no empirical therapies. Sperm motility is powered by adenosine triphosphate but the relative importance of lactate fermentation and Oxidative Phosphorylation (OxPhos) is debated. To study the relationship between energy metabolism and sperm motility we used dissolution Dynamic Nuclear Polarization (dDNP) for the first time to show the rapid conversion of (13)C1-pyruvate to lactate and bicarbonate, indicating active glycolytic and OxPhos metabolism in sperm. The magnitude of both lactate and bicarbonate signals were positively correlated with the concentration of progressively motile sperm. After controlling for sperm concentration, increased progressive sperm motility generated more pyruvate conversion to lactate and bicarbonate. The technique of dDNP allows 'snapshots' of sperm metabolism to be tracked over the different stages of their life. This may provide help to uncover the causes of poor sperm motility and suggest new approaches for novel treatments or therapies.

  19. Dissolution Dynamic Nuclear Polarization of Non-Self-Glassing Agents: Spectroscopy and Relaxation of Hyperpolarized [1-13C]Acetate

    DEFF Research Database (Denmark)

    Flori, Alessandra; Liserani, Matteo; Bowen, Sean

    2015-01-01

    The intrinsic physicochemical properties of the sample formulation are the key factors for efficient hyperpolarization through dissolution dynamic nuclear polarization (dissolution-DNP). We provide a comprehensive characterization of the DNP process for Na-[1-13C]acetate selected as a model for non...

  20. High-resolution hyperpolarized in vivo metabolic 13C spectroscopy at low magnetic field (48.7 mT) following murine tail-vein injection

    Science.gov (United States)

    Coffey, Aaron M.; Feldman, Matthew A.; Shchepin, Roman V.; Barskiy, Danila A.; Truong, Milton L.; Pham, Wellington; Chekmenev, Eduard Y.

    2017-08-01

    High-resolution 13C NMR spectroscopy of hyperpolarized succinate-1-13C-2,3-d2 is reported in vitro and in vivo using a clinical-scale, biplanar (80 cm-gap) 48.7 mT permanent magnet with a high homogeneity magnetic field. Non-localized 13C NMR spectra were recorded at 0.52 MHz resonance frequency over the torso of a tumor-bearing mouse every 2 s. Hyperpolarized 13C NMR signals with linewidths of ∼3 Hz (corresponding to ∼6 ppm) were recorded in vitro (2 mL in a syringe) and in vivo (over a mouse torso). Comparison of the full width at half maximum (FWHM) for 13C NMR spectra acquired at 48.7 mT and at 4.7 T in a small-animal MRI scanner demonstrates a factor of ∼12 improvement for the 13C resonance linewidth attainable at 48.7 mT compared to that at 4.7 T in vitro. 13C hyperpolarized succinate-1-13C resonance linewidths in vivo are at least one order of magnitude narrower at 48.7 mT compared to those observed in high-field (≥3 T) studies employing HP contrast agents. The demonstrated high-resolution 13C in vivo spectroscopy could be useful for high-sensitivity spectroscopic studies involving monitoring HP agent uptake or detecting metabolism using HP contrast agents with sufficiently large 13C chemical shift differences.

  1. Storage of hydrogen spin polarization in long-lived 13C2 singlet order and implications for hyperpolarized magnetic resonance imaging.

    Science.gov (United States)

    Feng, Yesu; Theis, Thomas; Liang, Xiaofei; Wang, Qiu; Zhou, Pei; Warren, Warren S

    2013-07-03

    Hyperpolarized magnetic resonance imaging (MRI) is a powerful technique enabling real-time monitoring of metabolites at concentration levels not accessible by standard MRI techniques. A considerable challenge this technique faces is the T1 decay of the hyperpolarization upon injection into the system under study. Here we show that A(n)A'(n)XX' spin systems such as (13)C2-1,2-diphenylacetylene ((13)C2-DPA) sustain long-lived polarization for both (13)C and (1)H spins with decay constants of almost 4.5 min at high magnetic fields of up to 16.44 T without spin-locking; the T1 of proton polarization is only 3.8 s. Therefore, storage of the proton polarization in a (13)C2-singlet state causes a 69-fold extension of the spin lifetime. Notably, this extension is demonstrated with proton-only pulse sequences, which can be readily implemented on standard clinical scanners.

  2. Mesoporous Silica Nanoparticles Loaded with Surfactant: Low Temperature Magic Angle Spinning 13C and 29Si NMR Enhanced by Dynamic Nuclear Polarization

    Energy Technology Data Exchange (ETDEWEB)

    Lafon, Olivier [Universite de Lille Nord de France; Thankamony, Aany S. Lilly [Universite de Lille Nord de France; Kokayashi, Takeshi [Ames Laboratory; Carnevale, Diego [Ecole Polytechnique Federale de Lausanne; Vitzthum, Veronika [Ecole Polytechnique Federale de Lausanne; Slowing, Igor I. [Ames Laboratory; Kandel, Kapil [Ames Laboratory; Vezin, Herve [Universite de Lille Nord de France; Amoureux, Jean-Paul [Universite de Lille Nord de France; Bodenhausen, Geoffrey [Ecole Polytechnique Federale de Lausanne; Pruski, Marek [Ames Laboratory

    2012-12-21

    We show that dynamic nuclear polarization (DNP) can be used to enhance NMR signals of 13C and 29Si nuclei located in mesoporous organic/inorganic hybrid materials, at several hundreds of nanometers from stable radicals (TOTAPOL) trapped in the surrounding frozen disordered water. The approach is demonstrated using mesoporous silica nanoparticles (MSN), functionalized with 3-(N-phenylureido)propyl (PUP) groups, filled with the surfactant cetyltrimethylammonium bromide (CTAB). The DNP-enhanced proton magnetization is transported into the mesopores via 1H–1H spin diffusion and transferred to rare spins by cross-polarization, yielding signal enhancements εon/off of around 8. When the CTAB molecules are extracted, so that the radicals can enter the mesopores, the enhancements increase to εon/off ≈ 30 for both nuclei. A quantitative analysis of the signal enhancements in MSN with and without surfactant is based on a one-dimensional proton spin diffusion model. The effect of solvent deuteration is also investigated.

  3. AN INTERMOLECULAR 13C{1H} NUCLEAR OVERHAUSER EFFECT FOR THE CARBON OF CCl4 IN POLYMER SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    YAN Xin; WANG Dehua; QIAN Baogong

    1991-01-01

    An intermolecular 13C{1H} NOE of CCl4 in the solutions of polystyrene and polybutadiene and their copolymers was observed. The results show that the defined polymer-CCl4 interaction variable has a linear relation with the polymer composition and the difference of solubility parameters and exponentially depends on the reciprocal of temperature.

  4. A combination strategy for extraction and isolation of multi-component natural products by systematic two-phase solvent extraction-(13)C nuclear magnetic resonance pattern recognition and following conical counter-current chromatography separation: Podophyllotoxins and flavonoids from Dysosma versipellis (Hance) as examples.

    Science.gov (United States)

    Yang, Zhi; Wu, Youqian; Wu, Shihua

    2016-01-29

    Despite of substantial developments of extraction and separation techniques, isolation of natural products from natural resources is still a challenging task. In this work, an efficient strategy for extraction and isolation of multi-component natural products has been successfully developed by combination of systematic two-phase liquid-liquid extraction-(13)C NMR pattern recognition and following conical counter-current chromatography separation. A small-scale crude sample was first distributed into 9 systematic hexane-ethyl acetate-methanol-water (HEMWat) two-phase solvent systems for determination of the optimum extraction solvents and partition coefficients of the prominent components. Then, the optimized solvent systems were used in succession to enrich the hydrophilic and lipophilic components from the large-scale crude sample. At last, the enriched components samples were further purified by a new conical counter-current chromatography (CCC). Due to the use of (13)C NMR pattern recognition, the kinds and structures of major components in the solvent extracts could be predicted. Therefore, the method could collect simultaneously the partition coefficients and the structural information of components in the selected two-phase solvents. As an example, a cytotoxic extract of podophyllotoxins and flavonoids from Dysosma versipellis (Hance) was selected. After the systematic HEMWat system solvent extraction and (13)C NMR pattern recognition analyses, the crude extract of D. versipellis was first degreased by the upper phase of HEMWat system (9:1:9:1, v/v), and then distributed in the two phases of the system of HEMWat (2:8:2:8, v/v) to obtain the hydrophilic lower phase extract and lipophilic upper phase extract, respectively. These extracts were further separated by conical CCC with the HEMWat systems (1:9:1:9 and 4:6:4:6, v/v). As results, total 17 cytotoxic compounds were isolated and identified. In general, whole results suggested that the strategy was very

  5. Nuclear Magnetic Resonance Gyroscope

    Science.gov (United States)

    Larsen, Michael; Griffith, Robert; Bulatowicz, Michael

    2014-03-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation (NGC) has concluded the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This presentation will describe the operational principles, design basics, and demonstrated performance of the NMRG including an overview of the NGC designs developed and demonstrated in the DARPA gyro development program.

  6. Earth's magnetic field enabled scalar coupling relaxation of 13C nuclei bound to fast-relaxing quadrupolar 14N in amide groups.

    Science.gov (United States)

    Chiavazza, Enrico; Kubala, Eugen; Gringeri, Concetta V; Düwel, Stephan; Durst, Markus; Schulte, Rolf F; Menzel, Marion I

    2013-02-01

    Scalar coupling relaxation, which is usually only associated with closely resonant nuclei (e.g., (79)Br-(13)C), can be a very effective relaxation mechanism. While working on hyperpolarized [5-(13)C]glutamine, fast liquid-state polarization decay during transfer to the MRI scanner was observed. This behavior could hypothetically be explained by substantial T(1) shortening due to a scalar coupling contribution (type II) to the relaxation caused by the fast-relaxing quadrupolar (14)N adjacent to the (13)C nucleus in the amide group. This contribution is only effective in low magnetic fields (i.e., less than 800 μT) and prevents the use of molecules bearing the (13)C-amide group as hyperpolarized MRS/MRI probes. In the present work, this hypothesis is explored both theoretically and experimentally. The results show that high hyperpolarization levels can be retained using either a (15)N-labeled amide or by applying a magnetic field during transfer of the sample from the polarizer to the MRI scanner.

  7. Shell effects in nuclear magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Kondratyev, V.N.; Maruyama, Toshiki; Chiba, Satoshi [Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

    2000-08-01

    The magnetization of nuclei in strong magnetic fields associated with magnetars' is considered within the shell model. It is demonstrated that the magnetic field gives rise to a phase-shift of the shell-oscillations in nuclear masses shifting significantly the nuclear magic numbers of the iron region towards smaller mass numbers. Shell-effects are found to result in anomalies of the nuclear magnetization. Such anomalies resemble the behavior associated with a phase transition. (author)

  8. ({sup 1} H, {sup 13} C and {sup 31} P) NMR of phosphonic acid derivatives; Ressonancia magnetica nuclear ({sup 1} H, {sup 13} C, {sup 31} P) de derivados do acido fosfonico

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Valdevino; Costa, Valentim E. Uberti [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Quimica

    1991-12-31

    In the last years the development of phosphates analogues in the medical and agricultural pesticides has being very expressive. {sup 1} H, {sup 13} C and mainly {sup 31} P NMR are used for stereochemical and conformational analysis, and reactivity studies on the compounds resulting from those chemical processes 2 refs., 4 figs., 1 tab.

  9. Absence of hyperfine effects in 13C-graphene spin-valve devices

    NARCIS (Netherlands)

    Wojtaszek, M.; Vera-Marun, I.J.; Whiteway, E.; Hilke, M.; Wees, B.J. van

    2014-01-01

    The carbon isotope 13C, in contrast to 12C, possesses a nuclear magnetic moment and can induce electron spin dephasing in graphene. This effect is usually neglected due to the low abundance of 13C in natural carbon allotropes (~1%). Chemical vapor deposition (CVD) allows for artificial synthesis of

  10. Absence of hyperfine effects in 13C-graphene spin-valve devices

    NARCIS (Netherlands)

    Wojtaszek, M.; Vera-Marun, I.J.; Whiteway, E.; Hilke, M.; Wees, B.J. van

    2014-01-01

    The carbon isotope 13C, in contrast to 12C, possesses a nuclear magnetic moment and can induce electron spin dephasing in graphene. This effect is usually neglected due to the low abundance of 13C in natural carbon allotropes (~1%). Chemical vapor deposition (CVD) allows for artificial synthesis of

  11. Sensitive Magnetic Control of Ensemble Nuclear Spin Hyperpolarisation in Diamond

    CERN Document Server

    Wang, Hai-Jing; Avalos, Claudia E; Seltzer, Scott J; Budker, Dmitry; Pines, Alexander; Bajaj, Vikram S

    2012-01-01

    Dynamic nuclear polarisation, which transfers the spin polarisation of electrons to nuclei, is routinely applied to enhance the sensitivity of nuclear magnetic resonance; it is also critical in spintronics, particularly when spin hyperpolarisation can be produced and controlled optically or electrically. Here we show the complete polarisation of nuclei located near the optically-polarised nitrogen-vacancy (NV) centre in diamond. When approaching the ground-state level anti-crossing condition of the NV electron spins, 13C nuclei in the first-shell are polarised in a pattern that depends sensitively and sharply upon the magnetic field. Based on the anisotropy of the hyperfine coupling and of the optical polarisation mechanism, we predict and observe a complete reversal of the nuclear spin polarisation with a few-mT change in the magnetic field. The demonstrated sensitive magnetic control of nuclear polarisation at room temperature will be useful for sensitivity-enhanced NMR, nuclear-based spintronics, and quant...

  12. Heteronuclear 2D-correlations in a uniformly [13C, 15N] labeled membrane-protein complex at ultra-high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Egorova-Zachernyuk, T.A.; Hollander, J. [Gorlaeus Laboratories (Netherlands); Fraser, N. [University of Glasgow, Division of Biochemistry and Molecular Biology (United Kingdom); Gast, P.; Hoff, A.J. [Leiden University, Huygens Laboratories (Netherlands); Cogdell, R. [University of Glasgow, Division of Biochemistry and Molecular Biology (United Kingdom); Groot, H.J.M. de; Baldus, M. [Gorlaeus Laboratories (Netherlands)

    2001-03-15

    One- and two-dimensional solid-state NMR experiments on a uniformly labeled intrinsic membrane-protein complex at ultra-high magnetic fields are presented. Two-dimensional backbone and side-chain correlations for a [U-{sup 13}C,{sup 15}N] labeled version of the LH2 light-harvesting complex indicate significant resolution at low temperatures and under Magic Angle Spinning. Tentative assignments of some of the observed correlations are presented and attributed to the {alpha}-helical segments of the protein, mostly found in the membrane interior.

  13. Design and test of a double-nuclear RF coil for (1)H MRI and (13)C MRSI at 7T.

    Science.gov (United States)

    Rutledge, Omar; Kwak, Tiffany; Cao, Peng; Zhang, Xiaoliang

    2016-06-01

    RF coil operation at the ultrahigh field of 7T is fraught with technical challenges that limit the advancement of novel human in vivo applications at 7T. In this work, a hybrid technique combining a microstrip transmission line and a lumped-element L-C loop coil to form a double-nuclear RF coil for proton magnetic resonance imaging and carbon magnetic resonance spectroscopy at 7T was proposed and investigated. Network analysis revealed a high Q-factor and excellent decoupling between the coils. Proton images and localized carbon spectra were acquired with high sensitivity. The successful testing of this novel double-nuclear coil demonstrates the feasibility of this hybrid design for double-nuclear MR imaging and spectroscopy studies at the ultrahigh field of 7T.

  14. Analytical continuous slowing down model for nuclear reaction cross-section measurements by exploitation of stopping for projectile energy scanning and results for 13C(3He,α)12C and 13C(3He,p)15N

    Science.gov (United States)

    Möller, S.

    2017-03-01

    Ion beam analysis is a set of precise, calibration free and non-destructive methods for determining surface-near concentrations of potentially all elements and isotopes in a single measurement. For determination of concentrations the reaction cross-section of the projectile with the targets has to be known, in general at the primary beam energy and all energies below. To reduce the experimental effort of cross-section measurements a new method is presented here. The method is based on the projectile energy reduction when passing matter of thick targets. The continuous slowing down approximation is used to determine cross-sections from a thick target at projectile energies below the primary energy by backward calculation of the measured product spectra. Results for 12C(3He,p)14N below 4.5 MeV are in rough agreement with literature data and reproduce the measured spectra. New data for reactions of 3He with 13C are acquired using the new technique. The applied approximations and further applications are discussed.

  15. Chemical shift tensor determination using magnetically oriented microcrystal array (MOMA): 13C solid-state CP NMR without MAS

    Science.gov (United States)

    Kusumi, R.; Kimura, F.; Song, G.; Kimura, T.

    2012-10-01

    Chemical shift tensors for the carboxyl and methyl carbons of L-alanine crystals were determined using a magnetically oriented microcrystal array (MOMA) prepared from a microcrystalline powder sample of L-alanine. A MOMA is a single-crystal-like composite in which microcrystals are aligned three-dimensionally in a matrix resin. The single-crystal rotation method was applied to the MOMA to determine the principal values and axes of the chemical shift tensors. The result showed good agreement with the literature data for the single crystal of L-alanine. This demonstrates that the present technique is a powerful tool for determining the chemical shift tensor of a crystal from a microcrystal powder sample.

  16. NMR structure analysis of uniformly 13C-labeled carbohydrates.

    Science.gov (United States)

    Fontana, Carolina; Kovacs, Helena; Widmalm, Göran

    2014-06-01

    In this study, a set of nuclear magnetic resonance experiments, some of them commonly used in the study of (13)C-labeled proteins and/or nucleic acids, is applied for the structure determination of uniformly (13)C-enriched carbohydrates. Two model substances were employed: one compound of low molecular weight [(UL-(13)C)-sucrose, 342 Da] and one compound of medium molecular weight ((13)C-enriched O-antigenic polysaccharide isolated from Escherichia coli O142, ~10 kDa). The first step in this approach involves the assignment of the carbon resonances in each monosaccharide spin system using the anomeric carbon signal as the starting point. The (13)C resonances are traced using (13)C-(13)C correlations from homonuclear experiments, such as (H)CC-CT-COSY, (H)CC-NOESY, CC-CT-TOCSY and/or virtually decoupled (H)CC-TOCSY. Based on the assignment of the (13)C resonances, the (1)H chemical shifts are derived in a straightforward manner using one-bond (1)H-(13)C correlations from heteronuclear experiments (HC-CT-HSQC). In order to avoid the (1) J CC splitting of the (13)C resonances and to improve the resolution, either constant-time (CT) in the indirect dimension or virtual decoupling in the direct dimension were used. The monosaccharide sequence and linkage positions in oligosaccharides were determined using either (13)C or (1)H detected experiments, namely CC-CT-COSY, band-selective (H)CC-TOCSY, HC-CT-HSQC-NOESY or long-range HC-CT-HSQC. However, due to the short T2 relaxation time associated with larger polysaccharides, the sequential information in the O-antigen polysaccharide from E. coli O142 could only be elucidated using the (1)H-detected experiments. Exchanging protons of hydroxyl groups and N-acetyl amides in the (13)C-enriched polysaccharide were assigned by using HC-H2BC spectra. The assignment of the N-acetyl groups with (15)N at natural abundance was completed by using HN-SOFAST-HMQC, HNCA, HNCO and (13)C-detected (H)CACO spectra.

  17. Parahydrogen enhanced zero-field nuclear magnetic resonance

    CERN Document Server

    Theis, Thomas; Kervern, Gwendal; Knappe, Svenja; Kitching, John; Ledbetter, Micah; Budker, Dmitry; Pines, Alex

    2011-01-01

    Nuclear magnetic resonance (NMR), conventionally detected in multi-tesla magnetic fields, is a powerful analytical tool for the determination of molecular identity, structure, and function. With the advent of prepolarization methods and alternative detection schemes using atomic magnetometers or superconducting quantum interference devices (SQUIDs), NMR in very low- (~earth's field), and even zero-field, has recently attracted considerable attention. Despite the use of SQUIDs or atomic magnetometers, low-field NMR typically suffers from low sensitivity compared to conventional high-field NMR. Here we demonstrate direct detection of zero-field NMR signals generated via parahydrogen induced polarization (PHIP), enabling high-resolution NMR without the use of any magnets. The sensitivity is sufficient to observe spectra exhibiting 13C-1H J-couplings in compounds with 13C in natural abundance in a single transient. The resulting spectra display distinct features that have straightforward interpretation and can be...

  18. Local and bulk 13C hyperpolarization in NV-centered diamonds at variable fields and orientations

    CERN Document Server

    Alvarez, Gonzalo A; Fischer, Ran; London, Paz; Kanda, Hisao; Onoda, Shinobu; Isoya, Junichi; Gershoni, David; Frydman, Lucio

    2014-01-01

    Polarizing nuclear spins is of fundamental importance in biology, chemistry and physics. Methods for hyperpolarizing 13C nuclei from free electrons in bulk, usually demand operation at cryogenic temperatures. Room-temperature approaches targeting diamonds with nitrogen-vacancy (NV) centers could alleviate this need, but hitherto proposed strategies lack generality as they demand stringent conditions on the strength and/or alignment of the magnetic field. We report here an approach for achieving efficient electron->13C spin alignment transfers, compatible with a broad range of magnetic field strengths and field orientations with respect to the diamond crystal. This versatility results from combining coherent microwave- and incoherent laser-induced transitions between selected energy states of the coupled electron-nuclear spin manifold. 13C-detected Nuclear Magnetic Resonance (NMR) experiments demonstrate that this hyperpolarization can be transferred via first-shell or via distant 13Cs, throughout the nuclear ...

  19. Nuclear magnetic resonance studies of the regulation of the pentose phosphate pathway

    Energy Technology Data Exchange (ETDEWEB)

    Bolo, N.R.

    1991-11-01

    The goal of this work is to investigate the potential for and limitations of in vivo nuclear magnetic resonance (NMR) spectroscopy for quantitation of glucose flux through the pentose phosphate pathway (shunt). Interest in the shunt is motivated by the possibility that its activity may be greatly increased in cancer and in the pathological states of cardiac and cerebral ischemia. The ability to dynamically monitor flux through the pentose shunt can give new knowledge about metabolism in pathological states. {sup 13}C NMR spectroscopy was used to monitor shunt activity by determination of the ratios of ({sup 13}C-4) to ({sup 13}C-5)-glutamate, ({sup 13}C-3) to ({sup 13}C-2)-alanine or ({sup 13}C-3) to ({sup 13}C-2)-lactate produced when ({sup 13}C-2)-glucose is infused. These methods provide measures of the effect of oxidative stresses on shunt activity in systems ranging from cell free enzyme-substrate preparations to cell suspensions and whole animals. In anaerobic cell free preparations, the fraction of glucose flux through the shunt was monitored with a time resolution of 3 minutes. This work predicts the potential for in vivo human studies of pentose phosphate pathway activity based on the mathematical simulation of the {sup 13}C fractional enrichments of C4 and C5-glutamate as a function of shunt activity and on the signal-to- noise ratio acquired in {sup 13}C NMR human studies from the current literature.

  20. Starch biosynthesis and intermediary metabolism in maize kernels. Quantitative analysis of metabolite flux by nuclear magnetic resonance.

    Science.gov (United States)

    Glawischnig, Erich; Gierl, Alfons; Tomas, Adriana; Bacher, Adelbert; Eisenreich, Wolfgang

    2002-12-01

    The seeds of cereals represent an important sink for metabolites during the accumulation of storage products, and seeds are an essential component of human and animal nutrition. Understanding the metabolic interconversions (networks) underpinning storage product formation could provide the foundation for effective metabolic engineering of these primary nutritional sources. In this paper, we describe the use of retrobiosynthetic nuclear magnetic resonance analysis to establish the metabolic history of the glucose (Glc) units of starch in maize (Zea mays) kernels. Maize kernel cultures were grown with [U-(13)C(6)]Glc, [U-(13)C(12)]sucrose, or [1,2-(13)C(2)]acetate as supplements. After 19 d, starch was hydrolyzed, and the isotopomer composition of the resulting Glc was determined by quantitative nuclear magnetic resonance analysis. [1,2-(13)C(2)]Acetate was not incorporated into starch. [U-(13)C(6)]Glc or [U-(13)C(12)]sucrose gave similar labeling patterns of polysaccharide Glc units, which were dominated by [1,2,3-(13)C(3)]- and [4,5,6-(13)C(3)]-isotopomers, whereas the [U-(13)C(6)]-, [3,4,5,6-(13)C(4)]-, [1,2-(13)C(2)]-, [5,6-(13)C(2)], [3-(13)C(1)], and [4-(13)C(1)]-isotopomers were present at lower levels. These isotopomer compositions indicate that there is extensive recycling of Glc before its incorporation into starch, via the enzymes of glycolytic, glucogenic, and pentose phosphate pathways. The relatively high abundance of the [5,6-(13)C(2)]-isotopomer can be explained by the joint operation of glycolysis/glucogenesis and the pentose phosphate pathway.

  1. GHz nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Cross, T.A.; Drobny, G.; Trewhella, J.

    1994-12-01

    For the past dozen years, 500- and 600-MHz spectrometers have become available in many laboratories. The first 600-MHz NMR spectrometer (at Carnegie Mellon University) was commissioned more than 15 years ago and, until 1994, represented the highest field available for high-resolution NMR. This year, we have witnessed unprecedented progress in the development of very high field magnets for NMR spectroscopy, including the delivery of the first commercial 750-MHz NMR spectrometers. In addition, NMR signals have been obtained from 20-Tesla magnets (850 MHz for {sup 1}H`s) at both Los Alamos National Laboratory and Florida State University in the NHMFL (National High Magnetic Field Laboratory). These preliminary experiments have been performed in magnets with 100-ppm homogeneity, but a 20-Tesla magnet developed for the NHMFL will be brought to field this year with a projected homogeneity of 0.1 ppm over a 1-cm-diam spherical volume.

  2. Nuclear magnetic resonance of D(-)-{alpha}-amino-benzyl penicillin; Ressonancia magnetica nuclear da D(-)-{alpha}-amino-benzil penicilina

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Monica R.M.P.; Gemal, Andre L.; San Gil, Rosane A.S. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica; Menezes, Sonia M.C. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    1995-12-31

    The development of new drugs from penicillins has induced the study of this substances by nuclear magnetic resonance. Several samples of D(-)-{alpha}-amino-benzyl penicillin were analysed using {sup 13} C NMR techniques in aqueous solution and solid state. Spectral data of this compounds were shown and the results were presented and analysed 7 figs., 4 tabs.

  3. Evanescent Waves Nuclear Magnetic Resonance

    DEFF Research Database (Denmark)

    Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad

    2016-01-01

    Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order...

  4. Evanescent Waves Nuclear Magnetic Resonance

    DEFF Research Database (Denmark)

    Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad

    2016-01-01

    Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order to char...... a new road to a better understanding of the evanescent waves component in NMR with the opportunity to perform localized spectroscopy and imaging....

  5. In vivo proton observed carbon edited (POCE) (13) C magnetic resonance spectroscopy of the rat brain using a volumetric transmitter and receive-only surface coil on the proton channel.

    Science.gov (United States)

    Kumaragamage, Chathura; Madularu, Dan; Mathieu, Axel P; De Feyter, Henk; Rajah, M Natasha; Near, Jamie

    2017-05-12

    In vivo carbon-13 ((13) C) MR spectroscopy (MRS) is capable of measuring energy metabolism and neuroenergetics, noninvasively in the brain. Indirect ((1) H-[(13) C]) MRS provides sensitivity benefits compared with direct (13) C methods, and normally includes a (1) H surface coil for both localization and signal reception. The aim was to develop a coil platform with homogenous B1+ and use short conventional pulses for short echo time proton observed carbon edited (POCE) MRS. A (1) H-[(13) C] MRS coil platform was designed with a volumetric resonator for (1) H transmit, and surface coils for (1) H reception and (13) C transmission. The Rx-only (1) H surface coil nullifies the requirement for a T/R switch before the (1) H preamplifier; the highpass filter and preamplifier can be placed proximal to the coil, thus minimizing sensitivity losses inherent with POCE-MRS systems described in the literature. The coil platform was evaluated with a PRESS-POCE sequence (TE = 12.6 ms) on a rat model. The coil provided excellent localization, uniform spin nutation, and sensitivity. (13) C labeling of Glu-H4 and Glx-H3 peaks, and the Glx-H2 peaks were observed approximately 13 and 21 min following the infusion of 1-(13) C glucose, respectively. A convenient and sensitive platform to study energy metabolism and neurotransmitter cycling is presented. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  6. Electric dipole moment of 13C

    Science.gov (United States)

    Yamanaka, Nodoka; Yamada, Taiichi; Hiyama, Emiko; Funaki, Yasuro

    2017-06-01

    We calculate for the first time the electric dipole moment (EDM) of 13C generated by the isovector charge conjugation-parity (CP)-odd pion exchange nuclear force in the α -cluster model, which describes well the structures of low-lying states of the 13C nucleus. The linear dependence of the EDM of 13C on the neutron EDM and the isovector CP-odd nuclear coupling is found to be d13C=-0.33 dn-0.0020 G¯π(1 ) . The linear enhancement factor of the CP-odd nuclear coupling is smaller than that of the deuteron, due to the difference of the structure between the 1 /21- state and the opposite-parity (1 /2+ ) states. We clarify the role of the structure played in the enhancement of the EDM. This result provides good guiding principles to search for other nuclei with large enhancement factor. We also mention the role of the EDM of 13C in determining the new physics beyond the standard model.

  7. 13C MRS of Human Brain at 7 Tesla Using [2-13C]Glucose Infusion and Low Power Broadband Stochastic Proton Decoupling

    Science.gov (United States)

    Li, Shizhe; An, Li; Yu, Shao; Araneta, Maria Ferraris; Johnson, Christopher S.; Wang, Shumin; Shen, Jun

    2015-01-01

    Purpose 13C magnetic resonance spectroscopy (MRS) of human brain at 7 Tesla (T) may pose patient safety issues due to high RF power deposition for proton decoupling. The purpose of present work is to study the feasibility of in vivo 13C MRS of human brain at 7 T using broadband low RF power proton decoupling. Methods Carboxylic/amide 13C MRS of human brain by broadband stochastic proton decoupling was demonstrated on a 7 T scanner. RF safety was evaluated using the finite-difference time-domain method. 13C signal enhancement by nuclear Overhauser effect (NOE) and proton decoupling was evaluated in both phantoms and in vivo. Results At 7 T, the peak amplitude of carboxylic/amide 13C signals was increased by a factor of greater than 4 due to the combined effects of NOE and proton decoupling. The 7 T 13C MRS technique used decoupling power and average transmit power of less than 35 W and 3.6 W, respectively. Conclusion In vivo 13C MRS studies of human brain can be performed at 7 T well below the RF safety threshold by detecting carboxylic/amide carbons with broadband stochastic proton decoupling. PMID:25917936

  8. Nuclear magnetic ordering in silver

    Energy Technology Data Exchange (ETDEWEB)

    Lefmann, K.

    1995-12-01

    Nuclear antiferromagnetic ordering has been observed by neutron diffraction in a single crystal of {sup 109}Ag. The critical temperature is found to 700 pK, and the critical field is 100 {mu}T. From the paramagnetic phase a second order phase transition leads into a type-I 1-k structure with long range order. The experiments have taken place at the Hahn-Meitner Institut in Berlin in collaboration with the low Temperature Laboratory in Helsinki, the Niels Bohr Institute in Copenhagen, and Risoe National Laboratory, Roskilde. The present report is a Ph.D. thesis which has been successfully defended at the Niels Bohr Institute. Besides the results of the nuclear ordering experiments the thesis contains a description of the theoretical background for nuclear magnetism and a review of earlier nuclear ordering experiments as well as theoretical work. The principles for studying polarized nuclei with use of polarized and unpolarized neutrons are presented, as well as the results of such experiments. (au) 11 tabs., 59 ills., 143 refs.

  9. Investigating tumor perfusion by hyperpolarized (13) C MRI with comparison to conventional gadolinium contrast-enhanced MRI and pathology in orthotopic human GBM xenografts

    DEFF Research Database (Denmark)

    Park, Ilwoo; von Morze, Cornelius; Lupo, Janine M

    2016-01-01

    Dissolution dynamic nuclear polarization (DNP) enables the acquisition of (13) C magnetic resonance data with a high sensitivity. Recently, metabolically inactive hyperpolarized (13) C-labeled compounds have shown to be potentially useful for perfusion imaging. The purpose of this study was to va...

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

    DEFF Research Database (Denmark)

    Larsen, Flemming H; Byg, Inge; Damager, Iben

    2011-01-01

    Hydration of rhamnogalacturonan-I (RG-I) derived from potato cell wall was analyzed by 13C single-pulse (SP) magic-angle-spinning (MAS) and 13C cross-polarization (CP) MAS nuclear magnetic resonance (NMR) and supported by 2H SP/MAS NMR experiments. The study shows that the arabinan side chains...

  11. The electric dipole moment of $^{13}$C

    CERN Document Server

    Yamanaka, Nodoka; Hiyama, Emiko; Funaki, Yasuro

    2016-01-01

    We calculate for the first time the electric dipole moment (EDM) of $^{13}$C generated by the isovector CP-odd pion exchange nuclear force in the $\\alpha$-cluster model, which describes well the structures of low lying states of the $^{13}$C nucleus. The linear dependence of the EDM of $^{13}$C on the neutron EDM and the isovector CP-odd nuclear coupling is found to be $d_{^{13}{\\rm C}} = -0.33 d_n - 0.0012 \\bar G_\\pi^{(1)}$. The linear enhancement factor of the CP-odd nuclear coupling is smaller than that of the deuteron, due to the difference of the structure between the $1/2^-_1$ state and the opposite parity ($1/2^+$) states. We clarify the role of the structure played in the enhancement of the EDM. This result provides good guiding principles to search for other nuclei with large enhancement factor. We also mention the role of the EDM of $^{13}$C in determining the new physics beyond the standard model.

  12. Monitoring tumor response of prostate cancer to radiation therapy by multi-parametric 1H and hyperpolarized 13C magnetic resonance imaging

    Science.gov (United States)

    Zhang, Vickie Yi

    Radiation therapy is one of the most common curative therapies for patients with localized prostate cancer, but despite excellent success rates, a significant number of patients suffer post- treatment cancer recurrence. The accurate characterization of early tumor response remains a major challenge for the clinical management of these patients. Multi-parametric MRI/1H MR spectroscopy imaging (MRSI) has been shown to increase the diagnostic performance in evaluating the effectiveness of radiation therapy. 1H MRSI can detect altered metabolic profiles in cancerous tissue. In this project, the concentrations of prostate metabolites from snap-frozen biopsies of recurrent cancer after failed radiation therapy were correlated with histopathological findings to identify quantitative biomarkers that predict for residual aggressive versus indolent cancer. The total choline to creatine ratio was significantly higher in recurrent aggressive versus indolent cancer, suggesting that use of a higher threshold tCho/Cr ratio in future in vivo 1H MRSI studies could improve the selection and therapeutic planning for patients after failed radiation therapy. Varying radiation doses may cause a diverse effect on prostate cancer micro-environment and metabolism, which could hold the key to improving treatment protocols for individual patients. The recent development and clinical translation of hyperpolarized 13C MRI have provided the ability to monitor both changes in the tumor micro-environment and its metabolism using a multi-probe approach, [1-13C]pyruvate and 13C urea, combined with 1H Multi-parametric MRI. In this thesis, hyperpolarized 13C MRI, 1H dynamic contrast enhancement, and diffusion weighted imaging were used to identify early radiation dose response in a transgenic prostate cancer model. Hyperpolarized pyruvate to lactate metabolism significantly decreased in a dose dependent fashion by 1 day after radiation therapy, prior to any changes observed using 1H DCE and diffusion

  13. Protein dynamics from nuclear magnetic relaxation.

    Science.gov (United States)

    Charlier, Cyril; Cousin, Samuel F; Ferrage, Fabien

    2016-05-01

    Nuclear magnetic resonance is a ubiquitous spectroscopic tool to explore molecules with atomic resolution. Nuclear magnetic relaxation is intimately connected to molecular motions. Many methods and models have been developed to measure and interpret the characteristic rates of nuclear magnetic relaxation in proteins. These approaches shed light on a rich and diverse range of motions covering timescales from picoseconds to seconds. Here, we introduce some of the basic concepts upon which these approaches are built and provide a series of illustrations.

  14. Analysis of the Electronic Structure of the Special Pair of a Bacterial Photosynthetic Reaction Center by (13) C Photochemically Induced Dynamic Nuclear Polarization Magic-Angle Spinning NMR Using a Double-Quantum Axis.

    Science.gov (United States)

    Najdanova, Marija; Gräsing, Daniel; Alia, A; Matysik, Jörg

    2017-07-26

    The origin of the functional symmetry break in bacterial photosynthesis challenges since several decades. Although structurally very similar, the two branches of cofactors in the reaction center (RC) protein complex act very differently. Upon photochemical excitation, an electron is transported along one branch, while the other remains inactive. Photochemically induced dynamic nuclear polarization (photo-CIDNP) magic-angle spinning (MAS) (13) C NMR revealed that the two bacteriochlorophyll cofactors forming the "Special Pair" donor dimer are already well distinguished in the electronic ground state. These previous studies are relying solely on (13) C-(13) C correlation experiments as radio-frequency-driven recoupling (RFDR) and dipolar-assisted rotational resonance (DARR). Obviously, the chemical-shift assignment is difficult in a dimer of tetrapyrrole macrocycles, having eight pyrrole rings of similar chemical shifts. To overcome this problem, an INADEQUATE type of experiment using a POST C7 symmetry-based approach is applied to selectively isotope-labeled bacterial RC of Rhodobacter (R.) sphaeroides wild type (WT). We, therefore, were able to distinguish unresolved sites of the macromolecular dimer. The obtained chemical-shift pattern is in-line with a concentric assembly of negative charge within the common center of the Special Pair supermolecule in the electronic ground state. © 2017 The American Society of Photobiology.

  15. Insights into the metabolic response to traumatic brain injury as revealed by 13C NMR spectroscopy.

    Directory of Open Access Journals (Sweden)

    Brenda eBartnik-Olson

    2013-10-01

    Full Text Available The present review highlights critical issues related to cerebral metabolism following traumatic brain injury (TBI and the use of 13C labeled substrates and nuclear magnetic resonance (NMR spectroscopy to study these changes. First we address some pathophysiologic factors contributing to metabolic dysfunction following TBI. We then examine how 13C NMR spectroscopy strategies have been used to investigate energy metabolism, neurotransmission, the intracellular redox state, and neuroglial compartmentation following injury. 13C NMR spectroscopy studies of brain extracts from animal models of TBI have revealed enhanced glycolytic production of lactate, evidence of pentose phosphate pathway (PPP activation, and alterations in neuronal and astrocyte oxidative metabolism that are dependent on injury severity. Differential incorporation of label into glutamate and glutamine from 13C labeled glucose or acetate also suggest TBI-induced adaptations to the glutamate-glutamine cycle.

  16. An Overview of Methods using 13C for Improved Compound Identification in Metabolomics and Natural Products

    Directory of Open Access Journals (Sweden)

    Chaevien S Clendinen

    2015-08-01

    Full Text Available Compound identification is a major bottleneck in metabolomics studies. In nuclear magnetic resonance (NMR investigations, resonance overlap often hinders unambiguous database matching or de novo compound identification. In liquid chromatography-mass spectrometry (LC-MS, discriminating between biological signals and background artifacts and reliable determination of molecular formulae are not always straightforward. We have designed and implemented several NMR and LC-MS approaches that utilize 13C, either enriched or at natural abundance, in metabolomics applications. For LC-MS applications, we describe a technique called isotopic ratio outlier analysis (IROA, which utilizes samples that are isotopically labeled with 5% (test and 95% (control 13C. This labeling strategy leads to characteristic isotopic patterns that allow the differentiation of biological signals from artifacts and yield the exact number of carbons, significantly reducing possible molecular formulae. The relative abundance between the test and control samples for every IROA feature can be determined simply by integrating the peaks that arise from the 5% and 95% channels. For NMR applications, we describe two 13C-based approaches. For samples at natural abundance, we have developed a workflow to obtain 13C-13C and 13C-1H statistical correlations using 1D 13C and 1H NMR spectra. For samples that can be isotopically labeled, we describe another NMR approach to obtain direct 13C-13C spectroscopic correlations. These methods both provide extensive information about the carbon framework of compounds in the mixture for either database matching or de novo compound identification. We also discuss strategies in which 13C NMR can be used to identify unknown compounds from IROA experiments. By combining technologies with the same samples, we can identify important biomarkers and corresponding metabolites of interest.

  17. Selective carbon 13 enrichment of side chain carbons of ginkgo lignin traced by carbon 13 nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Y. (Nagoya Univ. (Japan). Faculty of Agriculture); Robert, D.R. (CEA Centre d' Etudes de Grenoble, 38 (France). Dept. de Recherche Fondamentale sur la Matiere Condensee); Terashima, N. (Forest Products Lab., Madison, WI (United States))

    Although carbon 13 nuclear magnetic resonance spectroscopy ([sup 13]C-NMR) is widely used in lignin structural studies, serious difficulties are encountered in the assignments of [sup 13]C signals because of their extensive overlaps resulting from the complex structure of lignin and of delicate detection of minor structures. To overcome these difficulties, specifically [sup 13]C-enriched precursors of lignin biosynthesis, coniferin-[side chain-[beta]-[sup 13]C] and coniferin-[side chain-[gamma]-[sup 13]C], were administered to growing stems of ginkgo (Ginkgo biloba). The NMR analysis of the milled wood lignins isolated from the newly formed xylem showed that selective enrichment of specific carbons of protolignin in the cell wall was achieved without seriously disturbing the lignin biosynthesis. The presence of saturated methylene side chains in the protolignin was shown for the first time by this selective enrichment technique in combination with NMR analysis. (authors). 23 refs., 3 figs., 1 tab.

  18. Combining Nuclear Magnetic Resonance Spectroscopy and Density Functional Theory Calculations to Characterize Carvedilol Polymorphs.

    Science.gov (United States)

    Rezende, Carlos A; San Gil, Rosane A S; Borré, Leandro B; Pires, José Ricardo; Vaiss, Viviane S; Resende, Jackson A L C; Leitão, Alexandre A; De Alencastro, Ricardo B; Leal, Katia Z

    2016-09-01

    The experiments of carvedilol form II, form III, and hydrate by (13)C and (15)N cross-polarization magic-angle spinning (CP MAS) are reported. The GIPAW (gauge-including projector-augmented wave) method from DFT (density functional theory) calculations was used to simulate (13)C and (15)N chemical shifts. A very good agreement was found for the comparison between the global results of experimental and calculated nuclear magnetic resonance (NMR) chemical shifts for carvedilol polymorphs. This work aims a comprehensive understanding of carvedilol crystalline forms employing solution and solid-state NMR as well as DFT calculations.

  19. Mass spectrometry and /sup 13/C nuclear magnetic resonance spectroscopy of compounds modeling the glycopeptide linkage of glycoproteins

    Energy Technology Data Exchange (ETDEWEB)

    Blumberg, K.; Bush, C.A.

    1982-01-15

    The properties of several compounds useful as models for three-dimensional conformational studies and the investigation of the chemical degradation of glycopeptide linkages both of the N- and O-glycosidic type are described. Using the method of differential chemical shift in H/sub 2/O and D/sub 2/O as solvents, the carbon NMR spectrum of N-acetylglucosaminylasparagine, 1-N-acetyl-..beta..-D-glucopyranosylamine, and 1-N-acetyl-2-acetamido-..beta..-D-glycopyranosylamine has been assigned. Electron impact mass spectra of the peracetylated derivatives of the latter two compounds show a peak apparently unique to glycopyranosylamides at m/e = 269, no analog of which is observed in the mass spectra of other peracetylated sugars. As models of the ..cap alpha..-O-glycosidic linkage, fully assigned carbon NMR spectra of ..cap alpha..-methyl-N-acetylgalactosamine (GalNAc), ..cap alpha..-methyl-3-O-methyl GalNAc, and -GlcNAc as well as the disaccharide Glc-..beta..-l ..-->.. 3 GalNAc are reported. Because certain anomalies in the chemical shifts and /sup 1/J/sub CH/ observed in the disaccharide and in O-glycosylated glycoproteins are not observed in the simple model compounds, they may result from conformational interactions in the glycopeptides.

  20. NMR study of the 1-{sup 13}C glucose colon bacterial metabolism; Etude du metabolisme bacterien colique du 1-{sup 13}C glucose par RMN

    Energy Technology Data Exchange (ETDEWEB)

    Briet, F.; Flourie, B.; Pochart, P.; Rambaud, J.C.; Desjeux, J.F. [Hopital Saint-Lazare, 75 - Paris (France); Dallery, L. [Conservatoire National des Arts et Metiers (CNAM), 75 - Paris (France); Grivet, J.P. [Centre National de la Recherche Scientifique (CNRS), 45 - Orleans-la-Source (France)

    1994-12-31

    The aim of the study is to examine in-vitro and by nuclear magnetic resonance the biological pathways for the fermentation of the 1-{sup 13}C labelled glucose (99 atoms percent) by human colon bacteria. The preparation of the bacterial suspension and the glucose degradation kinetics are presented; the NMR analysis sensitivity and quantification features are discussed and results are presented. 2 figs., 1 ref.

  1. Metabolic pathways for ketone body production. /sup 13/C NMR spectroscopy of rat liver in vivo using /sup 13/C-multilabeled fatty acids

    Energy Technology Data Exchange (ETDEWEB)

    Pahl-Wostl, C.; Seelig, J.

    1986-11-04

    The hormonal regulation of ketogenesis in the liver of living rat has been studied noninvasively with /sup 13/C nuclear magnetic resonance. The spatial selection for the liver was better than 90%, with extrahepatic adipose tissue contribution only a very small amount of signal. The metabolic activities of the liver were investigated by infusion of /sup 13/C-labeled butyrate in the jugular vein of the anesthetized rat. The rate of butyrate infusion was chosen to be close to the maximum oxidative capacity of the rat liver, and the /sup 13/C signal intensities were enhanced by using doubly labeled (1,3-/sup 13/C)butyrate as a substrate. Different /sup 13/C NMR spectra and hence different metabolites were observed depending on the hormonal state of the animal. The /sup 13/C NMR studies demonstrate that even when rate of acetyl-CoA production are high, the disposal of this compound is not identical in fasted and diabetic animals. This supports previous suggestions that the redox state of the mitochondrion represents the most important factor in regulation. For a given metabolic state of the animal, different signal intensities were obtained depending on whether butyrate was labeled at C-1, C-3, or C-1,3. From the ratios of incorporation of /sup 13/C label into the carbons of 3-hydroxybutyrate, it could be estimated that a large fraction of butyrate evaded ..beta..-oxidation to acetyl-CoA but was converted directly to acetoacetyl-CoA. /sup 13/C-labeled glucose could be detected in vivo in the liver of diabetic rats.

  2. Measurement of untruncated nuclear spin interactions via zero- to ultralow-field nuclear magnetic resonance

    Science.gov (United States)

    Blanchard, J. W.; Sjolander, T. F.; King, J. P.; Ledbetter, M. P.; Levine, E. H.; Bajaj, V. S.; Budker, D.; Pines, A.

    2015-12-01

    Zero- to ultralow-field nuclear magnetic resonance (ZULF NMR) provides a new regime for the measurement of nuclear spin-spin interactions free from the effects of large magnetic fields, such as truncation of terms that do not commute with the Zeeman Hamiltonian. One such interaction, the magnetic dipole-dipole coupling, is a valuable source of spatial information in NMR, though many terms are unobservable in high-field NMR, and the coupling averages to zero under isotropic molecular tumbling. Under partial alignment, this information is retained in the form of so-called residual dipolar couplings. We report zero- to ultralow-field NMR measurements of residual dipolar couplings in acetonitrile-2-13C aligned in stretched polyvinyl acetate gels. This permits the investigation of dipolar couplings as a perturbation on the indirect spin-spin J coupling in the absence of an applied magnetic field. As a consequence of working at zero magnetic field, we observe terms of the dipole-dipole coupling Hamiltonian that are invisible in conventional high-field NMR. This technique expands the capabilities of zero- to ultralow-field NMR and has potential applications in precision measurement of subtle physical interactions, chemical analysis, and characterization of local mesoscale structure in materials.

  3. Simultaneous hyperpolarized (13)C-pyruvate MRI and (18)F-FDG-PET in cancer (hyperPET)

    DEFF Research Database (Denmark)

    Gutte Borgwardt, Henrik; Hansen, Adam E; Henriksen, Sarah T

    2015-01-01

    (DNP) and use of (13)C-pyruvate it is now possible to directly study the Warburg Effect through the rate of conversion of (13)C-pyruvate to (13)C-lactate. In this study, we combined it with (18)F-FDG-PET that studies uptake of glucose in the cells. A canine cancer patient with a histology verified......In this paper we demonstrate, for the first time, the feasibility of a new imaging concept - combined hyperpolarized (13)C-pyruvate magnetic resonance spectroscopic imaging (MRSI) and (18)F-FDG-PET imaging. This procedure was performed in a clinical PET/MRI scanner with a canine cancer patient. We...... have named this concept hyper PET. Intravenous injection of the hyperpolarized (13)C-pyruvate results in an increase of (13)C-lactate, (13)C-alanine and (13)C-CO2 ((13)C-HCO3) resonance peaks relative to the tissue, disease and the metabolic state probed. Accordingly, with dynamic nuclear polarization...

  4. Nuclear magnetic resonance. Tomography of tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Ethier, R.; Melanson, D.; Peters, T.M. (Montreal Neurological Inst., Quebec (Canada))

    1983-10-01

    Ten years following computerized tomography, a new technique called nuclear magnetic resonance revolutionizes the field of diagnostic imaging. A major advantage of nuclear magnetic resonance is that the danger of radiation is non-existent as compared to computerized tomography. When parts of the human body are subject to radio-frequencies while in a fixed magnetic field, its most detailed structures are revealed. The quality of images, the applications, as well as the indications are forever increasing. Images obtained at the level of the brain and spinal cord through nuclear magnetic resonance supercede those obtained through computerized tomography. Hence, it is most likely that myelography, along with pneumoencephalography will be eliminated as a diagnostic means. It is without a doubt that nuclear magnetic resonance is tomorrow's computerized tomography.

  5. Nuclear magnetic resonance spectral analysis and molecular properties of berberine

    Science.gov (United States)

    Huang, Ming-Ju; Lee, Ken S.; Hurley, Sharon J.

    An extensive theoretical study of berberine has been performed at the ab initio HF/6-31G**, HF/6-311G**, and B3LYP/6-311G** levels with and without solvent effects. The optimized structures are compared with X-ray data. We found that the optimized structures with solvent effects are in slightly better agreement with X-ray data than those without solvent effects. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of berberine were calculated by using the gauge-independent atomic orbital (GIAO) (with and without solvent effects), CSGT, and IGAIM methods. The calculated chemical shifts were compared with the two-dimensional NMR experimental data. Overall, the calculated chemical shifts show very good agreement with the experimental results. The harmonic vibrational frequencies for berberine were calculated at the B3LYP/6-311G** level.

  6. Simultaneous hyperpolarized 13C-pyruvate MRI and 18F-FDG-PET in cancer (hyperPET)

    DEFF Research Database (Denmark)

    Gutte, Henrik; Hansen, Adam E.; Henriksen, Sarah T.

    2015-01-01

    of 13C-pyruvate it is now possible to directly study the Warburg Effect through the rate of conversion of 13C-pyruvate to 13C-lactate. In this study, we combined it with 18F-FDG-PET that studies uptake of glucose in the cells. A canine cancer patient with a histology verified local recurrence......In this paper we demonstrate, for the first time, the feasibility of a new imaging concept - combined hyperpolarized 13C-pyruvate magnetic resonance spectroscopic imaging (MRSI) and 18F-FDG-PET imaging. This procedure was performed in a clinical PET/MRI scanner with a canine cancer patient. We have...... named this concept hyper PET. Intravenous injection of the hyperpolarized 13C-pyruvate results in an increase of 13C-lactate, 13C-alanine and 13CCO2 (13C-HCO3) resonance peaks relative to the tissue, disease and the metabolic state probed. Accordingly, with dynamic nuclear polarization (DNP) and use...

  7. Solid state {sup 13}C NMR analysis of Brazilian cretaceous ambers

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Ricardo; Azevedo, Debora A., E-mail: ricardopereira@iq.ufrj.b, E-mail: debora@iq.ufrj.b [Universidade Federal do Rio de Janeiro (IQ/UFRJ), Rio de Janeiro, RJ (Brazil). Inst. de Quimica. Lab. de Geoquimica Organica Molecular e Ambiental; San Gil, Rosane A.S. [Universidade Federal do Rio de Janeiro (IQ/UFRJ), RJ (Brazil). Inst. de Quimica. Lab. de RMN de Solidos; Carvalho, Ismar S. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Geociencias. Dept. de Geologia; Fernandes, Antonio Carlos S. [Museu Nacional (MN/UFRJ), RJ (Brazil). Dept. de Geologia e Paleontologia

    2011-07-01

    {sup 13}C cross polarization with magic angle spinning nuclear magnetic resonance ({sup 13}C CPMAS NMR) spectra have been obtained for the first time to three Cretaceous amber samples from South America. The samples were dated to Lower Cretaceous and collected in sediments from the Amazonas, Araripe and Reconcavo basins, Brazil. All samples have very similar spectra, consistent with a common paleobotanical source. Some aspects of the spectra suggest a relationship between Brazilian ambers and Araucariaceae family, such as intense resonances at 38-39 ppm. All samples are constituted by polylabdane structure associated to Class Ib resins, constituted by polymers of labdanoid diterpenes. Finally, information concerning some structural changes during maturation, such as isomerization of {Delta}{sup 8(17)} and {Delta}{sup 12(13)} unsaturations, were obtained by {sup 13}C NMR analyses. The results concerning botanical affinities are in accordance with previous results obtained by gas chromatography-mass spectrometry (GC-MS). (author)

  8. Nuclear spin conversion of water inside fullerene cages detected by low-temperature nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Mamone, Salvatore, E-mail: s.mamone@soton.ac.uk; Concistrè, Maria; Carignani, Elisa; Meier, Benno; Krachmalnicoff, Andrea; Johannessen, Ole G.; Denning, Mark; Carravetta, Marina; Whitby, Richard J.; Levitt, Malcolm H., E-mail: mhl@soton.ac.uk [School of Chemistry, University of Southampton, Southampton SO17 1BJ (United Kingdom); Lei, Xuegong; Li, Yongjun [Department of Chemistry, Columbia University, New York, New York 10027 (United States); Goh, Kelvin; Horsewill, Anthony J. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom)

    2014-05-21

    The water-endofullerene H{sub 2}O@C{sub 60} provides a unique chemical system in which freely rotating water molecules are confined inside homogeneous and symmetrical carbon cages. The spin conversion between the ortho and para species of the endohedral H{sub 2}O was studied in the solid phase by low-temperature nuclear magnetic resonance. The experimental data are consistent with a second-order kinetics, indicating a bimolecular spin conversion process. Numerical simulations suggest the simultaneous presence of a spin diffusion process allowing neighbouring ortho and para molecules to exchange their angular momenta. Cross-polarization experiments found no evidence that the spin conversion of the endohedral H{sub 2}O molecules is catalysed by {sup 13}C nuclei present in the cages.

  9. Using solid 13C NMR coupled with solution 31P NMR spectroscopy to investigate molecular species and lability of organic carbon and phosphorus from aquatic plants in Tai Lake, China

    Science.gov (United States)

    Aquatic plants are involved in the storage and release capacity for organic matter and nutrients. In this study, solid 13C and solution 31P nuclear magnetic resonance (NMR) spectroscopy were used to characterize the biomass samples of six aquatic plants. Solid 13C NMR spectroscopy revealed the domin...

  10. Impact of radiolysis and radiolytic corrosion on the release of {sup 13}C and {sup 37}Cl implanted into nuclear graphite: Consequences for the behaviour of {sup 14}C and {sup 36}Cl in gas cooled graphite moderated reactors

    Energy Technology Data Exchange (ETDEWEB)

    Moncoffre, N., E-mail: nathalie.moncoffre@ipnl.in2p3.fr [Université de Lyon, Université Lyon 1, CNRS/IN2P3, UMR5822, Institut de Physique Nucléaire de Lyon (IPNL) (France); Toulhoat, N. [Université de Lyon, Université Lyon 1, CNRS/IN2P3, UMR5822, Institut de Physique Nucléaire de Lyon (IPNL) (France); CEA/DEN, Centre de Saclay (France); Bérerd, N.; Pipon, Y. [Université de Lyon, Université Lyon 1, CNRS/IN2P3, UMR5822, Institut de Physique Nucléaire de Lyon (IPNL) (France); Université de Lyon, Université Lyon, IUT Lyon-1 département chimie (France); Silbermann, G. [Université de Lyon, Université Lyon 1, CNRS/IN2P3, UMR5822, Institut de Physique Nucléaire de Lyon (IPNL) (France); EDF – DPI - DIN – CIDEN, DIE - Division Environnement, Lyon (France); Blondel, A. [Université de Lyon, Université Lyon 1, CNRS/IN2P3, UMR5822, Institut de Physique Nucléaire de Lyon (IPNL) (France); Andra, Châtenay-Malabry (France); Galy, N. [Université de Lyon, Université Lyon 1, CNRS/IN2P3, UMR5822, Institut de Physique Nucléaire de Lyon (IPNL) (France); EDF – DPI - DIN – CIDEN, DIE - Division Environnement, Lyon (France); and others

    2016-04-15

    Graphite finds widespread use in many areas of nuclear technology based on its excellent moderator and reflector qualities as well as its strength and high temperature stability. Thus, it has been used as moderator or reflector in CO{sub 2} cooled nuclear reactors such as UNGG, MAGNOX, and AGR. However, neutron irradiation of graphite results in the production of {sup 14}C (dose determining radionuclide) and {sup 36}Cl (long lived radionuclide), these radionuclides being a key issue regarding the management of the irradiated waste. Whatever the management option (purification, storage, and geological disposal), a previous assessment of the radioactive inventory and the radionuclide's location and speciation has to be made. During reactor operation, the effects of radiolysis are likely to promote the radionuclide release especially at the gas/graphite interface. Radiolysis of the coolant is mainly initiated through γ irradiation as well as through Compton electrons in the graphite pores. Radiolysis can be simulated in laboratory using γ irradiation or ion irradiation. In this paper, {sup 13}C, {sup 37}Cl and {sup 14}N are implanted into virgin nuclear graphite in order to simulate respectively the presence of {sup 14}C, {sup 36}Cl and nitrogen, a {sup 14}C precursor. Different irradiation experiments were carried out using different irradiation devices on implanted graphite brought into contact with a gas simulating the coolant. The aim was to assess the effects of gas radiolysis and radiolytic corrosion induced by γ or He{sup 2+} irradiation at the gas/graphite interface in order to evaluate their role on the radionuclide release. Our results allow inferring that radiolytic corrosion has clearly promoted the release of {sup 14}C, {sup 36}Cl and {sup 14}N located at the graphite brick/gas interfaces and open pores.

  11. Synthesis of D-[U-{sup 13}C]Glucal, D-[U-{sup 13}C] Galactal, and L-[U-{sup 13}C]Fucose for NMR structure studies of oligosaccharides

    Energy Technology Data Exchange (ETDEWEB)

    Wu, R.; Unkefer, C.J.; Silks, L.A. III [Los Alamos National Lab., NM (United States)

    1996-12-31

    The role of carbohydrates is well recognized in a variety of important biological phenomena such as cell surface recognition. Recent advances in carbohydrate chemistry, including the development of solid phase synthesis methods, have helped to provide significant quantities of material by offering general protocols for synthesis of well-defined, pure material. However, the study of the solution structure of oligosaccharides by nuclear magnetic resonance techniques have been hampered by the lack of enriched {sup 13}C material. In an effort to help alleviate this situation, we have been interested in the construction of the title compounds from a single economical carbon source, D-[U-{sup 13}C]glucose. Details of the syntheses will be provided.

  12. Zero-quantum stochastic dipolar recoupling in solid state nuclear magnetic resonance.

    Science.gov (United States)

    Qiang, Wei; Tycko, Robert

    2012-09-14

    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 (13)C-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 (13)C 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 (13)C-labeled L-valine powder (at 14.1 T and 28.00 kHz MAS), uniformly (13)C-labeled protein GB1 in microcrystalline form (at 17.6 T and 40.00 kHz MAS), and partially labeled (13)C-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 (13)C-labeled solids.

  13. Electromagnetic properties of inner double walled carbon nanotubes investigated by nuclear magnetic resonance

    KAUST Repository

    Bouhrara, M.

    2013-01-01

    The nuclear magnetic resonance (NMR) analytical technique was used to investigate the double walled carbon nanotubes (DWNTs) electromagnetic properties of inner walls. The local magnetic and electronic properties of inner nanotubes in DWNTs were analyzed using 25% 13C enriched C 60 by which the effect of dipolar coupling could be minimized. The diamagnetic shielding was determined due to the ring currents on outer nanotubes in DWNTs. The NMR chemical shift anisotropy (CSA) spectra and spin-lattice relaxation studies reveal the metallic properties of the inner nanotubes with a signature of the spin-gap opening below 70 K.

  14. Simultaneous Multiagent Hyperpolarized 13C Perfusion Imaging

    DEFF Research Database (Denmark)

    von Morze, Cornelius; Bok, Robert A.; Reed, Galen D.

    2014-01-01

    Purpose: To demonstrate simultaneous hyperpolarization and imaging of three 13C-labeled perfusion MRI contrast agents with dissimilar molecular structures ([13C]urea, [13C]hydroxymethyl cyclopropane, and [13C]t-butanol) and correspondingly variable chemical shifts and physiological characteristic...

  15. Near-zero-field nuclear magnetic resonance

    OpenAIRE

    Ledbetter, Micah; Theis, Thomas; Blanchard, John; Ring, Hattie; Ganssle, Paul; Appelt, Stephan; Bluemich, Bernhard; Pines, Alex; Budker, Dmitry

    2011-01-01

    We investigate nuclear magnetic resonance (NMR) in near-zero-field, where the Zeeman interaction can be treated as a perturbation to the electron mediated scalar interaction (J-coupling). This is in stark contrast to the high field case, where heteronuclear J-couplings are normally treated as a small perturbation. We show that the presence of very small magnetic fields results in splitting of the zero-field NMR lines, imparting considerable additional information to the pure zero-field spectr...

  16. ParaHydrogen Induced Polarization of 13C carboxylate resonance in acetate and pyruvate.

    Science.gov (United States)

    Reineri, Francesca; Boi, Tommaso; Aime, Silvio

    2015-01-05

    The advent of nuclear spins hyperpolarization techniques represents a breakthrough in the field of medical diagnoses by magnetic resonance imaging. Dynamic nuclear polarization (DNP) is the most widely used method, and hyperpolarized metabolites such as [1-(13)C]-pyruvate are shown to report on status of tumours. Parahydrogen-induced polarization (PHIP) is a chemistry-based technique, easier to handle and much less expensive in respect to DNP, with significantly shorter polarization times. Its main limitation is the availability of unsaturated precursors for the target substrates; for instance, acetate and pyruvate cannot be obtained by direct incorporation of the parahydrogen molecule. Herein we report a method that allows us to achieve hyperpolarization in this kind of molecule by means of a tailored precursor containing a hydrogenable functionality that, after polarization transfer to the target (13)C moiety, is cleaved to obtain the metabolite of interest. The reported procedure can be extended to a number of other biologically relevant substrates.

  17. Single crystal nuclear magnetic resonance in spinning powders

    Science.gov (United States)

    Pell, Andrew J.; Pintacuda, Guido; Emsley, Lyndon

    2011-10-01

    We present a method for selectively exciting nuclear magnetic resonances (NMRs) from well-defined subsets of crystallites from a powdered sample under magic angle spinning. Magic angle spinning induces a time dependence in the anisotropic interactions, which results in a time variation of the resonance frequencies which is different for different crystallite orientations. The proposed method exploits this by applying selective pulses, which we refer to as XS (for crystallite-selective) pulses, that follow the resonance frequencies of nuclear species within particular crystallites, resulting in the induced flip angle being orientation dependent. By selecting the radiofrequency field to deliver a 180 ○ pulse for the target orientation and employing a train of such pulses combined with cogwheel phase cycling, we obtain a high degree of orientational selectivity with the resulting spectrum containing only contributions from orientations close to the target. Typically, this leads to the selection of between 0.1% and 10% of the crystallites, and in extreme cases to the excitation of a single orientation resulting in single crystal spectra of spinning powders. Two formulations of this method are described and demonstrated with experimental examples on [1 - 13C]-alanine and the paramagnetic compound Sm2Sn2O7.

  18. magnetic order studied by nuclear methods

    CERN Document Server

    Reichl, C

    2001-01-01

    investigated within the frame of this work. The studies on the highly concentrated deuterides revealed a gradual loss in local field due to a distribution of 'local Curie temperatures' depending on the number of Fe neighbours and their distances from the Moessbauer nucleus. On rising the temperature, during a magnetic transition, an increasing number of Fe sites with different local environment loose their hyperfine fields, whereas bulk measurements showed a relatively sharp, however, incomplete transition. By using a combination of neutron diffraction- and muon spin relaxation studies the complex magnetic phase diagram of the system Ce(Rh,Ru) sub 3 B sub 2 , where weak magnetic moments exist, could be studied. There, transitions from para- to ferromagnetism, and more complicated magnetic structures could be observed. Due to the existence of several isotopes of B and Ru, each carrying different nuclear spins and magnetic moment, particularly complicated second moment simulations for interpreting the muon data...

  19. Nuclear magnetic shieldings of stacked aromatic and antiaromatic molecules.

    Science.gov (United States)

    Sundholm, Dage; Rauhalahti, Markus; Özcan, Nergiz; Mera-Adasme, Raul; Kussmann, Jörg; Luenser, Arne; Ochsenfeld, Christian

    2017-03-13

    Nuclear magnetic shieldings have been calculated at the density functional theory (DFT) level for stacks of benzene, hexadehydro[12]annulene, dodecadehydro[18]annulene and hexabenzocoronene. The magnetic shieldings due to the ring currents in the adjacent molecules have been estimated by calculating nucleus independent molecular shieldings for the monomer in the atomic positions of neighbor molecules. The calculations show that the independent shielding model works reasonable well for the (1)H NMR shieldings of benzene and hexadehydro[12]annulene, whereas for the larger molecules and for the (13)C NMR shieldings the interaction between the molecules leads to shielding effects that are at least of the same size as the ring current contributions from the adjacent molecules. A better agreement is obtained when the nearest neighbors are also considered at full quantum mechanical (QM) level. The calculations suggest that the nearest solvent molecules must be included in the quantum mechanical system, at least when estimating solvent shifts at the molecular mechanics (MM) level. Current density calculations show that the stacking does not significantly affect the ring current strengths of the individual molecules, whereas the shape of the ring current for a single molecule differs from that of the stacked molecules.

  20. Pulsed polarization transfer for 13C NMR in solids

    Science.gov (United States)

    Bax, Ad; Szeverenyi, Nikolaus M.; Maciel, Gary E.

    A new pulsed polarization transfer experiment method is described for the polarization of 13C spins in a solid by magnetization transfer from protons. The method is directly analogous to the INEPT sequence for liquids introduced by Freeman and Morris. As polarization is transferred in PPT between individual 1H 13C pairs, rather than between spin reservoirs, different opportunities exist for structurally selective experiments. Results on p-diethoxybenzene and coronene are presented.

  1. Oxidative stress-induced metabolic changes in mouse C2C12 myotubes studied with high-resolution 13C, 1H, and 31P NMR spectroscopy

    DEFF Research Database (Denmark)

    Straadt, Ida K; Young, Jette F; Petersen, Bent O;

    2010-01-01

    In this study, stress in relation to slaughter was investigated in a model system by the use of (13)C, (1)H, and (31)P nuclear magnetic resonance (NMR) spectroscopy for elucidating changes in the metabolites in C2C12 myotubes exposed to H(2)O(2)-induced stress. Oxidative stress resulted in lower...... to lower levels of the unlabeled ((12)C) lactate were identified in the (1)H spectra after stress exposure. These data indicate an increase in de novo synthesis of alanine, concomitant with a release of lactate from the myotubes to the medium at oxidative stress conditions. The changes in the metabolite...... levels of several metabolites, mainly amino acids; however, higher levels of alanine were apparent in the (13)C spectra after incubation with [(13)C(1)]glucose. In the (13)C spectra [(13)C(3)]lactate tended to increase after exposure to increasing concentrations of H(2)O(2); conversely, a tendency...

  2. Multi-Spectroscopic Analysis of Seed Quality and 13C-Stable-Iotopologue Monitoring in Initial Growth Metabolism of Jatropha curcas L.

    Directory of Open Access Journals (Sweden)

    Takanori Komatsu

    2014-11-01

    Full Text Available In the present study, we applied nuclear magnetic resonance (NMR, as well as near-infrared (NIR spectroscopy, to Jatropha curcas to fulfill two objectives: (1 to qualitatively examine the seeds stored at different conditions, and (2 to monitor the metabolism of J. curcas during its initial growth stage under stable-isotope-labeling condition (until 15 days after seeding. NIR spectra could non-invasively distinguish differences in storage conditions. NMR metabolic analysis of water-soluble metabolites identified sucrose and raffinose family oligosaccharides as positive markers and gluconic acid as a negative marker of seed germination. Isotopic labeling patteren of metabolites in germinated seedlings cultured in agar-plate containg 13C-glucose and 15N-nitrate was analyzed by zero-quantum-filtered-total correlation spectroscopy (ZQF-TOCSY and 13C-detected 1H-13C heteronuclear correlation spectroscopy (HETCOR. 13C-detected HETOCR with 13C-optimized cryogenic probe provided high-resolution 13C-NMR spectra of each metabolite in molecular crowd. The 13C-13C/12C bondmer estimated from 1H-13C HETCOR spectra indicated that glutamine and arginine were the major organic compounds for nitrogen and carbon transfer from roots to leaves.

  3. Synthesis of exemestane labelled with (13)C.

    Science.gov (United States)

    Fontana, Erminia; Pignatti, Alberto; Giribone, Danilo; Di Salle, Enrico

    2008-08-01

    The synthesis of exemestane Aromasin, an irreversible steroidal aromatase inhibitor, specifically labelled with (13)C is reported. The preparation of [(13)C(3)]exemestane was achieved according to an eight-step procedure starting from the commercially available testosterone.

  4. Field dependence of T1 for hyperpolarized [1-13C]pyruvate

    DEFF Research Database (Denmark)

    Chattergoon, N.; Martnez-Santiesteban, F.; Handler, W. B.

    2013-01-01

    conformation and properties of the dissolution media such as buffer composition, solution pH, temperature and magnetic field. We have measured the magnetic field dependence of the spin–lattice relaxation time of hyperpolarized [1-13C]pyruvate using field-cycled relaxometry. [1-13C]pyruvate was hyperpolarized...... using dynamic nuclear polarization and then rapidly thawed and dissolved in a buffered solution to a concentration of 80 mmol l−1 and a pH of ~7.8. The hyperpolarized liquid was transferred within 8 s to a fast field-cycling relaxometer with a probe tuned for detection of 13C at a field strength of ~0...... of pyruvate. Using similar methods, we also determined the relaxivity of the triarylmethyl radical (OX063; used for dynamic nuclear polarization) on the C-1 of pyruvate at field strengths of 0.001, 0.01, 0.1 and 0.5 T using 0.075, 1.0 and 2.0 mmol l−1 concentrations of OX063 in the hyperpolarized pyruvate...

  5. Metabolic origin of the {delta}{sup 13}C of respired CO{sub 2} in roots of Phaseolus vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Bathellier, C.; Tcherkez, G.; Cornic, G.; Ghashghaie, J. [Laboratoire d' Ecologie, Systematique et Evolution - ESE, CNRS-UMR 8079 - IFR 87, Batiment 362, Universite Paris-Sud, 91405-Orsay Cedex (France); Tcherkez, G. [Plateforme Metabolisme-Metabolome, IFR87 La Plante et son Environnement, Institut de Biotechnologie des Plantes, Batiment 630, Universite Paris-Sud, 91405-Orsay Cedex (France); Bligny, R.; Gout, E. [Laboratoire de Physiologie Cellulaire Vegetale CEA-Grenoble 17, rue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2009-07-01

    - Root respiration is a major contributor to soil CO{sub 2} efflux, and thus an important component of ecosystem respiration. But its metabolic origin, in relation to the carbon isotope composition ({delta}{sup 13}C), remains poorly understood. - Here, {sup 13}C analysis was conducted on CO{sub 2} and metabolites under typical conditions or under continuous darkness in French bean (Phaseolus vulgaris) roots. {sup 13}C contents were measured either under natural abundance or following pulse-chase labeling with {sup 13}C-enriched glucose or pyruvate, using isotope ratio mass spectrometer (IRMS) and nuclear magnetic resonance (NMR) techniques. - In contrast to leaves, no relationship was found between the respiratory quotient and the {delta}{sup 13}C of respired CO{sub 2}, which stayed constant at a low value (c. -27.5 per thousand) under continuous darkness. With labeling experiments, it is shown that such a pattern is explained by the {sup 13}C-depleting effect of the pentose phosphate pathway; and the involvement of the Krebs cycle fueled by either the glycolytic input or the lipid/protein recycling. The anaplerotic phosphoenolpyruvate carboxylase (PEPc) activity sustained glutamic acid (Glu) synthesis, with no net effect on respired CO{sub 2}. - These results indicate that the root {delta}{sup 13}C signal does not depend on the availability of root respiratory substrates and it is thus plausible that, unless the {sup 13}C photosynthetic fractionation varies at the leaf level, the root {delta}{sup 13}C signal hardly changes under a range of natural environmental conditions. (authors)

  6. Experimental test of nuclear magnetization distribution and nuclear structure models

    Energy Technology Data Exchange (ETDEWEB)

    Beirsdorfer, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lopez-Urrutia, J Crespo R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Utter, S. B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    1999-02-26

    Models exist that ascribe the nuclear magnetic fields to the presence of a single nucleon whose spin is not neutralized by pairing it up with that of another nucleon; other models assume that the generation of the magnetic field is shared among some or all nucleons throughout the nucleus. All models predict the same magnetic field external to the nucleus since this is an anchor provided by experiments. The models differ, however, in their predictions of the magnetic field arrangement within the nucleus for which no data exist. The only way to distinguish which model gives the correct description of the nucleus would be to use a probe inserted into the nucleus. The goal of our project was to develop exactly such a probe and to use it to measure fundamental nuclear quantities that have eluded experimental scrutiny. The need for accurately knowing such quantities extends far beyond nuclear physics and has ramifications in parity violation experiments on atomic traps and the testing of the standard model in elementary particle physics. Unlike scattering experiments that employ streams of free particles, our technique to probe the internal magnetic field distribution of the nucleus rests on using a single bound electron. Quantum mechanics shows that an electron in the innermost orbital surrounding the nucleus constantly dives into the nucleus and thus samples the fields that exist inside. This sampling of the nucleus usually results in only minute shifts in the electron' s average orbital, which would be difficult to detect. By studying two particular energy states of the electron, we can, however, dramatically enhance the effects of the distribution of the magnetic fields in the nucleus. In fact about 2% of the energy difference between the two states, dubbed the hyperfine splitting, is determined by the effects related to the distribution of magnetic fields in the nucleus, A precise measurement of this energy difference (better than 0.01%) would then allow us to

  7. Determination of alkylbenzenesulfonate surfactants in groundwater using macroreticular resins and carbon-13 nuclear magnetic resonance spectrometry

    Science.gov (United States)

    Thurman, E.M.; Willoughby, T.; Barber, L.B.; Thorn, K.A.

    1987-01-01

    Alkylbenzenesulfonate surfactants were determined in groundwater at concentrations as low as 0.3 mg/L. The method uses XAD-8 resin for concentration, followed by elution with methanol, separation of anionic and nonionic surfactants by anion exchange, quantitation by titration, and identification by 13C nuclear magnetic resonance spectrometry. Laboratory standards and field samples containing straight-chain and branched-chain alkylbenzenesulfonates, sodium dodecyl sulfate, and alkylbenzene ethoxylates were studied. The XAD-8 extraction of surfactants from groundwater was completed in the field, which simplified sample preservation and reduced the cost of transporting samples.

  8. Study of molecular interactions with 13C DNP-NMR.

    Science.gov (United States)

    Lerche, Mathilde H; Meier, Sebastian; Jensen, Pernille R; Baumann, Herbert; Petersen, Bent O; Karlsson, Magnus; Duus, Jens Ø; Ardenkjaer-Larsen, Jan H

    2010-03-01

    NMR spectroscopy is an established, versatile technique for the detection of molecular interactions, even when these interactions are weak. Signal enhancement by several orders of magnitude through dynamic nuclear polarization alleviates several practical limitations of NMR-based interaction studies. This enhanced non-equilibrium polarization contributes sensitivity for the detection of molecular interactions in a single NMR transient. We show that direct (13)C NMR ligand binding studies at natural isotopic abundance of (13)C gets feasible in this way. Resultant screens are easy to interpret and can be performed at (13)C concentrations below muM. In addition to such ligand-detected studies of molecular interaction, ligand binding can be assessed and quantified with enzymatic assays that employ hyperpolarized substrates at varying enzyme inhibitor concentrations. The physical labeling of nuclear spins by hyperpolarization thus provides the opportunity to devise fast novel in vitro experiments with low material requirement and without the need for synthetic modifications of target or ligands.

  9. The Branchings of the Main s-process: Their Sensitivity to alpha-induced Reactions on 13C and 22Ne and to the Uncertainties of the Nuclear Network

    CERN Document Server

    Bisterzo, Sara; Kaeppeler, Franz; Wiescher, Michael; Imbriani, Gianluca; Straniero, Oscar; Cristallo, Sergio; Goerres, Joachim; deBoer, Richard

    2015-01-01

    This paper provides a detailed analysis of the main component of the slow neutron capture process (the s-process), which accounts for the solar abundances of half of the nuclei with 90 <~ A <~ 208. We examine the impact of the uncertainties of the two neutron sources operating in low-mass asymptotic giant branch (AGB) stars: the 13C(alpha, n)16O reaction, which releases neutrons radiatively during interpulse periods (kT ~ 8 keV), and the 22Ne(alpha, n)25Mg reaction, partially activated during the convective thermal pulses (TPs). We focus our attention on the branching points that mainly influence the abundance of s-only isotopes. In our AGB models, the 13C is fully consumed radiatively during interpulse. In this case, we find that the present uncertainty associated to the 13C(alpha, n)16O reaction has marginal effects on s-only nuclei. On the other hand, a reduction of this rate may increase the amount of residual (or unburned) 13C at the end of the interpulse: in this condition, the residual 13C is bur...

  10. 13C Tracking after 13CO2 Supply Revealed Diurnal Patterns of Wood Formation in Aspen.

    Science.gov (United States)

    Mahboubi, Amir; Linden, Pernilla; Hedenström, Mattias; Moritz, Thomas; Niittylä, Totte

    2015-06-01

    Wood of trees is formed from carbon assimilated in the photosynthetic tissues. Determining the temporal dynamics of carbon assimilation, subsequent transport into developing wood, and incorporation to cell walls would further our understanding of wood formation in particular and tree growth in general. To investigate these questions, we designed a (13)CO2 labeling system to study carbon transport and incorporation to developing wood of hybrid aspen (Populus tremula × tremuloides). Tracking of (13)C incorporation to wood over a time course using nuclear magnetic resonance spectroscopy revealed diurnal patterns in wood cell wall biosynthesis. The dark period had a differential effect on (13)C incorporation to lignin and cell wall carbohydrates. No (13)C was incorporated into aromatic amino acids of cell wall proteins in the dark, suggesting that cell wall protein biosynthesis ceased during the night. The results show previously unrecognized temporal patterns in wood cell wall biosynthesis, suggest diurnal cycle as a possible cue in the regulation of carbon incorporation to wood, and establish a unique (13)C labeling method for the analysis of wood formation and secondary growth in trees.

  11. Partial least squares modeling of combined infrared, 1H NMR and 13C NMR spectra to predict long residue properties of crude oils

    NARCIS (Netherlands)

    de Peinder, P.|info:eu-repo/dai/nl/325810818; Visser, T.|info:eu-repo/dai/nl/110288327; Petrauskas, D.D.; Salvatori, F.; Soulimani, F.|info:eu-repo/dai/nl/313889449; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397

    2009-01-01

    Research has been carried out to determine the potential of partial least squares (PLS) modeling of mid-infrared (IR) spectra of crude oils combined with the corresponding 1H and 13C nuclear magnetic resonance (NMR) data, to predict the long residue (LR) properties of these substances. The study

  12. Evaluating pyrolysis-GC/MS and 13C CPMAS NMR in conjunction with a molecular mixing model of the Penido Vello peat deposit, NW Spain

    NARCIS (Netherlands)

    Kaal, J.; Baldock, J.A.; Buurman, P.; Nierop, K.G.J.; Pontevedra-Pombal, X.; Martínez-Cortizas, A.

    2007-01-01

    We performed solid state 13C cross-polarization magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectroscopy and pyrolysis¿gas chromatography/mass spectrometry (Py¿GC/MS) on the Penido Vello peat deposit located in Galicia, NW Spain. Often regarded as complementary techniques, solid st

  13. Regio-selective detection of dynamic structure of transmembrane alpha-helices as revealed from (13)C NMR spectra of [3-13C]Ala-labeled bacteriorhodopsin in the presence of Mn2+ ion.

    Science.gov (United States)

    Tuzi, S; Hasegawa, J; Kawaminami, R; Naito, A; Saitô, H

    2001-07-01

    13C Nuclear magnetic resonance (NMR) spectra of [3-(13)C]Ala-labeled bacteriorhodopsin (bR) were edited to give rise to regio-selective signals from hydrophobic transmembrane alpha-helices by using NMR relaxation reagent, Mn(2+) ion. As a result of selective suppression of (13)C NMR signals from the surfaces in the presence of Mn(2+) ions, several (13)C NMR signals of Ala residues in the transmembrane alpha-helices were identified on the basis of site-directed mutagenesis without overlaps from (13)C NMR signals of residues located near the bilayer surfaces. The upper bound of the interatomic distances between (13)C nucleus in bR and Mn(2+) ions bound to the hydrophilic surface to cause suppressed peaks by the presence of Mn(2+) ion was estimated as 8.7 A to result in the signal broadening to 100 Hz and consistent with the data based on experimental finding. The Ala C(beta) (13)C NMR peaks corresponding to Ala-51, Ala-53, Ala-81, Ala-84, and Ala-215 located around the extracellular half of the proton channel and Ala-184 located at the kink in the helix F were successfully identified on the basis of (13)C NMR spectra of bR in the presence of Mn(2+) ion and site-directed replacement of Ala by Gly or Val. Utilizing these peaks as probes to observe local structure in the transmembrane alpha-helices, dynamic conformation of the extracellular half of bR at ambient temperature was examined, and the local structures of Ala-215 and 184 were compared with those elucidated at low temperature. Conformational changes in the transmembrane alpha-helices induced in D85N and E204Q and its long-range transmission from the proton release site to the site around the Schiff base in E204Q were also examined.

  14. Synthesis of /sup 13/C-labelled medroxyprogesterone acetate with three /sup 13/C isotopes (1)

    Energy Technology Data Exchange (ETDEWEB)

    Rao, P.N.; Damodaran, K.M. (Southwest Foundation for Research and Education, San Antonio, TX (USA))

    1982-03-01

    17..cap alpha..-hydroxyprogesterone was condensed with phenyl acetate /sup 13/C/sub 2/ in the presence of sodium hydride. Treatment with acetic and hydrochloric acids and acetylation gave 17..cap alpha..-acetoxyprogesterone /sup 13/C/sub 2/. Treatment with tetrabromomethane /sup 13/C and hydrogenation yielded medroxyprogesterone acetate with three /sup 13/C isotopes.

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

    Science.gov (United States)

    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.

  16. Structural characteristics of marine sedimentary humic acids by CP/MAS sup(13)C NMR spectroscopy

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.; Wahidullah, S.

    stream_size 34319 stream_content_type text/plain stream_name Oceanol_Acta_21_543.pdf.txt stream_source_info Oceanol_Acta_21_543.pdf.txt Content-Encoding UTF-8 Content-Type text/plain; charset=UTF-8 OCEANOLOGICA ACTA... components of the: hydrolysate. 545 S. SARDESSAI, S. WAHlDULLAH 3.3 Nuclear magnetic resonance ~pe~t~Q~cQQy The cross-polarization technique with magic angle spin- ning (CP/MAS) was used to obtain 13C NMR spectra. Samples were thoroughly freeze...

  17. (13)C and (15)N solid-state NMR studies on albendazole and cyclodextrin albendazole complexes.

    Science.gov (United States)

    Ferreira, M João G; García, A; Leonardi, D; Salomon, Claudio J; Lamas, M Celina; Nunes, Teresa G

    2015-06-05

    (13)C and (15)N solid-state nuclear magnetic resonance (NMR) spectra were recorded from albendazole (ABZ) and from ABZ:β-cyclodextrin, ABZ:methyl-β-cyclodextrin, ABZ:hydroxypropyl-β-cyclodextrin and ABZ:citrate-β-cyclodextrin, which were prepared by the spray-drying technique. ABZ signals were typical of a crystalline solid for the pure drug and of an amorphous compound obtained from ABZ:cyclodextrin samples. Relevant spectral differences were correlated with chemical interaction between ABZ and cyclodextrins. The number and type of complexes revealed a strong dependence on the cyclodextrin group substituent. Solid-state NMR data were consistent with the presence of stable inclusion complexes.

  18. Novel nuclear magnetic resonance techniques for studying biological molecules

    Energy Technology Data Exchange (ETDEWEB)

    Laws, David D.

    2000-06-01

    Over the fifty-five year history of Nuclear Magnetic Resonance (NMR), considerable progress has been made in the development of techniques for studying the structure, function, and dynamics of biological molecules. The majority of this research has involved the development of multi-dimensional NMR experiments for studying molecules in solution, although in recent years a number of groups have begun to explore NMR methods for studying biological systems in the solid-state. Despite this new effort, a need still exists for the development of techniques that improve sensitivity, maximize information, and take advantage of all the NMR interactions available in biological molecules. In this dissertation, a variety of novel NMR techniques for studying biomolecules are discussed. A method for determining backbone ({phi}/{psi}) dihedral angles by comparing experimentally determined {sup 13}C{sub a}, chemical-shift anisotropies with theoretical calculations is presented, along with a brief description of the theory behind chemical-shift computation in proteins and peptides. The utility of the Spin-Polarization Induced Nuclear Overhauser Effect (SPINOE) to selectively enhance NMR signals in solution is examined in a variety of systems, as are methods for extracting structural information from cross-relaxation rates that can be measured in SPINOE experiments. Techniques for the production of supercritical and liquid laser-polarized xenon are discussed, as well as the prospects for using optically pumped xenon as a polarizing solvent. In addition, a detailed study of the structure of PrP 89-143 is presented. PrP 89-143 is a 54 residue fragment of the prion proteins which, upon mutation and aggregation, can induce prion diseases in transgenic mice. Whereas the structure of the wild-type PrP 89-143 is a generally unstructured mixture of {alpha}-helical and {beta}-sheet conformers in the solid state, the aggregates formed from the PrP 89-143 mutants appear to be mostly {beta}-sheet.

  19. {sup 13}C NMR and EPR spectroscopic evaluation of oil shale mined soil recuperation

    Energy Technology Data Exchange (ETDEWEB)

    Santos, J.V. dos, E-mail: mangrich@ufpr.br [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil); Mangrich, A.S. [Instituto Nacional de Ciencia e Tecnologia: Energia e Ambiente, Salvador, BA (Brazil); Pereira, B.F. [EMBRAPA Clima Temperado, Pelotas, RS (Brazil); Pillon, C.N. [EMBRAPA Clima Temperado, Pelotas, RS (Brazil). Estacao Experimental Cascata; Novotny, E.H. [EMBRAPA Solos, Rio de Janeiro, RJ (Brazil); Bonagamba, T.J. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Instituto de Fisica; Abbt-Braun, G.; Frimmel, F.H. [Engler-Bunte-Institut, Universitaet Karlsruhe, TH (Germany)

    2013-02-15

    In this work, native forest soil (NFS) organic matter (SOM) sample and SOM samples from a neighboring forest soil area of an oil shale mine which is being rehabilitated for thirty years (RFS) were analyzed. X-band electron paramagnetic resonance (EPR) and solid-state {sup 13}C nuclear magnetic resonance (NMR) spectroscopies were used to evaluate the soil reclamation of the Brazilian oil shale mining process. Two-dimensional heterospectral correlation studies of the results obtained from EPRand {sup 13}C NMR were used to obtain information about SOM structures and their interactions with residual paramagnetic metal ion. The signal of the residual metallic oxycation, VO{sup 2+} correlated positively with uronic acid-type hydrophilic organic structures, determined from the {sup 13}C NMR spectra, and correlated negatively with the organic free radical (OFR) signal associated with oxygen atoms (g = 2.0042). The hydrophobic aromatic structures correlate positively with the EPR OFR signal associated with carbon atoms (g = 2.0022). The data from the two spectroscopic magnetic techniques show that the used recuperation process is effective. (author)

  20. Near-zero-field nuclear magnetic resonance

    CERN Document Server

    Ledbetter, Micah; Blanchard, John; Ring, Hattie; Ganssle, Paul; Appelt, Stephan; Bluemich, Bernhard; Pines, Alex; Budker, Dmitry

    2011-01-01

    We investigate nuclear magnetic resonance (NMR) in near-zero-field, where the Zeeman interaction can be treated as a perturbation to the electron mediated scalar interaction (J-coupling). This is in stark contrast to the high field case, where heteronuclear J-couplings are normally treated as a small perturbation. We show that the presence of very small magnetic fields results in splitting of the zero-field NMR lines, imparting considerable additional information to the pure zero-field spectra. Experimental results are in good agreement with first-order perturbation theory and with full numerical simulation when perturbation theory breaks down. We present simple rules for understanding the splitting patterns in near-zero-field NMR, which can be applied to molecules with non-trivial spectra.

  1. Near-zero-field nuclear magnetic resonance.

    Science.gov (United States)

    Ledbetter, M P; Theis, T; Blanchard, J W; Ring, H; Ganssle, P; Appelt, S; Blümich, B; Pines, A; Budker, D

    2011-09-02

    We investigate nuclear magnetic resonance (NMR) in near zero field, where the Zeeman interaction can be treated as a perturbation to the electron mediated scalar interaction (J coupling). This is in stark contrast to the high-field case, where heteronuclear J couplings are normally treated as a small perturbation. We show that the presence of very small magnetic fields results in splitting of the zero-field NMR lines, imparting considerable additional information to the pure zero-field spectra. Experimental results are in good agreement with first-order perturbation theory and with full numerical simulation when perturbation theory breaks down. We present simple rules for understanding the splitting patterns in near-zero-field NMR, which can be applied to molecules with nontrivial spectra.

  2. Nanoscale nuclear magnetic resonance with chemical resolution

    Science.gov (United States)

    Aslam, Nabeel; Pfender, Matthias; Neumann, Philipp; Reuter, Rolf; Zappe, Andrea; Fávaro de Oliveira, Felipe; Denisenko, Andrej; Sumiya, Hitoshi; Onoda, Shinobu; Isoya, Junichi; Wrachtrup, Jörg

    2017-07-01

    Nuclear magnetic resonance (NMR) spectroscopy is a key analytical technique in chemistry, biology, and medicine. However, conventional NMR spectroscopy requires an at least nanoliter-sized sample volume to achieve sufficient signal. We combined the use of a quantum memory and high magnetic fields with a dedicated quantum sensor based on nitrogen vacancy centers in diamond to achieve chemical shift resolution in 1H and 19F NMR spectroscopy of 20-zeptoliter sample volumes. We demonstrate the application of NMR pulse sequences to achieve homonuclear decoupling and spin diffusion measurements. The best measured NMR linewidth of a liquid sample was ~1 part per million, mainly limited by molecular diffusion. To mitigate the influence of diffusion, we performed high-resolution solid-state NMR by applying homonuclear decoupling and achieved a 20-fold narrowing of the NMR linewidth.

  3. C nuclear magnetic resonance study of acetate incorporation into malate during ca-uptake by isolated leaf tissues.

    Science.gov (United States)

    Borchert, R; Everett, G W

    1987-07-01

    (13)C Nuclear magnetic resonance spectroscopy of leaflets of Gleditsia triacanthos and Albizia julibrisin was used to determine the fate of acetate taken up during the absorption of calcium from (13)C-labeled Ca-acetate solution. Small amounts of acetate accumulated temporarily in the leaf tissues, but the bulk of acetate was incorporated into malate. The initial rate of malate synthesis was very low, but increased rapidly during acetate treatment and reached its maximum after 8 hours; the enzymes involved in malate synthesis thus appear to be substrate induced. Use of acetate-2-(13)C yielded malate labeled in C-3, indicating that vacuolar malate accumulating during Ca-uptake might be synthesized via malate synthase from acetate and glyoxalate. However, a source of glyoxalate condensing with acetate during malate synthesis could not be identified. Glycolate produced in photorespiration is an unlikely source, because glycolate-2-(13)C was absorbed and metabolized by the leaf tissues into products of the glycolate pathway, but was not a major precursor in malate synthesis. Malate synthesis via the glyoxalate cycle is also unlikely, because no evidence for the recycling of a (13)C-labeled 4-carbon organic acid was found. Malate synthesis in the leaflets of Gleditsia and Albizia thus appears to involve the inducible condensation of acetate with a 2-carbon compound of unidentified nature and origin.

  4. Theoretical Study of H/D Isotope Effects on Nuclear Magnetic Shieldings Using an ab initio Multi-Component Molecular Orbital Method

    Directory of Open Access Journals (Sweden)

    Masanori Tachikawa

    2013-05-01

    Full Text Available We have theoretically analyzed the nuclear quantum effect on the nuclear magnetic shieldings for the intramolecular hydrogen-bonded systems of σ-hydroxy acyl aromatic species using the gauge-including atomic orbital technique combined with our multi-component density functional theory. The effect of H/D quantum nature for geometry and nuclear magnetic shielding changes are analyzed. Our study clearly demonstrated that the geometrical changes of hydrogen-bonds induced by H/D isotope effect (called geometrical isotope effect: GIE is the dominant factor of deuterium isotope effect on 13C chemical shift.

  5. Microsolvation of methylmercury: structures, energies, bonding and NMR constants ((199)Hg, (13)C and (17)O).

    Science.gov (United States)

    Flórez, Edison; Maldonado, Alejandro F; Aucar, Gustavo A; David, Jorge; Restrepo, Albeiro

    2016-01-21

    Hartree-Fock (HF) and second order perturbation theory (MP2) calculations within the scalar and full relativistic frames were carried out in order to determine the equilibrium geometries and interaction energies between cationic methylmercury (CH3Hg(+)) and up to three water molecules. A total of nine structures were obtained. Bonding properties were analyzed using the Quantum Theory of Atoms In Molecules (QTAIM). The analyses of the topology of electron densities reveal that all structures exhibit a partially covalent HgO interaction between methylmercury and one water molecule. Consideration of additional water molecules suggests that they solvate the (CH3HgOH2)(+) unit. Nuclear magnetic shielding constants σ((199)Hg), σ((13)C) and σ((17)O), as well as indirect spin-spin coupling constants J((199)Hg-(13)C), J((199)Hg-(17)O) and J((13)C-(17)O), were calculated for each one of the geometries. Thermodynamic stability and the values of NMR constants correlate with the ability of the system to directly coordinate oxygen atoms of water molecules to the mercury atom in methylmercury and with the formation of hydrogen bonds among solvating water molecules. Relativistic effects account for 11% on σ((13)C) and 14% on σ((17)O), which is due to the presence of Hg (heavy atom on light atom, HALA effect), while the relativistic effects on σ((199)Hg) are close to 50% (heavy atom on heavy atom itself, HAHA effect). J-coupling constants are highly influenced by relativity when mercury is involved as in J((199)Hg-(13)C) and J((199)Hg-(17)O). On the other hand, our results show that the values of NMR constants for carbon and oxygen, atoms which are connected through mercury (C-HgO), are highly correlated and are greatly influenced by the presence of water molecules. Water molecules introduce additional electronic effects to the relativistic effects due to the mercury atom.

  6. Experiments in Nuclear Magnetic Resonance Microscopy

    Science.gov (United States)

    Lee, Yong; Lu, Wei; Choi, J.-H.; Chia, H. J.; Mirsaidov, U. M.; Guchhait, S.; Cambou, A. D.; Cardenas, R.; Park, K.; Markert, J. T.

    2006-03-01

    We report our group's effort in the construction of an 8-T, ^3 He cryostat based nuclear magnetic resonance force microscope (NMRFM). The probe has two independent 3-D of piezoelectric x-y-z positioners for precise positioning of a fiber optic interferometer and a sample/gradient-producing magnet with respect to a micro-cantilever. The piezoelectric positioners have a very uniform controllable step size with virtually no backlash. A novel RF tuning circuit board design is implemented which allows us to simply swap out one RF component board with another for experiments involving different nuclear species. We successfully fabricated and are characterizing 50μm x50μm x0.2μm double torsional oscillators. We have also been characterizing ultrasoft cantilevers whose spring constant is on the order of 10-4 N/m. We also report NMRFM data for ammonium dihydrogen phosphate(ADP) at room temperature using our 1.2-T system. Observed features include the correct shift of the NMR peak with carrier frequency, increases in signal amplitude with both RF field strength and frequency modulation amplitude, and signal oscillation (spin nutation) as a function of tipping RF pulse length. Experiments in progress on NH4MgF3 (at 1.2 T) and MgB2 (at 8.1 T) will also be briefly reviewed. Robert A. Welch Foundation grant No.F-1191 and the National Science Foundation grant No. DMR-0210383.

  7. Fourier Transform Microwave Spectroscopy of Sc13C2 and Sc12C13C: Establishing AN Accurate Structure of ScC2 (tilde{X}2A1)

    Science.gov (United States)

    Burton, Mark; Halfen, DeWayne T.; Min, Jie; Ziurys, Lucy M.

    2016-06-01

    Pure rotational spectra of Sc13C2 and Sc12C13C (tilde{X}2A1) have been obtained using Fourier Transform Microwave methods. These molecules were created from scandium vapor in combination with 13CH4 and/or 12CH4, diluted in argon, using a Discharge Assisted Laser Ablation Source (DALAS). Transitions in the frequency range of 14-30 GHz were observed for both species including hyperfine splitting due to the nuclear spin of Sc (I = 7/2) and 13C (I = 1/2). Rotational, spin-rotational, and hyperfine constants have been determined for Sc13C2 and Sc12C13C, as well as a refined structure for ScC2. In agreement with theoretical calculations and previous Sc12C2 results, these data confirm a cyclic (or T-shaped) structure for this molecule. Scandium carbides have been shown to form endohedral-doped fullerenes, which have unique electrical and magnetic properties due to electron transfer between the metal and the carbon-cage. Spectroscopy of ScC2 provides data on model systems for comparison with theory.

  8. Zero-quantum frequency-selective recoupling of homonuclear dipole-dipole interactions in solid state nuclear magnetic resonance.

    Science.gov (United States)

    Hu, Kan-Nian; Tycko, Robert

    2009-07-28

    We describe a method for measuring magnetic dipole-dipole interactions, and hence distances, between pairs of like nuclear spins in a many-spin system under magic-angle spinning (MAS). This method employs a homonuclear dipolar recoupling sequence that creates an average dipole-dipole coupling Hamiltonian under MAS with full zero-quantum symmetry, including both secular and flip-flop terms. Flip-flop terms are then attenuated by inserting rotor-synchronized periods of chemical shift evolution between recoupling blocks, leaving an effective Hamiltonian that contains only secular terms to a good approximation. Couplings between specific pairs of nuclear spins can then be selected with frequency-selective pi pulses. We demonstrate this technique, which we call zero-quantum shift evolution assisted homonuclear recoupling, in a series of one-dimensional and two-dimensional (13)C NMR experiments at 17.6 T and 40.00 kHz MAS frequency on uniformly (13)C-labeled L-threonine powder and on the helix-forming peptide MB(i+4)EK, synthesized with a pair of uniformly (13)C-labeled L-alanine residues. Experimental demonstrations include measurements of distances between (13)C sites that are separated by three bonds, placing quantitative constraints on both sidechain and backbone torsion angles in polypeptides.

  9. Solid-, Solution-, and Gas-state NMR Monitoring of 13C-Cellulose Degradation in an Anaerobic Microbial Ecosystem

    Directory of Open Access Journals (Sweden)

    Yasuhiro Date

    2013-07-01

    Full Text Available Anaerobic digestion of biomacromolecules in various microbial ecosystems is influenced by the variations in types, qualities, and quantities of chemical components. Nuclear magnetic resonance (NMR spectroscopy is a powerful tool for characterizing the degradation of solids to gases in anaerobic digestion processes. Here we describe a characterization strategy using NMR spectroscopy for targeting the input solid insoluble biomass, catabolized soluble metabolites, and produced gases. 13C-labeled cellulose produced by Gluconacetobacter xylinus was added as a substrate to stirred tank reactors and gradually degraded for 120 h. The time-course variations in structural heterogeneity of cellulose catabolism were determined using solid-state NMR, and soluble metabolites produced by cellulose degradation were monitored using solution-state NMR. In particular, cooperative changes between the solid NMR signal and 13C-13C/13C-12C isotopomers in the microbial degradation of 13C-cellulose were revealed by a correlation heat map. The triple phase NMR measurements demonstrated that cellulose was anaerobically degraded, fermented, and converted to methane gas from organic acids such as acetic acid and butyric acid.

  10. Probing site-specific 13C/15N-isotope enrichment of spider silk with liquid-state NMR spectroscopy.

    Science.gov (United States)

    Shi, Xiangyan; Yarger, Jeffery L; Holland, Gregory P

    2013-05-01

    Solid-state nuclear magnetic resonance (NMR) has been extensively used to elucidate spider silk protein structure and dynamics. In many of these studies, site-specific isotope enrichment is critical for designing particular NMR methods for silk structure determination. The commonly used isotope analysis techniques, isotope-ratio mass spectroscopy and liquid/gas chromatography-mass spectroscopy, are typically not capable of providing the site-specific isotope information for many systems because an appropriate sample derivatization method is not available. In contrast, NMR does not require any sample derivatization or separation prior to analysis. In this article, conventional liquid-state (1)H NMR was implemented to evaluate incorporation of (13)C/(15)N-labeled amino acids in hydrolyzed spider dragline silk. To determine site-specific (13)C and (15)N isotope enrichments, an analysis method was developed to fit the (1)H-(13)C and (1)H-(15)N J-splitting (J CH and J NH) (1)H NMR peak patterns of hydrolyzed silk fiber. This is demonstrated for Nephila clavipes spiders, where [U-(13)C3,(15)N]-Ala and [1-(13)C,(15)N]-Gly were dissolved in their water supplies. Overall, contents for Ala and Gly isotopomers are extracted for these silk samples. The current methodology can be applied to many fields where site-specific tracking of isotopes is of interest.

  11. Spatial localization in nuclear magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Keevil, Stephen F [Department of Medical Physics, Guy' s and St Thomas' NHS Foundation Trust, Guy' s Hospital, London, SE1 9RT (United Kingdom); Division of Imaging Sciences, King' s College London, Guy' s Campus, London, SE1 9RT (United Kingdom)

    2006-08-21

    The ability to select a discrete region within the body for signal acquisition is a fundamental requirement of in vivo NMR spectroscopy. Ideally, it should be possible to tailor the selected volume to coincide exactly with the lesion or tissue of interest, without loss of signal from within this volume or contamination with extraneous signals. Many techniques have been developed over the past 25 years employing a combination of RF coil properties, static magnetic field gradients and pulse sequence design in an attempt to meet these goals. This review presents a comprehensive survey of these techniques, their various advantages and disadvantages, and implications for clinical applications. Particular emphasis is placed on the reliability of the techniques in terms of signal loss, contamination and the effect of nuclear relaxation and J-coupling. The survey includes techniques based on RF coil and pulse design alone, those using static magnetic field gradients, and magnetic resonance spectroscopic imaging. Although there is an emphasis on techniques currently in widespread use (PRESS, STEAM, ISIS and MRSI), the review also includes earlier techniques, in order to provide historical context, and techniques that are promising for future use in clinical and biomedical applications. (topical review)

  12. Comparative study of ¹³C composition in ethanol and bulk dry wine using isotope ratio monitoring by mass spectrometry and by nuclear magnetic resonance as an indicator of vine water status.

    Science.gov (United States)

    Guyon, Francois; van Leeuwen, Cornelis; Gaillard, Laetitia; Grand, Mathilde; Akoka, Serge; Remaud, Gérald S; Sabathié, Nathalie; Salagoïty, Marie-Hélène

    2015-12-01

    The potential of wine (13)C isotope composition (δ(13)C) is presented to assess vine water status during grape ripening. Measurements of δ(13)C have been performed on a set of 32 authentic wines and their ethanol recovered after distillation. The data, obtained by isotope ratio monitoring by mass spectrometry coupled to an elemental analyser (irm-EA/MS), show a high correlation between δ(13)C of the bulk wine and its ethanol, indicating that the distillation step is not necessary when the wine has not been submitted to any oenological treatment. Therefore, the ethanol/wine δ(13)C correlation can be used as an indicator of possible enrichment of the grape must or the wine with exogenous organic compounds. Wine ethanol δ(13)C is correlated to predawn leaf water potential (R(2) = 0.69), indicating that this parameter can be used as an indicator of vine water status. Position-specific (13)C analysis (PSIA) of ethanol extracted from wine, performed by isotope ratio monitoring by nuclear magnetic resonance (irm-(13)C NMR), confirmed the non-homogenous repartition of (13)C on ethanol skeleton. It is the δ(13)C of the methylene group of ethanol, compared to the methyl moiety, which is the most correlated to predawn leaf water potential, indicating that a phase of photorespiration of the vine during water stress period is most probably occurring due to stomata closure. However, position-specific (13)C analysis by irm-(13)C NMR does not offer a greater precision in the assessment of vine water status compared to direct measurement of δ(13)C on bulk wine by irm-EA/MS.

  13. Residual Dipolar Couplings in Zero-to-Ultra-Low-Field Nuclear Magnetic Resonance

    CERN Document Server

    Blanchard, John W; King, Jonathan P; Ledbetter, Micah P; Levine, Emma H; Bajaj, Vikram S; Budker, Dmitry; Pines, Alexander

    2015-01-01

    Zero-to-ultra-low-field nuclear magnetic resonance (ZULF-NMR) provides a new regime for the measurement of nuclear spin-spin interactions free from effects of large magnetic fields, such as truncation of terms that do not commute with the Zeeman Hamiltonian. One such interaction, the magnetic dipole-dipole coupling, is a valuable source of spatial information in NMR, though many terms are unobservable in high-field NMR, and the interaction averages to zero under isotropic molecular tumbling. Under partial orientational ordering, this information is retained in the form of so-called residual dipolar couplings. We report zero-to-ultra-low-field NMR measurements of residual dipolar couplings in acetonitrile-2-$^{13}$C aligned in stretched polyvinyl acetate gels. This represents the first investigation of dipolar couplings as a perturbation on the indirect spin-spin $J$-coupling in the absence of an applied magnetic field. As a consequence of working at zero magnetic field, we observe terms of the dipole-dipole c...

  14. Quantum information processing through nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Bulnes, J.D.; Sarthour, R.S.; Oliveira, I.S. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Bonk, F.A.; Azevedo, E.R. de; Bonagamba, T.J. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Fisica; Freitas, J.C.C. [Espirito Santo Univ., Vitoria, ES (Brazil). Dept. de Fisica

    2005-09-15

    We discuss the applications of Nuclear Magnetic Resonance (NMR) to quantum information processing, focusing on the use of quadrupole nuclei for quantum computing. Various examples of experimental implementation of logic gates are given and compared to calculated NMR spectra and their respective density matrices. The technique of Quantum State Tomography for quadrupole nuclei is briefly described, and examples of measured density matrices in a two-qubit I = 3/2 spin system are shown. Experimental results of density matrices representing pseudo-Bell states are given, and an analysis of the entropy of theses states is made. Considering an NMR experiment as a depolarization quantum channel we calculate the entanglement fidelity and discuss the criteria for entanglement in liquid state NMR quantum information. A brief discussion on the perspectives for NMR quantum computing is presented at the end. (author)

  15. Quantum information processing and nuclear magnetic resonance

    CERN Document Server

    Cummins, H K

    2001-01-01

    as spectrometer pulse sequence programs. Quantum computers are information processing devices which operate by and exploit the laws of quantum mechanics, potentially allowing them to solve problems which are intractable using classical computers. This dissertation considers the practical issues involved in one of the more successful implementations to date, nuclear magnetic resonance (NMR). Techniques for dealing with systematic errors are presented, and a quantum protocol is implemented. Chapter 1 is a brief introduction to quantum computation. The physical basis of its efficiency and issues involved in its implementation are discussed. NMR quantum information processing is reviewed in more detail in Chapter 2. Chapter 3 considers some of the errors that may be introduced in the process of implementing an algorithm, and high-level ways of reducing the impact of these errors by using composite rotations. Novel general expressions for stabilising composite rotations are presented in Chapter 4 and a new class o...

  16. Nuclear magnetic resonance imaging of the spine

    Energy Technology Data Exchange (ETDEWEB)

    Modic, M.T.; Weinstein, M.A.; Pavlicek, W.; Starnes, D.L.; Duchesneau, P.M.; Boumphrey, F.; Hardy, R.J. Jr.

    1984-01-01

    Forty subjects were examined to determine the accuracy and clinical usefulness of nuclear magnetic resonance (NMR) examination of the spine. The NMR images were compared with plain radiographs, high-resolution computed tomograms, and myelograms. The study included 15 patients with normal spinal cord anatomy and 25 patients whose pathological conditions included canal stenosis, herniated discs, metastatic tumors, primary cord tumor, trauma, Chiari malformations, syringomyelia, and developmental disorders. Saturation recovery images were best in differentiating between soft tissue and cerebrospinal fluid. NMR was excellent for the evaluation of the foramen magnum region and is presently the modality of choice for the diagnosis of syringomyelia and Chiari malformation. NMR was accurate in diagnosing spinal cord trauma and spinal canal block.

  17. Neutron halo state of 13C

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Angular distributions for the 12C(d, p)13C transfer reactionshave been measured at Ed = 11.8 MeV, and compared with those of the DWBA calculations. By means of this comparison, density distributions of the last neutron in the ground state and the first 1/2+ state of 13C are extracted. The properties of these states in 13C have also been studied in the framework of the nonlinear relativistic mean-field theory with NL-SH parameters. It is found that the first 1/2+ state in 13C is a neutron halo state shown by both the experimental and theoretical density distributions of the last neutron.

  18. Quantification of protein secondary structure by (13)C solid-state NMR.

    Science.gov (United States)

    Andrade, Fabiana Diuk; Forato, Lucimara Aparecida; Bernardes Filho, Rubens; Colnago, Luiz Alberto

    2016-05-01

    High-resolution (13)C solid-state NMR stands out as one of the most promising techniques to solve the structure of insoluble proteins featuring biological and technological importance. The simplest nuclear magnetic resonance (NMR) spectroscopy method to quantify the secondary structure of proteins uses the areas of carbonyl and alpha carbon peaks. The quantification obtained by fitting procedures depends on the assignment of the peaks to the structure, type of line shape, number of peaks to be used, and other parameters that are set by the operator. In this paper, we demonstrate that the analysis of (13)C NMR spectra by a pattern recognition method-based on the singular value decomposition (SVD) regression, which does not depend on the operator-shows higher correlation coefficients for α-helix and β-sheet (0.96 and 0.91, respectively) than Fourier transform infrared spectroscopy (FTIR) method. Therefore, the use of (13)C solid-state NMR spectra and SVD is a simple and reliable method for quantifying the secondary structures of insoluble proteins in solid-state.

  19. Synthesis of Gemcitabine-13C, 15N2 and Gemcitabine-13C, 15N2 Metabolites

    Directory of Open Access Journals (Sweden)

    ZHU Cheng-gu;YANG Shao-zu;YAN Sheng-wang;FANG Ning-jing;CAI Ding-long;LI Gang

    2014-02-01

    Full Text Available Homemade urea-13C, 15N2 was used to react with 3-methyl acrylonitrile closure to form cytosine-13C, 15N2 (2,which was protected by trimethylsilylation with BSA and condensed with 2-deoxy-2,2-difluoro-D-erythro-pentofuranose-3,5-dibenzoate-1-methanesulfonate at 120 ℃ to afford blocked gemcitabine-13C, 15N2. Hydrolytic removal of the blocking groups of gemcitabine-13C, 15N2 with NaOH gave gemcitabine-13C, 15N2, and its metabolite was obtained by further hydrolytic deamination of gemcitabine-13C, 15N2. The final products were characterized and detected by HPLC, LC-MS and NMR, and confirmed that the chemical purities were higher than 98%, isotopic abundances were 99% 13C, 98% 15N, and they were suitable for drug metabolism studies.

  20. Global ocean climatology of the 13C Suess effect and preindustrial δ13C

    Science.gov (United States)

    Eide, Marie; Olsen, Are; Ninnemann, Ulysses; Eldevik, Tor; Johannessen, Truls

    2017-04-01

    We present the first observationally based estimate of the full global ocean 13C Suess effect since preindustrial times. This was constructed by using Olsen and Ninnemann's [2010] back-calculation method to calculate the 13C Suess effect with data from 29 cruises spanning the world ocean. We find a strong 13C Suess effect in the upper 1000 m of all basins, with strongest decrease in the Subtropical Gyres of the Northern Hemisphere, where δ13C has decreased by more than 0.8‰ since the industrial revolution. At greater depths, a significant 13C Suess effect can only be detected in the northern parts of the North Atlantic Ocean. The magnitude of the 13C Suess effect is correlated with the concentration of anthropogenic carbon, but their relationship varying strongly between water masses, reflecting the degree to which source waters are equilibrated with the atmospheric 13C Suess effect before sinking. From the 13C Suess effect estimates, we have estimated the preindustrial δ13C (δ13CPI) along the 29 sections. Further, we developed regional multilinear regression equations, which were applied on the World Ocean Atlas data to construct the δ13CPI climatology, which reveals the natural δ13C distribution in the global ocean. Compared to the modern distribution, the preindustrial δ13C spans a larger range of values, and we find that in some regions in the high northern latitudes, the gradient in modern ocean δ13C is completely reversed compared to the preindustrial. Maximum δ13CPI, of up to 1.8‰, are found in the subtropical gyres of all basins, in the upper and intermediate waters of the North Atlantic, as well as in mode waters with a Southern Ocean origin. Particularly strong gradients occur at intermediate depths, revealing a strong potential for using δ13C as a tracer for changes in water mass geometry at these levels. Further, we identify a much tighter relationship between δ13C and Apparent Oxygen Utilization (AOU) than between δ13C and phosphate that

  1. 1H to 13C Energy Transfer in Solid State NMR Spectroscopy of Natural Organic Systems

    Science.gov (United States)

    Berns, Anne E.; Conte, Pellegrino

    2010-05-01

    ., van Lagen, B., Buurman, P. & de Jager, P.A., 1997. Quantitative Aspects of Solid-State 13C-NMR Spectra of Humic Substances from Soils of Volcanic Systems. Geoderma, 80, 327-338. Conte, P., Piccolo, A., van Lagen, B., Buurman, P. & Hemminga, M.A., 2002. Elemental quantitation of natural organic matter by CPMAS C-13 NMR spectroscopy. Solid State Nuclear Magnetic Resonance, 21, 158-170. Conte, P., Spaccini, R. & Piccolo, A., 2004. State of the art of CPMAS C-13-NMR spectroscopy applied to natural organic matter. Progress in Nuclear Magnetic Resonance Spectroscopy, 44, 215-223. Dria, K.J., Sachleben, J.R. & Hatcher, P.G., 2002. Solid-state carbon-13 nuclear magnetic resonance of humic acids at high magnetic field strengths. Journal of Environmental Quality, 31, 393-401. Kiem, R., Knicker, H., Korschens, M. & Kogel-Knabner, I., 2000. Refractory organic carbon in C-depleted arable soils, as studied by C-13 NMR spectroscopy and carbohydrate analysis. Organic Geochemistry, 31, 655-668. Kögel-Knabner, I., 2000. Analytical approaches for characterizing soil organic matter. Organic Geochemistry, 31, 609-625. Mao, J.D., Hu, W.G., Schmidt-Rohr, K., Davies, G., Ghabbour, E.A. & Xing, B., 2000. Quantitative characterization of humic substances by solid-state carbon-13 nuclear magnetic resonance. Soil Science Society of America Journal, 64, 873-884. Metz, G., Ziliox, M. & Smith, S.O., 1996. Towards quantitative CP-MAS NMR. Solid State Nuclear Magnetic Resonance, 7, 155-160. Preston, C.M., 2001. Carbon-13 solid-state NMR of soil organic matter - using the technique effectively. Canadian Journal of Soil Science, 81, 255-270. Smernik, R.J. & Oades, J.M., 2000a. The use of spin counting for determining quantitation in solid state C-13 NMR spectra of natural organic matter 1. Model systems and the effects of paramagnetic impurities. Geoderma, 96, 101-129. Smernik, R.J. & Oades, J.M., 2000b. The use of spin counting for determining quantitation in solid state C-13 NMR spectra of natural

  2. Optical Nuclear Polarization in the Excited State Through Cross-Relaxation and Its Use in the Study of the Carbon-13 Hyperfine Coupling in the Lowest Triplet State of 1-13C-p-Benzoquinone

    NARCIS (Netherlands)

    Lichtenbelt, Jan H.; Fremeijer, Jan G.F.M.; Wiersma, Douwe A.

    1976-01-01

    In this paper the phenomenon of optical nuclear polarization in the excited state through cross-relaxation is described. It is shown that when the populating and depopulating rates of the triplet spin sublevels are known the absolute nuclear polarizations can be calculated and that optical detection

  3. Coupling XRD, EXAFS and 13C NMR to study the effect of the carbon stoichiometry on the local structure of UC1±x

    OpenAIRE

    CARVAJAL NUNEZ URSULA; MARTEL LAURA; PRIEUR DAMIEN; Eloirdi, Rachel; FARNAN Ian; Vitova, Tonya; Somers, Joseph; LOPEZ HONORATO Eddie

    2012-01-01

    A series of uranium carbide samples, prepared by arc melting with a C/U ratio ranging from 0.96 to 1.04, has been studied by X-Ray Diffraction (XRD), 13C Nuclear Magnetic Resonance (NMR) and by Extended X-ray Absorption Fine Structure (EXAFS). XRD determines phase uniqueness and the increase of the lattice parameter versus the carbon content. In contrast, 13C NMR detects the different carbon environments in the lattice and in this study, clearly identifies the presence of discrete peaks for c...

  4. Measurement of carbonyl chemical shifts of excited protein states by relaxation dispersion NMR spectroscopy: comparison between uniformly and selectively {sup 13}C labeled samples

    Energy Technology Data Exchange (ETDEWEB)

    Lundstroem, Patrik; Hansen, D. Flemming; Kay, Lewis E. [University of Toronto, Department of Medical Genetics (Canada)], E-mail: kay@pound.med.utoronto.ca

    2008-09-15

    Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion nuclear magnetic resonance (NMR) spectroscopy has emerged as a powerful method for quantifying chemical shifts of excited protein states. For many applications of the technique that involve the measurement of relaxation rates of carbon magnetization it is necessary to prepare samples with isolated {sup 13}C spins so that experiments do not suffer from magnetization transfer between coupled carbon spins that would otherwise occur during the CPMG pulse train. In the case of {sup 13}CO experiments however the large separation between {sup 13}CO and {sup 13}C{sup {alpha}} chemical shifts offers hope that robust {sup 13}CO dispersion profiles can be recorded on uniformly {sup 13}C labeled samples, leading to the extraction of accurate {sup 13}CO chemical shifts of the invisible, excited state. Here we compare such chemical shifts recorded on samples that are selectively labeled, prepared using [1-{sup 13}C]-pyruvate and NaH{sup 13}CO{sub 3,} or uniformly labeled, generated from {sup 13}C-glucose. Very similar {sup 13}CO chemical shifts are obtained from analysis of CPMG experiments recorded on both samples, and comparison with chemical shifts measured using a second approach establishes that the shifts measured from relaxation dispersion are very accurate.

  5. Analysing Groundwater Using the 13C Isotope

    Science.gov (United States)

    Awad, Sadek

    The stable isotope of the carbon atom (13C) give information about the type of the mineralisation of the groundwater existing during the water seepage and about the recharge conditions of the groundwater. The concentration of the CO2(aq.) dissolved during the infiltration of the water through the soil's layers has an effect on the mineralisation of this water. The type of the photosynthesis's cycle (C-3 or C-4 carbon cycle) can have a very important role to determine the conditions (closed or open system) of the mineralisation of groundwater. The isotope 13C of the dissolved CO2 in water give us a certain information about the origin and the area of pollution of water. The proportion of the biogenic carbon and its percentage in the mineralisation of groundwater is determined by using the isotope 13C.

  6. States of 13C with abnormal radii

    Directory of Open Access Journals (Sweden)

    Demyanova A.S.

    2016-01-01

    Full Text Available Differential cross-sections of the elastic and inelastic 13C + α scattering were measured at E(α = 90 MeV. The root mean-square radii( of 13C nucleus in the states: 8.86 (1/2−, 3.09 (1/2+ and 9.90 (3/2− MeV were determined by the Modified diffraction model (MDM. The radii of the first two levels are enhanced compared to that of the ground state of 13C, confirming the suggestion that the 8.86 MeV state is an analogue of the Hoyle state in 12C and the 3.09 MeV state has a neutron halo. Some indications to the abnormally small size of the 9.90 MeV state were obtained.

  7. Origin of the conformational modulation of the 13C NMR chemical shift of methoxy groups in aromatic natural compounds.

    Science.gov (United States)

    Toušek, Jaromír; Straka, Michal; Sklenář, Vladimír; Marek, Radek

    2013-01-24

    The interpretation of nuclear magnetic resonance (NMR) parameters is essential to understanding experimental observations at the molecular and supramolecular levels and to designing new and more efficient molecular probes. In many aromatic natural compounds, unusual (13)C NMR chemical shifts have been reported for out-of-plane methoxy groups bonded to the aromatic ring (~62 ppm as compared to the typical value of ~56 ppm for an aromatic methoxy group). Here, we analyzed this phenomenon for a series of aromatic natural compounds using Density Functional Theory (DFT) calculations. First, we checked the methodology used to optimize the structure and calculate the NMR chemical shifts in aromatic compounds. The conformational effects of the methoxy group on the (13)C NMR chemical shift then were interpreted by the Natural Bond Orbital (NBO) and Natural Chemical Shift (NCS) approaches, and by excitation analysis of the chemical shifts, breaking down the total nuclear shielding tensor into the contributions from the different occupied orbitals and their magnetic interactions with virtual orbitals. We discovered that the atypical (13)C NMR chemical shifts observed are not directly related to a different conjugation of the lone pair of electrons of the methoxy oxygen with the aromatic ring, as has been suggested. Our analysis indicates that rotation of the methoxy group induces changes in the virtual molecular orbital space, which, in turn, correlate with the predominant part of the contribution of the paramagnetic deshielding connected with the magnetic interactions of the BD(CMet-H)→BD*(CMet-OMet) orbitals, resulting in the experimentally observed deshielding of the (13)C NMR resonance of the out-of-plane methoxy group.

  8. Investigation of biomasses and chars obtained from pyrolysis of different biomasses with solid-state 13C and 23Na nuclear magnetic resonance spectroscopy

    NARCIS (Netherlands)

    Link, S.; Arvelakis, S.; Spliethoff, H.; Waard, de P.; Samoson, A.

    2008-01-01

    A number of biomass samples (reed, pine pellets, Douglas fir wood chips, wheat straw, peach stones, and olive residue), pretreated biomass samples (leached wheat straw, leached peach stones, and leached olive residue), as well as their chars obtained by pyrolysis using different heating rates (5, 10

  9. Potential traceable markers of organic matter in organic and conventional dairy manure using ultraviolet–visible and solid-state 13C nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Organic dairy (OD) production is drawing increasing attention because of public concerns about food safety, animal welfare and the potential environmental impacts of conventional dairy (CD) systems. However, very limited information is available on how organic farming practices affect the chemical ...

  10. Neutron Diffraction Studies of Nuclear Magnetic Ordering in Copper

    DEFF Research Database (Denmark)

    Jyrkkiö, T.A.; Huiku, M.T.; Siemensmeyer, K.;

    1989-01-01

    to depend strongly on the external magnetic field between zero and the critical fieldB c=0.25 mT, indicating the existence of at least two antiferromagnetic phases. The results are compared to previous measurements of the magnetic susceptibility. Theoretical calculations do not provide a full explanation......We have constructed a two-stage nuclear demagnetization cryostat for neutron diffraction studies of nuclear magnetism in copper. The cryostat is combined with a two-axis neutron spectrometer which can use both polarized and unpolarized neutrons. By demagnetizing highly polarized copper nuclear...

  11. Nuclear Composition of Magnetized GRB Jets

    CERN Document Server

    Shibata, Sanshiro

    2015-01-01

    We investigate the fraction of metal nuclei in the relativistic jets of gamma-ray bursts associated with core-collapse supernovae. We simulate the fallback in jet-induced explosions with two-dimensional relativistic hydrodynamics calculations and the jet acceleration with steady, radial, relativistic magnetohydrodynamics calculations, and derive detail nuclear composition of the jet by postprocessing calculation. We found that if the temperature at the jet launch site is above $4.7\\times 10^9$K, quasi-statistical equilibrium (QSE) is established and heavy nuclei are dissociated to light particles such as $^4$He during the acceleration of the jets. The criterion for the survival of metal nuclei is written in terms of the isotropic jet luminosity as $L_{\\rm j}^{\\rm iso} \\lesssim 3.9\\times 10^{50}(R_{\\rm i}/10^7{\\rm cm})^2 (1+\\sigma_{\\rm i})~{\\rm erg~s^{-1}}$, where $R_{\\rm i}$ and $\\sigma_{\\rm i}$ are the initial radius of the jets and the initial magnetization parameter, respectively. If the jet is initially d...

  12. NUCLEAR MAGNETIC RESONANCE STUDIES OF URANOCENES

    Energy Technology Data Exchange (ETDEWEB)

    Luke, Wayne D.; Streitwieser, Jr., Andrew

    1979-12-01

    In the past several years a substantial amount of work has been devoted toward evaluation of the contact and pseudocontact contributions to the observed isotropic shifts in H nuclear magnetic resonance (NMR) spectra of uranium(IV) organometallic compounds. One reason for interest in this area arises from using the presence of contact shifts as a prcbe for covalent character in the uranium carbon bonds in these compounds. Several extensive {sup 1}H NNR studies on Cp{sub 3} U-X compounds and less extensive studies on uranocenes have been reported. Interpretation of these results suggests that contact shifts-contribute significantly to the observed isotropic shifts. Their presence has been taken as indicative of covalent character of metal carbon bonds in these systems, but agreement is not complete. In this paper we shall review critically the work reported on uranocenes in the light of recent results and report recent work on attempted separation of the observed isotropic shifts in alkyluranocenes into contact and pseudocontact components.

  13. Hyperpolarized 13C Metabolic MRI of the Human Heart: Initial Experience.

    Science.gov (United States)

    Cunningham, Charles H; Lau, Justin Y C; Chen, Albert P; Geraghty, Benjamin J; Perks, William J; Roifman, Idan; Wright, Graham A; Connelly, Kim A

    2016-11-11

    Altered cardiac energetics is known to play an important role in the progression toward heart failure. A noninvasive method for imaging metabolic markers that could be used in longitudinal studies would be useful for understanding therapeutic approaches that target metabolism. To demonstrate the first hyperpolarized (13)C metabolic magnetic resonance imaging of the human heart. Four healthy subjects underwent conventional proton cardiac magnetic resonance imaging followed by (13)C imaging and spectroscopic acquisition immediately after intravenous administration of a 0.1 mmol/kg dose of hyperpolarized [1-(13)C]pyruvate. All subjects tolerated the procedure well with no adverse effects reported ≤1 month post procedure. The [1-(13)C]pyruvate signal appeared within the chambers but not within the muscle. Imaging of the downstream metabolites showed (13)C-bicarbonate signal mainly confined to the left ventricular myocardium, whereas the [1-(13)C]lactate signal appeared both within the chambers and in the myocardium. The mean (13)C image signal:noise ratio was 115 for [1-(13)C]pyruvate, 56 for (13)C-bicarbonate, and 53 for [1-(13)C]lactate. These results represent the first (13)C images of the human heart. The appearance of (13)C-bicarbonate signal after administration of hyperpolarized [1-(13)C]pyruvate was readily detected in this healthy cohort (n=4). This shows that assessment of pyruvate metabolism in vivo in humans is feasible using current technology. URL: https://www.clinicaltrials.gov. Unique identifier: NCT02648009. © 2016 The Authors.

  14. Nuclear magnetic resonance data of C9H11ITe

    Science.gov (United States)

    Mikhova, B. M.

    This document is part of Part 6 `Organic Metalloid Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

  15. Nuclear magnetic resonance data of C10H13ITe

    Science.gov (United States)

    Mikhova, B. M.

    This document is part of Part 6 `Organic Metalloid Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

  16. Nuclear magnetic resonance spectroscopy and chemometrics to identify pine nuts that cause taste disturbance.

    Science.gov (United States)

    Kobler, Helmut; Monakhova, Yulia B; Kuballa, Thomas; Tschiersch, Christopher; Vancutsem, Jeroen; Thielert, Gerhard; Mohring, Arne; Lachenmeier, Dirk W

    2011-07-13

    Nontargeted 400 MHz (13)C and (1)H nuclear magnetic resonance (NMR) spectroscopy was used in the context of food surveillance to reveal Pinus species whose nuts cause taste disturbance following their consumption, the so-called pine nut syndrome (PNS). Using principal component analysis, three groups of pine nuts were distinguished. PNS-causing products were found in only one of the groups, which however also included some normal products. Sensory analysis was still required to confirm PNS, but NMR allowed the sorting of 53% of 57 samples, which belong to the two groups not containing PNS species. Furthermore, soft independent modeling of class analogy was able to classify the samples between the three groups. NMR spectroscopy was judged as suitable for the screening of pine nuts for PNS. This process may be advantageous as a means of importation control that will allow the identification of samples suitable for direct clearance and those that require further sensory analysis.

  17. Implementation of Quantum Logic Gates by Nuclear Magnetic Resonance Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    DU Jiang-Feng; WU Ji-Hui; SHI Ming-Jun; HAN Liang; ZHOU Xian-Yi; YE Bang-Jiao; WENG Hui-Ming; HAN Rong-Dian

    2000-01-01

    Using nuclear magnetic resonance techniques with a solution of cytosine molecules, we show an implementation of certain quantum logic gates (including NOT gate, square-root of NOT gate and controlled-NOT gate), which have central importance in quantum computing. In addition, experimental results show that nuclear magnetic resonance spectroscopy can efficiently measure the result of quantum computing without attendant wave-function collapse.

  18. (1)H, (13)C and (15)N resonance assignment of the first N-terminal RNA recognition motif (RRM) of the human heterogeneous nuclear ribonucleoprotein H (hnRNP H).

    Science.gov (United States)

    Cabal, Stéphanie; van Heijenoort, Carine; Guittet, Eric

    2007-12-01

    Human heterogeneous nuclear ribonucleoprotein H (hnRNP H) regulates alternative splicing of HIV-1 Tat pre-mRNA. The structure of the first N-terminal domain (residues 1-104) of hnRNP H was solved and its binding to an exonic splicing silencer (pESS2) studied. For this, all backbone and 85% of side-chain resonance frequencies were assigned.

  19. Comparison of nuclear electric resonance and nuclear magnetic resonance in integer and fractional quantum Hall states

    Directory of Open Access Journals (Sweden)

    Toru Tomimatsu

    2015-08-01

    Full Text Available Electric-field-induced nuclear resonance (NER: nuclear electric resonance involving quantum Hall states (QHSs was studied at various filling factors by exploiting changes in nuclear spins polarized at quantum Hall breakdown. Distinct from the magnetic dipole interaction in nuclear magnetic resonance, the interaction of the electric-field gradient with the electric quadrupole moment plays the dominant role in the NER mechanism. The magnitude of the NER signal strongly depends on whether electronic states are localized or extended. This indicates that NER is sensitive to the screening capability of the electric field associated with QHSs.

  20. Dynamic nuclear polarization and nuclear magnetic resonance in the simplest pseudospin quantum Hall ferromagnet

    Science.gov (United States)

    Liu, H. W.; Yang, K. F.; Mishima, T. D.; Santos, M. B.; Hirayama, Y.

    2010-12-01

    We present dynamic nuclear polarization (DNP) in the simplest pseudospin quantum Hall ferromagnet (QHF) of an InSb two-dimensional electron gas with a large g factor using tilted magnetic fields. The DNP-induced amplitude change in a resistance spike of the QHF at large current enables observation of the resistively detected nuclear magnetic resonance of the high nuclear spin isotope I115n with nine quadrupole splittings. Our results demonstrate the importance of domain structures in the DNP process. The nuclear spin relaxation time T1 in this QHF was relatively short (˜120s) and almost temperature independent.

  1. Spectroscopy of exotic states of 13C

    Directory of Open Access Journals (Sweden)

    Demyanova A.S.

    2014-03-01

    Full Text Available The differential cross-sections of the elastic and inelastic 13C + α scattering were measured at E(α = 65 MeV. The radii of the states: 8.86 (1/2−, 3.09 (1/2+ and 9.90 (3/2− MeV were determined by the Modified diffraction model (MDM. The radii of the first two levels are enhanced relatively that of the ground state of 13C, confirming the suggestion that the 8.86 MeV state could be an analogue of the Hoyle state in 12C and the 3.09 MeV state has a neutron halo. No enhancement of the radius of the 9.90 MeV state was observed.

  2. Nuclear magnetization in gallium arsenide quantum dots at zero magnetic field.

    Science.gov (United States)

    Sallen, G; Kunz, S; Amand, T; Bouet, L; Kuroda, T; Mano, T; Paget, D; Krebs, O; Marie, X; Sakoda, K; Urbaszek, B

    2014-01-01

    Optical and electrical control of the nuclear spin system allows enhancing the sensitivity of NMR applications and spin-based information storage and processing. Dynamic nuclear polarization in semiconductors is commonly achieved in the presence of a stabilizing external magnetic field. Here we report efficient optical pumping of nuclear spins at zero magnetic field in strain-free GaAs quantum dots. The strong interaction of a single, optically injected electron spin with the nuclear spins acts as a stabilizing, effective magnetic field (Knight field) on the nuclei. We optically tune the Knight field amplitude and direction. In combination with a small transverse magnetic field, we are able to control the longitudinal and transverse components of the nuclear spin polarization in the absence of lattice strain--that is, in dots with strongly reduced static nuclear quadrupole effects, as reproduced by our model calculations.

  3. Nuclear magnetization in gallium arsenide quantum dots at zero magnetic field

    Science.gov (United States)

    Sallen, G.; Kunz, S.; Amand, T.; Bouet, L.; Kuroda, T.; Mano, T.; Paget, D.; Krebs, O.; Marie, X.; Sakoda, K.; Urbaszek, B.

    2014-02-01

    Optical and electrical control of the nuclear spin system allows enhancing the sensitivity of NMR applications and spin-based information storage and processing. Dynamic nuclear polarization in semiconductors is commonly achieved in the presence of a stabilizing external magnetic field. Here we report efficient optical pumping of nuclear spins at zero magnetic field in strain-free GaAs quantum dots. The strong interaction of a single, optically injected electron spin with the nuclear spins acts as a stabilizing, effective magnetic field (Knight field) on the nuclei. We optically tune the Knight field amplitude and direction. In combination with a small transverse magnetic field, we are able to control the longitudinal and transverse components of the nuclear spin polarization in the absence of lattice strain—that is, in dots with strongly reduced static nuclear quadrupole effects, as reproduced by our model calculations.

  4. Robust hyperpolarized (13)C metabolic imaging with selective non-excitation of pyruvate (SNEP).

    Science.gov (United States)

    Chen, Way Cherng; Teo, Xing Qi; Lee, Man Ying; Radda, George K; Lee, Philip

    2015-08-01

    In vivo metabolic imaging using hyperpolarized [1-(13)C]pyruvate provides localized biochemical information and is particularly useful in detecting early disease changes, as well as monitoring disease progression and treatment response. However, a major limitation of hyperpolarized magnetization is its unrecoverable decay, due not only to T1 relaxation but also to radio-frequency (RF) excitation. RF excitation schemes used in metabolic imaging must therefore be able to utilize available hyperpolarized magnetization efficiently and robustly for the optimal detection of substrate and metabolite activities. In this work, a novel RF excitation scheme called selective non-excitation of pyruvate (SNEP) is presented. This excitation scheme involves the use of a spectral selective RF pulse to specifically exclude the excitation of [1-(13)C]pyruvate, while uniformly exciting the key metabolites of interest (namely [1-(13)C]lactate and [1-(13)C]alanine) and [1-(13)C]pyruvate-hydrate. By eliminating the loss of hyperpolarized [1-(13)C]pyruvate magnetization due to RF excitation, the signal from downstream metabolite pools is increased together with enhanced dynamic range. Simulation results, together with phantom measurements and in vivo experiments, demonstrated the improvement in signal-to-noise ratio (SNR) and the extension of the lifetime of the [1-(13)C]lactate and [1-(13)C]alanine pools when compared with conventional non-spectral selective (NS) excitation. SNEP has also been shown to perform comparably well with multi-band (MB) excitation, yet SNEP possesses distinct advantages, including ease of implementation, less stringent demands on gradient performance, increased robustness to frequency drifts and B0 inhomogeneity as well as easier quantification involving the use of [1-(13)C]pyruvate-hydrate as a proxy for the actual [1-(13)C] pyruvate signal. SNEP is therefore a promising alternative for robust hyperpolarized [1-(13)C]pyruvate metabolic imaging with high

  5. Pulse Design in Solid-State Nuclear Magnetic Resonance

    DEFF Research Database (Denmark)

    Palani, Ravi Shankar

    2017-01-01

    The work presented in this dissertation is centred on the theory of experimental methods in solid-state Nuclear Magnetic Resonance (NMR) spectroscopy, which deals with interaction of electromagnetic radiation with nuclei in a magnetic field and possessing a fundamental quantum mechanical property...

  6. Nuclear magnetic resonance in environmental engineering: principles and applications.

    NARCIS (Netherlands)

    Lens, P.N.L.; Hemminga, M.A.

    1998-01-01

    This paper gives an introduction to nuclear magnetic resonance spectroscopy (NMR) and magnetic resonance imaging (MRI) in relation to applications in the field of environmental science and engineering. The underlying principles of high resolution solution and solid state NMR, relaxation time measure

  7. Production of Specifically Labeled Compounds by Methanobacterium espanolae Grown on H2-CO2 plus [13C]Acetate †

    OpenAIRE

    Patel, Girishchandra B; Sprott, Dennis; Ekiel, Irena

    1993-01-01

    Methanobacterium espanolae, an acidiphilic methanogen, required acetate for maximal growth on H2-CO2. In the presence of 5 to 15 mM acetate, at a growth pH of 5.5, the μmax was 0.05 h-1. M. espanolae consumed 12.3 mM acetate during 96 h of incubation at 35°C with shaking at 100 rpm. At initial acetate levels of 2.5 to 10.0 mM, the amount of biomass produced was dependent on the amount of acetate in the medium. 13C nuclear magnetic resonance spectra of protein hydrolysates obtained from cultur...

  8. Electron transport through nuclear pasta in magnetized neutron stars

    CERN Document Server

    Yakovlev, D G

    2015-01-01

    We present a simple model for electron transport in a possible layer of exotic nuclear clusters (in the so called nuclear pasta layer) between the crust and liquid core of a strongly magnetized neutron star. The electron transport there can be strongly anisotropic and gyrotropic. The anisotropy is produced by different electron effective collision frequencies along and across local symmetry axis in domains of exotic ordered nuclear clusters and by complicated effects of the magnetic field. We also calculate averaged kinetic coefficients in case local domains are freely oriented. Possible applications of the obtained results and open problems are outlined.

  9. Hepatic UDP-glucose 13C isotopomers from [U-13C]glucose: a simple analysis by 13C NMR of urinary menthol glucuronide.

    Science.gov (United States)

    Mendes, Ana C; Caldeira, M Madalena; Silva, Claudia; Burgess, Shawn C; Merritt, Matthew E; Gomes, Filipe; Barosa, Cristina; Delgado, Teresa C; Franco, Fatima; Monteiro, Pedro; Providencia, Luis; Jones, John G

    2006-11-01

    Menthol glucuronide was isolated from the urine of a healthy 70-kg female subject following ingestion of 400 mg of peppermint oil and 6 g of 99% [U-(13)C]glucose. Glucuronide (13)C-excess enrichment levels were 4-6% and thus provided high signal-to-noise ratios (SNRs) for confident assignment of (13)C-(13)C spin-coupled multiplet components within each (13)C resonance by (13)C NMR. The [U-(13)C]glucuronide isotopomer derived via direct pathway conversion of [U-(13)C]glucose to [U-(13)C]UDP-glucose was resolved from [1,2,3-(13)C(3)]- and [1,2-(13)C(2)]glucuronide isotopomers derived via Cori cycle or indirect pathway metabolism of [U-(13)C]glucose. In a second study, a group of four overnight-fasted patients (63 +/- 10 kg) with severe heart failure were given peppermint oil and infused with [U-(13)C]glucose for 4 hr (14 mg/kg prime, 0.12 mg/kg/min constant infusion) resulting in a steady-state plasma [U-(13)C]glucose enrichment of 4.6% +/- 0.6%. Menthol glucuronide was harvested and glucuronide (13)C-isotopomers were analyzed by (13)C NMR. [U-(13)C]glucuronide enrichment was 0.6% +/- 0.1%, and the sum of [1,2,3-(13)C(3)] and [1,2-(13)C(2)]glucuronide enrichments was 0.9% +/- 0.2%. From these data, flux of plasma glucose to hepatic UDPG was estimated to be 15% +/- 4% that of endogenous glucose production (EGP), and the Cori cycle accounted for at least 32% +/- 10% of GP. (c) 2006 Wiley-Liss, Inc.

  10. Parahydrogen enhanced zero-field nuclear magnetic resonance

    OpenAIRE

    Theis, Thomas; Ganssle, Paul; Kervern, Gwendal; Knappe, Svenja; Kitching, John; Ledbetter, Micah; Budker, Dmitry; Pines, Alex

    2011-01-01

    Nuclear magnetic resonance (NMR), conventionally detected in multi-tesla magnetic fields, is a powerful analytical tool for the determination of molecular identity, structure, and function. With the advent of prepolarization methods and alternative detection schemes using atomic magnetometers or superconducting quantum interference devices (SQUIDs), NMR in very low- (~earth's field), and even zero-field, has recently attracted considerable attention. Despite the use of SQUIDs or atomic magnet...

  11. Accurate determinations of one-bond 13C-13C couplings in 13C-labeled carbohydrates

    Science.gov (United States)

    Azurmendi, Hugo F.; Freedberg, Darón I.

    2013-03-01

    Carbon plays a central role in the molecular architecture of carbohydrates, yet the availability of accurate methods for 1DCC determination has not been sufficiently explored, despite the importance that such data could play in structural studies of oligo- and polysaccharides. Existing methods require fitting intensity ratios of cross- to diagonal-peaks as a function of the constant-time (CT) in CT-COSY experiments, while other methods utilize measurement of peak separation. The former strategies suffer from complications due to peak overlap, primarily in regions close to the diagonal, while the latter strategies are negatively impacted by the common occurrence of strong coupling in sugars, which requires a reliable assessment of their influence in the context of RDC determination. We detail a 13C-13C CT-COSY method that combines a variation in the CT processed with diagonal filtering to yield 1JCC and RDCs. The strategy, which relies solely on cross-peak intensity modulation, is inspired in the cross-peak nulling method used for JHH determinations, but adapted and extended to applications where, like in sugars, large one-bond 13C-13C couplings coexist with relatively small long-range couplings. Because diagonal peaks are not utilized, overlap problems are greatly alleviated. Thus, one-bond couplings can be determined from different cross-peaks as either active or passive coupling. This results in increased accuracy when more than one determination is available, and in more opportunities to measure a specific coupling in the presence of severe overlap. In addition, we evaluate the influence of strong couplings on the determination of RDCs by computer simulations. We show that individual scalar couplings are notably affected by the presence of strong couplings but, at least for the simple cases studied, the obtained RDC values for use in structural calculations were not, because the errors introduced by strong couplings for the isotropic and oriented phases are very

  12. Accurate determinations of one-bond 13C-13C couplings in 13C-labeled carbohydrates.

    Science.gov (United States)

    Azurmendi, Hugo F; Freedberg, Darón I

    2013-03-01

    Carbon plays a central role in the molecular architecture of carbohydrates, yet the availability of accurate methods for (1)D(CC) determination has not been sufficiently explored, despite the importance that such data could play in structural studies of oligo- and polysaccharides. Existing methods require fitting intensity ratios of cross- to diagonal-peaks as a function of the constant-time (CT) in CT-COSY experiments, while other methods utilize measurement of peak separation. The former strategies suffer from complications due to peak overlap, primarily in regions close to the diagonal, while the latter strategies are negatively impacted by the common occurrence of strong coupling in sugars, which requires a reliable assessment of their influence in the context of RDC determination. We detail a (13)C-(13)C CT-COSY method that combines a variation in the CT processed with diagonal filtering to yield (1)J(CC) and RDCs. The strategy, which relies solely on cross-peak intensity modulation, is inspired in the cross-peak nulling method used for J(HH) determinations, but adapted and extended to applications where, like in sugars, large one-bond (13)C-(13)C couplings coexist with relatively small long-range couplings. Because diagonal peaks are not utilized, overlap problems are greatly alleviated. Thus, one-bond couplings can be determined from different cross-peaks as either active or passive coupling. This results in increased accuracy when more than one determination is available, and in more opportunities to measure a specific coupling in the presence of severe overlap. In addition, we evaluate the influence of strong couplings on the determination of RDCs by computer simulations. We show that individual scalar couplings are notably affected by the presence of strong couplings but, at least for the simple cases studied, the obtained RDC values for use in structural calculations were not, because the errors introduced by strong couplings for the isotropic and

  13. A novel method for coil efficiency estimation: Validation with a 13C birdcage

    DEFF Research Database (Denmark)

    Giovannetti, Giulio; Frijia, Francesca; Hartwig, Valentina;

    2012-01-01

    -to-noise ratio. In this work, we propose a novel method for RF coil efficiency estimation based on the use of a perturbing loop. The proposed method consists of loading the coil with a known resistor by inductive coupling and measuring the quality factor with and without the load. We tested the method...... by measuring the efficiency of a 13C birdcage coil tuned at 32.13 MHz and verified its accuracy by comparing the results with the nuclear magnetic resonance nutation experiment. The method allows coil performance characterization in a short time and with great accuracy, and it can be used both on the bench...... and inside the scanner. (c) 2012 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 41B: 139143, 2012...

  14. Coil Sensitivity Estimation with Perturbing Sphere Method: Application to 13C Birdcages

    DEFF Research Database (Denmark)

    Giovannetti, G.; Frijia, F.; Menichetti, L.;

    2012-01-01

    Radiofrequency coils in magnetic resonance systems are used to irradiate nuclear spins and to pick up the signals emitted by the nuclei with high signal-to-noise ratio and large sensitivity region. The quality of the obtained images strongly depends upon the coil performance. When used at low...... frequencies, a number of drawbacks arise that drastically reduce their overall performances. In this work, we describe and verify the accuracy of a coil sensitivity estimation method based on the perturbing sphere theory which permits characterization of coil performance in a short time and that can be useful...... for periodical coil quality controls. In particular, we describe the application of the method by testing two 13C birdcage coils tuned at 32.13 MHz and verifying its accuracy using theoretical and experimental approaches....

  15. The Fourier Transform in Chemistry. Part 1. Nuclear Magnetic Resonance: Introduction.

    Science.gov (United States)

    King, Roy W.; Williams, Kathryn R.

    1989-01-01

    Using fourier transformation methods in nuclear magnetic resonance has made possible increased sensitivity in chemical analysis. This article describes these methods as they relate to magnetization, the RF magnetic field, nuclear relaxation, the RF pulse, and free induction decay. (CW)

  16. (13)C MRS of human brain at 7 Tesla using [2-(13)C]glucose infusion and low power broadband stochastic proton decoupling.

    Science.gov (United States)

    Li, Shizhe; An, Li; Yu, Shao; Ferraris Araneta, Maria; Johnson, Christopher S; Wang, Shumin; Shen, Jun

    2016-03-01

    Carbon-13 ((13)C) MR spectroscopy (MRS) of the human brain at 7 Tesla (T) may pose patient safety issues due to high radiofrequency (RF) power deposition for proton decoupling. The purpose of present work is to study the feasibility of in vivo (13)C MRS of human brain at 7 T using broadband low RF power proton decoupling. Carboxylic/amide (13)C MRS of human brain by broadband stochastic proton decoupling was demonstrated on a 7 T scanner. RF safety was evaluated using the finite-difference time-domain method. (13)C signal enhancement by nuclear Overhauser effect (NOE) and proton decoupling was evaluated in both phantoms and in vivo. At 7 T, the peak amplitude of carboxylic/amide (13)C signals was increased by a factor of greater than 4 due to the combined effects of NOE and proton decoupling. The 7 T (13)C MRS technique used decoupling power and average transmit power of less than 35 watts (W) and 3.6 W, respectively. In vivo (13)C MRS studies of human brain can be performed at 7 T, well below the RF safety threshold, by detecting carboxylic/amide carbons with broadband stochastic proton decoupling. © 2015 Wiley Periodicals, Inc.

  17. Coherent control of a {sup 13}C NV{sup -} center

    Energy Technology Data Exchange (ETDEWEB)

    Scharfenberger, Burkhard; Nemoto, Kae [National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430 (Japan); Munro, William J. [NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan)

    2013-07-01

    We investigate the theoretically achievable fidelity for coherently controlling an effective three qubit system consisting of a negatively charged NV center in diamond coupling via an hyperfine interaction to one nearby {sup 13}C nuclear spin using only micro- and radio wave pulses. With its long coherence times and comparatively simple optical accessibility, already the 'bare' NV{sup -} center has an interesting potential in quantum computing related applications. Although a number of experiments have already been conducted using NV centers with one or more {sup 13}C nearby, fidelity achieved are limited not only by experimental inaccuracies but a lack of theoretical understanding of the system dynamics. We seek to redress this by fully modelling the NVC systems behaviour in the ground state manifold, including all hyperfine interactions (between N and V as well as C and V) and dissipation where parameters are taken from previous experimental work as well as theoretical ab-initio studies. We show that for close-by carbons, the strong hyperfine interaction leads to unwanted mixing of levels which ultimately limits fidelity in single-qubit driving and entanglement generation to less than 99% in the experimentally interesting weak magnetic fields regime.

  18. Kinetic analysis of glycogen turnover: relevance to human brain 13C-NMR spectroscopy.

    Science.gov (United States)

    DiNuzzo, Mauro

    2013-10-01

    A biophysical model of the glycogen molecule is developed, which takes into account the points of attack of synthase and phosphorylase at the level of the individual glucose chain. Under the sole assumption of steric effects governing enzyme accessibility to glucosyl residues, the model reproduces the known equilibrium structure of cellular glycogen at steady state. In particular, experimental data are reproduced assuming that synthase (1) operates preferentially on inner chains of the molecule and (2) exhibits a faster mobility than phosphorylase in translocating from an attacked chain to another. The model is then used to examine the turnover of outer versus inner tiers during the labeling process of isotopic enrichment (IE) experiments. Simulated data are fitted to in vivo (13)C nuclear magnetic resonance spectroscopy measurements obtained in the human brain under resting conditions. Within this experimental set-up, analysis of simulated label incorporation and retention shows that 7% to 35% of labeled glucose is lost from the rapidly turning-over surface of the glycogen molecule when stimulation onset is delayed by 7 to 11.5 hours after the end of [1-(13)C]glucose infusion as done in actual procedures. The substantial label washout before stimulation suggests that much of the subsequent activation-induced glycogenolysis could remain undetected. Overall, these results show that the molecular structure significantly affects the patterns of synthesis and degradation of glycogen, which is relevant for appropriate design of labeling experiments aiming at investigating the functional roles of this glucose reserve.

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

    Science.gov (United States)

    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.

  20. Capacitor-based detection of nuclear magnetization: nuclear quadrupole resonance of surfaces.

    Science.gov (United States)

    Gregorovič, Alan; Apih, Tomaž; Kvasić, Ivan; Lužnik, Janko; Pirnat, Janez; Trontelj, Zvonko; Strle, Drago; Muševič, Igor

    2011-03-01

    We demonstrate excitation and detection of nuclear magnetization in a nuclear quadrupole resonance (NQR) experiment with a parallel plate capacitor, where the sample is located between the two capacitor plates and not in a coil as usually. While the sensitivity of this capacitor-based detection is found lower compared to an optimal coil-based detection of the same amount of sample, it becomes comparable in the case of very thin samples and even advantageous in the proximity of conducting bodies. This capacitor-based setup may find its application in acquisition of NQR signals from the surface layers on conducting bodies or in a portable tightly integrated nuclear magnetic resonance sensor.

  1. Optoacoustic 13C-breath test analyzer

    Science.gov (United States)

    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.

  2. Noninvasive measurement of brain glycogen by nuclear magnetic resonance spectroscopy and its application to the study of brain metabolism.

    Science.gov (United States)

    Tesfaye, Nolawit; Seaquist, Elizabeth R; Oz, Gülin

    2011-12-01

    Glycogen is the reservoir for glucose in the brain. Beyond the general agreement that glycogen serves as an energy source in the central nervous system, its exact role in brain energy metabolism has yet to be elucidated. Experiments performed in cell and tissue culture and animals have shown that glycogen content is affected by several factors, including glucose, insulin, neurotransmitters, and neuronal activation. The study of in vivo glycogen metabolism has been hindered by the inability to measure glycogen noninvasively, but, in the past several years, the development of a noninvasive localized (13) C nuclear magnetic resonance (NMR) spectroscopy method has allowed the study of glycogen metabolism in the conscious human. With this technique, (13) C-glucose is administered intravenously, and its incorporation into and washout from brain glycogen is tracked. One application of this method has been to the study of brain glycogen metabolism in humans during hypoglycemia: data have shown that mobilization of brain glycogen is augmented during hypoglycemia, and, after a single episode of hypoglycemia, glycogen synthesis rate is increased, suggesting that glycogen stores rebound to levels greater than baseline. Such studies suggest that glycogen may serve as a potential energy reservoir in hypoglycemia and may participate in the brain's adaptation to recurrent hypoglycemia and eventual development of hypoglycemia unawareness. Beyond this focused area of study, (13) C NMR spectroscopy has a broad potential for application in the study of brain glycogen metabolism and carries the promise of a better understanding of the role of brain glycogen in diabetes and other conditions.

  3. Magnet Design Considerations for Fusion Nuclear Science Facility

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Y. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Kessel, C. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); El-Guebaly, L. [Univ. of Wisconsin, Madison, WI (United States) Fusion Technology Institute; Titus, P. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

    2016-06-01

    The Fusion Nuclear Science Facility (FNSF) is a nuclear confinement facility that provides a fusion environment with components of the reactor integrated together to bridge the technical gaps of burning plasma and nuclear science between the International Thermonuclear Experimental Reactor (ITER) and the demonstration power plant (DEMO). Compared with ITER, the FNSF is smaller in size but generates much higher magnetic field, i.e., 30 times higher neutron fluence with three orders of magnitude longer plasma operation at higher operating temperatures for structures surrounding the plasma. Input parameters to the magnet design from system code analysis include magnetic field of 7.5 T at the plasma center with a plasma major radius of 4.8 m and a minor radius of 1.2 m and a peak field of 15.5 T on the toroidal field (TF) coils for the FNSF. Both low-temperature superconductors (LTS) and high-temperature superconductors (HTS) are considered for the FNSF magnet design based on the state-of-the-art fusion magnet technology. The higher magnetic field can be achieved by using the high-performance ternary restacked-rod process Nb3Sn strands for TF magnets. The circular cable-in-conduit conductor (CICC) design similar to ITER magnets and a high-aspect-ratio rectangular CICC design are evaluated for FNSF magnets, but low-activation-jacket materials may need to be selected. The conductor design concept and TF coil winding pack composition and dimension based on the horizontal maintenance schemes are discussed. Neutron radiation limits for the LTS and HTS superconductors and electrical insulation materials are also reviewed based on the available materials previously tested. The material radiation limits for FNSF magnets are defined as part of the conceptual design studies for FNSF magnets.

  4. Oxidative stress-induced metabolic changes in mouse C2C12 myotubes studied with high-resolution 13C, 1H, and 31P NMR spectroscopy.

    Science.gov (United States)

    Straadt, Ida K; Young, Jette F; Petersen, Bent O; Duus, Jens Ø; Gregersen, Niels; Bross, Peter; Oksbjerg, Niels; Theil, Peter K; Bertram, Hanne C

    2010-02-10

    In this study, stress in relation to slaughter was investigated in a model system by the use of (13)C, (1)H, and (31)P nuclear magnetic resonance (NMR) spectroscopy for elucidating changes in the metabolites in C2C12 myotubes exposed to H(2)O(2)-induced stress. Oxidative stress resulted in lower levels of several metabolites, mainly amino acids; however, higher levels of alanine were apparent in the (13)C spectra after incubation with [(13)C(1)]glucose. In the (13)C spectra [(13)C(3)]lactate tended to increase after exposure to increasing concentrations of H(2)O(2); conversely, a tendency to lower levels of the unlabeled ((12)C) lactate were identified in the (1)H spectra after stress exposure. These data indicate an increase in de novo synthesis of alanine, concomitant with a release of lactate from the myotubes to the medium at oxidative stress conditions. The changes in the metabolite levels could possibly be useful as markers for meat quality traits.

  5. Solid-State 13C NMR Spectroscopy Applied to the Study of Carbon Blacks and Carbon Deposits Obtained by Plasma Pyrolysis of Natural Gas

    Directory of Open Access Journals (Sweden)

    Jair C. C. Freitas

    2016-01-01

    Full Text Available Solid-state 13C nuclear magnetic resonance (NMR spectroscopy was used in this work to analyze the physical and chemical properties of plasma blacks and carbon deposits produced by thermal cracking of natural gas using different types of plasma reactors. In a typical configuration with a double-chamber reactor, N2 or Ar was injected as plasma working gas in the first chamber and natural gas was injected in the second chamber, inside the arc column. The solid residue was collected at different points throughout the plasma apparatus and analyzed by 13C solid-state NMR spectroscopy, using either cross polarization (CP or direct polarization (DP, combined with magic angle spinning (MAS. The 13C CP/MAS NMR spectra of a number of plasma blacks produced in the N2 plasma reactor showed two resonance bands, broadly identified as associated with aromatic and aliphatic groups, with indication of the presence of oxygen- and nitrogen-containing groups in the aliphatic region of the spectrum. In contrast to DP experiments, only a small fraction of 13C nuclei in the plasma blacks are effectively cross-polarized from nearby 1H nuclei and are thus observed in spectra recorded with CP. 13C NMR spectra are thus useful to distinguish between different types of carbon species in plasma blacks and allow a selective study of groups spatially close to hydrogen in the material.

  6. Multisite Kinetic Modeling of 13C Metabolic MR Using [1-13C]Pyruvate

    Directory of Open Access Journals (Sweden)

    Pedro A. Gómez Damián

    2014-01-01

    Full Text Available Hyperpolarized 13C imaging allows real-time in vivo measurements of metabolite levels. Quantification of metabolite conversion between [1-13C]pyruvate and downstream metabolites [1-13C]alanine, [1-13C]lactate, and [13C]bicarbonate can be achieved through kinetic modeling. Since pyruvate interacts dynamically and simultaneously with its downstream metabolites, the purpose of this work is the determination of parameter values through a multisite, dynamic model involving possible biochemical pathways present in MR spectroscopy. Kinetic modeling parameters were determined by fitting the multisite model to time-domain dynamic metabolite data. The results for different pyruvate doses were compared with those of different two-site models to evaluate the hypothesis that for identical data the uncertainty of a model and the signal-to-noise ratio determine the sensitivity in detecting small physiological differences in the target metabolism. In comparison to the two-site exchange models, the multisite model yielded metabolic conversion rates with smaller bias and smaller standard deviation, as demonstrated in simulations with different signal-to-noise ratio. Pyruvate dose effects observed previously were confirmed and quantified through metabolic conversion rate values. Parameter interdependency allowed an accurate quantification and can therefore be useful for monitoring metabolic activity in different tissues.

  7. Nuclear Magnetic Resonance Quantum Computing Using Liquid Crystal Solvents

    CERN Document Server

    Yannoni, C S; Vandersypen, L M K; Miller, D C; Kubinec, M G; Chuang, I L; Yannoni, Costantino S.; Sherwood, Mark H.; Vandersypen, Lieven M.K.; Miller, Dolores C.; Kubinec, Mark G.; Chuang, Isaac L.

    1999-01-01

    Liquid crystals offer several advantages as solvents for molecules used for NMR quantum computing (NMRQC). The dipolar coupling between nuclear spins manifest in the NMR spectra of molecules oriented by a liquid crystal permits a significant increase in clock frequency, while short spin-lattice relaxation times permit fast recycling of algorithms, and save time in calibration and signal-enhancement experiments. Furthermore, the use of liquid crystal solvents offers scalability in the form of an expanded library of spin-bearing molecules suitable for NMRQC. These ideas are demonstrated with the successful execution of a 2-qubit Grover search using a molecule ($^{13}$C$^{1}$HCl$_3$) oriented in a liquid crystal and a clock speed eight times greater than in an isotropic solvent. Perhaps more importantly, five times as many logic operations can be executed within the coherence time using the liquid crystal solvent.

  8. Hypermetabolic state in the 7-month-old triple transgenic mouse model of Alzheimer's disease and the effect of lipoic acid: a 13C-NMR study.

    Science.gov (United States)

    Sancheti, Harsh; Patil, Ishan; Kanamori, Keiko; Díaz Brinton, Roberta; Zhang, Wei; Lin, Ai-Ling; Cadenas, Enrique

    2014-11-01

    Alzheimer's disease (AD) is characterized by age-dependent biochemical, metabolic, and physiologic changes. These age-dependent changes ultimately converge to impair cognitive functions. This study was carried out to examine the metabolic changes by probing glucose and tricarboxylic acid cycle metabolism in a 7-month-old triple transgenic mouse model of AD (3xTg-AD). The effect of lipoic acid, an insulin-mimetic agent, was also investigated to examine its ability in modulating age-dependent metabolic changes. Seven-month-old 3xTg-AD mice were given intravenous infusion of [1-(13)C]glucose followed by an ex vivo (13)C nuclear magnetic resonance to determine the concentrations of (13)C-labeled isotopomers of glutamate, glutamine, aspartate, gamma aminobutyric acid, and N-acetylaspartate. An intravenous infusion of [1-(13)C]glucose+[1,2-(13)C]acetate was given for different periods of time to distinguish neuronal and astrocytic metabolism. Enrichments of glutamate, glutamine, and aspartate were calculated after quantifying the total ((12)C+(13)C) concentrations by high-performance liquid chromatography. A hypermetabolic state was clearly evident in 7-month-old 3xTg-AD mice in contrast to the hypometabolic state reported earlier in 13-month-old mice. Hypermetabolism was evidenced by prominent increase of (13)C labeling and enrichment in the 3xTg-AD mice. Lipoic acid feeding to the hypermetabolic 3xTg-AD mice brought the metabolic parameters to the levels of nonTg mice.

  9. Nuclear magnetic resonance in environmental engineering: principles and applications.

    Science.gov (United States)

    Lens, P N; Hemminga, M A

    1998-01-01

    This paper gives an introduction to nuclear magnetic resonance spectroscopy (NMR) and magnetic resonance imaging (MRI) in relation to applications in the field of environmental science and engineering. The underlying principles of high resolution solution and solid state NMR, relaxation time measurements and imaging are presented. Then, the use of NMR is illustrated and reviewed in studies of biodegradation and biotransformation of soluble and solid organic matter, removal of nutrients and xenobiotics, fate of heavy metal ions, and transport processes in bioreactor systems.

  10. Evaluation of nuclear magnetic resonance spectroscopy variability

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, Felipe Rodrigues; Salmon, Carlos Ernesto Garrido, E-mail: garrido@ffclrp.usp.br [Universidade de Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Fac. de Filisofia, Ciencias e Letras; Otaduy, Maria Concepcion Garcia [Universidade de Sao Paulo (FAMUS/USP), Sao Paulo, SP (Brazil). Fac. de Medicina. Departamento de Radiologia

    2014-11-01

    Introduction: the intrinsically high sensitivity of Magnetic Resonance Spectroscopy (MRS) causes considerable variability in metabolite quantification. In this study, we evaluated the variability of MRS in two research centers using the same model of magnetic resonance image scanner. Methods: two metabolic phantoms were created to simulate magnetic resonance spectra from in vivo hippocampus. The phantoms were filled with the same basic solution containing the following metabolites: N-acetyl-aspartate, creatine, choline, glutamate, glutamine and inositol. Spectra were acquired over 15 months on 26 acquisition dates, resulting in a total of 130 spectra per center. Results: the phantoms did not undergo any physical changes during the 15-month period. Temporal analysis from both centers showed mean metabolic variations of 3.7% in acquisitions on the same day and of 8.7% over the 15-month period. Conclusion: The low deviations demonstrated here, combined with the high specificity of Magnetic Resonance Spectroscopy, confirm that it is feasible to use this technique in multicenter studies in neuroscience research. (author)

  11. Tetrapropylammonium Occlusion in Nanoaggregates of Precursor of Silicalite-1 Zeolite Studied by 1H and 13C NMR

    Directory of Open Access Journals (Sweden)

    Mohamed Haouas

    2016-06-01

    Full Text Available The dynamic behavior of tetrapropylammonium (TPA cations in the clear precursor sols for silicalite synthesis has been investigated by 1H diffusion ordered spectroscopy (DOSY, T1, T2, and T1ρ 1H relaxation, as well as 1H→13C cross polarization (CP nuclear magnetic resonance. The DOSY NMR experiments showed the presence of strong solute–solvent interactions in concentrated sols, which are decreasing upon dilution. Similarities in dependence of diffusion coefficients with fractional power of the viscosity constant observed for nanoparticles, TPA cations and water led to the conclusion that they aggregate as anisotropic silicate-TPA particles. Relaxation studies as well as 1H→13C CP experiments provide information on dynamic properties of ethanol, water and TPA cations, which are function of silicate aggregates. The general tendency showed that the presence of silicate as oligomers and particles decreases the relaxation times, in particular T2 and T1ρH, as a consequence of involvement of these latter in ion-pairing interactions with water-solvated TPA molecules slowing down their mobility. Furthermore, from the 1H→13C CP dynamics curve profiles a change in the CP transfer regime was observed from fast (TCH << T1ρH for solutions without silicates to moderate (TCH~T1ρH when silicates are interacting with the TPA cations that may reflect the occlusion of TPA into flexible silicate hydrate aggregates.

  12. High Radiation Environment Nuclear Fragment Separator Magnet

    Energy Technology Data Exchange (ETDEWEB)

    Kahn, Stephen [Muons, Inc., Batavia, IL (United States); Gupta, Ramesh [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-01-31

    Superconducting coils wound with HTS conductor can be used in magnets located in a high radiation environment. NbTi and Nb3Sn superconductors must operate at 4.5 K or below where removal of heat is less efficient. The HTS conductor can carry significant current at higher temperatures where the Carnot efficiency is significantly more favorable and where the coolant heat capacity is much larger. Using the HTS conductor the magnet can be operated at 40 K. This project examines the use of HTS conductor for the Michigan State University Facility For Rare Isotope Beams (FRIB) fragment separator dipole magnet which bends the beam by 30° and is located in a high radiation region that will not be easily accessible. Two of these magnets are needed to select the chosen isotope. There are a number of technical challenges to be addressed in the design of this magnet. The separator dipole is 2 m long and subtends a large angle. The magnet should keep a constant transverse field profile along its beam reference path. Winding coils with a curved inner segment is difficult as the conductor will tend to unwind during the process. In the Phase I project two approaches to winding the conductor were examined. The first was to wind the coils with curved sections on the inner and outer segments with the inner segment wound with negative curvature. The alternate approach was to use a straight segment on the inner segment to avoid negative curvature. In Phase I coils with a limited number of turns were successfully wound and tested at 77 K for both coil configurations. The Phase II program concentrated on the design, coil winding procedures, structural analysis, prototyping and testing of an HTS curved dipole coil at 40 K with a heat load representative of the radiation environment. One of the key criteria of the design of this magnet is to avoid the use of organic materials that would degrade rapidly in radiation. The Lorentz forces expected from the coils interacting with the

  13. Measuring Long-Lived ^{13}C-Singlet State Lifetimes at Natural Abundance

    CERN Document Server

    Claytor, Kevin E; Feng, Yesu; Warren, Warren

    2013-01-01

    Long-lived singlet states hold the potential to drastically extend the lifetime of hyperpolarization in molecular tracers for in-vivo magnetic resonance imaging (MRI). Such long lived hyperpolarization can be used for elucidation of fundamental metabolic pathways, early diagnosis, and optimization of clinical tests for new medication. All previous measurements of 13C singlet state lifetimes rely on costly and time consuming syntheses of 13C labeled compounds. Here we show that it is possible to determine 13C singlet state lifetimes by detecting the naturally abundant doubly-labeled species. This approach allows for rapid and low cost screening of potential molecular biomarkers bearing long-lived singlet states.

  14. Zero-field nuclear magnetic resonance in high field by modulated rf sequences.

    Science.gov (United States)

    Nishiyama, Yusuke; Yamazaki, Toshio

    2007-04-07

    The authors propose a novel approach to design and evaluate sequences for zero-field NMR spectra in high field (ZFHF) by using amplitude and phase modulated rf sequences. ZFHF provide sharp peaks for the dipolar interaction between two nuclear spins even if the orientation of the molecules is distributed. The internuclear distance r can be directly obtained from the peak position which is proportional to r-3. Numerous ZFHF sequences are obtained. A sequence is selected from them by the systematic evaluation of the sequences. The new ZFHF sequence is less affected by chemical shift anisotropy (CSA) than the previous sequences; the sequence can be used for systems with large CSA such as a dipolar coupled 13C-pair system under realistically high field. 13C ZFHF spectra of 13C2 diammonium succinate and 13C2 diammonium oxalate were observed under the 9.4 T field.

  15. DC SQUID Spectrometers for Nuclear Quadrupole and Low-Field Nuclear Magnetic Resonance Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    TonThat, Dinh M. [Univ. of California, Berkeley, CA (United States)

    1998-04-01

    The dc Superconducting Quantum Interference Device (SQUJD) is a very sensitive detector of magnetic flux, with a typical flux noise of the order of 1 μΦ0Hz-1/2 at liquid helium temperature (Φ0=h/2e). This inherent flux sensitivity of the SQUID is used in a spectrometer for the detection of nuclear magnetic resonance (NMR.)and nuclear quadruple resonance (NQR). The processing magnetic field from the nuclear spins is coupled to the SQUID by mean of a flux transformer. The SQUID NMR spectrometer is used to measure the longitudinal relaxation time T1 of solid 129Xe at 4.2 K down to 0.1 mT.

  16. Neutron orbital radii in {sup 13} C; Radios orbitales neutronicos en {sup 13} C

    Energy Technology Data Exchange (ETDEWEB)

    Aguilera R, E.F.; Murillo, G.; Ramirez, J.J.; Avila, O.L. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1988-01-15

    In this work its were carried out experimental measurements of the reaction {sup 12}C(d,p) {sup 13}C at low energy. Preliminary results of a DWBA analysis of the data are presented, and the possibility of using this reaction to obtain the orbital radius of the transferred neutron is investigated. (Author)

  17. Zero-Field Nuclear Magnetic Resonance

    OpenAIRE

    Weitekamp, D.P.; Bielecki, A.; Zax, D.; Zilm, K.; Pines, A.

    1983-01-01

    In polycrystalline samples, NMR "powder spectra" are broad and much structural information is lost as a result of the orientational disorder. In this Letter Fourier-transform NMR in zero magnetic field is described. With no preferred direction in space, all crystallites contribute equivalently and resolved dipolar splittings can be interpreted directly in terms of internuclear distances. This opens the possiblity of molecular structure determination without the need for single crystals or ori...

  18. Zero-field nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Weitekamp, D.P.; Bielecki, A.; Zax, D.; Zilm, K.; Pines, A.

    1983-05-30

    In polycrystalline samples, NMR ''powder spectra'' are broad and much structural information is lost as a result of the orientational disorder. In this Letter Fourier transform NMR in zero magnetic field is described. With no preferred direction in space, all crystallites contribute equivalently and resolved dipolar splittings can be interpreted directly in terms of internuclear distances. This opens the possibility of molecular structure determination without the need for single crystals or oriented samples.

  19. Realization of a Quantum Scheduling Algorithm Using Nuclear Magnetic Resonance

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-Fu; DENG Zhi-Wei; PAN Yan-Na; LU Zhi-Heng

    2004-01-01

    The quantum scheduling algorithm proposed by Grover is generalized to extend its scope of applications. The generalized algorithm proposed here is realized on a nuclear magnetic resonance quantum computer. The experimental results show that the generalized algorithm can work efficiently in the case that Grover's scheduling algorithm is completely invalid, and represent the quantum advantages when qubits replace classical bits.

  20. Nuclear magnetic resonance imaging of water motion in plants

    NARCIS (Netherlands)

    Scheenen, T.W.J.

    2001-01-01

    This Thesis treats one of the new techniques in plant science i.e. nuclear magnetic resonance imaging (NMRi) applied to water motion in plants. It is a challenge, however, to measure this motion in intact plants quantitatively, because plants impose specific problems when studied using

  1. NMR of TMV. Nuclear magnetic resonance of tobacco mosaic virus

    NARCIS (Netherlands)

    Wit, de J.L.

    1978-01-01

    This Thesis describes the application of conventional 13 C and 1 H high resolution Fourier Transform Nuclear Magnetic resonance (HR FT NMR) to Tobacco Mosaic Virus (TMV) and its protein oligo- and polymers and some other largebiological systems. The rod-like (TMV) consists of 2

  2. Neutron studies of nuclear magnetism at ultralow temperature

    DEFF Research Database (Denmark)

    Siemensmeyer, K.; Clausen, K.N.; Lefmann, K.

    1998-01-01

    Nuclear magnetic order in copper and silver has been investigated by neutron diffraction. Antiferromagnetic order is observed in these simple, diamagnetic metals at temperatures below 50 nK and 560 pK, respectively. Both crystallize in the FCC-symmetry which is fully frustrated for nearest...

  3. Using Nuclear Magnetic Resonance Spectroscopy for Measuring Ternary Phase Diagrams

    Science.gov (United States)

    Woodworth, Jennifer K.; Terrance, Jacob C.; Hoffmann, Markus M.

    2006-01-01

    A laboratory experiment is presented for the upper-level undergraduate physical chemistry curriculum in which the ternary phase diagram of water, 1-propanol and n-heptane is measured using proton nuclear magnetic resonance (NMR) spectroscopy. The experiment builds upon basic concepts of NMR spectral analysis, typically taught in the undergraduate…

  4. Nuclear magnetic response imaging of sap flow in plants

    NARCIS (Netherlands)

    Windt, C.W.

    2007-01-01

    This thesis deals with Nuclear Magnetic Resonance (NMR) imaging of long distance transport in plants. Long distance transport in plants is an enigmatic process. The theoretical framework that describes its basic properties has been in place for almost a century, yet at the same time only little is

  5. Nuclear magnetic resonance imaging of water motion in plants

    NARCIS (Netherlands)

    Scheenen, T.W.J.

    2001-01-01

    This Thesis treats one of the new techniques in plant science i.e. nuclear magnetic resonance imaging (NMRi) applied to water motion in plants. It is a challenge, however, to measure this motion in intact plants quantitatively, because plants impose specific problems when studied using NMRi. At high

  6. 13. Nuclear magnetic resonance users meeting. Extended abstracts book

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    This annual meeting, held in Brazil from May 2 - 6, 2011 comprised seventeen lectures, given by invited speakers from Brazil and other countries, about the use of nuclear magnetic resonance for various analytical purposes; results from ninety five research works, most being carried out by scientific groups from various Brazilian R and D institutions, presented as congress panels/posters. A General Assembly meeting of AUREMN, the Brazilian Association of Nuclear Magnetic Resonance Users, also took place during the event. Main topics of the research works presented at this meeting were thus distributed: 54% in analytical chemistry (mainly organic chemistry, both experimental and theoretical works), 18% in applied life sciences (agricultural and food sciences, biological sciences and medicine), 15% in materials science (including nanostructures, petroleum and alternative fuels), 10% in mathematical methods and computing for the interpretation of NMR data, and the remaining 3% in improvements in instrumentation interfaces or magnetic field configurations.

  7. hNCOcanH pulse sequence and a robust protocol for rapid and unambiguous assignment of backbone ((1)H(N), (15)N and (13)C') resonances in (15)N/(13)C-labeled proteins.

    Science.gov (United States)

    Kumar, Dinesh; Hosur, Ramakrishna V

    2011-09-01

    A three-dimensional nuclear magnetic resonance (NMR) pulse sequence named as hNCOcanH has been described to aid rapid sequential assignment of backbone resonances in (15)N/(13)C-labeled proteins. The experiment has been derived by a simple modification of the previously described HN(C)N pulse sequence [Panchal et al., J. Biomol. NMR 20 (2001) 135-147]; t2 evolution is used to frequency label (13)C' rather than (15)N (similar trick has also been used in the design of hNCAnH pulse sequence from hNcaNH [Frueh et al., JACS, 131 (2009) 12880-12881]). The modification results in a spectrum equivalent to HNCO, but in addition to inter-residue correlation peaks (i.e. Hi , Ci-1), the spectrum also contains additional intra-residue correlation peaks (i.e. Hi-1 , Ci-1) in the direct proton dimension which has maximum resolution. This is the main strength of the experiment and thus, even a small difference in amide (1) H chemical shifts (5-6 Hz) can be used for establishing a sequential connectivity. This experiment in combination with the HNN experiment described previously [Panchal et al., J. Biomol. NMR 20 (2001) 135-147] leads to a more robust assignment protocol for backbone resonances ((1) H(N) , (15)N) than could be derived from the combination of HNN and HN(C)N experiments [Bhavesh et al., Biochemistry, 40 (2001) 14727-14735]. Further, this new protocol enables assignment of (13)C' resonances as well. We believe that the experiment and the protocol presented here will be of immense value for structural-and functional-proteomics research by NMR. Performance of this experiment has been demonstrated using (13)C/(15)N labeled ubiquitin.

  8. Broadband finite-pulse radio-frequency-driven recoupling (fp-RFDR) with (XY8)4(1) super-cycling for homo-nuclear correlations in very high magnetic fields at fast and ultra-fast MAS frequencies.

    Science.gov (United States)

    Shen, Ming; Hu, Bingwen; Lafon, Oliver; Trébosc, Julien; Chen, Qun; Amoureux, Jean-Paul

    2012-10-01

    We demonstrate that inter-residue (13)C-(13)C proximities (of about 380 pm) in uniformly (13)C-labeled proteins can be probed by applying robust first-order recoupling during several milliseconds in single-quantum single-quantum dipolar homo-nuclear correlation (SQ-SQ D-HOMCOR) 2D experiments. We show that the intensity of medium-range homo-nuclear correlations in these experiments is enhanced using broadband first-order finite-pulse radio-frequency-driven recoupling (fp-RFDR) NMR sequence with a nested (XY8)4(1) super-cycling. The robustness and the efficiency of the fp-RFDR-(XY8)4(1) method is demonstrated at high magnetic field (21.1T) and high Magic-Angle Spinning (MAS) speeds (up to 60 kHz). The introduced super-cycling, formed by combining phase inversion and a global four-quantum phase cycle, improves the robustness of fp-RFDR to (i) chemical shift anisotropy (CSA), (ii) spread in isotropic chemical shifts, (iii) rf-inhomogeneity and (iv) hetero-nuclear dipolar couplings for long recoupling times. We show that fp-RFDR-(XY8)4(1) is efficient sans (1)H decoupling, which is beneficial for temperature-sensitive biomolecules. The efficiency and the robustness of fp-RFDR-(XY8)4(1) is investigated by spin dynamics numerical simulations as well as solid-state NMR experiments on [U-(13)C]-L-histidine·HCl, a tetra-peptide (Fmoc-[U-(13)C,(15)N]-Val-[U-(13)C,(15)N]-Ala-[U-(13)C,(15)N]-Phe-Gly-t-Boc) and Al(PO(3))(3).

  9. Characterization via nuclear magnetic resonance of Portland cement and related materials

    Science.gov (United States)

    Edwards, Christopher Lane

    The physicochemical and engineering performance properties of several API class G and H ordinary Portland cements (OPCs) from various foreign and domestic sources have been investigated. The engineering performance properties are found to vary from sample to sample, and sources for this variation were sought out and identified. Magic angle spinning (MAS) 29Si nuclear magnetic resonance (NMR) experiments were marked by unusual relaxation behavior due to paramagnetism inherent in OPCs. A model system was created to mimic the paramagnetism of the cements and the system's relaxation behavior was analyzed. The iron in the calcium aluminoferrite (C4AF) provides the paramagnetism sufficient to substantially increase the relaxation rates of the 29Si in the tricalcium silicate (C3S) and dicalcium silicate (C2S) of cement. Several relaxation techniques were evaluated for analyzing cement relaxation, and saturation recovery was identified as the preferred technique. Correlations of data from the saturation recovery experiments with engineering performance properties, especially the strength development of cement pastes, were obtained facilely. An error analysis of the NMR and engineering performance testing techniques was conducted, which indicated that NMR measurements produced less error than the engineering performance tests. A best practice, modified from the saturation recovery experiment, is proposed for use in property correlations. Additionally, 13C MAS NMR was used to characterize various fluorinated single-walled carbon nanotubes (F-SWNTs), which proved surprisingly effective in attenuating 13C-19F dipolar interactions and quantifying the extent of functionalization present at high degrees of reaction. The mixed-metal nanocluster known as FeMoC was also characterized by MAS NMR. The impact of the paramagnetic Fe3+ in the Keplerate cage on the 31P nuclei in the caged Keggin ion of FeMoC was evident in the greatly reduced relaxation times measured.

  10. Development of a miniature permanent magnetic circuit for nuclear magnetic resonance chip

    Science.gov (United States)

    Lu, Rongsheng; Yi, Hong; Wu, Weiping; Ni, Zhonghua

    2013-07-01

    The existing researches of miniature magnetic circuits focus on the single-sided permanent magnetic circuits and the Halbach permanent magnetic circuits. In the single-sided permanent magnetic circuits, the magnetic flux density is always very low in the work region. In the Halbach permanent magnetic circuits, there are always great difficulties in the manufacturing and assembly process. The static magnetic flux density required for nuclear magnetic resonance(NMR) chip is analyzed based on the signal noise ratio(SNR) calculation model, and then a miniature C-shaped permanent magnetic circuit is designed as the required magnetic flux density. Based on Kirchhoff's law and magnetic flux refraction principle, the concept of a single shimming ring is proposed to improve the performance of the designed magnetic circuit. Using the finite element method, a comparative calculation is conducted. The calculation results demonstrate that the magnetic circuit improved with a single shimming has higher magnetic flux density and better magnetic field homogeneity than the one improved with no shimming ring or double shimming rings. The proposed magnetic circuit is manufactured and its experimental test platform is also built. The magnetic flux density measured in the work region is 0.7 T, which is well coincided with the theoretical design. The spatial variation of the magnetic field is within the range of the instrument error. At last, the temperature dependence of the magnetic flux density produced by the proposed magnetic circuit is investigated through both theoretical analysis and experimental study, and a linear functional model is obtained. The proposed research is crucial for solving the problem in the application of NMR-chip under different environmental temperatures.

  11. Synthesis and structural analysis of 13C-fatty acids

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The 13C-labeled fatty acids octanoic-1-13C acid and palmitic-l-13C acid were synthetically prepared from Ba 13CO3. The yield of the former was more than 90% and that of the latter was above 85%. MS, IR, 1H-NMR and 13NMR were performed to analyze the structures of the two 13C-fatty acids, compared with their unlabeled fatty acids.

  12. Unconventional nuclear magnetic resonance techniques using nanostructured diamond surfaces

    Science.gov (United States)

    Acosta, Victor; Jarmola, Andrey; Budker, Dmitry; Santori, Charles; Huang, Zhihong; Beausoleil, Raymond

    2014-03-01

    Nuclear magnetic resonance (NMR) technologies rely on obtaining high nuclear magnetization, motivating low operating temperatures and high magnetic fields. Dynamic nuclear polarization (DNP) techniques traditionally require another superconducting magnet and THz optics. We seek to use chip-scale devices to polarize nuclei in liquids at room temperature. The technique relies on optical pumping of nitrogen-vacancy (NV) centers and subsequent transfer of polarization to nuclei via hyperfine interaction, spin diffusion, and heteronuclear polarization transfer. We expect efficient polarization transfer will be realized by maximizing the diamond surface area. We have fabricated densely-packed (50 % packing fraction), high-aspect-ratio (10+) nanopillars over mm2 regions of the diamond surface. Pillars designed to have a few-hundred-nanometer diameter act as optical antennas, reducing saturation intensity. We also report progress in using nanopillar arrays as sensitive optical detectors of nano-scale NMR by measuring NV center Zeeman shifts produced by nearby external nuclei. The enhanced surface area increases the effective density of NV centers which couple to external nuclei. Combining these techniques may enable, e.g., identification of trace analytes and molecular imaging.

  13. Microwave-gated dynamic nuclear polarization

    DEFF Research Database (Denmark)

    Bornet, Aurélien; Pinon, Arthur; Jhajharia, Aditya

    2016-01-01

    Dissolution dynamic nuclear polarization (D-DNP) has become a method of choice to enhance signals in nuclear magnetic resonance (NMR). Recently, we have proposed to combine cross-polarization (CP) with D-DNP to provide high polarization P((13)C) in short build-up times. In this paper, we show...

  14. Clinical NOE 13C MRS for neuropsychiatric disorders of the frontal lobe

    Science.gov (United States)

    Sailasuta, Napapon; Robertson, Larry W.; Harris, Kent C.; Gropman, Andrea L.; Allen, Peter S.; Ross, Brian D.

    2008-12-01

    In this communication, a scheme is described whereby in vivo 13C MRS can safely be performed in the frontal lobe, a human brain region hitherto precluded on grounds of SAR, but important in being the seat of impaired cognitive function in many neuropsychiatric and developmental disorders. By combining two well known features of 13C NMR—the use of low power NOE and the focus on 13C carbon atoms which are only minimally coupled to protons, we are able to overcome the obstacle of SAR and develop means of monitoring the 13C fluxes of critically important metabolic pathways in frontal brain structures of normal volunteers and patients. Using a combination of low-power WALTZ decoupling, variants of random noise for nuclear overhauser effect enhancement it was possible to reduce power deposition to 20% of the advised maximum specific absorption rate (SAR). In model solutions 13C signal enhancement achieved with this scheme were comparable to that obtained with WALTZ-4. In human brain, the low power procedure effectively determined glutamine, glutamate and bicarbonate in the posterior parietal brain after [1- 13C] glucose infusion. The same 13C enriched metabolites were defined in frontal brain of human volunteers after administration of [1- 13C] acetate, a recognized probe of glial metabolism. Time courses of incorporation of 13C into cerebral glutamate, glutamine and bicarbonate were constructed. The results suggest efficacy for measurement of in vivo cerebral metabolic rates of the glutamate-glutamine and tricarboxylic acid cycles in 20 min MR scans in previously inaccessible brain regions in humans at 1.5T. We predict these will be clinically useful biomarkers in many human neuropsychiatric and genetic conditions.

  15. A single-quantum methyl {sup 13}C-relaxation dispersion experiment with improved sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Lundstroem, Patrik; Vallurupalli, Pramodh [University of Toronto, Departments of Medical Genetics, Biochemistry and Chemistry (Canada); Religa, Tomasz L. [Medical Research Council Centre for Protein Engineering (United Kingdom); Dahlquist, Frederick W. [University of California at Santa Barbara, Department of Chemistry and Biochemistry (United States); Kay, Lewis E. [University of Toronto, Departments of Medical Genetics, Biochemistry and Chemistry (Canada)], E-mail: kay@pound.med.utoronto.ca

    2007-05-15

    A pulse sequence is described for recording single-quantum {sup 13}C-methyl relaxation dispersion profiles of {sup 13}C-selectively labeled methyl groups in proteins that offers significant improvements in sensitivity relative to existing approaches where initial magnetization derives from {sup 13}C polarization. Sensitivity gains in the new experiment are achieved by making use of polarization from {sup 1}H spins and {sup 1}H {sup {yields}} {sup 13}C {sup {yields}} {sup 1}H type magnetization transfers. Its utility has been established by applications involving three different protein systems ranging in molecular weight from 8 to 28 kDa, produced using a number of different selective labeling approaches. In all cases exchange parameters from both {sup 13}C{sup {yields}}{sup 1}H and {sup 1}H {sup {yields}} {sup 13}C {sup {yields}} {sup 1}H classes of experiment are in good agreement, with gains in sensitivity of between 1.7 and 4-fold realized using the new scheme.

  16. Nuclear magnetic and quadrupole resonance studies of the stripes materials

    Energy Technology Data Exchange (ETDEWEB)

    Grafe, H.-J., E-mail: h.grafe@ifw-dresden.de [IFW Dresden, Institute for Solid State Research, P.O. Box 270116, D-01171 Dresden (Germany)

    2012-11-01

    Nuclear Magnetic and Quadrupole Resonance (NMR/NQR) is a powerful tool to probe electronic inhomogeneities in correlated electron systems. Its local character allows for probing different environments due to spin density modulations or inhomogeneous doping distributions emerging from the correlations in these systems. In fact, NMR/NQR is not only sensitive to magnetic properties through interaction of the nuclear spin, but also allows to probe the symmetry of the charge distribution and its homogeneity, as well as structural modulations, through sensitivity to the electric field gradient (EFG). We review the results of NMR and NQR in the cuprates from intrinsic spatial variations of the hole concentration in the normal state to stripe order at low temperatures, thereby keeping in mind the influence of doping induced disorder and inhomogeneities. Finally, we briefly discuss NQR evidence for local electronic inhomogeneities in the recently discovered iron pnictides, suggesting that electronic inhomogeneities are a common feature of correlated electron systems.

  17. Observation of nuclear magnetic order in solid 3He

    DEFF Research Database (Denmark)

    Halperin, W.P.; Archie, C.N.; Rasmussen, Finn Berg

    1974-01-01

    Measurements of T dp/dT have been made along the He3 melting curve near an anomaly at Ts=1.17 mK. It is found that the solid-He3 entropy decreases by 80% in an interval of 100 μK at Ts. This is attributed to onset of nuclear magnetic order.......Measurements of T dp/dT have been made along the He3 melting curve near an anomaly at Ts=1.17 mK. It is found that the solid-He3 entropy decreases by 80% in an interval of 100 μK at Ts. This is attributed to onset of nuclear magnetic order....

  18. Acetylcholinesterase-catalyzed acetate - water oxygen exchange studied by /sup 13/C-NMR

    Energy Technology Data Exchange (ETDEWEB)

    Van Etten, R.L.; Dayton, B.; Cortes, S.

    1986-05-01

    The kinetics of the oxygen exchange reaction between (l-/sup 13/C,/sup 18/O/sub 2/)acetate and H/sub 2//sup 16/O catalyzed by homogeneous acetyl-cholinesterase from the electric eel, Electrophorus electricus, was studied using the /sup 18/O-isotope-induced shift on /sup 13/C-nuclear magnetic resonance spectra. Pseudo-first-order rate constants for the exchange reactions were determined at pH values from 4.5 to 8. The exchange reaction exhibits a maximum at pH 5.8. The apparent catalytic rate constant for the exchange reaction is 10/sup 2/ to 10/sup 4/ times smaller than that for the deacylation of the acetyl-enzyme intermediate over the pH range tested. Oxygen exchange occurs by a random sequential pathway rather than by multiple (coupled) exchange. The inhibition of acetylcholinesterase by sodium acetate showed a sigmoidal dependence on pH, with K/sub i/ increasing 2.5 orders of magnitude over the pH range. Protonation of an active site residue having an apparent pKa of 6.8 is associated with an increase in acetate binding. Deacylation also exhibits a sigmoidal dependence on (H/sup +/). The experimental data fits titration curves with inflection points at 5.0 +/- 0.3 and 6.7 +/-0.1. Results support the role of histidine in acetylation of the active site serine, but the conjugate base of another active site residue with a pKa of 5.0 appears necessary for maximal catalytic activity in both the deacylation and exchange reactions.

  19. Advances in Zero-Field Nuclear Magnetic Resonance Spectroscopy

    OpenAIRE

    Theis, Thomas

    2012-01-01

    In the course of the last century, Nuclear magnetic resonance (NMR) has become a powerful and ubiquitous analytical tool for the determination of molecular identity, structure, and function. Traditionally, the great analytical power of NMR comes at the cost of mobility and large expenses for cryogenic cooling. This thesis presents how zero-field NMR detected with an atomic magnetometer is emerging as a new, potentially portable and cost-effective modality of NMR with the ability of providing ...

  20. A Multidisciplinary Approach to High Throughput Nuclear Magnetic Resonance Spectroscopy

    OpenAIRE

    Hossein Pourmodheji; Ebrahim Ghafar-Zadeh; Sebastian Magierowski

    2016-01-01

    Nuclear Magnetic Resonance (NMR) is a non-contact, powerful structure-elucidation technique for biochemical analysis. NMR spectroscopy is used extensively in a variety of life science applications including drug discovery. However, existing NMR technology is limited in that it cannot run a large number of experiments simultaneously in one unit. Recent advances in micro-fabrication technologies have attracted the attention of researchers to overcome these limitations and significantly accelera...

  1. Demonstration of Quantum Entanglement Control Using Nuclear Magnetic Resonance

    Institute of Scientific and Technical Information of China (English)

    XIE Jing-Yi; ZHANG Jing-Fu; DENG Zhi-Wei; LU Zhi-Heng

    2004-01-01

    @@ With the two forms of the quantum entanglement control, the quantum entanglement swapping and preservation are demonstrated in a three-qubit nuclear magnetic resonance quantum computer. The pseudopure state is prepared to represent the quantum entangled states through macroscopic signals. Entanglement swapping is directly realized by a swap operation. By controlling the interactions between the system and its environment,we can preserve an initial entangled state for a longer time. The experimental results are in agreement with the experiment.

  2. Analysis of the transient response of nuclear spins in GaAs with/without nuclear magnetic resonance

    Science.gov (United States)

    Rasly, Mahmoud; Lin, Zhichao; Yamamoto, Masafumi; Uemura, Tetsuya

    2016-05-01

    As an alternative to studying the steady-state responses of nuclear spins in solid state systems, working within a transient-state framework can reveal interesting phenomena. The response of nuclear spins in GaAs to a changing magnetic field was analyzed based on the time evolution of nuclear spin temperature. Simulation results well reproduced our experimental results for the transient oblique Hanle signals observed in an all-electrical spin injection device. The analysis showed that the so called dynamic nuclear polarization can be treated as a cooling tool for the nuclear spins: It works as a provider to exchange spin angular momentum between polarized electron spins and nuclear spins through the hyperfine interaction, leading to an increase in the nuclear polarization. In addition, a time-delay of the nuclear spin temperature with a fast sweep of the external magnetic field produces a possible transient state for the nuclear spin polarization. On the other hand, the nuclear magnetic resonance acts as a heating tool for a nuclear spin system. This causes the nuclear spin temperature to jump to infinity: i.e., the average nuclear spins along with the nuclear field vanish at resonant fields of 75As, 69Ga and 71Ga, showing an interesting step-dip structure in the oblique Hanle signals. These analyses provide a quantitative understanding of nuclear spin dynamics in semiconductors for application in future computation processing.

  3. Analysis of the transient response of nuclear spins in GaAs with/without nuclear magnetic resonance

    Directory of Open Access Journals (Sweden)

    Mahmoud Rasly

    2016-05-01

    Full Text Available As an alternative to studying the steady-state responses of nuclear spins in solid state systems, working within a transient-state framework can reveal interesting phenomena. The response of nuclear spins in GaAs to a changing magnetic field was analyzed based on the time evolution of nuclear spin temperature. Simulation results well reproduced our experimental results for the transient oblique Hanle signals observed in an all-electrical spin injection device. The analysis showed that the so called dynamic nuclear polarization can be treated as a cooling tool for the nuclear spins: It works as a provider to exchange spin angular momentum between polarized electron spins and nuclear spins through the hyperfine interaction, leading to an increase in the nuclear polarization. In addition, a time-delay of the nuclear spin temperature with a fast sweep of the external magnetic field produces a possible transient state for the nuclear spin polarization. On the other hand, the nuclear magnetic resonance acts as a heating tool for a nuclear spin system. This causes the nuclear spin temperature to jump to infinity: i.e., the average nuclear spins along with the nuclear field vanish at resonant fields of 75As, 69Ga and 71Ga, showing an interesting step-dip structure in the oblique Hanle signals. These analyses provide a quantitative understanding of nuclear spin dynamics in semiconductors for application in future computation processing.

  4. Coupling XRD, EXAFS, and 13C NMR to study the effect of the carbon stoichiometry on the local structure of UC(1±x).

    Science.gov (United States)

    Carvajal Nuñez, U; Martel, L; Prieur, D; Lopez Honorato, E; Eloirdi, R; Farnan, I; Vitova, T; Somers, J

    2013-10-07

    A series of uranium carbide samples, prepared by arc melting with a C/U ratio ranging from 0.96 to 1.04, has been studied by X-ray diffraction (XRD), (13)C nuclear magnetic resonance (NMR), and extended X-ray absorption fine structure (EXAFS). XRD determines phase uniqueness and the increase of the lattice parameter versus the carbon content. In contrast, (13)C NMR detects the different carbon environments in the lattice and in this study, clearly identifies the presence of discrete peaks for carbon in the octahedral lattice site in UC and an additional peak associated with excess carbon in hyperstoichiometric samples. Two peaks associated with different levels of carbon deficiency are detected for all hypostoichiometric compositions. More than one carbon environment is always detected by (13)C NMR. This exemplifies the difficulty in obtaining a perfect stoichiometric uranium monocarbide UC(1.00). The (13)C MAS spectra of uranium carbides exhibit the effects resulting from the carbon content on both the broadening of the peaks and on the Knight shift. An abrupt spectral change occurs between hypo- and hyperstoichiometric samples. The results obtained by EXAFS highlight subtle differences between the different stoichiometries, and in the hyperstoichiometric samples, the EXAFS results are consistent with the excess carbon atoms being in the tetrahedral interstitial position.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. {sup 13}C-{sup 13}C NOESY spectra of a 480 kDa protein: solution NMR of ferritin

    Energy Technology Data Exchange (ETDEWEB)

    Matzapetakis, Manolis; Turano, Paola [University of Florence, Department of Chemistry, CERM (Italy); Theil, Elizabeth C. [Children' s Hospital Oakland Research Institute, CeBIC (Council for BioIron at CHORI) (United States); Bertini, Ivano [University of Florence, Department of Chemistry, CERM (Italy)], E-mail: ivanobertini@cerm.unifi.it

    2007-07-15

    Molecular size has limited solution NMR analyses of proteins. We report {sup 13}C-{sup 13}C NOESY experiments on a 480 kDa protein, the multi-subunit ferritin nanocage with gated pores. By exploiting {sup 13}C-resonance-specific chemical shifts and spin diffusion effects, we identified 75% of the amino acids, with intraresidue C-C connectivities between nuclei separated by 1-4 bonds. These results show the potential of {sup 13}C-{sup 13}C NOESY for solution studies of molecular assemblies >100 kDa.

  7. Identification of archaeological triterpenic resins by the non-separative techniques FTIR and 13C NMR: the case of Pistacia resin (mastic) in comparison with frankincense.

    Science.gov (United States)

    Bruni, Silvia; Guglielmi, Vittoria

    2014-01-01

    The use of spectroscopic techniques such as Fourier-transform infrared (FTIR) spectroscopy and carbon 13 nuclear magnetic resonance ((13)C NMR) using the J-mod experiment is proposed as an effective alternative to gas chromatography-mass spectrometry (GC-MS) for the analysis and identification of natural resin samples found in archaeological environments. The spectral features of the most common diterpenic and triterpenic resins and also two gum-resins are reported and discussed for both techniques. The analytical procedure based on the combined use of FTIR and (13)C NMR is then applied to two archaeological samples from the Milano of the Roman age allowing their identification as Pistacia resin, or mastic, as confirmed by the traditional GC-MS method, and also elucidating some effects of aging on such material.

  8. Molecular interactions between green tea catechins and cheese fat studied by solid-state nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Rashidinejad, Ali; Birch, Edward J; Hindmarsh, Jason; Everett, David W

    2017-01-15

    Molecular integrations between green tea catechins and milk fat globules in a cheese matrix were investigated using solid-state magic angle spinning nuclear magnetic resonance spectroscopy. Full-fat cheeses were manufactured containing free catechin or free green tea extract (GTE), and liposomal encapsulated catechin or liposomal encapsulated GTE. Molecular mobility of the carbon species in the cheeses was measured by a wide-line separation technique. The (1)H evolution frequency profile of the (13)C peak at 16ppm obtained for the control cheese and cheeses containing encapsulated polyphenols (catechin or GTE) were similar, however, the spectrum was narrower for cheeses containing free polyphenols. Differences in spectral width indicates changes in the molecular mobility of --CH3- or -C-C-PO4- species through hydrophobic and/or cation-π associations between green tea catechins and cheese fat components. However, the similar spectral profile suggests that encapsulation protects cheese fat from interaction with catechins.

  9. Nuclear Magnetic Resonance-Based Metabolic Comparative Analysis of Two Apple Varieties with Different Resistances to Apple Scab Attacks.

    Science.gov (United States)

    Sciubba, Fabio; Di Cocco, Maria Enrica; Gianferri, Raffaella; Capuani, Giorgio; De Salvador, Flavio Roberto; Fontanari, Marco; Gorietti, Daniela; Delfini, Maurizio

    2015-09-23

    Apple scab, caused by the fungus Venturia inaequalis, is the most serious disease of the apple worldwide. Two cultivars (Malus domestica), having different degrees of resistance against fungi attacks, were analyzed by (1)H and (13)C nuclear magnetic resonance (NMR) spectroscopy. Aqueous and organic extracts of both apple flesh and skin were studied, and over 30 metabolites, classified as organic acids, amino acids, carbohydrates, phenolic compounds, lipids, sterols, and other metabolites, were quantified by means of one-dimensional (1D) and two-dimensional (2D) NMR experiments. The metabolic profiles of the two apple cultivars were compared, and the differences were correlated with the different degrees of resistance to apple scab by means of univariate analysis. Levels of metabolites with known antifungal activity were observed not only to be higher in the Almagold cultivar but also to show different correlation patterns in comparison to Golden Delicious, implying a difference in the metabolic network involved in their biosynthesis.

  10. Nuclear Magnetic Resonance Imaging of Li-ion Battery

    Directory of Open Access Journals (Sweden)

    D. Ohno

    2010-12-01

    Full Text Available Nuclear magnetic resonance (NMR imaging has high sensitivity to proton (1H and lithium (7Li. It is a useful measurement for electrolyte in Li-ion battery. 1H NMR images of lithium ion battery which is composed of LiMn2O4 / LiClO4 + propylene carbonate (PC / Li-metal have been studied. 1H NMR images of electrolyte near cathode material (LiMn2O4 showed anomalous intensity distribution, which was quite inhomogeneous. From NMR images as a function of repetition time (TR, it was concluded that the anomalous intensity distribution was not due to change of relaxation time but an indirect (spatial para-magnetization effect from cathode material. The paramagnetization induced by high magnetic field distorts linearity of magnetic gradient field, leading to apparent intensity variance. This functional image is an easy diagnostic measurement for magnetization of cathode material, which allows the possibility to check uniformity of cathode material and change of magnetization under electrochemical process.

  11. Quantitative velocity distributions via nuclear magnetic resonance flow metering

    Science.gov (United States)

    O'Neill, Keelan T.; Fridjonsson, Einar O.; Stanwix, Paul L.; Johns, Michael L.

    2016-08-01

    We demonstrate the use of Tikhonov regularisation as a data inversion technique to determine the velocity distributions of flowing liquid streams. Regularisation is applied to the signal produced by a nuclear magnetic resonance (NMR) flow measurement system consisting of a pre-polarising permanent magnet located upstream of an Earth's magnetic field NMR detection coil. A simple free induction decay (FID) NMR signal is measured for the flowing stream in what is effectively a 'time-of-flight' measurement. The FID signal is then modelled as a function of fluid velocity and acquisition time, enabling determination of the velocity probability distributions via regularisation. The mean values of these velocity distributions were successfully validated against in-line rotameters. The ability to quantify multi-modal velocity distributions was also demonstrated using a two-pipe system.

  12. DC superconducting quantum interference device usable in nuclear quadrupole resonance and zero field nuclear magnetic spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Non Q. (San Diego, CA); Clarke, John (Berkeley, CA)

    1993-01-01

    A spectrometer for measuring the nuclear quadrupole resonance spectra or the zero-field nuclear magnetic resonance spectra generated by a sample is disclosed. The spectrometer uses an amplifier having a dc SQUID operating in a flux-locked loop for generating an amplified output as a function of the intensity of the signal generated by the sample. The flux-locked loop circuit includes an integrator. The amplifier also includes means for preventing the integrator from being driven into saturation. As a result, the time for the flux-locked loop to recover from the excitation pulses generated by the spectrometer is reduced.

  13. DC superconducting quantum interference device usable in nuclear quadrupole resonance and zero field nuclear magnetic spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Fan, N.Q.; Clarke, J.

    1993-10-19

    A spectrometer for measuring the nuclear quadrupole resonance spectra or the zero-field nuclear magnetic resonance spectra generated by a sample is disclosed. The spectrometer uses an amplifier having a dc SQUID operating in a flux-locked loop for generating an amplified output as a function of the intensity of the signal generated by the sample. The flux-locked loop circuit includes an integrator. The amplifier also includes means for preventing the integrator from being driven into saturation. As a result, the time for the flux-locked loop to recover from the excitation pulses generated by the spectrometer is reduced. 7 figures.

  14. Electronic properties of Cs-intercalated single-walled carbon nanotubes derived from nuclear magnetic resonance

    KAUST Repository

    Abou-Hamad, E

    2011-05-24

    We report on the electronic properties of Cs-intercalated single-walled carbon nanotubes (SWNTs). A detailed analysis of the 13C and 133Cs nuclear magnetic resonance (NMR) spectra reveals an increased metallization of the pristine SWNTs under Cs intercalation. The \\'metallization\\' of CsxC materials where x=0–0.144 is evidenced from the increased local electronic density of states (DOS) n(EF) at the Fermi level of the SWNTs as determined from spin–lattice relaxation measurements. In particular, there are two distinct electronic phases called α and β and the transition between these occurs around x=0.05. The electronic DOS at the Fermi level increases monotonically at low intercalation levels x<0.05 (α-phase), whereas it reaches a plateau in the range 0.05≤x≤0.143 at high intercalation levels (β-phase). The new β-phase is accompanied by a hybridization of Cs(6s) orbitals with C(sp2) orbitals of the SWNTs. In both phases, two types of metallic nanotubes are found with a low and a high local n(EF), corresponding to different local electronic band structures of the SWNTs.

  15. Study of E/Z isomerization of (arylamino)methylidenefuran-2(3H)-ones by (1) H, (13) C, (15) N spectroscopy and DFT calculations in different solvents.

    Science.gov (United States)

    Osipov, Alexander K; Anis'kov, Alexander A; Grinev, Vyacheslav S; Yegorova, Alevtina Yu

    2017-08-01

    The structure and configuration of the series of previously unknown arylaminomethylidenefuran-2(3H)-ones have been determined in solution by (1) H, (13) C, (15) N nuclear magnetic resonance spectroscopy including two-dimensional experiments such as (1) H─(1) H COSY, dqCOSY, (1) H─(13) C HSQC, (1) H─(13) C HMBC. It was found that synthesized substances exist as an equilibrium mixture of E- and Z-enamines in solution. It was established on the basis of density functional theory calculations that the exchange between the two push-pull enamines is a simple rotation around an exocyclic partial double bond that depends on the effect of the solvents. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  16. Monitoring Cancer Response to Treatment with Hyperpolarized 13C MRS

    DEFF Research Database (Denmark)

    Eldirdiri, Abubakr

    Monitoring the cancer response to treatment, non-invasively, by medical imaging is a key element in the management of cancer. For patients undergoing treatment, it is crucial to determine responders from non-responders in order to guide treatment decisions. Currently, PET is the most widely used......, and the patient is exposed to ionizing radiation. The introduction of hyperpolarized 13C MRS has opened completely new possibilities to study the biochemical changes in disease processes. Numerous 13C-labeled compounds were proposed to interrogate various aspects of cancer cell metabolism. The aim of this study...... is to investigate the relevance of [1-13C]pyruvate and [1,4-13C2]fumarate in monitoring the changes in cellular metabolism and necrosis that may occur as a result of cancer therapy. This project also aims to improve existing 13C MRSI methods to efficiently utilize the signal from hyperpolarized 13C substrates...

  17. Decoherence and fluctuation dynamics of the quantum dot nuclear spin bath probed by nuclear magnetic resonance

    Science.gov (United States)

    Chekhovich, Evgeny A.

    2017-06-01

    Dynamics of nuclear spin decoherence and nuclear spin flip-flops in self-assembled InGaAs/GaAs quantum dots are studied experimentally using optically detected nuclear magnetic resonance (NMR). Nuclear spin-echo decay times are found to be in the range 1-4 ms. This is a factor of ~3 longer than in strain-free GaAs/AlGaAs structures and is shown to result from strain-induced quadrupolar effects that suppress nuclear spin flip-flops. The correlation times of the flip-flops are examined using a novel frequency-comb NMR technique and are found to exceed 1 s, a factor of ~1000 longer than in strain-free structures. These findings complement recent studies of electron spin coherence and reveal the paradoxical dual role of the quadrupolar effects in self-assembled quantum dots: large increase of the nuclear spin bath coherence and at the same time significant reduction of the electron spin-qubit coherence. Approaches to increasing electron spin coherence are discussed. In particular the nanohole filled GaAs/AlGaAs quantum dots are an attractive option: while their optical quality matches the self-assembled dots the quadrupolar effects measured in NMR spectra are a factor of 1000 smaller.

  18. Directly detected (55)Mn MRI: application to phantoms for human hyperpolarized (13)C MRI development.

    Science.gov (United States)

    von Morze, Cornelius; Carvajal, Lucas; Reed, Galen D; Swisher, Christine Leon; Tropp, James; Vigneron, Daniel B

    2014-12-01

    In this work we demonstrate for the first time directly detected manganese-55 ((55)Mn) magnetic resonance imaging (MRI) using a clinical 3T MRI scanner designed for human hyperpolarized (13)C clinical studies with no additional hardware modifications. Due to the similar frequency of the (55)Mn and (13)C resonances, the use of aqueous permanganate for large, signal-dense, and cost-effective "(13)C" MRI phantoms was investigated, addressing the clear need for new phantoms for these studies. Due to 100% natural abundance, higher intrinsic sensitivity, and favorable relaxation properties, (55)Mn MRI of aqueous permanganate demonstrates dramatically increased sensitivity over typical (13)C phantom MRI, at greatly reduced cost as compared with large (13)C-enriched phantoms. A large sensitivity advantage (22-fold) was demonstrated. A cylindrical phantom (d=8 cm) containing concentrated aqueous sodium permanganate (2.7 M) was scanned rapidly by (55)Mn MRI in a human head coil tuned for (13)C, using a balanced steady state free precession acquisition. The requisite penetration of radiofrequency magnetic fields into concentrated permanganate was investigated by experiments and high frequency electromagnetic simulations, and found to be sufficient for (55)Mn MRI with reasonably sized phantoms. A sub-second slice-selective acquisition yielded mean image signal-to-noise ratio of ~60 at 0.5 cm(3) spatial resolution, distributed with minimum central signal ~40% of the maximum edge signal. We anticipate that permanganate phantoms will be very useful for testing HP (13)C coils and methods designed for human studies. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. {sup 13}C solid-state n.m.r. spectroscopy of fossil sporopollenins: variation in composition independent of diagenesis

    Energy Technology Data Exchange (ETDEWEB)

    Hemsley, A.R.; Barrie, P.J.; Scott, A.C. [University of London, Egham (United Kingdom). Royal Holloway, Dept. of Biology and Geology

    1995-07-01

    {sup 13}C solid-state nuclear magnetic resonance of sporopollenin from extant and extinct lycopods and gymnosperms shows that this material differs in composition between these major groups. The relative amounts of unsaturated carbon species are lower in the gymnsopersms than in the lycopods in both the modern and fossil material. This suggests that the proportion of unsaturated carbon species present in the fossils is related to that of the original material. Since the fossil material used in this study was obtained from single rock samples, this largely eliminates the possibility that the observed differences in n.m.r. characteristics in fossil spore exines from different species can be attributed to different diagenetic histories. 16 refs., 2 figs.

  20. Recalcitrance and structural analysis by water-only flowthrough pretreatment of (13)C enriched corn stover stem.

    Science.gov (United States)

    Foston, Marcus; Trajano, Heather L; Samuel, Reichel; Wyman, Charles E; He, Jian; Ragauskas, Arthur J

    2015-12-01

    This study presents high temperature water-only continuous flowthrough pretreatment coupled with nuclear magnetic resonance (NMR) as a promising analytical tool to examine the plant cell wall, to understand its recalcitrance (i.e., cell wall resistance to deconstruction), and to probe the chemistry occurring during batch pretreatment of biomass. (13)C-enriched corn stover stems were pretreated at 170°C for 60min with a hot-water flow rate of 20mL/min to control fractionation of the cell wall. This approach helped elucidate the nature of plant cell wall chemical recalcitrance and biomass pretreatment chemistry by tracking cell wall fragmentation as a function of time. Fractions of the reactor effluent were collected in a time-resolved fashion and characterized by various NMR techniques to determine the degree and sequence of fragments released, as well as, the chemical composition, molecular structure, and relative molecular weight of those released fragments.

  1. Analysis of the mechanical properties and characterization by solid state 13C NMR of recycled EVA copolymer/silica composites

    Directory of Open Access Journals (Sweden)

    Giovanni Chaves Stael

    2005-09-01

    Full Text Available The incorporation of micrometer sized silica particles on poly (ethylene-co-vinyl acetate - EVA - residues from the footwear industry was evaluated. The effects of the processing parameters - temperature and mixing ratio - on the mechanical behavior of molded plates of neat recycled EVA and EVA/silica composites were also investigated. The mechanical properties measured by the tensile test, the fractographic analysis by scanning electron microscopy (SEM, and the 13C Nuclear Magnetic Resonance (NMR showed a reduced EVA to silica compatibility. Therefore, incorporation of untreated silica to recycled EVA copolymer produced a slight decrease on the mechanical performance of EVA/silica composites in respect to neat EVA copolymer. The NMR analysis also shows that the crosslinking process on recycled EVA may be occurring at the carbonyl group.

  2. Relaxation and Dephasing in a Two-Electron 13C Nanotube Double Quantum Dot

    DEFF Research Database (Denmark)

    Churchill, H O H; Kuemmeth, Ferdinand; Harlow, J W;

    2009-01-01

    We use charge sensing of Pauli blockade (including spin and isospin) in a two-electron 13C nanotube double quantum dot to measure relaxation and dephasing times. The relaxation time T1 first decreases with a parallel magnetic field and then goes through a minimum in a field of 1.4 T. We attribute...

  3. Simultaneous hyperpolarized (13)C-pyruvate MRI and (18)F-FDG-PET in cancer (hyperPET)

    DEFF Research Database (Denmark)

    Gutte Borgwardt, Henrik; Hansen, Adam E; Henriksen, Sarah T

    2015-01-01

    have named this concept hyper PET. Intravenous injection of the hyperpolarized (13)C-pyruvate results in an increase of (13)C-lactate, (13)C-alanine and (13)C-CO2 ((13)C-HCO3) resonance peaks relative to the tissue, disease and the metabolic state probed. Accordingly, with dynamic nuclear polarization...... (DNP) and use of (13)C-pyruvate it is now possible to directly study the Warburg Effect through the rate of conversion of (13)C-pyruvate to (13)C-lactate. In this study, we combined it with (18)F-FDG-PET that studies uptake of glucose in the cells. A canine cancer patient with a histology verified...... increased (13)C-lactate production, which also corresponded to high (18)F-FDG uptake on PET. This is in agreement with the fact that glycolysis and production of lactate are increased in tumor cells compared to normal cells. Yet, most interestingly, also in the muscle of the forepaw of the dog high (18)F...

  4. Highly sensitive detection of protein biomarkers via nuclear magnetic resonance biosensor with magnetically engineered nanoferrite particles.

    Science.gov (United States)

    Jeun, Minhong; Park, Sungwook; Lee, Hakho; Lee, Kwan Hyi

    Magnetic-based biosensors are attractive for on-site detection of biomarkers due to the low magnetic susceptibility of biological samples. Here, we report a highly sensitive magnetic-based biosensing system that is composed of a miniaturized nuclear magnetic resonance (NMR) device and magnetically engineered nanoferrite particles (NFPs). The sensing performance, also identified as the transverse relaxation (R2) rate, of the NMR device is directly related to the magnetic properties of the NFPs. Therefore, we developed magnetically engineered NFPs (MnMg-NFP) and used them as NMR agents to exhibit a significantly improved R2 rate. The magnetization of the MnMg-NFPs was increased by controlling the Mn and Mg cation concentration and distribution during the synthesis process. This modification of the Mn and Mg cation directly contributed to improving the R2 rate. The miniaturized NMR system, combined with the magnetically engineered MnMg-NFPs, successfully detected a small amount of infectious influenza A H1N1 nucleoprotein with high sensitivity and stability.

  5. Quantitative and Structure Analysis of Cellulose in Tobacco by 13C CP / MAS NMR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Zhu Xiaolan

    2016-07-01

    Full Text Available A new method utilizing 13C cross-polarization/magic angle spinning (CP/MAS nuclear magnetic resonance (NMR spectra was developed for the simultaneous quantitative determination and structure analysis of tobacco cellulose from hot water or acid detergent extraction. A reference spectrum of tobacco noncellulose components was subtracted from the spectrum of each sample to obtain a subspectrum of the cellulose components. The NMR spectra in combination with spectral fitting were analyzed in detail and some parameters, such as the content of cellulose, crystallinity, allomorph composition and lateral dimensions for cellulose elementary fibrils and microfibrils were determined. The quantitative results showed that the average recovery was 94.0% with a relative standard deviation (RSD of 4.6–4.8%. The structure results obtained by the spectral fitting for the cellulose C1-region showed that the main allomorph composition in tobacco cellulose was Iβ. The cellulose crystallinity calculated by the spectral fitting in C4 -region was about 50%. The lateral dimensions for cellulose elementary fibrils and microfibrils were in the range of 3.0–6.0 nm and 6.0–13.0 nm, respectively. Therefore, this NMR method could provide important information on both amount and structure of cellulose in tobacco.

  6. A Critical Evaluation of the Quality of Published (13)C NMR Data in Natural Product Chemistry.

    Science.gov (United States)

    Robien, Wolfgang

    2017-01-01

    Nuclear Magnetic Resonance spectroscopy contributes very efficiently to the structure elucidation process in organic chemistry. Carbon-13 NMR spectroscopy allows direct insight into the skeleton of organic compounds and therefore plays a central role in the structural assignment of natural products. Despite this important contribution, there is no established and well-accepted workflow protocol utilized during the first steps of interpreting spectroscopic data and converting them into structural fragments and then combining them, by considering the given spectroscopic constraints, into a final proposal of structure. The so-called "combinatorial explosion" in the process of structure generation allows in many cases the generation of reasonable alternatives, which are usually ignored during manual interpretation of the measured data leading ultimately to a large number of structural revisions. Furthermore, even when the determined structure is correct, problems may exist such as assignment errors, ignoring chemical shift values, or assigning lines of impurities to the compound under consideration. An extremely large heterogeneity in the presentation of carbon NMR data can be observed, but, as a result of the efficiency and precision of spectrum prediction, the published data can be analyzed in substantial detail.This contribution presents a comprehensive analysis of frequently occurring errors with respect to (13)C NMR spectroscopic data and proposes a straightforward protocol to eliminate a high percentage of the most obvious errors. The procedure discussed can be integrated readily into the processes of submission and peer-reviewing of manuscripts.

  7. Non-stationary (13)C-metabolic flux ratio analysis.

    Science.gov (United States)

    Hörl, Manuel; Schnidder, Julian; Sauer, Uwe; Zamboni, Nicola

    2013-12-01

    (13)C-metabolic flux analysis ((13)C-MFA) has become a key method for metabolic engineering and systems biology. In the most common methodology, fluxes are calculated by global isotopomer balancing and iterative fitting to stationary (13)C-labeling data. This approach requires a closed carbon balance, long-lasting metabolic steady state, and the detection of (13)C-patterns in a large number of metabolites. These restrictions mostly reduced the application of (13)C-MFA to the central carbon metabolism of well-studied model organisms grown in minimal media with a single carbon source. Here we introduce non-stationary (13)C-metabolic flux ratio analysis as a novel method for (13)C-MFA to allow estimating local, relative fluxes from ultra-short (13)C-labeling experiments and without the need for global isotopomer balancing. The approach relies on the acquisition of non-stationary (13)C-labeling data exclusively for metabolites in the proximity of a node of converging fluxes and a local parameter estimation with a system of ordinary differential equations. We developed a generalized workflow that takes into account reaction types and the availability of mass spectrometric data on molecular ions or fragments for data processing, modeling, parameter and error estimation. We demonstrated the approach by analyzing three key nodes of converging fluxes in central metabolism of Bacillus subtilis. We obtained flux estimates that are in agreement with published results obtained from steady state experiments, but reduced the duration of the necessary (13)C-labeling experiment to less than a minute. These results show that our strategy enables to formally estimate relative pathway fluxes on extremely short time scale, neglecting cellular carbon balancing. Hence this approach paves the road to targeted (13)C-MFA in dynamic systems with multiple carbon sources and towards rich media.

  8. Simulation and comparison of coils for Hyperpolarized 13C MRS cardiac metabolism studies in pigs

    DEFF Research Database (Denmark)

    Giovannetti, G.; Hartwig, V.; Frijia, Francesca

    2015-01-01

    -Difference Time-Domain (FDTD) algorithm. Theoretical SNR-vs-depth profiles were calculated for each coil configuration. We believe the paper could be interesting for graduate students and researchers in the field of magnetic resonance coil design and development, especially for 13C studies.......Hyperpolarized 13C Magnetic Resonance represents a promising modality for in vivo spectroscopy since it provides a unique opportunity for the non-invasive assessment of regional cardiac metabolism. Although it represents a powerful tool for the study of the heart physiology in pig models...... with experimental results, for coils performance evaluation in terms of coil resistance, sampleinduced resistance and magnetic field pattern. In particular, coil resistances were calculated from Ohm’s law, while magnetic field patterns and sample induced resistances were calculated using a numerical Finite...

  9. Light nuclear charge measurement with Alpha Magnetic Spectrometer Electromagnetic Calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Basara, Laurent [Trento Institute for Fundamental Physics and Applications, Povo 38123 (Italy); Choutko, Vitaly [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Li, Qiang, E-mail: q.li@cern.ch [Harbin Institute of Technology, Harbin, 150001 (China)

    2016-06-11

    The Alpha Magnetic Spectrometer (AMS) is a high energy particle detector installed and operating on board of the International Space Station (ISS) since May 2011. So far more than 70 billion cosmic ray events have been recorded by AMS. In the present paper the Electromagnetic Calorimeter (ECAL) detector of AMS is used to measure cosmic ray nuclear charge magnitudes up to Z=10. The obtained charge magnitude resolution is about 0.1 and 0.3 charge unit for Helium and Carbon, respectively. These measurements are important for an accurate determination of the interaction probabilities of various nuclei with the AMS materials. The ECAL charge calibration and measurement procedures are presented.

  10. Nuclear magnetic resonance-based quantification of organic diphosphates.

    Science.gov (United States)

    Lenevich, Stepan; Distefano, Mark D

    2011-01-15

    Phosphorylated compounds are ubiquitous in life. Given their central role, many such substrates and analogs have been prepared for subsequent evaluation. Prior to biological experiments, it is typically necessary to determine the concentration of the target molecule in solution. Here we describe a method where concentrations of stock solutions of organic diphosphates and bisphosphonates are quantified using (31)P nuclear magnetic resonance (NMR) spectroscopy with standard instrumentation using a capillary tube with a secondary standard. The method is specific and is applicable down to a concentration of 200 μM. The capillary tube provides the reference peak for quantification and deuterated solvent for locking.

  11. Thermo-magnetic systems for space nuclear reactors an introduction

    CERN Document Server

    Maidana, Carlos O

    2014-01-01

    Introduces the reader to engineering magnetohydrodynamics applications and presents a comprehensive guide of how to approach different problems found in this multidisciplinary field. An introduction to engineering magnetohydrodynamics, this brief focuses heavily on the design of thermo-magnetic systems for liquid metals, with emphasis on the design of electromagnetic annular linear induction pumps for space nuclear reactors. Alloy systems that are liquid at room temperature have a high degree of thermal conductivity far superior to ordinary non-metallic liquids. This results in their use for

  12. Resonantly detecting axion-mediated forces with nuclear magnetic resonance.

    Science.gov (United States)

    Arvanitaki, Asimina; Geraci, Andrew A

    2014-10-17

    We describe a method based on precision magnetometry that can extend the search for axion-mediated spin-dependent forces by several orders of magnitude. By combining techniques used in nuclear magnetic resonance and short-distance tests of gravity, our approach can substantially improve upon current experimental limits set by astrophysics, and probe deep into the theoretically interesting regime for the Peccei-Quinn (PQ) axion. Our method is sensitive to PQ axion decay constants between 10(9) and 10(12) GeV or axion masses between 10(-6) and 10(-3) eV, independent of the cosmic axion abundance.

  13. Applications of nuclear magnetic resonance sensors to cultural heritage.

    Science.gov (United States)

    Proietti, Noemi; Capitani, Donatella; Di Tullio, Valeria

    2014-04-21

    In recent years nuclear magnetic resonance (NMR) sensors have been increasingly applied to investigate, characterize and monitor objects of cultural heritage interest. NMR is not confined to a few specific applications, but rather its use can be successfully extended to a wide number of different cultural heritage issues. A breakthrough has surely been the recent development of portable NMR sensors which can be applied in situ for non-destructive and non-invasive investigations. In this paper three studies illustrating the potential of NMR sensors in this field of research are reported.

  14. Implementation of Quantum Private Queries Using Nuclear Magnetic Resonance

    Institute of Scientific and Technical Information of China (English)

    WANG Chuan; HAO Liang; ZHAO Lian-Jie

    2011-01-01

    @@ We present a modified protocol for the realization of a quantum private query process on a classical database.Using one-qubit query and CNOT operation,the query process can be realized in a two-mode database.In the query process,the data privacy is preserved as the sender would not reveal any information about the database besides her query information,and the database provider cannot retain any information about the query.We implement the quantum private query protocol in a nuclear magnetic resonance system.The density matrix of the memory registers are constructed.

  15. Applications of Nuclear Magnetic Resonance Sensors to Cultural Heritage

    Directory of Open Access Journals (Sweden)

    Noemi Proietti

    2014-04-01

    Full Text Available In recent years nuclear magnetic resonance (NMR sensors have been increasingly applied to investigate, characterize and monitor objects of cultural heritage interest. NMR is not confined to a few specific applications, but rather its use can be successfully extended to a wide number of different cultural heritage issues. A breakthrough has surely been the recent development of portable NMR sensors which can be applied in situ for non-destructive and non-invasive investigations. In this paper three studies illustrating the potential of NMR sensors in this field of research are reported.

  16. Random matrix theory in biological nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Lacelle, S

    1984-01-01

    The statistical theory of energy levels or random matrix theory is presented in the context of the analysis of chemical shifts of nuclear magnetic resonance (NMR) spectra of large biological systems. Distribution functions for the spacing between nearest-neighbor energy levels are discussed for uncorrelated, correlated, and random superposition of correlated energy levels. Application of this approach to the NMR spectra of a vitamin, an antibiotic, and a protein demonstrates the state of correlation of an ensemble of energy levels that characterizes each system. The detection of coherent and dissipative structures in proteins becomes feasible with this statistical spectroscopic technique. PMID:6478032

  17. 11B nuclear magnetic resonance in boron-doped diamond

    Directory of Open Access Journals (Sweden)

    Miwa Murakami, Tadashi Shimizu, Masataka Tansho and Yoshihiko Takano

    2008-01-01

    Full Text Available This review summarizes recent results obtained by 11B solid-state nuclear magnetic resonance (NMR on boron-doped diamond, grown by the high-pressure high-temperature (HPHT or chemical vapor deposition techniques. Simple single-pulse experiments as well as advanced two-dimensional NMR experiments were applied to the boron sites in diamond. It is shown that magic-angle spinning at magnetic fields above 10 T is suitable for observation of high-resolution 11B spectra of boron-doped diamond. For boron-doped HPHT diamonds, the existence of the excess boron that does not contribute to electrical conductivity was confirmed and its 11B NMR signal was characterized. The point-defect structures (B+H complexes and -B-B-/-B-C-B- clusters, postulated previously for the excess boron, were discarded and graphite-like structures were assigned instead.

  18. Synthesis and biosynthesis of {sup 13}C-, {sup 15}N-labeled deoxynucleosides useful for biomolecular structural determinations

    Energy Technology Data Exchange (ETDEWEB)

    Ashburn, D.A.; Garcia, K.; Hanners, J.L.; Silks, L.A. III; Unkefer, C.J. [Los Alamos National Laboratory, NM (United States)

    1994-12-01

    Currently, there is a great emphasis on elucidating the structure, function, and dynamics of DNA. Much of the research involved in this study uses nuclear magnetic resonance (NMR) spectroscopy. Effective use of NMR spectroscopy for DNA molecules with mw > 10,000 requires stable isotope enrichment. We present strategies for site-specific isotopic labeling of the purine bases adenosine and guanosine and the biosynthesis of (U-{sup 13}C, {sup 15}N) DNA from methylotropic bacteria. With commercially available 6-chloropurine, an effective two-step route leads to 2{prime}-deoxy-(amino-{sup 15}N)adenosine (dA). The resulting d(amino-{sup 15}N)A is used in a series of reactions to synthesize 2{prime}-deoxy-(2-{sup 13}C,1,amino-{sup 15}N{sub 2})guanosine or any combination thereof. An improved biosynthesis of labeled DNA has been accomplished using Methylobacterium extorquens AS1. Each liter of growth medium contains 4 g of methanol to yield 1 g of lyophilized cells. As much as 200 mg of RNA per liter of culture has been obtained. We are currently developing large-scale isolation protocols. General synthetic pathways to oligomeric DNA will be presented.

  19. Polymeric proanthocyanidins 13C NMR studies of procyanidins

    Science.gov (United States)

    Lawrence J. Porter; Roger H. Newman; Lai Yeap Foo; Herbert Wong; Richard W. Hemingway

    1982-01-01

    Proanthocyanidin polymers have been shown to consist entirely of flavan-3-ol units by a combination of techniques including 13C n.m.r. spectroscopy. The 13C n.m.r. spectra of the polymers and related molecules are now considered in more detail. Prior to this study UC n.m.r. data has been published of procyanidins and...

  20. 1H and 13C NMR study of perdeuterated pyrazoles

    OpenAIRE

    Jimeno, María Luisa; Jagerovic, Nadine; Elguero, José; Junk, Thomas; Catallo, W. James

    1997-01-01

    The 1H and 13C chemical shifts as well as the 1H–2H and 2H–13C coupling constants of perdeuterated 3,5-dimethylpyrazole and 3,5-diphenylpyrazole have been measured and the values compared with those of the unlabelled compounds.

  1. Development of Metallic Magnetic Calorimeters for Nuclear Safeguards Applications

    Energy Technology Data Exchange (ETDEWEB)

    Bates, Cameron Russell [Univ. of California, Berkeley, CA (United States)

    2015-03-11

    Many nuclear safeguards applications could benefit from high-resolution gamma-ray spectroscopy achievable with metallic magnetic calorimeters. This dissertation covers the development of a system for these applications based on gamma-ray detectors developed at the University of Heidelberg. It demonstrates new calorimeters of this type, which achieved an energy resolution of 45.5 eV full-width at half-maximum at 59.54 keV, roughly ten times better than current state of the art high purity germanium detectors. This is the best energy resolution achieved with a gamma-ray metallic magnetic calorimeter at this energy to date. In addition to demonstrating a new benchmark in energy resolution, an experimental system for measuring samples with metallic magnetic calorimeters was constructed at Lawrence Livermore National Laboratory. This system achieved an energy resolution of 91.3 eV full-width at half-maximum at 59.54 keV under optimal conditions. Using this system it was possible to characterize the linearity of the response, the count-rate limitations, and the energy resolution as a function of temperature of the new calorimeter. With this characterization it was determined that it would be feasible to measure 242Pu in a mixed isotope plutonium sample. A measurement of a mixed isotope plutonium sample was performed over the course of 12 days with a single two-pixel metallic magnetic calorimeter. The relative concentration of 242Pu in comparison to other plutonium isotopes was determined by direct measurement to less than half a percent accuracy. This is comparable with the accuracy of the best-case scenario using traditional indirect methods. The ability to directly measure the relative concentration of 242Pu in a sample could enable more accurate accounting and detection of indications of undeclared activities in nuclear safeguards, a better constraint on source material in forensic samples containing plutonium, and improvements in verification in a future plutonium

  2. Glycolysis and the pentose phosphate pathway after human traumatic brain injury: microdialysis studies using 1,2-(13)C2 glucose.

    Science.gov (United States)

    Jalloh, Ibrahim; Carpenter, Keri L H; Grice, Peter; Howe, Duncan J; Mason, Andrew; Gallagher, Clare N; Helmy, Adel; Murphy, Michael P; Menon, David K; Carpenter, T Adrian; Pickard, John D; Hutchinson, Peter J

    2015-01-01

    Increased 'anaerobic' glucose metabolism is observed after traumatic brain injury (TBI) attributed to increased glycolysis. An alternative route is the pentose phosphate pathway (PPP), which generates putatively protective and reparative molecules. To compare pathways we employed microdialysis to perfuse 1,2-(13)C2 glucose into the brains of 15 TBI patients and macroscopically normal brain in six patients undergoing surgery for benign tumors, and to simultaneously collect products for nuclear magnetic resonance (NMR) analysis. (13)C enrichment for glycolytic 2,3-(13)C2 lactate was the median 5.4% (interquartile range (IQR) 4.6-7.5%) in TBI brain and 4.2% (2.4-4.4%) in 'normal' brain (P<0.01). The ratio of PPP-derived 3-(13)C lactate to glycolytic 2,3-(13)C2 lactate was median 4.9% (3.6-8.2%) in TBI brain and 6.7% (6.3-8.9%) in 'normal' brain. An inverse relationship was seen for PPP-glycolytic lactate ratio versus PbtO2 (r=-0.5, P=0.04) in TBI brain. Thus, glycolytic lactate production was significantly greater in TBI than 'normal' brain. Several TBI patients exhibited PPP-lactate elevation above the 'normal' range. There was proportionally greater PPP-derived lactate production with decreasing PbtO2. The study raises questions about the roles of the PPP and glycolysis after TBI, and whether they can be manipulated to achieve a better outcome. This study is the first direct comparison of glycolysis and PPP in human brain.

  3. Intramolecular N-glycan/polypeptide interactions observed at multiple N-glycan remodeling steps through [(13)C,(15)N]-N-acetylglucosamine labeling of immunoglobulin G1.

    Science.gov (United States)

    Barb, Adam W

    2015-01-20

    Asparagine-linked (N) glycosylation is a common eukaryotic protein modification that affects protein folding, function, and stability through intramolecular interactions between N-glycan and polypeptide residues. Attempts to characterize the structure-activity relationship of each N-glycan are hindered by inherent properties of the glycoprotein, including glycan conformational and compositional heterogeneity. These limitations can be addressed by using a combination of nuclear magnetic resonance techniques following enzymatic glycan remodeling to simultaneously generate homogeneous glycoforms. However, widely applicable methods do not yet exist. To address this technological gap, immature glycoforms of the immunoglobulin G1 fragment crystallizable (Fc) were isolated in a homogeneous state and enzymatically remodeled with [(13)C,(15)N]-N-acetylglucosamine (GlcNAc). UDP-[(13)C,(15)N]GlcNAc was synthesized enzymatically in a one-pot reaction from [(13)C]glucose and [(15)N-amido]glutamine. Modifying Fc with recombinantly expressed glycosyltransferases (Gnt1 and Gnt2) and UDP-[(13)C,(15)N]GlcNAc resulted in complete glycoform conversion as judged by mass spectrometry. Two-dimensional heteronuclear single-quantum coherence spectra of the Gnt1 product, containing a single [(13)C,(15)N]GlcNAc residue on each N-glycan, showed that the N-glycan is stabilized through interactions with polypeptide residues. Similar spectra of homogeneous glycoforms, halted at different points along the N-glycan remodeling pathway, revealed the presence of an increased level of interaction between the N-glycan and polypeptide at each step, including mannose trimming, as the N-glycan was converted to a complex-type, biantennary form. Thus, conformational restriction increases as Fc N-glycan maturation proceeds. Gnt1 and Gnt2 catalyze fundamental reactions in the synthesis of every glycoprotein with a complex-type N-glycan; thus, the strategies presented herein can be applied to a broad range of

  4. Intramolecular N-Glycan/Polypeptide Interactions Observed at Multiple N-Glycan Remodeling Steps through [13C,15N]-N-Acetylglucosamine Labeling of Immunoglobulin G1

    Science.gov (United States)

    2014-01-01

    Asparagine-linked (N) glycosylation is a common eukaryotic protein modification that affects protein folding, function, and stability through intramolecular interactions between N-glycan and polypeptide residues. Attempts to characterize the structure–activity relationship of each N-glycan are hindered by inherent properties of the glycoprotein, including glycan conformational and compositional heterogeneity. These limitations can be addressed by using a combination of nuclear magnetic resonance techniques following enzymatic glycan remodeling to simultaneously generate homogeneous glycoforms. However, widely applicable methods do not yet exist. To address this technological gap, immature glycoforms of the immunoglobulin G1 fragment crystallizable (Fc) were isolated in a homogeneous state and enzymatically remodeled with [13C,15N]-N-acetylglucosamine (GlcNAc). UDP-[13C,15N]GlcNAc was synthesized enzymatically in a one-pot reaction from [13C]glucose and [15N-amido]glutamine. Modifying Fc with recombinantly expressed glycosyltransferases (Gnt1 and Gnt2) and UDP-[13C,15N]GlcNAc resulted in complete glycoform conversion as judged by mass spectrometry. Two-dimensional heteronuclear single-quantum coherence spectra of the Gnt1 product, containing a single [13C,15N]GlcNAc residue on each N-glycan, showed that the N-glycan is stabilized through interactions with polypeptide residues. Similar spectra of homogeneous glycoforms, halted at different points along the N-glycan remodeling pathway, revealed the presence of an increased level of interaction between the N-glycan and polypeptide at each step, including mannose trimming, as the N-glycan was converted to a complex-type, biantennary form. Thus, conformational restriction increases as Fc N-glycan maturation proceeds. Gnt1 and Gnt2 catalyze fundamental reactions in the synthesis of every glycoprotein with a complex-type N-glycan; thus, the strategies presented herein can be applied to a broad range of glycoprotein

  5. Characterizing crystal disorder of trospium chloride: a comprehensive,(13) C CP/MAS NMR, DSC, FTIR, and XRPD study.

    Science.gov (United States)

    Urbanova, Martina; Sturcova, Adriana; Brus, Jiri; Benes, Hynek; Skorepova, Eliska; Kratochvil, Bohumil; Cejka, Jan; Sedenkova, Ivana; Kobera, Libor; Policianova, Olivia; Sturc, Antonin

    2013-04-01

    Analysis of C cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), and X-ray powder diffraction data of trospium chloride (TCl) products crystallized from different mixtures of water-ethanol [φ(EtOH) = 0.5-1.0] at various temperatures (0°C, 20°C) and initial concentrations (saturated solution, 30%-50% excess of solvent) revealed extensive structural variability of TCl. Although (13) C CP/MAS NMR spectra indicated broad variety of structural phases arising from molecular disorder, temperature-modulated DSC identified presence of two distinct components in the products. FTIR spectra revealed alterations in the hydrogen bonding network (ionic hydrogen bond formation), whereas the X-ray diffraction reflected unchanged unit cell parameters. These results were explained by a two-component character of TCl products in which a dominant polymorphic form is accompanied by partly separated nanocrystalline domains of a secondary phase that does not provide clear Bragg reflections. These phases slightly differ in the degree of molecular disorder, in the quality of crystal lattice and hydrogen bonding network. It is also demonstrated that, for the quality control of such complex products, (13) C CP/MAS NMR spectroscopy combined with factor analysis (FA) can satisfactorily be used for categorizing the individual samples: FA of (13) C CP/MAS NMR spectra found clear relationships between the extent of molecular disorder and crystallization conditions. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:1235-1248, 2013.

  6. Deuterium isotope effects on 13C chemical shifts of 10-Hydroxybenzo[h]quinolines

    DEFF Research Database (Denmark)

    Hansen, Poul Erik; Kamounah, Fadhil S.; Gryko, Daniel T.

    2013-01-01

    to be negative, indicating transmission via the hydrogen bond. In addition unusual long-range effects are seen. Structures, NMR chemical shifts and changes in nuclear shieldings upon deuteriation are calculated using DFT methods. Two-bond deuterium isotope effects on 13C chemical shifts are correlated......Deuterium isotope effects on 13C-NMR chemical shifts are investigated in a series of 10-hydroxybenzo[h]quinolines (HBQ’s) The OH proton is deuteriated. The isotope effects on 13C chemical shifts in these hydrogen bonded systems are rather unusual. The formal four-bond effects are found...... with calculated OH stretching frequencies. Isotope effects on chemical shifts are calculated for systems with OH exchanged by OD. Hydrogen bond potentials are discussed. New and more soluble nitro derivatives are synthesized....

  7. Investigation of α-cluster states in 13C via the (6Li,d) reaction

    CERN Document Server

    Rodrigues, M R D; Horodynski-Matsushigue, L B; Cunsolo, A; Cappuzzello, F; Duarte, J L M; Rodrigues, C L; Ukita, G M; Souza, M A; Miyake, H

    2010-01-01

    The 9Be(6Li,d)13C reaction was used to investigate possible α-cluster states in 13C. The reaction was measured at 25.5 MeV incident energy, employing the São Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion detection technique. Ten out of sixteen known levels of 13C, up to 11 MeV of excitation, were observed and, due to the much improved energy resolution of 50 keV, at least three doublets could be resolved. This work presents a preliminary analysis of five of the most intensely populated states, also in comparison with the results of former transfer studies.

  8. Nuclear conversion theory: molecular hydrogen in non-magnetic insulators

    Science.gov (United States)

    Ilisca, Ernest; Ghiglieno, Filippo

    2016-09-01

    The hydrogen conversion patterns on non-magnetic solids sensitively depend upon the degree of singlet/triplet mixing in the intermediates of the catalytic reaction. Three main `symmetry-breaking' interactions are brought together. In a typical channel, the electron spin-orbit (SO) couplings introduce some magnetic excitations in the non-magnetic solid ground state. The electron spin is exchanged with a molecular one by the electric molecule-solid electron repulsion, mixing the bonding and antibonding states and affecting the molecule rotation. Finally, the magnetic hyperfine contact transfers the electron spin angular momentum to the nuclei. Two families of channels are considered and a simple criterion based on the SO coupling strength is proposed to select the most efficient one. The denoted `electronic' conversion path involves an emission of excitons that propagate and disintegrate in the bulk. In the other denoted `nuclear', the excited electron states are transients of a loop, and the electron system returns to its fundamental ground state. The described model enlarges previous studies by extending the electron basis to charge-transfer states and `continui' of band states, and focuses on the broadening of the antibonding molecular excited state by the solid conduction band that provides efficient tunnelling paths for the hydrogen conversion. After working out the general conversion algebra, the conversion rates of hydrogen on insulating and semiconductor solids are related to a few molecule-solid parameters (gap width, ionization and affinity potentials) and compared with experimental measures.

  9. Relaxation and Dephasing in a Two-Electron 13C Nanotube Double Quantum Dot

    DEFF Research Database (Denmark)

    Churchill, H O H; Kuemmeth, Ferdinand; Harlow, J W

    2009-01-01

    We use charge sensing of Pauli blockade (including spin and isospin) in a two-electron 13C nanotube double quantum dot to measure relaxation and dephasing times. The relaxation time T1 first decreases with a parallel magnetic field and then goes through a minimum in a field of 1.4 T. We attribute...... both results to the spin-orbit-modified electronic spectrum of carbon nanotubes, which at high field enhances relaxation due to bending-mode phonons. The inhomogeneous dephasing time T2* is consistent with previous data on hyperfine coupling strength in 13C nanotubes....

  10. Practical aspects of 13C surface receive coils with active decoupling and tuning circuit

    DEFF Research Database (Denmark)

    Nilsson, Daniel; Mohr, Johan Jacob; Zhurbenko, Vitaliy

    2012-01-01

    Magnetic Resonance Imaging (MRI) of nuclei other than 1H (e.g. 13C) allows for characterisation of metabolic processes. Imaging of such nuclei, however, requires development of sensitive MRI coils. This paper describes the design of surface receive coils for 13C imaging in small animals. The design...... is based on application-specified coil profile and includes impedance matching and balancing circuits. Active decoupling is implemented in order to minimize the influence of the receiving coil on the homogeneity of the transmit-coil field. Measurement results for a coil prototype are presented, including...

  11. Measuring the Muon g-2 Magnetic Storage Field Via Proton Nuclear Magnetic Resonance

    Science.gov (United States)

    Smith, Matthias; Muon g-2 Collaboration Collaboration

    2016-03-01

    The Muon g - 2 experiment at Fermilab aims to measure the muon anomalous magnetic moment, aμ, to a precision of 140 ppb, using a technique that determines the muon spin precession frequency in the highly uniform magnetic field of a storage ring. Both precession frequency and field determination contribute equally to the final systematic uncertainty. The magnetic field is determined from the measurement of free induction decay (FID) signals provided by a matrix of custom proton nuclear magnetic resonance (pNMR) probes. FID simulations show that we can achieve the required precision for extraction of field values compared to systematic contributions. The recently powered muon storage ring is providing data to evaluate the pNMR measurement results. We will describe the performance to date of this system.

  12. COMPARATIVE ASSESSMENT OF NUCLEAR MAGNETIC RELAXATION CHARACTERISTICS OF SUNFLOWER AND RAPESEED LECITHIN

    OpenAIRE

    Lisovaya E. V.; Victorova E. P.; Agafonov O. S.; Kornen N. N.; Shahray T. A.

    2015-01-01

    The article presents a comparative assessment and peculiarities of nuclear magnetic relaxation characteristics of rapeseed and sunflower lecithin. It was established, that lecithin’s nuclear magnetic relaxation characteristics, namely, protons’ spin-spin relaxation time and amplitudes of nuclear magnetic relaxation signals of lecithin components, depend on content of oil’s fat acids and phospholipids, contained in the lecithin. Comparative assessment of protons’ spin-spin relaxation time of r...

  13. Mechanism of Thin Layers Graphite Formation by 13C Implantation and Annealing

    Directory of Open Access Journals (Sweden)

    Gaelle Gutierrez

    2014-04-01

    Full Text Available The mechanism of thin layers graphite (TLG synthesis on a polycrystalline nickel film deposited on SiO2 (300 nm thick/Si(100 has been investigated by 13C implantation of four equivalent graphene monolayers and annealing at moderate temperatures (450–600 °C. During this process, the implanted 13C segregates to the surface. Nuclear Reaction Analyses (NRA are used for the first time in the topic of graphene synthesis to separate the isotopes and to determine the 12C and 13C concentrations at each step. Indeed, a significant part of carbon in the TLG also comes from residual 12C carbon absorbed into the metallic matrix. Raman spectroscopy and imaging are used to determine the main location of each carbon isotope in the TLG. The Raman mappings especially emphasize the role of 12C previously present at the surface that first diffuses along grain boundaries. They play the role of nucleation precursors. Around them the implanted 13C or a mixture of bulk 12C–13C aggregate and further precipitate into graphene-like fragments. Graphenization is effective at around 600 °C. These results point out the importance of controlling carbon incorporation, as well as the importance of preparing a uniform nickel surface, in order to avoid heterogeneous nucleation.

  14. Simultaneous hyperpolarized (13)C-pyruvate MRI and (18)F-FDG-PET in cancer (hyperPET): feasibility of a new imaging concept using a clinical PET/MRI scanner.

    Science.gov (United States)

    Gutte, Henrik; Hansen, Adam E; Henriksen, Sarah T; Johannesen, Helle H; Ardenkjaer-Larsen, Jan; Vignaud, Alexandre; Hansen, Anders E; Børresen, Betina; Klausen, Thomas L; Wittekind, Anne-Mette N; Gillings, Nic; Kristensen, Annemarie T; Clemmensen, Andreas; Højgaard, Liselotte; Kjær, Andreas

    2015-01-01

    In this paper we demonstrate, for the first time, the feasibility of a new imaging concept - combined hyperpolarized (13)C-pyruvate magnetic resonance spectroscopic imaging (MRSI) and (18)F-FDG-PET imaging. This procedure was performed in a clinical PET/MRI scanner with a canine cancer patient. We have named this concept hyper PET. Intravenous injection of the hyperpolarized (13)C-pyruvate results in an increase of (13)C-lactate, (13)C-alanine and (13)C-CO2 ((13)C-HCO3) resonance peaks relative to the tissue, disease and the metabolic state probed. Accordingly, with dynamic nuclear polarization (DNP) and use of (13)C-pyruvate it is now possible to directly study the Warburg Effect through the rate of conversion of (13)C-pyruvate to (13)C-lactate. In this study, we combined it with (18)F-FDG-PET that studies uptake of glucose in the cells. A canine cancer patient with a histology verified local recurrence of a liposarcoma on the right forepaw was imaged using a combined PET/MR clinical scanner. PET was performed as a single-bed, 10 min acquisition, 107 min post injection of 310 MBq (18)F-FDG. (13)C-chemical shift imaging (CSI) was performed just after FDG-PET and 30 s post injection of 23 mL hyperpolarized (13)C-pyruvate. Peak heights of (13)C-pyruvate and (13)C-lactate were quantified using a general linear model. Anatomic (1)H-MRI included axial and coronal T1 vibe, coronal T2-tse and axial T1-tse with fat saturation following gadolinium injection. In the tumor we found clearly increased (13)C-lactate production, which also corresponded to high (18)F-FDG uptake on PET. This is in agreement with the fact that glycolysis and production of lactate are increased in tumor cells compared to normal cells. Yet, most interestingly, also in the muscle of the forepaw of the dog high (18)F-FDG uptake was observed. This was due to activity in these muscles prior to anesthesia, which was not accompanied by a similarly high (13)C-lactate production. Accordingly, this clearly

  15. Synthesis of single wall carbon nanotubes with defined {sup 13}C content

    Energy Technology Data Exchange (ETDEWEB)

    Kramberger, C.; Loeffler, M.; Ruemmeli, M.; Grueneis, A.; Schoenfelder, R.; Gemming, T.; Pichler, T.; Buechner, B. [Leibniz Institute for Solid State Research, 01069 Dresden (Germany); Jost, O. [Technical University of Dresden, 01062 Dresden (Germany)

    2006-11-15

    The synthesis of high quality isotope engineered SWCNT by means of laser ablation and the use of Pt-Rh-Re catalyst mixtures has been established. Optical absorption and Raman spectroscopy as well as transmission electron microscopy are utilized to characterize the obtained SWCNTs with regard to purity and yield. The absence of any ferromagnetic materials, as well as the remarkably low abundance of amorphous carbon renders this material ideal for magnetic studies. The controlled augmentation of {sup 13}C is conveniently confirmed by phonon softening and broadening observed in Raman spectroscopy. Isotope labelling at constant sample quality was achieved in the whole range from 1% {sup 13}C up to 98% {sup 13}C. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Increasing 13C CP-MAS NMR resolution using single crystals: application to model octaethyl porphyrins.

    Science.gov (United States)

    Dugar, Sneha; Fu, Riqiang; Dalal, Naresh S

    2012-08-02

    Octaethyl porphyrin (OEP) and its Ni and Zn derivatives are considered as model compounds in biochemical, photophysical, and fossil fuel chemistry. They have thus been investigated by high-resolution solid-state (13)C NMR using powders, but peak assignment has been difficult because of large line widths. Arguing that a significant cause of broadening might be the anisotropic bulk magnetic susceptibility, we utilized single crystals in our (13)C cross-polarization magic angle spinning (CP-MAS) measurements and observed a nearly 2-fold line narrowing. This enhanced resolution enabled us to assign chemical shifts to each carbon for all the three compounds. The new assignments are now in agreement with X-ray structural data and allowed us to probe the motional dynamics of the methyl and methylene carbons of the OEP side chains. It is apparent that the use of single crystals in (13)C CP-MAS measurements has a significantly wider impact than previously thought.

  17. Properties of K,Rb-intercalated C60 encapsulated inside carbon nanotubes called peapods derived from nuclear magnetic resonance

    KAUST Repository

    Mahfouz, R.

    2015-09-18

    We present a detailed experimental study on how magnetic and electronic properties of Rb,K-intercalated C60 encapsulated inside carbon nanotubes called peapods can be derived from 13C nuclear magnetic resonance investigations. Ring currents do play a basic role in those systems; in particular, the inner cavities of nanotubes offer an ideal environment to investigate the magnetism at the nanoscale. We report the largest diamagnetic shifts down to −68.3 ppm ever observed in carbon allotropes, which is connected to the enhancement of the aromaticity of the nanotube envelope upon intercalation. The metallization of intercalated peapods is evidenced from the chemical shift anisotropy and spin-lattice relaxation (T1) measurements. The observed relaxation curves signal a three-component model with two slow and one fast relaxing components. We assigned the fast component to the unpaired electrons charged C60 that show a phase transition near 100 K. The two slow components can be rationalized by the two types of charged C60 at two different positions with a linear regime following Korringa behavior, which is typical for metallic system and allow us to estimate the density of sate at Fermi level n(EF).

  18. Detection of molecules and cells using nuclear magnetic resonance with magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Rümenapp, Christine, E-mail: ruemenapp@tum.de [Zentralinstitut für Medizintechnik (IMETUM), Technische Universität München, Garching (Germany); Gleich, Bernhard [Zentralinstitut für Medizintechnik (IMETUM), Technische Universität München, Garching (Germany); Mannherz, Hans Georg [Abteilung für Anatomie und Molekulare Embryologie, Ruhr Universität Bochum, Bochum (Germany); Haase, Axel [Zentralinstitut für Medizintechnik (IMETUM), Technische Universität München, Garching (Germany)

    2015-04-15

    For the detection of small molecules, proteins or even cells in vitro, functionalised magnetic nanoparticles and nuclear magnetic resonance measurements can be applied. In this work, magnetic nanoparticles with the size of 5–7 nm were functionalised with antibodies to detect two model systems of different sizes, the protein avidin and Saccharomyces cerevisiae as the model organism. The synthesised magnetic nanoparticles showed a narrow size distribution, which was determined using transmission electron microscopy and dynamic light scattering. The magnetic nanoparticles were functionalised with the according antibodies via EDC/NHS chemistry. The binding of the antigen to magnetic nanoparticles was detected through the change in the NMR T{sub 2} relaxation time at 0.5 T (≈21.7 MHz). In case of a specific binding the particles cluster and the T{sub 2} relaxation time of the sample changes. The detection limit in buffer for FITC-avidin was determined to be 1.35 nM and 10{sup 7} cells/ml for S. cerevisiae. For fluorescent microscopy the avidin molecules were labelled with FITC and for the detection of S. cerevisiae the magnetic nanoparticles were additionally functionalised with rhodamine. The binding of the particles to S. cerevisiae and the resulting clustering was also seen by transmission electron microscopy.

  19. Study of Urban environmental quality through Isotopes δ13C

    Science.gov (United States)

    González-Sosa, E.; Mastachi-Loza, C.; Becerril-Piña, R.; Ramos-Salinas, N. M.

    2012-04-01

    Usually, trees with similar pH values on their bark develop epiphytes of similar species, the acidity to be a factor for growth. The aim of the study was evaluate the air quality through isotope δ13C in order to define the levels of environmental quality in the city of Queretaro, Mexico. In this work were collected at least 4 epiphytes positioned in trees of the species Prosopis Laevigata at 25 sites of Queretaro City. The samples were analyzed for trace elements with an inductively coupled plasma atomic emission spectroscopy (ICP). The collecting took place during dry period, in May and early rain June 2011 period, and on four sectors to identify the spatial distribution of pollution, using isotopic analysis of concentration of δ 13C. According with the results there are significant differences among the species in each of the sampled areas. The 5 February Avenue presented greater diversity and richness of δ13C, followed by those who were surveyed in the proximity of the UAQ and finally in the middle-east area. An average value of δ13C-17.92%, followed by those surveyed in the vicinity of the UAQ that correspond to sector I and II with an concentration of δ13C-17.55% and δ13C-17.22%, and finally the samples collected in trees scattered in the East-Sector II and IV with a value of δ13C-17.02% and δ13C-15.62%, respectively. Also were observed differences between the dry and wet period. It is likely that these results of δ 13C in moist period reflect the drag of the isotopes due to rain events that could mark a trend in the dilution of this element, however there is a trend in terms of abundance and composition of finding more impact in those species sampled in dry period, in May and early June 2011.

  20. Control of coherence among the spins of a single electron and the three nearest neighbor {sup 13}C nuclei of a nitrogen-vacancy center in diamond

    Energy Technology Data Exchange (ETDEWEB)

    Shimo-Oka, T.; Miwa, S.; Suzuki, Y.; Mizuochi, N., E-mail: mizuochi@mp.es.osaka-u.ac.jp [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Kato, H.; Yamasaki, S. [Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Jelezko, F. [Institut für Quantenoptik, Universität Ulm, Albert-Einstein-Allee 11, 89081 Ulm (Germany)

    2015-04-13

    Individual nuclear spins in diamond can be optically detected through hyperfine couplings with the electron spin of a single nitrogen-vacancy (NV) center; such nuclear spins have outstandingly long coherence times. Among the hyperfine couplings in the NV center, the nearest neighbor {sup 13}C nuclear spins have the largest coupling strength. Nearest neighbor {sup 13}C nuclear spins have the potential to perform fastest gate operations, providing highest fidelity in quantum computing. Herein, we report on the control of coherences in the NV center where all three nearest neighbor carbons are of the {sup 13}C isotope. Coherence among the three and four qubits are generated and analyzed at room temperature.

  1. A magnetic tunnel to shelter hyperpolarized fluids

    Energy Technology Data Exchange (ETDEWEB)

    Milani, Jonas, E-mail: jonas.milani@epfl.ch; Vuichoud, Basile; Bornet, Aurélien; Miéville, Pascal; Mottier, Roger [Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), Batochime, CH-1015 Lausanne (Switzerland); Jannin, Sami [Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), Batochime, CH-1015 Lausanne (Switzerland); Bruker BioSpin AG, Industriestrasse 26, CH-8117 Fällanden (Switzerland); Bodenhausen, Geoffrey [Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), Batochime, CH-1015 Lausanne (Switzerland); Département de Chimie, École Normale Supérieure-PSL Research University, 24 rue Lhomond, F-75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris (France); CNRS, UMR 7203 LBM, F-75005 Paris (France)

    2015-02-15

    To shield solutions carrying hyperpolarized nuclear magnetization from rapid relaxation during transfer through low fields, the transfer duct can be threaded through an array of permanent magnets. The advantages are illustrated for solutions containing hyperpolarized {sup 1}H and {sup 13}C nuclei in a variety of molecules.

  2. (13)C metabolic flux analysis of recombinant expression hosts.

    Science.gov (United States)

    Young, Jamey D

    2014-12-01

    Identifying host cell metabolic phenotypes that promote high recombinant protein titer is a major goal of the biotech industry. (13)C metabolic flux analysis (MFA) provides a rigorous approach to quantify these metabolic phenotypes by applying isotope tracers to map the flow of carbon through intracellular metabolic pathways. Recent advances in tracer theory and measurements are enabling more information to be extracted from (13)C labeling experiments. Sustained development of publicly available software tools and standardization of experimental workflows is simultaneously encouraging increased adoption of (13)C MFA within the biotech research community. A number of recent (13)C MFA studies have identified increased citric acid cycle and pentose phosphate pathway fluxes as consistent markers of high recombinant protein expression, both in mammalian and microbial hosts. Further work is needed to determine whether redirecting flux into these pathways can effectively enhance protein titers while maintaining acceptable glycan profiles.

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

    Science.gov (United States)

    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.

  4. Analysis of ringing effects due to magnetic core materials in pulsed nuclear magnetic resonance circuits

    Energy Technology Data Exchange (ETDEWEB)

    Prabhu Gaunkar, N., E-mail: neelampg@iastate.edu; Bouda, N. R. Y.; Nlebedim, I. C.; Hadimani, R. L.; Mina, M.; Jiles, D. C. [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); Bulu, I.; Ganesan, K.; Song, Y. Q. [Schlumberger-Doll Research, Cambridge, Massachusetts 02139 (United States)

    2015-05-07

    This work presents investigations and detailed analysis of ringing in a non-resonant pulsed nuclear magnetic resonance (NMR) circuit. Ringing is a commonly observed phenomenon in high power switching circuits. The oscillations described as ringing impede measurements in pulsed NMR systems. It is therefore desirable that those oscillations decay fast. It is often assumed that one of the causes behind ringing is the role of the magnetic core used in the antenna (acting as an inductive load). We will demonstrate that an LRC subcircuit is also set-up due to the inductive load and needs to be considered due to its parasitic effects. It is observed that the parasitics associated with the inductive load become important at certain frequencies. The output response can be related to the response of an under-damped circuit and to the magnetic core material. This research work demonstrates and discusses ways of controlling ringing by considering interrelationships between different contributing factors.

  5. Characterization and Comparison of Fast Pyrolysis Bio-oils from Pinewood, Rapeseed Cake, and Wheat Straw Using 13C NMR and Comprehensive GC × GC

    Science.gov (United States)

    2016-01-01

    Fast pyrolysis bio-oils are feasible energy carriers and a potential source of chemicals. Detailed characterization of bio-oils is essential to further develop its potential use. In this study, quantitative 13C nuclear magnetic resonance (13C NMR) combined with comprehensive two-dimensional gas chromatography (GC × GC) was used to characterize fast pyrolysis bio-oils originated from pinewood, wheat straw, and rapeseed cake. The combination of both techniques provided new information on the chemical composition of bio-oils for further upgrading. 13C NMR analysis indicated that pinewood-based bio-oil contained mostly methoxy/hydroxyl (≈30%) and carbohydrate (≈27%) carbons; wheat straw bio-oil showed to have high amount of alkyl (≈35%) and aromatic (≈30%) carbons, while rapeseed cake-based bio-oil had great portions of alkyl carbons (≈82%). More than 200 compounds were identified and quantified using GC × GC coupled to a flame ionization detector (FID) and a time of flight mass spectrometer (TOF-MS). Nonaromatics were the most abundant and comprised about 50% of the total mass of compounds identified and quantified via GC × GC. In addition, this analytical approach allowed the quantification of high value-added phenolic compounds, as well as of low molecular weight carboxylic acids and aldehydes, which exacerbate the unstable and corrosive character of the bio-oil. PMID:27668136

  6. Characterization of organic matter in sediment cores of the Todos os Santos Bay, Bahia, Brazil, by elemental analysis and 13C NMR.

    Science.gov (United States)

    Costa, A B; Novotny, E H; Bloise, A C; de Azevedo, E R; Bonagamba, T J; Zucchi, M R; Santos, V L C S; Azevedo, A E G

    2011-08-01

    The impact of human activity on the sediments of Todos os Santos Bay in Brazil was evaluated by elemental analysis and 13C Nuclear Magnetic Resonance (13C NMR). This article reports a study of six sediment cores collected at different depths and regions of Todos os Santos Bay. The elemental profiles of cores collected on the eastern side of Frades Island suggest an abrupt change in the sedimentation regime. Autoregressive Integrated Moving Average (ARIMA) analysis corroborates this result. The range of depths of the cores corresponds to about 50 years ago, coinciding with the implantation of major onshore industrial projects in the region. Principal Component Analysis of the 13C NMR spectra clearly differentiates sediment samples closer to the Subaé estuary, which have high contents of terrestrial organic matter, from those closer to a local oil refinery. The results presented in this article illustrate several important aspects of environmental impact of human activity on this bay. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Characterization and Comparison of Fast Pyrolysis Bio-oils from Pinewood, Rapeseed Cake, and Wheat Straw Using (13)C NMR and Comprehensive GC × GC.

    Science.gov (United States)

    Negahdar, Leila; Gonzalez-Quiroga, Arturo; Otyuskaya, Daria; Toraman, Hilal E; Liu, Li; Jastrzebski, Johann T B H; Van Geem, Kevin M; Marin, Guy B; Thybaut, Joris W; Weckhuysen, Bert M

    2016-09-06

    Fast pyrolysis bio-oils are feasible energy carriers and a potential source of chemicals. Detailed characterization of bio-oils is essential to further develop its potential use. In this study, quantitative (13)C nuclear magnetic resonance ((13)C NMR) combined with comprehensive two-dimensional gas chromatography (GC × GC) was used to characterize fast pyrolysis bio-oils originated from pinewood, wheat straw, and rapeseed cake. The combination of both techniques provided new information on the chemical composition of bio-oils for further upgrading. (13)C NMR analysis indicated that pinewood-based bio-oil contained mostly methoxy/hydroxyl (≈30%) and carbohydrate (≈27%) carbons; wheat straw bio-oil showed to have high amount of alkyl (≈35%) and aromatic (≈30%) carbons, while rapeseed cake-based bio-oil had great portions of alkyl carbons (≈82%). More than 200 compounds were identified and quantified using GC × GC coupled to a flame ionization detector (FID) and a time of flight mass spectrometer (TOF-MS). Nonaromatics were the most abundant and comprised about 50% of the total mass of compounds identified and quantified via GC × GC. In addition, this analytical approach allowed the quantification of high value-added phenolic compounds, as well as of low molecular weight carboxylic acids and aldehydes, which exacerbate the unstable and corrosive character of the bio-oil.

  8. Rotor Design for High Pressure Magic Angle Spinning Nuclear Magnetic Resonance

    Energy Technology Data Exchange (ETDEWEB)

    Turcu, Romulus VF; Hoyt, David W.; Rosso, Kevin M.; Sears, Jesse A.; Loring, John S.; Felmy, Andrew R.; Hu, Jian Z.

    2013-01-01

    High pressure magic angle spinning (MAS) nuclear magnetic resonance (NMR) with a sample spinning rate exceeding 2.1 kHz and pressure greater than 165 bar has never been realized. In this work, a new sample cell design is reported, suitable for constructing cells of different sizes. Using a 7.5 mm high pressure MAS rotor as an example, internal pressure as high as 200 bar at a sample spinning rate of 6 kHz is achieved. The new high pressure MAS rotor is re-usable and compatible with most commercial NMR set-ups, exhibiting low 1H and 13C NMR background and offering maximal NMR sensitivity. As an example of its many possible applications, this new capability is applied to determine reaction products associated with the carbonation reaction of a natural mineral, antigorite ((Mg,Fe2+)3Si2O5(OH)4), in contact with liquid water in water-saturated supercritical CO2 (scCO2) at 150 bar and 50 deg C. This mineral is relevant to the deep geologic disposal of CO2, but its iron content results in too many sample spinning sidebands at low spinning rate. Hence, this chemical system is a good case study to demonstrate the utility of the higher sample spinning rates that can be achieved by our new rotor design. We expect this new capability will be useful for exploring solid-state, including interfacial, chemistry at new levels of high-pressure in a wide variety of fields.

  9. Rotor design for high pressure magic angle spinning nuclear magnetic resonance

    Science.gov (United States)

    Turcu, Romulus V. F.; Hoyt, David W.; Rosso, Kevin M.; Sears, Jesse A.; Loring, John S.; Felmy, Andrew R.; Hu, Jian Zhi

    2013-01-01

    High pressure magic angle spinning (MAS) nuclear magnetic resonance (NMR) with a sample spinning rate exceeding 2.1 kHz and pressure greater than 165 bar has never been realized. In this work, a new sample cell design is reported, suitable for constructing cells of different sizes. Using a 7.5 mm high pressure MAS rotor as an example, internal pressure as high as 200 bar at a sample spinning rate of 6 kHz is achieved. The new high pressure MAS rotor is re-usable and compatible with most commercial NMR set-ups, exhibiting low 1H and 13C NMR background and offering maximal NMR sensitivity. As an example of its many possible applications, this new capability is applied to determine reaction products associated with the carbonation reaction of a natural mineral, antigorite ((Mg,Fe2+)3Si2O5(OH)4), in contact with liquid water in water-saturated supercritical CO2 (scCO2) at 150 bar and 50 °C. This mineral is relevant to the deep geologic disposal of CO2, but its iron content results in too many sample spinning sidebands at low spinning rate. Hence, this chemical system is a good case study to demonstrate the utility of the higher sample spinning rates that can be achieved by our new rotor design. We expect this new capability will be useful for exploring solid-state, including interfacial, chemistry at new levels of high-pressure in a wide variety of fields.

  10. Experimental 25Mg and 13C NMR and Computational Modeling Studies of Amorphous Mg-Ca Carbonates

    Science.gov (United States)

    Singer, J. W.; Yazaydin, A. O.; Kirkpatrick, R. J.; Saharay, M.; Bowers, G. M.

    2012-12-01

    Nuclear magnetic resonance (NMR) spectroscopy of synthetic Mg-Ca amorphous carbonates (AMC-ACC) provides direct, element specific structural information about these complicated phases. The 13C, 25Mg, and 43Ca resonances are typically broad and span the chemical shift ranges of all the crystalline polymorphs in the Ca-Mg-CO3-H2O system. In a fashion similar to our previous analysis of 43Ca NMR results for ACC,1 here we integrate new experimental 13C and 25Mg spectra obtained at 20T for samples with Mg/(Ca+Mg) ratios from x=0 to x=1 with quantum chemical calculations of the NMR parameters of the crystalline phases using CASTEP calculations, simulations of the spectra using the SIMPSON software, and classical molecular dynamics calculations. XRD and 13C NMR results are in general agreement with the one-phase/two-phase model of ACC-AMC derived from thermochemical work by others.2 13C-NMR spectra of amorphous materials having intermediate compositions can not be completely fit by mechanical mixing of ACC and AMC end members—requiring a degree of Ca/Mg solid solution. Amorphous samples in two-phase region crystallize to assemblages of dolomite-like (x~0.5) and hydromagnesite-like (x~1) defective structures, but we also observe aragonite co-nucleation in the presence of excess water, indicative of a more complex evolution. While 43Ca NMR of X-ray amorphous materials shows featureless, symmetric, Gaussian line shapes, the large quadrupole moment of 25Mg gives rise to superposition of several quadrupolar line shapes representing different local structural environments. Singularities of static Mg spectra are best explained by local environments similar to nequehonite, hydromagnesite, and landsfordite. The spectra can not exclude minor contributions from anhydrous phases dolomite, huntite, and magnesite. Additional sites having very large quadrupolar coupling and/or site asymmetry are not explained by any known reference phases. CITATIONS (1) Singer, J. W.; Yazaydin, A. O

  11. Multinuclear solid-state nuclear magnetic resonance of inorganic materials

    CERN Document Server

    MacKenzie, Kenneth J D

    2002-01-01

    Techniques of solid state nuclear magnetic resonance (NMR) spectroscopy are constantly being extended to a more diverse range of materials, pressing into service an ever-expanding range of nuclides including some previously considered too intractable to provide usable results. At the same time, new developments in both hardware and software are being introduced and refined. This book covers the most important of these new developments. With sections addressed to non-specialist researchers (providing accessible answers to the most common questions about the theory and practice of NMR asked by novices) as well as a more specialised and up-to-date treatment of the most important areas of inorganic materials research to which NMR has application, this book should be useful to NMR users whatever their level of expertise and whatever inorganic materials they wish to study.

  12. Applications of nuclear magnetic resonance imaging in process engineering

    Science.gov (United States)

    Gladden, Lynn F.; Alexander, Paul

    1996-03-01

    During the past decade, the application of nuclear magnetic resonance (NMR) imaging techniques to problems of relevance to the process industries has been identified. The particular strengths of NMR techniques are their ability to distinguish between different chemical species and to yield information simultaneously on the structure, concentration distribution and flow processes occurring within a given process unit. In this paper, examples of specific applications in the areas of materials and food processing, transport in reactors and two-phase flow are discussed. One specific study, that of the internal structure of a packed column, is considered in detail. This example is reported to illustrate the extent of new, quantitative information of generic importance to many processing operations that can be obtained using NMR imaging in combination with image analysis.

  13. Nuclear Magnetic Resonance Study of Nanoscale Ionic Materials

    KAUST Repository

    Oommen, Joanna Mary

    2010-08-13

    Nanoscale ionic materials (NIMs) are a new class of nanomaterials that exhibit interesting properties including negligible vapor pressures and tunable physical states, among others. In this study, we analyzed the temperature-wise performance of NIMs using nuclear magnetic resonance (NMR) spectroscopy. NIMs are relatively stable over a temperature range from 300 to 383 K, rendering them usable in high temperature applications. We confirmed the presence of covalent bonds between the SiO2 core and the sulfonate group and determined relative concentrations of aromatic and aliphatic hydrocarbons. These findings serve as first hand proof-of-concept for the usefulness of NMR analyses in further studies on the diffusive properties of NIMs. © 2010 The Electrochemical Society.

  14. In vivo nuclear magnetic resonance metabolite profiling in plant seeds.

    Science.gov (United States)

    Terskikh, Victor; Kermode, Allison R

    2011-01-01

    Nuclear magnetic resonance (NMR) spectroscopy has been successfully applied to profile a variety of primary and secondary metabolites in whole intact plant seeds in vivo. The nondestructive nature of NMR spectroscopy allows direct metabolic studies to be performed on the same seed throughout a given physio-logical process or key lifecycle transition, such as dormancy breakage, germination, and early postgerminative growth. Multinuclear NMR is capable of evaluating seed quality by assessing nondestructively nutrient reserves and seed protectants at seed maturity and to further monitor reserve mobilization following germination, which is critical for seedling emergence. In this chapter, we illustrate the use of several in vivo NMR techniques for metabolite profiling in seeds. Importantly, some of these methods have potential for the screening of single seeds or seed populations to identify seedlots with compromised viability either due to developmental problems or as a result of deterioration during prolonged storage.

  15. Nuclear magnetic resonance tomography of the cervical canal

    Energy Technology Data Exchange (ETDEWEB)

    Terwey, B.; Koschorek, F.; Jensen, H.P.

    1985-12-01

    170 patients with suspected lesions of the cervical part of the medulla were examined using nuclear magnetic resonance (NMR) tomography. 27 cases revealed no pathological changes in the regions of the cervical medulla, the cervical canal and of the cervical spine. 143 cases produced pathological findings whose diagnoses determined therapeutical approach. Verified pathological changes comprised anomalies of the cranio-cervical junction like basilar impression and Arnold-Chiari malformation, various types of cavity formation in the cervical medulla (syringomyelia, hydromyelia), demyelinization processes, intramedullary and extramedullary tumours, intervertebral disk degeneration processes, dislocation of intervertebral disks and spondylophytes with spinal stenoses. Sagittal sections in different functional positions allowed to demonstrate the biomechanical effects of extramedullary masses on the cervical medulla. However, proven tumours could not be differentiated successfully using histological methods. Nevertheless, NMR tomography will replace invasive methods like conventional cervical myelography and CT myelography in diagnostic clarification of diseases of the cervical medulla.

  16. Nuclear magnetic resonance spectroscopy of single subnanoliter ova

    CERN Document Server

    Grisi, Marco; Guidetti, Roberto; Harris, Nicola; Boero, Giovanni

    2015-01-01

    Nuclear magnetic resonance (NMR) spectroscopy is, in principle, a promising candidate to study the intracellular chemistry of single microscopic living entities. However, due to sensitivity limitations, NMR experiments were reported only on very few and relatively large single cells down to a minimum volume of 10 nl. Here we show NMR spectroscopy of single ova at volume scales (0.1 and 0.5 nl) where life development begins for a broad variety of animals, humans included. We demonstrate that the sensitivity achieved by miniaturized inductive NMR probes (few pmol of 1H nuclei in some hours at 7 T) is sufficient to observe chemical heterogeneities among subnanoliter ova of tardigrades. Such sensitivities should allow to non-invasively monitor variations of concentrated intracellular compounds, such as glutathione, in single mammalian zygotes.

  17. Diffusion Pore Imaging by Hyperpolarized Xenon-129 Nuclear Magnetic Resonance

    CERN Document Server

    Kuder, Tristan Anselm; Windschuh, Johannes; Laun, Frederik Bernd

    2012-01-01

    Nuclear magnetic resonance (NMR) diffusion measurements are widely used to derive parameters indirectly related to the microstructure of biological tissues and porous media. However, a direct imaging of cell or pore shapes and sizes would be of high interest. For a long time, determining pore shapes by NMR diffusion acquisitions seemed impossible, because the necessary phase information could not be preserved. Here we demonstrate experimentally using the measurement technique which we have recently proposed theoretically that the shape of arbitrary closed pores can be imaged by diffusion acquisitions, which yield the phase information. For this purpose, we use hyperpolarized xenon gas in well-defined geometries. The signal can be collected from the whole sample which mainly eliminates the problem of vanishing signal at increasing resolution of conventional NMR imaging. This could be used to non-invasively gain structural information inaccessible so far such as pore or cell shapes, cell density or axon integri...

  18. Effect of a strong magnetic field on the energy yield of nuclear reactions in dense nuclear matter

    Energy Technology Data Exchange (ETDEWEB)

    Sekerzhitskii, V.S. [Pushkin Pedagogical Institute, Brest (Belarus)

    1995-01-01

    According to modern concepts, the electron-neutron-nuclear (Aen) phase of dense highly degenerate matter can be realized in the shells of neutron stars. This phase has relatively stable and absolutely stable states of thermodynamic equilibrium. Strong magnetic fields can exist in neutron stars. For this reason, analysis of their effect on the characteristics of the Aen phase is of great interest. It is specially important to study the influence of strong magnetic fields on the energy yield of nuclear reactions in dense nuclear matter because the transition to the absolute equilibrium state proceeds through these reactions.

  19. Low-frequency nuclear magnetic resonance and nuclear quadrupole resonance spectrometer based on a dc superconducting quantum interference device

    Science.gov (United States)

    Fan, N. Q.; Clarke, John

    1991-06-01

    A sensitive spectrometer, based on a dc superconducting quantum interference device, for the direct detection of low-frequency pulsed nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR), is described. The frequency response extends from about 10 to 200 kHz, and the recovery time after the magnetic pulse is removed is typically 50 μs. As examples, NMR spectra are shown from Pt and Cu metal powders in a magnetic field of 6 mT, and NQR spectra are shown from 2D in a tunneling methyl group and 14N in NH4ClO4.

  20. A simplified 13C-Urea breath test (13C-UBT) in the diagnosis of Helicobacter pylori (HP) infection

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, T.; Bartholomeusz, F.D. L.; Bellon, M.S.; Chatterton, B.E. [Royal Adelaide Hospital, Adelaide. SA (Australia). Department of Nuclear Medicine

    1998-06-01

    Full text: The Urea Breath Test (UBT) is an accurate, noninvasive means of assessing the presence of Helicobacter pylori in the stomach. Two tests are currently available, using 13C- and 14C-labelled urea, respectively. 13C is a nonradioactive isotope, unlike 14C, but the 13C-UBT is technically more challenging. The aim of this study was to determine the accuracy of a simplified 13C-UBT with no test meal, using the 14C-UBT as the previously validated standard. 76 studies were performed on 72 patients; 4 patients performed the test twice. 28 patients were female, 44 male. The mean age was 51.1 years (range 23-86 years). 42 patients presented for post-eradication follow up, and 30 for initial diagnosis. All subjects underwent a 14C-UBT with a 15 minute sample. The 13C-UBT was then performed without a test meal and the breath samples obtained at baseline and 20 minutes. Of the 14C-UBT studies, 27 were positive, ranging from 1372 to 10,987 DPM (Normal <1000 DPM), and 49 were negative, range 177-946 DPM. 26 of the 13C-UBT studies were positive, with a Delta value ranging from 4.29-47.89 (Normal: Delta <3.5), and 50 were negative, range -0.20-2.80. There were 1 false-positive and 2 false-negative 13-UBT studies. This yielded a sensitivity of 92.6% and specificity of 98.0% for the simplified 13C-UBT. From these results we conclude that the simplified 13C-UBT is an accurate means of detecting the presence of Helicobacter pylori within the stomach

  1. Saturation properties of nuclear matter in the presence of strong magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Rezaei, Z. [Shiraz University, Department of Physics and Biruni Observatory, Shiraz (Iran, Islamic Republic of); Bordbar, G.H. [Shiraz University, Department of Physics and Biruni Observatory, Shiraz (Iran, Islamic Republic of); Center for Excellence in Astronomy and Astrophysics (CEAA-RIAAM)-Maragha, P.O. Box 55134-441, Maragha (Iran, Islamic Republic of)

    2016-05-15

    Different saturation properties of cold symmetric nuclear matter in strong magnetic field have been considered. We have seen that for magnetic fields about B>3 x 10{sup 17} G, for both cases with and without nucleon anomalous magnetic moments, the saturation density and saturation energy grow by increasing the magnetic field. It is indicated that the magnetic susceptibility of symmetric nuclear matter becomes negative showing the diamagnetic response especially at B<3 x 10{sup 17} G. We have found that for the nuclear matter, the magnitude of orbital magnetization reaches higher values comparing to the spin magnetization. Our results for the incompressibility show that at high enough magnetic fields, i.e. B>3 x 10{sup 17} G, the softening of the equation of state caused by Landau quantization is overwhelmed by stiffening due to the magnetization of nuclear matter. We have shown that the effects of strong magnetic field on nuclear matter may affect the constraints on the equation of state of symmetric nuclear matter obtained by applying the experimental observables. (orig.)

  2. Nuclear magnetic resonance in atomic-scale superconductor/magnet multilayered systems

    CERN Document Server

    Kanegae, Y

    2003-01-01

    We investigate the nuclear spin-lattice relaxation rate (T sub 1 T) sup - sup 1 in atomic-scale superconductor/magnet multilayered systems and discuss the discrepancy between two recent (T sub 1 T) sup - sup 1 experiments on Ru in RuSr sub 2 YCu sub 2 O sub 8. When the magnetic layers is are in the antiferromagnetic state, (T sub 1 T) sup - sup 1 in the magnetic layers is shown to decrease with decreasing due to the excitation gap associated with the magnetic ordering. The proximity effect of superconductivity on (T sub 1 T) sup - sup 1 in the magnetic layer is negligibly small. Our result indicates that the temperature dependence of (T sub 1 T) sup - sup 1 on Ru in RuSr sub 2 YCu sub 2 O sub 8 likely originates from the antiferromagnetism in the RuO sub 2 layers, but not from the superconductivity in the CuO sub 2 layers. (author)

  3. High temperature spin dynamics in linear magnetic chains, molecular rings, and segments by nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Adelnia, Fatemeh; Lascialfari, Alessandro [Dipartimento di Fisica, Università degli Studi di Milano and INSTM, Milano (Italy); Dipartimento di Fisica, Università degli Studi di Pavia and INSTM, Pavia (Italy); Mariani, Manuel [Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna (Italy); Ammannato, Luca; Caneschi, Andrea; Rovai, Donella [Dipartimento di Chimica, Università degli Studi di Firenze and INSTM, Firenze (Italy); Winpenny, Richard; Timco, Grigore [School of Chemistry, The University of Manchester, Manchester (United Kingdom); Corti, Maurizio, E-mail: maurizio.corti@unipv.it; Borsa, Ferdinando [Dipartimento di Fisica, Università degli Studi di Pavia and INSTM, Pavia (Italy)

    2015-05-07

    We present the room temperature proton nuclear magnetic resonance (NMR) nuclear spin-lattice relaxation rate (NSLR) results in two 1D spin chains: the Heisenberg antiferromagnetic (AFM) Eu(hfac){sub 3}NITEt and the magnetically frustrated Gd(hfac){sub 3}NITEt. The NSLR as a function of external magnetic field can be interpreted very well in terms of high temperature spin dynamics dominated by a long time persistence of the decay of the two-spin correlation function due to the conservation of the total spin value for isotropic Heisenberg chains. The high temperature spin dynamics are also investigated in Heisenberg AFM molecular rings. In both Cr{sub 8} closed ring and in Cr{sub 7}Cd and Cr{sub 8}Zn open rings, i.e., model systems for a finite spin segment, an enhancement of the low frequency spectral density is found consistent with spin diffusion but the high cut-off frequency due to intermolecular anisotropic interactions prevents a detailed analysis of the spin diffusion regime.

  4. Rotatable Small Permanent Magnet Array for Ultra-Low Field Nuclear Magnetic Resonance Instrumentation: A Concept Study.

    Directory of Open Access Journals (Sweden)

    Michael W Vogel

    Full Text Available We studied the feasibility of generating the variable magnetic fields required for ultra-low field nuclear magnetic resonance relaxometry with dynamically adjustable permanent magnets. Our motivation was to substitute traditional electromagnets by distributed permanent magnets, increasing system portability.The finite element method (COMSOL® was employed for the numerical study of a small permanent magnet array to calculate achievable magnetic field strength, homogeneity, switching time and magnetic forces. A manually operated prototype was simulated and constructed to validate the numerical approach and to verify the generated magnetic field.A concentric small permanent magnet array can be used to generate strong sample pre-polarisation and variable measurement fields for ultra-low field relaxometry via simple prescribed magnet rotations. Using the array, it is possible to achieve a pre-polarisation field strength above 100 mT and variable measurement fields ranging from 20-50 μT with 200 ppm absolute field homogeneity within a field-of-view of 5 x 5 x 5 cubic centimetres.A dynamic small permanent magnet array can generate multiple highly homogeneous magnetic fields required in ultra-low field nuclear magnetic resonance (NMR and magnetic resonance imaging (MRI instruments. This design can significantly reduce the volume and energy requirements of traditional systems based on electromagnets, improving portability considerably.

  5. A scientific workflow framework for (13)C metabolic flux analysis.

    Science.gov (United States)

    Dalman, Tolga; Wiechert, Wolfgang; Nöh, Katharina

    2016-08-20

    Metabolic flux analysis (MFA) with (13)C labeling data is a high-precision technique to quantify intracellular reaction rates (fluxes). One of the major challenges of (13)C MFA is the interactivity of the computational workflow according to which the fluxes are determined from the input data (metabolic network model, labeling data, and physiological rates). Here, the workflow assembly is inevitably determined by the scientist who has to consider interacting biological, experimental, and computational aspects. Decision-making is context dependent and requires expertise, rendering an automated evaluation process hardly possible. Here, we present a scientific workflow framework (SWF) for creating, executing, and controlling on demand (13)C MFA workflows. (13)C MFA-specific tools and libraries, such as the high-performance simulation toolbox 13CFLUX2, are wrapped as web services and thereby integrated into a service-oriented architecture. Besides workflow steering, the SWF features transparent provenance collection and enables full flexibility for ad hoc scripting solutions. To handle compute-intensive tasks, cloud computing is supported. We demonstrate how the challenges posed by (13)C MFA workflows can be solved with our approach on the basis of two proof-of-concept use cases.

  6. 13C-based metabolic flux analysis: fundamentals and practice.

    Science.gov (United States)

    Yang, Tae Hoon

    2013-01-01

    Isotope-based metabolic flux analysis is one of the emerging technologies applied to system level metabolic phenotype characterization in metabolic engineering. Among the developed approaches, (13)C-based metabolic flux analysis has been established as a standard tool and has been widely applied to quantitative pathway characterization of diverse biological systems. To implement (13)C-based metabolic flux analysis in practice, comprehending the underlying mathematical and computational modeling fundamentals is of importance along with carefully conducted experiments and analytical measurements. Such knowledge is also crucial when designing (13)C-labeling experiments and properly acquiring key data sets essential for in vivo flux analysis implementation. In this regard, the modeling fundamentals of (13)C-labeling systems and analytical data processing are the main topics we will deal with in this chapter. Along with this, the relevant numerical optimization techniques are addressed to help implementation of the entire computational procedures aiming at (13)C-based metabolic flux analysis in vivo.

  7. Synthesis and applications of {sup 13}C glycerol

    Energy Technology Data Exchange (ETDEWEB)

    Stocking, E.; Khalsa, O.; Martinez, R.A.; Silks, L.A. III [Los Alamos National Laboratory, NM (United States)

    1994-12-01

    Due in part to the use of labeled glycerol for the {sup 13}C enrichment of biomolecules, we are currently developing new synthetic routes to various isotopomers of glycerol. Judging from our experience, traditional methods of glycerol synthesis are not easily adapted for isotopic enrichment and/or have poor overall yields (12 to 15%). Furthermore, the use of glycerol for enrichment can be prohibitively expensive and its availability is limited by the level of demand. We are presently developing a short de novo synthesis of glycerol from carbon dioxide ({approximately}53% overall yield for four steps) and are examining the feasibility of synthesizing site-specific {sup 13}C-labeled glycerol and dihydroxyacetone (DHA) from labeled methanol and carbon dioxide. One application of {sup 13}C glycerol we have examined is enzymatic conversion of glycerol to glyceraldehyde-3-monophosphate or dihydroxyacetone monophosphate (DHAP) with yields ranging from 25 to 50% (as determined by NMR spectroscopy). We are also pursuing the chemical conversion of {sup 13}C-labeled DHA to DHAP. We are especially interested in {sup 13}C-labeled DHAP because we are investigating its use as a chemo-enzymatic precursor for both labeled 2-deoxyribose and 2-deoxyribonucleic acids.

  8. Solid State Nuclear Magnetic Resonance Investigation of Polymer Backbone Dynamics in Poly(Ethylene Oxide) Based Lithium and Sodium Polyether-ester-sulfonate Ionomers

    Energy Technology Data Exchange (ETDEWEB)

    Roach, David J.; Dou, Shichen; Colby, Ralph H.; Mueller, Karl T.

    2013-01-01

    Polymer backbone dynamics of single ion conducting poly(ethylene oxide) (PEO)-based ionomer samples with low glass transition temperatures (Tg) have been investigated using solid-state nuclear magnetic resonance (NMR). Experiments detecting 13C with 1H decoupling under magic angle spinning (MAS) conditions identified the different components of the polymer backbone (PEO spacer and isophthalate groups) and their relative mobilities for a suite of lithium- and sodium-containing ionomer samples with varying cation contents. Variable temperature (203-373 K) 1H-13C cross-polarization MAS (CP-MAS) experiments also provided qualitative assessment of the differences in the motions of the polymer backbone components as a function of cation content and identity. Each of the main backbone components exhibit distinct motions, following the trends expected for motional characteristics based on earlier Quasi Elastic Neutron Scattering and 1H spin-lattice relaxation rate measurements. Previous 1H and 7Li spin-lattice relaxation measurements focused on both the polymer backbone and cation motion on the nanosecond timescale. The studies presented here assess the slower timescale motion of the polymer backbone allowing for a more comprehensive understanding of the polymer dynamics. The temperature dependences of 13C linewidths were used to both qualitatively and quantitatively examine the effects of cation content and identity on PEO spacer mobility. Variable contact time 1H-13C CP-MAS experiments were used to further assess the motions of the polymer backbone on the microsecond timescale. The motion of the PEO spacer, reported via the rate of magnetization transfer from 1H to 13C nuclei, becomes similar for T ≳ 1.1 Tg in all ionic samples, indicating that at similar elevated reduced temperatures the motions of the polymer backbones on the microsecond timescale become insensitive to ion interactions. These results present an improved picture, beyond those of previous findings, for

  9. Mineral Carbonation in Wet Supercritical CO2: An in situ High-Pressure Magic Angle Spinning Nuclear Magnetic Resonance Study

    Science.gov (United States)

    Turcu, R. V.; Hoyt, D. H.; Sears, J. A.; Rosso, K. M.; Felmy, A. R.; Hu, J. Z.

    2011-12-01

    Understanding the mechanisms and kinetics of mineral carbonation reactions relevant to sequestering carbon dioxide as a supercritical fluid (scCO2) in geologic formations is crucial for accurately predicting long-term storage risks. In situ probes that provide molecular-level information at geologically relevant temperatures and pressures are highly desirable and challenging to develop. Magic angle spinning nuclear magnetic resonance (MAS NMR) is a powerful tool for obtaining detailed molecular structure and dynamics information of a system regardless whether the system is in a solid, a liquid, a gaseous, a supercritical state, or a mixture thereof. However, MAS NMR under scCO2 conditions has never been realized due to the tremendous technical difficulties of achieving and maintaining high pressure within a fast spinning MAS sample rotor. In this work, we report development of a unique high pressure MAS NMR capability capable of handling fluid pressure exceeding 170 bars and temperatures up to 80°C, and its application to mineral carbonation in scCO2 under geologically relevant temperatures and pressures. Mineral carbonation reactions of the magnesium silicate mineral forsterite and the magnesium hydroxide brucite reacted with scCO2 (up to 170 bar) and containing variable content of H2O (at, below, and above saturation in scCO2) were investigated at 50 to 70°C. In situ 13C MAS NMR spectra show peaks corresponding to the reactants, intermediates, and the magnesium carbonation products in a single spectrum. For example, Figure 1 shows the reaction dynamics, i.e., the formation and conversion of reaction intermediates, i.e., HCO3- and nesquehonite, to magnesite as a function of time at 70°C. This capability offers a significant advantage over traditional ex situ 13C MAS experiments on similar systems, where, for example, CO2 and HCO3- are not directly observable.

  10. Nuclear forward scattering of synchrotron radiation in pulsed high magnetic fields.

    Science.gov (United States)

    Strohm, C; Van der Linden, P; Rüffer, R

    2010-02-26

    We report the demonstration of nuclear forward scattering of synchrotron radiation from 57Fe in ferromagnetic alpha iron in pulsed high magnetic fields up to 30 T. The observed magnetic hyperfine field follows the calculated high field bulk magnetization within 1%, establishing the technique as a precise tool for the study of magnetic solids in very high magnetic fields. To perform these experiments in pulsed fields, we have developed a detection scheme for fully time resolved nuclear forward scattering applicable to other pump probe experiments.

  11. Magnetic Moments of Octet Baryons in Hot and Dense Nuclear Matter

    CERN Document Server

    Singh, Harpreet; Dahiya, Harleen

    2016-01-01

    We have calculated the in-medium magnetic moments of octet baryons in the presence of hot and dense symmetric nuclear matter. Effective magnetic moments of baryons have been derived from medium modified quark masses within chiral SU(3) quark mean field model.Further, for better insight of medium modification of baryonic magnetic moments, we have considered the explicit contributions from the valence as well as sea quark effects. These effects have been successful in giving the description of baryonic magnetic moments in vacuum. The magnetic moments of baryons are found to vary significantly as a function of density of nuclear medium.

  12. Integrated Geophysical Measurements for Bioremediation Monitoring: Combining Spectral Induced Polarization, Nuclear Magnetic Resonance and Magnetic Methods

    Energy Technology Data Exchange (ETDEWEB)

    Keating, Kristina [Rutgers Univ., Newark, NJ (United States). Dept. of Earth and Environmental Sciences; Slater, Lee [Rutgers Univ., Newark, NJ (United States). Dept. of Earth and Environmental Sciences; Ntarlagiannis, Dimitris [Rutgers Univ., Newark, NJ (United States). Dept. of Earth and Environmental Sciences; Williams, Kenneth H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division

    2015-02-24

    This documents contains the final report for the project "Integrated Geophysical Measurements for Bioremediation Monitoring: Combining Spectral Induced Polarization, Nuclear Magnetic Resonance and Magnetic Methods" (DE-SC0007049) Executive Summary: Our research aimed to develop borehole measurement techniques capable of monitoring subsurface processes, such as changes in pore geometry and iron/sulfur geochemistry, associated with remediation of heavy metals and radionuclides. Previous work has demonstrated that geophysical method spectral induced polarization (SIP) can be used to assess subsurface contaminant remediation; however, SIP signals can be generated from multiple sources limiting their interpretation value. Integrating multiple geophysical methods, such as nuclear magnetic resonance (NMR) and magnetic susceptibility (MS), with SIP, could reduce the ambiguity of interpretation that might result from a single method. Our research efforts entails combining measurements from these methods, each sensitive to different mineral forms and/or mineral-fluid interfaces, providing better constraints on changes in subsurface biogeochemical processes and pore geometries significantly improving our understanding of processes impacting contaminant remediation. The Rifle Integrated Field Research Challenge (IFRC) site was used as a test location for our measurements. The Rifle IFRC site is located at a former uranium ore-processing facility in Rifle, Colorado. Leachate from spent mill tailings has resulted in residual uranium contamination of both groundwater and sediments within the local aquifer. Studies at the site include an ongoing acetate amendment strategy, native microbial populations are stimulated by introduction of carbon intended to alter redox conditions and immobilize uranium. To test the geophysical methods in the field, NMR and MS logging measurements were collected before, during, and after acetate amendment. Next, laboratory NMR, MS, and SIP measurements

  13. Magnetism and Superconductivity in Iron-based Superconductors as Probed by Nuclear Magnetic Resonance

    CERN Document Server

    Hammerath, Franziska

    2012-01-01

    Nuclear Magnetic Resonance (NMR) has been a fundamental player in the studies of superconducting materials for many decades. This local probe technique allows for the study of the static electronic properties as well as of the low energy excitations of the electrons in the normal and the superconducting state. On that account it has also been widely applied to Fe-based superconductors from the very beginning of their discovery in February 2008. This dissertation comprises some of these very first NMR results, reflecting the unconventional nature of superconductivity and its strong link to magnetism in the investigated compounds LaO1–xFxFeAs and LiFeAs.

  14. {sup 13}C relaxation in an RNA hairpin

    Energy Technology Data Exchange (ETDEWEB)

    King, G.C. [Univ. of South Wales, Kensington (Australia)]|[Rice Univ., Houston, TX (United States); Akratos, C. [Univ. of South Wales, Kensington (Australia); Xi, Z.; Michnica, M.J. [Rice Univ., Houston, TX (United States)

    1994-12-01

    This initial survey of {sup 13}C relaxation in the {triangle}TAR RNA element has generated a number of interesting results that should prove generally useful for future studies. The most readily comparable study in the literature monitored {sup 13}C relaxation of the methyl groups from unusual bases in tRNA{sup Phe}. The study, which used T{sub 1} and NOE data only, reported order parameters for the methyl group axis that ranged between 0.51 and 0.97-a range similar to that observed here. However, they reported a breakdown of the standard order parameter analysis at higher (118-MHz {sup 13}C) frequencies, which should serve to emphasize the need for a thorough exploration of suitable motional models.

  15. Noninvasive biomarkers for acute hepatotoxicity induced by 1,3-dichloro-2-propanol: hyperpolarized 13C dynamic MR spectroscopy.

    Science.gov (United States)

    Kim, Gwang-Won; Oh, Chang-Hyun; Kim, Jong-Choon; Yoon, Woong; Jeong, Yong-Yeon; Kim, Yun-Hyeon; Kim, Jae-Kyu; Park, Jin-Gyoon; Kang, Heoung-Keun; Jeong, Gwang-Woo

    2016-02-01

    The purpose of this study was to investigate the cellular metabolite change for acute hepatotoxicity induced by 1,3-dichloro-2-propanol (1,3-DCP) in rats and its correlations with the enzyme levels. In order to induce acute hepatotoxicity, a single subcutaneous injection of 1,3-DCP (80 mg/kg) was given to six male Sprague-Dawley rats. Hyperpolarized (13)C dynamic magnetic resonance spectroscopy (MRS) was performed on rat liver following injection of hyperpolarized [1-(13)C] pyruvate. The levels of serum aspartate am inotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) in the 1,3-DCP treated rats were significantly increased as compared with those in normal rats. In the dynamic (13)C MR spectra, the ratios of [1-(13)C] lactate to the total carbon and [1-(13)C] alanine to the total carbon in the 1,3-DCP treated rats were significantly increased, and there were positive correlations between cellular metabolic changes and enzyme levels. The levels of [1-(13)C] lactate and [1-(13)C] alanine are potentially considered as important biomarkers for the 1,3-DCP-induced acute hepatotoxicity.

  16. Nuclear magnetic resonance experiments with dc SQUID amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Heaney, M.B. (California Univ., Berkeley, CA (USA). Dept. of Physics Lawrence Berkeley Lab., CA (USA))

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting QUantum Interference Devices) with Nb/Al{sub 2}O{sub 3}/Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 {times} 10{sup 17} in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO{sub 3} crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies.

  17. Frequency and Spatial Selectivity in Nuclear Magnetic Resonance Spectroscopy.

    Science.gov (United States)

    Friedrich, Jan O.

    1988-12-01

    Available from UMI in association with The British Library. Requires signed TDF. The techniques presented in this thesis are concerned with the high resolution nuclear magnetic resonance spectra of liquids. A selective pulse, shaped according to the first half of a Gaussian curve, is developed; it gives a very narrow absorption-mode excitation profile. This characteristics is used in developing selective coherence transfer experiments in which an individual transition is irradiated by the selective pulse followed by irradiation with an intense non-selective pulse. By stepping the irradiation frequency of the selective pulse along in small increments, this experiment produces results similar to conventional two-dimensional homonuclear correlation spectroscopy. Such a method allows selected spectral regions of a conventional two-dimensional spectrum to be examined under higher resolution while avoiding the restrictions imposed by the sampling theorem. The technique is also extended to a third frequency dimension by irradiating two transitions simultaneously before applying a non-selective pulse which yields correlations between three coupled nuclei. The remainder of this thesis introduces a spatial localisation method based on a "straddle coil": two parallel coaxial surface coils, one on each side of the sample and supplied with radiofrequency pulses of opposite phase. This configuration can be used for spatial localisation experiments by applying a sequence of equal and opposite prepulses before acquiring the signal. The prepulses saturate the nuclear spins in all sample regions except the sensitive volume close to the median plane where the radiofrequency fields from the two coils cancel. Pulse sequences are proposed that are insensitive to radiofrequency offset over an appreciable range. The location of the sensitive volume can be tracked across the sample in the axial dimension by changing the ratio of the radiofrequency currents in the two coils.

  18. Nuclear magnetic resonance experiments with DC SQUID amplifiers

    Science.gov (United States)

    Heaney, M. B.

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting Quantum Interference Devices) with Nb/Al2O3/Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 x 10(exp 17) in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO3 crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies.

  19. Direct 13C NMR Detection in HPLC Hyphenation Mode

    DEFF Research Database (Denmark)

    Wubshet, Sileshi Gizachew; Johansen, Kenneth; Nyberg, Nils

    2012-01-01

    Solid phase extraction (SPE) was introduced as a crucial step in the HPLC-SPE-NMR technique to enable online analyte enrichment from which proton-detected NMR experiments on submicrogram amounts from complex mixtures were possible. However, the significance of direct-detected (13)C NMR experiments...... application of HPLC-SPE-NMR analysis using direct-detected (13)C NMR spectra. HPLC column loading, accumulative SPE trappings, and the effect of different elution solvents were evaluated and optimized. A column loading of approximately 600 mug of a prefractionated triterpenoid mixture, six trappings...

  20. Multi-exponential inversions of nuclear magnetic resonance relaxation signal

    Institute of Scientific and Technical Information of China (English)

    WANG; Weimin(

    2001-01-01

    [1]Kenyon, W. E. , Petrophysical principles of applications of NMR logging, The Log Analyst, 1997, March-April: 21-43.[2]Timur, A., Producible porosity and permeability of sandstone investigated through nuclear magnetic resonance principles,Journal of Petroleum Technology, 1969, 21: 775-786.[3]Chakrabarty, T. , Longo, J. , A new method for mineral quantification to aid in hydrocarbon exploration and exploitation,Journal of Canadian Petroleum Technology, 1997, 36(11 ): 15-21.[4]Kleinberg, R. L. , Vinegar, H. J. , NMR properties of reservoir fluids, The Log Analyst, 1996, November-December: 20-32.[5]Wahba, G. , Practical approximate solutions to linear operator equations when the data are noisy, SIAM. J. Numer. Anal. ,1977, 14(4): 651-667.[6]Butler, J. P. , Reeds, J. A. , Dawson, S. V. , Estimating solutions of first kind integral equations with nonnegative constraints and optimal smoothing, SIAM J. Numer. Anal. , 1981, 18(3): 381-397.[7]Munn, K. , Smith, D. M., A NMR technique for the analysis of pore structure: Numerical inversion of relaxation measurements, Journal of Colloid and Interface Science, 1987,19(1): 117-126.[8]Provencher, S. W., A constrained regularization method for inverting data represented by linear algebraic or integral equations, Computer Physics Communications, 1982, 27: 213-227.[9]Bergman, D. J., Dunn, K. J., Magnetic susceptibility contrasted fixed field gradient effects on the spin-echo amplitude in a periodic porous media with diffusion, Phys. Soc., 1995, 40: 695-702.[10]Wang Weimin, The basic experiment studies of NMR logging, Well Logging Technology, 1997, 21 (6): 385-392.

  1. Nuclear magnetic relaxation studies of semiconductor nanocrystals and solids

    Energy Technology Data Exchange (ETDEWEB)

    Sachleben, J. R. [Lawrence Berkeley Lab., CA (United States); California Univ., Berkeley, CA (United States). Dept. of Chemistry

    1993-09-01

    Semiconductor nanocrystals, small biomolecules, and {sup 13}C enriched solids were studied through the relaxation in NMR spectra. Surface structure of semiconductor nanocrystals (CdS) was deduced from high resolution {sup 1}H and {sup 13}C liquid state spectra of thiophenol ligands on the nanocrystal surfaces. The surface coverage by thiophenol was found to be low, being 5.6 and 26% for nanocrystal radii of 11.8 and 19.2 {angstrom}. Internal motion is estimated to be slow with a correlation time > 10{sup {minus}8} s{sup {minus}1}. The surface thiophenol ligands react to form a dithiophenol when the nanocrystals were subjected to O{sub 2} and ultraviolet. A method for measuring {sup 14}N-{sup 1}H J-couplings is demonstrated on pyridine and the peptide oxytocin; selective 2D T{sub 1} and T{sub 2} experiments are presented for measuring relaxation times in crowded spectra with overlapping peaks in 1D, but relaxation effects interfere. Possibility of carbon-carbon cross relaxation in {sup 13}C enriched solids is demonstrated by experiments on zinc acetate and L-alanine.

  2. Microphase structures and 13C NMR relaxation parameters in ultrahigh molecular weight polyethylene

    Institute of Scientific and Technical Information of China (English)

    朱清仁; 洪昆仑; 鲁非; 戚嵘嵘; 庞文民; 周贵恩; 宋名实

    1995-01-01

    The phase transformations in ultrahigh molecular weight polyethylene(UHMWPE)gel-filmsupon superdrawing have been studied by X-ray diffraction and high resolution solid state 13C NMR.Themorphological change and molecular motions in the crystalline phase,amorphous phase and interphase are dis-cussed according to the 13C nuclear relaxation time(T1c,T2cresults.A brief interpretation to the three orfour T1cvalues in the crystalline phase is presented.It is found that the component with the highest T1c(T1cα)plays a key role in the forming of ’Shish-Kebab’ microfibril which determines the sample strength andmodulus,namely,the greater the T1cα,the higher the modulus and strength of the drawn UHMWPEgel-film.These results support the ’Shish-Kebabs’ model in crystalline polymers.

  3. Nuclear magnetic resonance imaging of water content in the subsurface

    Energy Technology Data Exchange (ETDEWEB)

    J. Hendricks; T. Yao; A. Kearns

    1999-01-21

    Previous theoretical and experimental studies indicated that surface nuclear magnetic resonance (NMR) has the potential to provide cost-effective water content measurements in the subsurface and is a technology ripe for exploitation in practice. The objectives of this investigation are (a) to test the technique under a wide range of hydrogeological conditions and (b) to generalize existing NMR theories in order to correctly model NMR response from conductive ground and to assess properties of the inverse problem. Twenty-four sites with different hydrogeologic settings were selected in New Mexico and Colorado for testing. The greatest limitation of surface NMR technology appears to be the lack of understanding in which manner the NMR signal is influenced by soil-water factors such as pore size distribution, surface-to-volume ratio, paramagnetic ions dissolved in the ground water, and the presence of ferromagnetic minerals. Although the theoretical basis is found to be sound, several advances need to be made to make surface NMR a viable technology for hydrological investigations. There is a research need to investigate, under controlled laboratory conditions, how the complex factors of soil-water systems affect NMR relaxation times.

  4. Nuclear magnetic resonance studies of bovine γB-crystallin

    Science.gov (United States)

    Thurston, George; Mills, Jeffrey; Michel, Lea; Mathews, Kaylee; Zanet, John; Payan, Angel; van Nostrand, Keith; Kotlarchyk, Michael; Ross, David; Wahle, Christopher; Hamilton, John

    Anisotropy of shape and/or interactions play an important role in determining the properties of concentrated solutions of the eye lens protein, γB-crystallin, including its liquid-liquid phase transition. We are studying γB anisotropic interactions with use of nuclear magnetic resonance (NMR) concentration- and temperature-dependent chemical shift perturbations (CSPs). We analyze two-dimensional heteronuclear spin quantum coherence (HSQC) spectra on backbone nitrogen and attached hydrogen nuclei for CSPs, up to 3 percent volume fraction. Cumulative distribution functions of the CSPs show a concentration and temperature-dependent spread. Many peaks that are highly shifted with either concentration or temperature are close (i) crystal intermolecular contacts (ii) locations of cataractogenic point mutations of a homologous human protein, human γD-crystallin, and (iii) charged amino-acid residues. We also discuss the concentration- and temperature-dependence of NMR and quasielastic light scattering measurements of rotational and translational diffusion of γB crystallin in solution, affected by interprotein attractions. Supported by NIH EY018249.

  5. Two-dimensional nuclear magnetic resonance of quadrupolar systems

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shuanhu

    1997-09-17

    This dissertation describes two-dimensional nuclear magnetic resonance theory and experiments which have been developed to study quadruples in the solid state. The technique of multiple-quantum magic-angle spinning (MQMAS) is extensively reviewed and expanded upon in this thesis. Specifically, MQMAS is first compared with another technique, dynamic-angle spinning (DAS). The similarity between the two techniques allows us to extend much of the DAS work to the MQMAS case. Application of MQMAS to a series of aluminum containing materials is then presented. The superior resolution enhancement through MQMAS is exploited to detect the five- and six-coordinated aluminum in many aluminosilicate glasses. Combining the MQMAS method with other experiments, such as HETCOR, greatly expands the possibility of the use of MQMAS to study a large range of problems and is demonstrated in Chapter 5. Finally, the technique switching-angle spinning (SAS) is applied to quadrupolar nuclei to fully characterize a quadrupolar spin system in which all of the 8 NMR parameters are accurately determined. This dissertation is meant to demonstrate that with the combination of two-dimensional NMR concepts and new advanced spinning technologies, a series of multiple-dimensional NMR techniques can be designed to allow a detailed study of quadrupolar nuclei in the solid state.

  6. Membrane proteins structure and dynamics by nuclear magnetic resonance.

    Science.gov (United States)

    Maltsev, Sergey; Lorigan, Gary A

    2011-10-01

    Membrane proteins represent a challenging class of biological systems to study. They are extremely difficult to crystallize and in most cases they retain their structure and functions only in membrane environments. Therefore, commonly used diffraction methods fail to give detailed molecular structure and other approaches have to be utilized to obtain biologically relevant information. Nuclear magnetic resonance (NMR) spectroscopy, however, can provide powerful structural and dynamical constraints on these complicated systems. Solution- and solid-state NMR are powerful methods for investigating membrane proteins studies. In this work, we briefly review both solution and solid-state NMR techniques for membrane protein studies and illustrate the applications of these methods to elucidate proteins structure, conformation, topology, dynamics, and function. Recent advances in electronics, biological sample preparation, and spectral processing provided opportunities for complex biological systems, such as membrane proteins inside lipid vesicles, to be studied faster and with outstanding quality. New analysis methods therefore have emerged, that benefit from the combination of sample preparation and corresponding specific high-end NMR techniques, which give access to more structural and dynamic information.

  7. Advances in Nuclear Magnetic Resonance for Drug Discovery

    Science.gov (United States)

    Powers, Robert

    2010-01-01

    Background Drug discovery is a complex and unpredictable endeavor with a high failure rate. Current trends in the pharmaceutical industry have exasperated these challenges and are contributing to the dramatic decline in productivity observed over the last decade. The industrialization of science by forcing the drug discovery process to adhere to assembly-line protocols is imposing unnecessary restrictions, such as short project time-lines. Recent advances in nuclear magnetic resonance are responding to these self-imposed limitations and are providing opportunities to increase the success rate of drug discovery. Objective/Method A review of recent advancements in NMR technology that have the potential of significantly impacting and benefiting the drug discovery process will be presented. These include fast NMR data collection protocols and high-throughput protein structure determination, rapid protein-ligand co-structure determination, lead discovery using fragment-based NMR affinity screens, NMR metabolomics to monitor in vivo efficacy and toxicity for lead compounds, and the identification of new therapeutic targets through the functional annotation of proteins by FAST-NMR. Conclusion NMR is a critical component of the drug discovery process, where the versatility of the technique enables it to continually expand and evolve its role. NMR is expected to maintain this growth over the next decade with advancements in automation, speed of structure calculation, in-cell imaging techniques, and the expansion of NMR amenable targets. PMID:20333269

  8. Dynamic nuclear magnetic resonance field sensing with part-per-trillion resolution

    Science.gov (United States)

    Gross, Simon; Barmet, Christoph; Dietrich, Benjamin E.; Brunner, David O.; Schmid, Thomas; Pruessmann, Klaas P.

    2016-12-01

    High-field magnets of up to tens of teslas in strength advance applications in physics, chemistry and the life sciences. However, progress in generating such high fields has not been matched by corresponding advances in magnetic field measurement. Based mostly on nuclear magnetic resonance, dynamic high-field magnetometry is currently limited to resolutions in the nanotesla range. Here we report a concerted approach involving tailored materials, magnetostatics and detection electronics to enhance the resolution of nuclear magnetic resonance sensing by three orders of magnitude. The relative sensitivity thus achieved amounts to 1 part per trillion (10-12). To exemplify this capability we demonstrate the direct detection and relaxometry of nuclear polarization and real-time recording of dynamic susceptibility effects related to human heart function. Enhanced high-field magnetometry will generally permit a fresh look at magnetic phenomena that scale with field strength. It also promises to facilitate the development and operation of high-field magnets.

  9. Metabolic flux analysis using 13C peptide label measurements

    Science.gov (United States)

    13C metabolic flux analysis (MFA) has become the experimental method of choice to investigate cellular metabolism. MFA has established flux maps of central metabolism for dozens of microbes, cell cultures, and plant seeds. Steady-state MFA utilizes isotopic labeling measurements of amino acids obtai...

  10. Revisiting the metathesis of 13C-monolabeled ethane

    KAUST Repository

    Maury, Olivier

    2010-12-13

    The metathesis of 13C-monolabeled ethane leads to the parallel occurrence of degenerate and productive reactions, affording the statistical distribution of the various product isotopomers, which can be rationalized in terms of a mechanistic reaction scheme combining both processes. © 2010 American Chemical Society.

  11. δ13C-CH4 in ice core samples

    DEFF Research Database (Denmark)

    Sperlich, Peter

    Ice core records of δ13C-CH4 reflect the variability of CH4 biogeochemistry in response to climate change and show this system is far more complex than expected. The first part of this work is concerned with the development of analytical techniques that allow 1) precise referencing and 2) measure......Ice core records of δ13C-CH4 reflect the variability of CH4 biogeochemistry in response to climate change and show this system is far more complex than expected. The first part of this work is concerned with the development of analytical techniques that allow 1) precise referencing and 2......) measurements of δ13C-CH4 in ice core samples as is required when δ13C-CH4 records that are measured in several laboratories are merged for analysis. Both the referencing and measurement techniques have been compared to further laboratories which proofed the accuracy of the analytical systems. The second part...

  12. δ13C-CH4 in ice core samples

    DEFF Research Database (Denmark)

    Sperlich, Peter

    Ice core records of δ13C-CH4 reflect the variability of CH4 biogeochemistry in response to climate change and show this system is far more complex than expected. The first part of this work is concerned with the development of analytical techniques that allow 1) precise referencing and 2) measure......Ice core records of δ13C-CH4 reflect the variability of CH4 biogeochemistry in response to climate change and show this system is far more complex than expected. The first part of this work is concerned with the development of analytical techniques that allow 1) precise referencing and 2......) measurements of δ13C-CH4 in ice core samples as is required when δ13C-CH4 records that are measured in several laboratories are merged for analysis. Both the referencing and measurement techniques have been compared to further laboratories which proofed the accuracy of the analytical systems. The second part...

  13. Real-time detection of hepatic gluconeogenic and glycogenolytic states using hyperpolarized [2-13C]dihydroxyacetone.

    Science.gov (United States)

    Moreno, Karlos X; Satapati, Santhosh; DeBerardinis, Ralph J; Burgess, Shawn C; Malloy, Craig R; Merritt, Matthew E

    2014-12-26

    Glycogenolysis and gluconeogenesis are sensitive to nutritional state, and the net direction of flux is controlled by multiple enzymatic steps. This delicate balance in the liver is disrupted by a variety of pathological states including cancer and diabetes mellitus. Hyperpolarized carbon-13 magnetic resonance is a new metabolic imaging technique that can probe intermediary metabolism nondestructively. There are currently no methods to rapidly distinguish livers in a gluconeogenic from glycogenolytic state. Here we use the gluconeogenic precursor dihydroxyacetone (DHA) to deliver hyperpolarized carbon-13 to the perfused mouse liver. DHA enters gluconeogenesis at the level of the trioses. Perfusion conditions were designed to establish either a gluconeogenic or a glycogenolytic state. Unexpectedly, we found that [2-(13)C]DHA was metabolized within a few seconds to the common intermediates and end products of both glycolysis and gluconeogenesis under both conditions, including [2,5-(13)C]glucose, [2-(13)C]glycerol 3-phosphate, [2-(13)C]phosphoenolpyruvate (PEP), [2-(13)C]pyruvate, [2-(13)C]alanine, and [2-(13)C]lactate. [2-(13)C]Phosphoenolpyruvate, a key branch point in gluconeogenesis and glycolysis, was monitored in functioning tissue for the first time. Observation of [2-(13)C]PEP was not anticipated as the free energy difference between PEP and pyruvate is large. Pyruvate kinase is the only regulatory step of the common glycolytic-gluconeogenic pathway that appears to exert significant control over the kinetics of any metabolites of DHA. A ratio of glycolytic to gluconeogenic products distinguished the gluconeogenic from glycogenolytic state in these functioning livers.

  14. Application of 13C NMR spectroscopy to characterize organic chemical components of decomposing coarse woody debris from different climatic regions

    Directory of Open Access Journals (Sweden)

    Takuya Hishinuma

    2015-04-01

    Full Text Available Solid-state 13C nuclear magnetic resonance (NMR spectroscopy was applied to coarse woody debris (CWD in different stages of decomposition and collected from forest floor of a subtropical, a cool temperate, and a subalpine forest in Japan. The purpose was to test its applicability to characterize organic chemical composition of CWD of broad-leaved and coniferous trees from different climatic conditions. O-alkyl-C, mainly representing carbohydrates, was the predominant component of CWD at the three sites, accounting for 43.5-58.1% of the NMR spectra. Generally, the relative area under the signals for aromatic-C and phenolic-C, mainly representing lignin, increased, whereas the relative area for O-alkyl-C decreased, as the decay class advanced. The relative area under NMR chemical shift regions was significantly correlated with the chemical properties examined with proximate analyses. That is, O-alkyl-C and di-O-alkyl-C NMR signal areas were positively correlated with the volumetric density of CWD and the content of total carbohydrates. Methoxyl-C, aromatic-C, phenolic-C, carboxyl-C, and carbonyl-C were positively correlated with the contents of acid-unhydrolyzable residues (lignin, tannins, and cutin and nitrogen. Lignin-C calculated from NMR signals increased, and polysaccharide-C decreased, with the decay class of CWD at the three study sites. A review of previous studies on 13C NMR spectroscopy for decomposing CWD suggested further needs of its application to broad-leaved trees from tropical and subtropical regions.

  15. [FTIR and 13C NMR Analysis of Dissolved Organic Matter (DOM) in the Treatment Process of Tannery Wastewater].

    Science.gov (United States)

    Fan, Chun-hui; Zhang, Ying-chao; Tang, Ze-heng; Wang, Jia-hong

    2015-05-01

    Nowadays, the wastewater quantity discharged yearly from tannery industry is around 0. 2 billion t in China. The contaminants of tannery wastewater include macromolecular organic matters, such as grease, fur scraps and collagen, and the alkaline wastewater appears to be of high content of salt and COD. The quality of tannery wastewater is monitored strictly among all kinds of industry wastewater. In the treatment process of tannery wastewater, the quality of inlet and outlet water is generally analyzed. In fact, the transformation behavior of contaminants should be additionally checked to optimize the treatment conditions. Dissolved organic matter (DOM) is commonly existed in water-bodies and helpful to understand the physicochemical characteristics, while the related work should be further studied on tannery wastewater. The approaches of elemental analysis, thermal gravimetric analysis (TG), Fourier infrared spectroscopy (FTIR) and 13C nuclear magnetic resonance (13C NMR) were used to reveal the characteristics of DOM in the treatment process of tannery wastewater. The results showed the carbon content of DOM samples increased gradually, atomic ratios of H/C increased firstly and then decreased, indicating the organic matters were decomposed into chain structures firstly, finally forming the component hard to degraded. The pyrolysis process of DOM mainly proceeded in the regions of 110~530 °C (aliphatic compound, protein, etc. ) and 530~800 °C (aromatic ring, single bond of C-C, etc. ). The functional groups of DOM included -OH, -NH2, C=O and so on, and the aromatic substances were detected, shown from FTIR figures, in the later period of the reaction, caused by the metabolism effect of micro-organism. The content of alkoxy-C increased to the maximum in the second biochemical pond, and the minimum content of aromatic-C appeared in the second biochemical pond, suggesting the transformation behavior of carbon functional groups. The investigation on DOM in tannery

  16. Does the Shuram δ13C excursion record Ediacaran oxygenation?

    Science.gov (United States)

    Husson, J. M.; Maloof, A. C.; Schoene, B.; Higgins, J. A.

    2013-12-01

    The most negative carbon isotope excursion in Earth history is found in carbonate rocks of the Ediacaran Period (635-542 Ma). Known colloquially as the the 'Shuram' excursion, workers have long noted its tantalizing, broad concordance with the rise of abundant macro-scale fossils in the rock record, variously interpreted as animals, giant protists, macro-algae and lichen, and known as the 'Ediacaran Biota.' Thus, the Shuram excursion has been interpreted by many in the context of a dramatically changing redox state of the Ediacaran oceans - e.g., a result of methane cycling in a low O2 atmosphere, the final destruction of a large pool of recalcitrant dissolved organic carbon (DOC), and the step-wise oxidation of the Ediacaran oceans. More recently, diagenetic interpretations of the Shuram excursion - e.g. sedimentary in-growth of very δ13C depleted authigenic carbonates, meteoric alteration of Ediacaran carbonates, late-stage burial diagenesis - have challenged the various Ediacaran redox models. A rigorous geologic context is required to discriminate between these explanatory models, and determine whether the Shuram excursion can be used to evaluate terminal Neoproterozoic oxygenation. Here, we present chemo-stratigraphic data (δ13C, δ18O, δ44/42Ca and redox sensitive trace element abundances) from 12 measured sections of the Ediacaran-aged Wonoka Formation (Fm.) of South Australia that require a syn-depositional age for the extraordinary range of δ13C values (-12 to +4‰) observed in the formation. In some locations, the Wonoka Fm. is ~700 meters (m) of mixed shelf limestones and siliclastics that record the full 16 ‰ δ13C excursion in a remarkably consistent fashion across 100s of square kilometers of basin area. Fabric-altering diagenesis, where present, occurs at the sub-meter vertical scale, only results in sub-permil offsets in δ13C and cannot be used to explain the full δ13C excursion. In other places, the Wonoka Fm. is host to deep (1 km

  17. Recent insights into intramolecular 13C isotope composition of biomolecules

    Science.gov (United States)

    Gilbert, A.; Yamada, K.; Julien, M.; Yoshida, N.; Remaud, G.; Robins, R.

    2016-12-01

    In 1961 Abelson & Hoering shown that the intramolecular 13C distribution in amino acids was not homogeneous, namely the carboxylic acid positions were 13C-enriched compared with the mean of the remaining C-atoms in the molecule [1]. Nearly 20 years later, Monson & Hayes were able to demonstrate that even and odd positions in acetogenic fatty acids also showed non-statistical 13C isotope distributions, and that the pattern varied depending on the organism [2]. It took a further decade for the intramolecular 13C distribution in the key metabolite, glucose, to be defined [3]. Although informative, much of this work was incomplete, a number of positions having to be deduced by difference. This limitation arose mainly due to the lack of techniques enabling the separation and quantification of 13C isotopomers of the target molecule. In the past decade, quantitative 13C NMR has been developed for the determination of the intramolecular isotope composition of a given molecule with a precision of 1‰ or better [4]. This breakthrough has made possible a comprehensive view of the determinants governing intramolecular isotope composition of biological molecules. In particular, it can be shown that intramolecular pattern in sugars is influenced by the C-assimilation pathway and by post-photosynthetic fractionation associated with carbohydrate metabolism [5]. In addition, analysis by NMR of the alkyl chain of acetogenic lipids (fatty acids, n-alkanes) shows an alternation between odd and even C-atom positions, as observed by Monson& Hayes [2], throughout the molecule [6]. Overall, it is becoming apparent that this pattern is influenced by two principal metabolic factors: (i) the 13C pattern extant in the starting compounds; (ii) isotope fractionation associated with the enzymes involved in the biosynthetic pathway. On the whole, the determination of intramolecular isotope patterns in biomolecules allows better insights into the conditions and pathways by which they are formed

  18. All-optical hyperpolarization of electron and nuclear spins in diamond

    Science.gov (United States)

    Green, B. L.; Breeze, B. G.; Rees, G. J.; Hanna, J. V.; Chou, J.-P.; Ivády, V.; Gali, A.; Newton, M. E.

    2017-08-01

    Low thermal polarization of nuclear spins is a primary sensitivity limitation for nuclear magnetic resonance. Here we demonstrate optically pumped (microwave-free) nuclear spin polarization of 13C and 15N in 15N-doped diamond. 15N polarization enhancements up to -2000 above thermal equilibrium are observed in the paramagnetic system Ns0 . Nuclear spin polarization is shown to diffuse to bulk 13C with NMR enhancements of -200 at room temperature and -500 at 240 K, enabling a route to microwave-free high-sensitivity NMR study of biological samples in ambient conditions.

  19. Metabolism of (1-(13)C) glucose and (2-(13)C, 2-(2)H(3)) acetate in the neuronal and glial compartments of the adult rat brain as detected by [(13)C, (2)H] NMR spectroscopy.

    Science.gov (United States)

    Chapa, F; Cruz, F; García-Martín, M L; García-Espinosa, M A; Cerdán, S

    2000-01-01

    Ex vivo ¿(13)C, (2)H¿ NMR spectroscopy allowed to estimate the relative sizes of neuronal and glial glutamate pools and the relative contributions of (1-(13)C) glucose and (2-(13)C, 2-(2)H(3)) acetate to the neuronal and glial tricarboxylic acid cycles of the adult rat brain. Rats were infused during 60 min in the right jugular vein with solutions containing (2-(13)C, 2-(2)H(3)) acetate and (1-(13)C) glucose or (2-(13)C, 2-(2)H(3)) acetate only. At the end of the infusion the brains were frozen in situ and perchloric acid extracts were prepared and analyzed by high resolution (13)C NMR spectroscopy (90.5 MHz). The relative sizes of the neuronal and glial glutamate pools and the contributions of acetyl-CoA molecules derived from (2-(13)C, (2)H(3)) acetate or (1-(13)C) glucose entering the tricarboxylic acid cycles of both compartments, could be determined by the analysis of (2)H-(13)C multiplets and (2)H induced isotopic shifts observed in the C4 carbon resonances of glutamate and glutamine. During the infusions with (2-(13)C, 2-(2)H(3)) acetate and (1-(13)C) glucose, the glial glutamate pool contributed 9% of total cerebral glutamate being derived from (2-(13)C, 2-(2)H(3)) acetyl-CoA (4%), (2-(13)C) acetyl-CoA (3%) and recycled (2-(13)C, 2-(2)H) acetyl-CoA (2%). The neuronal glutamate pool accounted for 91% of the total cerebral glutamate being mainly originated from (2-(13)C) acetyl-CoA (86%) and (2-(13)C, 2-(2)H) acetyl-CoA (5%). During the infusions of (2-(13)C, 2-(2)H(3)) acetate only, the glial glutamate pool contributed 73% of the cerebral glutamate, being derived from (2-(13)C, 2-(2)H(3)) acetyl-CoA (36%), (2-(13)C, 2-(2)H) acetyl-CoA (27%) and (2-(13)C) acetyl-CoA (10%). The neuronal pool contributed 27% of cerebral glutamate being formed from (2-(13)C) acetyl-CoA (11%) and recycled (2-(13)C, 2-(2)H) acetyl-CoA (16%). These results illustrate the potential of ¿(13)C, (2)H¿ NMR spectroscopy as a novel approach to investigate substrate selection and

  20. Design of a quadrature surface coil for hyperpolarized 13C MRS cardiac metabolism studies in pigs

    DEFF Research Database (Denmark)

    Giovannetti, G.; Frijia, F.; Hartwig, V.;

    2013-01-01

    This work describes the design of a quadrature surface coil constituted by a circular loop and a butterfly coil, employed in transmit/receive (TX/RX) mode for hyperpolarized 13C studies of pig heart with a clinical 3T scanner. The coil characterization is performed by developing an SNR model...... for coil performance evaluation in terms of coil resistance, sample-induced resistance and magnetic field pattern. Experimental SNR-vs.-depth profiles, extracted from the [1-13C]acetate phantom chemical shift image (CSI), showed good agreement with the theoretical SNR-vs.-depth profiles. Moreover......, the performance of the quadrature coil was compared with the single TX/RX circular and TX/RX butterfly coil, in order to verify the advantage of the proposed configuration over the single coils throughout the volume of interest for cardiac imaging in pig. Finally, the quadrature surface coil was tested...

  1. Novel nuclear magnetic resonance techniques for studying biological molecules

    Energy Technology Data Exchange (ETDEWEB)

    Laws, David Douglas [Univ. of California, Berkeley, CA (United States)

    2000-06-01

    Over the fifty-five year history of Nuclear Magnetic Resonance (NMR), considerable progress has been made in the development of techniques for studying the structure, function, and dynamics of biological molecules. The majority of this research has involved the development of multi-dimensional NMR experiments for studying molecules in solution, although in recent years a number of groups have begun to explore NMR methods for studying biological systems in the solid-state. Despite this new effort, a need still exists for the development of techniques that improve sensitivity, maximize information, and take advantage of all the NMR interactions available in biological molecules. In this dissertation, a variety of novel NMR techniques for studying biomolecules are discussed. A method for determining backbone (Φ/Ψ) dihedral angles by comparing experimentally determined 13Ca, chemical-shift anisotropies with theoretical calculations is presented, along with a brief description of the theory behind chemical-shift computation in proteins and peptides. The utility of the Spin-Polarization Induced Nuclear Overhauser Effect (SPINOE) to selectively enhance NMR signals in solution is examined in a variety of systems, as are methods for extracting structural information from cross-relaxation rates that can be measured in SPINOE experiments. Techniques for the production of supercritical and liquid laser-polarized xenon are discussed, as well as the prospects for using optically pumped xenon as a polarizing solvent. In addition, a detailed study of the structure of PrP 89-143 is presented. PrP 89-143 is a 54 residue fragment of the prion proteins which, upon mutation and aggregation, can induce prion diseases in transgenic mice. Whereas the structure of the wild-type PrP 89-143 is a generally unstructured mixture of α-helical and β-sheet conformers in the solid state, the aggregates formed from the PrP 89-143 mutants appear to be mostly β-sheet.

  2. Nuclear magnetic resonance of laser-polarized noble gases in molecules, materials and organisms

    Energy Technology Data Exchange (ETDEWEB)

    Goodson, Boyd McLean [Univ. of California, Berkeley, CA (United States)

    1999-12-01

    Conventional nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) are fundamentally challenged by the insensitivity that stems from the ordinarily low spin polarization achievable in even the strongest NMR magnets. However, by transferring angular momentum from laser light to electronic and nuclear spins, optical pumping methods can increase the nuclear spin polarization of noble gases by several orders of magnitude, thereby greatly enhancing their NMR sensitivity. This dissertation is primarily concerned with the principles and practice of optically pumped nuclear magnetic resonance (OPNMR). The enormous sensitivity enhancement afforded by optical pumping noble gases can be exploited to permit a variety of novel NMR experiments across many disciplines. Many such experiments are reviewed, including the void-space imaging of organisms and materials, NMR and MRI of living tissues, probing structure and dynamics of molecules in solution and on surfaces, and zero-field NMR and MRI.

  3. Quantification of lipoprotein profiles by nuclear magnetic resonance spectroscopy and multivariate data analysis

    DEFF Research Database (Denmark)

    Aru, Violetta; Lam, Chloie; Khakimov, Bekzod

    2017-01-01

    Lipoproteins and their subfraction profiles have been associated to diverse diseases including Cardio Vascular Disease (CVD). There is thus a great demand for measuring and quantifying the lipoprotein profile in an efficient and accurate manner. Nuclear Magnetic Resonance (NMR) spectroscopy...

  4. QED calculation of the nuclear magnetic shielding for hydrogen-like ions

    CERN Document Server

    Yerokhin, V A; Harman, Z; Keitel, C H

    2012-01-01

    We report an ab initio calculation of the shielding of the nuclear magnetic moment by the bound electron in hydrogen-like ions. This investigation takes into account several effects that have not been calculated before (electron self-energy, vacuum polarization, nuclear magnetization distribution), thus bringing the theory to the point where further progress is impeded by the uncertainty due to nuclear-structure effects. The QED corrections are calculated to all orders in the nuclear binding strength parameter and, independently, to the leading order in the expansion in this parameter. The results obtained lay the ground for the high-precision determination of nuclear magnetic dipole moments from measurements of the g-factor of hydrogen-like ions.

  5. Developing hyperpolarized krypton-83 for nuclear magnetic resonance spectroscopy and magnetic resonance imaging

    Science.gov (United States)

    Cleveland, Zackary I.

    This dissertation discusses the production of highly nonequilibrium nuclear spin polarization, referred to as hyperpolarization or hp, in the nuclear spin I = 9/2 noble gas isotope krypton-83 using spin exchange optical pumping (SEOP). This nonequilibrium polarization yields nuclear magnetic resonance (NMR) signals that are enhanced three or more orders of magnitude above those of thermally polarized krypton and enables experiments that would otherwise be impossible. Krypton-83 possesses a nuclear electric quadrupole moment that dominates the longitudinal (T1) relaxation due to coupling of the quadrupole moment to fluctuating electric field gradients generated by distortions to the spherical symmetry of the electronic environment. Relaxation slows polarization buildup and limits the maximum signal intensity but makes krypton-83 a sensitive probe of its environment. The gas-phase krypton-83 longitudinal relaxation rate increases linearly with total gas density due to binary collisions. Density independent relaxation, caused by the formation of krypton-krypton van der Waals molecules and surface adsorption, also contributes to the observed rate. Buffer gases suppress van der Waals molecule mediated relaxation by breaking apart the weakly bound krypton dimers. Surface relaxation is gas composition independent and therefore more difficult to suppress. However, this relaxation mechanism makes hp krypton-83 sensitive to important surface properties including surface-to-volume ratio, surface chemistry, and surface temperature. The presence of surfaces with high krypton adsorption affinities (i.e. hydrophobic surfaces) accelerates the relaxation times and can produce T1 contrast in hp krypton-83 magnetic resonance imaging (MRI). Tobacco smoke deposited on surfaces generates strong T1 contrast allowing the observation of smoke deposition with spatial resolution. Conversely, water adsorption on surfaces significantly lengths the T1 times due competitive surface adsorption

  6. Time-odd mean fields in the rotating frame microscopic nature of nuclear magnetism

    CERN Document Server

    Afanasiev, A V

    2000-01-01

    The microscopic role of nuclear magnetism in rotating frame is investigated for the first time in the framework of the cranked relativistic mean field theory. It is shown that nuclear magnetism modifies the expectation values of single-particle spin, orbital and total angular momenta along the rotational axis effectively creating additional angular momentum. This effect leads to the increase of kinematic and dynamic moments of inertia at given rotational frequency and has an impact on effective alignments.

  7. In Vivo Phenotyping of Tumor Metabolism in a Canine Cancer Patient with Simultaneous (18)F-FDG-PET and Hyperpolarized (13)C-Pyruvate Magnetic Resonance Spectroscopic Imaging (hyperPET): Mismatch Demonstrates that FDG may not Always Reflect the Warburg Effect

    DEFF Research Database (Denmark)

    Gutte, Henrik; Hansen, Adam E; Larsen, Majbrit M E

    2015-01-01

    In this communication the mismatch between simultaneous (18)F-FDG-PET and a (13)C-lactate imaging (hyperPET) in a biopsy verified squamous cell carcinoma in the right tonsil of a canine cancer patient is shown. The results demonstrate that (18)F-FDG-PET may not always reflect the Warburg effect...

  8. Structural characterization of a poly(methacrylic acid)-poly(methyl methacrylate) copolymer by nuclear magnetic resonance and mass spectrometry.

    Science.gov (United States)

    Giordanengo, Rémi; Viel, Stéphane; Hidalgo, Manuel; Allard-Breton, Béatrice; Thévand, André; Charles, Laurence

    2009-11-03

    Mass spectrometry (MS) and nuclear magnetic resonance (NMR) have been combined to achieve the complete microstructural characterization of a poly(methacrylic acid)-poly(methyl methacrylate) (PMAA-PMMA) copolymer synthesized by nitroxide-mediated polymerization. Various PMAA-PMMA species could be identified which mainly differ in terms of terminaisons. 1H and 13C NMR experiments revealed the structure of the end-groups as well as the proportion of each co-monomer in the copolymers. These end-group masses were further confirmed from m/z values of doubly charged copolymer anions detected in the single stage mass spectrum. In contrast, copolymer composition derived from MS data was not consistent with NMR results, obviously due to strong mass bias well known to occur during electrospray ionization of these polymeric species. Tandem mass spectrometry could reveal the random nature of the copolymer based on typical dissociation reactions, i.e., water elimination occurred from any two contiguous MAA units while MAA-MMA pairs gave rise to the loss of a methanol molecule. Polymer backbone cleavages were also observed to occur and gave low abundance fragment ions which allowed the structure of the initiating end-group to be confirmed.

  9. Structural characterization of a poly(methacrylic acid)-poly(methyl methacrylate) copolymer by nuclear magnetic resonance and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Giordanengo, Remi [Universites Aix-Marseille I, II et III - CNRS, UMR 6264: Laboratoire Chimie Provence, Spectrometries Appliquees a la Chimie Structurale, F-13397 Marseille (France); Viel, Stephane [Aix-Marseille Universite - CNRS, UMR 6263: Institut des Sciences Moleculaires de Marseille, Chimiometrie et Spectrometries, F-13397 Marseille (France); Hidalgo, Manuel; Allard-Breton, Beatrice [ARKEMA, Centre de Recherche Rhone Alpes, Rue Henri Moissan, F-69493 Pierre-Benite (France); Thevand, Andre [Universites Aix-Marseille I, II et III - CNRS, UMR 6264: Laboratoire Chimie Provence, Spectrometries Appliquees a la Chimie Structurale, F-13397 Marseille (France); Charles, Laurence, E-mail: laurence.charles@univ-provence.fr [Universites Aix-Marseille I, II et III - CNRS, UMR 6264: Laboratoire Chimie Provence, Spectrometries Appliquees a la Chimie Structurale, F-13397 Marseille (France)

    2009-11-03

    Mass spectrometry (MS) and nuclear magnetic resonance (NMR) have been combined to achieve the complete microstructural characterization of a poly(methacrylic acid)-poly(methyl methacrylate) (PMAA-PMMA) copolymer synthesized by nitroxide-mediated polymerization. Various PMAA-PMMA species could be identified which mainly differ in terms of terminaisons. {sup 1}H and {sup 13}C NMR experiments revealed the structure of the end-groups as well as the proportion of each co-monomer in the copolymers. These end-group masses were further confirmed from m/z values of doubly charged copolymer anions detected in the single stage mass spectrum. In contrast, copolymer composition derived from MS data was not consistent with NMR results, obviously due to strong mass bias well known to occur during electrospray ionization of these polymeric species. Tandem mass spectrometry could reveal the random nature of the copolymer based on typical dissociation reactions, i.e., water elimination occurred from any two contiguous MAA units while MAA-MMA pairs gave rise to the loss of a methanol molecule. Polymer backbone cleavages were also observed to occur and gave low abundance fragment ions which allowed the structure of the initiating end-group to be confirmed.

  10. Evaluation of cartilage composition and degradation by high-resolution magic-angle spinning nuclear magnetic resonance.

    Science.gov (United States)

    Schiller, Jürgen; Huster, Daniel; Fuchs, Beate; Naji, Lama; Kaufmann, Jörn; Arnold, Klaus

    2004-01-01

    Rheumatic diseases are accompanied by a progressive destruction of the cartilage layers of the joints. Although the number of patients suffering from rheumatic diseases is steadily increasing, degradation mechanisms of cartilage are not yet understood, and methods for early diagnosis are not available. Although some information on pathogenesis could be obtained from the nuclear magnetic resonance (NMR) spectra of degradation products in the supernatants of cartilage specimens incubated with degradation-causing agents, the most direct information on degradation processes would come from the native cartilage as such. To obtain highly resolved NMR spectra of cartilage, application of the recently developed high-resolution magic-angle spinning (HR-MAS) NMR technique is advisable to obtain small line-widths of individual cartilage resonances. This technique is nowadays commercially available for most NMR spectrometers and has the considerable advantage that the same pulse sequences as in high-resolution NMR can be applied. Except for a MAS spinning equipment, no solid-state NMR hardware is required. Therefore, this method can be easily implemented. Here, we describe the most important requirements that are necessary to record HR-MAS NMR spectra. The capabilities of the HR-MAS technique are discussed for the 1H and 13C NMR spectra of cartilage.

  11. Low- and high-resolution nuclear magnetic resonance (NMR) characterisation of hyaluronan-based native and sulfated hydrogels.

    Science.gov (United States)

    Barbucci, Rolando; Leone, Gemma; Chiumiento, Antonio; Di Cocco, Maria Enrica; D'Orazio, Giovanni; Gianferri, Raffaella; Delfini, Maurizio

    2006-08-14

    Hyaluronan-based hydrogels were synthesised using different crosslinking agents, such as 1,3-diaminopropane (1,3-DAP) and 1,6-diaminohexane (1,6-DAE). The hydrogels were sulfated to provide materials (Hyal-1,3-DAP, Hyal-1,6-DAE, HyalS-1,3-DAP and HyalS-1,6-DAE) that were characterised by both high- and low-resolution nuclear magnetic resonance (NMR) spectroscopy. The (13)C NMR spectra of the materials were analysed to identify, characterise and study the crosslinking degree of the hydrogels. The crosslinking degree was also determined by potentiometric titration and the effectiveness of the two techniques was compared. Measurements of longitudinal relaxation times (spin-lattice) and of NOE enhancement were used to study the mobility of the hydrogels. Low-resolution NMR studies allowed the determination of the water transport properties in the hydrogels. In addition, the swelling degree for the various hydrogels was calculated as a function of the longitudinal and transversal relaxation times of the water molecules. Lastly, the self-diffusion coefficients of the water in interaction with the four polysaccharides were measured by the pulsed field gradient spin echo (PFGSE) sequence.

  12. A Multidisciplinary Approach to High Throughput Nuclear Magnetic Resonance Spectroscopy

    Directory of Open Access Journals (Sweden)

    Hossein Pourmodheji

    2016-06-01

    Full Text Available Nuclear Magnetic Resonance (NMR is a non-contact, powerful structure-elucidation technique for biochemical analysis. NMR spectroscopy is used extensively in a variety of life science applications including drug discovery. However, existing NMR technology is limited in that it cannot run a large number of experiments simultaneously in one unit. Recent advances in micro-fabrication technologies have attracted the attention of researchers to overcome these limitations and significantly accelerate the drug discovery process by developing the next generation of high-throughput NMR spectrometers using Complementary Metal Oxide Semiconductor (CMOS. In this paper, we examine this paradigm shift and explore new design strategies for the development of the next generation of high-throughput NMR spectrometers using CMOS technology. A CMOS NMR system consists of an array of high sensitivity micro-coils integrated with interfacing radio-frequency circuits on the same chip. Herein, we first discuss the key challenges and recent advances in the field of CMOS NMR technology, and then a new design strategy is put forward for the design and implementation of highly sensitive and high-throughput CMOS NMR spectrometers. We thereafter discuss the functionality and applicability of the proposed techniques by demonstrating the results. For microelectronic researchers starting to work in the field of CMOS NMR technology, this paper serves as a tutorial with comprehensive review of state-of-the-art technologies and their performance levels. Based on these levels, the CMOS NMR approach offers unique advantages for high resolution, time-sensitive and high-throughput bimolecular analysis required in a variety of life science applications including drug discovery.

  13. A Multidisciplinary Approach to High Throughput Nuclear Magnetic Resonance Spectroscopy.

    Science.gov (United States)

    Pourmodheji, Hossein; Ghafar-Zadeh, Ebrahim; Magierowski, Sebastian

    2016-06-09

    Nuclear Magnetic Resonance (NMR) is a non-contact, powerful structure-elucidation technique for biochemical analysis. NMR spectroscopy is used extensively in a variety of life science applications including drug discovery. However, existing NMR technology is limited in that it cannot run a large number of experiments simultaneously in one unit. Recent advances in micro-fabrication technologies have attracted the attention of researchers to overcome these limitations and significantly accelerate the drug discovery process by developing the next generation of high-throughput NMR spectrometers using Complementary Metal Oxide Semiconductor (CMOS). In this paper, we examine this paradigm shift and explore new design strategies for the development of the next generation of high-throughput NMR spectrometers using CMOS technology. A CMOS NMR system consists of an array of high sensitivity micro-coils integrated with interfacing radio-frequency circuits on the same chip. Herein, we first discuss the key challenges and recent advances in the field of CMOS NMR technology, and then a new design strategy is put forward for the design and implementation of highly sensitive and high-throughput CMOS NMR spectrometers. We thereafter discuss the functionality and applicability of the proposed techniques by demonstrating the results. For microelectronic researchers starting to work in the field of CMOS NMR technology, this paper serves as a tutorial with comprehensive review of state-of-the-art technologies and their performance levels. Based on these levels, the CMOS NMR approach offers unique advantages for high resolution, time-sensitive and high-throughput bimolecular analysis required in a variety of life science applications including drug discovery.

  14. Nuclear magnetic resonance studies of macroscopic morphology and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Barrall, Geoffrey Alden [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1995-09-01

    Nuclear magnetic resonance techniques are traditionally used to study molecular level structure and dynamics with a noted exception in medically applied NMR imaging (MRI). In this work, new experimental methods and theory are presented relevant to the study of macroscopic morphology and dynamics using NMR field gradient techniques and solid state two-dimensional exchange NMR. The goal in this work is not to take some particular system and study it in great detail, rather it is to show the utility of a number of new and novel techniques using ideal systems primarily as a proof of principle. By taking advantage of the analogy between NMR imaging and diffraction, one may simplify the experiments necessary for characterizing the statistical properties of the sample morphology. For a sample composed of many small features, e.g. a porous medium, the NMR diffraction techniques take advantage of both the narrow spatial range and spatial isotropy of the sample`s density autocorrelation function to obtain high resolution structural information in considerably less time than that required by conventional NMR imaging approaches. The time savings of the technique indicates that NMR diffraction is capable of finer spatial resolution than conventional NMR imaging techniques. Radio frequency NMR imaging with a coaxial resonator represents the first use of cylindrically symmetric field gradients in imaging. The apparatus as built has achieved resolution at the micron level for water samples, and has the potential to be very useful in the imaging of circularly symmetric systems. The study of displacement probability densities in flow through a random porous medium has revealed the presence of features related to the interconnectedness of the void volumes. The pulsed gradient techniques used have proven successful at measuring flow properties for time and length scales considerably shorter than those studied by more conventional techniques.

  15. Calculation of nuclear matter in the presence of strong magnetic field using LOCV technique

    CERN Document Server

    Bordbar, G H

    2015-01-01

    In the present work, we are interested in the properties of nuclear matter at zero temperature in the presence of strong magnetic fields using the lowest order constraint variational (LOCV) method employing $AV_{18}$ nuclear potential. Our results indicate that in the absence of a magnetic field, the energy per particle is a symmetric function of the spin polarization parameter. This shows that for the nuclear matter, the spontaneous phase transition to a ferromagnetic state does not occur. However, we have found that for the magnetic fields $ B\\gtrsim 10 ^ {18}\\ G$, the symmetry of energy is broken and the energy has a minimum at a positive value of the spin polarization parameter. We have also found that the effect of magnetic field on the value of energy is more significant at the low densities. Our calculations show that at lower densities, the spin polarization parameter is more sensitive to the magnetic field.

  16. Pulsed Field Gradient Nuclear Magnetic Resonance and Applications in Yttrium Type Zeolites

    Science.gov (United States)

    Wu, Shaoxiong

    Molecular self-diffusion measurements by Pulsed Field Gradient Nuclear Magnetic Resonance (PFG NMR) spectroscopy can be applied to numerous fields. PFG NMR spectroscopy usually requires no special labeling for measuring hydrocarbon self-diffusion in a variety of samples. This is a significant advantage over using radioactive isotopes or photolabeled molecules since no special sample preparation or handling is required. A single set of experiments can yield diffusion coefficients and often can be performed in a few hours. The range of diffusion coefficients (10^{ -4} cm^2/s-10 ^{-10} cm^2/s) which can be determined by PFG NMR covers most ranges of molecular diffusion. This work describes the design of a PFG NMR spectrometer for measuring hydrocarbon self-diffusion in zeolites. The principles of PFG NMR spectroscopy are illustrated. A pulsed field gradient 60 MHz NMR spectrometer was constructed. Diffusion data were acquired by PFG NMR for standard samples of water, ammonia and glycerol and are in good agreement with those reported in the literature. Following verification of spectrometer performance, the self-diffusion coefficients of isobutane in cation exchanged Y type zeolites were determined. The results show that the mobility of molecules in zeolites depends on the nature of the cations. For small crystallite zeolites, intercrystalline and intracrystalline diffusion has been observed. The effective diffusion coefficients strongly depend on the concentration of adsorbate as well as the packing method. Large discrepancies between diffusion coefficients in zeolites measured by PFG NMR and by adsorption rate experiments have been reported. Surface area, crystallite size, percentage of water in the zeolite, percentage of cation exchanged into the zeolite and other physical chemical properties effect hydrocarbon diffusivity. Detailed methods for determining these properties are discussed. As an extended study of zeolite catalysts, the adsorption of ethylene on

  17. Cardiac metabolism measured noninvasively by hyperpolarized 13C MRI

    DEFF Research Database (Denmark)

    Golman, K.; Petersson, J.S.; Magnusson, P.

    2008-01-01

    Pyruvate is included in the energy production of the heart muscle and is metabolized into lactate, alanine, and CO(2) in equilibrium with HCO(3) (-). The aim of this study was to evaluate the feasibility of using (13)C hyperpolarization enhanced MRI to monitor pyruvate metabolism in the heart...... was almost absent (0.2-11%) and the alanine signal was reduced (27-51%). Due to image-folding artifacts the data obtained for lactate were inconclusive. These studies demonstrate that cardiac metabolic imaging with hyperpolarized 1-(13)C-pyruvate is feasible. The changes in concentrations of the metabolites...... within a minute after injection can be detected and metabolic maps constructed Udgivelsesdato: 2008/5...

  18. 脂肪胺类化合物的13C核磁共振波谱模拟%Prediction of 13C-Nuclear Magnetic Resonance Chemical Shifts for Aliphatic Amines

    Institute of Scientific and Technical Information of China (English)

    许禄; 胡建强

    2001-01-01

    对脂肪胺类化合物的13C核磁共振波谱进行了模拟,所用方法为数学模型法.为此,提取了共振碳原子所处化学环境的拓扑特征、几何特征及电子特征.运用变量最优子集回归法对变量进行了选择,用多元回归法构造了数学模型,得到了比较满意的预测结果.

  19. Direct 13C NMR Detection in HPLC Hyphenation Mode

    DEFF Research Database (Denmark)

    Wubshet, Sileshi Gizachew; Johansen, Kenneth; Nyberg, Nils

    2012-01-01

    Solid phase extraction (SPE) was introduced as a crucial step in the HPLC-SPE-NMR technique to enable online analyte enrichment from which proton-detected NMR experiments on submicrogram amounts from complex mixtures were possible. However, the significance of direct-detected (13)C NMR experiments......, and an acquisition time of 13 h resulted in spectra with adequate signal-to-noise ratios to detect all C-13 signals....

  20. Hyperpolarized 13C MR Markers of Renal Tumor Aggressiveness

    Science.gov (United States)

    2015-12-01

    detection of HP citrate and glutamate allows a measurement of flux through the citric acid cycle , and following cardiac ischemia, the TCA cycle ...biomedical research potential. For instance, the directionality of reactions within the citric acid cycle has become an area of increased interest as...incorporated into tricarboxylic acid (TCA) cycle intermediates rather than being released as 13CO2. This makes [2- 13C]pyruvate an attractive

  1. High resolution 13C DOSY: The DEPTSE experiment

    Science.gov (United States)

    Botana, Adolfo; Howe, Peter W. A.; Caër, Valérie; Morris, Gareth A.; Nilsson, Mathias

    2011-07-01

    High Resolution Diffusion-ordered Spectroscopy (HR-DOSY) is a valuable tool for mixture analysis by NMR. It separates the signals from different components according to their diffusion behavior, and can provide exquisite diffusion resolution when there is no signal overlap. In HR-DOSY experiments on 1H (by far the most common nucleus used for DOSY) there is frequent signal overlap that confuses interpretation. In contrast, a 13C spectrum usually has little overlap, and is in this respect a much better option for a DOSY experiment. The low signal-to-noise ratio is a critical limiting factor, but with recent technical advances such as cryogenic probes this problem is now less acute. The most widely-used pulse sequences for 13C DOSY perform diffusion encoding with 1H, using a stimulated echo in which half of the signal is lost. This signal loss can be avoided by encoding diffusion with 13C in a spin echo experiment such as the DEPTSE pulse sequence described here.

  2. PEDOGENIC CARBONATE δ13C AND ENVIRONMENTAL PRECIPITATION CONDITIONS

    Directory of Open Access Journals (Sweden)

    Marcella Catoni

    2011-12-01

    Full Text Available Carbon isotopic analysis is a useful tool for investigating paleoenvironments, as the pedogenic carbonate δ13C is related to δ13CSOM and to the proportions of C3/C4 plants. In this work we interpreted the paleoenvironmental conditions at the time of carbonate precipitation in soils formed under different climates and during different geological ages. Samples were taken from a Bk (PR1, Holocene and from two Bkm horizons (PR2 and PR3, Pleistocene. When the mean δ13C plant values and the most plausible paleotemperatures were used in the evaluation, PR1 showed a lower percentage of C4 plants (48% than Pleistocene soils (~53%, in agreement with paleoclimate changes. When instead the δ13C values of current plants were used for PR1, C4 plants ranged from 59 (12°C to 66% (18°C, suggesting two possible interpretations: either plant species changed during the Holocene, or the plant mean values normally used in the literature are not suitable for Pleistocene reconstructions

  3. 14N + 13C fusion cross sections and compound nucleus limitation in 27Al

    Science.gov (United States)

    Digregorio, D. E.; Gomez del Campo, J.; Chan, Y. D.; Ford, J. L. C., Jr.; Shapira, D.; Ortiz, M. E.

    1982-10-01

    Fusion cross sections for the 14N + 13C system have been measured by detecting the evaporation residues at five bombarding energies which correspond to high excitation energies in the compound nucleus: E*(27Al)=64-110 MeV. The 27Al nucleus can be populated by four different heavy-ion entrance channels-15N + 12C, 16O + 11B, 14N + 13C, and 17O + 10B-which are accessible to experimental measurements. Comparing the present data with those already existing for the above channels, it is found that for E*>60 MeV the curves E* vs Jcr for each system converge, which may be indicative of a limitation imposed by the compound nucleus. The data are discussed in terms of existing models for entrance channel and statistical yrast line limitations. The highest energy point also suggests the existence of a maximum absolute angular momentum limit of ~28ℏ. NUCLEAR REACTIONS 14N + 13C E(14N)=86.0, 103.8, 149.0, 161.3, and 180.0 MeV; measured d2σdΩdE for reaction products from Z=5 to 12. Extracted σfus, σD, σR.

  4. Further evidence for a dynamically generated secondary bow in $^{13}$C+$^{12}$C rainbow scattering

    CERN Document Server

    Ohkubo, S; Ogloblin, A A

    2015-01-01

    The existence of a secondary bow is confirmed for 13C+12C nuclear rainbow scattering in addition to the 16O+12C system. This is found by studying the experimental angular distribution of 13C+12C scattering at the incident 13C energy $E_L$=250 MeV with an extended double folding (EDF) model that describes all the diagonal and off-diagonal coupling potentials derived from the microscopic wave functions for 12C using a density-dependent nucleon-nucleon force. The Airy minimum at \\theta$ $\\approx$70$^\\circ$, which is not reproduced by a conventional folding potential, is revealed to be a secondary bow generated dynamically by a coupling to the excited state 2+ (4.44 MeV) of 12C. The essential importance of the quadruple {\\it Y2} term (reorientation term) of potential of the excited state 2+ of 12C for the emergence of a secondary bow is found. The mechanism of the secondary bow is intuitively explained by showing how the trajectories are refracted dynamically into the classically forbidden angular region beyond t...

  5. Carbon-thirteen cross-polarization magic angle spinning nuclear magnetic resonance and Fourier transform infrared studies of thermally modified wood exposed to brown and soft rot fungi.

    Science.gov (United States)

    Sivonen, Hanne; Nuopponen, Mari; Maunu, Sirkka L; Sundholm, Franciska; Vuorinen, Tapani

    2003-03-01

    Thermally modified wood has many technically interesting properties, such as increased dimensional stability, low equilibrium moisture content, and enhanced biological and weather resistance. This paper describes solid-state nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectroscopic studies on the decay of heat-treated and untreated pine (Pinus sylvestris) by brown (Poria placenta) and soft rot fungi. Both techniques combined with multivariate data analysis proved to be powerful tools for the study of wood degradation by fungi. When untreated pine was exposed to brown or soft rot fungi, a drastic decay of the cell wall polysaccharides was observed. Brown rot fungus degraded mainly hemicelluloses while soft rot fungus attacked cellulose more extensively. The aromatic region of 13C cross-polarization magic angle spinning (CPMAS) NMR spectra revealed that the structure of lignin was also altered. New carboxylic structures were formed as a consequence of the decay. The increased biological resistance of pine wood heat-treated at >220 degrees C was observed in the 13C CPMAS NMR and IR spectra.

  6. Pharmaceutical Applications of Relaxation Filter-Selective Signal Excitation Methods for ¹⁹F Solid-State Nuclear Magnetic Resonance: Case Study With Atorvastatin in Dosage Formulation.

    Science.gov (United States)

    Asada, Mamiko Nasu; Nemoto, Takayuki; Mimura, Hisashi

    2016-03-01

    We recently developed several new relaxation filter-selective signal excitation (RFS) methods for (13)C solid-state nuclear magnetic resonance (NMR) that allow (13)C signal extraction of the target components from pharmaceuticals. These methods were successful in not only qualification but also quantitation over the wide range of 5% to 100%. Here, we aimed to improve the sensitivity of these methods and initially applied them to (19)F solid-state NMR, on the basis that the fluorine atom is one of the most sensitive NMR-active nuclei. For testing, we selected atorvastatin calcium (ATC), an antilipid BCS class II drug that inhibits 3-hydroxy-3-methylglutaryl-coenzyme A reductase and is marketed in crystalline and amorphous forms. Tablets were obtained from 2 generic drug suppliers, and the ATC content occurred mainly as an amorphous form. Using the RFS method with (19)F solid-state NMR, we succeeded in qualifying trace amounts (less than 0.5% w/w level) of crystalline phase (Form I) of ATC in the tablets. RFS methods with (19)F solid-state NMR are practical and time efficient and can contribute not only to the study of pharmaceutical drugs, including those with small amounts of a highly potent active ingredient within a formulated product, but also to the study of fluoropolymers in material sciences. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  7. Carbon-13 nuclear magnetic resonance spectroscopy of lipids: Differential line broadening due to cross-correlation effects as a probe of membrane structure

    Energy Technology Data Exchange (ETDEWEB)

    Oldfield, E.; Adebodun, F.; Chung, J.; Montez, B.; Ki Deok Park; Hongbiao Le; Phillips, B. (Univ. of Illinois, Urbana (United States))

    1991-11-19

    The authors have obtained proton-coupled carbon-13 nuclear magnetic resonance (NMR) spectra of a variety of lipid-water and lipid-drug-water systems, at 11.7 T, as a function of temperature, using the 'magic-angle' sample-spinning (MAS) NMR technique. The resulting spectra show a wide range of line shapes, due to interferences between dipole-dipole and dipole-chemical shielding anisotropy interactions. The differential line-broadening effects observed are particularly large for aromatic and olefinic (sp{sup 2}) carbon atom sites. Coupled spectra of the tricyclic antidepressants desipramine and imipramine, in 1,2-dimyristoyl-sn-glycero-3-phosphocholine-water mesophases, show well-resolved doublets having different line shapes for each of the four aromatic methine groups, due to selective averaging of the four C-H dipolar interactions due to rapid motion about the director (or drug C{sub 2}) axis. {sup 2}H NMR spectra of (2,4,6,8-{sup 2}H{sub 4})desipramine (and imipramine) in the same 1,2-dimyristoyl-sn-glycero-3-phosphocholine-water mesophase exhibit quadrupole splittings of {approximately}0-2 and {approximately}20 kHz, indicating an approximate magic-angle orientation of the C2-{sup 2}H({sup 1}H) and C8-{sup 2}H({sup 1}H) vectors with respect to an axis of motional averaging, in accord with the {sup 13}C NMR results. The good qualitative agreement between {sup 13}C and {sup 2}H NMR results suggests that useful orientational ({sup 2}H NMR like) information can be deduced from natural-abundance {sup 13}C NMR spectra of a variety of mobile solids.

  8. Characterization of oil shale, isolated kerogen, and post-pyrolysis residues using advanced 13 solid-state nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Cao, Xiaoyan; Birdwell, Justin E.; Chappell, Mark A.; Li, Yuan; Pignatello, Joseph J.; Mao, Jingdong

    2013-01-01

    Characterization of oil shale kerogen and organic residues remaining in postpyrolysis spent shale is critical to the understanding of the oil generation process and approaches to dealing with issues related to spent shale. The chemical structure of organic matter in raw oil shale and spent shale samples was examined in this study using advanced solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Oil shale was collected from Mahogany zone outcrops in the Piceance Basin. Five samples were analyzed: (1) raw oil shale, (2) isolated kerogen, (3) oil shale extracted with chloroform, (4) oil shale retorted in an open system at 500°C to mimic surface retorting, and (5) oil shale retorted in a closed system at 360°C to simulate in-situ retorting. The NMR methods applied included quantitative direct polarization with magic-angle spinning at 13 kHz, cross polarization with total sideband suppression, dipolar dephasing, CHn selection, 13C chemical shift anisotropy filtering, and 1H-13C long-range recoupled dipolar dephasing. The NMR results showed that, relative to the raw oil shale, (1) bitumen extraction and kerogen isolation by demineralization removed some oxygen-containing and alkyl moieties; (2) unpyrolyzed samples had low aromatic condensation; (3) oil shale pyrolysis removed aliphatic moieties, leaving behind residues enriched in aromatic carbon; and (4) oil shale retorted in an open system at 500°C contained larger aromatic clusters and more protonated aromatic moieties than oil shale retorted in a closed system at 360°C, which contained more total aromatic carbon with a wide range of cluster sizes.

  9. DMS AND 13C NMR STUDIES ON THE COMPATIBILITY AND DYNAMICS OF LATEX BIDIRECTIONAL IPNS AND LATEX IPN OF PVA c/PBA

    Institute of Scientific and Technical Information of China (English)

    YAN Xin; XU Xiaolong; ZHANG Baozhen; YAO Shuren; QIAN Baogong

    1993-01-01

    The compatibility and dynamics of latex bidirectional interpenetrating polymer networks (LBIPNs) and latex IPN(LIPN) of poly(vinyl acetate)(PVAc) and poly (butyl acrylate )(PBA) are investigated by means of dynamic mechanical spectroscopy (DMS) and nuclear magnetic resonance (NMR) techniques. The results of DMS show that the compatibility of the LBIPNs is much better than that of the corresponding LIPN and depends to a large extent on the distribution of PVAc both in the core and in the shell. The results of NMR measurements indicate that the rotational correlation times of the side- groups of PBA in the LBIPN are longer than those in the LIPN. The relation between the 13C linewidths of PBA and temperature is also discussed.

  10. Metabolism of [U-13C]glucose in Human Brain Tumors In Vivo

    Science.gov (United States)

    Maher, Elizabeth A.; Marin-Valencia, Isaac; Bachoo, Robert M.; Mashimo, Tomoyuki; Raisanen, Jack; Hatanpaa, Kimmo J.; Jindal, Ashish; Jeffrey, F. Mark; Choi, Changho; Madden, Christopher; Mathews, Dana; Pascual, Juan M.; Mickey, Bruce E.; Malloy, Craig R.; DeBerardinis, Ralph J.

    2012-01-01

    Glioblastomas (GBMs) and brain metastases demonstrate avid uptake of 18fluoro-2-deoxyglucose (FDG) by positron emission tomography (PET) and display perturbations of intracellular metabolite pools by 1H magnetic resonance spectroscopy (MRS). These observations suggest that metabolic reprogramming contributes to brain tumor growth in vivo. The Warburg effect, excess metabolism of glucose to lactate in the presence of oxygen, is a hallmark of cancer cells in culture. FDG-positive tumors are assumed to metabolize glucose in a similar manner, with high rates of lactate formation compared to mitochondrial glucose oxidation, but few studies have specifically examined the metabolic fates of glucose in vivo. In particular, the capacity of human brain malignancies to oxidize glucose in the tricarboxylic acid cycle is unknown. Here we studied the metabolism of human brain tumors in situ. [U-13C]glucose was infused during surgical resection, and tumor samples were subsequently subjected to 13C NMR spectroscopy. Analysis of tumor metabolites revealed lactate production, as expected. We also determined that pyruvate dehydrogenase, turnover of the TCA cycle, anaplerosis and de novo glutamine and glycine synthesis contributed significantly to the ultimate disposition of glucose carbon. Surprisingly, less than 50% of the acetyl-CoA pool was derived from blood-borne glucose, suggesting that additional substrates contribute to tumor bioenergetics. This study illustrates a convenient approach that capitalizes on the high information content of 13C NMR spectroscopy and enables the analysis of intermediary metabolism in diverse malignancies growing in their native microenvironment. PMID:22419606

  11. Applications of pulsed nuclear magnetic resonance to chemistry: multiple-pulse NMR, cross polarization, magic-angle spinning annd instrumental design

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, P.D.

    1979-07-01

    Pulsed Nuclear Magnetic Resonance (NMR) has been applied to: (1) Measurements of the prinicpal components of the proton shielding tensors of the hydrides of zirconium chloride and zirconium bromide. Multiple-Pulse techniques have been used to remove static homonuclear dipolar coupling. The anisotropies and isotropic shifts of these tensors have been used to infer the possible locations of the hydrogen within the sandwich-like layers of these unusual compounds. (2) Studies of the oscillatory transfer of magnetic polarization between /sup 1/H and /sup 29/Si in substituted silanes. The technique of J Cross Polarization has been used to enhance sensitivity. The /sup 29/Si NMR shifts of -Si-O- model compounds have been investigated as a possible probe for future studies of the environment of bound oxygen in coal-derived liquids. (3) Measurements of the aromatic fraction of /sup 13/C in whole coals. The techniques of /sup 1/H-/sup 13/C Cross Polarization and Magic-Angle Spinning have been used to enhance sensitivity and remove shift anisotropy. Additional topics described are: (4) Calculation and properties of the broadened lineshape of the shileding Powder Pattern. (5) Calculation of the oscillatory transfer of magnetic polarization for an I-S system. (6) Numerical convolution and its uses. (7) The technique of digital filtering applied in the frequency domain. (8) The designs and properties of four NMR probe-circuits. (9) The design of a single-coil double-resonance probe for combined Magic-Angle Spinning and Cross Polarization. (10) The designs of low Q and high Q rf power amplifiers with emphasis on the rf matching circuitry.

  12. Nuclear magnetic resonance at millitesla fields using a zero-field spectrometer

    Science.gov (United States)

    Tayler, Michael C. D.; Sjolander, Tobias F.; Pines, Alexander; Budker, Dmitry

    2016-09-01

    We describe new analytical capabilities for nuclear magnetic resonance (NMR) experiments in which signal detection is performed with chemical resolution (via spin-spin J couplings) in the zero to ultra-low magnetic field region, below 1 μT. Using magnetic fields in the 100 μT to 1 mT range, we demonstrate the implementation of conventional NMR pulse sequences with spin-species selectivity.

  13. Development and applications of NMR (nuclear magnetic resonance) in low fields and zero field

    Energy Technology Data Exchange (ETDEWEB)

    Bielecki, A.

    1987-05-01

    This dissertation is about nuclear magnetic resonance (NMR) spectroscopy in the absence of applied magnetic fields. NMR is usually done in large magnetic fields, often as large as can be practically attained. The motivation for going the opposite way, toward zero field, is that for certain types of materials, particularly powdered or polycrystalline solids, the NMR spectra in zero field are easier to interpret than those obtained in high field. 92 refs., 60 figs., 1 tab.

  14. Solid state 13C NMR of unlabeled phosphatidylcholine bilayers: spectral assignments and measurement of carbon-phosphorus dipolar couplings and 13C chemical shift anisotropies.

    Science.gov (United States)

    Sanders, C R

    1993-01-01

    The direct measurement of 13C chemical shift anisotropies (CSA) and 31P-13C dipolar splitting in random dispersions of unlabeled L alpha-phase phosphatidylcholine (PC) has traditionally been difficult because of extreme spectral boradening due to anisotropy. In this study, mixtures of dimyristoyl phosphatidylcholine (DMPC) with three different detergents known to promote the magnetic orientation of DMPC were employed to eliminate the powder-pattern nature of signals without totally averaging out spectral anisotropy. The detergents utilized were CHAPSO, Triton X-100, and dihexanoylphosphatidylcholine (DHPC). Using such mixtures, many of the individual 13C resonances from DMPC were resolved and a number of 13C-31P dipolar couplings were evident. In addition, differing line widths were observed for the components of some dipolar doublets, suggestive of dipolar/chemical shift anisotropy (CSA) relaxation interference effects. Oriented sample resonance assignments were made by varying the CHAPSO or DHPC to DMPC ratio to systematically scale overall bilayer order towards the isotropic limit. In this manner, peaks could be identified based upon extrapolation to their isotropic positions, for which assignments have previously been made (Lee, C.W.B., and R.G. Griffin. 1989. Biophys. J. 55:355-358; Forbes, J., J. Bowers, X. Shan, L. Moran, E. Oldfield, and M.A. Moscarello. 1988. J. Chem. Soc., Faraday, Trans. 1 84:3821-3849). It was observed that the plots of CSA or dipolar coupling versus overall bilayer order obtained from DHPC and CHAPSO titrations were linear. Estimates of the intrinsic dipolar couplings and chemical shift anisotropies for pure DMPC bilayers were made by extrapolating shifts and couplings from the detergent titrations to zero detergent. Both detergent titrations led to similar "intrinsic" CSAs and dipolar couplings. Results extracted from an oriented Triton-DMPC mixture also led to similar estimates for the detergent-free DMPC shifts and couplings. The

  15. Unlocking the molecular structure of fungal melanin using 13C biosynthetic labeling and solid-state NMR.

    Science.gov (United States)

    Tian, Shiying; Garcia-Rivera, Javier; Yan, Bin; Casadevall, Arturo; Stark, Ruth E

    2003-07-15

    Melanins are enigmatic pigments found in all biological kingdoms that are associated with a variety of functions, including microbial virulence. Despite being ubiquitous in nature, melanin pigments have long resisted atomic-level structural examination because of their insolubility and amorphous organization. Cryptococcus neoformans is a human pathogenic fungus that melanizes only when provided with exogenous substrate, thus offering a unique system for exploring questions related to melanin structure at the molecular level. We have exploited the requirement for exogenous substrate in melanin synthesis as well as the capabilities of high-resolution solid-state nuclear magnetic resonance (NMR) to establish the predominantly aliphatic composition of l-dopa melanin and to introduce (13)C labels that permit the identification of proximal carbons in the developing biopolymer. By swelling solid melanin samples in organic solvents and using two-dimensional heteronuclear NMR in conjunction with magic-angle spinning, we have identified chemical bonding patterns typical of alkane, alkene, alcohol, ketone, ester, and indole functional groups. These findings demonstrate the feasibility of a novel approach to determining the structure of melanin using metabolic labeling and NMR spectroscopy.

  16. Nuclear ground-state spin and magnetic moment of 21Mg

    CERN Document Server

    Krämer, J; De Rydt, M; Flanagan, K T; Geppert, Ch; Kowalska, M; Lievens, P; Neugart, R; Neyens, G; Nörtershäuser, W; Stroke, H H; Vingerhoets, P; Yordanov, D T

    2009-01-01

    We present the results of combined laser spectroscopy and nuclear magnetic resonance studies of 21Mg. The nuclear ground-state spin was measured to be I=5/2 with a magnetic moment of μ=−0.983(7)μN. The isoscalar magnetic moment of the mirror pair is evaluated and compared to the extreme single-particle prediction and to nuclear shell-model calculations. We determine an isoscalar spin expectation value of σ=1.15(2), which is significantly greater than the empirical limit of unity given by the Schmidt values of the magnetic moments. Shell-model calculations taking into account isospin non-conserving effects, are in agreement with our experimental results.

  17. Coexistence of phases in asymmetric nuclear matter under strong magnetic fields

    CERN Document Server

    Aguirre, R

    2014-01-01

    The equation of state of nuclear matter is strongly affected by the presence of a magnetic field. Here we study the equilibrium configuration of asymmetric nuclear matter for a wide range of densities, isospin composition, temperatures and magnetic fields. Special attention is paid to the low density and low temperature domain, where a thermodynamical instability exists. Neglecting fluctuations of the Coulomb force, a coexistence of phases is found under such conditions, even for extreme magnetic intensities. We describe the nuclear interaction by using the non--relativistic Skyrme potential model within a Hartree--Fock approach. We found that the coexistence of phases modifies the equilibrium configuration, masking most of the manifestations of the spin polarized matter. However, the compressibility and the magnetic susceptibility show clear signals of this fact. Thermal effects are significative for both quantities, mainly out of the coexistence region.

  18. 13C NMR spectra of tectonic coals and the effects of stress on structural components

    Institute of Scientific and Technical Information of China (English)

    JU Yiwen; JIANG Bo; HOU Quanlin; WANG Guiliang; NI Shanqin

    2005-01-01

    High-resolution 13C Nuclear Magnetic Resonance (NMR) spectra of different kinds of tectonic coals were obtained using the NMR (CP/MAS+TOSS) method. On the basis of this, after simulation synthesis and division of spectra, the relative contents of carbon functional groups were calculated. Combined with results of Ro, max, XRD testing and element analysis, stress effects on the composition of macromolecular structures in tectonic coals were studied further. The results showed that Ro, max was not only the important index for describing coal rank, but was also effective for estimating the stress effect of tectonic coals. Under tectonic stress action, Ro, max was the most direct indicator of the coal structure and chemical components. Changes in the stacking Lc of the coal basic structure unit (BSU) and La/Lc parameters could distinguish the temperature and stress effects on metamorphic-deformed environments, and reflected the degree of structural deformation. Therefore, on the whole, Lc and La/Lc can be used to index of the degree of structural deformation of tectonic coals. In different metamorphic and deformed environments, different kinds of tectonic coals are formed under structural stress. The changes in characteristics of the macromolecular structure and chemical composition are such that as the increase in structural deformation becomes stronger, from the brittle deformation coal to ductile deformation coal, the ratio of width at the half height of the aromatic carbon and aliphatic carbon peaks (Hfa/Hfal ) was increased. As carbon aromaticity was raised further, carbon aliphaticity reduced obviously and different compositions of macromolecular structure appeared as a jump and wave pattern except for in wrinkle structure coal, which might result chiefly from stress effects on the macromolecular structure of different kinds of tectonic coals. The macromoecular changes of wrinkle structure coal are reflected mainly on physical structure. In the metamorphic and

  19. Galactose oxidation using 13C in healthy and galactosemic children

    Directory of Open Access Journals (Sweden)

    D.R. Resende-Campanholi

    2015-03-01

    Full Text Available Galactosemia is an inborn error of galactose metabolism that occurs mainly as the outcome of galactose-1-phosphate uridyltransferase (GALT deficiency. The ability to assess galactose oxidation following administration of a galactose-labeled isotope (1-13C-galactose allows the determination of galactose metabolism in a practical manner. We aimed to assess the level of galactose oxidation in both healthy and galactosemic Brazilian children. Twenty-one healthy children and seven children with galactosemia ranging from 1 to 7 years of age were studied. A breath test was used to quantitate 13CO2 enrichment in exhaled air before and at 30, 60, and 120 min after the oral administration of 7 mg/kg of an aqueous solution of 1-13C-galactose to all children. The molar ratios of 13CO2 and 12CO2 were quantified by the mass/charge ratio (m/z of stable isotopes in each air sample by gas-isotope-ratio mass spectrometry. In sick children, the cumulative percentage of 13C from labeled galactose (CUMPCD in the exhaled air ranged from 0.03% at 30 min to 1.67% at 120 min. In contrast, healthy subjects showed a much broader range in CUMPCD, with values from 0.4% at 30 min to 5.58% at 120 min. The study found a significant difference in galactose oxidation between children with and without galactosemia, demonstrating that the breath test is useful in discriminating children with GALT deficiencies.

  20. Quantitative determination Of etimicin sulfate by nuclear magnetic resonance%核磁共振法测定硫酸依替米星含量

    Institute of Scientific and Technical Information of China (English)

    于小波; 相秉仁; 王国华; 宋喆; 沈文斌

    2011-01-01

    Qualitative and quantitative analysis of etimicin sulfate were reported by nuclear magnetic resonance(NMR).The 1H-NMR and 13C-NMR spectra of etimicin sulfate have been assigned by means of 1D and 2D spectroscopy including DEPT, COSY, HSQC and HMBC.On the basis of assignment, a novel approach was developed for the determination of purity of etimicin sulfate by proton-nuclear magnetic resonance (1H-NMR)using p-hydroquinone as internal standard.The result showed that the purity of etimicin was 59.19%, and its relative standard deviations(RSD) was 0.24%, this method was relative accuracy, precision, and ease of application.%通过核磁共振法对硫酸依替米星进行定性和定量分析.利用一维及二维核磁共振谱(DEPT、COSY、HSQC、HMBC),对H-NMR谱和C-NMR谱信号进行完整归属.在此基础上,采用氢核磁共振定量法,以对苯二酚为内标,测得硫酸依替米星中依替米星的含量为59.19%,RSD为0.24%,方法准确可靠,简便快速.

  1. Nuclear magnetic resonance applied to the study of polymeric nano composites; Ressonancia magnetica nuclear aplicada do estudo de nanocompositos polimericos

    Energy Technology Data Exchange (ETDEWEB)

    Tavares, Maria Ines Bruno [Instituto de Macromoleculas Professora Eloisa Mano da Universidade Federal do Rio de Janeiro, UFRJ - RJ (Brazil)

    2011-07-01

    Polymers and nanoparticles based nano composites were prepared by intercalation by solution. The obtained nano composites were characterized mainly by the nuclear magnetic spectroscopy (NMR), applying the analysis of carbon-13 (polymeric matrix), silicon-29 (nanoparticle), and by determination of spin-lattice relaxation of the hydrogen nucleus (T{sub 1}H) (polymeric matrix). The NMR have presented a promising technique in the characterization of the nano charge dispersion in the studied polymeric matrixes.

  2. A combined HNCA/HNCO experiment for {sup 15}N labeled proteins with {sup 13}C at natural abundance

    Energy Technology Data Exchange (ETDEWEB)

    Kupce, Eriks [Varian Inc. (United Kingdom); Muhandiram, D.R.; Kay, Lewis E. [University of Toronto, Protein Engineering Network Centers of Excellence and Departments of Medical Genetics, Biochemistry and Chemistry (Canada)], E-mail: kay@pound.med.utoronto.ca

    2003-10-15

    A triple resonance NMR experiment is presented for the simultaneous recording of HNCA and HNCO data sets on {sup 15}N, natural abundance {sup 13}C samples. The experiment exploits the fact that transfers of magnetization from {sup 15}N to {sup 13}CO and from {sup 15}N to {sup 13}C{sup {alpha}} (and back) proceed independently for samples that are not enriched in {sup 13}C. A factor of 2 in measuring time is gained by recording the two data sets simultaneously with no compromise in spectral quality. An application to a 0.5 mM {sup 15}N labeled sample of protein-L is presented with all expected correlations observed in spectra recorded with a cryogenic probe at 500 MHz.

  3. Design of a sup 13 C (1H) RF probe for monitoring the in vivo metabolism of (1- sup 13 C)glucose in primate brain

    Energy Technology Data Exchange (ETDEWEB)

    Hammer, B.E.; Sacks, W.; Bigler, R.E.; Hennessy, M.J.; Sacks, S.; Fleischer, A.; Zanzonico, P.B. (Intermagnetics General Corporation, Guilderland, NY (USA))

    1990-01-01

    The design of an RF probe suitable for obtaining proton-decoupled {sup 13}C spectra from a subhuman primate brain is described. Two orthogonal saddle coils, one tuned to the resonant frequency of {sup 13}C and the other to the resonant frequency of 1H, were used to monitor the in vivo metabolism of (1-{sup 13}C)glucose in rhesus monkey brain at 2.1 T. Difference spectra showed the appearance of {sup 13}C-enriched glutamate and glutamine 30 to 40 min after a bolus injection of (1-{sup 13}C)glucose.

  4. Glucogenesis in an insect, Manduca sexta L., estimated from the 13C isotopomer distribution in trehalose synthesized from [1,3-13C2]glycerol.

    Science.gov (United States)

    Thompson, S N

    1997-07-19

    Glucogenesis from [3-13C]alanine and [1,3-13C2]glycerol was demonstrated in the insect Manduca sexta by examining the 13C enrichment of trehalose, a non-reducing disaccharide of glucose synthesized in the insect fat body and released into the blood or hemolymph. In insects maintained on a low carbohydrate diet, trehalose synthesized from [3-13C]alanine was selectively enriched at C1 and C6, and C2 and C5. The 13C-labelling pattern indicated the carboxylation of [3-13C]pyruvate, formed by transamination of the [3-13C]alanine followed by randomization of the label at the fumarate step of the tricarboxylic acid cycle and glucose synthesis via the gluconeogenic pathway. 13C enrichment of trehalose was absent in similarly maintained insect larvae administered 3-mercaptopicolinic acid, an inhibitor of hepatic phosphoenolpyruvate carboxykinase. Insects on the low carbohydrate diet also synthesized trehalose from [1,3-13C2]glycerol. 13C multiplets were observed in trehalose C3 and C4 demonstrating the synthesis of three 13C enriched glucose isotopomers from the 13C-labelled glycerol. The relative contributions of 13C-labelled glycerol and unlabelled 3 carbon substrates to the synthesis of the 13C enriched trehalose isotopomers were determined from the multiplet structure at C3, and calculation of minimal rates of glucogenesis were based on the 13C enrichment of C4. The C4/C3 13C enrichment ratio in trehalose synthesized from [1,3-13C2]glycerol was close to unity, and total glucogenesis was calculated after estimation of the expected contribution of unlabelled trehalose synthesis from 3 carbon substrates by comparison of the ratio of unlabelled and labelled contributions to the 13C enriched trehalose isotopomers with the 13C enrichment of [1,3-13C2]glycerol-3-phosphate. The estimated total rates of glucogenesis varied from 0.33 to 2.80 micromol glucose/g fresh weight/h. The blood sugar level of M. sexta was also highly variable. Although the potential importance of

  5. Optically induced dynamic nuclear spin polarisation in diamond

    Science.gov (United States)

    Scheuer, Jochen; Schwartz, Ilai; Chen, Qiong; Schulze-Sünninghausen, David; Carl, Patrick; Höfer, Peter; Retzker, Alexander; Sumiya, Hitoshi; Isoya, Junichi; Luy, Burkhard; Plenio, Martin B.; Naydenov, Boris; Jelezko, Fedor

    2016-01-01

    The sensitivity of magnetic resonance imaging (MRI) depends strongly on nuclear spin polarisation and, motivated by this observation, dynamical nuclear spin polarisation has recently been applied to enhance MRI protocols (Kurhanewicz et al 2011 Neoplasia 13 81). Nuclear spins associated with the 13C carbon isotope (nuclear spin I = 1/2) in diamond possess uniquely long spin lattice relaxation times (Reynhardt and High 2011 Prog. Nucl. Magn. Reson. Spectrosc. 38 37). If they are present in diamond nanocrystals, especially when strongly polarised, they form a promising contrast agent for MRI. Current schemes for achieving nuclear polarisation, however, require cryogenic temperatures. Here we demonstrate an efficient scheme that realises optically induced 13C nuclear spin hyperpolarisation in diamond at room temperature and low ambient magnetic field. Optical pumping of a nitrogen-vacancy centre creates a continuously renewable electron spin polarisation which can be transferred to surrounding 13C nuclear spins. Importantly for future applications we also realise polarisation protocols that are robust against an unknown misalignment between magnetic field and crystal axis.

  6. Chemical structures in pyrodextrin determined by nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Bai, Yanjie; Shi, Yong-Cheng

    2016-10-20

    Glycosidic linkages in a pyrodextrin were identified by NMR spectroscopy for the first time. Pyrodextrin was prepared by slurrying waxy maize starch at pH 3, filtering and drying at 40°C to 10-15% moisture content, then heating at 170°C for 4h. (1)H and (13)C NMR resonances of the pyrodextrin were assigned with the assistance of 2D techniques including COSY, TOCSY, HSQC, and HMBC, all measured on a 500MHz instrument. During dextrinization, native waxy maize starch was hydrolyzed and extensively branched with new glycosidic linkages. The resulting pyrodextrin became 100% soluble in water and produced lower viscosity solutions at 30% solids. There were only 1.2% reducing ends (α-form) detected in the pyrodextrin, but 1,6-anhydro-β-d-glucopyranosyl units accounted for 5.2% of repeating units and they were thought to be at the potential reducing end. New glycosyl linkages including α-1,6, β-1,6, α-1,2, and β-1,2 were identified. The total non-α-1,4 linkages in the pyrodextrin were about 17.8% compared to 5.8% in a maltodextrin prepared by α-amylase digestion. Transglycosidation and depolymerization occurred during dextrinization, and the resulting pyrodextrin was highly branched.

  7. High-pressure magic angle spinning nuclear magnetic resonance

    Science.gov (United States)

    Hoyt, David W.; Turcu, Romulus V. F.; Sears, Jesse A.; Rosso, Kevin M.; Burton, Sarah D.; Felmy, Andrew R.; Hu, Jian Zhi

    2011-10-01

    A high-pressure magic angle spinning (MAS) NMR capability, consisting of a reusable high-pressure MAS rotor, a high-pressure rotor loading/reaction chamber for in situ sealing and re-opening of the high-pressure MAS rotor, and a MAS probe with a localized RF coil for background signal suppression, is reported. The unusual technical challenges associated with development of a reusable high-pressure MAS rotor are addressed in part by modifying standard ceramics for the rotor sleeve by abrading the internal surface at both ends of the cylinder. In this way, not only is the advantage of ceramic cylinders for withstanding very high-pressure utilized, but also plastic bushings can be glued tightly in place so that other removable plastic sealing mechanisms/components and O-rings can be mounted to create the desired high-pressure seal. Using this strategy, sealed internal pressures exceeding 150 bars have been achieved and sustained under ambient external pressure with minimal loss of pressure for 72 h. As an application example, in situ13C MAS NMR studies of mineral carbonation reaction intermediates and final products of forsterite (Mg 2SiO 4) reacted with supercritical CO 2 and H 2O at 150 bar and 50 °C are reported, with relevance to geological sequestration of carbon dioxide.

  8. Application of nuclear magnetic resonance to the determination of the configuration of glycoside bond%核磁共振法在苷键构型确定中的应用

    Institute of Scientific and Technical Information of China (English)

    裴月湖; 华会明; 李占林; 陈刚

    2011-01-01

    天然苷类化合物结构测定过程中核磁共振是测定苷键构型的重要方法.利用端基质子的偶合常数和端基碳的化学位移值判断苷键构型是最常用的方法,但有些糖不适用这种方法,而需要借助13CNMR谱数据分析确定苷键构型.本文通过归纳文献数据,总结利用1H NMR和13C NMR谱的特征判断各种常见单糖苷键构型的方法.%In the structural determination of natural glycosides, nuclear magnetic resonance (NMR) is an important approach in determining the configuration of glycoside bond. The test of coupling constant of the anomeric proton and chemical shift of the anomeric carbon are two common methods, but these methods are not suitable for some sugars. For those sugars, detailed 13C NMR analysis is an altemative choice. This paper summarizes the characteristics of 1H and 13C NMR data of the common monosaccharides published in the literatures, in order to search an approach to determine the configuration of glycoside bond.

  9. (129) Xe and (131) Xe nuclear magnetic dipole moments from gas phase NMR spectra.

    Science.gov (United States)

    Makulski, Włodzimierz

    2015-04-01

    (3) He, (129) Xe and (131) Xe NMR measurements of resonance frequencies in the magnetic field B0=11.7586 T in different gas phase mixtures have been reported. Precise radiofrequency values were extrapolated to the zero gas pressure limit. These results combined with new quantum chemical values of helium and xenon nuclear magnetic shielding constants were used to determine new accurate nuclear magnetic moments of (129) Xe and (131) Xe in terms of that of the (3) He nucleus. They are as follows: μ((129) Xe) = -0.7779607(158)μN and μ((131) Xe) = +0.6918451(70)μN . By this means, the new 'helium method' for estimations of nuclear dipole moments was successfully tested. Gas phase NMR spectra demonstrate the weak intermolecular interactions observed on the (3) He and (129) Xe and (131) Xe shielding in the gaseous mixtures with Xe, CO2 and SF6 .

  10. Time-course metabolic changes in high-fat diet-induced obesity rats: A pilot study using hyperpolarized (13)C dynamic MRS.

    Science.gov (United States)

    Kim, Gwang-Won; Ahn, Kyu-Youn; Kim, Yun-Hyeon; Jeong, Gwang-Woo

    2016-10-01

    The purpose of this study was to investigate the time-course metabolic changes based on hyperpolarized (13)C magnetic resonance spectroscopy (MRS) in high-fat diet (HFD)-induced obesity rats and the correlation between metabolic and serum enzyme levels. Sprague-Dawley rats were fed either HFD (60% fat) or normal diet (10% fat) for 6weeks. A HyperSense DNP was used to hyperpolarize [1-(13)C] pyruvic acid and the hyperpolarized (13)C MRS was examined every 2weeks in the course of 6weeks using a 3T GE MR750 scanner. The body weight of HFD-induced obese rats was significantly increased compared to normal rats at the 6th week after the onset of feeding (p=0.05). Simultaneously, the HFD-induced obese rats showed significantly increased levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and low-density lipoprotein (LDL)-cholesterol compared to normal rats (p≤0.05). In the dynamic (13)C MR spectra acquired at the 6th week, the obese rats showed significantly increased ratios of [1-(13)C] lactate/[1-(13)C] pyruvate and [1-(13)C] alanine/[1-(13)C] pyruvate (p=0.05). The (13)C spectral outcomes are positively correlated with the enzyme levels of ALT and LDH in the HFD-induced obesity. The [1-(13)C] lactate and [1-(13)C] alanine are potentially considered as noninvasive biomarkers for the HFD-induced obesity.

  11. Nuclear structure in strong magnetic fields: nuclei in the crust of a magnetar

    CERN Document Server

    Arteaga, Daniel Pena; Khan, Elias; Ring, Peter

    2011-01-01

    Covariant density functional theory is used to study the effect of strong magnetic fields, up to the limit predicted for neutron stars (for magnetars $B \\approx10^{18}$G), on nuclear structure. All new terms in the equation of motion resulting from time reversal symmetry breaking by the magnetic field and the induced currents, as well as axial deformation, are taken into account in a self-consistent fashion. For nuclei in the iron region of the nuclear chart it is found that fields in the order of magnitude of $10^{17}$G significantly affect bulk properties like masses and radii.

  12. Anomalous hyperfine coupling and nuclear magnetic relaxation in Weyl semimetals

    Science.gov (United States)

    Okvátovity, Zoltán; Simon, Ferenc; Dóra, Balázs

    2016-12-01

    The electron-nuclear hyperfine interaction shows up in a variety of phenomena including, e.g., NMR studies of correlated states and spin decoherence effects in quantum dots. Here we focus on the hyperfine coupling and the NMR spin relaxation time T1 in Weyl semimetals. Since the density of states in Weyl semimetals varies with the square of the energy around the Weyl point, a naive power counting predicts a 1 /T1T ˜E4 scaling, with E the maximum of temperature (T ) and chemical potential. By carefully investigating the hyperfine interaction between nuclear spins and Weyl fermions, we find that while its spin part behaves conventionally, its orbital part diverges unusually, with the inverse of the energy around the Weyl point. Consequently, the nuclear spin relaxation rate scales in a graphenelike manner as 1 /T1T ˜E2ln(E /ω0) , with ω0 the nuclear Larmor frequency. This allows us to identify an effective hyperfine coupling constant, which is tunable by gating or doping. This is relevant for the decoherence effect in spintronics devices and double quantum dots, where hyperfine coupling is the dominant source of spin-blockade lifting.

  13. Nuclear magnetic resonance study of pure and Ni/Co doped LiFeAs

    Energy Technology Data Exchange (ETDEWEB)

    Grafe, Hans-Joachim; Baek, Seung-Ho; Hammerath, Franziska; Graefe, Uwe; Utz, Yannic; Harnagea, L.; Nacke, Claudia; Aswartham, Saicharan; Wurmehl, Sabine; Buechner, Bernd [Leibniz-Institut fuer Festkoerper- und Werkstoffforschung, Dresden (Germany)

    2011-07-01

    We present Nuclear Magnetic and Nuclear Quadrupole Resonance (NMR/NQR) measurements on pure, Ni and Co doped LiFeAs single crystals. The parent compound LiFeAs exhibits unconventional superconductivity with a transition temperature of about 17 K. Unlike other Fe based superconductors, where superconductivity is induced or stabilized by Co or Ni doping, replacement of Fe by these elements leads to a suppression of the superconducting transition temperature in LiFeAs. In case of Ni doping, a bulk magnetic order is induced below about 160 K. In contrast, for Co doping, the superconducting transition temperature is only reduced, but no magnetic order is observed. We discuss the nature and the origin of this magnetic order and its relation to unconventional superconductivity in pure LiFeAs.

  14. Zero and Ultra-Low-Field Nuclear Magnetic Resonance Spectroscopy Via Optical Magnetometry

    Science.gov (United States)

    Blanchard, John Woodland

    Nuclear magnetic resonance (NMR) is among the most powerful analytical tools available to the chemical and biological sciences for chemical detection, characterization, and structure elucidation. NMR experiments are usually performed in large magnetic fields in order to maximize sensitivity and increase chemical shift resolution. However, the high magnetic fields required for conventional NMR necessitate large, immobile, and expensive superconducting magnets, limiting the use of the technique. New hyperpolarization and non-inductive detection methods have recently allowed for NMR measurements in the inverse regime of extremely low magnetic fields. Whereas a substantial body of research has been conducted in the high-field regime, taking advantage of the efficient coherent control afforded by a spectroscopy dominated by coupling to the spectrometer, the zero- and ultra-low-field (ZULF) regime has remained mostly unexplored. In this dissertation, we investigate the applicability of ZULF-NMR as a novel spectroscopic technique complimentary to high-field NMR. In particular, we consider various aspects of the ZULF-NMR experiment and the dynamics of nuclear spins under various local spin coupling Hamiltonians. We first survey zero-field NMR experiments on systems dominated by the electron-mediated indirect spin-spin coupling (J-coupling). The resulting J-spectra permit precision measurement of chemically relevant information due to the exquisite sensitivity of J-couplings to subtle changes in molecular geometry and electronic structure. We also consider the effects of weak magnetic fields and residual dipolar couplings in anisotropic media, which encode information about nuclear magnetic moments and geometry, and further resolve topological ambiguities by lifting degeneracies. By extending the understanding of the interactions that contribute to ZULF-NMR spectra, this work represents a significant advancement towards a complete description of zero- and ultra

  15. High Resolution Magic Angle Spinning Nuclear Magnetic Resonance (HRMAS NMR) for Studies of Reactive Fabrics

    Science.gov (United States)

    2015-11-01

    Magnetic Resonance (HRMAS NMR) for Studies of Reactive Fabrics 5a. CONTRACT NUMBER W911SR-11-C-0047 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...ECBC-TR-1326 HIGH RESOLUTION MAGIC ANGLE SPINNING NUCLEAR MAGNETIC RESONANCE (HRMAS NMR) FOR STUDIES OF REACTIVE FABRICS David J. McGarvey...unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT An analytical chemistry method is described for measuring the reactivity and permeation of

  16. Surface chemistry of group 11 atomic layer deposition precursors on silica using solid-state nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Pallister, Peter J.; Barry, Seán T.

    2017-02-01

    The use of chemical vapour deposition (CVD) and atomic layer deposition (ALD) as thin film deposition techniques has had a major impact on a number of fields. The deposition of pure, uniform, conformal thin films requires very specific vapour-solid reactivity that is largely unknown for the majority of ALD and CVD precursors. This work examines the initial chemisorption of several thin film vapour deposition precursors on high surface area silica (HSAS) using 13C, 31P, and quantitative 29Si nuclear magnetic resonance spectroscopy (NMR). Two copper metal precursors, 1,3-diisopropyl-imidazolin-2-ylidene copper (I) hexamethyldisilazide (1) and 1,3-diethyl-imidazolin-2-ylidene copper(I) hexamethyldisilazide (2), and one gold metal precursor, trimethylphosphine gold(III) trimethyl (3), are examined. Compounds 1 and 2 were found to chemisorb at the hydroxyl surface-reactive sites to form a ||-O-Cu-NHC surface species and fully methylated silicon (||-SiMe3, due to reactivity of the hexamethyldisilazane (HMDS) ligand on the precursor) at 150 °C and 250 °C. From quantitative 29Si solid-state NMR (SS-NMR) spectroscopy measurements, it was found that HMDS preferentially reacts at geminal disilanol surface sites while the copper surface species preferentially chemisorbed to lone silanol surface species. Additionally, the overall coverage was strongly dependent on temperature, with higher overall coverage of 1 at higher temperature but lower overall coverage of 2 at higher temperature. The chemisorption of 3 was found to produce a number of interesting surface species on HSAS. Gold(III) trimethylphosphine, reduced gold phosphine, methylated phosphoxides, and graphitic carbon were all observed as surface species. The overall coverage of 3 on HSAS was only about 10% at 100 °C and, like the copper compounds, had a preference for lone silanol surface reactive sites. The overall coverage and chemisorbed surface species have implications to the overall growth rate and purity of

  17. Monte Carlo Simulation of Adiabatic Cooling and Nuclear Magnetism

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker; Viertiö, H. E.; Mouritsen, Ole G.

    1988-01-01

    constant-temperature or constant-magnetic-field quenches into the antiferromagnetic phase is found at late times to obey the classical Allen-Cahn growth law. The qualitative features of isentropic quenches and the nonequilibrium ordering phenomena during controlled heating treatments at constant rate...

  18. Approaches to studies on neuronal/glial relationships by 13C-MRS analysis.

    Science.gov (United States)

    Taylor, A; McLean, M; Morris, P; Bachelard, H

    1996-01-01

    The use of different 13C-labelled precursors alone or in combination ([1-13C]glucose, [2-13C]glucose, [1-13C]acetate, [2-13C]acetate and [1,2-13C2]acetate) to study neuronal/glial metabolic relationships by MRS is discussed. Glutamine and citrate resonances represent glial metabolism if a combination of [1-13C]glucose + [2-13C]acetate is used, but only for short time periods. A combination of [2-13C]glucose + [2-13C]acetate will label -COO- groups from glucose and -CH2 groups from acetate, respectively, which distinguish well in theory. However, this approach is severely limited by the long T1S of -COO- groups and low S/N. Contributions of the anaplerotic pathway can be assessed using [2-13C]glucose, but again can be limited by the long T1S of -COO- groups. Labelling of glycerol-3-phosphate (believed to be produced in glia) from [1-13C]glucose is difficult to see under normal conditions but has proved useful in, e.g., hypoxia. We believe the most promising approach is the use of [1-13C] glucose with [1,2-13C2]acetate, by analysis of the multiplets ('isotopomers') of the amino acid resonances.

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

    Science.gov (United States)

    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

  20. The First in Vivo Observation of 13C- 15N Coupling in Mammalian Brain

    Science.gov (United States)

    Kanamori, Keiko; Ross, Brian D.

    2001-12-01

    [5-13C,15N]Glutamine, with 1J(13C-15N) of 16 Hz, was observed in vivo in the brain of spontaneously breathing rats by 13C MRS at 4.7 T. The brain [5-13C]glutamine peak consisted of the doublet from [5-13C,15N]glutamine and the center [5-13C,14N]glutamine peak, resulting in an apparent triplet with a separation of 8 Hz. The time course of formation of brain [5-13C,15N]glutamine was monitored in vivo with a time resolution of 20-35 min. This [5-13C,15N]glutamine was formed by glial uptake of released neurotransmitter [5-13C]glutamate and its reaction with 15NH3 catalyzed by the glia-specific glutamine synthetase. The neurotransmitter glutamate C5 was selectively13C-enriched by intravenous [2,5-13C]glucose infusion to 13C-label whole-brain glutamate C5, followed by [12C]glucose infusion to chase 13C from the small and rapidly turning-over glial glutamate pool, leaving 13C mainly in the neurotransmitter [5-13C]glutamate pool, which is sequestered in vesicles until release. Hence, the observed [5-13C,15N]glutamine arises from a coupling between 13C of neuronal origin and 15N of glial origin. Measurement of the rate of brain [5-13C,15N]glutamine formation provides a novel noninvasive method of studying the kinetics of neurotransmitter uptake into glia in vivo, a process that is crucial for protecting the brain from glutamate excitotoxicity.

  1. Microwave spectra for the three 13C1 isotopologues of propene and new rotational constants for propene and its 13C1 isotopologues

    Science.gov (United States)

    Craig, Norman C.; Groner, Peter; Conrad, Andrew R.; Gurusinghe, Ranil; Tubergen, Michael J.

    2016-10-01

    New measurements of microwave lines (A and E) of propene and its three 13C1 isotopologues have been made in the 10-22 GHz region with FT accuracy. The revised lines for propene along with many hundreds from the literature were fitted with the ERHAM program for internal rotors to give improved rotational constants. The new constants are A0 = 46280.2904(16), B0 = 9305.24260(30), and C0 = 8134.22685(28) MHz. Lines for the 3-13C1 species were observed in a pure sample; lines for the 1-13C1 and 2-13C1 species were observed in natural abundance. In fitting the limited sets of lines for the 13C1 species, many of the centrifugal distortion constants and most of the tunneling parameters were transferred from the fit of propene itself with 27 parameters. Improved rotational constants for the 13C1 species are reported.

  2. Quantitative importance of the pentose phosphate pathway determined by incorporation of 13C from [2-13C]- and [3-13C]glucose into TCA cycle intermediates and neurotransmitter amino acids in functionally intact neurons

    DEFF Research Database (Denmark)

    Brekke, Eva Marie; Walls, Anne Byriel; Schousboe, Arne

    2012-01-01

    is known about the PPP in neurons. The activity of the PPP was quantified in cultured cerebral cortical and cerebellar neurons after incubation in the presence of [2-(13)C]glucose or [3-(13)C]glucose. The activity of the PPP was several fold lower than glycolysis in both types of neurons. While metabolism...

  3. High-pass bird-cage coil for nuclear-magnetic resonance

    Science.gov (United States)

    Watkins, Joel C.; Fukushima, Eiichi

    1988-06-01

    Cylindrical bird-cage coils generate uniform magnetic fields transverse to the cylinder axis for use in the large sample nuclear-magnetic resonance (NMR) experiments. We describe the design and construction of an eight-rung high-pass bird-cage coil to operate at 80 MHz in a cylindrical bore of a superconducting magnet. The coil is 12.7 cm in diameter by 30.5 cm long and has a 7-cm-diam region in the center where the field intensity is within 10% of the average.

  4. 13C NMR DETERMINATION OF EIGHT BENZO[h]QUINOLINES%8种苯并[h]喹啉的13C NMR归属

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    报道了8种新的苯并[h]喹啉的13C NMR谱.应用13C NMR等谱确定了这8种新化合物的分子结构,并对全部谱峰进行了归属,初步探讨了分子结构对13C NMR化学位移的影响.

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

    Science.gov (United States)

    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.

  6. Biosynthesis of highly enriched 13C-lycopene for human metabolic studies using repeated batch tomato cell culturing with 13C-glucose

    OpenAIRE

    Moran, Nancy E.; Rogers, Randy B.; Lu, Chi-Hua; Conlon, Lauren E.; Lila, Mary Ann; Clinton, Steven K.; Erdman, John W

    2013-01-01

    While putative disease-preventing lycopene metabolites are found in both tomato (Solanum lycopersicum) products and in their consumers, mammalian lycopene metabolism is poorly understood. Advances in tomato cell culturing techniques offer an economical tool for generation of highly-enriched 13C-lycopene for human bioavailability and metabolism studies. To enhance the 13C-enrichment and yields of labeled lycopene from the hp-1 tomato cell line, cultures were first grown in 13C-glucose media fo...

  7. IRMS detection of testosterone manipulated with {sup 13}C labeled standards in human urine by removing the labeled {sup 13}C

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jingzhu, E-mail: wangjingzhu@chinada.cn [National Anti-Doping Laboratory, China Anti-Doping Agency, Beijing (China); Yang, Rui [Sport Science College, Beijing Sport University Beijing, Beijing (China); Yang, Wenning [School of Pharmacy, Beijing University of Chinese Medicine, Beijing (China); Liu, Xin; Xing, Yanyi; Xu, Youxuan [National Anti-Doping Laboratory, China Anti-Doping Agency, Beijing (China)

    2014-12-10

    Highlights: • {sup 13}C labeled testosterone can be used to adjust the isotope ratio of testosterone. • The novel testosterone cannot be detected by the regular IRMS method in doping test. • A method was explored to remove the labeled {sup 13}C. • The established method can be used to detect the manipulated testosterone. - Abstract: Isotope ratio mass spectrometry (IRMS) is applied to confirm testosterone (T) abuse by determining the carbon isotope ratios (δ{sup 13}C value). However, {sup 13}C labeled standards can be used to control the δ{sup 13}C value and produce manipulated T which cannot be detected by the current method. A method was explored to remove the {sup 13}C labeled atom at C-3 from the molecule of androsterone (Andro), the metabolite of T in urine, to produce the resultant (A-nor-5α-androstane-2,17-dione, ANAD). The difference in δ{sup 13}C values between Andro and ANAD (Δδ{sup 13}C{sub Andro–ANAD}, ‰) would change significantly in case manipulated T is abused. Twenty-one volunteers administered T manipulated with different {sup 13}C labeled standards. The collected urine samples were analyzed with the established method, and the maximum value of Δδ{sup 13}C{sub Andro–ANAD} post ingestion ranged from 3.0‰ to 8.8‰. Based on the population reference, the cut-off value of Δδ{sup 13}C{sub Andro–ANAD} for positive result was suggested as 1.2‰. The developed method could be used to detect T manipulated with 3-{sup 13}C labeled standards.

  8. Hyperpolarized [1,3-13C2 ]ethyl acetoacetate is a novel diagnostic metabolic marker of liver cancer.

    Science.gov (United States)

    Jensen, Pernille R; Serra, Sonia Colombo; Miragoli, Luigi; Karlsson, Magnus; Cabella, Claudia; Poggi, Luisa; Venturi, Luca; Tedoldi, Fabio; Lerche, Mathilde H

    2015-02-15

    An increased prevalence of liver diseases such as hepatitis C and nonalcoholic fatty liver results in an augmented incidence of the most common form of liver cancer, hepatocellular carcinoma (HCC). HCC is most often found in the cirrhotic liver and it can therefore be challenging to rely on anatomical information alone when diagnosing HCC. Valuable information on specific cellular metabolism can be obtained with high sensitivity thanks to an emerging magnetic resonance (MR) technique that uses 13C labeled hyperpolarized molecules. Our interest was to explore potential new high contrast metabolic markers of HCC using hyperpolarized 13C-MR. This work led to the identification of a class of substrates, low molecular weight ethyl-esters, which showed high specificity for carboxyl esterases and proved in many cases to possess good properties for signal enhancement. In particular, hyperpolarized [1,3-13C2 ]ethyl acetoacetate (EAA) was shown to provide a metabolic fingerprint of HCC. Using this substrate a liver cancer implanted in rats was diagnosed as a consequence of an ∼4 times higher metabolic substrate-to-product ratio than in the surrounding healthy tissue, (p=0.009). Unregulated cellular uptake as well as cosubstrate independent enzymatic conversion of EAA, made this substrate highly useful as a hyperpolarized 13C-MR marker. This could be appreciated by the signal-to-noise (SNR) obtained from EAA, which was comparable to the SNR reported in a literature liver cancer study with state-of-the-art hyperpolarized substrate, [1-13C]pyruvate. Also, the contrast-to-noise (CNR) in the EAA based metabolic ratio images was significantly improved compared with the CNR in equivalent images reported using [1-13C]pyruvate.

  9. s-PROCESSING IN AGB STARS REVISITED. II. ENHANCED {sup 13}C PRODUCTION THROUGH MHD-INDUCED MIXING

    Energy Technology Data Exchange (ETDEWEB)

    Trippella, O.; Busso, M.; Palmerini, S.; Maiorca, E. [Department of Physics, University of Perugia, and INFN, Section of Perugia, via A. Pascoli, I-06123 Perugia (Italy); Nucci, M. C., E-mail: oscar.trippella@fisica.unipg.it [Department of Mathematics and Informatics, University of Perugia, via Vanvitelli, I-06123 Perugia and INFN, Section of Perugia, via A. Pascoli, I-06123 Perugia (Italy)

    2016-02-20

    Slow neutron captures are responsible for the production of about 50% of elements heavier than iron, mainly occurring during the asymptotic giant branch phase of low-mass stars (1 ≲ M/M{sub ⊙} ≲ 3), where the main neutron source is the {sup 13}C(α, n){sup 16}O reaction. This last reaction is activated from locally produced {sup 13}C, formed by partial mixing of hydrogen into the He-rich layers. We present here the first attempt to describe a physical mechanism for the formation of the {sup 13}C reservoir, studying the mass circulation induced by magnetic buoyancy without adding new free parameters to those already involved in stellar modeling. Our approach represents the application to the stellar layers relevant for s-processing of recent exact analytical 2D and 3D models for magneto-hydrodynamic processes at the base of convective envelopes in evolved stars in order to promote downflows of envelope material for mass conservation during the occurrence of a dredge-up phenomenon. We find that the proton penetration is characterized by small concentrations, but is extended over a large fractional mass of the He-layers, thus producing {sup 13}C reservoirs of several 10{sup −3} M{sub ⊙}. The ensuing {sup 13}C-enriched zone has an almost flat profile, while only a limited production of {sup 14}N occurs. In order to verify the effects of our new findings we show how the abundances of the main s-component nuclei can be accounted for in solar proportions and how our large {sup 13}C-reservoir allows us to solve a few so far unexplained features in the abundance distribution of post-AGB objects.

  10. Effect of ionic interaction between a hyperpolarized magnetic resonance chemical probe and a gadolinium contrast agent for the hyperpolarized lifetime after dissolution

    Science.gov (United States)

    Takakusagi, Yoichi; Inoue, Kaori; Naganuma, Tatsuya; Hyodo, Fuminori; Ichikawa, Kazuhiro

    2016-09-01

    In hyperpolarization of 13C-enriched magnetic resonance chemical probes in the solid-state, a trace amount of gadolinium (Gd) contrast agent can be used to maximize polarization of the 13C nuclear spins. Here, we report systematic measurement of the spin-lattice relaxation time (T1) and enhancement level of 13C-enriched chemical probes in the presence of various Gd contrast agents in the liquid-state after dissolution. Using two different 13C probes having opposite electric charges at neutral pH, we clearly show the T1 of hyperpolarized 13C was barely affected by the use of a Gd complex that displays repulsive interaction with the 13C probe in solution, whilst T1 was drastically shortened when there was ionic attraction between probe and complex.

  11. Analytical model for relativistic corrections to the nuclear magnetic shielding constant in atoms

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Rodolfo H. [Facultad de Ciencias Exactas, Universidad Nacional del Nordeste, Avenida Libertad 5500 (3400), Corrientes (Argentina)]. E-mail: rhromero@exa.unne.edu.ar; Gomez, Sergio S. [Facultad de Ciencias Exactas, Universidad Nacional del Nordeste, Avenida Libertad 5500 (3400), Corrientes (Argentina)

    2006-04-24

    We present a simple analytical model for calculating and rationalizing the main relativistic corrections to the nuclear magnetic shielding constant in atoms. It provides good estimates for those corrections and their trends, in reasonable agreement with accurate four-component calculations and perturbation methods. The origin of the effects in deep core atomic orbitals is manifestly shown.

  12. In vivo imaging of the rat anatomy with nuclear magnetic resonance.

    Science.gov (United States)

    Hansen, G; Crooks, L E; Davis, P; De Groot, J; Herfkens, R; Margulis, A R; Gooding, C; Kaufman, L; Hoenninger, J; Arakawa, M; McRee, R; Watts, J

    1980-09-01

    Live rats were imaged by nuclear magnetic resonance (NMR). These images demonstrated fine detail and high object contrast. Motion artifacts are not apparent in 4-minute images, and major blood vessels are demonstrated as regions of low signal intensity because of blood flow. Selective contrast enhancement is possible by varying NMR imager accumulation parameters.

  13. A New Density Operator Formalism for Describing Nuclear Magnetic Resonance Experiments

    Institute of Scientific and Technical Information of China (English)

    林东海; 吴钦义

    1994-01-01

    A density operator formalism has been proposed to describe the evolution of two-spin-1/2 systems in nuclear magnetic resonance experiments:The formalism is particularly convenient and has distinct physical meaning for describing the evolution of spin systems under the Hamiltonian containing non-commutable terms. Some examples are presented to demonstrate the new formalism.

  14. Nuclear magnetic resonance spectroscopy of living systems : Applications in comparative physiology

    NARCIS (Netherlands)

    VanDenThillart, G; VanWaarde, A

    The most attractive feature of nuclear magnetic resonance spectroscopy (MRS) is the noninvasive and nondestructive measurement of chemical compounds in intact tissues. MRS already has many applications in comparative physiology, usually based on observation of P-31, since the levels of phosphorus

  15. 19F-nuclear magnetic resonance spectroscopy as a tool to ...

    African Journals Online (AJOL)

    Purpose: 19F-Nuclear magnetic resonance spectroscopy (19F-NMR) was used to study host-guest ... least-squares curve fitting program, KINFIT, to obtain the formation constant of CD-drug complex. ..... It is interesting to note that, methylated.

  16. Sealed magic angle spinning nuclear magnetic resonance probe and process for spectroscopy of hazardous samples

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Herman M.; Washton, Nancy M.; Mueller, Karl T.; Sears, Jr., Jesse A.; Townsend, Mark R.; Ewing, James R.

    2016-06-14

    A magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) probe is described that includes double containment enclosures configured to seal and contain hazardous samples for analysis. The probe is of a modular design that ensures containment of hazardous samples during sample analysis while preserving spin speeds for superior NMR performance and convenience of operation.

  17. Study of coals by high resolution solid state nuclear magnetic resonance

    Institute of Scientific and Technical Information of China (English)

    杨保联; 冯继文; 周建威; 李丽云; 叶朝辉

    1999-01-01

    By using high resolution solid state nuclear magnetic resonance method, six coal samples coming from four countries were investigated. Twelve structural parameters of these samples were measured and compared with those of Chinese coals. Spectral editing experiment was carried out and 15N NMR spectrum was obtained.

  18. Towards nuclear magnetic resonance micro-spectroscopy and micro-imaging.

    NARCIS (Netherlands)

    Bentum, P.J.M. van; Janssen, J.W.G.; Kentgens, A.P.M.

    2004-01-01

    The first successful experiments demonstrating Nuclear Magnetic Resonance (NMR) were a spin-off from the development of electromagnetic technology and its introduction into civilian life in the late forties. It was soon discovered that NMR spectra held chemically relevant information making it usefu

  19. Nuclear Magnetic Resonance and Elastic Wave Velocity of Chalk Saturated with Brines Containing Divalent Ions

    DEFF Research Database (Denmark)

    Katika, Konstantina; Alam, Mohammad Monzurul; Fabricius, Ida Lykke

    Nuclear magnetic resonance (NMR) has proven a good technique for measuring pore size distribution in reservoir rocks. The use of low field NMR together with sonic and electrical resistivity measurements, can contribute to illustrate the effect of adsorbing ions on chalk elasticity. NMR is useful...

  20. Phosphorus-doped thin silica films characterized by magic-angle spinning nuclear magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Jacobsen, H.J.; Skibsted, J.; Kristensen, Martin

    2001-01-01

    Magic-angle spinning nuclear magnetic resonance spectra of 31P and 29Si have been achieved for a thin silica film doped with only 1.8% 31P and deposited by plasma enhanced chemical vapor deposition on a pure silicon wafer. The observation of a symmetric 31P chemical shift tensor is consistent...

  1. Nuclear magnetic resonance and sound velocity measurements of chalk saturated with magnesium rich brine

    DEFF Research Database (Denmark)

    Katika, Konstantina; Alam, Mohammad Monzurul; Fabricius, Ida Lykke

    2013-01-01

    The use of low field Nuclear Magnetic Resonance (NMR) to determine petrophysical properties of reservoirs has proved to be a good technique. Together with sonic and electrical resistivity measurements, NMR can contribute to illustrate the changes on chalk elasticity due to different pore water...

  2. A Noninvasive Method to Study Regulation of Extracellular Fluid Volume in Rats Using Nuclear Magnetic Resonance

    Science.gov (United States)

    Time-domain nuclear magnetic resonance (TD-NMR)-based measurement of body composition of rodents is an effective method to quickly and repeatedly measure proportions of fat, lean, and fluid without anesthesia. TD-NMR provides a measure of free water in a living animal, termed % f...

  3. 13C NMR relaxation studies on cartilage and cartilage components.

    Science.gov (United States)

    Naji, L; Kaufmann, J; Huster, D; Schiller, J; Arnold, K

    2000-08-07

    We have investigated the molecular motions of polysaccharides of bovine nasal and pig articular cartilage by measuring the 13C NMR relaxation times (T1 and T2). Both types of cartilage differ significantly towards their collagen/glycosaminoglycan ratio, leading to different NMR spectra. As chondroitin sulfate is the main constituent of cartilage, aqueous solutions of related poly- and monosaccharides (N-acetylglucosamine and glucuronic acid) were also investigated. Although there are only slight differences in T1 relaxation of the mono- and the polysaccharides, T2 decreases about one order of magnitude, when glucuronic acid or N-acetylglucosamine and chondroitin sulfate are compared. It is concluded that the ring carbons are motion-restricted primarily by the embedment in the rigid pyranose structure and, thus, additional limitations of mobility do not more show a major effect. Significant differences were observed between bovine nasal and pig articular cartilage, resulting in a considerable line-broadening and a lower signal to noise ratio in the spectra of pig articular cartilage. This is most likely caused by the higher collagen content of articular cartilage in comparison to the polysaccharide-rich bovine nasal cartilage.

  4. Inelastic pion scattering by /sup 13/C at low energies

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, J.H.

    1987-03-01

    Angular distributions for inelastically scattered pions were obtained for several states in /sup 13/C at an incident energy of 65 MeV. The data include results from both ..pi../sup +/ and ..pi../sup -/ measurements. In addition, ..pi../sup -/ measurements were made at T/sub ..pi../ = 50 MeV at one angle to give a two point fixed-q excitation function. The data are compared to theory and the data of others. As might be expected, medium corrections are shown to be considerably more important at low energies than at resonance. This is true for inelastic transitions of multipolarity 0,2 and 3. Parameters derived from an analysis of elastic pion scattering and SCX data also provide an adequate description of the inelastic transitions. The charge asymmetry in the cross sections for the 9/2/sup +/ state that was seen at resonance persists at these energies. This result is consistent with an impulse approximation treatment of the spin-flip amplitude. This is true even though the incoming energy of the pions is far below the range where the validity of an impulse treatment is expected. 65 refs., 45 figs.

  5. /sup 13/C NMR studies of the molecular flexibility of antidepressants

    Energy Technology Data Exchange (ETDEWEB)

    Munro, S.L.; Andrews, P.R.; Craik, D.J.; Gale, D.J.

    1986-02-01

    The solution dynamics of a series of clinically potent antidepressants have been investigated by measuring /sup 13/C NMR relaxation parameters. Correlation times and internal motional rates were calculated from spin-lattice relaxation times and nuclear Overhauser effects for the protonated carbons in mianserin, imipramine-like antidepressants, and amitriptyline-like antidepressants. These data were interpreted in terms of overall molecular tumbling, internal rotations, and inherent flexibility of these structures. Of particular interest was the conformational variability of the tricyclic nucleus of the tricyclic antidepressants, where the data indicated a fivefold difference in mobility of the dimethylene bridge of imipramine-like antidepressants relative to amitriptyline-like compounds. The implications of such a difference in internal motions is discussed in relation to previous NMR studies and to the reported differences in pharmacological activity of these antidepressants.

  6. Imaging of branched chain amino acid metabolism in tumors with hyperpolarized 13C ketoisocaproate.

    Science.gov (United States)

    Karlsson, Magnus; Jensen, Pernille R; in 't Zandt, René; Gisselsson, Anna; Hansson, Georg; Duus, Jens Ø; Meier, Sebastian; Lerche, Mathilde H

    2010-08-01

    Powerful analytical tools are vital for characterizing the complex molecular changes underlying oncogenesis and cancer treatment. This is particularly true, if information is to be collected in vivo by noninvasive approaches. In the recent past, hyperpolarized (13)C magnetic resonance (MR) spectroscopy has been employed to quickly collect detailed spectral information on the chemical fate of tracer molecules in different tissues at high sensitivity. Here, we report a preclinical study showing that alpha-ketoisocaproic acid (KIC) can be used to assess molecular signatures of tumors with hyperpolarized MR spectroscopy. KIC is metabolized to leucine by the enzyme branched chain amino acid transferase (BCAT), which is found upregulated in some tumors. BCAT is a putative marker for metastasis and a target of the proto-oncogene c-myc. Very different fluxes through the BCAT-catalyzed reaction can be detected for murine lymphoma (EL4) and rat mammary adenocarcinoma (R3230AC) tumors in vivo. EL4 tumors show a more than 7-fold higher hyperpolarized (13)C leucine signal relative to the surrounding healthy tissue. In R3230AC tumor on the other hand branched chain amino acid metabolism is not enhanced relative to surrounding tissues. The distinct molecular signatures of branched chain amino acid metabolism in EL4 and R3230AC tumors correlate well with ex vivo assays of BCAT activity.

  7. Remote detection of nuclear magnetic resonance with an anisotropic magnetoresistive sensor.

    Science.gov (United States)

    Verpillat, F; Ledbetter, M P; Xu, S; Michalak, D J; Hilty, C; Bouchard, L-S; Antonijevic, S; Budker, D; Pines, A

    2008-02-19

    We report the detection of nuclear magnetic resonance (NMR) using an anisotropic magnetoresistive (AMR) sensor. A "remote-detection" arrangement was used in which protons in flowing water were prepolarized in the field of a superconducting NMR magnet, adiabatically inverted, and subsequently detected with an AMR sensor situated downstream from the magnet and the adiabatic inverter. AMR sensing is well suited for NMR detection in microfluidic "lab-on-a-chip" applications because the sensors are small, typically on the order of 10 mum. An estimate of the sensitivity for an optimized system indicates that approximately 6 x 10(13) protons in a volume of 1,000 mum(3), prepolarized in a 10-kG magnetic field, can be detected with a signal-to-noise ratio of 3 in a 1-Hz bandwidth. This level of sensitivity is competitive with that demonstrated by microcoils in superconducting magnets and with the projected sensitivity of microfabricated atomic magnetometers.

  8. Origin of the magnetic-field dependence of the nuclear spin-lattice relaxation in iron

    CERN Document Server

    Seewald, G; Körner, H J; Borgmann, D; Dietrich, M

    2008-01-01

    The magnetic-field dependence of the nuclear spin-lattice relaxation at Ir impurities in Fe was measured for fields between 0 and 2 T parallel to the [100] direction. The reliability of the applied technique of nuclear magnetic resonance on oriented nuclei was demonstrated by measurements at different radio-frequency (rf) field strengths. The interpretation of the relaxation curves, which used transition rates to describe the excitation of the nuclear spins by a frequency-modulated rf field, was confirmed by model calculations. The magnetic-field dependence of the so-called enhancement factor for rf fields, which is closely related to the magnetic-field dependence of the spin-lattice relaxation, was also measured. For several magnetic-field-dependent relaxation mechanisms, the form and the magnitude of the field dependence were derived. Only the relaxation via eddy-current damping and Gilbert damping could explain the observed field dependence. Using reasonable values of the damping parameters, the field depe...

  9. 13C and 15N spectral editing inside histidine imidazole ring through solid-state NMR spectroscopy.

    Science.gov (United States)

    Li, Shenhui; Zhou, Lei; Su, Yongchao; Han, Bin; Deng, Feng

    2013-01-01

    Histidine usually exists in three different forms (including biprotonated species, neutral τ and π tautomers) at physiological pH in biological systems. The different protonation and tautomerization states of histidine can be characteristically determined by (13)C and (15)N chemical shifts of imidazole ring. In this work, solid-state NMR techniques were developed for spectral editing of (13)C and (15)N sites in histidine imidazole ring, which provides a benchmark to distinguish the existing forms of histidine. The selections of (13)Cγ, (13)Cδ2, (15)Nδ1, and (15)Nε2 sites were successfully achieved based on one-bond homo- and hetero-nuclear dipole interactions. Moreover, it was demonstrated that (1)H, (13)C, and (15) chemical shifts were roughly linearly correlated with the corresponding atomic charge in histidine imidazole ring by theoretical calculations. Accordingly, the (1)H, (13)C and (15)N chemical shifts variation in different protonation and tautomerization states could be ascribed to the atomic charge change due to proton transfer in biological process.

  10. The magnetic field dependence of cross-effect dynamic nuclear polarization under magic angle spinning

    Energy Technology Data Exchange (ETDEWEB)

    Mance, Deni; Baldus, Marc, E-mail: m.baldus@uu.nl [NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, 3584 CH Utrecht (Netherlands); Gast, Peter; Huber, Martina [Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO Box 9504, 2300 RA Leiden (Netherlands); Ivanov, Konstantin L., E-mail: ivanov@tomo.nsc.ru [International Tomography Center, Siberian Branch of the Russian Academy of Science, Institutskaya 3a, Novosibirsk 630090, Russia and Novosibirsk State University, Pirogova 2, Novosibirsk 63009 (Russian Federation)

    2015-06-21

    We develop a theoretical description of Dynamic Nuclear Polarization (DNP) in solids under Magic Angle Spinning (MAS) to describe the magnetic field dependence of the DNP effect. The treatment is based on an efficient scheme for numerical solution of the Liouville-von Neumann equation, which explicitly takes into account the variation of magnetic interactions during the sample spinning. The dependence of the cross-effect MAS-DNP on various parameters, such as the hyperfine interaction, electron-electron dipolar interaction, microwave field strength, and electron spin relaxation rates, is analyzed. Electron spin relaxation rates are determined by electron paramagnetic resonance measurements, and calculations are compared to experimental data. Our results suggest that the observed nuclear magnetic resonance signal enhancements provided by MAS-DNP can be explained by discriminating between “bulk” and “core” nuclei and by taking into account the slow DNP build-up rate for the bulk nuclei.

  11. (13)C and (19)F solid-state NMR and X-ray crystallographic study of halogen-bonded frameworks featuring nitrogen-containing heterocycles.

    Science.gov (United States)

    Szell, Patrick M J; Gabriel, Shaina A; Gill, Russell D D; Wan, Shirley Y H; Gabidullin, Bulat; Bryce, David L

    2017-03-01

    Halogen bonding is a noncovalent interaction between the electrophilic region of a halogen (σ-hole) and an electron donor. We report a crystallographic and structural analysis of halogen-bonded compounds by applying a combined X-ray diffraction (XRD) and solid-state nuclear magnetic resonance (SSNMR) approach. Single-crystal XRD was first used to characterize the halogen-bonded cocrystals formed between two fluorinated halogen-bond donors (1,4-diiodotetrafluorobenzene and 1,3,5-trifluoro-2,4,6-triiodobenzene) and several nitrogen-containing heterocycles (acridine, 1,10-phenanthroline, 2,3,5,6-tetramethylpyrazine, and hexamethylenetetramine). New structures are reported for the following three cocrystals, all in the P21/c space group: acridine-1,3,5-trifluoro-2,4,6-triiodobenzene (1/1), C6F3I3·C13H9N, 1,10-phenanthroline-1,3,5-trifluoro-2,4,6-triiodobenzene (1/1), C6F3I3·C12H8N2, and 2,3,5,6-tetramethylpyrazine-1,3,5-trifluoro-2,4,6-triiodobenzene (1/1), C6F3I3·C8H12N2. (13)C and (19)F solid-state magic-angle spinning (MAS) NMR is shown to be a convenient method to characterize the structural features of the halogen-bond donor and acceptor, with chemical shifts attributable to cocrystal formation observed in the spectra of both nuclides. Cross polarization (CP) from (19)F to (13)C results in improved spectral sensitivity in characterizing the perfluorinated halogen-bond donor when compared to conventional (1)H CP. Gauge-including projector-augmented wave density functional theory (GIPAW DFT) calculations of magnetic shielding constants, along with optimization of the XRD structures, provide a final set of structures in best agreement with the experimental (13)C and (19)F chemical shifts. Data for carbons bonded to iodine remain outliers due to well-known relativistic effects.

  12. Alkaline Hydrolysis/Polymerization of 2,4,6-Trinitrotoluene: Characterization of Products by 13C and 15N NMR

    Science.gov (United States)

    Thorn, K.A.; Thorne, P.G.; Cox, L.G.

    2004-01-01

    Alkaline hydrolysis has been investigated as a nonbiological procedure for the destruction of 2,4,6-trinitrotoluene (TNT) in explosives contaminated soils and munitions scrap. Nucleophilic substitutions of the nitro and methyl groups of TNT by hydroxide ion are the initial steps in the alkaline degradation of TNT. Potential applications of the technique include both in situ surface liming and ex situ alkaline treatment of contaminated soils. A number of laboratory studies have reported the formation of an uncharacterized polymeric material upon prolonged treatment of TNT in base. As part of an overall assessment of alkaline hydrolysis as a remediation technique, and to gain a better understanding of the chemical reactions underlying the hydrolysis/polymerization process, the soluble and precipitate fractions of polymeric material produced from the calcium hydroxide hydrolysis of unlabeled and 15N-labeled TNT were analyzed by elemental analysis and 13C and 15N nuclear magnetic resonance spectroscopy. Spectra indicated that reactions leading to polymerization included nucleophilic displacement of nitro groups by hydroxide ion, formation of ketone, carboxyl, alcohol, ether, and other aliphatic carbons, conversion of methyl groups to diphenyl methylene carbons, and recondensation of aromatic amines and reduced forms of nitrite, including ammonia and possibly hydroxylamine, into the polymer. Compared to the distribution of carbons in TNT as 14% sp 3- and 86% sp2-hybridized, the precipitate fraction from hydrolysis of unlabeled TNT contained 33% sp3- and 67% sp 2-hybridized carbons. The concentration of nitrogen in the precipitate was 64% of that in TNT. The 15N NMR spectra showed that, in addition to residual nitro groups, forms of nitrogen present in the filtrate and precipitate fractions include aminohydroquinone, primary amide, indole, imine, and azoxy, among others. Unreacted nitrite was recovered in the filtrate fraction. The toxicities and susceptibilities to

  13. Nuclear magnetic resonance relaxation and diffusion in the presence of internal gradients: the effect of magnetic field strength.

    Science.gov (United States)

    Mitchell, J; Chandrasekera, T C; Johns, M L; Gladden, L F; Fordham, E J

    2010-02-01

    It is known that internal magnetic field gradients in porous materials, caused by susceptibility differences at the solid-fluid interfaces, alter the observed effective Nuclear Magnetic Resonance transverse relaxation times T2,eff. The internal gradients scale with the strength of the static background magnetic field B0. Here, we acquire data at various magnitudes of B0 to observe the influence of internal gradients on T2-T2 exchange measurements; the theory discussed and observations made are applicable to any T2-T2 analysis of heterogeneous materials. At high magnetic field strengths, it is possible to observe diffusive exchange between regions of local internal gradient extrema within individual pores. Therefore, the observed exchange pathways are not associated with pore-to-pore exchange. Understanding the significance of internal gradients in transverse relaxation measurements is critical to interpreting these results. We present the example of water in porous sandstone rock and offer a guideline to determine whether an observed T2,eff relaxation time distribution reflects the pore size distribution for a given susceptibility contrast (magnetic field strength) and spin echo separation. More generally, we confirm that for porous materials T1 provides a better indication of the pore size distribution than T2,eff at high magnetic field strengths (B0>1 T), and demonstrate the data analysis necessary to validate pore size interpretations of T2,eff measurements.

  14. Paramagnetic 13C and 15N NMR analyses of the push and pull effects in cytochrome c peroxidase and Coprinus cinereus peroxidase variants: functional roles of highly conserved amino acids around heme.

    Science.gov (United States)

    Nonaka, Daisuke; Wariishi, Hiroyuki; Welinder, Karen G; Fujii, Hiroshi

    2010-01-12

    Paramagnetic (13)C and (15)N nuclear magnetic resonance (NMR) spectroscopy of heme-bound cyanide ((13)C(15)N) was applied to 11 cytochrome c peroxidase (CcP) and Coprinus cinereus peroxidase (CIP) mutants to investigate contributions to the push and pull effects of conserved amino acids around heme. The (13)C and (15)N NMR data for the distal His and Arg mutants indicated that distal His is the key amino acid residue creating the strong pull effect and that distal Arg assists. The mutation of distal Trp of CcP to Phe, the amino acid at this position in CIP, changed the push and pull effects so they resembled those of CIP, whereas the mutation of distal Phe of CIP to Trp changed this mutant to become CcP-like. The (13)C NMR shifts for the proximal Asp mutants clearly showed that the proximal Asp-His hydrogen bonding strengthens the push effect. However, even in the absence of a hydrogen bond, the push effect of proximal His in peroxidase is significantly stronger than in globins. Comparison of these NMR data with the compound I formation rate constants and crystal structures of these mutants showed that (1) the base catalysis of the distal His is more critical for rapid compound I formation than its acid catalysis, (2) the primary function of the distal Arg is to maintain the distal heme pocket in favor of rapid compound I formation via hydrogen bonding, and (3) the push effect is the major contributor to the differential rates of compound I formation in wild-type peroxidases.

  15. Fractional {sup 13}C enrichment of isolated carbons using [1-{sup 13}C]- or [2-{sup 13}C]-glucose facilitates the accurate measurement of dynamics at backbone C{sup {alpha}} and side-chain methyl positions in proteins

    Energy Technology Data Exchange (ETDEWEB)

    Lundstroem, Patrik [University of Toronto, Departments of Medical Genetics and Chemistry (Canada); Teilum, Kaare; Carstensen, Tommy [Lund University, Department of Biophysical Chemistry (Sweden); Bezsonova, Irina [University of Toronto, Department of Chemistry (Canada); Wiesner, Silke [University of Toronto, Department of Biochemistry (Canada); Hansen, D. Flemming [University of Toronto, Departments of Medical Genetics and Chemistry (Canada); Religa, Tomasz L. [Medical Research Council Centre for Protein Engineering (United Kingdom); Akke, Mikael [Lund University, Department of Biophysical Chemistry (Sweden); Kay, Lewis E. [University of Toronto, Departments of Medical Genetics and Chemistry (Canada)], E-mail: kay@pound.med.utoronto.ca

    2007-07-15

    A simple labeling approach is presented based on protein expression in [1-{sup 13}C]- or [2-{sup 13}C]-glucose containing media that produces molecules enriched at methyl carbon positions or backbone C{sup {alpha}} sites, respectively. All of the methyl groups, with the exception of Thr and Ile({delta}1) are produced with isolated {sup 13}C spins (i.e., no {sup 13}C-{sup 13}C one bond couplings), facilitating studies of dynamics through the use of spin-spin relaxation experiments without artifacts introduced by evolution due to large homonuclear scalar couplings. Carbon-{alpha} sites are labeled without concomitant labeling at C{sup {beta}} positions for 17 of the common 20 amino acids and there are no cases for which {sup 13}C{sup {alpha}}-{sup 13}CO spin pairs are observed. A large number of probes are thus available for the study of protein dynamics with the results obtained complimenting those from more traditional backbone {sup 15}N studies. The utility of the labeling is established by recording {sup 13}C R{sub 1{rho}} and CPMG-based experiments on a number of different protein systems.

  16. Fluxomers: a new approach for 13C metabolic flux analysis

    Directory of Open Access Journals (Sweden)

    Young Jamey D

    2011-08-01

    Full Text Available Abstract Background The ability to perform quantitative studies using isotope tracers and metabolic flux analysis (MFA is critical for detecting pathway bottlenecks and elucidating network regulation in biological systems, especially those that have been engineered to alter their native metabolic capacities. Mathematically, MFA models are traditionally formulated using separate state variables for reaction fluxes and isotopomer abundances. Analysis of isotope labeling experiments using this set of variables results in a non-convex optimization problem that suffers from both implementation complexity and convergence problems. Results This article addresses the mathematical and computational formulation of 13C MFA models using a new set of variables referred to as fluxomers. These composite variables combine both fluxes and isotopomer abundances, which results in a simply-posed formulation and an improved error model that is insensitive to isotopomer measurement normalization. A powerful fluxomer iterative algorithm (FIA is developed and applied to solve the MFA optimization problem. For moderate-sized networks, the algorithm is shown to outperform the commonly used 13CFLUX cumomer-based algorithm and the more recently introduced OpenFLUX software that relies upon an elementary metabolite unit (EMU network decomposition, both in terms of convergence time and output variability. Conclusions Substantial improvements in convergence time and statistical quality of results can be achieved by applying fluxomer variables and the FIA algorithm to compute best-fit solutions to MFA models. We expect that the fluxomer formulation will provide a more suitable basis for future algorithms that analyze very large scale networks and design optimal isotope labeling experiments.

  17. Structural properties of carbon nanotubes derived from 13C NMR

    KAUST Repository

    Abou-Hamad, E.

    2011-10-10

    We present a detailed experimental and theoretical study on how structural properties of carbon nanotubes can be derived from 13C NMR investigations. Magic angle spinning solid state NMR experiments have been performed on single- and multiwalled carbon nanotubes with diameters in the range from 0.7 to 100 nm and with number of walls from 1 to 90. We provide models on how diameter and the number of nanotube walls influence NMR linewidth and line position. Both models are supported by theoretical calculations. Increasing the diameter D, from the smallest investigated nanotube, which in our study corresponds to the inner nanotube of a double-walled tube to the largest studied diameter, corresponding to large multiwalled nanotubes, leads to a 23.5 ppm diamagnetic shift of the isotropic NMR line position δ. We show that the isotropic line follows the relation δ = 18.3/D + 102.5 ppm, where D is the diameter of the tube and NMR line position δ is relative to tetramethylsilane. The relation asymptotically tends to approach the line position expected in graphene. A characteristic broadening of the line shape is observed with the increasing number of walls. This feature can be rationalized by an isotropic shift distribution originating from different diamagnetic shielding of the encapsulated nanotubes together with a heterogeneity of the samples. Based on our results, NMR is shown to be a nondestructive spectroscopic method that can be used as a complementary method to, for example, transmission electron microscopy to obtain structural information for carbon nanotubes, especially bulk samples.

  18. Nuclear magnetic resonance on selected lithium based compounds

    Energy Technology Data Exchange (ETDEWEB)

    Rudisch, Christian

    2013-11-26

    This thesis presents the NMR measurements on the single crystals LiMnPO{sub 4} and Li{sub 0.9}FeAs. Therefore, the thesis is divided into two separated sections. The first part reports on the competitive next generation cathode material LiMnPO{sub 4} with a stable reversible capacity up to 145 mAh/g and a rather flat discharge voltage curve at 4.1 V. For the basic understanding of the material the magnetic properties have been investigated by a Li and P NMR study in the paramagnetic and antiferromagnetic phase. LiMnPO{sub 4} shows a strong anisotropy of the dipolar hyperfine coupling due to the strong local magnetic moments at the Mn site. The corresponding dipole tensor of the Li- and P-nuclei is fully determined by orientation and temperature dependent NMR experiments and compared to the calculated values from crystal structure data. Deviations of the experimentally determined values from the theoretical ones are discussed in terms of Mn disorder which could have an impact on the mobility of the Li ions. The disorder is corroborated by diffuse X-ray diffraction experiments which indicate a sh