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Sample records for state 13c nuclear

  1. Alpha Resonant States in 13C

    International Nuclear Information System (INIS)

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

    2011-01-01

    The 9 Be( 6 Li,d) 13 C reaction was used to investigate alpha resonant states in 13 C up to 15 MeV of excitation. The reaction was measured at a bombarding energy of 25.5 MeV employing the Sao Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion detection technique. An energy resolution of 50 keV was obtained. Several narrow alpha resonant states not previously measured were detected, in particular the one at the (3α+n) threshold populated by an L = 2 transfer, revealing a 9 Be+α component for the 1/2 - cluster state candidate at this threshold. Experimental angular distributions are presented in comparison with DWBA predictions.

  2. 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.

  3. 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.

  4. 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.

  5. Solid-state 13C NMR characterization of polyanilines

    International Nuclear Information System (INIS)

    Kaplan, S.

    1988-01-01

    13 C solid-state nuclear magnetic resonance measurements are reported for the leucoemeraldine base, emeraldine base, and emeraldine hydrochloride forms of polyaniline in order to characterize the structures of these three distinct polymers. Chemical shift assignments are facilitated by use of the cross-depolarization technique to distinguish carbons with and without directly bonded hydrogens. Comparison of the spectra of emeraldine base with those of leucoemeraldine base and air-oxidized leucoemeraldine (which partially converts to emeraldine base) establishes that emeraldine base is essentially an alternating copolymer of reduced 1A (-(C 6 H 4 )N(H)(C 6 H 4 )N(H)-) and oxidized 2A (-(C 6 H 4 )N double-bond(C 6 H 4 )double-bond N-) repeat units. The 8-12 ppm spectral line widths measured for both emeraldine base and leucoemeraldine base are attributed to local fluctuations in conformational and configurational geometries, a distribution in chain packing, and compositional defects. 13 C spin-echo measurements establish that the 60 ppM wide line from the conducting emeraldine hydrochloride is inhomogeneously broadened. It is postulated that this line width is due to local variations in charge density along the polymer backbone arising from polymer structural heterogeneity. 47 refs., 5 figs., 1 tab

  6. 13C nuclear magnetic resonance study of the complexation of calcium by taurine

    International Nuclear Information System (INIS)

    Irving, C.S.; Hammer, B.E.; Danyluk, S.S.; Klein, P.D.

    1980-01-01

    13 C Nuclear magnetic resonance chemical shifts, 1 J/sub c-c/ scalar coupling constants, spin-lattice relaxation times, and nuclear Overhauser effects were determined for taurine-[1, 2 13 C] and a taurine-[1 13 C] and taurine-[2 13 C] mixture in the presence and absence of calcium. Comparison of taurine titration shifts to values for related compounds reveals some unusual electronic properties of the taurine molecule. Stability constants of 1:1 calcium complexes with taurine zwitterions and anions, as well as their 13 C chemical shifts, were obtained by least squares analysis of titration curves measured in the presence of calcium. The stability constants of calcium-taurine complexes were significantly lower than previous values and led to estimates that only approximately one percent of intracellular calcium of mammalian myocardial cells would exist in a taurine complex

  7. Substitution effect in nuclear magnetic resonance of C-13: α methoxicyclohexanones

    International Nuclear Information System (INIS)

    Lopez Holland, M.A.G.

    1984-01-01

    Eletronic and steric interactions between the carbonyl and methoxyl groups in α-methoxicyclohexanones by H-1 and C-13 nuclear magnetic resonance spectroscopy (n.m.r) is studied. Interpretation of H-1 n.m.r measurements based on the carbonyl group anisotropy is made. The asigment of spectral lines to specific nuclear by Lanthanide Shift Reagent Experiments is confirmed. Interpretation of C-13 n.m.r. spectra with respect to molecular effects and emphirical relationships associated with the substituent was analysed. The C-13 chemical shift asignment by comparison with results of partially (SFORD) and fully decompled spectra and also by relating the measured chemical shift with values cited in the literature for similar compounds are made. A qualitative study using I.R. spectroscopy in attempt to evaluate the predominance of one the conformers of the studied compounds in solutions of n-hexan and chloroform is made. (M.J.C.) [pt

  8. 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.

  9. 12C(d,p) 13C reaction at Esub(d) = 30 MeV to the positive-parity states in 13C

    International Nuclear Information System (INIS)

    Ohnuma, H.; Hoshino, N.; Mikoshiba, O.

    1985-07-01

    The 12 C(d, p) 13 C reaction has been studied at Esub(d) = 30 MeV. All the known positive-parity states of 13 C below 10 MeV in excitation energy, including the 7/2 + and 9/2 + states, are observed in this reaction. The angular distributions for these positive-parity bound and unbound states are analyzed in CCBA frame work. The 13 C wave functions, which reproduce the resonant and non-resonant scattering of neutrons from 12 C, also give good accounts of the experimentally observed angular distributions and energy spectra of outgoing protons in the 12 C(d, p) 13 C reaction. In most cases the cross section magnitude and the angular distribution shape are primarily determined by the 0 + x j component, even if it is only a small fraction of the total wave function. An exception is the 7/2 + state, where the main contribution comes from the 2 + x dsub(5/2) component. The inclusion of the 4 + state in 12 C and the gsub(9/2) and gsub(7/2) neutron components in the n + 12 C system has very small effects on the low-spin states, but is indispensable for a good fit to the 7/2 + and 9/2 + angular distributions. The transitions to the negative-parity states, 1/2 1 - , 3/2 1 - , 5/2 - , 7/2 - and 1/2 3 - , are also observed experimentally, and analyzed by DWBA. (author)

  10. Correlation between the 12C+12C, 12C+13C, and 13C+13C fusion cross sections

    Science.gov (United States)

    Notani, M.; Esbensen, H.; Fang, X.; Bucher, B.; Davies, P.; Jiang, C. L.; Lamm, L.; Lin, C. J.; Ma, C.; Martin, E.; Rehm, K. E.; Tan, W. P.; Thomas, S.; Tang, X. D.; Brown, E.

    2012-01-01

    The fusion cross section for 12C+13C has been measured down to Ec.m.=2.6 MeV, at which the cross section is of the order of 20 nb. By comparing the cross sections for the three carbon isotope systems, 12C+12C, 12C+13C, and 13C+13C, it is found that the cross sections for 12C+13C and 13C+13C provide an upper limit for the fusion cross section of 12C+12C over a wide energy range. After calibrating the effective nuclear potential for 12C+12C using the 12C+13C and 13C+13C fusion cross sections, it is found that a coupled-channels calculation with the ingoing wave boundary condition (IWBC) is capable of predicting the major peak cross sections in 12C+12C. A qualitative explanation for this upper limit is provided by the Nogami-Imanishi model and by level density differences among the compound nuclei. It is found that the strong resonance found at 2.14 MeV in 12C+12C exceeds this upper limit by a factor of more than 20. The preliminary result from the most recent measurement shows a much smaller cross section at this energy, which agrees with our predicted upper limit.

  11. 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...... 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...

  12. Nuclear critical opalescence and the M1 form factors of 12C and 13C

    International Nuclear Information System (INIS)

    Delorme, J.; Figureau, A.; Guichon, P.

    1981-01-01

    It is shown that core polarization by the nuclear pion field has opposite effects on the M1 form factors of 12 C(15.11 MeV) and 13 C(g.s.). New data on 13 C are found to agree with this prediction and a common interpretation of the experiments is shown to be possible for the two nuclei in terms of critical opalescence. Discrimination from alternative explanations of the observed anomalies should await further experiments, especially photopion reactions. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    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 studied by high-resolution solid-state nuclear magnetic resonance (NMR) techniques. Dipolar dephasing /sup 13/C 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. 28 refs., 9 figs., 1 tab.

  14. Direct monitoring by carbon-13 nuclear magnetic resonance spectroscopy of the metabolism and metabolic rate of 13C-labeled compounds in vivo.

    Science.gov (United States)

    Iida, K; Hidoh, O; Fukami, J; Kajiwara, M

    1991-01-01

    Carbon-13 nuclear magnetic resonance spectroscopy has been used to observe the transformations of [1-13C]-D-glucose to [1,1'-13C2]-D-trehalose, and [3-13C]-L-alanine to [2-13C]-L-glutamic acid in the living body of Gryllodes sigillatus. [3-13C]-D-Alanine was not metabolized. The metabolic rate of [1-13C]-D-glucose was found to be altered by prior injection of boric acid.

  15. Liquid-State 13C Polarization of 30% through Photoinduced Nonpersistent Radicals

    DEFF Research Database (Denmark)

    Capozzi, Andrea; Karlsson, Magnus; Petersen, Jan Raagaard

    2018-01-01

    of the nuclear spin polarizationtogether with the constraint of having to polarize the spins nearthe MRI magnet. As recently demonstrated, the employment of UV-inducednonpersistent radicals represents an elegant solution to tacklingthese drawbacks. Nevertheless, since its introduction, the spreadof the technique......-radical technique. Under optimal conditions,it was possible to produce up to 60 mM radical in less than 5 minand reach maximum DNP enhancement with a buildup time constant ofapproximately 25 min at 6.7 T and 1 K, resulting in 30% 13C liquid-state polarization....

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

    International Nuclear Information System (INIS)

    Pahl-Wostl, C.; Seelig, J.

    1986-01-01

    The hormonal regulation of ketogenesis in the liver of living rat has been studied noninvasively with 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 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 13 C signal intensities were enhanced by using doubly labeled [1,3- 13 C]butyrate as a substrate. Different 13 C NMR spectra and hence different metabolites were observed depending on the hormonal state of the animal. The 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 13 C label into the carbons of 3-hydroxybutyrate, it could be estimated that a large fraction of butyrate evaded β-oxidation to acetyl-CoA but was converted directly to acetoacetyl-CoA. 13 C-labeled glucose could be detected in vivo in the liver of diabetic rats

  17. 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

  18. Solid state CP/MAS 13C n.m.r. analysis of particle size and density fractions of soil incubated with uniformly labelled 13C-glucose

    International Nuclear Information System (INIS)

    Baldock, J.A.; Oades, J.M.

    1990-01-01

    A soil incubated for 34 days in the absence (control) and presence (treated) of uniformly labelled 13 C-glucose was dispersed using an ultrasonic probe and fractionated by sedimentation in water and a polytungstate solution of density 2.0 Mg m -3 . Solid state CP/MAS 13 C n.m.r. (cross polarization/magic angle spinning 13 C nuclear magnetic resonance) spectroscopy was used to characterize the chemical structure of the native soil organic carbon and the residual substrate carbon in the fractions of the control and treated soils. To obtain quantitative results it was essential to determine the spin lattice relaxation time in a rotating frame of the individual carbon types in the spectra as the relaxation behaviour of the native organic material in the clay fraction was different from that of the residual substrate carbon. The residual substrate carbon was found to accumulate in predominantly alkyl and O-alkyl structures in both fractions. However, significant amounts of acetal and carboxyl carbon were also observed in the clay fraction. Little if any aromatic or phenolic carbon was synthesized by the soil microorganisms utilizing substrate carbon. Dipolar dephasing CP/MAS 13 C n.m.r. experiments were also performed and allowed the proportion of each type of carbon which was protonated and nonprotonated to be estimated. Essentially all of the O-alkyl and acetal carbon, 25-40% of the aromatic carbon and 66-80% of the alkyl carbon was protonated in the fractions isolated from the treated soil. 24 refs., 4 figs., 2 tabs

  19. Resonant states in 13C and 16,17O at high excitation energy

    Science.gov (United States)

    Rodrigues, M. R. D.; Borello-Lewin, T.; Miyake, H.; Duarte, J. L. M.; Rodrigues, C. L.; Horodynski-Matsushigue, L. B.; Ukita, G. M.; Cappuzzello, F.; Cavallaro, M.; Foti, A.; Agodi, C.; Cunsolo, A.; Carbone, D.; Bondi, M.; De Napoli, M.; Roeder, B. T.; Linares, R.; Lombardo, I.

    2014-12-01

    The 9Be(6Li,d)13C and 12,13C(6Li,d)16,17O reactions were measured at the São Paulo Pelletron-Enge-Spectrograph facility at 25.5 MeV incident energy. The nuclear emulsion detection technique was applied. Several narrow resonances were populated up to approximately 17 MeV of excitation energy. An excellent energy resolution was obtained: 40 keV for 13C and 15-30 keV for 16O. The upper limit for the resonance widths were determined. Recently, d-a angular correlations were measured at θd = 0° with incident energy of 25 MeV using the LNS Tandem-MAGNEX Spectrometer facility.

  20. Resonant states in 13C and 16,17O at high excitation energy

    International Nuclear Information System (INIS)

    Rodrigues, M R D; Borello-Lewin, T; Miyake, H; Duarte, J L M; Rodrigues, C L; Horodynski-Matsushigue, L B; Ukita, G M; Cappuzzello, F; Foti, A; Cavallaro, M; Agodi, C; Cunsolo, A; Carbone, D; Bondi, M; Napoli, M De; Roeder, B T; Linares, R; Lombardo, I

    2014-01-01

    The 9 Be( 6 Li,d) 13 C and 12,13 C( 6 Li,d) 16,17 O reactions were measured at the São Paulo Pelletron-Enge-Spectrograph facility at 25.5 MeV incident energy. The nuclear emulsion detection technique was applied. Several narrow resonances were populated up to approximately 17 MeV of excitation energy. An excellent energy resolution was obtained: 40 keV for 13 C and 15-30 keV for 16 O. The upper limit for the resonance widths were determined. Recently, d-a angular correlations were measured at θ d = 0° with incident energy of 25 MeV using the LNS Tandem-MAGNEX Spectrometer facility

  1. (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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. 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

    . 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...

  3. Existence of halo-structure for the first excited levels of both the 13C-13N and the 17O-17F nuclei

    International Nuclear Information System (INIS)

    Gridnev, K.A.; Novatskij, B.G.

    2003-01-01

    From calculated the Coulomb shifts difference for the carbon and oxygen isotopes analog levels the valent nucleons the orbit radius values R C and the density parameter r 0 are presented. It is shown that the density parameter values are slightly varying for the all analog nuclear pairs. The exception constitutes the first excited states of the 13 C- 13 N and the 17 O- 17 F nuclei, whose valent nucleons populate the 2s-shell (L=0). These states one can to consider as structures with brightly distinguished of the ( 13 C * , 17 O * ) neutron halo and the( 13 N * , 17 F * ) proton halo

  4. Quantitative determination of Quarternary alicyclic carbon atoms in coal and oil using nuclear magnetic resonance /sup 13/C method

    Energy Technology Data Exchange (ETDEWEB)

    Afonina, T.V.; Kushnarev, D.F.; Randin, O.I.; Shishkov, V.F.; Kalabin, G.A.

    1986-09-01

    Possibility is indicated for utilizing nuclear magnetic resonance spectroscopy for quantitative determination of Quarternary aliphatic carbon atoms in heavy hydrocarbon fractions of oil and coal extracts. C/sub n/, CH, CH/sub 2/ and CH/sub 3/ content in coal and oil samples are determined and corresponding resonance lines are referred to individual structural fragments (on the basis of nuclear magnetic resonance /sup 13/C spectra) of known saturated hydrocarbons. Tests were carried out on chloroform extracts of Irsha-Borodinsk coal, Mungunsk coal and paraffin and cycloparaffin of Sivinsk oil (b.p. over 550 C) fractions. Nuclear magnetic resonance spectra were obtained using Burker WP 200 spectrometer (50.13 MHz frequency). Results of the tests are given. 11 references.

  5. Synthesis of selectively 13C-labelled benzoic acid for nuclear magnetic resonance spectroscopic measurement of glycine conjugation activity

    International Nuclear Information System (INIS)

    Akira, Kazuki; Hasegawa, Hiroshi; Baba, Shigeo

    1995-01-01

    The synthesis of [4- 13 C]benzoic acid (BA) labelled in a single protonated carbon, for use as a probe to measure glycine conjugation activity by nuclear magnetic resonance (NMR) spectroscopy, has been reported. The labelled compound was prepared by a seven-step synthetic scheme on a relatively small scale using [2- 13 C] acetone as the source of label in overall yield of 16%. The usefulness of [4- 13 C]BA was demonstrated by the NMR spectroscopic monitoring of urinary excretion of [4- 13 C]hippuric acid in the rat administered with the labelled BA. (Author)

  6. 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.

  7. Study for the charge symmetric systems, 12C+13N and 12C+13C with the orthogonalized coupled-reaction-channel method

    International Nuclear Information System (INIS)

    Imanishi, B.; Denisov, V.; Motobayashi, T.

    1996-10-01

    The charge-symmetric scattering systems, 12 C+ 13 N and 12 C+ 13 C have been investigated by using the orthogonalized coupled-reaction-channel (OCRC) method with the basis functions of the elastic, inelastic and transfer channels defined by the single-particle states, 1p1/2, 2s1/2, 1d5/2 and 1d3/2 of the valence nucleon in 13 N or 13 C. The data of the elastic scattering of 13 N on 12 C measured by Lienard et al. have been explained consistently with the data of the elastic and inelastic scattering of the 12 C+ 13 C system. The CRC effects both on the above systems are very strong, although those on the 12 C+ 13 N system are fairly weaker than the 12 C+ 13 C system. The role of the highly excited single-particle states 1d3/2 is particularly important in the formation of a specific CRC scheme, i.e., the formation of the covalent molecules due to the hybridization caused by the mixing of the different parity single-particle states. The fusion cross sections of the 12 C+ 13 C system at energies below the Coulomb barrier are strongly enhanced as a result of the strong CRC effects as compared with those of the 12 C+ 12 C system, while in 12 C+ 13 N system the enhancement of the sub-barrier fusion has not been observed. The above absorption mechanism for the 12 C+ 13 C system explains the lack of the molecular-resonance phenomena observed in the 12 C+ 12 C system. We check the effects of the dipole (E1) transition of the valence nucleon in 13 N (and also in 13 C) due to the core-core Coulomb interaction in the scattering at sub-barrier energies. The effects are not appreciable. (author)

  8. Solid state 13 C NMR quantitative study of wood tar pitches

    International Nuclear Information System (INIS)

    Prauchner, Marcos Juliano; Pasa, Vanya Marcia Duarte; Menezes, Sonia Maria Cabral de

    1999-01-01

    In this work, solid-state 13 C NMR is used with other techniques to characterize Eucalyptus tar pitches and to follow their polymerization reactions. The pitches are the residues of distillation (about 50% m;m) of the tar generated in Eucalyptus slow pyrolysis for charcoal production in metal industry

  9. 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.

  10. Structural characterization of supramolecular assemblies by {sup 13}C spin dilution and 3D solid-state NMR

    Energy Technology Data Exchange (ETDEWEB)

    Habenstein, Birgit; Loquet, Antoine; Giller, Karin; Becker, Stefan; Lange, Adam, E-mail: adla@nmr.mpibpc.mpg.de [Max Planck Institute for Biophysical Chemistry, Department of NMR-based Structural Biology (Germany)

    2013-01-15

    {sup 13}C spin diluted protein samples can be produced using [1-{sup 13}C] and [2-{sup 13}C]-glucose (Glc) carbon sources in the bacterial growth medium. The {sup 13}C spin dilution results in favorable {sup 13}C spectral resolution and polarization transfer behavior. We recently reported the combined use of [1-{sup 13}C]- and [2-{sup 13}C]-Glc labeling to facilitate the structural analysis of insoluble and non-crystalline biological systems by solid-state NMR (ssNMR), including sequential assignment, detection of long-range contacts and structure determination of macromolecular assemblies. In solution NMR the beneficial properties of sparsely labeled samples using [2-{sup 13}C]-glycerol ({sup 13}C labeled C{alpha} sites on a {sup 12}C diluted background) have recently been exploited to provide a bi-directional assignment method (Takeuchi et al. in J Biomol NMR 49(1):17-26, 2011 ). Inspired by this approach and our own recent results using [2-{sup 13}C]-Glc as carbon sources for the simplification of ssNMR spectra, we present a strategy for a bi-directional sequential assignment of solid-state NMR resonances and additionally the detection of long-range contacts using the combination of {sup 13}C spin dilution and 3D NMR spectroscopy. We illustrate our results with the sequential assignment and the collection of distance restraints on an insoluble and non-crystalline supramolecular assembly, the Salmonella typhimurium type III secretion system needle.

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

    International Nuclear Information System (INIS)

    Chaintreau, Alain; Fieber, Wolfgang; Sommer, Horst; Gilbert, Alexis; Yamada, Keita; Yoshida, Naohiro; Pagelot, Alain; Moskau, Detlef; Moreno, Aitor; Schleucher, Jürgen; Reniero, Fabiano; Holland, Margaret; Guillou, Claude; Silvestre, Virginie; Akoka, Serge; Remaud, Gérald S.

    2013-01-01

    Graphical abstract: -- Highlights: •First ring test on isotopic 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 13 C NMR spectrometry, which is able to measure intra-molecular 13 C composition, is of emerging demand because of the new information provided by the 13 C site-specific content of a given molecule. A systematic evaluation of instrumental behaviour is of importance to envisage isotopic 13 C NMR as a routine tool. This paper describes the first collaborative study of intra-molecular 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 13 C NMR was then assessed on vanillin from three different origins associated with specific δ 13 C 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 13 C 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

  12. Solid state nuclear magnetic resonance with magic-angle spinning and dynamic nuclear polarization below 25 K.

    Science.gov (United States)

    Thurber, Kent R; Potapov, Alexey; Yau, Wai-Ming; Tycko, Robert

    2013-01-01

    We describe an apparatus for solid state nuclear magnetic resonance (NMR) with dynamic nuclear polarization (DNP) and magic-angle spinning (MAS) at 20-25 K and 9.4 Tesla. The MAS NMR probe uses helium to cool the sample space and nitrogen gas for MAS drive and bearings, as described earlier, but also includes a corrugated waveguide for transmission of microwaves from below the probe to the sample. With a 30 mW circularly polarized microwave source at 264 GHz, MAS at 6.8 kHz, and 21 K sample temperature, greater than 25-fold enhancements of cross-polarized (13)C NMR signals are observed in spectra of frozen glycerol/water solutions containing the triradical dopant DOTOPA-TEMPO when microwaves are applied. As demonstrations, we present DNP-enhanced one-dimensional and two-dimensional (13)C MAS NMR spectra of frozen solutions of uniformly (13)C-labeled l-alanine and melittin, a 26-residue helical peptide that we have synthesized with four uniformly (13)C-labeled amino acids. Published by Elsevier Inc.

  13. 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

    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......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...... 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...

  14. Multinuclear solid-state high-resolution and C-13 -{Al-27} double-resonance magic-angle spinning NMR studies on aluminum alkoxides

    NARCIS (Netherlands)

    Abraham, A.; Prins, R.; Bokhoven, J.A. van; Eck, E.R.H. van; Kentgens, A.P.M.

    2006-01-01

    A combination of Al-27 magic-angle spinning (MAS)/multiple quantum (MQ)-MAS, C-13-H-1 CPMAS, and C-13-{Al-27} transfer of population in double-resonance (TRAPDOR) nuclear magnetic resonance (NMR) were used for the structural elucidation of the aluminum alkoxides aluminum ethoxide, aluminum

  15. 13C-nuclear magnetic resonance studies of the biosynthesis of 5-aminolevolinic acid destined for chlorophyll formation in dark-grown Scenedesmus Obliquus

    International Nuclear Information System (INIS)

    Oh-hama, Tamiko; Seto, Harvo; Miyachi, Shigetoh

    1985-01-01

    The 13 C-nuclear magnetic resonance (NMR) spectra of chlorophyll-α-formed in dark-grown Scenedesmus Obliquus (Turp.) Kutzing in the presence of (1- 13 C) glutamate, (2- 13 C) and (1- 13 C) glycine showed that the 13 C of glutamate was specifically incorporated into the eight-carbon atoms in the tetrapyrrole macrocyles derived from C-5 of 5-aminolevolinic acid (ALA), while the C-2 of glycine was only incorporated into the methyl carbon of the methoxycarbonyl group attached to the isolcyclic ring of chlorophyll a formed in the presence of (1- 13 C)-glycine. These labelling patterns provide evidence for the operation of the C 5 -pathway and against the operation of the ALA synthase pathway for chlorophyll formation in darkness. (author)

  16. Solid-state NMR detection of 14N-13C dipolar couplings between amino acid side groups provides constraints on amyloid fibril architecture.

    Science.gov (United States)

    Middleton, David A

    2011-02-01

    Solid-state nuclear magnetic resonance (SSNMR) is a powerful technique for the structural analysis of amyloid fibrils. With suitable isotope labelling patterns, SSNMR can provide constraints on the secondary structure, alignment and registration of β-strands within amyloid fibrils and identify the tertiary and quaternary contacts defining the packing of the β-sheet layers. Detection of (14)N-(13)C dipolar couplings may provide potentially useful additional structural constraints on β-sheet packing within amyloid fibrils but has not until now been exploited for this purpose. Here a frequency-selective, transfer of population in double resonance SSNMR experiment is used to detect a weak (14)N-(13)C dipolar coupling in amyloid-like fibrils of the peptide H(2)N-SNNFGAILSS-COOH, which was uniformly (13)C and (15)N labelled across the four C-terminal amino acids. The (14)N-(13)C interatomic distance between leucine and asparagine side groups is constrained between 2.4 and 3.8 Å, which allows current structural models of the β-spine arrangement within the fibrils to be refined. This procedure could be useful for the general structural analysis of other proteins in condensed phases and environments, such as biological membranes. Copyright © 2011 John Wiley & Sons, Ltd.

  17. In vivo assessment of intracellular redox state in rat liver using hyperpolarized [1-13 C]Alanine.

    Science.gov (United States)

    Park, Jae Mo; Khemtong, Chalermchai; Liu, Shie-Chau; Hurd, Ralph E; Spielman, Daniel M

    2017-05-01

    The intracellular lactate to pyruvate concentration ratio is a commonly used tissue assay biomarker of redox, being proportional to free cytosolic [NADH]/[NAD + ]. In this study, we assessed the use of hyperpolarized [1- 13 C]alanine and the subsequent detection of the intracellular products of [1- 13 C]pyruvate and [1- 13 C]lactate as a useful substrate for assessing redox levels in the liver in vivo. Animal experiments were conducted to measure in vivo metabolism at baseline and after ethanol infusion. A solution of 80-mM hyperpolarized [1- 13 C]alanine was injected intravenously at baseline (n = 8) and 45 min after ethanol infusion (n = 4), immediately followed by the dynamic acquisition of 13 C MRS spectra. In vivo rat liver spectra showed peaks from [1- 13 C] alanine and the products of [1- 13 C]lactate, [1- 13 C]pyruvate, and 13 C-bicarbonate. A significantly increased 13 C-lactate/ 13 C-pyruvate ratio was observed after ethanol infusion (8.46 ± 0.58 at baseline versus 13.58 ± 0.69 after ethanol infusion; P alanine is presented, with the validity of the proposed 13 C-pyruvate/ 13 C-lactate metric tested using an ethanol challenge to alter liver redox state. Magn Reson Med 77:1741-1748, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  18. Contribution of exogenous substrates to acetyl coenzyme A: Measurement by 13C NMR under non-steady-state conditions

    International Nuclear Information System (INIS)

    Malloy, C.R.; Jeffrey, F.M.H.; Thompson, J.R.; Sherry, A.D.

    1990-01-01

    A method is presented for the rapid determination of substrate selection in a manner that is not restricted to conditions of metabolic and isotopic steady state. Competition between several substrates can be assessed directly and continuously in a single experiment, allowing the effect of interventions to be studied. It is shown that a single proton-decoupled 13 C NMR spectrum of glutamate provides a direct measure of the contribution of exogenous 13 C-labeled substrates to acetyl-CoA without measurement of oxygen consumption and that steady-state conditions need not apply. Two sets of experiments were performed: one in which a metabolic steady state but a non-steady-state 13 C distribution was achieved and another in which both metabolism and labeling were not at steady state. In the first group, isolated rat hearts were supplied with [1,2- 13 C]acetate, [3- 13 C]lactate, and unlabeled glucose. 13 C NMR spectra of extracts from hearts perfused under identical conditions for 5 or 30 min were compared. In spite of significant differences in the spectra, the measured contributions of acetate, lactate, and unlabeled sources to acetyl-CoA were the same. In the second set of experiments, the same group of labeled substrates was used in a regional ischemia model in isolated rabbit hearts to show regional differences in substrate utilization under both metabolic and isotopic non steady state. The time resolution of these measurements may not be limited by technical contraints but by the rate of carbon flux in the citric acid cycle. Although this technique is demonstrated for the heart, it is applicable to all tissues

  19. 13C-NMR of diterpenes with pimarane skeleton

    International Nuclear Information System (INIS)

    Garcez, W.S.; Pereira, A.L.; Silva Queiroz, P.P. da; Silva, R.S. da; Valente, L.M.M.; Peixoto, E.M.; Cunha Pinto, A. da

    1981-01-01

    The effect of substituent groups on the chemical shift of carbons using nuclear magnetic resonance spectra of carbon 13 ( 13 C-NMR) is discussed. Diterpenes having pimarane skeleton, isolated from plants of Velloziaceae family are analysed. (ARHC) [pt

  20. Selective and extensive 13C labeling of a membrane protein for solid-state NMR investigations

    International Nuclear Information System (INIS)

    Hong, M.; Jakes, K.

    1999-01-01

    The selective and extensive 13C labeling of mostly hydrophobic amino acid residues in a 25 kDa membrane protein, the colicin Ia channel domain, is reported. The novel 13C labeling approach takes advantage of the amino acid biosynthetic pathways in bacteria and suppresses the synthesis of the amino acid products of the citric acid cycle. The selectivity and extensiveness of labeling significantly simplify the solid-state NMR spectra, reduce line broadening, and should permit the simultaneous measurement of multiple structural constraints. We show the assignment of most 13C resonances to specific amino acid types based on the characteristic chemical shifts, the 13C labeling pattern, and the amino acid composition of the protein. The assignment is partly confirmed by a 2D homonuclear double-quantum-filter experiment under magic-angle spinning. The high sensitivity and spectral resolution attained with this 13C-labeling protocol, which is termed TEASE for ten-amino acid selective and extensive labeling, are demonstrated

  1. Synthesis and characterization of "1"3C_3-tristearin

    International Nuclear Information System (INIS)

    Wu Hangyu; Lin Lin; Li Lei; Chen Dazhou

    2011-01-01

    A highly efficient synthesis of "1"3C_3 labeled triglycerides of stearic acids from "1"3C_3-glycerol and stearic acids, by immobilized lipase-catalyzed in solvent-free medium was described. The structure of the product were characterized by fourier transform infrared spectrum (FT-IR), nuclear magnetic resonance (NMR), mass spectra (MS). The results showed that triglycerides of stearic acids contained three "1"3C atoms. The isotope abundance of "1"3C_3-tristearin was more than 99% and the yield was 80% of "1"3C_3-tristearin through calculation. Chemical purity (> 98%) was obtained by differential scanning calorimetry (DSC). (authors)

  2. Barnwell Nuclear Fuel Plant. IE inspection report No. 75-13

    International Nuclear Information System (INIS)

    1975-01-01

    Copies of the following documents are presented: letter to N. C. Moseley from Allied-General Nuclear Services dated October 16, 1975; letter to Allied-General Nuclear Services from N. C.Moseley dated October 7, 1975; and Region II Inspection Report No. 50-332/75-13

  3. Dynamically Decoupled 13C Spins in Hyperpolarized Nanodiamond

    Science.gov (United States)

    Rej, Ewa; Gaebel, Torsten; Boele, Thomas; Waddington, David; Reilly, David

    The spin-spin relaxation time, T2, which determines how long a quantum state remains coherent, is an important factor for many applications ranging from MRI to quantum computing. A common technique used in quantum information technology to extend the T2, involves averaging out certain noise spectra via dynamical decoupling sequences. Depending on the nature of the noise in the system, specific sequences, such as CPMG, UDD or KDD, can be tailored to optimize T2. Here we combine hyperpolarization techniques and dynamical decoupling sequences to extend the T2 of 13C nuclear spins in nanodiamond by three orders of magnitude.

  4. Experiments and strategies for the assignment of fully13 C/15N-labelled polypeptides by solid state NMR

    International Nuclear Information System (INIS)

    Straus, Suzana K.; Bremi, Tobias; Ernst, Richard R.

    1998-01-01

    High-resolution heteronuclear NMR correlation experiments and strategies are proposed for the assignment of fully 13 C/ 15 N-labelled polypeptides in the solid state. By the combination of intra-residue and inter-residue 13 C- 15 N correlation experiments with 13 C- 13 C spin-diffusion studies, it becomes feasible to partially assign backbone and side-chain resonances in solid proteins. The performance of sequences using 15 N instead of 13 C detection is evaluated regarding sensitivity and resolution for a labelled dipeptide (L-Val-L-Phe). The techniques are used for a partial assignment of the 15 N and 13 C resonances in human ubiquitin

  5. Assessing the extent of decomposition of natural organic materials using solid-state 13C NMR spectroscopy

    International Nuclear Information System (INIS)

    Baddock, J.A.; Oades, J.M.; Nelson, P.N.; Skene, T.M.; Golchin, A.; Clarke, P.

    1997-01-01

    Solid-state 13 C nuclear magnetic resonance (NMR) spectroscopy has become an important tool for examining the chemical structure of natural organic materials and the chemical changes associated with decomposition. In this paper, solid-state 13 C NMR data pertaining to changes in the chemical composition of a diverse range of natural organic materials, including wood, peat, composts, forest litter layers, and organic materials in surface layers of mineral soils, were reviewed with the objective of deriving an index of the extent of decomposition of such organic materials based on changes in chemical composition. Chemical changes associated with the decomposition of wood varied considerably and were dependent on a strong interaction between the species of wood examined and the species composition of the microbial decomposer community, making the derivation of a single general index applicable to wood decomposition unlikely. For the remaining forms of natural organic residues, decomposition was almost always associated with an increased content of alkyl C and a decreased content of O-alkyl C. The concomitant increase and decrease in alkyl and O-alkyl C contents, respectively, suggested that the ratio of alkyl to O-alkyl carbon (A/O-A ratio) may provide a sensitive index of the extent of decomposition. Contrary to the traditional view that humic substances with an aromatic core accumulate as decomposition proceeds, changes in the aromatic region were variable and suggested a relationship with the activity of lignin-degrading fungi. The A/O-A ratio did appear to provide a sensitive index of extent of decomposition provided that its use was restricted to situations where the organic materials were derived from a common starting material. In addition, the potential for adsorption of highly decomposable materials on mineral soil surfaces and the impacts which such an adsorption may have on bioavailability required consideration when the A/O-A ratio was used to assess the

  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 (T 1 ) 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 T 1 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 T 1 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 T 1 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 T 1 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 T 1 of sodium hydrogencarbonate solutions. Finally, this work also investigates the influence of pH on the spin-lattice relaxation of cesium

  7. 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.

  8. Calibration of an analyzing magnet using the 12C(d, p0)13C nuclear reaction with a thick carbon target

    Science.gov (United States)

    Andrade, E.; Canto, C. E.; Rocha, M. F.

    2017-09-01

    The absolute energy of an ion beam produced by an accelerator is usually determined by an electrostatic or magnetic analyzer, which in turn must be calibrated. Various methods for accelerator energy calibration are extensively reported in the literature, like nuclear reaction resonances, neutron threshold, and time of flight, among others. This work reports on a simple method to calibrate the magnet associated to a vertical 5.5 MV Van de Graaff accelerator. The method is based on bombarding with deuteron beams a thick carbon target and measuring with a surface barrier detector the particle energy spectra produced. The analyzer magnetic field is measured for each spectrum and the beam energy is deduced by the best fit of the simulation of the spectrum with the SIMNRA code that includes 12C(d,p0)13C nuclear cross sections.

  9. Identification of aquatically available carbon from algae through solution-state NMR of whole (13)C-labelled cells.

    Science.gov (United States)

    Akhter, Mohammad; Dutta Majumdar, Rudraksha; Fortier-McGill, Blythe; Soong, Ronald; Liaghati-Mobarhan, Yalda; Simpson, Myrna; Arhonditsis, George; Schmidt, Sebastian; Heumann, Hermann; Simpson, André J

    2016-06-01

    Green algae and cyanobacteria are primary producers with profound impact on food web functioning. Both represent key carbon sources and sinks in the aquatic environment, helping modulate the dissolved organic matter balance and representing a potential biofuel source. Underlying the impact of algae and cyanobacteria on an ecosystem level is their molecular composition. Herein, intact (13)C-labelled whole cell suspensions of Chlamydomonas reinhardtii, Chlorella vulgaris and Synechocystis were studied using a variety of 1D and 2D (1)H/(13)C solution-state nuclear magnetic resonance (NMR) spectroscopic experiments. Solution-state NMR spectroscopy of whole cell suspensions is particularly relevant as it identifies species that are mobile (dissolved or dynamic gels), 'aquatically available' and directly contribute to the aquatic carbon pool upon lysis, death or become a readily available food source on consumption. In this study, a wide range of metabolites and structural components were identified within the whole cell suspensions. In addition, significant differences in the lipid/triacylglyceride (TAG) content of green algae and cyanobacteria were confirmed. Mobile species in algae are quite different from those in abundance in 'classic' dissolved organic matter (DOM) indicating that if algae are major contributors to DOM, considerable selective preservation of minor components (e.g. sterols) or biotransformation would have to occur. Identifying the metabolites and dissolved components within algal cells by NMR permits future studies of carbon transfer between species and through the food chain, whilst providing a foundation to better understand the role of algae in the formation of DOM and the sequestration/transformation of carbon in aquatic environments.

  10. Whole-core analysis by 13C NMR

    International Nuclear Information System (INIS)

    Vinegar, H.J.; Tutunjian, P.N.; Edelstein, W.A.; Roemer, P.B.

    1991-01-01

    This paper reports on a whole-core nuclear magnetic resonance (NMR) system that was used to obtain natural abundance 13 C spectra. The system enables rapid, nondestructive measurements of bulk volume of movable oil, aliphatic/aromatic ratio, oil viscosity, and organic vs. carbonate carbon. 13 C NMR can be used in cores where the 1 H NMR spectrum is too broad to resolve oil and water resonances separately. A 5 1/4-in. 13 C/ 1 H NMR coil was installed on a General Electric (GE) CSI-2T NMR imager/spectrometer. With a 4-in.-OD whole core, good 13 C signal/noise ratio (SNR) is obtained within minutes, while 1 H spectra are obtained in seconds. NMR measurements have been made of the 13 C and 1 H density of crude oils with a wide range of API gravities. For light- and medium-gravity oils, the 13 C and 1 H signal per unit volume is constant within about 3.5%. For heavy crudes, the 13 C and 1 H density measured by NMR is reduced by the shortening of spin-spin relaxation time. 13 C and 1 H NMR spin-lattice relaxation times were measured on a suite of Cannon viscosity standards, crude oils (4 to 60 degrees API), and alkanes (C 5 through C 16 ) with viscosities at 77 degrees F ranging from 0.5 cp to 2.5 x 10 7 cp. The 13 C and 1 H relaxation times show a similar correlation with viscosity from which oil viscosity can be estimated accurately for viscosities up to 100 cp. The 13 C surface relaxation rate for oils on water-wet rocks is very low. Nonproton decoupled 13 C NMR is shown to be insensitive to kerogen; thus, 13 C NMR measures only the movable hydrocarbon content of the cores. In carbonates, the 13 C spectrum also contains a carbonate powder pattern useful in quantifying inorganic carbon and distinguishing organic from carbonate carbon

  11. Changes in Lignin and Polysaccharide Components in 13 Cultivars of Rice Straw following Dilute Acid Pretreatment as Studied by Solution-State 2D 1H-13C NMR

    Science.gov (United States)

    Teramura, Hiroshi; Sasaki, Kengo; Oshima, Tomoko; Aikawa, Shimpei; Matsuda, Fumio; Okamoto, Mami; Shirai, Tomokazu; Kawaguchi, Hideo; Ogino, Chiaki; Yamasaki, Masanori; Kikuchi, Jun; Kondo, Akihiko

    2015-01-01

    A renewable raw material, rice straw is pretreated for biorefinery usage. Solution-state two-dimensional (2D) 1H-13 C hetero-nuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscopy, was used to analyze 13 cultivars of rice straw before and after dilute acid pretreatment, to characterize general changes in the lignin and polysaccharide components. Intensities of most (15 of 16) peaks related to lignin aromatic regions, such as p-coumarate, guaiacyl, syringyl, p-hydroxyphenyl, and cinnamyl alcohol, and methoxyl, increased or remained unchanged after pretreatment. In contrast, intensities of most (11 of 13) peaks related to lignin aliphatic linkages or ferulate decreased. Decreased heterogeneity in the intensities of three peaks related to cellulose components in acid-insoluble residues resulted in similar glucose yield (0.45–0.59 g/g-dry biomass). Starch-derived components showed positive correlations (r = 0.71 to 0.96) with glucose, 5-hydroxymethylfurfural (5-HMF), and formate concentrations in the liquid hydrolysates, and negative correlations (r = –0.95 to –0.97) with xylose concentration and acid-insoluble residue yield. These results showed the fate of lignin and polysaccharide components by pretreatment, suggesting that lignin aromatic regions and cellulose components were retained in the acid insoluble residues and starch-derived components were transformed into glucose, 5-HMF, and formate in the liquid hydrolysate. PMID:26083431

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

    DEFF Research Database (Denmark)

    Borgwardt, Henrik Gutte; Hansen, Adam Espe; 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......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...... (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...

  13. Nuclear power in the United States

    International Nuclear Information System (INIS)

    Johnston, J.B.

    1985-01-01

    All over the world except in the United States, nuclear energy is a low cost, secure, environmentally acceptable form of energy. In the United States, civilian nuclear power is dead. 112 nuclear power plants have been abandoned or cancelled in the last decade, and there has been no new order for nuclear plants since 1978. It will be fortunate to have 125 operating nuclear plants in the United States in the year 2000. There are almost 90 completed nuclear power plants and about 45 under construction in the United States, but several of those under construction will eventually be abandoned. About 20 % of the electricity in the United States will be generated by nuclear plants in 2000 as compared with 13 % supplied in the last year. Under the present regulatory and institutional arrangement, American electric utilities would not consider to order a new nuclear power plant. Post-TMI nuclear plants became very expensive, and there is also ideological opposition to nuclear power. Coal-firing plants are also in the similar situation. The uncertainty about electric power demand, the cost of money, the inflation of construction cost and regulation caused the situation. (Kako, I.)

  14. State-of-art report on digital I and C system reliability issues for nuclear power plants

    International Nuclear Information System (INIS)

    Hwang, In Koo; Lee, Dong Gyoung; Cha, Kyung Ho; Kwon, Kee Choon; Wood, Richard T.

    2000-01-01

    As the instrumentation and control (Iand C) equipment suppliers tend to provide digital components rather than conventional analog type components for instrument and control systems of nuclear power plants(NPPs), it is unavoidable to adopt digital equipment for safety I and C systems as well as non-safety systems. However, the full introduction of digital equipment to I and C systems of nuclear power plants raises several concerns which have not been considered for conventional analog I and C systems. The two major examples of the issues of digital systems are electromagnetic compatibility (EMC) and software reliability. KAERI invited a technical expert, Dr. Richard T. Wood, from Oak Ridge National Laboratory (ORNL) in Unites States and held seminars to recognize the state-of-art of the above issues and to share the information on techniques dealing with the problems. Dr. Wood has been working on the development of EMC guidelines and technical basis in using digital equipment for safety systems in nuclear power plants on the sponsorship of US Nuclear Regulatory Commission (NRC). Being based on his statements and discussions during his visit, this report describes technical considerations and issues on digital safety I and C system application in NPPs, EMC methods, environmental effects vulnerable to digital components, reliability assurance methods, etc. (author)

  15. 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

  16. 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.

  17. Cellular applications of 31P and 13C nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Shulman, R.G.; Brown, T.R.; Ugurbil, K.; Ogawa, S.; Cohen, S.M.; den Hollander, J.A.

    1979-01-01

    High-resolution nuclear magnetic resonance (NMR) studies of cells and purified mitochondria are discussed to show the kind of information that can be obtained in vivo. In suspensions of Escherichia coli both phosphorus-31 and carbon-13 NMR studies of glycolysis of bioenergetics are presented. In rat liver cells the pathways of gluconeogenesis from carbon-13-labeled glycerol are followed by carbon-13 NMR. In the intact liver cells cytosolic and mitochondrial pH's were separately measured by phosphorus-31 NMR. In purified mitochondria the internal and external concentrations of inorganic phosphate, adenosine diphosphate, and adenosine triphosphate were determined by phosphorus-31 while the pH difference across the membrane was measured simultaneously

  18. Comparison of Australasian tertiary coals based on resolution- enhanced solid-state /sup 13/C NMR spectra

    Energy Technology Data Exchange (ETDEWEB)

    Newman, R H; Davenport, S J

    1986-04-01

    /sup 13/C solid-state nuclear magnetic resonance spectroscopy was used to characterize 32 low-rank coals from New Zealand and Australia. A combination of high magnetic field (4.7 T) and resolution enhancement was used to extract spectral details beyond those seen in published spectra of coals of similar rank. Signal heights were used to characterize organic functional distributions. The spectra showed close similarities between Australian brown coals and low-rank New Zealand subbituminous coals, particularly those mined in the North Island. The spectra of New Zealand lignites all showed stronger signals from cellulose, methoxyl groups and phenols. Almost all of the New Zealand coals showed a relatively strong signal from polymethylene chains, compared with the Australian brown coals. This led to a prediction of higher alkene yields from pyrolysis of the New Zealand coals. Variations in phenolic substitution patterns were attributed to variations in the relative proportions of tannins and lignins in the depositional environments.

  19. Detailed 1H and 13C NMR spectral data assignment for two dihydrobenzofuran neolignans

    International Nuclear Information System (INIS)

    Medeiros, Talita C.T.; Dias, Herbert J.; Crotti, Antônio E.M.

    2016-01-01

    In this work we present a complete proton ( 1 H) and carbon 13 ( 13 C) nuclear magnetic resonance (NMR) spectral analysis of two synthetic dihydrofuran neolignans (±)-trans-dehydrodicoumarate dimethyl ester and (±)-trans-dehydrodiferulate dimethyl ester. Unequivocal assignments were achieved by 1 H NMR, proton decoupled 13 C ( 13 C{ 1 H}) NMR spectra, gradient-selected correlation spectroscopy (gCOSY), J-resolved, gradient-selected heteronuclear multiple quantum coherence (gHMQC), gradient-selected heteronuclear multiple bond coherence (gHMBC) and nuclear Overhauser effect spectroscopy (NOESY) experiments. All hydrogen coupling constants were measured, clarifying all the hydrogen signals multiplicities. Computational methods were also used to simulate the 1 H and 13 C chemical shifts and showed good agreement with the trans configuration of the substituents at C 7 and C 8 . (author)

  20. (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.

  1. Sparse "1"3C labelling for solid-state NMR studies of P. pastoris expressed eukaryotic seven-transmembrane proteins

    International Nuclear Information System (INIS)

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

    2016-01-01

    We demonstrate a novel sparse "1"3C labelling approach for methylotrophic yeast P. pastoris expression system, towards solid-state NMR studies of eukaryotic membrane proteins. The labelling scheme was achieved by co-utilizing natural abundance methanol and specifically "1"3C labelled glycerol as carbon sources in the expression medium. This strategy improves the spectral resolution by 1.5 fold, displays site-specific labelling patterns, and has advantages for collecting long-range distance restraints for structure determination of large eukaryotic membrane proteins by solid-state NMR.

  2. The influence of feedstock and production temperature on biochar carbon chemistry: A solid-state 13C NMR study

    International Nuclear Information System (INIS)

    McBeath, Anna V.; Smernik, Ronald J.; Krull, Evelyn S.; Lehmann, Johannes

    2014-01-01

    Solid-state 13 C nuclear magnetic resonance (NMR) spectroscopy was used to evaluate the carbon chemistry of twenty-six biochars produced from eleven different feedstocks at production temperatures ranging from 350 °C to 600 °C. Carbon-13 NMR spectra were acquired using both cross-polarisation (CP) and direct polarisation (DP) techniques. Overall, the corresponding CP and DP spectra were similar, although aromaticity was slightly higher and observability much higher when DP was used. The relative size and purity of the aromatic ring structures (i.e. aromatic condensation) were also gauged using the ring current technique. Both aromaticity and aromatic condensation increased with increasing production temperature, regardless of the feedstock source. However, there were clear differences in these two measures for biochars produced at the same temperature but from different feedstocks. Based on a relationship previously established in a long-term incubation study between aromatic condensation and the mean residence time (MRT) of biochar, the MRT of the biochars was estimated to range from 1400 years. This study demonstrates how the combination of feedstock composition and production temperature influences the composition of aromatic domains in biochars, which in turn is likely to be related to their recalcitrance and ultimately their carbon sequestration value. -- Highlights: • Sensitive NMR techniques were used to gauge differences in biochar carbon chemistry. • Varying pyrolysis conditions influences biochars recalcitrant properties. • The MRT of contrasting biochars varies considerably from 1400 years

  3. 13C spin relaxation measurements in RNA: Sensitivity and resolution improvement using spin-state selective correlation experiments

    International Nuclear Information System (INIS)

    Boisbouvier, Jerome; Brutscher, Bernhard; Simorre, Jean-Pierre; Marion, Dominique

    1999-01-01

    A set of new NMR pulse sequences has been designed for the measurement of 13 C relaxation rate constants in RNA and DNA bases: the spin-lattice relaxation rate constant R(C z ), the spin-spin relaxation rate constant R(C + ), and the CSA-dipolar cross-correlated relaxation rate constant Γ C,CH xy . The use of spin-state selective correlation techniques provides increased sensitivity and spectral resolution. Sensitivity optimised C-C filters are included in the pulse schemes for the suppression of signals originating from undesired carbon isotopomers. The experiments are applied to a 15% 13 C-labelled 33-mer RNA-theophylline complex. The measured R(C + )/Γ C,CH xy ratios indicate that 13 C CSA tensors do not vary significantly for the same type of carbon (C 2 , C 6 , C 8 ), but that they differ from one type to another. In addition, conformational exchange effects in the RNA bases are detected as a change in the relaxation decay of the narrow 13 C doublet component when varying the spacing of a CPMG pulse train. This new approach allows the detection of small exchange effects with a higher precision compared to conventional techniques

  4. Metabolic regulation in Streptomyces parvulus during actinomycin D synthesis, studied with 13C- and 15N-labeled precursors by 13C and 15N nuclear magnetic resonance spectroscopy and by gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    Inbar, L.; Lapidot, A.

    1988-01-01

    Recent studies have suggested that the onset of synthesis of actinomycin D in Streptomyces is due to a release from L-glutamate catabolic repression. In the present investigation we showed that S. parvulus has the capacity to maintain high levels of intracellular glutamate during the synthesis of actinomycin D. The results seem contradictory, since actinomycin D synthesis cannot start before a release from L-glutamate catabolic repression, but a relatively high intracellular pool of glutamate is needed for the synthesis of actinomycin D. Utilizing different labeled precursors, D-[U- 13 C]fructose and 13 C- and 15 N-labeled L-glutamate, and nuclear magnetic resonance techniques, we showed that carbon atoms of an intracellular glutamate pool of S. parvulus were not derived biosynthetically from the culture medium glutamte source but rather from D-fructose catabolism. A new intracellular pyrimidine derivative whose nitrogen and carbon skeletons were derived from exogenous L-glutamate was obtained as the main glutamate metabolite. Another new pyrimidine derivative that had a significantly reduced intracellular mobility and that was derived from D-fructose catabolism was identified in the cell extracts of S. parvulus during actinomycin D synthesis. These pyrimidine derivatives may serve as a nitrogen store for actinomycin D synthesis. In the present study, the N-trimethyl group of a choline derivative was observed by 13 C nuclear magnetic resonance spectroscopy in growing S. parvulus cells. The choline group, as well as the N-methyl groups of sarcosine, N-methyl-valine, and the methyl groups of an actinomycin D chromophore, arose from D-fructose catabolism. The 13 C enrichments found in the peptide moieties of actinomycin D were in accordance with a mechanism of actinomycin D synthesis from L-glutamate and D-fructose

  5. Identifying inter-residue resonances in crowded 2D {sup 13}C-{sup 13}C chemical shift correlation spectra of membrane proteins by solid-state MAS NMR difference spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Miao Yimin; Cross, Timothy A. [Florida State University, Department of Chemistry and Biochemistry (United States); Fu Riqiang, E-mail: rfu@magnet.fsu.edu [National High Magnet Field Lab (United States)

    2013-07-15

    The feasibility of using difference spectroscopy, i.e. subtraction of two correlation spectra at different mixing times, for substantially enhanced resolution in crowded two-dimensional {sup 13}C-{sup 13}C chemical shift correlation spectra is presented. With the analyses of {sup 13}C-{sup 13}C spin diffusion in simple spin systems, difference spectroscopy is proposed to partially separate the spin diffusion resonances of relatively short intra-residue distances from the longer inter-residue distances, leading to a better identification of the inter-residue resonances. Here solid-state magic-angle-spinning NMR spectra of the full length M2 protein embedded in synthetic lipid bilayers have been used to illustrate the resolution enhancement in the difference spectra. The integral membrane M2 protein of Influenza A virus assembles as a tetrameric bundle to form a proton-conducting channel that is activated by low pH and is essential for the viral lifecycle. Based on known amino acid resonance assignments from amino acid specific labeled samples of truncated M2 sequences or from time-consuming 3D experiments of uniformly labeled samples, some inter-residue resonances of the full length M2 protein can be identified in the difference spectra of uniformly {sup 13}C labeled protein that are consistent with the high resolution structure of the M2 (22-62) protein (Sharma et al., Science 330(6003):509-512, 2010)

  6. 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. © 2013 Wiley Periodicals, Inc.

  7. /sup 13/C(p vector,d)/sup 12/C and /sup 208/Pb(p vector,d)/sup 207/Pb reactions at 123 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Kraushaar, J J; Shepard, J R [Colorado Univ., Boulder (USA). Nuclear Physics Lab.; Miller, D W; Jacobs, W W; Jones, W P; Devins, D W [Indiana Univ., Bloomington (USA). Dept. of Physics

    1983-02-01

    Cross-section and analyzing power angular distributions have been measured for /sup 13/C(p vector,d) and /sup 208/Pb(p vector, d) at 123 MeV to the strong low-lying residual states in both final nuclei. The data have been compared with the results of both zero- and exact-finite-range distorted wave calculations and some serious discrepancies were noted for the analyzing powers. For the case of the /sup 13/C calculations, marked improvement in the description of the data was achieved with the use of a damping factor in the nuclear interior.

  8. Carbon-13 isotope effects on 199Hg nuclear shielding

    International Nuclear Information System (INIS)

    Sebald, Angelika; Wrackmeyer, Bernd

    1985-01-01

    Secondary 13 C/ 12 C isotope effects on 199 Hg nuclear shielding (Δdeltasup(i)( 199 Hg)) are of interest because of the unusual shift to high frequency which has been observed for a few alkyl mercury compounds. Continuing interest in the NMR parameters of mercury compounds prompted a search for the values Δdeltasup(i)( 199 Hg) in a greater variety of organomercurials. This should help to find out about the range of Δdeltasup(i)( 199 Hg) and to obtain a firmer basis for the discussion of the high-frequency shifts. The data and experimental conditions are given for chemical shifts delta 199 Hg, coupling constants sup(n)J( 199 Hg 13 C) and 13 C/ 12 C isotope shifts Δdeltasup(i)( 199 Hg) of fourteen 199 Hg organomercury compounds. The results are discussed. (author)

  9. Carbonaceous species (coke) characterization in zeolites by solid state {sup 13} C NMR; Caracterizacao de especies carbonaceas (coque) em zeolitos por RMN de {sup 13} C estado solido (CP/MAS)

    Energy Technology Data Exchange (ETDEWEB)

    Mota, Claudio J.A.; Menezes, Sonia C [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    1992-12-31

    This work applies solid state {sup 13} C NMR for characterization of carbonaceous species (coke) deposited on zeolites after contact with n-hexane at 370 deg C. The results have shown two types of carbon: saturated (sp{sup 3}) and unsaturated (sp{sup 2}) 4 refs., 4 tabs.

  10. 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....... Measurement results with a tuning and matching circuit prototype are presented including obtained spectra (13C and 1H) and estimation of the signal-to-noise ratio....

  11. Synthesis of ring-13C-labelled and ring-demethylated retinals

    International Nuclear Information System (INIS)

    Courtin, J.M.L.

    1988-01-01

    Efficient synthetic schemes are described for the preparation of the required mono- and di- 13 C labelled retinals based on simple 13 C labelled starting materials. Results from solid-state 13 C-NMR spectroscopic studies of the various ring- 13 C labelled bacteriorhodopsins and rhodopsins are discussed. 404 refs.; 74 figs.; 16 tabs

  12. Structural characterization of heat treated pitch by solid state /sup 13/C nuclear magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sfihi, H.; Tougne, P.; Legrand, A.P.; Couderc, P.; Saint-Romain, J.L.

    1988-12-01

    The objective of this paper is to determine structural parameters (aromaticity factor, fractions of protonated and non-protonated aromatic carbons) of some pitches, and to follow their evolution as a function of the heat treatment duration. For such a determination, /sup 13/C-/sup 1/H cross polarization combined with magic angle spinning and dipolar dephasing (CP/MAS/DD) NMR was used. 15 refs., 4 figs., 1 tab.

  13. Application of 13C-labeling and 13C-13C COSY NMR experiments in the structure determination of a microbial natural product.

    Science.gov (United States)

    Kwon, Yun; Park, Sunghyouk; Shin, Jongheon; Oh, Dong-Chan

    2014-08-01

    The elucidation of the structures of complex natural products bearing many quaternary carbons remains challenging, even in this advanced spectroscopic era. (13)C-(13)C COSY NMR spectroscopy shows direct couplings between (13)C and (13)C, which comprise the backbone of a natural product. Thus, this type of experiment is particularly useful for natural products bearing consecutive quaternary carbons. However, the low sensitivity of (13)C-based NMR experiments, due to the low natural abundance of the (13)C nucleus, is problematic when applying these techniques. Our efforts in the (13)C labeling of a microbial natural product, cyclopiazonic acid (1), by feeding (13)C-labeled glucose to the fungal culture, enabled us to acquire (13)C-(13)C COSY NMR spectra on a milligram scale that clearly show the carbon backbone of the compound. This is the first application of (13)C-(13)C COSY NMR experiments for a natural product. The results suggest that (13)C-(13)C COSY NMR spectroscopy can be routinely used for the structure determination of microbial natural products by (13)C-enrichment of a compound with (13)C-glucose.

  14. Synthesis of [5,6-13C2, 1-14C]olivetolic acid, methyl [1'-13C]olivetolate and [5,6-13C2, 1-14C]cannabigerolic acid

    International Nuclear Information System (INIS)

    Porwoll, J.P.; Leete, E.

    1985-01-01

    Potential advanced intermediates in the biosynthesis of delta 9 -tetrahydrocannabinol, the major psychoactive principle of marijuana, have been synthesized labeled with two contiguous 13 C atoms and 14 C. Methyl [5,6- 13 C 2 , 1- 14 C]olivetolate was prepared from lithium [ 13 C 2 ]acetylide and dimethyl [2- 14 C]malonate. Reaction with geranyl bromide afforded methyl [5,6- 13 C 2 , 1- 14 C]cannabigerolate, and hydrolysis of these methyl esters with lithium propyl mercaptide yielded the corresponding labeled acids. The 13 C- 13 C couplings observable in the 13 C NMR spectra of these 13 C-enriched compounds and their synthetic precursors are recorded. Methyl [1'- 14 C]olivetolate was prepared from 13 CO 2 to confirm assignments of the 13 C chemical shifts in the pentyl side chain of these compounds. (author)

  15. Validated ¹H and 13C Nuclear Magnetic Resonance Methods for the Quantitative Determination of Glycerol in Drug Injections.

    Science.gov (United States)

    Lu, Jiaxi; Wang, Pengli; Wang, Qiuying; Wang, Yanan; Jiang, Miaomiao

    2018-05-15

    In the current study, we employed high-resolution proton and carbon nuclear magnetic resonance spectroscopy (¹H and 13 C NMR) for quantitative analysis of glycerol in drug injections without any complex pre-treatment or derivatization on samples. The established methods were validated with good specificity, linearity, accuracy, precision, stability, and repeatability. Our results revealed that the contents of glycerol were convenient to calculate directly via the integration ratios of peak areas with an internal standard in ¹H NMR spectra, while the integration of peak heights were proper for 13 C NMR in combination with an external calibration of glycerol. The developed methods were both successfully applied in drug injections. Quantitative NMR methods showed an extensive prospect for glycerol determination in various liquid samples.

  16. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. 13C NMR and EPR spectroscopic evaluation of oil shale mined soil recuperation

    International Nuclear Information System (INIS)

    Santos, J.V. dos; Mangrich, A.S.; Pereira, B.F.; Pillon, C.N.; Bonagamba, T.J.

    2013-01-01

    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 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 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 2+ correlated positively with uronic acid-type hydrophilic organic structures, determined from the 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)

  18. Potential energy curves and spectroscopic properties of X2Σ+ and A2Π states of 13C14N

    International Nuclear Information System (INIS)

    Liao Jian-Wen; Yang Chuan-Lu

    2014-01-01

    The potential energy curves (PECs) of X 2 Σ + and A 2 Π states of the CN molecule have been calculated with the multi-reference configuration interaction method and the aug-cc-pwCV5Z basis set. Based on the PECs, all of the vibrational and rotational levels of the 13 C 14 N molecule are obtained by solving the Schrödinger equation of the molecular nuclear motion. The spectroscopic parameters are determined by fitting the Dunham coefficients with the levels. Both the levels and the spectroscopic parameters are in good qualitative agreement with the experimental data available. The analytical potential energy functions are also deduced from the calculated PECs. The present results can provide a helpful reference for future spectroscopy experiments or dynamical calculations of the molecule. (atomic and molecular physics)

  19. Sub-minute kinetics of human red cell fumarase: 1 H spin-echo NMR spectroscopy and 13 C rapid-dissolution dynamic nuclear polarization.

    Science.gov (United States)

    Shishmarev, Dmitry; Wright, Alan J; Rodrigues, Tiago B; Pileio, Giuseppe; Stevanato, Gabriele; Brindle, Kevin M; Kuchel, Philip W

    2018-03-01

    Fumarate is an important probe of metabolism in hyperpolarized magnetic resonance imaging and spectroscopy. It is used to detect the release of fumarase in cancer tissues, which is associated with necrosis and drug treatment. Nevertheless, there are limited reports describing the detailed kinetic studies of this enzyme in various cells and tissues. Thus, we aimed to evaluate the sub-minute kinetics of human red blood cell fumarase using nuclear magnetic resonance (NMR) spectroscopy, and to provide a quantitative description of the enzyme that is relevant to the use of fumarate as a probe of cell rupture. The fumarase reaction was studied using time courses of 1 H spin-echo and 13 C-NMR spectra. 1 H-NMR experiments showed that the fumarase reaction in hemolysates is sufficiently rapid to make its kinetics amenable to study in a period of approximately 3 min, a timescale characteristic of hyperpolarized 13 C-NMR spectroscopy. The rapid-dissolution dynamic nuclear polarization (RD-DNP) technique was used to hyperpolarize [1,4- 13 C]fumarate, which was injected into concentrated hemolysates. The kinetic data were analyzed using recently developed FmR α analysis and modeling of the enzymatic reaction using Michaelis-Menten equations. In RD-DNP experiments, the decline in the 13 C-NMR signal from fumarate, and the concurrent rise and fall of that from malate, were captured with high spectral resolution and signal-to-noise ratio, which allowed the robust quantification of fumarase kinetics. The kinetic parameters obtained indicate the potential contribution of hemolysis to the overall rate of the fumarase reaction when 13 C-NMR RD-DNP is used to detect necrosis in animal models of implanted tumors. The analytical procedures developed will be applicable to studies of other rapid enzymatic reactions using conventional and hyperpolarized substrate NMR spectroscopy. Copyright © 2018 John Wiley & Sons, Ltd.

  20. Detection of human muscle glycogen by natural abundance 13C NMR

    International Nuclear Information System (INIS)

    Avison, M.J.; Rothman, D.L.; Nadel, E.; Shulman, R.G.

    1988-01-01

    Natural abundance 13 C nuclear magnetic resonance spectroscopy was used to detect signals from glycogen in the human gastrocnemius muscle. The reproducibility of the measurement was demonstrated, and the ability to detect dynamic changes was confirmed by measuring a decrease in muscle glycogen levels after exercise and its subsequent repletion. Single frequency gated 1 H decoupling was used to obtain decoupled natural abundance 13 C NMR spectra of the C-1 position of muscle glycogen

  1. Differential cross section measurement of radiative capture of protons by nuclei 13C

    International Nuclear Information System (INIS)

    Baktibayev, M.K.; Burminskii, V.P.; Burtebayev, N.; Jazairov-Kakhramanov, V.; Kadyrzhanov, K.K.; Sagindykov, Sh.Sh.; Zarifov, R.A.; Zazulin, D.M.

    2004-01-01

    The reaction 13 C(p,γ ) 14 N is the important one for the astrophysics, not only for nuclear synthesis of CNO elements, but also for nuclear synthesis of elements participating in subsequent combustion of helium [1]. The predominant yield of the reaction occurs at protons energies of less than 1 MeV. However, the clearness of the capture mechanism in this energy region is made difficult because of the superposition of the contribution of the low - energy part of the resonance 1320 keV onto the cross section. Last experimental data for a wider energy region, informed in the work [1], and results of previous works, mentioned in that work, give reason for further continuation of the study of the reaction 13 C(p,γ ) 14 N. Measured data of the work [1] in the region of E P = (320 - 900) keV at the angles of 0 o and 90 o are obviously insufficient. In the present work measurements of differential cross sections of the reaction were carried out at protons energies E P = 991 - 365 keV, the accuracy is not worse than 10%. There was studied the most (from the astrophysical point of view) important process of protons capture by 13 C nuclei onto the ground state of the 14 N nucleus. The theoretical investigation of the given reaction included calculation of cross sections. The cross sections were calculated within the framework of model of direct capture with the using of optical potentials for the description of a channel of scattering. The wave functions of a bound state were generated in a potential reproducing binding energy of a proton in 14 N nucleus. Results of calculations were compared with the experimental data. (author)

  2. The α-helical C-terminal domain of full-length recombinant PrP converts to an in-register parallel β-sheet structure in PrP fibrils: evidence from solid state nuclear magnetic resonance.

    Science.gov (United States)

    Tycko, Robert; Savtchenko, Regina; Ostapchenko, Valeriy G; Makarava, Natallia; Baskakov, Ilia V

    2010-11-09

    We report the results of solid state nuclear magnetic resonance (NMR) measurements on amyloid fibrils formed by the full-length prion protein PrP (residues 23−231, Syrian hamster sequence). Measurements of intermolecular 13C−13C dipole−dipole couplings in selectively carbonyl-labeled samples indicate that β-sheets in these fibrils have an in-register parallel structure, as previously observed in amyloid fibrils associated with Alzheimer’s disease and type 2 diabetes and in yeast prion fibrils. Two-dimensional 13C−13C and 15N−13C solid state NMR spectra of a uniformly 15N- and 13C-labeled sample indicate that a relatively small fraction of the full sequence, localized to the C-terminal end, forms the structurally ordered, immobilized core. Although unique site-specific assignments of the solid state NMR signals cannot be obtained from these spectra, analysis with a Monte Carlo/simulated annealing algorithm suggests that the core is comprised primarily of residues in the 173−224 range. These results are consistent with earlier electron paramagnetic resonance studies of fibrils formed by residues 90−231 of the human PrP sequence, formed under somewhat different conditions [Cobb, N. J., Sonnichsen, F. D., McHaourab, H., and Surewicz, W. K. (2007) Proc. Natl. Acad. Sci. U.S.A. 104, 18946−18951], suggesting that an in-register parallel β-sheet structure formed by the C-terminal end may be a general feature of PrP fibrils prepared in vitro.

  3. Solid-state 13C magic angle spinning NMR spectroscopy characterization of particle size structural variations in synthetic nanodiamonds

    International Nuclear Information System (INIS)

    Alam, Todd M.

    2004-01-01

    Solid-state 13 C magic angle spinning (MAS) NMR spectroscopy has been used to quantify the different carbon species observed in synthetically produced nanodiamonds. Two different diamond-like carbon species were observed using 13 C MAS NMR, which have been attributed to a highly ordered crystalline diamond phase and a disordered crystalline diamond phase. The relative ratio of these different diamond phases was found to vary with the particle size of the nanodiamond materials

  4. 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.

  5. 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.

  6. Multi-cluster dynamics in CΛ13 and analogy to clustering in 12C

    Directory of Open Access Journals (Sweden)

    Y. Funaki

    2017-10-01

    Full Text Available We investigate structure of CΛ13 and discuss the difference and similarity between the structures of C12 and CΛ13 by answering the questions if the linear-chain and gaslike cluster states, which are proposed to appear in C12, survives, or new structure states appear or not. We introduce a microscopic cluster model called, Hyper-Tohsaki–Horiuchi–Schuck–Röpke (H-THSR wave function, which is an extended version of the THSR wave function so as to describe Λ hypernuclei. We obtained two bound states and two resonance (quasi-bound states for Jπ=0+ in CΛ13, corresponding to the four 0+ states in C12. However, the inversion of level ordering between the spectra of C12 and CΛ13, i.e. that the 03+ and 04+ states in CΛ13 correspond to the 04+ and 03+ states in C12, respectively, is shown to occur. The additional Λ particle reduces sizes of the 02+ and 03+ states in CΛ13 very much, but the shrinkage of the 04+ state is only a half of the other states, in spite of the fact that attractive Λ-N interaction makes nucleus contracted so much when the Λ particle occupies an S-orbit. In conclusion, the Hoyle state becomes quite a compact object with BeΛ9+α configuration in CΛ13 and is no more gaslike state composed of the 3α clusters. Instead, the 04+ state in CΛ13, coming from the C12(03+ state, appears as a gaslike state composed of α+α+Λ5He configuration, i.e. the Hoyle analog state. A linear-chain state in a Λ hypernucleus is for the first time predicted to exist as the 03+ state in CΛ13 with more shrunk arrangement of the 3α clusters along z-axis than the 3α linear-chain configuration realized in the C12(04+ state. All the excited states are shown to appear around the corresponding cluster-decay threshold, reflecting the threshold rule.

  7. Detailed {sup 1}H and {sup 13}C NMR spectral data assignment for two dihydrobenzofuran neolignans

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Talita C.T.; Dias, Herbert J.; Crotti, Antônio E.M., E-mail: millercrotti@ffclrp.usp.br [Universidade de São Paulo (USP), Ribeirão Preto, SP (Brazil). Faculdade de Filosofia, Ciências e Letras. Departamento de Química

    2016-07-01

    In this work we present a complete proton ({sup 1}H) and carbon 13 ({sup 13}C) nuclear magnetic resonance (NMR) spectral analysis of two synthetic dihydrofuran neolignans (±)-trans-dehydrodicoumarate dimethyl ester and (±)-trans-dehydrodiferulate dimethyl ester. Unequivocal assignments were achieved by 1 H NMR, proton decoupled {sup 13}C ({sup 13}C{"1H}) NMR spectra, gradient-selected correlation spectroscopy (gCOSY), J-resolved, gradient-selected heteronuclear multiple quantum coherence (gHMQC), gradient-selected heteronuclear multiple bond coherence (gHMBC) and nuclear Overhauser effect spectroscopy (NOESY) experiments. All hydrogen coupling constants were measured, clarifying all the hydrogen signals multiplicities. Computational methods were also used to simulate the {sup 1}H and {sup 13}C chemical shifts and showed good agreement with the trans configuration of the substituents at C{sub 7} and C{sub 8}. (author)

  8. Near-threshold charged pion photoproduction from 13C

    International Nuclear Information System (INIS)

    LeRose, J.J.

    1981-01-01

    Differential cross sections to discrete final states have been measured for both positive and negative pion photo-production on 13 C at 90 0 in the lab at pion energies of 18, 29, and 41 MeV. Measurements were made using a fixed angle magnetic spectrometer located in the 14 0 area of the MIT Bates linear accelerator. Pions were detected using a 90 channel multi-wire proportional counter in the focal plane along with a backup array consisting of three 1/16'' thick plastic scintillator detectors and a 1/2'' thick Cerenkov detector. Positive pion photo-production cross sections were obtained for the excitation of the 3/2 - ground state and for the 3.45 MeV first excited state of 13 B. Negative pion photo-production cross sections were obtained for the excitation of the 1/2 - ground state, and the 3/2 to 3.51 MeV and 5/2 to 7.39 MeV excited states of 13 N. The measured positive pion photo-production ground state cross sections are in reasonable agreement wth theoretical calculations. However, there is a large discrepancy between the measured negative pion photoproduction ground state cross sections and the theoretical values. There are no theoretical calculations available for comparison with the excited state measurements in either positive or negative pion photoproduction on 13 C

  9. Evaluation of carbon transfers in cattle and humans using 13C

    International Nuclear Information System (INIS)

    Masuda, Tsuyoshi; Tako, Yasuhiro; Nakamura, Yuji

    2010-01-01

    In the safety assessment made around the spent nuclear fuel reprocessing plant in Rokkasho, Aomori, among radioactive nuclides released from the plant, 14 C is expected to be the largest contributor to radiation dose received by the neighboring population through agricultural and dairy products. The objectives of this study are to clarify the transfer of 14 C from grass to beef and milk and its metabolism in the human body experimentally. (1) 13 C-labeled grass was fed for 28 days to beef cattle and cows. 13 C isotopic ratio was measured in serum and other samples including muscle of beef cattle and milk of dairy cow. The 13 C rations in milk, breath air, urine and feces decreased very rapidly within 3 day after cessation of the administration of 13 C-labeled feed. However, a slow decrease in 13 C ratio was observed in muscle and serum. (2) 13 C isotopic ratios were measured in breath air, urine, feces and serum over 16 weeks in humans who were orally administered of 13 C labeled leucine, palmitic acid, glucose, boiled rice and soymilk, respectively. Residual 13 C in their bodies experimentally observed were lower than the estimates by the ICRP metabolic model for organic carbon ingestion. (author)

  10. {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)

  11. 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

  12. Experimental investigation of vector static magnetic field detection using an NV center with a single first-shell 13C nuclear spin in diamond

    Science.gov (United States)

    Jiang, Feng-Jian; Ye, Jian-Feng; Jiao, Zheng; Jiang, Jun; Ma, Kun; Yan, Xin-Hu; Lv, Hai-Jiang

    2018-05-01

    We perform a proof-of-principle experiment that uses a single negatively charged nitrogen–vacancy (NV) color center with a nearest neighbor 13C nuclear spin in diamond to detect the strength and direction (including both polar and azimuth angles) of a static vector magnetic field by optical detection magnetic resonance (ODMR) technique. With the known hyperfine coupling tensor between an NV center and a nearest neighbor 13C nuclear spin, we show that the information of static vector magnetic field could be extracted by observing the pulsed continuous wave (CW) spectrum. Project supported by the National Natural Science Foundation of China (Grant Nos. 11305074, 11135002, and 11275083), the Key Program of the Education Department Outstanding Youth Foundation of Anhui Province, China (Grant No. gxyqZD2017080), and the Education Department Natural Science Foundation of Anhui Province, China (Grant No. KJHS2015B09).

  13. Non-flipping 13C spins near an NV center in diamond: hyperfine and spatial characteristics by density functional theory simulation of the C510[NV]H252 cluster

    Science.gov (United States)

    Nizovtsev, A. P.; Kilin, S. Ya; Pushkarchuk, A. L.; Pushkarchuk, V. A.; Kuten, S. A.; Zhikol, O. A.; Schmitt, S.; Unden, T.; Jelezko, F.

    2018-02-01

    Single NV centers in diamond coupled by hyperfine interaction (hfi) to neighboring 13C nuclear spins are now widely used in emerging quantum technologies as elements of quantum memory adjusted to a nitrogen-vacancy (NV) center electron spin qubit. For nuclear spins with low flip-flop rate, single shot readout was demonstrated under ambient conditions. Here we report on a systematic search for such stable NV-13C systems using density functional theory to simulate the hfi and spatial characteristics of all possible NV-13C complexes in the H-terminated cluster C510[NV]-H252 hosting the NV center. Along with the expected stable ‘NV-axial-13C’ systems wherein the 13C nuclear spin is located on the NV axis, we found for the first time new families of positions for the 13C nuclear spin exhibiting negligible hfi-induced flipping rates due to near-symmetric local spin density distribution. Spatially, these positions are located in the diamond bilayer passing through the vacancy of the NV center and being perpendicular to the NV axis. Analysis of available publications showed that, apparently, some of the predicted non-axial near-stable NV-13C systems have already been observed experimentally. A special experiment performed on one of these systems confirmed the prediction made.

  14. Fractional enrichment of proteins using [2-{sup 13}C]-glycerol as the carbon source facilitates measurement of excited state {sup 13}Cα chemical shifts with improved sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Ahlner, Alexandra; Andresen, Cecilia; Khan, Shahid N. [Linköping University, Division of Chemistry, Department of Physics, Chemistry and Biology (Sweden); Kay, Lewis E. [The University of Toronto, Departments of Molecular Genetics, Biochemistry and Chemistry, One King’s College Circle (Canada); Lundström, Patrik, E-mail: patlu@ifm.liu.se [Linköping University, Division of Chemistry, Department of Physics, Chemistry and Biology (Sweden)

    2015-07-15

    A selective isotope labeling scheme based on the utilization of [2-{sup 13}C]-glycerol as the carbon source during protein overexpression has been evaluated for the measurement of excited state {sup 13}Cα chemical shifts using Carr–Purcell–Meiboom–Gill (CPMG) relaxation dispersion (RD) experiments. As expected, the fractional incorporation of label at the Cα positions is increased two-fold relative to labeling schemes based on [2-{sup 13}C]-glucose, effectively doubling the sensitivity of NMR experiments. Applications to a binding reaction involving an SH3 domain from the protein Abp1p and a peptide from the protein Ark1p establish that accurate excited state {sup 13}Cα chemical shifts can be obtained from RD experiments, with errors on the order of 0.06 ppm for exchange rates ranging from 100 to 1000 s{sup −1}, despite the small fraction of {sup 13}Cα–{sup 13}Cβ spin-pairs that are present for many residue types. The labeling approach described here should thus be attractive for studies of exchanging systems using {sup 13}Cα spin probes.

  15. 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.

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

    International Nuclear Information System (INIS)

    Oettl, Sarah K.; Hubert, Jane; Nuzillard, Jean-Marc; Stuppner, Hermann; Renault, Jean-Hugues; Rollinger, Judith M.

    2014-01-01

    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 13 C NMR signals resulted in the identification of depside molecular skeletons. • 13 C chemical shift clusters were assigned to structures using a 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 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 13 C chemical shifts were assigned to their corresponding molecular structures with the help of an in-house 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), and olivetonide (6)

  17. Search for C+ C clustering in Mg ground state

    Indian Academy of Sciences (India)

    2017-01-04

    Jan 4, 2017 ... Finite-range knockout theory predictions were much larger for (12C,212C) reaction, indicating a very small 12C−12C clustering in 24Mg. (g.s.) . Our present results contradict most of the proposed heavy cluster (12C+12C) structure models for the ground state of 24Mg. Keywords. Direct nuclear reactions ...

  18. Study of solid chemical evolution in torrefaction of different biomasses through solid-state "1"3C cross-polarization/magic angle spinning NMR (nuclear magnetic resonance) and TGA (thermogravimetric analysis)

    International Nuclear Information System (INIS)

    Rodriguez Alonso, Elvira; Dupont, Capucine; Heux, Laurent; Da Silva Perez, Denilson; Commandre, Jean-Michel; Gourdon, Christophe

    2016-01-01

    The objective of this work is to compare mass loss and chemical evolution of the solid phase, versus time, during dynamic torrefaction of different types of biomass. For this purpose, two experiments, ThermoGravimetric Analysis and solid-state "1"3C Cross-Polarization/Magic Angle Spinning Nuclear Magnetic Resonance, were run on four representative biomasses. Overall mass loss and chemical evolution of the solid phase were followed, respectively, as a function of temperature and time. Thanks to this coupled information, it was shown that the knowledge of both solid mass loss and chemical evolution is necessary to characterize torrefaction severity. Moreover, biomasses containing higher proportions of xylan lost mass faster than those containing lower proportions. Lignin showed a protecting role towards cellulose, which would lead to a faster degradation of non-woody biomasses in comparison with woody biomasses. Three parameters would have an influence on solid chemical evolution during torrefaction: xylan content in hemicellulose, lignin content in biomass, and cellulose crystallinity. - Highlights: • Torrefaction of four biomasses was studied with TGA and solid-state NMR. • Both solid mass loss and chemical evolution characterize torrefaction severity. • Biomasses containing a higher proportion of xylan lose mass faster. • Lignin shows a stronger protecting role in degradation of woody biomasses. • Xylan, lignin and crystalline cellulose values influence solid chemical evolution.

  19. Determination of the percentage of quitine desacetilation reaction by solid state carbon-13 NMR; Determinacao do porcentual de reacao de desacetilacao de quitina por RMN {sup 13} C no estado solido

    Energy Technology Data Exchange (ETDEWEB)

    Ferracin, Ricardo J. [Sao Carlos Univ., SP (Brazil). Centro de Caracterizacao e Desenvolvimento; Cass, Quezia B.; Bassi, Ana L. [Sao Carlos Univ., SP (Brazil). Lab. de Sintese Organica

    1997-12-31

    Quitine is a bi-polymer largely found in invertebrates. As most compounds of this class are insoluble in common organic solvents, the des-acetylation percentile was obtained by carbon-13 solid state nuclear magnetic resonance. The methodology is presented. Results are presented 3 refs., 1 figs.

  20. The Fragmentation of Heavy Nuclei by 13.8 GeV/c Protons as a Contribution to the Study of the Interaction Mechanism and Nuclear Structure; Fragmentacion de nucleos pesados por protones de 13'8 GeV/c, como contribucion al estudio del mecanismo de interaccion y estructura nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Gil Perez, D.

    1967-07-01

    We present here an global study of the interaction between high- energy particles and heavy nuclei, an interaction which holds obvious interest in relation to the problems of nuclear fragmentation and which, up lo now has only been studied piecemeal. We have used three stacks of photographic emulsions which were irradiated by 13.8 GeV/c protons, 17 GeV/c negative pions and 24 GeV/c protons. All three irradiations took place in a 180 K.G. magnetic field using CERN beams. (Author) 20 refs.

  1. The Fragmentation of Heavy Nuclei by 13.8 GeV/c Protons as a Contribution to the Study of the Interaction Mechanism and Nuclear Structure; Fragmentacion de nucleos pesados por protones de 13'8 GeV/c, como contribucion al estudio del mecanismo de interaccion y estructura nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Gil Perez, D

    1967-07-01

    We present here an global study of the interaction between high- energy particles and heavy nuclei, an interaction which holds obvious interest in relation to the problems of nuclear fragmentation and which, up lo now has only been studied piecemeal. We have used three stacks of photographic emulsions which were irradiated by 13.8 GeV/c protons, 17 GeV/c negative pions and 24 GeV/c protons. All three irradiations took place in a 180 K.G. magnetic field using CERN beams. (Author) 20 refs.

  2. XRD and solid state 13C-NMR evaluation of the crystallinity enhancement of 13C-labeled bacterial cellulose biosynthesized by Komagataeibacter xylinus under different stimuli: A comparative strategy of analyses.

    Science.gov (United States)

    Meza-Contreras, Juan C; Manriquez-Gonzalez, Ricardo; Gutiérrez-Ortega, José A; Gonzalez-Garcia, Yolanda

    2018-05-22

    The production and crystallinity of 13 C bacterial cellulose (BC) was examined in static culture of Komagataeibacter xylinus with different chemical and physical stimuli: the addition of NaCl or cloramphenicol as well as exposure to a magnetic field or to UV light. Crystalline BC biosynthesized under each stimulus was studied by XRD and solid state 13 C NMR analyses. All treatments produced BC with enhanced crystallinity over 90% (XRD) and 80% (NMR) compared to the control (83 and 76%, respectively) or to Avicel (77 and 62%, respectively). The XRD data indicated that the crystallite size was 80-85 Å. Furthermore, changes on the allomorphs (I α and I β ) ratio tendency of BC samples addressed to the stimuli were estimated using the C4 signal from 13 C NMR data. These results showed a decrease of the allomorph I α (3%) when BC was biosynthesized with UV light and chloramphenicol compared to control (58.79%). In contrast, the BC obtained with NaCl increased up to 60.31% of the I α allomorph ratio. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Evaluation of natural rubber from IAC series clones by solid state {sup 13}C NMR; Avaliacao da borracha natural de clones da serie IAC por {sup 13}C RMN no estado solido

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Maria A.; Moreno, Rogerio M.B.; Goncalves, Paulo S. [Instituto Agronomico de Campinas, SP (Brazil). Centro de Cafe e Plantas Tropicais. Programa Seringueira]. E-mails: paulog@iac.sp.gov.br; mariaalice@cnpdia.embrapa.br; Forato, Lucimara A.; Colnago, Luiz A.; Mattoso, Luiz H.C. [EMBRAPA Instrumentacao Agropecuaria, Sao Carlos, SP (Brazil)]. E-mail: colnago@cnpdia.embrapa.br; forato@cnpdia.embrapa.br; rogerio@cnpdia.embrapa.br; mattoso@cnpdia.embrapa.br; Job, Aldo E. [Universidade Estadual Paulista (UNESP), Presidente Prudente, SP (Brazil). Departamento de Fisica, Quimica e Biologia

    2005-07-01

    Agronomic Institute (IAC) and EMBRAPA Agricultural Instrumentation (EMBRAPA/CNPDIA) have been studied Hevea species in order to increase the production of the natural rubber and to develop new clones more appropriated to Brazil's soil and climate. Structural characterization of natural rubber [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell. - Arg.] from new clones of the IAC series (IAC 300, 301, 302, 303, 35, 40, and 56) and from RRIM 600 clone has been studied by high-resolution solid-state {sup 13}C NMR and by single pulse technique. The results have shown that the application of solid-state {sup 13}C NMR using the single pulse technique is a powerful tool to study natural rubber. The spectra obtained through this technique confirmed that natural rubber from all clones studied are cis-1,4-polyisoprene (author) form.(author)

  4. Applications of the nuclear Techniques in medicine: 13C or 14C respiration tests

    International Nuclear Information System (INIS)

    Rivero Santamaria, Alejandro

    2008-01-01

    The 14 C or 13 C respiration tests have been applied to the study of metabolic and infectious processes, but most of them have not entered yet the clinical practice stage. In this paper, it is offered an overview of the present and future of respiration tests and how they are taking part and will take part in a future in the non-invasive diagnosis of diverse pathologies

  5. Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves

    Energy Technology Data Exchange (ETDEWEB)

    Thurber, Kent R., E-mail: thurberk@niddk.nih.gov; Tycko, Robert [Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520 (United States)

    2014-05-14

    We report solid state {sup 13}C and {sup 1}H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, {sup 1}H and cross-polarized {sup 13}C NMR signals from {sup 15}N,{sup 13}C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T{sub 1e} is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations.

  6. Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves

    International Nuclear Information System (INIS)

    Thurber, Kent R.; Tycko, Robert

    2014-01-01

    We report solid state 13 C and 1 H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, 1 H and cross-polarized 13 C NMR signals from 15 N, 13 C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T 1e is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations

  7. Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves.

    Science.gov (United States)

    Thurber, Kent R; Tycko, Robert

    2014-05-14

    We report solid state (13)C and (1)H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, (1)H and cross-polarized (13)C NMR signals from (15)N,(13)C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T1e is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations.

  8. 13C solid state NMR investigation of natural resins components

    International Nuclear Information System (INIS)

    Tavares, Maria I.B.; Bathista, Andre L.B.S.; Silva, Emerson O.; Priante Filho, Nicolau; Nogueira, Jose S.

    2001-01-01

    The objective of this work is to establish and analytical methodology as a routine using solid state nuclear magnetic resonance (NMR) techniques to investigate the mainly chemical components presented in natural resins in bulk. And also to evaluate the molecular behaviour of these resins. The routine solid state techniques allow us to assign the main compounds presented in the resins. Therefore, applying specialised techniques, like variable contact time, delayed contact time, dephasing time and proton spin lattice relaxation time in the rotating frame (T 1 H ρ), more information about chemical structure and molecular dynamic is available

  9. Study of the metabolism of 13C labeled substrates by 13C NMR spectroscopy of intact cells, tissues, and organs

    International Nuclear Information System (INIS)

    Matwiyoff, N.A.; London, R.E.; Hutson, J.Y.

    1982-01-01

    Carbon-13 nuclear magnetic resonance spectroscopy, in conjunction with carbon-13 labeling, has become an important analytical technique for the study of biological systems and biologically important molecules. The growing list of its well established applications to isolated molecules in solution includes the investigation of: metabolic pathways; the microenvironments of ligands bound to proteins; the architecture and dynamics of macromolecules; the structures of coenzymes and other natural products; and the mechanisms of reactions. Recently interest has been reawakened in the use of the technique for the study of metabolic pathways and structural components in intact organelles, cells, and tissues. The promise and problems in the use of 13 C labeling in such investigations can be illustrated by the results on suspensions of the yeast, Candida utilis

  10. Fourier spectroscopy of the 12C2, 13C2, and 12C13C (0-0) swan bands

    International Nuclear Information System (INIS)

    Amiot, C.

    1983-01-01

    The (0-0) band of the C 2 Swan electronic system d 3 Pi/sub g/→a 3 Pi/sub u/ has been recorded by Fourier spectroscopy. The three isotopes species 12 C 2 , 13 C 2 , and 12 C 13 C were investigated. The observed wavenumbers were reduced to molecular parameters using a nonlinear least-square fitting procedure. Well-known perturbations at N' = 47 and N' = 51 again observed in the e 12 C 2 d 3 Pi/sub g/ (v = 0) level. Perturbations of the same kind are present in the 13 C 2 spectrum at N' = 34 and N' = 44,48,52. The 12 C 13 C spectrum exhibits in the observed spectral range a unique perturbation for N' = 41

  11. 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

  12. Proline metabolism in the wild-type and in a salt-tolerant mutant of nicotiana plumbaginifolia studied by (13)C-nuclear magnetic resonance imaging

    Science.gov (United States)

    Roosens; Willem; Li; Verbruggen; Biesemans; Jacobs

    1999-12-01

    To obtain insight into the link between proline (Pro) accumulation and the increase in osmotolerance in higher plants, we investigated the biochemical basis for the NaCl tolerance of a Nicotiana plumbaginifolia mutant (RNa) that accumulates Pro. Pro biosynthesis and catabolism were investigated in both wild-type and mutant lines. (13)C-Nuclear magnetic resonance with [5-(13)C]glutamate (Glu) as the Pro precursor was used to provide insight into the mechanism of Pro accumulation via the Glu pathway. After 24 h under 200 mM NaCl stress in the presence of [5-(13)C]Glu, a significant enrichment in [5-(13)C]Pro was observed compared with non-stress conditions in both the wild type (P2) and the mutant (RNa). Moreover, under the same conditions, [5-(13)C]Pro was clearly synthesized in higher amounts in RNa than in P2. On the other hand, measurements of enzyme activities indicate that neither the biosynthesis via the ornithine pathway, nor the catabolism via the Pro oxidation pathway were affected in the RNa mutant. Finally, the regulatory effect exerted by Pro on its biosynthesis was evaluated. In P2 plantlets, exogenous Pro markedly reduced the conversion of [5-(13)C]Glu into [5-(13)C]Pro, whereas Pro feedback inhibition was not detected in the RNa plantlets. It is proposed that the origin of tolerance in the RNa mutant is due to a mutation leading to a substantial reduction of the feedback inhibition normally exerted in a wild-type (P2) plant by Pro at the level of the Delta-pyrroline-5-carboxylate synthetase enzyme.

  13. Millimetre-wave spectrum of anti-13C1 and 13C2 isotopologues of ethanol

    International Nuclear Information System (INIS)

    Bouchez, Aurelia; Walters, Adam; Müller, Holger S.P.; Ordu, Matthias; Lewen, Frank; Koerber, Monika; Bottinelli, Sandrine; Endres, Christian P.; Schlemmer, Stephan

    2012-01-01

    The rotational spectra of the two monosubstituted 13 C isotopologues of the anti conformer of ethanol have been measured between 80-800 GHz using three different spectrometers at the Cologne Laboratory Astrophysics group. The dataset was constrained for fitting with a standard Watson-S reduction Hamiltonian by rejecting transitions from high-lying states showing significant perturbation with the gauche states and by averaging some small methyl torsional splits. This treatment is compatible with the needs for a first astrophysical research for which an appropriate set of predictions is given.

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

    Science.gov (United States)

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

    2010-01-01

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

  15. Nanoscale quantum gyroscope using a single 13C nuclear spin coupled with a nearby NV center in diamond

    Science.gov (United States)

    Song, Xuerui; Wang, Liujun; Feng, Fupan; Lou, Liren; Diao, Wenting; Duan, Chongdi

    2018-03-01

    Developing gyroscopes based on quantum systems are important for inertial sensing applications, and its underlying physics is of fundamental interest. In this paper, we proposed a new type of gyroscope based on the Berry phase generated during rotation of the quantum system by using a single 13C nuclear spin coupled with a nearby nitrogen-vacancy center in diamond. Due to the atom-scale size of the quantum system, rotation information can be obtained with high spatial resolution. The gyroscope can be manipulated at room temperature and without the need for a strong magnetic field, which is also beneficial to its further applications.

  16. Synthesis of [2-13C, 2-14C] 2-aminoethanol, [1-13C, 1-14C] 2-chloroethylamine, N,N'-bis([1-13C, 1-14C] 2-chloroethyl)-N-nitrosourea(BCNU) and N-([1-13C, 1-14C] 2-chloroethyl)-N-nitrosourea(CNU)

    International Nuclear Information System (INIS)

    Narayan, R.; Chang, C-j.

    1982-01-01

    [2- 13 C, 2- 14 C]2-Aminoethanol hydrochloride was prepared in good yield from Na*CN in a two step sequence by first converting the Na*CN to OHCH 2 *CN and then reducing the nitrile directly with a solution of borane-tetrahydrofuran complex. The reaction procedure was simple and the pure product could be obtained readily. Using this specifically labelled precursor, the synthesis of [1- 13 C, 1- 14 C]2-chloroethylamine hydrochloride, N-([1- 13 C, 1- 14 C]2-chloroethyl)-N-nitrosourea(CNU) and N,N'-bis([1- 13 C, 1- 14 C]2-chloroethyl)-N-nitrosourea(BCNU) in good yield without isotope scrambling was also reported. (author)

  17. The 12C/13C Isotopic Ratio in Planetary Nebulae as Deduced from IUE Data

    Science.gov (United States)

    Miskey, C. L.; Feibelman, W. A.; Bruhweiler, F. C.

    2000-05-01

    The relative abundances of C, N, and O and the isotopic ratio of 12C/13C represent tracers of nucleosynthesis in intermediate stars with main-sequence masses between 0.6 and 8.0 solar masses in our Galaxy. Determining these abundances and the isotopic 12C/13C ratio in planetary nebulae (PNe) represent perhaps the best means to discern exactly how the ISM is enriched by CNO stellar nucleosynthesis. Walsh et al. (1996) and Clegg et al. (1997), using the Hubble Space Telescope, have derived the isotopic 12C/13C abundance ratio in the galactic carbon-rich PN, NGC 3918, and placed marginal constraints on it for the Magellanic PNe, N2 (SMC) and N122 (LMC). This was done using the well-known 12C 3P-1S (J=1-0 and J=2-0) transitions of C+2 at 1906.68 Angstroms and 1908.77 Angstroms and a J=0-0 transition at 1909.6 Angstroms, which is strictly forbidden in 12C. The finite nuclear spin of 13C (I=1/2) permits a corresponding F=1/2-1/2 electric dipole transition not seen in 12C. Since the 1909.6 Angstroms line is well separated from the other two 12C transitions, it provides an important means of determining 12C/13C in planetary nebulae. We have just completed a search of archival International Ultraviolet Explorer (IUE) high-dispersion spectra of approximately three dozen PNe, and derived 12C/13C ratios of 39 and 23 for the galactic PNe, NGC 2440 and NGC 6302, respectively. These are values much lower than the solar value of 89. In the other objects, the limited S/N of the IUE data indicate 12C/13C ratio upper limits much higher than 50. The implications of these results and their pertinence to stellar evolution are discussed.

  18. 13C nuclear magnetic resonance data of lanosterol derivatives—Profiling the steric topology of the steroid skeleton via substituent effects on its 13C NMR

    Science.gov (United States)

    Dias, Jerry Ray; Gao, Hongwu

    2009-12-01

    The 13C NMR spectra of over 24 tetracyclic triterpenoid derivatives have been structurally analyzed. The 13C NMR chemical shifts allow one to probe the steric topology of the rigid steroid skeleton and inductive effects of its substituents. Use of deuterium labeling in chemical shift assignment and B-ring aromatic terpenoids are also featured.

  19. 13C and 18O isotope enrichment by vibrational energy exchange pumping of CO

    International Nuclear Information System (INIS)

    Bergman, R.C.; Homicz, G.F.; Rich, J.W.; Wolk, G.L.

    1983-01-01

    Measurements of preferential vibration-to-vibration (V--V) pumping of high vibrational states of 13 C 16 O and 12 C 18 O in optically excited CO gas are reported. It is found that the v = 22, 25, 27, 30, and 32 states of 13 C 16 O and the v = 8, 10, and 12 states of 12 C 18 O are substantially overpopulated compared to the same states in 12 C 16 O in strongly V--V pumped CO. Such mixtures are observed to react, forming products enriched in 13 C. The results are in reasonable agreement with an analytical kinetic model of V--V pumping in binary mixtures of diatomic gases

  20. Present state of nuclear power business in China

    International Nuclear Information System (INIS)

    Morokuzu, Muneo

    2011-01-01

    This article presented present state of nuclear power business in China based on latest information obtained at visit at nuclear power related facilities in December 2010. China Atomic Energy Authority (CAEA) promoted nuclear power, while National Nuclear Safety Administration (NNSA) was an independent regulatory body of nuclear power. Construction of nuclear power was promoted by three national nuclear engineering development corporations: China National Nuclear Corporation (CNNC), China Guangdon Nuclear Power Corporation (CGNPC) and State Nuclear Power Technology Corporation (SNPTC). In China, 13 nuclear power reactors were in operation and 27 under construction. Shortage of nuclear engineers became evident with rapid growth of nuclear power, which forced delay of nuclear power construction schedule. Future strategies of reactor type varied domestic, French and US ones respectively dependent on CNNC, CGNPC and SNPTC, CNNC seemed to change from third generation reactor (CNP 1000) to second one (CP 1000) due to regulatory licensing difficulty of NNSA. As for advanced reactor development, large scale PWR project, HTR project and FBR development project were proceeding. As HTR project was selected as high-priority project, an experimental reactor (HTR-10) was critical in 2000 and construction of demonstration reactor started in 2009. (T. Tanaka)

  1. Quantitative evaluation of the biosynthetic pathways leading to δ-aminolevulinic acid from the Shemin precursor glycine via the C5 pathway in Arthrobacter hyalinus by analysis of 13C-labeled coproporphyrinogen III biosynthesized from [2-13C]glycine, [1-13C]acetate, and [2-13C]acetate using 13C NMR spectroscopy

    International Nuclear Information System (INIS)

    Katsumi Iida

    2013-01-01

    The biosynthetic pathways leading to δ-aminolevulinic acid (ALA) from the Shemin precursor glycine via the C5 pathway in Arthrobacter hyalinus were quantitatively evaluated by means of feeding experiments with [2- 13 C]glycine, sodium [1- 13 C]acetate, and sodium [2- 13 C]acetate, followed by analysis of the labeling patterns of coproporphyrinogen III (Copro'gen III) (biosynthesized from ALA) using 13 C NMR spectroscopy. Two biosynthetic pathways leading to ALA from glycine via the C5 pathway were identified: i.e., transformation of glycine to l-serine catalyzed by glycine hydroxymethyltransferase, and glycine synthase-catalyzed catabolism of glycine to N 5 , N 10 -methylene-tetrahydrofolic acid (THF), which reacts with another molecule of glycine to afford l-serine. l-Serine is transformed to acetyl-CoA via pyruvic acid. Acetyl-CoA enters the tricarboxylic acid cycle, affording 2-oxoglutaric acid, which in turn is transformed to l-glutamic acid. The l-glutamic acid enters the C5 pathway, affording ALA in A. hyalinus. A 13 C NMR spectroscopic comparison of the labeling patterns of Copro'gen III obtained after feeding of [2- 13 C]glycine, sodium [1- 13 C]acetate, and sodium [2- 13 C]acetate showed that [2- 13 C]glycine transformation and [2- 13 C]glycine catabolism in A. hyalinus proceed in the ratio of 52 and 48 %. The reaction of [2- 13 C]glycine and N 5 , N 10 -methylene-THF, that of glycine and N 5 , N 10 -[methylene- 13 C]methylene-THF generated from the [2- 13 C]glycine catabolism, and that of [2- 13 C]glycine and N 5 , N 10 -[methylene- 13 C]methylene-THF transformed the fed [2- 13 C]glycine to [1- 13 C]acetyl-CoA, [2- 13 C]acetyl-CoA, and [1,2- 13 C 2 ]acetyl-CoA in the ratios of 42, 37, and 21 %, respectively. These labeled acetyl-CoAs were then incorporated into ALA. Our results provide a quantitative picture of the pathways of biosynthetic transformation to ALA from glycine in A. hyalinus. (author)

  2. Synthesis of (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)olivetolic acid, methyl (1'-/sup 13/C)olivetolate and (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)cannabigerolic acid

    Energy Technology Data Exchange (ETDEWEB)

    Porwoll, J P; Leete, E [Minnesota Univ., Minneapolis (USA). Dept. of Chemistry

    1985-03-01

    Potential advanced intermediates in the biosynthesis of delta/sup 9/-tetrahydrocannabinol, the major psychoactive principle of marijuana, have been synthesized labeled with two contiguous /sup 13/C atoms and /sup 14/C. Methyl (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)olivetolate was prepared from lithium (/sup 13/C/sub 2/)acetylide and dimethyl (2-/sup 14/C)malonate. Reaction with geranyl bromide afforded methyl (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)cannabigerolate, and hydrolysis of these methyl esters with lithium propyl mercaptide yielded the corresponding labeled acids. The /sup 13/C-/sup 13/C couplings observable in the /sup 13/C NMR spectra of these /sup 13/C-enriched compounds and their synthetic precursors are recorded. Methyl (1'-/sup 14/C)olivetolate was prepared from /sup 13/CO/sub 2/ to confirm assignments of the /sup 13/C chemical shifts in the pentyl side chain of these compounds.

  3. Synthesis of C-13 labeled vitamin E, [4' a-13C]all-rac-α-tocopherol

    International Nuclear Information System (INIS)

    Urano, Shiro; Muto, Riko; Matsuo, Mitsuyoshi

    1985-01-01

    Vitamin E with a 13 C-labeled isoprenoid side chain, [4' a- 13 C]-all-rac-α-tocopherol, was synthesized by the coupling reaction of 6-4-methoxymethoxy-2-([methyl- 13 C]5-bromo-4-methyl-pent-1-yl)chroman (8) with 3,7-dimethyl-1-(thiazolin-2-yl)thio-2,6-octadiene. Compound 8 was prepared using 2-(4,4-di-ethoxycarbonylbut-1-yl)-6-methoxymethoxy-2,5,7,8-tetramethyl-chroman as a key intermediate and [ 13 C]methyl iodide as a 13 C source. The total yield of the labeled α-tocopherol based on [ 13 C]methyl iodide was 58.7%. (author)

  4. Monovacancy paramagnetism in neutron-irradiated graphite probed by 13C NMR.

    Science.gov (United States)

    Zhang, Z T; Xu, C; Dmytriieva, D; Molatta, S; Wosnitza, J; Wang, Y T; Helm, M; Zhou, Shengqiang; Kühne, H

    2017-10-20

    We report on the magnetic properties of monovacancy defects in neutron-irradiated graphite, probed by 13 C nuclear magnetic resonance spectroscopy. The bulk paramagnetism of the defect moments is revealed by the temperature dependence of the NMR frequency shift and spectral linewidth, both of which follow a Curie behavior, in agreement with measurements of the macroscopic magnetization. Compared to pristine graphite, the fluctuating hyperfine fields generated by the defect moments lead to an enhancement of the 13 C nuclear spin-lattice relaxation rate [Formula: see text] by about two orders of magnitude. With an applied magnetic field of 7.1 T, the temperature dependence of [Formula: see text] below about 10 K can well be described by a thermally activated form, [Formula: see text], yielding a singular Zeeman energy of ([Formula: see text]) meV, in excellent agreement with the sole presence of polarized, non-interacting defect moments.

  5. Proline Metabolism in the Wild-Type and in a Salt-Tolerant Mutant of Nicotiana plumbaginifolia Studied by 13C-Nuclear Magnetic Resonance Imaging1

    Science.gov (United States)

    Roosens, Nancy H.; Willem, Rudolph; Li, Yan; Verbruggen, Ingrid; Biesemans, Monique; Jacobs, Michel

    1999-01-01

    To obtain insight into the link between proline (Pro) accumulation and the increase in osmotolerance in higher plants, we investigated the biochemical basis for the NaCl tolerance of a Nicotiana plumbaginifolia mutant (RNa) that accumulates Pro. Pro biosynthesis and catabolism were investigated in both wild-type and mutant lines. 13C-Nuclear magnetic resonance with [5-13C]glutamate (Glu) as the Pro precursor was used to provide insight into the mechanism of Pro accumulation via the Glu pathway. After 24 h under 200 mm NaCl stress in the presence of [5-13C]Glu, a significant enrichment in [5-13C]Pro was observed compared with non-stress conditions in both the wild type (P2) and the mutant (RNa). Moreover, under the same conditions, [5-13C]Pro was clearly synthesized in higher amounts in RNa than in P2. On the other hand, measurements of enzyme activities indicate that neither the biosynthesis via the ornithine pathway, nor the catabolism via the Pro oxidation pathway were affected in the RNa mutant. Finally, the regulatory effect exerted by Pro on its biosynthesis was evaluated. In P2 plantlets, exogenous Pro markedly reduced the conversion of [5-13C]Glu into [5-13C]Pro, whereas Pro feedback inhibition was not detected in the RNa plantlets. It is proposed that the origin of tolerance in the RNa mutant is due to a mutation leading to a substantial reduction of the feedback inhibition normally exerted in a wild-type (P2) plant by Pro at the level of the Δ-pyrroline-5-carboxylate synthetase enzyme. PMID:10594115

  6. Curing reactions of bismaleimide resins catalyzed by triphenylphosphine. High resolution solid-state 13C NMR study

    International Nuclear Information System (INIS)

    Shibahara, Sumio; Enoki, Takashi; Yamamoto, Takahisa; Motoyoshiya, Jiro; Hayashi, Sadao.

    1996-01-01

    The curing reactions of bismaleimide resins consisted of N,N'-4,4'-diphenylmethanebismaleimide (BMI) and o,o'-diallylbisphenol-A (DABA) in the presence of triphenylphosphine (TPP) as a catalyst were investigated. DSC measurements showed that the catalytic effect of TPP on the curing reaction of BMI was more in the presence of DABA than in its absence. In order to explore this curing reaction, N-phenylmaleimide (PMI) and o-allylphenol (AP) were selected as model compounds. The products of the PMI/TPP system were oligomers and polymers of PMI, whereas the main product of the PMI/AP/TPP system was the PMI trimer which had the five-membered ring formed via the phosphonium ylide intermediate. In these model reactions, 13 C NMR was found to be useful to distinguish between trimerization and polymerization of PMI. On the basis of the results of the model reactions, the curing reactions of bismaleimide resins were investigated by high resolution solid state 13 C NMR techniques. In the BMI/TPP system, maleimides polymerize above 175degC, but the polymerization does not proceed at 120degC. On the other hand, maleimides trimerize above 120degC in the presence of DABA and TPP. The mechanism of the trimerization is briefly discussed. (author)

  7. Synthesis of (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)olivetolic acid, methyl (1'-/sup 13/C)olivetolate and (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)cannabigerolic acid

    Energy Technology Data Exchange (ETDEWEB)

    Porwoll, J.P.; Leete, E. (Minnesota Univ., Minneapolis (USA). Dept. of Chemistry)

    1985-03-01

    Potential advanced intermediates in the biosynthesis of delta/sup 9/-tetrahydrocannabinol, the major psychoactive principle of marijuana, have been synthesized labeled with two contiguous /sup 13/C atoms and /sup 14/C. Methyl (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)olivetolate was prepared from lithium (/sup 13/C/sub 2/)acetylide and dimethyl (2-/sup 14/C)malonate. Reaction with geranyl bromide afforded methyl (5,6-/sup 13/C/sub 2/, 1-/sup 14/C)cannabigerolate, and hydrolysis of these methyl esters with lithium propyl mercaptide yielded the corresponding labeled acids. The /sup 13/C-/sup 13/C couplings observable in the /sup 13/C NMR spectra of these /sup 13/C-enriched compounds and their synthetic precursors are recorded. Methyl (1'-/sup 14/C)olivetolate was prepared from /sup 13/CO/sub 2/ to confirm assignments of the /sup 13/C chemical shifts in the pentyl side chain of these compounds.

  8. Structure of 14C via elastic and inelastic neutron scattering from 13C: Measurement, R-matrix analysis, and shell model calculations

    International Nuclear Information System (INIS)

    Resler, D.A.

    1987-03-01

    The specific purpose of this work is to provide a better understanding of the 14 C level structure; the general purpose is to provide the details for using shell model calculations in R-matrix analyses. Using the TOF facilities of the Ohio University Accelerator Laboratory, the elastic and first 3 inelastic differential scattering cross sections for 13 C + n were measured at 69 energies for 4.5 ≤ E/sub n/ ≤ 11 MeV. A multiple scattering code was developed which provided a simulation of the experimental scattering process allowing accurate corrections to the small inelastic data. The integrated 13 C(n,α) 10 Be cross section is estimated. The sequential 2n-decay of 14 C states populated by 13 C + n was observed. A shell model code was developed. Normal and nonnormal parity calculations were made for the lithium isotopes using a new two-body interaction. The results for 5 Li predict the 2s/sub 1/2/ and 1d/sub 5/2/ single-particle states to be located below the 3/2 + state. Similar calculations were made for 13 C, 13 N, and 14 C. Results for 13 C and 13 N show for E/sub x/ 7 Li and 14 C, 2 h-barω calculations were done. Shell model calculations generated the R-matrix parameters for the elastic and first 3 inelastic channels of 13 C + n. After adjusting some energies, the predicted structure generally agrees with experiment for E/sub n/ 13 C + n data were refit to replace R 0 background terms by more realistic broad states and to get better agreement with model calculations. R-matrix fitting of the full data set produced new 14 C level information. For E/sub n/ > 4 MeV (E/sub x/ > 12 MeV), 5 states are given definite J/sup π/ assignments; 3, tentative assignments. 122 refs., 91 figs., 30 tabs

  9. Experimental study of radiative pion capture on 13C, 20Ne, 90Zr, 19F and 12C

    International Nuclear Information System (INIS)

    Martoff, C.J.

    1980-11-01

    Photon spectra for 50 13 C, 19 F, 20 Ne, and 90 Zr. The e + e - pair spectrometer system used has resolution 850 keV fwhm and photon detection efficiency 5 x 10 -6 . The total radiative capture branching ratios measured are 13 C (1.66 +- 0.25)%, 19 F (2.40 +- 0.48)%, 20 Ne (1.60 +- 0.24)%, and 90 Zr (2.1 +- 0.5)%. The partial radiative capture branching ratios to four bound states and two resonances in 20 F, and two bound states and three resonances in 13 B have also been measured. The branching ratio for 13 C(π - ,γ) 13 B g.s. is (6.1 +- 1.2) x 10 -4 . Comparison of this result with the beta decay rate of 13 B shows that (84 +- 16)% of the pion capture amplitude is accounted for by the Gamow-Teller matrix element. Further analysis suggests that much of the remaining strength is E2. The measured branching ratios to resonant states in 13 C(π - ,γ) 13 B are shown to be in agreement with detailed shell model calculations. The total single-particle strength in these transitions is shown to be approximately half as large as that of the T = 3/2 part of the E1 photoresonance (the Giant Dipole Resonance) in 13 C. The branching ratio for 20 Ne(π - ,γ) 20 F (T = 1, J/sup π/ = 1 + , E/sub x/ = 1.06 MeV) is 0.91 +- 0.52).10 -4 . Comparison with the electroexcitation of the analog giant M1 state in 20 Ne (11.24 MeV) shows that the M1 transition amplitude is less than (46 +- 14)% Gamow-Teller. This result is in agreement with detailed shell model calculations of the M1 transition. The photon spectrum for radiative pion capture from flight (reaction 12 C(π + T = 44 MeV, γ at 90 0 )) has been measured. 13 figures, 12 tables

  10. Extension of responsibilities of the State Office for Nuclear Safety

    International Nuclear Information System (INIS)

    Hrehor, M.

    1995-01-01

    The responsibilities of the State Office for Nuclear Safety have been extended by Act No. 85/1995 to cover protection against ionizing radiation. The following responsibilities of the State Office for Nuclear Safety are defined by the Act: a) state surveillance over nuclear safety of nuclear facilities, and over radioactive waste and spent fuel management; b) state surveillance over nuclear materials, their record-keeping and accountancy; c) state surveillance over the safeguarding of nuclear facilities and nuclear materials; d) state surveillance over selected materials, facilities and technologies used in the nuclear field, as well as dual-purpose materials and facilities; e) state surveillance over protection against ionizing radiation; f) coordination of the performance of the Radiation Monitoring Network over the Czech Republic and responsibility for international exchange of data on the radiological situation. The Act is reproduced in full, and the organizational structure of the Office is shown in a chart. (J.B.)

  11. Monovacancy paramagnetism in neutron-irradiated graphite probed by 13C NMR.

    Science.gov (United States)

    Zhang, Zhi Tao; Xu, C; Dmytriieva, Daryna; Molatta, Sebastian; Wosnitza, J; Wang, Y T; Helm, Manfred; Zhou, Shengqiang; Kuehne, Hannes

    2017-09-18

    We report on the magnetic properties of monovacancy defects in neutron-irradiated graphite, probed by $^{13}$C nuclear magnetic resonance spectroscopy. The bulk paramagnetism of the defect moments is revealed by the temperature dependence of the NMR frequency shift and spectral linewidth, both of which follow a Curie behavior, in agreement with measurements of the macroscopic magnetization. Compared to pristine graphite, the fluctuating hyperfine fields generated by the defect moments lead to an enhancement of the $^{13}$C nuclear spin-lattice relaxation rate $1/T_{1}$ by about two orders of magnitude. With an applied magnetic field of 7.1 T, the temperature dependence of $1/T_{1}$ below about 10 K can well be described by a thermally activated form, $1/T_{1}\\propto\\exp(-\\Delta/k_{B}T)$, yielding a singular Zeeman energy of ($0.41\\pm0.01$) meV, in excellent agreement with the sole presence of polarized, non-interacting defect moments. © 2017 IOP Publishing Ltd.

  12. Solid state {sup 13}C NMR study on the synthesis of graphite oxide from different graphitic precursors; Estudo atravéS de RMN de {sup 13}C no estado sólido sobre a síntese de oxido de grafite utilizando diferentes precursores grafíticos

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Mariana A.; Frasson, Carolina Maria R.; Costa, Tainara Luiza G.; Cipriano, Daniel F.; Schettino Junior, Miguel A.; Cunha, Alfredo G.; Freitas, Jair C.C., E-mail: marianaarpini@hotmail.com [Universidade Federal do Espírito Santo (UFES), Vitória, ES (Brazil). Lab. de Materiais Carbonosos e Cerâmicos

    2017-10-15

    The influence of the structural and microstructural characteristics of graphitic precursors on the production of graphite oxide (GO) is investigated in the present work. Six different graphitic precursors were used to produce GO following a modified Hummers method, namely: natural graphite, commercial lubricant graphite, milled graphite, graphite flakes, high-purity graphite and graphite recycled from Li-ion batteries. The products were characterized by X-ray diffraction (XRD), thermogravimetry, solid-state {sup 13}C nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM). {sup 13}C NMR spectra revealed the presence of epoxy, hydroxyl, carbonyl and lactol groups in the synthesized GOs. However, the oxidation degree of each product was found to be dependent on the average crystallite size (Lc) and particle size of the graphitic precursors, with the best GO samples being produced from the milled graphite and the graphite recycled from ion-Li batteries. These results were rationalized in terms of the structural and microstructural differences among the graphitic precursors, as revealed by the XRD patterns and SEM images, evidencing the importance of the correct choice of the precursor aiming the achievement of a well-developed structure for the GO product. (author)

  13. Synthesis of 1-13C-1-indanone and 2-13C-1,2,3,4-tetrahydroquinoline

    International Nuclear Information System (INIS)

    Pickering, R.E.; Wysocki, M.A.; Eisenbraun, E.J.

    1985-01-01

    The synthesis of 2- 13 C-1,2,3,4-tetrahydroquinoline (5) via 1- 13 C-3-phenylpropanoic acid (1), 1- 13 C-1-indanone (2), 1- 13 C-1-indanone hydrazone (3) and 2- 13 C-3,4-dihydro-2(1H)-quinolinone (4) proceeded in 78, 96, 95, 79, and 85% individual yields respectively for 1, 2, 3, 4, 5 and 61% overall yield of the latter from 1. (author)

  14. Experimental and theoretical investigation of scattering of alpha particles from 13C nuclei

    International Nuclear Information System (INIS)

    Burtebayev, N.; Burtebayeva, D.T.; Baktybayev, M.K.; Duisebayev, B.A.; Ogloblin, A.A.; Demyanova, A.S.; Sakuta, Sh.; Hamada, C.B.; Janseitov, D.M.; Nassurlla, M.; Artemov, S.V.

    2015-01-01

    13 C is a good example of a “normal” nucleus well described by the shell model. Its level scheme is reliably determined up to the excitation energies ~ 10 MeV (see e.g. [1]). However, some new approaches such as the hypothesis of the α-particle condensation suggest that cluster states with an enhanced radius can appear. The famous Hoyle state (0 2 + , E* = 7.65 MeV) in 12 C was considered as the most probable candidate for having such structure. It was also expected that the analogues of the Hoyle state would reveal themselves in some neighboring nuclei, e.g., the ½- (E*= 8.86MeV) state in 13 C. The analysis of the 13 C + α scattering data measured at E (α) = 388 MeV really demonstrated a considerable enhancement of the radius of this particular state. However, the method of extracting the radii used may not be quite adequate at high energies (≥ 100 MeV) when nuclei are too transparent. The existence in 13 C of some states with enhanced dimensions but of different structure was discussed as well. Thus, a neutron halo was identified in the first excited state 3.09 MeV (1/2 + ) by two independent and complementary methods. Consequently, new measurements especially at lower energies are highly desirable

  15. Comparison of soil organic carbon speciation using C NEXAFS and CPMAS 13C NMR spectroscopy.

    Science.gov (United States)

    Prietzel, Jörg; Müller, Svenja; Kögel-Knabner, Ingrid; Thieme, Jürgen; Jaye, Cherno; Fischer, Daniel

    2018-07-01

    We compared synchrotron-based C near-edge X-ray absorption fine structure (NEXAFS) and CPMAS 13 C nuclear magnetic resonance (NMR) spectroscopy with respect to their precision and accuracy to quantify different organic carbon (OC) species in defined mixtures of soil organic matter source compounds. We also used both methods to quantify different OC species in organic surface horizons of a Histic Leptosol as well as in mineral topsoil and subsoil horizons of two soils with different parent material, stage of pedogenesis, and OC content (Cambisol: 15-30 OC mgg -1 , Podzol: 0.9-7 OC mgg -1 ). CPMAS 13 C NMR spectroscopy was more accurate and precise (mean recovery of different C functional groups 96-103%) than C NEXAFS spectroscopy (mean recovery 92-113%). For organic surface and topsoil samples, NMR spectroscopy consistently yielded larger O-alkyl C percentages and smaller alkyl C percentages than C NEXAFS spectroscopy. For the Cambisol subsoil samples both methods performed well and showed similar C speciation results. NEXAFS spectroscopy yielded excellent spectra with a high signal-to-noise ratio also for OC-poor Podzol subsoil samples, whereas this was not the case for CPMAS 13 C NMR spectroscopy even after sample treatment with HF. Our results confirm the analytical power of CPMAS 13 C NMR spectroscopy for a reliable quantitative OC speciation in soils with >10mgOCg -1 . Moreover, they highlight the potential of synchrotron-based C NEXAFS spectroscopy as fast, non-invasive method to semi-quantify different C functional groups in soils with low C content (0.9-10mgg -1 ). Copyright © 2018 Elsevier B.V. All rights reserved.

  16. State shipment fees as a supplement to federal financial assistance under section 180(c) of the nuclear waste policy act

    International Nuclear Information System (INIS)

    Janairo, L.R.

    2009-01-01

    In Section 180(c) of the Nuclear Waste Policy Act (NWPA), Congress requires the Secretary of Energy to provide financial and technical assistance to states and tribes that will be affected by shipments of spent nuclear fuel and high-level radioactive waste (HLW) to a national repository or other NWPA-mandated facility. Although Section 180(c) assistance may be an important source of revenue for some states, two major limitations will reduce its effectiveness in preparing state and local personnel along shipping routes for their oversight and emergency response roles in connection with shipments to a national repository. First, Section 180(c) applies only to shipments to facilities mandated by the NWPA, therefore unless Congress amends the NWPA, the Secretary has no obligation to provide assistance to states and tribes that are affected by shipments to private facilities or to other federal storage locations. Second, the U.S. Department of Energy (DOE) has interpreted Section 180(c) assistance as solely intended 'for training', not for actually carrying out activities such as inspecting or escorting shipments. No mechanism or mandate currently exists for DOE to provide states with assistance in connection with operations - related activities. This paper looks at state shipment fees as a supplement to or a substitute for the federal financial assistance that is available through Section 180(c) specifically with regard to states. Using DOE' s data on projected shipment numbers, representative routes, and affected population, and following the department's proposed formula for allocating Section 180(c) assistance, the author examined the potential revenues states could reap through a standard fee as opposed to the NWPA-mandated assistance . The analysis shows that, while more states would likely derive greater benefit from Section 180(c) grants than they would from fees, the states with the highest projected shipment numbers would appear to gain by foregoing Section

  17. 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)

  18. State nuclear initiatives in the United States

    International Nuclear Information System (INIS)

    Strauss, P.L.; Stoiber, C.R.

    1977-01-01

    The paper deals with State nuclear initiatives regarding the role of nuclear power in the energy future of the United States. The question of whether and under what circumstances nuclear facilities should be used to generate electricity was put to the popular vote in several States in 1976. Some general principles of Federal-State relations are discussed with specific reference to nuclear regulations. The initiative mechanism itself is described as well as its legal form and background. The parallel developments in the State and Federal legislative consideration of nuclear issues is reviewed and the suggested reasons for the defeat of the proposals in the seven States concerned are discussed. Finally, the author draws some conclusions on the effects of the 1976 initiatives on future decision-making in the US on energy policy in general and nuclear power in particular. (NEA) [fr

  19. Carbon-13 composition of bulk dry wines by irm-EA/MS and irm-13C NMR: An indicator of vine water status

    Directory of Open Access Journals (Sweden)

    Guyon Francois

    2017-01-01

    Full Text Available Measurements performed on a set of 32 authentic wines (not submitted to any oenological treatment and their ethanol, recovered by distillation, show high correlation between δ13C of bulk wine and its ethanol. These measurements were performed by isotope ratio monitoring by mass spectrometry coupled to an elemental analyzer (irm-EA/MS. Then a series of wines produced by vines of which water status was assessed during the growing season with predawn leaf water potential measurements, was studied by irm-EA/MS. As expected δ13C is correlated to vine water status conditions, as a result of stomatal closure. The ethanol of these specific wines was also analyzed by isotope ratio monitoring and by nuclear magnetic resonance (irm-13C NMR to determine carbon-13 composition on the two specific sites of the ethanol skeleton. If these measurements confirm the correlation between 13C composition and vine growth conditions, the 13C stereospecific information does not make vine water status assessment more precise.

  20. The structure of teichoic acid from Bacillus subtilis var. niger WM as determined by 13C nuclear-magnetic-resonance spectroscopy

    International Nuclear Information System (INIS)

    De Boer, W.R.; Kruyssen, F.J.; Wouters, J.T.M.; Kruk, C.

    1976-01-01

    The walls of Bacillus subtilis var. niger WM, grown in a Mg 2+ -limited chemostat culture (carbon source glucose, dilution rate = 0.2 h -1 , 37 0 C, pH 7) contained 45% (w/w) teichoic acid, a polymer composed of glycerol, phosphate and glucose in the molar ratio 1.00 : 1.00 : 0.88. Alkaline hydrolysis of this teichoic acid yielded 1-O-β-glucosylglycerol phosphate (together with small amounts of glycerol phosphate), and 13 C nuclear magnetic resonance spectra of this hydrolysis product, and its derivative after alkaline phosphatase treatment, confirmed that the monomeric unit was 1-O-β-glucosylglycerol-3-phosphate. Assignment of the resonances in the spectrum of undegraded teichoic acid revealed that the polymer was a poly[(2,3)glycerol phosphate], glucosidically substituted on C-1 of glycerol with β-glucose. (orig.) [de

  1. Determination of urea 13C in urea 13C mixed powder by HPLC

    International Nuclear Information System (INIS)

    Zhong Jianguo; Song Tianqi

    2006-01-01

    A HPLC method is developed for determination of Urea 13 C in Urea 13 C Mixed Powder. A Alltech Econosphere NH2 column (250 mm x 4.6 mm, 5 μm)is used as stationary phrase, a mixture of V(acetonitrile): V(methanol): V(water) = 900 : 100: 10 is used as mobile phase and the flow rate is l mL·min -1 , UV detection wavelength is performed at 200 nm. The calibration curve shows good linearity in the range of 0.2-1.0 g·L -1 of Urea 13 C, y=2.548 x 10 6 x + 4.005 x 10 4 , r=0.9999, and the averaged recovery is 100.6%. The method is simple and accurate, and can be used for the quality control of Urea 13C Mixed Powder. (authors)

  2. 13C Kinetic isotopic effect of polymerization on monomers with multiple bond

    International Nuclear Information System (INIS)

    Berman, E.L.; Polyakov, V.B.; Makovetskij, K.L.; Golenko, T.G.; Galimov, Eh.M.; AN SSSR, Moscow. Inst. Organicheskoj Khimii; AN SSSR, Moscow. Inst. Geokhimii i Analiticheskoj Khimii)

    1988-01-01

    13 C kinetic isotopic effect (KIE) of anionic and radical polymerization and metathesis reaction of monomers with multiple bonds are studied and correlation between the found KIE values of polymerization and the structure of transition state is established. 13 C KIE of polymerization reactions are investigated using monomers with natural content of the isotope. Polymerization was carried out using high-vacuum equipment: radical polymerization of methyl acrylate (MA) and vinyl acetate in benzene solution under the effect of benzoyl peroxide (60 deg C); anionic polymerization of MA, initiated by potassium butyl cellosolvolate, was realized in mass at 25 deg C; cyclopentene metathesis reaction was conducted in benzene under the effect of initiating system WCl 6 - (C 3 H 5 ) 2 Si(CH 3 ) 2 at -30 deg C; phenylacetylene polymers were prepared by polymerization in benzene solution at 20 deg C under the effect of WCl 6 . It is ascertained that 13 C KIE of radical and anionic polymerization of olefins and cycloolefin metathesis constitutes 2.0 -2.4%. Polymerization of compound with ternary bond is accompanied by a lower value of 13 C KIE (<1%), which is explained by double bond of reacting bond in transition state

  3. Unambiguous assigning of the signals of the nuclear magnetic resonance spectra of 1 H and 13 C of monoterpenes using computational methods

    International Nuclear Information System (INIS)

    Cortes, F.; Cuevas, G.; Tenorio, J.; Rochin, A.L.

    2000-01-01

    Ab initio calculations, within the frame of Density Functional Theory were carried out on camphene and α-pinene. The 1 H and 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 1 H nuclei and qualitatively in the case of 13 C nuclei, but also allow assigning unambiguously the signal on these spectra. (Author)

  4. 13C/14C dual isotope breath test measurement of gastric emptying in normal subjects and patients

    International Nuclear Information System (INIS)

    Chew, G.; Bartholomeusz, F.D.L.; Bellon, M.; Chatterton, B.E.

    2000-01-01

    Full text: A more flexible alternative to dual isotope scintigraphy for gastric emptying involves measuring breath C0 2 after administration of absorbable tracers. Method: six patients were given 100g hamburger labelled with 25 MBq 99 Tc m sulphur colloid and 74 KBq 14 C octanoic acid, and 150 ml 10% glucose drink labelled with 8 MBq 67 Ga citrate and ISO mg 13 C acetate and seven normals with 14 C and 13 C labels only. Breath was collected at baseline and then regularly for four hours. The 14 CO 2 and 13 CO 2 activity was measured with liquid scintillation counting and mass spectroscopy. The times to maximum 14 CO 2 , and 13 CO 2 , T max, were determined. Results: Comparison was made between 14 CO 2 T max with scintigraphic retention of 99 Tc m at 100 minutes (SR100m) and 13 CO 2 T max with the scintigraphic half-clearance time of 67 Ga (scint T1/2). In conclusion 14 CO 2 T max and 13 CO 2 T max correlate significantly with SR100m and scint T1/2 respectively. The normal threshold is between 165 and 180 minutes for 14 Co 2 T max; probably > 40 minutes for 13 CO 2 T max but overlap exists between normal and abnormal results in this small preliminary study. Recruitment is to continue to better define normal ranges. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  5. Nuclear Landau-Zener phenomena and the fusion cross sections in the system 13C + 16O → 12C + 17O

    International Nuclear Information System (INIS)

    Imanishi, B.; Oertzen, W. von.

    1990-07-01

    Reaction mechanism of the system 13 C+ 16 O- 12 C+ 17 O is investigated with the use of the nucleon molecular-orbital model in the framework of the orthogonalized coupled-reaction-channel (OCRC) theory. The adiabatic potentials obtained are quite different from the diagonal potentials of the original OCRC basis. The Landau-Zener radial coupling explains the backward enhancement of measured differential cross sections of the transfer reaction 13 C( 16 O, 17 O) 12 C. In the OCRC calculation the fusion cross sections of the channel 13 C+ 16 O is enhanced at low bombarding energies, in agreement with the experimental data. (author)

  6. The Fragmentation of Heavy Nuclei by 13.8 GeV/c Protons as a Contribution to the Study of the Interaction Mechanism and Nuclear Structure

    International Nuclear Information System (INIS)

    Gil Perez, D.

    1967-01-01

    We present he re an global study of the interaction between high- energy particles and heavy nuclei, an interaction which holds obvious interest in relation to the problems of nuclear fragmentation and which, up lo now has only been studied piecemeal. We have used three stacks of photographic emulsions which were irradiated by 13.8 GeV/c protons, 17 GeV/c negative pions and 24 GeV/c protons. All three irradiations took place in a 180 K.G. magnetic field using CERN beams. (Author) 20 refs

  7. 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.

  8. Syntheses of DL-[2-13C]leucine and its use in the preparation of [3-DL-[2-13C]leucine]oxytocin and [8-DL-[2-13C]leucine]oxytocin

    International Nuclear Information System (INIS)

    Viswanatha, V.; Larsen, B.; Hruby, V.J.

    1979-01-01

    DL-[2- 13 C]Leucine was prepared by condensing the sodium salt of ethyl acetamido-[2- 13 C]cyanoacetate with isobutylbromide in hexamethylphosphoroustriamide followed by acid hydrolysis. N-BOC-DL-[2- 13 C]Leucine was prepared and incorporated into [8-DL-[2- 13 C]leucine]oxytocin by total synthesis. The 13 C-labeled hormone derivative [8-[2- 13 C]leucine]oxytocin was separated from its 8-position diastereoisomer by partition chromatography. The specifically 13 C-labeled peptide hormone diastereoisomeric analog [3-DL-[2- 13 C]leucine]oxytocin also was prepared by solid phase peptide synthesis. No suitable solvent system for partition chromatography separation of the latter diastereoisomeric peptide mixture could be found. However an excellent preparative separation of the diastereoisomers could be obtained by reverse phase high pressure liquid chromatography on a partisil 10 M9 ODS column using the solvent system 0.05 M ammonium acetate (pH 4.0), acetonitrile (81:19, v/v) to give pure [3-[2- 13 C]leucine]oxytocin and [3-D-[2- 13 C]leucine]oxytocin. An excellent separation of [8-[2- 13 C]leucine]oxytocin and the corresponding delata-D-leucine diastereoisomer derivative could also be accomplished by high pressure liquid chromatography. (author)

  9. In vivo dynamic turnover of cerebral 13C isotopomers from [U- 13C]glucose

    Science.gov (United States)

    Xu, Su; Shen, Jun

    2006-10-01

    An INEPT-based 13C MRS method and a cost-effective and widely available 11.7 Tesla 89-mm bore vertical magnet were used to detect dynamic 13C isotopomer turnover from intravenously infused [U- 13C]glucose in a 211 μL voxel located in the adult rat brain. The INEPT-based 1H → 13C polarization transfer method is mostly adiabatic and therefore minimizes signal loss due to B 1 inhomogeneity of the surface coils used. High quality and reproducible data were acquired as a result of combined use of outer volume suppression, ISIS, and the single-shot three-dimensional localization scheme built in the INEPT pulse sequence. Isotopomer patterns of both glutamate C4 at 34.00 ppm and glutamine C4 at 31.38 ppm are dominated first by a doublet originated from labeling at C4 and C5 but not at C3 (with 1JC4C5 = 51 Hz) and then by a quartet originated from labeling at C3, C4, and C5 (with 1JC3C4 = 35 Hz). A lag in the transition of glutamine C4 pattern from doublet-dominance to quartet dominance as compared to glutamate C4 was observed, which provides an independent verification of the precursor-product relationship between neuronal glutamate and glial glutamine and a significant intercompartmental cerebral glutamate-glutamine cycle between neurons and glial cells.

  10. Differential cross section measurement of radiative capture of protons by nuclei 13C

    International Nuclear Information System (INIS)

    Baktibayev, M.K.; Burminskii, V.P.; Burtebayev, N.; Dzazairov-Kakhramanov, V.; Kadyrzhanov, K.K.; Sagindykov, Sh.Sh.; Zarifov, R.A.; Zazulin, D.M.

    2004-01-01

    Full text: The reaction 13 C(p,γ ) 14 N is the important one for the astrophysics, not only for nuclear synthesis of CNO elements, but and for nuclear synthesis of elements participating in subsequent combustion of helium [1]. The predominant yield of the reaction occurs at protons energies of less than 1 MeV. However, the clearness of the capture mechanism in this energy region is made difficult because of the superposition of the contribution of the low - energetical part of the resonance 1320 keV onto the cross section. Last experimental data for more wide energy region, informed in the work [1], and results of previous works, mentioned in that work, give reason for further continuation of the study of the reaction 13 C(p,γ ) 14 N. Measured data of the work [1] in the region of E ρ = (320 † 900) keV at the angles of 0 o and 90 o are obviously insufficient. In the present work measurements of differential cross sections of the reaction were carried out at protons energies E p = 991, 558 and 365 keV, the accuracy is not worse then 10%. There was studied the most (from the astrophysical point of view) important process of protons capture by 13 C nuclei onto the ground state of the 14 N nucleus. The 13 C (99%) targets, used in the experiment, were sprayed onto copper base. The target thickness was determined by incident protons energy losses in the target. The energy losses were clearly reflected in the corresponding spreading of transitions of radiation capture. The statement about the gamma-lines spreading is valid in this case, because energy losses in the target are here significantly more, than the energetical resolution of the detector. The peak width of the radiation capture gamma-line at half-height corresponds to energy losses of incident protons in the target. From the Table of brake values for protons in carbon [2] there was determined that the thickness of the target was 140 ± 5% μg/cm 2 . The upper part of gamma-lines in the spectrum repeats the

  11. Differential effects of safflower oil versus fish oil feeding on insulin-stimulated glycogen synthesis, glycolysis, and pyruvate dehydrogenase flux in skeletal muscle: a 13C nuclear magnetic resonance study.

    Science.gov (United States)

    Jucker, B M; Cline, G W; Barucci, N; Shulman, G I

    1999-01-01

    To examine the effects of safflower oil versus fish oil feeding on in vivo intramuscular glucose metabolism and relative pyruvate dehydrogenase (PDH) versus tricarboxylic acid (TCA) cycle flux, rats were pair-fed on diets consisting of 1) 59% safflower oil, 2) 59% menhaden fish oil, or 3) 59% carbohydrate (control) in calories. Rates of glycolysis and glycogen synthesis were assessed by monitoring [1-(13)C]glucose label incorporation into [1-(13)C]glycogen, [3-(13)C]lactate, and [3-(13)C]alanine in the hindlimb of awake rats via 13C nuclear magnetic resonance (NMR) spectroscopy during a euglycemic (approximately 6 mmol/l) hyperinsulinemic (approximately 180 microU/ml) clamp. A steady-state isotopic analysis of lactate, alanine, and glutamate was used to determine the relative PDH versus TCA cycle flux present in muscle under these conditions. The safflower oil-fed rats were insulin resistant compared with control and fish oil-fed rats, as reflected by a markedly reduced glucose infusion rate (Ginf) during the clamp (21.4 +/- 2.3 vs. 31.6 +/- 2.8 and 31.7 +/- 1.9 mg x kg(-1) x min(-1) in safflower oil versus control and fish oil groups, respectively, P safflower oil group was associated with a lower rate of glycolysis (21.7 +/- 2.2 nmol x g(-1) x min(-1)) versus control (62.1 +/- 10.3 nmol x g(-1) x min(-1), P safflower oil, fish oil, and control, respectively) was detected. The intramuscular triglyceride (TG) content was increased in the safflower oil group (7.3 +/- 0.8 micromol/g) compared with the control group (5.2 +/- 0.8 micromol/g, P safflower oil (43 +/- 8%) versus the control (73 +/- 8%, P safflower oil feeding was a consequence of reduced glycolytic flux associated with an increase in relative free fatty acid/ketone oxidation versus TCA cycle flux, whereas fish oil feeding did not alter glucose metabolism and may in part be protective of insulin-stimulated glucose disposal by limiting intramuscular TG deposition.

  12. 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

  13. {sup 13}C dynamic nuclear polarization for measuring metabolic flux in endothelial progenitor cells

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Nathalie; Laustsen, Christoffer; Bertelsen, Lotte Bonde, E-mail: Lotte@clin.au.dk

    2016-11-15

    Endothelial progenitor cells (EPCs) represent a heterogeneous cell population that is believed to be involved in vasculogenesis. With the purpose of enhancing endothelial repair, EPCs could have a potential for future cell therapies. Due to the low amount of EPCs in the peripheral circulating blood, in vitro expansion is needed before administration to recipients and the effects of in vitro culturing is still an under-evaluated field with little knowledge of how the cells change over time in culture. The aim of this study was to use hyperpolarised carbon-13 magnetic resonance spectroscopy to profile important metabolic pathways in a population of progenitor cells and to show that cell culturing in 3D scaffolds seem to block the metabolic processes that leads to cell senescence. The metabolic breakdown of hyperpolarized [1-{sup 13}C]pyruvate was followed after injection of the substrate to a bioreactor system with EPCs either adhered to 3D printed scaffolds or kept in cell suspension. The pyruvate-to-lactate conversion was elevated in suspension of EPCs compared to the EPCs adhered to scaffolds. Furthermore in the setup with EPCs in suspension, an increase in lactate production was seen over time indicating that the older the cultures of EPCs was before using the cells for cell suspension experiments, the more lactate they produce, compared to a constant lactate level in the cells adhered to scaffolds. It could therefore be stated that cells grown first in 2D culture and subsequent prepared for cell suspension show a metabolism with higher lactate production consistent with cells senescence processes compared to cells grown first at 2D culture and subsequent in the 3D printed scaffolds, where metabolism shows no sign of metabolic shifting during the monitored period. - Highlights: • Hyperpolarized 13C MRS detects EPCs metabolic changes associated with ageing and cultivating conditions. • Increased lactate production in EPC’s correlates positively with aging.

  14. Astrophysical S factor for 13C(p,γ)14N and asymptotic normalization coefficients

    International Nuclear Information System (INIS)

    Mukhamedzhanov, A.M.; Azhari, A.; Gagliardi, C.A.; Sattarov, A.; Tang, X.; Trache, L.; Tribble, R.E.; Burjan, V.; Kroha, V.

    2002-01-01

    We reanalyze the 13 C(p,γ) 14 N radiative capture reaction within the R-matrix approach. The low-energy astrophysical S factor has important contributions from both resonant and onresonant captures. The normalization of the nonresonant component of the transition to a particular 14 N bound state is expressed in terms of the asymptotic normalization coefficient (ANC). In the analysis we use the experimental ANC's inferred from the 13 C( 14 N, 13 C) 14 N and 13 C( 3 He,d) 14 N reactions. The fits of the calculated S factors to the experimental data are sensitive to the ANC values and are used to test the extracted ANC's. We find that for transitions to all the states in 14 N, except the third excited state, the ANC's determined from the transfer reactions provide the best fit. The astrophysical factor we obtain, S(0)=7.7±1.1 keV b, is in excellent agreement with previous results

  15. Synthesis and evaluation of nitroxide-based oligoradicals for low-temperature dynamic nuclear polarization in solid state NMR

    Science.gov (United States)

    Yau, Wai-Ming; Thurber, Kent R.; Tycko, Robert

    2014-07-01

    We describe the synthesis of new nitroxide-based biradical, triradical, and tetraradical compounds and the evaluation of their performance as paramagnetic dopants in dynamic nuclear polarization (DNP) experiments in solid state nuclear magnetic resonance (NMR) spectroscopy with magic-angle spinning (MAS). Under our experimental conditions, which include temperatures in the 25-30 K range, a 9.4 T magnetic field, MAS frequencies of 6.2-6.8 kHz, and microwave irradiation at 264.0 GHz from a 800 mW extended interaction oscillator source, the most effective compounds are triradicals that are related to the previously-described compound DOTOPA-TEMPO (see Thurber et al., 2010), but have improved solubility in glycerol/water solvent near neutral pH. Using these compounds at 30 mM total nitroxide concentration, we observe DNP enhancement factors of 92-128 for cross-polarized 13C NMR signals from 15N,13C-labeled melittin in partially protonated glycerol/water, and build-up times of 2.6-3.8 s for 1H spin polarizations. Net sensitivity enhancements with biradical and tetraradical dopants, taking into account absolute 13C NMR signal amplitudes and build-up times, are approximately 2-4 times lower than with the best triradicals.

  16. Comparison of Accuracy Between 13C- and 14C-Urea Breath Testing: Is an Indeterminate-Results Category Still Needed?

    Science.gov (United States)

    Charest, Mathieu; Bélair, Marc-André

    2017-06-01

    Helicobacter pylori infection is the leading cause of peptic ulcer disease. The purpose of this study was, first, to assess the difference in the distribution of negative versus positive results between the older 14 C-urea breath test and the newer 13 C-urea breath test and, second, to determine whether use of an indeterminate-results category is still meaningful and what type of results should trigger repeated testing. Methods: A retrospective survey was performed of all consecutive patients referred to our service for urea breath testing. We analyzed 562 patients who had undergone testing with 14 C-urea and 454 patients who had undergone testing with 13 C-urea. Results: In comparison with the wide distribution of negative 14 C results, negative 13 C results were distributed farther from the cutoff and were grouped more tightly around the mean negative value. Distribution analysis of the negative results for 13 C testing, compared with those for 14 C testing, revealed a statistically significant difference between the two. Within the 13 C group, only 1 patient could have been classified as having indeterminate results using the same indeterminate zone as was used for the 14 C group. This is significantly less frequent than what was found for the 14 C group. Discussion: Borderline-negative results do occur with 13 C-urea breath testing, although less frequently than with 14 C-urea breath testing, and we will be carefully monitoring differences falling between 3.0 and 3.5 %Δ. 13 C-urea breath testing is safe and simple for the patient and, in most cases, provides clearer positive or negative results for the clinician. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

  17. Proton detected 13C imaging. Implementation and development

    International Nuclear Information System (INIS)

    Hudson, A.M.J.

    1999-08-01

    The work described in this thesis has been undertaken by the author, except where indicated by reference, within the Magnetic Resonance Centre at the University of Nottingham during the period from October 1996 to March 1999. This thesis documents the implementation and development of an imaging technique used to generate proton detected nuclear magnetic resonance images, representing the density of carbon-13 nuclear spins. The technique uses rotating frame, liquid state coherent polarisation transfer to generate carbon-13 edited proton signal. The dual resonant radio frequency (RF) coils used to create the homogeneous RF fields, intrinsic to the polarisation transfer are described, along with a consideration of their properties. Single resonant structures are also investigated, and a microscopy coil suitable for side access imaging studies is presented. By the use of field plotting methods, the main magnet field homogeneity was optimised, and the resonator RF fields were characterised. This provided the information for a theoretical evaluation of the efficacy of this implementation of the cyclic cross polarisation sequence, which was confirmed experimentally. Applications of the cyclic cross polarisation imaging scheme are presented, along with a novel variant of the sequence, used for mapping the RF field within samples with a low magnetogyric ratio. (author)

  18. Multi site Kinetic Modeling of 13C Metabolic MR Using [1-13C]Pyruvate

    International Nuclear Information System (INIS)

    Damian, P.A.G.; Sperl, J.I.; Janich, M.A.; Wiesinger, F.; Schulte, R.F.; Menzel, M.I.; Damian, P.A.G.; Damian, P.A.G.; Haase, A.; Janich, M.A.; Schwaiger, M.; Janich, M.A.; Khegai, O.; Glaser, S.J.

    2014-01-01

    Hyperpolarized 13 C imaging allows real-time in vivo measurements of metabolite levels. Quantification of metabolite conversion between [1- 13 C]pyruvate and downstream metabolites [1- 13 C]alanine, [1- 13 C]lactate, and [ 13 C] 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 multi site, dynamic model involving possible biochemical pathways present in MR spectroscopy. Kinetic modeling parameters were determined by fitting the multi site 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 multi site 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

  19. Nuclear Data Activities at I.I.T. Roorkee - Period 2011-13

    Energy Technology Data Exchange (ETDEWEB)

    Jain, A. K. [Indian Institute of Technology Roorkee, Roorkee 247667 (India)

    2013-08-15

    Isomers has been prepared (a horizontal evaluation). Details of this study are as follows: We have prepared an Atlas of all the known nuclear isomers for all the neutron and proton numbers, to highlight the extent of information in this promising and highly interesting field. The total number of nuclear isomers for the complete mass region has been found to be about 2252 including 507 nuclei having only one known isomer and 559 nuclei having isomers between 2 and 5. Nuclear isomers have been found all over the nuclear chart, the largest number being near the magic numbers and gap. It was interesting to find {sup 180}Ta to have the largest number (13) of isomeric states. {sup 179,177}Ta, {sup 152}Eu, {sup 214}Rn were found to have 10 isomeric states each. A theoretical estimation of the half-lives of transitions was made using the Weisskopff single particle estimates which were then compared to the experimental half-lives. The number of isomers is found to be highest in the range 1 ns-100 ns. The number falls gradually with the increase in half-life of the isomeric states up to 0.1s and then a small rise being observed at 10s-10{sup 3}s. The detailed results and findings have been presented in the conferences listed below. (1) Atlas of Nuclear Isomers and their Systematics, A.K. Jain, Talk delivered at Argonne National Lab, USA during a visit in August 2012. (2) Atlas of Nuclear Isomers and Spin Systematics, A.K. Jain, Invited talk in the BRNS workshop on Evaluation of Nuclear Structure and Decay Data, November 26-29, 2012, VECC, Kolkata. We have studied/developed a global systematics of the spins (total angular momentum) of nuclear isomeric states for nuclei in the whole mass region from A=1 to 240. Systematics of spins have been made region wise for a) Z(28-50) and N(28-50), b) Z(50-82) and N(50-82), and c) Z(50-82) and N(82-126). We observe that nuclear isomers having half-integer spins are more in number as compared to nuclei having integral spins for spins less than 6

  20. Electronic structure and physical properties of 13C carbon composite

    OpenAIRE

    Zhmurikov, Evgenij

    2015-01-01

    This review is devoted to the application of graphite and graphite composites in science and technology. Structure and electrical properties, as so technological aspects of producing of high-strength artificial graphite and dynamics of its destruction are considered. These type of graphite are traditionally used in the nuclear industry. Author was focused on the properties of graphite composites based on carbon isotope 13C. Generally, the review relies on the original results and concentrates...

  1. Synthesis of [21-13C]-cholesterol

    International Nuclear Information System (INIS)

    Caballero, G.M.; Gros, E.G.

    1994-01-01

    The synthesis of [21- 13 C]-cholesterol from 3β-O-(t-butyldimethylsilyl)-17β-cyano-androst-5-ene is described. Labelled carbon-atom was introduced by Grignard reaction of nitrile derivative with [ 13 C]-methylmagnesium iodide. Location of label was confirmed by 13 C-NMR spectroscopy. (author)

  2. Determinations of the 12C/13C Ratio for the Secondary Stars of AE Aquarii, SS Cygni, and RU Pegasi

    Science.gov (United States)

    Harrison, Thomas E.; Marra, Rachel E.

    2017-07-01

    We present new moderate-resolution near-infrared spectroscopy of three CVs obtained using GNIRS on Gemini-North. These spectra covered three 13CO bandheads found in the K-band, allowing us to derive the isotopic abundance ratios for carbon. We find small 12C/13C ratios for all three donor stars. In addition, these three objects show carbon deficits, with AE Aqr being the most extreme ([C/Fe] = -1.4). This result confirms the conjecture that the donor stars in some long-period CVs have undergone considerable nuclear evolution prior to becoming semi-contact binaries. In addition to the results for carbon, we find that the abundance of sodium is enhanced in these three objects, and the secondary stars in both RU Peg and SS Cyg suffer magnesium deficits. Explaining such anomalies appears to require higher mass progenitors than commonly assumed for the donor stars of CVs. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), and Ministério da Ciência, Tecnologia e Inovação (Brazil).

  3. IRMS detection of testosterone manipulated with 13C labeled standards in human urine by removing the labeled 13C

    International Nuclear Information System (INIS)

    Wang, Jingzhu; Yang, Rui; Yang, Wenning; Liu, Xin; Xing, Yanyi; Xu, Youxuan

    2014-01-01

    Highlights: • 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 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 13 C value). However, 13 C labeled standards can be used to control the δ 13 C value and produce manipulated T which cannot be detected by the current method. A method was explored to remove the 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 13 C values between Andro and ANAD (Δδ 13 C Andro–ANAD , ‰) would change significantly in case manipulated T is abused. Twenty-one volunteers administered T manipulated with different 13 C labeled standards. The collected urine samples were analyzed with the established method, and the maximum value of Δδ 13 C Andro–ANAD post ingestion ranged from 3.0‰ to 8.8‰. Based on the population reference, the cut-off value of Δδ 13 C Andro–ANAD for positive result was suggested as 1.2‰. The developed method could be used to detect T manipulated with 3- 13 C labeled standards

  4. NMR study of the 1-13C glucose colon bacterial metabolism

    International Nuclear Information System (INIS)

    Briet, F.; Flourie, B.; Pochart, P.; Rambaud, J.C.; Desjeux, J.F.; Dallery, L.; Grivet, J.P.

    1994-01-01

    The aim of the study is to examine in-vitro and by nuclear magnetic resonance the biological pathways for the fermentation of the 1- 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

  5. Fast neutron detection using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Vilela, E.C.

    1990-01-01

    CR-39 and Makrofol-E solid state nuclear track detectors were studied aiming their application to fast neutron detection. Optimum etching conditions of those two kinds of materials were determined the followings - the Makrofol-E detector is electrochemically etched in a PEW solution (15% KOH, 40% ethilic alcohol and 45% water) for 2 h., with an applied electric field strength of 30 kV/cm (r/m/s/) and frequency of 2 kHz, at room temperature; - the CR-39 detector is chemically pre-etched during 1 h in a 20% (w/v) NaOH solution at 70 sup(0)C, followed by 13 h electrochemical etch using the same solution at room temperature and an electric field strength of 30 kV/cm (r.m.s.) and frequency of 2 kHz.(E.G.)

  6. Acetylation of spermidine and methylglyoxal bis(guanylhydrazone) in baby-hamster kidney cells (BHK-21/C13).

    Science.gov (United States)

    Wallace, H M; Nuttall, M E; Robinson, F C

    1988-01-01

    Treatment of BHK-21/C13 cells with methylglyoxal bis(guanylhydrazone) (MGBG) induced the cytosolic form of spermidine N1-acetyltransferase. It stabilized the enzyme against proteolytic degradation, but the drug did not affect the enzyme activity in vitro. MGBG was itself acetylated by BHK-21/C13 cells, but at only one-tenth the rate at which spermidine was acetylated. Acetylation occurred almost exclusively in the nuclear fraction. The product was identified as N-acetyl-MGBG by h.p.l.c., by using [3H]acetyl-CoA and [14C]MGBG as co-substrates. The results suggest that the acetylation of MGBG by BHK-21/C13 cells occurs by a different acetyltransferase enzyme from that which acetylates spermidine. PMID:3421945

  7. Radiation oxidation of polypropylene: A solid-state 13C NMR study using selective isotopic labeling

    International Nuclear Information System (INIS)

    Mowery, Daniel M.; Assink, Roger A.; Derzon, Dora K.; Klamo, Sara B.; Bernstein, Robert; Clough, Roger L.

    2007-01-01

    Polypropylene samples, in which the three different carbon atoms along the chain were selectively labeled with carbon-13, were subjected to radiation under inert and air atmospheres, and to post-irradiation exposure in air at various temperatures. By using solid-state 13 C NMR measurements at room temperature, we have been able to identify and quantify the oxidation products. The isotopic labeling provides insight into chemical reaction mechanisms, since oxidation products can be traced back to their positions of origin on the macromolecule. The major products include peroxides and alcohols, both formed at tertiary carbon sites along the chain. Other products include methyl ketones, acids, esters, peresters, and hemiketals formed from reaction at the tertiary carbon, together with in-chain ketones and esters from reaction at the secondary chain carbon. No evidence is found of products arising from reactions at the methyl side chain. Significant temperature-dependent differences are apparent; for example much higher yields of chain-end methyl ketones, which are the indicator product of chain scission, are generated for both elevated temperature irradiation and for post-irradiation treatment at elevated temperatures. Time-dependent plots of yields of the various oxidation products have been obtained under a wide range of conditions, including the post-irradiation oxidation of a sample at room temperature in air that has been monitored for 2 years. Radiation-oxidation products of polypropylene are contrasted to products measured for 13 C-labeled polyethylene in an earlier investigation: the peroxides formed in irradiated polypropylene are remarkably longer lived, the non-peroxidic products are significantly different, and the overall ratios of oxidation products in polypropylene change relatively little as a function of the extent of oxidation

  8. Analysis of 14C and 13C in teeth provides precise birth dating and clues to geographical origin.

    Science.gov (United States)

    Alkass, K; Buchholz, B A; Druid, H; Spalding, K L

    2011-06-15

    The identification of human bodies in situations when there are no clues as to the person's identity from circumstantial data, poses a difficult problem to the investigators. The determination of age and sex of the body can be crucial in order to limit the search to individuals that are a possible match. We analyzed the proportion of bomb pulse derived carbon-14 ((14)C) incorporated in the enamel of teeth from individuals from different geographical locations. The 'bomb pulse' refers to a significant increase in (14)C levels in the atmosphere caused by above ground test detonations of nuclear weapons during the cold war (1955-1963). By comparing (14)C levels in enamel with (14)C atmospheric levels systematically recorded over time, high precision birth dating of modern biological material is possible. Above ground nuclear bomb testing was largely restricted to a couple of locations in the northern hemisphere, producing differences in atmospheric (14)C levels at various geographical regions, particularly in the early phase. Therefore, we examined the precision of (14)C birth dating of enamel as a function of time of formation and geographical location. We also investigated the use of the stable isotope (13)C as an indicator of geographical origin of an individual. Dental enamel was isolated from 95 teeth extracted from 84 individuals to study the precision of the (14)C method along the bomb spike. For teeth formed before 1955 (N=17), all but one tooth showed negative Δ(14)C values. Analysis of enamel from teeth formed during the rising part of the bomb-spike (1955-1963, N=12) and after the peak (>1963, N=66) resulted in an average absolute date of birth estimation error of 1.9±1.4 and 1.3±1.0 years, respectively. Geographical location of an individual had no adverse effect on the precision of year of birth estimation using radiocarbon dating. In 46 teeth, measurement of (13)C was also performed. Scandinavian teeth showed a substantially greater depression in

  9. 13C NMR and relaxation studies of the nanomagnet Mn12-acetate

    Science.gov (United States)

    Achey, Randall M.; Kuhns, Philip L.; Reyes, Arneil P.; Moulton, William G.; Dalal, Naresh S.

    2001-08-01

    The nanomagnet [Mn12O12(CH3COO)16(H2O)4].2CH3COOH.4H2O, also known as Mn12, has been synthesized with 13C labeling at the CH3 groups, and investigated by 13C NMR at fields up to 23 T. Using oriented samples, it is possible to resolve four distinct 13C peaks at room temperature, located on both sides of the unshifted Larmor frequency. These peaks were assigned to the four hyperfine-shifted, magnetically inequivalent sets of 13CH3 groups in the Mn12 lattice, based on a comparison with the crystal structure and point-dipole and spin-density calculations. These results establish that the unpaired electron spin density of the S=10 system in this cluster extends over the entire molecular framework, not just the core. These results are discussed in relationship to inelastic neutron scattering measurements. The temperature and field dependence of the 13C nuclear-spin-lattice-relaxation time T1 on the least shifted peak was measured. A single weakly field-dependent minimum at about 60 K is observed in the temperature dependence of the measured T1. The relaxation mechanism responsible for the T1 minimum is ascribed mainly to hindered rotation of the methyl group of the acetate ligand at higher temperature, and to electronic spin fluctuations at lower temperature.

  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 Hofmann; Chrestensen, Inge Byg; 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...... hydrate more readily than the galactan side chains and suggests that the overall hydration properties can be controlled by modifying the ratio of these side chains. Enzymatic modification of native (NA) RG-I provided samples with reduced content of arabinan (sample DA), galactan (sample DG), or both side...... chains (sample DB). Results of these samples suggested that hydration properties were determined by the length and character of the side chains. NA and DA exhibited similar hydration characteristics, whereas DG and DB were difficult to hydrate because of the less hydrophilic properties of the rhamnose...

  11. IRMS detection of testosterone manipulated with 13C labeled standards in human urine by removing the labeled 13C.

    Science.gov (United States)

    Wang, Jingzhu; Yang, Rui; Yang, Wenning; Liu, Xin; Xing, Yanyi; Xu, Youxuan

    2014-12-10

    Isotope ratio mass spectrometry (IRMS) is applied to confirm testosterone (T) abuse by determining the carbon isotope ratios (δ(13)C value). However, (13)C labeled standards can be used to control the δ(13)C value and produce manipulated T which cannot be detected by the current method. A method was explored to remove the (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(13)C values between Andro and ANAD (Δδ(13)CAndro-ANAD, ‰) would change significantly in case manipulated T is abused. Twenty-one volunteers administered T manipulated with different (13)C labeled standards. The collected urine samples were analyzed with the established method, and the maximum value of Δδ(13)CAndro-ANAD post ingestion ranged from 3.0‰ to 8.8‰. Based on the population reference, the cut-off value of Δδ(13)CAndro-ANAD for positive result was suggested as 1.2‰. The developed method could be used to detect T manipulated with 3-(13)C labeled standards. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. The /sup 13/C-/sup 13/C spin-spin coupling constants and the conformational equilibrium of alkyl phenyl sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Krividin, L.B.; Kalabin, G.A.

    1985-08-10

    The authors measure the direct geminal and vicinal spinspin coupling constants between the C-13 nuclei of the phenyl group in the series of alkyl phenyl sulfides C/sub 6/H/sub 5/SR. It was shown that the variation in most of the discussed constants is determined by the ratio of the planar and orthogonal conformers. Linear relationships were obtained between the C-13-C-13 constants and the fractions of the planar conformer. The C-13-C-13 spin-spin coupling constants in the planar and orthogonal conformers of the compounds were calculated by means of empirical relationships.

  13. Structural properties of carbon nanotubes derived from 13C NMR

    KAUST Repository

    Abou-Hamad, E.; Babaa, M.-R.; Bouhrara, M.; Kim, Y.; Saih, Y.; Dennler, S.; Mauri, F.; Basset, Jean-Marie; Goze-Bac, C.; Wå gberg, T.

    2011-01-01

    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

  14. Characterization of methacetin-methoxy-"1"3C

    International Nuclear Information System (INIS)

    Lu Weijing; Lu Hao; Yang Weicheng; Liu Weixia; Li Shuai; Xu Zhongjie; Guan Liang; Zhu Chengmo; Chen Suyun; Jiang Lei

    2010-01-01

    Methacetin-methoxy-"1"3C was synthesized by using methanol-"1"3C with a novel method, and the characterization of it was performed using HPLC, LC-MS and "1HMNR. The results indicated that the synthetic was right. And the yield of methacetin-methoxy-"1"3C was 70.0% with 99% "1"3C abundance and 99.8% purity. Compared with the classical method, there was more benefit. The methacetin "1"3C-breath test was performed with the synthetic on the live mice, which showed a precise reflection of alteration of liver function in liver injury and functional recovery. (authors)

  15. 13C/12C ratios in human urine concrementes

    International Nuclear Information System (INIS)

    Hoefs, J.; Armbruster, T.

    1978-01-01

    Oxalate, uric acid, and phosphate stones have been analyzed for their carbon isotope composition. The oxalate stones show delta 13 C values between -17.0 and -19.5 pro mille, the uric acid stones between -14.9 and -19.4 pro mille, and the phosphate stones between -13.0 and -23.9 pro mille. It is proposed that endogenic rather than exogenic sources are responsible for the 13 C/ 12 C ratios of the stones. The isotopic composition of the phosphate stones seems to be influenced primarily by bacterial activity. (orig.) [de

  16. Determination of the percentage of quitine desacetilation reaction by solid state carbon-13 NMR

    International Nuclear Information System (INIS)

    Ferracin, Ricardo J.; Cass, Quezia B.; Bassi, Ana L.

    1997-01-01

    Quitine is a bi-polymer largely found in invertebrates. As most compounds of this class are insoluble in common organic solvents, the des-acetylation percentile was obtained by carbon-13 solid state nuclear magnetic resonance. The methodology is presented. Results are presented

  17. Stereoselective synthesis of L-[4-13C]carnitine

    International Nuclear Information System (INIS)

    Unkefer, C.J.; Ehler, D.S.

    1991-01-01

    The stereoselective synthesis of L-[4- 13 C]carnitine was achieved in 5 steps. The label was introduced from K 13 CN into an easily separated diastereomeric pair of 3-deoxy-D-[1- 13 C]aldohexoses. Reductive amination of the labeled aldohexose yielded the corresponding D-1-(dimethylamino)[1- 13 C]alditol which was oxidized in two steps and alkylated with iodomethane to yield L-[4- 13 C]carnitine. The stereochemical integrity at C-2 of the 3-deoxy-D-[1- 13 C]glucose precursor was maintained throughout the synthesis of L-[4- 13 C]carnitine. (author)

  18. Magnetic and micellar effects on photoreactions. 1. 13C isotopic enrichment of dibenzyl ketone via photolysis in aqueous detergent solution

    International Nuclear Information System (INIS)

    Turro, N.J.; Chow, M.F.; Chung, C.J.; Kraeutler, B.

    1981-01-01

    The photolysis of dibenzyl ketone (DBK) in homogeneous organic solutions and in micelle-containing detergent solutions has been investigated from the standpoint of determining the extent and location of 13 C enrichment that occurs. In a series of experiments it is established that for incomplete conversions the residual, recovered DBK is enriched in 13 C relative to the initial unphotolyzed DBK. The efficiency of the 13 C/ 12 C separation is shown to be characterized by an isotope enrichment parameter, α, which is independent of the extent of conversion. A combination of mass spectrometry and nuclear magnetic resonance spectroscopy provides support for the primary location of the 13 C enrichment at C-1 (the carbonyl carbon) with a lesser but significant enrichment at C-2 (the methylene carbon). A very small but experimentally distinct enrichment of the aromatic rings is indicated by 13 C NMR analysis. An isomer of DBK, 1-phenyl-4'-methylacetophenone (PMAP) is formed as a minor product of photolysis in micellar solutions. PMAP, like the recovered, residual DBK, is found to be substantially enriched in 13 C relative to the starting DBK. The magnitude of α is found to be significantly influenced by the application of laboratory magnetic fields to the photolysis sample. The latter result, along with the unusually large magnitude of α, suggests that the mechanism involved in isotopic enrichment is not dominated by kinetic mass isotope effects but rather by nuclear magnetic moment and/or magnetic spin isotope effects

  19. 22 CFR 120.13 - United States.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false United States. 120.13 Section 120.13 Foreign... United States. United States, when used in the geographical sense, includes the several states, the Commonwealth of Puerto Rico, the insular possessions of the United States, the District of Columbia, the...

  20. Probing slowly exchanging protein systems via {sup 13}C{sup {alpha}}-CEST: monitoring folding of the Im7 protein

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Alexandar L.; Bouvignies, Guillaume; Kay, Lewis E., E-mail: kay@pound.med.utoronto.ca [University of Toronto, Departments of Molecular Genetics, Biochemistry and Chemistry (Canada)

    2013-03-15

    A {sup 13}C{sup {alpha}} chemical exchange saturation transfer based experiment is presented for the study of protein systems undergoing slow interconversion between an 'observable' ground state and one or more 'invisible' excited states. Here a labeling strategy whereby [2-{sup 13}C]-glucose is the sole carbon source is exploited, producing proteins with {sup 13}C at the C{sup {alpha}} position, while the majority of residues remain unlabeled at CO or C{sup {beta}}. The new experiment is demonstrated with an application to the folding reaction of the Im7 protein that involves an on-pathway excited state. The obtained excited state {sup 13}C{sup {alpha}} chemical shifts are cross validated by comparison to values extracted from analysis of CPMG relaxation dispersion profiles, establishing the utility of the methodology.

  1. Synthesis of 13C-labelled lactose for metabolic studies in subjects with gastrointestinal disorders

    International Nuclear Information System (INIS)

    Moyna, P.

    1993-01-01

    The long-range goals included development of a 13 C-labelled lactose method for measuring lactose malabsorption in patients with diarrhea. The short-term goals included assembling a nuclear magnetic resonance system and a computer system for spectra analysis. The latter results are the subject of the report. (author)

  2. /sup 13/C-/sup 13/C spin-spin coupling constants in structural investigations. II. Conformational structure of vinyl ethers

    Energy Technology Data Exchange (ETDEWEB)

    Krivdin, L.B.; Shcherbakov, V.V.; Bzhezovskii, V.M.; Kalabin, G.A.

    1986-10-10

    The /sup 13/C-/sup 13/C spin-spin coupling constants between the carbon nuclei of the vinyl group were measured for a series of vinyl ethers. It was established that the unshared electron pairs of the oxygen atom can make a substantial stereospecific contribution to the direct /sup 13/C-/sup 13/C constants of the adjacent nuclei. The observed effect was used to establish the conformational structure of the compounds.

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

    International Nuclear Information System (INIS)

    Stael, Giovanni Chaves; Rocha, Marisa Cristina Guimaraes

    2005-01-01

    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 13 C 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. (author)

  4. [13C] GC-C-IRMS analysis of methylboronic acid derivatives of glucose from liver glycogen after the ingestion of [13C] labeled tracers in rats.

    Science.gov (United States)

    Luengo, Catherine; Azzout-Marniche, Dalila; Fromentin, Claire; Piedcoq, Julien; Lemosquet, Sophie; Tomé, Daniel; Gaudichon, Claire

    2009-11-01

    We developed a complete method to measure low [(13)C] enrichments in glycogen. Fourteen rats were fed a control diet. Six of them also ingested either [U-(13)C] glucose (n=2) or a mixture of 20 [U-(13)C] amino acids (n=4). Hepatic glycogen was extracted, digested to glucose and purified on anion-cation exchange resins. After the optimization of methylboronic acid derivatization using GC-MS, [(13)C] enrichment of extracted glucose was measured by GC-C-IRMS. The accuracy was addressed by measuring the enrichment excess of a calibration curve, which observed values were in good agreement with the expected values (R=0.9979). Corrected delta values were -15.6+/-1.6 delta(13)C (per thousand) for control rats (n=8) and increased to -5 to 8 delta(13)C (per thousand) per thousand and 12-14 delta(13)C (per thousand) per thousand after the ingestion of [U-(13)C] amino acids or [U-(13)C] glucose as oral tracers, respectively. The method enabled the determination of dietary substrate transfer into glycogen. The sequestration of dietary glucose in liver glycogen 4 h after the meal was 35% of the ingested dose whereas the transfer of carbon skeletons from amino acids was only 0.25 to 1%.

  5. Synthesis of [1-.sup.13C]pyruvic acid], [2-.sup.13C]pyruvic acid], [3-.sup.13C]pyruvic acid] and combinations thereof

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Rodolfo A. (Santa Fe, NM), Unkefer; Clifford J. (Los Alamos, NM), Alvarez; Marc, A [Santa Fe, NM

    2012-06-12

    The present invention is directed to the labeled compounds, ##STR00001## wherein C* is each either .sup.13C and .sup.12C where at least one C* is .sup.13C, each hydrogen of the methylene group is hydrogen or deuterium, the methyl group includes either zero or three deuterium atoms, Q is sulfide, sulfinyl, or sulfone, Z is an aryl group such as 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, or a phenyl group ##STR00002## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently either hydrogen, a C.sub.1-C.sub.4 lower alkyl, a halogen, and an amino group such as NH.sub.2, NHR and NRR' where R and R' are each independently either a C.sub.1-C.sub.4 lower alkyl, a phenyl, and an alkoxy group, and the methyl group can include either zero or three deuterium atoms. The present invention is also directed to the labeled compounds ##STR00003##

  6. Influence of the nature of soil organic matter on the sorption behaviour of pentadecane as determined by PLS analysis of mid-infrared DRIFT and solid-state {sup 13}C NMR spectra

    Energy Technology Data Exchange (ETDEWEB)

    Clark Ehlers, G.A. [Institute of Environmental Biotechnology, Department IFA-Tulln, University of Natural Resources and Applied Life Sciences, Vienna, Konrad Lorenz Str. 20, Tulln A-3430 (Austria); Forrester, Sean T. [CSIRO Land and Water, Waite Rd, Urrbrae SA 5064 (Australia); Scherr, Kerstin E. [Institute of Environmental Biotechnology, Department IFA-Tulln, University of Natural Resources and Applied Life Sciences, Vienna, Konrad Lorenz Str. 20, Tulln A-3430 (Austria); Loibner, Andreas P., E-mail: andreas.loibner@boku.ac.a [Institute of Environmental Biotechnology, Department IFA-Tulln, The University of Natural Resources and Applied Life Sciences, Vienna, Konrad Lorenz Str. 20, Tulln A-3430 (Austria); Janik, Les J. [CSIRO Land and Water, Waite Rd, Urrbrae SA 5064 (Australia)

    2010-01-15

    The nature of soil organic matter (SOM) functional groups associated with sorption processes was determined by correlating partitioning coefficients with solid-state {sup 13}C nuclear magnetic resonance (NMR) and diffuse reflectance mid-infrared (DRIFT) spectral features using partial least squares (PLS) regression analysis. Partitioning sorption coefficients for n-pentadecane (n-C{sub 15}) were determined for three alternative models: the Langmuir model, the dual distributed reactive domain model (DRDM) and the Freundlich model, where the latter was found to be the most appropriate. NMR-derived constitutional descriptors did not correlate with Freundlich model parameters. By contrast, PLS analysis revealed the most likely nature of the functional groups in SOM associated with n-C{sub 15} sorption coefficients (K{sub F}) to be aromatic, possibly porous soil char, rather than aliphatic organic components for the presently investigated soils. High PLS cross-validation correlation suggested that the model was robust for the purpose of characterising the functional group chemistry important for n-C{sub 15} sorption. - NMR/IR spectroscopy and chemometrics reveal the aromatic fraction of soil organic matter being responsible for alkane sorption.

  7. Ratio of Gamow-Teller to Fermi strength observed in /sup 13,14/C(p,n) at 492 and 590 MeV

    International Nuclear Information System (INIS)

    Ullmann, J.L.; Rapaport, J.; Lisowski, P.W.

    1988-01-01

    It has been recognized for a number of years that certain spin-isospin components of the nucleon-nucleus effective interaction can be inferred from (p,n) reactions to states of known nuclear structure. For L = 0, S = 0 and L = 0, S = 1 transitions, the 0-degree (p,n) cross section can be related respectively to Fermi and Gamow-Teller beta decay matrix elements. If these transitions occur in the same nucleus, the ratio of isovector spin-flip to non-spin-flip effective interactions can be measured without regard for absolute normalization. The best reaction to measure this is /sup 14/C(p,n) which goes by a pure Gamow-Teller transition to the 1/sup /plus// state at 3.95 MeV in /sup 14/N, and Fermi transition to the 2.31 MeV 0/sup /plus// state. This work extends the ratio measurements made at lower energies (ref. 1, 2, 3) to 492 and 590 MeV. We also report on the /sup 13/C(p,n) reaction which goes by a pure GT transition to the 3.51 MeV 3/2/sup /minus// state in /sup 13/N, but by a mixed Fermi plus Gamow-Teller transition to the 1/2/sup /minus// ground state. 11 refs., 4 figs., 2 tabs

  8. 13 CFR 147.665 - State.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false State. 147.665 Section 147.665... WORKPLACE (NONPROCUREMENT) Definitions § 147.665 State. State means any of the States of the United States... United States. ...

  9. 40 CFR 721.6505 - Polymers of C13C15 oxoalcohol ethoxolates.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymers of C13C15 oxoalcohol... Specific Chemical Substances § 721.6505 Polymers of C13C15 oxoalcohol ethoxolates. (a) Chemical substance... polymers of C13C15 oxoalcohol ethoxolates (PMNs P-96-950/951) are subject to reporting under this section...

  10. Studies to enhance the hyperpolarization level in PHIP-SAH-produced C13-pyruvate

    Science.gov (United States)

    Cavallari, Eleonora; Carrera, Carla; Aime, Silvio; Reineri, Francesca

    2018-04-01

    The use of [1-13C]pyruvate, hyperpolarized by dissolution-Dynamic Nuclear Polarization (d-DNP), in in vivo metabolic studies has developed quickly, thanks to the imaging probe's diagnostic relevance. Nevertheless, the cost of a d-DNP polarizer is quite high and the speed of hyperpolarization process is relatively slow, meaning that its use is limited to few research laboratories. ParaHydrogen Induced Polarization Side Arm Hydrogenation (PHIP-SAH) (Reineri et al., 2015) is a cost effective and easy-to-handle method that produces 13C-MR hyperpolarization in [1-13C]pyruvate and other metabolites. This work aims to identify the main determinants of the hyperpolarization levels observed in C13-pyruvate using this method. By dissecting the various steps of the PHIP-SAH procedure, it has been possible to assess the role of several experimental parameters whose optimization must be pursued if this method is to be made suitable for future translational steps. The search for possible solutions has led to improvements in the polarization of sodium [1-13C]pyruvate from 2% to 5%. Moreover, these results suggest that observed polarization levels could be increased considerably by an automatized procedure which would reduce the time required for the work-up passages that are currently carried out manually. The results reported herein mean that the attainment of polarization levels suitable for the metabolic imaging applications of these hyperpolarized substrates show significant promise.

  11. Synthesis of edatrexate (2-13C-glutamate)

    International Nuclear Information System (INIS)

    DeGraw, J.I.; Colwell, W.T.; Jue, Thomas

    1997-01-01

    The experimental antitumor drug Edatrexate, labeled with 99% 13 C at the 2-position of the glutamate acid group was required for 13 C-magnetic resonance spectroscopy studies in biological media. Coupling of 2,4-diamino-4-deoxy-10-ethyl-10-deazapteroic acid with diethyl L-2- 13 C-glutamate as promoted by BOP reagent afforded Edatrexate (2- 13 C-glu) diethyl ester in 60% yield following purification by column chromatography. Saponification by aqueous NaOH in 2-methoxyethanol gave the target molecule in 44% yield or 26% overall. (author)

  12. Introducing nuclear power into currently non-nuclear states

    International Nuclear Information System (INIS)

    Claassen, Gert

    2007-01-01

    As the nuclear renaissance gains momentum, many countries that currently have no nuclear power plants will begin to consider introducing them. It is anticipated that smaller reactors such as the Pebble Bed Modulator Reactor (PBMR) will not only be sold to current nuclear states to also to states where there is currently no nuclear experience. A range of issues would have to be considered for nuclear plants to be solid to non-nuclear states, such as the appropriate regulatory environment, standardization and codes, non-proliferation, security of supply, obtaining experienced merchant operators, appropriate financial structures and education and training. The paper considers nine major issues that need to be addressed by governments and vendors alike. International cooperation by organisations such as the IAEA, financial institutions and international suppliers will be required to ensure that developing countries as well as developed ones share the benefits of the nuclear renaissance. The opportunities that the nuclear industry affords to develop local skills, create job opportunities and to develop local manufacturing industries are among the important reasons that the South African Government has decided to support and fund the development of the Pebble Bed Modular Reactor project. These considerations are included in the paper. (author)

  13. The C-12/C-13 abundance ratio in Comet Halley

    International Nuclear Information System (INIS)

    Wyckoff, S.; Lindholm, E.; Wehinger, P.A.; Peterson, B.A.; Zucconi, J.M.

    1989-01-01

    The individual (C-13)N rotational lines in Comet Halley are resolved using high-resolution spectra of the CN B2Sigma(+)-X2Sigma(+) (0,0) band. The observe C-12/C-13 abundance ratio excludes a site of origin for the comet near Uranus and Neptune and suggests a condensation environment quite distinct from other solar system bodies. Two theories are presented for the origin of Comet Halley. One theory suggest that the comet originated 4.5 Gyr ago in an inner Oort cloud at a heliocentric distance greater than 100 AU where chemical fractionation led to the C-13 enrichment in the CN parent molecule prior to condensation of the comet nucleus. According to the other, more plausible theory, the comet nucleus condensed relatively recently from the interstellar medium which has become enriches in C-13 and was subsequently gravitationally captured by the solar system. 107 refs

  14. 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.

  15. Sup(13)C NMR studies of glucose disposal in normal and non-insulin-dependent diabetic humans

    International Nuclear Information System (INIS)

    Shulman, G.I.; Rothman, D.L.; Shulman, R.G.

    1990-01-01

    To examine the extent to which the defect in insulin action in subjects with non-insulin-dependent diabetes mellitus (NIDDM) can be accounted for by impairment of muscle glycogen synthesis, we performed combined hyperglycemic-hyperinsulinemic clamp studies with [ 13 C]glucose in five subjects with NIDDM and in six age- and weight-matched healthy subjects. The rate of incorporation of intravenously infused [1- 13 C]glucose into muscle glycogen was measured directly in the gastrocnemius muscle by means of a nuclear magnetic resonance (NMR) spectrometer with a 15.5 min time resolution and a 13 C surface coil. The steady-state plasma concentrations of insulin and glucose were similar in both study groups. The mean (±SE) rate of glycogen synthesis, as determined by 13 C NMR, was 78±28 and 183±39 μmol-glucosyl units (kg muscle tissue (wet mass)) -1 min -1 in the diabetic and normal subjects, respectively. The mean glucose uptake was markedly reduced in the diabetic as compared with the normal subjects. The mean rate of non-oxidative glucose metabolism was 22±4 μmol kg -1 min -1 in the diabetic subjects and 42±4 μmol kg -1 min -1 in the normal subjects. When these rates are extrapolated to apply to the whole body, the synthesis of muscle glycogen would account for most of the total-body glucose uptake and all of the non-oxidative glucose metabolism in both normal and diabetic subjects. We conclude that muscle glycogen synthesis is the principal pathway of glucose disposal in both normal and diabetic subjects and that defects in muscle glycogen synthesis have a dominant role in the insulin resistance that occurs in persons with NIDDM. (author)

  16. Synthesis and purification of 13C labelled xanthine derivatives

    International Nuclear Information System (INIS)

    Boukraa, M.S.; Deruaz, D.; Bannier, A.; Desage, M.; Brazier, J.L.

    1995-01-01

    3-[Methyl- 13 )C]xanthine, 7-[Methyl- 13 )C]xanthine, 1,3-[Dimethyl- 13 )C 2 ]xanthine (theophylline-1,3-[ 13 )CH 3 ] 2 ), 1,7-[Dimethyl- 13 )C 2 ]xanthine (paraxanthine-1,7[ 13 )CH 3 ] 2 ), and 3,7-[Dimethyl- 13 )C 2 ]xanthine (theobromine-3,7-[ 13 )CH 3 ] 2 were synthesized by nucleophilic substitution reaction(SN 2 ) from xanthine (X) and iodomethane-[ 13 C]. The 3-isobutylparaxanthine-7-[ 13 CH 3 ] was prepared from 3-isobutyl-1-methylxanthine (IBMX). The compounds were purified by reverse phase semipreparative liquid chromatography and their chemical structure and purity verified by GC-MS. (Author)

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  18. Solid state nuclear magnetic resonance of fossil fuels

    International Nuclear Information System (INIS)

    Axelson, D.E.

    1985-01-01

    This book contains the following chapters: Principles of solid state NMR; Relaxation processes: Introduction to pulse sequences; Quantitative analysis; Removal of artifacts from CPMAS FT experiments; Line broadening mechanisms; Resolution enhancement of solid state NMR spectra; and /sup 13/C CPMAS NMR of fossil fuels--general applications

  19. The nuclear state

    International Nuclear Information System (INIS)

    Jungk, R.

    1979-01-01

    A general picture is given of the technical and sociological problems which it is said arise in the 'nuclear state'. Separate chapters are entitled: radiation fodder; the gamblers; the atomic man; the intimidated; the proliferators; atomic terrorists; the supervised. The Foreword, entitled 'the hard path' (i.e. with nuclear power) is contrasted with a final chapter entitled 'Prospect: the soft path' (i.e. without nuclear power). (U.K.)

  20. 13C(α,n)16O reaction as the knock-out exchange process

    International Nuclear Information System (INIS)

    Kim, G.; Khajdarov, R.R.; Zaparov, Eh.A.

    2000-01-01

    S-factor for the 13 C(α,n) 16 O reaction is studied. In the framework of the simple phenomenological model this reaction is analysed as neutron knocked-out by α-particle exchange process. The analysis demonstrates the importance of taking into account 2p-state in 13 C. The 13 C(α,n) 16 O cross section is considered both as the knock-out exchange process and as it's combination with process through a compound nucleus. It was shown that for E α s value extrapolated to low energies is found to be noticeably larger that of R-matrix analysis. Different ways of improving the proposed model are discussed. (author)

  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. Accurate determination of 13C/12C in CO2 of past atmospheres from 13C/12C in tree rings by removal of climatic interferences. Final technical progress report

    International Nuclear Information System (INIS)

    Long, A.; Leavitt, S.W.

    1982-07-01

    Analysis of delta 13 C in tree rings offers the potential for reconstructing changes in delta 13 C of atmospheric CO 2 , which combined with 14 C trends will be important in evaluating the past and present role of the biosphere as a net carbon dioxide source or sink. One problem with such tree-ring delta 13 C records is that in addition to changes in atmospheric delta 13 C, climatic factors may influence the isotopic composition of the rings. This study examines delta 13 C in cellulose of five-year intervals of juniper tree rings. The sampling sites were near weather stations for which climate data are readily available. delta 13 C vs winter climate relationships were derived from those sites not under the influence of local pollution sources. These relationships facilitated development of a delta 13 C record from which climate effects have been factored out. The resulting 1930-1979 delta 13 C reconstruction shows a pronounced delta 13 C decrease from 1930 to 1960 and then a post-1960 flattening of the curve. We interpret this trend as representing an increasing role of biospheric CO 2 sinks relative to sources, although other interpretations may be possible within the limits of precision of data analysis. Research with this technique is continuing with pinyon pine and dendroclimatological reconstructions to verify these results and to develop a climate-free delta 13 C chronology back to pre-industrial time

  3. Detection of antisymmetric tensor contribution to the magnetic screening of 13C nuclei

    International Nuclear Information System (INIS)

    Kuhn, W.

    1983-01-01

    In the present thesis for the first time a practicable way for the detection of antisymmetric contributions to the tensor of the magnetic screening of atomic nuclei is indicated. The detection is based on the relaxation efficiency of the antisymmetric screening. The measurements were performed on the 13 C nuclei of phthalic acid anhydride. Measured were the spin-lattice relaxation times of all 13 C nuclei of the molecule at field strengths between 4.69 T and 11.74 T, this corresponds to 1 H resonance frequencies in the range from 200 MHz to 500 MHz. From this the interaction-specific relaxation rates could be determined without problems. The space-group of the crystal and the molecule geometry were determined by X-ray structure analysis. For the accurate determination of the hydrogen position on a deuterated monocrystal by means of deuterium nuclear resonance measurements the electric field gradient tensors were measured and from the orientation of the main axes of these tensors the bonding angles calculated. On a monocrystal enriched in the C(7) respectively C(8) position with 13 C the symmetric part of the tensor of the magnetic screening of these two nuclei was measured. With these values and the relaxation rates of the 13 C nuclei by an iterative procedure from the equations for the theoretical relaxation rates of all 13 C nuclei of the molecule the main values of the rotation-diffusion tensor could be determined. On the base of the plane molecule geometry from this the tensor element sigmasub(xz)sup(A) could be explicety detected according to an amount of 11.7 ppm. (orig.) [de

  4. Simultaneous Hyperpolarized 13C-Pyruvate MRI and 18F-FDG PET (HyperPET) in 10 Dogs with Cancer

    DEFF Research Database (Denmark)

    Gutte, Henrik; Hansen, Adam E; Larsen, Majbrit M E

    2015-01-01

    with biopsy-verified spontaneous malignant tumors were included for imaging. All dogs underwent a protocol of simultaneous (18)F-FDG PET, anatomic MR, and hyperpolarized dynamic nuclear polarization with (13)C-pyruvate imaging. The data were acquired using a combined clinical PET/MR imaging scanner. We found...... that combined (18)F-FDG PET and (13)C-pyruvate MRS imaging was possible in a single session of approximately 2 h. A continuous workflow was obtained with the injection of (18)F-FDG when the dogs was placed in the PET/MR scanner. (13)C-MRS dynamic acquisition demonstrated in an axial slab increased (13)C......With the introduction of combined PET/MR spectroscopic (MRS) imaging, it is now possible to directly and indirectly image the Warburg effect with hyperpolarized (13)C-pyruvate and (18)F-FDG PET imaging, respectively, via a technique we have named hyperPET. The main purpose of this present study...

  5. Excitation of nuclear states by synchrotron radiation

    International Nuclear Information System (INIS)

    Olariu, Albert

    2003-01-01

    We study the excitation of nuclear states by gamma ray beams of energy up to 200 keV produced as synchrotron radiation. We consider the possibility to populate an excited state |i> in two steps, from the ground state |g> to an intermediary state |n> which decays by gamma emission or internal conversion to a lower state |i>. The aim of this study is to establish that the probability P 2 of the two-step transition |g> → |n> → |i> should be greater than the probability P 1 of the direct transition |g> → |i>. The probabilities P 1 and P 2 correspond to a radiation pulse of duration equal to the half-time of the state |i>. We have written a computer program in C++ which computes the probability P 2 , the ratio P 2 /P 1 and the rate C 2 of the two-step transitions for any nuclei and different configurations of states. The program uses a database which contains information on the energy levels, half-lives, spins and parities of nuclear states and on the relative intensities of the nuclear transitions. If the half-lives or the relative intensities are not known the program uses the Weisskopf estimates for the transition half-lives. An interpolation program of internal conversion coefficients has also been used. We listed the values obtained for P 2 , P 2 /P 1 and C 2 in a number of cases in which P 2 is significant from the 2900 considered cases. The states |i> and |n> have the energies E i and E n , the corresponding half-lives being t i and t n . The spectral density of the synchrotron radiation has been considered to be 10 12 photons cm -2 s -1 eV -1 . We listed only the cases for which the relative intensities of the transitions from levels |n> and |i> to lower states are known. The calculations carried out in this study allowed us to identify nuclei for which P 2 has relatively great values. In the listed cases P 2 /P 1 >>1, so that the two-step excitation by synchrotron radiation is more efficient than the direct excitation |g> → |i>. For a sample having 10

  6. Technical advances in neutron polarimetry and studies of the (p,n) reaction in /sup 13/C

    Energy Technology Data Exchange (ETDEWEB)

    Videla, N G

    1985-01-01

    The asymmetry in the /sup 4/He(p,n vector)/sup 4/He reaction has been measured at three different incident neutron energies: 19.40; 22.85 and 27.31 MeV, and 120/sup 0/ from forward direction. Values of the asymmetry have been used to calculate the polarization of fast neutrons produced in the /sup 13/C(p,n vector)/sup 13/N. The /sup 13/C(p,n vector)/sup 13/N reaction was studied as part of a program being undertaken at the University of Manitoba Cyclotron Laboratory to study (p,n) reactions linking isobaric analog states of mirror nuclei in the energy range of 22 to 50 MeV. The study involves a comparison of the proton analyzing power A(theta), in the reaction /sup 13/C(vector p,n)/sup 13/N to the neutron polarization in the inverse reaction /sup 13/C(p,n vector)/sup 13/N. The importance of the comparison between these two observables is based in Conzett's theorem for time reversed reactions, the theorem states that the proton analyzing power in the reaction /sup 13/C(vector p,n)/sup 13/N is equal to the neutron polarization in the reaction /sup 13/C(p,n vector)/sup 13/N provided the reaction proceeds between members of an isospin doublet and when charge symmetry and time reversal invariance hold exactly. However, isospin symmetry is broken by the Coulomb interaction. So comparison of these two observables should yield information of the breaking of isospin by the Coulomb force.

  7. Introducing nuclear power into currently non-nuclear states

    International Nuclear Information System (INIS)

    Gert, Claassen

    2007-01-01

    As the nuclear renaissance gains momentum, many countries that currently have no nuclear power plants will begin to consider introducing them. It is anticipated that smaller reactors such as the Pebble Bed Modular Reactor (PBMR) will not only be sold to current nuclear states to also to states where there is currently no nuclear experience. A range of issues would have to be considered for nuclear plants to be sold to non-nuclear states, such as the appropriate regulatory environment, standardization and codes, non-proliferation, security of supply, obtaining experienced merchant operators, appropriate financial structures and education and training. The paper considers nine major issues that need to be addressed by governments and vendors alike: 1) political enabling framework, 2) regulatory framework, 3) responsible owner, 4) responsible operator, 5) finance, 6) contact management, 7) fuel supply and waste management framework, 8) training and education, and 9) industrial infrastructure. International cooperation by organisations such as the IAEA, financial institutions and international suppliers will be required to ensure that developing countries as well as developed ones share the benefits of the nuclear renaissance. The opportunities that the nuclear industry affords to develop local skills, create job opportunities and to develop local manufacturing industries are among the important reasons that the South African Government has decided to support and fund the development of the Pebble Bed Modular Reactor project. (author)

  8. 13C and 31P NMR studies of myocardial metabolism

    International Nuclear Information System (INIS)

    Laughlin, M.R.

    1988-01-01

    The fluxes through two enzyme systems have been measured in perfused or in in vivo heart using NMR: phosphocreatine kinase, and glycogen synthase and phosphorylase. The rates of synthesis and degradation of glycogen were monitored in vivo in fed, fasted, and diabetic rat heart during infusions of 13 C-1-glucose and insulin using proton-decoupled 13 C-NMR at 1.9 and 4.7 tesla. The enzyme activities of glycogen synthase and glycogen phosphorylase were also measured in this tissue which had been freeze clamped at the end of the experiment, for comparison with the synthetic rates. For normal fed, fasted, and diabetic animals, synthesis rates were 0.28, 0.16, and 0.15 μmol/min.gww respectively. Glycogen synthase i activity was 0.23, 0.14, and 0.14 μmol/min.gww in these hearts at the end of the experiment, when measured at appropriate substrate and activator concentrations, and follow activation time courses that are consistent with being the main rate determinant for net synthesis in all cases. Turnover of glycogen was studied by observing the preformed 13 C-1-glycogen signal during infusion of 12 C-glucose and insulin, and was found to be close to zero. Extracted phosphorylase a activity was approximately ten times that of synthase i under these circumstances. In order to fully interpret the turnover studies, glycogenolysis of preformed 13 C-glycogen was observed after a bolus of glucagon. The glycogen had either been synthesized from 13 C-1-glucose for a single hour, or during an hour of 13 C-glucose and a subsequent hour of 12 C-glucose infusion. The author observed that breakdown follows an exponential time course related to the phosphorylase a activation state and that the last synthesized glycogen breaks down at the rate of 2.5 μmol/min.gww, five times faster than that synthesized an hour earlier

  9. Measuring 13Cβ chemical shifts of invisible excited states in proteins by relaxation dispersion NMR spectroscopy

    International Nuclear Information System (INIS)

    Lundstroem, Patrik; Lin Hong; Kay, Lewis E.

    2009-01-01

    A labeling scheme is introduced that facilitates the measurement of accurate 13 C β chemical shifts of invisible, excited states of proteins by relaxation dispersion NMR spectroscopy. The approach makes use of protein over-expression in a strain of E. coli in which the TCA cycle enzyme succinate dehydrogenase is knocked out, leading to the production of samples with high levels of 13 C enrichment (30-40%) at C β side-chain carbon positions for 15 of the amino acids with little 13 C label at positions one bond removed (∼5%). A pair of samples are produced using [1- 13 C]-glucose/NaH 12 CO 3 or [2- 13 C]-glucose as carbon sources with isolated and enriched (>30%) 13 C β positions for 11 and 4 residues, respectively. The efficacy of the labeling procedure is established by NMR spectroscopy. The utility of such samples for measurement of 13 C β chemical shifts of invisible, excited states in exchange with visible, ground conformations is confirmed by relaxation dispersion studies of a protein-ligand binding exchange reaction in which the extracted chemical shift differences from dispersion profiles compare favorably with those obtained directly from measurements on ligand free and fully bound protein samples

  10. Determination of fructose metabolic pathways in normal and fructose-intolerant children: A 13C NMR study using [U-13C]fructose

    International Nuclear Information System (INIS)

    Gopher, A.; Lapidot, A.; Vaisman, N.; Mandel, H.

    1990-01-01

    An inborn deficiency in the ability of aldolase B to split fructose 1-phosphate is found in humans with hereditary fructose intolerance (HFI). A stable isotope procedure to elucidate the mechanism of conversion of fructose to glucose in normal children and in HFI children has been developed. A constant infusion of D-[U- 13 C]fructose was given nasogastrically to control and to HFI children. Hepatic fructose conversion to glucose was estimated by examination of 13 C NMR spectra of plasma glucose. Significantly lower values (∼3-fold) for fructose conversion to glucose were obtained for the HFI patients as compared to the controls. A quantitative determination of the metabolic pathways of fructose conversion to glucose was derived from 13 C NMR measurement of plasma [ 13 C]glucose isotopomer populations. The finding of isotopomer populations of three adjacent 13 C atoms at glucose C-4 ( 13 C 3 - 13 C 4 - 13 C 5 ) suggests that there is a direct pathway from fructose, by-passing fructose-1-phosphate aldolase, to fructose 1,6-bisphosphate. The metabolism of fructose by fructose-1-phosphate aldolase activity accounts for only ∼50% of the total amount of hepatic fructose conversion to glucose. In view of the marked decline by 67% in synthesis of glucose from fructose in HFI subjects found in this study, the extent of [ 13 C]glucose formation from a trace amount of [U- 13 C]fructose infused into the patient can be used as a safe and noninvasive diagnostic test for inherent faulty fructose metabolism

  11. Iran: the next nuclear threshold state?

    OpenAIRE

    Maurer, Christopher L.

    2014-01-01

    Approved for public release; distribution is unlimited A nuclear threshold state is one that could quickly operationalize its peaceful nuclear program into one capable of producing a nuclear weapon. This thesis compares two known threshold states, Japan and Brazil, with Iran to determine if the Islamic Republic could also be labeled a threshold state. Furthermore, it highlights the implications such a status could have on U.S. nonproliferation policy. Although Iran's nuclear program is mir...

  12. Asymptotic normalization coefficients, nuclear vertex constants and nuclear astrophysics problems

    International Nuclear Information System (INIS)

    Yarmukhamedov, R.; Artemov, S.V.; Igamov, S.B.; Burtebaev, N.; Peterson, R.J.

    2007-01-01

    Full text: We will review the results of a comprehensive analysis of the experimental astrophysical S- factors S(E) for the t(α, γ ) 7 Li, 3 He(α, γ) 7 Be, 7 Be(p, γ) 8 B, 12 C(p , γ) 13 N and 13 C(p,γ) 14 N reactions at extremely low energies, performed within a three-sided collaboration (Uzbekistan-Kazakhstan-USA). In the analysis, the new experimental data for the 12 C(p, γ) 13 N reaction are also included, as measured with the accelerator UKP-2-1 at the Institute of Nuclear Physics in Kazakhstan. The analysis is carried out within the framework of a new two-body potential approach and the R-matrix method, taking into account information about the asymptotic normalization coefficient (ANC) (or the respective nuclear vertex constant for virtual decay of the residual nuclei into two fragments of the initial states of the aforesaid reactions, which belong to the fundamental nuclear constants). Nowadays ANC's are obtained from analysis of peripheral one nucleon transfer reactions by method combining dispersion theory and DWBA (CM). It is shown that ANC can be also reliably obtained from analysis of proton capture reactions at astrophysical energies by new modified two-body potential method where the CM is used. A comparative analysis of the results obtained by different authors in the framework of different methods is also done

  13. Generating highly polarized nuclear spins in solution using dynamic nuclear polarization

    DEFF Research Database (Denmark)

    Wolber, J.; Ellner, F.; Fridlund, B.

    2004-01-01

    A method to generate strongly polarized nuclear spins in solution has been developed, using Dynamic Nuclear Polarization (DNP) at a temperature of 1.2K, and at a field of 3.354T, corresponding to an electron spin resonance frequency of 94GHz. Trityl radicals are used to directly polarize 13C...... and other low-γ nuclei. Subsequent to the DNP process, the solid sample is dissolved rapidly with a warm solvent to create a solution of molecules with highly polarized nuclear spins. Two main applications are proposed: high-resolution liquid state NMR with enhanced sensitivity, and the use...

  14. Solution and solid state NMR studies of the structure and dynamics of C60 and C70

    International Nuclear Information System (INIS)

    Johnson, R.D.; Yannoni, C.S.; Salem, J.; Meijer, G.; Bethune, D.S.

    1991-01-01

    This paper investigates the structure and dynamics of C 60 and C 70 with 13 C NMR spectroscopy. In solution, high-resolution spectra reveal that C 60 has a single resonance at 143 ppm, indicating a strained, aromatic system with high symmetry. This is strong evidence for a C 60 soccer ball geometry. A 2D NMR INADEQUATE experiment on 13 C-enriched C 70 reveals the bonding connectivity to be a linear string, in firm support of the proposed rugby ball structure with D 5h symmetry, and furnishes resonance assignments. Solid state NMR spectra of C 60 at ambient temperatures yield a narrow resonance, indicative of rapid molecular reorientation. Variable temperature T 1 measurements show that the rotational correlation time is ∼ 10 - 9 s at 230 K. At 77 K, this time increases to more than 1 ms, and the 13 C NMR spectrum of C 60 is a powder pattern due to chemical shift anisotropy (tensor components 220, 186, 40 ppm). At intermediate temperatures a narrow peak is superimposed on the powder pattern, suggesting a distribution of barriers to molecular motion in the sample, or the presence of an additional phase in the solid state. A Carr-Purcell dipolar experiment on C 60 in the solid state allows the first precise determination of the C 60 bond lengths: 1.45 and 1.40 Angstrom

  15. Biokinetics of 13C in the human body after oral administration of 13C-labeled glucose as an index for the biokinetics of 14C.

    Science.gov (United States)

    Masuda, Tsuyoshi; Tako, Yasuhiro; Matsushita, Kensaku; Takeda, Hiroshi; Endo, Masahiro; Nakamura, Yuji; Hisamatsu, Shun'ichi

    2016-09-01

    The retention of 13 C in the human body after oral administration of 13 C-labeled glucose was studied in three healthy volunteer subjects to estimate the 50 year cumulative body burden for 13 C as an index of the committed dose of the radioisotope 14 C. After administration of 13 C-labeled glucose, the volunteers ingested controlled diets with a fixed number of calories for 112 d. Samples of breath and urine were collected up to 112 d after administration. Samples of feces were collected up to 14 d after administration. Hair samples were obtained at 119 d after administration and analyzed as a representative index of the rate of excretion of organic 13 C via pathways such as skin cell exfoliation and mucus secretion. All samples were analyzed for 13 C/ 12 C atomic ratio to determine the rate of excretion via each pathway. We then constructed a metabolic model with a total of four pathways (breath, urine, feces, and other) comprising seven compartments. We determined the values of the biokinetic parameters in the model by using the obtained excretion data. From 74% to 94% of the 13 C administered was excreted in breath, whereas    0.1). In addition, the dataset for one of the three subjects was markedly different from those of the other two. When we estimated the 50 year cumulative body burden for 13 C by using our model and we included non-statistically significant parameters, a considerable cumulative body burden was found in the compartments excreting to the other pathway. Although our results on the cumulative body burden of 13 C from orally administered carbon as glucose were inconclusive, we found that the compartments excreting to the other pathway had a markedly long residence time and therefore should be studied further to clarify the fate of carbon in the human body. In addition to excreta, data for serum and blood cell samples were also collected from the subjects to examine the metabolism of 13 C in human body.

  16. 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...

  17. Reorientation-effect measurement of the first 2+ state in 12C: Confirmation of oblate deformation

    Science.gov (United States)

    Kumar Raju, M.; Orce, J. N.; Navrátil, P.; Ball, G. C.; Drake, T. E.; Triambak, S.; Hackman, G.; Pearson, C. J.; Abrahams, K. J.; Akakpo, E. H.; Al Falou, H.; Churchman, R.; Cross, D. S.; Djongolov, M. K.; Erasmus, N.; Finlay, P.; Garnsworthy, A. B.; Garrett, P. E.; Jenkins, D. G.; Kshetri, R.; Leach, K. G.; Masango, S.; Mavela, D. L.; Mehl, C. V.; Mokgolobotho, M. J.; Ngwetsheni, C.; O'Neill, G. G.; Rand, E. T.; Sjue, S. K. L.; Sumithrarachchi, C. S.; Svensson, C. E.; Tardiff, E. R.; Williams, S. J.; Wong, J.

    2018-02-01

    A Coulomb-excitation reorientation-effect measurement using the TIGRESS γ-ray spectrometer at the TRIUMF/ISAC II facility has permitted the determination of the 〈 21+ ‖ E 2 ˆ ‖21+ 〉 diagonal matrix element in 12C from particle-γ coincidence data and state-of-the-art no-core shell model calculations of the nuclear polarizability. The nuclear polarizability for the ground and first-excited (21+) states in 12C have been calculated using chiral NN N4LO500 and NN+3NF350 interactions, which show convergence and agreement with photo-absorption cross-section data. Predictions show a change in the nuclear polarizability with a substantial increase between the ground state and first excited 21+ state at 4.439 MeV. The polarizability of the 21+ state is introduced into the current and previous Coulomb-excitation reorientation-effect analyses of 12C. Spectroscopic quadrupole moments of QS (21+) = + 0.053 (44) eb and QS (21+) = + 0.08 (3) eb are determined, respectively, yielding a weighted average of QS (21+) = + 0.071 (25) eb, in agreement with recent ab initio calculations. The present measurement confirms that the 21+ state of 12C is oblate and emphasizes the important role played by the nuclear polarizability in Coulomb-excitation studies of light nuclei.

  18. The state of nuclear forensics

    International Nuclear Information System (INIS)

    Kristo, Michael J.; Tumey, Scott J.

    2013-01-01

    Nuclear terrorism has been identified as one of the most serious security threats facing the world today. Many countries, including the United States, have incorporated nuclear forensic analysis as a component of their strategy to prevent nuclear terrorism. Nuclear forensics involves the laboratory analysis of seized illicit nuclear materials or debris from a nuclear detonation to identify the origins of the material or weapon. Over the years, a number of forensic signatures have been developed to improve the confidence with which forensic analysts can draw conclusions. These signatures are validated and new signatures are discovered through research and development programs and in round-robin exercises among nuclear forensic laboratories. The recent Nuclear Smuggling International Technical Working Group Third Round Robin Exercise and an on-going program focused on attribution of uranium ore concentrate provide prime examples of the current state of nuclear forensics. These case studies will be examined and the opportunities for accelerator mass spectrometry to play a role in nuclear forensics will be discussed.

  19. The state of nuclear forensics

    Energy Technology Data Exchange (ETDEWEB)

    Kristo, Michael J. [Chemical Sciences Division, Lawrence Livermore National Laboratory, P.O. Box 808, L-186, Livermore, CA 94551 (United States); Tumey, Scott J., E-mail: tumey2@llnl.gov [Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, P.O. Box 808, L-397, Livermore, CA 94551 (United States)

    2013-01-15

    Nuclear terrorism has been identified as one of the most serious security threats facing the world today. Many countries, including the United States, have incorporated nuclear forensic analysis as a component of their strategy to prevent nuclear terrorism. Nuclear forensics involves the laboratory analysis of seized illicit nuclear materials or debris from a nuclear detonation to identify the origins of the material or weapon. Over the years, a number of forensic signatures have been developed to improve the confidence with which forensic analysts can draw conclusions. These signatures are validated and new signatures are discovered through research and development programs and in round-robin exercises among nuclear forensic laboratories. The recent Nuclear Smuggling International Technical Working Group Third Round Robin Exercise and an on-going program focused on attribution of uranium ore concentrate provide prime examples of the current state of nuclear forensics. These case studies will be examined and the opportunities for accelerator mass spectrometry to play a role in nuclear forensics will be discussed.

  20. Inspection of licensed nuclear power plants in the United States

    International Nuclear Information System (INIS)

    Thornburg, H. D.

    1977-01-01

    Inspection of licensed nuclear power plants in the United States is performed by the Office of Inspection and Enforcement (IE), United States Nuclear Regulatory Commission. IE has several key functions : a) Inspection of licensees and investigation of incidents, occurrences and allegations. b) Detection and correction of safety and security problems. c) Enforcement of rules, regulations, and Commission orders. d) Feedback to the industry and others regarding safety experience. e) Informing the public and others. Major enforcement actions and events involving operating power reactors for the past several years will be summarized. (author)

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

    Science.gov (United States)

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

    1996-01-01

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

  2. Excitation functions of the systems 12C+14C and 13C+12C

    International Nuclear Information System (INIS)

    Haindl, E.

    1975-01-01

    The excitation functions of the systems 12 C+ 14 C and 13 C+ 12 C are investigated for different exit channels. The excitation functions measured do not show correlated structures as in the system 12 C+ 12 C. (WL/AK) [de

  3. Study of the reinforcement of rubber styrene-butadiene with mesoporous silices by solid-state nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Sierra, Ligia; Lopez, Betty; Pena, Bibiana; Rios, Juan Esteban; Castano, Nelson

    2001-01-01

    The knowledge about the interaction rubber/filler for the rubber reinforced with carbon black of silica is important to understand the physical properties, which determine the reinforcement. This paper presents a comparative study of the interactions between styrene butadiene rubber (SBR) and silica for a silica Ultrasil type and mesoporous silica MCM-41 type prepared by different procedures, based on solid state nuclear magnetic resonance: 1H MAS NMR; 13C MAS NMR, 13C CP/MAS, 29Si MAS and 29Si CP/MAS NMR. Mesoporous silica synthesized under certain specific conditions showed better interaction with the rubber than the ultrasil VN3 silica, commonly used as a reinforcement load. Mechanical tests for the SBR vulcanised with this silica indicate an important increase for values of elongation and tearing resistance, but an increase in the vulcanization time in it is compared with the SBR vulcanise with Ultrasil

  4. Estimates of methyl 13C and 1H CSA values (Δσ) in proteins from cross-correlated spin relaxation

    International Nuclear Information System (INIS)

    Tugarinov, Vitali; Scheurer, Christoph; Brueschweiler, Rafael; Kay, Lewis E.

    2004-01-01

    Simple pulse schemes are presented for the measurement of methyl 13 C and 1 H CSA values from 1 H- 13 C dipole/ 13 C CSA and 1 H- 13 C dipole/ 1 H CSA cross-correlated relaxation. The methodology is applied to protein L and malate synthase G. Average 13 C CSA values are considerably smaller for Ile than Leu/Val (17 vs 25 ppm) and are in good agreement with previous solid state NMR studies of powders of amino acids and dipeptides and in reasonable agreement with quantum-chemical DFT calculations of methyl carbon CSA values in peptide fragments. Small averaged 1 H CSA values on the order of 1 ppm are measured, consistent with a solid state NMR determination of the methyl group 1 H CSA in dimethylmalonic acid

  5. Natural (13) C distribution in oil palm (Elaeis guineensis Jacq.) and consequences for allocation pattern.

    Science.gov (United States)

    Lamade, Emmanuelle; Tcherkez, Guillaume; Darlan, Nuzul Hijri; Rodrigues, Rosario Lobato; Fresneau, Chantal; Mauve, Caroline; Lamothe-Sibold, Marlène; Sketriené, Diana; Ghashghaie, Jaleh

    2016-01-01

    Oil palm has now become one of the most important crops, palm oil representing nearly 25% of global plant oil consumption. Many studies have thus addressed oil palm ecophysiology and photosynthesis-based models of carbon allocation have been used. However, there is a lack of experimental data on carbon fixation and redistribution within palm trees, and important C-sinks have not been fully characterized yet. Here, we carried out extensive measurement of natural (13) C-abundance (δ(13) C) in oil palm tissues, including fruits at different maturation stages. We find a (13) C-enrichment in heterotrophic organs compared to mature leaves, with roots being the most (13) C-enriched. The δ(13) C in fruits decreased during maturation, reflecting the accumulation in (13) C-depleted lipids. We further used observed δ(13) C values to compute plausible carbon fluxes using a steady-state model of (13) C-distribution including metabolic isotope effects ((12) v/(13) v). The results suggest that fruits represent a major respiratory loss (≈39% of total tree respiration) and that sink organs such as fruits are fed by sucrose from leaves. That is, glucose appears to be a quantitatively important compound in palm tissues, but computations indicate that it is involved in dynamic starch metabolism rather that C-exchange between organs. © 2015 John Wiley & Sons Ltd.

  6. Inference of past atmospheric delta13C and P/sub CO2/ from 13C/12C measurements in tree rings

    International Nuclear Information System (INIS)

    Leavitt, S.W.

    1982-01-01

    Carbon dioxide release from fossil-fuel burning is significant enough that we may soon experience perceptible changes in climate with important human consequences. An accurate reconstruction of past 13 C/ 12 C ratios of atmospheric CO 2 may provide key constraints on the historical activity of the biosphere as CO 2 source or sink. Tree rings appear to be a repository of this information but there is much noise in the collection of previous reconstructions, presumably associated with site selection, radial variability, choice of representative wood chemical constituent, and subtle effects of climate on fractionation. This study attempts to avoid these pitfalls and develop a 50-yr delta 13 C/sub ATM/ record from juniper trees (genus Juniperus), in fact, by taking advantage of the influence of climate on fractionation. Trees were harvested from suitable sites in close proximity to weather stations with monthly records of temperature and precipitation. The most useful relationships for at most 7 of the 10 sites were delta 13 C with December temperature or precipitation, because the coefficients were nearly constant from one interval to the next and the intercepts differed. Local pollution effects are believed responsible for the three anomalous sites. The separation of these regression lines of different intervals is interpreted as the response of the trees to the changing delta 13 C of atmospheric CO 2 so that delta 13 C/sub ATM/ curves are constructed from this spacing. The shape of the best-fit reconstruction suggests the biosphere has acted as CO 2 source to about 1965 and may now be a net sink

  7. Synthesis and applications of 13C glycerol

    International Nuclear Information System (INIS)

    Stocking, E.; Khalsa, O.; Martinez, R.; Silks, L.A. III

    1994-01-01

    The authors are currently developing new synthetic routes to the various isotopomers of glycerol. Labeled glycerol is useful for 13 C enrichment of biomolecules. However, traditional methods of glycerol synthesis are not easily adapted for isotopic enrichment or have poor overall yields (12-15%). In addition, the use of glycerol for enrichment can be prohibitively expensive and its availability depends on the level of demand. The authors have developed a short de novo synthesis of [U- 13 C]glycerol from carbon dioxide (∼53% overall yield for four steps) and are currently examining the feasibility of synthesizing site-specific 13 C labeled glycerol and dihydroxyacetone (DHA) from methanol and carbon dioxide. The authors have examined the enzymatic conversion of [U- 13 C]glycerol to glyceraldehyde-3-monophosphate or dihydroxyacetone monophosphate (DHAP) with yields ranging from 25-50% (as determined by NMR spectroscopy). The authors are also pursuing the chemical conversion of 13 C labeled DHA to DHAP and the results are presented. Labeled DHAP is a possible enzymatic precursor for both labeled 2-deoxyribose and 2-deoxyribonucleic acids

  8. Reaction 12C(16O,α)24Mg leading to nuclear molecular resonances

    International Nuclear Information System (INIS)

    Nagatani, K.; Shimoda, T.; Tanner, D.; Tribble, R.; Yamaya, T.

    1979-01-01

    The reactions 12 C( 16 O,α) 24 Mg and 13 C( 16 O,α) 25 Mg were investigated at an incident energy of 145 MeV. In the reaction with the 12 C target, broad peaks are observed at forward angles which correspond to the molecular resonance states of the 12 C+ 12 C system, while the spectra with 13 C target show only a smooth continuum

  9. Characterization and Comparison of Fast Pyrolysis Bio-oils from Pinewood, Rapeseed Cake, and Wheat Straw Using 13C NMR and Comprehensive GC × GC

    NARCIS (Netherlands)

    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.

    2016-01-01

    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

  10. In vivo 13C MRS studies of carbohydrate metabolism

    International Nuclear Information System (INIS)

    Halliday, Jane

    2003-01-01

    The work described in this thesis was performed by the author, except where indicated, within the Magnetic Resonance Centre at the University of Nottingham during the period between October 1999 and October 2002. Although much is known about the major pathways of carbohydrate metabolism, there is still much to be learnt about the exact mechanisms of many of these pathways. Of particular interest is how these pathways are modified under different physiological conditions and in diseased states. 13 C NMR spectroscopy provides a non-invasive means for studying carbohydrate metabolism in vivo, and the work presented within this thesis gives two such examples of this in human subjects. Natural abundance 13 C NMR spectroscopy was used to measure glycogen levels in gastrocnemius muscle. The diurnal changes in response to mixed meals were measured in both type 2 diabetic subjects and age and weight matched controls. Metabolic studies were performed to complement the NMR measurements. The data obtained in these studies show the effect of the failure of muscle glucose storage upon post-prandial hyperglycaemia despite a supra-normal increase in plasma insulin in type 2 diabetes. 13 C NMR spectroscopy was also used to study cerebral metabolism. Accumulation of 13 C label into glutamate and glutamine following infusion of [1 1 3 C] glucose allows the determination of the rates of the TCA cycle (F TCA ) and neurotransmitter cycling (F cyc ). These rates were measured in the visual cortex under control and activated conditions. The increases seen in F TCA upon activation, together with the lack of label accumulation in lactate, suggest that cerebral glucose metabolism is oxidative, even during strong activation. No conclusion can be made as to whether or not a similar increase is seen in F cyc due to the large associated errors in these values. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Eldridge, S.M., E-mail: simon.eldridge@dpi.nsw.gov.au [Environmental Futures Centre, School of Environment, Griffith University, Nathan, QLD 4111 (Australia); NSW Department of Primary Industries, Bruxner Highway, Wollongbar, NSW 2477 (Australia); Chen, C.R. [Environmental Futures Centre, School of Environment, Griffith University, Nathan, QLD 4111 (Australia); Xu, Z.H. [Environmental Futures Centre, School of Biomolecular and Physical Sciences, Griffith University, Nathan, QLD 4111 (Australia); Nelson, P.N. [School of Earth and Environmental Sciences, James Cook University, Cairns, QLD 4870 (Australia); Boyd, S.E. [Environmental Futures Centre, School of Biomolecular and Physical Sciences, Griffith University, Nathan, QLD 4111 (Australia); Meszaros, I. [Formerly NSW Department of Primary Industries, Richmond, NSW 2753 (Australia); Chan, K.Y. [Graduate School of Environment, Macquarie University, North Ryde, NSW 2109 (Australia); Formerly NSW Department of Primary Industries, Richmond, NSW 2753 (Australia)

    2013-11-15

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

  12. An overview of the metabolic differences between Bradyrhizobium japonicum 110 bacteria and differentiated bacteroids from soybean (Glycine max) root nodules: an in vitro 13C- and 31P-nuclear magnetic resonance spectroscopy study

    International Nuclear Information System (INIS)

    Vauclare, Pierre; Bligny, Richard; Gout, Elisabeth; Widmer, Francois

    2013-01-01

    Bradyrhizobium japonicum is a symbiotic nitrogen-fixing soil bacteria that induce root nodules formation in legume soybean (Glycine max.). Using 13 C- and 31 P-nuclear magnetic resonance (NMR) spectroscopy, we have analysed the metabolite profiles of cultivated B. japonicum cells and bacteroids isolated from soybean nodules. Our results revealed some quantitative and qualitative differences between the metabolite profiles of bacteroids and their vegetative state. This includes in bacteroids a huge accumulation of soluble carbohydrates such as trehalose, glutamate, myo-inositol and homo-spermidine as well as Pi, nucleotide pools and intermediates of the primary carbon metabolism. Using this novel approach, these data show that most of the compounds detected in bacteroids reflect the metabolic adaptation of rhizobia to the surrounding microenvironment with its host plant cells. (authors)

  13. Laboratory spectra of C-13 ethane

    Science.gov (United States)

    Kurtz, Joe; Reuter, Dennis C.; Jennings, Donald E.; Hillman, John J.

    1991-01-01

    The laboratory infrared spectrum of C-13 monosubstituted ethane has been obtained at high resolution (0.0025/cm) using the McMath Fourier transform spectrometer at Kitt Peak National Observatory in May 1990. A preliminary analysis of the nu12 rQ0 branch (substituted species) suggests that its intensity is 1.15 + or - 0.05 times stronger than the equivalent nu9 branch in the normal (C-12)2H6 species. This result leads to a correction of a previously published estimate for the C-12/C-13 ratio in the atmosphere of Jupiter from about 94 to about 106.

  14. NMR study of conjugation effects. 15. /sup 13/C-/sup 13/C spin-spin coupling constants in phenylalkyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Kalabin, G.A. (Siberian Branch of the Academy of Sciences of the USSR); Krivdin, L.B.; Trofimov, B.A.

    1982-07-20

    In order to elucidate the /sup 13/C-/sup 13/-C SSCC (spin-spin coupling constants) segment with the electronic excitations induced by the R group, a series of phenyl alkyl ethers, PhOAlk, where Alk = Me(I), Et(II), i-Pr(III), and t-Bu(IV), were studied. This series was chosen because in studying the /sup 13/C CS in monosubstituted benzenes it was observed that the intensity of the ..pi..-electron interaction of the unshared electron pairs of oxygen with the ..pi.. system of the benzene ring was practically the same in some compounds, but increased by 30% in others. This is related to the fact that the latter is characterized by an average noncoplanar conformation, with a dihedral angle between the benzene-ring plane and the C-O-C bond of approx. 45/sup 0/, whereas some compounds have an angle < 20/sup 0/. The reason for the difference is significant steric interaction of the alkyl hydrogens with the o-position of the ring. Thus, consideration of the /sup 13/C-/sup 13/C SSCC of a series of quite similar compounds, especially when compared to the whole set of such SSCC for other monosubstituted benzenes, shows that their relationship to the structure of the substituent R is extremely complex.

  15. Probing the possibility of a C-12/C-13 galactic abundance gradient

    International Nuclear Information System (INIS)

    Hawkins, I.

    1990-01-01

    High S/N (equal to or greater than 500) observations of interstellar CH+ with the 3.0 m telescope were performed at Lick Observatory and with the 4.0 m telescope at CTIO, of the reddened, early-type stars HD 183143, HD 24432, and HD 157038 in an effort to probe the existence of a C-12/C-13 abundance gradient in our Galaxy. Previous very high quality optical observations of interstellar CH+ toward five stars within 1 kpc of the Sun have yielded a precise weighted mean C-12/C-13 isotope ratio of 43 plus or minus 4 (1 sigma) (Hawkins, Jura, and Meyer 1985; Hawkins and Jura 1987). The isotope ratios derived toward four lines of sight in the local ISM are uniform within 12 percent. The similarity among these carbon isotope ratios determined in diffuse clouds possessing different physical conditions precludes the possibility that the CH+ molecule is suffering from isotope selective effects in these regions. The precise C-12/C-13 derivable from high quality observations of (12)CH+ and (13)CH+ provide the unique opportunity to probe the homogeneity of the ISM in a large scale and the history of nucleosynthesis in our Galaxy. Since CH+ seems to be the most sensitive probe of C-12/C-13 in the diffuse ISM, observations toward more distant stars located up to 2.5 kpc from the Sun are the best way to study the possibility of a Galactic (C-12/C-13) abundance gradient. The researcher obtained 4232 angstrom data toward all three of the stars mentioned above, 3957 angstrom data toward HD 183143 and HD 157038, and 3745 angstrom data toward HD 157038. Because of the poorer quality of the HD 24432 spectrum, and its weaker CH+ absorption lines, the satellite (13)CH+ line was not detected, and thus only a lower limit on the C-12/C-13 ratio toward this star was obtained. The results obtained from careful reduction and analysis of the data toward these stars in the Northern and Southern Hemispheres are presented

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

    Energy Technology Data Exchange (ETDEWEB)

    Stael, Giovanni Chaves [Observatorio Nacional, Rio de Janeiro, RJ (Brazil)]. E-mail: stael@on.br; Rocha, Marisa Cristina Guimaraes [Universidade do Estado do Rio de Janeiro, Nova Friburgo, RJ (Brazil). Instituto Politecnico; Menezes, Sonia Maria Cabral de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Quimica; D' Almeida, Jose Roberto Morais; Ruiz, Naira Machado da Silva [Pontificia Universidade Catolica do Rio de Janeiro, RJ (Brazil)

    2005-07-15

    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 {sup 13} C 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. (author)

  17. Skeleton labeled 13C-carbon nanoparticles for the imaging and quantification in tumor drainage lymph nodes

    Directory of Open Access Journals (Sweden)

    P Xie

    2017-07-01

    Full Text Available Ping Xie,1 Qian Xin,2 Sheng-Tao Yang,3 Tiantian He,2,4 Yuanfang Huang,2 Guangfu Zeng,2,4 Maosheng Ran,2,5 Xiaohai Tang2 1State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, Chengdu, 2Chongqing Lummy Pharmaceutical Co., Ltd, Chongqing, 3College of Chemistry & Environment Protection Engineering, Southwest University for Nationalities, 4College of Life Sciences, Sichuan Normal University, 5State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, People’s Republic of China Abstract: Carbon nanoparticles (CNPs have been widely used in tumor drainage lymph node (TDLN imaging, drug delivery, photothermal therapy, and so on. However, during the theranostic applications, the accumulation efficiency of CNPs in target organs is unknown yet, which largely hinders the extension of CNPs into clinical uses. Herein, we prepared skeleton-labeled 13C-CNPs that had identical properties to commercial CNPs suspension injection (CNSI for the imaging and quantification in TDLN. 13C-CNPs were prepared by arc discharge method, followed by homogenization with polyvinylpyrrolidone. The size distribution and morphology of 13C-CNPs were nearly the same as those of CNSI under transmission electron microscope. The hydrodynamic radii of both 13C-CNPs and CNSI were similar, too. According to X-ray photoelectron spectroscopy and infrared spectroscopy analyses, the chemical compositions and chemical states of elements were also nearly identical for both labeled and commercial forms. The skeleton labeling of 13C was reflected by the shift of G-band toward lower frequency in Raman spectra. 13C-CNPs showed competitive performance in TDLN imaging, where the three lymph nodes (popliteal lymph node, common iliac artery lymph node, and paraaortic lymph node were stained black upon the injection into the hind extremity of mice. The direct quantification of 13C-CNPs indicated that 877 µg

  18. 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)

  19. Reorientation-effect measurement of the first 2+ state in 12C: Confirmation of oblate deformation

    Directory of Open Access Journals (Sweden)

    M. Kumar Raju

    2018-02-01

    Full Text Available A Coulomb-excitation reorientation-effect measurement using the TIGRESS γ−ray spectrometer at the TRIUMF/ISAC II facility has permitted the determination of the 〈21+‖E2ˆ‖21+〉 diagonal matrix element in 12C from particle−γ coincidence data and state-of-the-art no-core shell model calculations of the nuclear polarizability. The nuclear polarizability for the ground and first-excited (21+ states in 12C have been calculated using chiral NN N4LO500 and NN+3NF350 interactions, which show convergence and agreement with photo-absorption cross-section data. Predictions show a change in the nuclear polarizability with a substantial increase between the ground state and first excited 21+ state at 4.439 MeV. The polarizability of the 21+ state is introduced into the current and previous Coulomb-excitation reorientation-effect analyses of 12C. Spectroscopic quadrupole moments of QS(21+=+0.053(44 eb and QS(21+=+0.08(3 eb are determined, respectively, yielding a weighted average of QS(21+=+0.071(25 eb, in agreement with recent ab initio calculations. The present measurement confirms that the 21+ state of 12C is oblate and emphasizes the important role played by the nuclear polarizability in Coulomb-excitation studies of light nuclei.

  20. Main component analysis of nuclear magnetic resonance /sup 1/H and /sup 13/C quantitative spectra of hydrogenation products of tars from Kansk-Achinsk Achinsk and Cheremkhovsk coals

    Energy Technology Data Exchange (ETDEWEB)

    Kushnarev, D.F.; Polonov, V.M.; Donskikh, V.I.; Rokhina, E.F.; Kalabin, G.A.

    1986-03-01

    Possibility is discussed of examining nuclear magnetic resonance /sup 1/H and /sup 13/C quantitative spectra of coal tar hydrogenation products using main component factorial analysis and applying special mathematical methods of processing experimental data. Nuclear magnetic resonance spectra of hydrogenation products of low temperature Cheremkhovsk coal carbonization tar and rapid pyrolysis Kansk-Achinsk coal tar were obtained on a WP-200SY (Bruker) spectrometer at 50.3 and 200.1 MHz, respectively. Data processing was carried out on an ODRA-1304 computer. Comparative correlation of parameters are given of tars and hydrogenation products which consist of hydrogenation of aromatic cycles and destruction of alkyl substituents, and factorial loads on structural parameters of tar hydrogenation products. 11 references.

  1. SRS-sensor 13C/12C isotops measurements for detecting Helicobacter Pylori

    Science.gov (United States)

    Grishkanich, Aleksandr; Chubchenko, Yan; Elizarov, Valentin; Zhevlakov, Aleksandr; Konopelko, Leonid

    2018-02-01

    We developed SRS-sensor 13C/12C isotops measurements detecting Helicobacter Pylori for medical diagnostics of human health. Measuring of absolute 13C/12C isotope amount ratios allows to explore the topical problems of the modern world, alcoholic beverages and tobacco, medical diagnostics of human health. SRS method is used to measure the ratio of carbon isotopes in the exhaled carbon dioxide, which is used to diagnose the human infection of Helicobacter pylori and the influence of the Helicobacter pylori bacterium on the occurrence of gastritis, gastric and duodenal ulcers. A method for the analysis of human infection with Helicobacter pylori was developed on the basis of measurements of the ratio of 13C / 12C carbon isotopes in human exhaled air with a high level of measurement accuracy. The article reviews the work in the field of provision comparability of absolute 13C/12C isotope amount ratios in the environment and food. The analysis of the technical and metrological characteristics of traditional and perspective instruments for measuring isotope ratios is presented. The provision of comparability of absolute 13C/12C isotope amount ratios is carried by gravimetrically prepared reference standards. The key features and emerging issues are discussed.

  2. Structural investigation of 18-crown-6 complexes of Tri organotin carboxylate by 1H, 13C, 19F and 119Sn nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Foladi, S.; Yousefi, M.; Mohammadpour Ammini, M. M.

    2002-01-01

    Single crystal structure determination of several 18-crown 6 complexes of orga nation derivatives reveals formation of aqua complex through hydrogen bonding to 18-crown-6, which is an important feature in their structure. In the majority of those studies, mono- and dichloro organotin have been used for complexation of them with crown ethers. In the present work, several 18-crown 6 complexes of tri organotin acetate[(C 6 H 5 ) 3 SnOCOCX 3 ] 2 , 18 C6 ], X=F, Cl, and H, have been prepared. The Lewis acidity of tin moiety in tri organotin carboxylate have been tailored by replacing hydrogen atoms of acetate group with chlorine and fluorine and influence of them in the formation of aqua complex with 18 C6 have been studied by infrared. 1 H, 13 C, 19 F and 119 Sn nuclear magnetic resonance spectroscopes. The effects of coordinating and non-coordinating solvent in status of structure in solution have been explored

  3. δ13C and 14C dating of sediments in Santa Cruz do Arari, Marajo Island (Brazil)

    International Nuclear Information System (INIS)

    Lima, Claudia More de; Pessenda, Luiz Carlos Ruiz; Rossetti, Dilce de Fatima; Rosario, Carlos da Silva; Silva, Carlos Alberto Santos da

    2007-01-01

    The eastern domain of Marajo Island, in the surroundings of Santa Cruz do Arari (Para State), is occupied by holocenic sedimentary deposits, at present covered predominantly by natural grasslands. The analysis of stable carbon isotopes in organic matter of these sediments has been applied with the objective of to evaluate the paleovegetation dynamics, the retreat or the expansion of the Amazonian Forest (located in the westerner domain) over the different types of natural grasslands in Marajo Island, during Late Quaternary. From 3.60 m to 1.80 m the δ 13 C results are around -25 (reaching value up to -29 per mille) and indicate that the organic matter of these sediments are originated from C3 plants. In the interval of 1.80 m until 0.90 m all the samples present a gradual enrichment of 13 C, indicating a higher influence of C4 plants in the vegetation cover. The intermediate δ 13 C values found in those depths (from -22 per mille to -18 per mille) indicate a mixture of C3 and C4 plants with gradual increase of areas with C4 plants. From 0.90 m to the shallow layer the δ 13 C values show a tendency to more depleted values, indicating higher influence of C3 plants in the recent and present period. The results demonstrate that the vegetation dynamics was significant in the Marajo Island from the past to the present. The chronology of these events is being determined by the 14 C dating technique and possible causes (climatic, anthropogenic and/or neotectonic) for such changes investigate. (author)

  4. C-13 NMR spectroscopy of plasma reduces interference of hypertriglyceridemia in the H-1 NMR detection of malignancy

    International Nuclear Information System (INIS)

    Fossell, E.T.; Hall, F.M.; McDonagh, J.

    1991-01-01

    The authors have previously described the application of water-suppressed proton nuclear magnetic resonance (H-1 NMR) spectroscopy of plasma for detection of malignancy. Subsequently, hypertriglyceridemia has been identified as a source of false positive results. Here is described a confirmatory, adjunctive technique -analysis of the carbon-13 (C-13) NMR spectrum of plasma- which also identifies the presence of malignancy but is not sensitive to the plasma triglyceride level. Blinded plasma samples from 480 normal donors and 208 patients scheduled for breast biopsy were analyzed by water-suppressed H-1 and C-13 NMR spectroscopy. Triglyceride levels were also measured. Among the normal donors, there were 38 individuals with hypertriglyceridemia of whom 18 had results consistent with malignancy by H-1 NMR spectroscopy. However, the C-13 technique reduced the apparent H-1 false positive rate from 7.0 to 0.6 percent. Similarly, in the breast biopsy cohort, C-13 reduced the false positive rate from 2.8 to 0.9 percent. Furthermore, the accuracy of the combined H-1/C-13 test in this blinded study was greater than 96 percent in 208 patients studied. (author). 27 refs.; 5 figs.; 4 tabs

  5. Nuclear electric power and the proliferation of nuclear weapon states

    International Nuclear Information System (INIS)

    Walske, C.

    1977-01-01

    Control and elimination of the strategic nuclear weapons held by the nuclear weapon states remains the central problem in the arms control and disarmament field. Whether the proliferation of nations with nuclear weapons can be stopped is dubious. A sovereign nation will launch a nuclear weapons program if it has the motivation and resource. Motivation depends on military and political considerations. The necessary resources are economic and technological. Conditions in some sovereign states explain this issue. A survey of commercial nuclear power programs outside the USA lists 45 countries using or planning to use nuclear reactors for power generation. There are currently 112 reactors now operating outside the United States, 117 more under construction, 60 on order, and 180 planned. The U. S. as of December 1976 has 64 operating reactors, 72 under construction, 84 on order, and 8 planned. Nuclear trade and export policies are discussed. In this article, Mr. Walske says that American industry is convinced that the need for nuclear energy abroad is more urgent than in the United States; that in the long run, the breeder reactor must be developed to enable the supply of nuclear fuel to last for centuries; and that the experience of American industry abroad has convinced it that emphasis on restrictive, denial type policies will almost certainly fail--a collapse of what has been gained through the test ban treaty and the nonproliferation treaty

  6. In vivo {sup 13}C MRS studies of carbohydrate metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Halliday, Jane

    2003-07-01

    The work described in this thesis was performed by the author, except where indicated, within the Magnetic Resonance Centre at the University of Nottingham during the period between October 1999 and October 2002. Although much is known about the major pathways of carbohydrate metabolism, there is still much to be learnt about the exact mechanisms of many of these pathways. Of particular interest is how these pathways are modified under different physiological conditions and in diseased states. {sup 13}C NMR spectroscopy provides a non-invasive means for studying carbohydrate metabolism in vivo, and the work presented within this thesis gives two such examples of this in human subjects. Natural abundance {sup 13}C NMR spectroscopy was used to measure glycogen levels in gastrocnemius muscle. The diurnal changes in response to mixed meals were measured in both type 2 diabetic subjects and age and weight matched controls. Metabolic studies were performed to complement the NMR measurements. The data obtained in these studies show the effect of the failure of muscle glucose storage upon post-prandial hyperglycaemia despite a supra-normal increase in plasma insulin in type 2 diabetes. {sup 13}C NMR spectroscopy was also used to study cerebral metabolism. Accumulation of {sup 13}C label into glutamate and glutamine following infusion of [1{sup 13}C] glucose allows the determination of the rates of the TCA cycle (F{sub TCA}) and neurotransmitter cycling (F{sub cyc}). These rates were measured in the visual cortex under control and activated conditions. The increases seen in F{sub TCA} upon activation, together with the lack of label accumulation in lactate, suggest that cerebral glucose metabolism is oxidative, even during strong activation. No conclusion can be made as to whether or not a similar increase is seen in F{sub cyc} due to the large associated errors in these values. (author)

  7. Synthesis and applications of 13C glycerol

    International Nuclear Information System (INIS)

    Stocking, E.; Khalsa, O.; Martinez, R.A.; Silks, L.A. III

    1994-01-01

    Due in part to the use of labeled glycerol for the 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 (∼53% overall yield for four steps) and are examining the feasibility of synthesizing site-specific 13 C-labeled glycerol and dihydroxyacetone (DHA) from labeled methanol and carbon dioxide. One application of 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 13 C-labeled DHA to DHAP. We are especially interested in 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 /sup 13/C NMR study of cured resorcinol-formaldehyde resins

    Energy Technology Data Exchange (ETDEWEB)

    Lippmaa, H.; Samoson, A.

    1988-08-01

    The curing process generally follows the pattern observed in the stage of prepolymer formation. Catalysts (NaOH, hexa, Mg(OCOCH/sub 3/)/sub 2/) that have no substantial influence on the isomeric composition of the resorcinol-formaldehyde prepolymers, do not affect the isomeric composition of the cured resins to any significant extent either. Isomeric composition of the cured resins depends mostly on the presence of water during the curing process, necessary for depolymerisation of the added paraformaldehyde. Curing in the melt leads to enhanced 2-substitution in the 1,3-dihydroxybenzene rings. In the /sup 13/C NMR spectra of cured powdered samples, the tendency of 5-methylresorcinol to form oligomers with a higher degree of 2-substitution than resorcinol is clearly apparent. Polycondensation process continues in the powdered resins after initial curing until complete consumption of all formaldehyde. Curing of phenol-formaldehyde resols proceeds through intermediate dimethylene ether formation.

  9. Environmental Impact Assessment for the Decommissioning of Nuclear Installations. Vol. 1-3

    International Nuclear Information System (INIS)

    Bussell, M.J.; Haigh, C.P.; O'Sullivan, P.J.; Mathieson, J.; Braeckeveldt, M.; Deconinck, J.M.; Vidaechea, S.; Beceiro, A.; Ziegenhagen, J.; Biurrun, E.; Codee, H.; Palerm, J.; Bond, A.J.; Warren, L.; Sheate, B.

    2001-06-01

    This Report presents the results of a study concerned with Environmental Impact Assessment (EIA) for the decommissioning of nuclear installations in European Union Member States and in the Applicant Countries in Central and Eastern Europe. The study, undertaken for the Environment Directorate General of the European Commission, took place between January 2000 and March 2001 under contract number B4-3040/99/136035/MAR/C2 entitled Environmental Impact Assessment for the Decommissioning of nuclear Installations. The study presents an analysis of the current situation in the European Union and in the Applicant Countries, and develops guidance for applying the relevant Directives for EIA to the specific issue of decommissioning nuclear installations although there is also scope for application to other large or controversial projects. The first part of the report (Volume 1) describes the current situation in the EU Member States and Applicant Countries. On the basis of this status, the guidance presented in Volume 2 was developed. Draft versions of these volumes were reviewed by an independent review panel and were then subjected to detailed discussion and debate at a Workshop held in Brussels in January 2001. The Workshop was attended by more than 60 representatives of the nuclear industry, nuclear regulators, public interest groups and EIA experts. Some minor changes were made following the Workshop, a record of which can be found in Volume 3. (author)

  10. 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)

  11. Foliar δ13C Showed No Altitudinal Trend in an Arid Region and Atmospheric Pressure Exerted a Negative Effect on Plant δ13C

    Directory of Open Access Journals (Sweden)

    Zixun Chen

    2017-07-01

    Full Text Available Previous studies have suggested foliar δ13C generally increases with altitude. However, some observations reported no changes or even decreased trends in foliar δ13C. We noted that all the studies in which δ13C increased with elevation were conducted in the human regions, whereas those investigations in which δ13C did not vary or decreased were conducted in areas with water stress. Thus, we proposed that the pattern of increasing δ13C with elevation is not a general one, and that δ13C may remain unchanged or decrease in plants grown in arid environments. To test the hypothesis, we sampled plants along altitude gradients on the shady and sunny slopes of Mount Tianshan characterized by arid and semiarid climates. The measurements of foliar δ13C showed no altitudinal trends for the plants grown on either of the slopes. Therefore, this study supported our hypothesis. In addition, the present study addressed the effect of atmospheric pressure on plant δ13C by accounting for the effects of temperature and precipitation on δ13C. This study found that the residual foliar δ13C increased with increasing altitude, suggesting that atmospheric pressure played a negative role in foliar δ13C.

  12. Effect of alcohol consumption on the liver detoxication capacity as measured by [13C]methacetin- and [methyl-13C]methionine-breath tests.

    Science.gov (United States)

    Wutzke, Klaus D; Forberger, Anke; Wigger, Marianne

    2008-06-01

    The aim of this study was to investigate the hepatic microsomal and mitochondrial functions by using the 13CO2-breath test in healthy subjects either before or after the consumption of red wine. Fourteen adults received [13C]methacetin and [methyl-13C]methionine together with a standardised dinner. Expired air samples were taken over 6 h. After a wash-out period, the subjects consumed 0.4 ml ethanol/kg/day together with dinner over a 10-day period. Thereafter, 13C-tracer administration was repeated under identical conditions. The 13CO2-enrichments were measured by isotope ratio mass spectrometry. The mean cumulative percentage 13C-dose recovery (CPDR) after administration of [13C]methacetin and [methyl-13C]methionine either without or with red wine consumption amounted to 38.2+/-6.3 vs. 36.3+/-6.7% (p=0.363) and 9.5+/-3.3 vs. 8.8+/-2.5% (p=0.47), respectively. Moderate alcohol consumption does not induce significant short-term changes of the microsomal and the mitochondrial functions of the human liver in healthy subjects.

  13. Ethane's 12C/13C Ratio in Titan: Implications for Methane Replenishment

    Science.gov (United States)

    Jennings, Donald E.; Nixon, C. A.; Romani, P. N.; Bjoraker, G. L.; Sada, P. V.; Lunsford, A. W.; Boyle, R. J.; Hesman, B. E.; McCabe, G. H.

    2009-01-01

    As the .main destination of carbon in the destruction of methane in the atmosphere of Titan, ethane provides information about the carbon isotopic composition of the reservoir from which methane is replenished. If the amount of methane entering the atmosphere is presently equal to the amount converted to ethane, the 12C/13C ratio in ethane should be close to the ratio in the reservoir. We have measured the 12C/13C ratio in ethane both with Cassini CIRS(exp 1) and from the ground and find that it is very close to the telluric standard and outer planet values (89), consistent with a primordial origin for the methane reservoir. The lower 12C/13C ratio measured for methane by Huygens GCMS (82.3) can be explained if the conversion of CH4 to CH3 (and C2H6) favors 12C over 13C with a carbon kinetic isotope effect of 1.08. The time required for the atmospheric methane to reach equilibrium, i.e., for replenishment to equal destruction, is approximately 5 methane atmospheric lifetimes.

  14. IMPROVED LINE DATA FOR THE SWAN SYSTEM 12C13C ISOTOPOLOGUE

    International Nuclear Information System (INIS)

    Ram, Ram S.; Brooke, James S. A.; Bernath, Peter F.; Sneden, Christopher; Lucatello, Sara

    2014-01-01

    We present new, accurate predictions for rotational line positions, excitation energies, and transition probabilities of the 12 C 13 C isotopologue Swan d 3 Π-a 3 Π system 0-0, 0–1, 0–2, 1–0, 1–1, 1–2, 2–0, 2–1, and 2–2 vibrational bands. The line positions and energy levels were predicted through new analyses of published laboratory data for the 12 C 13 C lines. Transition probabilities were derived from recent computations of transition dipole moments and related quantities. The 12 C 13 C line data were combined with similar data for 12 C 2, reported in a companion paper, and applied to produce synthetic spectra of carbon-rich metal-poor stars that have strong C 2 Swan bands. The matches between synthesized and observed spectra were used to estimate band head positions for a few of the 12 C 13 C vibrational bands and to verify that the new computed line data match observed spectra. The much weaker C 2 lines of the bright red giant Arcturus were also synthesized in the band head regions

  15. Biosynthesis of highly enriched 13C-lycopene for human metabolic studies using repeated batch tomato cell culturing with 13C-glucose

    Science.gov (United States)

    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 for three serial batches and produced increasing proportions of uniformly labeled lycopene (14.3 +/− 1.2 %, 39.6 +/− 0.5 %, and 48.9 +/− 1.5% with consistent yields (from 5.8 to 9 mg/L). An optimized 9-day-long 13C-loading and 18-day-long labeling strategy developed based on glucose utilization and lycopene yields, yielded 13C-lycopene with 93% 13C isotopic purity, and 55% of isotopomers were uniformly labeled. Furthermore, an optimized acetone and hexane extraction led to a four-fold increase in lycopene recovery from cultures compared to a standard extraction. PMID:23561155

  16. Noninvasive brain metabolism measurement using carbon-13 magnetic resonance spectroscopy ({sup 13}C-MRS); Tanso 13 jiki kyomei spectroscopy ({sup 13}C-MRS) ni yoru mushinshuteki notaisha keisoku

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, K.; Tsukada, Y. [Toshiba Corp., Tokyo (Japan)

    1998-10-10

    Carbon-13 magnetic resonance spectroscopy ({sup 13}C-MRS) and research and development efforts for brain metabolism measurement are described. Brain metabolism is a process characterized in that it not only extracts energy by disintegrating grape sugar that is the practically sole source of energy into H2O, CO2, etc., but also vigorously synthesizes amino acids that perform important functions in neural transmission, such as glutamic acid, glutamine, and {gamma}-amino acid. MRS is a technique that utilizes the magnetic resonance, which is generated when an atomic nucleus with a spin is placed in a magnetic field, for the isolation and identification of chemicals in a living body through examining the delicate difference in the magnetic resonance frequencies of the nuclei under observation. Since the signals from {sup 13}C are low in intensity as compared with those from other nuclides, a method was contrived around 1980, which observes {sup 1}H combined with {sup 13}C in grape sugar and amino acids, named the HSQC (heteronuclear single quantum coherence) method. The author et al., combining gradient magnetic pulses with HSQC, actually measure Homo sapiens brain metabolism using {sup 13}C-MRS, and now believe that the technology will be put to practical application. 7 refs., 10 figs., 1 tab.

  17. Automated 13CO2 analyzing system for the 13C breath test

    International Nuclear Information System (INIS)

    Suehiro, Makiko; Kuroda, Akira; Maeda, Masahiro; Hinaga, Kou; Watanabe, Hiroyuki.

    1987-01-01

    An automated 13 CO 2 analyzing system for the 13 C breath test was designed, built and evaluated. The system, which was designed to be controlled by a micro-computer, includes CO 2 purification, 13 CO 2 abundance measurement, data processing and data filing. This article gives the description of the whole system with flow charts. This system has proved to work well and it has become feasible to dispose of 5 to 6 CO 2 samples per hour. With such a system, the 13 C breath test will be carried out much more easily and will obtain much greater popularity. (author)

  18. State of technology assessment for life extension of electrical and I and C equipment in nuclear power plants

    International Nuclear Information System (INIS)

    DuCharme, A.R.; Boger, R.M.; Meyer, L.C.; Beament, P.R.

    1988-01-01

    As part of the IEEE Working Group 3.4 on Nuclear Plant Life Extension, an assessment is made of the current state of technology for the life extension of certain classes of electrical and IandC equipment. The classes investigated include motors, cables, emergency diesel generators, penetrations, inverters/chargers, switchgear, and reactor protection systems. The work is focussed on assessment of current or recently completed RandD efforts to resolve issues affecting life extension of the equipment. Aspects discussed include the degree of resolution of these issues, potentially affected standards, and technical aspects requiring further research. 15 refs., 2 tabs

  19. State of technology assessment for life extension of electrical and I and C equipment in nuclear power plants

    International Nuclear Information System (INIS)

    Du Charme, A.R.; Boger, R.M.; Meyer, L.C.; Beament, P.R.

    1988-01-01

    As part of the IEEE Working Group 3.4 on Nuclear Plant Life Extension, an assessment is made of the current state of technology for the life extension of certain classes of electrical and I and C equipment. The classes investigated include motors, cables, emergency diesel generators, penetrations, inverters/charges, switchgear, and reactor protection systems. The work is focussed on assessment of current or recently completed R and D efforts to resolve issues affecting life extension of the equipment. Aspects discussed include the degree of resolution of these issues, potentially affected standards, and technical aspects requiring further research

  20. Communication of nuclear data progress: No.13 (1995)

    International Nuclear Information System (INIS)

    1995-06-01

    C ommunication of nuclear data progress ( CNDP) is set up by Chinese Nuclear Data Center. This is the thirteen issue. It includes the measurements of Fe, Ni(n,xp), 58 Ni(n,α), 106,110,116 Cd(n,2n), 111 Cd(n,p), 196,198,199 Hg(n,p), 196 Hg(n,x) 195 Au reaction cross sections, Be(n,n), 58 Ni(n,α) angular distributions, and Fe, Ni(n,xp) DDCS; the theoretical calculations of P+ 11 C, d+ 11 C and n+ 63,65 Cu reaction cross sections; nuclear data evaluation method and evaluation system, the Q-value for natural element, the revision of inelastic scattering cross section of 238 U for CENDL-2.1, the evaluations of neutron monitor cross sections for 54,56∼58,Nat Fe(n,x) 51 Cr, 52,54,56 Mn and 63,65,Nat Cu(n,x) 56∼58,60 Co reactions; the benchmark testing of CENDL-2 for homogeneous fast reactor and U-fuel thermal reactor; modification and improvement of CENDL-2, progress on Chinese Evaluated Nuclear Parameter Library (CENPL) (IV); radiative loss for carbon plasma impurity; and activities and cooperation on nuclear data in China in 1994

  1. Efimov states and bound state properties in selected nuclear and molecular three-body systems

    International Nuclear Information System (INIS)

    Huber, H.S.

    1978-01-01

    The search is made among selected three-body systems for possible Efimov state behavior. In order to carry out this analysis of phenomenological potentials a new mathematical approach, the FCM (Faddeev-coordinate-momentum) technique, is developed. The analysis then proceeds through the framework of the Faddeev equations by employing the UPE (unitary pole expansion) to reduce these equations to numerically feasible form. The systems chosen for analysis are the 4 He trimer and the three-α model of 12 C. Efimov states are not found in 12 C, thus answering speculation among nuclear theorists. The 4 He trimer, on the other hand, manifests Efimov states for each potential considered and the characteristics of these states are extensively analyzed. Since Efimov states are predicted by all of the phenomenological potentials considered, these states would seem to be a realistically fundamental property of the 4 He trimer system

  2. Proceedings of the 13. Workshop on Nuclear Physics in Brazil

    International Nuclear Information System (INIS)

    1990-01-01

    Theoretical and experimental studies on nuclear structure, nuclear matter, scattering, nuclear reactions, radioactive decay, nuclear properties and nuclear models are presented. Studies on radiation protection, radiation detectors, spectroscopy and elementary particles area also presented. (M.C.K.)

  3. Proceedings of NUCLEAR 2016 the 9th annual international conference on sustainable development through nuclear research and education. Part 1/3

    International Nuclear Information System (INIS)

    Paraschiv, Irina Maria

    2016-01-01

    The Proceedings of the NUCLEAR 2016 international conference on sustainable development through nuclear research and education held at INR-Pitesti on May, 18-20, contain 81 communications presented in two plenary sessions and three sections addressing the themes of Nuclear energy, Environmental protection and Sustainable development. This section (Part 1/3) are addressing the following items: Section 1.1 Nuclear safety and severe accidents (6 papers); Section 1.2 Nuclear reactors and gen. IV (7 papers); Section 1.3 Nuclear technology and materials (29 papers); These papers are presented as abstracts in 'Nuclear 2016 - Book of Abstracts', separately processed

  4. Isotopic variations ({delta}{sup 13} C and {delta}{sup 18} O) in Siderastrea stellata (Cnidaria-Anthozoa), Itamaraca island, State of Pernambuco, Northeastern Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Valderez P.; Sial, Alcides N. [Pernambuco Univ., Recife, PE (Brazil). Dept. de Geologia. Lab. de Isotopos Estaveis; Mayeal, Elga M.; Exner, Marco Antonio [Pernambuco Univ., Recife, PE (Brazil). Dept. de Zoologia. Lab. de Macro e Megabentos

    1998-12-01

    Isotopic determinations for O and C were performed in coral skeletons collected in beach rocks from two localities (Orange and Catuama), Itamaraca Island, north littoral of the State of pernambuco, northeastern Brazil. Large variations of {delta}{sup 18} O and {delta}{sup 13} C in corals from both localities are found, the largest ones being observed at the Orange locality {delta}{sup 13} C in this locality varies from -0.8 to +1.8% PDB and {delta}{sup 1.8} O from -5.3 to -1.8% PDB, while at the Catuama locality, they vary from -1.8 to 0.1% PDB and -3.8 to -2.7% PDB, respectively. Large variations in {delta}{sup 18} O (up to 2.5%) coupled with weakly defined positive correlation between {delta}{sup 18} O and {delta}{sup 13} C, can be attributed to temperature variations as consequence of climatic perturbations. Temperature estimates, calculated from {delta}{sup 18} O values, assuming isotopic equilibrium with seawater, yield values between 24.9 deg C and 43.1 deg C at Orange, and from 28.4 deg C to 35 deg C at Catuama, all of them (expect one growth band from one sample) are high enough for the full development of the coral colony. Temperature average is 31.4 deg C at Orange, which is a little bit higher than that at Catuama, but both of them indicate thermal stress conditions. In all analyzed specimens, expect for one, at Orange, T increases was accompanied by decreasing in the organic activity, as suggested by corresponding negative {delta}{sup 13} C anomaly. Therefore, the observed bleaching is possibly related to thermal stress and the high T may be related to the El Nino-Southern Oscillation (ENSO) warning event. On the other hand, anthropogenic action at Orange, local of intense tourism throughout the year, coupled with high rate of sedimentation in the region, may contribute to the observed coral bleaching. (author)

  5. Objective and Essential Elements of a State's Nuclear Security Regime. Nuclear Security Fundamentals

    International Nuclear Information System (INIS)

    2013-01-01

    The possibility that nuclear material or other radioactive material could be used for criminal purposes or intentionally used in an unauthorized manner cannot be ruled out in the current global situation. States have responded to this risk by engaging in a collective commitment to strengthen the protection and control of such material and to respond effectively to nuclear security events. States have agreed to strengthen existing instruments and have established new international legal instruments to enhance nuclear security worldwide. Nuclear security is fundamental in the management of nuclear technologies and in applications where nuclear material or other radioactive material is used or transported. Through its nuclear security programme, the IAEA supports States to establish, maintain and sustain an effective nuclear security regime. The IAEA has adopted a comprehensive approach to nuclear security. This recognizes that an effective national nuclear security regime builds on: the implementation of relevant international legal instruments; information protection; physical protection; material accounting and control; detection of and response to trafficking in such material; national response plans; and contingency measures. With its Nuclear Security Series, the IAEA aims to assist States in implementing and sustaining such a regime in a coherent and integrated manner. The IAEA Nuclear Security Series comprises: Nuclear Security Fundamentals, which include the objective and essential elements of a State's nuclear security regime; Recommendations; Implementing Guides; and Technical Guidance. Each State carries the full responsibility for nuclear security. Specifically, each State has the responsibility to provide for the security of nuclear material and other radioactive material and their associated facilities and activities; to ensure the security of such material in use, storage, or in transport; to combat illicit trafficking and the inadvertent movement of

  6. CP/MAS 13C NMR characterization of the isomeric states and intermolecular packing in tris(8-hydroxyquinoline) aluminum(III) (Alq3).

    Science.gov (United States)

    Kaji, Hironori; Kusaka, Yasunari; Onoyama, Goro; Horii, Fumitaka

    2006-04-05

    The isomeric states and intermolecular packing of tris(8-hydroxyquinoline) aluminum(III) (Alq(3)) in the alpha-, gamma-, and delta-crystalline forms and in the amorphous state, which are important for understanding the light-emitting and electron-transport properties, have been analyzed by CP/MAS (13)C NMR. This simple NMR experiment shows that the isomeric state of alpha- and amorphous Alq(3) is meridional, whereas that of gamma- and delta-Alq(3) is facial. In the amorphous Alq(3), the inclusion of facial isomers has been under debate. Our experiments show that meridional isomers are dominant in the amorphous Alq(3), although the existence of facial isomers cannot be completely denied. The local structure of amorphous Alq(3) is similar to that of alpha-Alq(3) and is significantly different from those of gamma- and delta-Alq(3). Among these Alq(3) samples, the effect of intermolecular interaction is not found only for gamma-Alq(3). This finding can explain the good solvent solubility of gamma-Alq(3), compared with the other crystalline forms. It is also shown that the structures are locally disordered not only for amorphous Alq(3) but also for alpha-Alq(3), although clear X-ray diffraction peaks are observed for alpha-Alq(3). In contrast, the local structures of gamma- and delta-Alq(3) are well defined. A clear relation is found between the spectral patterns of CP/MAS (13)C NMR and the fluorescence wavelengths; the samples, which consist of facial isomers, show blue-shifted fluorescence compared with those of meridionals.

  7. 13C-NMR assignment, structure, and dynamics of deoxyoligonucleotides

    International Nuclear Information System (INIS)

    Zanatta, N.; Borer, P.N.; Levy, G.C.

    1986-01-01

    The unique spectral properties of 13 C-NMR for studying nucleic acids and some of the important features of 13 C-NMR in oligonucleotide studies are demostrated. The main difficulty in studying oligonucleotides by 13 C-NMR and recent improvements in NMR instrumentation and advances in oligonucleotide synthesis are presented. The high resolution 13 C-NMR spectra, T 1 relaxation times and NOEs were measured for duplex of the self-complementary oligo-DNAs: d(CG) 3 and d(GGTATACC) are studied. The target of this study is to developed a systematic 13 C-NMR spectral assignment and to investigate the structure and dynamics of these two sequences by this techniques. (M.J.C.) [pt

  8. Synthesis of {sup 14}C-labeled levamisole and {sup 13}C-labeled tetramisole

    Energy Technology Data Exchange (ETDEWEB)

    Feil, V.J. [US Department of Agriculture, Agricultural Research Service, Biosciences Research Lab., Fargo, ND (United States)

    1996-12-01

    The syntheses of {sup 14}C-ring labeled levamisole ([-]-2,3,5,6-tetrahydro-6-phenyl [{sup 14}C]-UL imidazo[2,1-b]thiazole) from acetophenone-ring-UL-{sup 14}C in 5 steps plus resolution with a 7.5% overall yield, and {sup 13}C{sub 6}-ring labeled tetramisole ([{+-}]-2,3,5,6-tetrahydro-6-phenyl [{sup 13}C{sub 6}]imidazo[2,1-b]thiazole) from benzene-{sup 13}C{sub 6} in 6 steps with a 9.0% overall yield are described. (author).

  9. Transport of C-13-labelled linoleic and C-13-labelled caprylic acid in rat plasma after administration of specific structured triacylglycerols

    DEFF Research Database (Denmark)

    Vistisen, Bodil; Høy, Carl-Erik

    2004-01-01

    the transport of dietary C-13-labelled fatty acids in rat plasma to compare the chylomicron fatty acid metabolism after administration of specific structured, long chain and medium chain triacylglycerols. Rats were fed ML*M, M*LM*, L*L*L* or M*M*M* (L=linoleic acid, 18:2n-6, M=caprylic acid, 8:0, * = C-13......-labelled fatty acid) by gavage. A maximum transport of 0.5% of the administered C-13-labelled 18:2n-6 was observed in 1mL rat plasma both after administration of L*L*L* and ML*M, while approximately 0.04% of the administered C-13-labelled 8:0 was detected in 1mL plasma following administration of M......*M*M* or M*LM*. After L*L*L* administration C-13-labelled 20:4n-6 was observed in plasma, probably formed by elongation and desaturation of 18:2n-6 in the enterocyte or liver cells. Furthermore, C-13-labelled 16:0, 48:0, 18: 1n-9 and 20:4n-6 were observed in plasma of rats fed M*M*M* and M*LM* due...

  10. NMR 1H,13C, 15N backbone and 13C side chain resonance assignment of the G12C mutant of human K-Ras bound to GDP.

    Science.gov (United States)

    Sharma, Alok K; Lee, Seung-Joo; Rigby, Alan C; Townson, Sharon A

    2018-05-02

    K-Ras is a key driver of oncogenesis, accounting for approximately 80% of Ras-driven human cancers. The small GTPase cycles between an inactive, GDP-bound and an active, GTP-bound state, regulated by guanine nucleotide exchange factors and GTPase activating proteins, respectively. Activated K-Ras regulates cell proliferation, differentiation and survival by signaling through several effector pathways, including Raf-MAPK. Oncogenic mutations that impair the GTPase activity of K-Ras result in a hyperactivated state, leading to uncontrolled cellular proliferation and tumorogenesis. A cysteine mutation at glycine 12 is commonly found in K-Ras associated cancers, and has become a recent focus for therapeutic intervention. We report here 1 H N, 15 N, and 13 C resonance assignments for the 19.3 kDa (aa 1-169) human K-Ras protein harboring an oncogenic G12C mutation in the GDP-bound form (K-RAS G12C-GDP ), using heteronuclear, multidimensional NMR spectroscopy. Backbone 1 H- 15 N correlations have been assigned for all non-proline residues, except for the first methionine residue.

  11. Study of α-monosubstituted methyl acetates by C-13 and H-1 Nuclear Magnetic resonance

    International Nuclear Information System (INIS)

    Silva, E.L.

    1987-01-01

    The substituents effects on the methylene and carbonyl carbons chemical shifts of some α-monosubstituted methyl acetates Z-CH 2 -COOMe(Z=H,Cl,Br,I,OME,SMe,NMe 2 and Me) is studied. Some data of Carbon 13 NMr in the light of the substituents empirical and electronic effects are shown. Solvent and concentration effects on the hydrogen-1 chemical shifts of methyl acetate, bromoacetate and Iodoacetate were interpreted in the light of the Cα-C(O)-bond rotational isomerism. (M.J.C.) [pt

  12. Site-selective 13C labeling of proteins using erythrose

    International Nuclear Information System (INIS)

    Weininger, Ulrich

    2017-01-01

    NMR-spectroscopy enables unique experimental studies on protein dynamics at atomic resolution. In order to obtain a full atom view on protein dynamics, and to study specific local processes like ring-flips, proton-transfer, or tautomerization, one has to perform studies on amino-acid side chains. A key requirement for these studies is site-selective labeling with 13 C and/or 1 H, which is achieved in the most general way by using site-selectively 13 C-enriched glucose (1- and 2- 13 C) as the carbon source in bacterial expression systems. Using this strategy, multiple sites in side chains, including aromatics, become site-selectively labeled and suitable for relaxation studies. Here we systematically investigate the use of site-selectively 13 C-enriched erythrose (1-, 2-, 3- and 4- 13 C) as a suitable precursor for 13 C labeled aromatic side chains. We quantify 13 C incorporation in nearly all sites in all 20 amino acids and compare the results to glucose based labeling. In general the erythrose approach results in more selective labeling. While there is only a minor gain for phenylalanine and tyrosine side-chains, the 13 C incorporation level for tryptophan is at least doubled. Additionally, the Phe ζ and Trp η2 positions become labeled. In the aliphatic side chains, labeling using erythrose yields isolated 13 C labels for certain positions, like Ile β and His β, making these sites suitable for dynamics studies. Using erythrose instead of glucose as a source for site-selective 13 C labeling enables unique or superior labeling for certain positions and is thereby expanding the toolbox for customized isotope labeling of amino-acid side-chains.

  13. Pion elastic scattering from polarized 13C in the energy region of the P33 resonance

    International Nuclear Information System (INIS)

    Yifen, Yen

    1992-08-01

    Asymmetries (A y ) and differential cross sections (dσ/dΩ) were measured for π + and π - elastic scattering using polarized and unpolarized 13 C targets. The experiment was done at the Los Alamos Meson Physics Facility with the pion beam from the Low Energy Pion channel. The scattered pions were detected with the Large Acceptance Spectrometer. The 13 C nuclei in 13 C-enriched 1-butanol were polarized by the dynamic nuclear polarilization method. Angular distributions of both A y and dσ/dΩ were measured below the P 33 resonance at the incident energy of 130 MeV for π + and π - , and above the resonance at 223 MeV for π + and at 226 MeV for π - . In addition, A y and dσ/dΩ were measured in a range of momentum transfers, 1.75 ≤ q ≤ 2.05 fm - , at several energies. At 130 MeV, the values of A y are significantly different from zero for π - scattering. For π + at 130 MeV and for both π - and π + at all other energies, the A y are mostly consistent with zero. Theoretical analyses were done using different nuclear structure models. The data were not reproduced by the presently available nuclear wave functions. It was found that the asymmetry is strongly sensitive to the quadrupole spin flip part of the transition. The data of this thesis complement measurements of the magnetic form factor from electron scattering. In attempts to fit both the asymmetry and the magnetic form factor, it was found that the pion asymmetry data are not reproduced by the wavefunctions which fit the magnetic form factor at low momentum transfers

  14. Nuclear development in the United States

    International Nuclear Information System (INIS)

    Brewer, S.

    1983-01-01

    The history of the nuclear development in the United States has been one of international cooperation relations so far. The United States is to offer the technical information on atomic energy utilization to foreign countries in exchange for the guarantee that they never attempt to have or develop nuclear weapons. Actually, the United States has supplied the technologies on nuclear fuel cycle and other related fields to enable other countries to achieve economical and social progress. The Department of Energy clarified the public promise of the United States regarding the idea of international energy community. The ratio of nuclear power generation to total electric power supply in the United States exceeded 12%, and will exceed 20% by 1990. Since 1978, new nuclear power station has not been ordered, and some of the contracted power stations were canceled. The atomic energy industry in the United States prospered at the beginning of 1970s, but lost the spirit now, mainly due to the institutional problems rather than the technical ones. As the policy of the government to eliminate the obstacles, the improvement of the procedure for the permission and approval, the establishment of waste disposal capability, the verification of fast breeder reactor technology and the promotion of commercial fuel reprocessing were proposed. The re-establishment of the United States as the reliable supplier of atomic energy service is the final aim. (Kako, I.)

  15. Properties of K,Rb-intercalated C60 encapsulated inside carbon nanotubes called peapods derived from nuclear magnetic resonance

    KAUST Repository

    Mahfouz, Remi; Bouhrara, M.; Kim, Y.; Wå gberg, T.; Goze-Bac, C.; Abou-Hamad, Edy

    2015-01-01

    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

  16. Communication of nuclear data progress: No.13 (1995)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-06-01

    {sup C}ommunication of nuclear data progress{sup (}CNDP) is set up by Chinese Nuclear Data Center. This is the thirteen issue. It includes the measurements of Fe, Ni(n,xp), {sup 58}Ni(n,{alpha}), {sup 106,110,116}Cd(n,2n), {sup 111}Cd(n,p), {sup 196,198,199}Hg(n,p), {sup 196}Hg(n,x){sup 195}Au reaction cross sections, Be(n,n), {sup 58}Ni(n,{alpha}) angular distributions, and Fe, Ni(n,xp) DDCS; the theoretical calculations of P+{sup 11}C, d+{sup 11}C and n+{sup 63,65}Cu reaction cross sections; nuclear data evaluation method and evaluation system, the Q-value for natural element, the revision of inelastic scattering cross section of {sup 238}U for CENDL-2.1, the evaluations of neutron monitor cross sections for {sup 54,56{approx}58,Nat}Fe(n,x){sup 51}Cr, {sup 52,54,56}Mn and {sup 63,65,Nat}Cu(n,x){sup 56{approx}58,60}Co reactions; the benchmark testing of CENDL-2 for homogeneous fast reactor and U-fuel thermal reactor; modification and improvement of CENDL-2, progress on Chinese Evaluated Nuclear Parameter Library (CENPL) (IV); radiative loss for carbon plasma impurity; and activities and cooperation on nuclear data in China in 1994.

  17. 14C emission from Swedish nuclear power plants and its effect on the 14C levels in the environment

    International Nuclear Information System (INIS)

    Stenstroem, K.; Erlandsson, Bengt; Hellborg, R.; Kiisk, M.; Persson, Per; Mattsson, Soeren; Thornberg, C.; Skog, G.

    2000-02-01

    The radionuclide 14 C is produced in all types of nuclear reactors mainly by neutron induced reactions in oxygen ( 17 O), nitrogen ( 14 N) and carbon ( 13 C). Part of the 14 C created is continuously released during normal operation as airborne effluents in various chemical forms (such as CO 2 , CO and hydrocarbons) to the surroundings. Because of the biological importance of carbon and the long physical half-life of 14 C, it is of interest to measure the releases and their incorporation into living material. The 14 C activity concentrations in annual tree rings and air around two Swedish nuclear power plants (Barsebaeck and Forsmark) as well as the background 14 C activity levels from two reference sites in southern Sweden during 1973-1996 are presented in this report. In order to verify the reliability of the method some investigations have been conducted at two foreign nuclear sites, Sellafield fuel reprocessing plant in England, and Pickering nuclear generating station in Canada, where the releases of 14 C are known to be substantial. Furthermore, results from some measurements in the vicinity of Paldiski submarine training centre in Estonia are presented. The results of the 14 C measurements of air, vegetation and annual tree rings around the two Swedish nuclear power plants show very low enhancements of 14 C, if at all above the uncertainty of the measurements. Even if the accuracy of the measurements of the annual tree rings is rather good (1-2%) the contribution of 14 C from the reactors to the environment is so small that it is difficult to separate it from the prevailing background levels of 14 C . This is the case for all sampling procedures: in air and vegetation as well as in annual tree rings. Only on a few occasions an actual increase is observed. However, although the calculations suffer from rather large uncertainties, the calculated release rate from Barsebaeck is in fair agreement with reported release data. The results of this investigation show

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

    Science.gov (United States)

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

    1990-07-01

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

  19. 13C ENDOR Spectroscopy of Lipoxygenase-Substrate Complexes Reveals the Structural Basis for C-H Activation by Tunneling.

    Science.gov (United States)

    Horitani, Masaki; Offenbacher, Adam R; Carr, Cody A Marcus; Yu, Tao; Hoeke, Veronika; Cutsail, George E; Hammes-Schiffer, Sharon; Klinman, Judith P; Hoffman, Brian M

    2017-02-08

    In enzymatic C-H activation by hydrogen tunneling, reduced barrier width is important for efficient hydrogen wave function overlap during catalysis. For native enzymes displaying nonadiabatic tunneling, the dominant reactive hydrogen donor-acceptor distance (DAD) is typically ca. 2.7 Å, considerably shorter than normal van der Waals distances. Without a ground state substrate-bound structure for the prototypical nonadiabatic tunneling system, soybean lipoxygenase (SLO), it has remained unclear whether the requisite close tunneling distance occurs through an unusual ground state active site arrangement or by thermally sampling conformational substates. Herein, we introduce Mn 2+ as a spin-probe surrogate for the SLO Fe ion; X-ray diffraction shows Mn-SLO is structurally faithful to the native enzyme. 13 C ENDOR then reveals the locations of 13 C10 and reactive 13 C11 of linoleic acid relative to the metal; 1 H ENDOR and molecular dynamics simulations of the fully solvated SLO model using ENDOR-derived restraints give additional metrical information. The resulting three-dimensional representation of the SLO active site ground state contains a reactive (a) conformer with hydrogen DAD of ∼3.1 Å, approximately van der Waals contact, plus an inactive (b) conformer with even longer DAD, establishing that stochastic conformational sampling is required to achieve reactive tunneling geometries. Tunneling-impaired SLO variants show increased DADs and variations in substrate positioning and rigidity, confirming previous kinetic and theoretical predictions of such behavior. Overall, this investigation highlights the (i) predictive power of nonadiabatic quantum treatments of proton-coupled electron transfer in SLO and (ii) sensitivity of ENDOR probes to test, detect, and corroborate kinetically predicted trends in active site reactivity and to reveal unexpected features of active site architecture.

  20. 13C and 31P NMR study of gluconeogenesis: utilization of 13C-labeled substrates by perfused liver from streptozotocin-diabetic and untreated rats

    International Nuclear Information System (INIS)

    Cohen, S.M.

    1987-01-01

    The metabolism of 13 C-labeled substrates was followed by 13 C and 31 P NMR in perfused liver from the streptozotocin-treated rat model of insulin-dependent diabetes. Comparison was made with perfused liver from untreated littermates, fasted either 24 or 12 h. The major routes of pyruvate metabolism were followed by a 13 C NMR approach that provided for the determination of the metabolic fate of several substances simultaneously. The rate of gluconeogenesis was 2-4-fold greater and β-hydroxybutyrate production was 50% greater in liver from the chronically diabetic rats as compared with the control groups. Large differences in the distribution of 13 C label in hepatic alanine were measured between diabetic and control groups. The biosyntheses of 13 C-labeled glutathione and N-carbamoylaspartate were monitored in time-resolved 13 C NMR spectra of perfused liver. Assignments for the resonances of glutathione and N-carbamoylaspartate were made with the aid of 13 C NMR studies of perchloric acid extracts of the freeze-clamped livers. 13 C NMR spectroscopy of the perfusates provided a convenient, rapid assay of the rate of oxidation of [2- 13 C]ethanol, the hepatic output of [2- 13 ]acetaldehyde, and the accumulation of [2- 13 C]acetate in the perfusate. By 31 P NMR spectroscopy, carbamoyl phosphate was measured in all diabetic livers and an unusual P,P'-diesterified pyrophosphate was observed in one-fourth of the diabetic livers examined. Neither of these phosphorylated metabolites was detected in control liver. Both 13 C and 31 P NMR were useful in defining changes in hepatic metabolism in experimental diabetes

  1. ASN report abstracts on the state of Nuclear Safety and Radiation Protection in France in 2008. ASN annual report 2008

    International Nuclear Information System (INIS)

    2009-01-01

    ASN is an independent administrative authority tasked, on behalf of the state, with regulating nuclear safety and radiation protection in order to protect workers, patients and the environment from the hazards involved in nuclear activities. It also contributes to informing the public. ASN, run by a five-member commission, regulates the whole of the sector, acting in a completely impartial manner. The ASN Commission presents its report on the state of nuclear safety and radiation protection in France in 2008. Contents: A - Introduction: The year 2008. B - Key topics: 1. ASN actions to promote greater transparency; 2. EDF nuclear power plant ageing and operating life: the conditions for continued operation; 3. The prevention of malicious acts; 4. ASN regulation of the radiotherapy sector; 5. Regulating and monitoring the construction of the Flamanville 3 EPR reactor; 6. ASN's international nuclear safety responsibilities; 7. The new nuclear countries; 8. Decommissioning of basic nuclear installations and the low-level, long-lived waste disposal project. C - Overview: 1 - Nuclear activities: ionising radiations and health risks; 2 - Principles and stakeholders in the regulation of nuclear safety and radiation protection; 3 - Regulation; 4 - Regulation of nuclear activities and exposure to ionising radiations; 5 - Environmental protection; 6 - Public information and transparency; 7 - International relations; 8 - Radiological emergencies; 9 - Medical uses of ionising radiations; 10 - Industrial and research activities; 11 - Transport of radioactive materials; 12 - EDF nuclear power plants; 13 - Nuclear fuel cycle installations; 14 - Nuclear research facilities and various nuclear installations; 15 - Safe decommissioning of basic nuclear installations; 16 - Radioactive waste and polluted sites. D - Appendices: List of basic nuclear installations; ASN decisions and opinions published in 2008 in its Official Bulletin; Acronyms, abbreviations and names

  2. Comparison of 13C Nuclear Magnetic Resonance and Fourier Transform Infrared spectroscopy for estimating humification and aromatization of soil organic matter

    Science.gov (United States)

    Rogers, K.; Cooper, W. T.; Hodgkins, S. B.; Verbeke, B. A.; Chanton, J.

    2017-12-01

    Solid state direct polarization 13C NMR spectroscopy (DP-NMR) is generally considered the most quantitatively reliable method for soil organic matter (SOM) characterization, including determination of the relative abundances of carbon functional groups. These functional abundances can then be used to calculate important soil parameters such as degree of humification and extent of aromaticity that reveal differences in reactivity or compositional changes along gradients (e.g. thaw chronosequence in permafrost). Unfortunately, the 13C NMR DP-NMR experiment is time-consuming, with a single sample often requiring over 24 hours of instrument time. Alternatively, solid state cross polarization 13C NMR (CP-NMR) can circumvent this problem, reducing analyses times to 4-6 hours but with some loss of quantitative reliability. Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) is a quick and relatively inexpensive method for characterizing solid materials, and has been suggested as an alternative to NMR for analysis of soil organic matter and determination of humification (HI) and aromatization (AI) indices. However, the quantitative reliability of ATR-FTIR for SOM analyses has never been verified, nor have any ATR-FTIR data been compared to similar measurements by NMR. In this work we focused on FTIR vibrational bands that correspond to the three functional groups used to calculate HI and AI values: carbohydrates (1030 cm-1), aromatics (1510, 1630 cm-1), and aliphatics (2850, 2920 cm-1). Data from ATR-FTIR measurements were compared to analogous quantitation by DP- and CP-NMR using peat samples from Sweden, Minnesota, and North Carolina. DP- and CP-NMR correlate very strongly, although the correlations are not always 1:1. Direct comparison of relative abundances of the three functional groups determined by NMR and ATR-FTIR yielded satisfactory results for carbohydrates (r2= 0.78) and aliphatics (r2=0.58), but less so for aromatics (r2= 0

  3. The 13C bicarbonate method

    DEFF Research Database (Denmark)

    Junghans, Peter; Larsson, Caroline; Jensen, Rasmus Bovbjerg

    2015-01-01

    2 production calculated by the (13)C-BM, RaCO2((13)C) is compared to the result from the indirect calorimetry, RCO2(IC). In an interspecies comparison (dog, goat, horse, cattle, children, adult human; body mass ranging from 15 to 350 kg, resting and fasting conditions) we found an excellent...

  4. State of the art and prospects of nuclear power development

    International Nuclear Information System (INIS)

    Egorov, Yu.V.; Glushenkova, S.Z.

    1984-01-01

    State of the art and prospects of nuclear power development abroad except the COMECON countries and Yugoslavia, are considered. Both average electric power of power units and load factor (LF) are shown to increase. Data on both the total generating capacity and nuclear power generation in certain countries are given. The number of commissioned NPPs in the USA decreases but terms of their construction and licensing are reduced, program of fast breeder reactor construction is being realized, prohibition of nuclear fuel reprocessing in cancelled. France came to the second place in the world as regards the operating NPPs. The nuclear power generation in Japan makes up 13% of the total generating capacity in the country. The LF of the Japan NPPs with BWR and PWR in 1982 made up 70.7 and 69.8%, respectively. A higher reliability of NPPs, decrease in the time for periodical inspections and prolongation of the operating cycle have promoted an increase in the LF

  5. State fund of decommissioning of nuclear installations and handling of spent nuclear fuels and nuclear wastes (Slovak Republic)

    International Nuclear Information System (INIS)

    Kozma, Milos

    2006-01-01

    State Fund for Decommissioning of Nuclear Installations and Handling of Spent Nuclear Fuels and Nuclear Wastes was established by the Act 254/1994 of the National Council of the Slovak Republic as a special-purpose fund which concentrates financial resources intended for decommissioning of nuclear installations and for handling of spent nuclear fuels and radioactive wastes. The Act was amended in 2000, 2001 and 2002. The Fund is legal entity and independent from operator of nuclear installations Slovak Power Facilities Inc. The Fund is headed by Director, who is appointed and recalled by Minister of Economy of the Slovak Republic. Sources of the Fund are generated from: a) contributions by nuclear installation operators; b) penalties imposed by Nuclear Regulatory Authority of the Slovak Republic upon natural persons and legal entities pursuant to separate regulation; c) bank credits; d) interest on Fund deposits in banks; e) grants from State Budget; f) other sources as provided by special regulation. Fund resources may be used for the following purposes: a) decommissioning of nuclear installations; b) handling of spent nuclear fuels and radioactive wastes after the termination of nuclear installation operation; c) handling of radioactive wastes whose originator is not known, including occasionally seized radioactive wastes and radioactive materials stemming from criminal activities whose originator is not known, as confirmed by Police Corps investigator or Ministry of Health of the Slovak Republic; d) purchase of land for the establishment of nuclear fuel and nuclear waste repositories; e) research and development in the areas of decommissioning of nuclear installations and handling of nuclear fuels and radioactive wastes after the termination of the operation of nuclear installations; f) selection of localities, geological survey, preparation, design, construction, commissioning, operation and closure of repositories of spent nuclear fuels and radioactive wastes

  6. Properties of SYNROC C nuclear-waste form: a state-of-the-art review

    International Nuclear Information System (INIS)

    Oversby, V.M.

    1982-09-01

    SYNROC C is a titanate ceramic waste form designed to contain the waste generated by the reprocessing of commercial nuclear reactor fuel. The properties of SYNROC C are described with particular emphasis on the distribution of chemical elements in SYNROC, the fabrication of good quality specimens, and the chemical durability of SYNROC. Data obtained from testing of natural mineral analogues of SYNROC minerals are briefly discussed. The information available on radiation effects in SYNROC in relation to structural alteration and changes in chemical durability are summarized. 26 references, 2 figures, 18 tables

  7. The 12C/ 13C isotopic ratio in Titan hydrocarbons from Cassini/CIRS infrared spectra

    Science.gov (United States)

    Nixon, C. A.; Achterberg, R. K.; Vinatier, S.; Bézard, B.; Coustenis, A.; Irwin, P. G. J.; Teanby, N. A.; de Kok, R.; Romani, P. N.; Jennings, D. E.; Bjoraker, G. L.; Flasar, F. M.

    2008-06-01

    We have analyzed infrared spectra of Titan recorded by the Cassini Composite Infrared Spectrometer (CIRS) to measure the isotopic ratio 12C/ 13C in each of three chemical species in Titan's stratosphere: CH 4, C 2H 2 and C 2H 6. This is the first measurement of 12C/ 13C in any C 2 molecule on Titan, and the first measurement of 12CH 4/ 13CH 4 (non-deuterated) on Titan by remote sensing. Our spectra cover five widely-spaced latitudes, 65° S to 71° N and we have searched for both latitude variability of 12C/ 13C within a given species, and also for differences between the 12C/ 13C in the three gases. For CH 4 alone, we find C12/C13=76.6±2.7 (1- σ), essentially in agreement with the 12CH 4/ 13CH 4 measured by the Huygens Gas Chromatograph/Mass Spectrometer instrument (GCMS) [Niemann, H.B., and 17 colleagues, 2005. Nature 438, 779-784]: 82.3±1.0, and also with measured values in H 13CN and 13CH 3D by CIRS at lower precision [Bézard, B., Nixon, C., Kleiner, I., Jennings, D., 2007. Icarus 191, 397-400; Vinatier, S., Bézard, B., Nixon, C., 2007. Icarus 191, 712-721]. For the C 2 species, we find C12/C13=84.8±3.2 in C 2H 2 and 89.8±7.3 in C 2H 6, a possible trend of increasingly value with molecular mass, although these values are both compatible with the Huygens GCMS value to within error bars. There are no convincing trends in latitude. Combining all fifteen measurements, we obtain a value of C12/C13=80.8±2.0, also compatible with GCMS. Therefore, the evidence is mounting that 12C/ 13C is some 8% lower on Titan than on the Earth (88.9, inorganic standard), and lower than typical for the outer planets ( 88±7 [Sada, P.V., McCabe, G.H., Bjoraker, G.L., Jennings, D.E., Reuter, D.C., 1996. Astrophys. J. 472, 903-907]). There is no current model for this enrichment, and we discuss several mechanisms that may be at work.

  8. CACA-TOCSY with alternate {sup 13}C-{sup 12}C labeling: a {sup 13}C{sup {alpha}} direct detection experiment for mainchain resonance assignment, dihedral angle information, and amino acid type identification

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Koh [National Institute of Advanced Industrial Science and Technology (AIST), Biomedicinal Information Research Center (BIRC) (Japan); Frueh, Dominique P.; Sun, Zhen-Yu J.; Hiller, Sebastian; Wagner, Gerhard, E-mail: gerhard_wagner@hms.harvard.ed [Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology (United States)

    2010-05-15

    We present a {sup 13}C direct detection CACA-TOCSY experiment for samples with alternate {sup 13}C-{sup 12}C labeling. It provides inter-residue correlations between {sup 13}C{sup {alpha}} resonances of residue i and adjacent C{sup {alpha}s} at positions i - 1 and i + 1. Furthermore, longer mixing times yield correlations to C{sup {alpha}} nuclei separated by more than one residue. The experiment also provides C{sup {alpha}}-to-side chain correlations, some amino acid type identifications and estimates for {psi} dihedral angles. The power of the experiment derives from the alternate {sup 13}C-{sup 12}C labeling with [1,3-{sup 13}C] glycerol or [2-{sup 13}C] glycerol, which allows utilizing the small scalar {sup 3}J{sub CC} couplings that are masked by strong {sup 1}J{sub CC} couplings in uniformly {sup 13}C labeled samples.

  9. Excited states of 12C above the alpha-decay threshold

    International Nuclear Information System (INIS)

    Freer, M; Ashwood, N I; Barr, M; Curtis, N; Malcolm, J D; Wheldon, C; Ziman, V A; Almaraz-Calderon, S; Aprahamian, A; Bucher, B; Couder, M; Fang, X; Jung, F; Lu, W; Roberts, A; Tan, W P; Copp, P; Lesher, S

    2011-01-01

    The excitation energy spectrum of 12 C is important for both structural and astrophysical reasons; here we present evidence for a new state in 12 C. The two reactions 12 C( 4 He, 4 He+ 4 He+ 4 He) 4 He and 9 Be( 4 He, 4 He+ 4 He+ 4 He)n were measured using an array of four double sided strip detectors. Excited states in 12 C were reconstructed filtered by the condition that the alpha-decay proceeded via the 8 Be ground-state. In both measurements evidence was found for a new state at 13.3(0.2) MeV with a width 1.7(0.2) MeV. Angular correlation measurements from the 12 C( 4 He, 4 He+ 4 He+ 4 He) 4 He reaction indicates that the state may have J π = 4 + .

  10. 13C separation by IRMPD of halogenated difluoromethanes

    International Nuclear Information System (INIS)

    Ma Peihua; Chen Guancheng; Wu Bin; Liu Julin; Jing Yan; Chu Minxiong; Arai, Shigeyoshi.

    1995-01-01

    Isotopically-selective consecutive two-stage infrared multiphoton dissociation (IRMPD) of halogenated difluoromethanes in the presence of scavengers produces carbon-13 over 95 %. The reaction mechanism for the IRMPD of mixture of CHClF 2 and HI can be explained by a series of first-order dissociation reactions and followed radical-scavenger reactions occurred in a continuous irradiation procedure. Furthermore, 13 C enrichment at laboratory scaling-up level by the 13 C selective IRMPD of CHClF 2 /Br 2 mixture has been investigated in a flow reactor. The 13 C production rates, 13 C atomic fractions in the CBr 2 F 2 products and 13 C depletions in the CHClF 2 reactants at different flow rates and laser repetition frequencies were examined to optimize the parameters suitable for large-scale production of carbon isotope. The data obtained from the flow tests demonstrated a 40 mg h -1 production rate for CB 2 F 2 at 65 % carbon-13 by using a 40 W (4J, 10 Hz) laser beam focused with a lens of focal length 120 cm. If a reliable TEA CO 2 laser can be operated with 100 W (10 J, 10 Hz) output, the production rate of CBr 2 F 2 for carbon-13 at 60 % can attain 200 mg h -1 . The measurements of spatial profile of focused laser beam imply a 2 g h -1 production rate for the 60 % carbon-13 product for an incident power of 200 W (20 J, 10 Hz). (author)

  11. Position-specific 13C distributions within propane from experiments and natural gas samples

    Science.gov (United States)

    Piasecki, Alison; Sessions, Alex L.; Lawson, Michael; Ferreira, A.A.; Santos Neto, E. V.; Ellis, Geoffrey S.; Lewan, Michael; Eilers, J.M.

    2018-01-01

    Site-specific carbon isotope measurements of organic compounds potentially recover information that is lost in a conventional, ‘bulk’ isotopic analysis. Such measurements are useful because isotopically fractionating processes may have distinct effects at different molecular sites, and thermodynamically equilibrated populations of molecules tend to concentrate heavy isotopes in one molecular site versus another. Most recent studies of site-specific 13C in organics use specialized Nuclear Magnetic Resonance (NMR) techniques or complex chemical degradations prior to mass spectrometric measurements. Herein we present the first application of a new mass spectrometric technique that reconstructs the site-specific carbon isotope composition of propane based on measurements of the 13C/12C ratios of two or more fragment ions that sample different proportions of the terminal and central carbon sites. We apply this method to propane from laboratory experiments and natural gas samples to explore the relationships between site-specific carbon isotope composition, full-molecular δ13C, thermal maturity, and variation in organic matter precursors. Our goal is to advance the understanding of the sources and histories of short-chain alkanes within geologic systems. Our findings suggest that propane varies in its site-specific carbon isotope structure, which is correlated with increasing thermal maturity, first increasing in terminal position δ13C and then increasing in both center and terminal position δ13C. This pattern is observed in both experimental and natural samples, and is plausibly explained by a combination of site-specific, temperature-dependent isotope effects associated with conversion of different precursor molecules (kerogen, bitumen, and/or oil) to propane, differences in site-specific isotopic contents of those precursors, and possibly distillation of reactive components of those precursors with increasing maturity. We hypothesize that the largest changes in

  12. Position-specific 13C distributions within propane from experiments and natural gas samples

    Science.gov (United States)

    Piasecki, Alison; Sessions, Alex; Lawson, Michael; Ferreira, A. A.; Santos Neto, E. V.; Ellis, Geoffrey S.; Lewan, Michael D.; Eiler, John M.

    2018-01-01

    Site-specific carbon isotope measurements of organic compounds potentially recover information that is lost in a conventional, 'bulk' isotopic analysis. Such measurements are useful because isotopically fractionating processes may have distinct effects at different molecular sites, and thermodynamically equilibrated populations of molecules tend to concentrate heavy isotopes in one molecular site versus another. Most recent studies of site-specific 13C in organics use specialized Nuclear Magnetic Resonance (NMR) techniques or complex chemical degradations prior to mass spectrometric measurements. Herein we present the first application of a new mass spectrometric technique that reconstructs the site-specific carbon isotope composition of propane based on measurements of the 13C/12C ratios of two or more fragment ions that sample different proportions of the terminal and central carbon sites. We apply this method to propane from laboratory experiments and natural gas samples to explore the relationships between site-specific carbon isotope composition, full-molecular δ13C, thermal maturity, and variation in organic matter precursors. Our goal is to advance the understanding of the sources and histories of short-chain alkanes within geologic systems. Our findings suggest that propane varies in its site-specific carbon isotope structure, which is correlated with increasing thermal maturity, first increasing in terminal position δ13C and then increasing in both center and terminal position δ13C. This pattern is observed in both experimental and natural samples, and is plausibly explained by a combination of site-specific, temperature-dependent isotope effects associated with conversion of different precursor molecules (kerogen, bitumen, and/or oil) to propane, differences in site-specific isotopic contents of those precursors, and possibly distillation of reactive components of those precursors with increasing maturity. We hypothesize that the largest changes in

  13. 26 CFR 1.381(c)(13)-1 - Involuntary conversions.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 4 2010-04-01 2010-04-01 false Involuntary conversions. 1.381(c)(13)-1 Section 1.381(c)(13)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Insolvency Reorganizations § 1.381(c)(13)-1 Involuntary conversions...

  14. Histidine side-chain dynamics and protonation monitored by C-13 CPMG NMR relaxation dispersion

    DEFF Research Database (Denmark)

    Hass, M. A. S.; Yilmaz, A.; Christensen, Hans Erik Mølager

    2009-01-01

    the chemical shift titration experiments, and the CPMG derived exchange rates agree with those obtained previously from N-15 backbone relaxation measurements. Compared to measurements of backbone nuclei, C-13(epsilon 1) dispersion provides a more direct method to monitor interchanging protonation states...... or other kinds of conformational changes of histidine side chains or their environment. Advantages and shortcomings of using the C-13(epsilon 1) dispersion experiments in combination with chemical shift titration experiments to obtain information on exchange dynamics of the histidine side chains...

  15. Inhibitors of the alpha-ketoglutarate dehydrogenase complex alter [1-13C]glucose and [U-13C]glutamate metabolism in cerebellar granule neurons.

    Science.gov (United States)

    Santos, Sónia Sá; Gibson, Gary E; Cooper, Arthur J L; Denton, Travis T; Thompson, Charles M; Bunik, Victoria I; Alves, Paula M; Sonnewald, Ursula

    2006-02-15

    Diminished activity of the alpha-ketoglutarate dehydrogenase complex (KGDHC), an important component of the tricarboxylic acid (TCA) cycle, occurs in several neurological diseases. The effect of specific KGDHC inhibitors [phosphonoethyl ester of succinyl phosphonate (PESP) and the carboxy ethyl ester of succinyl phosphonate (CESP)] on [1-13C]glucose and [U-13C]glutamate metabolism in intact cerebellar granule neurons was investigated. Both inhibitors decreased formation of [4-13C]glutamate from [1-13C]glucose, a reduction in label in glutamate derived from [1-13C]glucose/[U-13C]glutamate through a second turn of the TCA cycle and a decline in the amounts of gamma-aminobutyric acid (GABA), aspartate, and alanine. PESP decreased formation of [U-13C]aspartate and total glutathione, whereas CESP decreased concentrations of valine and leucine. The findings are consistent with decreased KGDHC activity; increased alpha-ketoglutarate formation; increased transamination of alpha-ketoglutarate with valine, leucine, and GABA; and new equilibrium position of the aspartate aminotransferase reaction. Overall, the findings also suggest that some carbon derived from alpha-ketoglutarate may bypass the block in the TCA cycle at KGDHC by means of the GABA shunt and/or conversion of valine to succinate. The results suggest the potential of succinyl phosphonate esters for modeling the biochemical and pathophysiological consequences of reduced KGDHC activity in brain diseases.

  16. 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.

  17. The Nordea Bank Denmark Case (C-48/13

    Directory of Open Access Journals (Sweden)

    Laursen Anders Nørgaard

    2014-11-01

    Full Text Available This paper reports on an investigation of a recent decision by the European Court of Justice (ECJ in case C-48/13, Nordea Bank Denmark, concerning the Danish rules for reincorporation of losses from permanent establishments situated in European Union/ European Economic Area (EU/EEA member states other than Denmark. The article includes comments on various EU tax law aspects of the case - namely the restriction test applied by the ECJ, the justifications brought forward by the intervening governments and the question of proportionality - and examines the consequences of the Danish tax law going forward.

  18. Solid-state nuclear-spin quantum computer based on magnetic resonance force microscopy

    International Nuclear Information System (INIS)

    Berman, G. P.; Doolen, G. D.; Hammel, P. C.; Tsifrinovich, V. I.

    2000-01-01

    We propose a nuclear-spin quantum computer based on magnetic resonance force microscopy (MRFM). It is shown that an MRFM single-electron spin measurement provides three essential requirements for quantum computation in solids: (a) preparation of the ground state, (b) one- and two-qubit quantum logic gates, and (c) a measurement of the final state. The proposed quantum computer can operate at temperatures up to 1 K. (c) 2000 The American Physical Society

  19. The Hoyle state in 12C

    Science.gov (United States)

    Freer, M.; Fynbo, H. O. U.

    2014-09-01

    The 7.65 MeV, Jπ =0+, second excited state in 12C is known as the Hoyle-state after Fred Hoyle. In the 1950s Hoyle proposed the existence of the state in order to account for the stellar abundance of carbon. Aside from its key role in the synthesis of the elements it is believed to possess a rather unusual structure, where the dominant degrees of freedom are those of α-particle clusters rather than nucleons. An understanding of the properties of the Hoyle state, for example its radius and excitations, has been the focus of a major experimental activity. Similarly, unravelling precisely why a cluster state should arise at precisely the right energy to promote synthesis of carbon has been a central theoretical challenge. To a significant extent, the Hoyle-state has become a cornerstone for state-of-the-art nuclear theory. This review examines the present status of both theory and experiment and indicates directions for future developments to resolve some of the remaining open questions.

  20. Advantages of being a nuclear state

    International Nuclear Information System (INIS)

    Ahmadova, S.

    2012-01-01

    Full text : Despite of some progress in the field of nuclear non-proliferation regime at the end of the last century, de-facto nuclear countries, and the issues such as Iran's uranium enrichment activities, the nuclear program of the North Korea proves the regime is in deep crisis. Besides, as a result of rapid scientific and technological development the number of enterprises processing raw material is increasing, the import of materials containing uranium and plutonium is becoming easier and reserves and facilities are widely spread in the black market. Unimpeded access to the information and scientific literature on production of nuclear weapons becomes available, organization and purposeful participation in the events related to the nuclear technology increase, the fact of involvement of scholars and engineers from the developed countries is observed. The growth of nuclear reactors amount with the purpose of energy supply increase the demand for enriched uranium and plutonium, and this hampers the protection these substances. Furthermore, the existence of local natural reserves, the state attention to the staff training able to create nuclear weapons, the staff aware of the work with radioactive substances, the programs considering military preparation on the application of nuclear weapons and so on problems directly threaten the non-proliferation regime. Despite the concern on non-proliferation of nuclear weapons expressed by many scholars and officials, the interest and attempts of states in becoming nuclear states always increase. These interests are stipulated by objective and subjective reasons

  1. 10 CFR 420.13 - Annual State applications and amendments to State plans.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Annual State applications and amendments to State plans. 420.13 Section 420.13 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION STATE ENERGY PROGRAM Formula..., renewable energy, and alternative transportation fuel goals to be achieved, including wherever practicable...

  2. [2,4-(13)C]β-hydroxybutyrate metabolism in astrocytes and C6 glioblastoma cells.

    Science.gov (United States)

    Eloqayli, Haytham; Melø, Torun M; Haukvik, Anne; Sonnewald, Ursula

    2011-08-01

    This study was undertaken to determine if the ketogenic diet could be useful for glioblastoma patients. The hypothesis tested was whether glioblastoma cells can metabolize ketone bodies. Cerebellar astrocytes and C6 glioblastoma cells were incubated in glutamine and serum free medium containing [2,4-(13)C]β-hydroxybutyrate (BHB) with and without glucose. Furthermore, C6 cells were incubated with [1-(13)C]glucose in the presence and absence of BHB. Cell extracts were analyzed by mass spectrometry and media by (1)H magnetic resonance spectroscopy and HPLC. Using [2,4-(13)C]BHB and [1-(13)C]glucose it could be shown that C6 cells, in analogy to astrocytes, had efficient mitochondrial activity, evidenced by (13)C labeling of glutamate, glutamine and aspartate. However, in the presence of glucose, astrocytes were able to produce and release glutamine, whereas this was not accomplished by the C6 cells, suggesting lack of anaplerosis in the latter. We hypothesize that glioblastoma cells kill neurons by not supplying the necessary glutamine, and by releasing glutamate.

  3. CACA-TOCSY with alternate 13C-12C labeling: a 13Cα direct detection experiment for mainchain resonance assignment, dihedral angle information, and amino acid type identification

    International Nuclear Information System (INIS)

    Takeuchi, Koh; Frueh, Dominique P.; Sun, Zhen-Yu J.; Hiller, Sebastian; Wagner, Gerhard

    2010-01-01

    We present a 13 C direct detection CACA-TOCSY experiment for samples with alternate 13 C- 12 C labeling. It provides inter-residue correlations between 13 C α resonances of residue i and adjacent C α s at positions i - 1 and i + 1. Furthermore, longer mixing times yield correlations to C α nuclei separated by more than one residue. The experiment also provides C α -to-sidechain correlations, some amino acid type identifications and estimates for ψ dihedral angles. The power of the experiment derives from the alternate 13 C- 12 C labeling with [1,3- 13 C] glycerol or [2- 13 C] glycerol, which allows utilizing the small scalar 3 J CC couplings that are masked by strong 1 J CC couplings in uniformly 13 C labeled samples.

  4. 13C, 1H spin-spin coupling constants. Pt. 4

    International Nuclear Information System (INIS)

    Aydin, R.; Guenther, H.

    1979-01-01

    One-bond, geminal, and vicinal 13 C, 1 H coupling constants have been determined for adamantane using α-and β-[D]adamantane and the relation sup(n)J( 13 C, 1 H)=6,5144sup(n)J( 13 C, 2 H) for the conversion of the measured sup(n)J( 13 C, 2 H) values. It is shown that the magnitude of 3 Jsub(trans) is strongly influenced by the substitution pattern. Relative H,D isotope effects for 13 C chemical shifts are given. (orig.) [de

  5. Comparison of IRMS and NMR spectrometry for the determination of intramolecular 13C isotope composition: application to ethanol.

    Science.gov (United States)

    Gilbert, Alexis; Hattori, Ryota; Silvestre, Virginie; Wasano, Nariaki; Akoka, Serge; Hirano, Satoshi; Yamada, Keita; Yoshida, Naohiro; Remaud, Gérald S

    2012-09-15

    Isotopic (13)C NMR is a relatively recent technique which allows the determination of intramolecular (13)C isotope composition at natural abundance. It has been used in various scientific fields such as authentication, counterfeiting or plant metabolism. Although its precision has already been evaluated, the determination of its trueness remains still challenging. To deal with that issue, a comparison with another normalized technique must be achieved. In this work, we compare the intramolecular (13)C isotope distribution of ethanol from different origins obtained using both Isotope Ratio Mass Spectrometry (IRMS) and Nuclear Magnetic Resonance (NMR) spectrometry techniques. The IRMS approach consists of the oxidation of ethanol to acetic acid followed by the degradation of the latter for the analysis of each fragments formed. We show here that the oxidation of ethanol to acetic acid does not bring any significant error on the determination of the site-specific δ(13)C (δ(13)C(i)) of ethanol using the IRMS approach. The difference between the data obtained for 16 samples from different origins using IRMS and NMR approaches is not statistically significant and remains below 0.3‰. These results are encouraging for the future studies using isotopic NMR, especially in combination with the IRMS approach. Copyright © 2012. Published by Elsevier B.V.

  6. The ratio of acetate-to-glucose oxidation in astrocytes from a single 13C NMR spectrum of cerebral cortex.

    Science.gov (United States)

    Marin-Valencia, Isaac; Hooshyar, M Ali; Pichumani, Kumar; Sherry, A Dean; Malloy, Craig R

    2015-01-01

    The (13) C-labeling patterns in glutamate and glutamine from brain tissue are quite different after infusion of a mixture of (13) C-enriched glucose and acetate. Two processes contribute to this observation, oxidation of acetate by astrocytes but not neurons, and preferential incorporation of α-ketoglutarate into glutamate in neurons, and incorporation of α-ketoglutarate into glutamine in astrocytes. The acetate:glucose ratio, introduced previously for analysis of a single (13) C NMR spectrum, provides a useful index of acetate and glucose oxidation in the brain tissue. However, quantitation of relative substrate oxidation at the cell compartment level has not been reported. A simple mathematical method is presented to quantify the ratio of acetate-to-glucose oxidation in astrocytes, based on the standard assumption that neurons do not oxidize acetate. Mice were infused with [1,2-(13) C]acetate and [1,6-(13) C]glucose, and proton decoupled (13) C NMR spectra of cortex extracts were acquired. A fit of those spectra to the model indicated that (13) C-labeled acetate and glucose contributed approximately equally to acetyl-CoA (0.96) in astrocytes. As this method relies on a single (13) C NMR spectrum, it can be readily applied to multiple physiologic and pathologic conditions. Differences in (13) C labeling of brain glutamate and glutamine have been attributed to metabolic compartmentation. The acetate:glucose ratio, introduced for description of a (13) C NMR (nuclear magnetic resonance) spectrum, is an index of glucose and acetate oxidation in brain tissue. A simple mathematical method is presented to quantify the ratio of acetate-to-glucose oxidation in astrocytes from a single NMR spectrum. As kinetic analysis is not required, the method is readily applicable to analysis of tissue extracts. α-KG = alpha-ketoglutarate; CAC = citric acid cycle; GLN = glutamine; GLU = glutamate. © 2014 International Society for Neurochemistry.

  7. Determinations of the {sup 12}C/{sup 13}C Ratio for the Secondary Stars of AE Aquarii, SS Cygni, and RU Pegasi

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Thomas E.; Marra, Rachel E., E-mail: tharriso@nmsu.edu, E-mail: rmarra@nmsu.edu [Department of Astronomy, New Mexico State University, Box 30001, MSC 4500, Las Cruces, NM 88003-8001 (United States)

    2017-07-10

    We present new moderate-resolution near-infrared spectroscopy of three CVs obtained using GNIRS on Gemini-North. These spectra covered three {sup 13}CO bandheads found in the K -band, allowing us to derive the isotopic abundance ratios for carbon. We find small {sup 12}C/{sup 13}C ratios for all three donor stars. In addition, these three objects show carbon deficits, with AE Aqr being the most extreme ([C/Fe] = −1.4). This result confirms the conjecture that the donor stars in some long-period CVs have undergone considerable nuclear evolution prior to becoming semi-contact binaries. In addition to the results for carbon, we find that the abundance of sodium is enhanced in these three objects, and the secondary stars in both RU Peg and SS Cyg suffer magnesium deficits. Explaining such anomalies appears to require higher mass progenitors than commonly assumed for the donor stars of CVs.

  8. Nuclear methods and the nuclear equation of state

    CERN Document Server

    1999-01-01

    The theoretical study of the nuclear equation of state (EOS) is a field of research which deals with most of the fundamental problems of nuclear physics. This book gives an overview of the present status of the microscopic theory of the nuclear EOS. Its aim is essentially twofold: first, to serve as a textbook for students entering the field, by covering the different subjects as exhaustively and didactically as possible; second, to be a reference book for all researchers active in the theory of nuclear matter, by providing a report on the latest developments. Special emphasis is given to the

  9. 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.

  10. Report of the State Office for Nuclear Safety on state supervision of nuclear safety of nuclear facilities and radiation protection in 1998

    International Nuclear Information System (INIS)

    1999-05-01

    The legislative basis of the authority of the State Office for Nuclear Safety as the Czech national regulatory body is outlined, its organizational scheme is presented, and the responsibilities of the various departments are highlighted. The operation of major Czech nuclear facilities, including the Dukovany NPP which is in operation and the Temelin NPP which is under construction, is described with respect to nuclear safety. Since the Office's responsibilities also cover radiation protection in the Czech Republic, a survey of ionizing radiation sources and their supervision is given. Other topics include, among other things, nuclear material transport, the state system for nuclear materials accountancy and control, central registries for radiation protection, nuclear waste management, the National Radiation Monitoring Network, personnel qualification and training, emergency planning, legislative activities, international cooperation, and public information. (P.A.)

  11. Synthetic Swan band profile of (1,0) of 12C12C and (0,0) of 12C12C and 12C13C in comets

    International Nuclear Information System (INIS)

    Swamy, K.S.K.

    1987-01-01

    The statistical equilibrium calculations of the 12 C 13 C molecule based on the resonance fluorescence process give similar results to those of the normal molecule. Therefore the assumption that the observed intensities of bands of the normal and the isotopic molecule differ only by their abundance ratio is reasonable. The synthetic profile of the (1,0) Swan band of 12 C 13 C (0,0) band of 12 C 12 C and 12 C 13 C have been calculated. The relative merits of using the rotational structure of the (1,0) or (0,0) band for the determination of the isotopic ratio 12 C/ 13 C is discussed briefly. (author)

  12. The World Nuclear University: New partnership in nuclear education

    International Nuclear Information System (INIS)

    2007-07-01

    The important role which the IAEA plays in assisting Member States in the preservation and enhancement of nuclear knowledge and in facilitating international collaboration in this area has been recognized by the General Conference of the International Atomic Energy Agency in resolutions GC(46)/RES/11B, GC(47)/RES/10B, GC(48)/RES/13 and GC(50)/RES/13. A continued focus of IAEA activities in managing nuclear knowledge is to support Member States to secure and sustain human resources for the nuclear sector, comprising both the replacement of retiring staff and building of new capacity. The IAEA assists Member States, particularly developing ones, in their efforts to sustain nuclear education and training in all areas of nuclear technology for peaceful purposes, which is a necessary prerequisite for succession planning, in particular through the networking of nuclear education and training, including activities of the World Nuclear University (WNU) and the Asian Network for Education in Nuclear Technology (ANENT). The report on the attached CD-ROM, The World Nuclear University: New Partnership in Nuclear Education, gives an overview of the history of the development of the World Nuclear University and related IAEA activities and contains an analysis and recommendations from the first WNU Summer Institute, held in 2005 in the USA

  13. Analyzing power measurements for the /sup 13/C(p vector,d)/sup 12/C reaction at 200 and 400 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Liljestrand, R P; Cameron, J M; Hutcheon, D A; MacDonald, R; McDonald, W J; Miller, C A; Olsen, W C [Alberta Univ., Edmonton (Canada); Kraushaar, J J; Shepard, J R [Colorado Univ., Boulder (USA). Nuclear Physics Lab.; Rogers, J G [British Columbia Univ., Vancouver (Canada). TRIUMF Facility

    1981-02-26

    Cross sections and analyzing powers for the /sup 13/C(p vector,d) reaction have been measured at 200 and 400 MeV to the O/sup +/, ground state and 2/sup +/, 4.44 MeV state of /sup 12/C. While the cross sections are rather structureless, DWBA calculations in exact finite range account well for both the magnitude and shape of the angular distributions. On the other hand, the measured analyzing powers are in serious disagreement with the DWBA calculations.

  14. CACA-TOCSY with alternate 13C-12C labeling: a 13Calpha direct detection experiment for mainchain resonance assignment, dihedral angle information, and amino acid type identification.

    Science.gov (United States)

    Takeuchi, Koh; Frueh, Dominique P; Sun, Zhen-Yu J; Hiller, Sebastian; Wagner, Gerhard

    2010-05-01

    We present a (13)C direct detection CACA-TOCSY experiment for samples with alternate (13)C-(12)C labeling. It provides inter-residue correlations between (13)C(alpha) resonances of residue i and adjacent C(alpha)s at positions i - 1 and i + 1. Furthermore, longer mixing times yield correlations to C(alpha) nuclei separated by more than one residue. The experiment also provides C(alpha)-to-sidechain correlations, some amino acid type identifications and estimates for psi dihedral angles. The power of the experiment derives from the alternate (13)C-(12)C labeling with [1,3-(13)C] glycerol or [2-(13)C] glycerol, which allows utilizing the small scalar (3)J(CC) couplings that are masked by strong (1)J(CC) couplings in uniformly (13)C labeled samples.

  15. Estimation of glucose carbon recycling in children with glycogen storage disease: A 13C NMR study using [U-13C]glucose

    International Nuclear Information System (INIS)

    Kalderon, B.; Korman, S.H.; Gutman, A.; Lapidot, A.

    1989-01-01

    A stable isotope procedure to estimate hepatic glucose carbon recycling and thereby elucidate the mechanism by which glucose is produced in patients lacking glucose 6-phosphatase is described. A total of 10 studies was performed in children with glycogen storage disease type I (GSD-I) and type III (GSD-III) and control subjects. A primed dose-constant nasogastric infusion of D-[U- 13 C]glucose or an infusion diluted with nonlabeled glucose solution was administered following different periods of fasting. Hepatic glucose carbon recycling was estimated from 13 C NMR spectra. The values obtained for GSD-I patients coincided with the standard [U- 13 C]glucose dilution curve. These results indicate that the plasma glucose of GSD-I subjects comprises only a mixture of 99% 13 C-enriched D-[U- 13 C]glucose and unlabeled glucose but lacks any recycled glucose. Significantly different glucose carbon recycling values were obtained for two GSD-III patients in comparison to GSD-I patients. The results eliminate a mechanism for glucose production in GSD-I children involving gluconeogenesis. However, glucose release by amylo-1,6-glucosidase activity would result in endogenous glucose production of non- 13 C-labeled and nonrecycled glucose carbon, as was found in this study. In GSD-III patients gluconeogenesis is suggested as the major route for endogenous glucose synthesis. The contribution of the triose-phosphate pathway in these patients has been determined

  16. Strategy of nuclear power in Korea, non-nuclear-weapon state and peaceful use of nuclear power

    International Nuclear Information System (INIS)

    Nagasaki, Takao

    2005-01-01

    The nuclear power plant started at Kori in Korea in April, 1978. Korea has carried out development of nuclear power as a national policy. The present capacity of nuclear power plants takes the sixes place in the world. It supplies 42% total power generation. The present state of nuclear power plant, nuclear fuel cycle facility, strategy of domestic production of nuclear power generation, development of next generation reactor and SMART, strategy of export in corporation with industry, government and research organization, export of nuclear power generation in Japan, nuclear power improvement project with Japan, Korea and Asia, development of nuclear power system with nuclear diffusion resistance, Hybrid Power Extraction Reactor System, radioactive waste management and construction of joint management and treatment system of spent fuel in Asia are stated. (S.Y.)

  17. Determination of the 13C/12C ratio of ethanol derived from fruit juices and maple syrup by isotope ratio mass spectrometry: collaborative study.

    Science.gov (United States)

    Jamin, Eric; Martin, Frédérique; Martin, Gilles G

    2004-01-01

    A collaborative study of the carbon-13 isotope ratio mass spectrometry (13C-IRMS) method based on fermentation ethanol for detecting some sugar additions in fruit juices and maple syrup is reported. This method is complementary to the site-specific natural isotope fractionation by nuclear magnetic resonance (SNIF-NMR) method for detecting added beet sugar in the same products (AOAC Official Methods 995.17 and 2000.19), and uses the same initial steps to recover pure ethanol. The fruit juices or maple syrups are completely fermented with yeast, and the alcohol is distilled with a quantitative yield (>96%). The carbon-13 deviation (delta13C) of ethanol is then determined by IRMS. This parameter becomes less negative when exogenous sugar derived from plants exhibiting a C4 metabolism (e.g., corn or cane) is added to a juice obtained from plants exhibiting a C3 metabolism (most common fruits except pineapple) or to maple syrup. Conversely, the delta13C of ethanol becomes more negative when exogenous sugar derived from C3 plants (e.g., beet, wheat, rice) is added to pineapple products. Twelve laboratories analyzed 2 materials (orange juice and pure cane sugar) in blind duplicate and 4 sugar-adulterated materials (orange juice, maple syrup, pineapple juice, and apple juice) as Youden pairs. The precision of that method for measuring delta13C was similar to that of other methods applied to wine ethanol or extracted sugars in juices. The within-laboratory (Sr) values ranged from 0.06 to 0.16%o (r = 0.17 to 0.46 percent per thousand), and the among-laboratories (SR) values ranged from 0.17 to 0.26 percent per thousand (R = 0.49 to 0.73 percent per thousand). The Study Directors recommend that the method be adopted as First Action by AOAC INTERNATIONAL.

  18. Isospin dependence of nuclear charge radii and its microscopic demonstration

    International Nuclear Information System (INIS)

    Lei Yian; Zeng Jinyan

    2007-01-01

    The analysis of experimental nuclear charge radii R c indicates that R c deviates systematically from the A 1/3 law, i.e., R c /A 1/3 gradually decreases with increasing A, whereas R c /Z 1/3 remains almost a constant. This statement is also supported by the analysis of a large amount of experimental nuclear giant monopole resonance energy data E x ∝R -1 . The deviation of nuclear charge radii from the A 1/3 law is basically caused by the isospin independence of A 1/3 law, and the isospin dependence has been partly included in Z 1/3 law. In the frame of nuclear shell model, a microscopic demonstration of the Z 1/3 law is given. The difference in the harmonic oscillator potential strength between proton and neutron (ω p and ω n ) can be accounted for by the Z 1/3 law. Similar to Wigner's nuclear isobaric multiplet mass equation (IMME), a modified Z 1/3 law for nuclear charge radii is proposed. (authors)

  19. Effect of alcohol consumption on the liver detoxication capacity as measured by [13C2]aminopyrine and L-[1-13C]phenylalanine breath tests.

    Science.gov (United States)

    Wutzke, Klaus D; Wigger, Marianne

    2009-09-01

    The aim of this study was to investigate the hepatic microsomal and cytosolic functions by using the 13CO2 breath test in healthy subjects either before or after consumption of red wine. Twelve adults received [13C2]aminopyrine and L-[1-13C]phenylalanine together with a standardised dinner. Expired air samples were taken over 6 h. After a wash-out period, the subjects consumed 0.4 ml ethanol per kg per day together with dinner over a 7.5-day period on average. Thereafter, 13C-tracer administration was repeated under identical conditions. The 13CO2 enrichments were measured by isotope ratio mass spectrometry. The mean cumulative percentage 13C-dose recovery after administration of [13C2]aminopyrine and L-[1-13C]phenylalanine either without or with red wine consumption amounted to 17.0+/-4.4 vs. 14.7+/-3.1% (p=0.170) and 14.0+/-2.8 vs. 11.5+/-3.9% (p=0.084), respectively. Moderate alcohol consumption does not induce significant short-term changes of the microsomal and the cytosolic function of the human liver in healthy subjects.

  20. Delta /sup 13/C fractionation in Tarbela dam fish

    International Nuclear Information System (INIS)

    Latif, Z.; Sajjad, M.I.; Bilal, R.; Tasneem, M.A.; Khan, I.H.; Ali, M.

    1998-01-01

    The paper focuses on the study of naturally occurring /sup 13/C fractionation in Tarbela dam fish. Craig noted that gamma /sup 13/C values for animal tissues fall in the range as their food supply. DeNiro and Epstein demonstrated clearly that the carbon isotope composition of an animal greatly depends on its diet. The above mentioned statements were observed while studying the isotopic composition of carbon in different parts of the fish. Living fish was purchased from the Haripur side of the Tarbela lake. Different portions were separated and fish diet was collected from the fish stomach. Samples were dried in the oven at 40-50 deg. C for five days. Ground, homogenized and ignited with research grade oxygen at 900-1000 deg. C. CO and CO /sub 2/ were produced and CO was converted to CO/sub 2/ by circulation over CuO gauge furnace at 900 deg. C. CO/sub 2/ was purified using 70 deg. C slush and analyzed on Varian Mat (GD-150) mass spectrometer for gamma /sup 13/C measurements. The results show that fish flesh sup/13 C value is nearly similar to fish diet gamma /sup 13/C. gamma /sup 13/C values to different parts of the fish departed from that of the diet in the sequence: fish swim bladder (-22.04) >ribs (2-22.26)>skin (122.91)>diet (123.22)>flesh (-23.40)> vertebral column (-24.07). It is concluded that diet is easily metabolized in the fish flesh and skin tissues through blood streams without causing any pronounced fractionation. Fractionation was observed in the fish endo skeleton system due to which fish ribs become enriched in gamma /sup 13/C than vertebral column. Fractionation was also detected in visceral muscles (swim bladder) of the fish as comparison with somatic axial trunk muscle (fish flesh). (author)

  1. Dynamic nuclear polarization of nucleic acid with endogenously bound manganese

    International Nuclear Information System (INIS)

    Wenk, Patricia; Kaushik, Monu; Richter, Diane; Vogel, Marc; Suess, Beatrix; Corzilius, Björn

    2015-01-01

    We report the direct dynamic nuclear polarization (DNP) of 13 C nuclei of a uniformly [ 13 C, 15 N]-labeled, paramagnetic full-length hammerhead ribozyme (HHRz) complex with Mn 2+ where the enhanced polarization is fully provided by the endogenously bound metal ion and no exogenous polarizing agent is added. A 13 C enhancement factor of ε = 8 was observed by intra-complex DNP at 9.4 T. In contrast, “conventional” indirect and direct DNP experiments were performed using AMUPol as polarizing agent where we obtained a 1 H enhancement factor of ε ≈ 250. Comparison with the diamagnetic (Mg 2+ ) HHRz complex shows that the presence of Mn 2+ only marginally influences the (DNP-enhanced) NMR properties of the RNA. Furthermore two-dimensional correlation spectra ( 15 N– 13 C and 13 C– 13 C) reveal structural inhomogeneity in the frozen, amorphous state indicating the coexistence of several conformational states. These demonstrations of intra-complex DNP using an endogenous metal ion as well as DNP-enhanced MAS NMR of RNA in general yield important information for the development of new methods in structural biology

  2. Effects of pyruvate dose on in vivo metabolism and quantification of hyperpolarized 13C spectra

    DEFF Research Database (Denmark)

    Janich, M. A.; Menzel, M. I.; Wiesinger, F.

    2012-01-01

    Real‐time in vivo measurements of metabolites are performed by signal enhancement of [1‐13C]pyruvate using dynamic nuclear polarization, rapid dissolution and intravenous injection, acquisition of free induction decay signals and subsequent quantification of spectra. The commonly injected dose...... uptake and metabolic conversion. The goal of this study was to examine the effects of a [1‐13C]pyruvate bolus on metabolic conversion in vivo. Spectra were quantified by three different methods: frequency‐domain fitting with LCModel, time‐domain fitting with AMARES and simple linear least‐squares fitting...... in the time domain. Since the simple linear least‐squares approach showed bleeding artifacts and LCModel produced noisier time signals. AMARES performed best in the quantification of in vivo hyperpolarized pyruvate spectra. We examined pyruvate doses of 0.1–0.4 mmol/kg (body mass) in male Wistar rats...

  3. The Microwave Spectroscopy of HCOO^{13}CH_3 in the Second Torsional Excited State

    Science.gov (United States)

    Kobayashi, Kaori; Kuwahara, Takuro; Urata, Yuki; Ohashi, Nobukimi; Fujitake, Masaharu

    2017-06-01

    Methyl formate (HCOOCH_3) is an abundant interstellar molecule, found almost everywhere in the star-forming region. The interstellar abundance of the ^{13}C is about 1/50 of ^{12}C. The ^{13}C substituted methyl formate in the ground and first excited states were already found toward massive star-forming regions including Orion KL. With the aid of the state-of-the-art telescope like ALMA, the pure rotational transitions in the second torsional excited may be identified in the near future and laboratory data are necessary. We recorded the spectra of HCOOCH_3 below 340 GHz by using conventional source-modulation microwave spectrometer. The assignment of the pure rotational spectra in the second torsional excited state and the analysis by using pseudo-PAM Hamiltonian, which was effective to analyze the normal species, will be reported. C. Favre, M. Carvajal, D. Field, J. K. Jørgensen, S. E. Bisschop, N. Brouillet, D. Despois, A. Baudry, I. Kleiner, E. A. Bergin, N. R. Crockett, J. L. Neill, L. Marguès, T. R. Huet, and J. Demaison, Astrophys. J. Suppl. Ser. 215, 25 (2014).

  4. Probing cardiac metabolism by hyperpolarized 13C MR using an exclusively endogenous substrate mixture and photo-induced nonpersistent radicals

    DEFF Research Database (Denmark)

    Bastiaansen, Jessica A M; Yoshihara, Hikari A I; Capozzi, Andrea

    2018-01-01

    dissolved, and the radical-free hyperpolarized solution was rapidly transferred into an injection pump located inside a 9.4T scanner. The hyperpolarized solution was injected in healthy rats to measure cardiac metabolism in vivo. Ultraviolet irradiation created nonpersistent radicals in a mixture containing......To probe the cardiac metabolism of carbohydrates and short chain fatty acids simultaneously in vivo following the injection of a hyperpolarized 13 C-labeled substrate mixture prepared using photo-induced nonpersistent radicals. Droplets of mixed [1-13 C]pyruvic and [1-13 C]butyric acids were frozen...... into glassy beads in liquid nitrogen. Ethanol addition was investigated as a means to increase the polarization level. The beads were irradiated with ultraviolet light and the radical concentration was measured by ESR spectroscopy. Following dynamic nuclear polarization in a 7T polarizer, the beads were...

  5. First Spectroscopic Studies and Detection in SgrB2 of 13C-DOUBLY Substitued Ethyl Cyanide

    Science.gov (United States)

    Margulès, L.; Motiyenko, R. A.; Guillemin, J.-C.; Müller, Holger S. P.; Belloche, Arnaud

    2015-06-01

    Ethyl cyanide (CH_3CH_2CN) is one of the most abundant complex organic molecules in the interstellar medium firstly detected in OMC-1 and Sgr B2 in 1977. The vibrationally excited states are enough populated under ISM conditions and could be detected. Apart from the deuterated ones, all mono-substituted isotopologues of ethyl cyanide (13C and 15N have been detected in the ISM. The detection of isotopologues in the ISM is important: it can give information about the formation process of complex organic molecules, and it is essential to clean the ISM spectra from the lines of known molecules in order to detect new ones. The 12C/13C ratio found in SgrB2: 20-30 suggests that the doubly 13C could be present in the spectral line survey recently obtained with ALMA (EMoCA), but no spectroscopic studies exist up to now. We measured and analyzed the spectra of the 13C-doubly-substitued species up to 1 THz with the Lille solid-state based spectrometer. The spectroscopic results and and the detection of the doubly 13C species in SgrB2 will be presented. This work was supported by the CNES and the Action sur Projets de l'INSU, PCMI. This work was also done under ANR-13-BS05-0008-02 IMOLABS. Support by the Deutsche Forschungsgemeinschaft via SFB 956, project B3 is acknowledged D.~R.~Johnson, et al., Astrophys.~J. 1977, 218, L370 A.~Belloche, et al., A&A 2013, 559, A47 A.M.~Daly, et al., Astrophys.~J. 2013, 768, 81 K.~Demyk, et al. A&A 2007 466, 255 Margulès, et al. A&A 2009, 493, 565 Belloche et al. 2014, Science, 345, 1584

  6. Carbon-13 solid state NMR studies in the aromatization of residual coals from hydropyrolised cellulose; Estudo por {sup 13} C RMN em estado solido da aromatizacao em carvoes residuais de celulose hidropirolisada

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, J.D.; Luengo, C.A. [Universidade Estadual de Campinas, SP (Brazil). Inst. de Fisica; Snape, C.A. [Dept. Pure and Apllied Chemistry, Glasgow (United Kingdom)

    1997-12-31

    Pure cellulose was pyrolyzed is a fixed-bed reactor under hydrogen pressure (hydropyrolysis). Residual chars were collected and analysed by solid state nmr {sup 13} C (CP-MAS) and elemental. Hydrophyrolysis parameters such as final temperature in the range of 300 to 520 deg C and hydrogen pressure from 5 to 100 atm gave different char samples. CP-MAS spectra were obtained in a BRUKER MSL-100 spectrometer. The results showed that the aromatic and aliphatic fractions had strong dependence with temperature and no influence with pressure. Elemental analysis indicated the carbon content increased more with temperature than the pressure increasing. (author) 6 refs., 2 figs., 2 tabs.

  7. 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

  8. Astrophysical reaction rate for the neutron-generator reaction 13C(alpha,n)16O in asymptotic giant branch stars.

    Science.gov (United States)

    Johnson, E D; Rogachev, G V; Mukhamedzhanov, A M; Baby, L T; Brown, S; Cluff, W T; Crisp, A M; Diffenderfer, E; Goldberg, V Z; Green, B W; Hinners, T; Hoffman, C R; Kemper, K W; Momotyuk, O; Peplowski, P; Pipidis, A; Reynolds, R; Roeder, B T

    2006-11-10

    The reaction 13C(alpha,n) is considered to be the main source of neutrons for the s process in asymptotic giant branch stars. At low energies, the cross section is dominated by the 1/2+ 6.356 MeV subthreshold resonance in (17)O whose contribution at stellar temperatures is uncertain by a factor of 10. In this work, we performed the most precise determination of the low-energy astrophysical S factor using the indirect asymptotic normalization (ANC) technique. The alpha-particle ANC for the subthreshold state has been measured using the sub-Coulomb alpha-transfer reaction ((6)Li,d). Using the determined ANC, we calculated S(0), which turns out to be an order of magnitude smaller than in the nuclear astrophysics compilation of reaction rates.

  9. 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.

  10. Late pleistocene-recent atmospheric δ13C record in C4 grasses

    International Nuclear Information System (INIS)

    Toolin, L.J.; Eastoe, C.

    1993-01-01

    Samples of Setaria species from packrat middens, herbarium specimens and modern plants preserve a record of δ 13 C of atmospheric CO 2 from 12,600 Bp to the present. No secular trend is detected between 12,600 and 1,800 Bp, when the mean value of δ 13 C during that period was -6.5 ± 0.1 per-thousand (the error is the standard deviation of the mean). The value agrees with δ 13 C averages of pre-industrial CO 2 from polar ice cores, and differs significantly from modern regional (-8.2 ± 0.1 per-thousand) and global (-7.7 per-thousand) values, which are higher because of fossil fuel burning

  11. 13C and 1H nuclear magnetic resonance of methyl-substituted acetophenones and methyl benzoates: steric hindrance and inhibited conjugation.

    Science.gov (United States)

    Budesínský, Milos; Kulhánek, Jirí; Böhm, Stanislav; Cigler, Petr; Exner, Otto

    2004-10-01

    The 1H and 13C NMR spectra of 14 methyl-substituted acetophenones and 14 methyl-substituted methyl benzoates were assigned and interpreted with respect to the conformation of the C(ar)-C(O) bond. The substituent effects are proportional in the two series and can be divided into polar and steric: each has different effects on the 13C SCS of the individual atoms. In the case of C atoms C(O), C(1) and CH3(CO), the steric effects were quantitatively separated by comparing SCS in the ortho and para positions. The steric effects are proportional for the individual C atoms and also to steric effects estimated from other physical quantities. However, they do not depend simply on the angle of torsion phi of the functional group as anticipated hitherto. A better description distinguishes two classes of compounds: sterically not hindered or slightly hindered planar molecules and strongly sterically hindered, markedly non-planar. In order to confirm this reasoning without empirical correlations, the J(C,C) coupling constants were measured for three acetophenone derivatives labeled with 13C in the acetyl methyl group. The constants confirm unambiguously the conformation of 2-methylacetophenone; their zero values are in accord with the conformation of 2,6-dimethylacetophenone. The zero values in the unsubstituted acetophenone are at variance with previous erroneous report but all J(C,C) values are in accord with calculations at the B3LYP/6-311++G(2d,2p)//B3LYP/6-311+G(d,p) level. Copyright 2004 John Wiley & Sons, Ltd.

  12. Detection of interstellar (C-13)N toward Zeta Ophiuchi

    International Nuclear Information System (INIS)

    Crane, P.; Hegyi, D.J.

    1988-01-01

    Observations of a diffuse interstellar cloud toward Zeta Oph, obtained with resolution 100,000-150,000 near the 3874.608-A R(0) line of (C-12)N using a coude echelle spectrograph on the 1.4-m telescope at ESO during 1984 and 1985, are reported. Data from 54 20-min runs were fitted to Gaussian line shapes using the line center, depth, and width of the R(0) and R(1) lines of (C-12)N and the line center and depth of the R(0) line of (C-13)N as fitting parameters. The (C-13)N R(0) line, with equivalent width 0.190 + or - 0.020 mA, was detected 173.7 + or - 0.8 mA to the red of (C-12)N R(0); the corresponding isotope abundance ratio, (C-12)N/(C-13)N = 47.3 + 5.5 or -4.4, is shown to be in good agreement with previous measurements for CH(+) (Hawkins et al., 1985). 13 references

  13. 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.

  14. {sup 14}C emission from Swedish nuclear power plants and its effect on the {sup 14}C levels in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Stenstroem, K.; Erlandsson, Bengt; Hellborg, R.; Kiisk, M.; Persson, Per [Lund Univ. (Sweden). Dept. of Nuclear Physics; Mattsson, Soeren; Thornberg, C. [Lund Univ., Malmoe (Sweden). Dept. of Radiation Physics; Skog, G. [Lund Univ. (Sweden). Dept. of Quaternary Geology

    2000-02-15

    The radionuclide {sup 14}C is produced in all types of nuclear reactors mainly by neutron induced reactions in oxygen ({sup 17}O), nitrogen ({sup 14}N) and carbon ({sup 13}C). Part of the {sup 14}C created is continuously released during normal operation as airborne effluents in various chemical forms (such as CO{sub 2}, CO and hydrocarbons) to the surroundings. Because of the biological importance of carbon and the long physical half-life of {sup 14}C, it is of interest to measure the releases and their incorporation into living material. The {sup 14}C activity concentrations in annual tree rings and air around two Swedish nuclear power plants (Barsebaeck and Forsmark) as well as the background {sup 14}C activity levels from two reference sites in southern Sweden during 1973-1996 are presented in this report. In order to verify the reliability of the method some investigations have been conducted at two foreign nuclear sites, Sellafield fuel reprocessing plant in England, and Pickering nuclear generating station in Canada, where the releases of {sup 14}C are known to be substantial. Furthermore, results from some measurements in the vicinity of Paldiski submarine training centre in Estonia are presented. The results of the {sup 14}C measurements of air, vegetation and annual tree rings around the two Swedish nuclear power plants show very low enhancements of {sup 14}C, if at all above the uncertainty of the measurements. Even if the accuracy of the measurements of the annual tree rings is rather good (1-2%) the contribution of {sup 14}C from the reactors to the environment is so small that it is difficult to separate it from the prevailing background levels of {sup 14}C . This is the case for all sampling procedures: in air and vegetation as well as in annual tree rings. Only on a few occasions an actual increase is observed. However, although the calculations suffer from rather large uncertainties, the calculated release rate from Barsebaeck is in fair agreement

  15. Objective and Essential Elements of a State's Nuclear Security Regime. Nuclear Security Fundamentals (Chinese Edition)

    International Nuclear Information System (INIS)

    2014-01-01

    The possibility that nuclear material or other radioactive material could be used for criminal purposes or intentionally used in an unauthorized manner cannot be ruled out in the current global situation. States have responded to this risk by engaging in a collective commitment to strengthen the protection and control of such material and to respond effectively to nuclear security events. States have agreed to strengthen existing instruments and have established new international legal instruments to enhance nuclear security worldwide. Nuclear security is fundamental in the management of nuclear technologies and in applications where nuclear material or other radioactive material is used or transported. Through its nuclear security programme, the IAEA supports States to establish, maintain and sustain an effective nuclear security regime. The IAEA has adopted a comprehensive approach to nuclear security. This recognizes that an effective national nuclear security regime builds on: the implementation of relevant international legal instruments; information protection; physical protection; material accounting and control; detection of and response to trafficking in such material; national response plans; and contingency measures. With its Nuclear Security Series, the IAEA aims to assist States in implementing and sustaining such a regime in a coherent and integrated manner. The IAEA Nuclear Security Series comprises: Nuclear Security Fundamentals, which include the objective and essential elements of a State's nuclear security regime; Recommendations; Implementing Guides; and Technical Guidance. Each State carries the full responsibility for nuclear security. Specifically, each State has the responsibility to provide for the security of nuclear material and other radioactive material and their associated facilities and activities; to ensure the security of such material in use, storage, or in transport; to combat illicit trafficking and the inadvertent movement of

  16. Objective and Essential Elements of a State's Nuclear Security Regime. Nuclear Security Fundamentals (Arabic Edition)

    International Nuclear Information System (INIS)

    2014-01-01

    The possibility that nuclear material or other radioactive material could be used for criminal purposes or intentionally used in an unauthorized manner cannot be ruled out in the current global situation. States have responded to this risk by engaging in a collective commitment to strengthen the protection and control of such material and to respond effectively to nuclear security events. States have agreed to strengthen existing instruments and have established new international legal instruments to enhance nuclear security worldwide. Nuclear security is fundamental in the management of nuclear technologies and in applications where nuclear material or other radioactive material is used or transported. Through its nuclear security programme, the IAEA supports States to establish, maintain and sustain an effective nuclear security regime. The IAEA has adopted a comprehensive approach to nuclear security. This recognizes that an effective national nuclear security regime builds on: the implementation of relevant international legal instruments; information protection; physical protection; material accounting and control; detection of and response to trafficking in such material; national response plans; and contingency measures. With its Nuclear Security Series, the IAEA aims to assist States in implementing and sustaining such a regime in a coherent and integrated manner. The IAEA Nuclear Security Series comprises: Nuclear Security Fundamentals, which include the objective and essential elements of a State's nuclear security regime; Recommendations; Implementing Guides; and Technical Guidance. Each State carries the full responsibility for nuclear security. Specifically, each State has the responsibility to provide for the security of nuclear material and other radioactive material and their associated facilities and activities; to ensure the security of such material in use, storage, or in transport; to combat illicit trafficking and the inadvertent movement of

  17. Objective and Essential Elements of a State's Nuclear Security Regime. Nuclear Security Fundamentals (Spanish Edition)

    International Nuclear Information System (INIS)

    2014-01-01

    The possibility that nuclear material or other radioactive material could be used for criminal purposes or intentionally used in an unauthorized manner cannot be ruled out in the current global situation. States have responded to this risk by engaging in a collective commitment to strengthen the protection and control of such material and to respond effectively to nuclear security events. States have agreed to strengthen existing instruments and have established new international legal instruments to enhance nuclear security worldwide. Nuclear security is fundamental in the management of nuclear technologies and in applications where nuclear material or other radioactive material is used or transported. Through its nuclear security programme, the IAEA supports States to establish, maintain and sustain an effective nuclear security regime. The IAEA has adopted a comprehensive approach to nuclear security. This recognizes that an effective national nuclear security regime builds on: the implementation of relevant international legal instruments; information protection; physical protection; material accounting and control; detection of and response to trafficking in such material; national response plans; and contingency measures. With its Nuclear Security Series, the IAEA aims to assist States in implementing and sustaining such a regime in a coherent and integrated manner. The IAEA Nuclear Security Series comprises: Nuclear Security Fundamentals, which include the objeurity Fundamentals, which include the objective and essential elements of a State's nuclear security regime; Recommendations; Implementing Guides; and Technical Guidance. Each State carries the full responsibility for nuclear security. Specifically, each State has the responsibility to provide for the security of nuclear material and other radioactive material and their associated facilities and activities; to ensure the security of such material in use, storage, or in transport; to combat illicit

  18. Objective and Essential Elements of a State's Nuclear Security Regime. Nuclear Security Fundamentals (French Edition)

    International Nuclear Information System (INIS)

    2014-01-01

    The possibility that nuclear material or other radioactive material could be used for criminal purposes or intentionally used in an unauthorized manner cannot be ruled out in the current global situation. States have responded to this risk by engaging in a collective commitment to strengthen the protection and control of such material and to respond effectively to nuclear security events. States have agreed to strengthen existing instruments and have established new international legal instruments to enhance nuclear security worldwide. Nuclear security is fundamental in the management of nuclear technologies and in applications where nuclear material or other radioactive material is used or transported. Through its nuclear security programme, the IAEA supports States to establish, maintain and sustain an effective nuclear security regime. The IAEA has adopted a comprehensive approach to nuclear security. This recognizes that an effective national nuclear security regime builds on: the implementation of relevant international legal instruments; information protection; physical protection; material accounting and control; detection of and response to trafficking in such material; national response plans; and contingency measures. With its Nuclear Security Series, the IAEA aims to assist States in implementing and sustaining such a regime in a coherent and integrated manner. The IAEA Nuclear Security Series comprises: Nuclear Security Fundamentals, which include the objective and essential elements of a State's nuclear security regime; Recommendations; Implementing Guides; and Technical Guidance. Each State carries the full responsibility for nuclear security. Specifically, each State has the responsibility to provide for the security of nuclear material and other radioactive material and their associated facilities and activities; to ensure the security of such material in use, storage, or in transport; to combat illicit trafficking and the inadvertent movement of

  19. The synthesis of Org 3770 labelled with 3H, 13C and 14C

    International Nuclear Information System (INIS)

    Kaspersen, F.M.; Rooij, F.A.M. van; Sperling, E.G.M.; Wieringa, J.H.

    1989-01-01

    The syntheses of 1,2,3,4,10,14b-hexahydro-2-methylpyrazino[2,1-a]pyrido[2,3-c][2]benazepine (Org 3770) labelled with 3 H (and 2 H), 13 C and 14 C are described. Tritiated Org 3770 was prepared either by exchange under alkaline conditions with tritiated water or catalytic reductive dehalogenation of a chloro analogue with 3 H 2 . 13 C-labelled material was obtained in a seven-step synthesis starting from 13 C-labelled benzene whereas 14 C-Org 3770 was prepared in a three-step synthesis starting with 14 CO 2 . All labelled compounds were analyzed by TLC, HPLC, MS and NMR. (author)

  20. Search for resonant states in 10C and 11C and their impact on the primordial 7Li abundance

    Science.gov (United States)

    Hammache, F.; Coc, A.; de Séréville, N.; Stefan, I.; Roussel, P.; Assié, M.; Audouin, L.; Beaumel, D.; Franchoo, S.; Fernandez-Dominguez, B.; Fox, S.; Hamadache, C.; Kiener, J.; Laird, A.; Le Crom, B.; Lefebvre-Schuhl, A.; Lefebvre, L.; Matea, I.; Matta, A.; Mavilla, G.; Mrazek, J.; Morfouace, P.; de Oliveira Santos, F.; Parikh, A.; Perrot, L.; Sanchez-Benitez, A. M.; Suzuki, D.; Tatischeff, V.; Ujic, P.; Vandebrouck, Marine

    2018-01-01

    The cosmological 7Li problem arises from the significant discrepancy of about a factor 3 between the predicted primordial 7Li abundance and the observed one. The main process for the production of 7Li during Big-Bang nucleosynthesis is the decay of 7Be. Many key nuclear reactions involved in the production and destruction of 7Be were investigated in attempt to explain the 7Li deficit but none of them led to successful conclusions. However, some authors suggested recently the possibility that the destruction of 7Be by 3He and 4He may reconcile the predictions and observations if missing resonant states in the compound nuclei 10C and 11C exist. Hence, a search of these missing resonant states in 10C and 11C was investigated at the Orsay Tandem-Alto facility through 10B(3He,t)10C and 11B(3He,t)11C charge-exchange reactions respectively. After a short overview of the cosmological 7Li problem from a nuclear physics point of view, a description of the Orsay experiment will be given as well as the obtained results and their impact on the 7Li problem.

  1. Theory of long-lived nuclear spin states in methyl groups and quantum-rotor induced polarisation.

    Science.gov (United States)

    Dumez, Jean-Nicolas; Håkansson, Pär; Mamone, Salvatore; Meier, Benno; Stevanato, Gabriele; Hill-Cousins, Joseph T; Roy, Soumya Singha; Brown, Richard C D; Pileio, Giuseppe; Levitt, Malcolm H

    2015-01-28

    Long-lived nuclear spin states have a relaxation time much longer than the longitudinal relaxation time T1. Long-lived states extend significantly the time scales that may be probed with magnetic resonance, with possible applications to transport and binding studies, and to hyperpolarised imaging. Rapidly rotating methyl groups in solution may support a long-lived state, consisting of a population imbalance between states of different spin exchange symmetries. Here, we expand the formalism for describing the behaviour of long-lived nuclear spin states in methyl groups, with special attention to the hyperpolarisation effects observed in (13)CH3 groups upon rapidly converting a material with low-barrier methyl rotation from the cryogenic solid state to a room-temperature solution [M. Icker and S. Berger, J. Magn. Reson. 219, 1 (2012)]. We analyse the relaxation properties of methyl long-lived states using semi-classical relaxation theory. Numerical simulations are supplemented with a spherical-tensor analysis, which captures the essential properties of methyl long-lived states.

  2. Theory of long-lived nuclear spin states in methyl groups and quantum-rotor induced polarisation

    International Nuclear Information System (INIS)

    Dumez, Jean-Nicolas; Håkansson, Pär; Mamone, Salvatore; Meier, Benno; Stevanato, Gabriele; Hill-Cousins, Joseph T.; Roy, Soumya Singha; Brown, Richard C. D.; Pileio, Giuseppe; Levitt, Malcolm H.

    2015-01-01

    Long-lived nuclear spin states have a relaxation time much longer than the longitudinal relaxation time T 1 . Long-lived states extend significantly the time scales that may be probed with magnetic resonance, with possible applications to transport and binding studies, and to hyperpolarised imaging. Rapidly rotating methyl groups in solution may support a long-lived state, consisting of a population imbalance between states of different spin exchange symmetries. Here, we expand the formalism for describing the behaviour of long-lived nuclear spin states in methyl groups, with special attention to the hyperpolarisation effects observed in 13 CH 3 groups upon rapidly converting a material with low-barrier methyl rotation from the cryogenic solid state to a room-temperature solution [M. Icker and S. Berger, J. Magn. Reson. 219, 1 (2012)]. We analyse the relaxation properties of methyl long-lived states using semi-classical relaxation theory. Numerical simulations are supplemented with a spherical-tensor analysis, which captures the essential properties of methyl long-lived states

  3. Distinct solvent- and temperature-dependent packing arrangements of anti-parallel β-sheet polyalanines studied with solid-state 13C NMR and MD simulation.

    Science.gov (United States)

    Kametani, Shunsuke; Tasei, Yugo; Nishimura, Akio; Asakura, Tetsuo

    2017-08-09

    Polyalanine (polyA) sequences are well known as the simplest sequence that naturally forms anti-parallel β-sheets and constitute a key element in the structure of spider and wild silkworm silk fibers. We have carried out a systematic analysis of the packing of anti-parallel β-sheets for (Ala) n , n = 5, 6, 7 and 12, using primarily 13 C solid-state NMR and MD simulation. HFIP and TFA are frequently used as the dope solvents for recombinant silks, and polyA was solidified from both HFIP and TFA solutions by drying. An analysis of Ala Cβ peaks in the 13 C CP/MAS NMR spectra indicated that polyA from HFIP was mainly rectangular but polyA from TFA was mainly staggered. The transition from the rectangular to the staggered arrangement in (Ala) 6 was observed for the first time from the change in the Ala Cβ peak through heat treatment at 200 °C for 4 h. The removal of the bound water was confirmed by thermal analysis. This transition could be reproduced by MD simulation of (Ala) 6 molecules at 200 °C after removal of the bound water molecules. In this way, the origin of the stability of the different packing arrangements of polyA was clarified.

  4. Site-selective {sup 13}C labeling of proteins using erythrose

    Energy Technology Data Exchange (ETDEWEB)

    Weininger, Ulrich, E-mail: ulrich.weininger@physik.uni-halle.de [Lund University, Department of Biophysical Chemistry, Center for Molecular Protein Science (Sweden)

    2017-03-15

    NMR-spectroscopy enables unique experimental studies on protein dynamics at atomic resolution. In order to obtain a full atom view on protein dynamics, and to study specific local processes like ring-flips, proton-transfer, or tautomerization, one has to perform studies on amino-acid side chains. A key requirement for these studies is site-selective labeling with {sup 13}C and/or {sup 1}H, which is achieved in the most general way by using site-selectively {sup 13}C-enriched glucose (1- and 2-{sup 13}C) as the carbon source in bacterial expression systems. Using this strategy, multiple sites in side chains, including aromatics, become site-selectively labeled and suitable for relaxation studies. Here we systematically investigate the use of site-selectively {sup 13}C-enriched erythrose (1-, 2-, 3- and 4-{sup 13}C) as a suitable precursor for {sup 13}C labeled aromatic side chains. We quantify {sup 13}C incorporation in nearly all sites in all 20 amino acids and compare the results to glucose based labeling. In general the erythrose approach results in more selective labeling. While there is only a minor gain for phenylalanine and tyrosine side-chains, the {sup 13}C incorporation level for tryptophan is at least doubled. Additionally, the Phe ζ and Trp η2 positions become labeled. In the aliphatic side chains, labeling using erythrose yields isolated {sup 13}C labels for certain positions, like Ile β and His β, making these sites suitable for dynamics studies. Using erythrose instead of glucose as a source for site-selective {sup 13}C labeling enables unique or superior labeling for certain positions and is thereby expanding the toolbox for customized isotope labeling of amino-acid side-chains.

  5. A comparison of quantitative methods for clinical imaging with hyperpolarized (13)C-pyruvate.

    Science.gov (United States)

    Daniels, Charlie J; McLean, Mary A; Schulte, Rolf F; Robb, Fraser J; Gill, Andrew B; McGlashan, Nicholas; Graves, Martin J; Schwaiger, Markus; Lomas, David J; Brindle, Kevin M; Gallagher, Ferdia A

    2016-04-01

    Dissolution dynamic nuclear polarization (DNP) enables the metabolism of hyperpolarized (13)C-labelled molecules, such as the conversion of [1-(13)C]pyruvate to [1-(13)C]lactate, to be dynamically and non-invasively imaged in tissue. Imaging of this exchange reaction in animal models has been shown to detect early treatment response and correlate with tumour grade. The first human DNP study has recently been completed, and, for widespread clinical translation, simple and reliable methods are necessary to accurately probe the reaction in patients. However, there is currently no consensus on the most appropriate method to quantify this exchange reaction. In this study, an in vitro system was used to compare several kinetic models, as well as simple model-free methods. Experiments were performed using a clinical hyperpolarizer, a human 3 T MR system, and spectroscopic imaging sequences. The quantitative methods were compared in vivo by using subcutaneous breast tumours in rats to examine the effect of pyruvate inflow. The two-way kinetic model was the most accurate method for characterizing the exchange reaction in vitro, and the incorporation of a Heaviside step inflow profile was best able to describe the in vivo data. The lactate time-to-peak and the lactate-to-pyruvate area under the curve ratio were simple model-free approaches that accurately represented the full reaction, with the time-to-peak method performing indistinguishably from the best kinetic model. Finally, extracting data from a single pixel was a robust and reliable surrogate of the whole region of interest. This work has identified appropriate quantitative methods for future work in the analysis of human hyperpolarized (13)C data. © 2016 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.

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

    Science.gov (United States)

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

    2011-07-13

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

  7. Normal state magnetic behavior of (U/sub 1-x/RE/sub x/)Be13 pseudobinaries

    International Nuclear Information System (INIS)

    Zirngiebl, E.; Thompson, J.D.; Smith, J.L.; Fisk, Z.

    1987-01-01

    Any impurity doping seems to modify the low temperature properties of UBe 13 in a way rather unusual compared to normal superconductors. So far, however, little attention has been paid to the modification of the normal state properties of impurity doped UB 13 . We have investigated the normal state magnetic behavior of impurity doped (U/sub 1-x/RE/sub x/)Be 13 pseudobinaries (RE = Th, Y, La, Lu, Sc) in the temperature range between 2 K and 380 K for impurity concentrations x ≤ 0.05 to see if there are correlations with T/sub c/(x)

  8. Nuclear Legislation in OECD and NEA Countries. Regulatory and Institutional Framework for Nuclear Activities - United States

    International Nuclear Information System (INIS)

    2015-01-01

    Agriculture; Department of Commerce; Department of Defense - DOD; Department of Health and Human Services - DHHS; Department of the Interior; Department of State); B. Other federal agencies and offices: (Federal Emergency Management Agency - FEMA; National Aeronautics and Space Administration - NASA; Tennessee Valley Authority - TVA; White House offices); C. Semi-public agencies (American National Standards Institute - ANSI; National Academy of Sciences - NAS; National Council on Radiation Protection and Measurement - NCRP; National Nuclear Data Center)

  9. State of Nevada, Agency for Nuclear Projects/Nuclear Waste Project Office narrative report, January 1992

    International Nuclear Information System (INIS)

    1992-01-01

    The Agency for Nuclear Projects/Nuclear Waste Project Office (NWPO) is the State of Nevada agency designated by State law to monitor and oversee US Department of Energy (DOE) activities relative to the possible siting, construction, operation and closure of a high-level nuclear waste repository at Yucca Mountain and to carry out the State of Nevada's responsibilities under the Nuclear Waste Policy Act of 1982. During the reporting period the NWPO continued to work toward the five objectives designed to implement the Agency's oversight responsibilities: (1) Assure that the health and safety of Nevada's citizens are adequately protected with regard to any federal high-level radioactive waste program within the State; (2) Take the responsibilities and perform the duties of the State of Nevada as described in the Nuclear Waste Policy Act of 1982 (Public Law 97-425) and the Nuclear Waste Policy Amendments Act of 1987; (3) Advise the Governor, the State Commission on Nuclear Projects and the Nevada State Legislature on matters concerning the potential disposal of high-level radioactive waste in the State; (4) Work closely and consult with affected local governments and State agencies; (5) Monitor and evaluate federal planning and activities regarding high-level radioactive waste disposal. Plan and conduct independent State studies regarding the proposed repository

  10. Ab initio/GIAO-CCSD(T) (13)C NMR study of the rearrangement and dynamic aspects of rapidly equilibrating tertiary carbocations, C6H13(+) and C7H15(+).

    Science.gov (United States)

    Olah, George A; Prakash, G K Surya; Rasul, Golam

    2016-01-05

    The rearrangement pathways of the equilibrating tertiary carbocations, 2,3-dimethyl-2-butyl cation (C6H13(+), 1), 2,3,3-trimethyl-2-butyl cation (C7H15(+), 5) and 2,3-dimethyl-2-pentyl cation (C7H15(+), 8 and 9) were investigated using the ab initio/GIAO-CCSD(T) (13)C NMR method. Comparing the calculated and experimental (13)C NMR chemical shifts of a series of carbocations indicates that excellent prediction of δ(13)C could be achieved through scaling. In the case of symmetrical equilibrating cations (1 and 5) the Wagner-Meerwein 1,2-hydride and 1,2-methide shifts, respectively, produce the same structure. This indicates that the overall (13)C NMR chemical shifts are conserved and independent of temperature. However, in the case of unsymmetrical equilibrating cations (8 and 9) the Wagner-Meerwein shift produces different tertiary structures, which have slightly different thermodynamic stabilities and, thus, different spectra. At the MP4(SDTQ)/cc-pVTZ//MP2/cc-pVTZ + ZPE level structure 8 is only 90 calories/mol more stable than structure 9. Based on computed (13)C NMR chemical shift calculations, mole fractions of these isomers were determined by assuming the observed chemical shifts are due to the weighted average of the chemical shifts of the static ions. © 2015 Wiley Periodicals, Inc.

  11. Proceedings of NUCLEAR 2013 the 6th annual international conference on sustainable development through nuclear research and education. Part 1/3

    International Nuclear Information System (INIS)

    Constantin, Marin; Turcu, Ilie

    2013-01-01

    The proceedings of the NUCLEAR 2013 international conference on sustainable development through nuclear research and education held at INR-Pitesti on May, 2-24 2013 contain 79 communications presented in two plenary sessions (6 and 8 talks, respectively) and three sections addressing the themes of Nuclear energy, Environmental protection, and Sustainable development . In turn these sections are addressing the following items: Section 1.1 - Nuclear Technology and Materials (33 papers); Section 1.2 Nuclear Safety and Sever Accidents (16 papers); 1.3 Nuclear Reactors and Gen IV (20 papers); 2.1 Radioactive Waste Management (13 papers); 2.2 Radioprotection and 2.3 Air, Water, Soil Protection (17 papers); 3.1 Polices and Strategies in Nuclear Research (0 papers); 3.2 International Partnership for a Sustainable Development (2 papers); 3.3 Education, Continuous Formation and Knowledge Transfer (1 papers). These papers are presented as abstracts in 'Nuclear 2013 - Book of Abstracts', separately processed

  12. Proceedings of NUCLEAR 2015 the 8th annual international conference on sustainable development through nuclear research and education. Part 1/3

    International Nuclear Information System (INIS)

    Constantin, Marin; Turcu, Ilie

    2015-01-01

    The proceedings of the NUCLEAR 2015 the 8"t"h annual international conference on sustainable development through nuclear research and education. Part 1/3 held at INR-Pitesti on May, 27-29 contain 62 communications presented in two plenary sessions and three sections addressing the themes of Nuclear energy, Environmental protection and Sustainable development. In turn these sections are addressing the following items: Section 1.1 Nuclear safety and severe accidents (7 papers); Section 1.2 Nuclear reactors and gen. IV (5 papers); Section 1.3 Nuclear technology and materials (19 papers); Section 2.1 Radioprotection & air, water and soil protection (1 paper); Section 2.2 Radioactive waste management (9 papers); Section 3.1 policies and strategies in nuclear research (1 paper); Section 3.2 Education, training and knowledge management (16 papers); Section 3.3 International partnership for a sustainable development (4 papers). These papers are presented as abstracts in 'Nuclear 2015 - Book of Abstracts', separately processed

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

    International Nuclear Information System (INIS)

    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. 13 C NMR spectroscopy was used to monitor shunt activity by determination of the ratios of [ 13 C-4] to [ 13 C-5]-glutamate, [ 13 C-3] to [ 13 C-2]-alanine or [ 13 C-3] to [ 13 C-2]-lactate produced when [ 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 13 C fractional enrichments of C4 and C5-glutamate as a function of shunt activity and on the signal-to- noise ratio acquired in 13 C NMR human studies from the current literature

  14. 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.

  15. {gamma} decay of spin-isospin states in {sup 13}N via ({sup 3}He, t{gamma}) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Ihara, F; Akimune, H; Daito, I; Fujimura, H; Fujiwara, M; Inomata, T; Ishibashi, K; Yoshida, H [Osaka Univ., Ibaraki (Japan). Research Center for Nuclear Physics; Fujita, Y

    1998-03-01

    Spin-isospin states in {sup 13}N have been studied by means of the {sup 13}C ({sup 3}He,t) reaction at and near zero degree, at E({sup 3}He)=450 MeV. Decayed {gamma}-rays from each state were measured at backward angle in coincidence with the ejectile tritons. The branching ratio of {gamma} decay for some of spin-isospin states were determined and were compared to those from previous data. (author)

  16. {sup 13}C-NMR studies on disulfide bond isomerization in bovine pancreatic trypsin inhibitor (BPTI)

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Mitsuhiro [Kumamoto University, Department of Structural BioImaging, Faculty of Life Sciences (Japan); Miyanoiri, Yohei [Nagoya University, Structural Biology Research Center, Graduate School of Science (Japan); Terauchi, Tsutomu [Tokyo Metropolitan University, Graduate School of Science and Engineering (Japan); Kainosho, Masatsune, E-mail: kainosho@tmu.ac.jp [Nagoya University, Structural Biology Research Center, Graduate School of Science (Japan)

    2016-09-15

    Conformational isomerization of disulfide bonds is associated with the dynamics and thus the functional aspects of proteins. However, our understanding of the isomerization is limited by experimental difficulties in probing it. We explored the disulfide conformational isomerization of the Cys14–Cys38 disulfide bond in bovine pancreatic trypsin inhibitor (BPTI), by performing an NMR line-shape analysis of its Cys carbon peaks. In this approach, 1D {sup 13}C spectra were recorded at small temperature intervals for BPTI samples selectively labeled with site-specifically {sup 13}C-enriched Cys, and the recorded peaks were displayed in the order of the temperature after the spectral scales were normalized to a carbon peak. Over the profile of the line-shape, exchange broadening that altered with temperature was manifested for the carbon peaks of Cys14 and Cys38. The Cys14–Cys38 disulfide bond reportedly exists in equilibrium between a high-populated (M) and two low-populated states (m{sub c14} and m{sub c38}). Consistent with the three-site exchange model, biphasic exchange broadening arising from the two processes was observed for the peak of the Cys14 α-carbon. As the exchange broadening is maximized when the exchange rate equals the chemical shift difference in Hz between equilibrating sites, semi-quantitative information that was useful for establishing conditions for {sup 13}C relaxation dispersion experiments was obtained through the carbon line-shape profile. With respect to the m{sub c38} isomerization, the {sup 1}H-{sup 13}C signals at the β-position of the minor state were resolved from the major peaks and detected by exchange experiments at a low temperature.

  17. Nuclear design report for Kori nuclear power plant unit 1, cycle 13

    Energy Technology Data Exchange (ETDEWEB)

    Zee, Sung Kyun; Moon, Bok Ja; Cho, Byeong Ho; Jung, Yil Sup [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1993-04-01

    This report presents nuclear design calculations for cycle 13 of Kori unit 1. Information is given on fuel loading, power density distributions, reactivity coefficients, control rod worths and operational limits. In addition, the report contains all necessary data for the startup tests including predicted values for the comparison with the measured data. The reload consists of 44 KOFA`s enriched by nominally 3.70 w/o U{sub 235}. Among the KOFA`s, 16 fuel assemblies contain gadolinia rods. The fuel assemblies in the core are arranged in a low leakage loading pattern. The cycle length of cycle 13 amounts to 355 EFPD corresponding to a cycle burnup of 13240 MWD/MTU. (Author) 8 refs., 55 figs., 16 tabs.

  18. Carbon-13 kinetic isotope effects in the decarbonylations of lactic acid containing 13C at the natural abundance level

    International Nuclear Information System (INIS)

    Zielinski, M.; Czarnota, G.; Papiernik-Zielinska, H.

    1992-01-01

    The 13 C kinetic isotope fractionation in the decarbonylation of lactic acid of natural isotopic composition by sulfuric acid has been studied in the temperature range of 20-80 deg C. The 13 C (1) isotope separation in the decarbonylation of lactic acid by concentrated sulfuric acid depends strongly on the temperature above 40 deg C. Below this temperature the 13 C isotope effect in the decarbonylation of lactic acid by concentrated sulfuric acid is normal similarly as has been found in the decarbonylation of lactic [1- 14 C] acid. The experimental values of k (12C) /k (13C) ratios of isotopic rate constants for 12 C and 13 C are close to, but slightly higher than theoretical 13 C-kinetic isotope effects calculated (neglecting tunneling) under the asumption that the C (1) -OH bond is broken in the rate-controlling step of the dehydration reaction. Dilution of concentrated sulfuric acid with water up to 1.4 molar (H 2 O)/(H 2 SO 4 ) ratio caused the increase of the 13 C isotope fractionation from 1.0273 found in concentrated sulfuric acid at 80.5 deg C to 1.0536±0.0008 (at 80.6 deg C). A discussion of the abnormally high temperature dependence of 14 C and 13 C isotope fractionation in this reaction and the discussion of the problem of relative 14 C/ 13 C kinetic isotope effects is given. (author) 18 refs.; 2 tabs

  19. 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.

  20. Nuclear ground state

    International Nuclear Information System (INIS)

    Negele, J.W.

    1975-01-01

    The nuclear ground state is surveyed theoretically, and specific suggestions are given on how to critically test the theory experimentally. Detailed results on 208 Pb are discussed, isolating several features of the charge density distributions. Analyses of 208 Pb electron scattering and muonic data are also considered. 14 figures

  1. 13C and 31P NMR [Nuclear Magnetic Resonance] studies of prostate tumor metabolism

    International Nuclear Information System (INIS)

    Sillerud, L.O.; Halliday, K.R.; Freyer, J.P; Griffey, R.H.; Fenoglio-Preiser, C.

    1989-01-01

    The current research on prostate cancer by NMR spectroscopy and microscopy will most significantly contribute to tumor diagnosis and characterization only if sound biochemical models of tumor metabolism are established and tested. Prior searches focused on universal markers of malignancy, have to date, revealed no universal markers by any method. It is unlikely that NMRS will succeed where other methods have failed, however, NMR spectroscopy does provide a non-invasive means to analyze multiple compounds simultaneously in vivo. In order to fully evaluate the ability of NMRS to differentiate non-malignant from malignant tissues it is necessary to determine sufficient multiple parameters from specific, well-diagnosed, histological tumor types that, in comparison to normal tissue and non-neoplastic, non-normal pathologies from which the given neoplasm must be differentiated, one has enough degrees of freedom to make a mathematically and statistically significant determination. Confounding factors may consist of tumor heterogeneity arising from regional variations in differentiation, ischemia, necrosis, hemorrhage, inflammation and the presence of intermingled normal tissue. One related aspect of our work is the development of { 13 C}- 1 H metabolic imaging of 13 C for metabolic characterization, with enhanced spatial localization (46). This should markedly extend the range of potential clinical NMR uses because the spatial variation in prostate metabolism may prove to be just as important in tumor diagnoses as bulk (volume-averaged) properties themselves. It is our hope that NMRS and spectroscopic imaging will reveal a sound correlation between prostate metabolism and tumor properties that will be clinically straightforward and useful for diagnosis

  2. IAEA Completes Nuclear Security Review Mission in United States

    International Nuclear Information System (INIS)

    2013-01-01

    Full text: A team of nuclear security experts led by the International Atomic Energy Agency (IAEA) today completed a mission to review nuclear security practices of civil nuclear facilities licensed by the United States Nuclear Regulatory Commission (NRC). Conducted at the U.S. Government's request, the two-week International Physical Protection Advisory Service (IPPAS) mission reviewed the United States' nuclear security-related legislative and regulatory framework. As part of this work, the IPPAS team, led by John O'Dacre of Canada and comprising nine experts from eight IAEA Member States, met with NRC officials and reviewed the physical protection systems at the Center for Neutron Research (NCNR) at the National Institute of Standards and Technology. The IPPAS team concluded that nuclear security within the U.S. civil nuclear sector is robust and sustainable and has been significantly enhanced in recent years. The team identified a number of good practices in the nation's nuclear security regime and at the NCNR. The IPPAS team also made a recommendation and some suggestions for the continuing improvement of nuclear security overall. The mission in the United States was the 60th IPPAS mission organized by the IAEA. 'Independent international peer reviews such as IAEA IPPAS missions are increasingly being recognized for their value as a key component for exchanges of views and advice on nuclear security measures', said Khammar Mrabit, Director of the IAEA Office of Nuclear Security. 'The good practices identified during this mission will contribute to the continuous improvements of nuclear security in other Member States'. The IPPAS team provided a draft report to the NRC and will submit a final report soon. Because it contains security-related information about a specific nuclear site, IPPAS reports are not made public. 'The IPPAS programme gives us a chance to learn from the experience and perspective of our international partners', said NRC Chairman Allison M

  3. Book of abstracts of 13. national conference on nuclear structure and 9. symposium on 'nuclear structure and quantum mechanics'

    International Nuclear Information System (INIS)

    2010-07-01

    13. national conference on nuclear structure and 9. symposium on 'nuclear structure and quantum mechanics' was held by China Nuclear Physics Society in Chifeng, 25 to 30 July, 2010. The proceedings collects the abstracts of 102 articles

  4. Preparation of 15N-13C-fulminic acid

    International Nuclear Information System (INIS)

    Wilmes, R.; Winnewisser, M.

    1993-01-01

    The precursor for the title compound was prepared in a three-step synthesis. The 13 C-label was incorporated in the first step employing 2- 13 C-ethyl acetate and the 15 N-label in the last step, using 15 N-sodium nitrite. Upon pyrolysis the precursor forms three fragments, one of them being the title compound. (Author)

  5. 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...

  6. Motions and electrostatic interactions in natural and semisynthetic myoglobins: a carbon-13 nuclear magnetic resonance study

    International Nuclear Information System (INIS)

    Maskalick, D.G.

    1984-01-01

    It is expected that the internal motions of amino acid side chains and protein backbone segments influence and are in turn affected by charge-charge and related interactions, steric constraints, hydrophobic forces, and hydrogen bonding. As an initial test of this theory 13 C-enriched glycine, alanine, and isoleucine have been substituted for the amino terminal valine of sperm whale myoglobin using semisynthetic techniques. 13 C-NMR has been used to analyze the motions of the side chain and the protonation state of the alpha amino group as a function of pH. The addition of a single methyl group to the side chain can alter the alpha amino pK value by as much as 0.3 pH units indicating a delicately balanced set of change-charge interactions between the alpha amino group and the rest of the protein. Further evidence in support of the state theory was found upon examination of the internal motions of seven of nine isoleucine vectors. These motions were extracted from natural abundance 13 C-NMR relaxation data. The results suggest a strong possibility that concerted motions are important. Also, an increase in temperature from 32 0 C to 52 0 C leads to an electrostatically driven tightening of the myoglobin structure as evidenced by no significant increase in motion amplitude of most of the vectors

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

    Science.gov (United States)

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

    2013-08-01

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

  8. Assessing the optimism-pessimism debate: Nuclear proliferation, nuclear risks, and theories of state action

    International Nuclear Information System (INIS)

    Busch, Nathan Edward

    2001-01-01

    This dissertation focuses on the current debate in international relations literature over the risks associated with the proliferation of nuclear weapons. On this subject, IR scholars are divided into roughly two schools: proliferation 'optimists,' who argue that proliferation can be beneficial and that its associated hazards are at least surmountable, and proliferation 'pessimists,' who believe the opposite. This debate centers upon a theoretical disagreement about how best to explain and predict the behavior of states. Optimists generally ground their arguments on rational deterrence theory and maintain that nuclear weapons can actually increase stability among states, while pessimists often ground their arguments on 'organization theory,' which contends that organizational, bureaucratic, and other factors prevent states from acting rationally. A major difficulty with the proliferation debate, however, is that both sides tend to advance their respective theoretical positions without adequately supporting them with solid empirical evidence. This dissertation detailed analyses of the nuclear programs in the United States, Russia, China, India, and Pakistan to determine whether countries with nuclear weapons have adequate controls over their nuclear arsenals and tissue material stockpiles (such as highly enriched uranium and plutonium). These case studies identify the strengths and weaknesses of different systems of nuclear controls and help predict what types of controls proliferating states are likely to employ. On the basis of the evidence gathered from these cases, this dissertation concludes that a further spread of nuclear weapons would tend to have seriously negative effects on international stability by increasing risks of accidental, unauthorized, or inadvertent use of nuclear weapons and risks of thefts of fissile materials for use in nuclear or radiological devices by aspiring nuclear states or terrorist groups. (author)

  9. 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...

  10. Synthesis of specifically 15N- and 13C-labeled antitumor (2-Haloethyl)nitrosoureas. The study of their conformations in solution by nitrogen-15 and carbon-13 nuclear magnetic resonance and evidence for stereoelectronic control in their aqueous decomposition

    International Nuclear Information System (INIS)

    Lown, J.W.; Chauhan, S.M.S.

    1981-01-01

    The synthesis of certain specifically 15 N, 13 C, and 2 H isotope labeled 1-(2-chloroethyl)-3-alkyl-1-nitrosoureas (CENUs) is described. Spectroscopic examination of CENUs and their isotope-labeled counterparts by 1 H, 15 N, and 13 C NMR and infrared spectra indicates that they adopt preferred conformations in nonpolar aprotic solvents in which the NO group is aligned toward the 2-chloroethyl group. The result is in accord with the conformation of MeCCNU in the crystalline state derived from X-ray diffraction. The chemical shifts and coupling constants in the CENUs change with both solvent polarity and basicity. In aqueous phosphate buffer there is evidence for the formation of a tetrahedral intermediate, the conformation of which alters according to the reaction conditions and ultimately controls the formation of the aqueous decomposition products of CENUs. This is revealed most clearly by 13 C NMR of carbonyl- 13 C- and nitroso- 15 N-labeled BCNU and CCNU where two distinct 15 N-coupled 13 C doublets with different chemical shifts are observed. The rate of conformational change is comparable with the rate of decomposition of CENUs (via the second conformer) and may therefore represent the critical initial step of the latter process in vivo. The intermediacy of the postulated tetrahedral intermediates for CENUs is supported by observed 18 O exchange into the carbonyl group in 18 O-enriched water. Consideration of the conformations of the intermediates and of the alignment of the heteroatom lone pairs provides a satisfactory interpretation of the reactions of CENUs in aqueous solution as well as their pH dependence in terms of strict steroelectronic control and accounts for the formation of the observed products

  11. Metabolic Characterization of Acutely Isolated Hippocampal and Cerebral Cortical Slices Using [U-13C]Glucose and [1,2-13C]Acetate as Substrates.

    Science.gov (United States)

    McNair, Laura F; Kornfelt, Rasmus; Walls, Anne B; Andersen, Jens V; Aldana, Blanca I; Nissen, Jakob D; Schousboe, Arne; Waagepetersen, Helle S

    2017-03-01

    Brain slice preparations from rats, mice and guinea pigs have served as important tools for studies of neurotransmission and metabolism. While hippocampal slices routinely have been used for electrophysiology studies, metabolic processes have mostly been studied in cerebral cortical slices. Few comparative characterization studies exist for acute hippocampal and cerebral cortical slices, hence, the aim of the current study was to characterize and compare glucose and acetate metabolism in these slice preparations in a newly established incubation design. Cerebral cortical and hippocampal slices prepared from 16 to 18-week-old mice were incubated for 15-90 min with unlabeled glucose in combination with [U- 13 C]glucose or [1,2- 13 C]acetate. Our newly developed incubation apparatus allows accurate control of temperature and is designed to avoid evaporation of the incubation medium. Subsequent to incubation, slices were extracted and extracts analyzed for 13 C-labeling (%) and total amino acid contents (µmol/mg protein) using gas chromatography-mass spectrometry and high performance liquid chromatography, respectively. Release of lactate from the slices was quantified by analysis of the incubation media. Based on the measured 13 C-labeling (%), total amino acid contents and relative activity of metabolic enzymes/pathways, we conclude that the slice preparations in the current incubation apparatus exhibited a high degree of metabolic integrity. Comparison of 13 C-labeling observed with [U- 13 C]glucose in slices from cerebral cortex and hippocampus revealed no significant regional differences regarding glycolytic or total TCA cycle activities. On the contrary, results from the incubations with [1,2- 13 C]acetate suggest a higher capacity of the astrocytic TCA cycle in hippocampus compared to cerebral cortex. Finally, we propose a new approach for assessing compartmentation of metabolite pools between astrocytes and neurons using 13 C-labeling (%) data obtained from

  12. Development of Risk Assessment Methodology for State's Nuclear Security Regime

    International Nuclear Information System (INIS)

    Jang, Sung Soon; Seo, Hyung Min; Lee, Jung Ho; Kwak, Sung Woo

    2011-01-01

    Threats of nuclear terrorism are increasing after 9/11 terrorist attack. Treats include nuclear explosive device (NED) made by terrorist groups, radiological damage caused by a sabotage aiming nuclear facilities, and radiological dispersion device (RDD), which is also called 'dirty bomb'. In 9/11, Al Qaeda planed to cause radiological consequences by the crash of a nuclear power plant and the captured airplane. The evidence of a dirty bomb experiment was found in Afganistan by the UK intelligence agency. Thus, the international communities including the IAEA work substantial efforts. The leaders of 47 nations attended the 2010 nuclear security summit hosted by President Obama, while the next global nuclear summit will be held in Seoul, 2012. Most states established and are maintaining state's nuclear security regime because of the increasing threat and the international obligations. However, each state's nuclear security regime is different and depends on the state's environment. The methodology for the assessment of state's nuclear security regime is necessary to design and implement an efficient nuclear security regime, and to figure out weak points. The IAEA's INPRO project suggests a checklist method for State's nuclear security regime. The IAEA is now researching more quantitative methods cooperatively with several countries including Korea. In this abstract, methodologies to evaluate state's nuclear security regime by risk assessment are addressed

  13. {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.

  14. Dynamic nuclear polarization of nucleic acid with endogenously bound manganese

    Energy Technology Data Exchange (ETDEWEB)

    Wenk, Patricia [University of Tübingen, Werner Siemens Imaging Center and Department of Preclinical Imaging and Radiopharmacy (Germany); Kaushik, Monu; Richter, Diane [Goethe University, Institute of Physical und Theoretical Chemistry, Institute of Biophysical Chemistry und Center for Biomolecular Magnetic Resonance (BMRZ) (Germany); Vogel, Marc; Suess, Beatrix [Technical University Darmstadt, Department of Biology (Germany); Corzilius, Björn, E-mail: corzilius@em.uni-frankfurt.de [Goethe University, Institute of Physical und Theoretical Chemistry, Institute of Biophysical Chemistry und Center for Biomolecular Magnetic Resonance (BMRZ) (Germany)

    2015-09-15

    We report the direct dynamic nuclear polarization (DNP) of {sup 13}C nuclei of a uniformly [{sup 13}C,{sup 15}N]-labeled, paramagnetic full-length hammerhead ribozyme (HHRz) complex with Mn{sup 2+} where the enhanced polarization is fully provided by the endogenously bound metal ion and no exogenous polarizing agent is added. A {sup 13}C enhancement factor of ε = 8 was observed by intra-complex DNP at 9.4 T. In contrast, “conventional” indirect and direct DNP experiments were performed using AMUPol as polarizing agent where we obtained a {sup 1}H enhancement factor of ε ≈ 250. Comparison with the diamagnetic (Mg{sup 2+}) HHRz complex shows that the presence of Mn{sup 2+} only marginally influences the (DNP-enhanced) NMR properties of the RNA. Furthermore two-dimensional correlation spectra ({sup 15}N–{sup 13}C and {sup 13}C–{sup 13}C) reveal structural inhomogeneity in the frozen, amorphous state indicating the coexistence of several conformational states. These demonstrations of intra-complex DNP using an endogenous metal ion as well as DNP-enhanced MAS NMR of RNA in general yield important information for the development of new methods in structural biology.

  15. The nuclear equation of state

    International Nuclear Information System (INIS)

    Kahana, S.

    1986-01-01

    The role of the nuclear equation of state in determining the fate of the collapsing cores of massive stars is examined in light of both recent theoretical advances in this subject and recent experimental measurements with relativistic heavy ions. The difficulties existing in attempts to bring the softer nuclear matter apparently required by the theory of Type II supernovae into consonance with the heavy ion data are discussed. Relativistic mean field theory is introduced as a candidate for derivation of the equation of state, and a simple form for the saturation compressibility is obtained. 28 refs., 4 figs., 1 tab

  16. The nuclear equation of state

    Energy Technology Data Exchange (ETDEWEB)

    Kahana, S.

    1986-01-01

    The role of the nuclear equation of state in determining the fate of the collapsing cores of massive stars is examined in light of both recent theoretical advances in this subject and recent experimental measurements with relativistic heavy ions. The difficulties existing in attempts to bring the softer nuclear matter apparently required by the theory of Type II supernovae into consonance with the heavy ion data are discussed. Relativistic mean field theory is introduced as a candidate for derivation of the equation of state, and a simple form for the saturation compressibility is obtained. 28 refs., 4 figs., 1 tab.

  17. Freshwater Mussel Shell δ13C Values as a Proxy for δ13CDIC in a Polluted, Temperate River

    Science.gov (United States)

    Graniero, L. E.; Gillikin, D. P.; Surge, D. M.

    2017-12-01

    Freshwater mussel shell δ13C values have been examined as an indicator of ambient δ13C composition of dissolved inorganic carbon (DIC) in temperate rivers. However, shell δ13C values may be obscured by the assimilation of respired, metabolic carbon (CM) derived from the organism's diet. Water δ18O and δ13CDIC values were collected fortnightly from August 2015 through July 2017 from three sites (one agricultural, one downstream of a wastewater treatment plant, one urban) in the Neuse River, NC to test the reliability of Elliptio complanata shell δ13C values as a proxy for δ13CDIC values. Muscle, mantle, gill, and stomach δ13C values were analyzed to approximate the %CM incorporated into the shell. All tissue δ13C values were within 2‰ of each other, which equates to a ±1% difference in calculated %CM. As such, muscle tissue δ13C values will be used for calculating the %CM, because they have the slowest turnover rate of the tissues sampled. Water temperature and δ18O values were used to calculate predicted aragonite shell δ18O­ values (δ18O­ar) based on the aragonite-water fractionation relationship. To assign dates to each shell microsample, predicted δ18O­ar values were compared to high-resolution serially sampled shell values. Consistent with previous studies, E. complanata cease growth in winter when temperatures are below about 12ºC. Preliminary results indicate that during the growing season, shell δ13C values are lower than expected equilibrium values, reflecting the assimilation of 15% CM, on average. Shell δ13C values are not significantly different than δ13CDIC values, but do not capture the full range of δ13CDIC values during each growing season. Thus, δ13C values of E. complanata shells can be used to reliably reconstruct past δ13CDIC values within 2‰ of coeval values. Further research will investigate how differing land-use affects the relationship between shell δ13C, CM, and δ13CDIC values.

  18. Nuclear magnetic resonance of D(-)-α-amino-benzyl penicillin

    International Nuclear Information System (INIS)

    Aguiar, Monica R.M.P.; Gemal, Andre L.; San Gil, Rosane A.S.; Menezes, Sonia M.C.

    1995-01-01

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

  19. Optically enhanced nuclear cross polarization in acridine-doped fluorene

    Energy Technology Data Exchange (ETDEWEB)

    Oshiro, C.M.

    1982-06-01

    The objective of this work has been to create large polarizations of the dilute /sup 13/C nuclei in the solid state. The idea was to create /sup 1/H polarizations larger than Boltzmann and to use the proton enhanced nuclear induction spectroscopy cross polarization technique to then transfer this large polarization to the /sup 13/C spin system. Optical Nuclear Polarization (ONP) of acridine-doped fluorene single crystals was studied. In addition, ONP of powdered samples of the acridine-doped fluorene was studied. In general, many compounds do not crystallize easily or do not form large crystals suitable for NMR experiments. Powdered, amorphous and randomly dispersed samples are generally far more readily available than single crystals. One objective of this work has been to (first) create large /sup 1/H polarizations. Although large optical proton polarizations in single crystals have been reported previously, optically generated polarizations in powdered samples have not been reported. For these reasons, ONP studies of powdered samples of the acridine-doped fluorene were also undertaken. Using ONP in combination with the proton enhanced nuclear induction spectroscopy experiment, large /sup 13/C polarizations have been created in fluorene single crystals. These large /sup 13/C polarizations have permitted the determination of the seven incongruent chemical shielding tensors of the fluorene molecule. Part 2 of this thesis describes the proton enhanced nuclear induction spectroscopy experiment. Part 3 describes the ONP experiment. Part 4 is a description of the experimental set-up. Part 5 describes the data analysis for the determination of the chemical shielding tensors. Part 6 presents the results of the ONP experiments performed in this work and the chemical shielding tensors determined.

  20. Optically enhanced nuclear cross polarization in acridine-doped fluorene

    International Nuclear Information System (INIS)

    Oshiro, C.M.

    1982-06-01

    The objective of this work has been to create large polarizations of the dilute 13 C nuclei in the solid state. The idea was to create 1 H polarizations larger than Boltzmann and to use the proton enhanced nuclear induction spectroscopy cross polarization technique to then transfer this large polarization to the 13 C spin system. Optical Nuclear Polarization (ONP) of acridine-doped fluorene single crystals was studied. In addition, ONP of powdered samples of the acridine-doped fluorene was studied. In general, many compounds do not crystallize easily or do not form large crystals suitable for NMR experiments. Powdered, amorphous and randomly dispersed samples are generally far more readily available than single crystals. One objective of this work has been to (first) create large 1 H polarizations. Although large optical proton polarizations in single crystals have been reported previously, optically generated polarizations in powdered samples have not been reported. For these reasons, ONP studies of powdered samples of the acridine-doped fluorene were also undertaken. Using ONP in combination with the proton enhanced nuclear induction spectroscopy experiment, large 13 C polarizations have been created in fluorene single crystals. These large 13 C polarizations have permitted the determination of the seven incongruent chemical shielding tensors of the fluorene molecule. Part 2 of this thesis describes the proton enhanced nuclear induction spectroscopy experiment. Part 3 describes the ONP experiment. Part 4 is a description of the experimental set-up. Part 5 describes the data analysis for the determination of the chemical shielding tensors. Part 6 presents the results of the ONP experiments performed in this work and the chemical shielding tensors determined

  1. Responsibilities of the nuclear-weapon states

    International Nuclear Information System (INIS)

    Wang Jun

    1994-01-01

    The responsibilities of Nuclear Weapon States are presented by a straightforward analysis together with the ways in which they could fulfill them. The complete undertaking of all the commitments by the Nuclear Weapon States may take a long time. However they do not have a single excuse to neglect such a historic opportunity to do their best to provide a genuinely secure world environment for the international community, of which they too are members

  2. Progress in fission product nuclear data. No. 13

    International Nuclear Information System (INIS)

    Lammer, M.

    1990-11-01

    This is the 13th issue of a report series published by the Nuclear Data Section of the IAEA. The types of activities included are measurements, compilations and evaluations of: Fission product yields (neutron induced and spontaneous fission), neutron reaction cross-sections of fission products, data related to the radioactive decay of fission products, delayed neutron data of fission products and bumped fission product data (decay heat, absorption, etc.). The first part of the report consists of unaltered original data which the authors have sent to IAEA/NDS. The second part contains some recent references relative to fission product nuclear data, which were not covered by the contributions submitted, and selected papers from conferences. Part 3 contains requirements for further measurements

  3. Preparation of Act on State Surveillance of Nuclear Safety of Nuclear Installations

    International Nuclear Information System (INIS)

    Kyncl, J.

    1983-01-01

    The Czechoslovak Government Decree no. 179 of June 1982 approved the principles underlying the first Czechoslovak legal norm to complexly resolve the problem of State surveillance of nuclear safety of nuclear installations. In the introduction the law will define the concept of nuclear safety of nuclear installations and will justify the reasons for which it has to be assured. The individual parts of the law will deal with the establishment of State surveillance of nuclear safety, the tasks of the Czechoslovak Atomic Energy Commission in this area, the control activity of Commission personnel, the measures taken against responsible organizations and personnel for failing to observe their duties, the obligations of bodies and organizations, and the cooperation between inspection bodies. (A.K.)

  4. Biosynthesis of quinolizidine alkaloids. Incorporation of [1-amino-15N, 1-13C] cadaverine into lupanine, 13-hydroxylupanine, and angustifoline

    International Nuclear Information System (INIS)

    Rana, J.; Robins, D.J.

    1985-01-01

    The labelling patterns in (+)-lupanine, (+)-13-hydroxylupanine, and (+)-angustifoline derived biosynthetically from [1-amino- 15 N,1- 13 C]-1,5-diaminopentane (cadaverine) have been established by 13 C n.m.r. spectroscopy. Three cadaverine units are incorporated to about the same extent into each of these three alkaloids. The presence of two doublets due to 13 C- 15 N coupling in the 13 C brace 1 H brace n.m.r. spectra associated with C-2 and C-15 of lupanine and 13-hydroxylupanine, and one 13 C- 15 N doublet at C-2 of angustifoline, indicate that two of the cadaverine units are converted into the outer rings of the tetracyclic quinolizidine alkaloids in a specific fashion. (author)

  5. 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.

  6. (13)C enrichment of the CO2 in breast milk and in the breath is rapidly modified by changes in the (13)C content of the diet.

    Science.gov (United States)

    Villalpando, Salvador; Del Prado, Martha; Cienfuego, Edith; Morales, Pedro

    2014-01-01

    C4 plants (e.g. corn and sugar cane) have greater (13)C enrichment than C3 plants (e.g. wheat and sugar beet). To assess whether (13)C enrichment of CO2 in the breath and breast milk of women on diets based on C3 and C4 foods changes from one diet to the other. Six breast-feeding women were studied at 5-6 months postpartum. They ate a controlled C4 diet on days 1 and 2 followed by a C3 diet on days 3 and 4. Diet duplicates, breast milk on days 2 and 4 and hourly breath samples were collected over 4 days. (13)C enrichment was measured by isotope-ratio mass spectrometry. Values of δ(13)C were calculated from the international PDBV standard (δ(13)CPDBV). Differences between means were compared by paired t test or t test for repeated measurements. δ(13)CPDBV values were significantly higher in the C4 diet than in the C3 diet composites (p value was greater on days 1 and 2 (range -15.4 to -13.2, respectively) and declined on days 3 and 4 (range -20.0 to -21.8, respectively, p value in the breath and breast milk fractions, which diminish rapidly on a C3 diet. Further studies focusing on individual nutrients are warranted.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bolo, Nicolas Robin [Univ. of California, Berkeley, CA (United States)

    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. 13C NMR spectroscopy was used to monitor shunt activity by determination of the ratios of [13C-4] to [13C-5]-glutamate, [13C-3] to [13C-2]-alanine or [13C-3] to [13C-2]-lactate produced when [13C-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 13C fractional enrichments of C4 and C5-glutamate as a function of shunt activity and on the signal-to- noise ratio acquired in 13C NMR human studies from the current literature.

  8. Nuclear magnetic resonance study of the effect of the addition of clay on polypropylene

    International Nuclear Information System (INIS)

    Nogueira, Regina F.; San Gil, Rosane A.S.; Tavares, Maria Ines B.

    2001-01-01

    Polypropylene (PP) samples and polypropylene (PP)/clay (M) composite prepared by melting mixing have been characterized by solution and solid state nuclear magnetic resonance spectroscopy (NMR). The monomer sequences distribution and the influence of time and temperature of mechanical mix on the modifications in the PP structure were investigated by 13 C solution NMR. The solid state NMR investigation showed that the 13 C routine spectra such as MAS and CPMAS allowed obtaining information on the molecular domains of chains, and also permits to evaluate the domains mobility. 29 Si and 27 Al solid state NMR were used to characterize the clay and the PP/M composite samples. The results showed that the heating and friction in the range of temperature and time used in the sample preparation did not affect the distribution of configurational sequence in the PP chains. The effect of clay in the PP/M composite structure could be detected, using both 13 C solution and in 29 Si solid state NMR spectra. (author)

  9. I and C upgrading at nuclear power plants

    International Nuclear Information System (INIS)

    Tamiri, A.

    2003-01-01

    Continuing the operation of existing nuclear power plants will help reduce the number of new base-load nuclear and fossil power plants that need to be built. Old nuclear power plants in Canada are operating with analog instrumentation and control systems. For a number of reasons, such as changes and improvements in the applicable standards and design, maintenance problems due to the lack of spares, technical obsolescence, the need to increase power production, availability, reliability and safety, and in order to reduce operation and maintenance costs, instrumentation and control upgrading at nuclear power plants in a cost effective manner should be considered the greatest priority. Failures of instrumentation and control (I and C) due to aging and obsolescence issues may have an immediate negative impact on plant reliability and availability and also affect long-term plant performance and safety. In today's competitive marketplace, power plants are under pressure to cut spending on maintenance while reducing the risk of equipment failure that could cause unplanned outage. To improve plant safety and availability, old nuclear power plants will require investment in new technologies that can improve the performance and reduce the costs of generation by addressing the long term reliability of systems by up-grading to modem digital instrumentation and control and optimization opportunities. Boiler drum level control at nuclear power plants is critical for both plant protection and equipment safety and applies equality to high and low levels of water within the boiler drum. Plant outage studies at Pickering Nuclear have identified boiler drum level control and feed water control systems as major contributors to plant unavailability. Ways to improve transient and steady state response, upgrading existing poor analog control systems for boiler level and feed-water control systems at Pickering Nuclear, with enhanced and robust controller will be discussed in this paper

  10. Study of the magnetic form factor of 13C by measurement of radiative pion capture at high momentum transfer: search for precursors to pion condensation

    International Nuclear Information System (INIS)

    Crowe, K.M.

    1982-01-01

    By studying radiative capture in flight, information can be obtained on the energy and momentum transfer dependence of nuclear transition densities containing the spin. These are of interest from a nuclear structure point of view, as well as in connection with discussions of exotic phenomena such as pion condensation and opalescence. This report presents preliminary results of measurements of 1 H(π - ,γ)n at T = 113 MeV and 13 C(π + ,γ) 13 N g.s. at T = 115 MeV. (Auth.)

  11. Status of nuclear engineering education in the United States

    International Nuclear Information System (INIS)

    Brown, G.J.

    2000-01-01

    Nuclear engineering education in the United States is reflective of the perceived health of the nuclear electric power industry within the country. Just as new commercial reactor orders have vanished and some power plants have shut down, so too have university enrollments shrunk and research reactors closed. This decline in nuclear trained specialists and the disappearance of the nuclear infrastructure is a trend that must be arrested and reversed if the United States is to have a workforce capable of caring for a nuclear power industry to not only meet future electric demand but to ensure that the over 100 existing plants, their supporting facilities and their legacy in the form of high level waste and facility clean-up are addressed. Additionally, the United States has an obligation to support and maintain its nuclear navy and other defence needs. And, lastly, if the United States is to have a meaningful role in the international use of nuclear power with regard to safety, non-proliferation and the environment, then it is imperative that the country continues to produce world-class nuclear engineers and scientists by supporting nuclear engineering education at its universities. The continued support of the federal government. and industry for university nuclear engineering and nuclear energy research and development is essential to sustain the nuclear infrastructure in the United States. Even with this support, and the continued excellent operation of the existing fleet of nuclear electric power plants, it is conceivable that nuclear engineering as an academic discipline may fall victim to poor communications and a tarnished public image. What is needed is a combination of federal and industrial support along with the creativity of the universities to expand their offerings to include more than power production. The objective is a positive message on careers in nuclear related fields, and recognition of the important role of nuclear energy in meeting the country

  12. The 12C/13C ratio in stellar atmospheres. VI. Five luminous cool stars

    International Nuclear Information System (INIS)

    Hinkle, K.H.; Lambert, D.L.; Snell, R.L.

    1976-01-01

    The isotopic abundance ratio, 12 C/ 13 C, is derived from the CO vibration rotation lines at 1.6 and 2.3 μ for five cool luminous stars by a simple curve-of-growth technique. A new analysis of CN lines at 8000 A is also described for α Sco and α Ori. Results derived independently from CO and CN are in agreement. Final results are 12 C/ 13 C=7 +- 2(α Ori), 12 +- 3(α Sco), 7 +- 3(β Peg), 25 +- 7(chi Cyg), 17 +- 4(α Her), and 7 +- 1.5(α Boo). The α Boo analysis provides a check on the CO curve-of-growth technique; the 12 C/ 13 C ratio from the 2.3 μ CO lines is in good agreement with the previously determined ratio from CN and CH lines

  13. Determination of the Tautomeric Equilibria of Pyridoyl Benzoyl -Diketones in the Liquid and Solid State through the use of Deuterium Isotope Effects on 1H and 13C NMR Chemical Shifts and Spin Coupling Constants

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  14. 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

  15. Thz Spectroscopy of 13C Isotopic Species of a "weed": Acetaldehyde

    Science.gov (United States)

    Margulès, L.; Motiyenko, R. A.; Guillemin, J.-C.

    2011-06-01

    Our studies of the isotopic species of 13C and D isotopologues of methyl formate (HCOOCH_3), have allowed the detection of more than 600 lines in Orion. This confirms that many observed U-lines are coming from isotopic species of one of the most abundant molecules in space. Since its first detection in 1976 in SgrB2 and in Orion A, acetaldehyde (CH_3CHO) was detected in many other numerous objects. If its deuterated species (CD_3CHO and CH_3CDO) have been previously studied in the millimeterwave range, the data concerning the 13C species are limited to few lines measured in 1957 up to 40 GHz. In this context we decided to study the 13C species of acetaldehyde. Acetaldehyde molecule displays a large amplitude motion: the hindered rotation of the methyl group with respect to the rest of the molecule. The analysis is performed with the Rho Axis Method. Recent versions of the codes include high orders term in order to reproduce the observed frequencies for large quantum numbers values as J-values as high as 70a,b,. Measurements and analysis of the rotational spectra of 13C isotopic species are in progress in Lille with a solid-state submillimetre-wave spectrometer (50-950 GHz), the first results will be presented. This work is supported by the contract ANR-08-BLAN-0054 and by the Programme National de Physico-Chimie du Milieu Interstellaire (PCMI-CNRS). Carvajal, M.; Margulès, L.; Tercero, B.; et al.A&A 500, (2009) 1109 Margulès, L.; Huet, T. R.; Demaison J.; et al.,ApJ 714, (2010) 1120. Ikeda, M.; Ohishi, M.; Nummelin, A.; et al., ApJ, 560, (2001) 792 Kleiner, I.; Lopez, J.-C.; Blanco, S.; et al.J. Mol. Spectrosc. 197, (1999) 275 Elkeurti M.; Coudert, L. H.; Medvedev, I. R.; et al.J. Mol. Spectrosc. 263, (2010) 145 Kilb, R.W.; Lin, C.C.; and Wilson, E.B.J. Chem. Phys. 26, (1957) 1695 Kleiner, I. J. Mol. Spectrosc. 260, (2010) 1 Ilyushin, V.V.; Kryvda, A; and Alekseev, E;J. Mol. Spectrosc. 255, (2009) 32

  16. Hyperpolarized C-13 MRS Cardiac Metabolism Studies in Pigs

    DEFF Research Database (Denmark)

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

    2012-01-01

    Cardiac metabolism assessment with hyperpolarized 13C magnetic resonance spectroscopy in pig models requires the design of dedicated coils capable of providing large field of view with high signal-to-noise ratio (SNR) data. This work presents a comparison between a commercial 13C quadrature...

  17. θ13PMNS=θC/√(2) from GUTs

    International Nuclear Information System (INIS)

    Antusch, Stefan; Gross, Christian; Maurer, Vinzenz; Sluka, Constantin

    2013-01-01

    The recent observations of the leptonic mixing angle θ 13 PMNS are consistent with θ 13 PMNS =θ C /√(2) (with θ C being the Cabibbo angle θ 12 CKM ). We discuss how this relation can emerge in Grand Unified Theories (GUTs) via charged lepton corrections. The key ingredient is that in GUTs the down-type quark Yukawa matrix and the charged lepton Yukawa matrix are generated from the same set of GUT operators, which implies that the resulting entries are linked and differ only by group-theoretical Clebsch factors. This allows a link θ 12 e ≈θ C to be established, which can induce θ 13 PMNS ≈θ C /√(2) provided that the 1–3 mixing in the neutrino mass matrix is much smaller than θ C . We find simple conditions under which θ 13 PMNS ≈θ C /√(2) can arise via this link in SU(5) GUTs and Pati–Salam models. We also discuss possible corrections to the exact relation. Using lepton mixing sum rules different neutrino mixing patterns can be distinguished by their predictions for the Dirac CP phase δ PMNS .

  18. A lower limit on the surface C-12/C-13 ratio in Alpha Orionis

    Science.gov (United States)

    Gautier, T. N., III; Fink, U.; Larson, H. P.; Thompson, R. I.

    1976-01-01

    The second overtone CO bands near 1.6 microns were analyzed in Alpha Ori using synthetic spectra. No firm identification of (C-13)O was made, which allowed a lower limit of 20 to be set on the C-12/C-13 ratio. A rather low microturbulent velocity of 2 km/s was found to match the spectrum of Alpha Ori best.

  19. Evaluation of [14C] and [13C]Sucrose as Blood-Brain Barrier Permeability Markers.

    Science.gov (United States)

    Miah, Mohammad K; Chowdhury, Ekram A; Bickel, Ulrich; Mehvar, Reza

    2017-06-01

    Nonspecific quantitation of [ 14 C]sucrose in blood and brain has been routinely used as a quantitative measure of the in vivo blood-brain barrier (BBB) integrity. However, the reported apparent brain uptake clearance (K in ) of the marker varies widely (∼100-fold). We investigated the accuracy of the use of the marker in comparison with a stable isotope of sucrose ([ 13 C]sucrose) measured by a specific liquid chromatography-tandem mass spectrometry method. Rats received single doses of each marker, and the K in values were determined. Surprisingly, the K in value of [ 13 C]sucrose was 6- to 7-fold lower than that of [ 14 C]sucrose. Chromatographic fractionation after in vivo administration of [ 14 C]sucrose indicated that the majority of the brain content of radioactivity belonged to compounds other than the intact [ 14 C]sucrose. However, mechanistic studies failed to reveal any substantial metabolism of the marker. The octanol:water partition coefficient of [ 14 C]sucrose was >2-fold higher than that of [ 13 C]sucrose, indicating the presence of lipid-soluble impurities in the [ 14 C]sucrose solution. Our data indicate that [ 14 C]sucrose overestimates the true BBB permeability to sucrose. We suggest that specific quantitation of the stable isotope ( 13 C) of sucrose is a more accurate alternative to the current widespread use of the radioactive sucrose as a BBB marker. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  20. Electron-nuclear magnetic resonance in the inverted state

    International Nuclear Information System (INIS)

    Ignatchenko, V.A.; Tsifrinovich, V.I.

    1975-01-01

    The paper considers the susceptibility of the electron-nucleus system of a ferromagnet when nuclear magnetization is inverted with respect to the hyperfine field direction. The inverted state is a situation in which nuclear magnetization is turned through π relative to its equilibrium orientation, whereas electron magnetization is in an equilibrium state with respect to an external magnetic field. The consideration is carried out for a thin plate magnetized in its plane. Amplification of a weak radiofrequency signal can be attained under the fulfilment of an additional inequality relating the interaction frequency with electron and nuclear relaxation parameters. The gain may exceed the gain for an inverted nuclear system in magnetically disordered substances. In the range of strong interaction between the frequencies of ferromagnetic (FMR) and nuclear magnetic (NMR) resonances the electron-nuclear magnetic resonance (ENMR) spectrum possesses a fine structure which is inverse to that obtained for the ENMR spectrum in a normal state. The inverted state ENMR line shape is analysed in detail for the case of so weak HF fields that the relaxation conditions may be regarded as stationary. The initial (linear) stages of a forced transient process arising in an electron-nuclear system under the effect of a strong HF field are briefly analysed

  1. Polysaccharides of algae. Pt. 37. Characterization of hybrid structure of substituted agarose from Polysiphonia morrowii (Rhodophyta, Rhodomelaceae) using. beta. -agarase and /sup 13/C-NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Usov, A.I.; Ivanova, E.G.

    1987-09-01

    Structure of gel-forming galactan from Polysiphonia morrowii was analysed using bacterial ..beta..-agarase and /sup 13/C-nuclear magnetic resonance (/sup 13/C-NMR) spectroscopy. The polysaccharide was shown to contain: a) blocks composed of agarobiose residues, partly 6-O-methylated and 6-sulfated, which are sensitive to enzymolysis; b) extended blocks composed of agarobiose 6-sulfate residues, which are resistant to ..beta..-agarase action. The latter blocks contain also ..beta..-D-galactopyranosyl-(1->4)-..cap alpha..-L-galactopyranose 6.6'-disulfate residues (biogenetic precursors of agarobiose 6-sulfate), which are hardly detectable by /sup 13/C-NMR spectrum of the starting polysaccharide. Action of alkali on the enzyme-resistant fraction afforded a polysaccharide preparation having /sup 13/C-NMR spectrum of agarose 6-sulfate.

  2. Catalytic dehydration of ethanol for poly 13 C compounds synthesis

    International Nuclear Information System (INIS)

    Almasan, Valer; Marginean, Petru; Lazar, Mihaela; Tusa, Florina

    2003-01-01

    Classical methods for the synthesis of organic compounds are not very well applied in the case of 13 C labeled compounds. One of the principal demands is to find the best method to transform a small quantity of isotopic reagent with a very high yield. In this case to obtain 13 C 2 chloroethanol from 13 C 2 ethanol there are two synthesis steps: - catalytic dehydration of ethanol to ethylene; - ethylene double bounding saturation: either via ethylene oxide (30% yield) or in diluted solution of chlorine. For the first step of synthesis we choose the thermal dehydration over alumina catalyst at 400 deg C. There were tested 2 samples of g alumina with 255 m 2 /g and 355 m 2 /g with very good results. In the second step of the synthesis we used the chlorine addition to ethylene in very diluted water solution. We have built a reactor which combined the two steps of this synthesis method to produce 13 C 2 chloroethanol from 13 C 2 ethanol. The global yield of method was 42%. (authors)

  3. Simultaneous measurement of neuronal and glial metabolism in rat brain in vivo using co-infusion of [1,6- 13C 2]glucose and [1,2- 13C 2]acetate

    Science.gov (United States)

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

    2009-02-01

    In this work the feasibility of measuring neuronal-glial metabolism in rat brain in vivo using co-infusion of [1,6- 13C 2]glucose and [1,2- 13C 2]acetate was investigated. Time courses of 13C spectra were measured in vivo while infusing both 13C-labeled substrates simultaneously. Individual 13C isotopomers (singlets and multiplets observed in 13C spectra) were quantified automatically using LCModel. The distinct 13C spectral pattern observed in glutamate and glutamine directly reflected the fact that glucose was metabolized primarily in the neuronal compartment and acetate in the glial compartment. Time courses of concentration of singly and multiply-labeled isotopomers of glutamate and glutamine were obtained with a temporal resolution of 11 min. Although dynamic metabolic modeling of these 13C isotopomer data will require further work and is not reported here, we expect that these new data will allow more precise determination of metabolic rates as is currently possible when using either glucose or acetate as the sole 13C-labeled substrate.

  4. Non-proliferation of nuclear weapons and nuclear security. Overview of safeguards requirements for States with limited nuclear material and activities

    International Nuclear Information System (INIS)

    Lodding, J.; Ribeiro, B.

    2006-06-01

    This booklet provides an overview of safeguards obligations that apply to States which are parties to the Nuclear Non-Proliferation Treaty (NPT) that have no nuclear facilities and only limited quantities of nuclear material. Most State parties to the NPT have no nuclear facilities and only limited quantities of nuclear material. For such States, safeguards implementation is expected to be simple and straightforward. This booklet provides an overview of the safeguards obligations that apply to such States. It is hoped that a better understanding of these requirements will facilitate the conclusion and implementation of safeguards agreements and additional protocols, and thereby contribute to the strengthening of the IAEA?s safeguards system and of collective security

  5. Non-proliferation of nuclear weapons and nuclear security. Overview of Safeguards requirements for States with limited nuclear material and activities

    International Nuclear Information System (INIS)

    Lodding, J.; Ribeiro, B.

    2006-06-01

    This booklet provides an overview of safeguards obligations that apply to States which are parties to the Nuclear Non-Proliferation Treaty (NPT) that have no nuclear facilities and only limited quantities of nuclear material. Most State parties to the NPT have no nuclear facilities and only limited quantities of nuclear material. For such States, safeguards implementation is expected to be simple and straightforward. This booklet provides an overview of the safeguards obligations that apply to such States. It is hoped that a better understanding of these requirements will facilitate the conclusion and implementation of safeguards agreements and additional protocols, and thereby contribute to the strengthening of the IAEA?s safeguards system and of collective security

  6. 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...

  7. Optically induced dynamic nuclear spin polarisation in diamond

    International Nuclear Information System (INIS)

    Scheuer, Jochen; Naydenov, Boris; Jelezko, Fedor; Schwartz, Ilai; Chen, Qiong; Plenio, Martin B; Schulze-Sünninghausen, David; Luy, Burkhard; Carl, Patrick; Höfer, Peter; Retzker, Alexander; Sumiya, Hitoshi; Isoya, Junichi

    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 13 C 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 13 C 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 13 C nuclear spins. Importantly for future applications we also realise polarisation protocols that are robust against an unknown misalignment between magnetic field and crystal axis. (paper)

  8. Avaliação do Metabolismo Nutricional em Poedeiras pela Técnica dos Isótopos Estáveis do Ccarbono (13C/12C Nutritional Metabolism Evaluation of Laying Hens Using Stable-Carbon Isotopes (13C/12C

    Directory of Open Access Journals (Sweden)

    AS Carrijo

    2000-09-01

    Full Text Available Os isótopos estáveis do carbono que eram utilizados em estudos ecológicos e paleoecológicos apresentaram um incremento nos últimos trinta anos, na utilização em estudos dietéticos em animais. Entretanto, existem poucas informações sobre o padrão metabólico e sobre as taxas de turnover do 13C em aves. O presente experimento estabeleceu curvas de substituição e taxas de movimentação do 13C no ovo e no fígado de aves de postura adultas, pela substituição da ração comercial por dietas compostas de grãos dos ciclos fotossintéticos C3 e C4, durante 50 dias. A diferença no conteúdo isotópico do delta per mil do carbono-13 (delta‰ 13C entre as duas dietas foi de 16,13‰. A taxa de substituição do 13C das dietas, nos tecidos, adequou-se num modelo exponencial, descrevendo o turnover do carbono nos tecidos analisados. As taxas de movimentação do 13C, nas aves alimentadas com dieta baseada em grãos C3, foi maior no fígado em relação ao ovo, com valores para a meia-vida de 2,9 e 3,7 dias, respectivamente. As aves que receberam ração com grãos C4 apresentaram uma taxa de turnover no ovo superior àquela obtida para o fígado, com meia-vida de 4,0 e 5,3 dias, respectivamente. Os valores do delta‰13C observados para ovo e fígado diferiram em aproximadamente 2‰ daqueles referentes às dietas.The stable carbon isotopes used in ecology and paleoecology during the last 30 years has now been used in dietary studies of animals. However, there are not enough studies on the metabolism patterns and turnover rates of the 13C in avian. This experiment established the turnover rates of the 13C in egg and liver tissues of adult laying hens through the substitution of commercial diets by diets containing C3 and C4 photosynthetic cycle grains for 50 days. The delta‰13C difference in two diets contents was 16.13‰. The diets 13C turnover rates in tissues were adapted in an exponential model that describes the isotopic carbon

  9. 14C and 13C in the atmosphere and soil air at two localities of Slovakia

    International Nuclear Information System (INIS)

    Sivo, A.; Simon, J.; Richtarikova, M.; Holy, K.; Polaskova, A.; Bulko, M.; Hola, O.

    2006-01-01

    In this paper there are presented the long-term measurements of 13 R and 14 R in urban and countryside atmosphere. The different conditions and particularities of both the localities which influence on the mentioned characteristics are pointed out. The existence of δ 13 C and δ 14 C variations and their phase correlation were confirmed as well as their origin were qualitatively explained. By means of the non-linear regression and harmonic analysis the trends of δ 13 C and δ 14 C variations was found. The study of δ 13 C and δ 14 C courses has shown that it can be used as an effective tool to determine the level of the anthropogenic CO 2 pollution of the atmosphere. (authors)

  10. Evidence for environmental conditions during the last 20 000 years in Southern Africa from C-13 in fossil hyrax dung

    CSIR Research Space (South Africa)

    Scott, L

    2000-11-01

    Full Text Available .elsevier.comrlocatergloplacha Evidence for environmental conditions during the last 20 000 years in Southern Africa from 13C in fossil hyrax dung L. Scott a,), J.C. Vogel b a Department of Botany and Genetics, Uni?ersity of the Orange Free State, PO Box 339, Bloemfontein 9300, South... in the studied hyrax middens, provide evidence that changes oc- curred on a regional scale. This is partly supported 13 by the d C sequences in stalagmite Talma and .Vogel, 1992 . In areas with summer-rains where AsweetB grass is likely to develop, d13C values...

  11. 23 CFR 1.3 - Federal-State cooperation; authority of State highway departments.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Federal-State cooperation; authority of State highway... MANAGEMENT AND ADMINISTRATION GENERAL § 1.3 Federal-State cooperation; authority of State highway departments... State in all matters relating to, and to enter into, on behalf of the State, all contracts and...

  12. 13C-NMR chemical shift databases as a quick tool to evaluate structural models of humic substances

    DEFF Research Database (Denmark)

    Nyrop Albers, Christian; Hansen, Poul Erik

    2010-01-01

    Models for humic and fulvic acids are discussed based on 13C liquid state NMR spectra combined with results from elemental analysis and titration studies. The analysis of NMR spectra is based on a full reconstruction of the NMR spectrum done with help of 13C-NMR data bases by adding up chemical...... side missing structural elements in the models can be suggested. A number of proposed structures for humic and fulvic acids are discussed based on the above analysis....

  13. Autoantibodies from primary biliary cirrhosis patients with anti-p95c antibodies bind to recombinant p97/VCP and inhibit in vitro nuclear envelope assembly

    Science.gov (United States)

    MIYACHI, K; HIRANO, Y; HORIGOME, T; MIMORI, T; MIYAKAWA, H; ONOZUKA, Y; SHIBATA, M; HIRAKATA, M; SUWA, A; HOSAKA, H; MATSUSHIMA, S; KOMATSU, T; MATSUSHIMA, H; HANKINS, R W; FRITZLER, M J

    2004-01-01

    We have reported previously that p95c, a novel 95-kDa cytosolic protein, was the target of autoantibodies in sera of patients with autoimmune hepatic diseases. We studied 30 sera that were shown previously to immunoprecipitate a 95 kDa protein from [35S]-methionine-labelled HeLa lysates and had a specific precipitin band in immunodiffusion. Thirteen sera were available to test the ability of p95c antibodies to inhibit nuclear envelope assembly in an in vitro assay in which confocal fluorescence microscopy was also used to identify the stages at which nuclear assembly was inhibited. The percentage inhibition of nuclear envelope assembly of the 13 sera ranged from 7% to 99% and nuclear envelope assembly and the swelling of nucleus was inhibited at several stages. The percentage inhibition of nuclear assembly was correlated with the titre of anti-p95c as determined by immunodiffusion. To confirm the identity of this autoantigen, we used a full-length cDNA of the p97/valosin-containing protein (VCP) to produce a radiolabelled recombinant protein that was then used in an immunoprecipitation (IP) assay. Our study demonstrated that 12 of the 13 (93%) human sera with antibodies to p95c immunoprecipitated recombinant p97/VCP. Because p95c and p97 have similar molecular masses and cell localization, and because the majority of sera bind recombinant p97/VCP and anti-p95c antibodies inhibit nuclear assembly, this is compelling evidence that p95c and p97/VCP are identical. PMID:15147362

  14. Volumetric spiral chemical shift imaging of hyperpolarized [2-(13) c]pyruvate in a rat c6 glioma model.

    Science.gov (United States)

    Park, Jae Mo; Josan, Sonal; Jang, Taichang; Merchant, Milton; Watkins, Ron; Hurd, Ralph E; Recht, Lawrence D; Mayer, Dirk; Spielman, Daniel M

    2016-03-01

    MRS of hyperpolarized [2-(13)C]pyruvate can be used to assess multiple metabolic pathways within mitochondria as the (13)C label is not lost with the conversion of pyruvate to acetyl-CoA. This study presents the first MR spectroscopic imaging of hyperpolarized [2-(13)C]pyruvate in glioma-bearing brain. Spiral chemical shift imaging with spectrally undersampling scheme (1042 Hz) and a hard-pulse excitation was exploited to simultaneously image [2-(13)C]pyruvate, [2-(13)C]lactate, and [5-(13)C]glutamate, the metabolites known to be produced in brain after an injection of hyperpolarized [2-(13)C]pyruvate, without chemical shift displacement artifacts. A separate undersampling scheme (890 Hz) was also used to image [1-(13)C]acetyl-carnitine. Healthy and C6 glioma-implanted rat brains were imaged at baseline and after dichloroacetate administration, a drug that modulates pyruvate dehydrogenase kinase activity. The baseline metabolite maps showed higher lactate and lower glutamate in tumor as compared to normal-appearing brain. Dichloroacetate led to an increase in glutamate in both tumor and normal-appearing brain. Dichloroacetate-induced %-decrease of lactate/glutamate was comparable to the lactate/bicarbonate decrease from hyperpolarized [1-(13)C]pyruvate studies. Acetyl-carnitine was observed in the muscle/fat tissue surrounding the brain. Robust volumetric imaging with hyperpolarized [2-(13)C]pyruvate and downstream products was performed in glioma-bearing rat brains, demonstrating changes in mitochondrial metabolism with dichloroacetate. © 2015 Wiley Periodicals, Inc.

  15. The analysis of B, C, N, and O by nuclear reactions

    International Nuclear Information System (INIS)

    Debras, G.; Deconninck, G.

    1979-01-01

    Nuclear reactions induced on light elements by lower energy deuterons are investigated. Differential cross section for 10 B(d,α 0 ) 8 Be, 10 B(d,α 1 ) 8 Be, 12 C(d,p 0 ) 13 C, 14 N(d,α 1 ) 12 C, 16 O(d,p 0 ) 17 O, 16 O(d,p 1 ) 17 O and 16 O(d,α 0 ) 14 N reactions are measured between 0.5 and 3 MeV at an observation angle of 135 0 with respect to the incident beam. Possible application of these reactions to the measurement of surface concentration is considered. Special emphasis was given on nitrogen determination in order to study nitrogen concentration in industrial glasses. Surface nitrogen repartition on glass, origin of nitrogen, influence of oxidizing and reducing conditions and glass structure are discussed. (author)

  16. In vivo 13C MRS in the mouse brain at 14.1 Tesla and metabolic flux quantification under infusion of [1,6-13C2]glucose.

    Science.gov (United States)

    Lai, Marta; Lanz, Bernard; Poitry-Yamate, Carole; Romero, Jackeline F; Berset, Corina M; Cudalbu, Cristina; Gruetter, Rolf

    2017-01-01

    In vivo 13 C magnetic resonance spectroscopy (MRS) enables the investigation of cerebral metabolic compartmentation while, e.g. infusing 13 C-labeled glucose. Metabolic flux analysis of 13 C turnover previously yielded quantitative information of glutamate and glutamine metabolism in humans and rats, while the application to in vivo mouse brain remains exceedingly challenging. In the present study, 13 C direct detection at 14.1 T provided highly resolved in vivo spectra of the mouse brain while infusing [1,6- 13 C 2 ]glucose for up to 5 h. 13 C incorporation to glutamate and glutamine C4, C3, and C2 and aspartate C3 were detected dynamically and fitted to a two-compartment model: flux estimation of neuron-glial metabolism included tricarboxylic acid cycle (TCA) flux in astrocytes (V g  = 0.16 ± 0.03 µmol/g/min) and neurons (V TCA n  = 0.56 ± 0.03 µmol/g/min), pyruvate carboxylase activity (V PC  = 0.041 ± 0.003 µmol/g/min) and neurotransmission rate (V NT  = 0.084 ± 0.008 µmol/g/min), resulting in a cerebral metabolic rate of glucose (CMR glc ) of 0.38 ± 0.02 µmol/g/min, in excellent agreement with that determined with concomitant 18 F-fluorodeoxyglucose positron emission tomography ( 18 FDG PET).We conclude that modeling of neuron-glial metabolism in vivo is accessible in the mouse brain from 13 C direct detection with an unprecedented spatial resolution under [1,6- 13 C 2 ]glucose infusion.

  17. Quantification of the "global" authigenic carbonate δ13C value and implications for carbon cycling

    Science.gov (United States)

    Loyd, S. J.

    2017-12-01

    Relationships among early Earth ocean chemistry, atmospheric chemistry and the evolution/radiation of life have been inferred from carbon isotope compositions (δ13C) of marine carbonates. Under steady-state conditions, the isotope compositions of marine carbonates reflect both the amount and δ13C of carbon entering and leaving the oceans. Recently the traditional "two-output" (marine carbonate and organic matter) mass-balance equation has been modified to include a third, authigenic carbonate output term. However, the formation mechanisms of authigenic carbonates remain poorly understood, particularly from a global prospective. The utility of the new mass-balance approach will be limited until authigenic carbonates are better characterized (e.g., through δ13C analyses). Authigenic carbonates form largely as a result of 1) the respiratory degradation of organic matter (e.g., sulfate reduction), 2) the oxidation of methane and 3) the production of methane. These major reaction pathways can produce authigenic carbonates with highly variable δ13C compositions (δ13Cac). Spatiotemporal variation in the extent and prevalence of different pathways therefore exert a first order control on "global" δ13Cac. Here, values are compiled from new and existing data sets and a modern, global δ13Cac is calculated. When calculated as an average of all data or an averaged mean of individual sites, this value is very similar to normal marine sedimentary organic matter. This finding suggests that marine sediments behave largely as closed systems in the context of organic matter degradation and carbonate authigenesis. In addition, the lack of significant difference between authigenic and organic δ13C implies that these two mass-balance output terms can be considered collectively in more recent time intervals. It may be appropriate to separate these two terms when characterizing more ancient settings when redox characteristics promoted more reducing organic matter degradation

  18. Solid state nuclear track detection principles, methods and applications

    CERN Document Server

    Durrani, S A; ter Haar, D

    1987-01-01

    Solid State Nuclear Track Detection: Principles, Methods and Applications is the second book written by the authors after Nuclear Tracks in Solids: Principles and Applications. The book is meant as an introduction to the subject solid state of nuclear track detection. The text covers the interactions of charged particles with matter; the nature of the charged-particle track; the methodology and geometry of track etching; thermal fading of latent damage trails on tracks; the use of dielectric track recorders in particle identification; radiation dossimetry; and solid state nuclear track detecti

  19. State and perspectives of Czechoslovakian nuclear law

    International Nuclear Information System (INIS)

    Bezdek, R.

    1992-01-01

    In Czechoslovakia, the peaceful utilization of nuclear energy is governed by a series of legislative norms of varied character and legal power. The most important are the Act No. 194/1988 and the Act No. 28/1984. The former defines the competence of the Czechoslovak Atomic Energy Commission (CAEC), which is the central authority of state administration in the field of utilization of nuclear energy. The latter deals with the State inspection for the nuclear safety of nuclear facilities. In accordance with this Act, the CAEC is the competent authority for the licensing and inspection of nuclear safety. In addition to the two main Acts, a series of CAEC Regulations govern nuclear activities (accounting and control of nuclear materials, radioactive waste management, physical protection, qualifications of personnel in nuclear facilities, quality assurance, etc.). There is no specific legislation governing nuclear third liability. The solution for the various shortcomings of the contemporary codification lies primarily in change of the present codification. This change, however, should not mean a general and indiscriminate ''destruction'' of the legal norms in force at present, but in gradual and purposive creation of an integral, legal system capable of reacting flexibly, the core of which would consist of an Act concerning the peaceful utilization of nuclear energy and on liability for nuclear damage. (author)

  20. 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.

    Science.gov (United States)

    Brekke, Eva M F; Walls, Anne B; Schousboe, Arne; Waagepetersen, Helle S; Sonnewald, Ursula

    2012-09-01

    The brain is highly susceptible to oxidative injury, and the pentose phosphate pathway (PPP) has been shown to be affected by pathological conditions, such as Alzheimer's disease and traumatic brain injury. While this pathway has been investigated in the intact brain and in astrocytes, little 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 of (13)C-labeled glucose via the PPP does not appear to contribute to the production of releasable lactate, it contributes to labeling of tricarboxylic acid (TCA) cycle intermediates and related amino acids. Based on glutamate isotopomers, it was calculated that PPP activity accounts for ~6% of glucose metabolism in cortical neurons and ~4% in cerebellar neurons. This is the first demonstration that pyruvate generated from glucose via the PPP contributes to the synthesis of acetyl CoA for oxidation in the TCA cycle. Moreover, the fact that (13)C labeling from glucose is incorporated into glutamate proves that both the oxidative and the nonoxidative stages of the PPP are active in neurons.

  1. 3D Hyperpolarized C-13 EPI with Calibrationless Parallel Imaging

    DEFF Research Database (Denmark)

    Gordon, Jeremy W.; Hansen, Rie Beck; Shin, Peter J.

    2018-01-01

    With the translation of metabolic MRI with hyperpolarized 13C agents into the clinic, imaging approaches will require large volumetric FOVs to support clinical applications. Parallel imaging techniques will be crucial to increasing volumetric scan coverage while minimizing RF requirements and tem...... strategies to accelerate and undersample hyperpolarized 13C data using 3D blipped EPI acquisitions and multichannel receive coils, and demonstrated its application in a human study of [1-13C]pyruvate metabolism....

  2. (13)C MR spectroscopy study of lactate as substrate for rat brain.

    Science.gov (United States)

    Qu, H; Håberg, A; Haraldseth, O; Unsgård, G; Sonnewald, U

    2000-01-01

    In order to address the question whether lactate in blood can serve as a precursor for cerebral metabolites, fully awake rats were injected intravenously with [U-(13)C]lactate or [U-(13)C]glucose followed 15 min later by decapitation. Incorporation of label from [U-(13)C]glucose was seen mainly in glutamate, GABA, glutamine, aspartate, alanine and lactate. More label was found in glutamate than glutamine, underscoring the predominantly neuronal metabolism of pyruvate from [U-(13)C]glucose. It was estimated that the neuronal metabolism of acetyl CoA from glucose accounts for at least 66% and the glial for no more than 34% of the total glucose consumption. When [U-(13)C]lactate was the precursor, label incorporation was similar to that observed from [U-(13)C]glucose, but much reduced. Plasma analysis revealed the presence of approximately equal amounts of [1,2,3-(13)C]- and [1,2-(13)C]glucose, showing gluconeogenesis from [U-(13)C]lactate. It was thus possible that the labeling seen in the cerebral amino acids originated from labeled glucose, not [U-(13)C]lactate. However, the presence of significantly more label in [U-(13)C]- than in [2,3-(13)C]alanine demonstrated that [U-(13)C]lactate did indeed cross the blood-brain barrier, and was metabolized further in the brain. Furthermore, contributions from pyruvate carboxylase (glial enzyme) were detectable in glutamine, glutamate and GABA, and were comparatively more pronounced in the glucose group. This indicated that relatively more pyruvate from lactate than glucose was metabolized in neurons. Surprisingly, the same amount of lactate was synthesized via the tricarboxylic acid cycle in both groups, indicating transfer of neurotransmitters from the neuronal to the astrocytic compartment, as previous studies have shown that this lactate is synthesized primarily in astrocytes. Taking into consideration that astrocytes take up glutamate more avidly than GABA, it is conceivable that neuronal lactate metabolism was more

  3. Spectrally edited 2D 13Csbnd 13C NMR spectra without diagonal ridge for characterizing 13C-enriched low-temperature carbon materials

    Science.gov (United States)

    Johnson, Robert L.; Anderson, Jason M.; Shanks, Brent H.; Fang, Xiaowen; Hong, Mei; Schmidt-Rohr, Klaus

    2013-09-01

    Two robust combinations of spectral editing techniques with 2D 13Csbnd 13C NMR have been developed for characterizing the aromatic components of 13C-enriched low-temperature carbon materials. One method (exchange with protonated and nonprotonated spectral editing, EXPANSE) selects cross peaks of protonated and nearby nonprotonated carbons, while the other technique, dipolar-dephased double-quantum/single-quantum (DQ/SQ) NMR, selects signals of bonded nonprotonated carbons. Both spectra are free of a diagonal ridge, which has many advantages: Cross peaks on the diagonal or of small intensity can be detected, and residual spinning sidebands or truncation artifacts associated with the diagonal ridge are avoided. In the DQ/SQ experiment, dipolar dephasing of the double-quantum coherence removes protonated-carbon signals; this approach also eliminates the need for high-power proton decoupling. The initial magnetization is generated with minimal fluctuation by combining direct polarization, cross polarization, and equilibration by 13C spin diffusion. The dipolar dephased DQ/SQ spectrum shows signals from all linkages between aromatic rings, including a distinctive peak from polycondensed aromatics. In EXPANSE NMR, signals of protonated carbons are selected in the first spectral dimension by short cross polarization combined with dipolar dephasing difference. This removes ambiguities of peak assignment to overlapping signals of nonprotonated and protonated aromatic carbons, e.g. near 125 ppm. Spin diffusion is enhanced by dipolar-assisted rotational resonance. Before detection, Csbnd H dipolar dephasing by gated decoupling is applied, which selects signals of nonprotonated carbons. Thus, only cross peaks due to magnetization originating from protonated C and ending on nearby nonprotonated C are retained. Combined with the chemical shifts deduced from the cross-peak position, this double spectral editing defines the bonding environment of aromatic, COO, and Cdbnd O carbons

  4. Development and performance of a 129-GHz dynamic nuclear polarizer in an ultra-wide bore superconducting magnet.

    Science.gov (United States)

    Lumata, Lloyd L; Martin, Richard; Jindal, Ashish K; Kovacs, Zoltan; Conradi, Mark S; Merritt, Matthew E

    2015-04-01

    We sought to build a dynamic nuclear polarization system for operation at 4.6 T (129 GHz) and evaluate its efficiency in terms of (13)C polarization levels using free radicals that span a range of ESR linewidths. A liquid helium cryostat was placed in a 4.6 T superconducting magnet with a 150-mm warm bore diameter. A 129-GHz microwave source was used to irradiate (13)C enriched samples. Temperatures close to 1 K were achieved using a vacuum pump with a 453-m(3)/h roots blower. A hyperpolarized (13)C nuclear magnetic resonance (NMR) signal was detected using a saddle coil and a Varian VNMRS console operating at 49.208 MHz. Samples doped with free radicals BDPA (1,3-bisdiphenylene-2-phenylallyl), trityl OX063 (tris{8-carboxyl-2,2,6,6-benzo(1,2-d:4,5-d)-bis(1,3)dithiole-4-yl}methyl sodium salt), galvinoxyl ((2,6-di-tert-butyl-α-(3,5-di-tert-butyl-4-oxo-2,5-cyclohexadien-1-ylidene)-p-tolyloxy), 2,2-diphenylpicrylhydrazyl (DPPH) and 4-oxo-TEMPO (4-Oxo-2,2,6,6-tetramethyl-1-piperidinyloxy) were assayed. Microwave dynamic nuclear polarization (DNP) spectra and solid-state (13)C polarization levels for these samples were determined. (13)C polarization levels close to 50 % were achieved for [1-(13)C]pyruvic acid at 1.15 K using the narrow electron spin resonance (ESR) linewidth free radicals trityl OX063 and BDPA, while 10-20 % (13)C polarizations were achieved using galvinoxyl, DPPH and 4-oxo-TEMPO. At this field strength free radicals with smaller ESR linewidths are still superior for DNP of (13)C as opposed to those with linewidths that exceed that of the (1)H Larmor frequency.

  5. 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.

  6. Pion production and the nuclear equation of state

    International Nuclear Information System (INIS)

    Harris, J.W.; Odyniec, G.; Pugh, H.G.

    1984-10-01

    There has been considerable recent interest in the nuclear equation of state and how it may be determined in relativistic nucleus-nucleus collisions. In these collisions extremely high temperatures are reached and compression to densities several times that of normal nuclear matter are predicted. This affords us the unique opportunity to study, in a somewhat controlled manner, the behavior of nuclear matter under these extreme conditions. If the observables that are measured in experiments can be related in a quantitative way to state variables of the system then the equation of state can be extracted. This relation plays a very important role in understanding the formation and collapse of supernovae and the stability and structure of neutron stars. Furthermore, it can be used to test and constrain field theoretical approaches to nuclear matter and to help to better understand the dynamics of high energy nucleus-nucleus collisions. In this presentation the relationship between the nuclear equation of state and relativistic nucleus-nucleus collisions will be discussed with an emphasis on how to extract the former. That a high density state of the collision should exist will be shown. One observable, namely the pion multiplicity, will be shown to survive the succeeding stages of the collision process to provide information on the equation of state at high densities. The resulting equation of state will be presented and discussed in the light of recent theoretical development. 34 refs., 12 figs

  7. C-12/C-13 Ratio in Ethane on Titan and Implications for Methane's Replenishment

    Science.gov (United States)

    Jennings, Donald E.; Romani, Paul N.; Bjoraker, Gordon L.; Sada, Pedro V.; Nixon, Conor A.; Lunsford, Allen W.; Boyle, Robert J.; Hesman, Brigette E.; McCabe, George H.

    2009-01-01

    The C-12/C-13 abundance ratio in ethane in the atmosphere of Titan has been measured at 822 cm(sup -1) from high spectral resolution ground-based observations. The value 89(8), coincides with the telluric standard and also agrees with the ratio seen in the outer planets. It is almost identical to the result for ethane on Titan found by the composite infrared spectrometer (CIRS) on Cassini. The C-12/C-13 ratio for ethane is higher than the ratio measured in atmospheric methane by Cassini/Huygens GCMS, 82.3(l), representing an enrichment of C-12 in the ethane that might be explained by a kinetic isotope effect of approximately 1.1 in the formation of methyl radicals. If methane is being continuously resupplied to balance photochemical destruction, then we expect the isotopic composition in the ethane product to equilibrate at close to the same C-12/C-13 ratio as that in the supply. The telluric value of the ratio in ethane then implies that the methane reservoir is primordial.

  8. Status of nuclear desalination in IAEA member states

    International Nuclear Information System (INIS)

    2007-01-01

    Some of the IAEA Member States have active nuclear desalination programmes and, during the last few years, substantial overall progress has been made in this field. As part of the ongoing activities within the IAEA's nuclear power programme, it was thus decided to prepare a status report, which would briefly describe the recent nuclear seawater desalination related developments and relevant IAEA activities. This status report briefly covers salient aspects of the new generation reactors and a few innovative reactors being considered for desalination and other non-electrical applications, the recent advances in the commonly employed desalination processes and their coupling to nuclear reactors. A summary of techno-economic feasibility studies carried out in interested Member States has been presented and the potable water cost reduction strategies from nuclear desalination plants have been discussed. The socio-economic and environmental benefits of nuclear power driven desalination plants have been elaborated. It is expected that the concise information provided in this report would be useful to the decision makers in the Member States and would incite them to consider or to accelerate the deployment of nuclear desalination projects in their respective countries

  9. Coherent fragmentation of 12C nuclei of momentum 4.5 GeV/ c per nucleon through the 8Beg.s.+4He channel in a nuclear photoemulsion containing lead nuclei

    Science.gov (United States)

    Belaga, V. V.; Gerasimov, S. G.; Dronov, V. A.; Peresadko, N. G.; Pisetskaya, A. V.; Rusakova, V. V.; Fetisov, V. N.; Kharlamov, S. P.; Shesterkina, L. N.

    2017-07-01

    A two-particle channel in which an unbound nucleus of 8Be in the ground state (8Beg.s.) was one of the fragments was selected among events where 12C nuclei of momentum 4.5 GeV/c per nucleon undergo coherent dissociation into three alpha particles. The events in question were detected in a track nuclear photoemulsion containing lead nuclei, which was irradiated at the synchrophasotron of the Laboratory of High Energies at the Joint Institute for Nuclear Research (JINR, Dubna). The average transverse momentum of alpha particles produced upon the decay of 8Beg.s. nuclei was 87±6 MeV/ c, while that for "single" alpha (αs) particles was 123±15 MeV/ c. The average value of the transverse-momentum transfer in the reaction being considered, Pt(12C), was 223 ± 20 MeV/ c. The average value of the cross section for this channel involving Ag and Br target nuclei was 13 ± 4 mb, while the cross section for the reaction on the Pb nucleus was 40 ± 15 mb. The Coulomb dissociation contribution evaluated on the basis of the number of events where the momentum P t(12C) did not exceed 0.1 GeV/c saturated about 20%. In nine events, the measured total transverse energy of the fragments in the reference frame comoving with the decaying carbon nucleus did not exceed 0.45 MeV, which did not contradict the excitation of the participant 12C nucleus to the level at 7.65 MeV. The average value of the transverse momentum in those events was 234 ± 25 MeV/ c.

  10. 13C metabolic flux analysis: optimal design of isotopic labeling experiments.

    Science.gov (United States)

    Antoniewicz, Maciek R

    2013-12-01

    Measuring fluxes by 13C metabolic flux analysis (13C-MFA) has become a key activity in chemical and pharmaceutical biotechnology. Optimal design of isotopic labeling experiments is of central importance to 13C-MFA as it determines the precision with which fluxes can be estimated. Traditional methods for selecting isotopic tracers and labeling measurements did not fully utilize the power of 13C-MFA. Recently, new approaches were developed for optimal design of isotopic labeling experiments based on parallel labeling experiments and algorithms for rational selection of tracers. In addition, advanced isotopic labeling measurements were developed based on tandem mass spectrometry. Combined, these approaches can dramatically improve the quality of 13C-MFA results with important applications in metabolic engineering and biotechnology. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Measurement of the natural variation of 13C/12C isotope ratio in organic samples

    International Nuclear Information System (INIS)

    Ducatti, C.

    1977-01-01

    The isotopic ratio analysis for 13 C/ 12 C by mass spectrometry using a 'Working standard' allows the study of 13 C natural variation in organic material, with a total analytical error of less than 0,2%. Equations were derived in order to determine 13 C/ 12 C and 18 O/ 16 O ratios related to the 'working standard' CENA-std and to the international standard PDB. Isotope ratio values obtained with samples prepared in two different combustion apparatus were compared; also the values obtained preparing samples by acid decomposition of carbonaceous materials were compared with the values obtained in different international laboratories. Utilizing the methodology proposed, several leaves collected at different heights of different vegetal species, found 'inside' and 'outside' of the Ducke Forest Reserve, located in the Amazon region, are analysed. It is found that the 13 C natural variation depends upon metabolic process and environmental factors, both being factors which may be qualified as parcial influences on the CO 2 cycle in the forest. (author) [pt

  12. Parent di-nuclear quasimolecular states as exotic resonant states

    International Nuclear Information System (INIS)

    Grama, N.

    2002-01-01

    It in shown that the parent di-nuclear quasimolecular state is an exotic resonant state that corresponds to a S-matrix pole in the neighbourhood of an attractor in the k-plane. The properties of the parent quasimolecular states i.e. energy, widths, deviation from the linear dependence of the energy on l(l + 1) doorway character and criteria for observability, result naturally from the general properties of the exotic resonant states. (author)

  13. 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.

  14. Results of activities of the State Office for Nuclear Safety in state supervision of nuclear safety of nuclear facilities and radiation protection in 2003

    International Nuclear Information System (INIS)

    Kovar, P.

    2004-01-01

    The report summarises results of activities of the State Office for Nuclear Safety (SUJB) in the supervision of nuclear safety and radiation protection in the Czech Republic. The first part of the report evaluates nuclear safety of nuclear installations and contains information concerning the results of supervision of radiation protection in 2003 in the Czech Republic. The second part of the report describes new responsibilities of the SUJB in the domain of nuclear, chemical, bacteriological (biological) and toxin weapons ban. (author)

  15. Fish Movement and Dietary History Derived from Otolith (delta)13C

    Energy Technology Data Exchange (ETDEWEB)

    Weber, P K; Finlay, J C; Power, M E; Phillis, C C; Ramon, C E; Eaton, G F; Ingram, B L

    2005-09-08

    Habitat use and food web linkages are critical data for fish conservation and habitat restoration efforts, particularly for threatened salmonids species. Otolith microchemistry has been shown to be a powerful tool for reconstructing fish movement, but over small distances (kilometers), geology-derived differences in otolith chemistry are rare. Here, we demonstrate that otolith {sup 13}C/{sup 12}C ratio (i.e. {delta}{sup 13}C) of anadromous steelhead trout can be used to distinguish residence in small streams from residence in larger streams and rivers. While previous research has shown that water dissolved inorganic carbon {delta}{sup 13}C is the primary source of carbon in otoliths, the downstream change in food {delta}{sup 13}C in this watershed appears to be the primary control on otolith {delta}{sup 13}C. As a result, this method can also be applied to the problem of reconstructing feeding history at a location.

  16. Determinação da razão isotópica δ13C em bebidas comerciais a base de laranja Determination of isotope ratio (δ13C in commercial orange beverages

    Directory of Open Access Journals (Sweden)

    Elvio Cardoso Queiroz

    2009-08-01

    relation to soluble solids. The insoluble solids (pulp were used as internal isotopic standard for the orange juice employed in commercial beverage. The isotope analysis of commercial beverages showed four adulterations: one sample of whole orange juice, one of concentrate juice, and two of sweetened orange juice. For samples with the absence of pulp, we adopted the isotopic value of δ13C -26.19‰ as standard C3 source, by compiling a database of 31 samples of pure orange juice from 12 producing regions of the state of São Paulo. In these beverages (energetic beverage, mixed beverage and "citric fruit", the isotopic value of 13C was similar to sugar cane (δ13C -12.48‰ showing few fruit juice in its formulation.

  17. 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

    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 both the transmit and receive performance of the radiofrequency (RF) coil. Maximizing coil efficiency will maximize also the signal......-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...

  18. Differential cross section measurement of radiative capture of protons by nuclei 12C

    International Nuclear Information System (INIS)

    Burtebayev, N.; Zazulin, D.M.; Buminskii, V.P.; Zarifov, R.A.; Tohtarov, R.N.; Sagindykov, Sh.Sh.; Baktibayev, M.K.

    2003-01-01

    Measurements of differential cross sections of nuclear reaction 12 C(p, γ) 13 N at 0, 45, 90, 135 Deg. to beam direction of flying protons in the field of E p = 350-1100 KeV with an error it is not worse than 10 % have been carried out. Most important was studied, from the astrophysical point of view, process of capture of protons by nucleuses 12 C on the ground state of a nucleus 13 N. It is experimentally shown isotropy of angular distribution of differential cross sections of reaction 12 C(p, γ) 13 N, in the given field energy of protons

  19. The synthesis of 13C-bilirubin and its use in the validation of bilirubin kinetic studies in rats

    International Nuclear Information System (INIS)

    Sturrock, E.D.

    1994-04-01

    The total synthesis of [10- 13 C] bilirubin IXα], the principal waste product of haem degradation, is described. Site specific labelling was accomplished by the Vilsmeier formulation of one of the dipyrrolic fragments using [1- 13 C] dimethylformamide. The penultimate dehydrohalogenation reaction was complicated by a competing elimination reaction which yielded a bridged biliverdin derivative. The base catalysed reaction affords a novel [10- 13 C]-8,12-bis(2-methoxycarbonylethyl)-7,13,17-trimethyl-2,18-propano-3-vinylbilin-1,19(21H,24H)-dione in which the 2 and 18 positions of the macrocycle are bridged with a propano tether, the structure has been established using single crystal X-ray and 1 H nuclear Overhauser effect studies. [ 14 C]bilirubin was prepared, bio synthetically, using [ 14 C]aminolevulinic acid. Bilirubin kinetics in 4 rats were measured by the analysis of the plasma disappearance of [ 14 C]bilirubin in a two-compartment model. The plasma half-life of the first and second exponentials were 1.97 and 32.8 minutes respectively. The data were used to determine model independent parameters k 12 , k 21 , and k 20 . In the proposed model, plasma unconjugated bilirubin exchanges with a hepatic unconjugated bilirubin pool. Bilirubin is eliminated from the system via the proposed hepatic pool. These studies provide an analysis of the kinetics of unconjugated bilirubin in rates and are intended to serve as a reference point for studies using a stable isotope of bilirubin. The plasma disappearance of [10- 13 C]bilirubin IXα in three rats was studied using mass spectrometry to measure the bilirubin δ 13 C. Validation of the experimental procedure in terms of range and reproducibility of the detection method was carried out. The half lives of the initial and terminal exponentials were 2.27±2.5 and 22.8±12.9 minutes. Despite the large 95% confidence limits calculated for these clearance curves they serve as an important foundation for future bilirubin kinetic

  20. Testing compound-specific δ13C of amino acids in mussels as a new approach to determine the average 13C values of primary production in littoral ecosystems

    Science.gov (United States)

    Vokhshoori, N. L.; Larsen, T.; McCarthy, M.

    2012-12-01

    Compound-specific isotope analysis of amino acids (CSI-AA) is a technique used to decouple trophic enrichment patterns from source changes at the base of the food web. With this new emerging tool, it is possible to precisely determine both trophic position and δ15N or δ13C source values in higher feeding organisms. While most work to date has focused on nitrogen (N) isotopic values, early work has suggested that δ13C CSI-AA has great potential as a new tracer both to a record δ13C values of primary production (unaltered by trophic transfers), and also to "fingerprint" specific carbon source organisms. Since essential amino acids (EAA) cannot be made de novo in metazoans but must be obtained from diet, the δ13C value of the primary producer is preserved through the food web. Therefore, the δ13C values of EAAs act as a unique signature of different primary producers and can be used to fingerprint the dominant carbon (C) source driving primary production at the base of the food web. In littoral ecosystems, such as the California Upwelling System (CUS), the likely dominant C sources of suspended particulate organic matter (POM) pool are kelp, upwelling phytoplankton or estuarine phytoplankton. While bulk isotopes of C and N are used extensively to resolve relative consumer hierarchy or shifting diet in a food web, we found that the δ13C bulk values in mussels cannot distinguish exact source in littoral ecosystems. Here we show 15 sites within the CUS, between Cape Blanco, OR and La Jolla, CA where mussels were sampled and analyzed for both bulk δ13C and CSI-AA. We found no latitudinal trends, but rather average bulk δ13C values for the entire coastal record were highly consistent (-15.7 ± 0.9‰). The bulk record would suggest either nutrient provisioning from kelp or upwelled phytoplankton, but 13C-AA fingerprinting confines these two sources to upwelling. This suggests that mussels are recording integrated coastal phytoplankton values, with the enriched

  1. State and nuclear power: conflict and control in the western world

    International Nuclear Information System (INIS)

    Camilleri, J.A.

    1984-01-01

    An analysis of the political, cultural, and international dimensions of the nuclear power conflict, this book focuses on the role of the advanced capitalist state in the establishment and subsequent development of the nuclear industry. The author examines the mode, extent, and efficacy of state intervention in nuclear decision making and the political contest which has emerged between pro- and anti-nuclear elements in society, which have confronted the state with a new challenge to its authority. Separate chapter headings are: (1) Origins of the Peaceful Atom, (2) The Emerging Nuclear State, (3) The State's Authority under Challenge, (4) The State and the Crisis of Legitimacy, (5) The Impact of Recession, (6) The Politics of the Fuel Cycle, (7) International Nuclear Politics, and (8) Nuclear Power and the Crisis of Capitalism. 47 references, 1 figure, 3 tables

  2. Irradiation effects on C/C composite materials for high temperature nuclear applications

    International Nuclear Information System (INIS)

    Eto, M.; Ugachi, H.; Baba, S.I.; Ishiyama, S.; Ishihara, M.; Hayashi, K.

    2000-01-01

    Excellent characteristics such as high strength and high thermal shock resistance of C/C composite materials have led us to try to apply them to the high temperature components in nuclear facilities. Such components include the armour tile of the first wall and divertor of fusion reactor and the elements of control rod for the use in HTGR. One of the most important aspects to be clarified about C/C composites for nuclear applications is the effect of neutron irradiation on their properties. At the Japan Atomic Energy Research Institute (JAERI), research on the irradiation effects on various properties of C/C composite materials has been carried out using fission reactors (JRR-3, JMTR), accelerators (TANDEM, TIARA) and the Fusion Neutronics Source (FNS). Additionally, strength tests of some neutron-irradiated elements for the control rod were carried out to investigate the feasibility of C/C composites. The paper summarises the R and D activities on the irradiation effects on C/C composites. (authors)

  3. Relationships between tobacco leaf δ"1"3C and physiological characteristics

    International Nuclear Information System (INIS)

    Wang Yi; Song Pengfei; Yan Kan; Tan Shuwen; Wu Xiaoxiao; Chen Zongyu

    2013-01-01

    In this paper, the flue-cured tobacco K326 was employed to study the abundance of carbon isotope composition, photosynthetic pigment content, soluble protein content and leaf mass per area (LMA) of tobacco leaf which were grown at four testing sites of different altitude (T_1, T_2, T_3, T_4). The correlations of carbon isotope composition with altitude, leaf position and physiological measures were understood as well. Results showed that δ"1"3C of those samples varied from -27.4‰ to -23.4‰. The δ"1"3C of samples from T_1, T_2and T_3 were increased with rising of the leaf position. δ"1"3C of middle and upper leaves from T_1, T_2and T_3 were positively correlated with altitude. However, δ"1"3C of samples from T_4 ranging from -26.8‰ to -26.4‰ was lower than the values from previous samples. The δ"1"3C also decreased with the increasing of leaf position, and was significantly negatively correlated with chlorophyll content and chlorophyll/carotinoid ratio (P < 0.05). The δ"1"3C was not significantly correlated with carotinoid content and chlorophyll a/b ratio. Meanwhile, it was positively correlated with soluble protein content and LMA significantly (P < 0.01). Generally, our findings indicated that chlorophyll content, chlorophyll/carotenoid ratio, soluble protein content, and LMA had strong relationships with δ"1"3C, whereas the relationship of δ"1"3C with altitude and leaf position was still unclear. (authors)

  4. Effect of substrate intake and physiological state on background 13CO2 enrichment

    International Nuclear Information System (INIS)

    Wolfe, R.R.; Shaw, J.H.F.; Nadel, E.R.; Wolfe, M.H.

    1984-01-01

    The natural enrichment of 13 C in energy substrates varies, and this variation must be taken into account when stable isotopic tracers are used in metabolic studies. This is conventionally accomplished by measuring background samples taken before the tracer infusion begins and subtracting these values from postinfusion values. Whereas this approach is satisfactory if no perturbation occurs between the collection of the background samples and the collection of postinfusion sample, the data presented in this paper show that any change in the metabolic state can significantly alter the background enrichment of expired CO 2 . This study not only confirmed that the introduction of natural energy sources may alter the background enrichment of CO 2 , but we also found that changes in substrate oxidation induced by different physiological states, such as exercise, can cause significant changes in expired CO 2 enrichments. Conclusions from studies in which oxidation of substrates were measured by means of a 13 C tracer but potential changes in background enrichments were not accounted for must, therefore, be reassessed

  5. Resolution Improvement in Multidimensional Nuclear Magnetic Resonance Spectroscopy of Proteins

    International Nuclear Information System (INIS)

    Duma, L.

    2004-01-01

    The work presented in this thesis is concerned with both liquid-state and solid-state nuclear magnetic resonance (NMR) spectroscopy. Most of this work is devoted to the investigation by solid-state NMR of C 13 -enriched compounds with the principal aim of presenting techniques devised for further improving the spectral resolution in multidimensional NMR of microcrystalline proteins. In fully C 13 -labelled compounds, the J-coupling induces a broadening of the carbon lineshapes. We show that spin-state-selective technique called IPAP can be successfully combined with standard polarisation transfer schemes in order to remove the J-broadening in multidimensional solid-state NMR correlation experiments of fully C 13 -enriched proteins. We present subsequently two techniques tailored for liquid-state NMR spectroscopy. The carbon directly detected techniques provide chemical shift information for all backbone hetero-nuclei. They are very attracting for the study of large bio-molecular systems or for the investigation of paramagnetic proteins. In the last part of this thesis, we study the spin-echo J-modulation for homonuclear two-spin 1/2 systems. Under magic-angle spinning, the theory of J-induced spin-echo modulation allows to derive a set of modulation regimes which give a spin-echo modulation exactly equal to the J-coupling. We show that the chemical-shift anisotropy and the dipolar interaction tend to stabilize the spin-echo J-modulation. The theoretical conclusions are supported by numerical simulations and experimental results obtained for three representative samples containing C 13 spin pairs. (author)

  6. Clinical value of 13C-UBT diagnosing infection of the Hp

    International Nuclear Information System (INIS)

    Xu Changde; Chen Shaoliang; Liu Wenguan

    2004-01-01

    100 dyspeptic patients are performed an endoscopy with biopsy for histology, rapid urease test, 13 C-urea breath test( 13 C-UBT) and ASSURE TM Hp rapid Test(HpRT). Patients are considered to be infected if both histology and biopsies yield positive results, and not infected when both tests are negative. The pathology and persons responsible for endoscopy, urease test and 13 C-UBT are unaware of the results from the other diagnostic methods. The 13 C-UBT has the following results: sensitivity 96% ,specificity 95%; rapid urease test has the following results: sensitivity 79%, specificity 76%; HpRT has the following results: sensitivity 86%, specificity 88%. 13 C-UBT provides excellent sensitivity and specificity for the diagnosis of Hp. Pylori infected Hp, it can be the first choice for detecting the infection of the Hp. (authors)

  7. Nuclear deterrence in second tier nuclear weapon states: a case study of India

    International Nuclear Information System (INIS)

    Sethi, Manpreet

    2009-12-01

    Nuclear deterrence today anchors the national security of all states that possess nuclear weapons. Certain principles or requirements of nuclear deterrence are the same for all such countries. For instance, the ability to threaten with unacceptable damage, or the ability to raise the costs of an action that an adversary might want to take by threatening punishment that would make the act seem meaningless and even regrettable. But must every nuclear nation indulge in an exercise of large-scale warhead accumulation or yield refinements through nuclear testing, or creation of elaborate nuclear war fighting plans in order to claim credible deterrence? Can the practice of deterrence in the second tier states follow a different course? The study examines the manner in which India is engaged in constructing a credible and stable deterrence relationship with two of its nuclear armed adversaries, Pakistan and China with an arsenal much smaller, and command and control structures far simpler than in any of the P-5 nations. Does this difference impact the nature of its nuclear deterrence? In its efforts at creating and sustaining credible nuclear deterrence should India necessarily be expected to follow the same path and rules as those of the P-5? Would it be compelled to build hundreds of warheads and a huge weapons infrastructure? Would a deterrence based on anything less not be credible or stable? The study concludes that even countries with small nuclear arsenals behave no differently from states that possess several thousands of such weapons. The assumption that small nuclear arsenals and rudimentary command and control lend themselves to temptations of easy nuclear use is misplaced. Credible nuclear deterrence between India and Pakistan or India and China would hold on the same bases it has held elsewhere - fear of nuclear destruction, imposition of unacceptable damage, and the ability to rationally calculate and weigh the benefits against the costs of use of nuclear

  8. Analyzing power measurements for the (π+,π0) reaction on a polarized 13C target

    International Nuclear Information System (INIS)

    Goergen, J.J.

    1991-05-01

    The analyzing powers A y differential cross sections dσ/dΩ for the reaction 13 C(π + ,π 0 ) 13 N have been measured for forward scattering angles at an incident pion kinetic energy of T pi + = 163 MeV by using a transversely polarized target. Analyzing powers and reaction cross sections impose stringent constrains on nuclear reaction models and can be used to test the present understanding of nuclear structure for 1p-shell nuclei. The resulting A y are compared to the predictions of first-order Distorted Wave Impulse Approximation (DWIA) calculations, which reproduce well the differential cross sections. Although there is qualitative agreement at forward angles, the quantitative agreement is poor, especially at scattering angles larger than 50 degrees. Since the DWIA calculations do not appear to be strongly sensitive to the assumed nuclear structure model, the discrepancy in describing the analyzing powers suggests that the reaction mechanism may not yet be well understood and higher order corrections may be important. Also measured were the analyzing powers for the elementary charge exchange reaction π - bar p → π degrees n over the same angular range and at an incident pion kinetic energy of T pi - = 161 MeV. The results are compared to the most recents phase shift predictions. Within the experimental uncertainties, phase shift calculations agree with the measured A y and no changes in the πN phase shifts near the P 33 resonance are needed to describe the data

  9. Effect of the nitrogen unshared electron pair on the direct /sup 13/C-/sup 13/C spin-spin coupling constant of a neighboring bond in oximes

    Energy Technology Data Exchange (ETDEWEB)

    Shcherbakov, V.V.; Krivdin, L.B.; Kalabin, G.A.; Trofimov, B.A.

    1986-11-20

    The authors have previously established that the direct /sup 13/C-/sup 13/C coupling constants are stereospecific relative to the orientation of unshared electron pairs (UEP) of nitrogen and oxygen atoms. Here they show that the nitrogen UEP produces a positive contribution to the direct /sup 13/C-/sup 13/C coupling constant of an adjacent syn-periplanar carbon-carbon bond and not to a negative contribution of the corresponding constant of the anti-periplanar bond. Thus, the observed effect is not a consequence of the interaction of the heteroatom UEP with the anti-bonding orbital of the adjacent anti-periplanar bond (n/sub o-o/* interaction) as in the case of anomeric and related effects.

  10. Contribution of the C.E.A. to standardization of nuclear plant equipments

    International Nuclear Information System (INIS)

    Dumax, P.; Seran, R.

    1980-01-01

    In research and production laboratories working in the nuclear field standardization of equipments greatly improves the profits of the installation and the protection of individuals and goods. The standardization effort on technical equipments of shielding, handling, detection and safety (so called P.M.D.S.) initiated by the C.E.A. in 1967 is being carried out now within the Institute of Protection and Nuclear Safety (I.P.S.N.) by a technical Service specialized in protection and dosimetry (S.T.E.P.D.). Its purpose is to establish standardization documents for internal use and to take part in the work of official standardization organizations. The benefits of standardization are reviewed. The achievements of the various working groups common to C.E.A. centers are stated and the documents published or to be published are listed [fr

  11. Catalyst-Dependent Chemoselective Formal Insertion of Diazo Compounds into C-C or C-H Bonds of 1,3-Dicarbonyl Compounds.

    Science.gov (United States)

    Liu, Zhaohong; Sivaguru, Paramasivam; Zanoni, Giuseppe; Anderson, Edward A; Bi, Xihe

    2018-05-08

    A catalyst-dependent chemoselective one-carbon insertion of diazo compounds into the C-C or C-H bonds of 1,3-dicarbonyl species is reported. In the presence of silver(I) triflate, diazo insertion into the C(=O)-C bond of the 1,3-dicarbonyl substrate leads to a 1,4-dicarbonyl product containing an all-carbon α-quaternary center. This reaction constitutes the first example of an insertion of diazo-derived carbenoids into acyclic C-C bonds. When instead scandium(III) triflate was applied as the catalyst, the reaction pathway switched to formal C-H insertion, affording 2-alkylated 1,3-dicarbonyl products. Different reaction pathways are proposed to account for this powerful catalyst-dependent chemoselectivity. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Diallyl phthalate (DAP) solid state nuclear track detector

    CERN Document Server

    Koguchi, Y; Ashida, T; Tsuruta, T

    2003-01-01

    Diallyl phthalate (DAP) solid state nuclear track detector is suitable for detecting heavy ions such as fission fragments, because it is insensitive to right ions such as alpha particles and protons. Detection efficiency of fission tracks is about 100%, which is unaffected under conditions below 240degC lasting for 1h or below 1 MGy of gamma-ray irradiation. Optimum etching condition for the DAP detector for detection of fission fragments is 2-4 h using 30% KOH aqueous solution at 90degC or 8-15 min using PEW-65 solution at 60degC. DAP detector is useful in detecting induced fission tracks for dating of geology or measuring intense heavy ions induced by ultra laser plasma. The fabrication of copolymers of DAP and CR-39 makes it possible to control the discrimination level for detection threshold of heavy ions. (author)

  13. Bacterial production of site specific {sup 13}C labeled phenylalanine and methodology for high level incorporation into bacterially expressed recombinant proteins

    Energy Technology Data Exchange (ETDEWEB)

    Ramaraju, Bhargavi; McFeeters, Hana; Vogler, Bernhard; McFeeters, Robert L., E-mail: robert.mcfeeters@uah.edu [University of Alabama in Huntsville, Department of Chemistry (United States)

    2017-01-15

    Nuclear magnetic resonance spectroscopy studies of ever larger systems have benefited from many different forms of isotope labeling, in particular, site specific isotopic labeling. Site specific {sup 13}C labeling of methyl groups has become an established means of probing systems not amenable to traditional methodology. However useful, methyl reporter sites can be limited in number and/or location. Therefore, new complementary site specific isotope labeling strategies are valuable. Aromatic amino acids make excellent probes since they are often found at important interaction interfaces and play significant structural roles. Aromatic side chains have many of the same advantages as methyl containing amino acids including distinct {sup 13}C chemical shifts and multiple magnetically equivalent {sup 1}H positions. Herein we report economical bacterial production and one-step purification of phenylalanine with {sup 13}C incorporation at the Cα, Cγ and Cε positions, resulting in two isolated {sup 1}H-{sup 13}C spin systems. We also present methodology to maximize incorporation of phenylalanine into recombinantly overexpressed proteins in bacteria and demonstrate compatibility with ILV-methyl labeling. Inexpensive, site specific isotope labeled phenylalanine adds another dimension to biomolecular NMR, opening new avenues of study.

  14. 6 CFR 13.45 - Deposit in Treasury of United States.

    Science.gov (United States)

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 false Deposit in Treasury of United States. 13.45 Section 13.45 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY PROGRAM FRAUD CIVIL REMEDIES § 13.45 Deposit in Treasury of United States. All amounts collected pursuant to this part...

  15. A facile synthesis of Li_2Fe_1_/_3Mn_1_/_3Ni_1_/_3SiO_4/C composites as cathode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Yang, Rong; Wang, Liqing; Deng, Kunfa; Lv, Mengni; Xu, Yunhua

    2016-01-01

    The novel Li_2Fe_1_/_3Mn_1_/_3Ni_1_/_3SiO_4/C has been successfully synthesized by a feasible solution process in ternary system. The spherical carbon-coated composites are obtained using a heat treatment in the presence of sucrose. X-ray diffraction (XRD) diffractogram displays that the Li_2Fe_1_/_3Mn_1_/_3Ni_1_/_3SiO_4/C crystallized in an orthorhombic structure with a space group of Pmn21. The energy-dispersive X-ray spectroscopy mappings indicate that Fe, Mn and Ni elements are distributed homogenously in Li_2Fe_1_/_3Mn_1_/_3Ni_1_/_3SiO_4/C nano-spherical particle with size less than 50 nm. The lithium storage capacity and cycling performance of the Li_2Fe_1_/_3Mn_1_/_3Ni_1_/_3SiO_4/C presents good results when tested as cathode materials in lithium cells at room temperature. It delivers an initial discharge capacity of 181.4 mAh g"−"1 and a discharge capacity of 172.9 mAh g"−"1 after 20 cycles at 0.1C in the voltage range of 1.5–4.6V. Furthermore, it also exhibits an excellent rate capability with a capacity under different current densities of about 144.0 mAh g"−"1 (0.2 C), 117.9 mAh g"−"1 (0.5 C), 106.1 mAh g"−"1 (1 C), respectively and a good capacity cycling maintenance of 153.7 mAh g"−"1 after 60 cycles. Above results indicate that the spherical Li_2Fe_1_/_3Mn_1_/_3Ni_1_/_3SiO_4/C becomes a very promising candidate for cathode material in lithium-ion batteries. - Highlights: • Li_2Fe_1_/_3Mn_1_/_3Ni_1_/_3SiO_4/C was obtained by solution process in a ternary system. • The material was pure phase ternary solid solution with tetrahedral morphology. • The spherical particle size was less than 50 nm with graphitized carbon coating. • The nanocomposite revealed high discharge capacity and excellent rate capability.

  16. Impact of transamination reactions and protein turnover on labeling dynamics in C-13-labeling experiments

    DEFF Research Database (Denmark)

    Grotkjær, Thomas; Åkesson, M.; Christensen, Bjarke

    2004-01-01

    A dynamic model describing carbon atom transitions in the central metabolism of Saccharomyces cerevisiae is used to investigate the influence of transamination reactions and protein turnover on the transient behavior of C-13-labeling chemostat experiments. The simulations performed suggest...... that carbon exchange due to transamination and protein turnover can significantly increase the required time needed for metabolites in the TCA cycle to reach isotopic steady state, which is in agreement with published experimental observations. On the other hand, transamination and protein turnover will speed...... behavior until after three residence times. These observations suggest that greater caution should be used while also pointing to new opportunities in the design and interpretation of C-13-labeling experiments....

  17. Trends in digital I and C for nuclear power plants

    International Nuclear Information System (INIS)

    Cook, B.M.

    2000-01-01

    Over the past decade, large-scale digital I and C systems have been installed