WorldWideScience

Sample records for through-space 13c 19f

  1. 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

  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. Solvent effect in implicit/explicit model on FT-IR, 1H, 13C and 19F NMR, UV-vis and fluorescence spectra, linear, second- and third-nonlinear optical parameters of 2-(trifluoromethyl)benzoic acid: Experimental and computational study

    Science.gov (United States)

    Avcı, Davut; Altürk, Sümeyye; Tamer, Ömer; Kuşbazoğlu, Mustafa; Atalay, Yusuf

    2017-09-01

    FT-IR, 1H, 13C and 19F NMR, UV-vis and fluorescence spectra for 2-(trifluoromethyl)benzoic acid (2-TFMBA) were recorded. DFT//B3LYP/6-31++G(d,p) calculations were used to determine the optimized molecular geometry, vibrational frequencies, 1H, 13C and 19F GIAO-NMR chemical shifts of 2-TFMBA. The detailed assignments of vibrational frequencies were carried out on the basis of potential energy distribution (PED) by using VEDA program. TD-DFT/B3LYP/6-31++G(d,p) calculations with the PCM (polarizable continuum model) in ethanol and DMSO solvents based on implicit/explicit model and gas phase in the excited state were employed to investigate UV-vis absorption and fluorescence emission wavelengths. The UV-vis and emission spectra were given in ethanol and DMSO solvents, and the major contributions to the electronic transitions were obtained. In addition, the NLO parameters (β, γ and χ(3)) and frontier molecular orbital energies of 2-TFMBA were calculated by using B3LYP/6-31++G(d,p) level. The NLO parameters of 2-TFMBA were compared with that of para-Nitroaniline (pNA) and urea which are the typical NLO materials. The refractive index (n) is calculated by using the Lorentz-Lorenz equation to observe polarization behavior of 2-TFMBA in DMSO and ethanol solvents. In order to investigate intramolecular and hydrogen bonding interactions, NBO calculations were also performed by the same level. To sum up, considering the well-known biological role, photochemical properties of 2-TFMBA were discussed.

  4. Transverse excitations of 19F

    International Nuclear Information System (INIS)

    Donne, A.J.H.

    1985-01-01

    In this thesis aspects of the structure of the nucleus 19 F are discussed as a result of transverse electron-scattering experiments, with emphasis on the ground state. The magnetization distribution of this state has been obtained from the measurement of electrons scattered from 19 F at backward angles. An introduction to the electron-scattering formalism is presented briefly together with the interpretation of electron-scattering results in terms of the nuclear shell model. The experimental apparatus for the measurement of electron scattering through an angle of 180 0 is described. This instrumentation has been installed in the low-energy facility (LEF) at NIKHEF-K. Simultaneously with the study of the magnetic ground state distribution of 19 F, also excited states of this nucleus up to an energy of 4.4 MeV have been investigated, mainly from data obtained in the EMIN station. Also for these states, the shell-model calculations have been the guide to determine their structure. (Auth.)

  5. Photoproton cross section for /sup 19/F

    Energy Technology Data Exchange (ETDEWEB)

    Tsubota, H [Tohoku Univ., Sendai (Japan). Coll. of General Education; Kawamura, N; Oikawa, S; Uegaki, J I

    1975-02-01

    Proton energy spectra have been measured at 90/sup 0/ for the /sup 19/F(e,e'p)/sup 18/O reaction in the giant resonance region. The (..gamma..,p/sub 0/) and (..gamma..,p/sub 1/) differential cross sections are extracted from the proton energy spectra by using virtual-photon spectra. The integrated differential cross section of the (..gamma..,p/sub 0/) and (..gamma..,p/sub 1/) reactions are 1.80+-0.27 and 0.50+-0.45 MeV-mb/sr, respectively. The results are discussed with the shell model theory by comparing with the (..gamma..,p/sub 0/) cross section of the neighboring 4n-nucleus /sup 20/Ne. A significant increase of the proton yield leaving the non-ground states is found at 25 MeV of the incident electron energy. This is discussed in terms of the core excitation effect.

  6. Fluorinated Polyurethane Scaffolds for 19F Magnetic Resonance Imaging

    NARCIS (Netherlands)

    Lammers, Twan; Mertens, Marianne E.; Schuster, Philipp; Rahimi, Khosrow; Shi, Yang; Schulz, Volkmar; Kuehne, Alexander J.C.; Jockenhoevel, Stefan; Kiessling, Fabian

    2017-01-01

    Researchers used fluorinated polyurethane scaffolds for 19F magnetic resonance imaging. They generated a novel fluorinated polymer based on thermoplastic polyurethane (19F -TPU) which possesses distinct properties rendering it suitable for fluorine-based MRI. The 19F -TPU is synthesized from a

  7. Study of 19F and 19Ne mirror nuclei

    International Nuclear Information System (INIS)

    Lebrun, Claude.

    1976-01-01

    The electromagnetic properties of the mirror nuclei 19 F and 19 Ne were studied using the 18 O(d,nγ) 19 F, 17 O( 3 He,nγ) 19 Ne and 19 F(p,nγ) 19 Ne reactions. Lifetimes of 8 levels in 19 F and 11 levels in 19 Ne have been measured using the Doppler shift attenuation method. Weak and strong components of M 1 , E 1 and E 2 transition strengths are compared with shell model predictions. M 1 and E 2 transition strengths of conjugated nuclei (A=18 to A=34) are compiled and compared with wide configuration space shell models [fr

  8. Detection sensitivity of fluorine in dental enamel through the 19F(p,psup(')γ)19F reaction

    International Nuclear Information System (INIS)

    Papper, C.S.; Chittleborough, G.; Kennett, S.R.; Chaudhri, M.A.

    1978-01-01

    The total cross sections for production of 109 and 197 keV gamma rays in the reaction 19 F(p,psup(')γ) 19 F have been measured, over a range of energies up to 4.3 MeV. From these cross sections, the thick detection sensitivities for a uniform distribution of fluorine in dental enamel have been calculated

  9. Development of 19F-NMR chemical shift detection of DNA B-Z equilibrium using 19F-NMR.

    Science.gov (United States)

    Nakamura, S; Yang, H; Hirata, C; Kersaudy, F; Fujimoto, K

    2017-06-28

    Various DNA conformational changes are in correlation with biological events. In particular, DNA B-Z equilibrium showed a high correlation with translation and transcription. In this study, we developed a DNA probe containing 5-trifluoromethylcytidine or 5-trifluoromethylthymidine to detect DNA B-Z equilibrium using 19 F-NMR. Its probe enabled the quantitative detection of B-, Z-, and ss-DNA based on 19 F-NMR chemical shift change.

  10. In vivo19F MR imaging and spectroscopy for the BNCT optimization

    International Nuclear Information System (INIS)

    Porcari, P.; Capuani, S.; D'Amore, E.; Lecce, M.; La Bella, A.; Fasano, F.; Migneco, L.M.; Campanella, R.; Maraviglia, B.; Pastore, F.S.

    2009-01-01

    The aim of this study was to evaluate in vivo the boron biodistribution and pharmacokinetics of 4-borono-2-fluorophenylalanine ( 19 F-BPA) using 19 F MR Imaging ( 19 F MRI) and Spectroscopy ( 19 F MRS). The correlation between the results obtained by both techniques, 19 F MRI on rat brain and 19 F MRS on blood samples, showed the maximum 19 F-BPA uptake in C6 glioma model at 2.5 h after infusion determining the optimal irradiation time. Moreover, the effect of L-DOPA as potential enhancer of 19 F-BPA tumour intake was assessed using 19 F MRI.

  11. 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.

  12. Dynamic polarization of 19F in a fluorinated alcohol

    International Nuclear Information System (INIS)

    Hill, D.; Kasprzyk, T.; Jarmer, J.J.; Penttilae, S.; Krumpolc, M.; Hoffmann, G.W.; Purcell, M.

    1988-01-01

    We have studied microwave dynamic cooling of 19 F and 1 H nuclei in mixtures of 1,1,1,3,3,3-hexafluoro-2-propanol and water, doped with Cr(V) complex. Equal spin temperatures of the two nuclei are produced, and the highest spin polarizations (/approximately/80%) are found in mixtures near the eutectic ratio. The high fluorine content and polarization make this a suitable material for polarized nuclear scattering experiments. 11 refs., 3 figs., 1 tab

  13. Fragment-Linking Approach Using (19)F NMR Spectroscopy To Obtain Highly Potent and Selective Inhibitors of β-Secretase.

    Science.gov (United States)

    Jordan, John B; Whittington, Douglas A; Bartberger, Michael D; Sickmier, E Allen; Chen, Kui; Cheng, Yuan; Judd, Ted

    2016-04-28

    Fragment-based drug discovery (FBDD) has become a widely used tool in small-molecule drug discovery efforts. One of the most commonly used biophysical methods in detecting weak binding of fragments is nuclear magnetic resonance (NMR) spectroscopy. In particular, FBDD performed with (19)F NMR-based methods has been shown to provide several advantages over (1)H NMR using traditional magnetization-transfer and/or two-dimensional methods. Here, we demonstrate the utility and power of (19)F-based fragment screening by detailing the identification of a second-site fragment through (19)F NMR screening that binds to a specific pocket of the aspartic acid protease, β-secretase (BACE-1). The identification of this second-site fragment allowed the undertaking of a fragment-linking approach, which ultimately yielded a molecule exhibiting a more than 360-fold increase in potency while maintaining reasonable ligand efficiency and gaining much improved selectivity over cathepsin-D (CatD). X-ray crystallographic studies of the molecules demonstrated that the linked fragments exhibited binding modes consistent with those predicted from the targeted screening approach, through-space NMR data, and molecular modeling.

  14. Detection of psychoactive drugs using 19F MR spectroscopy

    International Nuclear Information System (INIS)

    Bartels, M.; Albert, K.

    1995-01-01

    In vivo 19 F resonance spectroscopy measurements of tri fluorinated neuroleptics (flu phenazine and tri fluoperazine) and later tri fluorinated antidepressants (fluoxetine and fluvoxamine) began with animal experiments in 1983. Using rats which have been treated with high oral doses of flu phenazine over a period of three weeks at the beginning of these experiments the measurement time was very long (up to 10 h). The application of better techniques using surface coils led to a marked improvement of the signal noise ratio and measurement times in animal experiments could be reduced to minutes. These results encouraged us and other groups to perform experiments in humans to detect and try to estimate brain levels of tri fluorinated neuroleptics and antidepressants. The present data of several research groups demonstrate that 19 F MR spectroscopy has the potential of becoming a valuable tool for monitoring drug levels at the site of action. The extension of the animal studies to humans might facilitate a better treatment of schizophrenic and depressive patients. (author)

  15. Regional tumor oximetry: 19F NMR spectroscopy of hexafluorobenzene

    International Nuclear Information System (INIS)

    Hunjan, Sandeep; Mason, Ralph P.; Constantinescu, Anca; Peschke, Peter; Hahn, Eric W.; Antich, Peter P.

    1998-01-01

    Purpose: An accurate method for monitoring oxygen tension (pO 2 ) of individual tumors could be valuable for optimizing treatment plans. We have recently shown that 19 F nuclear magnetic resonance (NMR) spin-lattice relaxometry of hexafluorobenzene (HFB) provides a highly sensitive indicator of tumor oxygenation. We have now refined the methodology to provide enhanced precision, and applied the method to investigate dynamic changes in tumor oxygenation. Methods and Materials: Dunning prostate adenocarcinoma R3327-AT1 was grown in the form of pedicles on the foreback of male Copenhagen rats. When the tumors reached ≅1 cm diameter, HFB (20 μl) was administered, either centrally or peripherally, by direct intratumoral (IT) injection. Local pO 2 was determined using pulse-burst saturation recovery (PBSR) 19 F NMR spectroscopy on the basis of the spin-lattice relaxation rate, R1. Results: Interrogation of the central region of tumors provided typical values in the range pO 2 = 1.4-6.4 mmHg, with a typical stability of ±2 mmHg over a period of 20 min, when rats breathed 33% O 2 . Altering the inhaled gas to oxygen or carbogen (95% O 2 /5% CO 2 ) produced no significant change. In contrast, interrogation of tumor periphery indicated baseline pO 2 in the range 7.9-78.9 mmHg. Altering inspired gas produced significant changes (p 2 or carbogen, although the change was generally greater with carbogen. In each case, pO 2 returned to baseline within 16 min of returning the inhaled gas to baseline. Conclusion: We believe this method provides a valuable new approach with the requisite precision and accuracy to investigate tumor pO 2

  16. Statistical Analysis Of Tank 19F Floor Sample Results

    International Nuclear Information System (INIS)

    Harris, S.

    2010-01-01

    Representative sampling has been completed for characterization of the residual material on the floor of Tank 19F as per the statistical sampling plan developed by Harris and Shine. Samples from eight locations have been obtained from the tank floor and two of the samples were archived as a contingency. Six samples, referred to in this report as the current scrape samples, have been submitted to and analyzed by SRNL. This report contains the statistical analysis of the floor sample analytical results to determine if further data are needed to reduce uncertainty. Included are comparisons with the prior Mantis samples results to determine if they can be pooled with the current scrape samples to estimate the upper 95% confidence limits (UCL95%) for concentration. Statistical analysis revealed that the Mantis and current scrape sample results are not compatible. Therefore, the Mantis sample results were not used to support the quantification of analytes in the residual material. Significant spatial variability among the current scrape sample results was not found. Constituent concentrations were similar between the North and South hemispheres as well as between the inner and outer regions of the tank floor. The current scrape sample results from all six samples fall within their 3-sigma limits. In view of the results from numerous statistical tests, the data were pooled from all six current scrape samples. As such, an adequate sample size was provided for quantification of the residual material on the floor of Tank 19F. The uncertainty is quantified in this report by an UCL95% on each analyte concentration. The uncertainty in analyte concentration was calculated as a function of the number of samples, the average, and the standard deviation of the analytical results. The UCL95% was based entirely on the six current scrape sample results (each averaged across three analytical determinations).

  17. 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.

  18. 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

  19. 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

  20. Novel 19F MRS/I nanoprobe based on pH-responsive PEGylated nanogel. pH-dependent 19F magnetic resonance studies

    International Nuclear Information System (INIS)

    Oishi, Motoi; Sumitani, Shogo; Nagasaki, Yukio; Bronich, Tatiana K.; Kabanov, Alexander V.; Boska, Michael D.

    2009-01-01

    The pH-responsive PEGylated nanogels composed of the cross-linked poly[2-(N,N-diethylamino)ethyl methacrylate]-co-poly(2,2,2-trifluoroethyl methacrylate) gel core showed a remarkable on-off regulation of 19 F magnetic resonance signal intensity (T 2 values) as well as signal-to-noise ratios in response to extracellular pH 6.5 of tumor environment under 19 F magnetic resonance spectroscopic imaging (MRS/I), demonstrating the utility of the PEGylated nanogels as solid tumor-specific 19 F MRI/S nanoprobes. (author)

  1. 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.

  2. 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.

  3. Measurement of the fluorine content of three NBS standard reference materials by use of the /sup 19/F(p, p'. gamma. )/sup 19/F reaction

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, A L; Kraner, H W; Shroy, R E; Jones, K W [Brookhaven National Lab., Upton, NY (USA)

    1984-08-01

    The fluorine contents of National Bureau of Standards (NBS) Standard Reference Materials (SRM) 91, opal glass; 120b, phosphate rock; and 2671a, freeze-dried urine; have been measured using the /sup 19/F(p,p'..gamma..)/sup 19/F reaction at a proton energy of 3.1 MeV. The results are in good agreement with the values certified by the NBS.

  4. 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)

  5. Ring current shifts in {sup 19}F-NMR of membrane proteins

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dongsheng, E-mail: liudsh@shanghaitech.edu.cn; Wüthrich, Kurt, E-mail: kwuthrich@shanghaitech.edu.cn [ShanghaiTech University, iHuman Institute (China)

    2016-05-15

    Fluorine-19 NMR markers are attractive reporter groups for use in studies of complex biomacromolecular systems, in particular also for studies of function-related conformational equilibria and rate processes in membrane proteins. Advantages of {sup 19}F-NMR probes include high sensitivity of the {sup 19}F chemical shifts to variations in the non-covalent environment. Nonetheless, in studies of G protein-coupled receptors (GPCR) we encountered situations where {sup 19}F chemical shifts were not responsive to conformational changes that had been implicated by other methods. This prompted us to examine possible effects of aromatic ring current fields on the chemical shifts of {sup 19}F-NMR probes used in GPCRs. Analysis of previously reported {sup 19}F-NMR data on the β{sub 2}-adrenergic receptor and mammalian rhodopsin showed that all {sup 19}F-labeling sites which manifested conformational changes are located near aromatic residues. Although ring current effects are small when compared to other known non-covalent effects on {sup 19}F chemical shifts, there is thus an indication that their contributions are significant when studying activation processes in GPCRs, since the observed activation-related {sup 19}F-NMR chemical shifts are comparable in size to the calculated ring current shifts. Considering the impact of ring current shifts may thus be helpful in identifying promising indigenous or engineered labeling sites for future {sup 19}F-NMR studies of GPCR activation, and novel information may be obtained on the nature of conformational rearrangements near the {sup 19}F-labels. It will then also be interesting to see if the presently indicated role of ring current shifts in membrane protein studies with {sup 19}F-NMR markers can be substantiated by a more extensive data base resulting from future studies.

  6. 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.

  7. Visualizing arthritic inflammation and therapeutic response by fluorine-19 magnetic resonance imaging (19F MRI

    Directory of Open Access Journals (Sweden)

    Balducci Anthony

    2012-06-01

    Full Text Available Abstract Background Non-invasive imaging of inflammation to measure the progression of autoimmune diseases, such as rheumatoid arthritis (RA, and to monitor responses to therapy is critically needed. V-Sense, a perfluorocarbon (PFC contrast agent that preferentially labels inflammatory cells, which are then recruited out of systemic circulation to sites of inflammation, enables detection by 19F MRI. With no 19F background in the host, detection is highly-specific and can act as a proxy biomarker of the degree of inflammation present. Methods Collagen-induced arthritis in rats, a model with many similarities to human RA, was used to study the ability of the PFC contrast agent to reveal the accumulation of inflammation over time using 19F MRI. Disease progression in the rat hind limbs was monitored by caliper measurements and 19F MRI on days 15, 22 and 29, including the height of clinically symptomatic disease. Naïve rats served as controls. The capacity of the PFC contrast agent and 19F MRI to assess the effectiveness of therapy was studied in a cohort of rats administered oral prednisolone on days 14 to 28. Results Quantification of 19F signal measured by MRI in affected limbs was linearly correlated with disease severity. In animals with progressive disease, increases in 19F signal reflected the ongoing recruitment of inflammatory cells to the site, while no increase in 19F signal was observed in animals receiving treatment which resulted in clinical resolution of disease. Conclusion These results indicate that 19F MRI may be used to quantitatively and qualitatively evaluate longitudinal responses to a therapeutic regimen, while additionally revealing the recruitment of monocytic cells involved in the inflammatory process to the anatomical site. This study may support the use of 19F MRI to clinically quantify and monitor the severity of inflammation, and to assess the effectiveness of treatments in RA and other diseases with an inflammatory

  8. 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

  9. 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.

  10. Structural Studies of Bcl-xL/ligand Complexes using {sup 19}F NMR

    Energy Technology Data Exchange (ETDEWEB)

    Yu Liping; Hajduk, Philip J.; Mack, Jamey; Olejniczak, Edward T. [GPRD, Abbott Laboratories, Pharmaceutical Discovery Division (United States)], E-mail: Edward.olejniczak@abbott.com

    2006-04-15

    Fluorine atoms are often incorporated into drug molecules as part of the lead optimization process in order to improve affinity or modify undesirable metabolic and pharmacokinetic profiles. From an NMR perspective, the abundance of fluorinated drug leads provides an exploitable niche for structural studies using {sup 19}F NMR in the drug discovery process. As {sup 19}F has no interfering background signal from biological sources, {sup 19}F NMR studies of fluorinated drugs bound to their protein receptors can yield easily interpretable and unambiguous structural constraints. {sup 19}F can also be selectively incorporated into proteins to obtain additional constraints for structural studies. Despite these advantages, {sup 19}F NMR has rarely been exploited for structural studies due to its broad lines in macromolecules and their ligand complexes, leading to weak signals in {sup 1}H/{sup 19}F heteronuclear NOE experiments. Here we demonstrate several different experimental strategies that use {sup 19}F NMR to obtain ligand-protein structural constraints for ligands bound to the anti-apoptotic protein Bcl-xL, a drug target for anti-cancer therapy. These examples indicate the applicability of these methods to typical structural problems encountered in the drug development process.

  11. [Primary study on fluro [ 19F] berberine derivative for human hepatocellular carcinoma targetting in vitro].

    Science.gov (United States)

    Zhang, Tong; Wu, Xiaoai; Cai, Huawei; Liang, Meng; Fan, Chengzhong

    2017-04-01

    [ 18 F]HX-01, a Fluorine-18 labeled berberine derivative, is a potential positron emission tomography (PET) tumor imaging agent, while [ 19 F]HX-01 is a nonradioactive reference substance with different energy state and has the same physical and chemical properties. In order to collect data for further study of [ 18 F]HX-01 PET imaging of hepatocellular carcinoma in vivo , this study compared the uptake of [ 19 F]HX-01 by human hepatocellular carcinoma and normal hepatocytes in vitro . The target compound, [ 19 F]HX-01, was synthesized in one step using berberrubine and 3-fluoropropyl 4-methylbenzenesulfonate. Cellular uptake and localization of [ 19 F]HX-01 were performed by a fluorescence microscope in human hepatocellular carcinoma HepG2, SMMC-7721 and human normal hepatocyte HL-7702. Cellular proliferation inhibition and cell cytotoxicity assay of the [ 19 F]HX-01 were conducted using cell counting kit-8 (CCK-8) on HepG2, SMMC-7721 and HL-7702 cells. Fluorescent microscopy showed that the combining ability of [ 19 F]HX-01 to the carcinoma SMMC-7721 and HepG2 was higher than that to the normal HL-7702. Cellular proliferation inhibition assay demonstrated that [ 19 F]HX-01 leaded to a dose-dependent inhibition on SMMC-7721, HepG2, and HL-7702 proliferation. Cell cytotoxicity assay presented that the cytotoxicity of [ 19 F]HX-01 to SMMC-7721 and HepG2 was obviously higher than that to HL-7702. This in vitro study showed that [ 19 F]HX-01 had a higher selectivity on human hepatocellular carcinoma cells (SMMC-7721, HepG2) but has less toxicity to normal hepatocytes (HL-7702). This could set up the idea that the radioactive reference substance [ 18 F]HX-01 may be worthy of further development as a potential molecular probe targeting human hepatocellular carcinoma using PET.

  12. 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)

  13. 19F labelled dextrans and antibodies as NMR imaging and spectroscopy agents

    International Nuclear Information System (INIS)

    Antich, P.P.; Kulkarni, P.V.

    1993-01-01

    A method is described of NMR imaging or spectroscopy, comprising the steps of administering to a living subject a 19 F labelled NMR agent, the NMR agent comprising (a) a transport polymer selected from the group consisting of dextran polymers and amino dextrans, having a molecular weight between approximately 100 d and 500 kd, and antibodies and fragments thereof, and (b) a 19F-containing sensor moiety selected from the group consisting of fluorinated alkyls, fluorinated acetates, fluoroaniline, and fluoroalkyl phosphonates, in an amount effective to provide a detectable NMR signal; and then detecting the 19 F NMR signal produced

  14. 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.

  15. 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)

  16. 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)

  17. Application of NMR Screening Methods with 19F Detection to Fluorinated Compounds Bound to Proteins

    Directory of Open Access Journals (Sweden)

    Kazuo Furihata

    2017-12-01

    Full Text Available The combinational use of one-dimensional (1D NMR-based screening techniques with 1H and 19F detections were applied to a human serum albumin–diflunisal complex. Since most NMR screening methods observe 1H spectra, the overlapped 1H signals were unavailable in the binding epitope mapping. However, the NMR experiments with 19F detection can be used as an effective complementary method. For the purpose of identifying the 1H and 19F binding epitopes of diflunisal, this paper carries out a combinatorial analysis using 1H{1H} and 19F{1H} saturation transfer difference experiments. The differences of the 1H-inversion recovery rates with and without target irradiation are also analyzed for a comprehensive interpretation of binding epitope mapping.

  18. 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)

  19. 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)

  20. 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.

  1. Double-tuned radiofrequency coil for (19)F and (1)H imaging.

    Science.gov (United States)

    Otake, Yosuke; Soutome, Yoshihisa; Hirata, Koji; Ochi, Hisaaki; Bito, Yoshitaka

    2014-01-01

    We developed a double-tuned radiofrequency (RF) coil using a novel circuit method to double tune for fluorine-19 (19F) and 1H magnetic resonance imaging, whose frequencies are very close to each other. The RF coil consists of 3 parallel-connected series inductor capacitor circuits. A computer simulation for our double-tuned RF coil with a phantom demonstrated that the coil has tuned resonant frequency and high sensitivity for both 19F and 1H. Drug distribution was visualized at 7 tesla using this RF coil and a rat administered perfluoro 15-crown-5-ether emulsion. The double-tune RF coil we developed may be a powerful tool for 19F and 1H imaging.

  2. Electronic stopping powers for fluorine ions in 19F+-implanted silver gallium diselenide

    International Nuclear Information System (INIS)

    Liu Xiangdong; Xia Yueyuan; Li Feng; Lu Qingming; Huang Boda

    2004-01-01

    Electronic stopping powers for 80-350 keV 19 F ions in AgGaSe 2 were obtained by range measurement. Depth profiles of 19 F in AgGaSe 2 were measured by using the 19 F(p,αγ) 16 O resonant nuclear reaction at E R =872.1 keV. A proper convolution calculation method was used to extract the true distribution of fluorine from the experimental excitation yield curves. The electronic stopping powers were derived through fitting the projected range distributions, simulated by using the TRIM/XLL code, to the experimentally measured range distributions. The electronic stopping cross-sections were compared with those obtained from Monte Carlo simulation codes

  3. Electronic stopping powers for fluorine ions in {sup 19}F{sup +}-implanted silver gallium diselenide

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiangdong E-mail: xdliu@sdu.edu.cn; Xia Yueyuan; Li Feng; Lu Qingming; Huang Boda

    2004-08-01

    Electronic stopping powers for 80-350 keV {sup 19}F ions in AgGaSe{sub 2} were obtained by range measurement. Depth profiles of {sup 19}F in AgGaSe{sub 2} were measured by using the {sup 19}F(p,{alpha}{gamma}){sup 16}O resonant nuclear reaction at E{sub R}=872.1 keV. A proper convolution calculation method was used to extract the true distribution of fluorine from the experimental excitation yield curves. The electronic stopping powers were derived through fitting the projected range distributions, simulated by using the TRIM/XLL code, to the experimentally measured range distributions. The electronic stopping cross-sections were compared with those obtained from Monte Carlo simulation codes.

  4. In vivo imaging of stepwise vessel occlusion in cerebral photothrombosis of mice by 19F MRI.

    Directory of Open Access Journals (Sweden)

    Gesa Weise

    Full Text Available (19F magnetic resonance imaging (MRI was recently introduced as a promising technique for in vivo cell tracking. In the present study we compared (19F MRI with iron-enhanced MRI in mice with photothrombosis (PT at 7 Tesla. PT represents a model of focal cerebral ischemia exhibiting acute vessel occlusion and delayed neuroinflammation.Perfluorocarbons (PFC or superparamagnetic iron oxide particles (SPIO were injected intravenously at different time points after photothrombotic infarction. While administration of PFC directly after PT induction led to a strong (19F signal throughout the entire lesion, two hours delayed application resulted in a rim-like (19F signal at the outer edge of the lesion. These findings closely resembled the distribution of signal loss on T2-weighted MRI seen after SPIO injection reflecting intravascular accumulation of iron particles trapped in vessel thrombi as confirmed histologically. By sequential administration of two chemically shifted PFC compounds 0 and 2 hours after illumination the different spatial distribution of the (19F markers (infarct core/rim could be visualized in the same animal. When PFC were applied at day 6 the fluorine marker was only detected after long acquisition times ex vivo. SPIO-enhanced MRI showed slight signal loss in vivo which was much more prominent ex vivo indicative for neuroinflammation at this late lesion stage.Our study shows that vessel occlusion can be followed in vivo by (19F and SPIO-enhanced high-field MRI while in vivo imaging of neuroinflammation remains challenging. The timing of contrast agent application was the major determinant of the underlying processes depicted by both imaging techniques. Importantly, sequential application of different PFC compounds allowed depiction of ongoing vessel occlusion from the core to the margin of the ischemic lesions in a single MRI measurement.

  5. 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)

  6. Projectile fragmentation in reactions induced by 19F at low energy

    International Nuclear Information System (INIS)

    Pop, A.; Cenja, M.; Duma, M.; Dumitrescu, R.; Isbasescu, A.; Magda, M.T.

    1984-09-01

    Light-particle emission was studied in 19 F + 12 C and 19 F + 27 Al reactions at 72 MeV. The spectral shape shows an important breakup component in the case of 2 H, 3 H and 3 He while in the case of 1 H and 4 He the statistical contribution is predominant. The emission of 6 He, 6 Li, 7 Li and 9 Be was also observed and explained by the projectile breakup mechanism within the Serber model. The experimental isotope yields are in good agreement with the theoretical predictions of the Friedman model. (authors)

  7. 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)

  8. 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.

  9. 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

  10. Synthesis and Characterization of a Magnetically Active 19F Molecular Beacon.

    Science.gov (United States)

    Dempsey, Megan E; Marble, Hetal D; Shen, Tun-Li; Fawzi, Nicolas L; Darling, Eric M

    2018-02-21

    Gene expression is used extensively to describe cellular characteristics and behaviors; however, most methods of assessing gene expression are unsuitable for living samples, requiring destructive processes such as fixation or lysis. Recently, molecular beacons have become a viable tool for live-cell imaging of mRNA molecules in situ. Historically, beacon-mediated imaging has been limited to fluorescence-based approaches. We propose the design and synthesis of a novel molecular beacon for magnetic resonance detection of any desired target nucleotide sequence. The biologically compatible synthesis incorporates commonly used bioconjugation reactions in aqueous conditions and is accessible for laboratories without extensive synthesis capabilities. The resulting beacon uses fluorine ( 19 F) as a reporter, which is broadened, or turned "off", via paramagnetic relaxation enhancement from a stabilized nitroxide radical spin label when the beacon is not bound to its nucleic acid target. Therefore, the 19 F NMR signal of the beacon is quenched in its hairpin conformation when the spin label and the 19 F substituent are held in proximity, but the signal is recovered upon beacon hybridization to its specific complementary nucleotide sequence by physical separation of the radical from the 19 F reporter. This study establishes a path for magnetic resonance-based assessment of specific mRNA expression, providing new possibilities for applying molecular beacon technology in living systems.

  11. NMR 11B, 19F of hydroxofluoroborate solutions in acetic and peracetic acids

    International Nuclear Information System (INIS)

    Shchetinina, G.P.; Brovkina, O.V.; Chernyshov, B.N.

    1985-01-01

    Hydroxofluoroborate solutions in acetic and peracetic acids are studied by the 11 B, 19 F NMR method. The reactions of substitutions of acetate- and peracetate ions for nucleophilic hydroxogroups with the formation of the respective complexes are shown to occur in these solutions, with monodentate coordination of BF 3 CH 3 COO - - and BF 3 CH 3 COOO - - groups being accomplished in this case

  12. Cell Labeling for 19F MRI: New and Improved Approach to Perfluorocarbon Nanoemulsion Design

    Directory of Open Access Journals (Sweden)

    Jonathan Williams

    2013-09-01

    Full Text Available This report describes novel perfluorocarbon (PFC nanoemulsions designed to improve ex vivo cell labeling for 19F magnetic resonance imaging (MRI. 19F MRI is a powerful non-invasive technique for monitoring cells of the immune system in vivo, where cells are labeled ex vivo with PFC nanoemulsions in cell culture. The quality of 19F MRI is directly affected by the quality of ex vivo PFC cell labeling. When co-cultured with cells for longer periods of time, nanoemulsions tend to settle due to high specific weight of PFC oils (1.5–2.0 g/mL. This in turn can decrease efficacy of excess nanoemulsion removal and reliability of the cell labeling in vitro. To solve this problem, novel PFC nanoemulsions are reported which demonstrate lack of sedimentation and high stability under cell labeling conditions. They are monodisperse, have small droplet size (~130 nm and low polydispersity (<0.15, show a single peak in the 19F nuclear magnetic resonance spectrum at −71.4 ppm and possess high fluorine content. The droplet size and polydispersity remained unchanged after 160 days of follow up at three temperatures (4, 25 and 37 °C. Further, stressors such as elevated temperature in the presence of cells, and centrifugation, did not affect the nanoemulsion droplet size and polydispersity. Detailed synthetic methodology and in vitro testing for these new PFC nanoemulsions is presented.

  13. 19F-nuclear magnetic resonance spectroscopy as a tool to ...

    African Journals Online (AJOL)

    19F-nuclear magnetic resonance spectroscopy as a tool to investigate host-guest complexation of some antidepressant drugs with natural and modified cyclodextrins. Leila Shafiee Dastjerdi1* and Mojtaba Shamsipur2. 1Faculty of Science, Roudehen Branch, Islamic Azad University, Tehran, 2Department of Chemistry, ...

  14. The combined application of 1H MRI and 19F MRS to the study of cerebroprotection

    International Nuclear Information System (INIS)

    Haga, K.K.

    2000-01-01

    The research presented in this thesis focuses on the application of 1 H and 19 F nuclear magnetic resonance techniques to the evaluation of the neuroprotective and pharmacokinetic properties of a novel, nitric oxide synthase inhibitor in a rat model of stroke. Although there is a growing body of research on the application of 19 F magnetic resonance spectroscopy techniques to the study of psychotropic agents, this is the first attempt to apply these methods to the evaluation of an agent being developed for cerebroprotection. TRIM, 1-(2-trifluoromethylphenyl) imidazole, is a selective inhibitor of the neuronal form of nitric oxide synthase in the rat and mouse brain. The first portion of this thesis demonstrates TRIM's neuroprotective properties when administered post-occlusion in the middle cerebral artery occlusion model of focal cerebral ischaemia. In addition, these neuroprotective effects may be eliminated by the co-administration of L-arginine, a nitric oxide precursor, indicating a role for neuronal nitric oxide synthase in ischaemic damage. 1 H magnetic resonance imaging at 24 hours post-occlusion indicates a 40% reduction in lesion volume following TRIM administration as compared to the saline control group. The second part of this thesis pertains to the development and application of 19 F MRS methods, in vivo and in vitro, to enable the investigator to monitor and quantify TRIM in the rat CNS pre and post-occlusion. In this section, 19 F MRS studies were conducted to measure the in vivo T 1 and T 2 relaxation parameters and subsequently, the concentration of TRIM achieved in the rat CNS over an 8 hour measuring period. From this data, the in vivo pharmacokinetics of TRIM were evaluated and applied to the neuroprotective strategy in cerebral ischaemia. In vitro measurements of TRIM concentrations in the rat CNS were compared to the in vivo concentration calculations to evaluate the reliability of TRIM quantification using the combined coils system. Finally

  15. 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)

  16. 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...

  17. The metabolism of 2-trifluormethylaniline and its acetanilide in the rat by 19F NMR monitored enzyme hydrolysis and 1H/19F HPLC-NMR spectroscopy.

    Science.gov (United States)

    Tugnait, M; Lenz, E M; Hofmann, M; Spraul, M; Wilson, I D; Lindon, J C; Nicholson, J K

    2003-01-01

    The urinary excretion profile and identity of the metabolites of 2-trifluoromethyl aniline (2-TFMA) and 2-trifluoromethyl acetanilide (2-TFMAc), following i.p. administration to the rat at 50 mg kg(-1), were determined using a combination of 19F NMR monitored enzyme hydrolysis, SPEC-MS and 19F/1H HPLC-NMR. A total recovery of approximately 96.4% of the dose was excreted into the urine as seven metabolites. The major routes of metabolism were N-conjugation (glucuronidation), and ring-hydroxylation followed by sulphation (and to a lesser extent glucuronidation). The major metabolites excreted into the urine for both compounds were a labile N-conjugated metabolite (a postulated N-glucuronide) and a sulphated ring-hydroxylated metabolite (a postulated 4-amino-5-trifluoromethylphenyl sulphate) following dosing of 2-TFMA. These accounted for approximately 53.0 and 31.5% of the dose, respectively. This study identifies problems on sample component instability in the preparation and analysis procedures.

  18. 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

  19. 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)

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. Magnetic vacancies; simulations and TDPAD experiments with 19 F in Al(x) Fe(1-x)

    International Nuclear Information System (INIS)

    Ekwall, B.; Johansson, K.; Lidbjoerk, P.; Lindgren, B.; Norlin, L.O.

    1984-04-01

    Al(x) Fe(1-x) alloys with less or equal 4.2 at percent have been studied by the TDPAD method utilising 19 F as probe. The hyperfine field was found to increase with 0.39(6) percent per at percent Al. A Monte Carlo simulation of the dipolar distribution, due to the missing Fe moments, agrees well with the experimental results.(author)

  5. 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

  6. 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

  7. Revisiting the metathesis of 13C-monolabeled ethane

    KAUST Repository

    Maury, Olivier; Lefort, Laurent; Vidal, Vé ronique; Thivolle-Cazat, Jean; Basset, Jean-Marie

    2010-01-01

    The metathesis of 13C-monolabeled ethane leads to the parallel occurrence of degenerate and productive reactions, affording the statistical distribution of the various product isotopomers, which can be rationalized in terms of a mechanistic reaction

  8. First evidences for 19F(α, p)22Ne at astrophysical energies

    International Nuclear Information System (INIS)

    D’Agata, G.; Spitaleri, C.; Pizzone, R.G.; Figuera, P.; Guardo, G.L.; Gulino, M.; Indelicato, I.; La Cognata, M.; Lattuada, M.; Sergi, M.L.; Blagus, S.; Mijatović, T.; Milin, M.; Miljanic, D.; Prepolec, L.; Skukan, N.; Grassi, L.; Lamia, L.; Hayakawa, S.; Kshetri, R.

    2016-01-01

    19 F experimental abundances is overestimated in respect to the theoretical one: it is therefore clear that further investigations are needed. We focused on the 19 F(α, p) 22 Ne reaction, representing the main destruction channel in He-rich environments. The lowest energy at which this reaction has been studied with direct methods is E C.M. ≈ 0.91 MeV, while the Gamow region is between 0.39 ÷ 0.8 MeV, far below the Coulomb barrier (3.8 MeV). For this reason, an experiment at Rudjer Boskovic Institute (Zagreb) was performed, applying the Trojan Horse Method. Following this method we selected the quasi-free contribution coming from 6 Li( 19 F,p 22 Ne) 2 H at E beam =6 MeV at kinematically favourable angles, and the cross section at energies 0 < E C.M. < 1.4 MeV was extracted in arbitrary units, covering the astrophysical region of interest. (paper)

  9. ^2H(^18F,p)^19F Study at 6 MeV/u

    Science.gov (United States)

    Kozub, R. L.; Nesaraja, C. D.; Moazen, B. H.; Scott, J. P.; Bardayan, D. W.; Blackmon, J. C.; Gross, C. J.; Shapira, D.; Smith, M. S.; Batchelder, J. C.; Brune, C. R.; Champagne, A. E.; Sahin, L.; Cizewski, J. A.; Thomas, J. S.; Davinson, T.; Woods, P. J.; Greife, U.; Jewett, C.; Livesay, R. J.; Ma, Z.; Parker, P. D.

    2003-04-01

    The degree to which the (p,α) and (p,γ) reactions destroy ^18F at temperatures ˜1-4 x 10^8 K is important for understanding the synthesis of nuclei in nova explosions and for using ^18F as a monitor of nova mechanisms in gamma ray astronomy. The reactions are dominated by low-lying proton resonances near the ^18F+p threshold (E_x=6.411 MeV excitation energy in ^19Ne). To gain further information about these resonances, we have used the inverse ^18F(d,p)^19F neutron transfer reaction at the Holifield Radioactive Ion Beam Facility to selectively populate corresponding mirror states in ^19F. Proton angular distributions were measured for states in ^19F in the excitation energy range 0-9 MeV. Results and implications for the ^18F+p reactions and nuclear structure will be presented. ^1Supported by DOE. ^2ORNL is managed by UT-Battelle, LLC, for the USDOE.

  10. 2H{ 19F} REDOR for distance measurements in biological solids using a double resonance spectrometer

    Science.gov (United States)

    Grage, Stephan L.; Watts, Jude A.; Watts, Anthony

    2004-01-01

    A new approach for distance measurements in biological solids employing 2H{ 19F} rotational echo double resonance was developed and validated on 2H, 19F- D-alanine and an imidazopyridine based inhibitor of the gastric H +/K +-ATPase. The 2H- 19F double resonance experiments presented here were performed without 1H decoupling using a double resonance NMR spectrometer. In this way, it was possible to benefit from the relatively longer distance range of fluorine without the need of specialized fluorine equipment. A distance of 2.5 ± 0.3 Å was measured in the alanine derivative, indicating a gauche conformation of the two labels. In the case of the imidazopyridine compound a lower distance limit of 5.2 Å was determined and is in agreement with an extended conformation of the inhibitor. Several REDOR variants were compared, and their advantages and limitations discussed. Composite fluorine dephasing pulses were found to enhance the frequency bandwidth significantly, and to reduce the dependence of the performance of the experiment on the exact choice of the transmitter frequency.

  11. Mapping In Vivo Tumor Oxygenation within Viable Tumor by 19F-MRI and Multispectral Analysis

    Directory of Open Access Journals (Sweden)

    Yunzhou Shi

    2013-11-01

    Full Text Available Quantifying oxygenation in viable tumor remains a major obstacle toward a better understanding of the tumor microenvironment and improving treatment strategies. Current techniques are often complicated by tumor heterogeneity. Herein, a novel in vivo approach that combines 19F magnetic resonance imaging (19F-MRIR1 mapping with diffusionbased multispectral (MS analysis is introduced. This approach restricts the partial pressure of oxygen (pO2 measurements to viable tumor, the tissue of therapeutic interest. The technique exhibited sufficient sensitivity to detect a breathing gas challenge in a xenograft tumor model, and the hypoxic region measured by MS 19F-MRI was strongly correlated with histologic estimates of hypoxia. This approach was then applied to address the effects of antivascular agents on tumor oxygenation, which is a research question that is still under debate. The technique was used to monitor longitudinal pO2 changes in response to an antibody to vascular endothelial growth factor (B20.4.1.1 and a selective dual phosphoinositide 3-kinase/mammalian target of rapamycin inhibitor (GDC-0980. GDC-0980 reduced viable tumor pO2 during a 3-day treatment period, and a significant reduction was also produced by B20.4.1.1. Overall, this method provides an unprecedented view of viable tumor pO2 and contributes to a greater understanding of the effects of antivascular therapies on the tumor's microenvironment.

  12. Probe-Specific Procedure to Estimate Sensitivity and Detection Limits for 19F Magnetic Resonance Imaging.

    Directory of Open Access Journals (Sweden)

    Alexander J Taylor

    Full Text Available Due to low fluorine background signal in vivo, 19F is a good marker to study the fate of exogenous molecules by magnetic resonance imaging (MRI using equilibrium nuclear spin polarization schemes. Since 19F MRI applications require high sensitivity, it can be important to assess experimental feasibility during the design stage already by estimating the minimum detectable fluorine concentration. Here we propose a simple method for the calibration of MRI hardware, providing sensitivity estimates for a given scanner and coil configuration. An experimental "calibration factor" to account for variations in coil configuration and hardware set-up is specified. Once it has been determined in a calibration experiment, the sensitivity of an experiment or, alternatively, the minimum number of required spins or the minimum marker concentration can be estimated without the need for a pilot experiment. The definition of this calibration factor is derived based on standard equations for the sensitivity in magnetic resonance, yet the method is not restricted by the limited validity of these equations, since additional instrument-dependent factors are implicitly included during calibration. The method is demonstrated using MR spectroscopy and imaging experiments with different 19F samples, both paramagnetically and susceptibility broadened, to approximate a range of realistic environments.

  13. Probe-Specific Procedure to Estimate Sensitivity and Detection Limits for 19F Magnetic Resonance Imaging.

    Science.gov (United States)

    Taylor, Alexander J; Granwehr, Josef; Lesbats, Clémentine; Krupa, James L; Six, Joseph S; Pavlovskaya, Galina E; Thomas, Neil R; Auer, Dorothee P; Meersmann, Thomas; Faas, Henryk M

    2016-01-01

    Due to low fluorine background signal in vivo, 19F is a good marker to study the fate of exogenous molecules by magnetic resonance imaging (MRI) using equilibrium nuclear spin polarization schemes. Since 19F MRI applications require high sensitivity, it can be important to assess experimental feasibility during the design stage already by estimating the minimum detectable fluorine concentration. Here we propose a simple method for the calibration of MRI hardware, providing sensitivity estimates for a given scanner and coil configuration. An experimental "calibration factor" to account for variations in coil configuration and hardware set-up is specified. Once it has been determined in a calibration experiment, the sensitivity of an experiment or, alternatively, the minimum number of required spins or the minimum marker concentration can be estimated without the need for a pilot experiment. The definition of this calibration factor is derived based on standard equations for the sensitivity in magnetic resonance, yet the method is not restricted by the limited validity of these equations, since additional instrument-dependent factors are implicitly included during calibration. The method is demonstrated using MR spectroscopy and imaging experiments with different 19F samples, both paramagnetically and susceptibility broadened, to approximate a range of realistic environments.

  14. 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

  15. 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)

  16. 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)

  17. 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.

  18. 19F NMR method for the determination of quality of virgin olive oil

    Directory of Open Access Journals (Sweden)

    Zhou, L. L.

    2015-12-01

    Full Text Available This paper reported a potential analytical technique based on NMR spectroscopy for the determination of quality of olive oil. The model compounds with active hydrogen, including free sterols, free aliphatic alcohols, phenolics, and free fatty acids were determined by 19F NMR upon derivation with 4-fluorobenzoyl chloride. Integration of the appropriate signals of the derivatives of the compounds in the corresponding 19F NMR spectrum allows for the quantification of these compounds. 37 Samples of commercial olive oil and 5 samples of other plant oils were determined by 19F NMR. The amount of diglycerides and the ratio of 1,2-diglycerides to the total amount of diglycerides were analyzed to monitor whether extra virgin olive oil was adulterated with low price olive oil and other plant oils or not. The results showed that the total diglyceride content should not be higher than 2.5% and the ratio (D of 1,2-diglycerides to total diglycerides should be higher than 0.35 for extra virgin olive oil. This method is an easier, simpler, safer, faster and more reliable technique for the determination of the quality of olive oil and can also be extended to monitoring the quality of ordinary edible oils.En este trabajo se describe una técnica analítica basada en la espectroscopía de RMN para determinar la calidad del aceite de oliva. Los compuestos modelo con hidrógeno activo, incluyendo esteroles libres, alcoholes alifáticos libres, compuestos fenólicos, ácidos grasos libres se determinaron por 19F RMN derivatizados con cloruro de 4-fluorobenzoilo. La integración de las señales apropiadas de los derivados de los compuestos en el correspondiente espectro de 19F RMN permite la cuantificación de estos compuestos. 37 muestras de aceites de oliva comerciales y 5 muestras de otros aceites vegetales se determinaron por 19F RMN. La cantidad de diglicéridos y la proporción de los 1,2-diglicéridos a la cantidad total de diglicéridos se analizaron para

  19. {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.

  20. 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

  1. Complete and incomplete fusion dynamics in 19F + 154Sm system

    International Nuclear Information System (INIS)

    Singh, D.; Giri, Pankaj K.; Linda, Sneha B.

    2016-01-01

    Several experimental and theoretical studies based on spin distribution measurement have been carried out by using α-cluster structured projectile with different target nuclei but spin distribution measurement studies to localize the ℓ-window of CF and ICF by using non alpha cluster structured projectile scarcely exist in the literature. Therefore, to reach on some definite conclusion regarding the projectile structure and projectile energy effect on ICF dynamics especially by using non alpha cluster structured projectile, the spin distribution measurement of the evaporation residues produced through CF and ICF dynamics in the 19 F + 154 Sm system at projectile energies 110 and 100 MeV has been done

  2. A 19F NMR study of C-I....pi- halogen bonding

    DEFF Research Database (Denmark)

    Hauchecorne, Dieter; vand er Veken, Benjamin J.; Herrebout, Wouter A.

    2011-01-01

    The formation of halogen bonded complexes between toluene-d8 and the perfluoroiodopropanes 1-C3F7I and 2-C3F7I has been investigated using 19F NMR spectroscopy. For both Lewis acids, evidence was found for the formation of a C–I⋯π halogen bonded complex. The complex formed is a 1:1 type. Using sp...... results are supported by ab initio calculations at the B3LYP-PCM/6-311++G(d,p) + LanL2DZ∗ level....

  3. Analytical applications of 19F (p, αγ)16O reaction

    International Nuclear Information System (INIS)

    Arias Revollo, F.R.

    1977-11-01

    The reaction 19 F (p, αγ) 16 O was used to determine fluorine concentration in various substances. A pronounced resonance at E sub(P) = 672 KeV permitted analysis of samples at various depths. Backscattered protons were used to normalize the number of 6,13 and 7,12 MeV gamma rays emitted during sample irradiation. Comparison with gamma/particle ratios from pure substances of know fluorine concentration permits an absolute interpretation of results. The technique was applied to several human and animal tooth samples and fluorine containing minerals. (Author) [pt

  4. In vivo 7Li and 19F NMR studies of drugs in the brain

    International Nuclear Information System (INIS)

    Komoroski, Richard A.

    1999-01-01

    For various reasons, it is advantageous to measure the concentration of a psychoactive drug in the brain in vivo. Many drugs contain the element fluorine. Using 19 F NMR spectroscopy, we have studied the psychoactive drugs trifluoperazine and fluoxetine in the brain in vivo. Using 7 Li NMR, it is possible to detect lithium ion, used to treat manic depressive illness. We have measured the concentration and distribution of lithium in both human and rat brain in vivo. Measurement of drug levels in the human brain may provide a measure of therapeutic or toxic effects, as well as insight into drug metabolism and mechanism of action. (author)

  5. Metabolic 19F MRI an dynamic 18F PET for chemotherapy monitoring in experimental tumors

    International Nuclear Information System (INIS)

    Brix, G.; Haberkorn, U.; Bellemann, M.E.

    1999-01-01

    The efficient clinical use of chemotherapeutic agents requires the assessment of the uptake and metabolism of the drugs in the tumor as well as in the various organs of the body by using noninvasive imaging techniques such as magnetic resonance imaging (MRI) and positron emission tomography (PET). In this overview, we present different metabolic 19 F MRI and dynamic 18 F PET techniques for noninvasive monitoring of fluorine-containing anticancer drugs and evaluate their potentials and limitations within the framework of experimental animal studies. (orig.) [de

  6. 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

  7. Direct 13C NMR Detection in HPLC Hyphenation Mode

    DEFF Research Database (Denmark)

    Wubshet, Sileshi Gizachew; Johansen, Kenneth; Nyberg, Nils

    2012-01-01

    Solid phase extraction (SPE) was introduced as a crucial step in the HPLC-SPE-NMR technique to enable online analyte enrichment from which proton-detected NMR experiments on submicrogram amounts from complex mixtures were possible. However, the significance of direct-detected (13)C NMR experiments...... application of HPLC-SPE-NMR analysis using direct-detected (13)C NMR spectra. HPLC column loading, accumulative SPE trappings, and the effect of different elution solvents were evaluated and optimized. A column loading of approximately 600 mug of a prefractionated triterpenoid mixture, six trappings...

  8. Nuclear quadrupole interaction measurements of 19F* and 22Na* on Graphite

    International Nuclear Information System (INIS)

    Djoko-Surono, Th; Martin, Peter W

    1996-01-01

    Time differential perturbed angular distribution (TDPAD) technique has been used to investigate nuclear quadrupole interactions of 19 F * and 22 Na * in graphite. We concentrated the measurements on pseudo single crystal graphite called Highly Oriented Pyrolytic Graphite for it has an ordered structure in which the c-axes of the microcrystals aligned in a certain direction with the mosaic spread less than 1 o , while the a- and b-axes randomly oriented on a plane perpendicular to the c-axes. Interactions between quadrupole moment of 19 F * and 22 Na * with its surroundings electric field gradient were studied by detecting the γ-rays distribution, W(Θ,t). For 1 9F * we found one static interaction. The corresponding electric field gradient was V zz =3.24(19)x10 22 V/m 2 . In the case of 22 Na * we found no evidence of nuclear quadrupole interaction, however, we were able to conclude that |QV 22 | 19 bV/m 2 . Using theoretical calculation Q=0.06 barn, we find that |V zz | 20 V/m 2 . These results indicate that the value efg depend on two factors, the host crystal and the core electrons. The core electrons contribution to the total efg is considerably large

  9. Tank 18-F And 19-F Tank Fill Grout Scale Up Test Summary

    International Nuclear Information System (INIS)

    Stefanko, D.; Langton, C.

    2012-01-01

    High-level waste (HLW) tanks 18-F and 19-F have been isolated from FTF facilities. To complete operational closure the tanks will be filled with grout for the purpose of: (1) physically stabilizing the tanks, (2) limiting/eliminating vertical pathways to residual waste, (3) entombing waste removal equipment, (4) discouraging future intrusion, and (5) providing an alkaline, chemical reducing environment within the closure boundary to control speciation and solubility of select radionuclides. This report documents the results of a four cubic yard bulk fill scale up test on the grout formulation recommended for filling Tanks 18-F and 19-F. Details of the scale up test are provided in a Test Plan. The work was authorized under a Technical Task Request (TTR), HLE-TTR-2011-008, and was performed according to Task Technical and Quality Assurance Plan (TTQAP), SRNL-RP-2011-00587. The bulk fill scale up test described in this report was intended to demonstrate proportioning, mixing, and transportation, of material produced in a full scale ready mix concrete batch plant. In addition, the material produced for the scale up test was characterized with respect to fresh properties, thermal properties, and compressive strength as a function of curing time.

  10. Protein-observed (19)F-NMR for fragment screening, affinity quantification and druggability assessment.

    Science.gov (United States)

    Gee, Clifford T; Arntson, Keith E; Urick, Andrew K; Mishra, Neeraj K; Hawk, Laura M L; Wisniewski, Andrea J; Pomerantz, William C K

    2016-08-01

    NMR spectroscopy can be used to quantify the binding affinity between proteins and low-complexity molecules, termed 'fragments'; this versatile screening approach allows researchers to assess the druggability of new protein targets. Protein-observed (19)F-NMR (PrOF NMR) using (19)F-labeled amino acids generates relatively simple spectra that are able to provide dynamic structural information toward understanding protein folding and function. Changes in these spectra upon the addition of fragment molecules can be observed and quantified. This protocol describes the sequence-selective labeling of three proteins (the first bromodomains of Brd4 and BrdT, and the KIX domain of the CREB-binding protein) using commercially available fluorinated aromatic amino acids and fluorinated precursors as example applications of the method developed by our research group. Fragment-screening approaches are discussed, as well as Kd determination, ligand-efficiency calculations and druggability assessment, i.e., the ability to target these proteins using small-molecule ligands. Experiment times on the order of a few minutes and the simplicity of the NMR spectra obtained make this approach well-suited to the investigation of small- to medium-sized proteins, as well as the screening of multiple proteins in the same experiment.

  11. TANK 18-F AND 19-F TANK FILL GROUT SCALE UP TEST SUMMARY

    Energy Technology Data Exchange (ETDEWEB)

    Stefanko, D.; Langton, C.

    2012-01-03

    High-level waste (HLW) tanks 18-F and 19-F have been isolated from FTF facilities. To complete operational closure the tanks will be filled with grout for the purpose of: (1) physically stabilizing the tanks, (2) limiting/eliminating vertical pathways to residual waste, (3) entombing waste removal equipment, (4) discouraging future intrusion, and (5) providing an alkaline, chemical reducing environment within the closure boundary to control speciation and solubility of select radionuclides. This report documents the results of a four cubic yard bulk fill scale up test on the grout formulation recommended for filling Tanks 18-F and 19-F. Details of the scale up test are provided in a Test Plan. The work was authorized under a Technical Task Request (TTR), HLE-TTR-2011-008, and was performed according to Task Technical and Quality Assurance Plan (TTQAP), SRNL-RP-2011-00587. The bulk fill scale up test described in this report was intended to demonstrate proportioning, mixing, and transportation, of material produced in a full scale ready mix concrete batch plant. In addition, the material produced for the scale up test was characterized with respect to fresh properties, thermal properties, and compressive strength as a function of curing time.

  12. Electron correlation effects on geometries and 19F shieldings of fluorobenzenes

    International Nuclear Information System (INIS)

    Webb, G.A.; Karadakov, P.B.; England, J.A.

    2000-01-01

    In order to include the effects of electron correlation in ab initio molecular orbital calculations it is necessary to go beyond the single determinant Hartree-Fock (HF) level of theory. In the present investigation the influences of both dynamic and non-dynamic correlation effects on the optimised geometries and 19 F nuclear shielding calculations of the twelve fluorobenzenes are reported.The non-dynamic electron correlation effects are represented by complete-active space self-consistent field (CASSCF) calculations. Second- and fourth-order Moller-Plesset (MP2 and MP4) calculations are used to describe the dynamic electron correlation effects. Some density-functional (DFT) results are also reported which do not distinguish between dynamic and non-dynamic electron correlation. Following the correlated geometry optimisations 19 F nuclear shielding calculations were performed using the gauge-included atomic orbitals (GIAO) procedure, these were undertaken with wave functions which include various levels of electron correlation including HF, CASSCF and MP2. For the calculations of the optimised geometries, and some of the nuclear shieldings the 6-13G** basis set s used whereas the locally-dense [6-13G** on C and H and 6-311++G(2d,2p) on F] set is used for some of the shielding calculations. A comparison of the results of HF shielding calculations using other basis sets is included. Comparison of the calculated geometry and shielding results with relevant, reported, experimental data is made. (author)

  13. Evaporation residue excitation function measurement for 19F + 194,198Pt reactions

    International Nuclear Information System (INIS)

    Singh, Varinderjit; Behera, B.R.; Kaur, Maninder

    2012-01-01

    Nuclear dissipation is one of the active fields in the present day nuclear physics research. Experimental signatures for dissipation are observed through large excess in pre-fission neutrons, γ-ray multiplicities from the compound nucleus, giant dipole resonance (GDR) γ-rays, light charged particles and evaporation residues in comparison to standard statistical model, for the heavy-ion induced fusion-fission or fusion-evaporation reactions (ERs). From the analysis of a large set of experimental data, it is well established that there exists a large dissipation at nuclear temperature above 1 MeV. But most of these probes are not sensitive to the dissipation within saddle. The ER cross-section is a probe which is sensitive to dissipation within the saddle point. Hence, the study of ER cross-section can be helpful in estimating the dissipation effects inside the saddle point. Also the other motivation for these measurements is to see the effect of shell closure on dissipation. With this motivation the evaporation cross-sections for 19 F + 194,198 Pt are measured at beam energy of 101 to 137.3 MeV. Of the above systems 19 F + 194 Pt populates 213 Fr (N = 126) shell closed compound nucleus (CN) whereas, other system populate 217 Fr (N = 130) non-shell closed CN

  14. Revisiting the metathesis of 13C-monolabeled ethane

    KAUST Repository

    Maury, Olivier

    2010-12-13

    The metathesis of 13C-monolabeled ethane leads to the parallel occurrence of degenerate and productive reactions, affording the statistical distribution of the various product isotopomers, which can be rationalized in terms of a mechanistic reaction scheme combining both processes. © 2010 American Chemical Society.

  15. 13C-NMR spectra and bonding situation in ketenimines

    International Nuclear Information System (INIS)

    Firl, J.; Runge, W.; Hartmann, W.; Utikal, H.P.

    1975-01-01

    13 C-NMR spectra of a series of substituted ketenimines are reported. The terminal carbon resonances are found at unusual high fields between delta 37 and 78, while the central carbon signals appear around delta 189 - 196. On the basis of these results, the bonding situation in ketenimines has been discussed. (auth.)

  16. 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...

  17. A new, 13C-based material for neutron targets

    International Nuclear Information System (INIS)

    Romanenko, A.I.; Anikeeva, O.B.; Gorbachev, R.V.; Zhmurikov, E.I.; Gubin, K.V.; Logachev, P.V.; Avilov, M.S.; Tsybulya, S.V.; Kryukova, G.N.; Burgina, E.B.; Tecchio, L.

    2005-01-01

    A 13 C-based neutron-target material is investigated using X-ray diffraction, IR absorption and Raman scattering spectroscopies, transmission electron microscopy, and electrical (conductivity, magnetoresistance, and Hall effect) measurements before and after high-power electron irradiation for various lengths of time [ru

  18. TANK 18 AND 19-F TIER 1A EQUIPMENT FILL MOCK UP TEST SUMMARY

    Energy Technology Data Exchange (ETDEWEB)

    Stefanko, D.; Langton, C.

    2011-11-04

    The United States Department of Energy (US DOE) has determined that Tanks 18-F and 19-F have met the F-Tank Farm (FTF) General Closure Plan Requirements and are ready to be permanently closed. The high-level waste (HLW) tanks have been isolated from FTF facilities. To complete operational closure they will be filled with grout for the purpose of: (1) physically stabilizing the tanks, (2) limiting/eliminating vertical pathways to residual waste, (3) discouraging future intrusion, and (4) providing an alkaline, chemical reducing environment within the closure boundary to control speciation and solubility of select radionuclides. Bulk waste removal and heel removal equipment remain in Tanks 18-F and 19-F. This equipment includes the Advance Design Mixer Pump (ADMP), transfer pumps, transfer jets, standard slurry mixer pumps, equipment-support masts, sampling masts, dip tube assemblies and robotic crawlers. The present Tank 18 and 19-F closure strategy is to grout the equipment in place and eliminate vertical pathways by filling voids in the equipment to vertical fast pathways and water infiltration. The mock-up tests described in this report were intended to address placement issues identified for grouting the equipment that will be left in Tank 18-F and Tank 19-F. The Tank 18-F and 19-F closure strategy document states that one of the Performance Assessment (PA) requirements for a closed tank is that equipment remaining in the tank be filled to the extent practical and that vertical flow paths 1 inch and larger be grouted. The specific objectives of the Tier 1A equipment grout mock-up testing include: (1) Identifying the most limiting equipment configurations with respect to internal void space filling; (2) Specifying and constructing initial test geometries and forms that represent scaled boundary conditions; (3) Identifying a target grout rheology for evaluation in the scaled mock-up configurations; (4) Scaling-up production of a grout mix with the target rheology

  19. 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.

  20. 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)

  1. 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)

  2. 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)

  3. 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##

  4. 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)

  5. Tanks 18 And 19-F Structural Flowable Grout Fill Material Evaluation And Recommendations

    International Nuclear Information System (INIS)

    Langton, C. A.; Stefanko, D. B.

    2013-01-01

    Cementitious grout will be used to close Tanks 18-F and 19-F. The functions of the grout are to: 1) physically stabilize the final landfill by filling the empty volume in the tanks with a non-compressible material; 2) provide a barrier for inadvertent intrusion into the tank; 3) reduce contaminant mobility by a) limiting the hydraulic conductivity of the closed tank and b) reducing contact between the residual waste and infiltrating water; and 4) providing an alkaline, chemically reducing environment in the closed tank to control speciation and solubility of selected radionuclides. The objective of this work was to identify a single (all-in-one) grout to stabilize and isolate the residual radionuclides in the tank, provide structural stability of the closed tank and serve as an inadvertent intruder barrier. This work was requested by V. A. Chander, High Level Waste (HLW) Tank Engineering, in HLW-TTR-2011-008. The complete task scope is provided in the Task Technical and QA Plan, SRNL-RP-2011-00587 Revision 0. The specific objectives of this task were to: 1) Identify new admixtures and dosages for formulating a zero bleed flowable tank fill material selected by HLW Tank Closure Project personnel based on earlier tank fill studies performed in 2007. The chemical admixtures used for adjusting the flow properties needed to be updated because the original admixture products are no longer available. Also, the sources of cement and fly ash have changed, and Portland cements currently available contain up to 5 wt. % limestone (calcium carbonate). 2) Prepare and evaluate the placement, compressive strength, and thermal properties of the selected formulation with new admixture dosages. 3) Identify opportunities for improving the mix selected by HLW Closure Project personnel and prepare and evaluate two potentially improved zero bleed flowable fill design concepts; one based on the reactor fill grout and the other based on a shrinkage compensating flowable fill mix design. 4

  6. Metabolism of 5-fluorouracil in human liver: an in vivo 19F NMR study

    International Nuclear Information System (INIS)

    Mohankrishnan, P.; Sprigg, J.; Cardwell, D.; Komoroski, R.A.; Hutchins, L.; Nauke, S.; Williamson, M.R.; Jagannathan, N.R.

    1999-01-01

    In vivo fluorine-19 nuclear magnetic resonance ( 19 F NMR) spectroscopy was used to study the metabolism and pharmacokinetics of 5-fluorouracil (5-FU) in human liver. Nine patients received 5-FU, and additional chemotherapeutic agents (methotrexate, leucovorin, or levamisole) either prophylactically after breast cancer surgery or for colorectal cancer. The time constant for the disappearance of 5-FU from the liver in vivo varied from 5 to 17 min, while the time constant for the appearance of α-fluoro-β-alanine (the major catabolite of 5 FU) varied from 7 to 86 min. The modulators of 5-FU metabolism did not appear to affect the time constant for the disappearance of 5-FU from the liver or for the appearance of α-fluoro-β-alanine. Results obtained indicate that the pharmacokinetics of 5-FU and α-fluoro-β-alanine may vary substantially at different times in a given individual. (author)

  7. Tanks 18 And 19-F Structural Flowable Grout Fill Material Evaluation And Recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C. A.; Stefanko, D. B.

    2013-04-23

    Cementitious grout will be used to close Tanks 18-F and 19-F. The functions of the grout are to: 1) physically stabilize the final landfill by filling the empty volume in the tanks with a non-compressible material; 2) provide a barrier for inadvertent intrusion into the tank; 3) reduce contaminant mobility by a) limiting the hydraulic conductivity of the closed tank and b) reducing contact between the residual waste and infiltrating water; and 4) providing an alkaline, chemically reducing environment in the closed tank to control speciation and solubility of selected radionuclides. The objective of this work was to identify a single (all-in-one) grout to stabilize and isolate the residual radionuclides in the tank, provide structural stability of the closed tank and serve as an inadvertent intruder barrier. This work was requested by V. A. Chander, High Level Waste (HLW) Tank Engineering, in HLW-TTR-2011-008. The complete task scope is provided in the Task Technical and QA Plan, SRNL-RP-2011-00587 Revision 0. The specific objectives of this task were to: 1) Identify new admixtures and dosages for formulating a zero bleed flowable tank fill material selected by HLW Tank Closure Project personnel based on earlier tank fill studies performed in 2007. The chemical admixtures used for adjusting the flow properties needed to be updated because the original admixture products are no longer available. Also, the sources of cement and fly ash have changed, and Portland cements currently available contain up to 5 wt. % limestone (calcium carbonate). 2) Prepare and evaluate the placement, compressive strength, and thermal properties of the selected formulation with new admixture dosages. 3) Identify opportunities for improving the mix selected by HLW Closure Project personnel and prepare and evaluate two potentially improved zero bleed flowable fill design concepts; one based on the reactor fill grout and the other based on a shrinkage compensating flowable fill mix design. 4

  8. Measurement of 19F nucleus interaction at 4 GeV/c per nucleon

    International Nuclear Information System (INIS)

    Golovin, V.M.; Golutvin, I.A.; Dolya, S.N.

    1986-01-01

    The cross sections of 19 F nucleus interaction with the nuclei of different elements at 4 GeV/c x nucleon momentum in reactions are measured. In the finite state of these reactions the fragment with charge Z≤8 is formed. The experiment apparatus comprises a transmission detector where the nuclei trajectory at the target input has been measured with proportional chambers whereas the nuclear charge before and after the target has been measured by Cherenkov counters. Experimental data obtained with accuracy - 2% are presented for carbon, aluminium, copper, indium, tungsten, bismuth and uranium targets. The dependence of cross sections on atomic number of the target coincides except of cross section of interaction with heavy targets

  9. 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)

  10. Deconvolution of the tree ring based delta13C record

    International Nuclear Information System (INIS)

    Peng, T.; Broecker, W.S.; Freyer, H.D.; Trumbore, S.

    1983-01-01

    We assumed that the tree-ring based 13 C/ 12 C record constructed by Freyer and Belacy (1983) to be representative of the fossil fuel and forest-soil induced 13 C/ 12 C change for atmospheric CO 2 . Through the use of a modification of the Oeschger et al. ocean model, we have computed the contribution of the combustion of coal, oil, and natural gas to this observed 13 C/ 12 C change. A large residual remains when the tree-ring-based record is corrected for the contribution of fossil fuel CO 2 . A deconvolution was performed on this residual to determine the time history and magnitude of the forest-soil reservoir changes over the past 150 years. Several important conclusions were reached. (1) The magnitude of the integrated CO 2 input from these sources was about 1.6 times that from fossil fuels. (2) The forest-soil contribution reached a broad maximum centered at about 1900. (3) Over the 2 decade period covered by the Mauna Loa atmospheric CO 2 content record, the input from forests and soils was about 30% that from fossil fuels. (4) The 13 C/ 12 C trend over the last 20 years was dominated by the input of fossil fuel CO 2 . (5) The forest-soil release did not contribute significantly to the secular increase in atmospheric CO 2 observed over the last 20 years. (6) The pre-1850 atmospheric p2 values must have been in the range 245 to 270 x 10 -6 atmospheres

  11. 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...

  12. EDGE2D Simulations of JET 13C Migration Experiments

    International Nuclear Information System (INIS)

    Strachan, J.D.; Coad, J.P.; Corrigan, G.; Matthews, G.F.; Spence, J.

    2004-01-01

    Material migration has received renewed interest due to tritium retention associated with carbon transport to remote vessel locations. Those results influence the desirability of carbon usage on ITER. Subsequently, additional experiments have been performed, including tracer experiments attempting to identify material migration from specific locations. In this paper, EDGE2D models a well-diagnosed JET 13 C tracer migration experiment. The role of SOL flows upon the migration patterns is identified

  13. Thermonuclear 19F(p, {{\\boldsymbol{\\alpha }}}_{0})16O reaction rate

    Science.gov (United States)

    He, Jian-Jun; Lombardo, Ivano; Dell'Aquila, Daniele; Xu, Yi; Zhang, Li-Yong; Liu, Wei-Ping

    2018-01-01

    The thermonuclear 19F(p, {{{α }}}0)16O reaction rate in the temperature region 0.007-10 GK has been derived by re-evaluating the available experimental data, together with the low-energy theoretical R-matrix extrapolations. Our new rate deviates by up to about 30% compared to the previous results, although all rates are consistent within the uncertainties. At very low temperature (e.g. 0.01 GK) our reaction rate is about 20% lower than the most recently published rate, because of a difference in the low energy extrapolated S-factor and a more accurate estimate of the reduced mass used in the calculation of the reaction rate. At temperatures above ˜1 GK, our rate is lower, for instance, by about 20% around 1.75 GK, because we have re-evaluated the previous data (Isoya et al., Nucl. Phys. 7, 116 (1958)) in a meticulous way. The present interpretation is supported by the direct experimental data. The uncertainties of the present evaluated rate are estimated to be about 20% in the temperature region below 0.2 GK, and are mainly caused by the lack of low-energy experimental data and the large uncertainties in the existing data. Asymptotic giant branch (AGB) stars evolve at temperatures below 0.2 GK, where the 19F(p, {{α }})16O reaction may play a very important role. However, the current accuracy of the reaction rate is insufficient to help to describe, in a careful way, the fluorine over-abundances observed in AGB stars. Precise cross section (or S factor) data in the low energy region are therefore needed for astrophysical nucleosynthesis studies. Supported by National Natural Science Foundation of China (11490562, 11490560, 11675229) and National Key Research and Development Program of China (2016YFA0400503)

  14. 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

  15. 19F NMR studies of 5-fluorouracil-substituted Escherichia coli transfer RNAs: solution structure and codon-anticodon interaction

    International Nuclear Information System (INIS)

    Gollnick, P.D.

    1986-01-01

    19 F NMR was used to study E. coli tRNA 1 /sup Val/, tRNA/sub f//sup Met/, and tRNA/sub m//Met/, in which 5-fluorouracil (FUra) has replaced uracil and uracil-derived minor bases. 19 F NMR spectra of these tRNAs resolve resonances from nearly all the incorporated FUra residues. Each of the three tRNAs can be resolved into two isoaccepting species, termed forms A and B, whose 19 F spectra differ in the shift of one 19 F peak from ca. 4.5 ppm in form B, upfield to -15 ppm in form A. Because the two isoacceptors of each tRNA differ only at one position, the peaks at 4.5 ppm in the spectra of (FUra)tRNA 1 /sup Val/ and (FUra)tRNA/sub m//sup Met/; are assigned to FUra 17 and Fura 20 respectively. Bisulfate modification and pH dependence indicate that 19 F signals in the central region of the spectrum of (FUra)tRNA 1 /sup Val/ correspond to fluorouracils in non-base-paired regions. Photoreaction with psoralen indicates upfield 19 F signals arise from residues in helical environments. Removal of magnesium or addition of NaCl produces major, reversible changes in the 19 F spectrum of fluorinated tRNAs. Studies of manganese and spermine binding to (FUra)tRNA 1 /sup Val/ allow localization of several resonances in the 18 F spectrum to regions near putative binding sites for these ions. Binding of the codon G/sub p/U/sub p/A causes an upfield shift of a 19 F resonance at 3.9 ppm in the spectrum of (FUra)tRNA 1 /sup Val/. G/sub p/U/sub p/A/sub p/A, which is complementary to the anticodon and 5'-adjacent FUra 33, shifts an additional 19 F peak at 4.5 ppm. 1 H NMR and RNase H digestion studies show that the oligonucleotides bind to the anticodon

  16. Direct Comparison of 19F qNMR and 1H qNMR by Characterizing Atorvastatin Calcium Content

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2016-01-01

    Full Text Available Quantitative nuclear magnetic resonance (qNMR is a powerful tool in measuring drug content because of its high speed, sensitivity, and precision. Most of the reports were based on proton qNMR (1H qNMR and only a few fluorine qNMR (19F qNMR were reported. No research has been conducted to directly compare the advantage and disadvantage between these two methods. In the present study, both 19F and 1H qNMR were performed to characterize the content of atorvastatin calcium with the same internal standard. Linearity, precision, and results from two methods were compared. Results showed that 19F qNMR has similar precision and sensitivity to 1H qNMR. Both methods generate similar results compared to mass balance method. Major advantage from 19F qNMR is that the analyte signal is with less or no interference from impurities. 19F qNMR is an excellent approach to quantify fluorine-containing analytes.

  17. 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)

  18. Galactose oxidation using 13C in healthy and galactosemic children

    Directory of Open Access Journals (Sweden)

    D.R. Resende-Campanholi

    2015-03-01

    Full Text Available Galactosemia is an inborn error of galactose metabolism that occurs mainly as the outcome of galactose-1-phosphate uridyltransferase (GALT deficiency. The ability to assess galactose oxidation following administration of a galactose-labeled isotope (1-13C-galactose allows the determination of galactose metabolism in a practical manner. We aimed to assess the level of galactose oxidation in both healthy and galactosemic Brazilian children. Twenty-one healthy children and seven children with galactosemia ranging from 1 to 7 years of age were studied. A breath test was used to quantitate 13CO2 enrichment in exhaled air before and at 30, 60, and 120 min after the oral administration of 7 mg/kg of an aqueous solution of 1-13C-galactose to all children. The molar ratios of 13CO2 and 12CO2 were quantified by the mass/charge ratio (m/z of stable isotopes in each air sample by gas-isotope-ratio mass spectrometry. In sick children, the cumulative percentage of 13C from labeled galactose (CUMPCD in the exhaled air ranged from 0.03% at 30 min to 1.67% at 120 min. In contrast, healthy subjects showed a much broader range in CUMPCD, with values from 0.4% at 30 min to 5.58% at 120 min. The study found a significant difference in galactose oxidation between children with and without galactosemia, demonstrating that the breath test is useful in discriminating children with GALT deficiencies.

  19. Compartmentation of glycogen metabolism revealed from 13C isotopologue distributions

    Directory of Open Access Journals (Sweden)

    Marin de Mas Igor

    2011-10-01

    Full Text Available Abstract Background Stable isotope tracers are used to assess metabolic flux profiles in living cells. The existing methods of measurement average out the isotopic isomer distribution in metabolites throughout the cell, whereas the knowledge of compartmental organization of analyzed pathways is crucial for the evaluation of true fluxes. That is why we accepted a challenge to create a software tool that allows deciphering the compartmentation of metabolites based on the analysis of average isotopic isomer distribution. Results The software Isodyn, which simulates the dynamics of isotopic isomer distribution in central metabolic pathways, was supplemented by algorithms facilitating the transition between various analyzed metabolic schemes, and by the tools for model discrimination. It simulated 13C isotope distributions in glucose, lactate, glutamate and glycogen, measured by mass spectrometry after incubation of hepatocytes in the presence of only labeled glucose or glucose and lactate together (with label either in glucose or lactate. The simulations assumed either a single intracellular hexose phosphate pool, or also channeling of hexose phosphates resulting in a different isotopic composition of glycogen. Model discrimination test was applied to check the consistency of both models with experimental data. Metabolic flux profiles, evaluated with the accepted model that assumes channeling, revealed the range of changes in metabolic fluxes in liver cells. Conclusions The analysis of compartmentation of metabolic networks based on the measured 13C distribution was included in Isodyn as a routine procedure. The advantage of this implementation is that, being a part of evaluation of metabolic fluxes, it does not require additional experiments to study metabolic compartmentation. The analysis of experimental data revealed that the distribution of measured 13C-labeled glucose metabolites is inconsistent with the idea of perfect mixing of hexose

  20. Tanks 18 And 19-F Structural Flowable Grout Fill Material Evaluation And Recommendations

    International Nuclear Information System (INIS)

    Stefanko, D.; Langton, C.

    2011-01-01

    Cementitious grout will be used to close Tanks 18-F and 19-F. The functions of the grout are to: (1) physically stabilize the final landfill by filling the empty volume in the tanks with a non compressible material; (2) provide a barrier for inadvertent intrusion into the tank; (3) reduce contaminant mobility by (a) limiting the hydraulic conductivity of the closed tank and (b) reducing contact between the residual waste and infiltrating water; and (4) providing an alkaline, chemically reducing environment in the closed tank to control speciation and solubility of selected radionuclides. The objective of this work was to identify a single (all-in-one) grout to stabilize and isolate the residual radionuclides in the tank, provide structural stability of the closed tank and serve as an inadvertent intruder barrier. This work was requested by V. A. Chander, High Level Waste (HLW) Tank Engineering, in HLW-TTR-2011-008. The complete task scope is provided in the Task Technical and QA Plan, SRNL-RP-2011-00587 Revision 0. The specific objectives of this task were to: (1) Identify new admixtures and dosages for formulating a zero bleed flowable tank fill material selected by HLW Tank Closure Project personnel based on earlier tank fill studies performed in 2007. The chemical admixtures used for adjusting the flow properties needed to be updated because the original admixture products are no longer available. Also, the sources of cement and fly ash have changed, and Portland cements currently available contain up to 5 wt. % limestone (calcium carbonate). (2) Prepare and evaluate the placement, compressive strength, and thermal properties of the selected formulation with new admixture dosages. (3) Identify opportunities for improving the mix selected by HLW Closure Project personnel and prepare and evaluate two potentially improved zero bleed flowable fill design concepts; one based on the reactor fill grout and the other based on a shrinkage compensating flowable fill mix

  1. TANKS 18 AND 19-F STRUCTURAL FLOWABLE GROUT FILL MATERIAL EVALUATION AND RECOMMENDATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Stefanko, D.; Langton, C.

    2011-11-01

    Cementitious grout will be used to close Tanks 18-F and 19-F. The functions of the grout are to: (1) physically stabilize the final landfill by filling the empty volume in the tanks with a non compressible material; (2) provide a barrier for inadvertent intrusion into the tank; (3) reduce contaminant mobility by (a) limiting the hydraulic conductivity of the closed tank and (b) reducing contact between the residual waste and infiltrating water; and (4) providing an alkaline, chemically reducing environment in the closed tank to control speciation and solubility of selected radionuclides. The objective of this work was to identify a single (all-in-one) grout to stabilize and isolate the residual radionuclides in the tank, provide structural stability of the closed tank and serve as an inadvertent intruder barrier. This work was requested by V. A. Chander, High Level Waste (HLW) Tank Engineering, in HLW-TTR-2011-008. The complete task scope is provided in the Task Technical and QA Plan, SRNL-RP-2011-00587 Revision 0. The specific objectives of this task were to: (1) Identify new admixtures and dosages for formulating a zero bleed flowable tank fill material selected by HLW Tank Closure Project personnel based on earlier tank fill studies performed in 2007. The chemical admixtures used for adjusting the flow properties needed to be updated because the original admixture products are no longer available. Also, the sources of cement and fly ash have changed, and Portland cements currently available contain up to 5 wt. % limestone (calcium carbonate). (2) Prepare and evaluate the placement, compressive strength, and thermal properties of the selected formulation with new admixture dosages. (3) Identify opportunities for improving the mix selected by HLW Closure Project personnel and prepare and evaluate two potentially improved zero bleed flowable fill design concepts; one based on the reactor fill grout and the other based on a shrinkage compensating flowable fill mix

  2. M1 suppression in pion photoproduction on 13C

    International Nuclear Information System (INIS)

    Tiator, L.

    1983-02-01

    Recently measured anomalously low cross sections for 13 C(γ,π - ) 13 N at low energy and theta sub(π)sup(lab) = 90 degrees have been analyzed in a DWIA calculation. It has been found that the EO contribution alone is able to explain the data, so that the MI cross section is expected to vanish. Using constraints from recent magnetic electron scattering, an explanation is possible by assuming a significantly lower reduced density matrix element for spin-flip isovector transitions with angular momentum L = 2 than predicted by Cohen-Kurath

  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. /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.

  5. 19F-MRI of stomach and intestine using 50% FTPA emulsion under 2T MRI system

    International Nuclear Information System (INIS)

    Shimizu, Masahiro; Kobayashi, Teturou; Mishima, Hideyuki

    1991-01-01

    1 H-MRI is of clinical value in many lesions, but imaging of gastrointestinal lesions is still difficult by 1 H-MRI. To overcome this weak point of 1 H-MRI, rabbit stomachs were examined by 19 F-MRI using 50% FTPA emulsion. We also examined the stability of 50% FTPA emulsion in the stomach and its absorption from the gastrointestinal tract. We found that 50% FTPA emulsion was very stable at pH 1.5, and only a very small amount was absorbed. A rabbit (weighing 2 kg) was anesthetized, and 100 ml of 50% FTPA emulsion was infused into the stomach by catheter. 19 F-MRI was performed in this rabbit using a 2 T superconducting MRI system designed for human use, and clear pictures of the stomach were obtained. From our results we conclude that 19 F-MRI of the stomach using 50% FTPA emulsion is of practical value. (author)

  6. Nuclear reactions in AGB nucleosynthesis: the 19F(α, p22Ne at energies of astrophysical relevance

    Directory of Open Access Journals (Sweden)

    D’Agata G.

    2017-01-01

    Full Text Available The abundance of 19F in the universe is strictly related to standard and extra-mixing processes taking place inside AGB-stars, that are considered to be the most important sites for its production. Nevertheless the way in which it is destroyed is far from being well understood. For this reason we studied the 19F(α,p22Ne reaction, that is supposed to be the main destruction channel in the Helium-rich part of the star. In this experiment, the reaction has been studied in the energy range of relevance for astrophysics (0÷1 MeV via the Trojan Horse Method (THM, using the three-body reaction 6Li(19F,p22Ned.

  7. Electronic stopping powers for fluorine ions in {sup 19}F{sup +}-implanted AgGaS{sub 2} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiangdong; Xia Yueyuan; Lu Qingming; Li Feng; Huang Boda

    2004-01-15

    Electronic stopping powers for 80-350 keV {sup 19}F ions in AgGaS{sub 2} were obtained by range measurement. Depth profiles of {sup 19}F in AgGaS{sub 2} were measured by using the {sup 19}F(p,{alpha}{gamma}){sup 16}O resonant nuclear reaction at E{sub R}=872.1 keV. A proper convolution calculation method was used to extract the true distribution of fluorine from the experimental excitation yield curves. The electronic stopping powers were derived through fitting the projected range distributions, simulated by using the TRIM/XLL code, to the experimentally measured range distributions. The electronic stopping cross sections were compared with those obtained from Monte Carlo simulation codes.

  8. Electronic stopping powers for fluorine ions in 19F+-implanted AgGaS2 crystal

    International Nuclear Information System (INIS)

    Liu Xiangdong; Xia Yueyuan; Lu Qingming; Li Feng; Huang Boda

    2004-01-01

    Electronic stopping powers for 80-350 keV 19 F ions in AgGaS 2 were obtained by range measurement. Depth profiles of 19 F in AgGaS 2 were measured by using the 19 F(p,αγ) 16 O resonant nuclear reaction at E R =872.1 keV. A proper convolution calculation method was used to extract the true distribution of fluorine from the experimental excitation yield curves. The electronic stopping powers were derived through fitting the projected range distributions, simulated by using the TRIM/XLL code, to the experimentally measured range distributions. The electronic stopping cross sections were compared with those obtained from Monte Carlo simulation codes

  9. 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

  10. 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

  11. (19)F-heptuloses as tools for the non-invasive imaging of GLUT2-expressing cells

    DEFF Research Database (Denmark)

    Malaisse, Willy J; Zhang, Ying; Louchami, Karim

    2012-01-01

    Suitable analogs of d-mannoheptulose are currently considered as possible tools for the non-invasive imaging of pancreatic islet insulin-producing cells. Here, we examined whether (19)F-heptuloses could be used for non-invasive imaging of GLUT2-expressing cells. After 20 min incubation, the uptake......-mannoheptulose in inhibiting insulin release. The 1-deoxy-1-fluoro-d-mannoheptulose and 3-deoxy-3-fluoro-d-mannoheptulose only marginally affected INS-1 cell viability. These findings are compatible with the view that selected (19)F-heptuloses may represent suitable tools for the non-invasive imaging of hepatocytes...

  12. Measurement of the 19F(n,2n)18F cross section from 18 to 27 MeV

    International Nuclear Information System (INIS)

    Hartmann, C.L.; DeLuca, P.M. Jr.

    1990-01-01

    the 19 F(n,2n) 18 F cross section was measured at neutron energies of 18, 21, 23, and 27 MeV. Nearly monoenergetic neutrons bombarded teflon (CF 2 ), Zr, and Au samples. 19 F(n,2n) 18 F cross section values were determined relative to nat Zr(n,xn) 89 Zr and 197 Au(n,2n) 196 Au from measurements of the 18 F, 89 Zr, and 196 Au activities. Our results are in agreement with previous measurements below 20 MeV and extend the usefulness of this reaction to 27 MeV. 22 refs., 1 fig., 2 tabs

  13. Characterization and validation of noninvasive oxygen tension measurements in human glioma xenografts by 19F-MR relaxometry

    International Nuclear Information System (INIS)

    Sanden, Boudewijn P.J. van der; Heerschap, Arend; Simonetti, Arjan W.; Rijken, Paul F.J.W.; Peters, Hans P.W.; Stbeen, Georg; Kogel, Albert J. van der

    1999-01-01

    Purpose: The aim of this study was to characterize and to validate noninvasive 19 F-magnetic resonance relaxometry for the measurement of oxygen tensions in human glioma xenografts in nude mice. The following three questions were addressed: 1. When perfluorocarbon compounds (PFCs) are administrated intravenously, which tumor regions are assessed by 19 F-MR relaxometry? 2. Are oxygen tension as detected by 19 F-MR relaxometry (pO 2/relaxo ) comparable to Eppendorf O 2 -electrode measurements (pO 2/electrode )? 3. Can 19 F-MR relaxometry be used to detect oxygen tension changes in tumor tissue during carbogen breathing? Methods and Materials: Slice-selective 19 F-MR relaxometry was carried out with perfluoro-15-crown-5-ether as oxygen sensor. The PFC was injected i.v. 3 days before the 19 F-MR experiments. Two datasets were acquired before and two after the start of carbogen breathing. The distribution of PFCs and necrotic areas were analyzed in 19 F-Spin Echo (SE) density MR images and T 2 -weighted 1 H-SE MR images, respectively. One day after the MR investigations, oxygen tensions were measured by oxygen electrodes in the same slice along two perpendicular tracks. These measurements were followed by (immuno)histochemical analysis of the 2D distribution of perfused microvessels, hypoxic cells, necrotic areas, and macrophages. Results: The PFCs mainly became sequestered in perfused regions at the tumor periphery; thus, 19 F-MR relaxometry probed mean oxygen tensions in these regions throughout the selected MR slice. In perfused regions of the tumor, mean pO 2/relaxo values were comparable to mean pO 2/electrode values, and varied from 0.03 to 9 mmHg. Median pO 2/electrode values of both tracks were lower than mean pO 2/relaxo values, because low pO 2/electrode values that originate from hypoxic and necrotic areas were also included in calculations of median pO 2/electrode values. After 8-min carbogen breathing, the average pO 2/relaxo increase was 3.3 ± 0.8 (SEM

  14. Pre-scission 4He multiplicity in the 19F+197Au reaction

    International Nuclear Information System (INIS)

    Ikezoe, H.; Shikazono, N.; Nagame, Y.; Sugiyama, Y.; Tomita, Y.; Ideno, K.; Iwamoto, A.; Ohtsuki, T.

    1990-01-01

    Pre- and post-scission 4 He particle multiplicities for the 19 F+ 197 Au reaction in the excitation energy range of 43 to 90 MeV have been measured in coincidence with fission fragments. The coincident 4 He particles measured at backward angles are accounted for by evaporation from a compound nucleus and fission fragments. The most probable center-of-mass energy of the 4 He particles measured at backward angles is shifted towards lower energies by ∼2 MeV compared to a statistical model calculation performed by assuming 4 He emission from a spherical compound nucleus. The observed pre-scission 4 He multiplicity as a function of excitation energy is compared to a set of statistical-model calculations which also included the delayed onset of fission. The comparison shows that the observed energy dependence of the pre-scission 4 He multiplicity is reproduced by the calculation without taking into account the delayed onset of fission if the reduced emission barrier for 4 He is assumed in the calculation. The emission mechanism of the pre-scission 4 He is discussed

  15. 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

  16. 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.

  17. HSQC-1,n-ADEQUATE: a new approach to long-range 13C-13C correlation by covariance processing.

    Science.gov (United States)

    Martin, Gary E; Hilton, Bruce D; Willcott, M Robert; Blinov, Kirill A

    2011-10-01

    Long-range, two-dimensional heteronuclear shift correlation NMR methods play a pivotal role in the assembly of novel molecular structures. The well-established GHMBC method is a high-sensitivity mainstay technique, affording connectivity information via (n)J(CH) coupling pathways. Unfortunately, there is no simple way of determining the value of n and hence no way of differentiating two-bond from three- and occasionally four-bond correlations. Three-bond correlations, however, generally predominate. Recent work has shown that the unsymmetrical indirect covariance or generalized indirect covariance processing of multiplicity edited GHSQC and 1,1-ADEQUATE spectra provides high-sensitivity access to a (13)C-(13) C connectivity map in the form of an HSQC-1,1-ADEQUATE spectrum. Covariance processing of these data allows the 1,1-ADEQUATE connectivity information to be exploited with the inherent sensitivity of the GHSQC spectrum rather than the intrinsically lower sensitivity of the 1,1-ADEQUATE spectrum itself. Data acquisition times and/or sample size can be substantially reduced when covariance processing is to be employed. In an extension of that work, 1,n-ADEQUATE spectra can likewise be subjected to covariance processing to afford high-sensitivity access to the equivalent of (4)J(CH) GHMBC connectivity information. The method is illustrated using strychnine as a model compound. Copyright © 2011 John Wiley & Sons, Ltd.

  18. {sup 13} C-NMR of mesquite gum

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Cristina T; Garcia, Rosangela B [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Macromoleculas

    1992-12-31

    Mesquite and guar gums are galactomannans extracted from the seeds of Proposis Juliflora and Cyamopsis tetragonolobus, respectively. An experimental sample of mesquite gum and a commercial sample of guar gum were partially depolymerized by ultrasonic radiation and the produce analysed by high resolution {sup 13} C-NMR spectroscopy. The different carbon lines were resolved and their assignments were done as those reported in the literature. The galactose to mannose ratios (G/M) were estimated from the relative peak areas of the C-1 lines as G/M=61 for mesquite and G/M=0.54 for guar gum. The next nearest-neighbour probabilities (diad frequencies) of the D-galactosyl substitution to the D-mannose backbone were evaluated by integrating C-4 mannose splitted peaks. (author) 9 refs., 2 figs., 2 tabs.

  19. Isotopic separation of 13C by selective photodissociation of formaldehyde

    International Nuclear Information System (INIS)

    Mussillon, T.

    1998-01-01

    The aim of this work is to study the feasibility of the 13 C isotopic separation by UV laser spectroscopy. The spectra of H 2 12 CO and H 2 13 CO have been recorded by a Fourier transform spectrometer between 28000 and 34000 cm -1 . From these data has been carried out a systematic study of some lines by laser spectroscopy. The selectivity measurements have been compared with the obtained enrichment factors. Thus has been revealed in a quantitative way, the importance of the isotopic re-mixture phenomena and of the selectivity loss. The best enrichment factor has been measured at 29935,56 cm -1 (band: (2,14,1)). A final percentage of 42,1 % has been obtained in a reproducible way for 13 C. The evolution of the enrichment factor has been characterized for a pressure range between 4,4 and 43 mbar. Above the radical dissociation threshold, it has not be possible to show a positive effect of NO on the enrichment factor. This negative result has been explained by a detailed kinetic study of the radical reactions (available literature). This experimental study has been completed by a bibliographic synthesis for understanding the formaldehyde photochemistry. All the processes able to influence the performance of this isotopic separation process have been gathered in this work in an exhaustive way. The radical dissociation threshold of H 2 13 CO have been calculated from molecular constants of the literature and from known thermodynamic data for H 2 12 CO. (O.M.)

  20. Detection of site-specific binding and co-binding of ligands to macromolecules using 19F NMR

    International Nuclear Information System (INIS)

    Jenkins, B.G.

    1991-01-01

    Study of ligand-macromolecular interactions by 19 F nuclear magnetic resonance (NMR) spectroscopy affords many opportunities for obtaining molecular biochemical and pharmaceutical information. This is due to the absence of a background fluorine signal, as well as the relatively high sensitivity of 19 F NMR. Use of fluorine-labeled ligands enables one to probe not only binding and co-binding phenomena to macromolecules, but also can provide data on binding constants, stoichiometries, kinetics, and conformational properties of these complexes. Under conditions of slow exchange and macromolecule-induced chemical shifts, multiple 19 F NMR resonances can be observed for free and bound ligands. These shifted resonances are a direct correlate of the concentration of ligand bound in a specific state rather than the global concentrations of bound or free ligand which are usually determined using other techniques such as absorption spectroscopy or equilibrium dialysis. Examples of these interactions are demonstrated both from the literature and from interactions of 5-fluorotryptophan, 5-fluorosalicylic acid, flurbiprofen, and sulindac sulfide with human serum albumin. Other applications of 19 F NMR to study of these interactions in vivo, as well for receptor binding and metabolic tracing of fluorinated drugs and proteins are discussed

  1. The astrophysical S-factor of the direct 18O(p, γ)19F capture by the ANC method

    Science.gov (United States)

    Burjan, V.; Hons, Z.; Kroha, V.; Mrázek, J.; Piskoř, Š.; Mukhamedzhanov, A. M.; Trache, L.; Tribble, R. E.; La Cognata, M.; Lamia, L.; Pizzone, G. R.; Romano, S.; Spitaleri, C.; Tumino, A.

    2018-01-01

    We attempted to determine the astrophysical S-factor of the direct part of the 18O(p, γ)19F capture by the indirect method of asymptotic normalization coefficients (ANC). We measured the differential cross section of the transfer reaction 18O(3He, d)19F at a 3He energy of 24.6 MeV. The measurement was realized on the cyclotron of the NPI in Řež, Czech Republic, with the gas target consisting of the high purity 18O (99.9 %). The reaction products were measured by eight ΔE-E telescopes composed from thin and thick silicon surface-barrier detectors. The parameters of the optical model for the input channel were deduced by means of the code ECIS and the analysis of transfer reactions to 12 levels of the 19F nucleus up to 8.014 MeV was made by the code FRESCO. The deduced ANCs were then used to specify the direct contribution to the 18O(p, γ)19F capture process and were compared with the mutually different results of two works.

  2. Synthesis of Intrinsically Disordered Fluorinated Peptides for Modular Design of High-Signal 19 F MRI Agents.

    Science.gov (United States)

    Kirberger, Steven E; Maltseva, Sofia D; Manulik, Joseph C; Einstein, Samuel A; Weegman, Bradley P; Garwood, Michael; Pomerantz, William C K

    2017-06-01

    19 F MRI is valuable for in vivo imaging due to the only trace amounts of fluorine in biological systems. Because of the low sensitivity of MRI however, designing new fluorochemicals remains a significant challenge for achieving sufficient 19 F signal. Here, we describe a new class of high-signal, water-soluble fluorochemicals as 19 F MRI imaging agents. A polyamide backbone is used for tuning the proteolytic stability to avoid retention within the body, which is a limitation of current state-of-the-art perfluorochemicals. We show that unstructured peptides containing alternating N-ϵ-trifluoroacetyllysine and lysine provide a degenerate 19 F NMR signal. 19 F MRI phantom images provide sufficient contrast at micromolar concentrations, showing promise for eventual clinical applications. Finally, the degenerate high signal characteristics were retained when conjugated to a large protein, indicating potential for in vivo targeting applications, including molecular imaging and cell tracking. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Optimization of localized 19F magnetic resonance spectroscopy for the detection of fluorinated drugs in the human liver.

    NARCIS (Netherlands)

    Klomp, D.W.J.; Laarhoven, H.W.M. van; Kentgens, A.P.M.; Heerschap, A.

    2003-01-01

    Fluorine MR spectroscopy ((19)F MRS) is an indispensable tool for assessing the pharmacokinetics of fluorinated drugs. Since the metabolism of 5-fluorouracil (5FU), a frequently used cytotoxic drug, is expected to be different in normal liver and in tumor tissue, spatial localization is required for

  4. Optimization of localized 19F magnetic resonance spectroscopy for the detection of fluorinated drugs in the human liver

    NARCIS (Netherlands)

    Klomp, Dennis W. J.; van Laarhoven, Hanneke W. M.; Kentgens, Arno P. M.; Heerschap, Arend

    2003-01-01

    Fluorine MR spectroscopy ((19)F MRS) is an indispensable tool for assessing the pharmacokinetics of fluorinated drugs. Since the metabolism of 5-fluorouracil (5FU), a frequently used cytotoxic drug, is expected to be different in normal liver and in tumor tissue, spatial localization is required for

  5. New perspectives of 19F MAS NMR in the characterization of amorphous forms of atorvastatin in dosage formulations

    Czech Academy of Sciences Publication Activity Database

    Brus, Jiří; Urbanová, Martina; Šeděnková, Ivana; Brusová, H.

    2011-01-01

    Roč. 409, 1/2 (2011), s. 62-74 ISSN 0378-5173 R&D Projects: GA MŠk 2B08021 Institutional research plan: CEZ:AV0Z40500505 Keywords : 19F MAS NMR * factor analysis * polymorphism Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.350, year: 2011

  6. Theoretical hyperfine structures of 19F i and 17O i

    Science.gov (United States)

    Aourir, Nouria; Nemouchi, Messaoud; Godefroid, Michel; Jönsson, Per

    2018-03-01

    Multiconfiguration Hartree-Fock (MCHF) and multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations are performed for the 2 p5P2o , 2 p4(3P ) 3 s 4P , 2 p4(3P ) 3 s 2P , and 2 p4(3P ) 3 p 4So states of 19F i to determine their hyperfine constants. Several computing strategies are considered to investigate electron correlation and relativistic effects. High-order correlation contributions are included in MCHF calculations based on single and double multireference expansions. The largest components of the single reference MCHF wave functions are selected to define the multireference (MR) sets. In this scheme, relativistic corrections are evaluated in the Breit-Pauli approximation. A similar strategy is used for the calculation of MCDHF relativistic wave functions and hyperfine parameters. While correlation and relativistic corrections are found to be rather small for the ground state, we highlight large relativistic effects on the hyperfine constant A3 /2 of 2 p4(3P ) 3 p 4So and, to a lesser extent, on A1 /2 of 2 p4(3P ) 3 s 4P . As expected for such a light system, electron correlation effects dominate over relativity in the calculation of the hyperfine interaction of all other levels considered. We also revisit the hyperfine constants of 2 p3(4S ) 3 s S5o and 2 p3(4S ) 3 p 5P in 17O using similar strategies. The results are found to be in excellent agreement with experiment.

  7. The combined application of {sup 1}H MRI and {sup 19}F MRS to the study of cerebroprotection

    Energy Technology Data Exchange (ETDEWEB)

    Haga, K.K

    2000-07-01

    The research presented in this thesis focuses on the application of {sup 1}H and {sup 19}F nuclear magnetic resonance techniques to the evaluation of the neuroprotective and pharmacokinetic properties of a novel, nitric oxide synthase inhibitor in a rat model of stroke. Although there is a growing body of research on the application of {sup 19}F magnetic resonance spectroscopy techniques to the study of psychotropic agents, this is the first attempt to apply these methods to the evaluation of an agent being developed for cerebroprotection. TRIM, 1-(2-trifluoromethylphenyl) imidazole, is a selective inhibitor of the neuronal form of nitric oxide synthase in the rat and mouse brain. The first portion of this thesis demonstrates TRIM's neuroprotective properties when administered post-occlusion in the middle cerebral artery occlusion model of focal cerebral ischaemia. In addition, these neuroprotective effects may be eliminated by the co-administration of L-arginine, a nitric oxide precursor, indicating a role for neuronal nitric oxide synthase in ischaemic damage. {sup 1}H magnetic resonance imaging at 24 hours post-occlusion indicates a 40% reduction in lesion volume following TRIM administration as compared to the saline control group. The second part of this thesis pertains to the development and application of {sup 19}F MRS methods, in vivo and in vitro, to enable the investigator to monitor and quantify TRIM in the rat CNS pre and post-occlusion. In this section, {sup 19}F MRS studies were conducted to measure the in vivo T{sub 1} and T{sub 2} relaxation parameters and subsequently, the concentration of TRIM achieved in the rat CNS over an 8 hour measuring period. From this data, the in vivo pharmacokinetics of TRIM were evaluated and applied to the neuroprotective strategy in cerebral ischaemia. In vitro measurements of TRIM concentrations in the rat CNS were compared to the in vivo concentration calculations to evaluate the reliability of TRIM

  8. {sup 19}F-labeling of the adenine H2-site to study large RNAs by NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sochor, F. [Johann Wolfgang Goethe-University Frankfurt, Institut für Organische Chemie und Chemische Biologie, Center for Biomolecular Magnetic Resonance (BMRZ) (Germany); Silvers, R. [Massachusetts Institute of Technology, Department of Chemistry, Francis Bitter Magnet Laboratory (United States); Müller, D.; Richter, C.; Fürtig, B., E-mail: fuertig@nmr.uni-frankfurt.de; Schwalbe, H., E-mail: schwalbe@nmr.uni-frankfurt.de [Johann Wolfgang Goethe-University Frankfurt, Institut für Organische Chemie und Chemische Biologie, Center for Biomolecular Magnetic Resonance (BMRZ) (Germany)

    2016-01-15

    In comparison to proteins and protein complexes, the size of RNA amenable to NMR studies is limited despite the development of new isotopic labeling strategies including deuteration and ligation of differentially labeled RNAs. Due to the restricted chemical shift dispersion in only four different nucleotides spectral resolution remains limited in larger RNAs. Labeling RNAs with the NMR-active nucleus {sup 19}F has previously been introduced for small RNAs up to 40 nucleotides (nt). In the presented work, we study the natural occurring RNA aptamer domain of the guanine-sensing riboswitch comprising 73 nucleotides from Bacillus subtilis. The work includes protocols for improved in vitro transcription of 2-fluoroadenosine-5′-triphosphat (2F-ATP) using the mutant P266L of the T7 RNA polymerase. Our NMR analysis shows that the secondary and tertiary structure of the riboswitch is fully maintained and that the specific binding of the cognate ligand hypoxanthine is not impaired by the introduction of the {sup 19}F isotope. The thermal stability of the {sup 19}F-labeled riboswitch is not altered compared to the unmodified sequence, but local base pair stabilities, as measured by hydrogen exchange experiments, are modulated. The characteristic change in the chemical shift of the imino resonances detected in a {sup 1}H,{sup 15}N-HSQC allow the identification of Watson–Crick base paired uridine signals and the {sup 19}F resonances can be used as reporters for tertiary and secondary structure transitions, confirming the potential of {sup 19}F-labeling even for sizeable RNAs in the range of 70 nucleotides.

  9. 19F-labeling of the adenine H2-site to study large RNAs by NMR spectroscopy

    International Nuclear Information System (INIS)

    Sochor, F.; Silvers, R.; Müller, D.; Richter, C.; Fürtig, B.; Schwalbe, H.

    2016-01-01

    In comparison to proteins and protein complexes, the size of RNA amenable to NMR studies is limited despite the development of new isotopic labeling strategies including deuteration and ligation of differentially labeled RNAs. Due to the restricted chemical shift dispersion in only four different nucleotides spectral resolution remains limited in larger RNAs. Labeling RNAs with the NMR-active nucleus 19 F has previously been introduced for small RNAs up to 40 nucleotides (nt). In the presented work, we study the natural occurring RNA aptamer domain of the guanine-sensing riboswitch comprising 73 nucleotides from Bacillus subtilis. The work includes protocols for improved in vitro transcription of 2-fluoroadenosine-5′-triphosphat (2F-ATP) using the mutant P266L of the T7 RNA polymerase. Our NMR analysis shows that the secondary and tertiary structure of the riboswitch is fully maintained and that the specific binding of the cognate ligand hypoxanthine is not impaired by the introduction of the 19 F isotope. The thermal stability of the 19 F-labeled riboswitch is not altered compared to the unmodified sequence, but local base pair stabilities, as measured by hydrogen exchange experiments, are modulated. The characteristic change in the chemical shift of the imino resonances detected in a 1 H, 15 N-HSQC allow the identification of Watson–Crick base paired uridine signals and the 19 F resonances can be used as reporters for tertiary and secondary structure transitions, confirming the potential of 19 F-labeling even for sizeable RNAs in the range of 70 nucleotides

  10. In-Vivo Detection and Tracking of T Cells in Various Organs in a Melanoma Tumor Model by 19F-Fluorine MRS/MRI.

    Directory of Open Access Journals (Sweden)

    Christine Gonzales

    Full Text Available 19F-MRI and 19F-MRS can identify specific cell types after in-vitro or in-vivo 19F-labeling. Knowledge on the potential to track in-vitro 19F-labeled immune cells in tumor models by 19F-MRI/MRS is scarce.To study 19F-based MR techniques for in-vivo tracking of adoptively transferred immune cells after in-vitro 19F-labeling, i.e. to detect and monitor their migration non-invasively in melanoma-bearing mice.Splenocytes (SP were labeled in-vitro with a perfluorocarbon (PFC and IV-injected into non-tumor bearing mice. In-vitro PFC-labeled ovalbumin (OVA-specific T cells from the T cell receptor-transgenic line OT-1, activated with anti-CD3 and anti-CD28 antibodies (Tact or OVA-peptide pulsed antigen presenting cells (TOVA-act, were injected into B16 OVA melanoma-bearing mice. The distribution of the 19F-labelled donor cells was determined in-vivo by 19F-MRI/MRS. In-vivo 19F-MRI/MRS results were confirmed by ex-vivo 19F-NMR and flow cytometry.SP, Tact, and TOVA-act were successfully PFC-labeled in-vitro yielding 3x1011-1.4x1012 19F-atoms/cell in the 3 groups. Adoptively transferred 19F-labeled SP, TOVA-act, and Tact were detected by coil-localized 19F-MRS in the chest, abdomen, and left flank in most animals (corresponding to lungs, livers, and spleens, respectively, with highest signal-to-noise for SP vs TOVA-act and Tact, p<0.009 for both. SP and Tact were successfully imaged by 19F-MRI (n = 3; liver. These in-vivo data were confirmed by ex-vivo high-resolution 19F-NMR-spectroscopy. By flow cytometric analysis, however, TOVA-act tended to be more abundant versus SP and Tact (liver: p = 0.1313; lungs: p = 0.1073; spleen: p = 0.109. Unlike 19F-MRI/MRS, flow cytometry also identified transferred immune cells (SP, Tact, and TOVA-act in the tumors.SP, Tact, and TOVA-act were successfully PFC-labeled in-vitro and detected in-vivo by non-invasive 19F-MRS/MRI in liver, lung, and spleen. The portion of 19F-labeled T cells in the adoptively transferred cell

  11. 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

  12. 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...

  13. Inelastic pion scattering by 13C at low energies

    International Nuclear Information System (INIS)

    Mitchell, J.H.

    1987-03-01

    Angular distributions for inelastically scattered pions were obtained for several states in 13 C at an incident energy of 65 MeV. The data include results from both π + and π - measurements. In addition, π - measurements were made at T/sub π/ = 50 MeV at one angle to give a two point fixed-q excitation function. The data are compared to theory and the data of others. As might be expected, medium corrections are shown to be considerably more important at low energies than at resonance. This is true for inelastic transitions of multipolarity 0,2 and 3. Parameters derived from an analysis of elastic pion scattering and SCX data also provide an adequate description of the inelastic transitions. The charge asymmetry in the cross sections for the 9/2 + state that was seen at resonance persists at these energies. This result is consistent with an impulse approximation treatment of the spin-flip amplitude. This is true even though the incoming energy of the pions is far below the range where the validity of an impulse treatment is expected. 65 refs., 45 figs

  14. 13C CPMAS NMR Studies of Anthocyanidins and their Glucosides

    International Nuclear Information System (INIS)

    Wolniak, M.; Wawer, I.

    2005-01-01

    Anthocyanins are responsible for red, purple or blue colours of flower petals and can be found in red or black fruits and berries. Many foods, especially red grapes and wines, aronia or blueberries contain large amounts of anthocyanins. Their health beneficial effects are related to antioxidant and radical scavenging properties. Structural analysis of anthocyanins by NMR are few, owing to the difficulty in obtaining analysable spectra for unstable, interconverting compounds, available in small amounts. Compounds studied by us were isolated from fruits and berries. 13 C CPMAS NMR spectra were recorded on a Bruker DSX-400 spectrometer for solid chlorides of: cyanidin, cyanidin 3-O-glucoside, cyanidin 3,5-O-diglucoside, pelargonidin and pelargonidin 3-O-glucoside. Dipolar dephased and short contact pulse sequences were used as an aid in the assignment of resonances in CPMAS spectra of solids. Inspection of the spectra indicates that anthocyanidins are in the form of flavylium (cationic) and not in form of the chalcone.: the resonance of C2 appears at ca. 160 ppm and C3 at ca. 135 ppm, whereas C ring opening produces C2 = O, for which chemical shift of ca. 180 ppm can be expected. A comparison of experimental (CPMAS) and predicted (GIAO DFT) shielding constants for cyanidin provided information about the orientation of OH groups, twist angle of aromatic ring B and the localization of the chloride anion.(author)

  15. 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.

  16. [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%.

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

    KAUST Repository

    Abou-Hamad, E.

    2011-10-10

    We present a detailed experimental and theoretical study on how structural properties of carbon nanotubes can be derived from 13C NMR investigations. Magic angle spinning solid state NMR experiments have been performed on single- and multiwalled carbon nanotubes with diameters in the range from 0.7 to 100 nm and with number of walls from 1 to 90. We provide models on how diameter and the number of nanotube walls influence NMR linewidth and line position. Both models are supported by theoretical calculations. Increasing the diameter D, from the smallest investigated nanotube, which in our study corresponds to the inner nanotube of a double-walled tube to the largest studied diameter, corresponding to large multiwalled nanotubes, leads to a 23.5 ppm diamagnetic shift of the isotropic NMR line position δ. We show that the isotropic line follows the relation δ = 18.3/D + 102.5 ppm, where D is the diameter of the tube and NMR line position δ is relative to tetramethylsilane. The relation asymptotically tends to approach the line position expected in graphene. A characteristic broadening of the line shape is observed with the increasing number of walls. This feature can be rationalized by an isotropic shift distribution originating from different diamagnetic shielding of the encapsulated nanotubes together with a heterogeneity of the samples. Based on our results, NMR is shown to be a nondestructive spectroscopic method that can be used as a complementary method to, for example, transmission electron microscopy to obtain structural information for carbon nanotubes, especially bulk samples.

  18. 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

  19. Determination of tea fluorine concentration with 19F(p, αγ)16O prompt nuclear reaction analysis

    International Nuclear Information System (INIS)

    Liang Daihua; Shen Guantao; Li Deyi; Wu Junheng

    1987-01-01

    Experiments of 19 F(p, αγ) 16 O prompt nuclear reaction analyses of tea F contents were performed on a Cockroft-Walton accelerator. The principle and apparatus are described. More than 150 varieties tea samples were examined. Results show that for the same variety of tea samples, the higher the grade of the tea, the higher the F concentration it contains, and for different varieties, the better the tea, the lower the F concentration of the tea

  20. Preliminary study of the 19F(7Li,7Be)19O reaction at 52 MeV with MAGNEX

    CERN Document Server

    Cavallaro, M; Cappuzzello, F; Carbone, D; Foti, A; Orrigo, S E A; Rodrigues, M R D; Schillaci, M; Borello-Lewin, T; Petrascu, H

    2010-01-01

    The 19F(7Li,7Be)19O charge-exchange reaction at 52 MeV incident energy has been performed at INFN-LNS in Catania using the MAGNEX spectrometer. The use of an algebraic ray-reconstruction technique has allowed to extract the 19O excitation energy spectrum and the experimental angular distributions obtained with a single angular setting of the spectrometer.

  1. Characterization of solid polymer dispersions of active pharmaceutical ingredients by 19F MAS NMR and factor analysis

    Czech Academy of Sciences Publication Activity Database

    Urbanová, Martina; Brus, Jiří; Šeděnková, Ivana; Policianová, Olivia; Kobera, Libor

    2013-01-01

    Roč. 100, 1 January (2013), s. 59-66 ISSN 1386-1425 R&D Projects: GA ČR GPP106/11/P426; GA MŠk 2B08021 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : solid-state NMR * factor analysis * 19F MAS NMR Subject RIV: FR - Pharmacology ; Medidal Chemistry Impact factor: 2.129, year: 2013

  2. Fluctuation phenomena for dissipative processes in 19 F + 27 Al system

    International Nuclear Information System (INIS)

    BerceanuI, I.; Andronic, A.; Duma, M.; Moisa, D.; Petrovici, M.; Pop, A.; Simion, V.; Del Zoppo, A.; D'Erasmo, G.; Imme, G.; Lanzano, G.; Pagano, A.; Raciti, G.; Pantaleo, A.

    2000-01-01

    Non-statistical fluctuations in the excitation functions (EF) of dissipative heavy ion collisions (DHIC) were rather unexpected, the cross sections being always obtained on a 'coarse cell' of total kinetic energy and center of mass angle (θ cm ). Since the experimental fluctuations in the EF for DHIC have been evidenced, the time evolution of dinuclear system (DNS) with different mass asymmetries and total mass ≤108 has been investigated only by statistical analysis. Although many theoretical interpretations of excitation function fluctuations ground their assumptions on the observed large angular correlation, the experimental angular correlation data are rather scarce. We already reported preliminary results concerning angular correlation for DHIC in the 19 F + 27 Al interaction. In the present work the angular correlation analysis was realized for E lab = 116.75 - 129.75 MeV with a 2 angle binning in the angular distributions and total kinetic energy loss (TKEL) windows of 20±2.5, 30±2.5 and 40±2.5 MeV. Pronounced oscillations in the angular distributions, at some incident energies, were observed. These oscillations are nicely evidenced in the autocorrelation angular functions (AAF) as determined for fragments with atomic number Z = 8 at an incident energy 124.75 MeV. A decreasing number of the oscillations with increasing TKEL value could be observed. The AAFs were calculated using for the average cross section the value obtained from the fit of the angular distributions with formula: sigma/dθ cm ∝ [exp(-θ cm /ω·τ) + exp(-(2π-θ cm )/ω·τ)], where ω and τ are the angular velocity and lifetime of DNS, respectively. The moving Gaussian procedure was used for calculating the angular cross correlation coefficients C(θ,θ') for the energy averaged cross section . The results are presented. Large values for C(θ,θ') with an oscillating pattern were obtained for all studied fragments (Z = 6-8, 10). An increasing trend of C(θ,θ') values with TKEL

  3. The synthesis of [2-13C]2-nitropropane at room temperature and at atmospheric pressure

    OpenAIRE

    Jacquemijns M; Zomer G

    1990-01-01

    In this report the synthesis of [2-13C]2-nitropropane at room temperature is described. [2-13C]Acetone was converted into the oxime with hydroxy hydrochloridelamine and sodium carbonate. Treatment with hypobromic acid resulted in 2-13C]2-bromo-2-nitropropane. Hydrogenation with sodium borohydride gave [2-13C]2-nitropropane in 14,3% overall yield.

  4. Excitation functions of pion reactions on 14N, 16O, and 19F through the (3,3) resonance

    International Nuclear Information System (INIS)

    Jacob, N.P. Jr.; Markowitz, S.S.

    1976-01-01

    Cross sections for pion-induced reactions of the form (π,πN) and more complex spallation reactions of the form (π,X) have been measured from 50--550 MeV on the target nuclei 14 N, 16 O, and 19 F using the secondary pion beams at the Lawrence Berkeley Laboratory 184-inch synchrocyclotron and the Clinton P. Anderson Meson Physics Facility. The dominance of the (3,3) free-particle resonance is seen in all excitation functions determined in this work. Relative to the 12 C(π/sup plus-or-minus/,πN) 11 C reactions, the (π/sup plus-or-minus/,πN) reactions on 14 N, 16 O, and 19 F have magnitudes of 0.2, 1, and 0.7, respectively. The cross section ratio R=sigma (π - ,π - n)/sigma (π + ,π N) =1.68+-0.18 for 14 N at 188+-15 MeV, 1.68+-0.05 for 16 O at 188+-9 MeV, and 1.68+-0.03 for 19 F at 178+-2 MeV incident pion energy. The results from this work are compared to previous pion work, analogous proton-induced reactions, Monte Carlo intranuclear cascade-evaporation calculations, and to a semiclassical nucleon charge-exchange model which convincingly explains the (π,πN) reaction mechanism in the (3,3) resonance region

  5. 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.

  6. Espiritu Santo, Vanuatu Stable Isotope (delta 18O, delta 13C) Data for 1806 to 1979

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Site: Espiritu Santo Island, Vanuatu, 15S, 167E. 173 year record of d18O and d13C. Variable names: QSR Age, QSR 13C, QSR 18O, GRL Age, GRL Qtrly 13C, GRL Qtrly 18O,...

  7. 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...

  8. The synthesis of [2-13C]2-nitropropane at room temperature and at atmospheric pressure

    NARCIS (Netherlands)

    Jacquemijns M; Zomer G

    1990-01-01

    In this report the synthesis of [2-13C]2-nitropropane at room temperature is described. [2-13C]Acetone was converted into the oxime with hydroxy hydrochloridelamine and sodium carbonate. Treatment with hypobromic acid resulted in 2-13C]2-bromo-2-nitropropane. Hydrogenation with sodium borohydride

  9. Synthesis and Physicochemical Properties of [19,20-13C]-17α-Ethinylestradiol

    NARCIS (Netherlands)

    Kraan, G.P.B.; Drayer, N.M.; Kruizinga, W.H.; Vaalburg, W.; Hummelen, J.C.

    1989-01-01

    13C2-17α-ethinylestradiol (13C2-EE2) was synthesized from estrone and 13C2-C2H2-gas to measure the metabolic clearance rate and the plasma concentration of 17α-ethinylestradiol (EE2) in tall girls, who are treated with high dosages of this estrogen. Interesting characteristics determined by (i) MS:

  10. NbF5 and TaF5: Assignment of 19F NMR resonances and chemical bond analysis from GIPAW calculations

    International Nuclear Information System (INIS)

    Biswal, Mamata; Body, Monique; Legein, Christophe; Sadoc, Aymeric; Boucher, Florent

    2013-01-01

    The 19 F isotropic chemical shifts (δ iso ) of two isomorphic compounds, NbF 5 and TaF 5 , which involve six nonequivalent fluorine sites, have been experimentally determined from the reconstruction of 1D 19 F MAS NMR spectra. In parallel, the corresponding 19 F chemical shielding tensors have been calculated using the GIPAW method for both experimental and DFT-optimized structures. Furthermore, the [M 4 F 20 ] units of NbF 5 and TaF 5 being held together by van der Waals interactions, the relevance of Grimme corrections to the DFT optimization processes has been evaluated. However, the semi-empirical dispersion correction term introduced by such a method does not show any significant improvement. Nonetheless, a complete and convincing assignment of the 19 F NMR lines of NbF 5 and TaF 5 is obtained, ensured by the linearity between experimental 19 F δ iso values and calculated 19 F isotropic chemical shielding σ iso values. The effects of the geometry optimizations have been carefully analyzed, confirming among other matters, the inaccuracy of the experimental structure of NbF 5 . The relationships between the fluorine chemical shifts, the nature of the fluorine atoms (bridging or terminal), the position of the terminal ones (opposite or perpendicular to the bridging ones), the fluorine charges, the ionicity and the length of the M–F bonds have been established. Additionally, for three of the 19 F NMR lines of NbF 5 , distorted multiplets, arising from 1 J-coupling and residual dipolar coupling between the 19 F and 93 Nb nuclei, were simulated yielding to values of 93 Nb– 19 F 1 J-coupling for the corresponding fluorine sites. - Graphical abstract: The complete assignment of the 19 F NMR lines of NbF 5 and TaF 5 allow establishing relationships between the 19 F δ iso values, the nature of the fluorine atoms (bridging or terminal), the position of the terminal ones (opposite or perpendicular to the bridging ones), the fluorine charges, the ionicity and the

  11. 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

  12. 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

  13. Acetylenes bearing Aromatic Terminal Groups. : II 13C-NMR Spectra of Monosubstituted Diphenylacetylenes

    OpenAIRE

    野本, 健雄; Nomoto, Takeo

    1986-01-01

    Six monosubstituted diphenylacetylenes, p-X-C6H4-C≡C-C6H5 1 (Ⅹ=NMe2, NH2, OMe, Cl, and NO2), were synthesized, and 13C-NMR spectra of their acetylenic carbons were measured. Hammett plots of the chemical shifts of the acetylenic α-13C and β-13C (against substituent constants σ) respectively showed a linear relationship, eXCept for β-13C on NMe2 and NH2 groups. The effects of substituents on 13C-Chemical shifts of diphenylacetylenes and effeciency of the C≡C bonds in transmitting the substitue...

  14. 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

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-03-01

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

  17. 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.

  18. 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

  19. 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.

  20. A generalized strategy for designing (19)F/(1)H dual-frequency MRI coil for small animal imaging at 4.7 Tesla.

    Science.gov (United States)

    Hu, Lingzhi; Hockett, Frank D; Chen, Junjie; Zhang, Lei; Caruthers, Shelton D; Lanza, Gregory M; Wickline, Samuel A

    2011-07-01

    To propose and test a universal strategy for building (19) F/(1) H dual-frequency RF coil that permits multiple coil geometries. The feasibility to design (19) F/(1) H dual-frequency RF coil based on coupled resonator model was investigated. A series capacitive matching network enables robust impedance matching for both harmonic oscillating modes of the coupled resonator. Two typical designs of (19) F/(1) H volume coils (birdcage and saddle) at 4.7T were implemented and evaluated with electrical bench test and in vivo (19) F/(1) H dual-nuclei imaging. For various combinations of internal resistances of the sample coil and secondary resonator, numerical solutions for the tunable capacitors to optimize impedance matching were obtained using a root-seeking program. Identical and homogeneous B1 field distribution at (19) F and (1) H frequencies were observed in bench test and phantom image. Finally, in vivo mouse imaging confirmed the sensitivity and homogeneity of the (19) F/(1) H dual-frequency coil design. A generalized strategy for designing (19) F/(1) H dual-frequency coils based on the coupled resonator approach was developed and validated. A unique feature of this design is that it preserves the B1 field homogeneity of the RF coil at both resonant frequencies. Thus it minimizes the susceptibility effect on image co-registration. Copyright © 2011 Wiley-Liss, Inc.

  1. 'Boomerang'-like insertion of a fusogenic peptide in a lipid membrane revealed by solid-state 19F NMR.

    Science.gov (United States)

    Afonin, Sergii; Dürr, Ulrich H N; Glaser, Ralf W; Ulrich, Anne S

    2004-02-01

    Solid state (19)F NMR revealed the conformation and alignment of the fusogenic peptide sequence B18 from the sea urchin fertilization protein bindin embedded in flat phospholipid bilayers. Single (19)F labels were introduced into nine distinct positions along the wild-type sequence by substituting each hydrophobic amino acid, one by one, with L-4-fluorophenylglycine. Their anisotropic chemical shifts were measured in uniaxially oriented membrane samples and used as orientational constraints to model the peptide structure in the membrane-bound state. Previous (1)H NMR studies of B18 in 30% TFE and in detergent micelles had shown that the peptide structure consists of two alpha-helical segments that are connected by a flexible hinge. This helix-break-helix motif was confirmed here by the solid-state (19)F NMR data, while no other secondary structure (beta-sheet, 3(10)-helix) was compatible with the set of orientational constraints. For both alpha-helical segments we found that the helical conformation extends all the way to the respective N- and C-termini of the peptide. Analysis of the corresponding tilt and azimuthal rotation angles showed that the N-terminal helix of B18 is immersed obliquely into the bilayer (at a tilt angle tau approximately 54 degrees), whereas the C-terminus is peripherally aligned (tau approximately 91 degrees). The azimuthal orientation of the two segments is consistent with the amphiphilic distribution of side-chains. The observed 'boomerang'-like mode of insertion into the membrane may thus explain how peptide binding leads to lipid dehydration and acyl chain perturbation as a prerequisite for bilayer fusion to occur. Copyright 2004 John Wiley & Sons, Ltd.

  2. In vivo 19F-MRS observation of 5-FU metabolism in fatty liver induced by choline-deficient diet

    International Nuclear Information System (INIS)

    Otsuka, Hideki; Harada, Masafumi; Nishitani, Hiromu; Koga, Keiko.

    1996-01-01

    Using 19 F-MRS, 5-FU metabolism was investigated in rat fatty liver. Fatty liver was induced by choline-deficient diet (CD diet). This study showed differences in 5-FU metabolism between normal and fatty liver. After laparotomy, a surface coil was placed directly on the liver surface. Spectra were continuously obtained after injection of 5-FU 100 mg/kg body weight via a catheter inserted into femoral vein. We made MRI and 1 H-MRS study to examine the lipid accumulation. Histological study was also performed using HE (hematoxylin-eosin) and oil red stain. The livers of rats fed a CD diet showed very high intensity on T 1 -WI. 1 H-MRS was very useful in deteminating the fat content because the fat ratio demonstrated by 1 H-MRS is well correlated to histological findings. In 19 F-MRS, we recognized the following four peaks: 5-FU, FBAL, Fnct (fluoronucleotide) and FUPA. The decrease of 5-FU was not very apparent, but compared to the normal liver, the formation of Fnct increased and the formation of FBAL was suppressed in fatty liver. The rats fed a CD diet for four weeks showed a higher Fnct peak and lower FBAL peak compared with the results of rats fed a CD diet for two weeks. In a CD diet group, liver cell degeneration and necrotic changes were observed histologically. It is reported that cell degeneration is followed by cell proliferation in fatty liver induced by a choline deficient diet, and the high Fnct peak found in our study may reflect this phenomenon. The high Fnct peak on 19 F-MRS may correspond to recovering reaction from liver injury like fatty liver. (author)

  3. A comparison of chemical shift sensitivity of trifluoromethyl tags: optimizing resolution in {sup 19}F NMR studies of proteins

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Libin; Larda, Sacha Thierry; Frank Li, Yi Feng [University of Toronto, UTM, Department of Chemistry (Canada); Manglik, Aashish [Stanford University School of Medicine, Department of Molecular and Cellular Physiology (United States); Prosser, R. Scott, E-mail: scott.prosser@utoronto.ca [University of Toronto, UTM, Department of Chemistry (Canada)

    2015-05-15

    The elucidation of distinct protein conformers or states by fluorine ({sup 19}F) NMR requires fluorinated moieties whose chemical shifts are most sensitive to subtle changes in the local dielectric and magnetic shielding environment. In this study we evaluate the effective chemical shift dispersion of a number of thiol-reactive trifluoromethyl probes [i.e. 2-bromo-N-(4-(trifluoromethyl)phenyl)acetamide (BTFMA), N-(4-bromo-3-(trifluoromethyl)phenyl)acetamide (3-BTFMA), 3-bromo-1,1,1-trifluoropropan-2-ol (BTFP), 1-bromo-3,3,4,4,4-pentafluorobutan-2-one (BPFB), 3-bromo-1,1,1-trifluoropropan-2-one (BTFA), and 2,2,2-trifluoroethyl-1-thiol (TFET)] under conditions of varying polarity. In considering the sensitivity of the {sup 19}F NMR chemical shift to the local environment, a series of methanol/water mixtures were prepared, ranging from relatively non-polar (MeOH:H{sub 2}O = 4) to polar (MeOH:H{sub 2}O = 0.25). {sup 19}F NMR spectra of the tripeptide, glutathione ((2S)-2-amino-4-{[(1R)-1-[(carboxymethyl)carbamoyl] -2-sulfanylethyl]carbamoyl}butanoic acid), conjugated to each of the above trifluoromethyl probes, revealed that the BTFMA tag exhibited a significantly greater range of chemical shift as a function of solvent polarity than did either BTFA or TFET. DFT calculations using the B3LYP hybrid functional and the 6-31G(d,p) basis set, confirmed the observed trend in chemical shift dispersion with solvent polarity.

  4. DFT-GIAO calculation of properties of {sup 19}F NMR and stability study of environmentally relevant perfluoroalkylsulfonamides (PFASAmide)

    Energy Technology Data Exchange (ETDEWEB)

    Mejia-Urueta, Rafael; Mestre-Quintero, Kleyber; Vivas-Reyes, Ricardo, E-mail: rvivasr@unicartagena.edu.co [Grupo de Quimica Cuantica y Teorica, Facultad de Ciencias Exactas y Naturales, Universidad de Cartagena, Cartagena (Colombia)

    2011-09-15

    Perfluorinated organic compounds (POCs), such as perfluorooctanesulfonate (PFOS) and perfluoroalkylsulfonamide (PFASA) are compounds that have recently attracted considerable attention worldwide because of its high persistence and wide distribution in the environment. Among the spectroscopic methods used to study the PFASA, {sup 19}F nuclear magnetic resonance (NMR {sup 19}F) is very effective, due to its ability to determine concentrations of PFASA in biological samples and measure pollution in water samples. For this reason, a theoretical study of the properties of {sup 19}F NMR was performed. In this study we have determined the shielding constant ({sigma}) for different fluorine nucleus of the 18 molecules under study, using density functional theory (DFT) and GIAO method with the B3PW91/6-31+G(d,p) level of calculation. The {sigma} calculations were made at vacuum and in presence of a solvent. The values of chemical shifts ({delta}), were also calculated in a different level of theory. The best results were obtained with the level of calculation DFT-GIAO/B3PW91/6-31+G(d,p) by considering the solvent such as dimethylsulfoxide (DMSO), chloroform (CHCl{sub 3}), acetone (CH{sub 3}COCH{sub 3}) and methanol (CH{sup 3}OH). The results were interpreted in terms of calculated hardness at DFT/B3PW91/6-31+G(d, p) level. The behaviour of the hardness was higher in the molecules of four carbons PFASA than eight carbons. This explain theoretically resistance of four carbons PFAS to be transformed into perfluorobutanesulfonate (PFBS). (author)

  5. L-subshell ionization studies in Au and Bi for 19F and 28Si large-ion bombardment

    International Nuclear Information System (INIS)

    Padhi, H.C.; Dhal, B.B.; Nanal, V.; Prasad, K.G.; Tandon, P.N.; Trautmann, D.

    1996-01-01

    L x-ray production and subshell ionization cross sections of Au and Bi have been measured for the bombardment of 19 F and 28 Si ions in the energy range 30 endash 57 MeV and 36 endash 84 MeV, respectively. Comparison of the Lα x-ray production cross sections of Au with the earlier data by Malhi and Gray [Phys. Rev. A 44, 7199 (1991)] shows reasonable agreement for 19 F impact and their data are consistently higher for 28 Si at all energies. The measured Lα line energy shows a shift towards higher energy, which appears to be proportional to the square of the projectile atomic number at all impact energies. This shift suggests the presence of multiple ionization in the L and M shells with a simultaneous production of four M holes in Au at the impact energy of 3 MeVu -1 of 28 Si. The L-subshell ionization cross sections obtained from the measured x-ray production cross sections have been compared with the semiclassical approximation and perturbed stationary state theory with energy loss, Coulomb deflection, and relativistic correction for the electron motion calculations, which show large deviations for the L 1 subshell. The L 2 - and L 3 -subshell ionization cross sections are underestimated by both the theories by a factor of 1.2 endash 4.0 for 28 Si impact whereas for the 19 F case there is reasonable agreement for the L 3 cross section but the L 2 cross section is underestimated by 20 endash 30%. copyright 1996 The American Physical Society

  6. DFT-GIAO calculation of properties of 19F NMR and stability study of environmentally relevant perfluoroalkylsulfonamides (PFASAmide)

    International Nuclear Information System (INIS)

    Mejia-Urueta, Rafael; Mestre-Quintero, Kleyber; Vivas-Reyes, Ricardo

    2011-01-01

    Perfluorinated organic compounds (POCs), such as perfluorooctanesulfonate (PFOS) and perfluoroalkylsulfonamide (PFASA) are compounds that have recently attracted considerable attention worldwide because of its high persistence and wide distribution in the environment. Among the spectroscopic methods used to study the PFASA, 19 F nuclear magnetic resonance (NMR 19 F) is very effective, due to its ability to determine concentrations of PFASA in biological samples and measure pollution in water samples. For this reason, a theoretical study of the properties of 19 F NMR was performed. In this study we have determined the shielding constant (σ) for different fluorine nucleus of the 18 molecules under study, using density functional theory (DFT) and GIAO method with the B3PW91/6-31+G(d,p) level of calculation. The σ calculations were made at vacuum and in presence of a solvent. The values of chemical shifts (δ), were also calculated in a different level of theory. The best results were obtained with the level of calculation DFT-GIAO/B3PW91/6-31+G(d,p) by considering the solvent such as dimethylsulfoxide (DMSO), chloroform (CHCl 3 ), acetone (CH 3 COCH 3 ) and methanol (CH 3 OH). The results were interpreted in terms of calculated hardness at DFT/B3PW91/6-31+G(d, p) level. The behaviour of the hardness was higher in the molecules of four carbons PFASA than eight carbons. This explain theoretically resistance of four carbons PFAS to be transformed into perfluorobutanesulfonate (PFBS). (author)

  7. What is hiding behind ontogenic d13C variations in mollusk shells: New insights from scallops.

    Science.gov (United States)

    Chauvaud, L.; Lorrain, A.; Gillikin, D. P.; Thebault, J.; Paulet, Y.; Strand, O.; Blamart, D.; Guarini, J.; Clavier, J.

    2008-12-01

    We examined d13Ccalcite variations along scallop shells (Pecten maximus) sampled in Norway, France and Spain. Time series of shell calcite d13C show a consistent pattern of decreasing d13C with age. This almost linear d13C trend reflects an increasing contribution of metabolic CO2 to skeletal carbonate throughout ontogeny. We have removed this ontogenic trend to try to extract other information from our shell calcite d13C dataset. Scallops from the Bay of Brest (western Brittany, France) were then used to interpret the data as many environmental parameters were available for this site. d13Ccalcite variations were compared to d13C of dissolved inorganic carbon (DIC) and Chl a. The detrended calcite d13C profiles seem to follow a seasonal pattern, but surprisingly are inversely related to the d13C DIC and chlorophyll a concentrations measured within the water column. Theses results suggest that shell d13C variations are not controlled by isotopic variation of DIC. Since scallops eat phytoplankton and microphytobenthos cells, and, as a consequence respire organic mater largely depleted in 13C, we therefore suggest that in mollusk suspension feeders the shell d13Ccalcite might still be used to track the annual number of phytoplankton blooms when d13C values of calcite are detrended. We must consider this trend as a potential biological filter hiding precious environmental records.

  8. Biosynthetically directed fractional 13C labeling facilitates identification of Phe and Tyr aromatic signals in proteins

    International Nuclear Information System (INIS)

    Jacob, Jaison; Louis, John M.; Nesheiwat, Issa; Torchia, Dennis A.

    2002-01-01

    Analysis of 2D [ 13 C, 1 H]-HSQC spectra of biosynthetic fractionally 13 C labeled proteins is a reliable, straightforward means to obtain stereospecific assignments of Val and Leu methyl sites in proteins. Herein we show that the same fractionally labeled protein sample facilitates observation and identification of Phe and Tyr aromatic signals. This is the case, in part, because the fractional 13 C labeling yields aromatic rings in which some of the 13 C- 13 C J-couplings, present in uniformly labeled samples, are absent. Also, the number of homonuclear J-coupling partners differs for the δ-, ε- and ζ-carbons. This enabled us to vary their signal intensities in distinctly different ways by appropriately setting the 13 C constant-time period in 2D [ 13 C, 1 H]-HSQC spectra. We illustrate the application of this approach to an 18 kDa protein, c-VIAF, a modulator of apoptosis. In addition, we show that cancellation of the aromatic 13 C CSA and 13 C- 1 H dipolar interactions can be fruitfully utilized in the case of the fractionally labeled sample to obtain high resolution 13 C constant-time spectra with good sensitivity

  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. Dot Blot para determinar la identidad antigénica en vacunas conjugadas contra Streptococcus pneumoniae serotipo 19F

    Directory of Open Access Journals (Sweden)

    Osmir Cabrera-Blanco

    2017-04-01

    Full Text Available Las autoridades regulatorias recomiendan el uso de técnicas de Resonancia Magnética Nuclear o técnicas serológicas para la determinación de la identidad de los antígenos presentes en las vacunas conjugadas. Con la aparición de las vacunas conjugadas multivalentes, se ha hecho necesario recurrir a técnicas inmunoquímicas con la utilización de anticuerpos monoclonales para aumentar la sensibilidad en la determinación de la identidad de los antígenos en dichas vacunas conjugadas. El objetivo del presente trabajo fue establecer las condiciones óptimas de trabajo que permitieran utilizar la técnica del Dot Blot para determinar la identidad de los antígenos en vacunas conjugadas de Streptococcus pneumoniae serotipo 19F. Para ello se estudiaron los tiempos de incubación, la influencia del reactivo en la solución de bloqueo; también las concentraciones óptimas del anticuerpo monoclonal y de los ingredientes farmacéuticos activos, así como los volúmenes de aplicación óptimos para estos y vacunas. Se utilizó un anticuerpo monoclonal contra el polisacárido capsular del serotipo 19F de neumococo. Las muestras empleadas en este trabajo fueron lotes de ingredientes farmacéuticos activos de conjugados de polisacárido capsular 19F y lotes de un candidato vacunal cubano conjugado heptavalente contra neumococos. Los resultados mostraron que para la determinación de la identidad antigénica fueron suficientes 10 µL de muestras de los principios activos a una concentración de 125 µg/mL e igual volumen para las vacunas heptavalentes. Quedó demostrado que una concentración de 1 µg/mL para el anticuerpo monoclonal y tiempos de incubación de 30 min a 37 °C fueron suficientes para la determinación. Estos resultados permiten concluir que quedaron establecidas las condiciones óptimas de trabajo para determinar la identidad antigénica por Dot Blot del polisacárido capsular de S. pneumoniae serotipo 19F presente en las vacunas

  11. 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

  12. 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

  13. /sup 13/C-/sup 13/C spin-spin coupling constants in structural investigations. I. New method of determining the configuration of oximes and their derivatives

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-07-10

    It was shown that the direct /sup 13/C-/sup 13/C spin-spin coupling constants can be used for the unambiguous identification of the configurational isomers of oximes and their derivatives. The stereospecificity of the constants is explained by the additional contribution from the unshared electron pair of the nitrogen atom to the spin-spin coupling constant between the adjacent carbon nuclei in the cis position.

  14. /sup 13/C-/sup 13/C spin-spin coupling constants in structural investigations. V. The direct carbon-carbon coupling constants in the vinyl group

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-03-10

    The direct spin-spin coupling constants in the vinyl group were measured in 100 mono-substituted ethylene derivatives. The inductive effect of the substituent was found to be the major factor in the variation of this constant and, in some cases, the stereospecific effect of the unshared electron pairs of heteratoms makes a significant contribution to the /sup 13/C-/sup 13/C coupling constants.

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. Biosynthesis of the sesquiterpene germacrene D in Solidago canadensis: 13C and (2)H labeling studies.

    Science.gov (United States)

    Steliopoulos, Panagiotis; Wüst, Matthias; Adam, Klaus-Peter; Mosandl, Armin

    2002-05-01

    The biogenetic origin of the isoprenoid building blocks of the sesquiterpene germacrene D was studied in Solidago canadensis. Feeding experiments were carried out with 1-[5,5-D(2)]deoxy-D-xylulose-5-phosphate (D(2)-DOXP), [5-13C]mevalonolactone (13C-MVL) and [1-13C]-D-glucose. The hydrodistillate of a cut shoot fed with D(2)-DOXP was investigated by enantio-MDGC-MS and the volatile fraction of a shoot supplied with 13C-MVL was examined by GC-C-IRMS. The incorporation of [1-13C]-D-glucose was analyzed by quantitative 13C NMR spectroscopy after isolation of germacrene D from the essential oil. Our labeling studies revealed that the biosynthesis of the C-15 skeleton of sesquiterpene germacrene D in Solidago canadensis proceeds predominantly via the methylerythritol phosphate pathway.

  20. 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)

  1. Unexpected relationships between δ13C and wine grape performance in organic farming

    Directory of Open Access Journals (Sweden)

    Edoardo Antonio Costantino Costantini

    2013-12-01

    Significance and impact of the study: Water nutrition is crucial for wine grape performance. δ13C is a method used to assess vine water status during the growing season and to estimate vine performance. A good performance is expected at moderate stress and intermediate δ13C values. A better knowledge of the interaction between water and nutrient scarcity is needed, as it can affect the use of δ13C to predict vine performance.

  2. 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.

  3. Tumor trapping of 5-fluorouracil: In vivo 19F NMR spectroscopic pharmacokinetics in tumor-bearing humans and rabbits

    International Nuclear Information System (INIS)

    Wolf, W.; Servis, K.L.; El-Tahtawy, A.; Singh, M.; Ray, M.; Shani, J.; Presant, C.A.; King, M.; Wiseman, C.; Blayney, D.; Albright, M.J.; Atkinson, D.; Ong, R.; Barker, P.B.; Ring, R. III

    1990-01-01

    The pharmacokinetics of 5-fluorouracil (5FU) were studied in vivo in patients with discrete tumors and in rabbits bearing VX2 tumors by using 19 F NMR spectroscopy. Free 5FU was detected in the tumors of four of the six patients and in all VX2 tumors but not in normal rabbit tissues. No other metabolites were seen in these tumors, contrary to the extensive catabolism previously documented using 19 F NMR spectroscopy in both human and animal livers. The tumor pool of free 5FU in those human tumors that trapped 5FU was determined to have a half-life of 0.4-2.1 hr, much longer than expected and significantly longer than the half-life of 5FU in blood (5-15 min), whereas the half-life of trapped 5FU in the VX2 tumors ranged from 1.05 to 1.22 hr. These studies document that NMR spectroscopy is clinically feasible in vivo, allows noninvasive pharmacokinetic analyses at a drug-target tissue in real time, and may produce therapeutically important information at the time of drug administration. Demonstration of the trapping of 5FU in tumors provides both a model for studying metabolic modulation in experimental tumors (in animals) and a method for testing modulation strategies clinically (in patients)

  4. Robust refocusing of 13C magnetization in multidimensional NMR experiments by adiabatic fast passage pulses

    International Nuclear Information System (INIS)

    Zweckstetter, Markus; Holak, Tad A.

    1999-01-01

    We show that adiabatic fast passage (AFP) pulses are robust refocusing elements of transverse 13 C magnetization in multidimensional NMR experiments. A pair of identical AFP pulses can refocus selected parts or a complete 13 C chemical shift range in 13 C spectra. In the constant time 13 C- 1 H HSQC, replacement of attenuated rectangular pulses by selective AFP pulses results in a sensitivity enhancement of up to a factor of 1.8. In the 3D CBCA(CO)NH the signal-to-noise ratio is increased by a factor of up to 1.6

  5. Improved labeling strategy for 13C relaxation measurements of methyl groups in proteins

    International Nuclear Information System (INIS)

    Lee, Andrew L.; Urbauer, Jeffrey L.; Wand, A. Joshua

    1997-01-01

    Selective incorporation of 13 C into the methyl groups of protein side chains is described as a means for simplifying the measurement and interpretation of 13 C relaxation parameters.High incorporation (>90%) is accomplished by using pyruvate(3- 13 C, 99%) as the sole carbon source in the growth media for protein overexpression in E. coli. This improved labeling scheme increases the sensitivity of the relaxation experiments by approximately fivefold when compared to randomly fractionally 13 C-labeled protein, allowing high-quality measurements on relatively dilute (<1 mM)protein samples at a relatively low cost

  6. Ecosystem differences in the trophic enrichment of 13C in aquatic food webs

    International Nuclear Information System (INIS)

    France, R.L.; Peters, R.H.

    1997-01-01

    Data from 35 published studies were collated to examine patterns in the trophic enrichment of 13 C of consumers. Because both δ 13 C and δ 14 N vary systematically across ecosystems, it was necessary to standardize for such differences before combining data from numerous sources. Relationships of these measures of ecosystem-standardized δ 13 C to ecosystem-standardized trophic position (Δδ 15 N) for freshwater, estuarine, coastal, and open-ocean and for all aquatic ecosystems yielded regression equations of low predictive capability (average of 20% explained variance in δ 13 C). However, differences were observed in the slopes between δ 13 C and standardized trophic position when data were examined study-specifically: the average trophic fractionation of 13 C was found to increase from +0.2micron for freshwater to +0.5micron for estuarine to +0.8micron for coastal, and to +1.1micron for open-ocean food webs. This ecosystem-specific gradient in 13 C enrichment for consumers supports previous findings of a similar continuum existing for zooplankton - particulate organic matter differences in δ 13 C. Possible mechanisms to explain these ecosystem-specific patterns in 13 C enrichment may be related to the relative importance of detritus, heterotrophic respiration, partial reliance on alternative food sources, and lipid influences in the different ecosystems. (author)

  7. pH-Dependent spin state population and 19F NMR chemical shift via remote ligand protonation in an iron(ii) complex.

    Science.gov (United States)

    Gaudette, Alexandra I; Thorarinsdottir, Agnes E; Harris, T David

    2017-11-30

    An Fe II complex that features a pH-dependent spin state population, by virtue of a variable ligand protonation state, is described. This behavior leads to a highly pH-dependent 19 F NMR chemical shift with a sensitivity of 13.9(5) ppm per pH unit at 37 °C, thereby demonstrating the potential utility of the complex as a 19 F chemical shift-based pH sensor.

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

    Science.gov (United States)

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

    2017-07-21

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

  9. Metabolic Imaging of Patients with Prostate Cancer Using Hyperpolarized [1-13C]Pyruvate

    Science.gov (United States)

    Nelson, Sarah J.; Kurhanewicz, John; Vigneron, Daniel B.; Larson, Peder E. Z.; Harzstark, Andrea L.; Ferrone, Marcus; van Criekinge, Mark; Chang, Jose W.; Bok, Robert; Park, Ilwoo; Reed, Galen; Carvajal, Lucas; Small, Eric J.; Munster, Pamela; Weinberg, Vivian K.; Ardenkjaer-Larsen, Jan Henrik; Chen, Albert P.; Hurd, Ralph E.; Odegardstuen, Liv-Ingrid; Robb, Fraser J.; Tropp, James; Murray, Jonathan A.

    2014-01-01

    This first-in-man imaging study evaluated the safety and feasibility of hyperpolarized [1-13C]pyruvate as an agent for noninvasively characterizing alterations in tumor metabolism for patients with prostate cancer. Imaging living systems with hyperpolarized agents can result in more than 10,000-fold enhancement in signal relative to conventional magnetic resonance (MR) imaging. When combined with the rapid acquisition of in vivo 13C MR data, it is possible to evaluate the distribution of agents such as [1-13C]pyruvate and its metabolic products lactate, alanine, and bicarbonate in a matter of seconds. Preclinical studies in cancer models have detected elevated levels of hyperpolarized [1-13C]lactate in tumor, with the ratio of [1-13C]lactate/[1-13C]pyruvate being increased in high-grade tumors and decreased after successful treatment. Translation of this technology into humans was achieved by modifying the instrument that generates the hyperpolarized agent, constructing specialized radio frequency coils to detect 13C nuclei, and developing new pulse sequences to efficiently capture the signal. The study population comprised patients with biopsy-proven prostate cancer, with 31 subjects being injected with hyperpolarized [1-13C]pyruvate. The median time to deliver the agent was 66 s, and uptake was observed about 20 s after injection. No dose-limiting toxicities were observed, and the highest dose (0.43 ml/kg of 230 mM agent) gave the best signal-to-noise ratio for hyperpolarized [1-13C]pyruvate. The results were extremely promising in not only confirming the safety of the agent but also showing elevated [1-13C]lactate/[1-13C]pyruvate in regions of biopsy-proven cancer. These findings will be valuable for noninvasive cancer diagnosis and treatment monitoring in future clinical trials. PMID:23946197

  10. Identification of degradation routes of metamitron in soil microcosms using 13C-isotope labeling.

    Science.gov (United States)

    Wang, Shizong; Miltner, Anja; Nowak, Karolina M

    2017-01-01

    Metamitron is one of the most commonly used herbicide in sugar beet and flower bulb cultures. Numerous laboratory and field studies on sorption and degradation of metamitron were performed. Detailed biodegradation studies in soil using 13 C-isotope labeling are still missing. Therefore, we aimed at providing a detailed turnover mass balance of 13 C 6 -metamitron in soil microcosms over 80 days. In the biotic system, metamitron mineralized rapidly, and 13 CO 2 finally constituted 60% of the initial 13 C 6 -metamitron equivalents. In abiotic control experiments CO 2 rose to only 7.4% of the initial 13 C 6 -metamitron equivalents. The 13 C label from 13 C 6 -metamitron was incorporated into microbial amino acids that were ultimately stabilized in the soil organic matter forming presumably harmless biogenic residues. Finally, 13 C label from 13 C 6 -metamitron was distributed between the 13 CO 2 and the 13 C-biogenic residues indicating nearly complete biodegradation. The parallel increase of 13 C-alanine, 13 C-glutamate and 13 CO 2 indicates that metamitron was initially biodegraded via the desamino-metamitron route suggesting its relevance in the growth metabolism. In later phases of biodegradation, the "Rhodococcus route" was indicated by the low 13 CO 2 evolution and the high relevance of the pyruvate pathway, which aims at biomolecule synthesis and seems to be related to starvation. This is a first report on the detailed degradation route of metamitron in soil. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. 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.

  12. 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.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    conformation and properties of the dissolution media such as buffer composition, solution pH, temperature and magnetic field. We have measured the magnetic field dependence of the spin–lattice relaxation time of hyperpolarized [1-13C]pyruvate using field-cycled relaxometry. [1-13C]pyruvate was hyperpolarized...

  14. 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

  15. 1H, 15N and 13C NMR Assignments of Mouse Methionine Sulfoxide Reductase B2

    Science.gov (United States)

    Breivik, Åshild S.; Aachmann, Finn L.; Sal, Lena S.; Kim, Hwa-Young; Del Conte, Rebecca; Gladyshev, Vadim N.; Dikiy, Alexander

    2011-01-01

    A recombinant mouse methionine-r-sulfoxide reductase 2 (MsrB2ΔS) isotopically labeled with 15N and 15N/13C was generated. We report here the 1H, 15N and 13C NMR assignments of the reduced form of this protein. PMID:19636904

  16. 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.

  17. 13C NMR for the assessment of human brain glucose metabolism in vivo

    International Nuclear Information System (INIS)

    Beckman, N.; Seelig, J.; Turkalj, I.; Keller, U.

    1991-01-01

    Proton-decoupled 13 C NMR spectra of the human head were obtained during hyperglycemic glucose clamping using intravenous infusions of [1- 13 C]glucose in normal volunteers. In addition to 13 C signals of mobile lipids, a variety of new metabolite resonances could be resolved for the first time in the human brain. At an enrichment level of 20% [1- 13 C]glucose, the signals of α- and β-glucose at 92.7 and 96.6 ppm, respectively, could be detected in the human brain after only an infusion period of 15 minutes. The spatial localization of the different regions of interest was confirmed by 13 C NMR spectroscopic imaging with a time resolution of 9 minutes. Increasing the enrichment level to 99% [1- 13 C]glucose not only improved the time resolution but allowed the detection of metabolic breakdown products of [1- 13 C]glucose. The time course of 13 C label incorporation into the C 2 , C 3 , and C 4 resonances of glutamate/glutamine and into lactate could be recorded in the human brain. These results suggest the possibility of obtaining time-resolved, spatially selective, and chemically specific information on the human body

  18. 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)

  19. Biosynthetic studies of the glycopeptide teicoplanin by 1H and 13C NMR

    DEFF Research Database (Denmark)

    Heydorn, Arne; Petersen, Bent O.; Duus, Jens Øllgaard

    2000-01-01

    The biosynthesis of the glycopeptide antibiotic teicoplanin was studied by growing a teicoplanin producing strain of Actinoplanes teichomyceticus (ATCC 31121) on glucose containing either 34.0% [1-13C]glucose or 9.7% [U- 13C]glucose. The fractional enrichment pattern of teicoplanin produced in th...

  20. Sensitivity-enhanced 13C MR spectroscopy of the human brain at 3 Tesla.

    NARCIS (Netherlands)

    Klomp, D.W.J.; Renema, W.K.J.; Graaf, M. de; Galan, B.E. de; Kentgens, A.P.M.; Heerschap, A.

    2006-01-01

    A new coil design for sensitivity-enhanced 13C MR spectroscopy (MRS) of the human brain is presented. The design includes a quadrature transmit/receive head coil optimized for 13C MR sensitivity. Loss-less blocking circuits inside the coil conductors allow this coil to be used inside a homogeneous

  1. Intracellular PHB conversion in a type II methanotroph studied by 13 C NMR

    NARCIS (Netherlands)

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

    2001-01-01

    Poly-g-hydroxybutyrate (PHB) formation under aerobic conditions via incorporation of [13C-2]acetate as a cosubstrate and its intracellular degradation under anaerobic conditions in a Type II methanotroph was studied by 13C NMR. During PHB synthesis in the presence of labelled acetate, low levels of

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    Deuterium isotope effects on 13C-NMR chemical shifts are investigated in a series of 10-hydroxybenzo[h]quinolines (HBQ’s) The OH proton is deuteriated. The isotope effects on 13C chemical shifts in these hydrogen bonded systems are rather unusual. The formal four-bond effects are found to be nega...

  3. 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.

  4. 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.

  5. 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)

  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. Overexpression of a homogeneous oligosaccharide with {sup 13}C labeling by genetically engineered yeast strain

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Yukiko; Yamamoto, Sayoko [National Institutes of Natural Sciences, Okazaki Institute for Integrative Bioscience and Institute for Molecular Science (Japan); Chiba, Yasunori; Jigami, Yoshifumi [National Institute of Advanced Industrial Science and Technology, Research Center for Medical Glycoscience (Japan); Kato, Koichi, E-mail: kkatonmr@ims.ac.jp [National Institutes of Natural Sciences, Okazaki Institute for Integrative Bioscience and Institute for Molecular Science (Japan)

    2011-08-15

    This report describes a novel method for overexpression of {sup 13}C-labeled oligosaccharides using genetically engineered Saccharomyces cerevisiae cells, in which a homogeneous high-mannose-type oligosaccharide accumulates because of deletions of genes encoding three enzymes involved in the processing pathway of asparagine-linked oligosaccharides in the Golgi complex. Using uniformly {sup 13}C-labeled glucose as the sole carbon source in the culture medium of these engineered yeast cells, high yields of the isotopically labeled Man{sub 8}GlcNAc{sub 2} oligosaccharide could be successfully harvested from glycoprotein extracts of the cells. Furthermore, {sup 13}C labeling at selected positions of the sugar residues in the oligosaccharide could be achieved using a site-specific {sup 13}C-enriched glucose as the metabolic precursor, facilitating NMR spectral assignments. The {sup 13}C-labeling method presented provides the technical basis for NMR analyses of structures, dynamics, and interactions of larger, branched oligosaccharides.

  8. Synthesis of (+-)-[1,1'-15N2, 2'-13C]-trans-3'-methylnicotine

    International Nuclear Information System (INIS)

    Sirimanne, S.R.; Maggio, V.L.; Patterson, D.G. Jr.

    1992-01-01

    The synthesis of (±)- [1,1'- 15 N 2 , 2'- 13 C]-trans-3'-methylnicotine is reported. 15 N-3-Bromopyridine obtained from bromination of pyridine was formylated with nBuLi/[carbonyl- 13 C]-methyl formate. The resulting 15 n-Pyridine-3-[ 13 C-carbonyl]-carboxaldehyde was reacted with 15 N-methylamine and then the resulting Schiff's base was condensed with succinic anhydride to give (±)- [1,1'- 15 N 2 , 5'- 13 C]-trans-4'-carboxycotinine. Reduction with lithium aluminum hydride and mesylation followed by reduction with Zn/NaI gave (±)-[1,1'- 15 N 2 , 2'- 13 C]-trans-3'-methylnicotine. (Author)

  9. Synthesis of [sup 13]C warfarin labelled at the hemiketal carbon, and its resolution

    Energy Technology Data Exchange (ETDEWEB)

    Savell, V.H. Jr.; Valente, E.J. (Mississippi College, Clinton. MS (United States). Dept. of Chemistry); Eggleston, D.S. (Smith, Kline and French Labs., King of Prussia, PA (United States). Physical and Structural Chemistry)

    1989-06-01

    Warfarin (cyclic hemiketal form: 2-hydroxy-2-methyl-4-phenyl-3,4-dihydro-2H,5H-pyrano[3,2-c][1]benz opyran-5-one) is labeled with 98+% [sup 13]C at the anomeric carbon (C2) and resolved into its enantiomers. Acetone-2-[sup 13]C(98.6%) condenses with benzaldehyde in aqueous base to produce 4-phenyl-3-buten-2-one-2-[sup 13]C(98+%). Michael-type addition of this to 4-hydroxycoumarin in methanol produces the labeled diastereomeric warfarin methyl ketals which on deprotection form racemic warfarin-2-[sup 13]C(98+%). Classical resolution of labeled warfarin with quinidine produces partly resolved (S)-(-)-warfarin-2-[sup 13]C(98+%). Labeled warfarin is a suitable probe for warfarin configuration for which three distinct isomeric forms are known. (Author).

  10. Synthesis of 13C warfarin labelled at the hemiketal carbon, and its resolution

    International Nuclear Information System (INIS)

    Savell, V.H. Jr.; Valente, E.J.; Eggleston, D.S.

    1989-01-01

    Warfarin (cyclic hemiketal form: 2-hydroxy-2-methyl-4-phenyl-3,4-dihydro-2H,5H-pyrano[3,2-c][1]benz opyran-5-one) is labeled with 98+% 13 C at the anomeric carbon (C2) and resolved into its enantiomers. Acetone-2- 13 C(98.6%) condenses with benzaldehyde in aqueous base to produce 4-phenyl-3-buten-2-one-2- 13 C(98+%). Michael-type addition of this to 4-hydroxycoumarin in methanol produces the labeled diastereomeric warfarin methyl ketals which on deprotection form racemic warfarin-2- 13 C(98+%). Classical resolution of labeled warfarin with quinidine produces partly resolved (S)-(-)-warfarin-2- 13 C(98+%). Labeled warfarin is a suitable probe for warfarin configuration for which three distinct isomeric forms are known. (Author)

  11. Fission excitation function for 19F + 194,196,198Pt at near and above barrier energies

    Directory of Open Access Journals (Sweden)

    Singh Varinderjit

    2015-01-01

    Full Text Available Fission excitation functions for 19F + 194,196,198Pt reactions populating 213,215,217Fr compound nuclei are reported. Out of these three compound nuclei, 213Fr is a shell closed (N=126 compound nucleus and the other two are away from the shell closure. From a comparison of the experimental fission cross-sections with the statistical model predictions, it is observed that the fission cross-sections are underestimated by the statistical model predictions using shell corrected finite range rotating liquid drop model (FRLDM fission barriers. Further the FRLDM fission barriers are reduced to fit the fission cross-sections over the entire measured energy range.

  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. 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.

  14. New Improved Indirect Measurement of the {sup 19}F( p , α ){sup 16}O Reaction at Energies of Astrophysical Relevance

    Energy Technology Data Exchange (ETDEWEB)

    Indelicato, I.; La Cognata, M.; Spitaleri, C.; Cherubini, S.; Gulino, M.; Lamia, L.; Pizzone, R. G.; Romano, S.; Tumino, A. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Burjan, V.; Hons, Z.; Kroha, V.; Mrazek, J. [Nuclear Physics Institute of ASCR, Rez near Prague (Czech Republic); Hayakawa, S. [RIKEN, CNS, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Mazzocco, M.; Strano, E.; Torresi, D., E-mail: indelicato@lns.infn.it [INFN, Sezione di Padova, Padova (Italy)

    2017-08-10

    Fluorine abundance determination is of great importance in stellar physics to understand s-elements production and mixing processes in asymptotic giant branch (AGB) stars. Up to now, theoretical models overproduce F abundances in AGB stars with respect to the observed values, thus calling for further investigation of the reactions involving fluorine. In particular, the {sup 19}F( p , α ){sup 16}O reaction is the main destruction channel of fluorine at the bottom of the convective envelope in AGB stars, an H-rich environment where it can experience temperatures high enough to determine its destruction, owing to additional mixing processes. In this paper the Trojan horse method (THM) was used to extract the {sup 19}F( p , α {sub 0}){sup 16}O S-factor in the energy range of astrophysical interest ( E {sub cm} ≈ 0–1 MeV). This is the most relevant channel at the low temperatures (few 10{sup 7} K) characterizing the bottom of the convective envelope, according to current knowledge. A previous indirect experiment using the THM has observed three resonances in the energy regions below E {sub cm} ≈ 450 keV. These energies correspond to typical AGB temperatures, thus implying a significant increase in the reaction rate. Statistics are scarce for performing an accurate separation between resonances, preventing one from drawing a quantitative conclusion about their total widths and spin parities. Before THM measurement, only extrapolations were available below about 500 keV, showing a non-resonant behavior that sharply contradicts the trend of the astrophysical factor at higher energies. A new experiment has been performed to verify the measured TH astrophysical factor and to perform more accurate spectroscopy of the involved resonances.

  15. NbF{sub 5} and TaF{sub 5}: Assignment of {sup 19}F NMR resonances and chemical bond analysis from GIPAW calculations

    Energy Technology Data Exchange (ETDEWEB)

    Biswal, Mamata, E-mail: Mamata.Biswal-Susanta_Kumar_Nayak.Etu@univ-lemans.fr [LUNAM Université, Université du Maine, CNRS UMR 6283, Institut des Molécules et des Matériaux du Mans, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9 (France); Body, Monique, E-mail: monique.body@univ-lemans.fr [LUNAM Université, Université du Maine, CNRS UMR 6283, Institut des Molécules et des Matériaux du Mans, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9 (France); Legein, Christophe, E-mail: christophe.legein@univ-lemans.fr [LUNAM Université, Université du Maine, CNRS UMR 6283, Institut des Molécules et des Matériaux du Mans, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9 (France); Sadoc, Aymeric, E-mail: Aymeric.Sadoc@cnrs-imn.fr [Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Boucher, Florent, E-mail: Florent.Boucher@cnrs-imn.fr [Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France)

    2013-11-15

    The {sup 19}F isotropic chemical shifts (δ{sub iso}) of two isomorphic compounds, NbF{sub 5} and TaF{sub 5}, which involve six nonequivalent fluorine sites, have been experimentally determined from the reconstruction of 1D {sup 19}F MAS NMR spectra. In parallel, the corresponding {sup 19}F chemical shielding tensors have been calculated using the GIPAW method for both experimental and DFT-optimized structures. Furthermore, the [M{sub 4}F{sub 20}] units of NbF{sub 5} and TaF{sub 5} being held together by van der Waals interactions, the relevance of Grimme corrections to the DFT optimization processes has been evaluated. However, the semi-empirical dispersion correction term introduced by such a method does not show any significant improvement. Nonetheless, a complete and convincing assignment of the {sup 19}F NMR lines of NbF{sub 5} and TaF{sub 5} is obtained, ensured by the linearity between experimental {sup 19}F δ{sub iso} values and calculated {sup 19}F isotropic chemical shielding σ{sub iso} values. The effects of the geometry optimizations have been carefully analyzed, confirming among other matters, the inaccuracy of the experimental structure of NbF{sub 5}. The relationships between the fluorine chemical shifts, the nature of the fluorine atoms (bridging or terminal), the position of the terminal ones (opposite or perpendicular to the bridging ones), the fluorine charges, the ionicity and the length of the M–F bonds have been established. Additionally, for three of the {sup 19}F NMR lines of NbF{sub 5}, distorted multiplets, arising from {sup 1}J-coupling and residual dipolar coupling between the {sup 19}F and {sup 93}Nb nuclei, were simulated yielding to values of {sup 93}Nb–{sup 19}F {sup 1}J-coupling for the corresponding fluorine sites. - Graphical abstract: The complete assignment of the {sup 19}F NMR lines of NbF{sub 5} and TaF{sub 5} allow establishing relationships between the {sup 19}F δ{sub iso} values, the nature of the fluorine atoms

  16. (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

  17. (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.

  18. Determination of the Orientation and Dynamics of Ergosterol in Model Membranes Using Uniform 13C Labeling and Dynamically Averaged 13C Chemical Shift Anisotropies as Experimental Restraints

    Science.gov (United States)

    Soubias, O.; Jolibois, F.; Massou, S.; Milon, A.; Réat, V.

    2005-01-01

    A new strategy was established to determine the average orientation and dynamics of ergosterol in dimyristoylphosphatidylcholine model membranes. It is based on the analysis of chemical shift anisotropies (CSAs) averaged by the molecular dynamics. Static 13C CSA tensors were computed by quantum chemistry, using the gauge-including atomic-orbital approach within Hartree-Fock theory. Uniformly 13C-labeled ergosterol was purified from Pichia pastoris cells grown on labeled methanol. After reconstitution into dimyristoylphosphatidylcholine lipids, the complete 1H and 13C assignment of ergosterol's resonances was performed using a combination of magic-angle spinning two-dimensional experiments. Dynamically averaged CSAs were determined by standard side-band intensity analysis for isolated 13C resonances (C3 and ethylenic carbons) and by off-magic-angle spinning experiments for other carbons. A set of 18 constraints was thus obtained, from which the sterol's molecular order parameter and average orientation could be precisely defined. The validity of using computed CSAs in this strategy was verified on cholesterol model systems. This new method allowed us to quantify ergosterol's dynamics at three molar ratios: 16 mol % (Ld phase), 30 mol % (Lo phase), and 23 mol % (mixed phases). Contrary to cholesterol, ergosterol's molecular diffusion axis makes an important angle (14°) with the inertial axis of the rigid four-ring system. PMID:15923221

  19. Two new organic reference materials for δ13C and δ15N measurements and a new value for the δ13C of NBS 22 oil

    Science.gov (United States)

    Qi, Haiping; Coplen, Tyler B.; Geilmann, Heike; Brand, Willi A.; Böhlke, J.K.

    2003-01-01

    Analytical grade L-glutamic acid is chemically stable and has a C/N mole ratio of 5, which is close to that of many of natural biological materials, such as blood and animal tissue. Two L-glutamic acid reference materials with substantially different 13C and 15N abundances have been prepared for use as organic reference materials for C and N isotopic measurements. USGS40 is analytical grade L-glutamic acid and has a δ13C value of −26.24‰ relative to VPDB and a δ15N value of −4.52‰ relative to N2 in air. USGS41 was prepared by dissolving analytical grade L-glutamic acid with L-glutamic acid enriched in 13C and 15N. USGS41 has a δ13C value of +37.76‰ and a δ15N value of +47.57‰. The δ13C and δ15N values of both materials were measured against the international reference materials NBS 19 calcium carbonate (δ13C = +1.95‰), L-SVEC lithium carbonate (δ13C = −46.48‰), IAEA-N-1 ammonium sulfate (δ15N = 0.43‰), and USGS32 potassium nitrate (δ15N = 180‰) by on-line combustion continuous-flow and off-line dual-inlet isotope-ratio mass spectrometry. Both USGS40 and USGS41 are isotopically homogeneous; reproducibility of δ13C is better than 0.13‰, and that of δ15N is better than 0.13‰ in 100-μg amounts. These two isotopic reference materials can be used for (i) calibrating local laboratory reference materials, and (ii) quantifying drift with time, mass-dependent fractionations, and isotope-ratio-scale contraction in the isotopic analysis of various biological materials. Isotopic results presented in this paper yield a δ13C value for NBS 22 oil of −29.91‰, in contrast to the commonly accepted value of −29.78‰ for which off-line blank corrections probably have not been quantified satisfactorily.

  20. 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

  1. 13C/12C ratio variations in Pinus longaeva (bristlecone pine) cellulose during the last millennium

    International Nuclear Information System (INIS)

    Grinsted, M.J.; Wilson, A.T.; Ferguson, C.W.

    1979-01-01

    Delta 13 C values are presented for cellulose samples prepared from two dendrochronologically dated Pinus longaeva (bristlecone pine) trees which grew during the last 1000 years. Delta 13 C variations for these forest border trees are similar to upper tree line ring-width variations for the same species and English high summer temperature variations for the same time period. However, the delta 13 C variations appear to be unrelated to lower forest border ring-width variations and cellulose deltaD variations for the same specimens. (Auth.)

  2. 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).

  3. Stable Carbon Isotopes (δ 13C) in Coral Skeletons: Experimental Approach and Applications for Paleoceanography

    Science.gov (United States)

    Grottoli, A. G.

    2004-12-01

    Scleractinian corals obtain fixed carbon via photosynthesis by their endosymbiotic algae (zooxanthellae) and via hetertrophy (injestion of zooplankton, δ 13C ≈ -17 to -22‰ ). Carbon dioxide (CO2) used for photosynthesis is obtained from seawater (δ 13C ≈ 0%) or from respired CO2 within the coral host. The δ 13C of the carbon used in the formation of the underlying coral skeleton is fractionated as a result of both of these metabolic processes. Here I have pooled evidence from several field and tank experiments on the effect of photosynthesis and heterotrophy of coral skeletal δ 13C. In the experiments, decreases in light levels due to shading or depth resulted in a significant decrease in skeletal δ 13C in all species studied (Pavona gigantea, Pavona clavus, Porites compressa). Decreases in photosynthesis in bleached corals also resulted in a decrease in skeletal δ 13C compared to non-bleached corals growing under the same conditions and at the same location. Skeletal δ 13C also decreased at higher than normal light levels most likely due to photoinhibition. Thus, decreases in photosynthesis due to reduced light levels, due to bleaching-induced decreases in chlorophyll a concentrations, or due to photodamage-induced decreases in functional cholorphyll a, results in significant δ 13C decreases. Comprehensive interpretation of all of the data showed that changes in photosynthesis itself can drive the changes in δ 13C. In field experiments, the addition of natural concentrations of zooplankton to the diet resulted in decreases in skeletal δ 13C. Such a decrease was more pronounced with depth and in P. gigantea compared to P. clavus. In situ feeding experiments have since confirmed these findings. However under tank conditions with unaturally high feeding rates, enhanced nitrogen supply in the diet can disrupt the coral-algal symbiosis, stimlate zooxanthellae growth and photosynthesis, and cause an incrase in skeletal δ 13C. It is proposed that under

  4. 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)

  5. Authentication of the origin of vanillin using quantitative natural abundance 13C NMR.

    Science.gov (United States)

    Tenailleau, Eve J; Lancelin, Pierre; Robins, Richard J; Akoka, Serge

    2004-12-29

    The use of 13C isotopic distribution as an efficient means to determine the origin of vanillin has been substantiated. Using quantitative 13C NMR, the 13C/12C ratios at all eight carbon positions can be exploited. On a set of 21 samples of vanillin from five different origins, complete discrimination can be achieved. It is shown that, for many purposes, a rapid analysis in which only five sites are used is sufficient. However, improved discrimination using all eight sites is preferable to differentiate between different methods of production from natural ferulic acid or between natural and lignin-derived vanillin on the basis of the 13C/12C ratios characteristic of different origins. The C1 and C8 positions are demonstrated to be the most significant sites for discrimination using principle component analysis. However, aromatic carbon positions make an essential contribution, notably in differentiating between natural and lignin-derived vanillin.

  6. Speculations about the upper Miocene change in abyssal Pacific dissolved bicarbonate delta13C

    International Nuclear Information System (INIS)

    Bender, M.L.; Keigwin, L.D. Jr

    1979-01-01

    New data from three Tasman Sea cores support Kleigwin's observation that the delta 13 C of Pacific benthic foraminifera (and by inference bottom-water TCO 2 ) decreased by 0.7 per thousand at about 6.5 Myr B.P. Simple box models are developed and used to test several hypotheses about the cause of the delta 13 C decrease. The authors favor the idea that the delta 13 C shift was due to a rapid change in TCO 2 cycling within the oceans (such as would result from either a decrease in upwelling rate, or an increase in the fraction of PO 4 3- reaching the deep oceans in particulate organic matter and a corresponding drop in the performed PO 4 3- concentration). The delta 13 C decrease across the shift might reflect either a global decrease in upwelling rate, or a different abyssal circulation pattern before the shift. (Auth.)

  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. 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)

  9. Verification of threshold activation detection (TAD) technique in prompt fission neutron detection using scintillators containing 19F

    Science.gov (United States)

    Sibczynski, P.; Kownacki, J.; Moszyński, M.; Iwanowska-Hanke, J.; Syntfeld-Każuch, A.; Gójska, A.; Gierlik, M.; Kaźmierczak, Ł.; Jakubowska, E.; Kędzierski, G.; Kujawiński, Ł.; Wojnarowicz, J.; Carrel, F.; Ledieu, M.; Lainé, F.

    2015-09-01

    In the present study ⌀ 5''× 3'' and ⌀ 2''× 2'' EJ-313 liquid fluorocarbon as well as ⌀ 2'' × 3'' BaF2 scintillators were exposed to neutrons from a 252Cf neutron source and a Sodern Genie 16GT deuterium-tritium (D+T) neutron generator. The scintillators responses to β- particles with maximum endpoint energy of 10.4 MeV from the n+19F reactions were studied. Response of a ⌀ 5'' × 3'' BC-408 plastic scintillator was also studied as a reference. The β- particles are the products of interaction of fast neutrons with 19F which is a component of the EJ-313 and BaF2 scintillators. The method of fast neutron detection via fluorine activation is already known as Threshold Activation Detection (TAD) and was proposed for photofission prompt neutron detection from fissionable and Special Nuclear Materials (SNM) in the field of Homeland Security and Border Monitoring. Measurements of the number of counts between 6.0 and 10.5 MeV with a 252Cf source showed that the relative neutron detection efficiency ratio, defined as epsilonBaF2 / epsilonEJ-313-5'', is 32.0% ± 2.3% and 44.6% ± 3.4% for front-on and side-on orientation of the BaF2, respectively. Moreover, the ⌀ 5'' EJ-313 and side-on oriented BaF2 were also exposed to neutrons from the D+T neutron generator, and the relative efficiency epsilonBaF2 / epsilonEJ-313-5'' was estimated to be 39.3%. Measurements of prompt photofission neutrons with the BaF2 detector by means of data acquisition after irradiation (out-of-beam) of nuclear material and between the beam pulses (beam-off) techniques were also conducted on the 9 MeV LINAC of the SAPHIR facility.

  10. Direct 19F NMR observation of the conformational selection of optically active rotamers of the antifolate compound fluoronitropyrimethamine bound to enzyme dihydrofolate reductase

    International Nuclear Information System (INIS)

    Tendler, S.J.B.; Birdsall, B.; Feeney, J.; Griffin, R.J.; Stevens, M.F.G.; Roberts, G.C.K.

    1988-01-01

    The molucular basis of the binding of the lipophilic antifolate compound fluoronitropyrimethamine to its target enzyme dihydrofolate reductase has been investigated using a combination of 19 F NMR spectroscopy and molecular mechanical calculations 19 F NMR reveals the presence of two different conformational states for the fluoronitropyrimethamine-Lactobacillus casei enzyme complex. MM2 molecular mechanical calculations predict restricted rotation about the C5-C1 bond of the ligand and this give rise to two slowly interconverting rotamers which are an enantiomeric pair. The results of 19 F NMR spectroscopy reveal that both these isomers bind to the enzyme, with different affinities. There is no detectable interconversion of the bound rotamers themselves on the NMR timescale. The effect of the addition of co-enzyme to the sample is to reverse the preference the enzyme has for each rotamer. (author). 11 refs.; 3 figs

  11. Direct visualization of in vitro drug mobilization from Lescol XL tablets using two-dimensional (19)F and (1)H magnetic resonance imaging.

    Science.gov (United States)

    Chen, Chen; Gladden, Lynn F; Mantle, Michael D

    2014-02-03

    This article reports the application of in vitro multinuclear ((19)F and (1)H) two-dimensional magnetic resonance imaging (MRI) to study both dissolution media ingress and drug egress from a commercial Lescol XL extended release tablet in a United States Pharmacopeia Type IV (USP-IV) dissolution cell under pharmacopoeial conditions. Noninvasive spatial maps of tablet swelling and dissolution, as well as the mobilization and distribution of the drug are quantified and visualized. Two-dimensional active pharmaceutical ingredient (API) mobilization and distribution maps were obtained via (19)F MRI. (19)F API maps were coregistered with (1)H T2-relaxation time maps enabling the simultaneous visualization of drug distribution and gel layer dynamics within the swollen tablet. The behavior of the MRI data is also discussed in terms of its relationship to the UV drug release behavior.

  12. A procedure to validate and correct the {sup 13}C chemical shift calibration of RNA datasets

    Energy Technology Data Exchange (ETDEWEB)

    Aeschbacher, Thomas; Schubert, Mario, E-mail: schubert@mol.biol.ethz.ch; Allain, Frederic H.-T., E-mail: allain@mol.biol.ethz.ch [ETH Zuerich, Institute for Molecular Biology and Biophysics (Switzerland)

    2012-02-15

    Chemical shifts reflect the structural environment of a certain nucleus and can be used to extract structural and dynamic information. Proper calibration is indispensable to extract such information from chemical shifts. Whereas a variety of procedures exist to verify the chemical shift calibration for proteins, no such procedure is available for RNAs to date. We present here a procedure to analyze and correct the calibration of {sup 13}C NMR data of RNAs. Our procedure uses five {sup 13}C chemical shifts as a reference, each of them found in a narrow shift range in most datasets deposited in the Biological Magnetic Resonance Bank. In 49 datasets we could evaluate the {sup 13}C calibration and detect errors or inconsistencies in RNA {sup 13}C chemical shifts based on these chemical shift reference values. More than half of the datasets (27 out of those 49) were found to be improperly referenced or contained inconsistencies. This large inconsistency rate possibly explains that no clear structure-{sup 13}C chemical shift relationship has emerged for RNA so far. We were able to recalibrate or correct 17 datasets resulting in 39 usable {sup 13}C datasets. 6 new datasets from our lab were used to verify our method increasing the database to 45 usable datasets. We can now search for structure-chemical shift relationships with this improved list of {sup 13}C chemical shift data. This is demonstrated by a clear relationship between ribose {sup 13}C shifts and the sugar pucker, which can be used to predict a C2 Prime - or C3 Prime -endo conformation of the ribose with high accuracy. The improved quality of the chemical shift data allows statistical analysis with the potential to facilitate assignment procedures, and the extraction of restraints for structure calculations of RNA.

  13. 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)

  14. 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

  15. Methodology and application of 13C breath test in gastroenterology practice

    International Nuclear Information System (INIS)

    Yan Weili; Jiang Yibin

    2002-01-01

    13 C breath test has been widely used in research of nutrition, pharmacology and gastroenterology for its properties such as safety, non-invasion and so on. The author describes the principle, methodology of 13 C breath test and its application in detection to Helico-bacteria pylori infection in stomach and small bowl bacterial overgrowth, measurement of gastric emptying, pancreatic exocrine function and liver function with various substrates

  16. Search for biological effects of 13C-enrichment in developing mammalian systems

    International Nuclear Information System (INIS)

    Gregg, C.; Ott, D.; Deaven, L.; Spielmann, H.; Krowke, R.; Neubert, D.

    1975-01-01

    Increasing diagnostic use of stable isotopes, especially in children and pregnant women, enhances the importance of studies on the biological isotope effects in sensitive mammalian systems. Experimental data on animal systems are meager. The mouse embryos was studied at various stages and mouse limb buds were studied in organ culture. Limb bud development in vitro was unaffected by incubation with 82 mol percent 13 C-glucose as judged by either morphological or biochemical criteria. Of 271 preimplantation embryos incubated in vitro, 95.2 percent developed normally; in 13 C-enriched medium, 96.5 percent showed normal development. 13 C-Enrichment of the embryos in vitro is over 60 percent. Administration of 1.2 g glucose-U- 13 C to pregnant mice during organogenesis leads to enrichment of maternal liver glycogen to over 17 mol percent 13 C, about one-third this level in the embryo, and a lower level in maternal blood. The absolute 13 C content of the embryo continues to increase for several days after the end of isotope administration, while the enrichment in maternal tissues falls. The lipid fraction of the fetus is most highly labeled shortly after the end of isotope administration []These studies on developing mammalian systems have not yet revealed any alteration of normal development due to stable isotope enrichment. (auth)

  17. Intramolecular 13C analysis of tree rings provides multiple plant ecophysiology signals covering decades.

    Science.gov (United States)

    Wieloch, Thomas; Ehlers, Ina; Yu, Jun; Frank, David; Grabner, Michael; Gessler, Arthur; Schleucher, Jürgen

    2018-03-22

    Measurements of carbon isotope contents of plant organic matter provide important information in diverse fields such as plant breeding, ecophysiology, biogeochemistry and paleoclimatology. They are currently based on 13 C/ 12 C ratios of specific, whole metabolites, but we show here that intramolecular ratios provide higher resolution information. In the glucose units of tree-ring cellulose of 12 tree species, we detected large differences in 13 C/ 12 C ratios (>10‰) among carbon atoms, which provide isotopically distinct inputs to major global C pools, including wood and soil organic matter. Thus, considering position-specific differences can improve characterisation of soil-to-atmosphere carbon fluxes and soil metabolism. In a Pinus nigra tree-ring archive formed from 1961 to 1995, we found novel 13 C signals, and show that intramolecular analysis enables more comprehensive and precise signal extraction from tree rings, and thus higher resolution reconstruction of plants' responses to climate change. Moreover, we propose an ecophysiological mechanism for the introduction of a 13 C signal, which links an environmental shift to the triggered metabolic shift and its intramolecular 13 C signature. In conclusion, intramolecular 13 C analyses can provide valuable new information about long-term metabolic dynamics for numerous applications.

  18. Tumour oxygen dynamics measured simultaneously by near-infrared spectroscopy and 19F magnetic resonance imaging in rats

    International Nuclear Information System (INIS)

    Xia Mengna; Kodibagkar, Vikram; Liu Hanli; Mason, Ralph P

    2006-01-01

    Simultaneous near-infrared spectroscopy (NIRS) and magnetic resonance imaging (MRI) were used to investigate the correlation between tumour vascular oxygenation and tissue oxygen tension dynamics in rat breast 13762NF tumours with respect to hyperoxic gas breathing. NIRS directly detected global variations in the oxygenated haemoglobin concentration (Δ[HbO 2 ]) within tumours and oxygen tension (pO 2 ) maps were achieved using 19 F MRI of the reporter molecule hexafluorobenzene. Multiple correlations were examined between rates and magnitudes of vascular (Δ[HbO 2 ]) and tissue (pO 2 ) responses. Significant correlations were found between response to oxygen and carbogen breathing using either modality. Comparison of results for the two methods showed a correlation between the vascular perfusion rate ratio and the mean pO 2 values (R 2 > 0.7). The initial rates of increase of Δ[HbO 2 ] and the slope of dynamic pO 2 response, d(pO 2 )/dt, of well-oxygenated voxels in response to hyperoxic challenge were also correlated. These results demonstrate the feasibility of simultaneous measurements using NIRS and MRI. As expected, the rate of pO 2 response to oxygen is primarily dependent upon the well perfused rather than poorly perfused vasculature

  19. 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)

  20. 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

  1. Migration and deposition of 13C in the full-tungsten ASDEX Upgrade tokamak

    International Nuclear Information System (INIS)

    Hakola, A; Aho-Mantila, L; Groth, M; Kurki-Suonio, T; Makkonen, T; Likonen, J; Koivuranta, S; Krieger, K; Mayer, M; Mueller, H W; Neu, R; Rohde, V

    2010-01-01

    The migration of carbon in low-density, low-confinement plasmas of ASDEX Upgrade was studied by injecting 13 C into the main chamber of the torus at the end of the 2007 experimental campaign. A selection of standard tungsten-coated lower-divertor and main-chamber tiles as well as a complete set of lower-divertor tiles with an uncoated poloidal marker stripe were removed from one poloidal cross section and analysed using secondary ion mass spectrometry. The poloidal deposition profiles of 13 C on both the tungsten-coated tiles and on the uncoated graphite areas of the marker tiles were measured and compared. For the W-coated lower-divertor tiles, 13 C was deposited mainly on the high-field side tiles, while barely detectable amounts of 13 C were observed on low-field side samples. In contrast, on the uncoated marker stripes the deposition was equally pronounced in the high-field and low-field side divertor. The marker-tile results are in agreement with those obtained from graphite tiles after the 2003 and 2005 13 C experiments in ASDEX Upgrade. In the case of W-coated tiles, the 13 C measurements were complemented by determining the total amount of deposited carbon ( 12 C) on the tiles, which also shows strong deposition at the inner parts of the lower divertor. The estimated deposition of 13 C on W at the divertor areas was less than 1.5% of the injected amount of 13 C atoms. The 13 C analyses of the main-chamber tiles and small silicon samples mounted in remote areas revealed significant deposition in the upper divertor, in upper parts of the heat shield, in the limiter region close to the injection valve, and below the roof baffle. Approximately 8% of the injected 13 C is estimated to have accumulated in these regions. Possible reasons for the different deposition patterns on W and on graphite in different regions of the torus are discussed.

  2. On the use of phloem sap δ13C to estimate canopy carbon discrimination

    Science.gov (United States)

    Rascher, Katherine; Máguas, Cristina; Werner, Christiane

    2010-05-01

    Although the carbon stable isotope composition (d13C) of bulk leaf material is a good integrative parameter of photosynthetic discrimination and can be used as a reliable ecological index of plant functioning; it is not a good tracer of short-term changes in photosynthetic discrimination. In contrast, d13C of phloem sap is potentially useful as an indicator of short-term changes in canopy photosynthetic discrimination. However, recent research indicates that d13C signatures may be substantially altered by metabolic processes downstream of initial leaf-level carbon fixation (e.g. post-photosynthetic fractionation). Accordingly, before phloem sap d13C can be used as a proxy for canopy level carbon discrimination an understanding of factors influencing the degree and magnitude of post-photosynthetic fractionation and how these vary between species is of paramount importance. In this study, we measured the d13C signature along the basipetal transport pathway in two co-occurring tree species in the field - an understory invasive exotic legume, Acacia longifolia, and a native pine, Pinus pinaster. We measured d13C of bulk leaf and leaf water soluble organic matter (WSOM), phloem sap sampled at two points along the plant axis and leaf and root dark respiration. In general, species differences in photosynthetic discrimination resulted in more enriched d13C values in the water-conserving P. pinaster relative to the water-spending A. longifolia. Post-photosynthetic fractionation led to differences in d13C of carbon pools along the plant axis with progressively more depleted d13C from the canopy to the trunk (~6.5 per mil depletion in A. longifolia and ~0.8per mil depletion in P. pinaster). Leaf and root respiration, d13C, were consistently enriched relative to putative substrates. We hypothesize that the pronounced enrichment of leaf respired CO2 relative to leaf WSOM may have left behind relatively depleted carbon to be loaded into the phloem resulting in d13C depletion

  3. Einstein's Symphony: A Gravitational Wave Voyage Through Space and Time

    Science.gov (United States)

    Shapiro Key, Joey; Yunes, Nico; Grimberg, Irene

    2015-01-01

    Einstein's Symphony: A Gravitational Wave Voyage Through Space and Time is a gravitational wave astronomy planetarium show in production by a collaboration of scientists, filmmakers, and artisits from the Center for Gravitational Wave Astonomy (CGWA) at the University of Texas at Brownsville (UTB) and Montana State University (MSU). The project builds on the success of the interdisciplinary Celebrating Einstein collaboration. The artists and scientists who created the A Shout Across Time original film and the Black (W)hole immersive art installation for Celebrating Einstein are teaming with the Museum of the Rockies Taylor Planetarium staff and students to create a new full dome Digistar planetarium show that will be freely and widely distributed to planetaria in the US and abroad. The show uses images and animations filmed and collected for A Shout Across Time and for Black (W)hole as well as new images and animations and a new soundtrack composed and produced by the MSU School of Music to use the full capability of planetarium sound systems. The planetarium show will be narrated with ideas drawn from the Celebrating Einstein danced lecture on gravitational waves that the collaboration produced. The combination of products, resources, and team members assembled for this project allows us to create an original planetarium show for a fraction of the cost of a typical show. In addition, STEM education materials for G6-12 students and teachers will be provided to complement and support the show. This project is supported by the Texas Space Grant Consortium (TSGC), Montana Space Grant Consortium (MSGC), and the American Physical Society (APS).

  4. 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.

  5. A synthesis of marine sediment core δ13C data over the last 150 000 years

    Directory of Open Access Journals (Sweden)

    R. E. M. Rickaby

    2010-10-01

    Full Text Available The isotopic composition of carbon, δ13C, in seawater is used in reconstructions of ocean circulation, marine productivity, air-sea gas exchange, and biosphere carbon storage. Here, a synthesis of δ13C measurements taken from foraminifera in marine sediment cores over the last 150 000 years is presented. The dataset comprises previously published and unpublished data from benthic and planktonic records throughout the global ocean. Data are placed on a common δ18O age scale suitable for examining orbital timescale variability but not millennial events, which are removed by a 10 ka filter. Error estimates account for the resolution and scatter of the original data, and uncertainty in the relationship between δ13C of calcite and of dissolved inorganic carbon (DIC in seawater. This will assist comparison with δ13C of DIC output from models, which can be further improved using model outputs such as temperature, DIC concentration, and alkalinity to improve estimates of fractionation during calcite formation. High global deep ocean δ13C, indicating isotopically heavy carbon, is obtained during Marine Isotope Stages (MIS 1, 3, 5a, c and e, and low δ13C during MIS 2, 4 and 6, which are temperature minima, with larger amplitude variability in the Atlantic Ocean than the Pacific Ocean. This is likely to result from changes in biosphere carbon storage, modulated by changes in ocean circulation, productivity, and air-sea gas exchange. The North Atlantic vertical δ13C gradient is greater during temperature minima than temperature maxima, attributed to changes in the spatial extent of Atlantic source waters. There are insufficient data from shallower than 2500 m to obtain a coherent pattern in other ocean basins. The data synthesis indicates that basin-scale δ13C during the last interglacial (MIS 5e is not clearly distinguishable from the Holocene (MIS 1 or from MIS 5a and 5c, despite significant differences in ice volume and atmospheric CO2

  6. Multi-objective experimental design for (13)C-based metabolic flux analysis.

    Science.gov (United States)

    Bouvin, Jeroen; Cajot, Simon; D'Huys, Pieter-Jan; Ampofo-Asiama, Jerry; Anné, Jozef; Van Impe, Jan; Geeraerd, Annemie; Bernaerts, Kristel

    2015-10-01

    (13)C-based metabolic flux analysis is an excellent technique to resolve fluxes in the central carbon metabolism but costs can be significant when using specialized tracers. This work presents a framework for cost-effective design of (13)C-tracer experiments, illustrated on two different networks. Linear and non-linear optimal input mixtures are computed for networks for Streptomyces lividans and a carcinoma cell line. If only glucose tracers are considered as labeled substrate for a carcinoma cell line or S. lividans, the best parameter estimation accuracy is obtained by mixtures containing high amounts of 1,2-(13)C2 glucose combined with uniformly labeled glucose. Experimental designs are evaluated based on a linear (D-criterion) and non-linear approach (S-criterion). Both approaches generate almost the same input mixture, however, the linear approach is favored due to its low computational effort. The high amount of 1,2-(13)C2 glucose in the optimal designs coincides with a high experimental cost, which is further enhanced when labeling is introduced in glutamine and aspartate tracers. Multi-objective optimization gives the possibility to assess experimental quality and cost at the same time and can reveal excellent compromise experiments. For example, the combination of 100% 1,2-(13)C2 glucose with 100% position one labeled glutamine and the combination of 100% 1,2-(13)C2 glucose with 100% uniformly labeled glutamine perform equally well for the carcinoma cell line, but the first mixture offers a decrease in cost of $ 120 per ml-scale cell culture experiment. We demonstrated the validity of a multi-objective linear approach to perform optimal experimental designs for the non-linear problem of (13)C-metabolic flux analysis. Tools and a workflow are provided to perform multi-objective design. The effortless calculation of the D-criterion can be exploited to perform high-throughput screening of possible (13)C-tracers, while the illustrated benefit of multi

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

    Directory of Open Access Journals (Sweden)

    Corin O. Miller

    2017-06-01

    Full Text Available Introduction: Glycogen is the primary intracellular storage form of carbohydrates. In contrast to most tissues where stored glycogen can only supply the local tissue with energy, hepatic glycogen is mobilized and released into the blood to maintain appropriate circulating glucose levels, and is delivered to other tissues as glucose in response to energetic demands. Insulin and glucagon, two current targets of high interest in the pharmaceutical industry, are well-known glucose-regulating hormones whose primary effect in liver is to modulate glycogen synthesis and breakdown. The purpose of these studies was to develop methods to measure glycogen metabolism in real time non-invasively both in isolated mouse livers, and in non-human primates (NHPs using 13C MRS.Methods: Livers were harvested from C57/Bl6 mice and perfused with [1-13C] Glucose. To demonstrate the ability to measure acute changes in glycogen metabolism ex-vivo, fructose, glucagon, and insulin were administered to the liver ex-vivo. The C1 resonance of glycogen was measured in real time with 13C MRS using an 11.7T (500 MHz NMR spectrometer. To demonstrate the translatability of this approach, NHPs (male rhesus monkeys were studied in a 7 T Philips MRI using a partial volume 1H/13C imaging coil. NPHs were subjected to a variable IV infusion of [1-13C] glucose (to maintain blood glucose at 3-4x basal, along with a constant 1 mg/kg/min infusion of fructose. The C1 resonance of glycogen was again measured in real time with 13C MRS. To demonstrate the ability to measure changes in glycogen metabolism in vivo, animals received a glucagon infusion (1 μg/kg bolus followed by 40 ng/kg/min constant infusion half way through the study on the second study session.Results: In both perfused mouse livers and in NHPs, hepatic 13C-glycogen synthesis (i.e., monotonic increases in the 13C-glycogen NMR signal was readily detected. In both paradigms, addition of glucagon resulted in cessation of glycogen

  8. 13C Mrs Studies of the Control of Hepatic Glycogen Metabolism at High Magnetic Fields

    Science.gov (United States)

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

    2017-06-01

    Introduction: Glycogen is the primary intracellular storage form of carbohydrates. In contrast to most tissues where stored glycogen can only supply the local tissue with energy, hepatic glycogen is mobilized and released into the blood to maintain appropriate circulating glucose levels, and is delivered to other tissues as glucose in response to energetic demands. Insulin and glucagon, two current targets of high interest in the pharmaceutical industry, are well known glucose-regulating hormones whose primary effect in liver is to modulate glycogen synthesis and breakdown. The purpose of these studies was to develop methods to measure glycogen metabolism in real time non-invasively both in isolated mouse livers, and in non-human primates (NHPs) using 13C MRS. Methods: Livers were harvested from C57/Bl6 mice and perfused with [1-13C] Glucose. To demonstrate the ability to measure acute changes in glycogen metabolism ex-vivo, fructose, glucagon, and insulin were administered to the liver ex-vivo. The C1 resonance of glycogen was measured in real time with 13C MRS using an 11.7T (500 MHz) NMR spectrometer. To demonstrate the translatability of this approach, NHPs (male rhesus monkeys) were studied in a 7 T Philips MRI using a partial volume 1H/13C imaging coil. NPHs were subjected to a variable IV infusion of [1-13C] glucose (to maintain blood glucose at 3-4x basal), along with a constant 1 mg/kg/min infusion of fructose. The C1 resonance of glycogen was again measured in real time with 13C MRS. To demonstrate the ability to measure changes in glycogen metabolism in vivo, animals received a glucagon infusion (1 μg/kg bolus followed by 40 ng/kg/min constant infusion) half way through the study on the second study session. Results: In both perfused mouse livers and in NHPs, hepatic 13C-glycogen synthesis (i.e. monotonic increases in the 13C-glycogen NMR signal) was readily detected. In both paradigms, addition of glucagon resulted in cessation of glycogen synthesis

  9. [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.

  10. A Robust Analysis Method For Δ13c Signal Of Bulk Organic Matter In Speleothems

    Science.gov (United States)

    Bian, F.; Blyth, A. J.; Smith, C.; Baker, A.

    2017-12-01

    Speleothems preserve organic matter that is derived from both the surface soil and cave environments. This organic matter can be used to understand paleoclimate and paleoenvironments. However, a stable and quick micro-analysis method to measure the δ13C signals from speleothem organic matter separate from the total δ13C remains absent. And speleothem organic geochemistry is still relatively unexplored compared to inorganic geochemistry. In this research, for the organic matter analysis, bulk homogeneous power samples were obtained from one large stalagmite. These were dissolved by phosphoric acid to produce the aqueous solution. Then, the processed solution was degassed through a rotational vacuum concentrator. A liquid chromatograph was coupled to IRMS to control the oxidization and the measurement of analytes. This method is demonstrated to be robust for the analysis of speleothem d13C organic matter analysis under different preparation and instrumental settings, with the low standard deviation ( 0.2‰), and low sample consumption (<25 mg). Considering the complexity of cave environments, this method will be useful in further investigations the δ13C of entrapped organic matter and environmental controls in other climatic and ecological contexts, including the determination of whether vegetation or soil microbial activity is the dominant control on speleothem d13C of organic matter.

  11. Synthesis of [13C6]-labelled phenethylamine derivatives for drug quantification in biological samples.

    Science.gov (United States)

    Karlsen, Morten; Liu, HuiLing; Berg, Thomas; Johansen, Jon Eigill; Hoff, Bård Helge

    2014-05-15

    The availability of high-quality (13)C-labelled internal standards will improve accurate quantification of narcotics and drugs in biological samples. Thus, the synthesis of 10 [(13)C6]-labelled phenethylamine derivatives, namely amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxy-N-ethylamphetamine, 4-methoxyamphetamine, 4-methoxymethamphetamine, 3,5-dimethoxyphenethylamine 4-bromo-2,5-dimethoxyphenethylamine and 2,5-dimethoxy-4-iodophenethylamine, have been undertaken. [(13)C6]-Phenol proved to be an excellent starting material for making (13)C-labelled narcotic substances in the phenethylamine class, and a developed Stille-type coupling enabled an efficient synthesis of the 3,4-methylenedioxy and 4-methoxy derivatives. The pros and cons of alternative routes and transformations are also discussed. The [(13)C6]-labelled compounds are intended for use as internal standards in forensic analysis, health sciences and metabolomics studies by gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry. Copyright © 2014 John Wiley & Sons, Ltd.

  12. 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

  13. 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.

  14. To be certain about the uncertainty: Bayesian statistics for 13 C metabolic flux analysis.

    Science.gov (United States)

    Theorell, Axel; Leweke, Samuel; Wiechert, Wolfgang; Nöh, Katharina

    2017-11-01

    13 C Metabolic Fluxes Analysis ( 13 C MFA) remains to be the most powerful approach to determine intracellular metabolic reaction rates. Decisions on strain engineering and experimentation heavily rely upon the certainty with which these fluxes are estimated. For uncertainty quantification, the vast majority of 13 C MFA studies relies on confidence intervals from the paradigm of Frequentist statistics. However, it is well known that the confidence intervals for a given experimental outcome are not uniquely defined. As a result, confidence intervals produced by different methods can be different, but nevertheless equally valid. This is of high relevance to 13 C MFA, since practitioners regularly use three different approximate approaches for calculating confidence intervals. By means of a computational study with a realistic model of the central carbon metabolism of E. coli, we provide strong evidence that confidence intervals used in the field depend strongly on the technique with which they were calculated and, thus, their use leads to misinterpretation of the flux uncertainty. In order to provide a better alternative to confidence intervals in 13 C MFA, we demonstrate that credible intervals from the paradigm of Bayesian statistics give more reliable flux uncertainty quantifications which can be readily computed with high accuracy using Markov chain Monte Carlo. In addition, the widely applied chi-square test, as a means of testing whether the model reproduces the data, is examined closer. © 2017 Wiley Periodicals, Inc.

  15. Design and construction of a novel 1H/19F double-tuned coil system using PIN-diode switches at 9.4T.

    Science.gov (United States)

    Choi, Chang-Hoon; Hong, Suk-Min; Ha, YongHyun; Shah, N Jon

    2017-06-01

    A double-tuned 1 H/ 19 F coil using PIN-diode switches was developed and its performance evaluated. The is a key difference from the previous developments being that this design used a PIN-diode switch in series with an additionally inserted inductor in parallel to one of the capacitors on the loop. The probe was adjusted to 19 F when the reverse bias voltage was applied (PIN-diode OFF), whilst it was switched to 1 H when forward current was flowing (PIN-diode ON). S-parameters and Q-factors of single- and double-tuned coils were examined and compared with/without a phantom on the bench. Imaging experiments were carried out on a 9.4T preclinical scanner. All coils were tuned at resonance frequencies and matched well. It is shown that the Q-ratio and SNR of double-tuned coil at 19 F frequency are nearly as good as those of a single-tuned coil. Since the operating frequency was tuned to 19 F when the PIN-diodes were turned off, losses due to PIN-diodes were substantially lower resulting in the provision of excellent image quality of X-nuclei. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Sequestration of a fluorinated analog of 2,4-dichlorophenol and metabolic products by L. minor as evidenced by 19F NMR

    International Nuclear Information System (INIS)

    Tront, Jacqueline M.; Saunders, F. Michael

    2007-01-01

    Fate of halogenated phenols in plants was investigated using nuclear magnetic resonance (NMR) to identify and quantify contaminants and their metabolites. Metabolites of 4-chloro-2-fluorophenol (4-Cl-2-FP), as well as the parent compound, were detected in acetonitrile extracts using 19 F NMR after various exposure periods. Several fluorinated metabolites with chemical shifts ∼3.5 ppm from the parent compound were present in plant extracts. Metabolites isolated in extracts were tentatively identified as fluorinated-chlorophenol conjugates through examination of signal-splitting patterns and relative chemical shifts. Signal intensity was used to quantify contaminant and metabolite accumulation within plant tissues. The quantity of 4-Cl-2-F metabolites increased with time and mass balance closures of 90-110% were achieved. In addition, solid phase 19 F NMR was used to identify 4-Cl-2-FP which was chemically bound to plant material. This work used 19 F NMR for developing a time series description of contaminant accumulation and transformation in aquatic plant systems. - The aquatic plant L. minor accumulates, sequesters and binds 4-chloro-2-fluorophenol and its metabolites, as was demonstrated using 19 F-NMR

  17. Direct mapping of 19F in 19FDG-6P in brain tissue at subcellular resolution using soft X-ray fluorescence

    Science.gov (United States)

    Poitry-Yamate, C.; Gianoncelli, A.; Kourousias, G.; Kaulich, B.; Lepore, M.; Gruetter, R.; Kiskinova, M.

    2013-10-01

    Low energy x-ray fluorescence (LEXRF) detection was optimized for imaging cerebral glucose metabolism by mapping the fluorine LEXRF signal of 19F in 19FDG, trapped as intracellular 19F-deoxyglucose-6-phosphate (19FDG-6P) at 1μm spatial resolution from 3μm thick brain slices. 19FDG metabolism was evaluated in brain structures closely resembling the general cerebral cytoarchitecture following formalin fixation of brain slices and their inclusion in an epon matrix. 2-dimensional distribution maps of 19FDG-6P were placed in a cytoarchitectural and morphological context by simultaneous LEXRF mapping of N and O, and scanning transmission x-ray (STXM) imaging. A disproportionately high uptake and metabolism of glucose was found in neuropil relative to intracellular domains of the cell body of hypothalamic neurons, showing directly that neurons, like glial cells, also metabolize glucose. As 19F-deoxyglucose-6P is structurally identical to 18F-deoxyglucose-6P, LEXRF of subcellular 19F provides a link to in vivo 18FDG PET, forming a novel basis for understanding the physiological mechanisms underlying the 18FDG PET image, and the contribution of neurons and glia to the PET signal.

  18. Direct mapping of 19F in 19FDG-6P in brain tissue at subcellular resolution using soft X-ray fluorescence

    International Nuclear Information System (INIS)

    Poitry-Yamate, C; Lepore, M; Gruetter, R; Gianoncelli, A; Kourousias, G; Kiskinova, M; Kaulich, B

    2013-01-01

    Low energy x-ray fluorescence (LEXRF) detection was optimized for imaging cerebral glucose metabolism by mapping the fluorine LEXRF signal of 19 F in 19 FDG, trapped as intracellular 19 F-deoxyglucose-6-phosphate ( 19 FDG-6P) at 1μm spatial resolution from 3μm thick brain slices. 19 FDG metabolism was evaluated in brain structures closely resembling the general cerebral cytoarchitecture following formalin fixation of brain slices and their inclusion in an epon matrix. 2-dimensional distribution maps of 19 FDG-6P were placed in a cytoarchitectural and morphological context by simultaneous LEXRF mapping of N and O, and scanning transmission x-ray (STXM) imaging. A disproportionately high uptake and metabolism of glucose was found in neuropil relative to intracellular domains of the cell body of hypothalamic neurons, showing directly that neurons, like glial cells, also metabolize glucose. As 19 F-deoxyglucose-6P is structurally identical to 18 F-deoxyglucose-6P, LEXRF of subcellular 19 F provides a link to in vivo 18 FDG PET, forming a novel basis for understanding the physiological mechanisms underlying the 18 FDG PET image, and the contribution of neurons and glia to the PET signal

  19. Study of function response of a detector HPGe to photons of reaction 19F(p,αγ)16O

    International Nuclear Information System (INIS)

    Tridapalli, D.B.

    2006-01-01

    In the 19 F(p,αγ) 16 O reaction, characteristic gamma-rays with energies: 6.1 MeV; 6.9 MeV and 7.1 keV can be observed. These photons can be used in many important applications such as Proton Induced Gamma-ray Emission (PIGE), gamma radiography and calibration purposes. It has another advantage in calibration procedures, which is the observed photon flux is greater than other reactions studied, 27 Al(p,αγ) 28 Si and 23 Na(p,αγ) 24 Mg. In our laboratory, we are studying the efficiency and response function of HPGe detectors for high energy photons, and for this it is necessary a source with a level scheme with few gamma-ray transitions and known relative yields. The 19 F(p,αγ) 16 O reaction satisfies the first condition but in the literature we found relative yields for thick targets or reaction cross section for thin targets. However, we use targets of intermediate thickness, therefore in this work we measure the relative gamma-ray yields for protons with energies between 1.36 MeV and 1.42 MeV. The experiments were performed at the 1.7 MV Pelletron tandem accelerator of the Laboratorio de Analise de Materiais por Feixes Ionicos (LAMFI) located at Instituto de Fisica da Universidade de Sao Paulo, using a reverse-electrode closed-end coaxial HPGe detector with 72.5 mm in diameter and 60.5 mm in length, at 0 deg. The proton irradiation current was 50 nA, and the target consisted of 250 μg/cm 2 CaF 2 evaporated on a 0.1 mm Ta backing. In this reaction the 20 Ne resonant state fissions in flight, and the resulting 16 O excited states have different half-lives; all observed peaks are deformed due to either Doppler broadening from 16 O random velocity direction or Doppler shift from nuclei that leave the target toward the vacuum chamber. Moreover, the peak deformations vary with the proton energy. These deformations were modeled by a Monte Carlo simulation that follows the oxygen nuclei in its trajectory until photon emission, considering the changes in spatial

  20. Studies of the pH dependence of 13C shifts and carbon-carbon coupling constants of [U-13C]aspartic and -glutamic acids

    International Nuclear Information System (INIS)

    London, R.E.; Walker, T.E.; Kollman, V.H.; Matwiyoff, N.A.

    1978-01-01

    13 C NMR studies of the chemical shifts and carbon--carbon spin--spin coupling constants of 90% [U- 13 C]aspartic and -glutamic acids are reported. Effects of titration of the two carboxyl groups are separated computationally and the results compared with those for asparagine and glutamine, aspartate and glutamate containing peptides, and a series of amino-n-butyric acids. The results indicate that the carboxyl carbon shift resulting from titration of the carboxyl group is strongly dependent on its distance (number of bonds) from an amino group. Alternatively, remote methyl groups exhibit a much smaller titration induced shift than carboxyl groups in the corresponding position. Significant remote effects of pH titration on the one-bond carbon-carbon coupling are also observed, particularly for couplings involving the side-chain carboxyl carbons. These results are discussed in terms of polarization of the C--O bonds in response to titration of a remote carboxyl group. Values of 3 J/sub CC/ in asparate and glutamate indicate a strong conformational dependence. Rotamer populations predicted on the basis of the observed couplings and theoretical INDO calculations are in good agreement with values based on analysis of the 3 J/sub HH/ and 3 J/sub CH/ couplings. For a given conformation of glutamic acid, it is found that 3 J 14 is considerably smaller than 3 J 25 . This result is consistent with obsrvations on a number of other 13 C-labeled amino acids. 5 figures, 4 tables

  1. 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

  2. 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

  3. 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

  4. 13C trend in an Egyptian recent tree as a record for global carbon dioxide behaviour

    International Nuclear Information System (INIS)

    Aly, A.I.M.; Belacy, N.; Abou El-Nour, F.

    1988-01-01

    The record of the 13 C content in tree rings of an Egyptian tree is used as indication for the increase of the atmospheric carbon dioxide concentration. A decrease of the 13 C isotopic content of the tree rings is observed starting from 1940 coinciding with a significant increase in the global production of CO 2 due to combustion of fossil fuel depleted in 13 C with respect to the atmosphere. Considering the local as well as the global CO 2 production rates together with the measured isotopic data, it may be concluded that the behaviour of carbon dioxide in the investigated Eastern Delta province in Egypt reflects mainly a global rather than a local effect. (author)

  5. 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)

  6. 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)

  7. 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

  8. 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.

  9. 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.

  10. 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)

  11. Identification of natural metabolites in mixture: a pattern recognition strategy based on (13)C NMR.

    Science.gov (United States)

    Hubert, Jane; Nuzillard, Jean-Marc; Purson, Sylvain; Hamzaoui, Mahmoud; Borie, Nicolas; Reynaud, Romain; Renault, Jean-Hugues

    2014-03-18

    Because of their highly complex metabolite profile, the chemical characterization of bioactive natural extracts usually requires time-consuming multistep purification procedures to achieve the structural elucidation of pure individual metabolites. The aim of the present work was to develop a dereplication strategy for the identification of natural metabolites directly within mixtures. Exploiting the polarity range of metabolites, the principle was to rapidly fractionate a multigram quantity of a crude extract by centrifugal partition extraction (CPE). The obtained fractions of simplified chemical composition were subsequently analyzed by (13)C NMR. After automatic collection and alignment of (13)C signals across spectra, hierarchical clustering analysis (HCA) was performed for pattern recognition. As a result, strong correlations between (13)C signals of a single structure within the mixtures of the fraction series were visualized as chemical shift clusters. Each cluster was finally assigned to a molecular structure with the help of a locally built (13)C NMR chemical shift database. The proof of principle of this strategy was achieved on a simple model mixture of commercially available plant secondary metabolites and then applied to a bark extract of the African tree Anogeissus leiocarpus Guill. & Perr. (Combretaceae). Starting from 5 g of this genuine extract, the fraction series was generated by CPE in only 95 min. (13)C NMR analyses of all fractions followed by pattern recognition of (13)C chemical shifts resulted in the unambiguous identification of seven major compounds, namely, sericoside, trachelosperogenin E, ellagic acid, an epimer mixture of (+)-gallocatechin and (-)-epigallocatechin, 3,3'-di-O-methylellagic acid 4'-O-xylopyranoside, and 3,4,3'-tri-O-methylflavellagic acid 4'-O-glucopyranoside.

  12. Oceanic uptake of CO2 re-estimated through δ13C in WOCE samples

    International Nuclear Information System (INIS)

    Lerperger, Michael; McNichol, A.P.; Peden, J.; Gagnon, A.R.; Elder, K.L.; Kutschera, W.; Rom, W.; Steier, P.

    2000-01-01

    In addition to 14 C, a large set of δ 13 C data was produced at NOSAMS as part of the World ocean circulation experiment (WOCE). In this paper, a subset of 973 δ 13 C results from 63 stations in the Pacific Ocean was compared to a total number of 219 corresponding results from 12 stations sampled during oceanographic programs in the early 1970s. The data were analyzed in light of recent work to estimate the uptake of CO 2 derived from fossil fuel and biomass burning in the oceans by quantifying the δ 13 C Suess effect in the oceans. In principle, the δ 13 C value of dissolved inorganic carbon (DIC) allows a quantitative estimate of how much of the anthropogenic CO 2 released into the atmosphere is taken up by the oceans, because the δ 13 C of CO 2 derived from organic matter (∼2.7 percent) is significantly different from that of the atmosphere (∼0.8 percent). Our new analysis indicates an apparent discrepancy between the old and the new data sets, possibly caused by a constant offset in δ 13 C values in a subset of the data. A similar offset was reported in an earlier work by Paul Quay et al. for one station that was not included in their final analysis. We present an estimate for this assumed offset based on data from water depths below which little or no change in δ 13 C over time would be expected. Such a correction leads to a significantly reduced estimate of the CO 2 uptake, possibly as low as one half of the amount of 2.1 GtC yr -1 (gigatons carbon per year) estimated previously. The present conclusion is based on a comparison with a relatively small data set from the 70s in the Pacific Ocean. The larger data set collected during the GEOSECS program was not used because of problems reported with the data. This work suggests there may also be problems in comparing non-GEOSECS data from the 1970s to the current data. The calculation of significantly lower uptake estimates based on an offset-related problem appears valid, but the exact figures are

  13. Direct 13C-1H coupling constants in the vinyl group of 1-vinylpyrazoles

    International Nuclear Information System (INIS)

    Afonin, A.V.; Voronov, V.K.; Es'kova, L.A.; Domnina, E.S.; Petrova, E.V.; Zasyad'ko, O.V.

    1987-01-01

    In a continuation of a study of the rotational isomerism of 1-vinylpyrazoles, they studied the direct 13 C- 1 H coupling constants in the vinyl group of 1-vinylpyrazole, 1-vinyl-4-bromopyrazole, 1-vinyl-3-methylpyrazole, 1-vinyl-5-methylpyrazole, 1-vinyl-3,5-dimethylpyrazole, and 1-vinyl-4-nitro-3,5-dimethylpyrazole. The 13 C- 1 H direct coupling constants in the vinyl group of 1-vinylpyrazoles are stereo-specific and vary with change in the conformer ratio

  14. Minimally invasive (13)C-breath test to examine phenylalanine metabolism in children with phenylketonuria.

    Science.gov (United States)

    Turki, Abrar; Murthy, Gayathri; Ueda, Keiko; Cheng, Barbara; Giezen, Alette; Stockler-Ipsiroglu, Sylvia; Elango, Rajavel

    2015-01-01

    Phenylketonuria (PKU) is an autosomal recessive disorder caused by deficiency of hepatic phenylalanine hydroxylase (PAH) leading to increased levels of phenylalanine in the plasma. Phenylalanine levels and phenylalanine hydroxylase (PAH) activity monitoring are currently limited to conventional blood dot testing. 1-(13)C-phenylalanine, a stable isotope can be used to examine phenylalanine metabolism, as the conversion of phenylalanine to tyrosine occurs in vivo via PAH and subsequently releases the carboxyl labeled (13)C as (13)CO2 in breath. Our objective was to examine phenylalanine metabolism in children with PKU using a minimally-invasive 1-(13)C-phenylalanine breath test ((13)C-PBT). Nine children (7 M: 2 F, mean age 12.5 ± 2.87 y) with PKU participated in the study twice: once before and once after sapropterin supplementation. Children were provided 6 mg/kg oral dose of 1-(13)C-phenylalanine and breath samples were collected at 20 min intervals for a period of 2h. Rate of CO2 production was measured at 60 min post-oral dose using indirect calorimetry. The percentage of 1-(13)C-phenylalanine exhaled as (13)CO2 was measured over a 2h period. Prior to studying children with PKU, we tested the study protocol in healthy children (n = 6; 4M: 2F, mean age 10.2 ± 2.48 y) as proof of principle. Production of a peak enrichment (Cmax) of (13)CO2 (% of dose) in all healthy children occurred at 20 min ranging from 17-29% of dose, with a subsequent return to ~5% by the end of 2h. Production of (13)CO2 from 1-(13)C-phenylalanine in all children with PKU prior to sapropterin treatment remained low. Following sapropterin supplementation for a week, production of (13)CO2 significantly increased in five children with a subsequent decline in blood phenylalanine levels, suggesting improved PAH activity. Sapropterin treatment was not effective in three children whose (13)CO2 production remained unchanged, and did not show a reduction in blood phenylalanine levels and improvement

  15. Cyclohexanecarbonitriles: Assigning Configurations at Quaternary Centers From 13C NMR CN Chemical Shifts.1

    Science.gov (United States)

    Wei, Guoqing

    2009-01-01

    13C NMR chemical shifts of the nitrile carbon in cyclohexanecarbonitriles directly correlate with the configuration of the quaternary, nitrile-bearing stereocenter. Comparing 13C NMR chemical shifts for over 200 cyclohexanecarbonitriles reveals that equatorially oriented nitriles resonate 3.3 ppm downfield, on average, from their axial counterparts. Pairs of axial/equatorial diastereomers varying only at the nitrile-bearing carbon consistently exhibit downfield shifts of δ 0.4–7.2 for the equatorial nitrile carbon, even in angularly substituted decalins and hydrindanes. PMID:19348434

  16. DARC PLURIDATA system: the /sup 13/C-N. M. R. data bank

    Energy Technology Data Exchange (ETDEWEB)

    Dubois, J E; Bonnet, J C [Paris-7 Univ., 75 (France)

    1979-09-15

    The capabilities of the DARC system are discussed and illustrated by the storage and retrieval functions of the /sup 13/C-N.M.R. data bank of the DARC PLURIDATA system. The data covered by the bank, as well as the input stream to the bank and validation of the spectra, are described. Particular stress is laid on the DARC structural retrieval system, which illustrates the interactive interrogration of a chemical bank by means of the structural diagram of a molecule, i.e. the universal language in chemistry. The potential of the /sup 13/C-N.M.R. data bank in computer-aided structural elucidation is outlined.

  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. 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.)

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

    DEFF Research Database (Denmark)

    Giovannetti, Giulio; Frijia, Francesca; Attanasio, Simona

    2013-01-01

    Hyperpolarized 13C magnetic resonance spectroscopy in pig models enables cardiac metabolism assessment and provides a powerful tool for heart physiology studies, although the low molar concentration of derivate metabolites gives rise to technological limitations in terms of data quality. The desi...... throughout the volume of interest for cardiac imaging in pig. Experimental SNR-vs-depth profiles, extracted from the [1-13C]acetate phantom chemical shift image (CSI), permitted to highlight the performance of the proposed coils configuration. © 2013 Elsevier Ltd. All rights reserved....

  20. The Late Devonian Frasnian-Famennian (F/F) biotic crisis: Insights from δ13C carb, δ13C org and 87Sr / 86Sr isotopic systematics

    Science.gov (United States)

    Chen, Daizhao; Qing, Hairuo; Li, Renwei

    2005-06-01

    A severe biotic crisis occurred during the Late Devonian Frasnian-Famennian (F/F) transition (± 367 Myr). Here we present δ13C carb, δ13C org and 87Sr / 86Sr isotopic systematics, from identical samples of two sections across F/F boundary in South China, which directly demonstrate large and frequent climatic fluctuations (˜200 kyr) from warming to cooling during the F/F transition. These climate fluctuations are interpreted to have been induced initially by increased volcanic outgassing, and subsequent enhanced chemical weathering linked to the rapid expansion of vascular plants on land, which would have increased riverine delivery to oceans and primary bioproductivity, and subsequent burial of organic matter, thereby resulting in climate cooling. Such large and frequent climatic fluctuations, together with volcanic-induced increases in nutrient (e.g., biolimiting Fe), toxin (sulfide) and anoxic water supply, and subsequent enhanced riverine fluxes and microbial bloom, were likely responsible for the stepwise faunal demise of F/F biotic crisis.

  1. 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.

  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. 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...

  4. 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

  5. Microstructure study of ethylene, propylene and 1-decene terpolymers by 13C-NMR

    International Nuclear Information System (INIS)

    Ferreira, Marcio; Escher, Fernanda Nunes; Galland, Griselda Barrera

    2001-01-01

    Terpolymers of ethylene-propylene-1-decene with different composition of monomers were obtained using the metallocenes catalyst rac-EtInd 2 ZrCl 2 . The complete 13 C-NMR characterization of these terpolymers was done qualitatively and quantitatively. Chemical shifts, carbon assignments and corresponding integrals for each triad sequence are presented. (author)

  6. Diagnostic Limitations of 13C-Mixed Triglyceride Breath Test in Patients after Cholecystectomy

    Directory of Open Access Journals (Sweden)

    V.I. Rusyn

    2014-09-01

    Full Text Available The results of a comprehensive examination of 136 patients after cholecystectomy are provided. High efficiency and informativeness of the 13C-mixed triglyceride breath test for determining exocrine pancreatic insufficiency at its early stages was noted in patients after cholecystectomy.

  7. 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

  8. Probing the possibility of a 12C13C abundance gradient from observations of interstellar CH+

    International Nuclear Information System (INIS)

    Hawkins, I.

    1987-01-01

    I have performed high signal-to-noise (SN /equals/ 300 to 500) observations of interstellar CH/sup /plus// at Lick Observatory and at CTIO of the reddened, early-type stars HD 183143, HD 24432, and HD 157038 in an effort to probe the existence of a 12 C 13 C abundance gradient in our Galaxy

  9. 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

  10. 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

  11. Configurations and conformations in acyclic, unsaturated hydrocarbons. A 13C NMR study

    NARCIS (Netherlands)

    Haan, de J.W.; Ven, van de L.J.M.

    1973-01-01

    13C NMR (CMR) spectra of a number of di- and trisubstituted ethylenes have been measured. Very consistent values are found for the differential shieldings of allylic carbons in a number of linear, (Z)- and (E)-disubstituted ethylenes. The discrepancies between the several structural elements are

  12. 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

  13. Determination of the δ13C of dissolved inorganic carbon in water; RSIL lab code 1710

    Science.gov (United States)

    Singleton, Glenda L.; Revesz, Kinga; Coplen, Tyler B.

    2012-01-01

    The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 1710 is to present a method to determine the δ13C of dissolved inorganic carbon (DIC) of water. The DIC of water is precipitated using ammoniacal strontium chloride (SrCl2) solution to form strontium carbonate (SrCO3). The δ13C is analyzed by reacting SrCO3 with 100-percent phosphoric acid (H3PO4) to liberate carbon quantitatively as carbon dioxide (CO2), which is collected, purified by vacuum sublimation, and analyzed by dual inlet isotope-ratio mass spectrometry (DI-IRMS). The DI-IRMS is a DuPont double-focusing mass spectrometer. One ion beam passes through a slit in a forward collector and is collected in the rear collector. The other measurable ion beams are collected in the front collector. By changing the ion-accelerating voltage under computer control, the instrument is capable of measuring mass/charge (m/z) 45 or 46 in the rear collector and m/z 44 and 46 or 44 and 45, respectively, in the front collector. The ion beams from these m/z values are as follows: m/z 44 = CO2 = 12C16O16O, m/z 45 = CO2 = 13C16O16O primarily, and m/z 46 = CO2 = 12C16O18O primarily. The data acquisition and control software calculates δ13C values.

  14. 13C NMR spectra and bonding situation of the B-C bond in alkynylboranes

    International Nuclear Information System (INIS)

    Yamamoto, Yoshinori; Moritani, Ichiro

    1975-01-01

    13 C NMR spectra of boron substituted alkynes reveal that the β-carbon is deshielded by ca. 21 ppm by a B(O-n-C 4 H 9 ) 2 group. This clearly indicates the presence of a B-C π-bonding in alkynylboranes. (auth.)

  15. 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.

  16. Iminium ion chemistry of mitosene DNA alkylating agents. Enriched 13C NMR and isolation studies.

    Science.gov (United States)

    Ouyang, A; Skibo, E B

    2000-05-16

    Described herein is a study of the reductive alkylation chemistry of mitosene antitumor agents. We employed a 13C-enriched electrophilic center to probe the fate of the iminium ion resulting from reductive activation. The 13C-labeled center permitted the identification of complex products resulting from alkylation reactions. In the case of DNA reductive alkylation, the type and number of alkylation sites were readily assessed by 13C NMR. Although there has been much excellent work done in the area of mitosene chemistry and biochemistry, the present study provides a number of new findings: (1) The major fate of the iminium ion is head-to-tail polymerization, even in dilute solutions. (2) Dithionite reductive activation results in the formation of mitosene sulfite esters as well as the previously observed sulfonate adducts. (3) The mitosene iminium ion alkylates the adenosine 6-amino group as well as the guanosine 2-amino group. The identification of the latter adduct was greatly facilitated by the 13C-label at the electrophilic center. (4) The mitosene iminium ion alkylates DNA at both nitrogen and oxygen centers without any apparent base selectivity. The complexity of mitosene reductive alkylation of DNA will require continued adduct isolation studies.

  17. (1 H, 13 C and 31 P) NMR of phosphonic acid derivatives

    International Nuclear Information System (INIS)

    Campos, Valdevino; Costa, Valentim E. Uberti

    1991-01-01

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

  18. 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.

  19. Aspects of reaction of N-oxide radical with ethers in 13C NMR spectrum

    International Nuclear Information System (INIS)

    Kolodziejski, W.

    1980-01-01

    The stable radical N-oxide 2,2,6,6-tetramethylpiperidine was dissolved in ethers. The 13 C NMR spectra were recorded in the temperature 313K at the frequency 22,625 MHz on the spectrometers with Fourier transformation. The dissolution of the radical in ether caused the contact shifts in NMR spectra. The shifts were measured. (A.S.)

  20. In vivo single-shot (13)C spectroscopic imaging of hyperpolarized metabolites by spatiotemporal encoding

    DEFF Research Database (Denmark)

    Schmidt, Rita; Laustsen, Christoffer; Dumez, Jean-Nicolas

    2014-01-01

    are necessary. Several approaches have been customized for hyperpolarized (13)C MRI, including CSI with a center-out k-space encoding, EPSI, and spectrally selective pulses in combination with spiral EPI acquisitions. Recent studies have described the potential of single-shot alternatives based...... temporal) data sets were obtained at 7T from a murine lymphoma tumor model....

  1. 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

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    , by permitting metabolic activity mapping, a number of technological problems still limit this technology and need innovative solutions such as the design of suitable radiofrequency (RF) coils, capable to provide a large sensitivity region. This work describes the simulation and the comparison of different 13C...

  3. Apparent rate constant mapping using hyperpolarized [1-(13) C]pyruvate

    DEFF Research Database (Denmark)

    Khegai, O.; Schulte, R. F.; Janich, M. A.

    2014-01-01

    Hyperpolarization of [1-13C]pyruvate in solution allows real-time measurement of uptake and metabolism using MR spectroscopic methods. After injection and perfusion, pyruvate is taken up by the cells and enzymatically metabolized into downstream metabolites such as lactate, alanine, and bicarbona...

  4. Soil carbon inventories and d 13C along a moisture gradient in Botswana

    NARCIS (Netherlands)

    Bird, M.I.; Veenendaal, E.M.; Lloyd, J.

    2004-01-01

    We present a study of soil organic carbon (SOC) inventories and d 13C values for 625 soil cores collected from well-drained, coarse-textured soils in eight areas along a 1000 km moisture gradient from Southern Botswana, north into southern Zambia. The spatial distribution of trees and grass in the

  5. Sequential nearest-neighbor effects on computed {sup 13}C{sup {alpha}} chemical shifts

    Energy Technology Data Exchange (ETDEWEB)

    Vila, Jorge A. [Cornell University, Baker Laboratory of Chemistry and Chemical Biology (United States); Serrano, Pedro; Wuethrich, Kurt [The Scripps Research Institute, Department of Molecular Biology (United States); Scheraga, Harold A., E-mail: has5@cornell.ed [Cornell University, Baker Laboratory of Chemistry and Chemical Biology (United States)

    2010-09-15

    To evaluate sequential nearest-neighbor effects on quantum-chemical calculations of {sup 13}C{sup {alpha}} chemical shifts, we selected the structure of the nucleic acid binding (NAB) protein from the SARS coronavirus determined by NMR in solution (PDB id 2K87). NAB is a 116-residue {alpha}/{beta} protein, which contains 9 prolines and has 50% of its residues located in loops and turns. Overall, the results presented here show that sizeable nearest-neighbor effects are seen only for residues preceding proline, where Pro introduces an overestimation, on average, of 1.73 ppm in the computed {sup 13}C{sup {alpha}} chemical shifts. A new ensemble of 20 conformers representing the NMR structure of the NAB, which was calculated with an input containing backbone torsion angle constraints derived from the theoretical {sup 13}C{sup {alpha}} chemical shifts as supplementary data to the NOE distance constraints, exhibits very similar topology and comparable agreement with the NOE constraints as the published NMR structure. However, the two structures differ in the patterns of differences between observed and computed {sup 13}C{sup {alpha}} chemical shifts, {Delta}{sub ca,i}, for the individual residues along the sequence. This indicates that the {Delta}{sub ca,i} -values for the NAB protein are primarily a consequence of the limited sampling by the bundles of 20 conformers used, as in common practice, to represent the two NMR structures, rather than of local flaws in the structures.

  6. Detection of Helicobacter pylori in rural school children using 13C ...

    African Journals Online (AJOL)

    ulcer, gastric ulcer, non-ulcer dyspepsia and gastritis. Several diagnostic methods are available for the detection of H. pylori, with direct methods based on gastric biopsies. The 13C- Urea Breath Test (UBT) used in this study has advantage over the other methods in that, it is easy to perform, specific (100%), highly sensitive ...

  7. (13)C-(15)N correlation via unsymmetrical indirect covariance NMR: application to vinblastine.

    Science.gov (United States)

    Martin, Gary E; Hilton, Bruce D; Blinov, Kirill A; Williams, Antony J

    2007-12-01

    Unsymmetrical indirect covariance processing methods allow the derivation of hyphenated 2D NMR data from the component 2D spectra, potentially circumventing the acquisition of the much lower sensitivity hyphenated 2D NMR experimental data. Calculation of HSQC-COSY and HSQC-NOESY spectra from GHSQC, COSY, and NOESY spectra, respectively, has been reported. The use of unsymmetrical indirect covariance processing has also been applied to the combination of (1)H- (13)C GHSQC and (1)H- (15)N long-range correlation data (GHMBC, IMPEACH, or CIGAR-HMBC). The application of unsymmetrical indirect covariance processing to spectra of vinblastine is now reported, specifically the algorithmic extraction of (13)C- (15)N correlations via the unsymmetrical indirect covariance processing of the combination of (1)H- (13)C GHSQC and long-range (1)H- (15)N GHMBC to produce the equivalent of a (13)C- (15)N HSQC-HMBC correlation spectrum. The elimination of artifact responses with aromatic solvent-induced shifts (ASIS) is shown in addition to a method of forecasting potential artifact responses through the indirect covariance processing of the GHSQC spectrum used in the unsymmetrical indirect covariance processing.

  8. 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)

  9. Hyperpolarized 1-13C Pyruvate Imaging of Porcine Cardiac Metabolism shift by GIK Intervention

    DEFF Research Database (Denmark)

    Søvsø Szocska Hansen, Esben; Tougaard, Rasmus Stilling; Mikkelsen, Emmeli

    to evaluate the general feasibility to detect an imposed shift in metabolic substrate utilization during metabolic modulation with glucose, insulin and potassium (GIK) infusion. This study demonstrates that hyperpolarized 13C-pyruvate, in a large animal, is a feasible method for cardiac studies, and...

  10. Sources of variation in δ13C of fossil fuel emissions in Salt Lake City, USA

    International Nuclear Information System (INIS)

    Bush, S.E.; Pataki, D.E.; Ehleringer, J.R.

    2007-01-01

    The isotopic composition of fossil fuels is an important component of many studies of C sources and sinks based on atmospheric measurements of CO 2 . In C budget studies, the isotopic composition of crude petroleum and CH 4 are often used as a proxy for the isotopic composition of CO 2 emissions from combustion. In this study, the C isotope composition (δ 13 C) of exhaust from the major fossil fuel emission sources in Salt Lake City, USA, was characterized with 159 measurements of vehicle exhaust of various types and eight measurements of residential furnace exhaust. These two sources were found to be isotopically distinct, and differed from global-scale estimates based on average values for crude petroleum and CH 4 . Vehicle-specific factors such as engine load and operation time had no effect on δ 13 C of vehicle exhaust. A small difference was found between the mean δ 13 C of vehicle exhaust collected randomly from different vehicles and the mean δ 13 C of gasoline collected from multiple fueling stations representing major gasoline distributors in Salt Lake City and the surrounding area. However, a paired comparison of δ 13 C of exhaust and gasoline for six different vehicles did not show any consistent C isotope fractionation during vehicle combustion. The mean δ 13 C of crude petroleum processed for local distribution differed slightly from refined gasoline collected at multiple fueling stations, but time lags between processing and transportation cannot be ruled out as an uncontrollable contributing factor. Measured isotope ratios were then combined with fuel consumption statistics to predict the annual cycle of δ 13 C of fossil fuel emissions for the Salt Lake City metropolitan area. The results showed that the isotopic composition of CO 2 emissions from fossil fuel combustion varied by almost 3 per mille over the course of the 2002 calendar year. This study illustrates that on a regional scale, the isotopic composition of fossil fuel emissions shows

  11. Stable carbon isotope analysis (δ13C values) of polybrominated diphenyl ethers and their UV-transformation products

    International Nuclear Information System (INIS)

    Rosenfelder, Natalie; Bendig, Paul; Vetter, Walter

    2011-01-01

    Polybrominated diphenyl ethers (PBDEs) are frequently detected in food and environmental samples. We used compound specific isotope analysis to determine the δ 13 C values of individual PBDEs in two technical mixtures. Within the same technical product (DE-71 or DE-79), BDE congeners were the more depleted in 13 C the higher brominated they were. In contrast, the products of light-induced hydrodebromination of BDE 47 and technical DE-79 were more enriched in 13 C because of more stable bonds between 13 C and bromine. As a result, the δ 13 C values of the irradiated solution progressed diametrically compared to those of the technical synthesis. The ratio of the δ 13 C values of BDE 47 to BDE 99 and of BDE 99 to BDE 153 are thus suggested as indicators to distinguish native technical products from transformation products. Ratios 1) is typical of transformation products. - Highlights: → δ 13 C values of PBDEs were determined by means of compound specific isotope analysis. → PBDEs in technical mixtures were the more depleted in 13 C the higher they were brominated. → Solutions of individual PBDEs and technical PBDE mixtures were irradiated by UV light. → δ 13 C values of irradiated PBDEs and technical PBDEs progressed diametrically. → Ratios of the δ 13 C values were used to distinguish native from transformed PBDEs. - Diametrically progressing δ 13 C values in technical mixtures and UV-transformation products of DE-79 may be useful for source appointment of PBDEs in environmental samples

  12. Turnover of carbon in the 13C-urea breath test for the detection of Helicobacter pylori infection

    International Nuclear Information System (INIS)

    Costa, Vladimir E.; Andreazzi, Mariana; Cury, Caio S.; Bassetto Junior, Carlos A.Z.; Rodrigues, Maria A.M.; Ducatti, Carlos

    2013-01-01

    To obtain a standard protocol for the application of 13 C-urea breath test ( 13 C-UBT) analyzed by Isotope Ratio Mass Spectrometer (IRMS) to detect helicobacter pylori infection in the population is necessary to know the behavior of the turnover of 13 C during the test in different individuals. The aims of this study was to find out a pattern for the turnover of the 13 C in the 13 C-UBT, analyzed by IRMS, in patients infected with H. pylori, in a Brazilian population, to define a protocol test application. We found that the isotopic ratio 13 C/ 12 C in expired CO 2 from patients infected with H. pylori and subjected to 13 C-UBT does not follow a single pattern of behavior. However this behavior can be similar in subjects having the same maximum values following an inverse proportional relationship between the maximum value and the time of appearance in the curve. (author)

  13. 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

  14. 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.

  15. Quantitative analysis of deuterium using the isotopic effect on quaternary {sup 13}C NMR chemical shifts

    Energy Technology Data Exchange (ETDEWEB)

    Darwish, Tamim A., E-mail: tamim.darwish@ansto.gov.au [National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Locked Bag 21, Kirrawee DC, NSW 2232 (Australia); Yepuri, Nageshwar Rao; Holden, Peter J. [National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Locked Bag 21, Kirrawee DC, NSW 2232 (Australia); James, Michael [Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia)

    2016-07-13

    Quantitative analysis of specifically deuterated compounds can be achieved by a number of conventional methods, such as mass spectroscopy, or by quantifying the residual {sup 1}H NMR signals compared to signals from internal standards. However, site specific quantification using these methods becomes challenging when dealing with non-specifically or randomly deuterated compounds that are produced by metal catalyzed hydrothermal reactions in D{sub 2}O, one of the most convenient deuteration methods. In this study, deuterium-induced NMR isotope shifts of quaternary {sup 13}C resonances neighboring deuterated sites have been utilized to quantify the degree of isotope labeling of molecular sites in non-specifically deuterated molecules. By probing {sup 13}C NMR signals while decoupling both proton and deuterium nuclei, it is possible to resolve {sup 13}C resonances of the different isotopologues based on the isotopic shifts and the degree of deuteration of the carbon atoms. We demonstrate that in different isotopologues, the same quaternary carbon, neighboring partially deuterated carbon atoms, are affected to an equal extent by relaxation. Decoupling both nuclei ({sup 1}H, {sup 2}H) resolves closely separated quaternary {sup 13}C signals of the different isotopologues, and allows their accurate integration and quantification under short relaxation delays (D1 = 1 s) and hence fast accumulative spectral acquisition. We have performed a number of approaches to quantify the deuterium content at different specific sites to demonstrate a convenient and generic analysis method for use in randomly deuterated molecules, or in cases of specifically deuterated molecules where back-exchange processes may take place during work up. - Graphical abstract: The relative intensities of quaternary {sup 13}C {"1H,"2H} resonances are equal despite the different relaxation delays, allowing the relative abundance of the different deuterated isotopologues to be calculated using NMR fast

  16. 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

  17. 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

  18. 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

  19. Mono terpenes characterization by {sup 1} H and {sup 13} C-1 NMR; Caracterizacao de monoterpenos por RMN - {sup 1} H e de {sup 13} C-1

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Martha T. de [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Fisico-Quimica; Silveira, Carmen L.P. [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Quimica Organica; Mcchesney, James D [Mississippi Univ., University, MS (United States). Research Inst. of Pharmaceutical Sciences

    1992-12-31

    Artemisinine, a new lactone sesquiterpene containing one peroxide binding, is the main anti malarial agent obtained from the Artemisia annua L. Viewing to obtain a simple synthetic route for artemisinic acid preparation, which is the key intermediary for total synthesis of this type of anti malarial agent, R-carvone has been chosen as starting material. The S-carvone was used as model for reaction optimization and preparation of derivatives to be used for NMR studies. The main objective of this work is the signalling of the {sup 13} C and {sup 1} H NMR spectra, using the 2 D-COSY and 2 D-Hector spectra 4 refs., 3 figs., 1 tab

  20. Forward modeling of fluctuating dietary 13C signals to validate 13C turnover models of milk and milk components from a diet-switch experiment.

    Directory of Open Access Journals (Sweden)

    Alexander Braun

    Full Text Available Isotopic variation of food stuffs propagates through trophic systems. But, this variation is dampened in each trophic step, due to buffering effects of metabolic and storage pools. Thus, understanding of isotopic variation in trophic systems requires knowledge of isotopic turnover. In animals, turnover is usually quantified in diet-switch experiments in controlled conditions. Such experiments usually involve changes in diet chemical composition, which may affect turnover. Furthermore, it is uncertain if diet-switch based turnover models are applicable under conditions with randomly fluctuating dietary input signals. Here, we investigate if turnover information derived from diet-switch experiments with dairy cows can predict the isotopic composition of metabolic products (milk, milk components and feces under natural fluctuations of dietary isotope and chemical composition. First, a diet-switch from a C3-grass/maize diet to a pure C3-grass diet was used to quantify carbon turnover in whole milk, lactose, casein, milk fat and feces. Data were analyzed with a compartmental mixed effects model, which allowed for multiple pools and intra-population variability, and included a delay between feed ingestion and first tracer appearance in outputs. The delay for milk components and whole milk was ~12 h, and that of feces ~20 h. The half-life (t½ for carbon in the feces was 9 h, while lactose, casein and milk fat had a t½ of 10, 18 and 19 h. The (13C kinetics of whole milk revealed two pools, a fast pool with a t½ of 10 h (likely representing lactose, and a slower pool with a t½ of 21 h (likely including casein and milk fat. The diet-switch based turnover information provided a precise prediction (RMSE ~0.2 ‰ of the natural (13C fluctuations in outputs during a 30 days-long period when cows ingested a pure C3 grass with naturally fluctuating isotope composition.

  1. Trifluorothymidine. Potential non-invasive diagnosis of herpes simplex infection using /sup 19/F nuclear magnetic resonance in a murine hepatitis model

    Energy Technology Data Exchange (ETDEWEB)

    Rand, K H; Raad, I; Houck, H J; El Koussi, A; Loftsson, T; Bodor, N; Brey, W; Rocca, J

    1987-12-01

    Trifluorothymidine (TFT) is known to be concentrated in herpes simplex virus (HSV) infected cells in vitro in the form of phosphorylated derivatives. The authors studied a murine hepatitis model of HSV infection to determine whether this in vitro observation would also be demonstrable in vivo. Following i.v. injection of 100 or 160 mg/kg TFT, TFT was found in significantly higher concentrations in the livers of HSV-2 infected mice than in the livers of uninfected mice, mice infected with murine hepatitis virus or mice with hepatitis from carbon tetrachloride treatment. Neither altered renal function, nor altered pharmacokinetics could account for this difference. /sup 19/F nuclear magnetic resonance spectroscopy readily detected the /sup 19/F from TFT in both liver extracts and whole livers, particularly at higher tissue levels, i.e. >50 ..mu..g/g tissue. If further studies with living animals support these preliminary observations, clinical application could be pursued. 34 refs.; 4 figs.; 3 tabs.

  2. The Effect of Intermolecular Halogen Bond on 19F DNP Enhancement in 1, 4-Diiodotetrafluorobenzene/4-OH-TEMPO Supramolecular Assembly

    Directory of Open Access Journals (Sweden)

    GAO Shan

    2017-12-01

    Full Text Available Halogen bond, as hydrogen bond, is a non-covalent bond. Dynamic nuclear polarization (DNP technique has been used previously to study hydrogen bonds-mediated intermolecular interactions. However, no study has been carried out so far to study the halogen bond-mediated intermolecular interactions with DNP. In this work, 19F DNP polarization efficiency of the halogen bonds existing in supramolecular assembling by 4-OH-TEMPO and 1,4-diiodotetrafluorobenzene (DITFB was studied on a home-made DNP system. The formation of intermolecular halogen bonds appeared to increase 19F DNP polarization efficiency, suggesting that the spin-spin interactions among electrons were weakened by the halogen bonds, resulting in an increased T2e and a larger saturation factor.

  3. The fluorine destruction in stars: First experimental study of the 19F(p,α)16O reaction at astrophysical energies

    International Nuclear Information System (INIS)

    La Cognata, M.; Mukhamedzhanov, A.; Spitaleri, C.; Indelicato, I.; Aliotta, M.; Burjan, V.; Cherubini, S.; Coc, A.; Gulino, M.; Hons, Z.; Kiss, G. G.; Kroha, V.; Lamia, L.; Mrazek, J.; Palmerini, S.; Piskor, S.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.

    2012-01-01

    The 19 F(p,α) 16 O reaction is an important fluorine destruction channel in the proton-rich outer layers of asymptotic giant branch (AGB) stars and it might also play a role in hydrogendeficient post-AGB star nucleosynthesis. So far, available direct measurements do not reach the energy region of astrophysical interest (E cm ∼ 300 keV), because of the hindrance effect of the Coulomb barrier. The Trojan Horse (TH) method was thus used to access this energy region, by extracting the quasi-free contribution to the 2 H( 19 F,α 16 O)n reaction. The TH measurement of the α 0 channel, which is the dominant one at such energies, shows the presence of resonant structures not observed before that cause an increase of the reaction rate at astrophysical temperatures up to a factor of 1.7, with potential important consequences for stellar nucleosynthesis.

  4. Angular momentum distribution for the formation of evaporation residues in fusion of 19F with 184W near the Coulomb barrier

    International Nuclear Information System (INIS)

    Nath, S.; Gehlot, J.; Prasad, E.; Sadhukhan, Jhilam; Shidling, P.D.; Madhavan, N.; Muralithar, S.; Golda, K.S.; Jhingan, A.; Varughese, T.; Rao, P.V. Madhusudhana; Sinha, A.K.; Pal, Santanu

    2011-01-01

    We present γ-ray multiplicity distributions for the formation of evaporation residues in the fusion reaction 19 F + 184 W → 203 83 Bi 120 at beam energies in the range of 90-110 MeV. The measurements were carried out using a 14 element BGO detector array and the Heavy Ion Reaction Analyzer at the Inter University Accelerator Centre. The data have been unfolded to obtain angular momentum distributions with inputs from the statistical model calculation. Comparison with another neighboring system, viz. 19 F + 175 Lu → 194 80 Hg 114 with nearly similar entrance-channel mass asymmetry, hints at the depletion of higher angular momenta after crossing of the Z=82 shell in the compound nucleus.

  5. Enriquecimento e alocação de 13C em plantas de eucalipto

    Directory of Open Access Journals (Sweden)

    Daniel Nolasco Machado

    2011-06-01

    Full Text Available Nas últimas décadas, a utilização de isótopos estáveis em várias áreas de pesquisa vem se destacando, como na análise de fluxos e rotas metabólicas, análise de efeitos de estresses em plantas e, em grande escala, no estudo da matéria orgânica do solo (MOS. Estudos de alterações e dinâmica da MOS usando a variação da abundância natural do 13C requerem mudanças na razão isotópica do C. Quando não existe essa possibilidade, uma das alternativas é enriquecer o material vegetal (planta com 13C, via fixação de 13CO2, de modo que a razão isotópica seja distinta daquela da MOS original. O objetivo deste trabalho foi investigar a magnitude e a homogeneidade do enriquecimento em 13C em diferentes componentes da planta de eucalipto. No processo de marcação, três plantas de eucalipto, com 4 meses de idade, cultivadas em solução nutritiva foram expostas a uma atmosfera enriquecida com 13CO2, em uma câmara de vidro (448 dm³, com temperatura em torno de 24 ºC. A concentração de CO2 e a razão 13C/12C foram monitoradas por um espectrômetro de massa de razão isotópica (IRMS em amostras de ar retiradas ao longo do processo (126 dias com três pulsos de 13CO2 semanais. Após o período de marcação, as plantas foram separadas em folha (folha-fonte e folha-dreno, galho, casca, lenho e raiz e analisadas em IRMS. O resultado foi expresso em partes por mil (‰ em relação ao padrão internacional de C denominado Pee-Dee Belemnite (PDB, obtendo-se a δ13C PDB delas: folha-fonte (828,07 ‰, folha-dreno (645,72 ‰, galho (672,49 ‰, casca (691,86 ‰, lenho (632,02 ‰ e raiz (536,55 ‰. O padrão de alocação e enriquecimento de 13C entre os componentes das plantas foi homogêneo, embora com diferenças numéricas da ordem de 291 ‰ na δ13C PDB. As plantas de eucalipto mantiveram alta taxa de absorção de CO2 e, consequentemente, alta taxa fotossintética em concentrações de CO2 muito acima (180,4 mmol L-1 - 7

  6. Design principles and theory of paramagnetic fluorine-labelled lanthanide complexes as probes for (19)F magnetic resonance: a proof-of-concept study.

    Science.gov (United States)

    Chalmers, Kirsten H; De Luca, Elena; Hogg, Naomi H M; Kenwright, Alan M; Kuprov, Ilya; Parker, David; Botta, Mauro; Wilson, J Ian; Blamire, Andrew M

    2010-01-04

    The synthesis and spectroscopic properties of a series of CF(3)-labelled lanthanide(III) complexes (Ln=Gd, Tb, Dy, Ho, Er, Tm) with amide-substituted ligands based on 1,4,7,10-tetraazacyclododecane are described. The theoretical contributions of the (19)F magnetic relaxation processes in these systems are critically assessed and selected volumetric plots are presented. These plots allow an accurate estimation of the increase in the rates of longitudinal and transverse relaxation as a function of the distance between the Ln(III) ion and the fluorine nucleus, the applied magnetic field, and the re-rotational correlation time of the complex, for a given Ln(III) ion. Selected complexes exhibit pH-dependent chemical shift behaviour, and a pK(a) of 7.0 was determined in one example based on the holmium complex of an ortho-cyano DO3A-monoamide ligand, which allowed the pH to be assessed by measuring the difference in chemical shift (varying by over 14 ppm) between two (19)F resonances. Relaxation analyses of variable-temperature and variable-field (19)F, (17)O and (1)H NMR spectroscopy experiments are reported, aided by identification of salient low-energy conformers by using density functional theory. The study of fluorine relaxation rates, over a field range of 4.7 to 16.5 T allowed precise computation of the distance between the Ln(III) ion and the CF(3) reporter group by using global fitting methods. The sensitivity benefits of using such paramagnetic fluorinated probes in (19)F NMR spectroscopic studies are quantified in preliminary spectroscopic and imaging experiments with respect to a diamagnetic yttrium(III) analogue.

  7. 13C mixed triglyceride breath test: a noninvasive method to assess lipase activity in children.

    Science.gov (United States)

    van Dijk-van Aalst, K; Van Den Driessche, M; van Der Schoor, S; Schiffelers, S; van't Westeinde, T; Ghoos, Y; Veereman-Wauters, G

    2001-05-01

    Results from the 13C mixed triglyceride (MTG) breath test correlate with duodenal lipase activity in adults. This noninvasive test is a potential screening and diagnostic tool for children with fat malabsorption. The aim of this study was to adapt the methodology of the MTG breath test to study test meals and sampling methods and to define normal values for healthy children of all age groups; premature and full-term infants have similar pancreatic lipase deficiencies. After parental consent was obtained, 12 premature infants ( 2 kg), 12 full-term infants (1-6 months old), 20 children (3-10 years old), and 20 teenagers (11-17 years old) were tested. All children were thriving well, had no gastrointestinal or respiratory problems, and had not received any medication that contained natural 13C. For the premature and full-term infants, a formula was prepared that had a low and stable natural 13C content mixed with 100 mg 13C-labeled MTG (1,3-distearyl, 2-[13C-carboxyl] octanoyl glycerol) and 1 g polyethylene-glycol 3350. The best accepted test meal for children over 3 years old was a slice of white bread with 5 g butter and 15 g chocolate paste, mixed with 250 mg 13C-labeled MTG, and a glass of 100 mL whole-fat milk. Children over 3 years old were able to blow through a straw in a vacutainer for collecting the breath samples. In children under 3 years old, expired air was collected by aspirating breath via a nasal prong. Carbon dioxide production was calculated according to weight, age, and sex. For healthy pediatric control participants, the mean values for cumulative excretion of 13CO2 as a percentage of the administered dose after 6 hours were 23.9 +/- 5.2% in premature infants, 31.9 +/- 7.7% in full-term infants, 32.5 +/- 5.3% in children, and 28.0 +/- 5.4% in teenagers. The mean value for healthy adults is 35.6% with a lower reference limit of 22.8%. Age-specific test meals and breath-sampling techniques for the MTG breath test were defined. The mean values for

  8. Synthesis and applications of selectively {sup 13}C-labeled RNA

    Energy Technology Data Exchange (ETDEWEB)

    SantaLucia, J. Jr.; Shen, L.X.; Lewis, H.; Cai, Z.; Tinoci, I. Jr. [Univ. of California, Berkeley, CA (United States)

    1994-12-01

    Spectral overlap is a substantial problem in NMR studies of RNA molecules >30 nucleotides. To overcome this difficulty, we synthesized selectively {sup 13}C-labeled RNAs and adapted several isotope-edited two- and three-dimensional NMR experiments originally developed for protein studies. We optimized protocols for synthesis of multi-gram quantities of CTP, UTp, ATP, and GTP using a combination of synthetic organic and enzymatic methods. Uracil is prepared in 40 to 50% yield from {sup 13}C-cyanide in two steps. Using acetyl- tribenzoyl-ribose and standard chemistry uracil is then attached to the sugar (90% yield). The tribenzoyl-uridine intermediate is converted into uridine or cytidine quantitatively, depending on the deblocking protocol. Labeled purines are synthesized using simple pyrimidine precursors and reacting with {sup 13}C-formic acid (80% yield). Purine nucleosides are then synthesized using uridine phosphorylase and purine nucleoside phosphorylase. The nucleosides were converted to NMPs by treatment with POC1{sub 3} in triethylphosphate. We converted NMPs to NTPs by standard enzymatic methods. Selectively labeled RNAs were synthesized by run-off transcription using {sup 13}C-labeled NTPs. Several different strategies help solve over-lap problems in larger RNAs. Isotope-edited two-dimensional NMR experiments such as {omega}1-1/2 X-filtered NOESY simplify NMR spectra by dividing the normal NOESY spectrum into two subspectra-one involving NOEs from protons bound to {sup 12}C and one from protons bound to {sup 13}C. For example, we labeled A and U residues of a 34-nucleotide pseudoknot, and the {sup 12}C subspectrum of the 1/2 X-filtered NOESY contained NOEs only from G and C residues (along with adenine 2H); the {sup 13}C subspectrum contained NOEs only from A and U residues. Each subspectrum has less overlap than the NOESY of an unlabeled sample; the editing strategy allows each resonance to be identified by residue type (A, C, G, or U).

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

    Directory of Open Access Journals (Sweden)

    Yoshikazu Suzuki

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

  10. Decoupling of coral skeletal δ13C and solar irradiance over the past millennium caused by the oceanic Suess effect

    Science.gov (United States)

    Deng, Wenfeng; Chen, Xuefei; Wei, Gangjian; Zeng, Ti; Zhao, Jian-xin

    2017-02-01

    Many factors influence the seasonal changes in δ13C levels in coral skeletons; consequently, the climatic and environmental significance of such changes is complicated and controversial. However, it is widely accepted that the secular declining trend of coral δ13C over the past 200 years reflects the changes in the additional flux of anthropogenic CO2 from the atmosphere into the surface oceans. Even so, the centennial-scale variations, and their significance, of coral δ13C before the Industrial Revolution remain unclear. Based on an annually resolved coral δ13C record from the northern South China Sea, the centennial-scale variations of coral δ13C over the past millennium were studied. The coral δ13C and total solar irradiance (TSI) have a significant positive Pearson correlation and coupled variation during the Medieval Warm Period and Little Ice Age, when natural forcing controlled the climate and environment. This covariation suggests that TSI controls coral δ13C by affecting the photosynthetic activity of the endosymbiotic zooxanthellae over centennial timescales. However, there was a decoupling of the coral skeletal δ13C and TSI during the Current Warm Period, the period in which the climate and environment became linked to anthropogenic factors. Instead, coral δ13C levels have a significant Pearson correlation with both the atmospheric CO2 concentration and δ13C levels in atmospheric CO2. The correlation between coral δ13C and atmospheric CO2 suggests that the oceanic 13C Suess effect, caused by the addition of increasing amounts of anthropogenic 12CO2 to the surface ocean, has led to the decoupling of coral δ13C and TSI at the centennial scale.

  11. 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.

  12. A facile synthesis of δ-aminolevulinic acid (ALA) regio-selectively labeled with 13C and direct observation of enzymatic transformation from ALA to porphobilinogen (PBG)

    International Nuclear Information System (INIS)

    Kurumaya, Katsuyuki; Okazaki, Takeo; Seido, Nobuo; Akasaka, Yuzuru; Kawajiri, Yoshiki; Kajiwara, Masahiro; Kondo, Masao

    1989-01-01

    δ-Aminolevulinic acid (ALA), labeled with 13 C at position 1, 2, 3, 4, or 5, was synthesized from 13 C-labeled glycine, Meldrum's acid, or bromoacetate. The latter compounds were prepared from 13 C-sodium acetate or 13 C-acetic acid. Enzymatic transformation from ALA to porphobilinogen (PBG) was directly observed by 13 C-NMR. (author)

  13. Investigating tumor perfusion and metabolism using multiple hyperpolarized 13C compounds: HP001, pyruvate and urea

    DEFF Research Database (Denmark)

    von Morze, Cornelius; Larson, Peder E.Z.; Hu, Simon

    2012-01-01

    The metabolically inactive hyperpolarized agents HP001 (bis-1,1-(hydroxymethyl)-[1-13C]cyclopropane-d8) and urea enable a new type of perfusion magnetic resonance imaging based on a direct signal source that is background-free. The addition of perfusion information to metabolic information obtained...... (T1=95 s ex vivo, 32 s in vivo at 3 T) using a pulse sequence with balanced steady-state free precession and ramped flip angle over time for efficient utilization of the hyperpolarized magnetization and three-dimensional echo-planar spectroscopic imaging of urea copolarized with [1-13C...... of separate dynamic HP001 imaging and copolarized pyruvate/urea imaging were compared. A strong and significant correlation (R=0.73, P=.02) detected between the urea and HP001 data confirmed the value of copolarizing urea with pyruvate for simultaneous assessment of perfusion and metabolism....

  14. 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...

  15. 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.

  16. Analysis of Hydroperoxides in Solid Polyethylene by MAS (13)C NMR and EPR

    International Nuclear Information System (INIS)

    ASSINK, ROGER A.; CELINA, MATHIAS C.; DUNBAR, TIMOTHY D.; ALAM, TODD M.; CLOUGH, ROGER LEE; GILLEN, KENNETH T.

    1999-01-01

    13 C-enriched polyethylene was subjected to γ-irradiation in the presence of air at 25 and 80 C for total doses ranging from 71 to 355 kGy. Significant quantities of hydroperoxides were detected in the 25 C irradiated sample by 13 C magic angle spinning NMR spectroscopy. This method of detection was performed on the solid polymer and required no chemical derivatization or addition of solvent. The chemical stability and subsequent products of the hydroperoxide species were studied by annealing the irradiated samples in air at temperatures ranging from 22 to 110 C. A time-temperature superposition analysis provided an activation energy of 108 kJ/mol for the hydroperoxide decomposition process. The primary products of hydroperoxide decomposition were ketones and secondary alcohols with lesser amounts of acids and esters. EPR measurements suggest that the reactive hydroperoxide species reside in the amorphous phase of polyethylene, consistent with degradation occurring in the amorphous phase

  17. Calculation of the 13C NMR shieldings of the C0 2 complexes of aluminosilicates

    Science.gov (United States)

    Tossell, J. A.

    1995-04-01

    13C NMR shieldings have been calculated using the random-phase-approximation, localized-orbital local-origins version of ab initio coupled Hartree-Fuck perturbation theory for CO 2 and and for several complexes formed by the reaction of CO 2 with molecular models for aluminosilicate glasses, H 3TOT'H3 3-n, T,T' = Si,Al. Two isomeric forms of the CO 2-aluminosilicate complexes have been considered: (1) "CO 2-like" complexes, in which the CO 2 group is bound through carbon to a bridging oxygen and (2) "CO 3-like" complexes, in which two oxygens of a central CO 3 group form bridging bonds to the two TH 3 groups. The CO 2-like isomer of CO 2-H 3SiOSiH 3 is quite weakly bonded and its 13C isotropic NMR shielding is almost identical to that in free CO 2. As Si is progressively replaced by Al in the - H terminated aluminosilicate model, the CO 2-like isomers show increasing distortion from the free CO 2 geometry and their 13C NMR shieldings decrease uniformly. The calculated 13C shielding value for H 3AlO(CO 2)AlH 3-2 is only about 6 ppm larger than that calculated for point charge stabilized CO 3-2. However, for a geometry of H 3SiO(CO 2) AlH 3-1, in which the bridging oxygen to C bond length has been artificially increased to that found in the - OH terminated cluster (OH) 3SiO(CO 2)Al(OH) 3-1, the calculated 13C shielding is almost identical to that for free CO 2. The CO 3-like isomers of the CO 2-aluminosili-cate complexes show carbonate like geometries and 13C NMR shieldings about 4-9 ppm larger than those of carbonate for all T,T' pairs. For the Si,Si tetrahedral atom pair the CO 2-like isomer is more stable energetically, while for the Si,Al and Al,Al cases the CO 3-like isomer is more stable. Addition of Na + ions to the CO 3-2 or H 3AlO(CO 2)AlH 3-2 complexes reduces the 13C NMR shieldings by about 10 ppm. Complexation with either Na + or CO 2 also reduces the 29Si NMR shieldings of the aluminosilicate models, while the changes in 27Al shielding with Na + or CO 2

  18. Reconstructing past climate using a multi-specific 13C-approach

    Science.gov (United States)

    Ferrio, Juan Pedro; Aguilera, Mónica; Voltas, Jordi

    2010-05-01

    Carbon isotope composition (δ13C) in tree-rings has become routinely used in palaeoclimatic research for the assessment of changes in water availability in seasonally dry climates. Long tree-ring chronologies, however, are relatively scarce, whereas the original climate signal of wood δ13C is usually well preserved in fossil charcoal [1, 4] Accordingly, charcoal δ13C records are an alternative to classic dendroclimatology to characterize past changes in water availability (e.g. precipitation). In this work, we explore the potential for palaeoenvironmental research of two co-occuring Mediterranean species with contrasting strategies to cope with drought [2]: Aleppo pine (Pinus halepensis Mill.) and holm oak (Quercus ilex L.). We hypothesize that the differential sensitivity of pine and oak to climate variables can be exploited to refine palaeoclimate reconstructions based on δ13C in wood or charcoal. For this purpose, we put together published tree-core-δ13C data from 40 sites across Spain [2, 3] and new δ13C data from 15 sites where both species co-existed in mixed stands. The sites were selected to represent the range of variation in thermal and precipitation regimes for these species, while avoiding any correlation between precipitation and temperature across sites. Five dominant or codominant trees were selected per site, and microcores including the most recently formed tree rings were obtained with a Trephor tool [5]. Fragments were oven-dried at 60 ° C for 48 h and milled separately to a fine powder using a ball mill (Retsch MM301, Haan, Germany) for δ13C analysis. Current meteorological data (monthly estimates of air mean temperature (minimum, mean and maximum), precipitation and solar radiation) was obtained from the Digital Climatic Atlas of the Iberian Peninsula (http://opengis.uab.es/wms/iberia/index.htm) (spatial resolution of 200 m). A family of models (either linear or exponential) best predicting monthly and annual precipitation from δ13C

  19. Direct observation of glycogen synthesis in human muscle with 13C NMR

    International Nuclear Information System (INIS)

    Jue, T.; Rothman, D.L.; Shulman, G.I.; Tavitian, B.A.; DeFronzo, R.A.; Shulman, R.G.

    1989-01-01

    On the basis of previous indirect measurements, skeletal muscle has been implicated as the major site of glucose uptake and it has been suggested that muscle glycogen formation is the dominant pathway. However, direct measurements of the rates of glycogen synthesis have not been possible by previous techniques. The authors have developed 13 C NMR methods to measure directly the rate of human muscle glycogen formation from infused, isotopically labeled [1- 13 C]glucose. They show that under conditions of imposed hyperglycemia and hyperinsulinemia, a majority of the infused glucose was converted to muscle glycogen in a normal man. This directly shows that muscle is the major site of glucose disposal under these conditions, and provides quantitation of the glucose flux to muscle glycogen

  20. Computer-aided structure analysis. Structure identification by infrared and /sup 13/C NMR measurements

    Energy Technology Data Exchange (ETDEWEB)

    Szalontai, G; Simon, Z; Csapo, Z; Farkas, M; Pfeifer, Gy [Nehezvegyipari Kutato Intezet, Veszprem (Hungary)

    1980-01-01

    The results obtained from the computer-aided interpretation of /sup 13/C NMR and IR spectra using the artificial intelligence approach are presented. In its present state the output of the system is a list of functional groups which are resonable candidates for the final structural isomers. The input requires empirical formula, /sup 13/C NMR data (off resonance data also) and IR spectral data. The confirmation of the presence of a functional group is based on comparison of the experimental data with the spectral properties of functional groups stored in a property matrix. If the molecular weight of the compounds studied is less or equal 500, the output contains usually 1.5-2.5 times more groups than really present, in most cases without the loss of the real ones.

  1. 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.

  2. /sup 13/C NMR spectra and electron conduction in 4-substituted diphenylamines

    Energy Technology Data Exchange (ETDEWEB)

    Filimonov, V.D.; Kogan, R.M.; Tverdokhlebova, N.E.; Shcherbakov, V.V.; Kushnarev, D.F.; Kalabin, G.A.

    1986-07-10

    The /sup 13/C NMR spectra were recorded for a series of 4-X-diphenylamines, and correlations equations relating the /sup 13/C NMR chemical shifts of the C/sup 1/ and C/sup 4/ positions to the electronic characteristics of the substituent X were obtained. It was established that the conduction of the substituted ring in the 4-X-diphenylamines is practically the same as in 4-X-biphenyls. Joint analysis of the spectral characteristics of the diphenylamines, biphenyls, N-substituted anilines, and carbazoles made it possible to conclude that the increased transmission characteristics of the diphenylamines are determined by the conformational mobility of the two benzene rings and by the unidirectional effect of changes in the introduction and resonance factors with variation in the substituent X.

  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. Large old trees influence patterns of delta13C and delta15N in forests.

    Science.gov (United States)

    Weber, Pascale; Bol, Roland; Dixon, Liz; Bardgett, Richard D

    2008-06-01

    Large old trees are the dominant primary producers of native pine forest, but their influence on spatial patterns of soil properties and potential feedback to tree regeneration in their neighbourhood is poorly understood. We measured stable isotopes of carbon (delta(13)C) and nitrogen (delta(15)N) in soil and litter taken from three zones of influence (inner, middle and outer zone) around the trunk of freestanding old Scots pine (Pinus sylvestris L.) trees, to determine the trees' influence on below-ground properties. We also measured delta(15)N and delta(13)C in wood cores extracted from the old trees and from regenerating trees growing within their three zones of influence. We found a significant and positive gradient in soil delta(15)N from the inner zone, nearest to the tree centre, to the outer zone beyond the tree crown. This was probably caused by the higher input of (15)N-depleted litter below the tree crown. In contrast, the soil delta(13)C did not change along the gradient of tree influence. Distance-related trends, although weak, were visible in the wood delta(15)N and delta(13)C of regenerating trees. Moreover, the wood delta(15)N of small trees showed a weak negative relationship with soil N content in the relevant zone of influence. Our results indicate that large old trees control below-ground conditions in their immediate surroundings, and that stable isotopes might act as markers for the spatial and temporal extent of these below-ground effects. John Wiley & Sons, Ltd

  5. 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.

  6. 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

  7. Changes in chemical composition of litter during decomposition: a review of published 13C NMR spectra

    Czech Academy of Sciences Publication Activity Database

    Cepáková, Šárka; Frouz, Jan

    2015-01-01

    Roč. 15, č. 3 (2015), s. 805-815 ISSN 0718-9516 Grant - others:GAJU(CZ) GAJU/04-146/2013P; GA ČR(CZ) GAP504/12/1288 Program:GA Institutional support: RVO:60077344 Keywords : 13C CPMAS NMR * litter decomposition * litter quality * soil organic matter Subject RIV: DF - Soil Science Impact factor: 1.600, year: 2015

  8. 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.

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  10. 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

  11. 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.

  12. OpenFLUX: efficient modelling software for 13C-based metabolic flux analysis

    Directory of Open Access Journals (Sweden)

    Nielsen Lars K

    2009-05-01

    Full Text Available Abstract Background The quantitative analysis of metabolic fluxes, i.e., in vivo activities of intracellular enzymes and pathways, provides key information on biological systems in systems biology and metabolic engineering. It is based on a comprehensive approach combining (i tracer cultivation on 13C substrates, (ii 13C labelling analysis by mass spectrometry and (iii mathematical modelling for experimental design, data processing, flux calculation and statistics. Whereas the cultivation and the analytical part is fairly advanced, a lack of appropriate modelling software solutions for all modelling aspects in flux studies is limiting the application of metabolic flux analysis. Results We have developed OpenFLUX as a user friendly, yet flexible software application for small and large scale 13C metabolic flux analysis. The application is based on the new Elementary Metabolite Unit (EMU framework, significantly enhancing computation speed for flux calculation. From simple notation of metabolic reaction networks defined in a spreadsheet, the OpenFLUX parser automatically generates MATLAB-readable metabolite and isotopomer balances, thus strongly facilitating model creation. The model can be used to perform experimental design, parameter estimation and sensitivity analysis either using the built-in gradient-based search or Monte Carlo algorithms or in user-defined algorithms. Exemplified for a microbial flux study with 71 reactions, 8 free flux parameters and mass isotopomer distribution of 10 metabolites, OpenFLUX allowed to automatically compile the EMU-based model from an Excel file containing metabolic reactions and carbon transfer mechanisms, showing it's user-friendliness. It reliably reproduced the published data and optimum flux distributions for the network under study were found quickly ( Conclusion We have developed a fast, accurate application to perform steady-state 13C metabolic flux analysis. OpenFLUX will strongly facilitate and

  13. {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.

  14. 13C evidence for dietary habits of prehistoric man in Denmark

    International Nuclear Information System (INIS)

    Tauber, H.

    1981-01-01

    The 13 C fractionation pattern which is affected by the type of metabolism used by plants to fix CO 2 and differs in marine and terrestrial plants, has been used to investigate the dietary habits of prehistoric man in northwestern Europe. The results show that whereas Danish Mesolithic man lived on a diet dominated by sea food, in the Neolithic the human diet consisted predominantly of terrestrial food. (U.K.)

  15. 13C NMR and stereochestry of 1-β-phenylethylcyclohexanol derivatives obtained by synthesis

    International Nuclear Information System (INIS)

    Antunes, O.A.C.; Braz Filho, R.

    1986-01-01

    1-β-Phenylethylcyclohexanol derivatives substituted in position 2 have been synthesized and analysed by 13 C-NMR spectroscopy. Their stereochemistry have been considered as cis (hydroxyl in C-1 and substituent in C-2) which is in agreement with the pertinent literature. Derivatives obtained were 2-β-phenylethyl-2-allycyclohexanol, 1-β-phenylethyl-2-methylcyclohexanol, 7a-β-phenylethylperhy-drobenzo (b) furan, and 1-β-phenylethyl-2-β-hydroxyethylcyclohexanol. (author) [pt

  16. d13C Signatures of Flora, Macrofauna and Sediment of a Mangrove ...

    African Journals Online (AJOL)

    Mangrove organic carbon (d13C±SD = - 27.97±0.25) was found to be an important component of the sediment organic matter except at the marine fringe zone (d13C±SD = - 17.26±0.83). The areal distribution of d13C values show that the marine fringe zone was rich in organic carbon of marine origin. The terrestrial fringe ...

  17. High-throughput and homogeneous 13C-labelling of plant material for fair carbon accounting

    International Nuclear Information System (INIS)

    Slaets, J.I.F.; Resch, C.; Mayr, L.; Weltin, G.; Heiling, M.; Gruber, R.; Dercon, G.

    2016-01-01

    With growing political acknowledgement of the anthropogenic drivers and consequences of climate change, the development of carbon accounting mechanisms is essential for fair greenhouse gas emission mitigation policies. Therefore, carbon storage and emission must be accurately quantified. Plant material labelled with 13 C can be used to measure carbon storage in soil and carbon losses via CO 2 emission to the atmosphere from various cropping practices through in situ and incubation experiments.

  18. 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.

  19. Chemienzymatic synthesis of Uridine. Nucleotides labeled with [15N] and [13C

    DEFF Research Database (Denmark)

    Gilles, Anne-Marie; Cristea, Ioan; Palibroda, Nicolae

    1995-01-01

    +necessary for the oxidation of glucose 6-phosphate and 6-phosphogluconate was recycled by glutamate dehydrogenase and excess of ammonia and a-oxoglutarate. Despite the number and complexity of the enzymatic steps, the synthesis of [15N,13C]UTP is straightforward with an overall yield exceeding 60%. This method, extended...... and diversified to the synthesis of all natural ribonucleotides, is a more economical alternative for obtaining nucleic acids for structural analysis by heteronuclear NMR spectroscopy....

  20. Preparation of 2H- and 13C-labelled precursors of 2-hydroxy-1, 3-butadiene

    International Nuclear Information System (INIS)

    Turecek, F.

    1987-01-01

    2-exo-Vinylbicyclo[2.2.1]hept-5-en-2-ols, specifically labelled with 2 H at C-3 and in the vinyl group were prepared from bicyclo[2.2.1]hept-5-en-2-one in several steps. [4- 13 C]oct-1-en-3-one was prepared in five steps from 13 CO 2 . These compounds serve as precursors for the preparation of specifically labelled neutral and ionized 2-hydroxy-1, 3-butadienes. (author)

  1. Assessing microbial utilization of free versus sorbed Alanine by using position-specific 13C labeling and 13C-PLFA analysis

    Science.gov (United States)

    Herschbach, Jennifer; Apostel, Carolin; Spielvogel, Sandra; Kuzyakov, Yakov; Dippold, Michaela

    2016-04-01

    Microbial utilization is a key transformation process of soil organic matter (SOM). Sorption of low molecular weight organic substances (LMWOS) to soil mineral surfaces blocks or delays microbial uptake and therefore mineralization of LMWOS to CO2, as well as all other biochemical transformations. We used position-specific labeling, a tool of isotope applications novel to soil science, combined with 13C-phospholipid fatty acid (PLFA) analysis, to assess microbial utilization of sorbed and non-sorbed Alanine in soil. Alanine has various functional groups enabling different sorption mechanisms via its positive charge (e.g. to clay minerals by cation exchange), as well as via its negative charge (e.g. to iron oxides by ligand exchange). To assess changes in the transformation pathways caused by sorption, we added uniformly and position-specifically 13C and 14C labeled Alanine to the Ap of a loamy Luvisol in a short-term (10 days) incubation experiment. To allow for sorption of the tracer solution to an aliquot of this soil, microbial activity was minimized in this subsample by sterilizing the soil by γ-radiation. After shaking, the remaining solutions were filtered and the non-sorbed Alanine was removed with Millipore water and then added to non-sterilized soil. For the free Alanine treatment, solutions with Alanine of similar amount and isotopic composition were prepared, added to the soil and incubated as well. The respired CO2 was trapped in NaOH and its 14C-activity was determined at increasing times intervals. Microbial utilization of Alanine's individual C positions was evaluated in distinct microbial groups classified by 13C-PLFA analysis. Sorption to soil minerals delayed respiration to CO2 and reduced initial respiration rate by 80%. Irrespective of sorption, the highest amount was respired from the carboxylic position (C-1), whereas the amino-bound (C-2) and the methylic position (C-3) were preferentially incorporated into PLFA of microorganisms due to the

  2. Determination of the δ13C (per mille) isotopic rate of the Brazilian beer pilsen type

    International Nuclear Information System (INIS)

    Rossete, Alexssandra L.R.M.; Bendassolli, Jose Albertino; Lopes, Fabio; Martinelli, Luiz Antonio

    2002-01-01

    Beer has been consumed in Brazil since the XIX century. However, at that time, this beverage was imported from England, and the first Brazilian breweries just appeared at the end of the XX century. Basically, beer is made from: malt of barley, Humulus lupulus, water and yeast. In this work, twenty brands of national beer (Pilsen type), and also two different cereals, barley, a C3 metabolism plant, corn, a C4 plant, were analysed to determine their isotope composition δ 13 C (per mille) utilizing a mass spectrometer Delta Plus Finigam and Anca S.L. An aliquot of each sample was transferred using a capillary of glass to a tin capsule contends a small amount of sorbitol. The isotope compositions, δ 13 C, of barley and corn samples determined were -27.2 and -11.5 per mille, respectively. These results were used to calculate the equation of mixture model. Considering the beer samples, the δ 13 C ranged from -18.3 to -23.1 per mille; this result means that the percentage of C3 plant is from 43.3 to 73.9 per mille. In this manner, it is possible to concluded that all beer samples has malted cereals (C4 plant), as far as the low values of C3 plants were presented in these samples as shown through the equation of mixtures model. (author)

  3. Biosynthetic preparation of L-[13C]- and [15N]glutamate by Brevibacterium flavum

    International Nuclear Information System (INIS)

    Walker, T.E.; London, R.E.

    1987-01-01

    The biosynthesis of isotopically labeled L-glutamic acid by the microorganism Brevibacterium flavum was studied with a variety of carbon-13-enriched precursors. The purpose of this study was twofold: (i) to develop techniques for the efficient preparation of labeled L-glutamate with a variety of useful labeling patterns which can be used for other metabolic studies, and (ii) to better understand the metabolic events leading to label scrambling in these strains. B. flavum, which is used commercially for the production of monosodium glutamate, has the capability of utilizing glucose or acetate as a sole carbon source, and important criterion from the standpoint of developing labeling strategies. Unfortunately, singly labeled glucose precursors lead to excessive isotopic dilution which reduces their usefulness. Studies with [3- 13 C]pyruvate indicate that this problem can in principle be overcome by using labeled three-carbon precursors; however, conditions could not be found which would lead to an acceptable yield of isotopically labeled L-glutamate. In contrast, [1- 13 C]- or [2- 13 C]acetate provides relatively inexpensive, readily available precursors for the production of selectively labeled, high enriched L-glutamate. The preparation of L-[ 15 N]glutamate from [ 15 N]ammonium sulfate was carried out and is a very effective labeling strategy. Analysis of the isotopic distribution in labeled glutamate provides details about the metabolic pathways in these interesting organisms

  4. The assesment of the food quality by 13 C isotope ratio mass spectrometry

    International Nuclear Information System (INIS)

    Cuna, Stela; Cuna, Cornel

    2001-01-01

    Carbon 13 analysis can be a key analytical technique used in the fight to detect undeclared addition of low cost adulterants to high value foods. The natural abundance of 13 C in food is related to how the plant fix the carbon during photosynthesis. Plants that use a C3 photosynthetic cycle discriminate against 13 C more than plants with C4 cycle. We developed a method for analysis of 13 C isotope in organic samples. Because of instrumental requirements carbon must be converted to CO 2 for stable isotope ratio measurements. Conversion of organic samples to CO 2 was accomplished by combustion in an excess oxygen atmosphere. This technique involves the combustion of individual samples in sealed, evacuated quartz tubes containing CuO as the oxygen source. Because each sample is prepared in its own container, there is no chance for memory effects. The method was tested for sensitivity (the smallest increment of the isotope ratio that must be detected with confidence), sample size (the minimum quantity of a pure molecular species available to achieve the desired accuracy) and precision. The method was utilised for the detection of a synthetic flavour from natural one, namely the natural oil bitter almond from the synthetic benzaldehyde. The method can be validated for the detection or establishment of authenticity in food products. (authors)

  5. 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)

  6. Improved CRDS δ13C Stability Through New Calibration Application For CO2 And CH4

    Science.gov (United States)

    Rella, Chris; Arata, Caleb; Saad, Nabil; Leggett, Graham; Miles, Natasha; Richardson, Scott; Davis, Ken

    2015-04-01

    Stable carbon isotope ratio measurements of CO2 and CH4 provide valuable insight into global and regional sources and sinks of the two most important greenhouse gases. Methodologies based on Cavity Ring-Down Spectroscopy (CRDS) have been developed and are capable of delivering δ13C measurements with a precision better than 0.12 permil for CO2 and 0.4 permil for CH4 (1 hour window, 5 minute average). Here we present a method to further improve this measurement stability. We have developed a two-point calibration method which corrects for δ13C drift due to a dependence on carbon species concentration. This method calibrates for both carbon species concentration as well as δ13C. In addition, we further demonstrate that this added stability is especially valuable when using carbon isotope data in linear regression models such as Keeling plots, where even small amounts of error can be magnified to give inconclusive results. Furthermore, we show how this method is used to validate multiple instruments simultaneously and can be used to create the standard samples needed for field calibrations.

  7. Quantified pH imaging with hyperpolarized (13) C-bicarbonate.

    Science.gov (United States)

    Scholz, David Johannes; Janich, Martin A; Köllisch, Ulrich; Schulte, Rolf F; Ardenkjaer-Larsen, Jan H; Frank, Annette; Haase, Axel; Schwaiger, Markus; Menzel, Marion I

    2015-06-01

    Because pH plays a crucial role in several diseases, it is desirable to measure pH in vivo noninvasively and in a spatially localized manner. Spatial maps of pH were quantified in vitro, with a focus on method-based errors, and applied in vivo. In vitro and in vivo (13) C mapping were performed for various flip angles for bicarbonate (BiC) and CO2 with spectral-spatial excitation and spiral readout in healthy Lewis rats in five slices. Acute subcutaneous sterile inflammation was induced with Concanavalin A in the right leg of Buffalo rats. pH and proton images were measured 2 h after induction. After optimizing the signal to noise ratio of the hyperpolarized (13) C-bicarbonate, error estimation of the spectral-spatial excited spectrum reveals that the method covers the biologically relevant pH range of 6 to 8 with low pH error (< 0.2). Quantification of pH maps shows negligible impact of the residual bicarbonate signal. pH maps reflect the induction of acute metabolic alkalosis. Inflamed, infected regions exhibit lower pH. Hyperpolarized (13) C-bicarbonate pH mapping was shown to be sensitive in the biologically relevant pH range. The mapping of pH was applied to healthy in vivo organs and interpreted within inflammation and acute metabolic alkalosis models. © 2014 Wiley Periodicals, Inc.

  8. SUMOFLUX: A Generalized Method for Targeted 13C Metabolic Flux Ratio Analysis

    Science.gov (United States)

    Kogadeeva, Maria

    2016-01-01

    Metabolic fluxes are a cornerstone of cellular physiology that emerge from a complex interplay of enzymes, carriers, and nutrients. The experimental assessment of in vivo intracellular fluxes using stable isotopic tracers is essential if we are to understand metabolic function and regulation. Flux estimation based on 13C or 2H labeling relies on complex simulation and iterative fitting; processes that necessitate a level of expertise that ordinarily preclude the non-expert user. To overcome this, we have developed SUMOFLUX, a methodology that is broadly applicable to the targeted analysis of 13C-metabolic fluxes. By combining surrogate modeling and machine learning, we trained a predictor to specialize in estimating flux ratios from measurable 13C-data. SUMOFLUX targets specific flux features individually, which makes it fast, user-friendly, applicable to experimental design and robust in terms of experimental noise and exchange flux magnitude. Collectively, we predict that SUMOFLUX's properties realistically pave the way to high-throughput flux analyses. PMID:27626798

  9. Applications of stable isotopes of 2H, 13C and 15N to clinical problems

    International Nuclear Information System (INIS)

    Klein, P.D.; Szczepanik, P.A.; Hachey, D.L.

    1974-01-01

    The function of the Argonne Program is to provide synthetic, analytical instrumental capability in a core facility for the clinical investigator who needs to use 2 H, 13 C, or 15 N labelled compounds for metabolic or clinical research on pregnant women, newborn infants, young children, or for mass screening. To carry out such application development, there were six stages which were recurrent steps in every application. Five fundamental strategies should be adopted to establish the use of stable isotopes in clinical work. The instrument required for measurements was a combined gas chromatograph-mass spectrometer, and its use was schematically illustrated. Some of the successful experiences with compounds labelled by stable isotopes, such as deuterium labelled chenodeoxycholic acid, and respective 13 C and 15 N-labelled glycine were described. Deutrium labelled bile acid enabled easy and safe determination of the size of the bile acid pool and the replacement rate, providing clearer diagnoses for cholestatic liver disease and gallstones. 13 C and 15 N labelled compounds were used in clinical studies, of children with genetic disorders of amino acid metabolism, i.e., non ketotic hyperflycinemia, B 12 -responsive methyl malonic acidemia, and Lesch-Nyhan syndrome. 15 N-labelled glycine was also studied in a child with Lesch-Nyhan syndrome. (Mukohata, S.)

  10. Direct 13C-detected NMR experiments for mapping and characterization of hydrogen bonds in RNA

    International Nuclear Information System (INIS)

    Fürtig, Boris; Schnieders, Robbin; Richter, Christian; Zetzsche, Heidi; Keyhani, Sara; Helmling, Christina; Kovacs, Helena; Schwalbe, Harald

    2016-01-01

    In RNA secondary structure determination, it is essential to determine whether a nucleotide is base-paired and not. Base-pairing of nucleotides is mediated by hydrogen bonds. The NMR characterization of hydrogen bonds relies on experiments correlating the NMR resonances of exchangeable protons and can be best performed for structured parts of the RNA, where labile hydrogen atoms are protected from solvent exchange. Functionally important regions in RNA, however, frequently reveal increased dynamic disorder which often leads to NMR signals of exchangeable protons that are broadened beyond 1 H detection. Here, we develop 13 C direct detected experiments to observe all nucleotides in RNA irrespective of whether they are involved in hydrogen bonds or not. Exploiting the self-decoupling of scalar couplings due to the exchange process, the hydrogen bonding behavior of the hydrogen bond donor of each individual nucleotide can be determined. Furthermore, the adaption of HNN-COSY experiments for 13 C direct detection allows correlations of donor–acceptor pairs and the localization of hydrogen-bond acceptor nucleotides. The proposed 13 C direct detected experiments therefore provide information about molecular sites not amenable by conventional proton-detected methods. Such information makes the RNA secondary structure determination by NMR more accurate and helps to validate secondary structure predictions based on bioinformatics.

  11. Human hepatic carbohydrate metabolism. Dynamic observation using 13C MRS without proton decoupling

    International Nuclear Information System (INIS)

    Ikehira, H.; Obata, T.; Koga, M.; Yoshida, K.

    1997-01-01

    Purpose: Dynamic natural-abundance 13 C MR spectroscopy (MRS) studies without proton decoupling were performed in the human liver using commercial 1.5 T MR equipment. Material and methods: A single tuned custom-made circular surface coil with an OD of 20 cm operating at 16.04 MHz was used for the 13 C study. Seventy-five grams of glucose dissolved in water was administered for the natural-abundance 13 C-MRS dynamic study which lasted for approximately 40 to 60 min. Data acquisition was broken into 20-min and 1.7-min blocks. Localized proton shimming with a whole-body coil was performed with sufficient volume to include the observing area of the surface coil; the line width of the water signal was less than 20 Hz. Results and Conclusion: The glucose and glycogen spectra were clearly visible at 80 to 120 ppm after oral administration of the glucose solution. These data demonstrate that dynamic hepatic carbohydrate metabolism can be observed with commercially available MR equipment. Given that the human hepatic glycogen pool reaches maximum level within less than 10 min, this technique should provide a direct diagnosis of hepatic carbohydrate metabolic disorders. (orig.)

  12. Application of 13C-stable isotope probing to identify RDX-degrading microorganisms in groundwater

    International Nuclear Information System (INIS)

    Cho, Kun-Ching; Lee, Do Gyun; Roh, HyungKeun; Fuller, Mark E.; Hatzinger, Paul B.; Chu, Kung-Hui

    2013-01-01

    We employed stable isotope probing (SIP) with 13 C-labeled hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to identify active microorganisms responsible for RDX biodegradation in groundwater microcosms. Sixteen different 16S rRNA gene sequences were derived from microcosms receiving 13 C-labeled RDX, suggesting the presence of microorganisms able to incorporate carbon from RDX or its breakdown products. The clones, residing in Bacteroidia, Clostridia, α-, β- and δ-Proteobacteria, and Spirochaetes, were different from previously described RDX degraders. A parallel set of microcosms was amended with cheese whey and RDX to evaluate the influence of this co-substrate on the RDX-degrading microbial community. Cheese whey stimulated RDX biotransformation, altered the types of RDX-degrading bacteria, and decreased microbial community diversity. Results of this study suggest that RDX-degrading microorganisms in groundwater are more phylogenetically diverse than what has been inferred from studies with RDX-degrading isolates. Highlights: •SIP identified sixteen groundwater bacteria capable of using RDX and/or its metabolites as a carbon source. •The RDX degraders in groundwater are phylogenetically diverse and different from known RDX degraders. •Cheese whey induced community shift and altered diversity of the RDX-degrading microorganisms over time. -- RDX-degrading bacteria in contaminated groundwater, identified by SIP with 13 C-labeled RDX, are phylogenetically diverse and different from known RDX degraders

  13. (13)C-metabolic flux analysis in S-adenosyl-L-methionine production by Saccharomyces cerevisiae.

    Science.gov (United States)

    Hayakawa, Kenshi; Kajihata, Shuichi; Matsuda, Fumio; Shimizu, Hiroshi

    2015-11-01

    S-Adenosyl-L-methionine (SAM) is a major biological methyl group donor, and is used as a nutritional supplement and prescription drug. Yeast is used for the industrial production of SAM owing to its high intracellular SAM concentrations. To determine the regulation mechanisms responsible for such high SAM production, (13)C-metabolic flux analysis ((13)C-MFA) was conducted to compare the flux distributions in the central metabolism between Kyokai no. 6 (high SAM-producing) and S288C (control) strains. (13)C-MFA showed that the levels of tricarboxylic acid (TCA) cycle flux in SAM-overproducing strain were considerably increased compared to those in the S228C strain. Analysis of ATP balance also showed that a larger amount of excess ATP was produced in the Kyokai 6 strain because of increased oxidative phosphorylation. These results suggest that high SAM production in Kyokai 6 strains could be attributed to enhanced ATP regeneration with high TCA cycle fluxes and respiration activity. Thus, maintaining high respiration efficiency during cultivation is important for improving SAM production. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  14. Pressure-dependent {sup 13}C chemical shifts in proteins: origins and applications

    Energy Technology Data Exchange (ETDEWEB)

    Wilton, David J. [University of Sheffield, Department of Molecular Biology and Biotechnology (United Kingdom); Kitahara, Ryo [Ritsumeikan University, College of Pharmaceutical Sciences (Japan); Akasaka, Kazuyuki [Kinki University, Department of Biotechnological Science, School of Biology-Oriented Science and Technology (Japan); Williamson, Mike P. [University of Sheffield, Department of Molecular Biology and Biotechnology (United Kingdom)], E-mail: m.williamson@sheffield.ac.uk

    2009-05-15

    Pressure-dependent {sup 13}C chemical shifts have been measured for aliphatic carbons in barnase and Protein G. Up to 200 MPa (2 kbar), most shift changes are linear, demonstrating pressure-independent compressibilities. CH{sub 3}, CH{sub 2} and CH carbon shifts change on average by +0.23, -0.09 and -0.18 ppm, respectively, due to a combination of bond shortening and changes in bond angles, the latter matching one explanation for the {gamma}-gauche effect. In addition, there is a residue-specific component, arising from both local compression and conformational change. To assess the relative magnitudes of these effects, residue-specific shift changes for protein G were converted into structural restraints and used to calculate the change in structure with pressure, using a genetic algorithm to convert shift changes into dihedral angle restraints. The results demonstrate that residual {sup 13}C{alpha} shifts are dominated by dihedral angle changes and can be used to calculate structural change, whereas {sup 13}C{beta} shifts retain significant dependence on local compression, making them less useful as structural restraints.

  15. {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)

  16. 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

  17. 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

  18. 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

  19. Trans and surface membrane bound zervamicin IIB: 13C-MAOSS-NMR at high spinning speed

    International Nuclear Information System (INIS)

    Raap, J.; Hollander, J.; Ovchinnikova, T. V.; Swischeva, N. V.; Skladnev, D.; Kiihne, S.

    2006-01-01

    Interactions between 15 N-labelled peptides or proteins and lipids can be investigated using membranes aligned on a thin polymer film, which is rolled into a cylinder and inserted into the MAS-NMR rotor. This can be spun at high speed, which is often useful at high field strengths. Unfortunately, substrate films like commercially available polycarbonate or PEEK produce severe overlap with peptide and protein signals in 13 C-MAOSS NMR spectra. We show that a simple house hold foil support allows clear observation of the carbonyl, aromatic and C α signals of peptides and proteins as well as the ester carbonyl and choline signals of phosphocholine lipids. The utility of the new substrate is validated in applications to the membrane active peptide zervamicin IIB. The stability and macroscopic ordering of thin PC10 bilayers was compared with that of thicker POPC bilayers, both supported on the household foil. Sidebands in the 31 P-spectra showed a high degree of alignment of both the supported POPC and PC10 lipid molecules. Compared with POPC, the PC10 lipids are slightly more disordered, most likely due to the increased mobilities of the shorter lipid molecules. This mobility prevents PC10 from forming stable vesicles for MAS studies. The 13 C-peptide peaks were selectively detected in a 13 C-detected 1 H-spin diffusion experiment. Qualitative analysis of build-up curves obtained for different mixing times allowed the transmembrane peptide in PC10 to be distinguished from the surface bound topology in POPC. The 13 C-MAOSS results thus independently confirms previous findings from 15 N spectroscopy [Bechinger, B., Skladnev, D.A., Ogrel, A., Li, X., Rogozhkina, E.V., Ovchinnikova, T.V., O'Neil, J.D.J. and Raap, J. (2001) Biochemistry, 40, 9428-9437]. In summary, application of house hold foil opens the possibility of measuring high resolution 13 C-NMR spectra of peptides and proteins in well ordered membranes, which are required to determine the secondary and

  20. 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.

  1. 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

  2. Two-Scale 13C Metabolic Flux Analysis for Metabolic Engineering.

    Science.gov (United States)

    Ando, David; Garcia Martin, Hector

    2018-01-01

    Accelerating the Design-Build-Test-Learn (DBTL) cycle in synthetic biology is critical to achieving rapid and facile bioengineering of organisms for the production of, e.g., biofuels and other chemicals. The Learn phase involves using data obtained from the Test phase to inform the next Design phase. As part of the Learn phase, mathematical models of metabolic fluxes give a mechanistic level of comprehension to cellular metabolism, isolating the principle drivers of metabolic behavior from the peripheral ones, and directing future experimental designs and engineering methodologies. Furthermore, the measurement of intracellular metabolic fluxes is specifically noteworthy as providing a rapid and easy-to-understand picture of how carbon and energy flow throughout the cell. Here, we present a detailed guide to performing metabolic flux analysis in the Learn phase of the DBTL cycle, where we show how one can take the isotope labeling data from a 13 C labeling experiment and immediately turn it into a determination of cellular fluxes that points in the direction of genetic engineering strategies that will advance the metabolic engineering process.For our modeling purposes we use the Joint BioEnergy Institute (JBEI) Quantitative Metabolic Modeling (jQMM) library, which provides an open-source, python-based framework for modeling internal metabolic fluxes and making actionable predictions on how to modify cellular metabolism for specific bioengineering goals. It presents a complete toolbox for performing different types of flux analysis such as Flux Balance Analysis, 13 C Metabolic Flux Analysis, and it introduces the capability to use 13 C labeling experimental data to constrain comprehensive genome-scale models through a technique called two-scale 13 C Metabolic Flux Analysis (2S- 13 C MFA) [1]. In addition to several other capabilities, the jQMM is also able to predict the effects of knockouts using the MoMA and ROOM methodologies. The use of the jQMM library is

  3. 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

  4. 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

  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. Succession after fire: variation in \\delta13C of organic tissues and respired CO2 in boreal forests

    Science.gov (United States)

    Fessenden, J. E.; Li, H.; Mack, M.; Schuur, T.; Warren, S.; Randerson, J. T.

    2001-12-01

    Isotope ratios of carbon dioxide and leaf organic matter were measured in 5 neighboring forests of varying ages: 7, 14, 45, 140, and 160 years. These forests are composed primarily of black spruce (Picea Mariana) and quaking aspen (Populus tremuloides) with a shift in species dominance from aspen to spruce 50 years after fire disturbance. Research on the carbon isotope ratios of leaf material and CO2 was conducted to look for influences from species composition, forest age, and time after most recent burn. Samples of organic \\delta13C in whole leaf tissue were collected from the dominant species of each forest. Concurrent aboveground NPP measurements allowed us to estimate total ecosystem \\delta13C by providing a method for weighting \\delta13C of individual species and plant tissues. \\delta13CO2 and [CO2] were measured on canopy CO2 to determine the isotopic ratio of ecosystem respiration. The atmospheric results indicated that the \\delta13C of ecosystem respiration changes with successional stage. Specifically, the aspen dominating forests showed 13C depleted values relative to the spruce dominated forests. Organic results showed more 13C-enriched values with increased forest age and vegetation functional type. Specifically, oldest trees within the coniferous species had the most 13C-enriched values in leaf tissues. These results suggest that increases in the disturbance regime of northern boreal forests will lead to a decrease in the \\delta13C of ecosystem carbon with consequences for the atmospheric \\delta13C budget.

  7. Constraining genome-scale models to represent the bow tie structure of metabolism for 13C metabolic flux analysis

    DEFF Research Database (Denmark)

    Backman, Tyler W.H.; Ando, David; Singh, Jahnavi

    2018-01-01

    for a minimum of fluxes into core metabolism to satisfy these experimental constraints. Together, these methods accelerate and automate the identification of a biologically reasonable set of core reactions for use with 13C MFA or 2S- 13C MFA, as well as provide for a substantially lower set of flux bounds......Determination of internal metabolic fluxes is crucial for fundamental and applied biology because they map how carbon and electrons flow through metabolism to enable cell function. 13C Metabolic Flux Analysis (13C MFA) and Two-Scale 13C Metabolic Flux Analysis (2S-13C MFA) are two techniques used...

  8. Interpretation of non-invasive breath tests using 13C-labeled substrates - a preliminary report with 13C-methacetin

    Directory of Open Access Journals (Sweden)

    Lock JF

    2009-12-01

    Full Text Available Abstract Non-invasive breath tests can serve as valuable diagnostic tools in medicine as they can determine particular enzymatic and metabolic functions in vivo. However, methodological pitfalls have limited the actual clinical application of those tests till today. A major challenge of non-invasive breath tests has remained the provision of individually reliable test results. To overcome these limitations, a better understanding of breath kinetics during non-invasive breaths tests is essential. This analysis compares the breath recovery of a 13C-methacetin breath test with the actual serum kinetics of the substrate. It is shown, that breath and serum kinetics of the same test are significantly different over a period of 60 minutes. The recovery of the tracer 13CO2 in breath seems to be significantly delayed due to intermediate storage in the bicarbonate pool. This has to be taken into account for the application of non-invasive breath test protocols. Otherwise, breath tests might display bicarbonate kinetics despite the metabolic capacity of the particular target enzyme.

  9. 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.

  10. 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.

  11. Examining the utility of bulk otolith δ13C to describe diet in wild-caught black rockfish Sebastes melanops

    Science.gov (United States)

    von Biela, Vanessa; Newsome, Seth D.; Zimmerman, Christian E.

    2015-01-01

    Otolith carbon isotope δ13C values may provide temporally resolved diet proxies in fish. If otolith δ13C values reflect diet, isotope values from recent otolith and muscle tissue should correlate and known ontogenetic diet shifts should be reflected in comparisons between otolith material deposited during different life history stages. We analyzed paired otolith and muscle samples for δ13C from black rockfish Sebastes melanops to examine the potential of otoliths to reflect diet in small (200-299 mm fork length) and large (≥300 mm) fish. We found a significant positive regression between δ13C values from recent (~12 mo) otolith material and muscle in large fish, but not in small fish. Within individual otoliths, δ13C values were enriched by ~3‰ in recent otolith edge material compared to age-0 otolith core material and were consistent with known nearshore-offshore gradients in δ13C values at the base of the food web. Bulk otolith δ13C appeared to provide a broad indicator of dietary carbon sources, but variation in metabolism and dissolved inorganic carbon δ13C among and within individuals likely influences otolith δ13C as well and limits precision. Nevertheless, the results are promising and bulk otolith δ13C may be an appropriate tool to examine large trophic and ecosystem level shifts that have occurred concurrently with changes in habitat, commercial fishing, invasive species, climate change, and other direct or indirect human impacts using historic or ancient otoliths. Future studies should continue to consider the utility of bulk otolith δ13C to describe diet in other marine fish using this simple approach.

  12. 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.

  13. Spatial patterns of leaf δ13C and its relationship with plant functional groups and environmental factors in China

    Science.gov (United States)

    Li, Mingxu; Peng, Changhui; Wang, Meng; Yang, Yanzheng; Zhang, Kerou; Li, Peng; Yang, Yan; Ni, Jian; Zhu, Qiuan

    2017-07-01

    The leaf carbon isotope ratio (δ13C) is a useful parameter for predicting a plant's water use efficiency, as an indicator for plant classification, and even in the reconstruction of paleoclimatic environments. In this study, we investigated the spatial pattern of leaf δ13C values and its relationship with plant functional groups and environmental factors throughout China. The high leaf δ13C in the database appeared in central and western China, and the averaged leaf δ13C was -27.15‰, with a range from -21.05‰ to -31.5‰. The order of the averaged δ13C for plant life forms from most positive to most negative was subshrubs > herbs = shrubs > trees > subtrees. Leaf δ13C is also influenced by some environmental factors, such as mean annual precipitation, relative humidity, mean annual temperature, solar hours, and altitude, although the overall influences are still relatively weak, in particular the influence of MAT and altitude. And we further found that plant functional types are dominant factors that regulate the magnitude of leaf δ13C for an individual site, whereas environmental conditions are key to understanding spatial patterns of leaf δ13C when we consider China as a whole. Ultimately, we conducted a multiple regression model of leaf δ13C with environmental factors and mapped the spatial distribution of leaf δ13C in China by using this model. However, this partial least squares model overestimated leaf δ13C for most life forms, especially for deciduous trees, evergreen shrubs, and subtrees, and thus need more improvement in the future.

  14. 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

  15. Aspects regarding at 13C isotope separation column control using Petri nets system

    International Nuclear Information System (INIS)

    Boca, M L; Ciortea, M E

    2015-01-01

    This paper is intended to show that Petri nets can be also applicable in the chemical industry. It used linear programming, modeling underlying Petri nets, especially discrete event systems for isotopic separation, the purpose of considering and control events in real-time through graphical representations. In this paper it is simulate the control of 13 C Isotope Separation column using Petri nets. The major problem with 13 C comes from the difficulty of obtaining it and raising its natural fraction. Carbon isotopes can be obtained using many methods, one of them being the cryogenic distillation of carbon monoxide. Some few aspects regarding operating conditions and the construction of such cryogenic plants are known today, and even less information are available as far as the separation process modeling and control are concerned. In fact, the efficient control of the carbon monoxide distillation process represents a necessity for large-scale 13 C production. Referring to a classic distillation process, some models for carbon isotope separation have been proposed, some based on mass, component and energy balance equations, some on the nonlinear wave theory or the Cohen equations. For modeling the system it was used Petri nets because in this case it is deal with discrete event systems. In use of the non-timed and with auxiliary times Petri model, the transport stream was divided into sections and these sections will be analyzed successively. Because of the complexity of the system and the large amount of calculations required it was not possible to analyze the system as a unitary whole. A first attempt to model the system as a unitary whole led to the blocking of the model during simulation, because of the large processing times. (paper)

  16. Acetate and bicarbonate assimilation and metabolite formation in Chlamydomonas reinhardtii: a 13C-NMR study.

    Directory of Open Access Journals (Sweden)

    Himanshu Singh

    Full Text Available Cellular metabolite analyses by (13C-NMR showed that C. reinhardtii cells assimilate acetate at a faster rate in heterotrophy than in mixotrophy. While heterotrophic cells produced bicarbonate and CO2aq, mixotrophy cells produced bicarbonate alone as predominant metabolite. Experiments with singly (13C-labelled acetate ((13CH(3-COOH or CH(3-(13COOH supported that both the (13C nuclei give rise to bicarbonate and CO2(aq. The observed metabolite(s upon further incubation led to the production of starch and triacylglycerol (TAG in mixotrophy, whereas in heterotrophy the TAG production was minimal with substantial accumulation of glycerol and starch. Prolonged incubation up to eight days, without the addition of fresh acetate, led to an increased TAG production at the expense of bicarbonate, akin to that of nitrogen-starvation. However, such TAG production was substantially high in mixotrophy as compared to that in heterotrophy. Addition of mitochondrial un-coupler blocked the formation of bicarbonate and CO2(aq in heterotrophic cells, even though acetate uptake ensued. Addition of PSII-inhibitor to mixotrophic cells resulted in partial conversion of bicarbonate into CO2(aq, which were found to be in equilibrium. In an independent experiment, we have monitored assimilation of bicarbonate via photoautotrophy and found that the cells indeed produce starch and TAG at a much faster rate as compared to that in mixotrophy and heterotrophy. Further, we noticed that the accumulation of starch is relatively more as compared to TAG. Based on these observations, we suggest that acetate assimilation in C. reinhardtii does not directly lead to TAG formation but via bicarbonate/CO2(aq pathways. Photoautotrophic mode is found to be the best growth condition for the production of starch and TAG and starch in C. reinhardtii.

  17. Galactose oxidation using {sup 13}C in healthy and galactosemic children

    Energy Technology Data Exchange (ETDEWEB)

    Resende-Campanholi, D.R. [Departamento de Puericultura e Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Porta, G. [Unidade de Hepatologia Pediátrica, Instituto da Criança Prof. Pedro de Alcântara, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Ferrioli, E.; Pfrimer, K. [Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Ciampo, L.A. Del; Junior, J.S. Camelo [Departamento de Puericultura e Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

    2015-01-20

    Galactosemia is an inborn error of galactose metabolism that occurs mainly as the outcome of galactose-1-phosphate uridyltransferase (GALT) deficiency. The ability to assess galactose oxidation following administration of a galactose-labeled isotope (1-{sup 13}C-galactose) allows the determination of galactose metabolism in a practical manner. We aimed to assess the level of galactose oxidation in both healthy and galactosemic Brazilian children. Twenty-one healthy children and seven children with galactosemia ranging from 1 to 7 years of age were studied. A breath test was used to quantitate {sup 13}CO{sub 2} enrichment in exhaled air before and at 30, 60, and 120 min after the oral administration of 7 mg/kg of an aqueous solution of 1-{sup 13}C-galactose to all children. The molar ratios of {sup 13}CO{sub 2} and {sup 12}CO{sub 2} were quantified by the mass/charge ratio (m/z) of stable isotopes in each air sample by gas-isotope-ratio mass spectrometry. In sick children, the cumulative percentage of {sup 13}C from labeled galactose (CUMPCD) in the exhaled air ranged from 0.03% at 30 min to 1.67% at 120 min. In contrast, healthy subjects showed a much broader range in CUMPCD, with values from 0.4% at 30 min to 5.58% at 120 min. The study found a significant difference in galactose oxidation between children with and without galactosemia, demonstrating that the breath test is useful in discriminating children with GALT deficiencies.

  18. 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

  19. 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)

  20. Prediction of chemotherapeutic response of colorectal liver metastases with dynamic gadolinium-DTPA-enhanced MRI and localized 19F MRS pharmacokinetic studies of 5-fluorouracil.

    Science.gov (United States)

    van Laarhoven, H W M; Klomp, D W J; Rijpkema, M; Kamm, Y L M; Wagener, D J Th; Barentsz, J O; Punt, C J A; Heerschap, A

    2007-04-01

    Systemic chemotherapy is effective in only a subset of patients with metastasized colorectal cancer. Therefore, early selection of patients who are most likely to benefit from chemotherapy is desirable. Response to treatment may be determined by the delivery of the drug to the tumor, retention of the drug in the tumor and by the amount of intracellular uptake, metabolic activation and catabolism, as well as other factors. The first aim of this study was to investigate the predictive value of DCE-MRI with the contrast agent Gd-DTPA for tumor response to first-line chemotherapy in patients with liver metastases of colorectal cancer. The second aim was to investigate the predictive value of 5-fluorouracil (FU) uptake, retention and catabolism as measured by localized (19)F MRS for tumor response to FU therapy. Since FU uptake, retention and metabolism may depend on tumor vascularization, the relationship between (19)F MRS and the DCE-MRI parameters k(ep), K(trans) and v(e) was also examined (1). In this study, 37 patients were included. The kinetic parameters of DCE-MRI, k(ep), K(trans) and v(e), before start of treatment did not predict tumor response after 2 months, suggesting that the delivery of chemotherapy by tumor vasculature is not a major factor determining response in first-line treatment. No evident correlations between (19)F MRS parameters and tumor response were found. This suggests that in liver metastases that are not selected on the basis of their tumor diameter, FU uptake and catabolism are not limiting factors for response. The transfer constant K(trans), as measured by DCE-MRI before start of treatment, was negatively correlated with FU half-life in the liver metastases, which suggests that, in metastases with a larger tumor blood flow or permeability surface area product, FU is rapidly washed out from the tumor. c 2006 John Wiley & Sons, Ltd.

  1. Evidence for radiation induced crosslinking in polytetrafluoroethylene by means of high-resolution solid-state 19F high-speed MAS NMR

    International Nuclear Information System (INIS)

    Katoh, Etsuko; Sugisawa, Hisashi; Oshima, Akihiro; Tabata, Yoneho; Seguchi, Tadao; Yamazaki, Toshimasa

    1999-01-01

    Radiation effects on molecular structure of polytetrafluoroethylene (PTFE) were studied by high-resolution solid-state 19 F high speed magic angle spinning (HS MAS) NMR spectroscopy. Samples used for the NMR studies were prepared by electron beam irradiation of PTFE with a wide range of irradiation doses from 0.5-10 MGy in the molten state at 340 deg. C under oxygen-free atmosphere. While the non-irradiated PTFE displayed only an intense peak of the internal CF 2 , several new signals corresponding to CF 3 , CF 2 and CF groups were observed for the PTFE which was high temperature irradiated at 340 deg. C in oxygen-free atmosphere (hti-PTFE). Intensities of these new signals increased with an increase of irradiation dose. The present solid-state 19 F HS MAS NMR studies provide not only the first experimental evidence regarding the existence of crosslinking structure in hti-PTFE, directly detected as the CF signal, but also the crosslinking density which can be estimated from a proportion of the CF versus total fluorine signal intensities. The higher the irradiation dose, the higher the crosslinking density; hti-PTFE with 10 MGy contains one crosslinking site per approximately 24 CF 2 groups, while the hti-PTFE with 5 MGy contains one crosslinking site per approximately 36 CF 2 groups. Further, G value of crosslinking (G(x)) was estimated from the signal intensities of 19 F HS MAS NMR spectra. The highest G(x)-value, 1.85, was observed for the 2MGy hti-PTFE sample, suggesting that crosslinking of PTFE is formed most efficaciously with 2 MGy irradiation in the molten state at 340 deg. C under oxygen-free atmosphere

  2. Conformational Plasticity of the Cell-Penetrating Peptide SAP As Revealed by Solid-State 19F-NMR and Circular Dichroism Spectroscopies.

    Science.gov (United States)

    Afonin, Sergii; Kubyshkin, Vladimir; Mykhailiuk, Pavel K; Komarov, Igor V; Ulrich, Anne S

    2017-07-13

    The cell-penetrating peptide SAP, which was designed as an amphipathic poly-l-proline helix II (PPII), was suggested to self-assemble into regular fibrils that are relevant for its internalization. Herein we have analyzed the structure of SAP in the membrane-bound state by solid-state 19 F-NMR, which revealed other structural states, in addition to the expected surface-aligned PPII. Trifluoromethyl-bicyclopentyl-glycine (CF 3 -Bpg) and two rigid isomers of trifluoromethyl-4,5-methanoprolines (CF 3 -MePro) were used as labels for 19 F-NMR analysis. The equilibria between different conformations of SAP were studied and were found to be shifted by the substituents at Pro-11. Synchrotron-CD results suggested that substituting Pro-11 by CF 3 -MePro governed the coil-to-PPII equilibrium in solution and in the presence of a lipid bilayer. Using CD and 19 F-NMR, we examined the slow kinetics of the association of SAP with membranes and the dependence of the SAP conformational dynamics on the lipid composition. The peptide did not bind to lipids in the solid ordered phase and aggregated only in the liquid ordered "raft"-like bilayers. Self-association could not be detected in solution or in the presence of liquid disordered membranes. Surface-bound amphipathic SAP in a nonaggregated state was structured as a mixture of nonideal extended conformations reflecting the equilibrium already present in solution, i.e., before binding to the membrane.

  3. 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

  4. The use of isotope ratios (13C/12C) for vegetable oils authentication

    Science.gov (United States)

    Cristea, G.; Magdas, D. A.; Mirel, V.

    2012-02-01

    Stable isotopes are now increasingly used for the control of the geographical origin or authenticity of food products. The falsification may be more or less sophisticated and its sophistication as well as its costs increases with the improvement of analytical methods. In this study 22 vegetable oils (olive, sunflower, palm, maize) commercialized on Romanian market were investigated by mean of δ13C in bulk oil and the obtained results were compared with those reported in literature in order to check the labeling of these natural products. The obtained results were in the range of the mean values found in the literature for these types of oils, thus providing their accurate labeling.

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

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.; Wahidullah, S.

    quino- nes or semiquinones which exhibit 13C resonance at around 195 ppm. Free radicals of semiquinone type have been reported from the aquatic environment [2]. Spectra of all the four samples show absorption at 195 ppm. The total acidity of marine..., significant resonance at 55 ppm (8.9) from aromatic methoxy carbon suggests that phenol is present mostly as methyl ether and not as free phenol. The signal at 55 ppm is also attributed to aliphatic carbon adjacent to the amino functional group as in amino...

  6. Regioselectivity of tributyltin ether mediated alkylations. A 119Sn and 13C NMR study

    International Nuclear Information System (INIS)

    Cruzado, C.; Bernabe, M.; Martin-Lomas, M.

    1989-01-01

    The 119 Sn and 13 C NMR spectra of the stannylated species resulting from the treatment of conformationally rigid polyhydroxylated compounds with bis(tributyltin) oxide have been determined and the effect of N-methylimidazole, added as catalyst in tributyltin ether mediated regioselective alkylations, has been investigated. The observed signal intensity changes, upfield shifts, signal broadenings, and the results of variable temperature experiments have been interpreted as indicative of the selective formation of pentacoordinated tin species, involving conveniently disposed adjacent hydroxyl groups, on addition of the catalyst. On these bases, a mechanistic hypothesis for the observed regioselectivity of N-methylimidazole-catalyzed tributyltin ether mediated benzylations is proposed. 13 references, 5 tables

  7. Conformational analysis of 9,10-dihydroanthracenes. Molecular mechanics calculations and /sup 13/C NMR

    Energy Technology Data Exchange (ETDEWEB)

    Rabideau, P.W.; Mooney, J.L.; Lipkowitz, K.B.

    1986-12-24

    The conformational analyses of 9, 10-dihydroanthracene and several of its methylated and ethylated derivatives are studied by empirical force field calculations (MM2 and MMPI). The computational results are considered in light of previous and current carbon NMR data. Model compounds are examined which involve fixed, planar, and boat-shaped conformations about the central ring, and these /sup 13/C NMR data are then compared with flexible systems. It is concluded that carbon chemical shifts and carbon-hydrogen coupling constants are consistent with the results of molecular mechanics calculations which indicate a greater tendency for planarity around the central ring than previously considered.

  8. Protolytic properties of polyamine wasp toxin analogues studied by 13C NMR spectroscopy

    DEFF Research Database (Denmark)

    Strømgaard, Kristian; Piazzi, Lorna; Olsen, Christian A

    2006-01-01

    Acid-base properties of the natural polyamine wasp toxin PhTX-433 (1) and seven synthetic analogues [PhTX-343 (2), PhTX-334 (3), PhTX-443 (4), PhTX-434 (5), PhTX-344 (6), PhTX-444 (7), and PhTX-333 (8)], each having four protolytic sites, were characterized by 13C NMR spectroscopy. Nonlinear......, multiparameter, simultaneous fit of all chemical shift data obtained from the NMR titration curves yielded macroscopic pKa values as well as intrinsic chemical shift data of all differently protonated macrospecies. Analyses of the chemical shift data demonstrated strong interactions between all four sites...

  9. Crystal structures of Er4Ni13C4 and UW4C4

    International Nuclear Information System (INIS)

    Khalili, M.M.; Bodak, O.I.; Marusin, E.P.; Pecharskaya, A.O.

    1990-01-01

    Crystal structures of Er 4 Ni 13 C 4 (1) (sp.gr. Cmmm, a=1.1975(4), b=1.1694(3), c=0.3856(1) nm, Z=2) and UW 4 C 4 (2) (sp.gr. P4/m, a=0.8328(8), c=0.31345(9) nm, Z=2), relating to new types are determined. Structural type (1) is a derivative of La 2 Ni 5 C 3 structure, structural type (2) is close to UCr 4 C 4 structure

  10. 13C NMR investigation of the structure of cationic carbonyls in transition metal zeolites

    International Nuclear Information System (INIS)

    Ben Taarit, Y.

    1979-01-01

    13 C NMR spectroscopy was used to investigate the nature of carbon monoxide adsorbed on transition metal ions hosted in a synthetic faujastite type zeolite. The adsorbed CO species was characterised by a highly shielded carbon nucleus. Using the Pople approximation for the paramagnetic shielding term, the observed chemical shift was rationalised assuming the formation of a cationic carbonyl species with an appreciable electronic transfer from the carbon lone pair to the transition metal ion and negligible π back-bonding if at all. (Auth.)

  11. Occurrence, biological activities and 13C NMR data of amides from Piper (Piperaceae

    Directory of Open Access Journals (Sweden)

    Jeferson C. do Nascimento

    2012-01-01

    Full Text Available This manuscript describes an update review with up to 285 references concerning the occurrence of amides from a variety of species of the genus Piper (Piperaceae. Besides addressing occurrence, this review also describes the biological activities attributed to extracts and pure compounds, a compiled 13C NMR data set, the main correlations between structural and NMR spectroscopic data of these compounds, and employment of hyphened techniques such as LC-MS, GC-MS and NMR for analysis of amides from biological samples and crude Piper extracts.

  12. Occurrence, biological activities and 13C NMR data of amides from Piper (Piperaceae)

    International Nuclear Information System (INIS)

    Nascimento, Jeferson C. do; Paula, Vanderlucia F. de; David, Jorge M.; David, Juceni P.

    2012-01-01

    This manuscript describes an update review with up to 285 references concerning the occurrence of amides from a variety of species of the genus Piper (Piperaceae). Besides addressing occurrence, this review also describes the biological activities attributed to extracts and pure compounds, a compiled 13 C NMR data set, the main correlations between structural and NMR spectroscopic data of these compounds, and employment of hyphened techniques such as LC-MS, GC-MS and NMR for analysis of amides from biological samples and crude Piper extracts. (author)

  13. Occurrence, biological activities and {sup 13}C NMR data of amides from Piper (Piperaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Jeferson C. do; Paula, Vanderlucia F. de [Universidade Estadual do Sudoeste da Bahia, Jequie, BA (Brazil). Dept. de Quimica e Exatas; David, Jorge M. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica; David, Juceni P., E-mail: jmdavid@ufba.br [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Fac. de Farmacia

    2012-07-01

    This manuscript describes an update review with up to 285 references concerning the occurrence of amides from a variety of species of the genus Piper (Piperaceae). Besides addressing occurrence, this review also describes the biological activities attributed to extracts and pure compounds, a compiled {sup 13}C NMR data set, the main correlations between structural and NMR spectroscopic data of these compounds, and employment of hyphened techniques such as LC-MS, GC-MS and NMR for analysis of amides from biological samples and crude Piper extracts. (author)

  14. The Hirnantian δ13C Positive Excursion in the Nabiullino Section (South Urals)

    Science.gov (United States)

    Yakupov, R. R.; Mavrinskaya, T. M.; Smoleva, I. V.

    2018-02-01

    The upper Sandbian, Katian, and Hirnantian complexes of conodonts in the upper Ordovician section of the western slope of the Southern Urals near the village of Nabiullino were studied. The δ13C positive excursion with a maximum of 3.3‰ associated with the global Hirnantian isotopic event, HICE, was fixed for the first time. This excursion shows the beginning of the Hirnantian stage in the terrigenous-carbonate section of the upper Ordovician in the Southern Urals. It coincides with the first occurrence of the Hirnantian conodont species of Gamachignathus ensifer and the conodonts of shallow-water biophacies, Aphelognathus-Ozarkodina, reflecting the global glacio-eustatic event.

  15. 1H and 13C NMR spectral data of new saponins from Cordia piauhiensis.

    Science.gov (United States)

    Santos, Renata P; Silveira, Edilberto R; Uchôa, Daniel Esdras de A; Pessoa, Otília Deusdênia L; Viana, Francisco Arnaldo; Braz-Filho, Raimundo

    2007-08-01

    Two new bidesmoside triterpenoid saponins were isolated from stems of Cordia piauhiensis. Their structures, characterized as 3-O-alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl pomolic acid 28-O-beta-D-glucopyranosyl ester (1) and 3-O-alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranosyl ester (2), were unequivocally established after extensive NMR (1H, 13C, DEPT 135 degrees, COSY, HSQC, HMBC, TOCSY, and NOESY) studies. Copyright 2007 John Wiley & Sons, Ltd.

  16. NMR shielding and spin–rotation constants of {sup 175}LuX (X = {sup 19}F, {sup 35}Cl, {sup 79}Br, {sup 127}I) molecules

    Energy Technology Data Exchange (ETDEWEB)

    Demissie, Taye B. [Centre for Theoretical and Computational Chemistry Department of Chemistry, UiT – The Arctic University of Norway, N-9037 Tromsø (Norway)

    2015-12-31

    This presentation demonstrates the relativistic effects on the spin-rotation constants, absolute nuclear magnetic resonance (NMR) shielding constants and shielding spans of {sup 175}LuX (X = {sup 19}F, {sup 35}Cl, {sup 79}Br, {sup 127}I) molecules. The results are obtained from calculations performed using density functional theory (non-relativistic and four-component relativistic) and coupled-cluster calculations. The spin-rotation constants are compared with available experimental values. In most of the molecules studied, relativistic effects make an order of magnitude difference on the NMR absolute shielding constants.

  17. 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...

  18. A simple mixing explanation for late Pleistocene changes in the Pacific-South Atlantic benthic δ13C gradient

    Directory of Open Access Journals (Sweden)

    L. E. Lisiecki

    2010-05-01

    Full Text Available The fact that the deep-ocean benthic δ13C minimum shifted from the North Pacific to the South Atlantic during the Last Glacial Maximum is often interpretted as evidence of a change in deep water circulation, such as the development of deep water ventilation in the North Pacific or a decrease in Southern Ocean overturning. This study re-evaluates the implications of changes in benthic δ13C gradients by comparing Pacific Deep Water (PDW δ13C measurements with the values expected for the null hypothesis that PDW ventilation sources remained unchanged throughout the Late Pleistocene. The δ13C compositions of PDW, Northern Component Water (NCW and Southern Component Water (SCW are estimated from regional benthic δ13C stacks of 3–6 sites. Changes in PDW δ13C and PDW-SCW δ13C gradients over the past 800 kyr are found to be well described by a constant mixture of 60% NCW and 40% SCW plus a constant Pacific remineralization offset of −0.5‰. Thus, a change in PDW ventilation cannot be inferred solely on the basis of changes in the Pacific-South Atlantic benthic δ13C gradient.

  19. Validation of dentine deposition rates in beluga whales by interspecies cross dating of temporal δ13C trends in teeth

    Directory of Open Access Journals (Sweden)

    Cory JD Matthews

    2014-11-01

    Full Text Available Isotopic time series from sequentially sampled growth layer groups (GLGs in marine mammal teeth can be combined to build chronologies allowing assessment of isotopic variation in marine ecosystems. Synchronous recording of baseline isotopic variation across dentinal GLGs of species with temporal and spatial overlap in foraging offers a unique opportunity for validation of marine mammal age estimation procedures through calibration of GLG deposition rates in one species against another whose GLG deposition has been independently determined. In this study, we compare trends in stable carbon isotope ratios (d13C across dentinal GLGs of three eastern Canadian Arctic (ECA beluga (Delphinapterus leucas populations through the 1960s-2000s with a d13C time series measured across dentinal GLGs of ECA/Northwest Atlantic killer whales (Orcinus orca from 1944-1999. We use confirmed annual GLG deposition in killer whales as a means to assess beluga GLG deposition, and show linear d13C declines across chronologies of both species were statistically indistinguishable when based on annual GLG deposition in beluga whales, but differed when based on biannual deposition. We suggest d13C declines reflect the oceanic 13C Suess effect, and provide additional support for annual GLG deposition in beluga whales by comparing rates of d13C declines across beluga GLGs with published annual d13C declines attributed to the oceanic 13C Suess effect in the North Atlantic.

  20. Evolution of E. coli on [U-13C] Glucose Reveals a Negligible Isotopic Influence on Metabolism and Physiology

    DEFF Research Database (Denmark)

    Sandberg, Troy E.; Long, Christopher P.; Gonzalez, Jacqueline E.

    2016-01-01

    13C-Metabolic flux analysis (13C-MFA) traditionally assumes that kinetic isotope effects from isotopically labeled compounds do not appreciably alter cellular growth or metabolism, despite indications that some biochemical reactions can be non-negligibly impacted. Here, populations of Escherichia...

  1. A First Laboratory Utilizing NMR for Undergraduate Education: Characterization of Edible Fats and Oils by Quantitative [superscript 13]C NMR

    Science.gov (United States)

    Fry, Charles G.; Hofstetter, Heike; Bowman, Matthew D.

    2017-01-01

    Quantitative [superscript 13]C NMR provides a straightforward method of analyzing edible oils in undergraduate chemistry laboratories. [superscript 13]C spectra are relatively easy to understand, and are much simpler to analyze and workup than corresponding [superscript 1]H spectra. Average chain length, degree of saturation, and average…

  2. Modeling non-linear kinetics of hyperpolarized [1-(13)C] pyruvate in the crystalloid-perfused rat heart

    NARCIS (Netherlands)

    Mariotti, E.; Orton, M. R.; Eerbeek, O.; Ashruf, J. F.; Zuurbier, C. J.; Southworth, R.; Eykyn, T. R.

    2016-01-01

    Hyperpolarized (13)C MR measurements have the potential to display non-linear kinetics. We have developed an approach to describe possible non-first-order kinetics of hyperpolarized [1-(13)C] pyruvate employing a system of differential equations that agrees with the principle of conservation of mass

  3. 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

  4. Synthesis of 13C-labeled vitamin E and interaction between vitamin E and phospholipid in liposome

    International Nuclear Information System (INIS)

    urano, S.; Matsuo, M.

    1986-01-01

    Vitamin E with a 13 C-labeled isoprenoid side chain, [4'a- 13 C], [6'- 13 C], [8'a- 13 C] and [12'a and 13'- 13 C]α-tocopherols were synthesized. These compounds were incorporated into three kinds of lecithin liposomes from dipalmitoyl phosphatidyl cholin, egg lecithin and rat liver lecithin, of which arachidonic acid contents are 0, 2.6 and 19.0%, respectively. T 1 values, which were measured by NMR for the labeled carbons, indicate that the segmental motion tends to increase with the increase of the distance from the chroman ring. This tendency is not affected with the arachidonic acid contents of phospholipids. This result can not be explained by Lucy's hypothesis. 1 figure; 1 table

  5. Trends of 13C/12C ratios in pinyon tree rings of the American Southwest and the global carbon cycle

    International Nuclear Information System (INIS)

    Leavitt, S.W.; Long, A.

    1986-01-01

    An accurate atmospheric 13 C/ 12 C chronology can provide important constraints to models of the global carbon cycle. Trees accumulate carbon from atmospheric CO 2 into growth rings and offer potential for 13 C/ 12 C reconstructions, but results have not been reproducible. This paper presents δ 13 C curves from 5 sites, representing 20 pinyon (Pinus edulis) trees, where cores of 4 trees from each site have been pooled into a composite sample. Isotopic analysis of cellulose in 5-yr ring groups produces curves with a general trend of decreasing δ 13 C after 1800, but with pronounced short-term fluctuations superimposed upon the trend. Evidence indicates the fluctuations are strongly related to moisture availability (drought). A mean curve of the 5 δ 13 C chronologies from which the fossil-fuel component is subtracted suggests a substantial biospheric CO 2 contribution to the atmosphere since 1800

  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. Plasma incorporation, apparent retroconversion and β-oxidation of 13C-docosahexaenoic acid in the elderly

    Directory of Open Access Journals (Sweden)

    Brenna J Thomas

    2011-01-01

    Full Text Available Abstract Background Higher fish or higher docosahexaenoic acid (DHA intake normally correlates positively with higher plasma DHA level, but recent evidence suggests that the positive relationship between intake and plasma levels of DHA is less clear in the elderly. Methods We compared the metabolism of 13C-DHA in six healthy elderly (mean - 77 y old and six young adults (mean - 27 y old. All participants were given a single oral dose of 50 mg of uniformly labelled 13C-DHA. Tracer incorporation into fatty acids of plasma triglycerides, free fatty acids, cholesteryl esters and phospholipids, as well as apparent retroconversion and β-oxidation of 13C-DHA were evaluated 4 h, 24 h, 7d and 28d later. Results Plasma incorporation and β-oxidation of 13C-DHA reached a maximum within 4 h in both groups, but 13C-DHA was transiently higher in all plasma lipids of the elderly 4 h to 28d later. At 4 h post-dose, 13C-DHA β-oxidation was 1.9 times higher in the elderly, but over 7d, cumulative β-oxidation of 13C-DHA was not different in the two groups (35% in the elderly and 38% in the young. Apparent retroconversion of 13C-DHA was well below 10% of 13C-DHA recovered in plasma at all time points, and was 2.1 times higher in the elderly 24 h and 7d after tracer intake. Conclusions We conclude that 13C-DHA metabolism changes significantly during healthy aging. Since DHA is a potentially important molecule in neuro-protection, these changes may be relevant to the higher vulnerability of the elderly to cognitive decline.

  8. 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.

  9. Effect of light and brine shrimp on skeletal δ 13C in the Hawaiian coral Porites compressa: a tank experiment

    Science.gov (United States)

    Grottoli, Andréa G.

    2002-06-01

    Previous experimental fieldwork showed that coral skeletal δ13C values decreased when solar intensity was reduced, and increased in the absence of zooplankton. However, actual seasonal changes in solar irradiance levels are typically less pronounced than those used in the previous experiment and the effect of increases in the consumption of zooplankton in the coral diet on skeletal δ13C remains relatively unknown. In the present study, the effects of four different light and heterotrophy regimes on coral skeletal δ13C values were measured. Porites compressa corals were grown in outdoor flow-through tanks under 112%, 100%, 75%, and 50% light conditions at the Hawaii Institute of Marine Biology, Hawaii. In addition, corals were fed either zero, low, medium, or high concentrations of brine shrimp. Decreases in light from 100% resulted in significant decreases in δ13C that is most likely due to a corresponding decrease in photosynthesis. Increases in light to 112% also resulted in a decrease in δ13C values. This latter response may be a consequence of photoinhibition. The overall curved response in δ13C values was described by a significant quadratic function. Increases in brine shrimp concentrations resulted in increased skeletal δ13C levels. This unexpected outcome appears to be attributable to enhanced nitrogen supply associated with the brine shrimp diet which led to increased zooxanthellae concentrations, increased photosynthesis rates, and thus increased δ13C values. This result highlights the potential influence of nutrients from heterotrophically acquired carbon in maintaining the zooxanthellae-host symbiosis in balance. In addition, evidence is presented that suggests that coral skeletal growth and δ13C are decoupled. These results increase our knowledge of how light and heterotrophy affects the δ13C of coral skeletons.

  10. Affordable uniform isotope labeling with 2H, 13C and 15N in insect cells

    International Nuclear Information System (INIS)

    Sitarska, Agnieszka; Skora, Lukasz; Klopp, Julia; Roest, Susan; Fernández, César; Shrestha, Binesh; Gossert, Alvar D.

    2015-01-01

    For a wide range of proteins of high interest, the major obstacle for NMR studies is the lack of an affordable eukaryotic expression system for isotope labeling. Here, a simple and affordable protocol is presented to produce uniform labeled proteins in the most prevalent eukaryotic expression system for structural biology, namely Spodoptera frugiperda insect cells. Incorporation levels of 80 % can be achieved for 15 N and 13 C with yields comparable to expression in full media. For 2 H, 15 N and 2 H, 13 C, 15 N labeling, incorporation is only slightly lower with 75 and 73 %, respectively, and yields are typically twofold reduced. The media were optimized for isotope incorporation, reproducibility, simplicity and cost. High isotope incorporation levels for all labeling patterns are achieved by using labeled algal amino acid extracts and exploiting well-known biochemical pathways. The final formulation consists of just five commercially available components, at costs 12-fold lower than labeling media from vendors. The approach was applied to several cytosolic and secreted target proteins

  11. The determination of δ13C in atmospheric methane in the Southern Hemisphere

    International Nuclear Information System (INIS)

    Lowe, D.C.; Manning, M.R.

    2002-01-01

    A technique to make measurements of δ 13 C in atmospheric methane (δ 13 CH 4 ) to a precision of 0.02 per mille (1 sigma) is presented. Measurements of the mixing ratio and δ 13 CH 4 from Baring Head, New Zealand and Scott Base, Antarctica are reviewed for the period 1989 to 1998. The data show persistent but irregular seasonal cycles in δ 13 CH 4 ranging from 0.1-0.3 per mille superimposed on an increasing secular trend of about 0.04 per mille.year -1 . In 1990/91 a 0.2 per mille positive anomaly appeared in this trend. The causes of the anomaly remain unresolved but, during 1992 when it disappeared, the decrease in δ 13 C was approximately coincident with a decrease in growth rate consistent with a decrease in biomass burning sources, which are relatively enriched in 13 CH 4 . δ 13 CH 4 data are also reported from large clean air samples collected every 2.5 deg. to 5 deg. of latitude on four voyages across the Pacific between New Zealand and the West Coast of the USA in 1996 and 1997. These data show that the inter-hemispheric gradient for δ 13 CH 4 was highly dependent on season, and varied from less than 0.1 per mille in June 1996 to more than 0.5 per mille in November 1996 with an estimated annual mean of 0.2-0.3 per mille. (author)

  12. High-level 13C-enrichment of random and synchronous populations of Chlamydomonas reinhardii

    International Nuclear Information System (INIS)

    Price, R.L.; Crissman, H.A.; Martin, J.C.; Kollman, V.H.

    1975-01-01

    The alga Chlamydomonas reinhardii was grown in suspension culture at high levels of 13 C-enrichment (98 mol percent) both in synchronous and random populations for the purpose of investigating possible macro- and ultrastructural changes in the cell as induced by essentially total carbon replacement. The algae, grown in spinner flasks, were analyzed using a newly developed multiparameter flow-system technique applied to characterizing various algal genera. The versatility of this technique provides for measuring and processing several cell characteristics simultaneously and separating cells according to selected combinations of parameters. In these studies, cell volume (by Coulter aperture) and DNA and chlorophyll content were determined simultaneously. Cell ultrastructure was examined at various levels of isotope enrichment and time periods by electron microscopy. The data presented for synchronous growth of this organism demonstrate the absence of biological effects (considering the parameters measured) due to the almost total replacement of cellular 12 C with 13 C. Interpretational problems encountered when looking for biological effects on random populations are discussed

  13. Metabolism and transport studies of exogenous compounds thanks to 13C uniform isotopic enrichment

    International Nuclear Information System (INIS)

    Bravin, F.

    2008-12-01

    The study of many exogenous compounds does not raise difficulties when they are isolated, purified and in quantities sufficient for the usual detection methods used in biology (Chromatography, NMR, Mass Spectrometry, etc). When they are found in a biological fluid (blood, urines,..), they are often in infinitesimal amount such as the effect of their biological matrices or the background noise that make their detection and their quantification very delicate. The use of internal standards uniformly enriched with carbon 13 and/or nitrogen 15 makes it possible to obtain a signal more easily recognizable and identifiable thanks to the presence of the isotopes (peaks shifted in a mass spectrum for example). This is why, complementary to the analytical and biochemical studies of zearalenone (ZEN) metabolism, we were interested in building mass spectra of molecules enriched (rates between 0 and 1) by various isotopes ( 13 C, 15 N, 18 O and 2 H). In parallel we studied the influence of the 13 C enrichment on the reactivity of a given molecule, from a theoretical and an experimental point of view. (author)

  14. Natural isotope correction of MS/MS measurements for metabolomics and (13)C fluxomics.

    Science.gov (United States)

    Niedenführ, Sebastian; ten Pierick, Angela; van Dam, Patricia T N; Suarez-Mendez, Camilo A; Nöh, Katharina; Wahl, S Aljoscha

    2016-05-01

    Fluxomics and metabolomics are crucial tools for metabolic engineering and biomedical analysis to determine the in vivo cellular state. Especially, the application of (13)C isotopes allows comprehensive insights into the functional operation of cellular metabolism. Compared to single MS, tandem mass spectrometry (MS/MS) provides more detailed and accurate measurements of the metabolite enrichment patterns (tandem mass isotopomers), increasing the accuracy of metabolite concentration measurements and metabolic flux estimation. MS-type data from isotope labeling experiments is biased by naturally occurring stable isotopes (C, H, N, O, etc.). In particular, GC-MS(/MS) requires derivatization for the usually non-volatile intracellular metabolites introducing additional natural isotopes leading to measurements that do not directly represent the carbon labeling distribution. To make full use of LC- and GC-MS/MS mass isotopomer measurements, the influence of natural isotopes has to be eliminated (corrected). Our correction approach is analyzed for the two most common applications; (13)C fluxomics and isotope dilution mass spectrometry (IDMS) based metabolomics. Natural isotopes can have an impact on the calculated flux distribution which strongly depends on the substrate labeling and the actual flux distribution. Second, we show that in IDMS based metabolomics natural isotopes lead to underestimated concentrations that can and should be corrected with a nonlinear calibration. Our simulations indicate that the correction for natural abundance in isotope based fluxomics and quantitative metabolomics is essential for correct data interpretation. © 2015 Wiley Periodicals, Inc.

  15. Preliminary Study of 13C/12C Application for the Detection of Adulterated Honey

    International Nuclear Information System (INIS)

    Loestanatjaroen, S.

    2014-01-01

    Honey and pollen in natural products derived from the same plant both share the same carbon source; as a result their 13 C isotope signature should be identical. The majority of honey adulteration in Thailand was done particularly by adding cheap sugars such as high sucrose cane syrup (HSCS). The accepted differences in 13 C/ 12 C between honey and its associated protein extract is -1δ/ο deviation, which provides the international benchmark of 7% C4 sugar addition. This study reports the preliminary detection of adulterated Thai honey samples by using isotope ratio mass spectrometer coupled to elemental analyzer (EAIRMS). The 5 Thailand honey samples and the pure honey were adulterated with HSCS dilution as: 0, 0.5, 1, 5, 7, 10, 15 and 50%, respectively. The results were found that two of the Thai honey samples and of 10, 15, and 50% dilution were adulterated. The result of analyzed cane sugar of ten replicates were found -11.2 and -10.8 δdeviation, respectively.

  16. Computational characterization of 13C NMR lineshapes of carbon dioxide in structure 1 clathrate hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Dornan, P.; Woo, T.K. [Ottawa Univ., ON (Canada). Dept. of Chemistry

    2008-07-01

    Nonspherical large cages in structure one clathrates impose non-uniform motion of nonspherical guest molecules and anisotropic lineshapes in nuclear magnetic resonance (NMR) spectra of the guest. This paper presented a general method for calculating the chemical shift lineshape anisotropy of guest molecules in clathrate hydrate compounds from molecular dynamics simulations for the case of weak host, guest dipolar coupling. In order to calculate the cage chemical shielding tensors and the NMR lineshape produced by each guest molecule, the study involved the use of orientational distributions from molecular dynamics simulation along with time and powder angle averaging. The total predicted lineshape anisotropy was calculated from the superposition of the lineshapes of all guests. The approach was applied to calculate the temperature dependent 13C NMR lineshape anisotropy of carbon dioxide in structure 1 clathrates. The paper presented the computational methodology and results and discussion. It was concluded that the resulting lineshapes were in good agreement with the experimental 13C NMR spectrum at each temperature. The method provided a uniform procedure to calculate the lineshapes at different temperatures and no prior assumptions about the nature of the motion of the guest in cages was required. 37 refs., 2 tabs., 3 figs.

  17. Synthesis and biosynthesis of 13C, 15N labeled deoxynucleosides useful for biomolecular structural determinations

    International Nuclear Information System (INIS)

    Ashburn, D.A.; Garcia, K.; Hanners, J.L.; Silks, L.A. III; Unkefer, C.J.

    1994-01-01

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

  18. Comparison of bolus versus fractionated oral applications of [13C]-linoleic acid in humans.

    Science.gov (United States)

    Demmelmair, H; Iser, B; Rauh-Pfeiffer, A; Koletzko, B

    1999-07-01

    The endogenous conversion of linoleic acid into long-chain polyunsaturated fatty acids is of potential importance for meeting substrate requirements, particularly in young infants. After application of [13C]-linoleic acid, we estimated its conversion to dihomo-gamma-linolenic and arachidonic acids from only two blood samples. Oral tracer doses were given to five healthy adults as a single bolus. In four subjects the tracer was given in nine equal portions over 3 days. Concentration and 13C content of fatty acids from serum phospholipids were analysed by gas chromatography combustion isotope ratio-mass spectrometry. Areas under the tracer-concentration curves were calculated, and fractional transfer and turnover rates estimated from compartmental models. The median fractional turnover of linoleic acid was 93.7% per day (interquartile range 25.3) in the bolus group and 80. 0% per day (6.3) in the fraction group (NS). Fractional conversion of linoleic to dihomo-gamma-linolenic acid was 1.5% (0.9) vs. 2.1% (0.7) (bolus vs. fraction, P /= 0.94, P < 0.05) with the ratio of areas under the curve. Using areas under the curve overestimates the conversion, because different residence times are not considered. Estimation of conversion intensity appears possible with only one blood sample obtained after tracer application.

  19. Synthesis and biosynthesis of 13C-, 15N-labeled deoxynucleosides useful for biomolecular structural determinations

    International Nuclear Information System (INIS)

    Ashburn, D.A.; Garcia, K.; Hanners, J.L.; Silks, L.A. III; Unkefer, C.J.

    1994-01-01

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

  20. (13)C-metabolic flux analysis of lipid accumulation in the oleaginous fungus Mucor circinelloides.

    Science.gov (United States)

    Zhao, Lina; Zhang, Huaiyuan; Wang, Liping; Chen, Haiqin; Chen, Yong Q; Chen, Wei; Song, Yuanda

    2015-12-01

    The oleaginous fungus Mucor circinelloides is of industrial interest because it can produce high levels of polyunsaturated fatty acid γ-linolenic acid. M. circinelloides CBS 277.49 is able to accumulate less than 15% of cell dry weight as lipids, while M. circinelloides WJ11 can accumulate lipid up to 36%. In order to better understand the mechanisms behind the differential lipid accumulation in these two strains, tracer experiments with (13)C-glucose were performed with the growth of M. circinelloides and subsequent gas chromatography-mass spectrometric detection of (13)C-patterns in proteinogenic amino acids was carried out to identify the metabolic network topology and estimate intracellular fluxes. Our results showed that the high oleaginous strain WJ11 had higher flux of pentose phosphate pathway and malic enzyme, lower flux in tricarboxylic acid cycle, higher flux in glyoxylate cycle and ATP: citrate lyase, together, it might provide more NADPH and substrate acetyl-CoA for fatty acid synthesis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Neoproterozoic diamictite-cap carbonate succession and δ13C chemostratigraphy from eastern Sonora, Mexico

    Science.gov (United States)

    Corsetti, Frank A.; Stewart, John H.; Hagadorn, James W.

    2007-01-01

    Despite the occurrence of Neoproterozoic strata throughout the southwestern U.S. and Sonora, Mexico, glacial units overlain by enigmatic cap carbonates have not been well-documented south of Death Valley, California. Here, we describe in detail the first glaciogenic diamictite and cap carbonate succession from Mexico, found in the Cerro Las Bolas Group. The diamictite is exposed near Sahuaripa, Sonora, and is overlain by a 5 m thick very finely-laminated dolostone with soft sediment folds. Carbon isotopic chemostratigraphy of the finely-laminated dolostone reveals a negative δ13C anomaly (down to − 3.2‰ PDB) characteristic of cap carbonates worldwide. Carbon isotopic values rise to + 10‰ across ∼ 400 m of section in overlying carbonates of the Mina el Mezquite and Monteso Formations. The pattern recorded here is mostly characteristic of post-Sturtian (ca. ≤ 700 Ma), but pre-Marinoan (ca. ≥ 635 Ma) time. However, the Cerro Las Bolas Group shares ambiguity common to most Neoproterozoic successions: it lacks useful radiometric age constraints and biostratigraphically useful fossils, and its δ13C signature is oscillatory and therefore somewhat equivocal.

  2. δ 13C evidence that high primary productivity delayed recovery from end-Permian mass extinction

    Science.gov (United States)

    Meyer, K. M.; Yu, M.; Jost, A. B.; Kelley, B. M.; Payne, J. L.

    2011-02-01

    Euxinia was widespread during and after the end-Permian mass extinction and is commonly cited as an explanation for delayed biotic recovery during Early Triassic time. This anoxic, sulfidic episode has been ascribed to both low- and high-productivity states in the marine water column, leaving the causes of euxinia and the mechanisms underlying delayed recovery poorly understood. Here we use isotopic analysis to examine the changing chemical structure of the water column through the recovery interval and thereby better constrain paleoproductivity. The δ 13C of limestones from 5 stratigraphic sections in south China displays a negative gradient of approximately 4‰ from shallow-to-deep water facies within the Lower Triassic. This intense gradient declines within Spathian and lowermost Middle Triassic strata, coincident with accelerated biotic recovery and carbon cycle stabilization. Model simulations show that high nutrient levels and a vigorous biological pump are required to sustain such a large gradient in δ 13C, indicating that Early Triassic ocean anoxia and delayed recovery of benthic animal ecosystems resulted from too much productivity rather than too little.

  3. Conformational analysis of capsaicin using 13C, 15N MAS NMR, GIAO DFT and GA calculations

    Science.gov (United States)

    Siudem, Paweł; Paradowska, Katarzyna; Bukowicki, Jarosław

    2017-10-01

    Capsaicin produced by plants from genus Capsicum exerts multiple pharmacological effects and has found applications in food and pharmaceutical industry. The alkaloid was studied by a combined approach: solid-state NMR, GA conformational search and GIAO DFT methods. The 13C CPMAS NMR spectra were recorded using variable contact time and dipolar dephasing experiments. The results of cross-polarization (CP) kinetics, such as TCP values and long T1ρH (100-200 ms), indicated that the capsaicin molecule is fairly mobile, especially at the end of the aliphatic chain. The15N MAS NMR spectrum showed one narrow signal at -255 ppm. Genetic algorithm (GA) search with multi modal optimization was used to find low-energy conformations of capsaicin. Theoretical GIAO DFT calculations were performed using different basis sets to characterize five selected conformations. 13C CPMAS NMR was used as a validation method and the experimental chemical shifts were compared with those calculated for selected stable conformers. Conformational analysis suggests that the side chain can be bent or extended. A comparison of the experimental and the calculated chemical shifts indicates that solid capsaicin does not have the same structure as those established by PWXRD.

  4. Simulation and optimization of stable isotope 13C separation by carbon monoxide cryogenic distillation

    International Nuclear Information System (INIS)

    Li Hulin; Ju Yonglin; Li Liangjun; Xu Dagang

    2009-01-01

    A stable isotope 13 C separation column was set up by carbon monoxide (CO) cryogenic distillation. Diameter of the column is 45 mm, packing height is 17.5 m, of which enriching section is 15 m and stripping section is 2.5 m. Firstly, computer simulation results were validated by test results. Secondly, tests were replaced by computer simulations in order to obtain the optimal operation conditions in the experimental setup. Comprehensive factors of column pressure, feeding velocity, reflux ratio, withdrawing velocity, and boiling power impacts on the products were studied. Then optimization design of the experimental device was achieved through computer simulations combined with uniform experimental design. The final results show that the optimal operation conditions in the built column are as followings: boiling power, 250 W; column pressure, 54 kPa; reflux ratio, 84. The conclusion is that the method of combination of computer simulation and experimental design could be applied to 13 C industrial design and could be popularized in traditional distillation process to realize optimization design. (authors)

  5. 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.

  6. Magnetization and 13C NMR spin-lattice relaxation of nanodiamond powder

    Energy Technology Data Exchange (ETDEWEB)

    Levin, E.M.; Fang, X.W.; Bud' ko, S.L.; Straszheim, W.E.; McCallum, R.W.; Schmidt-Rohr, K.

    2008-02-15

    The bulk magnetization at temperatures of 1.8-400 K and in magnetic fields up to 70 kOe, the ambient temperature {sup 13}C NMR spin-lattice relaxation, T{sub 1,c}, and the elemental composition of three nanodiamond powder samples have been studied. The total magnetization of nanodiamond can be explained in terms of contributions from (1) the diamagnetic effect of carbon, (2) the paramagnetic effect of unpaired electrons present in nanodiamond grains, and (3) ferromagnetic-like and (4) superparamagnetic contributions from Fe-containing particles detected in spatially resolved energy-dispersive spectroscopy. Contributions (1) and (2) are intrinsic to nanodiamond, while contributions (3) and (4) arise from impurities naturally present in detonation nanodiamond samples. {sup 13}C NMR T{sub 1,c} relaxation would be unaffected by the presence of the ferromagnetic particles with the bulk magnetization of {approx} 0.01 emu/g at 300 K. Thus, a reduction of T{sub 1,c} by 3 orders of magnitude compared to natural and synthetic microdiamonds confirms the presence of unpaired electrons in the nanodiamond grains. The spin concentration in nanodiamond powder corresponds to {approx}30 unpaired electrons per {approx}4.6 nm diameter nanodiamond grain.

  7. Metabolite-balancing techniques vs. 13C tracer experiments to determine metabolic fluxes in hybridoma cells.

    Science.gov (United States)

    Bonarius, H P; Timmerarends, B; de Gooijer, C D; Tramper, J

    The estimation of intracellular fluxes of mammalian cells using only mass balances of the relevant metabolites is not possible because the set of linear equations defined by these mass balances is underdetermined. In order to quantify fluxes in cyclic pathways the mass balance equations can be complemented with several constraints: (1) the mass balances of co-metabolites, such as ATP or NAD(P)H, (2) linear objective functions, (3) flux data obtained by isotopic-tracer experiments. Here, these three methods are compared for the analysis of fluxes in the primary metabolism of continuously cultured hybridoma cells. The significance of different theoretical constraints and different objective functions is discussed after comparing their resulting flux distributions to the fluxes determined using 13CO2 and 13C-lactate measurements of 1 - 13C-glucose-fed hybridoma cells. Metabolic fluxes estimated using the objective functions "maximize ATP" and "maximize NADH" are relatively similar to the experimentally determined fluxes. This is consistent with the observation that cancer cells, such as hybridomas, are metabolically hyperactive, and produce ATP and NADH regardless of the need for these cofactors. Copyright 1998 John Wiley & Sons, Inc.

  8. Synthesis of (R,S)-[2,3-13C2]-1-(1'-methyl-2'-pyrrolidinyl)propan-2-one; {(R,S)-[2',3'-13C2]hygrinePound right bracePound

    International Nuclear Information System (INIS)

    Abraham, T.W.; Leete, Edward

    1996-01-01

    2-Ethoxy-1-methyl-5-pyrrolidinone (1) was reacted with ethyl [3,4- 13 C 2 ]-acetoacetate (2) in the presence of TiCl 4 to give ethyl [3,4- 13 C 2 ]-2-(1'-methyl-5'-oxo-2'-pyrrolidinyl)-3-oxobutanoate (3) in 85% yield. Decarboethoxylation of ethyl [3,4- 13 C 2 ]-2-(1'-methyl-5'-oxo-2'-pyrrolidinyl)-3-oxobutan-oate (3) was accomplished using NaCl and H 2 O in DMSO to give (R,S)-[2,3- 13 C 2 ]-1-(1'-methyl-5'-oxo-2'-pyrrolidinyl)propan-2-o ne (4) in 91% yield. Protection of the ketone as a ketal (ethylene glycol, H + ), followed by reduction of the amide to the amine using LiAlH 4 and subsequent deprotection of the ketal gave (R,S)-[2,3- 13 C 2 ]-1-(1'-methyl-2'-pyrrolidinyl)propan-2-one ((R,s)-[2', 3'- 13 C 2 ]Hygrine) (8) in 78% yield. (61% overall yield from ethyl [3,4- 13 C 2 ]acetoacetate). (Author)

  9. CO2 and 12C:13C Isotopic Ratios on Phoebe and Iapetus

    Science.gov (United States)

    Clark, R. N.; Brown, R. H.; Cruikshank, D. P.

    2016-12-01

    Cassini VIMS has obtained spatially resolved 0.35 to 5.1 micron reflectance spectra of Saturn's satellites beginning with the Phoebe fly-by in 2004 and a close fly-by of Iapetus in 2007. Both surfaces contain relatively abundant CO2. The new (2016 RC19) calibration of VIMS has provided a significant increase in the data quality, such that isotopic absorption bands in CO2 are now well defined. CO2 on Saturn's icy satellites is trapped (Cruikshank et al., 2010, Icarus v206 p561; Pinilla-Alonso et al. 2011, Icarus v211, p75i), predominantly in the dark material (Clark et al. 2012, Icarus v218 p831). Clark et al. modeled the CO2 abundance as 2.8% on Iapetus and 3.7% on Phoebe. The main 12CO2 band in VIMS spectra on Iapetus occurs at 4.253 microns and Phoebe at 4.266 microns. The 13CO2 absorption is strong on Phoebe at 4.367 microns and weak on Iapetus at 4.387 microns. Converting the Phoebe, Iapetus, and a lab reflectance spectrum (of trace H2O-CO2 mixture on a diffuse substrate), we derive preliminary values for the ratio of the equivalent widths of the 12C and 13C absorptions as 19±2 on Phoebe, 82±8 on Iapetus, and 98±10 for the laboratory spectrum. These ratios are related to the 12C/13C ratio, but there may be effects due to intra-molecular and inter-molecular coupling that will contribute to systematic errors in the isotopic abundances derived using equivalent-width measurements that we've yet to quantify. We Believe the effects are small, and will be attempting to quantify them in the future. For comparison, the terrestrial value of the 12C/13C ratio is 90.17, and vibrational coupling may explain the slightly high lab mixture result. The local interstellar medium is 69±15 (Boogert et al., 2000, A&A). Because the CO2 bands on Phoebe and Iapetus dark material have different positions, and because the observed 13C absorption strengths are so different, the surface evolutions must be different. The large enrichment in 13C on Phoebe argues for significant

  10. The fluorine destruction in stars: First experimental study of the {sup 19}F(p,{alpha}){sup 16}O reaction at astrophysical energies

    Energy Technology Data Exchange (ETDEWEB)

    La Cognata, M.; Mukhamedzhanov, A.; Spitaleri, C.; Indelicato, I.; Aliotta, M.; Burjan, V.; Cherubini, S.; Coc, A.; Gulino, M.; Hons, Z.; Kiss, G. G.; Kroha, V.; Lamia, L.; Mrazek, J.; Palmerini, S.; Piskor, S.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S. [INFN-LNS, Catania (Italy); Cyclotron Institute, Texas A and M University, College Station, Texas (United States); University of Catania and INFN-LNS, Catania (Italy); and others

    2012-11-12

    The {sup 19}F(p,{alpha}){sup 16}O reaction is an important fluorine destruction channel in the proton-rich outer layers of asymptotic giant branch (AGB) stars and it might also play a role in hydrogendeficient post-AGB star nucleosynthesis. So far, available direct measurements do not reach the energy region of astrophysical interest (E{sub cm}{approx} 300 keV), because of the hindrance effect of the Coulomb barrier. The Trojan Horse (TH) method was thus used to access this energy region, by extracting the quasi-free contribution to the {sup 2}H({sup 19}F,{alpha}{sup 16}O)n reaction. The TH measurement of the {alpha}{sub 0} channel, which is the dominant one at such energies, shows the presence of resonant structures not observed before that cause an increase of the reaction rate at astrophysical temperatures up to a factor of 1.7, with potential important consequences for stellar nucleosynthesis.

  11. Certified Reference Material for Use in 1H, 31P, and 19F Quantitative NMR, Ensuring Traceability to the International System of Units.

    Science.gov (United States)

    Rigger, Romana; Rück, Alexander; Hellriegel, Christine; Sauermoser, Robert; Morf, Fabienne; Breitruck, KathrinBreitruck; Obkircher, Markus

    2017-09-01

    In recent years, quantitative NMR (qNMR) spectroscopy has become one of the most important tools for content determination of organic substances and quantitative evaluation of impurities. Using Certified Reference Materials (CRMs) as internal or external standards, the extensively used qNMR method can be applied for purity determination, including unbroken traceability to the International System of Units (SI). The implementation of qNMR toward new application fields, e.g., metabolomics, environmental analysis, and physiological pathway studies, brings along more complex molecules and systems, thus making use of 1H qNMR challenging. A smart workaround is possible by the use of other NMR active nuclei, namely 31P and 19F. This article presents the development of three classes of qNMR CRMs based on different NMR active nuclei (1H, 31P, and 19F), and the corresponding approaches to establish traceability to the SI through primary CRMs from the National Institute of Standards and Technology and the National Metrology Institute of Japan. These TraceCERT® qNMR CRMs are produced under ISO/IEC 17025 and ISO Guide 34 using high-performance qNMR.

  12. Preliminary 19F-MRS Study of Tumor Cell Proliferation with 3′-deoxy-3′-fluorothymidine and Its Metabolite (FLT-MP

    Directory of Open Access Journals (Sweden)

    In Ok Ko

    2017-01-01

    Full Text Available The thymidine analogue 3′-deoxy-3′-[18F]fluorothymidine, or [18F]fluorothymidine ([18F]FLT, is used to measure tumor cell proliferation with positron emission tomography (PET imaging technology in nuclear medicine. FLT is phosphorylated by thymidine kinase 1 (TK1 and then trapped inside cells; it is not incorporated into DNA. Imaging with 18F-radiolabeled FLT is a noninvasive technique to visualize cellular proliferation in tumors. However, it is difficult to distinguish between [18F]FLT and its metabolites by PET imaging, and quantification has not been attempted using current imaging methods. In this study, we successfully acquired in vivo F19 spectra of natural or nonradioactive 3′-deoxy-3′-fluorothymidine ([19F]FLT and its monophosphate metabolite (FLT-MP in a tumor xenograft mouse model using 9.4T magnetic resonance imaging (MRI. This preliminary result demonstrates that 19F magnetic resonance spectroscopy (MRS with FLT is suitable for the in vivo assessment of tumor aggressiveness and for early prediction of treatment response.

  13. IsoDesign: a software for optimizing the design of 13C-metabolic flux analysis experiments.

    Science.gov (United States)

    Millard, Pierre; Sokol, Serguei; Letisse, Fabien; Portais, Jean-Charles

    2014-01-01

    The growing demand for (13) C-metabolic flux analysis ((13) C-MFA) in the field of metabolic engineering and systems biology is driving the need to rationalize expensive and time-consuming (13) C-labeling experiments. Experimental design is a key step in improving both the number of fluxes that can be calculated from a set of isotopic data and the precision of flux values. We present IsoDesign, a software that enables these parameters to be maximized by optimizing the isotopic composition of the label input. It can be applied to (13) C-MFA investigations using a broad panel of analytical tools (MS, MS/MS, (1) H NMR, (13) C NMR, etc.) individually or in combination. It includes a visualization module to intuitively select the optimal label input depending on the biological question to be addressed. Applications of IsoDesign are described, with an example of the entire (13) C-MFA workflow from the experimental design to the flux map including important practical considerations. IsoDesign makes the experimental design of (13) C-MFA experiments more accessible to a wider biological community. IsoDesign is distributed under an open source license at http://metasys.insa-toulouse.fr/software/isodes/ © 2013 Wiley Periodicals, Inc.

  14. Turnover of carbon in the {sup 13}C-urea breath test for the detection of Helicobacter pylori infection

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Vladimir E.; Andreazzi, Mariana; Cury, Caio S.; Bassetto Junior, Carlos A.Z.; Rodrigues, Maria A.M.; Ducatti, Carlos, E-mail: vladimir@ibb.unesp.br, E-mail: ducatti@ibb.unesp.br, E-mail: mariana.andreazazi@gmail.com, E-mail: caiocury@hotmail.com, E-mail: juniorbassett@hotmail.com, E-mail: mariar@fmb.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil)

    2013-07-01

    To obtain a standard protocol for the application of {sup 13}C-urea breath test ({sup 13}C-UBT) analyzed by Isotope Ratio Mass Spectrometer (IRMS) to detect helicobacter pylori infection in the population is necessary to know the behavior of the turnover of {sup 13}C during the test in different individuals. The aims of this study was to find out a pattern for the turnover of the {sup 13}C in the {sup 13}C-UBT, analyzed by IRMS, in patients infected with H. pylori, in a Brazilian population, to define a protocol test application. We found that the isotopic ratio {sup 13}C/{sup 12}C in expired CO{sub 2} from patients infected with H. pylori and subjected to {sup 13}C-UBT does not follow a single pattern of behavior. However this behavior can be similar in subjects having the same maximum values following an inverse proportional relationship between the maximum value and the time of appearance in the curve. (author)

  15. 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)

  16. Soil Organic δ13C Change Along a Vertical Gradient in the Northern Slop of Tianshan Mountains

    Directory of Open Access Journals (Sweden)

    XU Wen-qiang

    2016-09-01

    Full Text Available Soil organic carbon (SOC pool integrated the vegetation succession information from several years to thousands of years scales. It is an ideal tool to understand carbon isotope composition change and terrestrial ecosystem pathways. In this study, the Sangong river watershed was taken as a case. We had estimated the change of vegetation and soil organic along a vertical gradient using the carbon isotopic method, and analyzed the variations of mean SOC δ13C values with the annual precipitation, and researched the variations in SOC and δ13C values with profile depth in the study area. The results showed that the SOC δ13C decreased significantly with the increasing annual precipitation (R2=0.97 where the annual precipitation was less than 300 mm. When the annual precipitation was 300 mm~500 mm, the SOC δ13C was not significant changed with the increasing annual precipitation (R2=0.04. The enrichment effect of SOC δ13C with depth was significant in the sample site of pure C3 vegetation, that means lower layer SOC δ13C of profile was greater than the upper layer. The average difference of SOC δ13C between lower layer and upper layer was 1.01‰. The opposite trend of SOC δ13C was presented in the Desert and Shrubland sites. And that, the SOC δ13C value of upper layer closed to C4 vegetation source, and the lower layer closed to C3 vegetation source. Therefore, we can infer that the vegetation may have experienced from C3 to C4 in the sandy desert and terrene desert sites.

  17. Hyperpolarized 13C MR imaging detects no lactate production in mutant IDH1 gliomas: Implications for diagnosis and response monitoring

    Directory of Open Access Journals (Sweden)

    Myriam M. Chaumeil

    2016-01-01

    Full Text Available Metabolic imaging of brain tumors using 13C Magnetic Resonance Spectroscopy (MRS of hyperpolarized [1-13C] pyruvate is a promising neuroimaging strategy which, after a decade of preclinical success in glioblastoma (GBM models, is now entering clinical trials in multiple centers. Typically, the presence of GBM has been associated with elevated hyperpolarized [1-13C] lactate produced from [1-13C] pyruvate, and response to therapy has been associated with a drop in hyperpolarized [1-13C] lactate. However, to date, lower grade gliomas had not been investigated using this approach. The most prevalent mutation in lower grade gliomas is the isocitrate dehydrogenase 1 (IDH1 mutation, which, in addition to initiating tumor development, also induces metabolic reprogramming. In particular, mutant IDH1 gliomas are associated with low levels of lactate dehydrogenase A (LDHA and monocarboxylate transporters 1 and 4 (MCT1, MCT4, three proteins involved in pyruvate metabolism to lactate. We therefore investigated the potential of 13C MRS of hyperpolarized [1-13C] pyruvate for detection of mutant IDH1 gliomas and for monitoring of their therapeutic response. We studied patient-derived mutant IDH1 glioma cells that underexpress LDHA, MCT1 and MCT4, and wild-type IDH1 GBM cells that express high levels of these proteins. Mutant IDH1 cells and tumors produced significantly less hyperpolarized [1-13C] lactate compared to GBM, consistent with their metabolic reprogramming. Furthermore, hyperpolarized [1-13C] lactate production was not affected by chemotherapeutic treatment with temozolomide (TMZ in mutant IDH1 tumors, in contrast to previous reports in GBM. Our results demonstrate the unusual metabolic imaging profile of mutant IDH1 gliomas, which, when combined with other clinically available imaging methods, could be used to detect the presence of the IDH1 mutation in vivo.

  18. High Field In Vivo 13C Magnetic Resonance Spectroscopy of Brain by Random Radiofrequency Heteronuclear Decoupling and Data Sampling

    Science.gov (United States)

    Li, Ningzhi; Li, Shizhe; Shen, Jun

    2017-06-01

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

  19. Complete 1H and 13C NMR assignments and anti fungal activity of two 8-hydroxy flavonoids in mixture

    International Nuclear Information System (INIS)

    Johann, Susana; Smania Junior, Artur; Branco, Alexsandro

    2007-01-01

    A mixture of the two new flavonols 8-hydroxy-3, 4', 5, 6, 7-pentamethoxyflavone (1) and 8-hydroxy-3, 3', 4', 5, 6, 7-hexamethoxyflavone (2) was isolated from a commercial sample of Citrus aurantifolia. An array of one- ( 1 H NMR, { 1 H} -13 C NMR, and APT -13 C NMR) and two-dimensional NMR techniques (COSY, NOESY, HMQC and HMBC) was used to achieve the structural elucidation and the complete 1 H and 13 C chemical shift assignments of these natural compounds. In addition, the antifungal activity of these compounds against phytopathogenic and human pathogenic fungi was investigated. (author)

  20. Glasshouse seedling δ13C and canopy δ13C of 8-year-old hoop pine families grown in south-east Queensland in relation to canopy δ18O, nitrogen concentration and tree growth

    International Nuclear Information System (INIS)

    Prasolova, N.V.; Saffigna, P.G.; Farquhar, G.D.

    1999-01-01

    Full text: Carbon isotope composition (δ l3 C) in C 3 plants has been theoretically and empirically linked to plant water-use efficiency (WUE). The plant δ 13 C has been suggested as an early selection criterion in plant breeding. The δ 13 C and nitrogen concentration (N mass ) of branchlet tissue for inner and outer upper canopy positions were assessed for 8-year-old hoop pine (Araucaria cunninghamii Ait.ex D.Don) trees from 23 half-sib families grown in 5 blocks of a progeny test in south-east Queensland, and for glasshouse seedlings. Tree height was positively related to N mass in branchlets of the 2 canopy positions, indicating that tree growth was limited by nitrogen deficiency. Our data indicated that water supply was also a growth-limiting factor in the hoop pine plantation of the study-area. There were considerable variations in δ 13 C and N mass between families and blocks in the field (with a heritability estimate of 0.73 for branchlet δ 13 C from the inner canopy position). Significant variation in δ 13 C was observed between positions and families of the glasshouse seedlings (with a heritability estimate of 0.66). There was also a significant difference in N mass between the 2 sampling positions in the field. The δ 13 C was positively related to N mass for the branchlets of the upper outer crown (r=0.62, p 13 C (r: 0.28-0.41, p l3 C of the 2 canopy positions for all the 115 trees sampled. There was no significant correlation between δ 13 C values for 2 seedling canopy positions at age 18 months, possibly due to restricted rooting conditions in small pots, leading to greater stomatal closure in upper canopy, which was also reflected in more positive δ 13 C. Significant correlation existed between seedling δ 13 C of upper canopy position at age 8 months and low canopy position at age 18 months. This, together with field data, demonstrated the sensitivity and reliability of δ 13 C as an indicator of plant growth environment. Strong correlation

  1. A 13C NMR Study of 7-Norbornadienyl Cation by Modified Hammett-Brown Equation

    International Nuclear Information System (INIS)

    Park, Jeong Kyu; Shin, Jung Hyu

    1999-01-01

    A series of the para-substituted 7-aryl-norbornadienyl cation (3) was prepared in FSO 3 H/SO 2 ClF solution at -100 .deg. C and their 13 C NMR shifts were measured at -80 .deg. C. The plots of the chemical shifts (changes in chemical shifts) of cationic carbon, Δδ C+ , against our calculated new substituent constant, σ c+ s, gave an excellent correlation (r = 0.994), with a p c+ value of 12.63. These results indicate that the new substituent onstants, σ c+ s, can be successfully employed to compare the relative charge demand of the carbonium ion by π- and πσ-participation

  2. 13C and 29Si NMR as a probe to investigate polysiloxanes used in dental applications

    International Nuclear Information System (INIS)

    Silva, Naira Machado da; Tavares, Maria Ines B.

    2001-01-01

    The properties of dental mould polymeric materials are strongly influenced by the chemical structure of both the polymer and the catalyst used in the crosslink reaction between them. In order to characterize and suggest some modifications on the materials interfacial interactions, mixtures of Polymer-catalyst were prepared. The polymer and the catalyst chemical structures were obtained by 13 C, 1 H and 129 Si NMR analysis in solution state. From the solution NMR results it was obtained the structure of the polymer and the catalyst and also the kind of the crosslink reaction taken. The CPMAS 1 '3C NMR analysis in the solid state were used to identify chemical structure of the polymeric dental moulded sample. (author)

  3. Turnover of soil organic matter under pasture as determined by 13C natural abundance

    International Nuclear Information System (INIS)

    Skjemstad, J.O.; Prebble, R.E.; Feuve, R.P.

    1990-01-01

    The change in vegetation cover from rainforest with a C 3 photosynthetic pathway to grasses with C 4 pathways was used to follow input rates and turnover of organic matter in a krasnozem over an 83 year period. The measurement of δ 13 C values on soils from three depths (0.0-7.5, 7.5-15.0, 60.0-80.0 cm) indicated that charcoal was a serious contaminant in the light fractions ( 1.6 Mg m -3 fraction from the three depths were calculated as 60, 75 and 276 years respectively, compared with 75, 108 and 348 years for the organic matter within microaggregates from the same horizons. It is concluded that the presence of microaggregates is an important factor in stabilizing organic matter in this soil type. Some difficulties with the technique are also discussed. 36 refs., 2 figs., 4 tabs

  4. Two-dimensional NMR spectroscopy of 13C methanol at less than 5 μT

    Science.gov (United States)

    Shim, Jeong Hyun; Lee, Seong-Joo; Hwang, Seong-min; Yu, Kwon-Kyu; Kim, Kiwoong

    2014-09-01

    Two-dimensional (2D) spectroscopy is one of the most significant applications of nuclear magnetic resonance (NMR). Here, we demonstrate that the 2D NMR can be performed even at a low magnetic field of less than 5 μT, which is ten times less than the Earth’s magnetic field. The pulses used in the experiment were composed of circularly polarized fields for coherent as well as wideband excitations. Since the excitation band covers the entire spectral range, the simplest two-pulse sequence delivered the full 2D spectrum. At 5 μT, methanol with 13C enriched up to 99% belongs to a strongly coupled regime, and thus its 2D spectrum exhibits complicated spectral correlations, which can be exploited as a fingerprint in chemical analysis. In addition, we show that, with compressive sensing, the acquisition of the 2D spectrum can be accelerated to take only 45% of the overall duration.

  5. Fission fragment mass distribution in the 13C+182W and 176Yb reactions

    International Nuclear Information System (INIS)

    Ramachandran, K.; Hinde, D.J.; Dasgupta, M.; Williams, E.; Wakhle, A.; Luong, D.H.; Evers, M.; Carter, I.P.; Das, S.

    2014-01-01

    Fission fragment mass distributions have been measured