Results 251 to 260 of about 5,644,306 (315)

Carbon-13 in natural cholesterol

Biological Mass Spectrometry, 1986
In order to assess the feasibility of using stable 13C as a tracer for studying cholesterol metabolism in vivo the 13C content of some commonly consumed foods and the stability of the 13C content of human serum cholesterol has been investigated. A procedure is described for the extraction and purification of cholesterol from food, tissues and serum ...
D, Mendelsohn, A R, Immelman, J C, Vogel, G, von La Chevallerie   +3 more
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Nuclear Transmutations of Carbon-13

Nature, 1950
THIN (∼ 0.05 mgm./cm.2) deposits of carbon-13 prepared electromagnetically at the Atomic Energy Research Establishment, Harwell, have been bombarded by protons and deuterons of energy up to 1 MeV., and observations made on the (pγ)1,2, (dp)3,4, (dα)3 reactions.
C D, CURLING, J O, NEWTON
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Carbon-13 magnetic resonance studies of carbon-13 enriched amino acids

Biochemical and Biophysical Research Communications, 1969
Abstract Carbon-13 magnetic resonance data is presented for carbon-13 enriched L-amino acids. The results are compared to the corresponding proton chemical shifts and discussed in terms of their potential applications to peptides and proteins.
W, Horsley, H, Sternlicht, J S, Cohen
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Carbon‐13 NMR of fluorocyclopropanes

Magnetic Resonance in Chemistry, 2008
AbstractCarbon‐13 and hydrogen NMR data are presented for several cyclopropanes with one to four fluorine atoms attached to the ring. Substituents directly attached to a ring carbon are found to unshield that carbon to an extent increasing with their electronegativity, but remote substituents may have an opposite effect.
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Carbon-13 chemical shifts of benzocycloalkenes

Journal of the American Chemical Society, 1974
Recently Maciel and coworkers reported carbon-13 chemical shift assignments for a number of benzocycloalkenes. The coherent H spin decoupling technique was employed for assignments in indan, benzocyclobutene, benzocyclopropene, and o-di-Zert-butylbenzene, but this necessitated acceptance of the previously reported H aromatic assignments, in no case ...
Adcock W., Gupta B.D., Khor T.C., Doddrell D., Jordan D., Kitching W.   +5 more
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Carbon-13 NMR investigations on ribonuclease A

Biochimica et Biophysica Acta (BBA) - Protein Structure, 1979
The proposed interaction between the amino acid residues Asp 14 and His 48 of ribonuclease A has been confirmed by 13C-NMR spectroscopy. The titration behaviour of the resonance of the side-chain carboxyl group of Asp 14 suggests a pKa of 6.5--7.0 for His 48. An equilibrium between different conformation process of His 48.
J, Santoro, H P, Juretschke, H, Rüterjans   +2 more
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Carbon-13 NMR of Poly(Butadiene)

Rubber Chemistry and Technology, 1972
Abstract By using the carbon-13 NMR technique, it is shown that there are no cis-1,4-trans-1,4 linkages in an n-BuLi-catalyzed poly (butadiene). The polymer consists of “blocks” of cis-1,4 units and trans-1,4 units separated by isolated vinyl units.
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Carbon-13 nuclear magnetic resonance studies of adenosylcobalamin and alkylcorrinoids, selectively enriched with carbon-13

Biochemistry, 1975
The carbon-13 nuclear magnetic resonance spectra of a series of alkylcorrinoids, selectively enriched with 13C in the alkyl ligand, were recorded at 25.2 MHz and 25 degrees. The nature of the axial ligands markedly affects the chemical shift of the labeled alkyl moiety (trans effect) as well as the 13C resonances of selected carbon atoms of the corrin ...
H P, Hogenkamp, R D, Tkachuck, M E, Grant, R, Fuentes, N A, Matwiyoff   +4 more
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Carbon‐13 NMR study of isoxazolopyridine systems

Organic Magnetic Resonance, 1982
AbstractThe 13C NMR spectra of all azabenzenoid isoxazolopyridines and some of their chloro derivatives are discussed. All 13C resonances were unambiguously assigned by means of gated decoupled spectra, from which one‐bond and long‐range 13C1H coupling constants have been determined from line splittings.
CHIMICHI, STEFANO, TEDESCHI, PIERO, A. Camparini, F. Ponticelli   +3 more
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Carbon-13-carbon-13 coupling constants in a series of carbon-13-enriched amino acids

Journal of the American Chemical Society, 1974
John A. Sogn, Lyman C. Craig, William A. Gibbons   +2 more
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