Results 251 to 260 of about 1,099,567 (306)

Automatic Cascade for the Production of Nitrogen-15

Industrial & Engineering Chemistry, 1959
BS>A small automatic isotope separation cascade was constructed and operated to evaluate the use of the HNO/sub 3/-NO chemical exchange reaction as a method of separating nitrogen-15 on a large-scale basis. Successful operation of the cascade over a long period of time demonstrated the technical feasibility of the chemical process and the cascade ...
G. M. Begun, J. S. Drury, E. F. Joseph
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Nitrogen-15 magnetic resonance spectroscopy. XIV. Natural-abundance nitrogen-15 chemical shifts of amines

Journal of the American Chemical Society, 1972
It has been found possible to measure the shifts of a variety of amines to an accuracy of 0.2 ppm with the isotope at its natural-abundance level. Successful observation of these resonances with our existing equipment is dependent on a favorable nuclear Overhauser effect arising from irradiation of the protons.
Lichter, Robert L., Roberts, John D.
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Nitrogen‐15 NMR spectroscopy: Nitrogen‐15 chemical shifts of 1,2‐diaminobenzenes and 1,8‐diaminonaphthalenes

Magnetic Resonance in Chemistry, 1991
AbstractNitrogen‐15 chemical shifts of 1,2‐diaminobenzenes, 1,8‐diaminonaphthalenes and their monoprotonated species are reported.
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Nitrogen‐15 Variations in Fertilizer Nitrogen

Journal of Environmental Quality, 1974
AbstractNitrogen‐15 concentrations of some commonly used nitrogen fertilizers are measured. Ammonium‐nitrogen has lower and nitrate‐nitrogen has higher 15N concentrations than atmospheric nitrogen. The mean difference between both is about 4 δ 15N.
H. D. Freyer, A. I. M. Aly
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A nitrogen-15 spin-lattice relaxation study of alumichrome

Biochimica et Biophysica Acta (BBA) - Protein Structure, 1978
Abstract 15N-NMR spectra of a 0.07 M solution of 99.2% 15N-enriched alumichrome in [2H6]Me2SO were recorded at 10.13 MHz. The signals of all the nine nitrogens in this molecule were well resolved. The chemical shifts of the six peptide backbone resonances show good agreement with values previously determined on the basis of indirect 1H-{15N ...
M, Llinás, K, Wüthrich
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Turnover of Nitrogen-15-Labeled Fertilizer in Old Grassland

Soil Science Society of America Journal, 2004
In this paper we follow the fate of single applications of 15 N‐labeled fertilizer to old grassland, over a period of nearly 20 yr. In 1980 and 1981, 15 N‐labeled N was applied to two of the treatments on the Park Grass Continuous Hay Experiment at ...
D. S. Jenkinson, P. R. Poulton, A. E. Johnston, D. S. Powlson   +3 more
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Nitrogen-15 nuclear magnetic resonance studies of porphyrins

Journal of the American Chemical Society, 1977
The ^(15)N NMR spectra of meso-tetraphenylporphyrin, its dication, and zinc tetraphenylporphyrin have been investigated both at the natural-abundance level and with isotopic enrichment. The resonances of tetraphenylporphyrin at ambient temperatures are broadened by chemical exchange of the central hydrogen atoms.
Gust, Devens, Roberts, John D.
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ChemInform Abstract: NITROGEN‐15 CHEMICAL SHIFTS AND CARBON‐13‐NITROGEN‐15 COUPLING CONSTANTS OF CYANIDE COMPLEXES

Chemischer Informationsdienst, 1982
AbstractUntersuchungen an den oktaedrischcn Hexacyanokomplexen [M1(CN)6]4‐(M1: Fe, Ru.
M. SANO, Y. YOSHIKAWA, H. YAMATERA
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Combination of Nitrogen-15-labelled Nitrogen Mustard with Proteins

Nature, 1951
THE nitrogen mustards readily inactivate certain enzymes1 and they also react with many other proteins2, including the components of haemolytic complement3. Although it has been established by various investigators that the amino, sulphydryl, sulphide, carboxyl and pyridine groups of proteins are affected by the action of the nitrogen mustards4, there ...
V C E, BURNOP, D E, RICHARDS, W M, WATKINS, A, WORMALL   +3 more
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A sensitive method for determining nitrogen-15 isotope in urea

Marine Biology, 1997
A method is presented in which the 15N at.% of urea is determined with high precision on liquid samples containing as little as 10 nmol of urea. The method involves removal of interference from NH4 + initially present in the sample by cation exchange. Urea in the sample is subsequently hydrolyzed to NH4
Rysgaard, S.; id_orcid 0000-0003-1726-2958, Risgaard-Petersen, N.   +1 more
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