(n.) A gaseous compound of carbon and hydrogen, in the proportion of two atoms of the former to two of the latter. It is a colorless gas, with a peculiar, unpleasant odor, and is produced for use as an illuminating gas in a number of ways, but chiefly by the action of water on calcium carbide. Its light is very brilliant.
Example Sentences:
(1) Optimum rates of acetylene reduction in short-term assays occurred at 20% O2 (0.2 atm (1 atm = 101.325 kPa] in the gas phase.
(2) On siratro, CIAT899 induced nodules that were ineffective in acetylene reduction, whereas the EPS-deficient mutants induced effective nodules.
(3) It is suggested that acetylene reduction assays may not be accurately applied to samples containing methane oxidizing bacteria.
(4) Biological nitrogen fixation, as determined by acetylene reduction, occurs in Lake Erie.
(5) Some of the thiophenes and their acetylenic derivatives possess extremely potent phototoxic activities toward membrane-containing viruses.
(6) The efficiencies of the different positional isomers in supporting cell proliferation varied from essentially 0 cells per fmol for the 2-5 and 13-17 isomers to high values when the acetylenic bond was near the center of the chain: e.g.
(7) If the cultures were grown in media with NH4+, NO3-, urea, glutamine or asparagine, hydrogen photoevolution by the cells and acetylene reduction started after the lag-phase and proceeded at a low rate.
(8) Under suitable growth conditions the acetylenic acids are catabolized and partly reused via acetate for de novo synthesis of fatty acids.
(9) 2-Ethynyl-4,5-diphenylthiazoles were synthesized by the palladium catalyst cross-coupling reaction of 2-iodo-4,5-diphenylthiazole with monosubstituted acetylenes.
(10) The conditions which are necessary for the synthesis and function of this system were studied in whole cells by using acetylene reduction as a sensitive assay for the presence of the N(2)-fixing system.
(11) However, in culture under aerobic conditions, large, phase-bright vesicles are formed in HFPCcI3 within 20 h following removal of NH+4 from the culture medium and reach peak numbers within 72 to 96 h. In vivo acetylene reduction activity parallels vesicle formation.
(12) Vesicles permeabilized by freeze-thaw or detergents showed increased rates of acetylene reduction due to increased permeability of dithionite.
(13) After 30 minutes at this new driving force, four timed acetylene samples were again collected.
(14) 3-(1,2,3-Triazol-1-yl)methylcephalosporins have been prepared by the direct cycloaddition of acetylene to 3-azidomethylcephalosporins, which were obtained by nucleophilic substitution of 3-chloromethylcephalosporins with sodium azide in N,N-dimethylformamide.
(15) Biological dinitrogen fixation in mangrove communities of the Tampa Bay region of South Florida was investigated using the acetylene reduction technique.
(16) Nitrate reductase (nar) A, B and E mutants of Escherichia coli with plasmids carrying Klebsiella pneumoniae nitrogen fixation (nif) genes reduced acetylene independently of added molybdate, but nar D mutants showed pleiotropic dependence on the concentration of added molybdate for expression of both nar and nif.
(17) Two important side reactions of this procedure are known: the formation of the isomeric beta-ethynyl derivative and the formation of a dimeric product with acetylene bridge.
(18) Acetylene-reducing activity of purified nitrogenase from Klebsiella pneumoniae was studied over a range of ATP and Mg(2+) concentrations at 15 degrees C, pH7.8.
(19) The reconstituted acid mixture is injected into the graphite tube atomizer for analysis of Cu and Cd and aspirated into the air--acetylene flame for measurement of Zn.
(20) The 19-acetylenic testosterone, a confirmed metabolite from primate studies, was 25% as efficient as MDL 18,962 for aromatase inactivation, while 6 beta-hydroxy- and 6-oxo analogs were 11% and 5%, respectively as efficient as their parent compound.
Iupac
Definition:
Example Sentences:
(1) The concentrations of the isomers 2,4,4'5-tetraCB (IUPAC 74), 2,2',4,4',5,5'-hexaCB (IUPAC 153), 2,2',3,4,4'5'-hexaCB (IUPAC 138), 2,3,3',4,4',5-hexaCB (IUPAC 156), 2,2',3,4,4',5',6-heptaCB (IUPAC 183), and 2,2',3,3',4,4',5-heptaCB (IUPAC 171) showed close correlation, the coefficients varied from 0.42 to 0.98.
(2) Consequently, IUPAC suggests this procedure as a recommended method.
(3) In Pseudomonas aeruginosa c-551 the 13-propionate (IUB-IUPAC porphyrin nomenclature) has been assigned a pKa of 3.1, and the 17-propionate a pKa of 7.2.
(4) Formaldehyde (IUPAC name, methanal) is one of the simplest, most ubiquitous molecules in our environment and troposphere.
(5) One pathway permits a fast descent to the atomic structure in terms of correct IUPAC carbon atom occurrence numbers.
(6) The congeners were 28, 52, 101, 118, 153, 138, 180, 170, and 209 (IUPAC numbering system, Ballschmiter and Zell 1980).
(7) About 70% of the PCB residues in the sample analysed consisted of only three congeners: 2,2',4,4',5,5' (IUPAC No.
(8) Concentrations of ten toxic coplanar PCBs (IUPAC Nos.
(9) A chemical substance database, containing chemical structures generated automatically from their IUPAC systematic names, is described.
(10) In the present study, a definition of the reference values of blood cadmium (Cd-B) and urinary cadmium (Cd-U) was attempted, adopting the same methodology as that used for Hg-B by ICOH and IUPAC.
(11) the tautomer having a proton bound to the nitrogen atom at position 1 of the ring, where the ring is numbered according to IUPAC-IUB convention) can be calculated from the following equation: XII congruent to 1.705--0.164 3J(C5,H2)obs.
(12) The IUPAC torsional parameters for 100 conformations are illustrated using a wheal and a dial systems.
(13) The investigated yeasts grown on carbohydrates keep the limit of 5 ppb benzo(a)-pyrene recommended by the IUPAC.
(14) One duplicated hexokinase (4a and 4b according to the IUPAC-nomenclature) was detected in rabbit erythrocytes as also described for human erythrocytes.
(15) The IUPAC name is: N-[-1'-(2''-amino-4''-hydroxy-7''-proton-6''-pteridinyl)ethyl]-4- [2',3',4',5'-tetrahydroxypent-1'-yl(5'----1'')O-alpha- ribofuranosyl-5''-phosphoric acid]aniline, in which the phosphate group is esterified with alpha-hydroxyglutarylglutamylaspartic acid.
(16) An international collaborative study of IUPAC methods II.D.19 and II.D.25 for preparation and GLC analysis of fatty acid methyl esters was begun in 1976.
(17) The use of a biodegradable polymer for antigen delivery based on poly(CTTH-iminocarbonate) (IUPAC nomenclature: poly[oxyimidocarbonyloxy-p-phenylene [2-(hexyloxycarbonyl)ethylene]imino[2-[1-(benzyloxy)formamido]- 1-oxotrimethylene]-p-phenylene]) was investigated.
(18) Group 1A contains the three most potent (pure 3-MC-type inducer) congeners, IUPAC numbers 77, 126, and 169.
(19) The results of a collaborative study, stimulated by IUPAC, are reported: Coefficients of variation for the various azaarenes were 4.0-13.6% for the check analysis and 10.4-25.4% for a spiked ham sample.
(20) The conformational parameters are in accordance with the IUPAC-IUB Joint Commission on Biochemical Nomenclature [Pure Appl.