(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.
Metallurgy
Definition:
(n.) The art of working metals, comprehending the whole process of separating them from other matters in the ore, smelting, refining, and parting them; sometimes, in a narrower sense, only the process of extracting metals from their ores.
Example Sentences:
(1) In 1984 the press-fit condylar knee was first introduced and was intended to provide a condylar knee system primarily for posterior cruciate retention that addressed refinements in metallurgy, prosthetic geometry and sizing, cementless fixation, inventory management, and instrumentation.
(2) Thirteen of the 25 revisions required in the early series were due to stem fracture, a complication rarely seen now with improved stem design and superalloy metallurgy.
(3) The authors examined a group of pregnant women employed in metallurgy and in a control group.
(4) The physical and mechanical properties of samples of a nickel-base alloy fabricated by powder metallurgy were determined.
(5) It can also be used for many other applications, for example, in metallurgy, petrography and geostrategy.
(6) in length), having either conventional smooth surfaces (control) or porous surfaces (20 to 50 micron particle size) produced by powder metallurgy techniques, were positioned in the right atrial a-pendage.
(7) An economic evaluation is made on temporary disability because of disease of trauma, for a three-year period in one shop of technological plant for nonferrous metallurgy.
(8) Archaeological and anthropological studies of early developments in writing, music and metallurgy by ancient Peruvians and Persian peoples should be combined with PET-scan studies of their descendants to discover if, as preliminary archaeological data suggest, the two ancient populations differed on a genetic basis in higher brain functions, yet are indistinguishable as metallurgical engineers.
(9) Subjects ranged from maths to metallurgy and modern languages.
(10) Metallurgical occupational hazards harm the health status in workers engaged into heat-treating metallurgy, induce the gastrointestinal disorders, which are demonstrated by the elevated transitory disablement.
(11) Basing on complex physiological and hygienic studies, the contributors propose an assessment of the work load of those engaged in the major professions in copper and nickel metallurgy.
(12) She grew up in Norilsk, a Siberian mining and metallurgy city that was once the centre of the Norillag gulag and one of the 10 most polluted places on earth.
(13) Transitory disablement in 5886 workers engaged for the whole year into heat treating metallurgy was compared during 5 years (1981-1985) with that in 291 workers engaged into repairing mechanical occupations so as to reveal metallurgical occupational factors influencing on gastrointestinal morbidity.
(14) Aluminium metal high-disperse dust presents a major health-affecting factor in aluminium powder metallurgy.
(15) In order to accurately evaluate copper exposure at working places where copper fume may arise (Metallurgy Department) it is necessary to determine Cu concentrations in respirable dust.
(16) These are as follows: ferrous metallurgy (5.21), metals producing industry (4.88), textile industry (4.83), chemical industry (4.63) and rubber processing industry (4.73).
(17) The origins of metallurgy stretch back nearly 4,000 years in South America.
(18) Working environment has been evaluated in two copper metallurgy plants by analysis of Cu and other metals (Pb, Cd, Zn) concentrations.
(19) Incidence of multiple myeloma was significantly increased for a number of occupational groups such as farmers, smelter and metallurgy workers, and miners-quarrymen-rock blasters.
(20) The attention is directed to regions with national industrial branches, most intensively polluting the atmospheric air (metallurgy, chemistry, petroleum-chemistry, cellulose-paper industry) and such, where the air pollution is related first of all to transport across the border-line.