(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.
Carbide
Definition:
(n.) A binary compound of carbon with some other element or radical, in which the carbon plays the part of a negative; -- formerly termed carburet.
Example Sentences:
(1) The uptake of cobalt by macrophages in the presence of tungsten carbide was found to be increased.
(2) A previous study from this laboratory, using morphological and biochemical (LDH release) parameters, has shown that tungsten carbide-cobalt dust exhibits a greater cytotoxicity toward isolated macrophages than cobalt metal powder alone.
(3) Acceptable finishing procedures for the composite materials tested include silicon carbide disks for accessible areas or 12 fluted finishing burs for more inaccessible areas.
(4) A cross-sectional study of 1,039 tungsten carbide (TC) production workers was carried out.
(5) Experimental measurements have been made of the ultrasonic velocity and attenuation in some simple suspensions of, mainly, silicon carbide in water and in ethylene glycol.
(6) Method 4 comprised a green stone, a carbide finishing bur, and the Vivadent polisher for composite.
(7) It was considered that foreign bodies were composed of carbon steel, steel alloy, and tungsten carbide.
(8) A titanium nitride coating has been deposited on steel and tungsten carbide dental rotary instruments.
(9) On stimulation of the lungs with an inert dust (silicon carbide), the AM count in the BAL and the lung was only slightly increased 8 weeks after intratracheal instillation.
(10) The results showed that the high speed finishing technique by twelve and thirty fluted carbide burs and final polishing with Command Ultrafine Luster Paste produces the smoothest and flatest surface of HERCULITE XR.
(11) Workers in the silicon carbide industry have experienced occupational health diseases, particularly lung disorders such as silicosis.
(12) Finishing with the aid of properly formed diamond stones or tungsten-carbide finishers in the normal speed range 6.
(13) To investigate this, we analyzed pairs of chest radiographs obtained in 1977 and 1984 in 128 silicon carbide plant workers.
(14) For forty years, cases of interstitial pneumonia and bronchial asthma have been described in hard metal workers (i.e., alloys of tungsten carbide and cobalt).
(15) Para-tertiary butylphenol [(PTBP); the Union Carbide Corporation trademark for this chemical is UCAR Butylphenol 4-T Flake] has applications as a raw material in the manufacture of resins and also as an industrial intermediate.
(16) We have previously demonstrated that tungsten carbide-cobalt powder (WC-Co) is more toxic toward murine macrophages in vitro than pure cobalt metal particles and that the cellular uptake of cobalt is enhanced when the metal is present in the form of WC-Co mixture.
(17) Fifty extracted maxillary central incisors were mounted in cups and the facial surfaces of the crowns were polished on 600-grit silicon carbide paper.
(18) The pulpal perforations were treated by partial pulpotomy with a tungsten carbide fissure bur after exposure for 4, 48, or 168 hours in nine animals, and by direct pulp capping after exposure for 4 or 48 hours in the remaining four animals.
(19) There the combination of a preparing diamond cutter with a tungsten carbide finisher proved a success both relating to profiles of enamel bevel after acid etching, small disturbed enamel structure and as to clinical handling.
(20) These observations add further evidence to our previous findings regarding the different biological reactivity of cobalt metal alone or mixed with tungsten carbide.