(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.
Propylene
Definition:
(n.) A colorless gaseous hydrocarbon (C3H6) of the ethylene series, having a garlic odor. It occurs in coal gas, and is produced artificially in various ways. Called also propene.
Example Sentences:
(1) CZP reduced the incidence of convulsions only after the larger dose, but plain solvent (propylene glycol, ethanol, water) was equally effective.
(2) A hemolytic reaction, probably due to the propylene glycol in the solution, was seen in one case.
(3) At initial concentrations of 0.1 and 1.0 M, glycerin and propylene glycol increase significantly the intestinal absorption rate of theophylline from the small intestine of anesthetized rats.
(4) Therapeutic application of drugs containing propylene glycol 1.2 as a solvent may distort the results of forensic chemical detection of ethylene glycol from its oxidation products.
(5) Practical examples illustrate the possibility of ethylene glycol determination by gas chromatography in the presence of propylene glycol.
(6) Experimental data are presented for: (a) the flux of diflorasone diacetate through hairless mouse skin, (b) the percutaneous penetration profile of propylene glycol, (c) the effects of vehicle concentrations of polyoxypropylene 15 stearyl ether and propylene glycol on the percutaneous flux of diflorasone diacetate, (d) skin--vehicle partition coefficients of diflorasone diacetate, (e) the solubility profile of diflorasone diacetate as a function of solvent concentration, and (f) the alteration of the skin's resistance to the penetration of diflorasone diacetate due to propylene glycol.
(7) Dehydration in ethanol and propylene oxide produces a further 10% shrinkage in volume.
(8) Propylene glycol (PG) is widely used as a drug solvent in the pharmaceutical industry.
(9) Propylene glycol was less effective than polyethylene glycol 400.
(10) On the other hand, propylene glycol, an alcohol sulfotransferase inhibitor, had a profound inhibitory effect on DNA methylation induced by NMHEA, very little effect on the formation of N7-(2-hydroxyethyl)guanine, but a very strong effect on the O6-hydroxyethylguanine lesions.
(11) The SCE frequency was more than doubled in the cultures treated with ethylene oxide and propylene oxide; methyl bromide also induced SCEs.
(12) However, propylene glycol was found to depress all the levels of alkylation in the brachymorphic mice, except for N7-(2-hydroxyethyl)guanine, as was observed in rats.
(13) Of these, 11 were positive to propantheline bromide, 3 to trichlorocarbanilide and one to propylene glycol.
(14) A method for monitoring exposure to ethylene oxide (EO) and propylene oxide (PO) and their corresponding alkenes through the analysis of adducts to N-terminal valine in hemoglobin (Hb) using gas chromatography (GC) and electron-capture detection has been developed.
(15) The CK activity was measured in muscle tissue taken from the injected area (dorsal longissimus muscle) and the contralateral side of the injection site 72 hours after intramuscular injection into rabbits of 1 ml of different dilutions of propylene glycol or glycerol formal in distilled water or 0.9% saline.
(16) We found the application of propylene glycol alone to produce no epidermal changes.
(17) After inhalation exposure, 1,2-epoxybutane was carcinogenic in rodents as were other epoxides or related compounds including propylene oxide, 1,3-butadiene, and ethylene oxide.
(18) The rats received propylene glycol alone (control) or with Actinomycin-D (Act-D) at 08.00 h, followed by EB at 12.00 h on day 3.
(19) Israeli Friesian cows in the third or later lactation, were injected intramuscularly with 1 alpha-hydroxyvitamin D3 in propylene glycol.
(20) Addition of protease inhibitors, phenylmethyl sulfonyl fluoride (PMSF) and ethylenediamine tetra-acetic acid (EDTA), to subzero (-10 degrees C) fixation with propylene glycol and formaldehyde provides reproducible preservation of immunoreactive AII.