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971.
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F. Clark Howell 《Geobios》1980,13(4):653-657
This attempt at biostratigraphic correlations for the fossiliferous sites of the late Miocene and early Pliocene,situated around the Mediterranean basin, is based on the zones established by P. Mein according to variations in the mammalian faunas. New taxa are mentioned, particularly carnivores; moreover, a series of African localities are integrated and, for some of them, an analysis of the faunal constituents leads to paleobiogeographic considerations. 相似文献
974.
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Enzymatic hydrolysis of the cellulose in raw primary settled municipal sludge by Trichoderma viride cellulase achieved conversions of up to 75% of the cellulose, primarily to cellobiose, in 24 hr. Simultaneously the gel-like characteristic of raw primary sludge was changed to that of a slurry of fine particles in less than 2 hr, causing a radical change in the ability to ultrafilter the sludge. The use of raw primary sludge as a growth medium for T. viride cellulase production was also investigated. It was possible, with nitrogen supplements, to obtain an enzyme with a filter paper activity (FPA) of two compared to over four which is attainable on defined medium of similar strength. The potential use of cellulase treatment as a pretreatment or integral part of waste treatment processes is discussed and the alternatives evaluated. 相似文献
977.
A simple technique using reverse-phase ion-pair liquid chromatography for measurement of exogenous thiosulfate is described. Accurate measurement of thiosulfate in plasma and urine was permitted by precolumn derivatization with monobromobimane, a substance that readily yields fluorescent compounds upon reaction with a variety of biologically important nucleophiles including glutathione, cysteine, and sulfite. Using an injection volume of 50 microliters, as little as 0.16 nmol of thiosulfate was reliably measured. The interassay precision of the method was reflected by a coefficient of variation of 7.7% while the coefficient of variation for interassay analysis was 2.6%. Recovery of thiosulfate from plasma was 96.9 +/- 3.2% and greater than 98% from urine. The simplicity, sensitivity, and precision of the method make it ideal for the study of thiosulfate and other important nucleophiles in body fluids. 相似文献
978.
979.
It is shown that two steady states exist in certain regions of operation of a 2-liter continuous stirred tank biological reactor. Transition was made from one steady state to another by applying shock loads of either phenol substrate which is inhibitory to the culture at high concentrations or by adding large additional amounts of concentrated organisms. The existence of the multiple steady states is ascribed to the existence of wall growth, and their position is determined by the amount of wall growth. Transient behavior of the system did not follow the predictions of the simple wall growth model but the culture appeared to undergo a lag period immediately after applying the shock load to the system. It is concluded that the stability of a continuous culture utilizing an inhibitory substrate is improved by increasing the degree of wall growth and decreasing the substrate feed concentration. It is also concluded that small scale experiments can usually not be interpreted correctly unless the effect of wall growth is taken into account. 相似文献
980.