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151.
Summary The direct effect of any antituberculotics on pancreatic lipase was studied by the modified method ofWillstätter. The antituberculotics were found to activate the pancreatic lipase in the presence of Ca++. Any cations, especially copper, decreases the lipase activity. Increasing antituberculotics concentration is accompanied by an increasing effect on the lipolytic action of lipase. 相似文献
152.
Influence of mitotic activity on neurulation movements 总被引:1,自引:0,他引:1
153.
Reaction of gold with collagen in vivo 总被引:1,自引:0,他引:1
154.
155.
Zusammenfassung Aus den Biberdrüsen wurdecis-Cyclohexan-1,2-diol isoliert und charakterisiert.
The support of this work by the Colombo Plan administration of Canada is gratefully acknowledged. 相似文献
The support of this work by the Colombo Plan administration of Canada is gratefully acknowledged. 相似文献
156.
157.
Z.L.Ren D.D.Lu Z.Q.Lei 《复旦学报(自然科学版)》2007,(5)
1 Results Polylactide or polylactic acid (PLA) and poly(lactic-co-glycolic acid) (PLGA) have been utilized as bioabsorbable materials in the medical and pharmaceutical fields due to their biodegradable and biocompatible properties[1].However,due to its hydrophobicity and free carboxylic group,PLA or PLGA was not suitable for use to encapsulate the protein.Recently,poly (ε-caprolactone) and poly (D,L-lactide) were respectively grafted onto hydrophilic dextrin and gelatin to obtain the amphiphilic biodeg... 相似文献
158.
Pathway selection by growth cones of identified motoneurones in live zebra fish embryos 总被引:2,自引:0,他引:2
How is the adult pattern of connections between motoneurones and the muscles that they innervate established during vertebrate development? Populations of motoneurones are thought to follow one of two patterns of development: (1) motor axons initially follow stereotyped pathways and project to appropriate regions of the developing muscle or (2) motor axons initially project to some regions that are incorrect, the inappropriate projections being eliminated subsequently. Here we observed individually identified motoneurones in live zebra fish embryos as they formed growth cones and as their growth cones navigated towards their targets. We report that from axogenesis, each motor axon followed a stereotyped pathway and projected only to the specific region of the muscle appropriate for its adult function. In addition, the peripheral arbor established by each motoneurone was restricted to a stereotyped region of its own segment and did not overlap with the peripheral arbor of the other motoneurones in that segment. We conclude that the highly stereotyped pattern of innervation seen in the adult is due to initial selection of the appropriate pathway, rather than elimination of incorrect projections. 相似文献
159.
Tilman has developed a model to predict the number of plant species that can coexist competitively on a limited resource base. Species diversity first increases over low resource supplies, then declines as the environment becomes richer. Although Tilman 's model was developed to describe interspecific interactions between plant species, it may also apply to animal species. Tilman questions whether animals specialize on particular proportions of nutrients. However, we believe animals probably specialize on relatively subtle microhabitat differences, especially in a multispecies competitive regime. Thus, microhabitats may act like nutrients. We hypothesize that animal species, too, show a peaked curve of diversity over productivity. The present data provide a confirmation of the hypothesis using rodent species. We have investigated the number of rodent species along a geographical gradient of increasing rainfall. The gradient extends from extremely poor desert habitats to those with annual rainfall over 300 mm. Because of the aridity , precipitation reflects productivity. The diversity pattern in desert rodents agrees with that predicted by Tilman for plants. It even possesses similar asymmetry, rising steeply then falling slowly. The pattern is duplicated in rocky and sandy habitats, each of which has a distinct and almost nonoverlapping assemblage of species. As mean precipitation is closely correlated with the variability of precipitation, the diversity pattern might also be caused by a decline in the frequency of disturbances, models for which have been proposed by several investigators. 相似文献
160.
E. G. Popov A. G. Mejlumian I. Yu. Gavrilov Z. A. Gabbasov E. Ya. Pozin 《Cellular and molecular life sciences : CMLS》1988,44(7):616-618
Summary A new approach to the evaluation of the uptake of fluorescent, probes by intact, cells is described. Acridine organe (AO) was used because it can be selectively accumulated by serotonin-containing granules of platelets. Analysis of the fluorescence signal allows the estimation of the relative volume of the granules and the equilibrium coefficients for AO transport across the cytoplasm and granule membranes. The following results were obtained for human and rabbit platelets: the relative volumes of the granules were 14±1% and 29±2%, the ratios of intragranular-extracellular probe concentration were 2260±382 and 30,000±5500, and the cytoplasm-extracellular medium concentration ratios were 375±60 and 225±60, respectively. 相似文献