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271.
272.
Dislocations are line defects that bound plastically deformed regions in crystalline solids. Dislocations terminating on the surface of materials can strongly influence nanostructural and interfacial stability, mechanical properties, chemical reactions, transport phenomena, and other surface processes. While most theoretical and experimental studies have focused on dislocation motion in bulk solids under applied stress and step formation due to dislocations at surfaces during crystal growth, very little is known about the effects of dislocations on surface dynamics and morphological evolution. Here we investigate the near-equilibrium dynamics of surface-terminated dislocations using low-energy electron microscopy. We observe, in real time, the thermally driven nucleation and shape-preserving growth of spiral steps rotating at constant temperature-dependent angular velocities around cores of dislocations terminating on the (111) surface of TiN in the absence of applied external stress or net mass change. We attribute this phenomenon to point-defect migration from the bulk to the surface along dislocation lines. Our results demonstrate that dislocation-mediated surface roughening can occur even in the absence of deposition or evaporation, and provide fundamental insights into mechanisms controlling nanostructural stability. 相似文献
273.
Binding of tetracycline to mammalian spermatozoa 总被引:2,自引:0,他引:2
274.
J. R. Gillette J. V. Dingell F. Sulser R. Kuntzman B. B. Brodie 《Cellular and molecular life sciences : CMLS》1961,17(9):417-418
Zusammenfassung Nach Verabreichung von Imipramin (Tofranil) wurde aus dem Gehirn von Ratten Desmethylimipramin, das N-Monomethylderivat, isoliert. Dieser Metabolit beziehungsweise dessen Anreicherungin vivo scheint für die antidepressive Wirkung von Imipramin verantwortlich zu sein.
Presented in part as an abstract in Fed. Proc.20, 321 (1961). Some of the material in this communication is taken from a dissertation byJ. V. Dingell to be submitted to the Graduate School of Georgetown University in partial fulfillment of the requirements for the degree of Doctor of Philosophy. 相似文献
Presented in part as an abstract in Fed. Proc.20, 321 (1961). Some of the material in this communication is taken from a dissertation byJ. V. Dingell to be submitted to the Graduate School of Georgetown University in partial fulfillment of the requirements for the degree of Doctor of Philosophy. 相似文献
275.
Riassunto Viene descritta mediante riprese microcinematografiche a tempo in cellule del tumore di Walker trattate con desossiribonucleasi la formazione graduale di globuli conseguenti alla aggregazione di ribosomi. Si Riritiene pertanto che venga confermata l'ipotesi che nella cellular tumorale esista una condizione particolare per cui, ad una anormale produzione di ribonucleoproteine, non segua la produzione di concreti prodotti di sintesi. 相似文献
276.
277.
or fi y G1 , . 相似文献
278.
V Plouvier 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1978,286(4):359-362
125 species were investigated for rutinase. A high enzyme activity was found only in a few genera: Fagopyrum, Rhamnus, Berchemia, Sophora, Datisca and Danae. Lower activity was detected in several Lichens (Parmeliaceae) and diverse plants but is lacking in some specimens. In a number of species containing 3- or 7-rutinosides, no enzyme able to hydrolyse the latter seems to be present. 相似文献
279.
280.
T. B. G. Tilak V. Nagarajan P. G. Tulpule 《Cellular and molecular life sciences : CMLS》1976,32(9):1179-1180
Summary Male rats kept at a temperature of 4°–5°C were refractory to a lethal dose of aflatoxin compared to animals at 20°–21°C which exhibited a high mortality and marked liver damage. It is suggested that this decreased susceptibility is mediated through a stimulated microsomal drug-metabolizing system in cold environment. 相似文献