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21.
A. A. Lebedev A. M. Strel’chuk D. V. Davydov N. S. Savkina A. N. Kuznetsov L. M. Sorokin 《Technical Physics Letters》2002,28(9):792-794
The electrical characteristics of (p)3C-SiC-(n)6H-SiC epitaxial heterostructures obtained by sublimation epitaxy in vacuum are studied. The band discontinuities are determined and the energy band diagram of the heterojunction is constructed. It is shown that the obtained heterostructure offers a promising material for high electron mobility transistors. 相似文献
22.
C Lupu CA Goodwin AD Westmuckett JJ Emeis MF Scully VV Kakkar F Lupu 《Canadian Metallurgical Quarterly》1997,17(11):2964-2974
Tissue factor pathway inhibitor (TFPI), the main downregulator of the procoagulant activity of tissue factor.factor VIIa complex, locates in human endothelial cells (EC) in culture as well-defined clusters uniformly distributed both on the cell surface and intracellularly. We here demonstrate by immunofluorescence that TFPI colocalizes in EC with caveolin, urokinase-type plasminogen activator receptor, and glycosphingolipids. The localization of TFPI in caveolae in resting endothelium is proved by double immunogold electron microscopy for TFPI and caveolin. After ultracentrifugation of rat lung or EC homogenates through density gradients of Nycodenz, TFPI was highly enriched at densities of 1.05 to 1.08 g/mL, together with caveolin and alkaline phosphatase. By ELISA, more than half of the cellular TFPI was detected in Triton X-100-insoluble extracts of EC. TFPI incorporates [1-3H]ethanolamine and is cleaved from the cell surface by phosphatidylinositol-phospholipase C, indicating a specific glycosylphosphatidylinositol-anchorage mechanism for TFPI in the plasma membrane. Clustering of TFPI and its localization in caveolae are dependent on the presence of cholesterol in the membrane. Agonist-induced stimulation of EC caused marked changes of distribution for both TFPI and caveolin at subcellular level, with subsequent increase of the cell surface-associated inhibitory activity toward tissue factor.factor VIIa. Our findings suggest that, beside their function in transcytosis, potocytosis, cell surface proteolysis, and regulation of signal transduction, caveolae also play a direct role in the regulation of EC anticoagulant properties. 相似文献
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E. Ya. Davydov I. S. Gaponova T. V. Pokholok G. B. Pariiskii G. E. Zaikov 《应用聚合物科学杂志》2008,108(1):128-133
The features of initiation of free radical reactions in polymers by dimers of nitrogen dioxide are considered. The conversion of planar dimers into nitrosyl nitrate in the presence of amide groups of macromolecules has been revealed. Nitrosyl nitrate initiates radical reactions in oxidative primary process of electron transfer with formation of intermediate radical cations and nitric oxide. As a result of subsequent reactions, nitrogen‐containing radicals are produced. The dimer conversion has been exhibited by estimation of the oxyaminoxyl radical yield in characteristic reaction of p‐benzoquinone with nitrogen dioxide on addition of aromatic polyamide and polyvinylpyrrolidone to reacting system. The isomerization of planar dimers is efficient in their complexes with amide groups, as confirmed by ab initio calculations. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
26.
We have studied the effect of spontaneous polarization, which is inherent in noncubic silicon carbide (SiC) polytypes, on the characteristics of quantum wells (QWs) formed in the cubic region at the heterojunction. The analysis is performed for various QW models, including triangular, parabolic, and exponential. Conditions for the appearance of a two-dimensional electron gas at the interface are briefly discussed. 相似文献
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LV Osadchuk VV Gul'tiaeva AA Filimonenko L Jalkanen 《Canadian Metallurgical Quarterly》1996,82(5-6):102-108
15.7% of spermatozoa were found to be abnormal in silver fox males during their first reproductive season. The total number of spermatozoa and the abnormal spermatogenesis remained unchanged during mating season. Sexual stimulation increased the testosterone level only at the beginning of the mating season. 相似文献
30.
Beta-heterochromatin in Drosophila and the Syrian hamster share a similar DNA organization, few unique sequences, and scrambled repeats of mobile elements without tandem repetition. DNA in alpha-heterochromatin is tandemly repetitious, and we now show that the repeat unit can either contain or lack a mobile element. The tandem repeat organization of alpha-heterochromatin is presumably due to a concertina-like mechanism of unequal exchange between repeat units. Although both heterochromatin types are late replicating and can incorporate mobile retroposons, the sequence distinction between the two heterochromatins appears to be due to a property conferred by chiasmata upon the process of homologous recombination in beta-heterochromatin but not in alpha-heterochromatin. Chiasmata seem to suppress the concertina mechanism of unequal exchange and impart to beta-heterochromatin its nontandem, scrambled repeat organization. 相似文献