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排序方式: 共有300条查询结果,搜索用时 15 毫秒
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Monophenol oxidase (or tyrosinase-A(1)) activity appears to be absent from extracts from pupae of homozygous lozenge-glossy (lz(g)/lz(g)) females and (lz(g)/male symbol) males of Drosophila melanogaster. Diphenol oxidase (tyrosinase-A(2)) activity is less in the mutant extracts than in extracts of wild-type Oregon-R pupae of the same age and sex. 相似文献
294.
Transforming growth factor-beta (TGF-beta) signaling is mediated by a complex of type I (TBRI) and type II (TBRII) receptors. The type III receptor (TBRIII) lacks a recognizable signaling domain and has no clearly defined role in TGF-beta signaling. Cardiac endothelial cells that undergo epithelial-mesenchymal transformation express TBRIII, and here TBRIII-specific antisera were found to inhibit mesenchyme formation and migration in atrioventricular cushion explants. Misexpression of TBRIII in nontransforming ventricular endothelial cells conferred transformation in response to TGF-beta2. These results support a model where TBRIII localizes transformation in the heart and plays an essential, nonredundant role in TGF-beta signaling. 相似文献
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Barnett SJ 《Science (New York, N.Y.)》1909,30(769):413-414
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Donnelly JJ Barnett SW Dorenbaum A Stamatatos L 《Science (New York, N.Y.)》2002,297(5585):1277-8; author reply 1277-8
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The effect of eurasian snow cover on global climate 总被引:7,自引:0,他引:7
Numerical simulations with a global atmospheric circulation model suggest that largescale variations in the amount of snowfall over Eurasia in the springtime are linked to the subsequent strength of the Asian summer monsoon. Large-scale changes in Eurasian snow cover are coupled to larger scale changes in the global climate system. There is a large, strong teleconnection to the atmospheric field over North America. The model results also show snow cover effects to subsequently alter other climatic fields known to be intimately associated with the El Ni?o-Southern Oscillation (ENSO) phenomenon. Thus the model results seem to challenge the current dogma that the ENSO phenomenon is solely the result of close coupling between the atmosphere and ocean by suggesting that processes over continental land masses may also have to be considered. 相似文献
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Changes to foot-and-mouth disease (FMD) control policies since 2001 mean that emergency vaccination must be considered more readily as a control measure in the future. Since field application of vaccine for emergency use has only rarely been applied, the effectiveness of single dose administration, as a control measure in an outbreak situation, is poorly understood. In this review we consider all the available experimental data from studies utilizing either experimental or readily available, commercially produced vaccines, in order to assess their likely effectiveness as an additional means of controlling FMD transmission and spread in an emergency. Overall it is concluded that such vaccines offer an additional and valuable means of FMD control for both ruminants and pigs. They are able to reduce clinical disease, sub-clinical infection and excretion and onward transmission of virus. However, to be most effective, vaccination should be rapidly applied to give maximum opportunity for immunity to develop. We also identify areas for future research and emphasize the importance of vaccine efficacy studies in providing data for models that can help to predict the efficacy of differing FMD control strategies. 相似文献