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971.
Comparison of the localization of several muscle proteins in relaxed and contracted myofibrils. 总被引:1,自引:0,他引:1
The localization of several muscle proteins in relaxed and contracted myofibrils is compared. The morphology of the myofibrils and the behavior of these proteins was also investigated under extraction conditions. 相似文献
972.
973.
974.
Qiuli?Li Shuguang?LiEmail author Hongying?Zhou Huimin?Li Ji’an?Hong Qingchen?Wang H.?J.?Massonne 《科学通报(英文版)》2002,47(1):62-65
The U-Pb isotope compositions of rutile, omphacite and garnet in the eclogite from the Jinheqiao area in the Southern Dabie ultrahigh-pressure metamorphic zone were analyzed. The consistent high precision U-Pb age (218 ± 1.2) Ma of rutile in eclogite from the Dabie Mountains was obtained by two ways of isochron and common Pb correction based on the composition of omphacite. This proves that the omphacite in eclogite has a U/Pb ratio (m = 2.8) low enough to be used for common Pb correction in the analyses of rutile. Under the rapid cooling condition (40℃/Ma) the closure temperature for U-Pb diffusion in rutile is about 470℃. Thus, this U-Pb age of rutile proves that 218 Ma should be the cooling age of eclogite at 470℃ instead of the peak metamorphic age. 相似文献
975.
Calcineurin (CN) is thought to play a role in the synaptic plastivity and long-term potentiation (LTP) in the hippocampus.
Based on two LTP models in vivo, a specific inhibitor cyclosporin A (CsA) of CN was observed, which affected LTP in the hippocampal dentate gyrus of the
rats. The results indicated that CsA blocked LTP induced by high frequency stimulation (HFS) partly, but it had no effect
on the decrease of the onset and peak latency of population spikes (PS) except that it reduced the increase of the amplitude
after HFS. On the other hand, CsA blocked LTP induced by ginsenosides (GSS) completely. It suppressed the GSS-enhanced amplitude
of PS reversibly and blocked the decrease of the peak latency of PS induced by the GSS. These results suggest that the postsynaptic
CN plays a role in the induction of LTP in the hippocampus of the rats. 相似文献
976.
Zhuo?XuEmail author Shuguang?Zheng Zhenxing?Yue Yujun?Feng An?Jin Xi?Yao 《科学通报(英文版)》2002,47(6):513-518
The dielectric properties of Pb(Zn11/3Nb2/3)O3− BaTiO3−PbTiO3 relaxor ferroelectric ceramics near the rhombohedral and tetragonal phase boundary were investigated under hydrostatic pressure.
It was found that hydrostatic pressure made their phase transition temperature T
c and the peak temperature T
m decreased, and the frequency dispersion and relaxor behavior enhanced. In these disorder systems of composite pervoskite
structures, there appeared polar clusters or nanodomains. The unique physical characteristics, which made the relaxor behavior
enhanced, is that the correlation length among these nanodomains decreases greatly with the pressure increasing. 相似文献
977.
In eukaryotes, the ubiquitin-mediated protein degradation pathway has been shown to control several key biological processes such as cell division, development, metabolism and immune response. F-box proteins, as a part of SCF (Skp1-Cullin (or Cdc53)-F-box) complex, functioned by interacting with substrate proteins, leading to their subsequent degradation by the 26S proteasome. To date, several F-box proteins identified in Arabidopsis and Antirrhinum have been shown to play important roles in auxin signal transduction, floral organ formation, flowering and leaf senescence. Arabidopsis genome sequence analysis revealed that it encodes over 1000 predicted F-box proteins accounting for about 5% of total predicted proteins. These results indicate that the ubiquitin-mediated protein degradation involving the F-box proteins is an important mechanism controlling plant gene expression. Here, we review the known F-box proteins and their functionsin flowering plants. 相似文献
978.
Peat record reflecting Holocene climatic change in the Zoigê Plateau and AMS radiocarbon dating 总被引:2,自引:0,他引:2
Weijian?ZhouEmail author Xuefeng?Lu Zhengkun?Wu Lin?Deng A.?J.?T.?Jull D.?Donahue W.?Beck 《科学通报(英文版)》2002,47(1):66-70
Through the use of reliable AMS dating of high resolution (15–30 years) peat and the establishment of monsoon climate proxies
sequence, we have been able to recognize several cold, dry events in the Tibetan Plateau during the Holocene. The more obvious
ones occurred around 12800, 11300, 10200, 9580, 8900, 6400, 4400, 3700, 2800 and 1500 cal. aBP. These events correlate well
with both ice rafting events recorded in high latitude North Atlantic Ocean sediment cores and cooling events in the low latitude
SST. Spectral analysis indicates high frequency climate variation on centennial-millennial time scale during the Holocene.
This further reflects Holocene climate instability and the existence of centennial-millenium scale rhythm in mid latitude
areas as well. 相似文献
979.
坚毅 《上饶师范学院学报》2002,22(1):20-23
韩非的“矛盾”富言属于逻辑矛盾。他的“矛盾”思想则是非此即彼、非彼即此,二者必居其一。这种仅仅在对立两极中的思维方法并非完全正确。哲学上的辩证关系,借用“矛盾”、“对立”范畴来表述,也不十分恰当,因为矛与盾不是对立的双方,而辩证关系也应包括对立统一、鼎立统一、多立统一。所以我们必须确立立体矛盾观,即对立面-中介-对立面,或正中反矛盾论,或同异反分析法。 相似文献
980.