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排序方式: 共有10000条查询结果,搜索用时 31 毫秒
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Edwin Y.B.Pun 《复旦学报(自然科学版)》2007,(5)
1 Results Rare earth doped waveguide amplifiers and devices have been demonstrated in silica, crystal and other glass hosts. These rare earth doped optical waveguide devices are based on inorganic materials. Many processing steps are required and can lead to long fabrication time and low yield.Polymer materials offer many distinct properties compared to inorganic materials, such as ease of fabrication, low production costs, simple processing steps, and compatibility with micro-fabrication technologies. ... 相似文献
74.
tRNase Z: the end is not in sight 总被引:1,自引:0,他引:1
Although the enzyme tRNase Z has only recently been isolated, a plethora of data has already been acquired concerning the
enzyme. tRNase Z is the endonuclease that catalyzes the removal of the tRNA 3′ trailer, yielding the mature tRNA 3′ end ready
for CCA addition and aminoacylation. Another substrate cleaved by tRNase Z is the small chromogenic phosphodiester bis(p-nitrophenyl)phosphate (bpNPP), which is the smallest tRNase Z substrate known so far. Hitherto the biological function as
tRNA 3′-end processing enzyme has been shown only in one prokaryotic and one eukaryotic organism, respectively. This review
summarizes the present information concerning the two tRNase Z substrates pre-tRNA and bpNPP, as well as the metal requirements
of tRNase Z enzymes.
Received 29 March 2007; received after revision 15 May 2007; accepted 21 May 2007 相似文献
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Dhar-Chowdhury P Malester B Rajacic P Coetzee WA 《Cellular and molecular life sciences : CMLS》2007,64(23):3069-3083
Glycolysis is an evolutionary conserved metabolic pathway that provides small amounts of energy in the form of ATP when compared
to other pathways such as oxidative phosphorylation or fatty acid oxidation. The ATP levels inside metabolically active cells
are not constant and the local ATP level will depend on the site of production as well as the respective rates of ATP production,
diffusion and consumption. Membrane ion transporters (pumps, exchangers and channels) are located at sites distal to the major
sources of ATP formation (the mitochondria). We review evidence that the glycolytic complex is associated with membranes;
both at the plasmalemma and with membranes of the endo/sarcoplasmic reticular network. We examine the evidence for the concept
that many of the ion transporters are regulated preferentially by the glycolytic process. These include the Na+/K+-ATPase, the H+-ATPase, various types of Ca2+-ATPases, the Na+/H+ exchanger, the ATP-sensitive K+ channel, cation channels, Na+ channels, Ca2+ channels and other channels involved in intracellular Ca2+ homeostasis. Regulation of these pumps, exchangers and ion channels by the glycolytic process has important consequences
in a variety of physiological and pathophysiological processes, and a better understanding of this mode of regulation may
have important consequences for developing future strategies in combating disease and developing novel therapeutic approaches.
Received 20 July 2007; received after revision 30 July 2007; accepted 17 August 2007 相似文献
77.
1 Results In addition to single wall and multiwall carbon nanotubes[1], several structures,which are more or less related to fullerenes,including carbon nanohorns[2a], carbon nanospheres[2b] and onion like carbon structures[2c] have been reported.A new simple straight forward method to access some of these structures is the solid-state pyrolysis of different organometallic complexes in a sealed vessel,which led so far to carbon nanotubes[3a,b], carbon nanocables[3c] and onions[3d]. 相似文献
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