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101.
核电站蒸汽发生器出现故障的几率较高。为减少蒸汽发生的质量和体积 ,提出用降压闪蒸的方法来产生蒸汽以替代蒸汽发生器。结合 10 MW核供热堆海水淡化系统 ,分析了闪蒸器蒸汽发生系统的特点。改进设计后 ,闪蒸器的体积比蒸发器小 4 0 % ,质量小约 80 % ;使用闪蒸器旁路调节对改善运行特性起很大作用。该设计拟用于摩洛哥核能海水淡化示范系统中。 相似文献
102.
Muhammad Mehmood Shahi Ahmad H. Ismail Ali MA. Abdul Amir AL-Mokaram R. Vikneswaran Sohail Ahm Amir Hamz Arshid Numan 《自然科学进展(英文版)》2017,27(5):582-587
Nitrogen-doped reduced graphene oxide(NrGO)sheets decorated with Co(OH)_2nanoflakes were prepared by a single-step hydrothermal process.The morphological and structural characterizations of as synthesized Nr GO@Co(OH)_2nanoflakes were performed by field emission scanning electron microscopy(FESEM),EDX-mapping and X-ray diffraction(XRD).Nr GO@Co(OH)_2nanoflakes modified glassy carbon electrode(GCE)was used for electrochemical sensing of dopamine in neutral medium.The nanocomposite modified electrode showed enhanced electrochemical sensing ability for the detection of dopamine and the limit of detection(Lo D)was found to be 0.201μM with a sensitivity value of 0.0286±0.002 m A m M~(-1).Interference studies revealed that Nr GO@Co(OH)_2─GCE endow excellent selectivity for DA detection even in the presence of higher concentration of common co-existing physiological interfering analytes.Additionally,proposed sensor demonstrated excellent performance in urine samples with promising reproducibility and stability. 相似文献
103.
104.
Heat shock protein gene expression during Xenopus development 总被引:2,自引:0,他引:2
J. J. Heikkila N. Ohan Y. Tam A. Ali 《Cellular and molecular life sciences : CMLS》1997,53(1):114-121
Stress-induced heat shock protein gene expression is developmentally regulated during early embryogen esis of the frog, Xenopus laevis. For example, a number of heat shock protein genes, such as hsp70,
hsp90, and ubiquitin are not heat-inducible until after the midblastula stage of embryogenesis. Furthermore, the family of small heat shock protein
genes, hsp30, are differentially expressed after the midblastula stage as well as being regulated at the level of mRNA stability. Many
of these stress proteins are also synthesized constitutively during oogenesis and embryogenesis during which they may act
as molecular chaperones as well as being involved in sequestering proteins in an inactive state until required by the developing
embryo. Furthermore the induction of these stress protein genes has been correlated with enhanced thermoresistance. During
stressful conditions heat shock proteins probably prevent aggregation or misfolding of damaged protei
ns within the embryo. 相似文献
105.
Stimulation of bovine adrenal chromaffin cells results in a rise in the concentration of cytosolic calcium which triggers the release of catecholamines by exocytosis. Several cytosolic proteins that bind to secretory granule membranes in a calcium-dependent manner have been implicated in exocytosis and some belong to a family of calcium-binding proteins, the annexins. One of these, calpactin, is a tetramer consisting of two heavy and two light chains (relative molecular masses 36,000 and 10,000 respectively) and can aggregate and fuse membranes in vitro in the presence of arachidonic acid. Calpactin is found at the cell periphery and is phosphorylated when chromaffin cells are stimulated. We show here that both calpactin and calpactin heavy chain (p36) reconstitute secretion in permeabilized chromaffin cells in which secretion has been reduced as a result of leakage of cellular components. This effect is inhibited by an affinity-purified antibody against p36. Secretion from permeabilized cells is inhibited by a synthetic annexin-consensus peptide, but not by a nonspecific hydrophobic peptide; this inhibition is reversed by p36. Our results indicate that either calpactin or p36 is essential for exocytosis. 相似文献
106.
107.
Ferrari MJ Grais RF Bharti N Conlan AJ Bjørnstad ON Wolfson LJ Guerin PJ Djibo A Grenfell BT 《Nature》2008,451(7179):679-684
Although vaccination has almost eliminated measles in parts of the world, the disease remains a major killer in some high birth rate countries of the Sahel. On the basis of measles dynamics for industrialized countries, high birth rate regions should experience regular annual epidemics. Here, however, we show that measles epidemics in Niger are highly episodic, particularly in the capital Niamey. Models demonstrate that this variability arises from powerful seasonality in transmission-generating high amplitude epidemics-within the chaotic domain of deterministic dynamics. In practice, this leads to frequent stochastic fadeouts, interspersed with irregular, large epidemics. A metapopulation model illustrates how increased vaccine coverage, but still below the local elimination threshold, could lead to increasingly variable major outbreaks in highly seasonally forced contexts. Such erratic dynamics emphasize the importance both of control strategies that address build-up of susceptible individuals and efforts to mitigate the impact of large outbreaks when they occur. 相似文献
108.
Summary UV-irradiation of phenylalanine by 253.7 nm light in the presence of hydrogen peroxide formed 5 ninhydrin reactive products and ammonia. Four of them were identified as aspartic acid, serine, alanine and lysine.Acknowledgments. This work was supported by the Council of Scientific and Industrial Research. Thanks are due to the Head of the Department for facilities and to. Mr.Rakesh C. Sharma for help. 相似文献
109.
N. M. Ali 《Cellular and molecular life sciences : CMLS》1984,40(2):197-198
Summary Experimental infection byDiplostomum phoxini of the brain of laboratory hatched and rearedPhoxinus phoxinus induces the migration along the Xth cranial nerve of periodic acid Schiff positive granular leucocytes (PAS-GLs). These differentiate and grow into cells that lie between the parasite and the neurones of the host. The transformed cells are associated with elevated levels of heparin and serotonin in the brain; little histamine was detected. The reactive cell is identified as a mast cell.This work was carried out with M.R.L. Johnston's guidance. Teresa Townshend is thanked for assistance with techniques to hatch and raiseP. phoxinus. 相似文献
110.