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231.
几种含二茂铁基染料的合成 总被引:2,自引:1,他引:1
设计合成了5个含二茂铁基的萘酰亚胺类、蒽醌类、偶氮类染料,通过核磁共振氢谱、质谱、元素分析对其结构进行了表征,并对合成进行了讨论。 相似文献
232.
233.
为探讨表没食子儿茶素没食子酸棕榈酸酯(EGCG-P)抗丙型肝炎病毒(HCV)的作用,本研究采用cck-8法检测EGCG-P对Huh7.5.1细胞系的毒性作用,丙型肝炎病毒核酸定量检测试剂盒检测HCV滴度,通过实时荧光定量PCR(RT-PCR)选择合适的病毒感染复数(MOI),进而研究药物抗病毒的作用效果。结果:EGCG-P浓度为0~50mg/L时对Huh7.5.1细胞无毒害作用,且抗病毒作用显著;当其浓度为25mg/L时病毒表达量为阳性对照的1/6,可见EGCG-P能高效抑制HCV的增殖。 相似文献
234.
We find ourselves at the dawning of a new millennium, uneasy denizens of a world of growing flux. The models of reality on which we rely in our continuing effort to master the turbulent and hypercompetitive marketplace are failing us. Even the much touted 20th-century innovation referred to by Peter Senge in his 1990 bestseller of the same name as the fifth discipline, that is, systems thinking, turns out to be less than adequate to the task. Therein lies the central purpose of this paper: to demonstrate why there's nothing wrong with systems thinking that a little chaos can't remedy. My intent is twofold: first, to expose the problematic partialness of this paradigm, given its tendency to direct one's focus to not to the whole system, but to its exterior half, and, second, to introduce the reader to Chaos, the powerful cosmology now emerging from 20th-century science, as a science of whole wholes—one that enables the practitioner of management and systems sciences to comprehend the system's externality, its subtle within, and most importantly, the crucial relationship between them. 相似文献
235.
利用光学金相显微镜观察比较了18MnHP冷轧板的原始坯料及在系列退火温度下的铁素体晶粒度。对其晶粒超细进引了分析研究,考虑了冷形变量、退火工艺和原始晶粒对成品材晶粒度的影响;结果表明,板坯厚度所决定的冷轧变形量是主要因素。并就钢板出现10级超细晶未对制瓶冲压产生不利影响作了报道 相似文献
236.
Han X 《Cellular and molecular life sciences : CMLS》2004,61(15):1896-1906
The critical roles of apolipoprotein E (apoE) in regulating plasma lipid and lipoprotein levels have been
extensively studied for over 2 decades. However, an understanding of the roles of apoE in the central nervous
system (CNS) is less certain. This review will summarize the available experimental results on the role of apoE
in CNS lipid homeostasis with respect to its modulation of sulfatide trafficking, alteration of CNS cholesterol
homeostasis and apoE-induced changes in phospholipid molecular species in specialized subcellular membrane
fractions. The results indicate that apoE mediates sulfatide trafficking and metabolism in the CNS. Moreover,
although apoE does not affect the cholesterol mass content or the phospholipid mass levels and composition in the
CNS as a whole, apoE modulates cholesterol and phospholipid homeostasis in selective subcellular membrane
compartments. Through elucidating the roles of apoE in CNS lipid metabolism, new insights into overall functions
of apoE in neurobiology can be accrued ultimately, leading to an increased understanding of CNS lipid metabolism
and the identification of novel therapeutic targets for CNS diseases.Received 9 January 2004; received after revision 28 February 2004; accepted 10 March 2004 相似文献
237.
YUXuping ZHUJunli YAOXunping HEShicheng HUANGHaining CHENWeiliang LIDebao 《科学通报(英文版)》2004,49(13):1370-1375
To understand the antagonistic mechanism of the broad spectrum antagonistic Enterobacter cloacae B8,Tn5 transposon-mediated mutagenesis is performed using suicide plasmid pZJ25. Two mutant strains that lost antagonistic character are isolated. Tagging with kanr gene on Tn5,an antagonistic related DNA fragment, the F fragment, right of the Tn5 insertion site is cloned in a plasmid named pTLF,from one of the mutant strains B8F. The 733 bp F fragment is then sequenced after subcloning. Genomic DNA of the original B8 strain is isolated, digested with Pst I and ligated to Pst I cassette. DNA fragments left and right of the F fragment are amplified from the Pst I cassette library using cassette primer and specific primers designed according to known sequence. 1106 bp sequence left of the F fragment and 664bp sequence right of the F fragment are finally obtained. Bioinformatics analysis shows that the contig assembled from the sequences of the cloned antagonistic related DNA fragments of B8 encodes three ORFs and is homogeneous to admM,admN and admO genes of Pantoea agglomerans andrimid biosynthetic gene cluster (AY192157). The ORF, named anrF gene which encodes a polyketide synthase, knocked out by Tn5 insertion, is a homology of admM and the insertion site of Tn5 is at 214 bp upstream of the stop codon. It is concluded that the anrF gene is a gene related to the antagonistic activity of E. cloacae B8, and speculated that the antagonistic substance produced by B8 is an andrimid. 相似文献
238.
方自虎 《湘潭大学自然科学学报》2005,27(4):114-120
提出了一个简单的混凝土三维本构模型,基于塑性流动理论,混凝土的非线性受压特性通过屈服条件、流动和硬化规则描述.编制了钢筋混凝土结构非线性分析8节点和20节点的三维等参单元程序.程序中钢筋分别采用分离与分布模式模拟.通过三个经典的算例对比分析,表明了提出的混凝土本构模型能够有效地模拟结构的破坏荷载和破坏全过程. 相似文献
239.
合成了新配合物Cu(teta)(PF6)2(teta=内消旋5,7,7,12,14,14-六甲基-1,4,8,11-四氮杂环十四烷),并且经元素分析、红外光谱和电子吸收光谱表征,其结构通过单晶X-射线衍射法确定.该配合物属单斜晶系,空间群P21/n.晶胞参数α=0.8465(5),b=0.9093(6),C=1.6418(11)(nm),β=97.227(10),V=1.2537(14)nm3,Z=2,Pcak=1.690g/cm3,F(000)=654.00.最后的偏差因子R1=0.097,WR2:0.190[1>2σ(I)].铜原子位于配合物的对称中心,与teta的四个氮原子呈平面正方形配位. 相似文献
240.
英语专业八级测试中的阅读部分因难度高、题量大而成为影响考生八级通过率的重要因素之一。英语阅读的解题能力由英语阅读水平决定,而英语阅读水平则取决于英语理解知识、理解技能及图式结构。八级阅读的制约因素在于六级以上的词汇量、高层次的阅读策略及背景知识的广泛程度。针对学生现状与八级阅读要求的差距,只有既进行强化答题能力训练,又抓好系统化的全面拓展阅读能力培养,才能真正促进教学、提高八级通过率。 相似文献