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71.
72.
Summary Evidence is presented for the structures (II a), (II b) and (II c) for the bruceines A, B and C, the bitter principles isolated from the seeds ofBrucea amarissima.

18ème Communication sur les constituants amers des Simarubacées; 17ème Communication, voir2.  相似文献   
73.
Isocardenolides     
Zusammenfassung Ein einfacher Weg zur Synthese eines von zwei möglichen isomeren Cardenoliden wurde entwickelt und die Reaktionsfolge an Hand der Überführung von Pregnenolon in Isocardenolide V gezeigt.

Steroids and Related Natural Products XXI. For the previous contribution refer to:G. R. Pettit andP. Hofer, Helv. chim. Acta46, 2142 (1963).

A preliminary account of this study was presented (December 1963) at the VI. Pan-American Congress of Pharmacy and Biochemistry, Mexico City (Mexico).

This investigation was supported by PHS Research Grants CY-4074 (C3) to CA-04074-06 from the National Cancer Institute, Public Health Service.  相似文献   
74.
Résumé L'activité des cellules neurosécretrices dans le cerveau de la femelle deSarcophaga bullata est en corrélation avec le développement des larves dans la femelle et leur position.  相似文献   
75.
粗粒度并行遗传算法收敛性分析及优化运算   总被引:11,自引:0,他引:11  
提出了一种新型的粗粒度并行遗传算法(CGGA),该算法利用多个子种群基于不同的编码方式进行进化计算.首先各子群体独立进行交叉、变异和选择遗传操作,每代进化后迁移算子被引入用来进行种群问的信息交流,迁移算子将各个子种群的最优个体替换相邻种群最差个体后继续进化.基于时齐遍历马尔可夫链理论,给出了CGGA各个子种群的概率转移矩阵与其进化概率转移矩阵,证明了以概率1全局收敛.对典型的测试函数CGGA进行了求解.仿真结果表明,本算法的收敛性能优于经典遗传算法(CGA),可以有效解决CGA的过早收敛问题.  相似文献   
76.
在许多工业和环境应用中,不同时空尺度上的多孔介质中的多相渗流都是一个非常重要的过程。因此,了解确定微尺度上的多相渗流和其反应传递过程,并描述其宏观条件下的运动现象是很必要的。目前描述宏观下的多相渗流现象都是基于由达西定律经验公式得到的毛管压力一饱和度一相对渗透率关系式。然而,这些经验模型并不能完全反映实际的物理现象,尤其是大尺度和非均质介质中渗流问题。  相似文献   
77.
Postnatal neurogenesis in the guinea-pig   总被引:10,自引:0,他引:10  
J Altman  G D Das 《Nature》1967,214(5093):1098-1101
  相似文献   
78.
Objective: To evaluate effects of epigallocatechin-3-gallate (EGCG) on the viability, membrane properties, and zinc distribution, with and without the presence of Zn2+, in human prostate carcinoma LNCaP cells. Methods: We examined changes in cellular morphology and membrane fluidity of LNCaP cells, distribution of cellular zinc, and the incorporated portion of EGCG after treatments with EGCG, Zn2+, and EGCG+Zn2+. Results: We observed an alteration in cellular morphology and a decrease in membrane fluidity of LNCaP cells after treatment with EGCG or Zn2+. The proportion of EGCG incorporated into liposomes treated with the mixture of EGCG and Zn2+ at the ratio of 1:1 was 90.57%, which was significantly higher than that treated with EGCG alone (30.33%). Electron spin resonance (ESR) studies and determination of fatty acids showed that the effects of EGCG on the membrane fluidity of LNCaP were decreased by Zn2+. EGCG accelerated the accumulation of zinc in the mitochondria and cytosol as observed by atomic absorption spectrometer. Conclusion: These results show that EGCG interacted with cell membrane, decreased the membrane fluidity of LNCaP cells, and accelerated zinc accumulation in the mitochondria and cytosol, which could be the mechanism by which EGCG inhibits proliferation of LNCaP cells. In addition, high concentrations of Zn2+ could attenuate the actions elicited by EGCG.  相似文献   
79.
We carried out a genome-wide association study of type-2 diabetes (T2D) in individuals of South Asian ancestry. Our discovery set included 5,561 individuals with T2D (cases) and 14,458 controls drawn from studies in London, Pakistan and Singapore. We identified 20 independent SNPs associated with T2D at P < 10(-4) for testing in a replication sample of 13,170 cases and 25,398 controls, also all of South Asian ancestry. In the combined analysis, we identified common genetic variants at six loci (GRB14, ST6GAL1, VPS26A, HMG20A, AP3S2 and HNF4A) newly associated with T2D (P = 4.1 × 10(-8) to P = 1.9 × 10(-11)). SNPs at GRB14 were also associated with insulin sensitivity (P = 5.0 × 10(-4)), and SNPs at ST6GAL1 and HNF4A were also associated with pancreatic beta-cell function (P = 0.02 and P = 0.001, respectively). Our findings provide additional insight into mechanisms underlying T2D and show the potential for new discovery from genetic association studies in South Asians, a population with increased susceptibility to T2D.  相似文献   
80.
To identify genetic variants associated with head circumference in infancy, we performed a meta-analysis of seven genome-wide association studies (GWAS) (N = 10,768 individuals of European ancestry enrolled in pregnancy and/or birth cohorts) and followed up three lead signals in six replication studies (combined N = 19,089). rs7980687 on chromosome 12q24 (P = 8.1 × 10(-9)) and rs1042725 on chromosome 12q15 (P = 2.8 × 10(-10)) were robustly associated with head circumference in infancy. Although these loci have previously been associated with adult height, their effects on infant head circumference were largely independent of height (P = 3.8 × 10(-7) for rs7980687 and P = 1.3 × 10(-7) for rs1042725 after adjustment for infant height). A third signal, rs11655470 on chromosome 17q21, showed suggestive evidence of association with head circumference (P = 3.9 × 10(-6)). SNPs correlated to the 17q21 signal have shown genome-wide association with adult intracranial volume, Parkinson's disease and other neurodegenerative diseases, indicating that a common genetic variant in this region might link early brain growth with neurological disease in later life.  相似文献   
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