A cohesive approach to thin-shell fracture and fragmentation

We develop a finite-element method for the simulation of dynamic fracture and fragmentation of thin-shells. The shell is spatially discretized with subdivision shell elements and the fracture along the element edges is modeled with a cohesive law. In order to follow the propagation and branching of cracks, subdivision shell elements are pre-fractured ab initio and the crack opening is constrained prior to crack nucleation. This approach allows for shell fracture in an in-plane tearing mode, a shearing mode, or a bending of hinge mode. The good performance of the method is demonstrated through the simulation of petalling failure experiments in aluminum plates. © 2005 Elsevier B.V. All rights reserved.

云南不同地区绵羊血液蛋白多态性研究

本研究采用平板式淀粉胶蛋白电泳技术对来自德钦县、巧家县、腾冲县的绵羊进行了 34个同功酶及血液蛋白的研究 ,共检测 36个遗传座位 ,其中有 8个座位显示多态 ,德钦绵羊多态百分率P =0 .194 4 ,平均杂合度H =0 .0 6 4 7,平均等位基因数A =1.2 2 2 2 ;昭通绵羊P =0 .2 2 2 2 ,H =0 .0 6 5 1;A =1.2 2 2 2 ;腾冲绵羊P =0 .16 6 7,H =0 .0 6 0 8;A =1.16 6 7。表明云南不同地区绵羊在蛋白水平上遗传多样性较为丰富。运用Phylip3.5软件包中的”GENETDIST”计算标准遗传距离 ,再结合以往研究的数据 ,运用该软件包中的”NEIGHBOR”和”UPGMA”法进行聚类分析 ,结果表明 ,云南绵羊起源于同一共同祖先 ,云南绵羊与印度绵羊、尼泊尔绵羊关系较近 ,而与西藏绵羊关系较远

GENETIC DIVERSITY IN THE CHINESE PANGOLIN (MANIS-PENTADACTYLA) INFERRED FROM PROTEIN ELECTROPHORESIS

We examined protein polymorphism of Chinese pangolins (Manis pentadactyla) from Yunnan Province of China, including two forms of three brown and nine dusky Chinese pangolins. Sixty-two genetic loci were screened; 12 loci were found to be polymorphic. The percentage of polymorphic loci (P) is 0.194, the mean individual heterozygosity (H) is 0.078, and the mean number of alleles (A) is 1.258. Furthermore, we calculated the genetic distance (D) between the two forms and found a low level of genetic divergence (D = 0.0206) between them, which indicates an almost-indistinguishable divergence at the level of proteins.

Xanthohumol, a novel anti-HIV-1 agent purified from Hops Humulus lupulus

Xanthohumol, prenylchacone flavonoid, is a natural product with multi-biofunctions purified from Hops Humulus lupulus. Its anti-HIV-1 activity was tested in the present study. Results showed that xanthohumol inhibited HIV-1 induced cytopathic effects, the production of viral p24 antigen and reverse transcriptase in C8166 lymphocytes at non-cytotoxic concentration. The EC50 values were 0.82, 1.28 and 0.50 mug/ml, respectively. The therapeutic index (TI) was about 10.8. Xanthohumol also inhibited HIV-1 replication in PBMC with EC50 value of 20.74 mug/ml. The activity of recombinant HIV-1 reverse transcriptase and the HIV-1 entry were not inhibited by xanthohumol. The results from this study suggested that xanthohumol is effective against HIV-1 and might serve as an interesting lead compound. It may represent a novel chemotherapeutic agent for HIV-1 infection. However, the mechanism of its anti-HIV-1 effect needs to be further clarified. (C) 2004 Elsevier B.V. All rights reserved.

Indian squid, Uroteuthis duvauceli, is an important commercial marine fauna in the coastal waters of Oman Sea

About 3600 specimens were collected by bottom trawl at 15 sampling stations. 24 biometric characters were measured for each specimens at the laboratory.. Microscopic cross – sections of statolith were used for age determination. Sex determination and fecundity were determined. Population dynamics parameters as well as stock as stock assessment including cohort analysis were estimated using FISAT software. The findings showed that Dorsal Mantle Length (DML) and Body weight (BW) of the Indian squid were 133.9 ± 0.78 mm and 99.61 ± 0.95 g respectively. Strong correlation was found between these 2 variables (R2 = 0.90). The maximum age was 5 years. Relationship between DML and age was highly significantly of p ≤ 0.05. Overall sex ratio (M: F = 0.52) was significantly different from the expected 1:1 ratio (p ≤ 0.05). The ovary weight and nidamental glands weight were 7.72 ± 0.0006 g and 3.07 ± 0.0003g respectively. Absolute and relative fecundity of the Indian squid were found to be 122733 ± 30.87 and 2348 ± 0.4 respectively. GSI were 14.35 in April and 8.63 in July. This squid is therefore a spring spawner. The infinite dorsal mantle length were 258.62 mm for females, 194.72 mm for males and 252.02 for both sexes respectively. For population growth and mortality parameters; K (0.65 per year for both sexes, 0.85 per year for males, 0.65 per year for females); t0 (0.24year for both sexes, 0.22 year in females, 0.26 year in male); φ` (2.30 in both sexes, 2.47 for males, 2.37 for females); Z (1.17 per year for both sexes, 1.10 per year in females, 1.39 per year, in males); M (0.70 per year for both sexes, 0.90 for males, 0.67 for females); F(0.27 per year for both sexes, 0.27 per year in males, 0.195 per year in females). Exploitation coefficient were 0.51 per year for both sexes, 0.57 per year males and 0.51 per year females respectively. The results indicates that since the Indian squid is a short live aquatic organism, therefore, the exploitation coefficient could be raised to 0.7 per year. The analysis showed that total biomass and MSY were 10103.5 ton and 2576.4 ton respectively. These findings are the first study of its sort about the Indian squid in the coastal waters of Oman Sea as well as North-West of Indian Ocean.

云南巨蜥类物种多样性及其生境、习性和现状的初步调查

调查表明在云南边境地区实际分布着3种巨蜥, 除V. salvator外, 尚有V. irrawadicus和V. vietnamensis。讨论了这3种巨蜥的有效性, 简要地报道了它们的生境、习性和生存现状, 并就保护问题提出参考意见。

广西河池地区鱼类资源调查及两支流的鱼类多样性比较

于1994年至2008年间,对广西河池地区的柳江水系和红水河水系进行了鱼类资源调查.依据实际调查,并结合以往文献记载,这两水系中分布的鱼类共有185种,分别隶属于9目21科107属.较以前调查,新增种类21种,包括1新属19新种.柳江水系分布的鱼类共有134种,分别隶属于8目19科88属.其中,鲤形目鱼类的种类最多,鲈形目鱼类次之,鲇形目鱼类第三,其他目的鱼类种类相对较少,仅1-3种.红水河水系分布的鱼类共有157种,分别隶属于8目20科101属.其中,鲤形目鱼类的种类最多,鲇形目鱼类次之,鲈形目鱼类第三.其他目的鱼类种类相对较少.红水河水系的鱼类多样性较柳江水系丰富,其主要原因为红水河流经区域喀斯特地貌发育,地下河流众多而且流域面积广,水量充沛.

NMDA受体NR1亚单位基因与精神分裂症的连锁分析

目的 了解N-甲基-D-天冬氨酸(NMDA)受体NR1亚单位基因与精神分裂症的连锁关系.方法 选取NR1亚单位基因所在区域的2个微卫星标记D9s1838和D9s1826,对94个符合美国精神障碍诊断与统计手册第4版精神分裂症诊断标准(DSM-Ⅳ)的中国汉族精神分裂症受累同胞对及家系成员共376个个体作基因分型,其中男性194名,女性182名.采用美国国立精神卫生研究所(NIMH)制订的《遗传研究诊断问卷》(DIGS),对家系成员躯体和精神状况进行评定;采用NIMH制订的《遗传研究家族问卷》(FIGS)了解家系结构.选用GENEHUNTER 2.1软件对分型资料进行非参数连锁分析.结果 两点、多点非参数分析最大LOD值均位于D9s1826,分别为1.70(P=0.050),2.08(P=0.015),两者均大于验证性连锁阈值1.2.结论 NR1基因区域微卫星标记与精神分裂症存在验证性连锁关系,提示NR1基因可能为精神分裂症的易感基因之一.

中鲤亚属的分支系统学分析

基于外部形态特征和内部骨骼特征对鲤科鲤属中鲤亚属进行了分支系统学分析。内群包括中鲤亚属的全部5种和鲤亚属的2种鱼类，外群采用乌原鲤。在鲤属鱼类和外群间共有48个性状存在变化。系统发育分析采用PAUP~(*)软件的Parsimony和Bootstrap两种方式的Branch-and-Bound算法。排除不能极化的特征和特有离征之后，还有28个特征可用，由这28个特征可得到唯一的系统树，树长69，一致性系数0.7246，排除无用特征的一致性系数0.6122，保留系数0.6346。由5种中鲤组成的中鲤亚属明显不构成一个单系群。结果表明：中鲤亚属是一个复系群，该类元应该被撤销。