The choroid in the eye of the eel (Anguilla anguilla)

Summary By means of light and scanning electron microscopy evidence of the existence of a normally organized choroid in the eye of the eel,Anguilla anguilla, is presented.     

Effect of phthalic esters on lecithin cholesterol acyltransferase]

The in vitro effects of different esters of phthalic acid at increasing levels on the activity of LCAT have been studied using three currently known methods (Mickel and Foulds, Stokke and Norum, Alcindor). Inhibition from phthalates is high. It is proportional to the amounts used and in inverse ratio to the length of the carbon chains.     

植物系统分类学野外实习教学模式的探讨

植物学是一门实践性很强的学科,野外实习是学好植物系统分类学课程的最重要环节。文章分析了以往西藏大学理学院生物系学生植物学野外实习中存在的问题,探讨了野外实习改革的必要性,提出了野外实习改进模式和实施新思路,旨在提高学生专业基本技能,培养学生科学研究意识和素养。     

基于JIT的炼钢-连铸生产调度模型研究

在连铸工艺、设备资源等约束条件下,为提高炼钢-连铸生产效率,避免人工调度,炼钢-连铸作业的精准调度已成为钢铁行业迫切的需求.通过对某炼钢厂现场调研,整合流程信息和时间数据,基于JIT提炼出炼钢-连铸生产调度的核心问题--炉机节奏匹配;进一步构建起基于柔性 Jobshop的炼钢-连铸调度系统模型和数学模型以及基于最小松弛时间的调度规则;最后用Lekin仿真调度实例,并将仿真结果与实际生产调度数据进行了分析和比对.实验数据表明了模型的正确性.     

新型钢包的应力场及其影响因素模拟分析

以具有纳米绝热材料内衬的新型钢包为研究对象,通过建立三维有限元模型,运用ANSYS软件分析该种新型钢包与传统钢包在盛钢工况下的应力分布,并研究纳米绝热材料的导热系数、弹性模量、热膨胀系数对新型钢包应力场的影响。结果表明,盛钢工况下新型钢包的应力分布明显优于传统钢包,新型钢包包壳的最大应力比传统钢包包壳的最大应力减小22MPa;在一定范围内,新型钢包包壳的应力随纳米绝热材料导热系数和热膨胀系数的降低以及弹性模量的增大而逐渐减小。     

黑麦草幼苗在冻融及NaHCO_3复合胁迫下的生理响应

以冬牧70黑麦草幼苗为实验材料,考察黑麦草幼苗在单一人工模拟冻融胁迫(10,5,0,-5,0,5,10℃)及NaHCO_3复合胁迫下的生理响应机制.结果表明:在单一冻融胁迫下,黑麦草幼苗叶片中脯氨酸和丙二醛(MDA)的含量及过氧化氢酶(CAT)和超氧化物歧化酶(SOD)的活性均呈先升高后显著降低的变化趋势,过氧化物酶(POD)的活性呈先升高后缓慢降低的趋势;除CAT外,其他生理指标均在-5℃达到最大值,与其他温度下的活性相比存在显著性差异(P0.05);在复合胁迫处理条件下,生理指标呈"复合胁迫单一冻融胁迫对照"的规律;黑麦草幼苗叶片中蛋白质的质量比在0℃时达到最大值,复合胁迫和单一冻融组均高于对照组,即黑麦草幼苗在单一冻融胁迫及NaHCO_3复合胁迫下可快速提高抗氧化酶活性与渗透调节物质的质量比,以缓解胁迫导致的伤害,且复合胁迫对幼苗的影响更大.     

Immune control of an SIV challenge by a T-cell-based vaccine in rhesus monkeys

A recombinant adenovirus serotype 5 (rAd5) vector-based vaccine for HIV-1 has recently failed in a phase 2b efficacy study in humans. Consistent with these results, preclinical studies have demonstrated that rAd5 vectors expressing simian immunodeficiency virus (SIV) Gag failed to reduce peak or setpoint viral loads after SIV challenge of rhesus monkeys (Macaca mulatta) that lacked the protective MHC class I allele Mamu-A*01 (ref. 3). Here we show that an improved T-cell-based vaccine regimen using two serologically distinct adenovirus vectors afforded substantially improved protective efficacy in this challenge model. In particular, a heterologous rAd26 prime/rAd5 boost vaccine regimen expressing SIV Gag elicited cellular immune responses with augmented magnitude, breadth and polyfunctionality as compared with the homologous rAd5 regimen. After SIV(MAC251) challenge, monkeys vaccinated with the rAd26/rAd5 regimen showed a 1.4 log reduction of peak and a 2.4 log reduction of setpoint viral loads as well as decreased AIDS-related mortality as compared with control animals. These data demonstrate that durable partial immune control of a pathogenic SIV challenge for more than 500 days can be achieved by a T-cell-based vaccine in Mamu-A*01-negative rhesus monkeys in the absence of a homologous Env antigen. These findings have important implications for the development of next-generation T-cell-based vaccine candidates for HIV-1.     

支撑掩护式液压支架的优化设计

为了提高液压支架顶板管理以及承受较大载荷的能力,必须使液压支架顶梁前端的运动轨迹为水平摆幅最小的近似双扭线。通过对液压支架四连杆机构的运动特性分析,建立了四连杆机构的优化设计数学模型,基于遗传算法求出了使顶梁前端运动轨迹为近似双扭线,且双扭线水平摆幅e最小时的各杆长度及相应参数,并以ZY35型液压支架的设计为例进行了验证。结果表明:利用遗传算法对液压支架四连杆机构进行优化设计可以得到理想的设计参数,生产的液压支架工作状态平稳,支护效果良好。     

带钢表面缺陷图像的小波阈值降噪研究

以典型带钢表面缺陷图像为例,采用小波阈值降噪方法研究带钢表面缺陷图像的小波阈值降噪规律,并论述了带钢表面缺陷图像阈值的选择和小波基的选取.结果表明,图像经过小波变换后具有低熵性、多分辨率和选基灵活性等特点,使得小波阈值降噪提高了图像的信噪比、改善图像的质量,并且增强图像的清晰度.     

乙酰肝素酶(HPSE)与肿瘤生长、转移关系的研究进展

目的:通过文献学习,了解乙酰肝素酶与肿瘤的生长和转移的关系。结论:1.乙酰肝素酶的表达(heparananse HPSE)通过降解硫酸乙酰肝素细胞(heparansulfate,HS)和降解硫酸乙酰肝素蛋白聚糖(heparansulfate proteoglycan,HSPG),破坏、改变细胞外基质(extracellular matrix,ECM)和基底膜(basement membranes,BM)结构,促进肿瘤细胞侵袭、转移。2.诱导血管的生成直接作用于内皮细胞以生芽方式促进血管生成,通过释放肿瘤微环境和ECM中储存的高活性的HS-bFGF复合物来诱发直接的血管反应,促进肿瘤的生长。乙酰肝素酶的表达是判断多种肿瘤预后的标记物之一。