Abnormal expression of centrosome protein (centrin) in spermatozoa of male human infertility

To study the relations between male infertility and centrosome protein (centrin) and the functions of centrin in spermatogenesis, the matured spermatozoa of 10 normal male people and 18 male infertility patients were stained by immunofluorescence labeling antibody against centrin. The results showed that two fluorescence signal dots appeared in the normal male spermatozoa and were located at the base of flagellum. They are proximal centriole and distal centriole. However, in some spermatozoa of the male infertility, centrin protein was located abnormally at the base of flagellum and its staining signals were spread, the normal proximal and distal centrioles were confused and could not be recognized separately. These results suggest that abnormality of centrosome protein may be related to male infertility. This discovery may be used as a marker of abnormal sperm and male infertility.     

Two closely linked rice U14 boxC/D snoRNAs

By analysis of the conserved elements in yeast U14 boxC/D snoRNA. the conserved elements in rice U14 boxC/D snoRNA have been speculated. Through computer search of the international rice genome database, two rice U14 snoRNA gene candidates are obtained. These two putative U14 snoRNA genes are closely linked on rice chromosome 2. The coding sequences of these two snoR-NAs exhibit the hallmark structure of boxC/D antisense snoRNA. They both have conserved boxC and boxD sequences and a 14nt-long complement to the sequence between 414nt and 427nt of rice 18S rRNA (according to GenBank accession no. X00755). The experimental evidence shows that these two snoRNAs are involved in the methylation of the complementary sequence of rice 18S rRNA. The existence and localization of these two snoRNAs are proved by RT-PCR and Northern blot. Further analysis shows that both of the newly found rice snoRNAs have high homology with maize U14 snoRNA. and they are named rice U14.1 snoRNA and U14.2 snoRNA respectively. The gene sequence encoding these two snoRNAs has been deposited in the GenBank database under accession number of AF332622.     

Geochemistry and petrogenesis of Jurassic high Sr/low Y granitoids in eastern China: Constrains on crustal thickness

The Jurassic high Sr/low Y granitoids in eastern China are characterized by high Sr/Y (27—166) and La/Yb (14—66) ratios, low abundance in Y (6—21 μg/g) and Yb (0.5—2.0 μg/g), comparable with those of adakites defined by Defant et al. Thus, they were recently considered as adakitic rocks by some researchers. Compared with the typical adakites in circum-Pacific margins, however, these high Sr/low Y granitoids have higher K₂O (-3.5%) but lower Al₂O₃ (-16.0%) as well as lower Mg^# (-38) and δ Sr_N (-1.23) values. Furthermore, they show relatively flat HREE patterns with Y/Yb values of -10 close to the chondritic value. These geochemical characteristics indicate a residue mineral assemblage of hornblende, garnet and plagioclase for these high Sr/low Y granitoids melt. Thus, they were generated by partial melting at 9—13 kbar (30—45 km in depth), similar to the Archaean high-Al TTG rather than the modern adakites. Generation of these high Sr/low Y granitoids cannot be considered as evidence for a thickened crust (>50 km) and/or the presence of the “Eastern China Plateau” in Jurassic.     

用弯曲应变能方法评价沥青混合料的低温抗裂性能

通过对沥青混合料低温开裂机理的分析和对大量试验结果的总结，以弯曲应能密度临界值为指标来评价沥青混合料的低温抗裂性能，首先，分析了沥青混合料低温开裂机理，其次，在MTS810材料试验系统上进行了0℃下的沥青混合料的低温弯曲试验；最后，用灰关联的方法分析了沥青混合料的弯拉强度、临界弯拉应变、油石质量比，表观密度及所用沥青的针入度等指标对混合料的应变能密度临界值的影响程度，研究表明，一般情况下，沥青混合料储存的弹性应变能越多，沥青混合料的低温抗裂性能就越好，由于沥青混合料的应变能密度临界值指标是混合料临界弯拉应变和弯拉强度2个指标的综合，用它来评价沥青混合料的低温抗裂性能更加科学；低温时沥青混合料的允许变形能力较差，提高混合料的允许变形能力可明显增强沥青路面的低温抗裂性能。     

正丁胺自盐酸溶液中在铝表面上的吸附及其缓蚀作用

本文用失重法研究了在1M盐酸溶液中正丁胺对铝的缓蚀作用,应用吸附理论和Sekine方法处理实验数据,探讨了正丁胺在铝表面上的吸附行为以及吸附与缓蚀作用之间的关系,估算了正丁胺吸附的热力学参数.     

TBQ-1型总日射表倾斜效应理论初探

本文研究了TBQ-1型总日射表的倾斜效应,给出了实验测量的总日射表在各种倾角和不同方位时的倾斜效应。并根据此表的结构,从感应面的热平衡出发,对其各类传热方式随倾角的改变进行理论分析,得到了表内对流换热的改变是倾斜效应的主要原因的结论。最后提出改进总日射表结构以减少倾斜效应的建议。     

树状电力网络潮流问题的一个有效算法

本文介绍一种适合于树状电力网络潮流问题研究的有效算法——Dist Flow法。计算结果表明,它具有计算速度快,收敛步数少,收敛精度高等优点。对严重病态的系统仍能确保收敛。     

负载敏感液压系统的稳定性分析

分别对负载敏感泵和负载敏感系统提出了数学模型和动态特性,通过数字仿真及实验分析研究,确定了泵及系统稳定工作的参数范围。理论和实验表明,负载敏感泵应用于本系统中很容易引起不稳定现象,解决的最简单办法是选取适当的阻尼。     

从古代东西方两种数学思想体系看当代软件开发方法中的两派之争

本文叙述了古代东西方两种数学思想体系的异同,特别分析了东方数学思想体系的直观性和实用性等特点,并指出了这两种数学思想体系与当代软件开发方法中的形式化方法和非形式化方法的两派之争之间的密切联系。     

胎球蛋白—胶体金探针的制备

本文用柠檬酸钠还原法制备胶体金，以光吸收法和琼脂糖电泳法检测胎球蛋白－胶体金探针的稳定性，为胶体金探针的制备探索最佳条件。实验结果表明：ｐＨ在２～３．５时，探针稳定性较差；ｐＨ在５～１０时，需要较少量胎球蛋白即可获得稳定探针，在电场中也可稳定存在，ｐＨ在６～１０之间探针的电泳行为相似。实验表明，琼脂糖电泳有可望成为鉴定和分离胶体金探针的简易途径。