萃取浮选光度法测定微量钼的研究及应用

研究了用甲苯萃取浮选Mo(Ⅴ)—SCN~-—Kφ三元络合物的各种条件。在硫酸介质中,紫红色络合物最大吸收波长位于585nm,摩尔吸光系数为2.8×10~5l·mol~(-1)·cm~(-1),钼量在0—10μg/25ml范围内符合比耳定律。大量常见元素均不干扰,40倍的钨(Ⅵ)亦不干扰钼的测定,方法已应用于钨矿中微量钼的测定,其结果令人满意。     

长江中游平原地区黑杨派南方型无性系立地质量评价——Ⅰ.土壤-立地因子分析

影响黑杨派南方型无性系生长的综合土壤-立地因子有:有效水分、物理性状、通气条件和土壤养分.综合土壤-立地因子由反映立地质量的土壤-立地子因子构成.通径分析表明:影响土壤有效水分的土壤-立地子因子主要是局域位置、地形条件和地下水位;影响物理性状的是质地与结构;影响通气条件的是经营水平;而影响土壤养分的土壤-立地子因子是速效钾和pH值.     

Specific binding of antigenic peptides to cell-associated MHC class I molecules

T lymphocytes recognize antigen in the form of peptides that associate with specific alleles of class I or class II major histocompatibility (MHC) molecules. By contrast with the clear MHC allele-specific binding of peptides to purified class II molecules purified solubilized class I molecules either bind relatively poorly or show degenerate specificity. Using photo-affinity labelling, we demonstrate here the specific interaction of peptides with cell-associated MHC class I molecules and show that this involves metabolically active processes.     

新型延缓交联体系

用氧氯化锆和柠檬酸钠反应制得一种新型的延缓交联的交联剂──柠檬酸锆。用正交设计和粘度法得到了制备柠檬酸锆的最佳条件，即：氢氯化锆与柠檬酸钠的摩尔比为２：１．ｐＨ值为７．试验结果表明，柠檬酸锆可以延缓锆对聚丙烯酰胺、瓜尔胶、羟甲基瓜尔胶、羟乙基瓜尔胶、羟丙基瓜尔胶的交联速度。交联速度随聚合物浓度、柠檬酸锆对聚合物的质量比、温度、水的矿化度的增加而增加．柠檬酸锆对ＰＡＭ通过羧基交联，对瓜尔胶通过羟基交联。     

Characterization of the rough endoplasmic reticulum ribosome-binding activity.

The rough endoplasmic reticulum membranes of mammalian cells contain specific ribosome-binding sites. A purification to apparent homogeneity of a negatively charged protein (ERp180) of relative molecular mass 180,000 (180 K) was reported which was proposed to function as a rough endoplasmic reticulum ribosome receptor. We report here that ribosome-binding site activity quantitatively solubilized from rough endoplasmic reticulum membranes does not cofractionate with ERp180. By contrast, ribosome-binding site activity fractionates as a much smaller, positively charged protein.     

Genotoxic effects of dithane M-45 on the bone marrow cells of mice in vivo

Genotoxic effects of dithane M-45 were studied on the bone marrow cells of male albino mice (Lacca strain) in vivo. Different doses (30 mg, 40 mg and 300 mg/kg b.wt) of dithane M-45 were injected intraperitoneally and their effects were investigated after time intervals of 1, 2, 5 and 10 days. The chromosomal aberrations observed in the bone marrow cells of male mice after treatment with dithane M-45 were fragments, rings, dicentric chromosomes, terminal chromatid deletions, chromatid gaps and breaks. In addition to these chromosomal aberrations, physiological effects such as uneven stretching of chromatin material, end-to-end chromosomal associations, exchange configurations, clumping, stickiness and centromeric associations were also observed.     

秋水仙素诱导青虾次级卵母细胞二倍体初探

以青虾卵巢为材料，采用秋水仙素诱导多倍体次级卵母细胞．经滴片试验，确立此实验最佳滴片高度为1．5cm，通过设置5个秋水仙素浓度(0．08～0．40mg／mL)及3个作用时间(6～24h)，观察发生染色体加倍的细胞相对数目．实验结果表明：在使用秋水仙素的浓度为0．08～0．40mg／mL，处理6～24h时都可以获得多倍体卵细胞．在秋水仙素浓度是0．32mg／mL，处理6h可得到最高二倍体突变率(32．58％)．还测试了0．32mg／mL COM作用6h时ATPase活性与生理盐水对照组的变化，结果显示COM会在一定程度上影响细胞的新陈代谢．但是50％左右的成活率表明，这种诱导突变的方法仍具有一定的应用价值．     

KS-A型液体防冻剂在混凝土冬季施工中的应用

文章针对冬季施工中,混凝土防冻泵送剂需经常变换的缺点,提出了KS-A型液体防冻剂的优点,并从原材料、性能、操作关键、质量控制措施等方面进行论述,最后以施工实例进行佐证。     

ADO意义.NET在并发控制方面存在的问题及解决方案

针对ADO.NET在处理"丢失的修改"问题时,不支持"关键字和已修改字段"的并发控制问题提出了相应的解决办法;同时对ADO.NET架构本身带来的异常更新问题提供了解决思路.