动态毛吸法测定纤维表面能

本文用浸润测定仪对玻璃纤维和Kevlar-49芳纶纤维进行了表面能测定,讨论了纤维束柱末端沾湿量的影响,提出了浸润仪测试数据的正确处理方法,求得了Kevlar-49纤维的表面能并对其色散分量和非色散分量进行了解析.     

工业CT技术在无损检测炸药部件中的应用综述

综述了美国能源部的有关单位将工业ＣＴ技术用于高能炸药无损检测的研究状况，劳伦斯利弗莫尔国家实验室（ＬＬＮＬ）洛斯阿拉莫斯国家实验室（ＬＡＮＬ）和潘台克斯工厂（ＰａｎｔｅｘＰｌａｎｔ）在这方面做的大量工作，包括ＣＴ机的建造，实验方法的制定和图像的重建等。测试样品有ＰＢＸ－９５０２，ＰＢＸ－９５０１和ＬＸ－１０－２炸药的药饼和半球，对ＣＴ技术在无损检测高能炸药方面的实用性和优越性作了评价。     

Temperature-regulated expression of the tac/lacl system for overproduction of a fungal xylanase in Escherichia coli

Temperature-regulated expression of recombinant proteins in the tac promoter (Ptac) system was investigated. Expression levels of fungal xylanase and cellulase from N. patriciarum in E. coli strains containing the natural lacI gene under the control of the Ptac markedly increased with increasing cultivation temperature in the absence of a chemical inducer. The specific activities (units per milligram protein of crude enzyme) of the fungal xylanase and cellulase produced from recombinant E. coli strain pop2136 grown at 42 degrees C were about 4.5 times higher than those of the cells grown at 23 degrees C and were even slightly higher when compared with cells grown in the presence of the inducer isopropyl beta-D-thiogalactopyranoside. The xylanase expression level in the temperature-regulated Ptac system was about 35% of total cellular protein. However, this system can not be applied to E. coli strains containing lacIq, which confers over production of the lac repressor, for high-level expression of recombinant proteins. In comparison with the lambda PL system, the Ptac-based xylanase plasmid in E. coli pop2136 gave a considerably higher specific activity of the xylanase than did the best lambda PL-based construct using the same thermal induction procedure. The high-level expression of the xylanase using the temperature-regulated Ptac system was also obtained in 10-litre fermentation studies using a fed-batch process. These results unambiguously demonstrated that the temperature-modulated Ptac system can be used for overproduction of some non-toxic recombinant proteins.     

The X-linked lymphoproliferative-disease gene product SAP regulates signals induced through the co-receptor SLAM

In addition to triggering the activation of B- or T-cell antigen receptors, the binding of a ligand to its receptor at the cell surface can sometimes determine the physiological outcome of interactions between antigen-presenting cells, T and B lymphocytes. The protein SLAM (also known as CDw150), which is present on the surface of B and T cells, forms such a receptor-ligand pair as it is a self-ligand. We now show that a T-cell-specific, SLAM-associated protein (SAP), which contains an SH2 domain and a short tall, acts as an inhibitor by blocking recruitment of the SH2-domain-containing signal-transduction molecule SHP-2 to a docking site in the SLAM cytoplasmic region. The gene encoding SAP maps to the same area of the X chromosome as the locus for X-linked lymphoproliferative disease (XLP) and we found mutations in the SAP gene in three XLP patients. Absence of the inhibitor SAP in XLP patients affects T/B-cell interactions induced by SLAM, leading to an inability to control B-cell proliferation caused by Epstein-Barr virus infections.     

天津市正常人全血和血清微量元素含量分析

人体内微量元素含量平衡与否与人体健康状态有着密切关系已为大量实践所证实。人体血液中微量元素的正常值测定是研究人体健康与微量元素关系的一项基础性工作,本文提供了天津市正常人全血及血清中几种微量元素含量的数据。     

Molecular mechanisms of transforming growth factor-beta signaling

The present experiments examined the effects of posttraining intrahippocampal injections of the degradative enzyme-resistant methylcarbamyl analog of the bioactive phospholipid platelet-activating factor (mc-PAF) and the platelet-activating factor (PAF) receptor antagonists BN52021 and BN 50730 on memory in male Long-Evans rats trained in a hidden platform version of the Morris water maze. Following an eight-trial training session, rats received a unilateral intrahippocampal injection of mc-PAF (0.5, 1.0, or 2.0 microgram/0.5 microliter), lyso-PAF (1.0 microgram/0.5 microliter), the cell surface PAF receptor antagonist BN 52021 (0.25, 0.5, or 1.0 micrigram/0.5 microliter/, the intracellular PAF receptor antagonist BN 50730 (2.0, 5.0, or 10.0 microgram/0.5 microliter), or vehicle (50% DMSO in 0.9% saline; 0.5 microliter). On a retention test conducted 24 h after training, the escape latencies of rats administered mc-PAF (1.0 or 2.0 microgram) were significantly lower than those of the vehicle-injected controls, demonstrating a memory-enhancing effect of mc-PAF. Injections of lyso-PAF, a structurally similar metabolite of PAF, had no influence on memory, indicating that the memory-enhancing effect of mc-PAF is not caused by membrane perturbation by the phospholipid. The retention test escape latencies of rats administered BN 52021 (0.5 microgram) and BN 50730 (5.0 or 10 microgram) were significantly higher than those of the controls, indicating a memory impairing effect of both PAF antagonists. When mc-PAF, BN 52021, or BN 50730 was administered 2 h posttraining, no effect on retention was observed, indicating a time-dependent effect of the neuroactive substances on memory storage. The findings suggest a role for endogenous PAF in hippocampal-dependent memory processes.     

面向对象工程数据库管理系统O2S并发事务模型

Ｏ２Ｓ是我们在ＳＵＮ工作站上开发的一面向对象工程数据库管理。本文针对工程应用域事务的嵌套性，长时性，数据库逻辑分区性和涉及数据量大的四个显著特点，阐述了Ｓ２Ｓ的事务管理模型。对工程域事务的管理，数据库的恢复和封锁技术进行了讨论。     

溜槽与溜槽驱动装置的联接方式及溜槽的更换

介绍了国内外布料溜槽与其传动装置的几种联接方式及更换溜槽的过程与工具；分析了这几种联接方式各自的优缺点及包钢在这方面所做的工作。