Deletion of stem-loop 3 is compensated by second-site mutations within the Gag protein of human immunodeficiency virus type 1

Encapsidation of human immunodeficiency virus type 1 (HIV-1) RNA involves specific interactions between viral Gag proteins and viral RNA elements located at the 5' untranslated region (UTR). These RNA elements are termed packaging (psi) or encapsidation (E) signals and mainly comprise the stem-loop 1 (SL1) and SL3 RNA structures. We have previously shown that deletion of the SL1 sequences is compensated by second-site mutations within Gag. Similar studies are now extended to SL3 and the results demonstrate that deletion of this RNA structure is rescued by two point mutations, i.e., A11V in p2 and I12V in nucleocapsid (NC). These two compensatory mutations are different from those associated with the rescue of SL1 deletion, suggesting that SL1 and SL3 may bind to different residues of Gag during viral RNA packaging. Analysis of virion-derived RNA in native agarose gels shows that deletion of SL3 leads to decreases in both viral RNA packaging and dimerization. These defects are corrected by the compensatory mutations A11V and I12V. Yet, defects in viral RNA dimerization at an early stage that were caused by the SL3 deletion in the context of a viral protease-negative mutation cannot be overcome by these two suppressor mutations. Therefore, the positive effects of A11V and I12V on dimerization of the SL3-deleted RNA must have taken place at the maturation stage.     

The study of tuberculosis outbreak in a high school—Shanghai,China, 2017–2018

Journal of Public Health - To investigate the attack rate of active tuberculosis (TB) cases and detection rate of latent tuberculosis infection (LTBI) cases, and to identify possible factors...     

Discrete choice experiment with duration versus time trade-off: a comparison of test–retest reliability of health utility elicitation approaches in SF-6Dv2 valuation

Quality of Life Research - To evaluate and compare the test–retest reliability of discrete choice experiments with duration (DCETTO) and time trade-off (TTO) in the Chinese SF-6Dv2 valuation...     

纳洛酮抢救海洛因中毒618例临床分析

目的：观察纳洛酮抢救海洛因中毒的疗效。方法：对618例海洛因中毒患,用纳洛酮抢救,首次剂量给纳洛酮针剂0．4－0．8mg静注,然后以0．4mg每5min1次,直到患清醒后再给0．8－1．2mg维持静滴。结果：618例中死亡9例,抢救成功率达98％。结论：纳洛酮是抢救海洛因中毒的理想特效药。     

恒河猴tPA基因的克隆、测序与真核表达

本试验采用高浓度乙二醇（EG-8）作为胚胎冷冻保护剂,以高浓度的半乳糖作为解冻稀释液,对MMTV-Wnt-1转基因小鼠的早期囊胚进行玻璃化冷冻保存。结果在EG-2中平衡4-6min和解冻时间为3-5min时获得了最佳冷冻效果。此条件下冷冻胚胎的总回收率为88.61%（109/123）;回收胚胎在体外发育率达88.99%（97/109）;孵化率达81.65%（89/109）;发育胚胎的移植出生率为38.36%（69/181）;冷漠胚胎移植出生后经PCR检测一半小鼠整合阳性。结果表明使用高浓度的乙二醇作为冷冻保护剂和以高浓度的半乳糖作为冻稀释液能有效地保存转基因小鼠胚胎。     

社区精神分裂症综合式家庭干预对照研究

目的：了解综合式家庭干预对社区精神分裂症患者和家属的效果。方法：在宝山区随机抽取186例精神分裂症进行一年的综合式家庭干预对照研究,干预组86例接受综合式家庭干预和常规社区服务,对照组100例仅接受常规社区服务。结果：干预组患者年复发率下降47．3％,社区功能明显改善,干预组家庭对有关疾病知识增长,心理状况改善,照料负担减轻,与对照组比较效果显著。结论：综合式家庭干预对精神分裂症患者家属有良好的效果,应纳入常规社区服务。     

高血压病以昼夜血压模式指导治疗初探

目的：探讨高血压以昼夜血压模式指导药物治疗的疗效。方法：124例高血压患者被随机分为两组：观察组80例,采用以昼夜血压模式为依据,指导选用药物进行治疗,着重加强异常升高血压部份的降压治疗,同时加强血压监测;对照组仍按照常规方法治疗,6周为1疗程,治疗前和治疗后都检测血压和24小时动态血压。结果：观察组降压的总有效率和昼夜血压模式转为正常杓形态明显高于对照组,结论：高血压病患者以昼夜血压模式为依据指导用药降压治疗有较好的医疗效果。     

Kubelka-Munk模型下的兔血管对氦-氖激光的散射与吸收特性

测量了兔动脉和静脉对 He-Ne激光的反射和透射传输特性。实验采用两积分球系统及波长为632.8nm的He-Ne激光器,并根据测量数据及采用 Kubelka-Munk模型分析和计算了兔动脉和静脉组织对该长激光的吸收系数、散射系数及总的光强I（x）及前向散射通量i(x）和后向散射通量j(x）随厚度的变化情况。结果表明,兔动脉和静脉的漫反射率和透射率有明显差别,而且,动脉对激光的吸收系数明显较静脉的要小,而动脉对激光的散射系数却明显较静脉的要大,在动脉和静脉组织中总的光强I（x）及前向散射通量i(x）和后向散射通量j(x）随组织厚度的变化情况也有明显的区别。     

低铅染毒大鼠体内脂质过氧化及抗氧化水平改变

目的：观察低剂量铅染毒后大鼠体内脂质过氧化水平改变,为铅的毒作用机制研究提供依据。方法：以醋酸铅为受试物,雄性Wistar大鼠为受试对象,分别观察其脏器脂质过氧化水平改变。结果：低铅染毒后,大鼠各脏器超氧化物歧化酶（SOD）、谷胱苷肽过氧化物酶（GSH－Px）及过氧化脂质（LPO）均有不同程度改变（P＜0.05,P＜0.01）,而巯基（－SH）含量仅肝脏变化较明显。结论：较低剂量的铅即可引起体内脂质过氧化水平的改变,而这种变化可能是铅的毒作用途径之一。     

现场总线控制网络中OPC服务器的设计与应用

介绍了OPC（OLF for Process Control)技术及其在现场总线中的应用模式。给出OPC服务器的设计与实现的一种方法,并讨论了客户程序通过OPC服务器与现场设备的交互过程及OPC技术对现场总线的巨大影响。