254 resultados para 191-1179B


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壤白蚁属 Parahypotermes Zhu et Huang, 新属模式种: 曼允壤白蚁Parahy potermes manyunensis, 新种. 属征: 兵蚁头近卵圆形, 头背面被毛稀少, 两侧缘于触角前骤然狭缩, 头中部最宽, 后缘宽圆, 头背面中部明显隆起; 左上颚内缘中部第1缘齿上方具2—3枚小齿. 比较与讨论: 本新属与地白蚁属 Hypotermes Holmgren 较接近. 但 Hypotermes 头两侧缘触角前不呈狭缩状; 左上颚第1缘齿上方不具锯齿状小齿; 头背面中部呈弧状隆起。

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Repeated daily treatment with the catecholamine-depleting agent, reserpine, dramatically reduced performance on the delayed response task, a test of spatial working memory that depends upon the integrity of the prefrontal cortex. Delayed response performance fell from an average of 27.2/30 trials correct before reserpine treatment to an average of 20.4/30 trials correct after repeated reserpine administration. Injection of the alpha2-adrenergic agonist, clonidine (0.0001-0.05 mg/kg), to chronic reserpine-treated monkeys significantly restored performance on the delayed response task; performance after an optimal dose averaged 27.8/30 trials correct. Clonidine's beneficial effects on delayed response performance were longlasting; monkeys remained improved for more than 24 h after a single clonidine injection. The finding that clonidine is efficacious in reserpinized animals supports the hypothesis that alpha2-adrenergic agonists improve cognitive function through actions at postsynaptic, alpha2-adrenergic receptors on non-adrenergic cells. In contrast to the delayed response task, reserpine had little effect on performance of a visual discrimination task, a reference memory task which does not depend on the prefrontal cortex. These results emphasize the importance of postsynaptic alpha2-adrenergic mechanisms in the regulation of working memory,

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The southeastern region of Yunnan province is a key site for drug trafficking and HIV-1 infection spread from the west of Yunnan and Laos to southeastern China. To investigate the prevalence of HIV-1 infection and hepatitis C virus (HCV) coinfection among injection drug users (IDUs) in southeastern Yunnan, three cohorts of 285 addicts, including 242 IDUs and 43 oral drug users, living in the cities of Gejiu and Kaiyuan and the county of Yanshan were studied. HIV-1 and HCV infections were detected by enzyme-linked immunosorbent assay and/or polymerase chain reaction. Data on the age, sex, risk behavior, drug use history, employment, ethnic background, and marriage status were obtained by interview. The overall prevalence of HIV-1 infection was 71.9%. The rate of HCV coinfection among 138 HIV-1-infected IDUs was 99.3%. Most HIV-infected IDUs were 20 to 35 years old (86.7%) and were ethnic Han (75.9%), suggesting that the epidemic in Yunnan is no longer confined to non-Han ethnic minorities, HIV prevalence in female IDUs (81.2%) was significantly higher than in male IDUs (68.2%) (p <.05). The prevalence of HIV infection reached 68.4% after 1 year of injection drug use. Needle/syringe sharing is the major high risk factor for the spread of HIV-1 and HCV infections. Large-scale educational campaigns are urgently needed to reduce the spread of HIV and HCV infection in these regions.

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目的研究废旧变压器拆解点周围妇女儿童多氯联苯(PCBs)暴露水平及危险性评价。方法以F地区为研究现场,选择该地区中心小学50名8~10岁学龄儿童和其母亲为研究对象,采集妇女儿童空腹外周静脉血,用Agilent 5973N GC-MSD超痕量分析方法检测其PCBs(13个异构体)含量及血液、尿液临床生化检验,并作调查问卷及健康体检,最后作危险度评价。结果妇女和儿童外周静脉血中多氯联苯几何均值分别达175.9 ng/g、191.6 ng/g类脂;健康体检,儿童龋齿率82%。结论该地区妇女儿童血液中的PCBs含

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本研究利用淡水鲫鱼肝脏为主要原材料提取乙酰胆碱酯酶(acetylcholinesterase,AChE),并设计正交试验确定了鲫鱼肝脏中乙酰胆碱酯酶的最佳提取条件:通过酶抑制法衡量敌敌畏、辛硫磷、三唑磷、乐果等四种不同种类有机磷农药对粗酶液的抑制作用;将鱼肝和鱼脑中乙酰胆碱酯酶活性及蛋白含量的进行对比研究。研究结果表明:提取液pH值、提取液种类以及原料与提取液的质量体积比对酶液的活性影响显著;被测四种有机磷农药中,敌敌畏对AChE活性抑制作用最强。鱼脑的AChE比酶活是肝脏的AChE比酶活的3~7倍。

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长江江豚,即江豚扬子亚种,是仅分布于长江及附属湖泊中的唯一江豚淡水亚种,也是3个江豚亚种中最濒危的一个亚种。本文概述了30年来国内外关于长江江豚繁殖生物学方面的研究成果,主要从繁殖生态学、组织解剖学、生理学以及行为学等4个方面阐述了长江江豚繁殖生物学研究现状,并对其中一些相互矛盾和有争议的问题进行了分析。探讨了今后研究中应注意的重点问题,力图为长江江豚的繁殖生物学研究指明方向,为早日实现长江江豚的人工繁殖奠定基础。