基于分层MANET的区域云数字图书馆研究

考虑到MANET网络充分的灵活性及高效能的优势,选取其作为云数字图书馆的服务网络：在云数字图书馆的相关理论研究基础上,提出了基于MANET的分层区域云数字图书馆模型,该模型包括了5层,MANET用户层,高速MAN网络层,门户网站层,虚拟数字图书馆接口层,云图书馆运行维护中心层。经过模拟实验,证明了该模型具有高效能,可靠性,安全性,能很好满足用户需求。     

塔里木河流域生态环境恶化的水文效应

塔里木河是我国最大的内陆河。 4条源流出山口多年平均天然径流量 2 2 4 .9× 10 8m3 (195 7～ 2 0 0 1年 )。在全球变暖的大背景下 ,塔里木河流域山区气候出现变暖增湿的趋势 ,2 0世纪 90年代径流量达 2 4 1.9× 10 8m3 ,增幅 7.6 %。由于源流区人类开发利用水资源的影响 ,使得补给塔里木河干流的水量不断减少 ,水文条件改变 ,造成干流上、中游段耗水严重 ,导致下游生态与环境急剧退化。自 2 0 0 0年以来 ,实施的从开都河—博斯腾湖向下游绿色走廊应急输水 ,已使下游生态环境开始恢复生机。     

A reactive pattern of ischemia-induced nestin protein in the rat brain

AIM:To explore the expressive profile of nestin protein in the focal ischemic brain and to study the recovery mechanism of brain focal infarct.METHODS:Cellular morphology,time-course and distribution pattern of nestin positive response were immunohistochemically examined in different brain regions of 36 adult male SD rats. RESULTS:Nestin positive response of different brain regions in sham operated rats was present in small- and micro-vasculartures and the third ventricle bottom and ependyma. A large number of nestin positive cells were detected in ischemic brain, and were more remarkable in the cortical areas of parietal lobe and preoptic area as well as ischemic caudoputamen. Stellate nestin positive cells were located in the deep layer of ischemic cortex, but fibrillary cells were located in the shallow layer. Nestin positive cells in the ischemic caudoputamen showed the same changes of morphology as those cells in the deep layer of ischemic cortex. Morphological and number alterations of nestin positive cells were the most remarkable at 1 weeks post-ischemia, which showed more hypertrophy and proliferation in morphology, and a marked increase in number was present in the ischemic cerebral cortex and the ischemic caudoputamen. These alterations of nestin positive cells persisted up to 6 weeks post-ischemia, and then, the nestin positive response in the ischemic brain decreased gradually.CONCLUSION:Focal cerebral ischemia induces nestin re-expression on reactive astrocytes, which may be very important to the self-recovery of cerebral infarct.     

丝兰属植物提取物降低鸡舍氨气浓度的效果试验

通过在21日龄的肉用仔鸡饲料中添加丝兰属植物提取物(其有效成分为丝兰皂角苷)，研究丝兰属植物提取物对降低鸡舍中氨气浓度和提高肉仔鸡生产性能的效果。试验结果表明，试验组鸡舍内氨气平均浓度为4．75mg／L，对照组鸡舍内氨气平均浓度为13．80mgl／L，试验组比对照组鸡舍内氨气平均浓度降低了9．05mg／L，经t检验，两鸡舍内氨气平均浓度差异显著(P＜0．05)，并且试验组比对照组饲料报酬提高了8.92％。     

Effect of atrial natriuretic peptide on acute lung injury induced by lipopolysaccharide

AIM: To investigate effect of atrial natriuretic peptide (ANP) on acute lung injury (ALI) induced by lipopolysaccharide (LPS) in rat. METHODS: Mean arterial blood pressure (MAP) was recorded with model 6280 physiology intelligentialize grapher, nitric oxide (NO) and endothelin (ET) concentrations in plasma were measured after lipopolysaccharide (LPS) or following LPS ,ANP was injected into vein in rats. After experiment,lung water as well as pulmonary histopathological changes was measured and observed, respectively. RESULTS: Administration of LPS elicited a persistence decrease in MAP (8.1 kPa±2.6 kPa,at 4 h,P<0.01 vs control); NO and ET concentration in plasma was evident higher than that in control group, respectively (P<0.01); Wet-dry ratio of lung was higher than that in control group (5.15±0.43,at 4 h) (P<0.05); Alveolus detelectasis was observed and pulmonary mesenchyme was thicker than that in control group. No erythrocyte and leukocytes in alveolus,which show an interstitial pulmonary edema, was observed in LPS+ANP group, ANP maintained MAP at higher levels (13.35 kPa±2.93 kPa, at 4 h, P<0.05 vs LPS) after an transient decline when LPS was injected; NO and ET concentration of plasma had all significantly decrease, respectively (P<0.05 vs LPS, at 4 h); Wet-dry ratio of lung was lower than LPS group (4.57±0.35, P<0.05). Compared with control group the ratio was not evident difference (P>0.05); The histopathological of lung displayed markedly improved. CONCLUSION: ANP attenuates ALI induced by LPS in the rat. The effect of ANP may be via decreasing secretion of ET,NO and regulation arterial blood pressure.     

水泡性口炎病毒人工感染小白鼠的组织学和免疫组织化学观察

水泡性口炎病毒（VSV）具有广泛的宿主范围，临床血清学调查发现，许多动物表现为血清阳性[1]，可以感染多种试验动物和禽类。感染动物大多数表现为阴性感染和持续性感染，本试验以小白鼠为攻毒对象，探讨VSV在体内的致病作用，进一步了解病毒在机体内的分布及其所引起的组织病理学变化。     

湖南猪致病性大肠杆菌的分离及药物敏感性监测

从湖南47个规模化猪场发生典型仔猪黄、白痢猪只的63份腹泻病猪分离出63株大肠杆菌，其中12株作致病力试验均有致病性，对25种抗菌药物药敏试验，大肠杆菌对胺卡那霉素和头孢唑啉敏感，敏感菌株分别占98．41％和92．06％；多种抗生素产生耐药性，且为多重耐药。     

opaR基因缺失对AHPND致病菌生物学特性及毒力质粒接合转移的影响

急性肝胰腺坏死病(acute hepatopancreatic necrosis disease, AHPND)严重影响了我国乃至全球对虾养殖业的发展。近期研究发现,致病菌毒力质粒携带trb型Ⅳ型分泌系统(type Ⅳ secretion system, T4SS)可在高菌体密度下介导毒力质粒发生接合转移,从而导致AHPND致病菌多样性。为探究群体感应与T4SS表达以及毒力质粒接合转移的关系,本研究以副溶血弧菌(Vibrio parahaemolyticus)群体感应系统的高密度调控子OpaR为研究对象,在致AHPND副溶血弧菌20130629002S01::cat(Vp2S01::cat)菌株基础上,利用同源重组技术构建opaR基因缺失株Vp2S01::catΔopaR。比较了出发菌株和缺失株在生长性能、运动性和生物被膜形成能力等方面的差异,分析了opaR基因对T4SS基因表达量以及质粒接合转移效率的影响。结果显示,opaR基因缺失不影响细菌的生长特性和群集运动,但泳动能力显著增加,生物被膜形成能力显著下降;接合转移实验显示,opaR基因缺失显著提高T4SS表达水平和接合转移效率。本研究为解析群体感应系统调控AHPND致病菌T4SS表达以及毒力质粒接合转移机制提供了基础数据,可为控制AHPND致病菌毒力质粒传播提供技术支撑。     

宁夏地区烟粉虱对5种常用杀虫剂的抗药性

采用浸叶法分别测定了宁夏8个地区烟粉虱成虫田间种群对4类5种杀虫剂的抗性.结果 表明,供试烟粉虱种群对高效氯氰菊酯已产生了中等至极高水平抗性,抗性倍数为33.31～227.98倍;对烯啶虫胺产生了中等至高水平抗性,抗性倍数为12.14～69.33倍;对毒死蜱和吡虫啉产生了低至中等水平抗性,抗性倍数分别为7.63～38....     

北京市八达岭林场不同林型林下可燃物调查分析

通过样地调查和样品处理,分析了八达岭林场3种林型林下各类可燃物的含水率及可燃物负荷量,得出结论:各林型中地被物层含水率最低,负荷量最大,是林下可燃物的主要组成部分;林下可燃物负荷量依次为:油松纯林＞油松阔叶混交林＞阔叶林,林下可燃物含水率为:阔叶林＞油松阔叶混交林＞油松纯林;油松林负荷量大,含水率小,又含有较多的油脂,具有较高的火险等级.对油松林提出了相应防火建议.