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1.
目的以图像分析法检测海马脑片NMDA损伤后透光性变化,并评价NMDA受体拮抗剂氯胺酮的保护作用。方法大鼠海马脑片在35℃以100μmol/LNMDA处理10min后再灌注60min,诱导透光度改变,并用TTC染色、病理切片加以验证损伤作用。结果NMDA处理大鼠海马脑片后,其透光度先迅速升高,再灌注后降低到正常水平以下;氯胺酮(10、100μmol/L)能够明显抑制透光度的双向改变;TTC染色和病理切片结果与透光法相符。结论本文建立了适宜的海马脑片NMDA损伤模型,透光法可用于评价NMDA损伤及保护药物的作用。 相似文献
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《大众科技》2020,(1)
目的:探讨中药复方益肺温阳化浊汤对Aβ诱导的AD大鼠模型海马Aβ异常沉积与神经元凋亡的关系及Caspase-9、Caspase-3、Bcl-2、Bax凋亡相关因子的影响。方法:采用MorriS水迷宫测试各组大鼠行为学,流式细胞仪检测神经细胞凋亡率,Western Blot检测各组Caspase-9、Caspase-3、Bcl-2、Bax的表达;观察益肺温阳化浊汤低、中、高剂量对Aβ诱导的AD大鼠海马区Aβ含量及凋亡因子的影响。结果:模型大鼠经益肺温阳化浊汤处理后,海马区Aβ含量明显降低,神经元凋亡减轻,抑制Caspase-9、Caspase-3、Bax表达,上调抗凋亡蛋白Bcl-2的表达,并呈一定的剂量依赖性。结论:益肺温阳化浊汤可能通过促进Aβ诱导的AD大鼠海马区神经细胞中Aβ的清除,减轻Aβ的神经毒性,从而抑制神经元的凋亡,起到保护神经元的作用。 相似文献
3.
目的 设计气 液交界式浴槽,并用于探讨海马脑片H2O2损伤的机制.方法 气 液交界式浴槽包括内室和外室.内室的主要结构为嵌入体,用于放置海马脑片.外室的主要作用是为海马脑片提供足够的氧气.另外用生化、形态学、电生理的方法来验证浴槽的可行性.最后观察H2O2对海马脑片群峰电位的影响.结果 浴槽能够长时间(1～8h)的维持海马脑片活性.H2O2能够浓度依赖性损伤海马脑片,同时NMDA受体阻断剂氯胺酮对H2O2诱导的海马脑片损伤具有明显的保护作用.结论 浴槽可以适用于生化和形态学以及电生理等研究,并发现海马脑片H2O2损伤至少部分是通过NMDA受体发挥作用的. 相似文献
4.
目的在开放式压力控制培养系统作用下体外培养大鼠视网膜神经细胞（retinal neurons,RNs）,观察米诺环素对其活性及凋亡的影响．并进—步探讨其对受损RNs保护的可能机制．方法采用出生0-3d的Sprague Dawlev（SD）大鼠视网膜神经细胞体外混合培养。制备RNs加压培养模型．通过细胞形态学观察,四唑盐（MTT）比色法测定细胞活力,吖啶橙／溴化乙锭（AO／EB）染色法检测细胞的凋亡率来观察米诺环素对上述损伤细胞的保护及治疗作用．以及应用免疫细胞化学染色法。观察诱导型一氧化氮台酶（iNOS}和半胱天冬酶-3,（caspase-3）表达的改变、结果 加压培养后,在倒置显微镜下RNs与对照组相比形态改变较咀.细胞活力降低,大量细胞发生凋亡（占53.93％）.而米诺环素治疗组（20μmol／L）细胞则形态改善．活力显著增高：凋亡数目减少（占17．29％）．差异具有显著性（P〈0.0051）。免疫细胞化学染色法示米诺环素治疗组细胞内NOS和caspase-3表达较加压损伤组减少。结论 一定剂量的米潜环素在体外可有效抑制蓝力。引起的大鼠视网膜神经细胞损伤及凋亡。抑制NOS和capase-3的表达可能是其潜在作用机制。 相似文献
5.
睾丸间质细胞胰岛素样生长因子－Ⅰ基因表达的调控 总被引：1，自引：0，他引：1
评估了联岛素样生长因子－Ⅰ（ＩＧＦ－Ｉ）ｍＲＮＡ在大鼠睾丸Ｌｅｙｄｉｇ细胞中的基因表达。用１５％～６０％Ｐｅｒｃｏｌｌ液密度梯度离心，可将原始的间质细胞分成不同的３条带。ＩＧＦＩ．ｍＲＮＡ主要位于Ｌｅｙｄｉｇ细胞丰富组分（带３），带１和带２组分仅含少量ＩＧＦ－ＩｍＲＮＡ．Ｌｅｙｄｉｇ细胞ｍＲＮＡ具有碱基从０．８～７．５ｋｂ的多种型，在２５～５５日龄大鼠中均存在ＩＧＦ－ＩｍＲＮＡ。用Ｋｌｉｎｅｆｅｌｔｅｒ等方法高度纯化Ｌｅｙｅｉｇ细胞，发现大多数ＩＧＦ－ＩｍＲＮＡ位于这些Ｌｅｙｄｉｇ细胞，而在整个睾丸组织或其它间质细胞检测不到ＩＧＦ－ＩｍＲＮＡ。大鼠应用生长激素（ＧＨ）后，Ｌｅｙｄｉｇ细胞中ＩＧＦ－ＩｍＲＮＡ增加２倍以上，提示Ｌｅｙｄｉｇ细胞中的ＩＧＦ－ＩｍＲＮＡ亦依赖ＧＨ．Ｌｅｙｄｉｇ细胞产生的间质ＩＧＦ－Ｉ在睾丸中可能具有自分泌和旁分泌作用。 相似文献
6.
睾丸间质细胞胰岛素样生长因子—Ⅰ：基因表达的调控 总被引：1，自引：0，他引：1
评估了胰岛素样生长因子－Ｉ（ＩＧＦ－Ｉ）ｍＲＮＡ在大鼠睾丸Ｌｅｙｄｉｎｇ细胞中的基因表达，用１５％－６０％Ｐｅｒｃｏｌｌ液密度梯度离心，可将原始的间质细胞分成不同的３条带。ＩＧＦＩ．ｍＲＮＡ主要位于Ｌｅｙｄｉｎｇ细胞丰富组分（带３），带１和带２组分仅含少量ＩＧＦ－１ｍＲＮＡ．Ｌｅｙｄｉｎ细胞ｍＲＮＡ具有碱基从０．８－７．５ｋｂ的多种型，在２５－５５日龄大鼠中均存在ＩＧＦ－ＩｍＲＮＡ，用Ｋｌｉｎｅｆ 相似文献
7.
对自然数k≤n－１，F（n，k）定义为：存在长为F（n，k）的由１，２，…，组成的数列Sn，k使对每个k，１≤i≤k，Sn，k的前F（n，i）项以１，２，…，n的全部i－排列为其子排列且任何长小于F（n，k）的数列不满足这一条件，对此：１９８２年，CaiMaocheng犤１犦证明了F（n，k）≤k（n－１）＋１－犤k４犦。１９８９年，单?犤２犦证明了F（n，k）≤k（n－１）＋１－犤k＋２６犦－犤k６犦。１９９２年，徐士达犤３犦证明了F（n，k）≤k（n－１）＋１－犤k＋２６犦－犤k６犦－犤k－２６犦。同时猜想：F（n，k）＝k（n－１）＋１－犤k＋２… 相似文献
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9.
一氧化氮合酶抑制剂对大鼠缺氧缺血性脑损伤神经元凋亡的影响 总被引：1，自引：0，他引：1
目的研究神经元凋亡在大鼠缺氧缺血性脑损伤（HIBD）中的地位及作用。并探讨选择性一氧化氮合酶抑制剂-7-硝基-吲唑（7-NI）对大鼠HIBD时神经元凋亡的影响。方法24h时用HE染色、TUNEL法、透射电镜观察和检测神经元凋亡并评估7-NI对神经元凋亡的影响。结果HIBD后24h在海马、皮质等处检测到神经元凋亡。7-NI使海马及皮质部位的神经元凋亡数显著降低。结论神经元凋亡参与了HIBD后神经元迟发性死亡。7NI有显著的抗HIBD后神经元凋亡的作用。 相似文献
10.
摘要：本文探讨了变革型领导行为对员工创新产生影响的作用机制，即变革型领导是否通过领导－下属关系的中介作用对员工创新产生影响。采用结构方程模型的方法分析了变革型领导行为、领导－下属关系以及员工创新之间的关系。对西安一高新企业的领导和下属，以及苏州EMBA学员及其下属进行问卷调查,共收回183对匹配的有效问卷。研究结果发现：（1）变革型领导与员工创新、领导－下属关系的紧密性和朋友互助维度分别显著相关，而与情感关系维度相关性不显著；（2）领导－下属关系的紧密性和朋友互助维度与员工创新显著相关，情感关系与创新相关性不显著；（3）朋友互助维度对变革型领导与员工创新起到完全中介作用。 相似文献
11.
A research group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol-a chemical found in the skins of red grapes in red wine-can improve the sensitivity of mice to the hormone insulin according to a report in the October issue of Cell Metabolism.…… 《中国科学院院刊(英文版)》2008,22(1):14-15
Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said. 相似文献
12.
《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
13.
Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
14.
《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
15.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
16.
Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
17.
Active biological molecules functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery disease diagnosis therapy new nanodevice construction.…… 《中国科学院院刊(英文版)》2008,22(1):22-22
Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction. 相似文献
18.
Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
19.
Leah A. Lievrouw 《The Information Society》2000,16(2):155-159
This essay focuses on universal service and the Internet as means to support social and political participation. The emphasis on access to telecommunications systems in conventional approaches to universal service is contrasted with access to content. A model of the information environment is described that accounts for the roles of content and conduit, both of which are necessary conditions to achieve true access. A method is outlined for employing information indicators to observe or measure the information environment. 相似文献
20.
Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献