微波对绞股蓝皂甙提取率的影响

绞股蓝（Fiveleaf Gynostemma Herb）主要有效成分为绞股蓝皂甙,绞股蓝皂甙的化学成分均为四环三萜达玛烷型结构,具有多种药用功能,是一种十分优良的功能性食品原料。本文研究了微波对绞股蓝皂甙提取率的影响。结果表明,绞股蓝皂甙提取率在采用微波助提时比直接水提法有明显的提高,其最佳工艺条件为：微波功率350W,辅助提取时间10min;水浴提取时间90min,水浴提取温度80℃,料液比1：30,溶液pH10。     

鸭公树子化学成分预试验研究

目的：采用系统预试法对鸭公树子可能含有的化学成分进行分析研究,初步探索鸭公树子中所含的化学成分。方法：采用经典的化学反应鉴别法,以鸭公树子的水提取液、乙醇提取液和石油醚提取液进行研究,结合多种指示剂和显色剂,观察反应结是否沉淀或者颜色反应。结果：鸭公树子中含有多肽类、蛋白质类、多糖类、生物碱类、黄酮类、甾体类、皂苷类、内酯类、三萜类、有机酸、挥发油及油脂类等成分。结论：初步确定鸭公树子含有的多种化学成分,为鸭公树子药材资源的进一步开发和利用提供基础。     

三七提取液中三七皂苷R1近红外在线检测方法构建

目的:建立测定三七总皂苷提取液中三七皂苷R1含量的近红外光谱快速分析方法,实现三七提取过程质量的稳定监控.方法:以HPLC法测定值作为参比,采用近红外透射光谱法,结合一阶导数(FD)预处理方法建立三七提取过程三七皂苷R1含量的质控指标的快速定量分析模型.结果:三七提取液三七皂苷R1校正模型的校正集的相关系数R2C= 99.41,预测集的相关系数RV=99.94,预测均方差和交叉验证均方差分别为0.0493和0.0871.结论:近红外光谱分析技术可作为一种三七提取过程三七皂苷R1含量的在线分析方法.     

棉子糖提取精制工艺的研究

利用棉籽粕为原料提取棉子糖,乙醇提取法溶剂消耗量大、提取液中棉酚含量多、存在安全隐患,水提取法提取液中含有大量的杂糖、蛋白以及盐类。发酵法和酶解法在棉子糖的精制工艺中研究较少。本文利用水提法提取棉子糖,发酵法除杂糖,酶解法除蛋白,串联离子交换树脂脱色脱盐的方法最终得到高纯度棉子糖产品。对比传统的棉子糖提取纯化工艺,这种方法得到的棉子糖收率和纯度均较高,且不使用有机溶剂,用来制备棉子糖是可行的。     

壮瑶药剑叶耳草的化学成分预实验

目的:采用系统预实验法对广西民间常用壮瑶药剑叶耳草的化学成分进行预实验,对其化学成分进行初步研究。方法:采取试管法、纸斑法,分别对剑叶耳草全草的水、95%乙醇、石油醚提取液进行研究,通过多种化学试剂的显色反应或沉淀反应,对其可能含有的化学成分进行检测。结果:剑叶耳草全草中可能含有的化学成分有糖类、多糖类、苷类、皂苷类、黄酮类、蒽醌类、香豆素类、酚类、有机酸类、植物甾醇类、三萜类和油脂类等。结论:初步确定剑叶耳草化学成分种类丰富,为其进一步开发利用提供实验依据和参考。     

藏药囊距翠雀化学成分预试验

目的对藏药囊距翠雀可能含有的化学成分进行定性分析。方法采用化学反应鉴别方法,通过多种指示剂和显色剂的沉淀、颜色等反应,对囊距翠雀水提取液、乙醇提取液、酸水提取液和石油醚提取液进行试验。结果藏药囊距翠雀中可能含有的蛋白质、多肽或氨基酸、糖类、多糖和苷类、鞣质、有机酸、黄酮、酚类、甾体类、生物碱和挥发油等成分。结论初步确定囊距翠雀可能含有的化学成分,为进一步研究其化学成分和生物活性提供实验依据。     

西洋参中总皂苷的提取工艺研究

目的:优选西洋参中总皂苷的最佳醇提工艺。方法:采用紫外分光光度法,以人参总皂苷含量为指标,采用L9(34)正交试验设计,考察提取溶媒体积,提取次数,提取溶媒用量对人参总皂苷提取率的影响,优选最佳提取工艺条件。结果:提取工艺条件:采用8倍量的70%乙醇,回流提取2次,每次3h,西洋参总皂苷含量为5.23%。结论:优选工艺可较好的提取西洋参中的人参总皂苷。     

民族药石笔木叶化学成分预实验

目的:采用系统预实验法初步探索石笔木叶的化学成分,为系统开发民族药石笔木叶有效成分提供科学参考。方法:采用显色反应、沉淀反应或层析对石笔木叶水、95%乙醇和石油醚提取预试液进行定性检识,通过实验结果初步判断石笔木叶中可能含有的化学成分。结果:石笔木叶中可能含有氨基酸、蛋白质类、还原糖、多糖、苷类、皂苷类、有机酸类、酚类、鞣质类、甾体、三萜类化合物、黄酮类、内酯类、香豆素及其苷类、蒽醌类、挥发油、油脂类等化合物。结论:初步确定了石笔木叶含有的化学成分,为进一步分离鉴定该药用植物生物活性成分及系统开发提供了实验参考依据。     

壮药三叶香茶菜乙酸乙酯部位化学成分预试验研究

目的:通过系统预法对壮药三叶香茶菜乙酸乙酯部位浸膏中可能含有的化学成分进行预实验,初步探索三叶香茶菜乙酸乙酯部位浸膏的化学成分。方法:三叶香茶菜乙酸乙酯部位浸膏用水、乙醇和石油醚提取,取滤液进行研究,通过多种指示剂和显色剂的颜色或沉淀反应,对三叶香茶菜乙酸乙酯部位浸膏可能含有的化学成分进行初步研究。结论:三叶香茶菜乙酸乙酯部位浸膏中可能含有糖、多糖、苷类、皂苷、有机酸、黄酮类、酚类、香豆素、内酯、植物甾醇、三萜类等化学成分,为进一步研究壮药三叶香茶菜乙酸乙酯部位的化学成分和药理作用提供依据。     

瑶药裙头裆化学成分预实验

目的:初步分析瑶药裙头裆所含化学成分的类别.方法:通过化学显色反应、沉淀反应及滤纸片反应等方法对裙头裆水提取液、95％乙醇提取液及乙醚提取液进行化学成分预实验,初步分析裙头裆中含有的化学成分.结果:瑶药裙头裆中含有糖类、多糖或苷类、有机酸、酚类化合物、甾体及三萜类化合物、油脂类物质、强心苷类、内脂、香豆素及其苷类等成分.结论:为裙头裆的化学成分研究及其进一步开发利用奠定初步的基础.     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

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.     

Cooler temperatures inductive to locust outbreaks

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.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

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.     

Low doses of a red wine ingredient figh diabetes in mice

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.     

The Role of Intermediating Institutions in the Diffusion of Electronic Data Interchange (EDI): How Industry Associations Intervened in Denmark, Finland, and Hong Kong

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.     

How Electronic Publishers are Protecting Against Piracy: Doubts About Technical Systems of Protection

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.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.     

Prevalence of soft neurological signs in Chinese people

Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.     

Molecular motor assembly of a biomimetic system

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.     

Monoculture Rubber Plantations Have Negative Ef ects on Controlling Splash Erosion

<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence