壳聚糖三维材料的制备及其应用研究进展

在生物材料的研究领域中,有关壳聚糖材料的制备与应用研究越来越受到重视,由于壳聚糖特殊的结构与性能导致壳聚糖三维材料的制备极其困难。本文着重介绍近年来壳聚糖三维材料制备研究的进展,重点是为三维壳聚糖无机复合材料、三维壳聚糖磁性功能材料、三维壳聚糖增强材料、三维壳聚糖仿生材料以及三维壳聚糖组织工程支架材料的研究进展及各材料的性能与应用方向;展望了壳聚糖三维材料的发展前景,特别是提高壳聚糖三维材料的力学性能以及在人体内环境下力学性能的耐衰减能力,在生物可降解骨折内固定材料与生物可降解骨组织工程的应用上起着决定作用,将是未来几年壳聚糖三维材料研究的重点和突破口。     

壳聚糖三维支架研究进展

近十年,生物高分子材料的发展突飞猛进,国内外学者对于医学应用领域中炙手可热的生物高分子——壳聚糖的研究更是有如井喷之势。本文综述了近几年国内外学者在组织工程应用研究领域中的多种壳聚糖复合支架的制备方法及其特性,尤其着重综述了骨组织工程领域和皮肤组织工程领域中的多种壳聚糖复合支架的制备方法和特性。并对壳聚糖复合支架在组织工程中的发展进行了展望,认为增强支架的生物相容性,提高复合支架的力学性能,将是未来几年中壳聚糖复合支架研究的重心所在。     

壳聚糖/海藻酸钠纳米粒的制备研究进展

本文综述了壳聚糖/海藻酸钠纳米粒的制备方法,并讨论了壳聚糖/海藻酸钠纳米粒的应用前景和目前存在的问题。     

抄纸法制备壳聚糖薄膜材料的研究

壳聚糖属于天然多糖类生物大分子,具有优良的成膜性能和抗菌性能,传统制备壳聚糖薄膜材料的工艺太长,成本高,不利于大规模生产。本文使用一种简单的壳聚糖成膜方法,即采用中和滴定法制备壳聚糖凝絮浆液,用传统的抄纸法制得壳聚糖薄膜。通过正交表试验及单因素研究,以柔软性能的好坏作为薄膜性能的标准,最终确定了最佳壳聚糖薄膜形成的条件,并对壳聚糖薄膜的表面形态进行了表征。     

摇旗的机器人

在美国纽约特罗伊实验室里，两面小旗来回摇动．这是人造肌肉给出的摇旗信号。这两面小旗安装在聚合物艇胶体的电极上，当给它与人体肌肉收缩速度一样的脉冲信号时，它能作出反应。研究人员认为．这是研究人员和假肢制造者花了几十年时间．向“人造肌肉”研究迈出的重要一步。     

由钛精矿制备人造金红石的研究进展

综合评述了国内外由钛精矿制备人造金红石的研究方法及工艺特点。通过对各种研究工艺的对比找到最佳的研究方法,以期对我国人造金红石的发展提供有益的启示。     

头孢曲松钠壳聚糖微球制备工艺初探

本文对头孢曲松钠壳聚糖微球制备工艺进行研究。     

壳聚糖及其衍生物在兽药及饲料添加剂中的应用前景

本文描述了壳聚糖的基本特性,壳聚糖衍生物的种类,壳聚糖及其衍生物的生理功能,介绍壳聚糖及其衍生物在兽药及饲料添加剂中的应用现状,并探讨了在此方面的应用前景,为其在兽药和饲料添加剂领域的研究和利用提供资料。     

南非用螃蟹壳制造新型绷带

南非科技与工业研究院（CSIR）的科学家正在研究螃蟹壳的抗菌性能,期望能找到一种基于壳聚糖的聚合物溶液配方,通过静电纺丝的方法制备出壳聚糖纳米纤维膜。由于具有特殊性能,壳聚糖纳米纤维膜特别适用于创伤治疗材料。     

基于分子模拟的壳聚糖微观结构分析

壳聚糖的微观结构可对其性质与功能产生重要影响,因此对于壳聚糖微观结构的研究具有重要意义.由于传统的实验手段很难深入地研究壳聚糖的微观结构,因此文章通过分子模拟技术对壳聚糖中的糖苷键、氢键的性质与特征,以及乙酰氨基对壳聚糖结构与性质的影响进行了计算与分析.结果 表明,壳聚糖糖苷键中O-C4键比C1-O键更容易断裂.壳聚糖的糖苷键比与乙酰氨基相邻的糖苷键更容易断裂.壳聚糖中形成氢键的主导因素并不是基团运动的自由程度,而是氢键中电子供体的负电荷数,负电荷数越高则形成的氢键强度越强.壳聚糖中氨基N与羟基H形成的氢键强度最强.研究结果对壳聚糖溶解和降解的研究及应用具有指导意义.     

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.     

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.     

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     

Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels

<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese     

More than Skin Deep – Understand Skin Biology by Means of Dermatogenomics

<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages.