共查询到20条相似文献，搜索用时 490 毫秒
1.
本文对青藤碱凝胶剂的质量标准进行研究。方法:采用卡赛帕克C18MG液相色谱柱(218 mm×4.6mm,5μm),甲醇-0.2mol/L磷酸氢二钠-0.2mol/L磷酸二氢钠(50:30:20),检测波长为262nm,流速为1.0ml/min,柱温为30℃。青藤碱在0.24～1.2μg.mL-1范围内呈良好的线性关系(r=0.99996)。青藤碱平均回收率分别为99.3%。结论:本法简便、准确,可用于青藤碱凝胶剂的质量控制。 相似文献
2.
对盐酸小檗碱凝胶的质量标准进行研究。方法：采用安捷伦十八烷基硅烷键合硅胶色谱柱（218 mm×4.6mm,5μm）,0.033mol/L磷酸二氢钾溶液-乙腈（70：30）,检测波长为265nm,流速为1.0ml/min,柱温为30℃。盐酸小檗碱在2～20mg.mL-1范围内呈良好的线性关系（r=0.99995）。盐酸小檗碱平均回收率分别为99.5%。结论：本法简便、准确,可用于盐酸小檗碱凝胶的质量控制。 相似文献
3.
HPLC法测定铁棒锤中乌头碱的含量 总被引：3，自引：0，他引：3
目的建立HPLC测定铁棒锤中乌头碱的方法。方法采用高效液相色谱-紫外检测器;色谱柱为Thermo ODS-2 HYPERSIL Dim(.250mm×4.6mm,5μm);柱温为30℃;流动相为乙腈-0.3%二乙胺水溶液(35:65);流速为1.0ml/min。结果乌头碱在0.975μg-3.9μg(R=0.999)范围内线性关系良好。乌头碱加样回收率为98.06%,RSD%为1.2%,原药材中乌头碱的含量为0.1052mg/g。结论本实验建立的测定方法具有准确、简便、灵敏度高、无干扰而且重现性好的优点,适合用于铁棒锤中乌头碱含量的测定。 相似文献
4.
5.
本文采用高校液相测定了黄连配方颗粒及饮片中盐酸小檗碱的含量,固定相为:Waters XBridge C18液相色谱柱(150*4.6mm,5un),甲醇-乙腈-0.05mol/L磷酸二氢钾溶液(30:30∶40)(每100毫升中加入十二烷基硫酸钠0.4克,再用磷酸调PH为4.0)为流动相,检测波长为345nm;盐酸小檗碱在50~350μg·m L-1范围内呈良好的线性关系。盐酸小檗碱的平均回收率为99.6%,RSD为0.96%(n=6);此方法简便、准确、重现性好,可用于黄连配方颗粒及饮片中盐酸小檗碱的含量测定。 相似文献
6.
本实验研究莲子心总碱缓释片的制备方法并建立反相高效液相色谱法测定莲子心总碱缓释片中莲子心碱的含量。方法:采用安捷伦十八烷基硅烷键合硅胶色谱柱(218 mm×4.6mm,5μm),乙腈-0.015mol/L十二烷基磺酸钠溶液(取十二烷基磺酸钠0.41g加水100ml使溶解)-冰醋酸(56:43:1),检测波长为282nm,流速为1.0ml/min,柱温为30℃。莲子心碱在0.5～2.5μg.mL-1范围内呈良好的线性关系(r=0.9999)。结论:本制剂稳定、可靠,测定方法简便、准确。 相似文献
7.
8.
《大众科技》2020,(2)
目的:建立HPLC(高效液相色谱)测定蓖麻叶提取物中槲皮素、绿原酸、蓖麻碱3种活性成分的方法。方法:使用岛津LC-20A的高效液相色谱仪,采用Shim pack GIST C18色谱柱(4.6 mm×250 mm,5μm);流动相为甲醇和0.4%磷酸水溶液,梯度洗脱,流速为1.0 mL/min,检测波长327 nm,柱温30℃。结果:蓖麻碱、绿原酸和槲皮素在0.06 mg/mL～0.36 mg/mL、0.04mg/m L～0.24mg/m L和0.003mg/m L～0.018mg/m L的进样量范围内与峰面积呈良好线性关系(R2分别为0.9998,0.9996和0.9992),且精密度、稳定性和重复性良好,回收率在98.31%～99.63%之间。结论:本研究建立的HPLC法测定蓖麻叶中蓖麻碱、绿原酸和槲皮素3个成分的含量高效、准确、重复性好,可用于蓖麻叶及相关药材的质量控制。 相似文献
9.
本文用高效液相法对钩藤中的钩藤碱的进行了含量测定。固定相为:依利特hypersil BDS C18色谱柱(4.6*250*5u),乙腈和0.01mol/L醋酸铵溶液梯度洗脱为流动相,漂移管温度为105摄氏度;载气流速为3.0ml/min;放大倍数为2;钩藤碱在0.1~1.8mg·m L-1范围内呈良好的线性关系。钩藤碱的平均回收率为99.5%。本法简便、重现性好、回收率高,可用于钩藤中钩藤碱的含量测定。 相似文献
10.
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.
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
13.
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
14.
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
15.
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
16.
《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
17.
《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
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