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电信普遍服务若干问题研究
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作者 姜爱林 《天府新论》 2006年第4期52-58,共7页
被广泛接受的关于电信普遍服务的定义传达了普遍、平等、可支付三个方面的基本含义。电信普遍服务是一个不断发展的概念。从经济学角度来考察,虽然电信普遍服务不具备严格的公共产品属性,即非抗争性和非排他性,但是,由于其具有公共福利... 被广泛接受的关于电信普遍服务的定义传达了普遍、平等、可支付三个方面的基本含义。电信普遍服务是一个不断发展的概念。从经济学角度来考察,虽然电信普遍服务不具备严格的公共产品属性,即非抗争性和非排他性,但是,由于其具有公共福利性质,所以,单纯依靠市场机制的方法将不能保证有效的提供,而需要由政府这只“有形的手”来直接干预,通过制订相应的公共政策以确保对电信普遍服务的供给。在发展中国家,信息差距实际上是一种财富创造能力的差距,即贫富差距,信息差距导致的贫富差距容易加剧社会分化,引发社会动荡。 展开更多
关键词 电信普遍服务 内涵 目标 成本 效益 定义 非抗争性 公共产品属性 市场机制
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免费的午餐吃不久
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作者 灵雨 《价格辑刊》 2002年第6期37-38,共2页
关键词 公共物品 排他性 非抗争性 公共支出 市场机制 投票方式
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Affinity peptide developed by phage display selection for targeting gastric cancer 被引量:12
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作者 Wen-Jie Zhang Yan-Xia Sui +5 位作者 Arun Budha Jian-Bao Zheng Xue-Jun Sun Ying-Chun Hou Thomas D Wang Shao-Ying Lu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第17期2053-2060,共8页
AIM:To develop an affinity peptide that binds to gastric cancer used for the detection of early gastric cancer.METHODS:A peptide screen was performed by biopanning the PhD-12 phage display library,clearing non-specifi... AIM:To develop an affinity peptide that binds to gastric cancer used for the detection of early gastric cancer.METHODS:A peptide screen was performed by biopanning the PhD-12 phage display library,clearing non-specific binders against tumor-adjacent normal appearing gastric mucosa and obtaining selective binding against freshly harvested gastric cancer tissues.Tumortargeted binding of selected peptides was confirmed by bound phage counts,enzyme-linked immunosorbent assay,competitive inhibition,fluorescence microscopy and semi-quantitative analysis on immunohistochemistry using different types of cancer tissues.RESULTS:Approximately 92.8% of the non-specific phage clones were subtracted from the original phage library after two rounds of biopanning against normal-appearing gastric mucosa.After the third round of positive screening,the peptide sequence AADNAKTKSFPV(AAD) appeared in 25%(12/48) of the analyzed phages.For the control peptide,these values were 6.8 ± 2.3,5.1 ± 1.7,3.5 ± 2.1,4.6 ± 1.9 and 1.1 ± 0.5,respectively.The values for AAD peptide were statistically signif icant(P < 0.01) for gastric cancer as compared with other histological classif ications and control peptide.CONCLUSION:A novel peptide is discovered to have a specific binding activity to gastric cancer,and can be used to distinguish neoplastic from normal gastric mucosa,demonstrating the potential for early cancer detection on endoscopy. 展开更多
关键词 Gastric cancer Peptide Phage library Molecular imaging Early detection Immunohistochemistry Enzyme-linked immunosorbent assay
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