论网络环境下的外刊阅读教学

飞速发展的互联网为外语教学提供了大量的资源，网络资源在外语教学中已经得到普遍的重视。充分认识利用网络资源进行外刊阅读教学的优点和存在的问题，对优化网络环境下外刊阅读教学有现实意义。     

ATM damage response and XLF repair factor are functionally redundant in joining DNA breaks

Classical non-homologous DNA end-joining (NHEJ) is a major mammalian DNA double-strand-break (DSB) repair pathway. Deficiencies for classical NHEJ factors, such as XRCC4, abrogate lymphocyte development, owing to a strict requirement for classical NHEJ to join V(D)J recombination DSB intermediates. The XRCC4-like factor (XLF; also called NHEJ1) is mutated in certain immunodeficient human patients and has been implicated in classical NHEJ; however, XLF-deficient mice have relatively normal lymphocyte development and their lymphocytes support normal V(D)J recombination. The ataxia telangiectasia-mutated protein (ATM) detects DSBs and activates DSB responses by phosphorylating substrates including histone H2AX. However, ATM deficiency causes only modest V(D)J recombination and lymphocyte developmental defects, and H2AX deficiency does not have a measurable impact on these processes. Here we show that XLF, ATM and H2AX all have fundamental roles in processing and joining DNA ends during V(D)J recombination, but that these roles have been masked by unanticipated functional redundancies. Thus, combined deficiency of ATM and XLF nearly blocks mouse lymphocyte development due to an inability to process and join chromosomal V(D)J recombination DSB intermediates. Combined XLF and ATM deficiency also severely impairs classical NHEJ, but not alternative end-joining, during IgH class switch recombination. Redundant ATM and XLF functions in classical NHEJ are mediated by ATM kinase activity and are not required for extra-chromosomal V(D)J recombination, indicating a role for chromatin-associated ATM substrates. Correspondingly, conditional H2AX inactivation in XLF-deficient pro-B lines leads to V(D)J recombination defects associated with marked degradation of unjoined V(D)J ends, revealing that H2AX has a role in this process.     

论大学学报的二重属性

大学学报不是普通的期刊,它是对高等学校主办的学术期刊的统称。大学学报是一个独特的学术期刊群,与技术性期刊、检索性期刊、科普性期刊、综合性期刊等其它四种科技期刊具有明确的界线,与非高校主办的学报也有根本区别。大学学报的特殊性是由其本质决定的。通过历史的和现实的考察分析得出:大学学报具有二重属性,不仅具有一般期刊共有的传媒性,又具有一般期刊没有的教育性。揭示大学学报的本质,是研究高校学报改革的前提。