Regulation of cell cycle progression and gene expression by H2A deubiquitination

Post-translational histone modifications have important regulatory roles in chromatin structure and function. One example of such modifications is histone ubiquitination, which occurs predominately on histone H2A and H2B. Although the recent identification of the ubiquitin ligase for histone H2A has revealed important roles for H2A ubiquitination in Hox gene silencing as well as in X-chromosome inactivation, the enzyme(s) involved in H2A deubiquitination and the function of H2A deubiquitination are not known. Here we report the identification and functional characterization of the major deubiquitinase for histone H2A, Ubp-M (also called USP16). Ubp-M prefers nucleosomal substrates in vitro, and specifically deubiquitinates histone H2A but not H2B in vitro and in vivo. Notably, knockdown of Ubp-M in HeLa cells results in slow cell growth rates owing to defects in the mitotic phase of the cell cycle. Further studies reveal that H2A deubiquitination by Ubp-M is a prerequisite for subsequent phosphorylation of Ser 10 of H3 and chromosome segregation when cells enter mitosis. Furthermore, we demonstrate that Ubp-M regulates Hox gene expression through H2A deubiquitination and that blocking the function of Ubp-M results in defective posterior development in Xenopus laevis. This study identifies the major deubiquitinase for histone H2A and demonstrates that H2A deubiquitination is critically involved in cell cycle progression and gene expression.     

H2O(Ⅰ)空间上的B-样条插值小波基

本文构造了Soblov空间H2O(Ⅰ)(其中Ⅰ为有界区间)上的一个五次B-样条插值小波基,这是一个半正交Riesz小波基.最后给出了小波基的公式.     

后注浆桩技术的应用研究

主要结合工程实例,介绍泥浆护壁钻孔灌注桩后注浆技术的机理、特点、施工工艺及技术要点.     

建设项目压覆矿产资源储量技术方法研究——以南水北调中线一期工程总干渠为例

首先对建设项目压覆矿产进行了分类,提出了压覆矿产的理论依据,并根据地质条件、岩石类型及力学特征、采矿技术等对压覆矿产资源储量技术方法进行了研究,提出露采边坡角和地下开采移动角的确定方法,提出了建设项目压覆范围确定方法和压覆范围内资源储量估算参数选取及估算方法,并应用于南水北调一期总干渠压覆核查中,结果表明,该方法是可靠、可行的.     

Deformation induced structural evolution in bulk metallic glasses

The structural behavior of binary Cu50Zr50 and ternary Cu50Zr45Ti5 bulk metallic glasses (BMGs) under applied stress was investigated by means of in-situ high energy X-ray synchrotron diffraction. The components of the strain tensors were determined from the shifts of the maxima of the atomic pair correlation functions (PDF) in real space. The anisotropic atomic reorientation in the first-nearest-neighbor shell versus stress suggests structural rearrangements in short-range order. Within the plastic deformation range the overall strain of the metallic glass is equal to the yield strain. After unloading,the atomic structure returns to the stress-free state,and the short-range order is identical to that of the undeformed state. Plastic deformation,however,leads to localized shear bands whose contribution to the volume averaged diffraction pattern is too weak to be detected. A concordant region evidenced by the anisotropic component is activated to counterbalance the stress change due to the atomic bond reorientation in the first-nearest-neighbor shell. The size of the concordant region is an important factor dominating the yield strength and the plastic strain ability of the BMGs.     

浅谈如何抓好班组安全日活动

班组是电力企业最活跃的细胞,是最基层的管理组织,是企业生存和发展的基础,是各项工作的落脚点。班组的素质直接反应出企业的素质,班组的安全水平和经济效益直接影响企业的安全基础和经济效益,因此加强班组安全管理,提高班组人员的安全意识和教育水平,就显得尤为重要。而班组安全日活动作为保证班组安全管理行之有效的方法之一,在班组安全管理工作中起着举足轻重的作用。通过活动,进行学习、定期分析工作中的不足、小结班组安全情况,进行自我教育,达到班组成员共同提高的目的,可以有效控制设备异常、减少事故的发生,从而为各项工作的开展打下坚实的基础。     

论“反思性”教师的培养

在教师的专业发展过程中,反思已成为最重要的自我发展手段。如何才能成为一名“反思性”教师,首先从反思性教师的概念及其特征出发,分析了教学反思的内容、过程和方法。并针对教学反思的最常见方法——听课评课中存在的问题提出了建议。     

试论公用事业改制中职工的思想动态及其对策

善于"疏导",深入到职工之中,倾听职工的心声,听取职工对改革的意见和建议,采用各种形式及时了解职工的思想动态及时分析、解决和化解矛盾,千方百计地稳定职工思想,促进职工转变不合时宜的观念,是确保公用事业改革顺利进行的关键所在。     

论构建和谐社会的技术观

工业技术观、生态技术观和文化主导技术观虽然适应了不同时代的需求,但割裂了技术与经济、自然、社会的有机联系,都与和谐社会的目标系统有一定差距。尝试运用马克思主义的立场、观点和方法,在研究分析各种技术观利弊的基础之上,提出构建和谐技术观的初步设想。     

粉煤灰机制砂混凝土在G208线夏店互通立交桥中的应用

结合工程实际分析了粉煤灰、机制砂掺入水泥混凝土后对混凝土特性的影响,为粉煤灰和机制砂在公路桥梁中的大量利用提供参考.