雪莲果染色体数目及核型分析

雪莲果为菊科多年生双子叶草本植物,容易产生变异形成新的种系,为了确定我国引种雪莲果的染色体数目,采用0.002 M的8-羟基喹啉溶液预处理雪莲果根尖3～4 h,经卡诺氏液固定、酸解去壁、卡宝品红染色等步骤,对雪莲果进行了染色体数目的确定及体细胞染色体核型分析,结果表明雪莲果的染色体数目为2n=52=30m+22sm,核...     

O2流量对O2/C4F8等离子体刻蚀SiCOH低k薄膜的影响

研究了O2/C4F8等离子体刻蚀SiCOH低k薄膜时O2流量对刻蚀率、表面结构的影响,及其放电等离子体特性的关联.发现O2流量的增大可以极大地提高多孔SiCOH薄膜的刻蚀速率,降低表面的粗糙度,减少SiCOH薄膜表面的C:F沉积.等离子体特性的光谱分析表明,O2的添加,增强了C与O之间的反应,从而在Si、F反应刻蚀Si的同时,C、O之间的反应使C消耗,实现Si、C的同步刻蚀,从而获得SiCOH低k薄膜的高刻蚀率和低粗糙度表面.     

钢框架稳定性探讨

钢框架稳定性的计算主要是柱子稳定性的计算,其中计算长度系数法避免了对结构做整体屈曲分析,因此得到广泛应用.钢框架柱的计算长度系数与多因素有关,体现在初始几何缺陷、荷载条件、节点连接刚度、支撑刚度、层间相互作用和二阶效应等方面.但钢框架的整体稳定判定准则也起着越来越重要的作用.     

核磁共振在蛋白质研究中的应用进展

蛋白质是一类重要的生物大分子,在生物体内执行各种各样的生理功能.自18世纪蛋白质被发现以来,蛋白质研究的重点从早期的分离纯化逐渐深入到结构与功能.     

浅析移动通信中MSC POOL的原理及应用

MSC POOL是近年来在移动通信网络中引入的一种新组网方式,它的出现改变 了以往单一的组网模式,使得移动通信网络的应用变得更为灵活,提升了整个移动通信核心网的资源利用率,节省设备投资,提高了网络可靠性和用户通话质量.     

MSTP在镇江电力通信传输网的应用

文章介绍了基于SDH的多业务传送设备MSTP的概念特点及关键技术,分析了MSTP在镇江电力通信传输网以太网业务的应用。     

In vivo genome editing restores haemostasis in a mouse model of haemophilia

Editing of the human genome to correct disease-causing mutations is a promising approach for the treatment of genetic disorders. Genome editing improves on simple gene-replacement strategies by effecting in situ correction of a mutant gene, thus restoring normal gene function under the control of endogenous regulatory elements and reducing risks associated with random insertion into the genome. Gene-specific targeting has historically been limited to mouse embryonic stem cells. The development of zinc finger nucleases (ZFNs) has permitted efficient genome editing in transformed and primary cells that were previously thought to be intractable to such genetic manipulation. In vitro, ZFNs have been shown to promote efficient genome editing via homology-directed repair by inducing a site-specific double-strand break (DSB) at a target locus, but it is unclear whether ZFNs can induce DSBs and stimulate genome editing at a clinically meaningful level in vivo. Here we show that ZFNs are able to induce DSBs efficiently when delivered directly to mouse liver and that, when co-delivered with an appropriately designed gene-targeting vector, they can stimulate gene replacement through both homology-directed and homology-independent targeted gene insertion at the ZFN-specified locus. The level of gene targeting achieved was sufficient to correct the prolonged clotting times in a mouse model of haemophilia B, and remained persistent after induced liver regeneration. Thus, ZFN-driven gene correction can be achieved in vivo, raising the possibility of genome editing as a viable strategy for the treatment of genetic disease.     

完全支持数据更新的XML压缩编码

为了有效地更新和查询XML数据,提出了一种新的XML编码方案-分数路径编码(简写为FAPE).FAPE充分利用在两个分数间可以插入无穷多个分数这一特点,支持XML结点数据的无限更新,同时FAPE将结点的相关信息保存在相应的表中,避免记录重复的信息.实验表明:FAPE节省了存储空间,提高了查询效率,更新所花的时间更少.     

可约矩阵特征值的扰动

主要研究可约矩阵特征值的扰动.对于可约矩阵,给出了Bauer-Fike型的一些结果,这些结果推广了文献[3-5]中相应的结果.