Homoharringtonine induces apoptosis of endothelium and down-regulates VEGF expression of K562 cells

Homoharringtonine (HHT) has currently been used successfully in the treatment of acute and chronic myeloid leukemias and has been shown to induce apoptosis of different types of leukemic cells in vitro. Emerging evidence suggests that angiogenesis may play an important role in hematological malignancies, such as leukemia. How ever, whether HHT can relieve leukemia by anti-angiogenesis is still unknown. We investigated the anti-angiogenesis potential of HHT with the human umbilical vein endothelial cell line (ECV304) and leukemic cell line (K562) in vitro. Cellular proliferation was determined by MTT assay and apoptosis was analyzed by flow cytometry. The mRNA expression of vascular endothelial growth factor (VEGF) was assessed by RT-PCR and VEGF protein production was detected by Western blot. Inhibition of cell proliferation and induction of apoptosis by HHT were discovered in ECV304 cells, and appeared in a dose- and time-dependent manner. Also, treatment with HHT caused down-regulation of VEGF mRNA expression in K562 cells in similar dose- and time-dependent manner and inhibition of VEGF protein production in K562 cells in response to the enhancing concentration of HHT. The results demonstrated that HHT could also induce apoptosis in endothelium and down-regulate VEGF expression in K562 cells. In conclusion, we believe HHT has anti-angiogenesis potential and speculate that HHT might exert its anti-leukemia effects via reduction of angiogenesis.     

一类超二次Hamilton系统的周期解的存在性

运用临界点理论中的极小、极大方法得到一类超二次哈密顿系统的周期解的存在性的存在性定理.     

Physical design method of MPSoC

Floorplan, clock network and power plan are crucial steps in deep sub-micron system-on-chip design. A novel di- agonal floorplan is integrated to enhance the data sharing between different cores in system-on-chip. Custom clock network con- taining hand-adjusted buffers and variable routing rules is constructed to realize balanced synchronization. Effective power plan considering both IR drop and electromigration achieves high utilization and maintains power integrity in our MediaSoC. Using such methods, deep sub-micron design challenges are managed under a fast prototyping methodology, which greatly shortens the design cycle.     

长光程薄层光谱电化学技术及应用

提供电子转移反应实验研究的实验装置及技术，依此可获得电子转移数、式电极电势、式异相电子转移速率常数、电子传递系数及还原态和氧化态的扩散系数等一系列重要的电化学参数。还可依此为基础设计出新颖、实用的教学实验。     

课程改革中教师关注阶段理论的研究述评

本文介绍了"关注阶段"的理论架构与评定方法,回顾并分析了它在美国、比利时、荷兰、香港以及澳大利亚等文化情境中的运用与发展.在我国新课程改革背景下进行关注阶段研究不仅有利于我们了解新课程实施情况,而且有助于这一理论自身的发展.     

集群式计算机系统在生物信息学中的应用

1　Introduction　SMP (symmetricmulti processing)andMPP (mas sivelyparallelprocessing)arethetwotypesofstruc tureofparallelcomputing .　Symmetricmulti processingsystemshavemultipleCPUsattachedtothesamebusandsharingRAM .Massivelyparallelprocessingisthecooperated pro cessingofaprogrambymultipleprocessorsthatworkondifferentpartsoftheprogram ,witheachprocessorusingitsownoperatingsystemandmemory .ThechoicebetweenSMPandMPPdependsonthenatureoftheproblembeingsolved .Iftheproblemcanbeeasilypartit…     

对Bermond猜想(32)的一个注记

文章对Bermand猜想（2）加强条件后给出了证明。     

Analysis on Chinese/English Code-Switching in Computer-Mediated Communication Based on Meme Theory

Nowadays,computer-mediated communication(CMC) becomes one of the most convenient ways for people to connect with each other in which Chinese/English code-switching has been frequently used and widely spread.The article will memeticly interpret this language phenomenon based on the authentic examples collected from various kinds of CMC,and point out that the Chinese/English code-switching in CMC is a kind of strong memeplex which includes many different strong memes,resulting in the popularity of Chinese/English code-switching in CMC.     

课程内容研究的新视野——TIMSS课程分析工具“主题追踪图”的演进与启示

美国密歇根州立大学施密特教授等人研究开发并完善的TIMSS"主题追踪图"作为重要的整体性课程分析工具,其使用的建模方法有效弥补了传统研究方法的不足。本文通过检索"主题追踪图"的演变轨迹,认为基于该工具的国际课程比较能全面反映各国课程在主题选择与组织层面的异同,而构建的课程连贯性理想模型更是提供了一种全新的课程内容研究思路与范式。     

基于构造-剪枝混合优化RBF网络的煤灰熔点预测方法

为提高煤灰熔点的预测精度,提出了一种基于构造-剪枝混合优化RBF网络的煤灰熔点预测方法.该方法融合了神经网络构造算法和剪枝算法的优点,分为“粗调”和“精调”2个阶段.粗调阶段动态增加隐节点数目直至满足相应的停止准则;精调阶段对粗调得到的RBF网络的结构和参数作进一步调整.基于煤灰的化学组成成分建立相应的构造-剪枝混合优...