Notch and cancer: a double-edged sword

The highly conserved Notch signaling pathway plays pleiotropic roles during embryonic development and is important for the regulation of selfrenewing tissues. The physiological functions of this signaling cascade range from stem cell maintenance and influencing cell fate decisions of barely differentiated progenitor cells, to the induction of terminal differentiation processes, all of which have been found to be recapitulated in different forms of cancers. Although Notch signaling has mostly been associated with oncogenic and growth-promoting roles, depending on the tissue type it can also function as a tumor suppressor. Here we describe recent findings on Notch signaling in cancer and tumor angiogenesis, and highlight some of the therapeutic approaches that are currently being developed to interfere with tumor growth and progression. Received 2 April 2007; received after revision 29 June 2007; accepted 2 July 2007     

外源钙缓冲作用的动力学模型

外源钙缓冲具有调控细胞内钙信号的功能。最近的实验表明慢速和快速外源钙缓冲的作用均能降低胞质钙振荡的振幅和钙瞬变的衰减率。将外源钙缓冲的影响导入至Atri等人的模型中,分别得到了慢速钙缓冲作用的三变量模型和快速钙缓冲作用的二变量模型。模型表明外源钙缓冲物的作用,不仅降低了钙信号的振幅和衰减率,还降低了周期振荡的频率。并且,模型预测存在一个钙缓冲物浓度的最小值,可以消除周期振荡。     

非对称需求信息条件下的供应链信息共享机制

缺乏有效的信息共享是供应链运作效率低下的主要原因之一，而信息不对称问题广泛存在于供应链之中．面临低市场需求的零售商有可能夸大真实的市场需求以获得更多的产品供应．运用信号传递博弈理论研究了供应链中零售商和供应商之间的共享需求信息的机制，得出了零售商可以通过采购价格向供应商传递真实的市场需求信息的条件，结果表明供应商和零售商之间的信息共享的关键在于分离均衡的存在，分离均衡使得供应商能够得到足够的信息量借以识别零售商的市场预测的真实性．     

Matrix metalloproteinase 19 processes the laminin 5 gamma 2 chain and induces epithelial cell migration

In this study we analyzed the proteolytic activity of MMP-19 and its impact on keratinocyte migration. In the HaCaT keratinocyte cell line overexpressing wild-type MMP-19 (HaCaT-WT), transmigration through fibrin and type IV collagen matrices was significantly increased compared to cells harboring a catalytically inactive mutant (HaCaT-EA). Studying the expression of MMP-19 in early stages of squamous cell cancer (SCC), we found co-localization of MMP-19 and laminin 5 at the invading tumor front but not in suprabasal epidermis of the tumor. Examination of laminin 5 processing revealed increased processing of the 2 chain in the medium and matrix of HaCaT-WT cells and degradation by recombinant human MMP-19 to 105-kDa and 80-kDa fragments. Parental HaCaT grown on the matrix of HaCaT-WT and HaCaT-EA cells displayed differential tyrosine phosphorylation. Using integrin blocking and stimulating antibodies we could attribute these differences to a shift from 4-integrin-dependent signaling on the HaCaT-EA matrix toward 3-integrin-dependent signaling on the HaCaT-WT matrix. As a consequence, parental HaCaT showed increased migration on the matrix of HaCaT-WT cells. These data suggest that the MMP-19-dependent processing of the 2 chains leads to the integrin switch favoring epithelial migration and that MMP-19 actively participates in the early stages of SCC invasion.Received 29 October 2004; received after revision 7 December 2004; accepted 17 January 2005     

移动自组网络及其服务质量

随着无线技术和基于此技术之上的应用发展，提供了在移动自组网络中引入服务质量的依据。在介绍了QoS的体系结构后，重点介绍QoS模式以及需要提供给QoS模式的进程机制，再对4种模式进行比较评估。最后通过7条准则描述对QoS有要求的应用程序的特性，说明了这些准则是如何影响QoS体系结构选择的。     

7号信令监测系统在互联互通业务中的研究与实现

在互联互通业务中应用7号信令集中监测系统，可以为电信运营商进行市场分析和制定经营策略提供重要的帮助。在深入研究7号信令网和7号信令监测系统基本原理的基础上，提出了一种新的信令事件合成方法，并详述了这种方法的基本思路和具体的实施方式，最后给出了采用该方法的监测系统在互联互通业务中的具体实现方案。     

信号博弈及转轨时期商业银行信贷行为的理论解释

从信号博弈的角度解释经济转轨时期商业银行与企业之间的信贷行为,分析了转轨时期我为商业银行大量不良债权形成的微观机理;指出转轨时期的一些特殊因素使得信贷抵钾、担保等都难以成为企业对银行发出的有信息价值的信号,制度上的规定也使得信贷利率失去信号的作用。企业的信贷参与约束条件很容易得到满足,从而信贷博弈难以达成银行所期望的分离均衡。转轨时期银行的信贷参与约束条件也较容易达成,而后期较大的清算交易费用使得大量的不良债权滞留下来。     

Kaposi＇s sarcoma-associated herpesvirus. Towards better understanding of its latency and pathogenesis

Kaposi＇s sarcoma-associated herpesvirus （KSHV） is a double stranded DNA virus. It was found to be related to Kaposi＇s sarcoma （KS）, primary effusion lymphoma （PEL） and multicentric Castleman＇s disease （MCD）, which cause severe illness in AIDS patients. As a member of human herpesvirus family, KSHV displays two distinct phases in its life cycle, the default latent and lytic replication phase. Following primary infection, the virus can quickly establish latent infection in the host. However, it is still not fully understood up to date how KSHV establishes and maintains viral latency in the host cells. KSHV mainly infects endothelial cells in the host, promoting proliferation and angiogenesis. Abundant angiogenesis is the key feature of KS and is the critical factor for KS progression. The mechanism of KSHV mediated pathogenesis is also largely unknown. In this review, we summarize the recent progress in the mecha- nisms of KSHV latency and pathogenesis, with particular views from our work.     

视频分发技术研究

针对网络服务商提供视频服务部署成本过高问题,提出一种提供弹性服务的方法.首先,根据抽样原理建立不同点播时段请求到达率的预测模型;在此基础上应用流模型、微分方程稳定性理论和信号博弈原理建立了系统提供弹性服务的方法.该方法能够有效降低服务商的部署成本,提高系统的可扩展性和视频分发质量;最后通过仿真实验验证了提出方法的可行性...     

列车运行系统中接口电路的设计

叙述了仿真系统中仿真接口电路的功能和设计方法，给出了仿真接口的硬件电路设计和软件编程方法，论述了仿真系统主机与接口电路以及接口电路与被调试样机之间的通讯协议规程，对仿真接口电路的可靠性问题也做了一定的分析。