Sea urchin embryo as a model for analysis of the signaling pathways linking DNA damage checkpoint,DNA repair and apoptosis

DNA integrity checkpoint control was studied in the sea urchin early embryo. Treatment of the embryos with genotoxic agents such as methyl methanesulfonate (MMS) or bleomycin induced the activation of a cell cycle checkpoint as evidenced by the occurrence of a delay or an arrest in the division of the embryos and an inhibition of CDK1/cyclin B activating dephosphorylation. The genotoxic treatment was shown to induce DNA damage that depended on the genotoxic concentration and was correlated with the observed cell cycle delay. At low genotoxic concentrations, embryos were able to repair the DNA damage and recover from checkpoint arrest, whereas at high doses they underwent morphological and biochemical changes characteristic of apoptosis. Finally, extracts prepared from embryos were found to be capable of supporting DNA repair in vitro upon incubation with oligonucleotides mimicking damage. Taken together, our results demonstrate that sea urchin early embryos contain fully functional and activatable DNA damage checkpoints. Sea urchin embryos are discussed as a promising model to study the signaling pathways of cell cycle checkpoint, DNA repair and apoptosis, which upon deregulation play a significant role in the origin of cancer. Received 10 April 2007; accepted 23 April 2007     

TTDN1 is a Plk1-interacting protein involved in maintenance of cell cycle integrity

Polo-like kinase 1 (Plk1) is a highly conserved serine/threonine kinase that plays critical roles in many cell cycle events, especially in mitosis. In the present study, we identified TTDN1 as a potential interacting partner of Plk1 in yeast two-hybrid screens. Sequence analysis indicates that TTDN1 contains a consensus Plk1-binding motif at its C terminus. TTDN1 colocalizes with Plk1 at the centrosome in mitosis and the midbody during cytokinesis. TTDN1 is phosphorylated by Cdk1 in mitosis, and this is required for its interaction with Plk1. Site-directed mutagenesis indicates that TTDN1 is phosphorylated at multiple residues, including Ser93 and Ser104. Mutation of Thr120 of TTDN1 abolishes its interaction with Plk1, suggesting phosphorylation of Thr120 in the consensus Plk1-binding motif is required for its interaction with Plk1. Overexpression of TTDN1 or its knockdown by siRNA causes multi-polar spindles and multiple nuclei, suggesting that TTDN1 plays a role in regulating mitosis and cytokinesis. Received 27 November 2006; received after revision 4 January 2007; accepted 25 January 2007 Y. Zhang, Y. Tian: These authors contribute equally to this work.     

绿色再制造管理层次网络分析模型及应用

绿色再制造管理是对产品再制造加工各个环节进行管理的有效模式。针对目前绿色再制造实施过程环节多,影响因素复杂,再制造实施缺乏系统研究的现状,分析了绿色再制造战略实施的影响因素和控制要素,提出了一种集成绿色再制造各个环节的层次网络分析模型。基于ANP分析理论,用实例说明了采用ANP法进行绿色再制造管理战略决策的过程。     

燃气-蒸汽联合循环机组热力系统动态仿真模型

采用模块化建模方法开发了燃气-蒸汽联合循环机组热力系统动态仿真模型.根据联合循环机组工作机理和特性,以质量、能量、动量平衡原理为基础,结合相关专业基础知识,论述了燃气顶循环和蒸汽底循环系统中主要设备和过程仿真模块的数学模型及建模思路,与热力系统中其它辅助设备仿真模块相结合,以深圳广前电力有限公司M701型燃气-蒸汽联合循环机组为对象,建立了完整的联合循环机组热力系统机理性实时仿真模型.仿真试验表明所建模型能够正确反映参照机组热力系统的动态特性和全工况运行过程,整体模型运算稳定可靠,不仅可用于机组运行人员的仿真培训,还可为联合循环机组控制系统设计与分析提供良好的非线性对象模型.     

Polycystic kidney diseases: From molecular discoveries to targeted therapeutic strategies

Polycystic kidney diseases (PKDs) represent a large group of progressive renal disorders characterized by the development of renal cysts leading to end-stage renal disease. Enormous strides have been made in understanding the pathogenesis of PKDs and the development of new therapies. Studies of autosomal dominant and recessive polycystic kidney diseases converge on molecular mechanisms of cystogenesis, including ciliary abnormalities and intracellular calcium dysregulation, ultimately leading to increased proliferation, apoptosis and dedifferentiation. Here we review the pathobiology of PKD, highlighting recent progress in elucidating common molecular pathways of cystogenesis. We discuss available models and challenges for therapeutic discovery as well as summarize the results from preclinical experimental treatments targeting key disease-specific pathways. Received 8 August 2007; received after revision 19 September 2007; accepted 2 October 2007     

Detecting and Predicting Economic Accelerations,Recessions, and Normal Growth Periods in Real‐Time

The dichotomous characterization of the business cycle in recessions and expansions has been central in the literature over the last 50 years. However, there are various reasons to question the adequacy of this dichotomous, recession/expansion approach for our understanding of the business cycle dynamics, as well as for the prediction of future business cycle developments. In this context, the contribution of this paper to the literature is twofold. First, since a positive rate of growth at the level of economic activity can be considered as the normal scenario in modern economies due to both population and technological growth, it proposes a new non‐parametric algorithm for the detection and dating of economic acceleration periods, trend or normal growth periods, and economic recessions. Second, it uses an ordered probit framework for the estimation and forecasting of these three business cycle phases, applying an automatized model selection approach using monthly macroeconomic and financial data on the German economy. The empirical results show that this approach has superior out‐of‐sample properties under real‐time conditions compared to alternative probit models specified individually for the prediction of recessions and/or economic accelerations. Copyright © 2016 John Wiley & Sons, Ltd.     

用"最小状态、最大状态"法分析任意进制计数器

针对用定型计数器产品构成其它进制的计数器电路,提出一种简明分析法。利用电路输出信号的最小状态、最大状态,以及状态有效循环路径,确定电路的进制。将该方法应用到实例中,取得了较好的效果。     

一类具有稀疏效应下食饵—捕食系统极限环的存在唯一性

研究如下一类具有稀疏效应的食饵一捕食模型dx/dt=ax（x-L）（b-x）-bxy,dy/dt=-cy＋（βx-ry）y,应用常微分方程定性理论,对该系统的平衡点进行分析,得到了极限环存在唯一性的充分条件。     

实心圆轴拉扭组合全寿命实验中应力按比例加载的控制方法

针对实心圆轴拉、扭组合实验全寿命过程中拉(σ)、扭(τ)应力按固定比例加载的难题,基于拉扭试验机控制的核心问题,从弹性应力比C(σ/τ)的概念出发,推导出载荷比F/T(轴力/扭矩)控制参数,同时考虑全寿命中的拉扭真应力关系,给出载荷程序控制路线,应用PID方式实现试验机控制。以304不锈钢及16MnR碳钢为研究对象,进行了24组不同C的拉扭实验。在此基础上,以塑性过程中的真应力比槇C(σ/τ)为依据,提出了比例修正系数C'的概念,解决了试验机在全过程的控制问题。结果表明:以C为基础的控制模式可对弹性阶段精确控制;材料进入塑性后,C的差异与材料无关,仅与控制方法有关;将提出的C引入控制程序后,可有效提高全寿命过程中应力按比例加载的准确性。     

钢筋环扣连接的叠合梁柱节点力学性能研究

提出一种叠合梁柱节点的钢筋环扣连接技术,对4个试件进行低周往复加载试验,研究节点的滞回性能,耗能能力、刚度退化等力学性能。试验结果表明：钢筋环扣连接节点在低周往复荷载作用下的承载力和刚度退化方面优于现浇与弯锚节点。在此基础上,采用ABAQUS对不同弯折高度的钢筋环扣连接节点进行单调加载计算分析,参数分析结果表明：增加钢筋环扣的弯折高度会降低节点的抗弯刚度,但在节点受拉钢筋屈服后,其承载力下降较缓。