The p38/MAPK pathway regulates microtubule polymerization through phosphorylation of MAP4 and Op18 in hypoxic cells

In both cardiomyocytes and HeLa cells, hypoxia (1% O₂) quickly leads to microtubule disruption, but little is known about how microtubule dynamics change during the early stages of hypoxia. We demonstrate that microtubule associated protein 4 (MAP4) phosphorylation increases while oncoprotein 18/stathmin (Op18) phosphorylation decreases after hypoxia, but their protein levels do not change. p38/MAPK activity increases quickly after hypoxia concomitant with MAP4 phosphorylation, and the activated p38/MAPK signaling leads to MAP4 phosphorylation and to Op18 dephosphorylation, both of which induce microtubule disruption. We confirmed the interaction between phospho-p38 and MAP4 using immunoprecipitation and found that SB203580, a p38/MAPK inhibitor, increases and MKK6(Glu) overexpression decreases hypoxic cell viability. Our results demonstrate that hypoxia induces microtubule depolymerization and decreased cell viability via the activation of the p38/MAPK signaling pathway and changes the phosphorylation levels of its downstream effectors, MAP4 and Op18.     

从顺应论角度分析网络聊天室中的语码转换

语码转换是网络会话中常见的一种语言现象。以维索而伦的语言顺应性理论为基础,结合国内学者提出的语码转换的顺应对象：语言现实、社会规约和心理动机,对网络聊天室中的语码转换现象进行分析,旨在更好地了解语码转换与语言顺应之间的关系。     

Developing anti-neoplastic biotherapeutics against eIF4F

Biotherapeutics have revolutionized modern medicine by providing medicines that would not have been possible with small molecules. With respect to cancer therapies, this represents the current sector of the pharmaceutical industry having the largest therapeutic impact, as exemplified by the development of recombinant antibodies and cell-based therapies. In cancer, one of the most common regulatory alterations is the perturbation of translational control. Among these, changes in eukaryotic initiation factor 4F (eIF4F) are associated with tumor initiation, progression, and drug resistance in a number of settings. This, coupled with the fact that systemic suppression of eIF4F appears well tolerated, indicates that therapeutic agents targeting eIF4F hold much therapeutic potential. Here, we discuss opportunities offered by biologicals for this purpose.     

Discrete Euler processes and their applications

This paper introduces discrete Euler processes and shows their application in detecting and forecasting cycles in non‐stationary data where periodic behavior changes approximately linearly in time. A discrete Euler process becomes a classical stationary process if ‘time’ is transformed properly. By moving from one time domain to another, one may deform certain time‐varying data to non‐time‐varying data. With these non‐time‐varying data on the deformed timescale, one may use traditional tools to do parameter estimation and forecasts. The obtained results then can be transformed back to the original timescale. For datasets with an underlying discrete Euler process, the sample M‐spectrum and the spectra estimator of a Euler model (i.e., EAR spectral) are used to detect cycles of a Euler process. Beam response and whale data are used to demonstrate the usefulness of a Euler model. Copyright © 2008 John Wiley & Sons, Ltd.     

长三角地区常用遥感降水产品质量评估

长三角地区是中国经济最发达地区之一,选定较好的卫星降水产品是进行科学防灾减灾的重要环节.基于地面气象站降水实测数据,采用7种指标对目前中外常用遥感降水产品热带降水任务卫星(tropical rainfall measurement mission,TRMM)、气候预测中心校正产品(climate prediction ...     

冲击荷载下含裂纹缺口三点弯动态断裂实验

为研究缺口大小对含裂纹缺口构件动态断裂的影响,采用动态光弹性实验方法,对含裂纹缺口试件进行了冲击实验.基于冲击断裂过程中试件的等差条纹变化图片和动态应变仪采集的应变数据,分析了冲击荷载下裂纹尖端的动态应力强度因子、裂纹扩展速度和锤头应变的变化规律.结果表明:不同缺口角度试件受到冲击荷载后,应力强度因子的变化随时间变化的...     

不同厚度三点弯曲梁的裂纹扩展动态焦散实验

采用动态焦散线实验方法,对冲击作用下不同厚度的三点弯曲梁进行了研究,分析了厚度对其动态断裂过程的影响.结果表明:不同厚度三点弯曲梁在动态冲击实验中,预制裂纹起裂时间和扩展时间受到试件厚度的影响.厚度越大,起裂越慢,扩展时间越长;试件起裂后,不同厚度下裂尖的扩展速度和动态应力强度因子值随时间的变化曲线均呈现先快速上升后波...     

水泥浆凝结硬化时内部结构与超声频谱的变化

论述了超声脉冲穿过硬化过程中的水泥浆时超声频谱的变化,并分析了声速,频率幅值与水泥浆期龄之间的关系。实验证明超声频率是观察硬化水泥浆早期结构的变化及测定水泥凝结时间的有效方法。     

增量谐波平衡法用于输液管的非线性振动分析

将增量谐波平衡法推广至分析输液管的非线性振动问题 ,研究了输液管的幅频曲线特性 .数值结果显示输液管由于流体的作用将产生振幅突变这一不稳定现象 ,并给出输液管的周期解 .同时还研究了流速和管液质量比对系统振动特性的影响     

甘蓝型油菜BnHY5基因的表达模式及非生物胁迫响应分析

为探究甘蓝型油菜中HY5的表达情况,首先通过甘蓝型油菜基因组数据分析预测HY5及其同源基因HYH(HY5-Homologous),克隆获得了四个HY5(命名为BnHY5)以及三个HYH(命名为BnHYH)重复基因全长cDNA序列.其次,对BnHY5进行了蛋白结构预测、理化性质分析,研究结果表明:BnHY5蛋白为不稳定、亲水性蛋白,主要结构域为亮氨酸拉链.最后,探究了甘蓝型油菜中该基因的表达情况,用荧光定量PCR分析了BnHY5重复基因表达模式和响应非生物胁迫的情况,BnHY5四个基因中,BnHY5-2的表达水平最高,BnHY5-1、BnHY5-2不存在组织表达差异且表达水平高于BnHY5-3、BnHY5-4.BnHY5基因不仅响应高温、低温、镉、高盐非生物胁迫,而且参与ABA和GA_3激素信号响应,说明BnHY5在逆境胁迫中有重要作用.此外BnHY5重复基因在非生物胁迫下的表达模式发生改变,BnHY5四个基因的表达占比与不同类型胁迫处理相关,存在表达差异.