Rocket UV flash spectra from the solar eclipse of March 7, 1970

Flash spectra of the total solar eclipse throughout all its phases have been obtained in the extreme ultraviolet for the first time.     

Induction of dendritic spines by an extracellular domain of AMPA receptor subunit GluR2

Synaptic transmission from excitatory nerve cells in the mammalian brain is largely mediated by AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid)-type glutamate receptors located at the surface of dendritic spines. The abundance of postsynaptic AMPA receptors correlates with the size of the synapse and the dimensions of the dendritic spine head. Moreover, long-term potentiation is associated with the formation of dendritic spines as well as synaptic delivery of AMPA receptors. The molecular mechanisms that coordinate AMPA receptor delivery and spine morphogenesis are unknown. Here we show that overexpression of the glutamate receptor 2 (GluR2) subunit of AMPA receptors increases spine size and density in hippocampal neurons, and more remarkably, induces spine formation in GABA-releasing interneurons that normally lack spines. The extracellular N-terminal domain (NTD) of GluR2 is responsible for this effect, and heterologous fusion proteins of the NTD of GluR2 inhibit spine morphogenesis. We propose that the NTD of GluR2 functions at the cell surface as part of a receptor-ligand interaction that is important for spine growth and/or stability.     

The voltage dependence of NADPH oxidase reveals why phagocytes need proton channels

The enzyme NADPH oxidase in phagocytes is important in the body's defence against microbes: it produces superoxide anions (O2-, precursors to bactericidal reactive oxygen species). Electrons move from intracellular NADPH, across a chain comprising FAD (flavin adenine dinucleotide) and two haems, to reduce extracellular O2 to O2-. NADPH oxidase is electrogenic, generating electron current (I(e)) that is measurable under voltage-clamp conditions. Here we report the complete current-voltage relationship of NADPH oxidase, the first such measurement of a plasma membrane electron transporter. We find that I(e) is voltage-independent from -100 mV to >0 mV, but is steeply inhibited by further depolarization, and is abolished at about +190 mV. It was proposed that H+ efflux mediated by voltage-gated proton channels compensates I(e), because Zn2+ and Cd2+ inhibit both H+ currents and O2- production. Here we show that COS-7 cells transfected with four NADPH oxidase components, but lacking H+ channels, produce O2- in the presence of Zn2+ concentrations that inhibit O2- production in neutrophils and eosinophils. Zn2+ does not inhibit NADPH oxidase directly, but through effects on H+ channels. H+ channels optimize NADPH oxidase function by preventing membrane depolarization to inhibitory voltages.     

ARSACS, a spastic ataxia common in northeastern Québec, is caused by mutations in a new gene encoding an 11.5-kb ORF

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS or SACS) is an early onset neurodegenerative disease with high prevalence (carrier frequency 1/22) in the Charlevoix-Saguenay-Lac-Saint-Jean (CSLSJ) region of Quebec. We previously mapped the gene responsible for ARSACS to chromosome 13q11 and identified two ancestral haplotypes. Here we report the cloning of this gene, SACS, which encodes the protein sacsin. The ORF of SACS is 11,487 bp and is encoded by a single gigantic exon spanning 12,794 bp. This exon is the largest to be identified in any vertebrate organism. The ORF is conserved in human and mouse. The putative protein contains three large segments with sequence similarity to each other and to the predicted protein of an Arabidopsis thaliana ORF. The presence of heat-shock domains suggests a function for sacsin in chaperone-mediated protein folding. SACS is expressed in a variety of tissues, including the central nervous system. We identified two SACSmutations in ARSACS families that lead to protein truncation, consistent with haplotype analysis.     

双复合Poisson风险模型的赤字尾概率

研究双复合Poisson过程的风险模型,得到了关于赤字尾概率的函数型不等式,并且作为它的应用,得到了一些指数型上界估计,使得某些已有结果得到推广.     

射频PECVD方法生长含氢非晶碳膜的结构及摩擦学性能

利用射频等离子体增强化学气相沉积技术在不锈钢表面制备了含氢非晶碳膜.采用Raman光谱、红外光谱、X射线光电子能谱和原子力显微镜等研究了薄膜的微观结构和表面形貌,在栓盘摩擦磨损试验机上考察了薄膜在不同载荷与滑动速度下的摩擦学性能.结果表明:所制备的含氢非晶碳膜具有典型的类金刚石结构特征,薄膜均匀、致密,表面粗糙度小;薄膜与不锈钢球对磨时显示出良好的抗磨减摩性能;薄膜的抗磨减摩性能同对磨件表面上形成的转移膜以及摩擦过程中薄膜结构的石墨化相关.     

翻转课堂下无机非金属材料专业课程教学与考核方法研究

探索了翻转课堂模式下无机非金属材料专业课程的教学与考核方法.设计了10 min线上微课+30 min课堂小组讨论+20 min师生互动总结的教学方法.成绩考核注重过程,期中考试成绩占20%,期末考试成绩占40%,平时考核成绩占40%.实践证明,该教学和考核方法有助于鼓励学生自主学习,可提高教学质量和学生的综合素质.     

基于北斗定位导航系统的士兵状态监视与指挥控制系统

战场救护中,及时发现士兵伤情并迅速找到伤员是挽救伤员的重要条件,因此,对受伤士兵的定位与获取需救护伤员的准确个人信息对于救护的有效性具有非常重要的意义。基于北斗卫星的定位导航系统设计战场士兵信息采集与指挥控制系统,利用我国自主研发的北斗卫星导航定位通信系统对战场士兵进行定位,通过由基于蓝牙的士兵状态监视终端对士兵生理状态参数进行连续监测,当发现士兵伤情时实时由通信终端向指挥控制中心传递伤员个人信息和生理状态参数,指挥中心接收伤员数据后,通过GIS系统、根据地形等信息可实时规划救援路线和救援方案,以实现对伤员的及时救治。分析了北斗卫星导航系统的功能与特点,介绍了士兵信息采集与指挥控制系统的组成及功能,详细阐述了士兵信息采集终端的设计、生命体征信息监测方法、指挥控制系统的组成与功能以及地理信息系统(GIS)设计。     

铝合金凝固晶粒尺寸的人工神经网络研究

建立了强脉冲电磁场作用下铝合金凝固组织晶粒尺寸的人工神经网络BP算法模型。用该模型进行的模拟结果和实验数据吻合得较好。研究表明，用这一方法可对脉冲电磁场作用下的凝固组织晶粒尺寸进行预测，为优化实验设计提供了简便实用的方法和手段。