Mitochondrial BNIP3 upregulation precedes endonuclease G translocation in hippocampal neuronal death following oxygen-glucose deprivation

Background  

Caspase-independent apoptotic pathways are suggested as a mechanism for the delayed neuronal death following ischemic insult. However, the underlying signalling mechanisms are largely unknown. Recent studies imply the involvement of several mitochondrial proteins, including endonuclease G (EndoG) and Bcl-2/adenovirus E1B 19 kDa-interacting protein (BNIP3), in the pathway of non-neuronal cells.     

金属有机物化学气相沉积法生长Ga2(1-χ)In2χO3薄膜的结构及光电性能研究

采用金属有机物化学气相沉积(MOCVD)法在蓝宝石(0001)衬底上制备出了Ga2(1-χ)In2χO3(χ=0.1-0.9)薄膜,研究了薄膜的结构、电学和光学特性以及退火处理对薄膜性质的影响.测量结果表明:当In组分χ=0.2时,样品为单斜β-Ga2O3,结构;χ=0.5的样品,薄膜呈现非晶结构,退火处理后薄膜结构得到明显的改善,由非晶结构转变为具有(222)单一取向的立方In2O3结构;对于χ=0.8,薄膜为立方In2O3,结构,退火后薄膜的晶体质量得到提高.在可见光区薄膜本身的透过率均达到了85%以上,带隙宽度随样品中Ga含量的改变在3.76-4.43 eV之间变化,且经退火处理后带隙宽度明显增大.     

多面转镜激光器扫频光学相干层析成像系统的全光谱重采样方法

在多面转镜激光器扫频光学相干层析成像系统中,激光器存在着输出光谱错位与扫频范围波动的问题.目前的重采样方法中,普遍利用互相关运算校正光谱错位,并进行大范围的截取,保证扫频范围的一致性,但这会导致成像信噪比与分辨率的降低.本文用马赫-曾德尔干涉仪(MZI)采集到的干涉信号对扫频范围波动的问题进行了详细的测量与分析,其中干涉信号的解缠相位曲线的非随机性和平行性,表明该类激光器输出光谱的波长分布具备一致性.在此基础上,提出了一种用最长扫频范围的MZI干涉信号,对样品干涉信号进行时域光谱对齐、然后进行一对多插值的重采样方法.实验与分析表明,该方法利用了所有的光谱信号,保证了样品干涉信号的能量利用率,能有效提高图像的信噪比与分辨率.     

The nonlinear theory of slow-wave electron cyclotron masers with inclusion of the beam velocity spread

The nonlinear theory of slow-wave electron cyclotron masers (ECM) with an initially straight electron beam is developed. The evolution equation of the nonlinear beam electron energy is derived. The numerical studies of the slow-wave ECM efficiency with inclusion of Gaussian beam velocity spread are presented. It is shown that the velocity spread reduces the interaction efficiency.     

应用导数荧光光谱和概率神经网络鉴别合成色素

实验测量了食品色素胭脂红、苋菜红、诱惑红和工业色素苏丹红Ⅳ溶液分别在波长为300,400,440和380 nm的光激发下产生的荧光光谱.对这4种红色素的各8个溶液样本选取60个发射波长值所对应的荧光强度作为网络特征参数,训练、建立概率神经网络.据此,对32个色素溶液样本进行种类识别.为解决原始荧光光谱重叠造成识别准确率不高的问题,应用导数荧光光谱,将二阶导数光谱数据作为网络特征参数,建立网络,进行识别,识别准确率达100%.由此,提出了应用二阶导数荧光光谱结合概率神经网络对合成色素方便、快捷、准确地进行种     

Effect of solvent on directional drift in Brownian motion of particle/molecule with broken symmetry

The directional drifting of particles/molecules with broken symmetry has received increasing attention. Through molecular dynamics simulations, we investigate the effects of various solvents on the time-dependent directional drifting of a particle with broken symmetry. Our simulations show that the distance of directional drift of the asymmetrical particle is reduced while the ratio of the drift to the mean displacement of the particle is enhanced with increasing mass, size, and interaction strength of the solvent atoms in a short time range. Among the parameters considered, solvent atom size is a particularly influential factor for enhancing the directional drift of asymmetrical particles, while the effects of the interaction strength and the mass of the solvent atoms are relatively weaker. These findings are of great importance to the understanding and control of the Brownian motion of particles in various physical, chemical, and biological processes within finite time spans.     

A novel carbon source coated on C-LiFePO<Subscript>4</Subscript> as a cathode material for lithium-ion batteries

The poor electronic conductivity and low lithium-ion diffusion are the two major obstacles to the largely commercial application of LiFePO₄ cathode material in power batteries. In order to improve the defects of LiFePO₄, a novel carbon source polyacrylonitrile (PAN), which would form the hierarchical porous structure after carbonization, is fabricated and used. This work comes up with a simple and facile carbothermal reduction method to prepare porous-carbon-coated LiFePO₄ (C-LiFePO₄-PC) composite and to study the effect of carbon-coated temperature on ameliorating the electrochemical performance. The obtained C-LiFePO₄-PC composite shows a high initial discharge capacity of 164.1 mA h g^?1 at 0.1 C and good cycling stability as well as excellent rate capacity (49.0 mA h g^?1 at 50 C). The most possible factors that improve the electrochemical performance could be related to the enhancement of electronic conductivity and the existence of porous carbon layers. In a word, the C-LiFePO₄-PC material would become an excellent candidate for application in the fields of lithium-ion batteries.     

The effect of basilar-membrane nonlinearity on the shapes of masking period patterns in normal and impaired hearing

Masking period patterns (MPPs) were measured in listeners with normal and impaired hearing using amplitude-modulated tonal maskers and short tonal probes. The frequency of the masker was either the same as the frequency of the probe (on-frequency masking) or was one octave below the frequency of the probe (off-frequency masking). In experiment 1, MPPs were measured for listeners with normal hearing using different masker levels. Carrier frequencies of 3 and 6 kHz were used for the masker. The probe had a frequency of 6 kHz. For all masker levels, the off-frequency MPPs exhibited deeper and longer valleys compared with the on-frequency MPPs. Hearing-impaired listeners were tested in experiment 2. For some hearing-impaired subjects, masker frequencies of 1.5 kHz and 3 kHz were paired with a probe frequency of 3 kHz. MPPs measured for listeners with hearing loss had similar shapes for on- and off-frequency maskers. It was hypothesized that the shapes of MPPs reflect nonlinear processing at the level of the basilar membrane in normal hearing and more linear processing in impaired hearing. A model assuming different cochlear gains for normal versus impaired hearing and similar parameters of the temporal integrator for both groups of listeners successfully predicted the MPPs.     

合肥国家同步辐射光源软X射线束空间相干性实验研究

本文从实验角度对合肥国家同步辐射实验室软X射线束的空间相干性进行了研究.利用放置在物面上的高分辨正性光刻胶,记录了中心波长为3.2nm的波带片和针孔直径为30μm组合的光场分布(光斑),获得相应条件下的爱里斑及空间相干直径实验数据;完成了一个双缝干涉实验.所得的这些结果与理论计算相一致.     

垂直加热管外自由降膜流的破断特性

在较宽液膜雷诺数和进口温度范围内对垂直加热管外自由降膜流破断特性进行了实验研究。应用热物理学相似分析的方法整理实验数据，给出新的破断准则数综合关系式，并与１９９３年发表的另一些作者的结果作了比较。实验参数的变化范围如下：ｔｉｎ＝２０～９０℃，最大液膜雷诺数Ｒｅ为１．２１×１０４，最大热流密度达１．３９×１０５ｗ／ｍ２。