基于P2P的流媒体VoD技术初探

随着网络通信技术的发展和宽带使用的普及,互联网上的信息逐渐由数据量小的单纯文字转变为包括音视频的多媒体数据及大文件等,前者催生了流媒体Vod（~点播）技术,而后者则催生了P2P技术。传统的流媒体技术扩展性较差,而其陆续提出的基于C／S模式的组播和CDN模式也都有比较严重的不足,所以,P2P技术与流媒体VoD相结合是一个重要研究方向。     

论安徽地方戏“亳州二夹弦”的艺术取向

安徽地方戏＂亳州二夹弦＂崇尚浓郁的地方特色和揭示人类共有的心灵意识,追求浓郁的乡土气息和生活情趣,注重透过中原文化的表层去揭示华夏传统文化的内核精神与人文品质,以表现自由、鲜活、强盛的生命力。     

膜片钳吉欧封接的电极内微压力控制系统

介绍了一种膜片钳实验用的电极内气动微压力控制系统,使用该系统在膜片钳实验中对大鼠胰腺β细胞进行封接实验,给电极内施加0．5kPa正压入液时,电极电阻平均为5．04MΩ;贴附细胞膜表面后电极电阻均值为;5．44MΩ将电极内压力从正压转变为-3．5kPa左右负压,并将微玻璃电极内电位设为-40mV到-90mV之间,结果显示平均封接电阻达到2．98GΩ．将此结果和人工封接结果进行对比,两者没有显著性差异。     

XH714加工中心的夹刀机构

文章以XH714立式加工中心为例 ,简要介绍了加工中心的夹刀机构 ,包括夹紧力、动作时间和接触应力的计算 ,从而对加工中心的夹刀机构得到认识和了解     

结构相似度索引耦合最优稀疏表示的大规模损坏图像动态修复

当前的图像修复算法在处理小面积损坏图像时,可取得较佳的视觉质量;但难以用于高对比度边缘和高频分量的大面积损坏图像的修复,存在明显的模糊效应与块效应,使得修复质量较差。对此,提出了结构相似度索引耦合优化稀疏表示的大规模损坏图像动态修复机制。基于数据度与置信度构造图像块先验模型,提取损坏图像的已知块;再引入K-SVD算法和拉格朗日乘数机制,构造最优字典矩阵,优化稀疏表示,以重构目标图像损坏区域;并设计结构相似度索引与动态更新机制,估算稀疏表示系数,并动态更新字典矩阵,输出修复图像。最后测试了其机制性能。结果表明:与当前图像修复算法相比,在大规模损坏图像与高对比度边缘图像修复中,具有更好的修复效果、更高的相似度,显著消除了模糊效应与块效应。     

2-APB对Wistar大鼠脑微动脉平滑肌细胞间缝隙连接的抑制作用

为探讨2-APB对Wistar大鼠脑微动脉平滑肌细胞间缝隙连接的作用。采用全细胞膜片钳技术,观察2-APB对Wistar大鼠脑微动脉段上平滑肌细胞膜电容(Cinput)、膜电导(Ginput)和膜电阻(Rinput)的影响。结果显示,应用2-APB后Wistar大鼠脑动脉段平滑肌细胞的Cinput、Ginput减小或Rinput增大。当2-APB浓度≥100μmol/L时Wistar大鼠脑微动脉段上平滑肌细胞的Cinput、Ginput分别从81±18 pF和3.5±0.43 nS降至10.5±1.3pF(n=7,P0.01)和0.35±0.03nS(n=7,P0.01),这与单个平滑肌细胞十分接近。由此可知,2-APB可以浓度依赖性的抑制Wistar大鼠脑微动脉平滑肌细胞间缝隙连接。     

Calyculin a increases voltage-dependent inward current in,smooth muscle cells isolated from guinea pig taenia coli

The effects of a potent phosphatase inhibitor, calyculin A (CL-A), on inward currents in guinea pig taenia coli smooth muscle cells were examined. CL-A increased the inward current, and this effect of CL-A was inhibited by a protein kinase C inhibitor, H-7, and by nifedipine. Phorbol 12,13-dibutyrate, an activator of protein kinase C, also increased the inward current and this effect was antagonized by H-7. These results suggest that in guinea pig taenia coli smooth muscle cells CL-A may facilitate the opening of thel-type Ca²⁺ channels through the protein kinase C-dependent phosphorylation system.     

Two serotonin-sensitive potassium channels in the identified heart excitatory neurone of the African giant snail,Achatina fulica Fèrussac

Summary By the patch clamp experiments, two serotonin-sensitive K⁺ channels (SL-channel and SS-channel) were demonstrated in the identified heart excitatory neurone (PON) of the African giant snail,Achatina fulica Fèrussac. The activities of both channels could be recorded in the steady state and those activities disappeared on application of 5-HT.     

Patch and whole-cell voltage clamp of single mammalian visceral and vascular smooth muscle cells

Summary Dispersal of the constituent cells of mammalian visceral and vascular smooth muscles has permitted recordings both of membrane currents under whole-cell voltage clamp, and of currents through single ionic channels using the patch-clamp technique. A rectangular depolarizing step applied to a single cell under voltage clamp yielded a net inward current followed by a net outward current in normal physiological solution. In isolated, inside-out patches of cell membrane a calcium- and potential-sensitive K channel (100 pS conductance) and a calcium-insensitive, potential-sensitive K⁺ channel (50 pS conductance) with slow kinetics have so far been identified and characterized.