Mechanisms of Hyperhomocysteinemia Induced Skeletal Muscle Myopathy after Ischemia in the CBS?/+ Mouse Model

Although hyperhomocysteinemia (HHcy) elicits lower than normal body weights and skeletal muscle weakness, the mechanisms remain unclear. Despite the fact that HHcy-mediated enhancement in ROS and consequent damage to regulators of different cellular processes is relatively well established in other organs, the nature of such events is unknown in skeletal muscles. Previously, we reported that HHcy attenuation of PGC-1α and HIF-1α levels enhanced the likelihood of muscle atrophy and declined function after ischemia. In the current study, we examined muscle levels of homocysteine (Hcy) metabolizing enzymes, anti-oxidant capacity and focused on protein modifications that might compromise PGC-1α function during ischemic angiogenesis. Although skeletal muscles express the key enzyme (MTHFR) that participates in re-methylation of Hcy into methionine, lack of trans-sulfuration enzymes (CBS and CSE) make skeletal muscles more susceptible to the HHcy-induced myopathy. Our study indicates that elevated Hcy levels in the CBS^−/+ mouse skeletal muscles caused diminished anti-oxidant capacity and contributed to enhanced total protein as well as PGC-1α specific nitrotyrosylation after ischemia. Furthermore, in the presence of NO donor SNP, either homocysteine (Hcy) or its cyclized version, Hcy thiolactone, not only increased PGC-1α specific protein nitrotyrosylation but also reduced its association with PPARγ in C2C12 cells. Altogether these results suggest that HHcy exerts its myopathic effects via reduction of the PGC-1/PPARγ axis after ischemia.     

Comparison of different extraction methods for the extraction of major bioactive flavonoid compounds from spearmint (Mentha spicata L.) leaves

Different bioactive flavonoid compounds including catechin, epicatechin, rutin, myricetin, luteolin, apigenin and naringenin were obtained from spearmint (Mentha spicata L.) leaves by using conventional soxhlet extraction (CSE) and supercritical carbon dioxide (SC-CO₂) extraction at different extraction schemes and parameters. The effect of different parameters such as temperature (40, 50 and 60 °C), pressure (100, 200 and 300 bar) and dynamic extraction time (30, 60 and 90 min) on the supercritical carbon dioxide (SC-CO₂) extraction of spearmint flavonoids was investigated using full factorial arrangement in a completely randomized design (CRD). The extracts of spearmint leaves obtained by CSE and optimal SC-CO₂ extraction conditions were further analyzed by high performance liquid chromatography (HPLC) to identify and quantify major bioactive flavonoid compounds profile. Comparable results were obtained by optimum SC-CO₂ extraction condition (60 °C, 200 bar, 60 min) and 70% ethanol soxhlet extraction. As revealed by the results, soxhlet extraction had a higher crude extract yield (257.67 mg/g) comparing to the SC-CO₂ extraction (60.57 mg/g). Supercritical carbon dioxide extract (optimum condition) was found to have more main flavonoid compounds (seven bioactive flavonoids) with high concentration comparing to the 70% ethanol soxhlet extraction (five bioactive flavonoids). Therefore, SC-CO₂ extraction is considered as an alternative process compared to the CSE for obtaining the bioactive flavonoid compounds with high concentration from spearmint leaves.     

基于元码段可重构的事物编码系统研究

为了适应复杂多变的编码规则,统一和共享码段信息资源,提出了元码段的概念及其细分方法,分析了元码段的类型。阐述了基于元码段细分和元码段重构的混合式编码规则定义方法,分析了基于该方法的编码系统功能。对元码段实现方法、数据库设计、PDM系统集成模型等关键技术进行了研究。实例表明该方法支持定义复杂的编码规则,重用码段数据,可降低编码系统开发和维护成本。     

基于Web的协作支持环境的研究与实现

提出的基于Web的协作支持环境（CSE），采用非透明事件广播类的同步协作模型，有效地解决了茯享屏幕类同步协作模型所存在的问题，可以很好地应用于Internet环境。对基于Web的协作支持环境的总体结构及各个模块的功能进行了详细讨论，并介绍了该系统的开发环境和实现方法。     

走出“长效”的误区——兼与《阴极保护和参比电极》一文的作者讨论

在防腐和阴极保护的技术和管理中存在一些认识模糊甚至错误的东西得不到及时纠正，使用多年的长效参比电极就是一例。认真分析发现，它们无论在理论上还是规范上都是不合格的，CSE—x3新长效参比电极的出现解决了这一问题。     

THE BATTLE OF THE SEALS

This article is primarily about the seals of the National Security Agency (NSA) and its Central Security Service (CSS). Specifically, this article provides, for the first time, a copy of the NSA seal that preceded the current one, a copy of the CSS seal, and their respective histories. A brief biography of the current CSS Deputy Chief and a very brief history about CSS itself is also provided. A number of references are made to James Bamford's two books: Body of Secrets (May 2001) and The Puzzle Palace (1982). My intention is not to nitpick his works. Rather, I simply wish to clarify points that readers may find confusing, especially since he is the world's leading authority on NSA. I not only admire Bamford's investigative journalism, but also strive toward the very high standard that he has set.     

卷烟添加木犀草素与黄芩苷混合物对细胞损伤的减害作用研究

将木犀草素、黄芩苷混合物加入卷烟制成样品卷烟,研究其在卷烟烟气中对人肺泡上皮细胞损伤的影响。用不同浓度卷烟烟气提取物(cigarette smoke extract,CSE)刺激人肺泡上皮细胞A549,采用MTT实验检测细胞存活率,彗星实验观察DNA损伤,荧光法测定细胞内活性氧(reactive oxygen species,ROS)含量。结果表明,与对照卷烟比较,样品卷烟组细胞存活率升高,细胞内活性氧(ROS)彗星尾长、尾部DNA含量、尾距、Olive尾距均小于对照卷烟组。因此,添加木犀草素与黄芩苷混合物的特制卷烟烟气对细胞的损伤较少,产生较少ROS,减少一定的DNA损伤,对细胞毒性有一定的减害作用。     

一种新的协作式搜索引擎的设计与实现

该文提出了一种分布式信息检索系统,叫作协作式搜索引擎(CSE),它是由多个相互协作的本地元搜索引擎构成的。每一个本地搜索引擎都有它自己的索引数据库,能够很快地进行更新。CSE通过基于站点选择搜索和对Web文档计分等方法来减少通信延迟、缩短收集时间,实现快速收集、及时更新和定位准确,从而克服了目前的搜索引擎更新周期太长的缺点。     

由栅格等高线快速建立DEM的CSE法

介绍了一种由等高线版图通过图像处理,准确、高效建立DEM的CSE（Color Substitute Elevation,颜色替换高程）法,在分析其算法精度的基础上,说明该方法相对于传统DEM建立方法的优越性。