MPEG—4标准视频编码初论

MPEG－4视频部分（ISO／IEC 14496－3）是MPEG－4标准核心内容之一，它既提供了传统的基于帧的编码方法也提供了基于视频对象的编码方法，为高效压缩与基于内容的交互提供了坚实的基础，文章对MPEG－4标准视频编码部分做了详细的描述，并对MPEG－4视频的应用做了简要介绍。     

新一代边缘网设备——SDH多业务平台

SDH多业务平台（Multi-Service Transport Platfrom)，简称MSTP，利用SDH的技术支持传统电路与新兴数据业务，构成功能强大的综合接入平台，满足用户不同的需求，内置数据交换能力的MSTP可以利用统计复用特性大提高传输效率，同时在传输过程中实现分布式的交换，减少局域或中心站的端口数。     

变电站绝缘在线监测系统

介绍了一种变电站绝缘实时监测系统的组成、功能和特点,它可防止事故发生,并为计划检修向状态检修过渡提供依据。     

基于Petri网络计及警报信息时间特性故障诊断模型

电力系统发生故障时，警报信息具有时间特性，这一特性直接影响故障诊断结果的准确性和诊断速度，提出了一种计及报警信息时间特性故障树Petri网故障诊断模型和故障树表示方法，利用Petri网络描述了故障征兆与故障的关系，用故障树矩阵运算进行推理，比传统专家系统大大减少了诊断时间，提高了准确度，最后通过测试实例验证此故障诊断模型方法的快速，准确性。     

电站蒸汽系统建模与分析

介绍了一种电站主蒸汽系统与汽轮机组时仿真模型。该模型基于物理基本定律，并适用于电站从空载到满载的运行状态，考虑了可压缩蒸汽的流动，汽轮机中实际的膨胀过程，调节级和末级运行条件改变下效率的变化，以及管道破裂等因素的影响，仿真结果表明，该模型能应用于化石燃料机组及沸水堆，压水堆原子能电站机组，且在正常运行状态和异常运行状态条件下都适用，仿真结果还表明该模型稳定精度高，暂态性能好，该模型可为新一代机组的研制提供良好的试验环境。     

消除线路过载现象的移相变压器选址问题研究

在分析线路过载现象产生原因的基础上，对移相变压器的选址问题进行了研究，提出了能反映移相变压器调控效果与安装位置有关的绝对指标和相对指标的概念以及选址方法。对某省实际电力系统典型运行方式下的移相变压器进行了选址分析，结果表明，应用文中所提的指标和方法可以准确地确定移相变压器的安装位置。     

Differential binding of tropane-based photoaffinity ligands on the dopamine transporter

Benztropine and its analogs are tropane ring-containing dopamine uptake inhibitors that produce behavioral effects markedly different from cocaine and other dopamine transporter blockers. We investigated the benztropine binding site on dopamine transporters by covalently attaching a benztropine-based photoaffinity ligand, [125I]N-[n-butyl-4-(4"'-azido-3"'-iodophenyl)]-4', 4"-difluoro-3alpha-(diphenylmethoxy)tropane ([125I]GA II 34), to the protein, followed by proteolytic and immunological peptide mapping. The maps were compared with those obtained for dopamine transporters photoaffinity labeled with a GBR 12935 analog, [125I]1-[2-(diphenylmethoxy)ethyl]-4-[2-(4-azido-3-iodophenyl)ethy l]p iperazine ([125I]DEEP), and a cocaine analog, [125I]3beta-(p-chlorophenyl)tropane-2beta-carboxylic acid, 4'-azido-3'-iodophenylethyl ester ([125I]RTI 82), which have been shown previously to interact with different regions of the primary sequence of the protein. [125I]GA II 34 became incorporated in a membrane-bound, 14 kDa fragment predicted to contain transmembrane domains 1 and 2. This is the same region of the protein that binds [125I]DEEP, whereas the binding site for [125I]RTI 82 occurs closer to the C terminal in a domain containing transmembrane helices 4-7. Thus, although benztropine and cocaine both contain tropane rings, their binding sites are distinct, suggesting that dopamine transport inhibition may occur by different mechanisms. These results support previously derived structure-activity relationships suggesting that benztropine and cocaine analogs bind to different domains on the dopamine transporter. These differing molecular interactions may lead to the distinctive behavioral profiles of these compounds in animal models of drug abuse and indicate promise for the development of benztropine-based molecules for cocaine substitution therapies.     

石膏发泡的研究

以建筑石膏、水泥为原料，采用复合发泡剂发泡制成墙体材料。研究表明，复合发泡剂可以对石膏浆体起到良好的发泡作用。     

Repeated dosing with the peroxisome proliferator clofibrate decreases the toxicity of model hepatotoxic agents in male mice

Pretreatment of mice with clofibrate (CFB) has been shown to protect against acetaminophen (APAP) hepatotoxicity. To determine if pretreatment with CFB prevents the toxicity of other model hepatotoxicants, male C57BL6J or CD-1 mice received 500 mg CFB/kg, i.p., daily for 10 days, and then were challenged with either 250 mg bromobenzene (BrB)/kg, 0.025 ml carbon tetrachloride (CCl4)/kg or 0.5 ml chloroform (CHCl3)/kg. Liver and kidney injury was assessed by plasma sorbitol dehydrogenase activity (SDH) and blood urea nitrogen (BUN), respectively and histopathology. Challenge with BrB significantly elevated plasma SDH activity in C57Bl6J mice. This was prevented in CFB pretreated mice receiving the same dose of BrB. Changes in BUN were not detected in either group of BrB treated mice. Similarly, pretreatment of male CD-1 mice with CFB significantly reduced CCl4-induced elevation in plasma SDH activity, with no BUN elevation detected in either group. CFB pretreatment also diminished elevation in plasma SDH activity produced by CHCl3 in CD-1 mice, while BUN was significantly elevated in both groups, indicating that CFB did not protect against CHCl3-induced nephrotoxicity. Histopathological examination of liver and kidney sections confirmed these results. This study shows that mice pretreated with CFB were protected from toxicity at 24 h after challenge with other model hepatotoxic agents besides APAP.     

The effectiveness of early endoscopy for upper gastrointestinal hemorrhage: a community-based analysis

OBJECTIVES: The effectiveness of upper endoscopy in unselected patients with upper gastrointestinal hemorrhage has not been well studied. This study was undertaken to identify factors associated with the performance of early endoscopy (ie, within 1 day of hospitalization) and, after adjusting for these factors, to determine associations between early endoscopy and in-hospital mortality, length of stay, and performance of surgery. METHODS: Subjects in this observational cohort study were 3,801 consecutive admissions with upper gastrointestinal hemorrhage to 30 hospitals in a large metropolitan region. Demographic and clinical data were abstracted from hospital records. A multivariable model based on factors that potentially could relate to the decision to perform endoscopy was developed to determine the propensity (0 to 100%) for early endoscopy in each patient. RESULTS: Early endoscopy was performed in 2,240 patients (59%), and although it was not associated with mortality after adjusting for severity of illness among all patients, it was associated with a higher risk of death for patients in the lowest propensity group. Early endoscopy was associated with a lower likelihood of upper gastrointestinal surgery in all patients and in the two highest propensity groups and with a shorter length of stay in the entire cohort and in all subgroups. CONCLUSIONS: In the absence of specific contraindications, early endoscopy should be considered because of associated reductions in length of stay and surgical intervention. Further studies are needed to identify subgroups in whom the procedure may be associated with adverse effects on survival.