影像设备电路板测试与故障诊断之系统实现

大型医学影像设备是医院中的贵重设备,其中不少进口设备的维护修理的技术难度较高,医院每年花费在医学影像设备上的维护修理费是非常之大。本文从建立国内的维修力量着眼,研讨医学影像设备维修方法。     

猴头菌和金针菇漆酶对不同染料的降解

利用漆酶(laccase)处理染料废水是近年来研究的热点.本研究以猴头菌Hericium erinaceus和金针菇Flammulina filiformis的发酵液为试验材料,通过硫酸铵沉淀、离子交换层析和超滤等方法,对发酵液中的漆酶进行了初步的分离纯化,然后分别研究了两种初提纯漆酶及其与小分子介体组成的漆酶介体系统...     

扁玉螺中枢神经系统解剖及显微结构观察

对扁玉螺(Neverita didyma)中枢神经系统的大体解剖和显微结构进行了初步研究。结果表明,扁玉螺中枢神经系统包括一对口球神经节、一对脑神经节、一对侧神经节、一对足神经节及一个脏神经节。各神经节均由神经节被膜、胞体区及中央纤维网三部分组成。左右脑神经节之间和左右足神经节之间的联合以及脑-侧、脑-足和侧-足神经节之间的连索均较短。足神经节有明显的分区现象。     

同翅类昆虫的雄性生殖系统及精子发生(昆虫纲:半翅目)

本文比较了同翅类昆虫雄性生殖系统的结构、减数分裂期间染色体的行为和精子尾部的超微结构。研究表明蜡蝉总科和异翅类的精巢具有被膜,而蝉总科、叶蝉总科、沫蝉总科、角蝉总科、木虱总科、蚜总科、粉虱总科和蚧总科的精巢均不具有被膜。也可以根据精巢小叶的形状将精巢分为三类,蝉总科、叶蝉总科、沫蝉总科、角蝉总科、蚜总科和粉虱总科的精巢小叶为球形,蜡蝉总科、木虱总科和蚧总科的精巢小叶为管状,而异翅类的精巢小叶为片层状。减数分裂可以被分为5类:①蝉型(Cicadoidtype);②蜡蝉型(Fulgoroidtype);③木虱型(Psyloidtype);④蚜型(Aphidoidtype);⑤粉虱型(Aleyrodoidtype)和⑥蚧型(Coccoidtype),至少具有四个类群的减数分裂前期I具有弥散期,它们是:木虱总科、蜡蝉总科、蚧总科和异翅类。除粉虱总科和蚧总科的精子尾部退化以外,其余种类的精子鞭毛均具有典型的9 9 2轴丝结构。     

人机共融的主动型下肢假肢分层控制策略探讨

为研究当前主动型下肢假肢控制问题的解决策略,提出了主动型下肢假肢设计和分类的通用控制框架,包括3个分层结构:上层控制器、中层控制器、底层控制器。其中,上层控制器感知运动意图;中层控制器将运动意图转换为预期的装置状态,用于底层控制器的跟踪参考;底层控制器通过反馈控制或者前馈控制计算出预期装置状态与当前装置状态的误差,驱动假肢执行这些命令,形成控制闭环。结果表明,该通用控制框架可完整阐释主动型下肢假肢的人—机—环境共融关系,明确了分层控制策略的层级任务,为未来主动型下肢假肢的发展提供了理论指导。     

Model Identification of a Micro Air Vehicle

This paper is focused on the model identification of a Micro Air Vehicle （MAV） in straight steady flight condition. The identification is based on input-output data collected from flight tests using both frequency and time dorrtain techniques. The vehicle is an in-house 40 cm wingspan airplane. Because of the complex coupled, multivariable and nonlinear dynamics of the aircraft, linear SISO structures for both the lateral and longitudinal models around a reference state were derived. The aim of the identification is to provide models that can be used in future development of control techniques for the MAV.     

Molecular,Viral and Clinical Features of Alcohol- and Non-Alcohol-Induced Liver Injury

Hepatic cells are sensitive to internal and external signals. Ethanol is one of the oldest and most widely used drugs in the world. The focus on the mechanistic engine of the alcohol-induced injury has been in the liver, which is responsible for the pathways of alcohol metabolism. Ethanol undergoes a phase I type of reaction, mainly catalyzed by the cytoplasmic enzyme, alcohol dehydrogenase (ADH), and by the microsomal ethanol-oxidizing system (MEOS). Reactive oxygen species (ROS) generated by cytochrome (CYP) 2E1 activity and MEOS contribute to ethanol-induced toxicity. We aimed to: (1) Describe the cellular, pathophysiological and clinical effects of alcohol misuse on the liver; (2) Select the biomarkers and analytical methods utilized by the clinical laboratory to assess alcohol exposure; (3) Provide therapeutic ideas to prevent/reduce alcohol-induced liver injury; (4) Provide up-to-date knowledge regarding the Corona virus and its affect on the liver; (5) Link rare diseases with alcohol consumption. The current review contributes to risk identification of patients with alcoholic, as well as non-alcoholic, liver disease and metabolic syndrome. Additional prevalence of ethnic, genetic, and viral vulnerabilities are presented.     

The ultrastructure of malpighian tubules and the chemical composition of the cocoon of Aeolothrips intermedius Bagnall (Thysanoptera)

The secretory activity of the two branched malpighian tubules (MTs) of the second‐instar larva in Aeolothrips intermedius is described. MTs of adult thrips have the typical ultrastructure of excretory epithelium with apical microvilli containing long mitochondria and a rich system of basal membrane infoldings. In the second‐instar larva just before pupation, the ultrastructure of MT epithelial cells is dramatically different, and there are numerous huge Golgi systems in the cytoplasm. These cells are involved in an intense secretory activity to produce an electron‐dense product which is released into the MTs lumen. This secretion is extruded from the hindgut and used by the second‐instar larva to build an elaborate protective cocoon for pupation. Electron‐spray‐ionization mass spectrometry analysis of the cocoon revealed the presence of a β‐N‐acetyl‐glucosamine, the main component of chitin, which is also present in the cocoons of Neuroptera and some Coleoptera. J. Morphol., 2010. © 2009 Wiley‐Liss, Inc.     

Minimizing model fitting objectives that contain spurious local minima by bootstrap restarting

Objective functions that arise when fitting nonlinear models often contain local minima that are of little significance except for their propensity to trap minimization algorithms. The standard methods for attempting to deal with this problem treat the objective function as fixed and employ stochastic minimization approaches in the hope of randomly jumping out of local minima. This article suggests a simple trick for performing such minimizations that can be employed in conjunction with most conventional nonstochastic fitting methods. The trick is to stochastically perturb the objective function by bootstrapping the data to be fit. Each bootstrap objective shares the large-scale structure of the original objective but has different small-scale structure. Minimizations of bootstrap objective functions are alternated with minimizations of the original objective function starting from the parameter values with which minimization of the previous bootstrap objective terminated. An example is presented, fitting a nonlinear population dynamic model to population dynamic data and including a comparison of the suggested method with simulated annealing. Convergence diagnostics are discussed.