Monitor In Vivo Dynamics of Avian Influenza Viruses Using Bioorthogonal-conjugated Nearinfrared Quantum Dots

<正>Highly pathogenic avian influenza A viruses are emerging pandemic threats that have caused several outbreaks with high mortality in human beings in the past decades.The infection of avian infl uenza viruses,such as subtype H5 and H7,could cause a series of severe respiratory and extra-respiratory complications,     

Novel Formation Mechanism of Quantum Dots

Scientists have long been work-ing hard to identify laws un-derlying materials growth atmicroscopic level. With the devel-opment of new growth methods andcharacterization techniques on theatomic scale over the past decade,breakthroughs have been achieved.It is now generally acknowl-edged that atoms that are depositedon crystal surfaces, through a methodknown as molecular beam epitaxy,often form surfaces covered withnumerous small mounds rather thansmooth layers, if the substrate tem-perature i…     

用Lambda Probe监控Tomcat实例的内存使用

介绍了Lambda Probe的基本功能,说明了它的安装部署及其注意事项,给出内存使用监控中遇到的问题及其解决办法。最后,指出了Lambda Probe及其在监控Tomcat实例内存使用方面的不足之处。     

Whirl Dynamics of Pendulous Flywheels Using Bond Graphs

Bond graphs are used to generate the equations of motion of a whirling flywheel. The formulation is shown to be a natural one when control forces and moments are included for active control of the whirling modes. Critical frequencies are interpreted as rotational speeds at which non-zero equilibrium configurations exist for displacements (as opposed to the more familiar momenta) and arise when the system dynamics matrix of the complete whirl motion has two zero eigenvalues. In addition, oscillatory modes corresponding to non-zero eigenvalues are examined. Time simulations and other numerical results are given for an example flywheel system which has been proposed for electric utility energy storage.     

产业集聚效应的系统动力学建模与仿真

从系统动力学视角提出产业集聚效应的基本分析框架,结合集聚效应形成的正反馈特征,分析了人才、技术和资金"流"的因果关系.建立产业集聚效应的系统流图和系统动力学模型,应用Vensim PLE对模型进行了仿真模拟,验证了模型的有效性与应用价值.结果表明,模型对产业集聚效应的实际演化过程具有较高的拟合程度,并能够为区域经济管理提供有效的决策支持.     

城市建设系统的动力学模型研究

本文以复杂系统论和系统动力学为指导,从宏观和微观两个角度综合考虑,给出了城市建设系统的动力学模型,以探寻城市建设过程中的基本规律,促进城市建设同社会经济的协调发展和城市建设模式的进一步合理化,为城市建设质量的提高提供支持。     

产学研技术联盟稳定性的系统动力学建模与仿真

从系统动力学视角提出产学研技术联盟稳定性的基本分析框架,结合联盟稳定性的反馈特征,从匹配性、互动性和共赢性三方面分析了物质流、信息流和能量流的因果关系,建立产学研技术联盟稳定性的系统流图和系统动力学模型,应用Vensim PLE对模型进行仿真模拟,验证了模型的有效性与应用价值。结果表明,声誉、合作经验、资源和规模禀赋等外部变量对联盟稳定性的影响较弱,而信任、投机行为、利益分配合理度等内部变量会导致联盟稳定性的较大波动。     

高校团队内知识转移的系统动力学建模与仿真

以系统论与控制论为基础描述了个体知识转移过程,运用系统动力学的方法分析了高校团队内知识转移的因果关系.构建了系统动力学模型,使用Vensim PLE软件实现了系统仿真,并验证了模型的有效性和灵敏度.结果表明,该模型能够较好地拟合实际的团队内知识转移过程,并能为相似的知识转移过程提供有效的决策支持.     

产学研知识联盟运行和发展机理的系统动力学分析

产学研知识联盟是产学研战略联盟的核心内容.应用SD研究产学研知识联盟运行和发展机理,分析产学研知识联盟中目标要素主体要素以及影响因素;并分析各要素在产学研知识联盟过程中的因果关系,并建立产学研知识联盟的知识资源SD模型、知识产品生产SD模型及社会支撑SD模型;最后给出知识联盟运行系统及各子系统的运行模型.强调其动态发展的内在动因与模式,不仅对其从整体上进行时间、空间上的全貌描述,而且能够为系统地分析其发展的根源提供参考和依据.     

基于CPLD的高频电路多功能时钟模块设计

文章介绍了一种基于CPLD的高频电路的多路不同频率同步时钟输出模块的设计方法,采用单一高频时钟作为时钟源输入,通过CPLD的分频电路设计实现输出多路不同频率同步时钟,利用有限状态基设计实现CPLD的外部控制接口,实现对CPLD输出时钟频率的任意调节。有效满足复杂的高频电路设计中需要提供多路不同频率同步时钟的要求。     

Free Radical Scavenging Properties of Skin and Pulp Extracts of Different Grape Cultivars In Vitro and Attenuation of H2O2-Induced Oxidative Stress in Liver Tissue Ex Vivo

Grapes are the richest source of antioxidants due to the presence of potent bioactive phytochemicals. In this study, the phytochemical contents, scavenging activities and protective role against H₂O₂-induced oxidative stress in liver tissue ex vivo of four grape (Vitis vinifera) cultivars extracts, namely Flame seedless (black), Kishmish chorni (black with reddish brown), Red globe (red) and Thompson seedless mutant (green), were evaluated. The total phenolics and flavonoids content in pulp or skin fractions of different grape cultivars were in the range of 47.6–310 mg gallic acid equivalent/g fresh weight (fw), and 46.6–733.3 µg catechin equivalent/g fw respectively. The scavenging activities in skin of different grape varieties against 2,2-diphenyl-1-picrylhydrazyl (44–58 %), hydrogen peroxide (15.3–18.6 %), and hydroxyl radicals (50–85 %), were higher than pulp of the corresponding cultivars. These scavenging activities of grape extracts were found to be significantly (p < 0.01) correlated with the levels of total phenols, flavonoids and ascorbic acid. Liver tissues from goat treated with H₂O₂ (500 μM) showed significantly decreased GSH content by 42.9 % and activities of catalase by 50 % and glutathione reductase by 66.6 %; while increased thiobarbituric acid reactive substances and nitric oxide level by 2.53- and 0.86-fold, respectively, and activity of glutathione S-transferase by 0.96-fold. Grape skin extracts showed the stronger protective activity against H₂O₂-induced oxidative stress in liver tissue ex vivo, than its pulp of any cultivar; and the Flame seedless (black) cultivar showed the highest potential. In conclusion, our study suggested that the higher antioxidant potential, phytochemical contents and significant scavenging capacities in pulp and skin of grape extracts showed the protective action of grape extracts against H₂O₂-induced oxidative stress in liver tissue ex vivo.     

绿色革命揭开新篇章——生物技术应用于农业的成果和效益

生物技术——基因工程、细胞工程、酶工程和发酵工程,正广泛应用于农业领域:动植物良种培育、快速繁殖、动植物保护、固氮基因工程和土壤改善,以及农产品的深层次加工,并取得了明显的经济效益。生物技术是第二次绿色革命的先导技术,其应用于农业的特点和优势是:开发的层次深,应用的领域广,产出的效益高。     

Evaluation of Flow Rate,pH, Buffering Capacity,Calcium, Total Proteins and Total Antioxidant Capacity Levels of Saliva in Caries Free and Caries Active Children: An In Vivo Study

The purpose of this study was to evaluate the relationship between the physicochemical properties of saliva such as flow rate, pH, buffering capacity, calcium level, total protein and total antioxidant levels in caries free and caries active children. The present study included one hundred and twenty healthy children who were divided into two groups; group I and group II comprising of age groups 7–10 and 11–14 years, respectively. Both the groups were then sub-divided equally according to gender. They were further divided into caries free and caries active with 15 children in each group. Unstimulated saliva was collected by suction method and flow rates were determined. The samples were then analyzed for pH, buffering capacity, total protein, calcium and total antioxidant capacity. The data was statistically analyzed using student t test (unpaired). The results revealed that when all these parameters were compared among the caries free and caries active children, flow rate, pH, buffering capacity were slightly reduced in caries active children, but total protein and total antioxidant capacity of saliva increased significantly in caries active children and the total calcium decreased significantly in caries active children. Within the limitation of this study, we conclude that, the physicochemical properties of saliva play a major role in the development of caries.