Effects of osmotic stress on antioxidant enzymes activities in leaf discs of P<Subscript>SAG12</Subscript>-<Emphasis Type="Italic">IPT</Emphasis> modified gerbera

Leaf senescence is often caused by water deficit and the chimeric gene PSA612-1PT is an auto-regulated gene delaying leaf senescence. Using in vitro leaf discs culture system, the changes of contents of chlorophylls, carotenoids, soluble protein and thiobarbituric acid reactive substance （TBARS） and antioxidant enzymes activities were investigated during leaf senescence of PSA612-1PT modified gerbera induced by osmotic stress compared with the control plant （wild type）. Leaf discs were incubated in 20%, 40% （w/v） polyethylene glycol （PEG） 6 000 nutrient solution for 20 h under continuous light [ 130 μmol/（m^2·s）]. The results showed that the contents of chlorophylls, carotenoids and soluble protein were decreased by osmotic stress with the decrease being more pronounced at 40% PEG, but that, at the same PEG concentration the decrease in the transgenic plants was significantly lower than that in the control plant. The activities of superoxide dismutase （SOD）, catalases （CAT）, ascorbate peroxidase （APX）, guaiacol peroxidase （GPX） and dehydroascorbate reductase （DHAR） were stimulated by PEG treatment. However, the increases were higher in PSA612-IPT transgenic plants than in the control plants, particularly at 40% PEG treatment. Lipid peroxidation （TBARS content） was increased by PEG treatment with the increase being much lower in transgenic plant than in the control plant. It could be concluded that the increases in the activities ofantioxidant enzymes including SOD, CAT, APX, GPX and DHAR were responsible for the delay of leaf senescence induced by osmotic stress.     

Novel distribution pattern of fibrinolytic components in rabbit tissues extract： a preliminary study

Objective: The purpose of this work was to investigate the distribution pattern of fibrinolytic factors and their inhibitors in rabbit tissues. Methods: The components of the fibrinolytic system in extracts from a variety of rabbit tissues, including tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), plasminogen (Plg), plasmin (Pl) and α2 plasmin inhibitor (α2PI), were determined by colorimetric assay. Results: The tissue extracts in renal, small intestine, lung, brain and spleen demonstrated strong fibrinolytic function, in which high activity of tPA, Plg and Pl was manifested; whereas in skeletal muscle, tongue and stomach, higher activity of PAI-1 and α2PI showed obviously. Also excellent linear correlations were found between levels of tPA and PAI-1, Pl and α2PI, Plg and Pl. In related tissues, renal cortex and renal marrow showed distinctly higher activity of tPA and lower activity of PAI-1, with the levels of Plg and Pl in renal cortex being higher than those in renal marrow, where the α2PI level was higher than that in renal cortex. Similarly, the levels of tPA, Plg and Pl in small intestine were higher than those in large intestine, but with respect to PAI-1 and α2PI, the matter was reverse. In addition, the fibrinolytic activity in muscle tissue was lower, however, the levels of tPA, Plg, and Pl in cardiac muscle were obviously higher than those in skeletal muscles, and the levels of PAI-1 and α2PI were significantly lower than those in skeletal muscle. Conclusion: Our data demonstrate that a remarkable difference of the fibrinolytic patterns exists in rabbit tissues, which has probable profound significance in understanding the relationship between the function of haemostasis or thrombosis and the physiologic function in tissues.     

Relationship between hyperuricemia and metabolic syndrome

Objective: To investigate the relationship between metabolic syndrome and hyperuricemia. Methods: A total of 2 374 subjects who received health examination in our hospital from Jan. 2004 to Dec. 2006 were enrolled in our study. Hyperuricemia is defined as ≥7 mg/dl (in men) or ≥6.0 mg/dl (in women). Metabolic syndrome was defined using AHA/NHLBI (American Heart Association/National Heart, Lung, and Blood Institute) criteria. Results: (1) The overall prevalence of hyperuricemia was 13.10%. The condition was more common in men than in women (19.07% vs 3.42%). (2) Among men, uric acid concentration is statistically significantly positively correlated with waist circumference, blood pressure, and triglyceride. Uric acid is negatively correlated with serum high-density lipoprotein-cholesterol (HDL-C). Uric acid concentration is most strongly correlated with serum triglyceride (r=0.379) and waist circumference (r=0.297). Among women, statistically significant positive correlations were noted for the serum uric acid concentrations with waist circumference, triglyceride and fasting plasma glucose. Serum triglyceride (r=0.329) and waist circumference (r=0.234) are most strongly correlated with uric acid concentrations. (3) Men with hyperuricemia had a 1.634-fold increased risk of metabolic syndrome as compared with those without hyperuricemia odds ratio (OR)=1.634, P=0.000. Women with hyperuricemia had a 1.626-fold increased risk of metabolic syndrome (OR=1.626, P=0.000) as compared with those without hyperuricemia. Conclusion: Hyperuricemia is prevalent among Chinese population. Additionally, serum uric acid is positively associated with metabolic syndrome.     

预印本平台数据开放共享政策的内容构成与特点剖析

[目的 /意义]开放科学环境下,探究预印本平台的数据开放共享政策有助于保障科研利益相关者的数据质量,推动研究数据更加开放、共享、安全与透明。[方法 /过程]基于研究团队跟踪的125个预印本平台中共63份数据开放共享政策文本,利用网络调查与文本分析的方法进行内容挖掘与特点剖析。[结果 /结论 ]通过分析得出预印本平台的数据开放共享政策在数据创建、数据存储、数据发布、数据访问、数据重用5个阶段的主要特征,为更多预印本平台在未来制定完备的数据开放共享政策提供切入点与参考思路。     

在线社区用户承诺影响因素研究：一项元分析

[目的 /意义]对在线社区用户承诺影响因素的相关实证研究进行梳理和再分析,以解释影响在线社区用户承诺的一般性因素,为后续研究提供参考。[方法 /过程]运用元分析方法,选取以用户承诺为研究主题、以在线社区为研究情境的文献作为样本文献,归纳和识别在线社区的用户承诺影响因素,并进一步探索影响异质性的调节变量。[结果 /结论 ]显著影响在线社区用户承诺的因素包括系统外部、需求动机及用户感知三个类别的10个变量,与在线社区用户承诺为中度相关关系的有情感依恋、信息性动机、感知娱乐性、信息质量,而社交动机、社会互动、满意度、信任、感知收益、社区认同与用户承诺高度相关。在线社区类型会对情感依恋、社会互动、感知娱乐性等变量与用户承诺之间的关系产生调节。研究结果对未来深入研究和不同情境研究具有借鉴意义,也对在线社区运营具有实践指导作用。     

大学物理实验教学团队建设问题探讨

结合三峡大学实验教学团队建设的实践,阐述了地方综合性大学物理实验教学团队建设的措施及效果,强调了实验教学团队建设应发挥团队聚合效应,优化团队的学缘结构、年龄结构和职称结构,突出地方综合性大学的特色.     

近代物理实验考试模式和成绩评价体系的创新与实践

结合课程特点和人才培养目标,通过对近代物理实验教学进行改革,探索和尝试多元化的考试方法,达到客观公正地评价学生的综合素质和创新能力、科学全面地监控教学质量和规范教学行为、充分提高仪器设备的利用率、推动校风和考风建设的目的。     

基于混合内容分发网络的流媒体系统设计与实现

在大规模网络分发方面,内容分发网络(CDN)占据主导地位,可降低网络传输延时,但成本过高,可扩展性不强,而点对点(P2P)网络相比有明显的互补优势.在结合CDN与P2P技术互补的基础上,提出了一种在骨干网部署CDN、在区域网内部署P2P的混合分发网络,并给出了面向流媒体系统的设计与实现.性能测试表明,所提出的混和内容分发网络可有效减少骨干网流量,快速响应用户请求,并能解决区域P2P网内种子节点少而导致内容分发效率低下的问题.     

扩招背景下提高实践教学质量的方法研究与实践

探讨了扩招背景下工程训练实践教学面临的机遇和挑战,对工程训练中提高教学质量的方法和途径进行了研究,提出了通过构建工程训练体系、实践教学保障体系和考核评价体系提高实践教学质量的思路,并结合整个教学团队的工作实践,阐述了在实践教学中的应用情况.     

摒弃传统 尝试创新——参与式方法在农村小学英语教师培训中的运用

目前,农村小学英语教师培训的形式单一,培训有效性不佳。通过访谈和问卷调查的方式,在分析当前小学英语教师培训现状、成人学习特点的基础上,让培训者运用参与式方法对教师进行培训,提高培训的质量,提升教师的学习热情,加速教师专业发展和改善教师生存状态,并期望能达到推动基础教育发展的目的。