液压传动与自动控制系统动态性能分析

研究汽车液压传动过程中液压缸中的压力变化过程,对液压系统中相关的液压泵、液压缸、管道阀门等主要工作环节进行了建模和受力分析,得到工作过程中各处受力情况,并设计了一个液压控制系统的基本工作原理图,对液压系统中的主要阀门、管壁、液体流量等液压控制中的主要参数进行了建模和抽象,得到了液压缸中液体流量和压缩比的相关关系式.最后对液压传动系统中的动态控制性能进行了分析,得到了其压力、流量、容量等主要参数的性能关系.     

Effect of microcystin-LR on protein phosphatase 2A and its function in human amniotic epithelial cells

Due to their toxicity, the increased distribution of microcystins (MCs) has become an important worldwide problem. MCs have been recognized as inhibitors of protein phosphatase 2A (PP2A) through their binding to the PP2A catalytic subunit. However, the exact mechanism of MC toxicity has not been elucidated, especially concerning the cellular response and its autoregulation. To further dissect the role of PP2A in MC-induced toxicity, the present study was undertaken to determine the response of PP2A in human amniotic epithelial (FL) cells treated with microcystin-LR (MCLR), one of the MC congeners. The results show that a low-dose treatment of MCLR in FL cells for 6 h induced an increase in PP2A activity, and a high-dose treatment of MCLR for 24 h decreased the activity of PP2A, as expected. The increased mRNA and protein levels of the PP2A C subunit may explain the increased activity of PP2A. Furthermore, MCLR altered microtubule post-translational modifications through PP2A. These results further clarify the underlying mechanism how MCLR affects PP2A and may be helpful for elucidating the complex toxicity of MCLR.     

“It Lets Me Fight the Bad Guys”: An Exploration Into the Factors Predicting Enjoyment of Violent Video Games

In an exploratory survey that sampled video gamers, participants were asked to indicate why they enjoy playing their favorite video game. On the basis of ESRB ratings, we compare those whose favorite game is violent to those whose favorite game is nonviolent. Consistent with self-determination theory, the findings suggest need for autonomy and competence are important motivating factors. However, the findings also suggest fans of violent games differed from fans of nonviolent games in the degree to which arousal, liking violence, playing the vicarious hero, and playing the vicarious villain drive enjoyment. Furthermore, being able to play the hero and “fight bad guys” was a significant predictor of enjoyment of violent games. Implications for self-determination theory and theories of media enjoyment are discussed.     

Cloning and efficient expression of <Emphasis Type="Italic">Bacillus sp.</Emphasis> BH072 <Emphasis Type="Italic">tasA</Emphasis> gene in <Emphasis Type="Italic">Escherichia coli</Emphasis>

The Bacillus strain BH072 isolated from a honey sample showed strong antifungal activity against phytopathogen. Gene cloning test demonstrated that the strain had a tasA gene encoding an antifungal TasA protein. Although the wild strain simultaneously produced various antifungal substances, only the physicochemical property and antifungal activity of TasA protein were unclear due to the difficulty in extraction. In this study, tasA gene encoding the protein from Bacillus sp. BH072 was amplified by using the polymerase chain reaction (PCR) method and cloned into pET 28a (+) vector, and then expressed in host cells Escherichia coli BL21 (DE3). The expressed proteins were collected by centrifugation and ultrasonic treatment, and then purified by using nickel-nitrilotriacetic acid (Ni-NTA) metal affinity column and dialysis methods. The result of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) test showed that an expected protein band appeared with a size of 31 kDa. The expressed products possessed antifungal activity against the phytopathogenic indicator strain Botrytis cinerea. A genetically engineered strain tasA of E. coli was established in this study which can efficiently express Tas A protein.     

现代生化技术综合性设计性实验教学的探索与实践

综合性设计性实验是高校深化实验教学改革,提高教育质量,培养应用型人才的重要措施.其目的是提高和培养学生综合分析问题、解决问题的能力及激发学生学习的主动性和创造性.针对目前综合性设计性实验存在的一些问题,在《现代生化技术》的综合性设计性实验中,对实验内容的设计、实验实施过程及实验考核等方面进行了研究与探索,取得一定成效.对其它相关课程的实验教学具有一定借鉴意义.     

AtHsfAla 对拟南芥幼苗在干旱中生理指标的影响

以过量表达 AtHsfAla 及 AtHsfAla 基因沉默的转基因植株为材料,通过控制土壤水分进行干旱处理,结果显示,过量表达型干旱处理后的存活率最大,而基因沉默型最小,表明 AtHsfA1a 能增强植物的抗旱性。为了从生理水平研究 AtHsfA1a 提高抗旱性的机制,研究发现过量表达型的叶片相对含水量和叶绿素含量最高,而沉默型最低。不同基因型植株的 H2 O2和 MDA 的含量正好相反,说明 AtHsfA1a 通过保护细胞膜而减小细胞所受氧化伤害来提高抗旱能力。     

浅析《澳大利亚高等教育残疾支持计划》

1990年,澳大利亚联邦政府把残疾人视为高等教育中的弱势群体,自此澳大利亚联邦政府开始制定政策来保障残疾人的高等教育入学机会。《澳大利亚残疾人支持计划》的目的就是保障该类群体的入学机会。本文通过分析的政策文本,政策实施,政策理念和特点来分析《高等教育残疾人》政策。     

General University Requirements at Hong Kong Polytechnic University: evaluation findings based on student focus groups

Under the new four-year undergraduate programme, a general education framework titled ‘General University Requirements’ (GUR) has been developed and implemented since 2012/2013 at Hong Kong Polytechnic University (PolyU). To evaluate the implementation and effectiveness of the GUR in its first year, focus group interviews with students were carried out. In 13 focus groups, 62 first-year students from eight faculties/schools who took GUR subjects in 2012/2013 academic year were interviewed by trained researchers. Results showed that students generally had good perceptions of the GUR in terms of the subject content, teaching methods and the overall effectiveness of the subjects. The interactive teaching and learning initiatives adopted in GUR subjects were particularly appreciated, although students expressed minor concerns on the administration of GUR subjects. The results suggest that the first-year implementation of the GUR at PolyU was generally smooth and successful from the perspectives of the students.     

基于任务驱动的数学建模教学方法研究

通过进行数学建模竞赛的教学及培训工作,可极大地拓展学生的知识面,提高学生自己动手解决实际问题的能力,提高学生创新能力,增强学生的综合素质。主要介绍和讨论了基于任务驱动的数学建模培训及教学方法。该方法主要通过教师布置任务,鼓励学生自主地讨论并解决问题,通过自我评价和教师指导,使学生能掌握和拓展自己的知识。然后给出了具体的案例,并以淮南师范学院的建模辅导为例进行了相关的总结。