权值混合更新的神经网络液位控制方法及应用

综合考虑现场液位控制的需求、增量式PID实质及算法计算复杂度,设计了一权值混合更新的神经网络控制器。输入层到隐层的权值向量更新采用梯度下降法,隐层到输出层的权值向量更新采用Levenberg Marquardt算法,并结合信赖域理论对相关参数设置进行了详细说明。双容水箱液位控制实验表明,调节阀动作次数少,控制器参数人工设置简单,并具有良好的动态性能、抗扰性能及稳态精度,并可在省却流量变送器的前提下取代常规的PID串级控制。     

文献检索课开设30年的回顾

山东理工大学图书馆开设文献检索课30年,实现了前辈们将文献检索课建成高校三大公共课程之一的愿望。此文重点介绍该校近5年文献检索课的改革举措,包括课程普及和提高两个方面。普及是实现全校范围的授课,提高是达到教育部的共享课标准。作者认为文献检索课的成功在于图书馆教育科研职能被广泛认可,这是图书馆由被动服务向主动服务的重要转折,实践证明此举能够显著提升图书馆在校内的地位。     

p38 MAPK Inhibitor (SB203580) and Metformin Reduces Aortic Protein Carbonyl and Inflammation in Non-obese Type 2 Diabetic Rats

Microvascular and macrovascular diseases are the main causes of morbidity in type 2 diabetes patients through chronic hyperglycaemic condition via oxidative stress and inflammation. Reactive oxygen species (ROS) activate p38 MAPK phosphorylation and inflammation which enhances protein modification by carbonylation. The use of metformin and a p38 MAPK inhibitor is hypothesised to reduce ROS production and inflammation but effects of metformin and p38 MAPK inhibitor (SB203580) on ROS production and inflammation in vascular type 2 diabetes mellitus non-obese (T2DM) have not been investigated. The Goto-Kakizaki rat T2DM model was divided into three groups as T2DM, T2DM treated with 15 mg/kg bw metformin and T2DM treated with 2 mg/kg bw SB203580 for 4 weeks. Rat aortas were isolated and protein carbonyl (PC) contents were measured by spectrophotometric DNPH assay. Aortic IL-1ß level was determined by ELISA. Results showed that aortic PC contents in the T2DM group were significantly higher than in non-diabetic rats. Treatment with metformin or SB203580 significantly reduced PC contents while only metformin significantly reduced IL-1ß levels. Findings indicated that metformin reduced ROS production and inflammation in diabetic vessels and possibly reduce vascular complications in non-obese T2DM.     

Biochemical characterization of the recombinant schistosome tegumental protein SmALDH_312 produced in E. coli and baculovirus expression vector system

BackgroundThe heterologous expression of parasitic proteins is challenging because the sequence composition often differs significantly from host preferences. However, the production of such proteins is important because they are potential drug targets and can be screened for interactions with new lead compounds. Here we compared two expression systems for the production of an active recombinant aldehyde dehydrogenase (SmALDH_312) from Schistosoma mansoni, which causes the neglected tropical disease schistosomiasis.ResultsWe produced SmALDH_312 successfully in the bacterium Escherichia coli and in the baculovirus expression vector system (BEVS). Both versions of the recombinant protein were found to be active in vitro, but the BEVS-derived enzyme showed 3.7-fold higher specific activity and was selected for further characterization. We investigated the influence of Mg²⁺, Ca²⁺ and Mn²⁺, and found out that the specific activity of the enzyme increased 1.5-fold in the presence of 0.5 mM Mg²⁺. Finally, we characterized the kinetic properties of the enzyme using a design-of-experiment approach, revealing optimal activity at pH 7.6 and 41°C.ConclusionsAlthough, E. coli has many advantages, such as rapid expression, high yields and low costs, this system was outperformed by BEVS for the production of a schistosome ALDH. BEVS therefore provides an opportunity for the expression and subsequent evaluation of schistosome enzymes as drug targets.How to cite: Harnischfeger J, Beutler M, Salzig D, et al. Biochemical characterization of the recombinant schistosome tegumental protein SmALDH_312 produced in E. coli and baculovirus expression vector system. Electron J Biotechnol 2021;54. https://doi.org/10.1016/j.ejbt.2021.08.002     

提高普通话水平增强学生就业能力——以西华大学为例

近几年来高校毕业生就业形势日益严峻,用人单位和社会需求对大学毕业生综合素质及能力要求越来越高,流利使用普通话就是其中重要能力之一。虽然对于流利使用普通话的重要性人人认识到位,但当代大学生的普通话使用能力的总体状况不容乐观,高校一直在开展的普通话培训与水平测试也有很大的提升空间。文章在阐述了普通话对大学生就业竞争中的重要性后,审视了我国高校学生的普通话水平、培训与测试的现状,提出了改进当前高校普通话水平测试现状的若干思考与实现途径。     

Do timing and reference frame of feedback influence high-stakes educational outcomes?

In a field experiment with fifth and sixth graders in secondary schools, students received feedback about their rank level or the change in their rank in math either a few days or immediately before the school year’s final math exam. Early feedback overall enhances exam performance while late feedback worsens it. We find this pattern to hold for level feedback in general and for change feedback when negative. Heterogeneity analyses suggest the effects are mostly driven by boys, who also negatively update ability beliefs in response to feedback.     

基于单张二维图像的三维建模研究

对基于单张二维图像重建三维模型问题进行深入研究,对目前使用的方法进行比较分析,提出了基于紧水平支集的S FS三维模型重建方法。首先改进了基于快速匹配算法求解的紧水平支集方法,以提高紧水平支集求解的精度和效率,并将此方法应用到求解S FS问题,提出基于水平集快速求解S FS问题的方法;接下来为解决S FS固有的凹凸二义性问题,基于分水岭的思想寻找凹凸分界线,以此确定产生凹凸二义性的区域用以进行重建;最后利用拓扑变换重构凹陷区域,得到正确的三维模型。     

铜胁迫对小叶黄杨生理生态特征的影响

采用水培试验的方法,研究不同浓度铜（0、20、40、60、80和100mg/L）胁迫条件下小叶黄杨的生长和生理特征。结果表明,随铜浓度的增加,小叶黄杨的生物量（鲜重）逐渐下降;蛋白质含量呈下降趋势;叶绿素含量先上升后下降;丙二醛的含量逐渐增加;超氧化物歧化酶和过氧化物酶的活性均呈先增加后下降的趋势。     

活化AMPK促进骨骼肌蛋白质降解过程中FoxO3 mRNA的表达

目的通过给大鼠注射AMPK激动剂AICAR,提高大鼠骨骼肌中AMPK的活性,观察FoxO3 mRNA表达量的变化,探讨骨骼肌蛋白质的降解机制。方法 24只雄性SD大鼠,8月龄,180～200 g,根据用药后的取材时间分4组:AICAR注射后1 h组、2 h组、7 h组,生理盐水对照组。采用同位素技术测定腓肠肌中AMPK活性变化,采用荧光定量PCR技术,测定腓肠肌中MuRF1、MAFbx、FoxO3基因表达量的变化。结果 AICAR注射后1 h组、2 h组、7 h组,AMPK活性与对照组相比显著性升高(P<0.05或P<0.01),AICAR注射后7 h组,AMPK活性开始下降;AICAR注射后1 h组、2 h组,MAFbx mRNA、MuRF1mRNA表达量与对照组相比非常显著性升高(P<0.01),分别升高2.45、2.23倍和2.67、2.30倍;AICAR注射后7 h组,MuRF1 mRNA表达量显著性升高(P<0.05),升高2.01倍;FoxO3mRNA表达量在AICAR注药组与对照组之间没有显著差异。结论 研究认为大鼠一次性注射AICAR,提高AMPK活性,可能不是通过促进FoxO3 mRNA的表达,促进骨骼肌蛋白质的降解。     

县级图书馆开展图书漂流活动的实践与思考

图书漂流活动的开展既节约了资源也考验了诚信,更重要的是传递了文明,促进了和谐,推动了全民阅读活动的开展。所以,如果把此活动引入县级图书馆,作为一种新的服务模式普及推广,在社会形成一座无形流动的图书馆,那么对增强图书馆的吸引力,推动文化事业的大发展、大繁荣具有极大助推作用。本文探索出了适宜县级图书馆漂流的方法及工作流程供大家参考。