Kinetic analysis of γ-glutamyltransferase reaction process for measuring activity via an integration strategy at low concentrations of γ-glutamyl p-nitroaniline

At 0.12 mmol/L γ-glutamyl p-nitroaniline (GGPNA), an improved integrated method was developed for kinetic analysis of γ-glutamyltransferase (GGT) reaction process and the integration with the classical initial rate method to measure serum GGT. For the improved integrated method, an integrated rate equation, which used the predictor variable of reaction time and considered inhibitions by both GGPNA and products, was nonlinearly fit to GGT reaction processes. For the integration strategy, classical initial rates were estimated when GGPNA consumption percentages were below 50%; otherwise, maximal reaction rates of GGT were estimated by the improved integrated method and converted into initial rates according to the differential rate equation at 0.11 mmol/L GGPNA. The integration strategy was validated using optimized GGT kinetic parameters and 10-s intervals to record reaction curves within 8.0 min. By the integration strategy, there was a linear response from 0.9 to 32.0 U/L GGT, coefficients of variation were below 3.5% for GGT from 8.0 to 32.0 U/L (n=5), and GGT activities in clinical sera responded linearly to their classical initial rates at 2.00 mmol/L GGPNA with an expected slope. Therefore, the integration strategy was successful in measuring GGT at 0.12 mmol/L GGPNA.     

Postgraduate fellows as teaching assistants in human anatomy: an experimental teaching model at a Chinese research university

Postgraduate fellowship training programs are expanding at Chinese universities. This growing cadre of advanced trainees calls for the development of new learning and training models wherein postgraduate fellows have an ample opportunity to teach more junior learners, thereby expanding their own knowledge base and competitiveness for future employment. Educational reform at Sun Yat-Sen University has recently allowed postgraduate fellows to act as teaching assistants for undergraduate anatomy courses. This model is common in western countries but is novel in China.     

Korean deaf adolescents' awareness of thematic and taxonomic relations among ordinary concepts represented by pictures and written words

Individuals' relative awareness of thematic and taxonomic relations is influenced by factors such as language and background knowledge. Relatively weak in Korean language skills and also having relatively limited social opportunities, Korean deaf adolescents might be different from hearing adolescents in how they make decisions in taxonomically and thematically associated entities represented by pictures and words. Experiment 1 indicated that deaf adolescents had longer reaction times than hearing adolescents in a forced-choice decision-making task. Both deaf and hearing adolescents had shorter reaction times and higher accuracies with pictures than with words, but deaf adolescents' differences were bigger than those of hearing adolescents. Experiment 2 further showed that deaf adolescents had lower accuracies than hearing adolescents in a priming task of living-nonliving categorization. Both deaf and hearing adolescents had shorter reaction times with taxonomic than with thematic categories, but deaf adolescents' difference was bigger than that of hearing adolescents. In conclusion, Korean deaf adolescents were aware of thematic and taxonomic relations less than hearing adolescents in general. They were more likely than hearing adolescents to show the advantage of pictures over words in their performance in conceptual activities and to prefer taxonomic to thematic associations for written words in Experiment 2.     

Response to weaning and dietary L-glutamine supplementation: metabolomic analysis in piglets by gas chromatography/mass spectrometry

A novel metabolomic method based on gas chromatography/mass spectrometry (GC-MS) was applied to determine the metabolites in the serum of piglets in response to weaning and dietary L-glutamine (Gln) supplementation. Thirty-six 21-d-old piglets were randomly assigned into three groups. One group continued to suckle from the sows (suckling group), whereas the other two groups were weaned and their diets were supplemented with 1% (w/w) Gln or isonitrogenous L-alanine, respectively, representing Gln group or control group. Serum samples were collected to characterize metabolites after a 7-d treatment. Results showed that twenty metabolites were down-regulated significantly (P<0.05) in control piglets compared with suckling ones. These data demonstrated that early weaning causes a wide range of metabolic changes across arginine and proline metabolism, aminosugar and nucleotide metabolism, galactose metabolism, glycerophospholipid metabolism, biosynthesis of unsaturated fatty acid, and fatty acid metabolism. Dietary Gln supplementation increased the levels of creatinine, D-xylose, 2-hydroxybutyric acid, palmitelaidic acid, and α-L-galactofuranose (P<0.05) in early weaned piglets, and were involved in the arginine and proline metabolism, carbohydrate metabolism, and fatty acid metabolism. A leave-one-out cross-validation of random forest analysis indicated that creatinine was the most important metabolite among the three groups. Notably, the concentration of creatinine in control piglets was decreased (P=0.00001) compared to the suckling piglets, and increased (P=0.0003) in Gln-supplemented piglets. A correlation network for weaned and suckling piglets revealed that early weaning changed the metabolic pathways, leading to the abnormality of carbohydrate metabolism, amino acid metabolism, and lipid metabolism, which could be partially improved by dietary Gln supplementation. These findings provide fresh insight into the complex metabolic changes in response to early weaning and dietary Gln supplementation in piglets.     

Poisson Growth Mixture Modeling of Intensive Longitudinal Data: An Application to Smoking Cessation Behavior

Intensive longitudinal data (ILD) have become increasingly common in the social and behavioral sciences; count variables, such as the number of daily smoked cigarettes, are frequently-used outcomes in many ILD studies. We demonstrate a generalized extension of growth mixture modeling (GMM) to Poisson-distributed ILD for identifying qualitatively distinct trajectories in the context of developmental heterogeneity in count data. Accounting for the Poisson outcome distribution is essential for correct model identification and estimation. In addition, setting up the model in a way that is conducive to ILD measures helps with data complexities - large data volume, missing observations, and differences in sampling frequency across individuals. We present technical details of model fitting, summarize an empirical example of patterns of smoking behavior change, and describe research questions the generalized GMM helps to address.     

一种基于局部分析面向事件的查询扩展方法

针对用户获取事件类信息的需求,提出了一种基于局部分析面向事件LA-EO(local analysis-event-oriented)的查询扩展方法,该方法将查询项区分为事件项和限定项两类分别处理.文章重点讨论了面向事件的查询项分析、事件项的扩展以及查询项与文本相似度的计算等问题.围绕突发事件领域,使用搜索引擎和定点采集相结合的方法收集了4011篇文本,设置了10个查询项对本文提出的方法进行了实验比较.结果表明:LA-EO与Rocchio机制(记作LA-Rocchio)和局部上下文分析(记作LA-LCA)扩展方法相比,对事件类信息的检索,LA-EO具有更优的检索性能.     

Influence of polarized bias and porous silicon morphology on the electrical behavior of Au-porous silicon contacts

INTRODUCTION Porous silicon (PS) attracts the attention of many researchers due to the possibility of developing PS based devices, including optoelectronics, photo re- sistors, solar cells and light emitting diodes (Balucani et al., 1999; Palma et al., 1999a; Stievenard and Deresmes, 1995). To integrate PS into electronic circuits or to develop PS based devices, the electrical properties of this material must be studied thoroughly. It is a difficult case because this material has a ve…     

GLOBAL ATTRACTIVITY IN NICHOLSON'S BLOWFLIES

In this paper we further study the delay differential equation N(t) = - δN(t) pN(t -τ)e~((-aN)(g-τ)),t≥0 (*)used in describing the dynamics of Nicholson's blowflies. When p>δ, We establish newsufficient conditions for the positive equilibrium N~* of (*) which is a global attractor. Ourcriteria improve correspondent results obtained by Kulenovic, Ladas and Sficas [1], and Soand Yu [2].     

多通道神经信号激励模块的研制及其动物实验

为了研究植入式神经功能再生微电子系统,设计了功能激励神经信号产生模块.首先用分立器件设计并实现了体外应用的单通道功能激励神经信号产生模块,并将该模块成功应用于激励老鼠和兔子的坐骨神经和脊椎神经的神经功能再生微电子系统的动物试验.在此基础上,设计了用于12个电极点的卡肤电极或者10个电极点的剑状电极四通道神经信号激励模块.用5只老鼠和2只兔子进行了3次坐骨神经和脊髓神经束活体动物试验.试验中,功能激励神经信号产生模块再生了大鼠体内的自发神经信号和模拟的神经信号,模块所产生的信号使大鼠和兔子的腿部、尾巴甚至脚趾产生了相应的动作,验证了神经功能再生微电子系统的可行性.