Estimating the Location and Time Course of Synaptic Input from Multi-Site Potential Recordings

A method is introduced that permits accurate and robust extraction of the location and time course of synaptic conductance from potentials recorded on either side of, and perhaps at some distance from, the synapse in question. It is shown that such data permits one to fully overcome the problems typically associated with lack of spaceclamp. The method does not presume anything about the nature of the time course and yet is applicable to branched, active cells receiving simultaneous input from a number of synapses.     

Peptide separation by Hydrophilic-Interaction Chromatography: a review

Recent developments in the separation of peptides by high-performance liquid chromatography (HPLC) using polar sorbents with less polar eluents are summarized in this review. This separation mode is now commonly referred to as Hydrophilic-Interaction Chromatography (HILIC). The retention mechanism and chromatographic behavior of polar solutes under HILIC conditions are studied on TSKgel Amide-80 columns, which consist of carbamoyl groups bonded to a silica gel matrix, using a mixture of acetonitrile (MeCN)–water containing 0.1% trifluoroacetic acid (TFA). Some applications are given in peptide field using Hydrophilic-Interaction Chromatography.     

A local influence approach applied to binary data from a psychiatric study

Recently, a lot of concern has been raised about assumptions needed in order to fit statistical models to incomplete multivariate and longitudinal data. In response, research efforts are being devoted to the development of tools that assess the sensitivity of such models to often strong but always, at least in part, unverifiable assumptions. Many efforts have been devoted to longitudinal data, primarily in the selection model context, although some researchers have expressed interest in the pattern-mixture setting as well. A promising tool, proposed by Verbeke et al. (2001, Biometrics 57, 43-50), is based on local influence (Cook, 1986, Journal of the Royal Statistical Society, Series B 48, 133-169). These authors considered the Diggle and Kenward (1994, Applied Statistics 43, 49-93) model, which is based on a selection model, integrating a linear mixed model for continuous outcomes with logistic regression for dropout. In this article, we show that a similar idea can be developed for multivariate and longitudinal binary data, subject to nonmonotone missingness. We focus on the model proposed by Baker, Rosenberger, and DerSimonian (1992, Statistics in Medicine 11, 643-657). The original model is first extended to allow for (possibly continuous) covariates, whereafter a local influence strategy is developed to support the model-building process. The model is able to deal with nonmonotone missingness but has some limitations as well, stemming from the conditional nature of the model parameters. Some analytical insight is provided into the behavior of the local influence graphs.     

冈崎姬小蜂生物学特性的研究

 对美洲斑潜蝇幼虫寄生蜂──冈崎姬小蜂Neochrysocharis okazakii Kamijo生物学特 性的研究结果表明：（1）补充蜜汁能显著延长成蜂寿命;（2）在20～33℃范围内各虫 态发育速率与温度呈线性相关,发育起点温度81℃,完成一个世代需要1887日·度的积 温;成蜂寿命与温度呈负线性相关,产卵量在30℃时达到最大;内禀增长率与温度呈线性相 关。     

Multi-compartmental modelling and experimental design for glucose transport studies in insulin-resistant rats

Many pathologies are associated with abnormalities of glucose metabolism or with perturbations of its transport (type 2 diabetes or insulin-resistance). The pre-diabetic state is characterised by a state of insulin-resistance, in others words a defect of glucose transport in insulin-sensible tissues, such as muscles and adipose tissues. The mathematical modelling of experimental data can be an excellent method to explore the mechanisms implied in the studied biological phenomenon. Thus, starting from a symbolic formulation like the compartmental modelling, it can be possible to develop a theoretical basis for the observation and to consider the best-adapted experiments for the study. We showed with mathematical models that [123I]-6-deoxy-6-iodo-D-glucose (6-DIG), shown as a tracer of glucose transport in vitro, could point out this transport abnormality. To quantify the insulin resistance, we estimated the fractional transfer coefficients of 6-DIG from the blood to the organs. We realised many studies to lead to a satisfying model; special attention has been paid to the precision of the parameter to select the best model. The results showed that by associating experimental data obtained with 6-DIG activities and an adapted mathematical model, discriminating parameters (in and out fractional transfer coefficients) between the two groups (control and insulin-resistant rats) could be pointed out.     

Protein fold recognition without Boltzmann statistics or explicit physical basis.

We present a fast method for finding optimal parameters for a low-resolution (threading) force field intended to distinguish correct from incorrect folds for a given protein sequence. In contrast to other methods, the parameterization uses information from >10(7) misfolded structures as well as a set of native sequence-structure pairs. In addition to testing the resulting force field's performance on the protein sequence threading problem, results are shown that characterize the number of parameters necessary for effective structure recognition.     

参数仪器变量估计近似分布方差的一种算法

本文对更一般的结构模型给出了参数的一种常用的仪器变量估计近似分布方差的一种算法．并且给出了未知真值x服从指数分布的例子．此算法对生物科学中统计规律的探讨有一定的应用价值．     

火炬松胚性细胞悬浮培养物的生长参数变化

以火炬松（PinustaedaL.）成熟合子胚来源的胚性愈伤组织为材料建立了胚性细胞悬浮系,测定了其培养物的鲜重、干重、细胞体积和胚数及培养液中的pH值、电导率和蔗糖浓度等生长参数在培养过程中的变化动态。结果表明,在培养周期内,培养液中的pH值、电导率和蔗糖浓度的逐步降低与培养物的鲜重、干重、细胞体积和胚胎数的逐步增加保持一致性。在培养至18—21d,pH值、电导率和蔗糖浓度均接近或降到最低点,而胚数及细胞体积的增长都达到最高点。     

Wistar大鼠牙周炎动物模型口腔菌群及病理观察

本文以Ｗｉｓｔａｒ大鼠为实验对象,以激素＋剥离的方法成功地制造了类似人类牙周炎动物模型。纵观牙周炎全过程,菌群失调贯穿自始至终,菌群失调持续一定时间后才出现病理改变,证明菌群失调是导致牙周炎的因素之一。