One Question,Multiple Answers: Biochemical and Biophysical Screening Methods Retrieve Deviating Fragment Hit Lists

Fragment‐based lead discovery is gaining momentum in drug development. Typically, a hierarchical cascade of several screening techniques is consulted to identify fragment hits which are then analyzed by crystallography. Because crystal structures with bound fragments are essential for the subsequent hit‐to‐lead‐to‐drug optimization, the screening process should distinguish reliably between binders and non‐binders. We therefore investigated whether different screening methods would reveal similar collections of putative binders. First we used a biochemical assay to identify fragments that bind to endothiapepsin, a surrogate for disease‐relevant aspartic proteases. In a comprehensive screening approach, we then evaluated our 361‐entry library by using a reporter‐displacement assay, saturation‐transfer difference NMR, native mass spectrometry, thermophoresis, and a thermal shift assay. While the combined results of these screening methods retrieve 10 of the 11 crystal structures originally predicted by the biochemical assay, the mutual overlap of individual hit lists is surprisingly low, highlighting that each technique operates on different biophysical principles and conditions.     

INTROGRESSING PHEROMONE QTL BETWEEN SPECIES: TOWARDS AN EVOLUTIONARY UNDERSTANDING OF DIFFERENTIATION IN SEXUAL COMMUNICATION

As a first step toward understanding how noctuid moths evolve species-specific pheromone communication systems, we hybridized and backcrossed two closely related moth species, Heliothis virescens (Hv) and H. subflexa (Hs), which differ qualitatively and quantitatively in their multi-component sex pheromone blends. We used amplified fragment length polymorphism (AFLP) marker-based mapping of backcross families to determine which of the 30 autosomes in these moths contained quantitative trait loci (QTL) controlling the percentages of specific chemical components in the pheromone blends. In two previous backcrosses to Hs, we found a strong depressive effect of Hv-chromosome 22 on the percentage of three acetate components in the pheromone gland. These acetates are present in Hs and absent in Hv. Here, we describe how we introgressed Hv-chromosome 22 into the genomic background of Hs. Selection for Hv-chromosome 22 started from backcross 3 (BC₃) females. All females that had Hv-chromosome 22 and a low percentage of acetates (< 3% of the total amount of pheromone components present) were backcrossed to Hs males. In BC₅ to BC₈, we determined whether Hv-chromosome 22 was present by a) running only the primer pairs that would yield the markers for that chromosome, and/or b) determining the relative percentages of acetates in the pheromone glands. Either or both genotype and phenotype were used as a criterion to continue to backcross these females to Hs males. In BC₉, we confirmed the isolation of Hv-chromosome 22 in the Hs genomic background, and backcrossed the males to Hs females to eliminate the Hv-sex chromosome as well as mitochondrial DNA. The pheromone composition was determined in BC₃, BC₅, and BC₁₁ females with and without Hv-chromosome 22. All backcross females with Hv-chromosome 22 contained significantly less acetates than females without this chromosome. In addition, BC₃ females with Hv-chromosome 22 contained significantly more Z11-16:OH than BC₃ females without Hv-chromosome 22. However, in BC₅ and BC₁₁ females, the correlation between Z11-16:OH and Hv-chromosome 22 was lost, suggesting that there are separate QTL for the acetates and for Z11-16:OH, and that the relative amount of the alcohol component is only affected in epistasis with other (minor) QTL. Now that we have succeeded in isolating the chromosome that has a major effect on acetate production, we can test in behavioral experiments whether the presence of acetates may have been a driving force for a shift in pheromone composition. Such tests are necessary to move towards an evolutionary understanding of the differentiation in sexual communication in Heliothis spp. moths.     

对缺血性脑卒中患者二级预防、卒中风险及日常生活能力的门诊随访调查研究

目的：通过调查及概述本院门诊缺血性卒中患者的医疗现状，评价神经科门诊缺血性卒中患者二级预防中期随访结果，Essen卒中风险评分量表（EsRS）的有效性和可靠性及其与日常生活能力评定（mRS）的相关性。方法：以2010．7至2010．9内新发脑梗死门诊随访患者为研究对象，调查患者基本情况、危险因素、合并用药情况，并进行Essen及mRS评分。1年后随访患者，评价心脑血管终点事件发生率及其与Essen评分的关系。结果：人组102例患者，平均年龄67．4±岁，分别伴有糖尿病、高血压、高脂血症、动脉粥样硬化性疾病，追踪其一年后使用抗血小板药、降压药、降脂药及降糖药的比例。Essen评分与mRS评分呈正向相关关系；EsRS≥3分的患者终点事件发生率显著高于EsRs〈3分的患者。结论：目前缺血性脑卒中的二级预防仍存在药物应用不足、慢性基础疾病控制率低、长期依从性较差等情况。Essen评分可以有效地评估患者发生终点事件的风险以及缺血性脑卒中患者的预后。     

Self-esteem stability and depressive symptoms in acute stroke rehabilitation: Methodological and conceptual expansion.

Objectives: Explore the relationship of self-esteem level, self-esteem stability, and other moderating variables with depressive symptoms in acute stroke rehabilitation. Measures: One hundred twenty participants completed measures of state self-esteem, perceived recovery, hospitalization-based hassles, impairment-related distress, and tendency to overgeneralize negative self-connotations of bad events. Self-report of depressive symptoms was collected at admission and on discharge. Four regression analyses explored the relationship of self-esteem level and stability and each of 4 moderating variables (perceived recovery, hassles, impairment-related distress, and overgeneralization) with depressive symptoms at discharge. Results: Analyses indicated significant 3-way interactions in the 4 regression models. In general, individuals with unstable high self-esteem endorsed greater depressive symptoms under conditions of vulnerability (e.g., lower perceived recovery) than did individuals with stable high self-esteem. Under conditions of vulnerability, participants with stable low self-esteem indicated the highest levels of depressive symptoms. Implications: Self-esteem level and stability interact with psychological, environmental, and stroke-specific variables to predict depressive symptoms at discharge from stroke rehabilitation. This suggests the viability of self-esteem stability in exploring depressive symptoms in this setting and the complexity of emotional adjustment early after stroke. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of human serum albumin on protein array using scanning tunneling microscopy

Electrical detection of biological binding events, such as protein–protein interaction and DNA hybridization, has emerged as an alternative method to conventional colorimetric and fluorescence based methods. In this study, we demonstrate an electrical detection technique of protein array which can be simply extended for multifunctional measurements and detection of biological binding events on micro-scale array. Micro-contact technique was used for the fabrication of protein chip. The fabricated protein array on Au substrate was characterized by fluorescence microscopy and scanning tunneling microscopy (STM). The chip was designed to investigate immunocomplexes comprised of our model protein, human serum albumin (HSA), corresponding antibody fragments, and Au nanoparticle–antibody conjugates. The peak-like pulse obtained by electrical tunneling current between these complexes and the STM tip varies on the surface density of the bound complexes. Using the electrical detection technique based on STM, 100 fg/mL of HSA could be successfully detected by STM. Importantly, the proposed concept of measurement could allow multiple analyses of analytes at nano-scale array, which is difficult to be analyzed by conventional fluorescence based method.     

关于液压系统中“液阻”的探讨

以液压系统的液压压力、流量和功率为参量,借鉴欧姆定律提出“液阻”概念,并以此初步归纳了各种“导流”液压元器件的“液阻”共性.藉此各种液压元器件所共有的“液阻”属性,探讨了面向液压系统的数学运算及分析评估的可行性.     

Group psychotherapy focusing on self-concept change following acquired brain injury: A pilot investigation.

Objective: The current study explored the effectiveness of a group therapy intervention that was focused specifically on self-concept changes following acquired brain injury (ABI). Method: Eighteen individuals in the postacute phase of recovery underwent a 6-week group therapy intervention and were administered a self-concept measure before and after the intervention. Results: Group members showed a significant increase (improvement) in self-concept ratings at the end of the group intervention. Conclusions: Although the results of this study suggest that this intervention may be helpful in improving self-concept following ABI, further exploration is clearly warranted. Future research is needed to investigate the impact of self-concept on emotional adjustment, participation in rehabilitation activities, and functional outcome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

多接地点闪电的梯级先导与回击过程的研究

利用成像率为1000幅/s的高速数字化摄像系统和电场变化仪,对在一次回击过程中具有多个接地分支的闪电(MGPF)进行了研究。结果表明:MGPF回击前的梯级先导由包含2~4个脉冲的脉冲束组成,脉冲束间的时间间隔平均值约为26μs,脉冲间的时间间隔平均值约为5μs;广东MGPF回击过程中和的电荷量约为4.5C,青海的约为11C;广东MGPF发生比例为16.7%,青海的为17.6%;一次回击的多个接地分支多发生在首次回击。通过分析发现,MGPF的形成与闪电的梯级先导、连接过程等有重要关系。闪电在一次回击过程中具有多个接地分支对雷电防护方法和设计的改进提出了更高的要求。     

220 kV江龙东线雷击跳闸分析

根据220kV江龙东线跳闸现场收集的杆塔尺寸、保护动作及接地电阻等资料，采用绕击几何电气模型和反击耐雷水平等理论，并结合GPS雷电信息系统提供的地闪雷电流值，分析了线路跳闸的原因，并提出了相关整改建议。     

OVSF码分配算法研究

提出1种优先选择极左碎片的信道化码分配算法,该算法用很简单的方式降低了码阻塞率。将新算法与已有的极左法和权重法进行比较,理论分析和计算机仿真表明,极左碎片法具有与极左法相近的简单性,在码阻塞率和公平性方面几乎与权重法一样好,是简单、高效和公平的综合性能最好的算法。该算法可应用于以OVSF码作为信道化码的各种DS-CDMA系统。