抗药物依赖药效团模型的构建与虚拟筛选

运用计算机辅助药物设计方法,基于多巴胺D2和D3受体部分激动剂构建具有抗药物依赖功效的药效团模型。再以该药效团模型作为提问结构,在天然产物数据库中进行虚拟筛选,利用分子对接技术,对筛选结果进行分析和评价,初步得到具有抗药物依赖功效的目标化合物。最后对目标化合物进行虚拟水溶性、肠道吸收性和血脑屏障通透性研究,为抗药物依赖新药的研发提供理论基础。     

流感病毒神经氨酸酶抑制剂的理性筛选

介绍了理性筛选流感病毒神经氨酸酶抑制剂的全过程，共分4个阶段：1)化合物数据库类药性处理；2)建立神经氨酸酶抑制剂三维药效团并对目标数据库进行构象搜索；3)分子对接及对接后分析；4)神经氨酸酶抑制模型的建立及待测化合物的活性检测。活性检测后发现4个活性化合物，其中Ic。为10。M的化合物1个．Ic，。为10^-6M的化合物2个，IC50为10^-7M的化合物1个。应用理性筛选方法，从化合物数据库中挑选出部分化合物进行神经氨酸酶抑制活性的筛选，减少了药物筛选的盲目性，提高了药物发现的机率。     

GPR40激动剂药效团模型的构建及验证

目的:构建和验证GPR40激动剂药效团模型。方法:采用生物活性跨越1~160000 nmol?L~(-1)的23个GPR40激动剂小分子作为训练集进行药效团模型的构建;利用测试集验证、Fisher验证及分子对接方法对模型进行评价;根据所构建的药效团模型,设计并合成2个全新结构的化合物,通过正常小鼠糖耐量试验的验证。结果:筛选得到由1个氢键受体(HBA)、2个疏水中心(HP)、1个芳环中心(RA)组成的最佳模型(Correl.=0.971,Config=16.645,△cost=58.370),依据药效团模型设计得到的与药效团匹配较高的化合物Lyb-438能显著降低正常小鼠餐后0.5 h血糖(P0.05)。结论:所构建的药效团模型具有较强的预测能力和较高的可信性,为进一步的数据库搜索及寻找新型小分子GPR40激动剂提供了依据。     

尿道选择性α_1-肾上腺素受体拮抗剂药效团的构建

目的 :建立具有尿道选择性α1 肾上腺素受体拮抗剂的药效团模型。方法 :选择对受体亚型和尿道组织均有高亲和力的化合物 ,经计算机建模、分子动力学优化、系统搜索得到一系列低能构象 ,通过Apex 3D软件计算并构建药效团初步模型 ,再参照已有的构效关系数据进行筛选、判别。结果 :得到 3个符合要求的药效团 ,它们均含有一个碱性中心和芳环中心 ,还存在一个氢位点 (HST)。结论 :该模型有助于我们设计、合成活性高且副作用低的新型抗前列腺增生药物。     

尿道选择性α1—肾上腺素受体拮抗剂药效团的构建

目的：建立具有尿道选择性α１－肾上腺素受体拮抗剂的药效团模型。方法：选择对受体亚型和尿道组织的有高亲和力的化合物,经献计献策发子动力学优化、系统搜索得到一系列低能构象,通过Ａｐｅｘ－３Ｄ软件计算并构建药效团初步模型,再参照已有的构效关系数据进行筛选、判别。结果：得到了３个符合要求的药效团,它们均含有一个碱性中心和芳环中心,还存在一个氢位点（ＨＳＴ）。结论：该模型有助于我们设计、合成活性高且副作用低     

新型酪氨酸激酶水分子抑制剂的三维药效团研究

对受体酪氨酸激酶（ＲＴＫ）的药物抑制对控制恶性肿瘤具有重要意义。最近发现的苄叉丙二腈化合物家族对ＲＴＫ中的ＨＥＲ２受体具有的抑制作用。本文对这一系列化合物进行了柔性的三维药效团分析,得到了一个预测能力委好的药效团模型、线性回归系数Ｒ＝０．９９５８。这个模型对于研究此类化合物的结构与活性关系,以及评估此类未知化合性具有重要作用。     

基于端粒G-四链体受体构建具有抗肿瘤功效的药效团模型

端粒G-四链体DNA是由端粒末端富含鸟嘌呤的DNA序列通过自身组装形成的一种特殊的二级结构。配体通过结合/稳定端粒G-四链体DNA可以抑制端粒酶延长端粒DNA,从而抑制了癌细胞赖以生存的端粒维持机制。本文运用Discovery Studio3.5软件中的Structure Based Pharmacophore(SBP)方法,以分子间端粒G-四链体DNA四聚体的结构为基础,构建了具有抗肿瘤功效的药效团模型。并通过分析测试集与药效团模型的匹配情况,对模型进行了验证。证明了该模型的正确性和可靠性,此药效团模型可用于天然产物数据库的高通量虚拟筛选。     

基于复杂网络探讨金钗石斛潜在活性成分组及其作用机制

为发现金钗石斛潜在活性成分组,本研究从化合物的分子结构和生物活性入手进行计算模拟,通过对141个已知化合物的分子骨架进行结构相似度聚类,发现了11个结构相似的成分组,而大部分成分组具有明显的ADME活性。另一方面,结合靶点虚拟筛选和KEGG通路富集,构建并分析"化合物-靶点-通路"网络,预测金钗石斛的重要潜在活性成分和重要作用机制,揭示了5个成分组与特定生物功能间的相关性。潜在活性成分组的虚拟筛选为揭示金钗石斛药效物质基础提供了理论依据。     

整合素α_vβ_3受体配体的计算机辅助设计

肿瘤血管生成是肿瘤生长、浸润和转移过程中不可缺少的生物过程,整合素α_vβ_3对肿瘤血管生成起着重要作用。研发具有高亲和力和高特异性的整合素α_vβ_3受体配体在针对肿瘤血管生成进行靶向诊断与靶向治疗中具有重要意义。计算机辅助药物设计技术的问世,极大地推动了新型整合素α_vβ_3受体配体的研发。整合素α_vβ_3受体细胞外区X射线晶体衍射结构的获得为针对整合素α_vβ_3受体的药物设计奠定了基础。计算机辅助药物设计包括基于分子对接法(Docking)的直接药物设计和基于药效团的间接药物设计,Docking可预测配体-蛋白的相互作用、对受体-配体结合进行三维构效关系研究、设计具有高亲和力与选择性的新型配体。通过将小分子数据库与α_vβ_3受体(PDB号为1L5G)进行对接,筛选出具有较高亲和力的α_vβ_3受体拮抗剂-3(3-吡啶基)-3-[4-[2-(5,6,7,8-四氢[1,8]萘啶-2)乙基]吲哚-1]丙酸和3,4-二氯苯基双胍,后者与目前已知的配体具有不同的受体结合模式。在间接药物设计中,提出了以Arg的带正电荷的侧链、Asp的带负电荷的侧链和Gly的疏水基团为药效团特征的三点药效团模型和以氢键供体、氢...     

家蝇GABAA受体萜类抑制剂先导化合物的筛选

用距离比较法(DISCOtech)构建的家蝇GABAA受体萜类抑制剂药效团模型为基础建立了提问结构,以三维数据库搜索软件3DFS为工具,在三维结构中草药数据库(TCMD)中进行了搜索.对搜索结果使用改进的Linpinsky五原则进行筛选,挑选21个化合物进行CoMFA活性预测,活性预测值较高.结果分析表明,3DFS-类杀虫剂筛选-CoMFA活性预测生物活性方法是一种有效的筛选先导化合物的方法.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).