A review on molecular topology: applying graph theory to drug discovery and design

Molecular topology is an application of graph theory and statistics in fields like chemistry, biology, and pharmacology, in which the molecular structure matters. Its scope is the topological characterization of molecules by means of numerical invariants, called topological indices, which are the main ingredients of the molecular topological models. These are statistical models that are instrumental in the discovery of new applications of naturally occurring molecules, as well as in the design of synthetic molecules with specific chemical, biological, or pharmacological properties. In this review, we focus on pharmacology, which is a novel field of application of molecular topology. Besides summarizing some recent developments, we also seek to bring closer this interesting biomedical application of mathematics to an interdisciplinary readership.

大气化学模式的数值计算方法

大气化学模式计算的一个重要研究热点是如何快速精确地对相互关联的非线性常微分方程组(ODES)进行数值积分求解。由于大气中各物种寿命长短相差很大,导致ODE_s具有了很强的刚性,因而在数值求算过程中存在着计算精度和计算效率的平衡问题。笔者介绍了当前几种常见的大气化学模式的计算方法,包括GEAR,QSSA(MQSSA),Y&B(MY&B),RADM,LSODE,SMVGEAR,小参数法,Gong and Cho及TWOSTEP等,并结合当前本领域内的部分研究成果对一些重要的方法进行了比较和分析。      

基于观测的大气气溶胶散射吸湿增长因子模型研究 ——以2006 CAREBeijing加强观测为例

在2006年北京加强观测期间,以颗粒物－液体转换采集系统(PILS)测量的气溶胶各可溶性离子组分的质量浓度、颗粒物分级采样器(MOUDI)测量的各可溶性离子组分及有机碳(OC)、碳黑(EC)的分级质量谱分布为基础,对离子组分的可能存在形态进行判断,计算了化学组分质量浓度及各化学物种的粒径数谱浓度;利用Mie模型及各化学物种的密度、折射率、吸湿粒径增长因子等参数计算得到外混、内混的粒子群在干燥状态、不同相对湿度下的散射系数,最终计算得到不同化学组分外混、内混状态下的散射吸湿增长因子;将模型模拟的气溶胶散射吸湿增长因子与观测得到的该因子进行对比,发现模拟值与观测值能够在一定误差范围内吻合,实现了该因子的闭合实验.     

Development of a unique topology for a hard-turning micro-scale machine tool

A micro-scale machine tool (mMT) topology is developed for turning hardened steel bearing components. The topology utilizes the principle of leverage to increase accuracy and stiffness and incorporates decoupling to reduce unwanted motion of the tool. Performance specifications required that the static stiffness is at least 10 N/μm and dynamic stiffness is at least 30 N/μm in all directions. The kinematics for the topology are developed to enable control over the position and orientation of the tool tip. The effect of the topology on rake angle is determined and the topology is adjusted so as to minimize the rake angle variation during the cut. Cutting tests are performed to determine cutting parameters for achieving a low surface roughness and to estimate the accuracy of the machine. Tests show that the hard-turning mMT can achieve surface roughness below 25 nm Ra, diametrical accuracy of 1 μm and peak-to-valley roundness deviation (RONt) below 0.35 μm.     

Determining the acidity and chemical composition of fog,haze and cloud droplets in Israel

The chemistry and acidity of individual droplets were analyzed in samples of fog, haze and cloud collected at Tel Aviv University on the Mediterranean seacoast and at the top of Mt Meron and of Mt Carmel in northern Israel. Acidity was measured using pH paper in a cascade impactor. The characteristics of droplets and interstitial particles 0.3–20.0 μm in size were identified using microspot and electron microscopy techniques.The results revealed the following: (1) the aerosols in the micrometer and sub-micrometer range were mostly very acidic droplets, with pH as low as 2.0, caused by the presence of sulfuric acid; (2) lower acidity was associated with an increase in droplet size, due to dilution by condensation or nucleation scavenging of mineral dust, i.e. gypsum, calcite and dolomite; (3) both acidic and alkaline droplets contained significant amounts of sulfur; and (4) the alkaline droplets contained minerals and salt solutions of Na₂SO₄, CaSO₄, or NaCl.     

Model-based topology analysis for environmentally conscious power plant operation

Plant operation is tightly linked with plant topology. Each operation task is executed in one or more structure units, which might be associated with negative environmental impacts. In order to design and manage environmentally conscious plant operation it is essential to provide systematic mechanism to model plant topology with respect to environmental measures. The selection of plant topology to perform certain operation requires understanding and evaluation of life cycle activities. In this research, model-based topology analysis is proposed and used to evaluate different operation scenarios in view of life cycle assessment and applied on a case study thermal power plant.     

低温燃烧合成纳米Ni掺杂TiO2光催化剂的表征及活性研究

采用低温燃烧合成法制备了Ni掺杂TiO₂光催化剂,通过紫外-可见漫反射光谱(UV-Vis DRS)、X射线粉末衍射(XRD)、激光散射、热重-差示扫描量热分析(TG-DSC)等方法对催化剂的光吸收特性、晶相组成、粒度分布、升温过程中化学变化等进行了表征,以亚甲基蓝为模型污染物考察了催化剂在可见光下的光催化活性.结果表明,相对P25而言,Ni掺杂TiO₂的光吸收带边红移,当Ni/Ti原子比为0.4时,催化剂的带隙宽度为2.3eV,对应的吸收带边为564nm;催化剂晶型以锐钛矿TiO₂为主,随Ni掺杂量增大,NiTiO₃比例升高;催化剂粒径主要分布在50～150nm之间,占总量的96.9%;升温过程中催化剂在445.2℃发生晶型转化,出现锐钛矿和NiTiO₃晶体.催化剂显示出较高的催化活性,在可见光作用150min后最高可使93.9%的亚甲基蓝分解,活性高于P25.     

近代分析化学进展

随着科技的进步，分析化学正经历着重大的变革。作者从我国分析化学的现状及分析化学的几个重要分支和交叉学科；生命科学分析，化学计量学，光度分析，色谱分析，电化学分析等方面阐述了近代分析化学的进展。     

生物修复在治理海洋环境污染中的应用

介绍了治理海洋环境污染的方法,包括物理处理法、化学处理法、生物修复法等。与传统的化学、物理方法相比,生物修复有很多优点,如费用低、副作用少等。     

绿色化学与可持续发展

绿色化学是一门从源头上阻止污染的化学,它吸收了传统化学化工、环境、物理、生物、材料和信息等学科的最新理论和技术,代表了化学化工科学理念的重大变革,具有可持续发展的意义。本文介绍了绿色化学的一般概念及绿色化学与环境保护的关系,从主要研究内容及发展现状和趋势等方面阐明了绿色化学是可持续发展的必由之路。     

Die organischen Verbindungen und Komplexe von Germanium,Zinn und Blei

This field is of special interest within the organometallic chemistry, which was and still is one of the most developing areas of chemistry for twenty years. The electronic structure around the atoms of germanium, tin, and lead favors both polar and radical reactions, and a plentiful coordination chemistry, too. Modern quantum chemistry arrived at these heavy atoms and allows better understanding also of low valent species, R₂M. Chiral compounds with asymmetric Sn atoms, an object aimed at since 1905, have been prepared now, and dynamic stereochemistry has been studied. Industrial use of organotins has grown quickly and includes stabilization of plastics and plant and material protection as well. Biomethylation and environmental problems open this field both to biochemists and ecologists.     

Carbon source in the future chemical industries

Rising crude oil prices favour the exploitation of hitherto unutilised energy carriers and the realisation of new technologies in all sectors where carbon is used. These changed economic constraints necessitate both savings in conventional petrochemistry and a change to oil-independent carbon sources in the chemical industry. While, in coal chemistry, the synthesis and process principles of petrochemistry — fragmentation of the raw material and subsequent buildup of molecular structures — can be maintained, the raw material structure largely remains unchanged in the chemistry of renewable raw materials. This lecture is to demonstrate the structural as well as the technological and energy criteria of the chemistry of alternative carbon sources, to forecast the chances of commercial realization and to discuss some promising fields of research and development.     

绿色化学教育的探讨

当今全球十大环境问题几乎每都直接与化学和化学工业污染污染有关，如何减少化学和化学工业所造成的污染是许多环境保护工作者所研究的重要课题，本文介绍了绿色化学的内涵，提出了实施绿色化学理论教育和绿色化学实验教育的具体措施，绿色化学及绿色化学教育对环境保护具有重大而深远的意义。     

Das Studium in Technischer Biologie an der Eidgenössischen Technischen Hochschule Zürich

A new Curriculum, termed Technical Biology (or Biotechnology) has been instituted at the Swiss Federal Institute of Technology in Zurich, Switzerland. Biotechnology is regarded not as a Natural Science, but as an Engineering Science. On a solid basis of two years of mathematics, physics, chemistry, physical chemistry, and biology, courses are offered in technical microbiology and process and control engineering.     

催化技术对绿色化学的影响研究

绿色化学又称环境友好化学,它是在化学产品的设计、制造和应用过程中运用一套原理和理论来减少或者消除对有害物质的生产和利用的一门学科。绿色化学工艺的目标是用化学的技术和手段去减少或消除那些对人类健康有害的原料、产物、副产物、溶剂和试剂等的产生或应用。催化技术是绿色化学工艺研究及应用的重要手段,简要介绍了绿色化学与催化的关系、催化剂的研究进展及典型实例,并列举了几种新型绿色催化剂,详细分析了其环境友好特性。     

Multiphase chemistry in a microphysical radiation fog model—A numerical study

A microphysical radiation fog model is coupled with a detailed chemistry module to simulate chemical reactions in the gas phase and in fog water during a radiation fog event. In the chemical part of the model the microphysical particle spectrum is subdivided into three size classes corresponding to non-activated aerosol particles, small and large fog droplets. Chemical reactions in the liquid phase are separately calculated in the small and in the large droplet size class. The impact of the chemical constitution of activated aerosols on fogwater chemistry is considered in the model simulations. The mass transfer of chemical species between the gas phase and the two liquid phases is treated in detail by solving the corresponding coupled differential equation system. The model also accounts for concentration changes of gas-phase and aqueous-phase chemical species which are induced by turbulence, gravitational settling and by evaporation/condensation processes.Numerical results demonstrate that fogwater chemistry is strongly controlled by dynamic processes, i.e. the vertical growth of the fog, turbulent mixing processes and the gravitational settling of the particles. The concentrations of aqueous-phase chemical species are different in the two droplet size classes. Reactands with lower water solubility are mainly found in the large droplet size class because the characteristic time for their mass transfer from the gas phase into the liquid phase is essentially longer than the characteristic time for the formation of large fog droplets. Species with high water solubility are rapidly transferred into the small fog droplets and are then washed out by wet deposition before these particles grow further to form large droplets. Thus, the concentrations of the major ions (NO₃⁻, NH₄⁺) are much higher in small than in large droplets, yielding distinctly lower pH values of the small particles. In the present study the reaction of sulfur with H₂O₂ and the Fe(III)-catalysed autoxidation of S(IV) are the major S(VI) producing mechanisms in fog water. Most of the time the sulfur oxidation rates are higher in the large than in the small droplets. Fogwater deposition by gravitational settling occurs mainly in the large droplet size class. However, since in the small droplets the concentrations of chemical species with very good water solubility are relatively high, in both droplet size classes the total wet deposition of these reactands is of the same order of magnitude.     

Myonische Atome in Physik,Chemie und Archäometrie

A survey is given of properties, formation, and application of muonic atoms in physics, chemistry, and archeometry. In the field of physics the measurement of nuclear charge distributions and vacuum polarization as well as the slowing down of muons in matter are treated in some detail, and in the fields of chemistry and archeometry, non-destructive quantitative chemical analysis of bulk material and, with the help of suitable beam setting, also of selected parts of the specimen.     

发动机绿色化学设计──发动机虚拟化学反应器模型

在化学和化学工程意义上,发动机使用的生态环境有害性与发动机系统3个虚拟化学反应器（燃烧化学反应器、润滑化学反应器和排放化学反应器）中的反应物料（燃料、润滑油、添加剂和催化剂等）及其化学反应（自由基反应、摩擦化学反应和催化转化反应等）有关．发动机绿色化学设计旨在根据绿色化学原理和发动机化学反应器模型,探索降低或消除发动机化学反应器产生有害物质的化学技术．发动机绿色化学设计是发动机绿色设计的重要方面,其以绿色效应为目标,获得发动机材料、能源与环境之间的化学相容性．     

绿色化学思想在大型化工企业环境规划中的应用

绿色化学是新兴的无污染的化学，它的提出和应用为化学工业防治环境污染，转变经济增长方式提供了新的思想、理论和技术。探讨了绿色化学思想的内涵，设计了以绿色化学为核心的化工企业环境规划体系，并在某化工企业环境规划中进行了应用。