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Maxwell's equations are replaced by a set of finite difference equations. It is shown that if one chooses the field points appropriately, the set of finite difference equations is applicable for a boundary condition involving perfectly conducting surfaces. An example is given of the scattering of an electromagnetic pulse by a perfectly conducting cylinder.

A mechanism for electron transfer reactions is described, in which there is very little spatial overlap of the electronic orbitals of the two reacting molecules in the activated complex. Assuming such a mechanism, a quantitative theory of the rates of oxidation-reduction reactions involving electron transfer in solution is presented. The assumption of ``slight-overlap'' is shown to lead to a reaction path which involves an intermediate state X* in which the electrical polarization of the solvent does not have the usual value appropriate for the given ionic charges (i.e., it does not have an equilibrium value). Using an equation developed elsewhere for the electrostatic free energy of nonequilibrium states, the free energy of all possible intermediate states is calculated. The characteristics of the most probable state are then determined with the aid of the calculus of variations by minimizing its free energy subject to certain restraints. A simple expression for the electrostatic contribution to the free energy of formation of the intermediate state from the reactants, ΔF*, is thereby obtained in terms of known quantities, such as ionic radii, charges, and the standard free energy of reaction. This intermediate state X* can either disappear to reform the reactants, or by an electronic jump mechanism to form a state X in which the ions are characteristic of the products. When the latter process is more probable than the former, the over-all reaction rate is shown to be simply the rate of formation of the intermediate state, namely the collision number in solution multiplied by exp(—ΔF*/kT). Evidence in favor of this is cited. In a detailed quantitative comparison, given elsewhere, with the kinetic data, no arbitrary parameters are needed to obtain reasonable agreement of calculated and experimental results.

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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Wittig olefination reaction and modifications involving phosphoryl-stabilized carbanions. Stereochemistry, mechanism, and selected synthetic aspectsBruce E. Maryanoff and Allen B. ReitzCite this: Chem. Rev. 1989, 89, 4, 863–927Publication Date (Print):June 1, 1989Publication History Published online1 May 2002Published inissue 1 June 1989https://doi.org/10.1021/cr00094a007RIGHTS & PERMISSIONSArticle Views26883Altmetric-Citations2157LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (9 MB) Get e-Alerts Get e-Alerts

Reduction of an electron acceptor (oxidant), A, or oxidation of an electron donor (reductant), A2−, is often achieved stepwise via one-electron processes involving the couples A/A⋅− or A⋅−/A2− (or corresponding prototropic conjugates such as A/AH⋅ or AH⋅/AH2). The intermediate A⋅−(AH⋅) is a free radical. The reduction potentials of such one-electron couples are of value in predicting the direction or feasibility, and in some instances the rate constants, of many free-radical reactions. Electrochemical methods have limited applicability in measuring these properties of frequently unstable species, but fast, kinetic spectrophotometry (especially pulse radiolysis) has widespread application in this area. Tables of ca. 1200 values of reduction potentials of ca. 700 one-electron couples in aqueous solution are presented. The majority of organic oxidants listed are quinones, nitroaryl and bipyridinium compounds. Reductants include phenols, aromatic amines, indoles and pyrimidines, thiols and phenothiazines. Inorganic couples largely involve compounds of oxygen, sulfur, nitrogen and the halogens. Proteins, enzymes and metals and their complexes are excluded.

Amy K. Smith, Ruth N. Bolton, Janet Wagner, A Model of Customer Satisfaction with Service Encounters Involving Failure and Recovery, Journal of Marketing Research, Vol. 36, No. 3 (Aug., 1999), pp. 356-372

British Journal of Pharmacology (BJP) is pleased to publish a new set of guidelines for reporting research involving animals, simultaneously with several other journals; the 'ARRIVE' guidelines (Animals in Research: Reporting In Vivo Experiments). This editorial summarizes the background to the guidelines, gives our view of their significance, considers aspects of specific relevance to pharmacology, re-states BJP's guidelines for authors on animal experiments and indicates our commitment to carrying on discussion of this important topic. We also invite feedback via the British Pharmacological Society website.

G. Hanoch, H. Levy; The Efficiency Analysis of Choices Involving Risk1, The Review of Economic Studies, Volume 36, Issue 3, 1 July 1969, Pages 335–346, htt

Journal Article A sarcoma involving the jaws in african children Get access Denis Burkitt Denis Burkitt Department of Surgery, Makerere College Medical School, and Mulago Hospital, Kampala, Uganda Search for other works by this author on: Oxford Academic Google Scholar British Journal of Surgery, Volume 46, Issue 197, November 1958, Pages 218–223, https://doi.org/10.1002/bjs.18004619704 Published: 06 December 2005

A fundamental change has been achieved in understanding surface electrochemistry due to the profound knowledge of the nature of electrocatalytic processes accumulated over the past several decades and to the recent technological advances in spectroscopy and high resolution imaging. Nowadays one can preferably design electrocatalysts based on the deep theoretical knowledge of electronic structures, via computer-guided engineering of the surface and (electro)chemical properties of materials, followed by the synthesis of practical materials with high performance for specific reactions. This review provides insights into both theoretical and experimental electrochemistry toward a better understanding of a series of key clean energy conversion reactions including oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The emphasis of this review is on the origin of the electrocatalytic activity of nanostructured catalysts toward the aforementioned reactions by correlating the apparent electrode performance with their intrinsic electrochemical properties. Also, a rational design of electrocatalysts is proposed starting from the most fundamental aspects of the electronic structure engineering to a more practical level of nanotechnological fabrication.

Abstract This paper is concerned with the evaluation and tabulation of certain integrals of the type (* 00 I(p, v; A) = J J fa t) ) e~cttxdt. In part I of this paper, a formula is derived for the integrals in terms of an integral of a hypergeometric function. This new integral is evaluated in the particular cases which are of most frequent use in mathematical physics. By means of these results, approximate expansions are obtained for cases in which the ratio b/a is small or in which b~a and is small. In part II, recurrence relations are developed between integrals with integral values of the parameters pt, v and A. Tables are given by means of which 7(0, 0; 1), 7(0, 1; 1), 7(1, 0; 1), 7(1,1; 1), 7(0, 0 ;0), 7(1, 0;'0), 7(0, 1; 0), 7(1, 1; 0), 7(0,1; - 1 ), 7(1,0; - 1 ) and 7(1,1; - 1 ) may be evaluated for 0 < b/a ^ 2, 0 ^ c/a ^ 2.

Adopted by the 18th WMA General Assembly, Helsinki, Finland, June 1964; amended by the 29th WMA General Assembly, Tokyo, Japan, October 1975; 35th WMA General Assembly, Venice, Italy, October 1983; 41st WMA General Assembly, Hong Kong, September 1989; 48th WMA General Assembly, Somerset West, Republic of South Africa, October 1996, and the 52nd WMA General Assembly, Edinburgh, Scotland, October 2000.

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Adopted by the 18th WMA General Assembly Helsinki, Finland, June 1964 and amended by the 29th WMA General Assembly, Tokyo, Japan, October 1975; 35th WMA General Assembly, Venice, Italy, October 1983; 41st WMA General Assembly, Hong Kong, September 1989; 48th WMA General Assembly, Somerset West, Republic of South Africa, October 1996 and the 52nd WMA General Assembly, Edinburgh, Scotland, October 2000

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Most human diseases are complex multi-factorial diseases resulting from the combination of various genetic and environmental factors. In the KEGG database resource (http://www.genome.jp/kegg/), diseases are viewed as perturbed states of the molecular system, and drugs as perturbants to the molecular system. Disease information is computerized in two forms: pathway maps and gene/molecule lists. The KEGG PATHWAY database contains pathway maps for the molecular systems in both normal and perturbed states. In the KEGG DISEASE database, each disease is represented by a list of known disease genes, any known environmental factors at the molecular level, diagnostic markers and therapeutic drugs, which may reflect the underlying molecular system. The KEGG DRUG database contains chemical structures and/or chemical components of all drugs in Japan, including crude drugs and TCM (Traditional Chinese Medicine) formulas, and drugs in the USA and Europe. This database also captures knowledge about two types of molecular networks: the interaction network with target molecules, metabolizing enzymes, other drugs, etc. and the chemical structure transformation network in the history of drug development. The new disease/drug information resource named KEGG MEDICUS can be used as a reference knowledge base for computational analysis of molecular networks, especially, by integrating large-scale experimental datasets.

BACKGROUND: Meta-analysis of randomized controlled trials (RCTs) is usually based on trials where patients are randomized individually into two different, parallel, treatment groups. This paper concentrates on RCTs of a different design-two-period, two-treatment cross-over trials. METHODS: The characteristics of these trials are outlined, with detailed examples of methods for analysis for both continuous and binary data. These case studies are then extended into the context of a meta-analysis. The Cochrane Library was surveyed to assess current practice for synthesis. RESULTS: Methods are described for continuous and binary data for use both when the necessary paired data are given and also when they need to be calculated or imputed, and some suggestions are provided to help people wishing to synthesize data from cross-over trials into meta-analyses. The survey suggested that about 8% of the trials in the Cochrane library were cross-over trials and 18% of the reviews referred to such trials, although there was no consistent approach to their inclusion into the reviews. CONCLUSIONS: Methods do exist for including valuable information from two-period, two-treatment cross-over trials into quantitative reviews. However, poor reporting of cross-over trials will often impede attempts to perform a meta-analysis using the available methods.

Abstract Advanced oxidation processes are defined as those which involve the generation of hydroxyl radicals in sufficient quantity to affect water purification. The theoretical and (practical yield of OH from O3 at high pH, 03/H202, O3/UV and H2O2/UV systems is reviewed. New data is presented which illustrates the importance of direct photolysis in the O3/UV process, the effect of the H202:03 ratio in the O3/H2O2 process, and the impact of the low extinction coefficient of H2O2 in the H202/UV process.