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Modular Approach (modular + approach)
Selected AbstractsA Modular Approach to a New Class of Monodentate Chiral Phosphorus Ligands and Their Application in Enantioselective Copper-Catalysed Conjugate Additions of Diethylzinc to CyclohexenoneEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 16 2004Chiara Monti Abstract A new family of chiral phosphorus ligands (5) for use in enantioselective catalysis have been synthesised. The ligands contain the electron-poor bis(sulfonyl)diazaphospholidine moiety and possess a highly modular structure which is well suited to the synthesis of a library. A small library (23 members) of ligands 5 was prepared and tested in the enantioselective copper-catalysed conjugate addition of diethylzinc to cyclohexenone. Complete conversions were obtained with enantiomeric excesses (ee) of up to 75%. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] A Modular Approach to ,-Arylated Carbonyl Compounds via Indium Tris(bistriflylamide)-Catalyzed Regioselective Addition of ,-Ketoesters to 1,3-DiynesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-13 2005Masaharu Nakamura Abstract A modular synthesis of ,-arylated carbonyl compounds has been achieved by the combination of an indium-catalyzed regioselective addition of ,-keto esters to conjugated diynes and a palladium-catalyzed benzannulation reaction. Indium tris(bistriflylamide), In(NTf2)3, was found to be an efficient catalyst for the first addition reaction of ,-keto esters to diynes. The reaction proceeds with perfect regioselectivity to give conjugated enynes in high yield. The second palladium-catalyzed benzannulation proceeds in high to excellent yield and with high regioselectivity for a variety of diynes. This two-step ,-arylation of carbonyl compounds thus proceeds in a catalytic manner without loss of elements in the starting materials. The reaction may be performed in a single pot without isolation of the product of the first step. [source] A Modular Approach to Functionalized and Expanded Crown Ether Based Macrocycles Using Click Chemistry,ANGEWANDTE CHEMIE, Issue 36 2009Sandra Binauld Maßgeschneiderte Fesseln: ,-Azid-,-Alkin-Oligomere entstehen in hoher Ausbeute durch Kupfer(I)-katalysierte Azid-Alkin-Cycloaddition (CuAAC), iteratives Kettenwachstum und Schützen-Entschützen-Strategien. Eine intramolekulare CuAAC unter pseudohoher Verdünnung liefert dann Makrocyclen mit n = 1,8 Triazoleinheiten im Cyclus (im Bild ist der Fall n=2 gezeigt; C,grau, O,rot, N,blau, H,weiß). [source] Labeling Tetracysteine-Tagged Proteins with a SplAsH of Color: A Modular Approach to Bis-Arsenical FluorophoresCHEMBIOCHEM, Issue 14 2007Anjan K. Bhunia Dr. Everything nicely tied up. We have synthesized a non-fluorescent bis-arsenical targeting moiety that can be tethered to a wide variety of different fluorescent payloads. This strategy greatly broadens the scope of dyes that can be used to label tetracysteine-tagged proteins. [source] A Modular Approach for the Synthesis of Dibenzoazepine Derivatives.CHEMINFORM, Issue 12 2007Gerhard Hilt Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Palladium-Catalyzed Multicomponent Coupling of Alkynes, Imines, and Acid Chlorides: A Direct and Modular Approach to Pyrrole Synthesis.CHEMINFORM, Issue 22 2004Rajiv Dhawan Abstract For Abstract see ChemInform Abstract in Full Text. [source] Autoassociator networks: insights into infant cognitionDEVELOPMENTAL SCIENCE, Issue 2 2004Sylvain Sirois This paper presents autoassociator neural networks. A first section reviews the architecture of these models, common learning rules, and presents sample simulations to illustrate their abilities. In a second section, the ability of these models to account for learning phenomena such as habituation is reviewed. The contribution of these networks to discussions about infant cognition is highlighted. A new, modular approach is presented in a third section. In the discussion, a role for these learning models in a broader developmental framework is proposed. [source] Spatial prediction of river channel topography by krigingEARTH SURFACE PROCESSES AND LANDFORMS, Issue 6 2008Carl J. Legleiter Abstract Topographic information is fundamental to geomorphic inquiry, and spatial prediction of bed elevation from irregular survey data is an important component of many reach-scale studies. Kriging is a geostatistical technique for obtaining these predictions along with measures of their reliability, and this paper outlines a specialized framework intended for application to river channels. Our modular approach includes an algorithm for transforming the coordinates of data and prediction locations to a channel-centered coordinate system, several different methods of representing the trend component of topographic variation and search strategies that incorporate geomorphic information to determine which survey data are used to make a prediction at a specific location. For example, a relationship between curvature and the lateral position of maximum depth can be used to include cross-sectional asymmetry in a two-dimensional trend surface model, and topographic breaklines can be used to restrict which data are retained in a local neighborhood around each prediction location. Using survey data from a restored gravel-bed river, we demonstrate how transformation to the channel-centered coordinate system facilitates interpretation of the variogram, a statistical model of reach-scale spatial structure used in kriging, and how the choice of a trend model affects the variogram of the residuals from that trend. Similarly, we show how decomposing kriging predictions into their trend and residual components can yield useful information on channel morphology. Cross-validation analyses involving different data configurations and kriging variants indicate that kriging is quite robust and that survey density is the primary control on the accuracy of bed elevation predictions. The root mean-square error of these predictions is directly proportional to the spacing between surveyed cross-sections, even in a reconfigured channel with a relatively simple morphology; sophisticated methods of spatial prediction are no substitute for field data. Copyright © 2007 John Wiley & Sons, Ltd. [source] A modular approach to addressing model design, scale, and parameter estimation issues in distributed hydrological modellingHYDROLOGICAL PROCESSES, Issue 2 2002G. H. Leavesley Abstract A modular approach to model design and construction provides a flexible framework in which to focus the multidisciplinary research and operational efforts needed to facilitate the development, selection, and application of the most robust distributed modelling methods. A variety of modular approaches have been developed, but with little consideration for compatibility among systems and concepts. Several systems are proprietary, limiting any user interaction. The US Geological Survey modular modelling system (MMS) is a modular modelling framework that uses an open source software approach to enable all members of the scientific community to address collaboratively the many complex issues associated with the design, development, and application of distributed hydrological and environmental models. Implementation of a common modular concept is not a trivial task. However, it brings the resources of a larger community to bear on the problems of distributed modelling, provides a framework in which to compare alternative modelling approaches objectively, and provides a means of sharing the latest modelling advances. The concepts and components of the MMS are described and an example application of the MMS, in a decision-support system context, is presented to demonstrate current system capabilities. Copyright © 2002 John Wiley & Sons, Ltd. [source] FOX, `free objects for crystallography': a modular approach to ab initio structure determination from powder diffractionJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 6 2002Vincent Favre-Nicolin A new program has been developed for ab initio crystal structure determination from powder diffraction data (X-ray and neutron). It uses global-optimization algorithms to solve the structure by performing trials in direct space. It is a modular program, capable of using several criteria for evaluating each trial configuration (e.g. multi-pattern). It is also modular in the description of the crystal content, with the possibility of describing building blocks in the sample, such as polyhedra or molecules, and with automatic adaptive handling of special positions and sharing of identical atoms between neighbouring building blocks. It can therefore find the correct structure without any assumption about the connectivity of the building blocks and is suitable for any kind of material. Several optimization algorithms (simulated annealing, parallel tempering) are available, with the possibility of choosing the convergence criterion as a combination of available cost functions. This program is freely available for Linux and Windows platforms; it is also fully `open source', which, combined with an object-oriented design and a complete developer documentation, ensures its future evolution. [source] A general strategy for highly efficient nanoparticle dispersing agents based on hybrid dendritic linear block copolymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2009Robert Vestberg Abstract A modular approach to the synthesis of a library of hybrid dendritic-linear copolymers was developed based on RAFT polymerization from monodisperse dendritic macroRAFT agents. By accurately controlling the molecular weight of the linear block, generation number of the dendrimer and the nature of the dendritic chains ends, the performance of these hybrid block copolymers as dispersing agents was optimized for a range of nanoparticles. For titanium dioxide nanoparticles, dispersion in a poly(methyl methacrylate) matrix was maximized with a second generation dendrimer containing four carboxylic acid end groups, and the quality of dispersion was observed to be superior to commercial dispersing agents for TiO2. This approach also allowed novel hybrid dendritic-linear dispersing agents to be prepared for the dispersion of Au and CdSe nanoparticles based on disulphide and phosphine oxide end groups, respectively. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1237,1258, 2009 [source] PUBLIC SERVICE PERSPECTIVES ON REFORMS OF ELECTRICITY DISTRIBUTION AND SUPPLY: A MODULAR ANALYSISANNALS OF PUBLIC AND COOPERATIVE ECONOMICS, Issue 2 2010Ute Dubois ABSTRACT,:,This article analyzes organizational change in electricity distribution and retail businesses and its impact on public service issues. Organizational change has resulted from the European electricity directives, especially the EU Electricity directive 2003/54/EC, which has imposed major transformations on these activities, requiring legal unbundling of electricity distribution networks by 1 July 2007. Organizational change has also resulted from an adaptation of companies to the newly competitive environment. This has led to a diversity of organizational choices across Europe. We analyze this diversity by using a modular approach, which decomposes reforms in electricity distribution and retail into logical ,blocks'. We then examine how European countries have dealt with two policy and regulatory issues related to customer protection in that new environment: the regulation of quality of distribution, which is a task of regulators, and energy affordability policies for vulnerable customers, which are a central aspect of public service policies in the electricity sector. [source] Effect of an Integrated Public Health Curriculum in an Emergency Medicine ResidencyACADEMIC EMERGENCY MEDICINE, Issue 2009Marian Betz Background: Emergency departments (EDs) serve as a central point of interaction between the public and the medical system. Emergency physicians need education in public health in order to optimize their clinical care and their ability to evaluate potential public health interventions in the ED. Methods: As part of the Centers for Disease Control and Prevention (CDC) and the Association of American Medical College's (AAMC) national initiative for "Regional Medicine-Public Health Education Centers-Graduate Medical Education", we designed and implemented a new public health curriculum for the emergency medicine residents. Over four sessions during regular didactic time, we used a modular approach to link a basic public health principle, such as environmental hazard assessment, to a relevant clinical topic, such as violent patients and ED safety. Each session emphasized resident involvement, including small group work and role-plays. Journal clubs and quality assurance projects supplemented the curriculum. We sought resident feedback through focus groups and anonymous online pre- and post-tests for each session. Assessment: Both before and after the curriculum, 76% of responders felt it was important for physicians to receive training in public health. The program appeared to have a positive effect on residents' comfort level with various public health topics, and felt the residency program had taught them the skills necessary to implement public health principles in clinical practice (23.8%, versus 11.5% before; p<0.05). Conclusions: Integration of public health principles into existing clinical curricula in emergency medicine may increase resident interest and knowledge. Combining public health and emergency medicine topics in regular didactic conferences facilitates public health education for residents. [source] Formal Synthesis of the Anti-Angiogenic Polyketide (,)-Borrelidin under Asymmetric Catalytic ControlCHEMISTRY - A EUROPEAN JOURNAL, Issue 38 2010Ashoka V. R. Madduri Abstract Borrelidin (1) is a polyketide that possesses extremely potent anti-angiogenesis activity. This paper describes its formal total synthesis by the most efficient route to date. This modular approach takes optimal benefit of asymmetric catalysis and permits the synthesis of analogues; in addition, the high yields and selectivities obtained eliminate the need for separation of stereoisomers. The upper half of borrelidin has been accessed by iterative copper-catalysed asymmetric conjugate addition of methylmagnesium bromide, whereas synthesis of the lower half of the molecule was achieved by relying on asymmetric hydrogenation and cross-methathesis as key steps. [source] Direct Electrochemistry of Cytochrome,c at Modified Si(100) ElectrodesCHEMISTRY - A EUROPEAN JOURNAL, Issue 20 2010Simone Ciampi Abstract This paper demonstrates the direct electron transfer between the heme moiety of horse hearth cytochrome,c and a pyridinyl group on self-assembled-monolayer-modified Si(100) electrodes. Self-assembled monolayers (SAMs) containing the putative receptor ligand were prepared by a step-wise procedure using "click" reactions of acetylene-terminated alkyl monolayers and isonicotinic acid azide derivatives. Unoxidized Si(100) electrodes, possessing either isonicotinate or isonicotinamide receptor ligands, were characterized using X-ray photoelectron spectroscopy, contact-angle goniometry, cyclic voltammetry, and electrochemical impedance spectroscopy. The ability of isonicotinic acid terminated layers to coordinatively bind the redox center of cytochrome,c was found to be restricted to pyridinyl assemblies with a para -ester linkage present. The protocol detailed here offers an experimentally simple modular approach to producing chemically well-defined SAMs on silicon surfaces for direct electrochemistry of a well-studied model redox protein. [source] A New Class of Non-Racemic Chiral Macrocycles: A Conformational and Synthetic StudyCHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2005Susan E. Gibson Prof. Abstract Amino alcohols have been used to introduce non-racemic chirality into macrocycles using a modular approach that relies on a Heck macrocyclisation reaction. A wide variety of macrocycles have been synthesised, and their structures studied using X-ray crystallography and molecular modelling. A fragmentation reaction encountered during the use of (S)-1,1-dimethylvalinol revealed that carboxylic acids generate acylals under reaction conditions often used for Heck reactions. [source] A modular approach to addressing model design, scale, and parameter estimation issues in distributed hydrological modellingHYDROLOGICAL PROCESSES, Issue 2 2002G. H. Leavesley Abstract A modular approach to model design and construction provides a flexible framework in which to focus the multidisciplinary research and operational efforts needed to facilitate the development, selection, and application of the most robust distributed modelling methods. A variety of modular approaches have been developed, but with little consideration for compatibility among systems and concepts. Several systems are proprietary, limiting any user interaction. The US Geological Survey modular modelling system (MMS) is a modular modelling framework that uses an open source software approach to enable all members of the scientific community to address collaboratively the many complex issues associated with the design, development, and application of distributed hydrological and environmental models. Implementation of a common modular concept is not a trivial task. However, it brings the resources of a larger community to bear on the problems of distributed modelling, provides a framework in which to compare alternative modelling approaches objectively, and provides a means of sharing the latest modelling advances. The concepts and components of the MMS are described and an example application of the MMS, in a decision-support system context, is presented to demonstrate current system capabilities. Copyright © 2002 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||