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Simple Methodology (simple + methodology)
Selected AbstractsSimple Methodology for Heck Arylation at C-8 of Adenine NucleosidesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2008Pallavi Lagisetty Abstract A simple method for the arylation of 8-vinyladenine nucleoside derivatives is reported. With a broad set of aryl iodides and bromides, the reaction is catalyzed by the simple combination palladium acetate/tris(o -tolyl)phosphine/triethylamine [Pd(OAc)2/(o -tol)3P/Et3N]. As expected, aryl chlorides are more difficult coupling partners but some undergo reactions with more exotic catalysts. Although trans -olefins are the major products, minor amounts of cis -isomers are detected in some cases, and a post -arylation mechanism for their formation is proposed. Finally, by subtle catalyst modulation chemoselective N -arylation of the nucleoside can be achieved in the presence of the vinyl moiety. [source] TOWARD GREENER DIALYSIS: A CASE STUDY TO ILLUSTRATE AND ENCOURAGE THE SALVAGE OF REJECT WATERJOURNAL OF RENAL CARE, Issue 2 2010Andrew Connor MRCP SUMMARY Climate change is now considered to be a major global public health concern. However, the very provision of health care itself has a significant impact upon the environment. Action must be taken to reduce this impact. Water is a precious and finite natural resource. Vast quantities of high-grade water are required to provide haemodialysis. The reverse osmosis systems used in the purification process reject approximately two-thirds of the water presented to them. Therefore, around 250 litres of ,reject water' result from the production of the dialysate required for one treatment. This good quality reject water is lost-to-drain in the vast majority of centres worldwide. Simple methodologies exist to recycle this water for alternative purposes. We describe here a case study of the only UK renal service we know to have implemented such water-saving methodologies. We outline the benefits in terms of financial and environmental savings. [source] Use of quasi-isoelectric buffers as anolyte and catholyte to improve capillary isoelectric focusing performancesELECTROPHORESIS, Issue 8 2008Martine Poitevin Abstract The use of quasi-isoelectric anolytes and catholytes has been investigated to improve CIEF performances. Narrow pH cuts of carrier ampholytes (NC) have been compared to more conventional couples of anolytes/catholytes (phosphoric acid/sodium hydroxide and glutamic acid/lysine). First, a CIEF setup that consists in a bare silica capillary and 70:30 water/glycerol separation medium has been used. The experiments have shown that when using NC instead of more classical anolytes and catholytes, an increase in the protein detection time was observed and the resolutions obtained for neutral and acidic proteins were doubled. Moreover, according to the NC fraction used, the resolution was modified. In order to investigate further the mechanisms involved, a second setup using a capillary coated with hydroxypropylcellulose was used. With this setup no difference has been observed when changing anolyte and catholyte nature. A simple methodology has then been developed to evaluate EOF during focusing and mobilization steps of CIEF experiments. It highlighted the crucial role played by EOF when using a bare silica capillary. EOF indeed decreased by 33% during mobilization step when using NC instead of classical anolytes and catholytes. [source] A gridded hourly precipitation dataset for Switzerland using rain-gauge analysis and radar-based disaggregationINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 12 2010Marc Wüest Abstract Rain gauges and weather radars both constitute important devices for operational precipitation monitoring. Gauges provide accurate yet spotty precipitation estimates, while radars offer high temporal and spatial resolution yet at a limited absolute accuracy. We propose a simple methodology to combine radar and daily rain-gauge data to build up a precipitation dataset with hourly resolution covering a climatological time period. The methodology starts from a daily precipitation analysis, derived from a dense rain-gauge network. A sequence of hourly radar analyses is then used to disaggregate the daily analyses. The disaggregation is applied such as to retain the daily precipitation totals of the rain-gauge analysis, in order to reduce the impact of quantitative radar biases. Hence, only the radar's advantage in terms of temporal resolution is exploited. In this article the disaggregation method is applied to derive a 15-year gridded precipitation dataset at hourly resolution for Switzerland at a spatial resolution of 2 km. Validation of this dataset indicates that errors in hourly intensity and frequency are lower than 25% on average over the Swiss Plateau. In Alpine valleys, however, errors are typically larger due to shielding effects of the radar and the corresponding underestimation of precipitation periods by the disaggregation. For the flatland areas of the Swiss Plateau, the new dataset offers an interesting quantitative description of high-frequency precipitation variations suitable for climatological analyses of heavy events, the evaluation of numerical weather forecasting models and the calibration/operation of hydrological runoff models. Copyright © 2009 Royal Meteorological Society [source] Humidity parameters from temperature: test of a simple methodology for European conditionsINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 7 2008Yvonne Andersson-Sköld Abstract Atmospheric water content is important for local and regional climate, and for chemical processes of soluble and solute species in the atmosphere. Further, vapour pressure deficit (D) is one of the key controls on the opening of stomata in plants and is thus an important force for evapotransporation, plant respiration and biomass production and for the uptake of harmful pollutants such as ozone through the stomata. Most meteorological stations typically measure both temperature and relative humidity (RH). However, even if recorded at finer time resolution, it is usually the daily or often monthly means of RH which are published in climate reports. Unfortunately, such data cannot be used to obtain the changes in RH or vapour pressure deficit over the day, as this depends strongly on the diurnal temperature variation during the day and not upon the mean temperature. Although RH typically changes significantly over the day, the ambient vapour pressure is often remarkably constant. Here a simple method to estimate diurnal vapour pressure is evaluated, based upon an assumed constant vapour pressure, and that recorded minimum temperatures approximate dew-point temperatures. With a knowledge of only temperature, we will show that day to day estimates of vapour pressure, humidity and especially D, can be made with reasonable accuracy. This methodology is tested using meteorological data from 32 sites covering a range of locations in Europe. Such a simple methodology may be used to extract approximate diurnal curves of vapour pressures from published meteorological data which contains only minimum temperatures for each day, or where humidity data are not available. Copyright © 2007 Royal Meteorological Society [source] Studies on some singular potentials in quantum mechanicsINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 6 2005Amlan K. RoyArticle first published online: 10 MAY 200 Abstract A simple methodology is suggested for the efficient calculation of certain central potentials having singularities. The generalized pseudospectral method used in this work facilitates nonuniform and optimal spatial discretization. Applications have been made to calculate the energies, densities, and expectation values for two singular potentials of physical interest, viz., (i) the harmonic potential plus inverse quartic and sextic perturbation and (ii) the Coulomb potential with a linear and quadratic term for a broad range of parameters. The first 10 states belonging to a maximum of ,, = 8 and 5 for (i) and (ii) have been computed with good accuracy and compared with the most accurate available literature data. The calculated results are in excellent agreement, especially in light of the difficulties encountered in these potentials. Some new states are reported here for the first time. This offers a general and efficient scheme for calculating these and other similar potentials of physical and mathematical interest in quantum mechanics accurately. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 [source] Attorney Fees in Class Action Settlements: An Empirical StudyJOURNAL OF EMPIRICAL LEGAL STUDIES, Issue 1 2004Theodore Eisenberg Study of two comprehensive class action case data sets covering 1993,2002 shows that the amount of client recovery is overwhelmingly the most important determinant of the attorney fee award. Even in cases in which the courts engage in the lodestar calculation (the product of reasonable hours and a reasonable hourly rate), the client's recovery generally explains the pattern of awards better than the lodestar. Thus, the time and expense of a lodestar calculation may be wasteful. We also find no robust evidence that either recoveries for plaintiffs or fees of their attorneys increased over time. The mean fee award in common fund cases is well below the widely quoted one-third figure, constituting 21.9 percent of the recovery across all cases for a comprehensive data set of published cases. A scaling effect exists: fees constitute a lower percent of the client's recovery as the client's recovery increases. Fees are also correlated with risk: the presence of high risk is associated with a higher fee, while low-risk cases generate lower fees. Fees as a percent of class recovery were found to be higher in federal than state court. The presence of "soft" relief (such as injunctive relief or coupons) has no material effect on the fee, regardless of whether the soft relief was included in the quantified benefit for the class used as the basis for computing the attorney fee. The study also addresses costs and expenses. Like fees, these display significant scale effects. The article proposes a simple methodology by which courts can evaluate the reasonableness of fee requests. [source] Integrated approach to optimization of an ultrasonic processorAICHE JOURNAL, Issue 11 2003Vijayanand S. Moholkar In an ultrasonic processor, the input electrical energy undergoes many transformations before getting converted into the cavitation energy, which is dissipated in the medium to bring out the physical/chemical change. An investigation of the influence of free and dissolved gas content of the system on the efficiency of this energy transformation chain is attempted. The results of the experiments reveal that the cavitation intensity produced in the medium varies significantly with the gas content of the system. A unified physical model, which combines basic theories of acoustics and bubble dynamics, has been used to explain the experimental results. An attempt has been made to establish the mechanism of the steps in the energy transformation chain, the involved physical parameters, and interrelations between them. It has been found that the influence of free and dissolved gas content of the medium on the overall energy transformation occurs through a complex inter-dependence of several parameters. Thus, simultaneous optimization of individual steps in the energy transformation chain, with an integrated approach, is necessary for the optimization of an ultrasonic processor. The present study puts forth a simple methodology, with the gas content of the system as manipulation parameter, for this purpose. [source] Using limiting factors analysis to overcome the problem of long time horizonsNEW DIRECTIONS FOR EVALUATION, Issue 122 2009Raymond Gullison In recent years, donors to biodiversity conservation projects have sought greater accountability, using professional evaluators to help assess the degree to which grantees are achieving conservation objectives. One of the most formidable challenges evaluators face is the time required both for ecological systems to respond to management interventions and over which grantees must maintain their biodiversity conservation gains. The authors present a simple methodology, called limiting factors analysis, which was developed during the course of evaluating several large portfolios of conservation projects. The method is a practical basis for rapidly assessing whether current conditions are likely to prevent grantees from achieving their long-term objectives. Use of the methodology is illustrated with examples from recent evaluations of the Andes Amazon Initiative and the Columbia Basin Water Transactions Program. © Wiley Periodicals, Inc. [source] Gas-phase fragmentation study of novel synthetic 1,5-benzodiazepine derivatives using electrospray ionization tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 14 2008Mohamed Rida The fragmentation patterns of a series of three novel synthesized 3-hydroxy-4-phenyl-tetrahydro-1,5-benzodiazepin-2-ones (1,3), possessing the same backbone structure, were investigated using electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (MS/MS) techniques. A simple methodology, based on the use of ESI (positive ion mode) and by increasing the declustering potential in the atmospheric pressure/vacuum interface, collision-induced dissociation (CID), was used to enhance the formation of the fragment ions. In general, the novel synthetic 1,5-benzodiazepine derivatives afforded, in the gas phase, both protonated and sodiated molecules. This led to the confirmation of the molecular masses and chemical structures of the studied compounds. Exact accurate masses were measured using a high-resolution ESI-quadrupole orthogonal time-of-flight (QqToF)-MS/MS hybrid mass spectrometer instrument. The breakdown routes of the protonated molecules were rationalized by conducting low-energy collision CID-MS/MS analyses (product ion- and precursor ion scans) using a conventional quadrupole-hexapole-quadrupole (QhQ) tandem mass spectrometer. All the observed major fragmentations for the 1,5-benzodiazepines occurred in the saturated seven-membered ring containing the nitrogen atoms. These formed a multitude of product ions by different breakdown routes. All the major fragmentations involved cleavages of the N -1,C -2 andC -3,C -4 bonds. These occurred with concomitant eliminations of glyoxal, benzene and ethyl formate, forming the product ion at m/z 119, which was observed in all the studied compounds. In addition, an unique simultaneous CID-MS/MS fragmentation was noticed for the 1,5-benzodiazepines 1 and 3, which occurred by a pathway dictated by the substituent located on the N -1-position. It was evident that the aromatic ring portion of the 1,5-benzodiazepines was resistant to CID-MS/MS fragmentation. Re-confirmation of the various geneses of the product ions was achieved by conducting a series of precursor ion scans. ESI-MS and CID-MS/MS analyses have thus proven to be a specific and very sensitive method for the structural identification of these novel 1,5-benzodiazepine derivatives. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||