688 resultados para ESI
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"Ezhemi͡esi͡achnik dlia iskusstva i staring."
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Includes historical and critical material.
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Editors: 1891- D. A. Henik and f. K. Flemming.
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The synthesis of the hexadentate ligand 5,6-dimethyl-2,2,9,9-tetra(methyleneamine)-4,7-dithiadecane (1,2-Me(2)EtN(4)S(2)amp) is reported. The diastereiosomers were separated as cobalt(III) complexes using cation exchange chromatography. The rac and mesa isomers were characterized by NMR (C-13, H-1, Co-59), ESI-MS, UV-Vis spectroscopy and cyclic voltammetry. Single crystals of [Co(rac-1,2-Me(2)EtN(4)S(2)amp)] Cl-2(ClO4) (.) 2H(2)O were characterized by X-ray diffraction. The low-temperature (11 K) absorption spectra of the complexes have been measured in Nafion films and from the observed positions of both spin-allowed (1)A(1g) --> T-1(1g) and (1)A(1g) --> T-1(2g) and spin forbidden (1)A(1g) --> T-3(2g) bands, octahedral ligand-field parameters (10Dq, B and C) were determined. These results, in conjunction with the Co-59 NMR data, are used to further explore the relationship between the Co-59 magnetogyric ratio (gamma(Co)) and the product of the nephelauxetic ratio and the wavelength of the (1)A(1g) --> T-1(1g) transition (beta(DeltaE)(-1)) for complexes of mixed donor nitrogen-thioether ligands. (C) 2004 Elsevier Ltd. All rights reserved.
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Complexation of cadmium(II) by the ditopic (bis-tridentate) thiocarbazone ligand 1,5-bis(6-methyl-2-pyridylmethylene) thiocarbonohydrazide, H2L1, results in the self-assembly of a charge-neutral 2 x 2 molecular grid, [Cd-4(L-1)(4)], comprising four metals and four ligands in an interlocked cyclic array. The solid-state structure of this tetramer has been established by X-ray crystallography and in solution by H-1 NMR spectroscopy. The presence of lower molecular weight oligomers was identified by both NMR and ESI-MS.
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Novel 2:2-macrocycles bearing bridged concave 2,6,9-trioxabicyclo[3.3.1]nona-3,7-dienes as chiral spacer units were obtained by cyclocondensation reaction of the chiral bisacid chloride and the corresponding diols, while use of methylene diamines instead of diols afforded 1:1 macrocycles only. Applying the same, but now template-assisted, experimental procedure to the reaction of the bisacid chloride with triethylene glycol brought about a significant increase in yield as well as a suitable simplification of the work-up during preparation and separation of the corresponding 1:1 as well as 2:2 macrocycles, when compared to results reported previously. HPLC separation on chiral columns revealed the presence of diastereoisomers [RR(S,S)- and RS-(meso)-forms] for all 2:2 macrocycles, which was further evidenced by the CD spectrum of one of those species as an example. Preliminary ESI-MS experiments indicated strong complexation abilities of the sulphur-containing ligand towards Ag(I), Cu(II) and Au(III) ions.
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Enterprise systems interoperability (ESI) is an important topic for business currently. This situation is evidenced, at least in part, by the number and extent of potential candidate protocols for such process interoperation, viz., ebXML, BPML, BPEL, and WSCI. Wide-ranging support for each of these candidate standards already exists. However, despite broad acceptance, a sound theoretical evaluation of these approaches has not yet been provided. We use the Bunge-Wand-Weber (BWW) models, in particular, the representation model, to provide the basis for such a theoretical evaluation. We, and other researchers, have shown the usefulness of the representation model for analyzing, evaluating, and engineering techniques in the areas of traditional and structured systems analysis, object-oriented modeling, and process modeling. In this work, we address the question, what are the potential semantic weaknesses of using ebXML alone for process interoperation between enterprise systems? We find that users will lack important implementation information because of representational deficiencies; due to ontological redundancy, the complexity of the specification is unnecessarily increased; and, users of the specification will have to bring in extra-model knowledge to understand constructs in the specification due to instances of ontological excess.
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The multiheme SoxAX proteins are notable for their unusual heme ligation (His/Cys-persulfide in the SoxA subunit) and the complexity of their EPR spectra. The diheme SoxAX protein from Starkeya novella has been expressed using Rhodobacter capsulatus as a host expression system. rSoxAX was correctly formed in the periplasm of the host and contained heme c in similar amounts as the native SoxAX. ESI-MS showed that the full length rSoxA, in spite of never having undergone catalytic turnover, existed in several forms, with the two major forms having masses of 28 687 +/- 4 and 28 718 +/- 4 Da. The latter form exceeds the expected mass of rSoxA by 31 4 Da, a mass close to that of a sulfur atom and indicating that a fraction of the recombinant protein contains a cysteine persulfide modification. EPR spectra of rSoxAX contained all four heme-dependent EPR signals (LS1a, LS1b, LS2, LS3) found in the native SoxAX proteins isolated from bacteria grown under sulfur chemolithotrophic conditions. Exposure of the recombinant SoxAX to different sulfur compounds lead to changes in the SoxA mass profile as determined by ESI while maintaining a fully oxidized SoxAX visible spectrum. Thiosulfate, the proposed SoxAX substrate, did not cause any mass changes while after exposure to dimethylsulfoxide a + 112 +/- 4 Da form of SoxA became dominant in the mass spectrum. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
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An assay using high performance liquid chromatography (HPLC)-electrospray ionization-tandem mass spectrometry (ESI-MS-MS) was developed for simultaneously determining concentrations of morphine, oxycodone, morphine-3-glucuronide, and noroxycodone, in 50 mul samples of rat serum. Deuterated (d(3)) analogues of each compound were used as internal standards. Samples were treated with acetonitrile to precipitate plasma proteins: acetonitrile was removed from the supernatant by centrifugal evaporation before analysis. Limits of quantitation (ng/ml) and their between-day accuracy and precision (%deviation and %CV) were-morphine, 3.8 (4.3% and 7.6%); morphine-3-glucuronide, 5.0 (4.5% and 2.9%); oxycodone, 4.5 (0.4% and 9.3%); noroxycodone, 5.0 (8.5% and 4.6%). (C) 2004 Elsevier B.V. All rights reserved.
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High-performance liquid chromatography coupled by an electrospray ion source to a tandem mass spectrometer (HPLC-EST-MS/ MS) is the current analytical method of choice for quantitation of analytes in biological matrices. With HPLC-ESI-MS/MS having the characteristics of high selectivity, sensitivity, and throughput, this technology is being increasingly used in the clinical laboratory. An important issue to be addressed in method development, validation, and routine use of HPLC-ESI-MS/MS is matrix effects. Matrix effects are the alteration of ionization efficiency by the presence of coeluting substances. These effects are unseen in the chromatograrn but have deleterious impact on methods accuracy and sensitivity. The two common ways to assess matrix effects are either by the postextraction addition method or the postcolumn infusion method. To remove or minimize matrix effects, modification to the sample extraction methodology and improved chromatographic separation must be performed. These two parameters are linked together and form the basis of developing a successful and robust quantitative HPLC-EST-MS/MS method. Due to the heterogenous nature of the population being studied, the variability of a method must be assessed in samples taken from a variety of subjects. In this paper, the major aspects of matrix effects are discussed with an approach to address matrix effects during method validation proposed. (c) 2004 The Canadian Society of Clinical Chemists. All rights reserved.
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Investigations into the kinetics and mechanism of dithiobenzoate-mediated Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerizations, which exhibit nonideal kinetic behavior, such as induction periods and rate retardation, are comprehensively reviewed. The appreciable uncertainty in the rate coefficients associated with the RAFT equilibrium is discussed and methods for obtaining RAFT-specific rate coefficients are detailed. In addition, mechanistic studies are presented, which target the elucidation of the fundamental cause of rate retarding effects. The experimental and theoretical data existing in the literature are critically evaluated and apparent discrepancies between the results of different studies into the kinetics of RAFT polymerizations are discussed. Finally, recommendations for further work are given. (c) 2006 Wiley Periodicals, Inc.
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O câncer em crianças até cerca de duas décadas, era considerado uma doença crônica, com prognóstico desfavorável, resultando na maioria dos casos, em morte. Atualmente, tem-se apresentado como uma doença com melhores perspectivas, onde 70% das crianças acometidas por essa doença podem ser curadas, quando diagnosticadas precocemente, e tratadas em centros especializados¹. Este estudo teve como objetivo, avaliar a qualidade de vida e o stress de crianças e adolescentes com câncer, em remissão e recidiva. Trata-se de um estudo correlacional, quali-quantitativo, transversal. Foi desenvolvido no ambulatório de oncologia pediátrica da Faculdade de Medicina do ABC, e na enfermaria do Hospital Mário Covas. Contou com a colaboração de 40 sujeitos, com idades entre 06 a 14 anos, de ambos os sexos. Como instrumento para medir a qualidade de vida, foi utilizado o Child Health Questionnaire (CHQ-PF50), que possui 15 conceitos em saúde, abrangendo aspectos físicos e psicossociais e para medir o stress, a Escala de Stress Infantil (ESI), que tem como objetivo, avaliar o stress da criança, através de reações físicas e psicológicas. Os resultados indicaram que no domínio físico (PhS), as crianças em situação clínica de recidiva e remissão não apresentam diferenças significativas em relação às variáveis: qualidade de vida e stress, porém, no domínio psicossocial (PsS), houve diferença estatisticamente significante, indicando que os meninos apresentam melhor qualidade de vida e menor stress, se comparados com as meninas, mostrando que o emocional interfere nesse resultado.(AU)
INTERVENÇÕES LÚDICO-MUSICAIS FRENTE AO ESTRESSE DE CRIANÇAS ACOLHIDAS VÍTIMAS DE VIOLÊNCIA DOMÉSTICA
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Este estudo investiga o nível de estresse de crianças acolhidas vítimas de violência doméstica, antes e após intervenções lúdico-musicais em grupo, através de pesquisa exploratória descritiva de caráter quali-quantitativo. Caracteriza inicialmente a população da instituição, de 100 acolhidos, seu perfil sócio-demográfico, tipo de violência e motivo do acolhimento. Aplica a seguir, a Escala de Stress Infantil, ESI em 20 sujeitos, selecionados por conveniência. Realiza em seguida, intervenção com oito desses 20 participantes, também selecionados por conveniência, em oito sessões semanais, baseadas em técnicas de musicoterapia, que incluem relaxamento e atividades lúdicas, com abordagem winnicottiana. Ao final, realiza pós-teste da ESI nos 20 participantes. Os dados do perfil sócio-demográfico dos 100 acolhidos revelam 65% por cento do sexo feminino e 35% do masculino; faixa etária média de 6,66; violências sofridas por: negligência (52%); violência física (19%); dificuldade financeira (15%); abandono (12%); abuso sexual (2%). No pré-teste da ESI, foi constatado estresse em 80% dos casos, com predomínio nas meninas, sendo que o pós-teste não mostrou diferença significativa (p=0,944). A análise da intervenção mostrou-se positiva, revelando boa aceitação dos participantes, que expressaram seus sentimentos e emoções num setting acolhedor que promoveu a criatividade e a espontaneidade por meio de jogos sonoros, com abertura para novas experiências e socialização, caracterizando-se como medida de promoção da saúde da criança acolhida, com redução de seu estresse.
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Proteomics, the analysis of expressed proteins, has been an important developing area of research for the past two decades [Anderson, NG, Anderson, NL. Twenty years of two-dimensional electrophoresis: past, present and future. Electrophoresis 1996;17:443-53]. Advances in technology have led to a rapid increase in applications to a wide range of samples; from initial experiments using cell lines, more complex tissues and biological fluids are now being assessed to establish changes in protein expression. A primary aim of clinical proteomics is the identification of biomarkers for diagnosis and therapeutic intervention of disease, by comparing the proteomic profiles of control and disease, and differing physiological states. This expansion into clinical samples has not been without difficulties owing to the complexity and dynamic range in plasma and human tissues including tissue biopsies. The most widely used techniques for analysis of clinical samples are surface-enhanced laser desorption/ionisation mass spectrometry (SELDI-MS) and 2-dimensional gel electrophoresis (2-DE) coupled to matrix-assisted laser desorption ionisation [Person, MD, Monks, TJ, Lau, SS. An integrated approach to identifying chemically induced posttranslational modifications using comparative MALDI-MS and targeted HPLC-ESI-MS/MS. Chem. Res. Toxicol. 2003;16:598-608]-mass spectroscopy (MALDI-MS). This review aims to summarise the findings of studies that have used proteomic research methods to analyse samples from clinical studies and to assess the impact that proteomic techniques have had in assessing clinical samples. © 2004 The Canadian Society of Clinical Chemists. All rights reserved.
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The performances of five different ESI sources coupled to a polystyrene-divinylbenzene monolithic column were compared in a series of LC-ESI-MS/MS analyses of Escherichia coli outer membrane proteins. The sources selected for comparison included two different modifications of the standard electrospray source, a commercial low-flow sprayer, a stainless steel nanospray needle and a coated glass Picotip. Respective performances were judged on sensitivity and the number and reproducibility of significant protein identifications obtained through the analysis of multiple identical samples. Data quality varied between that of a ground silica capillary, with 160 total protein identifications, the lowest number of high quality peptide hits obtained (3012), and generally peaks of lower intensity; and a stainless steel nanospray needle, which resulted in increased precursor ion abundance, the highest-quality peptide fragmentation spectra (5414) and greatest number of total protein identifications (259) exhibiting the highest MASCOT scores (average increase in score of 27.5% per identified protein). The data presented show that, despite increased variability in comparative ion intensity, the stainless steel nanospray needle provides the highest overall sensitivity. However, the resulting data were less reproducible in terms of proteins identified in complex mixtures -- arguably due to an increased number of high intensity precursor ion candidates.