884 resultados para Hedberg, Carol


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O câncer de mama representa o tipo de câncer mais comum em mulheres e constitui a primeira causa de morte por câncer nesta população. As alterações extramamárias relacionadas ao câncer de mama desempenham papel relevante no prognóstico e tratamento desta entidade, sendo fundamental a realização do diagnóstico correto e das diversas alterações. A maioria dessas manifestações é proveniente do tratamento adotado ou de suas complicações e pode estar associada a comprometimento linfonodal, recorrência locorregional ou metástases a distância.

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As anomalias congênitas do trato urinário superior implicam modificações morfofuncionais com espectro clínico variável, desde manifestações assintomáticas até falência renal e incompatibilidade com a vida. A tomografia computadorizada, além de ter superado o método de imagem da urografia excretora, tem desempenhado papel fundamental no diagnóstico das anomalias congênitas, orientando melhor nas decisões terapêuticas clínicas e cirúrgicas, além de atuar como ferramenta essencial na identificação de complicações associadas e no melhor desempenho de técnicas operatórias menos invasivas.

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Renal cystic lesions are usually diagnosed in the radiologists' practice and therefore their characterization is crucial to determine the clinical approach to be adopted and prognosis. The Bosniak classification based on computed tomography findings has allowed for standardization and categorization of lesions in increasing order of malignancy (I, II, IIF, III and IV) in a simple and accurate way. The present iconographic essay developed with multidetector computed tomography images of selected cases from the archives of the authors' institution, is aimed at describing imaging findings that can help in the diagnosis of renal cysts.

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The aim of this report is to classify analytical methods based on flowing media and to define (standardize) terminology. After the classification and a discussion of terms describing the systems and component parts, a section is devoted to terms describing the performance of flow systems. The list of terms included is restricted to the most relevant ones; especially "self-explanatory" terms are left out. It is emphasised that the usage of terms or expressions that do not adequately describe the processes or procedures involved should be strongly discouraged. Although belonging to the category of methods based on flowing media, chromatographic methods are not comprised in the present document. However, care has been taken that the present text is not in conflict with definitions in that domain. In documents in which flow methods are described, it should be clearly indicated how the sample and/or reagent is introduced and how the sample zone is transported. When introducing new techniques in the field, or variants of existing techniques, it is strongly recommended that descriptive terms rather than trivial or elaborate names are used.

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When organic compounds present in biological fluids are analysed by chromatographic methods, it is generally necessary to carry out a prior sample preparation due the high complexity of this type of sample, especially when the compounds to be determinated are found in very low concentrations. This article describes some of the principal methods for sample preparation in analyses of substances present in biological fluids. The methods include liquid-liquid extraction, solid phase extraction, supercritical fluid extraction and extraction using solid and liquid membranes. The advantages and disadvantages of these methods are discussed.

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The equilibria, the spectra and the identities of the species of Cr(VI) that are present in aqueous solution have long been an active subject of discussion in the literature. In this paper, three different chemometric methodologies are applied to sets of UV/Visible spectra of aqueous Cr(VI) solutions, in order to solve a chemical system where there is no available information concerning the composition of the samples nor spectral information about the pure species. Imbrie Q-mode factor analysis, followed by varimax rotation and Imbrie oblique projection, were used to estimate the composition of Cr(VI) equilibrium solutions and, by combining these results with the k-matrix method, to obtain the pure spectra of the species. Evolving factor analysis and self modeling curve resolution were used to confirm the number of the species and the resolution of the system, respectively. Sets of 3.3×10-4 and 3.3×10-5 mol L-1 Cr(VI) solutions, respectively, were analyzed in the pH range from 1 to 12. Two factors were identified, which were related to the chromate ion (CrO4(2-)) and bichromate ion (HCrO4-). The pK of the equilibrium was estimated as 5.8.

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Particles of porous silica or other solvent resistent inorganic oxides can be functionalized by aliphatic (e.g., C-8 or C-18) or other groups to give stationary phases for use in reversed phase HPLC. The functionalization can be done by bonding of individual groups to the surface of the support particles, by producing an organic polymeric film from pre-polymers, or by adsorbing/immobilizing pre-formed polymers on the surfaces. These three types of functionalization are reviewed.

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The present work reviews recent advances in the preparation of new reversed phase packing materials such as sterically protected, bidentate, hybrid organic-inorganic and monolithic phases and phases containing embedded polar groups. The bonding chemistry involved in the preparation of these phases as well as their advantages over conventional C8 and C18 reversed phases are discussed. Understanding the reasons behind the development of these newer column packings helps analysts select the best stationary phase for a given application.

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We review the invasive fish species introduced to Catalonia (Spain) and their mechanisms of ecological impact. Catalonia has about 15 established foreign fish species along with many others that have been translocated. These fish species, which are identical to those that have been introduced worldwide (thereby contributing to biotic homogenization), include: common carp (Cyprinus carpio), largemouth bass (Micropterus salmoides), eastern mosquitofish (Gambusia holbrooki) and many European cyprinids that are not native to the Iberian Peninsula. There are some well-documented repercussions to the native fauna, such as the impact of mosquitofish on endangered, endemic cyprinodonts. The illegal introduction by anglers continues to be one of the main culprits of this environmental problem, one that has been barely addressed by local and state authorities

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The validation of an analytical method is fundamental to implementing a quality control system in any analytical laboratory. As the separation techniques, GC, HPLC and CE, are often the principal tools used in such determinations, procedure validation is a necessity. The objective of this review is to describe the main aspects of validation in chromatographic and electrophoretic analysis, showing, in a general way, the similarities and differences between the guidelines established by the different Brazilian and international regulatory agencies.

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Essential aspects for characterization of a flow-based analytical procedure or system are discussed in order to permit the composition of a checklist that will lead to a protocol for reporting results and systems in flow analysis. Aspects more related to chromatographic procedures are not considered. The intent is to present normalized proposals in the field of flow analysis for practitioners and developers.

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This is the first record of the common bream, Abramis brama (Linnaeus, 1758), introduced into the Iberian Peninsula. Eight individuals of this cyprinid fish species were captured (of a total of 978 fish) in the Boadella Reservoir (Catalonia, Spain) on August 18, 2004. This reservoir is only 14 km away from France, where the bream is native, and contains several exotic freshwater fish that are still not widespread in Spain. The further introduction of species and the illegal translocation of the bream by anglers to other Iberian river basins should be controlled by the Spanish administration

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Monolithic stationary phases represent a new generation of chromatographic separation media. These phases consist of a continuous separation bed prepared by in situ polymerization or consolidation inside the column tubing. In recent years, their simple preparation procedure, unique properties and excellent performance have attracted quite remarkable attention in liquid chromatography and capillary electrochromatography. This review summarizes the preparation, characterization and applications of monolithic stationary phases. The analytical potential of these columns is demonstrated with separations involving various families of compounds in different separation modes.