Doenças do metabolismo do colesterol: cromatografia de esteróis no diagnóstico de 25 casos em Portugal

Os esteróis desempenham um papel fundamental nos processos fisiológicos de praticamente todos os organismos vivos. O esterol mais abundante nos seres humanos é o colesterol, o qual desempenha uma multiplicidade de funções desde a estrutural à sinalização. A extração e análise de esteróis no plasma é complexa devido à sua insolubilidade, sequestração dentro das lipoproteínas e à grande diferença entre cada tipo de esterol. Os autores apresentam a casuística referentes à análise de 13 esteróis e fitosteróis em plasma e líquido amniótico.

Las variaciones en colesterol-HDL tras bypass gástrico proximal son independientes de la evolución ponderal

Fundamento. La cirugía bariátrica posee efectos beneficiosos sobre el perfil lipídico en pacientes con obesidad mórbida que pueden atenuarse con la recuperación ponderal. El presente estudio se ha llevado a cabo para evaluar el perfil lipídico antes y a lo largo de los seis años consiguientes a la realización de bypass gástrico proximal (BPG). Material y métodos. Se han estudiado 177 pacientes (135 mujeres) con obesidad mórbida (IMC 44,2+0,4 kg/m²) de 42,4+0,9 años de edad antes, 3,6,9, 12,24,36,48,60 y 72 meses después de realizar BPG. En todas las revisiones se evaluó el tratamiento hipolipemiante, antropometría (IMC, cintura), composición corporal (Bod-Pod) y determinaciones de colesterol total (CT), colesterol-LDL (LDL-C), colesterol-HDL (HDL-C), triglicéridos (TG), glucosa e insulina. Resultados. El BPG indujo marcada reducción de IMC (nadir IMC a 18 meses 28,3+0,4 kg/m² p<0,001) y grasa corporal consiguiendo una pérdida de exceso IMC del 84,1% y del exceso de porcentaje de grasa del 87% que disminuyó al 65,6 y 38,3% (ambos p<0,005 respecto a nadir) respectivamente a los 6 años del BPG, indicando recuperación de peso y grasa corporal. Los valores de TG alcanzaron el 70% a los 60 meses, los de LDL-C el 70,6% a los 18 meses y los de HDL-C el 197% del valor pre-intervención a los 48 meses. La elevación de HDL-C aumentó durante la fase de recuperación ponderal de forma continuada (p<0,001). Tanto los cocientes CT/HDL-C como TG/HDL-C se normalizaron de forma mantenida durante los 6 años de seguimiento. Conclusiones. Estos resultados confirman la mejoría de todas las fracciones lipídicas 6 años después del BPG, con especial mención a HDL-C, que mantuvo progresión creciente incluso durante la recuperación ponderal, reduciendo la tasa de dislipemia a los 6 años del BPG.

Obtenção de óxidos a base de níquel e cobalto para reação de oxidação parcial do metano

Nickel-based catalysts supported on alumina have been widely used in various reactions to obtain synthesis gas or hydrogen. Usually, higher conversion levels are obtained by these catalysts, however, the deactivation by coke formation and sintering of metal particles are still problems to be solved. Several approaches have been employed in order to minimize these problems, among which stands out in recent years the use of additives such as oxides of alkali metals and rare earths. Similarly, the use of methodologies for the synthesis faster, easier, applicable on an industrial scale and to allow control of the microstructural characteristics of these catalysts, can together provide the solution to this problem. In this work, oxides with spinel type structure AB2O4, where A represents divalent cation and B represents trivalent cations are an important class of ceramic materials investigated worldwide in different fields of applications. The nickel cobaltite (NiCo2O4) was oxides of spinel type which has attracted considerable interest due to its applicability in several areas, such as chemical sensors, flat panel displays, optical limiters, electrode materials, pigments, electrocatalysis, electronic ceramics, among others. The catalyst precursor NiCo2O4 was prepared by a new chemical synthesis route using gelatine as directing agent. The polymer resin obtained was calcined at 350°C. The samples were calcined at different temperatures (550, 750 and 950°C) and characterized by X ray diffraction, measurements of specific surface area, temperature programmed reduction and scanning electron microscopy. The materials heat treated at 550 and 750°C were tested in the partial oxidation of methane. The set of techniques revealed, for solid preparations, the presence of the phase of spinel-type structure with the NiCo2O4 NixCo1-xO solid solution. This solid solution was identified by Rietveld refinement at all temperatures of heat treatment. The catalyst precursors calcined at 550 and 750°C showed conversion levels around 25 and 75%, respectively. The reason H2/CO was around 2 to the precursor treated at 750°C, proposed reason for the reaction of partial oxidation of methane, one can conclude that this material can be shown to produce synthesis gas suitable for use in the synthesis Fischer-Tropsch process

Síntese e caracterização de óxidos de cério e cobalto obtidos por gel-combustão e Pechini aplicados às reações de oxidação de n-hexano

Oxide type spinel AB2O4 presents structure adjusted for application in the automobile industry. The spinel of cobalt has many practical applications had its excellent physical and chemical properties such as catalyst in hydrocarbon oxidation reaction. The CeO2 has been used in many of these processes because it assigns to a material with excellent thermal resistance and mechanics, high capacity of oxygen stockage (OSC) among others properties. This work deals with the synthesis, characterization and catalytic application of spinel of cobalt and CeO2 with fluorita structure, obtained for method of Pechini and method of Gel-Combustion. The process of Pechini, the puff was obtained at 300 ºC for 2 h in air. In the process of Gel-Combustion the approximately at 350 ºC material was prepared and burnt for Pyrolysis, both had been calcined at 500 ºC, 700 ºC, 900 ºC and 1050 ºC for 2 h in air. The materials of the calcinations had been characterized by TG/DTA, electronic microscopy of sweepings (MEV), spectroscopy of absorption in the infra-red ray (FTIR) and diffraction of X-rays (DRX). The obtained material reaches the phase oxide at 450 oC for Pechini method and 500 °C for combustion method. The samples were submitted catalytic reaction of n-hexane on superficies of materials. The reactor function in molar ration of 0, 85 mol.h-1.g-1 and temperature of system was 450 °C. The sample obtained for Pechini and support in alumine of superficial area of 178,63 m2.g-1 calcined at 700 ºC, give results of catalytic conversions of 39 % and the sample obtained for method of gel-combustion and support in alumina of 150 mesh calcined at 500 ºC result 13 % of conversion. Both method were selective specie C1

Degradação do PMMA através da reação despolimerização uitlizando catalisadores de óxidos mistos

In this work, mixed oxides were synthesized by two methods: polymeric precursor and gel-combustion. The oxides, Niquelate of Lanthanum, Cobaltate of Lanthanum and Cuprate of Lanthanum were synthesized by the polymeric precursor method, and treated at 300 º C for 2 hours, calcined at 800 º C for 6h in air atmosphere. In gel-combustion method were produced and oxides using urea and citric acid as fuel, forming for each fuel the following oxides Ferrate of Lanthanum, Cobaltato of Lanthanum and Ferrato of Cobalt and Lanthanum, which were submitted to the combustion process assisted by microwave power maximum of 10min. The samples were characterized by: thermogravimetric analysis, X-ray diffraction; fisisorção of N2 (BET method) and scanning electron microscopy. The reactions catalytic of depolymerization of poly (methyl methacrylate), were performed in a reactor of silica, with catalytic and heating system equipped with a data acquisition system and the gas chromatograph. For the catalysts synthesized using the polymeric precursor method, the cuprate of lanthanum was best for the depolymerization of the recycled polymer, obtaining 100% conversion in less time 554 (min), and the pure polymer, was the Niquelate of Lanthanum, with 100% conversion in less time 314 (min). By gel-combustion method using urea as fuel which was the best result obtained Ferrate of Lanthanum for the pure polymer with 100% conversion in less time 657 (min), and the recycled polymer was Cobaltate of Lanthanum with 100 % conversion in less time 779 (min). And using citric acid to obtain the best result for the pure polymer, was Ferrate of Lanthanum with 100% conversion in less time 821 (min and) for the recycled polymer, was Ferrate of Lanthanum with 98.28% conversion in less time 635 (min)

Preparação de óxidos mistos de níquel e zinco nanoparticulados a partir de combustíveis alternativos

The field of "Materials Chemistry" has been developing in recent years and there has been a great increase of interest in the synthesis and chemical and physical properties of new inorganic solids. New routes of synthesis and synthesis modified has been developed with the aim not only to optimize the processes in laboratory scale, but also on an industrial scale, and make them acceptable by current environmental legislation. The phenomenology of current solid state chemistry properties coupled with the high temperature superconductivity, ferromagnetism, porosity molecular and colors are evidence affected by the synthesis method, which in turn can influence the technological application of these materials. From this understanding, mixed oxides of nickel and zinc nanoparticulate were synthesized by microwave-assisted combustion route using three specific types of organic fuels employing the weight ratios 1:1/2 and 1:1 of cation metallic/fuel, in order to investigate the influence of such proportions to obtain the solids. The new fuels were chosen to replace, for example, urea or glycine that are the fuels most commonly preferred in this kind of synthesis. The powders without heat treatment were studied by Thermogravimetric analysis (TGA), X-Ray Diffraction (XRD) and then calcined at 900°C. After heat treatment, the samples were characterized by analysis of X Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The modified synthesis route porposed was effective for obtaining powders. Both the alternative fuels chosen as the different weight ratios employed, influenced in the morphology and obtaining oxides

Fabricación y caracterización de películas delgadas de óxidos transparentes con aplicaciones ópticas.

Los óxidos transparentes conductores (TCO′ s) son materiales compuestos conformados por oxígeno y un metal, que presentan una combinación única de alta estabilidad química, alta concentración electrónica y alta transparencia óptica. Por esta razón, el procesamiento de TCO′ s en película delgada va orientado hacia aplicaciones específicas tales como ventanas ópticas en celdas solares, sensores de gases, electrodos en dispositivos de pantallas planas, ventanas inteligentes. En este proyecto se trabajó en la síntesis experimental de dos TCO′ s relevantes tanto en investigación fundamental como en aplicaciones tecnológicas: el óxido de indio (In2O3) y el óxido de estaño (SnO2). Ambos TCO′ s se depositaron por la técnica de erosión iónica reactiva por corriente directa (DC). Para el análisis de las películas se utilizaron varias técnicas de caracterización: difracción de rayos X, espectroscopia UV-Visible, resistividad eléctrica, efecto Hall, así como microscopías electrónica de barrido y de fuerza atómica. Se fabricó también una bicapa de In2O3/SnO2, la cual se caracterizó además con espectroscopia de fotoemisión de rayos X (XPS).En esta tesis se reporta por primera vez la síntesis y caracterización de esta bicapa, la cual abre una línea de investigación en el área de interfaces. Asimismo, se desarrolló e implementó un procedimiento, basado en los modelos ópticos, tal que permite obtener parámetros que se utilizan para evaluar a cualquier película delgada TCO como potencial metamaterial. Las propiedades de las muestras se analizaron en función de la temperatura aplicada post-depósito: temperatura ambiente (TA), 100oC, 200oC, 300oC, bajo una atmósfera de argón o argón-oxígeno. Los resultados confirman que las películas presentan un crecimiento de tipo poli cristalino. Además, la calidad cristalina tiende a incrementarse como función del incremento de la temperatura. El In2O3 creció con estructura cúbica bcc (a=10.11 ˚A, ICDD #71-2195). A partir de 200C, se detectaron trazas de la fase romboédrica (a=5.490 ˚A, c=14.520 ˚A, ICDD #73-1809). Asimismo, el SnO2 creció con estructura tetragonal (a = 4.737 ˚A, c = 3.186 ˚A, ICDD #88-0287). Las películas de In2O3 poseen una transparencia promedio del 90 % en una ventana de 500 nm a 1100 nm. El borde de absorción se recorre al azul como función de la temperatura, de Eg=3.3 eV a Eg=3.7 eV por el efecto Burstein-Moss. Por otra parte, la bicapa presentó una interfaz claramente definida, sin difusión de especies metálicas. Al incrementarse la temperatura, de TA a 400oC, se detectaron dos fases de óxido de estaño: SnO2 y SnO, en un porcentaje atómico de ≈70 %:30 %, respectivamente. Se concluye que los parámetros y valores obtenidos de las películas como son el texturizado y espesor homogéneo, alta transparencia, crecimiento preferencial, ancho prohibido y resistividad eléctrica, son comparables a los que se requieren del In2O3 y SnO2 en película delgada para aplicaciones optoelectrónicas.

Influencia de la inserción de nano-óxidos cerámicos sobre la microestructura y propiedades de una porcelana triaxial.

La nanociencia y nanotecnología han revolucionado las investigaciones en ciencia de los materiales, permitiendo el desarrollo de nuevos productos con desempeño superior a los convencionales. Conceptos nanotecnológicos como la adición de partículas en tamaños nanométricos para incrementar las propiedades finales han sido demostrados en cerámicos, sin embargo esta alternativa prácticamente no ha sido investigada en sistemas porcelánicos, específicamente en porcelanas triaxiales con aplicaciones eléctricas. Este trabajo de investigación presenta el desarrollo de una formulación de porcelana triaxial silicosa, de grado eléctrico, con características mecánicas y dieléctricas mejoradas mediante la incorporación de nanopartículas cerámicas. Se estudió la influencia de la adición de dos tipos de óxidos cerámicos en tamaño nanométrico, α- alúmina (α-Al2O3) y circonia (ZrO2), en las propiedades y microestructura de la porcelana triaxial, al variar la concentración de las nanopartículas en la composición inicial. En la primera parte de la experimentación, se elaboraron probetas experimentales siguiendo un proceso a nivel laboratorio haciendo uso de un conformado por presión uniaxial. Posteriormente, se elaboraron pastas porcelánicas a nivel planta-prototipo mediante un proceso de conformado por extrusión plástica. Las probetas sinterizadas fueron caracterizadas mediante evaluaciones físicas tales como densidad, porosidad, absorción de humedad y contracción lineal; así mismo se llevaron a cabo análisis microestructurales y de fases a través de las técnicas de DR-X, MEB y DSC-TGA. Por último, se realizaron evaluaciones mecánicas por medio de ensayos de resistencia a la compresión y módulo de ruptura (por tres puntos), así como la evaluación de la capacidad aislante con pruebas de resistencia dieléctrica. Los resultados obtenidos demuestran que la inserción de nanopartículas de alúmina y circonia, ayudan en el reforzamiento mecánico del sistema porcelánico triaxial estudiado, además de mejorar sus características dieléctricas, lo que representa una alternativa tecnológicamente factible para mejorar el desempeño de productos de porcelana, como es el caso de aisladores eléctricos

Pirólise rápida catalítica do capim elefante utilizando materiais mesoporosos e óxidos metálicos para deoxigenação em bio-óleo

The fast pyrolysis of lignocellulosic biomass is a thermochemical conversion process for production energy which have been very atratactive due to energetic use of its products: gas (CO, CO2, H2, CH4, etc.), liquid (bio-oil) and charcoal. The bio-oil is the main product of fast pyrolysis, and its final composition and characteristics is intrinsically related to quality of biomass (ash disposal, moisture, content of cellulose, hemicellulose and lignin) and efficiency removal of oxygen compounds that cause undesirable features such as increased viscosity, instability, corrosiveness and low calorific value. The oxygenates are originated in the conventional process of biomass pyrolysis, where the use of solid catalysts allows minimization of these products by improving the bio-oil quality. The present study aims to evaluate the products of catalytic pyrolysis of elephant grass (Pennisetum purpureum Schum) using solid catalysts as tungsten oxides, supported or not in mesoporous materials like MCM-41, derived silica from rice husk ash, aimed to reduce oxygenates produced in pyrolysis. The biomasss treatment by washing with heated water (CEL) or washing with acid solution (CELix) and application of tungsten catalysts on vapors from the pyrolysis process was designed to improve the pyrolysis products quality. Conventional and catalytic pyrolysis of biomass was performed in a micro-pyrolyzer, Py-5200, coupled to GC/MS. The synthesized catalysts were characterized by X ray diffraction, infrared spectroscopy, X ray fluorescence, temperature programmed reduction and thermogravimetric analysis. Kinetic studies applying the Flynn and Wall model were performed in order to evaluate the apparent activation energy of holoceluloce thermal decomposition on samples elephant grass (CE, CEL and CELix). The results show the effectiveness of the treatment process, reducing the ash content, and were also observed decrease in the apparent activation energy of these samples. The catalytic pyrolysis process converted most of the oxygenate componds in aromatics such as benzene, toluene, ethylbenzene, etc

Filmes formados pelo copolímero SEBS e nanopartículas de óxidos de ferro : preparação e caracterização

Dissertação (mestrado)—Universidade de Brasília, Instituto de Física, Programa de Pós-Graduação em Física, 2016.

Segunda Opinião Formativa: Pacientes com níveis elevados de colesterol e triglicerídeos devem ser tratados com fibrato associado a estatinas ou usar apenas o fibrato? Depois de quanto tempo de tratamento repetir os exames para acompanhamento?

Resposta sistematizada, com base em revisão bibliográfica, nas melhores evidências científicas e clínicas e no papel ordenador da Atenção Básica à Saúde, para pergunta sobre uso de fibrato em pacientes com níveis elevados de colesterol e triglicerídeos. Informa sobre tratamento da hipertrigliceridemia e tratamento da hipercolesterolemia.

Controle do nível de colesterol relacionado aos hábitos e costumes culturais de comunidades rurais do município de Curvelo, Minas Gerais

Ao examinar resultados laboratoriais solicitados em consultas de rotina da população da zona rural do município de Curvelo, Minas Gerais, junto a Unidade de Saúde que atuo como médica da Estratégia Saúde da Família, foram observados alterados os níveis de colesterol, fazendo-se necessário iniciar o tratamento medicamentoso com a finalidade de realizar esse controle e elaborar estratégias para orientar esses pacientes sobre a importância da atividade física e a reeducação alimentar. No atendimento prestado a esses pacientes, em especial, durante a anamnese, buscou-se compreender o porquê de tantos pacientes apresentarem o nível de colesterol alterado, e observou-se que muitos dentre esses cultivavam hábitos de vida e costumes culturais que favoreciam essa alteração nos níveis de colesterol. Assim, o objetivo do presente trabalho foi promover ações direcionadas ao controle do nível de colesterol junto aos pacientes que apresentavam tais alterações e residiam nas comunidades da zona rural de Curvelo