927 resultados para Polyaniline and derivatives


Relevância:

80.00% 80.00%

Publicador:

Resumo:

Este trabalho descreve a síntese, caracterização e aplicação de sistemas poliméricos baseados em polímeros condutores em sistemas de liberação controlada de drogas. Esta tese pode ser dividida em duas partes: na primeira se apresentam os resultados da aplicação de filmes de polianilina e polipirrol na liberação de drogasmodelo como a dopamina protonada e o ácido salicílico. Na liberação de salicilato utilizou-se um filme polianilina eletrosintetizado e dopado com íons cloreto. Já para a liberação de dopamina protonada (um cátion) a liberação foi conduzida a partir de um sistema bicamadas, com um filme de polianilina recoberta com uma camada de Náfion. É mostrada a liberação controlada nos dois casos, porém também se discutem limitaçãoes deste tipo de sistema que levaram ao estudo de uma forma alternativa de controle eletroquímico utilizando polímeros condutores. A segunda parte do trabalho mostra então esta nova metodologia que se baseia em compósitos de poianilina eletropolimerizada no interior de hidrogéis de poliacrilamida. É mostrado que este novo material é eletroativo e mantém as características de intumescimento dos hidrogéis, tanto necessárias ao desenvolvimento destes sistemas de liberação controlada. Mecanismos para o crescimento e distribuição da polianilina na matriz isolante e para a atuação do compósito no controle eletroquímico da liberação são propostos com base nos dados de microscopia de força atômica, Raman e eletrônica de varredura, além de testes de liberação controlada com moléculas de diferentes cargas.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Diversas classes de compostos orgânicos de telúrio foram exploradas neste trabalho. Inicialmente foi estudada a transmetalação entre teluretos alílicos e dibutil cianocupratos de lítio de ordem superior, levando aos respectivos cianocupratos alílicos de lítio. Estes, por sua vez, foram acoplados com triflatos vinílicos, importantes intermediários sintéticos preparados previamente a partir de teluretos vinílicos, levando a sistemas altamente insaturados em ótimos rendimentos (Esquema 1). (Ver no arquivo em PDF) Em seguida, foi explorada a reatividade de teluretos aromáticos frente a reagentes organometálicos. Cianocupratos arílicos, gerados a partir da transmetalação entre teluretos aromáticos com cianocupratos de lítio de ordem superior, foram adicionados a cetonas α,β -insaturadas, levando aos produtos de adição 1,4 em bons rendimentos (Esquema 2). (Ver no arquivo em PDF) Teluretos vinílicos funcionalizados de configuração Z também foram alvo de estudo visando a formação de ligação carbono-carbono. Reações de substituição entre estes teluretos e cianocupratos de lítio de ordem inferior levaram a cetonas e ésteres α,β- insaturados com estereoquímica defInida em ótimos rendimentos (Esquema 3). (Ver no arquivo em PDF) De agosto/20OJ a março/2004, a aluna realizou um estágio sanduíche na University of California, Santa Barbara, sob a orientação do Prof. Bruce H. Lipshutz, onde realizou estudos sobre a ciclização de Bergman, visando a síntese do fragmentobiarílico A-B da vancornicina. Diversas condições para a ciclização foram estudadas com um composto modelo (Esquema 4) (Ver no arquivo em PDF) e parte da síntese total do fragmento da vancomlcma, onde a ciclização seria a etapa-chave, foi realizada com sucesso (Esquema 5). (Ver no arquivo em PDF)

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Objetivo: determinar la calidad de la dieta española mediante el Índice de Alimentación-Saludable (IASE) y su relación con variables geográficas y socioeconómicas. Metodología: Estudio descriptivo transversal a partir de Encuesta-Nacional-Salud-2006 (ENS-2006) Se estudiaron 29.478 personas (Mujeres = 15.019; Hombres = 14.459) que respondieron el Cuestionario de Frecuencia de Consumo (CFC). El IASE se compone de 10 variables (Cereales-derivados, Verduras-hortalizas, Frutas, Leche-derivados, Carnes, Legumbres, Embutidos-fiambres, Dulces, Refrescos-azúcar y Variedad-dieta), construidas a partir del CFC y las recomendaciones de las Guías-Alimentarias (Sociedad-Española-Nutrición-Comunitaria-2004). Categorías IASE (puntuación-máxima 100): Alimentación-saludable: > 80 puntos; Necesita-cambios: > 5.080; Poco-saludable: 50. Se realizó un análisis descriptivo, de diferencias de medias (pruebas Kruskal–Wallis y Mann–Whitney), y prueba Chi-Cuadrado, para estudiar la independencia de las variables edad, sexo, clase-social y nivel de estudios con las categorías de IASE. Resultados: El 72% del total de la muestra necesita cambios en su alimentación. La puntuación media para mujeres es 73,7 ± 10,5 y para hombres 69,9 ± 11,3 (p < 0,001). En la categoría saludable obtienen mayor porcentaje (38,8%) el grupo de edad > 65 años y las mujeres (28,3%) frente a los hombres (18,4%). Así mismo, las clases-sociales más altas (clase-I: 24,4%, clase-II: 25,0%, clase-III: 25,8%) presentan mayor índice de alimentación-saludable, (p < 0,001). Las Comunidades-Autónomas: Comunitat Valenciana (5,4%), Illes Balears (4,6%) y Andalucía (4,3%) son las que presentan mayor índice en la categoría poco-saludable. Conclusiones: El IASE es un método rápido y económico de estimación de la calidad de la dieta de la población, porque utiliza datos secundarios procedente de la ENS y de las guías-alimentarias; siendo útil en la planificación de políticas nutricionales en España.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Objetivo: Determinar el patrón de consumo de alimentos del alumnado de la Universidad de Alicante (UA) mediante el grado de adecuación a la dieta mediterránea. Método: Estudio transversal descriptivo para estimar la ingesta individual a través de un cuestionario de frecuencia de consumo de alimentos (CFCA) en una muestra representativa de 380 universitarios. Variables a estudio: edad, sexo, área geográfica de procedencia, peso y talla autoreferidos. Así como los alimentos y frecuencias de consumo que componen el CFCA. Se determinó el porcentaje de adecuación teniendo en cuenta, consumo real sobre consumo recomendado por la guía dieta mediterránea tradicional: (100 x raciones consumidas/raciones recomendadas). Se establecieron 5 rangos de porcentaje adecuación: consumo óptimo (80%-119%), consumo aceptable (60%-79%), consumo deficiente (40%-59%), consumo muy deficiente (< 39%), consumo excesivo (> 120%). Se realizó contraste de diferencia de proporciones y la prueba t-Student con EPIDAT 3.1, y SPSS 15.0. Resultados: Prevalencia de sobrepeso-obesidad, es mayor en hombres (34,6%) que en mujeres (9,8%), p < 0,001. Mientras que las mujeres presentan mayor prevalencia de bajo peso (7,0%) que hombres (0,7%), p < 0,05. El consumo de cereales y derivados es muy deficiente (mujeres = 90,6; hombres = 94,9), y el consumo de carnes rojas (mujeres = 90,6; hombres = 92,7) y embutidos (mujeres = 95,9%, hombres = 96,3%) es excesivo. Ningún alumno cubre un “consumo óptimo” o un “consumo aceptable” de todos los grupos de alimentos (n = 12). Discusión: El nivel educativo y el acceso a la información no protegen a la población universitaria de factores socioambientales que influencian sus hábitos alimentarios. Deben reforzarse estrategias de salud pública dirigidas a este grupo de población.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Ethanol adsorption on different activated carbons (mostly spherical ones) was investigated covering the relative pressure range from 0.001 to 1. Oxygen surface contents of the ACs were modified by oxidation (in HNO3 solution or air) and/or by thermal treatment in N2. To differentiate the concomitant effects of porosity and oxygen surface chemistry on ethanol adsorption, different sets of samples were used to analyze different relative pressure ranges (below 1000 ppmv concentration and close to unity). To see the effect of oxygen surface chemistry, selected samples having similar porosity but different oxygen contents were studied in the low relative pressure range. At low ethanol concentration (225 ppmv) adsorption is favored in oxidized samples, remarking the effect of the oxidizing treatment used (HNO3 is more effective than air) and the type of oxygen functionalities created (carboxyl and anhydride groups are more effective than phenolic, carbonyl and derivatives). To analyze the high relative pressure range, spherical and additional ACs were used. As the relative pressure of ethanol increases, the effect of oxygen-containing surface groups decreases and microporosity becomes the most important variable affecting the adsorption of ethanol.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The author overviews the use of pregabalin in neuropathic pain. (non-author abstract)

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Mathematics Subject Classification: 26A33, 33C20.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

This survey is devoted to some fractional extensions of the incomplete lumped formulation, the lumped formulation and the formulation of Lauwerier of the temperature field problem in oil strata. The method of integral transforms is used to solve the corresponding boundary value problems for the fractional heat equation. By using Caputo’s differintegration operator and the Laplace transform, new integral forms of the solutions are obtained. In each of the different cases the integrands are expressed in terms of a convolution of two special functions of Wright’s type.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

2000 Mathematics Subject Classification: 26A33, 33C60, 44A20

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Mathematics Subject Classification 2010: 35M10, 35R11, 26A33, 33C05, 33E12, 33C20.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

MSC 2010: 44A20, 33C60, 44A10, 26A33, 33C20, 85A99

Relevância:

80.00% 80.00%

Publicador:

Resumo:

An important problem faced by the oil industry is to distribute multiple oil products through pipelines. Distribution is done in a network composed of refineries (source nodes), storage parks (intermediate nodes), and terminals (demand nodes) interconnected by a set of pipelines transporting oil and derivatives between adjacent areas. Constraints related to storage limits, delivery time, sources availability, sending and receiving limits, among others, must be satisfied. Some researchers deal with this problem under a discrete viewpoint in which the flow in the network is seen as batches sending. Usually, there is no separation device between batches of different products and the losses due to interfaces may be significant. Minimizing delivery time is a typical objective adopted by engineers when scheduling products sending in pipeline networks. However, costs incurred due to losses in interfaces cannot be disregarded. The cost also depends on pumping expenses, which are mostly due to the electricity cost. Since industrial electricity tariff varies over the day, pumping at different time periods have different cost. This work presents an experimental investigation of computational methods designed to deal with the problem of distributing oil derivatives in networks considering three minimization objectives simultaneously: delivery time, losses due to interfaces and electricity cost. The problem is NP-hard and is addressed with hybrid evolutionary algorithms. Hybridizations are mainly focused on Transgenetic Algorithms and classical multi-objective evolutionary algorithm architectures such as MOEA/D, NSGA2 and SPEA2. Three architectures named MOTA/D, NSTA and SPETA are applied to the problem. An experimental study compares the algorithms on thirty test cases. To analyse the results obtained with the algorithms Pareto-compliant quality indicators are used and the significance of the results evaluated with non-parametric statistical tests.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Three closely related human sec14p-like proteins (hTAP1, 2, and 3, or SEC14L2, 3, and 4, respectively) have been described. These proteins may participate in intracellular lipid transport (phospholipids, squalene, tocopherol analogues and derivatives) or influence regulatory lipid-dependent events. Here, we show that the three recombinant hTAP proteins associate with the Golgi apparatus and mitochondria, and enhance the in vitro transport of radioactively labeled α-tocopherol to mitochondria in the same order of magnitude as the human α-tocopherol transfer protein (α-TTP). hTAP1 and hTAP2 are expressed in several cell lines, whereas the expression level of hTAP3 is low. Expression of hTAP1 is induced in human umbilical cord blood-derived mast cells upon differentiation by interleukin 4. In tissues, the three hTAPs are detectable ubiquitously at low level; pronounced and localized expression is found for hTAP2 and hTAP3 in the perinuclear region in cerebellum, lung, liver and adrenal gland. hTAP3 is well expressed in the epithelial duct cells of several glands, in ovary in endothelial cells of small arteries as well as in granulosa and thecal cells, and in testis in Leydig cells. Thus, the three hTAPs may mediate lipid uptake, secretion, presentation, and sub-cellular localization in a tissue-specific manner, possibly using organelle- and enzyme-specific docking sites.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The use of inputs containing phosphites have been presenting results in many studies, taking on importance to the control of diseases in some cultures and demonstrating the resistance induction in seedlings, with ability to activate defense mechanisms, conferring protection to plants against microorganisms. The soybean crop is recognized for its importance in providing grains and derivatives for human consumption, animal, production of biofuels, pharmaceuticals, among others. Positive results obtained through studies based on resistance inducers in some cultures arouse the interest for further study. The objective of this study was to evaluate the effect of potassium phosphites on the resistance induction and treatment of soybean seeds. Therefore were conducted four laboratory studies at the Federal Technological University of Paraná, Campus of Dois Vizinhos. In the first study it was evaluated the quality attributes of the seeds and the resistance induction as seed treatment. Then it was verified that phosphites have action upon the seedlings metabolism in due to seed treatment, having the phosphite Reforce® contributed to seed quality attributes and phosphites FitofosK® and Fitofos K Plus® induced the resistance increasing the activity of β-1,3-glucanase. In the second study it was evaluated the the resistance induction in soybean cotyledons, in which the phosphites demonstrated induction potential of phytoalexin gliceolin. In the third study It was evaluated the soybean seed health treated with potassium phosphites.. it was observed that the phosphites reduced the incidence of many fungi on seeds, especially of storage fungi like Aspergillus sp. and Fusarium semitectum. In the fourth study it was evaluated the in vitro effect of potassium phosphites on pathogenic fungi of the culture. And it was found direct action of phosphites on the mycelial growth of Fusarium semitectum, Pythium sp. and Sclerotinia sclerotiorum. Based on these results, we concluded that potassium phosphites have potential in seeds treatment, as resistance inducer and on in vitro control of phytopathogens.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Mestrado em Contabilidade e Análise Financeira