279 resultados para Reversibility


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Trabalho final de Mestrado conducente ao grau de Mestre em Engenharia Civil na Área de Especialização de Edificações

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Hydroxychloroquine is an antimalarial drug used in many rheumatologic and systemic diseases. Although considered by clinicians to be relatively safe, serious side effects have been documented (retinotoxicity, neuromyotoxicity and cardiotoxicity). We present the case of a 41-year-old woman with systemic lupus erythematosus (SLE) who presented at our institution with acute heart failure after taking hydroxychloroquine for a period of 3 months. An endomyocardial biopsy ruled out myocarditis related to systemic lupus erythematosus but demonstrated pathological changes related to hydroxychloroquine toxicity. It is exceptional to observe such cardiac toxicity after such a low cumulative dose (16 grams). The potential severity and reversibility of this complication underscores the importance of a high level of suspicion and timely diagnosis.

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Previous studies have shown that polyethylene glycol (PEG)-induced osmotic stress (OS) reduces cell-wall (CW) porosity and limits aluminium (Al) uptake by root tips of common bean (Phaseolus vulgaris L.). A subsequent transcriptomic study suggested that genes related to CW processes are involved in adjustment to OS. In this study, a proteomic and phosphoproteomic approach was applied to identify OS-induced protein regulation to further improve our understanding of how OS affects Al accumulation. Analysis of total soluble proteins in root tips indicated that, in total, 22 proteins were differentially regulated by OS; these proteins were functionally categorized. Seventy-seven per- cent of the total expressed proteins were involved in metabolic pathways, particularly of carbohydrate and amino acid metabolism. An analysis of the apoplastic proteome revealed that OS reduced the level of five proteins and increased that of seven proteins. Investigation of the total soluble phosphoproteome suggested that dehydrin responded to OS with an enhanced phosphorylation state without a change in abundance. A cellular immunolocalization analysis indicated that dehydrin was localized mainly in the CW. This suggests that dehydrin may play a major protective role in the OS-induced physical breakdown of the CW structure and thus maintenance of the reversibility of CW extensibility during recovery from OS. The proteomic and phosphoproteomic analyses provided novel insights into the complex mechanisms of OS-induced reduction of Al accumulation in the root tips of common bean and highlight a key role for modification of CW structure.

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The stability of Ag-TiO(2) photocatalysts was examined for the photocatalytic degradation of dichloroacetic acid (DCA) as a function of the recycling times. The photocatalytic activity was investigated by measuring the rate of H(+) ions released during the photodegradation of DCA and confirmed by measuring the total organic carbon removal. The photodegradation reactions were studied at pH 3 and pH 10 for a series of Ag-TiO(2) photocatalysts as different with Ag loadings. All the Ag-TiO(2) and bare TiO(2) photocatalysts showed a decrease in photocatalytic activity on recycling for the DCA photodegradation reaction. The decrease in activity can be attributed to poisoning of active sites by Cl(-) anions formed during the photocatalytic DCA degradation. The photocatalytic activity was, however, easily recovered by a simple washing technique. The reversibility of the poisoning is taken as evidence to support the idea that the recycling of Ag-P25 TiO(2) photocatalysts does not have a permanent negative effect on their photocatalytic performance for the degradation of DCA. The choice of the preparation procedure for the Ag-TiO2 photocatalysts is shown to be of significant importance for the observed changes in the photocatalytic activity of the Ag-TiO2 particles. Copyright (C) 2008 Victor M. Menendez-Flores et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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A 3D mesoporous TiO2 material with well-developed mesostructure is prepared in the form of a binder-free thin (100 nm) film and studied as potential candidate for the negative electrode in lithium microbatteries. By appropriate thermal treatments, the selected crystal structure (anatase, rutile, or amorphous), and micro-/mesostructure of the materials was obtained. The effects of voltage window and prelithiation treatment improved first cycle reversibility up to 86% and capacity retention of 90% over 100 cycles. After a prolonged intercalation of lithium ions in ordered mesoporous TiO2 appeared small particles assigned to Li2Ti2O4 with cubic structure as observed from ex-situ TEM micrographs. This study highlights the flexibility of the potential window to which the electrode can operate. Maximum capacity values over 100 cycles of 470 μA h cm−2 μm−1 and 177 μA h cm−2 μm−1 are obtained for voltage ranges of 0.1–2.6 V and 1.0–2.6 V, respectively. The observed values are between 6 and 2 times higher than those obtained for films with 600 nm (80 μA h cm−2 μm−1) and 900 nm (92 μA h cm−2 μm−1) lengths. This indicates that 100 nm thin TiO2 films with high accessibility show finite-length type diffusion which is interesting for this particular application.

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En este trabajo de investigación, se diseñó y desarrollo un panel prefabricado para aplicaciones arquitectónicas, compuesto por fibras naturales. El panel fue elaborado a partir de una mezcla de fibras vegetales de tamo de arroz y cabuya, con partículas de arena silícea, los cuales, están aglomerados con una resina de silicato de sodio. La mezcla de estos materiales tiene buenas propiedades de trabajabilidad, compactación y con la aplicación de dióxido de carbono CO2, esta mezcla se solidifica rápidamente. Esta técnica, facilita el proceso de producción en serie de los paneles prefabricados de fibras naturales. A través del moldeo con una prensa manual, se obtuvo paneles con buenas propiedades y características de resistencia, módulo de ruptura, densidad y contenido de humedad; además de tener medidas modulares, texturas de agradable aspecto superficial y criterios de reversibilidad. Los paneles también presentan favorables cualidades de aislamiento térmico y acústico. Sus aplicaciones y utilidades son para revestimiento en espacios interiores de: muros, cielo raso y tabiquería liviana o decorativa. Finalmente se generó una propuesta de instalación de los paneles, utilizando de igual forma recursos renovables y sostenibles.

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Peu satisfaite des concepts généralement mentionnés lorsqu’il s’agit d’écrire sur les films réalisés en stop-motion, je propose d’analyser un corpus de quatre films réalisés par un duo estonien peu connu, les réalisatrices Jelena Girlin et Mari-Liis Bassovskaja, en ancrant mon discours dans une recherche plus large sur l’intimité et la sensorialité en art. J’effleure, par l’entremise d’une revue de littérature, le paradoxe d’animer l’inanimé et l’idée du umheimlich freudien, prégnants dans les écrits substantiels autour du cinéma d’animation en volume. Après avoir démontré que l’œuvre de Girlin Bassovskaja s’incrit dans le domaine de l’intime, j’approfondis l’analyse en m’appuyant sur les théories de la visualité haptique appliquée aux films. Je découvre le corpus à la lumière de ces théories, et évoque l’idée du regard caressant du spectateur vers le film, mais aussi de sa réversibilité. De plus, en tant que réalisatrice-animatrice de court-métrages d’animation, les théories susmentionnées outillent ma pensée afin de décrire ma volonté quasi obsessionnelle de rendre l’intimité tangible par une animation sensuelle en pâte à modeler sur verre.

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Peu satisfaite des concepts généralement mentionnés lorsqu’il s’agit d’écrire sur les films réalisés en stop-motion, je propose d’analyser un corpus de quatre films réalisés par un duo estonien peu connu, les réalisatrices Jelena Girlin et Mari-Liis Bassovskaja, en ancrant mon discours dans une recherche plus large sur l’intimité et la sensorialité en art. J’effleure, par l’entremise d’une revue de littérature, le paradoxe d’animer l’inanimé et l’idée du umheimlich freudien, prégnants dans les écrits substantiels autour du cinéma d’animation en volume. Après avoir démontré que l’œuvre de Girlin Bassovskaja s’incrit dans le domaine de l’intime, j’approfondis l’analyse en m’appuyant sur les théories de la visualité haptique appliquée aux films. Je découvre le corpus à la lumière de ces théories, et évoque l’idée du regard caressant du spectateur vers le film, mais aussi de sa réversibilité. De plus, en tant que réalisatrice-animatrice de court-métrages d’animation, les théories susmentionnées outillent ma pensée afin de décrire ma volonté quasi obsessionnelle de rendre l’intimité tangible par une animation sensuelle en pâte à modeler sur verre.

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In a previous work (Nicu et al. 2013), the flocculation efficiency of three chitosans differing by molecular weight and charge density were evaluated for their potential use as wet end additives in papermaking. According to the promising results obtained, chitosan (single system) and its combination with bentonite (dual system) were evaluated as retention aids, and their efficiency was compared with poly(diallyl dimethyl ammonium chloride) (PDADMAC) and polyethylenimine (PEI). In single systems, chitosan was clearly more efficient in drainage rate than PDADMAC and PEI, especially those with the lowest molecular weights; however, retention is considerably lower. This drawback can be overcome by using dual systems with anionic bentonite microparticles, with the optimum ratio of polymer:bentonite being 1:4 (wt./wt.). In dual systems, the differences in retention were almost negligible, and the difference in drainage rate was even higher, together with better floc reversibility. The most efficient chitosan in single systems was Ch.MMW, while Ch.LMW was the most efficient in dual systems. The flocculation mechanism of chitosan was a combination of patch formation, charge neutralization, and partial bridge formation, and the predominant mechanism depended on the molecular weight and charge density of the chitosan.