Biblioteca Digital

O presente trabalho se destina a um estudo detalhado da chamada equação de spin, a qual pode ser utilizada para descrever o comportamento de sistemas de dois níveis. Para campos externos dados por funções reais, esta equação pode ser identificada com uma redução da equação de Pauli para o caso 0+1 dimensional. Inicialmente, demonstraremos a relação entre esta equação de spin e várias outras equações relacionadas com diversos problemas em física. Com estas relações, podemos construir novas soluções da equação de spin a partir do conhecimento de soluções exatas destes outros problemas e, por outro lado, estender a aplicação das soluções obtidas. Em seguida, descrevemos a forma geral da solução desta equação, construímos o operador de evolução e resolvemos o problema inverso, i.e., a determinação do campo externo supondo o conhecimento de uma solução. Finalizando, para o importante caso de campos externos reais, desenvolvemos um método de construção de novas soluções a partir de uma solução previamente conhecida, utilizando a chamada transformação de Darboux. Em particular, demonstramos a existência de operadores de entrelaçamento de Darboux, que não violam a estrutura específica dos sistemas de dois níveis...

A avaliação da estabilidade dos medicamentos e sua correta utilização em diferentes veículos de infusão são fundamentais para garantir a manutenção das características terapêuticas do fármaco e para promover minimização de eventos adversos. Incompatibilidades entre as estruturas dos fármacos, em diferentes veículos de administração, podem gerar possíveis associações antagônicas ou sinérgicas, resultando em alterações das propriedades físico-químicas e, consequentemente, dos efeitos farmacológicos e das respostas clínicas esperadas. A proteína verde fluorescente (GFP) por apresentar propriedades de sensibilidade e especificidade, mostra-se promissora como potencial biossensor da estabilidade de fármacos em soluções parenterais de grande volume (SPGV), por apresentar sensibilidade a alterações das propriedades físico-químicas do meio. GFP é uma proteína compacta, globular e ácida, composta de um monômero de 27kDa, que vem sendo extensivamente utilizada como indicador biológico em processos de esterilização e desinfecção devido a sua estabilidade a altas temperaturas. O surgimento de métodos analíticos modernos e de alta precisão como a espectrofotometria de UV e a cromatografia líquida de alta eficiência (HPLC)...

Diante da extensa utilização de fármacos associados às soluções parenterais de grande volume (SPGV) e muitas vezes da impossibilidade da administração dos mesmos em diferentes veículos de infusão, sejam pela perda da estabilidade ou por insolubilidade destes, a utilização de copolímeros como carreadores de fármacos vêm a favorecer a associação destes às SPGV. Este trabalho visa avaliar a estabilidade dos fármacos ceftazidima e aminofilina nas SPGV carreados pelo copolímero Pluronic® F68 e o estudo da GFP como potencial biossensor da estabilidade de fármacos nas SPGV. A estabilidade dos fármacos ceftazidima (320ug/mL) e aminofilina (160ug/mL) em SPGV foi avaliada, na presença e na ausência de Pluronic® F68, através da utilização de HPLC logo após preparo e após período de 24hs, usando sistema Schimadzu LC10, LC-solution software, Schimadzu C18, fluxo 0,5mL/min, detecção em λ=255nm (ceftazidima) e λ=275nm (aminofilina), volume de injeção 20uL, 25ºC. A determinação da concentração mínima inibitória (CMI) foi realizada em amostras de ceftazidima (240ug/mL) na presença e na ausência de Pluronic® em SPGV de 5% glicose usando E. coli ATCC 25922 e P.eruginosa ATCC 9721 na concentração de 106UFC/mL . Pluronic® F68 foi utilizado nas amostras para avaliação da estabilidade dos fármacos ceftazidima e aminofilina na concentração 10% m/m. Resultados mostraram uma incompatibilidade entre a associação dos fármacos em SPGV de 5% glicose...

O estudo de soluções proteicas visando à modelagem e à simulação de processos de recuperação e purificação de bioprodutos passa necessariamente pelo estudo da não idealidade, em sentido termodinâmico, destas soluções. Para sistemas em que a concentração de proteína seja baixa, situação comumente presente nestes processos, a principal maneira de avaliar experimentalmente a não idealidade é por meio da determinação da pressão osmótica gerada pela proteína. Deste modo, os objetivos deste trabalho foram: estudar a influência de co-solventes na pressão osmótica de soluções proteicas, verificar a integridade das estruturas secundária e terciária das proteínas nessas soluções, e modelar termodinamicamente os dados de pressão osmótica obtidos. A pressão osmótica foi determinada diretamente por osmometria de membrana, usando soluções de referência com mesma concentração de co-solvente e pH, mas isentas de proteínas. Obtiveram-se dados de pressão osmótica, em função da concentração proteica, de cinco diferentes proteínas (albumina de soro bovino, imunoglobulina G humana, ovalbumina, -lactoglobulina e lisozima) em soluções contendo co-solventes como o polietileno glicol (de diversos tamanhos de cadeia) e sais (sulfato de amônio...

INTRODUÇÃO: A lesão de isquemia-reperfusão continua sendo considerada a maior causa de mortalidade relacionada ao transplante de pulmão e sua gravidade é influenciada por diversos fatores, dentre eles, a preservação pulmonar. OBJETIVO: Comparar duas soluções de preservação pulmonar, Perfadex® e Celsior®, quanto a capacidade de preservação de tecido pulmonar isquêmico. MÉTODOS: Sessenta pulmões de ratos preservados com Perfadex®, Celsior® ou solução salina após períodos de isquemia hipotérmica de 6 ou 12 horas, foram reperfundidos com sangue homólogo em modelo experimental ex-vivo durante 60 minutos consecutivos. A cada 10 minutos os dados de gasometria, hematócrito, mecânica ventilatória, hemodinâmica e peso do bloco cardiopulmonar foram registrados. Ao final da reperfusão o pulmão esquerdo foi pesado e acondicionado por 48h a 70oC para obtenção da razão peso úmido/peso seco, bem como amostras de tecido pulmonar foram retiradas para histopatologia, microscopia eletrônica e TUNEL. A análise estatística incluiu a comparação entre as soluções e os tempos de isquemia, utilizando ANOVA e Kruskall-Wallis. O nível de significância foi de 5%. RESULTADOS: A comparação entre as complacências de pulmões preservados com Celsior® e Perfadex® nos tempos de isquemia de 6 e 12 horas não apresentou significância estatística (p=0...

Voriconazole is a novel broad-spectrum antifungal drug, employed in the treatment of invasive fungal infections, and represents an alternative to amphotericin B treatment. The manufacturer recommends that any unused reconstituted product should be stored at 2ºC to 8ºC, for no more than 24 h, but no recommendations about i.v. infusion solutions are given. Previous works have reported on the stability of voriconazole in polyolefin bags and just one in 5% dextrose polyvinyl chloride (PVC) bags, at a 4 mg.mL-1 concentration. In this work, the stability of voriconazole as an i.v. infusion solution in 0.9% sodium chloride and in 5% dextrose, in PVC bags, at 0.5 mg.mL-1, stored at 4 ºC and at room temperature, protected from light, was evaluated. These infusion solutions were analyzed for a 21-day period. Chemical stability was evaluated by HPLC assay. Visual inspection was performed and pH of the solutions was measured. No color change or precipitation in the solutions was observed. The drug content remained above 90% for 11 days in 0.9% sodium chloride and for 9 days in 5% dextrose solutions. The i.v. infusion solutions stored at room temperature were not stable. At room temperature, the voriconazole content dropped down to 88.3 and 86.6%...

The increasing concerns about climate change and global warming has increase the interest in reducing the emissions of greenhouse gases (GHG), mainly CO2. Thus, the chemical absorption of carbon dioxide by aqueous amine solutions has been investigated over the last decades. The studies were performed in two distinct stages. The first one was the preliminary trials. In these trials, the absorption of carbon dioxide and the solvent regeneration/release of carbon dioxide were performed. The second one consisted on the performance of carbon dioxide absorption in a pilot unit, with the aqueous amine solutions that showed the best results in the preliminary trials and the amine solutions that were to be tested in the previous work. In the carbon dioxide absorption tests performed in the preliminary trials,the goal was to study the energy efficiency of each tested amine solution, i.e., at which temperature the solutions would start releasing the absorbed CO2. The following aqueous amine solutions with a concentration of 20 % by weight wer etested: isopropylamine, diisopropylamine, diethylamine, bis(2 -ethylhexyl)amine, dimethylethanolamine (DMEA) and triethylamine. The isopropylamine aqueous solutions was not prepared...

Voriconazole is a novel broad-spectrum antifungal drug, employed in the treatment of invasive fungal infections, and represents an alternative to amphotericin B treatment. The manufacturer recommends that any unused reconstituted product should be stored at 2ºC to 8ºC, for no more than 24 h, but no recommendations about i.v. infusion solutions are given. Previous works have reported on the stability of voriconazole in polyolefin bags and just one in 5% dextrose polyvinyl chloride (PVC) bags, at a 4 mg.mL-1 concentration. In this work, the stability of voriconazole as an i.v. infusion solution in 0.9% sodium chloride and in 5% dextrose, in PVC bags, at 0.5 mg.mL-1, stored at 4 ºC and at room temperature, protected from light, was evaluated. These infusion solutions were analyzed for a 21-day period. Chemical stability was evaluated by HPLC assay. Visual inspection was performed and pH of the solutions was measured. No color change or precipitation in the solutions was observed. The drug content remained above 90% for 11 days in 0.9% sodium chloride and for 9 days in 5% dextrose solutions. The i.v. infusion solutions stored at room temperature were not stable. At room temperature, the voriconazole content dropped down to 88.3 and 86.6%...

Este trabalho apresenta métodos de cálculo aproximado do campo de uma onda se propagando na ionosfera. A ionosfera é um dos meios mais complexos quando se deseja calcular a intensidade de campo de uma onda eletromagnética, porque ela possui uma densidade eletrônica que varia com as estações do ano, e principalmente com a hora do dia. Outra dificuldade para soluções das equações diferenciais na ionosfera é sua característica de material anisotrópico que produz dois modos de propaga»c~ao na mesma, provenientes dos dois índices de refração que a mesma apresenta. Esta anisotropia é proveniente da existência do campo magnético terrestre. Este trabalho teve como principal objetivo o cálculo do campo de uma onda na ionosfera, mas inicialmente considerou-se um meio sem campo magnético, apenas com influência da densidade eletrônica. Quando despreza-se o campo magnético terrestre, que não é o caso real, a ionosfera se comporta como meio isotrópico e a solução das equações diferenciais que governam os campos pode ser dada por funções conhecidas como: funções de Airy quando se considera o modelo de densidade linear, funções de Bessel quando se considera o modelo exponencial, e funções de Weber quando o modelo de densidade é parabólico. Quando a densidade eletrônica n~ao segue nenhuma função conhecida para representar uma ionosfera real...

Les objets d’étude de cette thèse sont les systèmes d’équations quasilinéaires du premier ordre. Dans une première partie, on fait une analyse du point de vue du groupe de Lie classique des symétries ponctuelles d’un modèle de la plasticité idéale. Les écoulements planaires dans les cas stationnaire et non-stationnaire sont étudiés. Deux nouveaux champs de vecteurs ont été obtenus, complétant ainsi l’algèbre de Lie du cas stationnaire dont les sous-algèbres sont classifiées en classes de conjugaison sous l’action du groupe. Dans le cas non-stationnaire, une classification des algèbres de Lie admissibles selon la force choisie est effectuée. Pour chaque type de force, les champs de vecteurs sont présentés. L’algèbre ayant la dimension la plus élevée possible a été obtenues en considérant les forces monogéniques et elle a été classifiée en classes de conjugaison. La méthode de réduction par symétrie est appliquée pour obtenir des solutions explicites et implicites de plusieurs types parmi lesquelles certaines s’expriment en termes d’une ou deux fonctions arbitraires d’une variable et d’autres en termes de fonctions elliptiques de Jacobi. Plusieurs solutions sont interprétées physiquement pour en déduire la forme de filières d’extrusion réalisables. Dans la seconde partie...

peer-reviewed; Dimensional restrictions in electronic equipment have resulted in miniaturisation of many existing cooling technologies. In addition, cooling solutions are required to dissipate increased thermal loads to maintain component reliability and user comfort. Fans are widely used in electronics cooling to meet such thermal demands, either in standalone for direct component cooling, or in combination with a heat sink. The thermal performance of such designs when scaled to dimensions suitable for use in portable electronics has received limited attention, mainly due to the reliance on passive cooling methodologies currently employed. However, as heat flux increases, passive cooling is reaching its limit and other solutions will be required. This thesis aims to address this issue by experimentally examining the fluid dynamics and thermal performance of forced convection cooling solutions with dimensional constraints. Conventional finned and novel finless heat sink designs have been integrated with commercially available radial blowers to investigate cooling solutions with overall foot print areas as low as 487mm2, and profile heights less than 5mm. The novel finless geometry, with reduced manufacturing cost, energy consumption and weight promoted heat transfer above that of the same size classical finned designs for a range of operating points. Both geometries showed increases of up to 20% in thermal performance by aligning the fan exit flow with the heat sink channels...

Chelator-buffered hydroponic solutions provide low and buffered free-metal concentrations and allow the easy calculation of nutrient species expected in these solutions. Some researchers suspect that the solutions allow plant uptake of chelates and that this uptake explains the failure of the free-ion activity model using these solutions. To determine the amount and method of chelate uptake, swiss chard was grown in solution culture in growth chambers for about three wks and then transferred to solutions containing 14C-EDTA, 14C-citrate, or 14C-L-histidine for a 21-hour assay. Much higher root and shoot 14C were found from treatments containing metabolites histidine (2706097 shoot Bq 14C) or citrate (2241953 shoot Bq 14C) than EDTA (280110 shoot Bq 14C). Passive transpirational flow could explain all of the EDTA uptake, but active uptake would be required to explain most of the citrate and histidine uptake even assuming some adsorption of ligand bound to roots. Swiss chard grown in solutions with the same total EDTA concentrations, but different amounts of Fe bound to EDTA, had 3-fold differences in root and shoot 14C concentrations. In a second experiment, swiss chard roots removed more EDTA from solutions containing mostly M-EDTA0 than M-EDTA1- or M-EDTA2- (288140...

BACKGROUND: Lysozyme is an innate immune peptide with bactericidal and fungicidal activity (FA). Despite increased expression of lysozyme protein in chronic rhinosinusitis (CRS) sinus mucosa, CRS patients experience repeated bacterial and/or fungal infections. Commercial sinus irrigation solutions are often used to provide symptomatic relief. However, one of the mechanisms of action of lysozyme involves ionic interactions with the microbial cell wall, which may be inhibited by ionic solutions such as commercial sinus irrigation solutions. OBJECTIVE: Determine if the FA of lysozyme is reduced in the presence of solutions with increasing ionic strength and inhibited in the presence of commercial sinus irrigation solutions. METHODS: Using an in vitro colony-forming unit (CFU) assay, the FA of lysozyme (5 μM) was tested against a fungi commonly isolated from CRS patients, Aspergillus fumigatus, in solutions of increasing ionic strength or commercial sinus irrigation solutions. FA was presented as percent of control. RESULTS: FA of lysozyme against A. fumigatus was 95% in a 21-mM ionic strength solution. However, with increasing ionic strength, FA decreased and was abolished in a 46-mM ionic strength solution. Commercial sinus irrigation solutions abolished the FA of lysozyme against A. fumigatus. CONCLUSION: The in vitro FA of lysozyme is dependent on the ionic strength of the solution. The use of sinus irrigation solutions should be further evaluated with regard to maintaining functional activity of cationic antimicrobial peptides involved in sinonasal innate immunity.; Charmaine M. Woods...

BACKGROUND AND OBJECTIVES: The effect of biocompatible peritoneal dialysis (PD) solutions on PD-related peritonitis is unclear. This study sought to evaluate the relationship between use of biocompatible solutions and the probability of occurrence or clinical outcomes of peritonitis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The study included all incident Australian patients receiving PD between January 1, 2007, and December 31, 2010, using Australia and New Zealand Dialysis and Transplant Registry data. All multicompartment PD solutions of neutral pH were categorized as biocompatible solutions. The independent predictors of peritonitis and the use of biocompatible solutions were determined by multivariable, multilevel mixed-effects Poisson and logistic regression analysis, respectively. Sensitivity analyses, including propensity score matching, were performed. RESULTS: Use of biocompatible solutions gradually declined (from 7.5% in 2007 to 4.2% in 2010), with preferential use among smaller units and among younger patients without diabetes mellitus. Treatment with biocompatible solution was associated with significantly greater overall rate of peritonitis (0.67 versus 0.47 episode per patient-year; incidence rate ratio, 1.49; 95% confidence interval [CI]...

Dans cette thèse, nous analysons les propriétés géométriques des surfaces obtenues des solutions classiques des modèles sigma bosoniques et supersymétriques en deux dimensions ayant pour espace cible des variétés grassmanniennes G(m,n). Plus particulièrement, nous considérons la métrique, les formes fondamentales et la courbure gaussienne induites par ces surfaces naturellement plongées dans l'algèbre de Lie su(n). Le premier chapitre présente des outils préliminaires pour comprendre les éléments des chapitres suivants. Nous y présentons les théories de jauge non-abéliennes et les modèles sigma grassmanniens bosoniques ainsi que supersymétriques. Nous nous intéressons aussi à la construction de surfaces dans l'algèbre de Lie su(n) à partir des solutions des modèles sigma bosoniques. Les trois prochains chapitres, formant cette thèse, présentent les contraintes devant être imposées sur les solutions de ces modèles afin d'obtenir des surfaces à courbure gaussienne constante. Ces contraintes permettent d'obtenir une classification des solutions en fonction des valeurs possibles de la courbure. Les chapitres 2 et 3 de cette thèse présentent une analyse de ces surfaces et de leurs solutions classiques pour les modèles sigma grassmanniens bosoniques. Le quatrième consiste en une analyse analogue pour une extension supersymétrique N=2 des modèles sigma bosoniques G(1...

Dans ce travail, nous adaptons la méthode des symétries conditionnelles afin de construire des solutions exprimées en termes des invariants de Riemann. Dans ce contexte, nous considérons des systèmes non elliptiques quasilinéaires homogènes (de type hydrodynamique) du premier ordre d'équations aux dérivées partielles multidimensionnelles. Nous décrivons en détail les conditions nécessaires et suffisantes pour garantir l'existence locale de ce type de solution. Nous étudions les relations entre la structure des éléments intégraux et la possibilité de construire certaines classes de solutions de rang k. Ces classes de solutions incluent les superpositions non linéaires d'ondes de Riemann ainsi que les solutions multisolitoniques. Nous généralisons cette méthode aux systèmes non homogènes quasilinéaires et non elliptiques du premier ordre. Ces méthodes sont appliquées aux équations de la dynamique des fluides en (3+1) dimensions modélisant le flot d'un fluide isentropique. De nouvelles classes de solutions de rang 2 et 3 sont construites et elles incluent des solutions double- et triple-solitoniques. De nouveaux phénomènes non linéaires et linéaires sont établis pour la superposition des ondes de Riemann. Finalement...

As equações semigeostrocas, introduzidas por Hoskins e Bretherton em 1972 em [20], sao um conjunto de equacoes que modelam fluxos atmosfericos/ oceanicos de larga escala. Elas possuem uma formulação em variaveis duais que se presta ao tratamento analítico. Alguns autores estudaram esta formulação, veja, por exemplo, [3], [14], [22], [12], [21],em particular obtendo existencia de solucões fracas em espaços de medidas. Contudo, ha dificuldades em converter soluções fracas da formulação dual em soluções fracas na formulação original, e portanto de interpretar fisicamente as soluções obtidas. Em [11], Culled e Feldman provaram a existencia de soluções Lagrangeanas para o sistema semigeostrofico em coordenadas fisicas com vorticidade potencial em Lp, p > 1. No presente trabalho estendemos os resultados de Cullen e Feldman para o caso limite p = 1 e estudamos o comportamento de sequencias de soluções Lagrangeanas correspondentes a uma sequencia de vorticidades potenciais iniciais convergindo fortemente em L1. Provamos que tais soluções Lagrangeanas convergem em L1 loc. Exibimos um contra-exemplo que sugere que nosso resultado não pode ser estendido para o espaço das medidas de Radon; The semigeostrophic equations...

The conformation of carboxymethylcellulose (CMC) in salt solutions was studied using viscometry, light scattering and gel permeation chromatography. From the viscosity data, the conformation of CMC in aqueous saline solutions was determined to be elliptical. At high ionic strengths, for example 2.5N NaCl, the macromolecule collapses upon itself. The gel permeation chromatography data indicated the presence of large molecular weight CMC particles (~2 x 109 daltons). The light scattering data also showed the presence of large CMC particles. The presence of large CMC particles explains the change in concentration dependence of the viscosity data between low and high CMC concentrations. Two species in solution, CMC molecules and CMC aggregates, each contribute to the observed viscosity. Both CMC molecules and aggregates, at low concentrations, show a linear relationship between viscosity and concentration, however, the slopes of the lines are different. A model is cited which provides an explanation of the viscous behavior of CMC in distilled water and salt solutions over time, based on solvation of CMC aggregates. This research suggests that the solvation time can be greatly reduced by autoclaving the solutions, thereby achieving an equilibrium viscosity.

This study was comprised of two related projects: a viscosity variability study and a trivalent cation study. For the first study, the dependence of viscosity of solutions of the polymer sodium carboxymethylcellulose (CMC) on temperature was quantitatively determined so that the viscosity measurements from four sets of viscosity versus age of solution data could be normalized. The four sets of age of solution data were obtained for two solutions containing Al cation and for two solutions containing Mg cation. The temperature normalization procedure proved viable. Factoring out the variability due to temperature led to a decrease in overall variability of the viscosity data of the three solutions for which temperature fluctuation had been problematic. The trivalent cation study involved addition of Al3+ or Cr3+ cation to solutions of CMC. The overall objective was to produce high viscosity CMC solutions by promoting crosslinking through the trivalent cations to anionic sites along the polymer chains. Addition of A1C13 solution to the CMC solution was ineffective: at low ionic strengths, polymer precipitated out of solution. To prevent precipitation it was necessary to deliver the trivalent cation more slowly. This was accomplished by adding trivalent cation either in combination with a chelating agent or already in the form of a metal complex. The chelating agents citric acid...

The fountain solutions used for lithographic offset printing are solutions combining several chemicals. Each consists of water, some weak acid, gum arabic and alcohol in some fountain solutions, and some additives such as a nitrate, phosphate, bichromate, etc. This paper is a study of using polysilicate material instead of gum arabic in lithographic fountain solutions. Also, to solve the problem of silicate gelation by using the proper ratio of chemicals. The gelling problem of silicate material may be affected by the concentration, pH value, organic solvents and impurities, etc. Any one of the above will make the silicate material gel faster or retard the gelation. Hence, the kind of chemicals used are very important to the properties of polysilicate fountain solutions. The amount of those chemicals in the polysilicate fountain solution is also important for the gelling time. By controlling the ratio of chemicals, the gelling problem was solved with retarding of gelation. A pilot test, run by using a non-linear programming package, was done before the experimentation. The gelling time was prolonged long enough for lithographic fountain solution use. A series of press tests was accomplished with a Chief 15 duplicator to affirm the possible usage of polysilicate fountain solutions. The press tests also proved the gelling problem does not exist on the running press. After using the ratio of chemicals found in this paper...