5 resultados para Entropia Relativa
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
Compounded medicines have been reported by the ANVISA due to decreased of the therapeutic response or toxicity of these formulations. The aim of this work was to investigate the physicochemical quality control among naproxen sodium oral suspensions 25 mg/mL obtained from six compounding pharmacies (A, B, C, D, E and F) and the manufactured suspension (R). In the quality control test, the tests of pH, content, homogeneity, volume and physical and organoleptic characteristics were performed according to the Brazilian Pharmacopoeia. The analytical method for determination of naproxen in suspensions was validate. This method showed excellent precision, accuracy, linearity and specificity. In the content test the suspensions B, C and E showed lower value and the F suspension showed a high value of the content. The products C and E were disapproved in the description of the physical and organoleptic characteristics test. In the pH test, three suspensions were outside specifications (C, E and F). Only the products R, A and D showed satisfactory results in these tests and therefore they were approved for relative bioavailability test. The R, A and D suspensions were orally administered to Wistar rats and the blood samples were taken at time intervals of 10, 20, 40, 60 min, 3, 4, 6, 24 and 48 h. The plasma samples were immediately stored at 80 ºC until analysis of HPLC. The bioanalytical method validation showed specificity, linearity (R2 0.9987), precision, accuracy, good recovery and stability. The chromatographic conditions were: flow rate of 1.2 mL.min-1 with a mobile phase of acetonitrile : sodium phosphate buffer pH 4.0 (50:50, v/v) at 280 nm, using a C18 column. The confidence interval of 90% for the Cmax and AUCt ratio was within the range of 80 - 125% proposed by the FDA. Only one suspension, obtained from the compounding pharmacy D, was considered bioequivalent to the rate of absorption under the conditions proposed by this study. Thus, the results indicate the need for strict supervision from the relevant authorities to ensure the patient safety and the quality of compounded drugs by pharmacies
Resumo:
The rational construction necessary to systematize scientific knowledge in physics, introduces difficulties of understanding in some of its concepts. One of these concepts which exemplify properly this difficulty in learning or teaching is entropy. This thesis propose the construction of a didactic route which constitute itself a historical and epistemological course to entropy, intending to contribute for teaching this concept as well as other physics concepts. The basic assumption to build this route is that through the historical review of the development of this concept in the way suggested by Bachelard s (1884-1962) epistemology it is possible to make subjects, to be taught and learned, more meaningful. Initially I composed a brief biographical note to give the reader an idea about the issues, interests and reflections, related to science, and how I dealt with them in my private and professional life, as well as the role they played to lead me to write this thesis. The strategy to construct the route to entropy was to split the usual contents of basic thermodynamics in three moments in a way they can constitute epistemological units , which can be identified by the way of thinking in the corresponding moments of scientific knowledge production: a technical and empiricist moment, a rationalist and positivist moment and a post-positivist rationalist one. The transition between each moment is characterized by a rupture with the former way of thinking; however the progress in the construction of knowledge in the area is evident. As the final part of this work I present an analysis based on elements of Bachelard s epistemology that are present in each moment. This analysis is the basic component of the didactic route that I propose myself to build. The way I made this route guide to entropy could contribute to the construction of other didactic routes in physics and other sciences, in a way to unveil hidden meanings and as a tool to humanize scientific knowledge.
Resumo:
A posição que a renomada estatí stica de Boltzmann-Gibbs (BG) ocupa no cenário cientifíco e incontestável, tendo um âmbito de aplicabilidade muito abrangente. Por em, muitos fenômenos físicos não podem ser descritos por esse formalismo. Isso se deve, em parte, ao fato de que a estatística de BG trata de fenômenos que se encontram no equilíbrio termodinâmico. Em regiões onde o equilíbrio térmico não prevalece, outros formalismos estatísticos devem ser utilizados. Dois desses formalismos emergiram nas duas ultimas décadas e são comumente denominados de q-estatística e k-estatística; o primeiro deles foi concebido por Constantino Tsallis no final da década de 80 e o ultimo por Giorgio Kaniadakis em 2001. Esses formalismos possuem caráter generalizador e, por isso, contem a estatística de BG como caso particular para uma escolha adequada de certos parâmetros. Esses dois formalismos, em particular o de Tsallis, nos conduzem também a refletir criticamente sobre conceitos tão fortemente enraizados na estat ística de BG como a aditividade e a extensividade de certas grandezas físicas. O escopo deste trabalho esta centrado no segundo desses formalismos. A k -estatstica constitui não só uma generalização da estatística de BG, mas, atraves da fundamentação do Princípio de Interação Cinético (KIP), engloba em seu âmago as celebradas estatísticas quânticas de Fermi- Dirac e Bose-Einstein; além da própria q-estatística. Neste trabalho, apresentamos alguns aspectos conceituais da q-estatística e, principalmente, da k-estatística. Utilizaremos esses conceitos junto com o conceito de informação de bloco para apresentar um funcional entrópico espelhado no formalismo de Kaniadakis que será utilizado posteriormente para descrever aspectos informacionais contidos em fractais tipo Cantor. Em particular, estamos interessados em conhecer as relações entre parâmetros fractais, como a dimensão fractal, e o parâmetro deformador. Apesar da simplicidade, isso nos proporcionará, em trabalho futuros, descrever estatisticamente estruturas mais complexas como o DNA, super-redes e sistema complexos
Resumo:
Various physical systems have dynamics that can be modeled by percolation processes. Percolation is used to study issues ranging from fluid diffusion through disordered media to fragmentation of a computer network caused by hacker attacks. A common feature of all of these systems is the presence of two non-coexistent regimes associated to certain properties of the system. For example: the disordered media can allow or not allow the flow of the fluid depending on its porosity. The change from one regime to another characterizes the percolation phase transition. The standard way of analyzing this transition uses the order parameter, a variable related to some characteristic of the system that exhibits zero value in one of the regimes and a nonzero value in the other. The proposal introduced in this thesis is that this phase transition can be investigated without the explicit use of the order parameter, but rather through the Shannon entropy. This entropy is a measure of the uncertainty degree in the information content of a probability distribution. The proposal is evaluated in the context of cluster formation in random graphs, and we apply the method to both classical percolation (Erd¨os- R´enyi) and explosive percolation. It is based in the computation of the entropy contained in the cluster size probability distribution and the results show that the transition critical point relates to the derivatives of the entropy. Furthermore, the difference between the smooth and abrupt aspects of the classical and explosive percolation transitions, respectively, is reinforced by the observation that the entropy has a maximum value in the classical transition critical point, while that correspondence does not occurs during the explosive percolation.
Resumo:
Various physical systems have dynamics that can be modeled by percolation processes. Percolation is used to study issues ranging from fluid diffusion through disordered media to fragmentation of a computer network caused by hacker attacks. A common feature of all of these systems is the presence of two non-coexistent regimes associated to certain properties of the system. For example: the disordered media can allow or not allow the flow of the fluid depending on its porosity. The change from one regime to another characterizes the percolation phase transition. The standard way of analyzing this transition uses the order parameter, a variable related to some characteristic of the system that exhibits zero value in one of the regimes and a nonzero value in the other. The proposal introduced in this thesis is that this phase transition can be investigated without the explicit use of the order parameter, but rather through the Shannon entropy. This entropy is a measure of the uncertainty degree in the information content of a probability distribution. The proposal is evaluated in the context of cluster formation in random graphs, and we apply the method to both classical percolation (Erd¨os- R´enyi) and explosive percolation. It is based in the computation of the entropy contained in the cluster size probability distribution and the results show that the transition critical point relates to the derivatives of the entropy. Furthermore, the difference between the smooth and abrupt aspects of the classical and explosive percolation transitions, respectively, is reinforced by the observation that the entropy has a maximum value in the classical transition critical point, while that correspondence does not occurs during the explosive percolation.