Obtenção e caracterização físico-química de blendas poliméricas, baseadas em POE e PMMA, dopadas com dióxido de titânio

The study of polymer blends has been an alternative method in the search field of new materials for obtaining materials with improved properties. In this work blends of poly(methyl methacrylate) (PMMA) and poly(ethylene oxide) (PEO) doped with titanium dioxide (TiO2) were studied. The PEO is a polymer semicrystalline structure varying between, 70 and 84% crystallinity, while the PMMA exhibits behavior amorphous in their structure. The use of TiO2 is related to corrosion-resistant of titanium as well as good heat transfer and other characteristics. The study of these polymer blends doped TiO2 gives the properties junction organic (polymer) and inorganic (oxide) which leads to modification of the properties of the resultant material. The blends were doped TiO2 (POE/PMMA/TiO2) in different proportions of the PMMA with the PEO and TiO2 fixed. The ratios were: 90/10/0,1; 85/15/0, 1; 80/20/0,1, 75/25/0,1 and 70/30/0,1. The resulting material was obtained in powder form and being characterized by Fourier Transformed Infrared (FTIR) Spectroscopy, Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and Electrochemical Impedance Spectroscopy (EIS). The infrared spectra (IR) for the blends in different ratios showed a band at 1744 cm-1, characteristic of the C=O stretching, which increases in intensity with increasing PMMA composition, while in the spectrum of pure PEO this band is absent. This may suggest that the interaction is occurring between the polymers. In the micrographs of the blends also observed change in their surfaces with variation of the composition of PMMA, contributing to the change of the electrical properties of the material. The EIS data showed that the material exhibited conductivity of the order of 10-6 S.cm-1. The blend in the ratio B2(85/15/0, 1) showed better conductivity, σ = 1.56 x 10-6 S.cm-1. It was observed that the diffusion coefficient for the blends, B5(70/30/0, 1) was the largest, 1.07 x 10-6 m2.s-1. The XRD data showing that, with the variation in the composition of the PMMA blend crystallinity of the material is decreased reaching a minimum B3(80/20/0,1), and then increases again. Thermal analysis suggests that blends made from the material obtained can be applied at room temperature

Preservação da veia safena magna na cirurgia de varizes dos membros inferiores

A veia safena magna autóloga é o melhor substituto arterial nas revascularizações dos membros inferiores, importante na revascularização do miocárdio e pode ser utilizada nas cirurgias do sistema venoso e nos traumas das extremidades. A fleboextração aumenta os riscos de lesões linfáticas e neurológicas. Assim, no tratamento das varizes primárias dos membros inferiores por meio da cirurgia ou de outras técnicas, a preservação da safena é recomendável se ela for normal ou apresentar alterações que ainda permitam sua preservação pela correção da causa desencadeante. Tal correção pode ser feita por técnicas cirúrgicas. Entre elas, a cura hemodinâmica da insuficiência venosa em ambulatório (CHIVA) tem mostrado bons resultados. Recentemente, um ensaio clínico randomizado e controlado foi publicado comprovando sua eficácia. Outra técnica bastante utilizada é a da ligadura rasante da junção safenofemoral + crossectomia + ligadura das tributárias de crossa, com a qual se tem obtido resultados contraditórios. Finalmente, as técnicas que corrigem a insuficiência da safena reparando as valvas ostial e pré-ostial (valvoplastia externa) são mais fisiológicas. Um ensaio clínico internacional multicêntrico, randomizado e controlado, testando um novo dispositivo, está sendo realizado, com resultados iniciais favoráveis. Este estudo pretende fazer uma revisão sobre as técnicas utilizadas na preservação da safena magna.

Eletromanometria do esfíncter superior do esôfago antes e após perfusão esofágica com ácido clorídrico 0,1N: estudo experimental no cão

Racional — A resposta do esfíncter esofágico superior ao refluxo gastroesofágico é controvertida. A perfusão esofágica com ácido clorídrico é modelo de estudo da ação do ácido o componente mais agressivo do refluxo sobre o esfíncter. Objetivos - Estudar o efeito da acidificação esofágica sobre o esfíncter esofágico superior através da eletromanometria esofágica. - Material e Métodos - em 30 cães adultos de ambos os sexos foram registrados estudos eletromanométricos do esôfago. A técnica utilizada foi a de puxada intermitente da sonda e perfusão contínua dos cateteres com água destilada. Estes exames permitiram as medidas da amplitude da pressão (mm Hg) e do comprimento (cm) do esfíncter superior do esôfago em condições basais (momento 1). Após esta fase, os animais foram submetidos a perfusão esofágica e divididos em 3 grupos de 10, na dependência da solução utilizada na perfusão e do momento do estudo: Grupo 1: perfusão esofágica com água destilada e estudos eletromanométricos realizados aos 15 minutos (momento 2) e 30 minutos (momento 3) do término da perfusão; Grupo 2: perfusão esofágica com HCl 0,1 N e estudos eletromanométricos realizados 15 minutos após o término da perfusão (momento 2); Grupo 3: perfusão esofágica com HCl 0,1 N e estudos eletromanométricos realizados 30 minutos após o término da perfusão (momento 3). Resultados/Conclusão - Os resultados observados permitiram concluir que a acidificação do esôfago não provocou alterações significativas sobre a amplitude de pressão e comprimento do esfíncter superior do esôfago.

O uso da informação contábil no setor sucroalcooleiro: um estudo nas indústrias de Alagoas

This study has the purpose of discussion and reflection of how the accounting information in the managemental area are used by the sugar & alcohol industry, located at State of Alagoas, aiming to identify if them please their managers expectations in the process of taking decision. Ahead of an existent universe of 27 (twenty seven) companies registered at the Sugar & Alcohol Labor Union of State of Alagoas SINDAÇUCAR files, were collected 14 (fourteen) questionnaires to support the current research classified as explorative and descriptive. The junction of these two kinds of research resulted in a quantitative and perceptive analysis of the use of the accounting information in the process of taking decision of the Sugar & Alcohol industry in Alagoas. The results demonstrated in this research indicate that, although the managers consider relevant the information at cost area, they do not use them in the process of taking decision. The reports emitted by accountancy are only financial, such as balance sheets, income statement, financial flow, among others factors. The importance order that the managers give to the accounting information and the kind of information that they use in the process of taking decision do not indicates that they use the accountancy in administration level. The statistics analysis of the files collected allows infer that the information provided by accountancy are considered important, however are few used at the manager process

A gestão participativa do desenvolvimento rural sustentável: o PRONAF na Subzona de Touros/ RN

To investigate the possibilities and limits of mechanisms of participativa management in the scope of the Pronaf - National Program of Fortalecimento of Familiar Agriculture, and the corresponding effectiveness of its actions in the construction of alternatives of sustainable agricultural development in the Coast North of the State of the Great River of the North, more specifically, in the composed Subzona de Touros for the cities of Bulls, White Well, Pureness, Is Miguel of the Gostoso and Taipu. To carry through this analysis they had been carried through Research of Field with the objective to reconstitute the trajectory of the CMDRS, to trace the profile of the citizens that compose each one of the five advice, its expectations, interests and the level of participation of the local population

Avaliação do potencial mutagênico da água do açude de Lucrécia (RN- Brasil): um enfoque na relação saúde e ambiente

The water quality of many reservoirs in the world has been reduced due to percolation of contaminants to water, which can have natural or anthropogenic origin, increasing the level of genotoxic compounds in aquatic ecosystems. This fact has contributed to the reduction of environmental quality, and commitment the health of living beings that inhabit these ecosystems, including the human population. In this backdrop of reduced water quality, is the Lucrecia dam, which is a major surface water reservoirs by volume of semi-arid region of Rio Grande do Norte, and that has shown contamination by heavy metals, cyanobacteria toxic and the natural presence of Radon. The population that use this source has been showing high rates of cancer, popularly associated with the consumption of this water, with a prevalence about three times higher compared to the whole state of Rio Grande do Norte. Based on this, the present study aimed to evaluate the mutagenic potencial of surface water from the Lucrecia dam, using the Micronucleus Test in Tradescantia pallida (Trad-MN) and in human peripheral blood lymphocytes (CBMN) assay, as well as identify the concentrations of some heavy metals in this water. Water samples were collected on a dry season and a rainy season, in two distinct points. Moreover, in order to bring a completely view about the relationship of man-health-environment in this local, through the knowledge of knowing / acting environmental from residents of Lucrecia, and the use and perceptions they have about the dam of your city, a study of Environmental Perception was carried out with local residents. The results obtained for the both micronucleus test, showed significant results for the three points analyzed. The strongest mutagenic effect was observed in the dry season for both assays. Chemical analyses detected an increase of heavy metal levels in different points and season above the maximum allowed by legislation. Regarding the study of Environmental Perception with local residents, it was observed the knowledge of the environment that the residents have, as well as the strong ties and perceptions with the dam of the city. Thus, the combination of these two aspects (the genetic toxicity tests conducted in the dam together with analysis of environmental perception with the residents of Lucrecia) allowed to draw a more complete diagnosis on the local situation

Análises clínicas, radiográfica e microscópica de molares permanentes sem ou com lesão de cárie na superfície oclusal

O presente trabalho, objetivou avaliar comparativamente o diagnóstico clínico, radiógráfico e histológico de molares permanentes humanos sem ou com lesão de cárie na superfície oclusa!. Vinte e quatro dentes que estavam armazenados em formalina a 10% foram selecionados e em seguida submetidos a um exame clínico, através da inspeção visual, onde foram separados em 3 grupos: grupo 1 (G1), formado por dentes hígidos; grupo 2(G2), por dentes com pigmento na superfície oclusal e grupo 3(G3), aqueles com lesão de cárie na oclusal. Este exame foi realizado com auxílio de luz artificial proveniente de um refletor odontológico, sem qualquer manipulação da superfície. Para cada dente foram realizados duas tomadas radiográficas com e sem tela milimetrada, no sentido vestibulo lingual por um dos avaliadores, simulando uma radiografia interproximal, onde o feixe incidiu perpendicular ao longo eixo do dente. Em seguida os dentes foram preparados histomorfologicamente para coloração com hematoxilina e eosina e análise microscópica. Pela avaliação dos resultados a partir da amostra de 100%, foi possível concluir: 1) Os dentes clinicamente considerados hígidos (G1) apresentaram radiograficamente 74,99% de ausência de imagem radiolúcida e em 25% presença desta imagem na Junção Amelo¬dentinária e microscopicamente ausência de cárie em 100%; 2) os dentes que clinicamente apresentaram fissura pigmentada' (G2) notou-se em 33,33%, ausência da imagem radiolúcida e em 66,66% presente esta imagem na junção amelodentinária, 100% de ausência de cárie através da análise microscópica; 3) clinicamente, os dentes que apresentaram lesão de cárie (G3), radiograficamente foram comprovados 100% de imagem radiolúcida sugestiva de cárie e microscopicamente dos 100% destas, foram considerados cáries rasa (16,66%), média (61,10%) e profunda (22,22%) respectivamente

Prevalência, classificação e características do refluxo cecoileal diagnosticado pelo enema opaco

OBJETIVO: Verificar, retrospectivamente, a prevalência do refluxo cecoileal diagnosticado pelo enema opaco, caracterizar sua distribuição etária e sexual e classificá-lo conforme o grau de intensidade. MATERIAIS E MÉTODOS: Foram revistos 715 enemas opacos, incluindo 268 homens e 447 mulheres com idade média de 54 anos. RESULTADOS: Dos 715 casos examinados, 46,5% apresentaram refluxo cecoileal, sendo 45% do tipo leve, 37,5% do tipo moderado e 17,5% do tipo severo. Refluxo cecoileal esteve presente em 48,3% das mulheres e em 43,6% dos homens. A distribuição percentual do refluxo cecoileal por faixa etária mostrou 46,1% nos indivíduos com menos de 21 anos, 42,1% nos indivíduos entre 21-40 anos, 49,8% nos indivíduos entre 41-60 anos e 44,7% nos indivíduos com mais de 60 anos. CONCLUSÃO: Refluxo cecoileal foi achado relativamente freqüente em nosso material, correspondendo os graus moderado e severo a 25% do material examinado. Aparentemente, não há associação entre seu surgimento e sexo ou idade. A etiopatogenia e conseqüências do refluxo cecoileal são ainda pouco conhecidas. Alguns estudos sugerem que o comprometimento de componentes da junção ileocecal, como os ligamentos, pode favorecer seu aparecimento. Entre as conseqüências prováveis, incluem-se a contaminação e alteração motora ileais, resultantes do material refluído do ceco.

O efeito da autocorrelação no desempenho do gráfico T2 de hotelling: caso bivariado

The chart of control of Hotelling T2 has been the main statistical device used in monitoring multivariate processes. Currently the technological development of control systems and automation enabled a high rate of collection of information of the production systems in very short time intervals, causing a dependency between the results of observations. This phenomenon known as auto correlation causes in the statistical control of the multivariate processes a high rate of false alarms, prejudicing in the chart performance. This entails the violation of the assumption of independence and normality of the distribution. In this thesis we considered not only the correlation between two variables, but also the dependence between observations of the same variable, that is, auto correlation. It was studied by simulation, the bi variate case and the effect of auto correlation on the performance of the T2 chart of Hotelling.

Predição em modelos de tempo de falha acelerado com efeito aleatório para avaliação de riscos de falha em poços petrolíferos

We considered prediction techniques based on models of accelerated failure time with random e ects for correlated survival data. Besides the bayesian approach through empirical Bayes estimator, we also discussed about the use of a classical predictor, the Empirical Best Linear Unbiased Predictor (EBLUP). In order to illustrate the use of these predictors, we considered applications on a real data set coming from the oil industry. More speci - cally, the data set involves the mean time between failure of petroleum-well equipments of the Bacia Potiguar. The goal of this study is to predict the risk/probability of failure in order to help a preventive maintenance program. The results show that both methods are suitable to predict future failures, providing good decisions in relation to employment and economy of resources for preventive maintenance.

Testes em modelos weibull na forma estendida de Marshall-Olkin

In survival analysis, the response is usually the time until the occurrence of an event of interest, called failure time. The main characteristic of survival data is the presence of censoring which is a partial observation of response. Associated with this information, some models occupy an important position by properly fit several practical situations, among which we can mention the Weibull model. Marshall-Olkin extended form distributions other a basic generalization that enables greater exibility in adjusting lifetime data. This paper presents a simulation study that compares the gradient test and the likelihood ratio test using the Marshall-Olkin extended form Weibull distribution. As a result, there is only a small advantage for the likelihood ratio test

Modelo de tempo de falha acelerado com fração de cura : uma abordagem unificada

In this work we study the accelerated failure-time generalized Gamma regression models with a unified approach. The models attempt to estimate simultaneously the effects of covariates on the acceleration/deceleration of the timing of a given event and the surviving fraction. The method is implemented in the free statistical software R. Finally the model is applied to a real dataset referring to the time until the return of the disease in patients diagnosed with breast cancer

Testes de hipóteses em modelos de sobrevivência com Fração de cura

Survival models deals with the modeling of time to event data. However in some situations part of the population may be no longer subject to the event. Models that take this fact into account are called cure rate models. There are few studies about hypothesis tests in cure rate models. Recently a new test statistic, the gradient statistic, has been proposed. It shares the same asymptotic properties with the classic large sample tests, the likelihood ratio, score and Wald tests. Some simulation studies have been carried out to explore the behavior of the gradient statistic in fi nite samples and compare it with the classic statistics in diff erent models. The main objective of this work is to study and compare the performance of gradient test and likelihood ratio test in cure rate models. We first describe the models and present the main asymptotic properties of the tests. We perform a simulation study based on the promotion time model with Weibull distribution to assess the performance of the tests in finite samples. An application is presented to illustrate the studied concepts

A distribuição F generalizada para selecionar modelos de sobrevivência com fração de cura

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Caracterização morfodinâmica do estuário do Rio Açu, Macau/RN

Estuaries are coastal environments ephemeral life in geological time, derived from the drowning of the shoreline as a function of elevation relative sea level. Such parallel systems is characterized by having two sources of sediment, the river and the sea. The study area comprises the Acu River estuary, located on the northern coast of Rio Grande do Norte State, in a region of intense economic activity, mainly focused on the exploration of oil onshore and offshore, likely to accidental spills. In the oil sector are developed for salt production, shrimp farming, agriculture, fisheries and tourism, which by interacting with sensitive ecosystems, such as estuaries, may alter the natural conditions, thus making it an area susceptible to contamination is essential in understanding the morphodynamic variables that occur in this environment to obtain an environmental license. Information about the submarine relief the estuaries are of great importance for the planning of the activity of environmental monitoring, development and coastal systems, among others, allowing an easy management of risk areas, and assist in the creation of thematic maps of the main aspects of landscape. Morphodynamic studies were performed in this estuary in different seasonal periods in 2009 to observe and quantify morphological changes that have occurred and relate these to the hydrodynamic forcing from the river and its interaction with the tides. Thus, efforts in this area is possible to know the bottom morphology through records of good quality equipment acquired by high resolution geophysical (side-scan sonar and profiler current by doppler effect). The combination of these data enabled the identification of different forms of bed for the winter and summer that were framed in a lower flow regime and later may have been destroyed or modified forms of generating fund scheme than the number according Froude, with different characteristics due mainly to the variation of the depth and type of sedimentary material they are made, and other hydrodynamic parameters. Thus, these features background regions are printed in the channel, sandy banks and muddy plains that border the entire area