930 resultados para Erythrocytic osmotic fragility


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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With advances in health care, has been na increase of demand for material that could replace the functions of the human body parts, thus evolved biomedic prosthesis which today are responsible for the constant improvement of the quality of life. The Titanium alloys are widely used as implants due to its properties, like high mechanical resistance, biocompatibility and corrosion resistance, and the addition alloying elements like Zirconium, may improve some of those properties. Such properties are related to the microstructure and consequently to the type of processing performed. The purpose of this dissertation was to characterize the experimental alloy Ti15Zr after route of processsing and heat treatment in order to extend the knowledge about this alloy. The latter has been abtained by fusion of pure metals in a arc melting furnace with an inert argon atmosphere. The material has been homogenized in a tube furnace at 950ºC for 24h and cold worked by swaging, after that, bars with 10 mm of diameter were obtained by the process of rotary forging. The samples were solubilized at 900º C for 2 hours and quenched in water. After that, 4 samples were submitted to the aging, at 400º C, 450º C, 500º C and 550º C. The microstructure and phase analysis was done by optical microscopy and X-rays diffraction (XRD), the mechanical characterization was carried out by microhardness test and finally, evaluation of corrosion resistance of the alloy by electrochemical tests. The XRD and the optical microscopy made it possible to analyze that the heat treatment influenced the phase shifting from α to α', and probably affected the alloy hardness, at the first aged sample at 500º Chas been a sudden increase in the value of hardness, probably by appearance of omega phase, unwanted phase to the medical application duo to great fragility, and finally ... (Complete abstract click electronic access below)

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Pós-graduação em Agronomia (Proteção de Plantas) - FCA

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With advances in health care, has been na increase of demand for material that could replace the functions of the human body parts, thus evolved biomedic prosthesis which today are responsible for the constant improvement of the quality of life. The Titanium alloys are widely used as implants due to its properties, like high mechanical resistance, biocompatibility and corrosion resistance, and the addition alloying elements like Zirconium, may improve some of those properties. Such properties are related to the microstructure and consequently to the type of processing performed. The purpose of this dissertation was to characterize the experimental alloy Ti15Zr after route of processsing and heat treatment in order to extend the knowledge about this alloy. The latter has been abtained by fusion of pure metals in a arc melting furnace with an inert argon atmosphere. The material has been homogenized in a tube furnace at 950ºC for 24h and cold worked by swaging, after that, bars with 10 mm of diameter were obtained by the process of rotary forging. The samples were solubilized at 900º C for 2 hours and quenched in water. After that, 4 samples were submitted to the aging, at 400º C, 450º C, 500º C and 550º C. The microstructure and phase analysis was done by optical microscopy and X-rays diffraction (XRD), the mechanical characterization was carried out by microhardness test and finally, evaluation of corrosion resistance of the alloy by electrochemical tests. The XRD and the optical microscopy made it possible to analyze that the heat treatment influenced the phase shifting from α to α', and probably affected the alloy hardness, at the first aged sample at 500º Chas been a sudden increase in the value of hardness, probably by appearance of omega phase, unwanted phase to the medical application duo to great fragility, and finally ... (Complete abstract click electronic access below)

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Pós-graduação em Agronomia (Proteção de Plantas) - FCA

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Dapsone use is frequently associated to hematological side effects such as methemoglobinemia and hemolytic anemia, which are related to N-hydroxylation mediated by the P450 enzyme system. The aim of the present study was to evaluate the influence of L-arginine supplementation, a precursor for the synthesis of nitric oxide, as single or multiple dose regimens on dapsone-induced methemoglobinemia. Male Wistar rats were treated with L-arginine at 5, 15, 30, 60 and 180 mg/kg doses (p.o., gavage) in single or multiple dose regimens 2 hours prior to dapsone administration (40 mg/kg, i.p.). The effect of the nitric oxide synthase inhibitor L-NAME was investigated by treatment with multiple doses of 30 mg/kg (p.o., gavage) 2 hours before dapsone administration. Blood samples were collected 2 hours after dapsone administration. Erythrocytic methemoglobin levels were assayed by spectrophotometry. The results showed that multiple dose supplementations with 5 and 15 mg/kg L-arginine reduced dapsone-induced methemoglobin levels. This effect is mediated by nitric oxide formation, since the reduction in methemoglobin levels by L-arginine is blocked by simultaneous administration with L-NAME, a nitric oxide synthase inhibitor.

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Membranes of Poly(2,5-benzimidazole) (ABPBI), prepared by polycondensation in polyphosphoric acid, were characterized from the fuel cell application point of view: mechanical properties of the membranes for different acid doping levels, thermal stability, permeability for the different gases/vapors susceptible of use in the cell (hydrogen, oxygen, methanol and ethanol), electro-osmotic water drag coefficient, oxidation stability to hydroxyl radicals, phosphoric acid leaching rate and, finally, in-plane membrane conductivity. ABPBI membranes presented an excellent thermal stability, above 500 degrees C in oxygen, suitable mechanical properties for high phosphoric acid doping levels, a low methanol and ethanol limiting permeation currents, and oxygen permeability compared to Nafion membranes, and a low phosphoric acid leaching rate when exposed to water vapor. On the contrary, hydrogen permeation current was higher than that of Nafion, and the chemical stability was very limited. Membrane conductivity achieved 0.07 S cm(-1) after equilibration with a humid environment. Fuel cell tests showed reasonable good performances, with a maximum power peak of 170 mW cm(-2) for H-2/air at 170 degrees C operating under a humidified hydrogen stream, 39.9 mW cm(-2) for CH3OH/O-2 at 200 degrees C for a methanol/water weight ratio of 1: 2, and 31.5 mW cm(-2) for CH3CH2OH/O-2 at the same conditions than for methanol. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.014207jes] All rights reserved.

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Based on a structured literature review, the ceramic tiles sector of Italy (benchmark) and Brazil (2nd world producer and consumer) are compared, under four strategic factors: normative, market, technology and strategic management, in order to identify critical risks for a national strategic sector. The document aims to propose guidelines for a strategic re-planning of the Brazilian ceramic tiles sector, making the Brazilian producers aware of the national market fragility (in spite of its recent remarkable evolution) and helping the policy makers to reflect on the need of reviewing the strategic planning methods and practice, of designing new targeted programs (based on coherence between operation and business strategies), of providing improved management to strengthen the sector against unfair competition by low-cost producers, enhancing the necessary infrastructure in technology, work, marketing and quality management. The analysis is limited to the single-firing production technology. The wide-coverage strategic analysis of the Brazilian ceramic tiles sector, very little studied until now in a scientific way, emphasizes the importance of applying research methodology and may be valuable to both scholars and practitioners. Additionally, it highlights the need of investments in innovation (product design and production technology) and the fundamental role of the sector organization, identifying different dimensions. It is possible to conclude that the recent Brazilian production growth is not due to a natural strengthening because of the hit of the sector and of correct enterprises strategy, but it seems the result of a temporary and favorable economic contingency.

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The filter paper method is one of the most commonly used and critiqued techniques for measuring soil suction. However, many aspects related to its use still require some clarification. The results of a comprehensive study on the effect of the contact between the soil grains and soil water and the filter paper are presented herein. We investigated the influence of the equilibration time, the texture of the porous material and the degree of contact, or lack thereof, between the soil grains and the filter paper using Miamian #42 and three different types of porous material. To enhance the difference between the total suction and the matrix suction, osmotic suction was induced by saturating the specimens with a sodium chloride solution.

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The Brazilian Atlantic forest has been an excellent laboratory for investigations regarding tropical forest ecology and the fragility of tropical ecosystems in face of human disturbances. In this article, we present a synthesis about the spatial distribution of Atlantic forest biodiversity and forest response to human disturbances, as well as the ongoing conservation efforts based on a review of several investigations in this biota. In general, studies have documented an uneven distribution of biodiversity throughout the Atlantic forest region, revealing alarming rates of habitat loss at low altitudes, while protected areas concentrate at higher altitudes. It has been suggested that the remaining forest habitat is moving towards an early-successional systems across human-modified landscapes. Such regressive forest succession increases the threats for several animals and plant groups. Based on these findings, we propose seven guidelines in order to enhance the provision of ecosystem services and the conservation value of human-modified landscapes, reducing the species extinction risk in the Atlantic forest and in other irreplaceable tropical biotas.

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ADOLESCENCE AND DRUG USE THROUGH THE LENS OF PSYCHOANALYSIS: SUFFERING AND ECSTASY IN THE PASSAGE The purpose of this study is to reflect upon the psychological factors of adolescent drug addiction according to a psychoanalytic perspective. First we consider adolescence as a social-historical category and then we discuss the psychoanalytic understanding of the adolescent transition. This theoretical path builds the approach that considers drug use as a phenomenon that serves as a passage ritual to contemporary adolescence. This phenomenon is modulated by the drive organization, which determines how the individual will take ownership of the use of psychoactive substances. We conclude that the substance use may function as a buffer-object, activated to deal with the structural fragility of the contemporary affective bonds.