4 resultados para Captação de cálcio

em Repositório Institucional da Universidade Estadual de São Paulo - UNESP


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The objective of this study was to evaluate the effect of adding calcium ions and fluoride in the formulation of a whitening gel 35% hydrogen peroxide in its penetration through the dental structure, whitening efficacy and surface hardness of dental enamel. 80 teeth bovine incisors were used, which were obtained enamel and dentin disks of the buccal surface with 6mm diameter and 2mm thick (1 mm of enamel and dentin 1mm). The samples were divided into four groups stratified according to the protective substance / remineralizing added to the gel of hydrogen peroxide 35%: Group Ca - Calcium gluconate 0.5%; Group F - Sodium fluoride 0.2%; Group Ca + F - Calcium gluconate 0.5% and Sodium Fluoride 0.2%; Control group - no substance was added. The initial color of the samples and the hardness of the enamel were measured before the bleaching procedures. The specimens from each group were placed on a metallic support on which there was a simulated pulp chamber, which was filled with acetate buffer to collect and stabilize the penetrated peroxide. The respective bleaching treatments were applied 3 times, total of 30 minutes of application. The amount of peroxide which passed through the samples was determined by absorbance spectrophotometry. The hardness of the samples was measured immediately after bleaching. Next, the samples were immersed in artificial saliva for 7 days, after which the final color was evaluated. Data were statistically analyzed adopting a 5% significance level

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Water is an economic, strategic and social valuable resource of the utmost importance to society. This renewable natural resource is increasingly scarce with the growing of populations, industries and agriculture, in addition to the pollution surface and underground water and the waste have aggravated this situation. Investments in the sector of water resources so that this resource meets in quantity and quality the demand from its multiple uses, represent a significant portion of national and regional budgets. Therefore, the use of alternative sources of water capture can reduce the pressure on conventional public water supply systems. In this work was designed and executed a rain water collection system to a residence in the city of Barueri (SP), which can be applied to other residences. In this system, the rooftop of the residence was used as the waterproof and capture area. The gutter and the PVC conductors were used for driving the water to two connected reservoirs. The stored water was designed to address activities that are not potable, such as washing clothes and external areas and garden irrigation. The system showed economic viability, with 34-month return of investment time, wherein after that period, in addition to environmental and social benefits derived from the implementation of the project, the economy made with the payment of public supply rates should be considered. This rainwater capture system is inexpensive and uses materials available in the market. Therefore, its application to a greater number of households should be encouraged as a measure of sustainable water management