638 resultados para Uniformidade de deposição


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The Boron Neutron Capture Therapy (BNCT), based on the 10B(n,α)7Li reaction, represents a promising modality for the treatment of cancers that are resistents to conventional treatments. So, it is necessary to find drugs (boron compounds) with high selectivity for each type of cancer, the neutrons source should be well characterized and the rate of 10B(n,α)7Li reaction should be measured with great accuracy as possible. This study aimed to develop a method for manufacturing thin films of boron, for measure the 10B(n,α)7Li reaction, and analyze the uniformity of the films. Five thin films of boron were manufactured with three different concentrations of boric acid, heated to transform the acid in boron, irradiated with thermic neutrons coupled to CR-39 detectors, in BNCT line at the reactor IEA-R1 IPEN/CNEN, São Paulo. After the irradiation, the detectors were chemically attacked with NaOH to reveal the tracks. The methodology presented is effective because it resulted in deposition of boron as thin film enabling the quantitative analysis of 10B(n,α)7Li reaction. The analysis of the uniformity of density of the induced tracks in CR-39 shows that, in most of the films, there is no uniformity in surface distribution of boron, but when the film is divided, we obtain some uniform sectors

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Radiotherapy in veterinary practice is already known and widely distributed in large specialized centers of developed countries. In early 2000, there were about 30 radiotherapy equipment specifically designed for the veterinary clinic in the United States. In Brazil, the veterinary radiotherapy is still confined to research in universities, where most of the procedures is radiation therapy performed with superficial x-ray machines, with a voltage between 50 and 150 kVp, focus-distance surface (DFS) between 20,0cm and 40,0cm. As that occurs in human medicine, new research strengthens the development and prospects for the use of radiotherapy as a safe option for treating cancer in animals. This paper presents a methodology for calculating the exposure time for superficial radiotherapy procedures in veterinary medicine for small animals (dogs and cats). The dosimetric parameters of X-rays are determined using a spreadsheet tool for Microsoft Office Excel, developed in this paper for a device Dermopan 2, Veterinary Hospital of UNESP in Araçatuba. Using the worksheet helps the veterinarian to determine the time of exposure to radiation determined for each clinical case, optimize the workflow for professionals in veterinary radiotherapy procedures, which often lack the medical physics in team and at the time of radiotherapy. The correct use of spreadsheet decreases the chances of errors in dose rates of radiation, providing a higher quality of care

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Titanium and its alloys has been widely used as materials for metallic biomaterials implants are usually employed to restore the hard tissue function, being used for artificial joints and bones, synthetic plates, crowns, dental implants and screws . Objective of this work was the surface modification of Ti-alloy 25Ta from biomimetic surface treatment of employment and deposition of polymer by electrospinning. The league was obtained from the fusion of the pure elements in the arc furnace with controlled atmosphere. The ingots were subjected to heat treatment, cold forged and sectioned discs with 13 mm diameter and 3 mm thick. Two surface treatments was evaluated, biomimetic and electrospinning with PCL fiber. The biomimetic treatment was performed involving alkaline treatment for three molarities 1.5M, 3M and 5M with immersion in SBF. The electrospinning was performed using PCL polymer alloy surface after the alkali treatment Ti25Ta 1M. For this group the polymer coated surfaces were immersed in calcium phosphate containing solution for immobilization of apatite. The results were compared with previous studies using surface treatment group to verify hydroxyapatite formation on the sample surface and it is concluded that the best condition is biomimetic treatment with 5M alkali treatment and heat treatment at 80 ° C for 72 hours

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Pós-graduação em Engenharia Mecânica - FEG

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From the last decade of the twentieth century, the rapid growth of nanotechnology has resulted in the discovery of a number of forms of nanoparticles and nanoclusters. We can cite as an example: nanotubes, nanowires, nanobelts, and nanoconesnanoclusters which have a wide range of applications, particularly as catalysts magnetic material nanodevices, chemical sensors, degradation of toxic chemicals, or even as possible carriers for the isotope medical applications.. The first step is the production and characterization of nanowires multithreaded using different types of metals (nickel, silver, gold) and polymers (pyrrole), which are prepared by electrochemical deposition process. Will be held by the characterization of the same images of scanning electron microscopy (SEM) and transmission electron microscopy (TEM)

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O trabalho teve como objetivo o desenvolvimento de uma metodologia de avaliacao qualitativa e quantitativa, com o uso de substancia tracadoras, nos estudos de deposicao em pulverizacao, com a possibilidade de variacao da tensao superficial da calda. Plantas de citros foram pulverizadas com solucao tracadora composta pelo corante Azul Brilhante na concentracao de 0,15% em mistura com o Saturn Yellow tambem a 0,15%, suspenso com o lignosulfonato Vixilperse a 0,015%. A pulverizacao foi realizada com turboatomizador Jacto, na velocidade de deslocamento de 2,8 km/h e volume de calda de 1830 L/ha. A tensao superficial da solucaotracadora pulverizada foi ajustada para 72,6 mN/m, mesma da agua, e com a reducao para 36,5 mN/m. Para as avaliacoes dos depositos, dividiu-se a planta em 12 setores, partes baixa, media e alta, coletando-se amostras nas partes externa e interna e nas posicoes frontal e perpendicular a pulverizacao. Em cada posicao de coleta na planta foram retiradas duas amostras de folhas, uma constituida de 10 folhas para avaliar a distribuicao e o deposito total de ambas as superficies das folhas, e outra com 6 folhas para avaliar a relacao do deposito individual entre as superficies inferior (abaxial) e superior (adaxial) das folhas. O escorrimento de calda para o solo foi avaliado colocando-se placas de petri, distanciadas de 20 cm entre si e linearmente, sob a projecao da copa, nos setores frontal e perpendicular a pulverizacao. Para cada tensao superficial testada coletou-se amostras em 5 plantas, considerando-se cada planta uma repeticao. A avaliacao qualitativa foi feita atraves da visualizacao da distribuicao do deposito sob luz ultravioleta e a determinacao da quantidade depositada atraves da espectrofotometria. A metodologia desenvolvida mostrou-se adequada para avaliacao dos depositos de pulverizacoes no campo, com a solucao tracadora, pela possibilidade de avaliar qualitativa e quantitativa

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)