999 resultados para Tomografia por Emissão de Pósitrons
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The ability to tridimensionally evaluate pathological and anatomical areas, in apical surgery planning, presents a number of advantages. Cone beam computed tomography (CBCT) was developed for dental applications. This paper aims to present a literature review on CBCT, highlighting its advantages over both conventional computed tomography (CT) and radiography. Moreover, its clinical applications in apical surgery are discussed. LITERATURE REVIEW AND CONCLUSION: Unlikely CT, CBCT captures a volume of data in a single 360º rotation, providing benefits such as higher accuracy, better resolution, reduced scanning time and reduced radiation dose. In the maxillofacial region, CBCT has been mainly used in the assessment of dento-alveolar pathology and oral traumatology. CBCT provides a better diagnosis and quantitative information on periodontal bone levels than conventional radiography. It has also been used for patients requiring surgical facial reconstruction, orthognathic surgery, dental implants, and more complex tooth extractions. Besides that, it seems to be a significant tool in modern endodontic practice, presenting useful applications in apical surgery.
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Pós-graduação em Cirurgia Veterinária - FCAV
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Pós-graduação em Química - IBILCE
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Soil tillage is one of the agricultural practices that may contribute to increase the loss of carbon through emission of CO2 (FCO2). The aim of this study was to investigate the effect of three soil tillage systems on FCO2, soil temperature and soil moisture in a sugarcane area under reform. The experimental area consisted of three tillage plots: conventional tillage (CT), conventional subsoiling (CS), and localized subsoiling (LS). FCO2, soil temperature and soil moisture were measured over a period of 17 days. FCO2 showed the highest value in CT (0.75 g CO2 m(-2) h(-1)). Soil temperature presented no significant difference (p > 0.05) between LS (26.2 degrees C) and CS (25.9 degrees C). Soil moisture was higher in LS (24%), followed by CS (21.8%) and CT (18.3%). A significant correlation (r = -0.71; p < 0.05) between FCO2 and soil temperature was observed only in CT. The conventional tillage presented a total emission (2,864.3 kg CO2 ha(-1)) higher than the emissions observed in CS (1,970.9 kg CO2 ha(-1)) and LS (1,707.7 kg CO2 ha(-1)). The conversion from CT to LS decreased soil CO2 emissions, reducing the contribution of agriculture in increasing the concentration of greenhouse gases in the atmosphere.
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Pós-graduação em Física - IFT
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Introduction: The request of three-dimensional images (3D) of the dentomaxillofacial complex has increased. Hence, new possibilities for assessment, treatment as well as follow-up after treatment have increased their importance with the use of cone beam computed tomography (CBCT). The images in two dimensions (2D) have inherent problems that can be solved with treedimensional images assessment. Objectives: To clarify the main doubts about the operational mechanism of complementary diagnostic method; to explain the advantages and disadvantages, to discuss the effective radiation dose and possible applications in orthodontia. Conclusion: The information generated by 2D images from the CBCT does not show differences that may endanger the orthodontic planning when compared with the images of 2D conventional radiographs. The effective radiation dose received by the patient should not be considered as a limiting factor of the tomography exam request.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Para a realização deste experimento, foram utilizados um rebolo de óxido de alumínio instalado em uma retificadora plana, um dispositivo em forma de balança juntamente com o sensor de deslocamento, um sistema de aquisição de sinais e um dressador de ponta única de diamante. O processamento digital dos dados foi obtido com o software Matlab. Nos ensaios, foram aplicados diferentes graus de recobrimento e profundidade de dressagem e comparada a agressividade obtida. A partir dos dados resultantes, os parâmetros RMS, DPO e DPKS mostraram-se bons indicadores para a operação. Também ficou comprovado que para recondicionar e definir novas características para o rebolo é necessária a remoção de 120 um. Do estudo do espectro do dinal de EA, notou-se que não há componentes hormônicas com frequência superior a 200 KHz.
Emissão de CO2 em um latossolo vermelho coberto com palha sob aplicação de efluente e lodo de esgoto
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Pós-graduação em Agronomia (Ciência do Solo) - FCAV
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Pós-graduação em Zootecnia - FCAV
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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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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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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)