838 research outputs found
Romp as a versatile method for the obtention of differentiated polymeric materials
Ring Opening Metathesis Polymerization (ROMP) of cyclic olefins is a powerful transition metal-catalyzed reaction for syntheses of polymers and copolymers. The key feature of this reaction is the [2+2]-cycloaddition mechanism, with retention of the olefinic unsaturation in the polymer chain and occurrence of living polymerization. With the development of metal-carbene type catalysts for this process, many addressed polymeric materials have been successfully prepared to be employed in several fields of the science and technology. This review summarizes recent examples of syntheses of polymers with amphiphilic features such as block, graft, brush or star copolymers; as well syntheses of biomaterials, dendronized architectures, photoactive polymers, cross-linked or self-healing materials, and polymers from renewed supplies
Pesquisa de corpo inteiro com gálio-67 em uma paciente com paracoccidioidomicose: relato de caso
A 26 year-old female was admitted with abdominal pain, fever and weight loss. The clinical and laboratory investigations led to the diagnosis of paracoccidioidomycosis. Gallium-67 whole body images correlated well with the clinical course of the disease and with the patient's prognosis.Paciente do sexo feminino de 26 anos foi internada com dor abdominal, febre e emagrecimento. A investigação clÃnico-laboratorial estabeleceu o diagnóstico de paracoccidioidomicose. Os achados cintilográficos com citrato de gálio-67 correlacionaram-se com o curso clÃnico da paciente
Niobium and niobium-iron coatings on API 5LX 70 steel applied with HVOF
The present study aimed to create and characterize niobium and niobium-iron60% coatings applied to steel API 5L X70 using the hypersonic thermal spray process (HVOF). The morphologies of the coatings were analyzed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and profilometry, while the coatings’ hardnesses was evaluated using the Vickers hardness test. The coatings’ corrosion resistance was evaluated by monitoring their open circuit potential and potentiodynamic polarization and performing electrochemical impedance spectroscopy in a 0.05 M NaCl solution. The results showed that the niobium-iron coating contained minor porosity regions, while such defects occurred over large regions of the niobium coating. In terms of corrosion resistance, the coatings obtained in this work promoted a reduction in the substrate’s corrosion rate, but the presence of discontinuities such as porosity compromised the barrier effects of these coatings
Promovendo a saúde e a cidadania do idoso: o movimento das universidades da terceira idade
Excesso de peso em adolescentes e estado nutricional dos pais: uma revisão sistemática
Retrospective analysis of melanocytic lesions in children at the National Cancer Institute-RJ
Concentration by membrane separation processes of a medicinal product obtained from pineapple pulp
Efeito da solução de separação densimétrica na quantidade e qualidade da matéria orgânica leve e na quantificação do carbono orgânico da fração pesada
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