Effects of stirring time and cooling rate on the rheocast microstructure and mechanical properties of magnesium alloy MRI 230D

Semisolid state processing is a methodology that transforms dendritic as-cast microstructure into globular non-dendritic microstructure with optimized mechanical properties. Rheocasting process involves mechanically stirring metals in a semisolid state and its benefits are associated with processing parameters. In order to evaluate stirring time effects, magnesium alloy MRI 230D (Mg–Al6.45–Ca2.25– Mn0.27–Sr0.25–Sn0.84) was melted and cooled down to semisolid processing temperature (595ºC). Moreover, isothermal stirring was executed for 1, 2, 4 and 8 minutes. In each experiment, cylindrical samples with different diameters (6 and 12 mm) were collected to evaluate cooling rates effects. The microstructure was analyzed through optical and electron microscopes. The results showed that in the longest stirring times, the primary α-Mg phase got coarser and the interglobular region became more refined. Although shape factor initially increased, subsequently there was a tendency to stabilize. Regarding cooling conditions, it was found that the interglobular region became more refined at higher cooling rates. Mechanical tests revealed an initial decrease in ultimate tensile strength (UTS) and ductility, but afterwards increased due to a more regular microstructure and superior shape factor. The 8-minutes stirring sample achieved the best results: an increase of 12% in UTS and 16% in ductility

Comparison of the efficacy of transforaminal and interlaminar radicular block techniques for treating lumbar disk hernia

AbstractObjectiveTo compare the interlaminar and transforaminal block techniques with regard to the state of pain and presence or absence of complications.MethodThis was a randomized double-blind prospective study of descriptive and comparative nature, on 40 patients of both sexes who presented lumbar sciatic pain due to central-lateral or foraminal disk hernias. The patients had failed to respond to 20 physiotherapy sessions, but did not present instability, as diagnosed in dynamic radiographic examinations. The type of block to be used was determined by means of a draw: transforaminal (group 1; 20 patients) or interlaminar (group 2; 20 patients).ResultsForty patients were evaluated (17 males), with a mean age of 49 years. There was a significant improvement in the state of pain in all patients who underwent radicular block using both techniques, although the transforaminal technique presented better results than the interlaminar technique.ConclusionBoth techniques were effective for pain relief and presented low complication rates, but the transforaminal technique was more effective than the interlaminar technique

Avaliação da Qualidade de Vida Em pacientes Submetidos A Tratamento Cirúrgico Para Escoliose Idiopática Do Adolescente, De Acordo Com A Última Vértebra Instrumentada

Objective: Evaluate the influence of the last instrumented vertebra on the quality of life of patients undergoing surgical treatment for adolescent idiopathic scoliosis. Methods: This is a retrospective and cross-sectional study, with level 4 of evidence. For this evaluation, the SRS-22r questionnaire was applied. The variables sex, age at the date of surgery, number of instrumented vertebrae and last instrumented vertebrae were correlated with the domains of the SRS-22r questionnaire. Results: 39 patients were evaluated, 33 (84.6%) of whom were female, with a mean age of 14.5 years at the date of surgery. All patients were introduced to arthrodesis posteriorly and instrumented with pedicle screws. The last instrumented vertebrae were D12, L1, L3 and L4. The average number of instrumented vertebrae was 11.9. There was no statistical significance in the correlation between the variables gender and the last instrumented vertebra with quality of life. The correlation between the variable number of instrumented vertebrae and the function / activity domain, as well as the correlation between the variable age at the date of surgery and the satisfaction with the treatment domain, presented statistical significance. Conclusion: The last instrumented level does not seem to interfere with quality of life, although patients with less instrumented levels had better scores in the function / activity domain.Objetivo: Avaliar a influência da última vértebra instrumentada na qualidade de vida de pacientes submetidos a tratamento cirúrgico para escoliose idiopática do adolescente. Métodos: Trata-se de um estudo retrospectivo e transversal do tipo série de casos, com nível IV de evidência. Para essa avaliação, aplicou-se o questionário SRS-22r. Foram correlacionadas as variáveis sexo, idade na data da cirurgia, número de vértebras instrumentadas e última vértebra instrumentada com os domínios do questionário SRS-22r. Resultados: Foram avaliados 39 pacientes, sendo 33 (84,6%) do sexo feminino, com idade média de 14,5 anos na data da cirurgia. Todos foram submetidos à artrodese por via posterior e instrumentação com parafusos pediculares. As últimas vértebras instrumentadas foram D12, L1, L3 e L4. Não houve significância estatística na correlação entre as variáveis sexo e última vértebra instrumentada com a qualidade de vida. A correlação entre a variável número de vértebras instrumentadas e o domínio função/atividade, assim como a correlação entre a variável idade na data da cirurgia e o domínio satisfação com o tratamento apresentaram significância estatística. Conclusão: O último nível instrumentado não parece interferir na qualidade de vida, embora pacientes com menos níveis instrumentados tenham apresentado melhor pontuação no domínio função/atividade

Por uma agenda racial de pesquisa em informação e comunicação em saúde

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Notch signaling regulates metabolic heterogeneity in glioblastoma stem cells.

Glioblastoma (GBM) stem cells (GSCs) reside in both hypoxic and vascular microenvironments within tumors. The molecular mechanisms that allow GSCs to occupy such contrasting niches are not understood. We used patient-derived GBM cultures to identify GSC subtypes with differential activation of Notch signaling, which co-exist in tumors but occupy distinct niches and match their metabolism accordingly. Multipotent GSCs with Notch pathway activation reside in perivascular niches, and are unable to entrain anaerobic glycolysis during hypoxia. In contrast, most CD133-expressing GSCs do not depend on canonical Notch signaling, populate tumors regardless of local vascularity and selectively utilize anaerobic glycolysis to expand in hypoxia. Ectopic activation of Notch signaling in CD133-expressing GSCs is sufficient to suppress anaerobic glycolysis and resistance to hypoxia. These findings demonstrate a novel role for Notch signaling in regulating GSC metabolism and suggest intratumoral GSC heterogeneity ensures metabolic adaptations to support tumor growth in diverse tumor microenvironments

Microstructural evolution of the magnesium alloy MRI 230D submitted to different processing routes in a semisolid state : SIMA and Rheocast

O processamento em estado semissólido visa obter uma microestrutura com grãos globulares, refinados e com propriedades isotrópicas, que tende a apresentar melhores propriedades mecânicas que a morfologia bruta de fusão. A liga de magnésio MRI 230D (Mg–Al6,45–Ca2,25–Mn0,27–Sr0,25–Sn0,84), de alta resistência à fluência, foi submetida a diferentes rotas de processamento em estado semissólido, SIMA (Strain Induced Melt Activation) e Reofundição, com o objetivo de avaliar a influência dos processos na microestrutura da liga. Para a rota SIMA a liga foi previamente laminada, em passe único com deformação de 8%, na temperatura de 250 °C. Posteriormente, a liga foi tratada termicamente nas temperaturas de 540 °C e 570 °C, nos tempos de 40 e 60 minutos. Na reofundição o material foi fundido a 660 °C e lentamente resfriado até a temperatura de processamento (595 °C), e então agitado mecanicamente. Os tempos de agitação variaram de 0 (sem agitação), 1, 2, 4 e 8 minutos. Os resfriamentos, em ambos os processos, foram realizados por imersão em água (25 °C). As amostras foram analisadas por microscopia óptica e eletrônica para avaliação da microestrutura, assim como analisadas termicamente. Os resultados mostraram a formação de grãos com maior fator de forma no processo SIMA além de uma morfologia mais grosseira e homogênea do que pelo processo de reofundição.Processing in a semisolid state aims to obtain a microstructure with globular, refined grains and isotropic properties, which tends to present better mechanical properties than as cast morphology. The magnesium alloy MRI 230D (Mg–Al6.45– Ca2.25–Mn0.27–Sr0.25–Sn0.84) was submitted to different processing routes in a semi-solid state, SIMA (Strain Induced Melt Activation) and Rheocasting, to evaluate the influence of these processes on the alloy microstructure. For the SIMA route, the alloy was previously laminated, in single pass with 8% deformation, at the temperature of 250 °C. Subsequently, it was heat treated at different temperatures (540 °C and 570 °C) over 40 and 60 minutes. In the rheocasting process, the material was melted at 660 °C and slowly cooled down to the processing temperature (595 °C) and then mechanically stirred. The mechanical stirring times varied from 0 (without stirring), 1, 2, 4 and 8 minutes. Cooling was performed by immersion in water (25 °C) in both processes. The samples were analyzed by optical and electronic microscopy to evaluate the microstructure, as well as thermally analyzed. The results showed that the SIMA process reach a superior shape factor, in addition to a coarser and homogeneous morphology than rheocasting

DIFUSÃO DE MATERIAL INFORMATIVO SOBRE O DESCARTE DE RESÍDUOS RADIOLÓGICOS ENTRE ACADÊMICOS DE ODONTOLOGIA E CIRURGIÕES-DENTISTAS DA REGIÃO SUL DO BRASIL

The radiologic material used in dental offices products environmental hazard if not disposedproperly, because the silver, present in chemical solutions used during the development process, isconsidered toxic to humans. The management of Health Services is the process to minimizing theadverse effects caused by toxic waste, reducing the environmental impact. The healthprofessionals knowledge about the disposal process is very important, in order to developingawareness in the academic environment. This study aims to disseminating information on theWaste Management of Health Services among dental students and dentists. In this sense, it wasdeveloped posters and leaflets about the environmental impact caused by the incorrect radiological waste disposal and waste management of Health Services, and distributed in theFederal University of Santa Catarina (UFSC) Dentistry University and Dental Offices and in the citiesof Florianópolis, SC. The leaflets were distributed in one hundred offices, and six posters weredistributed in community colleges. Orientation programs are necessary to promote professionaleducation and awareness about the appropriate approach to waste disposal, as well as theenvironmental impact caused by its breach.O material de radiologia utilizado em consultórios odontológicos produz risco ambiental quando não descartado de forma correta, pois a prata, presente em soluções químicas utilizadas durante o processo de revelação, é considerado tóxico para o ser humano. O gerenciamento dos Serviços de Saúde é o processo utilizado para minimizar os efeitos adversos causados pelo resíduos tóxicos, diminuindo o impacto ambiental. É importante que os profissionais da saúde conheçam o processo de descarte, de forma que essa conscientização deve ocorrer ainda no meio acadêmico. O presente estudo tem como objetivo difundir informações sobre o Gerenciamento de Resíduos de Serviços de Saúde entre os acadêmicos de Odontologia e cirurgiões-dentistas. Foram confeccionados cartazes e panfletos sobre o impacto ambiental causado pelo descarte incorreto dos resíduos radiológicos e o gerenciamento dos Resíduos de Serviços de Saúde, e distribuídos nas Faculdades de Odontologia da Universidade Federal de Santa Catarina (UFSC), e nos Consultórios Odontológicos das cidades de Florianópolis, SC. Os panfletos foram distribuídos em cem consultórios, e seis cartazes foram distribuídos nos Institutos de Ensino Superior. Programas de orientação são necessários para conscientizar os profissionais sobre a conduta adequada para o descarte de resíduos, assim como o impacto ambiental causado pelo não cumprimento da mesma.