The world haunted by Covid-19

In this time of confinement due to COVID-19 pandemic some reflections have been made e it has never been as clear as people can benefit from science. From the simple gesture of washing your hands like many others used during the quarantine, they have been identified by previous studies. In this way, we reinforce the need to maintain investments in the science.In this time of confinement due to COVID-19 pandemic some reflections have been made e it has never been as clear as people can benefit from science. From the simple gesture of washing your hands like many others used during the quarantine, they have been identified by previous studies. In this way, we reinforce the need to maintain investments in the science.In this time of confinement due to COVID-19 pandemic some reflections have been made e it has never been as clear as people can benefit from science. From the simple gesture of washing your hands like many others used during the quarantine, they have been identified by previous studies. In this way, we reinforce the need to maintain investments in the science

Comparison of Microstructures and Mechanical Properties for Solid Cobalt-Base Alloy Components and Biomedical Implant Prototypes Fabricated by Electron Beam Melting

The microstructures and mechanical behavior of simple, as-fabricated, solid geometries (with a density of 8.4 g/cm3), as-fabricated and fabricated and annealed femoral (knee) prototypes all produced by additive manufacturing (AM) using electron beam melting (EBM) of Co-26Cr-6Mo-0.2C powder are examined and compared in this study. Microstructures and microstructural issues are examined by optical metallography, SEM, TEM, EDS, and XRD while mechanical properties included selective specimen tensile testing and Vickers microindentation (HV) and Rockwell C-scale (HRC) hardness measurements. Orthogonal (X-Y) melt scanning of the electron beam during AM produced unique, orthogonal and related Cr23C6 carbide (precipitate) cellular arrays with dimensions of ~2μm in the build plane perpendicular to the build direction, while connected carbide columns were formed in the vertical plane, parallel to the build direction.Mechanical Engineerin

Microstructure Architecture Development in Metals and Alloys By Additive Manufacturing Using Electron Beam Melting

The concept of materials with controlled microstructural architecture (MCMA) to develop and fabricate structural materials with novel and possibly superior properties and performance characteristics is a new paradigm or paradigm extension for materials science and engineering. In the conventional materials science and engineering paradigm, structure (microstructure), properties, processing, and performance features are linked in the development of desirable materials properties and performance through processing methodologies which manipulate microstructures. For many metal or alloy systems, thermomechanical treatment combining controlled amounts of plastic deformation with heat treatment or aging cycles can achieve improved mechanical properties beyond those attainable by conventional processing alone (such as rolling or forging for example) through controlled microstructure development. In this paper we illustrate a new concept involving the fabrication of microstructural architectures by the process development and selective manipulation of these microstructures ideally defining material design space. This allows for the additional or independent manipulation of material properties by additive manufacturing (AM) using electron beam melting (EBM). Specifically we demonstrate the novel development of a carbide (M23C6) architecture in the AM of a Co-base alloy and an oxide (Cu2O) precipitate-dislocation architecture in the AM of an oxygen-containing Cu. While more conventional processing can produce various precipitate microstructures in these materials, EBM produces spatial arrays of precipitate columns or columnar-like features often oriented in the build direction. These microstructural architectures are observed by optical microscopy and scanning and transmission electron microscopy. Prospects for EBM architecture development in precipitation-hardenable Al alloys is also discussed. In the EBM build process using precursor powders, the electron beam parameters (including beam focus, scan speed and sequencing) produce localized, requisite thermodynamic regimes which create or organize the precipitate-related spatial arrays. This feature demonstrates the utility of AM not only in the fabrication of complex components, but also prospects for selective property design using CAD for MCMA development: a new or extended processing-microstructure-property-performance paradigm for materials science and engineering in advanced manufacturing involving solid free-form fabrication (SFF).Mechanical Engineerin

Caracterização da produção agroecológica do sul do Rio Grande do Sul e sua relação com a mecanização agrícola.

A agricultura agroecológica tem-se destacado como uma das alternativas de renda para os pequenos agricultores devido à crescente busca por parte da população por alimentação mais saudável. No Rio Grande do Sul, a Associação Regional de Produtores Agroecológicos da Região Sul (Arpasul), constituída por 48 famílias, é representativa do processo de produção e de comercialização de produtos agroecológicos, servindo como referencial para o presente estudo. O objetivo principal deste trabalho foi o levantamento das necessidades dos produtores agroecológicos em relação à mecanização agrícola. As informações obtidas foram baseadas no sistema de produção utilizado, sendo caracterizados aspectos referentes à propriedade, às operações agrícolas e às necessidades específicas de máquinas e implementos. Por meio deste estudo, foi evidenciada a carência no atendimento das demandas específicas, na área de máquinas agrícolas para esse segmento, podendo servir como referencial para o desenvolvimento de novas máquinas e/ou aperfeiçoamento das existentes. A semeadora de milho e feijão foi a máquina que a maioria dos agricultores pesquisados indicou como sua maior necessidade

Retinoic acid and cAMP inhibit rat hepatocellular carcinoma cell proliferation and enhance cell differentiation

Hepatocellular carcinoma (HCC) is the third highest cause of cancer death worldwide. In general, the disease is diagnosed at an advanced stage when potentially curative therapies are no longer feasible. For this reason, it is very important to develop new therapeutic approaches. Retinoic acid (RA) is a natural derivative of vitamin A that regulates important biological processes including cell proliferation and differentiation. In vitro studies have shown that RA is effective in inhibiting growth of HCC cells; however, responsiveness to treatment varies among different HCC cell lines. The objective of the present study was to determine if the combined use of RA (0.1 µM) and cAMP (1 mM), an important second messenger, improves the responsiveness of HCC cells to RA treatment. We evaluated the proliferative behavior of an HCC cell line (HTC) and the expression profile of genes related to cancer signaling pathway (ERK and GSK-3β) and liver differentiation (E-cadherin, connexin 26 (Cx26), and Cx32). RA and cAMP were effective in inhibiting the proliferation of HTC cells independently of combined use. However, when a mixture of RA and cAMP was used, the signals concerning the degree of cell differentiation were increased. As demonstrated by Western blot, the treatment increased E-cadherin, Cx26, Cx32 and Ser9-GSK-3β (inactive form) expression while the expression of Cx43, Tyr216-GSK-3β (active form) and phosphorylated ERK decreased. Furthermore, telomerase activity was inhibited along treatment. Taken together, the results showed that the combined use of RA and cAMP is more effective in inducing differentiation of HTC cells

Efecto de la carga animal y el tipo de piso sobre el rendimiento, la temperatura de la piel y leucograma en la cría de cerdos

Objective. The aim of this study was to evaluate the performance, thermoregulatory characteristics and the leucogram of growing finishing pigs reared in different stocking rates kept on compact floor pens or with shallow pool pens. Material and methods. Thirty-six pigs were used in two steps (total of 72 animals were used). In the first step it was analysed performance pig (daily feed intake, weight gain and feed: gain ratio) and backfat thickness (P2). In the second step, the same analyzes were repeated, in addition, analysis of leucogram and skin temperature was performad in P2 and anal region, at the end of growing and finishing phase. Results. It was evaluated for differences between treatments and stocking. It was not found effect of floor type on growing phase, but the use of shallow pool had a negative effect on the gain and feed: gain ration in the finishing phase. Increasing linear effect on backfat thickness as the stocking rate was reduced, as well as lower surface temperature in the anal region on treatment with shallow pool in the finishing phase. No effect of treatments and type of floor on leucogram pigs. Allowing more space/animal decreased backfat thickness. The use of shallow pool affected negatively the performance in the finishing phase. Conclusions. The shallow pool uses impair the finishing pig performance, despite improving thermolysis, with no effect observed on cell immune response.Objetivo. El objetivo de este estudio fue evaluar el rendimiento, las características de termorregulación, y el leucograma de cerdos de engorde, criados en diferentes densidad mantenidos en corrales de piso compactos o en piscinas de poca profundidad. Material y métodos. Treinta y seis cerdos se utilizaron en dos etapas (un total de 72 animalles utilizados). En el primer paso, se analizaron las características zootécnicas (consumo diario de alimento, ganancia de peso y alimento: ganancia) y el espesor de grasa dorsal (P2). En el segundo paso, los mismos análisis se repitieron, además, el análisis de leucograma y temperatura de la piel se realizó en P2 y la región anal, al final del crecimiento y del acabado de fase. Resultados. Se evaluaron las diferencias entre los tratamientos y media. No se encontró efecto del tipo de suelo en fase de crecimiento, pero el uso de la piscina de poca profundidad tuvo un efecto negativo sobre la ganancia y la alimentación: ración de ganancia en la fase de acabado. El aumento de efecto lineal de espesor de grasa dorsal como la tasa media se redujo, así como una menor temperatura de la superficie en la región anal en el tratamiento con piscina de poca profundidad en la fase de acabado. No hubo efecto de los tratamientos y tipo de suelo sobre el Leucograma de los cerdos. Permitiendo más espacio/animal disminuyó el espesor de grasa dorsal. El uso de la piscina de poca profundidad afectó negativamente al rendimiento en la fase de acabado. Conclusiones. El uso de la piscina de poca profundidad afectó el rendimiento de los cerdos de acabado, a pesar de la mejora de termólisis, sin efecto visible en la respuesta inmune celular