Efeito do tratamento superficial com laser na microestrutura e na propaga??o de trincas por fadiga em uma liga de alum?nio do tipo AA6013-T4.

Programa de P?s-Gradua??o em Engenharia de Materiais. Departamento de Engenharia Metal?rgica, Escola de Minas, Universidade Federal de Ouro Preto.Um dos maiores desafios da ind?stria aeron?utica ? desenvolver m?todos para aumentar a vida ?til de seus componentes. A filosofia de toler?ncia de danos deve ser considerada ao se projetar toda estrutura da aeronave. Assim an?lises da taxa de propaga??o de trincas por fadiga (PTF) devem ser realizadas durante o projeto dos componentes aeron?uticos, pois a maior parte dos desastres que ocorrem neste segmento ? causada por falhas por fadiga. Uma t?cnica promissora para aumentar a vida ?til do material que comp?e a parte estrutural da aeronave, ou seja, melhorar seu comportamento em fadiga, ? o tratamento superficial localizado com laser que produz um campo de tens?o residual compressiva na ponta da trinca, retardando o seu crescimento. Neste trabalho foi avaliada a influ?ncia deste tratamento na microestrutura e na taxa de PTF na regi?o II da curva sigmoidal da/dN x ?K de uma liga de alum?nio aeron?utico do tipo AA6013-T4. O estudo buscou escolher os par?metros mais adequados como aporte t?rmico e posi??es de tra?ar as linhas de laser, a serem utilizados na pr?tica sem prejudicar as propriedades mec?nicas da liga, baseado em trabalhos pr?vios que est?o abordados ao longo do texto e tamb?m em an?lises realizadas durante o doutorado. Assim, ap?s a escolha das vari?veis de opera??o, o tratamento foi realizado utilizando um laser de Yb:fibra em chapas de 1,3mm de espessura e aplicando trilhas de duas formas diferentes: somente em uma superf?cie lateral e em ambas superf?cies laterais de corpos de prova do tipo C(T). Utilizou-se pot?ncia de 200W e velocidade de aplica??o de 2mm/s e 20mm/s. Al?m disso, o feixe foi desfocado para se obter um di?metro de 2mm, com objetivo de evitar a fus?o da pe?a. No metal de base foram encontrados zonas de Guinier-Preston, dispers?ides e constituintes grosseiros. Estes mesmos componentes e tamb?m precipitados do tipo ?? e Q? foram encontrados no material tratado. Essas varia??es microestruturais devido ao ciclo t?rmico, juntamente com a presen?a de tens?o residual compressiva pr?xima ? regi?o aquecida melhoraram o comportamento em fadiga da liga em estudo. O retardamento da taxa PTF foi maior nos corpos de prova tratados com maior aporte t?rmico e duas trilhas aplicadas nas duas superf?cies laterais.One of the biggest challenge on aerospace industry is to develop methods to increase the long life of its components. The damage tolerance philosophy should be considered when designing any aircraft structure. Thus fatigue crack growth (FCG) analyzes must be performed during the design of the aeronautical components because the most of the disasters that occur in this segment are caused by fatigue failures. A promising technique to increase the material life, i.e. improving its fatigue resistance, is the localized laser surface treatment that produces a compressive residual stress field at the crack tip, slowing its growth. This work analyzed the influence of laser surface treatment on microstructure and fatigue crack growth (FCG) rate on region II of the sigmoidal da/dN x ?K curve of an aerospace grade AA6013-T4 aluminum alloy sheet with 1.3mm thickness. Previous studies had been taken into account before choosing the operational parameters. Aiming to improve the FCG resistance without damaging the mechanical properties of the alloy, a defocused Yb:fiber laser beam generated a laser spot diameter of 2mm, using 200W power and a laser speed of 2mm/s and 20mm/s. Two laser lines over C(T) fatigue specimens were applied in two different forms: on only one and on both lateral specimen surfaces. Guinier-Preston zones, dispersoids and coarse constituent particles were found on the base material. The same precipitates and also ? and Q` precipitates were found on the heat treated material. These microstructural variations due to the laser thermal cycle, together with the presence of induced compressive residual stresses, improved the fatigue behavior of the material. The FCG retardation was greater when two laser lines were applied on both lateral surfaces of the specimen

Soft Skills como Componente Fundamental na Educa??o de T?cnicos em Enfermagem: Abordagens Pedag?gicas Inovadoras

O cultivo das soft skills na trajet?ria de um t?cnico em enfermagem ? um componente essencial para garantir uma carreira duradoura e bem-sucedida. A promo??o dessas habilidades durante o per?odo de forma??o desempenha um papel fundamental no processo educacional, exigindo que os alunos mergulhem profundamente no desenvolvimento dessas compet?ncias. Essa imers?o n?o apenas enriquece a aprendizagem, mas tamb?m proporciona experi?ncias valiosas que se estendem al?m do ?mbito profissional, influenciando positivamente a vida pessoal dos estudantes. Nesse contexto, este trabalho consiste em uma proposta de interven??o pedag?gica sobre a implementa??o de ferramentas para o desenvolvimento de soft skills no curso T?cnico em Enfermagem. A metodologia para o desenvolvimento deste trabalho consiste em uma abordagem descritiva, com aplica??o direta durante o per?odo de forma??o. Desse modo, espera-se que a referida interven??o pedag?gica contribua no desenvolvimento de compet?ncias e habilidades associadas ?s compet?ncias t?cnicas dos alunos do Curso T?cnico em Enfermagem.n?o h

Silagens de capim-elefante aditivadas com coprodutos do biodiesel

O presente trabalho foi realizado com apoio da Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior ? Brasil (CAPES) ? C?digo de Financiamento 001.Objetivou-se avaliar os efeitos da torta de maca?ba e farelo de crambe, oriundos da cadeia produtiva do biodiesel, em diferentes n?veis de inclus?o na ensilagem de capim-elefante. O delineamento experimental foi o inteiramente casualizado, com quatro repeti??es. O material foi ensilado em silos experimentais elaborados com tubos de PVC com tampas providas de v?lvula tipo Bunsen, compactou-se o material obtendo-se massa espec?fica de 600 kg/m3. Foi analisado teores de ?cidos org?nicos, popula??o microbiana, composi??o qu?mico-bromatol?gica e as perdas geradas durante o processo fermentativo. Os tratamentos foram dispostos em esquema fatorial 3 x 6, sendo tr?s n?veis de inclus?o de cada coproduto do biodiesel (0; 10 e 20%) e seis tempos de abertura dos silos (1; 5; 10; 20; 40 e 60 dias ap?s a ensilagem). A torta de maca?ba foi eficiente como aditivo absorvente de umidade nas silagens de capim-elefante, no qual proporcionou eleva??o dos teores de mat?ria seca, al?m da melhoria no processo fermentativo, que favoreceu o desenvolvimento de microrganismos desej?veis, e, reduziu a popula??o de fungos provavelmente por meio da a??o antif?ngica propiciada pela adequada produ??o de ?cido ac?tico, o que favoreceu baixa produ??o de etanol. Houve redu??o dos teores de ?cido but?rico, aumento de ?cido l?tico, e, consequente redu??o dos valores de pH, que foram satisfat?rios para a conserva??o do material ensilado. N?veis crescentes da torta de maca?ba reduziram a prote?lise no material ensilado, o que resultou em menores concentra??es de nitrog?nio amoniacal. Os teores de fibras foram reduzidos com a adi??o da torta de maca?ba, os teores de prote?na elevaram-se, por?m, n?o foram t?o expressivos, n?o houve contribui??o da torta de maca?ba sobre os carboidratos sol?veis. Os teores de extrato et?reo aumentaram com os n?veis crescentes da torta de maca?ba, o que deve-se atentar para que o uso na alimenta??o animal n?o limite o consumo de mat?ria seca e reduza a digestibilidade da fibra. Nas silagens de capim-elefante com 20% da torta de maca?ba, devem ser misturados a outros alimentos com concentra??o de extrato et?reo menor, as perdas por gases e efluentes foram reduzidas e a recupera??o de mat?ria seca nas silagens de capim-elefante foi aumentada com a inclus?o da torta de maca?ba, sendo que a adi??o de 20% proporcionou melhores resultados. O farelo de crambe adicionado na ensilagem de capim-elefante foi eficiente na melhoria do processo fermentativo atrav?s da eleva??o dos teores de mat?ria seca, da contribui??o para o desenvolvimento de microrganismos ben?ficos em detrimento dos indesej?veis, da predomin?ncia da fermenta??o l?tica com consequente redu??o do pH, al?m do incremento do valor nutricional, principalmente pela eleva??o do teor proteico e redu??o dos teores de fibras, contudo, o farelo de crambe favoreceu a eleva??o dos teores de nitrog?nio amoniacal. As perdas por gases e efluentes foram reduzidas e a recupera??o de mat?ria seca nas silagens de capim-elefante foi aumentada com a inclus?o do farelo de crambe. O maior n?vel de inclus?o (20%) do farelo de crambe promoveu as melhores caracter?sticas nas silagens de capim-elefante.Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)Tese (Doutorado) ? Programa de P?s-gradua??o em Biocombust?veis, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2018.The objective of this study was to evaluate the effects of maca?ba cake and crambe bran from the biodiesel production chain on different levels of inclusion in elephant grass silage. The experimental design was completely randomized, with four replications. The material was ensiled in experimental silos made with PVC tubes with caps equipped with a Bunsen type valve, the material was compacted to obtain a specific mass of 600 kg/m3. The content of organic acids, microbial population, chemical-bromatological composition and the losses generated during the fermentation process were analyzed. The treatments were arranged in a 3 x 6 factorial scheme, with three inclusion levels of each biodiesel co-product (0, 10 and 20%) and six silos opening times (1, 5, 10, 20, 40 and 60 days after the silage). The maca?ba cake was efficient as a moisture-absorbing additive in elephant grass silages, in which it increased the dry matter contents, as well as improving the fermentation process, which favored the development of desirable microorganisms, and reduced the fungus population probably through the antifungal action provided by the adequate production of acetic acid, which favored low ethanol production. There was a decrease in butyric acid, increase of lactic acid, and consequent reduction of pH values, which were satisfactory for the conservation of silage. Increasing levels of maca?ba cake reduced the proteolysis in the ensiled material, which resulted in lower concentrations of ammonia nitrogen. The fiber contents were reduced with the addition of the maca?ba cake, the protein levels were elevated, however, they were not as expressive, there was no contribution of the maca?ba cake to the soluble carbohydrates. Ethereal extract contents increased with the increasing levels of maca?ba cake, which should be taken care that the use in animal feed does not limit dry matter consumption and reduce fiber digestibility. In the elephant grass silages with 20% of the maca?ba cake, they should be mixed with to other foods with a lower concentration of ethereal extract, gas and effluent losses were reduced and dry matter recovery in elephant grass silages was increased with the inclusion of maca?ba cake, and the addition of 20% provided better results. The crambe bran added in elephant grass silage was efficient in improving the fermentation process by raising dry matter contents, contributing to the development of beneficial microorganisms to the detriment of undesirable ones, the predominance of lactic fermentation with consequent reduction of pH , in addition to the increase in nutritional value, mainly due to the elevation of protein content and reduction of fiber content, however, the crambe bran favored the elevation of ammoniacal nitrogen contents. Gaseous and effluent losses were reduced and recovery of dry matter in elephant grass silages was increased with the inclusion of crambe bran. The highest level of inclusion (20%) of crambe bran promoted the best characteristics in elephant grass silages

Relationship between power condition, agility, and speed performance among young roller hockey elite players

Purpose. The study was intended to describe the correlations between speed performance (11 m, 22 m, and 33 m) and agility test in skates with determinants of muscular power (squat jump, countermovement jump) in young Portuguese roller hockey athletes involved in a regional selection. Methods. A cross-sectional study was conducted among 10 male roller hockey players with mean (? SD) age of 14.20 (0.57) years, involved in the Portuguese national competition of under-15, making part of the final Oporto district selection of players to participate in inter-regional selections competition. Their mean (? SD) weight, height, body mass index, and sum of the skinfolds were 58.62 (8.78) kg, 165.72 (8.45) cm, 21.26 (1.52) kg/m2, 51.80 (14.91) mm, respectively. Furthermore, it strength was measured with squat jump and countermovement jump; sprinting time at 11 m, 22 m, and 33 m was determined, as well as time in an agility t-test, conducted in roller skating. Spearman correlation coefficients were calculated to test the associations. Results. Significant inverse correlations between vertical jumps, a practical method of power training monitoring, and linear velocity in skating (countermovement jump vs. speed, ?0.78) were found. Despite the increasing complexity of the agility test, a moderate inverse correlation with strength was observed, too (?0.48). Conclusions. Lower limbs explosive strength turned out a strong predictor of skating linear speed and agility among young roller hockey players, providing a simple evaluation tool of important determinants of performance.D915-7373-ED16 | Cesar LeaoN/

Antileukemic, Antioxidant, Anti-Inflammatory and Healing Activities Induced by a Polyphenol-Enriched Fraction Extracted from Leaves of Myrtus communis L.

Natural products have offered a number of exciting approaches in cancer treatment over the years. In this study, we investigated the prophylactic and therapeutic effects of the polyphenol-enriched fraction extracted from Myrtus communis (PEMC) on acute and chronic leukemia. According to the UHPLC-MSn, the fraction is rich in flavonoids. Protective activity of the PEMC was assessed by evaluating the antioxidant, anti-inflammatory, wound healing, and hemolysis potential in a series of in vivo and in vitro assays, while the therapeutic approach consisted of the evaluation of cytotoxic activity of the PEMC against HL60 and K562 leukemia cell lines. Safety of the fraction was also evaluated on a non-cancerous Vero cell line and by an acute toxicity test performed in mice. The PEMC demonstrated a significant anti-inflammatory and healing potential. The activities found at the dose of 100 mg/kg were better than those observed using a reference drug. The PEMC demonstrated a significant antioxidant effect and a specific cytotoxicity towards HL60 (IC50 = 19.87 µM) and K562 (IC50 = 29.64 µM) cell lines being non-toxic to the Vero cell line. No hemolytic activity was observed in vitro and no toxicity effect was found in mice. Thus, the PEMC has a pharmacological potential as both preventive and therapeutic agent. However, further research is necessary to propose its mechanism of action

Dynasore, a Dynamin Inhibitor, Inhibits Trypanosoma cruzi Entry into Peritoneal Macrophages

BACKGROUND: Trypanosoma cruzi is an intracellular parasite that, like some other intracellular pathogens, targets specific proteins of the host cell vesicular transport machinery, leading to a modulation of host cell processes that results in the generation of unique phagosomes. In mammalian cells, several molecules have been identified that selectively regulate the formation of endocytic transport vesicles and the fusion of such vesicles with appropriate acceptor membranes. Among these, the GTPase dynamin plays an important role in clathrin-mediated endocytosis, and it was recently found that dynamin can participate in a phagocytic process. METHODOLOGY/PRINCIPAL FINDINGS: We used a compound called dynasore that has the ability to block the GTPase activity of dynamin. Dynasore acts as a potent inhibitor of endocytic pathways by blocking coated vesicle formation within seconds of its addition. Here, we investigated whether dynamin is involved in the entry process of T. cruzi in phagocytic and non-phagocytic cells by using dynasore. In this aim, peritoneal macrophages and LLC-MK2 cells were treated with increasing concentrations of dynasore before interaction with trypomastigotes, amastigotes or epimastigotes. We observed that, in both cell lines, the parasite internalization was drastically diminished (by greater than 90% in LLC-MK2 cells and 70% in peritoneal macrophages) when we used 100 microM dynasore. The T. cruzi adhesion index, however, was unaffected in either cell line. Analyzing these interactions by scanning electron microscopy and comparing peritoneal macrophages to LLC-MK2 cells revealed differences in the stage at which cell entry was blocked. In LLC-MK2 cells, this blockade is observed earlier than it is in peritoneal macrophages. In LLC-MK2 cells, the parasites were only associated with cellular microvilli, whereas in peritoneal macrophages, trypomastigotes were not completely engulfed by a host cell plasma membrane. CONCLUSIONS/SIGNIFICANCE: Taken together our results demonstrate that dynamin is an essential molecule necessary for cell invasion and specifically parasitophorous vacuole formation by host cells during interaction with Trypanosoma cruzi

Chronic inflammatory polyneuropathy associated with ulcerative colitis: a reported case in literature

AbstractBackground: Peripheral neuropathy is known to be related to inflammatory bowel disease and it is one of the most frequently reported neurologic complications. Various studies have found peripheral nervous system complications, rather than central nervous system involvement, to be predominant. In the literature, there are a few cases of inflammatory polyneuropathy developed in the course of ulcerative colitis : 5 cases of Guillain-Barré syndrome, one case of chronic inflammatory demyelinating polyneuropathy, 10 cases of neuropathy and one case of perineuritis. Case presentation: We describe a case of chronic inflammatory polyneuropathy associated with ulcerative colitis. Conclusion: Peripheral neuropathy is not a common manifestation of IBD, highlighting the need for careful exclusion of other causes of neuropathy when both conditions are encountered in clinical practice. Â