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Electronic structure and phase equilibria in ternary substitutional alloys
A reliable, consistent scheme to study phase equilibria in ternary substitutional alloys based on the tight-binding approximation is presented. With electronic parameters from linear muffin-tin orbital calculations, the computed density of states and band structures compare well with those from more accurate {ital ab}{ital initio} calculations. Disordered alloys are studied within the tight-binding coherent-potential approximation extended to alloys; energetics of ordered systems are obtained through effective pair interactions computed with the general perturbation method; and partially ordered alloys are studied with a novel simplification of the molecular coherent-potential approximation combined with the general perturbation method. The formalism is applied to bcc-based Zr-Ru-Pd alloys which are promising candidates for medical implant devices. Using energetics obtained from the above scheme, we apply the cluster- variation method to study phase equilibria for particular pseudo- binary alloys and show that results are consistent with observed behavior of electronic specific heat coefficient with composition for Zr{sub 0.5}(Ru, Pd){sub 0.5}
Moving the pulsed heating technique beyond monolithic specimens: Experiments with coated wires
Efficacy of menthol as an anesthetic for tambaqui (Colossoma macropomum, Characiformes: Characidae)
Anesthetics are important in fish culture to reduce handling stress and mortality. The objective of this work is to investigate menthol as an anesthetic for tambaqui. In the first series of tests, fish were exposed to various concentrations of menthol to evaluate induction time and stress responses. The second series examined the effect of exposure period to menthol at 150 mg/L on recovery time. The third assessed the best dosage for juveniles in larger tambaqui. The best concentration for surgical anesthesia is 150 mg/L. At this concentration the induction time is short, but their recovery time is significantly longer than that for lower concentrations. For biometry procedures, the best concentration is 100 mg/L. At this concentration the induction time is prolonged, but the recovery time is within the desired period. Recovery time for fish exposed to 150 mg/L is equal for 10, 20 or 30 minutes of exposure. The results confirmed that menthol is an adequate anesthetic for tambaqui.Os anestésicos são importantes na piscicultura para reduzir o estresse e a mortalidade no manejo. Este trabalho tem como objetivo determinar a eficácia do mentol para tambaqui durante o manejo. Na primeira série de testes, foi examinado o efeito da concentração de anestésico sobre indução à anestesia e o estresse de tambaqui. Na segunda série de testes, foi avaliada a recuperação dos peixes após a exposição a uma concentração de 150 mg/L de mentol por diferentes tempos. Na terceira série, foi avaliada se a melhor concentração encontrada para juvenil (150 mg/L) também era adequada para peixes maiores. A melhor concentração para uma anestesia cirúrgica foi 150 mg/L, pois o tempo de indução é rápido, porém a recuperação é significativamente mais demorada do que para as menores concentrações testadas. Para uma anestesia, com finalidade de biometria, a melhor concentração foi 100 mg/L. Nesta concentração o tempo de indução à anestesia é prolongado, porém o tempo de recuperação está dentro da faixa considerada adequada. O tempo de recuperação do tambaqui quando exposto a 150 mg/L é significativamente igual para 10, 20 e 30 minutos de anestesia. Os resultados obtidos mostram que o mentol é um anestésico eficiente para o tambaqui
Cell cycle regulation in hematopoietic stem cells
Hematopoietic stem cells (HSCs) give rise to all lineages of blood cells. Because HSCs must persist for a lifetime, the balance between their proliferation and quiescence is carefully regulated to ensure blood homeostasis while limiting cellular damage. Cell cycle regulation therefore plays a critical role in controlling HSC function during both fetal life and in the adult. The cell cycle activity of HSCs is carefully modulated by a complex interplay between cell-intrinsic mechanisms and cell-extrinsic factors produced by the microenvironment. This fine-tuned regulatory network may become altered with age, leading to aberrant HSC cell cycle regulation, degraded HSC function, and hematological malignancy
Crustáceos decápodos associados às cordas de cultivo do mexilhão Perna perna (Linnaeus, 1758) (Mollusca, Bivalvia, Mytilidae) na Enseada da Armação do Itapocoroy, Penha - SC
Activity-Composition Relations in Platinum-Chromium and Platinum-Vanadium Alloys at 1500oC
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