37 research outputs found

    Cardio-respiratory development in bird embryos: new insights from a venerable animal model

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    Post-hatching development of mitochondrial function, organ mass and metabolic rate in two ectotherms, the American alligator (Alligator mississippiensis) and the common snapping turtle (Chelydra serpentina)

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    The ontogeny of endothermy in birds is associated with disproportionate growth of thermogenic organs and increased mitochondrial oxidative capacity. However, no similar study has been made of the development of these traits in ectotherms. For comparison, we therefore investigated the metabolism, growth and muscle mitochondrial function in hatchlings of a turtle and a crocodilian, two ectotherms that never develop endothermy. Metabolic rate did not increase substantially in either species by 30 days post-hatching. Yolk-free body mass and heart mass did not change through 30 days in alligators and heart mass was a constant proportion of body mass, even after 1 year. Yolk-free body mass and liver mass grew 36% and 27%, respectively, in turtles during the first 30 days post-hatch. The mass-specific oxidative phosphorylation capacity of mitochondria, assessed using permeabilized muscle fibers, increased by a non-significant 47% in alligator thigh and a non-significant 50% in turtle thigh over 30 days, but did not increase in the heart. This developmental trajectory of mitochondrial function is slower and shallower than that previously observed in ducks, which demonstrate a 90% increase in mass-specific oxidative phosphorylation capacity in thigh muscles over just a few days, a 60% increase in mass-specific oxidative phosphorylation capacity of the heart over a few days, and disproportionate growth of the heart and other organs. Our data thus support the hypothesis that these developmental changes in ducks represent mechanistic drivers for attaining endothermy

    An ultrastructural study of adenoid cystic carcinoma of the human salivary gland

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    Synthesis and characterization of arrested precipitation assembled Cu2Se thin films

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    Nanostructured thin films of copper selenide (Cu2Se) deposited by arrested precipitation technique (APT) with controlled release of ions at suitable pH=10.5. The deposited Cu2Se films were characterized for optical, structural, and morphological properties. Optical absorption study indicates that the band gap energy (2.26 eV) of material and shows visible radiation absorption. XRD shoe that APT is a favorable technique for the synthesis of pure nanocrystalline Cu2Se thin films with monoclinic crystal structure. An electrochemical impedance spectroscopy analysis confirms the charge transfer resistance.  X-ray photoelectron spectroscopy reveals stoichiometry at valance state of Cu2Se

    Synthesis and characterization of arrested precipitation assembled Cu2Se thin films

    No full text
    Nanostructured thin films of copper selenide (Cu2Se) deposited by arrested precipitation technique (APT) with controlled release of ions at suitable pH=10.5. The deposited Cu2Se films were characterized for optical, structural, and morphological properties. Optical absorption study indicates that the band gap energy (2.26 eV) of material and shows visible radiation absorption. XRD shoe that APT is a favorable technique for the synthesis of pure nanocrystalline Cu2Se thin films with monoclinic crystal structure. An electrochemical impedance spectroscopy analysis confirms the charge transfer resistance.  X-ray photoelectron spectroscopy reveals stoichiometry at valance state of Cu2Se
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