62 research outputs found

    Study of Uncertainties of Predicting Space Shuttle Thermal Environment

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    Quantitative estimates of the uncertainty in predicting aerodynamic heating rates for a fully reusable space shuttle system are developed and the impact of these uncertainties on Thermal Protection System (TPS) weight are discussed. The study approach consisted of statistical evaluations of the scatter of heating data on shuttle configurations about state-of-the-art heating prediction methods to define the uncertainty in these heating predictions. The uncertainties were then applied as heating rate increments to the nominal predicted heating rate to define the uncertainty in TPS weight. Separate evaluations were made for the booster and orbiter, for trajectories which included boost through reentry and touchdown. For purposes of analysis, the vehicle configuration is divided into areas in which a given prediction method is expected to apply, and separate uncertainty factors and corresponding uncertainty in TPS weight derived for each area

    Completion of BAX recruitment correlates with mitochondrial fission during apoptosis

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    BAX, a member of the BCL2 gene family, controls the committed step of the intrinsic apoptotic program. Mitochondrial fragmentation is a commonly observed feature of apoptosis, which occurs through the process of mitochondrial fission. BAX has consistently been associated with mitochondrial fission, yet how BAX participates in the process of mitochondrial fragmentation during apoptosis remains to be tested. Time-lapse imaging of BAX recruitment and mitochondrial fragmentation demonstrates that rapid mitochondrial fragmentation during apoptosis occurs after the complete recruitment of BAX to the mitochondrial outer membrane (MOM). The requirement of a fully functioning BAX protein for the fission process was demonstrated further in BAX/BAK-deficient HCT116 cells expressing a P168A mutant of BAX. The mutant performed fusion to restore the mitochondrial network. but was not demonstrably recruited to the MOM after apoptosis induction. Under these conditions, mitochondrial fragmentation was blocked. Additionally, we show that loss of the fission protein, dynamin-like protein 1 (DRP1), does not temporally affect the initiation time or rate of BAX recruitment, but does reduce the final level of BAX recruited to the MOM during the late phase of BAX recruitment. These correlative observations suggest a model where late-stage BAX oligomers play a functional part of the mitochondrial fragmentation machinery in apoptotic cells

    Clinical pharmacology of cancer therapies in older adults

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    This abbreviated review outlines the physiologic changes associated with aging, and examines how these changes may affect the pharmacokinetics and pharmacodynamics of anticancer therapies. We also provide an overview of studies that have been conducted evaluating the pharmacology of anticancer therapies in older adults, and issue a call for further research

    Risk of chronic kidney disease after cancer nephrectomy.

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    The incidence of early stage renal cell carcinoma (RCC) is increasing and observational studies have shown equivalent oncological outcomes of partial versus radical nephrectomy for stage I tumours. Population studies suggest that compared with radical nephrectomy, partial nephrectomy is associated with decreased mortality and a lower rate of postoperative decline in kidney function. However, rates of chronic kidney disease (CKD) in patients who have undergone nephrectomy might be higher than in the general population. The risks of new-onset or accelerated CKD and worsened survival after nephrectomy might be linked, as kidney insufficiency is a risk factor for cardiovascular disease and mortality. Nephron-sparing approaches have, therefore, been proposed as the standard of care for patients with type 1a tumours and as a viable option for those with type 1b tumours. However, prospective data on the incidence of de novo and accelerated CKD after cancer nephrectomy is lacking, and the only randomized trial to date was closed prematurely. Intrinsic abnormalities in non-neoplastic kidney parenchyma and comorbid conditions (including diabetes mellitus and hypertension) might increase the risks of CKD and RCC. More research is needed to better understand the risk of CKD post-nephrectomy, to develop and validate predictive scores for risk-stratification, and to optimize patient management

    Sensitivity of Boundary-Layer Transition to Surface Irregularities for Space Shuttle Applications

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    Increased susceptibility and intrinsic apoptotic signaling in neurons by induced HDAC3 expression

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    Inhibition or targeted deletion of histone deacetylase 3 (HDAC3) is neuroprotective in a variety neurodegenerative conditions, including retinal ganglion cells (RGCs) after acute optic nerve damage. Consistent with this, induced HDAC3 expression in cultured cells shows selective toxicity to neurons. Despite an established role for HDAC3 in neuronal pathology, little is known regarding the mechanism of this pathology
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