1,579 research outputs found

    Quality of Life After Bilateral Adrenalectomy in MEN 2

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    Pheochromocytoma is a major cause of morbidity and mortality in the multiple endocrine neoplasia type 2 (MEN 2) syndrome. For the physician, surgical treatment seems well justified even though bilateral adrenalectomy will induce iatrogenically complete loss of adrenocortical function. For the patient this treatment may be a cause of medical problems as well as worry. We have evaluated quality of life after bilateral adrenalectomy in 27 MEN 2 patients through a combined oral and written approach. Mortality was low (one of 27), as was serious morbidity. Most patients had adapted well to the postadrenalectomy state. However, fatigue, worry, and noncompliance with daily medication often caused problems

    AFM pulling and the folding of donor-acceptor oligorotaxanes: phenomenology and interpretation

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    The thermodynamic driving force in the self-assembly of the secondary structure of a class of donor-acceptor oligorotaxanes is elucidated by means of molecular dynamics simulations of equilibrium isometric single-molecule force spectroscopy AFM experiments. The oligorotaxanes consist of cyclobis(paraquat-\emph{p}-phenylene) rings threaded onto an oligomer of 1,5-dioxynaphthalenes linked by polyethers. The simulations are performed in a high dielectric medium using MM3 as the force field. The resulting force vs. extension isotherms show a mechanically unstable region in which the molecule unfolds and, for selected extensions, blinks in the force measurements between a high-force and a low-force regime. From the force vs. extension data the molecular potential of mean force is reconstructed using the weighted histogram analysis method and decomposed into energetic and entropic contributions. The simulations indicate that the folding of the oligorotaxanes is energetically favored but entropically penalized, with the energetic contributions overcoming the entropy penalty and effectively driving the self-assembly. In addition, an analogy between the single-molecule folding/unfolding events driven by the AFM tip and the thermodynamic theory of first-order phase transitions is discussed and general conditions, on the molecule and the cantilever, for the emergence of mechanical instabilities and blinks in the force measurements in equilibrium isometric pulling experiments are presented. In particular, it is shown that the mechanical stability properties observed during the extension are intimately related to the fluctuations in the force measurements.Comment: 42 pages, 17 figures, accepted to the Journal of Chemical Physic

    The Distance to the M31 Globular Cluster System

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    The distance to the centroid of the M31 globular cluster system is determined by fitting theoretical isochrones to the observed red-giant branches of fourteen globular clusters in M31. The mean true distance modulus of the M31 globular clusters is found to be 24.47 +/- 0.07 mag. This is consistent with distance modulii for M31 that have been obtained using other distance indicators.Comment: 11 pages, 2 postscript figures, uses aaspp4.sty, to be published in the May 1998 Astronomical Journa

    NEUTRON FLUX DISTRIBUTIONS IN NATURAL URANIUM TUBES (thesis)

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    Measurements were made in the Process Revelopment Pile (PDP) of the distribution of the thermal neutron flux in ten different D/sub 2/O-moderated lattices of natural uranium tubes. Both single and double fuel tubes were used at lattice spacings of 7 and 14 inches. Special corrections were required for epithermal flux shielding by the manganese detector foils. After these corrections were applied, good agreement was obtained between the measured flux distributions and correspending distributions calculated by the P/sub 3/ approximation to transport theory. (auth

    Biologically significant residual persistence of brodifacoum in reptiles following invasive rodent eradication, Galapagos Islands, Ecuador

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    Rat eradication resulted in prolonged presence of the anticoagulant rodenticide brodifacoum in exposed lizards, likely significantly contributing to the deaths of secondarily exposed raptors up to at least 773 days after bait application
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