1,593 research outputs found
Quality of Life After Bilateral Adrenalectomy in MEN 2
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
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
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)
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
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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