19,355 research outputs found
Recreational Boating in Virginia: a preliminary analysis
Increasingly, recreational boating and its supporting industries are being affected by governmental policy and regulatory and allocation decisions. Clearly, those charged with making these decisions cannot understand the impacts of their decisions on related business, individuals, and their livelihoods without possessing some knowledge of the general linkages between boating and local economies. This initial estimate of the economic impacts of boating in Virginia is a first step in that direction. Hopefully, a better knowledge of the nature, recent growth and present magnitude of boating in the Commonwealth will insure that decisions made which influence its existence will be\u27based on the best information possible
Urinary liver fatty acid-binding protein: another novel biomarker of acute kidney injury
Liver fatty acid-binding protein (L-FABP) binds selectively to intracellular free unsaturated fatty acids and lipid peroxidation products during hypoxic tissue injury. Urinary L-FABP is a potential biomarker for the detection and assessment of acute kidney injury (AKI). Ferguson et al. have demonstrated in a cross-sectional study that urinary L-FABP is an excellent biomarker of AKI and may be useful in predicting dialysis-free survival. This study did not assess utility for early diagnosis of AKI
A non-apoptotic role for caspase-9 in muscle differentiation
Caspases, a family of cysteine proteases most often investigated for their roles in apoptosis, have also been demonstrated to have functions that are vital for the efficient execution of cell differentiation. One such role that has been described is the requirement of caspase-3 for the differentiation of skeletal myoblasts into myotubes but, as yet, the mechanism leading to caspase-3 activation in this case remains elusive. Here, we demonstrate that caspase-9, an initiator caspase in the mitochondrial death pathway, is responsible for the activation of caspase-3 in differentiating C2C12 cells. Reduction of caspase-9 levels, using an shRNA construct, prevented caspase-3 activation and inhibited myoblast fusion. Myosin-heavy-chain expression, which accompanies myoblastic differentiation, was not caspase-dependent. Overexpression of Bcl-xL, a protein that inhibits caspase-9 activation, had the same effect on muscle differentiation as knockdown of caspase-9. These data suggest that the mitochondrial pathway is required for differentiation; however, the release of cytochrome c or Smac (Diablo) could not be detected, raising the possibility of a novel mechanism of caspase-9 activation during muscle differentiation.</jats:p
The Effects of C-terminal Modifications on the Opioid Activity of [N-BenzylTyr1]Dynorphin A-(1-11) Analogs
Structural modifications affecting the efficacy of analogs of the endogenous opioid peptide dynorphin (Dyn) A have focused on the N-terminal “message” sequence, based on the “messageaddress” concept. To test the hypothesis that changes in the C-terminal “address” domain could affect efficacy, modified amino acids and cyclic constraints were incorporated into this region of the partial agonist [N-benzylTyr1]Dyn A-(1-11). Modifications in the C-terminal domain of [NbenzylTyr1] Dyn A-(1-11)NH2 resulted in increased kappa opioid receptor (KOR) affinity for all of the linear analogs, but did not affect the efficacy of these peptides at KOR. Cyclization between positions 5 and 8 yielded [N-benzylTyr1,cyclo(D-Asp5,Dap8)]Dyn A-(1-11)NH2 (13) (Patkar et al. J. Med. Chem. 2005, 48, 4500-4503) with high selectivity for KOR. In contrast to the linear peptides, this peptide exhibits negligible efficacy in the AC assay and is a KOR antagonist. These data are consistent with our hypothesis that appropriate modifications in the “address” domain of Dyn A analogs may affect efficacy
The discovery and dynamical evolution of an object at the outer edge of Saturn's A ring
This work was supported by the Science and Technology Facilities Council (Grant No. ST/F007566/1) and we are grateful to them for financial assistance. C.D.M. is also grateful to the Leverhulme Trust for the award of a Research Fellowshippublisher PDF not permitted, withdraw
Coastal vulnerability of a pinned, soft-cliff coastline. Part I, assessing the natural sensitivity to wave climate
The impact of future sea-level rise on coastal erosion as a result of a changing climate has been studied in detail over the past decade. The potential impact of a changing wave climate on erosion rates, however, is not typically considered. We explore the effect of changing wave climates on a pinned, soft-cliff, sandy coastline, using as an example the Holderness coast of East Yorkshire, UK.
The initial phase of the study concentrates on calibrating a numerical model to recently measured erosion rates for the Holderness coast using an ensemble of geomorphological and shoreface parameters under an observed offshore wave climate. In the main phase of the study, wave climate data are perturbed gradually to assess their impact on coastal morphology. Forward-modelled simulations constrain the nature of the morphological response of the coast to changes in wave climate over the next century. Results indicate that changes to erosion rates over the next century will be spatially and temporally heterogeneous, with a variability of up to ±25% in the erosion rate relative to projections under constant wave climate. The heterogeneity results from the current coastal morphology and the sediment transport dynamics consequent on differing wave climate regimes
Inverse characterization of plates using zero group velocity Lamb modes
AbstractIn the presented work, the characterization of plates using zero group velocity Lamb modes is discussed. First, analytical expressions are shown for the determination of the k–ω location of the zero group velocity Lamb modes as a function of the Poisson’s ratio. The analytical expressions are solved numerically and an inverse problem is formulated to determine the unknown wave velocities in plates of known thickness. The analysis is applied to determine the elastic properties of tungsten and aluminum plates based on the experimentally measured frequency spectra
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