939 research outputs found
Interaction between nitric oxide signaling and gap junctions: Effects on vascular function
Nitric oxide signaling, through eNOS (or possibly nNOS), and gap junction communication are essential for normal vascular function. While each component controls specific aspects of vascular function, there is substantial evidence for cross-talk between nitric oxide signaling and the gap junction proteins (connexins), and more recently, protein protein association between eNOS and connexins. This review will examine the evidence for interaction between these pathways in normal and diseased arteries, highlight the questions that remain about the mechanisms of their interaction, and explore the possible interaction between nitric oxide signaling and the newly discovered pannexin channels. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics. (C) 2011 Elsevier B.V. All rights reserved
Baryonic contributions to the dilepton spectrum of nucleon-nucleon collisions
We study the production of dileptons in relativistic nucleon-nucleon
collisions. Additionally to the traditional dilepton production channels
(vector meson decays, meson and Delta(1232) Dalitz decays) we included in our
model as new dilepton sources the Dalitz decay of higher unflavored baryon
resonances with spin<=5/2 and mass<=2.25 GeV/c^2. The contributions of these
new channels are estimated using experimental information about the Ngamma
decays of the resonances and have large uncertainties. The obtained dilepton
spectra are compared to the experimental data by the DLS collaboration.
Predictions for the HADES detector (SIS, GSI) are also discussed. In spite of
the large uncertainties of the higher resonance Dalitz decay contributions we
are able to draw the conclusion that these contributions are negligible
compared to the other dilepton sources and do not influence the detectability
of the phi and omega vector meson peaks.Comment: 9 pages, 4 figures, version accepted for publication in Phys. Rev.
Novel Modification of HeartMate 3 Implantation
We have modified the HeartMate 3 (Abbott, Abbott Park, IL) implantation technique to better suit our patient population. This modification optimizes the placement of the HeartMate 3 sewing cuff and allows passage of the suture transmurally from endocardium to epicardium in a “cut then sew” technique. We believe this affords a superior seal and protection from tearing friable myocardium
Fragility of randomized trials supporting cancer drug approvals stratified by approval pathway and review designations
Background: It has been suggested that the results from fragile trials are less likely to translate into benefit in routine clinical practice. Methods: We searched the Food and Drug Administration (FDA) archives to identify drug approvals for solid organ malignancies between 2010 and 2019. We calculated the Fragility Index (FI) supporting each approval, using methods to account for time-to-event. We compared FI and trial and approval characteristics using Mann-Whitney U and Kruskal-Wallis test. Using logistic regression, we examined study characteristics associated with withdrawal of consent or lost to follow-up (WCLFU) exceeding the calculated FI. Results: The median FI among 125 included studies was 23 (range 1-322). The FI was ≤10 in 35 studies (28%), 11-20 in 21 (17%), and >20 in 69 (55%). The median FI/Nexp was 7.7% (range 0.1-51.7%). The median FI was significantly lower among approvals processed through the accelerated vs regular pathway (5.5 vs 25, p = 0.001), but there was no difference in median FI/Nexp. The WCLFU exceeded FI in 42% of studies. Overall survival endpoints were more likely to have a WCLFU exceeding FI (OR 3.16, p = 0.003). WCLFU exceeding FI was also associated with a lesser magnitude of effect (median HR 0.69 vs 0.55, p FI. Conclusion: The median FI among all trials was 23, and WCLFU exceeded FI in 42%. Comparative trials in solid tumors supporting approval through the accelerated pathway are more fragile compared to trials approved through the regular pathway, an observation likely explained by a lower sample size in the experimental arm
Spinal cord injury in the emergency context: Review of program outcomes of a spinal cord injury rehabilitation program in Sri Lanka
Background: The final months of the conflict in Sri Lanka in 2009 resulted in massive displacement of the civilian population and a high volume of orthopedic trauma including spinal cord injury. In response to this need, Médecins Sans Frontières implemented a multidisciplinary rehabilitation program. Methods. Patients were admitted to the program if they had a spinal cord injury
Groundwater : meltwater interaction in a proglacial aquifer
Groundwater plays a significant role in the hydrology of active glacial catchments, with evidence that it may buffer changes in meltwater river flow and partially compensate for glacial loss. However, to date there has been little direct research into the hydrogeology and groundwater dynamics of proglacial aquifers. Here we directly investigate the three dimensional nature of a proglacial sandur (floodplain) aquifer in SE Iceland, using hydrogeological, geophysical, hydrological and stable isotopic techniques, and provide evidence of groundwater-melt water dynamics over three years.
We show that the proglacial sandur forms a thick (at least 50-100 m), high permeability (transmissivity up to 2500 m2/day) aquifer, extending over an area of approximately 6 km2. At least 35 million m3 of groundwater is stored in the aquifer, equivalent to ~23-28% of total annual river flow through the catchment. The volume of mean annual groundwater flow through the aquifer is at least 0.1-1 m3/sec, equivalent to ~10-20% of mean annual river flow. Groundwater across the aquifer is actively recharged from local precipitation and strongly influenced by individual rainfall events and seasonal precipitation. Glacial meltwater influence on groundwater also occurs in a zone extending from 20-500 m away from the meltwater river, for at least 3km down-sandur, and to at least 15 m deep. Within this zone summer recharge from the river to groundwater occurs when meltwater river flows are high, maintaining high summer groundwater levels compared to winter levels; and groundwater temperature and chemistry are strongly influenced by meltwater. Beyond this zone there is no substantial meltwater influence on groundwater.
From ~2 km down-sandur there is extensive groundwater discharge via springs, supporting semi-perennial streams that form distinct local ecosystems, and providing baseflow to the main meltwater river.
This research indicates that predicted continued climate change-related reductions in glacier coverage and increases in precipitation are likely to increase the significance of groundwater storage as a water resource, and of groundwater discharges in maintaining environmental river flows in glacier catchments
Electron spin coherence in semiconductors: Considerations for a spin-based solid state quantum computer architecture
We theoretically consider coherence times for spins in two quantum computer
architectures, where the qubit is the spin of an electron bound to a P donor
impurity in Si or within a GaAs quantum dot. We show that low temperature
decoherence is dominated by spin-spin interactions, through spectral diffusion
and dipolar flip-flop mechanisms. These contributions lead to 1-100 s
calculated spin coherence times for a wide range of parameters, much higher
than former estimates based on measurements.Comment: Role of the dipolar interaction clarified; Included discussion on the
approximations employed in the spectral diffusion calculation. Final version
to appear in Phys. Rev.
The impact of community expectations on corporate community involvement disclosures in the UK
Despite increase mistrust between corporations and societies in the aftermath of the global corporate misbehaviours, the literature examining the impact of community concerns on corporate communications is undeveloped. Our paper is timely; it contributes to the literature on corporate social responsibility (CSR) by considering the impacts of community expectations on Corporate Community Involvement Disclosures (CCID) using a ten-year panel study. We advance CSR communication research by providing a fresh theoretical perspective – media-agenda-setting theory – to the broad CSR debate and the CCID subset of this debate. Our findings support the media-agenda theoretical expectation and provide important practice and policy recommendations for improving interactions between corporations and their communities
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