126 research outputs found
Soft Targets: Nurses and the Pharmaceutical Industry
The nursing literature has yet to pay much attention to the expansive reach of the pharmaceutical industry into the nursing profession
A new Holocene eruptive history of Erebus volcano, Antarctica using cosmogenic 3He and 36Cl exposure ages
AbstractThe ages of recent effusive eruptions on Erebus volcano, Antarctica are poorly known. Published 40Ar/39Ar ages of the 10 youngest “post-caldera” lava flows are unreliable because of the young ages of the flows (<10 ka) and the presence of excess 40Ar. Here we use cosmogenic 3He and 36Cl to provide new ages for the 10 youngest flows and 3 older summit flows, including a newly recognized flow distinguished by its exposure age. Estimated eruption ages of the post-caldera flows, assuming no erosion or prior snow cover, range from 4.52 ± 0.08 ka to 8.50 ± 0.19 ka, using Lifton et al. (2014) to scale cosmogenic production rates. If the older Lal (1991)/Stone (2000) model is used to scale production rates, calculated ages are older by 16–25%. Helium-3 and chlorine-36 exposure ages measured on the same samples show excellent agreement. Helium-3 ages measured on clinopyroxene and olivine from the same samples are discordant, probably due in part to lower-than-expected 3He production rates in the Fe-rich olivine. Close agreement of multiple clinopyroxene 3He ages from each flow indicates that the effects of past snow coverage on the exposure ages have been minimal.The new cosmogenic ages differ considerably from published 40Ar/39Ar and 36Cl ages and reveal that the post-caldera flows were erupted during relatively brief periods of effusive activity spread over an interval of ∼4 ka. The average eruption rate over this interval is estimated to be 0.01 km3/ka. Because the last eruption was at least 4 ka ago, and the longest repose interval between the 10 youngest eruptions is ∼1 ka, we consider the most recent period of effusive activity to have ended
Mechanisms of occlusion of uncoated self-expanding metal biliary stents(SEMS): Final results of a multi-center comparative study
PEAK IDENTIFICATION IN LIQUID CHROMATOGRAPHY BY MEANS OF FLUORESCENCE LIFETIME DETERMINATION
Peak identification in liquid chromatography is most often performed on the basis of retention time alone. In many cases, especially in the analysis of complex samples, this is inadequate. A number of successful attempts have been made at providing an additional means of selectivity so that peak identity can be confirmed, the vast majority of which are spectroscopic in nature. This dissertation describes a new method for positive peak identification in liquid chromatography which also relies upon spectroscopy for the additional selectivity. Specifically, the fluorescence lifetime of an eluting compound is measured, which, when combined with chromatographic retention time, provides sufficient information for the unambiguous identification of an unknown. Preliminary experiments leading up to actual on-the-fly lifetime measurement are described, followed by demonstration of the principles of the new technique with flow-injection analysis. A detailed discussion of the factors affecting the precision and accuracy of the method is included along with practical application to the chromatographic determination of polycyclic aromatic hydrocarbons in combustion products. Finally, suggestions for future work are made, including experiments designed to advance the understanding of the method itself, as well as potential new applications
GI endoscopes
The ASGE Technology Committee provides reviews of existing, new, or emerging endoscopic technologies that have an impact on the practice of GI endoscopy. Evidence-based methodology is used, performing a MEDLINE literature search to identify pertinent clinical studies on the topic and a MAUDE (U.S. Food and Drug Administration Center for Devices and Radiological Health) database search to identify the reported complications of a given technology. Both are supplemented by accessing the related articles feature of PubMed and by scrutinizing pertinent references cited by the identified studies. Controlled clinical trials are emphasized, but in many cases data from randomized, controlled trials are lacking. In such cases, large case series, preliminary clinical studies, and expert opinions are used. Technical data are gathered from traditional and Web-based publications, proprietary publications, and informal communications with pertinent vendors. Technology Status Evaluation Reports are drafted by 1 or 2 members of the ASGE Technology Committee, reviewed and edited by the Committee as a whole, and approved by the Governing Board of the ASGE. When financial guidance is indicated, the most recent coding data and list prices at the time of publication are provided. For this review, the MEDLINE database was searched through September 2010 for articles related to endoscopy by using the key words gastroscope, colonoscope, echoendoscope, duodenoscope, choledochoscope, ultraslim endoscope, variable stiffness colonoscope, and wide-angle colonoscope. Technology Status Evaluation Reports are scientific reviews provided solely for educational and informational purposes. Technology Status Evaluation Reports are not rules and should not be construed as establishing a legal standard of care or as encouraging, advocating, requiring, or discouraging any particular treatment or payment for such treatment. Copyright © 2011 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved
Multicenter randomized trial of the spiral Z-stent compared with the Wallstent for malignant biliary obstruction.
BACKGROUND: The industry standard since 1990 for self-expanding biliary metallic stents has been the Wallstent. In 1998 the Spiral Z-stent was released. This randomized trial compared the Z-stent with the Wallstent in the treatment of malignant biliary o
Endoscopic 6 mm zilver self-expanding metal stents (SEMS) for malignant obstruction of the bifurcation: a pilot study
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