4,232 research outputs found
Estimation procedure of the descriptor LAeq,T from the stabilization time of the sound pressure level value
Temporal structure of sound pressure level is
a key aspect at the time of characterizing
urban sound environments. In urban
agglomerations, environmental noise levels
fluctuate over a large range as a result of
the great complexity of these settings, with
considerable temporal and spatial
heterogeneity. Furthermore, the domain in
urban environments of noise sources, such
as road traffic, commercial or leisure
activities, construction works, etc., together
with the occurrence of sudden sound-level
maxima events (bells, sirens, vehicles at high
traffic speed, honking horns...), which are
quite frequent in urban agglomerations,
generate the appearance of very high values
of the impulsiveness of sound pressure level.
This aspect causes a great influence on the
time necessary for environmental noise
levels to become stabilized, which is a key
aspect for the accurate measurement,
interpretation and guarantee of a
statistically representative sample of a
given urban sound environment. Therefore,
the goal pursued in this work is to put forth a
procedure for the calculation of a value of
LAeq,T, representative of a certain urban
location in a short-term time period, from the
utilization of the value of the stabilization
time of the sound pressure level
Do Economic Evaluations in Primary Care Prevention and the Management of Hypertension Conform to Good Practice Guidelines? A Systematic Review
Background: Results of previous research have identified the need for further investigation into the compliance with good practice guidelines for current decision-analytic modeling (DAM). Objective: To identify the extent to which recent model-based economic evaluations of interventions focused on lowering the blood pressure (BP) of patients with hypertension conform to published guidelines for DAM in health care using a five-dimension framework developed to assess compliance to DAM guidelines. Methods: A systematic review of English language articles was undertaken to identify published model-based economic evaluations that examined interventions aimed at lowering BP. The review covered the period January 2000 to March 2015 and included the following electronic bibliographic databases: EMBASE and Medline via Ovid interface and the Centre for Reviews and Disseminationâs (CRD) NHS-EED. Data were extracted based on different components of good practice across five dimensions utilizing a framework to assess compliance to DAM guidelines. Results: Thirteen articles were included in this review. The review found limited compliance to good practice DAM guidelines, which was most frequently justified by the lack of data. Conclusions: The assessment of structural uncertainty cannot yet be considered common practice in primary prevention and management of hypertension, and researchers seem to face difficulties with identifying sources of structural uncertainty and then handling them correctly. Additional guidelines are needed to aid researchers in identifying and managing sources of potential structural uncertainty. Adherence to guidelines is not always possible and it does pose challenges, in particular when there are limitations due to data availability that restrict, for example, a validation process
Weaning of immunosuppression in long - Term liver transplant recipients
Seventy-two long-surviving liver transplant recipients were evaluated prospectively, including a baseline allograft biopsy for weaning off of immunosuppression. Thirteen were removed from candidacy because of chronic rejection (n=4), hepatitis (n=2), patient anxiety (n=5), or lack of cooperation by the local physician (n=2). The other 59, aged 12-68 years, had stepwise drug weaning with weekly or biweekly monitoring of liver function tests. Their original diagnoses were PBC (n=9), HCC (n=l), Wilsonâs disease (n=4), hepatitides (n=15), Laennecâs cirrhosis (n=l), biliary atresia (n=16), cystic fibrosis (n=l), hemochromatosis (n=l), hepatic trauma (n=l), alpha-l-antitrypsin deficiency (n=9), and secondary biliary cirrhosis (n=l). Most of the patients had complications of long-term immunosuppression, of which the most significant were renal dysfunction (n=8), squamous cell carcinoma (n=2) or verruca vulgaris of skin (n=9), osteoporosis and/or arthritis (n=12), obesity (n=3), hypertension (n=ll), and opportunistic infections (n=2). When azathioprine was a third drug, it was stopped first. Otherwise, weaning began with prednisone, using the results of corticotropin stimulation testing as a guide. If adrenal insufficiency was diagnosed, patients reduced to <5 mg/day prednisone were considered off of steroids. The baseline agents (azathioprine, cyclospo-rine, or FK506) were then gradually reduced in monthly decrements. Complete weaning was accomplished in 16 patients (27.1%) with 3-19 months drug-free follow-up, is progressing in 28 (47.4%), and failed in 15 (25.4%) without graft losses or demonstrable loss of graft function from the rejections. This and our previous experience with self-weaned and other patients off of immunosuppression indicate that a significant percentage of appropriately selected long-surviving liver recipients can unknowingly achieve drug-free graft acceptance. Such attempts should not be contemplated until 5-10 years posttransplantation and then only with careful case selection, close monitoring, and prompt reinstitution of immunosuppression when necessary. © 1995 by Williams & Wilkins
Cell migration and chimerism after wholeâorgan transplantation: The basis of graft acceptance
Improvements in the prevention or control of rejection of the kidney and liver have been largely interchangeable (1, 2) and then applicable, with very little modification, to thoracic and other organs. However, the mechanism by which anti rejection treatment permits any of these grafts to be âacceptedâ has been an immunological enigma (3, 4). We have proposed recently that the exchange of migratory leukocytes between the transplant and the recipient with consequent long-term cellular chimerism in both is the basis for acceptance of all whole-organ allografts and xenografts (5). Although such chimerism was demonstrated only a few months ago, the observations have increased our insight into transplantation immunology and have encouraged the development of alternative therapeutic strategies (6)
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Carbon nanotube isolation layer enhancing in-liquid quality-factors of thin film bulk acoustic wave resonators for gravimetric sensing
A thickness longitudinal mode (TLM) thin film bulk acoustic resonator biosensor is demonstrated to operate in water with a high quality-factor, Q. This is achieved using a layer of carbon nanotubes (CNTs) on top of the resonator which has a significantly different acoustic impedance to either the resonator or liquid whilst being susceptible to the binding of biological molecules. This allows the resonance to be decoupled from direct energy loss into the liquid, although still retaining mass sensitivity. AlN solidly mounted resonators (SMRs) having a thickness shear mode (TSM) at 1.1 GHz and TLM at 1.9 GHz are fabricated. CNTs with different forest densities are grown by chemical vapor deposition on the active area with Fe as catalyst and resulting devices compared. High forest density CNTs are shown to acoustically decouple the SMRs from the water and in-liquid TLM Q values higher than 150 are recorded even exceeding TSM SMRs without CNTs. The TLM Q in water is remarkably improved from 3 to 160 for the first time by dense CNT forests, rendering the large-scale fabrication of TLM SMRs for liquid-phase sensing applications possible. Despite this partial
isolation, SMRs with CNT forests ~15 ÎŒm tall can still detect binding of bovine serum albumin.This work was supported by the European Community's Horizon 2020 Programme [grant number SPIRE-01-2014-636820 (RECOBA)]; and the Ministerio de EconomĂa y Competitividad del Gobierno de España [grant number MAT2013-45957-R]. G.R. and S.Z. also wish to acknowledge funding from the Cambridge Commonwealth, European and International Trust
Chimerism and donor-specific nonreactivity 27 to 29 years after kidney allotransplantation
Chimerism was demonstrated with immunocytochemical and/or polymerase chain reaction techniques in kidney allografts and in the native skin, lymph nodes, or blood of 5 of 5 patients who received continuously functioning renal transplants from 1 or 2 haplotype HLA mismatched consanguineous donors (4 parents, 1 aunt) 27-29 years ago. In the 4 cases where the kidney donor still was alive to provide stimulator lymphocytes for testing, these provoked no (n=2) or modest (n=2) MLR in contrast to vigorous MLR to third party lymphocytes. In all 4 cases, the donor cells failed to generate in vitro cytotoxic effector cells (cell-mediated lymphocytotoxicity). These findings are in accord with the hypothesis that cell migration, repopulation, and chimerism are seminal events that define graft acceptance and ultimately can lead to acquired donor-specific nonresponsiveness (tolerance). © 1993 Williams and wilkins
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