Background: Choosing Wisely Canada and most major anesthesia and preoperative guidelines recommend against obtaining preoperative tests before low-risk procedures. However, these recommendations alone have not reduced low-value test ordering. In this study, the theoretical domains framework (TDF) was used to understand the drivers of preoperative electrocardiogram (ECG) and chest X-ray (CXR) ordering for patients undergoing low-risk surgery ('low-value preoperative testing') among anesthesiologists, internal medicine specialists, nurses, and surgeons.
View Article and Find Full Text PDFWe theoretically and experimentally investigate Tamm plasmon (TP) modes in a metal/semiconductor distributed Bragg reflector (DBR) interface. A thin Ag (silver) layer with a thickness (55 nm from simulation) that is optimized to guarantee a low reflectivity at the resonance was deposited on nanoporous GaN DBRs fabricated using electrochemical (EC) etching on freestanding semipolar (2021¯) GaN substrates. The reflectivity spectra of the DBRs are compared before and after the Ag deposition and with that of a blanket Ag layer deposited on GaN.
View Article and Find Full Text PDFThe electrical and optical improvements of AlGaInP micro-light-emitting diodes (µLEDs) using atomic-layer deposition (ALD) sidewall passivation were demonstrated. Due to the high surface recombination velocity and minority carrier diffusion length of the AlGaInP material system, devices without sidewall passivation suffered from high leakage and severe drop in external quantum efficiency (EQE). By employing ALD sidewall treatments, the 20×20 µm µLEDs resulted in greater light output power, size-independent leakage current density, and lower ideality factor.
View Article and Find Full Text PDFACS Appl Mater Interfaces
February 2018
Solid-state lighting using laser diodes is an exciting new development that requires new phosphor geometries to handle the greater light fluxes involved. The greater flux from the source results in more conversion and therefore more conversion loss in the phosphor, which generates self-heating, surpassing the stability of current encapsulation strategies used for light-emitting diodes, usually based on silicones. Here, we present a rapid method using spark plasma sintering (SPS) for preparing ceramic phosphor composites of the canonical yellow-emitting phosphor Ce-doped yttrium aluminum garnet (Ce:YAG) combined with a chemically compatible and thermally stable oxide, α-AlO.
View Article and Find Full Text PDFWe demonstrate that quality factors up to 5000 can be obtained in Tamm-like hybrid metal/semiconductor structures. To do this, a Bragg mirror is covered by a thin transparent layer and a metallic film. The reduced losses of these modes are related to an intermediate behavior between conventional Tamm plasmon and Bragg modes lying deeper in the semiconductor medium.
View Article and Find Full Text PDFWe demonstrate that confined Tamm plasmon modes can be advantageously exploited for the realization of new kind of metal/semiconductor lasers. Laser emission is demonstrated for Tamm structures with various diameters of the metallic disks which provide the confinement. A reduction of the threshold with the size is observed.
View Article and Find Full Text PDFActivated sphingomyelinases release ceramide molecules believed to be involved in intracellular signalling. The present study investigated whether soluble C2-ceramide modulates some of the effects of N-formylmethionylleucyl phenylalanine (fMLP) and other agonists on human neutrophils (or polymorphonuclear leukocytes-PMN); principally superoxide anion (O2-) production. The preincubation of PMN for 15 min with C2-ceramide increased by up to almost 3-fold the amounts of O2- generated in response to 0.
View Article and Find Full Text PDFInterleukin-8 (IL-8) and the structurally related cytokines neutrophil-activating peptide-2 (NAP-2) and GRO alpha are powerful chemotactic agents for human neutrophils. Although these three chemokines act by binding to overlapping but not identical receptor subsets, the data available to date have stressed the similarities in their mechanisms of action. The present studies were undertaken to further our understanding of the signal transduction mechanisms associated with these neutrophil agonists.
View Article and Find Full Text PDFWe used the excimer/monomer ratio of pyrene (PY) and N-(1-pyrenesulfonyl)dipalmitoyl-L-alpha-phosphatidylethanolamine (DPPE-PY) fluorescence intensities (IE/IM), and the polarity ratio I/III to investigate the state of the polar head group region of small, unilamellar phosphatidylcholine vesicles (SUV-PC) solubilized in media of differing NaCl concentrations. PY or DPPE-PY excimer formation resulting from vesicles' collisions is not affected by the presence of monovalent ions. In addition, the ionic strength does not alter the dielectric environment in the neighborhood of PY incorporated into SUV-PC.
View Article and Find Full Text PDFThe excimer/monomer ratio of emission intensities (IE/IM) and the enhancement of the 0-0 vibronic transition in the fluorescence spectra of pyrene (PY) and 16-(1-pyrenyl)hexadecanoic acid (C16PY) were used to investigate the localization of PY in the bilayers of small unilamellar vesicles constituted of phosphatidylcholine (SUV-PC). First, from comparison of the fluorescence characteristics of PY in water with those of PY incorporated into the SUV-PC membranes, we concluded that the probe is incorporated preferentially in the lipid phase of the vesicles and not in the bulk aqueous phase. In addition, we found that, contrary to what happens with the pyrenyl moiety of C16PY, the location of PY varies with its relative concentration in the membrane space.
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