Search results for "ULTRAVIOLET"
showing 10 items of 853 documents
Enhanced terminal room disinfection and acquisition and infection caused by multidrug-resistant organisms and Clostridium difficile (the Benefits of …
2017
Summary Background Patients admitted to hospital can acquire multidrug-resistant organisms and Clostridium difficile from inadequately disinfected environmental surfaces. We determined the effect of three enhanced strategies for terminal room disinfection (disinfection of a room between occupying patients) on acquisition and infection due to meticillin-resistant Staphylococcus aureus , vancomycin-resistant enterococci, C difficile , and multidrug-resistant Acinetobacter . Methods We did a pragmatic, cluster-randomised, crossover trial at nine hospitals in the southeastern USA. Rooms from which a patient with infection or colonisation with a target organism was discharged were terminally dis…
Light exposure of the lower leg as a pathogenetic factor in the occurrence of malignant melanoma.
1992
Of the 1,198 women and men studied in Mainz from 1966 to 1987 there was an approximately fivefold increase in the incidence of melanoma. Among the men melanomas on the trunk (59.9%) predominated, whereas among the women melanomas on the extremities (40.0%) were more common, especially on the lower leg (26.3%). Comparing the decades 1966-1976 and 1977-1987 there was a significant decrease in melanomas affecting women's lower legs (1966-1976: 33%,; 1977-1987: 24.2%). Fashion-dependent sun exposure of this body area might offer an explanation. It could be demonstrated that common stocking materials do not sufficiently protect against UV radiation (average permeability for UV light about 55%), …
Vitamin D and cutaneous lupus erythematosus: effect of vitamin D replacement on disease severity.
2014
Background The main vitamin D source is exposure to ultraviolet radiation, which aggravates cutaneous lupus erythematosus (CLE). Objectives The aims of this study were to identify variables associated with lower serum 25-hydroxyvitamin D [25(OH)D] levels in CLE patients and assess the effect of vitamin D restoration on disease severity. Methods Vitamin D status in 60 CLE patients and 117 apparently healthy subjects was compared. We recommended oral vitamin D3 to 27 CLE patients. After one year of treatment, changes in disease severity were assessed and compared to 25 untreated CLE patients. Disease severity was measured by the Cutaneous Lupus Erythematosus Disease Area and Severity Index (C…
Variability in protein binding of teicoplanin and achievement of therapeutic drug monitoring targets in critically ill patients: Lessons from the DAL…
2014
The aims of this study were to describe the variability in protein binding of teicoplanin in critically ill patients as well as the number of patients achieving therapeutic target concentrations. This report is part of the multinational pharmacokinetic DALI Study. Patients were sampled on a single day, with blood samples taken both at the midpoint and the end of the dosing interval. Total and unbound teicoplanin concentrations were assayed using validated chromatographic methods. The lower therapeutic range of teicoplanin was defined as total trough concentrations from 10 to 20 mg/L and the higher range as 10-30 mg/L. Thirteen critically ill patients were available for analysis. The followi…
Electrochemistry and Spectroelectrochemistry of Bismanganese Porphyrin-Corrole Dyads
2011
A series of homobimetallic manganese cofacial porphyrin-corrole dyads were synthesized and investigated as to their electrochemistry, spectroelectrochemistry, and ligand binding properties in nonaqueous media. Four dyads were investigated, each of which contained a Mn(III) corrole linked in a face-to-face arrangement with a Mn(III) porphyrin. The main difference between compounds in the series is the type of spacer, 9,9-dimethylxanthene, anthracene, dibenzofuran, or diphenylether, which determines the distance and interaction between the metallomacrocycles. Each redox process of the porphyrin-corrole dyads was assigned on the basis of spectroscopic and electrochemical data and by comparison…
Why the Cosmological Constant Seems to Hardly Care About Quantum Vacuum Fluctuations: Surprises From Background Independent Coarse Graining
2020
International audience; Background Independence is a sine qua non for every satisfactory theory of Quantum Gravity. In particular if one tries to establish a corresponding notion of Wilsonian renormalization, or coarse graining, it presents a major conceptual and technical difficulty usually. In this paper we adopt the approach of the gravitational Effective Average Action and demonstrate that generically coarse graining in Quantum Gravity and in standard field theories on a non-dynamical spacetime are profoundly different. By means of a concrete example, which in connection with the cosmological constant problem is also interesting in its own right, we show that the surprising and sometime…
Visible to vacuum-UV range optical absorption of oxygen dangling bonds in amorphous SiO2
2011
Synthetic silica glass with an optical absorption spectrum dominated by oxygen dangling bonds (nonbridging oxygen hole centers, or NBOHCs) and having negligible (1%) contribution from the usually copresent Si dangling bonds (E\ensuremath{'}-centers), was prepared by room temperature ultraviolet photobleaching of high SiOH content (``wet'') silica, irradiated by F${}_{2}$ laser (7.9 eV) at $T$ = 80 K. This allowed us to obtain the up-to-now controversial optical absorption spectrum of NBOHC in the ultraviolet and vacuum-ultraviolet (UV-VUV) region of the spectrum and to show that it is semicontinuous from 4 to 7.8 eV and cannot be represented by a pair of distinct Gaussian bands. Since NBOHC…
Resonance Raman of oxygen dangling bonds in amorphous silicon dioxide
2016
We investigate the origin of a resonance Raman band induced by ionizing radiation in amorphous silicon dioxide (silica glass), which can be detected under ultraviolet laser excitation. A silica sample, rich of oxygen-excess related defects, was prepared by treating some length of a pure-silica-core multimode fiber in an O2 atmosphere (at high temperature and pressure) and by irradiating it with X-rays at 10 MGy(SiO2) dose. A micro-Raman study revealed a gaussian band peaking at 896 cm−1 with a full width at half maximum of 32 cm−1, which could be detected by exciting the sample with the 325-nm line of a HeCd laser. This spectral feature is absent in the Raman spectra performed with the 442-…
Quantum size confinement in gallium selenide nanosheets: band gap tunability versus stability limitation
2017
Abstract Gallium selenide is one of the most promising candidates to extend the window of band gap values provided by existing two-dimensional semiconductors deep into the visible potentially reaching the ultraviolet. However, the tunability of its band gap by means of quantum confinement effects is still unknown, probably due to poor nanosheet stability. Here, we demonstrate that the optical band gap band of GaSe nanosheets can be tuned by ∼120 meV from bulk to 8 nm thick. The luminescent response of very thin nanosheets (<8 nm) is strongly quenched due to early oxidation. Oxidation favors the emergence of sharp material nanospikes at the surface attributable to strain relaxation. Simul…
Study of the bandgap renormalization in Ga-doped ZnO films by means of optical absorption under high pressure and photoelectron spectroscopy
2008
Abstract In this paper we investigate the band gap renormalization in heavily Ga-doped ZnO thin films deposited by pulsed laser deposition on C -plane sapphire and mica substrates. Thin films were studied by ultraviolet photoelectron spectroscopy and also by optical measurements under high pressure. The Fermi-level shift, as obtained from ultraviolet photoelectron experiments, exhibits a relatively small and positive shift (about 0.3 eV) with respect to the valence band for increasing electron concentrations up to 1021 cm−3. The optical gap exhibits a much larger increase (0.6 eV) for the same concentration range. Absorption measurements under pressure show that the pressure coefficient of …