Electron spin and cyclotron resonance of laser annealed silicon

EPR and cyclotron resonance investigations have been performed on laser annealed Si wafers, leading to the identification of the [V + O i]- complex in virgin Si and to a donor signal quenching in P-implanted Si

ELECTRON SPIN RESONANCE INVESTIGATION OF THE EFFECTS OF THE H2+ IMPLANTATION AND DIFFUSION ONE THE LASER INDUCED DEFECTS IN VIRGIN SILICON

Electron paramagnetic resonance of the defects induced by laser annealing at high power density (2 J/cm-2) has been investigated in virgin FZ semi-insulating Silicon. A further H2+ implantation and diffusion is inactive on the signal observed at gx = 2.0055 ± 0.0005. This is consistent with the attribution of X to the dangling bonds, created by the mechanical stresses during the thermal shock, as they are not passivated by molecular hydrogen

Gravitomagnetism and the Clock Effect

The main theoretical aspects of gravitomagnetism are reviewed. It is shown that the gravitomagnetic precession of a gyroscope is intimately connected with the special temporal structure around a rotating mass that is revealed by the gravitomagnetic clock effect. This remarkable effect, which involves the difference in the proper periods of a standard clock in prograde and retrograde circular geodesic orbits around a rotating mass, is discussed in detail. The implications of this effect for the notion of ``inertial dragging'' in the general theory of relativity are presented. The theory of the clock effect is developed within the PPN framework and the possibility of measuring it via spaceborne clocks is examined.Comment: 27 pages, LaTeX, submitted to Proc. Bad Honnef Meeting on: GYROS, CLOCKS, AND INTERFEROMETERS: TESTING GENERAL RELATIVITY IN SPACE (22 - 27 August 1999; Bad Honnef, Germany

Determination of the physical environment within the Chlamydia trachomatis inclusion using ion-selective ratiometric probes

Chlamydia trachomatis is an obligate intracellular bacterium with a biphasic life cycle that takes place entirely within a membrane-bound vacuole termed an inclusion. The chlamydial inclusion is non-fusogenic with endosomal or lysosomal compartments but intersects a pathway involved in transport of sphingomyelin from the Golgi apparatus to the plasma membrane. The physical conditions within the mature chlamydial inclusion are unknown. We used ratiometric imaging with membrane-permeant, ion-selective fluorescent dyes for microanalyis of the physical environment within the inclusion. Determination of H + , Na + , K + and Ca 2 + concentrations using CFDA (carboxy fluorescein diacetate) or BCECF-AM (2 ′ ,7 ′ -bis (2-carboxyethyl)-5,6-carboxyfluorescein acetoxymethyl ester, SBFI-AM, PBFI-AM and fura-PE3-acetomethoxyester (Fura-PE3-AM), respectively, indicated that all ions assayed within the lumenal space of the inclusion approximated the concentrations within the cytoplasm. Stimulation of purinergic receptors by addition of extracellular ATP triggered a dynamic Ca 2 + response that occurred simultaneously within the cytoplasm and interior of the inclusion. The chlamydial inclusion thus appears to be freely permeable to cytoplasmic ions. These results have implications for nutrient acquisition by chlamydiae and may contribute to the non-fusogenicity of the inclusion with endocytic compartments.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72253/1/j.1462-5822.2002.00191.x.pd

Partial Wave Analysis of the Reaction p(3.5GeV)+p→pK+Λp(3.5 GeV)+p \to pK^+\Lambda to Search for the "ppK−ppK^-" Bound State

Employing the Bonn-Gatchina partial wave analysis framework (PWA), we have analyzed HADES data of the reaction $p(3.5GeV)+p\to pK^{+}\Lambda$. This reaction might contain information about the kaonic cluster "$ppK^-$" via its decay into $p\Lambda$. Due to interference effects in our coherent description of the data, a hypothetical $\overline{K}NN$ (or, specifically "$ppK^-$") cluster signal must not necessarily show up as a pronounced feature (e.g. a peak) in an invariant mass spectra like $p\Lambda$. Our PWA analysis includes a variety of resonant and non-resonant intermediate states and delivers a good description of our data (various angular distributions and two-hadron invariant mass spectra) without a contribution of a $\overline{K}NN$ cluster. At a confidence level of CL$_{s}$=95\% such a cluster can not contribute more than 2-12\% to the total cross section with a $pK^{+}\Lambda$ final state, which translates into a production cross-section between 0.7 $\mu b$ and 4.2 $\mu b$, respectively. The range of the upper limit depends on the assumed cluster mass, width and production process.Comment: 7 Pages, 5 Figure

Production of Sigma{\pm}pi?pK+ in p+p reactions at 3.5 GeV beam energy

We study the production of Sigma^+-pi^+-pK^+ particle quartets in p+p reactions at 3.5 GeV kinetic beam energy. The data were taken with the HADES experiment at GSI. This report evaluates the contribution of resonances like Lambda(1405$, Sigma(1385)^0, Lambda(1520), Delta(1232), N^* and K^*0 to the Sigma^+- pi^-+ p K+ final state. The resulting simulation model is compared to the experimental data in several angular distributions and it shows itself as suitable to evaluate the acceptance corrections properly.Comment: 15 pages, 5 figure

Effectiveness of targeted enhanced terminal room disinfection on hospital-wide acquisition and infection with multidrug-resistant organisms and Clostridium difficile: a secondary analysis of a multicentre cluster randomised controlled trial with crossover design (BETR Disinfection)

Background: The hospital environment is a source of pathogen transmission. The effect of enhanced disinfection strategies on the hospital-wide incidence of infection has not been investigated in a multicentre, randomised controlled trial. We aimed to assess the effectiveness of four disinfection strategies on hospital-wide incidence of multidrug-resistant organisms and Clostridium difficile in the Benefits of Enhanced Terminal Room (BETR) Disinfection study. Methods: We did a prespecified secondary analysis of the results from the BETR Disinfection study, a pragmatic, multicentre, crossover cluster-randomised trial that assessed four different strategies for terminal room disinfection in nine hospitals in the southeastern USA. Rooms from which a patient with a specific infection or colonisation (due to the target organisms C difficile, meticillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci (VRE), or multidrug-resistant Acinetobacter spp) was discharged were terminally disinfected with one of four strategies: standard disinfection (quaternary ammonium disinfectant, except for C difficile, for which 10% hypochlorite [bleach] was used; reference); standard disinfection and disinfecting ultraviolet light (UV-C), except for C difficile, for which bleach and UV-C was used (UV strategy); 10% hypochlorite (bleach strategy); and bleach and UV-C (bleach and UV strategy). We randomly assigned the sequence of strategies for each hospital (1:1:1:1), and each strategy was used for 7 months, including a 1-month wash-in period and 6 months of data collection. The prespecified secondary outcomes were hospital-wide, hospital-acquired incidence of all target organisms (calculated as number of patients with hospital-acquired infection with a target organism per 10 000 patient days), and hospital-wide, hospital-acquired incidence of each target organism separately. BETR Disinfection is registered with ClinicalTrials.gov, number NCT01579370. Findings: Between April, 2012, and July, 2014, there were 271 740 unique patients with 375 918 admissions. 314 610 admissions met all inclusion criteria (n=73 071 in the reference study period, n=81 621 in the UV study period, n=78 760 in the bleach study period, and n=81 158 in the bleach and UV study period). 2681 incidenct cases of hospital-acquired infection or colonisation occurred during the study. There was no significant difference in the hospital-wide risk of target organism acquisition between standard disinfection and the three enhanced terminal disinfection strategies for all target multidrug-resistant organisms (UV study period relative risk [RR] 0·89, 95% CI 0·79–1·00; p=0·052; bleach study period 0·92, 0·79–1·08; p=0·32; bleach and UV study period 0·99, 0·89–1·11; p=0·89). The decrease in risk in the UV study period was driven by decreases in risk of acquisition of C difficile (RR 0·89, 95% CI 0·80–0·99; p=0·031) and VRE (0·56, 0·31–0·996; p=0·048). Interpretation: Enhanced terminal room disinfection with UV in a targeted subset of high-risk rooms led to a decrease in hospital-wide incidence of C difficile and VRE. Enhanced disinfection overcomes limitations of standard disinfection strategies and is a potential strategy to reduce the risk of acquisition of multidrug-resistant organisms and C difficile. Funding: US Centers for Disease Control and Prevention

Enhanced terminal room disinfection and acquisition and infection caused by multidrug-resistant organisms and Clostridium difficile (the Benefits of Enhanced Terminal Room Disinfection study): a cluster-randomised, multicentre, crossover study

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 disinfected with one of four strategies: reference (quaternary ammonium disinfectant except for C difficile, for which bleach was used); UV (quaternary ammonium disinfectant and disinfecting ultraviolet [UV-C] light except for C difficile, for which bleach and UV-C were used); bleach; and bleach and UV-C. The next patient admitted to the targeted room was considered exposed. Every strategy was used at each hospital in four consecutive 7-month periods. We randomly assigned the sequence of strategies for each hospital (1:1:1:1). The primary outcomes were the incidence of infection or colonisation with all target organisms among exposed patients and the incidence of C difficile infection among exposed patients in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT01579370. Findings 31 226 patients were exposed; 21 395 (69%) met all inclusion criteria, including 4916 in the reference group, 5178 in the UV group, 5438 in the bleach group, and 5863 in the bleach and UV group. 115 patients had the primary outcome during 22 426 exposure days in the reference group (51·3 per 10 000 exposure days). The incidence of target organisms among exposed patients was significantly lower after adding UV to standard cleaning strategies (n=76; 33·9 cases per 10 000 exposure days; relative risk [RR] 0·70, 95% CI 0·50–0·98; p=0·036). The primary outcome was not statistically lower with bleach (n=101; 41·6 cases per 10 000 exposure days; RR 0·85, 95% CI 0·69–1·04; p=0·116), or bleach and UV (n=131; 45·6 cases per 10 000 exposure days; RR 0·91, 95% CI 0·76–1·09; p=0·303) among exposed patients. Similarly, the incidence of C difficile infection among exposed patients was not changed after adding UV to cleaning with bleach (n=38 vs 36; 30·4 cases vs 31·6 cases per 10 000 exposure days; RR 1·0, 95% CI 0·57–1·75; p=0·997). Interpretation A contaminated health-care environment is an important source for acquisition of pathogens; enhanced terminal room disinfection decreases this risk. Funding US Centers for Disease Control and Prevention

Low Q^2 Jet Production at HERA and Virtual Photon Structure

The transition between photoproduction and deep-inelastic scattering is investigated in jet production at the HERA ep collider, using data collected by the H1 experiment. Measurements of the differential inclusive jet cross-sections dsigep/dEt* and dsigmep/deta*, where Et* and eta* are the transverse energy and the pseudorapidity of the jets in the virtual photon-proton centre of mass frame, are presented for 0 < Q2 < 49 GeV2 and 0.3 < y < 0.6. The interpretation of the results in terms of the structure of the virtual photon is discussed. The data are best described by QCD calculations which include a partonic structure of the virtual photon that evolves with Q2.Comment: 20 pages, 5 Figure