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To assess the clinical effectiveness of a universal screening program compared with a risk factor–based program in reducing the rates of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) among admitted patients at the Ottawa Hospital.
Ottawa Hospital, a multicenter tertiary care facility with 3 main campuses, approximately 47,000 admissions per year, and 1,200 beds.
From January 1, 2006 through December 31, 2007 (24 months), admitted patients underwent risk factor–based MRSA screening. From January 1, 2008 through August 31, 2009 (20 months), all patients admitted underwent universal MRSA screening. To measure the effectiveness of this intervention, segmented regression modeling was used to examine monthly nosocomial MRSA incidence rates per 100,000 patient-days before and during the intervention period. To assess secular trends, nosocomial Clostridium difficile infection, mupirocin prescriptions, and regional MRSA rates were investigated as controls.
The nosocomial MRSA incidence rate was 46.79 cases per 100,000 patient-days, with no significant differences before and after intervention. The MRSA detection rate per 1,000 admissions increased from 9.8 during risk factor–based screening to 26.2 during universal screening. A total of 644 new nosocomial MRSA cases were observed in 1,448,488 patient-days, 323 during risk factor–based screening and 321 during universal screening. Secular trends in C. difficile infection rates and mupirocin prescriptions remained stable after the intervention whereas population-level MRSA rates decreased.
At Ottawa Hospital, the introduction of universal MRSA admission screening did not significantly affect the rates of nosocomial MRSA compared with risk factor–based screening.
The objective of this study was to determine whether skin and soft tissue infections (SSTIs) caused by methicillin-resistant Staphylococcus aureus (MRSA) in patients presenting to The Ottawa Hospital emergency departments (TOHEDs) differed from SSTIs caused by methicillin-susceptible Staphylococcus aureus (MSSA) with regard to risk factors, management, and outcomes.
All patients seen at TOHEDs in 2006 and 2007 with SSTIs who yielded MRSA or MSSA in cultures from the site of infection were eligible for inclusion. We excluded patients with decubitus ulcers and infections related to diabetes or peripheral vascular disease. We used an unmatched case-control design. Cases were defined as patients with MRSA isolated from the infection site, and controls were defined as patients with MSSA isolated from the infection site. Data were collected retrospectively from health records and laboratory and hospital information systems.
A total of 153 patients were included in the study (81 cases and 72 controls). The mean age of cases was 37 years, compared to 47 years for the controls (p < 0.001). Cases were more likely to have transient residence (31% v. 3% [OR 15.6, 95% CI 3.9–61.8, p < 0.001]), present with abscesses (64% v. 15% [OR 9.9, 95% CI 4.3–23.7, p < .001]), have a documented history of hepatitis C infection (28% v. 3% [OR 13.9, 95% CI 3.9–55.0, p < 0.001]), and have a history of substance abuse (53% v. 10% [OR 10.5, 95% CI 4.4–25.1, p < 0.001]). Cases most commonly used crack cocaine and injection drugs.
SSTIs caused by MRSA at TOHEDs mainly occur in a population that is young and transient with comorbidities such as hepatitis C and substance abuse.
The bombardment of C with 100 keV and 1 MeV W at normal incidence is studied as a function of the incident W fluence experimentally and by computer simulation with the program TRIDYN. Calculated oscillations in the amount of retained W and in the target weight change are confirmed experimentally for 100 keV at room temperature. XPS investigations show W2C formation during ion implantation already at room temperature. RBS depth profiles for 1 MeV bombardment show W mobility and surface segregation even at liquid nitrogen (LN2) temperatures. At elevated temperatures W clusters to form nano-particles at the surface and the oscillations in the retained amount of W disappear.
Carbon nanotubes and nanofibres are typically synthesised under substrate temperatures above 600°C. Here we investigate the influence of the substrate temperature and the plasma conditions on the growth of vertically aligned carbon nanostructures using Direct Current plasma Chemical Vapour Deposition, at temperatures below 550°C. These nanostructures are produced using a C2H2 based plasma and nickel thin film as the catalyst. We found that preferential deposition of amorphous carbon takes place as the synthesis temperature is lowered below 500°C. However, lowering the carbon concentration in the gas feedstock (<2% conc.) allows for the nucleation of nanofibre-like structures, whilst balancing the buildup of amorphous carbon. This method allows for the synthesis of vertically aligned structures at low temperatures (around 230°C) without intentional heating, while still achieving reasonable average growth rates up to 27 nm/min. The only heating was provided by the plasma, which typically consumes ∼ 4 W/cm2. It was found that by varying the applied plasma bias during high temperature synthesis, we increased the growth rate up to 165 nm/min. Based on the observations of experimental process variations and the morphology of the synthesised structures, we propose a growth mechanism for such low temperature growth and examine the resulting morphology changes.
In this article we discuss the applicability of global
scattering functions for structure analysis of Grazing Incidence Small Angle
X-ray Scattering (GISAXS) data. Contrary to rigorous analysis of the full
2-D detector image, which can be performed with complex simulation models,
the global scattering functions described here will be used to model
transverse detector scans in the
planes. In contrast to a full GISAXS analysis, this procedure cannot explain
structural features perpendicular to the sample plane. The discussed method
is useful for the analysis of weakly correlated films. These films are e.g.
found in polymer inorganic composite materials based on commercially
available nanoparticles. In hybrid material systems polydisperse structures,
including particle aggregates without precisely defined shape are formed.
The pictured approach, which models scattering in terms of structural
levels, has been previously applied with success in conventional
transmission SAXS geometry. It is based on conventional exponential and
power laws. Hence, data analysis becomes less complex compared to simulation
approaches. Here we examine if this unified fitting model can be used to
model diffuse, non specular scattering resulting from GISAXS. In this
context the applicability and limit of its application to diffuse scattering
in the GISAXS geometry is discussed. Furthermore diffuse
scattering from different ideal particle types is simulated and compared
with fitted results. To verify our approach, fit results from experimental
GISAXS curves obtained for real samples are compared with results from
Scanning Probe Microscopy and Scanning Electron Microscopy studies. The
samples investigated range from evaporated Au films to hybrid
TiO2/polymer films and demonstrate the usefulness in the structural
analysis of complex films.
Prions cause various transmissible spongiform encephalopathies. They are highly resistant to the chemical and physical decontamination and sterilization procedures routinely used in healthcare facilities. The decontamination procedures recommended for the inactivation of prions are often incompatible with the materials used in medical devices. In this study, we evaluated the use of low-temperature hydrogen peroxide gas plasma sterilization systems and other instrument-processing procedures for inactivating human and animal prions. We provide new data concerning the efficacy of hydrogen peroxide against prions from in vitro or in vivo tests, focusing on the following: the efficiency of hydrogen peroxide sterilization and possible interactions with enzymatic or alkaline detergents, differences in the efficiency of this treatment against different prion strains, and the influence of contaminating lipids. We found that gaseous hydrogen peroxide decreased the infectivity of prions and/or the level of the protease-resistant form of the prion protein on different surface materials. However, the efficiency of this treatment depended strongly on the concentration of hydrogen peroxide and the delivery system used in medical devices, because these effects were more pronounced for the new generation of Sterrad technology. The Sterrad NX sterilizer is 100% efficient (0% transmission and no protease-resistant form of the prion protein signal detected on the surface of the material for the mouse-adapted bovine spongiform encephalopathy 6PB1 strain and a variant Creutzfeldt-Jakob disease strain). Thus, gaseous or vaporized hydrogen peroxide efficiently inactivates prions on the surfaces of medical devices.
EURECA (European Underground Rare Event Calorimeter Array) is an
astro-particle physics facility aiming to directly detect galactic dark
matter. The Laboratoire Souterrain de Modane has been selected as host
laboratory. The EURECA collaboration unites CRESST, EDELWEISS and the
Spanish-French experiment ROSEBUD, thus concentrating and focussing effort
on cryogenic detector research in Europe into a single facility. EURECA will
use a target mass of up to one ton, enough to explore WIMP – nucleon scalar
scattering cross sections in the region of 10-9 – 10-10 picobarn.
A major advantage of EURECA is the planned use of more than just one target
material (multi target experiment for WIMP identification).
To assess the impact of real-time polymerase chain reaction (PCR) detection of methicillin-resistant Staphylococcus aureus (MRSA) on nosocomial transmission and costs.
Monthly MRSA detection rates were measured from April 1, 2000, through December 31, 2005. Time series analysis was used to identify changes in MRSA detection rates, and decision analysis was used to compare the costs of detection by PCR and by culture.
A 1,200-bed, tertiary care hospital in Canada.
Admitted patients at high risk for MRSA colonization. MRSA detection using culture-based screening was compared with a commercial PCR assay.
The mean monthly incidence of nosocomial MRSA colonization or infection was 0.37 cases per 1,000 patient-days. The time-series model indicated an insignificant decrease of 0.14 cases per 1,000 patient-days per month (95% confidence interval, —0.18 to 0.46) after the introduction of PCR detection (P = .39). The mean interval from a reported positive result until contact precautions were initiated decreased from 3.8 to 1.6 days (P<.001). However, the cost of MRSA control increased from Can$605,034 to Can$771,609. Of 290 PCR-positive patients, 120 (41.4%) were placed under contact precautions unnecessarily because of low specificity of the PCR assay used in the study; these patients contributed 37% of the increased cost. The modeling study predicted that the cost per patient would be higher with detection by PCR (Can$96) than by culture (Can$67).
Detection of MRSA by the PCR assay evaluated in this study was more costly than detection by culture for reducing MRSA transmission in our hospital. The cost benefit of screening by PCR varies according to incidences of MRSA colonization and infection, the predictive values of the assay used, and rates of compliance with infection control measures.
The X-ray spectral distribution of swift heavy Ti and Ni ions
(11 MeV/u) observed inside aerogels (ρ = 0.1
g/cm3) and dense solids (quartz, ρ = 2.23
g/cm3) indicates a strong presence of simultaneous
3–5 charge states with one K-hole. We show that the
theoretical analysis can be split into two tasks: first, the
treatment of complex autoionizing states together with the
originating spectral distribution, and, second, a charge-state
distribution model. Involving the generalized line profile function
theory, we discuss attempts to couple charge-state distributions.
The hydrodynamic response of metal targets to volume
heating by energy deposition of intense heavy-ion beams
was investigated experimentally. Recent improvements in
beam parameters led to a marked increase in specific deposition
ions of 300 MeV/u focused to a spot size of 300 μm
(σ) × 540 μm (σ) yield a specific deposition
energy in solid lead of approximately 1 kJ/g in the Bragg
peak, delivered within 250 ns [full width at half
maximum (FWHM)]. This value allowed us for the first
time to observe heavy-ion-beam-induced hydrodynamic expansion
of metal volume targets. Measurements comprise expansion
velocities of free surfaces of up to 290 ± 20 m/s,
surface temperatures of ejected target matter of 1600–1750
K, and pressure waves in solid metal bulk targets of 0.16
GPa maximum absolute value and 0.8 μs FWHM. The experimental
results agree well with the results of a 2D hydrodynamic
code. Inside the interaction zone, which can only be accessed
by simulation, maximum temperatures are 2800 K and maximum
pressures are 3.8 GPa.
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