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To determine the impact of total household decolonization with intranasal mupirocin and chlorhexidine gluconate body wash on recurrent methicillin-resistant Staphylococcus aureus (MRSA) infection among subjects with MRSA skin and soft-tissue infection.
Three-arm nonmasked randomized controlled trial.
Five academic medical centers in Southeastern Pennsylvania.
Adults and children presenting to ambulatory care settings with community-onset MRSA skin and soft-tissue infection (ie, index cases) and their household members.
Enrolled households were randomized to 1 of 3 intervention groups: (1) education on routine hygiene measures, (2) education plus decolonization without reminders (intranasal mupirocin ointment twice daily for 7 days and chlorhexidine gluconate on the first and last day), or (3) education plus decolonization with reminders, where subjects received daily telephone call or text message reminders.
MAIN OUTCOME MEASURES
Owing to small numbers of recurrent infections, this analysis focused on time to clearance of colonization in the index case.
Of 223 households, 73 were randomized to education-only, 76 to decolonization without reminders, 74 to decolonization with reminders. There was no significant difference in time to clearance of colonization between the education-only and decolonization groups (log-rank P=.768). In secondary analyses, compliance with decolonization was associated with decreased time to clearance (P=.018).
Total household decolonization did not result in decreased time to clearance of MRSA colonization among adults and children with MRSA skin and soft-tissue infection. However, subjects who were compliant with the protocol had more rapid clearance
To identify risk factors for recurrent methicillin-resistant Staphylococcus aureus (MRSA) colonization.
Prospective cohort study conducted from January 1, 2010, through December 31, 2012.
Five adult and pediatric academic medical centers.
Subjects (ie, index cases) who presented with acute community-onset MRSA skin and soft-tissue infection.
Index cases and all household members performed self-sampling for MRSA colonization every 2 weeks for 6 months. Clearance of colonization was defined as 2 consecutive sampling periods with negative surveillance cultures. Recurrent colonization was defined as any positive MRSA surveillance culture after clearance. Index cases with recurrent MRSA colonization were compared with those without recurrence on the basis of antibiotic exposure, household demographic characteristics, and presence of MRSA colonization in household members.
The study cohort comprised 195 index cases; recurrent MRSA colonization occurred in 85 (43.6%). Median time to recurrence was 53 days (interquartile range, 36–84 days). Treatment with clindamycin was associated with lower risk of recurrence (odds ratio, 0.52; 95% CI, 0.29–0.93). Higher percentage of household members younger than 18 was associated with increased risk of recurrence (odds ratio, 1.01; 95% CI, 1.00–1.02). The association between MRSA colonization in household members and recurrent colonization in index cases did not reach statistical significance in primary analyses.
A large proportion of patients initially presenting with MRSA skin and soft-tissue infection will have recurrent colonization after clearance. The reduced rate of recurrent colonization associated with clindamycin may indicate a unique role for this antibiotic in the treatment of such infection.
Infect. Control Hosp. Epidemiol. 2015;36(7):786–793
To determine the implications of a functional approach to vestibular schwannoma surgery, with facial nerve function prioritised higher than total tumour excision.
A case–control study in a tertiary referral neurotology clinic.
A ‘functional’ surgical group treated after April 2007 (n = 44, mean cerebellopontine angle dimension 27 mm), and an ‘excisional’ surgical group matched for tumour size, treated from 1997 to April 2007 (n = 115).
Facial nerve preservation: 77 per cent House–Brackmann grade I–II in functional group at 12 months, versus 57 per cent grade I–II in excisional group (p = 0.027). Tumour recurrence: 1 per cent in total excision group, 2 per cent in near-total group and 40 per cent in sub-total group.
A functional approach to vestibular schwannoma surgery improves facial nerve preservation outcomes and reduces the requirement for facial nerve rehabilitative interventions. Tumour recurrence rates are low in near-totally excised lesions but significant if only sub-total excision is achieved.
This paper reports on a study of the nucleation phase of thin film growth during pyrolytic deposition by direct-laser writing. A Monte Carlo computer simulation is used to model the initial surface dynamics occurring during the deposition of silicon from silane (SiH4) on strongly binding substrates such as silicon, and on weakly binding substrates such as silicon dioxide (SiO2) and silicon nitride (Si3N4). Results show that for high peak temperatures (≥ 1200 K) and weakly binding substrates, the most probable location for the initiation of thin film growth is radialy displaced from the center of the locally laser-heated region of the surface. At low peak temperatures, thin film nucleation is found to begin at the center of the locally laser-heated surface for all substrates.
This paper reports initial results of an experimental study of the early stages of silicon thin film growth on well prepared (100) c-Si surfaces by pyrolytic deposition from silane (SiH4) during localized laser chemical vapor deposition (LLCVD). The rate of silicon thin film growth during low pressure (< 10 Torr) deposition using tightly focussed laser beams (514.5 nm, ∼ 2.5 μm FWHM) is characterized and is shown to be much slower than expected based on the previously measured silane decomposition rate. Hybrid-heating experiments, in which laser heating induces a slight temperature increase on a uniformly heated substrate in the presence of silane gas, shows that growth is inhibited within the laser irradiation region. This result suggests that a nonpyrolytic mechanism contributes to silicon growth in laser CVD. Possible explanations for this nonpyrolytic growth mechanism are discussed.
The effects of strain and confinement on optical phonons in a Si12Ge4 strained layer superlattice grown by MBE on c-Si (001) were studied as a function of hydrostatic pressure (T = 295 K) using Raman scattering. The change of phonon frequency with pressure, dω/dP, for the principal quasi-confined LO mode in the Ge layers is found to be significantly smaller than that for bulk crystalline Ge because the magnitude of biaxial strain decreases in the Ge layers with added pressure and because the Grüneisen parameter of the confined mode is smaller than that of the Γ-point optical phonon. More generally, it is noted that the magnitude of biaxial strain in many strained layer superlattices initially decreases with the application of hydrostatic pressure, making the structures more stable.
Surface photoabsorption (SPA) has been applied to monitor, in real time, the surface of GaAs(100) during chemical dry etching by a molecular beam of HCl. Changes in the HCl flux to the surface at a constant temperature (840 K) have been used to induce changes in the Ga:As ratio on the surface. These changes in surface stoichiometry have been detected in situ via SPA measurements of the transient fractional change in the reflectance of p-polarized, 488 nm light that is incident onto the surface near the pseudo-Brewster angle. On the basis of results from prior applications of SPA to the study the atomic layer deposition of GaAs, the changes in the SPA signal as a function of the etching parameters can be correlated with changes in the relative surface densities of Ga and As. The findings are confirmed by independent determinations of the changes in surface stoichiometry made by measuring the time-integrated difference in the fluxes of Ga- and As-containing etching products evolved from the surface as a function of the HC1 flux.
We present the results of an investigation of the dependence of the photoluminescence (PL) spectra on preparation conditions, the resulting microstructure, and post-anodization treatment of porous silicon carbide films which were formed from both p and n-type 6H-SiC substrates. Porous samples were prepared by anodic dissolution under different galvanostatic conditions, resulting in different porosities and crystallite sizes. Selected-area electron diffraction patterns taken on similarly prepared porous silicon carbide (PSC) samples confirmed that the films were monocrystalline. Transmission electron microscopy of as-anodized films revealed an isotropie porous network; a dependence of porosity and nanocrystallite size on porous layer formation current density was established. Some PSC samples were passivated using a short, thermal oxidation treatment. The effects of porosity and crystallite size, and of oxide passivation in these PSC films, on PL spectra and intensity were studied using a 365 nm Kr-ion laser as excitation. Under certain conditions, the spectrally integrated PL intensity of a passivated film is more than 450x that for the original bulk SiC substrate. PL spectra are presented, and possible mechanisms are discussed.
We present a study of the infrared reflectance of porous silicon carbide (PSC) formed by the electrochemical dissolution of silicon carbide substrates of both 6H and 4H polytypes. The formation of porous silicon carbide from a 4H-SiC substrate is reported for the first time, as is the reflectance from n-PSC, both as-anodized and passivated. The passivation of PSC has been accomplished using a short thermal oxidation. Fourier transform infrared (FTIR) reflectance spectroscopy is employed ex situ after different stages of the thermal oxidation process. The characteristics of the reststrahlen band normally observed in bulk SiC are altered by anodization; further changes in the reflectance spectra occur following oxidation for different short periods of time. An effective medium theory model which includes air, SiC and SiO2 as component materials is shown to characterize the observed changes in the reflectance spectra after different stages of PSC oxidation.
This paper describes sentinel laboratory surveillance of hepatitis C antibody testing in England. Demographic and test result data were supplemented by follow-up questionnaires sent to the requesting clinician. Between October 2002 and September 2003 almost 75000 anti-HCV tests were performed in eight sentinel centres. More males were tested than females and over half of those tested were aged 25–44 years. Overall 5·7% (3333/58144, range 2·8–7·7%) individuals tested positive. Follow-up questionnaire data showed that 82% (1043/1277) of the positives had injecting drug use reported as the main risk exposure. The majority of negative individuals were undergoing routine screening as recommended for specific patient groups. Most individuals were asymptomatic. Antibody prevalence was estimated to be 34% in current injecting drug users and 42% in former injectors. Comparing positives to routine national surveillance suggests that only 53% (1782/3333) of diagnosed cases were reported. Sentinel laboratory data can provide valuable supplementary data to national surveillance.
Traditional strategies to determine hospital bed surge capacity have relied on cross-sectional hospital census data, which underestimate the true surge capacity in the event of a mass-casualtyincident.
To determine hospital bed surge capacity for the County more accurately using physician and nurse manager assessments for the disposition of all in-patients at multiple facilities.
Overnight- and day-shift nurse managers from each in-patient unit at four different hospitals were approached to make assessments for each patient as to their predicted disposition at 2, 24, and 72 hours post-event in the case of a mass-casualty incident, including transfer to a hypothetical, onsite nursing facility. Physicians at the two academic institutions also were approached for comparison. Age, gender, and admission diagnosis also were recorded for each patient.
A total of 1,741 assessments of 788 patients by 82 nurse managers aabnd 25 physicians from the four institutions were included. Nurse managers assessed approximately one-third of all patients as dischargeable at 24 hours and approximately one-half at 72 hours; one-quarter of the patients were assessed as being transferable to a hypothetical, on-site nursing facility at both time points. Physicians were more likely than werenurse managers to send patients to such a facility or discharge them, but less likely to transfer patients outof the intensive care unit (ICU). Inter-facility variability was explained by differences in the distribution of patient diagnoses.
A large proportion of in-patients can be discharged within 24 and 72 hours in the event of a mass-casualty incident (MCI). Additional beds can be made available if an on-site nursing facility is made available. Both physicians and nurse managers should be included on the team that makes patient dispositions in the event of a MCI.
Fatigue usage monitoring systems (Fums) offer considerable potential for life extension of aircraft parts. In this work the life extension benefits of Fums is assessed by adopting a probabilistic approach. The roles of damage law type and of service usage variability is explored. It is shown by analysis that in the absence of cycle to cycle load interaction effects, load sequence has no effect on eventual life in either linear or non linear damage laws, provided that the function describing the rate of damage growth has separable variables of stress and damage. This condition includes fracture mechanics crack growth laws. Monte Carlo simulations have been conducted of fatigue life distributions in helicopter rotor components. Variability in manoeuvre damage, when summed over a large number of manoeuvres, has little effect on scatter in overall lives. A fixed manoeuvre usage spectrum will result in very small scatter in lives, whereas keeping the usage constant for each helicopter and allowing it to vary between helicopters, produces a significantly increased variability. The influence of load factors on life is also assessed. The extent of possible maintenance credits is discussed together with the use of Bayesian updating to make optimum use of both prior design data and current loads or damage information provided by Fums.
Robert Perry, Department of Neuropathology, Newcastle General Hospital,Ian McKeith, University of Newcastle upon Tyne,Elaine Perry, MRC Neurochemical Pathology Unit, Newcastle General Hospital
Two alternative hypotheses – that there is either a unitary or a multiple neuropathological basis for dementia in diseases associated with Lewy bodies – are considered in relation to Parkinson's disease (PD) and Lewy body dementia (LBD including senile dementia of Lewy body type, SDLT). Densities of limbic (cingulate) cortical Lewy bodies, neocortical Lewy bodies, neocortical plaques, neocortical tangles, Braak staging, and Apo E frequency have been quantified in PD (demented and nondemented), SDLT, and Alzheimer's disease (AD with presenile and senile onset). Of these parameters the mean density of cingulate Lewy bodies is significantly greater in SDLT compared with all PD cases. There is no obvious correlation between Lewy body density and cognitive impairment assessed using a simple test of mental ability, and other measures of mental function in LBD may need to be considered. Since there is no absolute density of limbic Lewy bodies that clearly differentiates SDLT or demented PD cases from all nondemented PD cases, neuropathological criteria may need to incorporate severity of Alzheimer-type pathology as an additional optional factor. Mean neocortical plaque density is significantly lower in SDLT compared with AD cases but it is also significantly higher than in demented and nondemented PD cases, and higher than densities in normals. Even so, neocortical plaque density does not itself differentiate all SDLT cases from the normal. It is likely that the biological basis for dementia or psychoses in LBD, a cardinal feature of which is fluctuating symptomatology, is in part a functional or neurochemical abnormality.
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