3,712 research outputs found

    Duration of shedding of respiratory syncytial virus in a community study of Kenyan children

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    Background: Our understanding of the transmission dynamics of respiratory syncytial virus (RSV) infection will be better informed with improved data on the patterns of shedding in cases not limited only to hospital admissions. Methods: In a household study, children testing RSV positive by direct immunofluorescent antibody test (DFA) were enrolled. Nasal washings were scheduled right away, then every three days until day 14, every 7 days until day 28 and every 2 weeks until a maximum of 16 weeks, or until the first DFA negative RSV specimen. The relationship between host factors, illness severity and viral shedding was investigated using Cox regression methods. Results: From 151 families a total of 193 children were enrolled with a median age of 21 months (range 1-164 months), 10% infants and 46% male. The rate of recovery from infection was 0.22/person/day (95% CI 0.19-0.25) equivalent to a mean duration of shedding of 4.5 days (95%CI 4.0-5.3), with a median duration of shedding of 4 days (IQR 2-6, range 1-14). Children with a history of RSV infection had a 40% increased rate of recovery i.e. shorter duration of viral shedding (hazard ratio 1.4, 95% CI 1.01-1.86). The rate of cessation of shedding did not differ significantly between males and females, by severity of infection or by age. Conclusion: We provide evidence of a relationship between the duration of shedding and history of infection, which may have a bearing on the relative role of primary versus re-infections in RSV transmission in the community

    Calcium signals and calpain-dependent necrosis are essential for release of coxsackievirus B from polarized intestinal epithelial cells

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    Coxsackievirus B (CVB), a member of the enterovirus family, targets the polarized epithelial cells lining the intestinal tract early in infection. Although the polarized epithelium functions as a protective barrier, this barrier is likely exploited by CVB to promote viral entry and subsequent egress. Here we show that, in contrast to nonpolarized cells, CVB-infected polarized intestinal Caco-2 cells undergo nonapoptotic necrotic cell death triggered by inositol 1,4,5-trisphosphate receptor-dependent calcium release. We further show that CVB-induced cellular necrosis depends on the Ca 2+-activated protease calpain-2 and that this protease is involved in CVB-induced disruption of the junctional complex and rearrangements of the actin cytoskeleton. Our study illustrates the cell signaling pathways hijacked by CVB, and perhaps other viral pathogens, to promote their replication and spread in polarized cell types. © 2011 Bozym et al.published_or_final_versio

    2,1,3-Benzothiadiazole-5,6-Dicarboxylic Imide - A Versatile Building Block for Additive-and Annealing-Free Processing of Organic Solar Cells with Effi ciencies Exceeding 8%

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    A new photoactive polymer comprising benzo[1,2‐b:3,4‐bâ€Č:5,6‐dâ€Č]trithiophene and 2,1,3‐benzothiadiazole‐5,6‐dicarboxylic imide is reported. The synthetic design allows for alkyl chains to be introduced on both electron‐rich and electron‐deficient components, which in turn allows for rapid optimization of the alkyl chain substitution pattern. Consequently, the optimized polymer shows a maximum efficiency of 8.3% in organic photovoltaic devices processed in a commercially viable fashion without solvent additives, annealing, or device engineering

    Sodium and Potassium Ion Selective Conjugated Polymers for Optical Ion Detection in Solution and Solid State

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    EPSRC. Grant Number: EP/G037515/1; EC FP7 Project SC2. Grant Number: 610115; EC FP7 Project ArtESun. Grant Number: 604397; EC FP7 POLYMED. Grant Number: 61253

    Measuring the effect of enhanced cleaning in a UK hospital : a prospective cross-over study

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    Increasing hospital-acquired infections have generated much attention over the last decade. There is evidence that hygienic cleaning has a role in the control of hospital-acquired infections. This study aimed to evaluate the potential impact of one additional cleaner by using microbiological standards based on aerobic colony counts and the presence of Staphylococcus aureus including meticillin-resistant S. aureus. We introduced an additional cleaner into two matched wards from Monday to Friday, with each ward receiving enhanced cleaning for six months in a cross-over design. Ten hand-touch sites on both wards were screened weekly using standardised methods and patients were monitored for meticillin-resistant S. aureus infection throughout the year-long study. Patient and environmental meticillin-resistant S. aureus isolates were characterised using molecular methods in order to investigate temporal and clonal relationships. Enhanced cleaning was associated with a 32.5% reduction in levels of microbial contamination at handtouch sites when wards received enhanced cleaning (P < 0.0001: 95% CI 20.2%, 42.9%). Near-patient sites (lockers, overbed tables and beds) were more frequently contaminated with meticillin-resistant S. aureus/S. aureus than sites further from the patient (P = 0.065). Genotyping identified indistinguishable strains from both handtouch sites and patients. There was a 26.6% reduction in new meticillin-resistant S. aureus infections on the wards receiving extra cleaning, despite higher meticillin-resistant S. aureus patient-days and bed occupancy rates during enhanced cleaning periods (P = 0.032: 95% CI 7.7%, 92.3%). Adjusting for meticillin-resistant S. aureus patient-days and based upon nine new meticillin-resistant S. aureus infections seen during routine cleaning, we expected 13 new infections during enhanced cleaning periods rather than the four that actually occurred. Clusters of new meticillin-resistant S. aureus infections were identified 2 to 4 weeks after the cleaner left both wards. Enhanced cleaning saved the hospital ÂŁ30,000 to ÂŁ70,000.Introducing one extra cleaner produced a measurable effect on the clinical environment, with apparent benefit to patients regarding meticillin-resistant S. aureus infection. Molecular epidemiological methods supported the possibility that patients acquired meticillin-resistant S. aureus from environmental sources. These findings suggest that additional research is warranted to further clarify the environmental, clinical and economic impact of enhanced hygienic cleaning as a component in the control of hospital-acquired infection

    New evidence on the tool-assisted hunting exhibited by chimpanzees (Pan troglodytes verus) in a savannah habitat at Fongoli, Sénégal

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    For anthropologists, meat eating by primates like chimpanzees (Pan troglodytes) warrants examination given the emphasis on hunting in human evolutionary history. As referential models, apes provide insight into the evolution of hominin hunting, given their phylogenetic relatedness and challenges reconstructing extinct hominin behaviour from palaeoanthropological evidence. Among chimpanzees, adult males are usually the main hunters, capturing vertebrate prey by hand. Savannah chimpanzees (P. t. verus) at Fongoli, Sénégal are the only known nonhuman population that systematically hunts vertebrate prey with tools, making them an important source for hypotheses of early hominin behaviour based on analogy. Here, we test the hypothesis that sex and age patterns in tool-assisted hunting (n=308 cases) at Fongoli occur and differ from chimpanzees elsewhere, and we compare tool-assisted hunting to the overall hunting pattern. Males accounted for 70% of all captures but hunted with tools less than expected based on their representation on hunting days. Females accounted for most toolassisted hunting. We propose that social tolerance at Fongoli along with the tool-assisted hunting method, permits individuals other than adult males to capture and retain control of prey, which is uncommon for chimpanzees. We assert that tool-assisted hunting could have similarly been important for early hominins

    Accreting Neutron Stars in Low-Mass X-Ray Binary Systems

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    Using the Rossi X-ray Timing Explorer (RossiXTE), astronomers have discovered that disk-accreting neutron stars with weak magnetic fields produce three distinct types of high-frequency X-ray oscillations. These oscillations are powered by release of the binding energy of matter falling into the strong gravitational field of the star or by the sudden nuclear burning of matter that has accumulated in the outermost layers of the star. The frequencies of the oscillations reflect the orbital frequencies of gas deep in the gravitational field of the star and/or the spin frequency of the star. These oscillations can therefore be used to explore fundamental physics, such as strong-field gravity and the properties of matter under extreme conditions, and important astrophysical questions, such as the formation and evolution of millisecond pulsars. Observations using RossiXTE have shown that some two dozen neutron stars in low-mass X-ray binary systems have the spin rates and magnetic fields required to become millisecond radio-emitting pulsars when accretion ceases, but that few have spin rates above about 600 Hz. The properties of these stars show that the paucity of spin rates greater than 600 Hz is due in part to the magnetic braking component of the accretion torque and to the limited amount of angular momentum that can be accreted in such systems. Further study will show whether braking by gravitational radiation is also a factor. Analysis of the kilohertz oscillations has provided the first evidence for the existence of the innermost stable circular orbit around dense relativistic stars that is predicted by strong-field general relativity. It has also greatly narrowed the possible descriptions of ultradense matter.Comment: 22 pages, 7 figures, updated list of sources and references, to appear in "Short-period Binary Stars: Observation, Analyses, and Results", eds. E.F. Milone, D.A. Leahy, and D. Hobill (Dordrecht: Springer, http://www.springerlink.com

    Synthesis of novel thieno[3,2-b]thienobis(silolothiophene) based low bandgap polymers for organic photovoltaics

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    Thieno[3,2-b]thienobis(silolothiophene), a new electron rich hexacyclic monomer has been synthesized and incorporated into three novel donor–acceptor low-bandgap polymers. By carefully choosing the acceptor co-monomer, the energy levels of the polymers could be modulated and high power conversion efficiencies of 5.52% were reached in OPV devices

    BCAA catabolism in brown fat controls energy homeostasis through SLC25A44.

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    Branched-chain amino acid (BCAA; valine, leucine and isoleucine) supplementation is often beneficial to energy expenditure; however, increased circulating&nbsp;levels of BCAA are linked to obesity and diabetes. The mechanisms of this paradox remain unclear. Here we report that, on cold exposure, brown adipose tissue (BAT) actively utilizes BCAA in the mitochondria for thermogenesis and promotes systemic BCAA clearance in mice and humans. In turn, a BAT-specific defect in BCAA catabolism attenuates systemic BCAA clearance, BAT fuel oxidation and thermogenesis, leading to diet-induced obesity and glucose intolerance. Mechanistically, active BCAA catabolism in BAT is mediated by SLC25A44, which transports BCAAs into mitochondria. Our results suggest that BAT serves as a key metabolic filter that controls BCAA clearance via SLC25A44, thereby contributing to the improvement of metabolic health
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