2,268 research outputs found

    Serum amyloid P aids complement-mediated immunity to Streptococcus pneumoniae

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    The physiological functions of the acute phase protein serum amyloid P (SAP) component are not well defined, although they are likely to be important, as no natural state of SAP deficiency has been reported. We have investigated the role of SAP for innate immunity to the important human pathogen Streptococcus pneumoniae. Using flow cytometry assays, we show that SAP binds to S. pneumoniae, increases classical pathway–dependent deposition of complement on the bacteria, and improves the efficiency of phagocytosis. As a consequence, in mouse models of infection, mice genetically engineered to be SAP-deficient had an impaired early inflammatory response to S. pneumoniae pneumonia and were unable to control bacterial replication, leading to the rapid development of fatal infection. Complement deposition, phagocytosis, and control of S. pneumoniae pneumonia were all improved by complementation with human SAP. These results demonstrate a novel and physiologically significant role for SAP for complement-mediated immunity against an important bacterial pathogen, and provide further evidence for the importance of the classical complement pathway for innate immunity

    G-BASE field procedures manual : version 1.1

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    The G-BASE project is a long-term systematic geochemical survey that has required a high degree of consistency in its sampling methodologies. This report gives in detail all the project procedures associated with the collection of geochemical samples from the planning phase in the office through to sample reception and reporting of the completed field campaign. The procedures described here should be diligently followed in order to maintain the high levels of quality control the project aspires to. Any changes to procedures are indicated in the latest version of this manual and documented in an updates list in Annex I. In addition to describing all the fieldwork procedures, the recruitment and training of "voluntary" student workers is described along with discussions relating to health and safety issues likely to be encountered during sampling. When describing the methods used by G-BASE in reports or publications, reference should be made to this manual

    Making Black Holes in Supernovae

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    The possibility of making stellar mass black holes in supernovae that otherwise produce viable Type II and Ib supernova explosions is discussed and estimates given of their number in the Milky Way Galaxy. Observational diagnostics of stellar mass black hole formation are reviewed. While the equation of state sets the critical mass, fall back during the explosion is an equally important (and uncertain) element in determining if a black hole is formed. SN 1987A may or may not harbor a black hole, but if the critical mass for neutron stars is 1.5 - 1.6 M\sun, as Brown and Bethe suggest, it probably does. Observations alone do not yet resolve the issue. Reasons for this state of ambiguity are discussed and suggestions given as to how gamma-ray and x-ray observations in the future might help.Comment: 14 pages, uuencoded gzipped postscript, Accepted Nuclear Physics A, Gerry Brown Festschrift contributio

    GSUE: urban geochemical mapping in Great Britain

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    The British Geological Survey is responsible for the national strategic geochemical survey of Great Britain. As part of this programme, the Geochemical Surveys of Urban Environments (GSUE) project was initiated in 1992 and to date, 21 cities have been mapped. Urban sampling is based upon the collection of top (0.05 to 0.20 m) and deeper (0.35 to 0.50 m) soil samples on a 500 m grid across the built environment (1 sample per 0.25 km2). Samples are analysed for c. 46 total element concentrations by X-ray Fluorescence Spectrometry (XRFS), pH and loss on ignition (LOI) as an indicator of organic matter content. The data provide an overview of the urban geochemical signature and because they are collected as part of a national baseline programme, can be readily compared with soils in the rural hinterland to assess the extent of urban contamination. The data are of direct relevance to current UK land use planning, urban regeneration and contaminated land legislative regimes. An overview of the project and applications of the data to human health risk assessment, water quality protection and contaminant source identification are presented

    Temperature dependence of the nuclear symmetry energy

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    We have studied the properties of A=54 and A=64 isobars at temperatures T \leq 2 MeV via Monte Carlo shell model calculations with two different residual interactions. In accord with empirical indications, we find that the symmetry energy coefficient, b_{sym}, is independent of temperature to within 0.6 MeV for T \leq 1 MeV. This is in contrast to a recent suggestion of a 2.5 MeV increase of b_{sym} for this temperature, which would have significantly altered the supernova explosion scenario.Comment: 7 pages, including 2 figures, Caltech preprint MAP-17

    Clyde tributaries : report of urban stream sediment and surface water geochemistry for Glasgow

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    This report presents the results of an urban drainage geochemical survey carried out jointly by the British Geological Survey (BGS) and Glasgow City Council (GCC) during June 2003. 118 stream sediment and 122 surface water samples were collected at a sample density of 1 per 1 km2 from all tributaries draining into the River Clyde within the GCC administrative area. The study was carried out as part of the BGS systematic Geochemical Surveys of Urban Environments (GSUE) programme. Stream sediment and surface water samples underwent analysis for approximately 46 chemical elements including contaminants such as As, Al, Cd, Cu, Cr, Ni, Pb, Se, V and Zn according to standard GSUE procedures. In addition, parameters such as ammonium, asbestos and Hg as well as organic contaminants such as total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAH), poly-chlorinated biphenyls (PCB) and organo-tin compounds were assessed. The aim of the project was to provide an overview of urban drainage geochemistry in Glasgow to link to an on-going sister project, which is investigating the geochemistry of the Clyde estuary. This report presents the initial findings of the Clyde tributaries survey but it is envisaged that the data will be interpreted in more detail as part of a wider Clyde basin study once the Clyde estuary survey is completed

    Fatigue After CriTical illness (FACT): Co-production of a self-management intervention to support people with fatigue after critical illness

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    Purpose: Fatigue is a common and debilitating problem in patients recovering from critical illness. To address a lack of evidence-based interventions for people with fatigue after critical illness, we co-produced a self-management intervention based on self-regulation theory. This article reports the development and initial user testing of the co-produced intervention. Methods: We conducted three workshops with people experiencing fatigue after critical illness, family members, and healthcare professionals to develop a first draft of the FACT intervention, designed in web and electronic document formats. User testing and interviews were conducted with four people with fatigue after critical illness. Modifications were made based on the findings. Results: Participants found FACT acceptable and easy to use, and the content provided useful strategies to manage fatigue. The final draft intervention includes four key topics: (1) about fatigue which discusses the common characteristics of fatigue after critical illness; (2) managing your energy with the 5 Ps (priorities, pacing, planning, permission, position); (3) strategies for everyday life (covering physical activity; home life; leisure and relationships; work, study, and finances; thoughts and feelings; sleep and eating); and (4) goal setting and making plans. All material is presented as written text, videos, and supplementary infographics. FACT includes calls with a facilitator but can also be used independently. Conclusions: FACT is a theory driven intervention co-produced by patient, carer and clinical stakeholders and is based on contemporary available evidence. Its development illustrates the benefits of stakeholder involvement to ensure interventions are informed by user needs. Further testing is needed to establish the feasibility and acceptability of FACT. Implications for clinical practice: The FACT intervention shows promise as a self-management tool for people with fatigue after critical illness. It has the potential to provide education and strategies to patients at the point of discharge and follow-up

    Linking working memory and long-term memory: A computational model of the learning of new words

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    The nonword repetition (NWR) test has been shown to be a good predictor of children’s vocabulary size. NWR performance has been explained using phonological working memory, which is seen as a critical component in the learning of new words. However, no detailed specification of the link between phonological working memory and long-term memory (LTM) has been proposed. In this paper, we present a computational model of children’s vocabulary acquisition (EPAM-VOC) that specifies how phonological working memory and LTM interact. The model learns phoneme sequences, which are stored in LTM and mediate how much information can be held in working memory. The model’s behaviour is compared with that of children in a new study of NWR, conducted in order to ensure the same nonword stimuli and methodology across ages. EPAM-VOC shows a pattern of results similar to that of children: performance is better for shorter nonwords and for wordlike nonwords, and performance improves with age. EPAM-VOC also simulates the superior performance for single consonant nonwords over clustered consonant nonwords found in previous NWR studies. EPAM-VOC provides a simple and elegant computational account of some of the key processes involved in the learning of new words: it specifies how phonological working memory and LTM interact; makes testable predictions; and suggests that developmental changes in NWR performance may reflect differences in the amount of information that has been encoded in LTM rather than developmental changes in working memory capacity. Keywords: EPAM, working memory, long-term memory, nonword repetition, vocabulary acquisition, developmental change

    (93)Nb NMR spin echo spectroscopy in single crystal NbSe(3)

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    International audienceWe report electric field induced phase displacements of the charge density wave (CDW) in a single crystal of NbSe(3) using (93)Nb NMR spin-echo spectroscopy. CDW polarizations in the pinned state induced by unipolar and bipolar pulses are linear and reversible up to at least E = (0.96)E(T). The polarizations have a broad distribution extending up to phase angles of order 60 degrees for electric fields close to threshold. No evidence for polarizations in excess of a CDW wavelength or for a divergence in polarization near ET are observed. The results are consistent with elastic depinning models, provided that the critical regime expected in large systems is not observable

    Competition and coexistence of bond and charge orders in (TMTTF)2AsF6

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    (TMTTF)2AsF6 undergoes two phase transitions upon cooling from 300 K. At Tco=103 K a charge-ordering (CO) occurs, and at Tsp(B=9 T)=11 K the material undergoes a spin-Peierls (SP) transition. Within the intermediate, CO phase, the charge disproportionation ratio is found to be at least 3:1 from carbon-13 NMR 1/T1 measurements on spin-labeled samples. Above Tsp, up to about 3Tsp, 1/T1 is independent of temperature, indicative of low-dimensional magnetic correlations. With the application of about 0.15 GPa pressure, Tsp increases substantially, while Tco is rapidly suppressed, demonstrating that the two orders are competing. The experiments are compared to results obtained from calculations on the 1D extended Peierls-Hubbard model.Comment: 4 pages, 5 figure
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