699 research outputs found

    Preclinical detection of infectivity and disease-specific PrP in blood throughout the incubation period of prion disease.

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    Variant Creutzfeldt-Jakob disease (vCJD) is a fatal neurodegenerative disorder characterised by accumulation of pathological isoforms of the prion protein, PrP. Although cases of clinical vCJD are rare, there is evidence there may be tens of thousands of infectious carriers in the United Kingdom alone. This raises concern about the potential for perpetuation of infection via medical procedures, in particular transfusion of contaminated blood products. Accurate biochemical detection of prion infection is crucial to mitigate risk and we have previously reported a blood assay for vCJD. This assay is sensitive for abnormal PrP conformers at the earliest stages of preclinical prion disease in mice and precedes the maximum infectious titre in blood. Not only does this support the possibility of screening asymptomatic individuals, it will also facilitate the elucidation of the complex relationship that exists between the ensemble of abnormal PrP conformers present in blood and the relationship to infectivity

    Childhood abuse and the content of delusions

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    Original article can be found at: http://www.sciencedirect.com/science/journal/01452134 Copyright Elsevier Ltd.We aimed to investigate possible associations between histories of childhood abuse and the content of delusions for individuals with psychotic disorders. 39 participants with a psychotic disorder including one or more delusional beliefs successfully completed structured interviews about childhood trauma, delusional beliefs and associated anomalous perceptual experiences including hallucinations. The presence of hallucinations was predicted by greater physical abuse. Greater abuse in general was associated with delusions involving ‘special abilities’ (grandiosity) and, at trend levels, with those involving ‘defective self’. Though preliminary, these results suggest that further investigation is warranted. The presence and nature of abuse may be relevant to delusional presentations and should form an essential part of clinical assessment of psychotic disorder.Peer reviewe

    Warm Absorbers and Outflows in the Seyfert-1 Galaxy NGC 4051

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    We present both phenomenological and more physical photoionization models of the Chandra HETG spectra of the Seyfert-1 AGN NGC 4051. We detect 40 absorption and emission lines, encompassing highly ionized charge states from O, Ne, Mg, Si, S and the Fe L-shell and K-shell. Two independent photoionization packages, XSTAR and Cloudy, were both used to self-consistently model the continuum and line spectra. These fits detected three absorbing regions in this system with densities ranging from 10^{10} to 10^{11} cm^{-3}. In particular, our XSTAR models require three components that have ionization parameters of log \xi = 4.5, 3.3, & 1.0, and are located within the BLR at 70, 300, and 13,000 R_g, respectively, assuming a constant wind density. Larger radii are inferred for density profiles which decline with radius. The Cloudy models give a similar set of parameters with ionization parameters of log \xi = 5.0, 3.6, & 2.2 located at 40, 200, and 3,300 R_g. We demonstrate that these regions are out-flowing from the system, and carry a small fraction of material out of the system relative to the implied mass accretion rate. The data suggest that magnetic fields may be an important driving mechanism.Comment: 21 pages, 11 Figures, Accepted to Ap

    The Identification and Synthesis of Lead Apatite Minerals Formed in Lead Water Pipes

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    Phosphate is added to drinking water in the UK to minimise the release of lead from lead water pipes. The phosphate encourages the formation of insoluble lead apatites on the walls of the pipe. Hydroxylpyromorphite Pb5(PO4)3OH is the lead apatite that is most often used to model lead levels in tap water; however, its presence has not been confirmed. Our aims were to identify the lead pipe apatite and synthesise it. The synthetic mineral would then be used in future solubility studies to produce better predictions of lead levels in tap water. XRD and FTIR were used to characterise the minerals on a range of lead pipes. Pyromorphite and hydroxylpyromorphite were absent and instead a range of mixed calcium lead apatites were present. For every five lead ions in the general formula Pb5(PO4)3X between one and two ions were replaced with calcium and there was evidence of substitution of by either or . Calcium lead apatites with similar unit cell dimensions to those found on lead water pipes were then synthesised. The calcium : lead ratio in these reaction mixtures was in excess of 500 : 1 and the resulting crystals were shown by TEM to be nanosized rods and flakes. The synthetic apatites that most closely resembled the unit cell dimensions of the apatites on lead water pipes were shown to be Pb3.4Ca1.3(PO4)3Cl0.03OH0.97, Pb3.6Ca1.2(PO4)3Cl0.07OH0.93, and Pb3.6Ca1.2(PO4)3Cl0.27OH0.73

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