1,761 research outputs found

    Nod1 signaling overcomes resistance of S. pneumoniae to opsonophagocytic killing

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    Airway infection by the Gram-positive pathogen Streptococcus pneumoniae (Sp) leads to recruitment of neutrophils but limited bacterial killing by these cells. Co-colonization by Sp and a Gram-negative species, Haemophilus influenzae (Hi), provides sufficient stimulus to induce neutrophil and complement-mediated clearance of Sp from the mucosal surface in a murine model. Products from Hi, but not Sp, also promote killing of Sp by ex vivo neutrophil-enriched peritoneal exudate cells. Here we identify the stimulus from Hi as its peptidoglycan. Enhancement of opsonophagocytic killing was facilitated by signaling through nucleotide-binding oligomerization domain-1 (Nod1), which is involved in recognition of Îł-D-glutamyl-meso-diaminopimelic acid (meso-DAP) contained in cell walls of Hi but not Sp. Neutrophils from mice treated with Hi or compounds containing meso-DAP, including synthetic peptidoglycan fragments, showed increased Sp killing in a Nod1-dependent manner. Moreover, Nod1-/- mice showed reduced Hi-induced clearance of Sp during co-colonization. These observations offer insight into mechanisms of microbial competition and demonstrate the importance of Nod1 in neutrophil-mediated clearance of bacteria in vivo

    Silicon photomultiplier arrays - a novel photon detector for a high resolution tracker produced at FBK-irst, Italy

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    A silicon photomultiplier (SiPM) array has been developed at FBK-irst having 32 channels and a dimension of 8.0 x 1.1 mm^2. Each 250 um wide channel is subdivided into 5 x 22 rectangularly arranged pixels. These sensors are developed to read out a modular high resolution scintillating fiber tracker. Key properties like breakdown voltage, gain and photon detection efficiency (PDE) are found to be homogeneous over all 32 channels of an SiPM array. This could make scintillating fiber trackers with SiPM array readout a promising alternative to available tracker technologies, if noise properties and the PDE are improved

    Phenotypic and functional characterization of adult brain neuropoiesis

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    The modern concept of neurogenesis in the adult brain is predicated on the premise that multipotent glial cells give rise to new neurons throughout life. Although extensive evidence exists indicating that this is the case, the transition from glial to neuronal phenotype remains poorly understood. A unique monolayer cell-culture system was developed to induce, expose, and recapitulate the entire developmental series of events of subventricular zone (SVZ) neurogenesis. We show here, using immunophentoypic, ultrastructural, electrophysiological, and time-lapse analyses, that SVZ-derived glial fibrillary acidic protein(low)/A2B5(+)/nestin(+) candidate founder cells undergo metamorphosis to eventually generate large numbers of fully differentiated interneuron phenotypes. A model of postnatal neurogenesis is considered in light of known embryonic events and reveals a limited developmental potential of SVZ stem/progenitor cells, whereby ancestral cells in both embryonic and postnatal/adult settings give rise to glia and GABAergic interneurons

    SUpporting wellbeing through PEeR-Befriending (SUPERB) feasibility trial: fidelity of peer-befriending for people with aphasia.

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    Objective To evaluate systematically the fidelity of a peer-befriending intervention for people with aphasia. Design SUpporting wellbeing through Peer-befriending (SUPERB) was a feasibility randomised controlled trial comparing usual care to usual care +peer-befriending. This paper reports on the fidelity of all intervention aspects (training and supervision of providers/befrienders; intervention visits) which was evaluated across all areas of the Behaviour Change Consortium framework. Setting Community. Participants People with aphasia early poststroke and low levels of distress, randomised to the intervention arm of the trial (n=28); 10 peer-befrienders at least 1-year poststroke. Intervention Peer-befrienders were trained (4–6 hours); and received regular supervision (monthly group while actively befriending, and one-to-one as and when needed) in order to provide six 1-hour peer-befriending visits over 3 months. Main measures Metrics included number and length of training, supervision sessions and visits. All training and supervision sessions and one (of six) visits per pair were rated against fidelity checklists and evaluated for inter-rater and intrarater reliability (Gwets AC1 agreement coefficient). Per-cent adherence to protocol was evaluated. Results All peer-befrienders received 4–6 hours training over 2–3 days as intended. There were 25 group supervision sessions with a median number attended of 14 (IQR=8–18). Twenty-six participants agreed (92.8%) to the intervention and 21 (80.8%) received all six visits (median visit length 60 min). Adherence was high for training (91.7%–100%) and supervision (83%–100%) and moderate-to-high for befriending visits (66.7%–100%). Where calculable, inter-rater and intrarater reliability was high for training and supervision (Gwets AC1 >0.90) and moderate-to-high for intervention visits (Gwets AC1 0.44–1.0). Conclusion Planning of fidelity processes at the outset of the trial and monitoring throughout was feasible and ensured good-to-high fidelity for this peer-befriending intervention. The results permit confidence in other findings from the SUPERB trial

    A Scintillating Fiber Tracker With SiPM Readout

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    We present a prototype for the first tracking detector consisting of 250 micron thin scintillating fibers and silicon photomultiplier (SiPM) arrays. The detector has a modular design, each module consists of a mechanical support structure of 10mm Rohacell foam between two 100 micron thin carbon fiber skins. Five layers of scintillating fibers are glued to both top and bottom of the support structure. SiPM arrays with a channel pitch of 250 micron are placed in front of the fibers. We show the results of the first module prototype using multiclad fibers of types Bicron BCF-20 and Kuraray SCSF-81M that were read out by novel 32-channel SiPM arrays from FBK-irst/INFN Perugia as well as 32-channel SiPM arrays produced by Hamamatsu. A spatial resolution of 88 micron +/- 6 micron at an average yield of 10 detected photons per minimal ionizig particle has been achieved.Comment: 5 pages, 7 figures, submitted as proceedings to the 11th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD08

    A Randomised Trial of Social Support Group Intervention for People with Aphasia: A Novel Application of Virtual Reality

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    About a third of strokes cause aphasia, or language loss, with profound consequences for the person’s social participation and quality of life. These problems may be mitigated by group social support. But this intervention is not available to all individuals. This study investigated whether it is feasible to deliver group social support to people with aphasia via a multi-user, virtual reality platform. It also explored the indicative effects of intervention and the costs. Intervention aimed to promote wellbeing and communicative success. It enabled participants to form new social connections and share experiences of living with aphasia. It comprised 14 sessions delivered over 6 months and was led by community based co-ordinators and volunteers. Feasibility measures comprised: recruitment and retention rates, compliance with intervention and assessment of treatment fidelity. Effects of intervention were explored using a waitlist randomised controlled design, with outcome measures of wellbeing, communication, social connectedness and quality of life. Two intervention groups were randomised to an immediate condition and two were randomised to a delayed condition. The main analysis explored scores on the measures between two time points, between which those in the immediate condition had received intervention, but those in the delayed group had not (yet). A comprehensive approach to economic data collection ensured that all costs of treatment delivery were recorded. Feasibility findings showed that the recruitment target was met (N = 34) and 85.3% (29/34) of participants completed intervention. All groups ran the 14 sessions as planned, and participants attended a mean of 11.4 sessions (s.d. 2.8), which was 81.6% of the intended dose. Fidelity checking showed minimal drift from the manualised intervention. No significant change was observed on any of the outcome measures, although the study was not powered to detect these. Costs varied across the four groups, from £7,483 - £12,562 British Pounds Sterling (10,972−10,972 - 18,419 US dollars), depending on travel costs, the relative contributions of volunteers and the number of hardware loans that were needed. The results suggest that a larger trial of remote group support, using virtual reality, would be merited. However the treatment content and regime, and the selection of outcome measures should be reviewed before conducting the trial

    Overcoming the Challenges Associated with Image-based Mapping of Small Bodies in Preparation for the OSIRIS-REx Mission to (101955) Bennu

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    The OSIRIS-REx Asteroid Sample Return Mission is the third mission in NASA's New Frontiers Program and is the first U.S. mission to return samples from an asteroid to Earth. The most important decision ahead of the OSIRIS-REx team is the selection of a prime sample-site on the surface of asteroid (101955) Bennu. Mission success hinges on identifying a site that is safe and has regolith that can readily be ingested by the spacecraft's sampling mechanism. To inform this mission-critical decision, the surface of Bennu is mapped using the OSIRIS-REx Camera Suite and the images are used to develop several foundational data products. Acquiring the necessary inputs to these data products requires observational strategies that are defined specifically to overcome the challenges associated with mapping a small irregular body. We present these strategies in the context of assessing candidate sample-sites at Bennu according to a framework of decisions regarding the relative safety, sampleability, and scientific value across the asteroid's surface. To create data products that aid these assessments, we describe the best practices developed by the OSIRIS-REx team for image-based mapping of irregular small bodies. We emphasize the importance of using 3D shape models and the ability to work in body-fixed rectangular coordinates when dealing with planetary surfaces that cannot be uniquely addressed by body-fixed latitude and longitude.Comment: 31 pages, 10 figures, 2 table

    Dominion cartoon satire as trench culture narratives: complaints, endurance and stoicism

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    Although Dominion soldiers’ Great War field publications are relatively well known, the way troops created cartoon multi-panel formats in some of them has been neglected as a record of satirical social observation. Visual narrative humour provides a ‘bottom-up’ perspective for journalistic observations that in many cases capture the spirit of the army in terms of stoicism, buoyed by a culture of internal complaints. Troop concerns expressed in the early comic strips of Australians, Canadians, New Zealanders and British were similar. They shared a collective editorial purpose of morale boosting among the ranks through the use of everyday narratives that elevated the anti-heroism of the citizen soldier, portrayed as a transnational everyman in the service of empire. The regenerative value of disparagement humour provided a redefinition of courage as the very act of endurance on the Western Front
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