1,185 research outputs found

    THERMODYNAMIC SIMULATION OF BIOMASS GAS STEAM REFORMING FOR A SOLID OXIDE FUEL CELL (SOFC) SYSTEM

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    This paper presents a methodology to simulate a small-scale fuel cell system for power generation using biomass gas as fuel. The methodology encompasses the thermodynamic and electrochemical aspects of a solid oxide fuel cell (SOFC), as well as solves the problem of chemical equilibrium in complex systems. In this case the complex system is the internal reforming of biomass gas to produce hydrogen. The fuel cell input variables are: operational voltage, cell power output, composition of the biomass gas reforming, thermodynamic efficiency, electrochemical efficiency, practical efficiency, the First and Second law efficiencies for the whole system. The chemical compositions, molar flows and temperatures are presented to each point of the system as well as the exergetic efficiency. For a molar water/carbon ratio of 2, the thermodynamic simulation of the biomass gas reforming indicates the maximum hydrogen production at a temperature of 1070 K, which can vary as a function of the biomass gas composition. The comparison with the efficiency of simple gas turbine cycle and regenerative gas turbine cycle shows the superiority of SOFC for the considered electrical power range.26474575

    Rpgrip1 is required for rod outer segment development and ciliary protein trafficking in zebrafish

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    The authors would like to thank the Royal Society of London, the National Eye Research Centre, the Visual Research Trust, Fight for Sight, the W.H. Ross Foundation, the Rosetrees Trust, and the Glasgow Children’s Hospital Charity for supporting this work. This work was also supported by the Deanship of Scientific Research at King Saud University for funding this research (Research Project) grant number ‘RGP – VPP – 219’.Mutations in the RPGR-interacting protein 1 (RPGRIP1) gene cause recessive Leber congenital amaurosis (LCA), juvenile retinitis pigmentosa (RP) and cone-rod dystrophy. RPGRIP1 interacts with other retinal disease-causing proteins and has been proposed to have a role in ciliary protein transport; however, its function remains elusive. Here, we describe a new zebrafish model carrying a nonsense mutation in the rpgrip1 gene. Rpgrip1homozygous mutants do not form rod outer segments and display mislocalization of rhodopsin, suggesting a role for RPGRIP1 in rhodopsin-bearing vesicle trafficking. Furthermore, Rab8, the key regulator of rhodopsin ciliary trafficking, was mislocalized in photoreceptor cells of rpgrip1 mutants. The degeneration of rod cells is early onset, followed by the death of cone cells. These phenotypes are similar to that observed in LCA and juvenile RP patients. Our data indicate RPGRIP1 is necessary for rod outer segment development through regulating ciliary protein trafficking. The rpgrip1 mutant zebrafish may provide a platform for developing therapeutic treatments for RP patients.Publisher PDFPeer reviewe

    'Let's make lots of money': the determinants of performance in the recorded music sector

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    This research analyzes the performance of 467 record labels in eight European countries over a period of 13 years (2003-2015). The main goal is to explain a relative measure of profitability in terms of observed variables, although the nature of the dataset also allows us to include non-observed firm and country effects. To this end alternative models are estimated and three main research questions are tested, namely: (1) the effect of the dual structure of the recorded music market, in which a competitive segment and an oligopoly coexist; (2) the extent and source of the volatility of profits in record labels; and (3) the nonlinear impact of size on performance

    Whole-body MRI for staging and interim response monitoring in paediatric and adolescent Hodgkin's lymphoma: a comparison with multi-modality reference standard including 18F-FDG-PET-CT

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    Objectives: To prospectively investigate concordance between whole-body MRI (WB-MRI) and a composite reference standard for initial staging and interim response evaluation in paediatric and adolescent Hodgkin’s lymphoma. // Methods: Fifty patients (32 male, age range 6–19 years) underwent WB-MRI and standard investigations, including 18F-FDG-PET-CT at diagnosis and following 2–3 chemotherapy cycles. Two radiologists in consensus interpreted WB-MRI using prespecified definitions of disease positivity. A third radiologist reviewed a subset of staging WB-MRIs (n = 38) separately to test for interobserver agreement. A multidisciplinary team derived a primary reference standard using all available imaging/clinical investigations. Subsequently, a second multidisciplinary panel rereviewed all imaging with long-term follow-up data to derive an enhanced reference standard. Interobserver agreement for WB-MRI reads was tested using kappa statistics. Concordance for correct classification of all disease sites, true positive rate (TPR), false positive rate (FPR) and kappa for staging/response agreement were calculated for WB-MRI. // Results: There was discordance for full stage in 74% (95% CI 61.9–83.9%) and 44% (32.0–56.6%) of patients against the primary and enhanced reference standards, respectively. Against the enhanced reference standard, the WB-MRI TPR, FPR and kappa were 91%, 1% and 0.93 (0.90–0.96) for nodal disease and 79%, < 1% and 0.86 (0.77–0.95) for extra-nodal disease. WB-MRI response classification was correct in 25/38 evaluable patients (66%), underestimating response in 26% (kappa 0.30, 95% CI 0.04–0.57). There was a good agreement for nodal (kappa 0.78, 95% CI 0.73–0.84) and extra-nodal staging (kappa 0.60, 95% CI 0.41–0.78) between WB-MRI reads. // Conclusions: WB-MRI has reasonable accuracy for nodal and extra-nodal staging but is discordant with standard imaging in a substantial minority of patients, and tends to underestimate disease response

    Neuronal circuitry for pain processing in the dorsal horn

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    Neurons in the spinal dorsal horn process sensory information, which is then transmitted to several brain regions, including those responsible for pain perception. The dorsal horn provides numerous potential targets for the development of novel analgesics and is thought to undergo changes that contribute to the exaggerated pain felt after nerve injury and inflammation. Despite its obvious importance, we still know little about the neuronal circuits that process sensory information, mainly because of the heterogeneity of the various neuronal components that make up these circuits. Recent studies have begun to shed light on the neuronal organization and circuitry of this complex region

    BMP signals and the transcriptional repressor BLIMP1 during germline segregation in the mammalian embryo

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    Molecular factors and tissue compartments involved in the foundation of the mammalian germline have been mainly described in the mouse so far. To find mechanisms applicable to mammals in general, we analyzed temporal and spatial expression patterns of the transcriptional repressor BLIMP1 (also known as PRDM1) and the signaling molecules BMP2 and BMP4 in perigastrulation and early neurulation embryos of the rabbit using whole-mount in situ hybridization and high-resolution light microscopy. Both BMP2 and BMP4 are expressed in annular domains at the boundary of the embryonic disc, which—in contrast to the situation in the mouse—partly belong to intraembryonic tissues. While BMP2 expression begins at (pregastrulation) stage 1 in the hypoblast, BMP4 expression commences—distinctly delayed compared to the mouse—diffusely at (pregastrulation) stage 2; from stage 3 onwards, BMP4 is expressed peripherally in hypoblast and epiblast and in the mesoderm at the posterior pole of the embryonic disc. BLIMP1 expression begins throughout the hypoblast at stage 1 and emerges in single primordial germ cell (PGC) precursors in the posterior epiblast at stage 2 and then in single mesoderm cells at positions identical to those identified by PGC-specific antibodies. These expression patterns suggest that function and chronology of factors involved in germline segregation are similar in mouse and rabbit, but higher temporal and spatial resolution offered by the rabbit demonstrates a variable role of bone morphogenetic proteins and makes “blimping” a candidate case for lateral inhibition without the need for an allantoic germ cell niche

    B Lymphocyte intestinal homing in inflammatory bowel disease

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    <p>Abstract</p> <p>Background</p> <p>Inflammatory bowel disease (IBD) is thought to be due to an abnormal interaction between the host immune system and commensal microflora. Within the intestinal immune system, B cells produce physiologically natural antibodies but pathologically atypical anti-neutrophil antibodies (xANCAs) are frequently observed in patients with IBD. The objective is to investigate the localisation of immunoglobulin-producing cells (IPCs) in samples of inflamed intestinal tissue taken from patients with IBD, and their possible relationship with clinical features.</p> <p>Methods</p> <p>The IPCs in small intestinal, colonic and rectal biopsy specimens of patients with IBD were analysed by means of immunofluorescence using polyclonal rabbit anti-human Ig and goat anti-human IgM. The B cell phenotype of the IPC-positive samples was assessed using monoclonal antibodies specific for CD79, CD20, CD23, CD21, CD5, λ and Îș chains. Statistical correlations were sought between the histological findings and clinical expression.</p> <p>Results</p> <p>The study involved 96 patients (64 with ulcerative colitis and 32 with Crohn's disease). Two different patterns of B lymphocyte infiltrates were found in the intestinal tissue: one was characterised by a strong to moderate stromal localisation of small IgM<sup>+</sup>/CD79<sup>+</sup>/CD20<sup>-</sup>/CD21<sup>-</sup>/CD23<sup>-</sup>/CD5<sup>± </sup>IPCs (42.7% of cases); in the other (57.3%) no such small IPCs were detected in stromal or epithelial tissues. <it>IPCs </it>were significantly less frequent in the patients with Crohn's disease than in those with ulcerative colitis (p = 0.004).</p> <p>Conclusion</p> <p>Our findings suggest that different immunopathogenetic pathways underlie chronic intestinal inflammation with different clinical expressions. The presence of small B lymphocytes resembling B-1 cells also seemed to be negatively associated with Crohn's disease. It can therefore be inferred that the gut contains an alternative population of B cells that have a regulatory function.</p

    Measurement and Interpretation of Fermion-Pair Production at LEP energies above the Z Resonance

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    This paper presents DELPHI measurements and interpretations of cross-sections, forward-backward asymmetries, and angular distributions, for the e+e- -> ffbar process for centre-of-mass energies above the Z resonance, from sqrt(s) ~ 130 - 207 GeV at the LEP collider. The measurements are consistent with the predictions of the Standard Model and are used to study a variety of models including the S-Matrix ansatz for e+e- -> ffbar scattering and several models which include physics beyond the Standard Model: the exchange of Z' bosons, contact interactions between fermions, the exchange of gravitons in large extra dimensions and the exchange of sneutrino in R-parity violating supersymmetry.Comment: 79 pages, 16 figures, Accepted by Eur. Phys. J.
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