20,240 research outputs found

    Epigenetic silencing of SOCS3 expression contributes to fibrosis in Crohn’s disease

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    Identified risk polymorphisms affecting the Jak-STAT3 pathway in patients with Crohn’s disease could affect TGF-β1 and collagen I expression and in the pathway’s negative regulator, SOCS3. Genetic factors, however, account for only ~25% of disease. Epigenetic events also shape gene expression. Recent experiments showed that autocrine IL-6 production in mesenchymal cells, subepithelial myofibroblasts (SEMF) and muscle cells, of patients with fibrostenotic Crohn’s disease causes sustained Jak-STAT3 activity, excess TGF-β1 and Collagen I production and fibrosis. SOCS3 paradoxically decreased in these cells. We now identify epigenetic mechanisms that silence SOCS3 expression in SEMF of patients with fibrostenotic Crohn’s disease. In a previous experiment, using isolated SEMF of normal ileum and affected ileum from patients with each Crohn’s phenotype, inflammatory (Montreal B1), fibrostenotic (B2) and penetrating (B3), we confirmed decreased SOCS3 protein levels were unique to B2 patients. Expression of miR-19b increased in SEMF of affected ileum. SOCS3 transcriptional activity decreased after transfection of miR-19b mimic and increased when antagomiR-19b was expressed. Epigenetic silencing of SOCS3 in ileal SEMF of patients with fibrostenotic Crohn’s disease occurs by increased miR-19b mediated inhibition of SOCS3

    Electrically tunable selective reflection of light from ultraviolet to visible and infrared by heliconical cholesterics

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    Cholesteric liquid crystals with helicoidal molecular architecture are known for their ability to selectively reflect light with the wavelength that is determined by the periodicity of molecular orientations. Here we demonstrate that by using a cholesteric with oblique helicoidal(heliconical) structure, as opposed to the classic right-angle helicoid, one can vary the wavelength of selectively reflected light in a broad spectral range, from ultraviolet to visible and infrared (360-1520 nm for the same chemical composition) by simply adjusting the electric field applied parallel to the helicoidal axis. The effect exists in a wide temperature range (including the room temperatures) and thus can enable many applications that require dynamically controlled transmission and reflection of electromagnetic waves, from energy-saving smart windows to tunable organic lasers, reflective color display, and transparent see-through displays.Comment: 11 pages, 5figure

    On the Universality of Mesoscience: Science of 'the in-between'

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    The universality of mesoscales, ranging between elemental particles and the universe, is discussed here by reviewing widely disparate fields and presenting four cases, at differing hierarchical levels, from chemistry, chemical engineering, meteorology, through to astronomy. An underpinning concept, "Compromise in competition", is highlighted between various dominant, but competing mechanisms, and is identified here to be the universal origin of complexity and diversity in such examples. We therefore advance this as a key underlying principle of an emerging science -- Mesoscience.Comment: 8 pages, 1 figur

    The Removal of Artificially Generated Polarization in SHARP Maps

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    We characterize the problem of artificial polarization for the Submillimeter High Angular Resolution Polarimeter (SHARP) through the use of simulated data and observations made at the Caltech Submillimeter Observatory (CSO). These erroneous, artificial polarization signals are introduced into the data through misalignments in the bolometer sub-arrays plus pointing drifts present during the data-taking procedure. An algorithm is outlined here to address this problem and correct for it, provided that one can measure the degree of the sub-array misalignments and telescope pointing drifts. Tests involving simulated sources of Gaussian intensity profile indicate that the level of introduced artificial polarization is highly dependent upon the angular size of the source. Despite this, the correction algorithm is effective at removing up to 60% of the artificial polarization during these tests. The analysis of Jupiter data taken in January 2006 and February 2007 indicates a mean polarization of 1.44%+/-0.04% and 0.95%+/-0.09%, respectively. The application of the correction algorithm yields mean reductions in the polarization of approximately 0.15% and 0.03% for the 2006 and 2007 data sets, respectively.Comment: 19 pages, 7 figure

    Stress and Emotion Classification Using Jitter and Shimmer Features

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    In this paper, we evaluate the use of appended jitter and shimmer speech features for the classification of human speaking styles and of animal vocalization arousal levels. Jitter and shimmer features are extracted from the fundamental frequency contour and added to baseline spectral features, specifically Mel-frequency cepstral coefficients (MFCCs) for human speech and Greenwood function cepstral coefficients (GFCCs) for animal vocalizations. Hidden Markov models (HMMs) with Gaussian mixture models (GMMs) state distributions are used for classification. The appended jitter and shimmer features result in an increase in classification accuracy for several illustrative datasets, including the SUSAS dataset for human speaking styles as well as vocalizations labeled by arousal level for African elephant and Rhesus monkey species

    Non-stoichiometry, structure and properties of proton-conducting perovskite oxides

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    We appreciate that EPSRC-EP/P007821/1 and LERG for funding support.The demand for clean and sustainable energy has garnered great interest in new energy materials. Among them, high temperature proton-conducting perovskite oxides are, or can be widely used in clean energy applications (including fuel cells, electrochemical reactors, solid-state separators and supports of catalytic components via various reduction and oxidation reactions) in the intermediate temperature range. The control of defect chemistry is the main strategy to fine tune properties for these applications. This review provides a critical discussion about non-stoichiometry-structure-property relation in terms of structure distortions by intrinsic octahedral titling and extrinsic acceptor doping, chemical stability, hydration behavior, transport properties, and catalytic effects in some typical classes of proton conducting perovskites and perovskite-related derivatives. A good understanding of A-site and B-site non-stoichiometry is also given to allow the perovskite structure with desired properties.PostprintPeer reviewe
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