1,542 research outputs found

    Excitation of Radiative Polaritons by Polarized Broadband Infrared Radiation in Thin Oxide Films Deposited by Atomic Layer Deposition

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    This work contributes to the understanding of infrared radiation interaction with matter and its absorption for energy harvesting purposes. By exciting radiative polaritons in thin oxide filmswith polarized infrared radiation, a further evidence is collected that a link exists between radiative polaritons and the heat recovery mechanism hypothesized in previous research. In the voltage transient occurring when the infrared radiation is turned on, the observed time necessary to reach the maximum voltage and the voltage intensity versus angle of incidence exhibit a mismatch when generated by polarized and nonpolarized infrared radiation. The existence of collective charge oscillation modes in the semiconductor-based elements of the thermoelectric power generators supporting the heat recovery mechanism is suggested as the main source of the discrepancy

    Heat recovery mechanism in the excitation of radiative polaritons by broadband infrared radiation in thin oxide films

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    This work probes radiative polaritons in thin oxide layers as a mean to capture and absorb broadband infrared radiation and transform it into heat. A heat recovery mechanism, based on the Seebeck effect, is used as the tool of the investigation. Heat production challenges the current understanding which views the excitation of radiative polaritons as only accompanied by the emission of electromagnetic radiation. The heat recovery mechanism presented here can inspire the design of infrared energy harvesting devices, similar to photovoltaic cells, and other devices to convert energy from a wide range of the electromagnetic radiation spectrum using thermoelectric power generators

    Graphene inclusion controlling conductivity and gas sorption of metal-organic framework

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    A general approach to prepare composite films of metal–organic frameworks and graphene has been developed. Films of copper(ii)-based HKUST-1 and HKUST-1/graphene composites were grown solvothermally on glassy carbon electrodes. The films were chemically tethered to the substrate by diazonium electrografting resulting in a large electrode coverage and good stability in solution for electrochemical studies. HKUST-1 has poor electrical conductivity, but we demonstrate that the addition of graphene to HKUST-1 partially restores the electrochemical activity of the electrodes. The enhanced activity, however, does not result in copper(ii) to copper(i) reduction in HKUST-1 at negative potentials. The materials were characterised in-depth: microscopy and grazing incidence X-ray diffraction demonstrate uniform films of crystalline HKUST-1, and Raman spectroscopy reveals that graphene is homogeneously distributed in the films. Gas sorption studies show that both HKUST-1 and HKUST-1/graphene have a large CO(2)/N(2) selectivity, but the composite has a lower surface area and CO(2) adsorption capacity in comparison with HKUST-1, while CO(2) binds stronger to the composite at low pressures. Electron paramagnetic resonance spectroscopy reveals that both monomeric and dimeric copper units are present in the materials, and that the two materials behave differently upon hydration, i.e. HKUST-1/graphene reacts slower by interaction with water. The changed gas/vapour sorption properties and the improved electrochemical activity are two independent consequences of combining graphene with HKUST-1

    Physical Activity, Obesity, Nutritional Health and Quality of Life in Low-Income Hispanic Adults With Diabetes

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    The study examined relationships among age, body mass index (BMI), physical activity, nutritional health, quality of life, and health-related quality of life in Hispanic adults with diabetes (N = 59) using the PRECEDE-PROCEED planning model as a framework. Data were collected through face-to-face interviews at clinics and communities. A regression model with predisposing factors (age, BMI), and behavior (nutritional health and physical activity) significantly predicted quality of life (R2 = 0.21, F = 3.63, p < .05) explaining 21% of variance. Physical activity and nutrition were the strongest predictors. Culturally competent intervention strategies must include factors that improve and enhance quality of life

    Towards a Learner-Centered Explainable AI: Lessons from the learning sciences

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    In this short paper, we argue for a refocusing of XAI around human learning goals. Drawing upon approaches and theories from the learning sciences, we propose a framework for the learner-centered design and evaluation of XAI systems. We illustrate our framework through an ongoing case study in the context of AI-augmented social work.Comment: 7 pages, 2 figure

    Synthesis and characterization of hybrid organic-inorganic materials based on sulphonated polyamideimide and silica

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    The preparation of hybrid organic–inorganic membrane materials based on a sulphonated polyamideimide resin and silica filler has been studied. The method allows the sol–gel process to proceed in the presence of a high molecular weight polyamideimide, resulting in well dispersed silica nanoparticles (<50 nm) within the polymer matrix with chemical bonding between the organic and inorganic phases. Tetraethoxysilane (TEOS) was used as the silica precursor and the organosilicate networks were bonded to the polymer matrix via a coupling agent aminopropyltriethoxysilane (APTrEOS). The structure and properties of these hybrid materials were characterized via a range of techniques including FTIR, TGA, DSC, SEM and contact angle analysis. It was found that the compatibility between organic and inorganic phases has been greatly enhanced by the incorporation of APTrEOS. The thermal stability and hydrophilic properties of hybrid materials have also been significantly improved

    What are the current and projected future cost and health-related quality of life implications of scaling up cognitive stimulation therapy?

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    Objectives: Cognitive stimulation therapy (CST) is one of the few non-pharmacological interventions for people living with dementia shown to be effective and cost-effective. What are the current and future cost and health-related quality of life implications of scaling-up CST to eligible new cases of dementia in England? Methods/design: Data from trials were combined with microsimulation and macrosimulation modelling to project future prevalence, needs and costs. Health and social costs, unpaid care costs and quality-adjusted life years (QALYs) were compared with and without scaling-up of CST and follow-on maintenance CST (MCST). Results: Scaling-up group CST requires year-on-year increases in expenditure (mainly on staff), but these would be partially offset by reductions in health and care costs. Unpaid care costs would increase. Scaling-up MCST would also require additional expenditure, but without generating savings elsewhere. There would be improvements in general cognitive functioning and health-related quality of life, summarised in terms of QALY gains. Cost per QALY for CST alone would increase from £12,596 in 2015 to £19,573 by 2040, which is below the threshold for cost-effectiveness used by the National Institute for Health and Care Excellence (NICE). Cost per QALY for CST and MCST combined would grow from £19,883 in 2015 to £30,906 by 2040, making it less likely to be recommended by NICE on cost-effectiveness grounds. Conclusions: Scaling-up CST England for people with incident dementia can improve lives in an affordable, cost-effective manner. Adding MCST also improves health-related quality of life, but the economic evidence is less compelling

    Yeast pex1 cells contain peroxisomal ghosts that import matrix proteins upon reintroduction of Pex1

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    Pex1 and Pex6 are two AAA-ATPases that play a crucial role in peroxisome biogenesis. We have characterized the ultrastructure of the Saccharomyces cerevisiae peroxisome-deficient mutants pex1 and pex6 by various high-resolution electron microscopy techniques. We observed that the cells contained peroxisomal membrane remnants, which in ultrathin cross sections generally appeared as double membrane rings. Electron tomography revealed that these structures consisted of one continuous membrane, representing an empty, flattened vesicle, which folds into a cup shape. Immunocytochemistry revealed that these structures lack peroxisomal matrix proteins but are the sole sites of the major peroxisomal membrane proteins Pex2, Pex10, Pex11, Pex13, and Pex14. Upon reintroduction of Pex1 in Pex1-deficient cells, these peroxisomal membrane remnants (ghosts) rapidly incorporated peroxisomal matrix proteins and developed into peroxisomes. Our data support earlier views that Pex1 and Pex6 play a role in peroxisomal matrix protein import

    Identification of a novel loss-of-function calcium channel gene mutation in short QT syndrome (SQTS6)

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    Aims Short QT syndrome (SQTS) is a genetically determined ion-channel disorder, which may cause malignant tachyarrhythmias and sudden cardiac death. Thus far, mutations in five different genes encoding potassium and calcium channel subunits have been reported. We present, for the first time, a novel loss-of-function mutation coding for an L-type calcium channel subunit. Methods and results The electrocardiogram of the affected member of a single family revealed a QT interval of 317 ms (QTc 329 ms) with tall, narrow, and symmetrical T-waves. Invasive electrophysiological testing showed short ventricular refractory periods and increased vulnerability to induce ventricular fibrillation. DNA screening of the patient identified no mutation in previously known SQTS genes; however, a new variant at a heterozygous state was identified in the CACNA2D1 gene (nucleotide c.2264G > C; amino acid p.Ser755Thr), coding for the Cavα2δ-1 subunit of the L-type calcium channel. The pathogenic role of the p.Ser755Thr variant of the CACNA2D1 gene was analysed by using co-expression of the two other L-type calcium channel subunits, Cav1.2α1 and Cavβ2b, in HEK-293 cells. Barium currents (IBa) were recorded in these cells under voltage-clamp conditions using the whole-cell configuration. Co-expression of the p.Ser755Thr Cavα2δ-1 subunit strongly reduced the IBa by more than 70% when compared with the co-expression of the wild-type (WT) variant. Protein expression of the three subunits was verified by performing western blots of total lysates and cell membrane fractions of HEK-293 cells. The p.Ser755Thr variant of the Cavα2δ-1 subunit was expressed at a similar level compared with the WT subunit in both fractions. Since the mutant Cavα2δ-1 subunit did not modify the expression of the pore-forming subunit of the L-type calcium channel, Cav1.2α1, it suggests that single channel biophysical properties of the L-type channel are altered by this variant. Conclusion In the present study, we report the first pathogenic mutation in the CACNA2D1 gene in humans, which causes a new variant of SQTS. It remains to be determined whether mutations in this gene lead to other manifestations of the J-wave syndrom
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