12,864 research outputs found

    From Filter Paper to Functional Actuator by Poly(ionic liquid)-Modified Graphene Oxide

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    A commercially available membrane filter paper composed of mixed cellulose esters bearing typically an interconnected pore structure was transformed into a stimuli-responsive bilayer actuator by depositing a thin film of poly(ionic liquid)-modified graphene oxide sheets (GO-PIL) onto the filter paper. In acetone vapor, the as-synthesized bilayer actuator bent readily into multiple loops at a fast speed with the GO-PIL top film inwards. Upon pulling back into air the actuator recovered their original shape. The asymmetric swelling of the top GO-PIL film and the bottom porous filter paper towards organic vapor offers a favorably synergetic function to drive the actuation. The PIL polymer chains in the hybrid film were proven crucial to enhance the adhesion strength between the GO sheets and the adjacent filter paper to avoid interfacial delamination and thus improve force transfer. The overall construction allows a prolonged lifetime of the bilayer actuator under constant operation, especially when compared to that of the GO/filter paper bilayer actuator without PIL.Comment: 23 pages, 7 figure

    Higher bottom and bottom-strange mesons

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    Motivated by the recent observation of the orbital excitation B(5970)B(5970) by CDF collaboration, we have performed a systematical study of the mass spectrum and strong decay patterns of the higher BB and BsB_s mesons. Hopefully the present investigation may provide valuable clues to further experimental exploration of these intriguing excited heavy mesons.Comment: 13 pages, 11 figures, 10 tables. More discussions and references added. Accepted by Phys. Rev.

    Effects of Neuropeptide y on Stem Cells and Their Potential Applications in Disease Therapy

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    Neuropeptide Y (NPY), a 36-amino acid peptide, is widely distributed in the central and peripheral nervous systems and other peripheral tissues. It takes part in regulating various biological processes including food intake, circadian rhythm, energy metabolism, and neuroendocrine secretion. Increasing evidence indicates that NPY exerts multiple regulatory effects on stem cells. As a kind of primitive and undifferentiated cells, stem cells have the therapeutic potential to replace damaged cells, secret paracrine molecules, promote angiogenesis, and modulate immunity. Stem cell-based therapy has been demonstrated effective and considered as one of the most promising treatments for specific diseases. However, several limitations still hamper its application, such as poor survival and low differentiation and integration rates of transplanted stem cells. The regulatory effects of NPY on stem cell survival, proliferation, and differentiation may be helpful to overcome these limitations and facilitate the application of stem cell-based therapy. In this review, we summarized the regulatory effects of NPY on stem cells and discussed their potential applications in disease therapy

    Depositional evolution and models for a deep-lacustrine gravity flow system in a half-graben rifted sag, Beibuwan Basin, South China Sea

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    The Paleogene Liushagang Formation is part of the Fushan Sag, a continental lacustrine basin located at theSoutheastern margin of the Beibuwan Basin, South China Sea. Further understanding of the deep-water gravityflow deposits in this formation will be conducive to lithologic reservoir exploration in the sag. In this study,three members of the Liushagang Formation, SQEls3 SQEls2 and SQEls1, from old to young, are used withcore observation, well log data, and three-dimensional seismic data to identify four deep-lacustrine gravity flowlithofacies including their vertical and lateral relationships within the depositional system. The results are thenused to establish a deep-water gravity flow depositional model. Four types of gravity flow lithofacies developed inthe sag: sandy debrite, turbidite, sandy slump, and bottom-current deposits. Sand-rich sub-lacustrine fan depositswith typical turbidite channels were developed mainly in the western depression, whereas distal isolated lobesformed by sandy debrite flow deposits occurred mainly in the eastern depression. The results obtained in this studywill be helpful in the research of gravity flows in similar continental lacustrine environments

    Selection of Latent Variables for Multiple Mixed-Outcome Models

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    Latent variable models have been widely used for modeling the dependence structure of multiple outcomes data. As the formulation of a latent variable model is often unknown a priori, misspecification could distort the dependence structure and lead to unreliable model inference. More- over, the multiple outcomes are often of varying types (e.g., continuous and ordinal), which presents analytical challenges. In this article, we present a class of general latent variable models that can accommodate mixed types of outcomes, and further propose a novel selection approach that simultaneously selects latent variables and estimates model parameters. We show that the proposed estimators are consistent, asymptotically normal, and have the Oracle property. The practical utility of the methods is confirmed via simulations as well as an application to the analysis of a dataset collected in the World Values Survey (WVS), a global research project that explores peoples\u27 values and beliefs and what social and personal characteristics might influence them

    Synergistic Effects between Phosphorylation of Phospholamban and Troponin I Promote Relaxation at Higher Heart Rate

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    We hypothesized that the extent of frequency-dependent acceleration of relaxation (FDAR) would be less than that of isoproterenol-(ISO-)dependent acceleration of relaxation (IDAR) at the same increment of heart rates, and ISO may improve FDAR. Cardiac function and phosphorylation of PLB and cTnI were compared in pacing, ISO treatment, and combined pacing and ISO treatment in isolated working heart. The increase in cardiac output and the degree of relaxation was less in pacing than in ISO treatment at the same increment of heart rates. The increasing stimulation frequency induced more significant relaxant effect in ISO perfusion than that in physiological salt perfusion. The pacing only phosphorylated PLB at Thr17, but ISO induced phosphorylation of cTnI and PLB at Ser16 and Thr17. Those results suggest that the synergistic effects of PLB and cTnI induce higher degree of relaxation which makes a sufficient diastolic filling of the ventricle at higher heart rate
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