605 research outputs found

    Elastic Spin Hall effect in Mechanical Graphene

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    We show that spin-orbit interaction and elastic spin-Hall effect can exist in a classical mechanical system consisting of a two-dimensional honeycomb lattice of masses and springs. The band structure shows the presence of splitting at K point induced by the difference of longitudinal and transverse elastic constant, and this splitting can be regarded as an effective Dresselhaus-type spin-orbit coupling. Interestingly, as an initial displacement away from the equilibrium is applied, the time evolution simulation shows that waves of different spin polarization propagates along different directions at the Gamma and K point, which is characteristic of spin-Hall effect. Several cases for spin-Hall effect are also discussed.Comment: 15 pages, 5 figures, and 3395 word

    Finding Related Publications: Extending the Set of Terms Used to Assess Article Similarity.

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    Recommendation of related articles is an important feature of the PubMed. The PubMed Related Citations (PRC) algorithm is the engine that enables this feature, and it leverages information on 22 million citations. We analyzed the performance of the PRC algorithm on 4584 annotated articles from the 2005 Text REtrieval Conference (TREC) Genomics Track data. Our analysis indicated that the PRC highest weighted term was not always consistent with the critical term that was most directly related to the topic of the article. We implemented term expansion and found that it was a promising and easy-to-implement approach to improve the performance of the PRC algorithm for the TREC 2005 Genomics data and for the TREC 2014 Clinical Decision Support Track data. For term expansion, we trained a Skip-gram model using the Word2Vec package. This extended PRC algorithm resulted in higher average precision for a large subset of articles. A combination of both algorithms may lead to improved performance in related article recommendations

    Difference in Thermotolerance Between Green and Red Color Variants of the Japanese Sea Cucumber, Apostichopus japonicus Selenka: Hsp70 and Heat-Hardening Effect

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    We studied thermal tolerance limits, heat-hardening, and Hsp70 to elucidate the difference in thermotolerance between two color variants of the sea Cucumber Apostichopus japonicus. Green and Red variants Occupy different habitats and have different aestivation responses to high temperature in summer. In the absence of heat-hardening the variants showed no difference in the temperature at which 50% of the individuals died: Green 31.49 degrees C; Red, 31.39 degrees C. However. Green specimens acquired higher thermotolerance than Red after a prior Sublethal heat exposure. After 72 h of recovery from a heat-hardening treatment (30 degrees C for 2 h) the survival of Green variants was more than 50% and that of Red wits less than 5% when they were treated at 33 degrees C for 2 h. Levels of mRNA and protein for Hsp70 were significantly higher in Green than Red after the heat shock of 30 degrees C, and the stability of hsp70 mRNA of Green was significantly higher than that of Red. Our findings suggest that within the same species, different variants that have similar thermal limits in the absence of heat-hardening can acquire different thermotolerances after a prior sublethal heat shock. The difference in induced thermotolerance between Green and Red is closely related to the expression pattern of Hsp70, which was partly governed by the stability of hsp70 mRNA

    Image Analysis System of Intelligent Smart Home Based on VR

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    With the increasing aging today, the rich life experience has become a topic that people are urgently concerned about. This research mainly discusses the research and application of VR-based smart home image analysis system. This research combines the intelligent design and implementation of the image analysis system of VR technology. The system uses 2D image processing, segmentation, and recognition to filter out information that is of interest to the image, which is helpful for a reasonable plan for smart homes. During the experiment, a mixed model was used to model the background scene, the background difference method was used to detect the moving target in the image, and then the face detection of the moving target was performed. Through such simple real-time image processing, the necessity of real-time video monitoring is realized. After that, the abnormal image data can be saved to provide effective evidence, and the system will issue a warning after detecting the abnormality, which can effectively monitor specific areas such as home. 110 frames of video clips of people actually walking indoors are used for face detection. Experimentally, the acquisition speed of the VR technology camera is 24 frames per second, and the resolution is 420*250. The research results show that image processing is an indispensable part of the intelligent process of video surveillance. It can also be said that the image processing technology of VR technology is more suitable for the smart and suitable home

    On Properties of Meromorphic Solutions of Certain Difference Painlevé III Equations

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    We mainly study the exponents of convergence of zeros and poles of difference and divided difference of transcendental meromorphic solutions for certain difference Painlevé III equations

    Coriolis force induced topological order for classical mechanical vibrations

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    A two-dimensional mass-spring system with Honeycomb lattice for mimicking phononic quantum Hall effect is proposed. Its band structure shows the existence of Dirac cones and unconventional edge states that is similar to the vibrational modes in graphene. Interestingly, as the system is placed on a constantly rotational coordinate system, the Coriolis force resulted from the non-inertial reference frame provides a possibility to break the time-reversal symmetry. Thus, caused from topologically non-trivial band gaps, phononic edge states are present between bands, which are verified by the calculation of Chern numbers for corresponding bands.Comment: 8 pages, 5 figure

    On The Use Of Nano Fibrillated Kenaf Cellulose Fiber As Reinforcement In Polylactic Acid Biocomposites

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    In this study, nano fibrillated kenaf cellulose (NFKC) derived from kenaf fiber after varying chemico-mechanical treatments were introduced into poly lactic acid (PLA) as reinforcements to improve the mechanical and morphological properties of the biocomposites. The new strategy was aiming to realize the synergistic effects of chemical treatment and mechanical fibrillation process parameters (blending speed and time) for yielding nanofibers and its reinforcement effects on the properties of biocomposites. The yield percentage of the NFKC was determined using centrifugal method and the NFKC fibers with PLA pellet were hot pressed to form NFKC-PLA composites. The distribution and dispersion morphologies of NFKC in NFKC-PLA composites were observed by using optical microscope (OM) and scanning electron microscope (SEM). The reinforcing effect on the mechanical properties of NFKC-PLA composite was investigated by tensile strength test. Average length and diameter of fibrillated fibers were decreased with the concurrent increase of blending speed and time. The maximum increase in tensile strength of 59.32% and elongation of 100% were observed for NFKC-PLA composite with NFKC yielded at a blending speed and time of 15000 rpm and 15 minutes as compared to pure PLA. The tensile properties indicated that the strength and modulus were improved with increased nanofiber contents

    Accelerated Chondrogenic Differentiation of Human Perivascular Stem Cells with NELL-1

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    Osteoarthritis is the leading cause of disability in the US. Consequently, there is a pressing need for restoring the structural and functional properties of diseased articular cartilage. Yet the search for the right combination of proper target cells and growth factors for cartilage regeneration remains challenging. In this study, we first tested the intrinsic chondrogenic differentiation ability of human perivascular stem cells (hPSCs), a novel source of mesenchymal stem cells (MSCs) isolated by fluorescence-activated cell sorting (FACS) from human adipose tissue. A putative prochondrogenic growth factor, NEL-like molecule-1 (NELL-1), was added to the hPSC pellets to upregulate gene expression of chondrogenic markers, including AGGRECAN, COLLAGEN II, and COMP. Furthermore, the addition of NELL-1 to a transforming growth factor beta 3 (TGF-β3) + bone morphogenetic protein-6 (BMP-6) cocktail resulted in the best combinatorial stimulation in accelerating the chondrogenic differentiation of hPSCs, as evidenced by increased gene and protein expression of chondrogenic markers in a shortened induction time without elevating expression of hypertrophic, fibrotic, and osteogenic markers. Mechanistically, this acceleration rendered by NELL-1 may be partially attributed to NELL-1\u27s upregulation of BMP receptors and TGF-β receptor type I in hPSCs for increased responsiveness to BMPs + TGF-βs. In conclusion, lipoaspirate-derived hPSCs present a novel and abundant cell source of MSCs for cartilage regeneration, and the combinatorial application of NELL-1, TGF-β3, and BMP-6 with hPSCs may remarkably enhance and accelerate cartilage repair. © Copyright 2016, Mary Ann Liebert, Inc. 2016

    Inverse Geometry Design of Radiative Enclosures Using Particle Swarm Optimization Algorithms

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    Three different Particle Swarm Optimization (PSO) algorithms—standard PSO, stochastic PSO (SPSO) and differential evolution PSO (DEPSO)—are applied to solve the inverse geometry design problems of radiative enclosures. The design purpose is to satisfy a uniform distribution of radiative heat flux on the designed surface. The design surface is discretized into a series of control points, the PSO algorithms are used to optimize the locations of these points and the Akima cubic interpolation is utilized to approximate the changing boundary shape. The retrieval results show that PSO algorithms can be successfully applied to solve inverse geometry design problems and SPSO achieves the best performance on computational time. The influences of the number of control points and the radiative properties of the media on the retrieval geometry design results are also investigated
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