94 research outputs found

    Multiband slot antennas for metal back cover mobile handsets

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    New multiband integrated slot antennas for mobile handsets are presented for GSM, DCS, PCS and WCDMA, GPS and WIFI 2.4 GHz. Prototypes, both simulated and measured, are realised in the metal back cover away from the hand. Perturbations due to tissue proximity are simulated using a CTIA compliant hand phantom

    Multi-Agent Reinforcement Learning Guided by Signal Temporal Logic Specifications

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    Reward design is a key component of deep reinforcement learning, yet some tasks and designer's objectives may be unnatural to define as a scalar cost function. Among the various techniques, formal methods integrated with DRL have garnered considerable attention due to their expressiveness and flexibility to define the reward and requirements for different states and actions of the agent. However, how to leverage Signal Temporal Logic (STL) to guide multi-agent reinforcement learning reward design remains unexplored. Complex interactions, heterogeneous goals and critical safety requirements in multi-agent systems make this problem even more challenging. In this paper, we propose a novel STL-guided multi-agent reinforcement learning framework. The STL requirements are designed to include both task specifications according to the objective of each agent and safety specifications, and the robustness values of the STL specifications are leveraged to generate rewards. We validate the advantages of our method through empirical studies. The experimental results demonstrate significant reward performance improvements compared to MARL without STL guidance, along with a remarkable increase in the overall safety rate of the multi-agent systems

    Lack of association between polymorphisms of MASP2 and susceptibility to SARS coronavirus infection

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    <p>Abstract</p> <p>Background</p> <p>The pathogenesis of severe acute respiratory disease syndrome (SARS) is not fully understood. One case-control study has reported an association between susceptibility to SARS and <it>mannan-binding lectin </it>(<it>MBL</it>) in China. As the downstream protein of <it>MBL</it>, variants of the <it>MBL</it>-associated serine protease-2 (<it>MASP2</it>) gene may be associated with SARS coronavirus (SARS-CoV) infection in the same population.</p> <p>Methods</p> <p>Thirty individuals with SARS were chosen for analysis of <it>MASP2 </it>polymorphisms by means of PCR direct sequencing. Tag single nucleotide polymorphisms (tagSNPs) were chosen using pairwise tagging algorithms. The frequencies of four tag SNPs (rs12711521, rs2261695, rs2273346 and rs7548659) were ascertained in 376 SARS patients and 523 control subjects, using the Beckman SNPstream Ultra High Throughput genotyping platform.</p> <p>Results</p> <p>There is no significant association between alleles or genotypes of the <it>MASP2 </it>tagSNP and susceptibility to SARS-CoV in both Beijing and Guangzhou populations. Diplotype (rs2273346 and rs12711521)were analyzed for association with susceptibility to SARS, no statistically significant evidence of association was observed. The Beijing and Guangzhou sample groups were homogeneous regarding demographic and genetic parameters, a joined analysis also showed no statistically significant evidence of association.</p> <p>Conclusion</p> <p>Our data do not suggest a role for <it>MASP2 </it>polymorphisms in SARS susceptibility in northern and southern China.</p

    SIRT1 Activation by Resveratrol Alleviates Cardiac Dysfunction via Mitochondrial Regulation in Diabetic Cardiomyopathy Mice

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    Background. Diabetic cardiomyopathy (DCM) is a major threat for diabetic patients. Silent information regulator 1 (SIRT1) has a regulatory effect on mitochondrial dynamics, which is associated with DCM pathological changes. Our study aims to investigate whether resveratrol, a SRIT1 activator, could exert a protective effect against DCM. Methods and Results. Cardiac-specific SIRT1 knockout (SIRT1KO) mice were generated using Cre-loxP system. SIRT1KO mice displayed symptoms of DCM, including cardiac hypertrophy and dysfunction, insulin resistance, and abnormal glucose metabolism. DCM and SIRT1KO hearts showed impaired mitochondrial biogenesis and function, while SIRT1 activation by resveratrol reversed this in DCM mice. High glucose caused increased apoptosis, impaired mitochondrial biogenesis, and function in cardiomyocytes, which was alleviated by resveratrol. SIRT1 deletion by both SIRT1KO and shRNA abolished the beneficial effects of resveratrol. Furthermore, the function of SIRT1 is mediated via the deacetylation effect on peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), thus inducing increased expression of nuclear respiratory factor 1 (NRF-1), NRF-2, estrogen-related receptor-α (ERR-α), and mitochondrial transcription factor A (TFAM). Conclusions. Cardiac deletion of SIRT1 caused phenotypes resembling DCM. Activation of SIRT1 by resveratrol ameliorated cardiac injuries in DCM through PGC-1α-mediated mitochondrial regulation. Collectively, SIRT1 may serve as a potential therapeutic target for DCM

    A novel Fas ligand plays an important role in cell apoptosis of Crassostrea hongkongensis: molecular cloning, expression profiles and functional identification of ChFasL

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    BackgroundApoptosis regulates normal development, homeostasis, immune tolerance and response to environmental stress by eliminating unwanted or diseased cells, and plays a key role in non-specific immunity of invertebrates. The exogenous pathway mediated by death receptors and death ligands is a very important pathway for cell apoptosis. Death ligands are mainly members of the tumour necrosis factor (TNF) family, of which FasL is an important member. The deep involvement of FasL in vertebrates cell apoptosis and immunity has been reported many times, but there is limited research on the FasL gene in shellfish, and its functional importance in oyster cell apoptosis and immunity remains unclear.MethodsThe full length of ChFasL was identified and cloned based on the genome of Crassostrea hongkongensis. Quantitative PCR was used to detect the relative expression of ChFasL in different developmental stages and tissues, as well as the changes of relative expression in hemocytes after bacterial infection. The expression position of ChFasL in HEK293T cells was also located by subcellular localization, and the effect of increased recombinant protein content on the activity of reporter genes p53 and p21 was studied by dual-fluorescence reporter gene. Finally, the changes of apoptosis rate in hemocytes after ChFasL silencing was identified by RNA interference technology.ResultsWe identified a novel FasL gene from C. hongkongensis and named it ChFasL. We found that ChFasL has potential N-linked glycosylation site, a transmembrane domain and a TNF region, which was a typical characteristics of TNF family. ChFasL was expressed in all developmental stages of larvae and in all tissues of oysters. After stimulation by V. alginolyticus or S. haemolyticus, its relative expression in hemocytes increased significantly, suggesting that ChFasL was deeply engaged in the immune response process of C. hongkongensis to external microbial stimulation. The results of subcellular localization showed that ChFasL was mainly distributed in the cytoplasm of HEK293T cells. With the overexpression of the recombinant protein pcDNA3 1- ChFasL, the activity of p53 and p21 significantly increased, showing a positive regulatory effect. Moreover, after dsRNA successfully reduced the relative expression of ChFasL, the apoptosis rate of hemocytes was significantly lower than that the dsGFP group.ConclusionThese results comprehensively confirmed the important role of ChFasL in the apoptosis process of C. hongkongensis, which provided the basis and premise for the in-depth understanding of the immune function of apoptosis in molluscs, and also contributed to the research on the pathogenic death mechanism and disease resistance breeding of marine bivalves

    Surface chromium on Terracotta Army bronze weapons is neither an ancient anti-rust treatment nor the reason for their good preservation.

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    For forty years, there has been a widely held belief that over 2,000 years ago the Chinese Qin developed an advanced chromate conversion coating technology (CCC) to prevent metal corrosion. This belief was based on the detection of chromium traces on the surface of bronze weapons buried with the Chinese Terracotta Army, and the same weapons' very good preservation. We analysed weapons, lacquer and soils from the site, and conducted experimental replications of CCC and accelerated ageing. Our results show that surface chromium presence is correlated with artefact typology and uncorrelated with bronze preservation. Furthermore we show that the lacquer used to cover warriors and certain parts of weapons is rich in chromium, and we demonstrate that chromium on the metals is contamination from nearby lacquer after burial. The chromium anti-rust treatment theory should therefore be abandoned. The good metal preservation probably results from the moderately alkaline pH and very small particle size of the burial soil, in addition to bronze composition

    Effect of Ligusticum wallichii Aqueous Extract on Oxidative Injury and Immunity Activity in Myocardial Ischemic Reperfusion Rats

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    We investigated the efficacy of Ligusticum wallichi aqueous extract (LWE) for myocardial protection against ischemia-reperfusion injury. Rats were fed for five weeks with either a control diet (sham and ischemia reperfusion (IR) model control groups) or a diet mixed with 0.2%, 0.4% or 0.6% Ligusticum wallichi extract. At the end of the five week period, hearts were excised and subjected to global ischemia for 30 min followed by reperfusion for 2 h. The hearts were compared for indices of oxidative stress and immunity activities. Administration of Ligusticum wallichi extract significantly decreased serum TNF-α, IL-6, IL-8, NO, MIP-1α, CRP and myocardium MDA levels, and serum CK, LDH and AST activities, and increased myocardium Na+-K+-ATPase, Ca2+-Mg2+-ATPase, NOS, SOD, CAT, GSH-Px and TAOC activities. The results indicate that Ligusticum wallichii extract treatment can enhance myocardial antioxidant status and improve the immunity profile in ischemic-reperfusion rats

    On the Origin of Tibetans and Their Genetic Basis in Adapting High-Altitude Environments

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    Since their arrival in the Tibetan Plateau during the Neolithic Age, Tibetans have been well-adapted to extreme environmental conditions and possess genetic variation that reflect their living environment and migratory history. To investigate the origin of Tibetans and the genetic basis of adaptation in a rigorous environment, we genotyped 30 Tibetan individuals with more than one million SNP markers. Our findings suggested that Tibetans, together with the Yi people, were descendants of Tibeto-Burmans who diverged from ancient settlers of East Asia. The valleys of the Hengduan Mountain range may be a major migration route. We also identified a set of positively-selected genes that belong to functional classes of the embryonic, female gonad, and blood vessel developments, as well as response to hypoxia. Most of these genes were highly correlated with population-specific and beneficial phenotypes, such as high infant survival rate and the absence of chronic mountain sickness

    Evaluation of the Antioxidant Potential of Salvia miltiorrhiza Ethanol Extract in a Rat Model of Ischemia-Reperfusion Injury

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    The present study was undertaken to evaluate the protection potential of ethanol extract of Salvia miltiorrhiza (SMEE) against oxidative injury in the ischemia-reperfusion (I/R) model of rats in vivo. Rats were divided into six groups of 10 rats each. Group I/R model and sham were fed with a standard rat chow, groups SMEE I and SMEE II were fed with a standard rat chow and 400 or 800 mg/kg b.w. ethanol extract for 12 days before the beginning of I/R studies. Positive control group was fed with a standard rat chow and salvianolic acid B (55 mg/kg b.w.) or tanshinone II-A (55 mg/kg b.w.) for 12 days before the beginning of I/R studies. To produce I/R, the left anterior descending artery (LAD) was occluded in anesthetized rats for 15 min, followed by 120 min reperfusion. Infarct sizes were found significantly decreased in SMEE-treated and positive control groups compared to I/R model group. Serum AST, LDH and CK-MB activities were significantly reduced and myocardium Na+-K+ ATPase, Ca2+-Mg2+ ATPase activities and antioxidant enzyme activities (SOD, CAT, GSH-Px) were markedly increased in SMEE-treated and salvianolic acid B or tanshinone II-A positive control groups compared to the I/R model group. Pretreatment of S. miltiorrhiza ethanol extract and salvianolic acid B or tanshinone II-A dose-dependently reduced significantly myocardium MDA level, ROS and NOS activities and enhanced myocardium GSH level in I/R rats compared to I/R rats model. In conclusion, we clearly demonstrated that S. miltiorrhiza ethanol extract pretreatment can decrease oxidative injury in rats subjected to myocardial I/R
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