5,609 research outputs found

    Connected Dominating Set Based Topology Control in Wireless Sensor Networks

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    Wireless Sensor Networks (WSNs) are now widely used for monitoring and controlling of systems where human intervention is not desirable or possible. Connected Dominating Sets (CDSs) based topology control in WSNs is one kind of hierarchical method to ensure sufficient coverage while reducing redundant connections in a relatively crowded network. Moreover, Minimum-sized Connected Dominating Set (MCDS) has become a well-known approach for constructing a Virtual Backbone (VB) to alleviate the broadcasting storm for efficient routing in WSNs extensively. However, no work considers the load-balance factor of CDSsin WSNs. In this dissertation, we first propose a new concept — the Load-Balanced CDS (LBCDS) and a new problem — the Load-Balanced Allocate Dominatee (LBAD) problem. Consequently, we propose a two-phase method to solve LBCDS and LBAD one by one and a one-phase Genetic Algorithm (GA) to solve the problems simultaneously. Secondly, since there is no performance ratio analysis in previously mentioned work, three problems are investigated and analyzed later. To be specific, the MinMax Degree Maximal Independent Set (MDMIS) problem, the Load-Balanced Virtual Backbone (LBVB) problem, and the MinMax Valid-Degree non Backbone node Allocation (MVBA) problem. Approximation algorithms and comprehensive theoretical analysis of the approximation factors are presented in the dissertation. On the other hand, in the current related literature, networks are deterministic where two nodes are assumed either connected or disconnected. In most real applications, however, there are many intermittently connected wireless links called lossy links, which only provide probabilistic connectivity. For WSNs with lossy links, we propose a Stochastic Network Model (SNM). Under this model, we measure the quality of CDSs using CDS reliability. In this dissertation, we construct an MCDS while its reliability is above a preset applicationspecified threshold, called Reliable MCDS (RMCDS). We propose a novel Genetic Algorithm (GA) with immigrant schemes called RMCDS-GA to solve the RMCDS problem. Finally, we apply the constructed LBCDS to a practical application under the realistic SNM model, namely data aggregation. To be specific, a new problem, Load-Balanced Data Aggregation Tree (LBDAT), is introduced finally. Our simulation results show that the proposed algorithms outperform the existing state-of-the-art approaches significantly

    Intestine‐Specific Expression of Human Chimeric Intestinal Alkaline Phosphatase Attenuates Western Diet‐Induced Barrier Dysfunction and Glucose Intolerance

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    Intestinal epithelial cell derived alkaline phosphatase (IAP) dephosphorylates/detoxifies bacterial endotoxin lipopolysaccharide (LPS) in the gut lumen. We have earlier demonstrated that consumption of high‐fat high‐cholesterol containing western type‐diet (WD) significantly reduces IAP activity, increases intestinal permeability leading to increased plasma levels of LPS and glucose intolerance. Furthermore, oral supplementation with curcumin that increased IAP activity improved intestinal barrier function as well as glucose tolerance. To directly test the hypothesis that targeted increase in IAP would protect against WD‐induced metabolic consequences, we developed intestine‐specific IAP transgenic mice where expression of human chimeric IAP is under the control of intestine‐specific villin promoter. This chimeric human IAP contains domains from human IAP and human placental alkaline phosphatase, has a higher turnover number, narrower substrate specificity, and selectivity for bacterial LPS. Chimeric IAP was specifically and uniformly overexpressed in these IAP transgenic (IAPTg) mice along the entire length of the intestine. While IAP activity reduced from proximal P1 segment to distal P9 segment in wild‐type (WT) mice, this activity was maintained in the IAPTg mice. Dietary challenge with WD impaired glucose tolerance in WT mice and this intolerance was attenuated in IAPTg mice. Significant decrease in fecal zonulin, a marker for intestinal barrier dysfunction, in WD fed IAPTg mice and a corresponding decrease in translocation of orally administered nonabsorbable 4 kDa FITC dextran to plasma suggests that IAP overexpression improves intestinal barrier function. Thus, targeted increase in IAP activity represents a novel strategy to improve WD‐induced intestinal barrier dysfunction and glucose intolerance

    Uniform bounds for higher-order semilinear problems in conformal dimension

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    We establish uniform a-priori estimates for solutions of the semilinear Dirichlet problem \begin{equation} \begin{cases} (-\Delta)^m u=h(x,u)\quad&\mbox{in }\Omega,\\ u=\partial_nu=\cdots=\partial_n^{m-1}u=0\quad&\mbox{on }\partial\Omega, \end{cases} \end{equation} where hh is a positive superlinear and subcritical nonlinearity in the sense of the Trudinger-Moser-Adams inequality, either when Ω\Omega is a ball or, provided an energy control on solutions is prescribed, when Ω\Omega is a smooth bounded domain. The analogue problem with Navier boundary conditions is also studied. Finally, as a consequence of our results, existence of a positive solution is shown by degree theory.Comment: Minor correction

    Photometric properties and luminosity function of nearby massive early-type galaxies

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    We perform photometric analyses for a bright early-type galaxy (ETG) sample with 2949 galaxies (Mr<22.5M_{\rm r}<-22.5 mag) in the redshift range of 0.05 to 0.15, drawn from the SDSS DR7 with morphological classification from Galaxy Zoo 1. We measure the Petrosian and isophotal magnitudes, as well as the corresponding half-light radius for each galaxy. We find that for brightest galaxies (Mr<23M_{\rm r}<-23 mag), our Petrosian magnitudes, and isophotal magnitudes to 25 mag/arcsec2{\rm mag/arcsec^2} and 1\% of the sky brightness are on average 0.16 mag, 0.20 mag, and 0.26 mag brighter than the SDSS Petrosian values, respectively. In the first case the underestimations are caused by overestimations in the sky background by the SDSS PHOTO algorithm, while the latter two are also due to deeper photometry. Similarly, the typical half-light radii (r50r_{50}) measured by the SDSS algorithm are smaller than our measurements. As a result, the bright-end of the rr-band luminosity function is found to decline more slowly than previous works. Our measured luminosity densities at the bright end are more than one order of magnitude higher than those of Blanton et al. (2003), and the stellar mass densities at M5×1011MM_{\ast}\sim 5\times10^{11} M_{\odot} and M1012MM_{\ast}\sim 10^{12} M_{\odot} are a few tenths and a factor of few higher than those of Bernardi et al. (2010). These results may significantly alleviate the tension in the assembly of massive galaxies between observations and predictions of the hierarchical structure formation model.Comment: 43 pages, 14 figures, version accepted for publication in the Astrophysical Journa

    Magnetic properties of undoped Cu2O fine powders with magnetic impurities and/or cation vacancies

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    Fine powders of micron- and submicron-sized particles of undoped Cu2O semiconductor, with three different sizes and morphologies have been synthesized by different chemical processes. These samples include nanospheres 200 nm in diameter, octahedra of size 1 micron, and polyhedra of size 800 nm. They exhibit a wide spectrum of magnetic properties. At low temperature, T = 5 K, the octahedron sample is diamagnetic. The nanosphere is paramagnetic. The other two polyhedron samples synthesized in different runs by the same process are found to show different magnetic properties. One of them exhibits weak ferromagnetism with T_C = 455 K and saturation magnetization, M_S = 0.19 emu/g at T = 5 K, while the other is paramagnetic. The total magnetic moment estimated from the detected impurity concentration of Fe, Co, and Ni, is too small to account for the observed magnetism by one to two orders of magnitude. Calculations by the density functional theory (DFT) reveal that cation vacancies in the Cu2O lattice are one of the possible causes of induced magnetic moments. The results further predict that the defect-induced magnetic moments favour a ferromagnetically coupled ground state if the local concentration of cation vacancies, n_C, exceeds 12.5%. This offers a possible scenario to explain the observed magnetic properties. The limitations of the investigations in the present work, in particular in the theoretical calculations, are discussed and possible areas for further study are suggested.Comment: 20 pages, 5 figures 2 tables, submitted to J Phys Condense Matte

    Ginsenosides are novel naturally-occurring aryl hydrocarbon receptor ligands.

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    The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor that mediates many of the biological and toxicological actions of structurally diverse chemicals. In this study, we examined the ability of a series of ginsenosides extracted from ginseng, a traditional Chinese medicine, to bind to and activate/inhibit the AHR and AHR signal transduction. Utilizing a combination of ligand and DNA binding assays, molecular docking and reporter gene analysis, we demonstrated the ability of selected ginsenosides to directly bind to and activate the guinea pig cytosolic AHR, and to stimulate/inhibit AHR-dependent luciferase gene expression in a recombinant guinea pig cell line. Comparative studies revealed significant species differences in the ability of ginsenosides to stimulate AHR-dependent gene expression in guinea pig, rat, mouse and human cell lines. Not only did selected ginsenosides preferentially activate the AHR from one species and not others, mouse cell line was also significantly less responsive to these chemicals than rat and guinea pig cell lines, but the endogenous gene CYP1A1 could still be inducted in mouse cell line. Overall, the ability of these compounds to stimulate AHR signal transduction demonstrated that these ginsenosides are a new class of naturally occurring AHR agonists

    BSML: A Binding Schema Markup Language for Data Interchange in Problem Solving Environments (PSEs)

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    We describe a binding schema markup language (BSML) for describing data interchange between scientific codes. Such a facility is an important constituent of scientific problem solving environments (PSEs). BSML is designed to integrate with a PSE or application composition system that views model specification and execution as a problem of managing semistructured data. The data interchange problem is addressed by three techniques for processing semistructured data: validation, binding, and conversion. We present BSML and describe its application to a PSE for wireless communications system design

    An association study between polymorphism of alcohol dehydrogenase (ADH1B), aldehyde dehydrogenase (ALDH2), cytochrome (CYP4502E1), Catechol-OMethyltransferase (COMT) and 5-hydroxytryptamine transporter (5-HTT)...

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    Full Title: An association study between polymorphism of alcohol dehydrogenase (ADH1B), aldehyde dehydrogenase (ALDH2), cytochrome (CYP4502E1), Catechol-OMethyltransferase (COMT) and 5-hydroxytryptamine transporter (5-HTT) genes in Yunnan Han population with alcohol dependenceAbstact: Alcohol dependence (AD) is a complex disease resulting from the inheritance of several susceptible genes and multiple environmental determinants. The aim of this study was to identify the genetic risk factors which include alcohol metabolizing genes and neurotransmitter related genes for alcoholism in Yunnan Han population. Eight allelic variants of five genes were genotyped from 332 Yunnan Han individuals (including 118 alcohol-dependent patients (DSM-IV criteria) and 214 controls) using PCRRFLP method. Those polymorphic sites included alcohol dehydrogenase (ADH1B), aldehyde dehydrogenase (ALDH2), cytochrome P-4502E1 (CYP2E1) PstI, Catechol-O-Methyltransferase (COMT) rs2075507 (5’region), rs737865 (intron1), rs4680 (Val158Met), rs165599 (3’region) and serotonin transporter (5-HTTLPR). Both genotype and allele frequencies of ALDH2 and CYP4502E1 as well as the allele frequency of ADH1B gene differed significantly between AD group and control group. The proportion of ALDH2 *1/*2 genotype and *2 allele was significantly smaller in patients than that in controls (X2 = 6.554, p = 0.038; X2 = 4.906, p = 0.027), while the proportion of c2 allele of CYP4502E1 was significantly higher (X2 = 4.410, p = 0.036). Compared with the controls, the frequencies of the 5-HTTLPR L/L genotype and COMT rs737865 C/C genotype were significantly lower in AD group. Twelve COMT haplotypes (rs2075507, rs737865, rs4680 and rs165599) defined as H1 to H12 were obtained in this major minority population. The prevalence of the haplotype H1 ‘‘A-C-A-A’’ was significantly greater in alcoholics than the prevalence in their respective control group. There were no significant differences in the genotype frequencies of the COMT rs2075507, rs4680 and rs165599 polymorphisms between alcoholics and controls. COMT rs2075507 and rs737865 polymorphisms were in complete linkage disequilibrium in Han population of Yunnan Province. This study indicates that polymorphisms of ADH1B, ALDH2, CYP4502E1, COMT and 5-HTT were significantly associated with AD in Han majority. The ADH1B *2, ALDH2 *2 alleles, 5-HTTLPR L/L genotype and C/C genotype of the COMT rs737865 polymorphism had an important role in reducing the risk of AD while the c2 allele of CYP4502E1 increased the risk of AD. Therefore, the A-C-A-A haplotype may be a dangerous factor leading to AD.Key words: Yunnan Han population, polymorphism, alcohol dependence, genetic risk factor
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