8,482 research outputs found

    Modification of serum adiponectin and CINC-1 levels by intermittent hypoxia and/or hyperlipidemia in vivo

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    published_or_final_versionThe 15th Medical Research Conference, Department of Medicine, The University of Hong Kong, Hong Kong, 16 January 2010. In Hong Kong Medical Journal, 2010, v. 16, suppl. 1, p. 22, abstract no. 2

    Cellular mechanisms involved in intermittent hypoxia-induced heart damage in rat

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    Poster PresentationBACKGROUND: Obstructive sleep apnoea (OSA), characterised by intermittent hypoxia (IH) during sleep, is increasingly recognised as an independent risk factor of cardiovascular diseases (CVD). OSA has been reported to be associated with changes in the levels of circulating oxidative stress and inflammatory markers as well as dyslipidemia, supporting their mediating roles in cardiovascular pathogenesis. This study aimed to investigate the ...published_or_final_versionThe 17th Medical Research Conference, Department of Medicine, The University of Hong Kong, Hong Kong, 14 January 2012. In Hong Kong Medical Journal, 2012, v. 18 n. 1, suppl. 1, p. 23, abstract no. 2

    Large Extra Dimension effects through Light-by-Light Scattering at the CERN LHC

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    Observing light-by-light scattering at the Large Hadron Collider (LHC) has received quite some attention and it is believed to be a clean and sensitive channel to possible new physics. In this paper, we study the diphoton production at the LHC via the process pppγγppγγp\rm pp\rightarrow p\gamma\gamma p\rightarrow p\gamma\gamma p through graviton exchange in the Large Extra Dimension (LED) model. Typically, when we do the background analysis, we also study the Double Pomeron Exchange (DPE) of γγ\gamma\gamma production. We compare its production in the quark-quark collision mode to the gluon-gluon collision mode and find that contributions from the gluon-gluon collision mode are comparable to the quark-quark one. Our result shows, for extra dimension δ=4\delta=4, with an integrated luminosity L=200fb1\rm {\cal L} = 200 fb^{-1} at the 14 TeV LHC, that diphoton production through graviton exchange can probe the LED effects up to the scale MS=5.06(4.51,5.11)TeV\rm M_S=5.06 (4.51, 5.11) TeV for the forward detector acceptance ξ1(ξ2,ξ3)\xi_1 (\xi_2, \xi_3), respectively, where 0.0015<ξ1<0.50.0015<\xi_1<0.5, 0.1<ξ2<0.50.1<\xi_2<0.5 and 0.0015<ξ3<0.150.0015<\xi_3<0.15.Comment: 25 pages. 7 figs. Change some grammatical error

    Role of heme oxygenase-1 in intermittent hypoxia-induced inflammation and oxidative stress in eAhy 926 endothelial cell line

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    published_or_final_versionThe 16th Medical Research Conference (MRC), Department of Medicine, The University of Hong Kong, Hong Kong, China, 22 January 2011. In Hong Kong Medical Journal, 2011, v. 17 n. 1, suppl. 1, p. 29, abstract no. 4

    Performance of Monolayer Graphene Nanomechanical Resonators with Electrical Readout

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    The enormous stiffness and low density of graphene make it an ideal material for nanoelectromechanical (NEMS) applications. We demonstrate fabrication and electrical readout of monolayer graphene resonators, and test their response to changes in mass and temperature. The devices show resonances in the MHz range. The strong dependence of the resonant frequency on applied gate voltage can be fit to a membrane model, which yields the mass density and built-in strain. Upon removal and addition of mass, we observe changes in both the density and the strain, indicating that adsorbates impart tension to the graphene. Upon cooling, the frequency increases; the shift rate can be used to measure the unusual negative thermal expansion coefficient of graphene. The quality factor increases with decreasing temperature, reaching ~10,000 at 5 K. By establishing many of the basic attributes of monolayer graphene resonators, these studies lay the groundwork for applications, including high-sensitivity mass detectors

    Band-gap expansion in the surface-localized electronic structure of MoS2(0002)

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    The electronic band structure of MoS2 single crystals has been investigated using angle-resolved photoelectron spectroscopy and first-principles calculations. The orbital symmetry and k dispersion of these electronic states responsible for the direct and the indirect electronic band gaps have been unambiguously determined. By experimentally probing an increase of the electronic band gap, we conclude that a MoS2 (0002) surface localized state exists just below the valence band maximum at the Gamma point. This electronic state originates from the sulfur planes within the topmost layer. Our comprehensive study addresses the surface electronic structure of MoS2 and the role of van der Waals interlayer interactions.open112625Nsciescopu

    N-player quantum games in an EPR setting

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    The NN-player quantum game is analyzed in the context of an Einstein-Podolsky-Rosen (EPR) experiment. In this setting, a player's strategies are not unitary transformations as in alternate quantum game-theoretic frameworks, but a classical choice between two directions along which spin or polarization measurements are made. The players' strategies thus remain identical to their strategies in the mixed-strategy version of the classical game. In the EPR setting the quantum game reduces itself to the corresponding classical game when the shared quantum state reaches zero entanglement. We find the relations for the probability distribution for NN-qubit GHZ and W-type states, subject to general measurement directions, from which the expressions for the mixed Nash equilibrium and the payoffs are determined. Players' payoffs are then defined with linear functions so that common two-player games can be easily extended to the NN-player case and permit analytic expressions for the Nash equilibrium. As a specific example, we solve the Prisoners' Dilemma game for general N2 N \ge 2 . We find a new property for the game that for an even number of players the payoffs at the Nash equilibrium are equal, whereas for an odd number of players the cooperating players receive higher payoffs.Comment: 26 pages, 2 figure

    Sex-biased parental care and sexual size dimorphism in a provisioning arthropod

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    The diverse selection pressures driving the evolution of sexual size dimorphism (SSD) have long been debated. While the balance between fecundity selection and sexual selection has received much attention, explanations based on sex-specific ecology have proven harder to test. In ectotherms, females are typically larger than males, and this is frequently thought to be because size constrains female fecundity more than it constrains male mating success. However, SSD could additionally reflect maternal care strategies. Under this hypothesis, females are relatively larger where reproduction requires greater maximum maternal effort – for example where mothers transport heavy provisions to nests. To test this hypothesis we focussed on digger wasps (Hymenoptera: Ammophilini), a relatively homogeneous group in which only females provision offspring. In some species, a single large prey item, up to 10 times the mother’s weight, must be carried to each burrow on foot; other species provide many small prey, each flown individually to the nest. We found more pronounced female-biased SSD in species where females carry single, heavy prey. More generally, SSD was negatively correlated with numbers of prey provided per offspring. Females provisioning multiple small items had longer wings and thoraxes, probably because smaller prey are carried in flight. Despite much theorising, few empirical studies have tested how sex-biased parental care can affect SSD. Our study reveals that such costs can be associated with the evolution of dimorphism, and this should be investigated in other clades where parental care costs differ between sexes and species
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