18,174 research outputs found

    Phase transitions in Ising model induced by weight redistribution on weighted regular networks

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    In order to investigate the role of the weight in weighted networks, the collective behavior of the Ising system on weighted regular networks is studied by numerical simulation. In our model, the coupling strength between spins is inversely proportional to the corresponding weighted shortest distance. Disordering link weights can effectively affect the process of phase transition even though the underlying binary topological structure remains unchanged. Specifically, based on regular networks with homogeneous weights initially, randomly disordering link weights will change the critical temperature of phase transition. The results suggest that the redistribution of link weights may provide an additional approach to optimize the dynamical behaviors of the system.Comment: 6 pages, 5 figure

    Depth of pleated surfaces in toroidal cusps of hyperbolic 3-manifolds

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    Let FF be a closed essential surface in a hyperbolic 3-manifold MM with a toroidal cusp NN. The depth of FF in NN is the maximal distance from points of FF in NN to the boundary of NN. It will be shown that if FF is an essential pleated surface which is not coannular to the boundary torus of NN then the depth of FF in NN is bounded above by a constant depending only on the genus of FF. The result is used to show that an immersed closed essential surface in MM which is not coannular to the torus boundary components of MM will remain essential in the Dehn filling manifold M(γ)M(\gamma) after excluding CgC_g curves from each torus boundary component of MM, where CgC_g is a constant depending only on the genus gg of the surface

    Ultrasound-targeted microbubble destruction enhances AAV mediated gene transfection: human RPE cells in vitro and the rat retina in vivo

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    The present study was performed to investigate the efficacy and safety of Ultrasound-targeted microbubble destruction (UTMD) mediated rAAV2-EGFP to cultured human retinal pigment epithelium (RPE) cells _in vitro_ and the rat retina _in vivo_. _In vitro_ study, cultured human RPE cells were exposed to US under different conditions with or without microbubbles. Furthermore, the effect of UTMD to rAAV2-EGFP itself and the cells were evaluated. _In vivo_ study, gene transfer was examined by injecting rAAV2-EGFP into the subretinal space of the rats with or without microbubbles and then exposed to US. We investigated EGFP expression _in vivo_ via stereomicroscopy and performed quantitative analysis by Axiovision 3.1 software. HE staining and frozen sections were used to observe tissue damage and location of EGFP gene expression. _In vitro_ study, the transfection efficiency of rAAV2-EGFP increased 74.85% under the optimal UTMD conditions. Furthermore, there was almost no cytotoxicity to the cells and rAAV2-EGFP itself. _In vivo_ study, UTMD could be used safely to enhance and accelerate transgene expression of the retina. Fluorescence expression was mainly located in the layer of retina. UTMD is a promising method for gene delivery to the retina
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