7,521 research outputs found

    Spectral Weights, d-wave Pairing Amplitudes, and Particle-hole Tunneling Asymmetry of a Strongly Correlated Superconductor

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    The spectral weights (SW's) for adding and removing an electron of the Gutzwiller projected d-wave superconducting (SC) state of the t-J-type models are studied numerically on finite lattices. Restrict to the uniform system but treat exactly the strong correlation between electrons, we show that the product of weights is equal to the pairing amplitude squared, same as in the weakly coupled case. In addition, we derive a rigorous relation of SW with doping in the electron doped system and obtain particle-hole asymmetry of the conductance-proportional quantity within the SC gap energy and, also, the anti-correlation between gap sizes and peak heights observed in tunneling spectroscopy on high Tc cuprates.Comment: 4 Revtex pages and 4 .eps figures. Published versio

    Ultrafast dynamics of a magnetic antivortex - Micromagnetic simulations

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    The antivortex is a fundamental magnetization structure which is the topological counterpart of the well-known magnetic vortex. We study here the ultrafast dynamic behavior of an isolated antivortex in a patterned Permalloy thin-film element. Using micromagnetic simulations we predict that the antivortex response to an ultrashort external field pulse is characterized by the production of a new antivortex as well as of a temporary vortex, followed by an annihilation process. These processes are complementary to the recently reported response of a vortex and, like for the vortex, lead to the reversal of the orientation of the antivortex core region. In addition to its fundamental interest, this dynamic magnetization process could be used for the generation and propagation of spin waves for novel logical circuits.Comment: 4 pages, 4 figures. To be published in Physical Review B (R

    Myeloid suppressor cell depletion augments antitumor activity in lung cancer.

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    BackgroundMyeloid derived suppressor cells (MDSC) are important regulators of immune responses. We evaluated the mechanistic role of MDSC depletion on antigen presenting cell (APC), NK, T cell activities and therapeutic vaccination responses in murine models of lung cancer.Principal findingsIndividual antibody mediated depletion of MDSC (anti-Gr1 or anti-Ly6G) enhanced the antitumor activity against lung cancer. In comparison to controls, MDSC depletion enhanced the APC activity and increased the frequency and activity of the NK and T cell effectors in the tumor. Compared to controls, the anti-Gr1 or anti-Ly6G treatment led to increased: (i) CD8 T cells, (ii) NK cells, (iii) CD8 T or NK intracytoplasmic expression of IFNγ, perforin and granzyme (iv) CD3 T cells expressing the activation marker CD107a and CXCR3, (v) reduced CD8 T cell IL-10 production in the tumors (vi) reduced tumor angiogenic (VEGF, CXCL2, CXCL5, and Angiopoietin1&2) but enhanced anti-angiogenic (CXCL9 and CXCL10) expression and (vii) reduced tumor staining of endothelial marker Meca 32. Immunocytochemistry of tumor sections showed reduced Gr1 expressing cells with increased CD3 T cell infiltrates in the anti-Gr1 or anti-Ly6G groups. MDSC depletion led to a marked inhibition in tumor growth, enhanced tumor cell apoptosis and reduced migration of the tumors from the primary site to the lung compared to controls. Therapeutic vaccination responses were enhanced in vivo following MDSC depletion with 50% of treated mice completely eradicating established tumors. Treated mice that rejected their primary tumors acquired immunological memory against a secondary tumor challenge. The remaining 50% of mice in this group had 20 fold reductions in tumor burden compared to controls.SignificanceOur data demonstrate that targeting MDSC can improve antitumor immune responses suggesting a broad applicability of combined immune based approaches against cancer. This multifaceted approach may prove useful against tumors where MDSC play a role in tumor immune evasion

    Optical trapping using ultrashort 12.9fs pulses

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    We demonstrate stable three-dimensional optical trapping of 780nm silica particles using a dispersion-compensated 12.9fs infrared pulsed laser and a trapping microscope system with 1.40NA objective. To achieve these pulse durations we use the Multiphoto

    現代化中家庭結構和功能的改變 : 對北京、香港和雲南家庭的研究 = Are impacts of modernization on family in structure and function universal? A study among Beijing, Hong Kong and Yunnan families

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    框架 --背景介绍 --“现代化”的定义 --现代化对家庭的影响 --结论和讨论 Contents --Background --Definition of Modernization --Modernization and Its Impacts on Family --Conclusion and Discussio

    Resolving inter-particle position and optical forces along the axial direction using optical coherence gating

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    We demonstrate the use of coherence gating to resolve particle positions and forces in the axial direction. High depth resolvability (axial) and weak optical force (10-15 N) measurements in an optical trapping system is achieved
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