4,584 research outputs found

    1/4 BPS solutions in massive IIA supergravity

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    We study four kinds of 1/4 BPS solutions in massive IIA supergravity corresponding to D8-D0-F1, D8-D2, D8-D4 and D8-D6-NS5 systems. We show that these solutions are reproduced without making nontrivial assumptions by using supersymmetry conditions. D8-D2 and D8-D4 solutions are represented by harmonic functions, as usual, while the other two are represented by solutions of non-linear differential equations. Because these four solutions can be treated in almost identical ways, we mainly focus on the D8-D6-NS5 systems. We first discuss D6-NS5 solutions with uniform mass parameters. Then, we introduce D8-branes as domain walls by connecting two solutions with different values of the mass parameter. We also discuss boundary conditions and supersymmetry on domain walls.Comment: 19 pages, PTPTeX, typos corrected, reference adde

    Thermal switching rate of a ferromagnetic material with uniaxial anisotropy

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    The field dependence of the thermal switching rate of a ferromagnetic material with uniaxial anisotropy was studied by solving the Fokker-Planck equation. We derived the analytical expression of the thermal switching rate using the mean first-passage time approach, and found that Brown's formula [Phys. Rev. 130, 1677 (1963)] is applicable even in the low barrier limit by replacing the attempt frequency with the proper factor which is expressed by the error function.Comment: 5 pages, 2 figure

    Ricci-flat deformation of orbifolds and localized tachyonic modes

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    We study Ricci-flat deformations of orbifolds in type II theory. We obtain a simple formula for mass corrections to the twisted modes due to the deformations, and apply it to originally tachyonic and massless states in several examples. In the case of supersymmetric orbifolds, we find that tachyonic states appear when the deformation breaks all the supersymmetries. We also study nonsupersymmetric orbifolds C^2/Z_{2N(2N+1)}, which is T-dual to N type 0 NS5-branes. For N>=2, we compute mass corrections for states, which have string scale tachyonic masses. We find that the corrected masses coincide to ones obtained by solving the wave equation for the tachyon field in the smeared type 0 NS5-brane background geometry. For N=1, we show that the unstable mode representing the bubble creation is the unique tachyonic mode.Comment: 20 pages, minor collection

    Salivary histatin 3 inhibits heat shock cognate protein 70–mediated inflammatory cytokine production through toll–like receptors in human gingival fibroblasts.

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    Background: Salivary histatins are bioactive peptides related to the innate immune system associated with antimicrobial activities. However, very little is known about the physiological and biological functions of histatins against host cells or their role in oral cell inflammation. Histatin 3 binds to heat shock cognate protein 70 (HSC70,a constitutively expressed heat shock protein (HSP)). It is unclear whether HSC70 is involved in the inflammatory response in oral cells. Injured oral cells release some intracellular proteins including HSC70. It is possible that released HSC70 induces toll-like receptor (TLR) activation, just as extracellular HSP70 (a stress inducible HSP) does, and that histatin 3 affects this process. Therefore, we tested the hypothesis that HSC70 activates TLR signaling and histatin 3 inhibits this activation and inflammatory cytokine production. Methods: A nuclear factor (NF)-κB-dependent luciferase reporter plasmid was transfected into HEK293 cells stably expressing TLR2 with coreceptor CD14 (293-TLR2/CD14 cells) or stably expressing TLR4 with CD14 and the accessory molecule MD2 (293-TLR4/MD2-CD14 cells). The cells were stimulated with HSC70 in the presence or absence of histatin 3, and examined using luciferase assays. We also stimulated human gingival fibroblasts (HGFs) with HSC70 with or without histatin 3. Then, we analyzed the levels of inflammatory cytokines (interleukin (IL)-6 and IL-8) in the culture media. Cell proteins were analyzed using enzyme-linked immunosorbent assay and Western blotting with antibodies of mitogen-activated protein kinases and NF-κB inhibitor IκB-α, respectively. Histatin 3-bound form of HSC70 was analyzed using limited V8 protease proteolysis. Results: HSC70 induced NF-κB activation in a dose-dependent manner in 293-TLR2/CD14 and 293-TLR4/MD2-CD14 cells, and histatin 3 inhibited this process and when histatin 3 binding to HSC70 was precluded by 15-deoxyspergualin, which augmented NF-κB-triggered activation. In HGFs, histatin 3 also inhibited HSC70-induced inflammatory cytokine production, extracellular signal-regulated protein kinase phosphorylation, and degradation of IκB-α. Moreover, HSC70 inthe presence of histatin 3 was relatively resistant to digestion by V8 protease compared with HSC70 in the presence of control peptide. Conclusions: Histatin 3 may be an inhibitor of HSC70-triggered activation of TLR signaling and inflammatory cytokine production and may be involved in inflammation processes noted in oral cells

    Earth Pressure on Retaining Walls and Buried Pipe

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    This paper describes the results of earth pressure measurements buried pipes. Conventional earth pressure gauges fixed on the walls were type earth pressure gauges which covers the whole wall surface were used components of the resultant earth pressures were measured
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