2,752 research outputs found

    Apatite Formation Abilities and Mechanical Properties of Hydroxyethylmethacrylate-based Organic-inorganic Hybrids Incorporated with Sulfonic Groups and Calcium Ions

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    Apatite formation in the living body is an essential requirement for artificial materials to exhibit bone-bonding bioactivity. It has been recently revealed that sulfonic groups trigger apatite nucleation in a body environment. Organic–inorganic hybrids consisting of organic polymers and the sulfonic groups are therefore expected to be useful for preparation of novel bone-repairing materials exhibiting flexibility as well as bioactivity. In the present study, organic–inorganic hybrids were prepared from hydroxyethylmethacrylate (HEMA) in the presence of vinylsulfonic acid sodium salt (VSAS) and calcium chloride (CaCl2). The bioactivities of the hybrids were assessed in vitro by examining the apatite formation in simulated body fluid (SBF, Kokubo solution). The hybrids deposited on the apatite after soaking in SBF within 7 days. Tensile strength measurements showed a tendency to increase with increases in VSAS and CaCl2 content. It was assumed that this phenomenon was attributed to the formation of cross-linking in the hybrids

    Holographic Penta and Hepta Quark State in Confining Gauge Theories

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    We study a new embedding solutions of D5 brane in an asymptotic AdS5×S5{}_5\times S^5 space-time, which is dual to a confining SU(Nc)SU(N_c) gauge theory. The D5 brane is wrapped on S5S^5 as in the case of the vertex of holographic baryon. However, the solution given here is different from the usual baryon vertex in the point that it couples to kk-anti-quarks and Nc+kN_c+k quarks on the opposite two points of S5S^5, the north and south poles, respectively. The total quark number of this state is preserved as NcN_c when minus one is assigned to anti-quark, then it forms a color singlet like the baryon. However, this includes anti-quarks and quarks, whose number is larger than that of the baryon. When we set as Nc=3N_c=3, we find the so called penta and hepta-quark states. We study the dynamical properties of these states by solving the vertex and string configurations for such states. The mass spectra of these states and the tension of the stretched vertex are estimated, and they are compared with that of the baryon.Comment: 24 pages, 6 figure

    Apatite Formation Abilities and Mechanical Properties of Hydroxyethylmethacrylate-based Organic-inorganic Hybrids Incorporated with Sulfonic Groups and Calcium Ions

    Get PDF
    Apatite formation in the living body is an essential requirement for artificial materials to exhibit bone-bonding bioactivity. It has been recently revealed that sulfonic groups trigger apatite nucleation in a body environment. Organic–inorganic hybrids consisting of organic polymers and the sulfonic groups are therefore expected to be useful for preparation of novel bone-repairing materials exhibiting flexibility as well as bioactivity. In the present study, organic–inorganic hybrids were prepared from hydroxyethylmethacrylate (HEMA) in the presence of vinylsulfonic acid sodium salt (VSAS) and calcium chloride (CaCl2). The bioactivities of the hybrids were assessed in vitro by examining the apatite formation in simulated body fluid (SBF, Kokubo solution). The hybrids deposited on the apatite after soaking in SBF within 7 days. Tensile strength measurements showed a tendency to increase with increases in VSAS and CaCl2 content. It was assumed that this phenomenon was attributed to the formation of cross-linking in the hybrids

    Mass-loaded spherical accretion flows

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    We have calculated the evolution of spherical accretion flows undergoing mass-loading from embedded clouds through either conduction or hydrodynamical ablation. We have observed the effect of varying the ratios of the mass-loading timescale and the cooling timescale to the ballistic crossing timescale through the mass-loading region. We have also varied the ratio of the potential energy of a particle injected into the flow near the outer region of mass-loading to the temperature at which a minimum occurs in the cooling curve. The two types of mass-loading produce qualitatively different types of behaviour in the accretion flow, since mass-loading through conduction requires the ambient gas to be hot, whereas mass ablation from clumps occurs throughout the flow. Higher ratios of injected to accreted mass typically occur with hydrodynamical ablation, in agreement with previous work on wind-blown bubbles and supernova remnants. We find that mass-loading damps the radiative overstability of such flows, in agreement with our earlier work. If the mass-loading is high enough it can stabilize the accretion shock at a constant radius, yielding an almost isothermal subsonic post-shock flow. Such solutions may be relevant to cooling flows onto massive galaxies. Mass-loading can also lead to the formation of isolated shells of high temperature material, separated by gas at cooler temperatures

    New Gauged Linear Sigma Models for 8D HyperKahler Manifolds and Calabi-Yau Crystals

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    We propose two kinds of gauged linear sigma models whose moduli spaces are real eight-dimensional hyperKahler and Calabi-Yau manifolds, respectively. Here, hyperKahler manifolds have sp(2) holonomy in general and are dual to Type IIB (p,q)5-brane configurations. On the other hand, Calabi-Yau fourfolds are toric varieties expressed as quotient spaces. Our model involving fourfolds is different from the usual one which is directly related to a symplectic quotient procedure. Remarkable features in newly-found three-dimensional Chern-Simons-matter theories appear here as well, such as dynamical Fayet-Iliopoulos parameters, one dualized photon and its residual discrete gauge symmetry.Comment: 20 pages, 1 figure; v2: minor changes and references added; v3: statements improved, newer than JHEP versio

    Complete set of polarization transfer coefficients for the 3He(p,n){}^{3}{\rm He}(p,n) reaction at 346 MeV and 0 degrees

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    We report measurements of the cross-section and a complete set of polarization transfer coefficients for the 3He(p,n){}^{3}{\rm He}(p,n) reaction at a bombarding energy TpT_p = 346 MeV and a reaction angle θlab\theta_{\rm lab} = 00^{\circ}. The data are compared with the corresponding free nucleon-nucleon values on the basis of the predominance of quasi-elastic scattering processes. Significant discrepancies have been observed in the polarization transfer DLL(0)D_{LL}(0^{\circ}), which are presumably the result of the three-proton TT = 3/2 resonance. The spin--parity of the resonance is estimated to be 1/21/2^-, and the distribution is consistent with previous results obtained for the same reaction at TpT_p = 48.8 MeV.Comment: 4 figures, Accepted for publication in Physical Review

    Intersecting Noncommutative D-branes and Baryons in Magnetic Fields

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    We study supersymmetric intersecting configurations of D-branes with B-field backgrounds. Noncommutative D-brane or M-brane pairs can intersect supersymmetrically over (p-1)-brane, as well as over (p-2)-brane like ordinary branes. d=10 and d=11 supergravity solutions are obtained and the supersymmetry projection rule is examined. As an application we study a noncommutative D7-brane probe in noncommutative D3-brane background, intersecting at noncommutative plane, which describes BPS baryons of noncommutative gauge theory in the context of AdS/CFT correspondence.Comment: 15 pages;several important references are added and typos correcte
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