158 research outputs found

    Contribution of biomimetic collagen-ligand interaction to intrafibrillar mineralization

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    Contemporary models of intrafibrillar mineralization mechanisms are established using collagen fibrils as templates without considering the contribution from collagen-bound apatite nucleation inhibitors. However, collagen matrices destined for mineralization in vertebrates contain bound matrix proteins for intrafibrillar mineralization. Negatively charged, high\u2013molecular weight polycarboxylic acid is cross-linked to reconstituted collagen to create a model for examining the contribution of collagen-ligand interaction to intrafibrillar mineralization. Cryogenic electron microscopy and molecular dynamics simulation show that, after cross-linking to collagen, the bound polyelectrolyte caches prenucleation cluster singlets into chain-like aggregates along the fibrillar surface to increase the pool of mineralization precursors available for intrafibrillar mineralization. Higher-quality mineralized scaffolds with better biomechanical properties are achieved compared with mineralization of unmodified scaffolds in polyelectrolyte-stabilized mineralization solution. Collagen-ligand interaction provides insights on the genesis of heterogeneously mineralized tissues and the potential causes of ectopic calcification in nonmineralized body tissues

    Relation Between Chiral Susceptibility and Solutions of Gap Equation in Nambu--Jona-Lasinio Model

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    We study the solutions of the gap equation, the thermodynamic potential and the chiral susceptibility in and beyond the chiral limit at finite chemical potential in the Nambu--Jona-Lasinio (NJL) model. We give an explicit relation between the chiral susceptibility and the thermodynamic potential in the NJL model. We find that the chiral susceptibility is a quantity being able to represent the furcation of the solutions of the gap equation and the concavo-convexity of the thermodynamic potential in NJL model. It indicates that the chiral susceptibility can identify the stable state and the possibility of the chiral phase transition in NJL model.Comment: 21 pages, 6 figures, misprints are correcte

    Prunella vulgaris: A comprehensive review of chemical constituents, pharmacological effects and clinical applications.

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    Prunella vulgaris (PV) is a perennial herb belonging to the Labiate family and is widely distributed in northeastern Asian countries such as Korea, Japan, and China. It is reported to display diverse biological activities including anti-microbial, anti-cancer, and anti-inflammation as determined by in vitro or in vivo studies. So far, about 200 compounds have been isolated from PV plant and majority of these have been characterized mainly as triterpenoids, sterols and flavonoids, followed by coumarins, phenylpropanoids, polysaccharides and volatile oils. This review summarizes and analyzes the current knowledge on the chemical constituents, pharmacological activities, mechanisms of action and clinical applications of the PV plant including its potential as a future medicinal plant. Although some of the chemical constituents of the PV plant and their mechanism of action have been investigated the biological activities of many of these remain unknown and further clinical trials are required to further enhance its reputation as a medicinal plant

    Performance evaluation of bidirectional MB-OFDM UWB over cable, MMF and SMF

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    10.1109/MWSYM.2009.5165707IEEE MTT-S International Microwave Symposium Digest357-360IMID

    Natural vibration of cantilever porous twisted plate with variable thickness in different directions

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    In this paper, the blade is assumed to be a rotating variable thickness cantilever twisted plate structure, and the natural vibrations of variable thickness cantilever twisted plate made of metal porous material are studied. It is assumed that the thickness of the plate changes along spanwise direction and chordwise direction, respectively, and it changes in both directions. The classical thin shell theory, the first and second fundamental forms of surface and von Karman geometric relationship are employed to derive the total potential energy and kinetic energy of the cantilever twisted plate, in which the centrifugal force potential due to high rotational speed is included. Then, according to the Rayleigh-Ritz procedure and applying the polynomial functions which satisfy the cantilever boundary conditions, the dynamic system expressed by equations of motion is reduced to an eigenvalue problem. By numerical simulation, the frequency curves and the mode shapes of the twisted plate can be obtained to reveal the internal connection between natural vibration and the parameters. A series of comparison studies are performed to verify the accuracy of the present formulation and calculations, in which compared data come from experimental, finite element method and theoretical calculation, respectively. The influence of pre-twist angle, three different forms of thickness taper ratio and rotational speed on natural vibration, mode exchange and frequency veering phenomenon of the system is discussed in detail. In addition, the approach proposed here can efficiently extract analytical expressions of mode functions for rotating variable thickness cantilever twisted plate structures
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