Search

In this study, by using periodic pile rows (PPRs) as an example, a new finite element method, namely, the periodic 2.5D finite element method (P2.5D FEM) is developed for the periodic structure embedded in soil. Similar to the 2.5D FEM, the major advantage of the proposed P2.5D FEM is its ability to reduce the 3-D dynamic problem associated with the periodic soil-structure system to a series of 2-D problems. The considered PPR-soil system, referred to as the periodic pile-soil system (PPSS) subsequently is supposed to be subjected to a harmonic point load. To develop the P2.5D FEM for the PPSS, the harmonic point load is decomposed into its wavenumber domain components first. The response of the PPSS to each wavenumber domain load component is then resolved into a series of pseudo plane waves propagating along the z-direction. The quantities for the pseudo plane wave are discretized by the FEM along the cross-section of the PPSS, and the FEM equations for the pseudo plane waves are then established. The eigenequation for the pseudo plane waves can be developed with the aforementioned FEM equations. Summation of the eigenvectors of the eigenequation for the PPSS yields the displacement for the PPSS due to the wavenumber domain load component. Synthesizing the displacements due to all the wavenumber domain load components via the inverse Fourier transform with respect to the wavenumber yields the overall displacement of the PPSS produced by the point load. To show the capability of the proposed P2.5D FEM for the PPSS, some numerical results about the wave barrier effect of PPRs are presented. The developed P2.5D FEM in this study is applicable to the dynamic analysis of various periodic structures embedded in the half-space soil under different types of dynamic loads. [ABSTRACT FROM AUTHOR]

In this study, a longitudinal equivalent periodic shell (LEPS) model and corresponding continuous joint model are proposed for the periodically jointed lining (PJL) tunnel. Based on the LEPS model for the PJL tunnel, an analytical method for the PJL tunnel under seismic waves is established. The surrounding soil of the PJL tunnel is assumed to be the poroelastic medium, and described by the Biot's theory. The lining of the PJL tunnel is assumed to be composed of a series of lining rings linked periodically by ring joints along the longitudinal direction, which are simplified as a LEPS and described by the cylindrical shell theory. Due to the periodicity of the LEPS lining, the tunnel-soil system is treated as a periodic structure in this study. Based on the periodicity condition for the tunnel-soil system as well as the wave function expansion method, the representation for the scattering wave field in the soil is established. By using the aforementioned cylindrical shell theory and Fourier series expansion method, the Fourier space equations of motion and convolution type constitutive relations for the LEPS lining are derived. By using the lining-soil continuity conditions, the Fourier space equations of motion and convolution type constitutive relations for the LEPS lining as well as the representation for the wave field in the soil, the coupled equations for the tunnel-soil system are established, with which the Fourier components of the displacements of the LEPS lining and wave function coefficients for the scattering waves in soil can be solved for. Numerical results indicate that the presence of the ring joint in the LEPS lining of the tunnel will affect the distribution of the internal forces in the lining considerably, and it will also enhance the maximum internal forces occurring in the lining. • The longitudinal equivalent periodic shell (LEPS) model for the shield-driven tunnel is proposed. • The continuous joint model describing the variation of the parameters of the joint along the longitudinal direction of the tunnel is proposed. • The Fourier space convolution type constitutive relation for the LEPS lining of the shield-driven tunnel is developed. • An analytical method for the periodically jointed lining (PJL) tunnel under seismic waves is established. • By using the proposed analytical method for the PJL tunnel, some numerical results for the response of the PJL tunnel to seismic waves are presented. [ABSTRACT FROM AUTHOR]

Abstract In this study, the dynamic response of a periodic viaduct to a moving mass is investigated. In view of the periodicity of the viaduct, the mass-viaduct interaction force is expanded into a Fourier series first, each term of which represents one component of the interaction force. By using the Fourier transform method and finite element method (FEM), the frequency domain response of the periodic viaduct to each interaction force component is obtained. The time domain response of the periodic viaduct to the force component can be recovered by applying the inverse Fourier transform to the corresponding frequency domain response. With the mass-viaduct coupling condition and the time domain response of the viaduct to the force component, the Fourier coefficients of the mass-viaduct interaction force are obtained. Superposing the responses of the periodic viaduct due to all the interaction force components yields the response of the periodic viaduct to the moving mass. Numerical results show that the force-weight ratio increases with increasing mass and speed of the mass, suggesting that the inertial effect of the moving mass should be taken into account for the large mass with high speeds. Also, it is found that for the case of the large moving mass with high speeds, the mass-viaduct interaction force may become negative, indicating that the mass has a tendency to separate from the viaduct in this case. Highlights • A model is developed for the dynamic response of a periodic viaduct to a moving mass. • The convergence of the proposed model is confirmed by numerical simulations and some numerical results are presented. • The occurrence of the negative mass-viaduct interaction force is found by numerical simulations. [ABSTRACT FROM AUTHOR]

Numerical simulations of the dynamic response of the layered soil and embedded structures (LSS) to external loads are important for the design of various infrastructures. In this study, a new wavenumber domain finite element (WDFE) model for the LSS subjected to a concentrated harmonic load is proposed. The layered soil is supposed to be infinite in the horizontal directions and finite in the vertical direction, while the embedded 2-D structures are finite in one horizontal direction and vertical direction. To establish the model, by using the Fourier transform method, the concentrated harmonic load is resolved into wavenumber domain (WD) components first. With the Fourier transform method, the response of the LSS to each WD component of the load is then decomposed into a set of horizontally propagating harmonic waves with the amplitudes depending on the depth. The associated variables for each harmonic wave are then discretized by the FE method along the depth, and the FE equation for each harmonic wave is then derived by the principle of virtual work (PVW). By using the FE equations for the harmonic waves, the eigenvalue equation for the LSS is then deduced. Superposing the eigenvectors given by the eigenvalue equation yields the response of the LSS to the WD component of the load. Synthetization of the responses of the LSS to all WD components of the load via the inverse Fourier transform yields the overall response of the LSS to the concentrated load. To show the capacity of the proposed WDFE model, some numerical results are presented. • A new wavenumber domain finite element (WDFE) model for the layered soil and embedded structures (LSS) is proposed. • Decomposition of the response of the LSS into horizontal harmonic waves avoids the FEM discretization of the LSS along the direction. • The WD convolution form constitutive relation for the LSS is developed in this study. • The FE equation for the horizontally propagating harmonic wave of the LSS is established. • The contour integral method for inversion of the Fourier transform with respect to the WD load component of the external load is proposed. [ABSTRACT FROM AUTHOR]

The dynamic analysis of the pile-reinforced composite foundation (PCF) under seismic waves is important for the design of the PCF and corresponding upper structures. Owing to huge number of degrees of freedom (DOFs) in the modeling, it is still difficult to simulate the dynamic response of the PCF to seismic waves directly by means of traditional numerical methods. To overcome this difficulty, the PCF is simplified as the periodic pile-reinforced composite foundation (PPCF) in this study, and the harmonic wave finite element (HWFE) model for the PPCF under seismic waves is proposed. To establish the HWFE model, the response of the PPCF is decomposed into a series of horizontally propagating harmonic waves with amplitudes varying with the depth. Based on the principle of virtual work (PVW), the finite element method (FEM) equations for each harmonic wave are established. To impose the boundary conditions and input seismic waves at the bottom of the PPCF, the traction-displacement relation at the surface of the underlying half-space bedrock is derived. Solving the FEM equations for the PPCF and synthesizing the resulting solutions for the harmonic waves via the DFT method, dynamic responses of the PPCF to plane harmonic seismic waves are obtained. To verify the developed HWFE model, results obtained by the proposed HWFE model are compared with those by the propagator matrix method (PMM). The numerical results show that the resonance frequency of the PPCF increases with decreasing pile spacing; also, the presence of the stiffer soil layers will enhance the resonance frequency of the PPCF. • The periodic pile-reinforced composite foundation (PPCF) model is proposed. • A harmonic wave finite element (HWFE) model for the PPCF under seismic waves is developed in this study. • The Fourier space convolution form constitutive relation and expression for the inertial force are derived for the PPCF. • The traction-displacement relation at the bedrock surface is derived to input seismic waves at the PPCF bottom. [ABSTRACT FROM AUTHOR]

In this paper, the resonance and cancellation phenomena occurring in a periodic structure-- a pile-supported periodic viaduct subjected to multiple equidistant moving loadings (MEML) are investigated. For this purpose, the representation for the dynamic response of the periodic viaduct to a single moving loading (SML) is introduced first. In order to take account of the pile-soil-structure interaction when evaluating the response of the periodic viaduct to a SML, a wavenumber domain boundary element method (WDBEM) model for the pile-row-soil system is employed to determine the compliances of the piles. By superposing the responses of the viaduct to all SMLs constituting the MEML, the representation for the dynamic response of the periodic viaduct to the MEML is obtained. With the representation for the MEML response of the viaduct, the resonance and cancellation conditions for the viaduct are derived. For the high speed MEML, when the time interval between two neighboring moving loadings is equal to the integer or half-integer multiples of the period of one of the dominant resonance peaks of the corresponding SML response of the viaduct, resonance or cancellation occurs. The predicted resonance and cancellation phenomena are confirmed by the numerical results presented in this paper. [ABSTRACT FROM AUTHOR]

Hematopoietic stem/progenitor cells (HSPCs) are supported and regulated by niche cells in the bone marrow with an important characterization of physiological hypoxia. However, how hypoxia regulates HSPCs is still unclear. Here, we find that meteorin (Metrn) from hypoxic macrophages restrains HSPC mobilization. Hypoxia-induced factor 1α and Yin Yang 1 induce the high expression of Metrn in macrophages, and macrophage-specific Metrn knockout increases HSPC mobilization through modulating HSPC proliferation and migration. Mechanistically, Metrn interacts with its receptor 5-hydroxytryptamine receptor 2b (Htr2b) to regulate the reactive oxygen species levels in HSPCs through targeting phospholipase C signaling. The reactive oxygen species levels are reduced in HSPCs of macrophage-specific Metrn knockout mice with activated phospholipase C signaling. Targeting the Metrn/Htr2b axis could therefore be a potential strategy to improve HSPC mobilization for stem cell-based therapy. [Display omitted] • Deletion of Metrn specifically in macrophages promotes HSPC mobilization by G-CSF • The HIF-1α/YY1 complex induces Metrn expression in macrophages under hypoxia • Metrn is a functional ligand of Htr2 in hematopoietic cells • Metrn regulates HSPC homeostasis by inhibiting the intracellular PLC pathway Dai et al. report an essential role of Metrn in HSPC mobilization. Bone marrow hypoxia maintains the high expression of Metrn in macrophages via HIF-1α/YY1 complex. Metrn regulates HSPC homeostasis by interacting with Htr2b to inhibit HSPC intracellular PLC pathway. These findings elucidate a Metrn/Htr2b axis that controls HSPC mobilization. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a numerical model is developed to investigate the dynamic response of a defected periodic bridge (DPB) when considering pile–soil–water–structure (PSWS) interaction. In order to determine the dynamic response of the DPB, the DPB is decomposed into three parts – left and right semi-infinite periodic bridges and the defected span. To account for the coupling between the superstructure of the bridge and the pile foundations, a coupled boundary element method (BEM) model is used to model the pile–soil–water (PSW) interaction. By using the PSW BEM model, the transfer matrices for the pier and beam, the joint condition at the beam–beam–pier (BBP) junction, the response of the DPB to the characteristic wave is obtained. To investigate the relation between the response of the DPB and the defect state of the corresponding super-cell, the super-cell method is developed for the DPB. Numerical results for the energy bands of the super-cell show that the defected span of the DPB may give rise to additional passband frequencies, namely, the defect state frequencies. Moreover, when the DPB is subjected to a characteristic wave with frequency equal to the defect state frequency, resonance may occur and the response of the DPB corresponding to the resonance is localized around the defected span. [Copyright &y& Elsevier]

Abstract: In this study, a new model is developed for the aseismic design of a periodic viaduct when the pile–soil–structure interaction is considered. To account for the influence of the pile–soil–structure interaction, a wavenumber domain boundary element method (WDBEM) model for the periodic pile row supporting the viaduct is developed using the sequence Fourier transform as well as the boundary element method for the elastic medium. By using the WDBEM model for the pile row, the transfer matrices for the beams and piers, the joint conditions at the beam–beam–pier (BBP) junction as well as the periodicity condition for the viaduct, the wavenumber domain response of the periodic viaduct to spatially harmonic waves is determined. Based on the wavenumber domain response of the viaduct, the space-domain response of the viaduct to an arbitrary seismic wave can be obtained by invoking the inverse sequence Fourier transform method. Numerical results show that when the periodic viaduct is exposed to the spatially harmonic wave, resonances may occur at the bounding frequencies of the passbands of the characteristic waves of the viaduct. Also, it is found that the coincidence between the traveling seismic wave and characteristic waves of the viaduct will generate additional resonant frequencies located in passbands of the characteristic waves. [Copyright &y& Elsevier]

Osteoprotegerin (OPG) is a member of the tumor necrosis factor receptor superfamily, contributing to inflammation, apoptosis, and differentiation. However, the function of OPG in the host immune system of teleosts remains unclear. Here, we cloned the cDNA of the LcOPG gene from large yellow croaker. LcOPG mRNA was expressed in all analyzed tissues and was upregulated by Vibrio alginolyticus infection in immune tissues and monocytes/macrophages (MO/MФ). Subsequently, the LcOPG protein was expressed and purified using a prokaryotic expression system. Recombinant LcOPG protein (rLcOPG) treatment suppressed V. alginolyticus -induced pro-inflammatory cytokine and enhanced V. alginolyticus -induced anti-inflammatory cytokine mRNA expression. Furthermore, rLcOPG decreased V. alginolyticus- induced MO/MФ apoptosis. Therefore, the results indicate that LcOPG might play a role in the immune response of V. alginolyticus- infected large yellow croaker. [Display omitted] • OPG transcripts were altered in large yellow croaker after Vibrio alginolyticus infection. • OPG acts as an anti-inflammatory mediator in V. alginolyticus -infected large yellow croaker MO/MФ. • OPG suppressed V. alginolyticus -induced apoptosis in large yellow croaker MO/MФ. • OPG attenuated NFATc-1 , c-Fos, and Ctsk expression in large yellow croaker MO/MФ. [ABSTRACT FROM AUTHOR]

Direct numerical simulations of the dynamic response of the phononic crystal to point or distributed forces via conventional numerical methods are still formidable currently due to large number of DOFs involved in the simulations. In this study, based on the plane wave expansion (PWE) method, a plane wave finite element (PWFE) model for the 2-D phononic crystal which is infinite in the horizontal direction and finite in the vertical direction and subjected to a point harmonic force is proposed. To this end, the point harmonic force is decomposed into the wavenumber domain (WND) components by the Fourier transform first. The variables of the 2-D phononic crystal under the WND force component are expanded into a series of plane waves along the horizontal direction, and the variables associated with each plane wave are discretized by the FE method in the vertical direction. By using the virtual work principle, FE equations for the plane waves of the phononic crystal are established. With the FE equations for the plane waves, the eigenvalue equation for the displacement of the plane waves and wavenumber is formulated. Superposing the eigenvectors of the above eigenvalue equation yields the displacement for the plane waves due to the WND force component. Synthetization of the contributions from all the plane waves and inversion of the Fourier transform with respect to the wavenumber via the contour integration method generate the response of the phononic crystal to the point force. Comparison of present results with those due to the transfer matrix method validates the proposed model. Also, presented numerical results suggest that the dynamic response of the phononic crystal to a point harmonic force exhibits remarkable resonance phenomenon. • A plane wave finite element (PWFE) model for the 2-D phononic crystal subjected to a point harmonic force is proposed. • The nonlinear eigenvalue equation for the plane wave displacement and wavenumber is derived and linearized. • The model superposition method for constructing the plane wave displacement of the phononic crystal is proposed to avoid direct solution of the FEM equations for the plane wave displacement. • The contour integration method is used to perform the inversion of the Fourier transform with respect to the wavenumber. [ABSTRACT FROM AUTHOR]

Abstract: The influence of the gravity and inertia of a concentrated mass attached to the top of a single pile on the pile’s dynamic response was investigated in this study. Based on Muki’s fictitious pile method, the static initial axial force of the pile caused by the gravity of the concentrated mass was calculated first. Using the obtained initial axial force of the pile and taking into account the influence of the inertia of the concentrated mass, the second kind of Fredholm integral equations describing the dynamic response of the preloaded single pile were established via the fictitious pile method. Using the obtained integral equations, the dynamic response of the preloaded single pile to an incident Rayleigh wave was calculated. The influence of the pile–soil Young’s modulus ratio, the frequency of the incident Rayleigh wave and the pile length on the dynamic response of the preloaded pile was examined. The numerical results of this study show that the concentrated mass attached to the top of the pile will affect both the dynamic axial and shear forces of the pile. Generally, the concentrated mass attached to the pile top has a greater influence on the shear force of the pile than on the axial force. [Copyright &y& Elsevier]

Abstract: In this study, the periodic viaduct is used as an example to introduce a new type of phononic crystal structure: the “open”-type phononic crystal structure. A numerical model for analysis of the energy band of a periodic viaduct undergoing out-of-plane vibration is developed in this study. The most remarkable characteristic of the proposed model for the energy band of the periodic viaduct is that it can take into account the coupling between the periodic viaduct and the half-space soil. The viaduct considered in this study is assumed to be a regularly periodic arrangement of unit cells along its longitudinal direction. For simplicity, each unit cell is assumed to be consisted of a pile foundation, a pier and a horizontal beam. To obtain the compliances for the pile foundations, the pile-soil interaction problem is solved by the fictitious pile method first. Using the transfer matrix method and the obtained compliances for the pile foundations, the impedances for the piers are obtained. Based on the Bloch theorem and the transfer matrix method, the nonlinear polynomial eigenvalue equation for the periodic viaduct is derived using the impedance of the piers. Utilizing the obtained nonlinear eigenvalue equation, the approximate linear eigenvalue equation for the periodic viaduct is obtained and numerical results for the energy bands of the periodic viaduct are presented. Numerical results of this paper show that for the out-of-plane vibration of the periodic viaduct, there are three kinds of lattice waves propagating in the periodic viaduct. Moreover, in a low frequency range, all three lattice waves are evanescent, which will lead to the localization of lattice waves in the periodic viaduct. [Copyright &y& Elsevier]

Abstract: A coupled model is developed to investigate the dynamic interaction between an offshore pile, a porous seabed and seawater when subjected to the pseudo-Stoneley wave along the seabed and the seawater interface. The pile and the seabed are treated as the porous medium governed by Biot''s theory, while the seawater is considered as an acoustic medium and is described by the conventional Helmholtz equation. The free field solution of the incident pseudo-Stoneley wave is obtained using Biot''s theory and the potential method. Based on the boundary element method (BEM) for the porous medium and the acoustic medium, three BEM formulations are constructed for the pile, the seabed and the seawater, respectively, which are combined together using the continuity conditions between the pile, the seabed and the seawater to formulate the coupled model for the system. As shown in numerical examples, when the system is subjected to the pseudo-Stoneley wave, the maximum pore pressure of the seabed usually occurs at the region near the interfaces between the seabed and the seawater. [Copyright &y& Elsevier]

Abstract: A numerical model is developed to analyse the isolation of moving-load induced vibrations using pile rows embedded in a layered poroelastic half-space. Based on Biot’s theory and the transmission and reflection matrices (TRM) method, the free wave field solution for a moving load applied on the surface of a layered poroelastic half-space and the fundamental solution for an harmonic circular patch load are determined. Using Muki and Sternberg’s method, the second kind of frequency domain Fredholm integral equations for the dynamic interaction between pile rows and the layered poroelastic half-space are derived. The time domain solution is recovered via inverse Fourier transform in order to obtain the amplitude reduction ratio and thus assess the vibration isolation efficiency of pile rows. A special case of the present model shows good agreement with an existing solution. Numerical results of this study show that the speed of moving loads has an important influence on the isolation of vibrations by pile rows: the same pile rows can achieve better isolation efficiencies for higher speed loads than for lower speed loads. Pile rows embedded in a two-layered poroelastic half-space with a softer overlying layer usually generate better vibration isolation effects than those with a stiffer overlying layer. Finally, better isolation vibration may be realized by increasing the pile length and decreasing the net spacing between neighboring piles in a pile row. [Copyright &y& Elsevier]

Abstract: Based on the complex variable function method, a new approach for solving the scattering of plane elastic waves by a hole with an arbitrary configuration embedded in an infinite poroelastic medium is developed in the paper. The poroelastic medium is described by Biot''s theory. By introducing three potentials, the governing equations for Biot''s theory are reduced to three Helmholtz equations for the three potentials. The series solutions of the Helmholtz equations are obtained by the wave function expansion method. Through the conformal mapping method, the arbitrary hole in the physical plane is mapped into a unit circle in the image plane. Integration of the boundary conditions along the unit circle in the image plane yields the algebraic equations for the coefficients of the series solutions. Numerical solution of the resulting algebraic equations yields the displacements, the stresses and the pore pressure for the porous medium. In order to demonstrate the proposed approach, some numerical results are given in the paper. [Copyright &y& Elsevier]

Abstract: Based on Biot’s theory, the dynamic 2.5-D Green’s function for a saturated porous medium is obtained using the Fourier transform and the potential decomposition methods. The 2.5-D Green’s function corresponds to the solutions for the following two problems: the point force applied to the solid skeleton, and the dilatation source applied within the pore fluid. By performing the Fourier transform on the governing equations for the 3-D Green’s function, the governing differential equations for the two parts of the 2.5-D Green’s function are established and then solved to obtain the dynamic 2.5-D Green’s function. The derived 2.5-D Green’s function for saturated porous media is verified through comparison with the existing solution for 2.5-D Green’s function for the elastodynamic case and the closed-form 3-D Green’s function for saturated porous media. It is further demonstrated that a simple form 2-D Green’s function for saturated porous media can be been obtained using the potential decomposition method. [Copyright &y& Elsevier]

Abstract: The 3-D boundary integral equation is derived in terms of the reciprocal work theorem and used along with the 2.5-D Green’s function developed in Part I [Lu, J.F., Jeng, D.S., Williams, S., submitted for publication. A 2.5-D dynamic model for a saturated porous medium: Part I. Green’s function. Int. J. Solids Struct.] to develop the 2.5-D boundary integral equation for a saturated porous medium. The 2.5-D boundary integral equations for the wave scattering problem and the moving load problem are established. The Cauchy type singularity of the 2.5-D boundary integral equation is eliminated through introduction of an auxiliary problem and the treatment of the weakly singular kernel is also addressed. Discretisation of the 2.5-D boundary integral equation is achieved using boundary iso-parametric elements. The discrete wavenumber domain solution is obtained via the 2.5-D boundary element method, and the space domain solution is recovered using the inverse Fourier transform. To validate the new methodology, numerical results of this paper are compared with those obtained using an analytical approach; also, some numerical results and corresponding analysis are presented. [Copyright &y& Elsevier]

Abstract: The transmission and reflection matrices (TRM) method for a layered poroelastic half space subjected to moving loads is developed in this study. Applying the triple Fourier transformation, the general solutions for the displacements, the stresses and the pore pressure are derived from the governing equations of Biot’s theory. Utilizing the continuity conditions between each layer and the boundary conditions at the half space surface, the transformed domain solutions for the displacements, the pore pressures and the stresses are established by the transmission and reflection matrices (TRM) method. Numerical results in the time–space domain are obtained by performing the inverse Fourier transform with respect to frequency and the horizontal wavenumbers. Moreover, some numerical examples and corresponding analysis are presented in the paper. Numerical results show that the occurrence of a softer middle layer in the layered half space will enhance the vertical displacement and the pore pressure of the layered half space. Besides, the presence of a softer middle layer tends to make the response of the layered half space exhibit more oscillatory nature. [Copyright &y& Elsevier]

Abstract: Recently, considerable efforts have been devoted to evaluation of seismic dynamic response of a circular tunnel. Conventional approaches have considered integral liners embedded in an elastic medium. In this study, we re-examine the problem with piecewise liners embedded in a porous medium. Surrounding saturated porous medium of tunnels is described by Biot''s poroelastic theory, while the liner pieces and the connecting joints are treated as curved beams and characterized by curved beam theories. The scattered wave field in the porous medium is obtained by the wave function expansion method. The differential equations governing the vibration of a curved beam is discretized by the General Differential Quadrature (GDQ) method. The domain decomposition method is used to establish the global discrete dynamic equations for the piecewise tunnel. The surrounding soil and the tunnel are coupled together via the stress and the displacement continuation conditions which are implemented by the boundary collocation method. Numerical results demonstrate that the stiffness difference between the liner piece and the connecting joints has a considerable influence on the internal forces of the liner piece. [Copyright &y& Elsevier]

Abstract: In this paper, an analytical solution for the dynamic response of a half-space porous medium subjected to a moving point load is derived. In the model, the displacements of the solid skeleton and the pore pressure are expressed in terms of two scalar potentials and one vectorial potential. Based on Biot’s theory, the frequency domain Holmholtz equations for the potentials are derived through the Fourier transformation with respect to time. The general solutions for the potentials are derived through the Fourier transformation with respect to the horizontal coordinates. Numerical results suggest that moving loads have very complicated effects on the dynamic response of the porous medium. Generally speaking, a moving load with a high speed will generate a larger response in the porous medium than a static or a lower speed load. [Copyright &y& Elsevier]

Abstract: In this paper, the frequency domain dynamic response of a pile embedded in a porous medium subjected to SH seismic waves is investigated. The surrounding porous medium of the pile is described by Biot’s poro-elastic theory, while the pile embedded in the porous medium is treated as a beam and described by a beam vibration theory. Using the Hankel transformation method, the fundamental solution for a half-space porous medium subjected to a horizontal circular patch load is established. According to the fictitious pile methodology, the second kind of Fredholm integral equation for the pile is established in terms of the obtained fundamental solution and free wave field. The solution of the integral equation yields the dynamic response of the pile to plane SH waves. Numerical results indicate that the parameters of the porous medium, the pile and incident waves have considerable influences on the dynamic response of the pile and the porous medium. [Copyright &y& Elsevier]

Abstract: A linear isothermal dynamic model for a porous medium saturated by two immiscible fluids is developed in the paper. In contrast to the mixture theory, phase separation is avoided by introducing one energy for the porous medium. It is an important advantage of the model based on one energy approach that it can account for the couplings between the phases. The volume fraction of each phase is characterized by the porosity of the porous medium and the saturation of the wetting phase. The mass and momentum balance equations are constructed according to the generalized mixture theory. Constitutive relations for the stress, pore pressure are derived from the free energy function. A capillary pressure relaxation model characterizing one attenuation mechanism of the two-fluid saturated porous medium is introduced under the constraint of the entropy inequality. In order to describe the momentum interaction between the fluids and the solid, a frequency independent drag force model is introduced. The details of parameter estimation are discussed in the paper. It is demonstrated that all the material parameters in our model can be calculated by the phenomenological parameters, which are measurable. The equations of motion in the frequency domain are obtained in terms of the Fourier transformation. In terms of the equations of motion in the frequency domain, the wave velocities and the attenuations for three P waves and one S wave are calculated. The influences of the capillary pressure relaxation coefficient and the saturation of the wetting phase on the velocities and attenuation coefficients for the four wave modes are discussed in the numerical examples. [Copyright &y& Elsevier]

The focus of this contribution is to develop a hypersingular integral equation method (HIEM) to solve the dynamic interaction between multiple cracks and a circular hole illuminated by plane SH waves. The cracks can be in arbitrary positions; in particular, they can terminate at the boundary of the circular hole. In order to solve the proposed problem, the Green''s function of a point harmonic force applied at an infinite plane with a circular hole is obtained by the Graf formula and the wave function expansion method. In order to construct the hypersingular integral equations for the cracks, the Green''s function is separated into a closed form singular part and a regular part. On the basis of the reciprocity principle as well as the obtained Green''s function, the hypersingular integral equations for the cracks are obtained. Numerical solution of the hypersingular integral equations yields the dynamic stress intensity factors (DSIF) at the crack tips. Comparison of present results with known results verifies the proposed method. Some numerical examples are presented in the paper. [Copyright &y& Elsevier]

Salinity stress have detrimental effect on teleosts and may increase susceptibility to disease. Betaine is a compound utilized by organisms to regulate osmotic pressure and plays an important role in the immune response and anti-inflammatory functions. Here, the protective effects of betaine against Vibrio anguillarum infection of ayu under conditions of salinity was determined. A total of 60 ayu were cultured at 10 ppt salinity for 14 days, all fish were intraperitoneally injected with 100 μL of 100 or 200 mg/kg of betaine or saline on days 0, 2, 4, and 6. The fish were subsequently infected with V. anguillarum. The results showed that betaine treatment improved the survival rate of V. anguillarum -infected ayu. Betaine treatment decreased the bacterial load and histological damage in the head-kidney, liver, and spleen. Besides, the inflammatory response was decreased by betaine in V. anguillarum -infected ayu tissues and monocytes/macrophages (MO/MФ). Furthermore, in hypertonic-exposed MO/MФ (19 mOsm), betaine treatment enhanced phagocytosis activity and promoted the bacterial killing capability. Finally, we found that betaine mediated the inflammatory response through BGT-1 in V. anguillarum- infected ayu MO/MФ. In conclusion, when exposed to osmotic stress, betaine was able to mediate the host defense in ayu and modulate the antibacterial response through MO/MФ. • Betaine administration improved the outcomes of Vibrio anguillarum infected ayu under conditions of salinity. • Betaine administration ameliorated morbidity and histopathological in Vibrio anguillarum infected ayu under salinity. • Betaine mediated antibacterial protection of monocytes/macrophages in ayu under conditions of salinity. • Betaine regulated the function of the hyperosmotic exposure monocytes/macrophages through BGT-1. [ABSTRACT FROM AUTHOR]

Virus-encoded tumor necrosis factor receptors (vTNFRs) facilitate viral escape from the host immune response during viral propagation. Cyprinid Herpesvirus-2 (CyHV-2) is a double-stranded DNA virus of alloherpesviridae family that causes great economic losses in the aquaculture industry. The present study identified and characterized a novel TNFR homolog termed ORF4 in CyHV-2. ORF4 was identified as a secreted protein and a homolog of herpesvirus entry mediator (HVEM). ORF4 localized to the cytoplasm in infected GiCF cells. ORF4 overexpression enhanced viral propagation, while downregulation of ORF4 via siRNA decreased viral propagation. ORF4 overexpression promoted GiCF proliferation, and its downregulation suppressed CyHV-2-induced apoptosis. GST-pulldown and LC-MS/MS assays identified 44 conditional binding proteins that interact with ORF4 protein, while the GST pulldown test did not support the idea that ORF4 interact with histone H3.3. Taken together, our results contribute to our understanding of the vTNFR function in alloherpesviridae pathogenesis and host immune regulation. • CyHV-2-ORF4 was identified as a homolog of herpesvirus entry mediator (HVEM). • ORF4 overexpression enhanced viral propagation. • Downregulation of ORF4 decreased viral propagation. • ORF4 promoted GiCF cell proliferation and suppressed CyHV-2-induced apoptosis. • We identified 44 conditional proteins that might interact with ORF4 protein. [ABSTRACT FROM AUTHOR]

The scattering of elastic waves by a circular hole embedded in the unsaturated soil is investigated in this study. To this end, the mass balance equations, the momentum balance equations, the Biot-type constitutive relations, and the saturation-capillary-pressure relation for the unsaturated soil are used to formulate the differential equations for the independent variables of the unsaturated soil, namely, the displacement of the solid skeleton and the pressures of the pore water and gas. Based on the aforementioned differential equations for the independent variables, the Helmholtz equations for the scalar and vector potentials of the unsaturated soil are established. With the Helmholtz equations for the potentials, the scattered waves of the circular hole are obtained based on the wave function expansion method. By using the boundary conditions of the circular hole, the unknown coefficients in the scattered waves are obtained, and the scattered wave field of the circular hole is thus determined. The Helmholtz equations for the potentials and the potential-variable relations for the unsaturated soil obtained in this study may facilitate solving various dynamic problems of the unsaturated soil. Numerical results of this paper suggest that the stress and pore pressure concentration phenomena caused by low frequency incident waves are more pronounced than those caused by the corresponding static load. Also, for the incident P 1 wave, with increasing saturation, the stress concentration phenomenon becomes less obvious, while that for the pore pressures becomes more pronounced. • The scalar and vector potentials for the unsaturated soil are introduced and corresponding Helmholtz equations are derived. • The representations for the variables of the unsaturated soil by the introduced potentials are established. • With the potential Helmholtz equations, the scattered wave fields of the circular hole for incident plane waves is obtained. • Numerical results and some conclusions about the scattering of elastic waves by the circular hole are presented. [ABSTRACT FROM AUTHOR]

• Integrated observation is used to capture the coseismic signal of rock fracturing. • Fracture process of rock mass of the Baihetan Hydropower Station is studied. • The microfracture, rupture and deformation of rock mass develop synergistically. During the excavation of deep rock engineering projects under high geostress, the brittle failure of hard rock often occurs. To understand the excavation-induced fracturing process of the surrounding rock of a large underground powerhouse, in situ observation schemes have been proposed, including microseismic (MS) monitoring, imaging with a digital panoramic borehole camera, multipoint extensometer measurements and on-site surrounding rock failure investigation. First, a MS system is used to capture the microfractures inside the rock mass, revealing the potential high-risk failure regions. The spatial distribution of MS events shows that the excavation-induced MS events are progressively clustered in the upstream spandrel and downstream foot of the powerhouse, approximately parallel to the direction of the maximum principal stress. Second, the digital panoramic borehole camera and multipoint extensometer are arranged in the high-risk region to further reflect the rock mass fracture evolution and deformation response characteristics in the monitored section. The borehole camera observations of the top arch and sidewall indicate that the excavation unloading not only causes surrounding rock fracturing near the periphery of the cavern but also induces deep fracturing at a certain depth from the periphery of the cavern. From these comprehensive observation results, the mechanism of rock mass mechanical behaviour is clarified; that is, the macroscopic deformation or failure characteristics of the surrounding rock are directly related to the evolution of microfractures. The research results of this paper are valuable for the stability analysis and excavation optimization of similar underground caverns. [ABSTRACT FROM AUTHOR]

• We characterized two CXCR4 genes from Japanese sea bass, Lateolabrax japonica. • CXCR4 transcripts were altered in Japanese sea bass upon Vibrio harveyi infection. • Knockdown of CXCR4a inhibited the expression of IgM in LPS stimulated B cells. • Knockdown of CXCR4a decreased the level of reactive oxygen species in B cells. CXC chemokine receptor 4 (CXCR4), a member of the G-protein-coupled receptor family, plays an important role in host immune responses. Within the teleost lineage, there are two paralogs of CXCR4; however, the role of CXCR4 in teleost B cells is poorly understood. In this study, we determined the cDNA sequences of the two CXCR4 paralogs from the Japanese sea bass (Lateolabrax japonica ; LjCXCR4a and LjCXCR4b). Sequence and phylogenetic tree analyses revealed that LjCXCR4a and LjCXCR4b are most closely related to CXCR4a and CXCR4b, respectively, in the large yellow croaker (Larimichthys crocea). CXCR4 transcripts were mainly expressed in the gills, and their expression in different tissues was altered upon infection with Vibrio harveyi. LjCXCR4a and LjCXCR4b protein levels were upregulated in infected B cells. Knockdown of LjCXCR4a and LjCXCR4b in B cells by RNA interference, the phagocytic activity of B cells was not affected. Furthermore, knockdown of LjCXCR4a, not of LjCXCR4b, was observed to inhibit LjIgM expression in lipopolysaccharide-stimulated B cells. In addition, knockdown of LjCXCR4a, not of LjCXCR4b, was found to reduce reactive oxygen species levels in B cells. Our results indicate that LjCXCR4a and LjCXCR4b modulate the immune response of Japanese sea bass B cells against bacterial infection, albeit via different pathways. [ABSTRACT FROM AUTHOR]

Urocortin (UCN) is a hormone in the hypothalamic–pituitary–adrenal axis that is expressed in various immune cells. However, the function of teleost UCN in the immune system remains unclear. In this study, we cloned the cDNA sequence of UCN from ayu Plecoglossus altivelis (PaUCN). Sequence and phylogenetic tree analyses showed that PaUCN clustered within the fish UCN 1 group and was most related to the rainbow trout (Oncorhynchus mykiss) UCN. PaUCN was expressed in all tested tissues and its expression increased in the liver, spleen, head kidney, and gill upon Vibrio anguillarum infection. Mature PaUCN protein (mPaUCN) treatment affected the phagocytosis and bacterial killing of monocytes/macrophages (MO/MФ). mPaUCN reduced pro-inflammatory cytokine expression in MO/MФ, which was partially mediated via interaction with ayu interleukin-6. mPaUCN reduced bacterial load and increased the survival of V. anguillarum -infected ayu. Overall, UCN as an endocrine factor regulates the immune response of ayu after infection by activating MO/MФ, thus contributing to enhance fish survival. • We characterized a UCN gene from ayu, Plecoglossus altivelis. • UCN improved the phagocytosis and of bacterial killing of monocytes/macrophages. • UCN interacted with IL-6 to inhibit inflammation in monocytes/macrophages. [ABSTRACT FROM AUTHOR]

• We characterized two PU.1 genes from ayu, Plecoglossus altivelis. • The PU.1 transcripts were altered in ayu upon Vibrio anguillarum infection. • PaPU.1a knockdown decreased inflammatory cytokine expression. • PaPU.1b knockdown attenuated MO/MФ bacterial killing capability. Transcription factor PU.1 is a regulator of macrophage function, however, the specific function of PU.1 in teleost monocytes/macrophages (MO/MФ) remains unknown. We determined the cDNA sequence of two PU.1 genes from ayu (Plecoglossus altivelis ; PaPU.1a and PaPU.1b). Sequence comparisons showed that PaPU.1 were most closely related to the PU.1 of rainbow smelt (Osmerus mordax). The PU.1 transcripts were mainly expressed in the spleen, and their expression was altered in various tissues upon infection with Vibrio anguillarum. PaPU.1a and PaPU.1b proteins were upregulated in MO/MФ, after infection. RNA interference was employed to knockdown PaPU.1a and PaPU.1b to investigate their function in MO/MФ. The expression of inflammatory cytokines was regulated by PaPU.1a, but not PaPU.1b, in ayu MO/MФ upon V. anguillarum infection. Both PaPU.1a and PaPU.1b knockdown lowered the phagocytic activity of MO/MФ. Furthermore, PaPU.1b knockdown attenuated MO/MФ bacterial killing capability. Our results indicate that two PaPU.1 genes differentially modulate the immune response in ayu MO/MФ against bacterial infection. [ABSTRACT FROM AUTHOR]

Adrenergic receptors (ARs) are members of the G-protein-coupled receptor superfamily that can be categorized into αARs and βARs. The specific function of ARs in teleost monocytes/macrophages (MO/MФ) remains unknown. We determined the cDNA sequence of ARs from ayu (Plecoglossus altivelis ; PaαAR and PaβAR). Sequence comparisons showed that PaαAR was most closely related to the αAR of the Japanese flounder and Nile tilapia, while PaβAR was most closely related to the βAR of Atlantic salmon. The AR transcripts were mainly expressed in the spleen, and their expression was altered in various tissues upon infection with Vibrio anguillarum. PaαAR and PaβAR proteins were upregulated in MO/MФ after infection, and PaβAR knockdown resulted in a pro-inflammatory status in ayu MO/MФ upon V. anguillarum infection and lowered the phagocytic activity of MO/MФ. Our results indicate that PaβAR plays the role of an anti-inflammatory mediator in the immune response of ayu against bacterial infection. • We characterized ARs gene from ayu, Plecoglossus altivelis. • ARs transcripts were altered in ayu upon Vibrio anguillarum infection. • PaβAR activation promoted the phagocytosis of ayu moncytes/macrophages. • PaβAR acts as an anti-inflammatory mediator in Vibrio anguillarum infected ayu MO/MФ. [ABSTRACT FROM AUTHOR]

[Display omitted] Histone demethylation is a kind of epigenetic modification mediated by a variety of enzymes and participates in regulating multiple physiological and pathological events. Lysine-specific demethylase 7A is a kind of α-ketoglutarate- and Fe(II)-dependent demethylase belonging to the PHF2/8 subfamily of the JmjC demethylases. KDM7A is mainly localized in the nucleus and contributes to transcriptional activation via removing mono- and di-methyl groups from the lysine residues 9 and 27 of Histone H3. Mounting studies support that KDM7A is not only necessary for normal embryonic, neural, and skeletal development, but also associated with cancer, inflammation, osteoporosis, and other diseases. Herein, the structure of KDM7A is described by comparing the similarities and differences of its amino acid sequences of KDM7A and other Histone demethylases; the functions of KDM7A in homeostasis and dyshomeostasis are summarized via documenting its content and related signaling; the currently known KDM7A-specific inhibitors and their structural relationship are listed based on their structure optimization and pharmacological activities; and the challenges and opportunities in exploring functions and developing targeted agents of KDM7A are also prospected via presenting encountered problems and potential solutions, which will provide an insight in functional exploration and drug discovery for KDM7A-related diseases. [ABSTRACT FROM AUTHOR]

Matrix metalloproteinases (MMPs) are highly expressed in leukocytes and macrophages, which play a role in the innate immune response. Here, the cDNA sequence of MMP25 from Japanese sea bass (Lateolabrax japonicus) (LjMMP25) was identified. Phylogenetic analysis revealed that LjMMP25 was most closely related to large yellow croaker MMP25. Multiple sequence alignment of LjMMP25 with MMP25 sequences from other teleosts revealed that regions of known functional importance were highly conserved. Expression analysis revealed that LjMMP25 was highly expressed in the head kidney and widely expressed in other tissues including gill, spleen, and liver. LjMMP25 was found to regulate inflammatory cytokine production and promote phagocytosis and bacterial killing in monocytes/macrophages (MO/MФ). Furthermore, LjMMP25 regulated the inflammatory response by modulating NF-κB signaling. These findings reveal new information about the role of LjMMP25 in regulating pro-inflammatory responses in this species. • We characterized MMP25 gene from Japanese sea bass, Lateolabrax japonicus. • LjMMP25 improved the phagocytosis and bacterial killing of MO/MФ. • LjMMP25 regulated the pro-inflammatory response by NF-κB signaling in MO/MФ. [ABSTRACT FROM AUTHOR]

Lysine-specific demethylase 5A (KDM5A, also named RBP2 or JARID1A) is a demethylase that can remove methyl groups from histones H3K4me1/2/3. It is aberrantly expressed in many cancers, where it impedes differentiation and contributes to cancer cell proliferation, cell metastasis and invasiveness, drug resistance, and is associated with poor prognosis. Pharmacological inhibition of KDM5A has been reported to significantly attenuate tumor progression in vitro and in vivo in a range of solid tumors and acute myeloid leukemia. This review will present the structural aspects of KDM5A, its role in carcinogenesis, a comparison of currently available approaches for screening KDM5A inhibitors, a classification of KDM5A inhibitors, and its potential as a drug target in cancer therapy. [Display omitted] • KDM5A is a Fe(II)- and α-ketoglutaric acid (2-OG)-dependent histone specific demethylase, which can remove methyl groups from histones H3K4me1/2/3. • KDM5A contributes to cancer cell proliferation, cell metastasis and invasiveness, drug resistance, and is associated with poor prognosis. • KDM5A inhibitors exhibited significantly anti-cancer activity in vitro and in vivo in a range of solid tumors and acute myeloid leukemia. [ABSTRACT FROM AUTHOR]

Due to the lack of relevant therapies for infectious haematopoietic necrosis virus (IHNV) infection, the viral outbreak invariably causes serious economic losses in salmonid species. In this study, we evaluated the anti-IHNV effects of 7-(6-benzimidazole) coumarin (C10) and 4-phenyl-2-thioxo-1,2,3,4-tetrahydro-5H-chromeno[4,3-d]pyrimidin-5-one (S5) in vitro and in vivo. The results revealed that C10 at 12.5 mg/L and S5 at 25 mg/L significantly inhibited IHNV replication in epithelioma papulosum cyprini (EPC) cells with a maximum inhibitory rate >90%, showing that IHNV-induced cytopathic effect (CPE) was alleviated by C10 and S5. There are two complementary effects on antiviral mechanism: 1. C10 completely inhibited IHNV infectivity when the virus was preincubated with C10 at 12.5 mg/L, determining that C10 may have a negative impact on IHNV binding to the cell; 2. C10 also up-regulated the gene expression of extracellular proto type galectin-1 (Gal1-L2) and a chimera galectin-3 (Gal3-L1) of EPC cells to inhibit IHNV adhesion. For the in vivo study, injection and immersion of the coumarins enhanced the survival rate of rainbow trout (Oncorhynchus mykiss) juveniles by 25% (at least) at 12 dpi. IHNV loads in the kidney and spleen were also obviously decreased at 96 h, and thus we considered that they had a delaying effect on IHNV replication in vivo. Meanwhile, C10 with a high stability in aquacultural water in immersion suppressed IHNV horizontal transmission by decreasing the viral loads in recipient fish. Overall, our data suggest that there is a positive effect of C10 and S5 against IHNV infection in aquaculture, and C10 had the potential to be a broad-spectrum antiviral against fish rhabdoviruses. • C10 is a potential broad-spectrum antiviral for controlling rhabdovirus. • C10 and S5 have a delaying effect against IHNV replication in vivo. • C10 may reduce the risk of IHNV transmission. • C10 inhibits IHNV adhesion to cell surface. [ABSTRACT FROM AUTHOR]

Hypoxia-inducible factor-1α (HIF-1α) plays a critical role in immune and inflammatory responses and is important in controlling a variety of processes in monocytes and macrophages. However, the role of HIF-1α in the teleost immune system remains less known. In this study, we cloned the cDNA sequence of HIF-1α from the ayu (Plecoglossus altivelis , PaHIF-1α). Sequence and phylogenetic tree analysis showed that PaHIF-1α clustered within the fish HIF-1α tree and was closely related to that of Northern pike (Esox lucius). PaHIF-1α was expressed in all tested tissues and expression increased in liver, head kidney, and body kidney upon Vibrio anguillarum infection. PaHIF-1α was found to regulate the expression of cytokines in ayu monocytes/macrophages (MO/MФ). PaHIF-1α mediated hypoxia-induced enhancement of MO/MФ phagocytic and bactericidal activities to enhance host defenses. Compared with the control, intermittent hypoxia further increased the expression of PaHIF-1α mRNA, improved the survival rate, and reduced the bacterial load of V. anguillarum -infected ayu. Therefore, PaHIF-1α may play a predominant role in the modulation of ayu MO/MФ function. [Display omitted] • We characterized a HIF-1α gene from ayu, Plecoglossus altivelis. • Tissue HIF-1α levels were increased upon Vibrio anguillarum infection. • HIF-1α exerted bactericidal effects on monocytes/macrophages through cathelicidin. • Intermittent hypoxia increased ayu survival after infection through HIF-1α. [ABSTRACT FROM AUTHOR]