Search

Abstract: In this paper, the flux and separation factor for water/ethanol mixtures in PVA membrane system are detected and a modified solution-diffusion model is proposed to account for the mass transport of penetrants in the polymer membrane. In the model, the group contribution method (the UNIFAC-ZM model) is introduced to calculate the activity of penetrants in the polymer membrane, and a modified Fujita temperature-dependence diffusion coefficient equation is developed to describe the diffusion behavior of the penetrants. The aim of this work is to establish a predictive solution-diffusion model. As an exemplary application of the model, the permeation fluxes and separation factors of water/ethanol mixtures in PVA membrane system have been predicted and showed to be in good agreement with experimental values. [Copyright &y& Elsevier]

Abstract: The electrolyte model LIQUAC has been used up till now to predict osmotic coefficients, mean ion activity coefficients, the vapor–liquid equilibrium (VLE) behavior, the solubility of gases in single and mixed solvent electrolyte systems, and solubilities of salts in aqueous solutions. In this paper, the required expressions for the calculation of salt solubilities not only in aqueous systems, but also in organic solvents and water–solvent electrolyte systems were deduced in detail based on the LIQUAC model with a fixed reference state and thermodynamic relations. Four salts (NaCl, KCl, NH4Cl and NaF) and two solvent (water and methanol) were selected to test the derived expressions. The results show that the LIQUAC model with a fixed reference state can be used to predict osmotic coefficients, solubilities of salts in aqueous solutions, vapor–liquid equilibria, and the solubilities of salts in water–organic solvent systems with strong electrolytes. [Copyright &y& Elsevier]

A new rectangular concrete-filled hot-rolled-steel tubular flat column (RCSTFC) constructed from hot-rolled steel and internal steel plates was proposed in this study. The influence of the internal steel plate thickness (T I), angle steel thickness (T a), and cell number on the axial compression performance of RCSTFCs was investigated. The test results showed that RCSTFCs exhibit overall instability and local buckling under axial compression. Under D / B = 2.0, 2.67 and 3.0, the changes in T I , T a and cell number did not significantly influence the failure mode, strength index or axial deformation ductility of RCSTFCs with the same steel ratio. Furthermore, the area of the effectively confined zone and the stress-strain relationship of the confined concrete in the RCSTFCs were deduced, and a new calculation method for the axial load-carrying capacity of RCSTFCs was proposed. Compared to the design methods in GB 50936, CECS 159, AS 5100.6, and AISC 360, the proposed method produced relatively accurate results in the prediction of the axial load-carrying capacity of RCSTFCs. • RCSTFC configuration was studied by axial compression test. • Confined area and stress-strain relationship of concrete in RCSTFC were deduced. • New calculation method of RCSTFC axial load-carrying capacity was proposed. [ABSTRACT FROM AUTHOR]

• Flexural performance of CWFBs with CHCSs was verified by out-of-plane flexural tests. • The CWFBs with CHCSs had shear lag effects in both the tension and compression zones. • The effect of loading method and slab width on CWFB effective width was analyzed. • The equation to calculate the effective width of the CWFB was deduced theoretically. To investigate the flexural performance and effective flange width of composite wide flat beams (CWFBs) with composite hollow core slabs (CHCSs), four CWFB specimens with double-sided CHCSs were tested and analyzed. The test results indicated that all specimens showed typical flexural damage. The CWFB with CHCSs had shear lag effect in both tension and compression zones. Increasing the width of the CHCSs resulted in a greater effective width, stiffness, and load carrying capacity of CWFB with CHCSs. Compared with the three-point loading method, the effective width of CWFB with CHCSs was larger for the four-point loading method and the uniform loading method. In addition, finite element models (FEMs) of the tested specimens in MSC. Marc software were validated by the test results, and 30 FEMs were further analyzed. Finally, the equations for calculating the effective width were obtained for the CWFB with CHCSs under uniform, four-point and three-point loads. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tenogenic patch can promote the tendon-like morphology, adhesion, proliferation and migration of tendon fibroblasts in vitro. • The tenogenic patch enhanced the collagen fiber regeneration in the acute rotator cuff tear model. • The patch scaffold can strengthen tendon and the regeneration of tendon-to-bone insertion. Rotator cuff tear of shoulder is a common tendon injury. Current therapeutic strategies are unsatisfactory because of poor biomechanical properties of the repaired rotator cuff tendons. To solve this problem, a newly biofabricated tenogenic patch by uniaxial cold-drawing technology was applied for the treatment of acute rotator cuff tear and its therapeutic effects were evaluated in vitro and in vivo. The cytocompatibility results indicated that the engineered patch was capable of promoting the spreading, migration and proliferation of tendon fibroblasts in vitro. Stress–strain curves of the sutured patch indicated improved elasticity followed by the yield phenomena, nonlinear plasticity and obviously delaminated rupture. The tenogenic patch also showed significantly enhanced collagen I deposition and better tendon-to-bone healing in the rat rotator cuff tear models in vivo. Furthermore, implantation with the tenogenic patch also promoted the fibrocartilage formation in Safranin-O/Fast green-staining. The analysis of biomechanical properties showed that the tenogenic patch is capable of improving the ultimate load of the repaired tendon. Therefore, the tenogenic patch may constitute an efficient strategy to enhance tendon-to-bone healing for clinical repair applications of rotator cuff tear. [ABSTRACT FROM AUTHOR]

• This study proposed a SC-CRWBB by introduced BRBs at corner and UPTs at center to CRW. • The seismic performance of SC-CRWBB was studied through the quasi-static tests. • The influence of UPTs initial stress and BRB area on residual drift was analyzed. • The hysteretic curve and the required UPTs initial stress were theoretically deduced. A new self-centering controlled rocking wall (CRW) with buckling-restrained braces (BRBs) at the base (SC-CRWBB) is proposed to improve the energy dissipation and self-centering capacities of CRWs. The SC-CRWBB was established by adding unbonded posttensioned tendons (UPTs) at the center and BRBs at two corners of a CRW. The quasi-static test results demonstrated that the proposed SC-CRWBB achieved a satisfactory seismic performance. Structural damage was concentrated in the BRBs, while a few cracks occurred in the surface between the CRW and mortar layer and between the BRBs and CRW. Then, a finite element model (FEM) of the test specimen was created in ABAQUS software to study the influence of the initial stress of the UPTs and sectional area of the BRB core plate on the residual deformation and lateral carrying capacity of the SC-CRWBB. Finally, an analytical method for the investigation of SC-CRWBBs was validated against the test and FE analysis results. [ABSTRACT FROM AUTHOR]

Abstract: Acellular porcine cornea stroma (APCS) prepared using pancreatic phospholipase A2 was proven to be promising corneal scaffold. However, its dense ultrastructure provides insufficient space that prevents the seeded cells from organizing into a functional tissue. In this report, freezing dry APCS (FD-APCS) biomaterials containing pores with different sizes were fabricated at different pre-freezing temperatures of −10, −80 or −198°C, and the percentage of large pores (equivalent circle diameter≥10μm) was 93.55%, 69.36%, 35.79%, while the small pores (<10μm) were account for 6.45%, 30.64%, 64.21%, respectively. Both porosity and specific surface area increased in FD-APCS fabricated with decreased pre-freezing temperature, and they were dramatically higher than those in APCS. The three FD-APCS groups displayed higher permeability than APCS, and the −10°C FD-APCS possessed the highest permeability. The keratocytes seeded in the FD-APCS construct survived well in vitro, and maximal cell proliferation was observed in the −10°C FD-APCS. The light transmittance of the FD-APCS-transplanted cornea after interlamellar keratoplasty in rabbit eyes displayed no significant difference from the APCS-transplanted or native cornea. This study indicated that the porous FD-APCS prepared using pancreatic phospholipase A2 is capable of serving as potential scaffold for constructing tissue-engineered cornea with biological properties. [Copyright &y& Elsevier]

Abstract: Adult stem cells are important cell sources in regenerative medicine, but isolating them is technically challenging. This study employed a novel strategy to generate stem-like corneal epithelial cells and promote the functional properties of these cells by coculture with embryonic stem cells. The primary corneal epithelial cells were labelled with GFP and cocultured with embryonic stem cells in a transwell or by direct cell–cell contact. The embryonic stem cells were pre-transfected with HSV-tk-puro plasmids and became sensitive to ganciclovir. After 10 days of coculture, the corneal epithelial cells were isolated by treating the cultures with ganciclovir to kill the embryonic stem cells. The expression of stem cell-associated markers (ABCG2, p63) increased whereas the differentiation mark (Keratin 3) decreased in corneal epithelial cells isolated from the cocultures as evaluated by RT-PCR and flow cytometry. Their functional properties of corneal epithelial cells, including cell adhesion, migration and proliferation, were also enhanced. These cells could regenerate a functional stratified corneal epithelial equivalent but did not form tumors. Integrin β1, phosphorylated focal adhesion kinase and Akt were significantly upregulated in corneal epithelial cells. FAK Inhibitor 14 that suppressed the expression of phosphorylated focal adhesion kinase and Akt inhibited cell adhesion, migration and proliferation. LY294002 that suppressed phosphorylated Akt but not phosphorylated focal adhesion kinase inhibited cell proliferation but had no effect on cell adhesion or migration. These findings demonstrated that the functional properties of stem-like corneal epithelial cells were enhanced by cocultured embryonic stem cells via activation of the integrin β1-FAK-PI3K/Akt signalling pathway. [Copyright &y& Elsevier]

• A new type of superimposed reinforced concrete shear wall with insulation is proposed by integrating the insulation panel into the precast exterior concrete panel to achieve both bearing and insulation capabilities. • The connection method of the longitudinal reinforcement at the horizontal joints of the superimposed reinforced concrete shear wall is indirect splicing on one side and direct splicing on the other side, and the direct splicing area is moved upwards to avoid the horizontal joints. A new type of superimposed reinforced concrete shear wall with insulation (SRCSWI) is proposed in this paper by integrating the insulation panel into the precast exterior concrete panel to achieve both bearing and insulation capabilities. Four full-sized specimens, including one cast-in-place reinforced concrete shear wall (CRCSW), two SRCSWIs and one superimposed reinforced concrete shear wall (SRCSW) without insulation, were designed for use in pseudo-static tests. The test results showed that the failure modes of the SRCSWIs were similar to those of the CRCSW and SRCSW. For the SRCSWI with a lower reinforcement ratio for the boundary elements, fewer cracks occurred in the wall, while the opening width of the cracks in the horizontal joints was relatively large, which means that the plastic deformation of this specimen was concentrated near the horizontal joints. For the SRCSWIs, the precast exterior concrete panel contributed little to the stiffness and carrying capacity of the walls. For the SRCSWI specimens, SRCSW specimen and CRCSW specimen with the same design axial load ratio, the stiffness, ductility and carrying capacity were basically consistent. For the SRCSWI specimen with a lower axial force, the carrying capacity was lower, but the ductility ratio and energy dissipation coefficient were higher than those of the other specimens. Finally, solid finite element (FE) models of the test specimens were established in ABAQUS and validated with the experimental results. The distribution of concrete damage, steel reinforcement stress distribution and hysteretic curves in the numerical analysis were basically consistent with the test results. [ABSTRACT FROM AUTHOR]