The implementation of solid-fluid boundary condition has been a major challenge for dissipative particle dynamics(DPD)method.Current implementations of boundary conditions usually try to approach a uniform density dis...The implementation of solid-fluid boundary condition has been a major challenge for dissipative particle dynamics(DPD)method.Current implementations of boundary conditions usually try to approach a uniform density distribution and a velocity profile close to analytical solution.The density oscillations and slip velocity are intentionally eliminated,and different wall properties disappear in the same analytical solution.This paper develops a new wall model that combines image and frozen particles and a new strategy to emphasize different wall properties especially wettabilities.The strategy first studies the realistic wall-fluid system by molecular dynamics(MD)simulation depending on physical parameters.Then,a DPD simulation is used to match the density and velocity profiles with the new wall model.The obtained DPD parameters can simulate the systems with the same wall and fluid materials.With this method,a simulation of the Poiseuille flow of liquid argon with copper walls is presented.Other walls with super-hydrophilic,hydrophilic,and hydrophobic wettabilities are also simulated.The limitations of the analytical solution and the effect of the wall-fluid interaction are discussed.The results show that the method suggested in this paper can simulate the mesoscale behavior of the microchannel flow related to realistic systems.展开更多
How to endow bone grafts with long-term antibacterial activity and good bone regenerative ability to achieve the regenerative repair of infected bone defects has been the focus of the clinical treatment of osteomyelit...How to endow bone grafts with long-term antibacterial activity and good bone regenerative ability to achieve the regenerative repair of infected bone defects has been the focus of the clinical treatment of osteomyelitis.The present study introduced a novel one-step route to realizing the co-doping of zinc oxide(ZnO)and zinc ion(Zn^(2+))in biphasic calcium phosphate(BCP)ceramics to utilize their synergistic antibacterial.Compared with the conventional BCP ceramics(BCP-Ca),the ZnO/Zn^(2+)co-doping ones(BCP-Zn)possessed strong antibacterial ability on E.coli and S.aureus as well as stimulated the osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs)effectively.The synergistic antibacterial mechanism of ZnO and Zn^(2+)was also investigated.BCP-Zn showed excellent osteoinductivity and angiogenesis at three months postoperatively in the canine intramuscular implantation model.Moreover,BCP-Zn exhibited excellent anti-infective ability and bone regenerative repair compared to BCP-Ca and control groups in the infected bone defect model of rat femur.Collectively,these findings suggest that the simultaneous introduction of ZnO/Zn^(2+)could have immense potential to expand the application of osteoinductive BCP ceramics in the regenerative repair of infected bone defects.展开更多
文摘The implementation of solid-fluid boundary condition has been a major challenge for dissipative particle dynamics(DPD)method.Current implementations of boundary conditions usually try to approach a uniform density distribution and a velocity profile close to analytical solution.The density oscillations and slip velocity are intentionally eliminated,and different wall properties disappear in the same analytical solution.This paper develops a new wall model that combines image and frozen particles and a new strategy to emphasize different wall properties especially wettabilities.The strategy first studies the realistic wall-fluid system by molecular dynamics(MD)simulation depending on physical parameters.Then,a DPD simulation is used to match the density and velocity profiles with the new wall model.The obtained DPD parameters can simulate the systems with the same wall and fluid materials.With this method,a simulation of the Poiseuille flow of liquid argon with copper walls is presented.Other walls with super-hydrophilic,hydrophilic,and hydrophobic wettabilities are also simulated.The limitations of the analytical solution and the effect of the wall-fluid interaction are discussed.The results show that the method suggested in this paper can simulate the mesoscale behavior of the microchannel flow related to realistic systems.
基金the National Key Research and Development Program of China(Grant No.2022YFC2401801)National Science Foundation of China(Grant No.52002256)+1 种基金Major Project of Sichuan Science and Technology Department(Grant Nos.2022ZDZX0029 and 2021YFS0032)Sichuan University“Zero to one”Innovation Research Project(Grant No.2022SCUH0044).
文摘How to endow bone grafts with long-term antibacterial activity and good bone regenerative ability to achieve the regenerative repair of infected bone defects has been the focus of the clinical treatment of osteomyelitis.The present study introduced a novel one-step route to realizing the co-doping of zinc oxide(ZnO)and zinc ion(Zn^(2+))in biphasic calcium phosphate(BCP)ceramics to utilize their synergistic antibacterial.Compared with the conventional BCP ceramics(BCP-Ca),the ZnO/Zn^(2+)co-doping ones(BCP-Zn)possessed strong antibacterial ability on E.coli and S.aureus as well as stimulated the osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs)effectively.The synergistic antibacterial mechanism of ZnO and Zn^(2+)was also investigated.BCP-Zn showed excellent osteoinductivity and angiogenesis at three months postoperatively in the canine intramuscular implantation model.Moreover,BCP-Zn exhibited excellent anti-infective ability and bone regenerative repair compared to BCP-Ca and control groups in the infected bone defect model of rat femur.Collectively,these findings suggest that the simultaneous introduction of ZnO/Zn^(2+)could have immense potential to expand the application of osteoinductive BCP ceramics in the regenerative repair of infected bone defects.
