Cells actively sense and transduce microenvironmental mechanical inputs into chemical signals via cytoskeletal rearrangements.During these mechanosensation and mechanotransduction processes,the role of the actin cytos...Cells actively sense and transduce microenvironmental mechanical inputs into chemical signals via cytoskeletal rearrangements.During these mechanosensation and mechanotransduction processes,the role of the actin cytoskeleton is well-understood,whereas the role of the tubulin cytoskeleton remains largely elusive.Here,we report the dynamic changes in microtubules in response to microenvironmental stiffness during chondrocyte mitosis.Mechanical stiffness was found to be coupled with microtubule generation,directing microtubule dynamics in mitotic chondrocytes.Refilin B was found to be a key regulator of microtubule assembly in chondrocytes in response to mechanical stiffness.It was found to play its role in microtubule formation via the p-Smad3 signaling pathway.Additionally,integrin-linked kinase(ILK),triggered by mechanical stiffness,was found to play an indispensable role in the process of microtubule dynamics mediated by refilin B.Our data emphasizes stiffness-mediated dynamic changes in the microtubules of chondrocytes in a quiescent state(G0)and at anaphase,which improves our understanding of the mechanical regulation of microtubule assembly during the chondrocyte cell cycle and provides insights into microenvironment mechanics during tissue maintenance,wound healing,and disease occurrence.展开更多
Titanosilicate zeolites are an important class of heterogeneous catalysts that are widely used in several catalytic processes.The construction of hierarchical titanosilicate zeolites(e.g.,TS-1 with an MFI structure)is...Titanosilicate zeolites are an important class of heterogeneous catalysts that are widely used in several catalytic processes.The construction of hierarchical titanosilicate zeolites(e.g.,TS-1 with an MFI structure)is of great interest as they can promote the mass transportation and molecular accessibility of reactant molecules.Herein,we presented a temperature-regulated method to construct anatase-free hierarchical TS-1 zeolite catalysts by utilizing a two-step hydrothermal crystallization strategy with tetrabutylammonium hydroxide(TBAOH)as the sole organic structure-directing agent.The two-step crystallization process,i.e.,initial crystallization at lower temperature followed by secondary crystallization at higher temperature,afforded the incorporation of more active Ti species into TS-1 and the formation of hierarchical structures resulting from the layer-stacking growth.The prepared hierarchical TS-1 zeolite catalysts showed superior catalytic performance in the oxidative desulfurization of bulky organosulfur compound dibenzothiophene compared with their microporous counterpart,giving a higher turnover number(23.5 vs.1.7).The temperature-based kinetic regulation approach offers an effective way to construct hierarchical titanosilicate zeolite catalysts with controllable active Ti atoms.展开更多
This study investigates the effect of nonuniform heating and temperature-dependent viscosity on transient free convective flow in a porous material adjacent to a semi-infinite upright plate.Such scenarios are relevant...This study investigates the effect of nonuniform heating and temperature-dependent viscosity on transient free convective flow in a porous material adjacent to a semi-infinite upright plate.Such scenarios are relevant to applications such as the cooling of electronic devices,solar energy systems,and geophysical processes.The governing equations are transformed into dimensionless form and subsequently solved using the CrankNicolson technique.The results reveal that velocity increases with increasing viscosity parameter(ζ=0,2,4)at all cross-sections,while the temperature decreases at x=0.25 and 0.5,but rises at x=0.75,with the maximum free-stream velocity occurring at x=0.75 forζ=2.Additionally,velocity and temperature attain their highest values near the plate,with the boundary layers growing over time.Eventually,both velocity and temperature stabilize,signifying the attainment of a steady-state condition.The local Nusselt number exhibits an increasing trend with increasing Darcy,Prandtl,and Grashof numbers,indicating improved heat transfer,while increasing viscosity contributes to a reduction in local skin friction.Moreover,nonuniform heating leads to the highest temperature at x=0.5,which decreases at x=0.75,and reaches its lowest value at x=0.25.展开更多
CONSPECTUS:Additive Manufacturing(AM)technology produces three-dimensional components in a layer-by-layer fashion and offers numerous advantages over conventional manufacturing processes.Driven by the growing needs of...CONSPECTUS:Additive Manufacturing(AM)technology produces three-dimensional components in a layer-by-layer fashion and offers numerous advantages over conventional manufacturing processes.Driven by the growing needs of diverse industrial sectors,this technology has seen significant advances on both scientific and engineering fronts.Fusion-based processes are the mainstream techniques for AM of metallic materials.As the metals go through melting and solidification during the printing processes,the final microstructure and hence the properties of the printed components are highly sensitive to the printing conditions and can be very different from those of the feedstock.It is critical to understand the process-microstructure-property relationship for the accelerated optimization of the processing conditions and certification of the printed components.While experimentation has been used widely to acquire a mechanistic understanding of this subject matter,numerical modeling has become increasingly helpful in achieving the same purpose.In this Account,the authors review their ongoing collaborative effort to establish a multiphysics modeling framework to predict the process-microstructure-property relationship in fusion-based metal AM processes.The framework includes three individual modules to simulate the dominating physics that dictate the process dynamics and microstructure evolution during printing as well as the responses of the printed microstructure to specific mechanical loadings.The process model uses the material properties and processing conditions as the inputs and simulates the laser-material interaction,multiphase thermo-fluid flow,and fluid-driven powder motion.It has successfully revealed the physical causes of depression zone shape variation as well as powder motion during the laser powder bed fusion process.The microstructure model uses the thermal history of the printing process and the material chemistry as the inputs and predicts the nucleation and growth of multiple grains in the multipass and multilayer printing processes.It has been used to understand the effects of inoculation and thermal conditions on grain texture evolution.The property models use microstructure data from simulations,experimental measurements,or statistical analyses as the inputs and leverage various computational tools to predict the mechanical response of the AM materials.These models have been used to quantitatively evaluate the effects of grain structure,residual strain,and pore and void defects on their properties and performance.While this and many other modeling works have significantly grown our collective knowledge of the process-microstructure-property relationship in fusion-based metal AM processes,efforts should be further invested in developing advanced theories and algorithms for the governing physics,leveraging data-driven approaches,accelerating simulation speed,and calibrating/validating models with controlled experimental measurements,among other aspects.展开更多
基金supported by the National Natural Science Foundation of China(grant numbers 81771047 to J.X.,11932014,12372315 to X.L.,and 82273837 to L.S.)Sichuan Science and Technology Innovation Talent Project(2022JDRC0044)。
文摘Cells actively sense and transduce microenvironmental mechanical inputs into chemical signals via cytoskeletal rearrangements.During these mechanosensation and mechanotransduction processes,the role of the actin cytoskeleton is well-understood,whereas the role of the tubulin cytoskeleton remains largely elusive.Here,we report the dynamic changes in microtubules in response to microenvironmental stiffness during chondrocyte mitosis.Mechanical stiffness was found to be coupled with microtubule generation,directing microtubule dynamics in mitotic chondrocytes.Refilin B was found to be a key regulator of microtubule assembly in chondrocytes in response to mechanical stiffness.It was found to play its role in microtubule formation via the p-Smad3 signaling pathway.Additionally,integrin-linked kinase(ILK),triggered by mechanical stiffness,was found to play an indispensable role in the process of microtubule dynamics mediated by refilin B.Our data emphasizes stiffness-mediated dynamic changes in the microtubules of chondrocytes in a quiescent state(G0)and at anaphase,which improves our understanding of the mechanical regulation of microtubule assembly during the chondrocyte cell cycle and provides insights into microenvironment mechanics during tissue maintenance,wound healing,and disease occurrence.
基金the National Key Research and Development Program of China(Grant 2016YFB0701100)the National Natural Science Foundation of China(Grant 21920102005,21621001,and 21835002)+2 种基金the 111 Project of China(B17020)for supporting this workThe support from National Major Scientific Instruments and Equipments Development Project of National Natural Science Foundation of China(Grant 2152780065)is also acknowledgedR.B.also acknowledges the Graduate Interdisciplinary Research Funding of Jilin University(10183201815).
文摘Titanosilicate zeolites are an important class of heterogeneous catalysts that are widely used in several catalytic processes.The construction of hierarchical titanosilicate zeolites(e.g.,TS-1 with an MFI structure)is of great interest as they can promote the mass transportation and molecular accessibility of reactant molecules.Herein,we presented a temperature-regulated method to construct anatase-free hierarchical TS-1 zeolite catalysts by utilizing a two-step hydrothermal crystallization strategy with tetrabutylammonium hydroxide(TBAOH)as the sole organic structure-directing agent.The two-step crystallization process,i.e.,initial crystallization at lower temperature followed by secondary crystallization at higher temperature,afforded the incorporation of more active Ti species into TS-1 and the formation of hierarchical structures resulting from the layer-stacking growth.The prepared hierarchical TS-1 zeolite catalysts showed superior catalytic performance in the oxidative desulfurization of bulky organosulfur compound dibenzothiophene compared with their microporous counterpart,giving a higher turnover number(23.5 vs.1.7).The temperature-based kinetic regulation approach offers an effective way to construct hierarchical titanosilicate zeolite catalysts with controllable active Ti atoms.
文摘This study investigates the effect of nonuniform heating and temperature-dependent viscosity on transient free convective flow in a porous material adjacent to a semi-infinite upright plate.Such scenarios are relevant to applications such as the cooling of electronic devices,solar energy systems,and geophysical processes.The governing equations are transformed into dimensionless form and subsequently solved using the CrankNicolson technique.The results reveal that velocity increases with increasing viscosity parameter(ζ=0,2,4)at all cross-sections,while the temperature decreases at x=0.25 and 0.5,but rises at x=0.75,with the maximum free-stream velocity occurring at x=0.75 forζ=2.Additionally,velocity and temperature attain their highest values near the plate,with the boundary layers growing over time.Eventually,both velocity and temperature stabilize,signifying the attainment of a steady-state condition.The local Nusselt number exhibits an increasing trend with increasing Darcy,Prandtl,and Grashof numbers,indicating improved heat transfer,while increasing viscosity contributes to a reduction in local skin friction.Moreover,nonuniform heating leads to the highest temperature at x=0.5,which decreases at x=0.75,and reaches its lowest value at x=0.25.
基金support provided by the National Science Foundation under Grant No.CMMI-2119671.
文摘CONSPECTUS:Additive Manufacturing(AM)technology produces three-dimensional components in a layer-by-layer fashion and offers numerous advantages over conventional manufacturing processes.Driven by the growing needs of diverse industrial sectors,this technology has seen significant advances on both scientific and engineering fronts.Fusion-based processes are the mainstream techniques for AM of metallic materials.As the metals go through melting and solidification during the printing processes,the final microstructure and hence the properties of the printed components are highly sensitive to the printing conditions and can be very different from those of the feedstock.It is critical to understand the process-microstructure-property relationship for the accelerated optimization of the processing conditions and certification of the printed components.While experimentation has been used widely to acquire a mechanistic understanding of this subject matter,numerical modeling has become increasingly helpful in achieving the same purpose.In this Account,the authors review their ongoing collaborative effort to establish a multiphysics modeling framework to predict the process-microstructure-property relationship in fusion-based metal AM processes.The framework includes three individual modules to simulate the dominating physics that dictate the process dynamics and microstructure evolution during printing as well as the responses of the printed microstructure to specific mechanical loadings.The process model uses the material properties and processing conditions as the inputs and simulates the laser-material interaction,multiphase thermo-fluid flow,and fluid-driven powder motion.It has successfully revealed the physical causes of depression zone shape variation as well as powder motion during the laser powder bed fusion process.The microstructure model uses the thermal history of the printing process and the material chemistry as the inputs and predicts the nucleation and growth of multiple grains in the multipass and multilayer printing processes.It has been used to understand the effects of inoculation and thermal conditions on grain texture evolution.The property models use microstructure data from simulations,experimental measurements,or statistical analyses as the inputs and leverage various computational tools to predict the mechanical response of the AM materials.These models have been used to quantitatively evaluate the effects of grain structure,residual strain,and pore and void defects on their properties and performance.While this and many other modeling works have significantly grown our collective knowledge of the process-microstructure-property relationship in fusion-based metal AM processes,efforts should be further invested in developing advanced theories and algorithms for the governing physics,leveraging data-driven approaches,accelerating simulation speed,and calibrating/validating models with controlled experimental measurements,among other aspects.
