Directional solidification experiments were carried out with Al-Pb alloys under the effect of a direct current （DC）. The experimental results show that the DC causes a migration of the minority phase droplets （MPDs...Directional solidification experiments were carried out with Al-Pb alloys under the effect of a direct current （DC）. The experimental results show that the DC causes a migration of the minority phase droplets （MPDs） from the middle part to the surface region of the sample, Samples with either a finely dispersed microstructure or a shell/ core structure were obtained by solidifying the alloy under the effect of the properly selected DC densities, A model was developed to describe the microstructure evolution in an immiscible alloy directionaliy solidified under the effect of the DC. The microstructure formation in the AI-Pb alloys was calculated. The numerical results are in favorable agreement with the experimental ones. They demonstrate that the DC affects the microstructure formation mainly through changing the spatial motions of the MPDs and the temperature field of the melt in front of the solid/liquid interface. The formation mechanisms of the finely dispersed microstructure as well as the shell/core structure were sufficiently clarified.展开更多
The osteochondral defects(OCDs)resulting from the treatment of giant cell tumors of bone(GCTB)often present two challenges for clinicians:tumor residue leading to local recurrence and non-healing of OCDs.Therefore,thi...The osteochondral defects(OCDs)resulting from the treatment of giant cell tumors of bone(GCTB)often present two challenges for clinicians:tumor residue leading to local recurrence and non-healing of OCDs.Therefore,this study focuses on developing a double-layer PGPC-PGPH scaffold using shell-core structure nanofibers to achieve“spatiotemporal control”for treating OCDs caused by GCTB.It addresses two key challenges:eliminating tumor residue after local excision and stimulating osteochondral regeneration in non-healing OCD cases.With a shell layer of protoporphyrin IX(PpIX)/gelatin(GT)and inner cores containing chondroitin sulfate(CS)/poly(lactic-co-glycolic acid)(PLGA)or hydroxyapatite(HA)/PLGA,coaxial electrospinning technology was used to create shell-core structured PpIX/GT-CS/PLGA and PpIX/GT-HA/PLGA nanofibers.These nanofibers were shattered into nano-scaled short fibers,and then combined with polyethylene oxide and hyaluronan to formulate distinct 3D printing inks.The upper layer consists of PpIX/GT-CS/PLGA ink,and the lower layer is made from PpIX/GT-HA/PLGA ink,allowing for the creation of a double-layer PGPC-PGPH scaffold using 3D printing technique.After GCTB lesion removal,the PGPC-PGPH scaffold is surgically implanted into the OCDs.The sonosensitizer PpIX in the shell layer undergoes sonodynamic therapy to selectively damage GCTB tissue,effectively eradicating residual tumors.Subsequently,the thermal effect of sonodynamic therapy accelerates the shell degradation and release of CS and HA within the core layer,promoting stem cell differentiation into cartilage and bone tissues at the OCD site in the correct anatomical position.This innovative scaffold provides temporal control for anti-tumor treatment followed by tissue repair and spatial control for precise osteochondral regeneration.展开更多
Spiral fibers with high energy storage and high output efficiency are highly desirable for soft robots and actuators.However,it is still a great challenge to achieve spiral fibers with excellent water actuation perfor...Spiral fibers with high energy storage and high output efficiency are highly desirable for soft robots and actuators.However,it is still a great challenge to achieve spiral fibers with excellent water actuation performance,structural stability,and high scalability in a low-cost strategy.A coaxial spiral structure is reported for the fabrication of high-performance fiber actuators.The developed shell-core helical fiber actuators were based on alginate/poly(ethylene glycol)acrylate shell and alginate/GO core with green and excellent spinnability.Owing to the high water-absorbing-swelling capacity and energy storage of the shell,the prepared spiral fibers are characterized by fast response,high energy output,and good repeatability of cycling.On the other hand,the core endows the spiral fibers with the additional features of strong force retention and photothermal response.The shell-core spiral structure promotes the output efficiency of the twisted fiber actuator with a large rotation(2500°/cm),untwisting speed(2250 rpm),and recovery speed(2700 rpm).In addition,the tertiary spiral structure based on TAPG fibers exhibits excellent humidity and photothermal response efficiency.The application of fibers to smart textiles enables efficient human epidermal thermal management.展开更多
基金the financial support from the National Natural Science Foundation of China(Nos. 51071159,51031003,51271185 and u0837601)
文摘Directional solidification experiments were carried out with Al-Pb alloys under the effect of a direct current （DC）. The experimental results show that the DC causes a migration of the minority phase droplets （MPDs） from the middle part to the surface region of the sample, Samples with either a finely dispersed microstructure or a shell/ core structure were obtained by solidifying the alloy under the effect of the properly selected DC densities, A model was developed to describe the microstructure evolution in an immiscible alloy directionaliy solidified under the effect of the DC. The microstructure formation in the AI-Pb alloys was calculated. The numerical results are in favorable agreement with the experimental ones. They demonstrate that the DC affects the microstructure formation mainly through changing the spatial motions of the MPDs and the temperature field of the melt in front of the solid/liquid interface. The formation mechanisms of the finely dispersed microstructure as well as the shell/core structure were sufficiently clarified.
基金supported by the National Natural Science Foundation of China(82302395 and 82001979)Natural Science Foundation of Shanghai(22YF1437400)+6 种基金Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)Shandong Provincial Natural Science Foundation(Major Basic Research Program,ZR2019ZD38)Taishan Scholar Program of Shandong Province(To Huitang Xia,202211333)Natural Science Foundation of Shandong Province(ZR2020MH381)Academic Promotion Program of Shandong First Medical University(2019LJ005)Shandong First Medical University Culture Foundation(202201-09)Social Science Planning and Research Project of Shandong Province(21CTQJ08).
文摘The osteochondral defects(OCDs)resulting from the treatment of giant cell tumors of bone(GCTB)often present two challenges for clinicians:tumor residue leading to local recurrence and non-healing of OCDs.Therefore,this study focuses on developing a double-layer PGPC-PGPH scaffold using shell-core structure nanofibers to achieve“spatiotemporal control”for treating OCDs caused by GCTB.It addresses two key challenges:eliminating tumor residue after local excision and stimulating osteochondral regeneration in non-healing OCD cases.With a shell layer of protoporphyrin IX(PpIX)/gelatin(GT)and inner cores containing chondroitin sulfate(CS)/poly(lactic-co-glycolic acid)(PLGA)or hydroxyapatite(HA)/PLGA,coaxial electrospinning technology was used to create shell-core structured PpIX/GT-CS/PLGA and PpIX/GT-HA/PLGA nanofibers.These nanofibers were shattered into nano-scaled short fibers,and then combined with polyethylene oxide and hyaluronan to formulate distinct 3D printing inks.The upper layer consists of PpIX/GT-CS/PLGA ink,and the lower layer is made from PpIX/GT-HA/PLGA ink,allowing for the creation of a double-layer PGPC-PGPH scaffold using 3D printing technique.After GCTB lesion removal,the PGPC-PGPH scaffold is surgically implanted into the OCDs.The sonosensitizer PpIX in the shell layer undergoes sonodynamic therapy to selectively damage GCTB tissue,effectively eradicating residual tumors.Subsequently,the thermal effect of sonodynamic therapy accelerates the shell degradation and release of CS and HA within the core layer,promoting stem cell differentiation into cartilage and bone tissues at the OCD site in the correct anatomical position.This innovative scaffold provides temporal control for anti-tumor treatment followed by tissue repair and spatial control for precise osteochondral regeneration.
基金the financial support provided by the Fundamental Research Funds for the Central Universities(No.2232023G-04)Shanghai Frontiers Science Center of Advanced Textiles,Donghua University,Shanghai,China.
文摘Spiral fibers with high energy storage and high output efficiency are highly desirable for soft robots and actuators.However,it is still a great challenge to achieve spiral fibers with excellent water actuation performance,structural stability,and high scalability in a low-cost strategy.A coaxial spiral structure is reported for the fabrication of high-performance fiber actuators.The developed shell-core helical fiber actuators were based on alginate/poly(ethylene glycol)acrylate shell and alginate/GO core with green and excellent spinnability.Owing to the high water-absorbing-swelling capacity and energy storage of the shell,the prepared spiral fibers are characterized by fast response,high energy output,and good repeatability of cycling.On the other hand,the core endows the spiral fibers with the additional features of strong force retention and photothermal response.The shell-core spiral structure promotes the output efficiency of the twisted fiber actuator with a large rotation(2500°/cm),untwisting speed(2250 rpm),and recovery speed(2700 rpm).In addition,the tertiary spiral structure based on TAPG fibers exhibits excellent humidity and photothermal response efficiency.The application of fibers to smart textiles enables efficient human epidermal thermal management.
