A Mg-Gd-Y-Zn-Zr magnesium alloy with different initial states was extruded under different extrusion parameters.The effect of solution treatment and extrusion parameters on the microstructure,texture and mechanical pr...A Mg-Gd-Y-Zn-Zr magnesium alloy with different initial states was extruded under different extrusion parameters.The effect of solution treatment and extrusion parameters on the microstructure,texture and mechanical properties were analyzed in detail,and the abnormal texture formation and strengthening mechanism was revealed.When extruded at low temperature and small extrusion ratio,the bimodal microstructure consisting of fine dynamically recrystallized grains and coarse deformed grains occurred both in the as-cast alloy and solution-treated alloy.When the extrusion temperature and extrusion ratio were increased,the amount and size of dynamically recrystallized grains increased and the grain size of the solution-treated alloy showed higher growth rate.Furthermore,an abnormal texture with<0001>parallel with extrusion direction developed due to the occurrence of non-basal slip and continuous dynamic recrystallization.This could be enhanced by solution treatment,high temperature,and large extrusion ratio.Both the as-cast alloy and solution-treated alloy exhibited the highest tensile strength after extrusion at 300℃with an extrusion ratio of 9.Grain refinement was the main strengthening mechanism utilized in both the as-cast alloy and the solution-treated alloy.Work hardening played an important role in the sample extruded at low temperature and small extrusion ratio,with the highest contribution of about 33 MPa after extrusion at 300℃with an extrusion ratio of 9.Texture strengthening contributed more in the sample extruded at high temperature and large extrusion ratio,but no more than 24.1 MPa.Solution strengthening was another strengthening mechanism in the extruded as-cast alloy,especially at high temperature and large extrusion ratio(no more than 9 MPa).展开更多
Spinal cord injury(SCI)causes motor,sensory and automatic impairment due to rarely axon regeneration.Developing effective treatment for SCI in the clinic is extremely challenging because of the restrictive axonal rege...Spinal cord injury(SCI)causes motor,sensory and automatic impairment due to rarely axon regeneration.Developing effective treatment for SCI in the clinic is extremely challenging because of the restrictive axonal regenerative ability and disconnection of neural elements after injury,as well as the limited systemic drug delivery efficiency caused by blood spinal cord barrier.To develop an effective non-invasive treatment strategy for SCI in clinic,we generated an autologous plasma exosome(AP-EXO)based biological scaffold where AP-EXO was loaded with neuron targeting peptide(RVG)and growth-facilitating peptides(ILP and ISP).This scaffold can be targeted delivered to neurons in the injured area and elicit robust axon regrowth across the lesion core to the levels over 30-fold greater than naïve treatment,thus reestablish the intraspinal circuits and promote motor functional recovery after spinal cord injury in mice.More importantly,in ex vivo,human plasma exosomes(HP-EXO)loaded with combinatory peptides of RVG,ILP and ISP showed safety and no liver and kidney toxicity in the application to nude SCI mice.Combining the efficacy and safety,the AP-EXO-based personalized treatment confers functional recovery after SCI and showed immense promising in biomedical applications in treating SCI.It is helpful to expand the application of combinatory peptides and human plasma derived autologous exosomes in promoting regeneration and recovery upon SCI treatment.展开更多
基金the National Natural Science Foundation of China(Nos.51775137 and 51875127)。
文摘A Mg-Gd-Y-Zn-Zr magnesium alloy with different initial states was extruded under different extrusion parameters.The effect of solution treatment and extrusion parameters on the microstructure,texture and mechanical properties were analyzed in detail,and the abnormal texture formation and strengthening mechanism was revealed.When extruded at low temperature and small extrusion ratio,the bimodal microstructure consisting of fine dynamically recrystallized grains and coarse deformed grains occurred both in the as-cast alloy and solution-treated alloy.When the extrusion temperature and extrusion ratio were increased,the amount and size of dynamically recrystallized grains increased and the grain size of the solution-treated alloy showed higher growth rate.Furthermore,an abnormal texture with<0001>parallel with extrusion direction developed due to the occurrence of non-basal slip and continuous dynamic recrystallization.This could be enhanced by solution treatment,high temperature,and large extrusion ratio.Both the as-cast alloy and solution-treated alloy exhibited the highest tensile strength after extrusion at 300℃with an extrusion ratio of 9.Grain refinement was the main strengthening mechanism utilized in both the as-cast alloy and the solution-treated alloy.Work hardening played an important role in the sample extruded at low temperature and small extrusion ratio,with the highest contribution of about 33 MPa after extrusion at 300℃with an extrusion ratio of 9.Texture strengthening contributed more in the sample extruded at high temperature and large extrusion ratio,but no more than 24.1 MPa.Solution strengthening was another strengthening mechanism in the extruded as-cast alloy,especially at high temperature and large extrusion ratio(no more than 9 MPa).
基金This work was supported by the National Key Research and Development Project of Stem Cell and Transformation Research(2019YFA0112100),ChinaNational Natural Science Foundation of China(81930070)+3 种基金National Natural Science Foundation of China(82102560)the Natural Science Foundation of Shandong Province,China(ZR2021QH097)the No.69 General Fund of China Postdoctoral Science Foundation(2021M691936)Talent project of Shandong University(22480082063100),China.
文摘Spinal cord injury(SCI)causes motor,sensory and automatic impairment due to rarely axon regeneration.Developing effective treatment for SCI in the clinic is extremely challenging because of the restrictive axonal regenerative ability and disconnection of neural elements after injury,as well as the limited systemic drug delivery efficiency caused by blood spinal cord barrier.To develop an effective non-invasive treatment strategy for SCI in clinic,we generated an autologous plasma exosome(AP-EXO)based biological scaffold where AP-EXO was loaded with neuron targeting peptide(RVG)and growth-facilitating peptides(ILP and ISP).This scaffold can be targeted delivered to neurons in the injured area and elicit robust axon regrowth across the lesion core to the levels over 30-fold greater than naïve treatment,thus reestablish the intraspinal circuits and promote motor functional recovery after spinal cord injury in mice.More importantly,in ex vivo,human plasma exosomes(HP-EXO)loaded with combinatory peptides of RVG,ILP and ISP showed safety and no liver and kidney toxicity in the application to nude SCI mice.Combining the efficacy and safety,the AP-EXO-based personalized treatment confers functional recovery after SCI and showed immense promising in biomedical applications in treating SCI.It is helpful to expand the application of combinatory peptides and human plasma derived autologous exosomes in promoting regeneration and recovery upon SCI treatment.
