The bending stiffness of the inflated beam is considered as a constant before wrinkles appear, and it decreases obviously as wrinkles propagate. The formula of the bending stiffness is obtained based on the membrane t...The bending stiffness of the inflated beam is considered as a constant before wrinkles appear, and it decreases obviously as wrinkles propagate. The formula of the bending stiffness is obtained based on the membrane theory in this paper. Furthermore, the definition of dimensionless bending stiffness factor is presented; the relationship of bending stiffness factor and wrinkling factor is derived; the bending stiffness factor is simplified as different linear functions with wrinkling factor, and the simplified model of bending stiffness of inflated beam under bending is also obtained. The bending stiffness including expression of wrinkling factor is substituted into the deflection differential equation, and then the slope and deflection equation of the inflated beam is deduced by integrating the deflection differential equation. Finally, the load-deflection curve is obtained, which is compared with the experimental data in a previous paper. It has a good agreement with each other.展开更多
In the present study,actual three-dimensional structures are converted into a stick model of multi degree of-freedom(MDOF)systems for understanding the macro-behavior of structures.The study investigates the performan...In the present study,actual three-dimensional structures are converted into a stick model of multi degree of-freedom(MDOF)systems for understanding the macro-behavior of structures.The study investigates the performance of three closely spaced,adjacent G+10,fixed-base MDOF systems with the mass aligned at the same levels and subjected to accidental underground blast loading.The acceleration time history of underground blast loading is generated based on past empirical relationships.The blast charge weight varies from 10 to 75 t while keeping the charge distance constant(R=100 m).The entire formulation is solved with the MATLAB solver,using the state space form solution.Three cases are considered,based on changing the position of the three stick systems.The first case considered left building rigid,middle building moderate rigid,and right building flexible.The second assumed left building flexible,middle building rigid,and right building moderate rigid.The third examined the left building as moderate rigid,the middle building as flexible,and the right building rigid.An analysis of the results shows that the arrangement with low stiffness,high stiffness,and moderately stiff buildings placed to the left,middle,and right side,respectively,yields minimum structural response when compared to the other two combinations.展开更多
The technology of induced pluripotent stem cells(iPSCs)has enabled the conversion of somatic cells into primitive undifferentiated cells via reprogramming.This approach provides possibilities for cell replacement ther...The technology of induced pluripotent stem cells(iPSCs)has enabled the conversion of somatic cells into primitive undifferentiated cells via reprogramming.This approach provides possibilities for cell replacement therapies and drug screening,but the potential risk of tumorigenesis hampers its further development and in vivo application.How to generate differentiated cells such as valvular endothelial cells(VECs)has remained a major challenge.Utilizing a combinatorial strategy of selective soluble chemicals,cytokines and substrate stiffness modulation,mouse embryonic fibroblasts are directly and efficiently transdifferentiated into induced aortic endothelial cell-like cells(iAECs),or human primary adult fibroblasts are transdifferentiated into induced valvular endothelial cell-like cells(hiVECs),without expressing pluripotency stem cell markers.These iAECs and hiVECs express VEC-associated genes and proteins and VEC-specific marker NFATC1 and are functional in culture and on decellu-larized porcine aortic valves,like mouse aortic endothelial cells or human primary aortic valvular endothelial cells.The iAECs and hiVECs seeded on decellularized porcine aortic valves stay intact and express VEC-associated proteins for 60 days after grafting into abdominal aorta of immune-compromised rats.In contrast,induced pluripotent stem cells(iPSCs)are less efficient in differentiating into VEC-like cells and pluripotency marker Nanog is expressed in a small subpopulation of iPSC-derived VEC-like cells that generate teratomas in SCID mice whereas hiVECs derived from transdifferentiation do not generate teratomas in vivo.Our findings highlight an approach to efficiently convert fibroblasts into iAECs and hiVECs and seed them onto decellularized aortic valves for safely generating autologous tissue-engineered aortic valves without using viruses or first reprogramming the cells into pluripotent stem cells.展开更多
基金Sponsored by the Program for New Century Excellent Talents in University (Grant No. NCET-08-0150)
文摘The bending stiffness of the inflated beam is considered as a constant before wrinkles appear, and it decreases obviously as wrinkles propagate. The formula of the bending stiffness is obtained based on the membrane theory in this paper. Furthermore, the definition of dimensionless bending stiffness factor is presented; the relationship of bending stiffness factor and wrinkling factor is derived; the bending stiffness factor is simplified as different linear functions with wrinkling factor, and the simplified model of bending stiffness of inflated beam under bending is also obtained. The bending stiffness including expression of wrinkling factor is substituted into the deflection differential equation, and then the slope and deflection equation of the inflated beam is deduced by integrating the deflection differential equation. Finally, the load-deflection curve is obtained, which is compared with the experimental data in a previous paper. It has a good agreement with each other.
文摘In the present study,actual three-dimensional structures are converted into a stick model of multi degree of-freedom(MDOF)systems for understanding the macro-behavior of structures.The study investigates the performance of three closely spaced,adjacent G+10,fixed-base MDOF systems with the mass aligned at the same levels and subjected to accidental underground blast loading.The acceleration time history of underground blast loading is generated based on past empirical relationships.The blast charge weight varies from 10 to 75 t while keeping the charge distance constant(R=100 m).The entire formulation is solved with the MATLAB solver,using the state space form solution.Three cases are considered,based on changing the position of the three stick systems.The first case considered left building rigid,middle building moderate rigid,and right building flexible.The second assumed left building flexible,middle building rigid,and right building moderate rigid.The third examined the left building as moderate rigid,the middle building as flexible,and the right building rigid.An analysis of the results shows that the arrangement with low stiffness,high stiffness,and moderately stiff buildings placed to the left,middle,and right side,respectively,yields minimum structural response when compared to the other two combinations.
基金supported by the Ministry of Science and Technology of China grants 2021YFA1101900(ND)National Natural Science Foundation of China grants(12422212,32071306,11902121)(JC)+1 种基金Huazhong University of Science and Technology Program for Academic Frontier Youth Team grant(2018QYTD01)(JC)the Fundamental Research Funds for the Central Universities(2024BRB004)(JC).
文摘The technology of induced pluripotent stem cells(iPSCs)has enabled the conversion of somatic cells into primitive undifferentiated cells via reprogramming.This approach provides possibilities for cell replacement therapies and drug screening,but the potential risk of tumorigenesis hampers its further development and in vivo application.How to generate differentiated cells such as valvular endothelial cells(VECs)has remained a major challenge.Utilizing a combinatorial strategy of selective soluble chemicals,cytokines and substrate stiffness modulation,mouse embryonic fibroblasts are directly and efficiently transdifferentiated into induced aortic endothelial cell-like cells(iAECs),or human primary adult fibroblasts are transdifferentiated into induced valvular endothelial cell-like cells(hiVECs),without expressing pluripotency stem cell markers.These iAECs and hiVECs express VEC-associated genes and proteins and VEC-specific marker NFATC1 and are functional in culture and on decellu-larized porcine aortic valves,like mouse aortic endothelial cells or human primary aortic valvular endothelial cells.The iAECs and hiVECs seeded on decellularized porcine aortic valves stay intact and express VEC-associated proteins for 60 days after grafting into abdominal aorta of immune-compromised rats.In contrast,induced pluripotent stem cells(iPSCs)are less efficient in differentiating into VEC-like cells and pluripotency marker Nanog is expressed in a small subpopulation of iPSC-derived VEC-like cells that generate teratomas in SCID mice whereas hiVECs derived from transdifferentiation do not generate teratomas in vivo.Our findings highlight an approach to efficiently convert fibroblasts into iAECs and hiVECs and seed them onto decellularized aortic valves for safely generating autologous tissue-engineered aortic valves without using viruses or first reprogramming the cells into pluripotent stem cells.
