Molecule hydrogen(H_(2)) has been used to suppress tumor growth. To employ the H_(2) therapy, it is necessary to use a proper agent for continuous generation of H_(2). As a biodegradable metal, magnesium(Mg) generates...Molecule hydrogen(H_(2)) has been used to suppress tumor growth. To employ the H_(2) therapy, it is necessary to use a proper agent for continuous generation of H_(2). As a biodegradable metal, magnesium(Mg) generates H_(2) in an aqueous environment, but the H_(2) release rate is still too low. Here, we design a Mg-Al-Ca(AX) alloy that degrades very rapidly due to the presence of a secondary phase Al_(2)Ca. Having a reduction potential much higher than Mg and any other Mg-based secondary phases, Al_(2)Ca accelerates the corrosion of the Mg matrix by a micro-galvanic process. Al_(2)Ca also enhances the strength and ductility of the AX alloy. AX alloy rods show better anti-tumor efficacy than pure Mg rods in vivo. Moreover, implanted AX alloy rods can be heated under an alternating magnetic field to suppress large-size tumors.This work suggests that the H_(2) therapy using highly degradable Mg alloys may provide an effective cancer treatment.展开更多
ZrB_(2)-SiBCN ceramics with ZrO_(2) additive are hot-pressed under a constant applied pressure.The densification behavior of the composites is studied in a view of creep deformation by means of the Bernard-Granger and...ZrB_(2)-SiBCN ceramics with ZrO_(2) additive are hot-pressed under a constant applied pressure.The densification behavior of the composites is studied in a view of creep deformation by means of the Bernard-Granger and Guizard model.With determination of the stress exponent(n)and the apparent activation energy(Q_(d)),the specific deformation mechanisms controlling densification are supposed.Within lower temperature ranges of 1300-1400℃,the operative mechanism is considered to be grain boundary sliding accommodated by atom diffusion of the polymer-derived SiBCN(n=1,Q_(d)=123±5 kJ/mol)and by viscous flow of the amorphous SiBCN(n=2,Qd=249±5 kJ/mol).At higher temperatures,the controlling mechanism transforms to lattice or intra-granular diffusion creep(n=3-5)due to gradual consumption of the amorphous phase.It is suggested that diffusion of oxygen ions inside ZrO_(2) into the amorphous SiBCN decreases the viscosity,modifies the fluidity,and contributes to the grain boundary mobility.展开更多
基金financially supported by Shanghai Rising-Star Program (20QA1405000)the National Natural Science Foundation of China (nos.U2032124 and 82204850)。
文摘Molecule hydrogen(H_(2)) has been used to suppress tumor growth. To employ the H_(2) therapy, it is necessary to use a proper agent for continuous generation of H_(2). As a biodegradable metal, magnesium(Mg) generates H_(2) in an aqueous environment, but the H_(2) release rate is still too low. Here, we design a Mg-Al-Ca(AX) alloy that degrades very rapidly due to the presence of a secondary phase Al_(2)Ca. Having a reduction potential much higher than Mg and any other Mg-based secondary phases, Al_(2)Ca accelerates the corrosion of the Mg matrix by a micro-galvanic process. Al_(2)Ca also enhances the strength and ductility of the AX alloy. AX alloy rods show better anti-tumor efficacy than pure Mg rods in vivo. Moreover, implanted AX alloy rods can be heated under an alternating magnetic field to suppress large-size tumors.This work suggests that the H_(2) therapy using highly degradable Mg alloys may provide an effective cancer treatment.
基金Financial support from the National Natural Science Foundation of China(Grant No.51272009)is sincerely acknowledged.
文摘ZrB_(2)-SiBCN ceramics with ZrO_(2) additive are hot-pressed under a constant applied pressure.The densification behavior of the composites is studied in a view of creep deformation by means of the Bernard-Granger and Guizard model.With determination of the stress exponent(n)and the apparent activation energy(Q_(d)),the specific deformation mechanisms controlling densification are supposed.Within lower temperature ranges of 1300-1400℃,the operative mechanism is considered to be grain boundary sliding accommodated by atom diffusion of the polymer-derived SiBCN(n=1,Q_(d)=123±5 kJ/mol)and by viscous flow of the amorphous SiBCN(n=2,Qd=249±5 kJ/mol).At higher temperatures,the controlling mechanism transforms to lattice or intra-granular diffusion creep(n=3-5)due to gradual consumption of the amorphous phase.It is suggested that diffusion of oxygen ions inside ZrO_(2) into the amorphous SiBCN decreases the viscosity,modifies the fluidity,and contributes to the grain boundary mobility.
