Permeable roads generally exhibit inferior mechanical properties and shorter service life than traditional dense-graded/impermeable roads.Furthermore,the incorporation of recycled aggregates in their construction may ...Permeable roads generally exhibit inferior mechanical properties and shorter service life than traditional dense-graded/impermeable roads.Furthermore,the incorporation of recycled aggregates in their construction may exacerbate these limitations.To address these issues,this study introduced a novel cement-stabilized permeable recycled aggregate material.A total of 162 beam specimens prepared with nine different levels of cement-aggregate ratio were tested to evaluate their permeability,bending load,and bending fatigue life.The experimental results indicate that increasing the content of recycled aggregates led to a reduction in both permeability and bending load.Additionally,the inclusion of recycled aggregates diminished the energy dissipation capacity of the specimens.These findings were used to establish a robust relationship between the initial damage in cement-stabilized permeable recycled aggregate material specimens and their fatigue life,and to propose a predictive model for their fatigue performance.Further,a method for assessing fatigue damage based on the evolution of fatigue-induced strain and energy dissipation was developed.The findings of this study provide valuable insights into the mechanical behavior and fatigue performance of cement-stabilized permeable recycled aggregate materials,offering guidance for the design of low-carbon-emission,permeable,and durable roadways incorporating recycled aggregates.展开更多
Polyamines(PAs) play diverse roles in plant growth and development,as well as responses to environmental stimuli.In this study,the effects of PAs on rice salt tolerance were investigated.Salt stress resulted in the al...Polyamines(PAs) play diverse roles in plant growth and development,as well as responses to environmental stimuli.In this study,the effects of PAs on rice salt tolerance were investigated.Salt stress resulted in the alteration of endogenous PAs levels in rice roots and leaves,where spermidine(Spd) and spermine(Spm) contents were increased,and putrescine(Put) content was decreased.RT-qPCR analysis revealed that PAs biosynthesis-related genes ADC1,ODC,and Arginase were significantly downregulated by salt treatment;however,SAMDC transcription was significantly upregulated.Exogenous Spm enhanced rice salt tolerance remarkably;however,exogenous Put and Spd undermined rice salt tolerance.Transgenic rice plants overexpressing SAMDC display a higher ratio of Spm/(Put+Spd) and enhanced salt tolerance.Salt stress also increased polyamine oxidase activities in rice,resulting in elevated reactive oxygen species(ROS) production.Our findings revealed that accumulation of Put and Spd substantially reduced salt tolerance in rice,likely by facilitating ROS production;whereas,conversion of Put and Spd to Spm contributes to rice salt tolerance.展开更多
基金Project(2024JJ2073)supported by the Science Fund for Distinguished Young Scholars of Hunan Province,ChinaProjects(2023YFC3807205,2019YFC1904704)+4 种基金supported by the National Key R&D Program of ChinaProject(52178443)supported by the National Natural Science Foundation of ChinaProject(2024ZZTS0109)supported by Fundamental Research Funds for the Central Universities of Central South University,China。
文摘Permeable roads generally exhibit inferior mechanical properties and shorter service life than traditional dense-graded/impermeable roads.Furthermore,the incorporation of recycled aggregates in their construction may exacerbate these limitations.To address these issues,this study introduced a novel cement-stabilized permeable recycled aggregate material.A total of 162 beam specimens prepared with nine different levels of cement-aggregate ratio were tested to evaluate their permeability,bending load,and bending fatigue life.The experimental results indicate that increasing the content of recycled aggregates led to a reduction in both permeability and bending load.Additionally,the inclusion of recycled aggregates diminished the energy dissipation capacity of the specimens.These findings were used to establish a robust relationship between the initial damage in cement-stabilized permeable recycled aggregate material specimens and their fatigue life,and to propose a predictive model for their fatigue performance.Further,a method for assessing fatigue damage based on the evolution of fatigue-induced strain and energy dissipation was developed.The findings of this study provide valuable insights into the mechanical behavior and fatigue performance of cement-stabilized permeable recycled aggregate materials,offering guidance for the design of low-carbon-emission,permeable,and durable roadways incorporating recycled aggregates.
基金supported by the National Key R&D Program(2017YFD0200900)the Natural Science Foundation of China(31570252 and 31601629)the Chinese Academy of Sciences(CAS)and the World Academy of Sciences(TWAS)Presidents Fellowship for supporting Md Azizul Islam as a doctoral student(2015CTF068)
文摘Polyamines(PAs) play diverse roles in plant growth and development,as well as responses to environmental stimuli.In this study,the effects of PAs on rice salt tolerance were investigated.Salt stress resulted in the alteration of endogenous PAs levels in rice roots and leaves,where spermidine(Spd) and spermine(Spm) contents were increased,and putrescine(Put) content was decreased.RT-qPCR analysis revealed that PAs biosynthesis-related genes ADC1,ODC,and Arginase were significantly downregulated by salt treatment;however,SAMDC transcription was significantly upregulated.Exogenous Spm enhanced rice salt tolerance remarkably;however,exogenous Put and Spd undermined rice salt tolerance.Transgenic rice plants overexpressing SAMDC display a higher ratio of Spm/(Put+Spd) and enhanced salt tolerance.Salt stress also increased polyamine oxidase activities in rice,resulting in elevated reactive oxygen species(ROS) production.Our findings revealed that accumulation of Put and Spd substantially reduced salt tolerance in rice,likely by facilitating ROS production;whereas,conversion of Put and Spd to Spm contributes to rice salt tolerance.
