Selective laser melting(SLM),as an additive manufacturing technology,has garnered widespread attention for its capability to fabricate components with complex geometries and to tailor the microstructure and mechanical...Selective laser melting(SLM),as an additive manufacturing technology,has garnered widespread attention for its capability to fabricate components with complex geometries and to tailor the microstructure and mechanical properties under specific conditions.However,the intrinsic influence mechanism of microstructure formation under non-equilibrium solidification conditions in SLM processes has not been clearly revealed.In the present work,the influence of Al concentration and process parameters on the microstructure forming mechanism of Al_(x)CoCrFeNi HEAs prepared by SLM is investigated by molecular dynamics simulation method.The simulation results show that the difference in Al content significantly affects the microstructure formation of HEAs,including the growth rate and morphology of columnar crystals,stress distribution at grain boundaries,and defect structure.In addition,the results show that increasing the substrate temperature improves the solidification formability,reduces microstructural defects,and helps reduce residual stress in Al_(x)CoCrFeNi HEAs.By analyzing the influence of heat and solute flow in the molten pool on the growth of columnar crystals,it is found that spatial fluctuations in Al concentration during the non-equilibrium solidification process inhibit the high cooling rates induced by steep temperature gradients.These findings promote the understanding of the forming mechanism of microstructure in HEAs prepared by SLM and provide theoretical guidance for designing high-performance SLM-fabricated HEAs.展开更多
Plants possess a hydrophobic layer of wax on their aerial surface,consisting mainly of amorphous intra-cuticular wax and epicuticular wax crystals(Kunst and Samuels,2003).This waxy coating contains a wide variety of v...Plants possess a hydrophobic layer of wax on their aerial surface,consisting mainly of amorphous intra-cuticular wax and epicuticular wax crystals(Kunst and Samuels,2003).This waxy coating contains a wide variety of very-long-chain fatty acids(VLCFAs)and their derivatives,including alkanes,alcohols,aldehydes,esters,and ketones.展开更多
Gradient structures(GS)play a crucial role in achieving a balance between strength and plasticity in metals and alloys.However,there is still a lack of understanding of the mechanisms that maintain a plasticity gradie...Gradient structures(GS)play a crucial role in achieving a balance between strength and plasticity in metals and alloys.However,there is still a lack of understanding of the mechanisms that maintain a plasticity gradient to prevent the premature failure of fine grains in GS materials.In this work,by incorporating experimental data and the Hall-Petch relationship,we develop a size-dependent crystal plasticity model to investigate the deformation mechanisms for enhancing the strength and plasticity in polycrystalline high entropy alloys.The simulations of the GS model align well with the experimental results,exhibiting strong strain and stress gradients to improve the mechanical properties.Under the conditions of significant de-formation incompatibility,the strain gradient predominantly drives the enhancement of plasticity mechanisms.As the de-formation incompatibility decreases,the stress gradient begins to play a significant role in comparison with the strain gradient.This shift is attributed to the regular variations in dislocation density within different domains.As the grain size gradients and loads decrease,the dislocation density becomes more uniform across the domains,hindering the formation of strong domain boundaries.While this may impede the activation of strain gradients,it facilitates the activation of stress gradients as a supplementary measure.By designing multilayered GS structures to alter the distribution of dislocation density,we can control the activation levels of stress and strain gradients,thereby influencing the plasticity mechanisms and mechanical properties of the material.展开更多
Soil organic carbon(SOC)plays a crucial role in mangrove blue carbon formation,yet the differences in microbemediated underlying SOC sequestration between introduced and native mangroves remain unclear.Here,we compare...Soil organic carbon(SOC)plays a crucial role in mangrove blue carbon formation,yet the differences in microbemediated underlying SOC sequestration between introduced and native mangroves remain unclear.Here,we compared the SOC pool,including recalcitrant organic carbon(ROC)and labile carbon pools,as well as three residual carbon sources(amino sugars,lignin phenols,and lipids)in sediments between mangroves of introduced Sonneratia apetala and native Kandelia obovata,and further connected them with microbial life strategies and C metabolism capability.The results showed that SOC accumulation in S.apetala(SA)sediment was about 30%-50% of that in K.obovata(KO)sediment.ROC was the dominant form of SOC in long-term sequestration(76%-83%),while lignin phenols,amino sugars,and lipids were important sources of ROC.In S.apetala sediments,the ROC content was positively correlated with amino sugars,resulting from the more r-strategist microbes that can rapidly convert plant-derived carbon into microbial biomass,which is subsequently transformed into microbial necromass.In contrast,in K.obovata sediments,ROC content showed a stronger positive correlation with the concentrations of lignin phenols and lipids.More K-strategist fungi in the topsoil of K.obovata increased enzyme activities,while more K-strategist bacteria in the subsoil enhanced carbon utilization capacity,thereby increasing lignin phenols and lipids from plant residues in both soil layers.Meanwhile,higher Ca^(2+)concentrations in K.obovata sediments protected three residual carbons from further microbe decomposition.This study provides valuable insights into the molecular mechanisms of SOC sequestration mediated by microbial life strategies in mangrove ecosystems.展开更多
Colorectal cancer(CRC)originates from biological events caused by gene mutations in normal intestinal epithelial cells(IECs).Sorting nexin 10(SNX10)is a tumor suppressor in CRC that is involved in regulating chaperone...Colorectal cancer(CRC)originates from biological events caused by gene mutations in normal intestinal epithelial cells(IECs).Sorting nexin 10(SNX10)is a tumor suppressor in CRC that is involved in regulating chaperone-mediated autophagy(CMA)activity,which is implicated in the pathogenesis of CRC and glycolysis process.DEP domain containing 5(DEPDC5)is a negative upstream regulator of mammalian target of rapamycin complex 1(mTORC1).a-hederin has anti-CRC effects.We previously found that SNX10 knockdown in normal human IECs promoted glycolysis and decreased DEPDC5 expression,which was reversed by a-hederin.However,the specific mechanism has not yet been elucidated.Here,we aimed to investigate the specific regulatory mechanism of SNX10 on DEPDC5 expression,and the action of a-hederin on this process.We demonstrated that the degradation of DEPDC5 protein was accelerated after SNX10 knockdown,causing the activation of the mTORC1 pathway,which relied on CMA activation and lysosomal function enhancement.SNX10 interacted with DEPDC5 and recruited it to lysosomes for degradation,and the glycolysis level mediated by mTORC1 was elevated.Additionally,these phenotypes in shSNX10 IECs were compromised by SNX10 rescue.Moreover,a-hederin bound to the SNX10 eDEPDC5 complex and impaired the interaction between SNX10 and DEPDC5,thereby inhibiting CMAmediated DEPDC5 degradation,impairing the aberrant activation of mTORC1 signaling,and eventually reversing the elevation of glycolysis caused by SNX10 knockdown.Overall,we are the first to demonstrate that SNX10-mediated DEPDC5 degradation is a novel strategy for malignant transformation of normal human IECs,with a-hederin regulated during this process.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12102133).
文摘Selective laser melting(SLM),as an additive manufacturing technology,has garnered widespread attention for its capability to fabricate components with complex geometries and to tailor the microstructure and mechanical properties under specific conditions.However,the intrinsic influence mechanism of microstructure formation under non-equilibrium solidification conditions in SLM processes has not been clearly revealed.In the present work,the influence of Al concentration and process parameters on the microstructure forming mechanism of Al_(x)CoCrFeNi HEAs prepared by SLM is investigated by molecular dynamics simulation method.The simulation results show that the difference in Al content significantly affects the microstructure formation of HEAs,including the growth rate and morphology of columnar crystals,stress distribution at grain boundaries,and defect structure.In addition,the results show that increasing the substrate temperature improves the solidification formability,reduces microstructural defects,and helps reduce residual stress in Al_(x)CoCrFeNi HEAs.By analyzing the influence of heat and solute flow in the molten pool on the growth of columnar crystals,it is found that spatial fluctuations in Al concentration during the non-equilibrium solidification process inhibit the high cooling rates induced by steep temperature gradients.These findings promote the understanding of the forming mechanism of microstructure in HEAs prepared by SLM and provide theoretical guidance for designing high-performance SLM-fabricated HEAs.
基金supported by grants from the National Natural Science Foundation of China(Grant No.31972405).
文摘Plants possess a hydrophobic layer of wax on their aerial surface,consisting mainly of amorphous intra-cuticular wax and epicuticular wax crystals(Kunst and Samuels,2003).This waxy coating contains a wide variety of very-long-chain fatty acids(VLCFAs)and their derivatives,including alkanes,alcohols,aldehydes,esters,and ketones.
基金supported by the National Natural Science Foundation of China(Grant Nos.12372069,12172123,and 12072109)the Natural Science Foundation of Hunan Province(Grant No.2022JJ20001)the Hunan Provincial Innovation Foundation for Postgraduate(Grant No.CX20220378).
文摘Gradient structures(GS)play a crucial role in achieving a balance between strength and plasticity in metals and alloys.However,there is still a lack of understanding of the mechanisms that maintain a plasticity gradient to prevent the premature failure of fine grains in GS materials.In this work,by incorporating experimental data and the Hall-Petch relationship,we develop a size-dependent crystal plasticity model to investigate the deformation mechanisms for enhancing the strength and plasticity in polycrystalline high entropy alloys.The simulations of the GS model align well with the experimental results,exhibiting strong strain and stress gradients to improve the mechanical properties.Under the conditions of significant de-formation incompatibility,the strain gradient predominantly drives the enhancement of plasticity mechanisms.As the de-formation incompatibility decreases,the stress gradient begins to play a significant role in comparison with the strain gradient.This shift is attributed to the regular variations in dislocation density within different domains.As the grain size gradients and loads decrease,the dislocation density becomes more uniform across the domains,hindering the formation of strong domain boundaries.While this may impede the activation of strain gradients,it facilitates the activation of stress gradients as a supplementary measure.By designing multilayered GS structures to alter the distribution of dislocation density,we can control the activation levels of stress and strain gradients,thereby influencing the plasticity mechanisms and mechanical properties of the material.
基金supported by grants from the National Natural Science Foundation of China(Nos.42076117 and 32160051)the Guangdong Basic and Applied Basic Research Foundation(Nos.2023A1515012772,2024A1515011721,and 2024A1515012249).
文摘Soil organic carbon(SOC)plays a crucial role in mangrove blue carbon formation,yet the differences in microbemediated underlying SOC sequestration between introduced and native mangroves remain unclear.Here,we compared the SOC pool,including recalcitrant organic carbon(ROC)and labile carbon pools,as well as three residual carbon sources(amino sugars,lignin phenols,and lipids)in sediments between mangroves of introduced Sonneratia apetala and native Kandelia obovata,and further connected them with microbial life strategies and C metabolism capability.The results showed that SOC accumulation in S.apetala(SA)sediment was about 30%-50% of that in K.obovata(KO)sediment.ROC was the dominant form of SOC in long-term sequestration(76%-83%),while lignin phenols,amino sugars,and lipids were important sources of ROC.In S.apetala sediments,the ROC content was positively correlated with amino sugars,resulting from the more r-strategist microbes that can rapidly convert plant-derived carbon into microbial biomass,which is subsequently transformed into microbial necromass.In contrast,in K.obovata sediments,ROC content showed a stronger positive correlation with the concentrations of lignin phenols and lipids.More K-strategist fungi in the topsoil of K.obovata increased enzyme activities,while more K-strategist bacteria in the subsoil enhanced carbon utilization capacity,thereby increasing lignin phenols and lipids from plant residues in both soil layers.Meanwhile,higher Ca^(2+)concentrations in K.obovata sediments protected three residual carbons from further microbe decomposition.This study provides valuable insights into the molecular mechanisms of SOC sequestration mediated by microbial life strategies in mangrove ecosystems.
基金supported by the National Natural Science Foundation of China(81973523).
文摘Colorectal cancer(CRC)originates from biological events caused by gene mutations in normal intestinal epithelial cells(IECs).Sorting nexin 10(SNX10)is a tumor suppressor in CRC that is involved in regulating chaperone-mediated autophagy(CMA)activity,which is implicated in the pathogenesis of CRC and glycolysis process.DEP domain containing 5(DEPDC5)is a negative upstream regulator of mammalian target of rapamycin complex 1(mTORC1).a-hederin has anti-CRC effects.We previously found that SNX10 knockdown in normal human IECs promoted glycolysis and decreased DEPDC5 expression,which was reversed by a-hederin.However,the specific mechanism has not yet been elucidated.Here,we aimed to investigate the specific regulatory mechanism of SNX10 on DEPDC5 expression,and the action of a-hederin on this process.We demonstrated that the degradation of DEPDC5 protein was accelerated after SNX10 knockdown,causing the activation of the mTORC1 pathway,which relied on CMA activation and lysosomal function enhancement.SNX10 interacted with DEPDC5 and recruited it to lysosomes for degradation,and the glycolysis level mediated by mTORC1 was elevated.Additionally,these phenotypes in shSNX10 IECs were compromised by SNX10 rescue.Moreover,a-hederin bound to the SNX10 eDEPDC5 complex and impaired the interaction between SNX10 and DEPDC5,thereby inhibiting CMAmediated DEPDC5 degradation,impairing the aberrant activation of mTORC1 signaling,and eventually reversing the elevation of glycolysis caused by SNX10 knockdown.Overall,we are the first to demonstrate that SNX10-mediated DEPDC5 degradation is a novel strategy for malignant transformation of normal human IECs,with a-hederin regulated during this process.
