Background:Allergic eosinophilic asthma(EA)and eosinophilic granulomatosis with polyangiitis(EGPA)share significant overlaps in both epidemiology and pathogenesis,suggesting a potential link between the two con-dition...Background:Allergic eosinophilic asthma(EA)and eosinophilic granulomatosis with polyangiitis(EGPA)share significant overlaps in both epidemiology and pathogenesis,suggesting a potential link between the two con-ditions.Despite these associations,the underlying molecular and cellular mechanisms driving their connection remain poorly understood.Methods:We retrieved GSE143303 of EA and GSE144302 of EGPA from the GEO database and conducted dif-ferential expression analysis as well as functional enrichment analysis to identify differentially expressed genes(DEGs)and potential pathogenic pathways.A protein-protein interaction(PPI)network was generated using the STRING database.Key hub genes were determined through cytoHubba.We added two publicly reported EA and EGPA-related transcriptome datasets,GSE117038 and GSE119136,for mutual verification.Subsequent valida-tion was performed via immune infiltration assessment utilizing CIBERSORT.Results:In total,267 DEGs were identified,in which HSP90AA1,HSPA8,CCND1,RPS20,CD74,RPL5,RPS6,RHOA,RPS3A and FLT3LG are the top 10 hub genes,while the antigen processing and presentation pathway and leukocyte cell-cell adhesion pathway were the potential influential pathways.Increased naïve B cells and M1 type of Macrophages were detected in EA patients through immune infiltration analysis.Conclusions:Utilizing bioinformatics techniques,this study is the initial investigation to uncover the shared mechanisms involving the antigen processing and presentation pathway and leukocyte adhesion pathways in the progression of both EA and EGPA.It may offer potential biomarkers for future studies on the underlying path-ogenesis and treatment of EA and EGPA as well as eosinophilia related co-morbidities.展开更多
Mg-Gd-Zn based alloys have better creep resistance than other Mg alloys and attract more attention at elevated temperatures.However,the multiple alloying elements and various heat treatment conditions,combined with co...Mg-Gd-Zn based alloys have better creep resistance than other Mg alloys and attract more attention at elevated temperatures.However,the multiple alloying elements and various heat treatment conditions,combined with complex microstructural evolution during creep tests,bring great challenges in understanding and predicting creep behaviors.In this study,we proposed to predict the creep properties and reveal the creep mechanisms of Mg-Gd-Zn based alloys by machine learning.On the one hand,the minimum creep rates were effectively predicted by using a support vector regression model.The complex and nonmonotonic effects of test temperature,test stress,alloying elements,and heat treatment conditions on the creep properties were revealed.On the other hand,the creep stress exponents and creep activation energies were calculated by machine learning to analyze the variation of creep mechanisms,based on which the constitutive equations of Mg-Gd-Zn based alloys were obtained.This study introduces an efficient method to comprehend creep behaviors through machine learning,offering valuable insights for the future design and selection of Mg alloys.展开更多
Heterostructures of alloyed composites,comprising heterogeneous domains with dramatically different constitutive properties,hold remarkable potential to expand the realm of material design systems and resolve the trad...Heterostructures of alloyed composites,comprising heterogeneous domains with dramatically different constitutive properties,hold remarkable potential to expand the realm of material design systems and resolve the tradeoffbetween strength and ductility.This study introduces an innovative materials design method for synthesizing gradient pseudo-precipitates heterostructure(GPHS)in non-heat-treatable Al-2.5%Mg alloys.Utilizing cost-effective mild steel as both the diffusion source and protective layer,this heterostructure is achieved through pin-less friction stir-assisted cyclic localized deformation process.Exogenous Fe atoms diffuse across the interface by friction stir-induced heat conduction,forming Fe-Al second-phase particles in the Al alloy matrix.A rapid inter-diffusion mechanism is activated in conjunction with dense dislocation walls,grain boundaries,and sub-structures,resulting in the formation of pseudo-precipitates.These pseudo-precipitates are ultimately dispersed in a gradient distribution throughout the entire thickness of the Al alloy matrix induced by localized incremental deformation.The GPHSed Al-2.5%Mg alloy exhibits an enhanced synergy of strength and ductility,with a uniform elongation increase from 11%to 21.2%,while maintaining the strength.Multiple strengthening and hardening mechanisms,such as solid solution strengthening,dislocation hardening,and second phase strengthening,work synergistically to promote mechanical performance.Notably,the hetero-deformation between hard pseudo-precipitates and soft Al alloy matrix induces additional strain hardening,leading to high ductility.This work provides a fresh perspective on the design and fabrication of high-performance alloys with advanced heterostructures,especially for non-heat-treatable alloys.展开更多
In traditional physical metallurgy,once recrystallization occurs,it will proceed to 100%along with time even at relatively low temperatures,resulting in the limited thermal stability of partially recrystallized alloys...In traditional physical metallurgy,once recrystallization occurs,it will proceed to 100%along with time even at relatively low temperatures,resulting in the limited thermal stability of partially recrystallized alloys.Here,we proposed the strategy of achieving the endless recrystallization state at high temperature(~0.6T_(m))in high entropy alloys for the first time.The partially recrystallized microstructures remained stable after annealing at 700℃ for 1440 h toward endless recrystallization with kinetics analysis.Benefiting from the ultra-thermostable heterostructures,the alloy exhibited excellent mechanical properties of~1.6 GPa tensile strength at room temperature and~1.1 GPa tensile strength at 600°C even after exposure at 700℃ for 720 h.The kinetics of recovery,recrystallization,grain growth,and precipitate coarsening were quantitatively analyzed to uncover the mechanisms of endless recrystallization.The results revealed that the stable state of 50%recrystallization at 700℃ can be attributed to the precipitates inhibited recrystallization and the continued recovery decreased stored energy in the non-recrystallized regions.Furthermore,the grain size was stable in the recrystallized regions due to the strong pinning effect of the intergranular precipitates with slow coarsening rates.These findings created a brand-new state of endless recrystallization with the combination of recovery and recrystallization,which can significantly broaden the service temperature range of heterogeneous materials.展开更多
With important application prospects, eutectic high entropy alloys have received extensive attention for their excellent strength and ductility in a large temperature range. The excellent casting characteristics of eu...With important application prospects, eutectic high entropy alloys have received extensive attention for their excellent strength and ductility in a large temperature range. The excellent casting characteristics of eutectic high entropy alloys make it possible to achieve well manufacturability of selective laser melting.For the first time, we have achieved crack-free eutectic high entropy alloy fabricated by selective laser melting, which has excellent mechanical properties in a wide temperature range from -196 ℃ to 760 ℃ due to ultra-fine eutectic lamellar spacing of 150–200 nm and lamellar colony of 2–6 μm. Specifically,the room temperature tensile strength exceeds 1400 MPa and the elongation is more than 20%, which significantly improved compared with those manufactured by other techniques with lower cooling rate.展开更多
Eutectic high-entropy alloys(EHEAs)that have superior formability are attractive for direct laser deposition technology.In this study,a regular-shaped bulk Ni_(32)Co_(30)Cr_(10)Fe_(10)Al_(18)EHEA without apparent pore...Eutectic high-entropy alloys(EHEAs)that have superior formability are attractive for direct laser deposition technology.In this study,a regular-shaped bulk Ni_(32)Co_(30)Cr_(10)Fe_(10)Al_(18)EHEA without apparent pores and micro-cracks was successfully fabricated by direct laser deposition.The as-deposited alloy showed a high tensile strength of 1.3 GPa with a ductility of 35%at ambient temperature and a tensile strength of 320 MPa at 760℃.The deformation mechanisms of the as-deposited alloy at ambient and elevated temperatures were investigated by coupling the in-situ tensile test with a scanning electron microscope.It is revealed that the excellent combination of strength and ductility originated from the synergic effects of the FCC and B2 phases in eutectic lamellae.And the generation of cracks along phase boundaries restricted its high-temperature strength above 760℃.展开更多
High-entropy alloys have attracted broad research interests due to their unique and intriguing mechanical properties. As a category of high-entropy alloys, eutectic high-entropy alloys combine the advantages of eutect...High-entropy alloys have attracted broad research interests due to their unique and intriguing mechanical properties. As a category of high-entropy alloys, eutectic high-entropy alloys combine the advantages of eutectic and high-entropy alloys, with excellent mechanical properties and casting properties. Some eutectic high-entropy alloys have been developed and shown exciting properties. In this paper, based on the physical metallurgy of eutectic high-entropy alloy, medium-entropy alloy Fe_(2)NiCrNb_(x) was designed. The as-cast alloy is composed of FCC and Laves phases, Nb element promotes the formation of primary Laves phase, and the hardness of the alloy increases with the increase in Nb element. Among the four alloys, the eutectic chemical composition at eutectic point is Fe_(2)NiCrNb_(0.34);the alloy has a good strength and plastic balance. The ultimate comprehensive strength is 2267 MPa, and the fracture strain is 30.8%. The experiment data and analyses identified the eutectic points and the excellent mechanical behavior. Moreover, the expensive Co element was replaced by Fe element. This cheap medium-entropy alloy has promising prospect in the consideration of the cost performance ratio.展开更多
A defect-free Ti_(2)AlNb joint has been obtained by the inertia friction welding(IFW)technology.The weld zone(WZ)is composed of B2 grains refined by discontinuous dynamic recrystallization and enhanced by grain refine...A defect-free Ti_(2)AlNb joint has been obtained by the inertia friction welding(IFW)technology.The weld zone(WZ)is composed of B2 grains refined by discontinuous dynamic recrystallization and enhanced by grain refinement strengthening.And the average microhardness decreases by about 30 HV from the WZ to the base metal.In-situ SEM analysis reveals that the heterogeneous structure of the joint causes strong strain partitioning during tensile deformation.The microcrack initiation occurs at the interface of the initial B2 phases and B2/O boundaries.Owing to stress concentration,the multi-slip bands and cracks tend to generate in the heat-affected zone(HAZ),causing a premature fracture.展开更多
15Cr ferrite steels are urgently required in advanced Ultra-supercritical power plants but meet design challenges in balancing excellent strength and plasticity at high temperatures.We developed a three-step learning ...15Cr ferrite steels are urgently required in advanced Ultra-supercritical power plants but meet design challenges in balancing excellent strength and plasticity at high temperatures.We developed a three-step learning strategy based on mutually driven machine learning and purposeful experiments to complete this multi-objective task.Compared with traditional adaptive learning and local-interpolation learning,this step-by-step modular manner provides good transparency and interpretability of the information flow,which is ensured by identifying essential factors from an exquisitely prepared composition-microstructure dataset,and learning valuable knowledge about the composition-property relationship.The requirement of only two groups of experiments indicates the low cost and high efficiency of the strategy.Performing the strategy,we found that Ti is another key element affecting the Laves phase besides Mo and W,and their effects on ultimate tensile strength(UTS)and elongation were also uncovered.Importantly,several low-cost steels free of Co were successfully designed,and the best steel exhibited 156%,31%,and 62%higher UTS and elongation at 650°C than the typical 9Cr,15Cr,and 20Cr steels,respectively.Based on the advantages and success of the strategy in terms of alloy improvement,we believe the strategy suits other multi-objective design tasks in more materials systems.展开更多
Background:B-cell receptor-associated protein 31(BCAP31)has protective effects against alveolar epithelial type lIl cells(AECll)damage by inhibiting mitochondrial injury in acute lung injury(ALI)induced by lipopolysac...Background:B-cell receptor-associated protein 31(BCAP31)has protective effects against alveolar epithelial type lIl cells(AECll)damage by inhibiting mitochondrial injury in acute lung injury(ALI)induced by lipopolysaccharide(LPS),whereas the precise mechanism is still unclear.It is known that PTEN-induced putative kinase 1(PINK1)/Parkin-mediated mitophagy can remove damaged mitochondria selectively,which may be involved in BCAP31 protection against mitochondrial injury.Methods:In the current study,ALI mice models were established by using surfactant protein C(Sftpc)-BCAP31 transgenic mice(BCAP31^(TG) mice)and AECIl-specific BCAP31 knockout mice(BCAP31^(CKO) mice)treated with LPS.Results:BCAP31 expression in lung tissue and AECll were inhibited in ALI mice.Under LPS challenge,lower level of BCAP31 was found to correlate positively with pathological injury of the lung,respiratory dysfunction,mortality rates,inflammation response,and AECll damage.Further study showed that down-regulation of BCAP31 induced decreased phosphorylation of PINK1 via reduced binding to PINK1,thereby restraining PINK1/Parkin-mediated mitophagy.Down-regulation of mitophagy promoted mitochondrial injury,as shown by the increase in mitochondrial permeability transition pore opening rate,together with enhanced mitochondrial reactive oxygen species(mROS),which were accompanied by increased cellular apoptosis and reactive oxygen species(ROS).The increased cellular ROS contributed to the inflammatory response via activation of nuclear factor kB(NF-kB).In contrast,BCAP31 overexpression promoted phosphorylation of PINK1 and PINK1/Parkin-mediated mitophagy,thus blocking the mROS/ROS/NF-kB pathway,favoring a protective condition that ultimately led to the inhibition of AECl apoptosis and inflammatory response in LPS-induced ALI.Conclusion:Ultimately,BCAP31 alleviated ALI by activating PINK1/Parkin-mediated mitophagy and blocking the mROS/ROS/NF-kB pathway in AECll.展开更多
Background:Ebstein’s anomaly(EA)is a rare and complex congenital heart anomaly,and the effect of surgical treatment is not ideal.This study aims to introduce our experience in management strategies,surgical technique...Background:Ebstein’s anomaly(EA)is a rare and complex congenital heart anomaly,and the effect of surgical treatment is not ideal.This study aims to introduce our experience in management strategies,surgical techniques,and operative indications for patients with Ebstein’s anomaly.Methods:A retrospective study of 258 operations was performed in 253 patients by the same cardiac surgeon in The First Hospital of Tsinghua University between March 2004 and January 2020.32 patients had previously received cardiac surgery in other hospitals.The clinical data including diagnosis,operative indications,techniques,pathological changes,and survival rates were collected and analyzed.Results:Anatomical correction was performed in 203(78.7%)operations,1½ventricle repair in 38(14.7%)operations,tricuspid valve repair only in four operations(1.6%),tricuspid valve replacement in ten(3.9%),total cavopulmonary connection(TCPC)in two(0.8%),and Glenn operation in one operation(0.4%).Reoperation was performed in five patients(2.0%)during hospitalization.Among them,tricuspid valve replacement was performed in one patient,1½ventricle repair in two patients,and tricuspid valve annulus reinforcement in two patients.Five patients died with an early mortality rate of 2.0%.Complete atrioventricular conduction block was complicated in one patient(0.4%).A total of 244 patients was followed up(four in the 253 patients lost)with a duration of 3.0-168.0(87.6±38.4)months.Cardiac function of 244 patients improved significantly with mean New York Heart Association(NYHA)functional class recovery from 3.5 to 1.1.The mean grade of tricuspid valve regurgitation improved from 3.6 to 1.5.Three late deaths(1.2%)occurred.The survival rates at five and ten years after surgery were 98.6%and 98.2%,respectively.Reoperation was performed in five patients(2.0%)during the follow-up period.Conclusion:Based on our management strategies and operative principles and techniques,anatomical correction of EA is capable of achieving excellent long-term results,and low rates of TCPC,1½ventricle repair and valvular replacement.展开更多
Cough is a vital defensive reflex for expelling harmful substances from the airway.The sensory afferents for the cough reflex have been intensively studied.However,the brain mechanisms underlying the cough reflex rema...Cough is a vital defensive reflex for expelling harmful substances from the airway.The sensory afferents for the cough reflex have been intensively studied.However,the brain mechanisms underlying the cough reflex remain poorly understood.Here,we developed a paradigm to quantitatively measure cough-like reflexes in mice.Using this paradigm,we found that prodynorphin-expressing(Pdyn+)neurons in the nucleus of the solitary tract(NTS)are critical for capsaicin-induced cough-like reflexes.These neurons receive cough-related neural signals from Trpv1+vagal sensory neurons.The activation of Pdyn+NTS neurons triggered respiratory responses resembling cough-like reflexes.Among the divergent projections of Pdyn+NTS neurons,a glutamatergic pathway projecting to the caudal ventral respiratory group(cVRG),the canonical cough center,was necessary and sufficient for capsaicin-induced cough-like reflexes.These results reveal that Pdyn+NTS neurons,as a key neuronal population at the entry point of the vagus nerve to the brainstem,initiate cough-like reflexes in mice.展开更多
Circadian rhythm is a self-sustaining endogenous oscillation that serves as an internal timekeeping mechanism adapted to the Earth’s 24-h rotational schedule.It exists ubiquitously in nearly all organisms,from prokar...Circadian rhythm is a self-sustaining endogenous oscillation that serves as an internal timekeeping mechanism adapted to the Earth’s 24-h rotational schedule.It exists ubiquitously in nearly all organisms,from prokaryotes to mammals,and regulates diverse physiological and behavioral processes by synchronizing them with environmental fluctuations[1].Previous reports indicated that circadian rhythms exist in biological individuals and cells cultured in vitro[2].The mammalian circadian rhythm system consists of a central pacemaker located in the suprachiasmatic nucleus(SCN)of the hypothalamus,which coordinates peripheral rhythms through the sympathetic and parasympathetic nervous systems[3].This hierarchical mechanism uses neural populations as optimal models for circadian rhythm research.展开更多
基金funded by National Natural Science Foundation of China(NO.82370083).
文摘Background:Allergic eosinophilic asthma(EA)and eosinophilic granulomatosis with polyangiitis(EGPA)share significant overlaps in both epidemiology and pathogenesis,suggesting a potential link between the two con-ditions.Despite these associations,the underlying molecular and cellular mechanisms driving their connection remain poorly understood.Methods:We retrieved GSE143303 of EA and GSE144302 of EGPA from the GEO database and conducted dif-ferential expression analysis as well as functional enrichment analysis to identify differentially expressed genes(DEGs)and potential pathogenic pathways.A protein-protein interaction(PPI)network was generated using the STRING database.Key hub genes were determined through cytoHubba.We added two publicly reported EA and EGPA-related transcriptome datasets,GSE117038 and GSE119136,for mutual verification.Subsequent valida-tion was performed via immune infiltration assessment utilizing CIBERSORT.Results:In total,267 DEGs were identified,in which HSP90AA1,HSPA8,CCND1,RPS20,CD74,RPL5,RPS6,RHOA,RPS3A and FLT3LG are the top 10 hub genes,while the antigen processing and presentation pathway and leukocyte cell-cell adhesion pathway were the potential influential pathways.Increased naïve B cells and M1 type of Macrophages were detected in EA patients through immune infiltration analysis.Conclusions:Utilizing bioinformatics techniques,this study is the initial investigation to uncover the shared mechanisms involving the antigen processing and presentation pathway and leukocyte adhesion pathways in the progression of both EA and EGPA.It may offer potential biomarkers for future studies on the underlying path-ogenesis and treatment of EA and EGPA as well as eosinophilia related co-morbidities.
基金supported by the National Science and Technology Major Project(Grant number J2019-VI-0004-0118)the National Natural Science Foundation of China(Grant number 51771152)+2 种基金the National Key R&D Program of China(Grant number 2018YFB1106800)supported by the Brain Pool Program through the National Research Foundation of Korea(NRF)(Grant No.RS-2023-00304296)supported by the Brain Pool Program through National Research Foundation of Korea(NRF)(Grant No.RS-2023-00222130).
文摘Mg-Gd-Zn based alloys have better creep resistance than other Mg alloys and attract more attention at elevated temperatures.However,the multiple alloying elements and various heat treatment conditions,combined with complex microstructural evolution during creep tests,bring great challenges in understanding and predicting creep behaviors.In this study,we proposed to predict the creep properties and reveal the creep mechanisms of Mg-Gd-Zn based alloys by machine learning.On the one hand,the minimum creep rates were effectively predicted by using a support vector regression model.The complex and nonmonotonic effects of test temperature,test stress,alloying elements,and heat treatment conditions on the creep properties were revealed.On the other hand,the creep stress exponents and creep activation energies were calculated by machine learning to analyze the variation of creep mechanisms,based on which the constitutive equations of Mg-Gd-Zn based alloys were obtained.This study introduces an efficient method to comprehend creep behaviors through machine learning,offering valuable insights for the future design and selection of Mg alloys.
基金financial support from the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIP)(Nos.NRF-2021R1A2C3006662 and NRF-2022R1A5A1030054)supported by Brain Pool Program through the National Research Foundation of Korea(NRF-RS202300263999).
文摘Heterostructures of alloyed composites,comprising heterogeneous domains with dramatically different constitutive properties,hold remarkable potential to expand the realm of material design systems and resolve the tradeoffbetween strength and ductility.This study introduces an innovative materials design method for synthesizing gradient pseudo-precipitates heterostructure(GPHS)in non-heat-treatable Al-2.5%Mg alloys.Utilizing cost-effective mild steel as both the diffusion source and protective layer,this heterostructure is achieved through pin-less friction stir-assisted cyclic localized deformation process.Exogenous Fe atoms diffuse across the interface by friction stir-induced heat conduction,forming Fe-Al second-phase particles in the Al alloy matrix.A rapid inter-diffusion mechanism is activated in conjunction with dense dislocation walls,grain boundaries,and sub-structures,resulting in the formation of pseudo-precipitates.These pseudo-precipitates are ultimately dispersed in a gradient distribution throughout the entire thickness of the Al alloy matrix induced by localized incremental deformation.The GPHSed Al-2.5%Mg alloy exhibits an enhanced synergy of strength and ductility,with a uniform elongation increase from 11%to 21.2%,while maintaining the strength.Multiple strengthening and hardening mechanisms,such as solid solution strengthening,dislocation hardening,and second phase strengthening,work synergistically to promote mechanical performance.Notably,the hetero-deformation between hard pseudo-precipitates and soft Al alloy matrix induces additional strain hardening,leading to high ductility.This work provides a fresh perspective on the design and fabrication of high-performance alloys with advanced heterostructures,especially for non-heat-treatable alloys.
基金supported by the National Natural Science Foundation of China(Nos.51771149 and 51871183)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(Grant No.CX202022)。
文摘In traditional physical metallurgy,once recrystallization occurs,it will proceed to 100%along with time even at relatively low temperatures,resulting in the limited thermal stability of partially recrystallized alloys.Here,we proposed the strategy of achieving the endless recrystallization state at high temperature(~0.6T_(m))in high entropy alloys for the first time.The partially recrystallized microstructures remained stable after annealing at 700℃ for 1440 h toward endless recrystallization with kinetics analysis.Benefiting from the ultra-thermostable heterostructures,the alloy exhibited excellent mechanical properties of~1.6 GPa tensile strength at room temperature and~1.1 GPa tensile strength at 600°C even after exposure at 700℃ for 720 h.The kinetics of recovery,recrystallization,grain growth,and precipitate coarsening were quantitatively analyzed to uncover the mechanisms of endless recrystallization.The results revealed that the stable state of 50%recrystallization at 700℃ can be attributed to the precipitates inhibited recrystallization and the continued recovery decreased stored energy in the non-recrystallized regions.Furthermore,the grain size was stable in the recrystallized regions due to the strong pinning effect of the intergranular precipitates with slow coarsening rates.These findings created a brand-new state of endless recrystallization with the combination of recovery and recrystallization,which can significantly broaden the service temperature range of heterogeneous materials.
基金supported by the National Key R&D Program of China (No.2018YFC0310400)the Research Fund of the State Key Laboratory of Solidification Processing,China (No.2020TS-06,2021-TS-02)。
文摘With important application prospects, eutectic high entropy alloys have received extensive attention for their excellent strength and ductility in a large temperature range. The excellent casting characteristics of eutectic high entropy alloys make it possible to achieve well manufacturability of selective laser melting.For the first time, we have achieved crack-free eutectic high entropy alloy fabricated by selective laser melting, which has excellent mechanical properties in a wide temperature range from -196 ℃ to 760 ℃ due to ultra-fine eutectic lamellar spacing of 150–200 nm and lamellar colony of 2–6 μm. Specifically,the room temperature tensile strength exceeds 1400 MPa and the elongation is more than 20%, which significantly improved compared with those manufactured by other techniques with lower cooling rate.
基金financially supported by the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(Grant Nos.2020-TS-06,2021-TS-02).
文摘Eutectic high-entropy alloys(EHEAs)that have superior formability are attractive for direct laser deposition technology.In this study,a regular-shaped bulk Ni_(32)Co_(30)Cr_(10)Fe_(10)Al_(18)EHEA without apparent pores and micro-cracks was successfully fabricated by direct laser deposition.The as-deposited alloy showed a high tensile strength of 1.3 GPa with a ductility of 35%at ambient temperature and a tensile strength of 320 MPa at 760℃.The deformation mechanisms of the as-deposited alloy at ambient and elevated temperatures were investigated by coupling the in-situ tensile test with a scanning electron microscope.It is revealed that the excellent combination of strength and ductility originated from the synergic effects of the FCC and B2 phases in eutectic lamellae.And the generation of cracks along phase boundaries restricted its high-temperature strength above 760℃.
基金financially supported by the National Key R&D Program of China(Grant No.2018YFB1105804)the Research Fund of the State Key Laboratory of Solidifi cation Processing(NPU),China(Grant No.2020-TS-06)the BIAM YiCai Youth Foundation Program(Grant No.KJ53200134)。
文摘High-entropy alloys have attracted broad research interests due to their unique and intriguing mechanical properties. As a category of high-entropy alloys, eutectic high-entropy alloys combine the advantages of eutectic and high-entropy alloys, with excellent mechanical properties and casting properties. Some eutectic high-entropy alloys have been developed and shown exciting properties. In this paper, based on the physical metallurgy of eutectic high-entropy alloy, medium-entropy alloy Fe_(2)NiCrNb_(x) was designed. The as-cast alloy is composed of FCC and Laves phases, Nb element promotes the formation of primary Laves phase, and the hardness of the alloy increases with the increase in Nb element. Among the four alloys, the eutectic chemical composition at eutectic point is Fe_(2)NiCrNb_(0.34);the alloy has a good strength and plastic balance. The ultimate comprehensive strength is 2267 MPa, and the fracture strain is 30.8%. The experiment data and analyses identified the eutectic points and the excellent mechanical behavior. Moreover, the expensive Co element was replaced by Fe element. This cheap medium-entropy alloy has promising prospect in the consideration of the cost performance ratio.
基金financially supported by the National Natural Science Foundation of China(No.51871183).
文摘A defect-free Ti_(2)AlNb joint has been obtained by the inertia friction welding(IFW)technology.The weld zone(WZ)is composed of B2 grains refined by discontinuous dynamic recrystallization and enhanced by grain refinement strengthening.And the average microhardness decreases by about 30 HV from the WZ to the base metal.In-situ SEM analysis reveals that the heterogeneous structure of the joint causes strong strain partitioning during tensile deformation.The microcrack initiation occurs at the interface of the initial B2 phases and B2/O boundaries.Owing to stress concentration,the multi-slip bands and cracks tend to generate in the heat-affected zone(HAZ),causing a premature fracture.
基金supported by the National Natural Science Foundation of China(Grant Nos.51871183 and 51874245)the Research Fund of the State Key Laboratory of Solidification Processing(NPU)China(Grant No.2020-TS-06)。
文摘15Cr ferrite steels are urgently required in advanced Ultra-supercritical power plants but meet design challenges in balancing excellent strength and plasticity at high temperatures.We developed a three-step learning strategy based on mutually driven machine learning and purposeful experiments to complete this multi-objective task.Compared with traditional adaptive learning and local-interpolation learning,this step-by-step modular manner provides good transparency and interpretability of the information flow,which is ensured by identifying essential factors from an exquisitely prepared composition-microstructure dataset,and learning valuable knowledge about the composition-property relationship.The requirement of only two groups of experiments indicates the low cost and high efficiency of the strategy.Performing the strategy,we found that Ti is another key element affecting the Laves phase besides Mo and W,and their effects on ultimate tensile strength(UTS)and elongation were also uncovered.Importantly,several low-cost steels free of Co were successfully designed,and the best steel exhibited 156%,31%,and 62%higher UTS and elongation at 650°C than the typical 9Cr,15Cr,and 20Cr steels,respectively.Based on the advantages and success of the strategy in terms of alloy improvement,we believe the strategy suits other multi-objective design tasks in more materials systems.
基金supported by grants from the National Natural Science Foundation of China(No.82200091,No.82341089,and No.82370083)the Beijing Natural Science Foundation(No.7232150,No.7242029,No.7242028,and No.7222166)Chinese PLA General Hospital Youth Independent Innovation Science Fund Project(No.22QNFC086).
文摘Background:B-cell receptor-associated protein 31(BCAP31)has protective effects against alveolar epithelial type lIl cells(AECll)damage by inhibiting mitochondrial injury in acute lung injury(ALI)induced by lipopolysaccharide(LPS),whereas the precise mechanism is still unclear.It is known that PTEN-induced putative kinase 1(PINK1)/Parkin-mediated mitophagy can remove damaged mitochondria selectively,which may be involved in BCAP31 protection against mitochondrial injury.Methods:In the current study,ALI mice models were established by using surfactant protein C(Sftpc)-BCAP31 transgenic mice(BCAP31^(TG) mice)and AECIl-specific BCAP31 knockout mice(BCAP31^(CKO) mice)treated with LPS.Results:BCAP31 expression in lung tissue and AECll were inhibited in ALI mice.Under LPS challenge,lower level of BCAP31 was found to correlate positively with pathological injury of the lung,respiratory dysfunction,mortality rates,inflammation response,and AECll damage.Further study showed that down-regulation of BCAP31 induced decreased phosphorylation of PINK1 via reduced binding to PINK1,thereby restraining PINK1/Parkin-mediated mitophagy.Down-regulation of mitophagy promoted mitochondrial injury,as shown by the increase in mitochondrial permeability transition pore opening rate,together with enhanced mitochondrial reactive oxygen species(mROS),which were accompanied by increased cellular apoptosis and reactive oxygen species(ROS).The increased cellular ROS contributed to the inflammatory response via activation of nuclear factor kB(NF-kB).In contrast,BCAP31 overexpression promoted phosphorylation of PINK1 and PINK1/Parkin-mediated mitophagy,thus blocking the mROS/ROS/NF-kB pathway,favoring a protective condition that ultimately led to the inhibition of AECl apoptosis and inflammatory response in LPS-induced ALI.Conclusion:Ultimately,BCAP31 alleviated ALI by activating PINK1/Parkin-mediated mitophagy and blocking the mROS/ROS/NF-kB pathway in AECll.
文摘Background:Ebstein’s anomaly(EA)is a rare and complex congenital heart anomaly,and the effect of surgical treatment is not ideal.This study aims to introduce our experience in management strategies,surgical techniques,and operative indications for patients with Ebstein’s anomaly.Methods:A retrospective study of 258 operations was performed in 253 patients by the same cardiac surgeon in The First Hospital of Tsinghua University between March 2004 and January 2020.32 patients had previously received cardiac surgery in other hospitals.The clinical data including diagnosis,operative indications,techniques,pathological changes,and survival rates were collected and analyzed.Results:Anatomical correction was performed in 203(78.7%)operations,1½ventricle repair in 38(14.7%)operations,tricuspid valve repair only in four operations(1.6%),tricuspid valve replacement in ten(3.9%),total cavopulmonary connection(TCPC)in two(0.8%),and Glenn operation in one operation(0.4%).Reoperation was performed in five patients(2.0%)during hospitalization.Among them,tricuspid valve replacement was performed in one patient,1½ventricle repair in two patients,and tricuspid valve annulus reinforcement in two patients.Five patients died with an early mortality rate of 2.0%.Complete atrioventricular conduction block was complicated in one patient(0.4%).A total of 244 patients was followed up(four in the 253 patients lost)with a duration of 3.0-168.0(87.6±38.4)months.Cardiac function of 244 patients improved significantly with mean New York Heart Association(NYHA)functional class recovery from 3.5 to 1.1.The mean grade of tricuspid valve regurgitation improved from 3.6 to 1.5.Three late deaths(1.2%)occurred.The survival rates at five and ten years after surgery were 98.6%and 98.2%,respectively.Reoperation was performed in five patients(2.0%)during the follow-up period.Conclusion:Based on our management strategies and operative principles and techniques,anatomical correction of EA is capable of achieving excellent long-term results,and low rates of TCPC,1½ventricle repair and valvular replacement.
基金supported by the National Natural Science Foundation of China(31925019 to P.C.)the STI 2030 Major Projects(2021ZD0202701to P.C.)the New Cornerstone Science Foundation through the XPLORER PRIZE(to P.C.).All data are archived in NIBS.
文摘Cough is a vital defensive reflex for expelling harmful substances from the airway.The sensory afferents for the cough reflex have been intensively studied.However,the brain mechanisms underlying the cough reflex remain poorly understood.Here,we developed a paradigm to quantitatively measure cough-like reflexes in mice.Using this paradigm,we found that prodynorphin-expressing(Pdyn+)neurons in the nucleus of the solitary tract(NTS)are critical for capsaicin-induced cough-like reflexes.These neurons receive cough-related neural signals from Trpv1+vagal sensory neurons.The activation of Pdyn+NTS neurons triggered respiratory responses resembling cough-like reflexes.Among the divergent projections of Pdyn+NTS neurons,a glutamatergic pathway projecting to the caudal ventral respiratory group(cVRG),the canonical cough center,was necessary and sufficient for capsaicin-induced cough-like reflexes.These results reveal that Pdyn+NTS neurons,as a key neuronal population at the entry point of the vagus nerve to the brainstem,initiate cough-like reflexes in mice.
基金funded by the National Natural Science Foundation of China(no.12275329,Nan Ding,and no.12175289,Jufang Wang)the West Light Foundation of The Chinese Academy of Sciences(xbzglzb2022003,Nan Ding)+2 种基金the Science and Technology Research Project of Gansu Province(no.145RTSA012,Jufang Wang,and no.21JR7RA108,Nan Ding)the Gansu Provincial Science Fund for Distinguished Young Scholars(no.22JR5RA942,Wei Wang)the CuiYing Science and Technology Innovation Program of the Second Hospital of Lanzhou University(CY2023-MS-A03,Wei Wang).
文摘Circadian rhythm is a self-sustaining endogenous oscillation that serves as an internal timekeeping mechanism adapted to the Earth’s 24-h rotational schedule.It exists ubiquitously in nearly all organisms,from prokaryotes to mammals,and regulates diverse physiological and behavioral processes by synchronizing them with environmental fluctuations[1].Previous reports indicated that circadian rhythms exist in biological individuals and cells cultured in vitro[2].The mammalian circadian rhythm system consists of a central pacemaker located in the suprachiasmatic nucleus(SCN)of the hypothalamus,which coordinates peripheral rhythms through the sympathetic and parasympathetic nervous systems[3].This hierarchical mechanism uses neural populations as optimal models for circadian rhythm research.
