The microstructure evolution of a new directionally solidified（DS） Ni-based superalloy used for gas turbine blades after long-term aging at 950 ℃ was investigated.The results show that the γ ＇ phase becomes more ...The microstructure evolution of a new directionally solidified（DS） Ni-based superalloy used for gas turbine blades after long-term aging at 950 ℃ was investigated.The results show that the γ ＇ phase becomes more regular in dendritic arm and interdendritic area,while both the mass fraction and the size of γ ＇ phase increase gradually with increasing aging time.During long-term aging,the MC carbide dissolves on the edge to provide the carbon for the formation of M23C6 carbide by the precipitation of Cr at the grain boundary.The rose-shaped γ ＇/γ eutectic partly dissolves into γ matrix and the aging promotes it transform into raft-shape γ ＇.The microstructure is generally stable and no needle-like topologically close-packed phase（TCP） can be found after aging for 1 000 h.展开更多
The relationship among B content,microstructure evolution and stress rupture properties of K4750 alloy during long-term aging were investigated.After aging at 800℃for 1000 h,the decomposition degree of MC carbides of...The relationship among B content,microstructure evolution and stress rupture properties of K4750 alloy during long-term aging were investigated.After aging at 800℃for 1000 h,the decomposition degree of MC carbides of K4750 alloys with 0 B,0.007 wt.%B and 0.010 wt.%B were basically identical,which indicated that B has no inhibition on MC carbide decomposition during long-term aging.The MC carbide decomposition was accompanied by the formation of M_(23)C_(6) carbides and a small number ofηphases,which was controlled by the outward diffusion of C and Ti combined with the inward diffusion of Ni and Cr from theγmatrix.In addition,M_(23)C_(6) carbides in boron-free alloy were in continuous chain and needle-likeηphases were precipitated near them,while M_(23)C_(6) carbides in boron-containing alloys remained in granular distribution and noηphases precipitation around them.Adding B could delay the agglomeration and coarsening of M_(23)C_(6) carbides during long-term aging,which was because the segregation of B at grain boundary retarded the diffusion of alloy elements,thus weakened the local fluctuation of chemical composition near grain boundary.The stress rupture samples of K4750 alloys with various B contents after aging at 800℃for 1000 h were tested at 750℃/380 MPa.The results indicated that the stress rupture properties of bo ron-containing alloys were significantly better than that of boron-free alloy,which could be attributed to the increase of grain boundary cohesion strength and the optimization of M_(23)C_(6) carbide distribution due to the addition of B.展开更多
Thermal stabilities of microstructure and mechanical property have been investigated on superalloy U720Li, which is of great interest of application for jet engine and land-based turbine disc. The results showed that,...Thermal stabilities of microstructure and mechanical property have been investigated on superalloy U720Li, which is of great interest of application for jet engine and land-based turbine disc. The results showed that, the primary and secondary gamma' particles maintain good thermal stability at 650 and 700 degreesC with aging time up to 3000 h, while the tertiary gamma' is apparently dependent on aging temperature and time. The tertiary gamma' particles undergo a procedure of coarsening, dissolution and eventually complete disappearance with the increasing of aging time and temperature. They exhibit unusual high sensibility upon aging temperature, which is attributed to the lattice misfit between the gamma' precipitates and the matrix in the alloy. The grain boundary phase M23C6 remains stable without forming of sigma phase even with aging time up to 3000 h at 700 degreesC. Microhardness decreases apparently with increasing aging time and aging temperature. Theoretical analysis based on dislocation mechanism indicates that the change of microhardness should be attributed to the evolution of the tertiary gamma' during aging.展开更多
In K4750 alloy,the evolution of grain boundary(GB)precipitates,including the degradation of blocky MC carbide particles and the precipitation of granular/needle-likeηphase particles,were observed after longterm aging...In K4750 alloy,the evolution of grain boundary(GB)precipitates,including the degradation of blocky MC carbide particles and the precipitation of granular/needle-likeηphase particles,were observed after longterm aging(LA)at 750℃for 8000 h.During MC degradation,the Ti and C released from the MC carbide combined with Ni and Cr,respectively,in theγ’matrix to formη-Ni_(3)Ti phase and Cr-rich M_(23)C_(6)carbide.Large amounts of granularηphase precipitated at GBs and the needle-likeηphase grew gradually from GBs toward the grain interior.Because of the growth of theηphase through absorbingγ’phase,γ-depleted zones were formed around theηphase.The evolution of the MC carbide andηphase was primarily responsible for the decrease of the stress rupture life and the increase of elongation.After an LA sample was tested at 750℃and 360 MPa,the residual strain distribution was investigated by electron backscatter diffraction(EBSD).The results showed that the residual strain mainly distributed at GBs,especially in the region of MC degradation and at the edges ofηphases,which was closely related to the appearance of phase interfaces.Microvoids/cracks easily initiated at phase interfaces,then easily extended along theγ-depleted zones,thus the stress rupture life of LA samples was substantially shorter than that of samples subjected to the standard treatment.In particular,because of large amounts of fine degraded MC,granular M_(23)C_(6)and granularηphase particles distributed at GBs after 750℃/8000 h LA and microvoid/crack formation could be hindered by the formation of dimples,which led to an increase of elongation.展开更多
The service performance of heat resistance steels is largely determined by the precipitation kinetics.The nucleation-growth-coarsening behaviors of precipitates in G115 martensitic heat resistance steel during long-te...The service performance of heat resistance steels is largely determined by the precipitation kinetics.The nucleation-growth-coarsening behaviors of precipitates in G115 martensitic heat resistance steel during long-term aging at 650℃ have been systemically investigated.The microstructural characteristics,precipitate morphology and alloying element distribution were studied by scanning electron microscopy,transmission electron microscopy and scanning transmission electron microscopy.The lognormal distribution fitting combined with the multiple regression analysis was adopted to evaluate the precipitate size distributions.Laves phase has longer incubation time,and its coarsening rate is almost one order of magnitude higher in comparison with that of M_(23)C_(6) carbide.Furthermore,the nucleation rate,number density,average radius,and volume fraction of two precipitates are simulated based on the classical nucleation theory and the modified Langer-Schwartz model.The precipitation behavior of Laves phase can be well explained with the Fe-W system as the interfacial energy takes 0.10 J/m^(2).In contrast,the simulation results of M_(23)C_(6) carbide in the Fe-Cr-C system are significantly overestimated,which results from the inhibitory effect of boron on coarsening.展开更多
Microstructure evolution and the changes in mechanical properties of HR3 Csteel during long-term aging at650,700 and 750℃ were investigated.The precipitated phases of the aging steel included M23C6 carbides,Z-phase a...Microstructure evolution and the changes in mechanical properties of HR3 Csteel during long-term aging at650,700 and 750℃ were investigated.The precipitated phases of the aging steel included M23C6 carbides,Z-phase and a trace amount of Nb（C,N）.The M23C6 carbides were distributed mainly at the grain boundary,while Z-phase was mainly inside the grains.Amounts of both M23C6 carbides and Z-phase during the aging process increased with increasing aging period and temperature.Coarsening of M23C6 carbides was influenced significantly by aging time and temperature,while the size of the Z-phase was relatively less affected by the aging time and temperature,which had a steady strengthening effect.Coarsening of the M23C6 carbides was the main reason for the decline in high temperature yield strength during long-term aging at 750℃.The M23C6 carbides were linked into a continuous chain along the grain boundary which accounted for the decrease of toughness during aging.展开更多
Aging of polyaluminum chloride(PACl) coagulants could significantly influence hydrolyzed Al speciation ruling coagulation performance.The goal of this study was to investigate Al species transformation through long-te...Aging of polyaluminum chloride(PACl) coagulants could significantly influence hydrolyzed Al speciation ruling coagulation performance.The goal of this study was to investigate Al species transformation through long-term aging and its impact on coagulation performance.Two kinds of commercial coagulants(PACl-1 and PACl-2) were stored for in-situ aging tests in six months to evaluate Al species variation with time and the performance of coagulation with natural turbid waters.The results showed that CaSO4 precipitation easily occur in a commercial PACl coagulant with time as it contains SO4^2- and Ca^2+.It also activates the precipitation of gibbsite Al(OH)3 in PACl with aging.Through 180 days aging,both monomeric Al(Ala) and polymeric Al(Alb) substantially transform into colloidal Al(Alc) and precipitated for both PACl coagulants.At low turbidity(10 NTU),PACl-1 has a superior turbidity reduction rate than PACl-2,while PACl-2 performs a little better turbidity re duction at high turbidity(1000 NTU) regardless of aging time.With aging time,an obvious decrease in turbidity reduction for PACl-1 coagulation is observed at low turbidity of 10 NTU,while the improvement in turbidity reduction for PACl-2 coagulation by enhanced sweep flocculation can be achieved as Alb mostly transform into Alc after 150 days aging.It is concluded that dominant in-situ formed Alc after a long time hydrolysis can improve PACl coagulation efficiency in turbidity reduction by enhanced sweep flocculation,especially for low turbidity water,but the increase in preformed Alc in PACl would worsen particle destabilization after aging.展开更多
Microstructures of a CuZnAlMnNi shape memory alloy in the as-quenched andlong-term aged conditions were investigated by transmission electron microscopy. Aged for one yearin martensite phase, an equilibrium α-phase w...Microstructures of a CuZnAlMnNi shape memory alloy in the as-quenched andlong-term aged conditions were investigated by transmission electron microscopy. Aged for one yearin martensite phase, an equilibrium α-phase with fcc structure was observed in the M18R martensitematrix, accompanied by the appearance of a novel diffraction pattern. By analysis, it was suggestedthat the novel pattern results from the α-phase and the martensite matrix remaining in seven fineplates which produce intense secondary diffraction effect when the diffraction beams enter from onephase into another.展开更多
In view of developing novel alloys for applications in supercritical water-cooled reactor fuel cladding and in-core components, a 12%Cr reduced activation ferrite/martensite(RAFM) steel with good corrosion resistance ...In view of developing novel alloys for applications in supercritical water-cooled reactor fuel cladding and in-core components, a 12%Cr reduced activation ferrite/martensite(RAFM) steel with good corrosion resistance and irradiation performance was developed. V and Ta were added to form fine MX type carbonitrides and enhance the high temperature creep rupture strength. Microstructure stability of the steel during long-term aging at 650 C was studied experimentally combined with the simulation of ThermoCalc and DICTRA software. The results show that the precipitates in the steel during long-term aging contain M23C6, MX and Laves phase. M23C6 carbides play a major role in the stabilization of the tempered martensite lath structure by exerting a large Zener pinning force as compared with MX and Laves phase.Adding V and Ta in the steel can not only promote MX precipitation, but also refine M23C6 carbides and thus improve the thermal stability of lath/subgrains, which is beneficial to the improvement of high temperature microstructure stability of the 12%Cr RAFM steel.展开更多
The effects of electric field intensity and treatment temperature on the microstructures of GH4199 superalloy after long-term aging were investigated. The results show that the number and size of carbides and TCP(σph...The effects of electric field intensity and treatment temperature on the microstructures of GH4199 superalloy after long-term aging were investigated. The results show that the number and size of carbides and TCP(σphase andμphase) phase in the alloy increase with increasing electric field intensity at the same heat treatment temperature and holding time. While the number and size of carbides and TCP phase are weekly influenced by treatment temperature with lower electric field intensity of 2 kV/cm. When the treat temperature is up to 1 093 K, annealing twins appear in the alloy, and the number of twins increases with increasing holding time. Since the electric field can provide the enough energy for the movement of vacancies and atom, it is considered that the nucleus of the twins formed with formation stack faults due to the mismatch of local atom in crystal caused by the vacancies, and the twins will grow with the increase of holding time. Meanwhile, such promoting effects on atom movement of the electric field increase with the increase of the electric field intensity, meantime the carbides and TCP phase grow fast with the increase of electric field intensity.展开更多
SKI family transcriptional corepressor 1(SKOR1also known as LbxCor1, Fussel15, or CORL1), is a member of the SKI family of proteins and is transcribed from a protein-coding gene located on chromosome 15 in humans, tha...SKI family transcriptional corepressor 1(SKOR1also known as LbxCor1, Fussel15, or CORL1), is a member of the SKI family of proteins and is transcribed from a protein-coding gene located on chromosome 15 in humans, that has a molecular weight of approximately 100 kDa. Skor1 is highly expressed in neurons in the central nervous system of both humans and rodents.展开更多
In modern ZnO varistors,traditional aging mechanisms based on increased power consumption are no longer relevant due to reduced power consumption during DC aging.Prolonged exposure to both AC and DC voltages results i...In modern ZnO varistors,traditional aging mechanisms based on increased power consumption are no longer relevant due to reduced power consumption during DC aging.Prolonged exposure to both AC and DC voltages results in increased leakage current,decreased breakdown voltage,and lower nonlinearity,ultimately compromising their protective performance.To investigate the evolution in electrical properties during DC aging,this work developed a finite element model based on Voronoi networks and conducted accelerated aging tests on commercial varistors.Throughout the aging process,current-voltage characteristics and Schottky barrier parameters were measured and analyzed.The results indicate that when subjected to constant voltage,current flows through regions with larger grain sizes,forming discharge channels.As aging progresses,the current focus increases on these channels,leading to a decline in the varistor’s overall performance.Furthermore,analysis of the Schottky barrier parameters shows that the changes in electrical performance during aging are non-monotonic.These findings offer theoretical support for understanding the aging mechanisms and condition assessment of modern stable ZnO varistors.展开更多
Aging is a physiological and complex process produced by accumulative age-dependent cellular damage,which significantly impacts brain regions like the hippocampus,an essential region involved in memory and learning.A ...Aging is a physiological and complex process produced by accumulative age-dependent cellular damage,which significantly impacts brain regions like the hippocampus,an essential region involved in memory and learning.A crucial factor contributing to this decline is the dysfunction of mitochondria,particularly those located at synapses.Synaptic mitochondria are specialized organelles that produce the energy required for synaptic transmission but are also important for calcium homeostasis at these sites.In contrast,non-synaptic mitochondria primarily involve cellular metabolism and long-term energy supply.Both pools of mitochondria differ in their form,proteome,functionality,and cellular role.The proper functioning of synaptic mitochondria depends on processes such as mitochondrial dynamics,transport,and quality control.However,synaptic mitochondria are particularly vulnerable to age-associated damage,characterized by oxidative stress,impaired energy production,and calcium dysregulation.These changes compromise synaptic transmission,reducing synaptic activity and cognitive decline during aging.In the context of neurodegenerative diseases such as Alzheimer’s,Parkinson’s,and Huntington’s,the decline of synaptic mitochondrial function is even more pronounced.These diseases are marked by pathological protein accumulation,disrupted mitochondrial dynamics,and heightened oxidative stress,accelerating synaptic dysfunction and neuronal loss.Due to their specialized role and location,synaptic mitochondria are among the first organelles to exhibit dysfunction,underscoring their critical role in disease progression.This review delves into the main differences at structural and functional levels between synaptic and non-synaptic mitochondria,emphasizing the vulnerability of synaptic mitochondria to the aging process and neurodegeneration.These approaches highlight the potential of targeting synaptic mitochondria to mitigate age-associated cognitive impairment and synaptic degeneration.This review emphasizes the distinct vulnerabilities of hippocampal synaptic mitochondria,highlighting their essential role in sustaining brain function throughout life and their promise as therapeutic targets for safeguarding the cognitive capacities of people of advanced age.展开更多
Objective:To investigate the long-term prognosis and postoperative cosmetic outcomes of breast-conserving surgery combined with sentinel lymph node biopsy in patients with early-stage breast cancer,providing a referen...Objective:To investigate the long-term prognosis and postoperative cosmetic outcomes of breast-conserving surgery combined with sentinel lymph node biopsy in patients with early-stage breast cancer,providing a reference for the selection of clinical treatment plans.Methods:A retrospective analysis was conducted on the clinical data of 68 patients with early-stage breast cancer admitted from January 2022 to December 2025.Based on the surgical approach,patients were divided into an observation group(breast-conserving surgery+sentinel lymph node biopsy)and a control group(other surgical methods such as modified radical mastectomy/total mastectomy).Clinical and pathological characteristics,incidence of postoperative complications,follow-up prognosis,and satisfaction with cosmetic outcomes were compared between the two groups.Results:Among the 68 patients,41 were in the observation group and 27 in the control group.The average age of patients in the observation group was(54.32±8.15)years,while that in the control group was(62.45±9.76)years.The average tumor size in the observation group was(1.86±0.72)cm,compared to(3.21±1.45)cm in the control group.The incidence of postoperative complications in the observation group was 9.76%,significantly lower than that in the control group at 33.33%(P<0.05).The 6-month disease-free survival rate was 95.12%in the observation group and 88.89%in the control group,with no statistically significant difference between the two groups(P>0.05).The excellent and good rate of cosmetic outcomes in the observation group was 87.80%,significantly higher than that in the control group at 29.63%(P<0.05).Conclusion:Breast-conserving surgery combined with sentinel lymph node biopsy for early-stage breast cancer can achieve long-term prognostic outcomes comparable to those of traditional radical surgery,with the advantages of fewer postoperative complications and superior cosmetic results.This approach is worthy of clinical promotion and application,particularly for early-stage breast cancer patients who have a demand for preserving breast morphology.展开更多
As the aging population continues to grow,age-related health issues are becoming increasingly prominent,attracting widespread attention and concern from society.While research on the mechanisms of aging is relatively ...As the aging population continues to grow,age-related health issues are becoming increasingly prominent,attracting widespread attention and concern from society.While research on the mechanisms of aging is relatively extensive,studies on the association between aging and related diseases remain limited.G.lucidum,a traditional medicinal fungus,has garnered significant attention due to its diverse bioactive properties.Recent studies have revealed that G.lucidum and its active components exhibit significant potential in anti-aging and regulating dysregulation of glucose and lipid metabolism.However,a comprehensive and detailed review of recent research findings has yet to be thoroughly explored.This paper summarizes and elucidates the latest advances in the pathological mechanisms of aging-related glucose and lipid metabolism disorders by retrieving data from databases such as X-mol and PubMed,provides a detailed account of the regulatory effects of G.lucidum’s primary active components on aging and lipid metabolism,and explores their potential mechanisms.Additionally,it discusses the application prospects of G.lucidum in the fields of anti-aging and metabolic regulation,aiming to provide a reference for research on aging-mediated lipid metabolism disorders and to lay a theoretical foundation for the further development and application of G.lucidum.展开更多
The study evaluated the skin anti-aging activity of Astragalus sarcocolla leaves extract(ASE)by assessing its antioxidant and inhibitory effect activity on matrix metalloproteinase(MMP),collagenase,elastase,hyaluronid...The study evaluated the skin anti-aging activity of Astragalus sarcocolla leaves extract(ASE)by assessing its antioxidant and inhibitory effect activity on matrix metalloproteinase(MMP),collagenase,elastase,hyaluronidase,and tyrosinase in relation to its chemical composition.Ultra Performance Liquid Chromatography-Mass Spectrometry(UPLC-MS)identified 27 metabolites(15 flavonoids,8 phenolic acids and their derivatives,and 4 coumarins).ASE showed strong antioxidant capacity in DPPH(IC_(50)value of 26.05μg/mL)and FRAP(2433μM FeSO_(4)/g extract)assays.The extract inhibited MMP-1 and MMP-9 in a concentration-dependent manner and suppressed collagenase,elastase,hyaluronidase,and tyrosinase activities(IC_(50)=35.038,40.748,61.389,and 30.980μg/mL,respectively).A network pharmacology study was conducted to uncover the mechanisms responsible for skin anti-aging effects,and molecular docking further evaluated interactions of key metabolites with hub targets.Twenty-one bioactive metabolites,selected based on oral bioavailability and drug-likeness,highlighted cinnamic acid,acacetin,luteolin,kaempferol,and apigenin as key compounds.MMP-9,ESR1,PTGS-2,and EGFR were identified as main targets.Docking studies revealed that acacetin and apigenin have stronger binding affinities to MMP-9,PTGS-2,and EGFR than other constituents.These findings suggest that ASE may serve as a natural multi-target skin anti-aging remedy with potential cosmetic applications.展开更多
Mitochondrial dysfunction and oxidative stress are widely regarded as primary drivers of aging and are associated with several neurodegenerative diseases.The degeneration of motor neurons during aging is a critical pa...Mitochondrial dysfunction and oxidative stress are widely regarded as primary drivers of aging and are associated with several neurodegenerative diseases.The degeneration of motor neurons during aging is a critical pathological factor contributing to the progression of sarcopenia.However,the morphological and functional changes in mitochondria and their interplay in the degeneration of the neuromuscular junction during aging remain poorly understood.A defined systematic search of the Pub Med,Web of Science and Embase databases(last accessed on October 30,2024)was conducted with search terms including'mitochondria','aging'and'NMJ'.Clinical and preclinical studies of mitochondrial dysfunction and neuromuscular junction degeneration during aging.Twentyseven studies were included in this systematic review.This systematic review provides a summary of morphological,functional and biological changes in neuromuscular junction,mitochondrial morphology,biosynthesis,respiratory chain function,and mitophagy during aging.We focus on the interactions and mechanisms underlying the relationship between mitochondria and neuromuscular junctions during aging.Aging is characterized by significant reductions in mitochondrial fusion/fission cycles,biosynthesis,and mitochondrial quality control,which may lead to neuromuscular junction dysfunction,denervation and poor physical performance.Motor nerve terminals that exhibit redox sensitivity are among the first to exhibit abnormalities,ultimately leading to an early decline in muscle strength through impaired neuromuscular junction transmission function.Parg coactivator 1 alpha is a crucial molecule that regulates mitochondrial biogenesis and modulates various pathways,including the mitochondrial respiratory chain,energy deficiency,oxidative stress,and inflammation.Mitochondrial dysfunction is correlated with neuromuscular junction denervation and acetylcholine receptor fragmentation,resulting in muscle atrophy and a decrease in strength during aging.Physical therapy,pharmacotherapy,and gene therapy can alleviate the structural degeneration and functional deterioration of neuromuscular junction by restoring mitochondrial function.Therefore,mitochondria are considered potential targets for preserving neuromuscular junction morphology and function during aging to treat sarcopenia.展开更多
A multistage solution treatment process was applied for nickel-based single crystal superalloys,complemented by various aging durations and cooling rates.The microstructure was characterized by scanning electron micro...A multistage solution treatment process was applied for nickel-based single crystal superalloys,complemented by various aging durations and cooling rates.The microstructure was characterized by scanning electron microscopy(SEM)to observe the γ'phase.Additionally,phase field simulations were conducted to model the growth ofγ'precipitates during aging and analyze their morphological evolution.The experimental results demonstrated that the multistage solution treatment effectively eliminated eutectic phases and carbides.Moreover,samples aged for 10 min exhibited larger and more rectangularγ'precipitates compared with those aged for 5 min.Notably,secondary γ'precipitates were observed in samples subjected to water cooling.Two indices for quantifying rectangularization were proposed and successfully applied.Based on the simulation results,lattice mismatch induced coherency stresses and elevated stress triaxiality along the <111> direction contributed to the rectangularization of theγ'phase.展开更多
In recent years,rising life expectancy has led to a significant increase in the prevalence of neurodegenerative disorders,including Alzheimer’s disease(AD),Parkinson’s disease,and age-related cognitive decline.Addit...In recent years,rising life expectancy has led to a significant increase in the prevalence of neurodegenerative disorders,including Alzheimer’s disease(AD),Parkinson’s disease,and age-related cognitive decline.Additionally,other neurological conditions such as glioblastoma,the most common and aggressive brain tumor in adults have been more frequently reported in aging populations.The brain itself is highly vulnerable to age-related changes,particularly disruptions in homeostatic regulation,which further contribute to its functional decline and heightened susceptibility to disease.This has led to a surge of interest in understanding the cellular and molecular mechanisms driving these changes.展开更多
Regenerative medicine is a promising therapeutic avenue for previously incurable diseases.As the risk of chronic and degenerative diseases significantly increases with age,the elderly population represents a major coh...Regenerative medicine is a promising therapeutic avenue for previously incurable diseases.As the risk of chronic and degenerative diseases significantly increases with age,the elderly population represents a major cohort for stem cell-based therapies.However,the regenerative potential of stem cells significantly decreases with advanced age and deteriorating health status of the donor.Therefore,the efficacy of autologous stem cell therapy is significantly compromised in older patients.To overcome these limitations,alternative strategies have been used to restore the age-and disease-depleted function of stem cells.These methods aim to restore the therapeutic efficacy of aged stem cells for autologous use.This article explores the effect of donor age and health status on the regenerative potential of stem cells.It further highlights the limitations of stem cell-based therapy for autologous treatment in the elderly.A comprehensive insight into the potential strategies to address the“age”and“disease”compromised regenerative potential of autologous stem cells is also presented.The information provided here serves as a valuable resource for physicians and patients for optimization of stem cellbased autologous therapy for aged patients.展开更多
基金Projects(2006CB605005,2010CB631203) supported by the National Basic Research Program of ChinaProject(IRT0713) supported by Changjiang Scholars and Innovative Research Team in University,China
文摘The microstructure evolution of a new directionally solidified（DS） Ni-based superalloy used for gas turbine blades after long-term aging at 950 ℃ was investigated.The results show that the γ ＇ phase becomes more regular in dendritic arm and interdendritic area,while both the mass fraction and the size of γ ＇ phase increase gradually with increasing aging time.During long-term aging,the MC carbide dissolves on the edge to provide the carbon for the formation of M23C6 carbide by the precipitation of Cr at the grain boundary.The rose-shaped γ ＇/γ eutectic partly dissolves into γ matrix and the aging promotes it transform into raft-shape γ ＇.The microstructure is generally stable and no needle-like topologically close-packed phase（TCP） can be found after aging for 1 000 h.
文摘The relationship among B content,microstructure evolution and stress rupture properties of K4750 alloy during long-term aging were investigated.After aging at 800℃for 1000 h,the decomposition degree of MC carbides of K4750 alloys with 0 B,0.007 wt.%B and 0.010 wt.%B were basically identical,which indicated that B has no inhibition on MC carbide decomposition during long-term aging.The MC carbide decomposition was accompanied by the formation of M_(23)C_(6) carbides and a small number ofηphases,which was controlled by the outward diffusion of C and Ti combined with the inward diffusion of Ni and Cr from theγmatrix.In addition,M_(23)C_(6) carbides in boron-free alloy were in continuous chain and needle-likeηphases were precipitated near them,while M_(23)C_(6) carbides in boron-containing alloys remained in granular distribution and noηphases precipitation around them.Adding B could delay the agglomeration and coarsening of M_(23)C_(6) carbides during long-term aging,which was because the segregation of B at grain boundary retarded the diffusion of alloy elements,thus weakened the local fluctuation of chemical composition near grain boundary.The stress rupture samples of K4750 alloys with various B contents after aging at 800℃for 1000 h were tested at 750℃/380 MPa.The results indicated that the stress rupture properties of bo ron-containing alloys were significantly better than that of boron-free alloy,which could be attributed to the increase of grain boundary cohesion strength and the optimization of M_(23)C_(6) carbide distribution due to the addition of B.
文摘Thermal stabilities of microstructure and mechanical property have been investigated on superalloy U720Li, which is of great interest of application for jet engine and land-based turbine disc. The results showed that, the primary and secondary gamma' particles maintain good thermal stability at 650 and 700 degreesC with aging time up to 3000 h, while the tertiary gamma' is apparently dependent on aging temperature and time. The tertiary gamma' particles undergo a procedure of coarsening, dissolution and eventually complete disappearance with the increasing of aging time and temperature. They exhibit unusual high sensibility upon aging temperature, which is attributed to the lattice misfit between the gamma' precipitates and the matrix in the alloy. The grain boundary phase M23C6 remains stable without forming of sigma phase even with aging time up to 3000 h at 700 degreesC. Microhardness decreases apparently with increasing aging time and aging temperature. Theoretical analysis based on dislocation mechanism indicates that the change of microhardness should be attributed to the evolution of the tertiary gamma' during aging.
基金supported by the National Natural Science Foundation of China under Grant No.52001314the Natural Science Foundation of Liaoning Province of China under Grant No.2020BS-008the China Postdoctoral Science Foundation under Grant No.2020M671403。
文摘In K4750 alloy,the evolution of grain boundary(GB)precipitates,including the degradation of blocky MC carbide particles and the precipitation of granular/needle-likeηphase particles,were observed after longterm aging(LA)at 750℃for 8000 h.During MC degradation,the Ti and C released from the MC carbide combined with Ni and Cr,respectively,in theγ’matrix to formη-Ni_(3)Ti phase and Cr-rich M_(23)C_(6)carbide.Large amounts of granularηphase precipitated at GBs and the needle-likeηphase grew gradually from GBs toward the grain interior.Because of the growth of theηphase through absorbingγ’phase,γ-depleted zones were formed around theηphase.The evolution of the MC carbide andηphase was primarily responsible for the decrease of the stress rupture life and the increase of elongation.After an LA sample was tested at 750℃and 360 MPa,the residual strain distribution was investigated by electron backscatter diffraction(EBSD).The results showed that the residual strain mainly distributed at GBs,especially in the region of MC degradation and at the edges ofηphases,which was closely related to the appearance of phase interfaces.Microvoids/cracks easily initiated at phase interfaces,then easily extended along theγ-depleted zones,thus the stress rupture life of LA samples was substantially shorter than that of samples subjected to the standard treatment.In particular,because of large amounts of fine degraded MC,granular M_(23)C_(6)and granularηphase particles distributed at GBs after 750℃/8000 h LA and microvoid/crack formation could be hindered by the formation of dimples,which led to an increase of elongation.
基金financially supported by the National Key Research and Development Program of China(Grant Nos.2020YFB0311000 and 2017YFB0305201)the Fund of Key Laboratory of Advanced Materials of Ministry of Education(ADV22-12)the Jiangsu Funding Program for Excellent Postdoctoral Talent.
文摘The service performance of heat resistance steels is largely determined by the precipitation kinetics.The nucleation-growth-coarsening behaviors of precipitates in G115 martensitic heat resistance steel during long-term aging at 650℃ have been systemically investigated.The microstructural characteristics,precipitate morphology and alloying element distribution were studied by scanning electron microscopy,transmission electron microscopy and scanning transmission electron microscopy.The lognormal distribution fitting combined with the multiple regression analysis was adopted to evaluate the precipitate size distributions.Laves phase has longer incubation time,and its coarsening rate is almost one order of magnitude higher in comparison with that of M_(23)C_(6) carbide.Furthermore,the nucleation rate,number density,average radius,and volume fraction of two precipitates are simulated based on the classical nucleation theory and the modified Langer-Schwartz model.The precipitation behavior of Laves phase can be well explained with the Fe-W system as the interfacial energy takes 0.10 J/m^(2).In contrast,the simulation results of M_(23)C_(6) carbide in the Fe-Cr-C system are significantly overestimated,which results from the inhibitory effect of boron on coarsening.
基金Item Sponsored by National High-Tech Research and Development Program(863Program)of China(2012AA03A501)International Science and Technology Cooperation Program of China(2012DFG51670)
文摘Microstructure evolution and the changes in mechanical properties of HR3 Csteel during long-term aging at650,700 and 750℃ were investigated.The precipitated phases of the aging steel included M23C6 carbides,Z-phase and a trace amount of Nb（C,N）.The M23C6 carbides were distributed mainly at the grain boundary,while Z-phase was mainly inside the grains.Amounts of both M23C6 carbides and Z-phase during the aging process increased with increasing aging period and temperature.Coarsening of M23C6 carbides was influenced significantly by aging time and temperature,while the size of the Z-phase was relatively less affected by the aging time and temperature,which had a steady strengthening effect.Coarsening of the M23C6 carbides was the main reason for the decline in high temperature yield strength during long-term aging at 750℃.The M23C6 carbides were linked into a continuous chain along the grain boundary which accounted for the decrease of toughness during aging.
基金the assistances from Taiwan Water Corporation in sampling as well as the financial support。
文摘Aging of polyaluminum chloride(PACl) coagulants could significantly influence hydrolyzed Al speciation ruling coagulation performance.The goal of this study was to investigate Al species transformation through long-term aging and its impact on coagulation performance.Two kinds of commercial coagulants(PACl-1 and PACl-2) were stored for in-situ aging tests in six months to evaluate Al species variation with time and the performance of coagulation with natural turbid waters.The results showed that CaSO4 precipitation easily occur in a commercial PACl coagulant with time as it contains SO4^2- and Ca^2+.It also activates the precipitation of gibbsite Al(OH)3 in PACl with aging.Through 180 days aging,both monomeric Al(Ala) and polymeric Al(Alb) substantially transform into colloidal Al(Alc) and precipitated for both PACl coagulants.At low turbidity(10 NTU),PACl-1 has a superior turbidity reduction rate than PACl-2,while PACl-2 performs a little better turbidity re duction at high turbidity(1000 NTU) regardless of aging time.With aging time,an obvious decrease in turbidity reduction for PACl-1 coagulation is observed at low turbidity of 10 NTU,while the improvement in turbidity reduction for PACl-2 coagulation by enhanced sweep flocculation can be achieved as Alb mostly transform into Alc after 150 days aging.It is concluded that dominant in-situ formed Alc after a long time hydrolysis can improve PACl coagulation efficiency in turbidity reduction by enhanced sweep flocculation,especially for low turbidity water,but the increase in preformed Alc in PACl would worsen particle destabilization after aging.
基金This project is financially supported by the Natural Science Foundation of Shandong Province ( Y2001F06) and the Fund for Outstanding Young Researcher of Shandong Province
文摘Microstructures of a CuZnAlMnNi shape memory alloy in the as-quenched andlong-term aged conditions were investigated by transmission electron microscopy. Aged for one yearin martensite phase, an equilibrium α-phase with fcc structure was observed in the M18R martensitematrix, accompanied by the appearance of a novel diffraction pattern. By analysis, it was suggestedthat the novel pattern results from the α-phase and the martensite matrix remaining in seven fineplates which produce intense secondary diffraction effect when the diffraction beams enter from onephase into another.
基金supported by the National Basic Research Program of China (Grant No. 2007CB209801)the National Natural Science Fundation of China (Grant No. 51371030)the National High Technology Research and Development Program of China (Grant No. 2013AA031601)
文摘In view of developing novel alloys for applications in supercritical water-cooled reactor fuel cladding and in-core components, a 12%Cr reduced activation ferrite/martensite(RAFM) steel with good corrosion resistance and irradiation performance was developed. V and Ta were added to form fine MX type carbonitrides and enhance the high temperature creep rupture strength. Microstructure stability of the steel during long-term aging at 650 C was studied experimentally combined with the simulation of ThermoCalc and DICTRA software. The results show that the precipitates in the steel during long-term aging contain M23C6, MX and Laves phase. M23C6 carbides play a major role in the stabilization of the tempered martensite lath structure by exerting a large Zener pinning force as compared with MX and Laves phase.Adding V and Ta in the steel can not only promote MX precipitation, but also refine M23C6 carbides and thus improve the thermal stability of lath/subgrains, which is beneficial to the improvement of high temperature microstructure stability of the 12%Cr RAFM steel.
文摘The effects of electric field intensity and treatment temperature on the microstructures of GH4199 superalloy after long-term aging were investigated. The results show that the number and size of carbides and TCP(σphase andμphase) phase in the alloy increase with increasing electric field intensity at the same heat treatment temperature and holding time. While the number and size of carbides and TCP phase are weekly influenced by treatment temperature with lower electric field intensity of 2 kV/cm. When the treat temperature is up to 1 093 K, annealing twins appear in the alloy, and the number of twins increases with increasing holding time. Since the electric field can provide the enough energy for the movement of vacancies and atom, it is considered that the nucleus of the twins formed with formation stack faults due to the mismatch of local atom in crystal caused by the vacancies, and the twins will grow with the increase of holding time. Meanwhile, such promoting effects on atom movement of the electric field increase with the increase of the electric field intensity, meantime the carbides and TCP phase grow fast with the increase of electric field intensity.
基金supported by Science Foundation Ireland (Grant 19/FFP/6666),Cure Parkinson’s (Grant CP:GO01)a PhD studentship from the Anatomical Society。
文摘SKI family transcriptional corepressor 1(SKOR1also known as LbxCor1, Fussel15, or CORL1), is a member of the SKI family of proteins and is transcribed from a protein-coding gene located on chromosome 15 in humans, that has a molecular weight of approximately 100 kDa. Skor1 is highly expressed in neurons in the central nervous system of both humans and rodents.
文摘In modern ZnO varistors,traditional aging mechanisms based on increased power consumption are no longer relevant due to reduced power consumption during DC aging.Prolonged exposure to both AC and DC voltages results in increased leakage current,decreased breakdown voltage,and lower nonlinearity,ultimately compromising their protective performance.To investigate the evolution in electrical properties during DC aging,this work developed a finite element model based on Voronoi networks and conducted accelerated aging tests on commercial varistors.Throughout the aging process,current-voltage characteristics and Schottky barrier parameters were measured and analyzed.The results indicate that when subjected to constant voltage,current flows through regions with larger grain sizes,forming discharge channels.As aging progresses,the current focus increases on these channels,leading to a decline in the varistor’s overall performance.Furthermore,analysis of the Schottky barrier parameters shows that the changes in electrical performance during aging are non-monotonic.These findings offer theoretical support for understanding the aging mechanisms and condition assessment of modern stable ZnO varistors.
基金supported by ANID FONDECYT No.1221178Centro Ciencia&Vida,FB210008,Financiamiento Basal para Centros Científicos y Tecnológicos de Excelencia de ANID to CTR.
文摘Aging is a physiological and complex process produced by accumulative age-dependent cellular damage,which significantly impacts brain regions like the hippocampus,an essential region involved in memory and learning.A crucial factor contributing to this decline is the dysfunction of mitochondria,particularly those located at synapses.Synaptic mitochondria are specialized organelles that produce the energy required for synaptic transmission but are also important for calcium homeostasis at these sites.In contrast,non-synaptic mitochondria primarily involve cellular metabolism and long-term energy supply.Both pools of mitochondria differ in their form,proteome,functionality,and cellular role.The proper functioning of synaptic mitochondria depends on processes such as mitochondrial dynamics,transport,and quality control.However,synaptic mitochondria are particularly vulnerable to age-associated damage,characterized by oxidative stress,impaired energy production,and calcium dysregulation.These changes compromise synaptic transmission,reducing synaptic activity and cognitive decline during aging.In the context of neurodegenerative diseases such as Alzheimer’s,Parkinson’s,and Huntington’s,the decline of synaptic mitochondrial function is even more pronounced.These diseases are marked by pathological protein accumulation,disrupted mitochondrial dynamics,and heightened oxidative stress,accelerating synaptic dysfunction and neuronal loss.Due to their specialized role and location,synaptic mitochondria are among the first organelles to exhibit dysfunction,underscoring their critical role in disease progression.This review delves into the main differences at structural and functional levels between synaptic and non-synaptic mitochondria,emphasizing the vulnerability of synaptic mitochondria to the aging process and neurodegeneration.These approaches highlight the potential of targeting synaptic mitochondria to mitigate age-associated cognitive impairment and synaptic degeneration.This review emphasizes the distinct vulnerabilities of hippocampal synaptic mitochondria,highlighting their essential role in sustaining brain function throughout life and their promise as therapeutic targets for safeguarding the cognitive capacities of people of advanced age.
文摘Objective:To investigate the long-term prognosis and postoperative cosmetic outcomes of breast-conserving surgery combined with sentinel lymph node biopsy in patients with early-stage breast cancer,providing a reference for the selection of clinical treatment plans.Methods:A retrospective analysis was conducted on the clinical data of 68 patients with early-stage breast cancer admitted from January 2022 to December 2025.Based on the surgical approach,patients were divided into an observation group(breast-conserving surgery+sentinel lymph node biopsy)and a control group(other surgical methods such as modified radical mastectomy/total mastectomy).Clinical and pathological characteristics,incidence of postoperative complications,follow-up prognosis,and satisfaction with cosmetic outcomes were compared between the two groups.Results:Among the 68 patients,41 were in the observation group and 27 in the control group.The average age of patients in the observation group was(54.32±8.15)years,while that in the control group was(62.45±9.76)years.The average tumor size in the observation group was(1.86±0.72)cm,compared to(3.21±1.45)cm in the control group.The incidence of postoperative complications in the observation group was 9.76%,significantly lower than that in the control group at 33.33%(P<0.05).The 6-month disease-free survival rate was 95.12%in the observation group and 88.89%in the control group,with no statistically significant difference between the two groups(P>0.05).The excellent and good rate of cosmetic outcomes in the observation group was 87.80%,significantly higher than that in the control group at 29.63%(P<0.05).Conclusion:Breast-conserving surgery combined with sentinel lymph node biopsy for early-stage breast cancer can achieve long-term prognostic outcomes comparable to those of traditional radical surgery,with the advantages of fewer postoperative complications and superior cosmetic results.This approach is worthy of clinical promotion and application,particularly for early-stage breast cancer patients who have a demand for preserving breast morphology.
基金supported by grants from Natural Science Foundation of Jilin Province(No.23JQ08,No.YDZJ202502 CXJD077,No.JLARS-2025-0802-09 and No.YDZJ202501ZY TS706).
文摘As the aging population continues to grow,age-related health issues are becoming increasingly prominent,attracting widespread attention and concern from society.While research on the mechanisms of aging is relatively extensive,studies on the association between aging and related diseases remain limited.G.lucidum,a traditional medicinal fungus,has garnered significant attention due to its diverse bioactive properties.Recent studies have revealed that G.lucidum and its active components exhibit significant potential in anti-aging and regulating dysregulation of glucose and lipid metabolism.However,a comprehensive and detailed review of recent research findings has yet to be thoroughly explored.This paper summarizes and elucidates the latest advances in the pathological mechanisms of aging-related glucose and lipid metabolism disorders by retrieving data from databases such as X-mol and PubMed,provides a detailed account of the regulatory effects of G.lucidum’s primary active components on aging and lipid metabolism,and explores their potential mechanisms.Additionally,it discusses the application prospects of G.lucidum in the fields of anti-aging and metabolic regulation,aiming to provide a reference for research on aging-mediated lipid metabolism disorders and to lay a theoretical foundation for the further development and application of G.lucidum.
基金funded by the Deanship of Graduate Studies and Scientific Research at Jouf University under grant No.(DGSSR-2023-01-02126).
文摘The study evaluated the skin anti-aging activity of Astragalus sarcocolla leaves extract(ASE)by assessing its antioxidant and inhibitory effect activity on matrix metalloproteinase(MMP),collagenase,elastase,hyaluronidase,and tyrosinase in relation to its chemical composition.Ultra Performance Liquid Chromatography-Mass Spectrometry(UPLC-MS)identified 27 metabolites(15 flavonoids,8 phenolic acids and their derivatives,and 4 coumarins).ASE showed strong antioxidant capacity in DPPH(IC_(50)value of 26.05μg/mL)and FRAP(2433μM FeSO_(4)/g extract)assays.The extract inhibited MMP-1 and MMP-9 in a concentration-dependent manner and suppressed collagenase,elastase,hyaluronidase,and tyrosinase activities(IC_(50)=35.038,40.748,61.389,and 30.980μg/mL,respectively).A network pharmacology study was conducted to uncover the mechanisms responsible for skin anti-aging effects,and molecular docking further evaluated interactions of key metabolites with hub targets.Twenty-one bioactive metabolites,selected based on oral bioavailability and drug-likeness,highlighted cinnamic acid,acacetin,luteolin,kaempferol,and apigenin as key compounds.MMP-9,ESR1,PTGS-2,and EGFR were identified as main targets.Docking studies revealed that acacetin and apigenin have stronger binding affinities to MMP-9,PTGS-2,and EGFR than other constituents.These findings suggest that ASE may serve as a natural multi-target skin anti-aging remedy with potential cosmetic applications.
基金supported by grants from Collaborative Research Fund(Ref:C4032-21GF)General Research Grant(Ref:14114822)+1 种基金Group Research Scheme(Ref:3110146)Area of Excellence(Ref:Ao E/M-402/20)。
文摘Mitochondrial dysfunction and oxidative stress are widely regarded as primary drivers of aging and are associated with several neurodegenerative diseases.The degeneration of motor neurons during aging is a critical pathological factor contributing to the progression of sarcopenia.However,the morphological and functional changes in mitochondria and their interplay in the degeneration of the neuromuscular junction during aging remain poorly understood.A defined systematic search of the Pub Med,Web of Science and Embase databases(last accessed on October 30,2024)was conducted with search terms including'mitochondria','aging'and'NMJ'.Clinical and preclinical studies of mitochondrial dysfunction and neuromuscular junction degeneration during aging.Twentyseven studies were included in this systematic review.This systematic review provides a summary of morphological,functional and biological changes in neuromuscular junction,mitochondrial morphology,biosynthesis,respiratory chain function,and mitophagy during aging.We focus on the interactions and mechanisms underlying the relationship between mitochondria and neuromuscular junctions during aging.Aging is characterized by significant reductions in mitochondrial fusion/fission cycles,biosynthesis,and mitochondrial quality control,which may lead to neuromuscular junction dysfunction,denervation and poor physical performance.Motor nerve terminals that exhibit redox sensitivity are among the first to exhibit abnormalities,ultimately leading to an early decline in muscle strength through impaired neuromuscular junction transmission function.Parg coactivator 1 alpha is a crucial molecule that regulates mitochondrial biogenesis and modulates various pathways,including the mitochondrial respiratory chain,energy deficiency,oxidative stress,and inflammation.Mitochondrial dysfunction is correlated with neuromuscular junction denervation and acetylcholine receptor fragmentation,resulting in muscle atrophy and a decrease in strength during aging.Physical therapy,pharmacotherapy,and gene therapy can alleviate the structural degeneration and functional deterioration of neuromuscular junction by restoring mitochondrial function.Therefore,mitochondria are considered potential targets for preserving neuromuscular junction morphology and function during aging to treat sarcopenia.
基金supported by the Stable Support Project and the Major National Science and Technology Project,China(Nos.2017-Ⅶ-0008-0101,2017-Ⅵ-0003-0073)。
文摘A multistage solution treatment process was applied for nickel-based single crystal superalloys,complemented by various aging durations and cooling rates.The microstructure was characterized by scanning electron microscopy(SEM)to observe the γ'phase.Additionally,phase field simulations were conducted to model the growth ofγ'precipitates during aging and analyze their morphological evolution.The experimental results demonstrated that the multistage solution treatment effectively eliminated eutectic phases and carbides.Moreover,samples aged for 10 min exhibited larger and more rectangularγ'precipitates compared with those aged for 5 min.Notably,secondary γ'precipitates were observed in samples subjected to water cooling.Two indices for quantifying rectangularization were proposed and successfully applied.Based on the simulation results,lattice mismatch induced coherency stresses and elevated stress triaxiality along the <111> direction contributed to the rectangularization of theγ'phase.
基金supported by the Swedish ResearchCouncil and the Swedish Brain Foundation,theCancer Research Funds of Radiumhemmet,theStrategic Research Area in Cancer(StratCan),the Strategic Research Area in Neuroscience(StratNeuro),the Swedish Cancer Society,theSwedish Childhood Cancer Foundation,theKarolinska Institutet Foundation,the InnoHKinitiative of the Innovation and TechnologyCommission of the Hong Kong SpecialAdministrative Region Government(to BJ).Openaccess funding is provided by the KarolinskaInstitute.
文摘In recent years,rising life expectancy has led to a significant increase in the prevalence of neurodegenerative disorders,including Alzheimer’s disease(AD),Parkinson’s disease,and age-related cognitive decline.Additionally,other neurological conditions such as glioblastoma,the most common and aggressive brain tumor in adults have been more frequently reported in aging populations.The brain itself is highly vulnerable to age-related changes,particularly disruptions in homeostatic regulation,which further contribute to its functional decline and heightened susceptibility to disease.This has led to a surge of interest in understanding the cellular and molecular mechanisms driving these changes.
文摘Regenerative medicine is a promising therapeutic avenue for previously incurable diseases.As the risk of chronic and degenerative diseases significantly increases with age,the elderly population represents a major cohort for stem cell-based therapies.However,the regenerative potential of stem cells significantly decreases with advanced age and deteriorating health status of the donor.Therefore,the efficacy of autologous stem cell therapy is significantly compromised in older patients.To overcome these limitations,alternative strategies have been used to restore the age-and disease-depleted function of stem cells.These methods aim to restore the therapeutic efficacy of aged stem cells for autologous use.This article explores the effect of donor age and health status on the regenerative potential of stem cells.It further highlights the limitations of stem cell-based therapy for autologous treatment in the elderly.A comprehensive insight into the potential strategies to address the“age”and“disease”compromised regenerative potential of autologous stem cells is also presented.The information provided here serves as a valuable resource for physicians and patients for optimization of stem cellbased autologous therapy for aged patients.
