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The burden of depression,anxiety and schizophrenia among the older population in ageing and aged countries:an analysis of the Global Burden of Disease Study 2019 被引量:5
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作者 Ying Cheng Yu Fang +3 位作者 Jinxin Zheng shiyang Guan Meiti Wang Wu Hong 《General Psychiatry》 CSCD 2024年第1期83-93,共11页
Background Depression,anxiety and schizophrenia among older persons have become global public health challenges.However,the burden of these disorders in ageing and aged countries has not been analysed.Aims To investig... Background Depression,anxiety and schizophrenia among older persons have become global public health challenges.However,the burden of these disorders in ageing and aged countries has not been analysed.Aims To investigate the burden of depression,anxiety and schizophrenia among older adults in ageing and aged countries.Methods Using data from the Global Burden of Disease Study 2019,we calculated the estimated annual percentage change(EAPC)in the age-standardised incidence rates(ASiR)and age-standardised disability-adjusted life years(DALYs)rates(ASDR)for depression,anxiety and schizophrenia of older people in ageing countries(China,India,Indonesia)and aged countries(Japan,Italy,Portugal)between 1990 and 2019.Trends in incidence and DALYs were analysed by gender and age.Results In 2019,the highest incidence of depression,anxiety and schizophrenia in the older population in aged countries was in Japan(927271.3(752552.3-1125796.5),51498.2(37625.7-70487.3)and 126.0(61.0-223.2),respectively),while the highest incidence in ageing countries was in China(5797556.9(4599403.4-7133006.5),330256.1(246448.9-445987.4)and 1067.7(556.2-1775.9),respectively).DALYs for these disorders were similar,with the highest in Japan and China.From 1990 to 2019,the ASIR for depressive disorders decreased in aged countries but increased in ageing countries;the ASIR for anxiety disorders and schizophrenia declined in both ageing and aged countries.The ASDR for depressive disorders was consistent with the ASIR but not for anxiety disorders and schizophrenia.The ASIR for depressive disorders was higher in older women,while the opposite was observed in anxiety disorders and schizophrenia.Notably,the conditions of burden of depressive disorders,anxiety disorders and schizophrenia in the 65-70-year-old age group were the most burdensome.Conclusions The incidence and DALYs of these three mental disorders increased while exhibiting differences between ageing and aged countries.Raising awareness about formulating health policies for preventing and treating mental disorders in the older population is necessary to reduce the future burden posed by the ageing challenge. 展开更多
关键词 SCHIZOPHRENIA BURDEN ageing
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基于密度泛函理论研究Ag-Co团簇的结构、电子和光学性能
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作者 李维银 尚瑞咏 +1 位作者 王春勇 张永莉 《原子与分子物理学报》 CAS 北大核心 2025年第2期63-69,共7页
基于密度泛函理论研究了7个原子Ag-Co团簇结构的稳定性、电子和光学性能.研究结果表明,7个原子Ag-Co团簇的最稳定结构都是十面体结构,Co原子数量较少时,Co原子主要占据十面体的轴向位,Ag原子主要占据赤道位,随着Co原子数的增加,Co原子... 基于密度泛函理论研究了7个原子Ag-Co团簇结构的稳定性、电子和光学性能.研究结果表明,7个原子Ag-Co团簇的最稳定结构都是十面体结构,Co原子数量较少时,Co原子主要占据十面体的轴向位,Ag原子主要占据赤道位,随着Co原子数的增加,Co原子逐渐替换了赤道位上的Ag原子.当Co原子数增加时,Ag-Co团簇的垂直电离势、垂直电子亲能和最高占据轨道与最低未占据轨道之间的能隙整体上都呈现出下降趋势,表明电子稳定性降低;Ag-Co团簇的吸收光谱整体出现了红移,吸收峰的强度逐渐减弱,吸收谱的宽度变窄. 展开更多
关键词 银钴团簇 几何结构 电子性能 光学性能
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Mitigating the negative catalytic effect of CuO by FAS-17 coated Al nanopowder:Isothermal ageing of Al/CuO nanothermite at 71°C and 60%relative humidity 被引量:1
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作者 Fuwei Li Qian Wang +6 位作者 Jian Cheng Zehua Zhang Yuxuan Zhou Keer Ouyang Jianbing Xu Yinghua Ye Ruiqi Shen 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第4期156-167,共12页
The safety and reliability of weapon systems would be significantly affected by changes in the performance of energetic materials due to ambient temperature and humidity.Nanothermites have promising applications due t... The safety and reliability of weapon systems would be significantly affected by changes in the performance of energetic materials due to ambient temperature and humidity.Nanothermites have promising applications due to their excellent reactivity.Therefore it becomes extremely important to understand their aging and failure process in the environment before using them.Here,the aging and failure process of Al/CuO in 71°C/60%RH were investigated,and showed that CuO nanoparticles negatively catalyze Al nanopowders,resulting in rapid hydration.The anti-aging effect of FAS-17-coated Al nanopowder was also examined.The aging process of Al,Al/CuO,and Al@FAS-17/CuO in high humidity and heat environment were revealed by quasi-in situ SEM and TEM methods.Compared with the aging of pure Al,the Al nanopowder in the nanothermites strongly agglomerated with the CuO nanopowder and hydrated earlier.This may be caused by CuO catalyzed hydration of Al nanopowder.The energy release experiments showed that the performance of Al/CuO decreased rapidly and failed to ignite after 4 h of aging.In contrast,the Al@FAS-17/CuO thermite can achieve long-term stability of up to 60 h in the same environment by simple cladding of FAS-17.It is found that FAS-17 coated Al nanopowder can prevent both particle agglomeration and water erosion,which is an effective means to make nanothermites application in high humidity and heat environment. 展开更多
关键词 Al/CuO nanothermite FAS-17 coating aging and failure process
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Mechanism of high temperature oxidation of Inconel 625 superalloy with various solution and ageing heat treatment processes
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作者 Jiang-kun FAN Hong-ci YANG +7 位作者 Pei-zhe ZHANG Jia-yu LI Zhan-jie JING Fu-long CHEN De-gui LIU Bin TANG Hong-chao KOU Jin-shan LI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第11期3662-3676,共15页
The high-temperature oxidation behaviour of the Inconel 625 alloy at 950℃ was investigated after different ageing treatments.The effect of heat treatment on the oxidation behaviour of the alloy was analysed by charac... The high-temperature oxidation behaviour of the Inconel 625 alloy at 950℃ was investigated after different ageing treatments.The effect of heat treatment on the oxidation behaviour of the alloy was analysed by characterizing the structure and elemental distribution before and after oxidation.The results reveal that the two ageing treatments at 650℃ for 500 h and at 750℃ for 400 h both reduced the oxidation mass gain.After oxidation at 950℃,an outer Cr_(2)O_(3) layer and inner Al_(2)O_(3) are identified as the main oxidation products.Moreover,Nb_(2)O_(5) andδ(Ni_(3)Nb)phases precipitated after oxidation.The ageing treatments cause the rapid generation of a dense Cr_(2)O_(3) layer on the surface,which prevents the diffusion of oxygen into the matrix,reduce the Al_(2)O_(3) inward growth depth,and improve the oxidation resistance of the alloy. 展开更多
关键词 Inconel 625 alloy ageing treatment oxidation behaviour oxidation film KINETICS
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High density dislocations enhance creep ageing response and mechanical properties in 2195 alloy sheet
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作者 WEI Shuo MA Pei-pei +3 位作者 CHEN Long-hui YANG Jian-shi ZHAN Li-hua LIU Chun-hui 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2194-2209,共16页
The creep strain of conventionally treated 2195 alloy is very low,increasing the difficulty of manufacturing Al-Cu-Li alloy sheet parts by creep age forming.Therefore,finding a solution to improve the creep formabilit... The creep strain of conventionally treated 2195 alloy is very low,increasing the difficulty of manufacturing Al-Cu-Li alloy sheet parts by creep age forming.Therefore,finding a solution to improve the creep formability of Al-Cu-Li alloy is vital.A thorough comparison of the effects of cryo-deformation and ambient temperature large pre-deformation(LPD)on the creep ageing response in the 2195 alloy sheet at 160℃with different stresses has been made.The evolution of dislocations and precipitates during creep ageing of LPD alloys are revealed by X-ray diffraction and transmission electron microscopy.High-quality 2195 alloy sheet largely pre-deformed by 80%without edge-cracking is obtained by cryo-rolling at liquid nitrogen temperature,while severe edge-cracking occurs during room temperature rolling.The creep formability and strength of the 2195 alloy are both enhanced by introducing pre-existing dislocations with a density over 1.4×10^(15)m^(−2).At 160℃and 150 MPa,creep strain and creep-aged strength generally increases by 4−6 times and 30−50 MPa in the LPD sample,respectively,compared to conventional T3 alloy counterpart.The elongation of creep-aged LPD sample is low but remains relevant for application.The high-density dislocations,though existing in the form of dislocation tangles,promote the formation of refined T1 precipitates with a uniform dispersion. 展开更多
关键词 creep ageing Al-Cu-Li alloy high dislocation density cryogenic rolling dislocation strengthening
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Influence of Non-Natural Ageing Temperature on the Microstructural Characteristics and Mechanical Properties of Cast Aluminum 6063 Alloy
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作者 Oluwole Oladele Ayodele Adedeke +1 位作者 Olajesu Olanrewaju Samuel Olusunle 《Journal of Minerals and Materials Characterization and Engineering》 2024年第2期91-99,共9页
This research considered the effect of non-natural aging on the microstructural characteristics and mechanical properties of as-cast aluminum 6063 alloys. The samples were developed through a sand casting process and ... This research considered the effect of non-natural aging on the microstructural characteristics and mechanical properties of as-cast aluminum 6063 alloys. The samples were developed through a sand casting process and machined into tensile and impact test samples before carrying out solution heat treatment at 550?C (0.83 T<sub>m</sub>) on two parts of the samples while retaining one part as the control. The two parts were further divided into sets denoted A and B and were aged at 180?C (0.27 T<sub>m</sub>) and 160?C (0.24 T<sub>m</sub>), respectively, for 12 hours. The results showed that sample A has the optimal yield strength and ultimate tensile strength of 192 and 206 MPa, respectively. Likewise, the sample gave the highest impact strength value of about 9.63 J/mm<sup>2</sup>. The observed results were supported by the optical micrograph, which revealed that the sample has evenly dispersed precipitates in its microstructure. This is deemed responsible for the observed increase in strength of the sample. 展开更多
关键词 Aluminum Alloy Non-Natural ageing Mechanical Properties Microstructural Features
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Dendritic spine degeneration:a primary mechanism in the aging process
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作者 Gonzalo Flores Leonardo Aguilar-Hernández +3 位作者 Fernado García-Dolores Humberto Nicolini Andrea Judith Vázquez-Hernández Hiram Tendilla-Beltrán 《Neural Regeneration Research》 SCIE CAS 2025年第6期1696-1698,共3页
Recent reports suggest that aging is not solely a physiological process in living beings;instead, it should be considered a pathological process or disease(Amorim et al., 2022). Consequently, this process involves a w... Recent reports suggest that aging is not solely a physiological process in living beings;instead, it should be considered a pathological process or disease(Amorim et al., 2022). Consequently, this process involves a wide range of factors, spanning from genetic to environmental factors, and even includes the gut microbiome(GM)(Mayer et al., 2022). All these processes coincide at some point in the inflammatory process, oxidative stress, and apoptosis, at different degrees in various organs and systems that constitute a living organism(Mayer et al., 2022;AguilarHernández et al., 2023). 展开更多
关键词 agING PROCESS STRESS
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Regeneration mechanisms and therapeutic strategies for neuromuscular junctions in aging and diseases
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作者 Masashi Fujitani Abu Md Mamun Tarif Yoshinori Otani 《Neural Regeneration Research》 SCIE CAS 2025年第1期193-194,共2页
The neuromuscular junction(NMJ)is an essential synaptic structure composed of motor neurons,skeletal muscles,and glial cells that orchestrate the critical process of muscle contraction(Li et al.,2018).The typical NMJ ... The neuromuscular junction(NMJ)is an essential synaptic structure composed of motor neurons,skeletal muscles,and glial cells that orchestrate the critical process of muscle contraction(Li et al.,2018).The typical NMJ structure is classically described as having a“pretzel-like”shape in mice(Figure 1),whereas human NMJs have a smaller,fragmented structure throughout adulthood.Degenerated NMJs exhibit smaller or fragmented endplates,partial denervation,reduced numbers of synaptic vesicles,abnormal presynaptic mitochondria,and dysfunctional perisynaptic Schwann cells(Alhindi et al.,2022). 展开更多
关键词 agING STRUCTURE FIGURE
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Decline and fall of aging astrocytes:the human perspective
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作者 Alexei Verkhratsky Alexey Semyanov 《Neural Regeneration Research》 SCIE CAS 2025年第6期1713-1714,共2页
“Last scene of all that ends this strange,eventful history,is second childishness and mere oblivion.I am sans teeth,sans eyes,sans taste,sans everything.”William Shakespeare‘As You Like It'Act 2,Sc.7,l.139Aging... “Last scene of all that ends this strange,eventful history,is second childishness and mere oblivion.I am sans teeth,sans eyes,sans taste,sans everything.”William Shakespeare‘As You Like It'Act 2,Sc.7,l.139Aging of the human brain is characterized by a progressive decline of its functional capacity;this decline however varies widely,and cognitive longevity differs substantially between individuals. 展开更多
关键词 agING teeth PROGRESSIVE
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Neuronal regulated cell death in aging-related neurodegenerative diseases:key pathways and therapeutic potentials
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作者 Run Song Shiyi Yin +1 位作者 Jiannan Wu Junqiang Yan 《Neural Regeneration Research》 SCIE CAS 2025年第8期2245-2263,共19页
Regulated cell death(such as apoptosis,necroptosis,pyroptosis,autophagy,cuproptosis,ferroptosis,disulfidptosis)involves complex signaling pathways and molecular effectors,and has been proven to be an important regulat... Regulated cell death(such as apoptosis,necroptosis,pyroptosis,autophagy,cuproptosis,ferroptosis,disulfidptosis)involves complex signaling pathways and molecular effectors,and has been proven to be an important regulatory mechanism for regulating neuronal aging and death.However,excessive activation of regulated cell death may lead to the progression of aging-related diseases.This review summarizes recent advances in the understanding of seven forms of regulated cell death in age-related diseases.Notably,the newly identified ferroptosis and cuproptosis have been implicated in the risk of cognitive impairment and neurodegenerative diseases.These forms of cell death exacerbate disease progression by promoting inflammation,oxidative stress,and pathological protein aggregation.The review also provides an overview of key signaling pathways and crosstalk mechanisms among these regulated cell death forms,with a focus on ferroptosis,cuproptosis,and disulfidptosis.For instance,FDX1 directly induces cuproptosis by regulating copper ion valency and dihydrolipoamide S-acetyltransferase aggregation,while copper mediates glutathione peroxidase 4 degradation,enhancing ferroptosis sensitivity.Additionally,inhibiting the Xc-transport system to prevent ferroptosis can increase disulfide formation and shift the NADP^(+)/NADPH ratio,transitioning ferroptosis to disulfidptosis.These insights help to uncover the potential connections among these novel regulated cell death forms and differentiate them from traditional regulated cell death mechanisms.In conclusion,identifying key targets and their crosstalk points among various regulated cell death pathways may aid in developing specific biomarkers to reverse the aging clock and treat age-related neurodegenerative conditions. 展开更多
关键词 apoptosis autophagy cuproptosis disulfidptosis ferroptosis NECROPTOSIS neurodegenerative disease neurological aging diseases PANoptosis PYROPTOSIS
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Decoding molecular mechanisms:brain aging and Alzheimer's disease
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作者 Mahnoor Hayat Rafay Ali Syed +9 位作者 Hammad Qaiser Mohammad Uzair Khalid Al-Regaiey Roaa Khallaf Lubna Abdullah Mohammed Albassam Imdad Kaleem Xueyi Wang Ran Wang Mehwish SBhatti Shahid Bashir 《Neural Regeneration Research》 SCIE CAS 2025年第8期2279-2299,共21页
The complex morphological,anatomical,physiological,and chemical mechanisms within the aging brain have been the hot topic of research for centuries.The aging process alters the brain structure that affects functions a... The complex morphological,anatomical,physiological,and chemical mechanisms within the aging brain have been the hot topic of research for centuries.The aging process alters the brain structure that affects functions and cognitions,but the worsening of such processes contributes to the pathogenesis of neurodegenerative disorders,such as Alzheimer's disease.Beyond these observable,mild morphological shifts,significant functional modifications in neurotransmission and neuronal activity critically influence the aging brain.Understanding these changes is important for maintaining cognitive health,especially given the increasing prevalence of age-related conditions that affect cognition.This review aims to explore the age-induced changes in brain plasticity and molecular processes,differentiating normal aging from the pathogenesis of Alzheimer's disease,thereby providing insights into predicting the risk of dementia,particularly Alzheimer's disease. 展开更多
关键词 Alzheimer’s disease brain aging cognitive health DEMENTIA molecular mechanisms neuronal activity NEUROPLASTICITY NEUROTRANSMISSION
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Unraveling brain aging through the lens of oral microbiota
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作者 Qinchao Hu Si Wang +2 位作者 Weiqi Zhang Jing Qu Guang-Hui Liu 《Neural Regeneration Research》 SCIE CAS 2025年第7期1930-1943,共14页
The oral cavity is a complex physiological community encompassing a wide range of microorganisms.Dysbiosis of oral microbiota can lead to various oral infectious diseases,such as periodontitis and tooth decay,and even... The oral cavity is a complex physiological community encompassing a wide range of microorganisms.Dysbiosis of oral microbiota can lead to various oral infectious diseases,such as periodontitis and tooth decay,and even affect systemic health,including brain aging and neurodegenerative diseases.Recent studies have highlighted how oral microbes might be involved in brain aging and neurodegeneration,indicating potential avenues for intervention strategies.In this review,we summarize clinical evidence demonstrating a link between oral microbes/oral infectious diseases and brain aging/neurodegenerative diseases,and dissect potential mechanisms by which oral microbes contribute to brain aging and neurodegeneration.We also highlight advances in therapeutic development grounded in the realm of oral microbes,with the goal of advancing brain health and promoting healthy aging. 展开更多
关键词 Alzheimer's disease brain aging multiple sclerosis NEURODEGENERATION neurodegenerative diseases oral microbiota Parkinson's disease PERIODONTITIS BACTERIA Porphyromonas gingivalis
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Gut microbiota-astrocyte axis: new insights into age-related cognitive decline
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作者 Lan Zhang Jingge Wei +5 位作者 Xilei Liu Dai Li Xiaoqi Pang Fanglian Chen Hailong Cao Ping Lei 《Neural Regeneration Research》 SCIE CAS 2025年第4期990-1008,共19页
With the rapidly aging human population,age-related cognitive decline and dementia are becoming increasingly prevalent worldwide.Aging is considered the main risk factor for cognitive decline and acts through alterati... With the rapidly aging human population,age-related cognitive decline and dementia are becoming increasingly prevalent worldwide.Aging is considered the main risk factor for cognitive decline and acts through alterations in the composition of the gut microbiota,microbial metabolites,and the functions of astrocytes.The microbiota–gut–brain axis has been the focus of multiple studies and is closely associated with cognitive function.This article provides a comprehensive review of the specific changes that occur in the composition of the gut microbiota and microbial metabolites in older individuals and discusses how the aging of astrocytes and reactive astrocytosis are closely related to age-related cognitive decline and neurodegenerative diseases.This article also summarizes the gut microbiota components that affect astrocyte function,mainly through the vagus nerve,immune responses,circadian rhythms,and microbial metabolites.Finally,this article summarizes the mechanism by which the gut microbiota–astrocyte axis plays a role in Alzheimer’s and Parkinson’s diseases.Our findings have revealed the critical role of the microbiota–astrocyte axis in age-related cognitive decline,aiding in a deeper understanding of potential gut microbiome-based adjuvant therapy strategies for this condition. 展开更多
关键词 age aging Alzheimer’s disease ASTROCYTES cognitive decline dementia gut microbiota gut–brain axis microbial metabolites NEUROINFLAMMATION Parkinson’s disease
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Age-related driving mechanisms of retinal diseases and neuroprotection by transcription factor EB-targeted therapy
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作者 Samuel Abokyi Dennis Yan-yin Tse 《Neural Regeneration Research》 SCIE CAS 2025年第2期366-377,共12页
Retinal aging has been recognized as a significant risk factor for various retinal disorders,including diabetic retinopathy,age-related macular degeneration,and glaucoma,following a growing understanding of the molecu... Retinal aging has been recognized as a significant risk factor for various retinal disorders,including diabetic retinopathy,age-related macular degeneration,and glaucoma,following a growing understanding of the molecular underpinnings of their development.This comprehensive review explores the mechanisms of retinal aging and investigates potential neuroprotective approaches,focusing on the activation of transcription factor EB.Recent meta-analyses have demonstrated promising outcomes of transcription factor EB-targeted strategies,such as exercise,calorie restriction,rapamycin,and metformin,in patients and animal models of these common retinal diseases.The review critically assesses the role of transcription factor EB in retinal biology during aging,its neuroprotective effects,and its therapeutic potential for retinal disorders.The impact of transcription factor EB on retinal aging is cell-specific,influencing metabolic reprogramming and energy homeostasis in retinal neurons through the regulation of mitochondrial quality control and nutrient-sensing pathways.In vascular endothelial cells,transcription factor EB controls important processes,including endothelial cell proliferation,endothelial tube formation,and nitric oxide levels,thereby influencing the inner blood-retinal barrier,angiogenesis,and retinal microvasculature.Additionally,transcription factor EB affects vascular smooth muscle cells,inhibiting vascular calcification and atherogenesis.In retinal pigment epithelial cells,transcription factor EB modulates functions such as autophagy,lysosomal dynamics,and clearance of the aging pigment lipofuscin,thereby promoting photoreceptor survival and regulating vascular endothelial growth factor A expression involved in neovascularization.These cell-specific functions of transcription factor EB significantly impact retinal aging mechanisms encompassing proteostasis,neuronal synapse plasticity,energy metabolism,microvasculature,and inflammation,ultimately offering protection against retinal aging and diseases.The review emphasizes transcription factor EB as a potential therapeutic target for retinal diseases.Therefore,it is imperative to obtain well-controlled direct experimental evidence to confirm the efficacy of transcription factor EB modulation in retinal diseases while minimizing its risk of adverse effects. 展开更多
关键词 age-related macular degeneration anti-aging interventions autophagy calorie restriction diabetic retinopathy exercise glaucoma NEUROMODULATION PHagOCYTOSIS photoreceptor outer segment degradation retinal aging transcription factor EB
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Ni-Ag双原子团簇催化甲烷干法重整反应的理论研究
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作者 刘佳 慕红梅 +3 位作者 张明明 李文雅 李东东 张建辉 《原子与分子物理学报》 CAS 北大核心 2025年第3期13-20,共8页
甲烷干重整制合成气是将温室气体转换为合成气的有效途径,兼具环境效益和经济效益.本文采用密度泛函理论方法对Ni-Ag双原子团簇催化甲烷干重整反应的体系进行理论研究,对势能面上各驻点进行了全几何参数优化,通过频率分析确认了过渡态,... 甲烷干重整制合成气是将温室气体转换为合成气的有效途径,兼具环境效益和经济效益.本文采用密度泛函理论方法对Ni-Ag双原子团簇催化甲烷干重整反应的体系进行理论研究,对势能面上各驻点进行了全几何参数优化,通过频率分析确认了过渡态,并通过内禀反应坐标方法进行了验证,得出各基元反应的能量最低路径.研究结果对于理解在Ni上引入第二种金属Ag形成双原子团簇催化甲烷干法重整的理论研究有一定的意义,并为下一步实验研究提供理论基础. 展开更多
关键词 甲烷干重整 Ni-ag双原子团簇 密度泛函理论 活化能
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TEM STUDY ON MICROSTRUCTURAL DEVELOPMENT OF SINGLE-AGEING 7055 ALUMINUM ALLOYS 被引量:1
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作者 沈凯 尹志民 王涛 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2007年第3期265-269,共5页
Mierostruetural development of a commercial 7055 (Al-Zn-Mg-Cu)alloy is studied by transmission electron mieroseope(TEM) during the process of single-ageing for up to 48 h. It is observed that Guinier-Preston (GP... Mierostruetural development of a commercial 7055 (Al-Zn-Mg-Cu)alloy is studied by transmission electron mieroseope(TEM) during the process of single-ageing for up to 48 h. It is observed that Guinier-Preston (GP) zones are formed on { 111} planes when the sample is aged for a short time and grows up gradually with increase of ageing time. η' phase is formsed after ageing for 4 h at 120℃, having the orientation relationship with the matrix as[0 0 0 1]η'//[1 1^- 1]Al and (1 0 1^- 1)η'//(1 1 0)Al.η phase starts to occur after 24 h ageing and has an orientation relationship with matrix as [1^- 1 0 0]η//[1 1 0]Al and (0 0 0 1)η// (1 1 1)Al. Since the density of both η' phase and η phase particles is much lower than that of GP zone on aged alloy, GP zones are important to control the properties of the alloy. 展开更多
关键词 7055 aluminum alloys ageing TEM
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Effect of ageing time on corrosion behavior of Mg-10Gd-4.8Y-0.6Zr extruded-alloy 被引量:1
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作者 李慧中 刘洪挺 +3 位作者 郭菲菲 王海军 梁霄鹏 刘楚明 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第7期1498-1505,共8页
The corrosion behaviors of Mg-10Gd-4.8Y-0.6Zr extruded-alloys with various ageing time were investigated by immersion test and electrochemical measurements.The results show that the corrosion rate of the experimental ... The corrosion behaviors of Mg-10Gd-4.8Y-0.6Zr extruded-alloys with various ageing time were investigated by immersion test and electrochemical measurements.The results show that the corrosion rate of the experimental alloy decreases with the increase of ageing time from 0 to 108 h.The corrosion resistance of the experimental alloy was found to increase with the increase of the size of the precipitate phases.The open circuit potential of the experimental alloy increases with the increase of the ageing time.The potentiodynamic polarization curves show that the cathodic over-potential increases with the increase of ageing time,leading to a decrease in the current density of anodic current plateau with the increase of ageing time. 展开更多
关键词 Mg-10Gd-4.8Y-0.6Zr alloy corrosion behavior ageing time
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A Kinetic Model of Dielectric Ageing
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作者 丁洪志 赵如宝 +1 位作者 邢修三 朱鹤孙 《Journal of Beijing Institute of Technology》 EI CAS 1996年第1期55-62,共8页
A kinetic model of dielectric ageing is presented. The central finding of this investigation is that there is a power-law relationship between the local electric field concentration and the rate of defect-tip initiate... A kinetic model of dielectric ageing is presented. The central finding of this investigation is that there is a power-law relationship between the local electric field concentration and the rate of defect-tip initiated conducting crack growth. By applying such a power-law conducting crack growth rate expression to the evaluation of the life of solid dielectrics, the empirical classical ageing law of insulation materials can be derived theoretically as a lobical result. All the results are universal and agree with the experimental data of oxide films. 展开更多
关键词 dielectric ageing KINETICS conducting crack electric field intensity factor
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Fractal Studies on Dielectric Ageing
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作者 丁洪志 赵如宝 +1 位作者 邢修三 朱鹤孙 《Journal of Beijing Institute of Technology》 EI CAS 1996年第2期176+171-176,共7页
A stochastic model of conducting crack propagation is presented to provide a conceptual framework dedicated to the study of the formation of fractal structure of dielectric ageing patterns as a result of a competition... A stochastic model of conducting crack propagation is presented to provide a conceptual framework dedicated to the study of the formation of fractal structure of dielectric ageing patterns as a result of a competition between random fluctuation growth and applied electric strength enhanced deterministic growth. The necessary and sufficient conditions resulting in fractal behaviour in dielectric ageing are found. 展开更多
关键词 dielectric ageing fractal behaviour conductiong crack Fokker-Planck equation scale invariance
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固化单宁纤维素基气凝胶吸附还原Ag(I)行为研究
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作者 陈颖 林昱灵 +4 位作者 吕源财 刘以凡 林春香 叶晓霞 刘明华 《中国环境科学》 EI CAS CSCD 北大核心 2024年第4期2083-2092,共10页
以纤维素为原料,在NaOH/尿素/H_(2)O溶解体系中通过交联作用将橡椀单宁固化在纤维素基体上,制得固化橡椀单宁纤维素基气凝胶(VTCA).通过SEM-EDS、FT-IR、XRD等对VTCA进行表征,并研究其对水溶液中Ag(I)的吸附行为.结果表明,VTCA具有明显... 以纤维素为原料,在NaOH/尿素/H_(2)O溶解体系中通过交联作用将橡椀单宁固化在纤维素基体上,制得固化橡椀单宁纤维素基气凝胶(VTCA).通过SEM-EDS、FT-IR、XRD等对VTCA进行表征,并研究其对水溶液中Ag(I)的吸附行为.结果表明,VTCA具有明显的三维网格多孔结构,孔隙率达到97.95%,在较宽的pH范围内(1~8)对Ag(I)均保持较高的吸附效率(>75%).吸附过程符合拟二级动力学模型和Langmuir吸附等温线模型,温度升高有利于吸附,最高理论吸附量为147.2mg/g.吸附还原研究机理表明,VTCA主要通过静电吸引和螯合作用将Ag(I)吸附到其表面,并通过单宁结构上的酚羟基将其原位还原为Ag^(0),证明VTCA具有良好的吸附还原性能,能够实现对水体中Ag(I)的回收. 展开更多
关键词 吸附 还原 纤维素基气凝胶 橡椀单宁 ag(I)
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