NOX4 exacerbates Parkinson's disease pathology by promoting neuronal ferroptosis and neuroinflammation

Parkinson's disease is primarily caused by the loss of dopaminergic neurons in the substantia nigra compacta.Ferroptosis,a novel form of regulated cell death characterized by iron accumulation and lipid peroxidation,plays a vital role in the death of dopaminergic neurons.However,the molecular mechanisms underlying ferroptosis in dopaminergic neurons have not yet been completely elucidated.NADPH oxidase 4 is related to oxidative stress,however,whether it regulates dopaminergic neuronal ferroptosis remains unknown.The aim of this study was to determine whether NADPH oxidase 4 is involved in dopaminergic neuronal ferroptosis,and if so,by what mechanism.We found that the transcriptional regulator activating transcription factor 3 increased NADPH oxidase 4 expression in dopaminergic neurons and astrocytes in an 1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine-induced Parkinson's disease model.NADPH oxidase 4 inhibition improved the behavioral impairments observed in the Parkinson's disease model animals and reduced the death of dopaminergic neurons.Moreover,NADPH oxidase 4 inhibition reduced lipid peroxidation and iron accumulation in the substantia nigra of the Parkinson's disease model animals.Mechanistically,we found that NADPH oxidase 4 interacted with activated protein kinase Cαto prevent ferroptosis of dopaminergic neurons.Furthermore,by lowering the astrocytic lipocalin-2 expression,NADPH oxidase 4 inhibition reduced 1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine-induced neuroinflammation.These findings demonstrate that NADPH oxidase 4 promotes ferroptosis of dopaminergic neurons and neuroinflammation,which contribute to dopaminergic neuron death,suggesting that NADPH oxidase 4 is a possible therapeutic target for Parkinson's disease.

多模态模型嵌入知识生成的逻辑机理与路径选择

基于海量数据与强大算法的多模态模型依赖复杂的结构框架,在嵌入知识生成的过程中展现出跨域数据处理能力和持续输出创新数据等核心特征。高度智能化的知识数据整理、自适应多场景的知识表达与动态协同聚合的知识共享等,推进知识生成逻辑从既有信息理解向全新知识产出的转变。然而,多模态模型逐渐暴露出缺乏合法可靠的知识数据源、透明可释的生成过程以及高质量内容输出等诸多问题。亟待通过搭建价值对齐的生成模型、提升可控生成的技术水平、完善人类反馈提示策略、构筑基于规则的管控体系等约束其更好地支撑知识生成,加速创新驱动新质生产力发展的进程。

毛蕊花糖苷对腺嘌呤所致不育症大鼠的影响

目的 探讨毛蕊花糖苷对腺嘌呤诱导的不育症大鼠的作用及其机制。方法 大鼠随机分为空白组、模型组、阳性对照组(100 mg/kg复方玄驹胶囊)和毛蕊花糖苷低、高剂量组(50、100 mg/kg)。除空白组外,其余各组每天灌胃150 mg/kg腺嘌呤,连续14 d,建立不育症大鼠模型。造模结束后,各组灌胃给予相应剂量药物,连续给药28 d。观察各组大鼠一般活动情况,计算脏器(肝脏、肾脏、睾丸、附睾)指数,于显微镜下观察精子情况,HE染色观察大鼠肝脏、肾脏及睾丸组织病理形态,并进行精子发生评估(Johnsen评分法),ELISA法检测血清T、LH、FSH、GnRH水平,RT-qPCR和Western blot法检测大鼠睾丸组织mTOR、LC3B、ULK1 mRNA和蛋白表达。结果 与空白组比较,模型组大鼠肾脏指数升高(P<0.05),精子计数、精子活动率及精子指数降低(P<0.05),血清T、GnRH水平降低(P<0.05),LH、FSH水平升高(P<0.05),肾脏和睾丸组织病理损伤明显,睾丸组织mTOR mRNA和蛋白表达升高(P<0.05),LC3B、ULK1 mRNA和蛋白表达降低(P<0.05),p-mTOR蛋白表达降低(P<0.05);与模型组比较,毛蕊花糖苷高剂量组肾脏指数降低(P<0.05),精子计数、精子活动率升高(P<0.05),血清T水平升高(P<0.05),LH、FSH水平降低(P<0.05),肾脏和睾丸组织病理损伤有不同程度改善,睾丸组织mTOR mRNA和蛋白表达降低(P<0.05),LC3B、ULK1 mRNA和蛋白表达升高(P<0.05),p-mTOR蛋白表达升高(P<0.05),且毛蕊花糖苷高剂量作用与阳性对照药复方玄驹胶囊相当。结论 毛蕊花糖苷能有效提高不育症大鼠的精子质量,改善性激素紊乱、生殖功能及肾脏、睾丸组织病理性损伤,其作用机制可能与增强正性调控自噬,调节下丘脑-垂体-睾丸轴紊乱有关。

基于技术专利视角的创新链与产业链融合发展研究

创新链与产业链融合发展能优化双链协同性和开放性,增强比较优势和创新链韧性,使得创新更容易发生,产业链分工更加紧密。双链融合内在驱动力主要得益于创新基础能力的强化、产业内创新与产业间创新的广泛开展。从创新基础能力、产业内创新网络、产业间创新网络3个维度设计评价指标体系,利用产业数据和技术专利数据对中国及部分OECD国家的产业链与创新链融合情况进行对比分析。研究发现:总体而言,我国创新链产业链融合指数水平近30年来实现大幅提升,目前与日本相当,高于韩国及OECD平均水平,但落后于美国和德国,在一些关键核心技术领域与全球领先水平相比仍有差距,双链融合发展存在不容忽视的风险。为此,需聚焦关键核心技术创新重点领域,不断完善高端要素体系,夯实双链融合基础能力,促进产业间融合创新和地区间互补创新。

中国新旧动能技术转换的特征事实与政策建议——基于关键使能技术专利的指数分析

根据各类专利分布对TFP加权,设计技术创新动能指数和新旧动能技术转换指数,利用2001—2015年中国专利数据库发明专利申请数据,对各地区在技术创新层面的新旧动能转换情况进行刻画。研究发现,关键使能技术对中国经济发展的推动作用要强于传统动能技术,新旧动能技术转换在2012年后逐渐趋缓;长三角地区是关键使能技术创新的中心地区,也是中国新旧动能技术转换的主要动力源;东部、中部地区保持相似的转换水平,西部地区转换指数落后于其他地区,呈现差距扩大趋势,东北地区转换指数较高,但与人均GDP增长相关性较弱。我国应完善技术创新新型大国体制,让市场激励与政府“制度之手”“帮助之手”形成合力,集中资源攻克关键使能技术中的“卡脖子”技术;围绕关键使能技术,加强产学研平台的建设,实现关键核心领域的自主可控;充分依托现有产业结构有区别地引导技术创新,形成全国范围内优势互补的创新格局。

AUTOSAR可运行实体-任务自动映射方法研究

下一代汽车电子标准AUTOSAR定义汽车应用程序设计过程包括系统级设计和ECU级设计。系统级设计以软件构件为单位来设计应用,其中软件构件包含一组可运行实体。ECU级设计主要将可运行实体代码组织为嵌入式实时操作系统任务。因此,在将分配到ECU的软件构件集转换为实时系统任务集的过程中,需要有经验的嵌入式开发工程师进行可运行实体-任务的映射配置,以保证系统的实时性。鉴于可运行实体-任务的映射配置工作具有配置需求量大、复杂度高等特点,文中设计了一种可运行实体-任务自动映射方法。该方法综合考虑了可运行实体的触发关系、周期需求、数据共享等因素,对提高汽车软件开发效率具有非常重要的实用价值。最后,将该方法应用于AUTOSAR标准的汽车电子巡航控制系统实例中。实验结果显示,所提方法在抖动时间、阻塞时间、调度频繁度和数据通信量4个方面都具有良好的表现。

基于网络药理学探究黄诺玛苷对非酒精性脂肪肝的降脂作用

目的利用网络药理学探索黄诺玛苷抗非酒精性脂肪肝病(non-alcoholic fatty liver disease,NAFLD)的作用靶点和信号通路,研究黄诺玛苷治疗NAFLD的作用机理。方法(1)在Swiss Target Prediction数据库中检索黄诺玛苷活性靶点,DisGeNET数据库中搜索疾病靶点,通过化合物靶点与疾病靶点作Venn分析得到黄诺玛苷调节NAFLD脂代谢的预测靶点。借助Biso Genet软件构建蛋白-蛋白相互作用(protein-protein interaction,PPI)网络图,利用Metascape数据库对核心靶点进行GO功能富集与KEGG通路富集分析,用Cytoscape软件绘制"靶点-通路"网络图。(2)采用db/db小鼠模型进行体内实验验证,30只雄性db/db小鼠按随机数字表法分为3组:db/m组(正常)、db/db模型组、db/db+黄诺玛苷组(50 mg/kg)。给药12周后处死,取小鼠肝脏,检测肝脏TG、GSH、GSSG含量,HE和油红O染色观察肝脏病理学变化,qRT-PCR和Western blot检测小鼠肝脏脂代谢的关键mRNA及蛋白的表达水平。(3)HepG2细胞在游离脂肪酸(free fatty acids,FFAs,油酸∶棕榈酸=2∶1)干预成模后,分为正常组、FFAs处理组(500μmol/L)、FFAs+黄诺玛苷低中高浓度组(25、50、100μmol/L),作用24 h。油红O染色检测HepG2细胞内TG的含量。qRT-PCR和Western blot检测HepG2细胞脂代谢的关键mRNA及蛋白的表达水平。结果(1)通过Venn分析,得到黄诺玛苷对接NAFLD的29个核心靶点,主要包括过氧化物酶体增殖物激活受体(PPARγ)、血管内皮生长因子(VEGF)和丝裂原活化蛋白激酶14(MAPK14)等。GO功能富集了6个分子功能、20个生物过程、5个细胞组分。KEGG富集的关键信号通路有40条,主要包括AMPK脂代谢通路、胰岛素抵抗(IR)通路、细胞凋亡通路等。(2)动物实验结果表明,黄诺玛苷能降低db/db模型组TG水平(P<0.05),提高GSH/GSSG比例(P<0.05)。HE和油红O染色显示黄诺玛苷可逆转肝细胞的肿大,减少肝细胞内的脂滴浸润。qRT-PCR结果表明黄诺玛苷可以降低脂质合成基因ACC1、SCD1、FASN mRNA的表达(P<0.05),增强β-氧化基因ACOX-1、CPT1αmRNA的表达(P<0.05)。Western blot结果显示,与db/db模型组相比,db/db+黄诺玛苷组SREBP、FASN蛋白水平显著降低(P<0.05),PPARγ、PPARα蛋白水平显著升高(P<0.05)。(3)体外细胞实验表明,黄诺玛苷可以降低HepG2细胞的TG含量(P<0.05),降低脂质合成基因SREBP、SCD1、ACC1的表达,提高CPT1α、ACOX-1 mRNA水平(P<0.05)。在蛋白水平,黄诺玛苷可以显著降低SREBP、FASN的表达(P<0.05)。结论黄诺玛苷可能通过调节PPARγ/SREBP/FASN信号通路改善氧化应激,增强脂肪酸β-氧化并减少脂质合成,对NAFLD发挥治疗作用。

两色金鸡菊提取物对胰岛素抵抗小鼠肠道菌群的影响

目的探索两色金鸡菊提取物对胰岛素抵抗小鼠肠道菌群的影响。方法采用高脂饲料诱导胰岛素抵抗小鼠模型,造模成功后给予不同剂量两色金鸡菊提取物以及二甲双胍干预,采用实时荧光定量PCR检测肠道P.distasonis、B.ovatus、Sutterella菌的变化。结果凝胶成像分析仪观察结果表明B.ovatus、P.distasonis、Sutterella菌目的片段条带单一,引物特异性好。B.ovatus、P.distasonis、Sutterella普通PCR扩增产物测序后,与GenBank数据库比对,各目的片段分别与Bacteroides ovatus ATCC 8483、Parabacteroides distasonis ATCC 8503、Parasutterellaexcrementihominis YIT 11859 Scfld40最为接近。干预8周后与正常组相比,模型组B.ovatus、P.distasonis、Sutterella含量降低,差异有统计学意义(P<0.05)。与模型组相比,两色金鸡菊提取物各剂量组和二甲双胍组B.ovatus含量升高,两色金鸡菊提取物高、中剂量组和二甲双胍组P.distasonis含量升高,二甲双胍组Sutterella含量升高,差异有统计学意义(P<0.05)。P.distasonis与空腹血糖(r=-0.327,P=0.042)水平呈负相关,B.ovatus与空腹血糖(r=-0.310,P=0.021)水平呈负相关。结论两色金鸡菊提取物可影响胰岛素抵抗小鼠肠道中的P.distasonis、B.ovatus菌是其发挥降糖作用的机制之一。

地区市场整合如何影响地区创新路径——基于技术多样化的视角

立足于畅通国内市场大循环,优化地区创新路径和提升创新能力具有重要意义。文章基于技术结构范式界定了地区创新路径的方式,考察了国内市场整合对地区创新路径的影响。采用2000—2015年中国专利数据和区域市场整合数据,实证检验了国内市场整合对中国地区技术多样化创新路径的影响。研究发现:国内市场整合程度显著提升,地区创新路径呈现技术多样化的不同形式,从相关技术多样化向不相关技术多样化的创新多样性逐步转变,国内市场整合对地区创新路径存在显著的影响,国内市场整合程度的提升更明显地激励地区实行不相关技术多样化的创新模式,促进地区创新路径向不相关技术多样化的方向收敛,主要从提升国内需求、优化要素配置和增强区域间技术关联三个渠道影响地区创新路径的变化。进一步分析发现,出口规模会有利于地区选择相关技术多样化创新,但会抑制生产率水平的提升,而国内市场整合可以缓解出口的消极作用。(因此通过整合国内市场,加快建设统一的国内市场环境,打破地方形成壁垒,是提升地区创新能力和优化创新路径,推动国家创新体系建设的重要举措。)

基于纳什均衡的AUTOSAR任务到多核ECU的映射方法

随着汽车电子应用程序对处理器性能需求的不断提高,现代汽车电子系统中的电子控制单元(ECU)已升级为多核结构。多核ECU中的AUTOSAR应用程序的设计、实现和集成将面临新的挑战。其中一个重要的挑战是在映射任务到多核ECU的同时确保系统的实时性能。且在AUTOSAR静态配置过程中,实时系统的资源限制和调度分析使问题变得更加复杂。因此,文中提出了一种基于纳什均衡的AUTOSAR任务到多核ECU的映射方法。该方法将任务优先级应用于博弈过程中,对提高任务映射过程的效率具有非常重要的实用价值。最后,将所提方法应用于AUTOSAR标准的实例中。实验结果表明,所提方法在减少各个任务中可运行实体的最坏响应时间方面具有良好的表现。

肉苁蓉苯乙醇总苷对胆汁淤积型肝病小鼠的预防保护作用

目的考察肉苁蓉苯乙醇总苷对α-萘异硫氰酸酯(α-naphthalene isothiocyanate,ANIT)诱导的小鼠胆汁淤积性肝病的预防保护作用。方法采用C57小鼠连续灌胃给予肉苁蓉苯乙醇总苷125、250、500 mg·kg^(-1)(肉苁蓉苯乙醇总苷低、中、高剂量组)和阳性药甘利欣100 mg·kg^(-1)7 d,每日给药1次,第5天给药后2 h单次灌胃给予ANIT 80 mg·kg^(-1)诱导造模,模型组小鼠等量灌胃生理盐水,其余各组小鼠继续用药干预2 d后收集小鼠血液与组织样本。检测血清中谷丙转氨酶(ALT)、谷草转氨酶(AST)、白蛋白(ALB)、碱性磷酸酶(AKP)、乳酸脱氢酶(LDH)、总胆红素(TBIL)、胆汁酸(TBA)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)和丙二醛(MDA)水平,观察肝脏组织病理学变化。结果与模型组相比,肉苁蓉苯乙醇总苷各组能够明显降低ANIT模型小鼠中ALT、AST、AKP、TBA、TBIL和MDA水平(P<0.05);肉苁蓉苯乙醇总苷中、高剂量组显著提高ALB、GSH-Px和SOD的活性(P<0.05)。结论肉苁蓉苯乙醇总苷可能通过改善细胞膜通透性和消除自由基氧化,从而发挥对ANIT所诱导的胆汁淤积性肝病小鼠的预防保护作用。

2012~2019年天津市公交站微环境空气质量改善

于2012年9月、2014年3月、2015年6月和2019年6月在天津市八里台公交站采集环境空气样品,分析该微环境中大气可吸入颗粒物(PM_(10))污染的整体改善趋势以及PM_(10)中碳组分、水溶性离子组分以及元素组分的特征和4次采样之间的差异.结果表明,4次采样的PM_(10)浓度分别为281,217,188,78μg/m^(3),呈明显下降趋势.其中水溶性离子组分和元素组分浓度逐年降低,但其占比变化不大(平均浓度占比分别为22%和39%),4次采样的二次离子SNA(即SO_(4)^(2-),NO_(3)−和NH_(4)^(+))占PM_(10)比例分别为11%,9%,9%,17%;总碳质量浓度逐年降低,碳组分在PM_(10)中所占的比例呈波动上升的趋势(从18%上升至32%,平均为25%),根据估算结果,4次采样的二次有机碳(SOC)占PM_(10)比例分别为4%,9%,9%,13%.研究显示,天津市交通微环境空气质量改善效果显著,但二次组分(SNA和SOC)在PM_(10)中占比呈上升趋势,需进一步加强二次污染的控制.

化铁丸化学成分分析及其防治乳腺增生的潜在机制预测

目的分析化铁丸处方中威灵仙和楮实子的化学成分并预测其防治乳腺增生的潜在作用机制,为后续揭示化铁丸药效物质基础及其防治乳腺增生潜在分子机制提供参考。方法利用UPLC-Orbitrap Exploris-MS技术,在正负离子模式下进行全扫描检测。通过中国知网、SciFinder、PubChem、TCMSP等数据库进行对比,分析化铁丸提取物(以80%甲醇为溶剂)的化学成分;采用网络药理学方法,通过类药性和口服生物利用度进行筛选,获得活性成分并利用SwissTargetPrediction数据库对化合物成分进行靶点预测,借助OMIM数据库获取乳腺增生相关靶点;采用String在线数据库构建蛋白质-蛋白质相互作用(PPI)网络图;通过DAVID数据库进行基因本体(GO)富集分析和京都基因和基因组百科全书(KEGG)通路分析,并采用Cytoscape3.8.0软件构建“中药-活性成分-靶点-信号通路”网络图。结果从化铁丸中初步鉴定出101个化合物,包括22个萜类成分、22个黄酮类成分、14个苯丙素类成分、10个酚类成分、9个生物碱、9个氨基酸、4个酯类成分、4个脂肪酰类成分、4个脂肪酸类成分、2个山酮类成分、1个有机酸类成分。根据类药性(DL≥0.18)和口服生物利用度(OB≥30%)筛选出24个活性成分,通过OMIM数据库检索到2003个乳腺增生相关靶点基因,取交集得到化铁丸与乳腺增生交互靶点250个,PPI网络分析得出9个核心网络蛋白包括TNF、VEGFA、PI3KCA、PI3KR1、MAPK1、EGFR、AKT1、SRC、HSP90AA1。结论网络分析结果表明,化铁丸治疗乳腺增生与蛋白质磷酸化、信号转导、蛋白质自磷酸化等生物学过程有关。化铁丸中丰富的化学成分可能通过调节MAPK、Ras等信号通路发挥防治乳腺增生的作用。

Advances in nuclear detection and readout techniques

“A Craftsman Must Sharpen His Tools to Do His Job,”said Confucius.Nuclear detection and readout techniques are the foundation of particle physics,nuclear physics,and particle astrophysics to reveal the nature of the universe.Also,they are being increasingly used in other disciplines like nuclear power generation,life sciences,environmental sciences,medical sciences,etc.The article reviews the short history,recent development,and trend of nuclear detection and readout techniques,covering Semiconductor Detector,Gaseous Detector,Scintillation Detector,Cherenkov Detector,Transition Radiation Detector,and Readout Techniques.By explaining the principle and using examples,we hope to help the interested reader underst and this research field and bring exciting information to the community.

Study on the method of precision adjustment of star sensor

Star sensors are indispensable spatial measurement sensors for high-resolution earth observation and astronomical observations, and the demand for high measurement accuracy of satellite sensors continues to increase; thus, the star sensor optical machine adjustment error cannot be ignored. The commonly used installation error correction method cannot solely meet the precision analysis requirements. In this paper, the relationship between the optical machine installation and the star sensor measurement error is analyzed, and several common adjustment error correction methods are compared. An adjustment method for optical machines is proposed to meet the requirements of very high precision star sensors. The assembly precision requirements of the investigated very high precision star sensor are analyzed considering the whole machine, and then the optical components are controlled through optical precision adjustments to satisfy the precision requirements. Finally, through the complete machine calibration, the star sensor precision adjustment for an optical machine structure is verified. This method meets the requirements of very high precision sensors and is suitable for the precision adjustment of optical machine structures, which is of practical significance to improve the precision of star sensors.

通信网络运维多维评估模型设计及应用

通信网络运行维护工作是电信运营商的一项基础性重要工作。当前,世界各运营商网络运维工作公开披露的信息相对较少,缺乏评估各运营商电信网络运维水平的有效模型。以平衡积分卡方法为基础,结合长期通信网络运维体系研究及工作实践,创新性地提出了通信网络运维多维评估模型,并应用该模型对国际大型电信运营商、创新型电信运营商、高增长型电信运营商3种不同类型的运营商进行对比分析,以期对国内运营商网络运维工作发展提供有效的评估和指引。

Application Progress of Plant Growth-promoting Bacteria in Crops

Plant growth-promoting bacteria(PGPBs)can promote plant growth and improve crop yield.They can induce plant systemic resistance to resist biotic and abiotic stresses.In recent years,with the development of green ecological agriculture,new biological fertilizers such as microbial inocula and microbial fertilizers based on PGPBs have been gradually applied in crop planting.Based on plant growth promotion and disease control,the application progress of PGPBs in crops from the aspects of growth promotion mechanism,growth promotion effect,resistance to biological and abiotic stresses were discussed,aiming to provide reference for the relevant research and application of PGPBs in crops.

A survey of public needs for digital information service in libraries and museums

Purpose:The purpose of the research is to investigate public needs for digital information service in the Chinese libraries and museums and seek ways to help these public service institutions improve their service to meet user needs.Design/methodology/approach:An online questionnaire survey was used to study the publicneeds for digital information service provided by libraries and museums.A total of 474 valid questionnaires were retrieved for analysis.Findings:The primary purpose of using the digital library and museum service was for knowledge acquisition,followed by work or class assignment and leisure and entertainment.Users need one-stop information service that provides information and service in a more integrated form and allows cross-database searching as well.Research limitations:A majority of the respondents were young and middle-aged people who often use the Internet.We would need to increase our sample size and include different groups of users such as children and retirees to make the sample more representative.Practical implications:Libraries and museums should collaborate to provide the users with one-stop digital information service.Meanwhile,the research can serve as a reference source for the future studies of digital library and museum service.Originality/value:Few studies were published on the public needs for digital library and museum service in China.This study bridges the gap and contributes to our understanding of the Chinese users’ needs for digital information service in libraries and museums.

Research progress on biological functions of lncRNAs in major vegetable crops

With the advances in genomics and bioinformatics,particularly the extensive application of high-throughput sequencing technology,a large number of non-coding RNAs(ncRNAs)have been discovered,of which long ncRNAs(lncRNAs)refer to a class of transcripts that are more than 200 nucleotides in length.Accumulating evidence demonstrates that lncRNAs play significant roles in a wide range of biological processes,including regulating plant growth and development as well as modulating biotic and abiotic stress responses.Although the study of lncRNAs has been a hotspot of biological research in recent years,the functional characteristics of plant lncRNAs are still in their initial phase and face great challenges.Here,we summarize the characteristics and screening methods of lncRNAs and highlight their biological functions in major vegetable crops,including tomato,Brassica genus crops,cucumber,pepper,carrot,radish,potato,and spinach,which are implicated in the interaction of lncRNAs and miRNAs.This review enhances the understanding of lncRNAs'roles and can guide crop improvement programs in the future.

Detection approach for unusable shared bikes enabled by reinforcement learning and PageRank algorithm

Existing research models can neither indicate the availability of shared bikes nor detect unusable ones owing to a lack of information on bike maintenance and failure.To improve awareness regarding the availability of shared bikes,we propose an innovative approach for detecting unusable shared bikes based on reinforcement learning and the PageRank algorithm.The proposed method identifies unusable shared bikes depending on the local travel data and provides a ranking of the shared bikes according to their availability levels.Given a sliding time window,the value function for the reinforcement learning model was determined by considering the cumulative number of unavailable shared bikes,the proportion of rental cancelations at the same stations,and the mean time between the cancelations.Reinforcement learning was then used to identify shared bikes with the worst availability.An availability ranking for the shared bikes below the reward threshold was performed using the PageRank algorithm.The proposed detection approach was applied to a trip dataset of a real-world bike-sharing system to illustrate the modeling process and its effectiveness.The detection results of unusable shared bikes in the absence of failure and feedback data can provide essential information to support the maintenance management decisions regarding shared bikes.