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关键词： 光暴露   心力衰竭   神经递质   5-羟色胺   心肌细胞损伤   核因子E2相关因子2  

摘要： 背景:心力衰竭发生发展与神经内分泌系统的异常激活密切相关.研究表明光暴露能够降低大鼠大脑中的多巴胺水平,进一步增强下丘脑室旁核内多巴胺能神经元的活动,从而促进促肾上腺皮质激素释放因子的释放.现并无直接证据证实光暴露会诱发心力衰竭. 目的:探究光暴露对心力衰竭模型大鼠神经递质释放的影响及其分子机制,并进行细胞学验证. 方法:①动物实验:将行心力衰竭造模的SD大鼠分为模型组、光暴露模型组、光暴露治疗组,将假手术大鼠分为光暴露对照组和空白组,每组各6只.8周实验结束后,使用ELISA检测光暴露对心衰大鼠血清神经递质、激素水平的影响,苏木精-伊红染色观察心脏病理变化;Western Blot检测核因子E2相关因子2/血红素氧化酶1/磷酸酰胺腺嘌呤二核苷酸醌氧化还原酶1信号通路的调节作用.②细胞实验:将小鼠心肌细胞(HL-1细胞)分为空白组、5-羟色胺高剂量对照组(5-羟色胺500 mg/mL)、脂多糖低剂量组(脂多糖1 μg/mL)、脂多糖+5-羟色胺高剂量组(5-羟色胺500 mg/mL+脂多糖1 μg/mL)、ML385组(脂多糖1 μg/mL+5-羟色胺500 mg/mL+核因子E2相关因子2抑制剂ML385为2.5 μg/mL)、白藜芦醇组(脂多糖1 μg/mL+5-羟色胺500 mg/mL+核因子E2相关因子2激动剂白藜芦醇30 μg/mL),干预36 h,考察各干预条件对于细胞增殖的影响,利用Western Blot方法,验证5-羟色胺对HL-1细胞核因子E2相关因子2/血红素氧化酶1/磷酸酰胺腺嘌呤二核苷酸醌氧化还原酶1信号轴的影响. 结果与结论:①光暴露能提升心力衰竭模型大鼠血清中的去甲肾上腺素和5-羟色胺水平,加剧心脏损伤;光暴露模型组及模型组心肌组织病理均呈现了明显的损伤,细胞出现了肿胀、核皱缩、空泡等现象;光暴露治疗组大鼠心肌细胞的损伤得到了明显的缓解;光暴露对照组的血管紧张素转换酶2蛋白表达低于空白组(P<0.05)而高于模型组(P<0.05),而Mas、c-fos及血红素氧化酶1表达与空白组相比虽有所下调,但差异无显著性意义(P>0.05).在光暴露模型组中,血管紧张素转换酶2、Mas、核因子 E2 相关因子2及血红素氧化酶1蛋白表达均较空白组显著下调(P<0.05).与光暴露模型组相比,光暴露治疗组中核因子E2相关因子2/血红素氧化酶1/磷酸酰胺腺嘌呤二核苷酸醌氧化还原酶1信号通路相关蛋白表达均明显上调(P<0.05).②细胞实验显示5-羟色胺增加了脂多糖所致的心肌细胞损伤,且该损伤效应与核因子E2相关因子2/血红素氧化酶1/磷酸酰胺腺嘌呤二核苷酸醌氧化还原酶1信号通路的抑制相关.结论:过度的光暴露可能通过调节神经递质组成,介导核因子E2相关因子2/血红素氧化酶1/磷酸酰胺腺嘌呤二核苷酸醌氧化还原酶1信号通路,加速心力衰竭的进程.

关键词： Glass  

摘要： Based on the peridynamic method， a numerical model was developed to simulate damage and crack propagation in a flat glass plate subjected to rigid-body impact，accounting for structural fracture and crack evolution. The validity of the model was verified through edge-on impact tests and impact experiments on square glass plates. On this basis，the effects of impact angle and impact velocity of a rigid sphere on the damage severity， crack morphology evolution，and crack propagation mechanisms of the glaas plate were systematically investigated. The results show that the impact angle plays a critical role in governing crack types and propagation paths. At a low impact angle (15°)，tangential momentum dominates the failure process， leading to the formation of spaUation bands and fan-shaped cracks along the impact trajectory. At intermediate impact angles (30°-45°)， the combined effects of tangential and normal momentum result in a mixed crack pattern， evolving from fan-shaped cracks to a combination of radial cracks and localized perforation. At high impact angles (60°-90° )，the failure procees is dominated by normal momentum，and radial cracks prevail，accompanied by the formation of circumferential cracks and branched crack networks. Impact velocity has a pronounced influence on damage evolution ： at low velocities，radial cracks are predominant，whereas increasing velocity promotes the development of circumferential cracks and the formation of complex radial-circumferential crack networks. Overall，higher impact velocities lead to larger maximum impact forces and more severe damage，with the number of damaged material points increasing approximately linearly with the initial impact velocity. © 2026 Chinese Vibration Engineering Society. All rights reserved.

关键词： Numerical methods  

摘要： Bending stiffness is a critical parameter that reflects the performance of a bridge， thus accurate identification of bridge bending is of great significance. Bridge influence lines can be used to identify the bridge bending stiifnes. The key is to select an appropriate bending 巳^^^巳巳 deterioration model for simulating the variation of and an effective optimization algorithm for estimating the parameters of the stiifnes model. This paper proposes a novel method for identification of bridge bending stiffness using influence lines and Bayesian optimization. The relationship between the bending and influence lines was established. Furthermore，an improved Gaussian peak function was introduced to simulate bending stiffness degradation. The feasibility and accuracy of the proposed method were verified by both numerical simulations and laboratory experiments. © 2026 Chinese Vibration Engineering Society. All rights reserved.

关键词： Subways  

摘要： The building foundation elastic pad has become one of the critical vibration control measures for sensitive structures near subway lines. However，its vibration isolation mechanism and the influence of design parameters remain unclear. This paper employs the scaled model dynamic experimental method to systematically investigate the vibration isolation performance of building foundation elastic pad. First， based on vibration isolation theory， the parameters afecting the vibration isolation effect of elastic pad beneath building foundation were derived and analyzed. Then， a scaled model experiment for the " building-elastic pad " isolation system was designed， using actual environmental vibrations from subway-adjacent areas as the excitation source to obtain vibration responses of the building model under various experimental conditions. FinaUy，by comparing test data in the time domain，frequency domain，and acceleration levels，the vibration isolation effect of the elastic pad and the influence law of key factors were studied. The results show that the elastic pad can effectively reduce the subway-induced vibration response of building structure. Pad thickness， elastic modulus，and working compreesive strees are the key factors aafecting its isolation performance. Backfill materials around the building foundation are detrimental to the vibration isolation effect of the elastic pad， and a certain vibration isolation design margin should be considered accordingly. The side pad of the building foundation plays a crucial role in subway vibration control，and both the base pad and side pad should be used in combination in practical engineering. By scale model vibration experimental method， the vibration isolation mechanism， efectivenes， and main parameter influence law of the building foundation elastic pad are deeply revealed，providing theoretical and experimental basis for vibration isolation engineering applications of buildings along subway lines. © 2026 Chinese Vibration E

摘要： 在当今竞争激烈的学术环境中,发表高质量的研究成果只是第一步.更重要的是,如何让您的研究被更多人看到并产生影响力.提高您所发表文章的使用率和读者数量对于提升您的研究知名度至关重要.要做到这一点,作者需要在文章撰写时,确保所有的研究内容都能在谷歌和其他搜索引擎的搜索结果中被看到并获得较高的排名.搜索引擎优化(SEO)是保持研究成果长期使用的关键因素之一.作者可以通过以下技巧在文章层面优化搜索结果方面发挥关键作用.

摘要： (满分150分;时间120分钟) 第一部分 听力(共两节,满分30分) 第一节(共5小题;每小题1.5分,满分7.5分) 听下面5段对话.每段对话后有一个小题,从题中所给的A、B、C三个选项中选出最佳选项.听完每段对话后,你都有10秒钟的时间来回答有关小题和阅读下一小题.每段对话读两遍.

摘要： (满分150分;时间120分钟) 第一部分 听力(共两节,满分30分) 第一节(共5小题;每小题1.5分,满分7.5分) 听下面5段对话.每段对话后有一个小题,从题中所给的A、B、C三个选项中选出最佳选项.听完每段对话后,你都有10秒钟的时间来回答有关小题和阅读下一小题.每段对话读两遍.

摘要： (满分150分;时间120分钟) 第一部分 听力(共两节,满分30分) 第一节(共5小题;每小题1.5分,满分7.5分) 听下面5段对话.每段对话后有一个小题,从题中所给的A、B、C三个选项中选出最佳选项.听完每段对话后,你都有10秒钟的时间来回答有关小题和阅读下一小题.每段对话读两遍.

摘要： 随着建筑行业规模不断扩大与市场竞争日趋激烈,工程成本控制已成为影响企业经济效益与项目成败的重要因素。建筑工程成本受多方面因素综合作用,包括设计方案的科学性、材料价格的波动、人工费用的变化、施工组织管理水平以及外部环境的不确定性等。本文围绕上述关键影响因素,系统分析其作用机理,并从设计优化、材料管控、劳动力配置、施工组织以及信息跟踪等方面提出针对性的成本管理路径,旨在为实现建筑工程经济效益最大化提供理论依据与实践参考。

关键词： 霉菌毒素吸附剂   营养素   生长   肉鸡   改善作用  

摘要： 本试验旨在研究日粮中添加吸附剂对肉鸡生长性能与健康的影响、对黄曲霉毒素B1(AFB1)的脱毒效果，以及补充维生素等营养素对脱毒效果的影响。选取288羽1日龄爱拔益加肉鸡，随机分为6组，每组8个重复。A组为对照组饲喂基础日粮，B、C、D、E、F组分别在基础日粮中添加0.5 g/kg吸附剂、0.5 g/kg吸附剂+0.2 g/kg营养素、150 μg/kg AFB1、150 μg/kg AFB1+0.5 g/kg吸附剂、150 μg/kg AFB1+0.5 g/kg吸附剂+0.2 g/kg营养素。试验期42 d。结果表明：A、B、C组间肉鸡生长性能、器官指数、血清生化指标及肝脏抗氧化指标均无显著差异（P > 0.05）。与A组相比，D组肉鸡21日龄体重及1～21日龄平均日采食量显著降低（P < 0.05），21日龄和42日龄血清AST活性显著升高（P < 0.05），21日龄肝脏GSH-Px活性显著降低（P < 0.05），肝脏油红O染色面积显著增加（P < 0.05）。与D组相比，E组可显著降低21日龄和42日龄血清AST活性（P < 0.05），并显著减少肝脏油红O染色面积（P < 0.05）；F组显著降低42日龄血清AST活性（P < 0.05），显著提高21日龄肝脏GSH-Px活性（P < 0.05）。综上，基础日粮中添加吸附剂对肉鸡生长和健康无不良影响，且能有效缓解AFB1引起的肝脏损伤和生长抑制；在吸附剂基础上额外补充营养素可进一步改善部分肝脏功能指标，但对生长性能等指标提升作用不明显。