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基于定向进化的雷公藤三萜C-29位羧化酶催化机制研究

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药学学报 2024年第6期59卷 1883-1893页

作者：刘攀婷张逸风刘远高杰马林吴晓毅胡雅婷苏平袁仕君张夏楠高伟首都医科大学中医药学院北京100069 道地药材品质保障与资源持续利用全国重点实验室中国中医科学院中药资源中心北京100700

雷公藤红素和雷公藤内酯甲是中药雷公藤的主要三萜活性成分,具有抗肿瘤、抗炎及免疫抑制等药理活性,是雷公藤相关中药制剂发挥临床疗效的物质基础。通过解析活性成分生源途径,优化基因元件并利用“细胞工厂”异源获取将是未来“低成本... 详细信息

雷公藤红素和雷公藤内酯甲是中药雷公藤的主要三萜活性成分,具有抗肿瘤、抗炎及免疫抑制等药理活性,是雷公藤相关中药制剂发挥临床疗效的物质基础。通过解析活性成分生源途径,优化基因元件并利用“细胞工厂”异源获取将是未来“低成本、高效率”获得雷公藤中三萜活性成分的有效途径。CYP712Ks是参与雷公藤木栓烷型和齐墩果烷型三萜骨架修饰的第一个细胞色素P450酶,发挥C-29位羧基化功能,可催化木栓酮生成美登木酸,催化β-香树素生成3-表卡通酸。本研究以四条多功能TwCYP712K1/2/3/5为研究对象,利用酿酒酵母体内功能表征,明确其催化功能及底物选择偏好性;通过同源建模和分子对接,明确蛋白与底物结合空间结构,进而对蛋白活性口袋内差异氨基酸进行互相突变,阐明决定催化功能和底物结构选择的关键氨基酸。本研究共构建了63个突变体元件,解析了影响TwCYP712Ks羧基化功能的氨基酸位点,特别是揭示了影响TwCYP712K2对齐墩果烷型和木栓烷型三萜底物选择性的关键氨基酸,TwCYP712K2F127I与TwCYP712K2A227T突变体将导致产物比例发生逆转。本研究以同源蛋白比对及相互突变的方式对TwCYP712Ks四条蛋白进行半理性设计,阐明多个决定蛋白催化功能的氨基酸位点,获得系列活性提升或改变的突变体,为雷公藤三萜活性成分的生物合成提供丰富的催化元件,并初步解析了C-29位羧基化机制。

关键词：雷公藤 CYP712K 定点突变美登木酸 3-表卡通酸

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UPLC-MS/MS法测定降血压类保健食品中13种二氢吡啶类钙拮抗剂

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分析测试学报 2024年第7期43卷 987-994页

作者：李林益张高勤冯星桥温毓秀李健刘玫杨瑞琴中国人民公安大学侦查学院北京100038 山西省公安厅刑事科学技术研究所山西晋中030601

建立了超高效液相色谱-串联质谱(UPLC-MS/MS)同时检测降血压类保健食品中非法添加13种二氢吡啶类钙拮抗剂的方法。片剂、功能茶样品用甲醇-水(4∶1)溶液超声提取,口服液样品用甲醇超声提取,采用Waters ACQUITY UPLC BEH C_(18)色谱柱(2.... 详细信息

建立了超高效液相色谱-串联质谱(UPLC-MS/MS)同时检测降血压类保健食品中非法添加13种二氢吡啶类钙拮抗剂的方法。片剂、功能茶样品用甲醇-水(4∶1)溶液超声提取,口服液样品用甲醇超声提取,采用Waters ACQUITY UPLC BEH C_(18)色谱柱(2.1 mm×100 mm,1.7μm)分离,以2 mmol/L甲酸铵-0.1%甲酸水溶液和乙腈为流动相梯度洗脱,采用电喷雾离子源(ESI)正离子模式,多反应监测(MRM)模式进行检测。结果显示,13种分析物在对应质量浓度范围内线性关系良好,相关系数均不低于0.998 0,平均回收率为85.1%~119%,日内相对标准偏差(RSD)为0.37%~5.6%,日间RSD为1.6%~13%。各组分在片剂、功能茶、口服液3种基质中的检出限分别为0.1~2μg/kg、0.1~5μg/kg、0.1~1.7μg/L。采用该法对46个市售样品进行检测,有2个阳性样品分别检出硝苯地平(178.1μg/kg)与马尼地平(260.2μg/kg)。该方法操作简单、灵敏度高、精密度好,适用于保健食品中非法添加二氢吡啶类钙拮抗剂的筛查与定量分析。

关键词：降血压类保健食品二氢吡啶类钙拮抗剂 UPLC-MS/MS 非法添加

The practically renewable and highly efficient electrocatalysts derived from a newly-designed Mo_(8)Pt polyoxometalate compound

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Science China Chemistry 2023年第2期66卷 492-499页

作者： Di yin Yun-Dong Cao yi feng Guang-Gang gao Hong Liu lin-lin Fan Zhen-Hui Kang School of Materials Science and Engineering University of JinanJinan250022China Institute of Functional Nano and Soft Materials(FUNSOM) Jiangsu Key Laboratory for Carbon-based Functional Materials and DevicesSoochow UniversitySuzhou215123China Macao Institute of Materials Science and Engineering(MIMSE) MUST-SUDA Joint Research Center for Advanced Functional MaterialsMacao University of Science and TechnologyTaipaMacao999078China

Platinum(Pt)catalysts are the most practical electrocatalysts;however,their low abundance and high cost severely limit their large-scale *** recovery is a key issue to be resolved before the use of Pt-based electrocatalysts can be broadly ***,the newly designed polyoxometalate[Pt^(II)(NH_(3))_(4)]_(2)[Mo_(8)O26](Mo_(8)Pt)acts as an ideal recycling medium for renewable and highly effective Pt *** from Mo_(8)Pt,by a facile reduction reaction,the formed Pt/Mo_(2)C/Mo_(2)N@C-N electrocatalyst shows superior electrocatalytic activity as compared to commercial Pt/C(20%)under both acidic and alkaline ***,the reaction of Pt/Mo_(2)C/Mo_(2)N@C-N in H_(2)O_(2)solution can regenerate Mo_(8)Pt for Pt *** is also demonstrated that the Pt electrocatalyst can be used for at least five rounds of recycling and regeneration,showing its efficiency and stability as well as its *** work highlights a recycling medium strategy to the new generation of renewable Pt-based catalysts.

关键词： platinum polyoxometalate electrocatalyst recycling-medium renewability

Agglomeration behavior of alumina inclusions and calcium aluminate inclusions on molten nickel-based superalloy surface

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Journal of Iron and Steel Research(International) 2023年第11期30卷 2318-2327页

作者： Rui-zhi gao lin-zhu Wang Chao-yi Chen Shu-feng Yang Xiang Li yin Zhang School of Materials and Metallurgy Guizhou UniversityGuiyang550025GuizhouChina School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China Department of Materials and Metallurgy Engineering Guizhou Institute of TechnologyGuiyang550003GuizhouChina

Understanding the interactive forces of inclusions on the surface of molten nickel-based superalloys and finding methods to disperse these inclusions help improve performance and service *** aggregation behavior of aluminum oxide(Al_(2)O_(3))and calcium aluminate inclusions with different sizes and spacings on the surface of molten nickel-based superalloys was observed in-situ using a high-temperature confocal laser scan *** attractive force acted on Al2O3 inclusions with radii of 3.5-6μm was found ranging from 6.2×10-18 to 3.6×10-15 N,and that of CaO·2Al2O3(CA2)inclusions with radii of 3-5.5μm ranging from 3.5×10-19 to 8.3×10-15 *** capillary force acted on inclusions on the surface of nickel-based superalloy was calculated based on the Kralchevsky-Paunov model and investigated as a function of inclusion size,spacing,and *** calculated results were in the same trend as the experimental *** capillary force acted on inclusions was also affected by their contact angle,the density,surface energy,and oxygen content of the molten *** decreased with increasing alloy density and decreasing contact angle between inclusion with ***,the attractive force acted on Al2O3 inclusions was smaller on the surface of molten nickel-based superalloy than that of molten *** the oxygen content in the molten nickel-based alloy could increase its surface energy,and the attractive force acted on the inclusions would *** the oxygen content in the molten nickel-based alloy decreased from 0.05 to 0.0001 wt.%,the capillary force acted on the Al2O3 inclusions decreased from 1.7×10-18 to 3.6×10-19 N,reduced by 79%(1.4×10-18 N).

关键词： Inclusion Nickel-based superalloy Capillary force Alumina Calcium aluminate

Nondestructive technique for identifying nuclides using neutron resonance transmission analysis at CSNS Back-n

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Nuclear Science and Techniques 2024年第1期35卷 178-187页

作者： Sheng-Da Tang Yong-Hao Chen Jing-Yu Tang Rui-Rui Fan Qiang Li Gong Li Dong Liu Zheng-Yao Jin Xing-Zhu Cui Tian-Xiang Chen yi-Wei Yang Rong Liu Han yi Yang Li Zhen Yang Qi An Hao-Fan Bai Jiang-Bo Bai Jie Bao Ping Cao Qi-Ping Chen Zhen Chen Zeng-Qi Cui An-Chuan Fan Chang-Qing feng Fan-Zhen feng Ke-Qing gao Min-Hao Gu Chang-Cai Han Zi-Jie Han Guo-Zhu He Yong-Cheng He Yang Hong yi-Wei Hu Han-Xiong Huang Wei-Hua Jia Hao-yu Jiang Wei Jiang Zhi-jie Jiang ling Kang Bo Li Chao Li Jia-Wen Li Xiao Li Jie Liu Shu-Bin Liu Guang-Yuan Luan Chang-Jun Ning Bin-Bin Qi Jie Ren Zhi-Zhou Ren Xi-Chao Ruan Zhao-Hui Song Kang Sun Zhi-Xin Tan Li-Jiao Wang Peng-Cheng Wang Zhao-Hui Wang Zhong-Wei Wen Xiao-Guang Wu Xuan Wu Li-Kun Xie Yong-Ji Yu Guo-Hui Zhang lin-Hao Zhang Mo-Han Zhang Qi-Wei Zhang Xian-Peng Zhang Yu-Liang Zhang Yue Zhang Zhi-Yong Zhang Mao-Yuan Zhao Lu-Ping Zhou Zhi-Hao Zhou Ke-Jun Zhu Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China Institute of High-Energy Physics Chinese Academy of Sciences(CAS)Beijing 100049China Spallation Neutron Source Science Center Dongguan 523803China School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230026China State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China State Key Laboratory of Particle Detection and Electronics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China USTC Archaeometry Laboratory University of Science and Technology of ChinaHefei 230026China Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang 621900China Department of Modern Physics University of Science and Technology of ChinaHefei 230026China State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China Key Laboratory of Nuclear Data China Institute of Atomic EnergyBeijing 102413China Northwest Institute of Nuclear Technology Xi’an 710024China University of Chinese Academy of Sciences Beijing 100049China

Nondestructive and noninvasive neutron assays are essential applications of neutron *** resonance transmission analysis(NRTA)is a powerful nondestructive method for investigating the elemental composition of an *** back-streaming neutron line(Back-n)is a newly built time-of-flight facility at the China Spallation Neutron Source(CSNS)that provides neutrons in the eV to 300 MeV range.A feasibility study of the NRTA method for nuclide identification was conducted at the CSNS Back-n via two test *** results demonstrate that it is feasible to identify different elements and isotopes in samples using the NRTA method at *** study reveals its potential future applications.

关键词： CSNS White neutron beam NRTA Nuclide identification Nondestructive method

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辽东山区红松人工林生态系统多功能性研究

西北林学院学报 2024年第2期39卷 51-59,209页

作者：杨圆圆刘金义战金伟卜鹏图肖尧高慧淋冯健辽宁省林业科学研究院辽宁沈阳110032 辽宁白石砬子森林生态系统国家定位观测研究站辽宁丹东118201 国有清原满族自治县大边沟林场辽宁抚顺113305 国有清原满族自治县大孤家林场辽宁抚顺113305 沈阳农业大学林学院辽宁沈阳110161

以辽东山区不同林龄红松人工林为对象,设置30块不同立地条件样地,调查分析红松生长、林下灌草和土壤养分水分等特性,选取乔木层碳储量、土壤养分维持、土壤水源涵养、生物多样性维持、生产力和木材生产等生态功能,利用平均值法量化其多... 详细信息

以辽东山区不同林龄红松人工林为对象,设置30块不同立地条件样地,调查分析红松生长、林下灌草和土壤养分水分等特性,选取乔木层碳储量、土壤养分维持、土壤水源涵养、生物多样性维持、生产力和木材生产等生态功能,利用平均值法量化其多功能性,探讨不同功能间的协同-权衡关系和驱动多功能性的主要因子,以期为红松人工林的持续健康经营提供支撑。结果表明,辽东山区红松人工林多功能性指数在0.38~0.78,随林龄增加而显著上升。不同功能间以权衡关系占据主导地位;10龄红松人工林乔木层碳储量、生产力和木材生产三者之间权衡度为0、10、34龄和43龄土壤养分维持功能与其他功能间权衡度最高。红松活枝下高、优势木高、坡度、坡位、土壤C∶N、C∶K和N∶K是影响红松人工林多功能性指数的主要环境因子。为实现红松人工林的森林多功能性,在造林时立地条件尽量选择小坡度、阴坡和低坡位,营林过程中应避免高强度修枝,注重林下生物多样性保育,加强修枝剩余物和凋落物管理,必要时进行林地施肥,促进林分因子、地形因子和土壤养分间的协调发展,推动红松人工林持续健康经营。

关键词：红松人工林森林多功能性平均值法协同-权衡

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降混剂对二氧化碳在稠油中的溶解度和最小混相压力的影响

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油田化学 2024年第1期41卷 93-100页

作者：于田田刘廷峰冯海顺廖毅盖平原林吉生高海杰杨子浩中国石化胜利油田分公司石油工程技术研究院山东东营257001 山东省稠油开采重点实验室山东东营257001 中国石油大学(北京)非常规油气科学技术研究院北京102249

针对CO_(2)驱油过程中,稠油体系与CO_(2)难混相,最小混相压力高于地层破裂压力的问题,对CO_(2)与原油的混合体系进行了分子模拟,考察了降混剂种类和加量、温度、压力的影响。由径向分布函数得到混相过程中CO_(2)分子及沥青质分子的聚集... 详细信息

针对CO_(2)驱油过程中,稠油体系与CO_(2)难混相,最小混相压力高于地层破裂压力的问题,对CO_(2)与原油的混合体系进行了分子模拟,考察了降混剂种类和加量、温度、压力的影响。由径向分布函数得到混相过程中CO_(2)分子及沥青质分子的聚集程度,进而明确各类分子的分散状态,分析其作用机理。在此基础上,开展高温高压PVT相态实验,测定CO_(2)与原油混合体系中添加不同降混剂后的体积膨胀系数和CO_(2)溶解度,对分子模拟结果进行验证。最后,对柠檬酸三甲酯、苯甲醇、苯甲酸乙酯3种降混剂进行优选,得到最优复配配方,并通过细管实验评价其降混性能。分子模拟结果表明,柠檬酸三甲酯的降混效果最为显著,可有效增大CO_(2)分子间的聚集程度,降低沥青质分子间的聚集程度;在高压(6.90 MPa)低温(308.15 K)的条件下,降混剂更能发挥其作用。PVT相态实验结果表明,0.23%柠檬酸三甲酯的增溶与增膨作用最佳,与分子模拟结果一致。降混剂最优复配配方为80%柠檬酸三甲酯+20%苯甲酸乙酯。在原油-CO_(2)体系中加入0.23%复配降混剂,最小混相压力降幅为21.47%,CO_(2)溶解度和原油采收率提高。降混剂含有亲油的烃类基团和亲CO_(2)的酯基,不仅能与原油体系中的极性分子结合,拆散各沥青分子的聚集体,同时在双亲性能作用下,能吸附在原油与CO_(2)的界面上,降低原油与CO_(2)的界面张力,进而降低最小混相压力。

关键词： CO_(2)驱稠油溶解度最小混相压力降混剂分子模拟

Review on Offloading of Vehicle Edge Computing

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Journal of Artificial Intelligence and Technology 2022年第4期2卷 132-143页

作者： Mingwei Wang Hualing yi feng Jiang ling lin and Min gao Chongqing Business Vocational College ChongqingChina Chongqing Chang’an Automobile Co. LtdChongqingChina Chongqing University ChongqingChina

Vehicle Edge Computing(VEC)is a new technology that can extend computing and storage functions to the edge of the Internet of Things *** limited computing power and delay-sensitive mobile applications on the Internet of Vehicles(IoV),it is important to offload computing tasks to the end of the VEC ***,high mobility data security and privacy resource management and the randomness of IoV brought about new problems to the offloading of *** this end,this study focuses on the offloading of computing tasks in *** survey principal offloading schemes and methods in the VEC field and classify the current offloading of computing tasks into different *** also discuss the prospect of *** survey could give a reference for researchers to find and understand the essential characteristics of VEC,which helps choose the optimal solutions for the offloading of computing tasks in VEC.

关键词： computing offloading internet of vehicle vehicle edge computing

自研(1+1)分布式侧面泵浦光纤实现20 kW激光输出

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光学学报 2024年第9期44卷 318-321页

作者：李峰云刘念张春代江云黄值河曹涧秋高聪陈艺黄伶俐楚秋慧张昊宇陶汝茂史仪赵龙彪林宏奂王建军王泽锋景峰中国工程物理研究院激光聚变研究中心四川绵阳621900 国防科技大学前沿交叉学科学院湖南长沙410073 国防科技大学南湖之光实验室湖南长沙410073 南京理工大学电子工程与光电技术学院江苏南京210094

基于改进的化学气相沉积预制棒制备技术和多光纤并束拉丝光纤拉制工艺,成功制备了(1+1)型分布式侧面泵浦光纤,其中信号纤芯/包层尺寸为60/300μm,泵浦纤芯尺寸为310μm。通过主振荡功率放大结构搭建反向泵浦放大系统,以1018 nm激光器为... 详细信息

基于改进的化学气相沉积预制棒制备技术和多光纤并束拉丝光纤拉制工艺,成功制备了(1+1)型分布式侧面泵浦光纤,其中信号纤芯/包层尺寸为60/300μm,泵浦纤芯尺寸为310μm。通过主振荡功率放大结构搭建反向泵浦放大系统,以1018 nm激光器为级联泵浦源,该光纤激光器最终实现了20.13 kW的最高功率输出,经过拟合后的斜率效率为82.3%,由泵浦纤反向端输出的残余泵浦比例的最大值为6%,信号光受激拉曼散射抑制比达到37.65 dB。在测试中,光纤所有部位均表现出优异的热负载性能,这是首次通过(1+1)型分布式侧面泵浦方式实现了20 kW的单根光纤输出功率。

关键词：光纤光学高功率光纤激光器分布式侧面泵浦残余泵浦受激拉曼散射

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