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改进QuEChERS方法结合超高效液相色谱-串联质谱法快速测定藏茶中88种农药残留

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分析测试学报 2024年第4期43卷 590-599页

作者：严晓贤仝凯旋朱浙辉谢瑜杰吴兴强常巧英石志红范春林陈辉中国检验检疫科学研究院北京100176 河北大学化学与材料科学学院河北保定071002 西藏自治区产品质量监督检验所西藏拉萨850000

建立了藏茶中88种农药残留的改进QuEChERS/超高效液相色谱-串联质谱(QuEChERS/UPLC-MS/MS)检测方法。藏茶样品以1%乙酸乙腈提取和2 g NaCl盐析处理,经交联聚乙烯基吡咯烷酮(PVPP)、十八烷基键合硅胶(C18)、石墨化炭黑(GCB)净化后,以0.01... 详细信息

建立了藏茶中88种农药残留的改进QuEChERS/超高效液相色谱-串联质谱(QuEChERS/UPLC-MS/MS)检测方法。藏茶样品以1%乙酸乙腈提取和2 g NaCl盐析处理,经交联聚乙烯基吡咯烷酮(PVPP)、十八烷基键合硅胶(C18)、石墨化炭黑(GCB)净化后,以0.01%甲酸水溶液(含2 mmol/L甲酸铵)和0.01%甲酸甲醇为流动相,采用ACQUITY UPLC BEH C18(50 mm×2.1 mm,1.7µm)色谱柱在15 min内实现分离。在电喷雾正离子模式下,采用多反应监测(MRM)模式检测,基质匹配标准曲线外标法定量。结果表明,藏茶中88种农药在相应质量浓度范围内线性良好(相关系数r≥0.9990),检出限(LOD)和定量下限(LOQ)分别为0.15~3µg/kg和0.5~10µg/kg。在1、2、10倍LOQ 3个加标水平下,平均回收率分别为73.2%~108%、73.2~109%、72.5%~110%,相对标准偏差(RSD)均不大于12%。将该方法应用于12批实际样品检测,所有样品均检出农药,其中有4批次样品中吡虫啉超限量值。该方法灵敏度高、简便快捷,能够满足藏茶中88种农药的快速检测要求。

关键词：改进QuEChERS 藏茶超高效液相色谱-质谱法农药残留

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Single-Nucleotide Resolution Mapping of the Gossypium raimondii Transcriptome Reveals a New Mechanism for Alternative Splicing of Introns

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Molecular Plant 2014年第5期7卷 829-840页

作者： Qin li Guanghui Xiao yu-xian zhu State Key Laboratory of Protein and Plant Gene Research College of Life Sciences Peking University Beijing 100871 China National Center for Plant Gene Research (Beijing) Beijing 100101 China

Alternative splicing （AS） is a vital genetic mechanism that enhances the diversity of eukaryotic transcriptomes. Here, we generated 8.3 Gb high-quality RNA-sequencing data from cotton （Gossypium raimondii） and performed a systematic, comparative analysis of AS events. We mapped 85% of the RNA-sequencing data onto the reference genome and identified 154 368 splice junctions with 16 437 as events in 10197 genes. I ntron retention constituted the majority （40%） of all AS events in G. raimondii. Comparison across 11 eukaryote species showed that intron retention is the most common AS type in higher plants. Although transposable elements （TEs） were found in only 2.9% of all G. raimondii introns, they are present in 43% of the retained introns, suggesting that TE-insertion may be an important mechanism for intron retention during AS. The majority of the TE insertions are concentrated 0-40 nt upstream of the 3＇-splice site, substantially altering the distribution of branch points from preferred positions and reducing the efficiency of intron splicing by decreasing RNA secondary structure flexibility. Our data suggest that TE-insertion-induced changes in branch point-site distribution are important for intron retention-type AS. Our findings may help explain the vast differences in intron-retention frequencies between vertebrates and higher plants.

关键词： cotton RNA-seq alternative splicing transposable element intron retention.

Dynamics in a Discrete-time Predator-prey System with Allee Effect

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Acta Mathematicae Applicatae Sinica 2013年第1期29卷 143-164页

作者： xian-wei Chen xiang-ling Fu zhu-jun Jing Department of Mathematics Hunan Normal University School of Mathematics and Computational Science Hunan University of Science and Technology Academy of Mathematics and Systems Science Chinese Academy of Sciences

In this paper, dynamics of the discrete-time predator-prey system with Allee effect are investigated in detail. Conditions of the existence for flip bifurcation and Hopf bifurcation are derived by using the center manifold theorem and bifurcation theory, and then further illustrated by numerical simulations. Chaos in the sense of Marotto is proved by both analytical and numerical methods. Numerical simulations included bifurcation diagrams, Lyapunov exponents, phase portraits, fractal dimensions display new and rich dynamical behavior. More specifically, apart from stable dynamics, this paper presents the finding of chaos in the sense of Marotto together with a host of interesting phenomena connected to it. The analytic results and numerical simulations demostrates that the Allee constant plays a very important role for dynamical behavior. The dynamical behavior can move from complex instable states to stable states as the Allee constant increases （within a limited value）. Combining the existing results in the current literature with the new results reported in this paper, a more complete understanding of the discrete-time predator-prey with Allee effect is given.

关键词： Predator-prey System Allee effect flip bifurcation Hopf bifurcation Marotto's chaos transientchaos invariant circle periodic window

Complex Dynamics in a Discrete-time Predator-prey System without Allee Effect

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Acta Mathematicae Applicatae Sinica 2013年第2期29卷 355-376页

作者： xian-wei CHEN xiang-ling FU zhu-jun JING School of Mathematics and Computational Science Hunan University of Science and Technology Department of Mathematics Hunan Normal University Academy of Mathematics and Systems Science Chinese Academy of Sciences

In this paper, complex dynamics of the discrete-time predator-prey system without Allee effect are investigated in detail. Conditions of the existence for flip bifurcation and Hopf bifurcation are derived by using center manifold theorem and bifurcation theory and checked up by numerical simulations. Chaos, in the sense of Marotto, is also proved by both analytical and numerical methods. Numerical simulations included bifurcation diagrams, Lyapunov exponents, phase portraits, fractal dimensions display new and richer dynamics behaviors. More specifically, this paper presents the finding of period-one orbit, period-three orbits, and chaos in the sense of Marotto, complete period-doubling bifurcation and invariant circle leading to chaos with a great abundance period-windows, simultaneous occurrance of two different routes （invariant circle and inverse period- doubling bifurcation, and period-doubling bifurcation and inverse period-doubling bifurcation） to chaos for a given bifurcation parameter, period doubling bifurcation with period-three orbits to chaos, suddenly appearing or disappearing chaos, different kind of interior crisis, nice chaotic attractors, coexisting （2,3,4） chaotic sets, non-attracting chaotic set, and so on, in the discrete-time predator-prey system. Combining the existing results in the current literature with the new results reported in this paper, a more complete understanding is given of the discrete-time predator-prey systems with Allee effect and without Allee effect.

关键词： predator-prey system flip bifurcation Hopf bifurcation Marotto's chaos transient chaos

Simultaneous Enhancement of Toughness and Strength of Stretched iPP Film via Tiny Amount of β-Nucleating Agent under “Shear-free” Melt-extrusion

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Chinese Journal of Polymer Science 2021年第11期39卷 1481-1488页

作者： Zhong-zhu liu Guo-Qiang Zheng Hong-Hui Shi chun-Tai liu li-wei Mi Qian li xian-Hu liu College of Material and Chemical Engineering Henan Key Laboratory of Functional Salt MaterialsCenter for Advanced Materials ResearchZhongyuan University of TechnologyZhengzhou 450007China National Center for International Joint Research of Micro-Nano Molding Technology School of Mechanics&Safety EngineeringZhengzhou UniversityZhengzhou 450002China College of Materials Science and Engineering National Engineering Research Center for Advanced Polymer Processing TechnologyZhengzhou UniversityZhengzhou 450001China

Herein,isotactic polypropylene films with smallβ-nucleating agent content were fabricated via a melt-extrusion-stretched technology with intended"shear-free"in barrel and *** with neat films,the tensile strength,elongation at break and strain energy density at break of i PP film with 0.05 wt%β-nucleating agent are significantly improved by 13.8%,39.6%and 90.6%,respectively,indicating the simultaneously enhanced toughness and ***,theβ-crystal content gradually increases with increasingβ-NA content,while the relative total daughter content ofα-andβ-crystal exhibits opposite ***,nucleation and crystal growth induced by variousβ-NA contents are *** work proves an efficient strategy to enhance mechanical properties of isotactic polypropylene film via controlling elongation flow and addition of appropriateβ-NA content.

关键词： Melt-extrusion Isotactic polypropylene β-Nucleating agent Crystallization Mechanical properties

Corrigendum to"Crystal structure of RNA helicase from Saint Louis encephalitis virus and discovery of its inhibitors"[Genes Dis 10(2023)389-392]

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Genes & Diseases 2024年第3期11卷 484-484页

作者： De-Ping Wang Fang-ying Jiang xian-Yan Zeng yu-Jie liu Rong Zhao Mei-yue Wang Jing luo Chen Chen Yong zhu Ji-Min Cao Key Laboratory of Cellular Physiology at Shanxi Medical University Ministry of Educationand the Department of PhysiologyShanxi Medical UniversityTaiyuanShanxi 030001China College of life Sciences Chongqing Medical UniversityChongqing 400016China Department of Biochemistry and Molecular Biology School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China Department of Rheumatology The Second Hospital of Shanxi Medical UniversityTaiyuanShanxi 030001China

We're very sorry for missing a funding program in funding ***,we would like to add this program:The Natural Science Foundation of Tianjin(China)(No.21JCQNJCO1890)from Tianjin Science and Technology in the first *** au... 详细信息

关键词： section. Tianjin funding

超声辅助提取长孢洛德酵母菌中2种绿原酸的工艺优化及其抗氧化活性研究

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粮食与油脂 2024年第5期37卷 64-68页

作者：唐洁张国栋朱平川冯钰涵朱文虎樊宪伟亚热带农业生物资源保护与利用国家重点实验室广西南宁530004

以长孢洛德酵母P212菌株发酵液为原料,采用超声辅助法提取绿原酸和新绿原酸。以2种绿原酸和总绿原酸含量为指标,在单因素试验的基础上通过正交试验优化提取工艺,并评价其抗氧化活性。结果表明:最佳提取工艺条件为超声功率90 W、提取温... 详细信息

以长孢洛德酵母P212菌株发酵液为原料,采用超声辅助法提取绿原酸和新绿原酸。以2种绿原酸和总绿原酸含量为指标,在单因素试验的基础上通过正交试验优化提取工艺,并评价其抗氧化活性。结果表明:最佳提取工艺条件为超声功率90 W、提取温度60℃、提取时间20 min、乙醇体积分数70%。在此条件下菌株发酵液中的总绿原酸含量达(3.80±0.62)mg/L。提取的发酵液对DPPH、ABTS、羟基自由基的清除率均显著增加,分别为72.18%、73.26%、60.11%,表明其具有较好的抗氧化活性。

关键词：长孢洛德酵母菌绿原酸正交试验抗氧化活性

Strengthening absorption ability of Co-N-C as efficient bifunctional oxygen catalyst by modulating the d band center using MoC

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Green Energy & Environment 2023年第2期8卷 459-469页

作者： Jianwen liu ying Guo xian-zhu Fu Jing-li luo chunyi Zhi Shenzhen Key Laboratory of Polymer Science and Technology Guangdong Research Center for Interfacial Engineering of Functional MaterialsCollege of Materials Science and EngineeringShenzhen University518060China Department of Materials Science and Engineering City University of Hong Kong83 Tat Chee AvenueKowloon TongHong KongChina Department of Chemical and Materials Engineering University of AlbertaEdmontonAlbertaT6G 1H9Canada

Co-N-C is a promising oxygen electrochemical catalyst due to its high stability and good ***,due to the limited adsorption ability improvement for oxygen-containing intermediates,it usually exhibits inadequate catalytic activity with 2-electron pathway and high selectivity of hydrogen ***,the adsorption of Co-N-C to these intermediates is modulated by constructing heterostructures using transition metals and their derivatives based on d-band *** heterostructured nanobelts with MoC core and pomegranate-like carbon shell consisting of Co nanoparticles and N dopant(MoC/Co-N-C)are engineered to successfully modulate the d band center of active Co-N-C sites,resulting in a remarkably enhanced electrocatalysis *** optimally performing MoC/Co-N-C exhibits outstanding bi-catalytic activity and stability for the oxygen electrochemistry,featuring a high wave-half potential of 0.865 V for the oxygen reduction reaction(ORR)and low overpotential of 370 mV for the oxygen evolution reaction(OER)at 10 mA cm^(-2).The zinc air batteries with the MoC/Co-N-C catalyst demonstrate a large power density of 180 mW cm^(-2)and a long cycling lifespan(2000 cycles).The density functional theory calculations with Hubbard correction(DFT+U)reveal the electron transferring from Co to Mo atoms that effectively modulate the d band center of the active Co sites and achieve optimum adsorption ability with"single site double adsorption"mode.

关键词： Bifunctional oxygen catalysts Pomegranate-like shell D band theory Enhanced synergistic effect Rechargeable zinc air battery

Heterotactic Enthalpic Interactions of L-Arginine with 2,2,2-Trifluoroethanol in Aqueous Solutions at 298.15, 303.15 and 310.15 K

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Chemical Research in Chinese Universities 2011年第1期27卷 123-126页

作者： zhu Yan PANG xian-hong yu li Department of Chemistry and Chemical Engineering Taishan Medical University Tai ＇an 271016 P. R. China Key Laboratory of Colloid and Interface Chemistry Ministry of Education Shandong University Jinan 250100 P. R China

The enthalpies of mixing of L-arginine with 2,2,2-trifluoroethanol and their respective enthalpies of dilu- tion in aqueous solutions at 298.15, 303.15 and 310.15 K were determined as a function of the mole fraction by flow microcalorimetric measurement. These experimental results were analyzed to obtain heterotactic enthalpic interaction coeffieients（hxy , hxy , hxy） according to the McMillan-Mayer theory. The hxy coefficients between L-arginine molecule studied and 2,2,2-trifluoroethanol molecule in aqueous solutions at 298.15, 303.15 and 310.15 K were found to be all negative. The results were discussed in terms of solute-solute interaction and solute-solvent interaction.

关键词： L-Arginine 2,2,2-Trifluoroetbanol Solute-solute interaction Heterotactic enthalpic interaction