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Deciphering fungal metabolon coupling tandem inverse-electrondemand Diels-Alder reaction and semipinacol rearrangement for the biosynthesis of spiro polycyclic alkaloids

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Science China Chemistry 2025年第1期68卷 288-296页

作者： Shuai Liu Wen-qiang xu Ying-Tong Di Man-Cheng Tang Ding-Kang Chen Ming-Ming Cao Yao-Wen Chang Hong-Yu Tang Chun-Mao Yuan Jun-Bo Yang Zhi-Li Zuo Han Guo Zi-Fei xu Ying Zeng Yun-Dong Wu Xiao-Jiang Hao Key Laboratory of Phytochemistry and Natural Medicines (Chinese Academy of Sciences) Kunming Institute of Botany Chinese Academy of Sciences University of Chinese Academy of Sciences Lab of Computational Chemistry and Drug Design State Key Laboratory of Chemical Oncogenomics Peking University Shenzhen Graduate School Shenzhen Bay Laboratory State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical University Molecular Biology Experimental Center Germplasm Bank of Wild Species in Southwest China Kunming Institute of Botany Chinese Academy of Sciences Yunnan Key Laboratory for Wild Plant Resources Kunming Institute of Botany Chinese Academy of Sciences Research Unit of Chemical Biology of Natural Anti-Virus Products Chinese Academy of Medical Sciences

In the intricate process of natural product biosynthesis, a metabolon can enhance metabolic flux by associating sequential enzymes. A fungal metabolon, comprising of flavin-dependent monooxygenase Spe F and P450 monooxygenase Spe G, is identified in the biosynthesis of spiro polycyclic alkaloids(+)-notoamide B and its diastereomer(+)-versicolamide B. Using notoamide E as a substance, Spe F/Spe G metabolon can control the stereoselectivity of its 2,3-epoxidation, followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-m A with dienyl iminium unit. Subsequently,(+)-notoamide B and(+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol rearrangement. This provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

关键词： metabolon Diels-Alder reaction semipinacol rearrangement biosynthesis notoamides spiro polycyclic alkaloids

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Molecular simulation study of the microstructures and properties of pyridinium ionic liquid[HPy][BF_(4)]mixed with acetonitrile

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原子与分子物理学报 2025年第4期42卷 27-32页

作者： xu Jian-qiang MA Zhao-Peng CHENG Si LIU Zhi-Cong ZHU Guang-Lai Department of Physics School of Physics and Electronic InformationAnhui Normal UniversityWuhu 241002China

The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this *** following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution *** results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient ***,the excess molar volume initially decreases,reaches a minimum,and then *** rules of radial distribution functions(RDFs)of characteristic atoms are *** increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then *** indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.

关键词： Pyridinium ionic liquids Thermodynamic properties Molecular dynamics simulation Radial distribution functions

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Quasi-MOF-immobilized metal nanoparticles for synergistic catalysis

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Science China Chemistry 2020年第11期63卷 1601-1607页

作者： Liyu Chen Nobuko Tsumori qiang xu AIST-Kyoto University Chemical Energy Materials Open Innovation Laboratory(ChEM-OIL) National Institute of Advanced Industrial Science and Technology(AIST)YoshidaSakyo-kuKyoto 606-8501Japan Toyama National College of Technology 13 Hongo-machiToyama 939-8630Japan School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China

Through partial deligandation of metal-organic frameworks(MOFs),quasi-MOFs with a transition structure between MOFs and metal compounds(such as metal oxides,nitrides,sulfides,and phosphides)can be ***-MOFs can not only retain the porous structure of MOFs to a certain extent,but also expose the inorganic nodes to the guest species(e.g.,metal nanoparticles)to show enhanced metal-support interaction for synergistic *** concept was first demonstrated by our group through calcining Au/MIL-101 at different temperatures under Ar flow to adjust the interface between Au nanoparticles and the inorganic Cr–O *** obtained Au/quasi-MIL-101 showed superior enhanced catalytic activity in the oxidation of carbon *** study has inspired further research interest to fabricate other quasi-MOFs through controlled deligandation of mono-and bimetallic MOFs and their composites for the design of efficient catalysts.

关键词： MOFs metal nanoparticles metal-support interaction quasi-MOFs synergistic catalysis

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Function spaces on local fields

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Science China Mathematics 2006年第1期49卷 66-74页

作者： SU Weiyi xu qiang Department of Mathematics Nanjing University Nanjing 210093 China Department of Mathematics Nanjing University Nanjing 210093 China

We study the function spaces on local fields in this paper, such as Triebel Btype and F-type spaces, Holder type spaces, Sobolev type spaces, and so on, moreover,study the relationship between the p-type derivatives and the Holder type spaces. Our obtained results show that there exists quite difference between the functions defined on Euclidean spaces and local fields, respectively. Furthermore, many properties of functions defined on local fields motivate the new idea of solving some important topics on fractal analysis.

关键词： local Held character group Triebel B-type and F-type spaces Holder type space.

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Implicit finite difference method for fractional percolation equation with Dirichlet and fractional boundary conditions

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Applied Mathematics and Mechanics(English Edition) 2016年第3期37卷 403-416页

作者： Boling GUO qiang xu Zhe YIN Institute of Applied Physics and Computational Mathematics Beijing 100088 China School of Mathematical Sciences Shandong Normal University Jinan 250014 China

An implicit finite difference method is developed for a one-dimensional frac- tional percolation equation （FPE） with the Dirichlet and fractional boundary conditions. The stability and convergence are discussed for two special cases, i.e., a continued seep- age flow with a monotone percolation coefficient and a seepage flow with the fractional Neumann boundary condition. The accuracy and efficiency of the method are checked with two numerical examples.

关键词： fractional percolation equation (FPE) Riemann-Liouville derivative frac-tional boundary condition finite difference method stability and convergence Toeplitzmatrix

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Differential surface uplift: Cenozoic paleoelevation history of the Tibetan Plateau

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Science China Earth Sciences 2016年第11期59卷 2105-2120页

作者： LIU XiaoHui xu qiang DING Lin Key Laboratory of Continental Collision and Plateau Uplift Institute of Tibetan Plateau Research Chinese Academy of Sciences Center for Excellence in Tibetan Plateau Earth Science Chinese Academy of Sciences College of Resources and Environment University of Chinese Academy of Sciences

The surface uplift history of the Tibetan Plateau has provided a key boundary criterion for various geological, climatic,and environmental events since the Cenozoic. The paleoelevation history of the plateau is organically associated with interactions amongst deep geodynamics, earth surface processes, and climate change. Understanding of plateau uplift history has been advanced by the development of a number of paleoaltimetries and their application to studies of the Tibetan Plateau: the paleogeomorphic scenario for the Early Eocene Tibetan Plateau is thought to include two high mountains, the ca. 4500 m Gangdese Mountains to the south, and the ca. 5000 m qiangtang Center Watershed Mountains to the north. Between these ranges, a low-elevation basin(ca. 2500 m) is thought to have been present. The Himalayas in the southern Tibetan Plateau was close to sea level at this time,while the Hoh Xil Basin in the north reached an elevation of no more than 1500 m. Thus, the so-called "Roof of the World" Tibetan Plateau formed subsequent to the Miocene. Nevertheless,, the uplift histories of the different terranes that comprise this plateau currently remain unclear, which constrains the uplift history reconstruction of the entire Tibetan Plateau. Additional paleoelevation data from different areas, obtained using multi-paleoaltimeters, is required to resolve the forms and processes of Tibetan Plateau uplift and extension.

关键词： Paleoelevation Differential surface uplift Cenozoic Tibetan Plateau

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Micro-mechanism of metal magnetic memory signal variation during fatigue

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International Journal of Minerals,Metallurgy and Materials 2014年第3期21卷 259-265页

作者： Ming-xiu xu Zhang-hua Chen Min-qiang xu School of Mathematics and Physics University of Science and Technology Beijing Division of Vehicle Dynamics & Control Harbin Institute of Technology

Tensile fatigue tests were designed to study the relation between the tangential magnetic memory signal and dislocations. According to experimental results, in the early stage of fatigue, the magnetic signal and the dislocation density rapidly increase; while in the middle stage, the magnetic signal gradually increases, the dislocation density remains steady, and only the dislocation structure develops. On the other hand, in the later stage, the magnetic signal once again increases rapidly, the dislocation structure continues to develop, and microscopic cracks are formed. Analysis reveals that the dislocations block the movement of the domain wall, and the area of dislocation accumulation thus becomes an internal magnetic source and scatters a field outward. In addition, the magnetic memory field strengthens with increasing dislocation density and complexity of the dislocation structure. Accordingly, the dislocation pinning factor related with the dislocation density and the dislocation structure has been proposed to characterize the effect of dislocations on the magnetic memory signal. The magnetic signal strengthens with an increase in the dislocation pinning factor.

关键词： fatigue of materials metal magnetic memory dislocations magnetic fields

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Coupled elasto-plasticity damage constitutive models for concrete

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第4期14卷 256-267页

作者： qiang xu Jian-yun CHEN Jing LI Gang xu State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology School of Civil and Hydraulic Engineering Dalian University of Technology Plan and Design Institute of Daqing Oilfield Communication Company

The paper is to design and construct a coupled elasto-plasticity damage constitutive model for *** on the energy dissipation principle,the Hsieh-Ting-Chen four-parameter yield function is *** model can reflect different strength characteristics of concrete in tension and compression,and reduce the limitation and lacuna of the traditional damage constitutive models for ***,numerical test for concrete stress-strain relation under uniaxial tension and compression is ***,the damage process of concrete gravity dam is calculated and analyzed in seismic *** with other damage constitutive models,the proposed model contains only one unknown parameter and the other parameters can be found in the Hsieh-Ting-Chen four-parameter yield *** same damage evolution law,which is used for tension and compression,is good for determining stress-strain constitutive and damage characteristics in complex stress *** coupled damage constitutive models can be applied in analyzing damage of concrete gravity dam and arch dam.

关键词： Concrete Damage constitutive models Hsieh-Ting-Chen four-parameter yield function Uniaxial tension Uniaxial compression Gravity dam Arch dam

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The primary influence of shear band evolution on the slope bearing capacity

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第4期15卷 1023-1037页

作者： Lanting Wei qiang xu Shanyong Wang xu Ji Chengdu University of Technology ChengduChina Priority Research Centre for Geotechnical Science and Engineering School of EngineeringUniversity of NewcastleNewcastleAustralia

Slope bearing capacity is one of the most important characteristics in slope engineering and is strongly influenced by weak planes,loading conditions,and slope *** presenting the evolution of slip surfaces,this paper explored how the slope bearing capacity is affected by widely observed influencing *** initiation and propagation of slip surfaces are presented in laboratory model tests of slope using the transparent soil *** band evolution under various weak planes,loading conditions,and slope geometries were experimentally presented,and slope bearing capacities were analyzed with the process of shear band *** paper verified that slip surface morphologies have a strong relation with the slope bearing *** same slip surface morphology can have different evolutionary *** this case,it is the shear band evolution that determines the slope bearing capacity,not the morphology of the slip *** influencing factors such as pre-existing weak planes,loading conditions,and slope geometry strongly affect the slope bearing capacity as these factors govern the process of shear band evolution inside the slope.

关键词： Slope bearing capacity Shear band evolution Failure mechanism Transparent soil

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Blow-up of Solutions for a Time-space Fractional Evolution System

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Acta Mathematica Sinica,English Series 2013年第6期29卷 1067-1074页

作者： Yong qiang xu Zhong TAN Department of Mathematics and Information Sciences Zhangzhou Normal University School of Mathematical Sciences Xiamen University

In this paper, firstly, we study the local existence and uniqueness of mild solutions for fractional evolution systems with nonlocal in time nonlinearity. Then, we claim that such a mild solution is weak solution of t... 详细信息

关键词： Local existence fractional integrals and derivatives evolution systems

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