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Recent advances in the biosynthesis of coumarin and its derivatives

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Green Chemical Engineering 2024年第2期5卷 150-154页

作者： Yusong Zou Yuxi Teng Joy Li yajun Yan School of Chemical Materials and Biomedical EngineeringCollege of EngineeringThe University of GeorgiaAthensGA30602USA North Oconee High School BogartGA30622USA

Coumarin and its derivatives,presenting in many organisms(plants,fungi,and bacteria),are critical metabolites composed of fused benzene andα-pyrone rings.With unique biological and chemical properties,coumarin derivatives possess great technological potential in the agrochemicals,pharmaceuticals,food,and cosmetic industries.The increasing demand for coumarin derivatives accelerates the research in biological and chemical synthesis to provide stable and scalable sources of coumarins.However,the complex structures and unknown pathways have limited the progress in the biosynthesis of coumarin derivatives.Here,we summarize recent developments and provide a detailed analysis of coumarin derivative biosynthetic pathways in different organisms.

关键词： Coumarin derivatives Biosynthetic pathways Biotransformation Metabolic engineering

Camellia sinensis CsMYB4a participates in regulation of stamen growth by interaction with auxin signaling transduction repressor CsAUX/IAA4

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The Crop Journal 2024年第1期12卷 188-201页

作者： Guoliang ma Mingzhuo Li Yingling Wu Changjuan Jiang Yifan Chen Dawei Xing Yue Zhao yajun Liu Xiaolan Jiang Tao Xia Liping Gao School of Life Science Anhui Agricultural UniversityHefei 230036AnhuiChina Plant for Human Health Institute Department of Plant and Microbial BiologyNorth Carolina State UniversityKannapolisNC 28081USA State Key Laboratory of Tea Plant Biology and Utilization/Key Laboratory of Tea Biology and Tea Processing of Ministry of Agriculture/Anhui Provincial Laboratory of Tea Plant Biology and Utilization Anhui Agricultural UniversityHefei 230036AnhuiChina

Subgroup 4(Sg4)members of the R2R3-MYB are generally known as negative regulators of the phenylpropanoid pathway in plants.Our previous research showed that a R2R3-MYB Sg4 member from Camellia sinensis(CsMYB4a)inhibits expression of some genes in the phenylpropanoid pathway,but its physiological function in the tea plant remained unknown.Here,CsMYB4a was found to be highly expressed in anther and filaments,and participated in regulating filament growth.Transcriptome analysis and exogenous auxin treatment showed that the target of CsMYB4a might be the auxin signal pathway.Auxin/indole-3-acetic acid 4(AUX/IAA4),a repressor in auxin signal transduction,was detected from a yeast two-hybrid screen using CsMYB4a as bait.Gene silencing assays showed that both CsIAA4 and CsMYB4a regulate filament growth.Tobacco plants overexpressing CsIAA4 were insensitive to exogenous a-NAA,consistent with overexpression of CsMYB4a.Protein-protein interaction experiments revealed that CsMYB4a interacts with N-terminal of CsIAA4 to prevent CsIAA4 degradation.Knock out of the endogenous NtIAA4 gene,a CsIAA4 homolog,in tobacco alleviated filament growth inhibition and a-NAA insensitivity in plants overexpressing CsMYB4a.All results strongly suggest that CsMYB4a works synergistically with CsIAA4 and participates in regulation of the auxin pathway in stamen.

关键词： AUX/IAA4 Auxin signaling CsMYB4a Subgroup 4 R2R3-MYB

Regulating surface electron structure of PtNi nanoalloy via boron doping for high‐current‐density Li‐O2 batteries with low overpotential and long‐life cyclability

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Smartmat 2024年第1期5卷 110-120页

作者： yajun Ding Yuanchao Huang Yuejiao Li Tao Zhang Zhong‐Shuai Wu State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalianChina State Key Laboratory of Silicon materials and School of materials Science and Engineering Zhejiang UniversityHangzhouChina Institute of Advanced Semiconductors Hangzhou Innovation CenterZhejiang UniversityHangzhouChina University of Chinese Academy of Sciences BeijingChina State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghaiChina Dalian National Laboratory for Clean Energy Chinese Academy of SciencesDalianChina

The realization of high‐efficiency,reversible,stable,and safe Li‐O2 batteries is severely hindered by the large overpotential and side reactions,especially at high rate conditions.Therefore,rational design of cathode catalysts with high activity and stability is crucial to overcome the terrible issues at high current density.Herein,we report a surface engineering strategy to adjust the surface electron structure of boron(B)‐doped PtNi nanoalloy on carbon nanotubes(PtNiB@CNTs)as an efficient bifunctional cathodic catalyst for high‐rate and long‐life Li‐O2 batteries.Notably,the Li‐O2 batteries assembled with as‐prepared PtNiB@CNT catalyst exhibit ultrahigh discharge capacity of 20510 ma·h/g and extremely low overpotential of 0.48 V at a high current density of 1000 ma/g,both of which outperform the most reported Pt‐based catalysts recently.Meanwhile,our Li‐O2 batteries offer excellent rate capability and ultra‐long cycling life of up to 210 cycles at 1000 ma/g under a fixed capacity of 1000 ma·h/g,which is two times longer than those of Pt@CNTs and PtNi@CNTs.Furthermore,it is revealed that surface engineering of PtNi nanoalloy via B doping can efficiently tailor the electron structure of nanoalloy and optimize the adsorption of oxygen species,consequently delivering excellent Li‐O2 battery performance.Therefore,this strategy of regulating the nanoalloy by doping nonmetallic elements will pave an avenue for the design of high‐performance catalysts for metal‐oxygen batteries.

关键词： B doping bifunctional catalyst Li‐O2 battery low charge overpotential PtNi nanoalloy

Cu-catalyzed regioselective diborylation of 1,3-enynes for the efficient synthesis of 1,4-diborylated allenes

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Chinese Chemical Letters 2024年第5期35卷 141-144页

作者： Wujun Jian Mong-Feng Chiou yajun Li Hongli Bao Song Yang National Key Laboratory of Green Pesticide Key Laboratory of Green Pesticide and Agricultural BioengineeringMinistry of EducationCenter for R&D of Fine Chemicals of Guizhou UniversityGuiyang 550025China Strait Institute of Flexible Electronics(SIFE Future Technologies)Fujian Normal UniversityFuzhou 350117China Key Laboratory of Coal to Ethylene Glycol and Its Related Technology State Key Laboratory of Structural ChemistryFujian Institute of Research on the Structure of MatterUniversity of Chinese Academy of SciencesFuzhou 350002China

Borylation of 1,3-enynes with bis(boronate)compounds often ends up with the formation of hydroborylated products,leaving the diborylation of 1,3-enynes for the formation of 1,4-diborylated allenes to be challenging.Herein,a copper-catalyzed chemo-,regio-,and stereo-selective diborylation of 1,3-enynes for the efficient construction of 1,4-diborylated allenes under base-free conditions was reported.A wide range of 1,3-enynes bearing various functional groups can participant in the reaction and afforded the corresponding 1,4-diborylated allenes in good to excellent yields,which was enabled by the protocol of Bpin to BF3K conversion.the borylcopper species was supposed to selectively attack the C-C triple bond of the 1,3-enynes.

关键词： Copper catalysis Regioselective 1,3-Enynes Borylation Allenes

A Deep Learning Approach to Shape Optimization Problems for Flexoelectric materials Using the Isogeometric Finite Element Method

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1935-1960页

作者： Yu Cheng yajun Huang Shuai Li Zhongbin Zhou Xiaohui Yuan Yanming Xu College of Architecture and Civil Engineering Xinyang Normal UniversityXinyang464000China Henan Unsaturated Soil and Special Soil Engineering Technology Research Center Xinyang Normal UniversityXinyang464000China College of Intelligent Construction Wuchang University of TechnologyWuhan430223China College of Civil Engineering and Architecture Dalian UniversityDalian116622China Henan International Joint Laboratory of Structural Mechanics and Computational Simulation School of Architecture and Civil EngineeringHuanghuai UniversityZhumadian463000China

A new approach for flexoelectricmaterial shape optimization is proposed in this study.In this work,a proxymodel based on artificial neural network(ANN)is used to solve the parameter optimization and shape optimization problems.To improve the fitting ability of the neural network,we use the idea of pre-training to determine the structure of the neural network and combine different optimizers for training.The isogeometric analysis-finite element method(IGA-FEM)is used to discretize the flexural theoretical formulas and obtain samples,which helps ANN to build a proxy model from the model shape to the target value.The effectiveness of the proposed method is verified through two numerical examples of parameter optimization and one numerical example of shape optimization.

关键词： Shape optimization deep learning flexoelectric structure finite element method isogeometric

Modulated symbol-based one-time pad secure transmission scheme using physical layer keys

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Science China(Information Sciences) 2024年第1期67卷 221-239页

作者： Xiaoyan HU Zheng WAN Kaizhi HUANG Liang JIN Mengyao YAN yajun CHEN Jinmei YANG Information Engineering University Purple Mountain Laboratories for Network and Communication Security

This paper proposes a novel modulated symbols-based one-time pad(SOTP) secure transmission scheme using physical layer keys.Unlike classical physical layer key generation and exclusive OR(XOR)encryption in the discrete binary space,we design a framework for modulated symbols-based one-time pad(OTP) encryption,where the cryptographic primitive and mathematical model of SOTP is given to build a practical cryptographic protocol.Compared with existing physical layer encryption(PLE) schemes,we provide rigorous proof that the framework can meet perfect secrecy and correctness requirements.In addition,we provide a specific scheme of physical layer OTP secure transmission for quadrature amplitude modulation(QAM) and phase-shift keying(PSK) symbols based on physical layer keys.This scheme realizes the unification of bit encryption and symbol encryption,which can adaptively select the quantization level according to the signal-to-noise ratio(SNR) to minimize the symbol error rate(SER).Further,we analyze the performance quantitatively and derive the closed-form expressions of SER,which indicates that the proposed scheme has a lower SER.Finally,simulation results verify that the proposed symbol-wise OTP secure transmission scheme can achieve perfect secrecy and high reliability.

关键词： physical layer security one-time pad wireless channel physical layer encryption perfect secrecy

Three-dimensional parametric contact analysis of planetary roller screw mechanism and its application in grouping for selective assembly

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Frontiers of Mechanical Engineering 2024年第1期19卷 53-72页

作者： Huilin HE Peitang WEI Huaiju LIU Xuesong DU Rui HU Genshen LIU yajun WU State Key Laboratory of Mechanical Transmission for Advanced Equipment Chongqing UniversityChongqing 400044China Taiyuan Heavy machinery Group Co. Ltd.Taiyuan 030024China

The planetary roller screw mechanism(PRSM)is a novel precision transmission mechanism that realizes the conversion between linear and rotary motions.The contact characteristics of helical surfaces directly determine PRSM’s performance in load-carrying capacity and transmission accuracy.Therefore,studying the contact characteristics of PRSM forms the fundamental basis for enhancing its transmission performance.In this study,a three-dimensional parametric analysis method of contact characteristics is proposed based on the PRSM meshing principle and PyVista(a high-level API to the Visualization Toolkit).The proposed method considers the influence of machining errors among various thread teeth.The effects of key machining errors on contact positions and axial clearance,as well as their sensitivities,are analyzed.With excellent solution accuracy,this method exhibits higher calculation efficiency and stronger robustness than the analytical and numerical meshing models.The influence of nominal diameter and pitch errors of the screw,roller,and nut on the axial clearance follows a linear relationship,whereas flank angle errors have negligible effects on the axial clearance.The corresponding influence coefficients for these three machining errors on the axial clearance are 0.623,0.341,and 0.036.The variations in contact positions caused by individual errors are axisymmetric.Flank angle errors and roller diameter errors result in linear displacements of the contact points,whereas pitch errors cause the contact points to move along the arc of the roller diameter.Based on the proposed threedimensional parametric contact characteristics analysis method,the Fuzzy C-Means clustering algorithm considering error sensitivity is utilized to establish a component grouping technique in the selective assembly of critical PRSM components,ensuring the rational and consistent clearances based on the given component’s machining errors.This study provides effective guidance for analyzing contact characteristics and grouping in selective ass

关键词： planetary roller screw mechanism(PRSM) contact position axial clearance machining error grouping for selective assembly

Genetic structure of Aedes albopictus(Diptera:Culicidae)populations in China and relationship with the knockdown resistance mutations

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Infectious Diseases of Poverty 2023年第3期12卷 31-40页

作者： Wenqi Shan Hao Yuan Hanming Chen Haowei Dong Qiuming Zhou Feng Tao Jie Bai Huiying Chen Yajun Ma Heng Peng Department of Naval Medicine Naval Medical UniversityShanghai 200433China Department of Medical Microbiology and Parasitology College of Basic Medical SciencesNaval Medical UniversityShanghai 200433China

Background Mosquito control is needed to prevent dengue fever, which is mainly spread byAedes albopictus in China. Application of insecticides is one of the main mosquito control methods;however, this approach can fail due to the knockdown resistance (kdr) gene mutation that causes decreased sensitivity to insecticides inAe. albopictus. Thekdr mutation patterns among different regions in China differ significantly. However, the underlying mechanism and factors that influencekdr mutation remain unclear. To explore the potential influence of genetic background on the development of insecticide resistance inAe. albopictus, we analyzed the genetic structure ofAe. albopictus populations in China and its correlation with majorkdr mutations.Methods We collectedAe. albopictus from 17 sites in 11 provinces (municipalities) across China from 2016 to 2021 and extracted the genomic DNA from individual adult mosquitoes. We selected eight microsatellite loci for genotyping, and based on microsatellite scores, we estimated intraspecific genetic diversity, population structure, and effective population size. The association between the intrapopulation genetic variation and F1534 mutation rate was evaluated by the Pearson correlation coefficient.Results Based on variation analysis of the microsatellite loci of 453 mosquitoes representing 17 populations throughout China, more than 90% of the variation occurred within individuals, whereas only about 9% of the variation occurred among populations, indicating that field populations ofAe. albopictus are highly polymorphic. The northern populations tended to belong to gene pool I (BJFT 60.4%, SXXA 58.4%, SDJN 56.1%, SXYC 46.8%), the eastern populations tended to belong to pool III (SH 49.5%, JZHZ 48.1%), and the southern populations tended to belong to three different gene pools. Moreover, we observed that the greater the fixation index (FST), the lower the wild-type frequency of F1534 ofVSGC.Conclusions The degree of genetic differentiation amongAe. albopictus populations in China was

关键词： Aedes albopictus Population structure Microsatellite Knockdown resistance China

Ferroptosis mechanism and Alzheimer's disease

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Neural Regeneration Research 2024年第8期19卷 1741-1750页

作者： Lina Feng Jingyi Sun Ling Xia Qiang Shi yajun Hou Lili Zhang Mingquan Li Cundong Fan Baoliang Sun Shandong Key Laboratory of TCM Multi-Target Intervention and Disease Control the Second Affiliated Hospital of Shandong First Medical UniversityTaianShandong ProvinceChina Department of Internal Medicine Taian Traffic HospitalTaianShandong ProvinceChina Department of Neurology the Third Affiliated Clinical Hospital of Changchun University of Chinese MedicineChangchunJilin ProvinceChina

Regulated cell death is a genetically determined form of programmed cell death that commonly occurs during the development of living organisms.This process plays a crucial role in modulating homeostasis and is evolutionarily conserved across a diverse range of living organisms.Ferroptosis is a classic regulatory mode of cell death.Extensive studies of regulatory cell death in Alzheimer’s disease have yielded increasing evidence that fe rroptosis is closely related to the occurrence,development,and prognosis of Alzheimer’s disease.This review summarizes the molecular mechanisms of ferroptosis and recent research advances in the role of ferro ptosis in Alzheimer’s disease.Our findings are expected to serve as a theoretical and experimental foundation for clinical research and targeted therapy for Alzheimer’s disease.

关键词： Alzheimer’s disease apolipoprotein E Fe^(2+) ferroptosis glial cell glutathione peroxidase 4 imbalance in iron homeostasis lipid peroxidation regulated cell death system Xc^(-)